Differentiation in Vitro of Two Types of Human Umbilical Cord Blood-derived Endothelial Progenitor Cells

【Objective】 To investigate the method for culturing two types of endothelial progenitor cells(EPCs) from human umbilical cord blood and study their differentiation traits.【Methods】 Mononuclear cells were isolated from fresh cord blood by 6% HES and density gradient centrifugation.Isolated cells were cultured in medium supplemented with VEGF and bFGF.The growth situation and biological features of the cells were observed at different time points and identified by morphology,immunofluorescence staining,RT-PCR and flow cytometry.【Results】 Attached cells were divided into two types of EPCs,i.e.early EPCs and late EPCs.Early EPCs changed from small sized round cells to spindle shape cells,and late EPCs formed a typical cobblestone-like cells.Fluorescence microscopy showed that EPCs were positive for both DiI-acLDL uptake and FITC-ulex-lectin binding.RT-PCR and FACS showed the difference of endothelial cell-specific,gene expression and changed AC133,CD34 and KDR among different times.MTT assay showed the different proliferation kinetics among different times.【Conclusion】 There are two different types of EPCs from human umbilical cord blood and those provide a basis for further research.