Type 1 diabetes (T1D) destroys the pancreatic beta cells and the body’s capacity to produce insulin. Insulin replacement has been the main treatment for 100 years but it is not a cure for diabetes and it does not address the underlying mechanisms of disease.
Islet transplantation has been a successful treatment for over 20 years in a limited number of patients. The main indication for islet transplants is for T1D complicated by hypoglycaemic unawareness with frequent severe hypoglycaemia events. Two reports – one a prospective multicentre trial in the US and the other a large series of 255 islet transplants from Canada - have shown that islet transplantation can be carried out safely in major centres and treats hypoglycemia very effectively even when insulin independence is not achieved. Patient reported outcome measures reflect the success of the procedure. However, shortage of suitable donor organs and the need for immunosuppression to prevent allo-rejection and/or recurrence of autoimmunity limit its broad application. Islet autotransplantation is not subject to these limitations and is useful when pancreatectomy is being carried out in chronic pancreatitis.
New approaches to beta cell replacement will be built on the foundations laid by islet transplantation and will include much less limited cell supply and a variety of approaches to overcoming and evading immune attack.