It is not possible even with the most intensive conventional insulin regimens to control Type 1 diabetes well enough to normalise metabolic control or totally prevent complications. For this, a closed loop is needed, whereby circulating insulin levels are regulated on a moment to moment basis according to needs. Only pancreatic transplantation currently achieves this. Over 20000 whole pancreas transplants have been done worldwide and a one year graft survival rate of over 80% is routinely achieved. Dramatic effects on quality of life, incidence of complications and life expectancy have been reported. However, major surgery is involved and post-operative morbidity is substantial. Since patients with Type 1 diabetes lack only beta cells, which comprise less than 2% of the pancreas, the injection of purified islets, obviating the need for surgery, offers an attractive alternative. However, until 2000 the one year insulin independence rate of isolated islet transplantation was only 8%. In that year, Dr James Shapiro in the University of Alberta, turned the islet transplant world on its head with what is now known as the Edmonton protocol. As well as meticulous attention to methodological detail, he completely changed the immunosuppressive regimen, and in particular left out steroids. He also recognised the need to transplant more islets than had been done previously, which often meant transplanting patients with islets from two donors to achieve the necessary graft size. To date, more than 200 islet transplants have been done with the new protocol, and an insulin independence rate almost identical to whole pancreas transplantation is now being reported. It remains to be seen whether long term graft loss differs from vascularised pancreas transplants, what additional steps can be taken to improve outcome, whether further 'top-up' transplants can be given, and whether the same effects on complications and survival will be seen.
22 - 24 Mar 2004
British Endocrine Societies