Endothelial Dysfunction as a Target for Prevention of Cardiovascular Disease

The endothelium, once considered amere selectively permeable barrierbetween the bloodstream and the outer vascular wall, is now recognized to be a crucial homeostatic organ, funda-mental for the regulation of the vascular tone and structure. Indeed, endothelial cells are able to synthesize and secrete a broad spectrum of anti-atherosclerotic substances, the most characterized of which is nitric oxide (NO), a gas that is generated from the metabolism of L-arginine by endothelial NO synthase (eNOS), constitutively expressed in endo-thelial cells (1). Under physiologic condi-tions, endothelial stimulation induces the production and release of NO, which dif