Angiogenesis involves the formation of capillaries from preexisting microvessels and therefore contributes to vascular remodeling and maturation. It plays a pivotal function in a variety of normal and pathological conditions such as embryonic development, the menstrual cycle, hair cycle, wound healing, arthritis, psoriasis, proliferative diabetic retinopathy, atherosclerosis, post ischemic vascularization of the myocardium and tumor growth and metastasis. The initiation of the physiopathological angiogenic response, known as the ‘angiogenic switch’, depends on the dynamic balance between exogenous or endogenous stimuli (pro-angiogenic factors) and inhibitors (anti-angiogenic factors) acting in the immediate environment of endothelial cells.
The in vitro assay proposed below consists in a co-culture model of normal human endothelial cells with normal human dermal fibroblasts. After several days of incubation, the treatment of the co-culture with the pro-angiogenic factor VEGF results in the organization of endothelial cells in pseudotubes. Therefore, under VEGF-stimulated condition, this model is suitable to evaluate test compounds capable of inhibiting the formation of this pseudotube network. The pseudotube formation in this model is analyzed by image analysis further to the specific immunolabelling of endothelial cells only using an anti-VWF antibody.
Remark : Under basal conditions (in absence of VEGF), this co-culture model can also be used to screen compounds capable of promoting the development of the pseudotube (assay ENDOF-0001).