Freshly isolated HUAECs and HUVECs have a different molecular and functional profile. An overview of the differential gene expression profile and corresponding functional signature of HUAECs and HUVECs. (A) Pie diagrams showing the number of annotated arterial (red) and venous (blue) genes emerging as differentially expressed between freshly isolated HUAECs and HUVECs from the differential gene statistical analysis (upper left) or classification analysis (upper right). The lower diagram shows the total amount of annotated genes and corresponding percentages (black lettering; arterial-enriched genes in red, venous-enriched genes in blue lettering) uniquely identified by the differential gene analysis (pink), from the classification analysis (yellow) or emerging from both analyses (orange; which included 4 genes, ie, HEY2, NOTCH4, SOX17, and KDR, previously associated with arterial specification). Other displayed names correspond to the most differentially expressed genes in each part of the diagram. (B-C) Bar diagrams showing functional terms (B) and pathways (C) significantly enriched in the 76 differential gene set. Numbers of associated genes per function/pathway are mentioned on top of the bars. Yellow bars represent subcategories of the main functional term “cardiovascular diseases.” (D) Bar diagram showing microarray probe set intensities (± standard error of the mean [SEM]; n = 4) for the 8 arterial (A) and 1 venous (V) TFs identified among the arteriovenous fresh profile, revealing their differential expression in freshly isolated HUAECs (red) and HUVECs (blue). *P < .05 vs arterial probe set intensity. (E-H) Immunofluorescence stainings on paraffin cross sections of human umbilical cord (umbilical vein is shown in E,G, umbilical artery in F,H) for αSMA (in green) and MSX1 (E-F; in red) or NR3C2 (G-H; in red). The curved bright red line in panel E represents an aspecific signal from the elastica interna. 4,6 Diamidino-2-phenylindole (blue) was used as nuclear counterstain. White arrowheads indicate positive staining in the endothelial lining. Scale bars: 20 μm. CV, cardiovascular; NO, nitric oxide; nNOS, neuronal nitric oxide synthase.