Molecular bases of angiogenesis

Abstract

Angiogenesis is a multistep process that drives the formation of new blood capillaries from the pre-existing vasculature. It is usual to distinguish two phases in this process: a morphogenic phase that requires endothelial cell proliferation and migration followed by a maturation phase characterized by the reconstitution of extracellular matrix and the recruitment of pericytes around the newly formed microvessel. Angiogenesis is actively involved in embryonic organogenesis as well as in cancer tumor growth. Although the properties of neovessels formed under these two situations are different, the molecules and the mechanisms implicated are common. VEGF and its receptors flk-1 and flt-1 are the main actors of the morphogenic phase whereas PDGF-BB and its receptor PDGF-R beta, TGF beta 1 and its receptors ALK-5 and ALK-1, angiopoietin-1 and its receptor tie-2 are implied in the vascular maturation phase.