Normoglycemia and preserved insulin secretory reserve in diabetic patients10-18 years after pancreas transplantation

Pancreas transplantation is a controversial form of therapy for type 1 diab etes. A major obstacle to acceptance of this procedure for many physicians is the lack of demonstrable long-term success. We performed these studies t o assess the hypothesis that successful pancreas transplantation is efficac ious in normalizing endogenous insulin secretion and glycemia in the long t erm (1-2 decades). Sixteen patients with a history of diabetic complication s who had undergone a transplant 10-18 years earlier involving either a who le or a segment of pancreas were recruited for measurements of fasting plas ma glucose, HbA(1c), intravenous glucose tolerance, and insulin secretory r eserve. All patients were taking immunosuppressive drugs, but none was usin g insulin or other hypoglycemic agents. All recipients had normal levels of fasting blood glucose, intravenous glucose tolerance, and HbA(1c), and 15 of 16 stated that their quality of life had improved after transplantation. They had intact acute insulin responses to intravenous pulses of glucose a nd to arginine and insulin secretory reserve. Glucose potentiation of argin ine-induced insulin secretion, the measure of insulin secretory reserve, co rrelated significantly (r = 0.095, P < 0.001) with the acute insulin respon se to intravenous glucose, rendering the latter a much simpler and valid me asure of functional beta-cell mass. We conclude that successful pancreas tr ansplants are efficacious for periods as long as 1-2 decades in returning e uglycemia to type 1 diabetic patients by restoring endogenous insulin secre tion and insulin secretory reserve. Thus, concern about long-term deteriora tion, as distinct from rejection, should not be a major obstacle when decid ing whether to recommend pancreas transplantation.