Cholecalciferol treatment downregulates renin-angiotensin systemand improves endothelial function in essential hypertensive patients with hypovitaminosid D

Background: Vitamin D deficiency is related to an increased prevalence of cardiovascular disease. Renin- angiotensin-aldosterone system suppression and vascular dysfunction are considered among the main mechanisms implicated in this association. However, interventional studies demonstrating that vitamin D replacement reduces circulating renin-angiotensin-aldosterone components and improves vascular function in humans are still lacking. Methods: Thirty-three consecutive patients with essential hypertension and hypovitaminosis D underwent therapy with cholecalciferol 50 000 IU/week orally for 8 weeks. Thirty-three hypertensive patients with normal vitamin D levels and 20 normotensive individuals were also enrolled as control groups. At baseline and at the end of the study, we evaluated plasma renin activity, circulating renin, angiotensin II, aldosterone and plasma vitamin D levels. Endothelial function [flow-mediated dilation (FMD)], carotid-femoral pulse wave velocity and augmentation index, peripheral and central blood pressure were also acquired. Results: After 8-week cholecalciferol administration, all treated patients normalized plasma 25(OH)D values. Furthermore, a reduction in plasma levels of plasma renin activity (1.17±0.3 vs 1.51±0.4 ng/ml per h, P=0.02), renin (13.4±1.7 vs 19.2±2.9 pg/ml, P<0.001), angiotensin II (11.6±1.6 vs 15.8±2.7 pg/ml, P=0.02) was observed at the end of the study. FMD was significantly increased after cholecalciferol treatment (4.4±2.6 vs 3.3±2.1%, P