Immunofluorescence analysis and ultrastructural studies. (A) Immunofluorescence analysis of EPDCs, HUVECs, and HBMECs. Cells were stained with antibody against VWF, CD144, CD31, or collagen IV. EPDCs as well as HUVECs and HBMECs take up Dil-Ac-LDL and were positively stained with VWF, CD144, CD31, or collagen IV antibodies. Scale bar equals 5 μm. (B) Ultrastructural studies of EPDCs and HUVECs. EPDCs and HUVECs were fixed and prepared for transmission electron microscopy. Scale bar equals 1 μm. Arrowheads indicate Weibel-Palade bodies.