Additive effect of rh-sCD146 and VEGF on angiogenic capacity of EPCs in vitro. (A) Proliferation capacity of late EPCs was evaluated when rh-sCD146 (50 ng/mL) and VEGF (20 ng/mL) were added together and compared with the effect of each growth factor added separately. Results are the mean ± SEM values of 4 different experiments. (B) Migration capacity of late EPCs was evaluated using a wound healing assay when rh-sCD146 (50 ng/mL) and VEGF (20 ng/mL) were added together and compared with the effect of each growth factor added separately. Results are the mean ± SEM values of 4 different experiments. (C) EPC capacity to elaborate pseudocapillaries in Matrigel plugs was evaluated in different conditions. Number of capillary-like structures was evaluated when rh-sCD146 (50 ng/mL) and VEGF (20 ng/mL) were added together and compared with the effect of each growth factor added separately. In addition, the effect of an anti-VEGFR2 antibody (Ab) preincubated before growth factor(s) addition was tested in control condition (Ab), in the presence of rh-sCD146 (Ab + rh-sCD146), in the presence of VEGF (Ab + VEGF), and in the presence of the 2 growth factors (Ab + rh-sCD146 + VEGF). In a last condition (washed Ab + rh-sCD146 + VEGF), the antibody was preincubated and then washed before addition of the 2 growth factors. Number of tubes was counted after 5 hours of incubation. Results are the mean ± SEM values of 6 different experiments. *P < .05, **P < .01, ***P < .001, experimental versus control.