With Cell Transplants, Diabetics Able to Stop Insulin Shots
"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.
Additional studies of islet transplantation are planned in Canada and in the U.S., with funding from the National Institutes of Health.
In spite of the progress that has been made in recent years in controlling diabetes, associated conditions like kidney disease, blindness, or lower limb amputations remain a tremendous problem. Until recently, it wasn't clear what caused these long-term consequences. Now, according to Eva Feldman, MD, Ph.D, a neurologist at the University of Michigan Health System, it appears that high sugar levels in the blood have a toxic effect on the body's nerves.
In another presentation at the meeting, she said that studies in both animals and people have shown that increased sugar levels, as seen in diabetes, overload the mitochondria that serve as an energy source for cells in the body. The result is an increased level of waste products that can't be cleared by the body's 'antioxidative' defense mechanism. The rogue wastes then go on to damage healthy tissues, which ultimately leads to cell death though what's called 'oxidative stress.'
"So with diabetes, what you get is progressive loss of nerve cell fibers, and when you have this loss of nerve fibers, you lose your ability to feel," Feldman says. What's needed, she says, are new drugs that reduce this process. Currently, she says, two studies of a vitamin E-like compound, called alpha-lipoic acid, are under way.
"I give all my patients 2,000 units of vitamin E," Feldman says, "and I do it because it's the best antioxidant available."