Definition
Angiogenesis is the growth of new capillaries from pre-existing blood vessels. Endothelial cells respond to signals such as vascular endothelial growth factor (VEGF), fibroblast growth factors and angiopoietins by degrading the surrounding basement membrane, migrating, proliferating and forming new tubes that mature with supporting pericytes. The process is essential in development and wound healing, and it is also exploited by tumours, which is why anti-angiogenic agents are studied in oncology. Common experimental models include endothelial tube-formation assays, the chick chorioallantoic membrane assay and matrix plug assays in rodents. Several research peptides, including BPC-157 and thymosin β4, have been investigated for angiogenic effects in animal models.