Puzzling Ailment

Hope for juvenile diabetics

The disease strikes some 1.5 million Americans, usually between infancy and age 40. Yet unlike the other major form of diabetes, which afflicts some 8.5 million older Americans, it can never be controlled by diet alone. Juvenile-onset diabetes requires daily injections of insulin, the hormone used by the body to help burn sugar. But even with life-giving insulin therapy, there may be severe complications, including blindness, kidney failure, heart attacks and stroke. Partly because insulin keeps people alive long enough to bear children who may inherit the disease, the prevalence of diabetes has been increasing for the past several decades by a disturbing 6% a year.

Though neither cause nor cure has yet been found, researchers are pursuing several promising avenues of investigation that may give new hope to the young victims of this puzzling disorder. Items:

Artificial pancreas. Responding to shifting levels of sugar in the blood, the pancreas constantly adjusts its secretion of insulin, delivering more during meals, when larger quantities are needed, less during exercise or sleep. Daily insulin injections can correct a deficiency, but are not the whole answer: often the insulin level is above or below what it should be, and the blood's sugar fluctuates wildly, probably aggravating the diabetic's other problems.

Yale's Philip Felig and other doctors are now helping nature by fitting juvenile diabetics with miniature battery-powered pumps that continuously trickle insulin into their bodies. Weighing barely a pound, the artificial pancreases are worn on the belt or carried in a shoulder bag.

The pumps tap a 24-hr, insulin supply, feeding it at a slow, steady rate via a thin tube that ends in a needle inserted under the skin of the abdomen or thigh. Before meals, patients can override the pre-set instructions and briefly step up the dosage by pressing a button. One incidental benefit, reports Felig: blood fats, including cholesterol, seem to return to normal during treatment.

Pancreatic cell transplant. The problem in most juvenile diabetics is that the insulin-producing cells within the pancreas, called the islets of Langerhans, are no longer functioning properly. (In adult diabetics, insulin supplies are generally adequate, but somehow the body is unable to release them or use them properly.) Doctors have tried transplanting fresh islets from healthy pancreases, but the immune system tends to reject them.

Now Pathologist Paul Lacy and his colleagues at Washington University have devised a way to encourage islet survival--at least in laboratory animals. Taking healthy islets from rats, the team "incubated" them at room temperature for seven days, then injected them into diabetic animals, along with an immunosuppressive serum. More than 100 days later, the transplanted islets were still producing insulin in the diabetics, whose condition improved markedly. The next major question: Will this successful experiment in rats also work in man?

A viral trigger. Some scientists have long suspected that juvenile diabetes may be caused by a virus. Researchers at the National Institutes of Health and the National Naval Medical Center in Bethesda, Md., believe that they have finally found a firm link. Their evidence: the case of a ten-year-old boy who became severely diabetic and died only days after a flu-like illness. Post-mortem studies of his pancreatic tissue revealed a common, relatively harmless virus, Coxsackie B4.* Surprisingly, when it was injected into mice, they developed diabetes. This, along with other signs, strongly suggests that the virus triggered the boy's fatal illness.

Since Coxsackie B4 is so common, the researchers must explain why even more people do not develop diabetes. They theorize that other viruses may also be involved, as well as an inherited susceptibility to the disease and weaknesses in the immune system. But if juvenile diabetes is indeed essentially viral, doctors may eventually be able to develop a weapon similar to those used so successfully against other viral diseases: a diabetes vaccine.

* Named after the village in New York where the first of this viral group was found.

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