Common Iliac Artery Vitamin D Receptor Expression Patterns During the Development of Atherosclerosis in Postmenopausal Nonhuman Primates

Objective: The results of recent studies suggest that vitamin D receptor (VDR) expression in the coronary arteries of female cynomolgus monkeys is negatively associated with atherosclerosis extent and severity. The objective of this study is to assess the changes in VDR expression in the common iliac arteries of postmenopausal monkeys during the development of atherosclerosis. Design: After 32 months of consuming an atherogenic diet, 37 premenopausal monkeys underwent ovariectomy. The same diet was then consumed for an additional 32 months until necropsy. Atherosclerosis extent and VDR expression were measured in the left iliac artery (LCI) at the time of ovariectomy, and in the right common iliac artery (RCI) at necropsy. Atherosclerosis severity (American Heart Association grading system) and VDR expression (VDR H-score) were quantified. Results: Despite increasing atherosclerosis over the course of the study, the total mean (SD) VDR H-score was significantly higher in the RCI in postmenopausal monkeys after consuming the athrogenic diet for a total of 64 months compared to the LCI of premenopausal monkeys who consumed the diet for 32 months (152.62[18.55] vs. 126.15[22.13], p\u3c.001). There was a significant positive correlation between the absolute (and percentage) change in total H-score and absolute change of AHA severity from preto post-menopause (Absolute: r=0.43, p=.008; Percentage: r=0.44, p=.007). Conclusion: Overall, contrary to our expectation, VDR expression was significantly increased in direct correlation with atherosclerosis increase in postmenopausal monkeys. A higher increase in VDR expression, from pre- to post-menopause, correlated with more severe atherosclerotic changes in the common iliac arteries