VEGF, or vascular endothelial growth factor, is a cell protein produced by the body. The protein binds to cells and encourages certain cell activity. Creation and repair of blood vessel networks is perhaps the protein's most important function. It also serves a major role in keeping the body’s tissues supplied with adequate amounts of oxygen. Despite its positive contributions, an overabundance of the protein can cause adverse health consequences.
Vascular endothelial growth factor creates and strengthens blood structures. Cells lining the inside of blood vessels — or endothelial cells — contain the protein. It promotes the repair of damaged vessels and also creates new smaller vessels, a process known as angiogenesis. For example, when skin or another surface ruptures, VEGF is produced at the rims of the wound. The encouragement of new vessel development helps facilitate wound healing.
The protein also helps in vasculogenesis, or the creation of the circulatory system. During the initial period of embryo development, vascular endothelial growth factor is used to help generate blood vessels. These vessels will eventually comprise the body's vascular circulatory network, or the body's avenue of blood flow. In this process, some cells in the bone marrow become endothelial cells, which in turn produce the vascular protein and other substances important in blood vessel creation.
Several types of vascular endothelial growth factor exist. VEGF-A is important in angiogenesis. Both VEGF-B and a form called placental growth factor (PGF) play major roles in the formation of blood vessels in embryos. While most types are thus concerned with blood vessel development, other structures may be impacted as well. For example, VEGF-C aids in lymphatic vessel creation, whereas type VEGF-D helps encourage development of blood and oxygen supply structures around the lungs.
Oxygen supplementation is another key function of vascular endothelial growth. When the body’s tissues are deprived of oxygen, cells produce a substance called hypoxia-inducible factor (HIF). This substance encourages more VEGF protein production, which helps alleviate the oxygen deprivation.
Due to its impact on blood, however, excessive vascular endothelial growth factor can create conditions for some diseases. For example, the blood vessels of the eye are very delicate. The protein can cause uncontrolled and aggressive changes in these structures, particularly in the retina. It can also feed cancers by giving them a blood supply to promote their spread.
Some forms of cancer therapy called anti-VEGF treatment target production of the protein. Lowered protein levels may curb metastasis, or the spread of a cancer. An anti-VEGF drug known as bevacizumab has shown positive results with some patients.