Type 1 diabetes has long been difficult to manage with little hope for a cure.

But in a potential breakthrough, Children's Hospital in Pittsburgh has begun human clinical trials to test a vaccine designed to block the autoimmune response that kills insulin-producing beta cells in the pancreas, resulting in Type 1.

Safety trials on the novel method of correcting Type 1 are under way. If the vaccine is deemed safe, the study will enter phase II, to test whether it succeeds in restoring insulin production in children newly diagnosed with Type 1. There's additional hope the process can prevent the disease in people predisposed to develop it and restore some insulin production in those who have had Type 1 for years.

Drs. Massimo Trucco and Nicholas Giannoukakis at Children's Hospital already have proven success in mice. They expect results in human clinical trials in 2010.

If fully successful, the process would require a shot with perhaps an annual booster to prevent T-cells from resuming their attack on beta cells.

Insulin is the hormone that allows blood glucose to enter cells and be used as energy. Insulin injections, dietary measures, exercise and blood-glucose monitoring are necessary to prevent high blood glucose levels that prompt heart disease, strokes, kidney failure, blindness and circulation problems that can lead to limb amputations.

Correcting the problems is complex.

The Pitt team uses artificially produced "microspheres," or microscopic containers loaded with nucleic acid. When injected under the skin of mice, the microspheres are swallowed by dendritic cells, or white blood cells, that fight infection. The microspheres release their load of nucleic acid, which prevents the dendritic cells from producing the rogue proteins that signal T-cells to wage an autoimmune attack on beta cells.

The pancreas then can regrow beta cells and produce insulin naturally. How long the beneficial effect will last, if it works at all, has yet to be determined.

Previously, Drs. Trucco and Giannoukakis figured out a more complex method of altering dendritic cells to halt T-cell attacks on beta cells. Use of microspheres simplifies the process and involves only an injection -- rather than a lengthy dialysis type procedure -- to initiate the curative treatment.

"This is a very exciting approach because in many ways it simplifies what the dendritic-cell approach is all about," said Dr. Michael Clare-Salzler, a University of Florida endocrinologist who is doing similar research. "We've been the crazies in left field, but for me it makes ultimate sense.

"Bottom line, this approach is hopeful," he said. "I'm a big fan of Nick and Massimo. They are great scientists and excellent people, and it's great to see them having success."

If the process works in humans, there's concern it might last only a few months. If all goes well, there's hope the process will work with only occasional boosters.

That's the hope of nearly 1 million people in the United States with Type 1, including one in every 400 to 600 children.

"I always said my only dream was to have one patient eat ice cream without feeling guilty," Dr. Trucco said. "If I do that for any child with diabetes, I will feel that I didn't waste my life."