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Sample records for avascular pancreatic islets

  1. FEM-based oxygen consumption and cell viability models for avascular pancreatic islets

    Directory of Open Access Journals (Sweden)

    Buchwald Peter

    2009-04-01

    Full Text Available Abstract Background The function and viability of cultured, transplanted, or encapsulated pancreatic islets is often limited by hypoxia because these islets have lost their vasculature during the isolation process and have to rely on gradient-driven passive diffusion, which cannot provide adequate oxygen transport. Pancreatic islets (islets of Langerhans are particularly susceptible due to their relatively large size, large metabolic demand, and increased sensitivity to hypoxia. Here, finite element method (FEM based multiphysics models are explored to describe oxygen transport and cell viability in avascular islets both in static and in moving culture media. Methods Two- and three-dimensional models were built in COMSOL Multiphysics using the convection and diffusion as well as the incompressible Navier-Stokes fluid dynamics application modes. Oxygen consumption was assumed to follow Michaelis-Menten-type kinetics and to cease when local concentrations fell below a critical threshold; in a dynamic model, it was also allowed to increase with increasing glucose concentration. Results Partial differential equation (PDE based exploratory cellular-level oxygen consumption and cell viability models incorporating physiologically realistic assumptions have been implemented for fully scaled cell culture geometries with 100, 150, and 200 μm diameter islets as representative. Calculated oxygen concentrations and intra-islet regions likely to suffer from hypoxia-related necrosis obtained for traditional flask-type cultures, oxygen-permeable silicone-rubber membrane bottom cultures, and perifusion chambers with flowing media and varying incoming glucose levels are presented in detail illustrated with corresponding colour-coded figures and animations. Conclusion Results of the computational models are, as a first estimate, in good quantitative agreement with existing experimental evidence, and they confirm that during culture, hypoxia is often a problem for

  2. Pancreatic Islet Transplantation

    Science.gov (United States)

    ... Diabetes, Gum Disease, and Other Dental Problems Diabetic Eye Disease Diabetes and Pregnancy Financial Help for Diabetes Care Diabetes Statistics Pancreatic Islet Transplantation What are pancreatic islets? Pancreatic islets, also called ...

  3. Pancreatic islet transplantation

    Directory of Open Access Journals (Sweden)

    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

  4. Optogenetic Control of Pancreatic Islets.

    Science.gov (United States)

    Reinbothe, Thomas M; Mollet, Inês G

    2016-01-01

    In light of the emerging diabetes epidemic, new experimental approaches in islet research are needed to elucidate the mechanisms behind pancreatic islet dysfunction and to facilitate the development of more effective therapies. Optogenetics has created numerous new experimental tools enabling us to gain insights into processes little was known about before. The spatial and temporal precision that it can achieve is also attractive for studying the cells of the pancreatic islet and we set out to explore the possibilities of this technology for our purposes. We here describe how to use the islets of an "optogenetic beta-cell" mouse line in islet batch incubations and Ca(2+) imaging experiments. This protocol enables light-induced insulin release and provides an all-optical solution to control and measure intracellular Ca(2+) levels in pancreatic beta-cells. The technique is easy to set up and provides a useful tool for controlling the activity of distinct islet cell populations. PMID:26965119

  5. Pancreatic Islet Transplantation

    Science.gov (United States)

    ... which islets from the pancreas of a deceased organ donor are purified, processed, and transferred into another person. ... in 2011 there were about 8,000 deceased organ donors available in the United States. 2 However, only ...

  6. Unraveling pancreatic islet biology by quantitative proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianying; Dann, Geoffrey P.; Liew, Chong W.; Smith, Richard D.; Kulkarni, Rohit N.; Qian, Weijun

    2011-08-01

    The pancreatic islets of Langerhans play a critical role in maintaining blood glucose homeostasis by secreting insulin and several other important peptide hormones. Impaired insulin secretion due to islet dysfunction is linked to the pathogenesis underlying both Type 1 and Type 2 diabetes. Over the past 5 years, emerging proteomic technologies have been applied to dissect the signaling pathways that regulate islet functions and gain an understanding of the mechanisms of islet dysfunction relevant to diabetes. Herein, we briefly review some of the recent quantitative proteomic studies involving pancreatic islets geared towards gaining a better understanding of islet biology relevant to metabolic diseases.

  7. Pancreatic islet cell tumor

    Science.gov (United States)

    ... may include: Fasting glucose level Gastrin level Glucose tolerance test Secretin stimulation test for pancreas Blood glucagon ... PhD, and the A.D.A.M. Editorial team. Related MedlinePlus Health Topics Pancreatic Cancer Browse the ...

  8. Organ culture studies for pancreatic islet transplantation

    International Nuclear Information System (INIS)

    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

  9. File list: Pol.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Pan.10.AllAg.Pancreatic_islets hg19 RNA polymerase Pancreas Pancreatic islets h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Pan.10.AllAg.Pancreatic_islets.bed ...

  10. File list: Pol.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Pan.20.AllAg.Pancreatic_islets hg19 RNA polymerase Pancreas Pancreatic islets h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Pan.20.AllAg.Pancreatic_islets.bed ...

  11. File list: Pol.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Pan.05.AllAg.Pancreatic_islets hg19 RNA polymerase Pancreas Pancreatic islets h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Pan.05.AllAg.Pancreatic_islets.bed ...

  12. File list: Pol.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Pan.50.AllAg.Pancreatic_islets hg19 RNA polymerase Pancreas Pancreatic islets h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Pan.50.AllAg.Pancreatic_islets.bed ...

  13. Radio-immunoassay of somatostatin from isolated rat pancreatic islets

    International Nuclear Information System (INIS)

    Certain aspects of radio-immunoassay of somatostatin from isolated rat pancreatic islets are described. Somatostatin-14, and not somatostatin-28, is secreted from isolated rat pancreatic islets. Less somatostatin secretion is measured per islet owing to purity of tracer in the radio-immunoassay. Theophylline apparently cross-reacts with somatostatin in the assay described, and this has to be taken into consideration when studying somatostatin release induced by theophylline in isolated islets. (author)

  14. Current status and outlook of pancreatic islets transplantation research

    International Nuclear Information System (INIS)

    Diabetes is a common disease, severely harmful to the human's health and life quality. The pancreatic islets transplantation can correct the patient's hyperglycemia, stop or even reverse the progress of the complication and thus decrease the mortality of diabetic patients. It is the most safe and efficient therapy for diabetes. Since the Edmonton Protocol got success in pancreatic islet transplantation in 2000, it has been more and more interested because of its great clinical curative effect. Research strategy of islet transplantation is now focussed on increasing the acquired islets with normal viability, selecting the best transplantation pathway, and improving the immunosuppression protocol. The shortage of human pancreatic donor is an ever unsolved problem in clinical application. The potential resolutions may include acquisition from xenogenic-islets; islets originated from stem cells, and islets from the living-donor human pancreas. The islets transplantation will open a new application field for interventional radiology. (authors)

  15. Historical Background of Pancreatic Islet Isolation.

    Science.gov (United States)

    Ramírez-Domínguez, Miriam

    2016-01-01

    Until the discovery of insulin in the twentieth century, diabetes mellitus was a mortal disease with an unclear origin and physiology. Despite the appearance of the concept in an Egyptian papyrus dated c.1550 BC, and the documentation of its study by ancient Chinese, the term "diabetes" was only coined by the Greek Aretaeus in the second century AD. In Europe, the study of diabetes was largely ignored until the seventeenth century, when the characteristic sweet flavor of diabetic urine was first described. However, the link between diabetes and the pancreas was not discovered until 1889 by Minkowski and von Mering, long after the first description of the pancreatic islets by Paul Langerhans in 1869. One of the most significant milestones in the field was the discovery of insulin by Banting and collaborators in 1922, which led to the therapeutic development of insulin administration as a life-saving intervention for type 1 diabetic patients. On the other hand, the isolation of islets was first reported by Bensley in 1911, a critical technical achievement that paved the way for clinical islet transplantation. Here we discuss the history of islet isolation, since the firsts studies of diabetes by ancient civilizations to the birth and parallel evolution of islet isolation and transplantation. PMID:27586418

  16. Mesenchymal Stem Cells as Feeder Cells for Pancreatic Islet Transplants

    OpenAIRE

    Sordi, Valeria; Piemonti, Lorenzo

    2010-01-01

    Allogeneic islet transplantation serves as a source of insulin-secreting beta-cells for the maintenance of normal glucose levels and treatment of diabetes. However, limited availability of islets, high rates of islet graft failure, and the need for life-long non-specific immunosuppressive therapy are major obstacles to the widespread application of this therapeutic approach. To overcome these problems, pancreatic islet transplantation was recently suggested as a potential target of the "thera...

  17. Islet amyloid polypeptide in pancreatic islets from type 2 diabetic subjects

    OpenAIRE

    Tomita, Tatsuo

    2012-01-01

    Aims/hypothesis: Islet amyloid polypeptide (IAPP) is a chief constituent of amyloid deposits in pancreatic islets, characteristic histopathology for type 2 diabetes. The goal of this study was to analyze islet cell composition in diabetic islets for the process of transforming water-soluble IAPP in β-cells to water-insoluble amyloid deposits by Immunocytochemical staining using different dilutions of anti-IAPP antibody. IAPP in β-cell granules may initiate β-cell necrosis through apoptosis to...

  18. Multifunctional in vivo imaging of pancreatic islets during diabetes development.

    Science.gov (United States)

    Li, Ge; Wu, Binlin; Ward, Meliza G; Chong, Angie C N; Mukherjee, Sushmita; Chen, Shuibing; Hao, Mingming

    2016-07-15

    Pancreatic islet dysfunction leading to insufficient glucose-stimulated insulin secretion triggers the clinical onset of diabetes. How islet dysfunction develops is not well understood at the cellular level, partly owing to the lack of approaches to study single islets longitudinally in vivo Here, we present a noninvasive, high-resolution system to quantitatively image real-time glucose metabolism from single islets in vivo, currently not available with any other method. In addition, this multifunctional system simultaneously reports islet function, proliferation, vasculature and macrophage infiltration in vivo from the same set of images. Applying our method to a longitudinal high-fat diet study revealed changes in islet function as well as alternations in islet microenvironment. More importantly, this label-free system enabled us to image real-time glucose metabolism directly from single human islets in vivo for the first time, opening the door to noninvasive longitudinal in vivo studies of healthy and diabetic human islets. PMID:27270669

  19. Ectopic pancreatic islets in Splenic hilum and peripancreatic fat

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    Vasishta RK

    2008-01-01

    Full Text Available Abstract The presence of pancreatic islets alone in the peripancreatic region and splenic hilum is an uncommon occurrence. Herein, we describe their presence in this rare location.

  20. Pancreatic and peri-pancreatic lesions mimic pancreatic islet cell tumor in multidetector computed tomography

    Institute of Scientific and Technical Information of China (English)

    XUE Hua-dan; LIU Wei; XIAO Yu; SUN Hao; WANG Xuan; LEI Jing; JIN Zheng-yu

    2011-01-01

    Objective This pictorial review aimed to summarize the most possible differential diagnosis of pancreatic islet cell tumor (PICT).Data sources Data used in this review were mainly from Medline and Pubmed in English. And all clinical images in this review were from Department of Radiology, Peking Union Medical College Hospital, Beijing, China.Study selection Cases of pancreatic cystadenoma, solid pseudo-papillary tumor of the pancreas, pancreatic metastasis, pancreatic adenocarcinoma, para-pancreatic neuroendocrine tumors, Castleman disease, gastrointestinal stromal tumor, splenic artery aneurysm and accessory spleen were selected in this pictorial review for differential diagnosis of PICT.Results Careful analysis of imaging features and correlation with the clinical manifestations may allow a more specific diagnosis. It is also important that the radiologist is familiar with the anatomic variants and disease entities which mimic pancreatic islet cell tumor in order to avoid an improper treatment protocol.Conclusions Many congenital anatomic variants or other pancreatic and peri-pancreatic diseases may mimic MDCT appearance of pancreatic islet cell tumor. Radiological, clinical and pathological characteristics should be considered for the final diagnosis.

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

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    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.

  2. Tacrolimus inhibits the revascularization of isolated pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Ryuichi Nishimura

    Full Text Available AIMS: Immunosuppressive drugs could be crucial factors for a poor outcome after islet allotransplantation. Unlike rapamycin, the effects of tacrolimus, the current standard immunosuppressant used in islet transplantation, on graft revascularization remain unclear. We examined the effects of tacrolimus on islet revascularization using a highly sensitive imaging system, and analyzed the gene expression in transplanted islets by introducing laser microdissection techniques. METHODS: Islets isolated from C57BL/6-Tg (CAG-EGFP mice were transplanted into the nonmetallic dorsal skinfold chamber on the recipients. Balb/c athymic mice were used as recipients and were divided into two groups: including a control group (n = 9 and tacrolimus-treated group (n = 7. The changes in the newly-formed vessels surrounding the islet grafts were imaged and semi-quantified using multi-photon laser-scanning microscopy and a Volocity system. Gene expression in transplanted islets was analyzed by the BioMark dynamic system. RESULTS: The revascularization process was completed within 14 days after pancreatic islet transplantation at subcutaneous sites. The newly-formed vascular volume surrounding the transplanted islets in the tacrolimus-treated group was significantly less than that in the control group (p<0.05. Although the expression of Vegfa (p<0.05 and Ccnd1 (p<0.05 was significantly upregulated in the tacrolimus-treated group compared with that of the control group, no differences were observed between the groups in terms of other types of gene expression. CONCLUSIONS: The present study demonstrates that tacrolimus inhibits the revascularization of isolated pancreatic islets without affecting the characteristics of the transplanted grafts. Further refinements of this immunosuppressive regimen, especially regarding the revascularization of islet grafts, could improve the outcome of islet allotransplantation.

  3. File list: InP.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Pan.05.AllAg.Pancreatic_islets hg19 Input control Pancreas Pancreatic islets SR...5,SRX375327,SRX340803,SRX375320,SRX340794,SRX026707 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Pan.05.AllAg.Pancreatic_islets.bed ...

  4. File list: NoD.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Pan.10.AllAg.Pancreatic_islets hg19 No description Pancreas Pancreatic islets E.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Pan.10.AllAg.Pancreatic_islets.bed ...

  5. File list: DNS.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Pan.10.AllAg.Pancreatic_islets hg19 DNase-seq Pancreas Pancreatic islets ERX873...854,ERX873852,SRX026725,SRX026723,SRX026724 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Pan.10.AllAg.Pancreatic_islets.bed ...

  6. File list: NoD.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Pan.50.AllAg.Pancreatic_islets hg19 No description Pancreas Pancreatic islets E.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Pan.50.AllAg.Pancreatic_islets.bed ...

  7. File list: InP.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Pan.10.AllAg.Pancreatic_islets hg19 Input control Pancreas Pancreatic islets SR...3,SRX340803,SRX375327,SRX340794,SRX026707,SRX375320 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Pan.10.AllAg.Pancreatic_islets.bed ...

  8. File list: Oth.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Pan.05.AllAg.Pancreatic_islets hg19 TFs and others Pancreas Pancreatic islets S...RX026714,SRX026702,SRX026720,SRX026719,SRX026721,SRX026706 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Pan.05.AllAg.Pancreatic_islets.bed ...

  9. File list: ALL.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Pan.20.AllAg.Pancreatic_islets hg19 All antigens Pancreas Pancreatic islets ERX...SRX026709,SRX026714,SRX026718,ERX321654,ERX321649,SRX026724 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Pan.20.AllAg.Pancreatic_islets.bed ...

  10. File list: His.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.50.AllAg.Pancreatic_islets hg19 Histone Pancreas Pancreatic islets SRX37532...0804,SRX340799,SRX340802,SRX340809,SRX026708,SRX026713 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.50.AllAg.Pancreatic_islets.bed ...

  11. File list: Oth.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Pan.50.AllAg.Pancreatic_islets hg19 TFs and others Pancreas Pancreatic islets S...RX026719,SRX026702,SRX026720,SRX026706,SRX026721,SRX026714 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Pan.50.AllAg.Pancreatic_islets.bed ...

  12. File list: NoD.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Pan.20.AllAg.Pancreatic_islets hg19 No description Pancreas Pancreatic islets E.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Pan.20.AllAg.Pancreatic_islets.bed ...

  13. File list: InP.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Pan.20.AllAg.Pancreatic_islets hg19 Input control Pancreas Pancreatic islets SR...5,SRX375327,SRX340803,SRX340794,SRX026707,SRX375320 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Pan.20.AllAg.Pancreatic_islets.bed ...

  14. File list: Oth.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Pan.20.AllAg.Pancreatic_islets hg19 TFs and others Pancreas Pancreatic islets S...RX026719,SRX026702,SRX026720,SRX026706,SRX026721,SRX026714 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Pan.20.AllAg.Pancreatic_islets.bed ...

  15. File list: DNS.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Pan.05.AllAg.Pancreatic_islets hg19 DNase-seq Pancreas Pancreatic islets ERX873...854,ERX873852,SRX026723,SRX026725,SRX026724 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Pan.05.AllAg.Pancreatic_islets.bed ...

  16. File list: DNS.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Pan.50.AllAg.Pancreatic_islets hg19 DNase-seq Pancreas Pancreatic islets ERX873...854,ERX873852,SRX026725 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Pan.50.AllAg.Pancreatic_islets.bed ...

  17. File list: His.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.05.AllAg.Pancreatic_islets hg19 Histone Pancreas Pancreatic islets SRX37532...0809,SRX340814,SRX375319,SRX026709,SRX375326,SRX026718 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.05.AllAg.Pancreatic_islets.bed ...

  18. File list: Unc.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Pan.20.AllAg.Pancreatic_islets hg19 Unclassified Pancreas Pancreatic islets SRX...016328,SRX016329,SRX016330 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Pan.20.AllAg.Pancreatic_islets.bed ...

  19. File list: His.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.20.AllAg.Pancreatic_islets hg19 Histone Pancreas Pancreatic islets SRX37532...0790,SRX026716,SRX026713,SRX026708,SRX026709,SRX026718 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.20.AllAg.Pancreatic_islets.bed ...

  20. File list: NoD.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Pan.05.AllAg.Pancreatic_islets hg19 No description Pancreas Pancreatic islets E.../dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Pan.05.AllAg.Pancreatic_islets.bed ...

  1. File list: ALL.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Pan.50.AllAg.Pancreatic_islets hg19 All antigens Pancreas Pancreatic islets ERX...SRX026707,SRX375320,SRX026708,SRX026713 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Pan.50.AllAg.Pancreatic_islets.bed ...

  2. File list: ALL.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Pan.10.AllAg.Pancreatic_islets hg19 All antigens Pancreas Pancreatic islets SRX...ERX321646,ERX321661,SRX375319,SRX026706,SRX026709,SRX026718 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Pan.10.AllAg.Pancreatic_islets.bed ...

  3. File list: ALL.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Pan.05.AllAg.Pancreatic_islets hg19 All antigens Pancreas Pancreatic islets SRX...SRX375319,ERX321669,SRX026709,SRX375326,SRX026706,SRX026718 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Pan.05.AllAg.Pancreatic_islets.bed ...

  4. File list: DNS.Pan.20.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Pan.20.AllAg.Pancreatic_islets hg19 DNase-seq Pancreas Pancreatic islets ERX873...854,ERX873852,SRX026725,SRX026723,SRX026724 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Pan.20.AllAg.Pancreatic_islets.bed ...

  5. File list: Unc.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Pan.50.AllAg.Pancreatic_islets hg19 Unclassified Pancreas Pancreatic islets SRX...016328,SRX016329,SRX016330 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Pan.50.AllAg.Pancreatic_islets.bed ...

  6. File list: InP.Pan.50.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Pan.50.AllAg.Pancreatic_islets hg19 Input control Pancreas Pancreatic islets SR...5,SRX340795,SRX340793,SRX340803,SRX026707,SRX375320 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Pan.50.AllAg.Pancreatic_islets.bed ...

  7. File list: Unc.Pan.05.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Pan.05.AllAg.Pancreatic_islets hg19 Unclassified Pancreas Pancreatic islets SRX...016328,SRX016329,SRX016330 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Pan.05.AllAg.Pancreatic_islets.bed ...

  8. File list: His.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.10.AllAg.Pancreatic_islets hg19 Histone Pancreas Pancreatic islets SRX37532...0804,SRX026716,SRX375326,SRX375319,SRX026709,SRX026718 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Pan.10.AllAg.Pancreatic_islets.bed ...

  9. File list: Oth.Pan.10.AllAg.Pancreatic_islets [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Pan.10.AllAg.Pancreatic_islets hg19 TFs and others Pancreas Pancreatic islets S...RX026702,SRX026719,SRX026720,SRX026721,SRX026714,SRX026706 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Pan.10.AllAg.Pancreatic_islets.bed ...

  10. Human Pancreatic Islet Isolation: Part II: Purification and Culture of Human Islets

    OpenAIRE

    Qi, Meirigeng; Barbaro, Barbara; Wang, Shusen; Wang, Yong; Hansen, Mike; Oberholzer, Jose

    2009-01-01

    Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients 1, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet ...

  11. Mesobiliverdin IXα Enhances Rat Pancreatic Islet Yield and Function.

    Science.gov (United States)

    Ito, Taihei; Chen, Dong; Chang, Cheng-Wei Tom; Kenmochi, Takashi; Saito, Tomonori; Suzuki, Satoshi; Takemoto, Jon Y

    2013-01-01

    The aims of this study were to produce mesobiliverdin IXα, an analog of anti-inflammatory biliverdin IXα, and to test its ability to enhance rat pancreatic islet yield for allograft transplantation into diabetic recipients. Mesobiliverdin IXα was synthesized from phycocyanobilin derived from cyanobacteria, and its identity and purity were analyzed by chromatographic and spectroscopic methods. Mesobiliverdin IXα was a substrate for human NADPH biliverdin reductase. Excised Lewis rat pancreata infused with mesobiliverdin IXα and biliverdin IXα-HCl (1-100 μM) yielded islet equivalents as high as 86.7 and 36.5%, respectively, above those from non-treated controls, and the islets showed a high degree of viability based on dithizone staining. When transplanted into livers of streptozotocin-induced diabetic rats, islets from pancreata infused with mesobiliverdin IXα lowered non-fasting blood glucose (BG) levels in 55.6% of the recipients and in 22.2% of control recipients. In intravenous glucose tolerance tests, fasting BG levels of 56 post-operative day recipients with islets from mesobiliverdin IXα infused pancreata were lower than those for controls and showed responses that indicate recovery of insulin-dependent function. In conclusion, mesobiliverdin IXα infusion of pancreata enhanced yields of functional islets capable of reversing insulin dysfunction in diabetic recipients. Since its production is scalable, mesobiliverdin IXα has clinical potential as a protectant of pancreatic islets for allograft transplantation. PMID:23630498

  12. Mesobiliverdin-IXα Enhances Rat Pancreatic Islet Yield and Function

    Directory of Open Access Journals (Sweden)

    Taihei eIto

    2013-04-01

    Full Text Available The aims of this study were to produce mesobiliverdin IXα, an analog of anti-inflammatory biliverdin IXα and to test its ability to enhance rat pancreatic islet yield for allograft transplantation into diabetic recipients. Mesobiliverdin IXα was synthesized from phycocyanobilin derived from cyanobacteria, and its identity and purity were analyzed by chromatographic and spectroscopic methods. Mesobiliverdin IXα was a substrate for human NADPH biliverdin reductase. Excised Lewis rat pancreata infused with mesobiliverdin IXα and biliverdin IXα-HCl (1 – 100 μM yielded islet equivalents as high as 86.7% and 36.5%, respectively, above those from non-treated controls, and the islets showed a high degree of viability based on dithizone staining. When transplanted into livers of streptozotocin-induced diabetic rats, islets from pancreata infused with mesobiliverdin IXα lowered non-fasting blood glucose levels in 55.6% of the recipients and in 22.2% of control recipients. In intravenous glucose tolerance tests, fasting blood glucose levels of 56 post-operative day recipients with islets from mesobiliverdin IXα infused pancreata were lower than those for controls and showed responses that indicate recovery of insulin-dependent function. In conclusion, mesobiliverdin IXα infusion of pancreata enhanced yields of functional islets capable of reversing insulin dysfunction in type 2 diabetic recipients. Since its production is scalable, mesobiliverdin IXα has clinical potential as a protectant of pancreatic islets for allograft transplantation.

  13. Isolation of Pancreatic Islets from Nonhuman Primates.

    Science.gov (United States)

    Berman, Dora M

    2016-01-01

    Nonhuman primates (NHP) constitute a highly relevant pre-clinical animal model to develop strategies for beta cell replacement. The close phylogenetic and immunologic relationship between NHP and humans results in cross-reactivity of various biological agents with NHP cells, as well as a very similar cytoarchitecture between islets from human and NHP that is strikingly different from that observed in rodent islets. The composition and location of endocrine cells in human or NHP islets, randomly distributed and associated with blood vessels, have functional consequences and a predisposition for paracrine interactions. Furthermore, translation of approaches that proved successful in rodent models to the clinic has been limited. Consequently, data collected from NHP studies can form the basis for an IND submission to the FDA. This chapter describes in detail the key aspects for isolation of islets from NHP, from organ procurement up to assessment of islet function, comparing and emphasizing the similarities between isolation procedures for human and NHP islets. PMID:27586422

  14. Dynamics and Synchrony of Pancreatic beta-cells and Islets

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram

    2006-01-01

    biological hypotheses. The subjects addressed are: Quasi-steady-state approximations of enzyme reactions, the effect of noise on bursting electrical behavior, exciation wave propagation in pancreatic islets, intra- and inter-islet synchronization and pulsatile insulin secretion, and mitochondrial dynamics.......Pancreatic beta-cells secrete insulin in response to raised glucose levels. Malfunctioning of this system plays an important role in the metabolic disease diabetes. The biological steps from glucose stimulus to the final release of insulin are incompletely understood, and a more complete...

  15. Generation of pancreatic islet cells from human embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Efficiently obtaining functional pancreatic islet cells derived from human embryonic stem(hES) cells not only provides great potential to solve the shortage of islets sources for type I diabetes cell therapy,but also benefits the study of the development of the human pancreas and diabetes pathology.In 2001,hES cells were reported to have the capacity to generate insulin-producing cells by spontaneous differentiation in vitro.Since then,many strategies(such as overexpression of key transcription factors,delivery of key proteins for pancreatic development,co-transplantation of differentiated hES cells along with fetal pancreas,stepwise differentiation by mimicking in vivo pancreatic development) have been employed in order to induce the differentiation of pancreatic islet cells from hES cells.Moreover,patient-specific induced pluripotent stem(iPS) cells can be generated by reprogramming somatic cells.iPS cells have characteristics similar to those of ES cells and offer a new cell source for type I diabetes cell therapy that reduces the risk of immunologic rejection.In this review,we summarize the recent progress made in the differentiation of hES and iPS cells into functional pancreatic islet cells and discuss the challenges for their future study.

  16. Controlled aggregation of primary human pancreatic islet cells leads to glucose-responsive pseudoislets comparable to native islets

    NARCIS (Netherlands)

    Hilderink, Janneke; Spijker, Siebe; Carlotti, Françoise; Lange, Lydia; Engelse, Marten; van Blitterswijk, Clemens; de Koning, Eelco; Karperien, Marcel; van Apeldoorn, Aart

    2015-01-01

    Clinical islet transplantation is a promising treatment for patients with type 1 diabetes. However, pancreatic islets vary in size and shape affecting their survival and function after transplantation because of mass transport limitations. To reduce diffusion restrictions and improve islet cell surv

  17. Human pancreatic islet progenitor cells demonstrate phenotypic plasticity in vitro

    Indian Academy of Sciences (India)

    Maithili P Dalvi; Malati R Umrani; Mugdha V Joglekar; Anandwardhan A Hardikar

    2009-10-01

    Phenotypic plasticity is a phenomenon that describes the occurrence of 2 or more distinct phenotypes under diverse conditions. This article discusses the work carried out over the past few years in understanding the potential of human pancreatic islet-derived progenitors for cell replacement therapy in diabetes. The phenotypic plasticity exhibited by pancreatic progenitors during reversible epithelial-to-mesenchymal transition (EMT) and possible role of microRNAs in regulation of this process is also presented herein.

  18. Generation of pancreatic islet cells from human embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG DongHui; JIANG Wei; SHI Yan; DENG HongKui

    2009-01-01

    Efficiently obtaining functional pancreaUc islet cells derived from human embryonic stem (hES) cells not only provides great potential to solve the shortage of islets sources for type I diabetes cell therapy,but also benefits the study of the development of the human pancreas and diabetes pathology. In 2001,hES cells were reported to have the capacity to generate insulin-producing cells by spontaneous differentiation in vitro. Since then, many strategies (such as overexpression of key transcription factors,delivery of key proteins for pancreatic development, co-transplantation of differentiated hES cells along with fetal pancreas, stepwise differentiation by mimicking in vivo pancreatic development) have been employed in order to induce the differentiation of pancreatic islet cells from hES cells. Moreover, patient-specific induced pluripotent stem (iPS) cells can be generated by reprogramming somatic cells.iPS cells have characteristics similar to those of ES cells and offer a new cell source for type I diabetes cell therapy that reduces the risk of immunologic rejection. In this review, we summarize the recent progress made in the differentiation of hES and iPS cells into functional pancreatic islet cells and discuss the challenges for their future study.

  19. Pancreatic Islets: Methods for Isolation and Purification of Juvenile and Adult Pig Islets.

    Science.gov (United States)

    Brandhorst, Heide; Johnson, Paul R V; Brandhorst, Daniel

    2016-01-01

    The current situation of organ transplantation is mainly determined by the disbalance between the number of available organs and the number of patients on the waiting list. This obvious dilemma might be solved by the transplantation of porcine organs into human patients. The metabolic similarities which exist between both species made pancreatic islets of Langerhans to that donor tissue which will be most likely transplanted in human recipients. Nevertheless, the successful isolation of significant yields of viable porcine islets is extremely difficult and requires extensive experiences in the field. This review is focussing on the technical challenges, pitfalls and particularities that are associated with the isolation of islets from juvenile and adult pigs considering donor variables that can affect porcine islet isolation outcome. PMID:27586421

  20. Hexose metabolism in pancreatic islets: the Pasteur effect.

    Science.gov (United States)

    Malaisse, W J; Rasschaert, J; Zähner, D; Sener, A

    1988-02-01

    In rat pancreatic islets, hypoxia severely decreased both the oxidation of D-[U-14C]glucose and the release of insulin evoked by D-glucose. The production of [14C]lactate was increased in the hypoxic islets, the relative magnitude of such an increment being greater at low (2.8 mM) than high (8.3 and 16.7 mM) D-glucose concentrations. Hypoxia increased the detritiation of D-[5-3H]glucose at low glucose concentration (2.8 mM), failed to affect 3H2O production at an intermediate glucose level (8.3 mM), and inhibited the utilization of D-[5-3H]glucose at a higher hexose concentration (16.7 mM). In tumoral islet cells (RINm5F line) exposed to 16.7 mM D-glucose, hypoxia decreased D-[U-14C]glucose oxidation to the same extent as in normal islet cells, but increased the production of [14C]lactate and 3H2O to a greater extent than in normal islets. These findings indicate that the Pasteur effect is operative in islet cells. The experimental data also suggest that, under normal conditions of oxygenation, high concentrations of D-glucose lead to both activation of phosphofructokinase and stimulation of mitochondrial oxidative events in normal, but not tumoral, islet cells.

  1. Binding of insulin to rat pancreatic islets: comparison between pancreatic human insulin and biosynthetic human insulin

    Energy Technology Data Exchange (ETDEWEB)

    Verspohl, E.J.; Ammon, H.P.

    Human pancreatic insulin, biosynthetic human insulin (BHI), and pork insulin were compared in terms of their binding characteristics to insulin receptors on rat pancreatic islets. There was no difference in binding or on biologic effect, i.e., ability to inhibit insulin secretion.

  2. RNA-sequencing of WFS1-deficient pancreatic islets.

    Science.gov (United States)

    Ivask, Marilin; Hugill, Alison; Kõks, Sulev

    2016-04-01

    Wolfram syndrome, an autosomal recessive disorder characterized by juvenile-onset diabetes mellitus and optic atrophy, is caused by mutations in theWFS1gene.WFS1encodes an endoplasmic reticulum resident transmembrane protein. TheWfs1-null mice exhibit progressive insulin deficiency and diabetes. The aim of this study was to describe the insulin secretion and transcriptome of pancreatic islets inWFS1-deficient mice.WFS1-deficient (Wfs1KO) mice had considerably less pancreatic islets than heterozygous (Wfs1HZ) or wild-type (WT) mice. Wfs1KOpancreatic islets secreted less insulin after incubation in 2 and 10 mmol/L glucose and with tolbutamide solution compared toWTand Wfs1HZislets, but not after stimulation with 20 mmol/L glucose. Differences in proinsulin amount were not statistically significant although there was a trend that Wfs1KOhad an increased level of proinsulin. After incubation in 2 mmol/L glucose solution the proinsulin/insulin ratio in Wfs1KOwas significantly higher than that ofWTand Wfs1HZRNA-seq from pancreatic islets found melastatin-related transient receptor potential subfamily member 5 protein gene (Trpm5) to be downregulated inWFS1-deficient mice. Functional annotation ofRNAsequencing results showed thatWFS1 deficiency influenced significantly the pathways related to tissue morphology, endocrine system development and function, molecular transport network. PMID:27053292

  3. Immune tolerance in pancreatic islet xenotransplantation

    Institute of Scientific and Technical Information of China (English)

    Tian-Hua Tang; Chun-Lin Li; Xin Li; Feng-Qin Jiang; Yu-Kun Zhang; Hai-Quan Ren; Shan-Shan Su; Guo-Sheng Jiang

    2004-01-01

    AIM: To observe the effect of tail vein injection with donor hepatocytes and/or splenocytes on the islet xenotransplantation rejection.METHODS: New-bom male pigs and BALB/C mice were selected as donors and recipients respectively. Islet xenotransplantation was performed in recipients just after the third time of tail vein injection with donor hepatocytes and/or splenocytes.Macrophage phagocytosis, NK(natural killing cell) killing activity, T lymphocyte transforming function of spleen cells,antibody forming function of B lymphocytes, and T lymphocyte subsets were taken to monitor transplantation rejection. The effects of this kind of transplantation were indicated as variation of blood glucose and survival days of recipients.RESULTS: The results showed that streptozotocin (STZ) could induce diabetes mellitus models of mice. The preinjection of donor hepatocytes, splenocytes or their mixture by tail vein injection was effective in preventing donor islet transplantation from rejection, which was demonstrated by the above-mentioned immunological marks. Each group of transplantation could decrease blood glucose in recipients and increase survival days. Pre-injection of mixture of donor hepatocytes and splenocytes was more effective in preventing rejection as compared with that of donor hepatocyte or splenocyte pre-injection respectively.CONCLUSION: Pre-injection of donor hepatocytes, splenocytes or their mixture before donor islet transplantation is a good way in preventing rejection.

  4. Implantation-Site Dependent Differences in Engraftment and Function of Transplanted Pancreatic Islets

    OpenAIRE

    Lau, Joey

    2008-01-01

    Transplanting pancreatic islets into the liver through the portal vein is currently the most common procedure in clinical islet transplantations for treating patients with brittle type 1 diabetes. However, most islet grafts fail within a 5-year period necessitating retransplantation. The vascular connections are disrupted at islet isolation and implanted islets depend on diffusion of oxygen and nutrients in the immediate posttransplantation period. Rapid and efficient revascularization is of ...

  5. Assessment of pancreatic islet cell function and survival

    OpenAIRE

    Köhler, Martin

    2015-01-01

    Function and survival of pancreatic islet insulin-producing beta-cells (β-cells) and glucagonproducing alpha-cells (α-cells) were studied, and methods for this purpose were developed or refined. Dynamic control of glucose metabolism is essential for β-cell stimulus-secretion coupling. ATP is an important metabolic parameter and therefore we set up a technique to monitor dynamic changes of ATP in insulin-producing cells using luciferase bioluminescence at the level of single...

  6. Pancreatic islet insulin secretion and metabolism in adult rats malnourished during neonatal life

    DEFF Research Database (Denmark)

    Barbosa, Francisco B; Capito, Kirsten; Kofod, Hans;

    2002-01-01

    Pancreatic islets were isolated from rats that had been nursed by dams fed with a control or an 8.7% protein diet during the first 12 d of the lactation period. Glucose-induced insulin secretion from islets in the 8.7% protein group was reduced 50%. The islet insulin and DNA content were similar,...

  7. Transcriptional Regulation of Chemokine Genes: A Link to Pancreatic Islet Inflammation?

    Directory of Open Access Journals (Sweden)

    Susan J. Burke

    2015-05-01

    Full Text Available Enhanced expression of chemotactic cytokines (aka chemokines within pancreatic islets likely contributes to islet inflammation by regulating the recruitment and activation of various leukocyte populations, including macrophages, neutrophils, and T-lymphocytes. Because of the powerful actions of these chemokines, precise transcriptional control is required. In this review, we highlight what is known about the signals and mechanisms that govern the transcription of genes encoding specific chemokine proteins in pancreatic islet β-cells, which include contributions from the NF-κB and STAT1 pathways. We further discuss increased chemokine expression in pancreatic islets during autoimmune-mediated and obesity-related development of diabetes.

  8. A double mechanism for the mesenchymal stem cells' positive effect on pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Arianna Scuteri

    Full Text Available The clinical usability of pancreatic islet transplantation for the treatment of type I diabetes, despite some encouraging results, is currently hampered by the short lifespan of the transplanted tissue. In vivo studies have demonstrated that co-transplantation of Mesenchymal Stem Cells (MSCs with transplanted pancreatic islets is more effective with respect to pancreatic islets alone in ensuring glycemia control in diabetic rats, but the molecular mechanisms of this action are still unclear. The aim of this study was to elucidate the molecular mechanisms of the positive effect of MSCs on pancreatic islet functionality by setting up direct, indirect and mixed co-cultures. MSCs were both able to prolong the survival of pancreatic islets, and to directly differentiate into an "insulin-releasing" phenotype. Two distinct mechanisms mediated these effects: i the survival increase was observed in pancreatic islets indirectly co-cultured with MSCs, probably mediated by the trophic factors released by MSCs; ii MSCs in direct contact with pancreatic islets started to express Pdx1, a pivotal gene of insulin production, and then differentiated into insulin releasing cells. These results demonstrate that MSCs may be useful for potentiating pancreatic islets' functionality and feasibility.

  9. Rat pancreatic islet function during prolonged glucose stimulation in vitro : Effect of sex and reproductive state

    NARCIS (Netherlands)

    Moes, H; Koiter, TR

    1997-01-01

    Prolonged stimulation with glucose may induce desensitisation of pancreatic beta-cell function in male rats. The effects of such a treatment on pancreatic islets of pregnant (P) rats, in which beta-cell function is enhanced, were studied in a perifusion design and compared with the effects on islets

  10. Pancreatic islet enhancer clusters enriched in type 2 diabetes risk–associated variants

    Science.gov (United States)

    Mularoni, Loris; Miguel-Escalada, Irene; Akerman, İldem; Tena, Juan J.; Morán, Ignasi; Gómez-Marín, Carlos; van de Bunt, Martijn; Ponsa-Cobas, Joan; Castro, Natalia; Nammo, Takao; Cebola, Inês; García-Hurtado, Javier; Maestro, Miguel Angel; Pattou, François; Piemonti, Lorenzo; Berney, Thierry; Gloyn, Anna L.; Ravassard, Philippe; Skarmeta, José Luis Gómez; Müller, Ferenc; McCarthy, Mark I.; Ferrer, Jorge

    2013-01-01

    Type 2 diabetes affects over 300 million people, causing severe complications and premature death, yet the underlying molecular mechanisms are largely unknown. Pancreatic islet dysfunction is central for type 2 diabetes pathogenesis, and therefore understanding islet genome regulation could provide valuable mechanistic insights. We have now mapped and examined the function of human islet cis-regulatory networks. We identify genomic sequences that are targeted by islet transcription factors to drive islet-specific gene activity, and show that most such sequences reside in clusters of enhancers that form physical 3D chromatin domains. We find that sequence variants associated with type 2 diabetes and fasting glycemia are enriched in these clustered islet enhancers, and identify trait-associated variants that disrupt DNA-binding and islet enhancer activity. Our studies illustrate how islet transcription factors interact functionally with the epigenome, and provide systematic evidence that dysregulation of islet enhancers is relevant to the mechanisms underlying type 2 diabetes. PMID:24413736

  11. Pancreatic islet enhancer clusters enriched in type 2 diabetes risk-associated variants.

    Science.gov (United States)

    Pasquali, Lorenzo; Gaulton, Kyle J; Rodríguez-Seguí, Santiago A; Mularoni, Loris; Miguel-Escalada, Irene; Akerman, Ildem; Tena, Juan J; Morán, Ignasi; Gómez-Marín, Carlos; van de Bunt, Martijn; Ponsa-Cobas, Joan; Castro, Natalia; Nammo, Takao; Cebola, Inês; García-Hurtado, Javier; Maestro, Miguel Angel; Pattou, François; Piemonti, Lorenzo; Berney, Thierry; Gloyn, Anna L; Ravassard, Philippe; Gómez-Skarmeta, José Luis; Müller, Ferenc; McCarthy, Mark I; Ferrer, Jorge

    2014-02-01

    Type 2 diabetes affects over 300 million people, causing severe complications and premature death, yet the underlying molecular mechanisms are largely unknown. Pancreatic islet dysfunction is central in type 2 diabetes pathogenesis, and understanding islet genome regulation could therefore provide valuable mechanistic insights. We have now mapped and examined the function of human islet cis-regulatory networks. We identify genomic sequences that are targeted by islet transcription factors to drive islet-specific gene activity and show that most such sequences reside in clusters of enhancers that form physical three-dimensional chromatin domains. We find that sequence variants associated with type 2 diabetes and fasting glycemia are enriched in these clustered islet enhancers and identify trait-associated variants that disrupt DNA binding and islet enhancer activity. Our studies illustrate how islet transcription factors interact functionally with the epigenome and provide systematic evidence that the dysregulation of islet enhancers is relevant to the mechanisms underlying type 2 diabetes. PMID:24413736

  12. Pancreatic islet cell therapy for type I diabetes: understanding the effects of glucose stimulation on islets in order to produce better islets for transplantation

    Directory of Open Access Journals (Sweden)

    Li Xin

    2007-01-01

    Full Text Available Abstract While insulin replacement remains the cornerstone treatment for type I diabetes mellitus (T1DM, the transplantation of pancreatic islets of Langerhans has the potential to become an important alternative. And yet, islet transplant therapy is limited by several factors, including far too few donor pancreases. Attempts to expand mature islets or to produce islets from stem cells are far from clinical application. The production and expansion of the insulin-producing cells within the islet (so called β cells, or even creating cells that secrete insulin under appropriate physiological control, has proven difficult. The difficulty is explained, in part, because insulin synthesis and release is complex, unique, and not entirely characterized. Understanding β-cell function at the molecular level will likely facilitate the development of techniques to manufacture β-cells from stem cells. We will review islet transplantation, as well as the mechanisms underlying insulin transcription, translation and glucose stimulated insulin release.

  13. 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

  14. Can pancreatic duct-derived progenitors be a source of islet regeneration?

    International Nuclear Information System (INIS)

    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

  15. IL-10 Induction from Implants Delivering Pancreatic Islets and Hyaluronan

    Directory of Open Access Journals (Sweden)

    Paul L. Bollyky

    2013-01-01

    Full Text Available Local induction of pro-tolerogenic cytokines, such as IL-10, is an appealing strategy to help facilitate transplantation of islets and other tissues. Here, we describe a pair of implantable devices that capitalize on our recent finding that hyaluronan (HA promotes IL-10 production by activated T cells. The first device is an injectable hydrogel made of crosslinked HA and heparan sulfate loaded with anti-CD3/anti-CD28 antibodies and IL-2. T cells embedded within this hydrogel prior to polymerization go on to produce IL-10 in vivo. The second device is a bioengineered implant consisting of a polyvinyl alcohol sponge scaffold, supportive collagen hydrogel, and alginate spheres mediating sustained release of HA in fluid form. Pancreatic islets that expressed ovalbumin (OVA antigen were implanted within this device for 14 days into immunodeficient mice that received OVA-specific DO.11.10 T cells and a subsequent immunization with OVA peptide. Splenocytes harvested from these mice produced IL-10 upon re-challenge with OVA or anti-CD3 antibodies. Both of these devices represent model systems that will be used, in future studies, to further evaluate IL-10 induction by HA, with the objective of improving the survival and function of transplanted islets in the setting of autoimmune (type 1 diabetes.

  16. [Xenogeneic cell therapeutics: Treatment of type 1 diabetes using porcine pancreatic islets and islet cells].

    Science.gov (United States)

    Godehardt, Antonia W; Schilling-Leiß, Dagmar; Sanzenbacher, Ralf; Tönjes, Ralf R

    2015-11-01

    In view of the existing shortage of human donor organs and tissues, xenogeneic cell therapeutics (xCT) offer an alternative for adequate treatment. In particular, porcine pancreatic islets and islet cells have already entered the field of experimental therapy for type-1 diabetes mellitus (T1DM) patients. Thereby, xCT depict challenging products with a glance on medical, ethical, and regulatory questions. With cross-species transplantation (xenotransplantation), the risk of immunological graft rejection as well as the risk of infectious transmission of microbial and viral pathogens must be considered. This includes the bidirectional transmission of microorganisms from graft to host as well as from host to graft. Crossing the border of species requires a critical risk-benefit evaluation as well as a thorough longtime surveillance of transplant recipients after treatment. The international legal and regulatory requirements for xCT are inter alia based on the World Health Organization criteria summarized in the Changsha Communiqué (2008). In the European Union, they were reflected by the European Medicines Agency (EMA) Guideline on Xenogeneic Cell-based Medicinal Products following the implementation of the Regulation on Advanced Therapies (ATMP). On the basis of this regulation, the first non-clinical and clinical experiences were obtained for porcine islets. The results suggest that supportive treatment of T1DM risk patients with xCT may be an alternative to established allogeneic organ transplantation in the future.

  17. Metastatic Insulinoma Following Resection of Nonsecreting Pancreatic Islet Cell Tumor

    Directory of Open Access Journals (Sweden)

    Anoopa A. Koshy MD

    2013-01-01

    Full Text Available A 56-year-old woman presented to our clinic for recurrent hypoglycemia after undergoing resection of an incidentally discovered nonfunctional pancreatic endocrine tumor 6 years ago. She underwent a distal pancreatectomy and splenectomy, after which she developed diabetes and was placed on an insulin pump. Pathology showed a pancreatic endocrine neoplasm with negative islet hormone immunostains. Two years later, computed tomography scan of the abdomen showed multiple liver lesions. Biopsy of a liver lesion showed a well-differentiated neuroendocrine neoplasm, consistent with pancreatic origin. Six years later, she presented to clinic with 1.5 years of recurrent hypoglycemia. Laboratory results showed elevated proinsulin, insulin levels, and c-peptide levels during a hypoglycemic episode. Computed tomography scan of the abdomen redemonstrated multiple liver lesions. Repeated transarterial catheter chemoembolization and microwave thermal ablation controlled hypoglycemia. The unusual features of interest of this case include the transformation of nonfunctioning pancreatic endocrine tumor to a metastatic insulinoma and the occurrence of atrial flutter after octreotide for treatment.

  18. Differentiation of embryonic stem cells to insulin-secreting structures similar to pancreatic islets.

    Science.gov (United States)

    Lumelsky, N; Blondel, O; Laeng, P; Velasco, I; Ravin, R; McKay, R

    2001-05-18

    Although the source of embryonic stem (ES) cells presents ethical concerns, their use may lead to many clinical benefits if differentiated cell types can be derived from them and used to assemble functional organs. In pancreas, insulin is produced and secreted by specialized structures, islets of Langerhans. Diabetes, which affects 16 million people in the United States, results from abnormal function of pancreatic islets. We have generated cells expressing insulin and other pancreatic endocrine hormones from mouse ES cells. The cells self-assemble to form three-dimensional clusters similar in topology to normal pancreatic islets where pancreatic cell types are in close association with neurons. Glucose triggers insulin release from these cell clusters by mechanisms similar to those employed in vivo. When injected into diabetic mice, the insulin-producing cells undergo rapid vascularization and maintain a clustered, islet-like organization. PMID:11326082

  19. Profile of blood glucose and ultrastucture of beta cells pancreatic islet in alloxan compound induced rats

    OpenAIRE

    I Nyoman Suarsana; Priosoeryanto, B P; M. Bintang; T. Wresdiyati

    2010-01-01

    Diabetes is marked by elevated levels of blood glucose, and progressive changes of the structure of pancreatic islet histopathology. The objective of this research was to analyse the glucose level and histophatological feature in pancreatic islet in alloxan compound induced rats. A total of ten male Spraque Dawley rats of 2 months old were used in this study. The rats were divided into two groups: (1) negative control group (K-), and (2) positif induced alloxan group (diabetic group =DM). The...

  20. Physical exercise and pancreatic islets: Acute and chronic actions on insulin secretion

    OpenAIRE

    Almeida, Felipe N.; Proença, André R.G.; Chimin, Patrícia; Marçal, Anderson C.; Bessa-Lima, Fábio; Carvalho, Carla R O

    2012-01-01

    Diabetes mellitus (DM) is a great public health problem, which attacks part of the world population, being characterized by an imbalance in body glucose homeostasis. Physical exercise is pointed as a protective agent and is also recommended to people with DM. As pancreatic islets present an important role in glucose homeostasis, we aim to study the role of physical exercise (chronic adaptations and acute responses) in pancreatic islets functionality in Wistar male rats. First, animals were di...

  1. Data on morphometric analysis of the pancreatic islets from C57BL/6 and BALB/c mice

    Directory of Open Access Journals (Sweden)

    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.

  2. Light scattering as an intrinsic indicator for pancreatic islet cell mass and secretion.

    Science.gov (United States)

    Ilegems, E; van Krieken, P P; Edlund, P K; Dicker, A; Alanentalo, T; Eriksson, M; Mandic, S; Ahlgren, U; Berggren, P-O

    2015-01-01

    The pancreatic islet of Langerhans is composed of endocrine cells producing and releasing hormones from secretory granules in response to various stimuli for maintenance of blood glucose homeostasis. In order to adapt to a variation in functional demands, these islets are capable of modulating their hormone secretion by increasing the number of endocrine cells as well as the functional response of individual cells. A failure in adaptive mechanisms will lead to inadequate blood glucose regulation and thereby to the development of diabetes. It is therefore necessary to develop tools for the assessment of both pancreatic islet mass and function, with the aim of understanding cellular regulatory mechanisms and factors guiding islet plasticity. Although most of the existing techniques rely on the use of artificial indicators, we present an imaging methodology based on intrinsic optical properties originating from mature insulin secretory granules within endocrine cells that reveals both pancreatic islet mass and function. We demonstrate the advantage of using this imaging strategy by monitoring in vivo scattering signal from pancreatic islets engrafted into the anterior chamber of the mouse eye, and how this versatile and noninvasive methodology permits the characterization of islet morphology and plasticity as well as hormone secretory status. PMID:26030284

  3. Beta-cell function in isolated human pancreatic islets in long-term tissue culture

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    1981-01-01

    Human pancreatic islets were isolated by collagenase treatment of pancreatic tissue obtained from 27 individuals aged 12 to 69 years. The islets were maintained free floating in tissue culture medium RPMI 1640 supplemented with calf or human serum. In two cases the insulin production was followed...... adult human pancreatic tissue and that their beta-cell function can be maintained for up to two years. The variation in insulin production rate could not be ascribed to age or sex and may reflect both physiological and methodological factors....... up to nearly two years. The insulin production rate of the individual islet preparations varied between 0.2 and 8 ng per islet per day. No significant correlation with donor age or sex was found. The glucose concentration in the medium influenced the insulin release in a dose dependent manner. The...

  4. Transport of ascorbic acid and dehydroascorbic acid by pancreatic islet cells from neonatal rats

    DEFF Research Database (Denmark)

    Zhou, A; Farver, O; Thorn, N A;

    1991-01-01

    Several amidated biologically active peptides such as pancreastatin, thyrotropin-releasing hormone, pancreatic polypeptide and amylin are produced in endocrine pancreatic tissue which contains the enzyme necessary for their final processing, i.e. peptidylglycine alpha-amidating mono-oxygenase (EC 1.......14.17.3). The enzyme needs ascorbic acid for activity as well as copper and molecular oxygen. The present work shows that pancreatic islet cells prepared from overnight cultures of isolated islets from 5-7-day-old rats accumulate 14C-labelled ascorbic acid by a Na(+)-dependent active transport mechanism which involves...

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

    OpenAIRE

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

    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 pan...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    independence. Islets were pooled from two donors with respectively one and five HLA mismatches. Insulin-positive islets were found throughout the right and left liver, and absent in the pancreas. Two- and three-dimensional analysis showed that islets lost their initial rounded and compact morphology, had...

  7. Effect of low temperature cultivation on insulin secretory of human pancreatic islets.

    Science.gov (United States)

    Nikolic, D M; Djordjevic, P B; Lackovic, V B; Stojiljkovic, V; Stanojevic, B

    2013-01-01

    The experiment compared the physiological function (insulin secretory capacity) and membrane integrity of human adult pancreatic islets incubated in culture at 37°C and 24°C. Pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated at 37°C and 24°C. Secretory capacity of the islets is determined by measuring of the stimulation index (SI) on the 1st, 3rd and 7th day of cultivation. Membrane integrity of the islets was determined by dithizone staining. Both groups of examined cultures show a slight increase in SI during the incubation. However islets incubated at 24°C show higher SI values than those incubated at 37°C on the 1st, 3rd and 7th day of incubation. And on the first day of incubation, this difference was statistically significant (p <0.05). Islets incubated at 37°C showed preservation of membrane integrity, the islets are regular spherical shape, while those incubated at 24°C lose such an organization. During the seven-day cultivation, islets incubated at a standard temperature of 37°C show less preserve physiological functions in relation to cultures incubated at 24°C, but islets incubated at 37°C show more regular morphological forms. PMID:23489685

  8. Pancreatic islet blood flow in conscious rats during hyperglycemia and hypoglycemia.

    Science.gov (United States)

    Iwase, M; Tashiro, K; Uchizono, Y; Goto, D; Yoshinari, M

    2001-06-01

    Anesthesia affects general hemodynamics and regulation of organ perfusion. We used colored microspheres to measure pancreatic islet blood flow in conscious rats at two time points, during either hyperglycemia or hypoglycemia. This method, using black and green microspheres, was validated by comparison with previous microsphere experiments and by lack of effect of a nonmetabolizable glucose analog, 3-O-methylglucose, on islet perfusion. Basal and glucose-stimulated islet blood flow levels were similar in pentobarbital sodium-anesthetized and conscious rats. However, the basal distribution of pancreatic blood flow was altered by anesthesia (fractional islet blood flow 5.8 +/- 0.4% in conscious rats, 7.9 +/- 0.8% in pentobarbital-anesthetized rats, P conscious rats, whereas islet blood flow remained unchanged and fractional islet blood flow was decreased (5.8 +/- 0.5% in the basal state, 4.2 +/- 0.4% during hypoglycemia, P < 0.001). Methylatropine pretreatment significantly increased islet blood flow during hypoglycemia by 181%. This result suggests that prevention of hypoglycemia-induced increase in islet perfusion may be mediated, at least in part, by a cholinergic, vagal muscarinic mechanism. PMID:11353660

  9. Physical exercise and pancreatic islets: acute and chronic actions on insulin secretion.

    Science.gov (United States)

    Almeida, Felipe N; Proença, André R G; Chimin, Patrícia; Marçal, Anderson C; Bessa-Lima, Fábio; Carvalho, Carla R O

    2012-01-01

    Diabetes mellitus (DM) is a great public health problem, which attacks part of the world population, being characterized by an imbalance in body glucose homeostasis. Physical exercise is pointed as a protective agent and is also recommended to people with DM. As pancreatic islets present an important role in glucose homeostasis, we aim to study the role of physical exercise (chronic adaptations and acute responses) in pancreatic islets functionality in Wistar male rats. First, animals were divided into two groups: sedentary (S) and aerobic trained (T). At the end of 8 weeks, half of them (S and T) were submitted to an acute exercise session (exercise until exhaustion), being subdivided as acute sedentary (AS) and acute trained (AT). After the experimental period, periepididymal, retroperitoneal and subcutaneous fat pads, blood, soleus muscle and pancreatic islets were collected and prepared for further analysis. From the pancreatic islets, total insulin content, insulin secretion stimulated by glucose, leucine, arginine and carbachol were analyzed. Our results pointed that body adiposity and glucose homeostasis improved with chronic physical exercise. In addition, total insulin content was reduced in group AT, insulin secretion stimulated by glucose was reduced in trained groups (T and AT) and insulin secretion stimulated by carbachol was increased in group AT. There were no significant differences in insulin secretion stimulated by arginine and leucine. We identified a possible modulating action on insulin secretion, probably related to the association of chronic adaptation with an acute response on cholinergic activity in pancreatic islets. PMID:22868676

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

    Directory of Open Access Journals (Sweden)

    Wanyu Chen

    Full Text Available 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

  11. Striated Muscle as Implantation Site for Transplanted Pancreatic Islets

    Science.gov (United States)

    Espes, Daniel; Eriksson, Olof; Lau, Joey; Carlsson, Per-Ola

    2011-01-01

    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. PMID:22174984

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

    International Nuclear Information System (INIS)

    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

  13. Microfluidic perfusion systems for secretion fingerprint analysis of pancreatic islets: applications, challenges and opportunities.

    Science.gov (United States)

    Castiello, F Rafael; Heileman, Khalil; Tabrizian, Maryam

    2016-02-01

    A secretome signature is a heterogeneous profile of secretions present in a single cell type. From the secretome signature a smaller panel of proteins, namely a secretion fingerprint, can be chosen to feasibly monitor specific cellular activity. Based on a thorough appraisal of the literature, this review explores the possibility of defining and using a secretion fingerprint to gauge the functionality of pancreatic islets of Langerhans. It covers the state of the art regarding microfluidic perfusion systems used in pancreatic islet research. Candidate analytical tools to be integrated within microfluidic perfusion systems for dynamic secretory fingerprint monitoring were identified. These analytical tools include patch clamp, amperometry/voltametry, impedance spectroscopy, field effect transistors and surface plasmon resonance. Coupled with these tools, microfluidic devices can ultimately find applications in determining islet quality for transplantation, islet regeneration and drug screening of therapeutic agents for the treatment of diabetes. PMID:26732665

  14. Light scattering as an intrinsic indicator for pancreatic islet cell mass and secretion

    OpenAIRE

    Ilegems, E.; van Krieken, P. P.; Edlund, P. K.; Dicker, A.; Alanentalo, T.; Eriksson, Maria; Mandic, S.; Ahlgren, Ulf; Berggren, P.-O.

    2015-01-01

    The pancreatic islet of Langerhans is composed of endocrine cells producing and releasing hormones from secretory granules in response to various stimuli for maintenance of blood glucose homeostasis. In order to adapt to a variation in functional demands, these islets are capable of modulating their hormone secretion by increasing the number of endocrine cells as well as the functional response of individual cells. A failure in adaptive mechanisms will lead to inadequate blood glucose regulat...

  15. Characterization of the mouse pancreatic islet proteome and comparative analysis with other mouse tissues

    Energy Technology Data Exchange (ETDEWEB)

    Petyuk, Vladislav A.; Qian, Weijun; Hinault, Charlotte; Gritsenko, Marina A.; Singhal, Mudita; Monroe, Matthew E.; Camp, David G.; Kulkarni, Rohit N.; Smith, Richard D.

    2008-08-01

    The pancreatic islets of Langerhans and insulin-producing beta cells in particular play a central role in the maintenance of glucose homeostasis and the islet dysfunction is associated with the pathogenesis of both type 1 and type 2 diabetes mellitus. To contribute to the understanding of the biology of the pancreatic islets we applied proteomic techniques based on liquid chromatography coupled with mass spectrometry. Here as an initial step we present the first comprehensive proteomic characterization of pancreas islets of the mouse, the commonly used animal model for diabetes research. Two-dimensional SCX LC/RP LC-MS/MS has been applied to characterize of the mouse islet proteome, resulting in the confident identification of 17,350 different tryptic peptides covering 2,612 proteins with at least two unique peptide identifications per protein. The dataset also allowed identification of a number of post-translational modifications including several modifications relevant to oxidative stress and phosphorylation. While many of the identified phosphorylation sites corroborates with previous known sites, the oxidative modifications observed on cysteinyl residues potentially reveal novel information related to the role of oxidation stress in islet functions. Comparative analysis of the islet proteome database with 15 available proteomic datasets from other mouse tissues and cells revealed a set of 68 proteins uniquely detected only in the pancreatic islets. Besides proteins with known functions, like islet secreted peptide hormones, this unique set contains a number of proteins with yet unknown functions. The resulting peptide and protein database will be available at ncrr.pnl.gov web site of the NCRR proteomic center (ncrr.pnl.gov).

  16. Hypothyroidism Affects Vascularization and Promotes Immune Cells Infiltration into Pancreatic Islets of Female Rabbits

    Science.gov (United States)

    Rodríguez-Castelán, Julia; Martínez-Gómez, Margarita; Castelán, Francisco; Cuevas, Estela

    2015-01-01

    Thyroidectomy induces pancreatic edema and immune cells infiltration similarly to that observed in pancreatitis. In spite of the controverted effects of hypothyroidism on serum glucose and insulin concentrations, the number and proliferation of Langerhans islet cells as well as the presence of extracellular matrix are affected depending on the islet size. In this study, we evaluated the effect of methimazole-induced hypothyroidism on the vascularization and immune cells infiltration into islets. A general observation of pancreas was also done. Twelve Chinchilla-breed female adult rabbits were divided into control (n = 6) and hypothyroid groups (n = 6, methimazole, 0.02% in drinking water for 30 days). After the treatment, rabbits were sacrificed and their pancreas was excised, histologically processed, and stained with Periodic Acid-Schiff (PAS) or Masson's Trichrome techniques. Islets were arbitrarily classified into large, medium, and small ones. The external and internal portions of each islet were also identified. Student-t-test and Mann-Whitney-U test or two-way ANOVAs were used to compare variables between groups. In comparison with control rabbits, hypothyroidism induced a strong infiltration of immune cells and a major presence of collagen and proteoglycans in the interlobular septa. Large islets showed a high vascularization and immune cells infiltration. The present results show that hypothyroidism induces pancreatitis and insulitis. PMID:26175757

  17. Effects of Fungal Pancreatic Enzymes on the Function of Islet Cells in Syrian Golden Hamsters

    Directory of Open Access Journals (Sweden)

    Fumiaki Nozawa

    2013-05-01

    Full Text Available Context Our previous studies showed that porcine pancreatic enzymes in Syrian golden hamsters with peripheral insulin resistance normalizes the plasma insulin level, reduces the size of enlarged islets and inhibits the increased DNA synthesis in the beta-cell of islets. Objective In order to exclude the possibility that these effects was attributed to some contaminants of this crude material, we tested the effect of purified fungal pancreatic enzyme (FPE that contains primarily amylase and lipase without (FPE and with addition of chymotrypsin (FPE+chy. Material and methods In a pilot study we tested the effect of different doses of FPE given in drinking water on insulin level, islet size and DNA synthesis of islet cells in hamsters with induced peripheral insulin resistance by a high fat diet. The most effective dose of FPE on these parameters was used in a long-term experiment with FPE and FPE+chy in hamsters fed a high-fat diet for 36 or 40 weeks. Results In the pilot study a dose of 2 g/kg body weight was found to be optimal for controlling the body weight, normalizing plasma insulin level, the size of islets, the DNA synthesis and the number of insulin cells in the islets. These data were produced in the long-term study, where steatorrhea was also inhibited. Addition of chymotrypsin had no effects on these parameters. Conclusion Pancreatic lipase and amylase appear to be responsible for the observed effects and offer a safe and effective natural product for the treatment of pancreatic diseases, including acute pancreatitis, chronic pancreatic, cystic fibrosis and any conditions associated with peripheral insulin resistance, including obesity and type 2 diabetes. The possible mechanism of the action is discussed.

  18. Cloning and functional expression of a human pancreatic islet glucose-transporter cDNA

    International Nuclear Information System (INIS)

    Previous studies have suggested that pancreatic islet glucose transport is mediated by a high-Km, 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

  19. The morphology of islets within the porcine donor pancreas determines the isolation result: successful isolation of pancreatic islets can now be achieved from young market pigs.

    Science.gov (United States)

    Krickhahn, Mareike; Bühler, Christoph; Meyer, Thomas; Thiede, Arnulf; Ulrichs, Karin

    2002-01-01

    Clinical islet allotransplantation has become an increasingly efficient "routine" therapy in recent years. Shortage of human donor organs leads to porcine pancreatic islets as a potential source for islet xenotransplantation. Yet it is still very difficult to isolate sufficient numbers of intact porcine islets, particularly from young market pigs. In the following study islets were successfully isolated from retired breeders [4806 +/- 720 islet equivalents per gram organ (IEQ/g); n = 25; 2-3 years old; RB] and also from young hybrid pigs [2868 +/- 260 IEQ/g; n = 65; 4-6 months old; HY] using LiberasePI and a modified version of Ricordi's digestion-filtration technique. As expected, isolations from RB showed significantly better results (p organs from RB (80%) contained mainly large islets (diameter > 200 microm), in contrast to only 35% of all pancreases from HY. Remarkably, the islet size in situ, regardless whether detected in RB or HY, strongly determined the isolation result. A donor organ with predominantly large islets resulted in significantly higher numbers of IEQs compared with a donor organ with predominantly small islets [RB(Large Islets): 5680 +/- 3,318 IEQ/g (n= 20); RB(Small Islets): 1353 +/- 427 IEQ/g (n = 5); p organ prior to the isolation process. Under these conditions highly successful isolations can reliably be performed even from young market pigs.

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

    Directory of Open Access Journals (Sweden)

    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. Dipeptidyl peptidase IV inhibitor MK-0626 attenuates pancreatic islet injury in tacrolimus-induced diabetic rats.

    Directory of Open Access Journals (Sweden)

    Long Jin

    Full Text Available Tacrolimus (TAC-induced pancreatic islet injury is one of the important causes of new-onset diabetes in transplant recipients. This study was performed to evaluate whether a dipeptidyl peptidase IV (DPP IV inhibitor is effective in improving TAC-induced diabetes mellitus by reducing pancreatic islet injury.Rats were treated with TAC (1.5 mg/kg, subcutaneously and the DPP IV inhibitor MK-0626 (10 or 20 mg/kg, oral gavage for 4 weeks. The effect of MK-0626 on TAC-induced diabetes was evaluated by assessing pancreatic islet function, histopathology. TAC-induced incretin dysfunction was also examined based on active glucagon-like peptide-1 (GLP-1 levels in the serum after glucose loading. The protective effect of MK-0626 was evaluated by measuring markers of oxidative stress, oxidative resistance, and apoptosis. To determine whether enhanced GLP-1 signaling is associated with these protective effects, we measured the expression of the GLP-1 receptor (GLP-1R and the effect of the GLP-1 analog exendin-4 on cell viability and oxidative stress in isolated islets.MK-0626 treatment attenuated TAC-induced pancreatic islet dysfunction and islet morphology. TAC treatment led to a defect in active GLP-1 secretion; however, MK-0626 reversed these effects. TAC treatment increased the level of 8-hydroxy-2'-deoxyguanosine (8-OHdG, the number of apoptotic death, and the level of active caspase-3, and decreased the level of manganese superoxide dismutase and heme oxygenase-1; MK-0626 treatment reversed these changes. MK-0626 treatment restored the expression of GLP-1R, and direct administration of exendin-4 to isolated islets reduced TAC-induced cell death and 8-OHdG expression.The DPP IV inhibitor MK-0626 was an effective antidiabetic agent that exerted antioxidative and antiapoptotic effects via enhanced GLP-1 signaling in TAC-induced diabetics.

  2. B7-H4 as a protective shield for pancreatic islet beta cells

    Institute of Scientific and Technical Information of China (English)

    Annika; C; Sun; Dawei; Ou; Dan; S; Luciani; Garth; L; Warnock

    2014-01-01

    Auto- and alloreactive T cells are major culprits that damage β-cells in type 1 diabetes(T1D) and islet transplantation. Current immunosuppressive drugs can alleviate immune-mediated attacks on islets. T cell co-stimulation blockade has shown great promise in autoimmunity and transplantation as it solely targets activated T cells, and therefore avoids toxicity of current immunosuppressive drugs. An attractive approach is offered by the newly-identified negative T cell cosignaling molecule B7-H4 which is expressed in normal human islets, and its expression co-localizes with insulin. A concomitant decrease in B7-H4/insulin colocalization is observed in human type 1 diabetic islets. B7-H4 may play protective roles in the pancreatic islets, preserving their function and survival. In this review we outline the protective effect of B7-H4 in the contexts of T1 D, islet cell transplantation, and potentially type 2 diabetes. Current evidence offers encouraging data regarding the role of B7-H4 in reversal of autoimmune diabetes and donor-specific islet allograft tolerance. Additionally, unique expression of B7-H4 may serve as a potential biomarker for the development of T1 D. Futurestudies should continue to focus on the islet-specific effects of B7-H4 with emphasis on mechanistic pathways in order to promote B7-H4 as a potential therapy and cure for T1 D.

  3. Altered Expression of Somatostatin Receptors in Pancreatic Islets from NOD Mice Cultured at Different Glucose Concentrations In Vitro and in Islets Transplanted to Diabetic NOD Mice In Vivo

    Directory of Open Access Journals (Sweden)

    Eva Ludvigsen

    2011-01-01

    Full Text Available Somatostatin acts via five receptors (sst1-5. We investigated if the changes in pancreatic islet sst expression in diabetic NOD mice compared to normoglycemic mice are a consequence of hyperglycemia or the ongoing immune reaction in the pancreas. Pancreatic islets were isolated from NOD mice precultured for 5 days and further cultured for 3 days at high or low glucose before examined. Islets were also isolated from NOD mice and transplanted to normal or diabetic mice in a number not sufficient to cure hyperglycemia. After three days, the transplants were removed and stained for sst1-5 and islet hormones. Overall, changes in sst islet cell expression were more common in islets cultured in high glucose concentration in vitro as compared to the islet transplantation in vivo to diabetic mice. The beta and PP cells exhibited more frequent changes in sst expression, while the alpha and delta cells were relatively unaffected by the high glucose condition. Our findings suggest that the glucose level may alter sst expressed in islets cells; however, immune mechanisms may counteract such changes in islet sst expression.

  4. Antioxidant activity of chito-oligosaccharides on pancreatic islet cells in streptozotocin-induced diabetes in rats

    Institute of Scientific and Technical Information of China (English)

    Wen-Peng Yuan; Bing Liu; Chang-Heng Liu; Xiao-Jun Wang; Mian-Song Zhang; Xiu-Mei Meng; Xue-Kui Xia

    2009-01-01

    AIM: To investigate the antioxidant activity of chitooligosaccharides (COSs) on pancreatic islet cells in diabetic rats induced by streptozotocin.METHODS: The antioxidant effect of COSs on pancreatic islet cells was detected under optical microscopy and with colorimetric assay and gel electrophoresis. The activities of glutathione peroxidase and superoxide dismutase, total antioxidant capacity, and content of malondialdehyde in serum and tissue slices of pancreas were examined after 60 d to determine the effect of COSs in streptozotocin-induced diabetes in rats.RESULTS: COSs can prohibit the apoptosis of pancreatic islet cells. All concentrations of COSs can improve the capability of total antioxidant capacity and activity of superoxide dismutase and decrease the content of malondialdehyde drastically. Morphological investigation in the pancreas showed that COSs have resulted in the reduction of islets, loss of pancreatic cells, and nuclear pyknosis of pancreatic cells.CONCLUSION: COSs possess various biological activities and can be used in the treatment of diabetes mellitus.

  5. Assessment of benzene induced oxidative impairment in rat isolated pancreatic islets and effect on insulin secretion.

    Science.gov (United States)

    Bahadar, Haji; Maqbool, Faheem; Mostafalou, Sara; Baeeri, Maryam; Rahimifard, Mahban; Navaei-Nigjeh, Mona; Abdollahi, Mohammad

    2015-05-01

    Benzene (C6H6) is an organic compound used in petrochemicals and numerous other industries. It is abundantly released to our environment as a chemical pollutant causing widespread human exposure. This study mainly focused on benzene induced toxicity on rat pancreatic islets with respect to oxidative damage, insulin secretion and glucokinase (GK) activity. Benzene was dissolved in corn oil and administered orally at doses 200, 400 and 800mg/kg/day, for 4 weeks. In rats, benzene significantly raised the concentration of plasma insulin. Also the effect of benzene on the release of glucose-induced insulin was pronounced in isolated islets. Benzene caused oxidative DNA damage and lipid peroxidation, and also reduced the cell viability and total thiols groups, in the islets of exposed rats. In conclusion, the current study revealed that pancreatic glucose metabolism is susceptible to benzene toxicity and the resultant oxidative stress could lead to functional abnormalities in the pancreas. PMID:25935538

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

    DEFF Research Database (Denmark)

    Dalgaard, Louise Torp

    2012-01-01

    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...

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

    International Nuclear Information System (INIS)

    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

  8. 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 oscillations...

  9. Pig-to-Nonhuman Primates Pancreatic Islet Xenotransplantation: An Overview

    OpenAIRE

    Marigliano, Marco; Bertera, Suzanne; Grupillo, Maria; Trucco, Massimo; Bottino, Rita

    2011-01-01

    The therapy of type 1 diabetes is an open challenging problem. The restoration of normoglycemia and insulin independence in immunosuppressed type 1 diabetic recipients of islet allotransplantation has shown the potential of a cell-based diabetes therapy. Even if successful, this approach poses a problem of scarce tissue supply. Xenotransplantation can be the answer to this limited donor availability and, among possible candidate tissues for xenotransplantation, porcine islets are the closest ...

  10. Adaptation of pancreatic islet cyto-architecture during development

    Science.gov (United States)

    Striegel, Deborah A.; Hara, Manami; Periwal, Vipul

    2016-04-01

    Plasma glucose in mammals is regulated by hormones secreted by the islets of Langerhans embedded in the exocrine pancreas. Islets consist of endocrine cells, primarily α, β, and δ cells, which secrete glucagon, insulin, and somatostatin, respectively. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Varying demands and available nutrients during development produce changes in the local connectivity of β cells in an islet. We showed in earlier work that graph theory provides a framework for the quantification of the seemingly stochastic cyto-architecture of β cells in an islet. To quantify the dynamics of endocrine connectivity during development requires a framework for characterizing changes in the probability distribution on the space of possible graphs, essentially a Fokker-Planck formalism on graphs. With large-scale imaging data for hundreds of thousands of islets containing millions of cells from human specimens, we show that this dynamics can be determined quantitatively. Requiring that rearrangement and cell addition processes match the observed dynamic developmental changes in quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that there is a transient shift in preferred connectivity for β cells between 1–35 weeks and 12–24 months.

  11. Adaptation of pancreatic islet cyto-architecture during development.

    Science.gov (United States)

    Striegel, Deborah A; Hara, Manami; Periwal, Vipul

    2016-01-01

    Plasma glucose in mammals is regulated by hormones secreted by the islets of Langerhans embedded in the exocrine pancreas. Islets consist of endocrine cells, primarily α, β, and δ cells, which secrete glucagon, insulin, and somatostatin, respectively. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Varying demands and available nutrients during development produce changes in the local connectivity of β cells in an islet. We showed in earlier work that graph theory provides a framework for the quantification of the seemingly stochastic cyto-architecture of β cells in an islet. To quantify the dynamics of endocrine connectivity during development requires a framework for characterizing changes in the probability distribution on the space of possible graphs, essentially a Fokker-Planck formalism on graphs. With large-scale imaging data for hundreds of thousands of islets containing millions of cells from human specimens, we show that this dynamics can be determined quantitatively. Requiring that rearrangement and cell addition processes match the observed dynamic developmental changes in quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that there is a transient shift in preferred connectivity for β cells between 1-35 weeks and 12-24 months. PMID:27063927

  12. Glycolytic and Mitochondrial Metabolism in Pancreatic Islets from MSG-Treated Obese Rats Subjected to Swimming Training

    Directory of Open Access Journals (Sweden)

    Nayara de Carvalho Leite

    2013-02-01

    Full Text Available Backgrounds/Aims: Obese rats obtained by neonatal monosodium glutamate (MSG administration present insulin hypersecretion. The metabolic mechanism by which glucose catabolism is coupled to insulin secretion in the pancreatic β-cells from MSG-treated rats is understood. The purpose of this study was to evaluate glucose metabolism in pancreatic islets from MSG-treated rats subjected to swimming training. Methods: MSG-treated and control (CON rats swam for 30 minutes (3 times/week over a period of 10 weeks. Pancreatic islets were isolated and incubated with glucose in the presence of glycolytic or mitochondrial inhibitors. Results: Swimming training attenuated fat pad accumulation, avoiding changes in the plasma levels of lipids, glucose and insulin in MSG-treated rats. Adipocyte and islet hypertrophy observed in MSG-treated rats were attenuated by exercise. Pancreatic islets from MSG-treated obese rats also showed insulin hypersecretion, greater glucose transporter 2 (GLUT2 expression, increased glycolytic flux and reduced mitochondrial complex III activity. Conclusion: Swimming training attenuated islet hypertrophy and normalised GLUT2 expression, contributing to a reduction in the glucose responsiveness of pancreatic islets from MSG-treated rats without altering glycolytic flux. However, physical training increased the activity of mitochondrial complex III in pancreatic islets from MSG-treated rats without a subsequent increase in glucose-induced insulin secretion.

  13. Ultrastructural Islet Study of Early Fibrosis in the Ren2 Rat Model of Hypertension. Emerging Role of the Islet Pancreatic Pericyte-Stellate Cell

    Directory of Open Access Journals (Sweden)

    Melvin R Hayden

    2007-11-01

    Full Text Available Context Type 2 diabetes mellitus is a multifactorial disease with polygenic and environmental stressors resulting in multiple metabolic toxicities and islet oxidative stress. We have integrated the role of the islet reninangiotensin system (RAS in the pathogenesis of early islet fibrosis utilizing the transgenic (mRen227 rodent model of hypertension and tissue RAS overexpression. Objective The Ren2 pancreatic islet tissue was evaluated with transmission electron microscopy to study both early cellular and extracellular matrix remodeling. Animals Four 9- to 10-week-old male Ren2 untreated models and four Sprague Dawley sex and age matched controls were used. Design Ultrastructural study to compare pancreatic islet tissue. Main outcome measures Only qualitative and observational transmission electron microscopy findings are reported. Results Major remodeling differences in the Ren2 model were found to be located within the islet exocrine interface, including deposition of early fibrillar-banded collagen (fibrosis and cellular remodeling of the pericyte suggesting proliferation, migration, hypertrophy and activation as compared to the Sprague Dawley controls. Conclusion This study points to the possibility of the pericyte cell being one of many contributors to the fibrogenic pool of cells important for peri-islet fibrosis as a result of excess angiotensin II at the local tissue level in the Ren2 model. These findings suggest that the pericyte may be capable of differentiating into the pancreatic stellate cell. This islet ultrastructure study supports the notion that pericyte cells could be the link between islet vascular oxidative stress and peri-islet fibrosis. Pericyte-endothelialpancreatic stellate cell associations and morphology are discussed.

  14. Immunohistochemical localization of glucagon and pancreatic polypeptide on rat endocrine pancreas: coexistence in rat islet cells

    Directory of Open Access Journals (Sweden)

    YH Huang

    2009-08-01

    Full Text Available We used immunofluorescence double staining method to investigate the cellular localization of glucagon and pancreatic polypeptide (PP in rat pancreatic islets. The results showed that both A-cells (glucagon-secreting cells and PP-cells (PPsecreting cells were located in the periphery of the islets. However, A-cells and PP-cells had a different regional distribution. Most of A-cells were located in the splenic lobe but a few of them were in the duodenal lobe of the pancreas. In contrast, the majority of PP-cells were found in the duodenal lobe and a few of them were in the splenic lobe of the pancreas. Furthermore, we found that 67.74% A-cells had PP immunoreactivity, 70.92% PP-cells contained glucagon immunoreactivity with immunofluorescence double staining. Our data support the concept of a common precursor stem cell for pancreatic hormone-producing cells.

  15. Culturing pancreatic islets in microfluidic flow enhances morphology of the associated endothelial cells.

    Directory of Open Access Journals (Sweden)

    Krishana S Sankar

    Full Text Available Pancreatic islets are heavily vascularized in vivo with each insulin secreting beta-cell associated with at least one endothelial cell (EC. This structure is maintained immediately post-isolation; however, in culture the ECs slowly deteriorate, losing density and branched morphology. We postulate that this deterioration occurs in the absence of blood flow due to limited diffusion of media inside the tissue. To improve exchange of media inside the tissue, we created a microfluidic device to culture islets in a range of flow-rates. Culturing the islets from C57BL6 mice in this device with media flowing between 1 and 7 ml/24 hr resulted in twice the EC-density and -connected length compared to classically cultured islets. Media containing fluorescent dextran reached the center of islets in the device in a flow-rate-dependant manner consistent with improved penetration. We also observed deterioration of EC morphology using serum free media that was rescued by addition of bovine serum albumin, a known anti-apoptotic signal with limited diffusion in tissue. We further examined the effect of flow on beta-cells showing dampened glucose-stimulated Ca(2+-response from cells at the periphery of the islet where fluid shear-stress is greatest. However, we observed normal two-photon NAD(PH response and insulin secretion from the remainder of the islet. These data reveal the deterioration of islet EC-morphology is in part due to restricted diffusion of serum albumin within the tissue. These data further reveal microfluidic devices as unique platforms to optimize islet culture by introducing intercellular flow to overcome the restricted diffusion of media components.

  16. Profile of blood glucose and ultrastucture of beta cells pancreatic islet in alloxan compound induced rats

    Directory of Open Access Journals (Sweden)

    I Nyoman Suarsana

    2010-06-01

    Full Text Available Diabetes is marked by elevated levels of blood glucose, and progressive changes of the structure of pancreatic islet histopathology. The objective of this research was to analyse the glucose level and histophatological feature in pancreatic islet in alloxan compound induced rats. A total of ten male Spraque Dawley rats of 2 months old were used in this study. The rats were divided into two groups: (1 negative control group (K-, and (2 positif induced alloxan group (diabetic group =DM. The rats were induced by a single dose intraperitonial injection of alloxan compound 120 mg/kg of body weight. The treatment was conducted for 28 days. Blood glucose levels of rats were analysed at 0, 4, 7, 14, 21, and 28 days following treatment. At the end of the experiment, rats were sacrificed by cervical dislocation. Pancreas was collected for analysis of histopathological study by Immunohistochemical technique, and ultrastructural study using transmission electron microscope (TEM. The result showed that Langerhans islet of diabetic rat (rat of DM group showed a marked reduction of size, number of Langerhans islet of diabetic rat decrease, and characterized by hyperglycemic condition. By using TEM, beta cells of DM group showed the rupture of mitochondrial membrane, the lost of cisternal structure of inner membrane of mitocondria, reduction of insulin secretory granules, linkage between cells acinar with free Langerhans islet, and the caryopicnotic of nucleus.

  17. 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...... 1.4-4.5) before and 31.5 U/mL (range 18.6-51.8) immediately after an intravenous injection of 1000 U/kg L-asparaginase. Glucose-induced insulin release from pancreatic islets of rat and man was measured after 3 and 7 days of culture in media with or without clinically relevant concentrations...... of Escherichia coli L-asparaginase (0.01-100 U/mL). After culture, the remaining insulin, glucagon, and DNA in the islets were determined. After 7 days of culture of adult rat or human islets, both the accumulation of insulin in the medium and the content of insulin and glucagon in the islets were significantly...

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

    Energy Technology Data Exchange (ETDEWEB)

    Antoine, M.H.; Hermann, M.; Herchuelz, A.; Lebrun, P. (Laboratory of Pharmacology, Brussels Free University School of Medicine (Belgium))

    1991-07-01

    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.

  19. Assessment of Toxicological Perturbations and Variants of Pancreatic Islet Development in the Zebrafish Model

    Directory of Open Access Journals (Sweden)

    Karilyn E. Sant

    2016-09-01

    Full Text Available The pancreatic islets, largely comprised of insulin-producing beta cells, play a critical role in endocrine signaling and glucose homeostasis. Because they have low levels of antioxidant defenses and a high perfusion rate, the endocrine islets may be a highly susceptible target tissue of chemical exposures. However, this endpoint, as well as the integrity of the surrounding exocrine pancreas, is often overlooked in studies of developmental toxicology. Disruption of development by toxicants can alter cell fate and migration, resulting in structural alterations that are difficult to detect in mammalian embryo systems, but that are easily observed in the zebrafish embryo model (Danio rerio. Using endogenously expressed fluorescent protein markers for developing zebrafish beta cells and exocrine pancreas tissue, we documented differences in islet area and incidence rates of islet morphological variants in zebrafish embryos between 48 and 96 h post fertilization (hpf, raised under control conditions commonly used in embryotoxicity assays. We identified critical windows for chemical exposures during which increased incidences of endocrine pancreas abnormalities were observed following exposure to cyclopamine (2–12 hpf, Mono-2-ethylhexyl phthalate (MEHP (3–48 hpf, and Perfluorooctanesulfonic acid (PFOS (3–48 hpf. Both islet area and length of the exocrine pancreas were sensitive to oxidative stress from exposure to the oxidant tert-butyl hydroperoxide during a highly proliferative critical window (72 hpf. Finally, pancreatic dysmorphogenesis following developmental exposures is discussed with respect to human disease.

  20. Antidiabetic effects of chitooligosaccharides on pancreatic islet cells in streptozotocin-induced diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Bing Liu; Wan-Shun Liu; Bao-Qin Han; Yu-Ying Sun

    2007-01-01

    AIM: To investigate the effect of chitooligosaccharides on proliferation of pancreatic islet cells, release of insulin and 2 h plasma glucose in streptozotocin-induced diabetic rats.METHODS: In vitro, the effect of chitooligosaccharides on proliferation of pancreatic islet cells and release of insulin was detected with optical microscopy, colorimetric assay, and radioimmunoassay respectively. In vivo, the general clinical symptoms, 2 h plasma glucose, urine glucose, oral glucose tolerance were examined after sixty days of feeding study to determine the effect of chitooligosaccharides in streptozotocin-induced diabetic rats.RESULTS: Chitooligosaccharides could effectively accelerate the proliferation of pancreatic islet cells. Chitooligosaccharides (100 mg/L) had direct and prominent effect on pancreastic β cells and insulin release from islet cells. All concentrations of chitooligosaccharides could improve the general clinical symptoms of diabetic rats, decrease the 2 h plasma glucose and urine glucose, and normalize the disorders of glucose tolerance.CONCLUSION: Chitooligosaccharides possess various biological activities and can be used in the treatment of diabetes mellitus.

  1. 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.

  2. 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. PMID:25273481

  3. Intracerebral xenotransplantation of semipermeable membrane- encapsuled pancreatic islets

    Institute of Scientific and Technical Information of China (English)

    Zhao-Liang Xin; Song-Lin Ge; Xiao-Kang Wu; Yan-Jie Jia; Han-Tao Hu

    2005-01-01

    AIM: To identify the decreasing effect of xenotransplantion in combination with privileged sites on rejection and death of biological semipermeable membrane-(BSM) encapsulated implanted islets.METHODS: After the BSM experiment in vitro, BSMencapsulated SD rat's islet-like cell clusters (ICCs) were xenotransplanted into normal dog's brain. Morphological changes were observed under light and transmission electron microscope. The islets and apoptosis of implanted B cells were identified by insulin-TUNEL double staining.RESULTS: The BSM used in our study had a favorable permeability, some degree of rigidity, lighter foreign body reaction and toxicity. The grafts consisted of epithelioid cells and loose connective tissue. Severe infiltration of inflammatory cells was not observed. The implanted ICCs were identified 2 mo later and showed typical apoptosis.CONCLUSION: BSM xenotransplantation in combination with the privileged site can inhibit the rejection of implanted heterogeneous ICCs, and death of implanted heterogeneous B cells is associated with apoptosis.

  4. Establishing a human pancreatic stem cell line and transplanting induced pancreatic islets to reverse experimental diabetes in rats

    Institute of Scientific and Technical Information of China (English)

    XIAO Mei; DOU ZhongYing; AN LiLong; YANG XueYi; GE Xin; QIAO Hai; ZHAO Ting; MA XiaoFei; FAN JingZhua; ZHU MengYang

    2008-01-01

    The major obstacle in using pancreatic islet transplantation to cure type Ⅰ and some type Ⅱ diabetes is the shortage of the donors. One of ways to overcome such obstacle is to isolate and clone pancreatic stem cells as "seed cells" and induce their differentiation into functional islets as an abundant trans-plantation source. In this study, a monoclonal human pancreatic stem cell (mhPSC) line was obtained from abortive fetal pancreatic tissues. Pancreatic tissues were taken from abortive fetus by sterile procedures, and digested into single cells and cell clusters with 0.1% type Ⅳ collagenase. Cultured in modified glucose-low DMEM with 10% fetal bovine serum (FBS), these single cells and cell clusters adhered to culture dishes, and then primary epidermal-like pancreatic stem ceils started to clone. After digesting with 0.25% trypsin and 0.04% EDTA, fibroblasts and other cells were gradually eliminated and epithelioid pancreatic stem cells were gradually purified during generations. Using clone-ring selection, the mhPSCs were obtained. After addition of 10 ng/mL epidermal growth factor (EGF) in cell culture medium, the mhPSCs quickly grew and formed a gravelstone-like monolayer. Continuously proliferated, a mhPSC line, which was derived from a male abortive fetus of 4 months old, has been passed through 50 generations. More than 1×109 mhPSCs were cryo-preserved in liquid nitrogen. Karyotype analysis showed that the chromosome set of the mhPSC line was normal diploid. Immunocytochemistry results demonstrated that the mhPSC line was positive for the pdxl, glucagon, nestin and CK19, and negative for the insulin, CD34, CD44 and CD45 protein expression. RT-PCR revealed further that the mhPSCs expressed transcription factors of the pdx1, glucagon, nestin and CK19. Also, in vitro induced with β-mercaptoethanol, the mhPSCs differentiated into nerve cells that expressed the NF protein. Induced with nicotinamide, the mhPSCs differentiated into functional islet

  5. Establishing a human pancreatic stem cell line and transplanting induced pancreatic islets to reverse experimental diabetes in rats

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The major obstacle in using pancreatic islet transplantation to cure type I and some type II diabetes is the shortage of the donors. One of ways to overcome such obstacle is to isolate and clone pancreatic stem cells as "seed cells" and induce their differentiation into functional islets as an abundant trans-plantation source. In this study, a monoclonal human pancreatic stem cell (mhPSC) line was obtained from abortive fetal pancreatic tissues. Pancreatic tissues were taken from abortive fetus by sterile procedures, and digested into single cells and cell clusters with 0.1% type IV collagenase. Cultured in modified glucose-low DMEM with 10% fetal bovine serum (FBS), these single cells and cell clusters adhered to culture dishes, and then primary epidermal-like pancreatic stem cells started to clone. After digesting with 0.25% trypsin and 0.04% EDTA, fibroblasts and other cells were gradually eliminated and epithelioid pancreatic stem cells were gradually purified during generations. Using clone-ring selection, the mhPSCs were obtained. After addition of 10 ng/mL epidermal growth factor (EGF) in cell culture medium, the mhPSCs quickly grew and formed a gravelstone-like monolayer. Continuously proliferated, a mhPSC line, which was derived from a male abortive fetus of 4 months old, has been passed through 50 generations. More than 1×109 mhPSCs were cryo-preserved in liquid nitrogen. Karyotype analysis showed that the chromosome set of the mhPSC line was normal diploid. Immunocytochemistry results demonstrated that the mhPSC line was positive for the pdx1, glucagon, nestin and CK19, and negative for the insulin, CD34, CD44 and CD45 protein expression. RT-PCR revealed further that the mhPSCs expressed transcription factors of the pdx1, glucagon, nestin and CK19. Also, in vitro induced with β-mercaptoethanol, the mhPSCs differentiated into nerve cells that expressed the NF protein. Induced with nicotinamide, the mhPSCs differentiated into functional islet

  6. Regulation of PDK mRNA by high fatty acid and glucose in pancreatic islets.

    Science.gov (United States)

    Xu, Jianxiang; Han, Junying; Epstein, Paul N; Liu, Ye Q

    2006-06-01

    Pyruvate dehydrogenase (PDH) converts pyruvate to acetyl-CoA, links glycolysis to the Krebs cycle, and plays an important role in glucose metabolism and insulin secretion in pancreatic beta cells. In beta cells from obese and Type 2 diabetic animals, PDH activity is significantly reduced. PDH is negatively regulated by multiple pyruvate dehydrogenase kinase (PDK) isotypes (PDK subtypes 1-4). However, we do not know whether fatty acids or high glucose modulate PDKs in islets. To test this we determined PDH and PDK activities and PDK gene and protein expression in C57BL/6 mouse islets. Both high palmitate and high glucose reduced active PDH activity and increased PDK activity. The gene and protein for PDK3 were not expressed in islets. Palmitate up-regulated mRNA expression of PDK1 (2.9-fold), PDK2 (1.9-fold), and PDK4 (3.1-fold). High glucose increased PDK1 (1.8-fold) and PDK2 (2.7-fold) mRNA expression but reduced PDK4 mRNA expression by 40 percent in cultured islets. Changed PDK expression was confirmed by Western blotting. These results demonstrate that in islet cells both fat and glucose regulate PDK gene and protein expression and indicate that hyperglycemia and hyperlipidemia contribute to the decline in diabetic islet PDH activity by increasing mRNA and protein expression of PDK. PMID:16631612

  7. Effects of thioacetamide on pancreatic islet B-cell function

    NARCIS (Netherlands)

    Malaisse, WJ; Lebrun, P; Sener, A; Wolters, GHJ; Ravazzola, M

    2004-01-01

    Thioacetamide (0.01-1.3 mM) fails to exert any significant immediate effect upon insulin release from rat isolated islets. However, when administered (4 mumol/g body wt) intraperitoneally 24 h before sacrifice, it reduced food intake and body weight and affected the secretory response of isolated is

  8. Phase transitions in the multi-cellular regulatory behavior of pancreatic islet excitability.

    Science.gov (United States)

    Hraha, Thomas H; Westacott, Matthew J; Pozzoli, Marina; Notary, Aleena M; McClatchey, P Mason; Benninger, Richard K P

    2014-09-01

    The pancreatic islets of Langerhans are multicellular micro-organs integral to maintaining glucose homeostasis through secretion of the hormone insulin. β-cells within the islet exist as a highly coupled electrical network which coordinates electrical activity and insulin release at high glucose, but leads to global suppression at basal glucose. Despite its importance, how network dynamics generate this emergent binary on/off behavior remains to be elucidated. Previous work has suggested that a small threshold of quiescent cells is able to suppress the entire network. By modeling the islet as a Boolean network, we predicted a phase-transition between globally active and inactive states would emerge near this threshold number of cells, indicative of critical behavior. This was tested using islets with an inducible-expression mutation which renders defined numbers of cells electrically inactive, together with pharmacological modulation of electrical activity. This was combined with real-time imaging of intracellular free-calcium activity [Ca2+]i and measurement of physiological parameters in mice. As the number of inexcitable cells was increased beyond ∼15%, a phase-transition in islet activity occurred, switching from globally active wild-type behavior to global quiescence. This phase-transition was also seen in insulin secretion and blood glucose, indicating physiological impact. This behavior was reproduced in a multicellular dynamical model suggesting critical behavior in the islet may obey general properties of coupled heterogeneous networks. This study represents the first detailed explanation for how the islet facilitates inhibitory activity in spite of a heterogeneous cell population, as well as the role this plays in diabetes and its reversal. We further explain how islets utilize this critical behavior to leverage cellular heterogeneity and coordinate a robust insulin response with high dynamic range. These findings also give new insight into emergent

  9. Phase transitions in the multi-cellular regulatory behavior of pancreatic islet excitability.

    Directory of Open Access Journals (Sweden)

    Thomas H Hraha

    2014-09-01

    Full Text Available The pancreatic islets of Langerhans are multicellular micro-organs integral to maintaining glucose homeostasis through secretion of the hormone insulin. β-cells within the islet exist as a highly coupled electrical network which coordinates electrical activity and insulin release at high glucose, but leads to global suppression at basal glucose. Despite its importance, how network dynamics generate this emergent binary on/off behavior remains to be elucidated. Previous work has suggested that a small threshold of quiescent cells is able to suppress the entire network. By modeling the islet as a Boolean network, we predicted a phase-transition between globally active and inactive states would emerge near this threshold number of cells, indicative of critical behavior. This was tested using islets with an inducible-expression mutation which renders defined numbers of cells electrically inactive, together with pharmacological modulation of electrical activity. This was combined with real-time imaging of intracellular free-calcium activity [Ca2+]i and measurement of physiological parameters in mice. As the number of inexcitable cells was increased beyond ∼15%, a phase-transition in islet activity occurred, switching from globally active wild-type behavior to global quiescence. This phase-transition was also seen in insulin secretion and blood glucose, indicating physiological impact. This behavior was reproduced in a multicellular dynamical model suggesting critical behavior in the islet may obey general properties of coupled heterogeneous networks. This study represents the first detailed explanation for how the islet facilitates inhibitory activity in spite of a heterogeneous cell population, as well as the role this plays in diabetes and its reversal. We further explain how islets utilize this critical behavior to leverage cellular heterogeneity and coordinate a robust insulin response with high dynamic range. These findings also give new

  10. Dipeptidyl peptidase IV is sorted to the secretory granules in pancreatic islet A-cells

    DEFF Research Database (Denmark)

    Poulsen, Mona Dam; Hansen, Gert Helge; Dabelsteen, Erik;

    1993-01-01

    labeling using a monoclonal glucagon antibody as the second primary antibody. These results show that DP IV is sorted to secretory granules in the pig pancreatic islet A-cells. Furthermore, this secretory granule enzyme, as opposed to intestinal brush border DP IV, is suggested to be a soluble protein......Dipeptidyl peptidase IV (DP IV:EC 3.4.14.5) was localized in endocrine cells of pig pancreas by immunohistochemical and enzyme histochemical methods. Immunolight microscopy with both monoclonal and polyclonal antibodies demonstrated DP IV immunoreactivity in cells located in the peripheral part...... of the islets of Langerhans. The antigen is enzymatically active, as shown by enzyme histochemical analysis with a synthetic DP IV substrate. By immunoelectron microscopy (immunogold labeling), the labeling of DP IV in the islets was associated with the secretory granules of the A-cells, as identified by double...

  11. Differentiation of mesenchymal stem cells derived from pancreatic islets and bone marrow into islet-like cell phenotype.

    Directory of Open Access Journals (Sweden)

    Cristina Zanini

    Full Text Available BACKGROUND: Regarding regenerative medicine for diabetes, accessible sources of Mesenchymal Stem Cells (MSCs for induction of insular beta cell differentiation may be as important as mastering the differentiation process itself. METHODOLOGY/PRINCIPAL FINDINGS: In the present work, stem cells from pancreatic islets (human islet-mesenchymal stem cells, HI-MSCs and from human bone marrow (bone marrow mesenchymal stem cells, BM-MSCs were cultured in custom-made serum-free medium, using suitable conditions in order to induce differentiation into Islet-like Cells (ILCs. HI-MSCs and BM-MSCs were positive for the MSC markers CD105, CD73, CD90, CD29. Following this induction, HI-MSC and BM-MSC formed evident islet-like structures in the culture flasks. To investigate functional modifications after induction to ILCs, ultrastructural analysis and immunofluorescence were performed. PDX1 (pancreatic duodenal homeobox gene-1, insulin, C peptide and Glut-2 were detected in HI-ILCs whereas BM-ILCs only expressed Glut-2 and insulin. Insulin was also detected in the culture medium following glucose stimulation, confirming an initial differentiation that resulted in glucose-sensitive endocrine secretion. In order to identify proteins that were modified following differentiation from basal MSC (HI-MSCs and BM-MSCs to their HI-ILCs and BM-ILCs counterparts, proteomic analysis was performed. Three new proteins (APOA1, ATL2 and SODM were present in both ILC types, while other detected proteins were verified to be unique to the single individual differentiated cells lines. Hierarchical analysis underscored the limited similarities between HI-MSCs and BM-MSCs after induction of differentiation, and the persistence of relevant differences related to cells of different origin. CONCLUSIONS/SIGNIFICANCE: Proteomic analysis highlighted differences in the MSCs according to site of origin, reflecting spontaneous differentiation and commitment. A more detailed understanding of

  12. Imaging cyclic AMP changes in pancreatic islets of transgenic reporter mice.

    Directory of Open Access Journals (Sweden)

    Joung Woul Kim

    Full Text Available Cyclic AMP (cAMP and Ca(2+ are two ubiquitous second messengers in transduction pathways downstream of receptors for hormones, neurotransmitters and local signals. The availability of fluorescent Ca(2+ reporter dyes that are easily introduced into cells and tissues has facilitated analysis of the dynamics and spatial patterns for Ca(2+ signaling pathways. A similar dissection of the role of cAMP has lagged because indicator dyes do not exist. Genetically encoded reporters for cAMP are available but they must be introduced by transient transfection in cell culture, which limits their utility. We report here that we have produced a strain of transgenic mice in which an enhanced cAMP reporter is integrated in the genome and can be expressed in any targeted tissue and with tetracycline induction. We have expressed the cAMP reporter in beta-cells of pancreatic islets and conducted an analysis of intracellular cAMP levels in relation to glucose stimulation, Ca(2+ levels, and membrane depolarization. Pancreatic function in transgenic mice was normal. In induced transgenic islets, glucose evoked an increase in cAMP in beta-cells in a dose-dependent manner. The cAMP response is independent of (in fact, precedes the Ca(2+ influx that results from glucose stimulation of islets. Glucose-evoked cAMP responses are synchronous in cells throughout the islet and occur in 2 phases suggestive of the time course of insulin secretion. Insofar as cAMP in islets is known to potentiate insulin secretion, the novel transgenic mouse model will for the first time permit detailed analyses of cAMP signals in beta-cells within islets, i.e. in their native physiological context. Reporter expression in other tissues (such as the heart where cAMP plays a critical regulatory role, will permit novel biomedical approaches.

  13. Effect of fasting on 32P translocations in pre-labelled pancreatic islets

    International Nuclear Information System (INIS)

    The rapid, short-lived efflux of inorganic 32P-orthophosphate that occurs when pre-labelled pancreatic islets are exposed to nutrient insulin secretagogues (the ''phosphate flush'') has been proposed to reflect some early step in β-cell secretory activation. In the present study, glucose-initiated phosphate efflux was studied during fasting.Pancreatic islets were isolated from fed and 48-h fasted rats by collagenase digestion. After pre-labelling with 32P-orthophosphate and basal perifusion with 0.5 mg/ml glucose, tissue analyses disclosed similar stores of radioactivity in the two groups of islets. Stimulatory perfusion with glucose at this time failed to promote insulin release from islets which had been secured from fasted donors although the ''phosphate flush'' was preserved. However, the characteristics of phosphate efflux were altered. Maximal glucose-induced phosphate release was greater with islets from fasted animals whereas phosphate release in response to low level stimulation with glucose was diminished. Accordingly, the dose-response curve for glucose-initiated phosphate efflux in islets from fasted rats was displaced to the right and compatible with a decreased sensitivity to glucose at the activation site for the ''phosphate flush.'' Thus, while glucose is unable to enhance insulin release in vitro after fasting, glucose still elicits increased phosphate efflux. However, the phenomenon appears to be attended by an impaired responsiveness to activation by glucose, supporting the contention that some early step in the sequence of stimulus secretion coupling in the β-cell may be obtunded after food deprivation. (author)

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

    International Nuclear Information System (INIS)

    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 (Lepob/ob/HSL-/-) and explored the role of HSL in pancreatic β-cells in the setting of obesity. Lepob/ob/HSL-/- developed elevated blood glucose levels and reduced plasma insulin levels compared with Lepob/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 Lepob/ob islets, leading to reduced glucose-stimulated insulin secretion. The deficiency of HSL also diminished the islet mass in Lepob/ob mice due to decreased cell proliferation. In conclusion, HSL affects insulin secretary capacity especially in the setting of obesity.

  15. Use of the Fluidigm C1 platform for RNA sequencing of single mouse pancreatic islet cells.

    Science.gov (United States)

    Xin, Yurong; Kim, Jinrang; Ni, Min; Wei, Yi; Okamoto, Haruka; Lee, Joseph; Adler, Christina; Cavino, Katie; Murphy, Andrew J; Yancopoulos, George D; Lin, Hsin Chieh; Gromada, Jesper

    2016-03-22

    This study provides an assessment of the Fluidigm C1 platform for RNA sequencing of single mouse pancreatic islet cells. The system combines microfluidic technology and nanoliter-scale reactions. We sequenced 622 cells, allowing identification of 341 islet cells with high-quality gene expression profiles. The cells clustered into populations of α-cells (5%), β-cells (92%), δ-cells (1%), and pancreatic polypeptide cells (2%). We identified cell-type-specific transcription factors and pathways primarily involved in nutrient sensing and oxidation and cell signaling. Unexpectedly, 281 cells had to be removed from the analysis due to low viability, low sequencing quality, or contamination resulting in the detection of more than one islet hormone. Collectively, we provide a resource for identification of high-quality gene expression datasets to help expand insights into genes and pathways characterizing islet cell types. We reveal limitations in the C1 Fluidigm cell capture process resulting in contaminated cells with altered gene expression patterns. This calls for caution when interpreting single-cell transcriptomics data using the C1 Fluidigm system. PMID:26951663

  16. Mitochondrial priming modifies Ca2+ oscillations and insulin secretion in pancreatic islets.

    Science.gov (United States)

    Ainscow, E K; Rutter, G A

    2001-01-15

    Increases in mitochondrial [Ca(2+)] ([Ca(2+)](m)) have recently been reported to cause long-term alterations in cellular ATP production [Jouaville, Bastianutto, Rutter and Rizzuto (1999) Proc. Natl. Acad. Sci. U.S.A. 96, 13807-13812]. We have determined the importance of this phenomenon for nutrient sensing in pancreatic islets and beta-cells by imaging adenovirally expressed Ca(2+) and ATP sensors (aequorin and firefly luciferase). [Ca(2+)](m) increases provoked by KCl or tolbutamide evoked an immediate increase in cytosolic and mitochondrial free ATP concentration ([ATP](c) and [ATP](m) respectively) at 3 mM glucose. Subsequent increases in [glucose] (to 16 or 30 mM) then caused a substantially larger increase in [ATP](c) and [ATP](m) than in naïve cells, and pre-stimulation with tolbutamide led to a larger secretory response in response to glucose. Whereas pre-challenge of islets with KCl altered the response to high [glucose] of [Ca(2+)](m) from periodic oscillations to a sustained elevation, oscillations in [ATP](c) were observed neither in naïve nor in stimulated islets. Hence, long-term potentiation of mitochondrial ATP synthesis is a central element in nutrient recognition by pancreatic islets.

  17. Exercise at anaerobic threshold intensity and insulin secretion by isolated pancreatic islets of rats

    OpenAIRE

    de Oliveira, Camila Aparecida Machado; Paiva, Mauricio Ferreira; Mota, Clécia Alencar Soares; Ribeiro, Carla; de Almeida Leme, José Alexandre Curiacos; Luciano, Eliete; de Mello, Maria Alice Rostom

    2010-01-01

    To evaluate the effect of acute exercise and exercise training at the anaerobic threshold (AT) intensity on aerobic conditioning and insulin secretion by pancreatic islets, adult male Wistar rats were submitted to the lactate minimum test (LMT) for AT determination. Half of the animals were submitted to swimming exercise training (trained), 1 h/day, 5 days/week during 8 weeks, with an overload equivalent to the AT. The other half was kept sedentary. At the end of the experimental period, the ...

  18. Expression of innate immunity genes and damage of primary human pancreatic islets by epidemic strains of Echovirus: implication for post-virus islet autoimmunity.

    Directory of Open Access Journals (Sweden)

    Luis Sarmiento

    Full Text Available Three large-scale Echovirus (E epidemics (E4,E16,E30, each differently associated to the acute development of diabetes related autoantibodies, have been documented in Cuba. The prevalence of islet cell autoantibodies was moderate during the E4 epidemic but high in the E16 and E30 epidemic. The aim of this study was to evaluate the effect of epidemic strains of echovirus on beta-cell lysis, beta-cell function and innate immunity gene expression in primary human pancreatic islets. Human islets from non-diabetic donors (n = 7 were infected with the virus strains E4, E16 and E30, all isolated from patients with aseptic meningitis who seroconverted to islet cell antibody positivity. Viral replication, degree of cytolysis, insulin release in response to high glucose as well as mRNA expression of innate immunity genes (IFN-b, RANTES, RIG-I, MDA5, TLR3 and OAS were measured. The strains of E16 and E30 did replicate well in all islets examined, resulting in marked cytotoxic effects. E4 did not cause any effects on cell lysis, however it was able to replicate in 2 out of 7 islet donors. Beta-cell function was hampered in all infected islets (P<0.05; however the effect of E16 and E30 on insulin secretion appeared to be higher than the strain of E4. TLR3 and IFN-beta mRNA expression increased significantly following infection with E16 and E30 (P<0.033 and P<0.039 respectively. In contrast, the expression of none of the innate immunity genes studied was altered in E4-infected islets. These findings suggest that the extent of the epidemic-associated islet autoimmunity may depend on the ability of the viral strains to damage islet cells and induce pro-inflammatory innate immune responses within the infected islets.

  19. 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.

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

    International Nuclear Information System (INIS)

    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.

  1. Highly efficient adenoviral transduction of pancreatic islets using a microfluidic device.

    Science.gov (United States)

    Silva, Pamuditha N; Atto, Zaid; Regeenes, Romario; Tufa, Uilki; Chen, Yih Yang; Chan, Warren C W; Volchuk, Allen; Kilkenny, Dawn M; Rocheleau, Jonathan V

    2016-08-01

    Tissues are challenging to genetically manipulate due to limited penetration of viral particles resulting in low transduction efficiency. We are particularly interested in expressing genetically-encoded sensors in ex vivo pancreatic islets to measure glucose-stimulated metabolism, however poor viral penetration biases these measurements to only a subset of cells at the periphery. To increase mass transfer of viral particles, we designed a microfluidic device that holds islets in parallel hydrodynamic traps connected by an expanding by-pass channel. We modeled viral particle flow into the tissue using fluorescently-labelled gold nanoparticles of varying sizes and showed a penetration threshold of only ∼5 nm. To increase this threshold, we used EDTA to transiently reduce cell-cell adhesion and expand intercellular space. Ultimately, a combination of media flow and ETDA treatment significantly increased adenoviral transduction to the core of the islet. As proof-of-principle, we used this protocol to transduce an ER-targeted redox sensitive sensor (eroGFP), and revealed significantly greater ER redox capacity at core islet cells. Overall, these data demonstrate a robust method to enhance transduction efficiency of islets, and potentially other tissues, by using a combination of microfluidic flow and transient tissue expansion. PMID:27378588

  2. Fentanyl inhibits glucose-stimulated insulin release from β-cells in rat pancreatic islets

    Institute of Scientific and Technical Information of China (English)

    Tao-Lai Qian; Xin-Hua Wang; Sheng Liu; Liang Ma; Ying Lu

    2009-01-01

    AIM:To explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture.METHODS: Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile duct intraductal collagenase V digestion and were purified by discontinuous Ficoll density gradient centrifugation.The islets were divided into four groups according to the fentanyl concentration: control group (0 ng/mL),group Ⅰ (0.3 ng/mL), group Ⅱ (3.0 ng/mL), and group Ⅲ (30 ng/mL). In each group, the islets were co-cultured for 48 h with drugs under static conditions with fentanyl alone, fentanyl + 0.1 μg/mL naloxone or fentanyl + 1.0 μg/mL naloxone. Cell viability was assessed by the MTT assay. Insulin release in response to low and high concentrations (2.8 mmol/L and 16.7 mmol/L,respectively) of glucose was investigated and electron microscopy morphological assessment was performed.RESULTS: Low- and high-glucose-stimulated insulin release in the control group was significantly higher than in groups Ⅱ and Ⅲ (62.33 ±9.67 μIU vs 47.75 ±96.17 ± 14.17 μIU, 75.17 ± 13.57 μIU, respectively, P <0.01) and was lowest in group Ⅲ ( P < 0.01). After adding 1 μg/mL naloxone, insulin release in groups Ⅱ and Ⅲ was not different from the control group. Electron microscopy studies showed that the islets were damaged by 30 ng/mL fentanyl.CONCLUSION: Fentanyl inhibited glucose-stimulated insulin release from rat islets, which could be prevented by naloxone. Higher concentrations of fentanyl significantly damaged β-cells of rat islets.howed that the isl

  3. α1-antitrypsin increases interleukin-1 receptor antagonist production during pancreatic islet graft transplantation.

    Science.gov (United States)

    Abecassis, Avishag; Schuster, Ronen; Shahaf, Galit; Ozeri, Eyal; Green, Ross; Ochayon, David E; Rider, Peleg; Lewis, Eli C

    2014-07-01

    Although islet transplantation for individuals with type 1 diabetes has been shown to yield superior blood glucose control, it remains inadequate for long-term control. This is partly due to islet injuries and stresses that can lead to beta cell loss. Inhibition of excess IL-1β activity might minimize islet injuries, thus preserving function. The IL-1 receptor antagonist (IL-1Ra), an endogenous inhibitor of IL-1β, protects islets from cytokine-induced necrosis and apoptosis. Therefore, an imbalance between IL-1β and IL-1Ra might influence the courses of allogeneic and autoimmune responses to islets. Our group previously demonstrated that the circulating serine-protease inhibitor human alpha-1-antitrypsin (hAAT), the levels of which increase in circulation during acute-phase immune responses, exhibits anti-inflammatory and islet-protective properties, as well as immunomodulatory activity. In the present study, we sought to determine whether the pancreatic islet allograft-protective activity of hAAT was mediated by IL-1Ra induction. Our results demonstrated that hAAT led to a 2.04-fold increase in IL-1Ra expression in stimulated macrophages and that hAAT-pre-treated islet grafts exhibited a 4.851-fold increase in IL-1Ra transcript levels, which were associated with a moderate inflammatory profile. Unexpectedly, islets that were isolated from IL-1Ra-knockout mice and pre-treated with hAAT before grafting into wild-type mice yielded an increase in intragraft IL-1Ra expression that was presumably derived from infiltrating host cells, albeit in the absence of hAAT treatment of the host. Indeed, hAAT-pre-treated islets generated hAAT-free conditioned medium that could induce IL-1Ra production in cultured macrophages. Finally, we demonstrated that hAAT promoted a distinct phosphorylation and nuclear translocation pattern for p65, a key transcription factor required for IL-1Ra expression. PMID:25000533

  4. 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

  5. Demonstration of pepsinogen C in human pancreatic islets

    DEFF Research Database (Denmark)

    Poulsen, Steen Seier

    1987-01-01

    Pancreatic tissue from 16 post mortem kidney donors have been examined for the content of pepsinogens. A zymogen with electrophoretic mobility, isoelectric point and molecular weight equal to that of pepsinogen C of gastric origin was found in all specimens. A comparison between pepsinogen C extr...

  6. Isolation, Culture and Induced Differentiation of Fetal Porcine Islet Derived Pancreatic Stem Cell

    Institute of Scientific and Technical Information of China (English)

    FENG Ruo-peng; ZHANG Hui-ru; WANG Yun; QIAO Hai; ZHAO Ting; SHEN Wen-zheng; DOU Zhong-ying

    2007-01-01

    To isolate and culture the porcine pancreatic stem cells and investigate their function, the fetal porcine pancreatic stem cells were isolated by the method of suspending plus adhering culture. The isolated cells were then identified by irnmunohistochemical staining, and their culture viability measured through the MTT method in vitro. This induced them to differentiate into endocrine cells and detect their function. The isolated IPSCS did not express nestin, but expressed CK-19, a marker of ductal epithelia cells and oc-actin, a smooth muscle marker, demonstrating the growth characteristics of ES-like cells, and strong proliferative ability, after 18 passages. They could excrete insulin, and showed ultrastructure changes after being induced. Porcine pancreatic stem cells can be isolated by this method, induced to form islet-like clusters, and can secret insulin.

  7. Cyproheptadine metabolites inhibit proinsulin and insulin biosynthesis and insulin release in isolated rat pancreatic islets

    Energy Technology Data Exchange (ETDEWEB)

    Chow, S.A.; Falany, J.L.; Fischer, L.J. (Univ. of Iowa, Iowa City (USA))

    1989-06-01

    The contribution of drug metabolites to cyproheptadine (CPH)-induced alterations in endocrine pancreatic beta-cells was investigated by examining the inhibitory activity of CPH and its biotransformation products, desmethylcyproheptadine (DMCPH), CPH-epoxide and DMCPH-epoxide, on hormone biosynthesis and secretion in pancreatic islets isolated from 50-day-old rats. Measurement of (pro)insulin (proinsulin and insulin) synthesis using incorporation of 3H-leucine showed that DMCPH-epoxide, DMCPH and CPH-epoxide were 22, 10 and 4 times, respectively, more potent than CPH in inhibiting hormone synthesis. The biosynthesis of (pro)insulin was also inhibited by CPH and DMCPH-epoxide in islets isolated from 21-day-old rat fetuses. The inhibitory action of CPH and its metabolites was apparently specific for (pro)insulin, and the synthesis of other islet proteins was not affected. Other experiments showed the metabolites of CPH were active in inhibiting glucose-stimulated insulin secretion but were less potent than the parent drug in producing this effect. CPH and its structurally related metabolites, therefore, have differential inhibitory activities on insulin synthesis and release. The observation that CPH metabolites have higher potency than CPH to inhibit (pro)insulin synthesis, when considered with published reports on the disposition of the drug in rats, indicate that CPH metabolites, particularly DMCPH-epoxide, are primarily responsible for the insulin depletion observed when the parent compound is given to fetal and adult animals.

  8. Cyproheptadine metabolites inhibit proinsulin and insulin biosynthesis and insulin release in isolated rat pancreatic islets

    International Nuclear Information System (INIS)

    The contribution of drug metabolites to cyproheptadine (CPH)-induced alterations in endocrine pancreatic beta-cells was investigated by examining the inhibitory activity of CPH and its biotransformation products, desmethylcyproheptadine (DMCPH), CPH-epoxide and DMCPH-epoxide, on hormone biosynthesis and secretion in pancreatic islets isolated from 50-day-old rats. Measurement of (pro)insulin (proinsulin and insulin) synthesis using incorporation of 3H-leucine showed that DMCPH-epoxide, DMCPH and CPH-epoxide were 22, 10 and 4 times, respectively, more potent than CPH in inhibiting hormone synthesis. The biosynthesis of (pro)insulin was also inhibited by CPH and DMCPH-epoxide in islets isolated from 21-day-old rat fetuses. The inhibitory action of CPH and its metabolites was apparently specific for (pro)insulin, and the synthesis of other islet proteins was not affected. Other experiments showed the metabolites of CPH were active in inhibiting glucose-stimulated insulin secretion but were less potent than the parent drug in producing this effect. CPH and its structurally related metabolites, therefore, have differential inhibitory activities on insulin synthesis and release. The observation that CPH metabolites have higher potency than CPH to inhibit (pro)insulin synthesis, when considered with published reports on the disposition of the drug in rats, indicate that CPH metabolites, particularly DMCPH-epoxide, are primarily responsible for the insulin depletion observed when the parent compound is given to fetal and adult animals

  9. 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.

  10. Protective efficacy of folic acid and vitamin B12 against nicotine-induced toxicity in pancreatic islets of the rat

    Science.gov (United States)

    Bhattacharjee, Ankita; Prasad, Shilpi Kumari; Pal, Swagata; Maji, Bithin; Syamal, Alak Kumar; Banerjee, Arnab

    2015-01-01

    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. Protective efficacy of folic acid and vitamin B12 against nicotine-induced toxicity in pancreatic islets of the rat

    Science.gov (United States)

    Bhattacharjee, Ankita; Prasad, Shilpi Kumari; Pal, Swagata; Maji, Bithin; Syamal, Alak Kumar; Banerjee, Arnab

    2015-01-01

    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. PMID:27486368

  12. 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.

  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. Three-dimensional image study on the vascular structure after angiopoietin-1 transduction in isolated mouse pancreatic islets

    Science.gov (United States)

    He, Jing; Su, Dongming; Trucco, Massimo

    2008-02-01

    Angiopoietin-1 (Ang-1) is essential for remodeling the primitive vascular plexus during embryonic development and for reducing plasma leakage in inflammation of adult vasculature. However, the role for Ang-1 in maintenance of vascular stability in isolated pancreatic islets is not fully understood. In this study, we compared the difference of vascular morphology between Ang-1 treated (n=5) and control mouse islets (n=5) using both two- and three-dimensional optical image analysis. Isolated mouse islets were transduced with Ang-1 or Lac Z (control) vector at 37°C for 16 hours. Islets were incubated with both rat anti-CD31 antibody and rabbit anti-insulin antibody followed by incubation with Rhodamine-conjugated goat anti-rat IgG and Alexa-488 conjugated goat anti-rabbit IgG. Islets were viewed under a Nikon confocal microscope. Serial optical section images were captured and reconstructed using Nikon EZ-C1 software. Individual two-D and reconstructed three-D images were analyzed using MetaMorph Image Analysis software. Islet vascular density was determined. In two-D images, there was no significant difference of vascular density between the two groups. The vascular morphology didn't show any obvious differences in two-D images either. However, in the three-D images, we found higher vascular density and more vascular branches in the Ang-1 transducted islets and vascular dilation in control group. In conclusion, using three-D image analysis, Ang-1 displayed functions in maintenance of vascular stability and in stimulating growth of vascular branches in isolated mouse pancreatic islets. In order to study further the regeneration of different cell contents in the spherical pancreatic islet, three-D image analysis is an effective method to approach this goal.

  15. Simultaneous determination of the content of serotonin, dopamine, noradrenaline and adrenaline in pancreatic islets isolated from fed and starved mice

    International Nuclear Information System (INIS)

    A highly sensitive double isotope method for the simultaneous determination of serotonin, dopamine, noradrenaline and adrenaline has been developed. Advantages and limitations of the method are discussed. The mentioned biogenic amines are all present in isolated pancreatic islet tissue from albino mice in concentrations ranging from approximately 5-30 μmol per kg wet weight (0.8-5 x 10-3 pmol/ng DNA). A somewhat higher content of these amines, especially dopamine, was found in pancreatic acinar tissue. The hypothesis that the impaired glucose-induced insulin secretion during starvation partly is caused by an increased content of biogenic amines in the pancreatic islets was not supported by our experiments which showed an unchanged islet content of these amines after 48 h starvation. (author)

  16. Differentiation of fetal pancreatic stem cells into neuron-like and islet-like cells in vitro

    Institute of Scientific and Technical Information of China (English)

    Xiufeng Hua; Yanwei Wang; Peiwen Lian; Shouxin Zhang; Jianyuan Li; Haiyan Wang; Shulin Chen; Wei Gao

    2012-01-01

    Pancreatic stem cells were isolated and cultured from aborted human fetal pancreases of gestational age 14-20 weeks.They were seeded at a density of 1 × 104 in serum-free media for differentiation into neuron-like cells, expressing β-tubulin III and glial fibrillary acidic protein.These neuron-like cells displayed a synapse-like morphology and appeared to form a neuronal network.Pancreatic stem cells were also seeded at a density of 1 × 105 for differentiation into islet-like cells, expressing insulin and glucagon, with an islet-like morphology.These cells had glucose-stimulated secretion of human insulin and C-peptide.Results suggest that pancreatic stem cells can be differentiated into neuron-like and islet-like cells.

  17. 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-4a...... insulin in response to glucose stimulation than islets from wild-type littermates. It is concluded that GPR39 is involved in the control of endocrine pancreatic function, and it is suggested that this receptor could be a novel potential target for the treatment of diabetes.......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......alpha, and in the present study, we addressed the importance of GPR39 for glucose homeostasis and pancreatic islets function. The expression and localization of GPR39 were characterized in the endocrine pancreas and pancreatic cell lines. Gpr39(-/-) mice were studied in vivo, especially in respect of...

  18. Protective effect of ganoderma lucidum polysaccharides on pancreatic islet in type 2 diabetes mellitus rats

    International Nuclear Information System (INIS)

    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)

  19. Induction of beta-cell resistance to hypoxia and technologies for oxygen delivery to transplanted pancreatic islets.

    Science.gov (United States)

    Lazard, Daniel; Vardi, Pnina; Bloch, Konstantin

    2012-09-01

    Hypoxia is believed to be a crucial factor involved in cell adaptation to environmental stress. Islet transplantation, especially with immunoisolated islets, interrupts vascular connections, resulting in the substantially decreased delivery of oxygen and nutrients to islet cells. Insulin-producing pancreatic beta cells are known to be highly susceptible to oxygen deficiency. Such susceptibility to hypoxia is believed to be one of the main causes of beta-cell death in the post-transplantation period. Different strategies have been developed for the protection of beta cells against hypoxic injury and for oxygen delivery to transplanted islets. The enhancement of beta-cell defense properties against hypoxia has been achieved using various techniques such as gene transfection, drug supplementation, co-culturing with stem cells and cell selection. Technologies for oxygen delivery to transplanted islets include local neovascularization of subcutaneous sites, electrochemical and photosynthetic oxygen generation, oxygen refuelling of bio-artificial pancreas and whole body oxygenation by using hyperbaric therapy. Progress in the field of oxygen technologies for islet transplantation requires a multidisciplinary approach to explore and optimize the interaction between components of the biological system and different technological processes. This review article focuses mainly on the recently developed strategies for oxygenation and protection from hypoxic injury - to achieve stable and long-term normoglycaemia in diabetic patients with transplanted pancreatic islets. PMID:22389124

  20. Geometric phase transition in the cellular network of the pancreatic islets may underlie the onset of type 1diabetes

    Science.gov (United States)

    Wang, Xujing

    Living systems are characterized by complexity in structure and emergent dynamic orders. In many aspects the onset of a chronic disease resembles phase transition in a 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 investigate this idea in a real example, the insulin-producing pancreatic islet β-cells and the onset of type 1 diabetes. Within each islet, the β-cells are electrically coupled to each other, and function as a network with synchronized actions. Using percolation theory we show how normal islet function is intrinsically linked to network connectivity, and the critical point where the islet cellular network loses site percolation, is consistent with laboratory and clinical observations of the threshold β-cell loss that causes islet functional failure. 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 disease onset and introduction of treatment, potentially explaining a long time mystery in the clinical study of type 1 diabetes: the honeymoon phenomenon. Based on these results, we hypothesized that the onset of T1D may be the result of a phase transition of the islet β-cell network. We further discuss the potential applications in identifying disease-driving factors, and the critical parameters that are predictive of disease onset.

  1. Total Pancreatectomy and Islet Auto-Transplantation as Treatment for Ampullary Adenocarcinoma in the Setting of Pancreatic Ductal Disruption Secondary to Acute Necrotizing Pancreatitis. A Case Report

    Directory of Open Access Journals (Sweden)

    Uroghupatei P Iyegha

    2012-03-01

    Full Text Available Context Ampullary adenocarcinoma is the third most common periampullary malignancy. Obstruction of the main pancreatic duct is linked with an increased incidence of acute pancreatitis. Acute necrotizing pancreatitis leading to pancreatic duct disruption carries significant morbidity. When these conditions occur in combination, the treatment can be drastically limited as pancreaticoduodenectomy is not a viable option in the setting of friable ductal tissue, which precludes pancreatic ductal anastomosis and can lead to the complications of leak or stricture. Case report Our patient is a 72-year-old woman who developed pancreatic ductal disruption and splenic vein thrombosis as a result of acute necrotizing pancreatitis. Concurrently, she was found to have an ampullary adenoma with high-grade dysplasia. Her treatment options were limited, as she was neither a candidate for pancreaticoduodenectomy given the ductal disruption nor total pancreatectomy, which would render her a brittle diabetic. She was successfully treated with total pancreatectomy and islet auto-transplantation thereby resecting her ampullary lesion while both avoiding a pancreatic anastomosis and preserving pancreatic endocrine beta-cell function. Conclusion We report a case where total pancreatectomy and islet auto-transplantation can be considered as a viable option for treatment of ampullary lesions in a setting where standard surgical options are suboptimal.

  2. Histomorphological and morphometric studies of the pancreatic islet cells of diabetic rats treated with extracts of Annona muricata.

    Science.gov (United States)

    Adeyemi, D O; Komolafe, O A; Adewole, O S; Obuotor, E M; Abiodun, A A; Adenowo, T K

    2010-05-01

    Microanatomical changes in the pancreatic islet cells of streptozotocin induced diabetic Wistar rats were studied after treatment with methanolic extracts of Annona muricata leaves. Thirty adult Wistar rats were randomly assigned into three groups (control, untreated diabetic group, and A. muricata-treated diabetic group) of ten rats each. Diabetes mellitus was experimentally induced in groups B and C by a single intra-peritoneal injection of 80 mg/kg streptozotocin dissolved in 0.1 M citrate buffer. The control rats were intraperitoneally injected with an equivalent volume of citrate buffer. Daily intra peritoneal injections of 100 mg/kg A. muricata were administered to group C rats for two weeks. Post sacrifice the pancreases of the rats were excised and fixed in Bouin's fluid. The tissues were processed for paraffin embedding and sections of 5 mum thickness were produced and stained with H & E, Gomori aldehyde fuchsin, and chrome alum haematoxylin-phloxine for demonstration of the beta-cells of islets of pancreatic islets. Histomorphological and morphometric examination of the stained pancreatic sections showed a significant increase in the number, diameter, and volume of the beta-cells of pancreatic islets of the A. muricata-treated group (5.67 +/- 0.184 N/1000 mum(2), 5.38 +/- 0.093 mum and 85.12 +/- 4.24 mum(3), respectively) when compared to that of the untreated diabetic group of rats (2.85 +/- 0.361 N/1000 mum(2), 2.85 +/- 0.362 mum and 69.56 +/- 5.216 mum(3), respectively). The results revealed regeneration of the beta-cells of islets of pancreatic islet of rats treated with extract of A. muricata.

  3. Zebularine induces long-term survival of pancreatic islet allotransplants in streptozotocin treated diabetic rats.

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    Henrietta Nittby

    Full Text Available BACKGROUND: Coping with the immune rejection of allotransplants or autologous cells in patients with an active sensitization towards their autoantigens and autoimmunity presently necessitates life-long immune suppressive therapy acting on the immune system as a whole, which makes the patients vulnerable to infections and increases their risk of developing cancer. New technologies to induce antigen selective long-lasting immunosuppression or immune tolerance are therefore much needed. METHODOLOGY/PRINCIPAL FINDINGS: The DNA demethylating agent Zebularine, previously demonstrated to induce expression of the genes for the immunosuppressive enzymes indolamine-2,3-deoxygenase-1 (IDO1 and kynureninase of the kynurenine pathway, is tested for capacity to suppress rejection of allotransplants. Allogeneic pancreatic islets from Lewis rats were transplanted under the kidney capsule of Fischer rats previously made diabetic by a streptozotocin injection (40 mg/kg. One group was treated with Zebularine (225 mg/kg daily for 14 days from day 6 or 8 after transplantation, and a control group received no further treatment. Survival of the transplants was monitored by blood sugar measurements. Rats, normoglycemic for 90 days after allografting, were subjected to transplant removal by nephrectomy to confirm whether normoglycemia was indeed due to a surviving insulin producing transplant, or alternatively was a result of recovery of pancreatic insulin production in some toxin-treated rats. Of 9 Zebularine treated rats, 4 were still normoglycemic after 90 days and became hyperglycemic after nephrectomy. The mean length of normoglycemia in the Zebularine group was 67±8 days as compared to 14±3 days in 9 controls. Seven rats (2 controls and 5 Zebularine treated were normoglycemic at 90 days due to pancreatic recovery as demonstrated by failure of nephrectomy to induce hyperglycemia. CONCLUSIONS/SIGNIFICANCE: Zebularine treatment in vivo induces a long

  4. The Edges of Pancreatic Islet β Cells Constitute Adhesive and Signaling Microdomains

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    Erez Geron

    2015-01-01

    Full Text Available Pancreatic islet β cells are organized in rosette-like structures around blood vessels and exhibit an artery-to-vein orientation, but they do not display the typical epithelial polarity. It is unclear whether these cells present a functional asymmetry related to their spatial organization. Here, we identify murine β cell edges, the sites at which adjacent cell faces meet at a sharp angle, as surface microdomains of cell-cell adhesion and signaling. The edges are marked by enrichment of F-actin and E-cadherin and are aligned between neighboring cells. The edge organization is E-cadherin contact dependent and correlates with insulin secretion capacity. Edges display elevated levels of glucose transporters and SNAP25 and extend numerous F-actin-rich filopodia. A similar β cell edge organization was observed in human islets. When stimulated, β cell edges exhibit high calcium levels. In view of the functional importance of intra-islet communication, the spatial architecture of their edges may prove fundamental for coordinating physiological insulin secretion.

  5. Effect of copper deficiency on the content and secretion of pancreatic islet hormones

    Energy Technology Data Exchange (ETDEWEB)

    Bhathena, S.J.; Voyles, N.R.; Timmers, K.I.; Fields, M.; Kennedy, B.W.; Recant, L.

    1986-03-01

    Experimental copper (Cu) deficiency in rats is characterized by glucose intolerance and hyperlipemia. Its severity is increased by dietary fructose (F) as compared to starch (S). Since islet hormones are intimately involved in carbohydrate metabolism the authors studied the effects of Cu deficiency on their content and secretion. Rats were fed Cu deficient (CuD) (0.6 ..mu..g Cu/g) or Cu supplemented (6.0 ..mu..g Cu/g) diets with either 62% F or S for 7 weeks after weaning. Feeding CuD diets decreased plasma insulin (I) (P < 0.001) but not plasma glucagon (G). F feeding compared to S magnified the effects of Cu deficiency. Total pancreatic content of I in CuD rats was increased threefold (P < 0.001). Total somatostatin content increased significantly only in the pancreas of CuD rats fed F. Although total G content was not altered in CuD rats, when G was expressed per g protein or g wet weight, significant increases were found in CuD rats fed F. Thus, of the islet hormones, the major effect of Cu deficiency was on I. When pancreata were perfused in vitro with high glucose, pancreas from CuD rats had reduced insulin response. Thus, cellular functions dependent on Cu are involved in maintaining the ability of the islets of Langerhans to secrete I in a normal fashion.

  6. Assembly of bioactive multilayered nanocoatings on pancreatic islet cells: incorporation of α1-antitrypsin into the coatings.

    Science.gov (United States)

    Zhi, Zheng-Liang; Singh, Jashandeep; Austin, Amazon L F; Hope, David C D; King, Aileen J; Persaud, Shanta J; Jones, Peter M

    2015-07-01

    A spontaneous multilayer deposition approach for presenting therapeutic proteins onto pancreatic islet surfaces, using a heparin polyaldehyde and glycol chitosan alternating layering scheme, has been developed to enable the nanoscale engineering of a microenvironment for transplanted cells. The nanocoating incorporating α1-antitrypsin, an anti-inflammatory protein, exhibited effective anti-coagulant activities in vitro. PMID:26051448

  7. Delineation of glutamate pathways and secretory responses in pancreatic islets with β-cell-specific abrogation of the glutamate dehydrogenase

    DEFF Research Database (Denmark)

    Vetterli, Laurène; Carobbio, Stefania; Pournourmohammadi, Shirin;

    2012-01-01

    In pancreatic β-cells, glutamate dehydrogenase (GDH) modulates insulin secretion, although its function regarding specific secretagogues is unclear. This study investigated the role of GDH using a β-cell-specific GDH knockout mouse model, called βGlud1(-/-). The absence of GDH in islets isolated ...

  8. Unraveling the effects of 1,25(OH)(2)D-3 on global gene expression in pancreatic islets

    DEFF Research Database (Denmark)

    Wolden-Kirk, H.; Overbergh, L.; Gysemans, C.;

    2013-01-01

    Introduction: Vitamin D deficiency has been linked to type 1 and 2 diabetes, whereas supplementation may prevent both diseases. However, the extent of the effects of vitamin D or its metabolites directly on pancreatic islets is still largely unknown. The aim of the present study was to investigat...

  9. Cytokines inducing bone marrow SCA+ cells migration into pancreatic islet and conversion into insulin-positive cells in vivo.

    Directory of Open Access Journals (Sweden)

    LuGuang Luo

    Full Text Available We hypothesize that specific bone marrow lineages and cytokine treatment may facilitate bone marrow migration into islets, leading to a conversion into insulin producing cells in vivo. In this study we focused on identifying which bone marrow subpopulations and cytokine treatments play a role in bone marrow supporting islet function in vivo by evaluating whether bone marrow is capable of migrating into islets as well as converting into insulin positive cells. We approached this aim by utilizing several bone marrow lineages and cytokine-treated bone marrow from green fluorescent protein (GFP positive bone marrow donors. Sorted lineages of Mac-1(+, Mac-1(-, Sca(+, Sca(-, Sca(-/Mac-1(+ and Sca(+/Mac-1(- from GFP positive mice were transplanted to irradiated C57BL6 GFP negative mice. Bone marrow from transgenic human ubiquitin C promoter GFP (uGFP, with strong signal C57BL6 mice was transplanted into GFP negative C57BL6 recipients. After eight weeks, migration of GFP positive donor' bone marrow to the recipient's pancreatic islets was evaluated as the percentage of positive GFP islets/total islets. The results show that the most effective migration comes from the Sca(+/Mac(- lineage and these cells, treated with cytokines for 48 hours, were found to have converted into insulin positive cells in pancreatic islets in vivo. This study suggests that bone marrow lineage positive cells and cytokine treatments are critical factors in determining whether bone marrow is able to migrate and form insulin producing cells in vivo. The mechanisms causing this facilitation as well as bone marrow converting to pancreatic beta cells still need to be investigated.

  10. The effect of lesions of the sympathoadrenal system on training induced adaptations in adipocytes and pancreatic islets in rats

    DEFF Research Database (Denmark)

    Stallknecht, B; Roesdahl, M; Vinten, J;

    1996-01-01

    Physical training increases insulin stimulated glucose uptake in adipocytes and decreases insulin secretion from pancreatic islets. The mechanism behind these adaptations is not known. Because in acute exercise adrenergic activity influences both adipocytes and pancreatic islets, the sympathetic...... in sham adrenodemedullated rats (P muscle noradrenaline content in sympathectomized leg was 9% of content in sham sympathectomized leg (P trained for 10 weeks or remained sedentary. Insulin stimulated 3-O-[14C]methylglucose transport...... that adrenergic activity is not important for the training induced decrease in size and increase in insulin stimulated glucose transport of adipocytes. Neither is an intact adrenal medulla necessary for training-induced adaptations in pancreatic beta cell function. Finally, in response to training, beta cell...

  11. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Kahkashan; Sil, Parames C., E-mail: parames@jcbose.ac.in

    2015-02-01

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  12. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    International Nuclear Information System (INIS)

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  13. Global gene expression profiling of pancreatic islets in mice during streptozotocin-induced β-cell damage and pancreatic Glp-1 gene therapy

    Directory of Open Access Journals (Sweden)

    Jason M. Tonne

    2013-09-01

    Streptozotocin (STZ, a glucosamine-nitrosourea compound, has potent genotoxic effects on pancreatic β-cells and is frequently used to induce diabetes in experimental animals. Glucagon-like peptide-1 (GLP-1 has β-cell protective effects and is known to preserve β-cells from STZ treatment. In this study, we analyzed the mechanisms of STZ-induced diabetes and GLP-1-mediated β-cell protection in STZ-treated mice. At 1 week after multiple low-dose STZ administrations, pancreatic β-cells showed impaired insulin expression, while maintaining expression of nuclear Nkx6.1. This was accompanied by significant upregulation of p53-responsive genes in islets, including a mediator of cell cycle arrest, p21 (also known as Waf1 and Cip1. STZ treatment also suppressed expression of a wide range of genes linked with key β-cell functions or diabetes development, such as G6pc2, Slc2a2 (Glut2, Slc30a8, Neurod1, Ucn3, Gad1, Isl1, Foxa2, Vdr, Pdx1, Fkbp1b and Abcc8, suggesting global β-cell defects in STZ-treated islets. The Tmem229B, Prss53 and Ttc28 genes were highly expressed in untreated islets and strongly suppressed by STZ, suggesting their potential roles in β-cell function. When a pancreas-targeted adeno-associated virus (AAV vector was employed for long-term Glp-1 gene delivery, pancreatic GLP-1 expression protected mice from STZ-induced diabetes through preservation of the β-cell mass. Despite its potent β-cell protective effects, however, pancreatic GLP-1 overexpression showed limited effects on the global gene expression profiles in the islets. Network analysis identified the programmed-cell-death-associated pathways as the most relevant network in Glp-1 gene therapy. Upon pancreatic GLP-1 expression, upregulation of Cxcl13 and Nptx2 was observed in STZ-damaged islets, but not in untreated normal islets. Given the pro-β-cell-survival effects of Cxcl12 (Sdf-1 in inducing GLP-1 production in α-cells, pancreatic GLP-1-mediated Cxcl13 induction might also play a

  14. Simulated Microgravity Reduces TNF-Alpha Activity, Suppresses Glucose Uptake and Enhances Arginine Flux in Pancreatic Islets of Langerhans

    Science.gov (United States)

    Tobin, Brian W.; Leeper-Woodford, Sandra K.; Hashemi, Brian B.; Smith, Scott M.; Sams, Clarence F.; Paloski, W. H. (Technical Monitor)

    2000-01-01

    The present studies were designed to determine effects of microgravity 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+/-117,150 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 (parginine in islets cultured in HARVs. While nitrogenous compound analysis indicated a ubiquitous reliance upon glutamine in all experimental groups, arginine was converted to ornithine at a two-fold greater rate in the islets cultured in the HARV microgravity paradigm (p<0.05). These studies demonstrate alterations in LPS induced TNF-alpha production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV paradigm. These alterations in fuel homeostasis may be promulgated by gravity averaged cell culture methods or by three dimensional cell assembly.

  15. Radical-scavenging effects of Aloe arborescens Miller on prevention of pancreatic islet B-cell destruction in rats.

    Science.gov (United States)

    Beppu, Hidehiko; Koike, Takaaki; Shimpo, Kan; Chihara, Takeshi; Hoshino, Motoyuki; Ida, Chikako; Kuzuya, Hiroshi

    2003-11-01

    We evaluated the possible scavenging effects of Aloe arborescens Miller var. natalensis Berger (Kidachi aloe in Japanese) on free radicals generated by streptozotocin (Sz) or alloxan (Ax). The components of Kidachi aloe were added to a reaction system in which .OH radicals derived from Sz or Ax as pancreatic islet B-cell toxins and hypoxanthine-xanthine oxidase (HX-XO)-derived O(2) radicals destroy isolated islet B-cells, and we observed its preventive effects. The Kidachi aloe components inhibited the destruction of rat pancreatic islet B-cells by Sz, Ax or HX-XO. These components were prepared in the form of a freeze-dried powder of the boiled leaf skin of Kidachi aloe, and measurement of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity showed higher radical-scavenging activity in this boiled leaf skin powder than the non-boiled leaf skin powder.Furthermore, HPLC chromatograms of the "Boiled leaf skin powder" were similar to those of commercially available aloin (barbaloin content: approximately 20%). Therefore, the main component may be a phenol compound. In addition, the phenolic fraction of the Boiled leaf skin contained large amounts of 2'-O-p-coumaroylaloesin and 2'-O-feruloylaloesin, which have higher DPPH radical-scavenging activity than barbaloin. These results suggest that the action mechanism of Kidachi aloe Boiled leaf skin components, which prevent destruction of the pancreatic islets by specific pancreatic islet toxins such as Sz, Ax, and HX-XO, involves inhibition of free radical-scavenging effects, and may be associated with a thermostable low molecular component. The co-existence of Kidachi aloe-derived 2'-O-p-coumaroylaloesin, 2'-O-feruloylaloesin, and aloin may result in the potentiation of radical-scavenging activity. PMID:14522430

  16. Effects of growth hormone, prolactin, and placental lactogen on insulin content and release, and deoxyribonucleic acid synthesis in cultured pancreatic islets

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    1982-01-01

    The direct effects of human GH (hGH), ovine pituitary PRL (oPRL), and human chorionic somatomammotropin [placental lactogen (hPL)] on the endocrine pancreas were studied in isolated pancreatic islets maintained in tissue culture. Islets of Langerhans were isolated by collagenase treatment of panc...

  17. Pancreatic islet-cell viability, functionality and oxidative status remain unaffected at pharmacological concentrations of commonly used antibiotics in vitro

    Indian Academy of Sciences (India)

    Yogita Shewade; Suraj Tirth; R R Bhonde

    2001-09-01

    Environmental factors such as diet, physical activity, drugs, pollution and life style play an important role in the progression and/or precipitation of diseases like diabetes, hypertension, obesity and cardiovascular disorders. Indiscriminate use of antibiotics to combat infectious diseases is one of the commonest forms of misuse of drugs. Antibiotics seem to have a correlation with diabetes and pancreatic function. There are controversial reports about the effect of antibiotics on the pancreatic islets; some suggesting their harmless action, some depicting a beneficial role and others indicating deleterious effect. Moreover, use of antibiotics is mandatory during islet isolation and cultivation to reduce incidences of microbial contamination. It is likely that antibiotic treatment may adversely affect islet viability and its functioning leading to failure of islet transplantation. The present in vitro study was undertaken to examine the effect of commonly used antibiotics such as gentamycin, penicillin, streptomycin, tetracycline, neomycin, erythromycin and chloramphenicol on islet viability, its functioning and induction of oxidative stress if any. The viability and insulin production data showed that none of the antibiotics used in the present study affect the viability and the functioning of the islets at their pharmacological concentrations. Free radical levels measured in terms of melonyldialdehyde (MDA), nitric oxide (NO) and reduced glutathione (GSH) reveal that except for a marginal increase in lipid peroxidation with tetracycline and slight increase in NO levels with streptomycin, none of these antibiotics affect the oxidative status of the cells. Antioxidant enzymes such as superoxide dismutase and catalase remain unaffected after this treatment. Our results reveal the innocuous nature of the antibiotics used at pharmacological concentrations, suggesting their safety whenever prescribed to combat infections and also during islet isolation procedures.

  18. Snapshot Hyperspectral Light-Sheet Imaging of Signal Transduction in Live Pancreatic Islets.

    Science.gov (United States)

    Lavagnino, Zeno; Dwight, Jason; Ustione, Alessandro; Nguyen, Thuc-Uyen; Tkaczyk, Tomasz S; Piston, David W

    2016-07-26

    The observation of ionic signaling dynamics in intact pancreatic islets has contributed greatly to our understanding of both α- and β-cell function. Insulin secretion from β-cells depends on the firing of action potentials and consequent rises of intracellular calcium activity ([Ca(2+)]i). Zinc (Zn(2+)) is cosecreted with insulin, and has been postulated to play a role in cell-to-cell cross talk within an islet, in particular inhibiting glucagon secretion from α-cells. Thus, measuring [Ca(2+)]i and Zn(2+) dynamics from both α- and β-cells will elucidate mechanisms underlying islet hormone secretion. [Ca(2+)]i and intracellular Zn(2+) can be measured using fluorescent biosensors, but the most efficient sensors have overlapping spectra that complicate their discrimination. Hyperspectral imaging can be used to distinguish signals from multiple fluorophores, but available hyperspectral implementations are either too slow to measure the dynamics of ionic signals or not suitable for thick samples. We have developed a five-dimensional (x,y,z,t,λ) imaging system that leverages a snapshot hyperspectral imaging method, image mapping spectrometry, and light-sheet microscopy. This system provides subsecond temporal resolution from deep within multicellular structures. Using a single excitation wavelength (488 nm) we acquired images from triply labeled samples with two biosensors and a genetically expressing fluorescent protein (spectrally overlapping with one of the biosensors) with high temporal resolution. Measurements of [Ca(2+)]i and Zn(2+) within both α- and β-cells as a function of glucose concentration show heterogeneous uptake of Zn(2+) into α-cells that correlates to the known heterogeneities in [Ca(2+)]i. These differences in intracellular Zn(2+) among α-cells may contribute to the inhibition in glucagon secretion observed at elevated glucose levels. PMID:27463142

  19. Glucagon-Like Peptide 1 Analogs and their Effects on Pancreatic Islets.

    Science.gov (United States)

    Tudurí, Eva; López, Miguel; Diéguez, Carlos; Nadal, Angel; Nogueiras, Rubén

    2016-05-01

    Glucagon-like peptide 1 (GLP-1) exerts many actions that improve glycemic control. GLP-1 stimulates glucose-stimulated insulin secretion and protects β cells, while its extrapancreatic effects include cardioprotection, reduction of hepatic glucose production, and regulation of satiety. Although an appealing antidiabetic drug candidate, the rapid degradation of GLP-1 by dipeptidyl peptidase 4 (DPP-4) means that its therapeutic use is unfeasible, and this prompted the development of two main GLP-1 therapies: long-acting GLP-1 analogs and DPP-4 inhibitors. In this review, we focus on the pancreatic effects exerted by current GLP-1 derivatives used to treat diabetes. Based on the results from in vitro and in vivo studies in humans and animal models, we describe the specific actions of GLP-1 analogs on the synthesis, processing, and secretion of insulin, islet morphology, and β cell proliferation and apoptosis. PMID:27062006

  20. TGFβ Pathway Inhibition Redifferentiates Human Pancreatic Islet β Cells Expanded In Vitro.

    Directory of Open Access Journals (Sweden)

    Ginat Toren-Haritan

    Full Text Available In-vitro expansion of insulin-producing cells from adult human pancreatic islets could provide an abundant cell source for diabetes therapy. However, proliferation of β-cell-derived (BCD cells is associated with loss of phenotype and epithelial-mesenchymal transition (EMT. Nevertheless, BCD cells maintain open chromatin structure at β-cell genes, suggesting that they could be readily redifferentiated. The transforming growth factor β (TGFβ pathway has been implicated in EMT in a range of cell types. Here we show that human islet cell expansion in vitro involves upregulation of the TGFβ pathway. Blocking TGFβ pathway activation using short hairpin RNA (shRNA against TGFβ Receptor 1 (TGFBR1, ALK5 transcripts inhibits BCD cell proliferation and dedifferentiation. Treatment of expanded BCD cells with ALK5 shRNA results in their redifferentiation, as judged by expression of β-cell genes and decreased cell proliferation. These effects, which are reproducible in cells from multiple human donors, are mediated, at least in part, by AKT-FOXO1 signaling. ALK5 inhibition synergizes with a soluble factor cocktail to promote BCD cell redifferentiation. The combined treatment may offer a therapeutically applicable way for generating an abundant source of functional insulin-producing cells following ex-vivo expansion.

  1. Pancreatic islet amyloidosis, β-cell apoptosis, and α-cell proliferation are determinants of islet remodeling in type-2 diabetic baboons

    Science.gov (United States)

    Guardado-Mendoza, Rodolfo; Davalli, Alberto M.; Chavez, Alberto O.; Hubbard, Gene B.; Dick, Edward J.; Majluf-Cruz, Abraham; Tene-Perez, Carlos E.; Goldschmidt, Lukasz; Hart, John; Perego, Carla; Comuzzie, Anthony G.; Tejero, Maria Elizabeth; Finzi, Giovanna; Placidi, Claudia; La Rosa, Stefano; Capella, Carlo; Halff, Glenn; Gastaldelli, Amalia; DeFronzo, Ralph A.; Folli, Franco

    2009-01-01

    β-Cell dysfunction is an important factor in the development of hyperglycemia of type-2 diabetes mellitus, and pancreatic islet amyloidosis (IA) has been postulated to be one of the main contributors to impaired insulin secretion. The aim of this study was to evaluate the correlation of IA with metabolic parameters and its effect on islets of Langerhans remodeling and relative endocrine-cell volume in baboons. We sequenced the amylin peptide, determined the fibrillogenic propensities, and evaluated pancreatic histology, clinical and biochemical characteristics, and endocrine cell proliferation and apoptosis in 150 baboons with different metabolic status. Amylin sequence in the baboon was 92% similar to humans and showed superimposable fibrillogenic propensities. IA severity correlated with fasting plasma glucose (FPG) (r = 0.662, P < 0.001) and HbA1c (r = 0.726, P < 0.001), as well as with free fatty acid, glucagon values, decreased homeostasis model assessment (HOMA) insulin resistance, and HOMA-B. IA severity was associated with a decreased relative β-cell volume, and increased relative α-cell volume and hyperglucagonemia. These results strongly support the concept that IA and β-cell apoptosis in concert with α-cell proliferation and hypertrophy are key determinants of islets of Langerhans “dysfunctional remodeling” and hyperglycemia in the baboon, a nonhuman primate model of type-2 diabetes mellitus. The most important determinants of IA were age and FPG (R2 = 0.519, P < 0.0001), and different FPG levels were sensitive and specific to predict IA severity. Finally, a predictive model for islet amyloid severity was generated with age and FPG as required variables. PMID:19666551

  2. A stereological study of effects of aqueous extract of Tamarindus indica seeds on pancreatic islets in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Hamidreza, Hamidreza; Heidari, Zahra; Shahraki, Mohammadreza; Moudi, Bita

    2010-10-01

    Tamarindus indica Linn was used as a traditional medicine for the management of diabetes mellitus in human and experimental animals. This study investigated effects of aqueous extract of Tamarindus indica seeds (AETIS) against STZ-induced damages in pancreatic islands by means of stereological methods. sixty matured normoglycemic male Wistar rats, weighing 200-250 gr, were selected and randomly divided into 6 groups (n=10). Control, STZ-induced diabetic; by intraperitoneal injection of 55 mg/Kg streptozotocin, Treated control group (TC); received AETIS at a dose of 200mg/kg/day, and AETIS treated diabetic groups (TD1-3); received respectively AETIS at the dose of 50, 100,and 200 mg/kg/day by gavage from one week after induction of diabetes by STZ. After 8 weeks of experiment, stereological estimation of volume density and total volume of islets and beta cells, volume weighted mean islets volume, mass of beta cells, islets, and pancreas and total number of islets were done. Volume density and total volume of islets, volume weighted mean islets volume, volume density islets/pancreas, volume density beta cells/islet, mass of islets and pancreas of treated diabetic groups (TD1-3) were significantly higher than untreated diabetic group (P0.05). Total number of islets, pancreas wet weight and volume did not show any significant changes between control and experimental groups (P>0.05). Results suggested that AETIS partially restores pancreatic beta cells and repairs STZ-induced damages in rats.

  3. The Potential Protective Action of Vitamin D in Hepatic Insulin Resistance and Pancreatic Islet Dysfunction in Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Leung, Po Sing

    2016-03-01

    Vitamin D deficiency (i.e., hypovitaminosis D) is associated with increased insulin resistance, impaired insulin secretion, and poorly controlled glucose homeostasis, and thus is correlated with the risk of metabolic diseases, including type 2 diabetes mellitus (T2DM). The liver plays key roles in glucose and lipid metabolism, and its dysregulation leads to abnormalities in hepatic glucose output and triglyceride accumulation. Meanwhile, the pancreatic islets are constituted in large part by insulin-secreting β cells. Consequently, islet dysfunction, such as occurs in T2DM, produces hyperglycemia. In this review, we provide a critical appraisal of the modulatory actions of vitamin D in hepatic insulin sensitivity and islet insulin secretion, and we discuss the potential roles of a local vitamin D signaling in regulating hepatic and pancreatic islet functions. This information provides a scientific basis for establishing the benefits of the maintenance, or dietary manipulation, of adequate vitamin D status in the prevention and management of obesity-induced T2DM and non-alcoholic fatty liver disease. PMID:26959059

  4. Differentiation of fetal pancreatic stem cells into neuron-like and islet-like cells in vitro ★

    OpenAIRE

    Hua, Xiufeng; Wang, Yanwei; Lian, Peiwen; Zhang, Shouxin; Li, Jianyuan; Wang, Haiyan; Chen, Shulin; Gao, Wei

    2012-01-01

    Pancreatic stem cells were isolated and cultured from aborted human fetal pancreases of gestational age 14–20 weeks. They were seeded at a density of 1 × 104 in serum-free media for differentiation into neuron-like cells, expressing β-tubulin III and glial fibrillary acidic protein. These neuron-like cells displayed a synapse-like morphology and appeared to form a neuronal network. Pancreatic stem cells were also seeded at a density of 1 × 105 for differentiation into islet-like cells, expres...

  5. MicroRNAs: Novel Players in the Dialogue between Pancreatic Islets and Immune System in Autoimmune Diabetes

    OpenAIRE

    Giuliana Ventriglia; Laura Nigi; Guido Sebastiani; Francesco Dotta

    2015-01-01

    MicroRNAs are small noncoding RNA molecules that regulate gene expression in all cell types. Therefore, these tiny noncoding RNA molecules are involved in a wide range of biological processes, exerting functional effects at cellular, tissue, and organ level. In pancreatic islets of Langerhans, including beta-cells, microRNAs are involved in cell differentiation as well as in insulin secretion, while in immune cells they have been shown to play pivotal roles in development, activation, and res...

  6. Morphological Change in Pancreatic Islets, Insulin Binding and Intracellular Glucose Metabolism in Adipocytes of Streptozotocin-induced Diabetic Rats *

    OpenAIRE

    Cha, Bong Yun; Son, Ho Young; Min, Byong Sok; Kim, Hak Joong

    1987-01-01

    To examine the diabetogenic mechanism of streptozotocin, a histological study was performed on the pancreatic islets of male Wistar rats 7 days after an intravenous injection of streptozotocin (75 mg/kg). Furthermore, for the investigation into mechanism of insulin resistance in the insulin-dependent diabetic rats, insulin binding, glucose transport, and lipogenesis were studied in the isolated adipocytes of streptozotocin-induced diabetic rats. 1) The rate of weight gain in the control rats ...

  7. Improvement in The Function of Isolated Rat Pancreatic Islets through Reduction of Oxidative Stress Using Traditional Iranian Medicine

    Directory of Open Access Journals (Sweden)

    Mahban Rahimifard

    2014-06-01

    Full Text Available Objective: Pancreatic islets have fewer antioxidant enzymes than other tissues and thus are vulnerable to oxidative stress. In the present study, the effects of nine specifically selected Iranian medical plants on the mitochondria function and survival of isolated rat islets were examined. Materials and Methods: In this experimental study, following laparotomy, pancreases of rats were removed and the islets isolated and incubated in vitro for 24 hours. Logarithmic doses of plant materials were added to the islets and incubated for an additional 24 hours after which the viability of the cells and production of reactive oxygen species (ROS were measured. Levels of insulin production in relation to static and stimulated glucose concentrations were also determined. Results: The tested compounds markedly increased survival of the islet cells, their mitochondrial activity, and insulin levels at the same time as reducing production of ROS. Greatest effects were observed in the following order: Peganum harmala, Glycyrrhiza glabra, Satureja hortensis, Rosmarinus officinalis, Teucrium scordium, Aloe vera, Zingiber officinale, Silybum marianum, and Hypericum perforatum at doses of 10, 103, 104, 10, 102, 102, 10-1, 10 and 103 μgmL-1, respectively. Conclusion: Based on these results, we suggest that pretreatment with these selected Iranian medical plants can improve the outcomes of pancreas transplants and grafts through the control of oxidative stress damage.

  8. Inhibition of nuclear factor-κB activation in pancreatic β-cells has a protective effect on allogeneic pancreatic islet graft survival.

    Directory of Open Access Journals (Sweden)

    Roy Eldor

    Full Text Available Pancreatic islet transplantation, a treatment for type 1 diabetes, has met significant challenges, as a substantial fraction of the islet mass fails to engraft, partly due to death by apoptosis in the peri- and post-transplantation periods. Previous evidence has suggested that NF-κB activation is involved in cytokine-mediated β-cell apoptosis and regulates the expression of pro-inflammatory and chemokine genes. We therefore sought to explore the effects of β-cell-specific inhibition of NF-κB activation as a means of cytoprotection in an allogeneic model of islet transplantation. To this end, we used islets isolated from the ToI-β transgenic mouse, where NF-κB signalling can specifically and conditionally be inhibited in β-cells by expressing an inducible and non-degradable form of IκBα regulated by the tet-on system. Our results show that β-cell-specific blockade of NF-κB led to a prolonged islet graft survival, with a relative higher preservation of the engrafted endocrine tissue and reduced inflammation. Importantly, a longer delay in allograft rejection was achieved when mice were systemically treated with the proteasome inhibitor, Bortezomib. Our findings emphasize the contribution of NF-κB activation in the allograft rejection process, and suggest an involvement of the CXCL10/IP-10 chemokine. Furthermore, we suggest a potential, readily available therapeutic agent that may temper this process.

  9. Effect of total lymphoid irradiation and pretransplant blood transfusion on pancreatic islet allograft survival

    International Nuclear Information System (INIS)

    Total lymphoid irradiation (TLI) has been shown to have a strong immunosuppressive effect both experimentally and clinically. Pretransplant blood transfusions have also been shown to have a strong beneficial effect in the outcome of organ transplantation. A study was made of the effect of TLI and pretransplant blood transfusions, alone and in combination, as an immunosuppressive modality in the isolated pancreatic islet transplant in the rat model. Donor rats (Fischer RT1v1) were kept on a 50% DL-ethionine supplemented diet for 4-6 weeks prior to pancreas removal. Recipient rats (Lewis RT1) were made diabetics prior to transplantation by iv injection of streptozotocin (45 mg/kg). Transfusion protocol consisted of a biweekly transfusion of 2 ml of either donor specific or third party transfusions. Total lymphoid irradiation was carried out by daily administration of 200 rads during one week prior to transplantation. Transplantation of the isolated islets was performed by intraportal injection. Syngeneic transplant of one and a half donor pancreata in each recipient reverted the diabetic condition indefinitely (greater than 100 days). Untreated allogenic grafts had a mean survival time (MST) of 5.2 days. Total lymphoid irradiation in dosages of 800, 1000, and 1200 rads, as the only immunosuppressive regimen, prolonged the MST of allografts to 15.3, 16.5, and 21.8 days, respectively (P less than .05). Pretransplant third party blood transfusion had no effect on allograft survival (MST 6.0). When donor specific blood transfusions were given, the MST was prolonged to 25.3 days (P less than .05). When TLI was administered to recipients of donor specific transfusions, the MST of the allografts did not show any statistical significant difference when compared with untreated animals. This abrogation of the beneficial effect of specific blood transfusion was observed in all dosages of TLI employed: 800 rad (MST 3.0), 1000 rad (MST 8.0), 1200 rad (MST 5.18)

  10. Immunosuppression, macroencapsulation and ultraviolet-B irradiation as immunoprotection in porcine pancreatic islet xenotransplantation

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, J.O.; Olsson, N.; Hellerstroem, C.; Andersson, A. [Uppsala Univerity, Dept. of Medical Cell Biology, Uppsala (Sweden); Johnson, R.C. [Baxter Healthcar Corporation, Gene Therapy Unit, Illinois (United States)

    1995-09-01

    Membrane encapsulation or ultraviolet-B irradiation, with or without mild immunosuppressive treatment, was applied in order to prolong the survival of xenogeneic porcine foetal pancreatic grafts. Non-diabetic C57BL/6 mice were transplanted with porcine islet-like cell clusters, either membrane-encapsulated in the epididymal fat pad, or non-encapsulated under the kidney capsule. The animals were treated with daily subcutaneous injections of either cyclosporin A (12.5 mg/kg b.wt.), 15-deoxyspergualin (5.0 mg/kg b.wt.), ethyl (E)-6-(1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxo-6-isobenzofurany l-4-methyl-4-hexenoate). (RS-61443) (70 mg/kg b.wt.) or with cyclophosphamide (70 mg/kg b.wt.) every second day. A fulminant mononuclear cell infiltration was observed 14 days after transplantation both around the subcapsular graft and outside the membranes in the saline treated control group. The membrane had pores of 0.45 {mu}m and was designed to allow macromolecule transport but prevents cells from crossing. Therefore, xenoantigens can escape from the membrane implants and cause an immune reaction. A significantly weaker mononuclear cell infiltration was, however, seen when the membrane barrier was combined with 15-deoxyspergualin, cyclophosphamide or RS-61443 treatment but the morphology of the encapsulated ICC was not improved. The best subcapsular, non-encapsulated graft survival was obtained in animals treated with 15-deoxyspergualin or cyclophosphamide and the graft insulin content measurements confirmed the morphological data. There was no prolongation of islet-like cell cluster graft survival under the kidney capsule after ultraviolet-B irradiation alone (650 J/m{sup 2} for 90 sec.), and no synergistic effect was observed. It is concluded that neither membrane encapsulation with membrane that allow xenoantigen escape from the implants nor ultraviolet-B irradiation are able to prolong discordant xenograft survival in mice. (Abstract Truncated)

  11. Damage to pancreatic acinar cells and preservation of islets of Langerhans in a rat model of acute pancreatitis induced by Karwinskia humboldtiana (buckthorn).

    Science.gov (United States)

    Carcano-Diaz, Katya; Garcia-Garcia, Aracely; Segoviano-Ramirez, Juan Carlos; Rodriguez-Rocha, Humberto; Loera-Arias, Maria de Jesus; Garcia-Juarez, Jaime

    2016-09-01

    Karwinskia humboldtiana (Kh) is a poisonous plant that grows in some regions of the American continent. Consuming large amounts of Kh fruit results in acute intoxication leading to respiratory failure, culminating in death within days. There is evidence of histological damage to the lungs, liver, and kidneys following accidental and experimental Kh intoxication. To date, the microscopic effect of Kh consumption on the pancreas has not been described. We examined the early effects of Kh fruit on pancreatic tissue at different stages of acute intoxication in the Wistar rat. We found progressive damage confined to the exocrine pancreas, starting with a reduction in the number of zymogen granules, loss of acinar architecture, the presence of autophagy-like vesicles, apoptosis and inflammatory infiltrate. The pancreatic pathology culminated in damaged acini characterized by necrosis and edema, with a complete loss of lobular architecture. Interestingly, the morphology of the islets of Langerhans was conserved throughout our evaluations. Taken together, our results indicate the damage induced by a high dose of Kh fruit in the Wistar rat is consistent with an early acute necrotizing pancreatitis that exclusively affects the exocrine pancreas. Therefore, this system might be useful as an animal model to study the treatment of pancreatic diseases. More importantly, as the islets of Langerhans were preserved, the active compounds of Kh fruit could be utilized for the treatment of acinar pancreatic cancer. Further studies might provide insight into the severity of acute Kh intoxication in humans and influence the design of treatments for pancreatic diseases and acinar pancreatic cancer. PMID:26877198

  12. Exocrine contamination impairs implantation of pancreatic islets transplanted beneath the kidney capsule.

    Science.gov (United States)

    Gray, D W; Sutton, R; McShane, P; Peters, M; Morris, P J

    1988-11-01

    The effect of exocrine contamination on islets implanted under the kidney capsule has been studied by histological examination of pure or exocrine-contamination human, monkey, or rat islets transplanted to the kidney capsule of the nude rat, monkey, or rat, respectively. Exocrine contamination resulted in an appearance suggestive of impaired islet implantation, due to tissue necrosis and subsequent fibrosis. The effect of exocrine contamination was examined quantitatively in a rat islet isograft model in which handpicked DA rat islets were transplanted under the kidney capsule of normal DA rats. The islets were either pure or deliberately recontaminated with exocrine tissue (50 or 90% contamination). Four hundred pure islets were placed under one kidney capsule and 400 islets (of similar size and from the same islet preparation) were contaminated and then placed under the contralateral kidney capsule. After 2 weeks the kidneys were removed and extracted for insulin content. The insulin content of kidneys bearing islets contaminated by either 50 or 90% exocrine tissue was significantly reduced when compared to the contralateral kidney bearing pure islets. These findings support the view that exocrine contamination of islets resulted in impaired islet implantation when transplanted to a confined site such as the kidney subcapsule.

  13. 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.

  14. Expression of PDX-1 is reduced in pancreatic islets from pups of rat dams fed a low protein diet during gestation and lactation.

    Science.gov (United States)

    Arantes, Vanessa C; Teixeira, Vicente P A; Reis, Marise A B; Latorraca, Márcia Q; Leite, Adriana R; Carneiro, Everardo M; Yamada, Aureo T; Boschero, Antonio C

    2002-10-01

    Intrauterine and early postnatal malnutrition has profound consequences on fetal and postnatal development in both humans and animals. In addition, low birth weight has been reported to be associated with impaired insulin secretion, insulin resistance and diminished area of pancreatic islets. Because the transcription factor pancreatic and duodenal homeobox 1 (PDX-1) is important for the maintenance of B-cell physiology, PDX-1 expression and islet area were assessed in neonatal rats of dams fed low (6%) or normal (17%) protein diets during pregnancy. PDX-1 protein and mRNA levels, as well as insulin secretion and islet area, were measured after 28 d of life in normal, low protein and recovered rats whose dams consumed a normal protein diet after delivery. Insulin secretion by isolated islets in response to 2.8 and 16.7 mmol glucose/L was reduced in 28-d-old low protein rats compared with the control (P < 0.05). At birth and after 28 d of life, the islet area and PDX-1 protein expression were also reduced (P < 0.05). In contrast, PDX-1 mRNA levels in islets from 28-d-old low protein rats were not different from control rats. PDX-1 protein expression in pancreatic islets, the area of islets and insulin secretion were restored in recovered rats, whereas PDX-1 mRNA levels were higher than in normal rats (P < 0.05). These results suggest a link among diminished PDX-1 protein expression, a reduction in islet area and impaired insulin secretion in low protein rats. The reintroduction of a normal diet early in life restored islet area and cell physiology. PMID:12368391

  15. Synergistic Potentials of Coffee on Injured Pancreatic Islets and Insulin Action via KATP Channel Blocking in Zebrafish.

    Science.gov (United States)

    Nam, Youn Hee; Hong, Bin Na; Rodriguez, Isabel; Ji, Min Gun; Kim, Keonwoo; Kim, Ung-Jin; Kang, Tong Ho

    2015-06-17

    Pancreatic islets (PIs) are damaged under diabetic conditions, resulting in decreased PI size. This study examined the regenerative effects of coffee and its components (caffeine, CFI; trigonelline, TRG; chlorogenic acid, CGA) on zebrafish larval PIs and β-cells damaged by administration of alloxan (AX). In addition, the influence of coffee and its active components on KATP channels was investigated using diazoxide (DZ) as a KATP channel activator. PI size and fluorescence intensity were significantly increased in the coffee-treated group relative to the no-treatment group (P coffee exerted significant regenerative effects on pancreatic β-cells (p = 0.006). Treatment with TRG and CGA rescued PI damage, and the combination of TRG/CGA had a synergistic effect. In conclusion, the results indicate that coffee has beneficial effects on AX-damaged PIs and may also be useful as a blocker of pancreatic β-cell K(+) channels.

  16. Facilitating effects of berberine on rat pancreatic islets through modulating hepatic nuclear factor 4 alpha expression and glucokinase activity

    Institute of Scientific and Technical Information of China (English)

    Zhi-Quan Wang; Fu-Er Lu; San-Hua Leng; Xin-Sheng Fang; Guang Chen; Zeng-Si Wang; Li-Ping Dong; Zhong-Qing Yan

    2008-01-01

    AIM: To observe the effect of berberine on insulin secretion in rat pancreatic islets and to explore its possible molecular mechanism.METHODS: Primary rat islets were isolated from male Sprague-Dawley rats by collagenase digestion and treated with different concentrations (1, 3, 10 and 30 μmol/L) of berberine or 1 μmol/L Glibenclamide (GB) for 24 h. Glucose-stimulated insulin secretion (GSIS) assay was conducted and insulin was determined by radioimmunoassay. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (NTT) assay was performed to evaluate cytotoxicity. The mRNA level of hepatic nuclear factor 4 alpha (HNF4α) was determined by reverse transcription polymerase chain reaction (RT-PCR). Indirect immunofluorescence staining and Western blot analysis were employed to detect protein expression of HNF4α in the islets. Glucokinase (GK) activity was measured by spectrophotometric method.RESULTS: Berberine enhanced GSIS rather than basal insulin secretion dose-dependently in rat islets and showed no significant cytotoxicity on islet cells at the concentration of 10 μmol/L. Both mRNA and protein expressions of HNF4α were up-regulated by berberine in a dose-dependent manner, and GK activity was also increased accordingly. However, GB demonstrated no regulatory effects on HNF4α expression or GK activity.CONCLUSION: Berberine can enhance GSIS in rat islets, and probably exerts the insulinotropic effect via a pathway involving HNF4α and GK, which is distinct from sulphonylureas (SUs).

  17. Hyperglycemia downregulates Connexin36 in pancreatic islets via the upregulation of ICER-1/ICER-1γ.

    Science.gov (United States)

    Haefliger, Jacques-Antoine; Rohner-Jeanrenaud, Françoise; Caille, Dorothée; Charollais, Anne; Meda, Paolo; Allagnat, Florent

    2013-01-01

    Channels formed by the gap junction protein Connexin36 (CX36) contribute to the proper control of insulin secretion. We previously demonstrated that chronic exposure to glucose decreases Cx36 levels in insulin-secreting cells in vitro. Here, we investigated whether hyperglycemia also regulates Cx36 in vivo. Using a model of continuous glucose infusion in adult rats, we showed that prolonged (24-48 h) hyperglycemia reduced the Cx36 gene Gjd2 mRNA levels in pancreatic islets. Accordingly, prolonged exposure to high glucose concentrations also reduced the expression and function of Cx36 in the rat insulin-producing INS-1E cell line. The glucose effect was blocked after inhibition of the cAMP/PKA pathway and was associated with an overexpression of the inducible cAMP early repressor ICER-1/ICER-1γ, which binds to a functional cAMP-response element in the promoter of the Cx36 gene Gjd2. The involvement of this repressor was further demonstrated using an antisense strategy of ICER-1 inhibition, which prevented glucose-induced downregulation of Cx36. The data indicate that chronic exposure to glucose alters the in vivo expression of Cx36 by the insulin-producing β-cells through ICER-1/ICER-1γ overexpression. This mechanism may contribute to the reduced glucose sensitivity and altered insulin secretion, which contribute to the pathophysiology of diabetes. PMID:23613279

  18. Glucose decouples intracellular Ca2+ activity from glucagon secretion in mouse pancreatic islet alpha-cells.

    Directory of Open Access Journals (Sweden)

    Sylvain J Le Marchand

    Full Text Available The mechanisms of glucagon secretion and its suppression by glucose are presently unknown. This study investigates the relationship between intracellular calcium levels ([Ca(2+](i and hormone secretion under low and high glucose conditions. We examined the effects of modulating ion channel activities on [Ca(2+](i and hormone secretion from ex vivo mouse pancreatic islets. Glucagon-secreting α-cells were unambiguously identified by cell specific expression of fluorescent proteins. We found that activation of L-type voltage-gated calcium channels is critical for α-cell calcium oscillations and glucagon secretion at low glucose levels. Calcium channel activation depends on K(ATP channel activity but not on tetrodotoxin-sensitive Na(+ channels. The use of glucagon secretagogues reveals a positive correlation between α-cell [Ca(2+](i and secretion at low glucose levels. Glucose elevation suppresses glucagon secretion even after treatment with secretagogues. Importantly, this inhibition is not mediated by K(ATP channel activity or reduction in α-cell [Ca(2+](i. Our results demonstrate that glucose uncouples the positive relationship between [Ca(2+](i and secretory activity. We conclude that glucose suppression of glucagon secretion is not mediated by inactivation of calcium channels, but instead, it requires a calcium-independent inhibitory pathway.

  19. Functional proteomics screen enables enrichment of distinct cell types from human pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Revital Sharivkin

    Full Text Available The current world-wide epidemic of diabetes has prompted attempts to generate new sources of insulin-producing cells for cell replacement therapy. An inherent challenge in many of these strategies is the lack of cell-surface markers permitting isolation and characterization of specific cell types from differentiating stem cell populations. Here we introduce an iterative proteomics procedure allowing tag-free isolation of cell types based on their function. Our method detects and associates specific cell-surface markers with particular cell functionality by coupling cell capture on antibody arrays with immunofluorescent labeling. Using this approach in an iterative manner, we discovered marker combinations capable of enriching for discrete pancreatic cell subtypes from human islets of Langerhans: insulin-producing beta cells (CD9high/CD56+, glucagon-producing alpha cells (CD9-/CD56+ and trypsin-producing acinar cells (CD9-/CD56-. This strategy may assist future beta cell research and the development of diagnostic tools for diabetes. It can also be applied more generally for function-based purification of desired cell types from other limited and heterogeneous biological samples.

  20. Vanadyl Sulfate Treatment Stimulates Proliferation and Regeneration of Beta Cells in Pancreatic Islets

    Directory of Open Access Journals (Sweden)

    Samira Missaoui

    2014-01-01

    Full Text Available We examined the effects of vanadium sulfate (VOSO4 treatment at 5 and 10 mg/kg for 30 days on endocrine pancreas activity and histology in nondiabetic and STZ-induced diabetic rats. In diabetic group, blood glucose levels significantly increased while insulinemia level markedly decreased. At the end of treatment, VOSO4 at a dose of 10 mg/Kg normalized blood glucose level in diabetic group, restored insulinemia, and significantly improved insulin sensitivity. VOSO4 also increased in a dose-dependent manner the number of insulin immunopositive beta cells in pancreatic islets of nondiabetic rats. Furthermore, in the STZ-diabetic group, the decrease in the number of insulin immunopositive beta cells was corrected to reach the control level mainly with the higher dose of vanadium. Therefore, VOSO4 treatment normalized plasma glucose and insulin levels and improved insulin sensitivity in STZ-experimental diabetes and induced beta cells proliferation and/or regeneration in normal or diabetic rats.

  1. Islet-selectivity of G-protein coupled receptor ligands evaluated for PET imaging of pancreatic {beta}-cell mass

    Energy Technology Data Exchange (ETDEWEB)

    Cline, Gary W., E-mail: gary.cline@yale.edu [Yale University School of Medicine (United States); Zhao, Xiaojian [Yale University School of Medicine (United States); Jakowski, Amy B.; Soeller, Walter C.; Treadway, Judith L. [Pfizer Global Research and Development, Pfizer Inc., Groton CT (United States)

    2011-09-02

    Highlights: {yields} We screened G-protein coupled receptors for imaging pancreatic. {yields} Database mining and immunohistochemistry identified GPCRs enriched in {beta}-cells. {yields} In vitro and in vivo assays were used to determine exocrine vs endocrine specificity. {yields} GPCR candidates for imaging of {beta}-cell mass are Prokineticin-1R, mGluR5, and GLP-1R. -- Abstract: A critical unmet need exists for methods to quantitatively measure endogenous pancreatic {beta}-cell mass (BCM) for the clinical evaluation of therapies to prevent or reverse loss of BCM and diabetes progression. Our objective was to identify G-protein coupled receptors (GPCRs) that are expressed with a high degree of specificity to islet {beta}-cells for receptor-targeted imaging of BCM. GPCRs enriched in pancreatic islets relative to pancreas acinar and hepatic tissue were identified using a database screen. Islet-specific expression was confirmed by human pancreas immunohistochemistry (IHC). In vitro selectivity assessment was determined from the binding and uptake of radiolabeled ligands to the rat insulinoma INS-1 832/13 cell line and isolated rat islets relative to the exocrine pancreas cell-type, PANC-1. Tail-vein injections of radioligands into rats were used to determine favorable image criteria of in vivo biodistribution to the pancreas relative to other internal organs (i.e., liver, spleen, stomach, and lungs). Database and IHC screening identified four candidate receptors for further in vitro and in vivo evaluation for PET imaging of BCM: prokineticin-1 receptor (PK-1R), metabotropic glutamate receptor type-5 (mGluR5), neuropeptide Y-2 receptor (NPY-2R), and glucagon-like peptide 1 receptor (GLP-1R). In vitro specificity ratios gave the following receptor rank order: PK-1R > GLP-1R > NPY-2R > mGluR5. The biodistribution rank order of selectivity to the pancreas was found to be PK-1R > VMAT2 {approx} GLP-1R > mGluR5. Favorable islet selectivity and biodistribution

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Quantitative analysis of cell composition and purity of human pancreatic islet preparations.

    Science.gov (United States)

    Pisania, Anna; Weir, Gordon C; O'Neil, John J; Omer, Abdulkadir; Tchipashvili, Vaja; Lei, Ji; Colton, Clark K; Bonner-Weir, Susan

    2010-11-01

    Despite improvements in outcomes for human islet transplantation, characterization of islet preparations remains poorly defined. This study used both light microscopy (LM) and electron microscopy (EM) to characterize 33 islet preparations used for clinical transplants. EM allowed an accurate identification and quantification of cell types with measured cell number fractions (mean±s.e.m.) of 35.6±2.1% β-cells, 12.6±1.0% non-β-islet cells (48.3±2.6% total islet cells), 22.7±1.5% duct cells, and 25.3±1.8% acinar cells. Of the islet cells, 73.6±1.7% were β-cells. For comparison with the literature, estimates of cell number fraction, cell volume, and extracellular volume were combined to convert number fraction data to volume fractions applicable to cells, islets, and the entire preparation. The mathematical framework for this conversion was developed. By volume, β-cells were 86.5±1.1% of the total islet cell volume and 61.2±0.8% of intact islets (including the extracellular volume), which is similar to that of islets in the pancreas. Our estimates produced 1560±20 cells in an islet equivalent (volume of 150-μm diameter sphere), of which 1140±15 were β-cells. To test whether LM analysis of the same tissue samples could provide reasonable estimates of purity of the islet preparations, volume fraction of the islet tissue was measured on thin sections available from 27 of the clinical preparations by point counting morphometrics. Islet purity (islet volume fraction) of individual preparations determined by LM and EM analyses correlated linearly with excellent agreement (R²=0.95). However, islet purity by conventional dithizone staining was substantially higher with a 20-30% overestimation. Thus, both EM and LM provide accurate methods to determine the cell composition of human islet preparations and can help us understand many of the discrepancies of islet composition in the literature. PMID:20697378

  4. Leptin Regulated Insulin Secretion via Stimulating IRS2-associated Phosphoinositide 3-kinase Activity in the isolated Rat Pancreatic Islets

    Institute of Scientific and Technical Information of China (English)

    袁莉; 安汉祥; 李卓娅; 邓秀玲

    2003-01-01

    To investigate the molecular mechanism of leptin regulating insulin secretion through determining the regulation of insulin secretion and the insulin receptor substrate (IRS)-2-associated phosphoinositide 3-kinase (PI3K) activity by leptin in the isolated rat pancreatic islets, pancreatic islets were isolated from male SD rats by the collagenase method. The purified islets were incubated with leptin 2 nmol/L for 1 h in the presence of 5.6 mmol/L or 11.1 mmol/L glucose. Insulin release was measured using radioimmunoassay. IRS-2-associated activity of PI3K was determined by immunoprecipitate assay and Western blot. The results showed that in the presence of 5.6 mmol/L glucose, leptin had no significant effect on both insulin secretion and IRS-2-associated PI3K activity, but in the presence of 11.1 mmol/L glucose, insulin release was significantly inhibited after the islets were exposed to leptin for 1 h (P<0. 01). PI3K inhibitor wortmannin blocked the inhibitory regulation of leptin on insulin release (P<0. 05). Western Blot assay revealed that 2 nmol/L leptin could significantly increase the IRS-2-associated activity of PI3K by 51.5 % (P<0. 05) in the presence of 11.1 mmol/L glucose. It was concluded that Leptin could significantly inhibit insulin secretion in the presence of 11.1 mmol/L glucose by stimulating IRS-2-associated activity of PI3K, which might be the molecular mechanism of leptin regulating insulin secretion.

  5. What difference exists in the pancreas of mammals with sanguivorous diet? A morphological, stereological and immunohistochemical study of the pancreatic islets of the hematophagous bat Diphylla ecaudata.

    Science.gov (United States)

    Machado-Santos, Clarice; Aquino, Júlio César Fraulob; Mikalauka, Jefferson Simanas; Abidu-Figueiredo, Marcelo; Mendes, Rosa Maria Marcos; Sales, Armando

    2013-05-10

    Diphylla ecaudata is a vampire bat that mainly feeds on the blood of birds. This highly specialized diet - hematophagy - is accompanied by a series of morphological changes in the gastro-entero-pancreatic system, since the distribution and relative proportions of different pancreatic endocrine cell types can vary between species due to different physiological conditions and eating habits. The aim of this study was to examine for the first time the pancreas of the vampire bat D. ecaudata using morphological, stereological and immunohistochemical techniques. The pancreas of the D. ecaudata has an exocrine acinar portion in which the highest concentration of pancreatic islets is scattered. These pancreatic islets have irregular size and a mean diameter of 56.94 μm. The total number of islets in the pancreas was 23,900, with a volumetric density of 4.1%. Insulin-immunoreactive (IR) cells were located in the central pancreatic islet region and had the largest density (54.8%). Glucagon-IR cells were located mainly in the peripheral mantle region (16.2%), along with somatostatin-IR (SS) cells (14.3%). Cells immunoreactive to insulin, glucagon and somatostatin were also observed to have spread in isolated places in the exocrine pancreas. In the connective tissue near the pancreatic ducts, a high concentration was identified of insulin-IR cells and a low concentration of glucagon-IR and somatostatin-IR cells. These results indicate that although the pancreas of D. ecaudata has morphological similarities with that of other mammals, it has a differentiated islet structure, because there were a large number of islets and different volumetric densities of α, β and δ cells. PMID:23500834

  6. 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.

  7. Trefoil factor 3 stimulates human and rodent pancreatic islet beta-cell replication with retention of function.

    Science.gov (United States)

    Fueger, Patrick T; Schisler, Jonathan C; Lu, Danhong; Babu, Daniella A; Mirmira, Raghavendra G; Newgard, Christopher B; Hohmeier, Hans E

    2008-05-01

    Both major forms of diabetes involve a decline in beta-cell mass, mediated by autoimmune destruction of insulin-producing cells in type 1 diabetes and by increased rates of apoptosis secondary to metabolic stress in type 2 diabetes. Methods for controlled expansion of beta-cell mass are currently not available but would have great potential utility for treatment of these diseases. In the current study, we demonstrate that overexpression of trefoil factor 3 (TFF3) in rat pancreatic islets results in a 4- to 5-fold increase in [(3)H]thymidine incorporation, with full retention of glucose-stimulated insulin secretion. This increase was almost exclusively due to stimulation of beta-cell replication, as demonstrated by studies of bromodeoxyuridine incorporation and co-immunofluorescence analysis with anti-bromodeoxyuridine and antiinsulin or antiglucagon antibodies. The proliferative effect of TFF3 required the presence of serum or 0.5 ng/ml epidermal growth factor. The ability of TFF3 overexpression to stimulate proliferation of rat islets in serum was abolished by the addition of epidermal growth factor receptor antagonist AG1478. Furthermore, TFF3-induced increases in [3H]thymidine incorporation in rat islets cultured in serum was blocked by overexpression of a dominant-negative Akt protein or treatment with triciribine, an Akt inhibitor. Finally, overexpression of TFF3 also caused a doubling of [3H]thymidine incorporation in human islets. In summary, our findings reveal a novel TFF3-mediated pathway for stimulation of beta-cell replication that could ultimately be exploited for expansion or preservation of islet beta-cell mass.

  8. Studies on alterations of the 86-rubidium efflux from rat pancreatic islets caused by thiol and thiol oxidants

    International Nuclear Information System (INIS)

    The following findings were revealed by this study: 1) Oxidation-reduction (redox) of the intracellular system of glutathione influences the potassium efflux by way of an increase in the 86-rubidium efflux brought about by the oxidation of intracellular thiols. 2) The 86-rubidium efflux is not subject to change by oxidation of extracellular thiols located in the membrane, nor can it in any way be influenced by reduced glutathione of exogenous origin. 3) The potassium efflux from rat pancreatic islets, being generally known to trigger the electric activities of the beta-cell, is controlled by the oxidation-reduction of intracellular thiols rather than by that of extracellular thiols. (TRV)

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

    DEFF Research Database (Denmark)

    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...... on the glucose-stimulated insulin release probably by increasing the glucose sensitivity. The results suggest that the alterations in glucose and insulin metabolism in pregnancy and during treatment with certain oral contraceptives may in part be due to a direct effect of progestins on the beta-cell....

  10. Pancreatic islet-specific T-cell clones from nonobese diabetic mice.

    OpenAIRE

    Haskins, K; Portas, M; Bergman, B.; Lafferty, K; Bradley, B

    1989-01-01

    We have produced a panel of islet-specific T-cell clones from nonobese diabetic (NOD) mice. These clones proliferate and make interleukin 2 in an antigen-specific manner in response to NOD antigen-presenting cells and islet cells. Most of the clones respond to islet-cell antigen from different mouse strains but only in the presence of antigen-presenting cells bearing the class II major histocompatibility complex of the NOD mouse. In vivo, the clones mediate the destruction of islet, but not p...

  11. Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications.

    Science.gov (United States)

    Gao, Bin; Wang, Lin; Han, Shuang; Pingguan-Murphy, Belinda; Zhang, Xiaohui; Xu, Feng

    2016-08-01

    Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.

  12. Impact of Pancreatic Rat Islet Density on Cell Survival during Hypoxia

    Directory of Open Access Journals (Sweden)

    A. Rodriguez-Brotons

    2016-01-01

    Full Text Available In bioartificial pancreases (BP, the number of islets needed to restore normoglycaemia in the diabetic patient is critical. However, the confinement of a high quantity of islets in a limited space may impact islet survival, particularly in regard to the low oxygen partial pressure (PO2 in such environments. The aim of the present study was to evaluate the impact of islet number in a confined space under hypoxia on cell survival. Rat islets were seeded at three different concentrations (150, 300, and 600 Islet Equivalents (IEQ/cm2 and cultured in normal atmospheric pressure (160 mmHg as well as hypoxic conditions (15 mmHg for 24 hours. Cell viability, function, hypoxia-induced changes in gene expression, and cytokine secretion were then assessed. Notably, hypoxia appeared to induce a decrease in viability and increasing islet density exacerbated the observed increase in cellular apoptosis as well as the loss of function. These changes were also associated with an increase in inflammatory gene transcription. Taken together, these data indicate that when a high number of islets are confined to a small space under hypoxia, cell viability and function are significantly impacted. Thus, in order to improve islet survival in this environment during transplantation, oxygenation is of critical importance.

  13. Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications.

    Science.gov (United States)

    Gao, Bin; Wang, Lin; Han, Shuang; Pingguan-Murphy, Belinda; Zhang, Xiaohui; Xu, Feng

    2016-08-01

    Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation. PMID:25669871

  14. Co-transplantation of endothelial progenitor cells and pancreatic islets to induce long-lasting normoglycemia in streptozotocin-treated diabetic rats.

    Science.gov (United States)

    Quaranta, Paola; Antonini, Sara; Spiga, Saturnino; Mazzanti, Benedetta; Curcio, Michele; Mulas, Giovanna; Diana, Marco; Marzola, Pasquina; Mosca, Franco; Longoni, Biancamaria

    2014-01-01

    Graft vascularization is a crucial step to obtain stable normoglycemia in pancreatic islet transplantation. Endothelial progenitor cells (EPCs) contribute to neoangiogenesis and to the revascularization process during ischaemic events and play a key role in the response to pancreatic islet injury. In this work we co-transplanted EPCs and islets in the portal vein of chemically-induced diabetic rats to restore islet vascularization and to improve graft survival. Syngenic islets were transplanted, either alone or with EPCs derived from green fluorescent protein (GFP) transgenic rats, into the portal vein of streptozotocin-induced diabetic rats. Blood glucose levels were monitored and intraperitoneal glucose tolerance tests were performed. Real time-PCR was carried out to evaluate the gene expression of angiogenic factors. Diabetic-induced rats showed long-lasting (6 months) normoglycemia upon co-transplantation of syngenic islets and EPCs. After 3-5 days from transplantation, hyperglycaemic levels dropped to normal values and lasted unmodified as long as they were checked. Further, glucose tolerance tests revealed the animals' ability to produce insulin on-demand as indexed by a prompt response in blood glucose clearance. Graft neovascularization was evaluated by immunohistochemistry: for the first time the measure of endothelial thickness revealed a donor-EPC-related neovascularization supporting viable islets up to six months after transplant. Our results highlight the importance of a newly formed viable vascular network together with pancreatic islets to provide de novo adequate supply in order to obtain enduring normoglycemia and prevent diabetes-related long-term health hazards. PMID:24733186

  15. Co-transplantation of endothelial progenitor cells and pancreatic islets to induce long-lasting normoglycemia in streptozotocin-treated diabetic rats.

    Directory of Open Access Journals (Sweden)

    Paola Quaranta

    Full Text Available Graft vascularization is a crucial step to obtain stable normoglycemia in pancreatic islet transplantation. Endothelial progenitor cells (EPCs contribute to neoangiogenesis and to the revascularization process during ischaemic events and play a key role in the response to pancreatic islet injury. In this work we co-transplanted EPCs and islets in the portal vein of chemically-induced diabetic rats to restore islet vascularization and to improve graft survival. Syngenic islets were transplanted, either alone or with EPCs derived from green fluorescent protein (GFP transgenic rats, into the portal vein of streptozotocin-induced diabetic rats. Blood glucose levels were monitored and intraperitoneal glucose tolerance tests were performed. Real time-PCR was carried out to evaluate the gene expression of angiogenic factors. Diabetic-induced rats showed long-lasting (6 months normoglycemia upon co-transplantation of syngenic islets and EPCs. After 3-5 days from transplantation, hyperglycaemic levels dropped to normal values and lasted unmodified as long as they were checked. Further, glucose tolerance tests revealed the animals' ability to produce insulin on-demand as indexed by a prompt response in blood glucose clearance. Graft neovascularization was evaluated by immunohistochemistry: for the first time the measure of endothelial thickness revealed a donor-EPC-related neovascularization supporting viable islets up to six months after transplant. Our results highlight the importance of a newly formed viable vascular network together with pancreatic islets to provide de novo adequate supply in order to obtain enduring normoglycemia and prevent diabetes-related long-term health hazards.

  16. Comparison of therapeutic characteristics of islet cell transplantation simultaneous with pancreatic mesenchymal stem cell transplantation in rats with Type 1 diabetes mellitus.

    Science.gov (United States)

    Unsal, Ilknur Ozturk; Ginis, Zeynep; Pinarli, Ferda Alparslan; Albayrak, Aynur; Cakal, Erman; Sahin, Mustafa; Delibasi, Tuncay

    2015-06-01

    Although, pancreas islet call transplantation is a new, promising method for type 1 diabetic patients, it remains as an experimental procedure applied in selected patients. The present study aimed to investigate effect of pancreatic mesenchymal stem cell transplantation simultaneous with islet cell transplantation on islet liveliness and thus on the treatment of diabetes in type 1 diabetic rats. The study used Wistar Albino Rats and was performed in a total of four groups [control (G1), mesenchymal stem cell (G2), islet (G3) and islet + mesencymal stem cell (G4)] each including 8 rats. Blood glucose level of the rats, in which diabetes model has been created using streptozotocin, was measured after 72 h. Blood samples were obtained from the rats 30 days after transplantation and then, their livers and pancreases were kept in 10% formaldehyde and the experiment was ended. Following staining with H&E, they were morphologically evaluated under a light microscope. Change in mean blood glucose level was statistically significant in G3 and G4 versus G1 and G2 (p = 0.001, p cells in the pancreases of the rats was higher in G4; difference between the groups was statistically significant (p cells together with mesenchymal stem cells showed beneficial effects in terms of prolonging survival of islet grafts suggesting that transplantation of mesenchymal stem cells together with islet cells during clinical islet transplantation may be beneficial in increasing the number of noninsulin-dependent patients in Type 1 diabetes.

  17. ISLET FORMATION AND REGENERATION

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective To explore the mechanisms of differentiation and development of pancreatic endocrine cells as well as pancreatic regeneration. Methods Human embryonic pancreatic tissue at 7-14 weeks of gestation was collected. Diabetes mellitus rat model was induced with 65 mg/kg of streptozotocin. Insulin, glucagon, somatostatin, nestin, and cytokeratin 19 (CK19)of pancreatic tissues were observed by immunohistochemistry. Results At 9 weeks of gestation, pancreatic epithelial cells began to co-express insulin, glucagon, somatostatin, and CK19 before migration. Islet cells gradually congregated along with the increase of aging, and at 14 weeks of gestation histological examination showed islet formation. At 12 weeks of gestation, nestin-positive cells could be seen in the pancreatic mesenchyme. During early embryogenesis, islet cells of pancreatic ducts co-expressed insulin, glucagon, and somatostatin. During pancreatic regeneration after damage, nestin expression of islet cells increased. Conclusion In the early stage of embryogenesis, islet cells of primary pancreatic ducts can be differentiated to multipotential endocrine cells before migration. During tissue regeneration, pancreatic stem cells may differentiate and proliferate to form pancreatic islet.

  18. Characterization of the Human Pancreatic Islet Proteome by Two-Dimensional LC/MS/MS

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Thomas O.; Jacobs, Jon M.; Gritsenko, Marina A.; Fontes, Ghislaine; Qian, Weijun; Camp, David G.; Poitout, Vincent J.; Smith, Richard D.

    2006-12-01

    Research to elucidate the pathogenesis of type 1 diabetes mellitus has traditionally focused on the genetic and immunological factors associated with the disease, and, until recently, has not considered the target cell. While there have been reports detailing proteomic analyses of established islet cell lines or isolated rodent islets, the information gained is not always easily extrapolated to humans. Therefore, extensive characterization of the human islet proteome could result in better understanding of islet biology and lead to more effective treatment strategies. We have applied a two-dimensional LC-MS/MS-based analysis to the characterization of the human islet proteome, resulting in the detection of 29,021 unique peptides corresponding to 4,925 proteins. As expected, major islet hormones (insulin, glucagon, somatostatin), beta-cell enriched secretory products (IAPP), ion channels (K-ATP channel), and transcription factors (PDX-1, Nkx 6.1, HNF-1 beta) were detected. In addition, significant proteome coverage of metabolic enzymes and cellular pathways was obtained, including the insulin signaling cascade and the MAP kinase, NF-κβ, and JAK/STAT pathways. This work represents the most extensive characterization of the human islet proteome to date and provides a peptide reference library that may be utilized in future studies of islet biology and type 1 diabetes.

  19. Supravital dithizone staining in the isolation of human and rat pancreatic islets

    DEFF Research Database (Denmark)

    Hansen, W A; Christie, M R; Kahn, R;

    1989-01-01

    stain red on incubation with dithizone solution. Tissue selected on the basis of dithizone staining was shown to contain insulin-positive cells and to accumulate insulin in the medium during a subsequent period in tissue culture. Experiments with rat islets indicated that the dithizone treatment had no...... effect on insulin release in tissue culture, on acute responses to stimulatory glucose concentrations or on the insulin content of cells. These results suggest that dithizone staining can assist in the identification of islets from the human pancreas and may prove to be a useful tool in developing......Dithizone, a zinc chelating agent, is known to selectively stain the islets of Langerhans in the pancreas. In the present study, we have used this stain to aid the identification of islets in material obtained by collagenase digestion of human pancreas. Islets were shown to rapidly and reversibly...

  20. Nonenzymatic cryogenic isolation of therapeutic cells: novel approach for enzyme-free isolation of pancreatic islets using in situ cryopreservation of islets and concurrent selective freeze destruction of acinar tissue.

    Science.gov (United States)

    Taylor, Michael J; Baicu, Simona C

    2014-01-01

    Cell-based therapies, which all involve processes for procurement and reimplantation of living cells, currently rely upon expensive, inconsistent, and even toxic enzyme digestion processes. A prime example is the preparation of isolated pancreatic islets for the treatment of type 1 diabetes by transplantation. To avoid the inherent pitfalls of these enzymatic methods, we have conceptualized an alternative approach based on the hypothesis that cryobiological techniques can be used for differential freeze destruction of the pancreas (Px) to release islets that are selectively cryopreserved in situ. Pancreata were procured from juvenile pigs using approved procedures. The concept of cryoisolation is based on differential processing of the pancreas in five stages: 1) infiltrating islets in situ preferentially with a cryoprotectant (CPA) cocktail via antegrade perfusion of the major arteries; 2) retrograde ductal infusion of water to distend the acinar; 3) freezing the entire Px solid to dithizone for identification of intact islets and with Syto 13/PI for fluorescence viability testing and glucose-stimulated insulin release assessment. As predicted, the cryoisolate contained small fragments of residual tissue comprising an amorphous mass of acinar tissue with largely intact and viable (>90%) embedded islets. Islets were typically larger (range 50-500 µm diameter) than their counterparts isolated from juvenile pigs using conventional enzyme digestion techniques. Functionally, the islets from replicate cryoisolates responded to a glucose challenge with a mean stimulation index = 3.3 ± 0.7. An enzyme-free method of islet isolation relying on in situ cryopreservation of islets with simultaneous freeze destruction of acinar tissue is feasible and proposed as a new and novel method that avoids the problems associated with conventional collagenase digestion methods. PMID:23992741

  1. Inhibitory effects of aloe carboxypeptidase fraction on streptozotocin-induced enhancement of vascular permeability in the pancreatic islets.

    Science.gov (United States)

    Beppu, H; Shimpo, K; Chihara, T; Tamai, I; Nomoto-Yamaji, S; Ozaki, S; Ito, S; Kuzuya, H

    2006-01-01

    The protective actions of components isolated from Aloe arborescens Miller var. natalensis Berger (Kidachi aloe in Japanese) on streptozotocin (Sz)-induced necrosis of B cells in the pancreatic islets of the mouse were investigated to clarify its action mechanism involved in anti-diabetic effects. In this experiment, phenol low molecular weight components of aloin and aloin A that were anti-oxidants and derived from the leaf skin or pulp extract, an aloe carboxypeptidase fraction that is a inhibitor of enhanced vascular permeability and a glycoprotein component that decreases blood glucose were tested with mice precedently administered with Sz which is known as a cytotoxin specific to B cells. The results showed that the treatment group receiving Sz followed by the aloe carboxypeptidase fraction increased the inhibition of dye leakage by 75.8% (paloe carboxypeptidase fraction group also increased the inhibition effect by 68.4% (paloe-derived protease known to inhibit the acetic acid-related enhancement of intraperitoneal vascular permeability in mice. Further, the elevation of blood glucose in Sz-induced diabetic mice intraperitoneally given the aloe carboxypeptitase fraction was significantly (p<0.01-0.001) restrained at 3, 7 and 14 days after the injection as compared to the control group given solvent only. The results of this experiment suggested that the inhibitory effect on the enhancement of vascular permeability related to the vascular acute inflammatory response at Sz-induced lesions of pancreatic islets was involved in the action mechanism of this enzyme. PMID:16360933

  2. Hormone-sensitive lipase deficiency suppresses insulin secretion from pancreatic islets of Lep{sup ob/ob} mice

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, Motohiro [Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Yahagi, Naoya, E-mail: nyahagi-tky@umin.ac.jp [Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Laboratory of Molecular Physiology on Energy Metabolism, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); 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 [Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Yagyu, Hiroaki [Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498 (Japan); Gotoda, Takanari [Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Nagai, Ryozo [Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Shimano, Hitoshi; Yamada, Nobuhiro [Advanced Biomedical Applications, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaragi 305-8575 (Japan); and others

    2009-09-25

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

  3. Peroxisome proliferator-activated receptor-gamma agonist, rosiglitazone, protects against nephropathy and pancreatic islet abnormalities in Zucker fatty rats.

    Science.gov (United States)

    Buckingham, R E; Al-Barazanji, K A; Toseland, C D; Slaughter, M; Connor, S C; West, A; Bond, B; Turner, N C; Clapham, J C

    1998-08-01

    Rosiglitazone (BRL 49653), a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist and potent insulin action-enhancing agent, was given in the diet (50 micromol/kg of diet) to male Zucker rats ages 6-7 weeks for 9 months (prevention group). In this treatment mode, rosiglitazone prolonged the time to onset of proteinuria from 3 to 6 months and markedly reduced the rate of its subsequent progression. Progression was also retarded when treatment was commenced (intervention group) after proteinuria had become established (4 months; ages 24-25 weeks). In either treatment mode, rosiglitazone normalized urinary N-acetyl-beta-D-glucosaminidase activity, a marker for renal proximal tubular damage, and ameliorated the rise in systolic blood pressure that occurred coincidentally with the development of proteinuria in Zucker fatty control rats. The renal protective action of rosiglitazone was verified morphologically. Thus in the prevention group there was an absence of the various indexes of chronic nephropathy that were prominent in the Zucker fatty control group, namely, glomerulosclerosis, dilated tubules containing proteinaceous casts, a loss of functional microvilli on the tubular epithelium, and varying degrees of chronic interstitial nephritis. An intermediate pathology was observed in the intervention group. Also, pancreatic islet hyperplasia, ultrastructural evidence of beta-cell work hypertrophy, and derangement of alpha-cell distribution within the islet were prominent features of Zucker fatty control rats, but these adaptive changes were ameliorated (intervention group) or prevented (prevention group) by rosiglitazone treatment. These data demonstrate that treatment of Zucker fatty rats with rosiglitazone produced substantial protection over a prolonged period against the development and progression of renal injury and the adaptive changes to pancreatic islet morphology caused by sustained hyperinsulinemia. PMID:9703335

  4. Fibrin, a scaffold material for islet transplantation and pancreatic endocrine tissue engineering.

    Science.gov (United States)

    Riopel, Matthew; Trinder, Mark; Wang, Rennian

    2015-02-01

    Fibrin is derived from fibrinogen during injury to produce a blood clot and thus promote wound repair. Composed of different domains, including Arg-Gly-Asp amino acid motifs, fibrin is used extensively as a hydrogel and sealant in the clinic. By binding to cell surface receptors like integrins and acting as a supportive 3D scaffold, fibrin has been useful in promoting cell differentiation, proliferation, function, and survival. In particular, fibrin has been able to maintain islet cell architecture, promote beta cell insulin secretion, and islet angiogenesis, as well as inducing a protective effect against cell death. During islet transplantation, fibrin improved neovascularization and islet function. These improvements resulted in reduced number of transplanted islets necessary to reverse diabetes. Therefore, fibrin, as a biocompatible and biodegradable scaffold, should be considered during subcutaneous islet transplantation and beta cell expansion in vitro to ensure maintenance of islet cell function, proliferation, and survival to develop effective cell-based therapies for the treatment of diabetes. PMID:24947304

  5. Interaction of Glycolysis and Mitochondrial Respiration in Metabolic Oscillations of Pancreatic Islets

    DEFF Research Database (Denmark)

    Bertram, Richard; Satin, Leslie S.; Pedersen, Morten Gram;

    2007-01-01

    of membrane potential and Ca2+ concentration in islets. It also accounts for temporal data on oxygen consumption in islets. A recent challenge to the notion that glycolytic oscillations drive slow Ca2+ oscillations in islets are data showing that oscillations in Ca2+, mitochondrial oxygen consumption, and NAD...... oscillations that are superimposed are due to Ca2+ feedback onto metabolism or ion channels. We extend a previous mathematical model based on this hypothesis to include a more detailed description of mitochondrial metabolism. We demonstrate that this model can account for typical oscillatory patterns...

  6. 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...

  7. Islet Cells Serve as Cells of Origin of Pancreatic Gastrin-Positive Endocrine Tumors

    DEFF Research Database (Denmark)

    Bonnavion, Rémy; Teinturier, Romain; Jaafar, Rami;

    2015-01-01

    The cells of origin of pancreatic gastrinomas remain an enigma, since no gastrin-expressing cells are found in the normal adult pancreas. It was proposed that the cellular origin of pancreatic gastrinomas may come from either the pancreatic cells themselves or gastrin-expressing cells which have ...

  8. Inherent ER stress in pancreatic islet β cells causes self-recognition by autoreactive T cells in type 1 diabetes.

    Science.gov (United States)

    Marré, Meghan L; Profozich, Jennifer L; Coneybeer, Jorge T; Geng, Xuehui; Bertera, Suzanne; Ford, Michael J; Trucco, Massimo; Piganelli, Jon D

    2016-08-01

    Type 1 diabetes (T1D) is an autoimmune disease characterized by pancreatic β cell destruction induced by islet reactive T cells that have escaped central tolerance. Many physiological and environmental triggers associated with T1D result in β cell endoplasmic reticulum (ER) stress and dysfunction, increasing the potential for abnormal post-translational modification (PTM) of proteins. We hypothesized that β cell ER stress induced by environmental and physiological conditions generates abnormally-modified proteins for the T1D autoimmune response. To test this hypothesis we exposed the murine CD4(+) diabetogenic BDC2.5 T cell clone to murine islets in which ER stress had been induced chemically (Thapsigargin). The BDC2.5 T cell IFNγ response to these cells was significantly increased compared to non-treated islets. This β cell ER stress increased activity of the calcium (Ca(2+))-dependent PTM enzyme tissue transglutaminase 2 (Tgase2), which was necessary for full stress-dependent immunogenicity. Indeed, BDC2.5 T cells responded more strongly to their antigen after its modification by Tgase2. Finally, exposure of non-antigenic murine insulinomas to chemical ER stress in vitro or physiological ER stress in vivo caused increased ER stress and Tgase2 activity, culminating in higher BDC2.5 responses. Thus, β cell ER stress induced by chemical and physiological triggers leads to β cell immunogenicity through Ca(2+)-dependent PTM. These findings elucidate a mechanism of how β cell proteins are modified and become immunogenic, and reveal a novel opportunity for preventing β cell recognition by autoreactive T cells. PMID:27173406

  9. Regulation of leptin on insulin secretion and sulfonulurea receptor 1 transcription level in isolated rats pancreatic islets

    Institute of Scientific and Technical Information of China (English)

    袁莉; 安汉祥; 邓秀玲; 李卓娅

    2003-01-01

    Objective To investigate the regulation of leptin on insulin secretion and expression of ATP-sensitive potassium channel subunit sulfonulurea receptor 1 (SUR1) mRNA, and to determine whether the effects of leptin are mediated through known intracellular signaling transduction. Methods Pancreatic islets were isolated by the collagenase method from male SD rats. The purified islets were incubated with different concentrations of leptin for 2 h in the presence of different concentrations of glucose. Insulin release was measured using radioimmunoassay. Expression of SUR1 mRNA was detected by RT-PCR. Results In the presence of leptin 2 nmol/L, insulin release was significantly inhibited at either 11.1 or 16.7 mmol/L glucose concentration (bothP<0.05), but insulin release was not altered at glucose of 5.6 mmol/L physiological concentration. The dose-response experiment showed that the maximal effect of leptin on insulin secretion achieved at 2 nmol/L. Exposure of islets to 2 nmol/L leptin induced a significant increase of SUR1 transcription evels by 71% (P<0.01) at 11.1 mmol/L glucose and by 56% (P<0.05) at 16.7 mmol/L glucose concentration. Selective phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor wortmannin significantly prevented the leptin effect on insulin secretion and SUR1 mRNA expression. Conclusions Regulatory effects of leptin on insulin secretion could be biphasic at different concentrations of glucose and leptin. The stimulatory regulation of SUR1 transcription levels may be mediated through activation of PI 3-kinase pathway, which may be a possible mechanism of leptin in regulating insulin secretion.

  10. Selective deletion of Pten in pancreatic beta cells leads to increased islet mass and resistance to STZ-induced diabetes.

    Science.gov (United States)

    Stiles, Bangyan L; Kuralwalla-Martinez, Christine; Guo, Wei; Gregorian, Caroline; Wang, Ying; Tian, Jide; Magnuson, Mark A; Wu, Hong

    2006-04-01

    Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a lipid phosphatase. PTEN inhibits the action of phosphatidylinositol-3-kinase and reduces the levels of phosphatidylinositol triphosphate, a crucial second messenger for cell proliferation and survival, as well as insulin signaling. In this study, we deleted Pten specifically in the insulin producing beta cells during murine pancreatic development. Pten deletion leads to increased cell proliferation and decreased cell death, without significant alteration of beta-cell differentiation. Consequently, the mutant pancreas generates more and larger islets, with a significant increase in total beta-cell mass. PTEN loss also protects animals from developing streptozotocin-induced diabetes. Our data demonstrate that PTEN loss in beta cells is not tumorigenic but beneficial. This suggests that modulating the PTEN-controlled signaling pathway is a potential approach for beta-cell protection and regeneration therapies. PMID:16537919

  11. Evaluation of Porcine Pancreatic Islets Transplanted in the Kidney Capsules of Diabetic Mice Using a Clinically Approved Superparamagnetic Iron Oxide (SPIO) and a 1.5T MR Scanner

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoe Suk; Kim, Hyoung Su; Park, Kyong Soo; Moon, Woo Kyung [Seoul National University Hospital, Seoul (Korea, Republic of)

    2010-12-15

    To evaluate transplanted porcine pancreatic islets in the kidney capsules of diabetic mice using a clinically approved superparamagnetic iron oxide (SPIO) and a 1.5T MR scanner. Various numbers of porcine pancreatic islets labeled with Resovist, a carboxydextran-coated SPIO, were transplanted into the kidney capsules of normal mice and imaged with a 3D FIESTA sequence using a 1.5T clinical MR scanner. Labeled (n = 3) and unlabeled (n = 2) islets were transplanted into the kidney capsules of streptozotocin-induced diabetic mice. Blood glucose levels and MR signal intensities were monitored for 30 days post-transplantation. There were no significant differences in viability or insulin secretion between labeled and unlabeled islets. A strong correlation ({gamma} {sup 2} > 0.94) was evident between the number of transplanted islets and T{sub 2} relaxation times quantified by MRI. Transplantation with labeled or unlabeled islets helped restore normal sustained glucose levels in diabetic mice, and nephrectomies induced the recurrence of diabetes. The MR signal intensity of labeled pancreatic islets decreased by 80% over 30 days. The transplantation of SPIO-labeled porcine islets into the kidney capsule of diabetic mice allows to restore normal glucose levels, and these islets can be visualized and quantified using a 1.5T clinical MR scanner

  12. Swim training of monosodium L-glutamate-obese mice improves the impaired insulin receptor tyrosine phosphorylation in pancreatic islets.

    Science.gov (United States)

    Miranda, Rosiane Aparecida; Branco, Renato Chaves Souto; Gravena, Clarice; Barella, Luiz Felipe; da Silva Franco, Claudinéia Conationi; Andreazzi, Ana Eliza; de Oliveira, Júlio Cezar; Picinato, Maria Cecília; de Freitas Mathias, Paulo Cezar

    2013-06-01

    The goal of the present study was to investigate changes on glucose homoeostasis and of the insulin receptor (IR) and insulin receptor substrate-1 (IRS-1) signalling in pancreatic islets from MSG-obese mice submitted to or not submitted to swim training. Swim training of 90-day-old MSG mice was used to evaluate whether signalling pathways of the IR and IRS-1 in islets are involved with the insulin resistance and glucose intolerance observed in this obese animal model. The results showed that IR tyrosine phosphorylation (pIR) was reduced by 42 % in MSG-obese mice (MSG, 6.7 ± 0.2 arbitrary units (a.u.); control, 11.5 ± 0.4 a.u.); on the other hand, exercise training increased pIR by 76 % in MSG mice without affecting control mice (MSG, 11.8 ± 0.3; control, 12.8 ± 0.2 a.u.). Although the treatment with MSG increased IRS-1 tyrosine phosphorylation (pIRS-1) by 96 % (MSG, 17.02 ± 0.6; control, 8.7 ± 0.2 a.u.), exercise training also increased it in both groups (control, 13.6 ± 0.1; MSG, 22.2 ± 1.1 a.u.). Current research shows that the practice of swim training increases the tyrosine phosphorylation of IRS-1 which can modulate the effect caused by obesity in insulin receptors. PMID:22983867

  13. Apolipoprotein CIII Reduces Proinflammatory Cytokine-Induced Apoptosis in Rat Pancreatic Islets via the Akt Prosurvival Pathway

    DEFF Research Database (Denmark)

    Størling, Joachim; Juntti-Berggren, Lisa; Olivecrona, Gunilla;

    2011-01-01

    Apolipoprotein CIII (ApoCIII) is mainly synthesized in the liver and is important for triglyceride metabolism. The plasma concentration of ApoCIII is elevated in patients with type 1 diabetes (T1D), and in vitro ApoCIII causes apoptosis in pancreatic ß-cells in the absence of inflammatory stress...... µg/ml) did not cause apoptosis. In the presence of the islet-cytotoxic cytokines IL-1ß + interferon-¿, ApoCIII reduced cytokine-mediated islet cell death and impairment of ß-cell function. ApoCIII had no effects on mitogen-activated protein kinases (c-Jun N-terminal kinase, p38, and ERK) and had...... of the survival serine-threonine kinase Akt. Inhibition of the Akt signaling pathway by the phosphatidylinositol 3 kinase inhibitor LY294002 counteracted the antiapoptotic effect of ApoCIII on cytokine-induced apoptosis. We conclude that ApoCIII in the presence of T1D-relevant proinflammatory cytokines reduces...

  14. Results of open and robot-assisted pancreatectomies with autologous islet transplantations: treating chronic pancreatitis and preventing surgically induced diabetes.

    Science.gov (United States)

    Gruessner, R W G; Cercone, R; Galvani, C; Rana, A; Porubsky, M; Gruessner, A C; Rilo, H

    2014-01-01

    For patients with chronic pancreatitis (CP), standard surgical procedures (eg, partial or total resections, drainage procedures) are inadequate treatment options, because they do not confer pain relief and they leave patients prone to brittle diabetes and hypoglycemia. The combination of total pancreatectomy and islet autotransplantation (TP-IAT), however, can create insulin-independent and pain-free states. At our center, from August 2009 through August 2013, 61 patients with CP underwent either open or robot-assisted TP-IAT. The 30-day mortality rate was 0%. The transplanted islet equivalents per body weight ranged from 10,000 to 17,770. In all, 19% of the patients became insulin independent (after a range of 1-24 months); 27% of patients required <10 units of insulin. Moreover, at 12 months after surgery, 71% of the patients were pain free and no longer required analgesics. Our metabolic outcomes could have been even better if most patients had been referred at an earlier disease stage; instead, ∼80% had already undergone surgical procedures, and 91% had abnormal results on preoperative continuous glucose monitoring tests. Only if patients with CP are referred early for a TP-IAT-rather than being subjected to additional inadequate endoscopic and surgical procedures-can insulin-independent and pain-free states be accomplished in most. PMID:25131087

  15. Abnormal anxiety- and depression-like behaviors in mice lacking both central serotonergic neurons and pancreatic islet cells.

    Science.gov (United States)

    Jia, Yun-Fang; Song, Ning-Ning; Mao, Rong-Rong; Li, Jin-Nan; Zhang, Qiong; Huang, Ying; Zhang, Lei; Han, Hui-Li; Ding, Yu-Qiang; Xu, Lin

    2014-01-01

    Dysfunction of central serotonin (5-HT) system has been proposed to be one of the underlying mechanisms for anxiety and depression, and the association of diabetes mellitus and psychiatric disorders has been noticed by the high prevalence of anxiety/depression in patients with diabetes mellitus. This promoted us to examine these behaviors in central 5-HT-deficient mice and those also suffering with diabetes mellitus. Mice lacking either 5-HT or central serotonergic neurons were generated by conditional deletion of Tph2 or Lmx1b respectively. Simultaneous depletion of both central serotonergic neurons and pancreatic islet cells was achieved by administration of diphtheria toxin (DT) in Pet1-Cre;Rosa26-DT receptor (DTR) mice. The central 5-HT-deficient mice showed reduced anxiety-like behaviors as they spent more time in and entered more often into the light box in the light/dark box test compared with controls; similar results were observed in the elevated plus maze test. However, they displayed no differences in the immobility time of the forced swimming and tail suspension tests suggesting normal depression-like behaviors in central 5-HT-deficient mice. As expected, DT-treated Pet1-Cre;Rosa26-DTR mice lacking both central serotonergic neurons and pancreatic islet endocrine cells exhibited several classic diabetic symptoms. Interestingly, they displayed increased anxiety-like behaviors but reduced immobility time in the forced swimming and tail suspension tests. Furthermore, the hippocampal neurogenesis was dramatically enhanced in these mice. These results suggest that the deficiency of central 5-HT may not be sufficient to induce anxiety/depression-like behaviors in mice, and the enhanced hippocampal neurogenesis may contribute to the altered depression-like behaviors in the 5-HT-deficient mice with diabetes. Our current investigation provides understanding the relationship between diabetes mellitus and psychiatric disorders.

  16. Abnormal anxiety- and depression-like behaviors in mice lacking both central serotonergic neurons and pancreatic islet cells

    Directory of Open Access Journals (Sweden)

    Yun-Fang eJia

    2014-09-01

    Full Text Available Dysfunction of central serotonin (5-HT system has been proposed to be one of the underlying mechanisms for anxiety and depression, and the association of diabetes mellitus and psychiatric disorders has been noticed by the high prevalence of anxiety/depression in patients with diabetes mellitus. This promoted us to examine these behaviors in central 5-HT-deficient mice and those also suffering with diabetes mellitus. Mice lacking either 5-HT or central serotonergic neurons were generated by conditional deletion of Tph2 or Lmx1b respectively. Simultaneous depletion of both central serotonergic neurons and pancreatic islet cells was achieved by administration of diphtheria toxin (DT in Pet1-Cre;Rosa26-DT receptor (DTR mice. The central 5-HT-deficient mice showed reduced anxiety-like behaviors as they spent more time in and entered more often into the light box in the light/dark box test compared with controls; similar results were observed in the elevated plus maze test. However, they displayed no differences in the immobility time of the forced swimming and tail suspension tests suggesting normal depression-like behaviors in central 5-HT-deficient mice. As expected, DT-treated Pet1-Cre;Rosa26-DTR mice lacking both central serotonergic neurons and pancreatic islet endocrine cells exhibited several classic diabetic symptoms. Interestingly, they displayed increased anxiety-like behaviors but reduced immobility time in the forced swimming and tail suspension tests. Furthermore, the hippocampal neurogenesis was dramatically enhanced in these mice. These results suggest that the deficiency of central 5-HT may not be sufficient to induce anxiety/depression-like behaviors in mice, and the enhanced hippocampal neurogenesis may contribute to the altered depression-like behaviors in the 5-HT-deficient mice with diabetes. Our current investigation provides a novel insight into understanding the relationship between diabetes mellitus and psychiatric disorders.

  17. JANEX-1, a JAK3 inhibitor, protects pancreatic islets from cytokine toxicity through downregulation of NF-κB activation and the JAK/STAT pathway

    International Nuclear Information System (INIS)

    JANEX-1/WHI-P131, a selective Janus kinase 3 (JAK3) inhibitor, has been shown to delay the onset of diabetes in the NOD mouse model. However, the molecular mechanism by which JANEX-1 protects pancreatic β-cells is unknown. In the current study, we investigated the role of JANEX-1 on interleukin (IL)-1β and interferon (IFN)-γ-induced β-cell damage using isolated islets. JANEX-1-pretreated islets showed resistance to cytokine toxicity, namely suppressed nitric oxide (NO) production, reduced inducible form of NO synthase (iNOS) expression, and decreased islet destruction. The molecular mechanism by which JANEX-1 inhibits iNOS expression was mediated through suppression of the nuclear factor κB (NF-κB) and JAK/signal transducer and activator of transcription (STAT) pathways. Islets treated with the cytokines downregulated the protein levels of suppressor of cytokine signaling (SOCS)-1 and SOCS-3, but pretreatment with JANEX-1 attenuated these decreases. Additionally, islets from JAK3-/- mice were more resistant to cytokine toxicity than islets from control mice. These results demonstrate that JANEX-1 protects β-cells from cytokine toxicity through suppression of the NF-κB and JAK/STAT pathways and upregulation of SOCS proteins, suggesting that JANEX-1 may be used to preserve functional β-cell mass.

  18. Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin

    DEFF Research Database (Denmark)

    Dolva, L O; Welinder, B S; Hanssen, K F;

    1983-01-01

    Thyrotropin-releasing hormone immunoreactivity (TRH-IR) was measured in isolated islets and in medium from rat pancreatic islets maintained in organ culture. TRH-IR in methanol extracts of both islets and culture medium was eluted in the same position as synthetic TRH by ion-exchange and gel...... chromatography and exhibited dilution curves parallel with synthetic TRH in radioimmunoassay. [3H]Histidine was incorporated into a component that reacted with TRH antiserum and had the same retention time as synthetic TRH on reversed-phase high-performance liquid chromatography. A continuous release of TRH......-IR into the culture medium was observed from islets of both 5-d-old (newborn) and 30-d-old (adult) rats with a maximum on the second day of culture (28.7 +/- 7.0 and 13.3 +/- 3.6 fmol/islet per d, respectively). The content of TRH-IR was higher in freshly isolated islets from newborn rats (22.4 +/- 2.3 fmol...

  19. JANEX-1, a JAK3 inhibitor, protects pancreatic islets from cytokine toxicity through downregulation of NF-{kappa}B activation and the JAK/STAT pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Na; Kim, Eun-Kyung; Song, Mi-Young [Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Choi, Ha-Na; Moon, Woo Sung [Department of Pathology, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Park, Sung-Joo [Department of Herbology, School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Park, Jin-Woo [Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kwon, Kang-Beom, E-mail: desson@wonkwang.ac.kr [Department of Physiology, School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Park, Byung-Hyun, E-mail: bhpark@chonbuk.ac.kr [Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2009-07-15

    JANEX-1/WHI-P131, a selective Janus kinase 3 (JAK3) inhibitor, has been shown to delay the onset of diabetes in the NOD mouse model. However, the molecular mechanism by which JANEX-1 protects pancreatic {beta}-cells is unknown. In the current study, we investigated the role of JANEX-1 on interleukin (IL)-1{beta} and interferon (IFN)-{gamma}-induced {beta}-cell damage using isolated islets. JANEX-1-pretreated islets showed resistance to cytokine toxicity, namely suppressed nitric oxide (NO) production, reduced inducible form of NO synthase (iNOS) expression, and decreased islet destruction. The molecular mechanism by which JANEX-1 inhibits iNOS expression was mediated through suppression of the nuclear factor {kappa}B (NF-{kappa}B) and JAK/signal transducer and activator of transcription (STAT) pathways. Islets treated with the cytokines downregulated the protein levels of suppressor of cytokine signaling (SOCS)-1 and SOCS-3, but pretreatment with JANEX-1 attenuated these decreases. Additionally, islets from JAK3{sup -/-} mice were more resistant to cytokine toxicity than islets from control mice. These results demonstrate that JANEX-1 protects {beta}-cells from cytokine toxicity through suppression of the NF-{kappa}B and JAK/STAT pathways and upregulation of SOCS proteins, suggesting that JANEX-1 may be used to preserve functional {beta}-cell mass.

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

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    1985-01-01

    Glucose has been suggested to be the most important stimulus for beta cell replication in vivo and in vitro. In order to study the relationship between insulin secretion and DNA synthesis, newborn rat islets were cultured in the presence of different concentrations of glucose, theophylline and 3-...

  1. 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 iso...

  2. 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...

  3. Homogenization of heterogeneously coupled bistable ODE's - applied to excitation waves in pancreatic islets of Langerhans

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram

    2004-01-01

    We consider a lattice of coupled identical differential equations. The coupling is between nearest neighbors and of resistance type, but the strength of coupling varies from site to site. Such a lattice can, for example, model an islet of Langerhans, where the sites in the lattice model individua...

  4. Proteins differentially expressed in human beta-cells-enriched pancreatic islet cultures and human insulinomas

    DEFF Research Database (Denmark)

    Terra, Letícia F; Teixeira, Priscila C; Wailemann, Rosangela A M;

    2013-01-01

    In view of the great demand for human beta-cells for physiological and medical studies, we generated cell lines derived from human insulinomas which secrete insulin, C-peptide and express neuroendocrine and islet markers. In this study, we set out to characterize their proteomes, comparing them t...

  5. PANCREATIC BETA-CELL FUNCTION AND ISLET-CELL PROLIFERATION - EFFECT OF HYPERINSULINEMIA

    NARCIS (Netherlands)

    KOITER, TR; WIJKSTRA, S; VANDERSCHAAFVERDONK, GCJ; MOES, H; SCHUILING, GA

    1995-01-01

    Pancreatic beta-cell function was studied in adult female rats, in which endogenous insulin demand was fully met by SC infusion of human insulin (4.8 IU/24 h) for 6 days, resulting in hyperinsulinaemia and severe hypoglycaemia. The amount of pancreatic endocrine tissue declined by 40%, (pro)insulin

  6. Differentiation of rat marrow mesenchymal stem cells into pancreatic islet beta-cells

    Institute of Scientific and Technical Information of China (English)

    Li-Bo Chen; Xiao-Bing Jiang; Lian Yang

    2004-01-01

    AIM: To explore the possibility of marrow mesenchymal stem cells (MSC)in vitro differentiating into functional isletlike cells and to test the diabetes therapeutic potency of Islet-like cells.METHODS: Rat MSCs were isolated from Wistar rats and cultured. Passaged MSCs were induced to differentiate into islet-like cells under following conditions: pre-induction with L-DMEM including 10 mmol/L nicotinamide+1 mmol/L β-mercaptoethanol+200 mL/L fetal calf serum (FSC) for 24 h,followed by induction with serum free H-DMEM solution including 10 mmol/L nicotinamide+ 1 mmol/L,β-mercaptoethanol for 10 h. Differentiated cells were observed under inverse microscopy, insulin and nestin expressed in differentiated cells were detected with immunocytochemistry. Insulin excreted from differentiated cells was tested with radioimmunoassay. Rat diabetic models were made to test in vivo function of differentiated MSCs.RESULTS: Typical islet -like clustered cells were observed.Insulin mRNA and protein expressions were positive in differentiated cells, and nestin could be detected in predifferentiated cells. Insulin excreted from differentiated MSCs (446.93±102.28 IU/L) was much higher than that from pre-differentiated MSCs (2.45±0.81 IU/L (P<0.01).Injected differentiated MSCs cells could down-regulate glucose level in diabetic rats.CONCLUSION: Islet-like functional cells can be differentiated from marrow mesenchymal stem cells, which may be a new procedure for clinical diabetes stem -cell therapy, these cells can control blood glucose level in diabetic rats. MSCs may play an important role in diabetes therapy by islet differentiation and transplantation.

  7. Acute Exposure to a Precursor of Advanced Glycation End Products Induces a Dual Effect on the Rat Pancreatic Islet Function

    Directory of Open Access Journals (Sweden)

    Ghada Elmhiri

    2014-01-01

    Full Text Available Aim. Chronic diseases are the leading cause of death worldwide. Advanced glycation end products, known as AGEs, are a major risk factor for diabetes onset and maintenance. Methylglyoxal (MG, a highly reactive metabolite of glucose, is a precursor for the generation of endogenous AGEs. Methods. In this current study we incubated in vitro pancreatic islets from adult rats in absence or presence of MG (10 μmol/l with different concentrations of glucose and different metabolic components (acetylcholine, epinephrine, potassium, forskolin, and leucine. Results. Different effects of MG on insulin secretion were evidenced. In basal glucose stimulation (5.6 mM, MG induced a significant (P<0.05 increase of insulin secretion. By contrast, in higher glucose concentrations (8.3 mM and 16.7 mM, MG significantly inhibited insulin secretion (P<0.05. In the presence of potassium, forskolin, and epinephrine, MG enhanced insulin secretion (P<0.05, while when it was incubated with acetylcholine and leucine, MG resulted in a decrease of insulin secretion (P<0.05. Conclusion. We suggest that MG modulates the secretion activity of beta-cell depending on its level of stimulation by other metabolic factors. These results provide insights on a dual acute effect of MG on the pancreatic cells.

  8. Adult Human Biliary Tree Stem Cells Differentiate to β-Pancreatic Islet Cells by Treatment with a Recombinant Human Pdx1 Peptide.

    Science.gov (United States)

    Cardinale, Vincenzo; Puca, Rosa; Carpino, Guido; Scafetta, Gaia; Renzi, Anastasia; De Canio, Michele; Sicilia, Francesca; Nevi, Lorenzo; Casa, Domenico; Panetta, Rocco; Berloco, Pasquale Bartolomeo; Reid, Lola M; Federici, Giorgio; Gaudio, Eugenio; Maroder, Marella; Alvaro, Domenico

    2015-01-01

    Generation of β-pancreatic cells represents a major goal in research. The aim of this study was to explore a protein-based strategy to induce differentiation of human biliary tree stem cells (hBTSCs) towards β-pancreatic cells. A plasmid containing the sequence of the human pancreatic and duodenal homeobox 1 (PDX1) has been expressed in E. coli. Epithelial-Cell-Adhesion-Molecule positive hBTSCs or mature human hepatocyte cell line, HepG2, were grown in medium to which Pdx1 peptide was added. Differentiation toward pancreatic islet cells were evaluated by the expression of the β-cell transcription factors, Pdx1 and musculoapo-neurotic fibrosarcoma oncogene homolog A, and of the pancreatic hormones, insulin, glucagon, and somatostatin, investigated by real time polymerase chain reaction, western blot, light microscopy and immunofluorescence. C-peptide secretion in response to high glucose was also measured. Results indicated how purified Pdx1 protein corresponding to the primary structure of the human Pdx1 by mass spectroscopy was efficiently produced in bacteria, and transduced into hBTSCs. Pdx1 exposure triggered the expression of both intermediate and mature stage β-cell differentiation markers only in hBTSCs but not in HepG2 cell line. Furthermore, hBTSCs exposed to Pdx1 showed up-regulation of insulin, glucagon and somatostatin genes and formation of 3-dimensional islet-like structures intensely positive for insulin and glucagon. Finally, Pdx1-induced islet-like structures exhibited glucose-regulated C-peptide secretion. In conclusion, the human Pdx1 is highly effective in triggering hBTSC differentiation toward functional β-pancreatic cells. PMID:26252949

  9. Adult Human Biliary Tree Stem Cells Differentiate to β-Pancreatic Islet Cells by Treatment with a Recombinant Human Pdx1 Peptide.

    Directory of Open Access Journals (Sweden)

    Vincenzo Cardinale

    Full Text Available Generation of β-pancreatic cells represents a major goal in research. The aim of this study was to explore a protein-based strategy to induce differentiation of human biliary tree stem cells (hBTSCs towards β-pancreatic cells. A plasmid containing the sequence of the human pancreatic and duodenal homeobox 1 (PDX1 has been expressed in E. coli. Epithelial-Cell-Adhesion-Molecule positive hBTSCs or mature human hepatocyte cell line, HepG2, were grown in medium to which Pdx1 peptide was added. Differentiation toward pancreatic islet cells were evaluated by the expression of the β-cell transcription factors, Pdx1 and musculoapo-neurotic fibrosarcoma oncogene homolog A, and of the pancreatic hormones, insulin, glucagon, and somatostatin, investigated by real time polymerase chain reaction, western blot, light microscopy and immunofluorescence. C-peptide secretion in response to high glucose was also measured. Results indicated how purified Pdx1 protein corresponding to the primary structure of the human Pdx1 by mass spectroscopy was efficiently produced in bacteria, and transduced into hBTSCs. Pdx1 exposure triggered the expression of both intermediate and mature stage β-cell differentiation markers only in hBTSCs but not in HepG2 cell line. Furthermore, hBTSCs exposed to Pdx1 showed up-regulation of insulin, glucagon and somatostatin genes and formation of 3-dimensional islet-like structures intensely positive for insulin and glucagon. Finally, Pdx1-induced islet-like structures exhibited glucose-regulated C-peptide secretion. In conclusion, the human Pdx1 is highly effective in triggering hBTSC differentiation toward functional β-pancreatic cells.

  10. Distinct differences in the responses of the human pancreatic β-cell line EndoC-βH1 and human islets to proinflammatory cytokines.

    Science.gov (United States)

    Oleson, Bryndon J; McGraw, Jennifer A; Broniowska, Katarzyna A; Annamalai, Mani; Chen, Jing; Bushkofsky, Justin R; Davis, Dawn B; Corbett, John A; Mathews, Clayton E

    2015-09-01

    While insulinoma cells have been developed and proven to be extremely useful in studies focused on mechanisms controlling β-cell function and viability, translating findings to human β-cells has proven difficult because of the limited access to human islets and the absence of suitable insulinoma cell lines of human origin. Recently, a human β-cell line, EndoC-βH1, has been derived from human fetal pancreatic buds. The purpose of this study was to determine whether human EndoC-βH1 cells respond to cytokines in a fashion comparable to human islets. Unlike most rodent-derived insulinoma cell lines that respond to cytokines in a manner consistent with rodent islets, EndoC-βH1 cells fail to respond to a combination of cytokines (IL-1, IFN-γ, and TNF) in a manner consistent with human islets. Nitric oxide, produced following inducible nitric oxide synthase (iNOS) expression, is a major mediator of cytokine-induced human islet cell damage. We show that EndoC-βH1 cells fail to express iNOS or produce nitric oxide in response to this combination of cytokines. Inhibitors of iNOS prevent cytokine-induced loss of human islet cell viability; however, they do not prevent cytokine-induced EndoC-βH1 cell death. Stressed human islets or human islets expressing heat shock protein 70 (HSP70) are resistant to cytokines, and, much like stressed human islets, EndoC-βH1 cells express HSP70 under basal conditions. Elevated basal expression of HSP70 in EndoC-βH1 cells is consistent with the lack of iNOS expression in response to cytokine treatment. While expressing HSP70, EndoC-βH1 cells fail to respond to endoplasmic reticulum stress activators, such as thapsigargin. These findings indicate that EndoC-βH1 cells do not faithfully recapitulate the response of human islets to cytokines. Therefore, caution should be exercised when making conclusions regarding the actions of cytokines on human islets when using this human-derived insulinoma cell line. PMID:26084699

  11. Hemoglobin A1C Percentage in Nonhuman Primates: A Useful Tool to Monitor Diabetes before and after Porcine Pancreatic Islet Xenotransplantation

    Directory of Open Access Journals (Sweden)

    Marco Marigliano

    2011-01-01

    Full Text Available Non-human primates (NHPs are a very valuable experimental model for diabetes research studies including experimental pancreatic islet transplantation. In particular NHPs are the recipients of choice to validate pigs as possible source of pancreatic islets. The aim of this study was to quantify glycated hemoglobin percentage in NHPs and to assess whether changes in values reflect the metabolic trends after diabetes induction and islet transplantation. Sera from 15 NHPs were analyzed. 9 NHPs were rendered diabetic with streptozotocin (STZ, and 3 of them received porcine islet transplants. Hemoglobin A1c (HbA1c percentage was measured with an assay based on a latex immunoagglutination inhibition methodology. Whereas diabetes and its duration were associated with increasing HbA1c levels, postislet transplantation blood glucose normalization was paralleled by a decrease in the HbA1c percentage. Our data provide evidence that HbA1c is a useful tool to monitor glucose metabolism in NHPs.

  12. Economic Burden of Chronic Pancreatitis and Implications of Total Pancreatectomy and Autologous Islet Cell Transplantation

    Directory of Open Access Journals (Sweden)

    Ashley R Dennison

    2008-09-01

    Full Text Available Context Heterotopic pancreas is usually an incidental finding during pathologic evaluation of gastrointestinal polyps or lesions encoun-tered during endoscopy for nonspecific symptoms or unrelated conditions. However, the same neoplastic processes that occur in normal pancreas also can occur in pancreatic heterotopias. Case report We report two cases of intraductal papillary mucinous neoplasms arising in pancreatic heterotopia within the duodenum of two patients. These cases are among the first reports of neoplasia occurring in pancre-atic heterotopia of the duodenum. Both patients are being managed expectantly, as there is currently no consensus regarding the proper follow up in these cases, particularly those that have been incompletely excised. Conclusion These cases highlight the potential for neo-plasia in pancreatic heterotopia and emphasize the importance of careful evaluation of these lesions. Close clinical follow up and possible excision may be warranted in patients with concerning pathologic or clinical findings.

  13. Transplantation of allogeneic pancreatic islets and pancreatic stem cells-derived islet-like structures to treat diabetes%同种异体胰岛及胰腺干细胞来源的胰岛样结构序贯移植治疗糖尿病

    Institute of Scientific and Technical Information of China (English)

    郑伟; 范志勇; 黄盛; 高琪; 张福琴; 宋振顺

    2008-01-01

    目的 观察同种异体大鼠胰岛及胰腺干细胞来源的胰岛样结构序贯移植在糖尿病治疗中的作用.方法 分离胰腺组织获得胰岛及胰腺导管上皮细胞,将具有干细胞潜能的胰腺导管上皮细胞在体外培养27d.将新鲜分离的胰岛(200±50)个及诱导分化2周的胰腺干细胞来源的胰岛样结构(2×106)个序贯移植到糖尿病大鼠的肾被膜下观察大鼠的血糖及生存情况.结果 将胰岛及胰腺干细胞来源的胰岛样结构序贯移植到同一糖尿病大鼠3周后血糖仍在5 mmol/L水平,对照组血糖无明显下降.结论 胰腺干细胞可诱导分化为分泌胰岛素的胰岛样结构,胰岛及胰腺干细胞来源的胰岛样结构序贯移植对大鼠糖尿病有治疗作用.%Objective To observe the transplantation of allogeneie pancreatic islets and pancreatic stem cells-derived islet-like structures in the treatment of diabetes.Methods The pancreatic tissue was isolated to obtain the islets and pancreatic duet epithelial cells.Pancreatic duct epithelial cells which have the potential of stem cells were cultivated in vitro for up to 27 days.The freshly isolated panereatiC islets (200±50)and pancreatic stem cells-denved islet-like structures(2×106)collected 2 weeks after differentiation in vitro were transplanted under the kidney capsule of the same rats.Blood glucose level and the subsistence state were observed.Results Blood gheese level was 5 mmol/L in diabefic rats 3 weeks after the transplantation of freshly isolated allogeneie pancreatic islzts and pancreatic stem cell-derived islet-like structures.In control group.the blood slucese level had significant decrease.Condusion PancreatiC stem cells can differentiate into islet-like structures in vitro.Pancreatic islets and pancreatic stem cells-derived islet-like structures have a potential apphcation to cure diabetes.

  14. Pancreatic hormones are expressed on the surfaces of human and rat islet cells through exocytotic sites

    DEFF Research Database (Denmark)

    Larsson, L I; Hutton, J C; Madsen, O D;

    1989-01-01

    . Electron microscopy reveals the labeling to occur at sites of exocytotic granule release, involving the surfaces of extruded granule cores. The surfaces of islet cells were labeled both by polyclonal and monoclonal antibodies, excluding that receptor-interacting, anti-idiotypic hormone antibodies were...... for these results. It is concluded that the staining reflects interactions between the appropriate antibodies and exocytotic sites of hormone release....

  15. Automated assessment of β-cell area and density per islet and patient using TMEM27 and BACE2 immunofluorescence staining in human pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Markus P Rechsteiner

    Full Text Available In this study we aimed to establish an unbiased automatic quantification pipeline to assess islet specific features such as β-cell area and density per islet based on immunofluorescence stainings. To determine these parameters, the in vivo protein expression levels of TMEM27 and BACE2 in pancreatic islets of 32 patients with type 2 diabetes (T2D and in 28 non-diabetic individuals (ND were used as input for the automated pipeline. The output of the automated pipeline was first compared to a previously developed manual area scoring system which takes into account the intensity of the staining as well as the percentage of cells which are stained within an islet. The median TMEM27 and BACE2 area scores of all islets investigated per patient correlated significantly with the manual scoring and with the median area score of insulin. Furthermore, the median area scores of TMEM27, BACE2 and insulin calculated from all T2D were significantly lower compared to the one of all ND. TMEM27, BACE2, and insulin area scores correlated as well in each individual tissue specimen. Moreover, islet size determined by costaining of glucagon and either TMEM27 or BACE2 and β-cell density based either on TMEM27 or BACE2 positive cells correlated significantly. Finally, the TMEM27 area score showed a positive correlation with BMI in ND and an inverse pattern in T2D. In summary, automated quantification outperforms manual scoring by reducing time and individual bias. The simultaneous changes of TMEM27, BACE2, and insulin in the majority of the β-cells suggest that these proteins reflect the total number of functional insulin producing β-cells. Additionally, β-cell subpopulations may be identified which are positive for TMEM27, BACE2 or insulin only. Thus, the cumulative assessment of all three markers may provide further information about the real β-cell number per islet.

  16. 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.

  17. Discovery of novel glucose-regulated proteins in isolated human pancreatic islets using LC-MS/MS-based proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Rutledge, Alexandra C.; Fontes, Ghislaine; Gritsenko, Marina A.; Norbeck, Angela D.; Anderson, David J.; Waters, Katrina M.; Adkins, Joshua N.; Smith, Richard D.; Poitout, Vincent; Metz, Thomas O.

    2012-07-06

    The prevalence of diabetes mellitus is increasing dramatically throughout the world, and the disease has become a major public health issue. The most common form of the disease, type 2 diabetes, is due in part to insufficient insulin production from the pancreatic beta-cell. Since glucose is the most potent and physiologically important regulators of beta-cell function under physiological conditions, understanding the insulin secretory defect underlying type 2 diabetes requires a better understanding of glucose regulation of beta-cell function. To this aim, a bottom-up LC-MS/MS-based proteomics approach was used to profile pooled islets from multiple donors under basal (5 mM) or high (15 mM) glucose conditions. Our analysis discovered 256 differentially abundant proteins ({approx}p < 0.05) after 24 h of high glucose exposure from more than 4500 identified in total. Several novel glucose-regulated proteins were elevated under high glucose conditions, including regulators of mRNA splicing (Pleiotropic regulator 1), processing (Retinoblastoma binding protein 6), and function (Nuclear RNA export factor 1), in addition to Neuron navigator 1 and Plasminogen activator inhibitor 1. Proteins whose abundances markedly decreased during incubation at 15 mM glucose included Bax inhibitor 1 and Synaptotagmin-17. Many proteins found to be differentially abundant after high glucose stimulation were uncharacterized or hypothetical. These findings expand our knowledge of glucose regulation of the human islet proteome and suggest many hitherto unknown responses to glucose that require additional studies to explore novel functional roles.

  18. Dynamics of glucose-induced membrane recruitment of protein kinase C beta II in living pancreatic islet beta-cells.

    Science.gov (United States)

    Pinton, Paolo; Tsuboi, Takashi; Ainscow, Edward K; Pozzan, Tullio; Rizzuto, Rosario; Rutter, Guy A

    2002-10-01

    The mechanisms by which glucose may affect protein kinase C (PKC) activity in the pancreatic islet beta-cell are presently unclear. By developing adenovirally expressed chimeras encoding fusion proteins between green fluorescent protein and conventional (betaII), novel (delta), or atypical (zeta) PKCs, we show that glucose selectively alters the subcellular localization of these enzymes dynamically in primary islet and MIN6 beta-cells. Examined by laser scanning confocal or total internal reflection fluorescence microscopy, elevated glucose concentrations induced oscillatory translocations of PKCbetaII to spatially confined regions of the plasma membrane. Suggesting that increases in free cytosolic Ca(2+) concentrations ([Ca(2+)](c)) were primarily responsible, prevention of [Ca(2+)](c) increases with EGTA or diazoxide completely eliminated membrane recruitment, whereas elevation of cytosolic [Ca(2+)](c) with KCl or tolbutamide was highly effective in redistributing PKCbetaII both to the plasma membrane and to the surface of dense core secretory vesicles. By contrast, the distribution of PKCdelta.EGFP, which binds diacylglycerol but not Ca(2+), was unaffected by glucose. Measurement of [Ca(2+)](c) immediately beneath the plasma membrane with a ratiometric "pericam," fused to synaptic vesicle-associated protein-25, revealed that depolarization induced significantly larger increases in [Ca(2+)](c) in this domain. These data demonstrate that nutrient stimulation of beta-cells causes spatially and temporally complex changes in the subcellular localization of PKCbetaII, possibly resulting from the generation of Ca(2+) microdomains. Localized changes in PKCbetaII activity may thus have a role in the spatial control of insulin exocytosis.

  19. Control of Insulin Secretion by Production of Reactive Oxygen Species: Study Performed in Pancreatic Islets from Fed and 48-Hour Fasted Wistar Rats

    Science.gov (United States)

    Riva, Patrícia; Simões, Daniel; Curi, Rui; Carpinelli, Angelo Rafael

    2016-01-01

    Mitochondria and NADPH oxidase are important sources of reactive oxygen species in particular the superoxide radical (ROS) in pancreatic islets. These molecules derived from molecular oxygen are involved in pancreatic β-cells signaling and control of insulin secretion. We examined the involvement of ROS produced through NADPH oxidase in the leucine- and/or glucose-induced insulin secretion by pancreatic islets from fed or 48-hour fasted rats. Glucose-stimulated insulin secretion (GSIS) in isolated islets was evaluated at low (2.8 mM) or high (16.7 mM) glucose concentrations in the presence or absence of leucine (20 mM) and/or NADPH oxidase inhibitors (VAS2870–20 μM or diphenylene iodonium—DPI—5 μM). ROS production was determined in islets treated with dihydroethidium (DHE) or MitoSOX Red reagent for 20 min and dispersed for fluorescence measurement by flow cytometry. NADPH content variation was examined in INS-1E cells (an insulin secreting cell line) after incubation in the presence of glucose (2.8 or 16.7 mM) and leucine (20 mM). At 2.8 mM glucose, VAS2870 and DPI reduced net ROS production (by 30%) and increased GSIS (by 70%) in a negative correlation manner (r = -0.93). At 16.7 mM glucose or 20 mM leucine, both NADPH oxidase inhibitors did not alter insulin secretion neither net ROS production. Pentose phosphate pathway inhibition by treatment with DHEA (75 μM) at low glucose led to an increase in net ROS production in pancreatic islets from fed rats (by 40%) and induced a marked increase (by 144%) in islets from 48-hour fasted rats. The NADPH/NADP+ ratio was increased when INS-1E cells were exposed to high glucose (by 4.3-fold) or leucine (by 3-fold). In conclusion, increased ROS production through NADPH oxidase prevents the occurrence of hypoglycemia in fasting conditions, however, in the presence of high glucose or high leucine levels, the increased production of NADPH and the consequent enhancement of the activity of the antioxidant defenses

  20. Clock-controlled output gene Dbp is a regulator of Arnt/Hif-1β gene expression in pancreatic islet β-cells

    Energy Technology Data Exchange (ETDEWEB)

    Nakabayashi, Hiroko; Ohta, Yasuharu, E-mail: yohta@yamaguchi-u.ac.jp; Yamamoto, Masayoshi; Susuki, Yosuke; Taguchi, Akihiko; Tanabe, Katsuya; Kondo, Manabu; Hatanaka, Masayuki; Nagao, Yuko; Tanizawa, Yukio, E-mail: tanizawa@yamaguchi-u.ac.jp

    2013-05-03

    Highlights: •Arnt mRNA expressed in a circadian manner in mouse pancreatic islets. •Expressions of Dbp and Arnt damped in the islets of a diabetic model mouse. •DBP and E4BP4 regulate Arnt promoter activity by direct binding. •Arnt may have a role in connecting circadian rhythm and metabolism. -- Abstract: Aryl hydrocarbon receptor nuclear translocator (ARNT)/hypoxia inducible factor-1β (HIF-1β) has emerged as a potential determinant of pancreatic β-cell dysfunction and type 2 diabetes in humans. An 82% reduction in Arnt expression was observed in islets from type 2 diabetic donors as compared to non-diabetic donors. However, few regulators of Arnt expression have been identified. Meanwhile, disruption of the clock components CLOCK and BMAL1 is known to result in hypoinsulinemia and diabetes, but the molecular details remain unclear. In this study, we identified a novel molecular connection between Arnt and two clock-controlled output genes, albumin D-element binding protein (Dbp) and E4 binding protein 4 (E4bp4). By conducting gene expression studies using the islets of Wfs1{sup −/−} A{sup y}/a mice that develop severe diabetes due to β-cell apoptosis, we demonstrated clock-related gene expressions to be altered in the diabetic mice. Dbp mRNA decreased by 50%, E4bp4 mRNA increased by 50%, and Arnt mRNA decreased by 30% at Zeitgever Time (ZT) 12. Mouse pancreatic islets exhibited oscillations of clock gene expressions. E4BP4, a D-box negative regulator, oscillated anti-phase to DBP, a D-box positive regulator. We also found low-amplitude circadian expression of Arnt mRNA, which peaked at ZT4. Over-expression of DBP raised both mRNA and protein levels of ARNT in HEK293 and MIN6 cell lines. Arnt promoter-driven luciferase reporter assay in MIN6 cells revealed that DBP increased Arnt promoter activity by 2.5-fold and that E4BP4 competitively inhibited its activation. In addition, on ChIP assay, DBP and E4BP4 directly bound to D-box elements within the

  1. Advanced glycation end-products induce apoptosis in pancreatic islet endothelial cells via NF-κB-activated cyclooxygenase-2/prostaglandin E2 up-regulation.

    Directory of Open Access Journals (Sweden)

    Kuo-Cheng Lan

    Full Text Available Microvascular complications eventually affect nearly all patients with diabetes. Advanced glycation end-products (AGEs resulting from hyperglycemia are a complex and heterogeneous group of compounds that accumulate in the plasma and tissues in diabetic patients. They are responsible for both endothelial dysfunction and diabetic vasculopathy. The aim of this study was to investigate the cytotoxicity of AGEs on pancreatic islet microvascular endothelial cells. The mechanism underlying the apoptotic effect of AGEs in pancreatic islet endothelial cell line MS1 was explored. The results showed that AGEs significantly decreased MS1 cell viability and induced MS1 cell apoptosis in a dose-dependent manner. AGEs dose-dependently increased the expressions of cleaved caspase-3, and cleaved poly (ADP-ribose polymerase in MS1 cells. Treatment of MS1 cells with AGEs also resulted in increased nuclear factor (NF-κB-p65 phosphorylation and cyclooxygenase (COX-2 expression. However, AGEs did not affect the expressions of endoplasmic reticulum (ER stress-related molecules in MS1 cells. Pretreatment with NS398 (a COX-2 inhibitor to inhibit prostaglandin E2 (PGE2 production reversed the induction of cleaved caspase-3, cleaved PARP, and MS1 cell viability. Moreover, AGEs significantly increased the receptor for AGEs (RAGE protein expression in MS1 cells, which could be reversed by RAGE neutralizing antibody. RAGE Neutralizing antibody could also reverse the induction of cleaved caspase-3 and cleaved PARP and decreased cell viability induced by AGEs. These results implicate the involvement of NF-κB-activated COX-2/PGE2 up-regulation in AGEs/RAGE-induced islet endothelial cell apoptosis and cytotoxicity. These findings may provide insight into the pathological processes within the pancreatic islet microvasculature induced by AGEs accumulation.

  2. Expression and function of Set7/9 in pancreatic islets.

    Science.gov (United States)

    Ogihara, Takeshi; Vanderford, Nathan L; Maier, Bernhard; Stein, Roland W; Mirmira, Raghavendra G

    2009-01-01

    Histone tail acetylation and methylation are known to enhance accessibility of islet genes to transcription factors and the basal transcriptional machinery.  In this brief report, we follow up on a recent study in which we identified the islet enriched factor Set7/9 as a potentially important histone methyltransferase in β-cells (Deering, et al. Diabetes 2009; 58:185-93).  We had suggested that the methylation of H3-Lys4 by Set7/9 enhances accessibility of the insulin gene to the basal transcriptional machinery.  Consistent with this hypothesis, we show here that RNA polymerase II occupancy at the insulin and IAPP genes is considerably enhanced in β-cells compared to α cells (or NIH3T3 cells), and that the converse is true for RNA polymerase II occupancy at the glucagon gene. The enrichment of Set7/9 in β-cells appears to be dependent upon Pdx1, as knockdown of Pdx1 in INS-1 β-cells using small hairpin RNAs almost completely abolishes Set7/9 expression.  A LacZ expression vector driven by the -6.5 kilobase pair Set7/9 promoter that contains putative Pdx1 binding sites shows β-cell-line-specific expression.  Taken together, our data support further the hypothesis that Pdx1-dependent Set7/9 expression may be crucial to enhancing chromatin accessibility and transcription of β-cell genes. PMID:21099283

  3. 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 and PRL have been shown to stimulate proliferation and insulin production in islets of Langerhans. To identify genes regulated by GH/PRL in islets, we performed differential screening of a complementary DNA library from neonatal rat islets cultured for 24 h with human GH (hGH). One hGH-induced...

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Effects of Glucagon-Like Peptide 1 on PDX-1, PAX-6 and NKx2.2 Gene Expressions in Isolated Pancreatic Islets

    Institute of Scientific and Technical Information of China (English)

    Dai Cui; Wei Tang; Cuiping Liu; Kuanfeng Xu; Chao Liu

    2006-01-01

    Objective: To observe the effect of glucagon-like peptide 1 (GLP-1) on the gene expressions of transcription factors (PDX-1, PAX-6 and NKx2.2) in freshly isolated rat pancreatic islets and investigate the associated physiological and therapeutic implication of GLP-1. Methods: The isolated rat islets were incubated with 10 nmol/L GLP-1 for 1, 3 and 5 days, respectively. Total cellular RNA was extracted and the expressions of PDX-1, PAX-6 and NKx2.2 gene were detected by semiquantity RT-PCR. Results: Compared with the control group, the PDX-1, PAX-6 and NKx2.2 gene expressions were significantly increased after co-cultured with GLP-1 for 1 day (P < 0.05). The effect was shown in a time-dependent manner. All three gene expressions reached the peak on the 5th day. Conclusion: GLP-1 can improve the function of pancreatic islet by regulating the gene expressions of transcription factors in β cells.

  6. Unique splicing pattern of the TCF7L2 gene in human pancreatic islets

    DEFF Research Database (Denmark)

    Osmark, P; Hansson, O; Jonsson, Anna Elisabet;

    2009-01-01

    Intronic variation in the TCF7L2 gene exhibits the strongest association to type 2 diabetes observed to date, but the mechanism whereby this genetic variation translates into altered biological function is largely unknown. A possible explanation is a genotype-dependent difference in the complex...... splicing pattern; however, this has not previously been characterised in pancreatic or insulin target tissues. Here, the detailed TCF7L2 splicing pattern in five human tissues is described and dependence on risk genotype explored....

  7. Palmitic acid increase levels of pancreatic duodenal homeobox-1 and p38/stress-activated protein kinase in islets from rats maintained on a low protein diet.

    Science.gov (United States)

    Arantes, Vanessa C; Reis, Marise A B; Latorraca, Márcia Q; Ferreira, Fabiano; Stoppiglia, Luiz Fabrízio; Carneiro, Everardo M; Boschero, Antonio C

    2006-12-01

    A severe reduction in insulin release in response to glucose is consistently noticed in protein-deprived rats and is attributed partly to the chronic exposure to elevated levels of NEFA. Since the pancreatic and duodenal transcription factor homeobox 1 (PDX-1) is important for the maintenance of beta-cell physiology, and since PDX-1 expression is altered in the islets of rats fed a low protein (LP) diet and that rats show high NEFA levels, we assessed PDX-1 and insulin mRNA expression, as well as PDX-1 and p38/stress activated protein kinase 2 (SAPK2) protein expression, in islets from young rats fed low (6%) or normal (17%; control) protein diets and maintained for 48 h in culture medium containing 5.6 mmol/l glucose, with or without 0.6 mmol/l palmitic acid. We also measured glucose-induced insulin secretion and glucose metabolism. Insulin secretion by isolated islets in response to 16.7 mmol/l glucose was reduced in LP compared with control rats. In the presence of NEFA, there was an increase in insulin secretion in both groups. At 2.8 mmol/l glucose, the metabolism of this sugar was reduced in LP islets, regardless of the presence of this fatty acid. However, when challenged with 16.7 mmol/l glucose, LP and control islets showed a severe reduction in glucose oxidation in the presence of NEFA. The PDX-1 and insulin mRNA were significantly higher when NEFA was added to the culture medium in both groups of islets. The effect of palmitic acid on PDX-1 and p38/SAPK2 protein levels was similar in LP and control islets, but the increase was much more evident in LP islets. These results demonstrate the complex interrelationship between nutrients in the control of insulin release and support the view that fatty acids play an important role in glucose homeostasis by affecting molecular mechanisms and stimulus/secretion coupling pathways. PMID:17181874

  8. Multiple Sites of Purinergic Control of Insulin Secretion in Mouse Pancreatic β-Cells

    DEFF Research Database (Denmark)

    Poulsen, Claus R.; Bokvist, Krister; Olsen, Hervør L.;

    1999-01-01

    Insulin secretion, pancreatic islets, purinoceptors, calcium currents, potassium conductance, cell mebrane capacitance......Insulin secretion, pancreatic islets, purinoceptors, calcium currents, potassium conductance, cell mebrane capacitance...

  9. Ca2+ signals induced from calcium stores in pancreatic islet β cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In single rat pancreatic β cells,using fura-2 microfluorometry to measure [Ca2+]i response upon different stimuli,the ways of calcium regulation have been studied.When the extracellular calcium concentration was 2.5 mmol/L,either 60 mmol/L KCl,20 mmol/L D-glucose or 0.1 mmol/L tolbutamide induced increase in [Ca2+]i.Such increase in [Ca2+]i was absent when the same stimuli were applied under zero extracellular calcium.These results indicate that the increase of [Ca2+]i is induced by the activation of voltage-dependent calcium channels in β cells.The manifold forms of [Ca2+]i change induced by glucose imply that the effects of glucose are complex.5 mmol/L caffeine or 5 mmol/L MCh increase the [Ca2+]i ,which is independent of the external calcium,suggesting that [Ca2+]i can be regulated by Ca2+ release from not only the IP3-sensitive but also the ryanodine sensitive calcium stores in β cells.The latency of Ca responses for IP3 pathway (5 s) is faster than that for ryanodine pathway (30 s).It is concluded that there are multiple calcium stores in rat pancreatic β cells.

  10. Chronic exercise increases plasma brain-derived neurotrophic factor levels, pancreatic islet size, and insulin tolerance in a TrkB-dependent manner.

    Directory of Open Access Journals (Sweden)

    Alberto Jiménez-Maldonado

    Full Text Available BACKGROUND: Physical exercise improves glucose metabolism and insulin sensitivity. Brain-derived neurotrophic factor (BDNF enhances insulin activity in diabetic rodents. Because physical exercise modifies BDNF production, this study aimed to investigate the effects of chronic exercise on plasma BDNF levels and the possible effects on insulin tolerance modification in healthy rats. METHODS: Wistar rats were divided into five groups: control (sedentary, C; moderate- intensity training (MIT; MIT plus K252A TrkB blocker (MITK; high-intensity training (HIT; and HIT plus K252a (HITK. Training comprised 8 weeks of treadmill running. Plasma BDNF levels (ELISA assay, glucose tolerance, insulin tolerance, and immunohistochemistry for insulin and the pancreatic islet area were evaluated in all groups. In addition, Bdnf mRNA expression in the skeletal muscle was measured. PRINCIPAL FINDINGS: Chronic treadmill exercise significantly increased plasma BDNF levels and insulin tolerance, and both effects were attenuated by TrkB blocking. In the MIT and HIT groups, a significant TrkB-dependent pancreatic islet enlargement was observed. MIT rats exhibited increased liver glycogen levels following insulin administration in a TrkB-independent manner. CONCLUSIONS/SIGNIFICANCE: Chronic physical exercise exerted remarkable effects on insulin regulation by inducing significant increases in the pancreatic islet size and insulin sensitivity in a TrkB-dependent manner. A threshold for the induction of BNDF in response to physical exercise exists in certain muscle groups. To the best of our knowledge, these are the first results to reveal a role for TrkB in the chronic exercise-mediated insulin regulation in healthy rats.

  11. 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

    Proghrelin, the precursor of the orexigenic and adipogenic peptide hormone ghrelin, is synthetized in endocrine (A-like) cells in the gastric mucosa. During its cellular processing, proghrelin gives rise to the 28-amino acid peptide desacyl ghrelin, which after octanoylation becomes active acyl...... 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...

  12. Insulin-dependent diabetes mellitus secondary to chronic pancreatitis is not associated with HLA or the occurrence of islet-cell antibodies

    DEFF Research Database (Denmark)

    Larsen, S; Hilsted, J; Jakobsen, B K;

    1990-01-01

    We assessed HLA-DR types and investigated serum samples for islet-cell cytoplasmic antibodies (ICA) in 31 Danish patients with chronic pancreatitis. The antigen frequencies were compared with those in 1177 unrelated healthy Danish controls. Twenty patients had insulin-dependent diabetes and 11 had...... normal intravenous glucose tolerance. No significant differences in the frequencies of DR3, DR4, or DR2 were found between patients with insulin-dependent diabetes and patients with normal glucose tolerance or between any of these groups and controls. ICA were negative in all patients with chronic...

  13. Apoptosis in pancreatic β-islet cells in Type 2 diabetes.

    Science.gov (United States)

    Tomita, Tatsuo

    2016-08-01

    Apoptosis plays important roles in the pathophysiology of Type 2 diabetes mellitus (T2DM). The etiology of T2DM is multifactorial, including obesity-associated insulin resistance, defective insulin secretion, and loss of β-cell mass through β-cell apoptosis. β-cell apoptosis is mediated through a milliard of caspase family cascade machinery in T2DM. The glucose-induced insulin secretion is the principle pathophysiology of diabetes and insufficient insulin secretion results in chronic hyperglycemia, diabetes. Recently, hyperglycemia-induced β-cell apoptosis has been extensively studied on the balance of pro-apoptotic Bcl-2 proteins (Bad, Bid, Bik, and Bax) and anti-apoptotic Bcl family (Bcl-2 and Bcl-xL) toward apoptosis in vitro isolated islets and insulinoma cell culture. Apoptosis can only occur when the concentration of pro-apoptotic Bcl-2 exceeds that of anti-apoptotic proteins at the mitochondrial membrane of the intrinsic pathway. A bulk of recent research on hyperglycemia-induced apoptosis on β-cells unveiled complex details on glucose toxicity on β-cells in molecular levels coupled with cell membrane potential by adenosine triphosphate generation through K+ channel closure, opening Ca2+ channel and plasma membrane depolarization. Furthermore, animal models using knockout mice will shed light on the basic understanding of the pathophysiology of diabetes as a glucose metabolic disease complex, on the balance of anti-apoptotic Bcl family and pro-apoptotic genes. The cumulative knowledge will provide a better understanding of glucose metabolism at a molecular level and will lead to eventual prevention and therapeutic application for T2DM with improving medications. PMID:27483174

  14. Transcriptional profiling of type 1 diabetes genes on chromosome 21 in a rat beta-cell line and human pancreatic islets

    DEFF Research Database (Denmark)

    Bergholdt, R.; Karlsen, A.E.; Hagedorn, Peter;

    2007-01-01

    likely candidate genes influencing beta-cell function in this region. Two array-based approaches were used, a rat insulinoma cell line (INS-1alphabeta) overexpressing pancreatic duodenum homeobox 1 (pdx-1) and treated with interleukin 1beta (IL-1beta) as well as human pancreatic islets stimulated...... with a mixture of cytokines. Several candidate genes with likely functional significance in T1D were identified. Genes showing differential expression in the two approaches were highly similar, supporting the role of these specific gene products in cytokine-induced beta-cell damage. These were genes involved...... in cytokine signaling, oxidative phosphorylation, defense responses and apoptosis. The analyses, furthermore, revealed several transcription factor binding sites shared by the differentially expressed genes and by genes demonstrating highly similar expression profiles with these genes. Comparable findings...

  15. Sodium levels of human pancreatic donors are a critical factor for determination of islet efficacy and survival.

    Science.gov (United States)

    Qi, Meirigeng; Luis, Valiente; Bilbao, Shiela; Omori, Keiko; Rawson, Jeffrey; McFadden, Brian; Juan, Jemily; Nair, Indu; Mullen, Yoko; El-Shahawy, Mohamed; Dafoe, Donald; Kandeel, Fouad; Al-Abdullah, Ismail H

    2015-03-01

    Organs from hypernatremia (elevated Na+) donors when used for transplantation have had dismal outcomes. However, islet isolation from hypernatremic donors for both transplantation and research applications has not yet been investigated. A retrospective analysis of in vivo and in vitro islet function studies was performed on islets isolated from hypernatremic (serum sodium levels≥160 meq/l) and normal control (serum sodium levels≤155 meq/l) donors. Twelve isolations from 32 hypernatremic and 53 isolations from 222 normal donors were randomly transplanted into diabetic NOD Scid mice. Sodium levels upon pancreas procurement were significantly elevated in the hypernatremia group (163.5±0.6 meq/l) compared with the normal control group (145.9±0.4 meq/l) (Preduced islet recovery postculture. The efficacy of islets from hypernatremia donors diminished when transplanted into diabetic recipients. PMID:25537495

  16. Pancreatic islet regeneration and some liver biochemical parameters of leaf extracts of Vitex doniana in normal and streptozotocin-induced diabetic albino rats

    Institute of Scientific and Technical Information of China (English)

    Okpe Oche; Ibrahim Sani; Njoku Godwin Chilaka; Ndidi Uche Samuel; Atabo Samuel

    2014-01-01

    Objective: To test two water soluble extracts (aqueous and ethanolic) obtained from the leaves ofVitex doniana in normal and streptozotocin-induced diabetic rats for their effects on pancreatic endocrine tissues and serum marker enzymes for a period of 21 d. Methods: A total of 55 rats divided into 11 groups of 5 rats each were assigned into diabetic and non-diabetic groups and followed by a daily administration of ethanolic and aqueous extracts for 21 d. Group 1 was the normal control while group 7 was treated with standard drug.Results:The histopathological studies of the diabetic rats indicated increase in the volume density of islets, percent of β-cells and size of islet in the groups that received the plant extracts, which suggested regeneration of β-cells along with β-cells repairs, as compared with the non-treated diabetic control which showed complete degeneration of the islet cells. There was significant reduction (P0.01) in the serum activities of marker enzymes was observed for non-diabetic treated rats. Results of total bilirubin, direct bilirubin and unconjugated bilirubin showed that diabetic control group was significantly higher (P0.01) in total bilirubin and direct bilirubin compared with the normal control.Conclusion:This herbal therapy appears to bring about repair/regeneration of the endocrine pancreas and hepatic cells protection in the diabetic rat.

  17. All-trans retinoic acid ameliorates glycemic control in diabetic mice via modulating pancreatic islet production of vascular endothelial growth factor-A.

    Science.gov (United States)

    Chien, Chiao-Yun; Yuan, Tze-An; Cho, Candy Hsin-Hua; Chang, Fang-Pei; Mao, Wan-Yu; Wu, Ruei-Ren; Lee, Hsuan-Shu; Shen, Chia-Ning

    2016-09-01

    Patients with type 1 diabetes mellitus are associated with impairment in vitamin A metabolism. This study evaluated whether treatment with retinoic acid, the biologically active metabolite of vitamin A, can ameliorate diabetes. All-trans retinoic acid (atRA) was used to treat streptozotocin (STZ)-induced diabetic mice which revealed atRA administration ameliorated blood glucose levels of diabetic mice. This hyperglycemic amelioration was accompanied by an increase in the amount of β cells co-expressed Pdx1 and insulin and by restoration of the vascular laminin expression. The atRA-induced production of vascular endothelial growth factor-A from the pancreatic islets was possibly the key factor that mediated the restoration of islet vascularity and recovery of β-cell mass. Furthermore, the combination of islet transplantation and atRA administration significantly rescued hyperglycemia in diabetic mice. These findings suggest that vitamin A derivatives can potentially be used as a supplementary treatment to improve diabetes management and glycemic control. PMID:27381866

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

    Science.gov (United States)

    Roat, Regan; Rao, Vandana; Doliba, Nicolai M; Matschinsky, Franz M; Tobias, John W; Garcia, Eden; Ahima, Rexford S; Imai, Yumi

    2014-01-01

    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. PMID:24505268

  19. 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.

  20. Genome-wide associations between genetic and epigenetic variation influence mRNA expression and insulin secretion in human pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Anders H Olsson

    2014-11-01

    Full Text Available Genetic and epigenetic mechanisms may interact and together affect biological processes and disease development. However, most previous studies have investigated genetic and epigenetic mechanisms independently, and studies examining their interactions throughout the human genome are lacking. To identify genetic loci that interact with the epigenome, we performed the first genome-wide DNA methylation quantitative trait locus (mQTL analysis in human pancreatic islets. We related 574,553 single nucleotide polymorphisms (SNPs with genome-wide DNA methylation data of 468,787 CpG sites targeting 99% of RefSeq genes in islets from 89 donors. We identified 67,438 SNP-CpG pairs in cis, corresponding to 36,783 SNPs (6.4% of tested SNPs and 11,735 CpG sites (2.5% of tested CpGs, and 2,562 significant SNP-CpG pairs in trans, corresponding to 1,465 SNPs (0.3% of tested SNPs and 383 CpG sites (0.08% of tested CpGs, showing significant associations after correction for multiple testing. These include reported diabetes loci, e.g. ADCY5, KCNJ11, HLA-DQA1, INS, PDX1 and GRB10. CpGs of significant cis-mQTLs were overrepresented in the gene body and outside of CpG islands. Follow-up analyses further identified mQTLs associated with gene expression and insulin secretion in human islets. Causal inference test (CIT identified SNP-CpG pairs where DNA methylation in human islets is the potential mediator of the genetic association with gene expression or insulin secretion. Functional analyses further demonstrated that identified candidate genes (GPX7, GSTT1 and SNX19 directly affect key biological processes such as proliferation and apoptosis in pancreatic β-cells. Finally, we found direct correlations between DNA methylation of 22,773 (4.9% CpGs with mRNA expression of 4,876 genes, where 90% of the correlations were negative when CpGs were located in the region surrounding transcription start site. Our study demonstrates for the first time how genome-wide genetic and

  1. Genome-wide associations between genetic and epigenetic variation influence mRNA expression and insulin secretion in human pancreatic islets.

    Science.gov (United States)

    Olsson, Anders H; Volkov, Petr; Bacos, Karl; Dayeh, Tasnim; Hall, Elin; Nilsson, Emma A; Ladenvall, Claes; Rönn, Tina; Ling, Charlotte

    2014-11-01

    Genetic and epigenetic mechanisms may interact and together affect biological processes and disease development. However, most previous studies have investigated genetic and epigenetic mechanisms independently, and studies examining their interactions throughout the human genome are lacking. To identify genetic loci that interact with the epigenome, we performed the first genome-wide DNA methylation quantitative trait locus (mQTL) analysis in human pancreatic islets. We related 574,553 single nucleotide polymorphisms (SNPs) with genome-wide DNA methylation data of 468,787 CpG sites targeting 99% of RefSeq genes in islets from 89 donors. We identified 67,438 SNP-CpG pairs in cis, corresponding to 36,783 SNPs (6.4% of tested SNPs) and 11,735 CpG sites (2.5% of tested CpGs), and 2,562 significant SNP-CpG pairs in trans, corresponding to 1,465 SNPs (0.3% of tested SNPs) and 383 CpG sites (0.08% of tested CpGs), showing significant associations after correction for multiple testing. These include reported diabetes loci, e.g. ADCY5, KCNJ11, HLA-DQA1, INS, PDX1 and GRB10. CpGs of significant cis-mQTLs were overrepresented in the gene body and outside of CpG islands. Follow-up analyses further identified mQTLs associated with gene expression and insulin secretion in human islets. Causal inference test (CIT) identified SNP-CpG pairs where DNA methylation in human islets is the potential mediator of the genetic association with gene expression or insulin secretion. Functional analyses further demonstrated that identified candidate genes (GPX7, GSTT1 and SNX19) directly affect key biological processes such as proliferation and apoptosis in pancreatic β-cells. Finally, we found direct correlations between DNA methylation of 22,773 (4.9%) CpGs with mRNA expression of 4,876 genes, where 90% of the correlations were negative when CpGs were located in the region surrounding transcription start site. Our study demonstrates for the first time how genome-wide genetic and epigenetic

  2. 人胰岛的分离纯化和功能评价%Isolation, purification, and functional evaluation of human pancreatic islet

    Institute of Scientific and Technical Information of China (English)

    蔡寒青; 许世清; 门秀丽; 眭维国; 张文健; 李启东; 杨文英; 娄晋宁

    2009-01-01

    , then culture of pathogenic micro-organisms, endotoxin and procoagulant activity were detected so as to evaluate the security of the islet products. Results The mean number of the isolated islets was (229 000 ± 31 000) islet equivalents (IEQs)/pancreas or (4970 ± 1620) IEQs/g pancreatic tissue, the mean purity was (59. 0 ± 8.9) %, and the mean vitality was (89 ± 3)% for the purified islets. Immunofluorescence staining showed that there were 4 types of endocrine cells normally distributed in the islets. The mean insulin stimulation index was 8. 1 ±4. 0(3. 8 - 10. 2). The glycemia found in the diabetic nude mice decreased to normal levels from the third day after islet transplantation and maintained normal for over 30 days. The parameters of security in these islet products were under the standard scope. Conclusion Human islets obtained according to Ricordi's method reach the standard for clinical islet transplantation in number, purity, vitality, function, and security.

  3. Isolation and purification of pancreatic islets in adult donors%成人胰岛细胞的分离与纯化

    Institute of Scientific and Technical Information of China (English)

    江建新; 孙诚谊

    2011-01-01

    目的 探讨体外分离与纯化成人胰岛细胞的方法与可行性,为胰岛细胞移植治疗1型糖尿病提供大量高质量的胰岛细胞.方法 获取的成人胰腺组织称重后,采用Ⅴ型胶原酶消化法分离;再用Ficoll间断密度梯度离心纯化法纯化;在DTZ染色显微镜下,评价胰岛细胞的数量、纯度;并用体外培养、放射免疫测定胰岛素法鉴定胰岛细胞活性.结果 成人胰腺经胶原酶消化分离后,胰岛平均收获量(3 600 ±447)个/g胰腺;Ficoll间断密度梯度离心纯化后,胰岛平均收获量(2 140±207)个/g胰腺,纯度>70%;成人胰岛细胞培养2、4、6d后,测定其培养液中基础胰岛素浓度(mIU·L-1·100-1)分别为(3.302±1.63)、(3.504±1.10)、(2.921±1.13).结论 胶原酶消化法、Ficoll间断密度梯度离心纯化法分离纯化成人胰岛是有效的方法.%Objective To investigate the methods and feasibility of islets isolation and purification,and to get more islets with high purity and good function for clinical transplantation.Methods After being weighted,human pancreatic islets were isolated with type Ⅴ collagenase,and purified by Ficoll's discontinuous density gradient centrifugation.The yield and purity of islets were evaluated by dithizone(DTZ) staining under microscope,and the viability was assessed by insulin release assay in vitro.Results The average number of islets was about 3 600 ± 447 per gram pancreas after isolation and it was about 2140 ±207 after purification with more than 70% purity.2,4,6 days after islet cell culture,the basal insulin concentration of the culture medium was measured,and it was 3.302 ± 1.63,3.504 ±1.10,and 2.921 ±1.13 (mIU/L/100 islets) respectively.Conclusion Collagenase digest and Ficoll's discontinuous density gradient centrifugation are effective methods for isolation and purification of human pancreatic islets.

  4. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

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    Perl, S; Kushner, J A; Buchholz, B A; Meeker, A K; Stein, G M; Hsieh, M; Kirby, M; Pechhold, S; Liu, E H; Harlan, D M; Tisdale, J F

    2010-03-15

    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 ({sup 14}C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). {sup 14}C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA {sup 14}C content relative to a well-established {sup 14}C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA {sup 14}C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  5. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

    International Nuclear Information System (INIS)

    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 (14C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). 14C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA 14C content relative to a well-established 14C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA 14C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  6. Antibody Response to Serpin B13 Induces Adaptive Changes in Mouse Pancreatic Islets and Slows Down the Decline in the Residual Beta Cell Function in Children with Recent Onset of Type 1 Diabetes Mellitus.

    Science.gov (United States)

    Kryvalap, Yury; Lo, Chi-Wen; Manuylova, Ekaterina; Baldzizhar, Raman; Jospe, Nicholas; Czyzyk, Jan

    2016-01-01

    Type 1 diabetes mellitus (T1D) is characterized by a heightened antibody (Ab) response to pancreatic islet self-antigens, which is a biomarker of progressive islet pathology. We recently identified a novel antibody to clade B serpin that reduces islet-associated T cell accumulation and is linked to the delayed onset of T1D. As natural immunity to clade B arises early in life, we hypothesized that it may influence islet development during that time. To test this possibility healthy young Balb/c male mice were injected with serpin B13 mAb or IgG control and examined for the number and cellularity of pancreatic islets by immunofluorescence and FACS. Beta cell proliferation was assessed by measuring nucleotide analog 5-ethynyl-2'-deoxyuridine (5-EdU) incorporation into the DNA and islet Reg gene expression was measured by real time PCR. Human studies involved measuring anti-serpin B13 autoantibodies by Luminex. We found that injecting anti-serpin B13 monoclonal Ab enhanced beta cell proliferation and Reg gene expression, induced the generation of ∼80 pancreatic islets per animal, and ultimately led to increase in the beta cell mass. These findings are relevant to human T1D because our analysis of subjects just diagnosed with T1D revealed an association between baseline anti-serpin activity and slower residual beta cell function decline in the first year after the onset of diabetes. Our findings reveal a new role for the anti-serpin immunological response in promoting adaptive changes in the endocrine pancreas and suggests that enhancement of this response could potentially help impede the progression of T1D in humans.

  7. Low protein diet confers resistance to the inhibitory effects of interleukin 1beta on insulin secretion in pancreatic islets*

    Science.gov (United States)

    Vieira, E C.; Carneiro, E M.; Latorraca, M Q.; Delguingaro-Augusto, V; Amaral, M E.C.; Bosqueiro, J R.; Boschero, A C.

    2001-05-01

    High protein content in the diet during childhood and adolescence has been associated to the onset insulin-dependent diabetes mellitus. We investigated the effect of interleukin-1beta (IL-1beta) on insulin secretion, glucose metabolism, and nitrite formation by islets isolated from rats fed with normal protein (NP, 17%) or low protein (LP, 6%) after weaning. Pretreatment of islets with IL-1beta for 1 h or 24 h inhibited the insulin secretion induced by glucose in both groups, but it was less marked in LP than in NP group. Islets from LP rats exhibited a decreased IL-1beta-induced nitric oxide (NO) production, lower inhibition of D-[U(14)C]-glucose oxidation to (14)CO(2) and less pronounced effect of IL-1beta on alpha-ketoisocaproic acid-induced insulin secretion than NP islets. However, when the islets were stimulated by high concentrations of K(+) the inhibitory effect of IL-1beta on insulin secretion was not different between groups. In conclusion, protein restriction protects beta-cells of the deleterious effect of IL-1beta, apparently, by decreasing NO production. The lower NO generation in islets from protein deprived rats may be due to increased free fatty acids oxidation and consequent alteration in Ca(2+) homeostasis. PMID:11382546

  8. Complex Patterns of Metabolic and Ca2+ Entrainment in Pancreatic Islets by Oscillatory Glucose

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram; Mosekilde, Erik; Polonsky, Kenneth S.;

    2013-01-01

    fluorescence microscopy to demonstrate that glucose oscillations can induce distinct 1:1 and 1:2 entrainment of oscillations (one and two oscillations for each period of exogenous stimulus, respectively) in islet Ca2+ , NAD(P)H, and mitochondrial membrane potential. To our knowledge, this is the first...... experimental findings could be recapitulated by our recently developed mathematical model, and simulations suggested that interislet variability in 1:2 entrainment patterns reflects differences in their glucose sensitivity. Finally, our simulations and recordings showed that a heterogeneous group of islets...... synchronized during 1:2 entrainment, resulting in a clear oscillatory response from the collective. In summary, we demonstrate that oscillatory glucose can induce complex modes of entrainment of metabolically driven oscillations in islets, and provide additional support for the notion that entrainment promotes...

  9. 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

    and delta cells. METHODS: Sst-Cre mice crossed with fluorescent reporters were used to identify delta cells, while Glu-Venus (with Venus reported under the control of the Glu [also known as Gcg] promoter) mice were used to identify alpha and beta cells. Alpha, beta and delta cells were purified using flow...... 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...

  10. Differential interleukin-1 receptor antagonism on pancreatic beta and alpha cells. Studies in rodent and human islets and in normal rats

    DEFF Research Database (Denmark)

    Zumsteg, U; Reimers, J I; Pociot, F;

    1993-01-01

    , mouse and human islets exposed to recombinant human interleukin-1 beta, and on interleukin-1 beta induced changes in blood glucose, serum insulin and serum glucagon levels in Wistar Kyoto rats. The interleukin-1 receptor antagonist reduced the co-mitogenic effect of interleukin-1 beta on mouse and rat......The monokines interleukin-1 alpha and -beta have been implicated as effector molecules in the immune-mediated pancreatic beta-cell destruction leading to insulin-dependent diabetes mellitus. Here we investigated the effects of interleukin-1 receptor antagonism on insulin and glucagon release of rat...... thymocytes with a 50% inhibitory concentration of 10- and 100-fold molar excess, respectively. Complete inhibition was obtained with a 100-1,000-fold molar excess. However, at a 100-fold molar excess the interleukin-1 receptor antagonist did not antagonise the potentiating effect of interleukin-1 beta on rat...

  11. Isolation, characterization, and chromosomal mapping of the human Nkx6.1 gene (NKX6A), a new pancreatic islet homeobox gene

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Hiroshi; Permutt, M.A.; Veile, R. [Washington Univ. School of Medicine, St. Louis, MO (United States)] [and others

    1997-03-01

    Nkx6.1 (gene symbol NKX6A), a new member of the NK homeobox gene family, was recently identified in rodent pancreatic islet 13-cell lines. The pattern of expression suggested that this gene product might be important for control of islet development and/or regulation of insulin biosynthesis. We now report cloning of human NKX6A, characterization of its genomic structure, and its chromosomal localization. The predicted protein of human NKX6A contained 367 amino acids and had 97% identity to the hamster protein. The highly conserved NK decapeptide and homeodomain regions were identical between human and hamster, suggesting functional importance of these domains. The coding region spanned approximately 4.8 kb and was composed of three exons. The gene was localized to four CEPH {open_quotes}B{close_quotes} yeast artificial chromosome clones (914B4, 951G9, 981D6, and 847133), and a nearby polymorphic marker (D4S1538) on chromosome 4 was identified <1270 kb from the gene. Using fluorescence in situ hybridization, we also determined that NKX6A maps to 4q21.2-q22. 11 refs., 2 figs.

  12. Brief inactivation of c-Myc is not sufficient for sustained regression of c-Myc-induced tumours of pancreatic islets and skin epidermis

    Directory of Open Access Journals (Sweden)

    Zervou Sevasti

    2004-12-01

    Full Text Available Abstract Background Tumour regression observed in many conditional mouse models following oncogene inactivation provides the impetus to develop, and a platform to preclinically evaluate, novel therapeutics to inactivate specific oncogenes. Inactivating single oncogenes, such as c-Myc, can reverse even advanced tumours. Intriguingly, transient c-Myc inactivation proved sufficient for sustained osteosarcoma regression; the resulting osteocyte differentiation potentially explaining loss of c-Myc's oncogenic properties. But would this apply to other tumours? Results We show that brief inactivation of c-Myc does not sustain tumour regression in two distinct tissue types; tumour cells in pancreatic islets and skin epidermis continue to avoid apoptosis after c-Myc reactivation, by virtue of Bcl-xL over-expression or a favourable microenvironment, respectively. Moreover, tumours progress despite reacquiring a differentiated phenotype and partial loss of vasculature during c-Myc inactivation. Interestingly, reactivating c-Myc in β-cell tumours appears to result not only in further growth of the tumour, but also re-expansion of the accompanying angiogenesis and more pronounced β-cell invasion (adenocarcinoma. Conclusions Given that transient c-Myc inactivation could under some circumstances produce sustained tumour regression, the possible application of this potentially less toxic strategy in treating other tumours has been suggested. We show that brief inactivation of c-Myc fails to sustain tumour regression in two distinct models of tumourigenesis: pancreatic islets and skin epidermis. These findings challenge the potential for cancer therapies aimed at transient oncogene inactivation, at least under those circumstances where tumour cell differentiation and alteration of epigenetic context fail to reinstate apoptosis. Together, these results suggest that treatment schedules will need to be informed by knowledge of the molecular basis and

  13. Suppressor of cytokine signaling 1 protects rat pancreatic islets from cytokine-induced apoptosis through Janus kinase/signal transducers and activators of transcription pathway

    Institute of Scientific and Technical Information of China (English)

    SUN Qi; XIANG Ruo-lan; YANG Yan-li; FENG Kai; ZHANG Kui; DING Wen-yi

    2013-01-01

    Background Suppressor of cytokine signaling (SOCS) proteins are inhibitors of cytokine signaling pathway involved in negative feedback loops.Although SOCS1 is an important intracellular suppressor of apoptosis in a variety of cell types,its role in cytokine-induced pancreatic β-cell apoptosis remains unclear.The present study investigated potential effects of SOCS1 on the cytokine-induced pancreatic β-cell apoptosis.Methods After successfully transfected with SOCS1/pEGFP-C1 or pEGFP-C1 plasmids to overexpress SOCS1,RINm5F (rat insulinoma cell line) cells were exposed to cytokines,interferon (IFN)-γ alone,IFN-γ+interleukin (IL)-1β,IFN-y+IL-1β+tumor necrosis factor (TNF)-α respectively.Pancreatic β-cell apoptosis was assessed by using MTT,FACS,and caspase-3 activity assays.Protein phosphorylation of Janus kinase 2 (JAK2) and signal transducers and activators of transcription 1 (STAT1) were verified by Western blotting and mRNA expression of inducible nitric oxide synthase (iNOS),NF-κB and Fas were analyzed by RT-PCR.Results Overexpression of SOCS1 in RINm5F cells was shown to attenuate IFN-γ alone,IFN-γ+IL-1β and IFN-γ+TNF-α+IL-1β mediated apoptosis.Phosphorylation of JAK2 and STAT1 significantly decreased in RINm5F cells which overexpressed SOCS1 protein.Overexpression of SOCS1 significantly suppressed cytokine-induced iNOS mRNA levels.Conclusion Overexpression of SOCS1 protects pancreatic islets from cytokine-induced cell apoptosis via the JAK2/STAT1 pathway.

  14. Pancreatic Islet Transplantation

    Science.gov (United States)

    ... Research Training & Career Development Grant programs for students, postdocs, and faculty Research at NIDDK Labs, faculty, and ... diabetes, digestive and liver diseases, kidney diseases, weight control and nutrition, urologic diseases, endocrine and metabolic diseases, ...

  15. Increased L-CPT-1 activity and altered gene expression in pancreatic islets of malnourished adult rats: a possible relationship between elevated free fatty acid levels and impaired insulin secretion.

    Science.gov (United States)

    de Barros Reis, Marise Auxiliadora; Arantes, Vanessa Cristina; Cunha, Daniel Andrade; Latorraca, Márcia Queiroz; Toyama, Marcos Hikari; Carneiro, Everardo Magalhães; Boschero, Antonio Carlos

    2008-02-01

    Intrauterine growth restriction is associated with chronically elevated levels of serum fatty acids and reduced glucose-stimulated insulin secretion. Lipid metabolism in pancreatic beta cells is critical for the regulation of insulin secretion, and the chronic exposure to fatty acids results in higher palmitate oxidation rates and an altered insulin response to glucose. Using a rat model of isocaloric protein restriction, we examined whether pre- and postnatal protein malnutrition influences the properties of pancreatic islet carnitine palmitoyltransferase-1 (liver isoform, L-CPT-1), a rate-limiting enzyme that regulates fatty acid oxidation in mitochondria. The activity of L-CPT-1 in pancreatic islets increased in the low protein (LP), although the L-CPT-1 mRNA levels were unaffected by malnutrition. The susceptibility of enzyme to inhibition by malonyl-CoA was unaltered and the content of malonyl-CoA was reduced in LP cells. Because the mitochondrial oxidation of fatty acids is related to the altered expression of a number of genes encoding proteins involved in insulin secretion, the levels of expression of insulin and GLUT-2 mRNA were assessed. A reduced expression of both genes was observed in malnourished rats. These results provide further evidence that increased L-CPT-1 activity and changes in gene expression in pancreatic islets may be involved in the reduced insulin secretion seen in malnourished rats. PMID:17531461

  16. AMOUNT AND DISTRIBUTION OF COLLAGEN IN PANCREATIC TISSUE OF DIFFERENT SPECIES IN THE PERSPECTIVE OF ISLET ISOLATION PROCEDURES

    NARCIS (Netherlands)

    VANSUYLICHEM, PTR; VANDEIJNEN, JEHM; WOLTERS, GHJ; VANSCHILFGAARDE, R

    1995-01-01

    Because collagen is the major target in the enzymatic dissociation of the pancreas for islet isolation, we determined the amount of collagen and its distribution in a comparative study comprising normal pancreata of rat, dog, man, young pig, and adult pig. Collagen content was determined using a col

  17. Orexin-1 receptor co-localizes with pancreatic hormones in islet cells and modulates the outcome of streptozotocin-induced diabetes mellitus.

    Directory of Open Access Journals (Sweden)

    Ernest Adeghate

    Full Text Available Recent studies have shown that orexins play a critical role in the regulation of sleep/wake states, feeding behaviour, and reward processes. The exocrine and endocrine pancreas are involved in the regulation of food metabolism and energy balance. This function is deranged in diabetes mellitus. This study examined the pattern of distribution of orexin-1 receptor (OX1R in the endocrine cells of the pancreas of normal and diabetic Wistar (a model of type 1 diabetes, Goto-Kakizaki (GK, a model of type 2 diabetes rats and in orexin-deficient (OX-/- and wild type mice. Diabetes mellitus (DM was induced in Wistar rats and mice by streptozotocin (STZ. At different time points (12 h, 24 h, 4 weeks, 8 months and 15 months after the induction of DM, pancreatic fragments of normal and diabetic rats were processed for immunohistochemistry and Western blotting. OX1R-immunoreactive nerves were observed in the pancreas of normal and diabetic Wistar rats. OX1R was also discernible in the pancreatic islets of normal and diabetic Wistar and GK rats, and wild type mice. OX1R co-localized with insulin (INS and glucagon (GLU in the pancreas of Wistar and GK rats. The number of OX1R-positive cells in the islets increased markedly (p<0.0001 after the onset of DM. The increase in the number of OX1R-positive cells is associated with a high degree of co-localization with GLU. The number of GLU- positive cells expressing OX1R was significantly (p<0.0001 higher after the onset of DM. The tissue level of OX1R protein increased with the duration of DM especially in type 1 diabetes where it co-localized with cleaved caspase 3 in islet cells. In comparison to STZ-treated wild type mice, STZ-treated OX-/- animals exhibited reduced hyperglycemia and handled glucose more efficiently in glucose tolerance test. The findings suggest an important role for the OX-OX1R pathway in STZ-induced experimental diabetes.

  18. Cooperation by Fibroblasts and Bone Marrow-Mesenchymal Stem Cells to Improve Pancreatic Rat-to-Mouse Islet Xenotransplantation

    Science.gov (United States)

    Meana, Alvaro; Otero, Jesus; Esteban, Manuel M.

    2013-01-01

    Experimental and clinical experiences highlight the need to review some aspects of islet transplantation, especially with regard to site of grafting and control of the immune response. The subcutaneous space could be a good alternative to liver but its sparse vasculature is its main limitation. Induction of graft tolerance by using cells with immunoregulatory properties is a promising approach to avoid graft rejection. Both Fibroblasts and Mesenchymal Stem Cells (MSCs) have shown pro-angiogenic and immunomodulatory properties. Transplantation of islets into the subcutaneous space using plasma as scaffold and supplemented with fibroblasts and/or Bone Marrow-MSCs could be a promising strategy to achieve a functional extra-hepatic islet graft, without using immunosuppressive drugs. Xenogenic rat islets, autologous fibroblasts and/or allogenic BM-MSCs, were mixed with plasma, and coagulation was induced to constitute a Plasma-based Scaffold containing Islets (PSI), which was transplanted subcutaneously both in immunodeficient and immunocompetent diabetic mice. In immunodeficient diabetic mice, PSI itself allowed hyperglycemia reversion temporarily, but the presence of pro-angiogenic cells (fibroblasts or BM-MSCs) within PSI was necessary to improve graft re-vascularization and, thus, consistently maintain normoglycemia. In immunocompetent diabetic mice, only PSI containing BM-MSCs, but not those containing fibroblasts, normalized glycemia lasting up to one week after transplantation. Interestingly, when PSI contained both fibroblasts and BM-MSCs, the normoglycemia period showed an increase of 4-times with a physiological-like response in functional tests. Histology of immunocompetent mice showed an attenuation of the immune response in those grafts with BM-MSCs, which was improved by co-transplantation with fibroblasts, since they increased BM-MSC survival. In summary, fibroblasts and BM-MSCs showed similar pro-angiogenic properties in this model of islet

  19. Adoptive infusion of tolerogenic dendritic cells prolongs the survival of pancreatic islet allografts: a systematic review of 13 mouse and rat studies.

    Directory of Open Access Journals (Sweden)

    Guixiang Sun

    Full Text Available OBJECTIVE: The first Phase I study of autologous tolerogenic dendritic cells (Tol-DCs in Type 1 diabetes (T1D patients was recently completed. Pancreatic islet transplantation is an effective therapy for T1D, and infusion of Tol-DCs can control diabetes development while promoting graft survival. In this study, we aim to systematically review islet allograft survival following infusion of Tol-DCs induced by different methods, to better understand the mechanisms that mediate this process. METHODS: We searched PubMed and Embase (from inception to February 29(th, 2012 for relevant publications. Data were extracted and quality was assessed by two independent reviewers. We semiquantitatively analyzed the effects of Tol-DCs on islet allograft survival using mixed leukocyte reaction, Th1/Th2 differentiation, Treg induction, and cytotoxic T lymphocyte activity as mechanisms related-outcomes. We discussed the results with respect to possible mechanisms that promote survival. RESULTS: Thirteen articles were included. The effects of Tol-DCs induced by five methods on allograft survival were different. Survival by each method was prolonged as follows: allopeptide-pulsed Tol-DCs (42.14 ± 44 days, drug intervention (39 days, mesenchymal stem cell induction (23 days, genetic modification (8.99 ± 4.75 days, and other derivation (2.61 ± 6.98 days. The results indicate that Tol-DC dose and injection influenced graft survival. Single-dose injections of 10(4 Tol-DCs were the most effective for allograft survival, and multiple injections were not superior. Tol-DCs were also synergistic with immunosuppressive drugs or costimulation inhibitors. Possible mechanisms include donor specific T cell hyporesponsiveness, Th2 differentiation, Treg induction, cytotoxicity against allograft reduction, and chimerism induction. CONCLUSIONS: Tol-DCs induced by five methods prolong MHC mismatched islet allograft survival to different degrees, but allopeptide-pulsed host DCs

  20. Enzymes for Pancreatic Islet Isolation Impact Chemokine-Production and Polarization of Insulin-Producing β-Cells with Reduced Functional Survival of Immunoisolated Rat Islet-Allografts as a Consequence.

    Science.gov (United States)

    de Vos, Paul; Smink, Alexandra M; Paredes, Genaro; Lakey, Jonathan R T; Kuipers, Jeroen; Giepmans, Ben N G; de Haan, Bart J; Faas, Marijke M

    2016-01-01

    The primary aim of this study was to determine whether normal variations in enzyme-activities of collagenases applied for rat-islet isolation impact longevity of encapsulated islet grafts. Also we studied the functional and immunological properties of rat islets isolated with different enzyme preparations to determine whether this impacts these parameters. Rat-islets were isolated from the pancreas with two different collagenases with commonly accepted collagenase, neutral protease, and clostripain activities. Islets had a similar and acceptable glucose-induced insulin-release profile but a profound statistical significant difference in production of the chemokines IP-10 and Gro-α. The islets were studied with nanotomy which is an EM-based technology for unbiased study of ultrastructural features of islets such as cell-cell contacts, endocrine-cell condition, ER stress, mitochondrial conditions, and cell polarization. The islet-batch with higher chemokine-production had a lower amount of polarized insulin-producing β-cells. All islets had more intercellular spaces and less interconnected areas with tight cell-cell junctions when compared to islets in the pancreas. Islet-graft function was studied by implanting encapsulated and free islet grafts in rat recipients. Alginate-based encapsulated grafts isolated with the enzyme-lot inducing higher chemokine production and lower polarization survived for a two-fold shorter period of time. The lower survival-time of the encapsulated grafts was correlated with a higher influx of inflammatory cells at 7 days after implantation. Islets from the same two batches transplanted as free unencapsulated-graft, did not show any difference in survival or function in vivo. Lack of insight in factors contributing to the current lab-to-lab variation in longevity of encapsulated islet-grafts is considered to be a threat for clinical application. Our data suggest that seemingly minor variations in activity of enzymes applied for islet

  1. 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

  2. Stimulation by ATP of proinsulin to insulin conversion in isolated rat pancreatic islet secretory granules. Association with the ATP-dependent proton pump

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, C.J.; Lucas, C.A.; Mutkoski, R.L.; Orci, L.; Halban, P.A.

    1987-08-05

    Isolated rat pancreatic islets were pulse-labeled for 5 min with (/sup 3/H)leucine then chased for 25 min, during which time endogenously labeled (/sup 3/H)proinsulin becomes predominantly compartmented in immature secretory granules. The islets were then homogenized in isotonic sucrose (pH 7.4) and a beta-granule preparation obtained by differential centrifugation and discontinuous sucrose gradient ultracentrifugation. This preparation was enriched 8-fold in beta-granules. Aside from contamination with mitochondria and a limited number of lysosomes, the beta-granule preparation was essentially free of any other organelles involved in proinsulin synthesis and packaging (i.e. microsomal elements and, more particularly, Golgi complex). Conversion of endogenously labeled (/sup 3/H)proinsulin was followed in this beta-granule fraction for up to 2 h at 37 degrees C in a buffer (pH 7.3) that mimicked the cationic constituents of B-cell cytosol, during which time 92% of the beta-granules remained intact. Proinsulin conversion was analyzed by high performance liquid chromatography. The rate of proinsulin conversion to insulin was stimulated by 2.2 +/- 0.1-fold (n = 6) (at a 60-min incubation) in the presence of ATP (2 mM) and an ATP regenerating system compared to beta-granule preparations incubated without ATP. This ATP stimulation was abolished in the presence of beta-granule proton pump ATPase inhibitors (tributyltin, 2.5 microM, or 1,3-dicyclohexylcarbodiimide, 50 microM). Inhibitors of mitochondrial proton pump ATPases had no effect on the ATP stimulation of proinsulin conversion. When granules were incubated in a more acidic buffer, proinsulin conversion was increased relative to that at pH 7.3. At pH 5.5, ATP no longer stimulated conversion, and tributyltin and 1,3-dicyclohexylcarbodiimide had no effect.

  3. Stimulation by ATP of proinsulin to insulin conversion in isolated rat pancreatic islet secretory granules. Association with the ATP-dependent proton pump

    International Nuclear Information System (INIS)

    Isolated rat pancreatic islets were pulse-labeled for 5 min with [3H]leucine then chased for 25 min, during which time endogenously labeled [3H]proinsulin becomes predominantly compartmented in immature secretory granules. The islets were then homogenized in isotonic sucrose (pH 7.4) and a beta-granule preparation obtained by differential centrifugation and discontinuous sucrose gradient ultracentrifugation. This preparation was enriched 8-fold in beta-granules. Aside from contamination with mitochondria and a limited number of lysosomes, the beta-granule preparation was essentially free of any other organelles involved in proinsulin synthesis and packaging (i.e. microsomal elements and, more particularly, Golgi complex). Conversion of endogenously labeled [3H]proinsulin was followed in this beta-granule fraction for up to 2 h at 37 degrees C in a buffer (pH 7.3) that mimicked the cationic constituents of B-cell cytosol, during which time 92% of the beta-granules remained intact. Proinsulin conversion was analyzed by high performance liquid chromatography. The rate of proinsulin conversion to insulin was stimulated by 2.2 +/- 0.1-fold (n = 6) (at a 60-min incubation) in the presence of ATP (2 mM) and an ATP regenerating system compared to beta-granule preparations incubated without ATP. This ATP stimulation was abolished in the presence of beta-granule proton pump ATPase inhibitors (tributyltin, 2.5 microM, or 1,3-dicyclohexylcarbodiimide, 50 microM). Inhibitors of mitochondrial proton pump ATPases had no effect on the ATP stimulation of proinsulin conversion. When granules were incubated in a more acidic buffer, proinsulin conversion was increased relative to that at pH 7.3. At pH 5.5, ATP no longer stimulated conversion, and tributyltin and 1,3-dicyclohexylcarbodiimide had no effect

  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. Effects of ethanolic extract of Syzygium cumini (Linn) seed powder on pancreatic islets of alloxan diabetic rats.

    Science.gov (United States)

    Singh, N; Gupta, M

    2007-10-01

    The ethanolic extract of seeds of S. cumini increased body weight and decreased blood sugar level in alloxan diabetic albino rats. Level of significance for decrease in blood sugar after feeding alcoholic extract of S. cumini seeds in various doses was highly significant. The extract feeding showed definite improvement in the histopathology of islets. The most important finding is that the blood sugar level, which once dropped to normal levels after extract feeding was not elevated when extract feeding was discontinued for 15 days. PMID:17948734

  6. Massive parallel gene expression profiling of RINm5F pancreatic islet beta-cells stimulated with interleukin-1beta

    DEFF Research Database (Denmark)

    Rieneck, K; Bovin, L F; Josefsen, K;

    2000-01-01

    Interleukin 1 (IL-1) is a pleiotropic cytokine with the potential to kill pancreatic beta-cells, and this unique property is thought to be involved in the pathogenesis of type I diabetes mellitus. We therefore determined the quantitative expression of 24,000 mRNAs of RINm5F, an insulinoma cell line...... derived from rat pancreatic beta-cells, before and after challenge with 30 and 1,000 pg/ml of recombinant human IL-1beta. The highest concentration resulted in decreased insulin production and cell death over a period of 4 days. Using three different time points, 2, 4 and 24 hours after challenge, we...

  7. A trial for the quantitative determination of the acute radiation-induced pancreatic islet cell death irradiated with 200 KVp x-ray and 30 MeV fast neutron beams

    International Nuclear Information System (INIS)

    Quantitative counting of acute islet cell death of the golden hamster pancreas was adopted for the determination of radiation injury as one of the model in the slowly growing tissues (or slowly renewing tissues), such as liver, salivary gland, pancreas, kidney etc. First mode and dose response relationship of x-ray induced rapid cell death (interphase death) in golden hamster pancreatic islet cell death was investigated after 10-350 Gy irradiation with the dose rate of 4.5 Gy/min. With a latent period of 2-3 hours, pycnotic cells began to appear after irradiation. Then they reached maximum at 4-5 hours, and at 6 hours later on, their nuclei lysed completely. From the disappearance rate of the nuclei, the mean life span of pycnotic cells was estimated to be approximately 2 hours or less. Thereafter these remnants of dead cells were scavenged from the islets within 16 hours after irradiation. The mode of cell death was almost identical irregardless of different irradiation doses. Therefore through the counting of both pycnotic nuclei and normal looking nuclei at 4-5 hours after irradiation, it was possible to determine the radiosensitivity of the islet cells. Cell death by x-ray was dose-dependent and stochastic throughout all dose range even in a surviving fraction of 10-4 order. Thus obtained radio-sensitivity of the islet cells was 62.5 Gy of Do and 3.2 of n number. Unfortunately, however, in neutron irradiated pancreas, quantitation of cell death was not possible unlike in x-rays. This is because the maximum neutron dose rate available was 0.5-0.6 Gy. Therefore initial aim for the study on comparative biological effect of x-ray and neutron through the acute pancreatic cell death was failed by the dose rate problem. (author)

  8. Radiation-induced acute necrosis of the pancreatic islet and the diabetic syndrome in the golden hamster (Mesocricetus auratus)

    Energy Technology Data Exchange (ETDEWEB)

    Tsubouchi, S.; Suzuki, H.; Ariyoshi, H. (Aichi Cancer Center, Nagoya (Japan)); Matsuzawa, T. (Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis and Cancer)

    1981-07-01

    Exposure of golden hamsters to 35 000 rad of X-rays induced acute and specific necrosis of the cells of the islets of Langerhans of the pancreas within 4 hours, whereas no other tissue revealed any drastic changes which would lead to a critical illness until 36 hours. Animals began to show the characteristic signs of diabetes, that is, hyperglycaemia, hyperkalaemia, ketonemia, and acidosis at 12 hours and these continued until death, 56+-8 hours later. These were accompanied by the disappearance of ..beta..-cell granules and a decrease of plasma insulin. Treatment of irradiated animals with injections of insulin resulted in a reduction in high blood glucose and the prolongation of survival time up to 5 days, which is comparable to the survival time when the cause of death is gastrointestinal. It is concluded that this radiation-induced diabetic syndrome resulted from acute necrosis of the cells of the islets of Langerhans, a previously unreported lethal effect of radiation in golden hamsters.

  9. Radiation-induced acute necrosis of the pancreatic islet and the diabetic syndrome in the golden hamster (Mesocricetus auratus)

    International Nuclear Information System (INIS)

    Exposure of golden hamsters to 35 000 rad of X-rays induced acute and specific necrosis of the cells of the islets of Langerhans of the pancreas within 4 hours, whereas no other tissue revealed any drastic changes which would lead to a critical illness until 36 hours. Animals began to show the characteristic signs of diabetes, that is, hyperglycaemia, hyperkalaemia, ketonemia, and acidosis at 12 hours and these continued until death, 56+-8 hours later. These were accompanied by the disappearance of β-cell granules and a decrease of plasma insulin. Treatment of irradiated animals with injections of insulin resulted in a reduction in high blood glucose and the prolongation of survival time up to 5 days, which is comparable to the survival time when the cause of death is gastrointestinal. It is concluded that this radiation-induced diabetic syndrome resulted from acute necrosis of the cells of the islets of Langerhans, a previously unreported lethal effect of radiation in golden hamsters. (author)

  10. Cocaine- and amphetamine-regulated transcript: a novel regulator of energy homeostasis expressed in a subpopulation of pancreatic islet cells.

    Science.gov (United States)

    Gilon, Patrick

    2016-09-01

    Type 2 diabetes is characterised by chronic hyperglycaemia and its incidence is highly increased by exaggerated food consumption. It results from a lack of insulin action/production, but growing evidence suggests that it might also involve hyperglucagonaemia and impaired control of glucose homeostasis by the brain. In recent years, the cocaine and amphetamine-regulated transcript (CART) peptides have generated a lot of interest in the battle against obesity because, via the brain, they exert anorexic effects and they increase energy expenditure. They are also localised, outside the brain, in discrete regions of the body and play a hormonal role in controlling various functions. In this issue of Diabetologia, the Wierup group (doi: 10.1007/s00125-016-4020-6 ) shows that CART peptides are expressed heterogeneously in islet cells of various species, including humans, and that their expression is upregulated in diabetes. The authors also shine a spotlight on some interesting effects of CART peptides on islet function, including stimulation of insulin secretion and inhibition of glucagon release. CART peptides would thus be at the centre of a cooperation between the brain and the endocrine pancreas to control glucose homeostasis. Although the mechanisms of action of CART peptides remain enigmatic because no specific receptor for these peptides has so far been discovered, their potential therapeutic use is evident and represents a new challenge for future research. PMID:27421727

  11. Sex differences between APPswePS1dE9 mice in A-beta accumulation and pancreatic islet function during the development of Alzheimer's disease.

    Science.gov (United States)

    Li, Xin; Feng, Ying; Wu, Wei; Zhao, Jia; Fu, Chunmei; Li, Yang; Ding, Yangnan; Wu, Binghuo; Gong, Yanju; Yang, Guizhi; Zhou, Xue

    2016-08-01

    The pathogenesis of Alzheimer's disease (AD), a type of neurodegenerative disease characterized by learning and memory impairment, is often associated with pathological features, such as amyloid-beta (Aβ) accumulation and insulin resistance. The transgenic mouse, APPswePS1dE9 (APP/PS1), is one of the most commonly used animal models in pathogenesis studies of AD. The purpose of this study is to investigate the sex differences between APP/PS1 mice in the pathogenesis of AD. The impairment of glucose and insulin tolerance was found to develop earlier in male APP/PS1 mice than in females. Plasma insulin levels were significantly decreased in male APP/PS1 mice, while total cholesterol levels in male APP/PS1 mice were higher than those in females. Triglyceride levels in male mice in both the wild-type (WT) and APP/PS1 groups were higher than in their female littermates. Soluble and insoluble Aβ levels in female APP/PS1 mouse brains were higher than those in males. And the learning and memorizing abilities of female APP/PS1 mice were poorer than those of males. Our results concluded that there were sex differences in Aβ formation, pancreatic islet function and insulin sensitivity between male and female APP/PS1 mice during the pathogenesis of AD. PMID:26519428

  12. Carbonyl stress-induced 5-hydroxytriptamine secretion from RIN-14B, rat pancreatic islet tumor cells, via the activation of transient receptor potential ankyrin 1.

    Science.gov (United States)

    Suzawa, Sayaka; Takahashi, Kenji; Shimada, Takahisa; Ohta, Toshio

    2016-07-01

    Methylglyoxal (MG), a highly reactive dicarbonyl substance, is known as an endogenous carbonyl stress-inducing substance related to various disease states. Irritable bowel syndrome (IBS) is one of the most frequently encountered gastrointestinal disorders and MG is considered to be its causal substance. An increased serum 5-hydroxytryptamine (5-HT) level is related to IBS symptoms and the majority of 5-HT originates from enterochromaffin (EC) cells in the intestine. Here we examine the mechanisms of MG-induced 5-HT secretion using RIN-14B cells derived from a rat pancreatic islet tumor since these cells are used as a model for EC cells. MG increased the intracellular Ca(2+) concentration ([Ca(2+)]i) and 5-HT secretion, both of which were inhibited by the removal of extracellular Ca(2+) and specific transient receptor potential ankyrin 1 (TRPA1) antagonists. MG elicited an inward current under voltage-clamped conditions. Prior application of MG evoked reciprocal suppression of subsequent [Ca(2+)]i responses to allylisothiocyanate, a TRPA1 agonist, and vice versa. Glyoxal, an analog of MG, also evoked [Ca(2+)]i and secretory responses but its potency was much lower than that of MG. The present results suggest that MG promotes 5-HT secretion through the activation of TRPA1 in RIN-14B cells. These results may indicate that TRPA1 is a promising target for the treatment of IBS and that the RIN-14B cell line is a useful model for investigation of IBS. PMID:27423812

  13. Pancreatitis

    Science.gov (United States)

    ... the hormones insulin and glucagon into the bloodstream. Pancreatitis is inflammation of the pancreas. It happens when digestive enzymes start digesting the pancreas itself. Pancreatitis can be acute or chronic. Either form is ...

  14. Pancreatitis

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    970359 CT diagnosis of pancreatic carcinoma andchronic pancreatitis. LUAN Baoqing(栾宝庆), et al,Dept Radiol, Beijing Friendship Hosp, Capital Med U-niv, Beijing, 100050. Chin J Radiol 1997; 31(2): 114-118. Objective: To improve the diagnostic accuracy ofpancreatic carcinoma and chronic pancreatitis. Materi-

  15. Pancreatitis

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    950347 Pancreatic endorcine response to parenteralnutrition in experimental acute pancreatitis.SUN Xi-aoguang(孙晓光),et al.Dept Nucl Med,ZhongshanHosp,Shanghai Med Univ,Shanghai.Shanghai Med J1995;18(2),74-70.In order to study the pancreatic endocrine responseto parenteral nutrition (PN) in acute pancreatitis,thedisease was induced in dogs by injecting 4% tauro-cholate sodium 0.5ml/kg plus trypsin 0.5mg/kg into the pancreatic duct.Intravenous infusion of PN wasinitiated one hour after the establishment of the dis-

  16. Islet transplantation in rodents: do encapsulated islets really work?

    Directory of Open Access Journals (Sweden)

    Yngrid Ellyn Dias Maciel de Souza

    2011-06-01

    Full Text Available CONTEXT: Diabetes mellitus type I affects around 240 million people in the world and only in the USA 7.8% of the population. It has been estimated that the costs of its complications account for 5% to 10% of the total healthcare spending around the world. According to World Health Organization, 300 million people are expected to develop diabetes mellitus by the year 2025. The pancreatic islet transplantation is expected to be less invasive than a pancreas transplant, which is currently the most commonly used approach. OBJECTIVES: To compare the encapsulated and free islet transplantation in rodents looking at sites of islet implantation, number of injected islets, viability and immunosuppression. METHODS: A literature search was conducted using MEDLINE/PUBMED and SCIELO with terms about islet transplantation in the rodent from 2000 to 2010. We found 2,636 articles but only 56 articles from 2000 to 2010 were selected. RESULTS: In these 56 articles used, 34% were encapsulated and 66% were nonencapsulated islets. Analyzing both types of islets transplantation, the majority of the encapsulated islets were implanted into the peritoneal cavity and the nonencapsulated islets into the liver, through the portal vein. In addition, the great advantage of the peritoneal cavity as the site of islet transplantation is its blood supply. Both vascular endothelial cells and vascular endothelial growth factor were used to stimulate angiogenesis of the islet grafts, increasing the vascularization rapidly after implantation. It also has been proven that there is influence of the capsules, since the larger the capsule more chances there are of central necrosis. In some articles, the use of immunosuppression demonstrated to increase the life expectancy of the graft. CONCLUSION: While significant progress has been made in the islets transplantation field, many obstacles remain to be overcome. Microencapsulation provides a means to transplant islets without

  17. Massive parallel gene expression profiling of RINm5F pancreatic islet beta-cells stimulated with interleukin-1beta

    DEFF Research Database (Denmark)

    Rieneck, K; Bovin, L F; Josefsen, K;

    2000-01-01

    derived from rat pancreatic beta-cells, before and after challenge with 30 and 1,000 pg/ml of recombinant human IL-1beta. The highest concentration resulted in decreased insulin production and cell death over a period of 4 days. Using three different time points, 2, 4 and 24 hours after challenge, we...... the genes into groups according to functional relations on the basis of knowledge of the structure or function ascribed to the individual genes. Many of the differentially regulated genes are known to play a role in immune- and stress-related pathways as well as in insulin secretion and vesicle trafficking...

  18. EFFECTS OF SERICIN ON GLUCOSE AND LIPID METABOLISM AND MORPHOLOGICAL STRUCTURES OF PANCREATIC ISLET%丝胶对2型糖尿病大鼠糖脂代谢及胰岛形态结构的影响

    Institute of Scientific and Technical Information of China (English)

    刘东波; 乔跃兵; 陈志宏

    2013-01-01

    Objective:To investigate the effects of sericin on glucose and lipid metabolism and morphological structures of pancreatic islet. Methods:48 male SD rats were randomly divided into normal control group, diabetes mellitus model group, sericin treatment group and metformin group, with 12 rats in each group. The diabetes mellitus rat’s model was established by continuously injecting streptozotocin into the peritoneal cavity. After the rat’s model was successfully established, the rats in sericin treatment group and metformin group were respectively lavaged with sericin (2.4g/kg/d) and metformin (55.33mg/kg/d) for 35 days. The blood glucose and blood lipid of rats in each group were detected;HE staining was used to observe the morphological structures of pancreatic islet. Results:Compared with rats in model group, the blood glucose, triglyceride, total cholesterol, low density lipoprotein and free fatty acid of rats in sericin and metformin group decreased obviously, high density lipoprotein increased obviously (P<0.01). The pancreatic islet of rats in model group distributed sparse and uneven, the border was irregular, the cells of pancreatic islet decreased obviously. Compared with rats in model group, the morphological structure of pancreatic islet of rats in sericin group and metformin group improved obviously. Conclusions:Sericin can signiifcantly improve glucose and lipid metabolism and morphological structures of pancreatic islet of diabetes mellitus rats.%目的:探讨丝胶对2型糖尿病大鼠糖脂代谢和胰岛形态结构的影响。方法:雄性SD大鼠48只随机分为正常对照组、糖尿病模型组、丝胶治疗组和二甲双胍组,每组12只。腹腔注射链脲佐菌素建立糖尿病模型;待成模后,二甲双胍组、丝胶治疗组大鼠分别给予二甲双胍(55.33mg/kg/d)和丝胶(2.4g/kg/d)灌胃35d。检测各组大鼠的血糖和血脂,HE染色观察胰岛的形态结构。结果:与模型组大鼠相比,丝

  19. Islet Neogenesis Associated Protein (INGAP) induces the differentiation of an adult human pancreatic ductal cell line into insulin-expressing cells through stepwise activation of key transcription factors for embryonic beta cell development.

    Science.gov (United States)

    Assouline-Thomas, Béatrice; Ellis, Daniel; Petropavlovskaia, Maria; Makhlin, Julia; Ding, Jieping; Rosenberg, Lawrence

    2015-01-01

    Regeneration of β-cells in diabetic patients is an important goal of diabetes research. Islet Neogenesis Associated Protein (INGAP) was discovered in the partially duct-obstructed hamster pancreas. Its bioactive fragment, pentadecapeptide 104-118 (INGAP-P), has been shown to reverse diabetes in animal models and to improve glucose homeostasis in patients with diabetes in clinical trials. Further development of INGAP as a therapy for diabetes requires identification of target cells in the pancreas and characterization of the mechanisms of action. We hypothesized that adult human pancreatic ductal cells retain morphogenetic plasticity and can be induced by INGAP to undergo endocrine differentiation. To test this hypothesis, we treated the normal human pancreatic ductal cell line (HPDE) with either INGAP-P or full-length recombinant protein (rINGAP) for short-term periods. Our data show that this single drug treatment induces both proliferation and transdifferentiation of HPDE cells, the latter being characterized by the rapid sequential activation of endocrine developmental transcription factors Pdx-1, Ngn3, NeuroD, IA-1, and MafA and subsequently the expression of insulin at both the mRNA and the protein levels. After 7 days, C-peptide was detected in the supernatant of INGAP-treated cells, reflecting their ability to secrete insulin. The magnitude of differentiation was enhanced by embedding the cells in Matrigel, which led to islet-like cluster formation. The islet-like clusters cells stained positive for nuclear Pdx-1 and Glut 2 proteins, and were expressing Insulin mRNA. These new data suggest that human adult pancreatic ductal cells retain morphogenetic plasticity and demonstrate that a short exposure to INGAP triggers their differentiation into insulin-expressing cells in vitro. In the context of the urgent search for a regenerative and/or cellular therapy for diabetes, these results make INGAP a promising therapeutic candidate. PMID:26558987

  20. What is the origin of pancreatic adenocarcinoma?

    Directory of Open Access Journals (Sweden)

    Pandey Krishan K

    2003-01-01

    Full Text Available Abstract The concept of pancreatic cancer origin is controversial. Acinar, ductal or islet cells have been hypothesized as the cell of origin. The pros and cons of each of these hypotheses are discussed. Based on the world literature and recent observations, pancreatic cells seem to have potential for phenotypical transdifferentiation, i.e ductal-islet, ductal-acinar, acinar-ductal, acinar-islet, islet-acinar and islet-ductal cells. Although the possibility is discussed that cancer may arise from either islet, ductal or acinar cells, the circumstances favoring the islet cells as the tumor cell origin include their greater transdifferentiation potency into both pancreatic and extrapancreatic cells, the presence of a variety of carcinogen-metabolizing enzymes, some of which are present exclusively in islet cells and the growth factor-rich environment of islets.

  1. Impaired pancreatic polypeptide response to a meal in type 1 diabetic patients: vagal neuropathy or islet cell dysfunction?

    DEFF Research Database (Denmark)

    Rasmussen, M H; Carstensen, H; List, S;

    1993-01-01

    The pancreatic polypeptide (PP) response to a mixed meal was investigated in seven insulin-dependent diabetics without measurable signs of diabetic autonomic neuropathy, and in seven healthy subjects. Since acute changes in metabolic regulation might influence the meal-induced PP response...... is independent of short-term changes in metabolic control. Since the response was attenuated in the insulin-dependent diabetic patients, who had no otherwise measurable signs of neuropathy, the PP response to a meal could be a sensitive indicator of dysfunction of the reflex arc controlling PP secretion......, the insulin-dependent diabetic patients were studied during normo- and hyperglycemic experimental conditions at blood glucose levels of 5 and 15 mmol/l, respectively. The PP response was identical on the two occasions, the response being significantly smaller than in the healthy subjects. Thus, PP response...

  2. Pancreatitis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010355 Oxymatrine enhances the expression of collagen I and α-SMA in rat chronic pancreatitis. WANG Yuliang(王昱良),et al. Dept Gastroenterol ,Huanghe Hosp,Sanmenxia 472000. World Chin J Digestol 2010;18(13):1331-36. Objective To investigate the treatment effects of oxymatrine (OM) against chronic pancreatitis in rats and to explore the potential

  3. Though active on RINm5F insulinoma cells and cultured pancreatic islets, recombinant IL-22 fails to modulate cytotoxicity and disease in a protocol of streptozotocin-induced experimental diabetes.

    Directory of Open Access Journals (Sweden)

    Anika eBerner

    2016-01-01

    Full Text Available Interleukin (IL-22 is a cytokine displaying tissue protective and pro-regenerative functions in various preclinical disease models. Anti-bacterial, pro-proliferative, and anti-apoptotic properties mediated by activation of the transcription factor signal transducer and activator of transcription (STAT-3 are key to biological functions of this IL-10 family member. Herein, we introduce RINm5F insulinoma cells as rat ß-cell line that, under the influence of IL-22, displays activation of STAT3 with induction of its downstream gene targets Socs3, Bcl3, and Reg3ß. In addition, IL-22 also activates STAT1 in this cell type. To refine those observations, IL-22 biological activity was evaluated using ex vivo cultivated murine pancreatic islets. In accord with data on RINm5F cells, islet exposure to IL-22 activated STAT3 and upregulation of STAT3-inducible Socs3, Bcl3, and STEAP4 was evident under those conditions. As these observations supported the hypothesis that IL-22 may exert protective functions in toxic ß-cell injury, application of IL-22 was investigated in murine multiple-low-dose streptozotocin (STZ-induced diabetes. For that purpose, recombinant IL-22 was administered thrice either immediately before and at disease onset (at d4, d6, d8 or closely thereafter (at d8, d10, d12. These two IL-22-treatment periods coincide with two early peaks of ß-cell injury detectable in this model. Notably, none of the two IL-22-treatment strategies affected diabetes incidence or blood glucose levels in STZ-treated mice. Moreover, pathological changes in islet morphology analyzed 28 days after disease induction were not ameliorated by IL-22 administration. Taken together, despite being active on rat RINm5F insulinoma cells and murine pancreatic islets, recombinant IL-22 fails to protect pancreatic ß-cells in the tested protocols from toxic effects of STZ and thus is unable to ameliorate disease in the widely used model of STZ-induced diabetes.

  4. Effects of Sericin Pretreatment on the Expression of Pancreatic Islet Cell Proteins in Diabetes Rats%丝胶预处理对糖尿病大鼠胰岛细胞蛋白表达的影响

    Institute of Scientific and Technical Information of China (English)

    付秀美; 薛景凤; 付文亮; 陈志宏

    2012-01-01

    Objective To investigate the effects of sericin pretreatment on the expression of Bax, Bcl-2, insulin and neuropeptide Y (NPY) protein of pancreatic islet cells in diabetes rats. Methods Thirty six SD rats were randomly divided into 3 groups:normal group,model group and sericin group. Model group and sericin group were established by intraperitoneally injection of streptozotocin (STZ). Blood glucose (BG)≥16.7 mmol/L was taken as the standard of successful modelization. The rats in sericin group were lavaged with sericin for 35 days before STZ injection. The enzymic method was used to measure BG. The expressions of Bax and Bcl-2 protein in the pancreas were observed by Western blot. The expressions of insulin and NPY protein in the pancreatic islet cells were detected by immunohistochemical staining. Results Compared with rats in model group,rats in sericin group had significantly reduced BG,Bax and NPY expressions in the pancreatic islet cells (P < 0.01) ;on the other hand,Bcl-2 and insulin expressions in the pancreatic islet cells of the sericin group increased obviously (P < 0.01). Conclusion Sericin pretreatment can inhibit the apoptosis of pancreatic islet β cells,up-regulate insulin protein and down-regulate NPY protein, which finally leads to satisfactory apotropaic effects on the diabetes rats.%目的 观察彩色蚕茧提取物——丝胶对糖尿病大鼠胰岛细胞Bax、Bcl-2、胰岛素及神经肽Y(NPY)蛋白表达的影响.方法 将36只SD大鼠随机分为正常组、模型组和丝胶组.模型组和丝胶组大鼠均建立链脲佐菌素(STZ)糖尿病动物模型,丝胶组于注射STZ前给予丝胶灌胃35 d.采用酶法检测血糖,免疫印记法观察Bax、Bcl-2蛋白的表达,免疫组化法观察胰岛素、NPY蛋白的表达.结果 与模型组大鼠相比,丝胶组大鼠血糖、Bax和NPY蛋白表达明显降低(P<0.01),Bcl-2和胰岛素蛋白表达明显升高(P<0.01).结论 丝胶预处理可抑制胰岛β细胞凋亡,上调胰

  5. The role of islet neogenesis-associated protein (INGAP) in islet neogenesis.

    Science.gov (United States)

    Lipsett, Mark; Hanley, Stephen; Castellarin, Mauro; Austin, Emily; Suarez-Pinzon, Wilma L; Rabinovitch, Alex; Rosenberg, Lawrence

    2007-01-01

    Islet Neogenesis-Associated Protein (INGAP) is a member of the Reg family of proteins implicated in various settings of endogenous pancreatic regeneration. The expression of INGAP and other RegIII proteins has also been linked temporally and spatially with the induction of islet neogenesis in animal models of disease and regeneration. Furthermore, administration of a peptide fragment of INGAP (INGAP peptide) has been demonstrated to reverse chemically induced diabetes as well as improve glycemic control and survival in an animal model of type 1 diabetes. Cultured human pancreatic tissue has also been shown to be responsive to INGAP peptide, producing islet-like structures with function, architecture and gene expression matching that of freshly isolated islets. Likewise, studies in normoglycemic animals show evidence of islet neogenesis. Finally, recent clinical studies suggest an effect of INGAP peptide to improve insulin production in type 1 diabetes and glycemic control in type 2 diabetes.

  6. Human islets and dendritic cells generate post-translationally modified islet autoantigens.

    Science.gov (United States)

    McLaughlin, R J; de Haan, A; Zaldumbide, A; de Koning, E J; de Ru, A H; van Veelen, P A; van Lummel, M; Roep, B O

    2016-08-01

    The initiation of type 1 diabetes (T1D) requires a break in peripheral tolerance. New insights into neoepitope formation indicate that post-translational modification of islet autoantigens, for example via deamidation, may be an important component of disease initiation or exacerbation. Indeed, deamidation of islet autoantigens increases their binding affinity to the T1D highest-risk human leucocyte antigen (HLA) haplotypes HLA-DR3/DQ2 and -DR4/DQ8, increasing the chance that T cells reactive to deamidated autoantigens can be activated upon T cell receptor ligation. Here we investigated human pancreatic islets and inflammatory and tolerogenic human dendritic cells (DC and tolDC) as potential sources of deamidated islet autoantigens and examined whether deamidation is altered in an inflammatory environment. Islets, DC and tolDC contained tissue transglutaminase, the key enzyme responsible for peptide deamidation, and enzyme activity increased following an inflammatory insult. Islets treated with inflammatory cytokines were found to contain deamidated insulin C-peptide. DC, heterozygous for the T1D highest-risk DQ2/8, pulsed with native islet autoantigens could present naturally processed deamidated neoepitopes. HLA-DQ2 or -DQ8 homozygous DC did not present deamidated islet peptides. This study identifies both human islets and DC as sources of deamidated islet autoantigens and implicates inflammatory activation of tissue transglutaminase as a potential mechanism for islet and DC deamidation. PMID:26861694

  7. Comprehensive alpha, beta and delta cell transcriptomes reveal that ghrelin selectively activates delta cells and promotes somatostatin release from pancreatic islets

    Directory of Open Access Journals (Sweden)

    Michael R. DiGruccio

    2016-07-01

    Conclusions: These results offer a straightforward explanation for the well-known insulinostatic actions of ghrelin. Rather than engaging beta cells directly, ghrelin engages delta cells to promote local inhibitory feedback that attenuates insulin release. These findings illustrate the power of our approach to resolve some of the long-standing conundrums with regard to the rich feedback that occurs within the islet that is integral to islet physiology and therefore highly relevant to diabetes.

  8. Bone mononuclear cells and pancreatic islets allograft in the treatment of diabetic rats%异体大鼠骨髓单个核细胞胰岛细胞移植治疗糖尿病

    Institute of Scientific and Technical Information of China (English)

    韩玮; 王云海; 王太成; 陈启龙

    2010-01-01

    Objective To study the curative effect of bone marrow mononuclear cells and pancreatic islets transplantation through the approach of the liver and tail vein. Methods The pancreatic islets and bone marrow mononuclear cells were isolated by discontinuous gradients centrifugation. Twenty-eight diabetic rats were randomly divided into groups A, B, C, and D. The rats in group A received 1000 pancreatic islets transplantation beneath the liver capsule, those in group B received transplantation of pancreatic islets and 1 × 107 bone marrow mononuclear cells beneath the liver capsule, those in group C received transplantation of 1000 pancreatic islets through the tail vein, and those in group D received transplantation of 1000 pancreatic islets and 1 × 107 bone marrow mononuclear cells through the tail vein. Plasma glucose level was determined at different time points. The effectiveness of combined different cells and transplantation approaches was compared. Results The blood glucose levels in groups A and B started to decrease in 3 days after transplantation. The blood glucose level in group A could be reduced to the normal level (7. 98 ±2. 28) mmol/L and maintain (3.71 ±0. 95) days, and that in group B could be reduced to (7. 72 ±1.75) mmol/L and maintain (4. 86 ± 1.06) days. The blood glucose level in groups C and D started to decrease in 4 days after transplantation. The blood glucose level in group C could be reduced to (7. 35 ±1.40) mmol/L and maintain (7. 85 ± 1.46) days, and that in group D to (7.00 ± 0. 83 ) mmol/L and maintain ( 14. 10 ± 1.21 ) days. There was statistically significant difference in blood glucose level among all groups ( P < 0. 05 ). Conclusion Transplantation of pancreatic islets combined with mononuclear cells through the tail vein in rats maintains the normal plasma glucose level for the longest duration. The plasma glucose level is ideal.%目的 观察异体骨髓单个核细胞和胰岛细胞通过肝脏和静脉途径移植后

  9. Pancreatitis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    2008318 Proteomics of hyperlipidemia-associated pancreatitis using differential gel electrophoresis and tandem mass spectrometry: experiment with rats. ZHANG Wei(张伟), et al. Dept Gastroenterol, Shanghai 1st Hosp, Shanghai Jiaotong Univ, Shanghai 200080. Natl Med J China 2008;88(16):1132-1131.Objective To analyze the injury mechanismof hyperlipidemia-associated acute pancreatitis utilizing pro-teomics.Methods Ten SD rats were fed with high fat feed to establish hyperlipidemic models,and 10 SD rats were fed with normal feed to be used as control group.

  10. 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 BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  11. 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.

  12. Improving cellular function and immune protection via layer-by-layer nanocoating of pancreatic islet β-cell spheroids cocultured with mesenchymal stem cells.

    Science.gov (United States)

    Bhaiji, Tasneem; Zhi, Zheng-Liang; Pickup, John C

    2012-06-01

    Islet transplantation as a therapy for type 1 diabetes is currently limited by lack of primary transplant material from human donors and post-transplantation loss of islets caused by adverse immune and nonimmune reactions. This study aimed to develop a novel strategy to create microenvironment for islets via integration of nanoencapsulation with cell cocultures, thereby enhancing their survival and function. The nanoencapsulation was achieved via layer-by-layer deposition of phosphorycholine-modified poly-L-lysine/heparin leading to the formation of nanometer-thick multilayer coating on islets. Spheroids formed by coculturing MIN6 β-cells with mesenchymal stem cells in suspension were used as the tool for testing encapsulation. Coculturing MSCs with MIN6 cells allowed the cell constructs to enhance structural and morphologic stability with improved insulin secretory function and render them less susceptible to inflammatory cytokine-induced apoptosis. Combining nanoencapsulation with coculture of MSCs/MIN6 resulted in higher glucose responsiveness, and lower antibody binding and apoptosis-inducing effects of cytokines. This strategy of nanoencapsulating islet cocultures appears promising to improve cellular delivery of insulin for treating type 1 diabetes. PMID:22447690

  13. Impairment of pancreatic islet β cell function induced by intermittent high glucose through oxidative and endoplasmic reticulum stress:experiment with rat pancreatic islet β cells%高糖波动诱导氧化应激及内质网应激损伤胰岛β细胞功能

    Institute of Scientific and Technical Information of China (English)

    侯志强; 李宏亮; 赵家军; 李光伟

    2008-01-01

    目的 评价波动性高糖对胰岛β细胞胰岛素合成及分泌功能,及对氧化应激和内质网应激的影响.方法 检测波动性(IHG)和持续性高糖(SHG)刺激后INS-1细胞合成及分泌胰岛素的功能,并测定细胞内过氧化物还原酶(PDX)-1、8-OHdG、NT及ATF-4等表达.结果 经过72 h孵育,IHG组INS-1细胞的胰岛素分泌指数明显低于SHG组(对照:1.67±0.23,SHG:1.31±0.04.IHG:0.64±O.11,P<0.05),且是时间依赖性的;IHG和SHG组较对照组细胞内胰岛素含量显著低[对照(12.37±0.37)μU/μg,SHG(11.08±0.03)μU/μg,IHG(10.91±0.14)μU/μg,P<0.05)],而且胰岛素和PDX-1的mRNA表达亦明显低;IHG组INS-1细胞较SHG组和对照组的8-OHdG、硝基酪氨酸含量以及ATF-4表达明显高.结论 波动性高糖较持续性高糖更能损伤胰岛β细胞功能,这与波动性高糖增高胰岛β细胞内氧化应激及内质网应激水平密切相关.%Objective To investigate the effect of intermittent hiigh shcese(IHG)on the pancreatic islet β-cell function and mechanism thereof.Methods Rat pancreatic islet β-cells of the line INS-1 were cultured and randomly divided into 3 groups:IHG group exposed to fluctuating concentrations of glucose,stable high glucose(SHG)group exposed to 16.7 mmoL/L glucose,and control group exposed to normal concentration(5.5 mmoL/L)glucose. 24,48,and 72 hours later radioimmunoassay wag used to detect the insulin secretion index(ISI).72 h later,the concentration of insulin in the cells wag detected with mdioimmunoassay.The contents of oxidative stress markers,nitrotyrosine(NT)and 8-hydroxy-2-deoxyguanosine(8-OHdG)were detected.Real-time PCR wag used to detect the mRNA expression of pemxiredoxin 1(PDX-1),ATF-4,one of the transcription factors of the family bZIP,and insulin.Western blotting wag used to detect the protein expression of ATF-4.Results The ISI of the IHG and SHG groups decreased time-dependently.The ISI of IHG and SHG groups were 0.64±0.1l and 1.31±0

  14. Enhanced expression of VEGF-A in β cells increases endothelial cell number but impairs islet morphogenesis and β cell proliferation

    OpenAIRE

    Cai, Qing; Brissova, Marcela; Reinert, Rachel B.; Pan, Fong Cheng; Brahmachary, Priyanka; Jeansson, Marie; Shostak, Alena; Radhika, Aramandla; Poffenberger, Greg; Quaggin, Susan E; Jerome, W. Gray; Daniel J Dumont; Alvin C Powers

    2012-01-01

    There is a reciprocal interaction between pancreatic islet cells and vascular endothelial cells (EC) in which EC-derived signals promote islet cell differentiation and islet development while islet cell-derived angiogenic factors promote EC recruitment and extensive islet vascularization. To examine the role of angiogenic factors in the coordinated development of islets and their associated vessels, we used a “tet-on” inducible system (mice expressing rat insulin promoter-reverse tetracycline...

  15. The Pancreas as an Islet Transplantation Site. Confirmation in a Syngeneic Rodent and Canine Autotransplant Model

    Directory of Open Access Journals (Sweden)

    John I Stagner

    2007-09-01

    Full Text Available Context The availability of islet transplantation is limited by both the number of donor pancreata and the number of islets required for successful transplantation. There is evidence that the liver presents a less than optimal environment for islets that contributes to short- and long-term beta cell destruction or failure. Objective It is our hypothesis that the pancreas is a suitable transplant site and may require fewer islets than standard sites such as the liver or kidney, and could lead to improvements in transplantation outcomes. Methods To test this hypothesis both a rodent and a canine model were used. Syngeneic rat islets were transplanted to the pancreas, liver, or kidney of Lewis rats. Fasting blood glucose levels were compared for three months as an index of islet function. Dogs received an islet autotransplant to a pancreatic remnant. Insulin and glucose concentrations were followed for six months. Results In the rat, normoglycemia was maintained with 600 islets transplanted in the pancreas in contrast to the liver (3,200 islets or kidney (1,000-2,000 islets. Dogs remained normoglycemic after receiving an intrapancreatic islet transplant (mean 7,640±3,600 islets. There was no evidence of pancreatitis or nutritional deficiency in either species. Conclusions The pancreas should be considered as an islet transplant site. The pancreas is the native milieu for islets, and offers the advantage of requiring fewer islets than other conventional sites, thereby increasing the possibility that one donor pancreas may serve one or more recipients.

  16. A Novel Efficient Technique of Pancreatic Islet Cell Isolation and Purification%一种高效的小鼠胰岛分离纯化新技术

    Institute of Scientific and Technical Information of China (English)

    李敏; 宋陆军; 高晓东; 常文举; 秦新裕

    2011-01-01

    Objective:To explore the method of obtaining enough mouse islets with high purity in order to set up an animal model for clinical islet transplantation.Methods: The 6~8 weeks male C57BL/6 mice weighing 25~30 g were intraperitoneal anesthetized before the operation of common bile duct ligation.Then we isolated and purified mice islets by adopting collagenV retro perfusion,situ digestion,gradient centrifugation in Ficoll-400 solution and sorted islets using sterile capillary pipettes in the phase contrast microscope.Islets purity was assessed by dithizone staining.Eventually, we cultured islet cells and observed the shape of islets on day 3, 8 and 24 separately.Results:From this way, we could obtain 390± 20 islets in each mouse.The isolated islets were round or mass, 50- 150 μm in diameter, complete and bright.The purity of the islets was more than 85%.Conclusions: We improve the method of isolating islets including retro perfusion,situ digestion and gradient centrifugation in Ficoll-400 solution, which is timesaving and effective.The cultured islet cells had high activity and formed single cells in petri dishes within 24 days, which is suitable for further study.%目的:探讨获得足够数量和较高纯度小鼠胰岛的分离及纯化方法,为进行小鼠的胰岛移植提供实验条件.方法:将6~8周,体质量25~30 g的雄性C57BL/6 小鼠腹腔麻醉后结扎胆总管,采用胶原酶Ⅴ逆行灌注、原位消化、Ficoll-400梯度离心并用无菌的毛细吸管在相差显微镜下观察并分选胰岛,双硫腙(DTZ)染色鉴定胰岛细胞.体外培养胰岛单细胞,并于第3、8、24天观察胰岛形态.结果:采用该法分离纯化后,每只小鼠可得到390±20个胰岛,胰岛呈圆形或团块状,直径50~150 μm,形态完整,折光性好,纯度达85%以上,24 d后在培养皿内铺成单个细胞.结论:本研究所用逆行灌注、原位消化及Ficoll-400梯度离心分离、纯化胰岛细胞的方法省时、高效,培养

  17. Glutamate (mGluR-5 gene expression in brain regions of streptozotocin induced diabetic rats as a function of age: role in regulation of calcium release from the pancreatic islets in vitro

    Directory of Open Access Journals (Sweden)

    Paulose CS

    2009-11-01

    Full Text Available Abstract Metabotrophic glutamate receptors (mGluRs modulate cellular activities involved in the processes of differentiation and degeneration. In this study, we have analysed the expression pattern of group-I metabotropic glutamate receptor (mGlu-5 in cerebral cortex, corpus striatum, brainstem and hippocampus of streptozotocin induced and insulin treated diabetic rats (D+I as a function of age. Also, the functional role of glutamate receptors in intra cellular calcium release from the pancreatic islets was studied in vitro. The gene expression studies showed that mGlu-5 mRNA in the cerebral cortex increased siginficantly in 7 weeks old diabetic rats whereas decreased expression was observed in brainstem, corpus striatum and hippocampus when compared to control. 90 weeks old diabetic rats showed decreased expression in cerebral cortex, corpus striatum and hippocampus whereas in brainstem the expression increased significantly compared to their respective controls. In 7 weeks old D+I group, mGlu-5 mRNA expression was significantly decreased in cerebral cortex and corpus striatum whereas the expression increased significantly in brainstem and hippocampus. 90 weeks old D+I group showed an increased expression in cerebral cortex, while it was decreased significantly in corpus striatum, brainstem and hippocampus compared to their respective controls. In vitro studies showed that glutamate at lower concentration (10-7 M stimulated calcium release from the pancreatic islets. Our results suggest that mGlu-5 receptors have differential expression in brain regions of diabetes and D+I groups as a function of age. This will have clinical significance in management of degeneration in brain function and memory enhancement through glutamate receptors. Also, the regulatory role of glutamate receptors in calcium release has immense therapeutic application in insulin secretion and function.

  18. 胰腺生长因子促胰岛β细胞的生物活性研究%Research on Bioactivity of Pancreatic Growth Factor in Hastening Prolification of Islet β RIN-m Cells

    Institute of Scientific and Technical Information of China (English)

    饶桂荣; 高梅; 陈光明; 张海松; 杨富强; 王洪敏

    2012-01-01

    目的 研究胰腺提取物中的胰腺生长因子对胰岛β细胞的增殖活性.方法 常规培养胰岛β细胞RIN-m细胞株,按每孔1.0×104个细胞入96孔板,加药培养分别至24 h、48 h、72 h,按四甲基偶氮唑蓝比色法(methyl thiazolyl tetrazolium,MTT)和5-溴脱氧尿嘧啶(5-Bromo-2’-Deoxyuridine,Brdu)法检测细胞生长增殖情况,设阴性对照,以市售百密达(BEYATTA)为阳性对照;同时采用反转录-聚合酶链反应(reverse transcription-polyrnerase chain reaction,RT-PCR)荧光定量检测RIN-m细胞内的肠胰十二指肠同源盒1(pancreatic duodenal homeobox factor-1,PDX-1)和胰岛素( insulin,INS)基因的表达情况;收集培养48h后的细胞,以流式细胞仪检测细胞的凋亡情况.结果 胰腺提取物中的胰腺生长因子能促进胰岛RIN-m细胞株的增殖,增殖率达40%以上(P<0.01),PDX-1和INS基因的同步高表达,均具有统计学差异(P<0.01).实验组与对照组相比,细胞凋亡率降低.结论 本胰腺提取物质( pancreatic extract,PE)有显著促进胰岛β细胞生长增殖、抑制其凋亡的作用,可作为糖尿病治疗新药开发重要依据.%Objective To study the proliferation activity of pancreatic growth factor from pancreatic extract on Islet (3 RIN-m cells. Methods RIN-m cells were cultured as usual and loaded into 96 well plate separately (1. 0 × 104 cells each). The buffers included different pancreatic extract (5 μg, 10 μg, 20 μg) were added and the cells were cultured for 24, 48 and 72 hours. Methyl thiazolyl tetrazolium (MTT) and Brdu techniques were used to investigated proliferation or growth of RIN-m cells. The negative and positive controls were assigned Reverse transcription-polymerase chain reaction (RT-PCR) technique was used to quantify the expression of pancreatic duodenal homeobox factor-1 (PDX-1) gene and insulin (INS) gene. Apoptosis of RIN-m cells was checked by flow cytometry. Results The RIN-m cell growth was stimulated at 24

  19. 铁超负荷诱导胰岛细胞凋亡机制的研究%Thestudy of mechanism on iron overload inducing apoptosis of pancreatic islet cells in the wistar rats

    Institute of Scientific and Technical Information of China (English)

    吕雪梅; 高赟; 杨波; 陈涛; 龙洋; 田浩明

    2012-01-01

    Objective To investigate the effect of iron overload on apoptosis of pancreatic islet cells in the Wistar rats. Methods Sixty-five male rats of the Wistar strain were divided randomly into four groups: Group A which received repeated in-traperitoneal injections of ferric nitrilotriacetate (FeNTA) , Group B which received the equivalent dose of disodic nitrilotriacetate, Group C which was injected i. p. Diethylenetriaminepentaacetic acid besides FeNTA and Group D that was untreated controls, respectively. Glucose tolerance tests were performed at the beginning and the 10th week. Serum iron and ferritin were measured after performing the intervention. The protein and mRNA expression of Caspase-3、PPAR-γ and NF-KB in pancreatic islets were assessed by immunohistochemistry and in situ hybridization, respectively. Results At 10 week, both the protein and mRNA expression of Caspase-3 as well as NF-KB were significantly higher in Group A than those of the other groups; the protein and mRNA expression of PPAR-γ in Group A were lower as compared with group B or group D; the apoptotic cells of islets in Group A were more than those in the other groups. Conclusion Iron overload may induce oxidative stress and NF-KB activation, inhibit the expression of PPAR-γ and lead to the increased expression of Caspase-3 in islet cells, which were involved in the apoptosis of islet cells.%目的 观察铁超负荷对Wistar大鼠胰岛细胞凋亡影响.方法 雄性Wistar大鼠65只随机分为四组:A组(铁干预组)、B组(次氮三乙酸二钠对照组)、C组(铁干预加去铁组)和D组(空白对照组).于实验开始、第10周时行腹腔注射葡萄糖耐量试验;10周后采血测血清铁、血清铁蛋白;针对NF-κB、PPAR-γ Caspase-3作免疫组织化学染色及核酸原位杂交.结果 A组胰岛中NF-κB、Caspase-3蛋白、NF-κB和Caspase-3 mRNA较其它三组明显增加(P<0.05);A组胰岛中PPAR-γ蛋白和mRNA较B组和D组明显减低(P<0.05);A组胰岛

  20. 简便快捷的小鼠胰岛分离纯化方法研究%A Convenient and Efficient Method of Mouse Pancreatic Islet Isolation and Purification

    Institute of Scientific and Technical Information of China (English)

    合湫; 苏恒; 李超; 沈涛; 严新民; 薛元明

    2012-01-01

    目的 探讨小鼠胰岛分离与纯化的方法.方法 采用多点注射灌注胶原酶法消化胰腺,不连续密度梯度离心联合人工挑取的方法分离、纯化胰岛.双硫腙特异性染色后计算胰岛产量及纯度.葡萄糖刺激后测定培养上清液胰岛素水平检测胰岛功能.结果 (1)每只小鼠采用上述分离、纯化法平均得到(114±15)个胰岛,平均纯度为(77.12±3.23)%,胰岛细胞存活率>90%; (2)分离、纯化的胰岛培养上清液中胰岛素水平在无糖、低糖(2.8 mmol/L)和高糖(22.2 mmol/L)刺激下分别为(23.80±3.52) mIU/L、 (67.57 ±4.04) mIU/L和(164.32±10.75) mIU/L,各组间比较,差异有统计学意义(P<0.05).两两比较,低糖组的胰岛素水平为无糖组的2.84倍(P< 0.05),高糖组的胰岛素水平为低糖组的2.43倍(P<0.05),高糖组的胰岛素水平为无糖组的6.90倍(P<0.05).结论 采用多点注射灌注胶原酶法消化胰腺,不连续密度梯度离心联合人工挑取的方法分离、纯化的小鼠胰岛产量及纯度较高,形态完整,不同浓度葡萄糖刺激后胰岛素分泌反应良好,是一种简便、快捷的小鼠胰岛分离方法.%Objective To investigate a convenient and efficient method of mouse pancreatic islets isolation and purification. Methods The isolation of mouse pancreatic islets was carried out by stationary digestion after multi-point injection of collagenase IV solution into the pancreas. A discontinuous Histopaque solution (1119, 1110, 1080 and 1060) was applied for the purification of the islets. Islet cell purity and viability were determined by dithizone ( DTZ) and Trypan blue staining. The islets were cultured overnight and stimulated with different concentration of glucose (0, 2.8 and 22.2mmol/L) for 1 hour. Supernatants were collected for insulin assays by an insulin RIA kit. Results (1) By this optimized islets isolation and purification protocol, each mouse pancreas could yield (114 ± 15) islets, with an

  1. 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.

  2. Filtration is a time-efficient option to Histopaque, providing good-quality islets in mouse islet isolation.

    Science.gov (United States)

    Ramírez-Domínguez, Miriam; Castaño, Luis

    2015-03-01

    Pancreatic islet transplantation is a promising therapy for Type I Diabetes. For many years the method used worldwide for islet purification in both rodent and human islet isolation has been Ficoll-based density gradients, such as Histopaque. However, it is difficult to purify islets in laboratories with staff limitations when large scale isolations are required. We hypothesized that filtration could be a more simple and fast alternative to obtain good quality islets. Four separate islet isolations were performed per method, comparing filtration and Histopaque purification with handpicking as the gold standard method for islet purity. Different parameters of quality were assessed: yield in number of islets per pancreas, purity by dithizone staining, viability by Fluorescein Diacetate/Propidium Iodide vital staining and in vitro functionality assessed by Glucose Stimulated Insulin Secretion. Time efficiency and cost were also analyzed. The overall quality of the islets obtained both by Histopaque and filtration was good. Filtration saved almost 90 % of the time consumed by Histopaque purification, and was also cheaper. However, one-third of the islets were lost. Since human and rodent islets share similar size but different density, filtration appears as a purification method with potential interest in translation to clinic. PMID:24443076

  3. 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.

  4. 胰腺导管上皮细胞转分化为胰岛样细胞%Transdifferentiation of mouse pancreatic ductal epithelial cells into islet-like cells

    Institute of Scientific and Technical Information of China (English)

    赵艳艳; 余勤; 李志臻; 秦贵军

    2010-01-01

    BACKGROUND: Islet transplantation is an effective method for the treatment of type 1 diabetes mellitus and parts of type 2 diabetes mellitus. However, its application is hindered by insufficient sources and immunologic rejection. Though transdifferentiation of pancreatic stem cells is at the starting step, it is thought to be the hopeful source for islet cell transplantation.OBJECTIVE: To look for a suitable cells-transplantation source for the treatment of diabetes mellitus. METHODS: The pancreatic ductal epithelial cells were separated from Kunming mice and cultured in DMEM/F12 medium supplemented with keratinocyte growth factor, hepatocyte growth factor and nicotinamide, etc. Samples were taken at different time points for light microscopy and electron microscope. The changes of CK-19 and PDX-1 were detected by immunocytochemistry at 1 and 16 days. The expressions of insulin and glucagon gene were detected by RT-PCR at 1 and 16 days. The physiologic function of these islet-like clusters was determined by dithizone staining and glucose stimulation at 21 days. RESULTS AND CONCLUSION: A large number of epitheliod cells were CK-19 immunoreactive positive and few of them were PDX-1 positive at 1 day after isolation, then CK-19 positive cells proliferated quickly and formed substantial plaques of epithelial cells in cobblestone pattern. At 16 days later, these cells begin to form islet-like clusters gradually, while most of them were PDX-1 immunoreactive positive. The analysis of mRNA by RT-PCR showed very low levels of insulin and glucagon mRNA in the starting materials but increase was found as the process of transdifferentiation. At 21 day differentiated islet-like clusters were stained red by dithizone. In those samples exposed to a stimulatory 15 mmol/L glucose, there was a 1.6-fold increase in insulin compared with to 5.6 mmol/L glucose (P < 0.05). Pancreatic ductal cells of adult Kunming mice could proliferate quickly and have the potency of

  5. CT features of nonfunctioning islet cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Eelkema, E.A.; Stephens, D.H.; Ward, E.M.; Sheedy, P.F. II

    1984-11-01

    To determine the computed tomographic (CT) characteristics of nonfunctioning islet cell carcinoma of the pancreas, the CT scans of 27 patients with that disease were reviewed. The pancreatic tumor was identified as a mass in 26 patients (96%) Of the 25 tumors evaluated with contrast enhancement, 20 became partially diffusely hyperdense relative to nearby normal pancreatic tissue. Hepatic metastases were identified in 15 patients (56%), regional lymphadenopathy in 10 (37%), atrophy of the gland proximal to the tumor in six (22%), dilatation of the biliary ducts in five (19%), and dilatation of the pancreatic duct in four (15%). The CT appearances of the nonfunctioning islet cell tumors were compared with those of 100 ordinary (ductal) pancreatic adenocarcinomas. Although the two types of tumors were sometimes indistinguishable, features found to be more characteristic of islet cell carcinoma included a pancreatic mass of unusually large size, calcification within the tumor, and contrast enhancement of either the primary tumor or hepatic metastases. Involvement of the celiac axis or proximal superior mesenteric artery was limited to ductal carcinoma.

  6. From islet cell transplantation to pancreatic stem cell transplantation in the treatment of diabetes%从胰岛细胞移植到胰腺干细胞移植,治愈糖尿病还有多远?★

    Institute of Scientific and Technical Information of China (English)

    王洪; 李金成; 李政; 孙海峰; 殷慧

    2013-01-01

      背景:胰岛细胞移植和胰腺干细胞移植是近年来糖尿病治疗的研究热点,也是治愈糖尿病最有希望的途径。  目的:探讨胰岛细胞移植和胰腺干细胞移植治疗糖尿病的可行性、优势、面临的问题及解决的办法。  方法:收集胰岛细胞移植和胰腺干细胞移植治疗糖尿病的相关实验和临床研究,进行实验数据分析两种细胞移植途径治疗糖尿病的影响因素,从细胞分子生物学水平认识胰岛细胞移植和胰腺干细胞移植治疗糖尿病的优势和缺点。  结果与结论:胰岛细胞移植治疗糖尿病受供体不足的制约,胰腺干细胞移植解决了胰岛细胞供体短缺的有效途径,但胰腺干细胞移植的研究还停留在动物实验阶段,需要进行广泛的临床研究。首先要明确胰腺干细胞的特异性标志物,其次要掌握将相关干细胞诱导分化为胰腺干细胞的方法和技术。%BACKGROUND:Islet cel transplantation and pancreatic stem cel transplantation are the research focus in the treatment of diabetes, and they are the most promising approaches. OBJECTIVE:To explore the feasibility, advantages, problems and solution methods of islet cel transplantation and pancreatic stem cel transplantation in the treatment of diabetes. METHODS:Relative experiments and clinical researches on islet cel transplantation and pancreatic stem cel transplantation for the treatment of diabetes were col ected to analyze the experimental data. The influencing factors of islet cel transplantation and pancreatic stem cel transplantation in the treatment of diabetes were analyzed, and the advantages and disadvantages of islet cel transplantation and pancreatic stem cel transplantation in the treatment of diabetes were studied from the cel levels and molecular biology. RESUTLS AND CONCLUSION:Islet cel transplantation for the treatment of diabetes is limited with donor shortage, while pancreatic

  7. From islet cell transplantation to pancreatic stem cell transplantation in the treatment of diabetes%从胰岛细胞移植到胰腺干细胞移植,治愈糖尿病还有多远?★

    Institute of Scientific and Technical Information of China (English)

    王洪; 李金成; 李政; 孙海峰; 殷慧

    2013-01-01

    BACKGROUND:Islet cel transplantation and pancreatic stem cel transplantation are the research focus in the treatment of diabetes, and they are the most promising approaches. OBJECTIVE:To explore the feasibility, advantages, problems and solution methods of islet cel transplantation and pancreatic stem cel transplantation in the treatment of diabetes. METHODS:Relative experiments and clinical researches on islet cel transplantation and pancreatic stem cel transplantation for the treatment of diabetes were col ected to analyze the experimental data. The influencing factors of islet cel transplantation and pancreatic stem cel transplantation in the treatment of diabetes were analyzed, and the advantages and disadvantages of islet cel transplantation and pancreatic stem cel transplantation in the treatment of diabetes were studied from the cel levels and molecular biology. RESUTLS AND CONCLUSION:Islet cel transplantation for the treatment of diabetes is limited with donor shortage, while pancreatic stem cel transplantation can solve the donor shortage, but the research on pancreatic stem cel transplantation is limited in animal experiments. Extensive clinical study can be conducted on the basis of the identification of specific markers of pancreatic stem cel s, as wel as the methods and techniques that can induce the relative stem cel s to differentiate into pancreatic stem cel s.%  背景:胰岛细胞移植和胰腺干细胞移植是近年来糖尿病治疗的研究热点,也是治愈糖尿病最有希望的途径。  目的:探讨胰岛细胞移植和胰腺干细胞移植治疗糖尿病的可行性、优势、面临的问题及解决的办法。  方法:收集胰岛细胞移植和胰腺干细胞移植治疗糖尿病的相关实验和临床研究,进行实验数据分析两种细胞移植途径治疗糖尿病的影响因素,从细胞分子生物学水平认识胰岛细胞移植和胰腺干细胞移植治疗糖尿病的优势和缺点。  

  8. Avascular necrosis of the femoral head presenting as trochanteric bursitis.

    OpenAIRE

    Mandell, B F

    1990-01-01

    Five patients are described with avascular necrosis of the femoral head who presented with ipsilateral trochanteric bursitis, in the absence of clearcut hip joint disease. Avascular necrosis was indicated by magnetic resonance imaging. It is suggested that clinical trochanteric bursitis, especially when refractory to local corticosteroid treatment, may be the initial sign of hip disease. In the patient with risk factor(s) for avascular necrosis that diagnosis should be considered and evaluate...

  9. Effect of gastric bypass surgery on fasting blood glucose and pancreatic islet cell in type 2 diabetic rats%胃旁路术对血糖及胰岛细胞的影响

    Institute of Scientific and Technical Information of China (English)

    史逸华; 郑志坚; 戴灵波

    2013-01-01

    Objective To study the effect and mechanism of gastric bypass surgery on type 2 diabetic rats.Methods The models of type 2 diabetic rats were induced by stretozotocin and 20 diabetic rats were randomly divided into 2 groups:diabetes-operation group (DO group,n =10)and diabetes-control group(DC group,n =10).20 normal rats were randomly divided into 2 groups:normal-operation(NO group,n =10) and normalcontrol group(NC group,n =10).Rats in DO and NO group underwent GBP and rats in DC group and NC group underwent sham operation.Fasting blood glucose(FBG) levels of rats in each group were detected before operation and on 72 h,1th week,4th week,8th week after operation.On the 8th week after operation,pancreas tissues were harvested for HE staining and immunofluorescence,histological changes observed.Results The FBG levels of rats were not statistically significant different before operation between DO group and DC group or between NO group and NC group (P > 0.05).After operation,the FBG levels of rats in DO group gradually declined (P < 0.05).FBG levels of rats in DO group were lower after operation than before operation(P <0.05) ; After operation FBG levels of rats were higher in DO group than in NO group and NC group at the same time point (P <0.05).In DC group,the difference of FBG levels of rats at different time point was not statistically significant(P > 0.05).The difference of FBG had no statistically significance between the different time points of the same group or between the same time point of different groups (P > 0.05).HE staining showed that,in DO group,newborn small islets appeared in pancreas which increased the number of islet.The new islets were smaller,mostly around the pancreatic duct and the structure was similar to that of the normal islets.Immunofluorescence staining also showed that the number of islets increased.Insulin immunofluorescence found more isolated small islets composed of two or three insulin positive cells.Insulin and

  10. Islet formation during the neonatal development in mice.

    Directory of Open Access Journals (Sweden)

    Kevin Miller

    Full Text Available The islet of Langerhans is a unique micro-organ within the exocrine pancreas, which is composed of insulin-secreting beta-cells, glucagon-secreting alpha-cells, somatostatin-secreting delta-cells, pancreatic polypeptide-secreting PP cells and ghrelin-secreting epsilon-cells. Islets also contain non-endocrine cell types such as endothelial cells. However, the mechanism(s of islet formation is poorly understood due to technical difficulties in capturing this dynamic event in situ. We have developed a method to monitor beta-cell proliferation and islet formation in the intact pancreas using transgenic mice in which the beta-cells are specifically tagged with a fluorescent protein. Endocrine cells proliferate contiguously, forming branched cord-like structures in both embryos and neonates. Our study has revealed long stretches of interconnected islets located along large blood vessels in the neonatal pancreas. Alpha-cells span the elongated islet-like structures, which we hypothesize represent sites of fission and facilitate the eventual formation of discrete islets. We propose that islet formation occurs by a process of fission following contiguous endocrine cell proliferation, rather than by local aggregation or fusion of isolated beta-cells and islets. Mathematical modeling of the fission process in the neonatal islet formation is also presented.

  11. Glucose-stimulated insulin secretion does not require activation of pyruvate dehydrogenase: impact of adenovirus-mediated overexpression of PDH kinase and PDH phosphate phosphatase in pancreatic islets.

    Science.gov (United States)

    Nicholls, Linda I; Ainscow, Edward K; Rutter, Guy A

    2002-03-01

    Glucose-stimulated increases in mitochondrial metabolism are generally thought to be important for the activation of insulin secretion. Pyruvate dehydrogenase (PDH) is a key regulatory enzyme, believed to govern the rate of pyruvate entry into the citrate cycle. We show here that elevated glucose concentrations (16 or 30 vs 3 mM) cause an increase in PDH activity in both isolated rat islets, and in a clonal beta-cell line (MIN6). However, increases in PDH activity elicited with either dichloroacetate, or by adenoviral expression of the catalytic subunit of pyruvate dehydrogenase phosphatase, were without effect on glucose-induced increases in mitochondrial pyridine nucleotide levels, or cytosolic ATP concentration, in MIN6 cells, and insulin secretion from isolated rat islets. Similarly, the above parameters were unaffected by blockade of the glucose-induced increase in PDH activity by adenovirus-mediated over-expression of PDH kinase (PDK). Thus, activation of the PDH complex plays an unexpectedly minor role in stimulating glucose metabolism and in triggering insulin release.

  12. Phlorizin treatment prevents the decrease in plasma insulin levels but not the progressive histopathological changes in the pancreatic islets during aging of Zucker diabetic fatty rats.

    NARCIS (Netherlands)

    Janssen, S.W.J.; Martens, G.J.M.; Sweep, C.G.J.; Span, P.N.; Verhofstad, A.A.J.; Hermus, A.R.M.M.

    2003-01-01

    A hallmark of Type 2 diabetes mellitus (T2DM) is chronic hyperglycemia, which is thought to play a role in pancreatic beta-cell failure. Here we investigated whether treatment of Zucker diabetic fatty (ZDF) rats, an animal model for T2DM, with the renal glucose transport inhibitor phlorizin could pr

  13. Involvement of a proapoptotic gene (BBC3) in islet injury mediated by cold preservation and rewarming.

    Science.gov (United States)

    Omori, Keiko; Kobayashi, Eiji; Komatsu, Hirotake; Rawson, Jeffrey; Agrawal, Garima; Parimi, Mounika; Oancea, Alina R; Valiente, Luis; Ferreri, Kevin; Al-Abdullah, Ismail H; Kandeel, Fouad; Takahashi, Masafumi; Mullen, Yoko

    2016-06-01

    Long-term pancreatic cold ischemia contributes to decreased islet number and viability after isolation and culture, leading to poor islet transplantation outcome in patients with type 1 diabetes. In this study, we examined mechanisms of pancreatic cold preservation and rewarming-induced injury by interrogating the proapoptotic gene BBC3/Bbc3, also known as Puma (p53 upregulated modulator of apoptosis), using three experimental models: 1) bioluminescence imaging of isolated luciferase-transgenic ("Firefly") Lewis rat islets, 2) cold preservation of en bloc-harvested pancreata from Bbc3-knockout (KO) mice, and 3) cold preservation and rewarming of human pancreata and isolated islets. Cold preservation-mediated islet injury occurred during rewarming in "Firefly" islets. Silencing Bbc3 by transfecting Bbc3 siRNA into islets in vitro prior to cold preservation improved postpreservation mitochondrial viability. Cold preservation resulted in decreased postisolation islet yield in both wild-type and Bbc3 KO pancreata. However, after culture, the islet viability was significantly higher in Bbc3-KO islets, suggesting that different mechanisms are involved in islet damage/loss during isolation and culture. Furthermore, Bbc3-KO islets from cold-preserved pancreata showed reduced HMGB1 (high-mobility group box 1 protein) expression and decreased levels of 4-hydroxynonenal (4-HNE) protein adducts, which was indicative of reduced oxidative stress. During human islet isolation, BBC3 protein was upregulated in digested tissue from cold-preserved pancreata. Hypoxia in cold preservation increased BBC3 mRNA and protein in isolated human islets after rewarming in culture and reduced islet viability. These results demonstrated the involvement of BBC3/Bbc3 in cold preservation/rewarming-mediated islet injury, possibly through modulating HMGB1- and oxidative stress-mediated injury to islets. PMID:27117005

  14. Experimental studies on islets isolation, purification and function in rats.

    Science.gov (United States)

    Pang, Xinlu; Xue, Wujun; Feng, Xinshun; Tian, Xiaohui; Teng, Yan; Ding, Xiaoming; Pan, Xiaoming; Guo, Qi; He, Xiaoli

    2015-01-01

    To develop a simple and effective method of islet isolation and purification in rats. Collagenase P was injected into pancreatic duct followed by incubation in water bath to digest the pancreas and isolate islet, then discontinuous gravity gradient purification was used to purify the islet. The purified islets were identified by dithizone staining. The viability of islets was assessed by fluorescence staining of acridine orange (AO) and propidium iodide (PI). The function of purified islets was determined by glucose-stimulated insulin release test and transplantation of rat with streptozocin-induced diabetes. 738±193 islets were recovered after purification. The average purity was 77±13%, the viability of islets was more than 95%. When inspected by glucose stimulation, the secreted insulin concentration was 24.31±5.47 mIU/L when stimulated by low concentration glucose and 37.62±4.29 mIU/L by high concentration glucose. There was significant difference between the two phases (Pmethod of injecting collagenase into pancreatic duct followed by incubation in water bath and purification using discontinuous gravity gradient. PMID:26885021

  15. IMPROVEMENT OF HUMAN ISLET FUNCTION BY ADENOVIRUS MEDIATED HO-1 GENE TRANSFER

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate in vitro heme oxygenase-1 gene (HO-1) delivery to human pancreatic islets by adenovirus vectors. Methods Recombinant adenovirus containing HO-1 or enhanced green fluorescent protein gene(EGFP) was generated by using the AdEasy System. The purified human pancreatic islets were infected with recombinant adenovirus vectors at various multiplicity of infection (MOI). Transduction was confirmed by fluorescence photographs and Western blot. Glucose-stimulated insulin secretion was detected by using Human insulin radioimmunoassay kits and was used to assess the function of human islets infected by recombinant adenovirus.Results Viral titers of Ad-hHO-1 and Ad-EGFP were 1.96×109 and 1.99×109 pfu/mL, respectively. Human pancreatic islets were efficiently infected by recombinant adenovirus vectors in vitro. Transfection of human islets at an MOI of 20 did not inhibit islet function. Recombinant adenovirus mediated HO-1gene transfer significantly improved the islet function of insulin release when simulated by high level glucose. Conclusion Recombinant adenovirus is efficient to deliver exogenous gene into human pancreatic islets in vitro. HO-1 gene transfection can improve human islet function.

  16. Biochemomechanical poroelastic theory of avascular tumor growth

    Science.gov (United States)

    Xue, Shi-Lei; Li, Bo; Feng, Xi-Qiao; Gao, Huajian

    2016-09-01

    Tumor growth is a complex process involving genetic mutations, biochemical regulations, and mechanical deformations. In this paper, a thermodynamics-based nonlinear poroelastic theory is established to model the coupling among the mechanical, chemical, and biological mechanisms governing avascular tumor growth. A volumetric growth law accounting for mechano-chemo-biological coupled effects is proposed to describe the development of solid tumors. The regulating roles of stresses and nutrient transport in the tumor growth are revealed under different environmental constraints. We show that the mechano-chemo-biological coupling triggers anisotropic and heterogeneous growth, leading to the formation of layered structures in a growing tumor. There exists a steady state in which tumor growth is balanced by resorption. The influence of external confinements on tumor growth is also examined. A phase diagram is constructed to illustrate how the elastic modulus and thickness of the confinements jointly dictate the steady state of tumor volume. Qualitative and quantitative agreements with experimental observations indicate the developed model is capable of capturing the essential features of avascular tumor growth in various environments.

  17. Numerical simulation of avascular tumor growth

    Energy Technology Data Exchange (ETDEWEB)

    Slezak, D Fernandez; Suarez, C; Soba, A; Risk, M; Marshall, G [Laboratorio de Sistemas Complejos, Departamento de Computacion, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (C1428EGA) Buenos Aires (Argentina)

    2007-11-15

    A mathematical and numerical model for the description of different aspects of microtumor development is presented. The model is based in the solution of a system of partial differential equations describing an avascular tumor growth. A detailed second-order numeric algorithm for solving this system is described. Parameters are swiped to cover a range of feasible physiological values. While previous published works used a single set of parameters values, here we present a wide range of feasible solutions for tumor growth, covering a more realistic scenario. The model is validated by experimental data obtained with a multicellular spheroid model, a specific type of in vitro biological model which is at present considered to be optimum for the study of complex aspects of avascular microtumor physiology. Moreover, a dynamical analysis and local behaviour of the system is presented, showing chaotic situations for particular sets of parameter values at some fixed points. Further biological experiments related to those specific points may give potentially interesting results.

  18. Developmental programming of polycystic ovary syndrome (PCOS): prenatal androgens establish pancreatic islet α/β cell ratio and subsequent insulin secretion.

    Science.gov (United States)

    Ramaswamy, S; Grace, C; Mattei, A A; Siemienowicz, K; Brownlee, W; MacCallum, J; McNeilly, A S; Duncan, W C; Rae, M T

    2016-01-01

    Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P = 0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P = 0.001), sustained into adolescence (P = 0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P = 0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P = 0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P = 0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells. PMID:27265420

  19. Developmental programming of polycystic ovary syndrome (PCOS): prenatal androgens establish pancreatic islet α/β cell ratio and subsequent insulin secretion

    Science.gov (United States)

    Ramaswamy, S.; Grace, C.; Mattei, A. A.; Siemienowicz, K.; Brownlee, W.; MacCallum, J.; McNeilly, A. S.; Duncan, W. C.; Rae, M. T.

    2016-01-01

    Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P = 0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P = 0.001), sustained into adolescence (P = 0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P = 0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P = 0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P = 0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells. PMID:27265420

  20. Early Metabolic Markers That Anticipate Loss of Insulin Independence in Type 1 Diabetic Islet Allograft Recipients

    OpenAIRE

    Hirsch, D; Odorico, J.; Danobeitia, J. S.; Alejandro, R; Rickels, M. R.; Hanson, M.; Radke, N.; Baidal, D.; Hullett, D.; Naji, A; Ricordi, C; Kaufman, D.; Fernandez, L.

    2012-01-01

    The objective of this study was to identify predictors of insulin independence and to establish the best clinical tools to follow patients after pancreatic islet transplantation (PIT). Sequential metabolic responses to intravenous (I.V.) glucose (I.V. glucose tolerance test [IVGTT]), arginine and glucose-potentiated argi-nine (glucose-potentiated arginine-induced insulin secretion [GPAIS]) were obtained from 30 patients. We determined the correlation between transplanted islet mass and islet ...

  1. Human Islet Amyloid Polypeptide

    DEFF Research Database (Denmark)

    Kosicka, Iga

    2014-01-01

    Diabetes mellitus type II is a metabolic disease affecting millions of people worldwide. The disease is associated with occurence of insoluble, fibrillar, protein aggregates in islets of Langerhans in the pancreas - islet amyloid. The main constituent of these protein fibers is the human islet...

  2. Effect of DPP-Ⅳ inhibitor combined with insulin intensive therapy on pancreatic islet repair%DPP-Ⅳ抑制剂联合胰岛素强化降糖治疗对胰岛修复的影响

    Institute of Scientific and Technical Information of China (English)

    区觉璋; 陈淑群; 黄泽

    2016-01-01

    Objective:To investigate the effect of DPP-Ⅳ inhibitor combined with insulin intensive therapy on pancreatic islet repair.Methods: 90 patients with newly diagnosed type 2 diabetic patients were randomly divided into observation group and control group, 45 cases in each group. The observation group were treated with subcutaneous injection of pre-mixed insulin before breakfast and dinner, setting target blood glucose value FBG 0.05). Atfer 12 weeks, the blood glucose level in the observation group was signiifcantly lower than that in the control group (t=1.756,t=2.369,P0.05). After treatment, the HOMA-β was signiifcantly higher in the observation group than that in the control group, and the level of HbA1C and HOMA-IR was signiifcantly lower than that in the control group (t=2.219,t=1.896,t=1.934,P0.05),治疗12周后,观察组患者血糖水平显著低于对照组患者(t=1.756,t=2.369,P0.05)。观察组患者治疗后HOMA-β显著高于对照组,且HbA1C、HOMA-IR水平显著低于对照组(t=2.219,t=1.896,t=1.934,P<0.05)。结论:DPP-Ⅳ抑制剂联合胰岛素强化降糖治疗可以更好地修复胰岛功能。

  3. The influence of porcine pancreas digestion parameters and islet histomorphology on islet isolation outcome.

    Science.gov (United States)

    Kinasiewicz, J; Sabat, M; Antosiak-Iwańska, M; Godlewska, E; Sitarek, E; Orłowski, T

    2011-01-01

    Transplantation of the pig islets of Langerhans is considered as the future treatment for patients suffering from type I diabetes mellitus. Despite the adaptation of modified Ricordi method and highly purified collagenase, the results of pancreas digestions are precarious. Selection of proper donor and optimal digestion procedure are fundamental. The aim of this study was to assess the impact of pancreas procuring parameters on pig islets yield. The pancreata were harvested from 69 market sows weighting over 150 kg. After intraductal injection of cold collagenase solution pancreata were transported in UW solution or under conditions of two layer method (TLM). In laboratory pancreata were digested at 37 degrees C according to Ricordi isolation method or stationary in the bottle. The particular parameters of isolation procedure were considered as substantial. Pig weight, volume of infused collagenase solution, TLM application and pancreas dividing before digestion positively affected islet yield. Additionally, the influence of pancreatic islet tissue histomorphology on isolation outcome was studied. Proper donor selection as well as adequate digestion parameters could improve pig islet recovery during islet isolation. PMID:21721406

  4. Expression and regulation of nampt in human islets.

    Directory of Open Access Journals (Sweden)

    Karen Kover

    Full Text Available Nicotinamide phosphoribosyltransferase (Nampt is a rate-limiting enzyme in the mammalian NAD+ biosynthesis of a salvage pathway and exists in 2 known forms, intracellular Nampt (iNampt and a secreted form, extracellular Nampt (eNampt. eNampt can generate an intermediate product, nicotinamide mononucleotide (NMN, which has been reported to support insulin secretion in pancreatic islets. Nampt has been reported to be expressed in the pancreas but islet specific expression has not been adequately defined. The aim of this study was to characterize Nampt expression, secretion and regulation by glucose in human islets. Gene and protein expression of Nampt was assessed in human pancreatic tissue and isolated islets by qRT-PCR and immunofluorescence/confocal imaging respectively. Variable amounts of Nampt mRNA were detected in pancreatic tissue and isolated islets. Immunofluorescence staining for Nampt was found in the exocrine and endocrine tissue of fetal pancreas. However, in adulthood, Nampt expression was localized predominantly in beta cells. Isolated human islets secreted increasing amounts of eNampt in response to high glucose (20 mM in a static glucose-stimulated insulin secretion assay (GSIS. In addition to an increase in eNampt secretion, exposure to 20 mM glucose also increased Nampt mRNA levels but not protein content. The secretion of eNampt was attenuated by the addition of membrane depolarization inhibitors, diazoxide and nifedipine. Islet-secreted eNampt showed enzymatic activity in a reaction with increasing production of NAD+/NADH over time. In summary, we show that Nampt is expressed in both exocrine and endocrine tissue early in life but in adulthood expression is localized to endocrine tissue. Enzymatically active eNampt is secreted by human islets, is regulated by glucose and requires membrane depolarization.

  5. Effect of different warm ischemic time on islet isolation and function in pigs

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming; DU Cheng-you

    2011-01-01

    Objective To study the effect of different warm-ischemia time on islet structure, yield and function. Methods Adult pigs were studied, and according to warm ischemic time (WIT, 0, 10, 20, 30, 45 min), the porcine pancreata were divided into 5 groups (A, B, C, D, and E group). The isolation of adult porcine pancreas was carried out by injection of Hanks into pancreatic duct and digestion with collagenase Ⅴ and Ⅰ. A discontinuous Ficoll 400 solution was applied for purifying islets. The structure, purity and viability of islets were determined by dithizone staining and AO/PI staining, and the function of islets was evaluated by the glucose stimulating insulin release test. Results There were little islets debris in group A, B and C. But it was very difficult to obtain integrate islets in group E. There was no significant difference between the groups of 0, 10 and 20 min in islet number before and after islet purification ( P > 0.05 ), while the difference was significant when warm ischemic time was prolonged to 30 min and 45 min ( P < 0. 01 ). In respect of islet function, the similar results were found in different groups. Conclusions When WIT is within 20 min, there is no deleterious effects on islet morphology and yield as well as function. However, when WIT is prolonged to 30 min, the loss in islet yield is severe, and the islet function is significantly impacted.

  6. Early over expression of messenger RNA for multiple genes, including insulin, in the Pancreatic Lymph Nodes of NOD mice is associated with Islet Autoimmunity

    Directory of Open Access Journals (Sweden)

    Eisenbarth George

    2009-10-01

    Full Text Available Abstract Background Autoimmune diabetes (T1D onset is preceded by a long inflammatory process directed against the insulin-secreting β cells of the pancreas. Deciphering the early autoimmune mechanisms represents a challenge due to the absence of clinical signs at early disease stages. The aim of this study was to identify genes implicated in the early steps of the autoimmune process, prior to inflammation, in T1D. We have previously established that insulin autoantibodies (E-IAA predict early diabetes onset delineating an early phenotypic check point (window 1 in disease pathogenesis. We used this sub-phenotype and applied differential gene expression analysis in the pancreatic lymph nodes (PLN of 5 weeks old Non Obese Diabetic (NOD mice differing solely upon the presence or absence of E-IAA. Analysis of gene expression profiles has the potential to provide a global understanding of the disease and to generate novel hypothesis concerning the initiation of the autoimmune process. Methods Animals have been screened weekly for the presence of E-IAA between 3 and 5 weeks of age. E-IAA positive or negative NOD mice at least twice were selected and RNAs isolated from the PLN were used for microarray analysis. Comparison of transcriptional profiles between positive and negative animals and functional annotations of the resulting differentially expressed genes, using software together with manual literature data mining, have been performed. Results The expression of 165 genes was modulated between E-IAA positive and negative PLN. In particular, genes coding for insulin and for proteins known to be implicated in tissue remodelling and Th1 immunity have been found to be highly differentially expressed. Forty one genes showed over 5 fold differences between the two sets of samples and 30 code for extracellular proteins. This class of proteins represents potential diagnostic markers and drug targets for T1D. Conclusion Our data strongly suggest that the

  7. Phase transition in tumor growth: I avascular development

    Science.gov (United States)

    Izquierdo-Kulich, E.; Rebelo, I.; Tejera, E.; Nieto-Villar, J. M.

    2013-12-01

    We propose a mechanism for avascular tumor growth based on a simple chemical network. This model presents a logistic behavior and shows a “second order” phase transition. We prove the fractal origin of the empirical logistics and Gompertz constant and its relation to mitosis and apoptosis rate. Finally, the thermodynamics framework developed demonstrates the entropy production rate as a Lyapunov function during avascular tumor growth.

  8. Human immunodeficiency virus and avascular necrosis of femur head:a case report

    Institute of Scientific and Technical Information of China (English)

    A.ATAHAN (C)A(G)ATAY; REYHAN K(UCU)KKAYA; MURAY AKYILDIZ; HANDE BERK; TANER YILDIRMAK; HALIT (O)ZS(U)T; HALUK ERAKSOY; SEMRA (C)ALANGU

    2004-01-01

    Avascular necrosis (AVN), also termed as osteonecrosis or aseptic necrosis, is a process caused by direct and indirect damage to the vascular supply of the involved bone.1-5 Clinical course of the disease is usually progressive and causes significant pain and limitation of movement. Trauma causes AVN by the obvious direct interruption of the vascular supply, but there are a variety of underlying systemic disorders associated with the development of AVN via indirect vascular compromise. The known risk factors include corticosteroid use, alcohol abuse, smoking, sickle cell anemia, coagulopathies, systemic lupus erythematosus, hypercholesterolemia, Gaucher ' s disease, chronic pancreatitis, and hyper-triglyceridemia.3 It is very difficult to define reasons of AVN in individual patient, because most of the patients had multiple risk factors for AVN. On the other hand, approximately 10%-20% of AVN cases have no known risk factors and are classified as idiopathic AVN.

  9. Pancreatic metastasis from mycosis fungoides mimicking primary pancreatic tumor.

    Science.gov (United States)

    Ceriolo, Paola; Fausti, Valentina; Cinotti, Elisa; Bonadio, Silvia; Raffaghello, Lizzia; Bianchi, Giovanna; Orcioni, Giulio Fraternali; Fiocca, Roberto; Rongioletti, Franco; Pistoia, Vito; Borgonovo, Giacomo

    2016-03-28

    Mycosis fungoides (MF) is a cutaneous T-cell lymphoma that can undergo local progression with possible systemic dissemination. We report a case of a patient affected by MF with a pancreatic mass that was a diagnostic challenge between primitive tumor and pancreatic metastasis from MF. Clinical setting findings and imaging studies raised the suspicion of a pancreatic primary neoplasm. A diagnostic clue was provided by the combined histomorphologic/immunohistochemical study of pancreatic and cutaneous biopsies, which revealed a pancreatic localization of MF. Considering the rarity of metastatic localization of MF to the pancreas, we next investigated whether chemokine-chemokine receptor interactions could be involved in the phenomenon to provide new insight into the possible mechanisms underlying metastatic localization of MF to the pancreas. Histological analyses of archival pancreatic tissue demonstrated that glucagon-secreting cells of the pancreatic islets expressed the CCL27 chemokine, which may have attracted in our case metastatic MF cells expressing the complementary receptor CCR10.

  10. OBSTACLES IN THE APPLICATION OF MICROENCAPSULATION IN ISLET TRANSPLANTATION

    NARCIS (Netherlands)

    DEVOS, P; WOLTERS, GHJ; FRITSCHY, WM; VANSCHILFGAARDE, R

    1993-01-01

    Several factors stand in the way of successful clinical transplantation of alginate-polylysine-alginate microencapsulated pancreatic islets. These obstacles can be classified into three categories. The first regards the technical aspects of the production process. Limiting factors are the insufficie

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

    Directory of Open Access Journals (Sweden)

    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

  12. MR imaging of pancreatic diseases

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Katsuyoshi E-mail: itokatsu@po.cc.yamaguchi-u.ac.jp; Koike, Shinji; Matsunaga, Naofumi

    2001-05-01

    This article presents current MR imaging techniques for the pancreas, and review a spectrum of MR imaging features of various pancreatic diseases. These include: 1) congenital anomalies such as anomalous union of pancreatobiliary ducts, divisum, and annular pancreas, 2) inflammatory diseases, including acute or chronic pancreatitis with complications, groove pancreatitis, and autoimmune pancreatitis, tumor-forming pancreatitis, 3) pancreatic neoplasms, including adenocarcinoma, islet cell tumors, and cystic neoplasms (microcystic adenoma, mucinous cystic neoplasms, and intraductal mucin-producing pancreatic tumor). Particular attention is paid to technical advances in MR imaging of the pancreas such as fat-suppression, MR pancreatography (single- or multi-slice HASTE), and thin-section 3D multiphasic contrast-enhanced dynamic sequences. Imaging characteristics that may lead to a specific diagnosis or narrow the differential diagnosis are also discussed.

  13. Islet Transplantation in Pediatric Patients: Current Indications and Future Perspectives.

    Science.gov (United States)

    Bertuzzi, Federico; Antonioli, Barbara; Tosca, Marta C; Galuzzi, Marta; Bonomo, Matteo; Marazzi, Mario; Colussi, Giacomo

    2016-01-01

    The first islet transplantation in diabetes mellitus was performed more than 20 years ago. Since then, clinical results have progressively improved. Nowadays, islet transplantation can be considered a real therapeutic option after pancreatectomy for painful chronic pancreatitis (autotransplantation) and in selected adult patients affected by type 1 diabetes mellitus (allotransplantation). Better results are mainly due to the advances in the standardization of islet isolation and purification procedures as well as in the pharmacological treatment of recipients. Anti-inflammatory treatments facilitate islet engraftment and prevent metabolic exhaustion and functional β-cell apoptosis; new strategies better control islet graft rejection. As a consequence, islet transplantation activities are no longer confined to few centers only, rather thousands of transplants are now performed all over the world. Many attempts are actually undertaken to find solutions to current problems of islets transplantation, from toxicity of immunosuppressive therapy to the limited engraftment, function and duration. There is general hope that these procedures will offer a safe and feasible therapeutic option for an increasing number of patients suffering from diabetes mellitus, including pediatric patients. PMID:26682915

  14. Important role of heparan sulfate in postnatal islet growth and insulin secretion

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Iwao; Noguchi, Naoya [Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Nata, Koji [Department of Medical Biochemistry, Iwate Medical University School of Pharmacy, Yahaba-cho 028-3603 (Japan); Yamada, Shuhei; Kaneiwa, Tomoyuki; Mizumoto, Shuji [Laboratory of Proteoglycan Signaling and Therapeutics, Hokkaido University Graduate School of Life Science, Sapporo 001-0021 (Japan); Ikeda, Takayuki [Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Sugihara, Kazushi; Asano, Masahide [Division of Transgenic Animal Science, Advanced Science Research Center, Kanazawa University, Kanazawa 920-8640 (Japan); Yoshikawa, Takeo [Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Yamauchi, Akiyo [Department of Biochemistry, Nara Medical University, Kashihara 634-8521 (Japan); Shervani, Nausheen Jamal; Uruno, Akira [Department of Advanced Biological Sciences for Regeneration (Kotobiken Medical Laboratories), Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Kato, Ichiro [Department of Biochemistry, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, Toyama 930-0194 (Japan); Unno, Michiaki [Department of Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8574 (Japan); Sugahara, Kazuyuki [Laboratory of Proteoglycan Signaling and Therapeutics, Hokkaido University Graduate School of Life Science, Sapporo 001-0021 (Japan); Takasawa, Shin [Department of Biochemistry, Nara Medical University, Kashihara 634-8521 (Japan); and others

    2009-05-22

    Heparan sulfate (HS) binds with several signaling molecules and regulates ligand-receptor interactions, playing an essential role in embryonic development. Here we showed that HS was intensively expressed in pancreatic islet {beta}-cells after 1 week of age in mice. The enzymatic removal of HS in isolated islets resulted in attenuated glucose-induced insulin secretion with a concomitant reduction in gene expression of several key components in the insulin secretion machinery. We further depleted islet HS by inactivating the exostosin tumor-like 3 gene specifically in {beta}-cells. These mice exhibited abnormal islet morphology with reduced {beta}-cell proliferation after 1 week of age and glucose intolerance due to defective insulin secretion. These results demonstrate that islet HS is involved in the regulation of postnatal islet maturation and required to ensure normal insulin secretion.

  15. Important role of heparan sulfate in postnatal islet growth and insulin secretion

    International Nuclear Information System (INIS)

    Heparan sulfate (HS) binds with several signaling molecules and regulates ligand-receptor interactions, playing an essential role in embryonic development. Here we showed that HS was intensively expressed in pancreatic islet β-cells after 1 week of age in mice. The enzymatic removal of HS in isolated islets resulted in attenuated glucose-induced insulin secretion with a concomitant reduction in gene expression of several key components in the insulin secretion machinery. We further depleted islet HS by inactivating the exostosin tumor-like 3 gene specifically in β-cells. These mice exhibited abnormal islet morphology with reduced β-cell proliferation after 1 week of age and glucose intolerance due to defective insulin secretion. These results demonstrate that islet HS is involved in the regulation of postnatal islet maturation and required to ensure normal insulin secretion.

  16. Pancreatic carcinoma coexisting with chronic pancreatitis versus tumor-forming pancreatitis: Diagnostic utility of the time-signal intensity curve from dynamic contrast-enhanced MR imaging

    Institute of Scientific and Technical Information of China (English)

    Yoshitsugu Tajima; Tamotsu Kuroki; Ryuji Tsutsumi; Ichiro Isomoto; Masataka Uetani; Takashi Kanematsu

    2007-01-01

    AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially pancreatic carcinoma coexisting with chronic pancreatitis and tumor-forming pancreatitis.METHODS: Forty-eight consecutive patients who underwent surgery for a focal pancreatic mass, including pancreatic ductal carcinoma (n = 33), tumor-forming pancreatitis (n = 8), and islet cell tumor (n = 7), were reviewed. Five pancreatic carcinomas coexisted with longstanding chronic pancreatitis. The pancreatic TICs were obtained from the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery, and were classified into 4 types according to the time to a peak: 25 s and 1, 2, and 3 min after the bolus injection of contrast material, namely, type-Ⅰ,Ⅱ,Ⅲ,and IV, respectively, and were then compared to the corresponding histological pancreatic conditions.RESULTS: Pancreatic carcinomas demonstrated type-m (n = 13) or IV (n = 20) TIC. Tumor-forming pancreatitis showed type-Ⅱ(n = 5) or Ⅲ(n = 3) TIC. All islet cell tumors revealed type-1. The type-IV TIC was only recognized in pancreatic carcinoma, and the TIC of carcinoma always depicted the slowest rise to a peak among the 3 pancreatic TICs measured in each patient, even in patients with chronic pancreatitis.CONCLUSION: Pancreatic TIC from dynamic MRI provides reliable information for distinguishing pancreatic carcinoma from other pancreatic masses, and may enable us to avoid unnecessary pancreatic surgery and delays in making a correct diagnosis of pancreatic carcinoma, especially, in patients with longstanding chronic pancreatitis.

  17. Corneal avascularity is due to soluble VEGF receptor-1.

    Science.gov (United States)

    Ambati, Balamurali K; Nozaki, Miho; Singh, Nirbhai; Takeda, Atsunobu; Jani, Pooja D; Suthar, Tushar; Albuquerque, Romulo J C; Richter, Elizabeth; Sakurai, Eiji; Newcomb, Michael T; Kleinman, Mark E; Caldwell, Ruth B; Lin, Qing; Ogura, Yuichiro; Orecchia, Angela; Samuelson, Don A; Agnew, Dalen W; St Leger, Judy; Green, W Richard; Mahasreshti, Parameshwar J; Curiel, David T; Kwan, Donna; Marsh, Helene; Ikeda, Sakae; Leiper, Lucy J; Collinson, J Martin; Bogdanovich, Sasha; Khurana, Tejvir S; Shibuya, Masabumi; Baldwin, Megan E; Ferrara, Napoleone; Gerber, Hans-Peter; De Falco, Sandro; Witta, Jassir; Baffi, Judit Z; Raisler, Brian J; Ambati, Jayakrishna

    2006-10-26

    Corneal avascularity-the absence of blood vessels in the cornea-is required for optical clarity and optimal vision, and has led to the cornea being widely used for validating pro- and anti-angiogenic therapeutic strategies for many disorders. But the molecular underpinnings of the avascular phenotype have until now remained obscure and are all the more remarkable given the presence in the cornea of vascular endothelial growth factor (VEGF)-A, a potent stimulator of angiogenesis, and the proximity of the cornea to vascularized tissues. Here we show that the cornea expresses soluble VEGF receptor-1 (sVEGFR-1; also known as sflt-1) and that suppression of this endogenous VEGF-A trap by neutralizing antibodies, RNA interference or Cre-lox-mediated gene disruption abolishes corneal avascularity in mice. The spontaneously vascularized corneas of corn1 and Pax6+/- mice and Pax6+/- patients with aniridia are deficient in sflt-1, and recombinant sflt-1 administration restores corneal avascularity in corn1 and Pax6+/- mice. Manatees, the only known creatures uniformly to have vascularized corneas, do not express sflt-1, whereas the avascular corneas of dugongs, also members of the order Sirenia, elephants, the closest extant terrestrial phylogenetic relatives of manatees, and other marine mammals (dolphins and whales) contain sflt-1, indicating that it has a crucial, evolutionarily conserved role. The recognition that sflt-1 is essential for preserving the avascular ambit of the cornea can rationally guide its use as a platform for angiogenic modulators, supports its use in treating neovascular diseases, and might provide insight into the immunological privilege of the cornea. PMID:17051153

  18. Avascular necrosis associated with nailing of femoral neck fracture

    International Nuclear Information System (INIS)

    Two patients with femoral neck fractures, one displaced and one undisplaced, are presented. Preoperative intravital staining with tetracycline and Tc-MDP scintimetry both showed intact femoral head circulation while Tc-MDP-scintimetry 1 week after operation showed pronounced circulatory deficiency. SR85-scintimetry performed at the same time was inconclusive. Segmental collapse was observed radiographically, 8 and 12 months postoperatively. The major vascular injury resulting in avascularity most probably occured during the procedure of osteosynthesis, and Tc-MDP-scintimetry was found suitable for early postoperative recognition of avascular necrosis in both fractures. (author)

  19. Long-term graft function of cryostored alginate encapsulated rat islets

    Directory of Open Access Journals (Sweden)

    Schneider Stephan

    2011-09-01

    Full Text Available Abstract Microencapsulation of pancreatic islets before transplantation is a promising approach to enable graft function in an immunocompetent recipient without immunosuppression. However, the insufficient availability of allogenic islet tissue is a major problem. One concept to overcome these shortcomings is the cryopreservation of encapsulated allogenic islets. Recently, we reported a gentle cryopreservation protocol for rat islets encapsulated in an alginate-based microcapsule system. Here, we report for the first time long-term transplantation data of these cryopreserved microencapsulated islets. We detected a stable graft function for more than 12 month (experiments still continuing after transplantation of 2500 cryopreserved microencapsulated CD rat islets in streptozotocin-diabetic Wistar rats. Moreover, the glucose clearance rate during an IPGTT was well preserved up to 56 weeks after transplantation. In addition, hyperglycemic blood glucose levels after removal of rat islet grafts 12 and 56 weeks after transplantation confirmed the efficacy of the encapsulated islets. Finally, the retrieved encapsulated rat islets responded well with a 7-fold increase of insulin secretion to a glucose stimulus (12 and 56 weeks. In conclusion, our study demonstrates for the first time that cryopreservation of encapsulated rat islets is possible without substantial losses on graft function for a very long time.

  20. Chronic pancreatitis

    Science.gov (United States)

    Chronic pancreatitis - chronic; Pancreatitis - chronic - discharge; Pancreatic insufficiency - chronic; Acute pancreatitis - chronic ... abuse over many years. Repeated episodes of acute pancreatitis can lead to chronic pancreatitis. Genetics may be ...

  1. Nucleotide sequencing, cloning, and expression of Capra hircus Heme Oxygenase-1 in caprine islets to promote insulin secretion in vitro.

    Science.gov (United States)

    Vakhshiteh, Faezeh; Allaudin, Zeenathul Nazariah; Lila, Mohd Azmi B Mohd; Abbasiliasi, Sahar; Ajdari, Zahra

    2015-01-01

    Transplantation of islets of Langerhans that have been isolated from whole pancreas is an attractive alternative for the reversal of Type 1 diabetes. However, in vitro culture of isolated pancreatic islets has been reported to cause a decrease in glucose response over time. Hence, the improvement in islet culture conditions is an important goal in islet transplantation. Heme Oxygenase-1 (HO-1) is a stress protein that has been described as an inducible protein with the capacity of preventing apoptosis and cytoprotection via radical scavenging. Therefore, this study was aimed to assess the influence of endogenous HO-1 gene transfer on insulin secretion of caprine islets. The full-length cDNA sequence of Capra hircus HO-1 was determined using specific designed primers and rapid amplification of cDNA ends of pancreatic tissue. The HO-1 cDNA was then cloned into the prokaryotic expression vectors and transfected into caprine islets using lipid carriers. Efficiency of lipid carriers to transfect caprine islets was determined by flow cytometry. Insulin secretion assay was carried out by ovine insulin ELISA. The finding demonstrated that endogenous HO-1 gene transfer could improve caprine islet function in in vitro culture. Consequently, strategies using HO-1 gene transfer to islets might lead to better outcome in islet transplantation.

  2. Small intestinal submucosa improves islet survival and function during in vitro culture

    Institute of Scientific and Technical Information of China (English)

    Xiao-Hui Tian; Wu-Jun Xue; Xiao-Ming Ding; Xin-Lu Pang; Yan Teng; Pu-Xun Tian; Xin-Shun Feng

    2005-01-01

    AIM: To evaluate the recovery and function of isolated rat pancreatic islets during in vitro culture with small intestinal submucosa (SIS).METHODS: Pancreatic islets were isolated from Wistar rats by standard surgical procurement followed by intraductal collagenase distension, mechanical dissociation and Euroficoll purification. Purified islets were cultured in plates coated with multilayer SIS (SIS-treated group) or without multilayer SIS (standard cultured group) for 7 and 14 d in standard islet culture media of RPMI 1640. After isolation and culture, islets from both experimental groups were stained with dithizone and counted. Recovery of islets was determined by the ratio of counts after the culture to the yield of islets immediately following islet isolation. Viability of islets after the culture was assessed by the glucose challenge test with low (2.7 mmol/L) and high glucose (16.7 mmol/L)solution supplemented with 50 mmol/L 3-isobutyl-1-methylxanthine (IBMX) solution. Apoptosis of islet cells after the culture was measured by relative quantification of histone-complexed DNA fragments using ELISA.RESULTS: After 7 or 14 d of in vitro tissue culture, the recovery of islets in SIS-treated group was significantly higher than that cultured in plates without SIS coating. The recovery of islets in SIS-treated group was about twice more than that of in the control group. In SIS-treated group, there was no significant difference in the recovery of islets between short- and long-term periods of culture (95.8±1.0% vs 90.8±1.5%, P>0.05). When incubated with high glucose (16.7 mmol/L) solution,insulin secretion in SIS-treated group showed a higher increase than that in control group after 14 d of culture (20.7±1.1 mU/L vs11.8±1.1 mU/L, P0.05).Much less apoptosis of islet cells occurred in SIS-treated group than in control group after the culture.CONCLUSION: Co-culture of isolated rat islets with native sheet-like SIS might build an extracellular matrix for islets and

  3. Pathologic pancreatic endocrine cell hyperplasia

    Institute of Scientific and Technical Information of China (English)

    Debra Ouyang; Deepti Dhall; Run Yu

    2011-01-01

    Pathologic hyperplasia of various pancreatic endocrine cells is rare but has been long known. β cell hyperplasia contributes to persistent hyperinsulinemic hypoglycemia of infancy, which is commonly caused by mutations in the islet ATP-sensitive potassium channel, and to noninsulinoma pancreatogenous hypoglycemia in adults,which may or may not be associated with bariatric surgery.α cell hyperplasia may cause glucagonoma syndrome or induce pancreatic neuroendocrine tumors. An inactivating mutation of the glucagon receptor causes α cell hyperplasia and asymptomatic hyperglucagonemia.Pancreatic polypeptide cell hyperplasia has been described without a clearly-characterized clinical syndrome and hyperplasia of other endocrine cells inside the pancreas has not been reported to our knowledge.Based on morphological evidence, the main pathogenetic mechanism for pancreatic endocrine cell hyperplasia is increased endocrine cell neogenesis from exocrine ductal epithelium. Pancreatic endocrine cell hyperplasia should be considered in the diagnosis and management of hypoglycemia, elevated islet hormone levels,and pancreatic neuroendocrine tumors. Further studies of pathologic pancreatic endocrine cell hyperplasia will likely yield insights into the pathogenesis and treatment of diabetes and pancreatic neuroendocrine tumors.

  4. Protection of human islets from induction of apoptosis and improved islet function with HO-1 gene transduction

    Institute of Scientific and Technical Information of China (English)

    LI Yong-xiang; LI Ge; DONG Wei-ping; LU Da-ru; TAN Jian-ming

    2006-01-01

    Background Islet transplantation represents an ideal therapeutic approach for treatment of type 1 diabetes but islet function and regeneration may be influenced by necrosis or apoptosis induced by oxidative stress and other insults. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in the catabolism of heme into biliverdin,releasing free iron and carbon monoxide. It has also been reported to be an antioxidant enzyme which can improve the function of grafted islets by cytoprotection via free radical scavenging and apoptosis prevention. In the present study, we investigated whether transduction of HO-1 genes into human islets with an adenovirus vector has cytoprotective action on islets cultured in vitro and discuss this method of gene therapy for clinical islet transplantation.Methods Cadaveric pancreatic islets were isolated and purified in vitro. Transduction efficiency of islets was determined by infecting islets with adenovirus vector containing the enhanced green fluorescent protein gene (Ad-EGFP) at multiplicities of infection (MOI) of 2, 5, 10, or 20. Newly isolated islets were divided into three groups: EGFP group, islets transduced with Ad-EGFP using MOI=20; HO-1 group, transduced with adenovirus vectors containing the human HO-1 gene using MOI=20; and control group, mock transduced islets. Insulin release after glucose stimulation of the cell lines was determined by a radioimmunoassay kit and the stimulation index was calculated. Flow cytometry was used to detect apoptotic cells in the HO-1 group and in the control group after induction by recombinant human tumor necrosis factor-α (rTNFα) and cycloheximide (CHX) for 48 hours.Results Adenovirus vectors have a high efficiency of gene transduction into adult islet cells. Transduction of islets with the Ad-EGFP was most successful at MOI 20, at which MOI fluorescence was very intense on day 7 after transduction and EGFP was expressed in cultured islet cells for more than four weeks in vitro. The insulin

  5. 孕期糖代谢状况对早产儿早期胰岛功能的影响%Maternal glucose-insulin metabolism on early pancreatic islet function in premature infant

    Institute of Scientific and Technical Information of China (English)

    齐继; 刘戈力; 张平平; 初玉芹; 张金艳; 王玉亮

    2013-01-01

      目的分析母亲孕期糖代谢状况对其早产儿早期胰岛功能的影响,并探讨监测早产儿早期胰岛功能的敏感指标。方法将2012年3月至12月入住新生儿重症监护病房的82例早产儿分为2组,母亲孕期糖代谢异常组(35例)和母亲孕期糖代谢正常组(47例),分别检测早产儿生后1 h和7 d的空腹血糖(FPG)、胰岛素(FINS)、C-肽和胰岛素原,并比较早产儿胰岛β细胞功能的相关指数。结果两组早产儿母亲的孕前和产前体质指数(BMI)、早产儿出生时体质量和头围的差异均有统计学意义(P0.05)。两组早产儿出生时胰岛素原与生后7 d的C-肽、胰岛素原的差异有统计学意义(P0.05)。结论母亲孕期糖代谢异常并不影响早产儿早期胰岛功能,但早产儿早期胰岛素原的分泌已受影响。%Objectives To analyze the impact of glucose-insulin metabolism during pregnancy onβ-cell function in premature infant, and to explore biomarkers for monitoringβ-cell function in preterm infant. Methods Eighty-two premature infants admitted to NICU from March to December 2012 were divided into 2 groups, a group with abnormal maternal glucose metabolism during pregnancy (35 cases) and another group with normal maternal glucose metabolism during pregnancy group (47 cases). Fasting blood glucose, insulin, C-peptide and proinsulin at 1 hour after birth and 7 days postpartum were measured respectively, and relevant indices ofβ-cell function were compared in premature infants. Results Maternal pre-pregnancy and prenatal body mass index, weight and head circumference of preterm infants at birth were signiifcantly different between two groups (P0.05). The differences in levels of proinsulin at birth, C-peptide and proinsulin at postnatal day 7 were signiifcantly different between the two groups (P0.05). Conclusions Abnormal maternal glucose metabolism in pregnancy has no effect on early pancreatic islet

  6. 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....

  7. 体外诱导胰腺干细胞向胰岛样细胞团的分化%In vitro induced differentiation of pancreatic stem cells into islet-like cell clusters

    Institute of Scientific and Technical Information of China (English)

    岑妍慧; 谢小薰; 陈维平; 何国珍; 黄波; 郭文文; 肖燕子

    2012-01-01

    BACKGROUND: Because of lacking of islet sources, the islet cells transplantation for the treatment of diabetes can not meet the clinical demand, so the differentiation of pancreas stem cells into islets in vitro has become a focus of the research. OBJECTIVE: To in vitro induce the mice pancreas stem cells into the islet-like cell clusters and to perform the relate measurement; to investigate the techniques and methods to differentiate the pancreas stem cells into the islets as well as the detection method. METHODS: The mice pancreas stem cells were obtained in vi tro, and then the joint inducer was used to induce the pancreas stem cells to differentiate into islets. The islet- like cell clusters were preformed with morphological observation, dithizone dyeing, RT-PCR and Western blot detection. RESULTS AND CONCLUSION: Through the observation of cell morphology and cell growth characteristics and immunocytochemistry staining, we obtained mice pancreas stem cells in vitro. The joint inducer was used to induce the mice pancreas stem cells to differentiate into islet-like cells, the cells were spherical with a more slender pedicle connected with the bottom, and the cells was stained iron red by dithizone dyeing. The results of RT-PCR and Western blot determined the expression of insulin mRNA and insulin protein of islet-like cells respectively. It confirms that the mice pancreas stem cells can be induced in vitro to differentiate into beta containing islet- like cell clusters.%背景:目前由于胰岛来源匮乏,使得胰岛细胞移植治疗糖尿病无法满足临床需求,故体外将胰腺干细胞诱导分化为胰岛成为研究焦点.目的:于体外将小鼠胰腺干细胞诱导成胰岛样细胞团并对其进行相关检测,探寻一种胰腺干细胞体外诱导分化成胰岛及鉴定的技术和方法.方法:体外获得纯化的小鼠胰腺干细胞,采用联合诱导剂对其进行成胰岛方向的诱导分化,并对诱导

  8. Metabolic effects of successful intraportal islet transplantation in insulin-dependent diabetes mellitus.

    OpenAIRE

    Luzi, L; Hering, B.J.; Socci, C; Raptis, G.; Battezzati, A; Terruzzi, I; Falqui, L; Brandhorst, H; Brandhorst, D; Regalia, E; Brambilla, E.; Secchi, A.; Perseghin, G; Maffi, P; Bianchi, E.

    1996-01-01

    The intraportal injection of human pancreatic islets has been indicated as a possible alternative to the pancreas transplant in insulin-dependent diabetic patients. Aim of the present work was to study the effect of intraportal injection of purified human islets on: (a) the basal hepatic glucose production; (b) the whole body glucose homeostasis and insulin action; and (c) the regulation of insulin secretion in insulin-dependent diabetes mellitus patients bearing a kidney transplant. 15 recip...

  9. 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.

  10. 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.

  11. Frequency of pancreatic amyloid deposition in cats from south-eastern Queensland.

    Science.gov (United States)

    Lutz, T A; Ainscow, J; Rand, J S

    1994-08-01

    Stereological procedures were used to estimate the amount of amyloid deposition in the pancreatic islets of 83 cats from random sources in south-eastern Queensland. Most had only minor deposits of less than 20% of islet volume (median 9%), but deposits equal to more than 50% of the islet volume were found in 10% of the cats. Amyloid deposition in pancreatic islets was correlated with the age of the cat. Although similar observations have been made previously in cats from the USA, the frequency of amyloid deposition was higher in this population of cats from south-eastern Queensland.

  12. 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.

  13. Ontogeny of neuro-insular complexes and islets innervation in the human pancreas.

    Directory of Open Access Journals (Sweden)

    Alexandra E. Proshchina

    2014-04-01

    Full Text Available The ontogeny of the neuro-insular complexes (NIC and the islets innervation in human pancreas has not been studied in detail. Our aim was to describe the developmental dynamics and distribution of the nervous system structures in the endocrine part of human pancreas. We used doublestaining with antibodies specific to pan-neural markers (neuron-specific enolase (NSE and S100 protein and to hormones of pancreatic endocrine cells. NSE and S100-positive nerves and ganglia were identified in the human fetal pancreas from gestation week (gw 10 onwards. Later the density of S100 and NSE-positive fibers increased. In adults this network was sparse. The islets innervation started to form from gw 14. NSE-containing endocrine cells were identified from gw 12 onwards. Additionally, S100-positive cells were detected both in the periphery and within some of the islets starting at gw 14. The analysis of islets innervation has shown that the fetal pancreas contained neuro-insular complexes and the number of these complexes was reduced in adults. The highest density of neuro-insular complexes is detected during middle and late fetal periods, when the mosaic islets, typical for adults, form. The close integration between the developing pancreatic islets and the nervous system structures may play an important role not only in the hormone secretion, but also in the islets morphogenesis.

  14. Automated separation of merged Langerhans islets

    Science.gov (United States)

    Švihlík, Jan; Kybic, Jan; Habart, David

    2016-03-01

    This paper deals with separation of merged Langerhans islets in segmentations in order to evaluate correct histogram of islet diameters. A distribution of islet diameters is useful for determining the feasibility of islet transplantation in diabetes. First, the merged islets at training segmentations are manually separated by medical experts. Based on the single islets, the merged islets are identified and the SVM classifier is trained on both classes (merged/single islets). The testing segmentations were over-segmented using watershed transform and the most probable back merging of islets were found using trained SVM classifier. Finally, the optimized segmentation is compared with ground truth segmentation (correctly separated islets).

  15. Pleiotropic effects of GIP on islet function involve osteopontin

    DEFF Research Database (Denmark)

    Lyssenko, Valeriya; Eliasson, Lena; Kotova, Olga;

    2011-01-01

    The incretin hormone GIP (glucose-dependent insulinotropic polypeptide) promotes pancreatic β-cell function by potentiating insulin secretion and β-cell proliferation. Recently, a combined analysis of several genome-wide association studies (Meta-analysis of Glucose and Insulin-Related Traits...... Consortium [MAGIC]) showed association to postprandial insulin at the GIP receptor (GIPR) locus. Here we explored mechanisms that could explain the protective effects of GIP on islet function....

  16. A Wolf in Sheep's Clothing: A Non-Functioning Islet Cell Tumor of the Pancreas Masquerading as a Microcystic (Serous Cystic) Adenoma

    OpenAIRE

    Jowell PS; Baillie J; Tyler DS; Paulson EK; Xie HB; Byrne MF; Gerke H

    2004-01-01

    CONTEXT: The endosonographic appearance of a microcystic âhoneycombâ lesion of the pancreas usually indicates a serous cystic adenoma. CASE REPORT: We report a case of a non-functioning islet cell tumor that has the typical microcystic âhoneycombâ appearance of a serous cystic adenoma. The implications for endoscopic ultrasound diagnosis and management of cystic pancreatic lesions are discussed. CONCLUSION: Islet cell tumors are a rare differential diagnosis of microcystic pancreatic lesions....

  17. Early metabolic markers that anticipate loss of insulin independence in type 1 diabetic islet allograft recipients.

    Science.gov (United States)

    Hirsch, D; Odorico, J; Danobeitia, J S; Alejandro, R; Rickels, M R; Hanson, M; Radke, N; Baidal, D; Hullett, D; Naji, A; Ricordi, C; Kaufman, D; Fernandez, L

    2012-05-01

    The objective of this study was to identify predictors of insulin independence and to establish the best clinical tools to follow patients after pancreatic islet transplantation (PIT). Sequential metabolic responses to intravenous (I.V.) glucose (I.V. glucose tolerance test [IVGTT]), arginine and glucose-potentiated arginine (glucose-potentiated arginine-induced insulin secretion [GPAIS]) were obtained from 30 patients. We determined the correlation between transplanted islet mass and islet engraftment and tested the ability of each assay to predict return to exogenous insulin therapy. We found transplanted islet mass within an average of 16 709 islet equivalents per kg body weight (IEQ/kg BW; range between 6602 and 29 614 IEQ/kg BW) to be a poor predictor of insulin independence at 1 year, having a poor correlation between transplanted islet mass and islet engraftment. Acute insulin response to IVGTT (AIR(GLU) ) and GPAIS (AIR(max) ) were the most accurate methods to determine suboptimal islet mass engraftment. AIR(GLU) performed 3 months after transplant also proved to be a robust early metabolic marker to predict return to insulin therapy and its value was positively correlated with duration of insulin independence. In conclusion, AIR(GLU) is an early metabolic assay capable of anticipating loss of insulin independence at 1 year in T1D patients undergoing PIT and constitutes a valuable, simple and reliable method to follow patients after transplant.

  18. The efficacy of an immunoisolating membrane system for islet xenotransplantation in minipigs.

    Directory of Open Access Journals (Sweden)

    Tova Neufeld

    Full Text Available Developing a device that protects xenogeneic islets to allow treatment and potentially cure of diabetes in large mammals has been a major challenge in the past decade. Using xenogeneic islets for transplantation is required in light of donor shortage and the large number of diabetic patients that qualify for islet transplantation. Until now, however, host immunoreactivity against the xenogeneic graft has been a major drawback for the use of porcine islets. Our study demonstrates the applicability of a novel immunoprotective membrane that allows successful xenotransplantation of rat islets in diabetic minipigs without immunosuppressive therapy. Rat pancreatic islets were encapsulated in highly purified alginate and integrated into a plastic macrochamber covered by a poly-membrane for subcutaneous transplantation. Diabetic Sinclair pigs were transplanted and followed for up to 90 days. We demonstrated a persistent graft function and restoration of normoglycemia without the need for immunosuppressive therapy. This concept could potentially offer an attractive strategy for a more widespread islet replacement therapy that would restore endogenous insulin secretion in diabetic patients without the need for immunosuppressive drugs and may even open up an avenue for safe utilization of xenogeneic islet donors.

  19. 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.

  20. Islet-intrinsic effects of CFTR mutation.

    Science.gov (United States)

    Koivula, Fiona N Manderson; McClenaghan, Neville H; Harper, Alan G S; Kelly, Catriona

    2016-07-01

    Cystic fibrosis-related diabetes (CFRD) is the most significant extra-pulmonary comorbidity in cystic fibrosis (CF) patients, and accelerates lung decline. In addition to the traditional view that CFRD is a consequence of fibrotic destruction of the pancreas as a whole, emerging evidence may implicate a role for cystic fibrosis transmembrane-conductance regulator (CFTR) in the regulation of insulin secretion from the pancreatic islet. Impaired first-phase insulin responses and glucose homeostasis have also been reported in CF patients. CFTR expression in both human and mouse beta cells has been confirmed, and recent studies have shown differences in endocrine pancreatic morphology from birth in CF. Recent experimental evidence suggests that functional CFTR channels are required for insulin exocytosis and the regulation of membrane potential in the pancreatic beta cell, which may account for the impairments in insulin secretion observed in many CF patients. These novel insights suggest that the pathogenesis of CFRD is more complicated than originally thought, with implications for diabetes treatment and screening in the CF population. This review summarises recent emerging evidence in support of a primary role for endocrine pancreatic dysfunction in the development of CFRD. Summary • CF is an autosomal recessive disorder caused by mutations in the CFTR gene • The vast majority of morbidity and mortality in CF results from lung disease. However CFRD is the largest extra-pulmonary co-morbidity and rapidly accelerates lung decline • Recent experimental evidence shows that functional CFTR channels are required for normal patterns of first phase insulin secretion from the pancreatic beta cell • Current clinical recommendations suggest that insulin is more effective than oral glucose-lowering drugs for the treatment of CFRD. However, the emergence of CFTR corrector and potentiator drugs may offer a personalised approach to treating diabetes in the CF population

  1. Effects of methyl mercury on the activity and gene expression of mouse Langerhans islets and glucose metabolism.

    Science.gov (United States)

    Maqbool, Faheem; Bahadar, Haji; Niaz, Kamal; Baeeri, Maryam; Rahimifard, Mahban; Navaei-Nigjeh, Mona; Ghasemi-Niri, Seyedeh Farnaz; Abdollahi, Mohammad

    2016-07-01

    Mercury (Hg) is a well-known heavy metal and causes various toxic effects. It is abundantly present in fish in the form of methyl mercury (MeHg). Also, various other forms of mercury can enter human body either from environment like inhalation or through dental amalgams. The present study was designed to assess MeHg induced toxicity in mouse plasma and pancreatic islets with respect to insulin secretion, oxidative balance, glucose tolerance, gene expression, caspases 3 and 9 activities. MeHg was dissolved in tap water and administered at doses 2.5, 5 and 10 mg/kg/day, for 4 weeks. In mice, MeHg significantly caused increase in plasma insulin as well as C-peptides. Glucose intolerance, insulin resistance and hyperglycemia are main consequences of our study that correlate with the gene expression changes of glucose homeostasis as well. MeHg caused increase lipid peroxidation in a dose-dependent manner in plasma as well as pancreatic islets. In addition, total thiol molecules and ferrous reducing antioxidant power in MeHg treated group was decreased in plasma as well as pancreatic islets. Caspases 3 and 9 activities of pancreatic islets were upregulated in MeHg exposed animals. Reactive oxygen species were extremely high in pancreatic islets of MeHg treated groups. MeHg disrupted gluconeogenesis/glycogenolysis pathways and insulin secretory functions of islets by targeting GDH, GLUT2 and GCK genes of pancreatic islets. In conclusion, the current study revealed that insulin pathways, oxidative balance and glucose metabolism encoded genetic makeup are susceptible to MeHg toxicity and the subsequent oxidative stress and alternations in gene expression could lead toward functional abnormalities in other organs. PMID:27178136

  2. β-Cell regeneration through the transdifferentiation of pancreatic cells: Pancreatic progenitor cells in the pancreas.

    Science.gov (United States)

    Kim, Hyo-Sup; Lee, Moon-Kyu

    2016-05-01

    Pancreatic progenitor cell research has been in the spotlight, as these cells have the potential to replace pancreatic β-cells for the treatment of type 1 and 2 diabetic patients with the absence or reduction of pancreatic β-cells. During the past few decades, the successful treatment of diabetes through transplantation of the whole pancreas or isolated islets has nearly been achieved. However, novel sources of pancreatic islets or insulin-producing cells are required to provide sufficient amounts of donor tissues. To overcome this limitation, the use of pancreatic progenitor cells is gaining more attention. In particular, pancreatic exocrine cells, such as duct epithelial cells and acinar cells, are attractive candidates for β-cell regeneration because of their differentiation potential and pancreatic lineage characteristics. It has been assumed that β-cell neogenesis from pancreatic progenitor cells could occur in pancreatic ducts in the postnatal stage. Several studies have shown that insulin-producing cells can arise in the duct tissue of the adult pancreas. Acinar cells also might have the potential to differentiate into insulin-producing cells. The present review summarizes recent progress in research on the transdifferentiation of pancreatic exocrine cells into insulin-producing cells, especially duct and acinar cells. PMID:27330712

  3. Corneal avascularity is due to soluble VEGF receptor-1

    OpenAIRE

    Ambati, Balamurali K.; Nozaki, Miho; Singh, Nirbhai; Takeda, Atsunobu; Jani, Pooja D.; Suthar, Tushar; Albuquerque, Romulo J. C.; Richter, Elizabeth; Sakurai, Eiji; Newcomb, Michael T.; Kleinman, Mark E.; Caldwell, Ruth B.; Lin, Qing; OGURA, Yuichiro; Orecchia, Angela

    2006-01-01

    Corneal avascularity—the absence of blood vessels in the cornea—is required for optical clarity and optimal vision, and has led to the cornea being widely used for validating pro- and anti-angiogenic therapeutic strategies for many disorders1-4. But the molecular underpinnings of the avascular phenotype have until now remained obscure5-10 and are all the more remarkable given the presence in the cornea of vascular endothelial growth factor (VEGF)-A, a potent stimulator of angiogenesis, and th...

  4. A Simple High Efficiency Intra-Islet Transduction Protocol Using Lentiviral Vectors.

    Science.gov (United States)

    Jimenez-Moreno, Carmen Maria; Herrera-Gomez, Irene de Gracia; Lopez-Noriega, Livia; Lorenzo, Petra Isabel; Cobo-Vuilleumier, Nadia; Fuente-Martin, Esther; Mellado-Gil, Jose Manuel; Parnaud, Geraldine; Bosco, Domenico; Gauthier, Benoit Raymond; Martin-Montalvo, Alejandro

    2015-01-01

    Successful normalization of blood glucose in patients transplanted with pancreatic islets isolated from cadaveric donors established the proof-of-concept that Type 1 Diabetes Mellitus is a curable disease. Nonetheless, major caveats to the widespread use of this cell therapy approach have been the shortage of islets combined with the low viability and functional rates subsequent to transplantation. Gene therapy targeted to enhance survival and performance prior to transplantation could offer a feasible approach to circumvent these issues and sustain a durable functional β-cell mass in vivo. However, efficient and safe delivery of nucleic acids to intact islet remains a challenging task. Here we describe a simple and easy-to-use lentiviral transduction protocol that allows the transduction of approximately 80 % of mouse and human islet cells while preserving islet architecture, metabolic function and glucose-dependent stimulation of insulin secretion. Our protocol will facilitate to fully determine the potential of gene expression modulation of therapeutically promising targets in entire pancreatic islets for xenotransplantation purposes. PMID:26122098

  5. Angiopoetin-2 Signals Do Not Mediate the Hypervascularization of Islets in Type 2 Diabetes

    Science.gov (United States)

    Shah, Payal; Lueschen, Navina; Ardestani, Amin; Oberholzer, Jose; Olerud, Johan; Carlsson, Per-Ola; Maedler, Kathrin

    2016-01-01

    Aims Changes in the islet vasculature have been implicated in the regulation of β-cell survival and function during the progression to type 2 diabetes (T2D). Failure of the β-cell to compensate for the increased insulin demand in obesity eventually leads to diabetes; as a result of the complex interplay of genetic and environmental factors (e.g. ongoing inflammation within the islets) and impaired vascular function. The Angiopoietin/Tie (Ang/Tie) angiogenic system maintains vasculature and is closely related to organ inflammation and angiogenesis. In this study we aimed to identify whether the vessel area within the islets changes in diabetes and whether such changes would be triggered by the Tie-antagonist Ang-2. Methods Immunohistochemical and qPCR analyses to follow islet vascularization and Ang/Tie levels were performed in human pancreatic autopsies and isolated human and mouse islets. The effect of Ang-2 was assessed in β-cell-specific Ang-2 overexpressing mice during high fat diet (HFD) feeding. Results Islet vessel area was increased in autopsy pancreases from patients with T2D. The vessel markers Tie-1, Tie-2 and CD31 were upregulated in mouse islets upon HFD feeding from 8 to 24 weeks. Ang-2 was transiently upregulated in mouse islets at 8 weeks of HFD and under glucolipotoxic conditions (22.2 mM glucose/ 0.5 mM palmitate) in vitro in human and mouse islets, in contrast to its downregulation by cytokines (IL-1β, IFN-ɣ and TNF-α). Ang-1 on the other hand was oppositely regulated, with a significant loss under glucolipotoxic condition, a trend to reduce in islets from patients with T2D and an upregulation by cytokines. Modulation of such changes in Ang-2 by its overexpression or the inhibition of its receptor Tie-2 impaired β-cell function at basal conditions but protected islets from cytokine induced apoptosis. In vivo, β-cell-specific Ang-2 overexpression in mice induced hypervascularization under normal diet but contrastingly led to

  6. Pig islets for islet xenotransplantation: current status and future perspectives

    Institute of Scientific and Technical Information of China (English)

    Hu Qinghua; Liu Zhongwei; Zhu Haitao

    2014-01-01

    Objective To review the current status and progress on pig islet xenotransplantation.Data sources Data used in this review were mainly from English literature of Pubmed database.The search terms were "pig islet" and "xenotransplantation".Study selection The original articles and critical reviews selected were relevant to this review's theme.Results Pigs are suggested to be an ideal candidate for obtaining available islet cells for transplantation.However,the potential clinical application of pig islet is still facing challenges including inadequate yield of high-quality functional islets and xenorejection of the transplants.The former can be overcome mainly by selection of a suitable pathogen-free source herd and the development of isolation and purification technology.While the feasibility of successful preclinical pig islet xenotranplantation provides insights in the possible mechanisms of xenogeneic immune recognition and rejection to overwhelm the latter.In addition,the achievement of long-term insulin independence in diabetic models by means of distinct islet products and novel immunotherapeutic strategies is promising.Conclusions Pig islet xenotransplantation is one of the prospective treatments to bridge the gap between the needs of transplantation in patients with diabetes and available islet cells.Nonetheless,further studies and efforts are needed to translate obtained findings into tangible applications.

  7. Protective and curative effects of Cocos nucifera inflorescence on alloxan-induced pancreatic cytotoxicity in rats

    Directory of Open Access Journals (Sweden)

    Raveendran S Renjith

    2012-01-01

    Conclusion: The results obtained in the study indicate the protective and curative effects of CnI on alloxan-induced pancreatic cytotoxicity, which is mediated through the regulation of carbohydrate metabolic enzyme activities and islets cell repair.

  8. Autoantibodies in chronic pancreatitis

    DEFF Research Database (Denmark)

    Rumessen, J J; Marner, B; Pedersen, N T;

    1985-01-01

    In 60 consecutive patients clinically suspected of having chronic pancreatitis the serum concentration of the immunoglobulins (IgA, IgG, IgM), the IgG- and IgA-type non-organ-specific autoantibodies against nuclear material (ANA), smooth and striated muscle, mitochondria, basal membrane, and reti......In 60 consecutive patients clinically suspected of having chronic pancreatitis the serum concentration of the immunoglobulins (IgA, IgG, IgM), the IgG- and IgA-type non-organ-specific autoantibodies against nuclear material (ANA), smooth and striated muscle, mitochondria, basal membrane......, and reticulin, and the IgG- and IgA-type pancreas-specific antibodies against islet cells, acinus cells, and ductal cells (DA) were estimated blindly. In 23 of the patients chronic pancreatitis was verified, whereas chronic pancreatitis was rejected in 37 patients (control group). IgG and IgA were found...... in significantly higher concentrations in the patients with chronic pancreatitis than in the control group but within the normal range. ANA and DA occurred very frequently in both groups but with no statistical difference. Other autoantibodies only occurred sporadically. The findings of this study do not support...

  9. Microcystic adenoma of the pancreas associated with non-functioning islet cell tumor: a case report

    International Nuclear Information System (INIS)

    Among cystic tumors arising in the pancreas, microcystic adenoma is relatively uncommon;it is usually benign, and is comprised of cysts that vary in size from microscopic to 2 cm in diameter. It has recently been reported to be associated with other pancreatic tumors with malignant potential; in particular, microcystic adenoma with coexistent islet cell tumor has been reported in von Hippel-Lindau disease. We report a case of microcystic adenoma of the pancreas associated with coexistent surgically-proven islet cell tumor. On spiral CT, the islet cell tumor was seen as a highly enhanced inhomogeneous solid mass in the pancreatic head, and microcystic adenoma as numerous small cysts throughout the pancreas.=20

  10. Avascular necrosis of the femoral head in HIV infected patients

    Directory of Open Access Journals (Sweden)

    Marcos Almeida Matos

    2007-02-01

    Full Text Available Avascular necrosis (AVN of the femoral head is an emerging complication in HIV infected patients. It has been suggested that the increased incidence of AVN in this population may be caused by an increased prevalence of predisposing factors for osteonecrosis, including protease inhibitors, hyperlipidemia, corticosteroid use, alcohol and intravenous drug abuse. The aim of this study was to assess the risk factors for avascular necrosis developing in the femoral head of HIV infected individuals. This study consisted of meta-analysis of the secondary data extracted from current literature. The selected articles allowed two study groups to be drawn up for comparison. Group 1 comprised 324 individuals infected by the HIV virus, who did not present femoral head AVN. Group 2 comprised 32 HIV positive patients, who presented femoral head AVN. The parameters used for analysis were as follows: age, gender, sexual preference, use of intravenous drugs, time of diagnosis, CD4+ cell count, use of antiretroviral agents and duration, serum cholesterol and serum triglycerides. The present study found a statistically significant association between hypertriglyceridemia, hypercholesterolemia, sexual preference and intravenous drug abuse. The authors concluded that femoral head osteonecrosis is associated with hyperlipidemia (hypercholesterolemia and hypertriglyceridemia and intravenous drug abuse. This study supports the hypothesis that protease inhibitors play a role in the development of osteonecrosis through a tendency to cause hyperlipidemia.

  11. Regulation of the JNK3 signaling pathway during islet isolation: JNK3 and c-fos as new markers of islet quality for transplantation.

    Directory of Open Access Journals (Sweden)

    Saida Abdelli

    Full Text Available Stress conditions generated throughout pancreatic islet processing initiate the activation of pro-inflammatory pathways and beta-cell destruction. Our goal is to identify relevant and preferably beta-specific markers to assess the activation of beta-cell stress and apoptotic mechanisms, and therefore the general quality of the islet preparation prior to transplantation. Protein expression and activation were analyzed by Western blotting and kinase assays. ATP measurements were performed by a luminescence-based assay. Oxygen consumption rate (OCR was measured based on standard protocols using fiber optic sensors. Total RNA was used for gene expression analyzes. Our results indicate that pancreas digestion initiates a potent stress response in the islets by activating two stress kinases, c-Jun N-terminal Kinase (JNK and p38. JNK1 protein levels remained unchanged between different islet preparations and following culture. In contrast, levels of JNK3 increased after islet culture, but varied markedly, with a subset of preparations bearing low JNK3 expression. The observed changes in JNK3 protein content strongly correlated with OCR measurements as determined by the Spearman's rank correlation coefficient rho [Formula: see text] in the matching islet samples, while inversely correlating with c-fos mRNA expression [Formula: see text]. In conclusion, pancreas digestion recruits JNK and p38 kinases that are known to participate to beta-cell apoptosis. Concomitantly, the islet isolation alters JNK3 and c-fos expression, both strongly correlating with OCR. Thus, a comparative analysis of JNK3 and c-fos expression before and after culture may provide for novel markers to assess islet quality prior to transplantation. JNK3 has the advantage over all other proposed markers to be islet-specific, and thus to provide for a marker independent of non-beta cell contamination.

  12. Circulating Levels of IL-1B+IL-6 Cause ER Stress and Dysfunction in Islets From Prediabetic Male Mice

    OpenAIRE

    O'Neill, Christina M.; Lu, Christine; Corbin, Kathryn L.; Sharma, Poonam R.; Dula, Stacey B.; Carter, Jeffrey D.; Ramadan, James W.; Xin, Wenjun; Lee, Jae K.; Nunemaker, Craig S.

    2013-01-01

    Elevated levels of circulating proinflammatory cytokines are associated with obesity and increased risk of type 2 diabetes, but the mechanism is unknown. We tested whether proinflammatory cytokines IL-1B+IL-6 at low picogram per milliliter concentrations (consistent with serum levels) could directly trigger pancreatic islet dysfunction. Overnight exposure to IL-1B+IL-6 in islets isolated from normal mice and humans disrupted glucose-stimulated intracellular calcium responses; cytokine-induced...

  13. SPECTRUM OF FUNCTIONING ISLET CELL TUMOR ON MULTISLICE COMPUTED TOMOGRAPHY: EXPERIENCE ON 70 PATIENTS

    Institute of Scientific and Technical Information of China (English)

    Hua-dan Xue; Zheng-yu Jin; Wei Liu; Hao Sun; Reto Merges; Xuan Wang; Xiao-na Zhang; Yun Wang; Wen-min Zhao; Jiu-hong Chen

    2008-01-01

    Objective To review experience in preoperative detection of islet cell tumors using multislice computed tomo-graphy (MSCT) and summarize various imaging features of functioning islet cell tumors on enhanced MSCT.Methods Seventy patients with clinical or pathological diagnosis of functioning pancreatic islet cell tumor between October 2003 and February 2007 were included in this retrospective study. Seventy-four enhanced MSCT scans in these patients were identified. All MSCT scans were interpreted by two experienced radiologists by consensus interpretation.Surgery and pathology reports were used to confirm the diagnosis, localization, and size of tumors.Results Totally, 73 functioning islet cell tumors including 65 benign insulinomas, 2 benign giucagnnomas, 3 ma-lignant insulinomas, and 3 malignant glucagonomas were pathologically diagnosed. Tumors in only two cases were not found by MSCT. In 67 benign lesions, 32 showed typical enhancement style, 21 showed prolonged enhancement in por-tal venous phase, 4 showed delayed enhancement, 4 had iso-dense enhancement with normal pancreatic parenchyma, 2 had no enhancement at all in arterial phase and portal venous phase, and 4 had inhomogeneous enhancement with necro-sis or cyst-formation. Patchy or spotty calcifications were found in 3 of the 67 tumors. In 6 malignant islet cell tumors,vessel invasion (2/6) and bowel invasion (1/6) were seen. Different enhancement patterns were shown. All hepatic metastases showed hyper-enhancement during their arterial phase.Conelusions Pancreatic islet cell tumor may display a wide spectrum of presentations in MSCT. Umors with unu-sual appearances often present as diagunstie challenges. Non-contrast and post-contrast multiphase scans are recommen-ded for the localization of functioning islet cell tumors.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

  16. Histomorphology of the bottlenose dolphin (Tursiops truncatus) pancreas and association of increasing islet β-cell size with chronic hypercholesterolemia.

    Science.gov (United States)

    Colegrove, Kathleen M; Venn-Watson, Stephanie

    2015-04-01

    Bottlenose dolphins (Tursiops truncatus) can develop metabolic states mimicking prediabetes, including hyperinsulinemia, hyperlipidemia, elevated glucose, and fatty liver disease. Little is known, however, about dolphin pancreatic histomorphology. Distribution and area of islets, α, β, and δ cells were evaluated in pancreatic tissue from 22 dolphins (mean age 25.7years, range 0-51). Associations of these measurements were evaluated by sex, age, percent high glucose and lipids during the last year of life, and presence or absence of fatty liver disease and islet cell vacuolation. The most common pancreatic lesions identified were exocrine pancreas fibrosis (63.6%) and mild islet cell vacuolation (47.4%); there was no evidence of insulitis or amyloid deposition, changes commonly associated with type 2 diabetes. Dolphin islet architecture appears to be most similar to the pig, where α and β cells are localized to the central or periphery of the islet, respectively, or are well dispersed throughout the islet. Unlike pigs, large islets (greater than 10,000μm(2)) were common in dolphins, similar to that found in humans. A positive linear association was identified between dolphin age and islet area average, supporting a compensatory response similar to other species. The strongest finding in this study was a positive linear association between islet size, specifically β-cells, and percent blood samples with high cholesterol (greater than 280mg/dl, R(2)=0.57). This study is the most comprehensive assessment of the dolphin pancreas to date and may help direct future studies, including associations between chronic hypercholesterolemia and β-cell size.

  17. Pancreatic Tuberculosis or Autoimmune Pancreatitis

    OpenAIRE

    Ayesha Salahuddin; Muhammad Wasif Saif

    2014-01-01

    Introduction. Isolated pancreatic and peripancreatic tuberculosis is a challenging diagnosis due to its rarity and variable presentation. Pancreatic tuberculosis can mimic pancreatic carcinoma. Similarly, autoimmune pancreatitis can appear as a focal lesion resembling pancreatic malignancy. Endoscopic ultrasound-guided fine needle aspiration provides an effective tool for differentiating between benign and malignant pancreatic lesions. The immune processes involved in immunoglobulin G4 relate...

  18. 六味地黄丸对自发性2型糖尿病模型小鼠胰岛素表达水平的影响%Effects of Liuweidihuang pill on insulin levels in sera and pancreatic islets from spontaneous mouse models of human type 2 diabetes administrated with different doses

    Institute of Scientific and Technical Information of China (English)

    吕璐; 郑源强; 张精彩; 李斯琦; 王晓东; 尹星; 徐佳; 韩新荣; 石艳春

    2016-01-01

    目的:探讨不同剂量六味地黄丸对自发性2型糖尿病模型小鼠血清和胰岛内胰岛素表达水平的影响。方法:将6~8周龄自发性2型糖尿病模型小鼠( KK-Ay小鼠)随机分3组(无药对照组、低剂量组、高剂量组), C57 BL/6 J小鼠作为遗传对照组,各组小鼠分别给予蒸馏水或六味地黄丸灌胃15周。每周测定空腹血糖、体质量、摄食量;给药15周后,ELISA法测定小鼠外周血血清胰岛素含量,免疫荧光法和免疫组织化学法检测胰岛中胰岛素表达水平,比较各组检测结果。结果:六味地黄丸给药后,KK-Ay小鼠空腹血糖降低,体质量和摄食量得到控制;给药组小鼠血清胰岛素含量和胰岛内胰岛素表达水平明显降低,且低剂量组的降低程度比高剂量组更明显。结论:六味地黄丸对自发性2型糖尿病模型小鼠高血糖、肥胖、胰岛素抵抗具有一定的治疗作用,且低剂量组降低血清和胰岛内胰岛素水平的效果优于高剂量组。%Objective:To investigate the effects of Liuweidihuang pill on the insulin levels in sera and pancreatic islets from spontaneous mouse models of human type 2 diabetes administrated with different doses .Methods:The 6-8 week-old KK-Ay mice were randomly divided into three groups including no drug control group ,low-dose group and high-dose group,in addition C57BL/6J mice were used as a genetic control group .All the animals were given with different dose Liuweidihuang pill solutions or sterile distilled water by intragastrical administration for fifteen weeks .The fasting blood glucose ,body mass and food consumption were measured weekly .The serum insulin levels were surveyed by ELISA .And the insulin levels in the pancreas islets were detected by immunofluorescence and immunohistochemistry .Results:Decreased fasting blood glucose ,controlled body mass and food consumption ,and lower levels of insulin in the sera and

  19. Pancreatic stem cells remain unresolved.

    Science.gov (United States)

    Jiang, Fang-Xu; Morahan, Grant

    2014-12-01

    Diabetes mellitus is caused by absolute (type 1) or relative (type 2) deficiency of insulin-secreting islet β cells. An ideal treatment of diabetes would, therefore, be to replace the lost or deficient β cells, by transplantation of donated islets or differentiated endocrine cells or by regeneration of endogenous islet cells. Due to their ability of unlimited proliferation and differentiation into all functional lineages in our body, including β cells, embryonic stem cells and induced pluripotent stem cells are ideally placed as cell sources for a diabetic transplantation therapy. Unfortunately, the inability to generate functional differentiated islet cells from pluripotent stem cells and the poor availability of donor islets have severely restricted the broad clinical use of the replacement therapy. Therefore, endogenous sources that can be directed to becoming insulin-secreting cells are actively sought after. In particular, any cell types in the developing or adult pancreas that may act as pancreatic stem cells (PSC) would provide an alternative renewable source for endogenous regeneration. In this review, we will summarize the latest progress and knowledge of such PSC, and discuss ways that facilitate the future development of this often controversial, but crucial research.

  20. Sustained NF-κB activation and inhibition in β-cells have minimal effects on function and islet transplant outcomes.

    Directory of Open Access Journals (Sweden)

    Aileen J F King

    Full Text Available The activation of the transcription factor NF-κB leads to changes in expression of many genes in pancreatic β-cells. However, the role of NF-κB activation in islet transplantation has not been fully elucidated. The aim of the present study was to investigate whether the state of NF-κB activation would influence the outcome of islet transplantation. Transgenic mice expressing a dominant active IKKβ (constitutively active or a non-degradable form of IκBα (constitutive inhibition under control of the rat insulin promoter were generated. Islets from these mice were transplanted into streptozotocin diabetic mice in suboptimal numbers. Further, the effects of salicylate (an inhibitor of NF-κB treatment of normal islets prior to transplantation, and the effects of salicylate administration to mice prior to and after islet implantation were evaluated. Transplantation outcomes were not affected using islets expressing a non-degradable form of IκBα when compared to wild type controls. However, the transplantation outcomes using islets isolated from mice expressing a constitutively active mutant of NF-κB were marginally worse, although no aberrations of islet function in vitro could be detected. Salicylate treatment of normal islets or mice had no effect on transplantation outcome. The current study draws attention to the complexities of NF-κB in pancreatic beta cells by suggesting that they can adapt with normal or near normal function to both chronic activation and inhibition of this important transcription factor.

  1. Regulation of Pancreatic Alpha Cell Function and Proliferation by Bone Morphogenetic Protein 4 (BMP4) in vitro

    DEFF Research Database (Denmark)

    Nielsen, Sofie Sylvest; Christensen, Gitte Lund; Holst, Jens Juul;

    2016-01-01

    Increased expression of Bone Morphogenetic Proteins (BMPs) in several tissues is associated with inflammation and Type II Diabetes Mellitus. BMP2 and BMP4 mRNA expression is increased in pancreatic islets from db/db mice and beta cell proliferation and function are inhibited by BMP4. The effect...... incubation with BMP4 in mouse islets, but not in human islets. The percentage of proliferating alpha cells was reduced from 7.3 to 0.2 % in mouse islets incubated with BMP4. Alpha cell proliferation in human islets ranged from 0 to 11.8 %, and BMP4 was found to inhibit proliferation of alpha cells from all...

  2. 奥曲肽对糖尿病大鼠胰岛形态及α、β细胞数量的影响%Effects of octreotide on the pathological morphology of pancreatic islet and the numbers of α, β cells in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    陈炜; 崔世维; 王粹芳

    2013-01-01

    目的 探讨奥曲肽治疗糖尿病的可行性.方法 将32只糖尿病模型大鼠随机分为模型组、奥曲肽组、胰岛素组和联合组各8只,另取8只正常大鼠作为正常组.奥曲肽组、胰岛素组及联合组分别皮下注射奥曲肽、甘精胰岛素及奥曲肽+甘精胰岛素治疗;模型组及正常组皮下注射等量生理盐水.干预4周后处死大鼠,取胰腺组织HE染色观察胰腺内胰岛数量与大体形态,采用免疫组化的方法观察单个胰岛中主要内分泌细胞(α、β细胞)数量以及分布.结果 与模型组比较,奥曲肽组、胰岛素组和联合组胰腺中胰岛数量较多,形态较规则,边缘较整齐,尤以奥曲肽组和联合组明显;但四组均明显少于正常组.单个胰岛中β细胞数量正常组>联合组>奥曲肽组>胰岛素组>模型组,P均<0.05.奥曲肽组、胰岛素组和联合组单个胰岛α细胞数量均明显高于模型组,P均<0.05;但均少于正常组,P均<0.05.α、β细胞数量比值正常组与联合组比较、联合组与奥曲肽组组比较,模型组与胰岛素组比较,P均>0.05,其余各组间比较P均<0.05.结论 奥曲肽可以提高单个胰岛内α、β细胞数量,降低仅、β细胞数量比值,减轻STZ导致的糖尿病大鼠胰岛的病理损害.%Objective To explore the feasibility of octreotide in treating diabetes.Methods A total of 32 model rats were randomly divided into four groups,8 rats each:model group,octreotide group,insulin group and combination group.Another 8 normal rats were taken as the normal group.The octreotide group,insulin group and combination group received subcutaneous injections of octreotide,insulin glargine,and octreotide and insulin glargine separately.The model group and normal group received an injection of same account of saline.The rats were executed after intervention for 4 weeks.The pancreatic tissues were taken out and HE stained,then the quantities and general forms of islets

  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. Diabetes imaging-quantitative assessment of islets of Langerhans distribution in murine pancreas using extended-focus optical coherence microscopy

    OpenAIRE

    Berclaz, Corinne; Goulley, Joan; Villiger, Martin; Pache, Christophe; Bouwens, Arno; Martin-Williams, Erica; Van De Ville, Dimitri; Davison, Anthony C.; Grapin-Botton, Anne; Lasser, Theo

    2012-01-01

    Diabetes is characterized by hyperglycemia that can result from the loss of pancreatic insulin secreting β-cells in the islets of Langerhans. We analyzed ex vivo the entire gastric and duodenal lobes of a murine pancreas using extended-focus Optical Coherence Microscopy (xfOCM). To identify and quantify the islets of Langerhans observed in xfOCM tomograms we implemented an active contour algorithm based on the level set method. We show that xfOCM reveals a three-dimensional islet distribution...

  5. Diabetes imaging — quantitative assessment of islets of Langerhans distribution in murine pancreas using extended-focus optical coherence microscopy

    OpenAIRE

    Berclaz, Corinne; Goulley, Joan; Villiger, Martin; Bouwens, Arno; Martin-Williams, Erica; Van De Ville, Dimitri; Davison, Anthony C.; Grapin-Botton, Anne; Lasser, Theo

    2012-01-01

    Diabetes is characterized by hyperglycemia that can result from the loss of pancreatic insulin secreting β-cells in the islets of Langerhans. We analyzed ex vivo the entire gastric and duodenal lobes of a murine pancreas using extended-focus Optical Coherence Microscopy (xfOCM). To identify and quantify the islets of Langerhans observed in xfOCM tomograms we implemented an active contour algorithm based on the level set method. We show that xfOCM reveals a three-dimensional islet distribution...

  6. Stress-induced adaptive islet cell identity changes.

    Science.gov (United States)

    Cigliola, V; Thorel, F; Chera, S; Herrera, P L

    2016-09-01

    The different forms of diabetes mellitus differ in their pathogenesis but, ultimately, they are all characterized by progressive islet β-cell loss. Restoring the β-cell mass is therefore a major goal for future therapeutic approaches. The number of β-cells found at birth is determined by proliferation and differentiation of pancreatic progenitor cells, and it has been considered to remain mostly unchanged throughout adult life. Recent studies in mice have revealed an unexpected plasticity in islet endocrine cells in response to stress; under certain conditions, islet non-β-cells have the potential to reprogram into insulin producers, thus contributing to restore the β-cell mass. Here, we discuss the latest findings on pancreas and islet cell plasticity upon physiological, pathological and experimental conditions of stress. Understanding the mechanisms involved in cell reprogramming in these models will allow the development of new strategies for the treatment of diabetes, by exploiting the intrinsic regeneration capacity of the pancreas. PMID:27615136

  7. Nitric oxide-induced expression of C-reactive protein in islet cells as a very early marker for islet stress in the rat pancreas.

    Science.gov (United States)

    Fehsel, K; Plewe, D; Kolb-Bachofen, V

    1997-06-01

    In searches for marker molecules specifically expressed in nitric oxide-treated islet cells as a means to recognize early events in islet destruction, we now establish the presence of neo-C-reactive protein (neoCRP) in rat islet cells as early as 2 hr after treatment. We detected this altered molecular form of the acute-phase-reactant C-reactive protein (CRP) using immunocytochemistry with an anti-neoCRP-specific monoclonal antibody as well as reverse transcription-polymerase chain reaction with CRP-specific primers and in situ hybridization to demonstrate the presence of CRP-specific mRNA. After induction of a generalized inflammatory reaction in rats with heat-inactivated Corynebacterium parvum in vivo, neoCRP expression in islets is also found and within the pancreas restricted to pancreatic islet cells only. Our findings suggest an early heat-shock-like expression of this molecule in response to local nitrite oxide production or to exogeneously added nitric oxide in islet cells. PMID:9704587

  8. Somatostatin receptor expression and biological functions in endocrine pancreatic cells: review based on a doctoral thesis.

    Science.gov (United States)

    Ludvigsen, Eva

    2007-01-01

    Type 1 diabetes is resulting from the selective destruction of insulin-producing betacells within the pancreatic islets. Somatostatin acts as an inhibitor of hormone secretion through specific receptors (sst1-5). All ssts were expressed in normal rat and mouse pancreatic islets, although the expression intensity and the co-expression pattern varied between ssts as well as between species. This may reflect a difference in response to somatostatin in islet cells of the two species. The Non-Obese Diabetic (NOD) mouse model is an experimental model of type 1 diabetes, with insulitis accompanied by spontaneous hyperglycaemia. Pancreatic specimens from NOD mice at different age and stage of disease were stained for ssts. The islet cells of diabetic NOD mice showed increased islet expression of sst2-5 compared to normoglycemic NOD mice. The increase in sst2-5 expression in the islets cells may suggest either a contributing factor in the process leading to diabetes, or a defense response against ongoing beta-cell destruction. Somatostatin analogues were tested on a human endocrine pancreatic tumour cell line and cultured pancreatic islets. Somatostatin analogues had an effect on cAMP accumulation, chromogranin A secretion and MAP kinase activity in the cell line. Treatment of rat pancreatic islets with somatostatin analogues with selective receptor affinity was not sufficient to induce an inhibition of insulin and glucagon secretion. However, a combination of selective analogues or non-selective analogues via costimulation of receptors can cause inhibition of hormone production. For insulin and glucagon, combinations of sst2 + sst5 and sst1 + sst2, respectively, showed a biological effect. In summary, knowledge of islet cell ssts expression and the effect of somatostatin analogues with high affinity to ssts may be valuable in the future attempts to influence beta-cell function in type 1 diabetes mellitus, since down-regulation of beta-cell function may promote survival of

  9. Fractal Dimension and Universality in Avascular Tumor Growth

    CERN Document Server

    Ribeiro, Fabiano L; Mata, Angélica S

    2016-01-01

    The comprehension of tumor growth is a intriguing subject for scientists. New researches has been constantly required to better understand the complexity of this phenomenon. In this paper, we pursue a physical description that account for some experimental facts involving avascular tumor growth. We have proposed an explanation of some phenomenological (macroscopic) aspects of tumor, as the spatial form and the way it growths, from a individual-level (microscopic) formulation. The model proposed here is based on a simple principle: competitive interaction between the cells dependent on their mutual distances. As a result, we reproduce many empirical evidences observed in real tumors, as exponential growth in their early stages followed by a power law growth. The model also reproduces the fractal space distribution of tumor cells and the universal behavior presented in animals and tumor growth, conform reported by West, Guiot {\\it et. al.}\\cite{West2001,Guiot2003}. The results suggest that the universal similar...

  10. Human islets contain four distinct subtypes of β cells.

    Science.gov (United States)

    Dorrell, Craig; Schug, Jonathan; Canaday, Pamela S; Russ, Holger A; Tarlow, Branden D; Grompe, Maria T; Horton, Tamara; Hebrok, Matthias; Streeter, Philip R; Kaestner, Klaus H; Grompe, Markus

    2016-01-01

    Human pancreatic islets of Langerhans contain five distinct endocrine cell types, each producing a characteristic hormone. The dysfunction or loss of the insulin-producing β cells causes diabetes mellitus, a disease that harms millions. Until now, β cells were generally regarded as a single, homogenous cell population. Here we identify four antigenically distinct subtypes of human β cells, which we refer to as β1-4, and which are distinguished by differential expression of ST8SIA1 and CD9. These subpopulations are always present in normal adult islets and have diverse gene expression profiles and distinct basal and glucose-stimulated insulin secretion. Importantly, the β cell subtype distribution is profoundly altered in type 2 diabetes. These data suggest that this antigenically defined β cell heterogeneity is functionally and likely medically relevant. PMID:27399229

  11. Insulin resistance alters islet morphology in nondiabetic humans

    DEFF Research Database (Denmark)

    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...

  12. Combination strategy of multi-layered surface camouflage using hyperbranched polyethylene glycol and immunosuppressive drugs for the prevention of immune reactions against transplanted porcine islets.

    Science.gov (United States)

    Haque, Muhammad R; Jeong, Jee-Heon; Byun, Youngro

    2016-04-01

    This study suggests a novel method of stabilizing fragile porcine islets to prevent the dissociation after isolation and reducing immune cell invasion in a combination therapy of 'surface camouflaging' and immunosuppressive drugs (FK506, Rapamycin, MR-1, anti-CD19 mAb, and Clodrosome(®)) to effectively alleviate overall immune reactions against xenotransplanted porcine islets. The surface camouflage of pancreatic islets using biocompatible materials improved stabilization of pancreatic islet and prevented the infiltration of immune cells. Firstly, the surface of porcine islets was camouflaged by SH-6-arm-PEG-lipid and gelatin-catechol (artificial extracellular matrix) in order to stabilize the fragile isolated islets. Secondly, three different PEG layers (6-arm-PEG-SH, 6-arm-PEG-catechol, and linear PEG-SH) were chemically conjugated onto the surface of the stabilized porcine islets. Both artificial extracellular matrix (artificial ECM) and PEGylation effectively covered the surface of porcine islets without increasing the size of the whole islet. In addition, the viability and functionality of the islets were not affected by this multi-layer surface modification. The multi-layer modification significantly reduced the attachment of human serum albumin, fibronectin, and immunoglobulin G in comparison to the control collagen surface. The combination effect of multi-layer PEGylation and cocktailed immunosuppressive drugs on the survival time of the transplanted islets was assessed in a xenogeneic porcine-to-mouse model. The median survival time (MST) of 'artificial ECM + PEGylation' group was 4-fold increased compared to that of control group. In addition, the MST of 'artificial ECM + PEGylation + drug' group was 2.16-fold increased, compared to the 'control + drug' group. In conclusion, we proposed a novel porcine islet transplantation protocol using surface multi-layer modification and cocktailed immunosuppressive drugs, for stabilization and

  13. Dopamine modulates insulin release and is involved in the survival of rat pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    Maria Jose Garcia Barrado

    Full Text Available The local synthesis of dopamine and its effects on insulin release have been described in isolated islets. Thus, it may be accepted that dopamine exerts an auto-paracrine regulation of insulin secretion from pancreatic beta cells. The aim of the present study is to analyze whether dopamine is a regulator of the proliferation and apoptosis of rat pancreatic beta cells after glucose-stimulated insulin secretion. Glucose stimulated pancreatic islets obtained from male Wistar rats were cultured with 1 or 10 μM dopamine from 1 to 12 h. Insulin secretion was analyzed by RIA. The cellular proliferation rate of pancreatic islets and beta cells was studied with immunocytochemical double labelling for both insulin and PCNA (proliferating cell nuclear antigen, and active caspase-3 was detected to evaluate apoptosis. The secretion of insulin from isolated islets was significantly inhibited (p<0.01, by treatment with 1 and 10 μM dopamine, with no differences between either dose as early as 1 h after treatment. The percentage of insulin-positive cells in the islets decreased significantly (p<0.01 after 1 h of treatment up to 12 h. The proliferation rate of insulin-positive cells in the islets decreased significantly (p<0.01 following treatment with dopamine. Apoptosis in pancreatic islets and beta cells was increased by treatment with 1 and 10 μM dopamine along 12 h. In conclusion, these results suggest that dopamine could modulate the proliferation and apoptosis of pancreatic beta cells and that dopamine may be involved in the maintenance of pancreatic islets.

  14. Systematic screening of imaging biomarkers for the Islets of Langerhans, among clinically available positron emission tomography tracers

    International Nuclear Information System (INIS)

    Introduction: Functional imaging could be utilized for visualizing pancreatic islets of Langerhans. Therefore, we present a stepwise algorithm for screening of clinically available positron emission tomography (PET) tracers for their use in imaging of the neuroendocrine pancreas in the context of diabetes. Methods: A stepwise procedure was developed for screening potential islet imaging agents. Suitable PET-tracer candidates were identified by their molecular mechanism of targeting. Clinical abdominal examinations were retrospectively analyzed for pancreatic uptake and retention. The target protein localization in the pancreas was assessed in silico by –omics approaches and the in vitro by binding assays to human pancreatic tissue. Results: Six putative candidates were identified and screened by using the stepwise procedure. Among the tested PET tracers, only [11C]5-Hydroxy-tryptophan passed all steps. The remaining identified candidates were falsified as candidates and discarded following in silico and in vitro screening. Conclusions: Of the six clinically available PET tracers identified, [11C]5-HTP was found to be a promising candidate for beta cell imaging, based on intensity of in vivo pancreatic uptake in humans, and islet specificity as assessed on human pancreatic cell preparations. The flow scheme described herein constitutes a methodology for evaluating putative islet imaging biomarkers among clinically available PET tracers

  15. MedlinePlus: Islet Cell Transplantation

    Science.gov (United States)

    ... Human Islet Transplantation. Islet Cell Transplantation -- see more articles Topic Image MedlinePlus Email Updates Get Islet Cell Transplantation updates by email What's this? GO GO National Institutes of Health The primary NIH organization for research on Islet Cell Transplantation is the ...

  16. Antagonistic effect of TNF-α on leptin-mediated inhibition of insulin synthesis and secretion in INS-1E cells and rat pancreatic islets%肿瘤坏死因子-α拮抗瘦素抑制胰岛素合成及分泌作用的实验观察

    Institute of Scientific and Technical Information of China (English)

    张阳; 卢永辉; 缪洪明; 卢忠燕; 甘立霞

    2011-01-01

    目的 探讨在炎症情况下,瘦素(leptin)对胰岛β细胞胰岛素合成与葡萄糖刺激的胰岛素分泌(glucose-stimulated insulin secretion,GSIS)功能的影响.方法 在含5.5 mmol/L葡萄糖培养基中培养传代的大鼠胰腺癌细胞系(INS-1E)和大鼠原代分离的胰岛,经生理浓度leptin(0.5 nmol/L)或TNF-α (2 ng/ml)及高浓度leptin(10 nmol/L)与TNF-α (20 ng/ml)单独及联合处理48 h后,在基础葡萄糖(3.3 mmol/L)或高糖(16.7 mmol/L)中分别刺激1 h,放免法检测葡萄糖刺激的GSIS功能;用RT-PCR方法检测胰岛素原(proinsulin) mRNA 表达水平,同时细胞经超声破胞后检测胞内胰岛素含量.结果 高浓度leptin(10 nmol/L)或TNF-α(20 ng/ml)单独刺激组与对照组以及低浓度leptin或TNF-α组相比,均可显著性抑制INS-1E细胞和原代胰岛的GSIS功能(P<0.05),与之相应的是细胞内proinsulin mRNA水平以及胞内胰岛素含量亦显著降低(P<0.01);但TNF-α +leptin联合刺激组中,胰岛素原mRNA水平及胰岛素蛋白含量均较leptin单独刺激并未进一步降低,反而有显著升高(P<0.05),提示TNF-α具有拮抗leptin抑制胰岛素基因表达和分泌的作用.结论 TNF-α可以干扰leptin对胰岛β细胞胰岛素合成和分泌的抑制作用.提示肥胖者体内升高的TNF-α可能通过拮抗leptin对胰岛素分泌的抑制作用,在肥胖伴随的高胰岛素血症的发生及葡萄糖代谢紊乱中具有重要作用.%Objective To study the influence of leptin on pancreatic 13 cell insulin synthesis and glucose-stimulated insulin secretion (GSIS) in inflammation. Methods INS-1 E rat insulinoma cells and freshly isolated rat pancreatic islets cultured in glucose (5.5 mmol/L)-containing media were treated with leptin (0.5 nmoL/L or 10 nmol/L), TNF-α (2 ng/ml or 20 ng/ml), or their combination (leptin 10 nmoL/L and TNF-α 20 ng/ml ) for 48 h. Then, the cells and islets were balanced with low-concentration glucose (3.3 mmoL/L) for 1 h to test the base

  17. Insulin secretion and glucose uptake by isolated islets of the hamster

    International Nuclear Information System (INIS)

    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-14C (1.0 μC/ml), the amount of insulin secreted and the 14CO2 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-4.5-3H into total extractable insulin (insulin + proinsulin). Thus, insulin and proinsulin appear to inhibit insulin release, but not insulin synthesis. (orig.)

  18. Role and mechanism of rosiglitazone on the impairment of insulin secretion induced by free fatty acids on isolated rat islets

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Background Prolonged exposure of pancreatic β-cells to fatty acids increases basal insulin secretion but inhibits glucose-stimulated insulin secretion. Rosiglitazone is a new antidiabetic agent of the thiazolidinediones. However, the relationship between thiazolidinediones and insulin secretion is highly controversial. The aim of this study is to explore the effect and mechanism of rosiglitazone on insulin secretion of islets under chronic exposure to free fatty acids (FFA).Methods Pancreatic islets were isolated from the pancreata of male Sprague-Dawley rats by the collagenase digestion and by the dextran gradient centrifugation method. The purified islets were cultured in the presence or absence of rosiglitazone and palmitate for 48 hours. The insulin secretion was measured by radioimmunoassay. The mRNA level of peroxisome proliferator-activated receptor (, uncoupling protein 2 (UCP-2) and insulin were determined by real-time polymerase chain reaction (PCR). The cell cytotoxicity assay was measured by cell counting kit-8. Results Islets exposed to elevated palmitate for 48 hours showed an increased basal and a decreased glucose-stimulated insulin secretion (P<0.01). The mRNA level of UCP-2 was increased by 3.7 fold in the 0.5 mmol/L concentration of palmitate. When islets were cultured with palmitate (0.5 mmol/L) in the presence of rosiglitazone (1.0 μmol/L), both basal and glucose-stimulated insulin secretion reversed to a pattern of control islets (P<0.05, P<0.01). The addition of rosiglitazone in the culture medium decreased the mRNA level of UCP-2 by 2.2 fold, having a statistically significant difference (P<0.05) as compared with islets cultured with palmitate alone. The cell viability was not affected. Conclusion The protective effects of rosiglitazone on insulin secretion of isolated pancreatic islets under chronic exposure to palmitate might be mediated through the downregulation of UCP-2 expression.

  19. Pancreatic Cancer

    Science.gov (United States)

    ... hormones that help control blood sugar levels. Pancreatic cancer usually begins in the cells that produce the juices. Some risk factors for developing pancreatic cancer include Smoking Long-term diabetes Chronic pancreatitis Certain ...

  20. 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.

  1. Acute pancreatitis

    OpenAIRE

    Bo-Guang Fan; Åke Andrén-Sandberg

    2010-01-01

    Background : Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims : The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods : We reviewed the English-language literature (Medline) addressing pancreatitis. Results : Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingest...

  2. Acute pancreatitis

    OpenAIRE

    Bo-Guang Fan; Åke Andrén-Sandberg

    2010-01-01

    Background: Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims: The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods: We reviewed the English-language literature (Medline) addressing pancreatitis. Results: Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion....

  3. ADCY5 Couples Glucose to Insulin Secretion in Human Islets

    OpenAIRE

    Hodson, David J.; Mitchell, Ryan K.; Marselli, Lorella; Pullen, Timothy J.; Gimeno Brias, Silvia; Semplici, Francesca; Katy L Everett; Cooper, Dermot M.F; Bugliani, Marco; Marchetti, Piero; Lavallard, Vanessa; Bosco, Domenico; Piemonti, Lorenzo; Johnson, Paul R.; Hughes, Stephen J.

    2014-01-01

    Single nucleotide polymorphisms (SNPs) within the ADCY5 gene, encoding adenylate cyclase 5, are associated with elevated fasting glucose and increased type 2 diabetes (T2D) risk. Despite this, the mechanisms underlying the effects of these polymorphic variants at the level of pancreatic β-cells remain unclear. Here, we show firstly that ADCY5 mRNA expression in islets is lowered by the possession of risk alleles at rs11708067. Next, we demonstrate that ADCY5 is indispensable for coupling gluc...

  4. 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

    Full Text Available BACKGROUND: 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. PRINCIPAL FINDINGS: 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. CONCLUSIONS: 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.

  5. Acute Pancreatitis and Pregnancy

    Science.gov (United States)

    ... Acute Pancreatitis > Acute Pancreatitis and Pregnancy test Acute Pancreatitis and Pregnancy Timothy Gardner, MD Acute pancreatitis is ... of acute pancreatitis in pregnancy. Reasons for Acute Pancreatitis and Pregnancy While acute pancreatitis is responsible for ...

  6. Ex vivo Expansion of Human Adult Pancreatic Cells with Properties of Distributed Stem Cells by Suppression of Asymmetric Cell Kinetics

    OpenAIRE

    Paré, JF; Sherley, JL

    2013-01-01

    Transplantation therapy for type I diabetes (T1D) might be improved if pancreatic stem cells were readily available for investigation. Unlike macroscopic islets, pancreatic tissue stem cells could more easily access the retroperitoneal pancreatic environment and thereby might achieve more effective pancreatic regeneration. Unfortunately, whether the adult pancreas actually contains renewing stem cells continues as a controversial issue in diabetes research. We evaluated a new method developed...

  7. Biochemical characterization of two crotamine isoforms isolated by a single step RP-HPLC from Crotalus durissus terrificus (South American rattlesnake) venom and their action on insulin secretion by pancreatic islets.

    Science.gov (United States)

    Toyama, M H; Carneiro, E M; Marangoni, S; Barbosa, R L; Corso, G; Boschero, A C

    2000-03-01

    Crotamine, a neurotoxin present in the venom of the South American rattlesnake Crotalus durrisus terrificus exists as several polymorphic variants, as demonstrated by recombinant DNA technology (Smith and Schmidt, Toxicon 28 (1990) 575-585). We have isolated native crotamine by chromatography on Sephadex G75, and have purified two crotamine isoforms (F2 and F3) by a single step of RP-HPLC. Native crotamine and RP-HPLC fractions F2 and F3 produced skeletal muscle spasms and spastic paralysis in mice. At low glucose concentrations (2.8-5.6 mmol/l), none of the crotamines altered the insulin secretion by rat isolated islets. In the presence of 16.7 mmol glucose/l, F2 (5 microg/ml), but not F3, increased insulin secretion two-fold, whereas native crotamine (1.5, 5 and 16.5 microg/ml) potentiated the secretion dose-dependently. The increase in insulin secretion induced by F2 fraction (5 microg/ml) was similar to that obtained with 16.5 microg of native crotamine/ml. These results indicate that the mode of action of the F2 and F3 isoforms in beta-cells is different from that in muscle cells. This difference may be related to the binding affinity of each isoform for the Na(+) channels located in the beta-cell membrane. Crotamine isoforms may be valuable tools for studying the involvement of Na(+) channels in the mechanism of insulin secretion. PMID:10699490

  8. 胰腺上皮细胞可能成为胰岛β细胞再生的新来源%Pancreatic epithelium may be a new source of islet β cells regeneration

    Institute of Scientific and Technical Information of China (English)

    曹书义; 袁莉

    2015-01-01

    促进β细胞再生,维持功能性β细胞的数量,是治疗糖尿病的根本.胰腺上皮细胞包括β细胞、导管细胞、腺泡细胞及α细胞.研究表明,与多能干细胞相比,这些成体细胞具有更明显的优势,可能通过不同途径重新生成β细胞从而实现β细胞的再生.已分化的β细胞可以被诱导增殖或者退回至祖细胞状态重新分化为β细胞.而在胰腺受损、代谢应激、基因操作等条件下,其他胰腺上皮细胞可能直接转分化为β细胞或者成为内分泌兼性祖细胞再分化为β细胞.%Promoting β cells regeneration and increasing the number of functional β cells is crucial to treat diabetes.Pancreatic epithelial cells include β cell,duct cell acinar cell,and α cell.Compared with pluripotent stem cells,the adult cells have a clear advantage to realize the regeneration of β cells through different pathways.The differentiated β cells can be induced to proliferation or lost to dedifferentiation.Then the dedifferentiated cells may redifferentiate to β cells.Under specific conditions such as damaged pancreas,metabolic stress,genetic operation,other cells in pancreatic epithelium also exhibit the plasticity to go directly to β cells or become endocrine facultative progenitor cells to reprogramme into β cells.

  9. Avascular necrosis of the femoral head at 2 years after pertrochanteric fracture surgery: Case report

    Directory of Open Access Journals (Sweden)

    Bogdan Deleanu

    2016-02-01

    Conclusion: The avascular necrosis of the femoral head is a complication of pertrochanteric fractures that can not be foreseen or avoided. The optimal treatment in these cases is uncemented total hip arthroplasty.

  10. Effects of supraphysiologic concentration glucose on pancreatic duodenal homeobox-1 expression and insulin secretion in rats

    Institute of Scientific and Technical Information of China (English)

    XIAO Chang-qing; DENG Hong-ming; HUANG Yun

    2007-01-01

    @@ The islet transcription factor pancreatic duodenal homeobox-1 (PDX-1, also known as insulin promoter factor-1 or IPF-1) is an orphan homeodomain protein that plays an important role in the development, proliferation,differentiation and maturation of pancreatic cells.

  11. Immunosuppression for islet transplantation.

    Directory of Open Access Journals (Sweden)

    Noguchi,Hirofumi

    2006-04-01

    Full Text Available The development by the Edmonton group of a sirolimus-based, steroid-free, low-tacrolimus regimen is a significant breakthrough that allows the rate of insulin independence after islet transplantation to increase from 13% to 80% at 1 year ; however, the rate is reduced to 50% at 3 years, attributed to prolonged tacrolimus exposure. Recently, immunosuppression agents such as cyclosporine, mycophenolate mofetil, and the novel agent FTY 720 have been used instead of tacrolimus. Lymphocytedepleting antibodies such as anti-thymocyte globulin, alemtuzumab, and hOKT3gamma 1 (ala, ala have been launched, and a costimulatory blockade of anti-CD40 monoclonal antibodies and CTLA4-Ig will be attempted in the near future. Moreover, the potential of a novel immunosuppressing peptide could now be realized using new technology called the protein transduction system. In this review, we show some of the most recent contributions to the advancement of knowledge in this field.

  12. Magnetic resonance imaging of avascular necrosis of the femoral head

    International Nuclear Information System (INIS)

    To evaluate the diagnostic value and limitation of magnetic resonance imaging (MRI) in avascular necrosis of the femoral head (ANF), clinical stages and types were examined on MRI scans of 68 femoral heads of 46 ANF patients. Stage 1 patients fell into two groups: (1) stage 1-A group of real ANF in which abnormal findings were observed on both MRI and bone scanning and (2) stage 1-B group of asymptomatic ANF in which MRI detected abnormality that was missed by bone scanning. In these groups, MRI showed inhomogeneous, band, and spotty patterns. Stage 2 or 3 patients tended to have homogeneous or ring-pattern hypointensities on MRI. Histological examination showed that repair reaction at the marginal site of hypointensity was partly responsible for the occurrence of hypointensities. In Stage 4 patients, not only femoral head but also acetabular site was visible as homogeneous hypointensity, which was similar to that in osteoarthritis. Because repair areas, as well as necrotic areas, were frequently visualized as hypointensities in Stages 2 or more, MRI might overestimate necrotic areas. (N.K.)

  13. 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-phenylalanine...... nor L-serine methyl ester, stimulate insulin secretion. In the presence of L-glutamine, however, the effect of L-serine was additive, while the methyl esters of L-serine and L-phenylalanine as well as native L-phenylalanine, potentiated the glucose-stimulated release of insulin. Measurements of islet...... 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...

  14. 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 ...

  15. Loss of β-cell identity occurs in type 2 diabetes and is associated with islet amyloid deposits

    NARCIS (Netherlands)

    Spijker, H Siebe; Song, Heein; Ellenbroek, Johanne H; Roefs, Maaike M; Engelse, Marten A; Bos, Erik; Koster, Abraham J; Rabelink, Ton J; Hansen, Barbara C; Clark, Anne; Carlotti, Françoise; de Koning, Eelco J P

    2015-01-01

    Loss of pancreatic islet β-cell mass and β-cell dysfunction are central in the development of type 2 diabetes (T2DM). We recently showed that mature human insulin-containing β-cells can convert into glucagon-containing α-cells ex vivo. This loss of β-cell identity was characterized by the presence o

  16. Immunohistochemical localization of polypeptide hormones in pancreatic endocrine cells of a dipnoan fish, Protopterus aethiopicus.

    Science.gov (United States)

    Scheuermann, D W; Adriaensen, D; Timmermans, J P; De Groodt-Lasseel, M H

    1991-01-01

    Light microscopical immunohistochemistry was used to demonstrate the regulatory peptides present in the endocrine pancreas of Protopterus aethiopicus. The peptides studied included insulin, glucagon, pancreatic polypeptide and somatostatin. The results showed that the 4 regulatory peptides commonly detected in the mammalian endocrine pancreas were immunologically discernible in this dipnoan fish. Large amounts of insulin-immunoreactive cells, in the centre of the pancreatic islets, were surrounded by a small rim of glucagon-or pancreatic polypeptide-immunoreactive cells. In addition, adjacent sections stained with anti-glucagon and anti-pancreatic polypeptide revealed that these hormones could be found in the same cells. Somatostatin-positive cells were scattered throughout the islets. Their processes were seen to contact many different endocrine pancreatic cells, suggesting that the somatostatin-immunoreactive cells control the functions of other endocrine pancreatic cells. PMID:1687100

  17. Acute pancreatitis

    Directory of Open Access Journals (Sweden)

    Bo-Guang Fan

    2010-01-01

    Full Text Available Background : Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims : The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods : We reviewed the English-language literature (Medline addressing pancreatitis. Results : Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion. There are a number of important issues regarding clinical highlights in the classification, treatment and prognosis of acute pancreatitis, and treatment options for complications of acute pancreatitis including pancreatic pseudocysts. Conclusions : Multidisciplinary approach should be used for the management of the patient with acute pancreatitis.

  18. Acute pancreatitis

    Directory of Open Access Journals (Sweden)

    Bo-Guang Fan

    2010-05-01

    Full Text Available Background: Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims: The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods: We reviewed the English-language literature (Medline addressing pancreatitis. Results: Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion. There are a number of important issues regarding clinical highlights in the classification, treatment and prognosis of acute pancreatitis, and treatment options for complications of acute pancreatitis including pancreatic pseudocysts. Conclusions: Multidisciplinary approach should be used for the management of the patient with acute pancreatitis.

  19. 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

    Aging associates with impaired pancreatic islet function and increased type 2 diabetes (T2D) risk. Here we examine whether age-related epigenetic changes affect human islet function and if blood-based epigenetic biomarkers reflect these changes and associate with future T2D. We analyse DNA...... methylation genome-wide in islets from 87 non-diabetic donors, aged 26-74 years. Aging associates with increased DNA methylation of 241 sites. These sites cover loci previously associated with T2D, for example, KLF14. Blood-based epigenetic biomarkers reflect age-related methylation changes in 83 genes...... demonstrate that blood-based epigenetic biomarkers reflect age-related DNA methylation changes in human islets, and associate with insulin secretion in vivo and T2D....

  20. Pancreatic effects of GLP-1

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Albrechtsen, Nicolai Jacob Wewer; Holst, Jens Juul

    2014-01-01

    inhibits glucagon secretion in patients with type 1 diabetes mellitus. Besides these acute effects on the endocrine pancreas, GLP-1 also appears to have a positive effect on β-cell mass. In the following we will review GLP-1’s pancreatic effects with particular focus on its effects on pancreatic islets......-dependent manner. But perhaps equally importantly, GLP-1’s glucose lowering effects are attributable to a strong inhibition of glucagon secretion, and, thereby, a reduction of hepatic glucose output. The effects of GLP-1 on insulin secretion are mediated by binding of the hormone to the receptor (GLP-1r......) on the pancreatic β-cell, which increases intracellular cAMP levels and sets in motion a plethora of events that lead to secretion. In contrast, the inhibitory effect of GLP-1 on the α-cell may be indirect, involving paracrine intra-islet regulation by somatostatin and possibly also insulin, although GLP-1 also...

  1. Radioimmunodetection with 111In-labeled monoclonal antibody Nd2 in patients with pancreatic cancer

    International Nuclear Information System (INIS)

    This report summarizes results from an initial clinical evaluation of radioimmunodetection (RAID) in patients with pancreatic cancer using murine monoclonal antibody Nd2, directed against mucins from pancreatic cancer. Nd2 (2 mg) was labeled with 111In (2 mCi) and injected into 19 patients suspected of having pancreatic cancer. Planar scintigrams were taken 3 days post-infusion. As for final diagnoses after surgery, 14 cases were pancreatic cancer, and one case each was chronic pancreatitis, neurilemmoma, islet cell carcinoma, cholangioma, and apparent absence of suspected recurrent lesion of pancreatic cancer. Of 14 patients with pancreatic cancer, RAID was positive in 10 cases (71.4%). Cases other than pancreatic cancer were all negative, so the specificity was 100%. These results demonstrate that RAID using 111In-Nd2 can be useful in differentiating exocrine pancreatic cancer from benign conditions and other types of carcinomas in the pancreatoduodenal regions. (author)

  2. Biomechanical comparisons between a new avascular necrosis of femaral head stem based on Chinese patients with avascular necrosis and two other designs

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiang; CHENG Cheng-kung; WEI Hung-wen; DONG Xiang; CHEN Yi-ting; LAI Yu-shu; WANG Yan

    2013-01-01

    Background There is a relatively high failure rate of the femoral component in patients with avascuiar necrosis at the intermediate-term follow-up.Improving the geometrical fit of the femoral stem against the medullary canal may help to provide long-term survivorship of the hip replacement for patients with avascular necrosis.Methods We designed a specific stem,based on morphometric studies of proximal femoral canals in Chinese avascular necrosis patients and evaluated the stem by finite element analyses,comparing the novel stem with two commercially available and commonly used stems.Results The morphometric data from avascular necrosis patients showed specific geometric differences in the proximal femoral canal,including profile curves in both the sagittal and coronary planes than the patients with femoral neck fracture.The shorter stemmed prostheses (Fitmore(R) and our stem) performed better than the longer stemmed prosthesis (VerSys(R)).Conclusions This is the first study to investigate the femoral geometries of Chinese avascular necrosis patients.Our stem provides better stability and is theoretically beneficial to bone ingrowth,which may increase the long-term stability and fixation of the implant.

  3. 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.

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

    International Nuclear Information System (INIS)

    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 Ca2+ 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 Ca2+ 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

  5. Malignant nonfunctioning islet cell tumor of the pancreas with intrasplenic growth:a case report

    Institute of Scientific and Technical Information of China (English)

    Hong-Jiang Wang; Zuo-Wei Zhao; Hai-Feng Luo; Zhong-Yu Wang

    2006-01-01

    BACKGROUND: We reported a case of malignant nonfunction islet cell tumor (10.0 cm in diameter) of the pancreas, with malignant histological features and splenic inifltration. The case is rare, and few reports have been published. METHODS: A 46-year-old woman with a vague pain in the left upper quadrant for 3 months was found to have a tumor in the spleen. Ultrasonography and computed tomography demonstrated a well-deifned pancreatic tumor of 8.2×10.0 cm in size, her serum levels of pancreatic hormones were within normal limits. RESULTS: Splenectomy combined with pancreatectomy was performed for the tail of the pancreas. Resected specimens showed a malignant nonfunctioning islet cell tumor invading the spleen. CONCLUSIONS:The growth pattern of the tumor causes malignant features. Resection of the tumor should be performed by enucleation, pancreaticoduodenectomy or distal pancreatectomy.

  6. [Pancreatic Diseases].

    Science.gov (United States)

    Schöfl, Rainer

    2016-06-22

    The author presents his personal choice of practical relevant papers of pancreatic diseases from 2014 to 2015. Nutritional factors and hypertriglycidemia are discussed as causes of acute pancreatitis. Tools to avoid post-ERCP(endoscopic retrograde cholangiopancreatography) pancreatitis are described and the natural course of fluid collections and pseudocysts is demonstrated. The value of secretin-MRCP(magnetic resonance cholangiopancreatography) for diagnosis of chronic pancreatitis is illustrated. Data help to choose the minimally effective prednisolone dose in autoimmune pancreatitis. The increased prevalence of fractures in patients with chronic pancreatitis highlights the necessity of screening for bone density loss. The association of vitamin D intake with pancreatic cancer is described. The probability of cancer in IPNM is shown and innovative surgical concepts to reduce the loss of pancreatic function are presented. Finally neoadjuvant concepts for the treatment of pancreatic cancer are highlighted. PMID:27329710

  7. Connexins protect mouse pancreatic β cells against apoptosis.

    Science.gov (United States)

    Klee, Philippe; Allagnat, Florent; Pontes, Helena; Cederroth, Manon; Charollais, Anne; Caille, Dorothée; Britan, Aurore; Haefliger, Jacques-Antoine; Meda, Paolo

    2011-12-01

    Type 1 diabetes develops when most insulin-producing β cells of the pancreas are killed by an autoimmune attack. The in vivo conditions modulating the sensitivity and resistance of β cells to this attack remain largely obscure. Here, we show that connexin 36 (Cx36), a trans-membrane protein that forms gap junctions between β cells in the pancreatic islets, protects mouse β cells against both cytotoxic drugs and cytokines that prevail in the islet environment at the onset of type 1 diabetes. We documented that this protection was at least partially dependent on intercellular communication, which Cx36 and other types of connexin channels establish within pancreatic islets. We further found that proinflammatory cytokines decreased expression of Cx36 and that experimental reduction or augmentation of Cx36 levels increased or decreased β cell apoptosis, respectively. Thus, we conclude that Cx36 is central to β cell protection from toxic insults. PMID:22056383

  8. Pancreatic differentiation from pluripotent stem cells: Tweaking the system

    Institute of Scientific and Technical Information of China (English)

    Andrew M Holland; Andrew G Elefanty; Edouard G Stanley

    2009-01-01

    @@ Autoimmune destruction of insulin producing pancreatic β cells results in type 1 diabetes, a condition for which there is presently no cure. Clinical trials indicate that, in some instances, control of blood glucose can be restored by transplantation of cadaveric derived islets [1], raising hopes that such cell-based therapies may eventually form part of a curative treatment.

  9. Islet neogenesis: an apparent key component of long-term pancreas adaptation to increased insulin demand.

    Science.gov (United States)

    Del Zotto, H; Borelli, M I; Flores, L; García, M E; Gómez Dumm, C L; Chicco, A; Lombardo, Y B; Gagliardino, J J

    2004-11-01

    This study aimed to determine the relative importance of different functional and morphological pancreatic changes induced by the chronic administration of a sucrose-rich diet (SRD) to maintain normal glucose homeostasis. Male Wistar rats were fed either sucrose (SRD) or starch (CD) for 6 and 12 months. At both periods, serum glucose and triacylglycerol levels were significantly higher (Pcurve in SRD rats showed a shift to the left that was no longer observed at 12 months, when SRD islets decreased their response to 16 mM glucose. At 6 months, SRD rats showed a significant increase in beta-cell volume density (Vvi) and islet cell replication rate, together with a decrease in beta-cell apoptotic rate. Changes were not detected in the percentage of PDX-1- and islet neogenesis associated protein (INGAP)-positive cells. Conversely, at 12 months, there was a significant decrease in beta-cell Vvi and in the percentage of PDX-1-positive cells; the islet cell replication rate was not modified, and the number of apoptotic beta-cells increased significantly. No signs of increased neogenesis or INGAP-positive cells were recorded at any period in SRD rats. Our results show that SRD rats are unable to develop functional and morphological pancreatic reactive changes sufficient to maintain normal glucose and triacylglycerol levels for a long period. Such failure could be ascribed to their inability to increase the rate of neogenesis and of INGAP production. PMID:15531720

  10. Islet amyloid polypeptide inserts into phospholipid monolayers as monomer.

    Science.gov (United States)

    Engel, Maarten F M; Yigittop, HaciAli; Elgersma, Ronald C; Rijkers, Dirk T S; Liskamp, Rob M J; de Kruijff, Ben; Höppener, Jo W M; Antoinette Killian, J

    2006-02-24

    Amyloid deposits in the pancreatic islets of Langerhans are thought to be a main factor responsible for death of the insulin-producing islet beta-cells in type 2 diabetes. It is hypothesized that beta-cell death is related to interaction of the 37 amino acid residue human islet amyloid polypeptide (hIAPP), the major constituent of islet amyloid, with cellular membranes. However, the mechanism of hIAPP-membrane interactions is largely unknown. Here, we study the nature and the molecular details of the initial step of hIAPP-membrane interactions by using the monolayer technique. It is shown that both freshly dissolved hIAPP and the non-amyloidogenic mouse IAPP (mIAPP) have a pronounced ability to insert into phospholipid monolayers, even at lipid packing conditions that exceed the conditions that occur in biological membranes. In contrast, the fibrillar form of hIAPP has lost the ability to insert. These results, combined with the observations that both the insertion kinetics and the dependence of insertion on the initial surface pressure are similar for freshly dissolved hIAPP and mIAPP, indicate that hIAPP inserts into phospholipid monolayers most likely as a monomer. In addition, our results suggest that the N-terminal part of hIAPP, which is nearly identical with that of mIAPP, is largely responsible for insertion. This is supported by experiments with hIAPP fragments, which show that a peptide consisting of the 19 N-terminal residues of hIAPP efficiently inserts into phospholipid monolayers, whereas an amyloidogenic decapeptide, consisting of residues 20-29 of hIAPP, inserts much less efficiently. The results obtained here suggest that hIAPP monomers might insert with high efficiency in biological membranes in vivo. This process could play an important role as a first step in hIAPP-induced membrane damage in type 2 diabetes. PMID:16403520

  11. Increased expression of toll-like receptor 4 and inflammatory cytokines, interleukin-6 in particular, in islets from a mouse model of obesity and type 2 diabetes

    DEFF Research Database (Denmark)

    Ladefoged, Mette; Buschard, Karsten; Hansen, Ann Maria Kruse

    2013-01-01

    Toll-like receptor 4 (TLR4) has received much attention in the recent years due to its role in development of insulin resistance in type 2 diabetes mellitus. Its expression is elevated in fat and muscle from insulin-resistant mice. Several cells of the pancreatic islets, including β-cells and res......Toll-like receptor 4 (TLR4) has received much attention in the recent years due to its role in development of insulin resistance in type 2 diabetes mellitus. Its expression is elevated in fat and muscle from insulin-resistant mice. Several cells of the pancreatic islets, including β...

  12. Responses against islet antigens in NOD mice are prevented by tolerance to proinsulin but not IGRP

    OpenAIRE

    Krishnamurthy, Balasubramanian; Nadine L Dudek; McKenzie, Mark D.; Anthony W Purcell; Brooks, Andrew G.; Gellert, Shane; Colman, Peter G; Harrison, Leonard C.; Lew, Andrew M.; Helen E. Thomas; Kay, Thomas W.H.

    2006-01-01

    Type 1 diabetes (T1D) is characterized by immune responses against several autoantigens expressed in pancreatic β cells. T cells specific for proinsulin and islet-specific glucose-6-phosphatase catalytic subunit–related protein (IGRP) can induce T1D in NOD mice. However, whether immune responses to multiple autoantigens are caused by spreading from one to another or whether they develop independently of each other is unknown. As cytotoxic T cells specific for IGRP were not detected in transge...

  13. Different pancreatic islet β cell function index for the evaluation of glucose metabolism in type 2 diabetes%不同胰岛β细胞功能指数对评价2型糖尿病糖代谢的作用

    Institute of Scientific and Technical Information of China (English)

    辛欢欢; 郗光霞; 陈瑶; 赵媛媛; 郭清华; 焦云红; 张学力

    2012-01-01

    目的 探讨不同胰岛β细胞功能指数评价不同病程2型糖尿病(T2DM)患者糖代谢的作用.方法 选取无糖尿病家族史的糖耐量正常者48例(对照组)和T2DM患者182例,T2DM患者根据病程不同分为<5年组(DM<5组)74例、5~10年组(DM5 ~10组)51例和>10年组(DM>10组)57例.行口服葡萄糖耐量试验(OGTT)和胰岛素释放试验,以稳态模型评估的胰岛素抵抗指数(HOMA-IR)和全身胰岛素敏感指数[ISI(Matsuda)]评估胰岛素敏感性;以早期胰岛素分泌功能指数(△I30/△G30)和葡萄糖处置指数(DI)评估胰岛β细胞功能.结果 DM<5组、DM5~10组和DM>10组HOMA-IR较对照组升高(8.78±7.12、8.08±3.67、7.84±5.08比4.76±3.43,P< 0.05),ISI(Matsuda)较对照组降低(46.78±29.00、36.71±16.67、38.86±21.72比61.13±32.08,P<0.05),DM<5组、DM5~10组和DM>10组比较差异无统计学意义(P>0.05).DM<5组、DM5~10组和DM>10组△I30/△G30和DI均较对照组降低[△I30/△G30:(68.41±361.52)、(4.31±3.42)、(7.70±5.78) mU/mmol比(92.65±309.29)mU/mmol; DI:0.0421±0.0123、0.0412±0.0123、0.0363±0.0116比0.1151±0.0236,P< 0.05]. DM<5组、DM5-10组和DM>10组△I30/△G30比较差异无统计学意义(P>0.05);与DM<5组和DM5~10组比较,DM>10组DI显著降低(P<0.05).结论 HOMA-IR、ISI(Matsuda)、△I30/△G30对评价不同病程胰岛素抵抗程度敏感性不高;DI能更早地反映胰岛β细胞对葡萄糖的利用,调节血糖稳态能力的变化.%Objective To assess the role of the different pancreatic islet β cell function index in the evaluation of glucose metabolism in different duration of type 2 diabetes mellitus (T2DM).Methods Normal glucose tolerance subjects without diabetes family history (NC group,48 cases) and T2DM patients (182 cases) were enrolled.The T2DM patients were divided into three groups:less than 5 years group (DM <5 group,74 cases),5-10 years group (DM5-10 group,51 cases) and more

  14. Pancreatic Tuberculosis or Autoimmune Pancreatitis

    Directory of Open Access Journals (Sweden)

    Ayesha Salahuddin

    2014-01-01

    Full Text Available Introduction. Isolated pancreatic and peripancreatic tuberculosis is a challenging diagnosis due to its rarity and variable presentation. Pancreatic tuberculosis can mimic pancreatic carcinoma. Similarly, autoimmune pancreatitis can appear as a focal lesion resembling pancreatic malignancy. Endoscopic ultrasound-guided fine needle aspiration provides an effective tool for differentiating between benign and malignant pancreatic lesions. The immune processes involved in immunoglobulin G4 related systemic diseases and tuberculosis appear to have some similarities. Case Report. We report a case of a 59-year-old Southeast Asian male who presented with fever, weight loss, and obstructive jaundice. CT scan revealed pancreatic mass and enlarged peripancreatic lymph nodes. Endoscopic ultrasound-guided fine needle aspiration confirmed the presence of mycobacterium tuberculosis. Patient also had high immunoglobulin G4 levels suggestive of autoimmune pancreatitis. He was started on antituberculosis medications and steroids. Clinically, he responded to treatment. Follow-up imaging showed findings suggestive of chronic pancreatitis. Discussion. Pancreatic tuberculosis and autoimmune pancreatitis can mimic pancreatic malignancy. Accurate diagnosis is imperative as unnecessary surgical intervention can be avoided. Endoscopic ultrasound-guided fine needle aspiration seems to be the diagnostic test of choice for pancreatic masses. Long-term follow-up is warranted in cases of chronic pancreatitis.

  15. Defective secretion of islet hormones in chromogranin-B deficient mice.

    Directory of Open Access Journals (Sweden)

    Stefanie Obermüller

    Full Text Available Granins are major constituents of dense-core secretory granules in neuroendocrine cells, but their function is still a matter of debate. Work in cell lines has suggested that the most abundant and ubiquitously expressed granins, chromogranin A and B (CgA and CgB, are involved in granulogenesis and protein sorting. Here we report the generation and characterization of mice lacking chromogranin B (CgB-ko, which were viable and fertile. Unlike neuroendocrine tissues, pancreatic islets of these animals lacked compensatory changes in other granins and were therefore analyzed in detail. Stimulated secretion of insulin, glucagon and somatostatin was reduced in CgB-ko islets, in parallel with somewhat impaired glucose clearance and reduced insulin release, but normal insulin sensitivity in vivo. CgB-ko islets lacked specifically the rapid initial phase of stimulated secretion, had elevated basal insulin release, and stored and released twice as much proinsulin as wildtype (wt islets. Stimulated release of glucagon and somatostatin was reduced as well. Surprisingly, biogenesis, morphology and function of insulin granules were normal, and no differences were found with regard to beta-cell stimulus-secretion coupling. We conclude that CgB is not required for normal insulin granule biogenesis or maintenance in vivo, but is essential for adequate secretion of islet hormones. Consequentially CgB-ko animals display some, but not all, hallmarks of human type-2 diabetes. However, the molecular mechanisms underlying this defect remain to be determined.

  16. Improvement of islet engrafts by enhanced angiogenesis and microparticle-mediated oxygenation.

    Science.gov (United States)

    Montazeri, Leila; Hojjati-Emami, Shahriar; Bonakdar, Shahin; Tahamtani, Yaser; Hajizadeh-Saffar, Ensiyeh; Noori-Keshtkar, Marjan; Najar-Asl, Mostafa; Ashtiani, Mohammad Kazemi; Baharvand, Hossein

    2016-05-01

    A major hindrance in islet transplantation as a feasible therapeutic approach for patients with type 1 diabetes is the insufficient oxygenation of the grafts, which results in cell death in portions of the implant. Here we address this limitation through the application of oxygen-generating microparticles (MP) and a fibrin-conjugated heparin/VEGF collagen scaffold to support cell survival by using a β cell line and pancreatic rat islets. MP are composed of a polyvinylpyrrolidone/hydrogen peroxide (PVP/H2O2) core and poly(D,L-lactide-co-glycolide) (PLGA) shell, along with immobilized catalase on the shell. The presence of MP is sufficient to reduce hypoxia-induced cell dysfunction and death for both cell types, resulting in localization of hypoxia-inducible factor (HIF-1α) into the cytoplasm and enhanced metabolic function. After co-transplantation of MP and a reduced islet mass (250 islet equivalents) within an angiogenic scaffold in the omental pouch of streptozotocin-induced diabetic nude mice, we have observed significantly promoted graft function as evidenced by improved blood glucose levels, body weight, glucose tolerance, serum C-peptide, and graft revascularization. These results suggest that the developed platform has great potential to enhance the efficacy for implants in cases where the cell dosage is critical for efficacy, such as islet transplantation and ischemic tissues.

  17. Complicated Pancreatitis

    NARCIS (Netherlands)

    Bakker, O.J.

    2015-01-01

    Research questions addressed in this thesis: What is the accuracy of serum blood urea nitrogen as early predictor of complicated pancreatitis? ; What is difference in clinical outcome between patients with pancreatic parenchymal necrosis and patients with extrapancreatic necrosis without necrosis

  18. Experimental studies on islet isolation and islet graft function

    NARCIS (Netherlands)

    Suijlichem, Paul Tjepke Robert van

    1994-01-01

    In the first part of the introduction (Chapter 1) of this thesis an overview of the numerous techniques used in islet isolation procedures is presented. The differing lines of approach for the dissociation of the pancreas which have been applied, and are still being further developed, indicate that

  19. Pain management in chronic pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Cathia Gachago; Peter V Draganov

    2008-01-01

    Abdominal pain is a major clinical problem in patients with chronic pancreatitis.The cause of pain is usually multifactorial with a complex interplay of factors contributing to a varying degree to the pain in an individual patient and,therefore,a rigid standardized approach for pain control tends to lead to suboptimal results.Pain management usually proceeds in a stepwise approach beginning with general lifestyle recommendations,low fat diet,alcohol and smoking cessation are encouraged.Analgesics alone are needed in almost all patients.Maneuvers aimed at suppression of pancreatic secretion are routinely tried.Patients with ongoing symptoms may be candidates for more invasive options such as endoscopic therapy,and resective or drainage surgery.The role of pain modifying agents (antidepressants,gabapentin,peregabalin),celiac plexus block,antioxidants,octreotide and total pancreatectomy with islet cell auto transplantation remains to be determined.

  20. Complicated Pancreatitis

    OpenAIRE

    Bakker, O.J.

    2015-01-01

    Research questions addressed in this thesis: What is the accuracy of serum blood urea nitrogen as early predictor of complicated pancreatitis? ; What is difference in clinical outcome between patients with pancreatic parenchymal necrosis and patients with extrapancreatic necrosis without necrosis of the pancreatic parenchyma? ; What is the impact of organ failure on mortality in necrotizing pancreatitis? ; Based on individual patient data from randomized trials, does early enteral tube feedin...

  1. Childhood pancreatitis.

    Science.gov (United States)

    Uretsky, G; Goldschmiedt, M; James, K

    1999-05-01

    Acute pancreatitis is a rare finding in childhood but probably more common than is generally realized. This condition should be considered in the evaluation of children with vomiting and abdominal pain, because it can cause significant morbidity and mortality. Clinical suspicion is required to make the diagnosis, especially when the serum amylase concentration is normal. Recurrent pancreatitis may be familial as a result of inherited biochemical or anatomic abnormalities. Patients with hereditary pancreatitis are at high risk for pancreatic cancer.

  2. Multimodality treatment of unresectable hepatic metastases from pancreatic glucagonoma

    Directory of Open Access Journals (Sweden)

    Giovanni Bernardo

    2009-07-01

    Full Text Available Glucagonomas are pancreatic islet cell tumors arising from the alpha cells which belong to neuroendocrine tumors. They frequently metastasize to the liver. We report the case of a 52- year old man with a pancreatic glucagonoma with synchronous multiple liver metastases treated by surgery, transarterial chemoembolization, percutaneous radiofrequency thermal ablation and long-acting octreotide. Our report confirms that a multimodal approach is very effective in patients with unresectable liver metastases from pancreatic endocrine tumors providing long-lasting palliation and probably prolonging survival.

  3. 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 (parginine in islets cultured in HARVs. While nitrogenous compound analysis indicated a ubiquitous reliance upon glutamine in all experimental groups, arginine was converted to ornithine at a two-fold greater rate in the islets cultured in the HARV microgravity model system (p<0.05). These studies demonstrate alterations in LPS induced TNF-alpha 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.

  4. Production of islet-like insulin-producing cell clusters in vitro from adipose-derived stem cells

    Directory of Open Access Journals (Sweden)

    Loan Thi-Tung Dang

    2015-01-01

    Full Text Available Diabetes mellitus is a high incidence disease that has increased rapidly in recent years. Many new therapies are being studied and developed in order to find an effective treatment. An ideal candidate is stem cell therapy. In this study, we investigated the differentiation of adipose derived stem cells (ADSCs into pseudo-islets in defined medium in vitro, to produce large quantities of insulin-producing cells (IPCs for transplantation. ADSCs isolated from adipose tissue were induced to differentiate into islet-like insulin-producing cell clusters in vitro by inducing medium DMEM/F12 containing nicotinamide, N2, B27, bFGF, and insulin-transferrin-selenite (ITS. Differentiated cells were analyzed for properties of IPCs, including storage of Zn2+ by dithizone staining, insulin production by ELISA and immunochemistry, and beta cell-related gene expression by reverse transcriptase PCR. The results showed that after 2 weeks of differentiation, the ADSCs aggregated into cell clusters, and after 4 weeks they formed islets, 50 and ndash;400 micrometers in diameter. These islet cells exhibited characteristics of pancreatic beta cells as they were positive for dithizone staining, expressed insulin in vitro and C-peptide in the cytoplasm, and expressed pancreatic beta cell-specific genes, including Pdx-1, NeuroD, and Ngn3. These results demonstrate that ADSCs can be used to produce a large number of functional islets for research as well as application. [Biomed Res Ther 2015; 2(1.000: 184-192

  5. SURGICAL TREATMENT OF PAIN IN CHRONIC PANCREATITIS:STUDIES OF 111 PATIENTS

    Institute of Scientific and Technical Information of China (English)

    D. Guinier; P. Mathieu; B. Heyd; G. Mantion

    2004-01-01

    Objective Evaluation of the efficacy of pancreatic resections for the treatment of chronic pains during chronic pancreatitis. Methods Retrospective study of inpatients for chronic pancreatitis between 1982 to 2000. Purpose of admission, morphological changes, treatments and results were evaluated. Results 142 patients were admitted for chronic pancreatitis. 111 patients suffered from chronic pains, due to morphological changes such as pseudocysts, inflammatory masses in the head, dilated pancreatic ducts, biliary or duodenal compressions. Denervations were never efficient, pancreatic resections achieved relief of pain in up to 75% of cases and drainages were efficient in 52% of cases. Conclusions Pancreatic resections during chronic pancreatitis seem to be the most efficient treatment of chronic pains. New techniques such as duodenum-preserving head resection or total pancreatectomy with islet autotransplantation should improve these results.

  6. siRNA Specific to Pdx-1 Disturbed the Formation of the Islet in Early Zebrafish Embryos

    Institute of Scientific and Technical Information of China (English)

    CHEN Shen; HUANG Jintao; YUAN Guangnfing; CHEN Qian; HUANG Nannan; XIE Fukang

    2007-01-01

    Pdx-1, an important transcription factor highlighting in the early pancreatic development,islet functions and pancreatic disorders, needs to be more investigated in zebrafish, and siRNA is still seldom applied in zebrafish embryo-related research.Our aim was to explore the role of pdx-1 in pan-creatic development of zebrafish embryos by using siRNA approach. Microinjection, reverse tran-scriptase-PCR (RT-PCR), in situ hybridization and immunofluorescent staining were used in this re-search, and the morphology of the islet in normal zebrafish embryos, and in those treated with the siRNA specific to pdx-1 (siPDX-1) or siGFP was observed and compared. The expression of pdx-1 was detected in the stages of 1-cell, 2-cell, 4-cell, 8-cell, 16-cell, 16-hour by RT-PCT. The in situ hy-bridization and immunofluorescent staining results showed that siPDX-I disturbed the formation of the islet in zebrafish embryos. Pdx-1 played multiple roles in maintaining the phenotype of the islet during embryogenesis in zebrafish.

  7. 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.

  8. A chemical energy approach of avascular tumor growth: multiscale modeling and qualitative results.

    Science.gov (United States)

    Ampatzoglou, Pantelis; Dassios, George; Hadjinicolaou, Maria; Kourea, Helen P; Vrahatis, Michael N

    2015-01-01

    In the present manuscript we propose a lattice free multiscale model for avascular tumor growth that takes into account the biochemical environment, mitosis, necrosis, cellular signaling and cellular mechanics. This model extends analogous approaches by assuming a function that incorporates the biochemical energy level of the tumor cells and a mechanism that simulates the behavior of cancer stem cells. Numerical simulations of the model are used to investigate the morphology of the tumor at the avascular phase. The obtained results show similar characteristics with those observed in clinical data in the case of the Ductal Carcinoma In Situ (DCIS) of the breast. PMID:26558163

  9. Avascular necrosis of bilateral femoral heads in a patient with Fabry's disease.

    LENUS (Irish Health Repository)

    O'Neill, Francis

    2012-07-13

    The underlying cause of avascular necrosis (AVN) of the femoral head is often not apparent. We report the case of a 26 year old builder with a four month history of bilateral hip pain, and a diagnosis of bilateral femoral head avascular necrosis. Fabry\\'s disease was identified as the probable cause. Since 2001, enzyme replacement therapy for Fabry\\'s disease has become available, with a potential to influence the disease process, and this is of potential importance to clinicians treating AVN.

  10. Islet Product Characteristics and Factors Related to Successful Human Islet Transplantation From the Collaborative Islet Transplant Registry (CITR) 1999–2010

    OpenAIRE

    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

    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 

  11. Decreased cholinergic stimulation of insulin secretion by islets from rats fed a low protein diet is associated with reduced protein kinase calpha expression.

    Science.gov (United States)

    Ferreira, Fabiano; Filiputti, Eliane; Arantes, Vanessa C; Stoppiglia, Luis F; Araújo, Eliana P; Delghingaro-Augusto, Viviane; Latorraca, Márcia Q; Toyama, Marcos H; Boschero, Antonio C; Carneiro, Everardo M

    2003-03-01

    Undernutrition has been shown to affect the autonomic nervous system, leading to permanent alterations in insulin secretion. To understand these interactions better, we investigated the effects of carbamylcholine (CCh) and phorbol 12-myristate 13-acetate (PMA) on insulin secretion in pancreatic islets from rats fed a normal (17%; NP) or low (6%; LP) protein diet for 8 wk. Isolated islets were incubated for 1 h in Krebs-bicarbonate solution containing 8.3 mmol glucose/L, with or without PMA (400 nmol/L) and CCh. Increasing concentrations of CCh (0.1-1000 micro mol/L) dose dependently increased insulin secretion by islets from both groups of rats. However, insulin secretion by islets from rats fed the NP diet was significantly higher than that of rats fed the LP diet, and the dose-response curve to CCh was shifted to the right in islets from rats fed LP with a 50% effective concentration (EC(50)) of 2.15 +/- 0.7 and 4.64 +/- 0.1 micro mol CCh/L in islets of rats fed NP and LP diets, respectively (P < 0.05). PMA-induced insulin secretion was higher in islets of rats fed NP compared with those fed LP. Western blotting revealed that the protein kinase (PK)Calpha and phospholipase (PL)Cbeta(1) contents of islets of rats fed LP were 30% lower than those of islets of rats fed NP (P < 0.05). In addition, PKCalpha mRNA expression was reduced by 50% in islets from rats fed LP. In conclusion, a reduced expression of PKCalpha and PLCbeta(1) may be involved in the decreased insulin secretion by islets from LP rats after stimulation with CCh and PMA. PMID:12612139

  12. 脐带源间充质干细胞与大鼠胰腺细胞共培养向胰岛样细胞分化及移植治疗1型糖尿病%Islet-like cells derived from mesenchymal stem cells in Wharton's Jelly of the human umbilical cord co-cultured with rat pancreatic cells for transplantation to control type Ⅰ diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    王广宇; 赵芳; 郝永蕾; 朱旅云; 李晓玲; 胡丽叶; 马利成; 单巍; 杨少玲

    2011-01-01

    BACKGROUND: Mesenchymal stem cells in Wharton's Jelly of the human umbilical cord can induce differentiation into islet-like cells.OBJECTIVE: To verify the possibility of human umbilical cord derived mesenchymal stem cells co-cultured with rat pancreatic cells differentiate into islet-like cells, and to observe the effects of transplantation of islet-like cells on blood glucose of diabetic rats.METHODS: Mesenchymal stem cells in Wharton's Jelly of the human umbilical cord was separated, induced, passaged, and co-cultured with pancreatic cells to induce differentiation into islet-like clusters. Rats were divided into the normal control, model and experimental groups. Rats in the model group were prepared for diabetic models, and those in the experimental group were transplanted islet-like cells after model preparation. RESULTS AND CONCLUSION: There were cells crawled out of cultured Wharton's Jelly of the human umbilical cord, and morphology of adhered cells turned into fusiform shape at 7 days. The isolated cells are characterized by expressing specific surface markers of mesenchymal stem cells, such as CD44, CD29, CD105, but not expressing CD34, CD45 or CD14. The cells were strongly stained by PDX-1 and human insulin at 7 and 10 days. Compared with the simple culture group, the expression of human insulin and concentration of C-peptide were obviously increased; PDX-1 and human insulin mRNA expressions were highly expressed at 7 and 10 days after induction. Compared with the model group, the streptozotocin test of rats in the experimental group was obvious decreased (P < 0.01), but extremely higher than that of the normal control group at 1 week after transplantation (P < 0.01). Brdu positive nuclei and insulin positive kytoplasms could be seen in the experimental group at 8 weeks after transplantation. The results demonstrated that, umbilical cord derived mesenchymal stem cells existed in Wharton's Jelly. The co-cultured cells promote mesenchymal stem cells

  13. Hereditary pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Richard M Charnley

    2003-01-01

    Hereditary pancreatitis is an autosomal dominant condition,which results in recurrent attacks of acute pancreatitis,progressing to chronic pancreatitis often at a young age.The majority of patients with hereditary pancreatitis expressone of two mutations (R122H or N29I) in the cationictrypsinogen gene (PRSS1 gene). It has been hypothesisedthat one of these mutations, the R122H mutation causespancreatitis by altering a trypsin recognition site sopreventing deactivation of trypsin within the pancreas andprolonging its action, resulting in autodigestion. Families withthese two mutations have been identified in many countriesand there are also other rarer mutations, which have alsobeen linked to hereditary pancreatitis.Patients with hereditary pancreatitis present in the sameway as those with sporadic pancreatitis but at an earlierage. It is common for patients to remain undiagnosed formany years, particularly ifthey present with non-specificsymptoms. Hereditary pancreatitis should always beconsidered in patients who present with recurrent pancreatitiswith a family history of pancreatic disease. If patients withthe 2 common mutations are compared, those with theR122H mutation are more likely to present at a younger ageand are more likely to require surgical intervention than thosewith N29I. Hereditary pancreatitis carries a 40 % lifetimerisk of pancreatic cancer with those patients aged between50 to 70 being most at risk in whom screening tests maybecome important.

  14. 4-Phenylbutyric Acid Attenuates Pancreatic Beta-Cell Injury in Rats with Experimental Severe Acute Pancreatitis.

    Science.gov (United States)

    Hong, Yu-Pu; Guo, Wen-Yi; Wang, Wei-Xing; Zhao, Liang; Xiang, Ming-Wei; Mei, Fang-Chao; Abliz, Ablikim; Hu, Peng; Deng, Wen-Hong; Yu, Jia

    2016-01-01

    Endoplasmic reticulum (ER) stress is a particular process with an imbalance of homeostasis, which plays an important role in pancreatitis, but little is known about how ER stress is implicated in severe acute pancreatitis (SAP) induced pancreatic beta-cell injury. To investigate the effect of 4-phenylbutyric acid (4-PBA) on the beta-cell injury following SAP and the underlying mechanism, twenty-four Sprague-Dawley rats were randomly divided into sham-operation (SO) group, SAP model group, and 4-PBA treatment group. SAP model was induced by infusion of 5% sodium taurocholate into the biliopancreatic duct. 4-PBA or normal saline was injected intraperitoneally for 3 days in respective group before successful modeling. Results showed that 4-PBA attenuated the following: (1) pancreas and islet pathological injuries, (2) serum TNF-α and IL-1β, (3) serum insulin and glucose, (4) beta-cell ultrastructural changes, (5) ER stress markers (BiP, ORP150, and CHOP), Caspase-3, and insulin expression in islet. These results suggested that 4-PBA mitigates pancreatic beta-cell injury and endocrine disorder in SAP, presumably because of its role in inhibiting excessive endoplasmic reticulum stress. This may serve as a new therapeutic target for reducing pancreatic beta-cell injury and endocrine disorder in SAP upon 4-PBA treatment. PMID:27656209

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

    Science.gov (United States)

    Bacos, Karl; Gillberg, Linn; Volkov, Petr; Olsson, Anders H; Hansen, Torben; Pedersen, Oluf; Gjesing, Anette Prior; Eiberg, Hans; Tuomi, Tiinamaija; Almgren, Peter; Groop, Leif; Eliasson, Lena; Vaag, Allan; Dayeh, Tasnim; Ling, Charlotte

    2016-01-01

    Aging associates with impaired pancreatic islet function and increased type 2 diabetes (T2D) risk. Here we examine whether age-related epigenetic changes affect human islet function and if blood-based epigenetic biomarkers reflect these changes and associate with future T2D. We analyse DNA methylation genome-wide in islets from 87 non-diabetic donors, aged 26–74 years. Aging associates with increased DNA methylation of 241 sites. These sites cover loci previously associated with T2D, for example, KLF14. Blood-based epigenetic biomarkers reflect age-related methylation changes in 83 genes 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 demonstrate that blood-based epigenetic biomarkers reflect age-related DNA methylation changes in human islets, and associate with insulin secretion in vivo and T2D. PMID:27029739

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

    Science.gov (United States)

    Bacos, Karl; Gillberg, Linn; Volkov, Petr; Olsson, Anders H; Hansen, Torben; Pedersen, Oluf; Gjesing, Anette Prior; Eiberg, Hans; Tuomi, Tiinamaija; Almgren, Peter; Groop, Leif; Eliasson, Lena; Vaag, Allan; Dayeh, Tasnim; Ling, Charlotte

    2016-01-01

    Aging associates with impaired pancreatic islet function and increased type 2 diabetes (T2D) risk. Here we examine whether age-related epigenetic changes affect human islet function and if blood-based epigenetic biomarkers reflect these changes and associate with future T2D. We analyse DNA methylation genome-wide in islets from 87 non-diabetic donors, aged 26-74 years. Aging associates with increased DNA methylation of 241 sites. These sites cover loci previously associated with T2D, for example, KLF14. Blood-based epigenetic biomarkers reflect age-related methylation changes in 83 genes 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 demonstrate that blood-based epigenetic biomarkers reflect age-related DNA methylation changes in human islets, and associate with insulin secretion in vivo and T2D. PMID:27029739

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

    Science.gov (United States)

    Bacos, Karl; Gillberg, Linn; Volkov, Petr; Olsson, Anders H; Hansen, Torben; Pedersen, Oluf; Gjesing, Anette Prior; Eiberg, Hans; Tuomi, Tiinamaija; Almgren, Peter; Groop, Leif; Eliasson, Lena; Vaag, Allan; Dayeh, Tasnim; Ling, Charlotte

    2016-03-31

    Aging associates with impaired pancreatic islet function and increased type 2 diabetes (T2D) risk. Here we examine whether age-related epigenetic changes affect human islet function and if blood-based epigenetic biomarkers reflect these changes and associate with future T2D. We analyse DNA methylation genome-wide in islets from 87 non-diabetic donors, aged 26-74 years. Aging associates with increased DNA methylation of 241 sites. These sites cover loci previously associated with T2D, for example, KLF14. Blood-based epigenetic biomarkers reflect age-related methylation changes in 83 genes 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 demonstrate that blood-based epigenetic biomarkers reflect age-related DNA methylation changes in human islets, and associate with insulin secretion in vivo and T2D.

  18. Compartmentalization of GABA synthesis by GAD67 differs between pancreatic beta cells and neurons

    DEFF Research Database (Denmark)

    Kanaani, Jamil; Cianciaruso, Chiara; Phelps, Edward A;

    2015-01-01

    The inhibitory neurotransmitter GABA is synthesized by the enzyme glutamic acid decarboxylase (GAD) in neurons and in pancreatic β-cells in islets of Langerhans where it functions as a paracrine and autocrine signaling molecule regulating the function of islet endocrine cells. The localization...... of the two non-allelic isoforms GAD65 and GAD67 to vesicular membranes is important for rapid delivery and accumulation of GABA for regulated secretion. While the membrane anchoring and trafficking of GAD65 are mediated by intrinsic hydrophobic modifications, GAD67 remains hydrophilic, and yet is targeted...... accumulation of newly synthesized GABA for regulated secretion and fine tuning of GABA-signaling in islets of Langerhans....

  19. Avascular necrosis of the distal phalangeal epiphysis following physeal fracture: a case report.

    Science.gov (United States)

    Nissenbaum, M

    1999-05-01

    Avascular necrosis of the distal phalangeal epiphysis following an unrecognized angulated Salter II fracture of the distal phalanx treated by open reduction and internal fixation resulted in premature closure of the growth plate and mild shortening. The epiphysis itself revascularized and good function of the distal interphalangeal joint was maintained.

  20. Islet distribution of Peptide YY and its regulatory role in primary mouse islets and immortalised rodent and human beta-cell function and survival.

    Science.gov (United States)

    Khan, Dawood; Vasu, Srividya; Moffett, R Charlotte; Irwin, Nigel; Flatt, Peter R

    2016-11-15

    Recent evidence suggests that the classic gut peptide, Peptide YY (PYY), could play a fundamental role in endocrine pancreatic function. In the present study expression of PYY and its NPY receptors on mouse islets and immortalised rodent and human beta-cells was examined together with the effects of both major circulating forms of PYY, namely PYY(1-36) and PYY(3-36), on beta-cell function, murine islet adaptions to insulin deficiency/resistance, as well as direct effects on cultured beta-cell proliferation and apoptosis. In vivo administration of PYY(3-36), but not PYY(1-36), markedly (p food intake in overnight fasted mice. Neither form of PYY affected glucose disposal or insulin secretion following an i.p. glucose challenge. However, in vitro, PYY(1-36) and PYY(3-36) inhibited (p preservation of beta-cell mass in diabetes. PMID:27465830