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Sample records for intraportal islet transplantation

  1. Role of Natural Killer Cells in the Innate Immune System After Intraportal Islet Transplantation in Mice.

    Science.gov (United States)

    Saeki, Y; Ishiyama, K; Ishida, N; Tanaka, Y; Ohdan, H

    Both liver natural killer (NK) and NK T cells of the innate immune system play a crucial role in islet graft loss after intraportal islet transplantation, although a relationship between NK and NK T cells in islet loss has not been proven. In this study, we investigated the role of NK cells in the innate immune system in islet graft loss after intraportal islet transplantation. To investigate the involvement of liver NK cells in islet destruction, we assessed the differences in graft survival after intraportal islet transplantation between CD1d -/- diabetic mice and NK cell-depleted CD1d -/- diabetic mice. The transplantation of 400 islets into the liver was sufficient to reverse hyperglycemia in wild-type diabetic mice (100%, 4/4). However, normoglycemia could not be achieved when 200 islets were transplanted (0%, 0/4). In contrast, intraportal transplantation of 200 islets in NK cell-depleted CD1d -/- diabetic mice ameliorated hyperglycemia in 71% of cases (5/7), whereas transplantation of the same number of islets in CD1d -/- diabetic mice did not (0%, 0/4). Histologic findings also confirmed that intact islets were observed in NK cell-depleted CD1d -/- diabetic mice, but were difficult to observe in CD1d -/- diabetic mice. The involvement of liver NK cells in the innate immune system related to islet graft loss after intraportal islet transplantation is revealed by improved graft survival and function in NK cell-depleted CD1d -/- diabetic mice. Our data reveal that regulation of NK cell activity is particularly important when insufficient islet numbers are used for transplantation. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Feasibility of islet magnetic resonance imaging using ferumoxytol in intraportal islet transplantation.

    Science.gov (United States)

    Jin, Sang-Man; Oh, Seung-Hoon; Oh, Bae Jun; Shim, Wooyoung; Choi, Jin Myung; Yoo, Dongkyeom; Hwang, Yong Hwa; Lee, Jung Hee; Lee, Dong Yun; Kim, Jae Hyeon

    2015-06-01

    There is a clinical need for an alternative labeling agent for magnetic resonance imaging (MRI) in islet transplantation. We aimed to evaluate the feasibility of islet MRI using ferumoxytol, which is the only clinically-available ultrasmall superparamagnetic iron oxide. We compared islet function and viability of control islets and islets labeled with ferumoxytol and/or a heparin-protamine complex (HPF). Efficacy of ferumoxytol labeling was assessed in both ex vivo and in vivo models. Labeling for 48 h with HPF, but not up to 800 μg/mL ferumoxytol, deranged ex vivo islet viability and function. The T2∗ relaxation time was optimal when islets were labeled with 800 μg/mL of ferumoxytol for 48 h. Prussian blue stain, iron content assay, transmission electron microscopy (TEM) supported internalization of ferumoxytol particles. However, the labeling intensity in the ex vivo MRI of islets labeled with ferumoxytol was much weaker than that of islets labeled with ferucarbotran. In syngeneic intraportal islet transplantation, there was a correlation between the total area of visualized islets and the transplanted islet mass. In conclusion, islet MRI using ferumoxytol was feasible in terms of in vitro and in vivo efficacy and safety. However, the weak labeling efficacy is still a hurdle for the clinical application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Effect of nicotinamide on early graft failure following intraportal islet transplantation

    Science.gov (United States)

    Jung, Da-Yeon; Park, Jae Berm; Joo, Sung-Yeon; Joh, Jae-Won; Kwon, Choon-Hyuck; Kwon, Ghee-Young

    2009-01-01

    Intraportal islet transplantation (IPIT) may potentially cure Type 1 diabetes mellitus; however, graft failure in the early post-transplantation period presents a major obstacle. In this study, we tested the ability of nicotinamide to prevent early islet destruction in a syngeneic mouse model. Mice (C57BL/6) with chemically-induced diabetes received intraportal transplants of syngeneic islet tissue in various doses. Islets were cultured for 24 h in medium with or without 10 mM nicotinamide supplementation. Following IPIT, islet function was confirmed by an intraperitoneal glucose tolerance test (IPGTT) and hepatectomy. The effects of nicotinamide were evaluated by blood glucose concentration, serum monocyte chemoattractant protein-1 (MCP-1) concentration, and immunohistology at 3 h and 24 h after IPIT. Among the various islet doses, an infusion of 300 syngeneic islets treated with nicotinamide exhibited the greatest differences in glucose tolerance between recipients of treated and untreated (i.e., control) islets. One day after 300 islet equivalent (IEQ) transplantation, islets treated with nicotinamide were better granulated than the untreated islets (P = 0.01), and the recipients displayed a slight decrease in serum MCP-1 concentration, as compared to controls. After 15 days, recipients of nicotinamide-pretreated islets showed higher levels of graft function (as measured by IPGTT) than controls. The pretreatment also prolonged graft survival (> 100 days) and function; these were confirmed by partial hepatectomy, which led to the recurrence of diabetes. Pretreatment of islet grafts with nicotinamide may prevent their deterioration on the early period following IPIT in a syngeneic mouse model. PMID:19641379

  4. Human Recombinant Antithrombin (ATryn®) Administration Improves Survival and Prevents Intravascular Coagulation After Intraportal Islet Transplantation in a Piglet Model.

    Science.gov (United States)

    Gmyr, Valery; Bonner, Caroline; Moerman, Ericka; Tournoys, Antoine; Delalleau, Nathalie; Quenon, Audrey; Thevenet, Julien; Chetboun, Mikael; Kerr-Conte, Julie; Pattou, François; Hubert, Thomas; Jourdain, Merce

    2017-02-16

    Human islet transplantation is a viable treatment option for type 1 diabetes mellitus (T1DM). However, pancreatic islet inflammation after transplantation induced by innate immune responses is likely to hinder graft function. This is mediated by incompatibility between islets and the blood interface, known as instant blood-mediated inflammatory reaction (IBMIR). Herein we hypothesized that portal venous administration of islet cells with human recombinant antithrombin (ATryn®), a serine protease inhibitor (serpin), which plays a central role in the physiological regulation of coagulation and exerts indirect anti-inflammatory activities, may offset coagulation abnormalities such as disseminated intravascular coagulation (DIC) and IBMIR. The current prospective, randomized experiment was conducted using an established preclinical pig model. Three groups were constituted for digested pancreatic tissue transplantation (0.15 ml/kg): control, NaCl 0.9% (n = 7); gold standard, heparin (25 UI/kg) (n = 7); and human recombinant ATryn® (500 UI/kg) (n = 7). Blood samples were collected over time (T0 to 24 h), and biochemical, coagulation, and inflammatory parameters were evaluated. In both the control and heparin groups, one animal died after a portal thrombosis, while no deaths occurred in the ATryn®-treated group. As expected, islet transplantation was associated with an increase in plasma IL-6 or TNF-α levels in all three groups. However, DIC was only observed in the control group, an effect that was suppressed after ATryn® administration. ATryn® administration increased antithrombin activity by 800%, which remained at 200% for the remaining period of the study, without any hemorrhagic complications. These studies suggest that coadministration of ATryn® and pancreatic islets via intraportal transplantation may be a valuable therapeutic approach for DIC without risk for islets and subjects.

  5. Human Recombinant Antithrombin (ATryn®) Administration Improves Survival and Prevents Intravascular Coagulation after Intraportal Islet Transplantation in a Piglet Model

    Science.gov (United States)

    Gmyr, Valery; Bonner, Caroline; Moerman, Ericka; Tournoys, Antoine; Delalleau, Nathalie; Quenon, Audrey; Thevenet, Julien; Chetboun, Mikael; Kerr-Conte, Julie; Pattou, François; Hubert, Thomas; Jourdain, Merce

    2017-01-01

    Human islet transplantation is a viable treatment option for type 1 diabetes mellitus (T1DM). However, pancreatic islet inflammation after transplantation induced by innate immune responses is likely to hinder graft function. This is mediated by incompatibility between islets and the blood interface, known as instant blood-mediated inflammatory reaction (IBMIR). Herein we hypothesized that portal venous administration of islet cells with human recombinant antithrombin (ATryn®), a serine protease inhibitor (serpin), which plays a central role in the physiological regulation of coagulation and exerts indirect anti-inflammatory activities, may offset coagulation abnormalities such as disseminated intravascular coagulation (DIC) and IBMIR. The current prospective, randomized experiment was conducted using an established preclinical pig model. Three groups were constituted for digested pancreatic tissue transplantation (0.15 ml/kg): control, NaCl 0.9% (n = 7); gold standard, heparin (25 UI/kg) (n = 7); and human recombinant ATryn® (500 UI/kg) (n = 7). Blood samples were collected over time (T0 to 24 h), and biochemical, coagulation, and inflammatory parameters were evaluated. In both the control and heparin groups, one animal died after a portal thrombosis, while no deaths occurred in the ATryn®-treated group. As expected, islet transplantation was associated with an increase in plasma IL-6 or TNF-α levels in all three groups. However, DIC was only observed in the control group, an effect that was suppressed after ATryn® administration. ATryn® administration increased antithrombin activity by 800%, which remained at 200% for the remaining period of the study, without any hemorrhagic complications. These studies suggest that coadministration of ATryn® and pancreatic islets via intraportal transplantation may be a valuable therapeutic approach for DIC without risk for islets and subjects. PMID:27938471

  6. Islet Transplantation

    Science.gov (United States)

    ... be successful. However, transplanting islet cells has several advantages over transplanting a pancreas. First, unlike the pancreas ... Email: Sign Up Thank you for signing up ' + ' '); $('.survey-form').show(); }, success: function (data) { $('#survey-errors').remove(); $('. ...

  7. Isolation, culture and intraportal transplantation of rat marrow stromal cell

    International Nuclear Information System (INIS)

    Wang Ping; Wang Jianhua; Yan Zhiping; Li Wentao; Lin Genlai; Hu Meiyu; Wang Yanhong

    2004-01-01

    Objective: To observe the tracing and evolution of marrow stromal cell (MSC) after intraportal transplantation into the liver of homogenous rats, and to provide experimental data for MSC differentiation to hepatocyte in vivo. Methods: The MSC was isolated from the leg bone marrow of adult SD rats, and purified by culture-expanded in vitro. Before transplantation, MSC was labeled with DAPI. Then 10 5 MSC were intraportally transplanted into the homogenous rat liver. Rats were killed at 2 hours and 1, 2, 3 and 4 weeks after transplantation. The cryosection samples of liver and lung were observed under fluorescence microscopy. Results: MSC in vitro culture had high ability of proliferation. Except 4 rats were dead because of abdominal bleeding or infection, other recipients were healthy until sacrificed. The implantation cells were detected by identifying the DAPI labeled MSC in the host livers, but not in the host lungs. Conclusion: Intraportal transplanted MSC could immigrate and survive in the host livers at least for 4 weeks. They could immigrate from the small branches of portal veins to hepatic parenchyma

  8. Pancreatic islet transplantation. Experimental and clinical aspects

    DEFF Research Database (Denmark)

    Yderstræde, Knud Bonnet

    1987-01-01

    The deteriorating complications of diabetes mellitus (i.e. nephropathy, neuropathy, and retinopathy) have encouraged several attempts of causal therapy apart from a diversity of insulin therapies. These attempts include whole organ or segmental pancreas transplantation. In recent years, increasing...... interest has been shown in transplantation of isolated islets either directly, introduced intraportally, intramuscularly, inter alia, or encapsulated in artificial devices providing an immuno-isolation. Clinical application has revealed promising results concerning the immunological aspects. However......, quantitative assessment points to a difficulty in achieving satisfactory amounts of islets to attain normoglycaemia. Work with fetal pancreata has shown these to possess a growth potential in vitro thus, possibly, aiding the quantification of islets in transplantation models. In the field of pancreatic islet...

  9. 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

  10. Inflammatory Response in Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Mazhar A. Kanak

    2014-01-01

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

  11. Preclinical evaluation of a 68Ga-labeled biotin analogue for applications in islet transplantation

    International Nuclear Information System (INIS)

    Eriksson, Olof; Carlsson, Fredrik; Blom, Elisabeth; Sundin, Anders; Långström, Bengt; Korsgren, Olle; Velikyan, Irina

    2012-01-01

    Introduction: Islet transplantation is a promising treatment for type 1 diabetes mellitus, but the fate of the cells after intraportal infusion is unclear. It is therefore imperative to develop novel techniques for noninvasive imaging and quantification of events following islet transplantation. Methods: Small islet-like microbeads, avidin-covered agarose resins (AARs), were used as a model system for islet transplantation. Capability for specific [ 68 Ga]Ga-DOTA-(PEG) 2 -biotin uptake and retention for either AARs or human islets conjugated with avidin by means of a heparin scaffold was studied in vitro. Biodistribution of the novel positron emission tomography (PET) tracer [ 68 Ga]Ga-DOTA-(PEG) 2 -biotin was evaluated in mice treated by intraportal transplantation of AARs by μPET/computed tomography and ex vivo organ distribution and compared with control mice. Results: AARs had high capability to bind [ 68 Ga]Ga-DOTA-(PEG) 2 -biotin, close to 50% of administrated tracer/μl in vitro (>0.25 MBq/μl). Avidin-tagged human islets could bind on average 2.2% of administered tracer/μl. Specificity (>90%) and retention (>90% after 1 h) were high for both AARs and avidin-tagged islets. Hepatic tracer uptake and retention were increased in mice transplanted with AARs [standardized uptake value (SUV)=2.6] compared to the untreated group (SUV=1.4). In vivo uptake of tracer to AARs was blocked by preadministration of unlabeled biotin. Conclusions: Avidin-tagged islet-like objects can be tracked in hepatic volume after intraportal transplantation by using [ 68 Ga]Ga-DOTA-(PEG) 2 -biotin and PET.

  12. 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

  13. Pancreatic Islet Transplantation

    Science.gov (United States)

    ... in Edmonton, Canada, reported their findings in the New England Journal of Medicine . Their transplant protocol, known as the Edmonton protocol, has since been adapted by transplant centers around the world and continues ... new combination of immunosuppressive medications, also called anti-rejection ...

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

    Science.gov (United States)

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

    2018-03-01

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

  15. Pancreatic islet transplantation. Experimental and clinical aspects

    DEFF Research Database (Denmark)

    Yderstræde, Knud Bonnet

    1987-01-01

    transplantation, future models include microencapsulation and hybrid artificial devices, both of which provide immuno-isolation - thus the ability of allo- as well as xeno-transplantation. The obvious advantage of immuno-isolated islet transplant, as opposed to segmentally engrafted pancreas, is stressed...

  16. Evaluation of alternative sites for islet transplantation in the minipig: interest and limits of the gastric submucosa.

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    Caiazzo, R; Gmyr, V; Hubert, T; Delalleau, N; Lamberts, R; Moerman, E; Kerr-Conte, J; Pattou, F

    2007-10-01

    Since the introduction of glucocorticoid-free immunosuppressive regimens, islet transplantation offers a less invasive alternative to pancreas transplantation. However, complications associated with intraportal islet injection and the progressive functional decline of intrahepatic islets encourage the exploration of alternative sites. Herein we evaluated, in the minipig, the use of the gastric submucosa (GS; group 1, n = 5) for islet transplantation compared with the kidney capsule (KC; group 2, n = 5). Subsequently we attempted to improve the vascularization of the submucosal graft (group 3, n = 5) by the addition of an extracellular matrix rich in growth factors (Matrigel). One month after grafting, we evaluated transplanted islet function in vivo and in vitro. Our study showed better function of islets engrafted in the GS than in the KC (P < .05). Despite the growth factors, Matrigel did not offer a more suitable environment to further improve engraftment (group 3, P < .05). Thus, even if the liver remains the gold standard, the GS represents a potential islet engraftment site, confirming the data obtained in vitro and in the rodent. Offering easy access by endoscopy, this site could constitute an interesting alternative for experimental studies in large mammals and, eventually, for clinical application.

  17. Impact of islet size on pancreatic islet transplantation and potential interventions to improve outcome.

    Science.gov (United States)

    Zorzi, Daria; Phan, Tammy; Sequi, Marco; Lin, Yong; Freeman, Daniel H; Cicalese, Luca; Rastellini, Cristiana

    2015-01-01

    Better results have been recently reported in clinical pancreatic islet transplantation (ITX) due mostly to improved isolation techniques and immunosuppression; however, some limitations still exist. It is known that following transplantation, 30% to 60% of the islets are lost. In our study, we have investigated 1) the role of size as a factor affecting islet engraftment and 2) potential procedural manipulations to increase the number of smaller functional islets that can be transplanted. C57/BL10 mice were used as donors and recipients in a syngeneic islet transplant model. Isolated islets were divided by size (large, >300 μm; medium 150-300 μm; small, <150 μm). Each size was transplanted in chemically induced diabetic mice as full (600 IEQ), suboptimal (400 IEQ), and marginal mass (200 IEQ). Control animals received all size islets. Engraftment was defined as reversal of diabetes by day 7 posttransplantation. When the superiority of smaller islets was observed, strategies of overdigestion and fragmentation were adopted during islet isolation in the attempt to reduce islet size and improve engraftment. Smaller islets were significantly superior in engraftment compared to medium, large, and control (all sizes) groups. This was more evident when marginal mass data were compared. In all masses, success decreased as islet size increased. Once islets were engrafted, functionality was not affected by size. When larger islets were fragmented, a significant decrease in islet functionality was observed. On the contrary, if pancreata were slightly overdigested, although not as successful as small naive islets, an increase in engraftment was observed when compared to the control group. In conclusion, smaller islets are superior in engraftment following islet transplantation. Fragmentation has a deleterious effect on islet engraftment. Islet isolations can be performed by reducing islet size with slight overdigestion, and it can be safely adopted to improve clinical

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

    NARCIS (Netherlands)

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

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

  19. 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.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Long-term insulin independence after islets of Langerhans transplantation is rarely achieved. The aims of this study were to identify the histological and immunological features of islets transplanted in a type 1 diabetic patient who died of a cerebral hemorrhage after >13 years insulin independe......Long-term insulin independence after islets of Langerhans transplantation is rarely achieved. The aims of this study were to identify the histological and immunological features of islets transplanted in a type 1 diabetic patient who died of a cerebral hemorrhage after >13 years insulin...... 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...... microdissection samples, compared to 1/23 for the least matched donor. This case report demonstrates that allogeneic islets can survive over 13 years while maintaining insulin independence. Allogeneic islets had unique morphologic features and implanted in the liver regardless of their size. Finally, our results...

  1. Islet and Stem Cell Encapsulation for Clinical Transplantation

    Science.gov (United States)

    Krishnan, Rahul; Alexander, Michael; Robles, Lourdes; Foster 3rd, Clarence E.; Lakey, Jonathan R.T.

    2014-01-01

    Over the last decade, improvements in islet isolation techniques have made islet transplantation an option for a certain subset of patients with long-standing diabetes. Although islet transplants have shown improved graft function, adequate function beyond the second year has not yet been demonstrated, and patients still require immunosuppression to prevent rejection. Since allogeneic islet transplants have experienced some success, the next step is to improve graft function while eliminating the need for systemic immunosuppressive therapy. Biomaterial encapsulation offers a strategy to avoid the need for toxic immunosuppression while increasing the chances of graft function and survival. Encapsulation entails coating cells or tissue in a semipermeable biocompatible material that allows for the passage of nutrients, oxygen, and hormones while blocking immune cells and regulatory substances from recognizing and destroying the cell, thus avoiding the need for systemic immunosuppressive therapy. Despite advances in encapsulation technology, these developments have not yet been meaningfully translated into clinical islet transplantation, for which several factors are to blame, including graft hypoxia, host inflammatory response, fibrosis, improper choice of biomaterial type, lack of standard guidelines, and post-transplantation device failure. Several new approaches, such as the use of porcine islets, stem cells, development of prevascularized implants, islet nanocoating, and multilayer encapsulation, continue to generate intense scientific interest in this rapidly expanding field. This review provides a comprehensive update on islet and stem cell encapsulation as a treatment modality in type 1 diabetes, including a historical outlook as well as current and future research avenues. PMID:25148368

  2. Three Cases of Alopecia Following Clinical Islet Transplantation

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    Zuk, Dalyce M; Koh, Angela; Imes, Sharleen; Shapiro, AM James; Senior, Peter A

    2010-01-01

    Successful clinical islet allotransplantation requires control of both allo- and auto-immunity by using immunosuppressant drugs which have a number of side effects. The development of the autoimmune condition alopecia areata following successful islet transplantation is therefore unexpected. Three cases of alopecia affecting female islet transplant recipients are described. In all cases, alopecia developed approximately 7 years after initial transplant. All had received daclizumab, sirolimus and tacrolimus with their initial transplants, but all were receiving a combination of tacrolimus and mycophenolate mofetil at the time alopecia developed. Two subjects had received thymoglobulin for a subsequent islet infusion and prior to the onset of alopecia. The progression of alopecia has been halted or reversed in all cases. Tacrolimus has been continued in 2 cases (one as monotherapy) while cyclosporine was used in place of tacrolimus in the third case. These three cases represent a crude incidence of alopecia in islet transplant candidates (pre-transplant) of alopecia might be expected in a proportion of individuals with type 1 diabetes, the risk may be increased after islet transplantation, and may be associated with the use of anti-TNF drugs, lymphodepleting antibodies or higher dose tacrolimus. PMID:21199356

  3. OBSTACLES IN THE APPLICATION OF MICROENCAPSULATION IN ISLET TRANSPLANTATION

    NARCIS (Netherlands)

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

    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

  4. Considerations for successful transplantation of encapsulated pancreatic islets

    NARCIS (Netherlands)

    de Vos, P; Hamel, AF; Tatarkiewicz, K

    Encapsulation of pancreatic islets allows for transplantion in the absence of immunosuppression. The technology is based on the principle that transplanted tissue is protected for the host immune system by an artificial membrane. Encapsulation offers a solution to the shortage of donors in clinical

  5. Caspase inhibitor IDN6556 facilitates marginal mass islet engraftment in a porcine islet autotransplant model.

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    McCall, Michael D; Maciver, Allison M; Kin, Tatsuya; Emamaullee, Juliet; Pawlick, Rena; Edgar, Ryan; Shapiro, A M James

    2012-07-15

    Large numbers of islets are lost in the early phase after clinical islet transplantation, through apoptosis, necrosis, or innate inflammatory injury. We previously demonstrated the efficacy of a series of caspase inhibitors in mouse models on islet engraftment through reduction in early posttransplant apoptosis. We studied IDN6556, a caspase inhibitor with a first-pass effect, in a large animal (pig) intraportal marginal mass islet autotransplant model. Total pancreatectomy and marginal mass islet autotransplantation were carried out in Yucatan miniature swine to explore the effects of IDN6556 on islet engraftment. Pigs were treated with IDN6556 at a dose of 20 mg/kg orally twice daily (n=7) or phosphate-buffered saline control (n=6) orally for 7 days, and blood glucose was monitored for 1 month. Glucose tolerance and acute insulin release were determined at 1 month. There were no differences in islet procurement, isolation, or islet functional parameters between the two groups. Pigs receiving IDN6556 had lower fasting blood glucose level after transplantation and a higher percentage (100% vs. 33.3%) showed fasting blood glucose levels less than 11 mM. This translated into an enhanced metabolic reserve and acute insulin release for pigs in the treatment group. IDN6556 led to enhanced islet engraftment in this large animal islet transplant model. Although this study has limitations including a short interval of study (1 month) and the use of unpurified islets, the results justify early clinical trials of IDN6556 in islet transplantation.

  6. Islet transplantation: lessons learned since the Edmonton breakthrough.

    Science.gov (United States)

    Langer, R M

    2010-06-01

    This work sought to summarize the main issues of the last decade in the field of clinical islet transplantation. Ten years ago in Edmonton, a new protocol initiated for islet transplantation brought a breakthrough to the field. The earlier, rather poor results were in a sharp contrast to the first published results of 100% insulin freedom at 1 year. However, later it became clear that the promising initial results decline with time; at around 5 years, only about 10% of the patients maintain freedom from external insulin. Despite that fact, a milestone was set and intensive research started worldwide. New hopes were raised for patients. Modifications of the original protocol have been implemented to improve clinical results; however, islet transplantation remains an experimental procedure to date.

  7. Novel Fusion Protein Targeting Mitochondrial DNA Improves Pancreatic Islet Functional Potency and Islet Transplantation Outcomes.

    Science.gov (United States)

    Danobeitia, Juan S; Chlebeck, Peter J; Shokolenko, Inna; Ma, Xiaobo; Wilson, Glenn; Fernandez, Luis A

    2017-11-01

    Long-term graft survival is an ongoing challenge in the field of islet transplantation. With the growing demand for transplantable organs, therapies to improve organ quality and reduce the incidence of graft dysfunction are of paramount importance. We evaluated the protective role of a recombinant DNA repair protein targeted to mitochondria (Exscien I-III), as a therapeutic agent using a rodent model of pancreatic islet transplantation. We first investigated the effect of therapy on isolated rat islets cultured with pro-inflammatory cytokines (interleukin-1 β, interferon γ, and tumor necrosis factor α) for 48 h and documented a significant reduction in apoptosis by flow cytometry, improved viability by immunofluorescence, and conserved functional potency in vitro and in vivo in Exscien I-III-treated islets. We then tested the effect of therapy in systemic inflammation using a rat model of donor brain death (BD) sustained for a 6-h period. Donor rats were allocated to 4 groups: (non-BD + vehicle, non-BD + Exscien I-III, BD + vehicle, and BD + Exscien I-III) and treated with Exscien I-III (4 mg/kg) or vehicle 30 min after BD induction. Sham (non-BD)-operated animals receiving either Exscien I-III or vehicle served as controls. Islets purified from BD + Exscien I-III-treated donors showed a significant increase in glucose-stimulated insulin release in vitro when compared to islets from vehicle-treated counterparts. In addition, donor treatment with Exscien I-III attenuated the effects of BD and significantly improved the functional potency of transplanted islets in vivo. Our data indicate that mitochondrially targeted antioxidant therapy is a novel strategy to protect pancreas and islet quality from the deleterious effects of cytokines in culture and during the inflammatory response associated with donation after BD. The potential for rapid translation into clinical practice makes Exscien I-III an attractive therapeutic option for the management of brain

  8. Technique of endoscopic biopsy of islet allografts transplanted into the gastric submucosal space in pigs

    NARCIS (Netherlands)

    T. Fujita (Tetsuji); K.M. McGrath (Kevin); R. Bottino (Rita); E.M. Dons (Eefje); C. Long (Cassandra); G. Kumar (Goutham); B. Ekser; G.J. Echeverri (Gabriel); A. Hata (Akira); K. Haruma (Ken); D.K.C. Cooper (David); H. Hara (Hidetaka)

    2013-01-01

    textabstractCurrently, islet cells are transplanted into the liver via portal vein infusion. One disadvantage of this approach is that it is not possible to adequately biopsy the islets in the liver to assess for rejection. Islet transplantation (Tx) into the gastric submucosal space (GSMS) can be

  9. Animal Models of Diabetes Mellitus for Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Naoaki Sakata

    2012-01-01

    Full Text Available Due to current improvements in techniques for islet isolation and transplantation and protocols for immunosuppressants, islet transplantation has become an effective treatment for severe diabetes patients. Many diabetic animal models have contributed to such improvements. In this paper, we focus on 3 types of models with different mechanisms for inducing diabetes mellitus (DM: models induced by drugs including streptozotocin (STZ, pancreatomized models, and spontaneous models due to autoimmunity. STZ-induced diabetes is one of the most commonly used experimental diabetic models and is employed using many specimens including rodents, pigs or monkeys. The management of STZ models is well established for islet studies. Pancreatomized models reveal different aspects compared to STZ-induced models in terms of loss of function in the increase and decrease of blood glucose and therefore are useful for evaluating the condition in total pancreatomized patients. Spontaneous models are useful for preclinical studies including the assessment of immunosuppressants because such models involve the same mechanisms as type 1 DM in the clinical setting. In conclusion, islet researchers should select suitable diabetic animal models according to the aim of the study.

  10. Current Status of Immunomodulatory and Cellular Therapies in Preclinical and Clinical Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Preeti Chhabra

    2011-01-01

    Full Text Available Clinical islet transplantation is a -cell replacement strategy that represents a possible definitive intervention for patients with type 1 diabetes, offering substantial benefits in terms of lowering daily insulin requirements and reducing incidences of debilitating hypoglycemic episodes and unawareness. Despite impressive advances in this field, a limiting supply of islets, inadequate means for preventing islet rejection, and the deleterious diabetogenic and nephrotoxic side effects associated with chronic immunosuppressive therapy preclude its wide-spread applicability. Islet transplantation however allows a window of opportunity for attempting various therapeutic manipulations of islets prior to transplantation aimed at achieving superior transplant outcomes. In this paper, we will focus on the current status of various immunosuppressive and cellular therapies that promote graft function and survival in preclinical and clinical islet transplantation with special emphasis on the tolerance-inducing capacity of regulatory T cells as well as the -cells regenerative capacity of stem cells.

  11. Technique of endoscopic biopsy of islet allografts transplanted into the gastric submucosal space in pigs.

    Science.gov (United States)

    Fujita, Minoru; McGrath, Kevin M; Bottino, Rita; Dons, Eefje M; Long, Cassandra; Kumar, Goutham; Ekser, Burcin; Echeverri, Gabriel J; Hata, Jiro; Haruma, Ken; Cooper, David K C; Hara, Hidetaka

    2013-01-01

    Currently, islet cells are transplanted into the liver via portal vein infusion. One disadvantage of this approach is that it is not possible to adequately biopsy the islets in the liver to assess for rejection. Islet transplantation (Tx) into the gastric submucosal space (GSMS) can be performed endoscopically and has the potential advantage of histological evaluation by endoscopic biopsy. The aim of this study was to determine whether a representative allograft sample could be obtained endoscopically. We performed islet Tx into the GSMS in nonimmunosuppressed pigs using simple endoscopic submucosal injection. Islets were transplanted at four sites. Endoscopic ultrasonography and biopsy of the transplanted islets at two sites by modified endoscopic submucosal dissection were carried out successfully in all pigs 5 days after islet Tx. Tissue obtained at both biopsy and necropsy (including full-thickness sections of the gastric wall around the sites of the remaining islets and biopsies) were examined by histology and immunohistochemistry to confirm the presence of the islet grafts and any features of rejection. Representative allograft sampling was successfully obtained from all biopsy sites. All biopsies included islets with insulin-positive staining. There was significant CD3(+) and CD68(+) cell infiltration in the islet masses obtained at biopsy and from sections taken at necropsy, with similar histopathological features. Endoscopic biopsy of islet allografts in the GSMS is feasible, provides accurate histopathological data, and would provide a significant advance if translated into clinical practice.

  12. 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.

  13. Effects of pancreas transplantation on late complications of diabetes and metabolic effects of pancreas and islet transplantation.

    Science.gov (United States)

    Caldara, R; La Rocca, E; Maffi, P; Secchi, A

    1999-01-01

    Pancreas transplantation has become an accepted therapeutic approach to treat insulin-dependent diabetes mellitus, successfully restoring normoglycemia. In contrast, islet transplantation is still in the experimental phase, only a few operations having being performed world-wide. The aim of this review is to analyze the effects of pancreas transplantation on the late complications of diabetes and to report the endocrino-metabolic effects of pancreas and islet transplantation.

  14. Nonhuman Primate Models of Type 1 Diabetes Mellitus for Islet Transplantation

    Directory of Open Access Journals (Sweden)

    Haitao Zhu

    2014-01-01

    Full Text Available Islet transplantation is an attractive treatment of type 1 diabetes mellitus (T1DM. Animal models of diabetes mellitus (DM contribute a lot to the experimental studies of islet transplantation and to evaluations of isolated islet grafts for future clinical applications. Diabetic nonhuman primates (NHPs represent the suitable models of DMs to better evaluate the effectiveness of islet transplantation, to assess new strategies for controlling blood glucose (BG, relieving immune rejection, or prolonging islet survival, and eventually to translate the preclinical data into tangible clinical practice. This review introduces some NHP models of DM, clarifies why and how the models should be used, and elucidates the usefulness and limitations of the models in islet transplantation.

  15. Isolation, transplantation, and functional studies of adult porcine islets of Langerhans

    DEFF Research Database (Denmark)

    Nielsen, Thomas Buschmann; Yderstræde, Knud Bonnet; Beck-Nielsen, Henning

    2002-01-01

    Transplantation of islets of Langerhans is a possible treatment for type-I diabetes mellitus. However, there is a shortage of donors for such transplantations and the pig may be an alternative source of donor organs. The aims of the study reported here were to establish a method for adult porcine...... following transplantation. In conclusion, it is possible to isolate viable islets from adult pigs, using a semiautomatic set-up. With batch-to-batch variation, the islets are able to revert diabetes mellitus when transplanted to diabetic nude mice....

  16. Chronically decreased oxygen tension in rat pancreatic islets transplanted under the kidney capsule.

    Science.gov (United States)

    Carlsson, P O; Palm, F; Andersson, A; Liss, P

    2000-03-15

    A factor of potential importance in the failure of islet grafts is poor or inadequate engraftment of the islets in the implantation organ. This study measured the oxygen tension and blood perfusion in 1-, 2-, and 9-month-old islet grafts. The partial pressure of oxygen was measured in pancreatic islets transplanted beneath the renal capsule of diabetic and nondiabetic recipient rats with a modified Clark electrode (outer tip diameter 2-6 microm). The size of the graft (250 islets) was by purpose not large enough to cure the diabetic recipients. The oxygen tension in islets within the pancreas was also recorded. Blood perfusion was measured with the laser-Doppler technique. Within native pancreatic islets, the partial pressure of oxygen was approximately 40 mm Hg (n=8). In islets transplanted to nondiabetic animals, the oxygen tension was approximately 6-7 mm Hg 1, 2, and 9 months posttransplantation. No differences could be seen between the different time points after transplantation. In the diabetic recipients, an even more pronounced decrease in graft tissue oxygen tension was recorded. The mean oxygen tension in the superficial renal cortex surrounding the implanted islets was similar in all groups (approximately 15 mm Hg). Intravenous administration of glucose (0.1 gxkg(-1)x min(-1)) did not affect the oxygen tension in any of the investigated tissues. The islet graft blood flow was similar in all groups, measuring approximately 50% of the blood flow in the kidney cortex. The oxygen tension in islets implanted beneath the kidney capsule is markedly lower than in native islets up to 9 months after transplantation. Moreover, persistent hyperglycemia in the recipient causes an even further decrease in graft oxygen tension, despite similar blood perfusion. To what extent this may contribute to islet graft failure remains to be determined.

  17. Resveratrol fails to improve marginal mass engraftment of transplanted islets of Langerhans in mice.

    Science.gov (United States)

    McCall, Michael D; Pawlick, Rena; Shapiro, A M James

    2011-01-01

    One limitation of current islet transplantation protocols is the loss of up to 70% of the transplanted islet mass. Inflammatory events play a major role in islet loss including the cytokines TNFα and IL-1. Resveratrol, a compound with anti-inflammatory and anti-oxidant properties, has the potential to mitigate islet loss. Using a syngeneic marginal  after mouse islet transplantation model we tested the ability of resveratrol to enhance islet engraftment. We failed to show a difference in diabetes reversal between mice treated with vehicle and those treated with either 10 mg/kg (47.1% for resveratrol vs. 35.3% for control) or 50 mg/kg (20% for resveratrol vs. 22.2% for control) of resveratrol daily for three weeks. In addition, at one month there was no difference in glucose tolerance or graft survival (10 mg/kg: 552.6 ng/ml resveratrol group vs. 576.6 ng/ml control group; 50 mg/kg: 463 ng/ml resveratrol group vs. 444.1 ng/ml control group). In summary, over a wide range of doses, resveratrol did not exert a benefit on mouse islet engraftment. Further studies should be conducted with human islets before deeming resveratrol ineffective in islet engraftment and survival.

  18. A Retrievable, Efficacious Polymeric Scaffold for Subcutaneous Transplantation of Rat Pancreatic Islets

    NARCIS (Netherlands)

    Smink, Alexandra M; Hertsig, Don T; Schwab, Leendert; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; de Haan, Bart J; de Vos, Paul

    2016-01-01

    OBJECTIVE: We aim on developing a polymeric ectopic scaffold in a readily accessible site under the skin. SUMMARY BACKGROUND DATA: The liver as transplantation site for pancreatic islets is associated with significant loss of islets. Several extrahepatic sites were tested in experimental animals,

  19. A Retrievable, Efficacious Polymeric Scaffold for Subcutaneous Transplantation of Rat Pancreatic Islets

    NARCIS (Netherlands)

    Smink, Alexandra M; Hertsig, Don T; Schwab, Leendert; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; de Haan, Bart J; de Vos, Paul

    OBJECTIVE: We aim on developing a polymeric ectopic scaffold in a readily accessible site under the skin. SUMMARY BACKGROUND DATA: The liver as transplantation site for pancreatic islets is associated with significant loss of islets. Several extrahepatic sites were tested in experimental animals,

  20. Selection of polymers for application in scaffolds applicable for human pancreatic islet transplantation

    NARCIS (Netherlands)

    Smink, Alexandra M; de Haan, Bart J; Paredes-Juarez, Genaro A; Wolters, Anouk H G; Kuipers, Jeroen; Giepmans, Ben N G; Schwab, Leendert; Engelse, Marten A; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; de Vos, Paul

    2016-01-01

    The liver is currently the site for transplantation of islets in humans. This is not optimal for islets, but alternative sites in humans are not available. Polymeric scaffolds in surgically accessible areas are a solution. As human donors are rare, the polymers should not interfere with functional

  1. Posttransplant Lymphoproliferative Disorder After Clinical Islet Transplantation: Report of the First Two Cases.

    Science.gov (United States)

    Peters, A; Olateju, T; Deschenes, J; Shankarnarayan, S H; Chua, N; Shapiro, A M J; Senior, P

    2017-09-01

    We report the first two cases of posttransplant lymphoproliferative disorder (PTLD) in recipients of islet transplants worldwide. First, a 44-year-old recipient of three islet infusions developed PTLD 80 months after his initial transplantation, presenting with abdominal pain and diffuse terminal ileum thickening on imaging. He was treated with surgical excision, reduction of immunosuppression, and rituximab. Seven months later, he developed central nervous system PTLD, presenting with vertigo and diplopia; immunosuppression was discontinued, resulting in graft loss, and he was given high-dose methotrexate and underwent consolidative autologous stem cell transplantation. He remains in remission 37 months after the initial diagnosis. Second, a 58-year-old female recipient of two islet infusions developed PTLD 24 months after initial islet infusion, presenting with pancytopenia secondary to extensive bone marrow involvement. Immunosuppression was discontinued, resulting in graft loss, and she received rituximab and chemotherapy, achieving complete remission. Both patients were monomorphic B cell PTLD subtype by histology and negative for Epstein-Barr virus in tissue or blood. These cases document the first occurrences of this rare complication in islet transplantation, likely secondary to prolonged, intensive immunosuppression, and highlight the varying clinical manifestations of PTLD. Further studies are needed to determine incidence rate and risk factors in islet transplantation. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  2. Improving the use of donor organs in pancreas and islet of Langerhans transplantation

    NARCIS (Netherlands)

    Hilling, Denise Eline

    2012-01-01

    Pancreas transplantation and islet of Langerhans transplantation are potential solutions to treat patients with type 1 diabetes. However, pancreas grafts are scarce and there is a shortage of donor pancreata relative to the number of patients needing a transplant. The aim of this thesis was to

  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. Cell loss during pseudoislet formation hampers profound improvements in islet lentiviral transduction efficacy for transplantation purposes.

    Science.gov (United States)

    Callewaert, H; Gysemans, C; Cardozo, A K; Elsner, M; Tiedge, M; Eizirik, D L; Mathieu, C

    2007-01-01

    Islet transplantation is a promising treatment in type 1 diabetes, but the need for chronic immunosuppression is a major hurdle to broad applicability. Ex vivo introduction of agents by lentiviral vectors-improving beta-cell resistance against immune attack-is an attractive path to pursue. The aim of this study was to investigate whether dissociation of islets to single cells prior to viral infection and reaggregation before transplantation would improve viral transduction efficacy without cytotoxicity. This procedure improved transduction efficacy with a LV-pWPT-CMV-EGFP construct from 11.2 +/- 4.1% at MOI 50 in whole islets to 80.0 +/- 2.8% at MOI 5. Viability (as measured by Hoechst/PI) and functionality (as measured by glucose challenge) remained high. After transplantation, the transfected pseudoislet aggregates remained EGFP positive for more than 90 days and the expression of EGFP colocalized primarily with the insulin-positive beta-cells. No increased vulnerability to immune attack was observed in vitro or in vivo. These data demonstrate that dispersion of islets prior to lentiviral transfection and reaggregation prior to transplantation is a highly efficient way to introduce genes of interest into islets for transplantation purposes in vitro and in vivo, but the amount of beta-cells needed for normalization of glycemia was more than eightfold higher when using dispersed cell aggregates versus unmanipulated islets. The high price to pay to reach stable and strong transgene expression in islet cells is certainly an important cell loss.

  5. A Retrievable, Efficacious Polymeric Scaffold for Subcutaneous Transplantation of Rat Pancreatic Islets.

    Science.gov (United States)

    Smink, Alexandra M; Hertsig, Don T; Schwab, Leendert; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; de Haan, Bart J; de Vos, Paul

    2017-07-01

    We aim on developing a polymeric ectopic scaffold in a readily accessible site under the skin. The liver as transplantation site for pancreatic islets is associated with significant loss of islets. Several extrahepatic sites were tested in experimental animals, but many have practical limitations in the clinical setting and do not have the benefit of easy accessibility. Functional survival of rat islets was tested during 7 days of culture in the presence of poly(D,L-lactide-co-ε-caprolactone) (PDLLCL), poly(ethylene oxide terephthalate)/polybutylene terephthalate (PEOT/PBT) block copolymer, and polysulfone. Tissue responses were studied in vivo after subcutaneous implantation in rats. Culture on PEOT/PBT and polysulfone profoundly disturbed function of islets, and induced severe tissue responses in vivo. Modification of their hydrophilicity did not change the suitability of the polymers. PDLLCL was the only polymer that promoted functional survival of rat islets in vitro and was associated with minor tissue reactions after 28 days. Rat islets were transplanted in the PDLLCL scaffold in a diabetic rat model. Before islet seeding, the scaffold was allowed to engraft for 28 days to allow the tissue response to dampen and to allow blood vessel growth into the device. Islet transplantation into the scaffold resulted in normoglycemia within 3 days and for the duration of the study period of 16 weeks. In conclusion, we found that some polymers such as PEOT/PBT and polysulfone interfere with islet function. PDLLCL is a suitable polymer to create an artificial islet transplantation site under the skin and supports islet survival.

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

    Directory of Open Access Journals (Sweden)

    Tatum JA

    2017-02-01

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

  7. Antigen-Encoding Bone Marrow Terminates Islet-Directed Memory CD8+ T-Cell Responses to Alleviate Islet Transplant Rejection

    DEFF Research Database (Denmark)

    Coleman, Miranda; Jessup, Claire F.; Bridge, Jennifer A.

    2016-01-01

    Islet-specific memory T cells arise early in type 1 diabetes (T1D), persist for long periods, perpetuate disease, and are rapidly reactivated by islet transplantation. As memory T cells are poorly controlled by “conventional” therapies, memory T cell–mediated attack is a substantial challenge in ...... responses, and this can alleviate destruction of antigen-expressing islets. This addresses a key challenge facing islet transplantation and, importantly, the clinical application of personalized β-cell replacement therapies using patient-derived stem cells.......Islet-specific memory T cells arise early in type 1 diabetes (T1D), persist for long periods, perpetuate disease, and are rapidly reactivated by islet transplantation. As memory T cells are poorly controlled by “conventional” therapies, memory T cell–mediated attack is a substantial challenge...... in islet transplantation, and this will extend to application of personalized approaches using stem cell–derived replacement β-cells. New approaches are required to limit memory autoimmune attack of transplanted islets or replacement β-cells. Here, we show that transfer of bone marrow encoding cognate...

  8. Selection of polymers for application in scaffolds applicable for human pancreatic islet transplantation.

    Science.gov (United States)

    Smink, Alexandra M; de Haan, Bart J; Paredes-Juarez, Genaro A; Wolters, Anouk H G; Kuipers, Jeroen; Giepmans, Ben N G; Schwab, Leendert; Engelse, Marten A; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; de Vos, Paul

    2016-05-13

    The liver is currently the site for transplantation of islets in humans. This is not optimal for islets, but alternative sites in humans are not available. Polymeric scaffolds in surgically accessible areas are a solution. As human donors are rare, the polymers should not interfere with functional survival of human-islets. We applied a novel platform to test the adequacy of polymers for application in scaffolds for human-islet transplantation. Viability, functionality, and immune parameters were included to test poly(D,L-lactide-co-ε-caprolactone) (PDLLCL), poly(ethylene oxide terephthalate)/polybutylene terephthalate (PEOT/PBT) block copolymer, and polysulfone. The type of polymer influenced the functional survival of human islets. In islets cultured on PDLLCL the glucagon-producing α-cells and insulin-producing β-cells contained more hormone granules than in islets in contact with PEOT/PBT or polysulfone. This was studied with ultrastructural analysis by electron microscopy (nanotomy) during 7 d of culture. PDLLCL was also associated with statistically significant lower release of double-stranded DNA (dsDNA, a so called danger-associate molecular pattern (DAMP)) from islets on PDLLCL when compared to the other polymers. DAMPs support undesired immune responses. Hydrophilicity of the polymers did not influence dsDNA release. Islets on PDLLCL also showed less cellular outgrowth. These outgrowing cells were mainly fibroblast and some β-cells undergoing epithelial to mesenchymal cell transition. None of the polymers influenced the glucose-stimulated insulin secretion. As PDLLCL was associated with less release of DAMPs, it is a promising candidate for creating a scaffold for human islets. Our study demonstrates that for sensitive, rare cadaveric donor tissue such as pancreatic islets it might be necessary to first select materials that do not influence functionality before proposing the biomaterial for in vivo application. Our presented platform may facilitate

  9. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Arne Andersson

    2008-01-01

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  13. Knowledge and Demand for Information about Islet Transplantation in Patients with Type 1 Diabetes

    Directory of Open Access Journals (Sweden)

    Yuko Yamamoto

    2011-01-01

    Full Text Available This cross-sectional study based on self-administrated questionnaire was conducted to investigate knowledge, related factors, and sources of information regarding islet transplantation in patients with type 1 diabetes in Japan. Among 137 patients who provided valid responses, 67 (48.9% knew about islet transplantation. Their main source of information was newspapers or magazines (56.7% and television or radio (46.3%. However, 85.8% of patients preferred the attending physician as their source of information. Although more than half of the patients were correctly aware of issues related to islet transplantation, the following specific issues for islet transplantation were not understood or considered, and there was little knowledge of them: need for immunosuppressants, lifestyle and dietary adaptations, fewer bodily burdens, and complications. The experience of hypoglycaemia, a high level of academic background, frequent self-monitoring of blood glucose, and the use of continuous subcutaneous insulin infusion were related to higher knowledge about islet transplantation.

  14. Factors Influencing Quantification of in Vivo Bioluminescence Imaging: Application to Assessment of Pancreatic Islet Transplants

    Directory of Open Access Journals (Sweden)

    John Virostko

    2004-10-01

    Full Text Available The aim of this study is to determine and characterize factors influencing in vivo bioluminescence imaging (BLI and apply them to the specific application of imaging transplanted pancreatic islets. Noninvasive quantitative assessment of transplanted pancreatic islets poses a formidable challenge. Murine pancreatic islets expressing firefly luciferase were transplanted under the renal capsule or into the portal vein of nonobese diabetic–severe combined immunodeficiency mice and the bioluminescence was quantified with a cooled charge coupled device camera and digital photon image analysis. The important, but often neglected, effects of wound healing, mouse positioning, and transplantation site on bioluminescence measurements were investigated by imaging a constant emission, isotropic light-emitting bead (λ = 600 implanted at the renal or hepatic site. The renal beads emitted nearly four times more light than hepatic beads with a smaller spot size, indicating that light absorption and scatter are greatly influenced by the transplant site and must be accounted for in BLI measurements. Detected luminescence decreased with increasing angle between the mouse surface normal and optical axis. By defining imaging parameters such as postsurgical effects, animal positioning, and light attenuation as a function of transplant site, this study develops BLI as a useful imaging modality for quantitative assessment of islets post-transplantation.

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

    Directory of Open Access Journals (Sweden)

    Emily Sims

    2012-01-01

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

  16. A Metabolomic Approach (1H HRMAS NMR Spectroscopy) Supported by Histology to Study Early Post-transplantation Responses in Islet-transplanted Livers

    Science.gov (United States)

    Vivot, Kevin; Benahmed, Malika A.; Seyfritz, Elodie; Bietiger, William; Elbayed, Karim; Ruhland, Elisa; Langlois, Allan; Maillard, Elisa; Pinget, Michel; Jeandidier, Nathalie; Gies, Jean-Pierre; Namer, Izzie-Jacques; Sigrist, Séverine; Reix, Nathalie

    2016-01-01

    Intrahepatic transplantation of islets requires a lot of islets because more than 50% of the graft is lost during the 24 hours following transplantation. We analyzed, in a rat model, early post-transplantation inflammation using systemic inflammatory markers, or directly in islet-transplanted livers by immunohistochemistry. 1H HRMAS NMR was employed to investigate metabolic responses associated with the transplantation. Inflammatory markers (Interleukin-6, α2-macroglobulin) are not suitable to follow islet reactions as they are not islet specific. To study islet specific inflammatory events, immunohistochemistry was performed on sections of islet transplanted livers for thrombin (indicator of the instant blood-mediated inflammatory reaction (IBMIR)) and granulocytes and macrophages. We observed a specific correlation between IBMIR and granulocyte and macrophage infiltration after 12 h. In parallel, we identified a metabolic response associated with transplantation: after 12 h, glucose, alanine, aspartate, glutamate and glutathione were significantly increased. An increase of glucose is a marker of tissue degradation, and could be explained by immune cell infiltration. Alanine, aspartate and glutamate are inter-connected in a common metabolic pathway known to be activated during hypoxia. An increase of glutathione revealed the presence of antioxidant protection. In this study, IBMIR visualization combined with 1H HRMAS NMR facilitated the characterization of cellular and molecular pathways recruited following islet transplantation. PMID:27766032

  17. Post-transplant processing of superparamagnetic iron nanoparticles used for islet labeling and MR detection

    Czech Academy of Sciences Publication Activity Database

    Zacharovová, K.; Berková, Z.; Herynek, V.; Girman, P.; Koblas, T.; Pektorová, L.; Mindlová, M.; Vávrová, E.; Vancová, Marie; Nebesářová, Jana; Dovolilová, E.; Bobek, V.; Saudek, F.

    2009-01-01

    Roč. 15, č. 5 (2009), s. 425-426 ISSN 0908-665X. [Joint Meeting of the International Pancreas and Islet Transplant Association / International Xenotransplantation Association. 12.10.2009-16.10.2009, Venice ] Institutional research plan: CEZ:AV0Z60220518 Keywords : nanoparticles * ferucarbotran Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  18. Anticarbohydrate Antibody Repertoires in Patients Transplanted with Fetal Pig Islets Revealed by Glycan Arrays

    DEFF Research Database (Denmark)

    Blixt, Klas Ola; Kumagai-Braesch, A.; Tibell, A.

    2009-01-01

    Ten patients with type I diabetes were transplanted with porcine fetal islet-like cell clusters (ICC) between 1990 and 1993. A significant rise in the anti-a-Gal antibody titers was seen posttransplant, but also non-a-Gal-specific antibodies were detected in some patients. We have reanalyzed...

  19. Characterization of islet cells during development and after transplantation

    NARCIS (Netherlands)

    van Gurp, Léon

    2017-01-01

    Diabetes Mellitus is a disease in which patients are not able to maintain blood glucose levels. This is caused by dysfunction or destruction of the beta cells in the islets of Langerhans, located in the pancreas. Beta cells are responsible for the production of insulin, a hormone that decreases the

  20. In Vitro and In Vivo Investigation of the Angiogenic Effects of Liraglutide during Islet Transplantation.

    Directory of Open Access Journals (Sweden)

    Allan Langlois

    Full Text Available This study investigated the angiogenic properties of liraglutide in vitro and in vivo and the mechanisms involved, with a focus on Hypoxia Inducible Factor-1α (HIF-1α and mammalian target of rapamycin (mTOR.Rat pancreatic islets were incubated in vitro with 10 μmol/L of liraglutide (Lira for 12, 24 and 48 h. Islet viability was studied by fluorescein diacetate/propidium iodide staining and their function was assessed by glucose stimulation. The angiogenic effect of liraglutide was determined in vitro by the measure of vascular endothelial growth factor (VEGF secretion using enzyme-linked immunosorbent assay and by the evaluation of VEGF and platelet-derived growth factor-α (PDGFα expression with quantitative polymerase chain reaction technic. Then, in vitro and in vivo, angiogenic property of Lira was evaluated using immunofluorescence staining targeting the cluster of differentiation 31 (CD31. To understand angiogenic mechanisms involved by Lira, HIF-1α and mTOR activation were studied using western blotting. In vivo, islets (1000/kg body-weight were transplanted into diabetic (streptozotocin Lewis rats. Metabolic control was assessed for 1 month by measuring body-weight gain and fasting blood glucose.Islet viability and function were respectively preserved and enhanced (p<0.05 with Lira, versus control. Lira increased CD31-positive cells, expression of VEGF and PDGFα (p<0.05 after 24 h in culture. Increased VEGF secretion versus control was also observed at 48 h (p<0.05. Moreover, Lira activated mTOR (p<0.05 signalling pathway. In vivo, Lira improved vascular density (p<0.01, body-weight gain (p<0.01 and reduced fasting blood glucose in transplanted rats (p<0.001.The beneficial effects of liraglutide on islets appeared to be linked to its angiogenic properties. These findings indicated that glucagon-like peptide-1 analogues could be used to improve transplanted islet revascularisation.

  1. Bibliometric analysis of the top-cited articles on islet transplantation.

    Science.gov (United States)

    Pu, Qiang-Hong; Lyu, Qiu-Ju; Liu, Huan; Fan, Kai-Hua

    2017-11-01

    To identify and characterize the top-cited articles in the field of islet transplantation. We used the Science Citation Index Expanded database to identify the most frequently cited articles published after 1900. Articles were evaluated using the following characteristics: citation number, publication year, study design, references, country and institution of origin, authorship, and journal. Keyword analysis and citation networks were used to analyze research trends. The most frequently cited articles received between 146 and 2988 citations; the median was 291. All of the most frequently cited articles were published between 1972 and 2012, and 85 articles were published after 1990. The most popular study design involved basic science (75 articles). The leading countries were the United States (US) and Canada, and the leading institutions were the University of Alberta, Canada, and the University of Minnesota, in the US. Journals specializing in diabetes or transplantation published more than half of the articles (n = 53, 52%), with the journal Diabetes publishing the largest number (n = 30). No association was found between a journal's impact factor and the number of top-cited articles it published. There was no correlation between the number of citations and the number of years since publication, authors, participating institutions, or countries involved. Top-cited articles focused on 2 themes: the use of antirejection immunotherapy or biocompatible encapsulations to prolong graft survival, and assessments of the efficacy of islet transplants, in particular, islet allografts. Our study can help researchers to identify and decipher the characteristics of top-cited articles in the field of islet transplantation. Just as clinically successful allografts are carried out using the Edmonton protocol, autografts and xenografts should be similarly strengthened to solve problems relating to immune rejection and islet sources, respectively.

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

    NARCIS (Netherlands)

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

    1997-01-01

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

  3. Diabetes mellitus in the BB/W rat. Insulitis in pancreatic islet grafts after transplantation in diabetic recipients.

    OpenAIRE

    Weringer, E. J.; Like, A. A.

    1986-01-01

    Spontaneous diabetes mellitus in the BioBreeding/Worcester (BB/W) rat is preceded by lymphocytic insulitis which destroys pancreatic beta cells. Cultured major histocompatibility complex identical pancreatic islets and adrenal cortex derived from diabetes-resistant BB/W donors were transplanted into diabetic recipients with hyperglycemia of variable duration. Islet grafts were the targets of BB/W immune attack and revealed lymphocytic insulitis after transplantation into diabetic recipients e...

  4. Transplantation of islet cells across major histocompatibility barriers after total lymphoid irradiation and infusion of allogeneic bone marrow cells

    International Nuclear Information System (INIS)

    Britt, L.D.; Scharp, D.W.; Lacy, P.E.; Slavin, S.

    1982-01-01

    Diabetic Lewis rats (AgB1/L) were evaluated as recipients of allogeneic Wistar-Furth (AgB2/2) isolated adult islets without the use of standard recipient immunosuppression. One group was treated with fractionated total lymphoid irradiation (TLI) and Wistar-Furth bone marrow cell reconstitution to proven chimerism prior to islet transplantation. This group returned to a prediabetic state following Wistar-Furth islet transplantation without any evidence of rejection for 100 days posttransplant. A second group of Lewis rats received only TLI without bone marrow treatment. They gave a varying result following islet transplantation with one recipient showing evidence of prolonged islet survival. A third chimeric control group did not receive isolated islets and did not alter their diabetic state. A fourth group was not given TLI nor donor bone marrow cells and uniformly rejected their allogeneic islets by 7 days. Thus, allogeneic adult islets will survive across major rat histocompatibility barriers using TLI and donor bone marrow chimerism as the only form of immunosuppression

  5. Effects of fluid dynamic stress on fracturing of cell-aggregated tissue during purification for islets of Langerhans transplantation

    International Nuclear Information System (INIS)

    Shintaku, H; Kawano, S; Okitsu, T; Matsumoto, S; Suzuki, T; Kanno, I; Kotera, H

    2008-01-01

    Among clinical treatments for type 1 diabetes mellitus, the transplantation of islets of Langerhans to the portal vein of the hepar is a commonly used treatment for glucose homeostasis. Islet purification using the density gradient of a solution in a centrifuge separator is required for safety and efficiency. In the purification, the number of tissues to be transplanted is reduced by removing the acinar tissue and gathering the islet from the digest of pancreas. However, the mechanical effects on the fracture of islets in the centrifuge due to fluid dynamic stress are a serious problem in the purification process. In this study, a preliminary experiment using a cylindrical rotating viscometer with a simple geometry is conducted in order to systematically clarify the effect of fluid dynamic stress on the fracture of islets. The effects of fluid dynamic stress on the islet configuration is quantitatively measured for various flow conditions, and a predictive fracture model is developed based on the experimental results. Furthermore, in the practical purification process in the COBE (Gambro BCT), which is widely used in clinical applications, we perform a numerical analysis of the fluid dynamic stress based on Navier-Stokes equations to estimate the stress conditions for islets. Using the fracture model and numerical analysis, the islet fracture characteristics using the COBE are successfully investigated. The results obtained in this study provide crucial information for the purification of islets by centrifuge in practical and clinical applications

  6. The Efficacy of a Prevascularized, Retrievable Poly(D,L,-lactide-co-epsilon-caprolactone) Subcutaneous Scaffold as Transplantation Site for Pancreatic Islets

    NARCIS (Netherlands)

    Smink, Alexandra M; Li, Shiri; Hertsig, Don T; de Haan, Bart J; Schwab, Leendert; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; Lakey, Jonathan R T; de Vos, Paul

    Background. The liver as transplantation site for human pancreatic islets is a harsh microenvironment for islets and it lacks the ability to retrieve the graft. A retrievable, extrahepatic transplantation site that mimics the pancreatic environment is desired. Ideally, this transplantation site

  7. Processing of superparamagnetic iron contrast agent ferucarbotran in transplanted pancreatic islets

    Czech Academy of Sciences Publication Activity Database

    Zacharovová, K.; Berková, Z.; Jirák, D.; Herynek, V.; Vancová, Marie; Dovolilová, E.; Saudek, F.

    2012-01-01

    Roč. 7, č. 6 (2012), s. 485-493 ISSN 1555-4309 Institutional research plan: CEZ:AV0Z60220518 Keywords : magnetic resonance imaging * pancreatic islets * transplantation * superparamagnetic iron oxide nanoparticles * ferucarbotran * β cells * diabetes * immunohistochemistry * transmission electron microscopy Subject RIV: CE - Biochemistry Impact factor: 2.872, year: 2012 http://onlinelibrary.wiley.com/doi/10.1002/cmmi.1477/full

  8. Exenatide Pretreatment Improved Graft Function in Nonhuman Primate Islet Recipients Compared to Treatment after Transplant Only

    Directory of Open Access Journals (Sweden)

    Jill L. Buss

    2012-01-01

    Full Text Available The GLP-1 receptor agonist, exenatide, has previously been shown to improve insulin secretion, protect beta cells from apoptosis, and promote beta cell regeneration. We propose that pretreatment with exenatide will promote islet graft survival and improve graft function. Pancreatectomized cynomolgus monkeys underwent islet allotransplantation and were treated with exenatide beginning on day 0 or day −2. A third group of animals was treated with an immunosuppressive regimen while a fourth group remained untreated. Fasting blood glucose (FBG was used to evaluate graft function along with intravenous glucose tolerance tests (IVGTTs performed at study endpoint (day 10 for untreated and posttransplant exenatide or day 90 for pretreatment exenatide and immunosuppression. The average FBG for pre-treated animals day 5 following transplant was 52.7±14.8 mg/dl, compared to 154.3±105.5 mg/dl for animals treated only following transplant, 59.4 mg/dl ±12.1 for animals treated with immunosuppression, and 265.5±172.3 mg/dl for untreated animals. IVGTTs performed at study endpoint showed normal glucose and insulin curves in the pre-treated exenatide and immunosuppression groups only, with beta cell function actually improving after transplant in the pre-treated group. We conclude, therefore, that exenatide pre-treatment can successfully maintain islet graft survival in nonhuman primates.

  9. In Vitro and In Vivo Investigation of the Angiogenic Effects of Liraglutide during Islet Transplantation

    Science.gov (United States)

    Langlois, Allan; Mura, Carole; Bietiger, William; Seyfritz, Elodie; Dollinger, Camille; Peronet, Claude; Maillard, Elisa; Pinget, Michel; Jeandidier, Nathalie; Sigrist, Séverine

    2016-01-01

    Introduction This study investigated the angiogenic properties of liraglutide in vitro and in vivo and the mechanisms involved, with a focus on Hypoxia Inducible Factor-1α (HIF-1α) and mammalian target of rapamycin (mTOR). Materials and Methods Rat pancreatic islets were incubated in vitro with 10 μmol/L of liraglutide (Lira) for 12, 24 and 48 h. Islet viability was studied by fluorescein diacetate/propidium iodide staining and their function was assessed by glucose stimulation. The angiogenic effect of liraglutide was determined in vitro by the measure of vascular endothelial growth factor (VEGF) secretion using enzyme-linked immunosorbent assay and by the evaluation of VEGF and platelet-derived growth factor-α (PDGFα) expression with quantitative polymerase chain reaction technic. Then, in vitro and in vivo, angiogenic property of Lira was evaluated using immunofluorescence staining targeting the cluster of differentiation 31 (CD31). To understand angiogenic mechanisms involved by Lira, HIF-1α and mTOR activation were studied using western blotting. In vivo, islets (1000/kg body-weight) were transplanted into diabetic (streptozotocin) Lewis rats. Metabolic control was assessed for 1 month by measuring body-weight gain and fasting blood glucose. Results Islet viability and function were respectively preserved and enhanced (p<0.05) with Lira, versus control. Lira increased CD31-positive cells, expression of VEGF and PDGFα (p<0.05) after 24 h in culture. Increased VEGF secretion versus control was also observed at 48 h (p<0.05). Moreover, Lira activated mTOR (p<0.05) signalling pathway. In vivo, Lira improved vascular density (p<0.01), body-weight gain (p<0.01) and reduced fasting blood glucose in transplanted rats (p<0.001). Conclusion The beneficial effects of liraglutide on islets appeared to be linked to its angiogenic properties. These findings indicated that glucagon-like peptide-1 analogues could be used to improve transplanted islet revascularisation

  10. Pravastatin Improves Glucose Regulation and Biocompatibility of Agarose Encapsulated Porcine Islets following Transplantation into Pancreatectomized Dogs

    Directory of Open Access Journals (Sweden)

    Lawrence S. Gazda

    2014-01-01

    Full Text Available The encapsulation of porcine islets is an attractive methodology for the treatment of Type I diabetes. In the current study, the use of pravastatin as a mild anti-inflammatory agent was investigated in pancreatectomized diabetic canines transplanted with porcine islets encapsulated in agarose-agarose macrobeads and given 80 mg/day of pravastatin (n=3 while control animals did not receive pravastatin (n=3. Control animals reached preimplant insulin requirements on days 18, 19, and 32. Pravastatin-treated animals reached preimplant insulin requirements on days 22, 27, and 50. Two animals from each group received a second macrobead implant: control animals remained insulin-free for 15 and 21 days (AUC = 3003 and 5078 mg/dL/24 hr days 1 to 15 and reached preimplant insulin requirements on days 62 and 131. Pravastatin treated animals remained insulin-free for 21 and 34 days (AUC = 1559 and 1903 mg/dL/24 hr days 1 to 15 and reached preimplant insulin requirements on days 38 and 192. Total incidence (83.3% versus 64.3% and total severity (22.7 versus 18.3 of inflammation on tissue surfaces were higher in the control group at necropsy. These findings support pravastatin therapy in conjunction with the transplantation of encapsulated xenogeneic islets for the treatment of diabetes mellitus.

  11. 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.

  12. Microbial contamination of transplant solutions during pancreatic islet autotransplants is not associated with clinical infection in a pediatric population.

    Science.gov (United States)

    Berger, Megan G; Majumder, Kaustav; Hodges, James S; Bellin, Melena D; Schwarzenberg, Sarah Jane; Gupta, Sameer; Dunn, Ty B; Beilman, Gregory J; Pruett, Timothy L; Freeman, Martin L; Wilhelm, Joshua J; Sutherland, David E R; Chinnakotla, Srinath

    2016-01-01

    Total pancreatectomy and islet autotransplant (TP-IAT) is a potential treatment for children with severe refractory chronic pancreatitis. Cultures from the resected pancreas and final islet preparation are frequently positive for microbes. It is unknown whether positive cultures are associated with adverse outcomes in pediatric patients. We reviewed the medical records of children (n = 86) who underwent TP-IAT from May 2006-March 2015 with emphasis on demographics, previous pancreatic interventions, culture results, islet yield, hospital days, posttransplant islet function, and posttransplant infections. We compared outcomes in patients with positive (n = 57) and negative (n = 29) cultures. Patients with positive cultures had higher rates of previous pancreas surgery (P = 0.007) and endoscopic retrograde cholangiopancreatography (P < 0.0001). Positive cultures were not associated with posttransplant infections (P = 1.00) or prolonged hospital length of stay (P = 0.29). Patients with positive final islet preparation culture showed increased rates of graft failure at 2 years posttransplant (P = 0.041), but not when adjusted for islet mass transplanted (P = 0.39). Positive cultures during pediatric TP-IATs do not increase the risk of posttransplant infections or prolong hospital length of stay. Endocrine function depends on islet mass transplanted. Copyright © 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  13. Effects of Composition of Alginate-Polyethylene Glycol Microcapsules and Transplant Site on Encapsulated Islet Graft Outcomes in Mice.

    Science.gov (United States)

    Villa, Chiara; Manzoli, Vita; Abreu, Maria M; Verheyen, Connor A; Seskin, Michael; Najjar, Mejdi; Molano, R Damaris; Torrente, Yvan; Ricordi, Camillo; Tomei, Alice A

    2017-05-01

    Understanding the effects of capsule composition and transplantation site on graft outcomes of encapsulated islets will aid in the development of more effective strategies for islet transplantation without immunosuppression. Here, we evaluated the effects of transplanting alginate (ALG)-based microcapsules (Micro) in the confined and well-vascularized epididymal fat pad (EFP) site, a model of the human omentum, as opposed to free-floating in the intraperitoneal cavity (IP) in mice. We also examined the effects of reinforcing ALG with polyethylene glycol (PEG). To allow transplantation in the EFP site, we minimized capsule size to 500 ± 17 μm. Unlike ALG, PEG resists osmotic stress, hence we generated hybrid microcapsules by mixing PEG and ALG (MicroMix) or by coating ALG capsules with a 15 ± 2 μm PEG layer (Double). We found improved engraftment of fully allogeneic BALB/c islets in Micro capsules transplanted in the EFP (median reversal time [MRT], 1 day) versus the IP site (MRT, 5 days; P < 0.01) in diabetic C57BL/6 mice and of Micro encapsulated (MRT, 8 days) versus naked (MRT, 36 days; P < 0.01) baboon islets transplanted in the EFP site. Although in vitro viability and functionality of islets within MicroMix and Double capsules were comparable to Micro, addition of PEG to ALG in MicroMix capsules improved engraftment of allogeneic islets in the IP site, but resulted deleterious in the EFP site, probably due to lower biocompatibility. Our results suggest that capsule composition and transplant site affect graft outcomes through their effects on nutrient availability, capsule stability, and biocompatibility.

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

    Science.gov (United States)

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

    2010-01-01

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

  15. Combined Microencapsulated Islet Transplantation and Revascularization of Aortorenal Bypass in a Diabetic Nephropathy Rat Model

    Directory of Open Access Journals (Sweden)

    Yunqiang He

    2016-01-01

    Full Text Available Objective. Revascularization of aortorenal bypass is a preferred technique for renal artery stenosis (RAS in diabetic nephropathy (DN patients. Restenosis of graft vessels also should be considered in patients lacking good control of blood glucose. In this study, we explored a combined strategy to prevent the recurrence of RAS in the DN rat model. Methods. A model of DN was established by intraperitoneal injection of streptozotocin. Rats were divided into 4 groups: SR group, MIT group, Com group, and the untreated group. The levels of blood glucose and urine protein were measured, and changes in renal pathology were observed. The expression of monocyte chemoattractant protein-1 (MCP-1 in graft vessels was assessed by immunohistochemical staining. Histopathological staining was performed to assess the pathological changes of glomeruli and tubules. Results. The levels of urine protein and the expression of MCP-1 in graft vessels were decreased after islet transplantation. The injury of glomerular basement membrane and podocytes was significantly ameliorated. Conclusions. The combined strategy of revascularization and microencapsulated islet transplantation had multiple protective effects on diabetic nephropathy, including preventing atherosclerosis in the graft vessels and alleviating injury to the glomerular filtration barrier. This combined strategy may be helpful for DN patients with RAS.

  16. Recent progress in the use and tracking of transplanted islets as a personalized treatment for type 1 diabetes

    NARCIS (Netherlands)

    Paredes-Juarez, Genaro A; de Vos, Paul; Bulte, Jeff W M

    2017-01-01

    Introduction: Type 1 diabetes mellitus (T1DM) is an autoimmune disease in which the pancreas produces insufficient amounts of insulin. T1DM patients require exogenous sources of insulin to maintain euglycemia. Transplantation of naked or microencapsulated pancreatic islets represents an alternative

  17. Progression of nephropathy after islet of langerhans transplantation in alloxan-induced diabetic rats

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    César Tadeu Spadella

    1997-03-01

    Full Text Available We studied the effects of islet of Langerhans transplantation (IT on the kidney lesions of rats with alloxan-induced diabetes. Forty-five inbred male Lewis rats were randomly assigned to 3 experimental groups: group Gl included 15 non-diabetic control rats (NC, group GIT included 15 alloxan-induced diabetic rats (DC, and group III included 15 alloxan-induced diabetic rats that received pancreatic islet transplantation prepared by nonenzymatic method from normal donor Lewis rats and injected into the portal vein (IT. Each group was further divided into 3 subgroups of 5 rats which were sacrificed at 1, 3, and 6 months of follow-up, respectively. Clinical and laboratorial parameters were recorded in the mentioned periods in the 3 experimental groups. For histology, the kidneys of all rats of each subgroup were studied and 50 glomeruli and 50 tubules of each kidney were analyzed using light microscopy by two different investigators in a double blind study. The results showed progressive glomerular basement membrane thickening (GBMT, mesangial enlargement (ME, and Bowman's capsule thickening (BCT in the 3 experimental groups throughout the follow-up. These alterations were significantly more severe in DC rats at 6 months when compared to NC rats (p < 0.01. However, the degree of GBMT, ME, and BCT observed in DC rats was not statistically different from IT rats at 1, 3, and 6 months. In addition, Armanni-Ebstein lesions of the tubules (AE and tubular lumen protein (PRO observed in DC rats were also observed in IT rats all over the study. These lesions were never present in NC rats. We conclude that IT did not prevent progression of kidney lesions in alloxan-induced diabetic rats within 6 months after transplantation.

  18. Long-term follow-up of patients with type 1 diabetes transplanted with neonatal pig islets.

    Science.gov (United States)

    Valdes-Gonzalez, R; Rodriguez-Ventura, A L; White, D J G; Bracho-Blanchet, E; Castillo, A; Ramírez-González, B; López-Santos, M G; León-Mancilla, B H; Dorantes, L M

    2010-12-01

    Pancreas transplantation is an option to achieve better metabolic control and decrease chronic complications in patients with diabetes. Xenotransplantation becomes an important alternative. In this study, we show the clinical outcome of patients with type 1 diabetes transplanted with neonatal pig islets without immunosuppression. In a longitudinal study of 23 patients with type 1 diabetes, who received porcine islets between 2000 and 2004, we registered demographic and clinical characteristics every 3 months and chronic complications evaluation yearly. Porcine C-peptide was measured in urine samples under basal conditions and after stimulation with l-arginine. More than 50% were female, median current age was 20·8 years, median diabetes duration at transplantation 5·5 years, median current diabetes duration 11 years and median time post-transplantation 5·7 years. Their media of glycosylated haemoglobin reduced significantly after the first transplantation. Insulin doses remain with a reduction greater than 33% in more than 50% of the patients. Before transplantation, 14 of the 21 patients presented mild chronic complications and currently only two patients presented these complications. Porcine C-peptide was present in all urine samples under basal conditions and increased post-stimulation with l-arginine. These patients achieved an excellent metabolic control after the first transplantation. This could explain, as well as the remaining function of transplanted cells, the low frequency of chronic complications compared to patients with similar diabetes duration and age. © 2010 The Authors. Clinical and Experimental Immunology © 2010 British Society for Immunology.

  19. Effect of a new drug releasing system on microencapsulated islet transplantation

    Science.gov (United States)

    Lu, Binjie; Gao, Qingkun; Liu, Rui; Ren, Ming; Wu, Yan; Jiang, Zaixing; Zhou, Yi

    2015-01-01

    Objective: This study aimed to develop a novel release system for grafted islets. Materials and methods: A graphene oxide-FTY720 release system was constructed to test the drug loading and releasing capacity. The recipient rats were divided into four groups as following: Experiment group A (EG A) and B (EG B); Control group A (CG A) and B (CG B). In each group, (2000±100) IEQ microencapsulated islets were implanted into the abdominal cavity of the recipients with oral FTY720, local graphene oxide-FTY720 injection, without immunosuppressants, and with graphene oxide-saturated solution respectively. We detected the immunological data, the blood glucose level, and pericapsular overgrowth to show the transplantation effect. Results: 31% of adsorptive FTY720 was released within 6 h, and 82% of FTY720 was released within 48 h. From day 5 to 8, the amount of PBL in EG B was significantly less than those in EG A (PGraphene oxide-FTY720 complex showed a drug releasing effect. Local application of graphene-FTY720 releasing system could decrease the amount of peripheral blood lymphocytes (PBL) and the percentage of CD3 and CD8 T lymphocytes in blood for longer time than oral drug application. This releasing system could achieve a better blood glucose control. PMID:26722425

  20. Robot-assisted pancreatoduodenectomy with preservation of the vascular supply for autologous islet cell isolation and transplantation: a case report

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    Giulianotti Piero

    2012-03-01

    Full Text Available Abstract Introduction For patients with chronic pancreatitis presenting with medically intractable abdominal pain, surgical intervention may be the only treatment option. However, extensive pancreatic resections are typically performed open and are associated with a substantial amount of postoperative pain, wound complications and long recovery time. Minimally invasive surgery offers an avenue to improve results; however, current limitations of laparoscopic surgery render its application in the setting of chronic pancreatitis technically demanding. Additionally, pancreatic resections are associated with a high incidence of diabetes. Transplantation of islets isolated from the resected pancreas portion offers a way to prevent post-surgical diabetes; however, preservation of the vascular supply during pancreatic resection, which determines islet cell viability, is technically difficult using current laparoscopic approaches. With recent advances in the surgical field, robotic surgery now provides a means to overcome these obstacles to achieve the end goals of pain relief and preserved endocrine function. We present the first report of a novel, minimally invasive robotic approach for resection of the pancreatic head that preserves vascular supply and enables the isolation of a high yield of viable islets for transplantation. Case presentation A 35-year old Caucasian woman presented with intractable chronic abdominal pain secondary to chronic pancreatitis, with a stricture of her main pancreatic duct at the level of the ampulla of Vater and distal dilatation. She was offered a robotic-assisted pylorus-preserving pancreatoduodenectomy and subsequent islet transplantation, to both provide pain relief and preserve insulin-secretory reserves. Conclusion We present a novel, minimally invasive robotic approach for resection of the pancreatic head with complete preservation of the vascular supply, minimal warm ischemia time (less than three minutes and

  1. Syngeneic islet transplantation in prediabetic BB-DP rats--a synchronized model for studying beta-cell destruction during the development of IDDM.

    Science.gov (United States)

    Christensen, U B; Sparre, T; Cooke, A; Andersen, H U; Mandrup-Poulsen, T; Nerup, J

    1998-01-01

    During development of IDDM mononuclear cell infiltration is seen in the islets of Langerhans in both man and rodent models. This process is not synchronized in time and space. To create a synchronized model for investigation of the cellular and molecular events during IDDM development, we isolated and transplanted 200 neonatal BB-DP rat islets under the kidney capsule of 30 day old BB-DP rats. Islet transplantations were also carried out from Wistar Furth (WF) to WF rats, from WF to Wistar Kyoto (WK) rats and from WK to BB-DP rats to compare disease occurrence in an islet syngraft with changes in islet syngrafts or allografts in non-diabetes prone recipients and with changes in islet allografts in diabetes prone recipients, respectively. Pancreata and grafts were harvested at pre-scheduled time points before onset of diabetes and at onset of diabetes, and stained for insulin, MHC class I, MHC class II, alphabeta-TCR, CD4, CD8 or ED1. Diabetes incidence in the syngrafted BB-DP rats was 75% at 78 +/- 5 days of age. The incidence and time of onset of IDDM was unaffected by islet syngrafting. Positive correlations were found between the percentage of infiltrated islets in situ and the number of infiltrating cells in the islet syngraft from the same BB-DP rats (p = 0.003-p IDDM.

  2. 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

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    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

  3. Transplantation of islet allografts and xenografts in totally pancreatectomized diabetic dogs using the hybrid artificial pancreas.

    Science.gov (United States)

    Monaco, A P; Maki, T; Ozato, H; Carretta, M; Sullivan, S J; Borland, K M; Mahoney, M D; Chick, W L; Muller, T E; Wolfrum, J

    1991-01-01

    Previously the authors reported on a Hybrid Artificial Pancreas device that maintained patent vascular anastomoses in normal dogs and, when seeded with allogeneic canine islets, maintained normal fasting blood sugars (FBS) in diabetic pancreatectomized dogs. Eventual failure of these devices was believed to be related to loss of islet viability and/or insufficient islet mass. The current study evaluates the effect of increased islet mass produced by implantation of two islet-seeded devices in pancreatectomized dogs and compares the results with those from dogs that received a single device. Twelve of fifteen dogs receiving single devices showed initial function as determined by elimination or reduction of exogenous insulin requirement; four showed initial function and seven showed extended function (100 to 284 days). Excessive weight loss (more than 20%), despite normal FBS and insulin dependence, required that four animals in this latter group be killed. Devices seeded with xenogeneic islets have met with limited success. One dog that received two bovine islet-seeded devices achieved function for more than 100 days; the remaining bovine-seeded devices (n = 8) functioned for only 3 to 16 days. Porcine islet-seeded devices were assessed by intravenous glucose tolerance tests (IVGTT). Recipients of two devices seeded with allogeneic islets demonstrated improved IVGTT results when compared to those from pancreatectomized dogs and recipients of single devices but were abnormal when compared to intact animals. Histologic examination of device and autopsy material from all failed experiments was performed and showed no mononuclear cell infiltration of the islet chamber or vascular graft material, only a few incidence of device thrombosis, and varying degrees of islet viability as judged by morphologic and immunohistochemical evaluation. The authors believe they have demonstrated progress toward the development and clinical applicability of the Hybrid Artificial Pancreas

  4. Evaluation of a Collagen-Chitosan Hydrogel for Potential Use as a Pro-Angiogenic Site for Islet Transplantation

    Science.gov (United States)

    McBane, Joanne E.; Vulesevic, Branka; Padavan, Donna T.; McEwan, Kimberly A.; Korbutt, Gregory S.; Suuronen, Erik J.

    2013-01-01

    Islet transplantation to treat type 1 diabetes (T1D) has shown varied long-term success, due in part to insufficient blood supply to maintain the islets. In the current study, collagen and collagen:chitosan (10:1) hydrogels, +/- circulating angiogenic cells (CACs), were compared for their ability to produce a pro-angiogenic environment in a streptozotocin-induced mouse model of T1D. Initial characterization showed that collagen-chitosan gels were mechanically stronger than the collagen gels (0.7kPa vs. 0.4kPa elastic modulus, respectively), had more cross-links (9.2 vs. 7.4/µm2), and were degraded more slowly by collagenase. After gelation with CACs, live/dead staining showed greater CAC viability in the collagen-chitosan gels after 18h compared to collagen (79% vs. 69%). In vivo, collagen-chitosan gels, subcutaneously implanted for up to 6 weeks in a T1D mouse, showed increased levels of pro-angiogenic cytokines over time. By 6 weeks, anti-islet cytokine levels were decreased in all matrix formulations ± CACs. The 6-week implants demonstrated increased expression of VCAM-1 in collagen-chitosan implants. Despite this, infiltrating vWF+ and CXCR4+ angiogenic cell numbers were not different between the implant types, which may be due to a delayed and reduced cytokine response in a T1D versus non-diabetic setting. The mechanical, degradation and cytokine data all suggest that the collagen-chitosan gel may be a suitable candidate for use as a pro-angiogenic ectopic islet transplant site. PMID:24204863

  5. Evaluation of a collagen-chitosan hydrogel for potential use as a pro-angiogenic site for islet transplantation.

    Directory of Open Access Journals (Sweden)

    Joanne E McBane

    Full Text Available Islet transplantation to treat type 1 diabetes (T1D has shown varied long-term success, due in part to insufficient blood supply to maintain the islets. In the current study, collagen and collagen:chitosan (10:1 hydrogels, +/- circulating angiogenic cells (CACs, were compared for their ability to produce a pro-angiogenic environment in a streptozotocin-induced mouse model of T1D. Initial characterization showed that collagen-chitosan gels were mechanically stronger than the collagen gels (0.7 kPa vs. 0.4 kPa elastic modulus, respectively, had more cross-links (9.2 vs. 7.4/µm(2, and were degraded more slowly by collagenase. After gelation with CACs, live/dead staining showed greater CAC viability in the collagen-chitosan gels after 18 h compared to collagen (79% vs. 69%. In vivo, collagen-chitosan gels, subcutaneously implanted for up to 6 weeks in a T1D mouse, showed increased levels of pro-angiogenic cytokines over time. By 6 weeks, anti-islet cytokine levels were decreased in all matrix formulations ± CACs. The 6-week implants demonstrated increased expression of VCAM-1 in collagen-chitosan implants. Despite this, infiltrating vWF(+ and CXCR4(+ angiogenic cell numbers were not different between the implant types, which may be due to a delayed and reduced cytokine response in a T1D versus non-diabetic setting. The mechanical, degradation and cytokine data all suggest that the collagen-chitosan gel may be a suitable candidate for use as a pro-angiogenic ectopic islet transplant site.

  6. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    Science.gov (United States)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  7. Transplante isogênico de ilhotas de Langerhans no fígado de ratos: metodologia para separação e purificação das ilhotas de Langerhans Isogenic islet transplantation on the rat liver: Method for isolation and purification of the rat islets

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    Eleazar CHAIB

    2000-01-01

    Full Text Available A maior indicação do transplante de pâncreas ou de ilhotas de Langerhans é o diabetes mellitus do tipo I. O processo deve suprir as necessidades de insulina mantendo os níveis glicêmicos dentro da normalidade. Estudou-se o transplante isogênico de ilhotas de Langerhans no fígado de ratos WAG-RT1u. Com o método de separação e purificação das ilhotas de Langerhans obteve-se 2.834 ± 551,64 ilhotas com pureza de 83 ± 2,45%. O transplante de 2.834 ± 551,64 ilhotas de Langerhans no fígado destes animais, normalizou a glicemia que chegou a 35 mmol/L após indução do diabetes pela estreptozotocina, ficando em 9,62 ± 2,65 mmol/L nos primeiros 10 dias após o enxerto e 7,43 ± 0,27 mmol/L nos dias subseqüentes (P The major indication for pancreas or islet transplantation is diabetes mellitus type I. This process has to supply the insulin necessity keeping glucose under control. We have studied isogenic islet transplantation on the rat (WAG-RT1u liver. The method of isolation and purification of the islets obtained 2.834 ± 551,64 islets with purity of 83 ± 2,45%. Diabetes was induced by streptozotocin and seric glucose prior transplantation was 35 mmol/L. The islet transplantation of 2.834 ± 551,64 islets in the rat liver has normalized glucose test from 9,62 ± 2,65 mmol/L 10 days after transplantation to 7,43 ± 0,27 mmol/L later in the follow-up (P <0,05. The median survival time of the islets was 73 days. In conclusion both the method of isolation and purification of the islets and islet transplantation was effective in the control of the diabetes induced by streptozotocin with median survival time of both islet and rat more than 73 days when rats were sacrificied.

  8. The effects of exendin-4 treatment on graft failure: an animal study using a novel re-vascularized minimal human islet transplant model.

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    Afaf Sahraoui

    Full Text Available Islet transplantation has become a viable clinical treatment, but is still compromised by long-term graft failure. Exendin-4, a glucagon-like peptide 1 receptor agonist, has in clinical studies been shown to improve insulin secretion in islet transplanted patients. However, little is known about the effect of exendin-4 on other metabolic parameters. We therefore aimed to determine what influence exendin-4 would have on revascularized minimal human islet grafts in a state of graft failure in terms of glucose metabolism, body weight, lipid levels and graft survival. Introducing the bilateral, subcapsular islet transplantation model, we first transplanted diabetic mice with a murine graft under the left kidney capsule sufficient to restore normoglycemia. After a convalescent period, we performed a second transplantation under the right kidney capsule with a minimal human islet graft and allowed for a second recovery. We then performed a left-sided nephrectomy, and immediately started treatment with exendin-4 with a low (20μg/kg/day or high (200μg/kg/day dose, or saline subcutaneously twice daily for 15 days. Blood was sampled, blood glucose and body weight monitored. The transplanted human islet grafts were collected at study end point and analyzed. We found that exendin-4 exerts its effect on failing human islet grafts in a bell-shaped dose-response curve. Both doses of exendin-4 equally and significantly reduced blood glucose. Glucagon-like peptide 1 (GLP-1, C-peptide and pro-insulin were conversely increased. In the course of the treatment, body weight and cholesterol levels were not affected. However, immunohistochemistry revealed an increase in beta cell nuclei count and reduced TUNEL staining only in the group treated with a low dose of exendin-4 compared to the high dose and control. Collectively, these results suggest that exendin-4 has a potential rescue effect on failing, revascularized human islets in terms of lowering blood glucose

  9. Comparison of different compressed sensing algorithms for low SNR19F MRI applications-Imaging of transplanted pancreatic islets and cells labeled with perfluorocarbons.

    Science.gov (United States)

    Liang, Sayuan; Dresselaers, Tom; Louchami, Karim; Zhu, Ce; Liu, Yipeng; Himmelreich, Uwe

    2017-11-01

    Transplantation of pancreatic islets is a possible treatment option for patients suffering from Type I diabetes. In vivo imaging of transplanted islets is important for assessment of the transplantation site and islet distribution. Thanks to its high specificity, the absence of intrinsic background signal in tissue and its potential for quantification, 19 F MRI is a promising technique for monitoring the fate of transplanted islets in vivo. In order to overcome the inherent low sensitivity of 19 F MRI, leading to long acquisition times with low signal-to-noise ratio (SNR), compressed sensing (CS) techniques are a valuable option. We have validated and compared different CS algorithms for acceleration of 19 F MRI acquisition in a low SNR regime using pancreatic islets labeled with perfluorocarbons both in vitro and in vivo. Using offline simulation on both in vitro and in vivo low SNR fully sampled 19 F MRI datasets of labeled islets, we have shown that CS is effective in reducing the image acquisition time by a factor of three to four without seriously affecting SNR, regardless of the particular algorithms used in this study, with the exception of CoSaMP. Using CS, signals can be detected that might have been missed by conventional 19 F MRI. Among different algorithms (SPARSEMRI, OMMP, IRWL1, Two-level and CoSAMP), the two-level l 1 method has shown the best performance if computational time is taken into account. We have demonstrated in this study that different existing CS algorithms can be used effectively for low SNR 19 F MRI. An up to fourfold gain in SNR/scan time could be used either to reduce the scan time, which is beneficial for clinical and translational applications, or to increase the number of averages, to potentially detect otherwise undetected signal when compared with conventional 19 F MRI acquisitions. Potential applications in the field of cell therapy have been demonstrated. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Utilization of organs from donors after circulatory death for vascularized pancreas and islet of Langerhans transplantation : recommendations from an expert group

    NARCIS (Netherlands)

    Berney, Thierry; Boffa, Catherine; Augustine, Titus; Badet, Lionel; de Koning, Eelco; Pratschke, Johann; Socci, Carlo; Friend, Peter

    2015-01-01

    Donation after circulatory death (DCD) donors are increasingly being used as a source of pancreas allografts for vascularized organ and islet transplantation. We provide practice guidelines aiming to increase DCD pancreas utilization. We review risk assessment and donor selection criteria. We report

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

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    Kuo Ching Chao

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

  12. Correlation between insulin requirements and anti-galactose antibodies in patients with type 1 diabetes transplanted with neonatal pig islets.

    Science.gov (United States)

    Esquivel-Pérez, R; Rodriguez-Ventura, A L; Dorantes, L M; Ramírez-González, B; López-Santos, M G; Valdes-Gonzalez, R

    2011-07-01

    Pig xenografts represent an alternative source of organs for transplantation. Immunosuppression can prevent rejection, but involves high risk and cost. New anti-rejection techniques have been developed; however, results have not been successful. Few studies have reported xenoantibody levels in xenotransplanted patients with diabetes and no patients have reported a clinical correlation. We analysed anti-galactose (Gal) and other anti-pig antibody (APA) levels in xenotransplanted patients with type 1 diabetes and the relation to the clinical outcome. Twenty-three patients with type 1 diabetes were transplanted with porcine islets inside a device without immunosuppression. Demographic characteristics, insulin dose and xenoantibody levels at different periods were recorded. Anti-Gal and anti-pig antibodies were measured through indirect enzyme-linked immunosorbent assay (ELISA) and haemolytic anti-pig antibody assay. More than 50% were female; the mean current age, current diabetes duration, diabetes duration at xenotransplantation and time post-transplantation were: 20·8, 11, 5·5 and 5·7 years, respectively. Insulin doses remained with a mean reduction greater than 33% in more than 50% of the patients. The lowest anti-Gal antibody levels were related to the highest insulin dose reductions. This relationship could be explained by the device, Sertoli cells and accommodation process. © 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.

  13. TRANSPLANTE DE ILHOTAS PANCREÁTICAS EM DISPOSITIVOS DE IMUNOISOLAMENTO CELULAR: RESULTADOS INICIAIS PANCREATIC ISLET TRANSPLANTATION IN CAPSULES OF CELLULAR IMMUNOISOLATION: PRELIMINARY RESULTS

    Directory of Open Access Journals (Sweden)

    E. D. Mente

    2001-01-01

    Full Text Available O transplante de pâncreas e de ilhotas pancreáticas vem apresentando grande desenvolvimento nos últimos anos. O isolamento das ilhotas em cápsulas com membrana semi-permeáveis pode ser tratamento de escolha para o diabetes, pois dispensa o uso de imunossupressores. O material ideal para a confecção de uma cápsula para o isolamento celular ainda permanece um sonho. Um novo material a base de látex natural foi implantado no subcutâneo de ratos normais e diabéticos para estudar a biocompatibilidade e a neoformação vascular. A análise após 21 dias de implante mostrou intensa formação capilar na interface membrana-tecido e pouco tecido fibrótico. Estes achados iniciais mostram que o material pode ter algum potencial para a confecção de dispositivos de isolamento celular.There have been great developments in pancreas and pancreatic islet cell transplantion in the last few years. The isolation of the islet cells in capsules with semi-permeable membranes may become ideal means of treating diabetes, and the use of immunossuppression could be avoided. The ideal material for the confection of the capsules has remained a dream. A new material derived from natural latex was implanted in the subcutaneous tissue of normal and diabetic rats to study the biocompatibility and the vascular neoformation. After 21 days, an analysis of the implant showed intense vascular neoformation on the membrane-tissue interface and little fibrotic tissue. The inicial results show great promise for utilization of this material in capsules for the isolation of cells.

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

    International Nuclear Information System (INIS)

    Mendez-Picon, G.; McGeorge, M.

    1983-01-01

    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)

  15. In vivo vascularization of anisotropic channeled porous polylactide-based capsules for islet transplantation: the effects of scaffold architecture and implantation site

    Czech Academy of Sciences Publication Activity Database

    Kasoju, Naresh; Kubies, Dana; Fabryová, E.; Kříž, J.; Kumorek, Marta M.; Sticová, E.; Rypáček, František

    2015-01-01

    Roč. 64, Suppl. 1 (2015), S75-S84 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : diabetes * islet transplantation * subcutaneous Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.643, year: 2015 http://www.biomed.cas.cz/physiolres/pdf/64%20Suppl%201/64_S75.pdf

  16. Total Pancreatectomy With Islet Auto-Transplantation (TPIAT): Summary of an NIDDK Workshop

    Science.gov (United States)

    Bellin, Melena D.; Gelrud, Andres; Arreaza-Rubin, Guillermo; Dunn, Ty B.; Humar, Abhinav; Morgan, Katherine A.; Naziruddin, Bashoo; Rastellini, Cristiana; Rickels, Michael R.; Schwarzenberg, Sarah J.; Andersen, Dana K.

    2014-01-01

    A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) focused on research gaps and opportunities in total pancreatectomy with islet autotransplantation (TPIAT) for the management of chronic pancreatitis (CP). The session was held on July 23, 2014 and structured into five sessions: (1) patient selection, indications, and timing; (2) technical aspects of TPIAT; (3) improving success of islet autotransplantation; (4) improving outcomes after total pancreatectomy; and (5) registry considerations for TPIAT. The current state of knowledge was reviewed; knowledge gaps and research needs were specifically highlighted. Common themes included the need to identify which patients best benefit from and when to intervene with TPIAT, current limitations of the surgical procedure, diabetes remission and the potential for improvement, opportunities to better address pain remission, GI complications in this population, and unique features of children with CP considered for TPIAT. The need for a multicenter patient registry that specifically addresses the complexities of CP and total pancreatectomy outcomes as well as post-surgical diabetes outcomes was repeatedly emphasized. PMID:25333399

  17. Characterisation of the xenogeneic immune response to microencapsulated fetal pig islet-like cell clusters transplanted into immunocompetent C57BL/6 mice.

    Directory of Open Access Journals (Sweden)

    Vijayaganapathy Vaithilingam

    Full Text Available Xenotransplantation of microencapsulated fetal pig islet-like cell clusters (FP ICCs offers a potential cellular therapy for type 1 diabetes. Although microcapsules prevent direct contact of the host immune system with the xenografted tissue, poor graft survival is still an issue. This study aimed to characterise the nature of the host immune cells present on the engrafted microcapsules and effects on encapsulated FP ICCs that were transplanted into immunocompetent mice. Encapsulated FP ICCs were transplanted into the peritoneal cavity of C57BL/6 mice. Grafts retrieved at days 1, 3, 7, 14 and 21 post-transplantation were analysed for pericapsular fibrotic overgrowth (PFO, cell viability, intragraft porcine gene expression, macrophages, myofibroblasts and intraperitoneal murine cytokines. Graft function was assessed ex vivo by insulin secretion studies. Xenogeneic immune response to encapsulated FP ICCs was associated with enhanced intragraft mRNA expression of porcine antigens MIP-1α, IL-8, HMGB1 and HSP90 seen within the first two weeks post-transplantation. This was associated with the recruitment of host macrophages, infiltration of myofibroblasts and collagen deposition leading to PFO which was evident from day 7 post-transplantation. This was accompanied by a decrease in cell viability and loss of FP ICC architecture. The only pro-inflammatory cytokine detected in the murine peritoneal flushing was TNF-α with levels peaking at day 7 post transplantation. This correlated with the onset of PFO at day 7 implying activated macrophages as its source. The anti-inflammatory cytokines detected were IL-5 and IL-4 with levels peaking at days 1 and 7, respectively. Porcine C-peptide was undetectable at all time points post-transplantation. PFO was absent and murine intraperitoneal cytokines were undetectable when empty microcapsules were transplanted. In conclusion, this study demonstrated that the macrophages are direct effectors of the xenogeneic

  18. Noradrenergic and cholinergic reinnervation of islet grafts in diabetic rats

    NARCIS (Netherlands)

    Houwing, H; VanAsperen, RM; VanderZee, EA; VanSuylichem, PTR; Oestreicher, AB; Steffens, AB; Strubbe, JH; Asperen, Roelie M. van

    1996-01-01

    Grafted islets become denervated due to the islet transplantation procedure. The aim of the present study was 1) to examine whether islet grafts in the liver, the spleen, and under the kidney capsule in rats become reinnervated following the transplantation and experimental procedures used in our

  19. Detection of the immunologic rejection after xeno-islet transplantation: a study by MR imaging enhanced with superparamagnetic iron oxide marking CD4+ T cell antibody

    International Nuclear Information System (INIS)

    Nie Wei; Tang Yiya; Rong Pengfei; Ye Bin; Ye Zheng; Tong Qiongjuan; Wang Wei

    2008-01-01

    Objective: To evaluate the feasibility of the diagnosis of the early immunologic rejection after xeno-islet transplantation by MR imaging enhanced with superparamagnetic iron oxide (SPIO) marking CD4 + T cell antibody. Methods: Two thousand neonatal porcine islets (NPI)were transplanted under the left renal capsule of BALB/C nude mice. When the grafts could be observed by MRI, 10 7 human PBMC was intraperitoneal injected to nude mouse models to reconstitute the human immunologic system, 20 mice were reconstituted. Before and 3,7,14 days after reconstitution of human immunologic system on BALB/C nude mice, MRI imaging was performed half an hour after intravenous injection of nano-immunomagnetic beads via vena caudatis to observe the grafts' MRI signal. BALB/C nude mice were sacrificed after MRI scanning immediately, the histopathologic examination was assessed on grafts, the results were compared with MRI results. And calculate the sensitivity, specificity, Youden index number and coincidence of the MRI for immunologic rejection. Results: Grafts can be observed by MRI 3 weeks after islet cell transplantation (before immunologic rejection modeling), there is no abnormal MRI signal detected in nude mice' graft region after microbeads injected. Seven days after building of immunologic rejection model, MRI hypo-signal in graft site is shown in the T 2 WI sequence after nano-bioprober injected. Histopathologic assessments were employed on grafts in nude mice immediately (HE and immunohistochemistry staining), the results shown that there are a lot of T lymphocyts infiltrated in graft region, implying the occurrence of immunologic rejection. And the sensitivity, specificity, Youden index number and coincidence is: (72.96±0.24)%, 100%, 0.73±0.24, (88.46±0.13)% respectively. The correct Kappa between the MRI and the imunohistochemistry staining was 0.76. Conclusion: The cellular immunological rejection to xeno-islet grarts can be assessed with nano-bioprobe with anti-CD4

  20. 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

  1. Rotational Transport of Islets: The Best Way for Islets to Get around?

    Directory of Open Access Journals (Sweden)

    Rupert Oberhuber

    2013-01-01

    Full Text Available Islet transplantation is a valid treatment option for patients suffering from type 1 diabetes mellitus. To assure optimal islet cell quality, specialized islet isolation facilities have been developed. Utilization of such facilities necessitates transportation of islet cells to distant institutions for transplantation. Despite its importance, a clinically feasible solution for the transport of islets has still not been established. We here compare the functionality of isolated islets from C57BL/6 mice directly after the isolation procedure as well as after two simulated transport conditions, static versus rotation. Islet cell quality was assessed using real-time live confocal microscopy. In vivo islet function after syngeneic transplantation was determined by weight and blood sugar measurements as well as by intraperitoneal glucose tolerance tests. Vascularization of islets was documented by fluorescence microscopy and immunohistochemistry. All viability parameters documented comparable cell viability in the rotary group and the group transplanted immediately after isolation. Functional parameters assessed in vivo displayed no significant difference between these two groups. Moreover, vascularization of islets was similar in both groups. In conclusion, rotary culture conditions allows the maintenance of highest islet quality for at least 15 h, which is comparable to that of freshly isolated islets.

  2. Sericin in the isolating solution improves the yield of islets isolated from the pancreas

    OpenAIRE

    Yokoi, Shigehiro; Murakami, Makoto; Morikawa, Mitsuhiro; Goi, Takanori; Yamaguchi, Akio; Terada, Satoshi

    2016-01-01

    Approximately half of the transplantable pancreatic islet tissue is lost during isolation, including the digestion and purification steps. Modifying the isolation method could increase the yield. This would enable the one donor-one recipient concept and improve the therapeutic effects of islet transplantation. This study aims to improve islet transplantation by increasing the yield of islets from the pancreas, both the number of islets and their size. Therefore, we used a sericin-containing i...

  3. Selective Osmotic Shock (SOS)-Based Islet Isolation for Microencapsulation.

    Science.gov (United States)

    Enck, Kevin; McQuilling, John Patrick; Orlando, Giuseppe; Tamburrini, Riccardo; Sivanandane, Sittadjody; Opara, Emmanuel C

    2017-01-01

    Islet transplantation (IT) has recently been shown to be a promising alternative to pancreas transplantation for reversing diabetes. IT requires the isolation of the islets from the pancreas, and these islets can be used to fabricate a bio-artificial pancreas. Enzymatic digestion is the current gold standard procedure for islet isolation but has lingering concerns. One such concern is that it has been shown to damage the islets due to nonselective tissue digestion. This chapter provides a detailed description of a nonenzymatic method that we are exploring in our lab as an alternative to current enzymatic digestion procedures for islet isolation from human and nonhuman pancreatic tissues. This method is based on selective destruction and protection of specific cell types and has been shown to leave the extracellular matrix (ECM) of islets intact, which may thus enhance islet viability and functionality. We also show that these SOS-isolated islets can be microencapsulated for transplantation.

  4. A Small Molecule Swertisin from Enicostemma littorale Differentiates NIH3T3 Cells into Islet-Like Clusters and Restores Normoglycemia upon Transplantation in Diabetic Balb/c Mice

    Directory of Open Access Journals (Sweden)

    Nidheesh Dadheech

    2013-01-01

    Full Text Available Aim. Stem cell therapy is one of the upcoming therapies for the treatment of diabetes. Discovery of potent differentiating agents is a prerequisite for increasing islet mass. The present study is an attempt to screen the potential of novel small biomolecules for their differentiating property into pancreatic islet cells using NIH3T3, as representative of extra pancreatic stem cells/progenitors. Methods. To identify new agents that stimulate islet differentiation, we screened various compounds isolated from Enicostemma littorale using NIH3T3 cells and morphological changes were observed. Characterization was performed by semiquantitative RT-PCR, Q-PCR, immunocytochemistry, immunoblotting, and insulin secretion assay for functional response in newly generated islet-like cell clusters (ILCC. Reversal of hyperglycemia was monitored after transplanting ILCC in STZ-induced diabetic mice. Results. Among various compounds tested, swertisin, an isolated flavonoid, was the most effective in differentiating NIH3T3 into endocrine cells. Swertisin efficiently changed the morphology of NIH3T3 cells from fibroblastic to round aggregate cell cluster in huge numbers. Dithizone (DTZ stain primarily confirmed differentiation and gene expression studies signified rapid onset of differentiation signaling cascade in swertisin-induced ILCC. Molecular imaging and immunoblotting further confirmed presence of islet specific proteins. Moreover, glucose induced insulin release (in vitro and decreased fasting blood glucose (FBG (in vivo in transplanted diabetic BALB/c mice depicted functional maturity of ILCC. Insulin and glucagon expression in excised islet grafts illustrated survival and functional integrity. Conclusions. Rapid induction for islet differentiation by swertisin, a novel herbal biomolecule, provides low cost and readily available differentiating agent that can be translated as a therapeutic tool for effective treatment in diabetes.

  5. Effects of Acute Cytomegalovirus Infection on Rat Islet Allograft Survival

    NARCIS (Netherlands)

    Smelt, M. J.; Faas, M. M.; Melgert, B. N.; de Vos, P.; de Haan, Bart; de Haan, Aalzen

    2011-01-01

    Transplantation of pancreatic islets is a promising therapy for the treatment of type 1 diabetes mellitus. However, long-term islet graft survival rates are still unsatisfactory low. In this study we investigated the role of cytomegalovirus (CMV) in islet allograft failure. STZ-diabetic rats

  6. Factors influencing insulin secretion from encapsulated islets

    NARCIS (Netherlands)

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

    2003-01-01

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

  7. Human pancreatic islet progenitor cells demonstrate phenotypic ...

    Indian Academy of Sciences (India)

    Prakash

    The increasing scarcity in number of human pancreatic islets available for transplantation in type 1 diabetes (Shapiro et al. 2005, 2006), has accentuated the need for research in exploring alternative sources of insulin-producing cells for cell based therapy in diabetes. Since in vitro culture of islet β-cells demonstrates loss in ...

  8. Sensing and Sensibility: Single-Islet-based Quality Control Assay of Cryopreserved Pancreatic Islets with Functionalized Hydrogel Microcapsules.

    Science.gov (United States)

    Chen, Wanyu; Shu, Zhiquan; Gao, Dayong; Shen, Amy Q

    2016-01-21

    Despite decades of research and clinical studies of islet transplantations, finding simple yet reliable islet quality assays that correlate accurately with in vivo potency is still a major challenge, especially for real-time and single-islet-based quality assessment. Herein, proof-of-concept studies of a cryopreserved microcapsule-based quality control assays are presented for single islets. Individual rat pancreatic islets and fluorescent oxygen-sensitive dye (FOSD) are encapsulated in alginate hydrogel microcapsules via a microfluidic device. To test the susceptibility of the microcapsules and the FOSD to cryopreservation, the islet microcapsules containing FOSD are cryopreserved and the islet functionalities (adenosine triphosphate, static insulin release measurement, and oxygen consumption rate) are assessed after freezing and thawing steps. The cryopreserved islet capsules with FOSD remain functional after encapsulation and freezing/thawing procedures, validating a simple yet reliable individual-islet-based quality control method for the entire islet processing procedure prior to transplantation. This work also demonstrates that the functionality of cryopreserved islets can be improved by introducing trehalose into the routinely used cryoprotectant dimethyl sulfoxide. The functionalized alginate hydrogel microcapsules with embedded FOSD and optimized cryopreservation protocol presented in this work serve as a versatile islet quality assay and offer tremendous promise for tackling existing challenges in islet transplantation procedures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. PROGRESS IN CLINICAL ENCAPSULATED ISLET XENOTRANSPLANTATION

    Science.gov (United States)

    Cooper, David K.C.; Matsumoto, Shinichi; Abalovich, Adrian; Itoh, Takeshi; Mourad, Nizar I.; Gianello, Pierre R; Wolf, Eckhard; Cozzi, Emanuele

    2016-01-01

    At the 2015 combined congress of the CTS, IPITA, and IXA, a symposium was held to discuss recent progress in pig islet xenotransplantation. The presentations focused on 5 major topics – (i) the results of 2 recent clinical trials of encapsulated pig islet transplantation, (ii) the inflammatory response to encapsulated pig islets, (iii) methods to improve the secretion of insulin by pig islets, (iv) genetic modifications to the islet-source pigs aimed to protect the islets from the primate immune and/or inflammatory responses, and (v) regulatory aspects of clinical pig islet xenotransplantation. Trials of microencapsulated porcine islet transplantation to treat unstable type 1 diabetic patients have been associated with encouraging preliminary results. Further advances to improve efficacy may include (i) transplantation into a site other than the peritoneal cavity, which might result in better access to blood, oxygen, and nutrients; (ii) the development of a more biocompatible capsule and/or the minimization of a foreign body reaction; (iii) pig genetic modification to induce a greater secretion of insulin by the islets, and/or to reduce the immune response to islets released from damaged capsules; and (iv) reduction of the inflammatory response to the capsules/islets by improvements in the structure of the capsules and/or in genetic-engineering of the pigs and/or in some form of drug therapy. Ethical and regulatory frameworks for islet xenotransplantation are already available in several countries, and there is now a wider international perception of the importance of developing an internationally-harmonized ethical and regulatory framework. PMID:27482959

  10. Induction of Protective Genes Leads to Islet Survival and Function

    Directory of Open Access Journals (Sweden)

    Hongjun Wang

    2011-01-01

    Full Text Available Islet transplantation is the most valid approach to the treatment of type 1 diabetes. However, the function of transplanted islets is often compromised since a large number of β cells undergo apoptosis induced by stress and the immune rejection response elicited by the recipient after transplantation. Conventional treatment for islet transplantation is to administer immunosuppressive drugs to the recipient to suppress the immune rejection response mounted against transplanted islets. Induction of protective genes in the recipient (e.g., heme oxygenase-1 (HO-1, A20/tumor necrosis factor alpha inducible protein3 (tnfaip3, biliverdin reductase (BVR, Bcl2, and others or administration of one or more of the products of HO-1 to the donor, the islets themselves, and/or the recipient offers an alternative or synergistic approach to improve islet graft survival and function. In this perspective, we summarize studies describing the protective effects of these genes on islet survival and function in rodent allogeneic and xenogeneic transplantation models and the prevention of onset of diabetes, with emphasis on HO-1, A20, and BVR. Such approaches are also appealing to islet autotransplantation in patients with chronic pancreatitis after total pancreatectomy, a procedure that currently only leads to 1/3 of transplanted patients being diabetes-free.

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

    Science.gov (United States)

    Shin, Soojeong; Yoo, Young Je

    2013-12-01

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

  12. Rapamycin combined with anti-CD45RB mAb and IL-10 or with G-CSF induces tolerance in a stringent mouse model of islet transplantation.

    Directory of Open Access Journals (Sweden)

    Nicola Gagliani

    Full Text Available BACKGROUND: A large pool of preexisting alloreactive effector T cells can cause allogeneic graft rejection following transplantation. However, it is possible to induce transplant tolerance by altering the balance between effector and regulatory T (Treg cells. Among the various Treg-cell types, Foxp3(+Treg and IL-10-producing T regulatory type 1 (Tr1 cells have frequently been associated with tolerance following transplantation in both mice and humans. Previously, we demonstrated that rapamycin+IL-10 promotes Tr1-cell-associated tolerance in Balb/c mice transplanted with C57BL/6 pancreatic islets. However, this same treatment was unsuccessful in C57BL/6 mice transplanted with Balb/c islets (classified as a stringent transplant model. We accordingly designed a protocol that would be effective in the latter transplant model by simultaneously depleting effector T cells and fostering production of Treg cells. We additionally developed and tested a clinically translatable protocol that used no depleting agent. METHODOLOGY/PRINCIPAL FINDINGS: Diabetic C57BL/6 mice were transplanted with Balb/c pancreatic islets. Recipient mice transiently treated with anti-CD45RB mAb+rapamycin+IL-10 developed antigen-specific tolerance. During treatment, Foxp3(+Treg cells were momentarily enriched in the blood, followed by accumulation in the graft and draining lymph node, whereas CD4(+IL-10(+IL-4(- T (i.e., Tr1 cells localized in the spleen. In long-term tolerant mice, only CD4(+IL-10(+IL-4(- T cells remained enriched in the spleen and IL-10 was key in the maintenance of tolerance. Alternatively, recipient mice were treated with two compounds routinely used in the clinic (namely, rapamycin and G-CSF; this drug combination promoted tolerance associated with CD4(+IL-10(+IL-4(- T cells. CONCLUSIONS/SIGNIFICANCE: The anti-CD45RB mAb+rapamycin+IL-10 combined protocol promotes a state of tolerance that is IL-10 dependent. Moreover, the combination of rapamycin+G-CSF induces

  13. 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

  14. Microencapsulation of Pancreatic Islets for Use in a Bioartificial Pancreas

    Science.gov (United States)

    Opara, Emmanuel C.; McQuilling, John P.; Farney, Alan C.

    2013-01-01

    Islet transplantation is the most exciting treatment option for individuals afflicted with Type 1 diabetes. However, the severe shortage of human pancreas and the need to use risky immunosuppressive drugs to prevent transplant rejection remain two major obstacles for the routine use of islet transplantation in diabetic patients. Successful development of a bioartificial pancreas using the approach of microencapsulation with perm-selective coating of islets with biopolymers for graft immunoisolation holds tremendous promise for diabetic patients because it has great potential to overcome these two barriers. In this chapter, we provide a detailed description of the microencapsulation process. PMID:23494435

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

    Science.gov (United States)

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

    2017-07-01

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

  16. Genetically Engineered Human Islets Protected From CD8-mediated Autoimmune Destruction In Vivo

    NARCIS (Netherlands)

    Zaldumbide, Arnaud; Alkemade, Gonnie; Carlotti, Francoise; Nikolic, Tatjana; Abreu, Joana R. F.; Engelse, Marten A.; Skowera, Anja; de Koning, Eelco J.; Peakman, Mark; Roep, Bart O.; Hoeben, Rob C.; Wiertz, Emmanuel J. H. J.

    Islet transplantation is a promising therapy for type 1 diabetes, but graft function and survival are compromised by recurrent islet autoimmunity. Immunoprotection of islets will be required to improve clinical outcome. We engineered human beta cells to express herpesvirus-encoded immune-evasion

  17. Pleckstrin homology-like domain family A, member 3 (PHLDA3 deficiency improves islets engraftment through the suppression of hypoxic damage.

    Directory of Open Access Journals (Sweden)

    Naoaki Sakata

    Full Text Available Islet transplantation is a useful cell replacement therapy that can restore the glycometabolic function of severe diabetic patients. It is known that many transplanted islets failed to engraft, and thus, new approaches for overcoming graft loss that may improve the outcome of future clinical islet transplantations are necessary. Pleckstrin homology-like domain family A, member 3 (PHLDA3 is a known suppressor of neuroendocrine tumorigenicity, yet deficiency of this gene increases islet proliferation, prevents islet apoptosis, and improves their insulin-releasing function without causing tumors. In this study, we examined the potential use of PHLDA3-deficient islets in transplantation. We observed that: 1 transplanting PHLDA3-deficient islets into diabetic mice significantly improved their glycometabolic condition, 2 the improved engraftment of PHLDA3-deficient islets resulted from increased cell survival during early transplantation, and 3 Akt activity was elevated in PHLDA3-deficient islets, especially under hypoxic conditions. Thus, we determined that PHLDA3-deficient islets are more resistant against stresses induced by islet isolation and transplantation. We conclude that use of islets with suppressed PHLDA3 expression could be a novel and promising treatment for improving engraftment and consequent glycemic control in islet transplantation.

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

    Science.gov (United States)

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

    1992-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Klearchos K Papas

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

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

    Directory of Open Access Journals (Sweden)

    Chengshi Wang

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

  1. TRANSPLANTATION

    African Journals Online (AJOL)

    stage kidney disease. There is good evidence that transplantation improves both the quality and quantity of life in renal transplant recipients when compared with dialysis.1,2. Living donor kidney transplantation has gained popularity, not only owing ...

  2. Novel culture technique involving an histone deacetylase inhibitor reduces the marginal islet mass to correct streptozotocin-induced diabetes.

    Science.gov (United States)

    Shin, Jun-Seop; Min, Byoung-Hoon; Lim, Jong-Yeon; Kim, Byoung-Keun; Han, Hyun-Ju; Yoon, Kun-Ho; Kim, Sang-Joon; Park, Chung-Gyu

    2011-01-01

    Islet transplantation is limited by the difficulties in isolating the pancreatic islets from the cadaveric donor and maintaining them in culture. To increase islet viability and function after isolation, here we present a novel culture technique involving an histone deacetylase inhibitor (HDACi) to rejuvenate the isolated islets. Pancreatic islets were isolated from Sprague-Dawley (SD) rats and one group (FIs; freshly isolated islets) was used after overnight culture and the other group (RIs; rejuvenated islet) was subjected to rejuvenation culture procedure, which is composed of three discrete steps including degranulation, chromatin remodeling, and regranulation. FIs and RIs were compared with regard to intracellular insulin content, glucose-stimulated insulin secretion (GSIS) capacity, gene expression profile, viability and apoptosis rate under oxidative stresses, and the engraftment efficacy in the xenogeneic islet transplantation models. RIs have been shown to have 1.9 ± 0.28- and 1.7 ± 0.31-fold greater intracellular insulin content and GSIS capacity, respectively, than FIs. HDACi increased overall histone acetylation levels, with inducing increased expression of many genes including insulin 1, insulin 2, GLUT2, and Ogg1. This enhanced islet capacity resulted in more resistance against oxidative stresses and increase of the engraftment efficacy shown by reduction of twofold marginal mass of islets in xenogeneic transplantation model. In conclusion, a novel rejuvenating culture technique using HDACi as chromatin remodeling agents improved the function and viability of the freshly isolated islets, contributing to the reduction of islet mass for the control of hyperglycemia in islet transplantation.

  3. 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...... of diabetes type II, while revealing the structure(s) of islet amyloid fibrils is necessary for potential design of therapeutic agents....

  4. Culture of Impure Human Islet Fractions in the Presence of Alpha-1-Antitrypsin Prevents Insulin Cleavage and Improves Islet Recovery

    Science.gov (United States)

    Loganathan, G.; Dawra, R.K.; Pugazhenthi, S.; Wiseman, A.C.; Sanders, M.A.; Saluja, A.K.; Sutherland, D.E.R.; Hering, B.J.; Balamurugan, A.N.

    2010-01-01

    Background Exocrine tissue is commonly cotransplanted with islets in autografting and allotransplantation of impure preparations. Proteases and insulin are released by acinar cells and islets, respectively, during pretransplantation culture and also systemically after transplantation. We hypothesized that released proteases could cleave insulin molecules and that addition of alpha 1 antitrypsin (A1AT) to impure islet cultures would block this cleavage, improving islet recovery and function. Methods Trypsin, chymotrypsin, and elastase (TCE) activity and insulin levels were measured in culture supernates of pure (n = 5) and impure (n = 5) islet fractions, which were isolated from deceased donors. SDS-PAGE was used to detect insulin after incubation with proteases. We assessed the effects of A1AT supplementation (0.5 mg/mL; n = 4] on TCE activity, insulin levels, culture recovery, and islet quality. The ultrastructure of islets exposed to TCE versus control medium was examined using electron microscopy (EM). Results Protease (TCE) activity in culture supernates was directly proportional to the percentage purity of islets: pure, impure, or highly impure. Increasingly lower levels of insulin were detected in culture supernates with higher protease activity levels. Insulin levels measured in supernates of 2000 IE aliquots of impure and highly impure islet preparations were 61 ± 23.7% and 34 ± 33% of that in pure preparations, respectively. Incubation with commercially available proteases (TCE) or exocrine acinar cell supernates cleaved insulin molecules as assessed using SDS-PAGE. Addition of A1AT to impure islet preparations reduced protease activity and restored normal insulin levels as detected using enzyme-linked immunosorbent assay (ELISA) and SDS-PAGE of culture supernates. A1AT improved insulin levels to 98% ± 1.3% in impure and 78% ± 34.2% in highly impure fractions compared with pure islet fractions. A1AT supplementation improved postculture recovery of

  5. Glucose tolerance and plasma insulin response to intravenous glucose infusion and test meal in rats with microencapsulated islet allografts

    NARCIS (Netherlands)

    Fritschy, W.M.; Strubbe, J.H.; Wolters, G.H.J.; Schilfgaarde, R. van

    Albino Oxford rats made diabetic with 75 mg/kg streptozotocin were intraperitoneally transplanted with 2500-2900 alginate-polylysine microencapsulated Lewis islets (n = 9, total islet tissue volume 8.0-11.0-mu-l), or a similar volume of non-encapsulated Lewis islets (n = 5). All rats with

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

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    Jyuhn-Huarng Juang

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

  7. Automated Analysis of Microscopic Images of Isolated Pancreatic Islets

    Czech Academy of Sciences Publication Activity Database

    Habart, D.; Švihlík, J.; Schier, Jan; Cahová, M.; Girman, P.; Zacharovová, K.; Berková, Z.; Kříž, J.; Fabryová, E.; Kosinová, L.; Papáčková, Z.; Kybic, J.; Saudek, F.

    2016-01-01

    Roč. 25, č. 12 (2016), s. 2145-2156 ISSN 0963-6897 Grant - others:GA ČR(CZ) GA14-10440S Institutional support: RVO:67985556 Keywords : enumeration of islets * image processing * image segmentation * islet transplantation * machine-learning * quality control Subject RIV: IN - Informatics, Computer Science Impact factor: 3.006, year: 2016 http://library.utia.cas.cz/separaty/2016/ZOI/schier-0465945.pdf

  8. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Rehana Akter

    2016-01-01

    Full Text Available The hormone islet amyloid polypeptide (IAPP, or amylin plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.

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

    Science.gov (United States)

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

    2014-01-01

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

  10. PD-L1 Deficiency within Islets Reduces Allograft Survival in Mice.

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    Dongxia Ma

    Full Text Available Islet transplantation may potentially cure type 1 diabetes mellitus (T1DM. However, immune rejection, especially that induced by the alloreactive T-cell response, remains a restraining factor for the long-term survival of grafted islets. Programmed death ligand-1 (PD-L1 is a negative costimulatory molecule. PD-L1 deficiency within the donor heart accelerates allograft rejection. Here, we investigate whether PD-L1 deficiency in donor islets reduces allograft survival time.Glucose Stimulation Assays were performed to evaluate whether PD-L1 deficiency has detrimental effects on islet function. Islets isolated from PDL1-deficient mice or wild- type (WT mice (C57BL/6j were implanted beneath the renal capsule of streptozotocin (STZ-induced diabetic BALB/c mice. Blood glucose levels and graft survival time after transplantation were monitored. Moreover, we analyzed the residual islets, infiltrating immune cells and alloreactive cells from the recipients.PD-L1 deficiency within islets does not affect islet function. However, islet PD-L1 deficiency increased allograft rejection and was associated with enhanced inflammatory cell infiltration and recipient T-cell alloreactivity.This is the first report to demonstrate that PD-L1 deficiency accelerated islet allograft rejection and regulated recipient alloimmune responses.

  11. Alginate Microencapsulation of Human Islets Does Not Increase Susceptibility to Acute Hypoxia

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    I. K. Hals

    2013-01-01

    Full Text Available Islet transplantation in diabetes is hampered by the need of life-long immunosuppression. Encapsulation provides partial immunoprotection but could possibly limit oxygen supply, a factor that may enhance hypoxia-induced beta cell death in the early posttransplantation period. Here we tested susceptibility of alginate microencapsulated human islets to experimental hypoxia (0.1–0.3% O2 for 8 h, followed by reoxygenation on viability and functional parameters. Hypoxia reduced viability as measured by MTT by 33.8±3.5% in encapsulated and 42.9±5.2% in nonencapsulated islets (P<0.2. Nonencapsulated islets released 37.7% (median more HMGB1 compared to encapsulated islets after hypoxic culture conditions (P<0.001. Glucose-induced insulin release was marginally affected by hypoxia. Basal oxygen consumption was equally reduced in encapsulated and nonencapsulated islets, by 22.0±6.1% versus 24.8±5.7%. Among 27 tested cytokines/chemokines, hypoxia increased the secretion of IL-6 and IL-8/CXCL8 in both groups of islets, whereas an increase of MCP-1/CCL2 was seen only with nonencapsulated islets. Conclusion. Alginate microencapsulation of human islets does not increase susceptibility to acute hypoxia. This is a positive finding in relation to potential use of encapsulation for islet transplantation.

  12. 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.

  13. Intraportal nicotine infusion in rats decreases hepatic blood flow through endothelin-1 and both endothelin A and endothelin B receptors

    International Nuclear Information System (INIS)

    Hashimoto, Takashi; Yoneda, Masashi; Shimada, Tadahito; Kurosawa, Mieko; Terano, Akira

    2004-01-01

    Smoking has been demonstrated to aggravate liver injury. Nicotine, a major pharmacological component of tobacco smoke, affects a multitude of functions. Smoking and nicotine induce synthesis of endothelin (ET)-1. The effect of intraportal infusion of nicotine on hepatic circulation and an involvement of ET-1 and ET receptor in the action of nicotine were investigated in rats. Nicotine (0-100 μg/kg/h) was infused into the portal vein of urethane-anesthetized rats, and changes of hepatic blood flow were evaluated. Intraportal infusion of nicotine dose-dependently decreased hepatic blood flow and increased portal pressure without any alteration of heart rate or arterial blood pressure. This action of intraportal nicotine was completely abolished by pretreatment of ET-1 antibody. Either BQ485 (ET A receptor antagonist) or BQ788 (ET B receptor antagonist) partially reversed the effect of nicotine, and combination of BQ788 and BQ485 completely abolished it. These findings suggest that nicotine inhibits hepatic circulation through ET-1, and ET A and ET B receptor

  14. Synergistic Effect of Hyperglycemia and Suppression on Adult Mouse Islet Beta Cell Replication

    Directory of Open Access Journals (Sweden)

    Szu-Tah Chen

    2012-01-01

    Full Text Available The complementary role of hyperglycemia and suppression on islet beta cell regeneration was investigated in a syngeneic mouse model. gene silencing was performed by infecting islets of C57BL/6 with shRNA lentiviral particles. At 54 hours after viral infection, protein content in cultured targeting islets was 22% of that in freshly isolated islets. Six days after transplantation to diabetic mice, targeting islet graft had considerably more cells with Ki67-staining nuclei than nontargeting islets. The mice in the targeting-islet group had a significantly shorter duration of temporary hyperglycaemia than mice in the non-targeting-islet group. The long-term ex vivo beneficial effect of silencing on graft function was also indicated by the significantly higher cumulative cure rate for diabetes in mice receiving 200 targeting islets than that in mice receiving 200 non-targeting islets. Our data suggest that hyperglycemia and persistent suppression have a synergistic effect on islet beta cell replication in adult mice.

  15. 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.

  16. Fetal rat pancreas transplantation in BB rats: immunohistochemical and functional evaluation

    DEFF Research Database (Denmark)

    Yderstræde, Knud Bonnet; Starklint, Henrik; Steinbrüchel, Daniel Andreas

    1993-01-01

    Spontaneously diabetic BB/Wor rats received either a syngeneic fetal pancreas transplant or adult islets. In the former, 4-8 fetal pancreases were transplanted, and in the latter, 3-5000 islets. Transplantation was performed by transferring a blood clot containing the pancreases or islets...... to the renal subcapsular space. Insulin therapy was undertaken postoperatively, except in one experiment with adult islets. Of the fetal pancreas transplanted BB rats, 52% became normoglycaemic, and 21% remained so throughout an observation period of 10 months. Nephrectomy caused a prompt return of diabetes....... The histological appearance of the grafts transplanted to the diabetic animals closely resembled that of grafts transplanted to normal rats in a parallel series. For comparison a group of BB rats received a syngeneic transplant of isolated adult islets from WF rats or BBW rats. Following adult islet...

  17. Alginate Microencapsulation of Human Islets Does Not Increase Susceptibility to Acute Hypoxia

    Science.gov (United States)

    Hals, I. K.; Rokstad, A. M.; Strand, B. L.; Oberholzer, J.; Grill, V.

    2013-01-01

    Islet transplantation in diabetes is hampered by the need of life-long immunosuppression. Encapsulation provides partial immunoprotection but could possibly limit oxygen supply, a factor that may enhance hypoxia-induced beta cell death in the early posttransplantation period. Here we tested susceptibility of alginate microencapsulated human islets to experimental hypoxia (0.1–0.3% O2 for 8 h, followed by reoxygenation) on viability and functional parameters. Hypoxia reduced viability as measured by MTT by 33.8 ± 3.5% in encapsulated and 42.9 ± 5.2% in nonencapsulated islets (P microencapsulation of human islets does not increase susceptibility to acute hypoxia. This is a positive finding in relation to potential use of encapsulation for islet transplantation. PMID:24364039

  18. Alotransplante de ilhotas de Langerhans no fígado de ratos submetidos a manipulação tímica com células dendríticas Alogenic islet transplantation on the rat liver after alogenic dendritic cells injection in the thymus

    Directory of Open Access Journals (Sweden)

    Eleazar Chaib

    2005-03-01

    a reação do receptor contra o enxerto, prolongando a sobrevida média das ilhotas e, possivelmente, levando ao estado de tolerância imunológica, induziu ao processo de rejeição aguda precoce.BACKGROUND: The major indication for pancreas or islet transplantation is diabetes mellitus tipe I. This process has to suply the insulin necessity keeping glucose under control. AIM: We studied alogenic islet transplantation on the rat liver, Wistar (RT1u to Lewis (RT1¹ as a recipient. Control group (n = 8 and dendritic cell group (n = 9 respectively with injection of Hanks solution and dendritic cells in the thymus before islet transplantation. MATERIAL AND METHODS: With the method of isolation and purification of the islets we obtained both in the control group 3637 ± 783,3 islets with purity of 85 ± 3,52% and dendritic cell group 3268 ± 378 islets with purity of 87 ± 4,47%. The dendritic cells were retrieved from the spleen and we obtained 3,34 x 105±1,16 cells. Diabetes was induced by i.v. streptozotocin. RESULTS: Control group the transplantation of 3637 ± 783,3 islets in the rat liver normalized glucose test, 7,21 ± 0,57 mmol/L in the second post-operative day. Acute rejection came in the 10 postoperative day with significantly increase of glucose test. Dendritic cell group, the transplantation of 3258 ± 378 islets in the rat liver, normalized the glucose test was 9,3 ± 2,85 mmoL/L in the second postoperative day. From the 4th postoperative day to 10th postoperative day the glucose test increase significantly showing an early acute rejection. CONCLUSION: The injection of dendritic cells in the thymus before alogenic islet transplantation in the rat liver lead to an early acute rejection.

  19. Alotransplante de ilhotas de Langerhans no fígado de ratos submetidos a manipulação tímica com células não-parenquimatosas Allogenic islet transplantation on the rat liver after allogenic nonparenchymal cells injection in the thymus

    Directory of Open Access Journals (Sweden)

    Eleazar Chaib

    2006-12-01

    éticos, antes do alotransplante de ilhotas de Langerhans no fígado, ao contrário de inibir a reação do receptor contra o enxerto, prolongando a sobrevida média das ilhotas e, possivelmente, levando ao estado de tolerância imunológica, induziu ao processo de rejeição aguda precoce.BACKGROUD: The major indication for pancreas or islet transplantation is diabetes mellitus type I. This process has to supply the insulin necessity keeping glucose under control AIM: We studied allogenic islet transplantation on the rat liver, Wistar (RT1u to Lewis (RT1¹ as a recipient. Control group (n = 8 and nonparenchymal cell group (n = 8 respectively with injection of Hanks solution and nonparenchymal cells in the thymus before islet transplantation. MATERIAL AND METHODS: With the method of isolation and purification of the islets we obtained both in the control group 3.637 ± 783,3 islets with purity of 85 ± 3,52% and nonparenchymal cell group 3.270 ± 770 islets with purity of 84,25 ± 2,76%. The nonparenchymal cells were retrieved from the liver and we obtained 2 x 106 cells. Diabetes was induced by i.v. streptozotocin RESULTS: Control group the transplantation of 3.637 ± 783,3 islets in the rat liver normalized glucose test, 7,21 ± 0,57 mmol/L in the 2nd postoperative day. Acute rejection came in the 6th postoperative day with significantly increase of glucose test in nonparenchymal cell group, the transplantation of 3.270 ± 770 islets in the rat liver, almost normalized the glucose test was 17,95 ± 5,33 mmol/L in the 2nd postoperative day. From the 4th postoperative day to 10th postoperative day. The glucose test increase significantly showing an early acute rejection CONCLUSION: The injection of nonparenchymal cells in the thymus before allogenic islet transplantation in the rat liver lead to an early acute rejection.

  20. Human mesenchymal stem cells protect human islets from pro-inflammatory cytokines.

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    Telford Y Yeung

    Full Text Available Transplantation of human islets is an attractive alternative to daily insulin injections for patients with type 1 diabetes. However, the majority of islet recipients lose graft function within five years. Inflammation is a primary contributor to graft loss, and inhibiting pro-inflammatory cytokine activity can reverse inflammation mediated dysfunction of islet grafts. As mesenchymal stem cells (MSCs possess numerous immunoregulatory properties, we hypothesized that MSCs could protect human islets from pro-inflammatory cytokines. Five hundred human islets were co-cultured with 0.5 or 1.0 × 10(6 human MSCs derived from bone marrow or pancreas for 24 hours followed by 48 hour exposure to interferon-γ, tumor necrosis factor-α and interleukin 1β. Controls include islets cultured alone (± cytokines and with human dermal fibroblasts (± cytokines. For all conditions, glucose stimulated insulin secretion (GSIS, total islet cellular insulin content, islet β cell apoptosis, and potential cytoprotective factors secreted in the culture media were determined. Cytokine exposure disrupted human islet GSIS based on stimulation index and percentage insulin secretion. Conversely, culture with 1.0 × 10(6 bMSCs preserved GSIS from cytokine treated islets. Protective effects were not observed with fibroblasts, indicating that preservation of human islet GSIS after exposure to pro-inflammatory cytokines is MSC dependent. Islet β cell apoptosis was observed in the presence of cytokines; however, culture of bMSCs with islets prevented β cell apoptosis after cytokine treatment. Hepatocyte growth factor (HGF as well as matrix metalloproteinases 2 and 9 were also identified as putative secreted cytoprotective factors; however, other secreted factors likely play a role in protection. This study, therefore, demonstrates that MSCs may be beneficial for islet engraftment by promoting cell survival and reduced inflammation.

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

    Directory of Open Access Journals (Sweden)

    Goichi Yanai

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

  2. [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.

  3. A Combinatorial Protein Microarray for Probing Materials Interaction with Pancreatic Islet Cell Populations

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    Bahman Delalat

    2016-08-01

    Full Text Available Pancreatic islet transplantation has become a recognized therapy for insulin-dependent diabetes mellitus. During isolation from pancreatic tissue, the islet microenvironment is disrupted. The extracellular matrix (ECM within this space not only provides structural support, but also actively signals to regulate islet survival and function. In addition, the ECM is responsible for growth factor presentation and sequestration. By designing biomaterials that recapture elements of the native islet environment, losses in islet function and number can potentially be reduced. Cell microarrays are a high throughput screening tool able to recreate a multitude of cellular niches on a single chip. Here, we present a screening methodology for identifying components that might promote islet survival. Automated fluorescence microscopy is used to rapidly identify islet derived cell interaction with ECM proteins and immobilized growth factors printed on arrays. MIN6 mouse insulinoma cells, mouse islets and, finally, human islets are progressively screened. We demonstrate the capability of the platform to identify ECM and growth factor protein candidates that support islet viability and function and reveal synergies in cell response.

  4. Prolonged Survival of Subcutaneous Allogeneic Islet Graft by Donor Chimerism without Immunosuppressive Treatment

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    Brend Ray-Sea Hsu

    2017-01-01

    Full Text Available The aim of this study was to investigate whether tolerance-induced protection of islets in the renal subcapsular space can also prevent subcutaneous allogeneic islets from being rejected. We used bone marrow stem cells from C57BL/6 (H2b mice to construct donor chimerism in conditioned diabetic BALB/c (H2d mice and investigated the effect of donor chimerism on engraftment and survival of subcutaneously transplanted allogeneic islets in streptozotocin-induced diabetic mice. We also studied the anti-inflammatory effect of mesenchymal stem cell on islet engraftment. Full but not low-grade or no donor chimerism was associated with successful engraftment of allogeneic islets and restoration of normoglycemia in the treated diabetic mice. The temporary hyperglycemia was 11 ± 1 versus 19 ± 5 days (p<0.05 for the mice with full donor chimerism with transplanted islets in the renal subcapsular space versus the subcutaneous space, respectively. Cotransplantation of mesenchymal stem cell did not enhance alloislet engraftment. Full multilineage donor chimerism was associated with a higher transient expansion of CD11b+ and Gr-1+ myeloid progenitor cells and effector memory CD4 and CD8 T cells. In conclusion, full donor chimerism protected both renal subcapsular and subcutaneous allogeneic islets in this rodent transplantation model.

  5. VEGF-conjugated alginate hydrogel prompt angiogenesis and improve pancreatic islet engraftment and function in type 1 diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Nina; Han, Yongming [Department of Anatomy, Basic Medical College, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Xu, Hanlin [Pharmacy Faculty, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Gao, Yisen; Yi, Tao [Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Yao, Jiale; Dong, Li; Cheng, Dejun [Basic Medical College, Hubei University of Chinese Medicine, Wuhan, Hubei (China); Chen, Zebin, E-mail: chenzebin-hbtcm@outlook.com [Acupuncture and Moxibustion College, Hubei University of Chinese Medicine/Hubei Provincial Collaborative Innovation Center of Preventive Treatment by Acupuncture and Moxibustion, Wuhan, Hubei (China)

    2016-02-01

    Type 1 diabetes was a life-long disease that affected numerous people around the world. Insulin therapy has its limitations that may involve hyperglycemia and heavy burden of patient by repeated dose. Islet transplantation emerged as a promising approach to reach periodical reverse of diabetes, however, transplanted islets suffer from foreign body reaction and lack of nutrition and oxygen supply, especially in the blood-vessel-shortage subcutaneous site which was preferred by patient and surgeon. In this study, we designed and synthesized a vascular endothelial growth factor (VEGF) conjugated alginate material to encapsulate the transplanted islets via 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) reaction, and successful conjugation was confirmed by Nuclear Magnetic Resonance H1 spectrum. The best VEGF concentration (100 ng/ml) was determined by the combined studies of the mechanical property and endothelial cell growth assay. In vivo study, conjugated VEGF on alginate exhibited sustained promoting angiogenesis property after subcutaneous transplantation by histology study and islets encapsulated in this material achieved long term therapeutic effect (up to 50 days) in the diabetic mice model. In conclusion, this study establishes a simple biomaterial strategy for islet transplantation to enhance islet survival and function, which could be a feasible therapeutic alternative for type 1 diabetes. - Highlights: • We synthesized VEGF-conjugated alginate material to encapsulate the transplanted islets. • The biomaterials improve islet engraftment and function due to angiogenesis. • The biomaterials could be a strong support for cell therapy with islet transplantation in type 1 diabetes.

  6. VEGF-conjugated alginate hydrogel prompt angiogenesis and improve pancreatic islet engraftment and function in type 1 diabetes

    International Nuclear Information System (INIS)

    Yin, Nina; Han, Yongming; Xu, Hanlin; Gao, Yisen; Yi, Tao; Yao, Jiale; Dong, Li; Cheng, Dejun; Chen, Zebin

    2016-01-01

    Type 1 diabetes was a life-long disease that affected numerous people around the world. Insulin therapy has its limitations that may involve hyperglycemia and heavy burden of patient by repeated dose. Islet transplantation emerged as a promising approach to reach periodical reverse of diabetes, however, transplanted islets suffer from foreign body reaction and lack of nutrition and oxygen supply, especially in the blood-vessel-shortage subcutaneous site which was preferred by patient and surgeon. In this study, we designed and synthesized a vascular endothelial growth factor (VEGF) conjugated alginate material to encapsulate the transplanted islets via 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) reaction, and successful conjugation was confirmed by Nuclear Magnetic Resonance H1 spectrum. The best VEGF concentration (100 ng/ml) was determined by the combined studies of the mechanical property and endothelial cell growth assay. In vivo study, conjugated VEGF on alginate exhibited sustained promoting angiogenesis property after subcutaneous transplantation by histology study and islets encapsulated in this material achieved long term therapeutic effect (up to 50 days) in the diabetic mice model. In conclusion, this study establishes a simple biomaterial strategy for islet transplantation to enhance islet survival and function, which could be a feasible therapeutic alternative for type 1 diabetes. - Highlights: • We synthesized VEGF-conjugated alginate material to encapsulate the transplanted islets. • The biomaterials improve islet engraftment and function due to angiogenesis. • The biomaterials could be a strong support for cell therapy with islet transplantation in type 1 diabetes.

  7. The intraportal injection model: A practical animal model for hepatic metastases and tumor cell dissemination in human colon cancer

    International Nuclear Information System (INIS)

    Thalheimer, Andreas; Waaga-Gasser, Ana M; Otto, Christoph; Bueter, Marco; Illert, Bertram; Gattenlohner, Stefan; Gasser, Martin; Meyer, Detlef; Fein, Martin; Germer, Christoph T

    2009-01-01

    The development of new therapeutic strategies for treatment of metastasized colorectal carcinoma requires biologically relevant and adequate animal models that generate both reproducible metastasis and the dissemination of tumor cells in the form of so-called minimal residual disease (MRD), an expression of the systemic character of neoplastic disease. We injected immunoincompetent nude mice intraportally with different numbers (1 × 10 5 , 1 × 10 6 and 5 × 10 6 cells) of the human colon carcinoma cell lines HT-29 and SW-620 and investigated by histological studies and CK-20 RT-PCR the occurrence of hematogenous metastases and the dissemination of human tumor cells in bone marrow. Only the injection of 1 × 10 6 cells of each colon carcinoma cell line produced acceptable perioperative mortality with reproducible induction of hepatic metastases in up to 89% of all animals. The injection of 1 × 10 6 cells also generated tumor cell dissemination in the bone marrow in up to 63% of animals with hepatic metastases. The present intraportal injection model in immunoincompetent nude mice represents a biologically relevant and adequate animal model for the induction of both reproducible hepatic metastasis and tumor cell dissemination in the bone marrow as a sign of MRD

  8. Improvement of islet function in a bioartificial pancreas by enhanced oxygen supply and growth hormone releasing hormone agonist

    NARCIS (Netherlands)

    Ludwig, Barbara; Rotem, Avi; Schmid, Janine; Weir, Gordon C.; Colton, Clark K.; Brendel, Mathias D.; Neufeld, Tova; Block, Norman L.; Yavriyants, Karina; Steffen, Anja; Ludwig, Stefan; Chavakis, Triantafyllos; Reichel, Andreas; Azarov, Dimitri; Zimermann, Baruch; Maimon, Shiri; Balyura, Mariya; Rozenshtein, Tania; Shabtay, Noa; Vardi, Pnina; Bloch, Konstantin; de Vos, Paul; Schally, Andrew V.; Bornstein, Stefan R.; Barkai, Uriel

    2012-01-01

    Islet transplantation is a feasible therapeutic alternative for metabolically labile patients with type 1 diabetes. The primary therapeutic target is stable glycemic control and prevention of complications associated with diabetes by reconstitution of endogenous insulin secretion. However, critical

  9. 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.

  10. 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.

  11. Intraocular in vivo imaging of pancreatic islet cell physiology/pathology

    Directory of Open Access Journals (Sweden)

    Ingo B. Leibiger

    2017-09-01

    Major conclusions: Data provided by us and others demonstrate the high versatility of this imaging platform. The use of ‘reporter islets’ engrafted in the eye, reporting on the status of in situ endogenous islets in the pancreas of the same animal, allows the identification of key-events in the development and progression of diabetes. This will not only serve as a versatile research tool but will also lay the foundation for a personalized medicine approach and will serve as a screening platform for new drugs and/or treatment protocols. ‘Metabolic’ islet transplantation, in which islets engrafted in the eye replace the endogenous beta cells, will allow for the establishment of islet-specific transgenic models and ‘humanized’ mouse models as well as serving as the basis for a new clinical transplantation site for the cure of diabetes.

  12. Mitigating hypoxic stress on pancreatic islets via in situ oxygen generating biomaterial.

    Science.gov (United States)

    Coronel, Maria M; Geusz, Ryan; Stabler, Cherie L

    2017-06-01

    A major obstacle in the survival and efficacy of tissue engineered transplants is inadequate oxygenation, whereby unsupportive oxygen tensions result in significant cellular dysfunction and death within the implant. In a previous report, we developed an innovative oxygen generating biomaterial, termed OxySite, to provide supportive in situ oxygenation to cells and prevent hypoxia-induced damage. Herein, we explored the capacity of this biomaterial to mitigate hypoxic stress in both rat and nonhuman primate pancreatic islets by decreasing cell death, supporting metabolic activity, sustaining aerobic metabolism, preserving glucose responsiveness, and decreasing the generation of inflammatory cytokines. Further, the impact of supplemental oxygenation on in vivo cell function was explored by the transplantation of islets previously co-cultured with OxySite into a diabetic rat model. Transplant outcomes revealed significant improvement in graft efficacy for OxySite-treated islets, when transplanted within an extrahepatic site. These results demonstrate the potency of the OxySite material to mitigate activation of detrimental hypoxia-induced pathways in islets during culture and highlights the importance of in situ oxygenation on resulting islet transplant outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Comparison of modified Celsior solution and M-kyoto solution for pancreas preservation in human islet isolation.

    Science.gov (United States)

    Noguchi, Hirofumi; Naziruddin, Bashoo; Onaca, Nicholas; Jackson, Andrew; Shimoda, Masayuki; Ikemoto, Tetsuya; Fujita, Yasutaka; Kobayashi, Naoya; Levy, Marlon F; Matsumoto, Shinichi

    2010-01-01

    Since the successful demonstration of the Edmonton protocol, islet transplantation has advanced significantly on several fronts, including improved pancreas preservation systems. In this study, we evaluated two different types of organ preservation solutions for human islet isolation. Modified Celsior (Celsior solution with hydroxyethyl starch and nafamostat mesilate; HNC) solution and modified Kyoto (MK) solution were compared for pancreas preservation prior to islet isolation. Islet yield after purification was significantly higher in the MK group than in the HNC group (MK = 6186 ± 985 IE/g; HNC = 3091 ± 344 IE/g). The HNC group had a longer phase I period (digestion time), a higher volume of undigested tissue, and a higher percentage of embedded islets, suggesting that the solution may inhibit collagenase. However, there was no significant difference in ATP content in the pancreata or in the attainability of posttransplant normoglycemia in diabetic nude mice between the two groups, suggesting that the quality of islets was similar among the two groups. In conclusion, MK solution is better for pancreas preservation before islet isolation than HNC solution due to the higher percentage of islets that can be isolated from the donor pancreas. MK solution should be the solution of choice among the commercially available solutions for pancreatic islet isolation leading to transplantation.

  14. Unmethylated Insulin DNA Is Elevated After Total Pancreatectomy With Islet Autotransplantation: Assessment of a Novel Beta Cell Marker.

    Science.gov (United States)

    Bellin, M D; Clark, P; Usmani-Brown, S; Dunn, T B; Beilman, G J; Chinnakotla, S; Pruett, T L; Ptacek, P; Hering, B J; Wang, Z; Gilmore, T; Wilhelm, J J; Hodges, J S; Moran, A; Herold, K C

    2017-04-01

    Beta cell death may occur both after islet isolation and during infusion back into recipients undergoing total pancreatectomy with islet autotransplantation (TPIAT) for chronic pancreatitis. We measured the novel beta cell death marker unmethylated insulin (INS) DNA in TPIAT recipients before and immediately after islet infusion (n = 21) and again 90 days after TPIAT, concurrent with metabolic functional assessments (n = 25). As expected, INS DNA decreased after pancreatectomy (p = 0.0002). All TPIAT recipients had an elevated unmethylated INS DNA ratio in the first hours following islet infusion. In four samples (three patients), INS DNA was also assessed immediately after islet isolation and again before islet infusion to assess the impact of the isolation process: Unmethylated and methylated INS DNA fractions both increased over this interval, suggesting death of beta cells and exocrine tissue before islet infusion. Higher glucose excursion with mixed-meal tolerance testing was associated with persistently elevated INS DNA at day 90. In conclusion, we observed universal early elevations in the beta cell death marker INS DNA after TPIAT, with pronounced elevations in the islet supernatant before infusion, likely reflecting beta cell death induced by islet isolation. Persistent posttransplant elevation of INS DNA predicted greater hyperglycemia at 90 days. © Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.

  15. Fetal rat pancreas transplantation in BB rats: immunohistochemical and functional evaluation.

    Science.gov (United States)

    Yderstraede, K B; Starklint, H; Steinbruchel, D; Jørgensen, T W; Gotfredsen, C F

    1993-01-01

    Spontaneously diabetic BB/Wor rats received either a syngeneic fetal pancreas transplant or adult islets. In the former, 4-8 fetal pancreases were transplanted, and in the latter, 3-5000 islets. Transplantation was performed by transferring a blood clot containing the pancreases or islets to the renal subcapsular space. Insulin therapy was undertaken postoperatively, except in one experiment with adult islets. Of the fetal pancreas transplanted BB rats, 52% became normoglycaemic, and 21% remained so throughout an observation period of 10 months. Nephrectomy caused a prompt return of diabetes. The histological appearance of the grafts transplanted to the diabetic animals closely resembled that of grafts transplanted to normal rats in a parallel series. For comparison a group of BB rats received a syngeneic transplant of isolated adult islets from WF rats or BBW rats. Following adult islet transplantation, 5 out of 6 animals became hyperglycaemic after a median of 20.5 days when no insulin was given post-transplantation. Four out of 5 animals became hyperglycaemic after a median of 23 days when supportive insulin therapy was administered after the transplantation. The results indicate that recurrent diabetes is not inevitable following syngeneic fetal pancreas transplantation to spontaneously diabetic BB rats. Recurrent diabetes was only occasionally associated with mononuclear cell infiltration. Transplanted tissue was well-preserved and vascularized; mega-islets were a constant finding.

  16. Cotransplantation of Mesenchymal Stem Cells and Immature Dendritic Cells Potentiates the Blood Glucose Control of Islet Allografts

    Directory of Open Access Journals (Sweden)

    Guanghui Long

    2017-01-01

    Full Text Available Background. Transplantation of islets is a promising alternative to treat type 1 diabetes (T1D, but graft rejection is the major obstacle to its application in clinical practice. We evaluated the effects of mesenchymal stem cells (MSCs and immature dendritic cells (imDCs on islet transplantation in diabetic model. Methods. The streptozotocin T1D model was established in BABL/c mice. Rat islets were isolated and identified with dithizone (DTZ staining. MSCs and imDCs were isolated from bone marrow of syngenic mice. Islets, alone or along with MSCs and/or imDCs, were transplanted to the left kidney capsule of diabetic mice. The blood glucose levels and glycosylated hemoglobin levels after transplantation were monitored. Results. Cotransplantation significantly decreased blood glucose and glycosylated hemoglobin levels in the diabetes mice. Transplantation of 200 islets + 2 × 105 MSCs + 2 × 105 imDCs could not only restore normal blood glucose levels, but also significantly prolong graft survival for 12.6±3.48 days. Conclusions. Cotransplantation of allogenic islets with imDCs and/or MSCs can significantly promote graft survival, reverse hyperglycemia, and effectively control the glycosylated hemoglobin levels.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  19. The Purification Method Using Iodixanol (Optiprep)-Based Density Gradient Significantly Reduces Cytokine/Chemokine Production from Human Islet Preparations, Leading to Prolong β-Cell Survival During Culture

    Science.gov (United States)

    Mita, Atsuyoshi; Ricordi, Camillo; Miki, Atsushi; Barker, Scott; Khan, Aisha; Alvarez, Alejandro; Hashikura, Yasuhiko; Miyagawa, Shin-ichi; Ichii, Hirohito

    2009-01-01

    Improved islet isolation has still been important to obtain adequate islet numbers for islet transplantation. Although Ficol-based density gradient is widely used for purification in most islet processing centers, OptiPrep-based density gradient is recently used in the limited centers and their clinical outcomes are excellent. Cytokine/chemokine production from islet preparations for transplantation widely varies. Some cytokines/chemokines have been reported to cause apoptosis in human islet preparations after isolation. Reducing cytokine/chemokine production is a key to improve islet numbers after isolation and islet transplantation outcome. The aim of current study is to investigate the variability of pro-inflammatory cytokine/chemokine production from islet preparations purified by different density gradient. After digestion of human pancreata, pre-purification digests were devided into two groups and purified using semi-automated cell processor with Ficoll-based and OptiPrep-based density gradient. Islet preparations were cultured for 2 days and assessed regarding islet cell viability (FDA/PI), fractional β-cell viability and β-cell content. Cytokine/chemokine production from islet preparations was also examined. After purification, purity, post-purification IEQ and islet recovery rate were comparable between two groups. Although FDA/PI and fractional β-cell viability showed no significant differences, β-cell survival during culture significantly increased in OptiPrep-based density gradient group when compared to Ficoll-based density gradient group. TNF-α, IL-1β, IFN-γ, IL-6 and MIP-1β production from OptiPrep-based density gradient group significantly decreased. OptiPrep-based density gradient can reduce cytokine-production when compared to Ficoll-based density gradient, resulting in improvement of quantity of β-cell mass. Cytokine profiling could spot new light on assessment of islet preparations before transplantation. PMID:19249543

  20. Combined strategy of endothelial cells coating, Sertoli cells coculture and infusion improves vascularization and rejection protection of islet graft.

    Directory of Open Access Journals (Sweden)

    Yang Li

    Full Text Available Improving islet graft revascularization and inhibiting rejection become crucial tasks for prolonging islet graft survival. Endothelial cells (ECs are the basis of islet vascularization and Sertoli cells (SCs have the talent to provide nutritional support and exert immunosuppressive effects. We construct a combined strategy of ECs coating in the presence of nutritious and immune factors supplied by SCs in a co-culture system to investigate the effect of vascularization and rejection inhibition for islet graft. In vivo, the combined strategy improved the survival and vascularization as well as inhibited lymphocytes and inflammatory cytokines. In vitro, we found the combinatorial strategy improved the function of islets and the effect of ECs-coating on islets. Combined strategy treated islets revealed higher levels of anti-apoptotic signal molecules (Bcl-2 and HSP-32, survival and function related molecules (PDX-1, Ki-67, ERK1/2 and Akt and demonstrated increased vascular endothelial growth factor receptor 2 (KDR and angiogenesis signal molecules (FAk and PLC-γ. SCs effectively inhibited the activation of lymphocyte stimulated by islets and ECs. Predominantly immunosuppressive cytokines could be detected in culture supernatants of the SCs coculture group. These results suggest that ECs-coating and Sertoli cells co-culture or infusion synergistically enhance islet survival and function after transplantation.

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

    Science.gov (United States)

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

    2016-07-03

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

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  3. Silicon nanopore membrane (SNM) for islet encapsulation and immunoisolation under convective transport

    Science.gov (United States)

    Song, Shang; Faleo, Gaetano; Yeung, Raymond; Kant, Rishi; Posselt, Andrew M; Desai, Tejal A; Tang, Qizhi; Roy, Shuvo

    2016-01-01

    Problems associated with islet transplantation for Type 1 Diabetes (T1D) such as shortage of donor cells, use of immunosuppressive drugs remain as major challenges. Immune isolation using encapsulation may circumvent the use of immunosuppressants and prolong the longevity of transplanted islets. The encapsulating membrane must block the passage of host’s immune components while providing sufficient exchange of glucose, insulin and other small molecules. We report the development and characterization of a new generation of semipermeable ultrafiltration membrane, the silicon nanopore membrane (SNM), designed with approximately 7 nm-wide slit-pores to provide middle molecule selectivity by limiting passage of pro-inflammatory cytokines. Moreover, the use of convective transport with a pressure differential across the SNM overcomes the mass transfer limitations associated with diffusion through nanometer-scale pores. The SNM exhibited a hydraulic permeability of 130 ml/hr/m2/mmHg, which is more than 3 fold greater than existing polymer membranes. Analysis of sieving coefficients revealed 80% reduction in cytokines passage through SNM under convective transport. SNM protected encapsulated islets from infiltrating cytokines and retained islet viability over 6 hours and remained responsive to changes in glucose levels unlike non-encapsulated controls. Together, these data demonstrate the novel membrane exhibiting unprecedented hydraulic permeability and immune-protection for islet transplantation therapy. PMID:27009429

  4. The effect of Nrf2 pathway activation on human pancreatic islet cells.

    Directory of Open Access Journals (Sweden)

    Yuichi Masuda

    Full Text Available Pancreatic islets are known to contain low level of antioxidants that renders them vulnerable to oxidative stress. Nrf2 is the master regulator of numerous genes, encoding antioxidant, detoxifying, and cytoprotective molecules. Activation of Nrf2 pathway induces up-regulation of numerous genes encoding antioxidant and phase II detoxifying enzymes and related proteins. However, little is known regarding the role of this pathway in human islet cells. The aim was to investigate the effect of Nrf2 activator (dh404, CDDO-9,11-dihydro-trifluoroethyl amide on human islet cells.Human islets were obtained from cadaveric donors. After dh404 treatment, Nrf2 translocation, mRNA expression, and protein abundance of its key target gene products were examined. The proportion of dh404-treated or non-treated viable islet beta cells was analyzed using flowcytemetry. The cytoprotective effects against oxidative stress and production of inflammatory mediators, and in vivo islet function after transplantation were determined.Nrf2 nuclear translocation was confirmed by con-focal microscope within 2 hours after treatment, which was associated with a dose-dependent increase in mRNA expression of anti-oxidants, including NQO1, HO-1, and GCLC. Enhanced HO-1 expression in dh404 treated islets was confirmed by Western Blot assay. Islet function after transplantation (2000 IEQ/mouse to diabetic nude mice was not affected with or without dh404 treatment. After induction of oxidative stress with hydrogen peroxide (200 μM the proportion of dh404-treated viable islet cells was significantly higher in the dh404-treated than untreated islets (74% vs.57%; P<0.05. Dh404 significantly decreased production of cytokines/chemokines including IL-1β, IL-6, IFN-γ and MCP-1.Treatment of human pancreatic islets with the potent synthetic Nrf2 activator, dh404, significantly increased expression of the key anti-oxidants enzymes, decreased inflammatory mediators in islets and conferred

  5. Catheter-directed Intraportal Delivery of Endothelial Cell Therapy for Liver Regeneration: A Feasibility Study in a Large-Animal Model of Cirrhosis.

    Science.gov (United States)

    Lee, Kyungmouk Steve; Santagostino, Sara F; Li, David; Ramjit, Amit; Serrano, Kenneth; Ginsberg, Michael D; Ding, Bi-Sen; Rafii, Shahin; Madoff, David C

    2017-10-01

    Purpose To demonstrate the feasibility of imaging-guided catheter-directed delivery of endothelial cell therapy in a porcine model of cirrhosis for liver regeneration. Materials and Methods After approval from the institutional animal care and use committee, autologous liver endothelial cells were grown from core hepatic specimens from swine. Cirrhosis was induced in swine by means of transcatheter infusion of ethanol and iodized oil into the hepatic artery. Three weeks after induction of cirrhosis, the swine were randomly assigned to receive autologous cell therapy (endothelial cells, n = 4) or control treatment (phosphate-buffered saline, n = 4) by means of imaging-guided transhepatic intraportal catheterization. Fluorescence-activated cell sorting analysis was performed on biopsy samples 1 hour after therapy. Three weeks after intraportal delivery of endothelial cells, the swine were euthanized and the explanted liver underwent quantitative pathologic examination. Statistical analysis was performed with an unpaired t test by using unequal variance. Results Liver endothelial cells were successfully isolated, cultured, and expanded from eight 20-mm, 18-gauge hepatic core samples to 50 × 10 6 autologous cells per pig. Intraportal delivery of endothelial cell therapy or saline was technically successful in all eight swine, with no complications. Endothelial cells were present in the liver for a minimum of 1 hour after intraportal infusion. Swine treated with endothelial cell therapy showed mean levels of surrogate markers of hepatobiliary injury that were consistent with decreases in hepatic fibrosis and biliary ductal damage relative to the control animals, although statistical significance was not met in this pilot study: The mean percentage of positive pixels at Masson trichrome staining was 7.28% vs 5.57%, respectively (P = .20), the mean proliferation index with cytokeratin wide-spectrum was 2.55 vs 1.13 (P = .06), and the mean proliferation index with Ki67

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Fang Xiao

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

  8. Use of additives, scaffolds and extracellular matrix components for improvement of human pancreatic islet outcomes in vitro: A systematic review.

    Science.gov (United States)

    Lemos, Natália Emerim; de Almeida Brondani, Letícia; Dieter, Cristine; Rheinheimer, Jakeline; Bouças, Ana Paula; Bauermann Leitão, Cristiane; Crispim, Daisy; Bauer, Andrea Carla

    2017-09-03

    Pancreatic islet transplantation is an established treatment to restore insulin independence in type 1 diabetic patients. Its success rates have increased lately based on improvements in immunosuppressive therapies and on islet isolation and culture. It is known that the quality and quantity of viable transplanted islets are crucial for the achievement of insulin independence and some studies have shown that a significant number of islets are lost during culture time. Thus, in an effort to improve islet yield during culture period, researchers have tested a variety of additives in culture media as well as alternative culture devices, such as scaffolds. However, due to the use of different categories of additives or devices, it is difficult to draw a conclusion on the benefits of these strategies. Therefore, the aim of this systematic review was to summarize the results of studies that described the use of medium additives, scaffolds or extracellular matrix (ECM) components during human pancreatic islets culture. PubMed and Embase repositories were searched. Of 5083 articles retrieved, a total of 37 articles fulfilled the eligibility criteria and were included in the review. After data extraction, articles were grouped as follows: 1) "antiapoptotic/anti-inflammatory/antioxidant," 2) "hormone," 3) "sulphonylureas," 4) "serum supplements," and 5) "scaffolds or ECM components." The effects of the reviewed additives, ECM or scaffolds on islet viability, apoptosis and function (glucose-stimulated insulin secretion - GSIS) were heterogeneous, making any major conclusion hard to sustain. Overall, some "antiapoptotic/anti-inflammatory/antioxidant" additives decreased apoptosis and improved GSIS. Moreover, islet culture with ECM components or scaffolds increased GSIS. More studies are needed to define the real impact of these strategies in improving islet transplantation outcomes.

  9. A hybrid of cells and pancreatic islets toward a new bioartificial pancreas

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    Yuji Teramura

    2016-03-01

    Full Text Available Cell surface engineering using single-stranded DNA–poly(ethylene glycol-conjugated phospholipid (ssDNA–PEG-lipid is useful for inducing cell–cell attachment two and three dimensionally. In this review, we summarize our recent techniques for cell surface engineering and their applications to islet transplantation. Because any DNA sequence can be immobilized onto the cell surface by hydrophobic interactions between ssDNA–PEG-lipid and the cellular membrane without impairing cell function, a cell–cell hybrid can be formed through the DNA hybridization. With this technique, it would be possible to create three-dimensional hybrid structures of pancreatic islets coated with various accessory cells, such as patients’ own cells, mesenchymal and adipose-derived stem cells, endothelial progenitor cells, neural crest stem cells or regulatory T cells, which might significantly improve the outcome of islet transplantation in diabetic patients.

  10. 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.

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

    Science.gov (United States)

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

    2005-10-01

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

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

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  13. Immunological Challenges Facing Translation of Alginate Encapsulated Porcine Islet Xenotransplantation to Human Clinical Trials

    NARCIS (Netherlands)

    Krishnan, Rahul; Ko, David; Foster, Clarence E; Liu, Wendy; Smink, A M; de Haan, Bart; De Vos, Paul; Lakey, Jonathan R T; Opara, Ammanuel C.

    2017-01-01

    Transplantation of alginate-encapsulated islets has the potential to treat patients suffering from type I diabetes, a condition characterized by an autoimmune attack against insulin-secreting beta cells. However, there are multiple immunological challenges associated with this procedure, all of

  14. Treatment with Tacrolimus and Sirolimus Reveals No Additional Adverse Effects on Human Islets In Vitro Compared to Each Drug Alone but They Are Reduced by Adding Glucocorticoids.

    Science.gov (United States)

    Kloster-Jensen, Kristine; Sahraoui, Afaf; Vethe, Nils Tore; Korsgren, Olle; Bergan, Stein; Foss, Aksel; Scholz, Hanne

    2016-01-01

    Tacrolimus and sirolimus are important immunosuppressive drugs used in human islet transplantation; however, they are linked to detrimental effects on islets and reduction of long-term graft function. Few studies investigate the direct effects of these drugs combined in parallel with single drug exposure. Human islets were treated with or without tacrolimus (30 μg/L), sirolimus (30 μg/L), or a combination thereof for 24 hrs. Islet function as well as apoptosis was assessed by glucose-stimulated insulin secretion (GSIS) and Cell Death ELISA. Proinflammatory cytokines were analysed by qRT-PCR and Bio-Plex. Islets exposed to the combination of sirolimus and tacrolimus were treated with or without methylprednisolone (1000 μg/L) and the expression of the proinflammatory cytokines was investigated. We found the following: (i) No additive reduction in function and viability in islets existed when tacrolimus and sirolimus were combined compared to the single drug. (ii) Increased expression of proinflammatory cytokines mRNA and protein levels in islets took place. (iii) Methylprednisolone significantly decreased the proinflammatory response in islets induced by the drug combination. Although human islets are prone to direct toxic effect of tacrolimus and sirolimus, we found no additive effects of the drug combination. Short-term exposure of glucocorticoids could effectively reduce the proinflammatory response in human islets induced by the combination of tacrolimus and sirolimus.

  15. Experience of islet isolation without neutral protease supplementation.

    Science.gov (United States)

    Kin, Tatsuya; O'Gorman, Doug; Senior, Peter; Shapiro, A M James

    2010-01-01

    We have reported improved islet isolation outcomes using a new digestion protocol where the pancreas is perfused only with collagenase, and neutral protease (NP) is administered during the digestion phase. Since the inception of this protocol, we have had some cases where administration of NP was not required. Our new protocol was utilized in 94 islet isolations. The timing of adding NP was dependent on the progression of digestion but in 10 cases the progression was rapid and most islets in the assessment samples were free from the exocrine tissue. As a result NP was not added at all for these isolations (no-NP group). In the remaining 84 isolations, NP was added during digestion phase (control group). Pancreata in the each group were digested with a similar collagenase dose. Digestion time was shorter in the no-NP (15.0±1.8 vs 19.5±0.6 min, P=0.004). At post-digestion, the no-NP had fewer trapped islets (10.9±2.8 vs 28.1±2.4%, P=0.009). Post-purification islet yield was similar (355±45 x10 ( 3) vs 318±17 x10 ( 3) IE, P=0.29). Five preparations in the no-NP were used for clinical transplantation, leading to a 64.3±15.2% reduction in insulin usage. Interestingly, cold ischemia time was longer in the no-NP (10.3±0.9 vs 7.9±0.4 h, P=0.04). One particular collagenase lot having the highest NP activity contamination was used in 7 isolations in the no-NP. Our experience indicates that supplementation of collagenase with NP is not always necessary for effective isolation. Cold ischemia time and NP contamination should be evaluated for optimal NP dosage.

  16. Long-term normalization of diabetes mellitus after xenotransplantation of fetal pancreatic islet cells into the blood stream without immunosuppresive therapy.

    Science.gov (United States)

    Prochorov, A V; Tretjak, S I; Roudenok, V V; Goranov, V A

    2004-11-01

    The article presents a new method of surgical treatment of experimental diabetes mellitus in a rabbit to dog model. Rabbit islet cells, which had been macroencapsulated into a microporous polyamide, were implanted into the dog aorta without immunosuppressive therapy. Euglycemia was reached at 4 to 5 days and persisted for 12 months. Morphological and immunohistochemical investigations showed long-term preservation of islet cell viability, absence of graft rejection, and formation of a biological artificial pancreas in the capsule at 6 months after transplantation. Up to 60% of transplanted cells were still viable 12 months later. The major factor contributing to preservation of islet cells is neo-angiogenesis, which develops during the first weeks after transplantation. Double immune isolation of islet cells by macroencapsulation with implantation into the blood stream allows the use of either xenotransplantation or allotransplantation.

  17. In Vitro Proliferation of Porcine Pancreatic Islet Cells for β-Cell Therapy Applications

    Directory of Open Access Journals (Sweden)

    Guoguang Niu

    2016-01-01

    Full Text Available β-Cell replacement through transplantation is the only curative treatment to establish a long-term stable euglycemia in diabetic patients. Owing to the shortage of donor tissue, attempts are being made to develop alternative sources of insulin-secreting cells. Stem cells differentiation and reprograming as well as isolating pancreatic progenitors from different sources are some examples; however, no approach has yet yielded a clinically relevant solution. Dissociated islet cells that are cultured in cell numbers by in vitro proliferation provide a promising platform for redifferentiation towards β-cells phenotype. In this study, we cultured islet-derived cells in vitro and examined the expression of β-cell genes during the proliferation. Islets were isolated from porcine pancreases and enzymatically digested to dissociate the component cells. The cells proliferated well in tissue culture plates and were subcultured for no more than 5 passages. Only 10% of insulin expression, as measured by PCR, was preserved in each passage. High glucose media enhanced insulin expression by about 4–18 fold, suggesting a glucose-dependent effect in the proliferated islet-derived cells. The islet-derived cells also expressed other pancreatic genes such as Pdx1, NeuroD, glucagon, and somatostatin. Taken together, these results indicate that pancreatic islet-derived cells, proliferated in vitro, retained the expression capacity for key pancreatic genes, thus suggesting that the cells may be redifferentiated into insulin-secreting β-like cells.

  18. Islet-like cell aggregates generated from human adipose tissue derived stem cells ameliorate experimental diabetes in mice.

    Directory of Open Access Journals (Sweden)

    Vikash Chandra

    Full Text Available BACKGROUND: Type 1 Diabetes Mellitus is caused by auto immune destruction of insulin producing beta cells in the pancreas. Currently available treatments include transplantation of isolated islets from donor pancreas to the patient. However, this method is limited by inadequate means of immuno-suppression to prevent islet rejection and importantly, limited supply of islets for transplantation. Autologous adult stem cells are now considered for cell replacement therapy in diabetes as it has the potential to generate neo-islets which are genetically part of the treated individual. Adopting methods of islet encapsulation in immuno-isolatory devices would eliminate the need for immuno-suppressants. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we explore the potential of human adipose tissue derived adult stem cells (h-ASCs to differentiate into functional islet like cell aggregates (ICAs. Our stage specific differentiation protocol permit the conversion of mesodermic h-ASCs to definitive endoderm (Hnf3β, TCF2 and Sox17 and to PDX1, Ngn3, NeuroD, Pax4 positive pancreatic endoderm which further matures in vitro to secrete insulin. These ICAs are shown to produce human C-peptide in a glucose dependent manner exhibiting in-vitro functionality. Transplantation of mature ICAs, packed in immuno-isolatory biocompatible capsules to STZ induced diabetic mice restored near normoglycemia within 3-4 weeks. The detection of human C-peptide, 1155±165 pM in blood serum of experimental mice demonstrate the efficacy of our differentiation approach. CONCLUSIONS: h-ASC is an ideal population of personal stem cells for cell replacement therapy, given that they are abundant, easily available and autologous in origin. Our findings present evidence that h-ASCs could be induced to differentiate into physiologically competent functional islet like cell aggregates, which may provide as a source of alternative islets for cell replacement therapy in type 1 diabetes.

  19. Xenotransplantation of porcine neonatal islets of Langerhans and Sertoli cells: a 4-year study.

    Science.gov (United States)

    Valdés-González, Rafael A; Dorantes, Luis M; Garibay, G Nayely; Bracho-Blanchet, Eduardo; Mendez, Armando J; Dávila-Pérez, Roberto; Elliott, Robert B; Terán, Luis; White, David J G

    2005-09-01

    Porcine islets of Langerhans for xenotransplantation into humans have been proposed as a solution to the shortage of human donors. Rejection is one of the main constraints. This study presents the results of a clinical trial using a novel method for transplanting and immunoprotecting porcine islets in type 1 diabetic patients. A 4-year follow up of a clinical trial involving 12 patients, with no immunosuppressive drugs at any point. Eleven age matched untransplanted diabetics served as controls. We have developed a procedure for protecting neonatal porcine islets by combining them with Sertoli cells and placing them in a novel subcutaneous autologous collagen-covered device. In the patients in the treatment group, no complications arose and no porcine endogenous retrovirus infection was detected. Half of the patients showed a significant reduction in insulin requirements compared with both their pre transplant levels and controls, and this reduction was maintained for up to 4 years. Two patients became insulin-independent for several months. Porcine insulin was detected in three patients' sera following glucose stimulation up to 4 years post transplant. Three years post transplant, one of four devices was removed from four patients, and the presence of insulin-positive cells in the transplant was demonstrated by immunohistology in all 4 patients. Long-term cell survival with concurrent positive effects on metabolic control are possible by this technique.

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

    Science.gov (United States)

    Buchwald, Peter

    2009-04-16

    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. 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. 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 microm 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. 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 non-vascularised islet and can lead to considerable cell

  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. Immune responses to an encapsulated allogeneic islet β-cell line in diabetic NOD mice

    International Nuclear Information System (INIS)

    Black, Sasha P.; Constantinidis, Ioannis; Cui, Hong; Tucker-Burden, Carol; Weber, Collin J.; Safley, Susan A.

    2006-01-01

    Our goal is to develop effective islet grafts for treating type 1 diabetes. Since human islets are scarce, we evaluated the efficacy of a microencapsulated insulin-secreting conditionally transformed allogeneic β-cell line (βTC-tet) in non-obese diabetic mice treated with tetracycline to inhibit cell growth. Relatively low serum levels of tetracycline controlled proliferation of βTC-tet cells without inhibiting effective control of hyperglycemia in recipients. There was no significant host cellular reaction to the allografts or host cell adherence to microcapsules, and host cytokine levels were similar to those of sham-operated controls. We conclude that encapsulated allogeneic β-cell lines may be clinically relevant, because they effectively restore euglycemia and do not elicit a strong cellular immune response following transplantation. To our knowledge, this is First extensive characterization of the kinetics of host cellular and cytokine responses to an encapsulated islet cell line in an animal model of type 1 diabetes

  3. The dissociation of tumor-induced weight loss from hypoglycemia in a transplantable pluripotent rat islet tumor results in the segregation of stable alpha- and beta-cell tumor phenotypes

    DEFF Research Database (Denmark)

    Madsen, O D; Karlsen, C; Nielsen, E

    1993-01-01

    that of starved rats until death results from cachexia. After tumor resection, animals immediately resume normal feeding behavior. Comparative studies of hormone release and mRNA content in anorectic lines, MSL-G-AN and NHI-5B-AN, vs. those in the insulinoma line, MSL-G2-IN, revealed selective glucagon gene...... in animals carrying tumor necrosis factor-producing experimental tumors....... markers. By selective transplantation, it was possible to segregate stable anorectic normoglycemic tumor lines, MSL-G-AN and NHI-5B-AN, from both clones. These tumors cause an abrupt onset of anorexia when they reach a size of 400-500 mg (

  4. First update of the International Xenotransplantation Association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes--Chapter 3: Porcine islet product manufacturing and release testing criteria.

    Science.gov (United States)

    Rayat, Gina R; Gazda, Lawrence S; Hawthorne, Wayne J; Hering, Bernhard J; Hosking, Peter; Matsumoto, Shinichi; Rajotte, Ray V

    2016-01-01

    sterility culture results are positive. In terms of the characterization of porcine islet products and product release criteria, the information on the porcine islet products should be acquired from a sample of the final product to be used for transplantation and must include the morphology of the islets, specific identity, purity, viability, and potency of the product. In addition, information on the quantity of the islet products should also be provided in a standardized fashion and this should be in terms of islet equivalents and/or cell numbers. The current consensus was created to provide guidelines that manufacturing facilities may find helpful in the manufacture of and the release criteria for porcine islet products including encapsulated islets and combined islet products. Our intent with the above recommendations is to provide a framework for individual porcine islet manufacturing facilities to ensure a high level of safety for the initiation of Phase 1/2 clinical trials on porcine islet xenotransplantation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

    Science.gov (United States)

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

    2015-03-28

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

  6. Islets immunoisolation using encapsulation and PEGylation, simultaneously, as a novel design.

    Science.gov (United States)

    Nabavimanesh, Mohammad Mahdi; Hashemi-Najafabadi, Sameereh; Vasheghani-Farahani, Ebrahim

    2015-04-01

    The most important obstacle in islets transplantation for the treatment of diabetes is graft rejection by the host immune system. To solve this problem, immunosuppressive drugs should be used, but they may have several side effects. To overcome these problems, islets immunoisolation systems such as encapsulation and PEGylation have been developed. The aim of this study was to investigate the possibility of using encapsulation and PEGylation techniques simultaneously (as a novel design) for immunocamouflaging the islets of Langerhans. For this purpose, the attachment of poly-L-ornithine (PLO) onto the surface of alginate microcapsules and activated methoxy polyethylene glycol (mPEG) onto alginate-PLO microcapsules was verified by Fourier transform infrared analysis and scanning electron microscopy. Viability of the free and encapsulated islets up to the 7th day was approved by acridine orange (AO)/propidium iodide (PI). The obtained results from lymphocytes co-culturing with free and encapsulated islets (in different designs of microcapsules with one to three layers) showed that encapsulation generally reduces the immune response against the islets. However, the addition of PLO and mPEG as second and third layers to the surface of alginate microcapsules decreased interleukine-2 (IL-2) secretion against the islets more and more. Finally, two different activated mPEG, mPEG-succinimidyl carbonate (mPEG-SC) and mPEG-succinimidylvaleric acid (mPEG-SVA), used separately on the surface of microcapsules were investigated, and the results showed that IL-2 secretion was reduced 14.3% and 37.5% in comparison with the alginate-PLO microcapsules, respectively. On the other hand, mPEG-SVA was more effective than mPEG-SC, so it decreased IL-2 secretion 27.1% more than mPEG-SC. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  7. Human omentum fat-derived mesenchymal stem cells transdifferentiates into pancreatic islet-like cluster.

    Science.gov (United States)

    Dhanasekaran, M; Indumathi, S; Harikrishnan, R; Mishra, Rashmi; Lissa, R P; Rajkumar, J S; Sudarsanam, D

    2013-10-01

    Current protocols of islet cell transplantation for the treatment of diabetes mellitus have been hampered by islet availability and allograft rejection. Although bone marrow and subcutaneous adipose tissue stem cells feature their tissue repair efficacy, applicability of stem cells from various sources is being researched to develop a promising therapy for diabetes mellitus. Although omentum fat has emerged as an innovative source of stem cells, the dearth of researches confirming its transdifferentiation potential limits its applicability as a regenerative tool in diabetic therapy. Thus, this work is a maiden attempt to explore the colossal potency of omentum fat-derived stem cells on its lucrative differentiation ability. The plasticity of omentum fat stem cells was substantiated by transdifferentiation into pancreatic islet-like clusters, which was confirmed by dithizone staining and immunocytochemistry for insulin. It was also confirmed by the expression of pancreatic endocrine markers nestin and pancreatic duodenal homeobox 1 (Pdx 1) using Fluorescence-activated cell sorting (FACS), neurogenic 3, islet-1 transcription factor, paired box gene 4, Pdx 1 and insulin using quantitative real-time polymerase chain reaction and through insulin secretion assay. This study revealed the in vitro differentiation potency of omentum fat stem cells into pancreatic islet-like clusters. However, further research pursuits exploring its in vivo endocrine efficacy would make omentum fat stem cells a superior source for β-cell replacement therapy. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Repurposing Lesogaberan to Promote Human Islet Cell Survival and β-Cell Replication

    Directory of Open Access Journals (Sweden)

    Jide Tian

    2017-01-01

    Full Text Available The activation of β-cell’s A- and B-type gamma-aminobutyric acid receptors (GABAA-Rs and GABAB-Rs can promote their survival and replication, and the activation of α-cell GABAA-Rs promotes their conversion into β-cells. However, GABA and the most clinically applicable GABA-R ligands may be suboptimal for the long-term treatment of diabetes due to their pharmacological properties or potential side-effects on the central nervous system (CNS. Lesogaberan (AZD3355 is a peripherally restricted high-affinity GABAB-R-specific agonist, originally developed for the treatment of gastroesophageal reflux disease (GERD that appears to be safe for human use. This study tested the hypothesis that lesogaberan could be repurposed to promote human islet cell survival and β-cell replication. Treatment with lesogaberan significantly enhanced replication of human islet cells in vitro, which was abrogated by a GABAB-R antagonist. Immunohistochemical analysis of human islets that were grafted into immune-deficient mice revealed that oral treatment with lesogaberan promoted human β-cell replication and islet cell survival in vivo as effectively as GABA (which activates both GABAA-Rs and GABAB-Rs, perhaps because of its more favorable pharmacokinetics. Lesogaberan may be a promising drug candidate for clinical studies of diabetes intervention and islet transplantation.

  9. Immuno-isolation of pancreatic islet allografts using pegylated nanotherapy leads to long-term normoglycemia in full MHC mismatch recipient mice.

    Directory of Open Access Journals (Sweden)

    Huansheng Dong

    Full Text Available Two major hurdles need to be surmounted for cell therapy for diabetes: (i allo-immune rejection of grafted pancreatic islets, or stem/precursor cell-derived insulin-secreting cells; and (ii continuing auto-immunity against the diabetogenic endogenous target antigen. Nanotherapeutics offer a novel approach to overcome these problems and here we ask if creation of "stealth" islets encapsulated within a thin cage of pegylated material of 100-200 nanometers thick provides a viable option for islet transplantation. The aims of this study were to test islet viability and functionality following encapsulation within the pegylated cage, and functional efficacy in vivo in terms of graft-derived control of normoglycemia in diabetic mice. We first demonstrated that pegylation of the islet surface, plus or minus nanoparticles, improved long-term islet viability in vitro compared to non-pegylated (naked control islets. Moreover, pegylation of the islets with nanoparticles was compatible with glucose-stimulated insulin secretion and insulin biogenesis. We next looked for functionality of the created "stealth" DBA/2 (H-2(d islets in vivo by comparing glycemic profiles across 4 groups of streptozotozin-induced diabetic C57BL/6 (H-2(b recipients of (i naked islets; (ii pegylated islets; (iii pegylated islets with nanoparticles (empty; and (iv pegylated islets with nanoparticles loaded with a cargo of leukemia inhibitory factor (LIF, a factor both promotes adaptive immune tolerance and regulates pancreatic β cell mass. Without any other treatment, normoglycemia was lost after 17 d (+/-7.5 d in control group. In striking contrast, recipients in groups (ii, (iii, and (iv showed long-term (>100 d normoglycemia involving 30%; 43%, and 57% of the recipients in each respective group. In conclusion, construction of "stealth" islets by pegylation-based nanotherapeutics not only supports islet structure and function, but also effectively isolates the islets from immune

  10. Minireview: Directed Differentiation and Encapsulation of Islet β-Cells-Recent Advances and Future Considerations.

    Science.gov (United States)

    Tse, Hubert M; Kozlovskaya, Veronika; Kharlampieva, Eugenia; Hunter, Chad S

    2015-10-01

    Diabetes mellitus has rapidly become a 21st century epidemic with the promise to create vast economic and health burdens, if left unchecked. The 2 major forms of diabetes arise from unique causes, with outcomes being an absolute (type 1) or relative (type 2) loss of functional pancreatic islet β-cell mass. Currently, patients rely on exogenous insulin and/or other pharmacologies that restore glucose homeostasis. Although these therapies have prolonged countless lives over the decades, the striking increases in both type 1 and type 2 diabetic diagnoses worldwide suggest a need for improved treatments. To this end, islet biologists are developing cell-based therapies by which a patient's lost insulin-producing β-cell mass is replenished. Pancreatic or islet transplantation from cadaveric donors into diabetic patients has been successful, yet the functional islet demand far surpasses supply. Thus, the field has been striving toward transplantation of renewable in vitro-derived β-cells that can restore euglycemia. Challenges have been numerous, but progress over the past decade has generated much excitement. In this review we will summarize recent findings that have placed us closer than ever to β-cell replacement therapies. With the promise of cell-based diabetes therapies on the horizon, we will also provide an overview of cellular encapsulation technologies that will deliver critical protection of newly implanted cells.

  11. Assessment of Mitochondrial DNA as an Indicator of Islet Quality: An Example in Goto Kakizaki Rats

    Czech Academy of Sciences Publication Activity Database

    Alán, Lukáš; Špaček, Tomáš; Zelenka, Jaroslav; Tauber, Jan; Berková, Z.; Zacharovová, K.; Saudek, F.; Ježek, Petr

    2011-01-01

    Roč. 43, č. 9 (2011), s. 3281-3284 ISSN 0041-1345. [World Congress of the International Pancreas and Islet Transplant Association /13./. Praha, 01.06.2011-04.06.2011] R&D Projects: GA MZd NS10219 Institutional research plan: CEZ:AV0Z50110509 Keywords : type 2 diabetes * mtDNA * beta-cells Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.005, year: 2011

  12. Microfabricated biocapsules for the immunoisolation of pancreatic islets of Langerhans

    Science.gov (United States)

    Desai, Tejal Ashwin

    1998-08-01

    A silicon-based microfabricated biocapsule was developed and evaluated for use in the immunoisolation of transplanted cells, specifically pancreatic islets of Langerhans for the treatment of Type I diabetes. The transplantation of cells with specific functions is a promising therapy for a wide variety of pathologies including diabetes, Parkinson's, and hemophilia. Such transplanted cells, however, are sensitive to both cellular and humoral immune rejection as well as damage by autoimmune activity, without chronic immunosuppression. The research presented in this dissertation investigated whether microfabricated silicon-based biocapsules, with uniform membrane pore sizes in the tens of nanometer range, could provide an immunoprotective environment for pancreatic islets and other insulin-secreting cell lines, while maintaining cell viability and functionality. By utilizing fabrication techniques commonly employed in the microelectronics industry (MEMS), membranes were fabricated with precisely controlled and uniform pore sizes, allowing the optimization of biocapsule membrane parameters for the encapsulation of specific hormone-secreting cell types. The biocapsule-forming process employed bulk micromachining to define cell-containing chambers within single crystalline silicon wafers. These chambers interface with the surrounding biological environment through polycrystalline silicon filter membranes, which were surface micromachined to present a high density of uniform pores to allow sufficient permeability to oxygen, glucose, and insulin. Both in vitro and in vivo experiments established the biocompatibility of the microfabricated biocapsule, and demonstrated that encapsulated cells could live and function normally in terms of insulin-secretion within microfabricated environments for extended periods of time. This novel research shows the potential of using microfabricated biocapsules for the encapsulation of several different cell xenografts. The semipermeability

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

    Directory of Open Access Journals (Sweden)

    Jakob D Wikstrom

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

  14. Microencapsulation of Islets for the Treatment of Type 1 Diabetes Mellitus (T1D).

    Science.gov (United States)

    Calafiore, Riccardo; Basta, Giuseppe; Montanucci, Pia

    2017-01-01

    Microencapsulation technology, based on use of alginic acid biopolymers, has been devised many years ago. However, when intended for enveloping human islets for transplantation purposes, the method needs to be up-scaled and implemented with care being taken to comply with simple but important measures. It is almost indispensable to rely on an ultrapurified alginic polymers: in fact, any, even minimal, alginate contamination with endotoxins, pyrogens, and proteins could provoke the host's inflammatory reaction upon graft, with heavy adverse consequences on the capsules immunoprotective properties, hence on graft survival per se. Care should be taken in ensuring fabrication of reproducible microspheres, in terms not only of shape and size, but also consistency of the peripheral layers around the central alginate gel core, where the islets are immobilized. Once the product is well defined and stable, care should also be taken in accurately selecting patients with T1D that are candidate for encapsulated islet cell transplantation with no general immunosuppression. A series of pre- and post-intraperitoneal transplant metabolic, chemical, and immunological parameters are to be monitored, in conjunction with image analysis of the abdomen, in order to assess efficacy of the intervention according to well defined grading scale.

  15. 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.

  16. Pro-inflammatory and pro-oxidant status of pancreatic islet in vitro is controlled by TLR-4 and HO-1 pathways.

    Science.gov (United States)

    Vivot, Kevin; Langlois, Allan; Bietiger, William; Dal, Stéphanie; Seyfritz, Elodie; Pinget, Michel; Jeandidier, Nathalie; Maillard, Elisa; Gies, Jean-Pierre; Sigrist, Séverine

    2014-01-01

    Since their isolation until implantation, pancreatic islets suffer a major stress leading to the activation of inflammatory reactions. The maintenance of controlled inflammation is essential to preserve survival and function of the graft. Identification and targeting of pathway(s) implicated in post-transplant detrimental inflammatory events, is mandatory to improve islet transplantation success. We sought to characterize the expression of the pro-inflammatory and pro-oxidant mediators during islet culture with a focus on Heme oxygenase (HO-1) and Toll-like receptors-4 signaling pathways. Rat pancreatic islets were isolated and pro-inflammatory and pro-oxidant status were evaluated after 0, 12, 24 and 48 hours of culture through TLR-4, HO-1 and cyclooxygenase-2 (COX-2) expression, CCL-2 and IL-6 secretion, ROS (Reactive Oxygen Species) production (Dihydroethidine staining, DHE) and macrophages migration. To identify the therapeutic target, TLR4 inhibition (CLI-095) and HO-1 activation (cobalt protoporphyrin,CoPP) was performed. Activation of NFκB signaling pathway was also investigated. After isolation and during culture, pancreatic islet exhibited a proinflammatory and prooxidant status (increase levels of TLR-4, COX-2, CCL-2, IL-6, and ROS). Activation of HO-1 or inhibition of TLR-4 decreased inflammatory status and oxidative stress of islets. Moreover, the overexpression of HO-1 induced NFκB phosphorylation while the inhibition of TLR-4 had no effect NFκB activation. Finally, inhibition of pro-inflammatory pathway induced a reduction of macrophages migration. These data demonstrated that the TLR-4 signaling pathway is implicated in early inflammatory events leading to a pro-inflammatory and pro-oxidant status of islets in vitro. Moreover, these results provide the mechanism whereby the benefits of HO-1 target in TLR-4 signaling pathway. HO-1 could be then an interesting target to protect islets before transplantation.

  17. Cyclic AMP in rat pancreatic islets

    International Nuclear Information System (INIS)

    Grill, V.; Borglund, E.; Cerasi, E.; Uppsala Univ.

    1977-01-01

    The incorporation of [ 3 H]adenine into cyclic AMP was studied in rat pancreatic islets under varying conditions of labeling. Prolonging the exposure to [ 3 H]adenine progressively augmented the islet cyclic [ 3 H]AMP level. Islets labeled for different periods of time and subsequently incubated (without adenine) in the presence of D-glucose or cholera toxin showed stimulations of intra-islet cyclic [ 3 H]AMP that were proportionate to the levels of radioactive nucleotide present under non-stimulatory conditions. Labeling the islets in a high glucose concentration (27.7 mM) did not modify the nucleotide responses to glucose or cholera toxin. The specific activity of cyclic [ 3 H]AMP, determined by simultaneous assay of cyclic [ 3 H]AMP and total cyclic AMP, was not influenced by glucose or cholera toxin. Glucose had no effect on the specific activity of labeled ATP

  18. Immunological Challenges Facing Translation of Alginate Encapsulated Porcine Islet Xenotransplantation to Human Clinical Trials.

    Science.gov (United States)

    Krishnan, Rahul; Ko, David; Foster, Clarence E; Liu, Wendy; Smink, A M; de Haan, Bart; De Vos, Paul; Lakey, Jonathan R T

    2017-01-01

    Transplantation of alginate-encapsulated islets has the potential to treat patients suffering from type I diabetes, a condition characterized by an autoimmune attack against insulin-secreting beta cells. However, there are multiple immunological challenges associated with this procedure, all of which must be adequately addressed prior to translation from trials in small animal and nonhuman primate models to human clinical trials. Principal threats to graft viability include immune-mediated destruction triggered by immunogenic alginate impurities, unfavorable polymer composition and surface characteristics, and release of membrane-permeable antigens, as well as damage associated molecular patterns (DAMPs) by the encapsulated islets themselves. The lack of standardization of significant parameters of bioencapsulation device design and manufacture (i.e., purification protocols, surface-modification grafting techniques, alginate composition modifications) between labs is yet another obstacle that must be overcome before a clinically effective and applicable protocol for encapsulating islets can be implemented. Nonetheless, substantial progress is being made, as is evident from prolonged graft survival times and improved protection from immune-mediated graft destruction reported by various research groups, but also with regard to discoveries of specific pathways involved in explaining observed outcomes. Progress in the latter is essential for a comprehensive understanding of the mechanisms responsible for the varying levels of immunogenicity of certain alginate devices. Successful translation of encapsulated islet transplantation from in vitro and animal model testing to human clinical trials hinges on application of this knowledge of the pathways and interactions which comprise immune-mediated rejection. Thus, this review not only focuses on the different factors contributing to provocation of the immune reaction by encapsulated islets, but also on the defining

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

    Directory of Open Access Journals (Sweden)

    Feng-Cheng Chou

    2012-01-01

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

  20. Pancreatic islets of variable size - insulin secretion and glucose utilization

    International Nuclear Information System (INIS)

    Colella, R.M.; Bonner-Weir, S.; Braunstein, L.P.; Schwalke, M.; Weir, G.C.

    1985-01-01

    Glucose metabolism and insulin secretion were studied in isolated rat pacreatic islets of different sizes and the amount of tissue was quantitated by the measurement of DNA. It was found that larger islets (140-210 ng DNA/islet) utilized more glucose (based on the conversion of 3 H-5-glucose to 3 H 2 O) per ng of DNA than islets containing less DNA (60-120 ng/islet). However, the insulin secreted per ng of DNA in response to a given glucose concentration was the same in islets of all sizes. Also, the islet insulin and glucagon content when expressed in terms of DNA did not depend upon islet size. Thus, although glucose utilization rates expressed as a function of islet DNA content were greater in larger islets, no such relationship was found for glucose-induced insulin release or insulin and glucagon content. 17 reference, 1 figure, 3 tables

  1. Autoreactive effector/memory CD4+ and CD8+ T cells infiltrating grafted and endogenous islets in diabetic NOD mice exhibit similar T cell receptor usage.

    Directory of Open Access Journals (Sweden)

    Ramiro Diz

    Full Text Available Islet transplantation provides a "cure" for type 1 diabetes but is limited in part by recurrent autoimmunity mediated by β cell-specific CD4(+ and CD8(+ T cells. Insight into the T cell receptor (TCR repertoire of effector T cells driving recurrent autoimmunity would aid the development of immunotherapies to prevent islet graft rejection. Accordingly, we used a multi-parameter flow cytometry strategy to assess the TCR variable β (Vβ chain repertoires of T cell subsets involved in autoimmune-mediated rejection of islet grafts in diabetic NOD mouse recipients. Naïve CD4(+ and CD8(+ T cells exhibited a diverse TCR repertoire, which was similar in all tissues examined in NOD recipients including the pancreas and islet grafts. On the other hand, the effector/memory CD8(+ T cell repertoire in the islet graft was dominated by one to four TCR Vβ chains, and specific TCR Vβ chain usage varied from recipient to recipient. Similarly, islet graft- infiltrating effector/memory CD4(+ T cells expressed a limited number of prevalent TCR Vβ chains, although generally TCR repertoire diversity was increased compared to effector/memory CD8(+ T cells. Strikingly, the majority of NOD recipients showed an increase in TCR Vβ12-bearing effector/memory CD4(+ T cells in the islet graft, most of which were proliferating, indicating clonal expansion. Importantly, TCR Vβ usage by effector/memory CD4(+ and CD8(+ T cells infiltrating the islet graft exhibited greater similarity to the repertoire found in the pancreas as opposed to the draining renal lymph node, pancreatic lymph node, or spleen. Together these results demonstrate that effector/memory CD4(+ and CD8(+ T cells mediating autoimmune rejection of islet grafts are characterized by restricted TCR Vβ chain usage, and are similar to T cells that drive destruction of the endogenous islets.

  2. 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

  3. Fission of pancreatic islets during postnatal growth of the mouse.

    Science.gov (United States)

    Seymour, Philip A; Bennett, William R; Slack, Jonathan M W

    2004-02-01

    A cell composition analysis was made of the pancreatic islets in postnatal H253 mice. This line has a lacZ insertion on the X chromosome so that in female hemizygotes 50% of cells should be positive for beta-galactosidase and 50% negative. Immediately after birth, the islets were of a heterogeneous cell composition. However, by 4 weeks some islets have become homogeneous. This suggests that islets progress towards monoclonality in a similar way to the intestinal crypts and stomach gastric glands. Pancreatic islets may therefore represent 'structural proliferative units' in the overall histological organization of the pancreas. Reduction of genetic heterogeneity might arise from cell turnover, fission of islets or both. Analysis of the cell composition of the X-inactivation mosaic mice also provides the first clear evidence for islet fission in pancreatic development. Irregularly shaped islets resembling dumb-bells, with a characteristic neck of alpha-cells, were observed with decreasing frequency with increasing age. Three-dimensional reconstruction confirmed their resemblance to conjoined islets. The cell composition analysis showed: (1) the relatedness of the two sides of a dumb-bell islet is significantly higher than between two non-dumb-bell islets and (2) the relatedness of two randomly selected islets decreases as the distance between them increases. This suggests that dumb-bell islets are in a state of fission rather than fusion, and that islet fission is a mode of islet production in the postnatal pancreas.

  4. Islet neogenesis potential of human adult stem cells and its applications in cell replacement therapy for diabetes

    Directory of Open Access Journals (Sweden)

    Bhonde RR

    2008-11-01

    Full Text Available In recent years regenerative biology has reached to greater heights due to its therapeutic potential in treating degenerative diseases; as they are not curable by modern medicine. With the advent of research in stem cells and developmental biology the regenerative potential of adult resident stem cells is becoming clearer. The long term objective of regenerative medicine or cell therapy is to treat patients with their own stem cells. These stem cells could be derived from the diseased organs such as skin, liver, pancreas etc. or from reservoirs of multipotent stem cells such as bone marrow or cord blood.Manipulating the ability of tissue resident stem cells as well as from multipotent reservoirs such as bone marrow, umbilical cord and cord blood to give rise to endocrine cells may open new avenues in the treatment of diabetes. A better understanding of stem cell biology would almost certainly allow for the establishment of efficient and reliable cell transplantation experimental programs in the clinic. We show here that multipotent mesenchymal stem cells can be isolated from various sources such as the bone marrow, placenta, umbilical cord. Upon stimulation with specific growth factors they differentiate into islet like clusters (ILCs. When ILCs obtained from the above mentioned sources were transplanted in experimental diabetic mice, restoration of normoglycemia was observed within three weeks of transplantation with concomitant increase in the body weight. These euglycemic mice exhibited normal glucose tolerance test indicating normal utilization of glucose. Allthough the MSCs isolated from all the sources had the same characteristics; they showed significant differences in their islet differentiation potential. ILCs isolated for the human bone marrow did not show any pancreatic hormones in vitro, but upon transplantation they matured into insulin and somatostatin producing hormones. Placental MSCs as well as ILCs showed insulin trascripts

  5. Long-Term Glycemic Control in Adult Patients Undergoing Remote vs. Local Total Pancreatectomy With Islet Autotransplantation.

    Science.gov (United States)

    Kesseli, Samuel J; Wagar, Matthew; Jung, Min K; Smith, Kerrington D; Lin, Yu Kuei; Walsh, R Matthew; Hatipoglu, Betul; Freeman, Martin L; Pruett, Timothy L; Beilman, Gregory J; Sutherland, David E R; Dunn, Ty B; Axelrod, David A; Chaidarun, Sushela S; Stevens, Tyler K; Bellin, Melena; Gardner, Timothy B

    2017-04-01

    Total pancreatectomy with islet autotransplantation (TPIAT) is increasingly performed with remote islet cell processing and preparation, i.e., with islet cell isolation performed remotely from the primary surgical site at an appropriately equipped islet isolation facility. We aimed to determine whether TPIAT using remote islet isolation results in comparable long-term glycemic outcomes compared with TPIAT performed with standard local isolation. We performed a retrospective cohort study of adult patients who underwent TPIAT at three tertiary care centers from 2010 to 2013. Two centers performed remote isolation and one performed local isolation. Explanted pancreata in the remote cohort were transported ∼130 miles to and from islet isolation facilities. The primary outcome was insulin independence 1 year following transplant. Baseline characteristics were similar between groups except the remote cohort had higher preoperative hemoglobin A1c (HbA1c; 5.43 vs. 5.25, P=0.02) and there were more females in the local cohort (58% vs. 76%, P=0.049). At 1 year, 27% of remote and 32% of local patients were insulin independent (P=0.48). Remote patients experienced a greater drop in fasting c-peptide (-1.66 vs. -0.64, P=0.006) and a greater rise in HbA1c (1.65 vs. 0.99, P=0.014) at 1-year follow-up. A preoperative c-peptide >2.7 (odds ratio (OR) 4.4, 95% confidence interval (CI) 1.6-14.3) and >3,000 islet equivalents/kg (OR 11.0, 95% CI 3.2-37.3) were associated with one-year insulin independence in the local group. At 1 year after TPIAT, patients undergoing remote surgery have equivalent rates of long-term insulin independence compared with patients undergoing TPIAT locally, but metabolic control is superior with local isolation.

  6. Postnatally disturbed pancreatic islet cell distribution in human islet amyloid polypeptide transgenic mice

    NARCIS (Netherlands)

    Wong, HY; Ahren, B; Lips, CJM; Hoppener, JWM; Sundler, F

    2003-01-01

    Objective: Islet amyloid polypeptide (IAPP)/amylin is produced by the pancreatic islet beta-cells, which also produce insulin. To study potential functions of IAPP, we have generated transgenic mice overexpressing human IAPP (hIAPP) in the beta-cells. These mice show a diabetic phenotype when

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

    DEFF Research Database (Denmark)

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

    1987-01-01

    strains, indicating that age, sex, and genetic background do not influence the susceptibility of the beta-cell to IL-1. Preculture of islets for 1-7 days in normal atmosphere and preculture of islet clusters in 95% O2 to delete passenger cells did not affect IL-1-mediated cytotoxicity, suggesting that IL...

  8. Islet isolation and GMP, ISO 9001:2000: what do we need--a 3-year experience.

    Science.gov (United States)

    Hengster, P; Hermann, M; Pirkebner, D; Draxl, A; Margreiter, R

    2005-10-01

    Pancreatic islet cell isolation and transplantation has been performed for many years at several institutions. Although all institutions aim to produce high-quality islets, applied standards widely deviate from standards in the pharmaceutical industry. The legal situation within the European Union has changed requirements for setting up and running such a laboratory. The process is now clearly defined as a production of a pharmaceutical and therefore must be licensed by federal authorities. Analysis of workload for establishing an islet isolation program that fulfil GMP and ISO 9001 criteria including an estimation of costs and the impact of such a system on the isolation process. The definition of quality parameters and documentation is a central issue of all islet isolation laboratories. Therefore, GMP and ISO 9001:2000 do not add additional work per se. On the other hand, clear guidelines, a clear policy, working place descriptions, forms, checklists, and, particularly standard operating procedures, are instrumental for smooth functioning within the department. Collection of data such as errors, improvement measures, and preventive measures reduces subsequent costs. A clear definition of responsibilities minimizes organizational problems. Steering of inspection devices prevents bias errors and validating the processes clearly points out incorrect assumptions. Documentation helps to prove the correctness of the production at any time and is of use also for scientific evaluations. We strongly feel that GMP criteria are mandatory and together with an ISO 9001:2000 quality management system offers significant advantages for the process of islet isolation and a continuous improvement process.

  9. DAMP production by human islets under low oxygen and nutrients in the presence or absence of an immunoisolating-capsule and necrostatin-1

    NARCIS (Netherlands)

    Paredes-Juarez, Genaro A.; Sahasrabudhe, Neha M.; Tjoelker, Reina S.; de Haan, Bart J.; Engelse, Marten A.; de Koning, Eelco J. P.; Faas, Marijke M.; de Vos, Paul

    2015-01-01

    In between the period of transplantation and revascularization, pancreatic islets are exposed to low-oxygen and low-nutrient conditions. In the present study we mimicked those conditions in vitro to study the involvement of different cell death processes, release of danger-associated molecular

  10. Polymer porous scaffolds for transplantation of Langerhans islets

    Czech Academy of Sciences Publication Activity Database

    Kubies, Dana

    2016-01-01

    Roč. 7, 2 (Suppl) (2016), s. 101 ISSN 2157-7552. [ International Conference on Tissue Engineering & Regenerative Medicine /5./. 12.09.2016-14.09.2016, Berlin] R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 Keywords : polymer scaffolds * porosity * vascularization Subject RIV: EB - Genetics ; Molecular Biology

  11. Kidney Transplant

    Science.gov (United States)

    ... Menu Menu Search Home Prevention Kidney Disease Patients Organ Donation & Transplantation Professionals Events Advocacy Donate A to Z Health ... Tests for Transplant Care After Kidney Transplant Common Organ Donation and Transplantation Terms The National Kidney Foundation (NKF) is the ...

  12. Glucose cycling in islets from healthy and diabetic rats

    International Nuclear Information System (INIS)

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

    1990-01-01

    Pancreatic islets from healthy (control) and neonatally streptozocin-induced diabetic (STZ-D) rats, a model for non-insulin-dependent diabetes mellitus, were incubated with 3 H 2 O and 5.5 or 16.7 mM glucose. At 5.5 mM glucose, no detectable [ 3 H]glucose was formed. At 16.7 mM, 2.2 patom.islet-1.h-1 of 3 H was incorporated into glucose by the control islets and 5.4 patom.islet-1.h-1 by STZ-D islets. About 75% of the 3 H was bound to carbon-2 of the glucose. Glucose utilization was 35.3 pmol.islet-1.h-1 by the control and 19.0 pmol.islet-1.h-1 by the STZ-D islets. Therefore, 4.5% of the glucose-6-phosphate formed by the control islets and 15.7% by the STZ-D islets was dephosphorylated. This presumably occurred in the beta-cells of the islets catalyzed by glucose-6-phosphatase. An increased glucose cycling, i.e., glucose----glucose-6-phosphate----glucose, in islets of STZ-D rats may contribute to the decreased insulin secretion found in these animals

  13. Trimodal Gadolinium-Gold Microcapsules Containing Pancreatic Islet Cells Restore Normoglycemia in Diabetic Mice and Can Be Tracked by Using US, CT, and Positive-Contrast MR Imaging

    Science.gov (United States)

    Arifin, Dian R.; Long, Christopher M.; Gilad, Assaf A.; Alric, Christophe; Roux, Stéphane; Tillement, Olivier; Link, Thomas W.; Arepally, Aravind; Bulte, Jeff W. M.

    2011-01-01

    Purpose: To develop microcapsules that immunoprotect pancreatic islet cells for treatment of type I diabetes and enable multimodal cellular imaging of transplanted islet cells. Materials and Methods: All animal experiments were approved by the institutional animal care and use committee. Gold nanoparticles functionalized with DTDTPA (dithiolated diethylenetriaminepentaacetic acid):gadolinium chelates (GG) were coencapsulated with pancreatic islet cells by using protamine sulfate as a clinical-grade alginate cross linker. Conventional poly-l-lysine–cross-linked microcapsules and unencapsulated islets were included as controls. The viability and glucose responsiveness of islet cells were assessed in vitro, and in vivo insulin (C-peptide) secretion was monitored for 6 weeks in (streptozotocin-induced) diabetic mice with (n = 7) or without (n = 8) intraabdominally engrafted islet cells. Five nondiabetic mice were included as controls. Differences between samples were calculated by using a nonparametric Wilcoxon Mann-Whitney method. To adjust for multiple comparisons, a significance level of P microcapsules could be readily visualized with positive-contrast high-field-strength MR imaging, micro-CT, and US both in vitro and in vivo. Conclusion: Cell encapsulation with GG provides a means of trimodal noninvasive tracking of engrafted cells. © RSNA, 2011 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101608/-/DC1 PMID:21734156

  14. Islet amyloid formation is an important determinant for inducing islet inflammation in high-fat-fed human IAPP transgenic mice.

    Science.gov (United States)

    Meier, Daniel T; Morcos, Mary; Samarasekera, Thanya; Zraika, Sakeneh; Hull, Rebecca L; Kahn, Steven E

    2014-09-01

    Amyloid deposition and inflammation are characteristic of islet pathology in type 2 diabetes. The aim of this study was to determine whether islet amyloid formation is required for the development of islet inflammation in vivo. Human islet amyloid polypeptide transgenic mice and non-transgenic littermates (the latter incapable of forming islet amyloid) were fed a low-fat (10%) or high-fat (60%) diet for 12 months; high-fat feeding induces islet amyloid formation in transgenic mice. At the conclusion of the study, glycaemia, beta cell function, islet amyloid deposition, markers of islet inflammation and islet macrophage infiltration were measured. Fasting plasma glucose levels did not differ by diet or genotype. Insulin release in response to i.v. glucose was significantly greater in both high vs low fat groups, and significantly lower in both transgenic compared with non-transgenic groups. Only high-fat-fed transgenic mice developed islet amyloid and showed a trend towards reduced beta cell area. Compared with islets from low-fat-fed transgenic or high-fat-fed non-transgenic mice, islets of high-fat-fed transgenic mice displayed a significant increase in the expression of genes encoding chemokines (Ccl2, Cxcl1), macrophage/dendritic cell markers (Emr1, Itgax), NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome components (Nlrp3, Pycard, Casp1) and proinflammatory cytokines (Il1b, Tnf, Il6), as well as increased F4/80 staining, consistent with increased islet inflammation and macrophage infiltration. Our results indicate that islet amyloid formation is required for the induction of islet inflammation in this long-term high-fat-diet model, and thus could promote beta cell dysfunction in type 2 diabetes via islet inflammation.

  15. β-cell transplantation in diabetes mellitus

    Directory of Open Access Journals (Sweden)

    S Pellegrini

    2013-11-01

    Full Text Available Patients with diabetes mellitus suffer either from destruction of pancreatic β-cells or progressive deterioration of their function. Thus, transplantation of an intact β-cell population fully capable of insulin secretion is the only means to cure this disease. Despite glycemic benefits and decrease in risks for late complications, islet transplantation or complete pancreatic grafting in humans remains a challenge due to necessity of lifetime immunosuppression and increasingly sparse donor resources. Current paper presents a review of modern endeavours to obtain a limitless source for glucose-sensitive insulin secreting cells. We discuss, in particular, complex aspects of β-cell proliferation and/or neogenesis in vivo, issues with xenogenous pancreatic islets, and latest advances in controlled differentiation of embryonic and induced polypotent stem cells – the most promising and relevant source of β-cells.

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

    DEFF Research Database (Denmark)

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

    1987-01-01

    We recently demonstrated that the macrophage product interleukin 1 (IL-1) is cytotoxic to isolated pancreatic islets and hypothesized that IL-1 is responsible for beta-cell destruction in insulin-dependent diabetes mellitus (IDDM). We studied whether the variation in IDDM preponderance with age...... strains, indicating that age, sex, and genetic background do not influence the susceptibility of the beta-cell to IL-1. Preculture of islets for 1-7 days in normal atmosphere and preculture of islet clusters in 95% O2 to delete passenger cells did not affect IL-1-mediated cytotoxicity, suggesting that IL...

  17. Evaluation of low doses BPA-induced perturbation of glycemia by toxicogenomics points to a primary role of pancreatic islets and to the mechanism of toxicity.

    Science.gov (United States)

    Carchia, E; Porreca, I; Almeida, P J; D'Angelo, F; Cuomo, D; Ceccarelli, M; De Felice, M; Mallardo, M; Ambrosino, C

    2015-10-29

    Epidemiologic and experimental studies have associated changes of blood glucose homeostasis to Bisphenol A (BPA) exposure. We took a toxicogenomic approach to investigate the mechanisms of low-dose (1 × 10(-9 )M) BPA toxicity in ex vivo cultures of primary murine pancreatic islets and hepatocytes. Twenty-nine inhibited genes were identified in islets and none in exposed hepatocytes. Although their expression was slightly altered, their impaired cellular level, as a whole, resulted in specific phenotypic changes. Damage of mitochondrial function and metabolism, as predicted by bioinformatics analyses, was observed: BPA exposure led to a time-dependent decrease in mitochondrial membrane potential, to an increase of ROS cellular levels and, finally, to an induction of apoptosis, attributable to the bigger Bax/Bcl-2 ratio owing to activation of NF-κB pathway. Our data suggest a multifactorial mechanism for BPA toxicity in pancreatic islets with emphasis to mitochondria dysfunction and NF-κB activation. Finally, we assessed in vitro the viability of BPA-treated islets in stressing condition, as exposure to high glucose, evidencing a reduced ability of the exposed islets to respond to further damages. The result was confirmed in vivo evaluating the reduction of glycemia in hyperglycemic mice transplanted with control and BPA-treated pancreatic islets. The reported findings identify the pancreatic islet as the main target of BPA toxicity in impairing the glycemia. They suggest that the BPA exposure can weaken the response of the pancreatic islets to damages. The last observation could represent a broader concept whose consideration should lead to the development of experimental plans better reproducing the multiple exposure conditions.

  18. Pancreas transplantation in the treatment of diabetes mellitus type 1: modern aspects

    OpenAIRE

    S. V. Gautier; S. V. Arzumanov

    2017-01-01

    Diabetes mellitus is a significant social problem. In the Russian Federation, the prevalence of diabetes type 1 is 340.000 people, 21% of them having diabetic nephropathy, as well as other secondary complications leading to disability and high mortality. There are several options for diabetic patients with chronic kidney disease dialysis: kidney transplantation with insulin therapy, simultaneous kidney-pancreas transplant or islet transplant. Good long-term results could be obtained by the wh...

  19. Endovascular Method for Transplantation of Insulin-Producing Cells to the Pancreas Parenchyma in Swine

    OpenAIRE

    Lundberg, J; Stone-Elander, S; Zhang, X-M; Korsgren, O; Jonsson, S; Holmin, S

    2014-01-01

    Insulin-producing cells are transplanted by portal vein injection as an alternative to pancreas transplantation in both clinical and preclinical trials. Two of the main limitations of portal vein transplantation are the prompt activation of the innate immunity and concomitant loss of islets and a small but significant risk of portal vein thrombosis. Furthermore, to mimic physiological release, the insulin-producing cells should instead be located in the pancreas. The trans-vessel wall approac...

  20. Islet neuropeptide Y receptors are functionally conserved and novel targets for the preservation of beta-cell mass.

    Science.gov (United States)

    Franklin, Zara J; Tsakmaki, Anastasia; Fonseca Pedro, Patricia; King, Aileen J; Huang, Guo Cai; Amjad, Sakeena; Persaud, Shanta J; Bewick, Gavin A

    2018-03-01

    Two unmet therapeutic strategies for diabetes treatment are prevention of beta-cell death and stimulation of beta-cell replication. Our aim was to characterize the role of neuropeptide Y receptors in the control of beta-cell mass. We used endogenous and selective agonists of the NPY receptor system to explore its role in the prevention of beta-cell apoptosis and proliferation in islets isolated from both mouse and human donors. We further explored the intra-cellular signalling cascades involved, using chemical inhibitors of key signalling pathways. As proof of principle we designed a long-acting analogue of [Leu 31 Pro 34 ]-NPY, an agonist of the islet-expressed Y receptors, to determine if targeting this system could preserve beta-cell mass in vivo. Our data reveal that NPY Y1, 4 and 5 receptor activation engages a generalized and powerful anti-apoptotic pathway that protects mouse and human islets from damage. These anti-apoptotic effects were dependent on stimulating a Gαi-PLC-PKC signalling cascade, which prevented cytokine-induced NFkB signalling. NPY receptor activation functionally protected islets by restoring glucose responsiveness following chemically induced injury in both species. NPY receptor activation attenuated beta-cell apoptosis, preserved functional beta-cell mass and attenuated the hyperglycaemic phenotype in a low-dose streptozotocin model of diabetes. Taken together, our observations identify the islet Y receptors as promising targets for the preservation of beta-cell mass. As such, targeting these receptors could help to maintain beta-cell mass in both type 1 and type 2 diabetes, and may also be useful for improving islet transplantation outcomes. © 2017 John Wiley & Sons Ltd.

  1. Islet inflammation in type 2 diabetes and physiology

    Science.gov (United States)

    Nagai, Ryozo

    2017-01-01

    The finding of islet inflammation in type 2 diabetes (T2D) and its involvement in β cell dysfunction has further highlighted the significance of inflammation in metabolic diseases. The number of intra-islet macrophages is increased in T2D, and these cells are the main source of proinflammatory cytokines within islets. Multiple human studies of T2D have shown that targeting islet inflammation has the potential to be an effective therapeutic strategy. In this Review we provide an overview of the cellular and molecular mechanisms by which islet inflammation develops and causes β cell dysfunction. We also emphasize the regulation and roles of macrophage polarity shift within islets in the context of T2D pathology and β cell health, which may have broad translational implications for therapeutics aimed at improving islet function. PMID:28045399

  2. Irradiation for xenogeneic transplantation

    International Nuclear Information System (INIS)

    Halperin, E.C.; Knechtle, S.J.; Harland, R.C.; Yamaguchi, Yasua; Sontag, M.; Bollinger, R.R.; Duke Univ., Durham, NC

    1990-01-01

    Xenogeneic transplantation (XT) is the transplantation of organs or tissues from a member of one species to a member of another. Mammalian species frequently have circulating antibody which is directed against the foreign organ irrespective of known prior antigen exposure. This antibody may lead to hyperacute rejection once it ensues so efforts must be directed towards eliminating the pre-existing antibody. In those species in which hyperacute rejection of xenografts does not occur, cell-mediated refection, similar to allograft rejection, may occur. It is in the prevention of this latter form of refection that radiation is most likely to be beneficial in XT. Both total lymphoid irradiation (TLI) and selective lyphoid irradiation (LSI) have been investigated for use in conjunction with XT. TLI has contributed to the prolongation of pancreatic islet-cell xenografts from hamsters to rats. TLI has also markedly prolonged the survival of cardiac transplants from hamsters to rats. A more modest prolongation of graft survival has been seen with the use of TLI in rabbit-to-rat exchanges. Therapy with TLI, cyclosporine, and splenectomy has markedly prolonged the survival of liver transplants from hamsters to rats, and preliminary data suggest that TLI may contribute to the prolongation of graft survival in the transplantation of hearts from monkeys to baboons. SLI appears to have prolonged graft survival, when used in conjunction with anti-lymphocyte globulin, in hamster-to-rat cardiac graft exchanges. The current state of knowledge of the use of irradiaiton in experimental XT is reviewed. (author). 38 refs.; 1 fig.; 5 tabs

  3. β-Hairpin of Islet Amyloid Polypeptide Bound to an Aggregation Inhibitor

    Science.gov (United States)

    Mirecka, Ewa A.; Feuerstein, Sophie; Gremer, Lothar; Schröder, Gunnar F.; Stoldt, Matthias; Willbold, Dieter; Hoyer, Wolfgang

    2016-01-01

    In type 2 diabetes, the formation of islet amyloid consisting of islet amyloid polypeptide (IAPP) is associated with reduction in β-cell mass and contributes to the failure of islet cell transplantation. Rational design of inhibitors of IAPP amyloid formation has therapeutic potential, but is hampered by the lack of structural information on inhibitor complexes of the conformationally flexible, aggregation-prone IAPP. Here we characterize a β-hairpin conformation of IAPP in complex with the engineered binding protein β-wrapin HI18. The β-strands correspond to two amyloidogenic motifs, 12-LANFLVH-18 and 22-NFGAILS-28, which are connected by a turn established around Ser-20. Besides backbone hydrogen bonding, the IAPP:HI18 interaction surface is dominated by non-polar contacts involving hydrophobic side chains of the IAPP β-strands. Apart from monomers, HI18 binds oligomers and fibrils and inhibits IAPP aggregation and toxicity at low substoichiometric concentrations. The IAPP β-hairpin can serve as a molecular recognition motif enabling control of IAPP aggregation. PMID:27641459

  4. Human pancreatic islet progenitor cells demonstrate phenotypic ...

    Indian Academy of Sciences (India)

    2009-04-24

    Apr 24, 2009 ... 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 ...

  5. Human pancreatic islet progenitor cells demonstrate phenotypic ...

    Indian Academy of Sciences (India)

    Prakash

    exploring alternative sources of insulin-producing cells for cell based therapy in diabetes. Since in vitro culture of islet β-cells demonstrates loss in insulin (Beattie et al. 1999), several attempts have been made to identify stem / progenitor cells capable of differentiation into insulin-producing cells. Embryonic stem cells, which ...

  6. Kidney Transplant

    Science.gov (United States)

    ... type matches or is compatible to your own. Blood-type incompatible transplants are also possible but require additional medical treatment before and after transplant to reduce the risk of organ rejection. These are known as ABO incompatible kidney transplants. ...

  7. Kidney transplant

    Science.gov (United States)

    ... place a healthy kidney into a person with kidney failure . ... Renal transplant; Transplant - kidney ... Becker Y, Witkowski P. Kidney and pancreas transplantation. In: Townsend CM ... Urology . 11th ed. Philadelphia, PA: Elsevier; 2016: ...

  8. Lixisenatide accelerates restoration of normoglycemia and improves human beta-cell function and survival in diabetic immunodeficient NOD–scid IL-2rgnull RIP-DTR mice engrafted with human islets

    Directory of Open Access Journals (Sweden)

    Yang C

    2015-08-01

    Full Text Available Chaoxing Yang,1 Matthias Loehn,2 Agata Jurczyk,1 Natalia Przewozniak,1 Linda Leehy,1 Pedro L Herrera,3 Leonard D Shultz,4 Dale L Greiner,1 David M Harlan,5 Rita Bortell1 1Program in Molecular Medicine, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA; 2Sanofi-Aventis, Diabetes Division, Frankfurt, Germany; 3University of Geneva, Geneva, Switzerland; 4The Jackson Laboratory, Bar Harbor, ME, USA; 5Department of Medicine, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA Objective: Glucagon-like peptide-1 induces glucose-dependent insulin secretion and, in rodents, increases proliferation and survival of pancreatic beta cells. To investigate the effects on human beta cells, we used immunodeficient mice transplanted with human islets. The goal was to determine whether lixisenatide, a glucagon-like peptide-1 receptor agonist, improves human islet function and survival in vivo. Methods: Five independent transplant studies were conducted with human islets from five individual donors. Diabetic human islet-engrafted immunodeficient mice were treated with lixisenatide (50, 150, and 500 µg/kg or vehicle. Islet function was determined by blood glucose, plasma human insulin/C-peptide, and glucose tolerance tests. Grafts were analyzed for total beta- and alpha-cell number, percent proliferation, and levels of apoptosis. Results: Diabetic mice transplanted with marginal human islet mass and treated with lixisenatide were restored to euglycemia more rapidly than vehicle-treated mice. Glucose tolerance tests, human plasma insulin, and glucose-stimulation indices of lixisenatide-treated mice were significantly improved compared to vehicle-treated mice. The percentages of proliferating or apoptotic beta cells at graft recovery were not different between lixisenatide-treated and vehicle-treated mice. Nevertheless, in one experiment we found a significant twofold to threefold

  9. Islet β-Cell Mass Preservation and Regeneration in Diabetes Mellitus: Four Factors with Potential Therapeutic Interest

    Directory of Open Access Journals (Sweden)

    Jose Manuel Mellado-Gil

    2012-01-01

    Full Text Available Islet β-cell replacement and regeneration are two promising approaches for the treatment of Type 1 Diabetes Mellitus. Indeed, the success of islet transplantation in normalizing blood glucose in diabetic patients has provided the proof of principle that cell replacement can be employed as a safe and efficacious treatment. Nonetheless, shortage of organ donors has hampered expansion of this approach. Alternative sources of insulin-producing cells are mandatory to fill this gap. Although great advances have been achieved in generating surrogate β-cells from stem cells, current protocols have yet to produce functionally mature insulin-secreting cells. Recently, the concept of islet regeneration in which new β-cells are formed from either residual β-cell proliferation or transdifferentiation of other endocrine islet cells has gained much interest as an attractive therapeutic alternative to restore β-cell mass. Complementary approaches to cell replacement and regeneration could aim at enhancing β-cell survival and function. Herein, we discuss the value of Hepatocyte Growth Factor (HGF, Glucose-Dependent Insulinotropic Peptide (GIP, Paired box gene 4 (Pax4 and Liver Receptor Homolog-1 (LRH-1 as key players for β-cell replacement and regeneration therapies. These factors convey β-cell protection and enhanced function as well as facilitating proliferation and transdifferentiation of other pancreatic cell types to β-cells, under stressful conditions.

  10. Islet formation during the neonatal development in mice.

    Directory of Open Access Journals (Sweden)

    Kevin Miller

    2009-11-01

    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. A rapid radioimmunoassay for insulin suitable for testing pancreatic tissue prior to transplantation

    International Nuclear Information System (INIS)

    Besch, W.; Kohnert, K.-D.; Hahn, H.-J.; Ziegler, M.; Lorenz, D.

    1984-01-01

    One way of diabetes mellitus treatment is the transplantation of insulin-producing tissue. As islet or pancreas transplantation has made progress, testing of the tissue for its vitality, insulin content and insulin secretory response prior to transplantation became necessary. Apart from problems of rejection of allografted tissue, improvement of the patients metabolic control partly depends on the insulin content of the tissue transplanted. It was the aim of the present work to establish a radioimmunoassay which ensures rapid determination of immunoreactive insulin concentrations (IRI) either intracellularly-stored or released upon stimulation of human pancreas or islet with glucose, and to demonstrate the useful application of this assay for the assessment of transplantable tissue. (Auth.)

  12. Effects of micro-encapsulation on morphology and endocrine function of cryopreserved neonatal porcine islet-like cell clusters.

    Science.gov (United States)

    Murakami, M; Satou, H; Kimura, T; Kobayashi, T; Yamaguchi, A; Nakagawara, G; Iwata, H

    2000-10-27

    For the success of clinical islets transplantation, the development of a long-term storage method is necessary. However, the structure of digested islets is scanty for culture and cryopreservation. In this study, the effect of micro-encapsulation to cryopreserved porcine islet-like cell clusters (ICCs) was investigated. The ICCs prepared from neonatal pigs by collagenase digestion and culture technique were cryopreserved and micro-encapsulated in 5% agarose membranes. After cryopreservation, ICC cultured without encapsulation (group A) and cultured with encapsulation (group B) were assessed by comparison with no cryopreserved ICC (control) both in vitro by static incubation test and in vivo in a xenotransplantation study. Micro-encapsulation was able to maintain the fine morphology and the number of ICCs of group B after 7 days of culture. There were not significant differences in insulin secretion of group B and control on day 1 and 7 of culture (1 day:11+/-0.99, 7 days: 5.30+/-1.08 microU/ICC/hr NS versus control). On day 7 of culture, the retrieval rate of group B (105.2+/-9.8%) is obviously higher compared with group A (63.0+/-6.3%). In the xenotransplatation model, the ICCs of group B showed long survival time (7.9+/-0.4 weeks) and good transplantation effect. Our study suggests that micro-encapsulation is one of the useful method for cryopreserved ICC to maintain the fine morphology and effectively recover the endocrine function.

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

    Directory of Open Access Journals (Sweden)

    Gagliardino Juan J

    2001-10-01

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

  14. Experience of islet isolation without neutral protease supplementation

    OpenAIRE

    Kin, Tatsuya; O'Gorman, Doug; Senior, Peter; Shapiro, AM James

    2010-01-01

    We have reported improved islet isolation outcomes using a new digestion protocol where the pancreas is perfused only with collagenase, and neutral protease (NP) is administered during the digestion phase. Since the inception of this protocol, we have had some cases where administration of NP was not required. Our new protocol was utilized in 94 islet isolations. The timing of adding NP was dependent on the progression of digestion but in 10 cases the progression was rapid and most islets in ...

  15. DAMP production by human islets under low oxygen and nutrients in the presence or absence of an immunoisolating-capsule and necrostatin-1.

    Science.gov (United States)

    Paredes-Juarez, Genaro A; Sahasrabudhe, Neha M; Tjoelker, Reina S; de Haan, Bart J; Engelse, Marten A; de Koning, Eelco J P; Faas, Marijke M; de Vos, Paul

    2015-09-30

    In between the period of transplantation and revascularization, pancreatic islets are exposed to low-oxygen and low-nutrient conditions. In the present study we mimicked those conditions in vitro to study the involvement of different cell death processes, release of danger-associated molecular patterns (DAMP), and associated in vitro immune activation. Under low-oxygen and low-nutrient conditions, apoptosis, autophagy and necroptosis occur in human islets. Necroptosis is responsible for DAMP-release such as dsDNA, uric acid, and HMGB1. The sensors of the innate immune system able to recognize these DAMPs are mainly TLR, NOD receptors, and C-type lectins. By using cell-lines with a non-functional adaptor molecule MyD88, we were able to show that the islet-derived DAMPs signal mainly via TLR. Immunoisolation in immunoprotective membranes reduced DAMP release and immune activation via retention of the relative large DAMPs in the capsules. Another effective strategy was suppressing necroptosis using the inhibitor nec-1. Although the effect on cell-survival was minor, nec-1 was able to reduce the release of HMGB1 and its associated immune activation. Our data demonstrate that in the immediate post-transplant period islets release DAMPs that in vitro enhance responses of innate immune cells. DAMP release can be reduced in vitro by immunoisolation or intervention with nec-1.

  16. 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.

  17. Regulation of Pancreatic Islet Gene Expression in Mouse Islets by Pregnancy

    DEFF Research Database (Denmark)

    Layden, Brian Thomas; Durai, Vivek; Newman, Marsha V

    2010-01-01

    Pancreatic beta cells adapt to pregnancy-induced insulin resistance by unclear mechanisms. This study sought to identify genes involved in beta cell adaptation during pregnancy. To examine changes in global RNA expression during pregnancy, murine islets were isolated at a time point of increased......-inflammatory molecule. Complementing these studies, an expression array was performed to define pregnancy-induced changes in expression of G protein-coupled receptors which are known to impact islet cell function and proliferation. This assay, the results of which were confirmed using real time RT-PCR assays......, demonstrated that free fatty acid receptor 2 and cholecystokinin receptor A mRNA levels were increased at E13.5. This study has identified multiple novel targets that may be important for the adaptation of islets to pregnancy....

  18. Inhibition of carbachol-induced formation of inositolphosphates in isolated pancreatic islets

    DEFF Research Database (Denmark)

    Kardasz, A.M.J.; Capito, Kirsten; Hansen, Svend Erik

    1991-01-01

    Medicinsk biokemi, feed-back inhibition, phospholipase C, pancreatic islets, Calcium, proteinkinase C......Medicinsk biokemi, feed-back inhibition, phospholipase C, pancreatic islets, Calcium, proteinkinase C...

  19. Islet amyloid polypeptide and insulin expression are controlled differently in primary and transformed islet cells

    DEFF Research Database (Denmark)

    Madsen, O D; Michelsen, Bo Thomas; Westermark, P

    1991-01-01

    and immunocytochemistry. IAPP is primarily coexpressed with insulin in the beta-cell of GH-promoted primary rat islet cell cultures. Additionally, a small population of non-beta-cells exhibited a prominent IAPP expression, and double staining experiments showed colocalization with glucagon or somatostatin in some...... specificity of expressions of IAPP and insulin are controlled differently, and that coexpression of IAPP with hormones different from insulin may be a marker for pluripotent transformed rat islet cell clones, which are able to activate insulin gene transcription during passage in vivo....

  20. Biodistribution of adult derived human liver stem cells following intraportal infusion in a 17-year-old patient with glycogenosis type 1A

    International Nuclear Information System (INIS)

    Defresne, Florence; Tondreau, Tatiana; Stéphenne, Xavier; Smets, Françoise; Bourgois, Annick; Najimi, Mustapha; Jamar, François; Sokal, Etienne M.

    2014-01-01

    Introduction: Current treatment of inherited liver inborn errors of metabolism in children consists in appropriate diet and drugs and, for unstable patients, final orthotopic liver transplantation. Unfortunately, liver transplantation remains not easily available because of organ shortage and imposes inherent risks and lifelong immunosuppressive therapy. Therefore alternative treatments are required. Hepatocytes transplantation and its limitations led to consider innovative alternative such as transplantation of adult derived human liver stem cells (ADLHSC). These cells present high proliferative capacity, good resistance to cryopreservation and ability to differentiate into hepatocyte-like cells displaying mature hepatocyte functions. Aim: Biodistribution of ADHLSC had never been assessed after infusion through the portal vein in patients. This information is required to determine the safety of the method. Methods: ADHLSC were efficiently labelled with 111-Indium DTPA radiotracer and SPECT imaging was used for the acquisition of whole body imaging to document short term biodistribution of ADHLSC. Results: Following infusion through the portal vein, ADHLSC diffused homogenously throughout the liver and remained strictly within the targeted organ. Images were acquired until 5 days after infusion. At that time, no signal was observed in any other organs except the liver. Urinary excretion of 111-Indium DTPA was also monitored. Conclusion: For the first time, we documented the short term biodistribution of ADHLSC within the liver after infusion through the portal vein

  1. Approaches for imaging islets: recent advances and future prospects.

    NARCIS (Netherlands)

    Ahlgren, U.; Gotthardt, M.

    2010-01-01

    The establishment of improved technologies for imaging of the pancreas is a key element in addressing several aspects of diabetes pathogenesis. In this respect, the development of a protocol that allows for non-invasive scoring of human islets, or islet beta-cells, is of particular importance. The

  2. Hair transplant

    Science.gov (United States)

    ... this procedure: Scarring Unnatural-looking tufts of new hair growth It is possible that the transplanted hair will ... Most hair transplants result in excellent hair growth within several ... may be needed to create best results. The replaced hairs are ...

  3. Transplant rejection

    Science.gov (United States)

    ... Shortness of breath and less ability to exercise (heart transplant) Yellow skin color and easy bleeding (liver transplant) ... accountability. A.D.A.M. is among the first to achieve this important distinction for online health ...

  4. Intestine Transplant

    Science.gov (United States)

    ... to know FAQ Living donation What is living donation? Organs Types Being a living donor First steps Being ... Nursing Care of the Renal Transplant Recipient." UNOS Donation and Transplantation Nursing Curriculum . 1996 This Web site is intended ...

  5. Adipose derived mesenchymal stem cells transplantation via portal vein improves microcirculation and ameliorates liver fibrosis induced by CCl4 in rats

    Directory of Open Access Journals (Sweden)

    Wang Yu

    2012-06-01

    Full Text Available Abstract Introduction Adipose derived mesenchymal stem cells (ADMSCs, carrying the similar characteristics to bone marrow mesenchymal stem cells, only much more abundant and easier to obtain, may be a promising treatment for liver fibrosis. We aim to investigate the therapeutic potential of ADMSCs transplantation in liver fibrosis caused by carbon tetrachloride (CCl4 in rats as well as its underlying mechanism, and to further explore the appropriate infusion pathway. Methods ADMSCs were isolated, cultured and identified. Placebo and ADMSCs were transplanted via portal vein and tail vein respectively into carbon tetrachloride (CCl4-induced liver fibrosis rats. Computed tomography (CT perfusion scan and microvessel counts were performed to measure the alteration of liver microcirculation after therapy. Liver function tests and histological findings were estimated. Results CT perfusion scan shown significant decrease of hepatic arterial perfusion index, significant increased portal vein perfusion, total liver perfusion in rats receiving ADMSCs from portal vein, and Factor VIII (FVIII immunohistochemical staining shown significant decrease of microvessels in rats receiving ADMSCs from portal vein, indicating microcirculation improvement in portal vein group. Vascular endothelial growth Factor (VEGF was significantly up-regulated in fibrosis models, and decreased after ADMSCs intraportal transplantation. A significant improvement of liver functional test and histological findings in portal vein group were observed. No significance was found in rats receiving ADMSCs from tail vein. Conclusions ADMSCs have a therapeutic effect against CCl4-mediated liver fibrosis. ADMSCs may benefit the fibrotic liver through alteration of microcirculation, evidenced by CT perfusion scan and down-regulation of VEGF. Intraportal transplantation is a better pathway than tail vein transplantation.

  6. Microcapsules with Intrinsic Barium Radiopacity for Immunoprotection and X-ray/CT imaging of Pancreatic Islet Cells

    Science.gov (United States)

    Arifin, D.R.; Manek, S.; Call, E.; Arepally, A.; Bulte, J.W.M.

    2012-01-01

    Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444±21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-L-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mM barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3–4 weeks in vitro, with secreted human C-peptide levels of 0.2–160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. PMID:22444642

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

    Science.gov (United States)

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

    2017-05-15

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

  8. Microcapsules with intrinsic barium radiopacity for immunoprotection and X-ray/CT imaging of pancreatic islet cells.

    Science.gov (United States)

    Arifin, Dian R; Manek, Sameer; Call, Emma; Arepally, Aravind; Bulte, Jeff W M

    2012-06-01

    Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444 ± 21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-l-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mm barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3-4 weeks in vitro, with secreted human C-peptide levels of 0.2-160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. No Evidence of Viral Transmission following Long-Term Implantation of Agarose Encapsulated Porcine Islets in Diabetic Dogs

    Directory of Open Access Journals (Sweden)

    Lawrence S. Gazda

    2014-01-01

    Full Text Available We have previously described the use of a double coated agarose-agarose porcine islet macrobead for the treatment of type I diabetes mellitus. In the current study, the long-term viral safety of macrobead implantation into pancreatectomized diabetic dogs treated with pravastatin (n=3 was assessed while 2 dogs served as nonimplanted controls. A more gradual return to preimplant insulin requirements occurred after a 2nd implant procedure (days 148, 189, and >652 when compared to a first macrobead implantation (days 9, 21, and 21 in all macrobead implanted animals. In all three implanted dogs, porcine C-peptide was detected in the blood for at least 10 days following the first implant and for at least 26 days following the second implant. C-peptide was also present in the peritoneal fluid of all three implanted dogs at 6 months after 2nd implant and in 2 of 3 dogs at necropsy. Prescreening results of islet macrobeads and culture media prior to transplantation were negative for 13 viruses. No evidence of PERV or other viral transmission was found throughout the study. This study demonstrates that the long-term (2.4 years implantation of agarose-agarose encapsulated porcine islets is a safe procedure in a large animal model of type I diabetes mellitus.

  10. Core-shell hydrogel microcapsules for improved islets encapsulation.

    Science.gov (United States)

    Ma, Minglin; Chiu, Alan; Sahay, Gaurav; Doloff, Joshua C; Dholakia, Nimit; Thakrar, Raj; Cohen, Joshua; Vegas, Arturo; Chen, Delai; Bratlie, Kaitlin M; Dang, Tram; York, Roger L; Hollister-Lock, Jennifer; Weir, Gordon C; Anderson, Daniel G

    2013-05-01

    Islets microencapsulation holds great promise to treat type 1 diabetes. Currently used alginate microcapsules often have islets protruding outside capsules, leading to inadequate immuno-protection. A novel design of microcapsules with core-shell structures using a two-fluid co-axial electro-jetting is reported. Improved encapsulation and diabetes correction is achieved in a single step by simply confining the islets in the core region of the capsules. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Protein disulfide isomerase ameliorates β-cell dysfunction in pancreatic islets overexpressing human islet amyloid polypeptide.

    Science.gov (United States)

    Montane, Joel; de Pablo, Sara; Obach, Mercè; Cadavez, Lisa; Castaño, Carlos; Alcarraz-Vizán, Gema; Visa, Montserrat; Rodríguez-Comas, Júlia; Parrizas, Marcelina; Servitja, Joan Marc; Novials, Anna

    2016-01-15

    Human islet amyloid polypeptide (hIAPP) is the major component of amyloid deposits in islets of type 2 diabetic patients. hIAPP misfolding and aggregation is one of the factors that may lead to β-cell dysfunction and death. Endogenous chaperones are described to be important for the folding and functioning of proteins. Here, we examine the effect of the endoplasmic reticulum chaperone protein disulfide isomerase (PDI) on β-cell dysfunction. Among other chaperones, PDI was found to interact with hIAPP in human islet lysates. Furthermore, intrinsically recovered PDI levels were able to restore the effect of high glucose- and palmitate-induced β-cell dysfunction by increasing 3.9-fold the glucose-stimulated insulin secretion levels and restoring insulin content up to basal control values. Additionally, PDI transduction decreased induced apoptosis by glucolipotoxic conditions. This approach could reveal a new therapeutic target and aid in the development of strategies to improve β-cell dysfunction in type 2 diabetic patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Unexpected immunoresponse to Gal and APA antigens in diabetic type 1 patients receiving neonatal pig islets after 6 years.

    Science.gov (United States)

    Valdés-González, Rafael A; Dorantes, Luis M; Garibay, G Nayely; Bracho-Blanchet, Eduardo; Dávila-Pérez, Roberto; Terán, Luis; Ormsby, Christopher E; Ayala-Sumuano, Jorge-Tonatiuh; Copeman, Laura; White, David J G

    2007-05-01

    Cotransplantation of porcine islets and Sertoli cells into preimplanted subcutaneous devices improve metabolic control in type 1 diabetic patients, and survive grafted for more than 4 years. We report here, further assessment of the endocrine and porcine nature of the surviving cells and the immune responses elicited toward Gal alpha(1,3)-Gal beta(1,4)-GlcNAc (Gal) antigen in patients who received a second and third transplants. No immunosuppressive drugs were administered. We were able to immunostain insulin- and glucagon-positive cells in all biopsies of patients and Sertoli cell markers in 60.9% of biopsies. Additionally, all biopsies tested, amplified the porcine COII gene. Patients demonstrated an increase in antipig antibodies in response to the first transplant with a decreasing response toward the second and third transplants. In all transplants, the IgG levels promptly returned to basal values after 3-4 months. The long-term survival of porcine cells and the reduced humoral immune response to multiple transplants indicate a form of tolerance. We have not been able to find CD25-positive cells, indicating that it is probably an immune accommodation of the graft.

  13. Fibrillar dimer formation of islet amyloid polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Chi-cheng [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); de Pablo, Juan J. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-05-08

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 – 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 – 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  14. Fibrillar dimer formation of islet amyloid polypeptides

    Science.gov (United States)

    Chiu, Chi-cheng; de Pablo, Juan J.

    2015-09-01

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 - 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 - 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  15. 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.

  16. Carinal transplantation.

    OpenAIRE

    Ueda, H; Shirakusa, T

    1992-01-01

    BACKGROUND: Current techniques of management of carinal lesions are not always satisfactory. Carinal transplantation, if feasible, would be valuable in certain circumstances. METHODS AND RESULTS: Carinal transplantation experiments were performed in dogs. In early cross transplant experiments there were problems in controlling ventilation and in obtaining satisfactory anastomoses, and the animals failed to live for even a few days. In seven subsequent experiments the carinal graft was removed...

  17. ORIGINAL ARTICLES Islet neogenesis is stimulated by brief ...

    African Journals Online (AJOL)

    m oper~tion. The animals were. ... New therapies are therefore required to stem this islet depletion and restore pancreatic function. ... destroyed beta cells, Understanding the mechanism by which the pancreas can be stimulated to increase ...

  18. Assimilating Dokdo: The Islets in Korean Everyday Life

    Directory of Open Access Journals (Sweden)

    Brandon Palmer

    2016-03-01

    Full Text Available Sovereignty over the Tokto Islets is heatedly contested between South Korea and Japan. The Korean government and citizenry have responded to this dispute by inserting the islets into their national collective memory in multifarious ways in an attempt to strengthen their nation’s claim to Tokto. The islets are included in the material culture and public memory of the nation in ways that make them part of everyday life for millions of Koreans. Korea’s claim to Tokto is currently taught in schools, presented in museums, found in popular songs, and exploited by businesses for profit. The deeper Tokto becomes entrenched in Korean society, the less likely a compromise can be reached with Japan over the islets.

  19. Liver Transplant

    Science.gov (United States)

    ... Nutrition Clinical Trials Primary Biliary Cholangitis Definition & Facts Symptoms & Causes Diagnosis Treatment Eating, Diet, & Nutrition Clinical Trials Wilson Disease Liver Transplant View or Print All Sections Definition & ...

  20. Islet-cell dysfunction induced by glucocorticoid treatment

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  1. Cryopreserved neonatal hepatocytes may be a source for transplantation: Evaluation of functionality toward clinical use.

    Science.gov (United States)

    Lee, Charlotte A; Dhawan, Anil; Iansante, Valeria; Lehec, Sharon; Khorsandi, Shirin E; Filippi, Celine; Walker, Simon; Fernandez-Dacosta, Raquel; Heaton, Nigel; Bansal, Sanjay; Mitry, Ragai R; Fitzpatrick, Emer

    2018-03-01

    Neonatal livers are a potential source of good-quality hepatocytes for clinical transplantation. We compared viability and function of neonatal hepatocytes (NHs) and adult hepatocytes (AHs) and report their clinical use both intraportally and in alginate microbeads. Following isolation from donor livers, hepatocyte function was assessed using albumin, alpha-1-antitrypsin, and factor VII. Metabolic function was investigated by measuring resorufin conjugation, ammonia metabolism, uridine diphosphate glucuronosyltransferase enzyme activity, and cytochrome P450 (CYP) function following induction. Activation of the instant blood-mediated inflammatory reaction by NHs and AHs was investigated using an in vitro blood perfusion model, and tissue factor expression was analyzed using real-time polymerase chain reaction (RT-PCR). Clinical hepatocyte transplantation (HT) was undertaken using standard protocols. Hepatocytes were isolated from 14 neonatal livers, with an average viability of 89.4% ± 1.8% (mean ± standard error of the mean) and average yield of 9.3 × 10 6 ± 2.0 × 10 6 cells/g. Hepatocytes were isolated from 14 adult livers with an average viability of 78.6% ± 2.4% and yield 2.2 × 10 6 ± 0.5 × 10 5 cells/g. NHs had significantly higher viability after cryopreservation than AHs, with better attachment efficiency and less plasma membrane leakage. There were no differences in albumin, alpha-1-antitrypsin, and factor VII synthesis between NHs and AHs (P > 0.05). Neonatal cells had inducible phase 1 enzymes as assessed by CYP function and functional phase 2 enzymes, in which activity was comparable to AHs. In an in vitro blood perfusion model, AHs elicited increased thrombus formation with a greater consumption of platelets and white cells compared with NHs (28.3 × 10 9 versus 118.7 × 10 9 and 3.3 × 10 9 versus 6.6 × 10 9 ; P < 0.01). Intraportal transplantation and intraperitoneal transplantation of alginate encapsulated hepatocytes was safe, and

  2. Three-yr follow-up of a type 1 diabetes mellitus patient with an islet xenotransplant.

    Science.gov (United States)

    Valdés-González, R A; White, D J G; Dorantes, L M; Terán, L; Garibay-Nieto, G N; Bracho-Blanchet, E; Dávila-Pérez, R; Evia-Viscarra, L; Ormsby, C E; Ayala-Sumuano, J T; Silva-Torres, M L; Ramírez-González, B

    2007-01-01

    In order to alleviate the shortage of human donors, the use of porcine islets of Langerhans for xenotransplantation in diabetic patients has been proposed as a solution. To overcome rejection, we have developed a procedure for protecting the islets by combining them with Sertoli cells and placing them in a novel subcutaneous device, that generates an autologous collagen covering. A type 1 diabetic woman was closely monitored for 10 months, and then transplanted in two devices with two months of difference and a third time after 22 months. Here we present a three-yr follow-up. The close monitoring induced a rapid decrease in exogenous insulin requirements, which stabilized between 19 and 28 IU/d for nine months. After transplantation, the requirements reduced further to below 6 IU/d and for some weeks she was insulin free. Glycosylated hemoglobin levels decreased concomitantly. Porcine insulin could be detected in the serum after a glucose challenge and insulin positive cells inside a removed device after two yr. No complications have arisen and no porcine endogenous retrovirus infection has been detected through PCR and RT-PCR. This case demonstrates the feasibility of using the xenotransplantation of porcine cells to alleviate metabolic complications and insulin requirements in type 1 diabetic patients.

  3. The International Xenotransplantation Association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes--chapter 1: Key ethical requirements and progress toward the definition of an international regulatory framework.

    Science.gov (United States)

    Cozzi, Emanuele; Tallacchini, Mariachiara; Flanagan, Enda B; Pierson, Richard N; Sykes, Megan; Vanderpool, Harold Y

    2009-01-01

    The outstanding results recently obtained in islet xenotransplantation suggest that porcine islet clinical trials may soon be scientifically appropriate. Before the initiation of such clinical studies, however, it is essential that a series of key ethical and regulatory conditions are satisfied. As far as ethics is concerned, the fundamental requirements have been previously reported in a position paper of the Ethics Committee of the International Xenotransplantation Association. These include aspects related to the selection of adequately informed, appropriate recipients; animal breeding and welfare; safety issues and the need for a favorable risk/benefit assessment based on strong efficacy data in relevant xenotransplantation studies in the primate. As most diabetic patients are not at risk of short-term mortality without islet transplantation, only a small subset of patients could currently be considered for any type of islet transplant. However, there are potential advantages to xenotransplantation that could result in a favorable benefit-over-harm determination for islet xenotransplantation in this subpopulation and ultimately in a broader population of diabetic patients. With regard to regulatory aspects, the key concepts underlying the development of the regulatory models in existence in the United States, Europe and New Zealand are discussed. Each of these models provides an example of a well-defined regulatory approach to ensure the initiation of well-regulated and ethically acceptable clinical islet xenotransplantation trials. At this stage, it becomes apparent that only a well-coordinated international effort such as that initiated by the World Health Organization, aimed at harmonizing xenotransplantation procedures according to the highest ethical and regulatory standards on a global scale, will enable the initiation of clinical xenotransplantation trials under the best auspices for its success and minimize any risk of failure.

  4. Corneal Transplantation

    DEFF Research Database (Denmark)

    Hjortdal, Jesper Østergaard

    Corneal transplantation has been performed for more than 100 years. Until 15 years ago the state-of-the art type of transplantation was penetrating keratoplasty, but since the start of this millennium, newly designed surgical techniques have developed considerably. Today, the vast majority of ker...

  5. Heart transplant

    Science.gov (United States)

    ... hospital for 7 to 21 days after a heart transplant. The first 24 to 48 hours will likely be in ... follow your self-care instructions. Biopsies of the heart muscle are ... after transplant, and then less often after that. This helps ...

  6. Lung transplant

    Science.gov (United States)

    ... transplant surgery include: You are placed on the heart-lung machine. One or both of your lungs are removed. For people who are having a double lung transplant, most or all of the steps from the first side are completed before the second side is ...

  7. Pancreatic islet cell reaggregation systems: efficiency of cell reassociation and endocrine cell topography of rat islet-like aggregates.

    Science.gov (United States)

    Matta, S G; Wobken, J D; Williams, F G; Bauer, G E

    1994-07-01

    Single cells isolated from rat islets of Langerhans were cultured under conditions that support reassociation into islet-like aggregates. Comparisons were made of enzymatic methods of islet dissociation, rotational or static culture conditions, and culture at basal or stimulatory glucose concentrations. Over a period of 4 days the aggregates progressed through three stages of organization: cell coalescence to cellular chains, rearrangement of chains into small spheroids, and growth of spheroids. The numerical yield of aggregates was optimum after islets were dissociated with dispase. Culture under rotation resulted in the production of more aggregates of significantly larger diameter than under static conditions. Medium glucose concentrations of 4 and 11 mM supported cell reassociation under rotator culture, but no aggregation occurred under static culture at the basal (4 mM) glucose level. Aggregates resulting from 4-day rotator culture exhibited endocrine cell distributions similar to intact islets. Islet aggregates released insulin in response to glucose, but nonaggregated cells, maintained in culture, did not. The present comparisons reveal significant variability in the cellular composition, rate of formation, and yield of aggregates, and suggest that the methodology for producing aggregates should be carefully considered in experimental design.

  8. Carinal transplantation.

    Science.gov (United States)

    Ueda, H; Shirakusa, T

    1992-01-01

    BACKGROUND: Current techniques of management of carinal lesions are not always satisfactory. Carinal transplantation, if feasible, would be valuable in certain circumstances. METHODS AND RESULTS: Carinal transplantation experiments were performed in dogs. In early cross transplant experiments there were problems in controlling ventilation and in obtaining satisfactory anastomoses, and the animals failed to live for even a few days. In seven subsequent experiments the carinal graft was removed from one dog and transplanted into a second dog. Two dogs lived for over four months with immunosuppression. CONCLUSION: The results suggest that carinal transplantation can succeed if (1) the calibre of the graft is matched with that of the recipient; (2) there is an abundant blood supply to the graft; (3) appropriate immunosuppression is provided; (4) ventilation is adequate during surgery. Images PMID:1465758

  9. Treatment of Diabetes with Encapsulated Islets

    NARCIS (Netherlands)

    de Vos, Paul; Spasojevic, Milica; Faas, Marijke M.; Pedraz, JL; Orive, G

    2010-01-01

    Cell encapsulation has been proposed for the treatment of a wide variety of diseases since it allows for transplantation of cells in the absence of undesired immunosuppression. The technology has been proposed to be a solution for the treatment of diabetes since it potentially allows a mandatory

  10. Fetal endocannabinoids orchestrate the organization of pancreatic islet microarchitecture.

    Science.gov (United States)

    Malenczyk, Katarzyna; Keimpema, Erik; Piscitelli, Fabiana; Calvigioni, Daniela; Björklund, Peyman; Mackie, Kenneth; Di Marzo, Vincenzo; Hökfelt, Tomas G M; Dobrzyn, Agnieszka; Harkany, Tibor

    2015-11-10

    Endocannabinoids are implicated in the control of glucose utilization and energy homeostasis by orchestrating pancreatic hormone release. Moreover, in some cell niches, endocannabinoids regulate cell proliferation, fate determination, and migration. Nevertheless, endocannabinoid contributions to the development of the endocrine pancreas remain unknown. Here, we show that α cells produce the endocannabinoid 2-arachidonoylglycerol (2-AG) in mouse fetuses and human pancreatic islets, which primes the recruitment of β cells by CB1 cannabinoid receptor (CB1R) engagement. Using subtractive pharmacology, we extend these findings to anandamide, a promiscuous endocannabinoid/endovanilloid ligand, which impacts both the determination of islet size by cell proliferation and α/β cell sorting by differential activation of transient receptor potential cation channel subfamily V member 1 (TRPV1) and CB1Rs. Accordingly, genetic disruption of TRPV1 channels increases islet size whereas CB1R knockout augments cellular heterogeneity and favors insulin over glucagon release. Dietary enrichment in ω-3 fatty acids during pregnancy and lactation in mice, which permanently reduces endocannabinoid levels in the offspring, phenocopies CB1R(-/-) islet microstructure and improves coordinated hormone secretion. Overall, our data mechanistically link endocannabinoids to cell proliferation and sorting during pancreatic islet formation, as well as to life-long programming of hormonal determinants of glucose homeostasis.

  11. Organ Transplantation

    Science.gov (United States)

    ... here for a deeper conversation on this topic led by Hastings Director of Research Josephine Johnston. Sorry, ... accept people without insurance. Transplant teams rarely consider anyone over 75 years of age. Some centers exclude ...

  12. Hair Transplants

    Science.gov (United States)

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Hair Transplants Before (left) and after (right) - top ...

  13. Cornea Transplant

    Science.gov (United States)

    ... Swelling of the cornea Signs and symptoms of cornea rejection In some cases, your body's immune system ... the risks of the procedure. Finding a donor cornea Most corneas used in cornea transplants come from ...

  14. Liver Transplant

    Science.gov (United States)

    ... Legacy Society Make Gifts of Stock Donate Your Car Personal Fundraising Partnership & Support Share Your Story Spread the Word Give While You Shop Contact Us Donate Now Liver Transplant Back In ...

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. Preservation of beta cell function in adult human pancreatic islets for several months in vitro

    DEFF Research Database (Denmark)

    Brunstedt, J; Andersson, A; Frimodt-Møller, C

    1979-01-01

    Islets of Langerhans were isolated from four human kidney donors, aged 16 to 21 years by the collagenase method described for isolation of rodent islets. So far the human islets have been kept in tissue culture, without attachment, in medium RPMI 1640 supplemented with 10% calf serum for more than...

  20. 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...

  1. Abnormal islet sphingolipid metabolism in type 1 diabetes

    DEFF Research Database (Denmark)

    Holm, Laurits J; Krogvold, Lars; Hasselby, Jane P

    2018-01-01

    treated NOD mice with fenofibrate, a known activator of sulfatide biosynthesis, to evaluate the effect on experimental autoimmune diabetes development. RESULTS: We found reduced amounts of sulfatide, 23% of the levels in control participants, in pancreatic islets of individuals with newly diagnosed type 1...... diabetes. These gene polymorphisms correlated with the degree of cellular islet autoimmunity in a cohort of individuals with type 1 diabetes. Finally, using fenofibrate, which activates sulfatide biosynthesis, we completely prevented diabetes in NOD mice and even reversed the disease in half of otherwise...... of human type 1 diabetes and whether increasing the levels of the sphingolipid sulfatide would prevent models of diabetes in NOD mice. METHODS: We examined the amount and distribution of sulfatide in human pancreatic islets by immunohistochemistry, immunofluorescence and electron microscopy...

  2. The combination of anti-NKG2D and CTLA-4 Ig therapy prolongs islet allograft survival in a murine model.

    Science.gov (United States)

    Pawlick, R; Gala-Lopez, B; Pepper, A R; McCall, M; Ziff, O; Shapiro, A M J

    2014-10-01

    Islet transplantation is an effective means of treating severe type 1 diabetes in patients with life-threatening hypoglycemia. Improvements in glycemic control with correction of HbA1C enhance quality of life irrespective of insulin independence. By antagonizing the Natural Killer Group 2, member D (NKG2D) receptor expression on NK and CD8+ T cells, in combination with blocking CTLA-4 binding sites, we demonstrate a significant delay of graft rejection in islet allotransplant. Anti-NKG2D combined with CTLA-4 Ig (n = 15) results in prolonged allograft survival, with 84.6 ± 10% of the recipients displaying insulin independence compared to controls (n = 10, p < 0.001). The effect of combination therapy on graft survival is superior to treatments alone (CTLA-4 Ig vs. combination p = 0.024, anti-NKG2D vs. combination p < 0.001) indicating an interaction between these pathways. In addition, combination treatment also improves glucose tolerance when compared to controls (n = 10, p = 0.018). Histologically, NKG2D+ cells were significantly decreased within the allograft after 7 days of combination treatment (n = 6, p = 0.029). T cell proliferation was significantly reduced with anti-NKG2D therapy and CD8+ T cell daughter fractions were also significantly decreased with mAb and combination treatment when measured by in vitro mixed lymphocyte reaction (n = 5, p = 0.015, p = 0.005 and p = 0.048). These results demonstrate that inhibition of NKG2D receptors and costimulatory pathways enhance islet allograft survival. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

  3. Kidney-Pancreas Transplant

    Science.gov (United States)

    ... Menu Menu Search Home Prevention Kidney Disease Patients Organ Donation & Transplantation Professionals Events Advocacy Donate A to Z Health ... Tests for Transplant Care After Kidney Transplant Common Organ Donation and Transplantation Terms The National Kidney Foundation (NKF) is the ...

  4. Abnormal islet sphingolipid metabolism in type 1 diabetes.

    Science.gov (United States)

    Holm, Laurits J; Krogvold, Lars; Hasselby, Jane P; Kaur, Simranjeet; Claessens, Laura A; Russell, Mark A; Mathews, Clayton E; Hanssen, Kristian F; Morgan, Noel G; Koeleman, Bobby P C; Roep, Bart O; Gerling, Ivan C; Pociot, Flemming; Dahl-Jørgensen, Knut; Buschard, Karsten

    2018-04-18

    Sphingolipids play important roles in beta cell physiology, by regulating proinsulin folding and insulin secretion and in controlling apoptosis, as studied in animal models and cell cultures. Here we investigate whether sphingolipid metabolism may contribute to the pathogenesis of human type 1 diabetes and whether increasing the levels of the sphingolipid sulfatide would prevent models of diabetes in NOD mice. We examined the amount and distribution of sulfatide in human pancreatic islets by immunohistochemistry, immunofluorescence and electron microscopy. Transcriptional analysis was used to evaluate expression of sphingolipid-related genes in isolated human islets. Genome-wide association studies (GWAS) and a T cell proliferation assay were used to identify type 1 diabetes related polymorphisms and test how these affect cellular islet autoimmunity. Finally, we treated NOD mice with fenofibrate, a known activator of sulfatide biosynthesis, to evaluate the effect on experimental autoimmune diabetes development. We found reduced amounts of sulfatide, 23% of the levels in control participants, in pancreatic islets of individuals with newly diagnosed type 1 diabetes, which were associated with reduced expression of enzymes involved in sphingolipid metabolism. Next, we discovered eight gene polymorphisms (ORMDL3, SPHK2, B4GALNT1, SLC1A5, GALC, PPARD, PPARG and B4GALT1) involved in sphingolipid metabolism that contribute to the genetic predisposition to type 1 diabetes. These gene polymorphisms correlated with the degree of cellular islet autoimmunity in a cohort of individuals with type 1 diabetes. Finally, using fenofibrate, which activates sulfatide biosynthesis, we completely prevented diabetes in NOD mice and even reversed the disease in half of otherwise diabetic animals. These results indicate that islet sphingolipid metabolism is abnormal in type 1 diabetes and suggest that modulation may represent a novel therapeutic approach. The RNA expression data is

  5. Current perspectives in transplant medicine: hypothermic oxygenated perfusion

    Directory of Open Access Journals (Sweden)

    Michel SG

    2016-11-01

    Full Text Available Sebastian G Michel,1 Joren C Madsen2,3 1Department of Cardiac Surgery, Ludwig-Maximilians-University, Munich, Germany; 2Department of Surgery, Center for Transplantation Sciences, 3Division of Cardiac Surgery, Department of Surgery, Massachusetts General Hospital, Boston, MA, USA Abstract: The purpose of this review was to provide an update on hypothermic oxygenated perfusion as a preservation technique for whole organ allografts. Clinical and experimental data in heart, lung, liver, kidney, and pancreas/islet transplantation are summarized with a special emphasis on marginal donors and donation after circulatory death. The rationale behind hypothermic machine perfusion as well as its advantages and disadvantages compared to conventional cold storage and the competing technique, normothermic machine perfusion, are reviewed. Keywords: organ transplantation, organ preservation, hypothermic perfusion

  6. Carbon monoxide and pancreatic islet blood flow in the rat: inhibition of haem oxygenase does not affect islet blood perfusion.

    Science.gov (United States)

    Carlsson, P-O; Bodin, B; Andersson, A; Jansson, L

    2006-01-01

    To determine whether carbon monoxide, a known gaseous vasorelaxator, affects pancreatic islet blood flow in rats. Sprague-Dawley rats were anaesthetized with thiobutabarbital and injected intravenously with the haem oxygenase inhibitor tin-protoporphyrin IX dichloride (SnPP; 4, 10 or 20 mg/kg body-weight). After 15 min, blood flow measurements were performed using a microsphere technique. There was a slight increase in mean arterial blood pressure with the highest dose of SnPP. No effects on total pancreatic, islet, duodenal, colonic, renal or adrenal blood flow were seen with any of the applied doses. The findings of this study suggest that the haem oxygenase-carbon monoxide system is likely to be of limited importance in the regulation of blood perfusion to the pancreas, the islets of Langerhans or any of the other studied organs.

  7. 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

    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...... techniques for the large scale isolation of functionally intact human islets....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-05

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  10. Ultrastructural studies of time-course and cellular specificity of interleukin-1 mediated islet cytotoxicity

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Egeberg, J; Nerup, J

    1987-01-01

    Previous electron-microscopic studies of isolated islets of Langerhans exposed to the monokine interleukin-1 for 7 days have indicated that interleukin-1 is cytotoxic to all islet cells. To study the time-course and possible cellular specificity of interleukin-1 cytotoxicity to islets exposed...... to interleukin-1 for short time periods, isolated rat or human islets were incubated with or without 25 U/ml highly purified human interleukin-1 for 24 h. Samples of rat islets were taken after 5 min, 30 min, 1, 2, 4, 6, 8, 10, 12, 16, 20 and 24 h and samples of human islets after 5 min, 30 min and 24 h...... of incubation and examined by electron microscopy in a blinded fashion. Already after 30 min, accumulation of opaque intracytoplasmic bodies without apparent surrounding membranes, and autophagic vacuoles were seen in about 20% of the beta cells examined in rat islets exposed to interleukin-1. After 16 h...

  11. Rituximab selectively suppresses specific islet antibodies.

    Science.gov (United States)

    Yu, Liping; Herold, Kevan; Krause-Steinrauf, Heidi; McGee, Paula L; Bundy, Brian; Pugliese, Alberto; Krischer, Jeff; Eisenbarth, George S

    2011-10-01

    The TrialNet Study Group evaluated rituximab, a B-cell-depleting monoclonal antibody, for its effect in new-onset patients with type 1A diabetes. Rituximab decreased the loss of C-peptide over the first year of follow-up and markedly depleted B lymphocytes for 6 months after administration. This article analyzes the specific effect of rituximab on multiple islet autoantibodies. A total of 87 patients between the ages of 8 and 40 years received either rituximab or a placebo infusion weekly for four doses close to the onset of diabetes. Autoantibodies to insulin (IAAs), GAD65 (GADAs), insulinoma-associated protein 2 (IA2As), and ZnT8 (ZnT8As) were measured with radioimmunoassays. The primary outcome for this autoantibody analysis was the mean level of autoantibodies during follow-up. Rituximab markedly suppressed IAAs compared with the placebo injection but had a much smaller effect on GADAs, IA2As, and ZnT8As. A total of 40% (19 of 48) of rituximab-treated patients who were IAA positive became IAA negative versus 0 of 29 placebo-treated patients (P IAAs were markedly suppressed by rituximab in all patients for 1 year and for four patients as long as 3 years despite continuing insulin therapy. Independent of rituximab treatment, the mean level of IAAs at study entry was markedly lower (P = 0.035) for patients who maintained C-peptide levels during the first year of follow-up in both rituximab-treated and placebo groups. A single course of rituximab differentially suppresses IAAs, clearly blocking IAAs for >1 year in insulin-treated patients. For the patients receiving insulin for >2 weeks prior to rituximab administration, we cannot assess whether rituximab not only blocks the acquisition of insulin antibodies induced by insulin administration and/or also suppresses preformed insulin autoantibodies. Studies in prediabetic non-insulin-treated patients will likely be needed to evaluate the specific effects of rituximab on levels of IAAs.

  12. c-Jun N-terminal kinase 1 defective CD4+CD25+FoxP3+ cells prolong islet allograft survival in diabetic mice.

    Science.gov (United States)

    Tripathi, Deepak; Cheekatla, Satyanarayana S; Paidipally, Padmaja; Radhakrishnan, Rajesh Kumar; Welch, Elwyn; Thandi, Ramya Sivangala; Tvinnereim, Amy R; Vankayalapati, Ramakrishna

    2018-02-19

    CD4+CD25+FoxP3+ cells (Tregs) inhibit inflammatory immune responses to allografts. Here, we found that co-transplantation of allogeneic pancreatic islets with Tregs that are defective in c-Jun N-terminal kinase 1 (JNK1) signaling prolongs islet allograft survival in the liver parenchyma of chemically induced diabetic mice (CDM). Adoptively transferred JNK1 -/- but not wild-type (WT) Tregs survive longer in the liver parenchyma of CDM. JNK1 -/- Tregs are resistant to apoptosis and express anti-apoptotic molecules. JNK1 -/- Tregs express higher levels of lymphocyte activation gene-3 molecule (LAG-3) on their surface and produce higher amounts of the anti-inflammatory cytokine interleukin (IL)-10 compared with WT Tregs. JNK1 -/- Tregs inhibit liver alloimmune responses more efficiently than WT Tregs. JNK1 -/- but not WT Tregs are able to inhibit IL-17 and IL-21 production through enhanced LAG-3 expression and IL-10 production. Our study identifies a novel role of JNK1 signaling in Tregs that enhances islet allograft survival in the liver parenchyma of CDM.

  13. Cadaveric transplantation.

    Directory of Open Access Journals (Sweden)

    Gokal R

    1993-10-01

    Full Text Available Transplantation is already the optimum treatment for terminal renal failure. Donor organ shortage means that there are large number of patients on dialysis awaiting this treatment. This has in some countries led to unacceptable unscrupulous practices of live non-related graft donation. The outcome of graft and patient after transplantation has improved significantly based on a better understanding of immunopathology, immunosuppression and tissue typing. The future is promising and xenografting may well solve the organ shortage but undoubtedly will raise other issues.

  14. Pancreas transplantation

    International Nuclear Information System (INIS)

    Snider, J.F.; Hunter, D.W.; Castaneda-Zuniga, W.R.; Letourneau, J.G.

    1989-01-01

    Pancreas transplantation can be complicated by vascular thrombosis, stenosis, or anastomotic leak, complications that predispose to transplant pancreatectomy. The relative roles of noninvasive radiologic studies in such vascular complications have been correlated with angiographic or pathologic data. The results of 54 scintigraphic studies, 25 CT studies, 16 sonograms, and 23 color Doppler examinations have been correlated with those of 40 angiograms and 28 pathologic studies in a population of 185 recipients. CT (sensitivity, 100%; specificity, 75%; accuracy, 92%) and US (sensitivity, 88%; specificity, 80%; accuracy, 85%) were most helpful in noninvasive screening for vascular complications, while angiography remains nearly definite in the radiographic diagnosis of these problems

  15. Immunohistochemical analysis of pancreatic islets of platypus (Ornithorhynchus anatinus) and echidna (Tachyglossus aculeatus ssp.).

    Science.gov (United States)

    He, Chuan; Myers, Mark A; Forbes, Briony E; Grützner, Frank

    2015-04-01

    Monotremes have undergone remarkable changes to their digestive and metabolic control system; however, the monotreme pancreas remains poorly characterized. Previous work in echidna demonstrated the presence of pancreatic islets, but no information is available for platypus and the fine structure has not been described for either monotreme. Based on our recent finding that monotremes lack the ghrelin gene, which is expressed in mouse and human pancreatic islets, we investigated the structure of monotreme islets in more detail. Generally, as in birds, the islets of monotremes were smaller but greater in number compared with mouse. β-cells were the most abundant endocrine cell population in platypus islets and were located peripherally, while α-cells were observed both in the interior and periphery of the islets. δ-cells and pancreatic polypeptide (PP)-cells were mainly found in the islet periphery. Distinct PP-rich (PP-lobe) and PP-poor areas (non-PP-lobe) are present in therian mammals, and we identified these areas in echidna but not platypus pancreas. Interestingly, in some of the echidna islets, α- and β-cells tended to form two poles within the islets, which to our knowledge is the first time this has been observed in any species. Overall, monotreme pancreata share the feature of consisting of distinct PP-poor and PP-rich islets with other mammals. A higher number of islets and α- or β-cell only islets are shared between monotremes and birds. The islets of monotremes were larger than those of birds but smaller compared with therian mammals. This may indicate a trend of having fewer larger islets comprising several endocrine cell types during mammalian evolution. © 2015 Anatomical Society.

  16. Islet neogenesis is stimulated by brief occlusion of the main ...

    African Journals Online (AJOL)

    The animals were killed 56 days post .occlusion, and the pancreata excised and fiXed tor histological analysis. Body, pancreatic and hepatic weights were .noted at termination. and serum was taken for analysis. The endocrine-to-exocrine. ratio was calculated and the number of endocrine cells in eacn islet from the ...

  17. Pancreatic islet-cell viability, functionality and oxidative status ...

    Indian Academy of Sciences (India)

    Unknown

    lar) in case of lean and obese mice (Dalpe-Scott et al. 1983). Antibiotics also show concentration dependant effect on the islet functionality. Injection of tetracycline hydrochloride at the dose of 25 mg/kg body weight in mice did not change the functional activity of the β-cells and the rate of insulin formation and secretion for ...

  18. Pancreatic islet regeneration: Therapeutic potential, unknowns and controversy

    Directory of Open Access Journals (Sweden)

    Ingrid L. Cockburn

    2015-07-01

    Full Text Available Glucose homeostasis in mammals is primarily maintained by the insulin-secreting β-cells contained within pancreas-resident islets of Langerhans. Gross disruption of this glucose regulation as a result of pancreatic dysfunction frequently results in diabetes, which is currently a major health concern in South Africa, as well as globally. For many years, researchers have realised that the pancreas, and specifically the islets of Langerhans, have a regenerative capacity, as islet mass has frequently been shown to increase following induced pancreatic injury. Given that gross β-cell loss contributes significantly to the pathogenesis of both type 1 and type 2 diabetes, endogenous pancreatic islet regeneration has been investigated extensively as a potential β-cell replacement therapy for diabetes. From the extensive research conducted on pancreatic regeneration, opposing findings and opinions have arisen as to how, and more recently even if, pancreatic regeneration occurs following induced injury. In this review, we outline and discuss the three primary mechanisms by which pancreatic regeneration is proposed to occur: neogenesis, β-cell replication and transdifferentiation. We further explain some of the advanced techniques used in pancreatic regeneration research, and conclude that despite the technologically advanced research tools available to researchers today, the mechanisms governing pancreatic regeneration may remain elusive until more powerful techniques are developed to allow for real-time, live-cell assessment of morphology and gene expression within the pancreas.

  19. Epithelial to mesenchymal transition in human endocrine islet cells.

    Directory of Open Access Journals (Sweden)

    José Luis Moreno-Amador

    Full Text Available β-cells undergo an epithelial to mesenchymal transition (EMT when expanded in monolayer culture and give rise to highly proliferative mesenchymal cells that retain the potential to re-differentiate into insulin-producing cells.To investigate whether EMT takes place in the endocrine non-β cells of human islets.Human islets isolated from 12 multiorgan donors were dissociated into single cells, purified by magnetic cell sorting, and cultured in monolayer.Co-expression of insulin and the mesenchymal marker vimentin was identified within the first passage (p1 and increased subsequently (insulin+vimentin+ 7.2±6% at p1; 43±15% at p4. The endocrine non-β-cells did also co-express vimentin (glucagon+vimentin+ 59±1.5% and 93±6%, somatostatin+vimentin+ 16±9.4% and 90±10% at p1 and p4 respectively; PP+vimentin+ 74±14% at p1; 88±12% at p2. The percentage of cells expressing only endocrine markers was progressively reduced (0.6±0.2% insulin+, 0.2±0.1% glucagon+, and 0.3±0.2% somatostatin+ cells at p4, and 0.7±0.3% PP+ cells at p2. Changes in gene expression were also indicated of EMT, with reduced expression of endocrine markers and the epithelial marker CDH-1 (p<0.01, and increased expression of mesenchymal markers (CDH-2, SNAI2, ZEB1, ZEB2, VIM, NT5E and ACTA2; p<0.05. Treatment with the EMT inhibitor A83-01 significantly reduced the percentage of co-expressing cells and preserved the expression of endocrine markers.In adult human islets, all four endocrine islet cell types undergo EMT when islet cells are expanded in monolayer conditions. The presence of EMT in all islet endocrine cells could be relevant to design of strategies aiming to re-differentiate the expanded islet cells towards a β-cell phenotype.

  20. No evidence of porcine endogenous retrovirus in patients with type 1 diabetes after long-term porcine islet xenotransplantation.

    Science.gov (United States)

    Valdes-Gonzalez, Rafael; Dorantes, Luis M; Bracho-Blanchet, Eduardo; Rodríguez-Ventura, Ana; White, D J G

    2010-02-01

    Xenotransplantation is a promising alternative for donor shortage to ameliorate physiologic and metabolic disorders. The major concern for xenotransplant is the risk of zoonosis mainly by the porcine endogenous retrovirus (PERV), presentation in the piglet genome. Twenty-three patients with type 1 diabetes were transplanted with porcine islets using collagen-generating devices which were implanted subcutaneously in the anterior wall of the abdomen. Clinical characteristics and metabolic tests were recorded in each visit. They were tested for PERV using PCR and RT-PCR from blood pretransplantation and every 3 months during a 4.6- to 8-year follow-up after their first xenotransplant. Tests by PCR of every DNA sample (780 samples) revealed that there was no PERV infection in the DNA of white cells. No evidence of PERV activation was found in this group of patients with type 1 diabetes during clinical long-term follow-up. (c) 2009 Wiley-Liss, Inc.

  1. Maternal vitamin A deficiency during pregnancy affects vascularized islet development.

    Science.gov (United States)

    Chien, Chiao-Yun; Lee, Hsuan-Shu; Cho, Candy Hsin-Hua; Lin, Kuo-I; Tosh, David; Wu, Ruei-Ren; Mao, Wan-Yu; Shen, Chia-Ning

    2016-10-01

    Vitamin A deficiency is known to affect 20 million pregnant women worldwide. However, the prenatal effects of maternal vitamin A deficiency on pancreas development have not been clearly determined. The present study examined how maternal vitamin A deficiency affects fetal islet development. Vitamin A-deficient mice were generated by feeding female mice with a chemically defined diet lacking vitamin A prior to mating as well as during pregnancy. We found that maternal vitamin A deficiency during pregnancy affected fetal pancreas development. Although the exocrine differentiation appeared normal, development of islet tissue was impaired. In the pancreas of neonatal mice, only a few endocrine cell clusters were formed, and these cell clusters lacked capillary endothelial cells. To further determine how vitamin A metabolites, such as retinoic acid, regulate vascularized islet development, ex vivo culture of embryonic pancreas either in the presence of 4-diethylaminobenzaldehyde (DEAB; an inhibitor of retinaldehyde dehydrogenase), all-trans retinoic acid (atRA) or retinoic acid receptor agonist (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthylenyl)-1-propenyl] benzoic acid (TTNPB) was carried out. We found that the addition of DEAB blocked vascularization and suppressed β-cell differentiation. Conversely, atRA or TTNPB promoted β-cell differentiation accompanied by enhanced expression of vascular basement component, laminin. We further demonstrated that atRA regulated vascularization via upregulating vascular endothelial growth factor-A (VEGF-A) secretion in embryonic pancreas and treatment with VEGF-A was able to partially rescue vascularization and β-cell differentiation in DEAB-treated embryonic pancreas cultures. The findings explain why maternal vitamin A deficiency affects fetal islet development and support an essential role of retinoid signaling in regulating vascularized islet development. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Eyebrow transplantation.

    Science.gov (United States)

    Goldman, G D

    2001-04-01

    Reconstruction of the eyebrow has historically been accomplished with temporal scalp pedicle flap formation or free composite scalp grafts. These two techniques may be associated with substantial morbidity and a false, overly dense eyebrow appearance. Hair transplantation of the eyebrows has been described with excellent results, but is relatively underreported in the literature. To determine whether modern techniques of micrograft hair transplantation can suitably re-create an aesthetic eyebrow in a case of iatrogenic eyebrow alopecia. A 33-year-old woman with iatrogenic eyebrow alopecia underwent four sessions of eyebrow micrograft hair transplantation to re-create both eyebrows. Suitable aesthetic eyebrows were re-created in a symmetric fashion with proper hair orientation. The process was time consuming and tedious, but highly effective. Eyebrow transplantation is a suitable alternative to pedicle flap formation and composite scalp grafting. It is a straightforward procedure that can be performed in the office under local anesthesia with minimal attendant morbidity. The result may be superior to that seen with more involved eyebrow replacement procedures.

  3. Intestine transplantation

    Directory of Open Access Journals (Sweden)

    Tadeja Pintar

    2011-02-01

    Conclusion: Intestine transplantation is reserved for patients with irreversible intestinal failure due to short gut syndrome requiring total paranteral nutrition with no possibility of discontinuation and loss of venous access for patient maintenance. In these patients complications of underlying disease and long-term total parenteral nutrition are present.

  4. Heart Transplantation

    Science.gov (United States)

    A heart transplant removes a damaged or diseased heart and replaces it with a healthy one. The healthy heart comes from a donor who has died. It is the last resort for people with heart failure when all other treatments have failed. The ...

  5. Trans-arterial xenotransplantation (Tx) of newborn porcine islet (NPI). A clinic trial for type I diabetes

    International Nuclear Information System (INIS)

    Wang Wei; Mo Zhaohui; Huang Zufa; Luo Xianming; Liu Sheng; Ye Bin; Li Bing; Liu Yingxin

    2002-01-01

    Objective: Liver is an important site to host transplanted islets, and implanting of islets by hepatic artery is simpler than by portal vein. Authors' study evaluated efficiency of the method and possible complication in a clinical setting. Methods: From October 1998 to June 2000, 4 type I diabetic patients received 4 x 10 6 (2 cases) and 8 x 10 6 (2 cases) of NPI through hepatic artery. Before Tx, all cases had the history with ketosis and acidosis. Exogenous insulin doses used for these cases were 25-48 units and their GHb was 9%-11%. After Tx, the NPI recipients were treated with immunosuppressants including cyclosporin 8 mg/kg for 12 months, cellcept 2 g/d for 25 days, and methylprednisolone 500 mg at 1 st day, then reduced to 50 mg for 3 days until to 10 mg for 1 month. Liver function and CD4/CD8 of the recipients were measured before and after Tx. Results: After Tx, the dose of exogenous insulin was increased to 60 mg due to methylprednisolone treatment. When methylprednisolone dose was decreased, the requirement for insulin was reduced to 32%-58% of the dose used before Tx. The reduction of required insulin for NPI recipients was proportional to the number of implanted NPI. In addition, GHb was also reduced to normal level (4%-6%) 3 months after Tx. No significant alterations of liver function and CD4 and CD8 in blood were observed after Tx. Conclusion: Trans-arterial intro-hepatic xenotransplantation of NPI is an efficient and safe therapeutic method for type I diabetes. Combination of cyclosporin, cellcept, and methylprednisolone is an effective immunosuppressive strategy for NPI xenograft transplantation

  6. Functional implications of long non-coding RNAs in the pancreatic islets of Langerhans

    Directory of Open Access Journals (Sweden)

    Lena eEliasson

    2014-07-01

    Full Text Available Type-2 diabetes (T2D is a complex disease characterized by insulin resistance in target tissues and impaired insulin release from pancreatic beta cells. As central tissue of glucose homeostasis, the pancreatic islet continues to be an important focus of research to understand the pathophysiology of the disease. The increased access to human pancreatic islets has resulted in improved knowledge of islet function, and together with advances in RNA sequencing and related technologies, revealed the transcriptional and epigenetic landscape of human islet cells. The discovery of thousands of long non-coding RNA (lncRNA transcripts highly enriched in the pancreatic islet and/or specifically-expressed in the beta-cells, points to yet another layer of gene regulation of many hitherto unknown mechanistic principles governing islet cell functions. Here we review fundamental islet physiology and propose functional implications of the lncRNAs in islet development and endocrine cell functions. We also take into account important differences between rodent and human islets in terms of morphology and function, and suggest how species-specific lncRNAs may partly influence gene regulation to define the unique phenotypic identity of an organism and the functions of its constituent cells. The implication of primate-specific lncRNAs in diabetes will be far-reaching in all aspects of diabetes research, but most importantly in the identification and development of novel targets to improve pancreatic islet cell functions as a therapeutic approach to treat T2D.

  7. The Role of Costimulation Blockade in Solid Organ and Islet Xenotransplantation

    Directory of Open Access Journals (Sweden)

    Kannan P. Samy

    2017-01-01

    Full Text Available Pig-to-human xenotransplantation offers a potential bridge to the growing disparity between patients with end-stage organ failure and graft availability. Early studies attempting to overcome cross-species barriers demonstrated robust humoral immune responses to discordant xenoantigens. Recent advances have led to highly efficient and targeted genomic editing, drastically altering the playing field towards rapid production of less immunogenic porcine tissues and even the discussion of human xenotransplantation trials. However, as these humoral immune barriers to cross-species transplantation are overcome with advanced transgenics, cellular immunity to these novel xenografts remains an outstanding issue. Therefore, understanding and optimizing immunomodulation will be paramount for successful clinical xenotransplantation. Costimulation blockade agents have been introduced in xenotransplantation research in 2000 with anti-CD154mAb. Most recently, prolonged survival has been achieved in solid organ (kidney xenograft survival > 400 days with anti-CD154mAb, heart xenograft survival > 900 days, and liver xenograft survival 29 days with anti-CD40mAb and islet xenotransplantation (>600 days with anti-CD154mAb with the use of these potent experimental agents. As the development of novel genetic modifications and costimulation blocking agents converges, we review their impact thus far on preclinical xenotransplantation and the potential for future application.

  8. Transplant Ethics.

    Science.gov (United States)

    Altınörs, Nur; Haberal, Mehmet

    2016-11-01

    The aim of this study was to review and discuss the great variety of ethical issues related to organ donation, organ procurement, transplant activities, and new ethical problems created as a result of technologic and scientific developments. An extensive literature survey was made, and expert opinions were obtained. The gap between demand and supply of organs for transplant has yielded to organ trafficking, organ tourism, and commercialism. This problem seems to be the most important issue, and naturally there are ethical dilemmas related to it. A wide number of ideas have been expressed on the subject, and different solutions have been proposed. The struggle against organ trafficking and commercialism should include legislation, efforts to increase deceased-donor donations, and international cooperation. China's policy to procure organs from prisoners sentenced to death is unethical, and the international community should exert more pressure on the Chinese government to cease this practice. Each particular ethical dilemma should be taken separately and managed.

  9. Distinct cell clusters touching islet cells induce islet cell replication in association with over-expression of Regenerating Gene (REG protein in fulminant type 1 diabetes.

    Directory of Open Access Journals (Sweden)

    Kaoru Aida

    Full Text Available BACKGROUND: Pancreatic islet endocrine cell-supporting architectures, including islet encapsulating basement membranes (BMs, extracellular matrix (ECM, and possible cell clusters, are unclear. PROCEDURES: The architectures around islet cell clusters, including BMs, ECM, and pancreatic acinar-like cell clusters, were studied in the non-diabetic state and in the inflamed milieu of fulminant type 1 diabetes in humans. RESULT: Immunohistochemical and electron microscopy analyses demonstrated that human islet cell clusters and acinar-like cell clusters adhere directly to each other with desmosomal structures and coated-pit-like structures between the two cell clusters. The two cell-clusters are encapsulated by a continuous capsule composed of common BMs/ECM. The acinar-like cell clusters have vesicles containing regenerating (REG Iα protein. The vesicles containing REG Iα protein are directly secreted to islet cells. In the inflamed milieu of fulminant type 1 diabetes, the acinar-like cell clusters over-expressed REG Iα protein. Islet endocrine cells, including beta-cells and non-beta cells, which were packed with the acinar-like cell clusters, show self-replication with a markedly increased number of Ki67-positive cells. CONCLUSION: The acinar-like cell clusters touching islet endocrine cells are distinct, because the cell clusters are packed with pancreatic islet clusters and surrounded by common BMs/ECM. Furthermore, the acinar-like cell clusters express REG Iα protein and secrete directly to neighboring islet endocrine cells in the non-diabetic state, and the cell clusters over-express REG Iα in the inflamed milieu of fulminant type 1 diabetes with marked self-replication of islet cells.

  10. Pancreas Transplantation From Pediatric Donors: A United Network for Organ Sharing Registry Analysis.

    Science.gov (United States)

    Spaggiari, Mario; Bissing, Martha; Campara, Maya; Yeh, Chun-Chieh; Tzvetanov, Ivo; Jeon, Hoonbae; Benedetti, Enrico

    2017-10-01

    Pancreas grafts from pediatric donors are still considered "not ideal." Perceived concerns are related to low islet mass and potential for graft thrombosis. The study evaluated all pancreas transplants from January 2000 to May 2015 using the Organ Procurement and Transplant Network database. Comparative analysis of recipient and graft survival was performed between pediatric (≤18 years) and adult donors. In the pediatric group, the outcomes were stratified based on donor age (≤6, 7-12, and 13-18 years) and weight (95 kg). In the selected era, 18 430 pancreas transplants were performed from 4915 pediatric donors (27%). Short-term graft and patient survivals were comparable between pediatric and adult donors. Ten-year patient and graft survivals were higher in the pediatric donor group: (70% and 54% vs 68% and 51%, P = 0.001). However, very-low-weight pediatric donors (donor pancreas transplants had comparable patient and graft survival to the adult donor transplants. However, the islet mass of very small donors could influence long-term graft survival if the weights of donors and recipients are not properly matched. Usage of "very small" pediatric donors was not associated with higher incidence of technical complications or early graft loss.

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

    DEFF Research Database (Denmark)

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

    1986-01-01

    Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets. These e......Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets....... These effects were dose-dependent and reproducible when using three different Interleukin-1 preparations. Highly purified human Interleukin-2, Lymphotoxin, Leucocyte Migration Inhibitory Factor and Macrophage Migration Inhibitory Factor were ineffective. These findings suggest that Interleukin-1 may play...

  12. 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.

  13. Stem Cell Transplant

    Science.gov (United States)

    ... Graft-versus-host disease: A potential risk when stem cells come from donors If you receive a transplant ... medications and blood products into your body. Collecting stem cells for transplant If a transplant using your own ...

  14. 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...

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

    DEFF Research Database (Denmark)

    Knudsen, P; Kofod, Hans; Lernmark, A

    1983-01-01

    , a cloned rat islet tumor cell line. A twofold increase in islet glutamate dehydrogenase activity was induced by 5 mmol/liter L-leucine OMe, a larger effect than that of L-leucine (P less than 0.02), whereas L-arginine OMe had a small inhibitory effect. We conclude that L-leucine OMe is a potent stimulus...... of insulin secretion and that its effect on the beta-cells may be exerted by activating islet glutamate dehydrogenase....

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

    International Nuclear Information System (INIS)

    Xia, Bing; Zhan, Xiao-Rong; Yi, Ran; Yang, Baofeng

    2009-01-01

    The regenerative process of the pancreas is of interest because the main pathogenesis of diabetes mellitus is an inadequate number of insulin-producing β-cells. The functional mass of β-cells is decreased in type 1 diabetes, so replacing missing β-cells or triggering their regeneration may allow for improved type 1 diabetes treatment. Therefore, expansion of the β-cell mass from endogenous sources, either in vivo or in vitro, represents an area of increasing interest. The mechanism of islet regeneration remains poorly understood, but the identification of islet progenitor sources is critical for understanding β-cell regeneration. One potential source is the islet proper, via the dedifferentiation, proliferation, and redifferentiation of facultative progenitors residing within the islet. Neogenesis, or that the new pancreatic islets can derive from progenitor cells present within the ducts has been reported, but the existence and identity of the progenitor cells have been debated. In this review, we focus on pancreatic ductal cells, which are islet progenitors capable of differentiating into islet β-cells. Islet neogenesis, seen as budding of hormone-positive cells from the ductal epithelium, is considered to be one mechanism for normal islet growth after birth and in regeneration, and has suggested the presence of pancreatic stem cells. Numerous results support the neogenesis hypothesis, the evidence for the hypothesis in the adult comes primarily from morphological studies that have in common the production of damage to all or part of the pancreas, with consequent inflammation and repair. Although numerous studies support a ductal origin for new islets after birth, lineage-tracing experiments are considered the 'gold standard' of proof. Lineage-tracing experiments show that pancreatic duct cells act as progenitors, giving rise to new islets after birth and after injury. The identification of differentiated pancreatic ductal cells as an in vivo progenitor for

  17. 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

  18. Metabolic aspects of neonatal rat islet hypoxia tolerance.

    Science.gov (United States)

    Hyder, Ayman; Laue, Christiane; Schrezenmeir, Jürgen

    2010-01-01

    Sensitivity of pancreatic islets to hypoxia is one of the most important of the obstacles responsible for their failure to survive within the recipients. The aim of this study was to compare the in vitro hypoxia tolerance of neonatal and adult rat islet cells and to study the glucose metabolism in these cells after exposure to hypoxia. Islet cells from both age categories were cultured in different hypoxic levels for 24 h and insulin secretion and some metabolites of glucose metabolism were analysed. Glucose-stimulated insulin secretion decreased dramatically in both cell preparations in response to the decrease in oxygen level. The reduction of insulin secretion was more detectable in adult cells and started at 5% O(2), while a significant reduction was obtained at 1% O(2) in neonatal cells. Moreover, basal insulin release of neonatal cells showed an adaptation to hypoxia after a 4-day culture in hypoxia. Intracellular pyruvate was higher in neonatal cells than in adult ones, while no difference in lactate level was observed between them. Similar results to that of pyruvate were observed for adenosine triphosphate (ATP) and the second messenger cyclic adenosine monophosphate (cAMP). The study reveals that neonatal rat islet cells are more hypoxia-tolerant than the adult ones. The most obvious metabolic observation was that both pyruvate and lactate were actively produced in neonatal cells, while adult cells depended mainly on lactate production as an end-product of glycolysis, indicating a more enhanced metabolic flexibility of neonatal cells to utilize the available oxygen and, at the same time, maintain metabolism anaerobically.

  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. Glucose activates prenyltransferases in pancreatic islet β-cells

    International Nuclear Information System (INIS)

    Goalstone, Marc; Kamath, Vasudeva; Kowluru, Anjaneyulu

    2010-01-01

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

  1. 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....

  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. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

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

    Science.gov (United States)

    Peschke, Elmar; Bähr, Ina; Mühlbauer, Eckhard

    2013-01-01

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

  4. Lattice of optical islets: a novel treatment modality in photomedicine

    International Nuclear Information System (INIS)

    Altshuler, Gregory; Smirnov, Mikhail; Yaroslavsky, Ilya

    2005-01-01

    A majority of photothermal applications of laser and non-laser light sources in medicine (in particular, in dermatology) are based on the paradigm of (extended) selective photothermolysis. However, realization of this principle in its strict form may not always be possible and/or practical. Spatial (or geometric) selectivity (as opposed to wavelength and temporal selectivity) can provide an alternative approach delivering effective and safe treatment techniques. A method of creating a lattice of localized areas of light-tissue interaction (optical islets) is an example of this 'spatially confined' approach. The lattice of optical islets can be formed using a variety of energy sources and delivery optics, including application of lenslet arrays, phase masks and matrices of exogenous chromophores. Using a state-of-the-art theory of optical and thermal light-tissue interactions and a comprehensive computer model of skin, we have conducted a theoretical and numerical analysis of the process of formation of such a lattice in human tissue. Effects of the wavelength, beam geometry, pulsewidth and physical properties of tissues have been considered. Conditions for obtaining optical, thermal and damage islet lattices in the human skin without inducing adverse side effects (e.g. bulk damage) have been established

  5. Comparison of Neutral Proteases and Collagenase Class I as Essential Enzymes for Human Islet Isolation.

    Science.gov (United States)

    Brandhorst, Heide; Kurfürst, Manfred; Johnson, Paul R; Korsgren, Olle; Brandhorst, Daniel

    2016-01-01

    Efficient islet isolation requires synergistic interaction between collagenase class I (CI) and class II (CII). The CI degradation alters the ratio between CI and CII and is responsible for batch-to-batch variations. This study compares the role of neutral protease (NP) plus clostripain (CP) with CI as essential enzymes for human islet isolation. Human islets were isolated using 4 different enzyme mixtures composed of CII plus either intact (CI-115) or degraded CI (CI-100). Blends were administered either with or without NP/CP. Purified islets were cultured for 3 to 4 days before islet quality assessment. Whereas using intact CI-115 without NP/CP did not significantly reduce islet yield (3429 ± 631 vs 3087 ± 970 islet equivalent/g, nonsignificant), administration of degraded CI-100 without NP/CP decreased islet yield from 3501 ± 580 to 1312 ± 244 islet equivalent/g (P P P NP/CP was omitted (P NP/CP was not added. This study suggests that NP/CP can compensate reduced CI activity. Future attempts to optimize enzyme blends should consider the possibility to increase the proportion of collagenase CI to reduce the need for potentially harmful NPs.

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

    Directory of Open Access Journals (Sweden)

    Shen-shen ZHI

    2011-02-01

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

  7. Transplante uterino

    OpenAIRE

    Carvalho, Margarida Teixeira Farias Meira de, 1992-

    2016-01-01

    Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2016 A infertilidade de causa uterina afecta cerca de 3-5% da população geral, sendo a adopção e a gestação de substituição as únicas opções para estes casais atingirem a parentalidade, dado que é um problema ainda sem tratamento. Nas últimas décadas, foram realizados diversos estudos animais com o objectivo de demonstrar a viabilidade, segurança e eficácia do transplante uterino como ...

  8. The safety and availability of xenotransplantated encapsulized newborn porcine islets into the diabetic dog's liver via hepatic artery

    International Nuclear Information System (INIS)

    Ye Bin; Wang Wei; Liu Sheng

    2006-01-01

    Objective: To evaluate the biocompatibility, immunology and physiologic features of encapsulated Newborn Porcine Islets (NPI) in the liver of the recipient dogs with type I diabetes. Methods: Type I diabetic dogs were perfused with 400000-600000 encapsulated NPI (group A, n=15) or unencapsulated NPI (group B, n=15) through the hepatic artery without immunosuppressive treatment. Liver function and CD4/CD8 in the recipients were measured before and after the transplantation. The livers from all NPI recipient dogs were analyzed by histopathology 6 months after transplantation(Tx). Results: Insulin dose administrated to group A was reduced gradually within one week after Tx, from 22 u before Tx to 5 u after Tx, exogenous insulin required for group B was decreased from 24 u to 10 u. However, 2 to 3 weeks after Tx, the insulin dose given to group B returned to the original level before Tx. In contrast, the amount of insulin administrated to group A was continually reduced to 8 u. Moreover, CD4 + cells in the blood of group B recipients were higher than that before Tx, whereas no significant alteration of CD4+ cells and CD8+ cells in the blood of group A after Tx. All NPI recipient dogs demonstrated a normal function and structure of the liver after Tx. Conclusion: Microcapsulated NPI has a good biocompatibility in recipients livers providing prolongation of xenograft survival, and correcting the hyperglycemia of diabetic canines. (authors)

  9. Microencapsulated 3-Dimensional Sensor for the Measurement of Oxygen in Single Isolated Pancreatic Islets

    Science.gov (United States)

    Khalil, Gamal; Sweet, Ian R.; Shen, Amy Q.

    2012-01-01

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

  10. 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.

  11. Abnormal Infant Islet Morphology Precedes Insulin Resistance in PCOS-Like Monkeys

    Science.gov (United States)

    Nicol, Lindsey E.; O’Brien, Timothy D.; Dumesic, Daniel A.; Grogan, Tristan; Tarantal, Alice F.; Abbott, David H.

    2014-01-01

    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. PMID:25207967

  12. Aspectos psicológicos de pacientes diabéticos candidatos ao transplante de ilhotas pancreáticas

    OpenAIRE

    Ester Pereira; Cláudia Menegatti; Luciana Percegona; Carlos Alberto Aita; Miguel Carlos Riella

    2007-01-01

    Diabetic patients see the pancreatic islet transplantation (IT) as an idealized form of cure of the disease, and put great expectations in this treatment. Then, it is important to evaluate psychological aspects that could interfere with the comprehension of the procedure being a clinical study with uncertain results, and with patient adherence at all stages of the project. From March/2004 to March/2005, thirteen IT candidates were evaluated and two of them were reevaluated after six months. P...

  13. 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...

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    Porcine neonatal islet-like cell clusters (NICCs) may be an attractive source of insulin-producing tissue for xenotransplantation in type I diabetic patients. We examined the functional and immunohistochemical outcome of the islet grafts in vitro during long-term culture and in vivo after transpl...

  15. Secretin and its C-terminal hexapeptide potentiates insulin release in mouse islets

    DEFF Research Database (Denmark)

    Kofod, Hans; Hansen, B; Lernmark, A

    1986-01-01

    no stimulatory effect on islet glutamate dehydrogenase activity. In fact, S-(23-27), S-(24-27), and S-(25-27) inhibited the islet glutamate dehydrogenase activity, the activation by which amino acids and amino acid derivatives are known to elicit a potentiation of insulin release. Our results suggest that the C...

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

    NARCIS (Netherlands)

    Moes, H; Koiter, TR

    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

  17. Type 1 Diabetes Candidate Genes Linked to Pancreatic Islet Cell Inflammation and Beta-Cell Apoptosis

    DEFF Research Database (Denmark)

    Størling, Joachim; Pociot, Flemming

    2017-01-01

    Type 1 diabetes (T1D) is a chronic immune-mediated disease resulting from the selective destruction of the insulin-producing pancreatic islet β-cells. Susceptibility to the disease is the result of complex interactions between environmental and genetic risk factors. Genome-wide association studie...... with focus on pancreatic islet cell inflammation and β-cell apoptosis....

  18. A VERSATILE ALGINATE DROPLET GENERATOR APPLICABLE FOR MICROENCAPSULATION OF PANCREATIC-ISLETS

    NARCIS (Netherlands)

    WOLTERS, GHJ; FRITSCHY, WM; GERRITS, D; VANSCHILFAGAARDE, R

    1992-01-01

    Alginate beads for immunoisolation of pancreatic islets by microencapsulation should be small, smooth, and spherical in order to ensure that around the islets a strong alginate-polylysine-alginate capsule will be formed with optimal biocompatibility and diffusion of nutrients and hormones. However,

  19. Immunohistochemical and morphometric study of the development of fetal and newborn rat pancreatic islets

    International Nuclear Information System (INIS)

    Badawoud, Mohammed H.

    2003-01-01

    Aim of this study is to perform a detailed morphometric immunohistochemichal study of develpment of fetal and newborn rat pancreatic islets. 24 pancreas were obtained from 19 and 21-day-old fetal rats,1 and 4-day-old newborn rats. They were fixed in a buffered neutral formalin ,dehydrated and embedded in paraplast. Sections were stained with anti-insulin antibodies. Study was performed at Department of Anatomy, King Abdul-Aziz University, Jeddah,Kingdom of Saudi Arabia, between 2001 and 2002. The volume density of B cells showed a grdual increase during the last days of gestation and a slight increase during the first 4 days after birth. All the other morphometric parameters showed a gradual increase during the last days of gestation and during the first days after birth.The B cell nuclear diameter and volume showed a slight increase after birth. B cells were stained and present in the central part of of fetal and new born islets,while the other islet cells were present in the periphery of the islets. The size of endocrine tissue, which was represented by the islet diameter, islet volume, islet volume density, total number of islet cells,number of B cells and volume density of B cells showed a progressive increase during the prenatal period. (author)

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    Insulin secretion from pancreatic beta-cells is pulsatile with a period of 5-10 min and is believed to be responsible for plasma insulin oscillations with similar frequency. To observe an overall oscillatory insulin pro. le it is necessary that the insulin secretion from individual beta......-cells is synchronized within islets, and that the population of islets is also synchronized. We have recently developed a model in which pulsatile insulin secretion is produced as a result of calcium-driven electrical oscillations in combination with oscillations in glycolysis. We use this model to investigate possible...... mechanisms for intra-islet and inter-islet synchronization. We show that electrical coupling is sufficient to synchronize both electrical bursting activity and metabolic oscillations. We also demonstrate that islets can synchronize by mutually entraining each other by their effects on a simple model "liver...

  1. Incretin and islet hormonal responses to fat and protein ingestion in healthy men

    DEFF Research Database (Denmark)

    Carr, Richard D; Larsen, Marianne O; Winzell, Maria Sörhede

    2008-01-01

    integrated incretin and islet hormone responses to ingestion of pure fat (oleic acid; 0.88 g/kg) or protein (milk and egg protein; 2 g/kg) over 5 h in healthy men, aged 20-25 yr (n=12); plain water ingestion served as control. Both intact (active) and total GLP-1 and GIP levels were determined as was plasma......Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) regulate islet function after carbohydrate ingestion. Whether incretin hormones are of importance for islet function after ingestion of noncarbohydrate macronutrients is not known. This study therefore examined......, the early GIP, but not GLP-1, responses correlated to insulin (r(2)=0.86; P=0.0001) but not glucagon responses. In contrast, after fat ingestion, GLP-1 and GIP did not correlate to islet hormones. We conclude that, whereas protein and fat release both incretin and islet hormones, the early GIP secretion...

  2. Spontaneous Hypoglycemia After Islet Autotransplantation for Chronic Pancreatitis.

    Science.gov (United States)

    Lin, Yu Kuei; Faiman, Charles; Johnston, Philip C; Walsh, R Matthew; Stevens, Tyler; Bottino, Rita; Hatipoglu, Betul A

    2016-10-01

    Spontaneous hypoglycemia has been reported in patients after total pancreatectomy (TP) and islet autotransplantation (IAT) with maintained insulin independence. Details surrounding these events have not been well described. The objective of the study was to determine the frequency and characteristics of spontaneous hypoglycemia in patients undergoing TP-IAT and/or to ascertain predictive or protective factors of its development. This was an observational cohort study in 40 patients who underwent TP-IAT from August 2008 to May 2014, with a median follow-up of 34 months. The study was conducted at a single institution (Cleveland Clinic). Patients included recipients of TP-IAT. The intervention included small, frequent meals in those patients who developed spontaneous hypoglycemia. Incidence of spontaneous hypoglycemia development, characteristics of the patients developing hypoglycemia, and their response to small, frequent meals were measured. Six of 12 patients, who maintained insulin independence, developed spontaneous hypoglycemia. The episodes could be fasting, postprandial, and/or exercise associated, with the frequency ranging from two to three times daily to once every 1-2 weeks. All patients experienced at least one episode that required external assistance, glucagon administration, and/or emergent medical attention. Patients who developed hypoglycemia had a lower median age and tended to have a lower median islet equivalent/kg body weight but a higher median total islet equivalent, body mass index, and homeostatic model assessment for insulin resistance score. All patients who received small, frequent meal intervention had improvement in severity and/or frequency of the hypoglycemic episodes. Spontaneous hypoglycemia is prevalent after TP-IAT. Although the underlying pathophysiology responsible for these hypoglycemia events remains to be elucidated, small, frequent meal intervention is helpful in ameliorating this condition.

  3. Mitis group streptococci express variable pilus islet 2 pili.

    Directory of Open Access Journals (Sweden)

    Dorothea Zähner

    Full Text Available Streptococcus oralis, Streptococcus mitis, and Streptococcus sanguinis are members of the Mitis group of streptococci and agents of oral biofilm, dental plaque and infective endocarditis, disease processes that involve bacteria-bacteria and bacteria-host interactions. Their close relative, the human pathogen S. pneumoniae uses pilus-islet 2 (PI-2-encoded pili to facilitate adhesion to eukaryotic cells.PI-2 pilus-encoding genetic islets were identified in S. oralis, S. mitis, and S. sanguinis, but were absent from other isolates of these species. The PI-2 islets resembled the genetic organization of the PI-2 islet of S. pneumoniae, but differed in the genes encoding the structural pilus proteins PitA and PitB. Two and three variants of pitA (a pseudogene in S. pneumoniae and pitB, respectively, were identified that showed ≈20% difference in nucleotide as well as corresponding protein sequence. Species-independent combinations of pitA and pitB variants indicated prior intra- and interspecies horizontal gene transfer events. Polyclonal antisera developed against PitA and PitB of S. oralis type strain ATCC35037 revealed that PI-2 pili in oral streptococci were composed of PitA and PitB. Electronmicrographs showed pilus structures radiating >700 nm from the bacterial surface in the wild type strain, but not in an isogenic PI-2 deletion mutant. Anti-PitB-antiserum only reacted with pili containing the same PitB variant, whereas anti-PitA antiserum was cross-reactive with the other PitA variant. Electronic multilocus sequence analysis revealed that all PI-2-encoding oral streptococci were closely-related and cluster with non-PI-2-encoding S. oralis strains.This is the first identification of PI-2 pili in Mitis group oral streptococci. The findings provide a striking example of intra- and interspecies horizontal gene transfer. The PI-2 pilus diversity provides a possible key to link strain-specific bacterial interactions and/or tissue tropisms with

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

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram

    2006-01-01

    description of these processes and their interactions would provide important input in the search for a better treatment of the disease. The thesis describes several aspects of mathematical modeling of beta-cells relevant for the understanding of glucose stimulated insulin secretion. It consists...... and the synchronized behavior of many coupled beta-cells as well as to the synchrony of islets. Rather than developing new biophysical models, the thesis investigates existing models, their integration and simplifications, and analyzed the corresponding dynamics, in order to use these models for investigating...

  5. The tick (Acari: Ixodidae) fauna of Herald's Beacon Islet, Australia.

    Science.gov (United States)

    Kwak, Mackenzie L; Mintram, Kate

    2017-01-01

    A rare opportunity to travel to Herald's Beacon Islet with permission from the Australian government to collect ticks allowed for a survey of the tick fauna of the island to be undertaken for the first time. The avian fauna of the island, which serve as hosts, was also recorded and includes one new species record for the island. The seabird soft tick Ornithodoros capensis Neumann and the seabird hard tick Amblyomma loculosum Neumann were found to be present on the island. Images of the ticks present on the island are presented along with morphological characters for their identification.

  6. Pancreatic Islet Cell Amyloidosis Manifesting as a Large Pancreas

    International Nuclear Information System (INIS)

    Onur, Mehmet Ruhi; Yalniz, Mehmet; Poyraz, Ahmet Kursad; Oezercan, Ibrahim Hanifi; Ozkan, Yusuf

    2012-01-01

    A 39-year-old female patient presented to our hospital with epigastric pain lasting for two months. Laboratory results showed impaired glucose tolerance. Ultrasonography of the patient showed a hypoechoic, diffusely enlarged pancreas. CT revealed a large pancreas, with multiple calcifications. On MRI, a diffusely enlarged pancreas was seen hypointense on both T1- and T2-weighted images with heterogeneous enhancement after gadolinium administration. A biopsy of the pancreas revealed primary amyloidosis of islet cells. Decreased signal on T1-weighted images without inflammation findings on CT and MRI were clues for the diagnosis.

  7. Assessment of DNA synthesis in Islet-1{sup +} cells in the adult murine heart

    Energy Technology Data Exchange (ETDEWEB)

    Weinberger, Florian, E-mail: f.weinberger@uke.de; Mehrkens, Dennis, E-mail: dennis.mehrkens@uk-koeln.de; Starbatty, Jutta, E-mail: starbatty@uke.uni-hamburg.de; Nicol, Philipp, E-mail: Philipp.Nicol@gmx.de; Eschenhagen, Thomas, E-mail: t.eschenhagen@uke.de

    2015-01-02

    Highlights: • Islet-1 was expressed in the adult heart. • Islet-1-positive cells did not proliferate in the adult heart. • Sinoatrial node cells did not proliferate in the adult heart. - Abstract: Rationale: Islet-1 positive (Islet-1{sup +}) cardiac progenitor cells give rise to the right ventricle, atria and outflow tract during murine cardiac development. In the adult heart Islet-1 expression is limited to parasympathetic neurons, few cardiomyocytes, smooth muscle cells, within the proximal aorta and pulmonary artery and sinoatrial node cells. Its role in these cells is unknown. Here we tested the hypothesis that Islet-1{sup +} cells retain proliferative activity and may therefore play a role in regenerating specialized regions in the heart. Methods and results: DNA synthesis was analyzed by the incorporation of tritiated thymidine ({sup 3}H-thymidine) in Isl-1-nLacZ mice, a transgenic model with an insertion of a nuclear beta-galactosidase in the Islet-1 locus. Mice received daily injections of {sup 3}H-thymidine for 5 days. DNA synthesis was visualized throughout the heart by dipping autoradiography of cryosections. Colocalization of an nLacZ-signal and silver grains would indicate DNA synthesis in Islet-1{sup +} cells. Whereas Islet{sup −} non-myocyte nuclei were regularly marked by accumulation of silver grains, colocalization with nLacZ-signals was not detected in >25,000 cells analyzed. Conclusions: Islet-1{sup +} cells are quiescent in the adult heart, suggesting that, under normal conditions, even pacemaking cells do not proliferate at higher rates than normal cardiac myocytes.

  8. Assessment of DNA synthesis in Islet-1+ cells in the adult murine heart

    International Nuclear Information System (INIS)

    Weinberger, Florian; Mehrkens, Dennis; Starbatty, Jutta; Nicol, Philipp; Eschenhagen, Thomas

    2015-01-01

    Highlights: • Islet-1 was expressed in the adult heart. • Islet-1-positive cells did not proliferate in the adult heart. • Sinoatrial node cells did not proliferate in the adult heart. - Abstract: Rationale: Islet-1 positive (Islet-1 + ) cardiac progenitor cells give rise to the right ventricle, atria and outflow tract during murine cardiac development. In the adult heart Islet-1 expression is limited to parasympathetic neurons, few cardiomyocytes, smooth muscle cells, within the proximal aorta and pulmonary artery and sinoatrial node cells. Its role in these cells is unknown. Here we tested the hypothesis that Islet-1 + cells retain proliferative activity and may therefore play a role in regenerating specialized regions in the heart. Methods and results: DNA synthesis was analyzed by the incorporation of tritiated thymidine ( 3 H-thymidine) in Isl-1-nLacZ mice, a transgenic model with an insertion of a nuclear beta-galactosidase in the Islet-1 locus. Mice received daily injections of 3 H-thymidine for 5 days. DNA synthesis was visualized throughout the heart by dipping autoradiography of cryosections. Colocalization of an nLacZ-signal and silver grains would indicate DNA synthesis in Islet-1 + cells. Whereas Islet − non-myocyte nuclei were regularly marked by accumulation of silver grains, colocalization with nLacZ-signals was not detected in >25,000 cells analyzed. Conclusions: Islet-1 + cells are quiescent in the adult heart, suggesting that, under normal conditions, even pacemaking cells do not proliferate at higher rates than normal cardiac myocytes

  9. Organ transplantation in Tunisia.

    Science.gov (United States)

    El Matri, Aziz; Ben Abdallah, Taieb

    2015-04-01

    Kidney transplants were first performed in Tunisia in 1986, and transplants soon extended to other organs including the heart, liver, and pancreas. Live-related donor and deceased-donor kidney transplants were both began in the summer of 1986. An organ procurement and transplant law was passed in March 1991, and the National Centre for Advancement of Organ Transplantation was created in 1995. The number of transplantation units has increased to 7 throughout the country, and the yearly transplant number has progressively increased to 139 in 2010, including 20% from deceased kidney donors. Despite these gains, the need continues to grow. Heart transplants began in January 1993, and Tunisia and Jordan are currently the only Arab countries where it is practiced. However, only 16 patients have received a heart transplant as of 2004, and the number of recipients has decreased in the past 10 years. Liver transplants are rare in other Arab countries, but began in Tunisia in January 1998. Over 10 years, 38 patients benefited from this procedure. After a few years of stagnation, the number of liver transplants is increasing. While all types of transplantation are needed, kidney transplantation is a priority in Tunisia. The target is to perform 400 transplants annually, which would require a long-term strategy to provide full financial coverage using the National Health Insurance Funds in both the public and private sectors.

  10. Multimodal Imaging Reveals Improvement of Blood Supply to an Artificial Cell Transplant Site Induced by Bioluminescent Mesenchymal Stem Cells.

    Science.gov (United States)

    Gálisová, Andrea; Fábryová, Eva; Jirák, Daniel; Sticová, Eva; Lodererová, Alena; Herynek, Vít; Kříž, Jan; Hájek, Milan

    2017-02-01

    An artificial site for cell or pancreatic islet transplantation can be created using a polymeric scaffold, even though it suffers subcutaneously from improper vascularisation. A sufficient blood supply is crucial for graft survival and function and can be enhanced by transplantation of mesenchymal stem cells (MSCs). The purpose of this study was to assess the effect of syngeneic MSCs on neoangiogenesis and cell engraftment in an artificial site by multimodal imaging. MSCs expressing a gene for luciferase were injected into the artificial subcutaneous site 7 days after scaffold implantation. MRI experiments (anatomical and dynamic contrast-enhanced images) were performed on a 4.7-T scanner using gradient echo sequences. Bioluminescent images were acquired on an IVIS Lumina optical imager. Longitudinal examination was performed for 2 months, and one animal was monitored for 16 months. We confirmed the long-term presence (lasting more than 16 months) of viable donor cells inside the scaffolds using bioluminescence imaging with an optical signal peak appearing on day 3 after MSC implantation. When compared to controls, the tissue perfusion and vessel permeability in the scaffolds were significantly improved at the site with MSCs with a maximal peak on day 9 after MSC transplantation. Our data suggest that the maximal signal obtained by bioluminescence and magnetic resonance imaging from an artificially created site between 3 and 9 days after MSC transplantation can predict the optimal time range for subsequent cellular or tissue transplantation, including pancreatic islets.

  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. What's hot, what's new in basic science: report from the American Transplant Congress 2015.

    Science.gov (United States)

    Heeger, P S

    2015-11-01

    Research reports presented at the American Transplant Congress 2015 provided an array of basic science findings of relevance to the transplant community. Among key themes is the concept that ischemia-reperfusion injury and early posttransplantation inflammation is linked to adaptive alloimmunity and transplant injury. Molecular and cellular mechanisms contributing to these interactions were highlighted. The relevance of understanding how blocking costimulation, including CD40/CD154 interactions, affects various aspects of the alloimmune response was enhanced by the description of preclinical studies demonstrating efficacy of a unique, blocking anti-CD40 monoclonal antibody that could potentially be used in humans. The identification of mechanisms underlying interactions among T cell subsets and B cells, including follicular helper T cells, regulatory T cells, effector B cells, and regulatory B cells, provides multiple previously unrecognized targets for future therapeutic interventions. Additional reports of interest include novel insights into effects of the gut microbiome on graft survival and the ability to differentiate insulin-secreting, islet-like cells from induced pluripotent stem cells. Overall, the reported basic science findings from American Transplant Congress 2015 add to the fundamental understanding of innate and adaptive alloimmunity and provide novel and testable hypotheses that have the potential to be translated into improved clinical care of transplant patients. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  13. Transplante de intestino delgado Small intestine transplantation

    Directory of Open Access Journals (Sweden)

    Flávio Henrique Ferreira Galvão

    2003-06-01

    Full Text Available RACIONAL: Avanços da biotecnologia e o desenvolvimento de novas drogas imunossupressoras melhoraram os resultados do transplante de intestino delgado. Esse transplante é atualmente indicado para casos especiais da falência intestinal. OBJETIVO: A presente revisão realça os recentes desenvolvimentos na área do transplante de intestino delgado. MATERIAL E MÉTODO: Mais de 600 publicações de transplante de intestino delgado foram revisadas. O desenvolvimento da pesquisa, novas estratégias de imunossupressão, monitorização do enxerto e do receptor, e avanços na técnica cirúrgica são discutidos. RESULTADOS: Realizaram-se cerca de 700 transplante de intestino delgado em 55 centros: 44% intestino-fígado, 41% enxerto intestinal isolado e 15% transplante multivisceral. Rejeição e infecção são as principais limitações desse transplante. Sobrevida de 5 anos na experiência internacional é de 46% para o transplante de intestino isolado, 43% para o intestino-fígado e de cerca de 30% para o transplante multivisceral. Sobrevidas prolongadas são mais freqüentes nos centros com maior experiência. Em série de 165 transplantes intestinais na Universidade de Pittsburgh, PA, EUA, foi relatada sobrevida do paciente maior do que 75% no primeiro ano, 54% em 5 anos e 42% em 10 anos. Mais de 90% desses pacientes assumem dieta oral irrestrita. CONCLUSÃO: O transplante de intestino delgado evoluiu de estratégia experimental para uma alternativa viável no tratamento da falência intestinal permanente. Promover o refinamento da terapia imunossupressora, do manejo e prevenção de infecções, da técnica cirúrgica e da indicação e seleção adequada dos pacientes é crucial para melhorar a sobrevida desse transplante.BACKGROUND: Significant progress has been made in clinical small bowel transplantation over the last decade mainly due advances in biotechnology and new immunosuppressive regiments. This transplantation has now been indicated

  14. Effects of woodland islets introduced in a Mediterranean agricultural landscape on local bird communities

    Directory of Open Access Journals (Sweden)

    I. Razola

    2009-06-01

    Full Text Available This study assesses whether the afforestation approach consisting in the introduction of woodland islets in “agricultural seas” can reconcile the restoration of woody vegetation and the persistence of open-habitat bird populations, providing further opportunities for other forest species to enrich bird diversity at the landscape level. We compared the species richness and abundance of bird communities in a field with 16 introduced woodland islets and in a nearby abandoned field located in central Spain during spring and winter time. The woodland islets presented higher accumulated species richness as well as a higher probability of finding new species if sampling effort were increased only in winter time. These trends were the opposite during spring time. Mean species richness and mean bird abundance were lower at the woodland islets than at the abandoned field in both seasons. We found a higher abundance of open-habitat specialist species in the abandoned field. Woodland islets favoured the wintering of chiffchaff Phylloscopus collybita. We did not find any effects on the only forest specialist species (blue tit Parus caeruleus in spring. Bird richness and abundance were higher in edge islets than in inner islets. The introduction of larger and mixed plantations connected by hedgerows and a management that favoured the development of big trees, a lower tree density and a diverse shrub layer could promote bird diversity, allowing forest specialists and open-habitat species to coexist at the landscape scale.

  15. New class of oxygen carriers improves islet isolation from long-term stored rat pancreata.

    Science.gov (United States)

    Brandhorst, H; Muehling, B; Yamaya, H; Henriksnaes, J; Carlsson, P O; Korsgren, O; Brandhorst, D

    2008-03-01

    Pancreas shipment is frequently associated with prolonged ischemia deteriorating islet graft function. The strategy to prevent ischemic damage utilizing perfluorodecalin (PFD) for human pancreas oxygenation does not seem to improve isolation outcome. The present study investigated the efficiency of perfluorohexyloctane (F6H8), a hyperoxygen carrier characterized by low specific density (1.33 g/cm3) and lipophilic qualities, to facilitate islet isolation from long-term stored rat pancreata. Prior to islet isolation, pancreata were intraductally flushed in situ with Kyoto solution (KS) and stored for 24 hours in KS, oxygenated PFD, or F6H8. Islet isolation performed after 24-hour storage in KS failed completely. The intrapancreatic pO2 in PFD- and F6H8-incubated pancreata was almost the same. In correspondence, the ATP content and viability of isolated islets were similar as well. In contrast, islet yield and in vitro function were significantly reduced after storage in PFD compared with F6H8. This study suggested that islet isolation performed after long-term pancreas preservation can be significantly improved utilizing semifluorinated alkanes as oxygen carriers.

  16. Pancreatic islet blood flow during euglycaemic, hyperinsulinaemic clamp in anaesthetized rats.

    Science.gov (United States)

    Jansson, L; Andersson, A; Bodin, B; Källskog, O

    2007-04-01

    Previous studies have demonstrated that pancreatic islet blood flow is crucially dependent on blood glucose concentration. Thus, hyperglycaemia increases and hypoglycaemia decreases islet blood perfusion, by a combination of nervous and metabolic signals. The aim of the present study was to evaluate if hyperinsulinaemia, without associated hypoglycaemia, affects islet blood flow. Thiobutabarbital-anaesthetized Wistar-Furth rats were subjected to an euglycaemic, hyperinsulinaemic clamp, that is they were infused for 60 min with either saline, insulin (18 mU kg(-1) min(-1)), glucose (27 mg kg(-1) min(-1)) or both glucose and insulin. This was followed by islet blood flow measurements with a microsphere technique. Animals receiving only glucose doubled their blood glucose and serum insulin concentrations, whereas rats receiving only insulin had blood glucose concentrations <2 mmol L(-1) and a 10-fold increase in serum insulin concentrations. Animals given simultaneous glucose and insulin had normal blood glucose concentrations but a 10-fold increase in serum insulin concentrations. Total pancreatic blood flow was unaffected in all animals. Islet blood flow was increased in hyperglycaemic and decreased in hypoglycaemic rats compared with control rats. Islet blood flow did not differ between clamped and control rats. Serum insulin concentration per se does not affect islet blood flow, whereas the ambient blood glucose concentration is of major importance in this context.

  17. Predictors of slow progression to diabetes in children with multiple islet autoantibodies.

    Science.gov (United States)

    Steck, Andrea K; Dong, Fran; Waugh, Kathleen; Frohnert, Brigitte I; Yu, Liping; Norris, Jill M; Rewers, Marian J

    2016-08-01

    Although most children with multiple islet autoantibodies develop type 1 diabetes, rate of progression is highly variable. The goal of this study was to explore potential factors involved in rate of progression to diabetes in children with multiple islet autoantibodies. The Diabetes Autoimmunity Study in the Young (DAISY) has followed 118 children with multiple islet autoantibodies for progression to diabetes. After excluding 27 children currently diabetes-free but followed for 10 years. Islet autoimmunity appeared at 4.0 ± 3.5, 3.2 ± 1.8 and 5.8 ± 3.1 years of age in rapid, moderate and slow progressors, respectively (p = 0.006). Insulin autoantibody levels were lower in slow progressors compared to moderate and rapid progressors. The groups did not differ by gender, ethnicity, family history, susceptibility HLA and non-HLA genes. The rate of development of individual islet autoantibodies including mIAA, GADA, IA-2A and ZnT8A were all slower in the slow versus moderate/rapid progressors. In multivariate analyses, older age at seroconversion and lower initial mIAA levels independently predicted slower progression to diabetes. Later onset of islet autoimmunity and lower autoantibody levels predicted slower progression to diabetes among children with multiple islet autoantibodies. These factors may need to be considered in the design of trials to prevent type 1 diabetes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Causes of limited survival of microencapsulated pancreatic islet grafts

    NARCIS (Netherlands)

    de Groot, Martijn; Schuurs, T.A; van Schilfgaarde, Reinout

    Successful transplantation of pancreatic tissue has been demonstrated to be an efficacious method of restoring glycemic control in type 1 diabetic patients. To establish graft acceptance patients require lifelong immunosuppression, which in turn is associated with severe deleterious side effects.

  19. 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.

  20. Fluorescent protein vectors for pancreatic islet cell identification in live-cell imaging.

    Science.gov (United States)

    Shuai, Hongyan; Xu, Yunjian; Yu, Qian; Gylfe, Erik; Tengholm, Anders

    2016-10-01

    The islets of Langerhans contain different types of endocrine cells, which are crucial for glucose homeostasis. β- and α-cells that release insulin and glucagon, respectively, are most abundant, whereas somatostatin-producing δ-cells and particularly pancreatic polypeptide-releasing PP-cells are more scarce. Studies of islet cell function are hampered by difficulties to identify the different cell types, especially in live-cell imaging experiments when immunostaining is unsuitable. The aim of the present study was to create a set of vectors for fluorescent protein expression with cell-type-specific promoters and evaluate their applicability in functional islet imaging. We constructed six adenoviral vectors for expression of red and green fluorescent proteins controlled by the insulin, preproglucagon, somatostatin, or pancreatic polypeptide promoters. After transduction of mouse and human islets or dispersed islet cells, a majority of the fluorescent cells also immunostained for the appropriate hormone. Recordings of the sub-plasma membrane Ca(2+) and cAMP concentrations with a fluorescent indicator and a protein biosensor, respectively, showed that labeled cells respond to glucose and other modulators of secretion and revealed a striking variability in Ca(2+) signaling among α-cells. The measurements allowed comparison of the phase relationship of Ca(2+) oscillations between different types of cells within intact islets. We conclude that the fluorescent protein vectors allow easy identification of specific islet cell types and can be used in live-cell imaging together with organic dyes and genetically encoded biosensors. This approach will facilitate studies of normal islet physiology and help to clarify molecular defects and disturbed cell interactions in diabetic islets.

  1. [Promoting Living Kidney Transplantation].

    Science.gov (United States)

    Lin, Chiu-Chu

    2016-04-01

    Kidney transplantation is the best approach for treating patients with end stage renal disease, offering patients the best chance of returning to normal health. While the techniques used in kidney transplantation surgery are mature and highly successful, there is a severe shortage of donor organs. Statistics show a serious imbalance between organ donations and patients on the waiting list for organ transplantation. Moreover, evidence from empirical studies has shown a better transplantation outcome for patients who receive living donor transplantation than for those who receive organs from cadavers. Although using relatives as donors offers an effective way to reduce the problem of organ shortage, this strategy faces many challenges and many other factors affect the promotion of living donor transplantation. This article elaborates how cultural and psychological factors, kidney transplantation awareness, and ethics and laws impact upon living kidney donations and then proposes coping strategies for promoting living kidney transplantation.

  2. BONE MARROW TRANSPLANTATION

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. BONE MARROW TRANSPLANTATION. AUTOLOGOUS TRANSPLANTS: Oct 1986 - Dec 2007. Multiple Myeloma 90. NHL 39. Hodgkins lymphoma 19. AML 36. APML 9. ALL 2. Amyloidosis 2. Granulocytic Sarcoma 1.

  3. Life After Transplant

    Science.gov (United States)

    ... however you can Daughter's dying wish became mother's motivation Be The Match Blog Stories Anna, transplant recipient ... Jobs Job application FAQs E-Verify Career events Employee benefits About us Bea, transplant recipient Be The ...

  4. Choosing a Transplant Center

    Science.gov (United States)

    ... however you can Daughter's dying wish became mother's motivation Be The Match Blog Stories Anna, transplant recipient ... Jobs Job application FAQs E-Verify Career events Employee benefits About us Bea, transplant recipient Be The ...

  5. Treatment Before Transplant

    Science.gov (United States)

    ... however you can Daughter's dying wish became mother's motivation Be The Match Blog Stories Anna, transplant recipient ... Jobs Job application FAQs E-Verify Career events Employee benefits About us Bea, transplant recipient Be The ...

  6. Cord Blood and Transplants

    Science.gov (United States)

    ... however you can Daughter's dying wish became mother's motivation Be The Match Blog Stories Anna, transplant recipient ... Jobs Job application FAQs E-Verify Career events Employee benefits About us Bea, transplant recipient Be The ...

  7. A systems genetics approach identifies genes and pathways for type 2 diabetes in human islets

    DEFF Research Database (Denmark)

    Taneera, Jalal; Lang, Stefan; Sharma, Amitabh

    2012-01-01

    gene coexpression and protein-protein interaction networks that were strongly associated with islet insulin secretion and HbA(1c). We integrated our data to form a rank list of putative T2D genes, of which CHL1, LRFN2, RASGRP1, and PPM1K were validated in INS-1 cells to influence insulin secretion......, whereas GPR120 affected apoptosis in islets. Expression variation of the top 20 genes explained 24% of the variance in HbA(1c) with no claim of the direction. The data present a global map of genes associated with islet dysfunction and demonstrate the value of systems genetics for the identification...

  8. 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

    and recombinant IL-1 derived from the predominant pI 7 form of human IL-1, consistently inhibited the insulin response. The pI 6 and pI 5 forms of natural IL-1 were ineffective. Natural and recombinant IL-1 exhibited similar dose responses in their islet-inhibitory effect and their thymocyte-stimulatory activity....... Concentrations of IL-1 that inhibited islet activity were in the picomolar range. Hence, monocyte-derived pI 7 IL-1 may contribute to islet cell damage and therefore to the development of insulin-dependent diabetes mellitus....

  9. Blood and Bone MarrowTransplant?

    Science.gov (United States)

    ... Topics / Blood and Bone Marrow Transplant Blood and Bone Marrow Transplant Also known as Hematopoietic Stem Cell Transplant , Hematopoietic Cell Transplant , Autologous Transplant , Allogeneic Transplant A blood or bone marrow ...

  10. Organ Transplants in Kazakhstan.

    Science.gov (United States)

    Baigenzhin, Abay; Doskaliyev, Zhaksylyk; Tuganbekova, Saltanat; Zharikov, Serik; Altynova, Sholpan; Gaipov, Abduzhappar

    2015-11-01

    The Republic of Kazakhstan is one of the fastest developing countries in the world and has a health care system that is unique in Central Asia. Its organ transplant services are also developing rapidly. We aimed to analyze and briefly report on the current status of organ transplant in the Republic of Kazakhstan. We analyzed organ transplant activities in that country for the period 2012 to 2014. All data were collected from the official database of the National Transplant Coordinating Center of the Republic of Kazakhstan. At the end of 2014, the number of transplant centers had increased to 10, three of which could perform multiorgan transplants; during the same period, the number of deceased-donor organ-donating hospitals increased up to 37. By 2013, the transplant activity rate for all centers had reached 9.22 per million population. During the previous 3 years (2012-2014), there was a 3-fold increase in the number of living donors and an 18-fold increase in the number of kidney transplants. Between 2012 and 2014, the number of living-donor liver transplants increased from 17 to 25, and the number of deceased-donor transplants increased from 3 to 7. During the last 3 years (2012-2014), the number of heart transplants increased to 7 cases. During the last 3 years (2012-2014), Kazakhstan achieved a significant improvement in the organization of its transplant services, and a noticeable upward trend in the system continues.

  11. 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

  12. The hypothalamic satiety peptide CART is expressed in anorectic and non-anorectic pancreatic islet tumors and in the normal islet of Langerhans.

    Science.gov (United States)

    Jensen, P B; Kristensen, P; Clausen, J T; Judge, M E; Hastrup, S; Thim, L; Wulff, B S; Foged, C; Jensen, J; Holst, J J; Madsen, O D

    1999-03-26

    The hypothalamic satiety peptide CART (cocaine and amphetamine regulated transcript) is expressed at high levels in anorectic rat glucagonomas but not in hypoglycemic insulinomas. However, a non-anorectic metastasis derived from the glucagonoma retained high CART expression levels and produced circulating CART levels comparable to that of the anorectic tumors. Moreover, distinct glucagonoma lines derived by stable HES-1 transfection of the insulinoma caused severe anorexia but retained low circulating levels of CART comparable to that of insulinoma bearing or control rats. Islet tumor associated anorexia and circulating CART levels are thus not correlated, and in line with this peripheral administration of CART (5-50 mg/kg) produced no effect on feeding behavior. In the rat two alternatively spliced forms of CART mRNA exist and quantitative PCR revealed expression of both forms in the hypothalamus, in the different islet tumors, and in the islets of Langerhans. Immunocytochemistry as well as in situ hybridization localized CART expression to the somatostatin producing islet D cell. A potential endocrine/paracrine role of islet CART remains to be clarified.

  13. Donor exosomes rather than passenger leukocytes initiate alloreactive T cell responses after transplantation

    Science.gov (United States)

    Marino, Jose; Babiker-Mohamed, Mohamed H.; Crosby-Bertorini, Patrick; Paster, Joshua T.; LeGuern, Christian; Germana, Sharon; Abdi, Reza; Uehara, Mayuko; Kim, James I.; Markmann, James F.; Tocco, Georges; Benichou, Gilles

    2016-01-01

    Transplantation of allogeneic organs and tissues represents a lifesaving procedure for a variety of patients affected with end-stage diseases. Although current immunosuppressive therapy prevents early acute rejection, it is associated with nephrotoxicity and increased risks for infection and neoplasia. This stresses the need for selective immune-based therapies relying on manipulation of lymphocyte recognition of donor antigens. The passenger leukocyte theory states that allograft rejection is initiated by recipient T cells recognizing donor major histocompatibility complex (MHC) molecules displayed on graft leukocytes migrating to the host’s lymphoid organs. We revisited this concept in mice transplanted with allogeneic skin, heart, or islet grafts using imaging flow cytometry. We observed no donor cells in the lymph nodes and spleen of skin-grafted mice, but we found high numbers of recipient cells displaying allogeneic MHC molecules (cross-dressed) acquired from donor microvesicles (exosomes). After heart or islet transplantation, we observed few donor leukocytes (100 per million) but large numbers of recipient cells cross-dressed with donor MHC (>90,000 per million). Last, we showed that purified allogeneic exosomes induced proinflammatory alloimmune responses by T cells in vitro and in vivo. Collectively, these results suggest that recipient antigen-presenting cells cross-dressed with donor MHC rather than passenger leukocytes trigger T cell responses after allotransplantation. PMID:27942611

  14. An 'alpha-beta' of pancreatic islet microribonucleotides

    DEFF Research Database (Denmark)

    Dalgaard, Louise Torp; Eliasson, Lena

    2017-01-01

    . Moreover, processing of miRNAs appears to be altered by obesity, diabetes, and aging. A number of miRNAs (such as miR-7, miR-21, miR-29, miR-34a, miR-212/miR-132, miR-184, miR-200 and miR-375) are involved in mediating beta cell dysfunction and/or compensation induced by hyperglycemia, oxidative stress......, cytotoxic cytokines, and in rodent models of fetal metabolic programming prediabetes and overt diabetes. Studies of human type 2 diabetic islets underline that these miRNA families could have important roles also in human type 2 diabetes. Furthermore, there is a genuine gap of knowledge regarding mi...

  15. Computational Modelling of the Human Islet Amyloid Polypeptide

    DEFF Research Database (Denmark)

    Skeby, Katrine Kirkeby

    2014-01-01

    of a specific protein into amyloid fibrils. During this process, a cytotoxic event occurs which can be a serious actor in the evolvement of the disease. This thesis is concerned with elucidating the biological processes concerning amyloid proteins, more specifically, the peptide hormone human islet amyloid...... setup. We have exploited these strengths to study the interactions between an amyloid fibril and amyloid imaging agents. Imaging agents are promising tools for the detection of amyloid deposits in the brain of AD patients. This could aid in the early diagnosis as well as evaluation of new treatments......When proteins do not fold correctly, it can lead to very serious diseases. One such group of diseases is the amyloid diseases, of which Alzheimer’s disease (AD), Parkinson’s disease, and type 2 diabetes mellitus (T2DM) are members. The amyloid diseases are characterized by the aggregation...

  16. CT anglographic evaluation of pancreatic islet cell tumors

    International Nuclear Information System (INIS)

    Merine, D.S.; Fishman, E.K.; Kuhlman, J.E.; Siegelman, S.S.; Widlus, D.M.; Cameron, J.L.

    1989-01-01

    To increase the accuracy of CT staging of pancreatic cancer, the authors modified the standard techniques for CT angiography (CTA). Six patients with known or suspected pancreatic islet cell tumors were examined by CTA. The catheter was placed in the superior mesenteric artery, and a sequence of dynamic CT scans were obtained while 150 mL of Hypaque-30 was injected at a rate of 2 mL/sec. In addition to clear identification of the pancreatic tumor mass, CTA proved valuable in evaluating liver metastasis (n = 3) and venous thrombosis (n = 2. In one case, a 1-cm functioning insulinoma was demonstrated by CTA after unsuccessful angiographic detection. In all cases, correlation with surgical or biopsy results showed the CTA to be accurate

  17. Pediatric Liver Transplantation.

    Science.gov (United States)

    Rawal, Nidhi; Yazigi, Nada

    2017-06-01

    Excellent outcomes over the last 3 decades have made liver transplantation the treatment of choice for many advanced liver disorders. This success also opened liver transplantation to new indications such as liver tumors and metabolic disorders. The emergence of such new indications for liver transplantation is bringing a new stream of patients along with disease-specific challenges. The cumulative number of liver transplant recipients is peaking, requiring novel systems of health care delivery that meet the needs of this special patient population. This article reviews updates and new development in pediatric liver transplantation. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Total pancreatectomy and islet autotransplantation: A decade nationwide analysis.

    Science.gov (United States)

    Fazlalizadeh, Reza; Moghadamyeghaneh, Zhobin; Demirjian, Aram N; Imagawa, David K; Foster, Clarence E; Lakey, Jonathan R; Stamos, Michael J; Ichii, Hirohito

    2016-03-24

    To investigate outcomes and predictors of in-hospital morbidity and mortality after total pancreatectomy (TP) and islet autotransplantation. The nationwide inpatient sample (NIS) database was used to identify patients who underwent TP and islet autotransplantation (IAT) between 2002-2012 in the United States. Variables of interest were inherent variables of NIS database which included demographic data (age, sex, and race), comorbidities (such as diabetes mellitus, hypertension, and deficiency anemia), and admission type (elective vs non-elective). The primary endpoints were mortality and postoperative complications according to the ICD-9 diagnosis codes which were reported as the second to 25(th) diagnosis of patients in the database. Risk adjusted analysis was performed to investigate morbidity predictors. Multivariate regression analysis was used to identify predictors of in-hospital morbidity. We evaluated a total of 923 patients who underwent IAT after pancreatectomy during 2002-2012. Among them, there were 754 patients who had TP + IAT. The most common indication of surgery was chronic pancreatitis (86%) followed by acute pancreatitis (12%). The number of patients undergoing TP + IAT annually significantly increased during the 11 years of study from 53 cases in 2002 to 155 cases in 2012. Overall mortality and morbidity of patients were 0% and 57.8 %, respectively. Post-surgical hypoinsulinemia was reported in 42.3% of patients, indicating that 57.7% of patients were insulin independent during hospitalization. Predictors of in-hospital morbidity were obesity [adjusted odds ratio (AOR): 3.02, P = 0.01], fluid and electrolyte disorders (AOR: 2.71, P < 0.01), alcohol abuse (AOR: 2.63, P < 0.01), and weight loss (AOR: 2.43, P < 0.01). TP + IAT is a safe procedure with no mortality, acceptable morbidity, and achieved high rate of early insulin independence. Obesity is the most significant predictor of in-hospital morbidity.

  19. Differential expression of glutamic acid decarboxylase in rat and human islets

    DEFF Research Database (Denmark)

    Petersen, J S; Russel, S; Marshall, M O

    1993-01-01

    islets, whereas only GAD64 mRNA was detected in human islets. Immunocytochemical analysis of rat and human pancreatic sections or isolated islets with antibodies to GAD64 and GAD67 in combination with antibodies to insulin, glucagon, or SRIF confirmed that a GAD64 and GAD67 expression were beta......The GABA synthesizing enzyme GAD is a prominent islet cell autoantigen in type I diabetes. The two forms of GAD (GAD64 and GAD67) are encoded by different genes in both rats and humans. By in situ hybridization analysis of rat and human pancreases, expression of both genes was detected in rat...... as observed in vivo, whereas GAD67 was localized not only to the beta-cells but also in the alpha-cells and delta-cells. A small but distinct fraction of GAD positive cells in these monolayer cultures did not accumulate GABA immunoreactivity, which may indicate cellular heterogeneity with respect to GABA...

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

    Directory of Open Access Journals (Sweden)

    Shao-Yu Peng

    2017-06-01

    Conclusion: Altogether, islet-like cells have the potential to be differentiated from CPSCs without gene manipulation, and can be used in diabetic animal models in the future for preclinical and drug testing trial investigations.

  1. Human Fibroblast Sheet Promotes Human Pancreatic Islet Survival and Function In Vitro.

    Science.gov (United States)

    Matsushima, Hajime; Kuroki, Tamotsu; Adachi, Tomohiko; Kitasato, Amane; Ono, Shinichiro; Tanaka, Takayuki; Hirabaru, Masataka; Kuroshima, Naoki; Hirayama, Takanori; Sakai, Yusuke; Soyama, Akihiko; Hidaka, Masaaki; Takatsuki, Mitsuhisa; Kin, Tatsuya; Shapiro, James; Eguchi, Susumu

    2016-01-01

    In previous work, we engineered functional cell sheets using bone marrow-derived mesenchymal stem cells (BM-MSCs) to promote islet graft survival. In the present study, we hypothesized that a cell sheet using dermal fibroblasts could be an alternative to MSCs, and then we aimed to evaluate the effects of this cell sheet on the functional viability of human islets. Fibroblast sheets were fabricated using temperature-responsive culture dishes. Human islets were seeded onto fibroblast sheets. The efficacy of the fibroblast sheets was evaluated by dividing islets into three groups: the islets-alone group, the coculture with fibroblasts group, and the islet culture on fibroblast sheet group. The ultrastructure of the islets cultured on each fibroblast sheet was examined by electron microscopy. The fibroblast sheet expression of fibronectin (as a component of the extracellular matrix) was quantified by Western blotting. After 3 days of culture, islet viabilities were 70.2 ± 9.8%, 87.4 ± 5.8%, and 88.6 ± 4.5%, and survival rates were 60.3 ± 6.8%, 65.3 ± 3.0%, and 75.8 ± 5.6%, respectively. Insulin secretions in response to high-glucose stimulation were 5.1 ± 1.6, 9.4 ± 3.8, and 23.5 ± 12.4 µIU/islet, and interleukin-6 (IL-6) secretions were 3.0 ± 0.7, 5.1 ± 1.2, and 7.3 ± 1.0 ng/day, respectively. Islets were found to incorporate into the fibroblast sheets while maintaining a three-dimensional structure and well-preserved extracellular matrix. The fibroblast sheets exhibited a higher expression of fibronectin compared to fibroblasts alone. In conclusion, human dermal fibroblast sheets fabricated by tissue-engineering techniques could provide an optimal substrate for human islets, as a source of cytokines and extracellular matrix.

  2. Endovascular method for transplantation of insulin-producing cells to the pancreas parenchyma in swine.

    Science.gov (United States)

    Lundberg, J; Stone-Elander, S; Zhang, X-M; Korsgren, O; Jonsson, S; Holmin, S

    2014-03-01

    Insulin-producing cells are transplanted by portal vein injection as an alternative to pancreas transplantation in both clinical and preclinical trials. Two of the main limitations of portal vein transplantation are the prompt activation of the innate immunity and concomitant loss of islets and a small but significant risk of portal vein thrombosis. Furthermore, to mimic physiological release, the insulin-producing cells should instead be located in the pancreas. The trans-vessel wall approach is an endovascular method for penetrating the vessel wall from the inside. In essence, a working channel is established to the parenchyma of organs that are difficult to access by percutaneous technique. In this experiment, we accessed the extra-vascular pancreatic parenchyma in swine by microendovascular technique and injected methylene blue, contrast fluids and insulin-producing cells without acute adverse events. Further, we evaluated the procedure itself by a 1-year angiographical follow-up, without adverse events. This study shows that the novel approach utilizing endovascular minimal invasiveness coupled to accurate trans-vessel wall placement of an injection in the pancreatic parenchyma with insulin-producing cells is possible. In clinical practice, the potential benefits compared to portal vein cell transplantation should significantly improve endocrine function of the graft and potentially reduce adverse events. © 2014 The Authors. American Journal of Transplantation Published by Wiley Periodicals, Inc. on behalf of American Society of Transplant Surgeons.

  3. Status and distribution of breeding seabirds in the northern islets of Lanzarote, Canary Islands

    OpenAIRE

    Rodríguez, Beneharo; León, Leandro de; Martín, Aurelio; Alonso, Jesús; Nogales, Manuel

    2003-01-01

    We describe the results of a survey of breeding seabirds carried out between 2000 and 2002 in the northern islets of Lanzarote, Canary Islands, with particular emphasis on their status and distribution. For White-faced Stormpetrel Pelagodroma marina, Madeiran Storm-petrel Oceanodroma castro, Lesser Blackhacked Gull Larus [fuscus] graellsii and Yellow-legged Gull Larus cachinnans atlantis, somenew colonies were discovered on different islets. All species have maintained their numbers over the ...

  4. Genetic disassociation of autoimmunity and resistance to costimulation blockade-induced transplantation tolerance in nonobese diabetic mice.

    Science.gov (United States)

    Pearson, Todd; Markees, Thomas G; Serreze, David V; Pierce, Melissa A; Marron, Michele P; Wicker, Linda S; Peterson, Laurence B; Shultz, Leonard D; Mordes, John P; Rossini, Aldo A; Greiner, Dale L

    2003-07-01

    Curing type 1 diabetes by islet transplantation requires overcoming both allorejection and recurrent autoimmunity. This has been achieved with systemic immunosuppression, but tolerance induction would be preferable. Most islet allotransplant tolerance induction protocols have been tested in nonobese diabetic (NOD) mice, and most have failed. Failure has been attributed to the underlying autoimmunity, assuming that autoimmunity and resistance to transplantation tolerance have a common basis. Out of concern that NOD biology could be misleading in this regard, we tested the hypothesis that autoimmunity and resistance to transplantation tolerance in NOD mice are distinct phenotypes. Unexpectedly, we observed that (NOD x C57BL/6)F(1) mice, which have no diabetes, nonetheless resist prolongation of skin allografts by costimulation blockade. Further analyses revealed that the F(1) mice shared the dendritic cell maturation defects and abnormal CD4(+) T cell responses of the NOD but had lost its defects in macrophage maturation and NK cell activity. We conclude that resistance to allograft tolerance induction in the NOD mouse is not a direct consequence of overt autoimmunity and that autoimmunity and resistance to costimulation blockade-induced transplantation tolerance phenotypes in NOD mice can be dissociated genetically. The outcomes of tolerance induction protocols tested in NOD mice may not accurately predict outcomes in human subjects.

  5. The fractal spatial distribution of pancreatic islets in three dimensions: a self-avoiding growth model

    International Nuclear Information System (INIS)

    Jo, Junghyo; Periwal, Vipul; Hörnblad, Andreas; Ahlgren, Ulf; Kilimnik, German; Hara, Manami

    2013-01-01

    The islets of Langerhans, responsible for controlling blood glucose levels, are dispersed within the pancreas. A universal power law governing the fractal spatial distribution of islets in two-dimensional pancreatic sections has been reported. However, the fractal geometry in the actual three-dimensional pancreas volume, and the developmental process that gives rise to such a self-similar structure, has not been investigated. Here, we examined the three-dimensional spatial distribution of islets in intact mouse pancreata using optical projection tomography and found a power law with a fractal dimension of 2.1. Furthermore, based on two-dimensional pancreatic sections of human autopsies, we found that the distribution of human islets also follows a universal power law with a fractal dimension of 1.5 in adult pancreata, which agrees with the value previously reported in smaller mammalian pancreas sections. Finally, we developed a self-avoiding growth model for the development of the islet distribution and found that the fractal nature of the spatial islet distribution may be associated with the self-avoidance in the branching process of vascularization in the pancreas. (paper)

  6. Analysis of pancreas tissue in a child positive for islet cell antibodies.

    Science.gov (United States)

    Oikarinen, M; Tauriainen, S; Honkanen, T; Vuori, K; Karhunen, P; Vasama-Nolvi, C; Oikarinen, S; Verbeke, C; Blair, G E; Rantala, I; Ilonen, J; Simell, O; Knip, M; Hyöty, H

    2008-10-01

    Type 1 diabetes is caused by an immune-mediated process, reflected by the appearance of autoantibodies against pancreatic islets in the peripheral circulation. Detection of multiple autoantibodies predicts the development of diabetes, while positivity for a single autoantibody is a poor prognostic marker. The present study assesses whether positivity for a single autoantibody correlates with pathological changes in the pancreas. We studied post mortem pancreatic tissue of a child who repeatedly tested positive for islet cell antibodies (ICA) in serial measurements. Paraffin sections were stained with antibodies specific for insulin, glucagon, somatostatin, interferon alpha, CD3, CD68, cyclooxygenase-2 (COX-2), beta-2-microglobulin, coxsackie B and adenovirus receptor (CAR), natural killer and dendritic cells. Apoptosis was detected using Fas-specific antibody and TUNEL assay. Enterovirus was searched for using immunohistochemistry and in situ hybridisation, as well as enterovirus-specific RT-PCR from serum samples. The structure of the pancreas did not differ from normal. The number of beta cells was not reduced and no signs of insulitis were observed. Beta-2-microglobulin and CAR were strongly produced in the islets, but not in the exocrine pancreas. Enterovirus protein was detected selectively in the islets by two enterovirus-specific antibodies, but viral RNA was not found. These observations suggest that positivity for ICA alone, even when lasting for more than 1 year, is not associated with inflammatory changes in the islets. However, it is most likely that the pancreatic islets were infected by an enterovirus in this child.

  7. 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

  8. Targeting pancreatic islets with phage display assisted by laser pressure catapult microdissection.

    Science.gov (United States)

    Yao, Virginia J; Ozawa, Michael G; Trepel, Martin; Arap, Wadih; McDonald, Donald M; Pasqualini, Renata

    2005-02-01

    Heterogeneity of the microvasculature in different organs has been well documented by multiple methods including in vivo phage display. However, less is known about the diversity of blood vessels within functionally distinct regions of organs. Here, we combined in vivo phage display with laser pressure catapult microdissection to identify peptide ligands for vascular receptors in the islets of Langerhans in the murine pancreas. Protein database analyses of the peptides, CVSNPRWKC and CHVLWSTRC, showed sequence identity to two ephrin A-type ligand homologues, A2 and A4. Confocal microscopy confirmed that most immunoreactivity of CVSNPRWKC and CHVLWSTRC phage was associated with blood vessels in pancreatic islets. Antibodies recognizing EphA4, a receptor for ephrin-A ligands, were similarly associated with islet blood vessels. Importantly, binding of both islet-homing phage and anti-EphA4 antibody was strikingly increased in blood vessels of pancreatic islet tumors in RIP-Tag2 transgenic mice. These results indicate that endothelial cells of blood vessels in pancreatic islets preferentially express EphA4 receptors, and this expression is increased in tumors. Our findings show in vivo phage display and laser pressure catapult microdissection can be combined to reveal endothelial cell specialization within focal regions of the microvasculature.

  9. PAX4 Defines an Expandable β-Cell Subpopulation in the Adult Pancreatic Islet.

    Science.gov (United States)

    Lorenzo, Petra I; Fuente-Martín, Esther; Brun, Thierry; Cobo-Vuilleumier, Nadia; Jimenez-Moreno, Carmen María; G Herrera Gomez, Irene; López Noriega, Livia; Mellado-Gil, José Manuel; Martin-Montalvo, Alejandro; Soria, Bernat; Gauthier, Benoit R

    2015-10-27

    PAX4 is a key regulator of pancreatic islet development whilst in adult acute overexpression protects β-cells against stress-induced apoptosis and stimulates proliferation. Nonetheless, sustained PAX4 expression promotes β-cell dedifferentiation and hyperglycemia, mimicking β-cell failure in diabetic patients. Herein, we study mechanisms that allow stringent PAX4 regulation endowing favorable β-cell adaptation in response to changing environment without loss of identity. To this end, PAX4 expression was monitored using a mouse bearing the enhanced green fluorescent protein (GFP) and cre recombinase construct under the control of the islet specific pax4 promoter. GFP was detected in 30% of islet cells predominantly composed of PAX4-enriched β-cells that responded to glucose-induced insulin secretion. Lineage tracing demonstrated that all islet cells were derived from PAX4(+) progenitor cells but that GFP expression was confined to a subpopulation at birth which declined with age correlating with reduced replication. However, this GFP(+) subpopulation expanded during pregnancy, a state of active β-cell replication. Accordingly, enhanced proliferation was exclusively detected in GFP(+) cells consistent with cell cycle genes being stimulated in PAX4-overexpressing islets. Under stress conditions, GFP(+) cells were more resistant to apoptosis than their GFP(-) counterparts. Our data suggest PAX4 defines an expandable β-cell sub population within adult islets.

  10. Conditional islet hypovascularisation does not preclude beta cell expansion during pregnancy in mice.

    Science.gov (United States)

    Staels, Willem; Heremans, Yves; Leuckx, Gunter; Van Gassen, Naomi; Salinno, Ciro; De Groef, Sofie; Cools, Martine; Keshet, Eli; Dor, Yuval; Heimberg, Harry; De Leu, Nico

    2017-06-01

    Endothelial-endocrine cell interactions and vascular endothelial growth factor (VEGF)-A signalling are deemed essential for maternal islet vascularisation, glucose control and beta cell expansion during mouse pregnancy. The aim of this study was to assess whether pregnancy-associated beta cell expansion was affected under conditions of islet hypovascularisation. Soluble fms-like tyrosine kinase 1 (sFLT1), a VEGF-A decoy receptor, was conditionally overexpressed in maternal mouse beta cells from 1.5 to 14.5 days post coitum. Islet vascularisation, glycaemic control, beta cell proliferation, individual beta cell size and total beta cell volume were assessed in both pregnant mice and non-pregnant littermates. Conditional overexpression of sFLT1 in beta cells resulted in islet hypovascularisation and glucose intolerance in both pregnant and non-pregnant mice. In contrast to non-pregnant littermates, glucose intolerance in pregnant mice was transient. sFLT1 overexpression did not affect pregnancy-associated changes in beta cell proliferation, individual beta cell size or total beta cell volume. Reduced intra-islet VEGF-A signalling results in maternal islet hypovascularisation and impaired glycaemic control but does not preclude beta cell expansion during mouse pregnancy.

  11. Neurotransmitters and Neuropeptides: New Players in the Control of Islet of Langerhans' Cell Mass and Function.

    Science.gov (United States)

    Di Cairano, Eliana S; Moretti, Stefania; Marciani, Paola; Sacchi, Vellea Franca; Castagna, Michela; Davalli, Alberto; Folli, Franco; Perego, Carla

    2016-04-01

    Islets of Langerhans control whole body glucose homeostasis, as they respond, releasing hormones, to changes in nutrient concentrations in the blood stream. The regulation of hormone secretion has been the focus of attention for a long time because it is related to many metabolic disorders, including diabetes mellitus. Endocrine cells of the islet use a sophisticate system of endocrine, paracrine and autocrine signals to synchronize their activities. These signals provide a fast and accurate control not only for hormone release but also for cell differentiation and survival, key aspects in islet physiology and pathology. Among the different categories of paracrine/autocrine signals, this review highlights the role of neurotransmitters and neuropeptides. In a manner similar to neurons, endocrine cells synthesize, accumulate, release neurotransmitters in the islet milieu, and possess receptors able to decode these signals. In this review, we provide a comprehensive description of neurotransmitter/neuropetide signaling pathways present within the islet. Then, we focus on evidence supporting the concept that neurotransmitters/neuropeptides and their receptors are interesting new targets to preserve β-cell function and mass. A greater understanding of how this network of signals works in physiological and pathological conditions would advance our knowledge of islet biology and physiology and uncover potentially new areas of pharmacological intervention. J. Cell. Physiol. 231: 756-767, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  12. Fractal spatial distribution of pancreatic islets in three dimensions: a self-avoiding growth model

    Science.gov (United States)

    Jo, Junghyo; Hörnblad, Andreas; Kilimnik, German; Hara, Manami; Ahlgren, Ulf; Periwal, Vipul

    2013-01-01

    The islets of Langerhans, responsible for controlling blood glucose levels, are dispersed within the pancreas. A universal power law governing the fractal spatial distribution of islets in two-dimensional pancreatic sections has been reported. However, the fractal geometry in the actual three-dimensional pancreas volume, and the developmental process that gives rise to such a self-similar structure, have not been investigated. Here, we examined the three-dimensional spatial distribution of islets in intact mouse pancreata using optical projection tomography and found a power law with a fractal dimension, 2.1. Furthermore, based on two-dimensional pancreatic sections of human autopsies, we found that the distribution of human islets also follows a universal power law with fractal dimension 1.5 in adult pancreata, which agrees with the value previously reported in smaller mammalian pancreas sections. Finally, we developed a self-avoiding growth model for the development of the islet distribution and found that the fractal nature of the spatial islet distribution may be associated with the self-avoidance in the branching process of vascularization in the pancreas. PMID:23629025

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

    Directory of Open Access Journals (Sweden)

    Fang Xia

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

  14. Generation of Transplantable Beta Cells for Patient-Specific Cell Therapy

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2012-01-01

    Full Text Available Islet cell transplantation offers a potential cure for type 1 diabetes, but it is challenged by insufficient donor tissue and side effects of current immunosuppressive drugs. Therefore, alternative sources of insulin-producing cells and isletfriendly immunosuppression are required to increase the efficiency and safety of this procedure. Beta cells can be transdifferentiated from precursors or another heterologous (non-beta-cell source. Recent advances in beta cell regeneration from somatic cells such as fibroblasts could circumvent the usage of immunosuppressive drugs. Therefore, generation of patient-specific beta cells provides the potential of an evolutionary treatment for patients with diabetes.

  15. Classic and current opinion in embryonic organ transplantation.

    Science.gov (United States)

    Hammerman, Marc R

    2014-04-01

    Here, we review the rationale for the use of organs from embryonic donors, antecedent investigations and recent work from our own laboratory, exploring the utility for transplantation of embryonic kidney and pancreas as an organ replacement therapy. Ultrastructurally precise kidneys differentiate in situ in rats following xenotransplantation in mesentery of embryonic pig renal primordia. The developing organ attracts its blood supply from the host. Engraftment of pig renal primordia requires host immune suppression. However, beta cells originating from embryonic pig pancreas obtained very early following initiation of organogenesis [embryonic day 28 (E28)] engraft long term in nonimmune-suppressed diabetic rats or rhesus macaques. Engraftment of morphologically similar cells originating from adult porcine islets of Langerhans occurs in animals previously transplanted with E28 pig pancreatic primordia. Organ primordia engraft, attract a host vasculature and differentiate following transplantation to ectopic sites. Attempts have been made to exploit these characteristics to achieve clinically relevant endpoints for end-stage renal disease and diabetes mellitus using animal models. We and others have focused on use of the embryonic pig as a donor.

  16. MRI of pancreatic transplants

    International Nuclear Information System (INIS)

    Studniarek, M.; Deschamps, P.Y.; Finas, B.; Pinet, A.

    1993-01-01

    The value of MRI in assessing pancreatic transplants was studied in 37 patients. Sixty-seven MRI examinations were performed in patients with an uncomplicated transplant, 14 in patients with poorly functioning transplant, and 10 in patients with a non-functioning graft. On the basis of 54 follow-up studies, it was shown that the volume of the graft decreased systematically during the 8 months after transplantation. On T1-weighted images the normal transplant was poorly delineated, with an almost homogeneous isointense or slightly hyperintense structure when compared with either renal transplant cortex or muscle. On T2-weighted images the organ was isointense or slightly hypointense compared with fat and hyperintense compared with muscle. T2-weighted delayed echo time image (TR = 2000 ms, TE = 150-200 ms) showed transplanted pancreas as well-delineated, hypointense and with a lobulated structure. This structure was characteristic of normal whole pancreatic grafts. Patent transplant vessels were seen as tubular structures of low signal intensity on T2-weighted short echo time images (TR = 2000 ms, TE = 50 ms). In the 10 patients with a non-functioning pancreatic transplant there were: 4 cases of focal intraparenchymal abnormalities, 6 cases in which the lobular structure was absent, and 4 cases of absence of patent graft main vessels (3 thromboses). There was no configuration of signal intensity of pancreatic parenchyma on MRI which could be considered typical for normal or non-functioning transplant. (orig.)

  17. Rfx6 is an Ngn3-dependent winged helix transcription factor required for pancreatic islet cell development.

    Science.gov (United States)

    Soyer, Josselin; Flasse, Lydie; Raffelsberger, Wolfgang; Beucher, Anthony; Orvain, Christophe; Peers, Bernard; Ravassard, Philippe; Vermot, Julien; Voz, Marianne L; Mellitzer, Georg; Gradwohl, Gérard

    2010-01-01

    The transcription factor neurogenin 3 (Neurog3 or Ngn3) controls islet cell fate specification in multipotent pancreatic progenitor cells in the mouse embryo. However, our knowledge of the genetic programs implemented by Ngn3, which control generic and islet subtype-specific properties, is still fragmentary. Gene expression profiling in isolated Ngn3-positive progenitor cells resulted in the identification of the uncharacterized winged helix transcription factor Rfx6. Rfx6 is initially expressed broadly in the gut endoderm, notably in Pdx1-positive cells in the developing pancreatic buds, and then becomes progressively restricted to the endocrine lineage, suggesting a dual function in both endoderm development and islet cell differentiation. Rfx6 is found in postmitotic islet progenitor cells in the embryo and is maintained in all developing and adult islet cell types. Rfx6 is dependent on Ngn3 and acts upstream of or in parallel with NeuroD, Pax4 and Arx transcription factors during islet cell differentiation. In zebrafish, the Rfx6 ortholog is similarly found in progenitors and hormone expressing cells of the islet lineage. Loss-of-function studies in zebrafish revealed that rfx6 is required for the differentiation of glucagon-, ghrelin- and somatostatin-expressing cells, which, in the absence of rfx6, are blocked at the progenitor stage. By contrast, beta cells, whose number is only slightly reduced, were no longer clustered in a compact islet. These data unveil Rfx6 as a novel regulator of islet cell development.

  18. 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.

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

    Science.gov (United States)

    Vetterli, Laurène; Carobbio, Stefania; Pournourmohammadi, Shirin; Martin-Del-Rio, Rafael; Skytt, Dorte M; Waagepetersen, Helle S; Tamarit-Rodriguez, Jorge; Maechler, Pierre

    2012-10-01

    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 from βGlud1(-/-) mice resulted in abrogation of insulin release evoked by glutamine combined with 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid or l-leucine. Reintroduction of GDH in βGlud1(-/-) islets fully restored the secretory response. Regarding glucose stimulation, insulin secretion in islets isolated from βGlud1(-/-) mice exhibited half of the response measured in control islets. The amplifying pathway, tested at stimulatory glucose concentrations in the presence of KCl and diazoxide, was markedly inhibited in βGlud1(-/-) islets. On glucose stimulation, net synthesis of glutamate from α-ketoglutarate was impaired in GDH-deficient islets. Accordingly, glucose-induced elevation of glutamate levels observed in control islets was absent in βGlud1(-/-) islets. Parallel biochemical pathways, namely alanine and aspartate aminotransferases, could not compensate for the lack of GDH. However, the secretory response to glucose was fully restored by the provision of cellular glutamate when βGlud1(-/-) islets were exposed to dimethyl glutamate. This shows that permissive levels of glutamate are required for the full development of glucose-stimulated insulin secretion and that GDH plays an indispensable role in this process.

  20. The Beta Cell in Its Cluster: Stochastic Graphs of Beta Cell Connectivity in the Islets of Langerhans.

    Directory of Open Access Journals (Sweden)

    Deborah A Striegel

    2015-08-01

    Full Text Available Pancreatic islets of Langerhans consist of endocrine cells, primarily α, β and δ cells, which secrete glucagon, insulin, and somatostatin, respectively, to regulate plasma glucose. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Due to the central functional significance of this local connectivity in the placement of β cells in an islet, it is important to characterize it quantitatively. However, quantification of the seemingly stochastic cytoarchitecture of β cells in an islet requires mathematical methods that can capture topological connectivity in the entire β-cell population in an islet. Graph theory provides such a framework. Using large-scale imaging data for thousands of islets containing hundreds of thousands of cells in human organ donor pancreata, we show that quantitative graph characteristics differ between control and type 2 diabetic islets. Further insight into the processes that shape and maintain this architecture is obtained by formulating a stochastic theory of β-cell rearrangement in whole islets, just as the normal equilibrium distribution of the Ornstein-Uhlenbeck process can be viewed as the result of the interplay between a random walk and a linear restoring force. Requiring that rearrangements maintain the observed quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that β-cell rearrangement is dependent on its connectivity in order to maintain an optimal cluster size in both normal and T2D islets.

  1. Diffusion weighted MR imaging of pancreatic islet cell tumors

    International Nuclear Information System (INIS)

    Bakir, Baris; Salmaslioglu, Artur; Poyanli, Arzu; Rozanes, Izzet; Acunas, Bulent

    2010-01-01

    Purpose: The aim of our study is to demonstrate the feasibility of body diffusion weighted (DW) MR imaging in the evaluation of pancreatic islet cell tumors (ICTs) and to define apparent diffusion coefficient (ADC) values for these tumors. Materials and methods: 12 normal volunteers and 12 patients with histopathologically proven pancreatic ICT by surgery were included in the study. DW MR images were obtained by a body-phased array coil using a multisection single-shot echo planar sequence on the axial plane without breath holding. In addition, the routine abdominal imaging protocol for pancreas was applied in the patient group. We measured the ADC value within the normal pancreas in control group, pancreatic ICT, and surrounding pancreas parenchyma. Mann-Whitney U-test has been used to compare ADC values between tumoral tissues and normal pancreatic tissues of the volunteers. Wilcoxon Signed Ranks Test was preferred to compare ADC values between tumoral tissues and surrounding pancreatic parenchyma of the patients. Results: In 11 patients out of 12, conventional MR sequences were able to demonstrate ICTs successfully. In 1 patient an indistinct suspicious lesion was noted at the pancreatic tail. DW sequence was able to demonstrate the lesions in all of the 12 patients. On the DW images, all ICTs demonstrated high signal intensity relative to the surrounding pancreatic parenchyma. The mean and standard deviations of the ADC values (x10 -3 mm 2 /s) were as follows: ICT (n = 12), 1.51 ± 0.35 (0.91-2.11), surrounding parenchyma (n = 11) 0.76 ± 0.15 (0.51-1.01) and normal pancreas in normal volunteers (n = 12), 0.80 ± 0.06 (0.72-0.90). ADC values of the ICT were significantly higher compared with those of surrounding parenchyma (p < 0.01) and normal pancreas (p < 0.001). Conclusion: DW MR imaging does not appear to provide significant contribution to routine MR imaging protocol in the evaluation of pancreatic islet cell tumors. But it can be added to MR imaging

  2. Diffusion weighted MR imaging of pancreatic islet cell tumors

    Energy Technology Data Exchange (ETDEWEB)

    Bakir, Baris [Department of Radiology, Istanbul University, Istanbul Medical School, Capa 34390, Istanbul (Turkey)], E-mail: drbarisbakir@yahoo.com; Salmaslioglu, Artur; Poyanli, Arzu; Rozanes, Izzet; Acunas, Bulent [Department of Radiology, Istanbul University, Istanbul Medical School, Capa 34390, Istanbul (Turkey)

    2010-04-15

    Purpose: The aim of our study is to demonstrate the feasibility of body diffusion weighted (DW) MR imaging in the evaluation of pancreatic islet cell tumors (ICTs) and to define apparent diffusion coefficient (ADC) values for these tumors. Materials and methods: 12 normal volunteers and 12 patients with histopathologically proven pancreatic ICT by surgery were included in the study. DW MR images were obtained by a body-phased array coil using a multisection single-shot echo planar sequence on the axial plane without breath holding. In addition, the routine abdominal imaging protocol for pancreas was applied in the patient group. We measured the ADC value within the normal pancreas in control group, pancreatic ICT, and surrounding pancreas parenchyma. Mann-Whitney U-test has been used to compare ADC values between tumoral tissues and normal pancreatic tissues of the volunteers. Wilcoxon Signed Ranks Test was preferred to compare ADC values between tumoral tissues and surrounding pancreatic parenchyma of the patients. Results: In 11 patients out of 12, conventional MR sequences were able to demonstrate ICTs successfully. In 1 patient an indistinct suspicious lesion was noted at the pancreatic tail. DW sequence was able to demonstrate the lesions in all of the 12 patients. On the DW images, all ICTs demonstrated high signal intensity relative to the surrounding pancreatic parenchyma. The mean and standard deviations of the ADC values (x10{sup -3} mm{sup 2}/s) were as follows: ICT (n = 12), 1.51 {+-} 0.35 (0.91-2.11), surrounding parenchyma (n = 11) 0.76 {+-} 0.15 (0.51-1.01) and normal pancreas in normal volunteers (n = 12), 0.80 {+-} 0.06 (0.72-0.90). ADC values of the ICT were significantly higher compared with those of surrounding parenchyma (p < 0.01) and normal pancreas (p < 0.001). Conclusion: DW MR imaging does not appear to provide significant contribution to routine MR imaging protocol in the evaluation of pancreatic islet cell tumors. But it can be added to

  3. Thoracic organ transplantation.

    Science.gov (United States)

    Pierson, Richard N; Barr, Mark L; McCullough, Keith P; Egan, Thomas; Garrity, Edward; Jessup, Mariell; Murray, Susan

    2004-01-01

    This article presents an overview of factors associated with thoracic transplantation outcomes over the past decade and provides valuable information regarding the heart, lung, and heart-lung waiting lists and thoracic organ transplant recipients. Waiting list and post-transplant information is used to assess the importance of patient demographics, risk factors, and primary cardiopulmonary disease on outcomes. The time that the typical listed patient has been waiting for a heart, lung, or heart-lung transplant has markedly increased over the past decade, while the number of transplants performed has declined slightly and survival after transplant has plateaued. Waiting list mortality, however, appears to be declining for each organ and for most diseases and high-severity subgroups, perhaps in response to recent changes in organ allocation algorithms. Based on perceived inequity in organ access and in response to a mandate from Health Resources and Services Administration, the lung transplant community is developing a lung allocation system designed to minimize deaths on the waiting list while maximizing the benefit of transplant by incorporating post-transplant survival and quality of life into the algorithm. Areas where improved data collection could inform evolving organ allocation and candidate selection policies are emphasized.

  4. Antidiabetic effects of Eucalyptus globulus on pancreatic islets: a stereological study.

    Science.gov (United States)

    Mahmoudzadeh-Sagheb, H; Heidari, Z; Bokaeian, M; Moudi, B

    2010-05-01

    The leaves of Eucalyptus globulus (eucalyptus) are used for the treatment of diabetes mellitus in traditional medicine. The aim of this study was to evaluate the effects of eucalyptus on streptozotocin (STZ)-induced damage in pancreatic islands by stereological methods. Fifty mature normoglycaemic male Wistar rats, weighing 200-250 g, were selected and randomly divided into 5 groups (n = 10): control; STZ-induced diabetic (D) - by intraperitoneal injection of 60 mg/kg streptozotocin; treated control (TC); and treated diabetic (TD1, 2), respectively, received 20 and 62.5 g/kg of eucalyptus in their diet, and 2.5 g/L aqueous extract of eucalyptus in their drinking water from one week after induction of diabetes. After four weeks of the experiment, stereological estimation of volume density and total volume of islets and beta cells, volume-weighted mean islet volume, mass of the islets and pancreas, and total number of islets were carried out. Administration of eucalyptus significantly decreased the weight loss and increase of water and food intake in the treated diabetic groups in comparison to the STZ-induced diabetic (D) group. Volume density and total volume of islets, volume-weighted mean islet volume, mass of islets, and mass of pancreas of both treated diabetic groups were higher than the D group. In TD2, these stereological parameters increased significantly compared to the D group (p 0.05). The results suggested that Eucalyptus globulus with a dose-dependent manner ameliorates diabetic states by partial restoration of pancreatic beta cells and repair of STZ-induced damage in rats. This study suggests a beneficial effect of eucalyptus in the treatment of diabetes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, Louise T., E-mail: ltd@ruc.dk [Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (United States); Department of Science, Systems and Models, Roskilde University (Denmark)

    2012-01-06

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

  6. Alternative splicing and differential expression of the islet autoantigen IGRP between pancreas and thymus contributes to immunogenicity of pancreatic islets but not diabetogenicity in humans

    NARCIS (Netherlands)

    de Jong, V. Martijn; Abreu, Joana R. F.; Verrijn Stuart, Annemarie A.; van der Slik, Arno R.; Verhaeghen, Katrijn; Engelse, Marten A.; Blom, Bianca; Staal, Frank J. T.; Gorus, Frans K.; Roep, Bart O.

    2013-01-01

    Thymic expression of self-antigens during T-lymphocyte development is believed to be crucial for preventing autoimmunity. It has been suggested that G6PC2, the gene encoding islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), is differentially spliced between pancreatic

  7. Pancreatic islet isolation by mechanical-enzymatic separation, stationary collagenase digestion and dextran discontinuous density gradient purification: experimental study in dogs Isolamento das ilhotas pancreáticas pela separação mecânica-enzimática digestão estacionária com colagenase e purificação com gradiente de densidade descontínua de dextran: estudo experimental em cães

    Directory of Open Access Journals (Sweden)

    Jaques Waisberg

    2002-04-01

    Full Text Available The prospects for allotransplantation of pancreatic islets in man depend on the development of methods that provide sufficient quantities of pancreatic islets from a single donor, which are capable, when transplanted, of achieve the normalization of carbohydrate metabolism. Objective: Evaluate the efficacy of the isolation of Langerhans islets from dogs, by means of mechanical-enzymatic separation technique with stationary digestion using collagenase, and purification with a discontinuous dextran density gradient. Methods: The counting of islet numbers and evaluation of their sizes was accomplished by staining with diphenylthiocarbazone and using stereoscopic microscopes equipped with eyepiece reticule for the measurement of average diameters of stained islets. Results: The results disclosed that the average number of islets isolated was 81032.20 ± 24736.79 and the average number of islets isolated per kg of body weight was 6938.70 ± 1392.43. The average number of islets isolated per kg of body weight showed significant correlation with body weight and weight of the pancreas resected. Conclusion: The number of islets isolated, of a single donor, by mechanical-enzymatic separation, stationary collagenase digestion and discontinuous dextran density gradient purification can be sufficient to success of pancreatic islets transplant in dogs.A perspectiva do alotransplante de ilhotas pancreáticas no homem está na dependência do desenvolvimento de métodos que propiciem quantidades suficientes de ilhotas pancreáticas, originadas de doador único, capazes de, quando transplantadas, levarem à normalização do metabolismo dos hidratos de carbono. Objetivo: Avaliar, em cães, a eficácia do isolamento das ilhotas de Langerhans por meio da técnica de separação mecânica-enzimática, digestão estacionária com colagenase e purificação pelo gradiente de densidade descontínua de dextran. Métodos: A contagem do número e avaliação do tamanho

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

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    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.

  9. Management of Islet Cell Tumours: A Single Hospital Experience.

    Science.gov (United States)

    Fu, Wenguang; Li, Jing; Wen, Jian; Lin, Gao; Wei, Zeng; Deng, Jiaqi; Li, Qiu; Lei, Zhengming

    2015-05-01

    Islet cell tumours (ICTs) are uncommon tumours in clinical practice. Surgical resection is the treatment of choice for ICTs, but localisation of these lesions can be challenging. The aim of this study was to analyse the clinical diagnosis and treatment for ICTs. Thirty-one patients with ICTs who were diagnosed and who underwent surgical treatment in the affiliate hospital of Luzhou Medical College from 1 January 2000 to 31 July 2013 were enrolled. The clinical data of these patients were retrospectively reviewed. Among 31 patients (6 males, 25 females), 15 cases (48.39%) had non-functional ICTs and 16 (51.61%) cases were insulinoma. The mean age of patients with non-functional ICTs was 42.73 ± 12.34 years and of those with insulinoma was 48.88 ± 13 years. Non-functional ICTs had a non-specific presentation. Insulinoma makes different clinical presentations mostly with symptoms of hypoglycaemia. Preoperative and/or intra-operative localisation is needed for ICTs; CT scan or MRI is used routinely as the first choice. If the lesion is very small, DSA is also good for localisation before operation. IOUS is a reliable technique in exactly localising insulinoma. ICTs are considered to be cured with successful surgical removal.

  10. Islet-1 Immunoreactivity in the Developing Retina of Xenopus laevis

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    Guadalupe Álvarez-Hernán

    2013-01-01

    Full Text Available The LIM-homeodomain transcription factor Islet1 (Isl1 has been widely used as a marker of neuronal differentiation in the developing visual system of different classes of vertebrates, including mammals, birds, reptiles, and fish. In the present study, we analyzed the spatial and temporal distribution of Isl1-immunoreactive cells during Xenopus laevis retinal development and its relation to the formation of the retinal layers, and in combination with different markers of cell differentiation. The earliest Isl1 expression appeared at St29-30 in the cell nuclei of sparse differentiating neuroblasts located in the vitreal surface of the undifferentiated retina. At St35-36, abundant Isl1-positive cells accumulated at the vitreal surface of the neuroepithelium. As development proceeded and through the postmetamorphic juveniles, Isl1 expression was identified in subpopulations of ganglion cells and in subsets of amacrine, bipolar, and horizontal cells. These data together suggest a possible role for Isl1 in the early differentiation and maintenance of different retinal cell types, and Isl1 can serve as a specific molecular marker for the study of retinal cell specification in X. laevis.

  11. The hyperbolic effect of density and strength of inter beta-cell coupling on islet bursting: a theoretical investigation

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    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.

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

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    DANIEL A CUNHA

    2006-01-01

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

  13. Kidney transplantation after previous liver transplantation: analysis of the organ procurement transplant network database.

    Science.gov (United States)

    Gonwa, Thomas A; McBride, Maureen A; Mai, Martin L; Wadei, Hani M

    2011-07-15

    Patients after liver transplant have a high incidence of chronic kidney disease and end-stage renal disease (ESRD). We investigated kidney transplantation after liver transplantation using the Organ Procurement Transplant Network database. The Organ Procurement Transplant Network database was queried for patients who received kidney transplantation after previous liver transplantation. These patients were compared with patients who received primary kidney transplantation alone during the same time period. Between 1997 and 2008, 157,086 primary kidney transplants were performed. Of these, 680 deceased donor kidney transplants and 410 living donor kidney transplants were performed in previous recipients of liver transplants. The number of kidney after liver transplants performed each year has increased from 37 per year to 124 per year in 2008. The time from liver transplant to kidney transplant increased from 8.2 to 9.0 years for living donor transplants and from 5.4 to 9.6 years for deceased donor. The 1, 3, and 5 year actuarial graft survival in both living donor kidney after liver transplant and deceased donor kidney after liver transplant are less than the kidney transplant alone patients. However, the death-censored graft survivals are equal. The patient survival is also less but is similar to what would be expected in liver transplant recipients who did not have ESRD. In 2008, kidney after liver transplantation represented 0.9% of the total kidney alone transplants performed in the United States. Kidney transplantation is an appropriate therapy for selected patients who develop ESRD after liver transplantation.

  14. Pancreas transplantation in the treatment of diabetes mellitus type 1: modern aspects

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    S. V. Gautier

    2017-01-01

    Full Text Available Diabetes mellitus is a significant social problem. In the Russian Federation, the prevalence of diabetes type 1 is 340.000 people, 21% of them having diabetic nephropathy, as well as other secondary complications leading to disability and high mortality. There are several options for diabetic patients with chronic kidney disease dialysis: kidney transplantation with insulin therapy, simultaneous kidney-pancreas transplant or islet transplant. Good long-term results could be obtained by the whole pancreas and kidney combined transplantation through maximum metabolism recovery comparing to other replacement therapy options. The recipientselection with special attention to the cardiovascular system evaluation is essential to successful transplantation. The proper pancreatic graft assessment needs a wide range of criteria to be analyzed. Integral scores can simplify and systematize the assessment. The choice of preservation technique is important to pancreatic graft ischemia-reperfusion injury minimization. Despite the progress in graft preservation methods, cold storage using University of Wisconsin (UW solution remains to be the gold standard. The evolution of surgical technique has resulted in utilizing the most physiologic variations of exocrine drainage and venous outflow of the pancreas, so-called portoenteric drainages, which were designed to improve remote metabolic effects and to reduce complications probability.

  15. A personal perspective: 100-year history of the humoral theory of transplantation.

    Science.gov (United States)

    Terasaki, Paul I

    2012-04-27

    The humoral theory states that antibodies cause the rejection of allografts. From 1917 to 1929, extensive efforts were made to produce antibodies against tumors. It was finally realized that the antibodies were produced against the transplant antigens present on transplantable tumors, not against the tumor-specific antigens. To get around this problem, inbred mouse strains were developed, leading to identification of the transplant antigens determined by the H-2 locus of mice. The antibodies were hemagglutinating and cytotoxic antibodies. The analogous human leukocyte antigen system was established by analysis of lymphocytotoxic alloantibodies that were made by pregnant women, directed against mismatched antigens of the fetus. The human leukocyte antigen antibodies were then found to cause hyperacute rejection, acute rejection, and chronic rejection of kidneys. Antibodies appeared in almost all patients after rejection of kidneys. With Luminex single antigen bead technology, donor-specific antibodies could be identified before rise in serum creatinine and graft failure. Antibodies were shown to be predictive of subsequent graft failure in kidney, heart, and lung transplants: patients without antibodies had superior 4-year graft survival compared with those who did have antibodies. New evidence that antibodies are also associated with chronic failure has appeared for liver and islet transplants. Four studies have now shown that removal or reduction of antibodies result in higher graft survival. If removal of antibodies prevents chronic graft failure, final validation of the humoral theory can be achieved.

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

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    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.

  17. Insulin secretion and glucose uptake by isolated islets of the hamster

    International Nuclear Information System (INIS)

    Dunbar, J.C.; McLaughlin, W.J.; Walsh, M.F.J.; Foa, P.P.

    1976-01-01

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

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

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    Fabienne Billiard

    2018-01-01

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

  19. Coxsackievirus-Induced Proteomic Alterations in Primary Human Islets Provide Insights for the Etiology of Diabetes

    Science.gov (United States)

    Nyalwidhe, Julius O.; Gallagher, Glen R.; Glenn, Lindsey M.; Morris, Margaret A.; Vangala, Pranitha; Jurczyk, Agata; Bortell, Rita; Harlan, David M.; Nadler, Jerry L.

    2017-01-01

    Enteroviral infections have been associated with the development of type 1 diabetes (T1D), a chronic inflammatory disease characterized by autoimmune destruction of insulin-producing pancreatic beta cells. Cultured human islets, including the insulin-producing beta cells, can be infected with coxsackievirus B4 (CVB4) and thus are useful for understanding cellular responses to infection. We performed quantitative mass spectrometry analysis on cultured primary human islets infected with CVB4 to identify molecules and pathways altered upon infection. Corresponding uninfected controls were included in the study for comparative protein expression analyses. Proteins were significantly and differentially regulated in human islets challenged with virus compared with their uninfected counterparts. Complementary analyses of gene transcripts in CVB4-infected primary islets over a time course validated the induction of RNA transcripts for many of the proteins that were increased in the proteomics studies. Notably, infection with CVB4 results in a considerable decrease in insulin. Genes/proteins modulated during CVB4 infection also include those involved in activation of immune responses, including type I interferon pathways linked to T1D pathogenesis and with antiviral, cell repair, and inflammatory properties. Our study applies proteomics analyses to cultured human islets challenged with virus and identifies target proteins that could be useful in T1D interventions. PMID:29264452

  20. How stable is repression of disallowed genes in pancreatic islets in response to metabolic stress?

    Science.gov (United States)

    Lemaire, Katleen; Granvik, Mikaela; Schraenen, Anica; Goyvaerts, Lotte; Van Lommel, Leentje; Gómez-Ruiz, Ana; In 't Veld, Peter; Gilon, Patrick; Schuit, Frans

    2017-01-01

    The specific phenotype of mature differentiated beta cells not only depends on the specific presence of genes that allow beta cell function but also on the selective absence of housekeeping genes ("disallowed genes") that would interfere with this function. Recent studies have shown that both histone modifications and DNA methylation via the de novo methyltransferase DNMT3A are involved in repression of disallowed genes in neonatal beta cells when these cells acquire their mature phenotype. It is unknown, however, if the environmental influence of advanced age, pregnancy and the metabolic stress of high fat diet or diabetes could alter the repression of disallowed genes in beta cells. In the present study, we show that islet disallowed genes-which are also deeply repressed in FACS-purified beta cells-remain deeply repressed in animals of advanced age and in pregnant females. Moreover, the stability of this repression was correlated with strong and stable histone repression marks that persisted in islets isolated from 2 year old mice and with overall high expression of Dnmt3a in islets. Furthermore, repression of disallowed genes was unaffected by the metabolic stress of high fat diet. However, repression of about half of the disallowed genes was weakened in 16 week-old diabetic db/db mice. In conclusion, we show that the disallowed status of islet genes is stable under physiological challenging conditions (advanced age, pregnancy, high fat diet) but partially lost in islets from diabetic animals.

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

    International Nuclear Information System (INIS)

    Permutt, M.A.; Koranyi, L.; Keller, K.; Lacy, P.E.; Scharp, D.W.; Mueckler, M.

    1989-01-01

    Previous studies have suggested that pancreatic islet glucose transport is mediated by a high-K m , low-affinity facilitated transporter similar to that expressed in liver. To determine the relationship between islet and liver glucose transporters, liver-type glucose-transporter cDNA clones were isolated from a human liver cDNA library. The liver-type glucose-transporter cDNA clone hybridized to mRNA transcripts of the same size in human liver and pancreatic islet RNA. A cDNA library was prepared from purified human pancreatic islet tissue and screened with human liver-type glucose-transporter cDNA. The authors isolated two overlapping cDNA clones encompassing 2600 base pairs, which encode a pancreatic islet protein identical in sequence to that of the putative liver-type glucose-transporter protein. Xenopus oocytes injected with synthetic mRNA transcribed from a full-length cDNA construct exhibited increased uptake of 2-deoxyglucose, confirming the functional identity of the clone. These cDNA clones can now be used to study regulation of expression of the gene and to assess the role of inherited defects in this gene as a candidate for inherited susceptibility to non-insulin-dependent diabetes mellitus

  2. 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.

  3. Liver transplantation : an update

    NARCIS (Netherlands)

    Verdonk, R. C.; Van den Berg, A. P.; Slooff, M. J. H.; Porte, R. J.; Haagsma, E. B.

    2007-01-01

    Liver transplantation has been an accepted treatment for end-stage liver disease since the 1980s. Currently it is a highly successful treatment for this indication. The aim of this review is to give a general update on recent developments in the field of liver transplantation. In the last decades

  4. Rehabilitation following hand transplantation.

    Science.gov (United States)

    Bueno, Ericka; Benjamin, Marie-Jose; Sisk, Geoffroy; Sampson, Christian E; Carty, Matthew; Pribaz, Julian J; Pomahac, Bohdan; Talbot, Simon G

    2014-03-01

    Hand allotransplantation can restore motor, sensory and cosmetic functions to upper extremity amputees. Over 70 hand transplant operations have been performed worldwide, but there is little published regarding post-hand transplant rehabilitation. The Brigham and Women's Hospital (BWH) Hand Transplantation Team's post-hand transplant rehabilitation protocol is presented here. The protocol must be modified to address each transplant recipient's unique needs. It builds on universally used modalities of hand rehabilitation such as splinting, edema and scar management, range of motion exercises, activities of daily living training, electrical stimulation, cognitive training and strengthening. The BWH hand transplant rehabilitation protocol consists of four phases with distinct goals, frequency, and modalities. (1) Pre-operative: functional assessments are completed and goals and expectations of transplantation are established. (2) Initial post-operative (post-operative weeks 1-2): hand protection, minimization of swelling, education, and discharge. (3) Intermediate (post-operative weeks 2-8): therapy aims to prevent and/or decrease scar adhesion, increase tensile strength, flexibility and function, and prevent joint contractures. (4) Late (from 8 weeks forward): maximization of function and strength, and transition to routine activities. The frequency of rehabilitation therapy decreases gradually from the initial to late phases. Rehabilitation therapy after hand transplantation follows a progressive increase in activity in parallel with wound healing and nerve regeneration. Careful documentation of progress and outcomes is essential to demonstrate the utility of interventions and to optimize therapy protocols.

  5. Customizing Fair Use Transplants

    Directory of Open Access Journals (Sweden)

    Peter K. Yu

    2018-02-01

    Full Text Available In the past decade, policymakers and commentators across the world have called for the introduction of copyright reform based on the fair use model in the United States. Thus far, Israel, Liberia, Malaysia, the Philippines, Singapore, South Korea, Sri Lanka and Taiwan have adopted the fair use regime or its close variants. Other jurisdictions such as Australia, Hong Kong and Ireland have also advanced proposals to facilitate such adoption. This article examines the increasing efforts to transplant fair use into the copyright system based on the U.S. model. It begins by briefly recapturing the strengths and weaknesses of legal transplants. The article then scrutinizes the ongoing effort to transplant fair use from the United States. Specifically, it identifies eight modalities of transplantation. This article concludes with five lessons that can be drawn from studying the ongoing transplant efforts.

  6. The Peri-islet Basement Membrane, a Barrier to Infiltrating Leukocytes in Type 1 Diabetes in Mouse and Human

    DEFF Research Database (Denmark)

    Korpos, Eva; Kadri, Nadir; Kappelhoff, Reinhild

    2013-01-01

    We provide the first comprehensive analysis of the extracellular matrix (ECM) composition of peri-islet capsules, composed of the peri-islet basement membrane (BM) and subjacent interstitial matrix (IM), in development of type 1 diabetes in NOD mice and in human type 1 diabetes. Our data demonstr...

  7. Interleukin 1 dose-dependently affects the biosynthesis of (pro)insulin in isolated rat islets of Langerhans

    DEFF Research Database (Denmark)

    Spinas, G A; Hansen, B S; Linde, S

    1987-01-01

    Human crude and recombinant interleukin 1 (IL-1) was found to dose- and time-dependently affect the biosynthesis of (pro)insulin in isolated rat islets of Langerhans. Incubation of rat islets with either 0.5 U/ml or 5 U/ml of crude IL-1 for 1 h had no detectable effect on (pro)insulin biosynthesis...

  8. Genetic Associations of Type 2 Diabetes with Islet Amyloid Polypeptide Processing and Degrading Pathways in Asian Populations

    NARCIS (Netherlands)

    Lam, Vincent Kwok Lim; Ma, Ronald Ching Wan; Lee, Heung Man; Hu, Cheng; Park, Kyong Soo; Furuta, Hiroto; Wang, Ying; Tam, Claudia Ha Ting; Sim, Xueling; Ng, Daniel Peng-Keat; Liu, Jianjun; Wong, Tien-Yin; Tai, E. Shyong; Morris, Andrew P.; Tang, Nelson Leung Sang; Woo, Jean; Leung, Ping Chung; Kong, Alice Pik Shan; Ozaki, Risa; Jia, Wei Ping; Lee, Hong Kyu; Nanjo, Kishio; Xu, Gang; Ng, Maggie Chor Yin; So, Wing-Yee; Chan, Juliana Chung Ngor; Ostaptchouk, Jana; Wijmenga, Cisca

    2013-01-01

    Type 2 diabetes (T2D) is a complex disease characterized by beta cell dysfunctions. Islet amyloid polypeptide (IAPP) is highly conserved and co-secreted with insulin with over 40% of autopsy cases of T2D showing islet amyloid formation due to IAPP aggregation. Dysregulation in IAPP processing,

  9. Siglec-7 restores β-cell function and survival and reduces inflammation in pancreatic islets from patients with diabetes

    NARCIS (Netherlands)

    Dharmadhikari, Gitanjali; Stolz, Katharina; Hauke, Michael; Morgan, Noel G; Varki, Ajit; de Koning, Eelco; Kelm, Sørge; Maedler, Kathrin

    2017-01-01

    Chronic inflammation plays a key role in both type 1 and type 2 diabetes. Cytokine and chemokine production within the islets in a diabetic milieu results in β-cell failure and diabetes progression. Identification of targets, which both prevent macrophage activation and infiltration into islets and

  10. Long-term inhibition of dipeptidyl peptidase IV improves glucose tolerance and preserves islet function in mice

    DEFF Research Database (Denmark)

    Reimer, M Kvist; Holst, Jens Juul; Ahrén, B

    2002-01-01

    .029) and in mice fed a high-fat diet (P=0.036). This was accompanied by increased plasma levels of insulin and intact GLP-1. Glucose-stimulated insulin secretion from islets isolated from NVP DPP728-treated animals after 8 weeks of treatment was increased as compared with islets from control animals at 5.6, 8...

  11. Expression of Receptors for Tetanus Toxin and Monoclonal Antibody A2B5 by Pancreatic Islet Cells

    Science.gov (United States)

    Eisenbarth, G. S.; Shimizu, K.; Bowring, M. A.; Wells, S.

    1982-08-01

    Studies of the reaction of antibody A2B5 and tetanus toxin with pancreatic islet cells, islet cell tumors, and other human amine precursor uptake and decarboxylation (APUD) tumors are described. By indirect immunofluorescence, antibody A2B5 and tetanus toxin were shown to specifically bind to the plasma membrane of human, rat, chicken, and mouse islet cells. The binding of antibody A2B5 to the cell surface of living islet cells has allowed isolation of these cells from a suspension of pancreatic cells by using a fluorescence-activated cell sorter. In studies designed to determine whether tetanus toxin and antibody A2B5 bound to the same surface antigen, A2B5 and tetanus toxin did not compete for binding to normal islet cells, a human islet cell tumor, or a rat islet cell tumor. In addition to binding to islet cell tumors, antibody A2B5 reacts with frozen sections, isolated cells, and cell lines of neural, neural crest, and APUD origin.

  12. Bioethics of Organ Transplantation

    Science.gov (United States)

    Caplan, Arthur

    2014-01-01

    As the ability to transplant organs and tissues has grown, the demand for these procedures has increased as well—to the point at which it far exceeds the available supply creating the core ethical challenge for transplantation—rationing. The gap between supply and demand, although large, is worse than it appears to be. There are two key steps to gaining access to a transplant. First, one must gain access to a transplant center. Then, those waiting need to be selected for a transplant. Many potential recipients do not get admitted to a program. They are deemed too old, not of the right nationality, not appropriate for transplant as a result of severe mental impairment, criminal history, drug abuse, or simply because they do not have access to a competent primary care physician who can refer them to a transplant program. There are also financial obstacles to access to transplant waiting lists in the United States and other nations. In many poor nations, those needing transplants simply die because there is no capacity or a very limited capacity to perform transplants. Although the demand for organs now exceeds the supply, resulting in rationing, the size of waiting lists would quickly expand were there to suddenly be an equally large expansion in the number of organs available for transplantation. Still, even with the reality of unavoidable rationing, saving more lives by increasing organ supply is a moral good. Current public policies for obtaining organs from cadavers are not adequate in that they do not produce the number of organs that public polls of persons in the United States indicate people are willing to donate. PMID:24478386

  13. Stepwise Approach to Problematic Hypoglycemia in Korea: Educational, Technological, and Transplant Interventions

    Directory of Open Access Journals (Sweden)

    Sang-Man Jin

    2017-06-01

    Full Text Available Impaired awareness of hypoglycemia has been found to be prevalent in 20% to 40% of people with type 1 diabetes. If a similar prevalence exists in Koreans with type 1 diabetes, at a minimum, thousands of people with type 1 diabetes suffer at least one unpredicted episode of severe hypoglycemia per year in Korea. For patients with problematic hypoglycemia, an evidence-based stepwise approach was suggested in 2015. The first step is structured education regarding multiple daily injections of an insulin analog, and the second step is adding a technological intervention, such as continuous subcutaneous insulin infusion or real-time continuous glucose monitoring. The next step is a sensor-augmented pump, preferably with a low glucose suspension feature or very frequent contact, and the final step is islet or pancreas transplantation. In Korea, however, none of these treatments are reimbursed by the National Health Insurance, and thus have not been widely implemented. The low prevalence of type 1 diabetes means that Korean physicians are relatively unfamiliar with the new technologies in this field. Therefore, the roles of new technologies and pancreas or islet transplantation in the treatment of problematic hypoglycemia need to be defined in the current clinical setting of Korea.

  14. Effects of Imatinib Mesylate (Gleevec) on Human Islet NF-kappaB Activation and Chemokine Production In Vitro

    Science.gov (United States)

    Mokhtari, Dariush; Li, Tingting; Lu, Tao; Welsh, Nils

    2011-01-01

    Purpose Imatinib Mesylate (Gleevec) is a drug that potently counteracts diabetes both in humans and in animal models for human diabetes. We have previously reported that this compound in human pancreatic islets stimulates NF-κB signaling and islet cell survival. The aim of this study was to investigate control of NF-κB post-translational modifications exerted by Imatinib and whether any such effects are associated with altered islet gene expression and chemokine production in vitro. Procedures Human islets were either left untreated or treated with Imatinib for different timepoints. IκB-α and NF-κB p65 phosphorylation and methylation were assessed by immunoblot analysis. Islet gene expression was assessed using a commercial Pathway Finder microarray kit and RT-PCR. Islet chemokine production was determined by flow cytometric bead array analysis. Findings Human islet IκB-α and Ser276-p65 phosphorylation were increased by a 20 minute Imatinib exposure. Methylation of p65 at position Lys221 was increased after 60 min of Imatinib exposure and persisted for 3 hours. Microarray analysis of islets exposed to Imatinib for 4 hours revealed increased expression of the inflammatory genes IL-4R, TCF5, DR5, I-TRAF, I-CAM, HSP27 and IL-8. The islet release of IL-8 was augmented in islets cultured over night in the presence of Imatinib. Following 30 hours of Imatinib exposure, the cytokine-induced IκB-α and STAT1 phosphorylation was abolished and diminished, respectively. The cytokine-induced release of the chemokines MIG and IP10 was lower in islets exposed to Imatinib for 30 hours. Conclusion Imatinib by itself promotes a modest activation of NF-κB. However, a prolonged exposure of human islets to Imatinib is associated with a dampened response to cytokines. It is possible that Imatinib induces NF-κB preconditioning of islet cells leading to lowered cytokine sensitivity and a mitigated islet inflammation. PMID:21935477

  15. Regulation of lipolytic activity by long-chain acyl-coenzyme A in islets and adipocytes

    DEFF Research Database (Denmark)

    Hu, Liping; Deeney, Jude T; Nolan, Christopher J

    2005-01-01

    -cells. The mechanisms by which lipolysis is regulated in different tissues is, therefore, of considerable interest. Here, the effects of long-chain acyl-CoA esters (LC-CoA) on lipase activity in islets and adipocytes were compared. Palmitoyl-CoA (Pal-CoA, 1-10 microM) stimulated lipase activity in islets from both....... The inhibitory effect of LC-CoA on adipocyte HSL was dependent on phosphorylation and enhanced by acyl-CoA-binding protein (ACBP). In contrast, the stimulatory effect on islet lipase activity was blocked by ACBP, presumably due to binding and sequestration of LC-CoA. These data suggest the following intertissue...

  16. Candidate genes expressed in human islets and their role in the pathogenesis of type 1 diabetes

    DEFF Research Database (Denmark)

    Storling, Joachim; Brorsson, Caroline Anna

    2013-01-01

    In type 1 diabetes (T1D), the insulin-producing β cells are destroyed by an immune-mediated process leading to complete insulin deficiency. There is a strong genetic component in T1D. Genes located in the human leukocyte antigen (HLA) region are the most important genetic determinants of disease......, but more than 40 additional loci are known to significantly affect T1D risk. Since most of the currently known genetic candidates have annotated immune cell functions, it is generally considered that most of the genetic susceptibility in T1D is caused by variation in genes affecting immune cell function....... Recent studies, however, indicate that most T1D candidate genes are expressed in human islets suggesting that the functions of the genes are not restricted to immune cells, but also play roles in the islets and possibly the β cells. Several candidates change expression levels within the islets following...

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

    DEFF Research Database (Denmark)

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

    1985-01-01

    Cytokines are soluble, antigen non-specific, non-immunoglobulin mediators produced and secreted by blood mononuclear cells interacting in the cellular immune-response. To test the possibility that cytokines participate in the autoimmune destruction of the pancreatic beta-cells leading to insulin......-dependent diabetes mellitus, isolated human or rat islets of Langerhans were incubated for 7 days with cytokine-rich, cell-free supernatants of blood mononuclear cells from healthy human donors stimulated with or without purified protein derivative of tuberculin or phytohaemagglutinin. Glucose stimulated insulin......-release, and contents of insulin and glucagon in islets incubated with cytokine-rich supernatants were markedly reduced. This impairment of islet function was due to a cytotoxic effect of cytokine-rich supernatants as judged by disintegration of normal light-microscopic morphology....

  18. 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...... 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...

  19. 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...... from βGlud1(-/-) mice resulted in abrogation of insulin release evoked by glutamine combined with 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid or l-leucine. Reintroduction of GDH in βGlud1(-/-) islets fully restored the secretory response. Regarding glucose stimulation, insulin secretion in islets...... isolated from βGlud1(-/-) mice exhibited half of the response measured in control islets. The amplifying pathway, tested at stimulatory glucose concentrations in the presence of KCl and diazoxide, was markedly inhibited in βGlud1(-/-) islets. On glucose stimulation, net synthesis of glutamate from α...

  20. Stimulatory effect of serum from diabetic patients on insulin release from mouse pancreatic islets maintained in tissue culture

    DEFF Research Database (Denmark)

    Eff, C; Deckert, T; Andersson, A

    1981-01-01

    Islets of Langerhans from NMRI-mice were kept for one week in tissue culture in medium supplemented with human serum obtained from either normal healthy subjects or newly diagnosed juvenile diabetic patients before insulin treatment. Islets cultured in diabetic serum released more insulin than...... islets cultured in normal serum, whether tissue culture medium 199 with 5.5-8.3 mmol/l glucose and 10% serum, or culture medium RPMI 1640 with 11 mmol/l glucose and 0.5% serum were used. Islets kept for one week in culture with diabetic serum did not show any decrease in DNA content or glucose induced...... insulin secretion and biosynthesis. It is concluded that serum from newly diagnosed insulin-dependent diabetic patients stimulates insulin release from isolated mouse islets kept in tissue culture. The underlying mechanism is unknown....

  1. Systematic comparison of sporadic and syndromic pancreatic islet cell tumors.

    Science.gov (United States)

    Erlic, Zoran; Ploeckinger, Ursula; Cascon, Alberto; Hoffmann, Michael M; von Duecker, Laura; Winter, Aurelia; Kammel, Gerit; Bacher, Janina; Sullivan, Maren; Isermann, Berend; Fischer, Lars; Raffel, Andreas; Knoefel, Wolfram Trudo; Schott, Matthias; Baumann, Tobias; Schaefer, Oliver; Keck, Tobias; Baum, Richard P; Milos, Ioana; Muresan, Mihaela; Peczkowska, Mariola; Januszewicz, Andrzej; Cupisti, Kenko; Tönjes, Anke; Fasshauer, Mathias; Langrehr, Jan; von Wussow, Peter; Agaimy, Abbas; Schlimok, Günter; Lamberts, Regina; Wiech, Thorsten; Schmid, Kurt Werner; Weber, Alexander; Nunez, Mercedes; Robledo, Mercedes; Eng, Charis; Neumann, Hartmut P H

    2010-12-01

    Pancreatic islet cell tumors (ICTs) occur as sporadic neoplasias or as a manifestation of multiple endocrine neoplasia type 1 (MEN1) and von Hippel-Lindau disease (VHL). Molecular classification of ICTs is mandatory for timely diagnosis and surveillance. Systematic comparison of VHL-ICTs and sporadic ICTs has been lacking. Our registry-based approaches used the German NET-Registry with 259 patients with neuroendocrine tumors (NETs), who were primarily diagnosed with NETs, and the German VHL-Registry with 485 molecular genetically confirmed patients who had undergone magnetic resonance imaging or computed tomography of the abdomen. All patients provided blood DNA for testing of the MEN1 and VHL genes for intragenic mutations and large deletions. In the NET-Registry, 9/101 patients (8.9%) with ICTs had germline mutations, 8 in MEN1 and 1 in VHL. In the VHL-Registry, prevalence of NETs was 52/487 (10.6%), and all were ICTs. Interestingly, of those with VHL p.R167W, 47% developed ICTs, compared to 2% of those with p.Y98H. In total, there were 92 truly sporadic, i.e. mutation-negative ICT patients. Comparing these with the 53 VHL-ICT patients, the statistically significant differences were predominance of female gender (P=0.01), multifocal ICTs (P=0.0029), and lower malignancy rate (PICTs compared to sporadic cases. VHL was prevalent in ICTs, which are rarely the first presentation. Patients with NETs should not be subjected to genetic testing of the VHL gene, unless they have multifocal ICTs, other VHL-associated tumors, and/or a family history for VHL.

  2. Early Infant Diet and Islet Autoimmunity in the TEDDY Study.

    Science.gov (United States)

    Uusitalo, Ulla; Lee, Hye-Seung; Andrén Aronsson, Carin; Vehik, Kendra; Yang, Jimin; Hummel, Sandra; Silvis, Katherine; Lernmark, Åke; Rewers, Marian; Hagopian, William; She, Jin-Xiong; Simell, Olli; Toppari, Jorma; Ziegler, Anette-G; Akolkar, Beena; Krischer, Jeffrey; Virtanen, Suvi M; Norris, Jill M

    2018-03-01

    To examine duration of breastfeeding and timing of complementary foods and risk of islet autoimmunity (IA). The Environmental Determinants of Diabetes in the Young (TEDDY) study prospectively follows 8,676 children with increased genetic risk of type 1 diabetes (T1D) in the U.S., Finland, Germany, and Sweden. This study included 7,563 children with at least 9 months of follow-up. Blood samples were collected every 3 months from birth to evaluate IA, defined as persistent, confirmed positive antibodies to insulin (IAAs), GAD, or insulinoma antigen-2. We examined the associations between diet and the risk of IA using Cox regression models adjusted for country, T1D family history, HLA genotype, sex, and early probiotic exposure. Additionally, we investigated martingale residuals and log-rank statistics to determine cut points for ages of dietary exposures. Later introduction of gluten was associated with increased risk of any IA and IAA. The hazard ratios (HRs) for every 1-month delay in gluten introduction were 1.05 (95% CI 1.01, 1.10; P = 0.02) and 1.08 (95% CI 1.00, 1.16; P = 0.04), respectively. Martingale residual analysis suggested that the age at gluten introduction could be grouped as 9 months. The risk of IA associated with introducing gluten before 4 months of age was lower (HR 0.68; 95% CI 0.47, 0.99), and the risk of IA associated with introducing it later than the age of 9 months was higher (HR 1.57; 95% CI 1.07, 2.31) than introduction between 4 and 9 months of age. The timing of gluten-containing cereals and IA should be studied further. © 2018 by the American Diabetes Association.

  3. Plasma 25-Hydroxyvitamin D Concentration and Risk of Islet Autoimmunity.

    Science.gov (United States)

    Norris, Jill M; Lee, Hye-Seung; Frederiksen, Brittni; Erlund, Iris; Uusitalo, Ulla; Yang, Jimin; Lernmark, Åke; Simell, Olli; Toppari, Jorma; Rewers, Marian; Ziegler, Anette-G; She, Jin-Xiong; Onengut-Gumuscu, Suna; Chen, Wei-Min; Rich, Stephen S; Sundvall, Jouko; Akolkar, Beena; Krischer, Jeffrey; Virtanen, Suvi M; Hagopian, William

    2018-01-01

    We examined the association between plasma 25-hydroxyvitamin D [25(OH)D] concentration and islet autoimmunity (IA) and whether vitamin D gene polymorphisms modify the effect of 25(OH)D on IA risk. We followed 8,676 children at increased genetic risk of type 1 diabetes at six sites in the U.S. and Europe. We defined IA as positivity for at least one autoantibody (GADA, IAA, or IA-2A) on two or more visits. We conducted a risk set sampled nested case-control study of 376 IA case subjects and up to 3 control subjects per case subject. 25(OH)D concentration was measured on all samples prior to, and including, the first IA positive visit. Nine polymorphisms in VDR , CYP24A, CYP27B1, GC, and RXRA were analyzed as effect modifiers of 25(OH)D. Adjusting for HLA-DR-DQ and ancestry, higher childhood 25(OH)D was associated with lower IA risk (odds ratio = 0.93 for a 5 nmol/L difference; 95% CI 0.89, 0.97). Moreover, this association was modified by VDR rs7975232 (interaction P = 0.0072), where increased childhood 25(OH)D was associated with a decreasing IA risk based upon number of minor alleles: 0 (1.00; 0.93, 1.07), 1 (0.92; 0.89, 0.96), and 2 (0.86; 0.80, 0.92). Vitamin D and VDR may have a combined role in IA development in children at increased genetic risk for type 1 diabetes. © 2017 by the American Diabetes Association.

  4. Effect of Amorphophallus Konjac oligosaccharides on STZ-induced diabetes model of isolated islets.

    Science.gov (United States)

    Lu, Xiu-Ju; Chen, Xiu-Min; Fu, De-Xian; Cong, Wei; Ouyang, Fan

    2002-12-27

    Three oligosaccharide fractions from the root of Amorphophallus Konjac, which was reported with hypoglycemic effects on diabetes subjects, were isolated and studied using the STZ-treated diabetes model. Among them, one fraction named as KOS-A, was found with nitric oxide (NO(*)) free radical regulation effect, while the other two were not. At concentrations less than 1.5 mM, KOS-A positively decreased STZ-induced NO(*) level of islets, but normal NO(*) release for non-STZ-treated islets was not affected within the range. At 15 mM, KOS-A played a contrary role and increased NO(*) level for islets both with and without STZ-treatment. Islets insulin secretion changed corresponding to NO(*) level in the assay. Increased insulin secretion appeared parallel to the decrease of NO(*), and normal insulin release was not affected by KOS-A less than 1.5 mM. Structure determination of KOS-A shows that it is a tetrasaccharide with Mw of 666 Da and reductive end of alpha-D-mannose. These results indicate that low dosage of KOS-A, with its function on attenuating STZ-induced NO(*) level, doesn't alter normal NO(*) and insulin secretion pathways of isolated islets. The NO(*) attenuation function of KOS-A on the diabetes model is mainly resulted from environmental free radical scavenging by the oligosaccharide. Present results also imply the mechanism of clinical Amorphophallus Konjac hypoglycemic function maybe related with free radical attenuation and lower risks of islets damage from NO(*) radical.

  5. Syngeneic transplantation in aplastic anemia

    DEFF Research Database (Denmark)

    Gerull, Sabine; Stern, Martin; Apperley, Jane

    2013-01-01

    Aplastic anemia is usually treated with immunosuppression or allogeneic transplant, depending on patient and disease characteristics. Syngeneic transplant offers a rare treatment opportunity with minimal transplant-related mortality, and offers an insight into disease mechanisms. We present here...... a retrospective analysis of all syngeneic transplants for aplastic anemia reported to the European Group for Blood and Marrow Transplantation. Between 1976 and 2009, 88 patients received 113 transplants. Most transplants (n=85) were preceded by a conditioning regimen, 22 of these including anti-thymocyte globulin...

  6. Autoimmunity against INS-IGF2 expressed in human pancreatic islets.

    OpenAIRE

    Kanatsuna, Norio; Taneera, Jalal; Vaziri Sani, Fariba; Wierup, Nils; Larsson, Helena; Delli, Ahmed; Skärstrand, Hanna; Balhuizen, Alexander; Bennet, Hedvig; Steiner, Donald F; Törn, Carina; Fex, Malin; Lernmark, Åke

    2013-01-01

    Insulin is a major autoantigen in islet autoimmunity and progression to type 1 diabetes. It has been suggested that the insulin B-chain may be critical to insulin autoimmunity in type 1 diabetes. INS-IGF2 consists of the preproinsulin signal peptide, the insulin B-chain and eight amino acids of the C-peptide in addition to 138 amino acids from the IGF2 gene. We aimed to determine 1) expression of INS-IGF2 in human pancreatic islets and 2) autoantibodies in newly diagnosed type 1 diabetes chil...

  7. Interleukin-1beta induced changes in the protein expression of rat islets: a computerized database

    DEFF Research Database (Denmark)

    Andersen, H U; Fey, S J; Larsen, Peter Mose

    1997-01-01

    ) the determination of the effects of agents modulating cytokine action, and (iii) the identification of primary islet protein antigen(s) initiating the immune destruction of the beta-cells. Therefore, the aim of this study was to create databases (DB) of all reproducibly detectable protein spots on 10% and 15......% of %IOD was 45.7% in the NEPHGE gels. Addition of interleukin-1beta (IL-1beta) to the cultures resulted in statistically significant modulation or de novo synthesis of 105 proteins in the 10% gels. In conclusion, we present the first 10% and 15% acrylamide 2-D gel protein databases of neonatal rat islets...

  8. 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...... reduced the insulin biosynthesis to 6.1 +/- 2.7% (n = 4). During the 3 h labelling period the labelled proinsulin content compared to insulin was increased from 9.0 +/- 1.3% (control) to 26.6 +/- 6.4% in the IL-1 exposed islets, and the ratio between labelled insulin 1 to 2 was increased from 2.0 +/- 0...

  9. Gene expression in rat models for inter-generational transmission of islet dysfunction and obesity

    Directory of Open Access Journals (Sweden)

    Ruby C.Y. Lin

    2014-12-01

    Full Text Available Paternal high fat diet (HFD consumption triggers unique gene signatures, consistent with premature aging and chronic degenerative disorders, in both white adipose tissue (RpWAT and pancreatic islets of daughters. In addition to published data in Nature, 2010, 467, 963–966 (GSE: 19877, islet and FASEB J 2014, 28, 1830–1841 (GSE: 33551, RpWAT, we describe here additional details on systems-based approaches and analysis to develop our observations. Our data provides a resource for exploring the complex molecular mechanisms that underlie intergenerational transmission of obesity.

  10. Some application with LIDAR data for Fermecatu Islet (Călărasi county, Romania

    Directory of Open Access Journals (Sweden)

    MIERLĂ Marian

    2009-09-01

    Full Text Available This paper presents some possibilities of applications of the LIDAR data. As a case study is used an islet on the Danube River closed to Calarasi town, Fermecatu islet. In the first part it is presented a way to handle the LIDAR transformed data and the creation of a digital terrain model (DTM. Later on there are presented some useful and facile application of using DTM. The data that were used in present paper derive from a big project named: “The Danube River, Lower Floodplain, ecological and economical resizing”, financedby the Ministry of Environment.

  11. Longitudinal plasma metabolic profiles, infant feeding, and islet autoimmunity in the MIDIA study

    DEFF Research Database (Denmark)

    Jørgenrud, Benedicte; Stene, Lars C; Tapia, German

    2017-01-01

    Aims: The aim of this study was to investigate the longitudinal plasma metabolic profiles in healthy infants and the potential association with breastfeeding duration and islet autoantibodies predictive of type 1 diabetes. Method: Up to four longitudinal plasma samples from age 3 months from case......-chain amino acids, and lower levels of methionine and 3,4-dihydroxybutyric acid.......Aims: The aim of this study was to investigate the longitudinal plasma metabolic profiles in healthy infants and the potential association with breastfeeding duration and islet autoantibodies predictive of type 1 diabetes. Method: Up to four longitudinal plasma samples from age 3 months from case...

  12. Islet cell hyperexpression of HLA class I antigens: a defining feature in type 1 diabetes.

    Science.gov (United States)

    Richardson, Sarah J; Rodriguez-Calvo, Teresa; Gerling, Ivan C; Mathews, Clayton E; Kaddis, John S; Russell, Mark A; Zeissler, Marie; Leete, Pia; Krogvold, Lars; Dahl-Jørgensen, Knut; von Herrath, Matthias; Pugliese, Alberto; Atkinson, Mark A; Morgan, Noel G

    2016-11-01

    Human pancreatic beta cells may be complicit in their own demise in type 1 diabetes, but how this occurs remains unclear. One potentially contributing factor is hyperexpression of HLA class I antigens. This was first described approximately 30 years ago, but has never been fully characterised and was recently challenged as artefactual. Therefore, we investigated HLA class I expression at the protein and RNA levels in pancreases from three cohorts of patients with type 1 diabetes. The principal aims were to consider whether HLA class I hyperexpression is artefactual and, if not, to determine the factors driving it. Pancreas samples from type 1 diabetes patients with residual insulin-containing islets (n = 26) from the Network for Pancreatic Organ donors with Diabetes (nPOD), Diabetes Virus Detection study (DiViD) and UK recent-onset type 1 diabetes collections were immunostained for HLA class I isoforms, signal transducer and activator of transcription 1 (STAT1), NLR family CARD domain containing 5 (NLRC5) and islet hormones. RNA was extracted from islets isolated by laser-capture microdissection from nPOD and DiViD samples and analysed using gene-expression arrays. Hyperexpression of HLA class I was observed in the insulin-containing islets of type 1 diabetes patients from all three tissue collections, and was confirmed at both the RNA and protein levels. The expression of β2-microglobulin (a second component required for the generation of functional HLA class I complexes) was also elevated. Both 'classical' HLA class I isoforms (i.e. HLA-ABC) as well as a 'non-classical' HLA molecule, HLA-F, were hyperexpressed in insulin-containing islets. This hyperexpression did not correlate with detectable upregulation of the transcriptional regulator NLRC5. However, it was strongly associated with increased STAT1 expression in all three cohorts. Islet hyperexpression of HLA class I molecules occurred in the insulin-containing islets of patients with recent-onset type 1

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

    DEFF Research Database (Denmark)

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

    1985-01-01

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

  14. Lagoon islets as indicators of recent environmental changes in the South Pacific - The New Caledonian example

    Science.gov (United States)

    Garcin, Manuel; Vendé-Leclerc, Myriam; Maurizot, Pierre; Le Cozannet, Gonéri; Robineau, Bernard; Nicolae-Lerma, Alexandre

    2016-07-01

    The question of the impacts of climate change and sea level rise on small islands is currently much discussed. The many thousands of Pacific islands in their different contexts (geodynamic, climatic, etc.) and the insufficient data available explain why it is difficult to clearly discern the specific role of climate change in the recent evolution of these islands. To address this question, we investigated the recent changes affecting 21 islets in New Caledonia's lagoon. These islets are either located on small patch-reefs inside the New Caledonia Island lagoon or lie directly on the barrier reef. Based on the studies we conducted (field surveys, reconstruction of changes in the islets over the last decades, shoreline changes) we were able to define a typology of the islets that includes 6 stages and a life expectancy index. Using the life expectancy index, we found that of the 21 islets studied, 19% are in a highly critical situation, meaning they are very likely to be endangered in the short term (within the next few years), 9.5% are in a critical situation, i.e., likely to disappear in the near future and very likely to disappear in the medium term (next few decades), 19% are evolving rapidly, which could lead to their disappearance in the medium term but not in the short term, 9.5% are not endangered in the short and medium term and 43% are not endangered at all (stable or accreting, large area, relatively higher altitude). In this context, the rise in sea level induced by climate change is an adverse factor which is likely to lower the resilience of the islets to erosion processes. Other factors like the degradation of the reef ecosystem due to variations in ocean salinity, temperature and acidity, lower sediment stocks on the beaches and foreshores, human visitors, coastal development and so on are other adverse factors that could modify the capacity for resilience of these islets. Due to their variety and sensitivity, New Caledonia's islets could thus serve

  15. Association of Early Exposure of Probiotics and Islet Autoimmunity in the TEDDY Study.

    Science.gov (United States)

    Uusitalo, Ulla; Liu, Xiang; Yang, Jimin; Aronsson, Carin Andrén; Hummel, Sandra; Butterworth, Martha; Lernmark, Åke; Rewers, Marian; Hagopian, William; She, Jin-Xiong; Simell, Olli; Toppari, Jorma; Ziegler, Anette G; Akolkar, Beena; Krischer, Jeffrey; Norris, Jill M; Virtanen, Suvi M

    2016-01-01

    Probiotics have been hypothesized to affect immunologic responses to environmental exposures by supporting healthy gut microbiota and could therefore theoretically be used to prevent the development of type 1 diabetes mellitus (T1DM)-associated islet autoimmunity. To examine the association between supplemental probiotic use during the first year of life and islet autoimmunity among children at increased genetic risk of T1DM. In this ongoing prospective cohort study that started September 1, 2004, children from 6 clinical centers, 3 in the United States (Colorado, Georgia/Florida, and Washington) and 3 in Europe (Finland, Germany, and Sweden), were followed up for T1DM-related autoantibodies. Blood samples were collected every 3 months between 3 and 48 months of age and every 6 months thereafter to determine persistent islet autoimmunity. Details of infant feeding, including probiotic supplementation and infant formula use, were monitored from birth using questionnaires and diaries. We applied time-to-event analysis to study the association between probiotic use and islet autoimmunity, stratifying by country and adjusting for family history of type 1 diabetes, HLA-DR-DQ genotypes, sex, birth order, mode of delivery, exclusive breastfeeding, birth year, child's antibiotic use, and diarrheal history, as well as maternal age, probiotic use, and smoking. Altogether 8676 infants with an eligible genotype were enrolled in the follow-up study before the age of 4 months. The final sample consisted of 7473 children with the age range of 4 to 10 years (as of October 31, 2014). Early intake of probiotics. Islet autoimmunity revealed by specific islet autoantibodies. Early probiotic supplementation (at the age of 0-27 days) was associated with a decreased risk of islet autoimmunity when compared with probiotic supplementation after 27 days or no probiotic supplementation (hazard ratio [HR], 0.66; 95% CI, 0.46-0.94). The association was accounted for by children with the DR3

  16. 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 cytotoxic activity was eliminated from crude cytokine preparations by adsorption with immobilized, purified antibody to interleukin-1 (IL-1). The islet-inhibitory activity and the IL-1 activity (determined by its comitogenic effect on thymocytes) were recovered by acid wash. Purified natural IL-1...

  17. Binding of [125I] Concanavalin A to isolated Langerhans islets of rats

    International Nuclear Information System (INIS)

    Prey, N.

    1983-01-01

    Langerhans islets of rats were isolated using Lacy's collagenase technique and were incubated in vitro. The binding of iodine-labelled Concanavalin A to isolated Langerhans islets was investigated. We were unable to decide whether multiple Concanavalin A binding sites are located on the cell membrane, or whether the Concanavalin A binding sites are negatively influenced via a allosteric protein. Although the secretion mechanism induced by sulfony urea is not influenced by Concanavalin A, enhanced binding of Concanavalin A indicates that the region of identification cannot be identical for glucose and sulfonyl urea. (orig./MG) [de

  18. [Surgical techniques of organ transplants].

    Science.gov (United States)

    Froněk, Jiří

    2015-01-01

    The list of surgical procedures of solid organ transplantations appears very interesting and colorful, even with overlap among techniques. Liver transplantation is a life-saving procedure in a majority of cases, the liver can be transplanted as a full or partial graft. The liver graft can be split for two recipients; it can also be reduced for a small recipient if splitting is not indicated. Kidney transplantation is the most common solid organ transplant procedure, the majority of kidney grafts come from brain-dead donors whereas the number of live donor transplants is increasing, also thanks to paired donation and blood group incompatible transplantation methods. The small bowel and multivisceral transplantation are rare procedures; they serve selected patients with short bowel syndrome, some patients with retroperitoneal tumors or with extensive visceral thrombosis. Solid organ transplants are well established treatment methods with good and proven outcomes. A majority of patients can return to a normal life after their transplants.

  19. Donor transplant programme

    International Nuclear Information System (INIS)

    Abu Bakar Sulaiman

    1999-01-01

    The transplantation of organs and tissues from one human to another human has become an essential and well established form of therapy for many types of organ and tissue failure. In Malaysia, kidney, cornea and bone marrow transplantation are well established. Recently, liver, bone and heart transplanation have been performed. Unfortunately, because of the lack of cadaveric organ donation, only a limited number of solid organ transplantation have been performed. The cadaveric organ donor rate in Malaysia is low at less than one per million population. The first tissue transplanted in Malaysia was the cornea which was performed in the early 1970s. At that time and even now the majority of corneas came from Sri Lanka. The first kidney transplant was performed in 1975 from a live related donor. The majority of the 629 kidney transplants done at Hospital Kuala Lumpur to date have been from live related donors. Only 35 were from cadaver donors. Similarly, the liver transplantation programme which started in 1995 are from live related donors. A more concerted effort has been made recently to increase the awareness of the public and the health professionals on organ and tissue donation. This national effort to promote organ and tissue donation seems to have gathered momentum in 1997 with the first heart transplant successfully performed at the National Heart Institute. The rate of cadaveric donors has also increased from a previous average of I to 2 per year to 6 per year in the last one year. These developments are most encouraging and may signal the coming of age of our transplantati on programme. The Ministry of Health in conjunction with various institutions, organizations and professional groups, have taken a number of proactive measures to facilitate the development of the cadaveric organ donation programme. Efforts to increase public awareness and to overcome the negative cultural attitude towards organ donation have been intensified. Equally important are efforts

  20. [Pregnancy after renal transplantation].

    Science.gov (United States)

    Zech, H; Bichler, A; Ortner, A

    1981-12-01

    Since the number of women with renal cadaver transplantation is increasing, the obstetrician seems himself more often confronted with the situation: pregnancy after renal transplantation. The purpose of this paper is to report about our own case, to give a review of international studies written on this subject, and to inform the obstetrician, the surgeon and the pediatrician about the following points: - Common aspects of renal transplantation in fertile women and the information to be given to the patient. - Selection criteria and anticonception. - Pregnancy assessment and delivery - Pediatric problems.

  1. Repeated Gene Transfection Impairs the Engraftment of Transplanted Porcine Neonatal Pancreatic Cells

    Directory of Open Access Journals (Sweden)

    Min Koo Seo

    2011-02-01

    Full Text Available BackgroundPreviously, we reported that neonatal porcine pancreatic cells transfected with hepatocyte growth factor (HGF gene in an Epstein-Barr virus (EBV-based plasmid (pEBVHGF showed improved proliferation and differentiation compared to those of the control. In this study, we examined if pancreatic cells transfected repeatedly with pEBVHGF can be successfully grafted to control blood glucose in a diabetes mouse model.MethodsNeonatal porcine pancreatic cells were cultured as a monolayer and were transfected with pEBVHGF every other day for a total of three transfections. The transfected pancreatic cells were re-aggregated and transplanted into kidney capsules of diabetic nude mice or normal nude mice. Blood glucose level and body weight were measured every other day after transplantation. The engraftment of the transplanted cells and differentiation into beta cells were assessed using immunohistochemistry.ResultsRe-aggregation of the pancreatic cells before transplantation improved engraftment of the cells and facilitated neovascularization of the graft. Right before transplantation, pancreatic cells that were transfected with pEBVHGF and then re-aggregated showed ductal cell marker expression. However, ductal cells disappeared and the cells underwent fibrosis in a diabetes mouse model two to five weeks after transplantation; these mice also did not show controlled blood glucose levels. Furthermore, pancreatic cells transplanted into nude mice with normal blood glucose showed poor graft survival regardless of the type of transfected plasmid (pCEP4, pHGF, or pEBVHGF.ConclusionFor clinical application of transfected neonatal porcine pancreatic cells, further studies are required to develop methods of overcoming the damage for the cells caused by repeated transfection and to re-aggregate them into islet-like structures.

  2. 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......-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....../islet) than in adult rat islets, which, however, increased their content from 1.3 +/- 0.5 to 7.0 +/- 0.5 fmol/islet during the first 3 d of culture. Adult rat islets maintained in medium with 20 mM glucose released significantly more TRH-IR than islets in 3.3 mM glucose medium (13.0 +/- 0.7 vs. 4.3 +/- 0...

  3. Bone marrow transplant

    Science.gov (United States)

    ... cure your illness. If the transplant is a success, you can go back to most of your ... ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer Support Get email updates Subscribe to RSS Follow ...

  4. Kidney Transplantation in Iran

    Directory of Open Access Journals (Sweden)

    Behzad Einollahi

    2010-03-01

    Full Text Available Kidney transplantation in patients with end stage renal diseaseis preferred to dialysis because transplantation provides a betterquality of life and improved survival. However, the gapbetween the supply and demand for a renal allograft is wideningand the waiting time is increasing. Iranian protocol, a controlledtransplant program supported by the government forliving unrelated donors, was initiated for solving the problemof organ shortage. Although this system might experiencechallenges, clearly it has advantages over other organ procurementsystems primarily that thousands in need do not diewhile waiting for a compatible donor.In the present review I discuss the history of renal transplantationin Iran, "Iranian model" protocol, the situation ofIran’s kidney transplantation from either living or deceaseddonors compared with the Middle East countries, and our experiencesof unrelated renal transplantation.

  5. Rabies in Transplant Recipients

    Centers for Disease Control (CDC) Podcasts

    2016-09-19

    Dr. Richard Franka, a CDC scientist, discusses rabies in organ transplant recipients.  Created: 9/19/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 9/19/2016.

  6. Frailty and Transplantation

    NARCIS (Netherlands)

    Exterkate, Leonie; Slegtenhorst, Bendix R.; Kelm, Matthias; Seyda, Midas; Schuitenmaker, Jeroen M.; Quante, Markus; Uehara, Hirofumi; El Khal, Abdala; Tullius, Stefan G.

    Consequences of aging are gaining clinical relevance. In transplantation, aging and immunosenescence impact treatment and outcomes. The impact of aging, however, will critically depend on distinguishing healthy, chronological aging from biological aging that may result into frailty. Approximately

  7. Liver transplant - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100090.htm Liver transplant - series—Normal anatomy To use the sharing ... to slide 5 out of 5 Overview The liver is in the right upper abdomen. The liver ...

  8. Imaging in transplantation

    International Nuclear Information System (INIS)

    Bankier, A.A.

    2008-01-01

    This book covers all topics related to the imaging of organ transplantation. An introductory section addresses such issues as organ procurement, patient selection, immune responses, and ethical and economic considerations. The main part of the book then offers in-depth coverage of heart, renal, liver, lung, bone marrow and pancreatic and intestinal transplantation. Each of these topics is discussed firstly in a clinical chapter and then in a radiological chapter. The clinical chapters detail the epidemiology, clinical background, and surgical procedures, as well as any clinically relevant issues of which the radiologist should be aware. The radiological chapters describe and depict the imaging manifestations of specific organ transplantations, document the normal radiological appearance of transplanted organs and consider both early and late complications. This is a unique, superbly illustrated volume that will be of great assistance to all who work in this field. (orig.)

  9. International Transplant Nurses Society

    Science.gov (United States)

    ... The term "clinical ladder" refers to a "grading structure which facilitates career progression and associated differentiation of ... 20-1589538 Copyright © 2006 - 2014 International Transplant Nurses Society (ITNS). No materials, including graphics, may be reused, ...

  10. Experimental uterus transplantation.

    Science.gov (United States)

    Johannesson, Liza; Enskog, Anders

    2014-11-01

    Today, most causes of infertility are successfully treated. Yet there is still a subgroup of female infertility affecting around 4%, which so far is untreatable because of an absolute uterine factor. To acquire motherhood, these women are today referred to either adoption or surrogacy. Research in the field of uterus transplantation has been evaluated in different animal models for decades and has presently reached a human clinical application as a possible treatment for absolute uterine factor infertility. Organ transplantation is no longer reserved to those with a life-threatening disease and neither is organ transplantation together with concurrent immunosuppression prohibiting pregnancy. Uterus transplantation involves four parties - recipient, donor, partner of recipient and future child - and is a subject of ethical controversies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Bone marrow transplant - discharge

    Science.gov (United States)

    ... lymphoblastic leukemia (ALL) Acute myeloid leukemia - adult Aplastic anemia Bone marrow transplant Chronic lymphocytic leukemia (CLL) Chronic myelogenous leukemia (CML) Graft-versus-host disease Hodgkin lymphoma Multiple myeloma Non-Hodgkin lymphoma Patient ...

  12. Fecal microbiota transplant

    Science.gov (United States)

    ... nih.gov/pubmed/26344412 . Surawicz CM, Brandt LJ. Probiotics and fecal microbiota transplantation. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 10th ed. Philadelphia, PA: Elsevier ...

  13. Livebirth after uterus transplantation.

    Science.gov (United States)

    Brännström, Mats; Johannesson, Liza; Bokström, Hans; Kvarnström, Niclas; Mölne, Johan; Dahm-Kähler, Pernilla; Enskog, Anders; Milenkovic, Milan; Ekberg, Jana; Diaz-Garcia, Cesar; Gäbel, Markus; Hanafy, Ash; Hagberg, Henrik; Olausson, Michael; Nilsson, Lars

    2015-02-14

    Uterus transplantation is the first available treatment for absolute uterine infertility, which is caused by absence of the uterus or the presence of a non-functional uterus. Eleven human uterus transplantation attempts have been done worldwide but no livebirth has yet been reported. In 2013, a 35-year-old woman with congenital absence of the uterus (Rokitansky syndrome) underwent transplantation of the uterus in Sahlgrenska University Hospital, Gothenburg, Sweden. The uterus was donated from a living, 61-year-old, two-parous woman. In-vitro fertilisation treatment of the recipient and her partner had been done before transplantation, from which 11 embryos were cryopreserved. The recipient and the donor had essentially uneventful postoperative recoveries. The recipient's first menstruation occurred 43 days after transplantation and she continued to menstruate at regular intervals of between 26 and 36 days (median 32 days). 1 year after transplantation, the recipient underwent her first single embryo transfer, which resulted in pregnancy. She was then given triple immunosuppression (tacrolimus, azathioprine, and corticosteroids), which was continued throughout pregnancy. She had three episodes of mild rejection, one of which occurred during pregnancy. These episodes were all reversed by corticosteroid treatment. Fetal growth parameters and blood flows of the uterine arteries and umbilical cord were normal throughout pregnancy. The patient was admitted with pre-eclampsia at 31 full weeks and 5 days, and 16 h later a caesarean section was done because of abnormal cardiotocography. A male baby with a normal birthweight for gestational age (1775 g) and with APGAR scores 9, 9, 10 was born. We describe the first livebirth after uterus transplantation. This report is a proof-of-concept for uterus transplantation as a treatment for uterine factor infertility. Furthermore, the results show the feasibility of live uterus donation, even from a postmenopausal donor. Jane and

  14. Faecal microbiota transplantation

    DEFF Research Database (Denmark)

    Jørgensen, Simon M D; Hansen, Mette Mejlby; Erikstrup, Christian

    2017-01-01

    BACKGROUND: Faecal microbiota transplantation (FMT) is currently being established as a second-line treatment for recurrent Clostridium difficile infection. FMT is further being considered for other infectious and inflammatory conditions. Safe and reproducible methods for donor screening, laborat......BACKGROUND: Faecal microbiota transplantation (FMT) is currently being established as a second-line treatment for recurrent Clostridium difficile infection. FMT is further being considered for other infectious and inflammatory conditions. Safe and reproducible methods for donor screening...

  15. Immunosuppression in lung transplantation.

    Science.gov (United States)

    Scheffert, Jenna L; Raza, Kashif

    2014-08-01

    Lung transplantation can be a life-saving procedure for those with end-stage lung diseases. Unfortunately, long term graft and patient survival are limited by both acute and chronic allograft rejection, with a median survival of just over 6 years. Immunosuppressive regimens are employed to reduce the rate of rejection, and while protocols vary from center to center, conventional maintenance therapy consists of triple drug therapy with a calcineurin inhibitor (cyclosporine or tacrolimus), antiproliferative agents [azathioprine (AZA), mycophenolate, sirolimus (srl), everolimus (evl)], and corticosteroids (CS). Roughly 50% of lung transplant centers also utilize induction therapy, with polyclonal antibody preparations [equine or rabbit anti-thymocyte globulin (ATG)], interleukin 2 receptor antagonists (IL2RAs) (daclizumab or basiliximab), or alemtuzumab. This review summarizes these agents and the data surrounding their use in lung transplantation, as well as additional common and novel therapies in lung transplantation. Despite the progression of the management of lung transplant recipients, they continue to be at high risk of treatment-related complications, and poor graft and patient survival. Randomized clinical trials are needed to allow for the development of better agents, regimens and techniques to address above mentioned issues and reduce morbidity and mortality among lung transplant recipients.

  16. Hematopoietic stem cell transplantation

    Directory of Open Access Journals (Sweden)

    Eleftheria Hatzimichael

    2010-08-01

    Full Text Available Eleftheria Hatzimichael1, Mark Tuthill21Department of Haematology, Medical School of Ioannina, University of Ioannina, Ioannina, Greece; 2Department of Medical Oncology, Hammersmith Hospital, Imperial College National Health Service Trust, London, UKAbstract: More than 25,000 hematopoietic stem cell transplantations (HSCTs are performed each year for the treatment of lymphoma, leukemia, immune-deficiency illnesses, congenital metabolic defects, hemoglobinopathies, and myelodysplastic and myeloproliferative syndromes. Before transplantation, patients receive intensive myeloablative chemoradiotherapy followed by stem cell “rescue.” Autologous HSCT is performed using the patient’s own hematopoietic stem cells, which are harvested before transplantation and reinfused after myeloablation. Allogeneic HSCT uses human leukocyte antigen (HLA-matched stem cells derived from a donor. Survival after allogeneic transplantation depends on donor–recipient matching, the graft-versus-host response, and the development of a graft versus leukemia effect. This article reviews the biology of stem cells, clinical efficacy of HSCT, transplantation procedures, and potential complications.Keywords: hematopoietic stem cell transplantation, complications

  17. Indian transplant registry

    Directory of Open Access Journals (Sweden)

    Sunil Shroff

    2007-01-01

    Full Text Available An ′Indian transplant registry′ has been established over the past two years due to the efforts of the Indian Society of Organ Transplantation. This society is about 20 years old with over 450 members who are doctors and basic scientist. The registry is currently in the first phase of its development and can be partly viewed at www.transplantindia.com. The endeavor has been undertaken with the objective of having a centralized repository of information of the various transplants that are being undertaken in India. In its first phase of the registry ′Fast Fact′ retrospective short datasets are being captured that include the essential details of the transplant programme. The fast fact data includes the number of transplant done yearly, the sex ratio and type of transplant. So far thirteen major institutional data has been entered in the registry. In the second phase of the registry, over twenty fields are likely to be captured and all member institutions would be encouraged to enter the data prospectively. In the third phase data would be derived with ongoing audit features.. The society and its members have supported the formation of the registry and are enthusiastic about its potential.

  18. PPAR-γ overexpression selectively suppresses insulin secretory capacity in isolated pancreatic islets through induction of UCP-2 protein

    International Nuclear Information System (INIS)

    Ito, Eisuke; Ozawa, Sachihiko; Takahashi, Kazuto; Tanaka, Toshiaki; Katsuta, Hidenori; Yamaguchi, Shinya; Maruyama, Masahiro; Takizawa, Makoto; Katahira, Hiroshi; Yoshimoto, Katsuhiko; Nagamatsu, Shinya; Ishida, Hitoshi

    2004-01-01

    Peroxisome proliferator-activated receptor-γ (PPAR-γ) regulates several cellular functions, but its physiological role in pancreatic islet cells remains to be investigated. In this study, we confirmed the presence of PPAR-γ in rat isolated islets and examined its role on insulin and glucagon secretion by using PPAR-γ-overexpressed islets. PPAR-γ overexpression significantly suppressed insulin secretion induced by stimulatory concentration of glucose (p < 0.05). In addition, insulin secretion evoked by high potassium depolarization also was significantly decreased from PPAR-γ-overexpressed islets (p < 0.05). On the other hand, no significant change in glucagon release was observed after high potassium depolarization between PPAR-γ-overexpressed and control islets. Insulin and glucagon content in islets was not statistically different between the two groups. In addition, the expression of uncoupling protein-2 (UCP-2) was found to be induced in PPAR-γ-overexpressed islets. This result clearly indicates that the deteriorative effect of PPAR-γ overexpression on the secretory machinery is selective for pancreatic β-cells. And it is possible that its site of action can be located in the energy-consuming exocytotic process of insulin secretory granules, and that the reduction of ATP production through increased UCP-2 reduces insulin exocytosis

  19. 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......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 h......RNA was up-regulated 3- to 4-fold in neonatal rat islets of Langerhans after 48-h culture with hGH, as found also with bovine GH or ovine PRL. During the development of pancreas from embryonic day 12 (E12) to postnatal day 4, we observed a 2-fold increase in Pref-1 mRNA on E17 and a 5-fold increase at birth...

  20. 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.

  1. Ultrastructural studies of time-course and cellular specificity of interleukin-1 mediated islet cytotoxicity

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Egeberg, J; Nerup, J

    1987-01-01

    of incubation and examined by electron microscopy in a blinded fashion. Already after 30 min, accumulation of opaque intracytoplasmic bodies without apparent surrounding membranes, and autophagic vacuoles were seen in about 20% of the beta cells examined in rat islets exposed to interleukin-1. After 16 h...

  2. Beta Cell Hubs Dictate Pancreatic Islet Responses to Glucose.

    Science.gov (United States)

    Johnston, Natalie R; Mitchell, Ryan K; Haythorne, Elizabeth; Pessoa, Maria Paiva; Semplici, Francesca; Ferrer, Jorge; Piemonti, Lorenzo; Marchetti, Piero; Bugliani, Marco; Bosco, Domenico; Berishvili, Ekaterine; Duncanson, Philip; Watkinson, Michael; Broichhagen, Johannes; Trauner, Dirk; Rutter, Guy A; Hodson, David J

    2016-09-13

    The arrangement of β cells within islets of Langerhans is critical for insulin release through the generation of rhythmic activity. A privileged role for individual β cells in orchestrating these responses has long been suspected, but not directly demonstrated. We show here that the β cell population in situ is operationally heterogeneous. Mapping of islet functional architecture revealed the presence of hub cells with pacemaker properties, which remain stable over recording periods of 2 to 3 hr. Using a dual optogenetic/photopharmacological strategy, silencing of hubs abolished coordinated islet responses to glucose, whereas specific stimulation restored communication patterns. Hubs were metabolically adapted and targeted by both pro-inflammatory and glucolipotoxic insults to induce widespread β cell dysfunction. Thus, the islet is wired by hubs, whose failure may contribute to type 2 diabetes mellitus. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  3. Pre-Microporation Improves Outcome of Pancreatic Islet Labelling for Optical and F-19 MR Imaging

    Czech Academy of Sciences Publication Activity Database

    Herynek, V.; Gálisová, A.; Srinivas, M.; van Dinther, E.A.W.; Kosinová, E.; Růžička, Jiří; Jirátová, K.; Kříž, J.; Jirák, D.

    2017-01-01

    Roč. 19, jun (2017), s. 6 ISSN 1480-9222 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : pancreatic islets * cell labelling * microporation Subject RIV: FP - Other Medical Disciplines Impact factor: 2.042, year: 2016

  4. Characterization of a pancreatic islet cell tumor in a polar bear (Ursus maritimus).

    Science.gov (United States)

    Fortin, Jessica S; Benoit-Biancamano, Marie-Odile

    2014-01-01

    Herein, we report a 25-year-old male polar bear suffering from a pancreatic islet cell tumor. The aim of this report is to present a case of this rare tumor in a captive polar bear. The implication of potential risk factors such as high carbohydrate diet or the presence of amyloid fibril deposits was assessed. Necropsy examination revealed several other changes, including nodules observed in the liver, spleen, pancreas, intestine, and thyroid glands that were submitted for histopathologic analysis. Interestingly, the multiple neoplastic nodules were unrelated and included a pancreatic islet cell tumor. Immunohistochemistry of the pancreas confirmed the presence of insulin and islet amyloid polypeptide (IAPP) within the pancreatic islet cells. The IAPP gene was extracted from the paraffin-embedded liver tissue and sequenced. IAPP cDNA from the polar bear exhibits some differences as compared to the sequence published for several other species. Different factors responsible for neoplasms in bears such as diet, infectious agents, and industrial chemical exposure are reviewed. This case report raised several issues that further studies may address by evaluating the prevalence of cancers in captive or wild animals. © 2014 Wiley Periodicals, Inc.

  5. Association between macrophage activation and function of micro-encapsulated rat islets

    NARCIS (Netherlands)

    de Vos, P; Smedema, I.; van Goor, H; Moes, H; van Zanten, J; Netters, S; de Leij, LFM; de Haan, Bart; de Haan, Aalzen

    Aims/hypothesis. Survival of microencapsulated islet grafts is limited, even when inflammatory reactions against the capsules are restricted to a small portion of less than 10%. Methods. This study investigates both in vivo in rat recipients and in vitro whether cellular overgrowth on this minority

  6. 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...

  7. Pilot application of sterile insect technique for the oriental fruit fly, Bactrocera Philippinensis, in Naoway islet

    International Nuclear Information System (INIS)

    Manoto, E.C.; Resilva, S.S.; Obra, G.B.; Reyes, M.R.; Golez, H.G.; Covacha, S.A.; Bignayan, H.G.; Zamora, N.F.; Gaitan, E.D.

    1996-01-01

    The sterile insect technique for the Oriental fruit fly was pilot tested in Naoway, a 12-ha islet about 1.5 km. southeast of Guimaras island. The Oriental fruit fly population (male) in the islet was first estimated at 3,432 using the mark-release-recapture experiments. From August to October 1995, six releases of sterile fruit flies (male and female) at biweekly intervals were conducted in the islet. Except for the 7 wild fruit flies collected by a trap 10 days after the first release, not a single fly was collected from the pilot site thereafter. Furthermore, field collections of infested fruits yield only 6 pupae on the first and zero on the subsequent collections. The results suggested that SIT proved successful in Naoway islet. For Guimaras, an island-wide implementation of SIT could be undertaken after reducing the wild male fruit fly population by field sanitation and the male annihilation method in order to overflood the wild population with sterile fruit flies. (Author)

  8. Early differences in islets from prediabetic NOD mice: combined microarray and proteomic analysis

    DEFF Research Database (Denmark)

    Crèvecoeur, Inne; Gudmundsdottir, Valborg; Vig, Saurabh

    2017-01-01

    Type 1 diabetes is an endocrine disease where a long preclinical phase, characterised by immune cell infiltration in the islets of Langerhans, precedes elevated blood glucose levels and disease onset. Although several studies have investigated the role of the immune system in this process of insu...

  9. Differential expression of glutamic acid decarboxylase in rat and human islets

    DEFF Research Database (Denmark)

    Petersen, J S; Russel, S; Marshall, M O

    1993-01-01

    The GABA synthesizing enzyme GAD is a prominent islet cell autoantigen in type I diabetes. The two forms of GAD (GAD64 and GAD67) are encoded by different genes in both rats and humans. By in situ hybridization analysis of rat and human pancreases, expression of both genes was detected in rat isl...

  10. 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...

  11. 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.

  12. Improved biocompatibility but limited graft survival after purification of alginate for microencapsulation of pancreatic islets

    NARCIS (Netherlands)

    DeVos, P; DeHaan, BJ; Wolters, GHJ; Strubbe, JH; VanSchilfgaarde, R; van Schilfgaarde, P.

    Graft failure of alginate-polylysine microencapsulated islets is often interpreted as the consequence of a non-specific foreign body reaction against the microcapsules, initiated by impurities present in crude alginate. The aim of the present study was to investigate if purification of the alginate

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

    Directory of Open Access Journals (Sweden)

    Daniel J Moore

    2010-10-01

    Full Text Available Insulin-dependent Type 1 diabetes (T1D is a devastating autoimmune disease that destroys beta cells within the pancreatic islets and afflicts over 10 million people worldwide. These patients face life-long risks for blindness, cardiovascular and renal diseases, and complications of insulin treatment. New therapies that protect islets from autoimmune destruction and allow continuing insulin production are needed. Increasing evidence regarding the pathomechanism of T1D indicates that islets are destroyed by the relentless attack by autoreactive immune cells evolving from an aberrant action of the innate, in addition to adaptive, immune system that produces islet-toxic cytokines, chemokines, and other effectors of islet inflammation. We tested the hypothesis that targeti