Pancreatic islet transplantation future prospects

There is good evidence that the long-term complications of diabetes are caused by poor control of blood sugar, even in patients where intensive glucose monitoring is used to control insulin therapy. Pancreatic transplantation offers the potential for normalisation of glucose metabolism, but at the cost of major surgery and immunosuppression. The possibility of separating the insulin-secreting tissue from the exocrine gland has many attractions. Isolated pancreatic islets are small enough to allow transplantation as free grafts by an injection technique. Furthermore, it may be possible to modify the graft in such a way as to prevent rejection with minimal or no immunosuppression. For pancreatic islet transplantation to become useful in clinical practice it will be necessary to develop efficient techniques for harvesting viable islet tissue in adequate quantities, identify a suitable site for transplantation and prevent rejection. Over the past 20 years experimental models of islet transplantation have proven the potential of this approach, but until recently it has not been possible to translate these experiments into clinical practice. Recently, there have been significant advances in the techniques available for separation of islets from the pancreas of large mammals and man, and recent clinical trials of islet transplantation have shown evidence of short-term function. However, significant problems remain, particularly those of rejection and the maintenance of long-term function, before introduction of clinical islet transplantation as standard therapy for diabetes can be expected.