INTERACTION OF ENDOTHELIAL CELLS AND

Abstract: Adult bone marrow is a rich reservoir of hematopoietic and mesenchymal stem and pro-genitor cells. Mobilization and recruitment of bone marrow-derived cells to injured or ischemic tissue or tumors endorse the initiation and maintenance of angiogenic processes in the adult by incorporat-ing endothelial progenitor cells (EPC) into the de-veloping vasculature and by recruiting accessory hematopoietic cells. Recent data have now re-vealed that the origin of bone marrow-derived vas-cular cells is not restricted to endothelial cells but also includes pericytes—the perivascular support cells. Several laboratories have now reported the existence of pericyte progenitor cells, and these cells, like EPC, can be mobilized and recruited to the remodeling vasculature under ischemic condi-tions and in tumors. This review focuses on peri-cytes in vessel formation and on recent discoveries about their bone marrow origin in the adult. J