Use of trypsin for isolation of islets of Langerhans in the rat.

A new technique for pancreatic islet isolation, based on trypsin administered into the pancreatic duct system and a reduced amount of collagenase for digestion of the removed and chopped pancreatic tissue, yielded viable islets as judged by the metabolic response of 27 inbred, streptozotocin-diabetic rats after intraportal transplantation of the islets: all recipients of greater than 240 islets normalized their blood glucose, plasma insulin, urine volume and urinary glucose. The number of islets isolated was the same as with the conventional collagenase technique.     

Pancreatic islet isografts, allografts, and xenografts: comparison of morphology and function.

Neonatal rat pancreatic islets were transplanted intraperitoneally into adult streptozotocin-diabetic rats and mice. Isologous pancreatic islet recipients (12 of 12) showed consistent and permanent reconstitution of normoglycemia and normal weight gain as well as readjustment to normal of intake of water, urine volume, and glucose excretion for greater than 10 months when compared to age-matched normal (ten) and diabetic (20) controls. Revascularized isologous islet grafts were found to be adherent to both visceral and parietal peritoneum. Pancreatic islet allografts (ten) and allografts and xenografts did not appear to differ markedly; both were characterized by dense round-cell infiltration within 5 days after transplantation.     

异体大鼠骨髓单个核细胞胰岛细胞移植治疗糖尿病

目的 观察异体骨髓单个核细胞和胰岛细胞通过肝脏和静脉途径移植后对糖尿病大鼠的治疗作用.方法 密度梯度离心法分离胰岛细胞,淋巴细胞分离液分离骨髓单个核细胞,28只糖尿病大鼠模型随机分为A、B、C、D组,A组在肝脏被膜下多点注射1000个胰岛细胞,B组在体外将1000个胰岛细胞和1×107个骨髓单个核细胞混合后在肝脏被膜下多点注射,C组通过尾静脉注射1000个胰岛细胞,D组在体外将1000个胰岛细胞和1×107个骨髓单个核细胞混合后通过尾静脉注射,移植后于不同时间点尾静脉测定随机血糖,比较不同细胞组合和移植途径之间对糖尿病的治疗作用.结果 A、B组血糖于术后3 d内开始下降,A组血糖可降至正常水平(7.98±2.28)mmol/L,血糖维持正常水平(3.71±0.95)d,B组降至(7.72±1. 75)mmol/L可维持(4.86±1.06)d,静脉移植组血糖于术后4 d内降至正常(7.35±1.40)mmol/L,可维持(7.85±1.46)d,D组静脉注射胰岛于4 d起效(7.00±0.83)mmol/L,血糖可降至正常水平可维持(14.10±1.21)d,各组间血糖随时间变化的趋势及维持正常水平的时间具有统计学意义(P＜0.05).结论 骨髓单个核细胞和胰岛混合细胞通过尾静脉移植对大鼠血糖维持正常时间最长,血糖控制水平最理想.     

Transplantation of fetal rat islets into the cerebral ventricles of alloxan-diabetic rats. Amelioration of diabetes by syngeneic but not allogeneic islets

Syngeneic fetal rat islets were isolated and transplanted into alloxan-diabetic inbred male Lewis rats. The effect of transplantation of islets into the cerebral ventricles on the diabetic state of the recipients was compared with that of the conventional transplantation of islets homeotypically into the liver via the portal vein. Fourteen of fourteen rats surviving after stereotaxic implantation of islets into the ventricles returned to normoglycemia; normoglycemia has been maintained for up to 34 wk. Glucose tolerance tests revealed an improved, although not completely normalized, pattern. Histologic examination of the brains of these recipients revealed clusters of intact islets in the ventricle. These data provided a physiologic basis for further investigation of the immunologically privileged nature of the intraventricular space as a site for implantation of allogeneic pancreatic islets. Islets from Wistar-Furth rats (major histocompatibility difference) or Fischer 344 rats (minor histocompatibility difference) were transplanted into the ventricles of alloxan-diabetic Lewis rats. There were only small and unsustained changes in body weight and blood and urine glucose of any of the rats receiving the allogeneic islets. Histologic examination of the ventricles of these rats 3 wk after transplantation revealed only glial scar tissue. These data suggest that the cerebral ventricles cannot serve as a privileged site for islet transplantation, at least using the type of islet preparation employed in these experiments.     

同种异体胰岛及胰腺干细胞来源的胰岛样结构序贯移植治疗糖尿病

目的 观察同种异体大鼠胰岛及胰腺干细胞来源的胰岛样结构序贯移植在糖尿病治疗中的作用.方法 分离胰腺组织获得胰岛及胰腺导管上皮细胞,将具有干细胞潜能的胰腺导管上皮细胞在体外培养27d.将新鲜分离的胰岛(200±50)个及诱导分化2周的胰腺干细胞来源的胰岛样结构(2×106)个序贯移植到糖尿病大鼠的肾被膜下观察大鼠的血糖及生存情况.结果 将胰岛及胰腺干细胞来源的胰岛样结构序贯移植到同一糖尿病大鼠3周后血糖仍在5 mmol/L水平,对照组血糖无明显下降.结论 胰腺干细胞可诱导分化为分泌胰岛素的胰岛样结构,胰岛及胰腺干细胞来源的胰岛样结构序贯移植对大鼠糖尿病有治疗作用.     

Allotransplantation of rat islets into the cisterna magna of streptozotocin-induced diabetic rats.

Islets were isolated from the pancreata of Sprague-Dawley rats and transplanted into streptozotocin-induced diabetic outbred Wistar rats. The effect of transplantation of islets into the cisterna magna on the diabetic state of the recipients was compared with that of the conventional transplantation of islets into liver via the portal vein. After successful intraportal (IP) transplantation, rejection took place between days 7 and 15 in all diabetic recipients. All of the eleven rats surviving after stereotaxic implantation of islets into the cisterna magna returned to normoglycemia within 7 days after transplantation. Nine of the recipients with intra-cisterna magna (IM) islet allografts were still normoglycemic at 210 days after transplantation. The glucose disappearance rate of the IM transplant rats was slower than that of the IP transplant rats, and blood glucose returned to the normal basal level within 5 hr following glucose administration. Although the insulin levels were almost undetectable in cerebrospinal fluid before IM transplantation, the insulin levels were markedly increased after IM transplantation and twice as great in CSF than blood. Thus, these findings indicate that the cisterna magna can serve as an immunologically privileged site for implantation of allogeneic pancreatic islets, and islets in CSF can regulate and maintain normal glucose homeostasis via secretion of insulin across the blood-brain barrier.     

The use of iodixanol for the purification of rat pancreatic islets

Transplantation of pancreatic islets is a promising therapeutic treatment for type 1 diabetes mellitus. For clinical and experimental transplantation, a large number of pure pancreatic islets are required for transplantation. Thus, the improvement of islet isolation and purification techniques are crucial. In this context, iodixanol-based solution, successfully used for the purification of porcine islets, seems to be a possible alternative to Ficoll for purification of islets. The aim of this study was to test the efficacy of iodixanol compared with Ficoll density gradients for the purification of rat pancreatic islets. Twelve Wistar rats were used for isolation and purification of pancreatic islets. Pancreata were digested with Liberase R1 and islets purified by two gradients: Ficoll or iodixanol gradient. The number and the purity of the pancreatic islets were assessed. To analyze the response of isolated pancreatic islet to glucose challenge, in vitro experiments were performed by measuring the insulin concentration in the Supernatant. The results demonstrated that the iodixanol gradient provided a higher purity of pancreatic islets compared to the Ficoll gradient. In addition, the rat islet yield by iodixanol gradient was significantly higher compared to a Ficoll gradient (751 +/- 16 versus 464 +/- 19 pancreatic islets, respectively; P < .001). The viability of pancreatic islets isolated by an iodixanol gradient was confirmed by high glucose challenge, with more than twofold higher increase in insulin secretion. The present study demonstrated that iodixanol density gradient overcomes Ficoll density gradient, providing a greater number of pure and functional rat pancreatic islets.     

Dynamics of glycemic normalization following transplantation of incremental islet masses in streptozotocin-diabetic rats.

We examined the dynamics of glycemic normalization following intraportal infusion of an incremental number of islets of Langerhans in male Wistar-Furth rats. Non-fasted plasma glucose, 24-hr urine volume, and body weight were determined weekly during three weeks of streptozotocin-induced diabetes and for 5 weeks following transplantation of 250-3000 freshly isolated islets. At one week following transplantation, urine volume was inversely proportional to the mass of islets transplanted, but by 5 weeks posttransplantation urine volume was near-normal except in rats receiving only 250 islets. On the basis of the mean data, the nonfasted plasma glucose fell linearly at a rate of 66 mg/dl per week in rats receiving 500-1000 islets, with normoglycemia (147 +/- 9 mg/dl) being obtained 5 weeks posttransplantation. Examination of the individual time courses for nonfasted plasma glucose revealed a different pattern of glycemic normalization, which consisted of sustained hyperglycemia followed by a rapid fall in the plasma glucose level. During the week prior to normalization glucose fell at a rate of 170 mg/dl per week and normoglycemia was obtained from 1 to 5 weeks following transplantation. Examination of the frequency distribution of nonfasted glucose levels suggested a threshold of 300 mg/dl for glycemic normalization. We conclude that the dynamics of glycemic normalization following transplantation of a suboptimal islet mass include sustained hyperglycemia of variable duration, followed by a rapid fall in the nonfasted plasma glucose level. The contributions of changes in insulin secretion and insulin action underlying this dynamic behavior remain to be determined.     

Long‐term engraftment and function of transplanted pancreatic islets in vascularized segments of small intestine

This study evaluated the potential of vascularized small intestinal segments for pancreatic islet transplantation. Islets isolated from Lewis rats were transplanted into diabetic syngeneic recipients. Segments of small intestine were prepared by denudation of the mucosal layer prior to implantation of pancreatic islets into the segments. Animal groups were established to determine engraftment, survival and function of islets transplanted into either intestinal segments or portal vein over up to 60 days. We found transplantation of functionally intact pancreatic islets into small intestinal segments was well tolerated. Transplanted islets were rapidly engrafted in intestinal segments as demonstrated vascularization and expression of insulin and glucagon throughout the 60‐day duration of the studies. Transplantation of islets restored euglycemia in diabetic rats, which was similar to animals receiving islets intraportally. Moreover, animals treated with islet transplants showed normal responses to glucose challenges. Removal of graft‐bearing intestinal segments led to recurrence of hyperglycemia indicating that transplanted islets were responsible for improved outcomes. Therefore, we concluded that vascularized intestinal segments supported reorganization, survival and function of transplanted islets with therapeutic efficacy in streptozotocin‐treated diabetic rats. The approach described here will be appropriate for studying islet biogenesis, reorganization and function, including for cell therapy applications.     

Influence of the numbers of islets on the models of rat syngeneic-islet and allogeneic-islet transplantations

One of the main barriers to widespread application of islet transplantation is the limited availability of human pancreatic islets. The reduction of graft islet mass for transplantation to a recipient is one of the strategies in islet transplantation. However, transplantation of only a small number of islets may result in primary nonfunction. To optimize the sites and numbers of islets for transplantation, we analyzed these factors using pancreatic islets from Lewis or F344 rats transplanted into rats rendered diabetic by streptozotocin (50 mg/kg IV) and confirmed as such prior to transplantation (>300 mg/dL blood glucose). Approximately 500 to 1500 islets were injected via the portal vein or under the renal capsule into the diabetic F344 rats. The blood glucose level of all animals bearing 1500 syngeneic or allogeneic islets transplanted to the liver or under the kidney capsule exhibited restored normoglycemia (<200 mg/dL) at 1 day after transplantation. Graft function deteriorated after only 3 days in three animals (5.8%). The loss of graft function after 3 days occurred in 10 of 28 rats transplanted with 1000 to 1200 syngeneic islets, 4 of 19 rats transplanted with 800 to 900 syngeneic islets, and 7 of 17 rats transplanted with 500 to 600 syngeneic islets. There was no significant difference in the loss of graft function between the sites of transplantation via portal vein or under the kidney capsule. In conclusion, higher frequencies of primary nonfunction occurred with less than 1500 islets transplanted. They were independent of the sites in the rat-islet transplantation model.     

An Isolated Venous Sac as a Novel Site for Cell Therapy in Diabetes Mellitus

BACKGROUND: Transplanting pancreatic islets is of significant interest for type 1 diabetes mellitus. After intraportal injection of islets, inferior engraftment and eventual loss of transplanted islets constitute major limitations. Therefore, alternative approaches will be helpful. Here, we evaluated in animals whether an isolated venous sac would support survival of transplanted islets, along with correction of hyperglycemia. METHODS: Pancreatic islets isolated from adult Lewis rats were transplanted either into an isolated venous sac made from lumbar vein or into the portal vein of syngeneic rats. The integrity and vascular organization of the venous sac was determined by studies of the local microcirculation. The engraftment, survival, and function of transplanted islets were analyzed by histology, including endocrine function in situ and by glycemic control in rats with streptozotocin-induced diabetes. RESULTS: Transplanted islets showed normal morphology with insulin expression in isolated venous sac during the long term. Transplanted islets received blood supply from vasa vasorum and had access to drainage through venous tributaries in the venous sac. This resulted in restoration of euglycemia in diabetic rats. Removal of islet graft-bearing venous sac in diabetic rats led to recurrence of hyperglycemia. By contrast, euglycemia was not restored in rats treated by intraportal transplantation of islets. CONCLUSIONS: We demonstrated that pancreatic islets successfully engrafted and functioned in the isolated venous sac with ability to restore euglycemia in diabetic rats. Therefore, the isolated venous sac offers a new site for transplantation of pancreatic islets. This would be clinically beneficial as an alternative to intrahepatic islet transplantation.     

Viability of the islets of Langerhans after warm ischemia as judged by isologous transplantation.

The influence of warm ischemia on pancreatic islet viability was studied by means of 63 isologous transplantations in adult AGUS rats. The pancreases were harvested 0, 20 and 40 min after circulatory arrest. The islets were isolated with collagenase and transplanted intra-portally in known numbers into streptozotocin-diabetic recipients. The islet-dose-metabolic-response relationships in three groups of recipients were compared. No significant difference was found in the quantitative yield. The smallest number of islets which reversed diabetes increased by 25% after a period of warm ischemia regardless of its duration.     

Alpha-melanocyte stimulating hormone preserves islet graft survival through down-regulation of Toll-like receptors

The induction of Toll-like receptors (TLRs) in β cells is involved in β-cell death and graft rejection after transplantation. This study investigated the ability of alpha-melanocyte stimulating hormone (α-MSH) to protect pancreatic islets and improve graft survival through regulation of TLRs. To test the effect of α-MSH on TLR regulation, we first isolated pancreatic islets from rats pretreated with/without α-MSH and assayed inflammatory cytokines and insulin release, and measured the expression of TLRs. Pancreatic islets were transplanted into the kidney capsule of a diabetes mellitus (DM) mouse with and without prior injection of α-MSH. The blood glucose levels were measured and TLR4 expression in transplanted kidney tissue was assessed. Islet morphology, including size and total mass, was improved in the α-MSH group compared to the control group. The expression of TLRs as well as nitric oxide and monocyte chemoattractant protein 1 production were decreased in islets isolated from α-MSH-treated rats. In DM mice, the normoglycemic ratio was higher in the α-MSH-treated group than in the sham group. Moreover, the high levels of TLR4 expression observed in DM kidney tissue were significantly decreased in islet-transplanted tissue with α-MSH. This study showed that α-MSH protects pancreatic islets from cell death and dysfunction through downregulation of TLRs. In conclusion, α-MSH could contribute to improved islet graft survival and function in pancreatic islet transplantation.     

Hyperoxia improves the survival of intraportally transplanted syngeneic pancreatic islets

BACKGROUND: Hypoxia in the portal vein may compromise the survival of intraportally transplanted pancreatic islets. We therefore examined the effect of inspired oxygen on the outcome of islet transplantation. METHODS: Blood glucose concentrations, glucose tolerance, and the size and number of surviving islets were measured in diabetic rats housed for 48 hr under hyperoxic (100% O(2)), hypoxic (11% O(2)), or normoxic (21%O(2)) conditions after intraportal transplantation of 350, 500, 700, or 1,000 syngeneic islets. RESULTS: In normoxic diabetic rats, the smallest graft size to consistently restore normoglycemia was 1,000 islets. A graft size of 700 islets was effective in only three of nine animals, whereas 500 islets were ineffective in all eight animals undergoing transplantation. In contrast, in hyperoxically housed rats, graft sizes of 700 or 500 islets restored normoglycemia in eight of nine or five of eight animals, respectively. In those animals that became normoglycemic, the glucose tolerance of the hyperoxically treated rats receiving 700 islets was almost identical to that of normoxically housed animals receiving 1,000 islets. The average size of the islets 6 weeks after transplantation was the same in livers of hyperoxic and control rats. However, the total islet area and number of islets engrafted in hyperoxic rats was significantly increased when compared with livers from normoxic animals receiving the same graft size, so the area in hyperoxic rats receiving 700 islets was not significantly different from normoxic recipients of 1,000 islets. CONCLUSIONS: Hyperoxia posttransplantation increases the number of islets that survive the engraftment process and allows normalization of plasma glucose levels with a smaller number of transplanted islets.     

三种不同部位移植胰岛细胞治疗糖尿病

目的 对比通过肝脏、静脉、胰腺三种途径移植胰岛细胞对糖尿病大鼠的治疗作用.方法 24只糖尿病大鼠模型随机分为A、B、C组,A组在肝脏被膜下多点移植1000个胰岛细胞,B组通过尾静脉移植1000个胰岛细胞,C组在胰腺被膜下移植1000个胰岛细胞,于不同时间点测定大鼠随机血糖,对比大鼠血糖变化趋势及维持正常的时间.结果 A组大鼠血精于术后3 d内开始下降,血糖可降至正常水平(7.98±2.28)mmol/L,血糖维持正常水平(3.71±0.95)d,B组移植后24 h 血糖降至正常水平(7.35±1.40)mmol/L,可维持(7.85±1.46)d,C组移植后24 h血糖降至正常水平(7.06±2.11)mmol/L,可维持(24.90±2.60)d,不同部位移植对大鼠血糖水平变化的影响不同,差异有统计学意义(P＜0.05).结论 在胰腺被膜下移植胰岛细胞血糖维持正常时间最长,是一个较理想的移植部位.

Abstract：

Objective To study the curative effectiveness of pancreatic islets transplantation through the liver, tail vein and pancreas. Methods Twenty-four diabetic rats were randomly divided into groups 1,2, 3. The rats in group Ⅰ were transplanted with 1000 pancreatic islets beneath the liver capsule,those in group 2 with 1000 pancreatic islets through tail vein, and those in group 3 with 1000 pancreatic islets beneath the pancreas capsule. Plasma glucose levels at different time points were determined and compared. Results In group 1, plasma glucose levels were reduced at the 3rd day post-transplantation,reached the normal level (7.98 ±2. 28) mmol/L and maintain (3.71 ±0. 95) days. Group 2 start to activate after 24 h. Plasma glucose level reach to (7.35 ± 1.40) mmol/L and maintain (7.85 ± 1.46) days.Group 3 start to activate after 24 h. Plasma glucose level reach to ( 7.06 ± 2. 11 ) mmol/L and maintain (24. 90 ± 2. 60 ) days. There is statistical significance in plasma glucose level and maintain normal time after transplantation pancreatic islet in different sites ( P ＜ 0. 05 ). Conclusion Transplantation pancreatic islets beneath the pancreas capsule maintain plasma glucose for the longest time. The pancreas is a ideal transplantation site.     

Tissue culture preservation and intramuscular transplantation of pancreatic islets.

Pancreatic tissue from neonatal rats was cultured for 6 days and then transplanted into isologous animals made diabetic with streptozotocin. The cultured pancreatic tissue was implanted either into the peritoneal cavity or into muscle pockets and showed survival by functional and morphological studies for longer than 40 weeks. Pancreatic tissue from a patient subjected to subtotal pancreatectomy for chronic pancreatitis was maintained in culture for 7 days, with evidence for insulin release into medium, sterility, and histological viability of islets. Autotransplantation of this tissue into muscle pockets of the forearm was tolerated well. Glucose tolerance improved following transplantation, but evidence for function of the graft (insulin, C-peptide) remains inconclusive, 4 months after transplantation.     

Insulin-releasing activity and successful transplantation of pancreatic islets preserved by tissue culture.

Preserving pancreatic islets for 7 days by a making use of the organ culture, we studied the insulin-releasing activity at the time of administration of glucose and various digestive tract hormones for the purpose of clarifying the function of preserved pancreatic islets. Furthermore, we transplanted pancreatic islets preserved for 3 to 5 days into the portal vein of rats with streptozotocin-induced diabetes and reached the following conclusions: (1). The islets of Langerhans of the pancreas responded well to glucose up to the seventh day of preservation and showed patterns similar to those of fresh pancreatic islets with respect to both the dose response and the time response. (2). Preserved pancreatic islets of the pancreas had insulin-releasing activity almost equal to that of fresh pancreatic islets against stimulation by glucagon, tolbutamide, and various digestive tract hormones. (3). Rats with streptozotocin-induced diabetes showed a marked improvement in blood glucose and urine glucose following transplantation of preserved pancreatic islets into the portal vein, and this effectiveness persisted for 6 to 8 weeks.     

Modified subcutaneous tissue with neovascularization is useful as the site for pancreatic islet transplantation

The success rate of subcutaneous transplantation of pancreatic islets has been extremely low. Insufficient oxygen supply to the grafted islets is one possible major obstacle to the preservation of graft function. This study attempted to use basic fibroblast growth factor (bFGF) in subcutaneous transplantation to induce neovascularization and a sufficient blood flow around the space formed for grafted islets in the subcutaneous tissues. A bFGF-releasing device was designed enclosing bFGF in a polyethylene terephthalate mesh bag coated with polyvinylalcohol hydrogel. In the vascularized group (n = 5), two bFGF-releasing devices were implanted bilaterally into the subcutaneous tissue of the back of streptozotocin-induced diabetic Lewis rats. One week after implantation, isolated rat islets (5000) were syngeneically transplanted subcutaneously after the removal of the devices. In the control group (n = 5), no devices were implanted and the same number of rat islets was transplanted directly. One week after the implantation of the devices into the test animals, a thick, well-vascularized capsule was observed in the subcutaneous site. All vascularized recipient rats showed significant decreases in nonfasting blood glucose and maintained normoglycemia for more than 1 month after islet transplantation. However, in the control group, all rats failed to achieve normoglycemia after transplantation. This study provides evidence that the subcutaneous tissue is a promising site for pancreatic islet transplantation, offering convincing advantages in acceptability for diabetic recipients. Establishment of this subcutaneous islet transplantation technique will afford some new perspectives on successful clinical islet transplantation.     

Revascularization and function of pancreatic islet isografts in diabetic rats following transplantation

In pancreatic islet transplantation, revascularization is crucial for the graft's survival and function. In this study, the endothelium of isolated islets and revascularization and function of islet isografts in diabetic rat were investigated. Islets were isolated from Lewis rats by collagenase digestion method and were examined using immunohistochemistry (CD31 stain) on days 0, 1, 3, and 7 after isolation. The number of CD31-positive cells in these isolated islets was counted (mean +/- SD %). Isografts (freshly isolated islets: group A, and islets cultured for 7 days: group B) transplanted in the renal subcapsule of streptozotocin-induced diabetic Lewis rats were examined using immunohistochemistry (CD31 stain) on days 3, 5, and 7 after transplantation. Intravenous glucose tolerance tests (IVGTT) were performed on days 3 and 7 after transplantation. The number of CD31-positive cells in the isolated islets on days 0, 1, 3, and 7 after isolation were: 17.3 +/- 4.1%, 8.2 +/- 0.7%, 2.1 +/- 0.8%, and 0.8 +/- 0.5%, respectively (p < 0.05). On day 5 after transplantation, CD31-positive cells were not detected in group A and B grafts, but were detected in both groups in periphery of the islets. On day 7, CD31-positive microvessels were present throughout the entire graft. IVGTT values in groups A and B on days 3 and 7 after transplantation did not show significant differences. In renal subcapsular isografts in diabetic rats, revascularization into islet grafts occurs from the surrounding host tissue 5 days after transplantation, but has no influence on the response to glucose during this period.     

The use of non-heart-beating donors for isolated pancreatic islet transplantation

Recent improvements in isolated islet transplantation indicate that this therapy may ultimately prove applicable to patients with type I diabetes. An obstacle preventing widespread application of islet transplantation is an insufficient supply of cadaveric pancreata. Non-heart-beating donors (NHBDs) are generally not deemed suitable for whole-organ pancreas donation and could provide a significant source of pancreata for islet transplantation. Isolated pancreatic islets prepared from 10 NHBDs were compared with those procured from 10 brain-dead donors (BDDs). The success of the isolation for the two groups was analyzed for preparation purity, quality, and recovered islet mass. The function of NHBD and BDD islets was evaluated using in vitro and in vivo assays. On the basis of the results of this analysis, an NHBD isolated islet allograft was performed in a type I diabetic. The recovery of islets from NHBDs was comparable to that of control BDDs. In vitro assessment of NHBD islet function revealed function-equivalent BDD islets, and NHBD islets transplanted to non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice efficiently reversed diabetes. Transplantation of 446,320 islet equivalents (IEq) (8,500 IEq/kg of recipient body weight) from a single NHBD successfully reversed the diabetes of a type I diabetic recipient. Normally functioning pancreatic islets can be isolated successfully from NHBDs. A single donor transplant from an NHBD resulted in a state of stable insulin independence in a type I diabetic recipient. These results indicate that NHBDs may provide an as yet untapped source of pancreatic tissue for preparation of isolated islets for clinical transplantation.