Jackson Lab work hopeful for Type 1 diabetics

BAR HARBOR – Researchers at The Jackson Laboratory have announced a new genetic procedure using mice that may prove valuable in the treatment of humans with Type 1 diabetes, formerly known as juvenile-onset diabetes. Although a clinical application involving people is still just a bright spot on the horizon, the breakthrough offers new hope to the millions who suffer from the disease worldwide.

In a report released today, researchers explained their progress in preventing the rejection of insulin-producing cells, called islets, transplanted from the pancreas of an organ donor into the liver of a diabetes patient. A collaboration with scientists at the Albert Einstein College of Medicine in New York City, the research is featured in the May issue of the medical journal Diabetes.

Islet transplantation has been around for many years, but a refined version called “the Edmonton Protocol,” developed in Canada about four years ago, represents “a huge advance,” according to David Serreze, a senior diabetes researcher at The Jackson Lab. Under the Edmonton model, hundreds of diabetics have received transplants, most of them successfully stabilizing their blood sugar levels and managing their disease without insulin.

But there’s a downside. People who undergo the transplant can anticipate a lifetime of taking powerful medications to keep the new cells from being attacked by the same overwrought immune system that destroyed their own insulin-producing capability.

Medications effectively dampen the immune system and keep it from attacking the transplanted cells and new cells they generate. But a suppressed immune system spells trouble for the essential functions of protecting the body against disease.

People who take these drugs can die from infections that would hardly slow down a healthy person, as well as suffer other unpleasant and dangerous side effects. Many candidates for a islet transplants hesitate to undergo the promising procedure because of the complications of the long-term drug follow-up.

The breakthrough announced today by The Jackson Lab envisions an alternative to immunosuppressive drug therapy for future islet recipients.

Researcher Serreze says the process developed by scientists using mice involves a cultivated case of mistaken identity.

Genes, altered to mimic special protein-producing structures produced by certain respiratory viruses, are injected into developing mouse embryos. In their native viruses, the proteins are uniquely able to deflect the immune system’s hostilities, allowing the virus to replicate undisturbed.

The look-alike genes develop in the insulin-producing cells of the mouse pancreas, “fooling” the immune system into looking for a less-vulnerable enemy.

Serreze emphasized that the procedure is “pure research” and has no current or near-future application for treating diabetics. Long-term, he said, it offers real hope for protecting against the rejection of transplant cells.

Even further down the road, it may be possible to prevent diabetes in developing human embryos. But that, he acknowledged, “leads into all sorts of Frankenstein issues.”