University of Iowa researchers found the cells release chemicals which can trigger inflammation. The findings, presented to the Experimental Biology 2006 conference in San Francisco, may help explain why obesity increases heart disease risk.
Fat cells - adipocytes - were once thought to do nothing other than simply store excess fat tissue. However, they are now known to be highly active, releasing many chemicals that influence biological processes within the body. The Iowa team suspected that the chemicals pumped out by the fat cells surrounding the coronary arteries might play a role in triggering heart disease by contributing to the deterioration of these vessels.
Tests showed that the epicardial adipocytes were prone to release greater amounts of potentially harmful, inflammation-producing cytokines in response to certain stimuli. They also stimulated the cells lining the arteries to begin the process of forming new vessels. And when oxygen was in short supply, this process was stepped up. The fat tissue surrounding the coronary arteries gets its blood supply directly from the vessel.
Lead researcher Dr Lynn Stoll said: "The fat cells surrounding coronary arteries may ultimately prove to be an important link between obesity, type two diabetes, and coronary artery disease, all of which are increasing at epidemic rates.
"A better understanding of how epicardial adipocytes sense and respond to inflammation and ischemia could lead to new, rationally designed therapies for heart disease."