Islet transplant – a secure future for cellular replacement therapy in diabetes

Outcomes in clinical islet transplantation have recently been transformed, following the introduction of steroid‐free, sirolimus based immunosuppression and the development of more refined methods for islet isolation from the donor pancreas. With the ‘Edmonton Protocol’, currently 85% of patients (28 completed transplants) remain free of insulin at the one year time‐point, and three in four patients remain free beyond three years. Variants of this protocol have now been successfully replicated in over 150 patients worldwide. Complete normalisation of glycated haemoglobin suggests that this therapy is likely to prevent, stabilise and possibly reverse early complications of diabetes. Progress with single donor islet transplant will allow many more patients with type 1 diabetes to be treated, but will fail to meet the enormous demand for this type of therapy.

Development of safer, low‐dose anti‐rejection therapies with very low risk of cancer or infectious complications is likely to further broaden the indications for islet transplant therapy in diabetes. If tolerance (or near‐tolerance) could be safely induced, protecting against both autoimmune and alloimmune rejection, then islet transplantation could possibly be applied in children, possibly allowing the use of laparoscopic live donor distal pancreatectomy to expand the available donor source. Recent progress both in stem cell biology and in xenotransplantation suggests that ultimately a limitless source of insulin secreting tissues will be found. The light at the end of the tunnel for patients with type 1 diabetes just got brighter. Copyright © 2003 John Wiley & Sons, Ltd.