Endothelial and progenitor cell marker expression in VV endothelial cells (VVEC). Quantitative RT-PCR analysis was performed on total cellular mRNA isolated from VVEC-Co and VVEC-Hx populations. Expression level of CD31, CD34, CD133, CD105, and c-kit was calculated relative to bovine 18S RNA in VVEC-Co and VVEC-Hx. Data represent mean relative mRNA expression in VVEC-Co and VVEC-Hx; P = 0.0303 (CD31); P = 0.5303 (CD34); P = 0.8763 (CD133); P = 0.0303 (CD105); P = 0.0408 (c-kit); *P < 0.05 (Student's t-test, followed by a Mann-Whitney posttest).