Figure 1: Embryonic versus adult vasculogenesis. During embryonic vascular development, endothelial cells (EC) derived from angioblast precursors migrate to regions of neovessel formation. Additionally, mesenchymal stem cells (MSCs) differentiate into pericytes which support and guide the development of endothelial cells. In adult tissues, vasculogenesis proceeds via recruitment of endothelial progenitor cells (EPCs) to neovessels. Supporting pericytes are thought to be derived from local fibroblasts or bone-marrow-derived mesenchymal cells. These complex interactions are mediated by cytokine networks responsible for creating functional three-dimensional vascular systems during development and throughout life.