TUESDAY, April 10, 2007 (HealthDay News) -- A pilot study of people newly diagnosed with type 1 diabetes found that stem cell therapy eliminated the need for insulin therapy for varying periods of time.
This is the first trial to look at stem cell therapy in humans with this form of the disease. But experts stressed that the research is preliminary and urged caution when interpreting the results, which are published in the April 11 issue of the Journal of the American Medical Association.
"This may be the first step in something that could be promising, but I need to see a control group and longer follow-up before I'd go out on a limb," said Dr. Jay S. Skyler, author of an accompanying editorial in the journal and associate director of the Diabetes Research Institute at the University of Miami Miller School of Medicine. "But this is worthy of further experimentation."
Type 1 diabetes develops when the body's immune system attacks the pancreatic beta cells, which produce insulin -- the hormone that transports sugar from the blood to cells for energy.
"In type 1 diabetes, the immune system is out of balance," Skyler explained. "Ordinarily, all of us have some cells with the potential to destroy the pancreas, but the regulatory immune system prevents those cells from becoming sufficiently active. In type 1 (diabetes), there's a greater proportion of activity of the destroying cells and lesser activity of the regulatory cells. The goal is to try to bring that back into balance."
By the time a person is diagnosed with the disease, some 60 percent to 80 percent of the beta cells have already been destroyed. And people who have more functioning beta cells tend to have fewer complications down the line, research has shown.
Immunosuppression therapy, designed to dampen the immune system, can help, but these patients still need to take insulin to regulate their blood sugar. Meanwhile, stem cell therapy has had some success with other autoimmune diseases, such as lupus, but not with type 1 diabetes.
"There has been use of this specific procedure in other autoimmune disease in human beings with some suggestion of promise of effect, and it's been advocated for a number of years that this kind of approach might be useful in type 1 diabetes," Skyler said.
The new study, conducted by scientists in Sao Paolo, Brazil, and in Chicago, involved 15 patients newly diagnosed with type 1 diabetes. All participants underwent high-dose immunosuppression therapy followed by a procedure called autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) to preserve beta-cell function.
AHST involves removing a patient's own blood stem cells, treating them, and then returning them to the patient.
"Using bone marrow precursor cells, which are precursors of immune T-cells, is designed to reset the immune system," Skyler said. "The reason for choosing a point early in time is that you want to have enough beta cells that are still left."
During follow-up that lasted up to 36 months, 93 percent of the patients achieved some length of insulin independence. Fourteen patients became insulin free -- one for 35 months, four for at least 21 months, seven for at least six months. Two more participants who had late responses to the stem cell therapy became insulin free for one and five months, respectively.
One person developed pneumonia, and two others developed problems with their endocrine system, which governs hormones in the body.
It's unclear exactly how the stem cell transplants worked their magic. And there are still numerous questions.
"The obvious question is how long does it work and what is the risk of treatment," said Dr. Larry Deeb, president of medicine and science at the American Diabetes Association. "But the excitement is where we are in diabetes research and treatment, and the excitement some of these questions generate for people who have diabetes and for the diabetes community and for the profound argument that this is not a time to be proposing less money for research in diabetes."
Visit the American Diabetes Association for more on type 1 diabetes.