Context: Vitamin D receptors are present in many tissues. Hypovitaminosis D is considered to be a risk factor for atherosclerosis. Objective: This study explores the effects of vitamin D replacement on insulin sensitivity, endothelial function, inflammation, oxidative stress, and leptin in vitamin D-deficient subjects. Design, Setting, and Patients: Twenty-three asymptomatic vitamin D-deficient subjects with 25-hydroxyvitamin D [25(OH)D] levels below 25 nmol/liter were compared with a control group that had a mean 25(OH)D level of 75 nmol/liter. The vitamin D-deficient group received 300,000 IU im monthly for 3 months. The following parameters were evaluated before and after treatment: vitamin D metabolites, leptin, endothelial function by brachial artery flow mediated dilatation (FMD), insulin sensitivity index based on oral glucose tolerance test, and lipid peroxidation as measures of thiobarbituric acid reactive substances (TBARS). Results: FMD measurements were significantly lower in 25(OH)D-deficient subjects than controls (P = 0.001) and improved after replacement therapy (P = 0.002). Posttreatment values of TBARS were significantly lower than pretreatment levels (P < 0.001). A positive correlation between FMD and 25(OH)D (r = 0.45; P = 0.001) and a negative correlation between FMD and TBARS (r = −0.28; P < 0.05) were observed. There was a significant increase in leptin levels after therapy, and the leptin levels were positively correlated with 25(OH)D levels (r = 0.45; P < 0.05). Conclusions: This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D-associated endothelial dysfunction may predispose to higher rates of cardiovascular disease in the winter. Endothelial dysfunction by flow mediated dilatation (FMD) in asymptomatic vitamin D deficient subjects improves significantly after vitamin D replacement.

Background. Accelerated atherosclerosis is the major cause of mortality in patients on chronic haemodialysis (HD). Increased oxidative stress might be the major factor leading to high cardiovascular mortality rate in HD patients. The aim of our study was to clarify effects of uraemia and dialysis on oxidative stress parameters and explore the relation between oxidative stress markers and carotid artery intima-media thickness (CIMT) as an indicator of atherosclerosis. Methods. Twenty chronic HD patients, 20 predialytic uraemic patients and 20 healthy subjects were included in the study. Serum thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCO) and nitrite/nitrate levels were determined as oxidative stress markers. Serum vitamin E, plasma sulfhydryl (P-SH), erythrocyte glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities were measured as antioxidants. CIMT was assessed by carotid artery ultrasonography. Results. Both chronic HD and predialytic uraemic patients had enhanced oxidative stress indicated by higher levels of nitrite/nitrate, TBARS and PCO, and lower levels of P-SH, SOD, CAT and GPx compared to controls. HD patients had significantly higher CIMT and nitrite/nitrate while significantly lower P-SH,vitamin E, SOD, CAT and GPx compared to predialytic uraemic patients. There was a significant positive correlation between CIMT and TBARS ( r = 0.38, P = 0.003) and nitrite/nitrate levels ( r = 0.41, P = 0.001), while there was a significant negative correlation between CIMT and SOD ( r = −0.35, P = 0.01), CAT ( r = −0.65, P < 0.001) and P-SH levels ( r = −0.50, P < 0.001). A linear regression analysis showed that TBARS were still significantly and positively correlated with CIMT ( P = 0.001), while CAT and P-SH were significantly and negatively correlated with CIMT ( P = 0.002 and P = 0.048, respectively). Conclusions. HD exacerbates oxidative stress and disturbances in antioxidant enzymes in uraemic patients. We propose that serum TBARS and nitrite/nitrate can be used as positive determinants, while erythrocyte SOD, CAT and P-SH may be used as negative determinants of atherosclerosis assessed by CIMT in uraemic and HD patients.

Background Right ventricular dysfunction and N-terminal proB-type natriuretic peptide (NT-proBNP) are established determinants of prognosis in acute pulmonary embolism (PE). The aim of the study was to investigate the prognostic value of C-reactive protein (CRP) in PE. Methods Fifty-six patients (mean age, 64.4 ± 14.8years; 22 male subjects) with acute PE were consecutively enrolled and followed for 36 months after discharge. Serum CRP, NT-proBNP, and troponin T levels were determined. Right ventricular function was evaluated by transthoracic echocardiography. Results Right ventricular dysfunction was present in 31 patients and was more frequent in patients with higher CRP and NT-proBNP levels (P = 0.020 and P = 0.045, respectively). During the 36-month follow-up, there were 15 terminal events (death due to recurrent PE). The mortality rate was 41.2% in patients with NT-proBNP levels greater than 1000 pg/mL, whereas it was 5.9% in patients with less than 500 pg/mL (P = 0.011). Mortality rates also were higher in patients with elevated CRP and troponin T levels, but the differences did not reach clinical significance. The survival rate of acute PE patients with lower NT-proBNP and CRP levels was better than that of patients with higher NT-proBNP and CRP levels. Receiver operating characteristic curve analysis demonstrated cutoff values for NT-proBNP as 1800 pg/mL (sensitivity, 93.3%; specificity, 68.2%; positive predictive values, 66.7%; and negative predictive values, 93.8%) and for CRP as 48mg/L (sensitivity, 72.7%; specificity, 61.9%; positive predictive values, 50.0%; and negative predictive values, 81.3%) to predict mortality in PE patients. Conclusions C-reactive protein is associated with right ventricular dysfunction, which is a predictor of prognosis in PE and may become a promising biomarker for risk stratification of PE, although CRP is not found superior to NT-proBNP.