In Vitro Coculture Assays of Angiogenesis

During angiogenesis, endothelial cells invade into the stromal matrix: a complex, structured array of extracellular matrix proteins. This three-dimensional deformable substrate also contains a mixture of angiogenic factors as well as embedded stromal cells. Interactions between endothelial cells and the stromal tissue make complex and important contributions to the process of angiogenesis; however, the composition of the stromal matrix is hard to replicate in vitro. The coculture angiogenesis assay is a long-term assay that uses fibroblasts to secrete and condition a stromal matrix that more closely mimics tissue than a simple collagen gel. Like all in vitro assays of angiogenesis, it has both strengths and weaknesses. Here we give protocols for the two of the most useful applications of the assay: screening for regulators of angiogenesis and high-resolution imaging.