Japanese researchers reverse diabetes

Japanese researchers have successfully reversed a woman’s diabetes by transplanting insulinmaking cells (islets) from a living donor’s pancreas into her, reporting their results in a research letter published online today by The Lancet. This is the first successful operation of its kind using the islets from a living donor.

Since the success of islet transplantation in 2000 from the organs of dead donors, demand for the procedure has risen substantially and donors will soon be in very short supply. Islet transplantation from living donors represent an alternative approach to expand the potential donor pool, particularly in countries like Japan where the number of people donating their organs after death is low. Two previous attempts at transplantation from living donors have been carried out in US but were unsuccessful.

The donor was a 56-year-old woman who was the mother of the recipient. She had a compatible blood group and had healthy glucose and insulin concentrations. The recipient was a 27-year-old woman who had developed insulin-dependent diabetes when she was 15 years old. She had been admitted to hospital to control her frequent hypoglycaemic episodes, where her blood sugar levels would drop below normal. She received insulin injections every day in hospital.

Shinichi Matsumoto (Kyoto University Hospital, Japan) and colleagues isolated islet cells from the donor and transplanted them into the recipient’s liver at Kyoto University Hospital on Jan 19, 2005. After the operation they monitored the patient’s blood glucose. The investigators gradually weaned the recipient off insulin and she became insulinindependent 22 days after the transplantation. She has now been insulin independent for 2 months. The donor had no complications and both women have a healthy tolerance to glucose.

The authors state that islets from living donors are advantageous because they are more viable and more likely to function properly when compared with islets from the organs of dead donors. Living donors also overcome the problem of donor shortages for this type of transplant. The transplanted cells were derived from just half of a living pancreas and achieved similar effect to that achieved from the cells of two or more whole pancreases from dead donors. The difference in organ requirements probably indicates the improved potency of islets prepared from living donors, state the authors. They stress that long-term follow-up is necessary but believe that the transplant could last up to 5 years and even if the recipient needs insulin injections in the future she would be free from hypoglycaemic episodes. The authors also note that because the recipient did not have autoimmune type 1 diabetes the transplanted islets did not need protection against autoimmune disease. This factor might have been important for the success of the transplantation.

Dr Matsumoto concludes: “From our successful transplantation of living-donor islets for the treatment of unstable diabetes, our recipient achieved and maintained insulin independence after the procedure. We believe that such transplantation of living-donor islets can be an additional option in the treatment of insulin-dependent diabetes.”

In an accompanying Comment Stephanie Amiel (King’s College London, UK) states: “Until now, islet transplant programmes have used cadaveric donors. In Japan, cultural considerations severely restrict the use of cadaveric donors. For a patient with crippling hypoglycaemia in such societies, the only realistic donor source would be a living donor. She adds: “Islet transplantation is not yet a perfect technique. Insulin dependence is by no means certain; and is only likely in the very insulin sensitive.”