Genetically modified human bone marrow derived mesenchymal stem cells for improving the outcome of human islet transplantation

The objective of this study was to determine the potential of human bone marrow derived mesenchymal stem cells (hBMSCs) as gene carriers for improving the outcome of human islet transplantation. hBMSCs were characterized for the expression of phenotypic markers and transduced with Adv-hVEGF-hIL-1Ra to overexpress human vascular endothelial growth factor (hVEGF) and human interleukin-1 receptor antagonist (hIL-1Ra). Human islets were co-cultured with hBMSCs overexpressing hVEGF and hIL-1Ra. Islet viability was determined by membrane fluorescent method and glucose stimulation test. Transduced hBMSCs and human islets were co-transplanted under the kidney capsule of NOD.Cg-Prkdc^scid Il2rg^tm1Wjl/SzJ (NSG) diabetic mice and blood glucose levels were measured over time to demonstrate the efficacy of genetically modified hBMSCs. At the end of study, immunofluorescent staining of kidney section bearing islets was performed for insulin and von Willebrand Factor (vWF). hBMSCs were positive for the expression of CD73, CD90, CD105, CD146 and Stro-1 surface markers as determined by flow cytometry. Transduction of hBMSCs with adenovirus did not affect their stemness and differentiation potential as confirmed by mRNA levels of stem cell markers and adipogenic differentiation of transduced hBMSCs. hBMSCs were efficiently transduced with Adv-hVEGF-hIL-1Ra to overexpress hVEGF and hIL-1Ra. Live dead cell staining and glucose stimulation test have shown that transduced hBMSCs improved the viability of islets against cytokine cocktail. Co-transplantation of human islets with genetically modified hBMSCs improved the glycemic control of diabetic NSG mice as determined by mean blood glucose levels and intraperitoneal glucose tolerance test. Immunofluorescent staining of kidney sections was positive for human insulin and vWF. In conclusion, our results have demonstrated that hBMSCs may be used as gene carriers and nursing cells to improve the outcome of islet transplantation.

Nitric oxide mediates early dysfunction of rat and mouse islets after transplantation

Evidence presented in this paper indicates that nitric oxide (NO), generated by a nonspecific "wound"-type of inflammation, is an important mediator of the early dysfunction of transplanted islets in rodents. Although allogeneic islets stimulate NO production to a greater degree than syngeneic islets, the amounts of NO produced after either are significantly elevated above baseline. Inhibition of NO production by N(G)-monomethyl-L-arginine (NMA), markedly decreases the time needed to restore euglycemia after intraportal transplantation of syngeneic islets in diabetic rats. The dose of NMA used was not observably toxic, with no significant changes in blood pressure, hepatic artery blood flow, serum hepatic enzyme levels, or in weight compared with control animals. In rat recipients of intraportal syngeneic transplants, evidence that NO is produced at the site of implantation includes (1) an early and transient increase in posttransplant hepatic vein nitrate levels (pretransplant, 90 microM; 24 hr, 230 microM; 48 hr, 250 microM; 72 hr, 170 microM; and 96 hr, 140 microM), (2) concurrent appearance of inducible NO synthase mRNA in liver extracts, and (3) immunohistochemical localization of inducible NO synthase within the transplanted islets. Suppression of NO production or inhibition of NO activity is a potential strategy to increase the early function and engraftment transplanted islets in the clinical setting.

Evolution of kidney, pancreas, and islet transplantation for patients with diabetes at the University of Minnesota

Transplantation began at the University of Minnesota in 1963. Treatment of diabetes and its complications has been emphasized since 1966, when the first pancreas-kidney transplant was done. Of 3,640 kidneys transplanted by 1992, 1,373 were for diabetic recipients, including 658 from living donors and 715 from cadaver donors. The results progressively improved; since 1984, survival rates of kidney grafts have been similar for diabetic and nondiabetic recipients, with three fourths of the grafts functioning at 4 years. As of 1992, 501 pancreas transplants had been done, including 170 simultaneous with a kidney, 142 after a kidney, and 188 alone for nonuremic diabetic patients; again, the results have improved: by the 1990s, graft survival rates were similar in the 3 recipient categories. Successful pancreas transplants have been shown by our coworkers to stabilize or improve neuropathy and prevent recurrence of diabetic nephropathy in kidney grafts. In an attempt to simplify endocrine replacement therapy, we have done 63 human islet transplants, 34 as allografts for patients with type I diabetes and 29 as autografts after total pancreatectomy to treat chronic pancreatitis. Insulin independence occurs for about 50% of islet autograft recipients. Two recent islet allograft recipients treated with 15-deoxyspergualin have had sustained insulin independence. We anticipate that endocrine replacement therapy by transplantation will become routine for diabetic patients as methods to prevent rejection are refined.