A Preliminary Study Shows Stem Cells Fight Diabetes
Adult stem cells transplanted into people with type 1-diabetes show potential as a treatment, according to a preliminary study in the current issue of the Journal of the American Medical Association. "It's a very promising step forward, but I would never use the word cure," says Richard Burt, the director of the department of immunotherapy at Northwestern University and one of the study's authors.
Of the study's 15 participants, 14 were able to go off insulin injections after undergoing powerful chemotherapy followed by the infusion of their own stem cells. But Burt cautions that it's way too early for patients to get excited: One of the 14 has relapsed, and others could. In addition, complications from the procedure can cause death in about 1 in 200 people, he estimates, raising questions about whether the benefits outweigh the risks of the treatment, especially among children.
Type 1-diabetes occurs when the immune system mistakenly attacks and destroys insulin-producing beta cells, requiring diabetics to take daily doses of insulin to clear glucose from their bloodstream. Burt, who specializes in adult stem cell transplants for autoimmune diseases like multiple sclerosis and lupus, thought that by extracting stem cells from the blood, performing chemotherapy to kill the defective immune cells, and then reintroducing the stem cells into the same person, he might be able to reset the immune system. (The team did not use the controversial stem cells that come from human embryos.)
"We got the results we wanted, so I was very pleasantly surprised," says Burt. During the seven-to-36-month follow-up, one person has gone medication free for 35 months, four people for 21 months, and seven for six months. Two people didn't respond immediately to the treatment but have been insulin free for one and five months. All the study participants experienced adverse effects from the chemotherapy such as loss of appetite, fever, skin rashes, and diarrhea. One person contracted pneumonia and two others experienced endocrine dysfunction.
"It's theoretically a very promising approach, but I'd like to see a bigger, longer, more rigorous study before drawing conclusions," says Jay Skyler, a diabetes researcher at the University of Miami and the author of an editorial accompanying the study in JAMA. In the editorial, he points out a number of areas that need to be addressed in future research, including the need for a randomized control group. Defu Zeng, a diabetes researcher at the Beckman Research Institute at City of Hope medical center in California who's conducted similar experiments on diabetic mice, has reservations as well. In his experiments, diabetes always returned after a period of remission. "We should observe for at least five or six years to be sure," he says.
"The next step is to do a randomized trial of adults in the United States," says Burt.