Glial cell line-derived neurotrophic factor enhances human islet posttransplantation survival.

BACKGROUND: Development of pretransplantation islet culture strategies that preserve or enhance ß-cell viability would eliminate the requirement for the large numbers of islets needed to restore insulin independence in type 1 diabetes patients. We investigated whether glial cell line-derived neurotrophic factor (GDNF) could improve human islet survival and posttransplantation function in diabetic mice. METHODS: Human islets were cultured in medium supplemented with or without GDNF (100 ng/mL) and in vitro islet survival and function assessed by analyzing ß-cell apoptosis and glucose stimulated insulin release. In vivo effects of GDNF were assessed in streptozotocin-induced diabetic nude mice transplanted under the kidney capsule with 2000 islet equivalents of human islets precultured in medium supplemented with or without GDNF. RESULTS: In vitro, human islets cultured for 2 to 10 days in medium supplemented with GDNF showed lower ß-cell death, increased Akt phosphorylation, and higher glucose-induced insulin secretion than islets cultured in vehicle. Human islets precultured in medium supplemented with GDNF restored more diabetic mice to normoglycemia and for a longer period after transplantation than islets cultured in vehicle. CONCLUSIONS: Our study shows that GDNF has beneficial effects on human islet survival and could be used to improve islet posttransplantation survival.