In a permanent MCAO mouse model, a substantial increase of newly formed vessels was observed at the ischemia penumbra 48–72 h after the occlusion, which was related to the robust increase of VEGF and VEGF receptors (VEGFR) mediated by HIF-1 and HIF-2, suggesting the regulatory function of HIFs in the VEGF/VEGFR system during the acute phase of stroke (30). This evidence concerns the gene VEGFA and ischemia.