Age-dependent loss of EPCR from the renal vascular endothelium in SS mice. (A) Plasma and (B) urine collected from older (10-month) AA mice (n = 5-6; M, 2; F, 3-4) and differentially aged (1-10 months) SS mice (n = 5-6; M, 2; F, 3-4) showing a gradual age-dependent increase in plasma and urinary sEPCR in SS mice. (C) Representative immunofluorescence images showing the loss of EPCR from the renal microvascular endothelium in older SS mice (6 months or 10 months) compared with younger mice (1 or 3 months). CD31 is an endothelial marker (scale bar = 50 μm). (D) The ratio of the staining intensity of EPCR and CD31 was calculated from the older AA mice (10 months; n = 5; M, 2; F, 3) and SS mice of the indicated age (n = 5; M, 2; F, 3 in each age group) using ImageJ software. The EPCR staining intensity gradually diminished with age in the SS mice. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001 (1-way ANOVA between differentially aged SS mice and unpaired Student t test between 10-month-old AA and SS mice).