Effects of hemin on quantity and apoptosis of human umbilical cord blood-derived late endothelial progenitor cells

Abstract

Objective To investigate the effects of hemin on the quantity and apoptosis of human umbilical cord blood-derived late endothelial progenitor cells (EPCs) in vitro. Methods Mononuclear cells were isolated from human cord blood by density gradient centrifugation and were induced to differentiate to late EPCs in vitro. The second to third generation of attached late EPCs in good state were randomly plated for 24 h under different concentrations(0, 5, 10, 15 and 20 μmol/L)of hemin. Cell viability and proliferation were measured with typan blue staining and cell counting kit-8, respectively. Cell adhesion was analyzed by adhesive assay, and cell apoptosis was detected by flow cytometry. Results Compared to control group, hemin promoted viability of late EPCsat lower concentrations(5and 10μmol/L). Meanwhile, proliferation and adhesion were also improved and apoptosis was inhibited when the concentrations of hemin were 5, 10, or 15 μmol/L. All these effects were most prominent when hemin concentration was 10 μmol/L, while the effects above were reversed when hemin concentration was moderated to 20 μmol/L. In addition, hemin showed a time-dependent manner in promoting cell proliferation and adhesion, and inhibiting apoptosis. That effects were most obvious at 24 h. Conclusions Lower concentration of hemin augments the quantity and adhesion of late EPCs, inhibits cell apoptosis, while higher concentration present the reversed effects. Key words: Hemin/PD; Fetal blood/CY; Endothelial cells/DE/PA; Apoptosis