FIGURE 1.

Vasculogenesis and angiogenesis are the main processes responsible for vascular remodeling. (A) Schematic representation of vasculogenesis, which consists in de novo aggregation of circulating endothelial progenitor cells (EPCs) into functional vessels. (B) Schematic representation of angiogenesis, the physiological process whereby capillaries give rise to neovessels to cope with oxygen and nutrient requirements. Angiogenesis may occur through two distinct mechanisms: sprouting angiogenesis and intussusceptive angiogenesis (see text for further details).