Islet cell transplantation for the treatment of diabetes

In islet cell transplantation, insulin-producing beta cells are taken from a donor's pancreas and transferred into a person with diabetes. Once transplanted, the donor islets begin to make and release insulin, actively regulating the level of glucose in the blood.

What Are the Benefits of Islet Cell Transplantation?

A successful islet cell transplant can significantly improve the quality of life for a person with diabetes.

Once transplanted, the islet cells automatically monitor sugars levels and can regulate insulin levels by delivering the appropriate amounts needed to normalize blood glucose levels, even as the body's needs change (for example, after exercising or eating).

Successful transplantation can provide the following benefits:

• It can eliminate the need for frequent blood glucose measurements and the need for daily insulin injections. Although only a few people are completely free of insulin injections a year after transplantation.
• It can provide more flexibility with meal planning.
• It can help protect against the serious long-term complications of diabetes, including heart disease, kidney disease, stroke and nerve and eye damage.

What Are the Risks of Islet Cell Transplantation?

As with any organ or tissue transplant, rejection of the donor cells is the greatest challenge. The immune system serves to protect the body from "invading" substances that do not belong -- bacteria and viruses, for example. Even when needed donor tissue is transplanted, the recipient's immune system recognizes it as "foreign" and tries to destroy it. This attack on the donor tissue is called "rejection."

All transplant recipients must take, for the rest of their life, strong drugs to suppress the immune response and prevent rejection. Many of these drugs have serious side effects. The long-term effects of these immunosuppressive or anti-rejection drugs are not yet known, but it is suspected that they may increase the risk of cancer.

How Successful Is Islet Cell Transplantation?

Scientists developed the procedure for isolating islet cells in the 1960's. The first transplantation attempts, which began in the 1990's, succeeded only 8% of the time, which was attributed to the fact that anti-rejection drugs available at the time interfered with insulin's effectiveness.

But in 1999, a clinical trial conducted at the University of Alberta in Edmonton, Canada, brought new hope. Using enhanced techniques to collect and prepare the extremely fragile donor islet cells, as well as using improved anti-rejection drugs, the researchers achieved a 100% success rate. All of the patients in their trial were freed from the need for insulin for at least one month. The process followed by the researchers -- dubbed the "Edmonton Protocol," -- is still being studied in clinical trials around the world.

Can Anyone With Diabetes Get an Islet Cell Transplant?

Typically, candidates for islet cell transplantation are between the ages of 18 and 65, have had type 1 diabetes for more than 5 years, and are experiencing diabetes-related complications such as frequent periods of unconsciousness due to lack of insulin and early signs of kidney problems that could lead to kidney failure.