[The role of the endothelium in angiogenesis]

Angiogenesis, the vessel formation process, happens both in normal and pathological conditions, beginning with embryonic period and continuing throughout the post-natal period during the whole life. The stimulating factors of angiogenesis are enumerated: VEGF (vascular endothelial growth factor), PLGF (placental growth factor), IF (Intherpheron gamma), Il1, Il8 (interleukin 1,8), FGF (fibroblast growth factor), acid and basic, TGF (transforming growth factor), PDGF (platelet derived growth factor), GH (growth hormone). A series of factors act as regulators/modulators: hypoxia, PGE1, (prostaglandin E1), gangliosides, heparin, cell-cell and cell-substrate interactions. The main inhibitors are less numerous: trombospondin1, PF4 (platelet factor 4), TNF (tumor necrosis factor), IF (interferon alpha). The implied mechanism are discussed: the ways, paths and action phases of different stimulating factors, modulating or inhibiting factors. The angiogenesis process is shown for the embryonic period, in the wound healing process and in the development and progression of malignant tumors. The main method employed in the study of the microvasculature are enumerated. Some perspective in the cancer treatment are drafted.