Isolation of cultured endothelial progenitor cells in vitro from PBMCs and CD133+ enriched cells

Two isolation methods for sorting of endothelial progenitor cells (EPCs): from peripheral blood mononuclear cells (PBMCs) and CD133+ enriched cells were compared, by defining the cell morphology, phenotype, reproductive activities and function in vitro, to provide a reference for clinical application of EPCs. PBMCs from healthy subjects were used either directly for cell culture or for CD133+ sorting. The two groups of cells were cultured in complete medium 199 (M199) for 7 to 14 days and the phenotypes of EPCs were analyzed by FACS. The proliferation of differentiated EPCs was studied by MTT assay, and the VEGF concentration was measured using an ELISA kit. ECM gel experiment and migration assay were performed in vivo. The results showed that PBMCs produced more colony-forming units (CFU) than CD133+ enriched cells from the same volume of blood (P<0.01). From day 7 to 14, the two groups showed decreased expression of hematopoietic stem cell markers and increased level of endothelial markers, but CD144+ cells in CD133+ group were less than in PBMCs group (P<0.01). PBMCs group secreted more VEGF than CD133+ group on the day 7 (P<0.01). As compared with CD133+ group, PBMCs group had more potent potential of proliferation and vascularization in vitro. It was concluded that CD133+ sorted cells showed a lower capacity of differentiation, secretion, proliferation and vascularization in vitro, suggesting that CD133-negative cells may be a preferential way to get EPCs for clinical therapy.