An example for this matrix approach is the measure of i) IL-1RA secretion in response to stimulation by M1-polarized macrophages, ii) pro-angiogenic VEGF secretion after 48h hypoxia, and iii) tube formation of hMSCs on matrigel as potency test matrix for ABCB5+ skin-derived hMSCs for treatment of chronic venous ulcers, epidermolysis bullosa, and liver disease (67). The gene discussed is VEGFA; the disease is epidermolysis bullosa.