EC marker expression and characterization. (A) Cytometric analysis of ECs and hematopoietic markers in cultured HemEPCs, HemECs, cbEPCs, and HDMECs. Solid gray histograms represent cells stained with fluorescence-conjugated antibodies. Black lines show cells stained with fluorescence-conjugated isotype control antibodies. (B) Indirect immunofluorescent staining of cells, grown in monolayers, with CD31, VE-cadherin, and VWF antibodies showing positive staining for EC markers (all cells were passage 8). Images were taken with a Nikon Eclipse TE300 (Nikon, Melville, NY) using Spot Advanced 3.5.9 software (Diagnostic Instruments, Sterling Heights, MI) and a 20×/0.45 objective lens.