Senescence stimulates U937-endothelial cell interactions.

Progressive pathophysiologic modifications of endothelial cells are associated with aging. In vitro, endothelial cell senescence is accompanied by the failure to proliferate as well as by perturbations in gene expression. Here we show that (i) senescence enhances monoblastoid U937 cell adhesion to the endothelial monolayer; (ii) the enhanced interaction between senescent endothelial cells and U937 cells is mediated, at least in part, by the overexpression of ICAM-1; and (iii) LPS and interleukin 1 alpha, but not tumor necrosis factor alpha, are unable to stimulate the adhesion of U937 to senescent endothelial cells. Since monocyte adhesion to the endothelium is an early event in atherosclerosis, the altered adhesive properties observed in senescent cells could give insights into the formation of atherosclerotic lesions.