VEGFA and ischemia: EPCs promote angiogenesis or vascular repair through activation of resident endothelial cells and recruitment of endogenous monocytes/macrophages to sites of ischemia, which were mediated by paracrine factors [26] such as vascular endothelial growth factor (VEGF) [27–29], granulocyte-macrophage colony-stimulating factor (GM-CSF) [29–32], and nitric oxide (NO) [32–34].