Scientists at the Harvard Stem Cell Institute (HSCI) have found that a specific hormone may be an effective treatment for type 1 and 2 diabetes, a metabolic illness afflicting an estimated 26 million Americans.
The identified hormone called betatrophin, causes mice to produce insulin-secreting pancreatic beta cells at up to 30 times the normal rate. The new beta cells only produce insulin when called for by the body, offering the potential for the natural regulation of insulin and a great reduction in the complications associated with diabetes, the leading medical cause of amputations and non-genetic loss of vision. The discovery represents a break through for diabetic treatment and research.
The lead researchers who discovered the hormone, HSCI co-director Doug Melton and postdoctoral fellow Peng Yi, have cautioned that much work remains to be done before it could be used as a treatment in humans.
“If this could be used in people,” said Melton, Harvard’s Xander University Professor and co-chair of the University’s Department of Stem Cell and Regenerative Biology, “it could eventually mean that instead of taking insulin injections three times a day, you might take an injection of this hormone once a week or once a month, or in the best case maybe even once a year.”
“Our idea here is relatively simple,” Melton said. “We would provide this hormone, the type 2 diabetic will make more of their own insulin-producing cells, and this will slow down, if not stop, the progression of their diabetes. I’ve never seen any treatment that causes such an enormous leap in beta cell replication.”
“We’ve done the work in mice,” Melton said, “but of course we’re not interested in curing mice of diabetes, and we now know the gene is a human gene. We’ve cloned the human gene and, moreover, we know that the hormone exists in human plasma; betatrophin definitely exists in humans.”
“I would like to tell you this discovery came from deep thinking and we knew we would find this, but it was more a bit of luck,” explained Melton, who in addition to his roles at Harvard is a Howard Hughes Medical Institute investigator. “We were just wondering what happens when an animal doesn’t have enough insulin. We were lucky to find this new gene that had largely gone unnoticed before”.
“Another hint came from studying something that people know about but don’t think much about, which is: What happens during pregnancy?” he said, “When a woman gets pregnant, her carbohydrate load, her call for insulin, can increase an enormous amount because of the weight and nutrition needs of the fetus. During pregnancy, there are more beta cells needed, and it turns out that this hormone goes up during pregnancy. We looked in pregnant mice and found that when the animal becomes pregnant this hormone is turned on to make more beta cells.”
Peng Yi, Ji-Sun Park, Douglas A. Melton. Betatrophin: A Hormone that Controls Pancreatic β Cell Proliferation. Cell, 2013; DOI: 10.1016/j.cell.2013.04.008