Smooth muscle cells were identified by immunofluorescence and RT-PCR. EPC morphology changed after induction with PDGF-BB at day 7, whereby the cells became longer in shape and formed structures typical of muscle cells. The induced cells were negative for the stem cell marker CD133 and positive for the smooth muscle cells marker α-MSA, as detected by immunofluorescence and RT-PCR. A and D. Phase contrast; B. α-MSA+; E. CD133- C. and F. Merge; G. smooth muscle cells marker α-MSA detection via RT-PCR, 1: Marker. 2: GAPDH. 3: α-MSA.