THE INSIDE STORY on coronary artery disease has come to center on the role of the endothelium. Various hypotheses have been advanced in the past concerning what might ensue, for example, after damage to the blood vessels' lining. At the most recent Scientific Sessions of the American Heart Association (AHA) held in New Orleans, La, several presentations showed that endothelial dysfunction, whatever its cause, appears to play an important role as a harbinger of atherosclerosis and subsequent adverse coronary events.
Evidence from experimental and clinical investigation points toward three major mechanisms of action by which the blood vessels' cellular lining, because of its unique position between the blood and the vessel wall, may influence the development of lesions in the coronary arteries. It may do so, say researchers, by causing altered vasomotor responses, by promoting increased growth of other blood vessel elements such as smooth-muscle cells, or by predisposing to