Blood outgrowth endothelial cells from cord blood and peripheral blood: angiogenesis-related characteristics in vitro

Summary.  Background:  Blood outgrowth endothelial cells (BOEC) are good candidates for vascular (re-) generating cell therapy. Although cord blood (CB) BOEC have been reported as more proliferative than peripheral blood (PB) BOEC, not much is known about their functional properties. Objectives:  We have studied the following determinants in BOEC expanded from CB and PB: endothelial phenotype, in vitro adhesion, migration, proliferation, and angiogenic tube forming capacity. Methods/Results:  Endothelial phenotype of BOEC was evaluated by fluorescence activated cell sorting (FACS) analysis and confirmed the presence of endothelial markers including CD31, CD105, CD144, CD146, KDR/VEGFR-2, Tie-2, and TNF-α-induced VCAM-1 and ICAM-1. Evaluation of cell proliferation revealed a higher basal proliferation of CB-BOEC, which increased after exposure to bFGF but not VEGF. The lower basal proliferation of PB-BOEC increased with VEGF or bFGF addition. Array analysis of angiogenic genes showed many comparable expressions in both BOEC, and a slightly more pronounced pro-angiogenic profile in CB-BOEC than PB-BOEC. Both BOEC were able to form tubular structures in a three-dimensional fibrin matrix. Tube formation in CB-BOEC was markedly induced by TNF-α only and inhibited by anti-urokinase antibodies. It was comparable to that induced by combined addition of TNF-α and VEGF or bFGF, while maximal tube formation in PB-BOEC required simultaneous exposure to TNF-α/VEGF or TNF-α/bFGF. Conclusions:  The endothelial phenotype and characteristics for homing, adhesion, migration, inflammation, and angiogenic tube formation are almost equal for BOEC from CB and PB. A slightly more angiogenic phenotype favors CB-BOEC. However, addition of VEGF to PB-BOEC induces equal proliferation and tube formation.