title: Macrophage-induced angiogenesis is mediated by tumour necrosis factor-alpha.
abstract: Macrophages are important in the induction of new blood vessel growth during wound repair, inflammation and tumour growth. We show here that tumour necrosis factor-alpha (TNF-alpha), a secretory product of activated macrophages that is believed to mediate tumour cytotoxicity, is a potent inducer of new blood vessel growth (angiogenesis). In vivo, TNF-alpha induces capillary blood vessel formation in the rat cornea and the developing chick chorioallantoic membrane at very low doses. In vitro, TNF-alpha stimulates chemotaxis of bovine adrenal capillary endothelial cells and induces cultures of these cells grown on type-1 collagen gels to form capillary-tube-like structures. The angiogenic activity produced by activated murine peritoneal macrophages is completely neutralized by a polyclonal antibody to TNF-alpha, suggesting immunological features are common to TNF-alpha and the protein responsible for macrophage-derived angiogenic activity. In inflammation and wound repair, TNF-alpha could augment repair by stimulating new blood vessel growth; in tumours, TNF-alpha might both stimulate tumour development by promoting vessel growth and participate in tumour destruction by direct cytotoxicity.
mesh_terms: D000818:Animals; D003315:Cornea / Q000098:blood supply; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D008264:Macrophages / Q000502:physiology*; D008833:Microcirculation; D009389:Neovascularization, Pathologic; D051381:Rats; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D005346:Fibroblast Growth Factors