LOS ANGELES -- Researchers have demonstrated for the first time that the progression of Type-1 diabetes can be halted -- and possibly reversed -- by a stem cell transplant that preserves the body's diminishing ability to make insulin, according to a study published today.
The experimental therapy eliminated the need for insulin injections for months or even years in 14 of 15 patients who were recently diagnosed with the disease. One subject, a 30-year-old male, hasn't taken insulin since his stem cell transplant more than three years ago, according to the study in the Journal of the American Medical Association.
The study suggests a new avenue for treating the intractable disease, in which the immune system destroys insulin-producing beta cells in the pancreas. Without insulin, patients can't metabolize sugar and risk developing nerve damage, cardiovascular disease, kidney failure, and blindness.
Patients with Type-1 diabetes typically compensate by monitoring their blood sugar levels every few hours and injecting themselves with insulin as many as five times a day.
After the stem cell treatment, "patients are absolutely medication-free; they're off insulin," said Dr. Richard Burt, chief of the division of immunotherapy at Northwestern University's Feinberg School of Medicine and senior author of the study.
The strategy is similar to an approach showing some success in treating other immune-system disorders, such as rheumatoid arthritis, lupus, and multiple sclerosis.
"We all realize that without addressing the problem at the level of the immune system, we'll never really beat Type-1 diabetes," said Dr. Francisco Prieto, who treats diabetics in Elk Grove, Calif., and wasn't involved in the study. "This is very encouraging work."
Burt and his colleagues cautioned that they don't yet know whether the fix is permanent and, if it is not, how long it will last. One of the subjects was insulin-free for one year but then relapsed after a respiratory viral infection, said lead author Dr. Julio Voltarelli, associate professor at Ribeirao Preto Medical School at the University of Sao Paulo in Brazil.
The researchers also cautioned that the process is not without risk, with patients vulnerable to infection during part of the therapy.
But other doctors said that even if the benefits of the therapy are temporary, the research provides valuable insight into the mechanism behind the disease.
The Juvenile Diabetes Research Foundation in New York estimates that as many as 3 million Americans have Type-1 diabetes, with between 30,000 and 35,000 new cases diagnosed each year.
The age of onset is considerably younger than for Type-2 diabetes patients, who can still make insulin but can't use it efficiently.
The stem cell approach mirrors the bone marrow transplants used to treat patients with certain cancers and blood diseases. The idea is to wipe out the faulty immune system and replace it .
In the study, 15 Brazilian patients were treated within a few months of their diagnosis, before their immune systems had the chance to eradicate all of their insulin-producing cells.
The study was conducted in Brazil because of Voltarelli's interest in the experiment. It was funded by the Brazilian Ministry of Health and other sources.
The patients, who ranged in age from 14 to 31, were treated with drugs and hormones that prompted the body to produce hematopoietic stem cells and send them from the bone marrow into the bloodstream, where they were extracted by a special machine.
About two weeks later, the patients checked into the hospital and received chemotherapy and other drugs to kill off their immune systems over five days.
After a day of rest, they were infused with their own hematopoietic stem cells, which took about eight to 12 days to establish a new immune system. In the interim, they were given antibiotics to protect against infections.
The treatment had no effect on one patient, whose disease had already progressed too far, doctors decided. Of the remaining 14 patients, 12 were able to stop taking insulin shortly after their transplants. Altogether, five patients have not needed insulin injections for at least 23 months, and two have been insulin-free for more than 18 months.
Even if patients continue to require insulin shots, the treatment should be considered a success if it halts the destruction of beta cells, said Dr. Jay Skyler, with the Diabetes Research Institute at the University of Miami Miller School of Medicine, who wrote an editorial accompanying the study.