24-25-dihydroxyvitamin-d-3 and Vascular-Calcification

Vitamin D insufficiency is highly associated with cardiovascular morbidity and mortality. We have demonstrated enhanced vascular calcification in LDL receptor knockout (LDLR(-/-)) mice fed a diet low in vitamin D. This study aimed to investigate the impact of a diet low in vitamin D on vascular calcification in wild-type (WT) mice lacking atherosclerotic plaques and the effects of a persistent and discontinuous vitamin D insufficiency on atherosclerotic plaque composition in LDLR(-/-) mice. The study was performed with 4-wk-old male WT and LDLR(-/-) mice that were fed a normal calcium/phosphate Western diet (210 g/kg fat, 1.5 g/kg cholesterol) containing either adequate (+D; 1000 IU/kg) or low (-D; 50 IU/kg) amounts of vitamin D-3 for 16 wk. Four groups of LDLR(-/-) mice received 1 of the 2 diets for additional 16 wk (total 32 wk) and were compared with mice fed the diets for only 16 wk. WT and LDLR(-/-) mice that were fed the -D diet for 16 wk tended to develop more calcified spots in the aortic valve than mice fed the +D diet (+50% and +56%, respectively; P < 0.10). In LDLR(-/-) mice, the extent of calcification increased from week 16 to week 32 and was higher in the -D than in the +D group (P < 0.05). The calcification, owing to the -D diet, was accompanied by highly expressed osteoblast differentiation factors, indicating a transdifferentiation of vascular cells to osteoblast-like cells. Feeding the +D diet subsequent to the -D diet reduced the vascular calcification (P < 0.05). LDLR(-/-) mice fed the -D diet for 32 wk had higher plaque lipid depositions (+48%, P < 0.05) and a higher expression of cluster of differentiation 68 (+31%, P < 0.05) and tumor necrosis factor α (+134%, P < 0.001) than the +D group. Collectively, the findings imply low vitamin D status as a causal factor for vascular calcification and atherosclerosis.

Topics: 24,25-Dihydroxyvitamin D 3; Animal Feed; Animals; Aorta; Calcitriol; Calcium; Cholecalciferol; Genotype; Male; Mice, Inbred C57BL; Osteoblasts; Phosphates; Plaque, Atherosclerotic; Receptors, LDL; Vascular Calcification; Vitamin D; Vitamin D Deficiency; Vitamins

People with type 1 diabetes are at high risk of premature atherosclerosis. Existing evidence suggests that impaired vitamin D metabolism may contribute to the development of atherosclerosis. We tested associations of circulating vitamin D metabolite concentrations with subclinical atherosclerosis among 1,193 participants with type 1 diabetes in the DCCT/EDIC study.. We measured plasma concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D, and 24,25-dihydroxyvitamin D by mass spectrometry at the end of the DCCT. In a staggered cross-sectional design, we tested associations with coronary artery calcium (CAC), measured by computed tomography a median of 10 years later, and with common and internal carotid intima-media thickness (IMT), measured by B-mode ultrasonography on two occasions a median of 4 years later and a median of 10 years later. We hypothesized that lower concentrations of each vitamin D metabolite would be associated with increased risk of CAC and greater carotid IMT. RESULTS At the time metabolites were measured, mean age was 32.4 years and mean duration of diabetes was 7.5 years. The prevalence and severity of CAC tended to be lower-not higher-with lower concentrations of each vitamin D metabolite. For instance, in a fully adjusted multinomial logistic model, a 25 nmol/L lower 25-hydroxyvitamin D was associated with a 0.8-fold decrease in the odds of having higher CAC (95% CI 0.68-0.96, P = 0.01). No vitamin D metabolite was associated with either common or internal mean IMT.. We did not find evidence linking impaired vitamin D metabolism with increased subclinical atherosclerosis in type 1 diabetes.

Topics: 24,25-Dihydroxyvitamin D 3; Adult; Atherosclerosis; Calcium; Carotid Artery Diseases; Carotid Intima-Media Thickness; Coronary Artery Disease; Coronary Vessels; Diabetes Mellitus, Type 1; Female; Humans; Male; Vascular Calcification; Vitamin D