In vitro endothelial spheroid sprouting assay for angiogenesis

This method evaluates sprouting propensity of endothelial cells in a collagen matrix. The effect of pro-angiogenic growth factors or co-cultured cells can be measured by quantifying the amount of vascular sprouts that form on endothelial spheroids. Endothelial spheroids are obtained by growing endothelial cells in hanging drops, which forces the cells to adhere to each other. The peripheral cells acquire a flat phenotype, similar to the flattened endothelial wall of blood vessels. After generation of the spheroids, they are embedded in a collagen matrix in which endothelial growth factors or specific cell types can be embedded. Finally the amount of endothelial sprouts is quantified as a measure of the endothelial sprouting propensity.