Abstract 17492: Vitamin D Improves Endothelial Function In Experimental Hypertension
Introduction Vitamin D deficiency is becoming a world occurring phenomenon, with more than 1 billion elderly people affected in both sexes and all ethnic groups. Several comprehensive studies showed a direct link between low vitamin D plasma levels and periphery artery disease, hypertension, relative risk of myocardial infarction, increased mortality due to both chronic heart failure and sudden cardiac death, and all-cause and cardiovascular mortality. However, despite large-scale randomized clinical trials with vitamin D supplements, the molecular mechanisms of vitamin D activity on the cardiovascular endpoints are still needed to be elucidated.
Hypothesis We hypothesized that vitamin D increases nitric oxide bioavailability, affects endothelial nitric oxide expression (eNOS) and normalizes endothelial function in liquorice-induced hypertension.
Methods Endothelial function was analyzed in isolated aortic rings from 12-14 weeks old Wistar-Kyoto rats (WKY) treated with liquorice (3g/L) in drinking water (L) and compared to those which were co-administered with 1,25-dihydroxyvitamin D (L+D) (80 and 40 ng/day), or placebo (P) for three weeks.
Results Acetylcholine-induced endothelium dependent vasorelaxation in aortic rings from liquorice-treated WKY was impaired compared to either placebo-treated WKY or WKY which were co-administered with vitamin D (P<0.0001 and P<0.001, L vs P, L vs L+D, resp.). Notwithstanding increased calcium (P<0.0001, L vs L+D and P vs L+D) and phosphate (P=0.0219 L vs L+D) serum levels in a high dose vitamin D-treated WKY, acetylcholine-induced vasorelaxation was greatly improved (P<0.001 vs L), and there was reduction in generation of reactive oxygen species (P= 0.0051, L vs L+D, L vs P).
Conclusion Our study demonstrates that vitamin D treatment can improve endothelial function in experimental hypertension. Underlying mechanisms may include increased eNOS expression and reduced oxidative stress in endothelium.
- © 2012 by American Heart Association, Inc.