Viable Purified Islets of Langerhans From Collagenase-Perfused Human Pancreas

Warnock, Garth L.; Ellis, Dwayne; Cattral, Mark S.; D, Untch; Kneteman, Norman M.; Rajotte, Ray V.

doi:10.2337/diab.38.1.s136

Cited by 23 publications

(9 citation statements)

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“…1A illustrates a typical yield histogram from a rat islet preparation. The large islets account for 73% of the total islet equivalencies, and the small islets make up the remaining 27% (n ϭ 43 rats), which is consistent with previous publications (23). Note the bimodal distribution of the islets, with a peak at 75-100 m for the small islets and another smaller peak at Figure 1B shows the size histogram after density gradient separation of the small and large rat islets.…”

Section: Yieldsupporting

confidence: 73%

Small rat islets are superior to large islets in in vitro function and in transplantation outcomes

Macgregor¹,

Williams²,

Tong³

et al. 2006

American Journal of Physiology-Endocrinology and Metabolism

155

162

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Barriers to the use of islet transplantation as a practical treatment for diabetes include the limited number of available donor pancreata. This project was designed to determine whether the size of the islet could influence the success rate of islet transplantations in rats. Islets from adult rats were divided into two groups containing small (diameter Ͻ125 m) or large (diameter Ͼ150 m) islets. An average pancreas yielded three times more small islets than large. Smaller islets were ϳ20% more viable, with large islets containing a scattered pattern of necrotic and apoptotic cells or central core cell death. Small islets in culture consumed twice as much oxygen as large islets when normalized for the same islet equivalents. In static incubation, small islets released three times more insulin under basal conditions than did large islets. During exposure to high glucose conditions, the small islets released four times more insulin than the same islet equivalencies of large islets, and five times more insulin was released by the small islets in response to glucose and depolarization with K ϩ . Most importantly, the small islets were far superior to large islets when transplanted into diabetic animals. When marginal islet equivalencies were used for renal subcapsular transplantation, large islets failed to produce euglycemia in any recipient rats, whereas small islets were successful 80% of the time. The results indicate that small islets are superior to large islets in in vitro testing and for transplantation into the kidney capsule of diabetic rats. islet transplant; insulin secretion; viability THE RISE IN CASES OF DIABETES MELLITUS in the United States has been called an epidemic. It is the third leading cause of death by disease and rivals heart disease and cancer as a major killer of United States citizens. For unexplained reasons the occurrence of type 1 diabetes is increasing worldwide, and the age of onset has decreased by 3-5 yr over the past decade so that many children now develop diabetes before entering school. The result is that more people with diabetes will spend a larger percentage of their life at risk for developing the chronic complications related to type 1 diabetes. Because the risk for development of most of the chronic complications associated with diabetes is related to glycemic control, significant attention is directed toward novel therapies, such as islet transplantation, to improve glycemic control.Islet transplants in humans were first attempted in the 1980s (7, 8). Initial success rates for human islet transplantation were disappointing, with only 5% of patients receiving transplants achieving partial function (19). Amid the failures were isolated success stories of individuals achieving prolonged reversal of their diabetes for a 1-to 2-yr period (19), which encouraged researchers to continue this approach for the treatment of diabetes. In 2000, islet transplantations were performed successfully on seven patients with diabetes by using a suppression regimen that omitted glucocorticoid...

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Section: Yieldsupporting

confidence: 73%

Small rat islets are superior to large islets in in vitro function and in transplantation outcomes

Macgregor¹,

Williams²,

Tong³

et al. 2006

American Journal of Physiology-Endocrinology and Metabolism

155

162

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“…Islets and tissue. Human, monkey, and newborn rat islets were isolated essentially as described previously (20)(21)(22). Sera and antibodies.…”

Section: Methodsmentioning

confidence: 99%

Recombinant Glutamic Acid Decarboxylase (Representing the Single Isoform Expressed in Human Islets) Detects IDDM-Associated 64,000-Mr Autoantibodies

et al. 1992

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GAD is an autoantigen in IDDM. Molecular cloning and specific antibodies allowed us to demonstrate that only the lower M r GAD64 isoform is expressed in human islets, in contrast to human brain, rat islets, and rat brain, all of which express both GAD64 and GAD67. Expression of the human islet GAD64 isoform in COS-7 and BHK cells resulted in an enzymatically active rGAD64, which is immunoreactive with diabetic sera comparable with that of the islet 64,000-Af r autoantigen. Immunoprecipitation analyses showed that 21/28 (75%) IDDM sera had rGAD64 antibodies compared with only 1/59 (1.7%) of the healthy control sera. In immunoblot analyses, an SMS serum-but only 1/10 randomly selected IDDM sera-recognized the blotted rGAD64 without relation to immunoprecipitation titers. In conclusion, only the GAD64 isoform is expressed in human islets, in contrast to rat islets, which also express the GAD67 isoform. The immunological properties of human rGAD64 are comparable with the native 64,000-M r islet autoantigen, allowing further studies of the immunopathogenesis of IDDM. Diabetes 41:1355-59, 1992

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“…The glands were then removed and transported to the Central Unit ofthe f-Cell Transplant (Medical Campus, Vrije Universiteit Brussel, Brussels, Belgium). At the Central Unit the glands were processed by ductal distension with collagenase, gentle dissociation, and Ficoll gradient purification of islets, as previously described (20). Aliquots of the purified suspension were examined by electron microscopy, which indicated < 10% dead cells in all preparations, and the presence of 6.6±2.3% exocrine cells (mean+SEM; n = 14).…”

Section: Methodsmentioning

confidence: 99%

Prolonged exposure of human pancreatic islets to high glucose concentrations in vitro impairs the beta-cell function.

Korbutt²,

1992

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The aim of the present study was to clarify whether prolonged in vitro exposure of human pancreatic islets to high glucose concentrations impairs the function of these cells. For this purpose, islets isolated from adult cadaveric organ donors were cultured for seven days in RPMI 1640 medium supplemented with 10% fetal calf serum and containing either 5.6, 11, or 28 mM glucose. There was no glucose-induced decrease in islet DNA content or signs of morphological damage. However, islets cultured at 11 or 28 mM glucose showed a 45 or 60% decrease in insulin content, as compared to islets cultured at 5.6 mM glucose. Moreover, when such islets were submitted to a 60-min stimulation with a low (1.7 mM) followed by a high (16.7 mM) concentration of glucose, the islets cultured at 5.6 mM glucose showed a higher insulin response to glucose than those of the two other groups. Islets cultured at the two higher glucose concentrations showed increased rates of insulin release in the presence of low glucose, and a failure to enhance further the release in response to an elevated glucose level. Islets cultured at 28 mM glucose showed an absolute decrease in insulin release after stimulation with 16.7 mM glucose, as compared to islets cultured at 5.6 mM glucose. The rates of glucose oxidation, proinsulin biosynthesis, and total protein biosynthesis were similar in islets cultured at 5.6 or 11 mM glucose, but they were decreased in islets cultured at 28 mM glucose. These combined results suggest that lasting exposure to high glucose concentrations impairs the function of human pancreatic islets. (J.

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Viable Purified Islets of Langerhans From Collagenase-Perfused Human Pancreas

Cited by 23 publications

References 0 publications

Small rat islets are superior to large islets in in vitro function and in transplantation outcomes

Small rat islets are superior to large islets in in vitro function and in transplantation outcomes

Recombinant Glutamic Acid Decarboxylase (Representing the Single Isoform Expressed in Human Islets) Detects IDDM-Associated 64,000-Mr Autoantibodies

Prolonged exposure of human pancreatic islets to high glucose concentrations in vitro impairs the beta-cell function.

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