Monday 21st February, 2005
Two islet transplant procedures; single donor islet transplantation and the first living donor islet cell transplant offers promise for diabetics.
Patients with type 1 diabetes who received islet transplantation from a single donor pancreas were insulin independent one year later, according to a study in the February 16 issue of JAMA, a theme issue on medical applications of biotechnology.
Type 1 diabetes remains a therapeutic challenge, according to background information in the article. The success rate of islet (cells that produce insulin to control blood sugar levels) transplants has recently been increased markedly by transplanting a higher number of islets prepared from 2 to 4 donor pancreases. However, for islet transplants to become a widespread clinical reality, additional advances are still needed. In particular, restoration of insulin independence must be achieved with a single donor, as is also the case with pancreas transplants, to reduce the risks and costs and increase the availability of islet transplantation.
Bernhard J. Hering, M.D., of the University of Minnesota, Minneapolis, and colleagues conducted a study to assess the effectiveness and safety of islet transplantation from a single pancreas. The trial was conducted from July 2001 to August 2003 and enrolled eight women with type 1 diabetes.
During the trial there were no serious, unexpected, or procedure- or immunosuppression-related adverse events. All eight recipients achieved insulin independence and freedom from hypoglycemia. Five remained insulin-independent for longer than 1 year.
"Our results mark a distinct advance in islet transplant efficacy. We not only achieved insulin independence using islets from only 1 donor pancreas [as compared with 2 to 4 in another trial], we also achieved superior glycemic control (as evidenced by normal results of oral glucose tolerance testing in 4 of 5 recipients with sustained insulin independence) using significantly fewer islets," the authors write. "These findings may have implications for the ongoing transition of islet transplantation from clinical investigation to routine clinical care."
"While these findings may suggest a distinct advance in islet transplantation, further study in a larger population with longer follow-up will be critical to assess the risk-benefit ratio of this emerging therapeutic option," the researchers conclude.
World-first living donor islet cell transplant a success
EDMONTON/KYOTO ? A University of Alberta and Capital Health surgeon, well known for his pioneering work in developing the Edmonton Protocol treatment for diabetes, has taken another important step in the fight against diabetes.
On January 19, at Kyoto University Hospital, Dr. Koichi Tanaka and Dr. James Shapiro, along with a team of Japanese surgeons, removed part of a 56-year-old woman's pancreas. Dr. Shinichi Masumoto then isolated the living islets in the Kyoto Centre for Cell and Molecular Therapy. Under Dr. Shapiro's supervision, the team then transplanted the insulin-producing cells into the woman's 27-year-old diabetic daughter.
The transplanted islets began producing insulin within minutes, explains Dr. Shapiro. "The reason I'm so excited about this is because normally the Edmonton Protocol is done with islets from brain-dead organ donors. Those islets are often severely injured from cold storage, transport time and the pancreas is severely damaged by toxins which circulate in the blood stream after brain death."
"Our expectation is that these islets from near-perfect organs will work better, although it's too early to tell," he says.
The recipients use the same drugs to prevent organ rejection as are used in the Edmonton Protocol.
Dr. Shapiro was invited to participate in the operation in Kyoto, Japan, where he originally did living donor liver transplant training with Dr. Tanaka. Dr. Masumoto was previously based in Seattle and had been involved in Dr. Shapiro's international trial of the Edmonton Protocol before returning to Japan. Dr. Shapiro first suggested the idea of starting a living donor islet transplant program in Kyoto while lecturing there three years ago. Cadaveric organ donors are scarce in Japan, and living donation has very established roots in liver and kidney transplantation there.
"Living donor islet transplants could allow many more desperate patients with type 1 diabetes to get successful islet transplants," says Dr. Shapiro. "The donor operation is relatively safe, but is not entirely devoid of serious potential risk," he added.
A shortage of donor islet cells is the biggest obstacle preventing implementation for all patients who need it, Shapiro added.
The mother of the diabetic daughter was in perfect health, while her daughter has been on the cadaver donors transplant list since September 2004. Before the surgery, the woman had been subject to severe low blood sugar coma attacks, and her glucose control has been transformed by the transplant.
Dr. Tamer Fouad, M.D.
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