ABSTRACT
The cardiovascular system is the first organ system to develop and reach a functional state in an embryo (1). “Vasculogenesis,” the in situ differentiation of endothelial cell precursors, and “angiogenesis,” the growth from the endothelium of existing vessels cooperate in achieving the mature vasculature (2). Recent studies have complemented this view, suggesting that incorporation of bone marrow-derived endothelial progenitor cells (EPC) into the growing vessel contributes to normal and abnormal angiogenesis (35). Blood vessel growth is also implicated in the pathogenesis of a variety of proliferative disorders, including tumors, intraocular neovascular syndromes, rheumatoid arthritis, and psoriasis (6-8).
