Pancreas versus islet transplantation in diabetes mellitus: How to allocate deceased donor pancreata?

Transplant options for the diabetic recipient include pancreas and islet transplantation. Pancreas transplantation has been increasingly performed in the last 3 decades with increasing success rates. Nevertheless, islet transplantation offers the advantage of being less invasive with fewer complications. However, current experience shows that multiple transplants are required to achieve and maintain insulin-independence in the intermediate term, and long-term function remains a problem even with multiple transplants. Early successes with single-donor islet transplants are encouraging and if maintained will largely substitute pancreas transplants. Currently, single-donor islet transplants have been shown to work in recipients with low insulin requirements who receive a pancreas from a donor with high body mass index. However, pancreas transplants from obese donors are associated with increased surgical risk. Therefore, it is logical to preferentially allocate obese donor pancreata to islet recipients. In addition, older donor (50 to 65 years) pancreata could be preferentially allocated to islets since their islet yield is still good, whereas they are associated with decreased survival in whole-organ pancreas transplants. With increasing efficiency and success of islet transplants the criteria for pancreas allocation for islets will need to be periodically reviewed.