Evidence is accumulating that the best treatment for Type 2 diabetes related to obesity may well be the most drastic: stomach-shrinking surgery, perhaps accompanied by intestinal rearrangements. That such extreme remedies would even be considered is a measure of how intractable the intertwined epidemics of obesity and diabetes have become in the United States.
Diabetes of all types is a vicious disease that kills some 73,000 Americans each year, making it the fifth-leading cause of death in this country. It is characterized by an inability to produce or use insulin, with the result that blood glucose levels soar, damaging the kidneys, blood vessels in the eyes and nerves in the feet.
There is no cure, only the hope that it can be controlled by strict dieting, drugs and a lifetime of careful living. Unfortunately, many patients are unable to comply with the onerous regimen, pounds lost are ultimately regained and legions of patients suffer heart attacks, blindness, kidney failure or foot amputations.
Against that discouraging backdrop, a new study by Australian researchers, published in the Journal of the American Medical Association, seems to promise extraordinary results, albeit with many caveats about the preliminary nature of the findings in a relatively small group of patients who had mild cases of the disease.
The study involved 60 patients who were obese and had recently developed Type 2 diabetes, by far the most prevalent kind. Half were given conventional treatments, including diet, exercise and medicines. The rest got conventional treatment plus surgery in which a band is placed around the stomach to constrict its size and limit eating.
In almost three-quarters of those who had surgery, all signs of diabetes disappeared. Only 13 percent of those given conventional therapy had complete remissions. The difference was because of weight loss. Patients in the medically treated group lost only 1.7 percent of their weight, on average. Those in the surgically treated group lost 20.7 percent. There were no serious complications from the minimally invasive procedure.
Other studies have shown that gastric bypass surgery, a riskier operation in which the stomach is stapled and the intestinal tract rearranged, is even more effective, achieving remission in a matter of days or weeks, well before substantial weight loss has occurred. This is apparently because the operation causes metabolic changes that lower blood glucose levels beyond what weight loss alone can accomplish.
Some experts predict that surgery will become a common treatment for diabetes in coming years. Before that happens, it will be essential to see how patients fare over an extended period and get a better fix on which patients are most likely to benefit from costly surgeries that always bear some risk.
Source: nytimes
Wednesday, February 20, 2008
Surgical Treatment for Diabetes
Stem Cell Therapy Controls Diabetes in Mice
Scientists reported Wednesday that they were able to control diabetes in mice by harnessing human embryonic stem cells. The work raised the prospect that the embryonic cells might one day be used to provide insulin-producing replacement cells to treat the disease in people.
The scientists, at the biotechnology company Novocell, turned the stem cells into cells that produced insulin in the mice. Those cells kept blood sugar in check after the mice’s own insulin-producing cells were destroyed.
“For those who say there is not much evidence that embryonic stem cells can cure diabetes, there you go,” said Dr. Camillo Ricordi, director of the diabetes research institute at the University of Miami, who was not involved in the research.
Still, a small number of the mice developed tumors, and some experts said the cells might not be well characterized enough for use in people. In any event, Novocell said it would be several years before any human tests could begin.
Doctors are already experimenting with transplants of insulin-producing islet cells from cadavers for patients with type 1 diabetes, a disease which destroys a person’s own islet cells. In some cases, the transplant recipients have not needed daily injections of insulin, at least for a while.
But there are too few donors to provide cell replacement to more than a small percentage of diabetics. Embryonic stem cells, which can potentially be turned into any type of cell in the body, could potentially be a source of islet cells.
Novocell, which is based in San Diego, reported in 2006 that they had turned human embryonic stem cells into insulin-producing cells in culture dishes, something others have also reported doing. But Novocell’s cells did not vary insulin production in response to glucose, a key requirement for implantation.
In the latest work, published online Wednesday by Nature Biotechnology, the researchers got assistance from the mice themselves. Instead of implanting the insulin-producing cells into mice, they implanted precursor cells that were one step short of developing into insulin-producing cells.
The mice’s bodies apparently provided the proper signals to turn the implanted cells into functioning insulin-producing cells in about 90 days.
When the scientists used a toxin to destroy the mice’s own islet cells, the animals that had received the human cells continued to produce insulin and control their blood sugar while mice without the implants quickly became diabetic. After about 100 days, the scientists then removed the implanted cells from the mice that had them, and blood sugar levels shot up.
“This for the first time validates that you can use human embryonic stem cells to produce fully functional human islets,” said Emmanuel E. Baetge, the chief scientific officer of Novocell and senior author of the report.
But Dr. Mark A Magnuson, a professor at Vanderbilt University and director of its stem cell biology center, said the Food and Drug Administration might not allow the transplant into people of cellular material that would have to “mature” in the body.
“Would this happen reproducibly in different people, and would it be the same in all transplant sites?” Dr. Magnuson said in an e-mail message. “If it wasn’t totally predictable, could there be adverse effects, such as tumors?”
Indeed, in the Novocell experiment, 7 of the 105 mice with the implants developed teratomas, a sort of tumor. Dr. Baetje said Novocell probably could have reduced or eliminated the teratomas if it had purified the cells before implanting them.
Dr. Ricordi of the University of Miami said he was somewhat concerned by signs that the implanted cells cut glucose levels too much, which itself can be dangerous.
This article written by Andrew Pollack, published at nytimes
