Hypoxic induction of vascular endothelial growth factor (VEGF) protein in astroglial cultures.

Vascular endothelial growth factor (VEGF) couples hypoxia to angiogenesis in ischemic tissues, including brain. Since hypoxia induces VEGF mRNA in astroglial cultures, we examined its effect on VEGF protein, measured by ELISA, in medium from cultures exposed to 95% N2/5% CO2 for up to 24 h. Levels increased with increasing durations of hypoxia, but not glucose deprivation, reaching approximately 30-fold elevation by 24 h. Co2+ and desferrioxamine also increased VEGF levels, while inhibitors of RNA or protein synthesis blocked induction. These findings support a role for astroglia in the hypoxic induction of VEGF expression and release-and potentially angiogenesis-in the ischemic brain.