March 2004 - The rise in obesity, now at epidemic levels in the United States, has been matched by a rise in diabetes, a deadly combination that increases heart disease risk by two to five times. Research has shown an association between obesity, insulin resistance and diabetes, and it's believed that insulin resistance plays an important role in the development of heart disease. Experts are just now beginning to understand how these conditions are linked.
With the support of a $1.9 million grant from the National Institutes of Health, Temple University diabetes expert Guenther Boden, M.D., will examine how obesity-associated diabetes leads to cardiovascular disease, in hopes of ultimately breaking this dangerous progression.
Common among all obese people to varying degrees, insulin resistance prevents insulin from performing its job, which is to take the sugar from food and distribute it throughout the body for energy.
"Up to 80 percent of obese people compensate for their insulin resistance by oversecreting insulin and therefore don't become diabetic. In the remaining 15-20 percent, however, the pancreas is unable to compensate for insulin resistance and they become diabetic," says Boden, a Laura H. Carnell professor of medicine and chief of the division of endocrinology/diabetes/metabolism at Temple University School of Medicine.
"Over the years, we've determined that a major link between obesity and insulin resistance is a high level of free fatty acids," Boden says. "When the levels of free fatty acids circulating in the blood stream are too high, which is usually the case in obesity, they cause insulin resistance and seem to simultaneously set off inflammation. Inflammation may provide the missing link to heart disease." The researchers will examine the inflammatory process, particularly what triggers it and what inhibits it. Previously, they demonstrated that in lean people, elevated free fatty acids cause insulin resistance and start the pro-inflammatory processes, which can in turn lead to heart disease. Now they will examine this phenomenon in more detail in obese patients.
"This is an exciting area of research. Cardiovascular disease is, to a large extent, an inflammatory process. For the first time, we're starting to understand why it is that being obese, diabetic and insulin resistant increases risk of atherosclerotic disease two-to-five-fold. Through our research, we will look for the mechanisms involved. We hope that the knowledge we gain will help in preventing and treating heart disease in the many millions of obese patients with diabetes," explains Boden.
Other researchers on the team include Carol Homko, RN, Ph.D.; Peter Cheung, Ph.D.; Erik Murer, Ph.D.; Maria Polansky, Sc.D.; and Dorota Walewicz, M.D.
Source: Temple University