Transplantation for type 1 diabetes mellitus. Whole organ or islets?

Two types of transplants are offered to patients with complicated insulin dependent diabetes mellitus: a) whole pancreas transplantation, b) pancreatic islet transplantation. A total of 29000 whole pancreas transplantations and 1500 islet transplantations have been performed worldwide until today. Patient survival for whole pancreas recipients is 85% five years after transplantation, whereas very few islet studies focus on patient survival. Graft survival for whole pancreas recipients is 90%, 70% and 45%, at one, five and ten years after transplantation respectively. On the other hand, only 44% of islet recipients are still insulin free, one year after engraftment. If the definition of a successful islet transplantation is not insulin independence but production of C-peptide, then 80% of the same islet recipients have a functioning graft by the end of the first post-transplant year. It is a known fact that whole pancreas transplantation has significant complications. The most common complications after whole organ transplantation include technical failures, acute rejection and CMV infection, whereas islet transplantation is associated with portal vein thrombosis, bleeding, emergency exploratory laparotomy, liver steatosis and rapamune-induced mouth ulcers. The cumulative cost of a whole organ transplantation is about ?40,000. On the other hand, the cumulative cost of a pancreatic islet transplant is estimated to be higher than ?120,000. Whole organ transplantation halts the late complications of diabetes, namely vasculopathy, retinopathy, nephropathy and neuropathy. Although similar claims are made for islet transplantation, its impact on long-term diabetic complications is possible but not proven. Currently, in North America, lean young donors are utilized for whole organ transplants, whereas overweight or older donors are utilized for islet transplants. In conclusion, although islet transplantation is an extremely promising therapy and probably the way of the future, whole organ transplant is still the gold standard according to evidence-based medicine.