Thirteen young diabetics in Brazil have ditched their insulin shots and need no other medication thanks to a risky, but promising treatment with their own stem cells -- apparently the first time such a feat has been accomplished.

Though too early to call it a cure, the procedure has enabled the young people, who have Type I diabetes, to live insulin-free so far, some as long as three years. The treatment involves stem cell transplants from the patients' own blood.

"It's the first time in the history of Type 1 diabetes where people have gone with no treatment whatsoever ... no medications at all, with normal blood sugars," said study co-author Dr. Richard Burt of Northwestern University's medical school in Chicago.

While the procedure can be potentially life-threatening, none of the 15 patients in the study died or suffered lasting side effects. But it didn't work for two of them.

Larger, more rigorous studies are needed to determine if stem cell transplants could become standard treatment for people with the disease once called juvenile diabetes. It is less common than Type 2 diabetes, which is associated with obesity.

The hazards of stem cell transplantation also raise questions about whether the study should have included children. One patient was as young as 14.

Dr. Lainie Ross, a medical ethicist at the University of Chicago, said the researchers should have studied adults first before exposing young teens to the potential harms of stem cell transplant, which include infertility and late-onset cancers.

In addition, Ross said that the study should have had a comparison group to make sure the treatment was indeed better than standard diabetes care.

Burt, who wrote the study protocol, said the research was done in Brazil because U.S. doctors were not interested in the approach. The study was approved by ethics committees in Brazil, he said, adding that he personally believes it was appropriate to do the research in children as well as adults, as long as the Brazilian ethics panels approved.

Burt and other diabetes experts called the results an important step forward.

"It's the threshold of a very promising time for the field," said Dr. Jay Skyler of the Diabetes Research Institute at the University of Miami.

Skyler wrote an editorial in the Journal of the American Medical Association, which published the study, saying the results are likely to stimulate research that may lead to methods of preventing or reversing Type I diabetes.

"These are exciting results. They look impressive," said Dr. Gordon Weir of Joslin Diabetes Center in Boston.

Still, Weir cautioned that more studies are needed to make sure the treatment works and is safe. "It's really too early to suggest to people that this is a cure," he said.

The patients involved were ages 14 to 31 and newly diagnosed with Type 1 diabetes. An estimated 12 million to 24 million people worldwide -- including 1 to 2 million in the United States -- have this form of diabetes, which is typically diagnosed in children or young adults. An autoimmune disease, it occurs when the body attacks insulin-producing cells in the pancreas.

Insulin is needed to regulate blood sugar levels, which when too high, can lead to heart disease, blindness, nerve problems and kidney damage.

Burt said the stem cell transplant is designed to stop the body's immune attack on the pancreas.

A study published last year described a different kind of experimental transplant, using pancreas cells from donated cadavers, that enabled a few diabetics to give up insulin shots. But that requires lifelong use of anti-rejection medicine, which isn't needed by the Brazil patients since the stem cells were their own.

The 15 diabetics were treated at a bone marrow center at the University of Sao Paulo.

All were newly diagnosed, before their insulin-producing cells had been destroyed.

That timing is key, Burt said. "If you wait too long," he said, "you've exceeded the body's ability to repair itself."

The procedure involves stimulating the body to produce new stem cells and harvesting them from a blood sample. Next comes several days of high-dose chemotherapy, which virtually shuts down the immune system and prevents the reintroduced cells from being fought off by white blood cells. This requires hospitalization and potent drugs to fend off infection. Then, the harvested stem cells are injected back into the body where they can build a healthier immune system.

Patients were hospitalized for about three weeks. Many had side effects including nausea, vomiting and hair loss. One developed pneumonia, the only severe complication.

Doctors changed the drug regimen after the treatment failed in the first patient, who ended up needing more insulin than before the study. Another patient also relapsed.

The remaining 13 "live a normal life without taking insulin," said study co-author Dr. Julio Voltarelli of the University of Sao Paulo. "They all went back to their lives."

The patients enrolled in the study at different times so the length of time they've been insulin-free also differs.

Burt has had some success using the same procedure in 170 patients with other autoimmune diseases, including lupus and multiple sclerosis; one patient with an autoimmune form of blindness can now see, Burt said.

"The body has tremendous potential to repair," he said.

The study was partly funded by the Brazilian Ministry of Health, Genzyme Corp. and a maker of blood sugar monitoring products.

On the Net:

JAMA: http://jama.ama-assn.org

Juvenile Diabetes Research Foundation: http://www.jdrf.org