Classification of Vitamin D Status Based on Vitamin D Metabolism: A Randomized Controlled Trial in Hypertensive Patients.

Circulating 25-hydroxyvitamin D (25(OH)D) is the generally accepted indicator of vitamin D status. Since hydroxylation of 25(OH)D to 24-25-dihydroxyvitamin D (24,25(OH)2D) is the first step of its catabolism, it has been suggested that a low 24,25(OH)D level and a low vitamin D metabolite ratio (VMR), i.e., 24,25(OH)2D divided by 25(OH)D, may indicate high vitamin D requirements and provide additional diagnostic information beyond serum 25(OH)D. We, therefore, evaluated whether the classification of "functional vitamin D deficiency", i.e., 25(OH)D below 50 nmol/L, 24,25(OH)2D below 3 nmol/L and a VMR of less than 4%, identifies individuals who benefit from vitamin D supplementation. In participants of the Styrian Vitamin D Hypertension trial, a randomized controlled trial (RCT) in 200 hypertensive patients with serum 25(OH)D below 75 nmol/L, who received either 2.800 international units of vitamin D per day or placebo over 8 weeks, 51 participants had functional vitamin D deficiency. In these individuals, there was no treatment effect of vitamin D supplementation on various parameters of bone metabolism and cardiovascular risk except for a significant effect on parathyroid hormone (PTH) and expected changes in vitamin D metabolites. In conclusion, a low vitamin D metabolite profile did not identify individuals who significantly benefit from vitamin D supplementation with regard to bone markers and cardiovascular risk factors. The clinical significance of functional vitamin D deficiency requires further evaluation in large vitamin D RCTs.

Hypercalcemia in Pregnancy Due to CYP24A1 Mutations: Case Report and Review of the Literature.

Pathogenic mutations of CYP24A1 lead to an impaired catabolism of vitamin D metabolites and should be considered in the differential diagnosis of hypercalcemia with low parathyroid hormone concentrations. Diagnosis is based on a reduced 24,25-dihydroxyvitamin D to 25-hydroxyvitamin D ratio and confirmed by genetic analyses. Pregnancy is associated with an upregulation of the active vitamin D hormone calcitriol and may thus particularly trigger hypercalcemia in affected patients. We present a case report and a narrative review of pregnant women with CYP24A1 mutations (13 women with 29 pregnancies) outlining the laboratory and clinical characteristics during pregnancy and postpartum and the applied treatment approaches. In general, pregnancy triggered hypercalcemia in the affected women and obstetric complications were frequently reported. Conclusions on drugs to treat hypercalcemia during pregnancy are extremely limited and do not show clear evidence of efficacy. Strictly avoiding vitamin D supplementation seems to be effective in preventing or reducing the degree of hypercalcemia. Our case of a 24-year-old woman who presented with hypercalcemia in the 24th gestational week delivered a healthy baby and hypercalcemia resolved while breastfeeding. Pathogenic mutations of CYP24A1 mutations are rare but should be considered in the context of vitamin D supplementation during pregnancy.

Development of a liquid chromatography mass spectrometry method for the determination of vitamin K1, menaquinone-4, menaquinone-7 and vitamin K1-2,3 epoxide in serum of individuals without vitamin K supplements.

OBJECTIVES: Vitamin K and metabolites have a beneficial role in blood coagulation, bone metabolism and growth. However, the determination of vitamin K concentrations in the blood in patients consuming a diet with naturally occurring vitamin K is currently challenging. We aim to develop a cost-effective and rapid method to measure vitamin K metabolites with potential application for clinics and research. METHODS: We developed a simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of vitamin K1, menaquinone-4 (MK-4), menaquinone-7 (MK-7) and vitamin K1-2,3 epoxide in human serum and validated the method in a study cohort of 162 patients tested for carbohydrate malabsorption and in 20 patients with oral phenprocoumon intake. RESULTS: The overall precision (CVs) ranged between 4.8 and 17.7% in the specified working range (0.06-9.0 nmol/L for all analytes except for MK-7 with 0.04-6.16 nmol/L). In the malabsorption cohort samples, measured values were obtained for all different vitamin K metabolites except for vitamin K1-2,3 epoxide. This metabolite could be detected only in patients with phenprocoumon intake. The good performance of the method is especially achieved by the interaction of three factors: the use of lipase in the sample preparation, the use of an atypical fluorinated reversed phase column, and a logarithmic methanol gradient. CONCLUSIONS: The described method is able to determine the concentration of four vitamin K metabolites in a time-efficient, simple and cost-effective manner. It can be suitable for both routine clinics and research.

Randomized trial of vitamin D versus placebo supplementation on markers of systemic inflammation in hypertensive patients.

BACKGROUND AND AIMS: Animal and cell models indicated that vitamin D modulates inflammatory activity, which is considered relevant in the pathogenesis of arterial hypertension and cardiovascular diseases. We therefore aimed to investigate the effect of vitamin D supplementation on systemic markers of inflammation in a cohort of hypertensive patients. METHODS AND RESULTS: The Styrian Vitamin D Hypertension Trial is a single-centre, double-blind, placebo-controlled study conducted from 2011 to 2014 in Austria. We enrolled 200 study participants with arterial hypertension and 25-hydroxy-vitamin-D (25(OH)D) concentration below 30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D3 per day or placebo for 8 weeks. The present investigation is a post-hoc analysis using analysis of co-variance (ANCOVA). Outcome measures were biomarkers of inflammation including CRP, leukocytes including subtypes and leukocyte-to-lymphocyte ratio, leucine and kynurenic acid. A total of 187 participants (mean age 60.1 ± 11.3years; 47% women; mean baseline 25(OH)D 21.1 ± 5.6 ng/mL) completed the trial. ANCOVA revealed a mean treatment effect for none of the respective outcomes and no significant results were detected in various subgroup analyses. CONCLUSION: Vitamin D3 supplementation in hypertensive patients with insufficient 25(OH)D concentrations has no significant effect on lowering markers of systemic inflammation. Further studies investigating the effect of vitamin D on other inflammatory pathways and in populations with severe vitamin D deficiency and a significant inflammatory burden are required. REGISTRATION: ClinicalTrials.gov Identifier: NCT02136771; EudraCT No. 2009-018,125-70. Start Date: 2011-04-06.

Association of vitamin D metabolites with cognitive function and brain atrophy in elderly individuals - the Austrian stroke prevention study.

BACKGROUND: Vitamin D is a well-established regulator of calcium and phosphate metabolism that has neurotrophic and neuroprotective properties. Deficiency of vitamin D has been proposed to promote cognitive dysfunction and brain atrophy. However, existing studies provide inconsistent results. Here we aimed to investigate the association between vitamin D metabolites, cognitive function and brain atrophy in a cohort of well-characterized community-dwelling elderly individuals with normal neurological status and without history of stroke and dementia. METHODS: 25(OH)D3, 25(OH)D2 and 24,25(OH)2D3 were measured by liquid-chromatography tandem mass-spectrometry in serum samples from 390 community-dwelling elderly individuals. All participants underwent thorough neuropsychiatric tests capturing memory, executive function and visuopractical skills. In 139 of these individuals, MRI of the brain was performed in order to capture neurodegenerative and vascular changes. RESULTS: Total 25(OH)D (ß=0.003, 0.037), 24,25(OH)2D3 (ß=0.0456, p=0.010) and vitamin D metabolite ratio (VMR) (ß=0.0467, p=0.012) were significantly related to memory function. Adjustment for multiple testing weakened these relationships, but trends (p≤0.10) remained. 24,25(OH)2D3 and VMR showed similar trends also for visuopractical skills and global cognitive function. No significant relationships existed between vitamin D metabolites and MRI derived indices of neurodegeneration and vascular changes. Sub-group analyses of individuals with low concentrations of 25(OH)D and 24,25(OH)2D3 showed significantly worse memory function compared to individuals with normal or high concentrations. CONCLUSIONS: Vitamin D deficient individuals appear to have a modest reduction of memory function without structural brain atrophy. Future studies should explore if vitamin D supplementation can improve cognitive function.

Effects of Vitamin D Supplementation on Plasma Aldosterone and Renin-A Randomized Placebo-Controlled Trial.

Increasing evidence describes a possible interplay between vitamin D insufficiency with increased aldosterone. The authors sought to evaluate the effect of vitamin D supplementation on plasma aldosterone concentration (PAC) in patients with hypertension and 25-hydroxyvitamin D[25(OH)D] insufficiency. The Styrian Vitamin D Hypertension Trial was a single-center, double-blind, placebo-controlled randomized clinical trial conducted from 2011 to 2014. Two hundred patients with arterial hypertension and 25(OH)D levels <30 ng/mL were enrolled. Study participants were randomized to receive either 2800 IU of vitamin D3 or placebo. The present investigation is a post hoc analysis using analysis of covariance adjusting for baseline differences. A total of 188 participants (mean±standard deviation age, 60.1±11.3 years; 47% women; 25(OH)D, 21.2±5.6 ng/mL) completed the trial. Mean differences between baseline and follow-up PAC in the control and intervention arm were +3.3 ng/dL and +0.9 ng/dL, respectively (P=.04). The findings indicate that vitamin D3 supplementation significantly decreases PAC in patients with arterial hypertension and 25(OH)D insufficiency.

Homoarginine in the renal and cardiovascular systems.

Homoarginine (hArg) is an endogenous, nonproteinogenic amino acid which differs from arginine by an additional methylene (CH2) group in the backbone. In this brief narrative review, we summarize the current literature on hArg in the renal and cardiovascular systems. Epidemiological studies have identified low hArg levels as an independent risk marker for cardiovascular, cerebrovascular, and renal diseases as well as for mortality. The relatively low correlation of hArg with established cardiovascular risk factors underlines its great potential as an emerging biomarker to improve risk prediction because plasma hArg concentrations might reflect previously unrecognized pathophysiological processes. hArg may be involved in the pathogenesis of various diseases due to its effects on nitric oxide (NO) and energy metabolism. In view of its structural similarities with arginine, it has been proposed that hArg impacts on arginine metabolism and subsequently also on NO synthesis. The key enzyme for hArg synthesis, arginine:glycine amidinotransferase (AGAT), is involved in the synthesis of energy metabolites including guanidinoacetate, the precursor of creatine. Therefore, the involvement of hArg in energy metabolism could partially explain the close association between hArg and cardiovascular diseases such as heart failure. Whether hArg supplementation or modification of key enzymes of hArg metabolism such as AGAT activity is effective for the treatment of chronic diseases remains to be elucidated.

Effects of vitamin D on blood pressure and cardiovascular risk factors: a randomized controlled trial.

UNLABELLED: Vitamin D deficiency is a risk factor for arterial hypertension, but randomized controlled trials showed mixed effects of vitamin D supplementation on blood pressure (BP). We aimed to evaluate whether vitamin D supplementation affects 24-hour systolic ambulatory BP monitoring values and cardiovascular risk factors. The Styrian Vitamin D Hypertension Trial is a single-center, double-blind, placebo-controlled study conducted from June 2011 to August 2014 at the endocrine outpatient clinic of the Medical University of Graz, Austria. We enrolled 200 study participants with arterial hypertension and 25-hydroxyvitamin D levels below 30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D3 per day as oily drops (n=100) or placebo (n=100) for 8 weeks. Primary outcome measure was 24-hour systolic BP. Secondary outcome measures were 24-hour diastolic BP, N-terminal-pro-B-type natriuretic peptide, QTc interval, renin, aldosterone, 24-hour urinary albumin excretion, homeostasis model assessment-insulin resistance, triglycerides, high-density lipoprotein cholesterol, and pulse wave velocity. A total of 188 participants (mean [SD] age, 60.1 [11.3] years; 47% women; 25-hydroxyvitamin D, 21.2 [5.6] ng/mL) completed the trial. The mean treatment effect (95% confidence interval) for 24-hour systolic BP was -0.4 (-2.8 to 1.9) mm Hg (P=0.712). Triglycerides increased significantly (mean change [95% confidence interval], 17 [1-33] mg/dL; P=0.013), but no further significant effects were observed for secondary outcomes. Vitamin D supplementation in hypertensive patients with low 25-hydroxyvitamin D has no significant effect on BP and several cardiovascular risk factors, but it was associated with a significant increase in triglycerides. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02136771.

Synergistic effects of NOD1 or NOD2 and TLR4 activation on mouse sickness behavior in relation to immune and brain activity markers.

Toll-like receptors (TLRs) and nuclear-binding domain (NOD)-like receptors (NLRs) are sensors of bacterial cell wall components to trigger an immune response. The TLR4 agonist lipopolysaccharide (LPS) is a strong immune activator leading to sickness and depressed mood. NOD agonists are less active but can prime immune cells to augment LPS-induced cytokine production. Since the impact of NOD and TLR co-activation in vivo has been little studied, the effects of the NOD1 agonist FK565 and the NOD2 agonist muramyl dipeptide (MDP), alone and in combination with LPS, on immune activation, brain function and sickness behavior were investigated in male C57BL/6N mice. Intraperitoneal injection of FK565 (0.001 or 0.003mg/kg) or MDP (1 or 3mg/kg) 4h before LPS (0.1 or 0.83mg/kg) significantly aggravated and prolonged the LPS-evoked sickness behavior as deduced from a decrease in locomotion, exploration, food intake and temperature. When given alone, FK565 and MDP had only minor effects. The exacerbation of sickness behavior induced by FK565 or MDP in combination with LPS was paralleled by enhanced plasma protein and cerebral mRNA levels of proinflammatory cytokines (IFN-γ, IL-1ß, IL-6, TNF-α) as well as enhanced plasma levels of kynurenine. Immunohistochemical visualization of c-Fos in the brain revealed that NOD2 synergism with TLR4 resulted in increased activation of cerebral nuclei relevant to sickness. These data show that NOD1 or NOD2 synergizes with TLR4 in exacerbating the immune, sickness and brain responses to peripheral immune stimulation. Our findings demonstrate that the known interactions of NLRs and TLRs at the immune cell level extend to interactions affecting brain function and behavior.

A biopsychosocial model of interferon-alpha-induced depression in patients with chronic hepatitis C infection.

BACKGROUND: The aim of this prospective study was to gain a more comprehensive picture of the biopsychosocial effects of interferon-α (IFN-α) treatment of patients with chronic hepatitis C (HCV). The predictors of depressive development and changes in health-related quality of life, life satisfaction and cognitive ability were measured with the inclusion of the social context. Furthermore, the effects of IFN-α treatment on indoleamine 2,3-dioxygenase, the level of tryptophan supply in the brain, the development of neurotoxic kynurenine metabolites and the thyroid glands were investigated. Therefore, for the first time the conditions for the development of depressive episodes in HCV patients treated with IFN-α were examined over the entire period of treatment as well as 3 months later, applying a holistic biopsychosocial model. METHOD: Psychiatric and biological assessments were carried out at 6 different times: before, during (at 1, 3, 6 and 9 months) and after the end of IFN-α treatment. RESULTS: During IFN-α treatment 22 (53.7%) of 41 patients fulfilled the criteria for a treatment-related depressive disorder at least once during treatment. Contributing factors are tryptophan depletion (tryptophan to competing amino acids quotient), increased neurotoxic challenge (kynurenine to kynurenic acid quotient), less social support, female gender, preexisting psychiatric vulnerability, means of transmission, low financial security, impaired sexual satisfaction, small circle of friends, impaired physical role, strong body pain, low general health and vitality, reduced social functioning, impaired mental health and impaired emotional role. CONCLUSIONS: The awareness of relevant risk factors of IFN-α treatment-induced depression is essential to develop preventative treatment strategies.

Vitamin D and cardiovascular disease: update and outlook.

Accumulating evidence suggests that vitamin D may play a role for cardiovascular health. Expression of the vitamin D receptor (VDR) and enzymes for vitamin D metabolism have been identified in the vasculature as well as in the heart. VDR knock-out mice suffer from cardiovascular disease (CVD) and even selective VDR deletion in cardiomyocytes causes myocardial hypertrophy. Many, but not all observational studies showed that vitamin D deficiency is associated with CVD and its risk factors. Low concentrations of 25-hydroxyvitamin D (25(OH)D) are an independent risk factor for cardiovascular events, in particular for strokes and sudden cardiac deaths. Only few randomized controlled trials (RCTs) are available on this topic. These RCTs are frequently limited by the additional supplementation of calcium which may increase the risk of CVD events. RCTs with pure vitamin D supplementation have partially but not consistently shown beneficial effects on cardiovascular risk factors such as arterial hypertension. A number of large RCTs on the impact of vitamin D supplementation on cardiovascular events and mortality have already started but limitations of the study designs such as inclusion of individuals with relatively high 25(OH)D concentrations have to be considered. At present, the evidence is not sufficient for general recommendations to supplement vitamin D in order to prevent and treat CVD. It should, however, be noted that justification for the prevention and treatment of vitamin D deficiency comes from evidence based benefits of vitamin D supplementation on musculoskeletal health.

Psychological and systemic stress reactions of patients during hyperthermia treatments.

PURPOSE: This study evaluated psychological stress reactions during hyperthermia (HT) treatments and compared them to systemic stress reactions. MATERIALS AND METHODS: 27 patients with malignant disease were treated with superficial or regional hyperthermia. Cortisol and the catecholamines adrenaline and noradrenaline in venous blood were used as markers of psychological stress. The anxiety proneness of the patients was evaluated with a trait-anxiety inventory. Blood pressure and heart rate were markers of systemic stress. Patients were first grouped by superficial or regional treatment and then into two subgroups: anxious and non-anxious patients. RESULTS: The time course of the cortisol concentration of the superficial group showed a slight but significant decrease and that of the regional group an increase. The cortisol concentration of the regional group was sometimes slightly but significantly higher than in the superficial group, and in the group of anxious patients higher than in the group of non-anxious patients. The changes in time courses and differences in groups were not as pronounced for the catecholamine concentrations. Heart rate and blood pressure showed a significant increase only in the regional group, and there was no significant difference between the regional and the superficial groups. None of the variables showed a significant difference between the initial and the subsequent treatments; all lay well within the normal physiological range. CONCLUSIONS: These standard hyperthermia treatments are not excessively stressful, either systemically or psychologically. The different behaviours of the variables confirm that it makes sense to consider systemic stress as well as psychological reactions.

Antioxidant status of patients on peritoneal dialysis: associations with inflammation and glycoxidative stress.

BACKGROUND: Patients on peritoneal dialysis (PD) frequently exhibit oxidant-antioxidant imbalance, advanced glycation end-product overload, and subclinical inflammation but the interrelations between these pathophysiological changes have not been fully elucidated. SUBJECTS AND METHODS: To study possible associations, a cross-sectional study of antioxidant status, glycoxidative stress, and inflammation, using HPLC and ELISA methods, was undertaken in 37 PD patients and age- and sex-matched healthy controls. RESULTS: Plasma ascorbate concentrations were low in patients not taking at least low-dose vitamin C supplements. In patients taking vitamin C supplements, there was a positive relation between ascorbate and pentosidine concentrations. Vitamin E and carotenoid concentrations were comparable between patients and controls, while lycopene and lutein/zeaxanthin concentrations were lower. Interleukin-6, C-reactive protein (CRP), and pentosidine concentrations were elevated in PD patients. beta-Cryptoxanthin, lycopene, and lutein/zeaxanthin concentrations were inversely related to interleukin-6 concentrations. beta-Cryptoxanthin concentrations were also inversely related to CRP concentrations. Pentosidine showed a low dialysate-to-plasma ratio, indicating low peritoneal clearance. Pentosidine concentrations increased with duration of PD therapy, while alpha- and beta-carotene concentrations decreased. Malondialdehyde concentrations were elevated compared to controls but remained within the normal range. Retinol concentrations decreased with PD therapy and were inversely related to interleukin-6 and CRP concentrations. CONCLUSIONS: Low-dose vitamin C supplements and a carotenoid-rich diet should be recommended for PD patients to maintain normal antioxidant status and efficiently counteract the chronic inflammatory response, rather than high doses of vitamin C, which could play a role as a precursor of pentosidine.

Effects of vitamin E depletion/repletion on biomarkers of oxidative stress in healthy aging.

The effects on ex vivo LDL resistance to oxidation and biomarkers of in vivo oxidative stress in response to 3-month dietary vitamin E restriction to 25% of recommended intake and 2-month unrestricted dietary intake and supplementation with 800 IU/d were studied in 100 healthy, nonsmoking 20-75-year-old volunteers. Significant changes in vitamin E status were associated with decreases and increases, respectively, in LDL resistance to oxidation in the depletion and supplementation period and with decreases in lipid peroxidation and oxidative DNA modification in the supplementation period. Healthy aging was not associated with enhanced susceptibility to oxidation in the depletion period.