VEGFA and ischemia: While the primary mechanism of ischemia-induced angiogenesis involves the production of hypoxia-inducible factor-1α (HIF-1 α) protein, and the consequent increase of expression of vascular endothelial growth factor (VEGF) (4), it has been shown that immune system also plays a pivotal role in modulating ischemia-induced hindlimb angiogenesis (5–8).