Islet Cell Advances May Fight Diabetes

Nov. 29, 2005 -- An advance in an experimental treatment that promotes natural insulin production among people with type 1 diabetes may mean that more patients will one day be able to live without daily insulin injections.

Researchers used ultrasound guidance to help them inject and transplant insulin-producing cells, known as beta-islet cells, into the liver. They also developed a technique that appears to lower the risk of bleeding complications associated with the procedure.

Their islet-transplantation technique is minimally invasive and could potentially be done as a same-day procedure, says researcher Saravanan Krishnamoorthy, MD.

Krishnamoorthy presented the findings in Chicago at RSNA 2005, the annual meeting of the Radiological Society of North America.

"There are still problems that have to be addressed, but this could be done as an outpatient procedure," he tells WebMD.

Making Insulin

Although still experimental, islet-cell transplantation offers the promise of helping large numbers of people with type 1 diabetes lead more normal lives.

People with this type of diabetes produce little or no insulin, the hormone that helps cells break down glucose (sugar) in the blood for fuel. This is due to the body's destruction of the islet cells that make insulin. Islet cells are found in the pancreas.

Type 1 diabetes has been traditionally known as "juvenile" diabetes and requires lifelong insulin supplementation.

The transplantation of beta-islet cells from donor pancreases has been shown to promote natural insulin production among patients. But like other transplant patients, islet recipients must take powerful immune-suppressing drugs to prevent rejection of the foreign cells.

About 400 patients worldwide had received islet cell transplants from donor pancreases as of late last year, with varying degrees of success.

Ultrasound Technology

The study reported by Krishnamoorthy and colleagues at the University of Minnesota, Minneapolis included 13 patients with poorly controlled type 1 diabetes.

The researchers used ultrasound technology to locate the best site for islet cell infusion. They were able to transplant cells on the first attempt in two-thirds of cases and were successful on the second attempt in most other patients.

They also used a specialized technique to help prevent bleeding complications from the needle used to inject the cells.

No major complications or deaths were reported among the patients, who were followed for a month after receiving the islet cells. All 13 were producing insulin on their own. Transplant recipients had some reported anemia (lower blood count) and abnormal liver enzyme levels.

Hurdles Remain

American Diabetes Association spokesman Nathaniel Clark, MD, says islet cell transplantation is a promising technique for the treatment of type 1 diabetes. But he adds that some major hurdles remain for the therapy.

Rejection of transplanted cells remains a big problem, and the long-term side effects of currently available antirejection drugs are poorly understood. But better antirejection drug protocols are helping to improve long-term results and minimize the risks to patients.

Researchers are also working to develop methods of transplanting islet cells that will reduce or eliminate the risk of rejection. One approach involves coating islet cells with a gel that prevents the immune system from attacking them.

Collecting enough islet cells to transplant is also a major problem. Two donor pancreases are currently needed to provide the number of islet cells used for a single transplant.

Researchers are investigating whether islet cells from pigs are suitable for human transplant. And human embryonic stem cells could potentially produce suitable cells for transplant.

Despite the hurdles, Clark says islet transplantation has the potential to transform the treatment of type 1 diabetes.

"This continues to be one of the most exciting and promising techniques to potentially produce a cure for this disease," he says.