Angiogenic Activity and Hypoxia Regulation
نویسندگان
چکیده
To investigate the in vivo angiogenic activity of placenta growth factor (PlGF) and its heterodimers with vascular endothelial growth factor (VEGF), the induction of neovascularization of these factors in the mouse cornea was studied. VEGF 165 is sufficiently potent to stimulate new capillary growth from the limbal vessels. PlGF 129 /VEGF 165 heterodimers also induce corneal neovascularization with a maximal vessel length similar to VEGF 165 , but with a marked decrease of vessel density. In contrast, PlGF 129 has little or no effect in this in vivo angiogenesis assay. The expression of VEGF mRNA and protein is drastically up-regulated by hypoxia in choriocarcinoma cells, whereas expression of PlGF is not affected by the low concentration of oxygen. Up-regulation of VEGF production results in increased formation of PlGF/VEGF heterodimers in these tumor cells. Thus, hypoxia indirectly up-regulates expression levels of PlGF/ VEGF heterodimers and modulates VEGF activity when these factors are co-expressed. ( J. Clin. Invest. 1996. 98: 2507-2511)
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