Optical images of endothelial differentiation of ADSCs induced by 3-day (A, C, E, G) and 11-day treatment (B, D, F, H) with VEGF-A and shear stress. Vehicle-treated ADSCs (A, B), ADSCs treated with VEGF-A (C, D), shear stress (E, F), or with VEGF-A under shear stress (G, H). White arrows indicate cord-like formation induced by shear stress in the absence (F) or presence of VEGF-A (H). Scale bar = 100 μm.