Vascular endothelial growth factor (VEGF), also called vascular permeability factor (VPF), is a specific type of protein known as a signal protein that encourages the body’s creation of blood vessels. When cells release this protein, it “signals” the body to take action — in the case of VEGF, either by angiogenesis or vasculogenesis. Angiogenesis is the creation of new blood vessels from existing vasculature, while vasculogenesis is the creation of the circulatory system in the embryo. The vascular endothelial growth factor protein is critical to human survival as it’s the protein that restores the supply of oxygen to tissues that have become hypoxic, or suffered a loss of oxygen. Most often, this occurs after cells become injured or to repair muscle after exercise. However, VEGF expression can also result in the formation of new blood vessels to circumvent ones that are blocked, a process called collateral circulation. Overexpression of VEGF can lead to disease.