With Cell Transplants, Diabetics Able to Stop Insulin Shots
WebMD News Archive
May 19, 2000 (Washington) -- Eight severely afflicted type 1 diabetics are now living normal lives without insulin, thanks to experimental transplants of insulin-producing cells combined with less toxic anti-rejection drugs.
The Canadian surgeon who pioneered the technique says it has the potential to be a cure for type 1 diabetes, a condition that is also called juvenile diabetes and that often leads to disabling and life-threatening complications such as blindness, kidney failure, and heart disease.
So far, a teacher from the Alberta province has lived without insulin shots for 14 months, the longest of any transplant recipient. Before that, the teacher was subject to repeated diabetic comas and hospitalizations, says the researcher, A.M. James Shapiro, MD, director of the clinical islet and pancreas transplant programs at the University of Alberta in Edmonton.
The other seven adult patients have been off insulin injections for about 11 months. But Shapiro says this doesn't mean the treatment, known as the Edmonton Protocol, is for everyone.
"It's only for those who fail on injectable insulin," he told those attending a meeting of the Juvenile Diabetes Foundation International here. "We don't think it's suitable for use in children right now until we know for sure what the long-term risks of these drug combinations are."
Use of the newer anti-rejection drugs, including tacrolimus, sirolimus, and daclizumab, is crucial to the transplants' success. These drugs are much less likely to damage the insulin-producing islet cells than steroids, which doctors traditionally give transplant patients. Until this new immunosuppressive combination was developed, Shapiro says, transplant efforts had been "dismal." Now, he says, there's no evidence the transplants are being rejected.
Type 1 diabetes occurs when the immune system attacks and destroys the islet cells in the pancreas. These cells normally produce the hormone insulin, which regulates the body's blood-sugar level. About a million Americans have the disease, which can occur at any age.
Transplanting a pancreas, the organ that makes the islet cells, can reverse diabetes. But it is a tough, and relatively risky, procedure.
Instead, Shapiro and his colleagues remove the pancreases from the donors, extract the islet cells, and purify them. The millions of cells are then injected into a vein leading to the liver. The liver then starts to function as a healthy pancreas. In about half the cases, the patient is home in 24 hours. The side effects are modest, and include mouth ulcers and bleeding at the injection site.
"Islet transplants work," Shapiro says. "These patients have a new life without insulin; they have very good sugar control. We predict, but we cannot prove right now that this truly will stop the secondary complications" of diabetes. He hopes that additional studies will show his islet transplants can last for years, and that the limited supply of cells available for transplant will be greatly increased by cloning or by harvesting pancreatic tissue from specially bred animals.