25-Hydroxyvitamin D insufficiency is associated with impaired renal endothelial function and both are improved with rosuvastatin treatment

Vitamin D deficiency is nowadays considered as a potential cardiovascular and renal risk factor. We tested the hypotheses that vitamin D deficiency impairs the endothelial function of renal vasculature and whether vitamin D levels and endothelial function can be improved by the treatment with statins. In a double-blind, randomized study of 31 hypercholesterolemic patients with vitamin D insufficiency (< 30 ng/ml) were randomly assigned to rosuvastatin (10 mg/d) and placebo for 6 weeks. Basal nitric oxide (NO) activity of the renal vasculature was assessed both before and after the blockade of NO synthases with systemic infusion of N(G)-monomethyl-l-arginine (l-NMMA). In parallel, 25(OH)D was measured. Multiple regression analysis revealed that at baseline 25(OH)D is an independent determinant of basal NO activity as assessed by the decrease in RPF, in response to l-NMMA (beta = -0.446, r = 0.015). Compared to placebo treatment, rosuvastatin increased 25(OH)D levels (21.6 +/- A 4.0 vs. 24.1 +/- A 8.1 ng/ml, p = 0.039). Basal NO activity was significantly more increased after 6-week therapy with rosuvastatin than with placebo (-94.8 +/- A 70 vs. -68.2 +/- A 32 ml/min, p = 0.044), indicating increased basal NOS activity after 6 weeks of rosuvastatin treatment. Basal NO activity in the placebo phase was correlated inversely with 25(OH)D (r = -0.385; p = 0.027). Thus, vitamin D insufficiency is associated with impaired endothelial function in the renal vasculature and both were beneficially influenced by the treatment with rosuvastatin.