The fat cells that surround coronary arteries may play a central and previously unrecognized role in development of cardiovascular disease, according to a study by University of Iowa researchers.
Dr. Lynn Stoll presented the research team's findings at Experimental Biology 2006 in San Francisco. Her presentation was part of the scientific program of the American Society of Investigative Pathology.
Once thought of as mere storage depots for excess energy, fat cells ("adipocytes") are now known to be highly active metabolically, releasing potent pro-inflammatory proteins and hormones that regulate inflammation, blood pressure, insulin activity, and other biological processes. Where fat cells are located has a major influence on their impact, as seen in the fact that visceral fat surrounding the internal organs ("apple" body shape) is far more highly correlated with development of diabetes and cardiovascular disease than subcutaneous fat in the thighs and buttocks (pear" body shape).
One area of adipose tissue that has received little attention is the perivascular adipose tissue that envelops most large blood vessels in humans. The function of these fat cells is largely unknown, but the fact that the coronary arteries are embedded in fat tissue led the Iowa researchers to believe that these fat cells have a direct role in the pathogenesis of the atherosclerosis to which these arteries are so highly susceptible.
The research team, led by Dr. Stoll and senior investigator Dr. Neal Weintraub, isolated and cultured adipocytes from the fat tissue surrounding human coronary arteries and, for comparison, cells from other fat tissue including subcutaneous fat. Their experiments showed three important differences in how the fat cells from around the coronary arteries (the epicardial adipocytes) function compared to fat from other areas of the body: