Stem cells transplanted into young adults diagnosed with Type 1 diabetes held the disease at bay and freed most patients from insulin shots for an average of 31 months, researchers said.
The findings came from an extension of a 2007 study by a Brazilian team, expanded to 23 young adults with newly diagnosed Type 1 diabetes. Twenty patients given the stem-cell treatment were able to stop insulin injections as tests showed their bodies took over production of the hormone.
The study is part of a broad-based push to cure diabetes by a variety of treatments, including whole-organ transplants of the pancreas, islet-cell transplants and stem-cell transplants, along with making tools for managing the disease more effective for patients. Over years, diabetes can cause cardiovascular disease, blindness, kidney failure and nerve damage.
The stem-cell technique "remains the only treatment capable of reversing Type 1 diabetes mellitus in humans," wrote the paper's senior author, Julio Voltarelli, and colleagues at the University of Sao Paulo and in the United States. The work was reported online yesterday in the Journal of the American Medical Association.
Co-authors said the extended study refuted the skepticism that greeted the initial research report. "The criticism before was that maybe this was some honeymoon period from prolonged observation," Richard Burt, chief of the division of immunotherapy at Northwestern University's Feinberg School of Medicine, said in an interview.
Proof that the treatment worked came from measuring patients' levels of C-peptide, Dr. Burt said, because that substance reflects activity in the body's cells critical to making insulin. The study found that C-peptide increased in most patients over time, and even normalized at three years.
"It's clearly not a honeymoon effect, but insulin production from the pancreas," Dr. Burt said.
While 20 of the 23 patients were able to stop insulin shots, over time eight patients relapsed, requiring them to return to low-dose insulin injections, and three didn't respond.
"A cure is needed, but it will probably not come from a single breakthrough," wrote Christopher Saudek of Johns Hopkins University in Baltimore in an accompanying editorial. "More likely, the cure will be a gradual process building over years. Biological approaches will improve incrementally with the procedures becoming more effective with fewer adverse effects."
An estimated 246 million people worldwide are affected by diabetes, according to the Canadian Diabetes Association. Between 5 per cent and 10 per cent have Type 1, a condition in which the body's immune system attacks pan- creatic cells that produce insulin, the hormone that enables the body to use sugar
for energy. Most diabetics
have Type 2, an illness linked to obesity and resistance to
insulin.
Major complications of the stem-cell treatment included pneumonia in two patients, low sperm counts in nine men and endocrine dysfunction in three, the researchers reported.
The earlier study in 2007 reported on 15 patients who first received chemotherapy to damp down their overactive immune systems, followed by injection of stem cells isolated from their own blood. They were followed for almost 19 months, a period in which most were able to stop insulin injections.
In the current study, researchers added five patients to the original group, enlarging it to 23 volunteers aged 13 to 31 receiving the same treatment. They were observed for a longer period, and underwent C-peptide tests to monitor their bodies' own insulin production.
"Two years ago I said this was an interesting first step," said Jay Skyler, professor of medicine and associate director of the Diabetes Research Institute at the University of Miami. "The problem is that the new paper doesn't add new insights. I was disappointed."
Long-term freedom from the need for insulin injections shows the technique is worth testing in a controlled clinical trial, Dr. Skyler added.
Dr. Burt said plans are under way for such a test, comparing stem-cell transplants with intensive insulin injection therapy. Study plans approved by Northwestern's institutional review board now await a green light from the U.S. Food and Drug Administration, he added.
"I started work on stem cells for autoimmune disease 20 years ago," Dr. Burt said. "We work 24/7, and we're getting there as fast as we can. It's now in the hands of the FDA."
