Effect of VEGI treatment on EPC viability and apoptosis. (A) Number of suspended cells cultured in the absence or presence of VEGI and measured by relative fluorescence units (RFUs) of calcein-AM staining at various time intervals. (B) Number of adhered cells analyzed as described in panel A. (C) Fluorescent images of suspended and adherent cells undergoing apoptosis at various time points as indicated. Red represents cells labeled by TUNEL reaction; green, E-selectin; blue, cell nuclei (10× objective lens). (D) Fluorescence intensity of E-selectin–positive EPCs analyzed at various time intervals as indicated. (E) Apoptosis rates of suspended cells and adhered cells analyzed at various time intervals as indicated. (F) Apoptosis rates of E-selectin–positive or–negative cells in EPC cultures on day 7. *P < .05.