Objective The purpose of this study was to determine the role

Objective The purpose of this study was to determine the role of the endothelial glucocorticoid receptor in the pathogenesis of atherosclerosis. more severe atherosclerotic lesions in the aorta brachiocephalic artery and aortic sinus as well as a heightened inflammatory milieu as evidence by increased macrophage recruitment in the lesions. Conclusions These data suggest the endothelial glucocorticoid receptor is important for tonic inhibition of inflammation and limitation of atherosclerosis progression in this model. knockout background. Here we show that loss of the endothelial GR worsens the atherosclerotic phenotype suggesting that endogenous corticosterone acting via endothelial GR tonically suppresses vascular inflammation and plays a role in limiting the progression of atherosclerosis. MATERIALS AND METHODS Material and Methods are available in the online-only Data Supplement. RESULTS Littermate ((DKO) mice were fed a high fat diet (HFD) for 12 weeks as described.9 Previously we have documented the endothelial specificity of the Complanatoside A deleted GR in several studies.1 3 Both groups of mice had similar weights (Fig 1A) triglycerides (Fig 1B) cholesterol levels (Fig 1C) and corticosterone levels (Fig 1D) at baseline and after feeding mice with HFD. Similar corticosterone levels were indicative that there was no derangement in the hypothalamic-pituitary-adrenal axis in DKO animals nor evidence of heightened stress in these animals. These results are in agreement with previously published work.1 Figure 1 Loss of the endothelial glucocorticoid receptor accelerates atherosclerosis in Apo E ?/? mice (A) Weight is significantly increased in both groups Complanatoside A following 12 weeks of HFD feeding. (B) No significant difference in triglycerides before … At the completion of the feeding period mice were sacrificed perfused and the extent of atherosclerosis in multiple vessels was examined. Aortas were stained with Oil Red O and the percentage of total aortic neutral lipids deposition quantified. As shown in Figure 1E and quantified in 1F DKO mice showed significantly greater lesion areas than did mice. There were no differences noted in the anatomic distribution of the lesions when suprarenal and infrarenal aortas were analyzed separately (Figure I-online only Data Supplement). Similar results were obtained in cross sections of brachiocephalic arteries (Figs 1G and H). To determine if the increased lesion size in the DKO mice was associated with heightened inflammation tissue macrophages (via CD68 labeling) were assessed immunohistochemically. As shown in Figure 2A and quantified in Figure 2B DKO animals showed greater macrophage accumulation in the atherosclerotic lesions of brachiocephalic arteries indicating a heightened Complanatoside A inflammatory state. As additional evidence that inflammation was increased in the DKO animals staining for VCAM was also performed in these vessels. DKO mice Rabbit polyclonal to PDCL2. also showed increased VCAM-positive staining in the atherosclerotic lesions (Figure II-online only Data Supplement). Figure 2 More inflammation and larger cardiac lesions in Apo E ?/? mice lacking the endothelial glucocorticoid receptor. (A) Representative immunofluorescent sections of brachiocephalic lesions stained with DAPI and CD68. Dotted line indicates … We also examined aortic root lesions in hearts from and Complanatoside A DKO mice. Hearts were prepared and sectioned as described above to allow visualization of the aortic sinus lesions and representative sections are shown in Figure 2C. Quantification of Oil Red O staining/lesion area (Figure 2D) and total lesion area (Figure 2E) showed more extensive lesions in DKO mice compared to mice. Macrophage infiltration was also assessed in aortic root lesions via CD68 staining. As shown in Figure 2C and quantified in 2F DKO mice had increased absolute macrophage area. In addition lesions in the coronary ostiae were identified in Complanatoside A 3/6 DKO mice but in none of the mice (Figure III- online only Data Supplement). In Complanatoside A a separate series of experiments mice were fed the Paigen diet to examine the effect of diet-induced TLR4-dependent inflammation on lesion progression.10 11 Though this diet has been studied in this context previously it is important to note that it may have other effects which were not assessed in our study. Importantly only 6 out of 16 DKO mice survived this diet whereas 12 out of 13 mice.