 
Diabetes Dateline
Winter 2007
Research News
Studies Test New Approaches to Islet Transplantation
Researchers from six medical centers in the United States and Canada have begun testing new approaches to islet transplantation in adults with hard-to-control type 1 diabetes. The clinical studies, funded by the National Institutes of Health (NIH), will determine whether changes to current methods of islet transplantation lead to improved, long-lasting control of blood glucose with fewer side effects.
In islet transplantation, clusters of insulin-producing cells, called islets, are extracted from a donor pancreas and infused into the portal vein of a recipient’s liver. In a successful transplant, the islets become embedded in the liver and begin producing insulin.
Currently, islet transplantation is appropriate only for people who already had a kidney transplant or who have severe hypoglycemia. As the procedure becomes safer and new sources of beta cells are developed, more people will benefit from transplantation.
In 2000, a research team led by James Shapiro, M.D., at the University of Alberta in Edmonton, Canada, reported sustained insulin independence in seven patients transplanted with islets from two to four donor pancreases and treated with an immunosuppressive regimen that omitted glucocorticoids, which are thought to be toxic to islets.
In the following years, other researchers replicated the “Edmonton protocol” and most centers adopted this approach to islet transplantation. The protocol greatly benefits some patients with severe type 1 diabetes, but two or more infusions of islets are usually needed and the islets tend to lose their insulin-producing function over time.
Continuing Research
Since the Edmonton advance, scientists have been working to lengthen the survival of donor islets and reduce the side effects––such as anemia, nerve and kidney damage, and vulnerability to infection––of drugs that prevent their destruction. In the newly launched studies, researchers will culture islets before transplantation to enhance their viability and compare the ability of specific anti-rejection drugs to improve the engraftment of donor islets with less toxicity.
The researchers are conducting pilot studies of experimental agents, as well as pivotal, or phase 3 studies, which modify the Edmonton protocol. If the phase 3 studies succeed in safely controlling blood glucose levels, the U.S. Food and Drug Administration may approve the procedure for people with poorly controlled type 1 diabetes.
“With these modifications, we hope to see prolonged islet function with less drug toxicity,” said Study Chair Camillo Ricordi, M.D., of the University of Miami. “If these approaches are successful, type 1 diabetes patients with severe problems controlling their blood glucose may have another treatment option for controlling their diabetes.”
For more information about these studies, see www.citisletstudy.org/index.html.
CITR Publishes Annual Report
The Collaborative Islet Transplant Registry (CITR) has published its 2006 annual
report, which analyzes information about islet transplant programs in North America between 1999 and 2005.
The number of human islet infusion procedures conducted in North America increased from 18 in 1999 to 120 in 2005. In the United States, islet transplantation is an experimental procedure regulated by the U.S. Food and Drug Administration. About 40 U.S. transplant programs either conduct islet transplantation or are in the process of starting a transplantation program.
The National Institute of Diabetes and Digestive and Kidney Diseases funds the CITR.
All CITR reports are available at www.citregistry.org.
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NIH Publication No. 07–4562
March 2007
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