HOUSTON, April 20 (UPI) -- A new gene therapy has been found to temporarily cure mice of diabetes by triggering cells in the liver to produce insulin and other hormones, according to a new study released Sunday.
Researchers led by Dr. Lawrence Chan, a professor of medicine and molecular and cellular biology and also the chief of the division of diabetes, endocrinology and metabolism at Baylor College of Medicine in Houston, Tex. said this new treatment offers a great deal of promise in managing a chronic illness that afflicts millions worldwide and is one of the most common diseases in the United States.
"We have broken the barrier of the concept that you can turn one type of cells into another type of cells in the body," Chan told United Press International. "I think that's a pretty important proof of principle.
Chan and colleagues used a gene called NeuroD to get the liver to produce beta cells to make insulin and other hormones, glucagon, somostatin and pancreatic polypeptide, which may play a role in regulating insulin production and release. To inject the gene, researchers used an adenovirus, which causes many respiratory infections in humans, as a transportation device for the gene. The toxic DNA of this adenovirus was removed so that it would not cause illness.
Once this gene reached the liver cells, the cells evolved into beta cells and initiated insulin production. The mice were cured of their diabetes entirely for up to four months, researchers report in the April 20 online edition of Nature Medicine.
"The idea is to replace insulin," Chan said. "The beta cells are very smart. They sense the high glucose," that occurs during diabetes, "and they have a burst of insulin."
Although the pancreas produces insulin, he explained, "we used the liver because of its accessibility, ...secondly, the liver is almost as good as the pancreas, so therefore it's a very reasonable site."
The advantage this treatment has over others is that it does not require powerful, and potentially dangerous drugs to prevent the immune system from attacking foreign cells used in cell transplants. Instead, this approach boosts the body to use its own cells. Also, because this treatment doesn't use donor cells, it eliminates the challenge of finding a matching cell type from a donor.
However, this "cure" is temporary and would require repeated injections, researchers point out. Also, just because this worked very well in mice does not guarantee such effects in people. "Unfortunately, it will probably take years," before such a treatment would be available to diabetes patients, Chan said. "Like any other gene therapy, the major concern is safety. People are quite different than mice.
Dr. Eugene Barrett, the president-elect of the American Diabetes Association and a professor of medicine at the University of Virginia in Charlottesville, Va. told UPI, this study was "a ground-breaking piece of work."
"To make (cells) respond to glucose is a complicated process," Barrett said. "They've been able to get cells to differentiate more like beta cells. So I thought it was very clever. I think it's a very interesting, potentially important study."
(Reported by Katrina Woznicki, UPI Science News, in Washington)