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Sample records for mouse islet insulin

  1. Glucose metabolism, islet architecture, and genetic homogeneity in imprinting of [Ca2+](i and insulin rhythms in mouse islets.

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    Craig S Nunemaker

    2009-12-01

    Full Text Available We reported previously that islets isolated from individual, outbred Swiss-Webster mice displayed oscillations in intracellular calcium ([Ca2+](i that varied little between islets of a single mouse but considerably between mice, a phenomenon we termed "islet imprinting." We have now confirmed and extended these findings in several respects. First, imprinting occurs in both inbred (C57BL/6J as well as outbred mouse strains (Swiss-Webster; CD1. Second, imprinting was observed in NAD(PH oscillations, indicating a metabolic component. Further, short-term exposure to a glucose-free solution, which transiently silenced [Ca2+](i oscillations, reset the oscillatory patterns to a higher frequency. This suggests a key role for glucose metabolism in maintaining imprinting, as transiently suppressing the oscillations with diazoxide, a K(ATP-channel opener that blocks [Ca2+](i influx downstream of glucose metabolism, did not change the imprinted patterns. Third, imprinting was not as readily observed at the level of single beta cells, as the [Ca2+](i oscillations of single cells isolated from imprinted islets exhibited highly variable, and typically slower [Ca2+](i oscillations. Lastly, to test whether the imprinted [Ca2+](i patterns were of functional significance, a novel microchip platform was used to monitor insulin release from multiple islets in real time. Insulin release patterns correlated closely with [Ca2+](i oscillations and showed significant mouse-to-mouse differences, indicating imprinting. These results indicate that islet imprinting is a general feature of islets and is likely to be of physiological significance. While islet imprinting did not depend on the genetic background of the mice, glucose metabolism and intact islet architecture may be important for the imprinting phenomenon.

  2. Reversed-phase high-performance liquid chromatographic analyses of insulin biosynthesis in isolated rat and mouse islets

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    Linde, S; Hansen, Bruno A.; Welinder, B S

    1989-01-01

    deletion compared to rat C-peptide I. A marked species difference in the ratio between insulin I and II was observed, i.e., 2:1 in the rat and 1:2 in the mouse. Pulse-chase experiments in rat islets have demonstrated that the ratio between insulin I and II in newly synthesized insulin is higher than...

  3. Direct effect of gonadal and contraceptive steroids on insulin release from mouse pancreatic islets in organ culture

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    Nielsen, Jens Høiriis

    1984-01-01

    Sex steroids are supposed to contribute to the normal glucose homeostasis and to the altered glucose and insulin metabolism in pregnancy and during contraception. In the present study isolated mouse pancreatic islets were maintained in tissue culture medium RPMI 1640 supplemented with 0.5% newborn...... calf serum and 100 ng/ml of one of the following steroids: oestradiol, progesterone, testosterone, megestrol acetate, medroxyprogesterone, chlormadinone acetate, norethynodrel, norethindrone acetate, and ethynyloestradiol. Release of insulin to the culture medium was measured during a 2 week culture...... in the presence of oestradiol, progesterone, or testosterone were subjected to 30 min stimulation with 5.5, 11, 22 mmol/l glucose, only the progesterone-treated islets released more insulin in response to glucose than the control islets. It is concluded that progesterone and its derivatives have a direct effect...

  4. Inhibition of insulin release by cyproheptadine: Effects on 3',5'-cyclic-AMP-content and /sup 45/Ca-accumulation of incubated mouse islets

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    Joost, H G; Beckmann, J; Lenzen, S; Hasselblatt, A [Goettingen Univ. (F.R. Germany)

    1976-01-01

    Cyproheptadine (1, 10 and 100 ..mu..m) significantly reduced insulin release from isolated mouse islets in response to glucose. In contrast, 1 mM cyproheptadine induced a large release of insulin into the incubation medium probably due to islet cell damage, since the islets had lost a considerable amount of their protein content. 3',5'-cyclic-AMP-levels of the islets were not significantly affected by 10 ..mu..M cyproheptadine in the presence as well as in the absence of theophylline (10 mM). As the inhibitory effect of cyproheptadine on insulin release was correlated with reduced accumulation of calcium-45, the agent may inhibit insulin release by interfering with the calcium handling of the ..beta..-cell.

  5. Compensatory hyperinsulinemia in high-fat diet-induced obese mice is associated with enhanced insulin translation in islets

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    Kanno, Ayumi, E-mail: akanno@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Asahara, Shun-ichiro, E-mail: asahara@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Masuda, Katsuhisa, E-mail: katsuhisa.m.0707@gmail.com [Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe 654-0142 (Japan); Matsuda, Tomokazu, E-mail: tomokazu@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Kimura-Koyanagi, Maki, E-mail: koyanagi@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Seino, Susumu, E-mail: seino@med.kobe-u.ac.jp [Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047 (Japan); Ogawa, Wataru, E-mail: ogawa@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Kido, Yoshiaki, E-mail: kido@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Division of Medical Chemistry, Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe 654-0142 (Japan)

    2015-03-13

    A high-fat diet (HF) is associated with obesity, insulin resistance, and hyperglycemia. Animal studies have shown compensatory mechanisms in pancreatic β-cells after high fat load, such as increased pancreatic β-cell mass, enhanced insulin secretion, and exocytosis. However, the effects of high fat intake on insulin synthesis are obscure. Here, we investigated whether insulin synthesis was altered in correlation with an HF diet, for the purpose of obtaining further understanding of the compensatory mechanisms in pancreatic β-cells. Mice fed an HF diet are obese, insulin resistant, hyperinsulinemic, and glucose intolerant. In islets of mice fed an HF diet, more storage of insulin was identified. We analyzed insulin translation in mouse islets, as well as in INS-1 cells, using non-radioisotope chemicals. We found that insulin translational levels were significantly increased in islets of mice fed an HF diet to meet systemic demand, without altering its transcriptional levels. Our data showed that not only increased pancreatic β-cell mass and insulin secretion but also elevated insulin translation is the major compensatory mechanism of pancreatic β-cells. - Highlights: • More stored insulin was recognized in islets of mice fed a high-fat diet. • Insulin translation was not enhanced by fatty acids, but by insulin demand. • Insulin transcription was not altered in islets of mice fed a high-fat diet. • Insulin translation was markedly enhanced in islets of mice fed a high-fat diet. • Non-radioisotope chemicals were used to measure insulin translation in mouse islets.

  6. Compensatory hyperinsulinemia in high-fat diet-induced obese mice is associated with enhanced insulin translation in islets

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    Kanno, Ayumi; Asahara, Shun-ichiro; Masuda, Katsuhisa; Matsuda, Tomokazu; Kimura-Koyanagi, Maki; Seino, Susumu; Ogawa, Wataru; Kido, Yoshiaki

    2015-01-01

    A high-fat diet (HF) is associated with obesity, insulin resistance, and hyperglycemia. Animal studies have shown compensatory mechanisms in pancreatic β-cells after high fat load, such as increased pancreatic β-cell mass, enhanced insulin secretion, and exocytosis. However, the effects of high fat intake on insulin synthesis are obscure. Here, we investigated whether insulin synthesis was altered in correlation with an HF diet, for the purpose of obtaining further understanding of the compensatory mechanisms in pancreatic β-cells. Mice fed an HF diet are obese, insulin resistant, hyperinsulinemic, and glucose intolerant. In islets of mice fed an HF diet, more storage of insulin was identified. We analyzed insulin translation in mouse islets, as well as in INS-1 cells, using non-radioisotope chemicals. We found that insulin translational levels were significantly increased in islets of mice fed an HF diet to meet systemic demand, without altering its transcriptional levels. Our data showed that not only increased pancreatic β-cell mass and insulin secretion but also elevated insulin translation is the major compensatory mechanism of pancreatic β-cells. - Highlights: • More stored insulin was recognized in islets of mice fed a high-fat diet. • Insulin translation was not enhanced by fatty acids, but by insulin demand. • Insulin transcription was not altered in islets of mice fed a high-fat diet. • Insulin translation was markedly enhanced in islets of mice fed a high-fat diet. • Non-radioisotope chemicals were used to measure insulin translation in mouse islets

  7. Magnetic resonance imaging of mouse islet grafts labeled with novel chitosan-coated superparamagnetic iron oxide nanoparticles.

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    Jyuhn-Huarng Juang

    Full Text Available To better understand the fate of islet isografts and allografts, we utilized a magnetic resonance (MR imaging technique to monitor mouse islets labeled with a novel MR contrast agent, chitosan-coated superparamagnetic iron oxide (CSPIO nanoparticles.After being incubated with and without CSPIO (10 µg/ml, C57BL/6 mouse islets were examined under transmission electron microscope (TEM and their insulin secretion was measured. Cytotoxicity was examined in α (αTC1 and β (NIT-1 and βTC cell lines as well as islets. C57BL/6 mice were used as donors and inbred C57BL/6 and Balb/c mice were used as recipients of islet transplantation. Three hundred islets were transplanted under the left kidney capsule of each mouse and then MR was performed in the recipients periodically. At the end of study, the islet graft was removed for histology and TEM studies.After incubation of mouse islets with CSPIO (10 µg/mL, TEM showed CSPIO in endocytotic vesicles of α- and β-cells at 8 h. Incubation with CSPIO did not affect insulin secretion from islets and death rates of αTC1, NIT-1 and βTC cell lines as well as islets. After syngeneic and allogeneic transplantation, grafts of CSPIO-labeled islets were visualized on MR scans as persistent hypointense areas. At 8 weeks after syngeneic transplantation and 31 days after allogeneic transplantation, histology of CSPIO-labeled islet grafts showed colocalized insulin and iron staining in the same areas but the size of allografts decreased with time. TEM with elementary iron mapping demonstrated CSPIO distributed in the cytoplasm of islet cells, which maintained intact ultrastructure.Our results indicate that after syngeneic and allogeneic transplantation, islets labeled with CSPIO nanoparticles can be effectively and safely imaged by MR.

  8. The F-actin modifier villin regulates insulin granule dynamics and exocytosis downstream of islet cell autoantigen 512

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    Hassan Mziaut

    2016-08-01

    Full Text Available Objective: Insulin release from pancreatic islet β cells should be tightly controlled to avoid hypoglycemia and insulin resistance. The cortical actin cytoskeleton is a gate for regulated exocytosis of insulin secretory granules (SGs by restricting their mobility and access to the plasma membrane. Prior studies suggest that SGs interact with F-actin through their transmembrane cargo islet cell autoantigen 512 (Ica512 (also known as islet antigen 2/Ptprn. Here we investigated how Ica512 modulates SG trafficking and exocytosis. Methods: Transcriptomic changes in Ica512−/− mouse islets were analyzed. Imaging as well as biophysical and biochemical methods were used to validate if and how the Ica512-regulated gene villin modulates insulin secretion in mouse islets and insulinoma cells. Results: The F-actin modifier villin was consistently downregulated in Ica512−/− mouse islets and in Ica512-depleted insulinoma cells. Villin was enriched at the cell cortex of β cells and dispersed villin−/− islet cells were less round and less deformable. Basal mobility of SGs in villin-depleted cells was enhanced. Moreover, in cells depleted either of villin or Ica512 F-actin cages restraining cortical SGs were enlarged, basal secretion was increased while glucose-stimulated insulin release was blunted. The latter changes were reverted by overexpressing villin in Ica512-depleted cells, but not vice versa. Conclusion: Our findings show that villin controls the size of the F-actin cages restricting SGs and, thus, regulates their dynamics and availability for exocytosis. Evidence that villin acts downstream of Ica512 also indicates that SGs directly influence the remodeling properties of the cortical actin cytoskeleton for tight control of insulin secretion. Keywords: F-actin, Granules, Ica512, Insulin, Secretion, Villin

  9. LH-21 and abnormal cannabidiol improve β-cell function in isolated human and mouse islets through GPR55-dependent and -independent signalling.

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    Ruz-Maldonado, Inmaculada; Pingitore, Attilio; Liu, Bo; Atanes, Patricio; Huang, Guo Cai; Baker, David; Alonso, Francisco José; Bermúdez-Silva, Francisco Javier; Persaud, Shanta J

    2018-04-01

    To examine the effects of Abn-CBD (GPR55 agonist) and LH-21 (CB1 antagonist) on human and mouse islet function, and to determine signalling via GPR55 using islets from GPR55 -/- mice. Islets isolated from human organ donors and mice were incubated in the absence or presence of Abn-CBD or LH-21, and insulin secretion, [Ca 2+ ] i, cAMP , apoptosis, β-cell proliferation and CREB and AKT phosphorylation were examined using standard techniques. Abn-CBD potentiated glucose-stimulated insulin secretion and elevated [Ca 2+ ] i in human islets and islets from both GPR55 +/+ and GPR55 -/- mice. LH-21 also increased insulin secretion and [Ca 2+ ] i in human islets and GPR55 +/+ mouse islets, but concentrations of LH-21 up to 0.1 μM were ineffective in islets from GPR55 -/- mice. Neither ligand affected basal insulin secretion or islet cAMP levels. Abn-CBD and LH-21 reduced cytokine-induced apoptosis in human islets and GPR55 +/+ mouse islets, and these effects were suppressed after GPR55 deletion. They also increased β-cell proliferation: the effects of Abn-CBD were preserved in islets from GPR55 -/- mice, while those of LH-21 were abolished. Abn-CBD and LH-21 increased AKT phosphorylation in mouse and human islets. This study showed that Abn-CBD and LH-21 improve human and mouse islet β-cell function and viability. Use of islets from GPR55 -/- mice suggests that designation of Abn-CBD and LH-21 as a GPR55 agonist and a CB1 antagonist, should be revised. © 2017 John Wiley & Sons Ltd.

  10. High-performance liquid chromatography of rat and mouse islet polypeptides

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    Linde, S; Hansen, B; Welinder, B S

    1990-01-01

    After preparative high-performance liquid chromatography of mouse islet culture medium, concentrated on disposable C18 cartridges (Sep-Pak), an unexpected insulin immunoreactive peak eluting earlier than mouse insulin I and II was detected. Molecular mass determination by mass spectrometry...... on the buffer, the organic modifier and the procedure. In particular the use of methanol-trifluoroacetic acid resulted in extensive oxidation. The oxidation could be minimized by adding 2 mM dithiothreitol to the buffer and by degassing and/or nitrogen-bubbling of the buffer. Minimal formation of Met...

  11. Lung-Derived Microscaffolds Facilitate Diabetes Reversal after Mouse and Human Intraperitoneal Islet Transplantation.

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    Abualhassan, Nasser; Sapozhnikov, Lena; Pawlick, Rena L; Kahana, Meygal; Pepper, Andrew R; Bruni, Antonio; Gala-Lopez, Boris; Kin, Tatsuya; Mitrani, Eduardo; Shapiro, A M James

    2016-01-01

    There is a need to develop three-dimensional structures that mimic the natural islet tissue microenvironment. Endocrine micro-pancreata (EMPs) made up of acellular organ-derived micro-scaffolds seeded with human islets have been shown to express high levels of key beta-cell specific genes and secrete quantities of insulin per cell similar to freshly isolated human islets in a glucose-regulated manner for more than three months in vitro. The aim of this study was to investigate the capacity of EMPs to restore euglycemia in vivo after transplantation of mouse or human islets in chemically diabetic mice. We proposed that the organ-derived EMPs would restore the extracellular components of the islet microenvironment, generating favorable conditions for islet function and survival. EMPs seeded with 500 mouse islets were implanted intraperitoneally into streptozotocin-induced diabetic mice and reverted diabetes in 67% of mice compared to 13% of controls (p = 0.018, n = 9 per group). Histological analysis of the explanted grafts 60 days post-transplantation stained positive for insulin and exhibited increased vascular density in a collagen-rich background. EMPs were also seeded with human islets and transplanted into the peritoneal cavity of immune-deficient diabetic mice at 250 islet equivalents (IEQ), 500 IEQ and 1000 IEQ. Escalating islet dose increased rates of normoglycemia (50% of the 500 IEQ group and 75% of the 1000 IEQ group, n = 3 per group). Human c-peptide levels were detected 90 days post-transplantation in a dose-response relationship. Herein, we report reversal of diabetes in mice by intraperitoneal transplantation of human islet seeded on EMPs with a human islet dose as low as 500 IEQ.

  12. L-leucine methyl ester stimulates insulin secretion and islet glutamate dehydrogenase

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    Knudsen, P; Kofod, Hans; Lernmark, A

    1983-01-01

    Column perifusion of collagenase-isolated mouse pancreatic islets was used to study the dynamics of insulin release in experiments lasting for several hours. The methyl esters of L-leucine and L-arginine were synthesized. Whereas L-arginine methyl ester (L-arginine OMe) had no effect, L-leucine OMe...... stimulated the release of insulin. The effect of L-leucine OMe was maximal at 5 mmol/liter. Whereas the Km for glucose-stimulated insulin release was unaffected by 1 mmol/liter L-leucine OMe, the maximal release of D-glucose was increased by the amino acid derivative that appeared more effective than L......-leucine. L-Leucine OMe was also a potent stimulus of insulin release from the perfused mouse pancreas. In the presence of 10 mmol/liter L-glutamine, 1 mmol/liter L-leucine OMe induced a 50- to 75-fold increase in insulin release. A similar stimulatory effect was also observed in column-perifused RIN 5F cells...

  13. Possible modulatory effect of endogenous islet catecholamines on insulin secretion

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    Gagliardino Juan J

    2001-10-01

    Full Text Available Abstract Background The possible participation of endogenous islet catecholamines (CAs in the control of insulin secretion was tested. Methods Glucose-induced insulin secretion was measured in the presence of 3-Iodo-L-Tyrosine (MIT, a specific inhibitor of tyrosine-hydroxylase activity, in fresh and precultured islets isolated from normal rats. Incubated islets were also used to measure CAs release in the presence of low and high glucose, and the effect of α2-(yohimbine [Y] and idazoxan [I] and α1-adrenergic antagonists (prazosin [P] and terazosin [T] upon insulin secretion elicited by high glucose. Results Fresh islets incubated with 16.7 mM glucose released significantly more insulin in the presence of 1 μM MIT (6.66 ± 0.39 vs 5.01 ± 0.43 ng/islet/h, p Conclusion Our results suggest that islet-originated CAs directly modulate insulin release in a paracrine manner.

  14. The effect of curcumin on insulin release in rat-isolated pancreatic islets.

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    Abdel Aziz, Mohamed T; El-Asmar, Mohamed F; El Nadi, Essam G; Wassef, Mohamed A; Ahmed, Hanan H; Rashed, Laila A; Obaia, Eman M; Sabry, Dina; Hassouna, Amira A; Abdel Aziz, Ahmed T

    2010-08-01

    Curcumin exerts a hypoglycemic action and induces heme-oxygenase-1 (HO-1). We evaluated the effect of curcumin on isolated islets of Langerhans and studied whether its action on insulin secretion is mediated by inducible HO-1. Islets were isolated from rats and divided into control islets, islets incubated in different curcumin concentrations, islets incubated in hemin, islets incubated in curcumin and HO inhibitor, stannous mesoporphyrin (SnMP), islets incubated in hemin and SnMP, islets incubated in SnMP only, and islets incubated in 16.7 mmol/L glucose. Heme-oxygenase activity, HO-1 expression, and insulin estimation was assessed. Insulin secretion, HO-1 gene expression and HO activity were significantly increased in islets incubated in curcumin, hemin, and glucose compared with controls. This increase in insulin secretion was significantly decreased by incubation of islets in SnMP. The action of curcumin on insulin secretion from the isolated islets may be, in part, mediated through increased HO-1 gene expression.

  15. The voltage-gated proton channel Hv1 is expressed in pancreatic islet β-cells and regulates insulin secretion

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    Zhao, Qing [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China); Che, Yongzhe [School of Medicine, Nankai University, Tianjin 300071 (China); Li, Qiang; Zhang, Shangrong [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China); Gao, Ying-Tang [Key Laboratory of Artificial Cell, Third Central Clinical College of Tianjin Medical University, Tianjin 300170 (China); Wang, Yifan; Wang, Xudong; Xi, Wang; Zuo, Weiyan [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China); Li, Shu Jie, E-mail: shujieli@nankai.edu.cn [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China)

    2015-12-25

    The voltage-gated proton channel Hv1 is a potent acid extruder that participates in the extrusion of the intracellular acid. Here, we showed for the first time, Hv1 is highly expressed in mouse and human pancreatic islet β-cells, as well as β-cell lines. Imaging studies demonstrated that Hv1 resides in insulin-containing granules in β-cells. Knockdown of Hv1 with RNA interference significantly reduces glucose- and K{sup +}-induced insulin secretion in isolated islets and INS-1 (832/13) β-cells and has an impairment on glucose- and K{sup +}-induced intracellular Ca{sup 2+} homeostasis. Our data demonstrated that the expression of Hv1 in pancreatic islet β-cells regulates insulin secretion through regulating Ca{sup 2+} homeostasis.

  16. Islet oxygen consumption rate (OCR) dose predicts insulin independence for first clinical islet allotransplants

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    Kitzmann, JP; O’Gorman, D; Kin, T; Gruessner, AC; Senior, P; Imes, S; Gruessner, RW; Shapiro, AMJ; Papas, KK

    2014-01-01

    Human islet allotransplant (ITx) for the treatment of type 1 diabetes is in phase III clinical registration trials in the US and standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose stimulated insulin release (GSIR), and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following one transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models. In this paper we report on the assessment of clinical islet allograft preparations using islet oxygen consumption rate (OCR) dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant. Results showed that OCR dose was most predictive of CTO. IE dose was also highly predictive, while GSIR and membrane integrity stains were not. In conclusion, OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical ITx. PMID:25131089

  17. Intra- and Inter-islet Synchronization of Metabolically Driven Insulin Secretion

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    Pedersen, Morten Gram; Bertram, Richard; Sherman, Arthur

    2005-01-01

    mechanisms for intra-islet and inter-islet synchronization. We show that electrical coupling is sufficient to synchronize both electrical bursting activity and metabolic oscillations. We also demonstrate that islets can synchronize by mutually entraining each other by their effects on a simple model "liver......,'' which responds to the level of insulin secretion by adjusting the blood glucose concentration in an appropriate way. Since all islets are exposed to the blood, the distributed islet-liver system can synchronize the individual islet insulin oscillations. Thus, we demonstrate how intra-islet and inter...

  18. Immunohistochemical expression of insulin, glucagon, and somatostatin in pancreatic islets of horses with and without insulin resistance.

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    Newkirk, Kim M; Ehrensing, Gordon; Odoi, Agricola; Boston, Raymond C; Frank, Nicholas

    2018-02-01

    OBJECTIVE To assess insulin, glucagon, and somatostatin expression within pancreatic islets of horses with and without insulin resistance. ANIMALS 10 insulin-resistant horses and 13 insulin-sensitive horses. PROCEDURES For each horse, food was withheld for at least 10 hours before a blood sample was collected for determination of serum insulin concentration. Horses with a serum insulin concentration horses with a serum insulin concentration > 20 μU/mL underwent a frequently sampled IV glucose tolerance test to determine sensitivity to insulin by minimal model analysis. Horses with a sensitivity to insulin horses were euthanized with a barbiturate overdose, and pancreatic specimens were harvested and immunohistochemically stained for determination of insulin, glucagon, and somatostatin expression in pancreatic islets. Islet hormone expression was compared between insulin-resistant and insulin-sensitive horses. RESULTS Cells expressing insulin, glucagon, and somatostatin made up approximately 62%, 12%, and 7%, respectively, of pancreatic islet cells in insulin-resistant horses and 64%, 18%, and 9%, respectively, of pancreatic islet cells in insulin-sensitive horses. Expression of insulin and somatostatin did not differ between insulin-resistant and insulin-sensitive horses, but the median percentage of glucagon-expressing cells in the islets of insulin-resistant horses was significantly less than that in insulin-sensitive horses. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that, in insulin-resistant horses, insulin secretion was not increased but glucagon production might be downregulated as a compensatory response to hyperinsulinemia.

  19. Generation of glucose-responsive functional islets with a three-dimensional structure from mouse fetal pancreatic cells and iPS cells in vitro.

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    Hiroki Saito

    Full Text Available Islets of Langerhans are a pancreatic endocrine compartment consisting of insulin-producing β cells together with several other hormone-producing cells. While some insulin-producing cells or immature pancreatic cells have been generated in vitro from ES and iPS cells, islets with proper functions and a three-dimensional (3D structure have never been successfully produced. To test whether islets can be formed in vitro, we first examined the potential of mouse fetal pancreatic cells. We found that E16.5 pancreatic cells, just before forming islets, were able to develop cell aggregates consisting of β cells surrounded by glucagon-producing α cells, a structure similar to murine adult islets. Moreover, the transplantation of these cells improved blood glucose levels in hyperglycemic mice. These results indicate that functional islets are formed in vitro from fetal pancreatic cells at a specific developmental stage. By adopting these culture conditions to the differentiation of mouse iPS cells, we developed a two-step system to generate islets, i.e. immature pancreatic cells were first produced from iPS cells, and then transferred to culture conditions that allowed the formation of islets from fetal pancreatic cells. The islets exhibited distinct 3D structural features similar to adult pancreatic islets and secreted insulin in response to glucose concentrations. Transplantation of the islets improved blood glucose levels in hyperglycemic mice. In conclusion, the two-step culture system allows the generation of functional islets with a 3D structure from iPS cells.

  20. Transplanted human pancreatic islets after long-term insulin independence

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    Muller, Y D; Gupta, Shashank; Morel, P

    2013-01-01

    Long-term insulin independence after islets of Langerhans transplantation is rarely achieved. The aims of this study were to identify the histological and immunological features of islets transplanted in a type 1 diabetic patient who died of a cerebral hemorrhage after >13 years insulin independe...

  1. Ancestral genomic duplication of the insulin gene in tilapia: An analysis of possible implications for clinical islet xenotransplantation using donor islets from transgenic tilapia expressing a humanized insulin gene.

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    Hrytsenko, Olga; Pohajdak, Bill; Wright, James R

    2016-07-03

    Tilapia, a teleost fish, have multiple large anatomically discrete islets which are easy to harvest, and when transplanted into diabetic murine recipients, provide normoglycemia and mammalian-like glucose tolerance profiles. Tilapia insulin differs structurally from human insulin which could preclude their use as islet donors for xenotransplantation. Therefore, we produced transgenic tilapia with islets expressing a humanized insulin gene. It is now known that fish genomes may possess an ancestral duplication and so tilapia may have a second insulin gene. Therefore, we cloned, sequenced, and characterized the tilapia insulin 2 transcript and found that its expression is negligible in islets, is not islet-specific, and would not likely need to be silenced in our transgenic fish.

  2. Insulin secretion and glucose uptake by isolated islets of the hamster. Effect of insulin, proinsulin and C-peptide

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    Dunbar, J C; McLaughlin, W J; Walsh, M F.J.; Foa, P P [Sinai Hospital of Detroit, Mich. (USA). Dept. of Research

    1976-01-01

    Isolated pancreatic islets of normal hamsters were perfused either in a closed or in a open system. When the buffer was recirculated and the endogenous insulin was allowed to accumulate, the islets secreted significantly less insulin than when the system was open and the endogenous insulin was washed away. The addition of monocomponent insulin or of proinsulin to the perfusion buffer significantly decreased insulin secretion. The inhibitory action of proinsulin was significantly greater than that of monocomponent insulin. C peptide had no effect. When pancreatic islets were incubated in a fixed volume of stationary buffer containing unlabeled glucose (1.0 mg or 3.0 mg/ml) and glucose-U-/sup 14/C (1.0 ..mu..C/ml), the amount of insulin secreted and the /sup 14/CO/sub 2/ produced by each islet decreased progressively as the number of islets in the sample increased. Under these conditions, the concentration of insulin required to inhibit insulin secretion increased with the concentration of glucose in the medium. Proinsulin did not alter the incorporation of leucine-4.5-/sup 3/H into total extractable insulin (insulin + proinsulin). Thus, insulin and proinsulin appear to inhibit insulin release, but not insulin synthesis.

  3. Insulin resistance alters islet morphology in nondiabetic humans

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    Mezza, Teresa; Muscogiuri, Giovanna; Sorice, Gian Pio

    2014-01-01

    Type 2 diabetes is characterized by poor glucose uptake in metabolic tissues and manifests when insulin secretion fails to cope with worsening insulin resistance. In addition to its effects on skeletal muscle, liver, and adipose tissue metabolism, it is evident that insulin resistance also affects...... pancreatic β-cells. To directly examine the alterations that occur in islet morphology as part of an adaptive mechanism to insulin resistance, we evaluated pancreas samples obtained during pancreatoduodenectomy from nondiabetic subjects who were insulin-resistant or insulin-sensitive. We also compared...... insulin sensitivity, insulin secretion, and incretin levels between the two groups. We report an increased islet size and an elevated number of β- and α-cells that resulted in an altered β-cell-to-α-cell area in the insulin- resistant group. Our data in this series of studies suggest that neogenesis from...

  4. Abnormal infant islet morphology precedes insulin resistance in PCOS-like monkeys.

    Directory of Open Access Journals (Sweden)

    Lindsey E Nicol

    Full Text Available Polycystic ovary syndrome (PCOS is prevalent in reproductive-aged women and confounded by metabolic morbidities, including insulin resistance and type 2 diabetes. Although the etiology of PCOS is undefined, contribution of prenatal androgen (PA exposure has been proposed in a rhesus monkey model as premenopausal PA female adults have PCOS-like phenotypes in addition to insulin resistance and decreased glucose tolerance. PA female infants exhibit relative hyperinsulinemia, suggesting prenatal sequelae of androgen excess on glucose metabolism and an antecedent to future metabolic disease. We assessed consequences of PA exposure on pancreatic islet morphology to identify evidence of programming on islet development. Islet counts and size were quantified and correlated with data from intravenous glucose tolerance tests (ivGTT obtained from dams and their offspring. Average islet size was decreased in PA female infants along with corresponding increases in islet number, while islet fractional area was preserved. Infants also demonstrated an increase in both the proliferation marker Ki67 within islets and the beta to alpha cell ratio suggestive of enhanced beta cell expansion. PA adult females have reduced proportion of small islets without changes in proliferative or apoptotic markers, or in beta to alpha cell ratios. Together, these data suggest in utero androgen excess combined with mild maternal glucose intolerance alter infant and adult islet morphology, implicating deviant islet development. Marked infant, but subtle adult, morphological differences provide evidence of islet post-natal plasticity in adapting to changing physiologic demands: from insulin sensitivity and relative hypersecretion to insulin resistance and diminished insulin response to glucose in the mature PCOS-like phenotype.

  5. Factors influencing insulin secretion from encapsulated islets

    NARCIS (Netherlands)

    de Haan, BJ; Faas, MM; de Vos, P

    2003-01-01

    Adequate regulation of glucose levels by a microencapsulated pancreatic islet graft requires a minute-to-minute regulation of blood glucose. To design such a transplant, it is mandatory to have sufficient insight in factors influencing the kinetics of insulin secretion by encapsulated islets. The

  6. Potentiation of insulin release in response to amino acid methyl esters correlates to activation of islet glutamate dehydrogenase activity

    DEFF Research Database (Denmark)

    Kofod, Hans; Lernmark, A; Hedeskov, C J

    1986-01-01

    Column perifusion of mouse pancreatic islets was used to study the ability of amino acids and their methyl esters to influence insulin release and activate islet glutamate dehydrogenase activity. In the absence of L-glutamine, L-serine and the methyl ester of L-phenylalanine, but neither L...... glutamate dehydrogenase activity showed that only the two methyl esters of L-phenylalanine and L-serine activated the enzyme. It is concluded that the mechanism by which methyl esters of amino acids potentiate insulin release is most likely to be mediated by the activation of pancreatic beta-cell glutamate...

  7. 65Zinc and endogenous zinc content and distribution in islets in relationship to insulin content

    International Nuclear Information System (INIS)

    Figlewicz, D.P.; Forhan, S.E.; Hodgson, A.T.; Grodsky, G.M.

    1984-01-01

    Uptake of 65 Zn and distribution of 65 Zn, total zinc, and insulin were measured in rat islets and islet granules under different conditions of islet culture. Specific activity of islet zinc ( 65 Zn/zinc) was less than 15% that of extracellular zinc even after 48 h. In contrast, once in the islet, 65 Zn approached 70% of equilibrium with granular zinc in 24 h and apparent equilibrium by 48 h. During a 24-h culture, at either high or low glucose, reduction of both islet zinc and insulin occurred. However, zinc depletion was greater than that predicted if zinc loss was proportional to insulin depletion and occurred only from the granular compartment, which represents only one third of the total islet zinc. Extension of culture to 48 h caused additional insulin depletion, but islet zinc was unchanged. Omission of calcium during the 48-h culture caused a predicted increase in insulin retention, presumably by inhibiting secretion; however, zinc retention was not increased proportionately. Pretreatment of rats with tolbutamide caused a massive depletion of insulin stored in isolated islets, with little change in total islet zinc; subsequent culture of these islets resulted in a greater loss of granular zinc than predicted from the small loss of granular insulin. None of the conditions tested affected the percentage of either 65 Zn or total zinc that was distributed in the islet granules. Results show that zinc exists in a metabolically labile islet compartment(s) as well as in secretory granules; and extra-granular zinc, although not directly associated with insulin storage, may act as a reservoir for granular zinc and may regulate insulin synthesis, storage, and secretion in ways as yet unknown

  8. Exercise Increases Insulin Content and Basal Secretion in Pancreatic Islets in Type 1 Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Han-Hung Huang

    2011-01-01

    Full Text Available Exercise appears to improve glycemic control for people with type 1 diabetes (T1D. However, the mechanism responsible for this improvement is unknown. We hypothesized that exercise has a direct effect on the insulin-producing islets. Eight-week-old mice were divided into four groups: sedentary diabetic, exercised diabetic, sedentary control, and exercised control. The exercised groups participated in voluntary wheel running for 6 weeks. When compared to the control groups, the islet density, islet diameter, and β-cell proportion per islet were significantly lower in both sedentary and exercised diabetic groups and these alterations were not improved with exercise. The total insulin content and insulin secretion were significantly lower in sedentary diabetics compared to controls. Exercise significantly improved insulin content and insulin secretion in islets in basal conditions. Thus, some improvements in exercise-induced glycemic control in T1D mice may be due to enhancement of insulin content and secretion in islets.

  9. Decrease of glucose-induced insulin secretion of rat pancreatic islets after irradiation in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Heinzmann, D; Nadrowitz, R; Besch, W; Schmidt, W; Hahn, H J [Zentralinstitut fuer Diabetes, Karlsburg (German Democratic Republic); Ernst-Moritz-Arndt-Universitaet, Greifswald (German Democratic Republic). Radiologische Klinik)

    1983-01-01

    In vitro irradiation of rat pancreatic islets up to a dose of 2.5 Gy did neither alter glucose- nor isobutylmethyl xanthine (IBMX)-induced insulin secretion. Insulin as well as glucagon content of irradiated islets corresponded to that of the control tissue. So it was in islets irradiated with 25 Gy which were characterized by a decreased insulin secretion in the presence of glucose and IBMX, respectively. There was no indication of an enhanced hormone output in the radiation medium and it is to be suggested that higher radiation doses affect the insulin release of pancreatic islets in vitro. This must be taken into consideration for radioimmunosuppression experiments.

  10. Single-donor islet transplantation and long-term insulin independence in select patients with type 1 diabetes mellitus.

    Science.gov (United States)

    Al-Adra, David P; Gill, Richdeep S; Imes, Sharleen; O'Gorman, Doug; Kin, Tatsuya; Axford, Sara J; Shi, Xinzhe; Senior, Peter A; Shapiro, A M James

    2014-11-15

    Islet transplantation is a recognized treatment option for select patients with type I diabetes mellitus. However, islet infusions from multiple donors are often required to achieve insulin independence. Ideally, insulin independence would be achieved routinely with only a single donor. Identification of factors associated with insulin independence after single-donor islet transplantation may help to select recipient-donor combinations with the highest probability of success. Subjects undergoing islet transplantation at a single center (Edmonton, Canada) between March 1999 and August 2013 were included. Recipient, donor, and transplant characteristics were collected and compared between recipients who became insulin independent after one islet transplantation and those who did not. Thirty-one patients achieved insulin independence after a single-donor islet transplantation, and 149 did not. Long-term insulin-free survival was not different between the groups. Factors significantly associated with single-donor success included recipient age, insulin requirement at baseline, donor weight, donor body mass index, islet transplant mass, and peritransplant heparin and insulin administration. On multivariate analysis, pretransplantation daily insulin requirements, the use of peritransplantation heparin and insulin infusions, and islet transplant mass remained significant. We have identified clinically relevant differences defining the achievement of insulin independence after single-donor transplantation. Based on these differences, a preoperative insulin requirement of less than 0.6 U/kg per day and receiving more than 5,646 islet equivalents (IEQ)/kg have a sensitivity of 84% and 71% and specificity of 50% and 50%, respectively, for insulin independence after single-donor islet transplantation. With ideal patient selection, this finding could potentially increase single-donor transplantation success and may be especially relevant for presensitized subjects or those who

  11. Dissociation between insulin secretion and DNA synthesis in cultured pancreatic islets

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    1985-01-01

    -Tdr incorporation. However, long-term exposure to IBMX did not result in increased DNA content of the islets. Inhibition of the DNA synthesis by 5 mM hydroxyurea resulted in a marked reduction in DNA content of the islets but no decrease in either insulin release or insulin content when expressed per ng DNA...

  12. Integrative analysis of a cross-loci regulation network identifies App as a gene regulating insulin secretion from pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Zhidong Tu

    Full Text Available Complex diseases result from molecular changes induced by multiple genetic factors and the environment. To derive a systems view of how genetic loci interact in the context of tissue-specific molecular networks, we constructed an F2 intercross comprised of >500 mice from diabetes-resistant (B6 and diabetes-susceptible (BTBR mouse strains made genetically obese by the Leptin(ob/ob mutation (Lep(ob. High-density genotypes, diabetes-related clinical traits, and whole-transcriptome expression profiling in five tissues (white adipose, liver, pancreatic islets, hypothalamus, and gastrocnemius muscle were determined for all mice. We performed an integrative analysis to investigate the inter-relationship among genetic factors, expression traits, and plasma insulin, a hallmark diabetes trait. Among five tissues under study, there are extensive protein-protein interactions between genes responding to different loci in adipose and pancreatic islets that potentially jointly participated in the regulation of plasma insulin. We developed a novel ranking scheme based on cross-loci protein-protein network topology and gene expression to assess each gene's potential to regulate plasma insulin. Unique candidate genes were identified in adipose tissue and islets. In islets, the Alzheimer's gene App was identified as a top candidate regulator. Islets from 17-week-old, but not 10-week-old, App knockout mice showed increased insulin secretion in response to glucose or a membrane-permeant cAMP analog, in agreement with the predictions of the network model. Our result provides a novel hypothesis on the mechanism for the connection between two aging-related diseases: Alzheimer's disease and type 2 diabetes.

  13. Urea impairs β cell glycolysis and insulin secretion in chronic kidney disease

    Science.gov (United States)

    Koppe, Laetitia; Nyam, Elsa; Vivot, Kevin; Manning Fox, Jocelyn E.; Dai, Xiao-Qing; Nguyen, Bich N.; Attané, Camille; Moullé, Valentine S.; MacDonald, Patrick E.; Ghislain, Julien

    2016-01-01

    Disorders of glucose homeostasis are common in chronic kidney disease (CKD) and are associated with increased mortality, but the mechanisms of impaired insulin secretion in this disease remain unclear. Here, we tested the hypothesis that defective insulin secretion in CKD is caused by a direct effect of urea on pancreatic β cells. In a murine model in which CKD is induced by 5/6 nephrectomy (CKD mice), we observed defects in glucose-stimulated insulin secretion in vivo and in isolated islets. Similarly, insulin secretion was impaired in normal mouse and human islets that were cultured with disease-relevant concentrations of urea and in islets from normal mice treated orally with urea for 3 weeks. In CKD mouse islets as well as urea-exposed normal islets, we observed an increase in oxidative stress and protein O-GlcNAcylation. Protein O-GlcNAcylation was also observed in pancreatic sections from CKD patients. Impairment of insulin secretion in both CKD mouse and urea-exposed islets was associated with reduced glucose utilization and activity of phosphofructokinase 1 (PFK-1), which could be reversed by inhibiting O-GlcNAcylation. Inhibition of O-GlcNAcylation also restored insulin secretion in both mouse models. These results suggest that insulin secretory defects associated with CKD arise from elevated circulating levels of urea that increase islet protein O-GlcNAcylation and impair glycolysis. PMID:27525435

  14. Decrease of glucose-induced insulin secretion of pancreatic rat islets after irradiation in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Heinzmann, D; Nadrowitz, R; Besch, W; Schmidt, W; Hahn, H J

    1983-01-01

    Irradiation of pancreatic rat islets up to a dose of 2.5 Gy did neither alter glucose-nor IBMX-induced insulin secretion studied in vitro. The insulin as well as glucagon content of irradiated islets were similar as in the control tissue. This was also true in islets irradiated with 25 Gy which were characterized by a decreased insulin secretion in the presence of glucose and IBMX, respectively. Since we did not find indications of an enhanced hormone output in the radiation medium, we want to suggest that higher irradiation doses affect insulin release of pancreatic islets in vitro. This observation has to be taken into account for application of radioimmunosuppression for transplantation.

  15. Heterogeneity and compartmental properties of insulin storage and secretion in rat islets

    International Nuclear Information System (INIS)

    Gold, G.; Landahl, H.D.; Gishizky, M.L.; Grodsky, G.M.

    1982-01-01

    To investigate compartmental properties of insulin storage and secretion, isolated rat islets were used for pulse-labeling experiments, after which proinsulin and insulin were purified rigorously. Processing of proinsulin to insulin neared completion by 3 h without additional loss of either radioactive peptide by cellular or extracellular proteolysis. The amount of labeled hormone rapidly diminished in islets; it was secreted at a higher fractional rate than immunoreactive insulin, resulting in secreted insulin's having a higher specific activity than the average cellular insulin. Newly synthesized insulin, therefore, was secreted preferentially. Changes in the specific activity of secreted and cellular insulin with time were consistent with changes predicted for islets containing 33% of their total insulin in a glucose-labile compartment. Predictions were based on steady-state analysis of a simple storage-limited representation of B cell function. Islets from either the dorsal or ventral part of the pancreas also contained 33% of their total insulin in a glucose-labile compartment. The same compartment was mobilized by 20 mM glucose, 50 mM potassium + 2 mM glucose, or 20 MM glucose + 1 mM 3-isobutylmethylxanthine as indicated by the specific activity ratio of secreted vs. cellular insulin, even though average secretion rates with these stimuli differed by more than threefold. In the absence of calcium, the effectiveness of 20 mM glucose as a secretagogue declined markedly, and the older stored insulin was preferentially mobilized because secreted insulin had a lower rather than a higher specific activity than cellular insulin. Results provide insight into the mechanisms of nonrandom mobilization and secretion of insulin form the B cell

  16. Potentiation of glucose-induced insulin release in islets by desHis1[Glu9]glucagon amide

    DEFF Research Database (Denmark)

    Kofod, Hans; Unson, C G; Merrifield, R B

    1988-01-01

    Glucagon and secretin and some of their hybrid analogs potentiate glucose-induced release of insulin from isolated mouse pancreatic islets. It was recently shown that the synthetic glucagon analog, desHis1[Glu9]glucagon amide, does not stimulate the formation of cyclic adenosine monophosphate...... in the rat hepatocyte membrane, but binds well to the glucagon receptor and is a good competitive antagonist of glucagon. In the present study the effect of this analog on isolated islets was examined. desHis1-[Glu9]glucagon amide at 3 x 10(-7) M, in the presence of 0.01 M D-glucose, increased the release...

  17. Transfer plate radioassay using adsorbed anti-insulin antibody to detect insulin secreted by islet cell cultures

    International Nuclear Information System (INIS)

    Scearce, R.M.; Oie, H.K.; Gazdar, A.F.; Chick, W.L.; Eisenbarth, G.S.

    1981-01-01

    A solid-phase radioimmunoassay for detection of insulin synthesized by islet cell clones is described. This assay employs anti-insulin antibody adsorbed onto fenestrated polyvinyl chloride 96-well plates ('transfer plates'). The calibrated aperture in the bottom of each transfer plate well permits fluid to enter the wells when transfer plates are lowered into microculture wells containing insulin. With this assay it is possible to rapidly screen hundreds of islet cell cultures for insulin production. The authors have used this assay to facilitate cloning of the RIN rat insulinoma cell line. The assay readily detects insulin synthesis by RIN cells and [ 125 I]insulin is not displaced by culture medium from cells which do not produce insulin. The transfer plate format should be applicable to semiautomate other radioimmunoassays. (Auth.)

  18. Differences in glucose-stimulated insulin secretion in vitro of islets from human, nonhuman primate, and porcine origin.

    Science.gov (United States)

    Mueller, Kate R; Balamurugan, A N; Cline, Gary W; Pongratz, Rebecca L; Hooper, Rebecca L; Weegman, Bradley P; Kitzmann, Jennifer P; Taylor, Michael J; Graham, Melanie L; Schuurman, Henk-Jan; Papas, Klearchos K

    2013-01-01

    Porcine islet xenotransplantation is considered a potential cell-based therapy for type 1 diabetes. It is currently being evaluated in diabetic nonhuman primates (NHP) to assess safety and efficacy of the islet product. However, due to a variety of distinct differences between the respective species, including the insulin secretory characteristics of islets, the suitability and predictive value of the preclinical model in the extrapolation to the clinical setting remain a critical issue. Islets isolated from human (n = 3), NHP (n = 2), adult pig (AP, n = 3), and juvenile pig (JP, n = 4) pancreata were perifused with medium at basal glucose (2.5 mm) followed by high glucose (16.7 mm) concentrations. The total glucose-stimulated insulin secretion (GSIS) was calculated from generated insulin secretion profiles. Nonhuman primate islets exhibited GSIS 3-fold higher than AP islets, while AP and JP islets exhibited GSIS 1/3 and 1/30 of human islets, respectively. The insulin content of NHP and AP islets was similar to that of human islets, whereas that of JP islets was 1/5 of human islets. Despite the fact that human, NHP, and AP islets contain similar amounts of insulin, the much higher GSIS for NHP islets than for AP and JP islets suggests the need for increased dosing of islets from JP and AP in pig-to-NHP transplantation. Porcine islet xenotransplantation to humans may require significantly higher dosing given the lower GSIS of AP islets compared to human islets. © 2013 John Wiley & Sons A/S.

  19. Glucose triggers protein kinase A-dependent insulin secretion in mouse pancreatic islets through activation of the K+ATP channel-dependent pathway

    DEFF Research Database (Denmark)

    Thams, Peter; Anwar, Mohammad R; Capito, Kirsten

    2005-01-01

    pancreatic islets was determined by radioimmunoassay. RESULTS: In islets cultured at 5.5 mmol/l glucose, and then perifused in physiological Krebs-Ringer medium, the PKA inhibitors, H89 (10 micromol/l) and PKI 6-22 amide (30 micromol/l) did not inhibit glucose (16.7 mmol/l)-induced insulin secretion...

  20. Delta-like Ligand-4-Notch Signaling Inhibition Regulates Pancreatic Islet Function and Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Fabienne Billiard

    2018-01-01

    Full Text Available Although Notch signaling has been proposed as a therapeutic target for type-2 diabetes, liver steatosis, and atherosclerosis, its direct effect on pancreatic islets remains unknown. Here, we demonstrated a function of Dll4-Notch signaling inhibition on the biology of insulin-producing cells. We confirmed enhanced expression of key Notch signaling genes in purified pancreatic islets from diabetic NOD mice and showed that treatment with anti-Dll4 antibody specifically abolished Notch signaling pathway activation. Furthermore, we showed that Notch inhibition could drive proliferation of β-islet cells and confer protection from the development of STZ-induced diabetes. Importantly, inhibition of the Dll4 pathway in WT mice increased insulin secretion by inducing the differentiation of pancreatic β-islet cell progenitors, as well as the proliferation of insulin-secreting cells. These findings reveal a direct effect of Dll4-blockade on pancreatic islets that, in conjunction with its immunomodulatory effects, could be used for unmet medical needs hallmarked by inefficient insulin action.

  1. Opiate-prostaglandin interactions in the regulation of insulin secretion from rat islets of Langerhans in vitro

    International Nuclear Information System (INIS)

    Green, I.C.; Tadayyon, M.

    1988-01-01

    The inadequate insulin secretory response to glucose stimulation in non-insulin dependent diabetes has been attributed to many factors including high PGE 2 levels blunting the secretory response, and to the existence of inhibitory opiate activity in vivo. The purpose of the present work was to see if there was a connection between these two independent theories. Radioimmunoassayable PGE 2 in islets of Langerhans was found to be proportional to islet number and protein content and was typically 4 to 5pg/μg islet protein. Indomethacin sodium salicylate and chlorpropamide all lowered islet PGE 2 levels and stimulated insulin release in vitro. Dynorphin stimulated insulin release at a concentration of 6 x 10 -9 M, while lowering islet PGE 2 . Conversely, at a higher concentration, dynorphin had no stimulatory effect on insulin secretion and did not lower PGE 2 levels in islets or in the incubation media. The stimulatory effects of dynorphin and sodium salicylate on insulin secretion were blocked by exogenous PGE 2 . PGE 2 at a lower concentration did not exert any inhibitory effect on dynorphin- or sodium salicylate-induced insulin release. This concentration of exogenous PGE 2 stimulated insulin release in the presence of 6mM glucose

  2. Stress-induced dissociations between intracellular calcium signaling and insulin secretion in pancreatic islets.

    Science.gov (United States)

    Qureshi, Farhan M; Dejene, Eden A; Corbin, Kathryn L; Nunemaker, Craig S

    2015-05-01

    In healthy pancreatic islets, glucose-stimulated changes in intracellular calcium ([Ca(2+)]i) provide a reasonable reflection of the patterns and relative amounts of insulin secretion. We report that [Ca(2+)]i in islets under stress, however, dissociates with insulin release in different ways for different stressors. Islets were exposed for 48h to a variety of stressors: cytokines (low-grade inflammation), 28mM glucose (28G, glucotoxicity), free fatty acids (FFAs, lipotoxicity), thapsigargin (ER stress), or rotenone (mitochondrial stress). We then measured [Ca(2+)]i and insulin release in parallel studies. Islets exposed to all stressors except rotenone displayed significantly elevated [Ca(2+)]i in low glucose, however, increased insulin secretion was only observed for 28G due to increased nifedipine-sensitive calcium-channel flux. Following 3-11mM glucose stimulation, all stressors substantially reduced the peak glucose-stimulated [Ca(2+)]i response (first phase). Thapsigargin and cytokines also substantially impacted aspects of calcium influx and ER calcium handling. Stressors did not significantly impact insulin secretion in 11mM glucose for any stressor, although FFAs showed a borderline reduction, which contributed to a significant decrease in the stimulation index (11:3mM glucose) observed for FFAs and also for 28G. We also clamped [Ca(2+)]i using 30mM KCl+250μM diazoxide to test the amplifying pathway. Only rotenone-treated islets showed a robust increase in 3-11mM glucose-stimulated insulin secretion under clamped conditions, suggesting that low-level mitochondrial stress might activate the metabolic amplifying pathway. We conclude that different stressors dissociate [Ca(2+)]i from insulin secretion differently: ER stressors (thapsigargin, cytokines) primarily affect [Ca(2+)]i but not conventional insulin secretion and 'metabolic' stressors (FFAs, 28G, rotenone) impacted insulin secretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Survival of Free and Encapsulated Human and Rat Islet Xenografts Transplanted into the Mouse Bone Marrow

    Science.gov (United States)

    Meier, Raphael P. H.; Seebach, Jörg D.; Morel, Philippe; Mahou, Redouan; Borot, Sophie; Giovannoni, Laurianne; Parnaud, Geraldine; Montanari, Elisa; Bosco, Domenico; Wandrey, Christine; Berney, Thierry; Bühler, Leo H.; Muller, Yannick D.

    2014-01-01

    Bone marrow was recently proposed as an alternative and potentially immune-privileged site for pancreatic islet transplantation. The aim of the present study was to assess the survival and rejection mechanisms of free and encapsulated xenogeneic islets transplanted into the medullary cavity of the femur, or under the kidney capsule of streptozotocin-induced diabetic C57BL/6 mice. The median survival of free rat islets transplanted into the bone marrow or under the kidney capsule was 9 and 14 days, respectively, whereas that of free human islets was shorter, 7 days (bone marrow) and 10 days (kidney capsule). Infiltrating CD8+ T cells and redistributed CD4+ T cells, and macrophages were detected around the transplanted islets in bone sections. Recipient mouse splenocytes proliferated in response to donor rat stimulator cells. One month after transplantation under both kidney capsule or into bone marrow, encapsulated rat islets had induced a similar degree of fibrotic reaction and still contained insulin positive cells. In conclusion, we successfully established a small animal model for xenogeneic islet transplantation into the bone marrow. The rejection of xenogeneic islets was associated with local and systemic T cell responses and macrophage recruitment. Although there was no evidence for immune-privilege, the bone marrow may represent a feasible site for encapsulated xenogeneic islet transplantation. PMID:24625569

  4. Survival of free and encapsulated human and rat islet xenografts transplanted into the mouse bone marrow.

    Directory of Open Access Journals (Sweden)

    Raphael P H Meier

    Full Text Available Bone marrow was recently proposed as an alternative and potentially immune-privileged site for pancreatic islet transplantation. The aim of the present study was to assess the survival and rejection mechanisms of free and encapsulated xenogeneic islets transplanted into the medullary cavity of the femur, or under the kidney capsule of streptozotocin-induced diabetic C57BL/6 mice. The median survival of free rat islets transplanted into the bone marrow or under the kidney capsule was 9 and 14 days, respectively, whereas that of free human islets was shorter, 7 days (bone marrow and 10 days (kidney capsule. Infiltrating CD8+ T cells and redistributed CD4+ T cells, and macrophages were detected around the transplanted islets in bone sections. Recipient mouse splenocytes proliferated in response to donor rat stimulator cells. One month after transplantation under both kidney capsule or into bone marrow, encapsulated rat islets had induced a similar degree of fibrotic reaction and still contained insulin positive cells. In conclusion, we successfully established a small animal model for xenogeneic islet transplantation into the bone marrow. The rejection of xenogeneic islets was associated with local and systemic T cell responses and macrophage recruitment. Although there was no evidence for immune-privilege, the bone marrow may represent a feasible site for encapsulated xenogeneic islet transplantation.

  5. Release of immunoreactive and radioactively prelabelled endogenous (pro-)insulin from isolated islets of rat pancreas in the presence of exogenous insulin

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, H [Giessen Univ. (Germany, F.R.). Zentrum fuer Innere Medizin; Pfeiffer, E F

    1977-01-01

    To study the influence of insulin on its secretion, collagenase-isolated islets of rat pancreas were prelabelled with (/sup 3/H)leucine for 2 h. After washing the islets, (pro-)insulin release was stimulated by glucose in the presence or absence of exogenous insulin (up to 2.5 mu./ml. Hormone release was unchanged by the presence of exogenous insulin as judged by determination of both immunoreactive insulin and radioactivity incorporated into the proinsulin and insulin fractions of the medium. No direct feedback mechanism for insulin secretion was apparent from this study.

  6. Mesenchymal stromal cells improve human islet function through released products and extracellular matrix.

    Science.gov (United States)

    Arzouni, Ahmed A; Vargas-Seymour, Andreia; Rackham, Chloe L; Dhadda, Paramjeet; Huang, Guo-Cai; Choudhary, Pratik; Nardi, Nance; King, Aileen J F; Jones, Peter M

    2017-12-01

    The aims of the present study were (i) to determine whether the reported beneficial effects of mesenchymal stromal cells (MSCs) on mouse islet function extend to clinically relevant human tissues (islets and MSCs), enabling translation into improved protocols for clinical human islet transplantation; and (ii) to identify possible mechanisms through which human MSCs influence human islet function. Human islets were co-cultured with human adipose tissue-derived MSCs (hASCs) or pre-treated with its products - extracellular matrix (ECM) and annexin A1 (ANXA1). Mouse islets were pre-treated with mouse MSC-derived ECM. Islet insulin secretory function was assessed in vitro by radioimmunoassay. Quantitative RT-PCR was used to screen human adipMSCs for potential ligands of human islet G-protein-coupled receptors. We show that co-culture with hASCs improves human islet secretory function in vitro , as measured by glucose-stimulated insulin secretion, confirming previous reports using rodent tissues. Furthermore, we demonstrate that these beneficial effects on islet function can be partly attributed to the MSC-derived products ECM and ANXA1. Our results suggest that hASCs have the potential to improve the quality of human islets isolated for transplantation therapy of Type 1 diabetes. Furthermore, it may be possible to achieve improvements in human islet quality in a cell-free culture system by using the MSC-derived products ANXA1 and ECM. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  7. A Practical Guide to Rodent Islet Isolation and Assessment

    Directory of Open Access Journals (Sweden)

    Carter Jeffrey D

    2009-12-01

    Full Text Available Abstract Pancreatic islets of Langerhans secrete hormones that are vital to the regulation of blood glucose and are, therefore, a key focus of diabetes research. Purifying viable and functional islets from the pancreas for study is an intricate process. This review highlights the key elements involved with mouse and rat islet isolation, including choices of collagenase, the collagenase digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews commonly used techniques for assessing islet viability and function, including visual assessment, fluorescent markers of cell death, glucose-stimulated insulin secretion, and intracellular calcium measurements. A detailed protocol is also included that describes a common method for rodent islet isolation that our laboratory uses to obtain viable and functional mouse islets for in vitro study of islet function, beta-cell physiology, and in vivo rodent islet transplantation. The purpose of this review is to serve as a resource and foundation for successfully procuring and purifying high-quality islets for research purposes.

  8. Glucose Induces Mouse β-Cell Proliferation via IRS2, MTOR, and Cyclin D2 but Not the Insulin Receptor

    Science.gov (United States)

    Stamateris, Rachel E.; Sharma, Rohit B.; Kong, Yahui; Ebrahimpour, Pantea; Panday, Deepika; Ranganath, Pavana; Zou, Baobo; Levitt, Helena; Parambil, Nisha Abraham; O’Donnell, Christopher P.; García-Ocaña, Adolfo

    2016-01-01

    An important goal in diabetes research is to understand the processes that trigger endogenous β-cell proliferation. Hyperglycemia induces β-cell replication, but the mechanism remains debated. A prime candidate is insulin, which acts locally through the insulin receptor. Having previously developed an in vivo mouse hyperglycemia model, we tested whether glucose induces β-cell proliferation through insulin signaling. By using mice lacking insulin signaling intermediate insulin receptor substrate 2 (IRS2), we confirmed that hyperglycemia-induced β-cell proliferation requires IRS2 both in vivo and ex vivo. Of note, insulin receptor activation was not required for glucose-induced proliferation, and insulin itself was not sufficient to drive replication. Glucose and insulin caused similar acute signaling in mouse islets, but chronic signaling differed markedly, with mammalian target of rapamycin (MTOR) and extracellular signal–related kinase (ERK) activation by glucose and AKT activation by insulin. MTOR but not ERK activation was required for glucose-induced proliferation. Cyclin D2 was necessary for glucose-induced β-cell proliferation. Cyclin D2 expression was reduced when either IRS2 or MTOR signaling was lost, and restoring cyclin D2 expression rescued the proliferation defect. Human islets shared many of these regulatory pathways. Taken together, these results support a model in which IRS2, MTOR, and cyclin D2, but not the insulin receptor, mediate glucose-induced proliferation. PMID:26740601

  9. Effect of alcohol on insulin secretion and viability of human pancreatic islets

    Directory of Open Access Journals (Sweden)

    Nikolić Dragan

    2017-01-01

    Full Text Available Introduction/Objective. There are controversial data in the literature on the topic of effects of alcohol on insulin secretion, apoptosis, and necrosis of the endocrine and exocrine pancreas. The goal of this research was to determine how alcohol affects the insulin secretion and viability of human adult pancreatic islets in vitro during a seven-day incubation. Methods. Human pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated in Roswell Park Memorial Institute (RPMI medium containing alcohol (10 μl of alcohol in 100 ml of medium. Insulin stimulation index (SI and viability of the islets were determined on the first, third, and seventh day of cultivation. Results. Analysis of the viability of the islets showed that there wasn’t significant difference between the control and the test group. In the test group, viability of the cultures declined with the time of incubation. SI of the test group was higher compared to the control group, by 50% and 25% on the first and third day of cultivation, respectively. On the seventh day, insulin secretion was reduced by 25%. The difference was not statistically significant (p > 0.05. In the test group, significant decline in insulin secretion was found on the third and seventh day of incubation (p ≤ 0.05. Conclusion. Alcohol can increase or decrease insulin secretion of islets cultures, which may result in an inadequate response of pancreatic β-cells to blood glucose, leading to insulin resistance, and increased risk of developing type 2 diabetes. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 41002

  10. The RhoGAP Stard13 controls insulin secretion through F-actin remodeling

    Directory of Open Access Journals (Sweden)

    Heike Naumann

    2018-02-01

    Full Text Available Objective: Actin cytoskeleton remodeling is necessary for glucose-stimulated insulin secretion in pancreatic β-cells. A mechanistic understanding of actin dynamics in the islet is paramount to a better comprehension of β-cell dysfunction in diabetes. Here, we investigate the Rho GTPase regulator Stard13 and its role in F-actin cytoskeleton organization and islet function in adult mice. Methods: We used Lifeact-EGFP transgenic animals to visualize actin cytoskeleton organization and dynamics in vivo in the mouse islets. Furthermore, we applied this model to study actin cytoskeleton and insulin secretion in mutant mice deleted for Stard13 selectively in pancreatic cells. We isolated transgenic islets for 3D-imaging and perifusion studies to measure insulin secretion dynamics. In parallel, we performed histological and morphometric analyses of the pancreas and used in vivo approaches to study glucose metabolism in the mouse. Results: In this study, we provide the first genetic evidence that Stard13 regulates insulin secretion in response to glucose. Postnatally, Stard13 expression became restricted to the mouse pancreatic islets. We showed that Stard13 deletion results in a marked increase in actin polymerization in islet cells, which is accompanied by severe reduction of insulin secretion in perifusion experiments. Consistently, Stard13-deleted mice displayed impaired glucose tolerance and reduced glucose-stimulated insulin secretion. Conclusions: Taken together, our results suggest a previously unappreciated role for the RhoGAP protein Stard13 in the interplay between actin cytoskeletal remodeling and insulin secretion. Keywords: F-actin, Insulin secretion, Islet, Pancreas, Lifeact, Stard13

  11. Islet Oxygen Consumption Rate (OCR) Dose Predicts Insulin Independence in Clinical Islet Autotransplantation.

    Science.gov (United States)

    Papas, Klearchos K; Bellin, Melena D; Sutherland, David E R; Suszynski, Thomas M; Kitzmann, Jennifer P; Avgoustiniatos, Efstathios S; Gruessner, Angelika C; Mueller, Kathryn R; Beilman, Gregory J; Balamurugan, Appakalai N; Loganathan, Gopalakrishnan; Colton, Clark K; Koulmanda, Maria; Weir, Gordon C; Wilhelm, Josh J; Qian, Dajun; Niland, Joyce C; Hering, Bernhard J

    2015-01-01

    Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR) in predicting clinical islet autotransplant (IAT) insulin independence (II). IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity. Membrane integrity staining (FDA/PI), OCR normalized to DNA (OCR/DNA), islet equivalent (IE) and OCR (viable IE) normalized to recipient body weight (IE dose and OCR dose), and OCR/DNA normalized to islet size index (ISI) were used to characterize autoislet preparations (n = 35). Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis. Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001). These islet characterization methods were highly correlated with II at 6-12 months post-IAT (area-under-the-curve (AUC) = 0.94 for IE dose and 0.96 for OCR dose). FDA/PI (AUC = 0.49) and OCR/DNA (AUC = 0.58) did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72). Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations.

  12. Islet Oxygen Consumption Rate (OCR Dose Predicts Insulin Independence in Clinical Islet Autotransplantation.

    Directory of Open Access Journals (Sweden)

    Klearchos K Papas

    Full Text Available Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR in predicting clinical islet autotransplant (IAT insulin independence (II. IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity.Membrane integrity staining (FDA/PI, OCR normalized to DNA (OCR/DNA, islet equivalent (IE and OCR (viable IE normalized to recipient body weight (IE dose and OCR dose, and OCR/DNA normalized to islet size index (ISI were used to characterize autoislet preparations (n = 35. Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis.Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001. These islet characterization methods were highly correlated with II at 6-12 months post-IAT (area-under-the-curve (AUC = 0.94 for IE dose and 0.96 for OCR dose. FDA/PI (AUC = 0.49 and OCR/DNA (AUC = 0.58 did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72.Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations.

  13. Chaotic electrical activity of living β-cells in the mouse pancreatic islet

    Science.gov (United States)

    Kanno, Takahiro; Miyano, Takaya; Tokuda, Isao; Galvanovskis, Juris; Wakui, Makoto

    2007-02-01

    To test for chaotic dynamics of the insulin producing β-cell and explore its biological role, we observed the action potentials with the perforated patch clamp technique, for isolated cells as well as for intact cells of the mouse pancreatic islet. The time series obtained were analyzed using nonlinear diagnostic algorithms associated with the surrogate method. The isolated cells exhibited short-term predictability and visible determinism, in the steady state response to 10 mM glucose, while the intact cells did not. In the latter case, determinism became visible after the application of a gap junction inhibitor. This tendency was enhanced by the stimulation with tolbutamide. Our observations suggest that, thanks to the integration of individual chaotic dynamics via gap junction coupling, the β-cells will lose memory of fluctuations occurring at any instant in their electrical activity more rapidly with time. This is likely to contribute to the functional stability of the islet against uncertain perturbations.

  14. Melatonin and Pancreatic Islets: Interrelationships between Melatonin, Insulin and Glucagon

    Science.gov (United States)

    Peschke, Elmar; Bähr, Ina; Mühlbauer, Eckhard

    2013-01-01

    The pineal hormone melatonin exerts its influence in the periphery through activation of two specific trans-membrane receptors: MT1 and MT2. Both isoforms are expressed in the islet of Langerhans and are involved in the modulation of insulin secretion from β-cells and in glucagon secretion from α-cells. De-synchrony of receptor signaling may lead to the development of type 2 diabetes. This notion has recently been supported by genome-wide association studies identifying particularly the MT2 as a risk factor for this rapidly spreading metabolic disturbance. Since melatonin is secreted in a clearly diurnal fashion, it is safe to assume that it also has a diurnal impact on the blood-glucose-regulating function of the islet. This factor has hitherto been underestimated; the disruption of diurnal signaling within the islet may be one of the most important mechanisms leading to metabolic disturbances. The study of melatonin–insulin interactions in diabetic rat models has revealed an inverse relationship: an increase in melatonin levels leads to a down-regulation of insulin secretion and vice versa. Elucidation of the possible inverse interrelationship in man may open new avenues in the therapy of diabetes. PMID:23535335

  15. Effects of tetracaine on insulin release and calcium handling by rat pancreatic islets

    International Nuclear Information System (INIS)

    Abdel El Motal, S.M.A.; Pian-Smith, M.C.M.; Sharp, G.W.G.

    1987-01-01

    The effects of tetracaine on insulin release and 45 Ca 2+ handling by rat pancreatic islets have been studied under basal, glucose-stimulated, and 3-isobutyl-1-methylxanthine (IBMX)-stimulated conditions. Islets were isolated by the use of collagenase and used either directly (freshly isolated islets) or after a period under tissue culture conditions. Tetracaine was found to stimulate insulin release under basal conditions, to inhibit glucose-stimulated insulin release, and to potentiate insulin release stimulated by IBMX. In studies on the mechanisms underlying these effects, tetracaine was found to decrease glucose-stimulated net retention of 45 Ca 2+ (by an action to block the voltage-dependent Ca channels) and to mobilize Ca 2+ from intracellular stores. These two actions form the basis for the inhibition of glucose-stimulated insulin release, which depends heavily on Ca 2+ entry via the voltage-dependent channels and the synergism with IBMX to potentiate release. No inhibition of IBMX-stimulated release occurs because IBMX does not use the voltage-dependent channels to raise intracellular Ca 2+

  16. Disruption of growth hormone receptor gene causes diminished pancreatic islet size and increased insulin sensitivity in mice.

    Science.gov (United States)

    Liu, Jun-Li; Coschigano, Karen T; Robertson, Katie; Lipsett, Mark; Guo, Yubin; Kopchick, John J; Kumar, Ujendra; Liu, Ye Lauren

    2004-09-01

    Growth hormone, acting through its receptor (GHR), plays an important role in carbohydrate metabolism and in promoting postnatal growth. GHR gene-deficient (GHR(-/-)) mice exhibit severe growth retardation and proportionate dwarfism. To assess the physiological relevance of growth hormone actions, GHR(-/-) mice were used to investigate their phenotype in glucose metabolism and pancreatic islet function. Adult GHR(-/-) mice exhibited significant reductions in the levels of blood glucose and insulin, as well as insulin mRNA accumulation. Immunohistochemical analysis of pancreatic sections revealed normal distribution of the islets despite a significantly smaller size. The average size of the islets found in GHR(-/-) mice was only one-third of that in wild-type littermates. Total beta-cell mass was reduced 4.5-fold in GHR(-/-) mice, significantly more than their body size reduction. This reduction in pancreatic islet mass appears to be related to decreases in proliferation and cell growth. GHR(-/-) mice were different from the human Laron syndrome in serum insulin level, insulin responsiveness, and obesity. We conclude that growth hormone signaling is essential for maintaining pancreatic islet size, stimulating islet hormone production, and maintaining normal insulin sensitivity and glucose homeostasis.

  17. Impact of anti-insulin antibodies on islet transplantation outcome: data from the GRAGIL Network.

    Science.gov (United States)

    Lablanche, Sandrine; Borot, Sophie; Thaunat, Olivier; Bayle, Francois; Badet, Lionel; Morelon, Emmanuel; Thivolet, Charles; Wojtusciszyn, Anne; Frimat, Luc; Kessler, Laurence; Penfornis, Alfred; Brault, Coralie; Colin, Cyrille; Bosco, Domenico; Berney, Thierry; Benhamou, Pierre Y

    2014-08-27

    In patients with type 1 diabetes, insulin antibodies (IA), altering the pharmacokinetics of circulating insulin, might be associated with high glucose concentration, prolonged hypoglycemia, and higher insulin requirement. The impact of IA on islet transplantation has never been explored. Our aim was to evaluate islet transplantation results at 1 year according to the presence of IA. Our work is a retrospective, case-control study, comparing IA-negative and IA-positive patients among the cohort of patients with type 1 diabetes transplanted within the Swiss-French GRAGIL network between 2003 and 2010. Data about IA were available for 17 patients. Before islet transplantation, 10 patients (59%) were screened positive for IA. At 12 months after transplantation, IA-positive patients reached insulin independence less frequently than IA-negative patients (cumulative incidence of insulin independence, 22.2% vs. 71.4%; P=0.02); β score was ≥7 in 43% of IA-negative patients versus 0% in IA-positive patients (P=0.022). When comparing IA-positive patients with IA-negative patients, insulin dose was 0.15 U/kg (0.10-0.18 U/kg) versus 0.01 U/kg (0-0.09 U/kg) (P=0.2); HbA1c was 6.1% (5.8%-6.3%) versus 6.1% (5.9%-6.8%) (P=0.16); basal C-peptide level was 460 ρmol/L (350-510 ρmol/L) versus 265 ρmol/L (177-405 ρmol/L) (P=0.28); occurrence of hypoglycemia was 12.5% versus 16.5% (P=0.9); and homeostatic model assessment insulin resistance was 1.25 (1-2.4) versus 0.7 (0.52-0.92) (P=0.01). After islet transplantation, IA-positive patients achieved insulin independence less frequently, exhibiting lower β score and higher homeostatic model assessment insulin resistance compared with IA-negative patients. However, in both groups, islet transplantation restored good glycemic control and drastically reduced hypoglycemia and insulin requirements.

  18. Glucoregulation after canine islet transplantation : Contribution of insulin secretory capacity, insulin action, and the entero-insular axis

    NARCIS (Netherlands)

    vanderBurg, MPM; van Suylichem, PTR; Guicherit, OR; Frolich, M; Lemkes, HHPJ; Gooszen, HG

    1997-01-01

    The physiological glucoregulatory mechanisms after islet transplantation have been incompletely investigated, We studied the insulin secretory capacity (ISC) by intravenous arginine stimulation during 35-mM glucose clamps, insulin action during hyperinsulinemic euglycemic clamps, and mixed-meal

  19. Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment

    Directory of Open Access Journals (Sweden)

    Omaima M Sabek

    2016-04-01

    Full Text Available Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow–derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland to support islet-like insulin-producing aggregates’ survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland—islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy.

  20. Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment.

    Science.gov (United States)

    Sabek, Omaima M; Farina, Marco; Fraga, Daniel W; Afshar, Solmaz; Ballerini, Andrea; Filgueira, Carly S; Thekkedath, Usha R; Grattoni, Alessandro; Gaber, A Osama

    2016-01-01

    Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow-derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland) to support islet-like insulin-producing aggregates' survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland-islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy.

  1. Biotin enhances ATP synthesis in pancreatic islets of the rat, resulting in reinforcement of glucose-induced insulin secretion.

    Science.gov (United States)

    Sone, Hideyuki; Sasaki, Yuka; Komai, Michio; Toyomizu, Masaaki; Kagawa, Yasuo; Furukawa, Yuji

    2004-02-13

    Previous studies showed that biotin enhanced glucose-induced insulin secretion. Changes in the cytosolic ATP/ADP ratio in the pancreatic islets participate in the regulation of insulin secretion by glucose. In the present study we investigated whether biotin regulates the cytosolic ATP/ADP ratio in glucose-stimulated islets. When islets were stimulated with glucose plus biotin, the ATP/ADP ratio increased to approximately 160% of the ATP/ADP ratio in islets stimulated with glucose alone. The rate of glucose oxidation, assessed by CO(2) production, was also about 2-fold higher in islets treated with biotin. These increasing effects of biotin were proportional to the effects seen in insulin secretion. There are no previous reports of vitamins, such as biotin, directly affecting ATP synthesis. Our data indicate that biotin enhances ATP synthesis in islets following the increased rate of substrate oxidation in mitochondria and that, as a consequence of these events, glucose-induced insulin release is reinforced by biotin.

  2. Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets

    International Nuclear Information System (INIS)

    Douillet, Christelle; Currier, Jenna; Saunders, Jesse; Bodnar, Wanda M.; Matoušek, Tomáš; Stýblo, Miroslav

    2013-01-01

    Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAs III ) or its methylated trivalent metabolites, methylarsonite (MAs III ) and dimethylarsinite (DMAs III ), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAs III , MAs III or DMAs III inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAs III and DMAs III were more potent than iAs III as GSIS inhibitors with estimated IC 50 ≤ 0.1 μM. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAs III , MAs III or DMAs III could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic β-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes. - Highlights: ► Trivalent arsenicals inhibit glucose stimulated insulin secretion by pancreatic islets. ► MAs III and DMAs III are more potent inhibitors than arsenite with IC 50 ∼ 0.1 μM. ► The arsenicals have little or no effects on insulin expression in pancreatic islets. ► The inhibition of insulin secretion by arsenite, MAs III or DMAs III is reversible. ► Thus

  3. Phosphatidylcholine biosynthesis and insulin release in rat islets of Langerhans

    International Nuclear Information System (INIS)

    Hoffman, J.M.

    1988-01-01

    Turnover of phosphatidylcholine (PC) has been demonstrated to play a role in glucose stimulation of insulin release by pancreatic islets of Langerhans. The activity of the islet CDP-choline pathway of PC synthesis was determined by measuring the incorporation of radiolabeled choline or 32 PO 4 into PC, phosphorylcholine and CDP-choline. Concurrently, insulin release was measured by radioimmunoassay to correlate insulin release and PC synthesis. Glucose concentrations greater than 8.5 mM stimulated CDP-choline pathway activity. However, measurement of PC lipid phosphorus tended to decrease, suggesting that stimulation of the CDP-choline pathway was a means of replenishing PC pools diminished by hydrolysis of PC. Inhibition of glucose oxidation by mannoheptulose or incubations under hypoxic conditions prevented stimulation of the CDP-choline pathway, while inhibition of phospholipase A 2 (PLA 2 ) and secretion by the removal of extracellular Ca 2+ potentiated the stimulation seen with glucose

  4. Transcriptomic profiling of pancreatic alpha, beta and delta cell populations identifies delta cells as a principal target for ghrelin in mouse islets

    DEFF Research Database (Denmark)

    Adriaenssens, Alice E; Svendsen, Berit; Lam, Brian Y H

    2016-01-01

    cytometry and analysed by RNA sequencing. The role of the ghrelin receptor was validated by imaging delta cell calcium concentrations using islets with delta cell restricted expression of the calcium reporter GCaMP3, and in perfused mouse pancreases. RESULTS: A database was constructed of all genes...... expressed in alpha, beta and delta cells. The gene encoding the ghrelin receptor, Ghsr, was highlighted as being highly expressed and enriched in delta cells. Activation of the ghrelin receptor raised cytosolic calcium levels in primary pancreatic delta cells and enhanced somatostatin secretion in perfused...... pancreases, correlating with a decrease in insulin and glucagon release. The inhibition of insulin secretion by ghrelin was prevented by somatostatin receptor antagonism. CONCLUSIONS/INTERPRETATION: Our transcriptomic database of genes expressed in the principal islet cell populations will facilitate...

  5. Redifferentiation of insulin-secreting cells after in vitro expansion of adult human pancreatic islet tissue

    International Nuclear Information System (INIS)

    Lechner, Andreas; Nolan, Anna L.; Blacken, Robyn A.; Habener, Joel F.

    2005-01-01

    Cellular replacement therapy holds promise for the treatment of diabetes mellitus but donor tissue is severely limited. Therefore, we investigated whether insulin-secreting cells could be differentiated in vitro from a monolayer of cells expanded from human donor pancreatic islets. We describe a three-step culture protocol that allows for the efficient generation of insulin-producing cell clusters from in vitro expanded, hormone-negative cells. These clusters express insulin at levels of up to 34% that of average freshly isolated human islets and secrete C-peptide upon membrane depolarization. They also contain cells expressing the other major islet hormones (glucagon, somatostatin, and pancreatic polypeptide). The source of the newly differentiated endocrine cells could either be indigenous stem/progenitor cells or the proliferation-associated dedifferentiation and subsequent redifferentiation of mature endocrine cells. The in vitro generated cell clusters may be efficacious in providing islet-like tissue for transplantation into diabetic recipients

  6. Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets

    Energy Technology Data Exchange (ETDEWEB)

    Douillet, Christelle [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Currier, Jenna [Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Saunders, Jesse [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Bodnar, Wanda M. [Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431 (United States); Matoušek, Tomáš [Institute of Analytical Chemistry of the ASCR, v.v.i., Veveří 97, 602 00 Brno (Czech Republic); Stýblo, Miroslav, E-mail: styblo@med.unc.edu [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States)

    2013-02-15

    Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAs{sup III}) or its methylated trivalent metabolites, methylarsonite (MAs{sup III}) and dimethylarsinite (DMAs{sup III}), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAs{sup III}, MAs{sup III} or DMAs{sup III} inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAs{sup III} and DMAs{sup III} were more potent than iAs{sup III} as GSIS inhibitors with estimated IC{sub 50} ≤ 0.1 μM. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAs{sup III}, MAs{sup III} or DMAs{sup III} could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic β-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes. - Highlights: ► Trivalent arsenicals inhibit glucose stimulated insulin secretion by pancreatic islets. ► MAs{sup III} and DMAs{sup III} are more potent inhibitors than arsenite with IC{sub 50} ∼ 0.1 μM. ► The arsenicals have little or no effects on insulin expression in pancreatic islets. ► The inhibition of

  7. Introducing a New Experimental Islet Transplantation Model using Biomimetic Hydrogel and a Simple High Yield Islet Isolation Technique.

    Science.gov (United States)

    Mohammadi Ayenehdeh, Jamal; Niknam, Bahareh; Hashemi, Seyed Mahmoud; Rahavi, Hossein; Rezaei, Nima; Soleimani, Masoud; Tajik, Nader

    2017-07-01

    Islet transplantation could be an ideal alternative treatment to insulin therapy for type 1 diabetes Mellitus (T1DM). This clinical and experimental field requires a model that covers problems such as requiring a large number of functional and viable islets, the optimal transplantation site, and the prevention of islet dispersion. Hence, the methods of choice for isolation of functional islets and transplantation are crucial. The present study has introduced an experimental model that overcomes some critical issues in islet transplantation, including in situ pancreas perfusion by digestive enzymes through common bile duct. In comparison with conventional methods, we inflated the pancreas in Petri dishes with only 1 ml collagenase type XI solution, which was followed by hand-picking isolation or Ficoll gradient separation to purify the islets. Then we used a hydrogel composite in which the islets were embedded and transplanted into the peritoneal cavity of the streptozotocin-induced diabetic C57BL/6 mice. As compared to the yield of the classical methods, in our modified technique, the mean yield of isolation was about 130-200 viable islets/mouse pancreas. In vitro glucose-mediated insulin secretion assay indicated an appropriate response in isolated islets. In addition, data from in vivo experiments revealed that the allograft remarkably maintained blood glucose levels under 400 mg/dl and hydrogel composite prevents the passage of immune cells. In the model presented here, the rapid islet isolation technique and the application of biomimetic hydrogel wrapping of islets could facilitate islet transplantation procedures.

  8. Selective destruction of mouse islet beta cells by human T lymphocytes in a newly-established humanized type 1 diabetic model

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yong, E-mail: yongzhao@uic.edu [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Guo, Chengshan; Hwang, David; Lin, Brian; Dingeldein, Michael; Mihailescu, Dan; Sam, Susan; Sidhwani, Seema [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Zhang, Yongkang [Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Jain, Sumit [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Skidgel, Randal A. [Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Prabhakar, Bellur S. [Department of Immunology and Microbiology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Mazzone, Theodore [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Holterman, Mark J. [Department of Surgery, University of Illinois at Chicago, Chicago, IL 60612 (United States)

    2010-09-03

    Research highlights: {yields} Establish a human immune-mediated type 1 diabetic model in NOD-scid IL2r{gamma}{sup null} mice. {yields} Using the irradiated diabetic NOD mouse spleen mononuclear cells as trigger. {yields} The islet {beta} cells were selectively destroyed by infiltrated human T cells. {yields} The model can facilitate translational research to find a cure for type 1 diabetes. -- Abstract: Type 1 diabetes (T1D) is caused by a T cell-mediated autoimmune response that leads to the loss of insulin-producing {beta} cells. The optimal preclinical testing of promising therapies would be aided by a humanized immune-mediated T1D model. We develop this model in NOD-scid IL2r{gamma}{sup null} mice. The selective destruction of pancreatic islet {beta} cells was mediated by human T lymphocytes after an initial trigger was supplied by the injection of irradiated spleen mononuclear cells (SMC) from diabetic nonobese diabetic (NOD) mice. This resulted in severe insulitis, a marked loss of total {beta}-cell mass, and other related phenotypes of T1D. The migration of human T cells to pancreatic islets was controlled by the {beta} cell-produced highly conserved chemokine stromal cell-derived factor 1 (SDF-1) and its receptor C-X-C chemokine receptor (CXCR) 4, as demonstrated by in vivo blocking experiments using antibody to CXCR4. The specificity of humanized T cell-mediated immune responses against islet {beta} cells was generated by the local inflammatory microenvironment in pancreatic islets including human CD4{sup +} T cell infiltration and clonal expansion, and the mouse islet {beta}-cell-derived CD1d-mediated human iNKT activation. The selective destruction of mouse islet {beta} cells by a human T cell-mediated immune response in this humanized T1D model can mimic those observed in T1D patients. This model can provide a valuable tool for translational research into T1D.

  9. Glucose-stimulated calcium dynamics in islets of Langerhans in acute mouse pancreas tissue slices.

    Directory of Open Access Journals (Sweden)

    Andraž Stožer

    Full Text Available In endocrine cells within islets of Langerhans calcium ions couple cell stimulation to hormone secretion. Since the advent of modern fluorimetry, numerous in vitro studies employing primarily isolated mouse islets have investigated the effects of various secretagogues on cytoplasmic calcium, predominantly in insulin-secreting beta cells. Due to technical limitations, insights of these studies are inherently limited to a rather small subpopulation of outermost cells. The results also seem to depend on various factors, like culture conditions and duration, and are not always easily reconcilable with findings in vivo. The main controversies regard the types of calcium oscillations, presence of calcium waves, and the level of synchronized activity. Here, we set out to combine the in situ acute mouse pancreas tissue slice preparation with noninvasive fluorescent calcium labeling and subsequent confocal laser scanning microscopy to shed new light on the existing controversies utilizing an innovative approach enabling the characterization of responses in many cells from all layers of islets. Our experiments reproducibly showed stable fast calcium oscillations on a sustained plateau rather than slow oscillations as the predominant type of response in acute tissue slices, and that calcium waves are the mechanistic substrate for synchronization of oscillations. We also found indirect evidence that even a large amplitude calcium signal was not sufficient and that metabolic activation was necessary to ensure cell synchronization upon stimulation with glucose. Our novel method helped resolve existing controversies and showed the potential to help answer important physiological questions, making it one of the methods of choice for the foreseeable future.

  10. Differential expression of islet glutaredoxin 1 and 5 with high reactive oxygen species production in a mouse model of diabesity.

    Science.gov (United States)

    Petry, Sebastian Friedrich; Sharifpanah, Fatemeh; Sauer, Heinrich; Linn, Thomas

    2017-01-01

    The onset and progression of diabetes mellitus type 2 is highly contingent on the amount of functional beta-cell mass. An underlying cause of beta-cell decay in diabetes is oxidative stress, which markedly affects the insulin producing pancreatic cells due to their poor antioxidant defence capacity. Consequently, disturbances of cellular redox signaling have been implicated to play a major role in beta-cell loss in diabetes mellitus type 2. There is evidence suggesting that the glutaredoxin (Grx) system exerts a protective role for pancreatic islets, but the exact mechanisms have not yet been elucidated. In this study, a mouse model for diabetes mellitus type 2 was used to gain further insight into the significance of Grx for the islets of Langerhans in the diabetic metabolism. We have observed distinct differences in the expression levels of Grx in pancreatic islets between obese, diabetic db mice and lean, non-diabetic controls. This finding is the first report about a decrease of Grx expression levels in pancreatic islets of diabetic mice which was accompanied by declining insulin secretion, increase of reactive oxygen species (ROS) production level, and cell cycle alterations. These data demonstrate the essential role of the Grx system for the beta-cell during metabolic stress which may provide a new target for diabetes mellitus type 2 treatment.

  11. Effect of interleukin-1 on the biosynthesis of proinsulin and insulin in isolated rat pancreatic islets

    DEFF Research Database (Denmark)

    Hansen, Birgit Sehested; Linde, S; Spinas, G A

    1988-01-01

    Insulin dependent diabetes mellitus (IDDM) is often preceded or associated with lymphocytic infiltration in the islets of Langerhans (insulitis). We recently demonstrated that interleukin-1 (IL-1) produced by activated macrophages exerts a bimodal effect on insulin release and biosynthesis...... in isolated rat islets. In the present study we have further analysed the effect of recombinant human interleukin-1 beta (rIL-1) on the biosynthesis and conversion of proinsulin 1 and 2 in rat islets. By RP-HPLC-analysis of islets labelled with [3H]leucine we found that exposure to 6 ng/ml of IL-1 for 24 h.......1 to 3.4 +/- 0.4, respectively. Pulse-chase experiments with [3H]leucine and [35S]methionine indicated a more marked reduction in the conversion rate of proinsulin-2 compared to that of proinsulin-1. In conclusion these experiments demonstrate that IL-1 inhibits insulin biosynthesis by preferential...

  12. Factors influencing insulin and glucagon secretion in lean and genetically obese mice

    International Nuclear Information System (INIS)

    Beloff-Chain, A.; Newman, M.E.; Mansford, K.R.L.

    1977-01-01

    The control of 125 I-labelled insulin and glucagon secretion from isolated pancreatic islets of lean and genetically obese mice has been compared. The enlarged islets of obese mouse pancreas and islets of obese mice maintained on a restricted diet manifested a greater response to glucose stimulation of insulin secretion than the lean mice islets. The glucagon content of the islets, the secretion of glucagon in a medium containing 150 mg% glucose and the stimulation of glucagon secretion by arginine did not differ significantly in the two groups. Adrenaline stimulated glucagon secretion in vitro from obese mice but not from lean mice. Antiinsulin serum injections into obese mice increased the plasma glucagon levels about twofold and had no effect on glucagon levels in lean mice, although the level of hyperglycaemia was the same in both groups. It is suggested that the suppression of glucagon release by glucose requires a higher concentration of insulin in the obese mouse pancreas than in lean mice. (orig./AJ) [de

  13. Factors influencing insulin and glucagon secretion in lean and genetically obese mice

    Energy Technology Data Exchange (ETDEWEB)

    Beloff-Chain, A; Newman, M E; Mansford, K R.L. [Imperial Coll. of Science and Technology, London (UK). Dept. of Biochemistry

    1977-01-01

    The control of /sup 125/I-labelled insulin and glucagon secretion from isolated pancreatic islets of lean and genetically obese mice has been compared. The enlarged islets of obese mouse pancreas and islets of obese mice maintained on a restricted diet manifested a greater response to glucose stimulation of insulin secretion than the lean mice islets. The glucagon content of the islets, the secretion of glucagon in a medium containing 150 mg% glucose and the stimulation of glucagon secretion by arginine did not differ significantly in the two groups. Adrenaline stimulated glucagon secretion in vitro from obese mice but not from lean mice. Antiinsulin serum injections into obese mice increased the plasma glucagon levels about twofold and had no effect on glucagon levels in lean mice, although the level of hyperglycaemia was the same in both groups. It is suggested that the suppression of glucagon release by glucose requires a higher concentration of insulin in the obese mouse pancreas than in lean mice.

  14. Serine racemase is expressed in islets and contributes to the regulation of glucose homeostasis.

    Science.gov (United States)

    Lockridge, Amber D; Baumann, Daniel C; Akhaphong, Brian; Abrenica, Alleah; Miller, Robert F; Alejandro, Emilyn U

    2016-11-01

    NMDA receptors (NMDARs) have recently been discovered as functional regulators of pancreatic β-cell insulin secretion. While these excitatory receptor channels have been extensively studied in the brain for their role in synaptic plasticity and development, little is known about how they work in β-cells. In neuronal cells, NMDAR activation requires the simultaneous binding of glutamate and a rate-limiting co-agonist, such as D-serine. D-serine levels and availability in most of the brain rely on endogenous synthesis by the enzyme serine racemase (Srr). Srr transcripts have been reported in human and mouse islets but it is not clear whether Srr is functionally expressed in β-cells or what its role in the pancreas might be. In this investigation, we reveal that Srr protein is highly expressed in primary human and mouse β-cells. Mice with whole body deletion of Srr (Srr KO) show improved glucose tolerance through enhanced insulin secretory capacity, possibly through Srr-mediated alterations in islet NMDAR expression and function. We observed elevated insulin sensitivity in some animals, suggesting Srr metabolic regulation in other peripheral organs as well. Srr expression in neonatal and embryonic islets, and adult deficits in Srr KO pancreas weight and islet insulin content, point toward a potential role for Srr in pancreatic development. These data reveal the first evidence that Srr may regulate glucose homeostasis in peripheral tissues and provide circumstantial evidence that D-serine may be an endogenous islet NMDAR co-agonist in β-cells.

  15. The Placental Secretome: Identifying Potential Cross-Talk Between Placenta and Islet β-Cells

    Directory of Open Access Journals (Sweden)

    Robert Drynda

    2018-02-01

    Full Text Available Background/Aims: Insulin-secreting islet β-cells adapt to the insulin resistance associated with pregnancy by increasing functional β-cell mass, but the placental signals involved in this process are not well defined. In the current study, we analysed expression of G-protein coupled receptor (GPCR mRNAs in mouse islets and islet GPCR ligand mRNAs in placenta during pregnancy to generate an atlas of potential interactions between the placenta and β-cells to inform future functional studies of islet adaptive responses to pregnancy. Methods: Quantative RT-PCR arrays were used to measure mRNA expression levels of: (i 342 GPCRs in islets from non-pregnant mice, and in islets isolated from mice on gestational days 12 and 18; (ii 126 islet GPCR ligands in mouse placenta at gestational days 12 and 18. Results: At gestational day 12, a time of rapid expansion of the β-cell mass, 189 islet GPCR mRNAs were quantifiable, while 79 of the 126 known islet GPCR ligand mRNAs were detectable in placental extracts. Approximately half of the quantifiable placental GPCR ligand genes were of unknown function in β-cells. The expression of some islet GPCR and placental ligand mRNAs varied during pregnancy, with altered expression of both GPCR and ligand mRNAs by gestational day 18. Conclusion: The current study has revealed numerous potential routes for interaction between the placenta and islets, and offers an atlas to inform further functional studies of their roles in adaptive responses to pregnancy, and in the regulation of the β-cell mass.

  16. Genetically Engineered Islets and Alternative Sources of Insulin-Producing Cells for Treating Autoimmune Diabetes: Quo Vadis?

    Directory of Open Access Journals (Sweden)

    Feng-Cheng Chou

    2012-01-01

    Full Text Available Islet transplantation is a promising therapy for patients with type 1 diabetes that can provide moment-to-moment metabolic control of glucose and allow them to achieve insulin independence. However, two major problems need to be overcome: (1 detrimental immune responses, including inflammation induced by the islet isolation/transplantation procedure, recurrence autoimmunity, and allorejection, can cause graft loss and (2 inadequate numbers of organ donors. Several gene therapy approaches and pharmaceutical treatments have been demonstrated to prolong the survival of pancreatic islet grafts in animal models; however, the clinical applications need to be investigated further. In addition, for an alternative source of pancreatic β-cell replacement therapy, the ex vivo generation of insulin-secreting cells from diverse origins of stem/progenitor cells has become an attractive option in regenerative medicine. This paper focuses on the genetic manipulation of islets during transplantation therapy and summarizes current strategies to obtain functional insulin-secreting cells from stem/progenitor cells.

  17. Experimental evaluation and computational modeling of the effects of encapsulation on the time-profile of glucose-stimulated insulin release of pancreatic islets.

    Science.gov (United States)

    Buchwald, Peter; Cechin, Sirlene R; Weaver, Jessica D; Stabler, Cherie L

    2015-03-28

    In type 1 diabetic patients, who have lost their ability to produce insulin, transplantation of pancreatic islet cells can normalize metabolic control in a manner that is not achievable with exogenous insulin. To be successful, this procedure has to address the problems caused by the immune and autoimmune responses to the graft. Islet encapsulation using various techniques and materials has been and is being extensively explored as a possible approach. Within this framework, it is of considerable interest to characterize the effect encapsulation has on the insulin response of pancreatic islets. To improve our ability to quantitatively describe the glucose-stimulated insulin release (GSIR) of pancreatic islets in general and of micro-encapsulated islets in particular, we performed dynamic perifusion experiments with frequent sampling. We used unencapsulated and microencapsulated murine islets in parallel and fitted the results with a complex local concentration-based finite element method (FEM) computational model. The high-resolution dynamic perifusion experiments allowed good characterization of the first-phase and second-phase insulin secretion, and we observed a slightly delayed and blunted first-phase insulin response for microencapsulated islets when compared to free islets. Insulin secretion profiles of both free and encapsulated islets could be fitted well by a COMSOL Multiphysics model that couples hormone secretion and nutrient consumption kinetics with diffusive and convective transport. This model, which was further validated and calibrated here, can be used for arbitrary geometries and glucose stimulation sequences and is well suited for the quantitative characterization of the insulin response of cultured, perifused, transplanted, or encapsulated islets. The present high-resolution GSIR experiments allowed for direct characterization of the effect microencapsulation has on the time-profile of insulin secretion. The multiphysics model, further validated

  18. Liver-derived systemic factors drive β-cell hyperplasia in insulin resistant states

    Energy Technology Data Exchange (ETDEWEB)

    El Ouaamari, Abdelfattah; Kawamori, Dan; Dirice, Ercument; Liew, Chong Wee; Shadrach, Jennifer L.; Hu, Jiang; Katsuta, Hitoshi; Hollister-Lock, Jennifer; Qian, Weijun; Wagers, Amy J.; Kulkarni, Rohit N.

    2013-02-21

    Integrative organ cross-talk regulates key aspects of energy homeostasis and its dysregulation may underlie metabolic disorders such as obesity and diabetes. To test the hypothesis that cross-talk between the liver and pancreatic islets modulates β-cell growth in response to insulin resistance, we used the Liver-specific Insulin Receptor Knockout (LIRKO) mouse, a unique model that exhibits dramatic islet hyperplasia. Using complementary in vivo parabiosis and transplantation assays, and in vitro islet culture approaches, we demonstrate that humoral, non-neural, non-cell autonomous factor(s) induce β-cell proliferation in LIRKO mice. Furthermore, we report that a hepatocyte-derived factor(s) stimulates mouse and human β-cell proliferation in ex vivo assays, independent of ambient glucose and insulin levels. These data implicate the liver as a critical source of β-cell growth factors in insulin resistant states.

  19. Harnessing the Foreign Body Reaction in Marginal Mass Device-less Subcutaneous Islet Transplantation in Mice.

    Science.gov (United States)

    Pepper, Andrew R; Pawlick, Rena; Bruni, Antonio; Gala-Lopez, Boris; Wink, John; Rafiei, Yasmin; Bral, Mariusz; Abualhassan, Nasser; Shapiro, A M James

    2016-07-01

    Islet transplantation is a successful β-cell replacement therapy for selected patients with type 1 diabetes mellitus. However, despite early insulin independence, long-term graft attrition gradually reverts recipients to exogenous insulin dependency. Undoubtedly, as insulin producing stem cell therapies progress, a transplant site that is retrievable is desirable. This prerequisite is currently incompatible with intrahepatic islet transplantation. Herein, we evaluate the functional capacity of a prevascularized subcutaneous site to accommodate marginal islet mass transplantation in mice. Syngeneic mouse islets (150) were transplanted either under the kidney capsule (KC), into a prevascularized subcutaneous device-less (DL) site, or into the unmodified subcutaneous (SC) tissue. The DL site was created 4 weeks before diabetes induction and islet transplantation through the transient placement of a 5-Fr vascular catheter. Recipient mice were monitored for glycemic control and intraperitoneal glucose tolerance. A marginal islet mass transplanted into the DL site routinely reversed diabetes (n = 13 of 18) whereas all SC islet recipients failed to restore glycemic control (n = 0 of 10, P islet-KC mice (n = 15 of 16) became euglycemic posttransplant. The DL recipients' glucose profiles were comparable to KC islet grafts, postintrapertioneal glucose tolerance testing, whereas SC recipients remained hyperglycemic postglucose challenge. All normoglycemic mice maintained graft function for 100 days until graft retrieval. DL and KC islet grafts stained positively for insulin, microvessels, and a collagen scaffold. The device-less prevascularized approach supports marginal mass islet engraftment in mice.

  20. Interleukin-33-Activated Islet-Resident Innate Lymphoid Cells Promote Insulin Secretion through Myeloid Cell Retinoic Acid Production.

    Science.gov (United States)

    Dalmas, Elise; Lehmann, Frank M; Dror, Erez; Wueest, Stephan; Thienel, Constanze; Borsigova, Marcela; Stawiski, Marc; Traunecker, Emmanuel; Lucchini, Fabrizio C; Dapito, Dianne H; Kallert, Sandra M; Guigas, Bruno; Pattou, Francois; Kerr-Conte, Julie; Maechler, Pierre; Girard, Jean-Philippe; Konrad, Daniel; Wolfrum, Christian; Böni-Schnetzler, Marianne; Finke, Daniela; Donath, Marc Y

    2017-11-21

    Pancreatic-islet inflammation contributes to the failure of β cell insulin secretion during obesity and type 2 diabetes. However, little is known about the nature and function of resident immune cells in this context or in homeostasis. Here we show that interleukin (IL)-33 was produced by islet mesenchymal cells and enhanced by a diabetes milieu (glucose, IL-1β, and palmitate). IL-33 promoted β cell function through islet-resident group 2 innate lymphoid cells (ILC2s) that elicited retinoic acid (RA)-producing capacities in macrophages and dendritic cells via the secretion of IL-13 and colony-stimulating factor 2. In turn, local RA signaled to the β cells to increase insulin secretion. This IL-33-ILC2 axis was activated after acute β cell stress but was defective during chronic obesity. Accordingly, IL-33 injections rescued islet function in obese mice. Our findings provide evidence that an immunometabolic crosstalk between islet-derived IL-33, ILC2s, and myeloid cells fosters insulin secretion. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Effect of gamma-irradiation on mouse pancreatic islet-allograft survival

    International Nuclear Information System (INIS)

    Kanai, T.; Porter, J.; Gotoh, M.; Monaco, A.P.; Maki, T.

    1989-01-01

    Elimination or inactivation of lymphoid tissue in the pancreatic islet preparation achieves prolongation of islet-allograft survival. In this study we examined the effect of gamma-irradiation on mouse islet-allograft survival. In a B6AF1 isograft model, irradiation up to 2400 rad did not induce deterioration of islet function over 200 days, but greater doses caused cessation of graft function between 83 and 186 days. When DBA/2 crude islets were transplanted into B6AF1 recipients, all nonirradiated allografts were acutely rejected. Marked prolongation of allograft survival was achieved by islet irradiation with doses between 800 and 12,000 rad. With higher doses, significant numbers of allografts survived beyond the controls, but many lost function between 78 and 180 days, with none surviving greater than 200 days. Irradiation with 16,000 rad caused acute radiation damage. Because most secondary islet allografts in recipient mice that lost primary islet-graft function between 84 and 195 days survived greater than 100 days, late functional loss was probably due to the radiation injury. Combined use of recipient treatment with cyclosporin A and graft irradiation (2400 rad) achieved prolongation of DBA/2 islets in B6AF1 mice

  2. Blood-based biomarkers of age-associated epigenetic changes in human islets associate with insulin secretion and diabetes

    DEFF Research Database (Denmark)

    Bacos, Karl; Gillberg, Linn; Volkov, Petr

    2016-01-01

    identified in human islets (for example, KLF14, FHL2, ZNF518B and FAM123C) and some associate with insulin secretion and T2D. DNA methylation correlates with islet expression of multiple genes, including FHL2, ZNF518B, GNPNAT1 and HLTF. Silencing these genes in β-cells alter insulin secretion. Together, we...

  3. Glycemia, Hypoglycemia, and Costs of Simultaneous Islet-Kidney or Islet After Kidney Transplantation Versus Intensive Insulin Therapy and Waiting List for Islet Transplantation.

    Science.gov (United States)

    Gerber, Philipp A; Locher, Rebecca; Zuellig, Richard A; Tschopp, Oliver; Ajdler-Schaeffler, Evelyne; Kron, Philipp; Oberkofler, Christian; Brändle, Michael; Spinas, Giatgen A; Lehmann, Roger

    2015-10-01

    Long-term data of patients with type 1 diabetes mellitus (T1D) after simultaneous islet-kidney (SIK) or islet-after-kidney transplantation (IAK) are rare and have never been compared to intensified insulin therapy (IIT). Twenty-two patients with T1D and end-stage renal failure undergoing islet transplantation were compared to 70 patients matched for age and diabetes duration treated with IIT and to 13 patients with kidney transplantation alone or simultaneous pancreas-kidney after loss of pancreas function (waiting list for IAK [WLI]). Glycemic control, severe hypoglycemia, insulin requirement, and direct medical costs were analyzed. Glycated hemoglobin decreased significantly from 8.2 ± 1.5 to 6.7 ± 0.9% at the end of follow-up (mean 7.2 ± 2.5 years) in the SIK/IAK and remained constant in IIT (7.8 ± 1.0% and 7.6 ± 1.0) and WLI (7.8 ± 0.8 and 7.9 ± 1.0%). Daily insulin requirement decreased from 0.53 ± 0.15 to 0.29 ± 0.26 U/kg and remained constant in IIT (0.59 ± 0.19 and 0.58 ± 0.23 U/kg) and in WLI (0.76 ± 0.28 and 0.73 ± 0.11 U/kg). Severe hypoglycemia dropped in SIK/IAK from 4.5 ± 9.7 to 0.3 ± 0.7/patient-year and remained constant in IIT (0.1 ± 0.7 and 0.2 ± 0.8/patient-year). Detailed cost analysis revealed US $57,525 of additional cost for islet transplantation 5 years after transplantation. Based on a 5- and 10-year analysis, cost neutrality is assumed to be achieved 15 years after transplantation. This long-term cohort with more than 7 years of follow-up shows that glycemic control in patients with T1D after SIK/IAK transplantation improved, and the rate of severe hypoglycemia decreased significantly as compared to control groups. Cost analysis revealed that islet transplantation is estimated to be cost neutral at 15 years after transplantation.

  4. Extensive Loss of Islet Mass Beyond the First Day After Intraportal Human Islet Transplantation in a Mouse Model.

    Science.gov (United States)

    Liljebäck, Hanna; Grapensparr, Liza; Olerud, Johan; Carlsson, Per-Ola

    2016-01-01

    Clinical islet transplantation is characterized by a progressive deterioration of islet graft function, which renders many patients once again dependent on exogenous insulin administration within a couple of years. In this study, we aimed to investigate possible engraftment factors limiting the survival and viability of experimentally transplanted human islets beyond the first day after their transplantation to the liver. Human islets were transplanted into the liver of nude mice and characterized 1 or 30 days after transplantation by immunohistochemistry. The factors assessed were endocrine mass, cellular death, hypoxia, vascular density and amyloid formation in the transplanted islets. One day posttransplantation, necrotic cells, as well as apoptotic cells, were commonly observed. In contrast to necrotic death, apoptosis rates remained high 1 month posttransplantation, and the total islet mass was reduced by more than 50% between 1 and 30 days posttransplantation. Islet mass at 30 days posttransplantation correlated negatively to apoptotic death. Vascular density within the transplanted islets remained less than 30% of that in native human islets up to 30 days posttransplantation and was associated with prevailing hypoxia. Amyloid formation was rarely observed in the 1-day-old transplants, but was commonly observed in the 30-day-old islet transplants. We conclude that substantial islet cell death occurs beyond the immediate posttransplantation phase, particularly through apoptotic events. Concomitant low vascularization with prevailing hypoxia and progressive amyloid development was observed in the human islet grafts. Strategies to improve engraftment at the intraportal site or change of implantation site in the clinical setting are needed.

  5. In vivo islet protection by a nuclear import inhibitor in a mouse model of type 1 diabetes.

    Directory of Open Access Journals (Sweden)

    Daniel J Moore

    2010-10-01

    Full Text Available Insulin-dependent Type 1 diabetes (T1D is a devastating autoimmune disease that destroys beta cells within the pancreatic islets and afflicts over 10 million people worldwide. These patients face life-long risks for blindness, cardiovascular and renal diseases, and complications of insulin treatment. New therapies that protect islets from autoimmune destruction and allow continuing insulin production are needed. Increasing evidence regarding the pathomechanism of T1D indicates that islets are destroyed by the relentless attack by autoreactive immune cells evolving from an aberrant action of the innate, in addition to adaptive, immune system that produces islet-toxic cytokines, chemokines, and other effectors of islet inflammation. We tested the hypothesis that targeting nuclear import of stress-responsive transcription factors evoked by agonist-stimulated innate and adaptive immunity receptors would protect islets from autoimmune destruction.Here we show that a first-in-class inhibitor of nuclear import, cSN50 peptide, affords in vivo islet protection following a 2-day course of intense treatment in NOD mice, which resulted in a diabetes-free state for one year without apparent toxicity. This nuclear import inhibitor precipitously reduces the accumulation of islet-destructive autoreactive lymphocytes while enhancing activation-induced cell death of T and B lymphocytes derived from autoimmune diabetes-prone, non-obese diabetic (NOD mice that develop T1D. Moreover, in this widely used model of human T1D we noted attenuation of pro-inflammatory cytokine and chemokine production in immune cells.These results indicate that a novel form of immunotherapy that targets nuclear import can arrest inflammation-driven destruction of insulin-producing beta cells at the site of autoimmune attack within pancreatic islets during the progression of T1D.

  6. Pancreas-After-Islet Transplantation in Nonuremic Type 1 Diabetes: A Strategy for Restoring Durable Insulin Independence.

    Science.gov (United States)

    Wisel, S A; Gardner, J M; Roll, G R; Harbell, J; Freise, C E; Feng, S; Kang, S M; Hirose, R; Kaufman, D B; Posselt, A M; Stock, P G

    2017-09-01

    Islet transplantation offers a minimally invasive approach for β cell replacement in diabetic patients with hypoglycemic unawareness. Attempts at insulin independence may require multiple islet reinfusions from distinct donors, increasing the risk of allogeneic sensitization. Currently, solid organ pancreas transplant is the only remaining surgical option following failed islet transplantation in the United States; however, the immunologic impact of repeated exposure to donor antigens on subsequent pancreas transplantation is unclear. We describe a case series of seven patients undergoing solid organ pancreas transplant following islet graft failure with long-term follow-up of pancreatic graft survival and renal function. Despite highly variable panel reactive antibody levels prior to pancreas transplant (mean 27 ± 35%), all seven patients achieved stable and durable insulin independence with a mean follow-up of 6.7 years. Mean hemoglobin A1c values improved significantly from postislet, prepancreas levels (mean 8.1 ± 1.5%) to postpancreas levels (mean 5.3 ± 0.1%; p = 0.0022). Three patients experienced acute rejection episodes that were successfully managed with thymoglobulin and methylprednisolone, and none of these preuremic type 1 diabetic recipients developed stage 4 or 5 chronic kidney disease postoperatively. These results support pancreas-after-islet transplantation with aggressive immunosuppression and protocol biopsies as a viable strategy to restore insulin independence after islet graft failure. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  7. Hormone-sensitive lipase deficiency suppresses insulin secretion from pancreatic islets of Lepob/ob mice

    International Nuclear Information System (INIS)

    Sekiya, Motohiro; Yahagi, Naoya; Tamura, Yoshiaki; Okazaki, Hiroaki; Igarashi, Masaki; Ohta, Keisuke; Takanashi, Mikio; Kumagai, Masayoshi; Takase, Satoru; Nishi, Makiko; Takeuchi, Yoshinori; Izumida, Yoshihiko; Kubota, Midori; Ohashi, Ken; Iizuka, Yoko; Yagyu, Hiroaki; Gotoda, Takanari; Nagai, Ryozo; Shimano, Hitoshi; Yamada, Nobuhiro

    2009-01-01

    It has long been a matter of debate whether the hormone-sensitive lipase (HSL)-mediated lipolysis in pancreatic β-cells can affect insulin secretion through the alteration of lipotoxicity. We generated mice lacking both leptin and HSL (Lep ob/ob /HSL -/- ) and explored the role of HSL in pancreatic β-cells in the setting of obesity. Lep ob/ob /HSL -/- developed elevated blood glucose levels and reduced plasma insulin levels compared with Lep ob/ob /HSL +/+ in a fed state, while the deficiency of HSL did not affect glucose homeostasis in Lep +/+ background. The deficiency of HSL exacerbated the accumulation of triglycerides in Lep ob/ob islets, leading to reduced glucose-stimulated insulin secretion. The deficiency of HSL also diminished the islet mass in Lep ob/ob mice due to decreased cell proliferation. In conclusion, HSL affects insulin secretary capacity especially in the setting of obesity.

  8. Construction of RNAi lentiviral vector targeting mouse Islet-1 gene

    Directory of Open Access Journals (Sweden)

    Shen-shen ZHI

    2011-02-01

    Full Text Available Objective To construct and select RNAi lentiviral vectors that can silence mouse Islet-1 gene effectively.Methods Three groups of RNAi-target of mouse Islet-1 gene were designed,and corresponding shRNA oligo(sh1,sh2 and sh3 were synthesized,and then they were respectively inserted to the PLVTHM vector that had been digested by endonuclease.Agarose gel electrophoresis and sequencing were used to select and indentify the positive clones.The positive clones were extracted and then mixed with E.coli to amplify positive clones.The amplified clones were then infected into 293T along with the other 3 helper plasmids to produce lentiviral vector.After the construction of the lentiviral vector,plaque formation test was performed to determine the titer of lentiviral vector.The lentiviral vectors were then infected into C3H10T1/2 cells.The transfect efficiency of the lentiviral vectors was determined with flow cytometry with detection of green fluorescent protein(GFP.Q-PCR was employed to detect the RNAi efficiency of the lentiviral vectors.Results Agarose gel electrophoresis analysis showed that the clones with right gene at the target size were successfully established;gene sequencing showed that the right DNA fragments had been inserted;plaque formation test showed that the titer of the virus solution was 3.87×108TU/ml;the transfect efficiency of the lentiviral vector infected into C3H10T1/2 cells was 90.36%.All the 3 groups of shRNA targets(sh1,sh2 and sh3 showed an inhibitory effect on Islet-1 gene,and the sh1 showed the highest inhibitory effect(76.8%,as compared with that of normal cells(P < 0.05.Conclusion The RNAi lentiviral vector that can effectively silence the mouse Islet-1 gene has been constructed successfully,which may lay a foundation for further investigation of Islet-1 gene.

  9. Diabetes Is Reversed in a Murine Model by Marginal Mass Syngeneic Islet Transplantation Using a Subcutaneous Cell Pouch Device.

    Science.gov (United States)

    Pepper, Andrew R; Pawlick, Rena; Gala-Lopez, Boris; MacGillivary, Amanda; Mazzuca, Delfina M; White, David J G; Toleikis, Philip M; Shapiro, A M James

    2015-11-01

    Islet transplantation is a successful β-cell replacement therapy for selected patients with type 1 diabetes mellitus. Although high rates of early insulin independence are achieved routinely, long-term function wanes over time. Intraportal transplantation is associated with procedural risks, requires multiple donors, and does not afford routine biopsy. Stem cell technologies may require potential for retrievability, and graft removal by hepatectomy is impractical. There is a clear clinical need for an alternative, optimized transplantation site. The subcutaneous space is a potential substitute, but transplantation of islets into this site has routinely failed to reverse diabetes. However, an implanted device, which becomes prevascularized before transplantation, may alter this equation. Syngeneic mouse islets were transplanted subcutaneously within Sernova Corp's Cell Pouch (CP). All recipients were preimplanted with CPs 4 weeks before diabetes induction and transplantation. After transplantation, recipients were monitored for glycemic control and glucose tolerance. Mouse islets transplanted into the CP routinely restored glycemic control with modest delay and responded well to glucose challenge, comparable to renal subcapsular islet grafts, despite a marginal islet dose, and normoglycemia was maintained until graft explantation. In contrast, islets transplanted subcutaneously alone failed to engraft. Islets within CPs stained positively for insulin, glucagon, and microvessels. The CP is biocompatible, forms an environment suitable for islet engraftment, and offers a potential alternative to the intraportal site for islet and future stem cell therapies.

  10. Neurotrophin Signaling Is Required for Glucose-Induced Insulin Secretion.

    Science.gov (United States)

    Houtz, Jessica; Borden, Philip; Ceasrine, Alexis; Minichiello, Liliana; Kuruvilla, Rejji

    2016-11-07

    Insulin secretion by pancreatic islet β cells is critical for glucose homeostasis, and a blunted β cell secretory response is an early deficit in type 2 diabetes. Here, we uncover a regulatory mechanism by which glucose recruits vascular-derived neurotrophins to control insulin secretion. Nerve growth factor (NGF), a classical trophic factor for nerve cells, is expressed in pancreatic vasculature while its TrkA receptor is localized to islet β cells. High glucose rapidly enhances NGF secretion and increases TrkA phosphorylation in mouse and human islets. Tissue-specific deletion of NGF or TrkA, or acute disruption of TrkA signaling, impairs glucose tolerance and insulin secretion in mice. We show that internalized TrkA receptors promote insulin granule exocytosis via F-actin reorganization. Furthermore, NGF treatment augments glucose-induced insulin secretion in human islets. These findings reveal a non-neuronal role for neurotrophins and identify a new regulatory pathway in insulin secretion that can be targeted to ameliorate β cell dysfunction. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Advances and Challenges in Islet Transplantation: Islet Procurement Rates and Lessons Learned from Suboptimal Islet Transplantation

    OpenAIRE

    Annette Plesner; C. Bruce Verchere

    2011-01-01

    The initial step in successful islet transplantation is procurement of healthy donor islets. Given the limited number of donor pancreata selected for islet isolation and that islets from multiple donors are typically required to obtain insulin independence, it is critical to improve pancreas procurement rates and yield of islets for transplantation. Islets are delicate microorgans that are susceptible to apoptosis, hypoxia, and ischemia during isolation, culture, and the peritransplant period...

  12. Effect Of Aqueous And Hydroalcoholic Extract Of Beberis Vulgaris On Insulin Secretion From Islets Of Langerhans Isolated From Male Mice

    Directory of Open Access Journals (Sweden)

    A Ahangarpour

    2012-10-01

    Full Text Available Background & Aim: considering the use of Beberis vulgaris in traditional medicine as a blood sugar depressant, in this study, the effect of Beberis vulgaris extracts were investigated on the level of insulin secretion from islets isolated of langerhans in male mice. Methods: This experimental study was carried out on 90 adult male mice, NMARI strains weighing 20-25 g. Pancreatic islets from normal mice were isolated by collagenase digestion method. Then the aqueous and hydro-alcoholic extract of Beberis vulgaris at 0.05, 0.1, and 1 mg/ml concentrations and glyburide at 1 and 10 μM concentrations were applied on islets isolated in three different concentration of glucose solution (2.8, 5.6 and 16.7 mM. Insulin secretion from hand-picked islets were evaluated in the static incubation system. The level of Insulin secretion was measured by the ELISA insulin kit. Data were analyzed with variance analysis. Results: Insulin secretion was significantly increased at 16.7 mM glucose concentration in comparison with 2.8 and 5.6 mM glucose concentration (p<0.05. Incubation of pancreatic islets isolated at 2.8 and 5.6 mM glucose concentration and low concentrations of extract (0.05 and 0.1mg/ml significantly increased the insulin secretion (p<0.05. Glyburide at 10 μM concentration was more effective than aqueous and hydro alcoholic extract of Beberis vulgaris at 16.7 mM glucose. Conclusion: The present study supported the anti-diabetic effect of Beberis vulgaris extracts in vitro with low glucose concentration and it suggests that one of the anti diabetic mechanisms of this plant is via pancreatic islets.

  13. Non-invasive, in vitro analysis of islet insulin production enabled by an optical porous silicon biosensor.

    Science.gov (United States)

    Chhasatia, Rinku; Sweetman, Martin J; Harding, Frances J; Waibel, Michaela; Kay, Tom; Thomas, Helen; Loudovaris, Thomas; Voelcker, Nicolas H

    2017-05-15

    A label-free porous silicon (pSi) based, optical biosensor, using both an antibody and aptamer bioreceptor motif has been developed for the detection of insulin. Two parallel biosensors were designed and optimised independently, based on each bioreceptor. Both bioreceptors were covalently attached to a thermally hydrosilylated pSi surface though amide coupling, with unreacted surface area rendered stable and low fouling by incorporation of PEG moieties. The insulin detection ability of each biosensor was determined using interferometric reflectance spectroscopy, using a range of different media both with and without serum. Sensing performance was compared in terms of response value, response time and limit of detection (LOD) for each platform. In order to demonstrate the capability of the best performing biosensor to detect insulin from real samples, an in vitro investigation with the aptamer-modified surface was performed. This biosensor was exposed to buffer conditioned by glucose-stimulated human islets, with the result showing a positive response and a high degree of selectivity towards insulin capture. The obtained results correlated well with the ELISA used in the clinic for assaying glucose-stimulated insulin release from donor islets. We anticipate that this type of sensor can be applied as a rapid point-of-use biosensor to assess the quality of donor islets in terms of their insulin production efficiency, prior to transplantation. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Relationship between insulin release and 65zinc efflux from rat pancreatic islets maintained in tissue culture

    International Nuclear Information System (INIS)

    Formby, B.; Schmid-Formby, F.; Grodsky, G.M.

    1984-01-01

    In short-term batch-incubation or perfusion experiments, we studied insulin release and associated 65 Zn efflux from rat pancreatic islets loaded with 65 Zn by 24-h tissue culture in low-glucose medium. The fractional basal insulin release and 65 Zn efflux were 0.4% and 3% of total content/h/islet, respectively. Thus, basal 65 Zn efflux was much greater than that to be accounted for if zinc was released proportionally with insulin release only; extragranular zinc flux was suggested. Two millimolar glucose, with or without 1 mM 3-isobutyl-1-methylxanthine (IBMX), affected neither insulin release nor associated 65 Zn efflux. Twenty-five millimolar glucose produced a significant threefold increase in insulin release above baseline, but somewhat decreased 65 Zn efflux at marginal significance. Glucose (25 mM) plus 1 mM IBMX provoked a high increase in insulin release and an associated 30% increase in fractional 65 Zn efflux over basal. Calculations based on previous estimations of 65 Zn distribution and equilibrium with islet zinc indicated that molar zinc efflux was more than sufficient to account for a 2-zinc-insulin hexamer. L-Leucine (2 or 20 mM) plus 1 mM IBMX caused far greater 65 Zn efflux for the amount of insulin released, indicating additional 65 Zn mobilization not directly related to insulin secretion. To evaluate 65 Zn efflux during inhibited insulin secretion, batch incubations were performed in 100% D 2 O or at 27 degrees C, conditions that inhibited insulin release stimulated by high glucose plus IBMX. These agents decreased the 65 Zn efflux far below the basal value (35% and 50%, respectively) and greater than could be accounted for by the attendent inhibition of insulin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Electrofusion of mesenchymal stem cells and islet cells for diabetes therapy: a rat model.

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    Goichi Yanai

    Full Text Available Islet transplantation is a minimally invasive treatment for severe diabetes. However, it often requires multiple donors to accomplish insulin-independence and the long-term results are not yet satisfying. Therefore, novel ways to overcome these problems have been explored. Isolated islets are fragile and susceptible to pro-apoptotic factors and poorly proliferative. In contrast, mesenchymal stem cells (MSCs are highly proliferative, anti-apoptotic and pluripotent to differentiate toward various cell types, promote angiogenesis and modulate inflammation, thereby studied as an enhancer of islet function and engraftment. Electrofusion is an efficient method of cell fusion and nuclear reprogramming occurs in hybrid cells between different cell types. Therefore, we hypothesized that electrofusion between MSC and islet cells may yield robust islet cells for diabetes therapy. We establish a method of electrofusion between dispersed islet cells and MSCs in rats. The fusion cells maintained glucose-responsive insulin release for 20 days in vitro. Renal subcapsular transplantation of fusion cells prepared from suboptimal islet mass (1,000 islets that did not correct hyperglycemia even if co-transplanted with MSCs, caused slow but consistent lowering of blood glucose with significant weight gain within the observation period in streptozotocin-induced diabetic rats. In the fusion cells between rat islet cells and mouse MSCs, RT-PCR showed new expression of both rat MSC-related genes and mouse β-cell-related genes, indicating bidirectional reprogramming of both β-cell and MSCs nuclei. Moreover, decreased caspase3 expression and new expression of Ki-67 in the islet cell nuclei suggested alleviated apoptosis and gain of proliferative capability, respectively. These results show that electrofusion between MSCs and islet cells yield special cells with β-cell function and robustness of MSCs and seems feasible for novel therapeutic strategy for diabetes

  16. Adipose stem cells from chronic pancreatitis patients improve mouse and human islet survival and function.

    Science.gov (United States)

    Song, Lili; Sun, Zhen; Kim, Do-Sung; Gou, Wenyu; Strange, Charlie; Dong, Huansheng; Cui, Wanxing; Gilkeson, Gary; Morgan, Katherine A; Adams, David B; Wang, Hongjun

    2017-08-30

    Chronic pancreatitis has surgical options including total pancreatectomy to control pain. To avoid surgical diabetes, the explanted pancreas can have islets harvested and transplanted. Immediately following total pancreatectomy with islet autotransplantation (TP-IAT), many islet cells die due to isolation and transplantation stresses. The percentage of patients remaining insulin free after TP-IAT is therefore low. We determined whether cotransplantation of adipose-derived mesenchymal stem cells (ASCs) from chronic pancreatitis patients (CP-ASCs) would protect islets after transplantation. In a marginal mass islet transplantation model, islets from C57BL/6 mice were cotransplanted with CP-ASCs into syngeneic streptozotocin-treated diabetic mice. Treatment response was defined by the percentage of recipients reaching normoglycemia, and by the area under the curve for glucose and c-peptide in a glucose tolerance test. Macrophage infiltration, β-cell apoptosis, and islet graft vasculature were measured in transplanted islet grafts by immunohistochemistry. mRNA expression profiling of 84 apoptosis-related genes in islet grafts transplanted alone or with CP-ASCs was measured by the RT 2 Profiler™ Apoptosis PCR Array. The impact of insulin-like growth factor-1 (IGF-1) on islet apoptosis was determined in islets stimulated with cytokines (IL-1β and IFN-γ) in the presence and absence of CP-ASC conditioned medium. CP-ASC-treated mice were more often normoglycemic compared to mice receiving islets alone. ASC cotransplantation reduced macrophage infiltration, β-cell death, suppressed expression of TNF-α and Bcl-2 modifying factor (BMF), and upregulated expressions of IGF-1 and TNF Receptor Superfamily Member 11b (TNFRSF11B) in islet grafts. Islets cultured in conditioned medium from CP-ASCs showed reduced cell death. This protective effect was diminished when IGF-1 was blocked in the conditioned medium by the anti-IGF-1 antibody. Cotransplantation of islets with ASCs

  17. Cellular islet autoimmunity associates with clinical outcome of islet cell transplantation.

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    Volkert A L Huurman

    2008-06-01

    Full Text Available Islet cell transplantation can cure type 1 diabetes (T1D, but only a minority of recipients remains insulin-independent in the following years. We tested the hypothesis that allograft rejection and recurrent autoimmunity contribute to this progressive loss of islet allograft function.Twenty-one T1D patients received cultured islet cell grafts prepared from multiple donors and transplanted under anti-thymocyte globulin (ATG induction and tacrolimus plus mycophenolate mofetil (MMF maintenance immunosuppression. Immunity against auto- and alloantigens was measured before and during one year after transplantation. Cellular auto- and alloreactivity was assessed by lymphocyte stimulation tests against autoantigens and cytotoxic T lymphocyte precursor assays, respectively. Humoral reactivity was measured by auto- and alloantibodies. Clinical outcome parameters--including time until insulin independence, insulin independence at one year, and C-peptide levels over one year--remained blinded until their correlation with immunological parameters. All patients showed significant improvement of metabolic control and 13 out of 21 became insulin-independent. Multivariate analyses showed that presence of cellular autoimmunity before and after transplantation is associated with delayed insulin-independence (p = 0.001 and p = 0.01, respectively and lower circulating C-peptide levels during the first year after transplantation (p = 0.002 and p = 0.02, respectively. Seven out of eight patients without pre-existent T-cell autoreactivity became insulin-independent, versus none of the four patients reactive to both islet autoantigens GAD and IA-2 before transplantation. Autoantibody levels and cellular alloreactivity had no significant association with outcome.In this cohort study, cellular islet-specific autoimmunity associates with clinical outcome of islet cell transplantation under ATG-tacrolimus-MMF immunosuppression. Tailored immunotherapy targeting cellular

  18. Ca2+ controls slow NAD(P)H oscillations in glucose-stimulated mouse pancreatic islets

    DEFF Research Database (Denmark)

    Luciani, Dan Seriano; Misler, S.; Polonsky, K.S.

    2006-01-01

    Exposure of pancreatic islets of Langerhans to physiological concentrations of glucose leads to secretion of insulin in an oscillatory pattern. The oscillations in insulin secretion are associated with oscillations in cytosolic Ca2+ concentration ([Ca2+](c)). Evidence suggests that the oscillatio...

  19. High glucose suppresses human islet insulin biosynthesis by inducing miR-133a leading to decreased polypyrimidine tract binding protein-expression.

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    Rikard G Fred

    Full Text Available BACKGROUND: Prolonged periods of high glucose exposure results in human islet dysfunction in vitro. The underlying mechanisms behind this effect of high glucose are, however, unknown. The polypyrimidine tract binding protein (PTB is required for stabilization of insulin mRNA and the PTB mRNA 3'-UTR contains binding sites for the microRNA molecules miR-133a, miR-124a and miR-146. The aim of this study was therefore to investigate whether high glucose increased the levels of these three miRNAs in association with lower PTB levels and lower insulin biosynthesis rates. METHODOLOGY/PRINCIPAL FINDINGS: Human islets were cultured for 24 hours in the presence of low (5.6 mM or high glucose (20 mM. Islets were also exposed to sodium palmitate or the proinflammatory cytokines IL-1beta and IFN-gamma, since saturated free fatty acids and cytokines also cause islet dysfunction. RNA was then isolated for real-time RT-PCR analysis of miR-133a, miR-124a, miR-146, insulin mRNA and PTB mRNA contents. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. Synthetic miR-133a precursor and inhibitor were delivered to dispersed islet cells by lipofection, and PTB was analyzed by immunoblotting following culture at low or high glucose. Culture in high glucose resulted in increased islet contents of miR-133a and reduced contents of miR-146. Cytokines increased the contents of miR-146. The insulin and PTB mRNA contents were unaffected by high glucose. However, both PTB protein levels and insulin biosynthesis rates were decreased in response to high glucose. The miR-133a inhibitor prevented the high glucose-induced decrease in PTB and insulin biosynthesis, and the miR-133a precursor decreased PTB levels and insulin biosynthesis similarly to high glucose. CONCLUSION: Prolonged high-glucose exposure down-regulates PTB levels and insulin biosynthesis rates in human islets by increasing miR-133a levels. We propose that this mechanism

  20. Islet Transplantation Provides Superior Glycemic Control With Less Hypoglycemia Compared With Continuous Subcutaneous Insulin Infusion or Multiple Daily Insulin Injections.

    Science.gov (United States)

    Holmes-Walker, Deborah Jane; Gunton, Jenny E; Hawthorne, Wayne; Payk, Marlene; Anderson, Patricia; Donath, Susan; Loudovaris, Tom; Ward, Glenn M; Kay, Thomas Wh; OʼConnell, Philip J

    2017-06-01

    The aim was to compare efficacy of multiple daily injections (MDI), continuous subcutaneous insulin infusion (CSII) and islet transplantation to reduce hypoglycemia and glycemic variability in type 1 diabetes subjects with severe hypoglycemia. This was a within-subject, paired comparison of MDI and CSII and CSII with 12 months postislet transplantation in 10 type 1 diabetes subjects referred with severe hypoglycemia, suitable for islet transplantation. Individuals were assessed with HbA1c, Edmonton Hypoglycemia Score (HYPOscore), continuous glucose monitoring (CGM) and in 8 subjects measurements of glucose variability using standard deviation of glucose (SD glucose) from CGM and continuous overlapping net glycemic action using a 4 hour interval (CONGA4). After changing from MDI to CSII before transplantation, 10 subjects reduced median HYPOscore from 2028 to 1085 (P transplantation, there were significant reductions in all baseline parameters versus CSII, respectively, HbA1c (6.4% cf 8.2%), median HYPOscore (0 cf 1085), mean glucose (7.1 cf 8.6 mmol L), SD glucose (1.7 cf 3.2 mmol/L), and CONGA4 (1.6 cf 3.0). In subjects with severe hypoglycemia suitable for islet transplantation, CSII decreased hypoglycemia frequency and glycemic variability compared with MDI whereas islet transplantation resolved hypoglycemia and further improved glycemic variability regardless of insulin independence.

  1. Effects of the beta-carbolines, harmane and pinoline, on insulin secretion from isolated human islets of Langerhans.

    Science.gov (United States)

    Cooper, E Jane; Hudson, Alan L; Parker, Christine A; Morgan, Noel G

    2003-12-15

    It is well known that certain imidazoline compounds can stimulate insulin secretion and this has been attributed to the activation of imidazoline I(3) binding sites in the pancreatic beta-cell. Recently, it has been proposed that beta-carbolines may be endogenous ligands having activity at imidazoline sites and we have, therefore, studied the effects of beta-carbolines on insulin secretion. The beta-carbolines harmane, norharmane and pinoline increased insulin secretion two- to threefold from isolated human islets of Langerhans. The effects of harmane and pinoline were dose-dependent (EC(50): 5 and 25 microM, respectively) and these agents also blocked the inhibitory effects of the potassium channel agonist, diazoxide, on glucose-induced insulin release. Stimulation of insulin secretion by harmane was glucose-dependent but, unlike the imidazoline I(3) receptor agonist efaroxan, it increased the rate of insulin release beyond that elicited by 20 mM glucose (20 mM glucose alone: 253+/-34% vs. basal; 20 mM glucose plus 100 microM harmane: 327+/-15%; P<0.01). Stimulation of insulin secretion by harmane was attenuated by the imidazoline I(3) receptor antagonist KU14R (2 (2-ethyl 2,3-dihydro-2-benzofuranyl)-2-imidazole) and was reduced when islets were treated with efaroxan for 18 h, prior to the addition of harmane. The results reveal that beta-carbolines can potentiate the rate of insulin secretion from human islets and suggest that these agents may be useful prototypes for the development of novel insulin secretagogues.

  2. Combined lipidomic and proteomic analysis of isolated human islets exposed to palmitate reveals time-dependent changes in insulin secretion and lipid metabolism.

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    Kirsten Roomp

    Full Text Available Studies on the pathophysiology of type 2 diabetes mellitus (T2DM have linked the accumulation of lipid metabolites to the development of beta-cell dysfunction and impaired insulin secretion. In most in vitro models of T2DM, rodent islets or beta-cell lines are used and typically focus is on specific cellular pathways or organs. Our aim was to, firstly, develop a combined lipidomics and proteomics approach for lipotoxicity in isolated human islets and, secondly, investigate if the approach could delineate novel and/ or confirm reported mechanisms of lipotoxicity. To this end isolated human pancreatic islets, exposed to chronically elevated palmitate concentrations for 0, 2 and 7 days, were functionally characterized and their levels of multiple targeted lipid and untargeted protein species determined. Glucose-stimulated insulin secretion from the islets increased on day 2 and decreased on day 7. At day 7 islet insulin content decreased and the proinsulin to insulin content ratio doubled. Amounts of cholesterol, stearic acid, C16 dihydroceramide and C24:1 sphingomyelin, obtained from the lipidomic screen, increased time-dependently in the palmitate-exposed islets. The proteomic screen identified matching changes in proteins involved in lipid biosynthesis indicating up-regulated cholesterol and lipid biosynthesis in the islets. Furthermore, proteins associated with immature secretory granules were decreased when palmitate exposure time was increased despite their high affinity for cholesterol. Proteins associated with mature secretory granules remained unchanged. Pathway analysis based on the protein and lipid expression profiles implicated autocrine effects of insulin in lipotoxicity. Taken together the study demonstrates that combining different omics approaches has potential in mapping of multiple simultaneous cellular events. However, it also shows that challenges exist for effectively combining lipidomics and proteomics in primary cells. Our

  3. Decreased 11β-Hydroxysteroid Dehydrogenase 1 Level and Activity in Murine Pancreatic Islets Caused by Insulin-Like Growth Factor I Overexpression.

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    Subrata Chowdhury

    Full Text Available We have reported a high expression of IGF-I in pancreatic islet β-cells of transgenic mice under the metallothionein promoter. cDNA microarray analysis of the islets revealed that the expression of 82 genes was significantly altered compared to wild-type mice. Of these, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1, which is responsible for the conversion of inert cortisone (11-dehydrocorticosterone, DHC in rodents to active cortisol (corticosterone in the liver and adipose tissues, has not been identified previously as an IGF-I target in pancreatic islets. We characterized the changes in its protein level, enzyme activity and glucose-stimulated insulin secretion. In freshly isolated islets, the level of 11β-HSD1 protein was significantly lower in MT-IGF mice. Using dual-labeled immunofluorescence, 11β-HSD1 was observed exclusively in glucagon-producing, islet α-cells but at a lower level in transgenic vs. wild-type animals. MT-IGF islets also exhibited reduced enzymatic activities. Dexamethasone (DEX and DHC inhibited glucose-stimulated insulin secretion from freshly isolated islets of wild-type mice. In the islets of MT-IGF mice, 48-h pre-incubation of DEX caused a significant decrease in insulin release, while the effect of DHC was largely blunted consistent with diminished 11β-HSD1 activity. In order to establish the function of intracrine glucocorticoids, we overexpressed 11β-HSD1 cDNA in MIN6 insulinoma cells, which together with DHC caused apoptosis and a significant decrease in proliferation. Both effects were abolished with the treatment of an 11β-HSD1 inhibitor. Our results demonstrate an inhibitory effect of IGF-I on 11β-HSD1 expression and activity within the pancreatic islets, which may mediate part of the IGF-I effects on cell proliferation, survival and insulin secretion.

  4. Pancreatic islet transplantation

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    Corrêa-Giannella Maria

    2009-09-01

    Full Text Available Abstract Background No formulation of exogenous insulin available to date has yet been able to mimic the physiological nictemeral rhythms of this hormone, and despite all engineering advancements, the theoretical proposal of developing a mechanical replacement for pancreatic β cell still has not been reached. Thus, the replacement of β cells through pancreas and pancreatic islet transplantation are the only concrete alternatives for re-establishing the endogenous insulin secretion in type 1 diabetic patients. Since only 1 to 1.5% of the pancreatic mass corresponds to endocrine tissue, pancreatic islets transplantation arises as a natural alternative. Data from the International Islet Transplant Registry (ITR from 1983 to December 2000 document a total of 493 transplants performed around the world, with progressively worse rates of post-transplant insulin independence. In 2000, the "Edmonton Protocol" introduced several modifications to the transplantation procedure, such as the use of a steroid-free immunosuppression regimen and transplantation of a mean islet mass of 11,000 islet equivalents per kilogram, which significantly improved 1-year outcomes. Although the results of a 5-year follow-up in 65 patients demonstrated improvement in glycemic instability in a significant portion of them, only 7.5% of the patients have reached insulin independence, indicating the need of further advances in the preservation of the function of transplanted islet. In addition to the scarcity of organs available for transplantation, islets transplantation still faces major challenges, specially those related to cell loss during the process of islet isolation and the losses related to the graft site, apoptosis, allorejection, autoimmunity, and immunosuppression. The main strategies to optimize islet transplantation aim at improving all these aspects. Conclusion Human islet transplantation should be regarded as an intervention that can decrease the frequency of

  5. Glucose-Dependent Insulin Secretion in Pancreatic β-Cell Islets from Male Rats Requires Ca2+ Release via ROS-Stimulated Ryanodine Receptors.

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    Paola Llanos

    Full Text Available Glucose-stimulated insulin secretion (GSIS from pancreatic β-cells requires an increase in intracellular free Ca2+ concentration ([Ca2+]. Glucose uptake into β-cells promotes Ca2+ influx and reactive oxygen species (ROS generation. In other cell types, Ca2+ and ROS jointly induce Ca2+ release mediated by ryanodine receptor (RyR channels. Therefore, we explored here if RyR-mediated Ca2+ release contributes to GSIS in β-cell islets isolated from male rats. Stimulatory glucose increased islet insulin secretion, and promoted ROS generation in islets and dissociated β-cells. Conventional PCR assays and immunostaining confirmed that β-cells express RyR2, the cardiac RyR isoform. Extended incubation of β-cell islets with inhibitory ryanodine suppressed GSIS; so did the antioxidant N-acetyl cysteine (NAC, which also decreased insulin secretion induced by glucose plus caffeine. Inhibitory ryanodine or NAC did not affect insulin secretion induced by glucose plus carbachol, which engages inositol 1,4,5-trisphosphate receptors. Incubation of islets with H2O2 in basal glucose increased insulin secretion 2-fold. Inhibitory ryanodine significantly decreased H2O2-stimulated insulin secretion and prevented the 4.5-fold increase of cytoplasmic [Ca2+] produced by incubation of dissociated β-cells with H2O2. Addition of stimulatory glucose or H2O2 (in basal glucose to β-cells disaggregated from islets increased RyR2 S-glutathionylation to similar levels, measured by a proximity ligation assay; in contrast, NAC significantly reduced the RyR2 S-glutathionylation increase produced by stimulatory glucose. We propose that RyR2-mediated Ca2+ release, induced by the concomitant increases in [Ca2+] and ROS produced by stimulatory glucose, is an essential step in GSIS.

  6. Label-free detection of insulin and glucagon within human islets of Langerhans using Raman spectroscopy.

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    Janneke Hilderink

    Full Text Available Intrahepatic transplantation of donor islets of Langerhans is a promising therapy for patients with type 1 diabetes. It is of critical importance to accurately monitor islet quality before transplantation, which is currently done by standard histological methods that are performed off-line and require extensive sample preparation. As an alternative, we propose Raman spectroscopy which is a non-destructive and label-free technique that allows continuous real-time monitoring of the tissue to study biological changes as they occur. By performing Raman spectroscopic measurements on purified insulin and glucagon, we showed that the 520 cm(-1 band assigned to disulfide bridges in insulin, and the 1552 cm(-1 band assigned to tryptophan in glucagon are mutually exclusive and could therefore be used as indirect markers for the label-free distinction between both hormones. High-resolution hyperspectral Raman imaging for these bands showed the distribution of disulfide bridges and tryptophan at sub-micrometer scale, which correlated with the location of insulin and glucagon as revealed by conventional immunohistochemistry. As a measure for this correlation, quantitative analysis was performed comparing the Raman images with the fluorescence images, resulting in Dice coefficients (ranging between 0 and 1 of 0.36 for insulin and 0.19 for glucagon. Although the use of separate microscope systems with different spatial resolution and the use of indirect Raman markers cause some image mismatch, our findings indicate that Raman bands for disulfide bridges and tryptophan can be used as distinctive markers for the label-free detection of insulin and glucagon in human islets of Langerhans.

  7. Engraftment Site and Effectiveness of the Pan-Caspase Inhibitor F573 to Improve Engraftment in Mouse and Human Islet Transplantation in Mice.

    Science.gov (United States)

    Pepper, Andrew R; Bruni, Antonio; Pawlick, Rena; Wink, John; Rafiei, Yasmin; Gala-Lopez, Boris; Bral, Mariusz; Abualhassan, Nasser; Kin, Tatsuya; Shapiro, A M James

    2017-10-01

    Islet transplantation is an effective therapy in type 1 diabetes and recalcitrant hypoglycemia. However, there is an ongoing need to circumvent islet loss posttransplant. We explore herein the potential of the pan-caspase inhibitor F573 to mitigate early apoptosis-mediated islet death within portal and extrahepatic portal sites in mice. Mouse or human islets were cultured in standard media ±100 μM F573 and subsequently assessed for viability and apoptosis via terminal deoxynucleotidyl transferase dUTP nick end labeling staining and caspase-3 activation. Diabetic mice were transplanted with syngeneic islets placed under the kidney capsule (KC) or into the subcutaneous deviceless (DL) site at a marginal islet dose (150 islets), or into the portal vein (PV) at a full dose (500 islets). Human islets were transplanted under the KC of diabetic immunodeficient mice at a marginal dose (500 islet equivalents). Islets were cultured in the presence of F573, and F573 was administered subcutaneously on days 0 to 5 posttransplant. Control mice were transplanted with nontreated islets and were injected with saline. Graft function was measured by nonfasting blood glucose and glucose tolerance testing. F573 markedly reduced human and mouse islet apoptosis after in vitro culture (P islet function when transplanted under the KC (P islet marginal KC transplants. Conversely, F573 significantly improved mouse islet engraftment in the PV and DL site (P islet apoptosis and improves engraftment most effectively in the portal and DL subcutaneous sites.

  8. PDX-1 Is a Therapeutic Target for Pancreatic Cancer, Insulinoma and Islet Neoplasia Using a Novel RNA Interference Platform

    Science.gov (United States)

    Liu, Shi-He; Rao, Donald D.; Nemunaitis, John; Senzer, Neil; Zhou, Guisheng; Dawson, David; Gingras, Marie-Claude; Wang, Zhaohui; Gibbs, Richard; Norman, Michael; Templeton, Nancy S.; DeMayo, Francesco J.; O'Malley, Bert; Sanchez, Robbi; Fisher, William E.; Brunicardi, F. Charles

    2012-01-01

    Pancreatic and duodenal homeobox-1 (PDX-1) is a transcription factor that regulates insulin expression and islet maintenance in the adult pancreas. Our recent studies demonstrate that PDX-1 is an oncogene for pancreatic cancer and is overexpressed in pancreatic cancer. The purpose of this study was to demonstrate that PDX-1 is a therapeutic target for both hormonal symptoms and tumor volume in mouse models of pancreatic cancer, insulinoma and islet neoplasia. Immunohistochemistry of human pancreatic and islet neoplasia specimens revealed marked PDX-1 overexpression, suggesting PDX-1 as a “drugable” target within these diseases. To do so, a novel RNA interference effector platform, bifunctional shRNAPDX-1, was developed and studied in mouse and human cell lines as well as in mouse models of pancreatic cancer, insulinoma and islet neoplasia. Systemic delivery of bi-shRNAhumanPDX-1 lipoplexes resulted in marked reduction of tumor volume and improved survival in a human pancreatic cancer xenograft mouse model. bi-shRNAmousePDX-1 lipoplexes prevented death from hyperinsulinemia and hypoglycemia in an insulinoma mouse model. shRNAmousePDX-1 lipoplexes reversed hyperinsulinemia and hypoglycemia in an immune-competent mouse model of islet neoplasia. PDX-1 was overexpressed in pancreatic neuroendocrine tumors and nesidioblastosis. These data demonstrate that PDX-1 RNAi therapy controls hormonal symptoms and tumor volume in mouse models of pancreatic cancer, insulinoma and islet neoplasia, therefore, PDX-1 is a potential therapeutic target for these pancreatic diseases. PMID:22905092

  9. A review of piscine islet xenotransplantation using wild-type tilapia donors and the production of transgenic tilapia expressing a "humanized" tilapia insulin.

    Science.gov (United States)

    Wright, James R; Yang, Hua; Hyrtsenko, Olga; Xu, Bao-You; Yu, Weiming; Pohajdak, Bill

    2014-01-01

    Most islet xenotransplantation laboratories have focused on porcine islets, which are both costly and difficult to isolate. Teleost (bony) fish, such as tilapia, possess macroscopically visible distinct islet organs called Brockmann bodies which can be inexpensively harvested. When transplanted into diabetic nude mice, tilapia islets maintain long-term normoglycemia and provide human-like glucose tolerance profiles. Like porcine islets, when transplanted into euthymic mice, they are rejected in a CD4 T-cell-dependent manner. However, unlike pigs, tilapia are so phylogenetically primitive that their cells do not express α(1,3)Gal and, because tilapia are highly evolved to live in warm stagnant waters nearly devoid of dissolved oxygen, their islet cells are exceedingly resistant to hypoxia, making them ideal for transplantation within encapsulation devices. Encapsulation, especially when combined with co-stimulatory blockade, markedly prolongs tilapia islet xenograft survival in small animal recipients, and a collaborator has shown function in diabetic cynomolgus monkeys. In anticipation of preclinical xenotransplantation studies, we have extensively characterized tilapia islets (morphology, embryologic development, cell biology, peptides, etc.) and their regulation of glucose homeostasis. Because tilapia insulin differs structurally from human insulin by 17 amino acids, we have produced transgenic tilapia whose islets stably express physiological levels of humanized insulin and have now bred these to homozygosity. These transgenic fish can serve as a platform for further development into a cell therapy product for diabetes. © 2014 The Authors. Xenotransplantation Published by John Wiley & Sons Ltd.

  10. Human pancreatic islet-derived extracellular vesicles modulate insulin expression in 3D-differentiating iPSC clusters.

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    Diana Ribeiro

    Full Text Available It has been suggested that extracellular vesicles (EVs can mediate crosstalk between hormones and metabolites within pancreatic tissue. However, the possible effect of pancreatic EVs on stem cell differentiation into pancreatic lineages remains unknown. Herein, human islet-derived EVs (h-Islet-EVs were isolated, characterized and subsequently added to human induced pluripotent stem cell (iPSC clusters during pancreatic differentiation. The h-islet-EVs had a mean size of 117±7 nm and showed positive expression of CD63 and CD81 EV markers as measured by ELISA. The presence of key pancreatic transcription factor mRNA, such as NGN3, MAFA and PDX1, and pancreatic hormone proteins such as C-peptide and glucagon, were confirmed in h-Islet-EVs. iPSC clusters were differentiated in suspension and at the end stages of the differentiation protocol, the mRNA expression of the main pancreatic transcription factors and pancreatic hormones was increased. H-Islet-EVs were supplemented to the iPSC clusters in the later stages of differentiation. It was observed that h-Islet-EVs were able to up-regulate the intracellular levels of C-peptide in iPSC clusters in a concentration-dependent manner. The effect of h-Islet-EVs on the differentiation of iPSC clusters cultured in 3D-collagen hydrogels was also assessed. Although increased mRNA expression for pancreatic markers was observed when culturing the iPSC clusters in 3D-collagen hydrogels, delivery of EVs did not affect the insulin or C-peptide intracellular content. Our results provide new information on the role of h-Islet-EVs in the regulation of insulin expression in differentiating iPSC clusters, and are highly relevant for pancreatic tissue engineering applications.

  11. High-fat diet-induced insulin resistance does not increase plasma anandamide levels or potentiate anandamide insulinotropic effect in isolated canine islets.

    Science.gov (United States)

    Woolcott, Orison O; Richey, Joyce M; Kabir, Morvarid; Chow, Robert H; Iyer, Malini S; Kirkman, Erlinda L; Stefanovski, Darko; Lottati, Maya; Kim, Stella P; Harrison, L Nicole; Ionut, Viorica; Zheng, Dan; Hsu, Isabel R; Catalano, Karyn J; Chiu, Jenny D; Bradshaw, Heather; Wu, Qiang; Kolka, Cathryn M; Bergman, Richard N

    2015-01-01

    Obesity has been associated with elevated plasma anandamide levels. In addition, anandamide has been shown to stimulate insulin secretion in vitro, suggesting that anandamide might be linked to hyperinsulinemia. To determine whether high-fat diet-induced insulin resistance increases anandamide levels and potentiates the insulinotropic effect of anandamide in isolated pancreatic islets. Dogs were fed a high-fat diet (n = 9) for 22 weeks. Abdominal fat depot was quantified by MRI. Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Fasting plasma endocannabinoid levels were analyzed by liquid chromatography-mass spectrometry. All metabolic assessments were performed before and after fat diet regimen. At the end of the study, pancreatic islets were isolated prior to euthanasia to test the in vitro effect of anandamide on islet hormones. mRNA expression of cannabinoid receptors was determined in intact islets. The findings in vitro were compared with those from animals fed a control diet (n = 7). Prolonged fat feeding increased abdominal fat content by 81.3±21.6% (mean±S.E.M, Pcanines, high-fat diet-induced insulin resistance does not alter plasma anandamide levels or further potentiate the insulinotropic effect of anandamide in vitro.

  12. Pancreatic islet-like clusters from bone marrow mesenchymal stem cells of human first-trimester abortus can cure streptozocin-induced mouse diabetes.

    Science.gov (United States)

    Zhang, Yihua; Shen, Wenzheng; Hua, Jinlian; Lei, Anmin; Lv, Changrong; Wang, Huayan; Yang, Chunrong; Gao, Zhimin; Dou, Zhongying

    2010-12-01

    Bone marrow mesenchymal stem cells (BMSCs) have been reported to possess low immunogenicity and cause immunosuppression of recipients when allografted. They can differentiate into insulin-producing cells and may be a valuable source for islet formation. However, the extremely low differentiating rate of adult BMSCs toward insulin-producing cells and the insufficient insulin secretion of the differentiated BMSCs in vitro prevent their clinical use in diabetes treatment. Little is known about the potential of cell replacement therapy with human BMSCs. Previously, we isolated and identified human first-trimester fetal BMSCs (hfBMSCs). Under a novel four-step induction procedure established in this study, the hfBMSCs effectively differentiated into functional pancreatic islet-like cell clusters that contained 62 ± 14% insulin-producing cells, expressed a broad gene profile related to pancreatic islet β-cell development, and released high levels of insulin (2.245 ± 0.222 pmol/100 clusters per 30 min) and C-peptide (2.200 ± 0.468 pmol/100 clusters per 30 min) in response to 25 mmol/L glucose stimulus in vitro. The pancreatic islet-like cell clusters normalized the blood glucose level of diabetic model mice for at least 9 weeks when xenografted; blood glucose levels in these mice rose abnormally again when the grafts were removed. Examination of the grafts indicated that the transplanted cells survived in recipients and produced human insulin and C-peptide in situ. These results demonstrate that hfBMSCs derived from a human first-trimester abortus can differentiate into pancreatic islet-like cell clusters following an established four-step induction. The insulin-producing clusters present advantages in cell replacement therapy of type 1 diabetic model mice.

  13. Kill two birds with one stone: making multi-transgenic pre-diabetes mouse models through insulin resistance and pancreatic apoptosis pathogenesis

    Directory of Open Access Journals (Sweden)

    Siyuan Kong

    2018-04-01

    Full Text Available Background Type 2 diabetes is characterized by insulin resistance accompanied by defective insulin secretion. Transgenic mouse models play an important role in medical research. However, single transgenic mouse models may not mimic the complex phenotypes of most cases of type 2 diabetes. Methods Focusing on genes related to pancreatic islet damage, peripheral insulin resistance and related environmental inducing factors, we generated single-transgenic (C/EBP homology protein, CHOP mice (CHOP mice, dual-transgenic (human islet amyloid polypeptide, hIAPP; CHOP mice (hIAPP-CHOP mice and triple-transgenic (11β-hydroxysteroid dehydrogenase type 1, 11β-HSD1; hIAPP; CHOP mice (11β-HSD1-hIAPP- CHOP mice. The latter two types of transgenic (Tg animals were induced with high-fat high-sucrose diets (HFHSD. We analyzed the diabetes-related symptoms and histology features of the transgenic animals. Results Comparing symptoms on the spot-checked points, we determined that the triple-transgene mice were more suitable for systematic study. The results of intraperitoneal glucose tolerance tests (IPGTT of triple-transgene animals began to change 60 days after induction (p < 0.001. After 190 days of induction, the body weights (p < 0.01 and plasma glucose of the animals in Tg were higher than those of the animals in Negative Control (Nc. After sacrificed, large amounts of lipid were found deposited in adipose (p < 0.01 and ectopically deposited in the non-adipose tissues (p < 0.05 or 0.01 of the animals in the Tg HFHSD group. The weights of kidneys and hearts of Tg animals were significantly increased (p < 0.01. Serum C peptide (C-P was decreased due to Tg effects, and insulin levels were increased due to the effects of the HFHSD in the Tg HFHSD group, indicating that damaged insulin secretion and insulin resistance hyperinsulinemia existed simultaneously in these animals. The serum corticosterone of Tg was slightly higher than those of Nc due to the

  14. A review of piscine islet xenotransplantation using wild-type tilapia donors and the production of transgenic tilapia expressing a “humanized” tilapia insulin

    Science.gov (United States)

    Wright, James R; Yang, Hua; Hyrtsenko, Olga; Xu, Bao-You; Yu, Weiming; Pohajdak, Bill

    2014-01-01

    Most islet xenotransplantation laboratories have focused on porcine islets, which are both costly and difficult to isolate. Teleost (bony) fish, such as tilapia, possess macroscopically visible distinct islet organs called Brockmann bodies which can be inexpensively harvested. When transplanted into diabetic nude mice, tilapia islets maintain long-term normoglycemia and provide human-like glucose tolerance profiles. Like porcine islets, when transplanted into euthymic mice, they are rejected in a CD4 T-cell-dependent manner. However, unlike pigs, tilapia are so phylogenetically primitive that their cells do not express α(1,3)Gal and, because tilapia are highly evolved to live in warm stagnant waters nearly devoid of dissolved oxygen, their islet cells are exceedingly resistant to hypoxia, making them ideal for transplantation within encapsulation devices. Encapsulation, especially when combined with co-stimulatory blockade, markedly prolongs tilapia islet xenograft survival in small animal recipients, and a collaborator has shown function in diabetic cynomolgus monkeys. In anticipation of preclinical xenotransplantation studies, we have extensively characterized tilapia islets (morphology, embryologic development, cell biology, peptides, etc.) and their regulation of glucose homeostasis. Because tilapia insulin differs structurally from human insulin by 17 amino acids, we have produced transgenic tilapia whose islets stably express physiological levels of humanized insulin and have now bred these to homozygosity. These transgenic fish can serve as a platform for further development into a cell therapy product for diabetes. PMID:25040337

  15. High-fat diet-induced insulin resistance does not increase plasma anandamide levels or potentiate anandamide insulinotropic effect in isolated canine islets.

    Directory of Open Access Journals (Sweden)

    Orison O Woolcott

    Full Text Available Obesity has been associated with elevated plasma anandamide levels. In addition, anandamide has been shown to stimulate insulin secretion in vitro, suggesting that anandamide might be linked to hyperinsulinemia.To determine whether high-fat diet-induced insulin resistance increases anandamide levels and potentiates the insulinotropic effect of anandamide in isolated pancreatic islets.Dogs were fed a high-fat diet (n = 9 for 22 weeks. Abdominal fat depot was quantified by MRI. Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Fasting plasma endocannabinoid levels were analyzed by liquid chromatography-mass spectrometry. All metabolic assessments were performed before and after fat diet regimen. At the end of the study, pancreatic islets were isolated prior to euthanasia to test the in vitro effect of anandamide on islet hormones. mRNA expression of cannabinoid receptors was determined in intact islets. The findings in vitro were compared with those from animals fed a control diet (n = 7.Prolonged fat feeding increased abdominal fat content by 81.3±21.6% (mean±S.E.M, P<0.01. In vivo insulin sensitivity decreased by 31.3±12.1% (P<0.05, concomitant with a decrease in plasma 2-arachidonoyl glycerol (from 39.1±5.2 to 15.7±2.0 nmol/L but not anandamide, oleoyl ethanolamide, linoleoyl ethanolamide, or palmitoyl ethanolamide. In control-diet animals (body weight: 28.8±1.0 kg, islets incubated with anandamide had a higher basal and glucose-stimulated insulin secretion as compared with no treatment. Islets from fat-fed animals (34.5±1.3 kg; P<0.05 versus control did not exhibit further potentiation of anandamide-induced insulin secretion as compared with control-diet animals. Glucagon but not somatostatin secretion in vitro was also increased in response to anandamide, but there was no difference between groups (P = 0.705. No differences in gene expression of CB1R or CB2R between groups were found.In canines, high-fat diet

  16. Glutathione peroxidase mimic ebselen improves glucose-stimulated insulin secretion in murine islets.

    Science.gov (United States)

    Wang, Xinhui; Yun, Jun-Won; Lei, Xin Gen

    2014-01-10

    Glutathione peroxidase (GPX) mimic ebselen and superoxide dismutase (SOD) mimic copper diisopropylsalicylate (CuDIPs) were used to rescue impaired glucose-stimulated insulin secretion (GSIS) in islets of GPX1 and(or) SOD1-knockout mice. Ebselen improved GSIS in islets of all four tested genotypes. The rescue in the GPX1 knockout resulted from a coordinated transcriptional regulation of four key GSIS regulators and was mediated by the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α)-mediated signaling pathways. In contrast, CuDIPs improved GSIS only in the SOD1 knockout and suppressed gene expression of the PGC-1α pathway. Islets from the GPX1 and(or) SOD1 knockout mice provided metabolically controlled intracellular hydrogen peroxide (H2O2) and superoxide conditions for the present study to avoid confounding effects. Bioinformatics analyses of gene promoters and expression profiles guided the search for upstream signaling pathways to link the ebselen-initiated H2O2 scavenging to downstream key events of GSIS. The RNA interference was applied to prove PGC-1α as the main mediator for that link. Our study revealed a novel metabolic use and clinical potential of ebselen in rescuing GSIS in the GPX1-deficient islets and mice, along with distinct differences between the GPX and SOD mimics in this regard. These findings highlight the necessities and opportunities of discretional applications of various antioxidant enzyme mimics in treating insulin secretion disorders. REBOUND TRACK: This work was rejected during standard peer review and rescued by Rebound Peer Review (Antioxid Redox Signal 16: 293-296, 2012) with the following serving as open reviewers: Regina Brigelius-Flohe, Vadim Gladyshev, Dexing Hou, and Holger Steinbrenner.

  17. A study of the pancreatic islet β-cell function and insulin resistance of type2 diabetic gastroparesis

    International Nuclear Information System (INIS)

    Zou Gang; Shao Hao; Lu Zeyuan; Ding Yuzhen; Chen Guanrong; Fu Juan

    2005-01-01

    Objective: To study the pancreatic islet β-cell function and insulin resistance of diabetic gastroparesis (DGP). Methods: 31 subjects with normal glucose tolerance (NGT), 32 subjects with impaired glucose tolerance (IGT), 38 subjects with type 2 diabetes mellitus (T2DM) and 31 subjects with DGP were en-rolled in the study, assessed by steamed bread meal tests, the plasma glucose and insulin at 0, 30, 60, 120 and 180 min were respectively measured by using glucose oxidase and radioimmunoassay, investigate the changes of area under insulin cure (INSAUC), Homa-insulin resistance (Homa-IR) index and modified β-cell function index (MBCI). Results: The INSAUC of IGT, T2DM, NGT and DGP fell in turn, there were signif-icantly differences among the groups. The Homa-IR index of NGT, IGT, DGP and T2DM rose in turn, there were significantly differences among the groupsexcept between T2DM and DGP. Conclusions: The pancreatic islet β-cell function of DGP was worse that NGT, IGT and T2DM, and the insulin resistance was stronger than NGT and IGT. (authors)

  18. Fibroblasts accelerate islet revascularization and improve long-term graft survival in a mouse model of subcutaneous islet transplantation.

    Directory of Open Access Journals (Sweden)

    Marcos Perez-Basterrechea

    Full Text Available Pancreatic islet transplantation has been considered for many years a promising therapy for beta-cell replacement in patients with type-1 diabetes despite that long-term clinical results are not as satisfactory. This fact points to the necessity of designing strategies to improve and accelerate islets engraftment, paying special attention to events assuring their revascularization. Fibroblasts constitute a cell population that collaborates on tissue homeostasis, keeping the equilibrium between production and degradation of structural components as well as maintaining the required amount of survival factors. Our group has developed a model for subcutaneous islet transplantation using a plasma-based scaffold containing fibroblasts as accessory cells that allowed achieving glycemic control in diabetic mice. Transplanted tissue engraftment is critical during the first days after transplantation, thus we have gone in depth into the graft-supporting role of fibroblasts during the first ten days after islet transplantation. All mice transplanted with islets embedded in the plasma-based scaffold reversed hyperglycemia, although long-term glycemic control was maintained only in the group transplanted with the fibroblasts-containing scaffold. By gene expression analysis and histology examination during the first days we could conclude that these differences might be explained by overexpression of genes involved in vessel development as well as in β-cell regeneration that were detected when fibroblasts were present in the graft. Furthermore, fibroblasts presence correlated with a faster graft re-vascularization, a higher insulin-positive area and a lower cell death. Therefore, this work underlines the importance of fibroblasts as accessory cells in islet transplantation, and suggests its possible use in other graft-supporting strategies.

  19. Fibroblasts accelerate islet revascularization and improve long-term graft survival in a mouse model of subcutaneous islet transplantation.

    Science.gov (United States)

    Perez-Basterrechea, Marcos; Esteban, Manuel Martinez; Alvarez-Viejo, Maria; Fontanil, Tania; Cal, Santiago; Sanchez Pitiot, Marta; Otero, Jesus; Obaya, Alvaro Jesus

    2017-01-01

    Pancreatic islet transplantation has been considered for many years a promising therapy for beta-cell replacement in patients with type-1 diabetes despite that long-term clinical results are not as satisfactory. This fact points to the necessity of designing strategies to improve and accelerate islets engraftment, paying special attention to events assuring their revascularization. Fibroblasts constitute a cell population that collaborates on tissue homeostasis, keeping the equilibrium between production and degradation of structural components as well as maintaining the required amount of survival factors. Our group has developed a model for subcutaneous islet transplantation using a plasma-based scaffold containing fibroblasts as accessory cells that allowed achieving glycemic control in diabetic mice. Transplanted tissue engraftment is critical during the first days after transplantation, thus we have gone in depth into the graft-supporting role of fibroblasts during the first ten days after islet transplantation. All mice transplanted with islets embedded in the plasma-based scaffold reversed hyperglycemia, although long-term glycemic control was maintained only in the group transplanted with the fibroblasts-containing scaffold. By gene expression analysis and histology examination during the first days we could conclude that these differences might be explained by overexpression of genes involved in vessel development as well as in β-cell regeneration that were detected when fibroblasts were present in the graft. Furthermore, fibroblasts presence correlated with a faster graft re-vascularization, a higher insulin-positive area and a lower cell death. Therefore, this work underlines the importance of fibroblasts as accessory cells in islet transplantation, and suggests its possible use in other graft-supporting strategies.

  20. Ex vivo expanded human regulatory T cells delay islet allograft rejection via inhibiting islet-derived monocyte chemoattractant protein-1 production in CD34+ stem cells-reconstituted NOD-scid IL2rγnull mice.

    Science.gov (United States)

    Xiao, Fang; Ma, Liang; Zhao, Min; Huang, Guocai; Mirenda, Vincenzo; Dorling, Anthony; Lechler, Robert; Lombardi, Giovanna

    2014-01-01

    Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by immune-mediated destruction of insulin-secreting β cells of the pancreas. Near complete dependence on exogenous insulin makes T1DM very difficult to control, with the result that patients are exposed to high blood glucose and risk of diabetic complications and/or intermittent low blood glucose that can cause unconsciousness, fits and even death. Allograft transplantation of pancreatic islets restores normoglycemia with a low risk of surgical complications. However, although successful immediately after transplantation, islets are progressively lost, with most of the patients requiring exogenous insulin within 2 years post-transplant. Therefore, there is an urgent requirement for the development of new strategies to prevent islet rejection. In this study, we explored the importance of human regulatory T cells in the control of islets allograft rejection. We developed a pre-clinical model of human islet transplantation by reconstituting NOD-scid IL2rγnull mice with cord blood-derived human CD34+ stem cells and demonstrated that although the engrafted human immune system mediated the rejection of human islets, their survival was significantly prolonged following adoptive transfer of ex vivo expanded human Tregs. Mechanistically, Tregs inhibited the infiltration of innate immune cells and CD4+ T cells into the graft by down-regulating the islet graft-derived monocyte chemoattractant protein-1. Our findings might contribute to the development of clinical strategies for Treg therapy to control human islet rejection. We also show for the first time that CD34+ cells-reconstituted NOD-scid IL2rγnull mouse model could be beneficial for investigating human innate immunity in vivo.

  1. Ex Vivo Expanded Human Regulatory T Cells Delay Islet Allograft Rejection via Inhibiting Islet-Derived Monocyte Chemoattractant Protein-1 Production in CD34+ Stem Cells-Reconstituted NOD-scid IL2rγnull Mice

    Science.gov (United States)

    Xiao, Fang; Ma, Liang; Zhao, Min; Huang, Guocai; Mirenda, Vincenzo; Dorling, Anthony

    2014-01-01

    Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by immune-mediated destruction of insulin-secreting β cells of the pancreas. Near complete dependence on exogenous insulin makes T1DM very difficult to control, with the result that patients are exposed to high blood glucose and risk of diabetic complications and/or intermittent low blood glucose that can cause unconsciousness, fits and even death. Allograft transplantation of pancreatic islets restores normoglycemia with a low risk of surgical complications. However, although successful immediately after transplantation, islets are progressively lost, with most of the patients requiring exogenous insulin within 2 years post-transplant. Therefore, there is an urgent requirement for the development of new strategies to prevent islet rejection. In this study, we explored the importance of human regulatory T cells in the control of islets allograft rejection. We developed a pre-clinical model of human islet transplantation by reconstituting NOD-scid IL2rγnull mice with cord blood-derived human CD34+ stem cells and demonstrated that although the engrafted human immune system mediated the rejection of human islets, their survival was significantly prolonged following adoptive transfer of ex vivo expanded human Tregs. Mechanistically, Tregs inhibited the infiltration of innate immune cells and CD4+ T cells into the graft by down-regulating the islet graft-derived monocyte chemoattractant protein-1. Our findings might contribute to the development of clinical strategies for Treg therapy to control human islet rejection. We also show for the first time that CD34+ cells-reconstituted NOD-scid IL2rγnull mouse model could be beneficial for investigating human innate immunity in vivo. PMID:24594640

  2. Ex vivo expanded human regulatory T cells delay islet allograft rejection via inhibiting islet-derived monocyte chemoattractant protein-1 production in CD34+ stem cells-reconstituted NOD-scid IL2rγnull mice.

    Directory of Open Access Journals (Sweden)

    Fang Xiao

    Full Text Available Type 1 diabetes mellitus (T1DM is an autoimmune disease caused by immune-mediated destruction of insulin-secreting β cells of the pancreas. Near complete dependence on exogenous insulin makes T1DM very difficult to control, with the result that patients are exposed to high blood glucose and risk of diabetic complications and/or intermittent low blood glucose that can cause unconsciousness, fits and even death. Allograft transplantation of pancreatic islets restores normoglycemia with a low risk of surgical complications. However, although successful immediately after transplantation, islets are progressively lost, with most of the patients requiring exogenous insulin within 2 years post-transplant. Therefore, there is an urgent requirement for the development of new strategies to prevent islet rejection. In this study, we explored the importance of human regulatory T cells in the control of islets allograft rejection. We developed a pre-clinical model of human islet transplantation by reconstituting NOD-scid IL2rγnull mice with cord blood-derived human CD34+ stem cells and demonstrated that although the engrafted human immune system mediated the rejection of human islets, their survival was significantly prolonged following adoptive transfer of ex vivo expanded human Tregs. Mechanistically, Tregs inhibited the infiltration of innate immune cells and CD4+ T cells into the graft by down-regulating the islet graft-derived monocyte chemoattractant protein-1. Our findings might contribute to the development of clinical strategies for Treg therapy to control human islet rejection. We also show for the first time that CD34+ cells-reconstituted NOD-scid IL2rγnull mouse model could be beneficial for investigating human innate immunity in vivo.

  3. Pancreatic Islet Cell Transplantation

    Science.gov (United States)

    Warnock, Garth L.; Rajotte, Ray V.

    1992-01-01

    Transplantation of insulin-producing tissue offers a physiologic approach to restoration of glycemic control. Whereas transplantation of vascularized pancreatic grafts has recently achieved encouraging results, pancreatic islet cell transplantation holds the promise of low morbidity and reduced requirements for agressive immunosuppression for recipients. Islet cell transplantation was recently demonstrated to induce euglycemia with insulin independence. Imagesp1656-a PMID:21221366

  4. Islet transplantation using donors after cardiac death: report of the Japan Islet Transplantation Registry.

    Science.gov (United States)

    Saito, Takuro; Gotoh, Mitsukazu; Satomi, Susumu; Uemoto, Shinji; Kenmochi, Takashi; Itoh, Toshinori; Kuroda, Yoshikazu; Yasunami, Youichi; Matsumoto, Shnichi; Teraoka, Satoshi

    2010-10-15

    This report summarizes outcomes of islet transplantation employing donors after cardiac death (DCD) between 2004 and 2007 as reported to the Japan Islet Transplantation Registry. Sixty-five islet isolations were performed for 34 transplantations in 18 patients with insulin-dependent diabetes mellitus, including two patients who had prior kidney transplantation. All but one donor (64/65) was DCD at the time of harvesting. Factors influencing criteria for islet release included duration of low blood pressure of the donor, cold ischemic time, and usage of Kyoto solution for preservation. Multivariate analysis selected usage of Kyoto solution as most important. Of the 18 recipients, 8, 4, and 6 recipients received 1, 2, and 3 islet infusions, respectively. Overall graft survival defined as C-peptide level more than or equal to 0.3 ng/mL was 76.5%, 47.1%, and 33.6% at 1, 2, and 3 years, respectively, whereas corresponding graft survival after multiple transplantations was 100%, 80.0%, and 57.1%, respectively. All recipients remained free of severe hypoglycemia while three achieved insulin independence for 14, 79, and 215 days. HbA1c levels and requirement of exogenous insulin were significantly improved in all patients. Islet transplantation employing DCD can ameliorate severe hypoglycemic episodes, significantly improve HbA1c levels, sustain significant levels of C-peptide, and achieve insulin independence after multiple transplantations. Thus, DCD can be an important resource for islet transplantation if used under strict releasing criteria and in multiple transplantations, particularly in countries where heart-beating donors are not readily available.

  5. Beneficial effect of D-allose for isolated islet culture prior to islet transplantation.

    Science.gov (United States)

    Kashiwagi, Hirotaka; Asano, Eisuke; Noguchi, Chisato; Sui, Li; Hossain, Akram; Akamoto, Shintaro; Okano, Keiichi; Tokuda, Masaaki; Suzuki, Yasuyuki

    2016-01-01

    Pretransplant restoration of islets damaged during isolation remains to be solved. In this study, we examined the effect of D-allose on islets isolated from rat pancreata prior to islet transplantation. Rat islets isolated from fresh pancreata were cultured overnight in Roswell Park Memorial Institute 1640 solution in the absence (group 1) or presence (group 2) of D-allose. Then we assessed stimulation index of insulin, and cure rate after islet transplantation to diabetic nude mice. We also measured malondialdehyde level and caspase 3 activity of islets after the overnight culture for assessment of the oxidative stress and the apoptosis. D-allose significantly improved insulin secretion of islets. The stimulation index in group 2 was significantly higher than in group 1. Cure rate after transplantation in group 2 was higher than in group 1 especially in the first week. The malondialdehyde level in group 2 was significantly lower than in group 1. But the caspase 3 activities in both groups did not differ. D-allose treatment of isolated islet culture prior to transplantation restored islet function and increased successful transplant rate. The results of this study suggested that D-allose improved function of damaged islets through its anti-oxidative activity. © 2015 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

  6. Deletion of GPR40 Impairs Glucose-Induced Insulin Secretion In Vivo in Mice Without Affecting Intracellular Fuel Metabolism in Islets

    Energy Technology Data Exchange (ETDEWEB)

    Alquier, Thierry; Peyot, Marie-Line; Latour, M. G.; Kebede, Melkam; Sorensen, Christina M.; Gesta, Stephane; Kahn, C. R.; Smith, Richard D.; Jetton, Thomas L.; Metz, Thomas O.; Prentki, Marc; Poitout, Vincent J.

    2009-11-01

    The G protein-coupled receptor GPR40 mediates fatty-acid potentiation of glucose-stimulated insulin secretion, but its contribution to insulin secretion in vivo and mechanisms of action remain uncertain. This study was aimed to ascertain whether GPR40 controls insulin secretion in vivo and modulates intracellular fuel metabolism in islets. We observed that glucose- and arginine-stimulated insulin secretion, assessed by hyperglycemic clamps, was decreased by approximately 60% in GPR40 knock-out (KO) fasted and fed mice, without changes in insulin sensitivity assessed by hyperinsulinemic-euglycemic clamps. Glucose and palmitate metabolism were not affected by GPR40 deletion. Lipid profiling revealed a similar increase in triglyceride and decrease in lysophosphatidylethanolamine species in WT and KO islets in response to palmitate. These results demonstrate that GPR40 regulates insulin secretion in vivo not only in response to fatty acids but also to glucose and arginine, without altering intracellular fuel metabolism.

  7. HLA-B*39:06 Efficiently Mediates Type 1 Diabetes in a Mouse Model Incorporating Reduced Thymic Insulin Expression.

    Science.gov (United States)

    Schloss, Jennifer; Ali, Riyasat; Racine, Jeremy J; Chapman, Harold D; Serreze, David V; DiLorenzo, Teresa P

    2018-04-09

    Type 1 diabetes (T1D) is characterized by T cell-mediated destruction of the insulin-producing β cells of the pancreatic islets. Among the loci associated with T1D risk, those most predisposing are found in the MHC region. HLA-B*39:06 is the most predisposing class I MHC allele and is associated with an early age of onset. To establish an NOD mouse model for the study of HLA-B*39:06, we expressed it in the absence of murine class I MHC. HLA-B*39:06 was able to mediate the development of CD8 T cells, support lymphocytic infiltration of the islets, and confer T1D susceptibility. Because reduced thymic insulin expression is associated with impaired immunological tolerance to insulin and increased T1D risk in patients, we incorporated this in our model as well, finding that HLA-B*39:06-transgenic NOD mice with reduced thymic insulin expression have an earlier age of disease onset and a higher overall prevalence as compared with littermates with typical thymic insulin expression. This was despite virtually indistinguishable blood insulin levels, T cell subset percentages, and TCR Vβ family usage, confirming that reduced thymic insulin expression does not impact T cell development on a global scale. Rather, it will facilitate the thymic escape of insulin-reactive HLA-B*39:06-restricted T cells, which participate in β cell destruction. We also found that in mice expressing either HLA-B*39:06 or HLA-A*02:01 in the absence of murine class I MHC, HLA transgene identity alters TCR Vβ usage by CD8 T cells, demonstrating that some TCR Vβ families have a preference for particular class I MHC alleles. Copyright © 2018 by The American Association of Immunologists, Inc.

  8. Bioluminescence imaging of β cells and intrahepatic insulin gene activity under normal and pathological conditions.

    Directory of Open Access Journals (Sweden)

    Tokio Katsumata

    Full Text Available In diabetes research, bioluminescence imaging (BLI has been applied in studies of β-cell impairment, development, and islet transplantation. To develop a mouse model that enables noninvasive imaging of β cells, we generated a bacterial artificial chromosome (BAC transgenic mouse in which a mouse 200-kbp genomic fragment comprising the insulin I gene drives luciferase expression (Ins1-luc BAC transgenic mouse. BLI of mice was performed using the IVIS Spectrum system after intraperitoneal injection of luciferin, and the bioluminescence signal from the pancreatic region analyzed. When compared with MIP-Luc-VU mice [FVB/N-Tg(Ins1-lucVUPwrs/J] expressing luciferase under the control of the 9.2-kbp mouse insulin I promoter (MIP, the bioluminescence emission from Ins1-luc BAC transgenic mice was enhanced approximately 4-fold. Streptozotocin-treated Ins1-luc BAC transgenic mice developed severe diabetes concomitant with a sharp decline in the BLI signal intensity in the pancreas. Conversely, mice fed a high-fat diet for 8 weeks showed an increase in the signal, reflecting a decrease or increase in the β-cell mass. Although the bioluminescence intensity of the islets correlated well with the number of isolated islets in vitro, the intensity obtained from a living mouse in vivo did not necessarily reflect an absolute quantification of the β-cell mass under pathological conditions. On the other hand, adenovirus-mediated gene transduction of β-cell-related transcription factors in Ins1-luc BAC transgenic mice generated luminescence from the hepatic region for more than 1 week. These results demonstrate that BLI in Ins1-luc BAC transgenic mice provides a noninvasive method of imaging islet β cells and extrapancreatic activity of the insulin gene in the liver under normal and pathological conditions.

  9. Affinity-purified human interleukin I is cytotoxic to isolated islets of Langerhans

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Bendtzen, K; Nerup, J

    1986-01-01

    Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets. These e......Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets...

  10. A novel subcutaneous site of islet transplantation superior to the liver.

    Science.gov (United States)

    Yasunami, Yohichi; Nakafusa, Yuki; Nitta, Naoyoshi; Nakamura, Masafumi; Goto, Masafumi; Ono, Junko; Taniguchi, Masaru

    2018-03-08

    Islet transplantation is an attractive treatment for patients with insulin-dependent diabetes mellitus, and currently the liver is the favored transplantation site. However, an alternative site is desirable because of the low efficiency of hepatic transplantation, requiring 2-3 donors for a single recipient, and because the transplanted islets cannot be accessed or retrieved. We developed a novel procedure of islet transplantation to the inguinal subcutaneous white adipose tissue (ISWAT) of mice and described functional and morphological characteristics of transplanted syngeneic islets. Also, it was determined whether islet allograft rejection in the ISWAT can be prevented by immunosuppressive agents. Furthermore, it was examined whether human islets function when grafted in this particular site of immune-deficient mice. In this site, transplanted islets are engrafted as clusters and function to reverse STZ-induced diabetes in mice. Importantly, transplanted islets can be visualized by CT and are easily retrievable, and allograft rejection is preventable by blockade of co-stimulatory signals. Of much importance, the efficiency of islet transplantation in this site is superior to the liver, in which hyperglycemia of diabetic recipient mice is ameliorated after transplantation of 200 syngeneic islets (the islet number yielded from 1 mouse pancreas) to the ISWAT but not to the liver. Furthermore, human islets transplanted in this particular site function to reverse diabetes in immune-deficient mice. Thus, the ISWAT is superior to the liver as the site of islet transplantation, which may lead to improved outcome of clinical islet transplantation.

  11. Redox-Dependent Inflammation in Islet Transplantation Rejection

    Directory of Open Access Journals (Sweden)

    Jessie M. Barra

    2018-04-01

    Full Text Available Type 1 diabetes is an autoimmune disease that results in the progressive destruction of insulin-producing pancreatic β-cells inside the islets of Langerhans. The loss of this vital population leaves patients with a lifelong dependency on exogenous insulin and puts them at risk for life-threatening complications. One method being investigated to help restore insulin independence in these patients is islet cell transplantation. However, challenges associated with transplant rejection and islet viability have prevented long-term β-cell function. Redox signaling and the production of reactive oxygen species (ROS by recipient immune cells and transplanted islets themselves are key players in graft rejection. Therefore, dissipation of ROS generation is a viable intervention that can protect transplanted islets from immune-mediated destruction. Here, we will discuss the newly appreciated role of redox signaling and ROS synthesis during graft rejection as well as new strategies being tested for their efficacy in redox modulation during islet cell transplantation.

  12. Redox-Dependent Inflammation in Islet Transplantation Rejection

    Science.gov (United States)

    Barra, Jessie M.; Tse, Hubert M.

    2018-01-01

    Type 1 diabetes is an autoimmune disease that results in the progressive destruction of insulin-producing pancreatic β-cells inside the islets of Langerhans. The loss of this vital population leaves patients with a lifelong dependency on exogenous insulin and puts them at risk for life-threatening complications. One method being investigated to help restore insulin independence in these patients is islet cell transplantation. However, challenges associated with transplant rejection and islet viability have prevented long-term β-cell function. Redox signaling and the production of reactive oxygen species (ROS) by recipient immune cells and transplanted islets themselves are key players in graft rejection. Therefore, dissipation of ROS generation is a viable intervention that can protect transplanted islets from immune-mediated destruction. Here, we will discuss the newly appreciated role of redox signaling and ROS synthesis during graft rejection as well as new strategies being tested for their efficacy in redox modulation during islet cell transplantation. PMID:29740396

  13. Attenuation of primary nonfunction for syngeneic islet graft using sodium 4-phenylbutyrate.

    Science.gov (United States)

    Fu, S-H; Chen, S-T; Hsu, B R-S

    2005-05-01

    Sodium 4-phenylbutyrate (4-SPB), an aromatic derivative of butyric acid, was examined to elucidate its effect on islet engraftment in a syngeneic transplantation model using C57BL/6 mice. Diabetic mice that received subrenal implantation of 150 islets on day 0 and oral administration of twice daily 4-SPB (500 mg/kg body weight) on days -2 through 28 displayed a significantly shorter duration of posttransplantation temporary hyperglycemia than diabetic mice that received islets in isotonic sodium chloride solution (NaCl), namely 16 +/- 2 (n = 12) vs 23 +/- 2 days (n = 7; P < .05). Four weeks after transplantation, the insulin content (IC) of grafts from mice treated with islets and 4-SPB was substantially higher than that of grafts from mice treated with islets and NaCl, namely 2.59 +/- 0.37 (n = 8) vs 1.36 +/- 0.36 mug (n = 13; P < .01). The IC of pancreatic remnants showed no significant difference between groups after 2 and 4 weeks of incubation. In vitro studies demonstrated that the net glucose-stimulated insulin secretion (GSIS) and the ratio of net GSIS to the IC of islets cultured with 4-SPB (1 mM) did not differ significantly from those cultured with NaCl. The lipopolysaccharide-stimulated secretions of IL-1beta, IL-10, and IFNgamma from peritoneal exudate monocytes were significantly reduced by co-incubation with 4-SPB (1 mM). In conclusion, our data suggest that daily administration of 4-SPB reduces primary nonfunction and enhances islet engraftment in a syngeneic mouse transplantation model.

  14. Paracrine GABA and insulin regulate pancreatic alpha cell proliferation in a mouse model of type 1 diabetes.

    Science.gov (United States)

    Feng, Allen L; Xiang, Yun-Yan; Gui, Le; Kaltsidis, Gesthika; Feng, Qingping; Lu, Wei-Yang

    2017-06-01

    This study aimed to elucidate the mechanism of increased proliferation of alpha cells in recent-onset type 1 diabetes. Pancreatic beta cells express GAD and produce γ-aminobutyric acid (GABA), which inhibits alpha cell secretion of glucagon. We explored the roles of GABA in alpha cell proliferation in conditions corresponding to type 1 diabetes in a mouse model and in vitro. Type 1 diabetes was induced by injecting the mice with streptozotocin (STZ). Some of the STZ-injected mice were treated with GABA (10 mg/kg daily) for 12 days. Isolated pancreatic islets were treated with STZ or STZ together with GABA for 2 days. The effects of GABA treatment on STZ-induced alpha cell proliferation in vivo and in vitro were assessed. The effect of muscimol, a GABA receptor agonist, on αTC1-6 cell proliferation was also examined. STZ injection substantially decreased levels of GAD, GABA and insulin in pancreatic beta cells 12 h after injection; this was followed by an upsurge of phosphorylated mechanistic target of rapamycin (p-mTOR) in the alpha cells at day 1, and a significant increase in alpha cell mass at day 3. Treating STZ-injected mice with GABA largely restored the immunodetectable levels of insulin and GAD in the beta cells and significantly decreased the number of aldehyde dehydrogenase 1 family, member A3 (ALDH1a3)-positive cells, alpha cell mass and hyperglucagonaemia. STZ treatment also increased alpha cell proliferation in isolated islets, which was reversed by co-treatment with GABA. Muscimol, together with insulin, significantly lowered the level of cytosolic Ca 2+ and p-mTOR, and decreased the proliferation rate of αTC1-6 cells. GABA signalling critically controls the alpha cell population in pancreatic islets. Low intraislet GABA may contribute to alpha cell hyperplasia in early type 1 diabetes.

  15. Human pancreatic islet transplantation: an update and description of the establishment of a pancreatic islet isolation laboratory.

    Science.gov (United States)

    Rheinheimer, Jakeline; Bauer, Andrea C; Silveiro, Sandra P; Estivalet, Aline A F; Bouças, Ana P; Rosa, Annelise R; Souza, Bianca M de; Oliveira, Fernanda S de; Cruz, Lavínia A; Brondani, Letícia A; Azevedo, Mirela J; Lemos, Natália E; Carlessi, Rodrigo; Assmann, Taís S; Gross, Jorge L; Leitão, Cristiane B; Crispim, Daisy

    2015-04-01

    Type 1 diabetes mellitus (T1DM) is associated with chronic complications that lead to high morbidity and mortality rates in young adults of productive age. Intensive insulin therapy has been able to reduce the likelihood of the development of chronic diabetes complications. However, this treatment is still associated with an increased incidence of hypoglycemia. In patients with "brittle T1DM", who have severe hypoglycemia without adrenergic symptoms (hypoglycemia unawareness), islet transplantation may be a therapeutic option to restore both insulin secretion and hypoglycemic perception. The Edmonton group demonstrated that most patients who received islet infusions from more than one donor and were treated with steroid-free immunosuppressive drugs displayed a considerable decline in the initial insulin independence rates at eight years following the transplantation, but showed permanent C-peptide secretion, which facilitated glycemic control and protected patients against hypoglycemic episodes. Recently, data published by the Collaborative Islet Transplant Registry (CITR) has revealed that approximately 50% of the patients who undergo islet transplantation are insulin independent after a 3-year follow-up. Therefore, islet transplantation is able to successfully decrease plasma glucose and HbA1c levels, the occurrence of severe hypoglycemia, and improve patient quality of life. The goal of this paper was to review the human islet isolation and transplantation processes, and to describe the establishment of a human islet isolation laboratory at the Endocrine Division of the Hospital de Clínicas de Porto Alegre - Rio Grande do Sul, Brazil.

  16. Nicotinamide induces differentiation of embryonic stem cells into insulin-secreting cells

    International Nuclear Information System (INIS)

    Vaca, Pilar; Berna, Genoveva; Araujo, Raquel; Carneiro, Everardo M.; Bedoya, Francisco J.; Soria, Bernat; Martin, Franz

    2008-01-01

    The poly(ADP-ribose) polymerase (PARP) inhibitor, nicotinamide, induces differentiation and maturation of fetal pancreatic cells. In addition, we have previously reported evidence that nicotinamide increases the insulin content of cells differentiated from embryonic stem (ES) cells, but the possibility of nicotinamide acting as a differentiating agent on its own has never been completely explored. Islet cell differentiation was studied by: (i) X-gal staining after neomycin selection; (ii) BrdU studies; (iii) single and double immunohistochemistry for insulin, C-peptide and Glut-2; (iv) insulin and C-peptide content and secretion assays; and (v) transplantation of differentiated cells, under the kidney capsule, into streptozotocin (STZ)-diabetic mice. Here we show that undifferentiated mouse ES cells treated with nicotinamide: (i) showed an 80% decrease in cell proliferation; (ii) co-expressed insulin, C-peptide and Glut-2; (iii) had values of insulin and C-peptide corresponding to 10% of normal mouse islets; (iv) released insulin and C-peptide in response to stimulatory glucose concentrations; and (v) after transplantation into diabetic mice, normalized blood glucose levels over 7 weeks. Our data indicate that nicotinamide decreases ES cell proliferation and induces differentiation into insulin-secreting cells. Both aspects are very important when thinking about cell therapy for the treatment of diabetes based on ES cells

  17. Metformin Ameliorates Dysfunctional Traits of Glibenclamide- and Glucose-Induced Insulin Secretion by Suppression of Imposed Overactivity of the Islet Nitric Oxide Synthase-NO System.

    Directory of Open Access Journals (Sweden)

    Ingmar Lundquist

    Full Text Available Metformin lowers diabetic blood glucose primarily by reducing hepatic gluconeogenesis and increasing peripheral glucose uptake. However, possible effects by metformin on beta-cell function are incompletely understood. We speculated that metformin might positively influence insulin secretion through impacting the beta-cell nitric oxide synthase (NOS-NO system, a negative modulator of glucose-stimulated insulin release. In short-time incubations with isolated murine islets either glibenclamide or high glucose augmented insulin release associated with increased NO production from both neural and inducible NOS. Metformin addition suppressed the augmented NO generation coinciding with amplified insulin release. Islet culturing with glibenclamide or high glucose revealed pronounced fluorescence of inducible NOS in the beta-cells being abolished by metformin co-culturing. These findings were reflected in medium nitrite-nitrate levels. A glucose challenge following islet culturing with glibenclamide or high glucose revealed markedly impaired insulin response. Metformin co-culturing restored this response. Culturing murine islets and human islets from controls and type 2 diabetics with high glucose or high glucose + glibenclamide induced a pronounced decrease of cell viability being remarkably restored by metformin co-culturing. We show here, that imposed overactivity of the beta-cell NOS-NO system by glibenclamide or high glucose leads to insulin secretory dysfunction and reduced cell viability and also, importantly, that these effects are relieved by metformin inhibiting beta-cell NO overproduction from both neural and inducible NOS thus ameliorating a concealed negative influence by NO induced by sulfonylurea treatment and/or high glucose levels. This double-edged effect of glibenclamide on the beta-cellsuggests sulfonylurea monotherapy in type 2 diabetes being avoided.

  18. A New Method for Generating Insulin-Secreting Cells from Human Pancreatic Epithelial Cells After Islet Isolation Transformed by NeuroD1

    Science.gov (United States)

    Shimoda, Masayuki; Chen, Shuyuan; Noguchi, Hirofumi; Takita, Morihito; Sugimoto, Koji; Itoh, Takeshi; Chujo, Daisuke; Iwahashi, Shuichi; Naziruddin, Bashoo; Levy, Marlon F.

    2014-01-01

    Abstract The generation of insulin-secreting cells from nonendocrine pancreatic epithelial cells (NEPEC) has been demonstrated for potential clinical use in the treatment of diabetes. However, previous methods either had limited efficacy or required viral vectors, which hinder clinical application. In this study, we aimed to establish an efficient method of insulin-secreting cell generation from NEPEC without viral vectors. We used nonislet fractions from both research-grade human pancreata from brain-dead donors and clinical pancreata after total pancreatectomy with autologous islet transplantation to treat chronic pancreatitis. It is of note that a few islets could be mingled in the nonislet fractions, but their influence could be limited. The NeuroD1 gene was induced into NEPEC using an effective triple lipofection method without viral vectors to generate insulin-secreting cells. The differentiation was promoted by adding a growth factor cocktail into the culture medium. Using the research-grade human pancreata, the effective method showed high efficacy in the differentiation of NEPEC into insulin-positive cells that secreted insulin in response to a glucose challenge and improved diabetes after being transplanted into diabetic athymic mice. Using the clinical pancreata, similar efficacy was obtained, even though those pancreata suffered chronic pancreatitis. In conclusion, our effective differentiation protocol with triple lipofection method enabled us to achieve very efficient insulin-secreting cell generation from human NEPEC without viral vectors. This method offers the potential for supplemental insulin-secreting cell transplantation for both allogeneic and autologous islet transplantation. PMID:24845703

  19. Amyloid Deposition in Transplanted Human Pancreatic Islets: A Conceivable Cause of Their Long-Term Failure

    Directory of Open Access Journals (Sweden)

    Arne Andersson

    2008-01-01

    Full Text Available Following the encouraging report of the Edmonton group, there was a rejuvenation of the islet transplantation field. After that, more pessimistic views spread when long-term results of the clinical outcome were published. A progressive loss of the β-cell function meant that almost all patients were back on insulin therapy after 5 years. More than 10 years ago, we demonstrated that amyloid deposits rapidly formed in human islets and in mouse islets transgenic for human IAPP when grafted into nude mice. It is, therefore, conceivable to consider amyloid formation as one potential candidate for the long-term failure. The present paper reviews attempts in our laboratories to elucidate the dynamics of and mechanisms behind the formation of amyloid in transplanted islets with special emphasis on the impact of long-term hyperglycemia.

  20. The journey of islet cell transplantation and future development.

    Science.gov (United States)

    Gamble, Anissa; Pepper, Andrew R; Bruni, Antonio; Shapiro, A M James

    2018-03-04

    Intraportal islet transplantation has proven to be efficacious in preventing severe hypoglycemia and restoring insulin independence in selected patients with type 1 diabetes. Multiple islet infusions are often required to achieve and maintain insulin independence. Many challenges remain in clinical islet transplantation, including substantial islet cell loss early and late after islet infusion. Contributions to graft loss include the instant blood-mediated inflammatory reaction, potent host auto- and alloimmune responses, and beta cell toxicity from immunosuppressive agents. Protective strategies are being tested to circumvent several of these events including exploration of alternative transplantation sites, stem cell-derived insulin producing cell therapies, co-transplantation with mesenchymal stem cells or exploration of novel immune protective agents. Herein, we provide a brief introduction and history of islet cell transplantation, limitations associated with this procedure and methods to alleviate islet cell loss as a means to improve engraftment outcomes.

  1. Type 1 diabetes : The autoimmune process and islet transplantation

    OpenAIRE

    Jacobson, Stella

    2010-01-01

    Type 1 diabetes (T1D) is an autoimmune disease characterized by the selective loss of the insulin-producing β-cells residing in the islets of Langerhans in the pancreas. Cytokines are involved in diabetes development in the nonobese diabetic (NOD) mouse model. NOD mice over-expressing the suppressor of cytokine signaling (SOCS-1) specifically in the β-cells are protected from T1D. Previous studies showed that immune cells infiltrated the pancreas of SOCS-1-transgenic (tg)...

  2. Early and rapid development of insulin resistance, islet dysfunction and glucose intolerance after high-fat feeding in mice overexpressing phosphodiesterase 3B

    DEFF Research Database (Denmark)

    Walz, Helena A; Härndahl, Linda; Wierup, Nils

    2006-01-01

    Inadequate islet adaptation to insulin resistance leads to glucose intolerance and type 2 diabetes. Here we investigate whether beta-cell cAMP is crucial for islet adaptation and prevention of glucose intolerance in mice. Mice with a beta-cell-specific, 2-fold overexpression of the c......AMP-degrading enzyme phosphodiesterase 3B (RIP-PDE3B/2 mice) were metabolically challenged with a high-fat diet. We found that RIP-PDE3B/2 mice early and rapidly develop glucose intolerance and insulin resistance, as compared with wild-type littermates, after 2 months of high-fat feeding. This was evident from...... did not reveal reduced insulin sensitivity in these tissues. Significant steatosis was noted in livers from high-fat-fed wild-type and RIP-PDE3B/2 mice and liver triacyl-glycerol content was 3-fold higher than in wild-type mice fed a control diet. Histochemical analysis revealed severe islet...

  3. Transplantation of co-aggregates of Sertoli cells and islet cells into liver without immunosuppression.

    Science.gov (United States)

    Takemoto, Naohiro; Liu, Xibao; Takii, Kento; Teramura, Yuji; Iwata, Hiroo

    2014-02-15

    Transplantation of islets of Langerhans (islets) was used to treat insulin-dependent diabetes mellitus. However, islet grafts must be maintained by administration of immunosuppressive drugs, which can lead to complications in the long term. An approach that avoids immunosuppressive drug use is desirable. Co-aggregates of Sertoli cells and islet cells from BALB/c mice that were prepared by the hanging drop method were transplanted into C57BL/6 mouse liver through the portal vein as in human clinical islet transplantation. The core part of the aggregates contained mainly Sertoli cells, and these cells were surrounded by islet cells. The co-aggregates retained the functions of both Sertoli and islet cells. When 800 co-aggregates were transplanted into seven C57BL/6 mice via the portal vein, six of seven recipient mice demonstrated quasi-normoglycemia for more than 100 days. The hanging drop method is suitable for preparing aggregates of Sertoli and islet cells for transplantation. Notably, transplantation of these allogeneic co-aggregates into mice with chemically induced diabetes via the portal vein resulted in long-term graft survival without systemic immunosuppression.

  4. Proghrelin-derived peptides influence the secretion of insulin, glucagon, pancreatic polypeptide and somatostatin: a study on isolated islets from mouse and rat pancreas

    DEFF Research Database (Denmark)

    Qader, S.S.; Hakanson, R.; Lundquist, I.

    2008-01-01

    ghrelin, and to the 23-amino acid peptide obestatin, claimed to be a physiological opponent of acyl ghrelin. This study examines the effects of the proghrelin products, alone and in combinations, on the secretion of insulin, glucagon, pancreatic polypeptide (PP) and somatostatin from isolated islets...... times higher concentration than acyl ghrelin (corresponding to the ratio of the two peptides in circulation), desacyl ghrelin abolished the effects of acyl ghrelin but not those of obestatin. Acyl ghrelin and obestatin affected the secretion of glucagon, PP and somatostatin at physiologically relevant...

  5. Immature transformed rat islet beta-cells differentially express C-peptides derived from the genes coding for insulin I and II as well as a transfected human insulin gene

    DEFF Research Database (Denmark)

    Blume, N; Petersen, J S; Andersen, L C

    1992-01-01

    is induced in the transformed heterogeneous rat islet cell clone, NHI-6F, by transient in vivo passage. During this process a transfected human insulin gene is coactivated with the endogenous nonallelic rat insulin I and II genes. Newly established cultures from NHI-6F insulinomas having a high frequency...

  6. Autologous islet transplantation with remote islet isolation after pancreas resection for chronic pancreatitis.

    Science.gov (United States)

    Tai, Denise S; Shen, Na; Szot, Gregory L; Posselt, Andrew; Feduska, Nicholas J; Habashy, Andrew; Clerkin, Barbara; Core, Erin; Busuttil, Ronald W; Hines, O Joe; Reber, Howard A; Lipshutz, Gerald S

    2015-02-01

    Autologous islet transplantation is an elegant and effective method for preserving euglycemia in patients undergoing near-total or total pancreatectomy for severe chronic pancreatitis. However, few centers worldwide perform this complex procedure, which requires interdisciplinary coordination and access to a sophisticated Food and Drug Administration-licensed islet-isolating facility. To investigate outcomes from a single institutional case series of near-total or total pancreatectomy and autologous islet transplantation using remote islet isolation. Retrospective cohort study between March 1, 2007, and December 31, 2013, at tertiary academic referral centers among 9 patients (age range, 13-47 years) with chronic pancreatitis and reduced quality of life after failed medical management. Pancreas resection, followed by transport to a remote facility for islet isolation using a modified Ricordi technique, with immediate transplantation via portal vein infusion. Islet yield, pain assessment, insulin requirement, costs, and transport time. Eight of nine patients had successful islet isolation after near-total or total pancreatectomy. Four of six patients with total pancreatectomy had islet yields exceeding 5000 islet equivalents per kilogram of body weight. At 2 months after surgery, all 9 patients had significantly reduced pain or were pain free. Of these patients, 2 did not require insulin, and 1 required low doses. The mean transport cost was $16,527, and the mean transport time was 3½ hours. Pancreatic resection with autologous islet transplantation for severe chronic pancreatitis is a safe and effective final alternative to ameliorate debilitating pain and to help prevent the development of surgical diabetes. Because many centers lack access to an islet-isolating facility, we describe our experience using a regional 2-center collaboration as a successful model to remotely isolate cells, with outcomes similar to those of larger case series.

  7. Reciprocal links between metabolic and ionic events in islet cells. Their relevance to the rhythmics of insulin release.

    Science.gov (United States)

    Malaisse, W J

    1998-02-01

    The notion of reciprocal links between metabolic and ionic events in islet cells and the rhythmics of insulin release is based on (i) the rhythmic pattern of hormonal release from isolated perfused rat pancreas, which supports the concept of an intrapancreatic pacemaker; (ii) the assumption that this phasic pattern is due to the integration of secretory activity in distinct functional units, e.g. distinct islets; and (iii) the fact that reciprocal coupling between metabolic and ionic events is operative in the secretory sequence.

  8. Insulin release by glucagon and secretin

    DEFF Research Database (Denmark)

    Kofod, Hans; Andreu, D; Thams, P

    1988-01-01

    Secretin and glucagon potentiate glucose-induced insulin release. We have compared the effects of secretin and glucagon with that of four hybrid molecules of the two hormones on insulin release and formation of cyclic AMP (cAMP) in isolated mouse pancreatic islets. All six peptides potentiated...... the release of insulin at 10 mM D-glucose, and their effects were indistinguishable with respect to the dynamics of release, dose-response relationship, and glucose dependency. However, measurements of cAMP accumulation in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (10(-4) M...... potentiating effects of secretin and glucagon on glucose-induced insulin release, their modes of action may be different....

  9. Insulin receptor internalization defect in an insulin-resistant mouse melanoma cell line

    International Nuclear Information System (INIS)

    Androlewicz, M.J.; Straus, D.S.; Brandenburg, D.F.

    1989-01-01

    Previous studies from this laboratory demonstrated that the PG19 mouse melanoma cell line does not exhibit a biological response to insulin, whereas melanoma x mouse embryo fibroblast hybrids do respond to insulin. To investigate the molecular basis of the insulin resistance of the PG19 melanoma cells, insulin receptors from the insulin-resistant melanoma cells and insulin-sensitive fibroblast x melanoma hybrid cells were analyzed by the technique of photoaffinity labeling using the photoprobe 125 I-NAPA-DP-insulin. Photolabeled insulin receptors from the two cell types have identical molecular weights as determined by SDS gel electrophoresis under reducing and nonreducing conditions, indicating that the receptors on the two cell lines are structurally similar. Insulin receptor internalization studies revealed that the hybrid cells internalize receptors to a high degree at 37 degree C, whereas the melanoma cells internalize receptors to a very low degree or not at all. The correlation between ability to internalize insulin receptors and sensitivity to insulin action in this system suggests that uptake of the insulin-receptor complex may be required for insulin action in these cells. Insulin receptors from the two cell lines autophosphorylate in a similar insulin-dependent manner both in vitro and in intact cells, indicating that insulin receptors on the melanoma and hybrid cells have functional tyrosine protein kinase activity. Therefore, the block in insulin action in the PG19 melanoma cells appears to reside at a step beyond insulin-stimulated receptor autophosphorylation

  10. Increased secretion of insulin and proliferation of islet β-cells in rats with mesenteric lymph duct ligation

    International Nuclear Information System (INIS)

    Nagino, Ko; Yokozawa, Junji; Sasaki, Yu; Matsuda, Akiko; Takeda, Hiroaki; Kawata, Sumio

    2012-01-01

    Highlights: ► Insulin secretion was increased during the OGTT or IVGTT in mesenteric lymph duct-ligated rats. ► Proliferation of islet β-cells was upregulated in lymph duct-ligated rats. ► Mesenteric lymph duct flow has a role in glucose metabolism. -- Abstract: Background and aims: It has been suggested that intestinal lymph flow plays an important role in insulin secretion and glucose metabolism after meals. In this study, we investigated the influence of ligation of the mesenteric lymph duct on glucose metabolism and islet β-cells in rats. Methods: Male Sprague–Dawley rats (10 weeks old) were divided into two groups: one underwent ligation of the mesenteric lymph duct above the cistern (ligation group), and the other underwent a sham operation (sham group). After 1 and 2 weeks, fasting plasma concentrations of glucose, insulin, triglyceride, glucose-dependent insulinotropic polypeptide (GIP), and the active form of glucagon-like peptide-1 (GLP-1) were measured. At 2 weeks after the operation, the oral glucose tolerance test (OGTT) and intravenous glucose tolerance test (IVGTT) were performed. After the rats had been sacrificed, the insulin content of the pancreas was measured and the proliferation of β-cells was assessed immunohistochemically using antibodies against insulin and Ki-67. Results: During the OGTT, the ligation group showed a significant decrease in the plasma glucose concentration at 120 min (p < 0.05) and a significant increase in the plasma insulin concentration by more than 2-fold at 15 min (p < 0.01). On the other hand, the plasma GIP concentration was significantly decreased at 60 min (p < 0.01) in the ligated group, while the active form of GLP-1 showed a significantly higher level at 90 min (1.7-fold; p < 0.05) and 120 min (2.5-fold; p < 0.01). During the IVGTT, the plasma insulin concentration in the ligation group was significantly higher at 2 min (more than 1.4-fold; p < 0.05). Immunohistochemistry showed that the ratios of

  11. Construction of EMSC-islet co-localizing composites for xenogeneic porcine islet transplantation.

    Science.gov (United States)

    Kim, Jung-Sik; Chung, Hyunwoo; Byun, Nari; Kang, Seong-Jun; Lee, Sunho; Shin, Jun-Seop; Park, Chung-Gyu

    2018-03-04

    Pancreatic islet transplantation is an ultimate solution for treating patients with type 1 diabetes (T1D). The pig is an ideal donor of islets for replacing scarce human islets. Besides immunological hurdles, non-immunological hurdles including fragmentation and delayed engraftment of porcine islets need solutions to succeed in porcine islet xenotransplantation. In this study, we suggest a simple but effective modality, a cell/islet co-localizing composite, to overcome these challenges. Endothelial-like mesenchymal stem cells (EMSCs), differentiated from bone-marrow derived mouse mesenchymal stem cells (MSCs), and MSCs evenly coated the surface of porcine islets (>85%) through optimized culture conditions. Both MSCs and EMSCs significantly reduced the fragmentation of porcine islets and increased the islet masses, designated as islet equivalents (IEQs). In fibrin in vitro and in vivo angiogenesis analysis, constructed EMSC-islet composites showed higher angiogenic potentials than naked islets, MSC-islet composites, or human endothelial cell-islet composites. This novel delivery method of porcine islets may have beneficial effects on the engraftment of transplanted islets by prevention of fragmentation and enhancement of revascularization. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. High glucose suppresses human islet insulin biosynthesis by inducing miR-133a leading to decreased polypyrimidine tract binding protein-expression

    DEFF Research Database (Denmark)

    Fred, Rikard G; Bang-Berthelsen, Claus H; Mandrup-Poulsen, Thomas

    2010-01-01

    BACKGROUND: Prolonged periods of high glucose exposure results in human islet dysfunction in vitro. The underlying mechanisms behind this effect of high glucose are, however, unknown. The polypyrimidine tract binding protein (PTB) is required for stabilization of insulin mRNA and the PTB mRNA 3......'-UTR contains binding sites for the microRNA molecules miR-133a, miR-124a and miR-146. The aim of this study was therefore to investigate whether high glucose increased the levels of these three miRNAs in association with lower PTB levels and lower insulin biosynthesis rates. METHODOLOGY...... for real-time RT-PCR analysis of miR-133a, miR-124a, miR-146, insulin mRNA and PTB mRNA contents. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. Synthetic miR-133a precursor and inhibitor were delivered to dispersed islet cells by lipofection, and PTB...

  13. The role of endothelial cells on islet function and revascularization after islet transplantation.

    Science.gov (United States)

    Del Toro-Arreola, Alicia; Robles-Murillo, Ana Karina; Daneri-Navarro, Adrian; Rivas-Carrillo, Jorge David

    2016-01-02

    Islet transplantation has become a widely accepted therapeutic option for selected patients with type 1 diabetes mellitus. However, in order to achieve insulin independence a great number of islets are often pooled from 2 to 4 pancreata donors. Mostly, it is due to the massive loss of islets immediately after transplant. The endothelium plays a key role in the function of native islets and during the revascularization process after islet transplantation. However, if a delayed revascularization occurs, even the remaining islets will also undergo to cell death and late graft dysfunction. Therefore, it is essential to understand how the signals are released from endothelial cells, which might regulate both differentiation of pancreatic progenitors and thereby maintenance of the graft function. New strategies to facilitate islet engraftment and a prompt revascularization could be designed to intervene and might lead to improve future results of islet transplantation.

  14. Obestatin enhances in vitro generation of pancreatic islets through regulation of developmental pathways.

    Directory of Open Access Journals (Sweden)

    Alessandra Baragli

    Full Text Available Availability of large amounts of in vitro generated β-cells may support replacement therapy in diabetes. However, methods to obtain β-cells from stem/progenitor cells are limited by inefficient endocrine differentiation. We have recently shown that the ghrelin gene product obestatin displays beneficial effects on pancreatic β-cell survival and function. Obestatin prevents β-cell apoptosis, preserves β-cell mass and stimulates insulin secretion in vitro and in vivo, in both normal and diabetic conditions. In the present study, we investigated whether obestatin may promote in vitro β-cell generation from mouse pancreatic islet-derived precursor cells. Treatment of cultured islets of Langerhans with obestatin (i enriched cells expressing the mesenchymal/neuronal marker nestin, which is associated with pancreatic precursors; (ii increased cell survival and reduced apoptosis during precursor selection; (iii promoted the generation of islet-like cell clusters (ICCs with increased insulin gene expression and C-peptide secretion. Furthermore, obestatin modulated the expression of fibroblast growth factor receptors (FGFRs, Notch receptors and neurogenin 3 (Ngn3 during islet-derived precursor cell selection and endocrine differentiation. These results indicate that obestatin improves the generation of functional β-cells/ICCs in vitro, suggesting implications for cell-based replacement therapy in diabetes. Moreover, obestatin may play a role in regulating pathways involved in pancreas development and regeneration.

  15. Intraportal islet oxygenation.

    Science.gov (United States)

    Suszynski, Thomas M; Avgoustiniatos, Efstathios S; Papas, Klearchos K

    2014-05-01

    Islet transplantation (IT) is a promising therapy for the treatment of diabetes. The large number of islets required to achieve insulin independence limit its cost-effectiveness and the number of patients who can be treated. It is believed that >50% of islets are lost in the immediate post-IT period. Poor oxygenation in the early post-IT period is recognized as a possible reason for islet loss and dysfunction but has not been extensively studied. Several key variables affect oxygenation in this setting, including (1) local oxygen partial pressure (pO(2)), (2) islet oxygen consumption, (3) islet size (diameter, D), and (4) presence or absence of thrombosis on the islet surface. We discuss implications of oxygen-limiting conditions on intraportal islet viability and function. Of the 4 key variables, the islet size appears to be the most important determinant of the anoxic and nonfunctional islet volume fractions. Similarly, the effect of thrombus formation on the islet surface may be substantial. At the University of Minnesota, average size distribution data from clinical alloislet preparations (n = 10) indicate that >150-µm D islets account for only ~30% of the total islet number, but >85% of the total islet volume. This suggests that improved oxygen supply to the islets may have a profound impact on islet survivability and function since most of the β-cell volume is within large islets which are most susceptible to oxygen-limiting conditions. The assumption that the liver is a suitable islet transplant site from the standpoint of oxygenation should be reconsidered. © 2014 Diabetes Technology Society.

  16. Altered TNF-Alpha, Glucose, Insulin and Amino Acids in Islets Langerhans Cultured in a Microgravity Model System

    Science.gov (United States)

    Tobin, Brian W.; Leeper-Woodford, Sandra K.; Hashemi, Brian B.; Smith, Scott M.; Sams, Clarence F.

    2001-01-01

    The present studies were designed to determine effects of a microgravity model system upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) activity and indices of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1726+/-1 17,150 u IEU) from Wistar Furth rats were treated as: 1) HARV (High Aspect Ratio Vessel cell culture) , 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. TNF-alpha (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV. These alterations in fuel homeostasis may be promulgated by gravity averaged cell culture methods or by three dimensional cell assembly.

  17. Energy dispersive X-ray microanalysis of zinc and calcium in organelles of insulin-producing cells of the mouse, rat, and a fish

    Energy Technology Data Exchange (ETDEWEB)

    Falkmer, S; Odselius, R [Lund Univ. (Sweden); Blondel, B; Prentki, M; Wollheim, C B [Geneva Univ. (Switzerland)

    1985-01-01

    By means of energy dispersive X-ray microanalysis in the scanning-transmission electron microscope, spectra were obtained from quick-frozen, cryo-ultramicrotome-cut, freeze-dried sections of insulin cells from a fish and a mouse. It was shown that both zinc and calcium are present in significant quantities in native islet cell ..beta.. granules. In the ..beta.. granules of the rat RINm5F insuloma cells calcium, but not zinc, seemed to accumulate; the zinc contents in the secretion granules of these neoplastic ..beta.. cells were probably below the detection limit.

  18. Who Should Be Considered for Islet Transplantation Alone?

    Science.gov (United States)

    Othonos, Nantia; Choudhary, Pratik

    2017-04-01

    Episodic hypoglycemia is an almost inevitable consequence of exogenous insulin treatment of type 1 diabetes, and in up to 30% of patients, this can lead to impaired awareness of hypoglycemia. This predisposes to recurrent severe hypoglycemia and has a huge impact on quality of life. Although many patients can get resolution of severe hypoglycemia through novel education and technology, some patients continue to have ongoing life-threatening hypoglycemia. Islet transplantation offers an alternative therapeutic option for these patients, in whom these conventional approaches have been unsuccessful. This review discusses the selection process of identifying suitable candidates based on recent clinical data. Results from studies of islet transplantation suggest the optimal recipient characteristics for successful islet transplantation include age >35 years, insulin requirements 85 kg. Islet transplantation can completely resolve hypoglycemia and near-normalize glucose levels, achieving insulin independence for a limited period of time in up to 40% of patients. The selection of appropriate candidates, optimizing donor selection, the use of an optimized protocol for islet cell extraction, and immunosuppression therapy have been proved to be the key criteria for a favorable outcome in islet transplantation.

  19. Insulin-Like growth factor-II (IGF-II) prevents proinflammatory cytokine-induced apoptosis and significantly improves islet survival after transplantation.

    Science.gov (United States)

    Hughes, Amy; Mohanasundaram, Daisy; Kireta, Svjetlana; Jessup, Claire F; Drogemuller, Chris J; Coates, P Toby H

    2013-03-15

    The early loss of functional islet mass (50-70%) due to apoptosis after clinical transplantation contributes to islet allograft failure. Insulin-like growth factor (IGF)-II is an antiapoptotic protein that is highly expressed in β-cells during development but rapidly decreases in postnatal life. We used an adenoviral (Ad) vector to overexpress IGF-II in isolated rat islets and investigated its antiapoptotic action against exogenous cytokines interleukin-1β- and interferon-γ-induced islet cell death in vitro. Using an immunocompromised marginal mass islet transplant model, the ability of Ad-IGF-II-transduced rat islets to restore euglycemia in nonobese diabetic/severe combined immunodeficient diabetic recipients was assessed. Ad-IGF-II transduction did not affect islet viability or function. Ad-IGF-II cytokine-treated islets exhibited decreased cell death (40% ± 2.8%) versus Ad-GFP and untransduced control islets (63.2% ± 2.5% and 53.6% ± 2.3%, respectively). Ad-IGF-II overexpression during cytokine treatment resulted in a marked reduction in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive apoptotic cells (8.3% ± 1.4%) versus Ad-GFP control (41% ± 4.2%) and untransduced control islets (46.5% ± 6.2%). Western blot analysis confirmed that IGF-II inhibits apoptosis via activation of the phosphatidylinositol 3-kinase/Akt signaling pathway. Transplantation of IGF-II overexpressing islets under the kidney capsule of diabetic mice restored euglycemia in 77.8% of recipients compared with 18.2% and 47.5% of Ad-GFP and untransduced control islet recipients, respectively (Pislet transplant outcomes in vivo. Antiapoptotic gene transfer is a potentially powerful tool to improve islet survival after transplantation.

  20. Enhancing human islet transplantation by localized release of trophic factors from PLG scaffolds.

    Science.gov (United States)

    Hlavaty, K A; Gibly, R F; Zhang, X; Rives, C B; Graham, J G; Lowe, W L; Luo, X; Shea, L D

    2014-07-01

    Islet transplantation represents a potential cure for type 1 diabetes, yet the clinical approach of intrahepatic delivery is limited by the microenvironment. Microporous scaffolds enable extrahepatic transplantation, and the microenvironment can be designed to enhance islet engraftment and function. We investigated localized trophic factor delivery in a xenogeneic human islet to mouse model of islet transplantation. Double emulsion microspheres containing exendin-4 (Ex4) or insulin-like growth factor-1 (IGF-1) were incorporated into a layered scaffold design consisting of porous outer layers for islet transplantation and a center layer for sustained factor release. Protein encapsulation and release were dependent on both the polymer concentration and the identity of the protein. Proteins retained bioactivity upon release from scaffolds in vitro. A minimal human islet mass transplanted on Ex4-releasing scaffolds demonstrated significant improvement and prolongation of graft function relative to blank scaffolds carrying no protein, and the release profile significantly impacted the duration over which the graft functioned. Ex4-releasing scaffolds enabled better glycemic control in animals subjected to an intraperitoneal glucose tolerance test. Scaffolds releasing IGF-1 lowered blood glucose levels, yet the reduction was insufficient to achieve euglycemia. Ex4-delivering scaffolds provide an extrahepatic transplantation site for modulating the islet microenvironment to enhance islet function posttransplant. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

  1. Isolated human islets require hyperoxia to maintain islet mass, metabolism, and function.

    Science.gov (United States)

    Komatsu, Hirotake; Kang, Dongyang; Medrano, Leonard; Barriga, Alyssa; Mendez, Daniel; Rawson, Jeffrey; Omori, Keiko; Ferreri, Kevin; Tai, Yu-Chong; Kandeel, Fouad; Mullen, Yoko

    2016-02-12

    Pancreatic islet transplantation has been recognized as an effective treatment for Type 1 diabetes; however, there is still plenty of room to improve transplantation efficiency. Because islets are metabolically active they require high oxygen to survive; thus hypoxia after transplant is one of the major causes of graft failure. Knowing the optimal oxygen tension for isolated islets would allow a transplant team to provide the best oxygen environment during pre- and post-transplant periods. To address this issue and begin to establish empirically determined guidelines for islet maintenance, we exposed in vitro cultured islets to different partial oxygen pressures (pO2) and assessed changes in islet volume, viability, metabolism, and function. Human islets were cultured for 7 days in different pO2 media corresponding to hypoxia (90 mmHg), normoxia (160 mmHg), and hyerpoxia (270 or 350 mmHg). Compared to normoxia and hypoxia, hyperoxia alleviated the loss of islet volume, maintaining higher islet viability and metabolism as measured by oxygen consumption and glucose-stimulated insulin secretion responses. We predict that maintaining pre- and post-transplanted islets in a hyperoxic environment will alleviate islet volume loss and maintain islet quality thereby improving transplant outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Islet-cell dysfunction induced by glucocorticoid treatment

    DEFF Research Database (Denmark)

    van Raalte, Daniël H; Kwa, Kelly A A; van Genugten, Renate E

    2013-01-01

    Glucocorticoids impair glucose tolerance by inducing insulin resistance. We investigated the dose-dependent effects of glucocorticoid treatment on islet-cell function in healthy males and studied the role of the autonomic nervous system.......Glucocorticoids impair glucose tolerance by inducing insulin resistance. We investigated the dose-dependent effects of glucocorticoid treatment on islet-cell function in healthy males and studied the role of the autonomic nervous system....

  3. Clinical Allogeneic and Autologous Islet Cell Transplantation: Update

    Directory of Open Access Journals (Sweden)

    Shinichi Matsumoto

    2011-06-01

    Full Text Available Islet cell transplantation is categorized as a β-cell replacement therapy for diabetic patients who lack the ability to secrete insulin. Allogeneic islet cell transplantation is for the treatment of type 1 diabetes, and autologous islet cell transplantation is for the prevention of surgical diabetes after a total pancreatectomy. The issues of allogeneic islet cell transplantation include poor efficacy of islet isolation, the need for multiple donor pancreata, difficulty maintaining insulin independence and undesirable side effects of immunosuppressive drugs. Those issues have been solved step by step and allogeneic islet cell transplantation is almost ready to be the standard therapy. The donor shortage will be the next issue and marginal and/or living donor islet cell transplantation might alleviate the issue. Xeno-islet cell transplantation, β-cell regeneration from human stem cells and gene induction of the naïve pancreas represent the next generation of β-cell replacement therapy. Autologous islet cell transplantation after total pancreatectomy for the treatment of chronic pancreatitis with severe abdominal pain is the standard therapy, even though only limited centers are able to perform this treatment. Remote center autologous islet cell transplantation is an attractive option for hospitals performing total pancreatectomies without the proper islet isolation facilities.

  4. Human interleukin 1β stimulates islet insulin release by a mechanism not dependent on changes in phospholipase C and protein kinase C activities or Ca2+ handling

    International Nuclear Information System (INIS)

    Welsh, N.; Nilsson, T.; Hallberg, A.; Arkhammar, P.; Berggren, P.-O.; Sandler, S.

    1989-01-01

    Isolated islets from adult rats or obese hyperglycemic (ob/ob) mice were incubated with human recombinant interleukin 1β in order to study whether the acute effects of the cytokine on islet insulin release are associated with changes in islet phospholipase C activity, Ca 2+ handling or protein phosphorylation. The cytokine stimulated insulin release both at low and high glucose concentrations during one hour incubations. In shortterm incubations ( 2+ concentration at rest nor that observed subsequent to stimulation with a high concentration of glucose. Furthermore, the endogenous protein kinase C activity, as visualized by immunoprecipitation of a 32 P-labelled substrate for this enzyme, was not altered by interleukin 1β. Separation of 32 P-labelled proteins by means of 2-dimensional gel electrophoresis failed to reveal any specific effects of the cytokine on the total protein phosphorylation activity. These results suggest that the stimulatory effects on insulin release exerted by interleukin 1β are not caused by acute activation of phospholipase C and protein kinase C or by an alternation of islet Ca 2+ handling of the B-cells. (author)

  5. Microwell Scaffolds for the Extrahepatic Transplantation of Islets of Langerhans

    Science.gov (United States)

    Buitinga, Mijke; Truckenmüller, Roman; Engelse, Marten A.; Moroni, Lorenzo; Ten Hoopen, Hetty W. M.; van Blitterswijk, Clemens A.; de Koning, Eelco JP.; van Apeldoorn, Aart A.; Karperien, Marcel

    2013-01-01

    Allogeneic islet transplantation into the liver has the potential to restore normoglycemia in patients with type 1 diabetes. However, the suboptimal microenvironment for islets in the liver is likely to be involved in the progressive islet dysfunction that is often observed post-transplantation. This study validates a novel microwell scaffold platform to be used for the extrahepatic transplantation of islet of Langerhans. Scaffolds were fabricated from either a thin polymer film or an electrospun mesh of poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) block copolymer (composition: 4000PEOT30PBT70) and were imprinted with microwells, ∼400 µm in diameter and ∼350 µm in depth. The water contact angle and water uptake were 39±2° and 52.1±4.0 wt%, respectively. The glucose flux through electrospun scaffolds was three times higher than for thin film scaffolds, indicating enhanced nutrient diffusion. Human islets cultured in microwell scaffolds for seven days showed insulin release and insulin content comparable to those of free-floating control islets. Islet morphology and insulin and glucagon expression were maintained during culture in the microwell scaffolds. Our results indicate that the microwell scaffold platform prevents islet aggregation by confinement of individual islets in separate microwells, preserves the islet’s native rounded morphology, and provides a protective environment without impairing islet functionality, making it a promising platform for use in extrahepatic islet transplantation. PMID:23737999

  6. Increased secretion of insulin and proliferation of islet {beta}-cells in rats with mesenteric lymph duct ligation

    Energy Technology Data Exchange (ETDEWEB)

    Nagino, Ko; Yokozawa, Junji; Sasaki, Yu; Matsuda, Akiko; Takeda, Hiroaki [Department of Gastroenterology, Faculty of Medicine, Yamagata University, Yamagata 990-9585 (Japan); Kawata, Sumio, E-mail: Sumio_Kawata@pref.hyogo.lg.jp [Department of Gastroenterology, Faculty of Medicine, Yamagata University, Yamagata 990-9585 (Japan); Hyogo Prefectural Nishinomiya Hospital, 13-9 Rokutanji-cho, Nishinomiya 662-0918 (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Insulin secretion was increased during the OGTT or IVGTT in mesenteric lymph duct-ligated rats. Black-Right-Pointing-Pointer Proliferation of islet {beta}-cells was upregulated in lymph duct-ligated rats. Black-Right-Pointing-Pointer Mesenteric lymph duct flow has a role in glucose metabolism. -- Abstract: Background and aims: It has been suggested that intestinal lymph flow plays an important role in insulin secretion and glucose metabolism after meals. In this study, we investigated the influence of ligation of the mesenteric lymph duct on glucose metabolism and islet {beta}-cells in rats. Methods: Male Sprague-Dawley rats (10 weeks old) were divided into two groups: one underwent ligation of the mesenteric lymph duct above the cistern (ligation group), and the other underwent a sham operation (sham group). After 1 and 2 weeks, fasting plasma concentrations of glucose, insulin, triglyceride, glucose-dependent insulinotropic polypeptide (GIP), and the active form of glucagon-like peptide-1 (GLP-1) were measured. At 2 weeks after the operation, the oral glucose tolerance test (OGTT) and intravenous glucose tolerance test (IVGTT) were performed. After the rats had been sacrificed, the insulin content of the pancreas was measured and the proliferation of {beta}-cells was assessed immunohistochemically using antibodies against insulin and Ki-67. Results: During the OGTT, the ligation group showed a significant decrease in the plasma glucose concentration at 120 min (p < 0.05) and a significant increase in the plasma insulin concentration by more than 2-fold at 15 min (p < 0.01). On the other hand, the plasma GIP concentration was significantly decreased at 60 min (p < 0.01) in the ligated group, while the active form of GLP-1 showed a significantly higher level at 90 min (1.7-fold; p < 0.05) and 120 min (2.5-fold; p < 0.01). During the IVGTT, the plasma insulin concentration in the ligation group was significantly higher at 2

  7. Drp1 guarding of the mitochondrial network is important for glucose-stimulated insulin secretion in pancreatic beta cells

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Florian; Schultz, Julia; Waterstradt, Rica; Baltrusch, Simone, E-mail: simone.baltrusch@med.uni-rostock.de

    2016-06-10

    Mitochondria form a tubular network in mammalian cells, and the mitochondrial life cycle is determined by fission, fusion and autophagy. Dynamin-related protein 1 (Drp1) has a pivotal role in these processes because it alone is able to constrict mitochondria. However, the regulation and function of Drp1 have been shown to vary between cell types. Mitochondrial morphology affects mitochondrial metabolism and function. In pancreatic beta cells mitochondrial metabolism is a key component of the glucose-induced cascade of insulin secretion. The goal of the present study was to investigate the action of Drp1 in pancreatic beta cells. For this purpose Drp1 was down-regulated by means of shDrp1 in insulin-secreting INS1 cells and mouse pancreatic islets. In INS1 cells reduced Drp1 expression resulted in diminished expression of proteins regulating mitochondrial fusion, namely mitofusin 1 and 2, and optic atrophy protein 1. Diminished mitochondrial dynamics can therefore be assumed. After down-regulation of Drp1 in INS1 cells and spread mouse islets the initially homogenous mitochondrial network characterised by a moderate level of interconnections shifted towards high heterogeneity with elongated, clustered and looped mitochondria. These morphological changes were found to correlate directly with functional alterations. Mitochondrial membrane potential and ATP generation were significantly reduced in INS1 cells after Drp1down-regulation. Finally, a significant loss of glucose-stimulated insulin secretion was demonstrated in INS1 cells and mouse pancreatic islets. In conclusion, Drp1 expression is important in pancreatic beta cells to maintain the regulation of insulin secretion. -- Highlights: •Down-regulation of Drp1 in INS1 cells reduces mitochondrial fusion protein expression. •Mitochondrial membrane potential in INS1 cells is diminished after Drp1 down-regulation. •Mitochondria become elongated after down-regulation of Drp1 in beta cells. •Down-regulation of

  8. Molecular Imaging: A Promising Tool to Monitor Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Ping Wang

    2011-01-01

    Full Text Available Replacement of insulin production by pancreatic islet transplantation has great potential as a therapy for type 1 diabetes mellitus. At present, the lack of an effective approach to islet grafts assessment limits the success of this treatment. The development of molecular imaging techniques has the potential to fulfill the goal of real-time noninvasive monitoring of the functional status and viability of the islet grafts. We review the application of a variety of imaging modalities for detecting endogenous and transplanted beta-cell mass. The review also explores the various molecular imaging strategies for assessing islet delivery, the metabolic effects on the islet grafts as well as detection of immunorejection. Here, we highlight the use of combined imaging and therapeutic interventions in islet transplantation and the in vivo monitoring of stem cells differentiation into insulin-producing cells.

  9. Intra-islet glucagon secretion and action in the regulation of glucose homeostasis.

    Directory of Open Access Journals (Sweden)

    Qinghua eWang

    2013-01-01

    Full Text Available Glucagon, a key hormone in the regulation of glucose homeostasis, acts as a counter-regulatory hormone to insulin by promoting hepatic glucose output. Under normal conditions, insulin and glucagon operate in concert to maintain the glucose level within a narrow physiological range. In diabetes, however, while insulin secretion or action is insufficient, the production and secretion of glucagon are excessive, contributing to the development of diabetic hyperglycemia. Within an islet, intra-islet insulin, in cooperation with intra-islet GABA, suppresses glucagon secretion via direct modulation of -cell intracellular signaling pathways involving Akt activation, GABA receptor phosphorylation and the receptor plasma membrane translocation, while intra-islet glucagon plays an important role in modulating β-cell function and insulin secretion. Defects in the insulin-glucagon fine-tuning machinery may result in β-cell glucose incompetence, leading to unsuppressed glucagon secretion and subsequent hyperglycemia, which often occur under extreme conditions of glucose influx or efflux. Therefore, deciphering the precise molecular mechanisms underlying glucagon secretion and action will facilitate our understanding of glucagon physiology, in particular, its role in regulating islet β-cell function, and hence the mechanisms behind body glucose homeostasis.

  10. Inflammatory Response in Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Mazhar A. Kanak

    2014-01-01

    Full Text Available Islet cell transplantation is a promising beta cell replacement therapy for patients with brittle type 1 diabetes as well as refractory chronic pancreatitis. Despite the vast advancements made in this field, challenges still remain in achieving high frequency and long-term successful transplant outcomes. Here we review recent advances in understanding the role of inflammation in islet transplantation and development of strategies to prevent damage to islets from inflammation. The inflammatory response associated with islets has been recognized as the primary cause of early damage to islets and graft loss after transplantation. Details on cell signaling pathways in islets triggered by cytokines and harmful inflammatory events during pancreas procurement, pancreas preservation, islet isolation, and islet infusion are presented. Robust control of pre- and peritransplant islet inflammation could improve posttransplant islet survival and in turn enhance the benefits of islet cell transplantation for patients who are insulin dependent. We discuss several potent anti-inflammatory strategies that show promise for improving islet engraftment. Further understanding of molecular mechanisms involved in the inflammatory response will provide the basis for developing potent therapeutic strategies for enhancing the quality and success of islet transplantation.

  11. Inflammatory Response in Islet Transplantation

    Science.gov (United States)

    Kanak, Mazhar A.; Kunnathodi, Faisal; Lawrence, Michael C.; Levy, Marlon F.

    2014-01-01

    Islet cell transplantation is a promising beta cell replacement therapy for patients with brittle type 1 diabetes as well as refractory chronic pancreatitis. Despite the vast advancements made in this field, challenges still remain in achieving high frequency and long-term successful transplant outcomes. Here we review recent advances in understanding the role of inflammation in islet transplantation and development of strategies to prevent damage to islets from inflammation. The inflammatory response associated with islets has been recognized as the primary cause of early damage to islets and graft loss after transplantation. Details on cell signaling pathways in islets triggered by cytokines and harmful inflammatory events during pancreas procurement, pancreas preservation, islet isolation, and islet infusion are presented. Robust control of pre- and peritransplant islet inflammation could improve posttransplant islet survival and in turn enhance the benefits of islet cell transplantation for patients who are insulin dependent. We discuss several potent anti-inflammatory strategies that show promise for improving islet engraftment. Further understanding of molecular mechanisms involved in the inflammatory response will provide the basis for developing potent therapeutic strategies for enhancing the quality and success of islet transplantation. PMID:24883060

  12. Influence of High Aspect Ratio Vessel Cell Culture on TNF-Alpha, Insulin Secretion and Glucose Homeostasis in Pancreatic Islets of Langerhans from Wistar Furth Rats

    Science.gov (United States)

    Tobin, Brian W.a; Leeper-Woodford, Sandra K.

    1999-01-01

    The present studies were carried out to determine the influence of a ground based microgravity paradigm, utilizing the High Aspect Ratio Vessel (HARV) cell culture upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) production of pancreatic islets of Langerhans. An additional aim was to elucidate alterations in insulin secretion and glucose utilization using the HARV low shear, gravity averaged vector, cell culture technique. Islets were isolated (1726 +/- 117, 150 micron islet equivalent units) from Wistar Furth rats and assigned to four treatment groups: 1) HARV, 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. Following 48 hours of culture, insulin concentration was increased in both HARV and static cultures (palpha (L929 cytotoxicity assay) and was measured at selected time points for 48 hours. TNF-alpha was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha is associated with a decreased insulin secretion is intriguing, both as it relates to in-flight investigations, and as it may provide insight into the pathophysiology of Type I and Type 11 diabetes. Glucose concentration in islet medium was lesser throughout the experiment in static cultures, suggesting a decreased reliance upon glucose as a metabolic substrate in the islets cultured in HARVS. In conclusion, the present studies demonstrate alterations in LPS induced TNF-alpha production of pancreatic islets of Langerhans, favoring a lesser TNF production in the microgravity HARV paradigm. Additionally, alterations in fuel homeostasis may be promulgated by HARV culture. The clinical and physiological significance of these observations remains to be determined.

  13. Pancreatic Islet Cell Transplantation: A new era in transplantation

    OpenAIRE

    Warnock, Garth L.; Rajotte, Ray V.

    1992-01-01

    Transplantation of insulin-producing tissue offers a physiologic approach to restoration of glycemic control. Whereas transplantation of vascularized pancreatic grafts has recently achieved encouraging results, pancreatic islet cell transplantation holds the promise of low morbidity and reduced requirements for agressive immunosuppression for recipients. Islet cell transplantation was recently demonstrated to induce euglycemia with insulin independence.

  14. Loss of end-differentiated β-cell phenotype following pancreatic islet transplantation.

    Science.gov (United States)

    Anderson, S J; White, M G; Armour, S L; Maheshwari, R; Tiniakos, D; Muller, Y D; Berishvili, E; Berney, T; Shaw, J A M

    2018-03-01

    Replacement of pancreatic β-cells through deceased donor islet transplantation is a proven therapy for preventing recurrent life-threatening hypoglycemia in type 1 diabetes. Although near-normal glucose levels and insulin independence can be maintained for many years following successful islet transplantation, restoration of normal functional β-cell mass has remained elusive. It has recently been proposed that dedifferentiation/plasticity towards other endocrine phenotypes may play an important role in stress-induced β-cell dysfunction in type 2 diabetes. Here we report loss of end-differentiated β-cell phenotype in 2 intraportal islet allotransplant recipients. Despite excellent graft function and sustained insulin independence, all examined insulin-positive cells had lost expression of the end-differentiation marker, urocortin-3, or appeared to co-express the α-cell marker, glucagon. In contrast, no insulin + /urocortin-3 - cells were seen in nondiabetic deceased donor control pancreatic islets. Loss of end-differentiated phenotype may facilitate β-cell survival during the stresses associated with islet isolation and culture, in addition to sustained hypoxia following engraftment. As further refinements in islet isolation and culture are made in parallel with exploration of alternative β-cell sources, graft sites, and ultimately fully vascularized bioengineered insulin-secreting microtissues, differentiation status immunostaining provides a novel tool to assess whether fully mature β-cell phenotype has been maintained. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  15. Zn2+ chelation by serum albumin improves hexameric Zn2+-insulin dissociation into monomers after exocytosis.

    Directory of Open Access Journals (Sweden)

    José A G Pertusa

    Full Text Available β-cells release hexameric Zn2+-insulin into the extracellular space, but monomeric Zn2+-free insulin appears to be the only biologically active form. The mechanisms implicated in dissociation of the hexamer remain unclear, but they seem to be Zn2+ concentration-dependent. In this study, we investigate the influence of albumin binding to Zn2+ on Zn2+-insulin dissociation into Zn2+-free insulin and its physiological, methodological and therapeutic relevance. Glucose and K+-induced insulin release were analyzed in isolated mouse islets by static incubation and perifusion experiments in the presence and absence of albumin and Zn2+ chelators. Insulin tolerance tests were performed in rats using different insulin solutions with and without Zn2+ and/or albumin. Albumin-free buffer does not alter quantification by RIA of Zn2+-free insulin but strongly affects RIA measurements of Zn2+-insulin. In contrast, accurate determination of Zn2+-insulin was obtained only when bovine serum albumin or Zn2+ chelators were present in the assay buffer solution. Albumin and Zn2+ chelators do not modify insulin release but do affect insulin determination. Preincubation with albumin or Zn2+ chelators promotes the conversion of "slow" Zn2+-insulin into "fast" insulin. Consequently, insulin diffusion from large islets is ameliorated in the presence of Zn2+ chelators. These observations support the notion that the Zn2+-binding properties of albumin improve the dissociation of Zn2+-insulin into subunits after exocytosis, which may be useful in insulin determination, insulin pharmacokinetic assays and islet transplantation.

  16. Glucose activates prenyltransferases in pancreatic islet {beta}-cells

    Energy Technology Data Exchange (ETDEWEB)

    Goalstone, Marc [Department of Medicine, University of Colorado, VA Medical Center, Denver, CO 80220 (United States); Kamath, Vasudeva [Department of Pharmaceutical Sciences, Wayne State University, VA Medical Center, Detroit, MI 48201 (United States); Kowluru, Anjaneyulu, E-mail: akowluru@med.wayne.edu [Department of Pharmaceutical Sciences, Wayne State University, VA Medical Center, Detroit, MI 48201 (United States)

    2010-01-01

    A growing body of evidence implicates small G-proteins [e.g., Cdc42 and Rac1] in glucose-stimulated insulin secretion [GSIS] in the islet {beta}-cell. These signaling proteins undergo post-translational modifications [e.g., prenylation] at their C-terminal cysteine residue and appear to be essential for the transport and fusion of insulin-containing secretory granules with the plasma membrane and the exocytotic secretion of insulin. However, potential regulation of the prenylating enzymes by physiological insulin secretogues [e.g., glucose] has not been investigated thus far. Herein, we report immunological localization, sub-cellular distribution and regulation of farnesyltransferases [FTases] and geranylgeranyltransferase [GGTase] by glucose in insulin-secreting INS 832/13 {beta}-cells and normal rat islets. Our findings suggest that an insulinotropic concentration of glucose [20 mM] markedly stimulated the expression of the {alpha}-subunits of FTase/GGTase-1, but not the {beta}-subunits of FTase or GGTase-1 without significantly affecting the predominantly cytosolic distribution of these holoenzymes in INS 832/13 cells and rodent islets. Under these conditions, glucose significantly stimulated [2.5- to 4.0-fold over basal] the activities of both FTase and GGTase-1 in both cell types. Together, these findings provide the first evidence to suggest that GSIS involves activation of the endogenous islet prenyltransferases by glucose, culminating in the activation of their respective G-protein substrates, which is necessary for cytoskeletal rearrangement, vesicular transport, fusion and secretion of insulin.

  17. Glucose activates prenyltransferases in pancreatic islet β-cells

    International Nuclear Information System (INIS)

    Goalstone, Marc; Kamath, Vasudeva; Kowluru, Anjaneyulu

    2010-01-01

    A growing body of evidence implicates small G-proteins [e.g., Cdc42 and Rac1] in glucose-stimulated insulin secretion [GSIS] in the islet β-cell. These signaling proteins undergo post-translational modifications [e.g., prenylation] at their C-terminal cysteine residue and appear to be essential for the transport and fusion of insulin-containing secretory granules with the plasma membrane and the exocytotic secretion of insulin. However, potential regulation of the prenylating enzymes by physiological insulin secretogues [e.g., glucose] has not been investigated thus far. Herein, we report immunological localization, sub-cellular distribution and regulation of farnesyltransferases [FTases] and geranylgeranyltransferase [GGTase] by glucose in insulin-secreting INS 832/13 β-cells and normal rat islets. Our findings suggest that an insulinotropic concentration of glucose [20 mM] markedly stimulated the expression of the α-subunits of FTase/GGTase-1, but not the β-subunits of FTase or GGTase-1 without significantly affecting the predominantly cytosolic distribution of these holoenzymes in INS 832/13 cells and rodent islets. Under these conditions, glucose significantly stimulated [2.5- to 4.0-fold over basal] the activities of both FTase and GGTase-1 in both cell types. Together, these findings provide the first evidence to suggest that GSIS involves activation of the endogenous islet prenyltransferases by glucose, culminating in the activation of their respective G-protein substrates, which is necessary for cytoskeletal rearrangement, vesicular transport, fusion and secretion of insulin.

  18. Long-Term Follow-Up of the Edmonton Protocol of Islet Transplantation in the United States.

    Science.gov (United States)

    Brennan, D C; Kopetskie, H A; Sayre, P H; Alejandro, R; Cagliero, E; Shapiro, A M J; Goldstein, J S; DesMarais, M R; Booher, S; Bianchine, P J

    2016-02-01

    We report the long-term follow-up of the efficacy and safety of islet transplantation in seven type 1 diabetic subjects from the United States enrolled in the multicenter international Edmonton Protocol who had persistent islet function after completion of the Edmonton Protocol. Subjects were followed up to 12 years with serial testing for sustained islet allograft function as measured by C-peptide. All seven subjects demonstrated continued islet function longer than a decade from the time of first islet transplantation. One subject remained insulin independent without the need for diabetic medications or supplemental transplants. One subject who was insulin-independent for over 8 years experienced graft failure 10.9 years after the first islet transplant. The remaining six subjects demonstrated continued islet function upon trial completion, although three had received a supplemental islet transplant each. At trial completion, five subjects were receiving insulin and two remained insulin independent, although one was treated with liraglutide. The median hemoglobin A1c was 6.3% (45 mmol/mol). All subjects experienced progressive decline in the C-peptide/glucose ratio. No patients experienced severe hypoglycemia, opportunistic infection, or lymphoma. Thus, although the rate and duration of insulin independence was low, the Edmonton Protocol was safe in the long term. Alternative approaches to islet transplantation are under investigation. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  19. Organ culture studies for pancreatic islet transplantation

    International Nuclear Information System (INIS)

    Reemtsma, K.; Weber, C.J.; Pi-Sunyer, F.X.; Lerner, R.; Zimmerman, E.; Hardy, M.A.

    1979-01-01

    Data support the usefulness of tissue culture in isolation and preservation of islets prior to transplantation. Rodent islet viability in culture was demonstrated histologically and by functional analyses of hormone production. For reasons that remain to be defined, acinar cells disappeared rapidly in tissue culture, yielding an implant preparation relatively rich in islets and devoid of pancreatic exocrine elements. Isografts of cultured and noncultured islets were well tolerated intraperitoneally and intramuscularly; and prompt and lasting reversal of short- and long-standing experimental diabetes was observed regularly. In vitro studies of rodent islet viability after immunosuppressive treatment of donors or islet cultures showed insulin production comparable to that of control experiments, suggesting that immunologic modification of donors or islets might be feasible in eventual human islet allotransplantation

  20. In Vivo Imaging of Transplanted Pancreatic Islets

    Directory of Open Access Journals (Sweden)

    Donghee Kim

    2018-01-01

    Full Text Available The beta-cells in the islets of Langerhans in the pancreas secrete insulin and play an important role in glucose homeostasis. Diabetes, characterized by hyperglycemia, results from an absolute or a relative deficiency of the pancreatic beta-cell mass. Islet transplantation has been considered to be a useful therapeutic approach, but it is largely unsuccessful because most of the transplanted islets are lost in the early stage of transplantation. To evaluate the efficacy of intervention methods for the improvement of islet survival, monitoring of the functional islet mass is needed. Various techniques to image and track transplanted islets have been investigated to assess islets after transplantation. In this review, recent progresses in imaging methods to visualize islets are discussed.

  1. Sequential kidney/islet transplantation using prednisone-free immunosuppression.

    Science.gov (United States)

    Kaufman, Dixon B; Baker, Marshall S; Chen, Xiaojuan; Leventhal, Joseph R; Stuart, Frank P

    2002-08-01

    Islet transplantation is becoming established as a treatment option for type I diabetes in select patients. Individuals with type I diabetes who have previously received a successful kidney allograft may be good candidates for islet transplantation. They have already assumed the risks of chronic immunosuppression, so the added procedural risk of a subsequent islet transplant would be minimal. Furthermore, because of the preimmunosuppressed state it is possible that islet-after-kidney transplantation may result in a more efficient early islet engraftment. Consequently, insulin independence might be achieved with significantly fewer islets than the approximately 8-10,000 islet equivalents/kg/b.w. currently required. A mass that usually demands two or more cadaveric donors. A case of successful islet-after-kidney transplantation is described using the steroid-free Edmonton immunosuppression protocol. Characteristics of the final islet product are: a) islet equivalents: 265,888 (4100 islet equivalents/kg/b.w.); b) islet purity: 75-80%; c) viability: >95% (trypan blue exclusion); and d) mean islet potency (static low-high glucose challenge): 4.16 +/- 1.91-fold increase. Post-transplant the patient's hypoglycemic episodes abated. Exogenous insulin requirements were eliminated at week 12 post-transplant as basal and Ensure (Abbott Laboratories, Abbott Park, IL, USA) oral glucose stimulated C-peptide levels peaked and stabilized. Twenty-four-hour continuous glucose monitoring confirmed moment-to-moment glycemic control, and periodic nonfasting finger stick glucose determinations over the next month confirmed glycemia was controlled. Hemoglobin A1c levels declined from a pretransplant level of 6.9% to 5.3%. Renal allograft function remained changed.

  2. A novel insulinotropic mechanism of whole grain-derived γ-oryzanol via the suppression of local dopamine D2 receptor signalling in mouse islet.

    Science.gov (United States)

    Kozuka, Chisayo; Sunagawa, Sumito; Ueda, Rei; Higa, Moritake; Ohshiro, Yuzuru; Tanaka, Hideaki; Shimizu-Okabe, Chigusa; Takayama, Chitoshi; Matsushita, Masayuki; Tsutsui, Masato; Ishiuchi, Shogo; Nakata, Masanori; Yada, Toshihiko; Miyazaki, Jun-Ichi; Oyadomari, Seiichi; Shimabukuro, Michio; Masuzaki, Hiroaki

    2015-07-03

    γ-Oryzanol, derived from unrefined rice, attenuated the preference for dietary fat in mice, by decreasing hypothalamic endoplasmic reticulum stress. However, no peripheral mechanisms, whereby γ-oryzanol could ameliorate glucose dyshomeostasis were explored. Dopamine D 2 receptor signalling locally attenuates insulin secretion in pancreatic islets, presumably via decreased levels of intracellular cAMP. We therefore hypothesized that γ-oryzanol would improve high-fat diet (HFD)-induced dysfunction of islets through the suppression of local D 2 receptor signalling. Glucose metabolism and regulation of molecules involved in D 2 receptor signalling in pancreatic islets were investigated in male C57BL/6J mice, fed HFD and treated with γ-oryzanol . In isolated murine islets and the beta cell line, MIN6 , the effects of γ-oryzanol on glucose-stimulated insulin secretion (GSIS) was analysed using siRNA for D 2 receptors and a variety of compounds which alter D 2 receptor signalling. In islets, γ-oryzanol enhanced GSIS via the activation of the cAMP/PKA pathway. Expression of molecules involved in D 2 receptor signalling was increased in islets from HFD-fed mice, which were reciprocally decreased by γ-oryzanol. Experiments with siRNA for D 2 receptors and D 2 receptor ligands in vitro suggest that γ-oryzanol suppressed D 2 receptor signalling and augmented GSIS. γ-Oryzanol exhibited unique anti-diabetic properties. The unexpected effects of γ-oryzanol on D 2 receptor signalling in islets may provide a novel; natural food-based, approach to anti-diabetic therapy. © 2015 The British Pharmacological Society.

  3. Small Islets Transplantation Superiority to Large Ones: Implications from Islet Microcirculation and Revascularization

    Directory of Open Access Journals (Sweden)

    Wenjuan Li

    2014-01-01

    Full Text Available Pancreatic islet transplantation is a promising therapy to regain glycemic control in diabetic patients. The selection of ideal grafts is the basis to guarantee short-term effectivity and longevity of the transplanted islets. Contradictory to the traditional notion, recent findings implied the superiority of small islets for better transplantation outcomes rather than the large and intact ones. However, the mechanisms remain to be elucidated. Recent evidences emphasized the major impact of microcirculation on islet β-cell mass and function. And potentials in islet graft revascularization are crucial for their survival and preserved function in the recipient. In this study, we verified the distinct histological phenotype and functionality of small islets versus large ones both in vitro and in vivo. With efforts to exploring the differences in microcirculation and revascularization of islet grafts, we further evaluated local expressions of angiotensin and vascular endothelial growth factor A (VEGF-A at different levels. Our findings reveal that, apart from the higher density of insulin-producing β-cells, small islets express less angiotensin and more angiotrophic VEGF-A. We therefore hypothesized a logical explanation of the small islet superiority for transplantation outcome from the aspects of facilitated microcirculation and revascularization intrinsically in small islets.

  4. 3H-cyclosporine internalization and secretion by human fetal pancreatic islets

    International Nuclear Information System (INIS)

    Formby, B.; Walker, L.; Peterson, C.M.

    1988-01-01

    Human fetal pancreatic islets were isolated from 16- to 20-week-old fetuses by a collagenase technique and cultured 48 hr in RPMI 1640 containing 10% human adult serum and unlabeled 0 to 5 micrograms cyclosporine A (CsA)/ml. Insulin secretory capacity of human fetal islets was expressed as a fractional stimulatory ratio FSR = F2/F1 of the fractional secretion rates during two successive 1 hr static incubations first with 2 mM glucose (F1) to stabilize secretion followed by maximal stimulus, i.e., 25 mM glucose plus 10 mM L-leucine and 10 mM L-arginine (F2). Unlabeled CsA at the above concentrations had no significant effects on the insulin secretory capacity expressed by FSR-values. Studies of net uptake of 3H-CsA by islets cultured for varying periods up to 40 hr and expressed as picomole 3H-CsA per picomole islet insulin content demonstrated that uptake rate was slow and did not reach isotopic equilibrium over the 40 hr of culture. When isolated fetal islets were cultured for 48 hr in the presence of 3H-CsA and varying concentrations of unlabeled CsA it was found during two successive 1 hr static incubations that fetal islets secrete insulin concomitantly with 3H-CsA following maximal stimulus for secretion. An optimal secretory molar ratio of 3H-CsA to insulin of 4.0 +/- 1.3 (n = 7) was found after islets were cultured 48 hr in the presence of a saturating 2.128 micrograms 3H-CsA per milliliter culture medium. In three successive 30-min static incubations of 3H-CsA loaded islets, first with low glucose, followed by high glucose plus L-arginine and L-leucine, and finally with high glucose plus L-arginine and L-leucine and 10 mM theophylline, the proportional fractional secretion rates of insulin and 3H-CsA were of the same magnitude

  5. A mouse model for monitoring islet cell genesis and developing therapies for diabetes

    Directory of Open Access Journals (Sweden)

    Yoshinori Shimajiri

    2011-03-01

    Transient expression of the transcription factor neurogenin-3 marks progenitor cells in the pancreas as they differentiate into islet cells. We developed a transgenic mouse line in which the surrogate markers secreted alkaline phosphatase (SeAP and enhanced green florescent protein (EGFP can be used to monitor neurogenin-3 expression, and thus islet cell genesis. In transgenic embryos, cells expressing EGFP lined the pancreatic ducts. SeAP was readily detectable in embryos, in the media of cultured embryonic pancreases and in the serum of adult animals. Treatment with the γ-secretase inhibitor DAPT, which blocks Notch signaling, enhanced SeAP secretion rates and increased the number of EGFP-expressing cells as assayed by fluorescence-activated cell sorting (FACS and immunohistochemistry in cultured pancreases from embryos at embryonic day 11.5, but not in pancreases harvested 1 day later. By contrast, treatment with growth differentiation factor 11 (GDF11 reduced SeAP secretion rates. In adult mice, partial pancreatectomy decreased, whereas duct ligation increased, circulating SeAP levels. This model will be useful for studying signals involved in islet cell genesis in vivo and developing therapies that induce this process.

  6. Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects after prolonged culture in a low non-stimulating glucose concentration.

    Science.gov (United States)

    Roma, L P; Pascal, S M; Duprez, J; Jonas, J-C

    2012-08-01

    Pancreatic beta cells chronically exposed to low glucose concentrations show signs of oxidative stress, loss of glucose-stimulated insulin secretion (GSIS) and increased apoptosis. Our aim was to confirm the role of mitochondrial oxidative stress in rat islet cell apoptosis under these culture conditions and to evaluate whether its reduction similarly improves survival and GSIS. Apoptosis, oxidative stress-response gene mRNA expression and glucose-induced stimulation of mitochondrial metabolism, intracellular Ca(2+) concentration and insulin secretion were measured in male Wistar rat islets cultured for 1 week in RPMI medium containing 5-10 mmol/l glucose with or without manganese(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP) or N-acetyl-L-: cysteine (NAC). Oxidative stress was measured in islet cell clusters cultured under similar conditions using cytosolic and mitochondrial redox-sensitive green fluorescent protein (roGFP1/mt-roGFP1). Prolonged culture in 5 vs 10 mmol/l glucose increased mt-roGFP1 (but not roGFP1) oxidation followed by beta cell apoptosis and loss of GSIS resulting from reduced insulin content, mitochondrial metabolism, Ca(2+) influx and Ca(2+)-induced secretion. Tolbutamide-induced, but not high K(+)-induced, Ca(2+) influx was also suppressed. Under these conditions, MnTBAP, but not NAC, triggered parallel ~50-70% reductions in mt-roGFP1 oxidation and beta cell apoptosis, but failed to protect against the loss of GSIS despite significant improvement in glucose-induced and tolbutamide-induced Ca(2+) influx. Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects during culture in a low glucose concentration. Thus, targeting beta cell survival may not be sufficient to restore insulin secretion when beta cells suffer from prolonged mitochondrial oxidative stress, e.g. in the context of reduced glucose metabolism.

  7. Stem Cells as a Tool to Improve Outcomes of Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Emily Sims

    2012-01-01

    Full Text Available The publication of the promising results of the Edmonton protocol in 2000 generated optimism for islet transplantation as a potential cure for Type 1 Diabetes Mellitus. Unfortunately, follow-up data revealed that less than 10% of patients achieved long-term insulin independence. More recent data from other large trials like the Collaborative Islet Transplant Registry show incremental improvement with 44% of islet transplant recipients maintaining insulin independence at three years of follow-up. Multiple underlying issues have been identified that contribute to islet graft failure, and newer research has attempted to address these problems. Stem cells have been utilized not only as a functional replacement for β cells, but also as companion or supportive cells to address a variety of different obstacles that prevent ideal graft viability and function. In this paper, we outline the manners in which stem cells have been applied to address barriers to the achievement of long-term insulin independence following islet transplantation.

  8. Has the gap between pancreas and islet transplantation closed?

    Science.gov (United States)

    Niclauss, Nadja; Morel, Philippe; Berney, Thierry

    2014-09-27

    Both pancreas and islet transplantations are therapeutic options for complicated type 1 diabetes. Until recent years, outcomes of islet transplantation have been significantly inferior to those of whole pancreas. Islet transplantation is primarily performed alone in patients with severe hypoglycemia, and recent registry reports have suggested that results of islet transplantation alone in this indication may be about to match those of pancreas transplant alone in insulin independence. Figures of 50% insulin independence at 5 years for either procedure have been cited. In this article, we address the question whether islet transplantation has indeed bridged the gap with whole pancreas. Looking at the evidence to answer this question, we propose that although pancreas may still be more efficient in taking recipients off insulin than islets, there are in fact numerous "gaps" separating both procedures that must be taken into the equation. These "gaps" relate to organ utilization, organ allocation, indication for transplantation, and morbidity. In-depth analysis reveals that islet transplantation, in fact, has an edge on whole pancreas in some of these aspects. Accordingly, attempts should be made to bridge these gaps from both sides to achieve the same level of success with either procedure. More realistically, it is likely that some of these gaps will remain and that both procedures will coexist and complement each other, to ensure that β cell replacement can be successfully implemented in the greatest possible number of patients with type 1 diabetes.

  9. Human Monoclonal Islet Cell Antibodies From a Patient with Insulin- Dependent Diabetes Mellitus Reveal Glutamate Decarboxylase as the Target Antigen

    Science.gov (United States)

    Richter, Wiltrud; Endl, Josef; Eiermann, Thomas H.; Brandt, Michael; Kientsch-Engel, Rosemarie; Thivolet, Charles; Jungfer, Herbert; Scherbaum, Werner A.

    1992-09-01

    The autoimmune phenomena associated with destruction of the β cell in pancreatic islets and development of type 1 (insulin-dependent) diabetes mellitus (IDDM) include circulating islet cell antibodies. We have immortalized peripheral blood lymphocytes from prediabetic individuals and patients with newly diagnosed IDDM by Epstein-Barr virus transformation. IgG-positive cells were selected by anti-human IgG-coupled magnetic beads and expanded in cell culture. Supernatants were screened for cytoplasmic islet cell antibodies using the conventional indirect immunofluorescence test on cryostat sections of human pancreas. Six islet cell-specific B-cell lines, originating from a patient with newly diagnosed IDDM, could be stabilized on a monoclonal level. All six monoclonal islet cell antibodies (MICA 1-6) were of the IgG class. None of the MICA reacted with human thyroid, adrenal gland, anterior pituitary, liver, lung, stomach, and intestine tissues but all six reacted with pancreatic islets of different mammalian species and, in addition, with neurons of rat cerebellar cortex. MICA 1-6 were shown to recognize four distinct antigenic epitopes in islets. Islet cell antibody-positive diabetic sera but not normal human sera blocked the binding of the monoclonal antibodies to their target epitopes. Immunoprecipitation of 35S-labeled human islet cell extracts revealed that a protein of identical size to the enzyme glutamate decarboxylase (EC 4.1.1.15) was a target of all MICA. Furthermore, antigen immunotrapped by the MICA from brain homogenates showed glutamate decarboxylase enzyme activity. MICA 1-6 therefore reveal glutamate decarboxylase as the predominant target antigen of cytoplasmic islet cell autoantibodies in a patient with newly diagnosed IDDM.

  10. In Vivo Monitoring of Pancreatic β-Cells in a Transgenic Mouse Model

    Directory of Open Access Journals (Sweden)

    Steven J. Smith

    2006-04-01

    Full Text Available We generated a transgenic mouse model (RIP-luc for the in vivo monitoring of pancreatic islet mass and function in response to metabolic disease. Using the rat insulin promoter fused to firefly luciferase, and noninvasive technology to detect luciferase activity, we tracked changes in reporter signal during metabolic disease states and correlated the changes in luciferase signal with metabolic status of the mouse. Transgene expression was found to be specific to the pancreatic islets in this transgenic model. Basal transgene expression was tracked in male and female mice fed either a chow or a high-fat diet and in response to treatment with streptozotocin. Pancreatic bioluminescent signal increased in mice fed a high-fat diet compared with chow-fed animals. In a model of chemically induced diabetes, the bioluminescent signal decreased in accordance with the onset of diabetes and reduction of islet β-cell number. Preliminary studies using islets transplanted from this transgenic model suggest that in vivo image analysis can also be used to monitor transplanted islet viability and survival in the host. This transgenic model is a useful tool for in vivo studies of pancreatic β-cells and as a donor for islet transplantation studies.

  11. High-fat diet with stress impaired islets' insulin secretion by reducing plasma estradiol and pancreatic GLUT2 protein levels in rats' proestrus phase.

    Science.gov (United States)

    Salimi, M; Zardooz, H; Khodagholi, F; Rostamkhani, F; Shaerzadeh, F

    2016-10-01

    This study was conducted to determine whether two estrus phases (proestrus and diestrus) in female rats may influence the metabolic response to a high-fat diet and/or stress, focusing on pancreatic insulin secretion and content. Animals were divided into high-fat and normal diet groups, then each group was subdivided into stress and non-stress groups, and finally, each one of these was divided into proestrus and diestrus subgroups. At the end of high-fat diet treatment, foot-shock stress was applied to the animals. Then, blood samples were taken to measure plasma factors. Finally, the pancreas was removed for determination of glucose transporter 2 (GLUT2) protein levels and assessment of insulin content and secretion of the isolated islets. In the normal and high-fat diet groups, stress increased plasma corticosterone concentration in both phases. In both study phases, high-fat diet consumption decreased estradiol and increased leptin plasma levels. In the high-fat diet group in response to high glucose concentration, a reduction in insulin secretion was observed in the proestrus phase compared with the same phase in the normal diet group in the presence and absence of stress. Also, high-fat diet decreased the insulin content of islets in the proestrus phase compared with the normal diet. High-fat diet and/or stress caused a reduction in islet GLUT2 protein levels in both phases. In conclusion, it seems possible that high-fat diet alone or combined with foot-shock, predispose female rats to impaired insulin secretion, at least in part, by interfering with estradiol levels in the proestrus phase and decreasing pancreatic GLUT2 protein levels.

  12. Pseudoislets as primary islet replacements for research: report on a symposium at King's College London, London UK.

    Science.gov (United States)

    Persaud, Shanta J; Arden, Catherine; Bergsten, Peter; Bone, Adrian J; Brown, James; Dunmore, Simon; Harrison, Moira; Hauge-Evans, Astrid; Kelly, Catriona; King, Aileen; Maffucci, Tania; Marriott, Claire E; McClenaghan, Neville; Morgan, Noel G; Reers, Christina; Russell, Mark A; Turner, Mark D; Willoughby, Emma; Younis, Mustafa Y G; Zhi, Z L; Jones, Peter M

    2010-01-01

    Laboratory-based research aimed at understanding processes regulating insulin secretion and mechanisms underlying β-cell dysfunction and loss in diabetes often makes use of rodents, as these processes are in many respects similar between rats/mice and humans. Indeed, a rough calculation suggests that islets have been isolated from as many as 150,000 rodents to generate the data contained within papers published in 2009 and the first four months of 2010. Rodent use for islet isolation has been mitigated, to a certain extent, by the availability of a variety of insulin-secreting cell lines that are used by researchers world-wide. However, when maintained as monolayers the cell lines do not replicate the robust, sustained secretory responses of primary islets which limits their usefulness as islet surrogates. On the other hand, there have been several reports that configuration of MIN6 β-cells, derived from a mouse insulinoma, as three-dimensional cell clusters termed ‘pseudoislets’ largely recapitulates the function of primary islet β-cells. The Diabetes Research Group at King’s College London has been using the MIN6 pseudoislet model for over a decade and they hosted a symposium on “Pseudoislets as primary islet replacements for research”, which was funded by the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), in London on 15th and 16th April 2010. This small, focused meeting was conceived as an opportunity to consolidate information on experiences of working with pseudoislets between different UK labs, and to introduce the theory and practice of pseudoislet culture to laboratories working with islets and/or β-cell lines but who do not currently use pseudoislets. This short review summarizes the background to the development of the cell line-derived pseudoislet model, the key messages arising from the symposium and emerging themes for future pseudoislet research.

  13. Rubidium uptake by mouse pancreatic islets exposed to 6-hydroxydopamine, ninhydrin, or other generators of hydroxyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    Grankvist, K.; Sehlin, J.; Taeljedal, I.-B.

    1986-01-01

    The purpose was to study the toxicity of drugs known to generate free radicals on isolated pancreatic islets. The accumulation of /sup 86/Rb/sup +/ by mouse pancreatic islets was measured in vitro. Exposing the islets to 6-hydroxydopamine, minhydrin, or phenazine methosulphate + NADH inhibited the Rb/sup +/ uptake, whereas paraquat or acetylphenylhydrazine had no effect. This effect of 6-hydroxydopamine was prevented by either of the hydroxyl radical scavengers, sodium benzoate and mannitol, but not by the non-scavenger urea; ninhydrin was partially protected against by mannitol but not by benzoate. Protection against 6-hydroxydopamine was also afforded by D-glucose but not by L-glucose or 3-O-methyl-D-glucose; none of the sugars protected against ninhydrin. In damaging islet beta-cells and in being protected against by D-glucose, 6-hydroxydopamine closely resembles the diabetogenic drug, alloxan. It is suggested that protection against alloxan may involve both glucose metabolism and the interaction of glucose with its membrane-located carrier, while protection against 6-hydroxydopamine appears to be unrelated to the hexose carrier mechanism.

  14. SAD-A kinase controls islet β-cell size and function as a mediator of mTORC1 signaling.

    Science.gov (United States)

    Nie, Jia; Liu, Xiaolei; Lilley, Brendan N; Zhang, Hai; Pan, Y Albert; Kimball, Scot R; Zhang, Jun; Zhang, Weiping; Wang, Li; Jefferson, Leonard S; Sanes, Joshua R; Han, Xiao; Shi, Yuguang

    2013-08-20

    The mammalian target of rapamycin (mTOR) plays an important role in controlling islet β-cell function. However, the underlying molecular mechanisms remain poorly elucidated. Synapses of amphids defective kinase-A (SAD-A) is a 5' adenosine monophosphate-activated protein kinase-related protein kinase that is exclusively expressed in pancreas and brain. In this study, we investigated a role of the kinase in regulating pancreatic β-cell morphology and function as a mediator of mTOR complex 1 (mTORC1) signaling. We show that global SAD-A deletion leads to defective glucose-stimulated insulin secretion and petite islets, which are reminiscent of the defects in mice with global deletion of ribosomal protein S6 kinase 1, a downstream target of mTORC1. Consistent with these findings, selective deletion of SAD-A in pancreas decreased islet β-cell size, whereas SAD-A overexpression significantly increased the size of mouse insulinomas cell lines β-cells. In direct support of SAD-A as a unique mediator of mTORC1 signaling in islet β-cells, we demonstrate that glucose dramatically stimulated SAD-A protein translation in isolated mouse islets, which was potently inhibited by rapamycin, an inhibitor of mTORC1. Moreover, the 5'-untranslated region of SAD-A mRNA is highly structured and requires mTORC1 signaling for its translation initiation. Together, these findings identified SAD-A as a unique pancreas-specific effector protein of mTORC1 signaling.

  15. Potential differentiation of islet-like cells from pregnant cow-derived placental stem cells.

    Science.gov (United States)

    Peng, Shao-Yu; Chou, Chien-Wen; Kuo, Yu-Hsuan; Shen, Perng-Chih; Shaw, S W Steven

    2017-06-01

    Type 1 diabetes is an autoimmune disease that destroys islet cells and results in insufficient insulin secretion by pancreatic β-cells. Islet transplantation from donors is an approach used for treating patients with diabetes; however, this therapy is difficult to implement because of the lack of donors. Nevertheless, several stem cells have the potential to differentiate from islet-like cells and enable insulin secretion for treating diabetes in animal models. For example, placenta is considered a waste material and can be harvested noninvasively during delivery without ethical or moral concerns. To date, the differentiation of islet-like cells from cow-derived placental stem cells (CPSCs) has yet to be demonstrated. The investigation of potential differentiation of islet-like cells from CPSCs was conducted by supplementation with nicotinamide, exendin-4, glucose, and poly-d-lysine and was detected through reverse transcription polymerase chain reaction, dithizone staining, and immunocytochemical methods. Our results indicated that CPSCs are established and express mesenchymal stem cell surface antigen markers, such as CD73, CD166, β-integrin, and Oct-4, but not hematopoietic stem cell surface antigen markers, such as CD45. After induction, the CPSCs successfully differentiated into islet-like cells. The CPSC-derived islet-like cells expressed islet cell development-related genes, such as insulin, glucagon, pax-4, Nkx6.1, pax-6, and Fox. Moreover, CPSC-derived islet-like cells can be stained with zinc ions, which are widely distributed in the islet cells and enable insulin secretion. Altogether, islet-like cells have the potential to be differentiated from CPSCs without gene manipulation, and can be used in diabetic animal models in the future for preclinical and drug testing trial investigations. Copyright © 2017. Published by Elsevier B.V.

  16. Human interleukin 1. beta. stimulates islet insulin release by a mechanism not dependent on changes in phospholipase C and protein kinase C activities or Ca sup 2+ handling

    Energy Technology Data Exchange (ETDEWEB)

    Welsh, N.; Nilsson, T.; Hallberg, A.; Arkhammar, P.; Berggren, P.-O.; Sandler, S.

    1989-01-01

    Isolated islets from adult rats or obese hyperglycemic (ob/ob) mice were incubated with human recombinant interleukin 1{beta} in order to study whether the acute effects of the cytokine on islet insulin release are associated with changes in islet phospholipase C activity, Ca{sup 2+} handling or protein phosphorylation. The cytokine stimulated insulin release both at low and high glucose concentrations during one hour incubations. In shortterm incubations (<1 min) interleukin 1{beta} did not affect the production of inositoltrisphosphate. Addition of interleukin 1{beta} affected neither the cytoplasmic free Ca{sup 2+} concentration at rest nor that observed subsequent to stimulation with a high concentration of glucose. Furthermore, the endogenous protein kinase C activity, as visualized by immunoprecipitation of a {sup 32}P-labelled substrate for this enzyme, was not altered by interleukin 1{beta}. Separation of {sup 32}P-labelled proteins by means of 2-dimensional gel electrophoresis failed to reveal any specific effects of the cytokine on the total protein phosphorylation activity. These results suggest that the stimulatory effects on insulin release exerted by interleukin 1{beta} are not caused by acute activation of phospholipase C and protein kinase C or by an alternation of islet Ca{sup 2+} handling of the B-cells. (author).

  17. Mechanisms of pancreatic islet cell destruction. Dose-dependent cytotoxic effect of soluble blood mononuclear cell mediators on isolated islets of Langerhans

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Bendtzen, K; Nerup, J

    1986-01-01

    Supernatants of peripheral blood mononuclear cells from healthy human donors stimulated with recall antigen (purified protein derivative of tuberculin) or lectin (phytohaemagglutinin) markedly inhibited the insulin release from isolated human and rat islets of Langerhans, and decreased rat islet...... reconstituted with tuberculin or phytohaemagglutinin did not impair islet function. Electron microscopy demonstrated that supernatants were cytotoxic to islet cells. The cytotoxic mononuclear cell mediator(s) was non-dialysable, sensitive to heating to 56 degrees C, labile even when stored at -70 degrees C...

  18. Decreased insulin secretory response of pancreatic islets during culture in the presence of low glucose is associated with diminished 45Ca2+ net uptake, NADPH/NADP+ and GSH/GSSG ratios

    International Nuclear Information System (INIS)

    Verspohl, E.J.; Kaiser, P.; Wahl, M.; Ammon, H.P.T.

    1988-01-01

    In isolated rat pancreatic islets maintained at a physiologic glucose concentration (5.6 mM) the effect of glucose on parameters which are known to be involved in the insulin secretion coupling such as NADPH, reduced glutathione (GSH), 86 Rb + efflux, and 45 Ca ++ net uptake were investigated. The insulinotropic effect of 16.7 mM glucose was decreased with the period of culturing during the first 14 days being significant after 2 days though in control experiments both protein content and ATP levels per islet were not affected and insulin content was only slightly decreased. Both NADPH and GSH decreased with time of culture. 86 Rb + efflux which is decreased by enhancing the glucose concentration from 3 to 5.6 mM in freshly isolated islets was not affected by culturing whatsoever, even not after 14 days of culture when there was not longer any insulin responsiveness to glucose. The 45 Ca ++ net uptake was decreased during culturing. The data indicate (1) that the diminished glucose-stimulated release of insulin during culturing is not due to cell loss or simple energy disturbances, (2) that more likely it is the result of a diminished 45 Ca ++ net uptake as a consequence of the inability of islet cells to maintain proper NADPH and GSH levels, and (3) that potassium ( 86 Rb + ) efflux may not be related to changes of NADPH and GSH

  19. Ultraviolet light immunomodulation of canine islets for prolongation of allograft survival

    International Nuclear Information System (INIS)

    Kenyon, N.S.; Strasser, S.; Alejandro, R.

    1990-01-01

    Ultraviolet (UV) light treatment of donor islets has been shown to be effective for the prolongation of islet allograft survival in rodent models. This study evaluated UV as an immunomodulator of canine islets. The effects of UV irradiation on islet secretory function in vitro revealed a trend of increasing basal insulin release with increasing doses of UV and a corresponding significant decrease in glucose-mediated insulin release (expressed as percentage of basal fractional insulin release) beginning at UV light exposures of 200-300 J/m2 (n = 3, P less than 0.05). Proliferative responses to UV-irradiated allogeneic peripheral blood leukocytes and islets were significantly decreased by 53-112% (P less than 0.05) in 27 of 29 mixed-lymphocyte cultures and by 35-74% (P less than 0.05) in 4 of 5 mixed-lymphocyte islet culture experiments, respectively, beginning at 200-600 J/m2. Autotransplantation of nonirradiated (n = 8) and irradiated islets (600 J/m2, n = 6) resulted in a 1-mo graft survival rate of 75% for the control group and 50% for the irradiated group. Allotransplantation of irradiated islets (600 J/m2) into either nonimmunosuppressed recipients (1 donor to 1 recipient, n = 8) or recipients of subimmunosuppressive doses of cyclosporin (2 donors to 1 recipient, n = 4) resulted in 100% rejection by day 10. In contrast, when islets were cultured for 24 h postirradiation and transplanted into cyclosporin-treated pancreatectomized recipients (2 donors to 1 recipient), 3 of 7 grafts were prolonged beyond day 10 to days 16, 26, and greater than 100

  20. Closing in on the Mechanisms of Pulsatile Insulin Secretion.

    Science.gov (United States)

    Bertram, Richard; Satin, Leslie S; Sherman, Arthur S

    2018-03-01

    Insulin secretion from pancreatic islet β-cells occurs in a pulsatile fashion, with a typical period of ∼5 min. The basis of this pulsatility in mouse islets has been investigated for more than four decades, and the various theories have been described as either qualitative or mathematical models. In many cases the models differ in their mechanisms for rhythmogenesis, as well as other less important details. In this Perspective, we describe two main classes of models: those in which oscillations in the intracellular Ca 2+ concentration drive oscillations in metabolism, and those in which intrinsic metabolic oscillations drive oscillations in Ca 2+ concentration and electrical activity. We then discuss nine canonical experimental findings that provide key insights into the mechanism of islet oscillations and list the models that can account for each finding. Finally, we describe a new model that integrates features from multiple earlier models and is thus called the Integrated Oscillator Model. In this model, intracellular Ca 2+ acts on the glycolytic pathway in the generation of oscillations, and it is thus a hybrid of the two main classes of models. It alone among models proposed to date can explain all nine key experimental findings, and it serves as a good starting point for future studies of pulsatile insulin secretion from human islets. © 2018 by the American Diabetes Association.

  1. Downregulation of lncRNA TUG1 Affects Apoptosis and Insulin Secretion in Mouse Pancreatic β Cells

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    Dan-dan Yin

    2015-03-01

    Full Text Available Background: Increasing evidence indicates that long noncoding RNAs (IncRNAs perform specific biological functions in diverse processes. Recent studies have reported that IncRNAs may be involved in β cell function. The aim of this study was to characterize the role of IncRNA TUG1 in mouse pancreatic β cell functioning both in vitro and in vivo. Methods: qRT-PCR analyses were performed to detect the expression of lncRNA TUG1 in different tissues. RNAi, MTT, TUNEL and Annexin V-FITC assays and western blot, GSIS, ELISA and immunochemistry analyses were performed to detect the effect of lncRNA TUG1 on cell apoptosis and insulin secretion in vitro and in vivo. Results: lncRNA TUG1 was highly expressed in pancreatic tissue compared with other organ tissues, and expression was dynamically regulated by glucose in Nit-1 cells. Knockdown of lncRNA TUG1 expression resulted in an increased apoptosis ratio and decreased insulin secretion in β cells both in vitro and in vivo . Immunochemistry analyses suggested decreased relative islet area after treatment with lncRNA TUG1 siRNA. Conclusion: Downregulation of lncRNA TUG1 expression affected apoptosis and insulin secretion in pancreatic β cells in vitro and in vivo. lncRNA TUG1 may represent a factor that regulates the function of pancreatic β cells.

  2. Downregulation of lncRNA TUG1 affects apoptosis and insulin secretion in mouse pancreatic β cells.

    Science.gov (United States)

    Yin, Dan-dan; Zhang, Er-bao; You, Liang-hui; Wang, Ning; Wang, Lin-tao; Jin, Fei-yan; Zhu, Ya-nan; Cao, Li-hua; Yuan, Qing-xin; De, Wei; Tang, Wei

    2015-01-01

    Increasing evidence indicates that long noncoding RNAs (IncRNAs) perform specific biological functions in diverse processes. Recent studies have reported that IncRNAs may be involved in β cell function. The aim of this study was to characterize the role of IncRNA TUG1 in mouse pancreatic β cell functioning both in vitro and in vivo. qRT-PCR analyses were performed to detect the expression of lncRNA TUG1 in different tissues. RNAi, MTT, TUNEL and Annexin V-FITC assays and western blot, GSIS, ELISA and immunochemistry analyses were performed to detect the effect of lncRNA TUG1 on cell apoptosis and insulin secretion in vitro and in vivo. lncRNA TUG1 was highly expressed in pancreatic tissue compared with other organ tissues, and expression was dynamically regulated by glucose in Nit-1 cells. Knockdown of lncRNA TUG1 expression resulted in an increased apoptosis ratio and decreased insulin secretion in β cells both in vitro and in vivo . Immunochemistry analyses suggested decreased relative islet area after treatment with lncRNA TUG1 siRNA. Downregulation of lncRNA TUG1 expression affected apoptosis and insulin secretion in pancreatic β cells in vitro and in vivo. lncRNA TUG1 may represent a factor that regulates the function of pancreatic β cells. © 2015 S. Karger AG, Basel.

  3. Biotin increases glucokinase expression via soluble guanylate cyclase/protein kinase G, adenosine triphosphate production and autocrine action of insulin in pancreatic rat islets.

    Science.gov (United States)

    Vilches-Flores, Alonso; Tovar, Armando R; Marin-Hernandez, Alvaro; Rojas-Ochoa, Alberto; Fernandez-Mejia, Cristina

    2010-07-01

    Besides its role as a carboxylase prosthetic group, biotin has important effects on gene expression. However, the molecular mechanisms through which biotin exerts these effects are largely unknown. We previously found that biotin increases pancreatic glucokinase expression. We have now explored the mechanisms underlying this effect. Pancreatic islets from Wistar rats were treated with biotin, in the presence or absence of different types of inhibitors. Glucokinase mRNA and 18s rRNA abundance were determined by real-time PCR. Adenosine triphosphate (ATP) content was analyzed by fluorometry. Biotin treatment increased glucokinase mRNA abundance approximately one fold after 2 h; the effect was sustained up to 24 h. Inhibition of soluble guanylate cyclase or protein kinase G (PKG) signalling suppressed biotin-induced glucokinase expression. The cascade of events downstream of PKG in biotin-mediated gene transcription is not known. We found that inhibition of insulin secretion with diazoxide or nifedipine prevented biotin-stimulated glucokinase mRNA increase. Biotin treatment increased islet ATP content (control: 4.68+/-0.28; biotin treated: 6.62+/-0.26 pmol/islet) at 30 min. Inhibition of PKG activity suppressed the effects of biotin on ATP content. Insulin antibodies or inhibitors of phosphoinositol-3-kinase/Akt insulin signalling pathway prevented biotin-induced glucokinase expression. The nucleotide 8-Br-cGMP mimicked the biotin effects. We propose that the induction of pancreatic glucokinase mRNA by biotin involves guanylate cyclase and PKG activation, which leads to an increase in ATP content. This induces insulin secretion via ATP-sensitive potassium channels. Autocrine insulin, in turn, activates phosphoinositol-3-kinase/Akt signalling. Our results offer new insights into the pathways that participate in biotin-mediated gene expression. (c) 2010 Elsevier Inc. All rights reserved.

  4. Islet transplantation in diabetic rats normalizes basal and exercise-induced energy metabolism

    NARCIS (Netherlands)

    Houwing, Harmina; Benthem, L.; Suylichem, P.T.R. van; Leest, J. van der; Strubbe, J.H.; Steffens, A.B.

    Transplantation of islets of Langerhans in diabetic rats normalizes resting glucose and insulin levels, but it remains unclear whether islet transplantation restores resting and exercise-induced energy metabolism. Therefore, we compared energy metabolism in islet transplanted rats with energy

  5. Single-donor islet transplantation in type 1 diabetes: patient selection and special considerations

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    Tatum JA

    2017-02-01

    Full Text Available Jacob A Tatum,* Max O Meneveau,* Kenneth L Brayman Department of Surgery, Division of Transplantation, The University of Virginia Health System, Charlottesville, VA, USA *These authors contributed equally to this work. Abstract: Type 1 diabetes mellitus is an autoimmune disorder of the endocrine pancreas that currently affects millions of people in the United States. Although the disease can be managed with exogenous insulin administration, the ultimate cure for the condition lies in restoring a patient’s ability to produce their own insulin. Islet cell allotransplantation provides a means of endogenous insulin production. Though far from perfected, islet transplants are now a proven treatment for type 1 diabetics. However, proper patient selection is critical for achieving optimal outcomes. Given the shortage of transplantable organs, selecting appropriate candidates for whom the procedure will be of greatest benefit is essential. Although many of those who receive islets do not retain insulin independence, grafts do play a significant role in preventing hypoglycemic episodes that can be quite detrimental to quality of life and potentially fatal. Additionally, islet transplant requires lifelong immunosuppression. Antibodies, both preformed and following islet infusion, may play important roles in graft outcomes. Finally, no procedure is without inherent risk and islet transfusions can have serious consequences for recipients’ livers in the form of both vascular and metabolic complications. Therefore, patient-specific factors that should be taken into account before islet transplantation include aims of therapy, sensitization, and potential increased risk for hepatic and portal-venous sequelae. Keywords: islet transplantation, diabetes mellitus type 1, brittle diabetes, single donor, patient

  6. Photochemical (PUVA) treatment of isolated rat islets

    International Nuclear Information System (INIS)

    Schmidt, S.; Wilke, B.; Kloeting, I.

    1984-01-01

    Isolated rat islets were irradiated with long-wave ultraviolet light alone or in combination with the photosensitizer 8-methoxypsoralen. The influence on specific beta cell functions was determined with the aim to find out experimental conditions which allow the use of such islets for transplantation. Short-term effects: Ultraviolet light affected [ 3 H]leucine incorporation into (pro)insulin (5 J/cm 2 : 53.8 %, 10 J/cm 2 : 41.0 % of the controls) and insulin release was slightly reduced. 8-methoxypsoralen enhanced the irradiation effect. Long-term effects: A restoration of irradiation-affected beta cell function was detected after 5 days of culture unless the dose exceeded 2 J/cm 2 (0.1 μM 8-methoxypsoralen) or 1 J/cm 2 (1 μM 8-methoxypsoralen). After functional restoration islets were used for transplantation experiments. (author)

  7. Photochemical (PUVA) treatment of isolated rat islets

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, S; Wilke, B; Kloeting, I [Zentralinstitut fuer Diabetes, Karlsburg (German Democratic Republic)

    1984-05-01

    Isolated rat islets were irradiated with long-wave ultraviolet light alone or in combination with the photosensitizer 8-methoxypsoralen. The influence on specific beta cell functions was determined with the aim to find out experimental conditions which allow the use of such islets for transplantation. Short-term effects: Ultraviolet light affected (/sup 3/H)leucine incorporation into (pro)insulin (5 J/cm/sup 2/ : 53.8 %, 10 J/cm/sup 2/ : 41.0 % of the controls) and insulin release was slightly reduced. 8-methoxypsoralen enhanced the irradiation effect. Long-term effects: A restoration of irradiation-affected beta cell function was detected after 5 days of culture unless the dose exceeded 2 J/cm/sup 2/ (0.1 ..mu..M 8-methoxypsoralen) or 1 J/cm/sup 2/ (1 ..mu..M 8-methoxypsoralen). After functional restoration islets were used for transplantation experiments.

  8. Retention of gene expression in porcine islets after agarose encapsulation and long-term culture

    International Nuclear Information System (INIS)

    Dumpala, Pradeep R.; Holdcraft, Robert W.; Martis, Prithy C.; Laramore, Melissa A.; Parker, Thomas S.; Levine, Daniel M.; Smith, Barry H.; Gazda, Lawrence S.

    2016-01-01

    Agarose encapsulation of porcine islets allows extended in vitro culture, providing ample time to determine the functional capacity of the islets and conduct comprehensive microbiological safety testing prior to implantation as a treatment for type 1 diabetes mellitus. However, the effect that agarose encapsulation and long-term culture may have on porcine islet gene expression is unknown. The aim of the present study was to compare the transcriptome of encapsulated porcine islets following long-term in vitro culture against free islets cultured overnight. Global gene expression analysis revealed no significant change in the expression of 98.47% of genes. This indicates that the gene expression profile of free islets is highly conserved following encapsulation and long-term culture. Importantly, the expression levels of genes that code for critical hormones secreted by islets (insulin, glucagon, and somatostatin) as well as transcripts encoding proteins involved in their packaging and secretion are unchanged. While a small number of genes known to play roles in the insulin secretion and insulin signaling pathways are differentially expressed, our results show that overall gene expression is retained following islet isolation, agarose encapsulation, and long-term culture. - Highlights: • Effect of agarose encapsulation and 8 week culture on porcine islets was analyzed. • Transcriptome analysis revealed no significant change in a majority (98%) of genes. • Agarose encapsulation allows for long-term culture of porcine islets. • Islet culture allows for functional and microbial testing prior to clinical use.

  9. Retention of gene expression in porcine islets after agarose encapsulation and long-term culture

    Energy Technology Data Exchange (ETDEWEB)

    Dumpala, Pradeep R., E-mail: pdumpala@rixd.org [The Rogosin Institute – Xenia Division, 740 Birch Road, Xenia, OH 45385 (United States); Holdcraft, Robert W.; Martis, Prithy C.; Laramore, Melissa A. [The Rogosin Institute – Xenia Division, 740 Birch Road, Xenia, OH 45385 (United States); Parker, Thomas S.; Levine, Daniel M. [The Rogosin Institute, 505 East 70th Street, New York, NY 10021 (United States); Smith, Barry H. [The Rogosin Institute, 505 East 70th Street, New York, NY 10021 (United States); NewYork-Presbyterian Hospital, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021 (United States); Gazda, Lawrence S. [The Rogosin Institute – Xenia Division, 740 Birch Road, Xenia, OH 45385 (United States)

    2016-08-05

    Agarose encapsulation of porcine islets allows extended in vitro culture, providing ample time to determine the functional capacity of the islets and conduct comprehensive microbiological safety testing prior to implantation as a treatment for type 1 diabetes mellitus. However, the effect that agarose encapsulation and long-term culture may have on porcine islet gene expression is unknown. The aim of the present study was to compare the transcriptome of encapsulated porcine islets following long-term in vitro culture against free islets cultured overnight. Global gene expression analysis revealed no significant change in the expression of 98.47% of genes. This indicates that the gene expression profile of free islets is highly conserved following encapsulation and long-term culture. Importantly, the expression levels of genes that code for critical hormones secreted by islets (insulin, glucagon, and somatostatin) as well as transcripts encoding proteins involved in their packaging and secretion are unchanged. While a small number of genes known to play roles in the insulin secretion and insulin signaling pathways are differentially expressed, our results show that overall gene expression is retained following islet isolation, agarose encapsulation, and long-term culture. - Highlights: • Effect of agarose encapsulation and 8 week culture on porcine islets was analyzed. • Transcriptome analysis revealed no significant change in a majority (98%) of genes. • Agarose encapsulation allows for long-term culture of porcine islets. • Islet culture allows for functional and microbial testing prior to clinical use.

  10. Islet Assessment for Transplantation

    Science.gov (United States)

    Papas, Klearchos K.; Suszynski, Thomas M.; Colton, Clark. K.

    2010-01-01

    Purpose of review There is a critical need for meaningful viability and potency assays that characterize islet preparations for release prior to clinical islet cell transplantation (ICT). Development, testing, and validation of such assays have been the subject of intense investigation for the past decade. These efforts are reviewed, highlighting the most recent results while focusing on the most promising assays. Recent Findings Assays based on membrane integrity do not reflect true viability when applied to either intact islets or dispersed islet cells. Assays requiring disaggregation of intact islets into individual cells for assessment introduce additional problems of cell damage and loss. Assays evaluating mitochondrial function, specifically mitochondrial membrane potential, bioenergetic status, and cellular oxygen consumption rate (OCR), especially when conducted with intact islets, appear most promising in evaluating their quality prior to ICT. Prospective, quantitative assays based on measurements of OCR with intact islets have been developed, validated and their results correlated with transplant outcomes in the diabetic nude mouse bioassay. Conclusion More sensitive and reliable islet viability and potency tests have been recently developed and tested. Those evaluating mitochondrial function are most promising, correlate with transplant outcomes in mice, and are currently being evaluated in the clinical setting. PMID:19812494

  11. Increased insulin sensitivity and changes in the expression profile of key insulin regulatory genes and beta cell transcription factors in diabetic KKAy-mice after feeding with a soy bean protein rich diet high in isoflavone content.

    Science.gov (United States)

    Nordentoft, I; Jeppesen, P B; Hong, J; Abudula, R; Hermansen, K

    2008-06-25

    High content isoflavone soy protein (SBP) (Abalon) has been found in animal studies to possess beneficial effects on a number of the characteristic features of the insulin resistance syndrome. The aim of this study was to investigate whether SBP exerts beneficial effects on metabolism in the diabetic KKAy-mouse. Furthermore, we investigated the long-term in vivo effect of SBP on the expression profile in islets of key insulin regulatory genes. Twenty KKAy-mice, aged 5 weeks, were divided into 2 groups and treated for 9 weeks with either (A) standard chow diet (control) or (B) chow + 50% SBP. Twenty normal C57BL-mice fed with standard chow diet served as nondiabetic controls (C). Blood samples were collected and analyzed before and after intervention. Gene expression was determined in islets by quantitative real-time RT-PCR and Affymetrix microarray. It was demonstrated that long-term treatment with SBP improves glucose homeostasis, increases insulin sensitivity, and lowers plasma triglycerides in diabetic KKAy-mice. SBP reduces fasting plasma glucose, insulin, triglycerides, and total cholesterol. Furthermore, SBP markedly changes the gene expression profile of key insulin regulatory genes GLUT2, GLUT3, Ins1, Ins2, IGF1, Beta2/Neurod1, cholecystokinin, and LDLr, and proliferative genes in islets isolated from KKAy-mice. After 9 weeks of treatment with SBP, plasma glucose and insulin homeostasis was normalized compared to start levels. The results indicate that SBP improves glucose and insulin sensitivity and up-regulates the expression of key insulin regulatory genes.

  12. Serum Cytokines as Biomarkers in Islet Cell Transplantation for Type 1 Diabetes

    NARCIS (Netherlands)

    van der Torren, Cornelis R; Verrijn Stuart, Annemarie A; Lee, DaHae; Meerding, Jenny; van de Velde, Ursule; Pipeleers, Daniel; Gillard, Pieter; Keymeulen, Bart; de Jager, Wilco; Roep, Bart O

    2016-01-01

    BACKGROUND: Islet cell transplantation holds a potential cure for type 1 diabetes, but many islet recipients do not reach long-lasting insulin independence. In this exploratory study, we investigated whether serum cytokines, chemokines and adipokines are associated with the clinical outcome of islet

  13. Encapsulation of pancreatic islets for transplantation in diabetes : the untouchable islets

    NARCIS (Netherlands)

    de Vos, P; Marchetti, P

    The aim of encapsulation of pancreatic islets is to transplant in the absence of immunosuppression. It is based on the principle that transplanted tissue is protected from the host immune system by an artificial membrane. Encapsulation allows for application of insulin-secreting cells of animal or

  14. Protein-Mediated Interactions of Pancreatic Islet Cells

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    Paolo Meda

    2013-01-01

    Full Text Available The islets of Langerhans collectively form the endocrine pancreas, the organ that is soley responsible for insulin secretion in mammals, and which plays a prominent role in the control of circulating glucose and metabolism. Normal function of these islets implies the coordination of different types of endocrine cells, noticeably of the beta cells which produce insulin. Given that an appropriate secretion of this hormone is vital to the organism, a number of mechanisms have been selected during evolution, which now converge to coordinate beta cell functions. Among these, several mechanisms depend on different families of integral membrane proteins, which ensure direct (cadherins, N-CAM, occludin, and claudins and paracrine communications (pannexins between beta cells, and between these cells and the other islet cell types. Also, other proteins (integrins provide communication of the different islet cell types with the materials that form the islet basal laminae and extracellular matrix. Here, we review what is known about these proteins and their signaling in pancreatic β-cells, with particular emphasis on the signaling provided by Cx36, given that this is the integral membrane protein involved in cell-to-cell communication, which has so far been mostly investigated for effects on beta cell functions.

  15. Vitality of pancreatic islets labeled for magnetic resonance imaging with iron particles.

    Science.gov (United States)

    Berkova, Z; Kriz, J; Girman, P; Zacharovova, K; Koblas, T; Dovolilova, E; Saudek, F

    2005-10-01

    We previously described an in vivo method for pancreatic islet visualization using magnetic resonance imaging with the aid of superparamagnetic nanoparticles of iron oxide (Resovist) or by magnetic beads precoated with antibodies (Dynabeads). The aim of this study was to investigate the in vitro effect of islet labeling on their quality. Isolated rat islets were cultivated for 48 hours with a contrast agent or, in the case of magnetic antibody-coated beads, for only 2 hours. The ability to secrete insulin was tested by a static insulin release assay and the results were expressed as a stimulation index. Staining with propidium iodide and acridine orange was performed to determine the ratio of live to dead cells. Stimulation indices in the Resovist islets (n = 23) vs controls (n = 14) were 15.3 and 15.0, respectively, and in the Dynabeads islets (n = 15) vs controls (n = 12) 21.3 and 19.9, respectively. The vitality of the Resovist islets vs controls determined by live/dead cells ratio was 90.8% and 91.1%, respectively (n = 20), and in the Dynabeads islets vs controls was 89.4% and 91.8%, respectively (n = 11). Islet labeling with the contrast agent as well as with specific antibodies with iron beads did not change the vitality and insulin-secreting capacity assessed in vitro (P > .05). Magnetic resonance using iron nanoparticles represents the only method for in-vivo visualization of transplanted islets so far. Our data represent an important contribution for its clinical use.

  16. Altered pancreatic growth and insulin secretion in WSB/EiJ mice.

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    Maggie M Ho

    Full Text Available These data suggest that insulin secretion in WSB mice is blunted specifically in vivo, either due to a reduced insulin requirement and/or due to factors that are absent or destroyed in vitro. These studies also highlight the role of post-natal growth in determining adult β-cell mass. Mice are important animal models for the study of metabolic physiology and the genetics of complex traits. Wild-derived inbred mouse strains, such as WSB/EiJ (WSB, are unrelated to the commonly studied mouse strains and are valuable tools to identify novel genes that modify disease risk. We have previously shown that in contrast to C57BL/6J (B6 mice, WSB mice fed a high fat diet do not develop hyperinsulinemia or insulin resistance, and had nearly undetectable insulin secretion in response to an intraperitoneal glucose challenge. As hyperinsulinemia may drive obesity and insulin resistance, we examined whether defects in β-cell mass or function could contribute to the low insulin levels in WSB mice. In young WSB mice, β-cell mass was similar to B6 mice. However, we found that adult WSB mice had reduced β-cell mass due to reduced pancreatic weights. Pancreatic sizes were similar between the strains when normalized to body weight, suggesting their pancreatic size is appropriate to their body size in adults, but overall post-natal pancreatic growth was reduced in WSB mice compared to B6 mice. Islet architecture was normal in WSB mice. WSB mice had markedly increased insulin secretion from isolated islets in vitro. These data suggest that insulin secretion in WSB mice is blunted specifically in vivo, either due to a reduced insulin requirement and/or due to factors that are absent or destroyed in vitro. These studies suggest that WSB mice may provide novel insight into mechanisms regulating insulin secretion and also highlight the role of post-natal growth in determining adult β-cell mass.

  17. Increased expression of SNARE proteins and synaptotagmin IV in islets from pregnant rats and in vitro prolactin-treated neonatal islets

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    DANIEL A CUNHA

    2006-01-01

    Full Text Available During pregnancy and the perinatal period of life, prolactin (PRL and other lactogenic substances induce adaptation and maturation of the stimulus-secretion coupling system in pancreatic β-cells. Since the SNARE molecules, SNAP-25, syntaxin 1, VAMP-2, and synaptotagmins participate in insulin secretion, we investigated whether the improved secretory response to glucose during these periods involves alteration in the expression of these proteins. mRNA was extracted from neonatal rat islets cultured for 5 days in the presence of PRL and from pregnant rats (17th-18th days of pregnancy and reverse transcribed. The expression of genes was analyzed by semi-quantitative RT-PCR assay. The expression of proteins was analyzed by Western blotting and confocal microscopy. Transcription and expression of all SNARE genes and proteins were increased in islets from pregnant and PRL-treated neonatal rats when compared with controls. The only exception was VAMP-2 production in islets from pregnant rats. Increased mRNA and protein expression of synaptotagmin IV, but not the isoform I, also was observed in islets from pregnant and PRL-treated rats. This effect was not inhibited by wortmannin or PD098059, inhibitors of the PI3-kinase and MAPK pathways, respectively. As revealed by confocal laser microscopy, both syntaxin 1A and synaptotagmin IV were immunolocated in islet cells, including the insulin-containing cells. These results indicate that PRL modulates the final steps of insulin secretion by increasing the expression of proteins involved in membrane fusion.

  18. Extracellular Matrix and Growth Factors Improve the Efficacy of Intramuscular Islet Transplantation.

    Science.gov (United States)

    Tsuchiya, Haruyuki; Sakata, Naoaki; Yoshimatsu, Gumpei; Fukase, Masahiko; Aoki, Takeshi; Ishida, Masaharu; Katayose, Yu; Egawa, Shinichi; Unno, Michiaki

    2015-01-01

    The efficacy of intramuscular islet transplantation is poor despite being technically simple, safe, and associated with reduced rates of severe complications. We evaluated the efficacy of combined treatment with extracellular matrix (ECM) and growth factors in intramuscular islet transplantation. Male BALB/C mice were used for the in vitro and transplantation studies. The following three groups were evaluated: islets without treatment (islets-only group), islets embedded in ECM with growth factors (Matrigel group), and islets embedded in ECM without growth factors [growth factor-reduced (GFR) Matrigel group]. The viability and insulin-releasing function of islets cultured for 96 h were significantly improved in Matrigel and GFR Matrigel groups compared with the islets-only group. Blood glucose and serum insulin levels immediately following transplantation were significantly improved in the Matrigel and GFR Matrigel groups and remained significantly improved in the Matrigel group at postoperative day (POD) 28. On histological examination, significantly decreased numbers of TdT-mediated deoxyuridine triphosphate-biotin nick end labeling-positive islet cells and significantly increased numbers of Ki67-positive cells were observed in the Matrigel and GFR Matrigel groups at POD 3. Peri-islet revascularization was most prominent in the Matrigel group at POD 14. The efficacy of intramuscular islet transplantation was improved by combination treatment with ECM and growth factors through the inhibition of apoptosis, increased proliferation of islet cells, and promotion of revascularization.

  19. Essential role of the small GTPase Ran in postnatal pancreatic islet development.

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    Fang Xia

    Full Text Available The small GTPase Ran orchestrates pleiotropic cellular responses of nucleo-cytoplasmic shuttling, mitosis and subcellular trafficking, but whether deregulation of these pathways contributes to disease pathogenesis has remained elusive. Here, we generated transgenic mice expressing wild type (WT Ran, loss-of-function Ran T24N mutant or constitutively active Ran G19V mutant in pancreatic islet β cells under the control of the rat insulin promoter. Embryonic pancreas and islet development, including emergence of insulin(+ β cells, was indistinguishable in control or transgenic mice. However, by one month after birth, transgenic mice expressing any of the three Ran variants exhibited overt diabetes, with hyperglycemia, reduced insulin production, and nearly complete loss of islet number and islet mass, in vivo. Deregulated Ran signaling in transgenic mice, adenoviral over-expression of WT or mutant Ran in isolated islets, or short hairpin RNA (shRNA silencing of endogenous Ran in model insulinoma INS-1 cells, all resulted in decreased expression of the pancreatic and duodenal homeobox transcription factor, PDX-1, and reduced β cell proliferation, in vivo. These data demonstrate that a finely-tuned balance of Ran GTPase signaling is essential for postnatal pancreatic islet development and glucose homeostasis, in vivo.

  20. Dual role of interleukin-1β in islet amyloid formation and its β-cell toxicity: Implications for type 2 diabetes and islet transplantation.

    Science.gov (United States)

    Park, Yoo Jin; Warnock, Garth L; Ao, Ziliang; Safikhan, Nooshin; Meloche, Mark; Asadi, Ali; Kieffer, Timothy J; Marzban, Lucy

    2017-05-01

    Islet amyloid, formed by aggregation of human islet amyloid polypeptide (hIAPP), contributes to β-cell failure in type 2 diabetes, cultured and transplanted islets. We previously showed that biosynthetic hIAPP aggregates induce β-cell Fas upregulation and activation of the Fas apoptotic pathway. We used cultured human and hIAPP-expressing mouse islets to investigate: (1) the role of interleukin-1β (IL-1β) in amyloid-induced Fas upregulation; and (2) the effects of IL-1β-induced β-cell dysfunction on pro-islet amyloid polypeptide (proIAPP) processing and amyloid formation. Human and h IAPP -expressing mouse islets were cultured to form amyloid without or with the IL-1 receptor antagonist (IL-1Ra) anakinra, in the presence or absence of recombinant IL-1β. Human islets in which amyloid formation was prevented (amyloid inhibitor or Ad-prohIAPP-siRNA) were cultured similarly. β-cell function, apoptosis, Fas expression, caspase-8 activation, islet IL-1β, β-cell area, β-/α-cell ratio, amyloid formation, and (pro)IAPP forms were assessed. hIAPP aggregates were found to increase IL-1β levels in cultured human islets that correlated with β-cell Fas upregulation, caspase-8 activation and apoptosis, all of which were reduced by IL-1Ra treatment or prevention of amyloid formation. Moreover, IL-1Ra improved culture-induced β-cell dysfunction and restored impaired proIAPP processing, leading to lower amyloid formation. IL-1β treatment potentiated impaired proIAPP processing and increased amyloid formation in cultured human and h IAPP -expressing mouse islets, which were prevented by IL-1Ra. IL-1β plays a dual role by: (1) mediating amyloid-induced Fas upregulation and β-cell apoptosis; (2) inducing impaired proIAPP processing thereby potentiating amyloid formation. Blocking IL-1β may provide a new strategy to preserve β cells in conditions associated with islet amyloid formation. © 2017 John Wiley & Sons Ltd.

  1. An ancestral role for the mitochondrial pyruvate carrier in glucose-stimulated insulin secretion

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    Kyle S. McCommis

    2016-08-01

    Full Text Available Objective: Transport of pyruvate into the mitochondrial matrix by the Mitochondrial Pyruvate Carrier (MPC is an important and rate-limiting step in its metabolism. In pancreatic β-cells, mitochondrial pyruvate metabolism is thought to be important for glucose sensing and glucose-stimulated insulin secretion. Methods: To evaluate the role that the MPC plays in maintaining systemic glucose homeostasis, we used genetically-engineered Drosophila and mice with loss of MPC activity in insulin-producing cells. Results: In both species, MPC deficiency results in elevated blood sugar concentrations and glucose intolerance accompanied by impaired glucose-stimulated insulin secretion. In mouse islets, β-cell MPC-deficiency resulted in decreased respiration with glucose, ATP-sensitive potassium (KATP channel hyperactivity, and impaired insulin release. Moreover, treatment of pancreas-specific MPC knockout mice with glibenclamide, a sulfonylurea KATP channel inhibitor, improved defects in islet insulin secretion and abnormalities in glucose homeostasis in vivo. Finally, using a recently-developed biosensor for MPC activity, we show that the MPC is rapidly stimulated by glucose treatment in INS-1 insulinoma cells suggesting that glucose sensing is coupled to mitochondrial pyruvate carrier activity. Conclusions: Altogether, these studies suggest that the MPC plays an important and ancestral role in insulin-secreting cells in mediating glucose sensing, regulating insulin secretion, and controlling systemic glycemia. Keywords: Stimulus-coupled secretion, Insulin, β-Cell, Diabetes, Pyruvate, Mitochondria, Drosophila

  2. Transplantation of bone marrow derived cells promotes pancreatic islet repair in diabetic mice

    International Nuclear Information System (INIS)

    Gao Xiaodong; Song Lujun; Shen Kuntang; Wang Hongshan; Niu Weixin; Qin Xinyu

    2008-01-01

    The transplantation of bone marrow (BM) derived cells to initiate pancreatic regeneration is an attractive but as-yet unrealized strategy. Presently, BM derived cells from green fluorescent protein transgenic mice were transplanted into diabetic mice. Repair of diabetic islets was evidenced by reduction of hyperglycemia, increase in number of islets, and altered pancreatic histology. Cells in the pancreata of recipient mice co-expressed BrdU and insulin. Double staining revealed β cells were in the process of proliferation. BrdU + insulin - PDX-1 + cells, Ngn3 + cells and insulin + glucagon + cells, which showed stem cells, were also found during β-cell regeneration. The majority of transplanted cells were mobilized to the islet and ductal regions. In recipient pancreas, transplanted cells simultaneously expressed CD34 but did not express insulin, PDX-1, Ngn3, Nkx2.2, Nkx6.1, Pax4, Pax6, and CD45. It is concluded that BM derived cells especially CD34 + cells can promote repair of pancreatic islets. Moreover, both proliferation of β cells and differentiation of pancreatic stem cells contribute to the regeneration of β cells

  3. Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

    International Nuclear Information System (INIS)

    Lubaczeuski, C.; Balbo, S.L.; Ribeiro, R.A.; Vettorazzi, J.F.; Santos-Silva, J.C.; Carneiro, E.M.; Bonfleur, M.L.

    2015-01-01

    The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca 2+ mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca 2+ mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats

  4. Islet grafting and imaging in a bioengineered intramuscular space†

    Science.gov (United States)

    Witkowski, Piotr; Sondermeijer, Hugo; Hardy, Mark A.; Woodland, David C.; Lee, Keagan; Bhagat, Govind; Witkowski, Kajetan; See, Fiona; Rana, Abbas; Maffei, Antonella; Itescu, Silviu; Harris, Paul E.

    2011-01-01

    Background Since the hepatic portal system may not be the optimal site for islet transplantation, several extrahepatic sites have been studied. Here we examine an intramuscular transplantation site, bioengineered to better support islet neovascularization, engraftment, and survival, and demonstrate that at this novel site, grafted beta cell mass may be quantitated in a real time non-invasive manner by PET imaging. Methods Streptozotocin induced rats were pretreated intramuscularly with a biocompatible angiogenic scaffold received syngeneic islet transplants 2 weeks later. The recipients were monitored serially by blood glucose and glucose tolerance measurements and by PET imaging of the transplant site with [11C] dihydrotetrabenazine. Parallel histopathologic evaluation of the grafts was done using insulin staining and evaluation of microvasularity. Results Reversal of hyperglycemia by islet transplantation was most successful in recipients pretreated with bioscaffolds containing angiogenic factors as compared to those who received no bioscaffolds or bioscaffolds not treated with angiogenic factors. PET imaging with [11C] dihydrotetrabenazine, insulin staining and microvascular density patterns were consistent with islet survival, increased levels of angiogenesis, and with reversal of hyperglycemia. Conclusions Induction of increased neovascularization at an intramuscular site significantly improves islet transplant engraftment and survival compared to controls. The use of a non hepatic transplant site may avoid intrahepatic complications and permit the use of PET imaging to measure and follow transplanted beta-cell mass in real time. These findings have important implications for effective islet implantation outside of the liver, and offer promising possibilities for improving islet survival, monitoring, and even prevention of islet loss. PMID:19898201

  5. Islet grafting and imaging in a bioengineered intramuscular space.

    Science.gov (United States)

    Witkowski, Piotr; Sondermeijer, Hugo; Hardy, Mark A; Woodland, David C; Lee, Keagan; Bhagat, Govind; Witkowski, Kajetan; See, Fiona; Rana, Abbas; Maffei, Antonella; Itescu, Silviu; Harris, Paul E

    2009-11-15

    Because the hepatic portal system may not be the optimal site for islet transplantation, several extrahepatic sites have been studied. Here, we examine an intramuscular transplantation site, bioengineered to better support islet neovascularization, engraftment, and survival, and we demonstrate that at this novel site, grafted beta cell mass may be quantitated in a real-time noninvasive manner by positron emission tomography (PET) imaging. Streptozotocin-induced rats were pretreated intramuscularly with a biocompatible angiogenic scaffold received syngeneic islet transplants 2 weeks later. The recipients were monitored serially by blood glucose and glucose tolerance measurements and by PET imaging of the transplant site with [11C] dihydrotetrabenazine. Parallel histopathologic evaluation of the grafts was performed using insulin staining and evaluation of microvasularity. Reversal of hyperglycemia by islet transplantation was most successful in recipients pretreated with bioscaffolds containing angiogenic factors when compared with those who received no bioscaffolds or bioscaffolds not treated with angiogenic factors. PET imaging with [11C] dihydrotetrabenazine, insulin staining, and microvascular density patterns were consistent with islet survival, increased levels of angiogenesis, and with reversal of hyperglycemia. Induction of increased neovascularization at an intramuscular site significantly improves islet transplant engraftment and survival compared with controls. The use of a nonhepatic transplant site may avoid intrahepatic complications and permit the use of PET imaging to measure and follow transplanted beta cell mass in real time. These findings have important implications for effective islet implantation outside of the liver and offer promising possibilities for improving islet survival, monitoring, and even prevention of islet loss.

  6. The role of interventional radiology and imaging in pancreatic islet cell transplantation

    International Nuclear Information System (INIS)

    Dixon, S.; Tapping, C.R.; Walker, J.N.; Bratby, M.; Anthony, S.; Boardman, P.; Phillips-Hughes, J.; Uberoi, R.

    2012-01-01

    Pancreatic islet cell transplantation (PICT) is a novel treatment for patients with insulin-dependent diabetes who have inadequate glycaemic control or hypoglycaemic unawareness, and who suffer from the microvascular/macrovascular complications of diabetes despite aggressive medical management. Islet transplantation primarily aims to improve the quality of life for type 1 diabetic patients by achieving insulin independence, preventing hypoglycaemic episodes, and reversing hypoglycaemic unawareness. The islet cells for transplantation are extracted and purified from the pancreas of brain-stem dead, heart-beating donors. They are infused into the recipient's portal vein, where they engraft into the liver to release insulin in order to restore euglycaemia. Initial strategies using surgical access to the portal vein have been superseded by percutaneous access using interventional radiology techniques, which are relatively straightforward to perform. It is important to be vigilant during the procedure in order to prevent major complications, such as haemorrhage, which can be potentially life-threatening. In this article we review the history of islet cell transplantation, present an illustrated review of our experience with islet cell transplantation by describing the role of imaging and interventional radiology, and discuss current research into imaging techniques for monitoring graft function.

  7. Pancreas Islet Transplantation for Patients With Type 1 Diabetes Mellitus: A Clinical Evidence Review.

    Science.gov (United States)

    2015-01-01

    Type 1 diabetes mellitus is caused by the autoimmune destruction of pancreatic beta (β) cells, resulting in severe insulin deficiency. Islet transplantation is a β-cell replacement therapeutic option that aims to restore glycemic control in patients with type 1 diabetes. The objective of this study was to determine the clinical effectiveness of islet transplantation in patients with type 1 diabetes, with or without kidney disease. We conducted a systematic review of the literature on islet transplantation for type 1 diabetes, including relevant health technology assessments, systematic reviews, meta-analyses, and observational studies. We used a two-step process: first, we searched for systematic reviews and health technology assessments; second, we searched primary studies to update the chosen health technology assessment. The Assessment of Multiple Systematic Reviews measurement tool was used to examine the methodological quality of the systematic reviews and health technology assessments. We assessed the quality of the body of evidence and the risk of bias according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. Our searched yielded 1,354 citations. One health technology assessment, 11 additional observational studies to update the health technology assessment, one registry report, and four guidelines were included; the observational studies examined islet transplantation alone, islet-after-kidney transplantation, and simultaneous islet-kidney transplantation. In general, low to very low quality of evidence exists for islet transplantation in patients with type 1 diabetes with difficult-to-control blood glucose levels, with or without kidney disease, for these outcomes: health-related quality of life, secondary complications of diabetes, glycemic control, and adverse events. However, high quality of evidence exists for the specific glycemic control outcome of insulin independence compared with

  8. Phase transitions in pancreatic islet cellular networks and implications for type-1 diabetes

    Science.gov (United States)

    Stamper, I. J.; Jackson, Elais; Wang, Xujing

    2014-01-01

    In many aspects the onset of a chronic disease resembles a phase transition in a complex dynamic system: Quantitative changes accumulate largely unnoticed until a critical threshold is reached, which causes abrupt qualitative changes of the system. In this study we examine a special case, the onset of type-1 diabetes (T1D), a disease that results from loss of the insulin-producing pancreatic islet β cells. Within each islet, the β cells are electrically coupled to each other via gap-junctional channels. This intercellular coupling enables the β cells to synchronize their insulin release, thereby generating the multiscale temporal rhythms in blood insulin that are critical to maintaining blood glucose homeostasis. Using percolation theory we show how normal islet function is intrinsically linked to network connectivity. In particular, the critical amount of β-cell death at which the islet cellular network loses site percolation is consistent with laboratory and clinical observations of the threshold loss of β cells that causes islet functional failure. In addition, numerical simulations confirm that the islet cellular network needs to be percolated for β cells to synchronize. Furthermore, the interplay between site percolation and bond strength predicts the existence of a transient phase of islet functional recovery after onset of T1D and introduction of treatment, potentially explaining the honeymoon phenomenon. Based on these results, we hypothesize that the onset of T1D may be the result of a phase transition of the islet β-cell network.

  9. Extracellular Matrix and Growth Factors Improve the Efficacy of Intramuscular Islet Transplantation.

    Directory of Open Access Journals (Sweden)

    Haruyuki Tsuchiya

    Full Text Available The efficacy of intramuscular islet transplantation is poor despite being technically simple, safe, and associated with reduced rates of severe complications. We evaluated the efficacy of combined treatment with extracellular matrix (ECM and growth factors in intramuscular islet transplantation.Male BALB/C mice were used for the in vitro and transplantation studies. The following three groups were evaluated: islets without treatment (islets-only group, islets embedded in ECM with growth factors (Matrigel group, and islets embedded in ECM without growth factors [growth factor-reduced (GFR Matrigel group]. The viability and insulin-releasing function of islets cultured for 96 h were significantly improved in Matrigel and GFR Matrigel groups compared with the islets-only group.Blood glucose and serum insulin levels immediately following transplantation were significantly improved in the Matrigel and GFR Matrigel groups and remained significantly improved in the Matrigel group at postoperative day (POD 28. On histological examination, significantly decreased numbers of TdT-mediated deoxyuridine triphosphate-biotin nick end labeling-positive islet cells and significantly increased numbers of Ki67-positive cells were observed in the Matrigel and GFR Matrigel groups at POD 3. Peri-islet revascularization was most prominent in the Matrigel group at POD 14.The efficacy of intramuscular islet transplantation was improved by combination treatment with ECM and growth factors through the inhibition of apoptosis, increased proliferation of islet cells, and promotion of revascularization.

  10. NNT reverse mode of operation mediates glucose control of mitochondrial NADPH and glutathione redox state in mouse pancreatic β-cells

    Directory of Open Access Journals (Sweden)

    Laila R.B. Santos

    2017-06-01

    Full Text Available Objective: The glucose stimulation of insulin secretion (GSIS by pancreatic β-cells critically depends on increased production of metabolic coupling factors, including NADPH. Nicotinamide nucleotide transhydrogenase (NNT typically produces NADPH at the expense of NADH and ΔpH in energized mitochondria. Its spontaneous inactivation in C57BL/6J mice was previously shown to alter ATP production, Ca2+ influx, and GSIS, thereby leading to glucose intolerance. Here, we tested the role of NNT in the glucose regulation of mitochondrial NADPH and glutathione redox state and reinvestigated its role in GSIS coupling events in mouse pancreatic islets. Methods: Islets were isolated from female C57BL/6J mice (J-islets, which lack functional NNT, and genetically close C57BL/6N mice (N-islets. Wild-type mouse NNT was expressed in J-islets by adenoviral infection. Mitochondrial and cytosolic glutathione oxidation was measured with glutaredoxin 1-fused roGFP2 probes targeted or not to the mitochondrial matrix. NADPH and NADH redox state was measured biochemically. Insulin secretion and upstream coupling events were measured under dynamic or static conditions by standard procedures. Results: NNT is largely responsible for the acute glucose-induced rise in islet NADPH/NADP+ ratio and decrease in mitochondrial glutathione oxidation, with a small impact on cytosolic glutathione. However, contrary to current views on NNT in β-cells, these effects resulted from a glucose-dependent reduction in NADPH consumption by NNT reverse mode of operation, rather than from a stimulation of its forward mode of operation. Accordingly, the lack of NNT in J-islets decreased their sensitivity to exogenous H2O2 at non-stimulating glucose. Surprisingly, the lack of NNT did not alter the glucose-stimulation of Ca2+ influx and upstream mitochondrial events, but it markedly reduced both phases of GSIS by altering Ca2+-induced exocytosis and its metabolic amplification. Conclusion: These

  11. Islet cytotoxicity of interleukin 1. Influence of culture conditions and islet donor characteristics

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Spinas, G A; Prowse, S J

    1987-01-01

    We recently demonstrated that the macrophage product interleukin 1 (IL-1) is cytotoxic to isolated pancreatic islets and hypothesized that IL-1 is responsible for beta-cell destruction in insulin-dependent diabetes mellitus (IDDM). We studied whether the variation in IDDM preponderance with age, ...

  12. Reactive oxygen species as a signal in glucose-stimulated insulin secretion.

    Science.gov (United States)

    Pi, Jingbo; Bai, Yushi; Zhang, Qiang; Wong, Victoria; Floering, Lisa M; Daniel, Kiefer; Reece, Jeffrey M; Deeney, Jude T; Andersen, Melvin E; Corkey, Barbara E; Collins, Sheila

    2007-07-01

    One of the unique features of beta-cells is their relatively low expression of many antioxidant enzymes. This could render beta-cells susceptible to oxidative damage but may also provide a system that is sensitive to reactive oxygen species as signals. In isolated mouse islets and INS-1(832/13) cells, glucose increases intracellular accumulation of H2O2. In both models, insulin secretion could be stimulated by provision of either exogenous H2O2 or diethyl maleate, which raises intracellular H2O2 levels. Provision of exogenous H2O2 scavengers, including cell permeable catalase and N-acetyl-L-cysteine, inhibited glucose-stimulated H2O2 accumulation and insulin secretion (GSIS). In contrast, cell permeable superoxide dismutase, which metabolizes superoxide into H2O2, had no effect on GSIS. Because oxidative stress is an important risk factor for beta-cell dysfunction in diabetes, the relationship between glucose-induced H2O2 generation and GSIS was investigated under various oxidative stress conditions. Acute exposure of isolated mouse islets or INS-1(832/13) cells to oxidative stressors, including arsenite, 4-hydroxynonenal, and methylglyoxal, led to decreased GSIS. This impaired GSIS was associated with increases in a battery of endogenous antioxidant enzymes. Taken together, these findings suggest that H2O2 derived from glucose metabolism is one of the metabolic signals for insulin secretion, whereas oxidative stress may disturb its signaling function.

  13. Islets of Langerhans in the parakeet, Psittacula krameri.

    Science.gov (United States)

    Gupta, Y K; Kumar, S

    1980-01-01

    The pancreatic gland of Psittacula krameri is divisible into 4 lobes i.e. dorsal, ventral, third and splenic. The endocrine part is composed of alpha 1-, alpha 2- and beta-cells. The islets are of 4 kinds viz., alpha islets (having alpha 1- and alpha 2-cells), beta islets (having beta- and alpha 1-cells), pure beta islets (consisting of beta-cells exclusively) and mixed islets (with beta-, alpha 1- and alpha 2-cells). The distribution of alpha islets is mostly restricted to the splenic and third lobes whereas the beta islets are found in all 4 lobes. Though the alpha islets are only few in the dorsal lobe, their size is best developed in the third and dorsal lobes. Sometimes beta and alpha islets are present in very close proximity but their cells never mingle. An interesting feature was the complete absence of alpha islets from the ventral lobe.A relative abundance of alpha 2- cells in this bird seems to be associated with its comparatively higher blood glucose level and frugivorous habit. Tinctorial reactions suggest that the insulin content of the endocrine pancreas is low. There were no seasonal changes in the islet tissue of P. krameri.

  14. Insulin and insulin signaling play a critical role in fat induction of insulin resistance in mouse

    Science.gov (United States)

    Ning, Jie; Hong, Tao; Yang, Xuefeng; Mei, Shuang; Liu, Zhenqi; Liu, Hui-Yu

    2011-01-01

    The primary player that induces insulin resistance has not been established. Here, we studied whether or not fat can cause insulin resistance in the presence of insulin deficiency. Our results showed that high-fat diet (HFD) induced insulin resistance in C57BL/6 (B6) mice. The HFD-induced insulin resistance was prevented largely by the streptozotocin (STZ)-induced moderate insulin deficiency. The STZ-induced insulin deficiency prevented the HFD-induced ectopic fat accumulation and oxidative stress in liver and gastrocnemius. The STZ-induced insulin deficiency prevented the HFD- or insulin-induced increase in hepatic expression of long-chain acyl-CoA synthetases (ACSL), which are necessary for fatty acid activation. HFD increased mitochondrial contents of long-chain acyl-CoAs, whereas it decreased mitochondrial ADP/ATP ratio, and these HFD-induced changes were prevented by the STZ-induced insulin deficiency. In cultured hepatocytes, we observed that expressions of ACSL1 and -5 were stimulated by insulin signaling. Results in cultured cells also showed that blunting insulin signaling by the PI3K inhibitor LY-294002 prevented fat accumulation, oxidative stress, and insulin resistance induced by the prolonged exposure to either insulin or oleate plus sera that normally contain insulin. Finally, knockdown of the insulin receptor prevented the oxidative stress and insulin resistance induced by the prolonged exposure to insulin or oleate plus sera. Together, our results show that insulin and insulin signaling are required for fat induction of insulin resistance in mice and cultured mouse hepatocytes. PMID:21586696

  15. Islet cell transplantation for the treatment of type 1 diabetes: recent advances and future challenges

    Directory of Open Access Journals (Sweden)

    Bruni A

    2014-06-01

    Full Text Available Anthony Bruni, Boris Gala-Lopez, Andrew R Pepper, Nasser S Abualhassan, AM James Shapiro Clinical Islet Transplant Program and Department of Surgery, University of Alberta, Edmonton, AB, Canada Abstract: Islet transplantation is a well-established therapeutic treatment for a subset of patients with complicated type I diabetes mellitus. Prior to the Edmonton Protocol, only 9% of the 267 islet transplant recipients since 1999 were insulin independent for >1 year. In 2000, the Edmonton group reported the achievement of insulin independence in seven consecutive patients, which in a collaborative team effort propagated expansion of clinical islet transplantation centers worldwide in an effort to ameliorate the consequences of this disease. To date, clinical islet transplantation has established improved success with insulin independence rates up to 5 years post-transplant with minimal complications. In spite of marked clinical success, donor availability and selection, engraftment, and side effects of immunosuppression remain as existing obstacles to be addressed to further improve this therapy. Clinical trials to improve engraftment, the availability of insulin-producing cell sources, as well as alternative transplant sites are currently under investigation to expand treatment. With ongoing experimental and clinical studies, islet transplantation continues to be an exciting and attractive therapy to treat type I diabetes mellitus with the prospect of shifting from a treatment for some to a cure for all. Keywords: islet transplantation, type I diabetes mellitus, Edmonton Protocol, engraftment, immunosuppression

  16. Islet cell transplantation for the treatment of type 1 diabetes: recent advances and future challenges

    Science.gov (United States)

    Bruni, Anthony; Gala-Lopez, Boris; Pepper, Andrew R; Abualhassan, Nasser S; Shapiro, AM James

    2014-01-01

    Islet transplantation is a well-established therapeutic treatment for a subset of patients with complicated type I diabetes mellitus. Prior to the Edmonton Protocol, only 9% of the 267 islet transplant recipients since 1999 were insulin independent for >1 year. In 2000, the Edmonton group reported the achievement of insulin independence in seven consecutive patients, which in a collaborative team effort propagated expansion of clinical islet transplantation centers worldwide in an effort to ameliorate the consequences of this disease. To date, clinical islet transplantation has established improved success with insulin independence rates up to 5 years post-transplant with minimal complications. In spite of marked clinical success, donor availability and selection, engraftment, and side effects of immunosuppression remain as existing obstacles to be addressed to further improve this therapy. Clinical trials to improve engraftment, the availability of insulin-producing cell sources, as well as alternative transplant sites are currently under investigation to expand treatment. With ongoing experimental and clinical studies, islet transplantation continues to be an exciting and attractive therapy to treat type I diabetes mellitus with the prospect of shifting from a treatment for some to a cure for all. PMID:25018643

  17. Liposome-mediated transfer of IL-1 receptor antagonist gene to dispersed islet cells does not prevent recurrence of disease in syngeneically transplanted NOD mice

    DEFF Research Database (Denmark)

    Saldeen, J; Sandler, S; Bendtzen, K

    2000-01-01

    transplanted non-obese diabetic (NOD) mice. NOD mouse islet cells were transfected using liposome-mediated gene transfer with a human IL-1ra cDNA construct and transplanted two days later to prediabetic NOD mice. Graft infiltration and destruction were monitored three, five and eight days posttransplantation...... by histology and determination of insulin and cytokine content. IL-1ra gene transfer resulted in transient expression of IL-1ra protein in islet cells in vitro as assessed by ELISA and of IL-1ra mRNA in transplanted islets as revealed by RT-PCR. However, both control and IL-1ra transfected NOD grafts exhibited......IL-1beta is cytotoxic to pancreatic beta-cells in vitro but its role in the vicinity of beta-cells in vivo is unknown. We explored whether liposome-mediated transfer of the interleukin 1 receptor antagonist (IL-1ra) gene to islet cells might prevent recurrence of disease in syngeneically...

  18. A novel high-throughput assay for islet respiration reveals uncoupling of rodent and human islets.

    Directory of Open Access Journals (Sweden)

    Jakob D Wikstrom

    Full Text Available The pancreatic beta cell is unique in its response to nutrient by increased fuel oxidation. Recent studies have demonstrated that oxygen consumption rate (OCR may be a valuable predictor of islet quality and long term nutrient responsiveness. To date, high-throughput and user-friendly assays for islet respiration are lacking. The aim of this study was to develop such an assay and to examine bioenergetic efficiency of rodent and human islets.The XF24 respirometer platform was adapted to islets by the development of a 24-well plate specifically designed to confine islets. The islet plate generated data with low inter-well variability and enabled stable measurement of oxygen consumption for hours. The F1F0 ATP synthase blocker oligomycin was used to assess uncoupling while rotenone together with myxothiazol/antimycin was used to measure the level of non-mitochondrial respiration. The use of oligomycin in islets was validated by reversing its effect in the presence of the uncoupler FCCP. Respiratory leak averaged to 59% and 49% of basal OCR in islets from C57Bl6/J and FVB/N mice, respectively. In comparison, respiratory leak of INS-1 cells and C2C12 myotubes was measured to 38% and 23% respectively. Islets from a cohort of human donors showed a respiratory leak of 38%, significantly lower than mouse islets.The assay for islet respiration presented here provides a novel tool that can be used to study islet mitochondrial function in a relatively high-throughput manner. The data obtained in this study shows that rodent islets are less bioenergetically efficient than human islets as well as INS1 cells.

  19. Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

    Energy Technology Data Exchange (ETDEWEB)

    Lubaczeuski, C.; Balbo, S.L. [Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil); Ribeiro, R.A. [Universidade Federal do Rio de Janeiro, Macaé, RJ (Brazil); Vettorazzi, J.F.; Santos-Silva, J.C.; Carneiro, E.M. [Laboratório de Pâncreas Endócrino e Metabolismo, Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP (Brazil); Bonfleur, M.L. [Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil)

    2015-02-24

    The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca{sup 2+} mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca{sup 2+} mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats.

  20. Hormone-sensitive lipase null mice exhibit signs of impaired insulin sensitivity whereas insulin secretion is intact

    DEFF Research Database (Denmark)

    Mulder, Hindrik; Sörhede-Winzell, Maria; Contreras, Juan Antonio

    2003-01-01

    of increased amounts of insulin. Impaired insulin sensitivity was further indicated by retarded glucose disposal during an insulin tolerance test. A euglycemic hyperinsulinemic clamp revealed that hepatic glucose production was insufficiently blocked by insulin in HSL null mice. In vitro, insulin......-stimulated glucose uptake into soleus muscle, and lipogenesis in adipocytes were moderately reduced, suggesting additional sites of insulin resistance. Morphometric analysis of pancreatic islets revealed a doubling of beta-cell mass in HSL null mice, which is consistent with an adaptation to insulin resistance....... Insulin secretion in vitro, examined by perifusion of isolated islets, was not impacted by HSL deficiency. Thus, HSL deficiency results in a moderate impairment of insulin sensitivity in multiple target tissues of the hormone but is compensated by hyperinsulinemia....

  1. A preclinical evaluation of alternative site for islet allotransplantation.

    Directory of Open Access Journals (Sweden)

    Chengshi Wang

    Full Text Available The bone marrow cavity (BMC has recently been identified as an alternative site to the liver for islet transplantation. This study aimed to compare the BMC with the liver as an islet allotransplantation site in diabetic monkeys. Diabetes was induced in Rhesus monkeys using streptozocin, and the monkeys were then divided into the following three groups: Group1 (islets transplanted in the liver with immunosuppressant, Group 2 (islets transplanted in the tibial BMC, and Group 3 (islets transplanted in the tibial BMC with immunosuppressant. The C-peptide and blood glucose levels were preoperatively measured. An intravenous glucose tolerance test (IVGTT was conducted to assess graft function, and complete blood cell counts were performed to assess cell population changes. Cytokine expression was measured using an enzyme-linked immune sorbent assay (ELISA and MILLIPLEX. Five monkeys in Group 3 exhibited a significantly increased insulin-independent time compared with the other groups (Group 1: 78.2 ± 19.0 days; Group 2: 58.8 ± 17.0 days; Group 3: 189.6 ± 26.2 days and demonstrated increases in plasma C-peptide 4 months after transplantation. The infusion procedure was not associated with adverse effects. Functional islets in the BMC were observed 225 days after transplantation using the dithizone (DTZ and insulin/glucagon stains. Our results showed that allogeneic islets transplanted in the BMC of diabetic Rhesus monkeys remained alive and functional for a longer time than those transplanted in the liver. This study was the first successful demonstration of allogeneic islet engraftment in the BMC of non-human primates (NHPs.

  2. Ethanolic Extract of Butea monosperma Leaves Elevate Blood Insulin Level in Type 2 Diabetic Rats, Stimulate Insulin Secretion in Isolated Rat Islets, and Enhance Hepatic Glycogen Formation

    Directory of Open Access Journals (Sweden)

    Mehdi Bin Samad

    2014-01-01

    Full Text Available We measured a vast range of parameters, in an attempt to further elucidate previously claimed antihyperglycemic activity of Butea monosperma. Our study clearly negates the possibility of antidiabetic activity by inhibited gastrointestinal enzyme action or by reduced glucose absorption. Reduction of fasting and postprandial glucose level was reconfirmed (P<0.05. Improved serum lipid profile via reduced low density lipoprotein (LDL, cholesterol, triglycerides (TG, and increased high density lipoprotein (HDL was also reestablished (P<0.05. Significant insulin secretagogue activity of B. monosperma was found in serum insulin assay of B. monosperma treated type 2 diabetic rats (P<0.01. This was further ascertained by our study on insulin secretion on isolated rat islets (P<0.05. Improved sensitivity of glucose was shown by the significant increase in hepatic glycogen deposition (P<0.05. Hence, we concluded that antihyperglycemic activity of B. monosperma was mediated by enhanced insulin secretion and enhanced glycogen formation in the liver.

  3. Application of Rotating Wall Vessel (RWV) Cell Culture for Pancreas Islet Cell Transplantation

    Science.gov (United States)

    Rutzky, Lynne P.

    1998-01-01

    Type I insulin-dependent diabetes mellitus (IDDM) remains a major cause of morbidity and mortality in both pediatric and adult populations, despite significant advances in medical management. While insulin therapy treats symptoms of acute diabetes, it fails to prevent chronic complications such as microvascular disease, blindness, neuropathy, and chronic renal failure. Strict control of blood glucose concentrations delays but does not prevent the onset and progression of secondary complications. Although, whole pancreas transplantation restores physiological blood glucose levels, a continuous process of allograft rejection causes vascular and exocrine-related complications. Recent advances in methods for isolation and purification of pancreatic islets make transplantation of islet allografts an attractive alternative to whole pancreas transplantation. However, immunosuppressive drugs are necessary to prevent rejection of islet allografts and many of these drugs are known to be toxic to the islets. Since auto-transplants of isolated islets following total pancreatectomy survive and function in vivo, it is apparent that a major obstacle to successful clinical islet transplantation is the immunogenicity of the islet allografts.

  4. Islet alloautotransplantation: Allogeneic pancreas transplantation followed by transplant pancreatectomy and islet transplantation.

    Science.gov (United States)

    Nijhoff, M F; Dubbeld, J; van Erkel, A R; van der Boog, P J M; Rabelink, T J; Engelse, M A; de Koning, E J P

    2018-04-01

    Simultaneous pancreas-kidney (SPK) transplantation is an important treatment option for patients with type 1 diabetes (T1D) and end-stage renal disease (ESRD). Due to complications, in up to 10% of patients, allograft pancreatectomy is necessary shortly after transplantation. Usually the donor pancreas is discarded. Here, we report on a novel procedure to rescue endocrine tissue after allograft pancreatectomy. A 39-year-old woman with T1D and ESRD who had undergone SPK transplantation required emergency allograft pancreatectomy due to bleeding at the vascular anastomosis. Islets were isolated from the removed pancreas allograft, and almost 480 000 islet equivalents were infused into the portal vein. The patient recovered fully. After 3 months, near-normal mixed meal test (fasting glucose 7.0 mmol/L, 2-hour glucose 7.5 mmol/L, maximal stimulated C-peptide 3.25 nmol/L, without insulin use in the preceding 36 hours) was achieved. Glycated hemoglobin while taking a low dose of long-acting insulin was 32.7 mmol/mol hemoglobin (5.3%). When a donor pancreas is lost after transplantation, rescue β cell therapy by islet alloautotransplantation enables optimal use of scarce donor pancreata to optimize glycemic control without additional HLA alloantigen exposure. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  5. Current issues in allogeneic islet transplantation.

    Science.gov (United States)

    Chang, Charles A; Lawrence, Michael C; Naziruddin, Bashoo

    2017-10-01

    Transplantation of allogenic pancreatic islets is a minimally invasive treatment option to control severe hypoglycemia and dependence on exogenous insulin among type 1 diabetes (T1D) patients. This overview summarizes the current issues and progress in islet transplantation outcomes and research. Several clinical trials from North America and other countries have documented the safety and efficacy of clinical islet transplantation for T1D patients with impaired hypoglycemia awareness. A recently completed phase 3 clinical trial allows centres in the United States to apply for a Food and Drug Administration Biologics License for the procedure. Introduction of anti-inflammatory drugs along with T-cell depleting induction therapy has significantly improved long-term function of transplanted islets. Research into islet biomarkers, immunosuppression, extrahepatic transplant sites and potential alternative beta cell sources is driving further progress. Allogeneic islet transplantation has vastly improved over the past two decades. Success in restoration of glycemic control and hypoglycemic awareness after islet transplantation has been further highlighted by clinical trials. However, lack of effective strategies to maintain long-term islet function and insufficient sources of donor tissue still impose limitations to the widespread use of islet transplantation. In the United States, wide adoption of this technology still awaits regulatory approval and, importantly, a financial mechanism to support the use of this technology.

  6. Islet Microencapsulation: Strategies and Clinical Status in Diabetes.

    Science.gov (United States)

    Omami, Mustafa; McGarrigle, James J; Reedy, Mick; Isa, Douglas; Ghani, Sofia; Marchese, Enza; Bochenek, Matthew A; Longi, Maha; Xing, Yuan; Joshi, Ira; Wang, Yong; Oberholzer, José

    2017-07-01

    Type 1 diabetes mellitus (T1DM) is an autoimmune disease that results from the destruction of insulin-producing pancreatic β cells in the islets of Langerhans. Islet cell transplantation has become a successful therapy for specific patients with T1DM with hypoglycemic unawareness. The reversal of T1DM by islet transplantation is now performed at many major medical facilities throughout the world. However, many challenges must still be overcome in order to achieve continuous, long-term successful transplant outcomes. Two major obstacles to this therapy are a lack of islet cells for transplantation and the need for life-long immunosuppressive treatment. Microencapsulation is seen as a technology that can overcome both these limitations of islet cell transplantation. This review depicts the present state of microencapsulated islet transplantation. Microencapsulation can play a significant role in overcoming the need for immunosuppression and lack of donor islet cells. This review focuses on microencapsulation and the clinical status of the technology in combating T1DM.

  7. A role for polyamines in glucose-stimulated insulin-gene expression.

    Science.gov (United States)

    Welsh, N

    1990-01-01

    The aim of the present study was to evaluate the possible role for polyamines in the glucose regulation of the metabolism of insulin mRNA of pancreatic islet cells. For this purpose islets were prepared from adult mice and cultured for 2 days in culture medium RPMI 1640 containing 3.3 mM- or 16.7 mM-glucose with or without the addition of the inhibitors of polyamine biosynthesis difluoromethylornithine (DFMO) and ethylglyoxal bis(guanylhydrazone) (EGBG). Culture at the high glucose concentration increased the islet contents of both insulin mRNA and polyamines. The synthesis of total RNA, total islet polyamines and polyamines associated with islet nuclei was also increased. When the combination of DFMO and EGBG was added in the presence of 16.7 mM-glucose, low contents of insulin mRNA, spermine and spermidine were observed. Total islet polyamine synthesis was also depressed by DFMO + EGBG, unlike islet biosynthesis of polyamines associated with nuclei, which was not equally decreased by the polyamine-synthesis inhibitors. Total RNA synthesis and turnover was not affected by DFMO + EGBG. Finally, actinomycin D attenuated the glucose-induced enhancement of insulin mRNA, and cycloheximide counteracted the insulin-mRNA attenuation induced by inhibition of polyamine synthesis. It is concluded that the glucose-induced increase in insulin mRNA is paralleled by increased contents and rates of polyamine biosynthesis and that an attenuation of the increase in polyamines prevents the increase in insulin mRNA. In addition, the results are compatible with the view that polyamines exert their effects on insulin mRNA mainly by increasing the stability of this messenger. PMID:2241922

  8. Cost and clinical outcome of islet transplantation in Norway 2010-2015.

    Science.gov (United States)

    Schive, Simen W; Foss, Aksel; Sahraoui, Afaf; Kloster-Jensen, Kristine; Hafsahl, Geir; Kvalheim, Gunnar; Lundgren, Torbjørn; von Zur-Mühlen, Bengt; Felldin, Marie; Rafael, Ehab; Lempinen, Marko; Korsgren, Olle; Jenssen, Trond G; Mishra, Vinod; Scholz, Hanne

    2017-01-01

    Islet transplantation is a minimally invasive β-cell replacement strategy. Islet transplantation is a reimbursed treatment in Norway. Here, we summarize the cost and clinical outcome of 31 islet transplantations performed at Oslo University Hospital (OUS) from January 2010 to June 2015. Patients were retrospectively divided into three groups. Thirteen patients received either one or two islet transplantation alone (ITA), while five patients received islet transplantation after previous solid organ transplantation. For the group receiving 2 ITA, Kaplan-Meier estimates show an insulin independence of 20% more than 4 years after their last transplantation. An estimated 70% maintain at least partial graft function, defined as fasting C-peptide >0.1 nmol L -1 , and 47% maintain a HbA1c below 6.5% or 2 percent points lower than before ITA. For all groups combined, we estimate that 44% of the patients have a 50% reduction in insulin requirement 4 years after the initial islet transplantation. The average cost for an islet transplantation procedure was 347 297±60 588 NOK, or 35 424±6182 EUR, of which isolation expenses represent 34%. We hereby add to the common pool of growing experience with islet transplantation and also describe the cost of the treatment at our center. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Efficient and simple production of insulin-producing cells from embryonal carcinoma stem cells using mouse neonate pancreas extract, as a natural inducer.

    Directory of Open Access Journals (Sweden)

    Marzieh Ebrahimie

    Full Text Available An attractive approach to replace the destroyed insulin-producing cells (IPCs is the generation of functional β cells from stem cells. Embryonal carcinoma (EC stem cells are pluripotent cells which can differentiate into all cell types. The present study was carried out to establish a simple nonselective inductive culture system for generation of IPCs from P19 EC cells by 1-2 weeks old mouse pancreas extract (MPE. Since, mouse pancreatic islets undergo further remodeling and maturation for 2-3 weeks after birth, we hypothesized that the mouse neonatal MPE contains essential factors to induce in vitro differentiation of pancreatic lineages. Pluripotency of P19 cells were first confirmed by expression analysis of stem cell markers, Oct3/4, Sox-2 and Nanog. In order to induce differentiation, the cells were cultured in a medium supplemented by different concentrations of MPE (50, 100, 200 and 300 µg/ml. The results showed that P19 cells could differentiate into IPCs and form dithizone-positive cell clusters. The generated P19-derived IPCs were immunoreactive to proinsulin, insulin and insulin receptor beta. The expression of pancreatic β cell genes including, PDX-1, INS1 and INS2 were also confirmed. The peak response at the 100 µg/ml MPE used for investigation of EP300 and CREB1 gene expression. When stimulated with glucose, these cells synthesized and secreted insulin. Network analysis of the key transcription factors (PDX-1, EP300, CREB1 during the generation of IPCs resulted in introduction of novel regulatory candidates such as MIR17, and VEZF1 transcription factors, as well as MORN1, DKFZp761P0212, and WAC proteins. Altogether, we demonstrated the possibility of generating IPCs from undifferentiated EC cells, with the characteristics of pancreatic β cells. The derivation of pancreatic cells from EC cells which are ES cell siblings would provide a valuable experimental tool in study of pancreatic development and function as well as rapid

  10. Islet graft survival and function: concomitant culture and transplantation with vascular endothelial cells in diabetic rats.

    Science.gov (United States)

    Pan, Xiaoming; Xue, Wujun; Li, Yang; Feng, Xinshun; Tian, Xiaohui; Ding, Chenguang

    2011-12-15

    Human islet transplantation is a great potential therapy for type I diabetes. To investigate islet graft survival and function, we recently showed the improved effects after co-culture and co-transplantation with vascular endothelial cells (ECs) in diabetic rats. ECs were isolated, and the viability of isolated islets was assessed in two groups (standard culture group and co-culture group with ECs). Then streptozotocin-induced diabetic rats were divided into four groups before islet transplantation as follows: group A with infusion of islet grafts; group B with combined vascular ECs and islet grafts; groups C and D as controls with single ECs infusion and phosphate-buffered saline injection, respectively. Blood glucose and insulin concentrations were measured daily. Expression of vascular endothelial growth factor was investigated by immunohistochemical staining. The mean microvascular density was also calculated. More than 90% of acridine orange-propidium iodide staining positive islets demonstrated normal morphology while co-cultured with ECs for 7 days. Compared with standard control, insulin release assays showed a significantly higher simulation index in co-culture group except for the first day (Ptransplantation, there was a significant difference in concentrations of blood glucose and insulin among these groups after 3 days (Pislet group (P=0.04). Co-culture with ECs in vitro could improve the survival and function of isolated rat islet, and co-transplantation of islets with ECs could effectively prolong the islet graft survival in diabetic rats.

  11. Serum Cytokines as Biomarkers in Islet Cell Transplantation for Type 1 Diabetes.

    Directory of Open Access Journals (Sweden)

    Cornelis R van der Torren

    Full Text Available Islet cell transplantation holds a potential cure for type 1 diabetes, but many islet recipients do not reach long-lasting insulin independence. In this exploratory study, we investigated whether serum cytokines, chemokines and adipokines are associated with the clinical outcome of islet transplantation.Thirteen islet transplant patients were selected on basis of good graft function (reaching insulin independence or insufficient engraftment (insulin requiring from our cohort receiving standardized grafts and immune suppressive therapy. Patients reaching insulin independence were divided in those with continued (>12 months versus transient (<6 months insulin independence. A panel of 94 proteins including cytokines and adipokines was measured in sera taken before and at one year after transplantation using a validated multiplex immunoassay platform.Ninety serum proteins were detectable in concentrations varying markedly among patients at either time point. Thirteen markers changed after transplantation, while another seven markers changed in a clinical subpopulation. All other markers remained unaffected after transplantation under generalized immunosuppression. Patterns of cytokines could distinguish good graft function from insufficient function including IFN-α, LIF, SCF and IL-1RII before and after transplantation, by IL-16, CCL3, BDNF and M-CSF only before and by IL-22, IL-33, KIM-1, S100A12 and sCD14 after transplantation. Three other proteins (Leptin, Cathepsin L and S100A12 associated with loss of temporary graft function before or after transplantation.Distinct cytokine signatures could be identified in serum that predict or associate with clinical outcome. These serum markers may help guiding patient selection and choice of immunotherapy, or act as novel drug targets in islet transplantation.

  12. Effect of 5'-flanking sequence deletions on expression of the human insulin gene in transgenic mice

    DEFF Research Database (Denmark)

    Fromont-Racine, M; Bucchini, D; Madsen, O

    1990-01-01

    Expression of the human insulin gene was examined in transgenic mouse lines carrying the gene with various lengths of DNA sequences 5' to the transcription start site (+1). Expression of the transgene was demonstrated by 1) the presence of human C-peptide in urine, 2) the presence of specific...... of the transgene was observed in cell types other than beta-islet cells....

  13. Glucose cycling is markedly enhanced in pancreatic islets of obese hyperglycemic mice

    International Nuclear Information System (INIS)

    Khan, A.; Chandramouli, V.; Ostenson, C.G.; Berggren, P.O.; Loew, H.L.; Landau, B.R.; Efendic, S.

    1990-01-01

    Pancreatic islets from fed 7-month old lean and obese hyperglycemic mice (ob/ob) were incubated with 3H2O and 5.5 mM or 16.7 mM glucose. Incorporation of 3H into the medium glucose was taken as the measure of glucose-6-P hydrolysis to glucose. Glucose utilization was measured from the yield of 3H2O from [5-3H]glucose. Only 3-4% of the glucose phosphorylated was dephosphorylated by the lean mouse islets irrespective of the glucose concentration. In contrast, the ob/ob mouse islets at 5.5 mM glucose dephosphorylated 18% of the glucose phosphorylated and 30% at 16.7 mM. Thus, the islets of hyperglycemic mice demonstrate increased glucose cycling as compared to the islets of normoglycemic lean mice

  14. 3-D Imaging Reveals Participation of Donor Islet Schwann Cells and Pericytes in Islet Transplantation and Graft Neurovascular Regeneration.

    Science.gov (United States)

    Juang, Jyuhn-Huarng; Kuo, Chien-Hung; Peng, Shih-Jung; Tang, Shiue-Cheng

    2015-02-01

    The primary cells that participate in islet transplantation are the endocrine cells. However, in the islet microenvironment, the endocrine cells are closely associated with the neurovascular tissues consisting of the Schwann cells and pericytes, which form sheaths/barriers at the islet exterior and interior borders. The two cell types have shown their plasticity in islet injury, but their roles in transplantation remain unclear. In this research, we applied 3-dimensional neurovascular histology with cell tracing to reveal the participation of Schwann cells and pericytes in mouse islet transplantation. Longitudinal studies of the grafts under the kidney capsule identify that the donor Schwann cells and pericytes re-associate with the engrafted islets at the peri-graft and perivascular domains, respectively, indicating their adaptability in transplantation. Based on the morphological proximity and cellular reactivity, we propose that the new islet microenvironment should include the peri-graft Schwann cell sheath and perivascular pericytes as an integral part of the new tissue.

  15. 3-D Imaging Reveals Participation of Donor Islet Schwann Cells and Pericytes in Islet Transplantation and Graft Neurovascular Regeneration

    Directory of Open Access Journals (Sweden)

    Jyuhn-Huarng Juang

    2015-02-01

    Full Text Available The primary cells that participate in islet transplantation are the endocrine cells. However, in the islet microenvironment, the endocrine cells are closely associated with the neurovascular tissues consisting of the Schwann cells and pericytes, which form sheaths/barriers at the islet exterior and interior borders. The two cell types have shown their plasticity in islet injury, but their roles in transplantation remain unclear. In this research, we applied 3-dimensional neurovascular histology with cell tracing to reveal the participation of Schwann cells and pericytes in mouse islet transplantation. Longitudinal studies of the grafts under the kidney capsule identify that the donor Schwann cells and pericytes re-associate with the engrafted islets at the peri-graft and perivascular domains, respectively, indicating their adaptability in transplantation. Based on the morphological proximity and cellular reactivity, we propose that the new islet microenvironment should include the peri-graft Schwann cell sheath and perivascular pericytes as an integral part of the new tissue.

  16. Mitochondrial Dysfunction Contributes to Impaired Insulin Secretion in INS-1 Cells with Dominant-negative Mutations of HNF-1α and in HNF-1α-deficient Islets*

    OpenAIRE

    Pongratz, Rebecca L.; Kibbey, Richard G.; Kirkpatrick, Clare L.; Zhao, Xiaojian; Pontoglio, Marco; Yaniv, Moshe; Wollheim, Claes B.; Shulman, Gerald I.; Cline, Gary W.

    2009-01-01

    Maturity Onset Diabetes of the Young-type 3 (MODY-3) has been linked to mutations in the transcription factor hepatic nuclear factor (HNF)-1α, resulting in deficiency in glucose-stimulated insulin secretion. In INS-1 cells overexpressing doxycycline-inducible HNF-1α dominant-negative (DN-) gene mutations, and islets from Hnf-1α knock-out mice, insulin secretion was impaired in response to glucose (15 mm) and other nutrient secretagogues. Decreased rates of insulin secretion in response to glu...

  17. Separation of empty microcapsules after microencapsulation of porcine neonatal islets.

    Science.gov (United States)

    Shin, Soojeong; Yoo, Young Je

    2013-12-01

    Pancreatic islet transplantation is used to treat diabetes mellitus that has minimal complications and avoids hypoglycemic shock. Conformal microencapsulation of pancreatic islets improves their function by blocking immunogenic molecules while protecting fragile islets. However, production of empty alginate capsules during microencapsulation causes enlargement of the transplantation volume of the encapsulated islets and interferes with efficient transfer of nutrients and insulin. In this study, empty alginate capsules were separated after microencapsulation of neonatal porcine islet-like cell clusters (NPCC) using density-gradient centrifugation. Densities of NPCC and alginate capsules were determined using Percoll. Encapsulation products following alginate removal were 97 % of products, with less than 10 % of the capsules remaining empty. The viability of this process compared with manually-selected encapsulated islets indicates the separation process does not harm islets.

  18. Identification and characterization of insulin receptors on foetal-mouse brain-cortical cells.

    OpenAIRE

    Van Schravendijk, C F; Hooghe-Peters, E L; De Meyts, P; Pipeleers, D G

    1984-01-01

    The occurrence of insulin receptors was investigated in freshly dissociated brain-cortical cells from mouse embryos. By analogy with classical insulin-binding cell types, binding of 125I-insulin to foetal brain-cortical cells was time- and pH-dependent, only partially reversible, and competed for by unlabelled insulin and closely related peptides. Desalanine-desasparagine-insulin, pig proinsulin, hagfish insulin and turkey insulin were respectively 2%, 4%, 2% and 200% as potent as bovine insu...

  19. UCP2 mRNA expression is dependent on glucose metabolism in pancreatic islets

    International Nuclear Information System (INIS)

    Dalgaard, Louise T.

    2012-01-01

    Highlights: ► UCP2 mRNA levels are decreased in islets of Langerhans from glucokinase deficient mice. ► UCP2 mRNA up-regulation by glucose is dependent on glucokinase. ► Absence of UCP2 increases GSIS of glucokinase heterozygous pancreatic islets. ► This may protect glucokinase deficient mice from hyperglycemic damages. -- Abstract: Uncoupling Protein 2 (UCP2) is expressed in the pancreatic β-cell, where it partially uncouples the mitochondrial proton gradient, decreasing both ATP-production and glucose-stimulated insulin secretion (GSIS). Increased glucose levels up-regulate UCP2 mRNA and protein levels, but the mechanism for UCP2 up-regulation in response to increased glucose is unknown. The aim was to examine the effects of glucokinase (GK) deficiency on UCP2 mRNA levels and to characterize the interaction between UCP2 and GK with regard to glucose-stimulated insulin secretion in pancreatic islets. UCP2 mRNA expression was reduced in GK+/− islets and GK heterozygosity prevented glucose-induced up-regulation of islet UCP2 mRNA. In contrast to UCP2 protein function UCP2 mRNA regulation was not dependent on superoxide generation, but rather on products of glucose metabolism, because MnTBAP, a superoxide dismutase mimetic, did not prevent the glucose-induced up-regulation of UCP2. Glucose-stimulated insulin secretion was increased in UCP2−/− and GK+/− islets compared with GK+/− islets and UCP2 deficiency improved glucose tolerance of GK+/− mice. Accordingly, UCP2 deficiency increased ATP-levels of GK+/− mice. Thus, the compensatory down-regulation of UCP2 is involved in preserving the insulin secretory capacity of GK mutant mice and might also be implicated in limiting disease progression in MODY2 patients.

  20. Isolation of Human Islets for Autologous Islet Transplantation in Children and Adolescents with Chronic Pancreatitis

    Directory of Open Access Journals (Sweden)

    Rita Bottino

    2012-01-01

    Full Text Available Chronic pancreatitis is an inflammatory disease of the pancreas that causes permanent changes in the function and structure of the pancreas. It is most commonly a complication of cystic fibrosis or due to a genetic predisposition. Chronic pancreatitis generally presents symptomatically as recurrent abdominal pain, which becomes persistent over time. The pain eventually becomes disabling. Once specific medical treatments and endoscopic interventions are no longer efficacious, total pancreatectomy is the alternative of choice for helping the patient achieve pain control. While daily administrations of digestive enzymes cannot be avoided, insulin-dependent diabetes can be prevented by transplanting the isolated pancreatic islets back to the patient. The greater the number of islets infused, the greater the chance to prevent or at least control the effects of surgical diabetes. We present here a technical approach for the isolation and preservation of the islets proven to be efficient to obtain high numbers of islets, favoring the successful treatment of young patients.

  1. Beating diabetes: strategies to improve pancreatic islet transplantation

    NARCIS (Netherlands)

    Hilderink, J.

    2013-01-01

    Type 1 diabetes is a chronic disease that is caused by nearly complete destruction of insulin producing beta-cells in the islets of Langerhans, affecting approximately 25 million people worldwide. Prior to the discovery of insulin, diabetes most certainly led to death. To date, patients with type 1

  2. The Spleen Is an Ideal Site for Inducing Transplanted Islet Graft Expansion in Mice.

    Directory of Open Access Journals (Sweden)

    Takeshi Itoh

    Full Text Available Alternative islet transplantation sites have the potential to reduce the marginal number of islets required to ameliorate hyperglycemia in recipients with diabetes. Previously, we reported that T cell leukemia homeobox 1 (Tlx1+ stem cells in the spleen effectively regenerated into insulin-producing cells in the pancreas of non-obese diabetic mice with end-stage disease. Thus, we investigated the spleen as a potential alternative islet transplantation site. Streptozotocin-induced diabetic C57BL/6 mice received syngeneic islets into the portal vein (PV, beneath the kidney capsule (KC, or into the spleen (SP. The marginal number of islets by PV, KC, or SP was 200, 100, and 50, respectively. Some plasma inflammatory cytokine levels in the SP group were significantly lower than those of the PV group after receiving a marginal number of islets, indicating reduced inflammation in the SP group. Insulin contents were increased 280 days after islet transplantation compared with those immediately following transplantation (p<0.05. Additionally, Tlx1-related genes, including Rrm2b and Pla2g2d, were up-regulated, which indicates that islet grafts expanded in the spleen. The spleen is an ideal candidate for an alternative islet transplantation site because of the resulting reduced inflammation and expansion of the islet graft.

  3. Cytokines cause functional and structural damage to isolated islets of Langerhans

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Bendtzen, K; Bendixen, G

    1985-01-01

    Cytokines are soluble, antigen non-specific, non-immunoglobulin mediators produced and secreted by blood mononuclear cells interacting in the cellular immune-response. To test the possibility that cytokines participate in the autoimmune destruction of the pancreatic beta-cells leading to insulin-......-release, and contents of insulin and glucagon in islets incubated with cytokine-rich supernatants were markedly reduced. This impairment of islet function was due to a cytotoxic effect of cytokine-rich supernatants as judged by disintegration of normal light-microscopic morphology....

  4. Striated Muscle as Implantation Site for Transplanted Pancreatic Islets

    Directory of Open Access Journals (Sweden)

    Daniel Espes

    2011-01-01

    Full Text Available Islet transplantation is an attractive treatment for selected patients with brittle type 1 diabetes. In the clinical setting, intraportal transplantation predominates. However, due to extensive early islet cell death, the quantity of islets needed to restore glucose homeostasis requires in general a minimum of two donors. Moreover, the deterioration of islet function over time results in few insulin-independent patients after five-year followup. Specific obstacles to the success of islet transplantation include site-specific concerns for the liver such as the instant blood mediated inflammatory reaction, islet lipotoxicity, low oxygen tension, and poor revascularization, impediments that have led to the developing interest for alternative implantation sites over recent years. Within preclinical settings, several alternative sites have now been investigated and proven favorable in various aspects. Muscle is considered a very promising site and has physiologically properties and technical advantages that could make it optimal for islet transplantation.

  5. Successful pregnancy and delivery after simultaneous islet-kidney transplantation.

    Science.gov (United States)

    Assalino, Michela; Podetta, Michele; Demuylder-Mischler, Sandrine; Francini, Katyuska; Pernin, Nadine; Randin, Jean-Pierre; Bosco, Domenico; Andres, Axel; Berney, Thierry

    2018-04-19

    Allogeneic islet of Langerhans transplantation is a recognized beta-cell replacement therapy for patients affected by type 1 diabetes mellitus. Type 1 diabetes mellitus is a condition associated with an increased risk of adverse outcomes for pregnant women and fetuses. We report the case of a 29-year-old woman with type 1 diabetes mellitus, who underwent successful allogeneic islet transplantation with simultaneous kidney transplantation. She achieved durable insulin independence after 2 islet infusions. Pregnancy was desired and planned 2 years after the last islet infusion. Multidisciplinary monitoring of pregnancy was carried out and the immunosuppressive regimen was adapted. Euglycemia was maintained throughout pregnancy without the need for exogenous insulin. After an uneventful pregnancy, she delivered on term an otherwise healthy male child with imperforate anus that was immediately surgically corrected. In conclusion, allogeneic islet transplantation is a suitable treatment for women of childbearing age with complicated type 1 diabetes mellitus, allowing physiologic glycemic control during pregnancy with a low risk of graft loss. This target can be achieved only by a tight multidisciplinary follow-up, including immunosuppressive therapy adaptation and adequate diabetes and obstetrical monitoring. © 2018 The American Society of Transplantation and the American Society of Transplant Surgeons.

  6. Salvage Islet Auto Transplantation After Relaparatomy.

    Science.gov (United States)

    Balzano, Gianpaolo; Nano, Rita; Maffi, Paola; Mercalli, Alessia; Melzi, Raffaelli; Aleotti, Francesca; Gavazzi, Francesca; Berra, Cesare; De Cobelli, Francesco; Venturini, Massimo; Magistretti, Paola; Scavini, Marina; Capretti, Giovanni; Del Maschio, Alessandro; Secchi, Antonio; Zerbi, Alessandro; Falconi, Massimo; Piemonti, Lorenzo

    2017-10-01

    To assess feasibility, safety, and metabolic outcome of islet auto transplantation (IAT) in patients undergoing completion pancreatectomy because of sepsis or bleeding after pancreatic surgery. From November 2008 to October 2016, approximately 22 patients were candidates to salvage IAT during emergency relaparotomy because of postpancreatectomy sepsis (n = 11) or bleeding (n = 11). Feasibility, efficacy, and safety of salvage IAT were compared with those documented in a cohort of 36 patients who were candidate to simultaneous IAT during nonemergency preemptive completion pancreatectomy through the pancreaticoduodenectomy. The percentage of candidates that received the infusion of islets was significantly lower in salvage IAT than simultaneous IAT (59.1% vs 88.9%, P = 0.008), mainly because of a higher rate of inadequate islet preparations. Even if microbial contamination of islet preparation was significantly higher in candidates to salvage IAT than in those to simultaneous IAT (78.9% vs 20%, P < 0.001), there was no evidence of a higher rate of complications related to the procedure. Median follow-up was 5.45 ± 0.52 years. Four (36%) of 11 patients reached insulin independence, 6 patients (56%) had partial graft function, and 1 patient (9%) had primary graft nonfunction. At the last follow-up visit, median fasting C-peptide was 0.43 (0.19-0.93) ng/mL; median insulin requirement was 0.38 (0.04-0.5) U/kg per day, and median HbA1c was 6.6% (5.9%-8.1%). Overall mortality, in-hospital mortality, metabolic outcome, graft survival, and insulin-free survival after salvage IAT were not different from those documented after simultaneous IAT. Our data demonstrate the feasibility, efficacy, and safety of salvage IAT after relaparotomy.

  7. Mesenchymal Stem Cells Enhance Allogeneic Islet Engraftment in Nonhuman Primates

    Science.gov (United States)

    Berman, Dora M.; Willman, Melissa A.; Han, Dongmei; Kleiner, Gary; Kenyon, Norman M.; Cabrera, Over; Karl, Julie A.; Wiseman, Roger W.; O'Connor, David H.; Bartholomew, Amelia M.; Kenyon, Norma S.

    2010-01-01

    OBJECTIVE To test the graft-promoting effects of mesenchymal stem cells (MSCs) in a cynomolgus monkey model of islet/bone marrow transplantation. RESEARCH DESIGN AND METHODS Cynomolgus MSCs were obtained from iliac crest aspirate and characterized through passage 11 for phenotype, gene expression, differentiation potential, and karyotype. Allogeneic donor MSCs were cotransplanted intraportally with islets on postoperative day (POD) 0 and intravenously with donor marrow on PODs 5 and 11. Recipients were followed for stabilization of blood glucose levels, reduction of exogenous insulin requirement (EIR), C-peptide levels, changes in peripheral blood T regulatory cells, and chimerism. Destabilization of glycemia and increases in EIR were used as signs of rejection; additional intravenous MSCs were administered to test the effect on reversal of rejection. RESULTS MSC phenotype and a normal karyotype were observed through passage 11. IL-6, IL-10, vascular endothelial growth factor, TGF-β, hepatocyte growth factor, and galectin-1 gene expression levels varied among donors. MSC treatment significantly enhanced islet engraftment and function at 1 month posttransplant (n = 8), as compared with animals that received islets without MSCs (n = 3). Additional infusions of donor or third-party MSCs resulted in reversal of rejection episodes and prolongation of islet function in two animals. Stable islet allograft function was associated with increased numbers of regulatory T-cells in peripheral blood. CONCLUSIONS MSCs may provide an important approach for enhancement of islet engraftment, thereby decreasing the numbers of islets needed to achieve insulin independence. Furthermore, MSCs may serve as a new, safe, and effective antirejection therapy. PMID:20622174

  8. Long-term effects of islet transplantation.

    Science.gov (United States)

    Holmes-Walker, D Jane; Kay, Thomas W H

    2016-10-01

    Islet transplantation has made great progress in recent years. This is a remarkable technical feat but raises the question of what the long-term benefits and risks are for type I diabetes recipients. Graft survival continues to improve, and recent multicenter studies show that islet transplantation is particularly effective to prevent hypoglycemic events even in those who do not become insulin-independent and to achieve excellent glycemic control. Concerns include histocompatability leucocyte antigen (HLA) sensitization and other risks including from immunosuppression that islet transplantation shares with other forms of allotransplantation. Reversal of hypoglycemia unawareness and protection from severe hypoglycemia events are two of the main benefits of islet transplantation and they persist for the duration of graft function. Islet transplantation compares favorably with other therapies for those with hypoglycemia unawareness, although new technologies have not been tested head-to-head with transplantation. HLA sensitization increases with time after transplantation especially if immunosuppression is ceased and is a risk for those who may require future transplantation as well as being associated with loss of graft function.

  9. Prevalence and predictive value of islet cell antibodies and insulin autoantibodies in women with gestational diabetes

    DEFF Research Database (Denmark)

    Damm, P; Kühl, C; Buschard, K

    1994-01-01

    The objective of the present study was to investigate the predictive value of islet cell antibodies (ICA) and insulin autoantibodies (IAA) for development of diabetes in women with previous gestational diabetes (GDM). Two hundred and forty-one previous diet-treated GDM patients and 57 women without...... for ICA were ICA-positive and three of these had Type 1 diabetes at follow-up, as well as three ICA-negative patients. The sensitivity, specificity, and predictive value of ICA-positivity for later development of diabetes were 50%, 99%, and 75%, respectively. None of the women was IAA-positive during...

  10. The Brain–to–Pancreatic Islet Neuronal Map Reveals Differential Glucose Regulation From Distinct Hypothalamic Regions

    Science.gov (United States)

    Rosario, Wilfredo; Singh, Inderroop; Wautlet, Arnaud; Patterson, Christa; Flak, Jonathan; Becker, Thomas C.; Ali, Almas; Tamarina, Natalia; Philipson, Louis H.; Enquist, Lynn W.; Myers, Martin G.

    2016-01-01

    The brain influences glucose homeostasis, partly by supplemental control over insulin and glucagon secretion. Without this central regulation, diabetes and its complications can ensue. Yet, the neuronal network linking to pancreatic islets has never been fully mapped. Here, we refine this map using pseudorabies virus (PRV) retrograde tracing, indicating that the pancreatic islets are innervated by efferent circuits that emanate from the hypothalamus. We found that the hypothalamic arcuate nucleus (ARC), ventromedial nucleus (VMN), and lateral hypothalamic area (LHA) significantly overlap PRV and the physiological glucose-sensing enzyme glucokinase. Then, experimentally lowering glucose sensing, specifically in the ARC, resulted in glucose intolerance due to deficient insulin secretion and no significant effect in the VMN, but in the LHA it resulted in a lowering of the glucose threshold that improved glucose tolerance and/or improved insulin sensitivity, with an exaggerated counter-regulatory response for glucagon secretion. No significant effect on insulin sensitivity or metabolic homeostasis was noted. Thus, these data reveal novel direct neuronal effects on pancreatic islets and also render a functional validation of the brain-to-islet neuronal map. They also demonstrate that distinct regions of the hypothalamus differentially control insulin and glucagon secretion, potentially in partnership to help maintain glucose homeostasis and guard against hypoglycemia. PMID:27207534

  11. The Brain-to-Pancreatic Islet Neuronal Map Reveals Differential Glucose Regulation From Distinct Hypothalamic Regions.

    Science.gov (United States)

    Rosario, Wilfredo; Singh, Inderroop; Wautlet, Arnaud; Patterson, Christa; Flak, Jonathan; Becker, Thomas C; Ali, Almas; Tamarina, Natalia; Philipson, Louis H; Enquist, Lynn W; Myers, Martin G; Rhodes, Christopher J

    2016-09-01

    The brain influences glucose homeostasis, partly by supplemental control over insulin and glucagon secretion. Without this central regulation, diabetes and its complications can ensue. Yet, the neuronal network linking to pancreatic islets has never been fully mapped. Here, we refine this map using pseudorabies virus (PRV) retrograde tracing, indicating that the pancreatic islets are innervated by efferent circuits that emanate from the hypothalamus. We found that the hypothalamic arcuate nucleus (ARC), ventromedial nucleus (VMN), and lateral hypothalamic area (LHA) significantly overlap PRV and the physiological glucose-sensing enzyme glucokinase. Then, experimentally lowering glucose sensing, specifically in the ARC, resulted in glucose intolerance due to deficient insulin secretion and no significant effect in the VMN, but in the LHA it resulted in a lowering of the glucose threshold that improved glucose tolerance and/or improved insulin sensitivity, with an exaggerated counter-regulatory response for glucagon secretion. No significant effect on insulin sensitivity or metabolic homeostasis was noted. Thus, these data reveal novel direct neuronal effects on pancreatic islets and also render a functional validation of the brain-to-islet neuronal map. They also demonstrate that distinct regions of the hypothalamus differentially control insulin and glucagon secretion, potentially in partnership to help maintain glucose homeostasis and guard against hypoglycemia. © 2016 by the American Diabetes Association.

  12. Oxygenated thawing and rewarming alleviate rewarming injury of cryopreserved pancreatic islets.

    Science.gov (United States)

    Komatsu, Hirotake; Barriga, Alyssa; Medrano, Leonard; Omori, Keiko; Kandeel, Fouad; Mullen, Yoko

    2017-05-06

    Pancreatic islet transplantation is an effective treatment for Type 1 diabetic patients to eliminate insulin injections; however, a shortage of donor organs hinders the widespread use. Although long-term islet storage, such as cryopreservation, is considered one of the key solutions, transplantation of cryopreserved islets is still not practical due to the extensive loss during the cryopreservation-rewarming process. We have previously reported that culturing islets in a hyperoxic environment is an effective treatment to prevent islet death from the hypoxic injury during culture. In this study, we explored the effectiveness of thawing and rewarming cryopreserved islets in a hyperoxic environment. Following cryopreservation of isolated human islets, the thawing solution and culture media were prepared with or without pre-equilibration to 50% oxygen. Thawing/rewarming and the pursuant two-day culture were performed with or without oxygenation. Short-term recovery rate, defined as the volume change during cryopreservation and thawing/rewarming, was assessed. Ischemia-associated and inflammation-associated gene expressions were examined using qPCR after the initial rewarming period. Long-term recovery rate, defined as the volume change during the two-day culture after the thawing/rewarming, was also examined. Islet metabolism and function were assessed by basal oxygen consumption rate and glucose stimulated insulin secretion after long-term recovery. Oxygenated thawing/rewarming did not alter the short-term recovery rate. Inflammation-associated gene expressions were elevated by the conventional thawing/rewarming method and suppressed by the oxygenated thawing/rewarming, whereas ischemia-associated gene expressions did not change between the thawing/rewarming methods. Long-term recovery rate experiments revealed that only the combination therapy of oxygenated thawing/rewarming and oxygenated culture alleviated islet volume loss. These islets showed higher metabolism

  13. Is islet transplantation a realistic approach to curing diabetes?

    Science.gov (United States)

    Jin, Sang-Man; Kim, Kwang-Won

    2017-01-01

    Since the report of type 1 diabetes reversal in seven consecutive patients by the Edmonton protocol in 2000, pancreatic islet transplantation has been reappraised based on accumulated clinical evidence. Although initially expected to therapeutically target long-term insulin independence, islet transplantation is now indicated for more specific clinical benefits. With the long-awaited report of the first phase 3 clinical trial in 2016, allogeneic islet transplantation is now transitioning from an experimental to a proven therapy for type 1 diabetes with problematic hypoglycemia. Islet autotransplantation has already been therapeutically proven in chronic pancreatitis with severe abdominal pain refractory to conventional treatments, and it holds promise for preventing diabetes after partial pancreatectomy due to benign pancreatic tumors. Based on current evidence, this review focuses on islet transplantation as a realistic approach to treating diabetes.

  14. Differentiation of insulin-producing cells from human neural progenitor cells.

    Directory of Open Access Journals (Sweden)

    Yuichi Hori

    2005-04-01

    Full Text Available BACKGROUND: Success in islet-transplantation-based therapies for type 1 diabetes, coupled with a worldwide shortage of transplant-ready islets, has motivated efforts to develop renewable sources of islet-replacement tissue. Islets and neurons share features, including common developmental programs, and in some species brain neurons are the principal source of systemic insulin. METHODS AND FINDINGS: Here we show that brain-derived human neural progenitor cells, exposed to a series of signals that regulate in vivo pancreatic islet development, form clusters of glucose-responsive insulin-producing cells (IPCs. During in vitro differentiation of neural progenitor cells with this novel method, genes encoding essential known in vivo regulators of pancreatic islet development were expressed. Following transplantation into immunocompromised mice, IPCs released insulin C-peptide upon glucose challenge, remained differentiated, and did not form detectable tumors. CONCLUSION: Production of IPCs solely through extracellular factor modulation in the absence of genetic manipulations may promote strategies to derive transplantable islet-replacement tissues from human neural progenitor cells and other types of multipotent human stem cells.

  15. Ionic and secretory response of pancreatic islet cells to minoxidil sulfate

    International Nuclear Information System (INIS)

    Antoine, M.H.; Hermann, M.; Herchuelz, A.; Lebrun, P.

    1991-01-01

    Minoxidil sulfate is an antihypertensive agent belonging to the new class of vasodilators, the K+ channel openers. The present study was undertaken to characterize the effects of minoxidil sulfate on ionic and secretory events in rat pancreatic islets. The drug unexpectedly provoked a concentration-dependent decrease in 86Rb outflow. This inhibitory effect was reduced in a concentration-dependent manner by glucose and tolbutamide. Minoxidil sulfate did not affect 45Ca outflow from islets perfused in the presence of extracellular Ca++ and absence or presence of glucose. However, in islets exposed to a medium deprived of extracellular Ca++, the drug provoked a rise in 45Ca outflow. Whether in the absence or presence of extracellular Ca++, minoxidil sulfate increased the cytosolic free Ca++ concentration of islet cells. Lastly, minoxidil sulfate increased the release of insulin from glucose-stimulated pancreatic islets. These results suggest that minoxidil sulfate reduces the activity of the ATP-sensitive K+ channels and promotes an intracellular translocation of Ca++. The latter change might account for the effect of the drug on the insulin-releasing process. However, the secretory response to minoxidil sulfate could also be mediated, at least in part, by a modest Ca++ entry

  16. Update on Islet Transplantation

    Science.gov (United States)

    McCall, Michael; James Shapiro, A.M.

    2012-01-01

    Clinical islet transplantation has progressed considerably over the past 12 years, and >750 patients with type 1 diabetes have received islet transplants internationally over this time. Many countries are beginning to accept the transition from research to accepted and funded clinical care, especially for patients with brittle control that cannot be stabilized by more conventional means. Major challenges remain, including the need for more than one donor, and the requirement for potent, chronic immunosuppression. Combining immunological tolerance both to allo- and autoantigens, and a limitless expandable source of stem cell- or xenograft-derived insulin-secreting cells represent remaining hurdles in moving this effective treatment to a potential cure for all those with type 1 or 2 diabetes. PMID:22762022

  17. Biotin uptake by mouse and human pancreatic beta cells/islets: a regulated, lipopolysaccharide-sensitive carrier-mediated process

    Science.gov (United States)

    Ghosal, Abhisek; Sekar, Thillai V.

    2014-01-01

    Biotin is essential for the normal function of pancreatic beta cells. These cells obtain biotin from their surroundings via transport across their cell membrane. Little is known about the uptake mechanism involved, how it is regulated, and how it is affected by internal and external factors. We addressed these issues using the mouse-derived pancreatic beta-TC-6 cells and freshly isolated mouse and human primary pancreatic beta cells as models. The results showed biotin uptake by pancreatic beta-TC-6 cells occurs via a Na+-dependent, carrier-mediated process, that is sensitive to desthiobiotin, as well as to pantothenic acid and lipoate; the process is also saturable as a function of concentration (apparent Km = 22.24 ± 5.5 μM). These cells express the sodium-dependent multivitamin transporter (SMVT), whose knockdown (with doxycycline-inducible shRNA) led to a sever inhibition in biotin uptake. Similarly, uptake of biotin by mouse and human primary pancreatic islets is Na+-dependent and carrier-mediated, and both cell types express SMVT. Biotin uptake by pancreatic beta-TC-6 cells is also adaptively regulated (via transcriptional mechanism) by extracellular substrate level. Chronic treatment of pancreatic beta-TC-6 cells with bacterial lipopolysaccharides (LPS) leads to inhibition in biotin uptake. This inhibition is mediated via a Toll-Like receptor 4-mediated process and involves a decrease in membrane expression of SMVT. These findings show, for the first time, that pancreatic beta cells/islets take up biotin via a specific and regulated carrier-mediated process, and that the process is sensitive to the effect of LPS. PMID:24904078

  18. Enhancing engraftment of islets using perioperative sodium 4-phenylbutyrate.

    Science.gov (United States)

    Hsu, Brend Ray-Sea; Chen, Szu-Tah; Fu, Shin-Huei

    2006-12-20

    Primary nonfunction (PNF) adversely impacts islet transplantation. In addition to determining whether sodium 4-phenylbutyrate (4-SPB), an anti-inflammatory agent, reduces PNF, this study investigates how 4-SPB affects PNF. Streptozotocin-induced diabetic C57BL/6 mice, that received 75 syngeneic islets underneath left subrenal space, were fed twice daily of either 4-SPB at 500 mg/kg body weight or isotonic saline (NaCl) from 2 days before through 7 days after transplantation. The graft was removed at days 3, 10 and 84 following transplantation. At 68 h following transplantation, serum levels of interleukin-1beta (IL-1beta) were 2.2+/-0.4 and 0.4+/-0.2 pmol/L (n=6, p<0.005) for NaCl and 4-SPB groups, respectively. Graft genetic expression of IL-1beta was significantly suppressed in 4-SPB group (p<0.01). At day 10, the blood glucose levels were 22.7+/-1.0 and 17.1+/-1.7 mmol/L (n=12, p<0.05) and graft insulin contents (IC) were 35.0+/-8.3 and 107.6+/-29.7 pmol (n=12, p<0.05) for NaCl and 4-SPB groups, respectively. Moreover, the 4-SPB group had a shorter temporary hyperglycemia (15+/-2, n=21 vs. 25+/-2 days, n=19, p=0.001) and a higher cumulative cure rate of diabetes (p<0.001) than the NaCl group. In-vitro studies indicated that 4-SPB did not impact the islets function. These experimental results demonstrated that perioperative administration of 4-SPB decreased serum level and graft genetic expression of IL-1beta and attenuated PNF, which enhanced islet engraftment in a syngeneic transplantation mouse model.

  19. Glucose metabolism in pigs expressing human genes under an insulin promoter.

    Science.gov (United States)

    Wijkstrom, Martin; Bottino, Rita; Iwase, Hayoto; Hara, Hidetaka; Ekser, Burcin; van der Windt, Dirk; Long, Cassandra; Toledo, Frederico G S; Phelps, Carol J; Trucco, Massimo; Cooper, David K C; Ayares, David

    2015-01-01

    Xenotransplantation of porcine islets can reverse diabetes in non-human primates. The remaining hurdles for clinical application include safe and effective T-cell-directed immunosuppression, but protection against the innate immune system and coagulation dysfunction may be more difficult to achieve. Islet-targeted genetic manipulation of islet-source pigs represents a powerful tool to protect against graft loss. However, whether these genetic alterations would impair islet function is unknown. On a background of α1,3-galactosyltransferase gene-knockout (GTKO)/human (h)CD46, additional genes (hCD39, human tissue factor pathway inhibitor, porcine CTLA4-Ig) were inserted in different combinations under an insulin promoter to promote expression in islets (confirmed by immunofluorescence). Seven pigs were tested for baseline and glucose/arginine-challenged levels of glucose, insulin, C-peptide, and glucagon. This preliminary study did not show definite evidence of β-cell deficiencies, even when three transgenes were expressed under the insulin promoter. Of seven animals, all were normoglycemic at fasting, and five of seven had normal glucose disposal rates after challenge. All animals exhibited insulin, C-peptide, and glucagon responses to both glucose and arginine challenge; however, significant interindividual variation was observed. Multiple islet-targeted transgenic expression was not associated with an overtly detrimental effect on islet function, suggesting that complex genetic constructs designed for islet protection warrants further testing in islet xenotransplantation models. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Pancreatic islet allograft in spleen with immunosuppression with cyclosporine. Experimental model in dogs.

    Science.gov (United States)

    Waisberg, Jaques; Neff, Charles Benjamin; Waisberg, Daniel Reis; Germini, Demetrius; Gonçalves, José Eduardo; Zanotto, Arnaldo; Speranzini, Manlio Basilio

    2011-01-01

    To study the functional behavior of the allograft with immunosuppression of pancreatic islets in the spleen. Five groups of 10 Mongrel dogs were used: Group A (control) underwent biochemical tests; Group B underwent total pancreatectomy; Group C underwent total pancreatectomy and pancreatic islet autotransplant in the spleen; Group D underwent pancreatic islet allograft in the spleen without immunosuppressive therapy; Group E underwent pancreatic islet allograft in the spleen and immunosuppression with cyclosporine. All of the animals with grafts received pancreatic islets prepared by the mechanical-enzymatic method - stationary collagenase digestion and purification with dextran discontinuous density gradient, implanted in the spleen. The animals with autotransplant and those with allografts with immunosuppression that became normoglycemic showed altered results of intravenous tolerance glucose (p < 0.001) and peripheral and splenic vein plasmatic insulin levels were significantly lower (p < 0.001) in animals that had allografts with immunosuppression than in those with just autotransplants. In the animals with immunosuppression with cyclosporine subjected to allograft of pancreatic islets prepared with the mechanical-enzymatic preparation method (stationary collagenase digestion and purification with dextran discontinuous density gradient), the production of insulin is decreased and the response to intravenous glucose is altered.

  1. Alterations of pancreatic islet structure, metabolism and gene expression in diet-induced obese C57BL/6J mice.

    Directory of Open Access Journals (Sweden)

    Regan Roat

    Full Text Available The reduction of functional β cell mass is a key feature of type 2 diabetes. Here, we studied metabolic functions and islet gene expression profiles of C57BL/6J mice with naturally occurring nicotinamide nucleotide transhydrogenase (NNT deletion mutation, a widely used model of diet-induced obesity and diabetes. On high fat diet (HF, the mice developed obesity and hyperinsulinemia, while blood glucose levels were only mildly elevated indicating a substantial capacity to compensate for insulin resistance. The basal serum insulin levels were elevated in HF mice, but insulin secretion in response to glucose load was significantly blunted. Hyperinsulinemia in HF fed mice was associated with an increase in islet mass and size along with higher BrdU incorporation to β cells. The temporal profiles of glucose-stimulated insulin secretion (GSIS of isolated islets were comparable in HF and normal chow fed mice. Islets isolated from HF fed mice had elevated basal oxygen consumption per islet but failed to increase oxygen consumption further in response to glucose or carbonyl cyanide-4-trifluoromethoxyphenylhydrazone (FCCP. To obtain an unbiased assessment of metabolic pathways in islets, we performed microarray analysis comparing gene expression in islets from HF to normal chow-fed mice. A few genes, for example, those genes involved in the protection against oxidative stress (hypoxia upregulated protein 1 and Pgc1α were up-regulated in HF islets. In contrast, several genes in extracellular matrix and other pathways were suppressed in HF islets. These results indicate that islets from C57BL/6J mice with NNT deletion mutation develop structural, metabolic and gene expression features consistent with compensation and decompensation in response to HF diet.

  2. Ketosis Onset Type 2 Diabetes Had Better Islet β-Cell Function and More Serious Insulin Resistance

    Science.gov (United States)

    Lu, Hongyun; Hu, Fang; Zeng, Yingjuan; Zou, Lingling; Luo, Shunkui; Sun, Ying; Liu, Hong; Sun, Liao

    2014-01-01

    Diabetic ketosis had been identified as a characteristic of type 1 diabetes mellitus (T1DM), but now emerging evidence has identified that they were diagnosed as T2DM after long time follow up. This case control study was aimed at comparing the clinical characteristic, β-cell function, and insulin resistance of ketosis and nonketotic onset T2DM and providing evidence for treatment selection. 140 cases of newly diagnosed T2DM patients were divided into ketosis (62 cases) and nonketotic onset group (78 cases). After correction of hyperglycemia and ketosis with insulin therapy, plasma C-peptide concentrations were measured at 0, 0.5, 1, 2, and 3 hours after 75 g glucose oral administration. Area under the curve (AUC) of C-peptide was calculated. Homoeostasis model assessment was used to estimate basal β-cell function (HOMA-β) and insulin resistance (HOMA-IR). Our results showed that ketosis onset group had higher prevalence of nonalcoholic fatty liver disease (NAFLD) than nonketotic group (P = 0.04). Ketosis onset group had increased plasma C-peptide levels at 0 h, 0.5 h, and 3 h and higher AUC0–0.5, AUC0–1, AUC0–3 (P ketosis onset T2DM had better islet β-cell function and more serious insulin resistance than nonketotic onset T2DM. PMID:24829925

  3. Morphological assessment of pancreatic islet hormone content following aerobic exercise training in rats with poorly controlled Type 1 diabetes mellitus.

    Science.gov (United States)

    McDonald, Matthew W; Murray, Michael R; Hall, Katharine E; Noble, Earl G; Melling, C W James

    2014-01-01

    Regular exercise has been shown to improve many complications of Type 1 diabetes mellitus (T1DM) including enhanced glucose tolerance and increased cardiac function. While exercise training has been shown to increase insulin content in pancreatic islets of rats with T1DM, experimental models were severely hyperglycemic and not undergoing insulin treatment. Further, research to date has yet to determine how exercise training alters glucagon content in pancreatic islets. The purpose of the present investigation was to determine the impact of a 10-week aerobic training program on pancreatic islet composition in insulin-treated rats with T1DM. Second, it was determined whether the acute, exercise-mediated reduction in blood glucose experienced in rats with T1DM would become larger in magnitude following aerobic exercise training. Diabetes was induced in male Sprague-Dawley rats by multiple low dose injections of streptozotocin (20mg/kg i.p.) and moderate intensity aerobic exercise training was performed on a motorized treadmill for one hour per day for a total of 10 weeks. Rats with T1DM demonstrated significantly less islet insulin, and significantly more islet glucagon hormone content compared with non-T1DM rats, which did not significantly change following aerobic training. The reduction in blood glucose in response to a single exercise bout was similar across 10 weeks of training. Results also support the view that different subpopulations of islets exist, as small islets (<50 μm diameter) had significantly more insulin and glucagon in rats with and without T1DM.

  4. Localized modulated wave solutions in diffusive glucose–insulin systems

    Energy Technology Data Exchange (ETDEWEB)

    Mvogo, Alain, E-mail: mvogal_2009@yahoo.fr [Laboratory of Biophysics, Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, University of Yaounde (Cameroon); Centre d' Excellence Africain en Technologies de l' Information et de la Communication, University of Yaounde I (Cameroon); Tambue, Antoine [The African Institute for Mathematical Sciences (AIMS) and Stellenbosch University, 6-8 Melrose Road, Muizenberg 7945 (South Africa); Center for Research in Computational and Applied Mechanics (CERECAM), and Department of Mathematics and Applied Mathematics, University of Cape Town, 7701 Rondebosch (South Africa); Ben-Bolie, Germain H. [Centre d' Excellence Africain en Technologies de l' Information et de la Communication, University of Yaounde I (Cameroon); Laboratory of Nuclear Physics, Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, University of Yaounde (Cameroon); Kofané, Timoléon C. [Centre d' Excellence Africain en Technologies de l' Information et de la Communication, University of Yaounde I (Cameroon); Laboratory of Mechanics, Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, University of Yaounde (Cameroon)

    2016-06-03

    We investigate intercellular insulin dynamics in an array of diffusively coupled pancreatic islet β-cells. The cells are connected via gap junction coupling, where nearest neighbor interactions are included. Through the multiple scale expansion in the semi-discrete approximation, we show that the insulin dynamics can be governed by the complex Ginzburg–Landau equation. The localized solutions of this equation are reported. The results suggest from the biophysical point of view that the insulin propagates in pancreatic islet β-cells using both temporal and spatial dimensions in the form of localized modulated waves. - Highlights: • The dynamics of an array of diffusively coupled pancreatic islet beta-cells is investigated. • Through the multiple scale expansion, we show that the insulin dynamics can be governed by the complex Ginzburg–Landau equation. • Localized modulated waves are obtained for the insulin dynamics.

  5. Autologous Pancreatic Islet Transplantation in Human Bone Marrow

    Science.gov (United States)

    Maffi, Paola; Balzano, Gianpaolo; Ponzoni, Maurilio; Nano, Rita; Sordi, Valeria; Melzi, Raffaella; Mercalli, Alessia; Scavini, Marina; Esposito, Antonio; Peccatori, Jacopo; Cantarelli, Elisa; Messina, Carlo; Bernardi, Massimo; Del Maschio, Alessandro; Staudacher, Carlo; Doglioni, Claudio; Ciceri, Fabio; Secchi, Antonio; Piemonti, Lorenzo

    2013-01-01

    The liver is the current site of choice for pancreatic islet transplantation, even though it is far from being ideal. We recently have shown in mice that the bone marrow (BM) may be a valid alternative to the liver, and here we report a pilot study to test feasibility and safety of BM as a site for islet transplantation in humans. Four patients who developed diabetes after total pancreatectomy were candidates for the autologous transplantation of pancreatic islet. Because the patients had contraindications for intraportal infusion, islets were infused in the BM. In all recipients, islets engrafted successfully as shown by measurable posttransplantation C-peptide levels and histopathological evidence of insulin-producing cells or molecular markers of endocrine tissue in BM biopsy samples analyzed during follow-up. Thus far, we have recorded no adverse events related to the infusion procedure or the presence of islets in the BM. Islet function was sustained for the maximum follow-up of 944 days. The encouraging results of this pilot study provide new perspectives in identifying alternative sites for islet infusion in patients with type 1 diabetes. Moreover, this is the first unequivocal example of successful engraftment of endocrine tissue in the BM in humans. PMID:23733196

  6. SAD-A potentiates glucose-stimulated insulin secretion as a mediator of glucagon-like peptide 1 response in pancreatic β cells.

    Science.gov (United States)

    Nie, Jia; Lilley, Brendan N; Pan, Y Albert; Faruque, Omar; Liu, Xiaolei; Zhang, Weiping; Sanes, Joshua R; Han, Xiao; Shi, Yuguang

    2013-07-01

    Type 2 diabetes is characterized by defective glucose-stimulated insulin secretion (GSIS) from pancreatic β cells, which can be restored by glucagon-like peptide 1 (GLP-1), an incretin hormone commonly used for the treatment of type 2 diabetes. However, molecular mechanisms by which GLP-1 affects glucose responsiveness in islet β cells remain poorly understood. Here we investigated a role of SAD-A, an AMP-activated protein kinase (AMPK)-related kinase, in regulating GSIS in mice with conditional SAD-A deletion. We show that selective deletion of SAD-A in pancreas impaired incretin's effect on GSIS, leading to glucose intolerance. Conversely, overexpression of SAD-A significantly enhanced GSIS and further potentiated GLP-1's effect on GSIS from isolated mouse islets. In support of SAD-A as a mediator of incretin response, SAD-A is expressed exclusively in pancreas and brain, the primary targeting tissues of GLP-1 action. Additionally, SAD-A kinase is activated in response to stimulation by GLP-1 through cyclic AMP (cAMP)/Ca(2+)-dependent signaling pathways in islet β cells. Furthermore, we identified Thr443 as a key autoinhibitory phosphorylation site which mediates SAD-A's effect on incretin response in islet β cells. Consequently, ablation of Thr443 significantly enhanced GLP-1's effect on GSIS from isolated mouse islets. Together, these findings identified SAD-A kinase as a pancreas-specific mediator of incretin response in islet β cells.

  7. Islet amyloid polypeptide and high hydrostatic pressure: towards an understanding of the fibrillization process

    Science.gov (United States)

    Lopes, D. H. J.; Smirnovas, V.; Winter, R.

    2008-07-01

    Type II Diabetes Mellitus is a disease which is characterized by peripheral insulin resistance coupled with a progressive loss of insulin secretion that is associated with a decrease in pancreatic islet β-cell mass and the deposition of amyloid in the extracellular matrix of β-cells, which lead to islet cell death. The principal component of the islet amyloid is a pancreatic hormone called islet amyloid polypeptide (IAPP). High-pressure coupled with FT-IR, CD, ThT fluorescence spectroscopic and AFM studies were carried out to reveal information on the aggregation pathway as well as the aggregate structure of IAPP. Our data indicate that IAPP pre-formed fibrils exhibit a strong polymorphism with heterogeneous structures very sensitive to high hydrostatic pressure, indicating a high percentage of ionic and hydrophobic interactions being responsible for the stability the IAPP fibrils.

  8. The L-alpha-amino acid receptor GPRC6A is expressed in the islets of Langerhans but is not involved in L-arginine-induced insulin release

    DEFF Research Database (Denmark)

    Smajilovic, Sanela; Clemmensen, Christoffer; Johansen, Lars Dan

    2013-01-01

    insulin secretion; therefore, the receptor has been hypothesized to have a role in regulating glucose metabolism. In this study, we demonstrate that GPRC6A is expressed in islets of Langerhans, but activation of the receptor by L-arginine did not stimulate insulin secretion. We also investigated central...... metabolic parameters in GPRC6A knockout mice compared with wildtype littermates and found no difference in glucose metabolism or body fat percentage when mice were administered a standard chow diet. In conclusion, our data do not support a role for GPRC6A in L-arginine-induced insulin release and glucose...

  9. A role for SPARC in the moderation of human insulin secretion.

    Directory of Open Access Journals (Sweden)

    Lorna W Harries

    Full Text Available AIMS/HYPOTHESIS: We have previously shown the implication of the multifunctional protein SPARC (Secreted protein acidic and rich in cysteine/osteonectin in insulin resistance but potential effects on beta-cell function have not been assessed. We therefore aimed to characterise the effect of SPARC on beta-cell function and features of diabetes. METHODS: We measured SPARC expression by qRT-PCR in human primary pancreatic islets, adipose tissue, liver and muscle. We then examined the relation of SPARC with glucose stimulated insulin secretion (GSIS in primary human islets and the effect of SPARC overexpression on GSIS in beta cell lines. RESULTS: SPARC was expressed at measurable levels in human islets, adipose tissue, liver and skeletal muscle, and demonstrated reduced expression in primary islets from subjects with diabetes compared with controls (p< = 0.05. SPARC levels were positively correlated with GSIS in islets from control donors (p< = 0.01. Overexpression of SPARC in cultured beta-cells resulted in a 2.4-fold increase in insulin secretion in high glucose conditions (p< = 0.01. CONCLUSIONS: Our data suggest that levels of SPARC are reduced in islets from donors with diabetes and that it has a role in insulin secretion, an effect which appears independent of SPARC's modulation of obesity-induced insulin resistance in adipose tissue.

  10. Entrapment of dispersed pancreatic islet cells in CultiSpher-S macroporous gelatin microcarriers: Preparation, in vitro characterization, and microencapsulation.

    Science.gov (United States)

    Del Guerra, S; Bracci, C; Nilsson, K; Belcourt, A; Kessler, L; Lupi, R; Marselli, L; De Vos, P; Marchetti, P

    2001-12-20

    Immunoprotection of pancreatic islets for successful allo- or xenotransplantation without chronic immunosuppression is an attractive, but still elusive, approach for curing type 1 diabetes. It was recently shown that, even in the absence of fibrotic overgrowth, other factors, mainly insufficient nutrition to the core of the islets, represent a major barrier for long-term survival of intraperitoneal microencapsulated islet grafts. The use of dispersed cells might contribute to solve this problem due to the conceivably easier nutritional support to the cells. In the present study, purified bovine islets, prepared by collagenase digestion and density gradient purification, and dispersed bovine islet cells, obtained by trypsin and DNAsi (viability > 90%), were entrapped into either 2% (w/v) sodium alginate (commonly used for encapsulation purposes) or (dispersed islet cells only) macroporous gelatin microcarriers (CulthiSpher-S, commonly used for the production of biologicals by animal cells). Insulin release studies in response to glucose were performed within 1 week and after 1 month from preparation of the varying systems and showed no capability of dispersed bovine islet cells within sodium alginate microcapsules to sense glucose concentration changes. On the contrary, bovine islet cells entrapped in CulthiSpher-S microcarriers showed maintained capacity of increasing insulin secretion upon enhanced glucose concentration challenge. In this case, insulin release was approximately 60% of that from intact bovine islets within sodium alginate microcapsules. MTT and hematoxylineosin staining of islet cell-containing microcarriers showed the presence of viable and metabolically active cells throughout the study period. This encouraging functional data prompted us to test whether the microcarriers could be immunoisolated for potential use in transplantation. The microcarriers were embedded within 3% sodium alginate, which was then covered with a poly-L-lysine layer and a

  11. Possible contribution of taurine to distorted glucagon secretion in intra-islet insulin deficiency: a metabolome analysis using a novel α-cell model of insulin-deficient diabetes.

    Directory of Open Access Journals (Sweden)

    Megumi Bessho

    Full Text Available Glycemic instability is a serious problem in patients with insulin-deficient diabetes, and it may be due in part to abnormal endogenous glucagon secretion. However, the intracellular metabolic mechanism(s involved in the aberrant glucagon response under the condition of insulin deficiency has not yet been elucidated. To investigate the metabolic traits that underlie the distortion of glucagon secretion under insulin deficient conditions, we generated an αTC1-6 cell line with stable knockdown of the insulin receptor (IRKD, i.e., an in vitro α-cell model for insulin-deficient diabetes, which exhibits an abnormal glucagon response to glucose. A comprehensive metabolomic analysis of the IRKD αTC1-6 cells (IRKD cells revealed some candidate metabolites whose levels differed markedly compared to those in control αTC1-6 cells, but also which could affect the glucagon release in IRKD cells. Of these candidates, taurine was remarkably increased in the IRKD cells and was identified as a stimulator of glucagon in αTC1-6 cells. Taurine also paradoxically exaggerated the glucagon secretion at a high glucose concentration in IRKD cells and islets with IRKD. These results indicate that the metabolic alterations induced by IRKD in α-cells, especially the increase of taurine, may lead to the distorted glucagon response in IRKD cells, suggesting the importance of taurine in the paradoxical glucagon response and the resultant glucose instability in insulin-deficient diabetes.

  12. Excessive islet NO generation in type 2 diabetic GK rats coincides with abnormal hormone secretion and is counteracted by GLP-1.

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    Albert Salehi

    Full Text Available BACKGROUND: A distinctive feature of type 2 diabetes is inability of insulin-secreting beta-cells to properly respond to elevated glucose eventually leading to beta-cell failure. We have hypothesized that an abnormally increased NO production in the pancreatic islets might be an important factor in the pathogenesis of beta-cell dysfunction. PRINCIPAL FINDINGS: We show now that islets of type 2 spontaneous diabetes in GK rats display excessive NO generation associated with abnormal iNOS expression in insulin and glucagon cells, increased ncNOS activity, impaired glucose-stimulated insulin release, glucagon hypersecretion, and impaired glucose-induced glucagon suppression. Pharmacological blockade of islet NO production by the NOS inhibitor N(G-nitro-L-arginine methyl ester (L-NAME greatly improved hormone secretion from GK islets suggesting islet NOS activity being an important target to inactivate for amelioration of islet cell function. The incretin hormone GLP-1, which is used in clinical practice suppressed iNOS and ncNOS expression and activity with almost full restoration of insulin release and partial restoration of glucagon release. GLP-1 suppression of iNOS expression was reversed by PKA inhibition but unaffected by the proteasome inhibitor MG132. Injection of glucose plus GLP-1 in the diabetic rats showed that GLP-1 amplified the insulin response but induced a transient increase and then a poor depression of glucagon. CONCLUSION: The results suggest that abnormally increased NO production within islet cells is a significant player in the pathogenesis of type 2 diabetes being counteracted by GLP-1 through PKA-dependent, nonproteasomal mechanisms.

  13. Beneficial effect of 17β-estradiol on hyperglycemia and islet β-cell functions in a streptozotocin-induced diabetic rat model

    International Nuclear Information System (INIS)

    Yamabe, Noriko; Kang, Ki Sung; Zhu Baoting

    2010-01-01

    The modulating effect of estrogen on glucose homeostasis remains a controversial issue at present. In this study, we sought to determine the beneficial effect of 17β-estradiol (E 2 ) on hyperglycemia and islet β-cell functions in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were injected i.p. with STZ to induce a relatively mild diabetic condition. The rats were then treated with E 2 orally at 500 μg/kg body weight/day for 15 days to evaluate the modulating effect on hyperglycemia, insulin secretion, and islet β-cell proliferation. E 2 administration for 10 days significantly lowered plasma glucose levels, increased plasma insulin levels, and improved glucose tolerance by attenuating insulin response to oral glucose loading. These beneficial effects of E 2 were accompanied by increases in islet number and volume, rate of islet cell proliferation, and the amount of insulin secreted. The growth-stimulatory effect of E 2 on islet cells was linked to the functions of the estrogen receptor α. Notably, these protective effects of E 2 on diabetic conditions were basically not observed when the STZ-treated rats had a more severe degree of islet damage and hyperglycemia. Taken together, we conclude that E 2 can promote the regeneration of damaged pancreatic islets by stimulating β-cell proliferation in diabetic rats, and this effect is accompanied by improvements in glucose tolerance and a decrease in plasma glucose levels. These findings suggest that oral administration of E 2 may be beneficial in diabetic patients with an accelerated loss of islet β-cells.

  14. Total pancreatectomy and islet autotransplantation for chronic pancreatitis.

    Science.gov (United States)

    Sutherland, David E R; Radosevich, David M; Bellin, Melena D; Hering, Bernard J; Beilman, Gregory J; Dunn, Ty B; Chinnakotla, Srinath; Vickers, Selwyn M; Bland, Barbara; Balamurugan, A N; Freeman, Martin L; Pruett, Timothy L

    2012-04-01

    Total pancreatectomy (TP) with intraportal islet autotransplantation (IAT) can relieve pain and preserve β-cell mass in patients with chronic pancreatitis (CP) when other therapies fail. We report on a >30-year single-center series. Four hundred and nine patients (including 53 children, 5 to 18 years) with CP underwent TP-IAT from February 1977 to September 2011 (etiology: idiopathic, 41%; Sphincter of Oddi dysfunction/biliary, 9%; genetic, 14%; divisum, 17%; alcohol, 7%; and other, 12%; mean age was 35.3 years, 74% were female; 21% has earlier operations, including 9% Puestow procedure, 6% Whipple, 7% distal pancreatectomy, and 2% other). Islet function was classified as insulin independent for those on no insulin; partial, if known C-peptide positive or euglycemic on once-daily insulin; and insulin dependent if on standard basal-bolus diabetic regimen. A 36-item Short Form (SF-36) survey for quality of life was completed by patients before and in serial follow-up since 2007, with an integrated survey that was added in 2008. Actuarial patient survival post TP-IAT was 96% in adults and 98% in children (1 year) and 89% and 98% (5 years). Complications requiring relaparotomy occurred in 15.9% and bleeding (9.5%) was the most common complication. IAT function was achieved in 90% (C-peptide >0.6 ng/mL). At 3 years, 30% were insulin independent (25% in adults, 55% in children) and 33% had partial function. Mean hemoglobin A1c was 5,000/kg [24%]) correlated with degree of function with insulin-independent rates at 3 years of 12%, 22%, and 72%, and rates of partial function 33%, 62%, and 24%. All patients had pain before TP-IAT and nearly all were on daily narcotics. After TP-IAT, 85% had pain improvement. By 2 years, 59% had ceased narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; and 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions, including the Physical and Mental

  15. Treatment of diabetic rats with encapsulated islets.

    Science.gov (United States)

    Sweet, Ian R; Yanay, Ofer; Waldron, Lanaya; Gilbert, Merle; Fuller, Jessica M; Tupling, Terry; Lernmark, Ake; Osborne, William R A

    2008-12-01

    Immunoprotection of islets using bioisolator systems permits introduction of allogeneic cells to diabetic patients without the need for immunosuppression. Using TheraCyte immunoisolation devices, we investigated two rat models of type 1 diabetes mellitus (T1DM), BB rats and rats made diabetic by streptozotocin (STZ) treatment. We chose to implant islets after the onset of diabetes to mimic the probable treatment of children with T1DM as they are usually diagnosed after disease onset. We encapsulated 1000 rat islets and implanted them subcutaneously (SQ) into diabetic biobreeding (BB) rats and STZ-induced diabetic rats, defined as two or more consecutive days of blood glucose>350 mg/dl. Rats were monitored for weight and blood glucose. Untreated BB rats rapidly lost weight and were euthanized at >20% weight loss that occurred between 4 and 10 days from implantation. For period of 30-40 days following islet implantation weights of treated rats remained steady or increased. Rapid weight loss occurred after surgical removal of devices that contained insulin positive islets. STZ-treated rats that received encapsulated islets showed steady weight gain for up to 130 days, whereas untreated control rats showed steady weight loss that achieved >20% at around 55 days. Although islet implants did not normalize blood glucose, treated rats were apparently healthy and groomed normally. Autologous or allogeneic islets were equally effective in providing treatment. TheraCyte devices can sustain islets, protect allogeneic cells from immune attack and provide treatment for diabetic-mediated weight loss in both BB rats and STZ-induced diabetic rats.

  16. Entrapment of cultured pancreas islets in three-dimensional collagen matrices.

    Science.gov (United States)

    Chao, S H; Peshwa, M V; Sutherland, D E; Hu, W S

    1992-01-01

    In vitro culture of islets of Langerhans decreases their immunogenicity, presumably by eliminating passenger leukocytes and other Ia+ presenting cells within the islets. Islets cultivated in petri dishes either at 37 degrees C or at 25 degrees C gradually disintegrate during culture in a time-dependent manner which is related to the free-floating condition of the islets. Also, a fraction of the islets disperse as single cells and beta-cell aggregates or adhere to the bottom of the culture dishes. Thus, the retrieval rate of transplantable islets is dampened due to their disintegration and spontaneous dispersion in conventional petri dish cultures. Entrapment of freshly harvested islets of Langerhans in a three-dimensional collagen matrix was studied as an alternative method for islet cultivation. The contraction of collagen fibrils during in vitro culture counteracts the dispersion of islets and helps in maintaining their integrity while in culture. It was observed that the entrapped islets maintain satisfactory morphology, viability, and capability of glucose-dependent insulin secretion for over 2 wk. The oxygen consumption rate and glucose metabolism of these islets was not deranged when entrapped in collagen. Also, the retrieval of islets is easier and more efficient than that observed in conventional culture systems. Our results indicate that culture of islets in three-dimensional collagen gels can potentially develop into an ideal system applicable to clinical transplantation of cultured islets or beta-cell aggregates.

  17. Design of bioartificial pancreas with functional micro/nano-based encapsulation of islets.

    Science.gov (United States)

    Kepsutlu, Burcu; Nazli, Caner; Bal, Tugba; Kizilel, Seda

    2014-01-01

    Type I diabetes mellitus (TIDM), a devastating health issue in all over the world, has been treated by successful transplantation of insulin secreting pancreatic islets. However, serious limitations such as the requirement of immunosuppressive drugs for recipient patients, side effects as a result of long-term use of drugs, and reduced functionality of islets at the transplantation site remain. Bioartificial pancreas that includes islets encapsulated within semi-permeable membrane has been considered as a promising approach to address these requirements. Many studies have focused on micro or nanobased islet immunoisolation systems and tested the efficacy of encapsulated islets using in vitro and in vivo platforms. In this review, we address current progress and obstacles for the development of a bioartificial pancreas using micro/nanobased systems for encapsulation of islets.

  18. Differentiation of human multipotent dermal fibroblasts into islet-like cell clusters

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    Liu Wei

    2010-06-01

    Full Text Available Abstract Background We have previously obtained a clonal population of cells from human foreskin that is able to differentiate into mesodermal, ectodermal and endodermal progenies. It is of great interest to know whether these cells could be further differentiated into functional insulin-producing cells. Results Sixty-one single-cell-derived dermal fibroblast clones were established from human foreskin by limiting dilution culture. Of these, two clones could be differentiated into neuron-, adipocyte- or hepatocyte-like cells under certain culture conditions. In addition, those two clones were able to differentiate into islet-like clusters under pancreatic induction. Insulin, glucagon and somatostatin were detectable at the mRNA and protein levels after induction. Moreover, the islet-like clusters could release insulin in response to glucose in vitro. Conclusions This is the first study to demonstrate that dermal fibroblasts can differentiate into insulin-producing cells without genetic manipulation. This may offer a safer cell source for future stem cell-based therapies.

  19. Role of transglutaminase in insulin release. Study with glycine and sarcosine methylesters

    International Nuclear Information System (INIS)

    Sener, A.; Dunlop, M.E.; Gomis, R.; Mathias, P.C.; Malaisse-Lagae, F.; Malaisse, W.J.

    1985-01-01

    The Ca2+-responsive enzyme transglutaminase, which catalyzes the cross-bridging of proteins, is present in pancreatic islet cells, but its participation in the process of insulin release remains to be documented. Glycine methylester (1.0-10.0 mM) inhibited, in a dose-related manner, transglutaminase activity in rat pancreatic islet homogenates, decreased [ 14 C]methylamine incorporation into endogenous proteins of intact islets, and caused a rapid and reversible inhibition of insulin release evoked by D-glucose, while failing to affect D-[U- 14 C]glucose oxidation. Glycine methylester also inhibited insulin release induced by other nutrient or nonnutrient secretagogues. Sarcosine methylester failed to affect transglutaminase activity, [ 14 C]methylamine incorporation, and insulin release. Both methylesters mobilized 45 Ca from prelabeled intact islets, from membranes of islet cells, liver or brain, and from artificial lipid multilayers, this Ca mobilization being apparently unrelated to changes in transglutaminase activity. It is proposed that, in the pancreatic B cell, transglutaminase participates in the machinery controlling the access of secretory granules to the exocytotic sites

  20. FEATURES OF ISLET-LIKE CLUSTERS GENERATION IN PANCREATIC DUCTAL CELL MOLOLAYER CULTURING

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    L. A. Kirsanova

    2012-01-01

    Full Text Available Newborn rabbit pancreatic cell monolayer was obtained as we described earlier.The cultivated epithelial cells were shown by immunofluorescence to express special ductal marker CK19 and were insulin-and glucagon- negative for 10–15 days. A few fusiforms of nestin-positive cells were found in monolayer. Over 2 weeks in serum-free medium the plaques of epithelial cells became crowded and formed 3-dimentional structures – islet- like clusters. Islet-like clusters contain some insulin- and glucagon-positive cells recognized by immunohysto- chemistry staining. Pancreatic endocrine cell generation in 3-dimentional structures is discussed. 

  1. Gliadin Fragments and a Specific Gliadin 33-mer Peptide Close KATP Channels and Induce Insulin Secretion in INS-1E Cells and Rat Islets of Langerhans

    DEFF Research Database (Denmark)

    Dall, Morten; Calloe, Kirstine; Haupt-Jorgensen, Martin

    2013-01-01

    . A similar effect was observed in isolated rat islets (1.6-fold increase). In INS-1E cells, diazoxide reduced the stimulatory effect of gliadin digest. Additionally, gliadin digest was shown to decrease current through KATP-channels. A specific gliadin 33-mer had a similar effect, both on current and insulin...

  2. Aerobic exercise regulates blood lipid and insulin resistance via the toll‑like receptor 4‑mediated extracellular signal‑regulated kinases/AMP‑activated protein kinases signaling pathway.

    Science.gov (United States)

    Wang, Mei; Li, Sen; Wang, Fubaihui; Zou, Jinhui; Zhang, Yanfeng

    2018-06-01

    Diabetes mellitus is a complicated metabolic disease with symptoms of hyperglycemia, insulin resistance, chronic damage and dysfunction of tissues, and metabolic syndrome for insufficient insulin production. Evidence has indicated that exercise treatments are essential in the progression of type‑ІІ diabetes mellitus, and affect insulin resistance and activity of islet β‑cells. In the present study, the efficacy and signaling mechanism of aerobic exercise on blood lipids and insulin resistance were investigated in the progression of type‑ІІ diabetes mellitus. Body weight, glucose metabolism and insulin serum levels were investigated in mouse models of type‑ІІ diabetes mellitus following experienced aerobic exercise. Expression levels of inflammatory factors, interleukin (IL)‑6, high‑sensitivity C‑reactive protein, tumor necrosis factor‑α and leucocyte differentiation antigens, soluble CD40 ligand in the serum were analyzed in the experimental mice. In addition, expression levels of toll‑like receptor 4 (TLR‑4) were analyzed in the liver cells of experimental mice. Changes of oxidative stress indicators, including reactive oxygen species, superoxide dismutase, glutathione and catalase were examined in the liver cells of experimental mice treated by aerobic exercise. Expression levels and activity of extracellular signal‑regulated kinases (ERK) and AMP‑activated protein kinase (AMPK) signaling pathways were investigated in the liver cells of mouse models of type‑ІІ diabetes mellitus after undergoing aerobic exercise. Aerobic exercise decreased the expression levels of inflammatory factors in the serum of mouse models of type‑ІІ diabetes mellitus. The results indicated that aerobic exercise downregulated oxidative stress indicators in liver cells from mouse models of type‑ІІ diabetes mellitus. In addition, the ERK and AMPK signaling pathways were inactivated by aerobic exercise in liver cells in mouse models of type

  3. Insulin deficiency exacerbates cerebral amyloidosis and behavioral deficits in an Alzheimer transgenic mouse model

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    Teng Wei-Ping

    2010-11-01

    Full Text Available Abstract Background Although increasing evidence has indicated that brain insulin dysfunction is a risk factor for Alzheimer disease (AD, the underlying mechanisms by which insulin deficiency may impact the development of AD are still obscure. Using a streptozotocin (STZ-induced insulin deficient diabetic AD transgenic mouse model, we evaluated the effect of insulin deficiency on AD-like behavior and neuropathology. Results Our data showed that administration of STZ increased the level of blood glucose and reduced the level of serum insulin, and further decreased the phosphorylation levels of insulin receptors, and increased the activities of glycogen synthase kinase-3α/β and c-Jun N-terminal kinase in the APP/PS1 mouse brain. We further showed that STZ treatment promoted the processing of amyloid-β (Aβ precursor protein resulting in increased Aβ generation, neuritic plaque formation, and spatial memory deficits in transgenic mice. Conclusions Our present data indicate that there is a close link between insulin deficient diabetes and cerebral amyloidosis in the pathogenesis of AD.

  4. Functional and immunohistochemical evaluation of porcine neonatal islet-like cell clusters

    DEFF Research Database (Denmark)

    Nielsen, T B; Yderstraede, K B; Schrøder, H D

    2003-01-01

    Porcine neonatal islet-like cell clusters (NICCs) may be an attractive source of insulin-producing tissue for xenotransplantation in type I diabetic patients. We examined the functional and immunohistochemical outcome of the islet grafts in vitro during long-term culture and in vivo after...... transplantation to athymic nude mice. On average we obtained 29,000 NICCs from each pancreas. In a perifusion system, NICCs responded poorly to a glucose challenge alone, but 10 mmol/L arginine elicited a fourfold increase in insulin secretion and 16.7 mmol/L glucose + 10 mmol/L arginine caused a sevenfold...... co-stained for proliferation. However no co-staining was observed between insulin- and glucagon-positive cells or between hormone-and CK-positive cells. Following transplantation of 2000 NICCs under the renal capsule of diabetic nude mice, BG levels were normalized within an average of 13 weeks. Oral...

  5. Serum Is Not Necessary for Prior Pharmacological Activation of AMPK to Increase Insulin Sensitivity of Mouse Skeletal Muscle

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    Nicolas O. Jørgensen

    2018-04-01

    Full Text Available Exercise, contraction, and pharmacological activation of AMP-activated protein kinase (AMPK by 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR have all been shown to increase muscle insulin sensitivity for glucose uptake. Intriguingly, improvements in insulin sensitivity following contraction of isolated rat and mouse skeletal muscle and prior AICAR stimulation of isolated rat skeletal muscle seem to depend on an unknown factor present in serum. One study recently questioned this requirement of a serum factor by showing serum-independency with muscle from old rats. Whether a serum factor is necessary for prior AICAR stimulation to increase insulin sensitivity of mouse skeletal muscle is not known. Therefore, we investigated the necessity of serum for this effect of AICAR in mouse skeletal muscle. We found that the ability of prior AICAR stimulation to improve insulin sensitivity of mouse skeletal muscle did not depend on the presence of serum during AICAR stimulation. Although prior AICAR stimulation did not enhance proximal insulin signaling, insulin-stimulated phosphorylation of Tre-2/BUB2/CDC16- domain family member 4 (TBC1D4 Ser711 was greater in prior AICAR-stimulated muscle compared to all other groups. These results imply that the presence of a serum factor is not necessary for prior AMPK activation by AICAR to enhance insulin sensitivity of mouse skeletal muscle.

  6. Autocrine effect of Zn²⁺ on the glucose-stimulated insulin secretion.

    Science.gov (United States)

    Slepchenko, Kira G; Daniels, Nigel A; Guo, Aili; Li, Yang V

    2015-09-01

    It is well known that zinc (Zn(2+)) is required for the process of insulin biosynthesis and the maturation of insulin secretory granules in pancreatic beta (β)-cells, and that changes in Zn(2+) levels in the pancreas have been found to be associated with diabetes. Glucose-stimulation causes a rapid co-secretion of Zn(2+) and insulin with similar kinetics. However, we do not know whether Zn(2+) regulates insulin availability and secretion. Here we investigated the effect of Zn(2+) on glucose-stimulated insulin secretion (GSIS) in isolated mouse pancreatic islets. Whereas Zn(2+) alone (control) had no effect on the basal secretion of insulin, it significantly inhibited GSIS. The application of CaEDTA, by removing the secreted Zn(2+) from the extracellular milieu of the islets, resulted in significantly increased GSIS, suggesting an overall inhibitory role of secreted Zn(2+) on GSIS. The inhibitory action of Zn(2+) was mostly mediated through the activities of KATP/Ca(2+) channels. Furthermore, during brief paired-pulse glucose-stimulated Zn(2+) secretion (GSZS), Zn(2+) secretion following the second pulse was significantly attenuated, probably by the secreted endogenous Zn(2+) after the first pulse. Such an inhibition on Zn(2+) secretion following the second pulse was completely reversed by Zn(2+) chelation, suggesting a negative feedback mechanism, in which the initial glucose-stimulated Zn(2+) release inhibits subsequent Zn(2+) secretion, subsequently inhibiting insulin co-secretion as well. Taken together, these data suggest a negative feedback mechanism on GSZS and GSIS by Zn(2+) secreted from β-cells, and the co-secreted Zn(2+) may act as an autocrine inhibitory modulator.

  7. Islet-like clusters derived from mesenchymal stem cells in Wharton's Jelly of the human umbilical cord for transplantation to control type 1 diabetes.

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    Kuo Ching Chao

    Full Text Available BACKGROUND: There is a widespread interest in developing renewable sources of islet-replacement tissue for type I diabetes mellitus. Human mesenchymal cells isolated from the Wharton's jelly of the umbilical cord (HUMSCs, which can be easily obtained and processed compared with embryonic and bone marrow stem cells, possess stem cell properties. HUMSCs may be a valuable source for the generation of islets. METHODOLOGY AND PRINCIPAL FINDINGS: HUMSCs were induced to transform into islet-like cell clusters in vitro through stepwise culturing in neuron-conditioned medium. To assess the functional stability of the islet-like cell clusters in vivo, these cell clusters were transplanted into the liver of streptozotocin-induced diabetic rats via laparotomy. Glucose tolerance was measured on week 12 after transplantation accompanied with immunohistochemistry and electron microscopy analysis. These islet-like cell clusters were shown to contain human C-peptide and release human insulin in response to physiological glucose levels. Real-time RT-PCR detected the expressions of insulin and other pancreatic beta-cell-related genes (Pdx1, Hlxb9, Nkx2.2, Nkx6.1, and Glut-2 in these islet-like cell clusters. The hyperglycemia and glucose intolerance in streptozotocin-induced diabetic rats was significantly alleviated after xenotransplantation of islet-like cell clusters, without the use of immunosuppressants. In addition to the existence of islet-like cell clusters in the liver, some special fused liver cells were also found, which characterized by human insulin and nuclei-positive staining and possessing secretory granules. CONCLUSIONS AND SIGNIFICANCE: In this study, we successfully differentiate HUMSCs into mature islet-like cell clusters, and these islet-like cell clusters possess insulin-producing ability in vitro and in vivo. HUMSCs in Wharton's Jelly of the umbilical cord seem to be the preferential source of stem cells to convert into insulin

  8. Microencapsulated 3-dimensional sensor for the measurement of oxygen in single isolated pancreatic islets.

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    Wanyu Chen

    Full Text Available Oxygen consumption reflects multiple processes in pancreatic islets including mechanisms contributing to insulin secretion, oxidative stress and viability, providing an important readout in studies of islet function, islet viability and drug testing. Due to the scarcity, heterogeneity, and intrinsic kinetic properties of individual islets, it would be of great benefit to detect oxygen consumption by single islets. We present a novel method we have developed to image oxygen in single islets.Using a microfluidics system, individual islets and a fluorescent oxygen-sensitive dye were encased within a thin alginate polymer layer. Insulin secretion by the encapsulated islets was normal. Fluorescent signal from the encased dye, detected using a standard inverted fluorescence microscope and digital camera, was stable and proportional to the amount of oxygen in the media. When integrated into a perifusion system, the sensing system detected changes in response to metabolic substrates, mitochondrial poisons, and induced-oscillations. Glucose responses averaged 30.1±7.1% of the response to a metabolic inhibitor (cyanide, increases were observed in all cases (n = 6, and the system was able to resolve changes in oxygen consumption that had a period greater than 0.5 minutes. The sensing system operated similarly from 2-48 hours following encapsulation, and viability and function of the islets were not significantly affected by the encapsulation process.An oxygen-dependent dye situated around and within a pancreatic islet encapsulated by a thin layer of alginate was sensitive to changes in oxygen consumption, and was not harmful to the function or viability of islets over the course of two days. The microcapsule-based sensing method is particularly suited to assessing the effects of compounds (dose responses and time courses and chronic changes occurring over the course of days. The approach should be applicable to other cell types and dyes sensitive to other

  9. Accumulation of M1-like macrophages in type 2 diabetic islets is followed by a systemic shift in macrophage polarization.

    Science.gov (United States)

    Cucak, Helena; Grunnet, Lars Groth; Rosendahl, Alexander

    2014-01-01

    Human T2D is characterized by a low-grade systemic inflammation, loss of β-cells, and diminished insulin production. Local islet immunity is still poorly understood, and hence, we evaluated macrophage subpopulations in pancreatic islets in the well-established murine model of T2D, the db/db mouse. Already at 8 weeks of disease, on average, 12 macrophages were observed in the diabetic islets, whereas only two were recorded in the nondiabetic littermates. On a detailed level, the islet resident macrophages increased fourfold compared with nondiabetic littermates, whereas a pronounced recruitment (eightfold) of a novel subset of macrophages (CD68+F4/80-) was observed. The majority of the CD68+F4/80+ but only 40% of the CD68+F4/80- islet macrophages expressed CD11b. Both islet-derived macrophage subsets expressed moderate MHC-II, high galectin-3, and low CD80/CD86 levels, suggesting the cells to be macrophages rather than DCs. On a functional level, the vast majority of the macrophages in the diabetic islets was of the proinflammatory, M1-like phenotype. The systemic immunity in diabetic animals was characterized by a low-grade inflammation with elevated cytokine levels and increase of splenic cytokine, producing CD68+F4/80- macrophages. In late-stage diabetes, the cytokine signature changed toward a TGF-β-dominated profile, coinciding with a significant increase of galectin-3-positive macrophages in the spleen. In summary, our results show that proinflammatory M1-like galectin-3+ CD80/CD86(low) macrophages invade diabetic islets. Moreover, the innate immunity matures in a diabetes-dependent manner from an initial proinflammatory toward a profibrotic phenotype, supporting the concept that T2D is an inflammatory disease.

  10. Effect of Human Myotubes-Derived Media on Glucose-Stimulated Insulin Secretion

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    Maria L. Mizgier

    2017-01-01

    Full Text Available Fasting to postprandial transition requires a tight adjustment of insulin secretion to its demand, so tissue (e.g., skeletal muscle glucose supply is assured while hypo-/hyperglycemia are prevented. High muscle glucose disposal after meals is pivotal for adapting to increased glycemia and might drive insulin secretion through muscle-released factors (e.g., myokines. We hypothesized that insulin influences myokine secretion and then increases glucose-stimulated insulin secretion (GSIS. In conditioned media from human myotubes incubated with/without insulin (100 nmol/L for 24 h, myokines were qualitatively and quantitatively characterized using an antibody-based array and ELISA-based technology, respectively. C57BL6/J mice islets and Wistar rat beta cells were incubated for 24 h with control and conditioned media from noninsulin- and insulin-treated myotubes prior to GSIS determination. Conditioned media from insulin-treated versus nontreated myotubes had higher RANTES but lower IL6, IL8, and MCP1 concentration. Qualitative analyses revealed that conditioned media from noninsulin- and insulin-treated myotubes expressed 32 and 23 out of 80 myokines, respectively. Islets incubated with conditioned media from noninsulin-treated myotubes had higher GSIS versus control islets (p<0.05. Meanwhile, conditioned media from insulin-treated myotubes did not influence GSIS. In beta cells, GSIS was similar across conditions. In conclusion, factors being present in noninsulin-stimulated muscle cell-derived media appear to influence GSIS in mice islets.

  11. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic {beta} cells

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Mirshahi, Faridoddin [Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Grider, John R. [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Murthy, Karnam S., E-mail: skarnam@vcu.edu [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Sanyal, Arun J., E-mail: asanyal@mcvh-vcu.edu [Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA (United States)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer G protein coupled receptor TGR5 is expressed in mouse and human islets. Black-Right-Pointing-Pointer TGR5 is coupled to activation of Gs and Ca{sup 2+} release via cAMP/Epac/PLC-{epsilon} pathway. Black-Right-Pointing-Pointer Activation of TGR5 by bile salts and selective ligands causes insulin secretion. Black-Right-Pointing-Pointer TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic {beta} cells. In the present study, we have identified the expression of TGR5 in pancreatic {beta} cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated G{alpha}{sub s} and caused an increase in intracellular cAMP and Ca{sup 2+}. OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective G{alpha}{sub s} inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G{sub s}/cAMP/Ca{sup 2+} pathway. 8-pCPT-2 Prime -O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic {beta} cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  12. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic β cells

    International Nuclear Information System (INIS)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila; Mirshahi, Faridoddin; Grider, John R.; Murthy, Karnam S.; Sanyal, Arun J.

    2012-01-01

    Highlights: ► G protein coupled receptor TGR5 is expressed in mouse and human islets. ► TGR5 is coupled to activation of Gs and Ca 2+ release via cAMP/Epac/PLC-ε pathway. ► Activation of TGR5 by bile salts and selective ligands causes insulin secretion. ► TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic β cells. In the present study, we have identified the expression of TGR5 in pancreatic β cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated Gα s and caused an increase in intracellular cAMP and Ca 2+ . OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective Gα s inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G s /cAMP/Ca 2+ pathway. 8-pCPT-2′-O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic β cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  13. Overexpression of thioredoxin in islets transduced by a lentiviral vector prolongs graft survival in autoimmune diabetic NOD mice

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    Sytwu Huey-Kang

    2009-08-01

    Full Text Available Abstract Pancreatic islet transplantation is considered an appropriate treatment to achieve insulin independence in type I diabetic patients. However, islet isolation and transplantation-induced oxidative stress and autoimmune-mediated destruction are still the major obstacles to the long-term survival of graft islets in this potential therapy. To protect islet grafts from inflammatory damage and prolong their survival, we transduced islets with an antioxidative gene thioredoxin (TRX using a lentiviral vector before transplantation. We hypothesized that the overexpression of TRX in islets would prolong islet graft survival when transplanted into diabetic non-obese diabetic (NOD mice. Methods Islets were isolated from NOD mice and transduced with lentivirus carrying TRX (Lt-TRX or enhanced green fluorescence protein (Lt-eGFP, respectively. Transduced islets were transplanted under the left kidney capsule of female diabetic NOD mice, and blood glucose concentration was monitored daily after transplantation. The histology of the islet graft was assessed at the end of the study. The protective effect of TRX on islets was investigated. Results The lentiviral vector effectively transduced islets without altering the glucose-stimulating insulin-secretory function of islets. Overexpression of TRX in islets reduced hydrogen peroxide-induced cytotoxicity in vitro. After transplantation into diabetic NOD mice, euglycemia was maintained for significantly longer in Lt-TRX-transduced islets than in Lt-eGFP-transduced islets; the mean graft survival was 18 vs. 6.5 days (n = 9 and 10, respectively, p Conclusion We successfully transduced the TRX gene into islets and demonstrated that these genetically modified grafts are resistant to inflammatory insult and survived longer in diabetic recipients. Our results further support the concept that the reactive oxygen species (ROS scavenger and antiapoptotic functions of TRX are critical to islet survival after

  14. Ketosis Onset Type 2 Diabetes Had Better Islet β-Cell Function and More Serious Insulin Resistance

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    Hongyun Lu

    2014-01-01

    Full Text Available Diabetic ketosis had been identified as a characteristic of type 1 diabetes mellitus (T1DM, but now emerging evidence has identified that they were diagnosed as T2DM after long time follow up. This case control study was aimed at comparing the clinical characteristic, β-cell function, and insulin resistance of ketosis and nonketotic onset T2DM and providing evidence for treatment selection. 140 cases of newly diagnosed T2DM patients were divided into ketosis (62 cases and nonketotic onset group (78 cases. After correction of hyperglycemia and ketosis with insulin therapy, plasma C-peptide concentrations were measured at 0, 0.5, 1, 2, and 3 hours after 75 g glucose oral administration. Area under the curve (AUC of C-peptide was calculated. Homoeostasis model assessment was used to estimate basal β-cell function (HOMA-β and insulin resistance (HOMA-IR. Our results showed that ketosis onset group had higher prevalence of nonalcoholic fatty liver disease (NAFLD than nonketotic group (P=0.04. Ketosis onset group had increased plasma C-peptide levels at 0 h, 0.5 h, and 3 h and higher AUC0–0.5, AUC0–1, AUC0–3 (P<0.05. Moreover, this group also had higher HOMA-β and HOMA-IR than nonketotic group (P<0.05. From these data, we concluded that ketosis onset T2DM had better islet β-cell function and more serious insulin resistance than nonketotic onset T2DM.

  15. Characterization of Insulin-Immunoreactive Cells and Endocrine Cells Within the Duct System of the Adult Human Pancreas.

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    Li, Rong; Zhang, Xiaoxi; Yu, Lan; Zou, Xia; Zhao, Hailu

    2016-01-01

    The adult pancreatic duct system accommodates endocrine cells that have the potential to produce insulin. Here we report the characterization and distribution of insulin-immunoreactive cells and endocrine cells within the ductal units of adult human pancreas. Sequential pancreas sections from 12 nondiabetic adults were stained with biomarkers of ductal epithelial cells (cytokeratin 19), acinar cells (amylase), endocrine cells (chromogranin A; neuron-specific enolase), islet hormones (insulin, glucagon, somatostatin, pancreatic polypeptide), cell proliferation (Ki-67), and neogenesis (CD29). The number of islet hormone-immunoreactive cells increased from large ducts to the terminal branches. The insulin-producing cells outnumbered endocrine cells reactive for glucagon, somatostatin, or pancreatic polypeptide. The proportions of insulin-immunoreactive count compared with local islets (100% as a baseline) were 1.5% for the main ducts, 7.2% for interlobular ducts, 24.8% for intralobular ducts, 67.9% for intercalated ducts, and 348.9% for centroacinar cells. Both Ki-67- and CD29-labeled cells were predominantly localized in the terminal branches around the islets. The terminal branches also showed cells coexpressing islet hormones and cytokeratin 19. The adult human pancreatic ducts showed islet hormone-producing cells. The insulin-reactive cells predominantly localized in terminal branches where they may retain potential capability for β-cell neogenesis.

  16. Photoacoustic imaging of angiogenesis in subdermal islet transplant sites

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    Shi, Wei; Pawlick, Rena; Bruni, Antonio; Rafiei, Yasmin; Pepper, Andrew R.; Gala-Lopez, Boris; Choi, Min; Malcolm, Andrew; Zemp, Roger J.; Shapiro, A. M. James

    2016-03-01

    Exogenous insulin administration is the mainstay treatment therapy for patients with Type-1 diabetes mellitus (T1DM). However, for select patients, clinical islet transplantation is an alternative therapeutic treatment. In this procedure, islets are transplanted into the hepatic portal vein, and despite improved success within the last decade, obstacles are still associated with this approach. It has been discovered that the subcutaneous space may be an effective alternative site for islet transplantation, and may provide advantages of easy access and potential for simple monitoring. The ability to monitor islet viability and the transplant microenvironment may be key to future success in islet transplantation. A subcutaneous device-less technique has been developed to facilitate angiogenesis in the islet transplant site, however, a method for monitoring the potential engraftment site have yet to be explored fully. Here we demonstrate the ability to track angiogenesis in mice with 1, 2, 3 and 4 weeks post-catheter implant on both sides of the abdomen using a FujiFilm VisualSonics Vevo-LAZR system. Quantitative analysis on vessel densities exhibited gradual vessel growth successfully induced by catheter implantation. Our study demonstrates the ability of employing photoacoustic and micro-ultrasound imaging to track angiogenesis around the catheter site prior to islet transplantation.

  17. Zinc as a paracrine effector in pancreatic islet cell death.

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    Kim, B J; Kim, Y H; Kim, S; Kim, J W; Koh, J Y; Oh, S H; Lee, M K; Kim, K W; Lee, M S

    2000-03-01

    Because of a huge amount of Zn2+ in secretory granules of pancreatic islet beta-cells, Zn2+ released in certain conditions might affect the function or survival of islet cells. We studied potential paracrine effects of endogenous Zn2+ on beta-cell death. Zn2+ induced insulinoma/islet cell death in a dose-dependent manner. Chelation of released endogenous Zn2+ by CaEDTA significantly decreased streptozotocin (STZ)-induced islet cell death in an in vitro culture system simulating in vivo circumstances but not in the conventional culture system. Zn2+ chelation in vivo by continuous CaEDTA infusion significantly decreased the incidence of diabetes after STZ administration. N-(6-methoxy-quinolyl)-para-toluene-sulfonamide staining revealed that Zn2+ was densely deposited in degenerating islet cells 24 h after STZ treatment, which was decreased by CaEDTA infusion. We show here that Zn2+ is not a passive element for insulin storage but an active participant in islet cell death in certain conditions, which in time might contribute to the development of diabetes in aged people.

  18. Phosphatidylcholine (PC) biosynthesis in pancreatic islets of Langerhans

    International Nuclear Information System (INIS)

    Hoffman, J.M.; Laychock, S.G.

    1986-01-01

    Islets of Langerhans isolated from rat pancreata were incubated with [ 14 C]choline to determine the biosynthesis of PC by the CDP choline to determine the biosynthesis of PC by the CDPcholine pathway. Recovery of [ 14 C]PC in islet membranes was time-related, and stimulated by glucose (17mM) during 60 min. The rate of PC synthesis was constant during 60 min with glucose stimulation. In contrast, the sulfonylurea tolbutamide (2 mM) reduced the recovery of [ 14 C]choline in PC, and 8-bromo-cyclic AMP (5 mM) did not significantly affect [ 14 C]PC recovery. Incubation of islets in Ca 2+ -free medium enhanced glucose-stimulated recovery of [ 14 C]choline-labeled PC due to the inhibition of phospholipase and phospholipid hydrolysis. Inhibition of CTP:phosphocholine cytidylyltransferase with 5-deoxy-5'-isobutylthioadenosine (SIBA) reduced [ 14 C]PC levels and insulin release in a concentration dependent manner. Treatment with SIBA also reduced Mg 2+ -dependent Ca 2+ -ATPase activity in islet microsomes. Quantitation of membrane PC showed that glucose stimulation did not alter islet P levels. Thus, islet PC biosynthesis is linked to glucose stimulation and contributes to the maintenance of PC levels in membranes undergoing exocytosis and phospholipid hydrolysis. Adequate PC levels support Ca 2+ pump activity and secretory mechanisms

  19. Measurement of insulin and C-peptide excitatory test levels in gestational diabetes mellitus

    International Nuclear Information System (INIS)

    Du Tongxin; Wang Zizheng

    2001-01-01

    To investigate the function of islet β cells in patients with gestational diabetes mellitus (GDM), serum insulin and C-peptide (C-P) excitatory test levels were measured dynamically by radioimmunoassay in 41 patients with GDM and 30 normal pregnant controls. The results showed that there were significant difference in insulin and C-peptide excitatory test levels between normal pregnancy for 32-40 weeks and patients with GDM (P < 0.001). The secretory peak of insulin occurred at 60 min in normal pregnancy, while at 120 min in patients with GDM, and the recovery postponed in patients with GDM. The peak time for C-P was just as same as that of insulin, but the peak error for C-P between normal pregnant controls and patients with GDM was more larger than that for insulin and it recovered more slowly. It suggested that majority of islet β cells in patients with GDM were good enough for response to islet resistance factors and big stress from pregnancy, and also suggested a relation between pregnancy and islet β cells function

  20. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology

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    Rehana Akter

    2016-01-01

    Full Text Available The hormone islet amyloid polypeptide (IAPP, or amylin plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.

  1. Improvement in Outcomes of Clinical Islet Transplantation: 1999–2010

    Science.gov (United States)

    Barton, Franca B.; Rickels, Michael R.; Alejandro, Rodolfo; Hering, Bernhard J.; Wease, Stephen; Naziruddin, Bashoo; Oberholzer, Jose; Odorico, Jon S.; Garfinkel, Marc R.; Levy, Marlon; Pattou, Francois; Berney, Thierry; Secchi, Antonio; Messinger, Shari; Senior, Peter A.; Maffi, Paola; Posselt, Andrew; Stock, Peter G.; Kaufman, Dixon B.; Luo, Xunrong; Kandeel, Fouad; Cagliero, Enrico; Turgeon, Nicole A.; Witkowski, Piotr; Naji, Ali; O’Connell, Philip J.; Greenbaum, Carla; Kudva, Yogish C.; Brayman, Kenneth L.; Aull, Meredith J.; Larsen, Christian; Kay, Tom W.H.; Fernandez, Luis A.; Vantyghem, Marie-Christine; Bellin, Melena; Shapiro, A.M. James

    2012-01-01

    OBJECTIVE To describe trends of primary efficacy and safety outcomes of islet transplantation in type 1 diabetes recipients with severe hypoglycemia from the Collaborative Islet Transplant Registry (CITR) from 1999 to 2010. RESEARCH DESIGN AND METHODS A total of 677 islet transplant-alone or islet-after-kidney recipients with type 1 diabetes in the CITR were analyzed for five primary efficacy outcomes and overall safety to identify any differences by early (1999–2002), mid (2003–2006), or recent (2007–2010) transplant era based on annual follow-up to 5 years. RESULTS Insulin independence at 3 years after transplant improved from 27% in the early era (1999–2002, n = 214) to 37% in the mid (2003–2006, n = 255) and to 44% in the most recent era (2007–2010, n = 208; P = 0.006 for years-by-era; P = 0.01 for era alone). C-peptide ≥0.3 ng/mL, indicative of islet graft function, was retained longer in the most recent era (P islet reinfusion rate was lower: 48% by 1 year in 2007–2010 vs. 60–65% in 1999–2006 (P islet graft function (P islet transplantation in recipients who received transplants in 2007–2010 compared with those in 1999–2006, with fewer islet infusions and adverse events per recipient. PMID:22723582

  2. Nitric oxide is required for the insulin sensitizing effects of contraction in mouse skeletal muscle.

    Science.gov (United States)

    Zhang, Xinmei; Hiam, Danielle; Hong, Yet-Hoi; Zulli, Anthony; Hayes, Alan; Rattigan, Stephen; McConell, Glenn K

    2017-12-15

    People with insulin resistance or type 2 diabetes can substantially increase their skeletal muscle glucose uptake during exercise and insulin sensitivity after exercise. Skeletal muscle nitric oxide (NO) is important for glucose uptake during exercise, although how prior exercise increases insulin sensitivity is unclear. In the present study, we examined whether NO is necessary for normal increases in skeletal muscle insulin sensitivity after contraction ex vivo in mouse muscle. The present study uncovers, for the first time, a novel role for NO in the insulin sensitizing effects of ex vivo contraction, which is independent of blood flow. The factors regulating the increase in skeletal muscle insulin sensitivity after exercise are unclear. We examined whether nitric oxide (NO) is required for the increase in insulin sensitivity after ex vivo contractions. Isolated C57BL/6J mouse EDL muscles were contracted for 10 min or remained at rest (basal) with or without the NO synthase (NOS) inhibition (N G -monomethyl-l-arginine; l-NMMA; 100 μm). Then, 3.5 h post contraction/basal, muscles were exposed to saline or insulin (120 μU ml -1 ) with or without l-NMMA during the last 30 min. l-NMMA had no effect on basal skeletal muscle glucose uptake. The increase in muscle glucose uptake with insulin (57%) was significantly (P contraction (140% increase). NOS inhibition during the contractions had no effect on this insulin-sensitizing effect of contraction, whereas NOS inhibition during insulin prevented the increase in skeletal muscle insulin sensitivity post-contraction. Soluble guanylate cyclase inhibition, protein kinase G (PKG) inhibition or cyclic nucleotide phosphodiesterase inhibition each had no effect on the insulin-sensitizing effect of prior contraction. In conclusion, NO is required for increases in insulin sensitivity several hours after contraction of mouse skeletal muscle via a cGMP/PKG independent pathway. © 2017 The Authors. The Journal of Physiology

  3. Polyphenol-Rich Extract of Syzygium cumini Leaf Dually Improves Peripheral Insulin Sensitivity and Pancreatic Islet Function in Monosodium L-Glutamate-Induced Obese Rats

    Science.gov (United States)

    Sanches, Jonas R.; França, Lucas M.; Chagas, Vinicyus T.; Gaspar, Renato S.; dos Santos, Kayque A.; Gonçalves, Luciana M.; Sloboda, Deborah M.; Holloway, Alison C.; Dutra, Richard P.; Carneiro, Everardo M.; Cappelli, Ana Paula G.; Paes, Antonio Marcus de A.

    2016-01-01

    Syzygium cumini (L.) Skeels (Myrtaceae) has been traditionally used to treat a number of illnesses. Ethnopharmacological studies have particularly addressed antidiabetic and metabolic-related effects of extracts prepared from its different parts, especially seed, and pulp-fruit, however. there is a lack of studies on phytochemical profile and biological properties of its leaf. As there is considerable interest in bioactive compounds to treat metabolic syndrome and its clustered risk factors, we sought to characterize the metabolic effects of hydroethanolic extract of S. cumini leaf (HESc) on lean and monosodium L-glutamate (MSG)-induced obese rats. HPLC-MS/MS characterization of the HESc polyphenolic profile, at 254 nm, identified 15 compounds pertaining to hydrolysable tannin and flavanol subclasses. At 60 days of age, both groups were randomly assigned to receive HESc (500 mg/kg) or vehicle for 30 days. At the end of treatment, obese+HESc exhibited significantly lower body weight gain, body mass index, and white adipose tissue mass, compared to obese rats receiving vehicle. Obese rats treated with HESc showed a twofold increase in lipolytic activity in the periepididymal fat pad, as well as, brought triglyceride levels in serum, liver and skeletal muscle back to levels close those found in lean animals. Furthermore, HESc also improved hyperinsulinemia and insulin resistance in obese+HESc rats, which resulted in partial reversal of glucose intolerance, as compared to obese rats. HESc had no effect in lean rats. Assessment of ex vivo glucose-stimulated insulin secretion showed HESc potentiated pancreatic function in islets isolated from both lean and obese rats treated with HESc. In addition, HESc (10–1000 μg/mL) increased glucose stimulated insulin secretion from both isolated rat islets and INS-1E β-cells. These data demonstrate that S. cumini leaf improved peripheral insulin sensitivity via stimulating/modulating β-cell insulin release, which was associated

  4. Polyphenol-rich extract of Syzygium cumini leaf dually improves peripheral insulin sensitivity and pancreatic islet function in monosodium L-glutamate-induced obese rats

    Directory of Open Access Journals (Sweden)

    Jonas Rodrigues Sanches

    2016-03-01

    Full Text Available Syzygium cumini (L. Skeels (Myrtaceae has been traditionally used to treat a number of illnesses. Ethnopharmacological studies have particularly addressed antidiabetic and metabolic-related effects of extracts prepared from its different parts, especially seed and pulp-fruit, however there is a lack of studies on phytochemical profile and biological properties of its leaf. As there is considerable interest in bioactive compounds to treat metabolic syndrome and its clustered risk factors, we sought to characterize the metabolic effects of hydroethanolic extract of S. cumini leaf (HESc on lean and monosodium L-glutamate (MSG-induced obese rats. HPLC-MS/MS characterization of the HESc polyphenolic profile, at 254 nm, identified 15 compounds pertaining to hydrolysable tannin and flavanol subclasses. At 60 days of age, both groups were randomly assigned to receive HESc (500 mg/kg or vehicle for 30 days. At the end of treatment, obese+HESc exhibited significantly lower body weight gain, body mass index, and white adipose tissue mass, compared to obese rats receiving vehicle. Obese rats treated with HESc showed a 2-fold increase in lipolytic activity in the periepididymal fat pad, as well as, brought triglyceride levels in serum, liver and skeletal muscle back to levels close those found in lean animals. Furthermore, HESc also improved hyperinsulinemia and insulin resistance in obese+HESc rats, which resulted in partial reversal of glucose intolerance, as compared to obese rats. HESc had no effect in lean rats. Assessment of ex vivo glucose-stimulated insulin secretion showed HESc potentiated pancreatic function in islets isolated from both lean and obese rats treated with HESc. In addition, HESc (10 – 1000 ug/mL increased glucose stimulated insulin secretion from both isolated rat islets and INS-1E beta cells. These data demonstrate that S. cumini leaf improved peripheral insulin sensitivity via stimulating/modulating beta cell insulin release

  5. A novel method for murine intrahepatic islet transplantation via cecal vein.

    Science.gov (United States)

    Byun, Nari; Kim, Hyun-Je; Min, Byoung-Hoon; Shin, Jun-Seop; Yoon, Il-Hee; Kim, Jong-Min; Kim, Yong-Hee; Park, Chung-Gyu

    2015-12-01

    Islet transplantation is one of the most beneficial treatment modality to treat type 1 diabetic patients with frequent hypoglycemic unawareness. In clinical setting, human islets are infused via portal vein and are settled in the end-portal venules in the liver. However, mouse islets are transplanted into kidney subcapsule or liver through direct portal vein. These conventional transplantation methods have several drawbacks such as different physiological environments around the transplanted islets in kidney subcapsule from the liver and high mortality rate in direct portal vein approach. In this study, we introduced murine intrahepatic islet transplantation method via cecal vein to have the same surgical operation route in humans as well as guaranteeing low mortality rate after islet transplantation. With this protocol, consistent normoglycemia can be obtained in diabetic mice, while keeping operation-related mortality extremely low. This approach with easier accessibility and low mortality will make murine intrahepatic islet transplantation a useful model for studying immunological mechanisms such as strong innate and adaptive immune responses that occur in human islet transplantation. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Pancreatectomy and autologous islet transplantation for painful chronic pancreatitis: indications and outcomes.

    Science.gov (United States)

    Bellin, Melena D; Sutherland, David E R; Robertson, R Paul

    2012-08-01

    Total pancreatectomy with intrahepatic autoislet transplantation (TP/IAT) is a definitive treatment for relentlessly painful chronic pancreatitis. Pain relief is reported to be achieved in approximately 80% of patients. Overall, 30% to 40% achieve insulin independence, and 70% of recipients remain insulin independent for > 2 years, sometimes longer if > 300 000 islets are successfully transplanted. Yet, this approach to chronic pancreatitis is underemphasized in the general medical and surgical literature and vastly underused in the United States. This review emphasizes the history and metabolic outcomes of TP/IAT and considers its usefulness in the context of other, more frequently used approaches, such as operative intervention with partial pancreatectomy and/or lateral pancreaticojejunostomy (Puestow procedure), as well as endoscopic retrograde cholangiopancreatography with pancreatic duct modification and stent placement. Distal pancreatectomy and Puestow procedures compromise isolation of islet mass, and adversely affect islet autotransplant outcomes. Therefore, when endoscopic measures fail to relieve pain in severe chronic pancreatitis, we recommend early intervention with TP/IAT.

  7. β-cell-specific IL-2 therapy increases islet Foxp3+Treg and suppresses type 1 diabetes in NOD mice.

    Science.gov (United States)

    Johnson, Mark C; Garland, Alaina L; Nicolson, Sarah C; Li, Chengwen; Samulski, R Jude; Wang, Bo; Tisch, Roland

    2013-11-01

    Interleukin-2 (IL-2) is a critical cytokine for the homeostasis and function of forkhead box p3-expressing regulatory T cells (Foxp3(+)Tregs). Dysregulation of the IL-2-IL-2 receptor axis is associated with aberrant Foxp3(+)Tregs and T cell-mediated autoimmune diseases such as type 1 diabetes. Treatment with recombinant IL-2 has been reported to enhance Foxp3(+)Tregs and suppress different models of autoimmunity. However, efficacy of IL-2 therapy is dependent on achieving sufficient levels of IL-2 to boost tissue-resident Foxp3(+)Tregs while avoiding the potential toxic effects of systemic IL-2. With this in mind, adeno-associated virus (AAV) vector gene delivery was used to localize IL-2 expression to the islets of NOD mice. Injection of a double-stranded AAV vector encoding IL-2 driven by a mouse insulin promoter (dsAAVmIP-IL2) increased Foxp3(+)Tregs in the islets but not the draining pancreatic lymph nodes. Islet Foxp3(+)Tregs in dsAAVmIP-IL2-treated NOD mice exhibited enhanced fitness marked by increased expression of Bcl-2, proliferation, and suppressor function. In contrast, ectopic IL-2 had no significant effect on conventional islet-infiltrating effector T cells. Notably, β-cell-specific IL-2 expression suppressed late preclinical type 1 diabetes in NOD mice. Collectively, these findings demonstrate that β-cell-specific IL-2 expands an islet-resident Foxp3(+)Tregs pool that effectively suppresses ongoing type 1 diabetes long term.

  8. Characterization of insulin-like growth factor I produced by fetal rat pancreatic islets

    International Nuclear Information System (INIS)

    Scharfmann, R.; Corvol, M.; Czernichow, P.

    1989-01-01

    Pancreatic islets were prepared from 22-day-old rat fetuses. After 5 days of culture in dishes allowing cell attachment, neoformed islets were kept free floating in RPMI-1640 medium (16.5 mM glucose, 1% fetal calf serum). The islets were then pulsed with [ 3 H]leucine and [ 35 S]methionine for 24 h. The conditioned medium was acidified with acetic acid (final pH 2.7), desalted, concentrated, and gel filtered on Bio-Gel P100 in acid conditions. The radioactive material that comigrated with immunoreactive insulinlike growth factor I (IGF-I) produced by the islets was pooled, concentrated, and further characterized by reverse-phase high-performance liquid chromatography on a C18 Bondapak column with a linear gradient of acetonitrile (20-80%). The radioactive material that eluted as pure IGF-I (40% acetonitrile) was further studied by chromatofocusing on a Pharmacia PBE 94 column. A sharp radioactive peak containing [ 3 H]leucine and [ 35 S]methionine was eluted at pH 8.55. This material was immunoprecipitated with an antiserum to IGF-I. This study demonstrated that fetal islet cells synthesize molecules that are, by several criteria, equivalent to native IGF-I

  9. Use of additives, scaffolds and extracellular matrix components for improvement of human pancreatic islet outcomes in vitro: A systematic review.

    Science.gov (United States)

    Lemos, Natália Emerim; de Almeida Brondani, Letícia; Dieter, Cristine; Rheinheimer, Jakeline; Bouças, Ana Paula; Bauermann Leitão, Cristiane; Crispim, Daisy; Bauer, Andrea Carla

    2017-09-03

    Pancreatic islet transplantation is an established treatment to restore insulin independence in type 1 diabetic patients. Its success rates have increased lately based on improvements in immunosuppressive therapies and on islet isolation and culture. It is known that the quality and quantity of viable transplanted islets are crucial for the achievement of insulin independence and some studies have shown that a significant number of islets are lost during culture time. Thus, in an effort to improve islet yield during culture period, researchers have tested a variety of additives in culture media as well as alternative culture devices, such as scaffolds. However, due to the use of different categories of additives or devices, it is difficult to draw a conclusion on the benefits of these strategies. Therefore, the aim of this systematic review was to summarize the results of studies that described the use of medium additives, scaffolds or extracellular matrix (ECM) components during human pancreatic islets culture. PubMed and Embase repositories were searched. Of 5083 articles retrieved, a total of 37 articles fulfilled the eligibility criteria and were included in the review. After data extraction, articles were grouped as follows: 1) "antiapoptotic/anti-inflammatory/antioxidant," 2) "hormone," 3) "sulphonylureas," 4) "serum supplements," and 5) "scaffolds or ECM components." The effects of the reviewed additives, ECM or scaffolds on islet viability, apoptosis and function (glucose-stimulated insulin secretion - GSIS) were heterogeneous, making any major conclusion hard to sustain. Overall, some "antiapoptotic/anti-inflammatory/antioxidant" additives decreased apoptosis and improved GSIS. Moreover, islet culture with ECM components or scaffolds increased GSIS. More studies are needed to define the real impact of these strategies in improving islet transplantation outcomes.

  10. Pravastatin Improves Glucose Regulation and Biocompatibility of Agarose Encapsulated Porcine Islets following Transplantation into Pancreatectomized Dogs

    Directory of Open Access Journals (Sweden)

    Lawrence S. Gazda

    2014-01-01

    Full Text Available The encapsulation of porcine islets is an attractive methodology for the treatment of Type I diabetes. In the current study, the use of pravastatin as a mild anti-inflammatory agent was investigated in pancreatectomized diabetic canines transplanted with porcine islets encapsulated in agarose-agarose macrobeads and given 80 mg/day of pravastatin (n=3 while control animals did not receive pravastatin (n=3. Control animals reached preimplant insulin requirements on days 18, 19, and 32. Pravastatin-treated animals reached preimplant insulin requirements on days 22, 27, and 50. Two animals from each group received a second macrobead implant: control animals remained insulin-free for 15 and 21 days (AUC = 3003 and 5078 mg/dL/24 hr days 1 to 15 and reached preimplant insulin requirements on days 62 and 131. Pravastatin treated animals remained insulin-free for 21 and 34 days (AUC = 1559 and 1903 mg/dL/24 hr days 1 to 15 and reached preimplant insulin requirements on days 38 and 192. Total incidence (83.3% versus 64.3% and total severity (22.7 versus 18.3 of inflammation on tissue surfaces were higher in the control group at necropsy. These findings support pravastatin therapy in conjunction with the transplantation of encapsulated xenogeneic islets for the treatment of diabetes mellitus.

  11. The Beta Cell in Its Cluster: Stochastic Graphs of Beta Cell Connectivity in the Islets of Langerhans.

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    Deborah A Striegel

    2015-08-01

    Full Text Available Pancreatic islets of Langerhans consist of endocrine cells, primarily α, β and δ cells, which secrete glucagon, insulin, and somatostatin, respectively, to regulate plasma glucose. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Due to the central functional significance of this local connectivity in the placement of β cells in an islet, it is important to characterize it quantitatively. However, quantification of the seemingly stochastic cytoarchitecture of β cells in an islet requires mathematical methods that can capture topological connectivity in the entire β-cell population in an islet. Graph theory provides such a framework. Using large-scale imaging data for thousands of islets containing hundreds of thousands of cells in human organ donor pancreata, we show that quantitative graph characteristics differ between control and type 2 diabetic islets. Further insight into the processes that shape and maintain this architecture is obtained by formulating a stochastic theory of β-cell rearrangement in whole islets, just as the normal equilibrium distribution of the Ornstein-Uhlenbeck process can be viewed as the result of the interplay between a random walk and a linear restoring force. Requiring that rearrangements maintain the observed quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that β-cell rearrangement is dependent on its connectivity in order to maintain an optimal cluster size in both normal and T2D islets.

  12. The Beta Cell in Its Cluster: Stochastic Graphs of Beta Cell Connectivity in the Islets of Langerhans.

    Science.gov (United States)

    Striegel, Deborah A; Hara, Manami; Periwal, Vipul

    2015-08-01

    Pancreatic islets of Langerhans consist of endocrine cells, primarily α, β and δ cells, which secrete glucagon, insulin, and somatostatin, respectively, to regulate plasma glucose. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Due to the central functional significance of this local connectivity in the placement of β cells in an islet, it is important to characterize it quantitatively. However, quantification of the seemingly stochastic cytoarchitecture of β cells in an islet requires mathematical methods that can capture topological connectivity in the entire β-cell population in an islet. Graph theory provides such a framework. Using large-scale imaging data for thousands of islets containing hundreds of thousands of cells in human organ donor pancreata, we show that quantitative graph characteristics differ between control and type 2 diabetic islets. Further insight into the processes that shape and maintain this architecture is obtained by formulating a stochastic theory of β-cell rearrangement in whole islets, just as the normal equilibrium distribution of the Ornstein-Uhlenbeck process can be viewed as the result of the interplay between a random walk and a linear restoring force. Requiring that rearrangements maintain the observed quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that β-cell rearrangement is dependent on its connectivity in order to maintain an optimal cluster size in both normal and T2D islets.

  13. Alginate Microencapsulation of Human Islets Does Not Increase Susceptibility to Acute Hypoxia

    Directory of Open Access Journals (Sweden)

    I. K. Hals

    2013-01-01

    Full Text Available Islet transplantation in diabetes is hampered by the need of life-long immunosuppression. Encapsulation provides partial immunoprotection but could possibly limit oxygen supply, a factor that may enhance hypoxia-induced beta cell death in the early posttransplantation period. Here we tested susceptibility of alginate microencapsulated human islets to experimental hypoxia (0.1–0.3% O2 for 8 h, followed by reoxygenation on viability and functional parameters. Hypoxia reduced viability as measured by MTT by 33.8±3.5% in encapsulated and 42.9±5.2% in nonencapsulated islets (P<0.2. Nonencapsulated islets released 37.7% (median more HMGB1 compared to encapsulated islets after hypoxic culture conditions (P<0.001. Glucose-induced insulin release was marginally affected by hypoxia. Basal oxygen consumption was equally reduced in encapsulated and nonencapsulated islets, by 22.0±6.1% versus 24.8±5.7%. Among 27 tested cytokines/chemokines, hypoxia increased the secretion of IL-6 and IL-8/CXCL8 in both groups of islets, whereas an increase of MCP-1/CCL2 was seen only with nonencapsulated islets. Conclusion. Alginate microencapsulation of human islets does not increase susceptibility to acute hypoxia. This is a positive finding in relation to potential use of encapsulation for islet transplantation.

  14. Clinical islet isolation and transplantation outcomes with deceased cardiac death donors are similar to neurological determination of death donors.

    Science.gov (United States)

    Andres, Axel; Kin, Tatsuya; O'Gorman, Doug; Livingstone, Scott; Bigam, David; Kneteman, Norman; Senior, Peter; Shapiro, A M James

    2016-01-01

    In islet transplantation, deceased cardiac death (DCD) donation has been identified as a potential extended source. There are currently no studies comparing outcomes between these categories, and our goal was to compare islet isolation success rates and transplantation outcomes between DCD and neurological determination of death (NDD) donors. Islet isolations from 15 DCD and 418 NDD were performed in our centre between September 2008 and September 2014. Donor variables, islet yields, metabolic function of isolated isled and insulin requirements at 1-month post-transplant were compared. Compared to NDD, pancreata from DCD were more often procured locally and donors required less vasopressive support (P islet yields were similar between NDD and DCD (576 vs. 608 × 10(3) islet equivalent, P = 0.628 and 386 vs. 379, P = 0.881, respectively). The metabolic function was similar between NDD and DCD, as well as the mean decrease in insulin requirement at 1-month post-transplantation (NDD: 64.82%; DCD: 60.17% reduction, P = 0.517). These results support the broader use of DCD pancreata for islet isolation. A much larger DCD islet experience will be required to truly determine noninferiority of both short- and long-term outcomes. © 2015 Steunstichting ESOT.

  15. Microencapsulated 3-Dimensional Sensor for the Measurement of Oxygen in Single Isolated Pancreatic Islets

    Science.gov (United States)

    Khalil, Gamal; Sweet, Ian R.; Shen, Amy Q.

    2012-01-01

    Background Oxygen consumption reflects multiple processes in pancreatic islets including mechanisms contributing to insulin secretion, oxidative stress and viability, providing an important readout in studies of islet function, islet viability and drug testing. Due to the scarcity, heterogeneity, and intrinsic kinetic properties of individual islets, it would be of great benefit to detect oxygen consumption by single islets. We present a novel method we have developed to image oxygen in single islets. Methodology/Principal Findings Using a microfluidics system, individual islets and a fluorescent oxygen-sensitive dye were encased within a thin alginate polymer layer. Insulin secretion by the encapsulated islets was normal. Fluorescent signal from the encased dye, detected using a standard inverted fluorescence microscope and digital camera, was stable and proportional to the amount of oxygen in the media. When integrated into a perifusion system, the sensing system detected changes in response to metabolic substrates, mitochondrial poisons, and induced-oscillations. Glucose responses averaged 30.1±7.1% of the response to a metabolic inhibitor (cyanide), increases were observed in all cases (n = 6), and the system was able to resolve changes in oxygen consumption that had a period greater than 0.5 minutes. The sensing system operated similarly from 2–48 hours following encapsulation, and viability and function of the islets were not significantly affected by the encapsulation process. Conclusions/Significance An oxygen-dependent dye situated around and within a pancreatic islet encapsulated by a thin layer of alginate was sensitive to changes in oxygen consumption, and was not harmful to the function or viability of islets over the course of two days. The microcapsule-based sensing method is particularly suited to assessing the effects of compounds (dose responses and time courses) and chronic changes occurring over the course of days. The approach should be

  16. Resealable, optically accessible, PDMS-free fluidic platform for ex vivo interrogation of pancreatic islets.

    Science.gov (United States)

    Lenguito, Giovanni; Chaimov, Deborah; Weitz, Jonathan R; Rodriguez-Diaz, Rayner; Rawal, Siddarth A K; Tamayo-Garcia, Alejandro; Caicedo, Alejandro; Stabler, Cherie L; Buchwald, Peter; Agarwal, Ashutosh

    2017-02-28

    We report the design and fabrication of a robust fluidic platform built out of inert plastic materials and micromachined features that promote optimized convective fluid transport. The platform is tested for perfusion interrogation of rodent and human pancreatic islets, dynamic secretion of hormones, concomitant live-cell imaging, and optogenetic stimulation of genetically engineered islets. A coupled quantitative fluid dynamics computational model of glucose stimulated insulin secretion and fluid dynamics was first utilized to design device geometries that are optimal for complete perfusion of three-dimensional islets, effective collection of secreted insulin, and minimization of system volumes and associated delays. Fluidic devices were then fabricated through rapid prototyping techniques, such as micromilling and laser engraving, as two interlocking parts from materials that are non-absorbent and inert. Finally, the assembly was tested for performance using both rodent and human islets with multiple assays conducted in parallel, such as dynamic perfusion, staining and optogenetics on standard microscopes, as well as for integration with commercial perfusion machines. The optimized design of convective fluid flows, use of bio-inert and non-absorbent materials, reversible assembly, manual access for loading and unloading of islets, and straightforward integration with commercial imaging and fluid handling systems proved to be critical for perfusion assay, and particularly suited for time-resolved optogenetics studies.

  17. Current Status of Immunomodulatory and Cellular Therapies in Preclinical and Clinical Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Preeti Chhabra

    2011-01-01

    Full Text Available Clinical islet transplantation is a -cell replacement strategy that represents a possible definitive intervention for patients with type 1 diabetes, offering substantial benefits in terms of lowering daily insulin requirements and reducing incidences of debilitating hypoglycemic episodes and unawareness. Despite impressive advances in this field, a limiting supply of islets, inadequate means for preventing islet rejection, and the deleterious diabetogenic and nephrotoxic side effects associated with chronic immunosuppressive therapy preclude its wide-spread applicability. Islet transplantation however allows a window of opportunity for attempting various therapeutic manipulations of islets prior to transplantation aimed at achieving superior transplant outcomes. In this paper, we will focus on the current status of various immunosuppressive and cellular therapies that promote graft function and survival in preclinical and clinical islet transplantation with special emphasis on the tolerance-inducing capacity of regulatory T cells as well as the -cells regenerative capacity of stem cells.

  18. Sympathetic Innervation during Development Is Necessary for Pancreatic Islet Architecture and Functional Maturation

    Directory of Open Access Journals (Sweden)

    Philip Borden

    2013-07-01

    Full Text Available Sympathetic neurons depend on target-derived neurotrophic cues to control their survival and growth. However, whether sympathetic innervation contributes reciprocally to the development of target tissues is less clear. Here, we report that sympathetic innervation is necessary for the formation of the pancreatic islets of Langerhans and for their functional maturation. Genetic or pharmacological ablation of sympathetic innervation during development resulted in altered islet architecture, reduced insulin secretion, and impaired glucose tolerance in mice. Similar defects were observed with pharmacological blockade of β-adrenergic signaling. Conversely, the administration of a β-adrenergic agonist restored islet morphology and glucose tolerance in deinnervated animals. Furthermore, in neuron-islet cocultures, sympathetic neurons promoted islet cell migration in a β-adrenergic-dependent manner. This study reveals that islet architecture requires extrinsic inductive cues from neighboring tissues such as sympathetic nerves and suggests that early perturbations in sympathetic innervation might underlie metabolic disorders.

  19. The relative contribution of insulin secretory capacity, insulin action, and incretins to metabolic control after islet transplantation in dogs

    NARCIS (Netherlands)

    van der Burg, MPM; van Suylichem, PTR; Guicherit, OR; Frolich, M; Lemkes, HHPJ; Gooszen, HG

    Adequate metabolic control is central to the concept of islet transplantation, but has received limited attention. We studied metabolic control in 8 dogs at 6-9 months after intrasplenic autografting of similar to 25% of the normal mass islets - as compared to 30 controls. A similar posttransplant

  20. Disturbed α-Cell Function in Mice with β-Cell Specific Overexpression of Human Islet Amyloid Polypeptide

    Directory of Open Access Journals (Sweden)

    Bo Ahrén

    2008-01-01

    Full Text Available Exogenous administration of islet amyloid polypeptide (IAPP has been shown to inhibit both insulin and glucagon secretion. This study examined α-cell function in mice with β-cell specific overexpression of human IAPP (hIAPP after an oral protein gavage (75 mg whey protein/mouse. Baseline glucagon levels were higher in transgenic mice (41±4.0 pg/mL, n=6 than in wildtype animals (19±5.1 pg/mL, n=5, P=.015. In contrast, the glucagon response to protein was impaired in transgenic animals (21±2.7 pg/mL in transgenic mice versus 38±5.7 pg/mL in wildtype mice at 15 minutes; P=.027. Baseline insulin levels did not differ between the groups, while the insulin response, as the glucagon response, was impaired after protein challenge (P=.018. Glucose levels were not different between the groups and did not change significantly after protein gavage. Acetaminophen was given through gavage to the animals (2 mg/mouse to estimate gastric emptying. The plasma acetaminophen profile was similar in the two groups of mice. We conclude that disturbances in glucagon secretion exist in mice with β-cell specific overexpression of human IAPP, which are not secondary to changes in gastric emptying. The reduced glucagon response to protein challenge may reflect a direct inhibitory influence of hIAPP on glucagon secretion.

  1. Stevia Nonsweetener Fraction Displays an Insulinotropic Effect Involving Neurotransmission in Pancreatic Islets

    Science.gov (United States)

    Pavanello, Audrei; Peixoto, Giuliana Maria Ledesma; Matiusso, Camila Cristina Ianoni; de Moraes, Ana Maria Praxedes; Martins, Isabela Peixoto; Palma-Rigo, Kesia; da Silva Franco, Claudinéia Conationi; Milani, Paula Gimenez; Dacome, Antonio Sérgio; da Costa, Silvio Claudio; de Freitas Mathias, Paulo Cezar; Mareze-Costa, Cecília Edna

    2018-01-01

    Stevia rebaudiana (Bert.) Bertoni besides being a source of noncaloric sweeteners is also an important source of bioactive molecules. Many plant extracts, mostly obtained with ethyl acetate solvent, are rich in polyphenol compounds that present insulinotropic effects. To investigate whether the nonsweetener fraction, which is rich in phenolic compounds isolated from Stevia rebaudiana with the solvent ethyl acetate (EAF), has an insulinotropic effect, including interference at the terminals of the autonomic nervous system of the pancreatic islets of rats. Pancreatic islets were isolated from Wistar rats and incubated with EAF and inhibitory or stimulatory substances of insulin secretion, including cholinergic and adrenergic agonists and antagonists. EAF potentiates glucose-stimulated insulin secretion (GSIS) only in the presence of high glucose and calcium-dependent concentrations. EAF increased muscarinic insulinotropic effects in pancreatic islets, interfering with the muscarinic receptor subfamily M3. Adrenergic inhibitory effects on GSIS were attenuated in the presence of EAF, which interfered with the adrenergic α 2 receptor. Results suggest that EAF isolated from stevia leaves is a potential therapy for treating type 2 diabetes mellitus by stimulating insulin secretion only in high glucose concentrations, enhancing parasympathetic signal transduction and inhibiting sympathetic signal transduction in beta cells. PMID:29853880

  2. Stevia Nonsweetener Fraction Displays an Insulinotropic Effect Involving Neurotransmission in Pancreatic Islets

    Directory of Open Access Journals (Sweden)

    Silvano Piovan

    2018-01-01

    Full Text Available Stevia rebaudiana (Bert. Bertoni besides being a source of noncaloric sweeteners is also an important source of bioactive molecules. Many plant extracts, mostly obtained with ethyl acetate solvent, are rich in polyphenol compounds that present insulinotropic effects. To investigate whether the nonsweetener fraction, which is rich in phenolic compounds isolated from Stevia rebaudiana with the solvent ethyl acetate (EAF, has an insulinotropic effect, including interference at the terminals of the autonomic nervous system of the pancreatic islets of rats. Pancreatic islets were isolated from Wistar rats and incubated with EAF and inhibitory or stimulatory substances of insulin secretion, including cholinergic and adrenergic agonists and antagonists. EAF potentiates glucose-stimulated insulin secretion (GSIS only in the presence of high glucose and calcium-dependent concentrations. EAF increased muscarinic insulinotropic effects in pancreatic islets, interfering with the muscarinic receptor subfamily M3. Adrenergic inhibitory effects on GSIS were attenuated in the presence of EAF, which interfered with the adrenergic α2 receptor. Results suggest that EAF isolated from stevia leaves is a potential therapy for treating type 2 diabetes mellitus by stimulating insulin secretion only in high glucose concentrations, enhancing parasympathetic signal transduction and inhibiting sympathetic signal transduction in beta cells.

  3. Sweet taste receptor expressed in pancreatic beta-cells activates the calcium and cyclic AMP signaling systems and stimulates insulin secretion.

    Directory of Open Access Journals (Sweden)

    Yuko Nakagawa

    Full Text Available BACKGROUND: Sweet taste receptor is expressed in the taste buds and enteroendocrine cells acting as a sugar sensor. We investigated the expression and function of the sweet taste receptor in MIN6 cells and mouse islets. METHODOLOGY/PRINCIPAL FINDINGS: The expression of the sweet taste receptor was determined by RT-PCR and immunohistochemistry. Changes in cytoplasmic Ca(2+ ([Ca(2+](c and cAMP ([cAMP](c were monitored in MIN6 cells using fura-2 and Epac1-camps. Activation of protein kinase C was monitored by measuring translocation of MARCKS-GFP. Insulin was measured by radioimmunoassay. mRNA for T1R2, T1R3, and gustducin was expressed in MIN6 cells. In these cells, artificial sweeteners such as sucralose, succharin, and acesulfame-K increased insulin secretion and augmented secretion induced by glucose. Sucralose increased biphasic increase in [Ca(2+](c. The second sustained phase was blocked by removal of extracellular calcium and addition of nifedipine. An inhibitor of inositol(1, 4, 5-trisphophate receptor, 2-aminoethoxydiphenyl borate, blocked both phases of [Ca(2+](c response. The effect of sucralose on [Ca(2+](c was inhibited by gurmarin, an inhibitor of the sweet taste receptor, but not affected by a G(q inhibitor. Sucralose also induced sustained elevation of [cAMP](c, which was only partially inhibited by removal of extracellular calcium and nifedipine. Finally, mouse islets expressed T1R2 and T1R3, and artificial sweeteners stimulated insulin secretion. CONCLUSIONS: Sweet taste receptor is expressed in beta-cells, and activation of this receptor induces insulin secretion by Ca(2+ and cAMP-dependent mechanisms.

  4. Decreased insulin secretion in pregnant rats fed a low protein diet.

    Science.gov (United States)

    Gao, Haijun; Ho, Eric; Balakrishnan, Meena; Yechoor, Vijay; Yallampalli, Chandra

    2017-10-01

    Low protein (LP) diet during pregnancy leads to reduced plasma insulin levels in rodents, but the underlying mechanisms remain unclear. Glucose is the primary insulin secretagogue, and enhanced glucose-stimulated insulin secretion (GSIS) in beta cells contributes to compensation for insulin resistance and maintenance of glucose homeostasis during pregnancy. In this study, we hypothesized that plasma insulin levels in pregnant rats fed LP diet are reduced due to disrupted GSIS of pancreatic islets. We first confirmed reduced plasma insulin levels, then investigated in vivo insulin secretion by glucose tolerance test and ex vivo GSIS of pancreatic islets in the presence of glucose at different doses, and KCl, glibenclamide, and L-arginine. Main findings include (1) plasma insulin levels were unaltered on day 10, but significantly reduced on days 14-22 of pregnancy in rats fed LP diet compared to those of control (CT) rats; (2) insulin sensitivity was unchanged, but glucose intolerance was more severe in pregnant rats fed LP diet; (3) GSIS in pancreatic islets was lower in LP rats compared to CT rats in the presence of glucose, KCl, and glibenclamide, and the response to L-arginine was abolished in LP rats; and (4) the total insulin content in pancreatic islets and expression of Ins2 were reduced in LP rats, but expression of Gcg was unaltered. These studies demonstrate that decreased GSIS in beta cells of LP rats contributes to reduced plasma insulin levels, which may lead to placental and fetal growth restriction and programs hypertension and other metabolic diseases in offspring. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Delayed revascularization of islets after transplantation by IL-6 blockade in pig to non-human primate islet xenotransplantation model.

    Science.gov (United States)

    Min, Byoung-Hoon; Shin, Jun-Seop; Kim, Jong-Min; Kang, Seong-Jun; Kim, Hyun-Je; Yoon, Il-Hee; Park, Su-Kyoung; Choi, Ji-Won; Lee, Min-Suk; Park, Chung-Gyu

    2018-01-01

    Pancreatic islet transplantation is currently proven as a promising treatment for type 1 diabetes patients with labile glycemic control and severe hypoglycemia unawareness. Upon islet transplantation, revascularization is essential for proper functioning of the transplanted islets. As IL-6 is important for endothelial cell survival and systemic inflammation related to xenograft, the effect of IL-6 receptor antagonist, tocilizumab, on revascularization of the transplanted islets was examined in pig to non-human primate islet xenotransplantation model. Also, the endothelial cell origin in a new vessel of the transplanted pig islets was determined. Pig islets were isolated from designated pathogen-free (DPF) SNU miniature pigs and transplanted via portal vein into five streptozotocin-induced diabetic monkeys. One group (n = 2, basal group) was treated with anti-thymoglobulin (ATG), anti-CD40 antibody (2C10R4), sirolimus, and tacrolimus, and the other group was additionally given tocilizumab on top of basal immunosuppression (n = 3, Tocilizumab group). To confirm IL-6 blocking effect, C-reactive protein (CRP) levels and serum IL-6 concentration were measured. Scheduled biopsy of the margin of the posterior segment right lobe inferior of the liver was performed at 3 weeks after transplantation to assess the degree of revascularization of the transplanted islets. Immunohistochemical staining using anti-insulin, anti-CD31 antibodies, and lectin IB4 was conducted to find the origin of endothelial cells in the islet graft. CRP significantly increased at 1~2 days after transplantation in Basal group, but not in Tocilizumab group, and higher serum IL-6 concentration was measured in latter group, showing the biological potency of tocilizumab. In Basal group, well-developed endothelial cells were observed on the peri- and intraislet area, whereas the number of CD31 + cells in the intraislet space was significantly reduced in Tocilizumab group. Finally, new endothelial

  6. Quantitative measurement of zinc secretion from pancreatic islets with high temporal resolution using droplet-based microfluidics.

    Science.gov (United States)

    Easley, Christopher J; Rocheleau, Jonathan V; Head, W Steven; Piston, David W

    2009-11-01

    We assayed glucose-stimulated insulin secretion (GSIS) from live, murine islets of Langerhans in microfluidic devices by the downstream formation of aqueous droplets. Zinc ions, which are cosecreted with insulin from beta-cells, were quantitatively measured from single islets with high temporal resolution using a fluorescent indicator, FluoZin-3. Real-time storage of secretions into droplets (volume of 0.470 +/- 0.009 nL) effectively preserves the temporal chemical information, allowing reconstruction of the secretory time record. The use of passive flow control within the device removes the need for syringe pumps, requiring only a single hand-held syringe. Under stimulatory glucose levels (11 mM), bursts of zinc as high as approximately 800 fg islet(-1) min(-1) were measured. Treatment with diazoxide effectively blocked zinc secretion, as expected. High temporal resolution reveals two major classes of oscillations in secreted zinc, with predominate periods at approximately 20-40 s and approximately 5-10 min. The more rapid oscillation periods match closely with those of intraislet calcium oscillations, while the slower oscillations are consistent with insulin pulses typically measured in bulk islet experiments or in the bloodstream. This droplet sampling technique should be widely applicable to time-resolved cellular secretion measurements, either in real-time or for postprocessing.

  7. Autologous Mesenchymal Stem Cell and Islet Cotransplantation: Safety and Efficacy.

    Science.gov (United States)

    Wang, Hongjun; Strange, Charlie; Nietert, Paul J; Wang, Jingjing; Turnbull, Taylor L; Cloud, Colleen; Owczarski, Stefanie; Shuford, Betsy; Duke, Tara; Gilkeson, Gary; Luttrell, Louis; Hermayer, Kathie; Fernandes, Jyotika; Adams, David B; Morgan, Katherine A

    2018-01-01

    Islet engraftment after transplantation is impaired by high rates of islet/β cell death caused by cellular stressors and poor graft vascularization. We studied whether cotransplantation of ex vivo expanded autologous bone marrow-derived mesenchymal stem cells (MSCs) with islets is safe and beneficial in chronic pancreatitis patients undergoing total pancreatectomy with islet autotransplantation. MSCs were harvested from the bone marrow of three islet autotransplantation patients and expanded at our current Good Manufacturing Practices (cGMP) facility. On the day of islet transplantation, an average dose of 20.0 ± 2.6 ×10 6 MSCs was infused with islets via the portal vein. Adverse events and glycemic control at baseline, 6, and 12 months after transplantation were compared with data from 101 historical control patients. No adverse events directly related to the MSC infusions were observed. MSC patients required lower amounts of insulin during the peritransplantation period (p = .02 vs. controls) and had lower 12-month fasting blood glucose levels (p = .02 vs. controls), smaller C-peptide declines over 6 months (p = .01 vs. controls), and better quality of life compared with controls. In conclusion, our pilot study demonstrates that autologous MSC and islet cotransplantation may be a safe and potential strategy to improve islet engraftment after transplantation. (Clinicaltrials.gov registration number: NCT02384018). Stem Cells Translational Medicine 2018;7:11-19. © 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  8. Functional and histological findings of the islets of Langerhans in mice after fractioned telecobalt irradiations with tumor doses

    International Nuclear Information System (INIS)

    Konermann, G.; Petersen, K.G.; Slanina, J.; Blachnitzky, E.O.; Kraft, C.; Freiburg Univ.

    1979-01-01

    After a local radiation exposure of the pancreas of mice to a total dose of 5000 rd ( 60 Co gamma radiation over five weeks with 5 x 200 rd per week), there is no demonstrable alteration, even at long term, of the glucose tolerance and the insulin secretion of isolated islets of Langerhans in vitro and of the density of a histochemically prepared islet secretion. However, the proinsuline synthesis under glucose loading is reduced by about 40%. A radiogenic reduction of the total insulin content in the islet tissue of 27,6% is accompanied by a diminution of the body weight of 10% and a reduction of the organ weight of pancreas, liver and spleen of 20%, 13% and 47%. In view of these findings and taking into account a cellular death rate in the islet tissue of 21% immediately after the radiotherapy and of 5,8% eight weeks post irradiationem, the authors suppose a compensating secretion by the remaining islet cells which is sufficient under normal conditions. Signs of a tissue degeneration near the vessels are clearer in the exocrine pancreas than in the islet tissue. (orig.) 891 MG/orig. 892 RKD [de

  9. Production of peptide antisera specific for mouse and rat proinsulin C-peptide 2

    DEFF Research Database (Denmark)

    Blume, N; Madsen, O D; Kofod, Hans

    1990-01-01

    for antibody binding to the immunizing antigen. Antisera to C-peptide 2, stained islet beta-cells on mouse and rat, but not monkey pancreas sections in immunocytochemical analysis. Preabsorption to the synthetic C-peptide 2, but not the synthetic mouse and rat C-peptide 1 abolished staining. In conclusion we......Mice and rats have two functional non-allelic insulin genes. By using a synthetic peptide representing a common sequence in mouse and rat C-peptide 2 as antigen, we have produced rabbit antisera specific for an epitope which is not present in mouse or rat C-peptide 1. Long-term immunization did...... not seem to increase the end point titre as tested in direct ELISA. The specificity of the antiserum was determined by competitive ELISA and histochemistry on pancreas sections. Only the synthetic C-peptide 2, but not the homologous synthetic C-peptide 1 from mouse and rat competed efficiently in ELISA...

  10. Involvement of insulin-degrading enzyme in insulin- and atrial natriuretic peptide-sensitive internalization of amyloid-β peptide in mouse brain capillary endothelial cells.

    Science.gov (United States)

    Ito, Shingo; Ohtsuki, Sumio; Murata, Sho; Katsukura, Yuki; Suzuki, Hiroya; Funaki, Miho; Tachikawa, Masanori; Terasaki, Tetsuya

    2014-01-01

    Cerebral clearance of amyloid-β peptide (Aβ), which is implicated in Alzheimer's disease, involves elimination across the blood-brain barrier (BBB), and we previously showed that an insulin-sensitive process is involved in the case of Aβ1-40. The purpose of this study was to clarify the molecular mechanism of the insulin-sensitive Aβ1-40 elimination across mouse BBB. An in vivo cerebral microinjection study demonstrated that [125I]hAβ1-40 elimination from mouse brain was inhibited by human natriuretic peptide (hANP), and [125I]hANP elimination was inhibited by hAβ1-40, suggesting that hAβ1-40 and hANP share a common elimination process. Internalization of [125I]hAβ1-40 into cultured mouse brain capillary endothelial cells (TM-BBB4) was significantly inhibited by either insulin, hANP, other natriuretic peptides or insulin-degrading enzyme (IDE) inhibitors, but was not inhibited by phosphoramidon or thiorphan. Although we have reported the involvement of natriuretic peptide receptor C (Npr-C) in hANP internalization, cells stably expressing Npr-C internalized [125I]hANP but not [125I]hAβ1-40, suggesting that there is no direct interaction between Npr-C and hAβ1-40. IDE was detected in plasma membrane of TM-BBB4 cells, and internalization of [125I]hAβ1-40 by TM-BBB4 cells was reduced by IDE-targeted siRNAs. We conclude that elimination of hAβ1-40 from mouse brain across the BBB involves an insulin- and ANP-sensitive process, mediated by IDE expressed in brain capillary endothelial cells.

  11. Spontaneous Hypoglycemia After Islet Autotransplantation for Chronic Pancreatitis.

    Science.gov (United States)

    Lin, Yu Kuei; Faiman, Charles; Johnston, Philip C; Walsh, R Matthew; Stevens, Tyler; Bottino, Rita; Hatipoglu, Betul A

    2016-10-01

    Spontaneous hypoglycemia has been reported in patients after total pancreatectomy (TP) and islet autotransplantation (IAT) with maintained insulin independence. Details surrounding these events have not been well described. The objective of the study was to determine the frequency and characteristics of spontaneous hypoglycemia in patients undergoing TP-IAT and/or to ascertain predictive or protective factors of its development. This was an observational cohort study in 40 patients who underwent TP-IAT from August 2008 to May 2014, with a median follow-up of 34 months. The study was conducted at a single institution (Cleveland Clinic). Patients included recipients of TP-IAT. The intervention included small, frequent meals in those patients who developed spontaneous hypoglycemia. Incidence of spontaneous hypoglycemia development, characteristics of the patients developing hypoglycemia, and their response to small, frequent meals were measured. Six of 12 patients, who maintained insulin independence, developed spontaneous hypoglycemia. The episodes could be fasting, postprandial, and/or exercise associated, with the frequency ranging from two to three times daily to once every 1-2 weeks. All patients experienced at least one episode that required external assistance, glucagon administration, and/or emergent medical attention. Patients who developed hypoglycemia had a lower median age and tended to have a lower median islet equivalent/kg body weight but a higher median total islet equivalent, body mass index, and homeostatic model assessment for insulin resistance score. All patients who received small, frequent meal intervention had improvement in severity and/or frequency of the hypoglycemic episodes. Spontaneous hypoglycemia is prevalent after TP-IAT. Although the underlying pathophysiology responsible for these hypoglycemia events remains to be elucidated, small, frequent meal intervention is helpful in ameliorating this condition.

  12. Laparoscopic Total Pancreatectomy With Islet Autotransplantation and Intraoperative Islet Separation as a Treatment for Patients With Chronic Pancreatitis.

    Science.gov (United States)

    Fan, Caleb J; Hirose, Kenzo; Walsh, Christi M; Quartuccio, Michael; Desai, Niraj M; Singh, Vikesh K; Kalyani, Rita R; Warren, Daniel S; Sun, Zhaoli; Hanna, Marie N; Makary, Martin A

    2017-06-01

    Pain management of patients with chronic pancreatitis (CP) can be challenging. Laparoscopy has been associated with markedly reduced postoperative pain but has not been widely applied to total pancreatectomy with islet autotransplantation (TPIAT). To examine the feasibility of using laparoscopic TPIAT (L-TPIAT) in the treatment of CP. Thirty-two patients with CP presented for TPIAT at a tertiary hospital from January 1, 2013, through December 31, 2015. Of the 22 patients who underwent L-TPIAT, 2 patients converted to an open procedure because of difficult anatomy and prior surgery. Pain and glycemic outcomes were recorded at follow-up visits every 3 to 6 months postoperatively. Operative outcomes included operative time, islet isolation time, warm ischemia time, islet equivalent (IE) counts, estimated blood loss, fluid resuscitation, and blood transfusions. Postoperative outcomes included length of stay, all-cause 30-day readmission rate, postoperative complications, mortality rate, subjective pain measurements, opioid use, random C-peptide levels, insulin requirements, and glycated hemoglobin level. Of the 32 patients who presented for TPIAT, 20 underwent L-TPIAT (8 men and 12 women; mean [SD] age, 39 [13] years; age range, 21-58 years). Indication for surgery was CP attributable to genetic mutation (n = 9), idiopathic pancreatitis (n = 6), idiopathic pancreatitis with pancreas divisum (n = 3), and alcohol abuse (n = 2). Mean (SD) operative time was 493 (78) minutes, islet isolation time was 185 (37) minutes, and warm ischemia time was 51 (62) minutes. The mean (SD) IE count was 1325 (1093) IE/kg. The mean (SD) length of stay was 11 (5) days, and the all-cause 30-day readmission rate was 35% (7 of 20 patients). None of the patients experienced postoperative surgical site infection, hernia, or small-bowel obstruction, and none died. Eighteen patients (90%) had a decrease or complete resolution of pain, and 12 patients (60%) no longer required opioid

  13. Effect of liver histopathology on islet cell engraftment in the model mimicking autologous islet cell transplantation.

    Science.gov (United States)

    Desai, Chirag S; Khan, Khalid M; Ma, Xiaobo; Li, Henghong; Wang, Juan; Fan, Lijuan; Chen, Guoling; Smith, Jill P; Cui, Wanxing

    2017-11-02

    The inflammatory milieu in the liver as determined by histopathology is different in individual patients undergoing autologous islet cell transplantation. We hypothesized that inflammation related to fatty-liver adversely impacts islet survival. To test this hypothesis, we used a mouse model of fatty-liver to determine the outcome of syngeneic islet transplantation after chemical pancreatectomy. Mice (C57BL/6) were fed a high-fat-diet from 6 weeks of age until attaining a weight of ≥28 grams (6-8 weeks) to produce a fatty liver (histologically > 30% fat);steatosis was confirmed with lipidomic profile of liver tissue. Islets were infused via the intra-portal route in fatty-liver and control mice after streptozotocin induction of diabetes. Outcomes were assessed by the rate of euglycemia, liver histopathology, evaluation of liver inflammation by measuring tissue cytokines IL-1β and TNF-α by RT-PCR and CD31 expression by immunohistochemistry. The difference in the euglycemic fraction between the normal liver group (90%, 9/10) and the fatty-liver group (37.5%, 3/8) was statistically significant at the 18 th day post- transplant and was maintained to the end of the study (day 28) (p = 0.019, X 2 = 5.51). Levels of TNF-α and IL-1β were elevated in fatty-liver mice (p = 0.042, p = 0.037). Compared to controls cytokine levels were elevated after islet cell transplantation and in transplanted fatty-liver mice as compared to either fatty- or islet transplant group alone (p = NS). A difference in the histochemical pattern of CD31 could not be determined. Fatty-liver creates an inflammatory state which adversely affects the outcome of autologous islet cell transplantation.

  14. Development of a transgenic mouse model to study the immunogenicity of recombinant human insulin

    NARCIS (Netherlands)

    Torosantucci, Riccardo; Brinks, Vera; Kijanka, Grzegorz; Halim, Liem Andhyk; Sauerborn, Melody; Schellekens, Huub; Jiskoot, Wim

    2014-01-01

    Mouse models are commonly used to assess the immunogenicity of therapeutic proteins and to investigate the immunological processes leading to antidrug antibodies. The aim of this work was to develop a transgenic (TG) Balb/c mouse model for evaluating the immunogenicity of recombinant human insulin

  15. Development of (99m)Tc-Labeled Pyridyl Benzofuran Derivatives To Detect Pancreatic Amylin in Islet Amyloid Model Mice.

    Science.gov (United States)

    Yoshimura, Masashi; Ono, Masahiro; Watanabe, Hiroyuki; Kimura, Hiroyuki; Saji, Hideo

    2016-06-15

    While islet amyloid deposition comprising amylin is one of pathological hallmarks of type 2 diabetes mellitus (T2DM), no useful amylin-imaging probe has been reported. In this study, we evaluated two (99m)Tc-labeled pyridyl benzofuran derivatives as novel amylin-imaging probes using the newly established islet amyloid model mouse. Binding experiments in vitro demonstrated that [(99m)Tc]1 displayed a higher affinity for amylin aggregates than [(99m)Tc]2. Autoradiographic studies using human pancreas sections with T2DM revealed that [(99m)Tc]1 clearly labeled islet amyloid in T2DM pancreatic sections, while [(99m)Tc]2 did not. Although the initial uptake of [(99m)Tc]1 by the normal mouse pancreas was low (0.74%ID/g at 2 min post-injection), [(99m)Tc]1 showed higher retention in the model mouse pancreas than that of the normal mouse, and exhibited strong binding to amylin aggregates in the living pancreas of the model mice. These results suggest that [(99m)Tc]1 is a potential imaging probe targeting islet amyloids in the T2DM pancreas.

  16. Modular tissue engineering for the vascularization of subcutaneously transplanted pancreatic islets.

    Science.gov (United States)

    Vlahos, Alexander E; Cober, Nicholas; Sefton, Michael V

    2017-08-29

    The transplantation of pancreatic islets, following the Edmonton Protocol, is a promising treatment for type I diabetics. However, the need for multiple donors to achieve insulin independence reflects the large loss of islets that occurs when islets are infused into the portal vein. Finding a less hostile transplantation site that is both minimally invasive and able to support a large transplant volume is necessary to advance this approach. Although the s.c. site satisfies both these criteria, the site is poorly vascularized, precluding its utility. To address this problem, we demonstrate that modular tissue engineering results in an s.c. vascularized bed that enables the transplantation of pancreatic islets. In streptozotocin-induced diabetic SCID/beige mice, the injection of 750 rat islet equivalents embedded in endothelialized collagen modules was sufficient to restore and maintain normoglycemia for 21 days; the same number of free islets was unable to affect glucose levels. Furthermore, using CLARITY, we showed that embedded islets became revascularized and integrated with the host's vasculature, a feature not seen in other s.c. Collagen-embedded islets drove a small (albeit not significant) shift toward a proangiogenic CD206 + MHCII - (M2-like) macrophage response, which was a feature of module-associated vascularization. While these results open the potential for using s.c. islet delivery as a treatment option for type I diabetes, the more immediate benefit may be for the exploration of revascularized islet biology.

  17. Isolation, transplantation, and functional studies of adult porcine islets of Langerhans

    DEFF Research Database (Denmark)

    Nielsen, Thomas Buschmann; Yderstræde, Knud Bonnet; Beck-Nielsen, Henning

    2002-01-01

    that was only partially increased by additional challenge with arginine. More than 50% of DNA and 90% of the insulin content was lost during a one-week culture period. With some batch-to-batch variation, in 15 of 25 cases, 4,000 to 7,000 porcine islets cured streptozotocin diabetic nude mice within three weeks......Transplantation of islets of Langerhans is a possible treatment for type-I diabetes mellitus. However, there is a shortage of donors for such transplantations and the pig may be an alternative source of donor organs. The aims of the study reported here were to establish a method for adult porcine...... following transplantation. In conclusion, it is possible to isolate viable islets from adult pigs, using a semiautomatic set-up. With batch-to-batch variation, the islets are able to revert diabetes mellitus when transplanted to diabetic nude mice....

  18. Current Status of Immunomodulatory and Cellular Therapies in Preclinical and Clinical Islet Transplantation

    Science.gov (United States)

    Chhabra, Preeti; Brayman, Kenneth L.

    2011-01-01

    Clinical islet transplantation is a β-cell replacement strategy that represents a possible definitive intervention for patients with type 1 diabetes, offering substantial benefits in terms of lowering daily insulin requirements and reducing incidences of debilitating hypoglycemic episodes and unawareness. Despite impressive advances in this field, a limiting supply of islets, inadequate means for preventing islet rejection, and the deleterious diabetogenic and nephrotoxic side effects associated with chronic immunosuppressive therapy preclude its wide-spread applicability. Islet transplantation however allows a window of opportunity for attempting various therapeutic manipulations of islets prior to transplantation aimed at achieving superior transplant outcomes. In this paper, we will focus on the current status of various immunosuppressive and cellular therapies that promote graft function and survival in preclinical and clinical islet transplantation with special emphasis on the tolerance-inducing capacity of regulatory T cells as well as the β-cells regenerative capacity of stem cells. PMID:22046502

  19. The hyperbolic effect of density and strength of inter beta-cell coupling on islet bursting: a theoretical investigation

    Directory of Open Access Journals (Sweden)

    Wang Xujing

    2008-08-01

    Full Text Available Abstract Background Insulin, the principal regulating hormone of blood glucose, is released through the bursting of the pancreatic islets. Increasing evidence indicates the importance of islet morphostructure in its function, and the need of a quantitative investigation. Recently we have studied this problem from the perspective of islet bursting of insulin, utilizing a new 3D hexagonal closest packing (HCP model of islet structure that we have developed. Quantitative non-linear dependence of islet function on its structure was found. In this study, we further investigate two key structural measures: the number of neighboring cells that each β-cell is coupled to, nc, and the coupling strength, gc. Results β-cell clusters of different sizes with number of β-cells nβ ranging from 1–343, nc from 0–12, and gc from 0–1000 pS, were simulated. Three functional measures of islet bursting characteristics – fraction of bursting β-cells fb, synchronization index λ, and bursting period Tb, were quantified. The results revealed a hyperbolic dependence on the combined effect of nc and gc. From this we propose to define a dimensionless cluster coupling index or CCI, as a composite measure for islet morphostructural integrity. We show that the robustness of islet oscillatory bursting depends on CCI, with all three functional measures fb, λ and Tb increasing monotonically with CCI when it is small, and plateau around CCI = 1. Conclusion CCI is a good islet function predictor. It has the potential of linking islet structure and function, and providing insight to identify therapeutic targets for the preservation and restoration of islet β-cell mass and function.

  20. A Historical Perspective on the Identification of Cell Types in Pancreatic Islets of Langerhans by Staining and Histochemical Techniques.

    Science.gov (United States)

    Baskin, Denis G

    2015-08-01

    Before the middle of the previous century, cell types of the pancreatic islets of Langerhans were identified primarily on the basis of their color reactions with histological dyes. At that time, the chemical basis for the staining properties of islet cells in relation to the identity, chemistry and structure of their hormones was not fully understood. Nevertheless, the definitive islet cell types that secrete glucagon, insulin, and somatostatin (A, B, and D cells, respectively) could reliably be differentiated from each other with staining protocols that involved variations of one or more tinctorial techniques, such as the Mallory-Heidenhain azan trichrome, chromium hematoxylin and phloxine, aldehyde fuchsin, and silver impregnation methods, which were popularly used until supplanted by immunohistochemical techniques. Before antibody-based staining methods, the most bona fide histochemical techniques for the identification of islet B cells were based on the detection of sulfhydryl and disulfide groups of insulin. The application of the classical islet tinctorial staining methods for pathophysiological studies and physiological experiments was fundamental to our understanding of islet architecture and the physiological roles of A and B cells in glucose regulation and diabetes. © The Author(s) 2015.

  1. Zinc stimulates glucose oxidation and glycemic control by modulating the insulin signaling pathway in human and mouse skeletal muscle cell lines.

    Science.gov (United States)

    Norouzi, Shaghayegh; Adulcikas, John; Sohal, Sukhwinder Singh; Myers, Stephen

    2018-01-01

    Zinc is a metal ion that is an essential cell signaling molecule. Highlighting this, zinc is an insulin mimetic, activating cellular pathways that regulate cellular homeostasis and physiological responses. Previous studies have linked dysfunctional zinc signaling with several disease states including cancer, obesity, cardiovascular disease and type 2 diabetes. The present study evaluated the insulin-like effects of zinc on cell signaling molecules including tyrosine, PRSA40, Akt, ERK1/2, SHP-2, GSK-3β and p38, and glucose oxidation in human and mouse skeletal muscle cells. Insulin and zinc independently led to the phosphorylation of these proteins over a 60-minute time course in both mouse and human skeletal muscle cells. Similarly, utilizing a protein array we identified that zinc could active the phosphorylation of p38, ERK1/2 and GSK-3B in human and ERK1/2 and GSK-3B in mouse skeletal muscle cells. Glucose oxidation assays were performed on skeletal muscle cells treated with insulin, zinc, or a combination of both and resulted in a significant induction of glucose consumption in mouse (pzinc alone. Insulin, as expected, increased glucose oxidation in mouse (pzinc and insulin did not augment glucose consumption in these cells. Zinc acts as an insulin mimetic, activating key molecules implicated in cell signaling to maintain glucose homeostasis in mouse and human skeletal muscle cells. Zinc is an important metal ion implicated in several biological processes. The role of zinc as an insulin memetic in activating key signaling molecules involved in glucose homeostasis could provide opportunities to utilize this ion therapeutically in treating disorders associated with dysfunctional zinc signaling.

  2. First Identification of the Toxicity of Microcystins on Pancreatic Islet Function in Humans and the Involved Potential Biomarkers.

    Science.gov (United States)

    Zhao, Yanyan; Xue, Qingju; Su, Xiaomei; Xie, Liqiang; Yan, Yunjun; Wang, Lixiao; Steinman, Alan D

    2016-03-15

    Microcystins (MCs) produced by cyanobacteria have been recognized as a major public health threat. However, the toxicity of MCs to humans is still largely unknown. In this study, we examined the changes in pancreatic islet function in fishers exposed to ambient levels of MCs at Lake Taihu and, using a mouse model, explored the molecular mechanisms involved in toxicity. MCs content in the serum of fishers tested positive, with a range from 0.10 to 0.64 μg/L. Both lower blood insulin levels (2.26 ± 0.96 μIU/mL) and impaired fasting glucose were found in participants from the Meiliang Bay area in Lake Taihu, where MC-LR levels were substantially greater than the MC threshold established by WHO for drinking water. Animal experiments showed that glucose level increased by 27.9% in mice exposed to 5 μg/kg bw and decreased by 41.5% in mice exposed to 20 μg/kg bw. Blood insulin levels declined by 21.9% and 56.2% in mice exposed to 5 and 20 μg/kg bw MC-LR, respectively, which was consistent with the results observed in fishers. Furthermore, the diabetes gene pdx1 and several other proteins (such as Ppp3ca, Ide, Marcks, Pgk1, Suclg1, Ndufs4) involved in insulin secretion were identified for the first time in mice following MC-LR exposure; these biomarkers were considered responsible for MC-LR induced islet dysfunction. This study suggests that subchronic exposure to environmental levels of MCs may increase the risk of the occurrence of diabetes in humans.

  3. Preparation of rat islet B-cell-enriched fractions by light-scatter flow cytometry

    International Nuclear Information System (INIS)

    Rabinovitch, A.; Russell, T.; Shienvold, F.; Noel, J.; Files, N.; Patel, Y.; Ingram, M.

    1982-01-01

    Flow cytometry has been examined as a method to separate islet cells into homogeneous subpopulations. Collagenase-isolated rat islets were dissociated into single cells and these were analyzed and sorted according to their low forward angle light scattering properties by using automated flow cytometry. Light scatter histograms showed two peaks of viable cells. Radioimmunoassay of hormone content in cell fractions collected across the the two peaks showed that glucagon-containing cells were concentrated towards the left side of the left peak and somatostatin-containing cells were concentrated towards the right side of the left peak, whereas insulin-containing cells were clearly enriched in the right peak. The B-cell-enriched fraction (90% B cells, 3% A cells, 2% D cells) exhibited significant insulin secretory responses to glucose (16.7 mM), and 3-isobutyl-1-methylxanthine (0.1 mM), during a 24-h culture period, and these responses were slightly greater than those observed in the original mixed islet cell preparation (66% B cells, 14% A cells, and 4% D cells). These results indicate that flow cytometry can be applied to sort pancreatic islet cells into populations enriched in specific endocrine cell types for further study of the functions of individual cell types

  4. Development of a Rapid Insulin Assay by Homogenous Time-Resolved Fluorescence.

    Directory of Open Access Journals (Sweden)

    Zachary J Farino

    Full Text Available Direct measurement of insulin is critical for basic and clinical studies of insulin secretion. However, current methods are expensive and time-consuming. We developed an insulin assay based on homogenous time-resolved fluorescence that is significantly more rapid and cost-effective than current commonly used approaches. This assay was applied effectively to an insulin secreting cell line, INS-1E cells, as well as pancreatic islets, allowing us to validate the assay by elucidating mechanisms by which dopamine regulates insulin release. We found that dopamine functioned as a significant negative modulator of glucose-stimulated insulin secretion. Further, we showed that bromocriptine, a known dopamine D2/D3 receptor agonist and newly approved drug used for treatment of type II diabetes mellitus, also decreased glucose-stimulated insulin secretion in islets to levels comparable to those caused by dopamine treatment.

  5. Immunohistochemical detection of vimentin in pancreatic islet β- and α-cells of macrosomic infants of diabetic and nondiabetic mothers.

    Science.gov (United States)

    Krivova, Yuliya S; Proshchina, Alexandra E; Barabanov, Valeriy M; Barinova, Irina V; Saveliev, Sergey V

    2018-02-01

    Expression of the intermediate filament protein vimentin has been recently observed in the pancreatic islet β- and α-cells of humans with type 2 diabetes mellitus. It was suggested that the presence of vimentin in endocrine cells may indicate islet tissue renewal, or potentially represent the dedifferentiation of endocrine cells, which could contribute to the onset of type 2 diabetes or islet cell dysfunction. To analyze the expression of vimentin in pancreatic β- and α-cells of macrosomic infants of diabetic and nondiabetic mothers. Pancreatic samples of five macrosomic infants (gestational age 34-40weeks) from three diabetic and two nondiabetic mothers were compared to six control infants (32-40weeks, weight appropriate for gestational age) from normoglycemic mothers. Pancreatic autopsy samples were examined by double immunofluorescent labeling with antibodies against vimentin and either insulin or glucagon. Alterations in the endocrine pancreas were measured using morphometric methods, then data were statistically analyzed. In the pancreatic islets of macrosomic infants from diabetic and nondiabetic mothers, we observed vimentin-positive cells, some of which simultaneously contained insulin or glucagon. We also quantitatively showed that the presence of such cells was associated with hypertrophy and hyperplasia of the islets, and with an increase in β- and α-cell density. We speculate that the appearance of vimentin-positive islet cells may reflect induction of differentiation in response to the increased insulin demand, and vimentin may serve as an early marker of endocrine pancreas disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Total pancreatectomy and islet autotransplantation in children for chronic pancreatitis: indication, surgical techniques, postoperative management, and long-term outcomes.

    Science.gov (United States)

    Chinnakotla, Srinath; Bellin, Melena D; Schwarzenberg, Sarah J; Radosevich, David M; Cook, Marie; Dunn, Ty B; Beilman, Gregory J; Freeman, Martin L; Balamurugan, A N; Wilhelm, Josh; Bland, Barbara; Jimenez-Vega, Jose M; Hering, Bernhard J; Vickers, Selwyn M; Pruett, Timothy L; Sutherland, David E R

    2014-07-01

    Describe the surgical technique, complications, and long-term outcomes of total pancreatectomy and islet autotransplantation (TP-IAT) in a large series of pediatric patients. Surgical management of childhood pancreatitis is not clear; partial resection or drainage procedures often provide transient pain relief, but long-term recurrence is common due to the diffuse involvement of the pancreas. Total pancreatectomy (TP) removes the source of the pain, whereas islet autotransplantation (IAT) potentially can prevent or minimize TP-related diabetes. Retrospective review of 75 children undergoing TP-IAT for chronic pancreatitis who had failed medical, endoscopic, or surgical treatment between 1989 and 2012. Pancreatitis pain and the severity of pain statistically improved in 90% of patients after TP-IAT (P Puestow procedure (P = 0.018), lower body surface area (P = 0.048), higher islet equivalents (IEQ) per kilogram body weight (P = 0.001), and total IEQ (100,000) (P = 0.004) were associated with insulin independence. By multivariate analysis, 3 factors were associated with insulin independence after TP-IAT: (1) male sex, (2) lower body surface area, and (3) higher total IEQ per kilogram body weight. Total IEQ (100,000) was the single factor most strongly associated with insulin independence (odds ratio = 2.62; P < 0.001). Total pancreatectomy and islet autotransplantation provides sustained pain relief and improved quality of life. The β-cell function is dependent on islet yield. Total pancreatectomy and islet autotransplantation is an effective therapy for children with painful pancreatitis that failed medical and/or endoscopic management.

  7. Acute Ischemia Induced by High-Density Culture Increases Cytokine Expression and Diminishes the Function and Viability of Highly Purified Human Islets of Langerhans.

    Science.gov (United States)

    Smith, Kate E; Kelly, Amy C; Min, Catherine G; Weber, Craig S; McCarthy, Fiona M; Steyn, Leah V; Badarinarayana, Vasudeo; Stanton, J Brett; Kitzmann, Jennifer P; Strop, Peter; Gruessner, Angelika C; Lynch, Ronald M; Limesand, Sean W; Papas, Klearchos K

    2017-11-01

    Encapsulation devices have the potential to enable cell-based insulin replacement therapies (such as human islet or stem cell-derived β cell transplantation) without immunosuppression. However, reasonably sized encapsulation devices promote ischemia due to high β cell densities creating prohibitively large diffusional distances for nutrients. It is hypothesized that even acute ischemic exposure will compromise the therapeutic potential of cell-based insulin replacement. In this study, the acute effects of high-density ischemia were investigated in human islets to develop a detailed profile of early ischemia induced changes and targets for intervention. Human islets were exposed in a pairwise model simulating high-density encapsulation to normoxic or ischemic culture for 12 hours, after which viability and function were measured. RNA sequencing was conducted to assess transcriptome-wide changes in gene expression. Islet viability after acute ischemic exposure was reduced compared to normoxic culture conditions (P < 0.01). Insulin secretion was also diminished, with ischemic β cells losing their insulin secretory response to stimulatory glucose levels (P < 0.01). RNA sequencing revealed 657 differentially expressed genes following ischemia, with many that are associated with increased inflammatory and hypoxia-response signaling and decreased nutrient transport and metabolism. In order for cell-based insulin replacement to be applied as a treatment for type 1 diabetes, oxygen and nutrient delivery to β cells will need to be maintained. We demonstrate that even brief ischemic exposure such as would be experienced in encapsulation devices damages islet viability and β cell function and leads to increased inflammatory signaling.

  8. The impact of allogenic blood transfusion on the outcomes of total pancreatectomy with islet autotransplantation.

    Science.gov (United States)

    Yoshimatsu, Gumpei; Shahbazov, Rauf; Saracino, Giovanna; Lawrence, Michael C; Kim, Peter T; Onaca, Nicholas; Beecherl, Ernest E; Naziruddin, Bashoo; Levy, Marlon F

    2017-11-01

    Allogenic blood transfusion (ABT) may be needed for severe bleeding during total pancreatectomy with autotransplantation (TPIAT), but may induce inflammation. This study investigated the impact of ABT. With a population of 83 patients who underwent TPIAT from 2006 to 2014, this study compared cytokine levels, patient characteristics, islet characteristics, metabolic outcomes, insulin requirements, and hemoglobin A1c for those who received a blood transfusion (BT) versus no blood transfusion (NBT). Initially, proinflammatory cytokines were moderately higher in the BT group than the NBT group. Despite longer procedures and more severe bleeding, the BT group had similar values to the NBT group for insulin requirements, serum C-peptide, hemoglobin A1c, and insulin independence rate. The probability of insulin independence was slightly higher in patients receiving ≥3 units of blood. ABT induced elevation of proinflammatory cytokines during the perioperative period in TPIAT, but these changes did not significantly change posttransplant islet function. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Imatinib prevents beta cell death in vitro but does not improve islet transplantation outcome.

    Science.gov (United States)

    King, Aileen J F; Griffiths, Lisa A; Persaud, Shanta J; Jones, Peter M; Howell, Simon L; Welsh, Nils

    2016-05-01

    Introduction Improving islet transplantation outcome could not only bring benefits to individual patients but also widen the patient pool to which this life-changing treatment is available. Imatinib has previously been shown to protect beta cells from apoptosis in a variety of in vitro and in vivo models. The aim of this study was to investigate whether imatinib could be used to improve islet transplantation outcome. Methods Islets were isolated from C57Bl/6 mice and pre-cultured with imatinib prior to exposure to streptozotocin and cytokines in vitro. Cell viability and glucose-induced insulin secretion were measured. For transplantation experiments, islets were pre-cultured with imatinib for either 72 h or 24 h prior to transplantation into streptozotocin-diabetic C57Bl/6 mice. In one experimental series mice were also administered imatinib after islet transplantation. Results Imatinib partially protected islets from beta cell death in vitro. However, pre-culturing islets in imatinib or administering the drug to the mice in the days following islet transplantation did not improve blood glucose concentrations more than control-cultured islets. Conclusion Although imatinib protected against beta cell death from cytokines and streptozotocin in vitro, it did not significantly improve syngeneic islet transplantation outcome.

  10. Transplantation of islet allografts and xenografts in totally pancreatectomized diabetic dogs using the hybrid artificial pancreas.

    Science.gov (United States)

    Monaco, A P; Maki, T; Ozato, H; Carretta, M; Sullivan, S J; Borland, K M; Mahoney, M D; Chick, W L; Muller, T E; Wolfrum, J

    1991-01-01

    Previously the authors reported on a Hybrid Artificial Pancreas device that maintained patent vascular anastomoses in normal dogs and, when seeded with allogeneic canine islets, maintained normal fasting blood sugars (FBS) in diabetic pancreatectomized dogs. Eventual failure of these devices was believed to be related to loss of islet viability and/or insufficient islet mass. The current study evaluates the effect of increased islet mass produced by implantation of two islet-seeded devices in pancreatectomized dogs and compares the results with those from dogs that received a single device. Twelve of fifteen dogs receiving single devices showed initial function as determined by elimination or reduction of exogenous insulin requirement; four showed initial function and seven showed extended function (100 to 284 days). Excessive weight loss (more than 20%), despite normal FBS and insulin dependence, required that four animals in this latter group be killed. Devices seeded with xenogeneic islets have met with limited success. One dog that received two bovine islet-seeded devices achieved function for more than 100 days; the remaining bovine-seeded devices (n = 8) functioned for only 3 to 16 days. Porcine islet-seeded devices were assessed by intravenous glucose tolerance tests (IVGTT). Recipients of two devices seeded with allogeneic islets demonstrated improved IVGTT results when compared to those from pancreatectomized dogs and recipients of single devices but were abnormal when compared to intact animals. Histologic examination of device and autopsy material from all failed experiments was performed and showed no mononuclear cell infiltration of the islet chamber or vascular graft material, only a few incidence of device thrombosis, and varying degrees of islet viability as judged by morphologic and immunohistochemical evaluation. The authors believe they have demonstrated progress toward the development and clinical applicability of the Hybrid Artificial Pancreas

  11. Intranasal Insulin Restores Metabolic Parameters and Insulin Sensitivity in Rats with Metabolic Syndrome.

    Science.gov (United States)

    Derkach, K V; Ivantsov, A O; Chistyakova, O V; Sukhov, I B; Buzanakov, D M; Kulikova, A A; Shpakov, A O

    2017-06-01

    We studied the effect of 10-week treatment with intranasal insulin (0.5 IU/day) on glucose tolerance, glucose utilization, lipid metabolism, functions of pancreatic β cells, and insulin system in the liver of rats with cafeteria diet-induced metabolic syndrome. The therapy reduced body weight and blood levels of insulin, triglycerides, and atherogenic cholesterol that are typically increased in metabolic syndrome, normalized glucose tolerance and its utilization, and increased activity of insulin signaling system in the liver, thus reducing insulin resistance. The therapy did not affect the number of pancreatic islets and β cells. The study demonstrates prospects of using intranasal insulin for correction of metabolic parameters and reduction of insulin resistance in metabolic syndrome.

  12. Direct long-term effects of L-asparaginase on rat and human pancreatic islets

    DEFF Research Database (Denmark)

    Clausen, Niels; Nielsen, Jens Høiriis

    1989-01-01

    L-Asparaginase, an effective agent in the treatment of acute lymphoblastic leukemia, may induce a diabetic state. The pathogenesis of the diabetogenic effect was studied in cultured pancreatic islets. Mean serum concentrations in three children with acute lymphoblastic leukemia were 2.4 U/mL (range...... the glucagon content was unchanged. Removal of the drug resulted in partial recovery of the insulin secretion. To elucidate the mechanisms of of action of the drug, insulin biosynthesis was studied in islets cultured in asparagine-free medium with or without asparaginase. No difference in biosynthesis was seen...... between media with or without asparagine, whereas 0.1 U/mL asparaginase caused about a 50% reduction under both conditions.(ABSTRACT TRUNCATED AT 250 WORDS)...

  13. The Peri-islet Basement Membrane, a Barrier to Infiltrating Leukocytes in Type 1 Diabetes in Mouse and Human

    DEFF Research Database (Denmark)

    Korpos, Eva; Kadri, Nadir; Kappelhoff, Reinhild

    2013-01-01

    We provide the first comprehensive analysis of the extracellular matrix (ECM) composition of peri-islet capsules, composed of the peri-islet basement membrane (BM) and subjacent interstitial matrix (IM), in development of type 1 diabetes in NOD mice and in human type 1 diabetes. Our data demonstr...... IM are reconstituted once inflammation subsides, indicating that the peri-islet BM-producing cells are not lost due to the inflammation, which has important ramifications to islet transplantation studies.......We provide the first comprehensive analysis of the extracellular matrix (ECM) composition of peri-islet capsules, composed of the peri-islet basement membrane (BM) and subjacent interstitial matrix (IM), in development of type 1 diabetes in NOD mice and in human type 1 diabetes. Our data...... demonstrate global loss of peri-islet BM and IM components only at sites of leukocyte infiltration into the islet. Stereological analyses reveal a correlation between incidence of insulitis and the number of islets showing loss of peri-islet BM versus islets with intact BMs, suggesting that leukocyte...

  14. Islet β cell failure in type 2 diabetes

    Science.gov (United States)

    Prentki, Marc; Nolan, Christopher J.

    2006-01-01

    The major focus of this Review is on the mechanisms of islet β cell failure in the pathogenesis of obesity-associated type 2 diabetes (T2D). As this demise occurs within the context of β cell compensation for insulin resistance, consideration is also given to the mechanisms involved in the compensation process, including mechanisms for expansion of β cell mass and for enhanced β cell performance. The importance of genetic, intrauterine, and environmental factors in the determination of “susceptible” islets and overall risk for T2D is reviewed. The likely mechanisms of β cell failure are discussed within the two broad categories: those with initiation and those with progression roles. PMID:16823478

  15. Tiam1/Vav2-Rac1 axis: A tug-of-war between islet function and dysfunction.

    Science.gov (United States)

    Kowluru, Anjaneyulu

    2017-05-15

    Glucose-stimulated insulin secretion [GSIS] from the islet β-cell involves a well-orchestrated interplay between metabolic and cationic events. It is well established that intracellular generation of adenine and guanine nucleotide triphosphates [e.g., ATP and GTP] represents one of the requisite signaling steps in GSIS. The small molecular mass GTP-binding proteins [G-proteins; e.g., Rac1 and Cdc42] have been shown to regulate islet β-cell function including actin cytoskeletal remodeling and fusion of insulin granules with the plasma membrane for GSIS to occur. In this context, several regulatory factors for these G-proteins have been identified in the pancreatic β-cell; these include guanine nucleotide exchange factors [GEFs] and guanine nucleotide dissociation inhibitors [GDI]. Recent pharmacological and molecular biological evidence identified Tiam1 and Vav2 as GEFs for Rac1 in promoting physiological insulin secretion. Paradoxically, emerging evidence in multiple cell types, including the islet β-cell, suggests key roles for Rac1 in the onset of cellular dysfunction under conditions of metabolic stress and diabetes. Furthermore, functional inactivation of either Tiam1 or Vav2 appears to attenuate sustained activation of Rac1 and its downstream signaling events [activation of stress kinases] under conditions of metabolic stress. Together, these findings suggest both "friendly" and "non-friendly" roles for Tiam1/Vav2-Rac1 signaling axis in islet β-cell in health and diabetes. Our current understanding of the field and the knowledge gaps that exist in this area of islet biology are heighted herein. Furthermore, potential caveats in the specificity and selectivity of pharmacological inhibitors that are available currently are discussed in this Commentary. Published by Elsevier Inc.

  16. Suppression of the Nuclear Factor Eny2 Increases Insulin Secretion in Poorly Functioning INS-1E Insulinoma Cells

    Directory of Open Access Journals (Sweden)

    P. Dames

    2012-01-01

    Full Text Available Eny2, the mammalian ortholog of yeast Sus1 and drosophila E(y2, is a nuclear factor that participates in several steps of gene transcription and in mRNA export. We had previously found that Eny2 expression changes in mouse pancreatic islets during the metabolic adaptation to pregnancy. We therefore hypothesized that the protein contributes to the regulation of islet endocrine cell function and tested this hypothesis in rat INS-1E insulinoma cells. Overexpression of Eny2 had no effect but siRNA-mediated knockdown of Eny2 resulted in markedly increased glucose and exendin-4-induced insulin secretion from otherwise poorly glucose-responsive INS-1E cells. Insulin content, cellular viability, and the expression levels of several key components of glucose sensing remained unchanged; however glucose-dependent cellular metabolism was higher after Eny2 knockdown. Suppression of Eny2 enhanced the intracellular incretin signal downstream of cAMP. The use of specific cAMP analogues and pathway inhibitors primarily implicated the PKA and to a lesser extent the EPAC pathway. In summary, we identified a potential link between the nuclear protein Eny2 and insulin secretion. Suppression of Eny2 resulted in increased glucose and incretin-induced insulin release from a poorly glucose-responsive INS-1E subline. Whether these findings extend to other experimental conditions or to in vivo physiology needs to be determined in further studies.

  17. Proinsulin maturation disorder is a contributor to the defect of subsequent conversion to insulin in {beta}-cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jie, E-mail: jie.wang2@osumc.edu [Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, The Ohio State University, Columbus, OH (United States); Osei, Kwame [Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, The Ohio State University, Columbus, OH (United States)

    2011-07-22

    Highlights: {yields} Primary proinsulin maturation disorder is inherent in Ins2{sup +/Akita} islets/{beta}-cells. {yields} A consequence is the inefficient conversion of proinsulin to insulin. {yields} Post-translational defects occur as well in the involved PC1/3 and PC2 convertases. {yields} Proinsulin maturation chaos results in defects in the following conversion process. {yields} A link of the proinsulin maturation disorder and hyperproinsulinemia is suggested. -- Abstract: Disproportionate hyperproinsulinemia is an indicator of {beta}-cell dysfunction in diabetes and the basis underlying this abnormality remains obscure. Recently, we have found proinsulin is an aggregation-prone molecule inherent with a low relative folding rate and maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) in normal {beta}-cells as a result of the integration of maturation and disposal processes. PIHO is susceptible to environmental and genetic influences. Perturbation of PIHO produces a number of toxic consequences with known association to {beta}-cell failure in diabetes. To explore whether the perturbation of PIHO has a link to disproportionate hyperproinsulinemia, we investigated proinsulin conversion and the involved prohormone convertase 1/3 (PC1/3) and 2 (PC2) in mouse Ins2{sup +/Akita} islets/{beta}-cells that preserve a primary PIHO disorder due to a mutation (C96Y) in the insulin 2 (Ins2) gene. Our metabolic-labeling studies found an increased ratio of proinsulin to insulin in the cellular or released proteins of Ins2{sup +/Akita} islets. Histological, metabolic-labeling, and RT-PCR analyses revealed decreases of the PC1/3 and PC2 immunoreactivities in the {beta}-cells of Ins2{sup +/Akita} islets in spite of no declines of these two convertases at the transcriptional and translational levels. Immunoblot analyses in cloned Ins2{sup +/Akita} {beta}-cells further confirmed the increased ratio of proinsulin

  18. Proinsulin maturation disorder is a contributor to the defect of subsequent conversion to insulin in β-cells

    International Nuclear Information System (INIS)

    Wang, Jie; Osei, Kwame

    2011-01-01

    Highlights: → Primary proinsulin maturation disorder is inherent in Ins2 +/Akita islets/β-cells. → A consequence is the inefficient conversion of proinsulin to insulin. → Post-translational defects occur as well in the involved PC1/3 and PC2 convertases. → Proinsulin maturation chaos results in defects in the following conversion process. → A link of the proinsulin maturation disorder and hyperproinsulinemia is suggested. -- Abstract: Disproportionate hyperproinsulinemia is an indicator of β-cell dysfunction in diabetes and the basis underlying this abnormality remains obscure. Recently, we have found proinsulin is an aggregation-prone molecule inherent with a low relative folding rate and maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) in normal β-cells as a result of the integration of maturation and disposal processes. PIHO is susceptible to environmental and genetic influences. Perturbation of PIHO produces a number of toxic consequences with known association to β-cell failure in diabetes. To explore whether the perturbation of PIHO has a link to disproportionate hyperproinsulinemia, we investigated proinsulin conversion and the involved prohormone convertase 1/3 (PC1/3) and 2 (PC2) in mouse Ins2 +/Akita islets/β-cells that preserve a primary PIHO disorder due to a mutation (C96Y) in the insulin 2 (Ins2) gene. Our metabolic-labeling studies found an increased ratio of proinsulin to insulin in the cellular or released proteins of Ins2 +/Akita islets. Histological, metabolic-labeling, and RT-PCR analyses revealed decreases of the PC1/3 and PC2 immunoreactivities in the β-cells of Ins2 +/Akita islets in spite of no declines of these two convertases at the transcriptional and translational levels. Immunoblot analyses in cloned Ins2 +/Akita β-cells further confirmed the increased ratio of proinsulin to insulin despite the levels of PC1/3 and PC2 proteins were not reduced

  19. Intraocular in vivo imaging of pancreatic islet cell physiology/pathology

    Directory of Open Access Journals (Sweden)

    Ingo B. Leibiger

    2017-09-01

    Major conclusions: Data provided by us and others demonstrate the high versatility of this imaging platform. The use of ‘reporter islets’ engrafted in the eye, reporting on the status of in situ endogenous islets in the pancreas of the same animal, allows the identification of key-events in the development and progression of diabetes. This will not only serve as a versatile research tool but will also lay the foundation for a personalized medicine approach and will serve as a screening platform for new drugs and/or treatment protocols. ‘Metabolic’ islet transplantation, in which islets engrafted in the eye replace the endogenous beta cells, will allow for the establishment of islet-specific transgenic models and ‘humanized’ mouse models as well as serving as the basis for a new clinical transplantation site for the cure of diabetes.

  20. A rapid radioimmunoassay for insulin suitable for testing pancreatic tissue prior to transplantation

    International Nuclear Information System (INIS)

    Besch, W.; Kohnert, K.-D.; Hahn, H.-J.; Ziegler, M.; Lorenz, D.

    1984-01-01

    One way of diabetes mellitus treatment is the transplantation of insulin-producing tissue. As islet or pancreas transplantation has made progress, testing of the tissue for its vitality, insulin content and insulin secretory response prior to transplantation became necessary. Apart from problems of rejection of allografted tissue, improvement of the patients metabolic control partly depends on the insulin content of the tissue transplanted. It was the aim of the present work to establish a radioimmunoassay which ensures rapid determination of immunoreactive insulin concentrations (IRI) either intracellularly-stored or released upon stimulation of human pancreas or islet with glucose, and to demonstrate the useful application of this assay for the assessment of transplantable tissue. (Auth.)

  1. Cooperation between brain and islet in glucose homeostasis and diabetes

    Science.gov (United States)

    Schwartz, Michael W.; Seeley, Randy J.; Tschöp, Matthias H.; Woods, Stephen C.; Morton, Gregory J.; Myers, Martin G.; D'Alessio, David

    2014-01-01

    Although a prominent role for the brain in glucose homeostasis was proposed by scientists in the nineteenth century, research throughout most of the twentieth century focused on evidence that the function of pancreatic islets is both necessary and sufficient to explain glucose homeostasis, and that diabetes results from defects of insulin secretion, action or both. However, insulin-independent mechanisms, referred to as ‘glucose effectiveness’, account for roughly 50% of overall glucose disposal, and reduced glucose effectiveness also contributes importantly to diabetes pathogenesis. Although mechanisms underlying glucose effectiveness are poorly understood, growing evidence suggests that the brain can dynamically regulate this process in ways that improve or even normalize glycaemia in rodent models of diabetes. Here we present evidence of a brain-centred glucoregulatory system (BCGS) that can lower blood glucose levels via both insulin-dependent and -independent mechanisms, and propose a model in which complex and highly coordinated interactions between the BCGS and pancreatic islets promote normal glucose homeostasis. Because activation of either regulatory system can compensate for failure of the other, defects in both may be required for diabetes to develop. Consequently, therapies that target the BCGS in addition to conventional approaches based on enhancing insulin effects may have the potential to induce diabetes remission, whereas targeting just one typically does not. PMID:24201279

  2. Calcium-antagonists and islet function. V. Effect of R33711

    Energy Technology Data Exchange (ETDEWEB)

    Malaisse, W J; Sener, A; Devis, G; Somers, G [Brussels Univ. (Belgium). Lab. of Experimental Medicine

    1976-11-01

    R33711, a new drug with presumed potent calcium-antagonistic property, was found to suppress the insulinotropic action of glucose und gliclazide but not that of theophylline. A 0.2 ..mu..M concentration of R33711 was sufficient to abolish glucose-induced insulin release. At this concentration, R33711 inhibited the net uptake of /sup 45/Ca/sup 2 +/ by isolated islets, whether in the absence or presence of either glucose or sulfonylurea. In the isolated islets, R33711 failed to affect the glucose-stimulated production of lactate, the rate of /sup 45/Ca/sup 2 +/ efflux, the inhibitory action of glucose upon such an efflux and its increase in response to theophylline. These data are compatible with the view that R33711 inhibits entry of Ca/sup 2 +/ into the B-cell and that integrity of such an inward cationic movement usually plays a permissive role in the maintenance of the Ca/sup 2 +/-dependent insulin secretory process.

  3. The isolation, purification and amino-acid sequence of insulin from the teleost fish Cottus scorpius (daddy sculpin).

    Science.gov (United States)

    Cutfield, J F; Cutfield, S M; Carne, A; Emdin, S O; Falkmer, S

    1986-07-01

    Insulin from the principal islets of the teleost fish, Cottus scorpius (daddy sculpin), has been isolated and sequenced. Purification involved acid/alcohol extraction, gel filtration, and reverse-phase high-performance liquid chromatography to yield nearly 1 mg pure insulin/g wet weight islet tissue. Biological potency was estimated as 40% compared to porcine insulin. The sculpin insulin crystallised in the absence of zinc ions although zinc is known to be present in the islets in significant amounts. Two other hormones, glucagon and pancreatic polypeptide, were copurified with the insulin, and an N-terminal sequence for pancreatic polypeptide was determined. The primary structure of sculpin insulin shows a number of sequence changes unique so far amongst teleost fish. These changes occur at A14 (Arg), A15 (Val), and B2 (Asp). The B chain contains 29 amino acids and there is no N-terminal extension as seen with several other fish. Presumably as a result of the amino acid substitutions, sculpin insulin does not readily form crystals containing zinc-insulin hexamers, despite the presence of the coordinating B10 His.

  4. Long-term in vivo polychlorinated biphenyl 126 exposure induces oxidative stress and alters proteomic profile on islets of Langerhans

    Science.gov (United States)

    Loiola, Rodrigo Azevedo; Dos Anjos, Fabyana Maria; Shimada, Ana Lúcia; Cruz, Wesley Soares; Drewes, Carine Cristiane; Rodrigues, Stephen Fernandes; Cardozo, Karina Helena Morais; Carvalho, Valdemir Melechco; Pinto, Ernani; Farsky, Sandra Helena

    2016-06-01

    It has been recently proposed that exposure to polychlorinated biphenyls (PCBs) is a risk factor to type 2 diabetes mellitus (DM2). We investigated this hypothesis using long-term in vivo PCB126 exposure to rats addressing metabolic, cellular and proteomic parameters. Male Wistar rats were exposed to PCB126 (0.1, 1 or 10 μg/kg of body weight/day; for 15 days) or vehicle by intranasal instillation. Systemic alterations were quantified by body weight, insulin and glucose tolerance, and blood biochemical profile. Pancreatic toxicity was measured by inflammatory parameters, cell viability and cycle, free radical generation, and proteomic profile on islets of Langerhans. In vivo PCB126 exposure enhanced the body weight gain, impaired insulin sensitivity, reduced adipose tissue deposit, and elevated serum triglycerides, cholesterol, and insulin levels. Inflammatory parameters in the pancreas and cell morphology, viability and cycle were not altered in islets of Langerhans. Nevertheless, in vivo PCB126 exposure increased free radical generation and modified the expression of proteins related to oxidative stress on islets of Langerhans, which are indicative of early β-cell failure. Data herein obtained show that long-term in vivo PCB126 exposure through intranasal route induced alterations on islets of Langerhans related to early end points of DM2.

  5. The impact of IUGR on pancreatic islet development and β-cell function.

    Science.gov (United States)

    Boehmer, Brit H; Limesand, Sean W; Rozance, Paul J

    2017-11-01

    Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function. © 2017 Society for Endocrinology.

  6. Decrease in Circulating Fatty Acids Is Associated with Islet Dysfunction in Chronically Sleep-Restricted Rats

    Directory of Open Access Journals (Sweden)

    Shanshan Zhan

    2016-12-01

    Full Text Available Previous studies have shown that sleep restriction-induced environmental stress is associated with abnormal metabolism, but the underlying mechanism is poorly understood. In the current study, we investigated the possible lipid and glucose metabolism patterns in chronically sleep-restricted rat. Without changes in food intake, body weight was decreased and energy expenditure was increased in sleep-restricted rats. The effects of chronic sleep disturbance on metabolites in serum were examined using 1H NMR metabolomics and GC-FID/MS analysis. Six metabolites (lipoproteins, triglycerides, isoleucine, valine, choline, and phosphorylcholine exhibited significant alteration, and all the fatty acid components were decreased, which suggested fatty acid metabolism was impaired after sleep loss. Moreover, increased blood glucose, reduced serum insulin, decreased glucose tolerance, and impaired glucose-stimulated insulin secretion of islets were also observed in sleep-restricted rats. The islet function of insulin secretion could be partially restored by increasing dietary fat to sleep-disturbed rats suggested that a reduction in circulating fatty acids was related to islet dysfunction under sleep deficiency-induced environmental stress. This study provides a new perspective on the relationship between insufficient sleep and lipid/glucose metabolism, which offers insights into the role of stressful challenges in a healthy lifestyle.

  7. Encapsulated Islet Transplantation: Where Do We Stand?

    Science.gov (United States)

    Vaithilingam, Vijayaganapathy; Bal, Sumeet; Tuch, Bernard E

    2017-01-01

    Transplantation of pancreatic islets encapsulated within immuno-protective microcapsules is a strategy that has the potential to overcome graft rejection without the need for toxic immunosuppressive medication. However, despite promising preclinical studies, clinical trials using encapsulated islets have lacked long-term efficacy, and although generally considered clinically safe, have not been encouraging overall. One of the major factors limiting the long-term function of encapsulated islets is the host's immunological reaction to the transplanted graft which is often manifested as pericapsular fibrotic overgrowth (PFO). PFO forms a barrier on the capsule surface that prevents the ingress of oxygen and nutrients leading to islet cell starvation, hypoxia and death. The mechanism of PFO formation is still not elucidated fully and studies using a pig model have tried to understand the host immune response to empty alginate microcapsules. In this review, the varied strategies to overcome or reduce PFO are discussed, including alginate purification, altering microcapsule geometry, modifying alginate chemical composition, co-encapsulation with immunomodulatory cells, administration of pharmacological agents, and alternative transplantation sites. Nanoencapsulation technologies, such as conformal and layer-by-layer coating technologies, as well as nanofiber, thin-film nanoporous devices, and silicone based NanoGland devices are also addressed. Finally, this review outlines recent progress in imaging technologies to track encapsulated cells, as well as promising perspectives concerning the production of insulin-producing cells from stem cells for encapsulation.

  8. On the use of [18F]DOPA as an imaging biomarker for transplanted islet mass

    International Nuclear Information System (INIS)

    Eriksson, Olof; Mintz, Akiva; Liu, Chengyang; Yu, Ming; Naji, Ali; Alavi, Abass

    2014-01-01

    Islet transplantation is being developed as a potential cure for patients with type 1 diabetes. There is a need for non-invasive imaging techniques for the quantification of transplanted islets, as current transplantation sites are associated with a substantial loss of islet viability. The dopaminergic metabolic pathway is present in the islets; therefore, we propose Fluorine-18 labeled L-3,4-dihydroxyphenylalanine ([ 18 F]DOPA) as a biomarker for transplanted islet mass. The expression of enzymes involved in the dopaminergic metabolic pathway was investigated in both native and transplanted human islets. The specific uptake of [ 18 F]DOPA in islets and immortalized beta cells was studied in vitro by selective blocking of dopa decarboxylase (DDC). Initial in vivo positron emission tomography (PET) imaging of viable subcutaneous human islets was performed using [ 18 F]DOPA. DDC and vesicular monoamine transporter 2 are co-localized with insulin in the native human pancreas, and the expression is retained after transplantation. Islet uptake of the [ 18 F]DOPA could be modulated by inhibiting DDC, indicating that the uptake followed the normal dopaminergic metabolic pathway. In vivo imaging revealed [ 18 F]DOPA uptake at the site of the functional islet graft. Based on the in vitro and in vivo results presented in this study, we propose to further validate [ 18 F]DOPA-PET as a sensitive imaging modality for imaging extrahepatically transplanted islets. (author)

  9. Protective effect of ganoderma lucidum polysaccharides on pancreatic islet in type 2 diabetes mellitus rats

    International Nuclear Information System (INIS)

    Tang Zhigang; Xue Hua; Qiao Jin; Gu Jinhua; Xu Jiliang

    2010-01-01

    Objective: To investigate the protective effects of ganoderma lucidum polysaccharides (GLPs) on pancreatic islet in T2DM rats. Method: SD rats were fed high-fat diet for 4 weeks and then were injected STZ (30 mg/kg) to induce the type 2 diabetes mellitus(T2DM). Once the T2DM model were set successfully, rats were divided into six groups randomly: the normal group (NG), diabetes mellitus group (DMG), GPLs low dosage group (GLPs-LG), GPLs middle dosage group (GLPs-MG), GLPs high dosage group (GLPs-HG) and the berberine group (BerG). They received GLPs with different dosages (200, 400, or 800 mg/kg) and berberine (30 mg/kg) continually for 10 weeks. At 10th weekend, the following indexes of rats in each group were measured respectively: blood glucose, insulin sensivity index (ISI), the contents of NO, SOD, MDA, GSH-Px, CAT in pancreas tissue. At the same time pathological change of pancreas was evaluated by hematoxylin/eosin staining and immunohistochemistry of insulin. Result: As compared with the diabetic model, the decrease of blood glucose with GLPs treatment for 10 weeks were observed. There was also notably increased antioxidant enzyme activity such as superoxide dismutase (SOD), catalase (CAT) as well as decreased MDA content in the pancreatic homogenate. Under light microscope, GLPs-HG treated T2DM showed significantly ameliorated pathological changes, increased islet area and enhanced insulin staining intensity in islets. Conclusion: GLPs has protective effect on the STZ-induced islet injury in T2DM rats through increasing antioxidant enzyme activity and reducing oxidative stress. (authors)

  10. Candidate genes expressed in human islets and their role in the pathogenesis of type 1 diabetes

    DEFF Research Database (Denmark)

    Storling, Joachim; Brorsson, Caroline Anna

    2013-01-01

    In type 1 diabetes (T1D), the insulin-producing β cells are destroyed by an immune-mediated process leading to complete insulin deficiency. There is a strong genetic component in T1D. Genes located in the human leukocyte antigen (HLA) region are the most important genetic determinants of disease......, but more than 40 additional loci are known to significantly affect T1D risk. Since most of the currently known genetic candidates have annotated immune cell functions, it is generally considered that most of the genetic susceptibility in T1D is caused by variation in genes affecting immune cell function....... Recent studies, however, indicate that most T1D candidate genes are expressed in human islets suggesting that the functions of the genes are not restricted to immune cells, but also play roles in the islets and possibly the β cells. Several candidates change expression levels within the islets following...

  11. A rapid, efficient, and economic device and method for the isolation and purification of mouse islet cells.

    Directory of Open Access Journals (Sweden)

    Yin Zongyi

    Full Text Available Rapid, efficient, and economic method for the isolation and purification of islets has been pursued by numerous islet-related researchers. In this study, we compared the advantages and disadvantages of our developed patented method with those of commonly used conventional methods (Ficoll-400, 1077, and handpicking methods. Cell viability was assayed using Trypan blue, cell purity and yield were assayed using diphenylthiocarbazone, and islet function was assayed using acridine orange/ethidium bromide staining and enzyme-linked immunosorbent assay-glucose stimulation testing 4 days after cultivation. The results showed that our islet isolation and purification method required 12 ± 3 min, which was significantly shorter than the time required in Ficoll-400, 1077, and HPU groups (34 ± 3, 41 ± 4, and 30 ± 4 min, respectively; P 1000 islets. In summary, the MCT method is a rapid, efficient, and economic method for isolating and purifying murine islet cell clumps. This method overcomes some of the shortcomings of conventional methods, showing a relatively higher quality and yield of islets within a shorter duration at a lower cost. Therefore, the current method provides researchers with an alternative option for islet isolation and should be widely generalized.

  12. Label-Free Detection of Insulin and Glucagon within Human Islets of Langerhans Using Raman Spectroscopy

    NARCIS (Netherlands)

    Hilderink, J.; Otto, Cornelis; Slump, Cornelis H.; Lenferink, Aufrid T.M.; Engelse, M.A.; van Blitterswijk, Clemens; de Koning, E.J.P.; Karperien, Hermanus Bernardus Johannes; van Apeldoorn, Aart A.

    2013-01-01

    Intrahepatic transplantation of donor islets of Langerhans is a promising therapy for patients with type 1 diabetes. It is of critical importance to accurately monitor islet quality before transplantation, which is currently done by standard histological methods that are performed off-line and

  13. Recent progress in the use and tracking of transplanted islets as a personalized treatment for type 1 diabetes

    NARCIS (Netherlands)

    Paredes-Juarez, Genaro A; de Vos, Paul; Bulte, Jeff W M

    2017-01-01

    Introduction: Type 1 diabetes mellitus (T1DM) is an autoimmune disease in which the pancreas produces insufficient amounts of insulin. T1DM patients require exogenous sources of insulin to maintain euglycemia. Transplantation of naked or microencapsulated pancreatic islets represents an alternative

  14. Immunohistochemical and morphometric study of the development of fetal and newborn rat pancreatic islets

    International Nuclear Information System (INIS)

    Badawoud, Mohammed H.

    2003-01-01

    Aim of this study is to perform a detailed morphometric immunohistochemichal study of develpment of fetal and newborn rat pancreatic islets. 24 pancreas were obtained from 19 and 21-day-old fetal rats,1 and 4-day-old newborn rats. They were fixed in a buffered neutral formalin ,dehydrated and embedded in paraplast. Sections were stained with anti-insulin antibodies. Study was performed at Department of Anatomy, King Abdul-Aziz University, Jeddah,Kingdom of Saudi Arabia, between 2001 and 2002. The volume density of B cells showed a grdual increase during the last days of gestation and a slight increase during the first 4 days after birth. All the other morphometric parameters showed a gradual increase during the last days of gestation and during the first days after birth.The B cell nuclear diameter and volume showed a slight increase after birth. B cells were stained and present in the central part of of fetal and new born islets,while the other islet cells were present in the periphery of the islets. The size of endocrine tissue, which was represented by the islet diameter, islet volume, islet volume density, total number of islet cells,number of B cells and volume density of B cells showed a progressive increase during the prenatal period. (author)

  15. The Prohormone VGF Regulates β Cell Function via Insulin Secretory Granule Biogenesis

    Directory of Open Access Journals (Sweden)

    Samuel B. Stephens

    2017-09-01

    Full Text Available The prohormone VGF is expressed in neuroendocrine and endocrine tissues and regulates nutrient and energy status both centrally and peripherally. We and others have shown that VGF-derived peptides have direct action on the islet β cell as secretagogues and cytoprotective agents; however, the endogenous function of VGF in the β cell has not been described. Here, we demonstrate that VGF regulates secretory granule formation. VGF loss-of-function studies in both isolated islets and conditional knockout mice reveal a profound decrease in stimulus-coupled insulin secretion. Moreover, VGF is necessary to facilitate efficient exit of granule cargo from the trans-Golgi network and proinsulin processing. It also functions to replenish insulin granule stores following nutrient stimulation. Our data support a model in which VGF operates at a critical node of granule biogenesis in the islet β cell to coordinate insulin biosynthesis with β cell secretory capacity.

  16. Sustained beta-cell dysfunction but normalized islet mass in aged thrombospondin-1 deficient mice.

    Directory of Open Access Journals (Sweden)

    Carl Johan Drott

    Full Text Available Pancreatic islet endothelial cells have in recent years been shown to support beta-cell mass and function by paracrine interactions. Recently, we identified an islets endothelial-specific glycoprotein, thrombospondin-1 (TSP-1, that showed to be of importance for islet angiogenesis and beta-cell function in young mice. The present study aimed to investigate long-term consequences for islet morphology and beta-cell function of TSP-1 deficiency. Islet and beta-cell mass were observed increased at 10-12 weeks of age in TSP-1 deficient mice, but were normalized before 16 weeks of age when compared to wild-type controls. Islet vascularity was normal in 10-12 and 16-week-old TSP-1 deficient animals, whereas islets of one-year-old animals lacking TSP-1 were hypervascular. Beta-cell dysfunction in TSP-1 deficient animals was present at similar magnitudes between 10-12 and 52 weeks of age, as evaluated by glucose tolerance tests. The insulin secretion capacity in vivo of islets in one-year-old TSP-1 deficient animals was only ∼15% of that in wild-type animals. Using a transplantation model, we reconstituted TSP-1 in adult TSP-deficient islets. In contrast to neonatal TSP-1 deficient islets that we previously reported to regain function after TSP-1 reconstitution, adult islets failed to recover. We conclude that TSP-1 deficiency in islets causes changing vascular and endocrine morphological alterations postnatally, but is coupled to a chronic beta-cell dysfunction. The beta-cell dysfunction induced by TSP-1 deficiency is irreversible if not substituted early in life.

  17. Hepatic steatosis after islet transplantation: Can ultrasound predict the clinical outcome? A longitudinal study in 108 patients.

    Science.gov (United States)

    Venturini, Massimo; Maffi, Paola; Querques, Giulia; Agostini, Giulia; Piemonti, Lorenzo; Sironi, Sandro; De Cobelli, Francesco; Fiorina, Paolo; Secchi, Antonio; Del Maschio, Alessandro

    2015-08-01

    Percutaneous intra-portal islet transplantation (PIPIT) is a less invasive, safer, and repeatable therapeutic option for brittle type 1 diabetes, compared to surgical pancreas transplantation. Hepatic steatosis is a consequence of the islet engraftment but it is curiously present in a limited number of patients and its meaning is controversial. The aims of this study were to assess hepatic steatosis at ultrasound (US) after PIPIT investigating its relationship with graft function and its role in predicting the clinical outcome. From 1996 to 2012, 108 patients underwent PIPIT: 83 type-1 diabetic patients underwent allo-transplantation, 25 auto-transplantation. US was performed at baseline, 6, 12, and 24 months, recording steatosis prevalence, first detection, duration, and distribution. Contemporaneously, steatotic and non-steatotic patients were compared for the following parameters: infused islet mass, insulin independence rate, β-score, C-peptide, glycated hemoglobin, exogenous insulin requirement, and fasting plasma glucose. Steatosis at US was detected in 21/108 patients, 20/83 allo-transplanted and 1/25 auto-transplanted, mostly at 6 and 12 months. Infused islet mass was significantly higher in steatotic than non-steatotic patients (IE/kg: S=10.822; NS=6138; p=0.001). Metabolically, steatotic patients had worse basal conditions, but better islet function when steatosis was first detected, after which progressive islet exhaustion, along with steatosis disappearance, was observed. Conversely, in non-steatotic patients these parameters remained stable in time. Number of re-transplantations was significantly higher in steatotic than in non-steatotic patients (1.8 vs 1.1; p=0.001). Steatosis at US seems to be related to the islet mass and local overworking activity. It precedes metabolic alterations and can predict graft dysfunction addressing to therapeutic decisions before islet exhaustion. If steatosis does not appear, no conclusion can be drawn. Copyright

  18. Islet-like cell aggregates generated from human adipose tissue derived stem cells ameliorate experimental diabetes in mice.

    Directory of Open Access Journals (Sweden)

    Vikash Chandra

    Full Text Available BACKGROUND: Type 1 Diabetes Mellitus is caused by auto immune destruction of insulin producing beta cells in the pancreas. Currently available treatments include transplantation of isolated islets from donor pancreas to the patient. However, this method is limited by inadequate means of immuno-suppression to prevent islet rejection and importantly, limited supply of islets for transplantation. Autologous adult stem cells are now considered for cell replacement therapy in diabetes as it has the potential to generate neo-islets which are genetically part of the treated individual. Adopting methods of islet encapsulation in immuno-isolatory devices would eliminate the need for immuno-suppressants. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we explore the potential of human adipose tissue derived adult stem cells (h-ASCs to differentiate into functional islet like cell aggregates (ICAs. Our stage specific differentiation protocol permit the conversion of mesodermic h-ASCs to definitive endoderm (Hnf3β, TCF2 and Sox17 and to PDX1, Ngn3, NeuroD, Pax4 positive pancreatic endoderm which further matures in vitro to secrete insulin. These ICAs are shown to produce human C-peptide in a glucose dependent manner exhibiting in-vitro functionality. Transplantation of mature ICAs, packed in immuno-isolatory biocompatible capsules to STZ induced diabetic mice restored near normoglycemia within 3-4 weeks. The detection of human C-peptide, 1155±165 pM in blood serum of experimental mice demonstrate the efficacy of our differentiation approach. CONCLUSIONS: h-ASC is an ideal population of personal stem cells for cell replacement therapy, given that they are abundant, easily available and autologous in origin. Our findings present evidence that h-ASCs could be induced to differentiate into physiologically competent functional islet like cell aggregates, which may provide as a source of alternative islets for cell replacement therapy in type 1 diabetes.

  19. Can pancreatic duct-derived progenitors be a source of islet regeneration?

    International Nuclear Information System (INIS)

    Xia, Bing; Zhan, Xiao-Rong; Yi, Ran; Yang, Baofeng

    2009-01-01

    The regenerative process of the pancreas is of interest because the main pathogenesis of diabetes mellitus is an inadequate number of insulin-producing β-cells. The functional mass of β-cells is decreased in type 1 diabetes, so replacing missing β-cells or triggering their regeneration may allow for improved type 1 diabetes treatment. Therefore, expansion of the β-cell mass from endogenous sources, either in vivo or in vitro, represents an area of increasing interest. The mechanism of islet regeneration remains poorly understood, but the identification of islet progenitor sources is critical for understanding β-cell regeneration. One potential source is the islet proper, via the dedifferentiation, proliferation, and redifferentiation of facultative progenitors residing within the islet. Neogenesis, or that the new pancreatic islets can derive from progenitor cells present within the ducts has been reported, but the existence and identity of the progenitor cells have been debated. In this review, we focus on pancreatic ductal cells, which are islet progenitors capable of differentiating into islet β-cells. Islet neogenesis, seen as budding of hormone-positive cells from the ductal epithelium, is considered to be one mechanism for normal islet growth after birth and in regeneration, and has suggested the presence of pancreatic stem cells. Numerous results support the neogenesis hypothesis, the evidence for the hypothesis in the adult comes primarily from morphological studies that have in common the production of damage to all or part of the pancreas, with consequent inflammation and repair. Although numerous studies support a ductal origin for new islets after birth, lineage-tracing experiments are considered the 'gold standard' of proof. Lineage-tracing experiments show that pancreatic duct cells act as progenitors, giving rise to new islets after birth and after injury. The identification of differentiated pancreatic ductal cells as an in vivo progenitor for

  20. Can pancreatic duct-derived progenitors be a source of islet regeneration?

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Bing [Department of Endocrinology, First Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China); Zhan, Xiao-Rong, E-mail: xiaorongzhan@sina.com [Department of Endocrinology, First Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China); Yi, Ran [Department of Endocrinology, First Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China); Yang, Baofeng [Department of Pharmacology, State Key Laboratory of Biomedicine and Pharmacology, Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China)

    2009-06-12

    The regenerative process of the pancreas is of interest because the main pathogenesis of diabetes mellitus is an inadequate number of insulin-producing {beta}-cells. The functional mass of {beta}-cells is decreased in type 1 diabetes, so replacing missing {beta}-cells or triggering their regeneration may allow for improved type 1 diabetes treatment. Therefore, expansion of the {beta}-cell mass from endogenous sources, either in vivo or in vitro, represents an area of increasing interest. The mechanism of islet regeneration remains poorly understood, but the identification of islet progenitor sources is critical for understanding {beta}-cell regeneration. One potential source is the islet proper, via the dedifferentiation, proliferation, and redifferentiation of facultative progenitors residing within the islet. Neogenesis, or that the new pancreatic islets can derive from progenitor cells present within the ducts has been reported, but the existence and identity of the progenitor cells have been debated. In this review, we focus on pancreatic ductal cells, which are islet progenitors capable of differentiating into islet {beta}-cells. Islet neogenesis, seen as budding of hormone-positive cells from the ductal epithelium, is considered to be one mechanism for normal islet growth after birth and in regeneration, and has suggested the presence of pancreatic stem cells. Numerous results support the neogenesis hypothesis, the evidence for the hypothesis in the adult comes primarily from morphological studies that have in common the production of damage to all or part of the pancreas, with consequent inflammation and repair. Although numerous studies support a ductal origin for new islets after birth, lineage-tracing experiments are considered the 'gold standard' of proof. Lineage-tracing experiments show that pancreatic duct cells act as progenitors, giving rise to new islets after birth and after injury. The identification of differentiated pancreatic ductal

  1. Data on morphometric analysis of the pancreatic islets from C57BL/6 and BALB/c mice

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    Thiago Aparecido da Silva

    2016-09-01

    Full Text Available The endocrine portion of the pancreas, which is characterized by pancreatic islets, has been widely investigated among different species. The BALB/c and C57BL/6 mice are extensively used in experimental research, and the morphometric differences in the pancreatic islets of these animals have not been evaluated so far. Thus, our data have a comparative perspective related to the morphometric analysis of area, diameters, circularity, and density of pancreatic islets from BALB/c and C57BL/6 mice. The data presented here are focused to evaluate the differences in morphology of pancreatic islets of two common laboratory mouse strains. Keywords: Pancreatic islets, Morphometry, BALB/c and C57BL/6 mice

  2. Islet transplantation as safe and efficacious method to restore glycemic control and to avoid severe hypoglycemia after donor organ failure in pancreas transplantation.

    Science.gov (United States)

    Gerber, Philipp A; Hochuli, Michel; Benediktsdottir, Bara D; Zuellig, Richard A; Tschopp, Oliver; Glenck, Michael; de Rougemont, Olivier; Oberkofler, Christian; Spinas, Giatgen A; Lehmann, Roger

    2018-01-01

    The aim of this study was to assess safety and efficacy of islet transplantation after initial pancreas transplantation with subsequent organ failure. Patients undergoing islet transplantation at our institution after pancreas organ failure were compared to a control group of patients with pancreas graft failure, but without islet transplantation and to a group receiving pancreas retransplantation. Ten patients underwent islet transplantation after initial pancreas transplantation failed and were followed for a median of 51 months. The primary end point of HbA1c islet transplantation and in all three patients in the pancreas retransplantation group, but by none of the patients in the group without retransplantation (n = 7). Insulin requirement was reduced by 50% after islet transplantation. Kidney function (eGFR) declined with a rate of -1.0 mL ± 1.2 mL/min/1.73 m 2 per year during follow-up after islet transplantation, which tended to be slower than in the group without retransplantation (P = .07). Islet transplantation after deceased donor pancreas transplant failure is a method that can safely improve glycemic control and reduce the incidence of severe hypoglycemia and thus establish similar glycemic control as after initial pancreas transplantation, despite the need of additional exogenous insulin. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Renin-angiotensin system blockers protect pancreatic islets against diet-induced obesity and insulin resistance in mice.

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    Eliete Dalla Corte Frantz

    Full Text Available BACKGROUND: The associations between obesity, hypertension and diabetes are well established, and the renin-angiotensin system (RAS may provide a link among them. The effect of RAS inhibition on type 2 diabetes is still unclear; however, RAS seems to play an important role in the regulation of the pancreas and glucose intolerance of mice fed high-fat (HF diet. METHODS: C57BL/6 mice fed a HF diet (8 weeks were treated with aliskiren (50 mg/kg/day, enalapril (30 mg/kg/day or losartan (10 mg/kg/day for 6 weeks, and the protective effects were extensively compared among groups by morphometry, stereological tools, immunostaining, Western blotting and hormonal analysis. RESULTS: All RAS inhibitors significantly attenuated the increased blood pressure in mice fed a HF diet. Treatment with enalapril, but not aliskiren or losartan, significantly attenuated body mass (BM gain, glucose intolerance and insulin resistance, improved the alpha and beta cell mass and prevented the reduction of plasma adiponectin. Furthermore, enalapril treatment improved the protein expression of the pancreatic islet Pdx1, GLUT2, ACE2 and Mas receptors. Losartan treatment showed the greatest AT2R expression. CONCLUSION: Our findings indicate that ACE inhibition with enalapril attenuated several of the deleterious effects of the HF diet. In summary, enalapril appears to be responsible for the normalization of islet morphology and function, of alpha and beta cell mass and of Pdx1 and GLUT2 expression. These protective effects of enalapril were attributed, primarily, to the reduction in body mass gain and food intake and the enhancement of the ACE2/Ang (1-7 /Mas receptor axis and adiponectin levels.

  4. Augmented β-Cell Function and Mass in Glucocorticoid-Treated Rodents Are Associated with Increased Islet Ir-β/AKT/mTOR and Decreased AMPK/ACC and AS160 Signaling

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    André O. P. Protzek

    2014-01-01

    Full Text Available Glucocorticoid (GC therapies may adversely cause insulin resistance (IR that lead to a compensatory hyperinsulinemia due to insulin hypersecretion. The increased β-cell function is associated with increased insulin signaling that has the protein kinase B (AKT substrate with 160 kDa (AS160 as an important downstream AKT effector. In muscle, both insulin and AMP-activated protein kinase (AMPK signaling phosphorylate and inactivate AS160, which favors the glucose transporter (GLUT-4 translocation to plasma membrane. Whether AS160 phosphorylation is modulated in islets from GC-treated subjects is unknown. For this, two animal models, Swiss mice and Wistar rats, were treated with dexamethasone (DEX (1 mg/kg body weight for 5 consecutive days. DEX treatment induced IR, hyperinsulinemia, and dyslipidemia in both species, but glucose intolerance and hyperglycemia only in rats. DEX treatment caused increased insulin secretion in response to glucose and augmented β-cell mass in both species that were associated with increased islet content and increased phosphorylation of the AS160 protein. Protein AKT phosphorylation, but not AMPK phosphorylation, was found significantly enhanced in islets from DEX-treated animals. We conclude that the augmented β-cell function developed in response to the GC-induced IR involves inhibition of the islet AS160 protein activity.

  5. Unaltered Prion Pathogenesis in a Mouse Model of High-Fat Diet-Induced Insulin Resistance.

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    Caihong Zhu

    Full Text Available Epidemiological, clinical, and experimental animal studies suggest a strong correlation between insulin resistance and Alzheimer's disease. In fact, type-2 diabetes is considered an important risk factor of developing Alzheimer's disease. In addition, impaired insulin signaling in the Alzheimer's disease brain may promote Aβ production, impair Aβ clearance and induce tau hyperphosphorylation, thereby leading to deterioration of the disease. The pathological prion protein, PrPSc, deposits in the form of extracellular aggregates and leads to dementia, raising the question as to whether prion pathogenesis may also be affected by insulin resistance. We therefore established high-fat diet-induced insulin resistance in tga20 mice, which overexpress the prion protein. We then inoculated the insulin-resistant mice with prions. We found that insulin resistance in tga20 mice did not affect prion disease progression, PrPSc deposition, astrogliosis or microglial activation, and had no effect on survival. Our study demonstrates that in a mouse model, insulin resistance does not significantly contribute to prion pathogenesis.

  6. Interleukin-1beta induced changes in the protein expression of rat islets: a computerized database

    DEFF Research Database (Denmark)

    Andersen, H U; Fey, S J; Larsen, Peter Mose

    1997-01-01

    as well as the intracellular mechanisms of action of interleukin 1-mediated beta-cell cytotoxicity are unknown. However, previous studies have found an association of beta-cell destruction with alterations in protein synthesis. Thus, two-dimensional (2-D) gel electrophoresis of pancreatic islet proteins...... may be an important tool facilitating studies of the molecular pathogenesis of insulin-dependent diabetes mellitus. 2-D gel electrophoresis of islet proteins may lead to (i) the determination of qualitative and quantitative changes in specific islet proteins induced by cytokines, (ii......) the determination of the effects of agents modulating cytokine action, and (iii) the identification of primary islet protein antigen(s) initiating the immune destruction of the beta-cells. Therefore, the aim of this study was to create databases (DB) of all reproducibly detectable protein spots on 10% and 15...

  7. Cinnamon extract regulates glucose transporter and insulin-signaling gene expression in mouse adipocytes.

    Science.gov (United States)

    Cao, Heping; Graves, Donald J; Anderson, Richard A

    2010-11-01

    Cinnamon extracts (CE) are reported to have beneficial effects on people with normal and impaired glucose tolerance, the metabolic syndrome, type 2 diabetes, and insulin resistance. However, clinical results are controversial. Molecular characterization of CE effects is limited. This study investigated the effects of CE on gene expression in cultured mouse adipocytes. Water-soluble CE was prepared from ground cinnamon (Cinnamomum burmannii). Quantitative real-time PCR was used to investigate CE effects on the expression of genes coding for adipokines, glucose transporter (GLUT) family, and insulin-signaling components in mouse 3T3-L1 adipocytes. CE (100 μg/ml) increased GLUT1 mRNA levels 1.91±0.15, 4.39±0.78, and 6.98±2.18-fold of the control after 2-, 4-, and 16-h treatments, respectively. CE decreased the expression of further genes encoding insulin-signaling pathway proteins including GSK3B, IGF1R, IGF2R, and PIK3R1. This study indicates that CE regulates the expression of multiple genes in adipocytes and this regulation could contribute to the potential health benefits of CE. Published by Elsevier GmbH.

  8. Use of self-collected capillary blood samples for islet autoantibody screening in relatives: a feasibility and acceptability study.

    Science.gov (United States)

    Liu, Y; Rafkin, L E; Matheson, D; Henderson, C; Boulware, D; Besser, R E J; Ferrara, C; Yu, L; Steck, A K; Bingley, P J

    2017-07-01

    To evaluate the feasibility of using self-collected capillary blood samples for islet autoantibody testing to identify risk in relatives of people with Type 1 diabetes. Participants were recruited via the observational TrialNet Pathway to Prevention study, which screens and monitors relatives of people with Type 1 diabetes for islet autoantibodies. Relatives were sent kits for capillary blood collection, with written instructions, an online instructional video link and a questionnaire. Sera from capillary blood samples were tested for autoantibodies to glutamic acid decarboxylase, islet antigen-2, insulin and zinc transporter 8. 'Successful' sample collection was defined as obtaining sufficient volume and quality to provide definitive autoantibody results, including confirmation of positive results by repeat assay. In 240 relatives who returned samples, the median (range) age was 15.5 (1-49) years and 51% were male. Of these samples, 98% were sufficient for glutamic acid decarboxylase, islet antigen-2 and zinc transporter 8 autoantibody testing and 84% for insulin autoantibody testing and complete autoantibody screen. The upper 90% confidence bound for unsuccessful collection was 4.4% for glutamic acid decarboxylase, islet antigen-2 and/or zinc transporter 8 autoantibody assays, and 19.3% for insulin autoantibodies. Despite 43% of 220 questionnaire respondents finding capillary blood collection uncomfortable or painful, 82% preferred home self-collection of capillary blood samples compared with outpatient venepuncture (90% of those aged 18 years). The perceived difficulty of collecting capillary blood samples did not affect success rate. Self-collected capillary blood sampling offers a feasible alternative to venous sampling, with the potential to facilitate autoantibody screening for Type 1 diabetes risk. © 2017 Diabetes UK.

  9. The Ia-2β intronic miRNA, miR-153, is a negative regulator of insulin and dopamine secretion through its effect on the Cacna1c gene in mice.

    Science.gov (United States)

    Xu, Huanyu; Abuhatzira, Liron; Carmona, Gilberto N; Vadrevu, Suryakiran; Satin, Leslie S; Notkins, Abner L

    2015-10-01

    miR-153 is an intronic miRNA embedded in the genes that encode IA-2 (also known as PTPRN) and IA-2β (also known as PTPRN2). Islet antigen (IA)-2 and IA-2β are major autoantigens in type 1 diabetes and are important transmembrane proteins in dense core and synaptic vesicles. miR-153 and its host genes are co-regulated in pancreas and brain. The present experiments were initiated to decipher the regulatory network between miR-153 and its host gene Ia-2β (also known as Ptprn2). Insulin secretion was determined by ELISA. Identification of miRNA targets was assessed using luciferase assays and by quantitative real-time PCR and western blots in vitro and in vivo. Target protector was also employed to evaluate miRNA target function. Functional studies revealed that miR-153 mimic suppresses both glucose- and potassium-induced insulin secretion (GSIS and PSIS, respectively), whereas miR-153 inhibitor enhances both GSIS and PSIS. A similar effect on dopamine secretion also was observed. Using miRNA target prediction software, we found that miR-153 is predicted to target the 3'UTR region of the calcium channel gene, Cacna1c. Further studies confirmed that Cacna1c mRNA and protein are downregulated by miR-153 mimics and upregulated by miR-153 inhibitors in insulin-secreting freshly isolated mouse islets, in the insulin-secreting mouse cell line MIN6 and in the dopamine-secreting cell line PC12. miR-153 is a negative regulator of both insulin and dopamine secretion through its effect on Cacna1c expression, which suggests that IA-2β and miR-153 have opposite functional effects on the secretory pathway.

  10. Insulin-secretagogue activity and cytoprotective role of the traditional antidiabetic plant Scoparia dulcis (Sweet Broomweed).

    Science.gov (United States)

    Latha, Muniappan; Pari, Leelavinothan; Sitasawad, Sandhya; Bhonde, Ramesh

    2004-09-03

    Scoparia dulcis (Sweet Broomweed) has been documented as a traditional treatment of diabetes. The administration of an aqueous extract of Scoparia dulcis at a dose of 200 mg/kg body weight significantly decreased the blood glucose with significant increase in plasma insulin level in streptozotocin diabetic rats at the end of 15 days treatment. The insulin secretagogue action of Scoparia dulcis plant extract (SPEt) was further investigated using isolated pancreatic islets from mice. SPEt at a dose of 10 microg/ml evoked 6.0 fold stimulation of insulin secretion from isolated islets indicating its insulin secretagogue activity. In addition the effect of SPEt on streptozotocin induced cell death and nitric oxide (NO) in terms of nitrite production were also examined. SPEt protected against streptozotocin- mediated cytotoxicity (88%) and NO production in rat insulinoma cell line (RINm5F). Above results suggest the glucose lowering effect of SPEt to be associated with potentiation of insulin release from pancreatic islets. Our results revealed the possible therapeutic value of Scoparia dulcis for the better control, management and prevention of diabetes mellitus progression.

  11. Pleckstrin homology-like domain family A, member 3 (PHLDA3 deficiency improves islets engraftment through the suppression of hypoxic damage.

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    Naoaki Sakata

    Full Text Available Islet transplantation is a useful cell replacement therapy that can restore the glycometabolic function of severe diabetic patients. It is known that many transplanted islets failed to engraft, and thus, new approaches for overcoming graft loss that may improve the outcome of future clinical islet transplantations are necessary. Pleckstrin homology-like domain family A, member 3 (PHLDA3 is a known suppressor of neuroendocrine tumorigenicity, yet deficiency of this gene increases islet proliferation, prevents islet apoptosis, and improves their insulin-releasing function without causing tumors. In this study, we examined the potential use of PHLDA3-deficient islets in transplantation. We observed that: 1 transplanting PHLDA3-deficient islets into diabetic mice significantly improved their glycometabolic condition, 2 the improved engraftment of PHLDA3-deficient islets resulted from increased cell survival during early transplantation, and 3 Akt activity was elevated in PHLDA3-deficient islets, especially under hypoxic conditions. Thus, we determined that PHLDA3-deficient islets are more resistant against stresses induced by islet isolation and transplantation. We conclude that use of islets with suppressed PHLDA3 expression could be a novel and promising treatment for improving engraftment and consequent glycemic control in islet transplantation.

  12. Long-Term Survival of Neonatal Porcine Islets Without Sertoli Cells in Rabbits

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    Rafael Vald and eacute;s-Gonz and aacute;lez

    2013-04-01

    Full Text Available Cell-based therapy is a promising treatment for metabolic disorders such as type-1 diabetes. Transplantation protocols have investigated several anatomical sites for cell implantation; however, some of these procedures, such as intraportal infusion, can cause organ failure or thrombosis secondarily. Bio-artificial organs could be the choice, although concerns still remain. Using a subcutaneous device, we are able to preserve neonatal porcine islets without sertoli cells in healthy New Zealand rabbits. Devices were implanted in the back of the animals underneath the skin, and after 3 months the islets were transplanted. Histology showed the presence of inflammatory cells, predominantly eosinophils; however, insulin- and glucagon-positive cell clusters were identified inside the device at different time points for at least 90 days, and porcine C-peptide was also detected during the follow-up, indicating graft functionality. We have found that our device induces the deposition of a fibrous matrix enriched in blood vessels, which forms a good place for cell grafting, and this model is probably able to induce an immunoprivileged site. Under these conditions, transplanted porcine islet cells have the capability of producing insulin and glucagon for at least three months. [Arch Clin Exp Surg 2013; 2(2.000: 101-108

  13. Tissue-specific methylation of human insulin gene and PCR assay for monitoring beta cell death.

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    Mohamed I Husseiny

    Full Text Available The onset of metabolic dysregulation in type 1 diabetes (T1D occurs after autoimmune destruction of the majority of pancreatic insulin-producing beta cells. We previously demonstrated that the DNA encoding the insulin gene is uniquely unmethylated in these cells and then developed a methylation-specific PCR (MSP assay to identify circulating beta cell DNA in streptozotocin-treated mice prior to the rise in blood glucose. The current study extends to autoimmune non-obese diabetic (NOD mice and humans, showing in NOD mice that beta cell death occurs six weeks before the rise in blood sugar and coincides with the onset of islet infiltration by immune cells, demonstrating the utility of MSP for monitoring T1D. We previously reported unique patterns of methylation of the human insulin gene, and now extend this to other human tissues. The methylation patterns of the human insulin promoter, intron 1, exon 2, and intron 2 were determined in several normal human tissues. Similar to our previous report, the human insulin promoter was unmethylated in beta cells, but methylated in all other tissues tested. In contrast, intron 1, exon 2 and intron 2 did not exhibit any tissue-specific DNA methylation pattern. Subsequently, a human MSP assay was developed based on the methylation pattern of the insulin promoter and human islet DNA was successfully detected in circulation of T1D patients after islet transplantation therapy. Signal levels of normal controls and pre-transplant samples were shown to be similar, but increased dramatically after islet transplantation. In plasma the signal declines with time but in whole blood remains elevated for at least two weeks, indicating that association of beta cell DNA with blood cells prolongs the signal. This assay provides an effective method to monitor beta cell destruction in early T1D and in islet transplantation therapy.

  14. Association of NEFA composition with insulin sensitivity and beta cell function in the Prospective Metabolism and Islet Cell Evaluation (PROMISE) cohort.

    Science.gov (United States)

    Johnston, Luke W; Harris, Stewart B; Retnakaran, Ravi; Giacca, Adria; Liu, Zhen; Bazinet, Richard P; Hanley, Anthony J

    2018-04-01

    Our aim was to determine the longitudinal associations of individual NEFA with the pathogenesis of diabetes, specifically with differences in insulin sensitivity and beta cell function over 6 years in a cohort of individuals who are at risk for diabetes. In the Prospective Metabolism and Islet Cell Evaluation (PROMISE) longitudinal cohort, 477 participants had serum NEFA measured at the baseline visit and completed an OGTT at three time points over 6 years. Outcome variables were calculated using the OGTT values. At each visit, insulin sensitivity was assessed using the HOMA2 of insulin sensitivity (HOMA2-%S) and the Matsuda index, while beta cell function was assessed using the insulinogenic index over HOMA-IR (IGI/IR) and the insulin secretion-sensitivity index-2 (ISSI-2). Generalised estimating equations were used, adjusting for time, waist, sex, ethnicity, baseline age, alanine aminotransferase (ALT) and physical activity. NEFA were analysed as both concentrations (nmol/ml) and proportions (mol%) of the total fraction. Participants' (73% female, 70% with European ancestry) insulin sensitivity and beta cell function declined by 14-21% over 6 years of follow-up. In unadjusted models, several NEFA (e.g. 18:1 n-7, 22:4 n-6) were associated with lower insulin sensitivity, however, nearly all of these associations were attenuated in fully adjusted models. In adjusted models, total NEFA, 16:0, 18:1 n-9 and 18:2 n-6 (as concentrations) were associated with 3.7-8.0% lower IGI/IR and ISSI-2, while only 20:5 n-3 (as mol%) was associated with 7.7% higher HOMA2-%S. Total NEFA concentration was a strong predictor of lower beta cell function over 6 years. Our results suggest that the association with beta cell function is due to the absolute size of the serum NEFA fraction, rather than the specific fatty acid composition.

  15. Delineation of glutamate pathways and secretory responses in pancreatic islets with ß-cell-specific abrogation of the glutamate dehydrogenase

    DEFF Research Database (Denmark)

    Vetterli, Laurene; Carobbio, Stefania; Pournourmohammadi, Shirin

    2012-01-01

    isolated from βGlud1(-/-) mice exhibited half of the response measured in control islets. The amplifying pathway, tested at stimulatory glucose concentrations in the presence of KCl and diazoxide, was markedly inhibited in βGlud1(-/-) islets. On glucose stimulation, net synthesis of glutamate from α......-ketoglutarate was impaired in GDH-deficient islets. Accordingly, glucose-induced elevation of glutamate levels observed in control islets was absent in βGlud1(-/-) islets. Parallel biochemical pathways, namely alanine and aspartate aminotransferases, could not compensate for the lack of GDH. However, the secretory response...... to glucose was fully restored by the provision of cellular glutamate when βGlud1(-/-) islets were exposed to dimethyl glutamate. This shows that permissive levels of glutamate are required for the full development of glucose-stimulated insulin secretion and that GDH plays an indispensable role...

  16. Insulin resistance and progression to type 1 diabetes in the European Nicotinamide Diabetes Intervention Trial (ENDIT)

    DEFF Research Database (Denmark)

    Bingley, Polly J; Mahon, Jeffrey L; Gale, Edwin A M

    2008-01-01

    OBJECTIVE: Insulin resistance can modulate progression to type 1 diabetes in individuals with ongoing islet autoimmunity. We wanted to see whether measures of insulin resistance improved risk assessment in islet cell antibody (ICA)-positive relatives when added to other immune and metabolic markers......-up was 4.21 years, and 105 individuals developed diabetes. Oral and intravenous glucose tolerance tests were performed at baseline; antibodies to GAD, IA-2, and insulin were determined by radioimmunoassay; and insulin resistance was estimated by homeostasis model assessment. Risk was assessed by Cox...... glucose tolerance test (P insulin resistance (HOMA2-IR) achieved only borderline significance (P = 0.06). HOMA2-IR was an independent determinant in participants with loss of FPIR (P = 0...

  17. Pancreatic islet regeneration: Therapeutic potential, unknowns and controversy

    Directory of Open Access Journals (Sweden)

    Ingrid L. Cockburn

    2015-07-01

    Full Text Available Glucose homeostasis in mammals is primarily maintained by the insulin-secreting β-cells contained within pancreas-resident islets of Langerhans. Gross disruption of this glucose regulation as a result of pancreatic dysfunction frequently results in diabetes, which is currently a major health concern in South Africa, as well as globally. For many years, researchers have realised that the pancreas, and specifically the islets of Langerhans, have a regenerative capacity, as islet mass has frequently been shown to increase following induced pancreatic injury. Given that gross β-cell loss contributes significantly to the pathogenesis of both type 1 and type 2 diabetes, endogenous pancreatic islet regeneration has been investigated extensively as a potential β-cell replacement therapy for diabetes. From the extensive research conducted on pancreatic regeneration, opposing findings and opinions have arisen as to how, and more recently even if, pancreatic regeneration occurs following induced injury. In this review, we outline and discuss the three primary mechanisms by which pancreatic regeneration is proposed to occur: neogenesis, β-cell replication and transdifferentiation. We further explain some of the advanced techniques used in pancreatic regeneration research, and conclude that despite the technologically advanced research tools available to researchers today, the mechanisms governing pancreatic regeneration may remain elusive until more powerful techniques are developed to allow for real-time, live-cell assessment of morphology and gene expression within the pancreas.

  18. Design of a vascularized synthetic poly(ethylene glycol) macroencapsulation device for islet transplantation.

    Science.gov (United States)

    Weaver, Jessica D; Headen, Devon M; Hunckler, Michael D; Coronel, Maria M; Stabler, Cherie L; García, Andrés J

    2018-07-01

    The use of immunoisolating macrodevices in islet transplantation confers the benefit of safety and translatability by containing transplanted cells within a single retrievable device. To date, there has been limited development and characterization of synthetic poly(ethylene glycol) (PEG)-based hydrogel macrodevices for islet encapsulation and transplantation. Herein, we describe a two-component synthetic PEG hydrogel macrodevice system, designed for islet delivery to an extrahepatic islet transplant site, consisting of a hydrogel core cross-linked with a non-degradable PEG dithiol and a vasculogenic outer layer cross-linked with a proteolytically sensitive peptide to promote degradation and enhance localized vascularization. Synthetic PEG macrodevices exhibited equivalent passive molecular transport to traditional microencapsulation materials (e.g., alginate) and long-term stability in the presence of proteases in vitro and in vivo, out to 14 weeks in rats. Encapsulated islets demonstrated high viability within the device in vitro and the incorporation of RGD adhesive peptides within the islet encapsulating PEG hydrogel improved insulin responsiveness to a glucose challenge. In vivo, the implementation of a vasculogenic, degradable hydrogel layer at the outer interface of the macrodevice enhanced vascular density within the rat omentum transplant site, resulting in improved encapsulated islet viability in a syngeneic diabetic rat model. These results highlight the benefits of the facile PEG platform to provide controlled presentation of islet-supportive ligands, as well as degradable interfaces for the promotion of engraftment and overall graft efficacy. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Human beta-cell precursors mature into functional insulin-producing cells in an immunoisolation device: implications for diabetes cell therapies.

    Science.gov (United States)

    Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y; Geron, Ifat; Strongin, Alex Y; Itkin-Ansari, Pamela

    2009-04-15

    Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human beta-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human beta-cells and their progenitors and (2) the engraftment of encapsulated murine beta-cells in allo- and autoimmune settings. Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary beta-cells ameliorated diabetes without stimulating a detectable T-cell response. We demonstrate for the first time that human beta-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of beta-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells.

  20. Human β-cell Precursors Mature Into Functional Insulin-producing Cells in an Immunoisolation Device: Implications for Diabetes Cell Therapies

    Science.gov (United States)

    Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y.; Geron, Ifat; Strongin, Alex Y.; Itkin-Ansari, Pamela

    2009-01-01

    Background Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human β-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human β-cells and their progenitors and (2) the engraftment of encapsulated murine β-cells in allo- and autoimmune settings. Methods Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Results Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary β-cells ameliorated diabetes without stimulating a detectable T-cell response. Conclusions We demonstrate for the first time that human β-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of β-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells. PMID:19352116

  1. Generation of high-yield insulin producing cells from human bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Jafarian, Arefeh; Taghikhani, Mohammad; Abroun, Saeid; Pourpak, Zahra; Allahverdi, Amir; Soleimani, Masoud

    2014-07-01

    Allogenic islet transplantation is a most efficient approach for treatment of diabetes mellitus. However, the scarcity of islets and long term need for an immunosuppressant limits its application. Recently, cell replacement therapies that generate of unlimited sources of β cells have been developed to overcome these limitations. In this study we have described a stage specific differentiation protocol for the generation of insulin producing islet-like clusters from human bone marrow mesenchymal stem cells (hBM-MSCs). This specific stepwise protocol induced differentiation of hMSCs into definitive endoderm, pancreatic endoderm and pancreatic endocrine cells that expressed of sox17, foxa2, pdx1, ngn3, nkx2.2, insulin, glucagon, somatostatin, pancreatic polypeptide, and glut2 transcripts respectively. In addition, immunocytochemical analysis confirmed protein expression of the above mentioned genes. Western blot analysis discriminated insulin from proinsulin in the final differentiated cells. In derived insulin producing cells (IPCs), secreted insulin and C-peptide was in a glucose dependent manner. We have developed a protocol that generates effective high-yield human IPCs from hBM-MSCs in vitro. These finding suggest that functional IPCs generated by this procedure can be used as a cell-based approach for insulin dependent diabetes mellitus.

  2. Characterisation of insulin-producing cells differentiated from tonsil derived mesenchymal stem cells.

    Science.gov (United States)

    Kim, So-Yeon; Kim, Ye-Ryung; Park, Woo-Jae; Kim, Han Su; Jung, Sung-Chul; Woo, So-Youn; Jo, Inho; Ryu, Kyung-Ha; Park, Joo-Won

    2015-01-01

    Tonsil-derived (T-) mesenchymal stem cells (MSCs) display mutilineage differentiation potential and self-renewal capacity and have potential as a banking source. Diabetes mellitus is a prevalent disease in modern society, and the transplantation of pancreatic progenitor cells or various stem cell-derived insulin-secreting cells has been suggested as a novel therapy for diabetes. The potential of T-MSCs to trans-differentiate into pancreatic progenitor cells or insulin-secreting cells has not yet been investigated. We examined the potential of human T-MSCs to trans-differentiate into pancreatic islet cells using two different methods based on β-mercaptoethanol and insulin-transferin-selenium, respectively. First, we compared the efficacy of the two methods for inducing differentiation into insulin-producing cells. We demonstrated that the insulin-transferin-selenium method is more efficient for inducing differentiation into insulin-secreting cells regardless of the source of the MSCs. Second, we compared the differentiation potential of two different MSC types: T-MSCs and adipose-derived MSCs (A-MSCs). T-MSCs had a differentiation capacity similar to that of A-MSCs and were capable of secreting insulin in response to glucose concentration. Islet-like clusters differentiated from T-MSCs had lower synaptotagmin-3, -5, -7, and -8 levels, and consequently lower secreted insulin levels than cells differentiated from A-MSCs. These results imply that T-MSCs can differentiate into functional pancreatic islet-like cells and could provide a novel, alternative cell therapy for diabetes mellitus. Copyright © 2015 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  3. Current and Future Perspectives on Alginate Encapsulated Pancreatic Islet.

    Science.gov (United States)

    Strand, Berit L; Coron, Abba E; Skjak-Braek, Gudmund

    2017-04-01

    Transplantation of pancreatic islets in immune protective capsules holds the promise as a functional cure for type 1 diabetes, also about 40 years after the first proof of principal study. The concept is simple in using semipermeable capsules that allow the ingress of oxygen and nutrients, but limit the access of the immune system. Encapsulated human islets have been evaluated in four small clinical trials where the procedure has been evaluated as safe, but lacking long-term efficacy. Host reactions toward the biomaterials used in the capsules may be one parameter limiting the long-term function of the graft in humans. The present article briefly discusses important capsule properties such as stability, permeability and biocompatibility, as well as possible strategies to overcome current challenges. Also, recent progress in capsule development as well as the production of insulin-producing cells from human stem cells that gives promising perspectives for the transplantation of encapsulated insulin-producing tissue is briefly discussed. Stem Cells Translational Medicine 2017;6:1053-1058. © 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  4. Evolution of β-Cell Replacement Therapy in Diabetes Mellitus: Islet Cell Transplantation

    Science.gov (United States)

    Jahansouz, Cyrus; Jahansouz, Cameron; Kumer, Sean C.; Brayman, Kenneth L.

    2011-01-01

    Diabetes mellitus remains one of the leading causes of morbidity and mortality worldwide. According to the Centers for Disease Control and Prevention, approximately 23.6 million people in the United States are affected. Of these individuals, 5 to 10% have been diagnosed with Type 1 diabetes mellitus (T1DM), an autoimmune disease. Although it often appears in childhood, T1DM may manifest at any age, leading to significant morbidity and decreased quality of life. Since the 1960s, the surgical treatment for diabetes mellitus has evolved to become a viable alternative to insulin administration, beginning with pancreatic transplantation. While islet cell transplantation has emerged as another potential alternative, its role in the treatment of T1DM remains to be solidified as research continues to establish it as a truly viable alternative for achieving insulin independence. In this paper, the historical evolution, procurement, current status, benefits, risks, and ongoing research of islet cell transplantation are explored. PMID:22013505

  5. Cytotoxicity of human pI 7 interleukin-1 for pancreatic islets of Langerhans

    DEFF Research Database (Denmark)

    Bendtzen, K; Mandrup-Poulsen, T; Nerup, J

    1986-01-01

    Activated mononuclear cells appear to be important effector cells in autoimmune beta cell destruction leading to insulin-dependent (type 1) diabetes mellitus. Conditioned medium from activated mononuclear cells (from human blood) is cytotoxic to isolated rat and human islets of Langerhans. This c...

  6. Islet product characteristics and factors related to successful human islet transplantation from the Collaborative Islet Transplant Registry (CITR) 1999-2010.

    Science.gov (United States)

    Balamurugan, A N; Naziruddin, B; Lockridge, A; Tiwari, M; Loganathan, G; Takita, M; Matsumoto, S; Papas, K; Trieger, M; Rainis, H; Kin, T; Kay, T W; Wease, S; Messinger, S; Ricordi, C; Alejandro, R; Markmann, J; Kerr-Conti, J; Rickels, M R; Liu, C; Zhang, X; Witkowski, P; Posselt, A; Maffi, P; Secchi, A; Berney, T; O'Connell, P J; Hering, B J; Barton, F B

    2014-11-01

    The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999-2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (pIslet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007-2010 when compared to 1999-2002 (445.4±156.8 vs. 421.3±155.4×0(3) IEQ; pIslet purity and total number of β cells significantly improved over the study period (pislets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999-2010, and these parallel improvements in clinical outcomes over the same period. © 2014 The Authors. American Journal of Transplantation Published by Wiley Periodicals, Inc. on behalf of American Society of Transplant Surgeons.

  7. Abnormal islet sphingolipid metabolism in type 1 diabetes.

    Science.gov (United States)

    Holm, Laurits J; Krogvold, Lars; Hasselby, Jane P; Kaur, Simranjeet; Claessens, Laura A; Russell, Mark A; Mathews, Clayton E; Hanssen, Kristian F; Morgan, Noel G; Koeleman, Bobby P C; Roep, Bart O; Gerling, Ivan C; Pociot, Flemming; Dahl-Jørgensen, Knut; Buschard, Karsten

    2018-04-18

    Sphingolipids play important roles in beta cell physiology, by regulating proinsulin folding and insulin secretion and in controlling apoptosis, as studied in animal models and cell cultures. Here we investigate whether sphingolipid metabolism may contribute to the pathogenesis of human type 1 diabetes and whether increasing the levels of the sphingolipid sulfatide would prevent models of diabetes in NOD mice. We examined the amount and distribution of sulfatide in human pancreatic islets by immunohistochemistry, immunofluorescence and electron microscopy. Transcriptional analysis was used to evaluate expression of sphingolipid-related genes in isolated human islets. Genome-wide association studies (GWAS) and a T cell proliferation assay were used to identify type 1 diabetes related polymorphisms and test how these affect cellular islet autoimmunity. Finally, we treated NOD mice with fenofibrate, a known activator of sulfatide biosynthesis, to evaluate the effect on experimental autoimmune diabetes development. We found reduced amounts of sulfatide, 23% of the levels in control participants, in pancreatic islets of individuals with newly diagnosed type 1 diabetes, which were associated with reduced expression of enzymes involved in sphingolipid metabolism. Next, we discovered eight gene polymorphisms (ORMDL3, SPHK2, B4GALNT1, SLC1A5, GALC, PPARD, PPARG and B4GALT1) involved in sphingolipid metabolism that contribute to the genetic predisposition to type 1 diabetes. These gene polymorphisms correlated with the degree of cellular islet autoimmunity in a cohort of individuals with type 1 diabetes. Finally, using fenofibrate, which activates sulfatide biosynthesis, we completely prevented diabetes in NOD mice and even reversed the disease in half of otherwise diabetic animals. These results indicate that islet sphingolipid metabolism is abnormal in type 1 diabetes and suggest that modulation may represent a novel therapeutic approach. The RNA expression data is

  8. Increased Arginine and Ornithine Flux in Islets of Langerhans Cultured in a Microgravity Model System

    Science.gov (United States)

    Tobin, B. W.; Sams, C. F.; Smith, S. M.

    2000-01-01

    Microgravity is associated with alterations in protein metabolism of both muscle and bone. That pancreas-derived insulin is essential to the normal maintenance of body protein balance is well known. The importance of altered endocrine pancreas function in microgravity is not yet established. We proposed to examine the influence of a microgravity model system, the High Aspect Ratio Vessel (HARV) upon islets of Langerhans from Wistar Furth rats. Islets were cultured in the HARV for 48 hr in Medium-199 and contrasted to static control islets (PLATE). Nitrogenous compounds elaborated into the media (micromoles/ml) were analyzed at 0 and 48 hr of culture and compared to PLATE with a 2-way ANOVA (HARV vs Hour).

  9. L-cysteine reversibly inhibits glucose-induced biphasic insulin secretion and ATP production by inactivating PKM2.

    Science.gov (United States)

    Nakatsu, Daiki; Horiuchi, Yuta; Kano, Fumi; Noguchi, Yoshiyuki; Sugawara, Taichi; Takamoto, Iseki; Kubota, Naoto; Kadowaki, Takashi; Murata, Masayuki

    2015-03-10

    Increase in the concentration of plasma L-cysteine is closely associated with defective insulin secretion from pancreatic β-cells, which results in type 2 diabetes (T2D). In this study, we investigated the effects of prolonged L-cysteine treatment on glucose-stimulated insulin secretion (GSIS) from mouse insulinoma 6 (MIN6) cells and from mouse pancreatic islets, and found that the treatment reversibly inhibited glucose-induced ATP production and resulting GSIS without affecting proinsulin and insulin synthesis. Comprehensive metabolic analyses using capillary electrophoresis time-of-flight mass spectrometry showed that prolonged L-cysteine treatment decreased the levels of pyruvate and its downstream metabolites. In addition, methyl pyruvate, a membrane-permeable form of pyruvate, rescued L-cysteine-induced inhibition of GSIS. Based on these results, we found that both in vitro and in MIN6 cells, L-cysteine specifically inhibited the activity of pyruvate kinase muscle isoform 2 (PKM2), an isoform of pyruvate kinases that catalyze the conversion of phosphoenolpyruvate to pyruvate. L-cysteine also induced PKM2 subunit dissociation (tetramers to dimers/monomers) in cells, which resulted in impaired glucose-induced ATP production for GSIS. DASA-10 (NCGC00181061, a substituted N,N'-diarylsulfonamide), a specific activator for PKM2, restored the tetramer formation and the activity of PKM2, glucose-induced ATP production, and biphasic insulin secretion in L-cysteine-treated cells. Collectively, our results demonstrate that impaired insulin secretion due to exposure to L-cysteine resulted from its direct binding and inactivation of PKM2 and suggest that PKM2 is a potential therapeutic target for T2D.

  10. Islet Product Characteristics and Factors Related to Successful Human Islet Transplantation From the Collaborative Islet Transplant Registry (CITR) 1999–2010

    Science.gov (United States)

    Balamurugan, A N; Naziruddin, B; Lockridge, A; Tiwari, M; Loganathan, G; Takita, M; Matsumoto, S; Papas, K; Trieger, M; Rainis, H; Kin, T; Kay, T W; Wease, S; Messinger, S; Ricordi, C; Alejandro, R; Markmann, J; Kerr-Conti, J; Rickels, M R; Liu, C; Zhang, X; Witkowski, P; Posselt, A; Maffi, P; Secchi, A; Berney, T; O’Connell, P J; Hering, B J; Barton, F B

    2014-01-01

    The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999–2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (p Islet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007–2010 when compared to 1999–2002 (445.4 ± 156.8 vs. 421.3 ± 155.4 ×103 IEQ; p Islet purity and total number of β cells significantly improved over the study period (p islets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999–2010, and these parallel improvements in clinical outcomes over the same period. PMID:25278159

  11. A Unifying Organ Model of Pancreatic Insulin Secretion.

    Directory of Open Access Journals (Sweden)

    Andrea De Gaetano

    Full Text Available The secretion of insulin by the pancreas has been the object of much attention over the past several decades. Insulin is known to be secreted by pancreatic β-cells in response to hyperglycemia: its blood concentrations however exhibit both high-frequency (period approx. 10 minutes and low-frequency oscillations (period approx. 1.5 hours. Furthermore, characteristic insulin secretory response to challenge maneuvers have been described, such as frequency entrainment upon sinusoidal glycemic stimulation; substantial insulin peaks following minimal glucose administration; progressively strengthened insulin secretion response after repeated administration of the same amount of glucose; insulin and glucose characteristic curves after Intra-Venous administration of glucose boli in healthy and pre-diabetic subjects as well as in Type 2 Diabetes Mellitus. Previous modeling of β-cell physiology has been mainly directed to the intracellular chain of events giving rise to single-cell or cell-cluster hormone release oscillations, but the large size, long period and complex morphology of the diverse responses to whole-body glucose stimuli has not yet been coherently explained. Starting with the seminal work of Grodsky it was hypothesized that the population of pancreatic β-cells, possibly functionally aggregated in islets of Langerhans, could be viewed as a set of independent, similar, but not identical controllers (firing units with distributed functional parameters. The present work shows how a single model based on a population of independent islet controllers can reproduce very closely a diverse array of actually observed experimental results, with the same set of working parameters. The model's success in reproducing a diverse array of experiments implies that, in order to understand the macroscopic behaviour of the endocrine pancreas in regulating glycemia, there is no need to hypothesize intrapancreatic pacemakers, influences between different

  12. Cloning and functional expression of a human pancreatic islet glucose-transporter cDNA

    International Nuclear Information System (INIS)

    Permutt, M.A.; Koranyi, L.; Keller, K.; Lacy, P.E.; Scharp, D.W.; Mueckler, M.

    1989-01-01

    Previous studies have suggested that pancreatic islet glucose transport is mediated by a high-K m , low-affinity facilitated transporter similar to that expressed in liver. To determine the relationship between islet and liver glucose transporters, liver-type glucose-transporter cDNA clones were isolated from a human liver cDNA library. The liver-type glucose-transporter cDNA clone hybridized to mRNA transcripts of the same size in human liver and pancreatic islet RNA. A cDNA library was prepared from purified human pancreatic islet tissue and screened with human liver-type glucose-transporter cDNA. The authors isolated two overlapping cDNA clones encompassing 2600 base pairs, which encode a pancreatic islet protein identical in sequence to that of the putative liver-type glucose-transporter protein. Xenopus oocytes injected with synthetic mRNA transcribed from a full-length cDNA construct exhibited increased uptake of 2-deoxyglucose, confirming the functional identity of the clone. These cDNA clones can now be used to study regulation of expression of the gene and to assess the role of inherited defects in this gene as a candidate for inherited susceptibility to non-insulin-dependent diabetes mellitus

  13. Current principles and practice in autologous intraportal islet transplantation: a meta-analysis of the technical considerations.

    Science.gov (United States)

    Kumar, Rohan; Chung, Wen Yuan; Dennison, Ashley Robert; Garcea, Giuseppe

    2016-04-01

    Autologous islet transplantation (IAT) following pancreatectomy is now a recognized, albeit highly specialized procedure carried out in a small number of centers worldwide. Current clinical principles and best practice with emphasis on examining the technical aspects of surgery in centers with significant IAT experience are reviewed. Literature search for studies discussing any technical aspect of pancreatectomy with intraportal IAT was included. Thirty-five papers were included; all were single-center case series. The indications, surgical approach to pancreatectomy with IAT, islet yield, static pancreas preservation prior to islet digestion, portal vein access, absolute islet infusion volumes, and portal venous pressure changes during transfusion evaluated. IAT is considered a "last resort" when alternative approaches have been exhausted. Pre-morbid histology and prior surgical drainage adversely influence islet yields and may influence the clinical decision to perform pancreatectomy and IAT. Following pancreas digestion, absolute numbers of islets recovered and smaller islet size predict rates of insulin independence following IAT. Islet volumes and portal venous pressure changes are important factors for the development of complications. Surgical access for IAT includes intra-operative, immediate or delayed infusion via an "exteriorized" vein, and radiological percutaneous approaches. Delayed infusion can be combined with pancreas preservation techniques prior to islet isolation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Abnormal islet sphingolipid metabolism in type 1 diabetes

    DEFF Research Database (Denmark)

    Holm, Laurits J; Krogvold, Lars; Hasselby, Jane P

    2018-01-01

    AIMS/HYPOTHESIS: Sphingolipids play important roles in beta cell physiology, by regulating proinsulin folding and insulin secretion and in controlling apoptosis, as studied in animal models and cell cultures. Here we investigate whether sphingolipid metabolism may contribute to the pathogenesis....... Transcriptional analysis was used to evaluate expression of sphingolipid-related genes in isolated human islets. Genome-wide association studies (GWAS) and a T cell proliferation assay were used to identify type 1 diabetes related polymorphisms and test how these affect cellular islet autoimmunity. Finally, we...... diabetes, which were associated with reduced expression of enzymes involved in sphingolipid metabolism. Next, we discovered eight gene polymorphisms (ORMDL3, SPHK2, B4GALNT1, SLC1A5, GALC, PPARD, PPARG and B4GALT1) involved in sphingolipid metabolism that contribute to the genetic predisposition to type 1...

  15. A bilaminated decellularized scaffold for islet transplantation: Structure, properties and functions in diabetic mice.

    Science.gov (United States)

    Wang, Xi; Wang, Kai; Zhang, Wei; Qiang, Ming; Luo, Ying

    2017-09-01

    Ectopic transplantation of islets provides a beta cell-replacement approach that may allow the recovery of physiological regulation of the blood sugar level in patients with Type I diabetes (T1D). In development of new extrahepatic islet transplantation protocols in support of the islet engraftment, it is pivotal to develop scaffold materials with multifaceted functions to provide beneficial microenvironment, mediate host response in favor of vascularization/islet integration and maintain long-term islet function at the transplantation site. In this study, a new composite bilaminar decellularized scaffold (CDS) was fabricated with differential structural, degradation and mechanical properties by the combination of a fast-degrading porous collagen matrix and a mechanically supportive porcine pericardium. When investigated in the epididymal fat pad in syngeneic mouse models, it was shown that CDS could serve as superior scaffolds to promote islet adhesion and viability, and islet-CDS constructs also allowed rapid reversal of the hyperglycemic condition in the host. The engraftment and effects of islets were achieved at low islet numbers, accompanied by minimal adverse tissue reactions and optimal islet integration with the surrounding fat tissue. The bioactive surface, mechanical/chemical durability and biocompatibility of the CDS may all have played important roles in facilitating the engraftment of islets. Our study provided new insights into scaffold's function in the interplay of cells, materials and host tissue and the extracellular matrix-based scaffolds have potential for clinical translation in the beta cell-replacement therapy to treat T1D. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Endothelial microparticles released by activated protein C protect beta cells through EPCR/PAR1 and annexin A1/FPR2 pathways in islets.

    Science.gov (United States)

    Kreutter, Guillaume; Kassem, Mohamad; El Habhab, Ali; Baltzinger, Philippe; Abbas, Malak; Boisrame-Helms, Julie; Amoura, Lamia; Peluso, Jean; Yver, Blandine; Fatiha, Zobairi; Ubeaud-Sequier, Geneviève; Kessler, Laurence; Toti, Florence

    2017-11-01

    Islet transplantation is associated with early ischaemia/reperfusion, localized coagulation and redox-sensitive endothelial dysfunction. In animal models, islet cytoprotection by activated protein C (aPC) restores islet vascularization and protects graft function, suggesting that aPC triggers various lineages. aPC also prompts the release of endothelial MP that bear EPCR, its specific receptor. Microparticles (MP) are plasma membrane procoagulant vesicles, surrogate markers of stress and cellular effectors. We measured the cytoprotective effects of aPC on endothelial and insulin-secreting Rin-m5f β-cells and its role in autocrine and paracrine MP-mediated cell crosstalk under conditions of oxidative stress. MP from aPC-treated primary endothelial (EC) or β-cells were applied to H 2 O 2 -treated Rin-m5f. aPC activity was measured by enzymatic assay and ROS species by dihydroethidium. The capture of PKH26-stained MP and the expression of EPCR were probed by fluorescence microscopy and apoptosis by flow cytometry. aPC treatment enhanced both annexin A1 (ANXA1) and PAR-1 expression in EC and to a lesser extent in β-cells. MP from aPC-treated EC (eM aPC ) exhibited high EPCR and annexin A1 content, protected β-cells, restored insulin secretion and were captured by 80% of β cells in a phosphatidylserine and ANXA1-dependent mechanism. eMP activated EPCR/PAR-1 and ANXA1/FPR2-dependent pathways and up-regulated the expression of EPCR, and of FPR2/ALX, the ANXA1 receptor. Cytoprotection was confirmed in H 2 O 2 -treated rat islets with increased viability (62% versus 48% H 2 O 2 ), reduced apoptosis and preserved insulin secretion in response to glucose elevation (16 versus 5 ng/ml insulin per 10 islets). MP may prove a promising therapeutic tool in the protection of transplanted islets. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  17. Genetically modified human bone marrow derived mesenchymal stem cells for improving the outcome of human islet transplantation.

    Directory of Open Access Journals (Sweden)

    Vaibhav Mundra

    Full Text Available The objective of this study was to determine the potential of human bone marrow derived mesenchymal stem cells (hBMSCs as gene carriers for improving the outcome of human islet transplantation. hBMSCs were characterized for the expression of phenotypic markers and transduced with Adv-hVEGF-hIL-1Ra to overexpress human vascular endothelial growth factor (hVEGF and human interleukin-1 receptor antagonist (hIL-1Ra. Human islets were co-cultured with hBMSCs overexpressing hVEGF and hIL-1Ra. Islet viability was determined by membrane fluorescent method and glucose stimulation test. Transduced hBMSCs and human islets were co-transplanted under the kidney capsule of NOD.Cg-Prkdc(scid Il2rg(tm1Wjl /SzJ (NSG diabetic mice and blood glucose levels were measured over time to demonstrate the efficacy of genetically modified hBMSCs. At the end of study, immunofluorescent staining of kidney section bearing islets was performed for insulin and von Willebrand Factor (vWF. hBMSCs were positive for the expression of CD73, CD90, CD105, CD146 and Stro-1 surface markers as determined by flow cytometry. Transduction of hBMSCs with adenovirus did not affect their stemness and differentiation potential as confirmed by mRNA levels of stem cell markers and adipogenic differentiation of transduced hBMSCs. hBMSCs were efficiently transduced with Adv-hVEGF-hIL-1Ra to overexpress hVEGF and hIL-1Ra. Live dead cell staining and glucose stimulation test have shown that transduced hBMSCs improved the viability of islets against cytokine cocktail. Co-transplantation of human islets with genetically modified hBMSCs improved the glycemic control of diabetic NSG mice as determined by mean blood glucose levels and intraperitoneal glucose tolerance test. Immunofluorescent staining of kidney sections was positive for human insulin and vWF. In conclusion, our results have demonstrated that hBMSCs may be used as gene carriers and nursing cells to improve the outcome of islet

  18. Immunogenicity of Anti-HLA Antibodies in Pancreas and Islet Transplantation.

    Science.gov (United States)

    Chaigne, Benjamin; Geneugelijk, Kirsten; Bédat, Benoît; Ahmed, Mohamed Alibashe; Hönger, Gideon; De Seigneux, Sophie; Demuylder-Mischler, Sandrine; Berney, Thierry; Spierings, Eric; Ferrari-Lacraz, Sylvie; Villard, Jean

    2016-11-01

    The aim of the current study was to characterize the anti-HLA antibodies before and after pancreatic islet or pancreas transplantation. We assessed the risk of anti-donor-specific antibody (DSA) sensitization in a single-center, retrospective clinical study at Geneva University Hospital. Data regarding clinical characteristics, graft outcome, HLA mismatch, donor HLA immunogenicity, and anti-HLA antibody characteristics were collected. Between January 2008 and July 2014, 18 patients received islet transplants, and 26 patients received a pancreas transplant. Eleven out of 18 patients (61.1%) in the islet group and 12 out of 26 patients (46.2%) in the pancreas group had anti-HLA antibodies. Six patients (33.3%) developed DSAs against HLA of the islets, and 10 patients (38.4%) developed DSAs against HLA of the pancreas. Most of the DSAs were at a low level. Several parameters such as gender, number of times cells were transplanted, HLA mismatch, eplet mismatch and PIRCHE-II numbers, rejection, and infection were analyzed. Only the number of PIRCHE-II was associated with the development of anti-HLA class II de novo DSAs. Overall, the development of de novo DSAs did not influence graft survival as estimated by insulin independence. Our results indicated that pretransplant DSAs at low levels do not restrict islet or pancreas transplantation [especially islet transplantation (27.8% vs. 15.4.%)]. De novo DSAs do occur at a similar rate in both pancreas and islet transplant recipients (mainly of class II), and the immunogenicity of donor HLA is a parameter that should be taken into consideration. When combined with an immunosuppressive regimen and close follow-up, development of low levels of DSAs was not found to result in reduced graft survival or graft function in the current study.

  19. Factors Influencing Quantification of in Vivo Bioluminescence Imaging: Application to Assessment of Pancreatic Islet Transplants

    Directory of Open Access Journals (Sweden)

    John Virostko

    2004-10-01

    Full Text Available The aim of this study is to determine and characterize factors influencing in vivo bioluminescence imaging (BLI and apply them to the specific application of imaging transplanted pancreatic islets. Noninvasive quantitative assessment of transplanted pancreatic islets poses a formidable challenge. Murine pancreatic islets expressing firefly luciferase were transplanted under the renal capsule or into the portal vein of nonobese diabetic–severe combined immunodeficiency mice and the bioluminescence was quantified with a cooled charge coupled device camera and digital photon image analysis. The important, but often neglected, effects of wound healing, mouse positioning, and transplantation site on bioluminescence measurements were investigated by imaging a constant emission, isotropic light-emitting bead (λ = 600 implanted at the renal or hepatic site. The renal beads emitted nearly four times more light than hepatic beads with a smaller spot size, indicating that light absorption and scatter are greatly influenced by the transplant site and must be accounted for in BLI measurements. Detected luminescence decreased with increasing angle between the mouse surface normal and optical axis. By defining imaging parameters such as postsurgical effects, animal positioning, and light attenuation as a function of transplant site, this study develops BLI as a useful imaging modality for quantitative assessment of islets post-transplantation.

  20. Feasibility of islet magnetic resonance imaging using ferumoxytol in intraportal islet transplantation.

    Science.gov (United States)

    Jin, Sang-Man; Oh, Seung-Hoon; Oh, Bae Jun; Shim, Wooyoung; Choi, Jin Myung; Yoo, Dongkyeom; Hwang, Yong Hwa; Lee, Jung Hee; Lee, Dong Yun; Kim, Jae Hyeon

    2015-06-01

    There is a clinical need for an alternative labeling agent for magnetic resonance imaging (MRI) in islet transplantation. We aimed to evaluate the feasibility of islet MRI using ferumoxytol, which is the only clinically-available ultrasmall superparamagnetic iron oxide. We compared islet function and viability of control islets and islets labeled with ferumoxytol and/or a heparin-protamine complex (HPF). Efficacy of ferumoxytol labeling was assessed in both ex vivo and in vivo models. Labeling for 48 h with HPF, but not up to 800 μg/mL ferumoxytol, deranged ex vivo islet viability and function. The T2∗ relaxation time was optimal when islets were labeled with 800 μg/mL of ferumoxytol for 48 h. Prussian blue stain, iron content assay, transmission electron microscopy (TEM) supported internalization of ferumoxytol particles. However, the labeling intensity in the ex vivo MRI of islets labeled with ferumoxytol was much weaker than that of islets labeled with ferucarbotran. In syngeneic intraportal islet transplantation, there was a correlation between the total area of visualized islets and the transplanted islet mass. In conclusion, islet MRI using ferumoxytol was feasible in terms of in vitro and in vivo efficacy and safety. However, the weak labeling efficacy is still a hurdle for the clinical application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Effects of Energy Dissipation Rate on Islets of Langerhans: Implications for Isolation and Transplantation

    Science.gov (United States)

    Shenkman, Rustin M.; Godoy-Silva, Ruben; Papas, Klearchos K.; Chalmers, Jeffrey J.

    2010-01-01

    Acute physical stresses can occur in the procurement and isolation process and potentially can contribute to islet death or malfunction upon transplantation. A contractional flow device, previously used to subject suspended cells to well-defined hydrodynamic forces, has been modified and used to assess the vulnerability of porcine islets of Langerhans to hydrodynamic forces. The flow profiles and velocity gradients in this modified device were modeled using commercial CFD software and characterized, as in previous studies, with the scalar parameter, energy dissipation rate (EDR). Porcine islets were stressed in a single pass at various stress levels (i.e., values of EDR). Membrane integrity, oxygen uptake rate, caspase 3/7 activity, and insulin release were not affected by the levels of fluid stress tested up to an EDR of 2 × 103 W/m3. Visual observation of the stressed islets suggested that cells at the islet exterior were peeled away at EDR greater than 10,000 W/m3, however, this observation could not be confirmed using image analysis software, which determined the ratio of surface perimeter to total area. The result of this study suggests an upper limit in fluid stress to which islets can be subjected. Such upper limits assist in the design and operation of future islet processing equipment and processes. PMID:19191351

  2. Rotational Transport of Islets: The Best Way for Islets to Get around?

    Directory of Open Access Journals (Sweden)

    Rupert Oberhuber

    2013-01-01

    Full Text Available Islet transplantation is a valid treatment option for patients suffering from type 1 diabetes mellitus. To assure optimal islet cell quality, specialized islet isolation facilities have been developed. Utilization of such facilities necessitates transportation of islet cells to distant institutions for transplantation. Despite its importance, a clinically feasible solution for the transport of islets has still not been established. We here compare the functionality of isolated islets from C57BL/6 mice directly after the isolation procedure as well as after two simulated transport conditions, static versus rotation. Islet cell quality was assessed using real-time live confocal microscopy. In vivo islet function after syngeneic transplantation was determined by weight and blood sugar measurements as well as by intraperitoneal glucose tolerance tests. Vascularization of islets was documented by fluorescence microscopy and immunohistochemistry. All viability parameters documented comparable cell viability in the rotary group and the group transplanted immediately after isolation. Functional parameters assessed in vivo displayed no significant difference between these two groups. Moreover, vascularization of islets was similar in both groups. In conclusion, rotary culture conditions allows the maintenance of highest islet quality for at least 15 h, which is comparable to that of freshly isolated islets.

  3. Long-term outcomes of clinical transplantation of pancreatic islets with uncontrolled donors after cardiac death: a multicenter experience in Japan.

    Science.gov (United States)

    Anazawa, T; Saito, T; Goto, M; Kenmochi, T; Uemoto, S; Itoh, T; Yasunami, Y; Kenjo, A; Kimura, T; Ise, K; Tsuchiya, T; Gotoh, M

    2014-01-01

    Pancreatic islet transplantation has emerged as an effective treatment for type 1 diabetes mellitus, but its use is limited due to an insufficient supply of cadaveric pancreata. In Japan, uncontrolled donors after cardiac death (DCD) are not deemed to be suitable for whole-organ pancreatic transplantation, and can provide a source of pancreas for islet transplantation. However, the long-term outcomes and utility of uncontrolled DCD in the clinical setting remain controversial. Here, we summarize the long-term outcomes of islet transplantation employing uncontrolled DCD as reported to the Japan Islet Transplantation Registry. Sixty-four isolations and 34 transplantations of pancreatic islets were conducted in 18 subjects with type 1 diabetes mellitus under the cover of immunosuppression with basiliximab, sirolimus, and tacrolimus. All donors were uncontrolled DCD at the time of harvesting. The mean follow-up time was 76 months. Of the 18 recipients, 8, 4, and 6 recipients received 1, 2, and 3 islet infusions, respectively. Overall graft survivals (defined as a C-peptide level ≥0.3 ng/mL) were 72.2%, 44.4%, and 22.2% at 1, 2, and 5 years, respectively, whereas the corresponding graft survivals after multiple infusions were 90.0%, 70.0%, and 30.0%, respectively. Three of these recipients achieved insulin independence in 14, 79, and 215 days. HbA1c levels and the requirement of exogenous insulin were improved before loss of graft function. All recipients became free of severe hypoglycemia unawareness, however, at least 5 of 14 patients who had graft failure experienced recurrence of severe hypoglycemia after the loss of graft function. Islet transplantation from DCD can relieve glucose instability and problems with hypoglycemia when the graft is functioning. However, islets from uncontrolled DCD may be associated with reduced long-term graft survival. Further improvements in the clinical outcome by modification of islet isolation/transplantation protocols are

  4. Morphologic and morphometric evaluation of pancreatic islets in chronic Chagas' disease

    Directory of Open Access Journals (Sweden)

    Saldanha João Carlos

    2001-01-01

    Full Text Available PURPOSE: Hyperglycemia and abnormal glucose tolerance tests observed in some patients with chronic Chagas' disease suggest the possibility of morphological changes in pancreatic islets and/or denervation. The purpose of this study was to describe the morphology and morphometry of pancreatic islets in chronic Chagas' disease. METHODS: Morphologic and computerized morphometric studies were performed in fragments of the head, body, and tail regions of the pancreas obtained at necropsies of 8 normal controls and 17 patients with chronic Chagas' disease: 8 with the digestive form (Megas and 9 with the congestive heart failure form. RESULTS: The Megas group had a larger (p < 0.05 pancreatic islet area in the tail of the pancreas (10649.3 ± 4408.8 µm² than the normal control (9481.8 ± 3242.4 µm² and congestive heart failure (9475.1 ± 2104.9 µm² groups; likewise, the density of the pancreatic islets (PI was greater (1.2 ± 0.7 vs. 0.9 ± 0.6 vs. 1.9 ± 1.0 PI/mm², respectively. In the tail region of the pancreas of patients with the Megas form, there was a significant and positive correlation (r = +0.73 between the area and density of pancreatic islets. Discrete fibrosis and leukocytic infiltrates were found in pancreatic ganglia and pancreatic islets of the patients with Chagas' disease. Trypanosoma cruzi nests were not observed in the examined sections. Individuals with the Megas form of Chagas' disease showed increased area and density of pancreatic islets in the tail of the pancreas. CONCLUSION: The observed morphometric and morphologic alterations are consistent with functional changes in the pancreas, including glycemia and insulin disturbances.

  5. The fractal spatial distribution of pancreatic islets in three dimensions: a self-avoiding growth model

    International Nuclear Information System (INIS)

    Jo, Junghyo; Periwal, Vipul; Hörnblad, Andreas; Ahlgren, Ulf; Kilimnik, German; Hara, Manami

    2013-01-01

    The islets of Langerhans, responsible for controlling blood glucose levels, are dispersed within the pancreas. A universal power law governing the fractal spatial distribution of islets in two-dimensional pancreatic sections has been reported. However, the fractal geometry in the actual three-dimensional pancreas volume, and the developmental process that gives rise to such a self-similar structure, has not been investigated. Here, we examined the three-dimensional spatial distribution of islets in intact mouse pancreata using optical projection tomography and found a power law with a fractal dimension of 2.1. Furthermore, based on two-dimensional pancreatic sections of human autopsies, we found that the distribution of human islets also follows a universal power law with a fractal dimension of 1.5 in adult pancreata, which agrees with the value previously reported in smaller mammalian pancreas sections. Finally, we developed a self-avoiding growth model for the development of the islet distribution and found that the fractal nature of the spatial islet distribution may be associated with the self-avoidance in the branching process of vascularization in the pancreas. (paper)

  6. Immunosuppressive effect of compound K on islet transplantation in an STZ-induced diabetic mouse model.

    Science.gov (United States)

    Ma, Peng-Fei; Jiang, Jie; Gao, Chang; Cheng, Pan-Pan; Li, Jia-Li; Huang, Xin; Lin, Ying-Ying; Li, Qing; Peng, Yuan-Zheng; Cai, Mei-Chun; Shao, Wei; Zhu, Qi; Han, Sai; Qin, Qing; Xia, Jun-Jie; Qi, Zhong-Quan

    2014-10-01

    Islet transplantation is a therapeutic option for type 1 diabetes, but its long-term success is limited by islet allograft survival. Many factors imperil islet survival, especially the adverse effects and toxicity due to clinical immunosuppressants. Compound (Cpd) K is a synthesized analog of highly unsaturated fatty acids from Isatis tinctoria L. (Cruciferae). Here we investigated the therapeutic effect of Cpd K in diabetic mice and found that it significantly prolonged islet allograft survival with minimal adverse effects after 10 days. Furthermore, it reduced the proportion of CD4(+) and CD8(+) T cells in spleen and lymph nodes, inhibited inflammatory cell infiltration in allografts, suppressed serum interleukin-2 and interferon-γ secretion, and increased transforming growth factor-β and Foxp3 mRNA expression. Surprisingly, Cpd K and rapamycin had a synergistic effect. Cpd K suppressed proliferation of naïve T cells by inducing T-cell anergy and promoting the generation of regulatory T cells. In addition, nuclear factor-κB signaling was also blocked. Taken together, these findings indicate that Cpd K may have a potential immunosuppressant effect on islet transplantation. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  7. Reprogramming human umbilical cord mesenchymal stromal cells to islet-like cells with the use of in vitro-synthesized pancreatic-duodenal homebox 1 messenger RNA.

    Science.gov (United States)

    Wang, Xiao Li; Hu, Pei; Guo, Xing Rong; Yan, Ding; Yuan, Yahong; Yan, Shi Rong; Li, Dong Sheng

    2014-11-01

    Human umbilical cord mesenchymal stromal cells (hUC-MSCs) hold great potential as a therapeutic candidate to treat diabetes, owing to their unlimited source and ready availability. In this study, we differentiated hUC-MSCs with in vitro-synthesized pancreatic-duodenal homebox 1 (PDX1) messenger (m)RNA into islet-like cell clusters. hUC-MSCs were confirmed by both biomarker detection and functional differentiation. In vitro-synthesized PDX1 messenger RNA can be transfected into hUC-MSCs efficiently. The upregulated expression of PDX1 protein can be detected 4 h after transfection and remains detectable for 36 h. The induction of islet-like structures was confirmed by means of morphology and dithizone staining. Reverse transcriptase-polymerase chain reaction results revealed the expression of some key pancreatic transcription factors, such as PDX1, NeuroD, NKX6.1, Glut-2 and insulin in islet-like cell clusters. Immunofluorescence analysis showed that differentiated cells express both insulin and C-peptide. Enzyme-linked immunosorbent assay analysis validated the insulin secretion of islet-like cell clusters in response to the glucose stimulation. Our results demonstrate the use of in vitro-synthesized PDX1 messenger RNA to differentiate hUC-MSCs into islet-like cells and pave the way toward the development of reprogramming and directed-differentiation methods for the expression of encoded proteins. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  8. Glucose and carbachol activate phospholipase C in digitonin-permeabilized islets

    International Nuclear Information System (INIS)

    Wolf, B.A.; Florholmen, J.; Turk, J.; McDaniel, M.L.

    1987-01-01

    Stimulation of intact islets with D-glucose, the major insulin secretagogue, or with carbachol, a muscarinic agonist, results in the accumulation of inositoltrisphosphate (IP 3 ) suggesting that activation of phospholipase C (PLC) has a major role in stimulus-secretion coupling. Carbachol activation of PLC is an example of receptor-mediated activation in islets, whereas, the mechanism of glucose activation of PLC is controversial since a glucose receptor has not been identified. They have measured PLC activity in digitonin-permeabilized islets. Islets were labeled with 3 H-inositol, permeabilized and IP 3 accumulation measured by HPLC. Carbachol, in the presence of ATP, GTP and 1 μM free Ca 2+ released two-fold more Ins 1,3,4-P 3 than control in a time-dependent manner. Glucose, under the same conditions also significantly released more Ins 1,3,4-P 3 than control. This effect was not due to metabolism of glucose nor to an effect on the IP 3 -phosphomonoesterase. Preliminary Ca 2+ -dependency studies indicate that PLC is not activated by Ca 2+ in the submicromolar range. In conclusion, these studies show that Ca 2+ does not activate PLC, and furthermore, that D-glucose may be recognized directly by PLC

  9. Role of increased insulin demand in the adaptation of the endocrine pancreas to pregnancy

    NARCIS (Netherlands)

    Nieuwenhuizen, AG; Schuiling, GA; Moes, H; Koiter, TR

    During gestation the demand for insulin increases due to a decrease in insulin sensitivity of the maternal tissues. Simultaneously, pancreatic islet-cell proliferation, as well as insulin production and secretion increase. Both phenomena appear to be caused by the actions of pregnancy hormones. We

  10. Common variant in MTNR1B associated with increased risk of type 2 diabetes and impaired early insulin secretion

    DEFF Research Database (Denmark)

    Lyssenko, Valeriya; Nagorny, Cecilia L F; Erdos, Michael R

    2009-01-01

    Genome-wide association studies have shown that variation in MTNR1B (melatonin receptor 1B) is associated with insulin and glucose concentrations. Here we show that the risk genotype of this SNP predicts future type 2 diabetes (T2D) in two large prospective studies. Specifically, the risk genotype...... was associated with impairment of early insulin response to both oral and intravenous glucose and with faster deterioration of insulin secretion over time. We also show that the MTNR1B mRNA is expressed in human islets, and immunocytochemistry confirms that it is primarily localized in beta cells in islets....... Nondiabetic individuals carrying the risk allele and individuals with T2D showed increased expression of the receptor in islets. Insulin release from clonal beta cells in response to glucose was inhibited in the presence of melatonin. These data suggest that the circulating hormone melatonin, which...

  11. G protein-coupled receptor 39 deficiency is associated with pancreatic islet dysfunction

    DEFF Research Database (Denmark)

    Holst, Birgitte; Egerod, Kristoffer L; Jin, Chunyu

    2009-01-01

    G protein-coupled receptor (GPR)-39 is a seven-transmembrane receptor expressed mainly in endocrine and metabolic tissues that acts as a Zn(++) sensor signaling mainly through the G(q) and G(12/13) pathways. The expression of GPR39 is regulated by hepatocyte nuclear factor (HNF)-1alpha and HNF-4...... tolerance both during oral and iv glucose tolerance tests, and Gpr39(-/-) mice had decreased plasma insulin response to oral glucose. Islet architecture was normal in the Gpr39 null mice, but expression of Pdx-1 and Hnf-1alpha was reduced. Isolated, perifused islets from Gpr39 null mice secreted less...

  12. The SAMP8 mouse for investigating memory and the role of insulin in the brain.

    Science.gov (United States)

    Rhea, Elizabeth M; Banks, William A

    2017-08-01

    SAMP8 mice exhibit changes that commonly occur with normal aging late in life, but do so at a much earlier age. These changes include impairments in learning and memory as early as 8months of age and so the SAMP8 is a useful model to investigate those age-related brain changes that may affect cognition. As brain insulin signaling and memory decline with aging, the SAMP8 model is useful for investigating these changes and interventions that might prevent the decline. This review will summarize the SAMP8 mouse model, highlight changes in brain insulin signaling and its role in memory, and discuss intranasal insulin delivery in investigating effects on insulin metabolism and memory in the SAMP8 mice. Published by Elsevier Inc.

  13. Islet Autoantibody Patterns in Patients With Type 2 Diabetes Aged 60 and Higher: A Cross-Sectional Study in a Chinese Hospital

    Directory of Open Access Journals (Sweden)

    Rumei Li

    2018-05-01

    Full Text Available BackgroundSome elderly citizens with a clinical diagnosis of type 2 diabetes had evidence of positive islet autoantibodies. We aimed to discover their islet autoantibody patterns and independent correlative factors that might lead to a better understanding of significance of islet autoimmunity in the progression of elderly diabetes.MethodsA total of 541 inpatients of clinically diagnosed type 2 diabetes aged 60 and over were recruited. Three islet autoantibodies including insulin autoantibody (IAA, islet cell antibody (ICA, and glutamic acid decarboxylase antibody (GADA as well as clinical and biochemical characteristics were tested and collected in Huashan Hospital. Associations between these antibodies and clinical features were analyzed by Spearman correlation and binary logistic analyses.ResultsIn our current study, total positive rate of islet autoantibodies (IAA, ICA, and GADA was 35.67% with 26.62% for individual IAA, 5.55% for ICA, and 5.91% for GADA, in elderly with type 2 diabetes. None of combinations of such autoantibodies were observed, with the exception of IAA + ICA (0.74%, n = 4, IAA + GADA (1.48%, n = 8, and ICA + GADA (0.18%, n = 1. Compared with GADA negative group, patients in positive group tended to have lower level of fasting and postprandial C peptide, fasting blood glucose (FBG, and body mass index (BMI. After adjusted for the BMI, FBG, and postprandial C peptide, fasting C peptide seemed to be an independent factor related to GADA positivity (OR = 0.52, p = 0.02. As for patients with positive IAA, they were more likely to have insulin treatment with longer duration of diabetes, higher level of BMI, and lower level of postprandial C peptide. After adjusted for the duration of diabetes, BMI, and postprandial C peptide, insulin treatment was a significant predictor for IAA positivity (OR = 5.20, p < 0.0001. Furthermore, hs-CRP was positively related to ICA positivity, and hs

  14. Impact of islet size on pancreatic islet transplantation and potential interventions to improve outcome.

    Science.gov (United States)

    Zorzi, Daria; Phan, Tammy; Sequi, Marco; Lin, Yong; Freeman, Daniel H; Cicalese, Luca; Rastellini, Cristiana

    2015-01-01

    Better results have been recently reported in clinical pancreatic islet transplantation (ITX) due mostly to improved isolation techniques and immunosuppression; however, some limitations still exist. It is known that following transplantation, 30% to 60% of the islets are lost. In our study, we have investigated 1) the role of size as a factor affecting islet engraftment and 2) potential procedural manipulations to increase the number of smaller functional islets that can be transplanted. C57/BL10 mice were used as donors and recipients in a syngeneic islet transplant model. Isolated islets were divided by size (large, >300 μm; medium 150-300 μm; small, <150 μm). Each size was transplanted in chemically induced diabetic mice as full (600 IEQ), suboptimal (400 IEQ), and marginal mass (200 IEQ). Control animals received all size islets. Engraftment was defined as reversal of diabetes by day 7 posttransplantation. When the superiority of smaller islets was observed, strategies of overdigestion and fragmentation were adopted during islet isolation in the attempt to reduce islet size and improve engraftment. Smaller islets were significantly superior in engraftment compared to medium, large, and control (all sizes) groups. This was more evident when marginal mass data were compared. In all masses, success decreased as islet size increased. Once islets were engrafted, functionality was not affected by size. When larger islets were fragmented, a significant decrease in islet functionality was observed. On the contrary, if pancreata were slightly overdigested, although not as successful as small naive islets, an increase in engraftment was observed when compared to the control group. In conclusion, smaller islets are superior in engraftment following islet transplantation. Fragmentation has a deleterious effect on islet engraftment. Islet isolations can be performed by reducing islet size with slight overdigestion, and it can be safely adopted to improve clinical

  15. Rituximab selectively suppresses specific islet antibodies.

    Science.gov (United States)

    Yu, Liping; Herold, Kevan; Krause-Steinrauf, Heidi; McGee, Paula L; Bundy, Brian; Pugliese, Alberto; Krischer, Jeff; Eisenbarth, George S

    2011-10-01

    The TrialNet Study Group evaluated rituximab, a B-cell-depleting monoclonal antibody, for its effect in new-onset patients with type 1A diabetes. Rituximab decreased the loss of C-peptide over the first year of follow-up and markedly depleted B lymphocytes for 6 months after administration. This article analyzes the specific effect of rituximab on multiple islet autoantibodies. A total of 87 patients between the ages of 8 and 40 years received either rituximab or a placebo infusion weekly for four doses close to the onset of diabetes. Autoantibodies to insulin (IAAs), GAD65 (GADAs), insulinoma-associated protein 2 (IA2As), and ZnT8 (ZnT8As) were measured with radioimmunoassays. The primary outcome for this autoantibody analysis was the mean level of autoantibodies during follow-up. Rituximab markedly suppressed IAAs compared with the placebo injection but had a much smaller effect on GADAs, IA2As, and ZnT8As. A total of 40% (19 of 48) of rituximab-treated patients who were IAA positive became IAA negative versus 0 of 29 placebo-treated patients (P 1 year in insulin-treated patients. For the patients receiving insulin for >2 weeks prior to rituximab administration, we cannot assess whether rituximab not only blocks the acquisition of insulin antibodies induced by insulin administration and/or also suppresses preformed insulin autoantibodies. Studies in prediabetic non-insulin-treated patients will likely be needed to evaluate the specific effects of rituximab on levels of IAAs.

  16. Efficacy of DHMEQ, a NF-κB inhibitor, in islet transplantation: II. Induction DHMEQ treatment ameliorates subsequent alloimmune responses and permits long-term islet allograft acceptance.

    Science.gov (United States)

    Watanabe, Masaaki; Yamashita, Kenichiro; Kamachi, Hirofumi; Kuraya, Daisuke; Koshizuka, Yasuyuki; Shibasaki, Susumu; Asahi, Yoh; Ono, Hitoshi; Emoto, Shin; Ogura, Masaomi; Yoshida, Tadashi; Ozaki, Michitaka; Umezawa, Kazuo; Matsushita, Michiaki; Todo, Satoru

    2013-09-15

    Long-term graft deterioration remains a major obstacle in the success of pancreatic islet transplantation (PITx). Antigen-independent inflammatory and innate immune responses strengthen subsequent antigen-dependent immunity; further, activation of nuclear factor (NF)-κB plays a key role during these responses. In this study, we tested our hypothesis that, by the inhibition of NF-κB activation, the suppression of these early responses after PITx could facilitate graft acceptance. Full major histocompatibility complex (MHC)-mismatched BALB/c (H-2) mice islets were transplanted into streptozotocin-induced diabetic C57BL/6 (B6: H-2) mice. The NF-κB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) was administered for either 3 or 14 days after PITx. To some PITx recipients, tacrolimus was also administered. Islet allograft survival, alloimmune responses, and in vitro effects of DHMEQ on dendritic cells (DCs) were assessed. With a vehicle treatment, 600 islet allografts were promptly rejected after PITx. In contrast, 3-day treatment with DHMEQ, followed by 2-week treatment with tacrolimus, allowed permanent acceptance of islet allografts. The endogenous danger-signaling molecule high mobility group complex 1 (HMGB1) was elevated in sera shortly after PITx, whereas DHMEQ administration abolished this elevation. DHMEQ suppressed HMGB1-driven cellular activation and proinflammatory cytokine secretion in mouse bone marrow-derived DCs and significantly reduced the capacity of DCs to prime allogeneic T-cell proliferation in vitro. Finally, the DHMEQ plus tacrolimus regimen reverted the diabetic state with only 300 islet allografts. Inhibition of NF-κB activation by DHMEQ shortly after PITx suppresses HMGB1, which activates DCs and strengthens the magnitude of alloimmune responses; this permits long-term islet allograft acceptance, even in case of fewer islet allografts.

  17. Insulin-producing cells generated from dedifferentiated human pancreatic beta cells expanded in vitro.

    Directory of Open Access Journals (Sweden)

    Holger A Russ

    Full Text Available Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, attempts at expanding human islet cells in tissue culture result in loss of beta-cell phenotype. Using a lineage-tracing approach we provided evidence for massive proliferation of beta-cell-derived (BCD cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT. Epigenetic analyses indicate that key beta-cell genes maintain open chromatin structure in expanded BCD cells, although they are not transcribed. Here we investigated whether BCD cells can be redifferentiated into beta-like cells.Redifferentiation conditions were screened by following activation of an insulin-DsRed2 reporter gene. Redifferentiated cells were characterized for gene expression, insulin content and secretion assays, and presence of secretory vesicles by electron microscopy. BCD cells were induced to redifferentiate by a combination of soluble factors. The redifferentiated cells expressed beta-cell genes, stored insulin in typical secretory vesicles, and released it in response to glucose. The redifferentiation process involved mesenchymal-epithelial transition, as judged by changes in gene expression. Moreover, inhibition of the EMT effector SLUG (SNAI2 using shRNA resulted in stimulation of redifferentiation. Lineage-traced cells also gave rise at a low rate to cells expressing other islet hormones, suggesting transition of BCD cells through an islet progenitor-like stage during redifferentiation.These findings demonstrate for the first time that expanded dedifferentiated beta cells can be induced to redifferentiate in culture. The findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug

  18. High-level expression of human insulin receptor cDNA in mouse NIH 3T3 cells

    International Nuclear Information System (INIS)

    Whittaker, J.; Okamoto, A.K.; Thys, R.; Bell, G.I.; Steiner, D.F.; Hofmann, C.A.

    1987-01-01

    In order to develop a simple, efficient system for the high-level expression of human insulin receptors in eukaryotic cells, a full-length human kidney insulin receptor cDNA was inserted into a bovine papilloma virus vector under the control of the mouse metallothionein promoter. After transfection of mouse NIH 3T3 cells with this construct, seven cell lines expressing insulin receptors were isolated; two cell lines had more than 10 6 receptors per cell. The cell line with the highest 125 I-insulin binding (NIH 3T3 HIR3.5) had 6 x 10 6 receptors with a K/sub d/ of 10 -9 M. This level was not dependent on exposure to metals but could be increased further to 2 x 10 7 receptors per cell by addition of sodium butyrate to the culture medium. The α and β subunits had apparent molecular weights of 147,000 and 105,000, respectively (compared to 135,000 and 95,000 in IM-9 human lymphocytes), values identical to those of the α and β subunits of the insulin receptors of nontransformed NIH 3T3 cells. This size difference was due to altered carbohydrate composition, as N-glycanase digestion reduced the apparent receptor subunit size of the transfected cells and IM-9 lymphocytes to identical values. The alteration in N-linked oligosaccharide composition could not be ascribed to differences in the kinetics of posttranslational processing of the insulin receptors, which was comparable to that of other cells studied. The basal rate of glycogen synthesis in the cells overexpressing insulin receptors was increased 4- to 5-fold compared with controls. Low levels of added insulin (0.1 nM) caused a 50% increase in the rate of glycogen synthesis

  19. Reduced insulin exocytosis in human pancreatic β-cells with gene variants linked to type 2 diabetes

    DEFF Research Database (Denmark)

    Rosengren, Anders H; Braun, Matthias; Mahdi, Taman

    2012-01-01

    The majority of genetic risk variants for type 2 diabetes (T2D) affect insulin secretion, but the mechanisms through which they influence pancreatic islet function remain largely unknown. We functionally characterized human islets to determine secretory, biophysical, and ultrastructural features ...

  20. The Spleen as an Optimal Site for Islet Transplantation and a Source of Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Naoaki Sakata

    2018-05-01

    Full Text Available This review demonstrates the unique potential of the spleen as an optimal site for islet transplantation and as a source of mesenchymal stem cells. Islet transplantation is a cellular replacement therapy used to treat severe diabetes mellitus; however, its clinical outcome is currently unsatisfactory. Selection of the most appropriate transplantation site is a major factor affecting the clinical success of this therapy. The spleen has long been studied as a candidate site for islet transplantation. Its advantages include physiological insulin drainage and regulation of immunity, and it has recently also been shown to contribute to the regeneration of transplanted islets. However, the efficacy of transplantation in the spleen is lower than that of intraportal transplantation, which is the current representative method of clinical islet transplantation. Safer and more effective methods of islet transplantation need to be established to allow the spleen to be used for clinical transplantation. The spleen is also of interest as a mesenchymal stem cell reservoir. Splenic mesenchymal stem cells contribute to the repair of damaged tissue, and their infusion may thus be a promising therapy for autoimmune diseases, including type 1 diabetes mellitus and Sjogren’s syndrome.

  1. The Spleen as an Optimal Site for Islet Transplantation and a Source of Mesenchymal Stem Cells.

    Science.gov (United States)

    Sakata, Naoaki; Yoshimatsu, Gumpei; Kodama, Shohta

    2018-05-07

    This review demonstrates the unique potential of the spleen as an optimal site for islet transplantation and as a source of mesenchymal stem cells. Islet transplantation is a cellular replacement therapy used to treat severe diabetes mellitus; however, its clinical outcome is currently unsatisfactory. Selection of the most appropriate transplantation site is a major factor affecting the clinical success of this therapy. The spleen has long been studied as a candidate site for islet transplantation. Its advantages include physiological insulin drainage and regulation of immunity, and it has recently also been shown to contribute to the regeneration of transplanted islets. However, the efficacy of transplantation in the spleen is lower than that of intraportal transplantation, which is the current representative method of clinical islet transplantation. Safer and more effective methods of islet transplantation need to be established to allow the spleen to be used for clinical transplantation. The spleen is also of interest as a mesenchymal stem cell reservoir. Splenic mesenchymal stem cells contribute to the repair of damaged tissue, and their infusion may thus be a promising therapy for autoimmune diseases, including type 1 diabetes mellitus and Sjogren’s syndrome.

  2. Total Pancreatectomy (TP) and Islet Autotransplantation (IAT) for Chronic Pancreatitis (CP)

    Science.gov (United States)

    Sutherland, David E.R.; Radosevich, David M.; Bellin, Melena D.; Hering, Bernard J.; Beilman, Gregory J.; Dunn, Ty B.; Chinnakotla, Srinath; Vickers, Selwyn M.; Bland, Barbara; Balamurugan, A.N.; Freeman, Martin L.; Pruett, Timothy L.

    2013-01-01

    Background Total-pancreatectomy (TP) with intraportal-islet-auto-transplantation (IAT) can relieve pain and preserve beta-cell-mass in patients with chronic-pancreatitis (CP) when other-therapies fail. Reported is a >30-year-single-center-series. Study Design 409 patients (53 children, 5–18 yrs) with CP underwent TP-IAT from Feb/1977–Sept/2011; (etiology idiopathic-41%; SOD/biliary-9%; genetic-14%; divisum-17%; alcohol-7%; other-12%); mean age-35.3 yrs,); 74% female; prior-surgeries 21%--Puestow procedure 9%, Whipple 6%, distal pancreatectomy 7%; other 2%). Islet-function was classified as insulin-independent for those on no insulin; partial if known C-peptide positive or euglycemic on once-daily-insulin; and insulin-dependent if on standard basal–bolus diabetic regimen. An SF-36-survey for Quality-of-Life (QOL)) was completed before and in serial follow-up by patients done since 2007 with an integrated-survey that added in 2008. Results Actuarial-patient-survival post-TP-IAT was 96% in adults and 98% in children (1-year) and; 89% and 98% (5-years). Complications requiring relaparotomy occurred in 15.9%, bleeding (9.5%) being most common. IAT-function is achieved in 90% (C-peptide >0.6 ng/ml). At 3 years, 30% were insulin-independent (25% in adults, 55% in children) and 33% had partial-function. Mean HbA1C was 5000/kg (24%)] correlated with degree of function with insulin-independent rates at 3 yrs of 12, 22 and 72%, partial function 33, 62 and 24%. All patients had pain before TP-IAT and nearly all were on daily-narcotics. After TP-IAT, 85% had pain-improvement. By two years 59% had ceased-narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions including the Physical and Mental Component Summaries (P2/3 of patients with insulin-independence occurring in one-quarter of adults and half the children. PMID:22397977

  3. Streptozotocin Diabetes CORRELATION WITH EXTENT OF DEPRESSION OF PANCREATIC ISLET NICOTINAMIDE ADENINE DINUCLEOTIDE

    Science.gov (United States)

    Anderson, Tom; Schein, Philip S.; McMenamin, Mary G.; Cooney, David A.

    1974-01-01

    The diabetogenic activity of streptozotocin has been correlated with a reduction in pyridine nucleotide synthesis in the mouse pancreatic islet. To determine the specificity of this reduction for diabetogenicity, a comparative study of streptozotocin, its cytotoxic moiety, 1-methyl-1-nitrosourea, and alloxan was performed. Streptozotocin administered intraperitoneally (i.p.) producd a dose-related reduction in islet NAD which was proportional to the degree of diabetogenicity. A diabetogenic dose, 200 mg/kg, attained a peak plasma N-nitroso intact streptozotocin concentration of 0.224 μmol/ml and reduced the mean islet NAD from a control of 0.78 to 0.15 pmol. At borderline, 150 mg/kg, and nondiabetogenic, 100 mg/kg, doses, plasma concentrations reached 0.161 and 0.136 μmol/ml, and NAD was 0.36 and 0.86 pmol/islet, respectively. 1-Methyl-1-nitrosourea, 100 mg/kg, attained a maximum N-nitroso intact 1-methyl-1-nitrosourea concentration of 0.162 μmol/ml and reduced the mean NAD to 0.58 pmol/islet, and was nondiabetogenic; 200 mg/kg attained a peak plasma concentration of 0.344 μmol/ml and depressed NAD to 0.38 pmol/islet, and was inconsistently diabetogenic. Islet NAD of 0.4 pmol/islet or greater is required for integrity of the beta cell. A diabetogenic dose of alloxan, 500 mg/kg, did not depress NAD, 0.85 pmol/islet, therefore confirming that its mechanism of diabetogenicity differs from that of streptozotocin. In vivo uptake of [methyl-14C]streptozotocin by islets was 3.8 times that of [methyl-14C]-1-methyl-1-nitrosourea, whereas uptake by the exocrine pancreas favored 1-methyl-1-nitrosourea over streptozotocin 2.4:1. The decreased islet uptake of 1-methyl-1-nitrosourea correlates with the 3.5 times increased molar dosage required to produce islet NAD depression comparable to that of streptozotocin, 150 mg/kg. These studies indicate that the glucose carrier of streptozotocin facilitates uptake of its cytotoxic group, 1-methyl-1-nitrosourea, into islets. PMID

  4. Growth hormone and prolactin stimulate the expression of rat preadipocyte factor-1/delta-like protein in pancreatic islets

    DEFF Research Database (Denmark)

    Carlsson, C; Tornehave, D; Lindberg, Karen

    1997-01-01

    GH-induced clone had 96% identity with mouse preadipocyte factor-1 (Pref-1, or delta-like protein (Dlk)]. The size of Pref-1 messenger RNA (mRNA) in islets was 1.6 kilobases, with two less abundant mRNAs of 3.7 and 6.2 kilobases. The Pref-1 mRNA content of islets from adult rats was only 1% of that in neonatal...... islets. Pref-1 mRNA was markedly up-regulated in islets from pregnant rats from day 12 to term compared with those from age-matched female rats. Two peaks in mRNA expression were observed during gestation, one on day 14 and the other at term, whereafter it decreased to nonpregnant levels. Pref-1 m...

  5. Efficient Differentiation of Mouse Embryonic Stem Cells into Insulin-Producing Cells

    Directory of Open Access Journals (Sweden)

    Szu-Hsiu Liu

    2012-01-01

    Full Text Available Embryonic stem (ES cells are a potential source of a variety of differentiated cells for cell therapy, drug discovery, and toxicology screening. Here, we present an efficacy strategy for the differentiation of mouse ES cells into insulin-producing cells (IPCs by a two-step differentiation protocol comprising of (i the formation of definitive endoderm in monolayer culture by activin A, and (ii this monolayer endoderm being induced to differentiate into IPCs by nicotinamide, insulin, and laminin. Differentiated cells can be obtained within approximately 7 days. The differentiation IPCs combined application of RT-PCR, ELISA, and immunofluorescence to characterize phenotypic and functional properties. In our study, we demonstrated that IPCs produced pancreatic transcription factors, endocrine progenitor marker, definitive endoderm, pancreatic β-cell markers, and Langerhans α and δ cells. The IPCs released insulin in a manner that was dose dependent upon the amount of glucose added. These techniques may be able to be applied to human ES cells, which would have very important ramifications for treating human disease.

  6. Induction of tolerance and prolongation of islet allograft survival by syngeneic hematopoietic stem cell transplantation in mice.

    Science.gov (United States)

    Yang, Shi-feng; Xue, Wu-jun; Lu, Wan-hong; Xie, Li-yi; Yin, Ai-ping; Zheng, Jin; Sun, Ji-ping; Li, Yang

    2015-10-01

    Syngeneic or autologous hematopoietic stem cells transplantation (HSCT) has been proposed to treat autoimmune diseases because of its immunosuppressive and immunomodulatory effects, which can also contribute to posttransplant antirejection therapy. In this study, we explored the tolerogenic effect of syngeneic HSCT on prolonging islet allograft survival. C57BL/6 mice received syngeneic HSCT plus preconditioning with sublethal irradiation. Then islets of BALB/c mice were transplanted into the renal subcapsular of C57BL/6 mice after chemically induced into diabetes. HSCT mice exhibited improved islet allograft survival and increased serum insulin compared to control mice. Islet allografts of HSCT mice displayed lower level lymphocyte infiltration and stronger insulin staining than control mice. T cells of HSCT mice proliferated poorly in response to allogeneic splenocytes compared to control mice. Mice appeared reversed interferon-γ (IFN-γ)/interleukin-4 (IL-4) ratio to a Th2 immune deviation after syngeneic HSCT. The percentage of CD8(+) T cells was lower, while percentage of CD4(+)CD25(+)Foxp3(+) T regulatory cells (Tregs) was higher in HSCT mice than control mice. HSCT mice showed higher percentage of CTLA-4(+) T cells and expression of CTLA-4 mRNA than control mice. Targeting of CTLA-4 by intraperitoneal injection of anti-CTLA-4 mAb abrogated the effect of syngeneic HSCT on prolonging islet allograft survival, inhibiting activity of T cells in response to alloantigen, promoting Th1 to Th2 immune deviation and up regulating CD4(+)CD25(+)Foxp3(+) Tregs. Syngeneic HSCT plus preconditioning of sublethal irradiation induces tolerance and improves islet allograft survival in fully mismatched mice model. Th1 to Th2 immune deviation, increased CD4(+)CD25(+)Foxp3(+) Tregs and up-regulation of CTLA-4 maybe contribute to the tolerogenic effect induced by syngeneic HSCT. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Long-term inhibition of dipeptidyl peptidase IV improves glucose tolerance and preserves islet function in mice

    DEFF Research Database (Denmark)

    Reimer, M Kvist; Holst, Jens Juul; Ahrén, B

    2002-01-01

    DPPIV activity to 0.01+/-0.03 mU/ml vs 3.26+/-0.19 mU/ml in controls (PGlucose tolerance after gastric glucose gavage, as judged by the area under the curve for plasma glucose levels over the 120 min study period, was increased after 8 weeks by NVP DPP728 in mice fed normal diet (P=0.......029) and in mice fed a high-fat diet (P=0.036). This was accompanied by increased plasma levels of insulin and intact GLP-1. Glucose-stimulated insulin secretion from islets isolated from NVP DPP728-treated animals after 8 weeks of treatment was increased as compared with islets from control animals at 5.6, 8...... and such mice rendered glucose-intolerant and insulin-resistant by feeding a high-fat diet. DESIGN: In mice fed a standard diet (11% fat) or a high-fat diet (58% fat), NVP DPP728 (0.12 micromol/g body weight) was administered in the drinking water for an 8 week period. RESULTS: DPPIV inhibition reduced plasma...

  8. Mesenchymal stem cell and derived exosome as small RNA carrier and Immunomodulator to improve islet transplantation.

    Science.gov (United States)

    Wen, Di; Peng, Yang; Liu, Di; Weizmann, Yossi; Mahato, Ram I

    2016-09-28

    Human bone marrow mesenchymal stem cells (hBMSCs) and their exosomes can suppress immune reaction and deliver small RNAs. Thus, they may improve islet transplantation by delivering small RNAs for promoting islet function and inhibiting immune rejection. Here, we proposed an hBMSC and its exosome-based therapy to overcome immune rejection and poor islet function, both of which hinder the success of islet transplantation. We found overexpressed siFas and anti-miR-375 in plasmid encoding shFas and anti-miR-375 transfected hBMSC-derived exosomes, which silenced Fas and miR-375 of human islets and improved their viability and function against inflammatory cytokines. This plasmid transfected hBMSCs downregulated Fas and miR-375 of human islets in a humanized NOD scid gamma (NSG) mouse model, whose immune reaction was inhibited by injecting hBMSC and peripheral blood mononuclear cell (PBMC) co-cultured exosomes. These exosomes suppressed immune reaction by inhibiting PBMC proliferation and enhancing regulatory T cell (Treg) function. Collectively, our studies elucidated the mechanisms of RNA delivery from hBMSCs to human islets and the immunosuppressive effect of hBMSC and peripheral blood mononuclear cell co-cultured exosomes for improving islet transplantation. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Quality of life improves for pediatric patients after total pancreatectomy and islet autotransplant for chronic pancreatitis.

    Science.gov (United States)

    Bellin, Melena D; Freeman, Martin L; Schwarzenberg, Sarah Jane; Dunn, Ty B; Beilman, Gregory J; Vickers, Selwyn M; Chinnakotla, Srinath; Balamurugan, A N; Hering, Bernhard J; Radosevich, David M; Moran, Antoinette; Sutherland, David E R

    2011-09-01

    Total pancreatectomy (TP) and islet autotransplant (IAT) have been used to treat patients with painful chronic pancreatitis. Initial studies indicated that most patients experienced significant pain relief, but there were few validated measures of quality of life. We investigated whether health-related quality of life improved among pediatric patients undergoing TP/IAT. Nineteen consecutive children (aged 5-18 years) undergoing TP/IAT from December 2006 to December 2009 at the University of Minnesota completed the Medical Outcomes Study 36-item Short Form (SF-36) health questionnaire before and after surgery. Insulin requirements were recorded. Before TP/IAT, patients had below average health-related quality of life, based on data from the Medical Outcomes Study SF-36; they had a mean physical component summary (PCS) score of 30 and mental component summary (MCS) score of 34 (2 and 1.5 standard deviations, respectively, below the mean for the US population). By 1 year after surgery, PCS and MCS scores improved to 50 and 46, respectively (global effect, PCS P Puestow) had lower yields of islets (P = .01) and greater incidence of insulin dependence (P = .04). Quality of life (physical and emotional components) significantly improve after TP/IAT in subsets of pediatric patients with severe chronic pancreatitis. Minimal or no insulin was required for most patients, although islet yield was reduced in patients with previous surgical drainage operations. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

  10. Human adipose tissue-derived mesenchymal stem cells differentiate into insulin, somatostatin, and glucagon expressing cells

    International Nuclear Information System (INIS)

    Timper, Katharina; Seboek, Dalma; Eberhardt, Michael; Linscheid, Philippe; Christ-Crain, Mirjam; Keller, Ulrich; Mueller, Beat; Zulewski, Henryk

    2006-01-01

    Mesenchymal stem cells (MSC) from mouse bone marrow were shown to adopt a pancreatic endocrine phenotype in vitro and to reverse diabetes in an animal model. MSC from human bone marrow and adipose tissue represent very similar cell populations with comparable phenotypes. Adipose tissue is abundant and easily accessible and could thus also harbor cells with the potential to differentiate in insulin producing cells. We isolated human adipose tissue-derived MSC from four healthy donors. During the proliferation period, the cells expressed the stem cell markers nestin, ABCG2, SCF, Thy-1 as well as the pancreatic endocrine transcription factor Isl-1. The cells were induced to differentiate into a pancreatic endocrine phenotype by defined culture conditions within 3 days. Using quantitative PCR a down-regulation of ABCG2 and up-regulation of pancreatic developmental transcription factors Isl-1, Ipf-1, and Ngn3 were observed together with induction of the islet hormones insulin, glucagon, and somatostatin

  11. INSULIN-SECRETION BY RAT ISLET ISOGRAFTS OF A DEFINED ENDOCRINE VOLUME AFTER TRANSPLANTATION TO 3 DIFFERENT SITES

    NARCIS (Netherlands)

    VANSUYLICHEM, PTR; STRUBBE, JH; HOUWING, H; WOLTERS, GHJ; VANSCHILFGAARDE, R

    1992-01-01

    We have analysed the graft function of rat islet isografts of identical and well-defined endocrine volumes after transplantation to three different sites (kidney, liver and spleen). Graft endocrine mass was determined by measuring the total islet volume prior to transplantation and was chosen to be

  12. Insulin secretion by rat islet isografts of a defined endocrine volume after transplantation to three different sites

    NARCIS (Netherlands)

    Suylichem, P.T.R. van; Strubbe, J.H.; Houwing, H.; Wolters, G.H.J.; Schilfgaarde, R. van

    1992-01-01

    We have analysed the graft function of rat islet isografts of identical and well-defined endocrine volumes after transplantation to three different sites (kidney, liver and spleen). Graft endocrine mass was determined by measuring the total islet volume prior to transplantation and was chosen to be

  13. Silicon nanopore membrane (SNM) for islet encapsulation and immunoisolation under convective transport

    Science.gov (United States)

    Song, Shang; Faleo, Gaetano; Yeung, Raymond; Kant, Rishi; Posselt, Andrew M.; Desai, Tejal A.; Tang, Qizhi; Roy, Shuvo

    2016-03-01

    Problems associated with islet transplantation for Type 1 Diabetes (T1D) such as shortage of donor cells, use of immunosuppressive drugs remain as major challenges. Immune isolation using encapsulation may circumvent the use of immunosuppressants and prolong the longevity of transplanted islets. The encapsulating membrane must block the passage of host’s immune components while providing sufficient exchange of glucose, insulin and other small molecules. We report the development and characterization of a new generation of semipermeable ultrafiltration membrane, the silicon nanopore membrane (SNM), designed with approximately 7 nm-wide slit-pores to provide middle molecule selectivity by limiting passage of pro-inflammatory cytokines. Moreover, the use of convective transport with a pressure differential across the SNM overcomes the mass transfer limitations associated with diffusion through nanometer-scale pores. The SNM exhibited a hydraulic permeability of 130 ml/hr/m2/mmHg, which is more than 3 fold greater than existing polymer membranes. Analysis of sieving coefficients revealed 80% reduction in cytokines passage through SNM under convective transport. SNM protected encapsulated islets from infiltrating cytokines and retained islet viability over 6 hours and remained responsive to changes in glucose levels unlike non-encapsulated controls. Together, these data demonstrate the novel membrane exhibiting unprecedented hydraulic permeability and immune-protection for islet transplantation therapy.

  14. Method of insulin determination by radioimmunoassay technique

    Energy Technology Data Exchange (ETDEWEB)

    Kokot, F; Kuska, J [Slaska Akademia Medyczna, Katowice (Poland)

    1973-01-01

    Technical details of a radioimmunological method of insulin determination in blood serum have been presented. Clinical value of the method was checked in 31 healthy subjects following oral or intravenous glucose administration, or after pancreatic islet stimulation using tolbutamide.

  15. Dysregulation of Dicer1 in Beta Cells Impairs Islet Architecture and Glucose Metabolism

    Directory of Open Access Journals (Sweden)

    Amitai D. Mandelbaum

    2012-01-01

    Full Text Available microRNAs (miRNAs play important roles in pancreas development and in regulation of insulin expression in the adult. Here we show that loss of miRNAs activity in beta-cells during embryonic development results in lower beta-cell mass and in impaired glucose tolerance. Dicer1-null cells initially constitute a significant portion of the total beta-cell population. However, during postnatal development, Dicer1-null cells are depleted. Furthermore, wild-type beta cells are repopulating the islets in complex compensatory dynamics. Because loss of Dicer1 is also associated with changes in the distribution of membranous E-cadherin, we hypothesized that E-cadherin activity may play a role in beta cell survival or islet architecture. However, genetic loss of E-cadherin function does not impair islet architecture, suggesting that miRNAs likely function through other or redundant effectors in the endocrine pancreas.

  16. Continuous Quadrupole Magnetic Separation of Islets during Digestion Improves Purified Porcine Islet Viability.

    Science.gov (United States)

    Weegman, Bradley P; Kumar Sajja, Venkata Sunil; Suszynski, Thomas M; Rizzari, Michael D; Scott Iii, William E; Kitzmann, Jennifer P; Mueller, Kate R; Hanley, Thomas R; Kennedy, David J; Todd, Paul W; Balamurugan, Appakalai N; Hering, Bernhard J; Papas, Klearchos K

    2016-01-01

    Islet transplantation (ITx) is an emerging and promising therapy for patients with uncontrolled type 1 diabetes. The islet isolation and purification processes require exposure to extended cold ischemia, warm-enzymatic digestion, mechanical agitation, and use of damaging chemicals for density gradient separation (DG), all of which reduce viable islet yield. In this paper, we describe initial proof-of-concept studies exploring quadrupole magnetic separation (QMS) of islets as an alternative to DG to reduce exposure to these harsh conditions. Three porcine pancreata were split into two parts, the splenic lobe (SPL) and the combined connecting/duodenal lobes (CDL), for paired digestions and purifications. Islets in the SPL were preferentially labeled using magnetic microparticles (MMPs) that lodge within the islet microvasculature when infused into the pancreas and were continuously separated from the exocrine tissue by QMS during the collection phase of the digestion process. Unlabeled islets from the CDL were purified by conventional DG. Islets purified by QMS exhibited significantly improved viability (measured by oxygen consumption rate per DNA, p < 0.03) and better morphology relative to control islets. Islet purification by QMS can reduce the detrimental effects of prolonged exposure to toxic enzymes and density gradient solutions and substantially improve islet viability after isolation.

  17. Continuous Quadrupole Magnetic Separation of Islets during Digestion Improves Purified Porcine Islet Viability

    Directory of Open Access Journals (Sweden)

    Bradley P. Weegman

    2016-01-01

    Full Text Available Islet transplantation (ITx is an emerging and promising therapy for patients with uncontrolled type 1 diabetes. The islet isolation and purification processes require exposure to extended cold ischemia, warm-enzymatic digestion, mechanical agitation, and use of damaging chemicals for density gradient separation (DG, all of which reduce viable islet yield. In this paper, we describe initial proof-of-concept studies exploring quadrupole magnetic separation (QMS of islets as an alternative to DG to reduce exposure to these harsh conditions. Three porcine pancreata were split into two parts, the splenic lobe (SPL and the combined connecting/duodenal lobes (CDL, for paired digestions and purifications. Islets in the SPL were preferentially labeled using magnetic microparticles (MMPs that lodge within the islet microvasculature when infused into the pancreas and were continuously separated from the exocrine tissue by QMS during the collection phase of the digestion process. Unlabeled islets from the CDL were purified by conventional DG. Islets purified by QMS exhibited significantly improved viability (measured by oxygen consumption rate per DNA, p<0.03 and better morphology relative to control islets. Islet purification by QMS can reduce the detrimental effects of prolonged exposure to toxic enzymes and density gradient solutions and substantially improve islet viability after isolation.

  18. CaMKII regulates contraction- but not insulin-induced glucose uptake in mouse skeletal muscle.

    Science.gov (United States)

    Witczak, Carol A; Jessen, Niels; Warro, Daniel M; Toyoda, Taro; Fujii, Nobuharu; Anderson, Mark E; Hirshman, Michael F; Goodyear, Laurie J

    2010-06-01

    Studies using chemical inhibitors have suggested that the Ca(2+)-sensitive serine/threonine kinase Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a key regulator of both insulin- and contraction-stimulated glucose uptake in skeletal muscle. However, due to nonspecificity of these inhibitors, the specific role that CaMKII may play in the regulation of glucose uptake is not known. We sought to determine whether specific inhibition of CaMKII impairs insulin- and/or contraction-induced glucose uptake in mouse skeletal muscle. Expression vectors containing green fluorescent protein conjugated to a CaMKII inhibitory (KKALHRQEAVDCL) or control (KKALHAQERVDCL) peptide were transfected into tibialis anterior muscles by in vivo electroporation. After 1 wk, muscles were assessed for peptide expression, CaMK activity, insulin- and contraction-induced 2-[(3)H]deoxyglucose uptake, glycogen concentrations, and changes in intracellular signaling proteins. Expression of the CaMKII inhibitory peptide decreased muscle CaMK activity approximately 35% compared with control peptide. Insulin-induced glucose uptake was not changed in muscles expressing the inhibitory peptide. In contrast, expression of the inhibitory peptide significantly decreased contraction-induced muscle glucose uptake (approximately 30%). Contraction-induced decreases in muscle glycogen were not altered by the inhibitory peptide. The CaMKII inhibitory peptide did not alter expression of the glucose transporter GLUT4 and did not impair contraction-induced increases in the phosphorylation of AMP-activated protein kinase (Thr(172)) or TBC1D1/TBC1D4 on phospho-Akt substrate sites. These results demonstrate that CaMKII does not regulate insulin-stimulated glucose uptake in skeletal muscle. However, CaMKII plays a critical role in the regulation of contraction-induced glucose uptake in mouse skeletal muscle.

  19. DHEA supplementation in ovariectomized rats reduces impaired glucose-stimulated insulin secretion induced by a high-fat diet

    Directory of Open Access Journals (Sweden)

    Katherine Veras

    2014-01-01

    Full Text Available Dehydroepiandrosterone (DHEA and the dehydroepiandrosterone sulfate (DHEA-S are steroids produced mainly by the adrenal cortex. There is evidence from both human and animal models suggesting beneficial effects of these steroids for obesity, diabetes mellitus, hypertension, and osteoporosis, conditions associated with the post-menopausal period. Accordingly, we hypothesized that DHEA supplementation in ovariectomized (OVX female rats fed a high-fat diet would maintain glucose-induced insulin secretion (GSIS and pancreatic islet function. OVX resulted in a 30% enlargement of the pancreatic islets area compared to the control rats, which was accompanied by a 50% reduction in the phosphorylation of AKT protein in the pancreatic islets. However, a short-term high-fat diet induced insulin resistance, accompanied by impaired GSIS in isolated pancreatic islets. These effects were reversed by DHEA treatment, with improved insulin sensitivity to levels similar to the control group, and with increased serine phosphorylation of the AKT protein. These data confirm the protective effect of DHEA on the endocrine pancreas in a situation of diet-induced overweight and low estrogen concentrations, a phenotype similar to that of the post-menopausal period.

  20. High plasma levels of islet amyloid polypeptide in young with new-onset of type 1 diabetes mellitus.

    Directory of Open Access Journals (Sweden)

    Johan F Paulsson

    Full Text Available AIMS/HYPOTHESIS: Islet amyloid polypeptide (IAPP is a beta cell hormone secreted together with insulin upon glucose stimulation. IAPP participates in normal glucose regulation, but IAPP is also known for its ability to misfold and form islet amyloid. Amyloid fibrils form through smaller cell toxic intermediates and deposited amyloid disrupts normal islet architecture. Even though IAPP and amyloid formation are much discussed in type 2 diabetes, our aim was to study the significance of IAPP in type 1 diabetes. RESULTS: Plasma IAPP levels in children and adolescents with newly diagnosed type 1 diabetes (n = 224 were analysed and concentrations exceeding 100 pmol/L (127.2-888.7 pmol/L were found in 11% (25/224. The IAPP increase did not correlate with C-peptide levels. CONCLUSIONS/INTERPRETATION: Plasma levels of IAPP and insulin deviate in a subpopulation of young with newly-diagnosed type 1 diabetes. The determined elevated levels of IAPP might increase the risk for IAPP misfolding and formation of cell toxic amyloid in beta cells. This finding add IAPP-aggregation to the list over putative pathological factors causing type 1 diabetes.

  1. Islet Transplantation in Type 1 Diabetes: Ongoing Challenges, Refined Procedures, and Long-Term Outcome

    Science.gov (United States)

    Shapiro, A.M. James

    2012-01-01

    Remarkable progress has been made in islet transplantation over a span of 40 years. Once just an experimental curiosity in mice, this therapy has moved forward, and can now provide robust therapy for highly selected patients with type 1 diabetes (T1D), refractory to stabilization by other means. This progress could not have occurred without extensive dynamic international collaboration. Currently, 1,085 patients have undergone islet transplantation at 40 international sites since the Edmonton Protocol was reported in 2000 (752 allografts, 333 autografts), according to the Collaborative Islet Transplant Registry. The long-term results of islet transplantation in selected centers now match registry data of pancreas-alone transplantation, with 6 sites reporting five-year insulin independence rates ≥50%. Islet transplantation has been criticized for the use of multiple donor pancreas organs, but progress has also occurred in single-donor success, with 10 sites reporting increased single-donor engraftment. The next wave of innovative clinical trial interventions will address instant blood-mediated inflammatory reaction (IBMIR), apoptosis, and inflammation, and will translate into further marked improvements in single-donor success. Effective control of auto- and alloimmunity is the key to long-term islet function, and high-resolution cellular and antibody-based assays will add considerable precision to this process. Advances in immunosuppression, with new antibody-based targeting of costimulatory blockade and other T-B cellular signaling, will have further profound impact on the safety record of immunotherapy. Clinical trials will move forward shortly to test out new human stem cell derived islets, and in parallel trials will move forward, testing pig islets for compatibility in patients. Induction of immunological tolerance to self-islet antigens and to allografts is a difficult challenge, but potentially within our grasp. PMID:23804275

  2. Hair Follicle Dermal Sheath Derived Cells Improve Islet Allograft Survival without Systemic Immunosuppression

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2015-01-01

    Full Text Available Immunosuppressive drugs successfully prevent rejection of islet allografts in the treatment of type I diabetes. However, the drugs also suppress systemic immunity increasing the risk of opportunistic infection and cancer development in allograft recipients. In this study, we investigated a new treatment for autoimmune diabetes using naturally immune privileged, hair follicle derived, autologous cells to provide localized immune protection of islet allotransplants. Islets from Balb/c mouse donors were cotransplanted with syngeneic hair follicle dermal sheath cup cells (DSCC, group 1 or fibroblasts (FB, group 2 under the kidney capsule of immune-competent, streptozotocin induced, diabetic C57BL/6 recipients. Group 1 allografts survived significantly longer than group 2 (32.2 ± 12.2 versus 14.1 ± 3.3 days, P<0.001 without administration of any systemic immunosuppressive agents. DSCC reduced T cell activation in the renal lymph node, prevented graft infiltrates, modulated inflammatory chemokine and cytokine profiles, and preserved better beta cell function in the islet allografts, but no systemic immunosuppression was observed. In summary, DSCC prolong islet allograft survival without systemic immunosuppression by local modulation of alloimmune responses, enhancing of beta cell survival, and promoting of graft revascularization. This novel finding demonstrates the capacity of easily accessible hair follicle cells to be used as local immunosuppression agents in islet transplantation.

  3. Maternal Moderate Physical Training during Pregnancy Attenuates the Effects of a Low-Protein Diet on the Impaired Secretion of Insulin in Rats: Potential Role for Compensation of Insulin Resistance and Preventing Gestational Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Carol Góis Leandro

    2012-01-01

    Full Text Available The effects of pregestational and gestational low-to-moderate physical training on insulin secretion in undernourished mothers were evaluated. Virgin female Wistar rats were divided into four groups as follows: control (C, n=5; trained (T, n=5; low-protein diet (LP, n=5; trained with a low-protein diet (T + LP, n=5. Trained rats ran on a treadmill over a period of 4 weeks before mate (5 days week−1 and 60 min day−1, at 65% of VO2max. At pregnancy, the intensity and duration of the exercise were reduced. Low-protein groups were provided with an 8% casein diet, and controls were provided with a 17% casein diet. At third day after delivery, mothers and pups were killed and islets were isolated by collagenase digestion of pancreas and incubated for a further 1 h with medium containing 5.6 or 16.7 mM glucose. T mothers showed increased insulin secretion by isolated islets incubated with 16.7 mM glucose, whereas LP group showed reduced secretion of insulin by isolated islets when compared with both C and LP + T groups. Physical training before and during pregnancy attenuated the effects of a low-protein diet on the secretion of insulin, suggesting a potential role for compensation of insulin resistance and preventing gestational diabetes mellitus.

  4. Characterization of a pancreatic islet cell tumor in a polar bear (Ursus maritimus).

    Science.gov (United States)

    Fortin, Jessica S; Benoit-Biancamano, Marie-Odile

    2014-01-01

    Herein, we report a 25-year-old male polar bear suffering from a pancreatic islet cell tumor. The aim of this report is to present a case of this rare tumor in a captive polar bear. The implication of potential risk factors such as high carbohydrate diet or the presence of amyloid fibril deposits was assessed. Necropsy examination revealed several other changes, including nodules observed in the liver, spleen, pancreas, intestine, and thyroid glands that were submitted for histopathologic analysis. Interestingly, the multiple neoplastic nodules were unrelated and included a pancreatic islet cell tumor. Immunohistochemistry of the pancreas confirmed the presence of insulin and islet amyloid polypeptide (IAPP) within the pancreatic islet cells. The IAPP gene was extracted from the paraffin-embedded liver tissue and sequenced. IAPP cDNA from the polar bear exhibits some differences as compared to the sequence published for several other species. Different factors responsible for neoplasms in bears such as diet, infectious agents, and industrial chemical exposure are reviewed. This case report raised several issues that further studies may address by evaluating the prevalence of cancers in captive or wild animals. © 2014 Wiley Periodicals, Inc.

  5. Comparison of the Ovary and Kidney as Sites for Islet Transplantation in Diabetic Rats.

    Science.gov (United States)

    Karakose, M; Pinarli, F A; Arslan, M S; Boyuk, G; Boztok, B; Albayrak, A; Ulus, A T; Cakal, E; Delibasi, T

    2016-01-01

    Currently, the most commonly used site for clinical islet transplantation is the liver although it is far from being an ideal site. Low oxygen tension and the induction of an inflammatory response impair islet implantation and lead to significant early loss of islet. The present study aimed to investigate and compare the efficacy of islet transplantation to the ovary and kidney subcapsule in diabetic rats. The study was performed with 3 groups of rats (control, ovary, and kidney subcapsule) including 6 Sprague female rats each. Diabetes model was created with the use of streptozotocin, and blood glucose levels of the rats were measured after 72 hours. Thirty days after the transplantation, blood samples were obtained from the rats, and then pancreas, kidney, and ovary specimens were fixed in 10% formaldehyde and the experiment completed. After staining with hematoxylin and eosin, the tissue samples were morphologically evaluated by a specialist histopathologist. Changes in mean blood glucose and C-peptide levels were statistically significant in the ovary and kidney subcapsule groups. Histologic examination revealed that granulosus insulin-bearing cells were detected in the islet grafts of both ovary and kidney subcapsule groups. The renal subcapsule group had inflammation signs on histologic examination. The islet cells of both ovary and renal subcapsule groups had no vacuolization. We showed that the ovary might be a new site for islet transplantation. Further research should be done on whether the initial results of this study can be reproduced in larger numbers of animal models and eventually in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Facilitated Engraftment of Isolated Islets Coated With Expanded Vascular Endothelial Cells for Islet Transplantation.

    Science.gov (United States)

    Barba-Gutierrez, D Alonso; Daneri-Navarro, A; Villagomez-Mendez, J Jesus Alejandro; Kanamune, J; Robles-Murillo, A Karina; Sanchez-Enriquez, S; Villafan-Bernal, J Rafael; Rivas-Carrillo, J D

    2016-03-01

    Diabetes is complex disease, which involves primary metabolic changes followed by immunological and vascular pathophysiological adjustments. However, it is mostly characterized by an unbalanced decreased number of the β-cells unable to maintain the metabolic requirements and failure to further regenerate newly functional pancreatic islets. The objective of this study was to analyze the properties of the endothelial cells to facilitate the islet cells engraftment after islet transplantation. We devised a co-cultured engineer system to coat isolated islets with vascular endothelial cells. To assess the cell integration of cell-engineered islets, we stained them for endothelial marker CD31 and nuclei counterstained with DAPI dye. We comparatively performed islet transplantations into streptozotocin-induced diabetic mice and recovered the islet grafts for morphometric analyses on days 3, 7, 10, and 30. Blood glucose levels were measured continuously after islet transplantation to monitor the functional engraftment and capacity to achieve metabolic control. Cell-engineered islets showed a well-defined rounded shape after co-culture when compared with native isolated islets. Furthermore, the number of CD31-positive cells layered on the islet surface showed a direct proportion with engraftment capacities and less TUNEL-positive cells on days 3 and 7 after transplantation. We observed that vascular endothelial cells could be functional integrated into isolated islets. We also found that islets that are coated with vascular endothelial cells increased their capacity to engraft. These findings indicate that islets coated with endothelial cells have a greater capacity of engraftment and thus establish a definitely vascular network to support the metabolic requirements. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Effect of oxygen supply on the size of implantable islet-containing encapsulation devices.

    Science.gov (United States)

    Papas, Klearchos K; Avgoustiniatos, Efstathios S; Suszynski, Thomas M

    2016-03-01

    Beta-cell replacement therapy is a promising approach for the treatment of diabetes but is currently limited by the human islet availability and by the need for systemic immunosuppression. Tissue engineering approaches that will enable the utilization of islets or β-cells from alternative sources (such as porcine islets or human stem cell derived beta cells) and minimize or eliminate the need for immunosuppression have the potential to address these critical limitations. However, tissue engineering approaches are critically hindered by the device size (similar to the size of a large flat screen television) required for efficacy in humans. The primary factor dictating the device size is the oxygen availability to islets to support their viability and function (glucose-stimulated insulin secretion [GSIS]). GSIS is affected (inhibited) at a much higher oxygen partial pressure [pO2] than that of viability (e.g. 10 mmHg as opposed to 0.1 mmHg). Enhanced oxygen supply (higher pO2) than what is available in vivo at transplant sites can have a profound effect on the required device size (potentially reduce it to the size of a postage stamp). This paper summarizes key information on the effect of oxygen on islet viability and function within immunoisolation devices and describes the potential impact of enhanced oxygen supply to devices in vivo on device size reduction.

  8. Potent Insulin Secretagogue from Scoparia dulcis Linn of Nepalese Origin.

    Science.gov (United States)

    Sharma, Khaga Raj; Adhikari, Achyut; Hafizur, Rahman M; Hameed, Abdul; Raza, Sayed Ali; Kalauni, Surya Kant; Miyazaki, Jun-Ichi; Choudhary, M Iqbal

    2015-10-01

    Ethno-botanical inspired isolation from plant Scoparia dulcis Linn. (Sweet Broomweed) yielded six compounds, coixol (1), glutinol (2), glutinone (3), friedelin (4), betulinic acid (5), and tetratriacontan-1-ol (6). There structures were identified using mass and 1D- and 2D-NMR spectroscopy techniques. Compounds 1-6 were evaluated for their insulin secretory activity on isolated mice islets and MIN-6 pancreatic β-cell line, and compounds 1 and 2 were found to be potent and mildly active, respectively. Compound 1 was further evaluated for insulin secretory activity on MIN-6 cells. Compound 1 was subjected to in vitro cytotoxicity assay against MIN-6, 3T3 cell lines, and islet cells, and in vivo acute toxicity test in mice that was found to be non-toxic. The insulin secretory activity of compounds 1 and 2 supported the ethno-botanic uses of S. dulcis as an anti-diabetic agent. Copyright © 2015 John Wiley & Sons, Ltd.

  9. Proghrelin peptides: Desacyl ghrelin is a powerful inhibitor of acylated ghrelin, likely to impair physiological effects of acyl ghrelin but not of obestatin A study of pancreatic polypeptide secretion from mouse islets

    DEFF Research Database (Denmark)

    Kumar, Rajesh; Salehi, Albert; Rehfeld, Jens F

    2010-01-01

    Proghrelin, produced by the ghrelin (A-like) cells of the gastric mucosa, gives rise to cleavage products, including desacyl ghrelin, acyl ghrelin and obestatin. The products are thought to be secreted concomitantly. In an earlier study we found acyl ghrelin and obestatin, but not desacyl ghrelin......, to suppress the release of hormones from isolated islets of mouse and rat pancreas....

  10. Protective efficacy of folic acid and vitamin B12 against nicotine-induced toxicity in pancreatic islets of the rat

    Directory of Open Access Journals (Sweden)

    Bhattacharjee Ankita

    2015-06-01

    Full Text Available Although cigarette smoking is associated with insulin resistance and an increased risk for type 2 diabetes, few studies have examined the effect of nicotine on the adult endocrine pancreas. In this study, male Wister rats were treated with nicotine (3 mg/kg body weight/day with or without supplementation of folic acid (36 μg/kg body weight/day or vitamin B12 (0.63 μg/kg body weight/day alone or in combination. Fasting blood glucose, insulin and HBA1C level and different oxidative and anti-oxidative stress parameters were measured and pancreatic tissue sections were stained with eosin-haematoxylene. Data were analysed by nonparametric statistics. The results revealed that nicotine induced prediabetes condition with subsequent damage to pancreatic islets in rats. Nicotine also caused oxidative stress in pancreatic tissue as evidenced by increased nitric oxide and malondialdehyde level and decreased superoxide dismutase, catalase and reduced glutathione level. Compared to vitamin B12 supplementation, folic acid blunted the nicotine-induced toxicity in pancreatic islets with higher efficacy. Further, folic acid and vitamin B12 in combination were able to confer significant protection on pancreatic islets against nicotine induced toxicity. These results suggest that supplementation of folic acid and vitamin B12 in combination may be a possible strategy of detoxification against nicotine-induced toxicity in pancreatic islets of the rat.

  11. Cannabinoid 2 Receptor Agonist Improves Systemic Sensitivity to Insulin in High-Fat Diet/Streptozotocin-Induced Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Xiuyuan Zhang

    2016-12-01

    Full Text Available Background/Aims: The endocannabinoid signalling (ECS system has been known to regulate glucose homeostasis. Previous studies have suggested that the cannabinoid 2 (CB2 receptor may play a regulatory role on insulin secretion, immune modulation and insulin resistance. Given that diabetes and insulin resistance are attributable to elevated inflammatory tone, we investigated the role of CB2 receptor on glucose tolerance and insulin sensitivity in high-fat diet (HFD/streptozotocin (STZ-induced mice. Methods: Diabetes was induced in male ICR mice by HFD/STZ and exposed to a CB2 receptor agonist, SER601, for 2- or 4-weeks via subcutaneous implantation of osmotic minipumps. Glucose and insulin tolerance tests were performed at the end of treatment. Islets were isolated for assessment of β-cell function. Pancreases and skeletal muscles were also obtained for histological analyses. Results: Despite a lack of impact on glucose tolerance, substantial improvement on insulin sensitivity was observed in SER601-treated mice, which could partly be attributed to improved islet β-cell function, shown as increased glucose-induced insulin secretion and insulin content. No changes on islet macrophage infiltration or skeletal muscle fat deposition were detectable from SER601-treated mice. However, a major decrease in body weight was recorded at the end of 4-week SER601 exposure, accompanied by a lack of epididymal adipose mass in SER601-treated mice. Conclusion: Our data suggest a lipolytic role of SER601 in HFD/STZ-induced diabetic mice, which results in significant improvement of systemic insulin sensitivity. Thus, the CB2 receptor may be considered a promising target for therapeutic development against insulin resistance and obesity-related diabetes.

  12. Induction of insulin and islet amyloid polypeptide production in pancreatic islet glucagonoma cells by insulin promoter factor 1

    DEFF Research Database (Denmark)

    Serup, P; Jensen, J; Andersen, F G

    1996-01-01

    Insulin promoter factor 1 (IPF1), a member of the homeodomain protein family, serves an early role in pancreas formation, as evidenced by the lack of pancreas formation in mice carrying a targeted disruption of the IPF1 gene [Jonsson, J., Carlsson, L., Edlund, T. & Edlund, H. (1994) Nature (London...

  13. Chronic antidiabetic sulfonylureas in vivo: reversible effects on mouse pancreatic beta-cells.

    Directory of Open Access Journals (Sweden)

    Maria Sara Remedi

    2008-10-01

    Full Text Available Pancreatic beta-cell ATP-sensitive potassium (K ATP channels are critical links between nutrient metabolism and insulin secretion. In humans, reduced or absent beta-cell K ATP channel activity resulting from loss-of-function K ATP mutations induces insulin hypersecretion. Mice with reduced K ATP channel activity also demonstrate hyperinsulinism, but mice with complete loss of K ATP channels (K ATP knockout mice show an unexpected insulin undersecretory phenotype. Therefore we have proposed an "inverse U" hypothesis to explain the response to enhanced excitability, in which excessive hyperexcitability drives beta-cells to insulin secretory failure without cell death. Many patients with type 2 diabetes treated with antidiabetic sulfonylureas (which inhibit K ATP activity and thereby enhance insulin secretion show long-term insulin secretory failure, which we further suggest might reflect a similar progression.To test the above hypotheses, and to mechanistically investigate the consequences of prolonged hyperexcitability in vivo, we used a novel approach of implanting mice with slow-release sulfonylurea (glibenclamide pellets, to chronically inhibit beta-cell K ATP channels. Glibenclamide-implanted wild-type mice became progressively and consistently diabetic, with significantly (p < 0.05 reduced insulin secretion in response to glucose. After 1 wk of treatment, these mice were as glucose intolerant as adult K ATP knockout mice, and reduction of secretory capacity in freshly isolated islets from implanted animals was as significant (p < 0.05 as those from K ATP knockout animals. However, secretory capacity was fully restored in islets from sulfonylurea-treated mice within hours of drug washout and in vivo within 1 mo after glibenclamide treatment was terminated. Pancreatic immunostaining showed normal islet size and alpha-/beta-cell distribution within the islet, and TUNEL staining showed no evidence of apoptosis.These results demonstrate that

  14. The insulinogenic effect of whey protein is partially mediated by a direct effect of amino acids and GIP on β-cells

    DEFF Research Database (Denmark)

    Salehi, Albert; Gunnerud, Ulrika; Muhammed, Sarheed J

    2012-01-01

    Whey protein increases postprandial serum insulin levels. This has been associated with increased serum levels of leucine, isoleucine, valine, lysine, threonine and the incretin hormone glucose-dependent insulinotropic polypeptide (GIP). We have examined the effects of these putative mediators...... of whey's action on insulin secretion from isolated mouse Langerhans islets....

  15. VEGF-conjugated alginate hydrogel prompt angiogenesis and improve pancreatic islet engraftment and function in type 1 diabetes

    International Nuclear Information System (INIS)

    Yin, Nina; Han, Yongming; Xu, Hanlin; Gao, Yisen; Yi, Tao; Yao, Jiale; Dong, Li; Cheng, Dejun; Chen, Zebin

    2016-01-01

    Type 1 diabetes was a life-long disease that affected numerous people around the world. Insulin therapy has its limitations that may involve hyperglycemia and heavy burden of patient by repeated dose. Islet transplantation emerged as a promising approach to reach periodical reverse of diabetes, however, transplanted islets suffer from foreign body reaction and lack of nutrition and oxygen supply, especially in the blood-vessel-shortage subcutaneous site which was preferred by patient and surgeon. In this study, we designed and synthesized a vascular endothelial growth factor (VEGF) conjugated alginate material to encapsulate the transplanted islets via 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) reaction, and successful conjugation was confirmed by Nuclear Magnetic Resonance H1 spectrum. The best VEGF concentration (100 ng/ml) was determined by the combined studies of the mechanical property and endothelial cell growth assay. In vivo study, conjugated VEGF on alginate exhibited sustained promoting angiogenesis property after subcutaneous transplantation by histology study and islets encapsulated in this material achieved long term therapeutic effect (up to 50 days) in the diabetic mice model. In conclusion, this study establishes a simple biomaterial strategy for islet transplantation to enhance islet survival and function, which could be a feasible therapeutic alternative for type 1 diabetes. - Highlights: • We synthesized VEGF-conjugated alginate material to encapsulate the transplanted islets. • The biomaterials improve islet engraftment and function due to angiogenesis. • The biomaterials could be a strong support for cell therapy with islet transplantation in type 1 diabetes.

  16. VEGF-conjugated alginate hydrogel prompt angiogenesis and improve pancreatic islet engraftment and function in type 1 diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Nina; Han, Yongming [Department of Anatomy, Basic Medical College, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Xu, Hanlin [Pharmacy Faculty, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Gao, Yisen; Yi, Tao [Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Yao, Jiale; Dong, Li; Cheng, Dejun [Basic Medical College, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Chen, Zebin, E-mail: chenzebin-hbtcm@outlook.com [Acupuncture and Moxibustion College, Hubei University of Chinese Medicine/Hubei Provincial Collaborative Innovation Center of Preventive Treatment by Acupuncture and Moxibustion, Wuhan, Hubei (China)

    2016-02-01

    Type 1 diabetes was a life-long disease that affected numerous people around the world. Insulin therapy has its limitations that may involve hyperglycemia and heavy burden of patient by repeated dose. Islet transplantation emerged as a promising approach to reach periodical reverse of diabetes, however, transplanted islets suffer from foreign body reaction and lack of nutrition and oxygen supply, especially in the blood-vessel-shortage subcutaneous site which was preferred by patient and surgeon. In this study, we designed and synthesized a vascular endothelial growth factor (VEGF) conjugated alginate material to encapsulate the transplanted islets via 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) reaction, and successful conjugation was confirmed by Nuclear Magnetic Resonance H1 spectrum. The best VEGF concentration (100 ng/ml) was determined by the combined studies of the mechanical property and endothelial cell growth assay. In vivo study, conjugated VEGF on alginate exhibited sustained promoting angiogenesis property after subcutaneous transplantation by histology study and islets encapsulated in this material achieved long term therapeutic effect (up to 50 days) in the diabetic mice model. In conclusion, this study establishes a simple biomaterial strategy for islet transplantation to enhance islet survival and function, which could be a feasible therapeutic alternative for type 1 diabetes. - Highlights: • We synthesized VEGF-conjugated alginate material to encapsulate the transplanted islets. • The biomaterials improve islet engraftment and function due to angiogenesis. • The biomaterials could be a strong support for cell therapy with islet transplantation in type 1 diabetes.

  17. Insulin secretion and sensitivity in space flight: diabetogenic effects

    Science.gov (United States)

    Tobin, Brian W.; Uchakin, Peter N.; Leeper-Woodford, Sandra K.

    2002-01-01

    Nearly three decades of space flight research have suggested that there are subclinical diabetogenic changes that occur in microgravity. Alterations in insulin secretion, insulin sensitivity, glucose tolerance, and metabolism of protein and amino acids support the hypothesis that insulin plays an essential role in the maintenance of muscle mass in extended-duration space flight. Experiments in flight and after flight and ground-based bedrest studies have associated microgravity and its experimental paradigms with manifestations similar to those of diabetes, physical inactivity, and aging. We propose that these manifestations are characterized best by an etiology that falls into the clinical category of "other" causes of diabetes, including, but not restricted to, genetic beta-cell defects, insulin action defects, diseases of the endocrine pancreas, endocrinopathies, drug or chemically induced diabetes, infections, immune-mediated metabolic alteration, and a host of genetic related diseases. We present data showing alterations in tumor necrosis factor-alpha production, insulin secretion, and amino acid metabolism in pancreatic islets of Langerhans cultured in a ground-based cell culture bioreactor that mimics some of the effects of microgravity. Taken together, space flight research, ground-based studies, and bioreactor studies of pancreatic islets of Langerhans support the hypothesis that the pancreas is unable to overcome peripheral insulin resistance and amino acid dysregulation during space flight. We propose that measures of insulin secretion and insulin action will be necessary to design effective countermeasures against muscle loss, and we advance the "disposition index" as an essential model to be used in the clinical management of space flight-induced muscle loss.

  18. Maternal microchimerism: increased in the insulin positive compartment of type 1 diabetes pancreas but not in infiltrating immune cells or replicating islet cells.

    Directory of Open Access Journals (Sweden)

    Jody Ye

    Full Text Available Maternal microchimeric cells (MMc transfer across the placenta during pregnancy. Increased levels of MMc have been observed in several autoimmune diseases including type 1 diabetes but their role is unknown. It has been suggested that MMc are 1 effector cells of the immune response, 2 targets of the autoimmune response or 3 play a role in tissue repair. The aim of this study was to define the cellular phenotype of MMc in control (n = 14 and type 1 diabetes pancreas (n = 8.Using sex chromosome-based fluorescence in-situ hybridization, MMc were identified in male pancreas and their phenotype determined by concomitant immunofluorescence.In normal pancreas, MMc positive for endocrine, exocrine, duct and acinar markers were identified suggesting that these cells are derived from maternal progenitors. Increased frequencies of MMc were observed in type 1 diabetes pancreas (p = 0.03 with particular enrichment in the insulin positive fraction (p = 0.01. MMc did not contribute to infiltrating immune cells or Ki67+ islet cell populations in type 1 diabetes.These studies provide support for the hypothesis that MMc in human pancreas are derived from pancreatic precursors. Increased frequencies of MMc beta cells may contribute to the initiation of autoimmunity or to tissue repair but do not infiltrate islets in type 1 diabetes.

  19. Mitochondrial Dysfunction Contributes to Impaired Insulin Secretion in INS-1 Cells with Dominant-negative Mutations of HNF-1α and in HNF-1α-deficient Islets*

    Science.gov (United States)

    Pongratz, Rebecca L.; Kibbey, Richard G.; Kirkpatrick, Clare L.; Zhao, Xiaojian; Pontoglio, Marco; Yaniv, Moshe; Wollheim, Claes B.; Shulman, Gerald I.; Cline, Gary W.

    2009-01-01

    Maturity Onset Diabetes of the Young-type 3 (MODY-3) has been linked to mutations in the transcription factor hepatic nuclear factor (HNF)-1α, resulting in deficiency in glucose-stimulated insulin secretion. In INS-1 cells overexpressing doxycycline-inducible HNF-1α dominant-negative (DN-) gene mutations, and islets from Hnf-1α knock-out mice, insulin secretion was impaired in response to glucose (15 mm) and other nutrient secretagogues. Decreased rates of insulin secretion in response to glutamine plus leucine and to methyl pyruvate, but not potassium depolarization, indicate defects specific to mitochondrial metabolism. To identify the biochemical mechanisms responsible for impaired insulin secretion, we used 31P NMR measured mitochondrial ATP synthesis (distinct from glycolytic ATP synthesis) together with oxygen consumption measurements to determine the efficiency of mitochondrial oxidative phosphorylation. Mitochondrial uncoupling was significantly higher in DN-HNF-1α cells, such that rates of ATP synthesis were decreased by approximately one-half in response to the secretagogues glucose, glutamine plus leucine, or pyruvate. In addition to closure of the ATP-sensitive K+ channels with mitochondrial ATP synthesis, mitochondrial production of second messengers through increased anaplerotic flux has been shown to be critical for coupling metabolism to insulin secretion. 13C-Isotopomer analysis and tandem mass spectrometry measurement of Krebs cycle intermediates revealed a negative impact of DN-HNF-1α and Hnf-1α knock-out on mitochondrial second messenger production with glucose but not amino acids. Taken together, these results indicate that, in addition to reduced glycolytic flux, uncoupling of mitochondrial oxidative phosphorylation contributes to impaired nutrient-stimulated insulin secretion with either mutations or loss of HNF-1α. PMID:19376774

  20. Atorvastatin inhibits insulin synthesis by inhibiting the Ras/Raf/ERK/CREB pathway in INS-1 cells

    Science.gov (United States)

    Sun, Hongxi; Li, Yu; Sun, Bei; Hou, Ningning; Yang, Juhong; Zheng, Miaoyan; Xu, Jie; Wang, Jingyu; Zhang, Yi; Zeng, Xianwei; Shan, Chunyan; Chang, Bai; Chen, Liming; Chang, Baocheng

    2016-01-01

    Abstract Backround: Type 2 diabetes has become a global epidemic disease. Atorvastatin has become a cornerstone in the prevention and treatment of atherosclerosis. However, increasing evidence showed that statins can dose-dependently increase the risk of diabetes mellitus. The mechanism is not clear. Objective: The Ras complex pathway (Ras/Raf/extracellular signal-regulated kinase [ERK]/cAMP response element-binding protein [CREB]) is the major pathway that regulates the gene transcription. Except for the inhibition of cholesterol synthesis by inhibiting the 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-COA) reductase, statins can also downregulate the phosphorylation of a series of downstream substrates including the key proteins of the Ras complex pathway, therefore may inhibit the insulin syntheses in pancreatic beta cells. In our study, we investigated the inhibitory effect and the underlying mechanism of atorvastatin on insulin synthesis in rat islets. Methods: Islets were isolated from Wistar rats and cultured in Roswell Park Memorial Institute (RPMI)-1640 medium. The insulin content in the medium was measured by radioimmunoassay before and after the treatment of 50 μM atorvastatin. Effect of atorvastatin on the expression of insulin message Ribonucleic acid (mRNA) in pancreatic islet beta cells was also detected using quantitative real-time polymerase chain reaction. Western blotting was used to explore the possible role of the Ras complex pathway (Ras/Raf/ERK/CREB) in atorvastatin-inhibited insulin synthesis. The effects of atorvastatin on the binding of nuclear transcription factor p-CREB with CRE in INS-1 cells were examined via chromatin immunoprecipitation assay. Results: Compared with the control group, the insulin level decreased by 27.1% at 24 hours after atorvastatin treatment. Atorvastatin inhibited insulin synthesis by decreasing insulin mRNA expression of pancreatic islet beta cells. The activities of Ras, Raf-1, and p-CREB in the Ras complex