Is Islet Transplantation a Realistic Therapy for the Treatment of Type 1 Diabetes in the Near Future?

Since Banting and Best’s discovery of insulin in 1921, the administration of exogenous insulin has been the primary treatment for type 1 diabetes. Although this therapy has enabled millions to survive and lead fairly normal lives, it has fallen short of a cure. Type 1 diabetes affects millions of individuals and is associated with multiple medical problems, including renal failure and a reduced life expectancy. Tight control of blood glucose levels, achieved with intensive insulin therapy, reduces the secondary complications of diabetes.1 Unfortunately, such tight control often results in frequent episodes of hypoglycemia. In contrast to the results achieved with intensive insulin therapy, pancreas transplantation usually results in independence from exogenous insulin, normal glucose levels (both fasting and postprandially), normal HbA1c levels, and freedom from hypoglycemia.2 Pancreas transplantation is now widely accepted as a reasonable therapeutic option for many individuals with diabetes and either rapidly progressive or significant end-organ disease (e.g., renal failure) or severe metabolic instability (e.g., hypoglycemic unawareness).3 Nevertheless, whether one performs a pancreas transplant with systemic or portal venous drainage, both have significant morbidity and mortality rates.3, 4 Thus, most individuals with type 1 diabetes are not candidates for pancreas transplantation. What has been needed is a less morbid alternative for individuals who have the medical need for a pancreas transplant, but who are not surgical candidates for this operation. Islet transplantation may now meet this need. This article will review the current state of islet transplantation, with a particular focus on the reasons for the recent suc-