Quantitative real time PCR analysis (A) and representative confocal pictures (B) after analysis of endothelin-1 (EDN1) mRNA or protein expression in mPECs isolated from End.TGFβRII-WT and End.TGFβRII-KO mice and cultured in MV2 medium. Exact p-values, as determined by Mann-Whitney test are shown (n=6 biological replicates). Data are normalized to 18S and are expressed as -fold change vs. End.TGFβRII-WT mice (set at 1). Scale bars represents 10 μm. Plasma levels of ET-1 in samples from End.TGFβRII-WT and End.TGFβRII-KO mice uninjured (no IVC ligation; n=10 per group) and 21 days after IVC ligation (n=6 per group). Exact p-values, as determined by One-Way ANOVA followed by Bonferroni’s multiple comparisons test (4 comparisons), are shown. Non-significant p-values are not shown. Representative images of endothelin-1 protein expression in thrombosed vein wall segments 21 days after IVC ligation of End.TGFβRII-WT and End.TGFβRII-KO mice (D). Scale bars represent 10 μm. Quantitative analysis of thrombus area at day 21 after IVC ligation in End.TGFβRII-WT and End.TGFβRII-KO controls and mice treated with bosentan (n=5 per group; 5 mg/kg BW; E). Representative ultrasound images are shown in (F). Quantitative flow cytometry analysis of CD31- and CD31/FSP1 (n=4 per group; G) or CDH5- and CDH5/SMA (n=4 per group; H) double-positive cells residing within 21 day-old thrombi of End.TGFβRII-KO control- and bosentan-treated mice. Results in mice treated with bosentan are labeled in green. Exact p-values, as determined by Two-Way ANOVA followed by Bonferroni’s multiple comparisons test (6 comparisons; E) and multiple t test (G and H), are shown. Non-significant p-values are not shown.