Angiogenesis and endothelial cell function.
Endothelial cell growth is tightly regulated. During embryonic development endothelial cells rapidly proliferate thereby forming new blood vessels. Two different mechanisms contribute to the development of the vascular system: vasculogenesis, the development of blood vessels from in situ differentiating endothelial cells, and angiogenesis, the formation of capillaries from preexisting vessels. In the adult, endothelial cell turnover is very low but under a variety of pathological conditions such as tumor growth these cells quickly enter the cell cycle and divide. Vascular endothelial growth factor (VEGF) has been identified as a key regulatory paracrine growth factor for endothelial cells. Transient VEGF expression correlates with embryonic and tumor angiogenesis. On the other hand, constitutive expression of this factor in choroid plexus and kidney glomerular epithelium and its cognate receptors in adjacent fenestrated endothelium suggests a role for this ligand-receptor system in organotypic endothelial cell differentiation and capillary permeability of fenestrated endothelium.
Risau
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Abteilung Molekulare Zellbiologie, Max-Planck-Institut für physiologische und klinische Forschung, W. G. Kerckhoff-Institut, Bad Nauheim, Fed. Rep. of Germany.
D000818:Animals; D004730:Endothelium, Vascular / Q000166:cytology / Q000503:physiopathology*; D006801:Humans; D009389:Neovascularization, Pathologic / Q000503:physiopathology*