Stem-cell therapy can halt early diabetes, study says
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 run the risk of 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 in Chicago and senior author of the study.
The strategy is similar to an approach that has shown some success in treating other immune-system disorders, such as rheumatoid arthritis, lupus and multiple sclerosis.
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 of medicine at Ribeirao Preto Medical School at the University of Sao Paulo in Brazil.
The researchers also cautioned that the process is not without risk because patients are vulnerable to infection during part of the therapy. Burt’s research group at Northwestern has performed 170 stem-cell transplants to treat a variety of immune-system disorders and two patients have died from the treatment.
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.
“It’s a big deal,” said Dr. Stephen Forman, chairman of the Division of Hematology & Hematopoietic Cell Transplantation at the City of Hope Comprehensive Cancer Center in Duarte, Calif., who wasn’t part of the study. “The fact that you got somebody insulin-independent, there’s a clue there” for scientists in search of a cure.
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.
Most of those patients will die from complications of the disease rather than diabetes itself. The age of onset is considerably younger than for patients with Type-2 diabetes, 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. Bone marrow contains hematopoietic stem cells, which are able to build all the elements of the immune system. The idea is to wipe out the faulty immune system and replace it with a new one that functions properly.
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 a period of 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.
Patients who were diagnosed with Type-1 diabetes long ago would not benefit from a stem-cell transplant because their immune systems have left nothing to preserve, said Dr. Jay Skyler, associate director of the Diabetes Research Institute at the University of Miami Miller School of Medicine, who wrote an editorial accompanying the study.