Researchers at Peptor, a biochemical company in Rehovot, Israel, have developed a protein that blocks the destruction of B-cells. Type I diabetes occurs when these insulin-producing cells are progressively destroyed by the patient's own immune system.
Stopping the destruction of the cells seems to control a patient's need for insulin injections, and if the therapy is started early enough, the researchers suspect it could even prevent the illness.The study appears in the Nov. 24 issue of The Lancet.
Type I, or insulin-dependent diabetes, accounts for 5 percent to 10 percent of the 16 million cases of diabetes in the United States. The disease leaves the body without enough insulin and often leads to complications, including blindness and cardiovascular and kidney problems.
Dana Elias, an immunologist and vice president of research and development at Peptor, led a study of 35 men, ages 16 to 55 years, who recently were diagnosed with Type I diabetes. The men were tested for levels of C-peptide, an indicator of normal insulin production, and randomly assigned to two groups. Eighteen received an injection of an experimental protein called DiaPep277 at the start of the study and again after one month and six months. The remaining 17 men received placebo injections.
Over 10 months, the patients receiving the placebo experienced a continual drop in C-peptide levels and gradually lost B-cells.
However, the patients receiving DiaPep277 maintained normal levels of C-peptide.
The protein also had a significant effect on insulin requirements. "All the patients were already dependent on insulin when they started the study," says Elias, and all of the men continued to require insulin.
However, in the first year after diagnosis, the amount of insulin that a patient needs normal usually increases as the body loses B-cells. "In the placebo group, we saw a very steep increase in the daily amount of insulin the patients were using. In the DiaPep277-treated group, there was basically no change." In fact, at the end of the 10-month study, the DiaPep277 group needed roughly half the insulin of the placebo group, Elias says.
Elias says some immune-system cells can promote inflammation, contributing to the destruction of the B-cells, but other cells secrete immune-system hormones, or cytokines, which can suppress inflammatory cells.
"What DiaPep277 is doing is triggering the second group of cells, making them more active. "Basically, we're triggering the built-in protective arm of the immune system," says Elias.
"If you were to treat [patients] very early, you might be able to totally prevent diabetes," she says.
Dr. Zihai Li, assistant professor of medicine at the University of Connecticut, says the findings, while interesting, are very preliminary. "The follow-up is pretty short. It's also kind of a small study," he says.
The patients also had been diagnosed with diabetes, meaning the therapy wasn't truly preventive, Li says. However, he says "the therapy is novel," and it merits examination in a larger, longer trial.
Elias says that while preliminary studies indicate that DiaPep277 has few side effects, no clear, long-term data about any complications related to the protein is available. Elias says that Peptor is planning a larger trial in the United States starting in early 2002.
What To Do: Learn more about Type I diabetes from the Juvenile Diabetes Research Foundation International, the National Institute of Diabetes & Digestive & Kidney Diseases or the American Diabetes Association.