(SACRAMENTO, Calif.) Severe heart damage in people who are obese and diabetic is linked with a pancreatic hormone called amylin, UC Davis researchers have found.
In the failing hearts of patients who were obese and diabetic, the scientists discovered strings of proteins, small fibers and plaques made of amylin, the hormone that produces the feeling of being full after eating. They also showed in an animal model that amylin accumulation in the heart leads to heart muscle destruction and failure.
Published in the February 17 issue of the journal Circulation Research, the study also found amylin buildup in overweight patients who are not obese, suggesting the potentially dangerous accumulations may start before a diabetes diagnosis.
Heart failure is the number-one killer in obese and diabetic populations. Controlling the circulation of amylin hormone in the blood might lessen or prevent disabilities and deaths from heart disease, the scientists said.
"Amylin appears to be a stealth killer," said Florin Despa, an assistant professor of pharmacology at UC Davis and senior author of the study. "There is only one amylin protein for every 100 insulin proteins in the blood, so it has been under the radar until recently."
In healthy people, amylin circulates in the blood together with insulin --the hormone that controls carbohydrate and fat metabolism -- and principally regulates gastric fluxes and the sensation of satiety.
In studies of both normal and failing donated hearts of people undergoing heart-transplant surgery, the researchers found little or no amylin accumulation in lean people. But a quite different picture emerged from examinations of heart tissue of obese and type 2 diabetic patients. In failing hearts of these patients, they found extensive accumulation of amylin in strings of 10 to 20 proteins called oligomers. They detected a smaller but still abnormal buildup in nonfailing hearts from
|Contact: Karen Finney|
University of California - Davis Health System