Endothelial injury and repair: a novel theory for atherosclerosis.

The traditional view of atherosclerosis as a pathological lipid deposition within the artery wall has been redefined by a more complex theory in which the presence of a dysfunctional endothelium plays a pivotal role. The discovery of progenitor cells of myeloid origin, which are able to replace old or injured mature endothelial cells and are able to differentiate into healthy and functional endothelial cells, has offered the prospect of merging the traditional theories on the pathogenesis of atherosclerosis with the evolving concept of a role of these progenitor cells in the repair of the injured vessel wall and the neovascularization of ischemic tissues. This article summarizes current knowledge about the biology of atherosclerosis with emphasis on the balance between endothelial injury and repair and on the concept that the turnover and replacement of endothelial cells is a major determinant in the maintenance of vascular integrity.