Clustering of replicating cells in aortic endothelium

Abstract

Endothelial cells are lost into the blood stream in human beings. From animal studies, it is known that endothelial cells can multiply, as indicated by autoradiography and by the regeneration of endothelium following partial denudation of the aorta in experimental animals. The rate of aortic endothelial cell replication under normal conditions has been studied in several species and has been estimated to be less than 1% per day. This low rate of incorporation has been taken to mean that the rate of cell turnover is low. This, however, assumes that cell loss and cell replication are uniformly and randomly distributed over the inner surface of the vessel. Cell division in the aortic endothelium of the rat is not randomly distributed. Maps of the aortic surface show focal areas where the daily rate of replication may be in excess of 50%. This implies the existence of focal areas of rapid cell growth or rapid cell turnover and other areas where growth or turnover is largely absent.