Chronic treatment with vitamin D lowers arterial blood pressure and reduces endothelium-dependent contractions in the aorta of the spontaneously hypertensive rat

Vitamin D as a modulator of molecular pathways involved in CVDs: Evidence from preclinical studies

Vitamin D deficiency (VDD) is a widespread global health issue, affecting nearly a billion individuals worldwide, and mounting evidence links it to an increased risk of cardiovascular diseases like hypertension, atherosclerosis, and heart failure. The discovery of vitamin D receptors and metabolizing enzymes in cardiac and vascular cells, coupled with experimental studies, underscores the complex relationship between vitamin D and cardiovascular health. This review aims to synthesize and critically evaluate the preclinical evidence elucidating the role of vitamin D in cardiovascular health. We examined diverse preclinical in vitro (cardiomyocyte cell line) models and in vivo models, including knockout mice, diet-induced deficiency, and disease-specific animal models (hypertension, hypertrophy and myocardial infarction). These studies reveal that vitamin D modulates vascular tone, and prevents fibrosis and hypertrophy through effects on major signal transduction pathways (NF-kB, Nrf2, PI3K/AKT/mTOR, Calcineurin/NFAT, TGF-β/Smad, AMPK) and influences epigenetic mechanisms governing inflammation, oxidative stress, and pathological remodeling. In vitro studies elucidate vitamin D's capacity to promote cardiomyocyte differentiation and inhibit pathological remodeling. In vivo studies further uncovered detrimental cardiac effects of VDD, while supplementation with vitamin D in cardiovascular disease (CVD) models demonstrated its protective effects by decreasing inflammation, attenuating hypertrophy, reduction in plaque formation, and improving cardiac function. Hence, this comprehensive review emphasizes the critical role of vitamin D in cardiovascular health and its potential as a preventive/therapeutic strategy in CVDs. However, further research is needed to translate these findings into clinical applications as there are discrepancies between preclinical and clinical studies.

Confronting the global obesity epidemic: investigating the role and underlying mechanisms of vitamin D in metabolic syndrome management

The escalating prevalence of MetS, driven by global obesity trends, underscores the urgent need for innovative therapeutic strategies. To gain a deeper understanding of the therapeutic potential of vitamin D in addressing MetS, we embarked on a targeted literature review that thoroughly examines the scientific underpinnings and pivotal discoveries derived from pertinent studies, aiming to unravel the intricate mechanisms through which vitamin D exerts its effects on MetS and its components. This article explores the multifunctional role of vitamin D in the management of MetS, focusing on its regulatory effects on insulin sensitivity, lipid metabolism, inflammation, and immune response. Through an extensive review of current research, we unveil the complex mechanisms by which vitamin D influences MetS components, highlighting its potential as a therapeutic agent. Our analysis reveals that vitamin D's efficacy extends beyond bone health to include significant impacts on cellular and molecular pathways critical to MetS. We advocate for further research to optimize vitamin D supplementation as a component of precision medicine for MetS, considering the safety concerns related to dosage and long-term use.

Vitamin D and Cardiovascular Diseases: From Physiology to Pathophysiology and Outcomes

Vitamin D is rightly recognized as an essential key factor in the regulation of calcium and phosphate homeostasis, affecting primary adequate bone mineralization. In the last decades, a more complex and wider role of vitamin D has been postulated and demonstrated. Cardiovascular diseases have been found to be strongly related to vitamin D levels, especially to its deficiency. Pre-clinical studies have suggested a direct role of vitamin D in the regulation of several pathophysiological pathways, such as endothelial dysfunction and platelet aggregation; moreover, observational data have confirmed the relationship with different conditions, including coronary artery disease, heart failure, and hypertension. Despite the significant evidence available so far, most clinical trials have failed to prove any positive impact of vitamin D supplements on cardiovascular outcomes. This discrepancy indicates the need for further information and knowledge about vitamin D metabolism and its effect on the cardiovascular system, in order to identify those patients who would benefit from vitamin D supplementation.

Association Between Nutrients and Cardiovascular Diseases

Cardiovascular diseases (CVD) constitute a leading cause of global mortality. Inflammation and oxidative stress are key molecular underpinnings of CVD pathogenesis. This comprehensive review explores the multifaceted role of nutrients in cardiovascular health beyond their impact on cardiac events. The manuscript examines the influence of macronutrients such as fats and carbohydrates, as well as micronutrients including vitamins and folate, on CVD. Additionally, the interplay between dietary supplements and CVD risk reduction is investigated. The purpose of this manuscript is to provide a comprehensive overview of the diverse mechanisms through which nutrients contribute to cardiovascular well-being, addressing both cardioprotective effects and their broader implications. Through an analysis of pertinent studies, we illuminate the complex relationship between nutrition, lifestyle, and cardiovascular health, underscoring the significance of a holistic approach to CVD prevention and management.

Recent Advances in Association Between Vitamin D Levels and Cardiovascular Disorders

PURPOSE OF REVIEW

In this review, we discuss the evidence that vitamin D affects cardiovascular disease through interventional and observational studies and their corresponding association mechanisms. We also highlight the need for further research to definitively conclude clinical recommendations based on preliminary data and determine the extent to which vitamin D levels may impact the incidence and prognosis of major cardiovascular diseases in the future.

RECENT FINDINGS

Cardiovascular disease has long been recognized as the leading cause of morbidity and mortality worldwide, with many risk factors implicated in its pathogenesis. Vitamin D is a risk factor that, despite being known to be crucial for its role in maintaining bone health, also has several extra-skeletal effects due to vitamin D receptors in vascular smooth muscle and cardiomyocytes. Recent studies have documented a significant association between higher vitamin D levels and lower risk of each cardiovascular disease entity; 11 studies between serum vitamin D and heart failure, 7 studies between serum vitamin D and hypertension, 8 studies between serum vitamin D and coronary artery disease, and 5 studies between serum vitamin D and atrial fibrillation. More studies documenting a significant association between increased serum vitamin D and cardiovascular disease are in the context of heart failure compared to hypertension, coronary artery disease, and atrial fibrillation. Conversely, a significant association between increased serum vitamin D and a lower risk of atrial fibrillation is reported in fewer studies compared to the association of vitamin D with other cardiovascular disease entities. Although there is evidence documenting a clear significant association of vitamin D under each category, further research is still needed to definitively conclude the role of vitamin D in cardiovascular disease management.

Role of Vitamin D Deficiency in the Pathogenesis of Cardiovascular and Cerebrovascular Diseases

Deficiency in vitamin D (VitD), a lipid-soluble vitamin and steroid hormone, affects approximately 24% to 40% of the population of the Western world. In addition to its well-documented effects on the musculoskeletal system, VitD also contributes importantly to the promotion and preservation of cardiovascular health via modulating the immune and inflammatory functions and regulating cell proliferation and migration, endothelial function, renin expression, and extracellular matrix homeostasis. This brief overview focuses on the cardiovascular and cerebrovascular effects of VitD and the cellular, molecular, and functional changes that occur in the circulatory system in VitD deficiency (VDD). It explores the links among VDD and adverse vascular remodeling, endothelial dysfunction, vascular inflammation, and increased risk for cardiovascular and cerebrovascular diseases. Improved understanding of the complex role of VDD in the pathogenesis of atherosclerotic cardiovascular diseases, stroke, and vascular cognitive impairment is crucial for all cardiologists, dietitians, and geriatricians, as VDD presents an easy target for intervention.

Endothelial dysfunction: developmental mechanisms and therapeutic strategies

Introduction: Every year the importance of the normal functioning of the endothelial layer of the vascular wall in maintaining the health of the body becomes more and more obvious.

The physiological role of the endothelium: The endothelium is a metabolically active organ actively involved in the regulation of hemostasis, modulation of inflammation, maintenance of hemovascular homeostasis, regulation of angiogenesis, vascular tone, and permeability.

Risk factors for the development of endothelial dysfunction: Currently, insufficient bioavailability of nitric oxide is considered the most significant risk factor for endothelial dysfunction.

Mechanisms of development of endothelial dysfunction: The genesis of endothelial dysfunction is a multifactorial process. Among various complex mechanisms, this review examines oxidative stress, inflammation, hyperglycemia, vitamin D deficiency, dyslipidemia, excess visceral fat, hyperhomocysteinemia, hyperuricemia, as well as primary genetic defect of endotheliocytes, as the most common causes in the population underlying the development of endothelial dysfunction.

Markers of endothelial dysfunction in various diseases: This article discusses the main biomarkers of endothelial dysfunction currently used, as well as promising biomarkers in the future for laboratory diagnosis of this pathology.

Therapeutic strategies: Therapeutic approaches to the endothelium in order to prevent or reduce a degree of damage to the vascular wall are briefly described.

Conclusion: Endothelial dysfunction is a typical pathological process involved in the pathogenesis of many diseases. Thus, pharmacological agents with endothelioprotective properties can provide more therapeutic benefits than a drug without such an effect.

Modulation of cardiometabolic risk and CardioRenal syndrome by oral vitamin D3 supplementation in Black and White Southern Sahara residents with chronic kidney disease Stage 3: focus on racial and ethnic disparities

OBJECTIVES

Several studies have shown that cholecalciferol supplementation (25OHD-S) in chronic kidney disease (CKD) improves kidney injury by reducing fibrosis-related vascular calcification and declining apoptosis-linked nephron damage.

METHODS

The oral 25OHD-S was evaluated in 60,000 IU/month/36 weeks versus in 2000 IU/d/24 weeks in CKD Stage 3 with serum 25OHD level < 20 ng/mL. The study was undertaken on 156 black subjects and 150 white subjects Southern Sahara (SS). All biomarkers of cardiometabolic (CMet) and cardiorenal (CRenal) syndrome, Renin-angiotensin-aldosterone system (RAAS) profile, secondary hyperparathyroidism (SHPT), N-terminal pro B-type natriuretic peptide (NT-proBNP), Troponin T (cTnT) and atherogenicity risk were assessed by biochemical methods. Estimate glomerular filtration rate (eGFR) by chronic CKD-EPI equation formula. Total serum vitamin D by liquid chromatography-tandem mass spectrometry (MS).

RESULTS

Vitamin D deficiency alters in the same manner CMet, CRenal, and others biomarkers in both groups SS; however, these disorders are more acute in blacks compared to whites SS. Oral 25OHD-S a highlighted improvement of eGFR drop, SHPT decrease, decline proteinuria, and cardiac failure risk (NT-proBNP and cTnT) attenuation. Concomitantly, 25OHD-S normalizes Renin, Aldosterone, and Angiotensin System (RAAS) activity. Nevertheless, homocysteine and Lp (a) do not modulate by 25OHD-S.

CONCLUSIONS

The oral vitamin D3 supplementation, according the dose, and the treatment duration does not like in black-skinned people versus to white-skinned inhabitants, while the 02 groups are native to the same Saharan environment. It emerge that a high intermittent dose through an extensive supplementation (60,000 IU/36 weeks) was more effective in black subjects. At opposite, a lower dose during a short period supplementation is sufficient (2000 IU/24 weeks) in white subjects.

Comparing the Evidence from Observational Studies and Randomized Controlled Trials for Nonskeletal Health Effects of Vitamin D

Although observational studies of health outcomes generally suggest beneficial effects with, or following, higher serum 25-hydroxyvitamin D [25(OH)D] concentrations, randomized controlled trials (RCTs) have generally not supported those findings. Here we review results from observational studies and RCTs regarding how vitamin D status affects several nonskeletal health outcomes, including Alzheimer's disease and dementia, autoimmune diseases, cancers, cardiovascular disease, COVID-19, major depressive disorder, type 2 diabetes, arterial hypertension, all-cause mortality, respiratory tract infections, and pregnancy outcomes. We also consider relevant findings from ecological, Mendelian randomization, and mechanistic studies. Although clear discrepancies exist between findings of observational studies and RCTs on vitamin D and human health benefits these findings should be interpreted cautiously. Bias and confounding are seen in observational studies and vitamin D RCTs have several limitations, largely due to being designed like RCTs of therapeutic drugs, thereby neglecting vitamin D's being a nutrient with a unique metabolism that requires specific consideration in trial design. Thus, RCTs of vitamin D can fail for several reasons: few participants' having low baseline 25(OH)D concentrations, relatively small vitamin D doses, participants' having other sources of vitamin D, and results being analyzed without consideration of achieved 25(OH)D concentrations. Vitamin D status and its relevance for health outcomes can usefully be examined using Hill's criteria for causality in a biological system from results of observational and other types of studies before further RCTs are considered and those findings would be useful in developing medical and public health policy, as they were for nonsmoking policies. A promising approach for future RCT design is adjustable vitamin D supplementation based on interval serum 25(OH)D concentrations to achieve target 25(OH)D levels suggested by findings from observational studies.

Is Vitamin D Supplementation an Effective Treatment for Hypertension?

Purpose of the Review

Results from epidemiological studies suggest that vitamin D (VD) deficiency (VDD) may be a cause of hypertension (HTN). However, the results of randomized clinical trials (RCTs) designed to address the impact of VD supplementation on reducing blood pressure (BP) remain equivocal. To determine whether VD might serve as a beneficial treatment option for a specific subset of hypertensive patients, we performed a stratified analysis of RCT data and addressed problems associated with some methodological issues.

Recent Findings

HTN is caused by multiple factors. VDD may be one of the factors contributing to the development of this disorder. There are more than 70 RCTs that examined the impact of VD supplementation on BP. These RCTs can be classified into four groups based on their respective study populations, including participants who are (1) VD-sufficient and normotensive, (2) VD-deficient and normotensive, (3) VD-sufficient and hypertensive, and (4) VD-deficient and hypertensive.

Summary

Our evaluation of these studies demonstrates that VD supplementation is ineffective when used to reduce BP in VD-sufficient normotensive subjects. VD supplementation for five years or more may reduce the risk of developing HTN specifically among those with VDD. Interestingly, findings from 12 RCTs indicate that daily or weekly supplementation, as opposed to large bolus dosing, results in the reduction of BP in VD-deficient hypertensive patients. Our ongoing research focused on elucidating the mechanisms of VDD-induced HTN will ultimately provide evidence to support the development of etiology-specific prevention and treatment strategies focused on HTN in the VD-deficient population.

Astronauts Plasma-Derived Exosomes Induced Aberrant EZH2-Mediated H3K27me3 Epigenetic Regulation of the Vitamin D Receptor

There are unique stressors in the spaceflight environment. Exposure to such stressors may be associated with adverse effects on astronauts' health, including increased cancer and cardiovascular disease risks. Small extracellular vesicles (sEVs, i.e., exosomes) play a vital role in intercellular communication and regulate various biological processes contributing to their role in disease pathogenesis. To assess whether spaceflight alters sEVs transcriptome profile, sEVs were isolated from the blood plasma of 3 astronauts at two different time points: 10 days before launch (L-10) and 3 days after return (R+3) from the Shuttle mission. AC16 cells (human cardiomyocyte cell line) were treated with L-10 and R+3 astronauts-derived exosomes for 24 h. Total RNA was isolated and analyzed for gene expression profiling using Affymetrix microarrays. Enrichment analysis was performed using Enrichr. Transcription factor (TF) enrichment analysis using the ENCODE/ChEA Consensus TF database identified gene sets related to the polycomb repressive complex 2 (PRC2) and Vitamin D receptor (VDR) in AC16 cells treated with R+3 compared to cells treated with L-10 astronauts-derived exosomes. Further analysis of the histone modifications using datasets from the Roadmap Epigenomics Project confirmed enrichment in gene sets related to the H3K27me3 repressive mark. Interestingly, analysis of previously published H3K27me3-chromatin immunoprecipitation sequencing (ChIP-Seq) ENCODE datasets showed enrichment of H3K27me3 in the VDR promoter. Collectively, our results suggest that astronaut-derived sEVs may epigenetically repress the expression of the VDR in human adult cardiomyocytes by promoting the activation of the PRC2 complex and H3K27me3 levels.

Serum Vitamin D Level and Erectile Dysfunction in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

INTRODUCTION

A few studies involved the relationship between vitamin D and diabetes mellitus (DM) with erectile dysfunction (ED), and no meta-analysis was conducted to pool these data. The main purpose of our study was to examine the changes in serum vitamin D levels in patients with DM combined with ED.

METHODS

An extensive search was performed, including the following words: "erectile dysfunction," "diabetes," and "vitamin D." Databases, including Cochrane Library, PubMed, and Web of Science, were retrieved to identify studies published up to September 30, 2021. Four studies were eligible for our meta-analysis.

RESULTS

The weighted mean difference and their corresponding 95% confidence intervals were calculated to the data we selected. The results showed that the level of vitamin D in DM with ED was significantly lower (12.5 nmol/mL) than patients with diabetes alone (p = 0.002).

CONCLUSION

Our novel meta-analysis suggests that vitamin D may be a risk factor for DM with ED, which can provide a new idea for the treatment and prevention of DM with ED.

Calcitriol ameliorates damage in high-salt diet-induced hypertension: Evidence of communication with the gut-kidney axis

Several studies have established a link between high-salt diet, inflammation, and hypertension. Vitamin D supplementation has shown anti-inflammatory effects in many diseases; gut microbiota is also associated with a wide variety of cardiovascular diseases, but potential role of vitamin D and gut microbiota in high-salt diet-induced hypertension remains unclear. Therefore, we used rats with hypertension induced by a high-salt diet as the research object and analyzed the transcriptome of their tissues (kidney and colon) and gut microbiome to conduct an overall analysis of the gut-kidney axis. We aimed to confirm the effects of high salt and calcitriol on the gut-kidney immune system and the composition of the intestinal flora. We demonstrate that consumption of a high-salt diet results in hypertension and inflammation in the colon and kidney and alteration of gut microbiota composition and function. High-salt diet-induced hypertension was found to be associated with seven microbial taxa and mainly associated with reduced production of the protective short-chain fatty acid butyrate. Calcitriol can reduce colon and kidney inflammation, and there are gene expression changes consistent with restored intestinal barrier function. The protective effect of calcitriol may be mediated indirectly by immunological properties. Additionally, the molecular pathways of the gut microbiota-mediated blood pressure regulation may be related to circadian rhythm signals, which needs to be further investigated. An innovative association analysis of the microbiota may be a key strategy to understanding the association between gene patterns and host.

Vitamin D Deficiency Reduces Vascular Reactivity of Coronary Arterioles in Male Rats

BACKGROUND

Vitamin D deficiency (VDD) may be considered an independent cardiovascular (CV) risk factor, and it is well known that CV risk is higher in males. Our goal was to investigate the pharmacological reactivity and receptor expression of intramural coronary artery segments of male rats in cases of different vitamin D supply.

METHODS

Four-week-old male Wistar rats were divided into a control group (n = 11) with optimal vitamin D supply (300 IU/kgbw/day) and a VDD group (n = 11, <0.5 IU/kgbw/day). After 8 weeks of treatment, intramural coronary artery segments were microprepared, their pharmacological reactivity was examined by in vitro microangiometry, and their receptor expression was investigated by immunohistochemistry.

RESULTS

Thromboxane A2 (TXA2)-agonist induced reduced vasoconstriction, testosterone (T) and 17-β-estradiol (E2) relaxations were significantly decreased, a significant decrease in thromboxane receptor (TP) expression was shown, and the reduction in estrogen receptor-α (ERα) expression was on the border of significance in the VDD group.

CONCLUSIONS

VD-deficient male coronary arteries showed deteriorated pharmacological reactivity to TXA2 and sexual steroids (E2, T). Insufficient vasoconstrictor capacity was accompanied by decreased TP receptor expression, and vasodilator impairments were mainly functional. The decrease in vasoconstrictor and vasodilator responses results in narrowed adaptational range of coronaries, causing inadequate coronary perfusion that might contribute to the increased CV risk in VDD.

The Relationship Between Vitamin D Status and Cardiovascular Diseases

With cardiovascular conditions being a leading cause of mortality and morbidity globally, several studies have identified that there is an important correlation between the level of Vitamin D and cardiovascular diseases, including an increased risk of hypertension, heart failure, and coronary artery diseases. Current published studies are in the form of both in vivo and in vitro studies and they primarily showed the evidence of how Vitamin D can downregulate Renin-Angiotensin-Aldosterone system activity and therefore providing a cardioprotective role. Nevertheless, most of these studies are observational, and there yet to be large-scale randomized controlled trials which would increase the evidence of the findings.This review aims to capture the current evidence of Vitamin D as a metabolite which is critical in reducing cardiovascular conditions and the possible physiological pathways that it works via.

Early-life persistent vitamin D deficiency-induced cardiovascular dysfunction in mice is mediated by transient receptor potential C channels

BACKGROUND

Studies indicate that chronic vitamin D deficiency (VDD) may predispose to hypertension, yet, there is very little data characterizing its direct cardiac effects. Vitamin D modulates the function of transient receptor potential C cation channels (TRPC), which is a mechanosensitive cation channel that plays a role in cardiac slow-force responses to hemodynamic changes. The purpose of this study was to determine the cardiac effects of VDD and the potential role of TRPC.

METHODS

Three-week old mice were placed on a VDD or normal diet (ND) for 19 weeks. Mice were then implanted with radiotelemeters for the measurement of heart rate (HR) and heart rate variability (HRV), while a separate group was anesthetized to measure blood pressure (BP) and left ventricular function using an intraventricular probe. Animals were treated with a TRPC antagonist or vehicle after which they were challenged with dobutamine to measure cardiac responses.

RESULTS

VDD mice had significantly increased BP (72 ± 3 mmHg vs. 62 ± 2 mmHg) and left ventricular pressure (LVP) (84.6 ± 0.8 mmHg vs. 78.2 ± 2.0 mmHg), and decreased cardiac contractility (-3 % vs. + 11 %) and HR response (+8 % vs. + 13 %) to dobutamine when compared to ND. These responses were blocked by the TRPC antagonist. HRV decreased with increasing dobutamine doses in ND but not VDD mice, however, the antagonist had no effect.

CONCLUSION

VDD increases BP and alters cardiac mechanical function in mice, the latter appears to be mediated by TRPC, in particular TRPC6. Although the cardiac effects might be due to increased BP, it is likely that VDD also affects the function of the heart directly. This is the first study to demonstrate the potentially deleterious effects of VDD on cardiac function and the role of TRPC6 in this response.

Calcitriol inhibits COX-1 and COX-2 expressions of renal vasculature in hypertension: Reactive oxygen species involved?

Vitamin D modulates about 3% human gene transcription besides the classical action on calcium/phosphorus homeostasis. The blood pressure-lowing and other protective action on cardiovascular disease have been reported. The present study aims to examine whether COX-1 and COX-2 were implicated in endothelial dysfunction in hypertension and calcitriol, an active form of vitamin D preserved endothelial function through regulating COX expression. Isometric study demonstrated the impaired endothelium-dependent relaxation (EDR) in renal arteries from spontaneously hypertensive rats were reversed by 12 h-calcitriol treatment and COX-1 and COX-2 inhibitors. Combined uses of COX-1 and COX-2 inhibitor induced more improved relaxations. Exaggerated expressions of COX-1 and COX-2 in renal artery from SHR were inhibited by 12 h-administration of calcitriol, NADPH oxidase inhibitor DPI, or reactive oxygen species (ROS) scavenger tempol. Furthermore, in normotensive WKY rats, calcitriol prevents against the blunted EDR in renal arteries by 12 h-Ang II exposure, with similar improvements by COX-1 and COX-2 inhibitors. Accordingly, increased COX-1 and COX-2 expressions by Ang II exposure were corrected by losartan, DPI, or tempol. Studies on human renal artery also revealed the beneficial action of calcitriol is mediated by suppressing COX-1 and COX-2 expressions, dependent on vitamin D receptor (VDR) activation. Taken together, our findings showed that COX-1 and COX-2 are positively involved in the renovascular dysfunction in hypertension and via VDR, calcitriol benefits renovasular function by suppressing COX-1 and COX-2 expressions. Furthermore, ROS is involved in the COX-1 and COX-2 up-regulations of renal arteries, maybe serving as a mediator in the inhibitory action of calcitriol on COX expression.

Novel predictive risk factor of erectile dysfunction: Serum 25-hydroxy vitamin D

The present study aimed to investigate the association between the severity of erectile dysfunction (ED) and serum 25-hydroxy vitamin D. It also sought to determine the cut-off level of serum 25-hydroxy vitamin D for ED. This study included 130 men who had ED between 2018 and 2019. Patients were divided into three groups according to their scores on the international index of erectile function-5 (IIEF-5) Turkish validated short form questionnaire. The serum 25-hydroxy vitamin D results were compared between the groups. The mean age of the patients was 49.28 ± 13.62 years. Groups 1, 2 and 3 included 44 (33.8%) patients with severe ED, 56 (43.1%) patients with moderate ED and 30 (23.1%) patients with mild ED, respectively. Statistical significance was observed between the groups and serum 25-hydroxy vitamin D levels. A positive correlation was detected between the IIEF-5 scores, serum testosterone and serum 25-hydroxy vitamin D levels. A cut-off level for serum 25-hydroxy vitamin D was calculated as 27.32 ng/ml. During multivariate analysis, we found that serum 25-hydroxy vitamin D levels were independent prognostic risk factors for decreased IIEF-5 scores. Decreased serum 25-hydroxy vitamin D levels were associated with decreased IIEF-5 scores. Therefore, vitamin D replacement therapy may improve symptoms.

Vitamin D and Cardiovascular Disease, with Emphasis on Hypertension, Atherosclerosis, and Heart Failure

Vitamin D deficiency is the most common nutritional deficiency, affecting almost one billion people worldwide. Vitamin D is mostly known for its role in intestinal calcium absorption and bone mineralization. However, the observation of seasonal changes in blood pressure and the subsequent identification of vitamin D receptor (VDR) and 1α-hydroxylase in cardiomyocytes, as well as endothelial and vascular smooth muscle cells, implicated a role of vitamin D in the cardiovascular system. Animal studies provided compelling evidence that vitamin D signaling is essential for cardiovascular integrity, especially for the regulation of vascular tone and as an antifibrotic and antihypertrophic signaling pathway in the heart. In addition, observational studies reported an association between vitamin D deficiency and risk of hypertension, atherosclerosis, and heart failure. However, recent clinical intervention studies failed to prove the causal relationship between vitamin D supplementation and beneficial effects on cardiovascular health. In this review, we aim to highlight our current understanding of the role of vitamin D in the cardiovascular system and to find potential explanations for the large discrepancies between the outcome of experimental studies and clinical intervention trials.

Investigating the Relationship the Severity of Coronary Artery Disease with Serum Levels of Vitamin D in Men after Eliminating the Effect of Diet

Background:

Coronary artery disease (CAD) is one of the most common cardiovascular diseases that can lead to mortality, inability, and lower productivity levels.

Objective:

The aim of this study was to determine the relationship between serum vitamin D level and cardiovascular risk factors and the severity of CAD after determining and eliminating the confounding effects of dietary patterns in male patients undergoing angiography.

Methods:

This descriptive-analytic study was carried out on 132 men undergoing angiography during 2017 and 2018. To this end, food frequency questionnaire (FFQ) and physical activity questionnaire (PAQ) were completed for the patients. Fasting blood sugar (FBS), triglyceride, total cholesterol, HDL-C, LDL-C and vitamin D levels were also investigated.

Results:

Serum vitamin D levels significantly decreased with an increase in CAD severity (p=0.001). Also, low serum levels led to the highest severity of CAD (p=0.005). However, there was no significant difference between patients with vitamin D deficiency with different degrees of CAD (p=0.084). Also, the highest percentage of individuals with normal serum levels of vitamin D was observed in the group without any blocked blood arteries (normal) (p=0.023).

Conclusion:

This study shows an inverse relationship between serum 25(OH) D level and the severity of CAD. Our data show that vitamin D plays an important role in preventing CAD. These findings could help design prospective studies and clinical trials on a wider scale to investigate the effects of vitamin D interventions in preventing the development of CAD.

Dietary supplementation of 25-hydroxycholecalciferol improves cardiac function and livability in broiler breeder hens-amelioration of blood pressure and vascular remodeling

A supplement of 69 μg 25-hydroxycholecalciferol (25-OH-D3)/kg feed suppressed the mortality in feed-restricted broiler breeder hens and in hens allowed ad libitum feed intake (Ad-hens) in a feeding trial from age 26 to 60 wk. Outcomes for the mechanisms found that 25-OH-D3 relieved systemic hypoxia, pathological cardiac remodeling and arrhythmias, and hepatopathology to improve hens' livability. In the study, we further evaluated the effect of 25-OH-D3 on blood pressure and vascular remodeling relative to cardiac pathogenesis of sudden death (SD). Ad libitum feed intake increased mechanical loading and contributed to maladaptive cardiac hypertrophy as evidenced by consistently elevated peripheral arterial blood pressure in Ad-hens before SD (P < 0.05). In planned longitudinal measurements, Ad-hens also showed higher right ventricle systolic pressure and right ventricle diastolic pressure (RVDP) (P < 0.05). Supplemental 25-OH-D3 relieved peripheral hypertension and prevented time-dependent increases of RVDP in Ad-hens through the renin-angiotensin system and circulating nitric oxide availability and by regulating vascular remodeling including elastin/collagen ratio and smooth muscle cell proliferation in the pulmonary artery for improved elasticity/stiffness (P < 0.05). The antihypertensive effect via the renin-angiotensin system and nitric oxide regulation in respect to heart rate and arrhythmias by 25-OH-D3 were further confirmed in 51 week-old feed-restricted broiler breeder hens challenged with salt loading for 5 wk. Despite feed restriction, the most feed-efficient hens of feed-restricted groups also exhibited cardiac pathological hypertrophy, in conjunction with higher right ventricle systolic pressure, RVDP, plasma nitric oxide levels, and more dramatic arterial remodeling (P < 0.05). These results suggest that peripheral and pulmonary hypertension are the key drivers of SD and that 25-OH-D3 is an effective antihypertensive supplement to alleviate cardiac pathogenesis and improve livability in broiler breeder hens.

Calcitriol ameliorated autonomic dysfunction and hypertension by down-regulating inflammation and oxidative stress in the paraventricular nucleus of SHR

The hypothalamic paraventricular nucleus (PVN) plays crucial roles in central cardiovascular regulation. Increasing evidence in humans and rodents shows that vitamin D intake is important for achieving optimal cardiovascular function. The purpose of this study was to investigate whether calcitriol, an active form of vitamin D, improves autonomic and cardiovascular function in hypertensive rats and whether PVN oxidative stress and inflammation are involved in these beneficial effects. Male spontaneously hypertensive rats (SHR) and normotensive control Wistar Kyoto (WKY) rats were treated with either calcitriol (40 ng/day) or vehicle (0.11 μL/h) through chronic PVN infusion for 4 weeks. Blood pressure and heart rate were recorded continuously by radiotelemetry. PVN tissue, heart and plasma were collected for molecular and histological analysis. Compared to WKY rats, SHR exhibited increased systolic blood pressure, sympathetic drive, and cardiac hypertrophy and remodeling. These were associated with higher mRNA and protein expression levels of high mobility box 1 (HMGB1), receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), proinflammatory cytokines, NADPH oxidase subunit in the PVN. In addition, increased norepinephrine in plasma, elevated reactive oxygen species levels and activation of microglia in the PVN were also observed in SHR. Chronic calcitriol treatment ameliorated these changes but not in WKY rats. Our results demonstrate that chronic infusion of calcitriol in the PVN ameliorates hypertensive responses, sympathoexcitation and retains cardiovascular function in SHR. Reduced inflammation and oxidative stress within the PVN are involved in these calcitriol-induced effects.

Serum Vitamin D, Sleep Pattern and Cardiometabolic Diseases: Findings from the National Health and Nutrition Examination Survey

OBJECTIVE

Although poor sleep health and vitamin D deficiency may be associated with diabetes and hypertension, whether this association shows a trend depending on vitamin D concentration is unclear.

SUBJECTS AND METHODS

We analyzed data from 10,742 participants (4997 men) from the 2007-2014 National Health and Nutrition Examination Survey. Abnormal sleep pattern (ie, short sleep duration, sleep complaint, and/or sleep disorder), lifestyle factors, serum vitamin D level, and the status of diabetes and hypertension were assessed. Logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Serum vitamin D significantly interacted with short sleep duration and abnormal sleep pattern (both p = 0.003) on the association with diabetes in men. Short sleep duration (OR: 1.82, 95% CI = 1.29, 2.57) and abnormal sleep pattern (OR: 1.95, 95% CI = 1.38, 2.77) were associated with diabetes in men with serum vitamin D of >75 nmol/L. Serum vitamin D significantly interacted with sleep complaint on the association with hypertension in men and women (both p < 0.05). The magnitude of association between sleep complaint and hypertension in men was stronger when serum vitamin D level was <50 nmol/L (OR: 2.26, 95% CI = 1.57, 3.25) than when the level was >75 nmol/L (OR: 1.28, 95% CI = 0.90, 1.83). Similarly, the magnitude of association between sleep complaint and hypertension in women was stronger when serum vitamin D level was <50 nmol/L (OR: 2.09, 95% CI = 1.53, 2.86) than when the level was >75 nmol/L (OR: 1.64, 95% CI = 0.98, 2.72). No significant interactions were observed between serum vitamin D level and other sleep variables.

CONCLUSION

Abnormal sleep pattern is associated with a high risk of diabetes and hypertension. The relationship between sleep complaint and hypertension may be strong in people with vitamin D deficiency, and this observation should be verified by prospective studies.

Vitamin D receptor activation regulates microglia polarization and oxidative stress in spontaneously hypertensive rats and angiotensin II-exposed microglial cells: Role of renin-angiotensin system

Hypertension is one of the major predisposing factors for neurodegenerative disease characterized with activated renin-angiotensin system (RAS) in both periphery and brain. Vitamin D (VitD) is recently recognized as a pleiotropic hormone with strong neuroprotective properties. While multiple lines of evidence suggest that VitD can act on RAS, the evidence concerning the crosstalk between VitD and RAS in the brain is limited. Therefore, this study aims to evaluate whether VitD can modulate brain RAS to trigger neuroprotective actions in the brain of spontaneously hypertensive rats (SHR). Our data showed that calcitriol treatment induced VDR expression and inhibited neural death in the prefrontal cortex of SHR. Sustained calcitriol administration also inhibited microglia M1 polarization, but enhanced M2 polarization, accompanied with decreased expression of proinflammatory cytokines. We then further explored the potential mechanisms and showed that SHR exhibited overactivated classical RAS with increased expression of angiotensin II (Ang II) receptor type 1 (AT1), angiotensin converting enzyme (ACE) and Ang II production, whereas the counteracting arm of traditional RAS, ACE2/Ang(1-7)/MasR, was impaired in the SHR brain. Calcitriol nonsignificantly suppressed AT1 and ACE but markedly reduced Ang II formation. Intriguingly, calcitriol exerted pronouncedly impact on ACE2/Ang(1-7)/MasR axis with enhanced expression of ACE2, MasR and Ang(1-7) generation. Meanwhile, calcitriol ameliorated the overactivation of NADPH-oxidase (Nox), the downstream of RAS, in SHR, and also mitigated oxidative stress. In microglial (BV2) cells, we further found that calcitriol induced ACE2 and MasR with no significant impact on ACE and AT1. In accordance, calcitriol also attenuated Ang II-induced Nox activation and ROS production, and shifted the microglia polarization from M1 to M2 phenotype. However, co-treatment with A779, a specific MasR antagonist, abrogated the antioxidant and neuroimmune modulating actions of VitD. These findings strongly indicate the involvement of ACE2/Ang(1-7)/MasR pathway in the neuroprotective mechanisms of VitD in the hypertensive brain.

Vitamin D supplementation alters the expression of genes associated with hypertension and did not induce DNA damage in rats

Vitamin D3 deficiency has been correlated with altered expression of genes associated with increased blood pressure (BP); however, the role of vitamin D3 supplementation in the genetic mechanisms underlying hypertension remains unclear. Thus, the aim of this study was investigate the consequences of vitamin D3 supplemented (10,000 IU/kg) or deficient (0 IU/kg) diets on regulation of expression of genes related to hypertension pathways in heart cells of spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) controls. An additional aim was to assess the impact of vitamin D3 on DNA damage and oxidative stress markers. The gene expression profiles were determined by PCR array, DNA damage was assessed by an alkaline comet assay, and oxidative stress markers by measurement of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels. In SHR rats data showed that the groups of genes most differentially affected by supplemented and deficient diets were involved in BP regulation and renin-angiotensin system. In normotensive WKY controls, the profile of gene expression was similar between the two diets. SHR rats were more sensitive to changes in gene expression induced by dietary vitamin D3 than normotensive WKY animals. In addition to gene expression profile, vitamin D3 supplemented diet did not markedly affect DNA or levels of TBARS and GSH levels in both experimental groups. Vitamin D3 deficient diet produced lipid peroxidation in SHR rats. The results of this study contribute to a better understanding of the role of vitamin D3 in the genetic mechanisms underlying hypertension. Abbreviations: AIN, American Institute of Nutrition; EDTA, disodium ethylenediaminetetraacetic acid; GSH, glutathione; PBS, phosphate buffer solution; SHR, spontaneously hypertensive rats; TBARS, thiobarbituric acid reactive substances; WKY, Wistar Kyoto.

1.25 Dihydroxyvitamin D3 Attenuates Hypertrophy Markers in Cardiomyoblast H9c2 Cells: Evaluation of Sirtuin3 mRNA and Protein Level

Background: The cellular and molecular mechanisms of cardioprotective effects of Vitamin D are poorly understood. Given the essential role of sirtuin-3 (SIRT3) as an endogenous negative regulator of cardiac hypertrophy, this study was designed to investigate the effect of 1, 25-dihydroxyvitamin D3 (calcitriol) on hypertrophy markers and SIRT3 mRNA and protein levels following angiotensin II induced - hypertrophy in cardiomyoblast H9c2 cells. Methods: Rat cardiomyoblast H9c2 cells were treated for 48 hr with angiotensin II alone (Ang group) or in combination with 1, 10 and 100 nM of calcitriol (C + Ang groups). Intact cells served as control (Ctl). The cell area was measured using methylene blue staining. Atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and SIRT3 transcription levels were measured by real time RT-PCR. SIRT3 protein expression was evaluated using western blot technique. Results: The results showed that in Ang group cell size was increase by 128.4 ± 15% (P < 0.001 vs. Ctl) whereas in C100 + Ang group it was increased by 21.3 ± 6% (P < 0.001 vs. Ang group). Calcitriol pretreatment decreased ANP mRNA level significantly (P < 0.05) in comparison with Ang group (Ang: 75.5 ± 15%, C100 + Ang: 19.2 ± 9%). There were no significant differences between Ang group and cells pretreated with 1 and 10 nM of calcitriol. SIRT3 at mRNA and protein levels did not change significantly among the experimental groups. Conclusions: In conclusion, pretreatment with calcitriol (100 nM) prevents Ang II-induced hypertrophy in cardiomyoblast H9c2 cells. This probably occurs through other pathways except SIRT3 upregulation.

Vitamin D and Calcimimetics in Cardiovascular Disease

Cardiovascular disease has earned its place as one of the leading noncommunicable diseases that has become a modern-day global epidemic. The increasing incidence and prevalence of chronic kidney disease (CKD) has added to this enormous burden, given that CKD is now recognized as an established risk factor for accelerated cardiovascular disease. In fact, cardiovascular disease remains the leading cause of death in the CKD population, with significant prognostic implications. Alterations in vitamin D levels as renal function declines has been linked invariably to the development of cardiovascular disease beyond a mere epiphenomenon, and has become an important focus in recent years in our search for new therapies. Another compound, cinacalcet, which belongs to the calcimimetic class of agents, also has taken center stage over the past few years as a potential cardiovasculoprotective agent. However, given limited well-designed randomized trials to inform us, our clinical practice for the management of cardiovascular disease in CKD has not been adequately refined. This article considers the biological mechanisms, regulation, and current experimental, clinical, and trial data available to help guide the therapeutic use of vitamin D and calcimimetics in the setting of CKD and cardiovascular disease.

The Antioxidant Therapy: New Insights in the Treatment of Hypertension

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play a key role in the regulation of the physiological and pathological signaling within the vasculature. In physiological conditions, a delicate balance between oxidants and antioxidants protects cells from the detrimental effects of ROS/RNS. Indeed, the imbalance between ROS/RNS production and antioxidant defense mechanisms leads to oxidative and nitrosative stress within the cell. These processes promote the vascular damage observed in chronic conditions, such as hypertension. The strong implication of ROS/RNS in the etiology of hypertension suggest that antioxidants could be effective in the treatment of this pathology. Indeed, in animal models of hypertension, the overexpression of antioxidants and the genetic modulation of oxidant systems have provided an encouraging proof of concept. Nevertheless, the translation of these strategies to human disease did not reach the expected success. This could be due to the complexity of this condition, whose etiology depends on multiple factors (smoking, diet, life styles, genetics, family history, comorbidities). Indeed, 95% of reported high blood pressure cases are deemed "essential hypertension," and at the molecular level, oxidative stress seems to be a common feature of hypertensive states. In this scenario, new therapies are emerging that could be useful to reduce oxidative stress in hypertension. It is now ascertained the role of Vitamin D deficiency in the development of essential hypertension and it has been shown that an appropriate high dose of Vitamin D significantly reduces blood pressure in hypertensive cohorts with vitamin D deficiency. Moreover, new drugs are emerging which have both antihypertensive action and antioxidant properties, such as celiprolol, carvedilol, nebivolol. Indeed, besides adrenergic desensitization, these kind of drugs are able to interfere with ROS/RNS generation and/or signaling, and are therefore considered promising therapeutics in the management of hypertension. In the present review we have dealt with the effectiveness of the antioxidant therapy in the management of hypertension. In particular, we discuss about Vitamin D and anti-hypertensive drugs with antioxidant properties.

Health Risks of Hypovitaminosis D: A Review of New Molecular Insights

Hypovitaminosis D has become a pandemic, being observed in all ethnicities and age groups worldwide. Environmental factors, such as increased air pollution and reduced ultraviolet B (UVB) irradiation, as well as lifestyle factors, i.e., decreased outdoor activities and/or poor intake of vitamin D-rich food, are likely involved in the etiology of a dramatic reduction of vitamin D circulating levels. The insufficiency/deficiency of vitamin D has long been known for its association with osteoporosis and rickets. However, in the last few decades it has become a serious public health concern since it has been shown to be independently associated with various chronic pathological conditions such as cancer, coronary heart disease, neurological diseases, type II diabetes, autoimmune diseases, depression, with various inflammatory disorders, and with increased risk for all-cause mortality in the general population. Prevention strategies for these disorders have recently involved supplementation with either vitamin D2 or vitamin D3 or their analogs at required daily doses and tolerable upper-limit levels. This review will focus on the emerging evidence about non-classical biological functions of vitamin D in various disorders.

Effects of Different Dietary Interventions on Calcitriol, Parathyroid Hormone, Calcium, and Phosphorus: Results from the DASH Trial

The "Dietary Approaches to Stop Hypertension" (DASH) diet, rich in fiber and low-fat dairy, effectively lowers blood pressure. DASH's effect on calcitriol and other markers of bone-mineral metabolism is unknown. This secondary analysis of the DASH trial aimed to determine the effect of dietary patterns on blood concentrations of calcitriol, parathyroid hormone (PTH), ionized calcium, and urinary excretion of calcium and phosphorus. Outcomes were available in 334 participants in the trial. After a 3-week run-in on the control diet, participants were randomized to control, fruits and vegetables (F&amp;V), or DASH diets. Outcomes were assessed at the end of run-in, and during the last week of the intervention period. Mean age of participants was 45.7 ± 10.7 years, 46% female, and 57% African-American. Mean ± Standard Deviation(SD) baseline serum concentrations of calcitriol, PTH, and ionized calcium were 37.8 ± 9.2 pg/mL, 46.1 ± 18.5 pg/mL and 5.2 ± 0.23 mg/dL, respectively. Mean (±SD) urinary calcium and phosphorus excretions were 150.1 ± 77.8 and 708.0 ± 251.8 mg/24 h, respectively. Compared with control, DASH reduced calcitriol -3.32 pg/mL (p = 0.004). Otherwise, there was no significant effect on other biomarkers. DASH lowered serum calcitriol perhaps more among African-Americans. These results raise important questions about the interpretation and clinical significance of low calcitriol concentrations in the setting of recommended diets.

Nanomedical studies of the restoration of nitric oxide/peroxynitrite balance in dysfunctional endothelium by 1,25-dihydroxy vitamin D3 - clinical implications for cardiovascular diseases

Background

Clinical studies indicate that vitamin D₃ improves circulation and may have beneficial effects in hypertension. This study uses nanomedical systems to investigate the role of 1,25-dihydroxy vitamin D₃ in the preservation/restoration of endothelial function in an angiotensin II (Ang II) cellular model of hypertension.

Methods

1,25-dihydroxy vitamin D₃-stimulated nitric oxide (NO) and peroxynitrite (ONOO⁻) concentrations were measured in situ with nanosensors (200–300 mm diameter with a detection limit of 1 nM) in human umbilical vein endothelial cells of African American (AA) and Caucasian American (CA) donors exposed to Ang II. The balance/imbalance between NO and ONOO⁻ concentrations ([NO]/[ONOO⁻]) was simultaneously monitored and used as an indicator of endothelial nitric oxide synthase (eNOS) uncoupling and endothelial dysfunction.

Results

[NO]/[ONOO⁻] imbalance in Ang II-stimulated dysfunctional endothelium was 0.20±0.16 for CAs and 0.11±0.09 for AAs. Uncoupled eNOS and overexpression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase contributed to high production of ONOO⁻. Vitamin D₃ treatment reversed [NO]/[ONOO⁻] to 3.0±0.1 in CAs and 2.1±0.1 in AAs – exceeding that observed in normal endothelium. Vitamin D₃ restored uncoupled eNOS and endothelial function by increasing cytoprotective NO and decreasing the cytotoxic ONOO⁻. The beneficial effect of vitamin D₃ is associated with a favorable rate of NO and ONOO⁻ release, restoration of the [NO]/[ONOO⁻] and the overall decrease in the overexpression of eNOS, inducible nitric oxide synthase and NADPH oxidase. This effect of vitamin D₃ may prove to be beneficial in the treatment of hypertension and other cardiovascular diseases, including heart failure, myocardial infarction, vasculopathy, stroke and diabetes.

Role of thromboxane A2 signaling in endothelium-dependent contractions of arteries

Thromboxane A₂ (TxA₂) plays a very important role in various cardiovascular diseases through its action on platelet aggregation, vasoconstriction, and proliferation. The present article focuses on the role of TxA₂ signaling in endothelium-dependent contractions of arteries. Arachidonic acid (AA) is metabolized by cyclooxygenase (COX) to form the unstable prostaglandin H₂ which is further converted into TxA₂. After being produced by thromboxane synthase (TxAS), TxA₂ ultimately stimulates TxA₂/prostanoid (TP) receptor to induce vasoconstriction. The calcium ionophore A23187, the prostanoid precursor AA, or the muscarinic receptor agonist acetylcholine (ACh) can evoke endothelium-dependent contractions associated with TxA₂. The endothelium-dependent contractions shown in hypertension, diabetes, atherogenesis, and other cardiovascular diseases have been significantly reduced by antagonism of COX, TxAS, or TP receptor. So inhibition of the bioavailability and/or effect of TxA₂ may be promising therapeutic targets to prevent these diseases. Especially some bioactive compounds isolated from medicinal plants will provide new pharmacological approaches to promote vascular health.

Vitamin D supplementation lowers thrombospondin-1 levels and blood pressure in healthy adults

INTRODUCTION

Vitamin D insufficiency, defined as 25-hydroxyvitamin D (25(OH)D) levels < 75nmol/L is associated with cardio-metabolic dysfunction. Vitamin D insufficiency is associated with inflammation and fibrosis, but it remains uncertain whether these anomalies are readily reversible. Therefore, we aimed to determine the effects of vitamin D supplementation on markers of: 1) nitric oxide (NO) signaling, 2) inflammation, and 3) fibrosis, in healthy volunteers with mild hypovitaminosis.

METHODS

Healthy volunteers (n = 35) (mean age: 45 ± 11 years) with 25(OH)D levels <75nmol/L, received vitamin D supplementation (Ostelin ® capsules 2000IU) for 12 weeks. Resting systolic and diastolic blood pressures (BP) were assessed. Routine biochemistry was examined. Plasma concentrations of asymmetric dimethylarginine (ADMA), thrombospondin-1 (TSP-1), plasminogen activator inhibitor-1 (PAI-1), hs-CRP, activin-A, and follistatin-like 3 (FSTL3) were quantitated.

RESULTS

Vitamin D administration for 12 weeks significantly increased 25-(OH)D levels (48.8 ± 16 nmol/L to 100.8 ± 23.7 nmol/L, p<0.001). There was significant lowering of systolic and diastolic BP, while there was no significant change in lipid profiles, or fasting insulin. Plasma concentrations of ADMA, hs-CRP, PAI-1, activin A, and FSTL-3 did not change with vitamin D supplementation. However, there was a marked reduction of TSP-1 (522.7 ± 379.8 ng/mL vs 206.7 ± 204.5 ng/mL, p<0.001).

CONCLUSIONS

Vitamin D supplementation in vitamin D insufficient, but otherwise healthy individuals markedly decreased TSP-1 levels and blood pressure. Since TSP-1 suppresses signaling of NO, it is possible that the fall in BP is engendered by restoration of NO effect.

Vitamin D and hypertension: Prospective study and meta-analysis

OBJECTIVES

The study sought to determine the link between vitamin D concentrations and incident hypertension in prospective study and meta-analysis.

METHODS

The study was embedded in the Kailuan Study, a population-based cohort of adults that contains underground miners. In 2012, we studied 2,456 men and women free of prevalent hypertension, age 21 to 67 at baseline. Serum 25-hydroxyvitamin D was measured from previously frozen baseline samples using ELISA (Enzyme-Linked ImmunoadSorbent Assay). We use the logistic regression analysis to estimate the odd radio (ORs) 95% confidence intervals (CIs) for 25-hydroxyvitamin D [25(OH)D] concentrations with incident hypertension. To help place our new data in context, we conducted a systemic review and meta-analysis of previous prospective reports of vitamin D and hypertension.

RESULTS

During a median follow-up of 2 years, 42.6% of the cohort (n = 1047) developed hypertension. Compared with the 25-hydroxyvitamin D >30ng/ml, 25-hydroxyvitamin D <20 ng/ml was associated with a greater hypertension risk (OR: 1.225 [95% CI: 1.010 to 1.485] p = 0.04), although the association was attenuated and not statistically significant after adjusting for potential confounders (OR: 1.092 [95% CI: 0.866 to 1.377] p = 0.456). This meta-analysis included seven prospective studies for 53,375 participants using adjusted HR founded a significant association between vitamin D deficiencies and incident hypertension (HRs = 1.235 (95% CI: 1.083 to 1.409, p = 0.002)).

CONCLUSION

Lower serum 25-hydroxyvitamin D concentrations were not associated with a greater risk of incident hypertension. More research is needed to further determine the role of 25-hydroxyvitamin D in hypertension prevention and therapy.

The effect of vitamin D supplementation on hypertension in non-CKD populations: A systemic review and meta-analysis

OBJECTIVES

To investigate the vitamin D supplementation on blood pressure control by a systemic review and meta-analysis.

METHODS

Randomized controlled clinical trials were analyzed, which date from eight studies in databases including MEDLINE, EMBASE, Clinical trials, China Integrated Knowledge Resources Database and the Cochrane library.

RESULTS

Total 917 patients from eight randomized controlled trials (RCTs), treatment with vitamin D for more than 3months were analyzed. Meta-analysis showed that vitamin D supplementation slightly reduced the systolic blood pressure (SBP) by 1.964mmHg (95% CI, 0.362-3.566; P=0.016), but not lowered diastolic blood pressure (SMD: -0.087, 95% CI, -0.208-0.033; P=0.155). Subgroup analysis also showed that sBP lowering by vitamin D supplementation was not dose-dependent. Comparison to placebo, there is also no statistical difference in SBP lowering by vitamin D supplementation.

CONCLUSIONS

This meta-analysis indicated that vitamin D is not an antihypertensive agent although it has a moderate SBP lowering effect. More RCTs are required to observe the role of vitamin D plus other antihypertensive drugs in blood pressure control, and define the optimum dose, dosing interval, and type of vitamin D to administer.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Vitamin D and its effects on cardiovascular diseases: a comprehensive review

Vitamin D is a molecule that is actively involved in multiple metabolic pathways. It is mostly known for its implications related to calcium metabolism. It has also been determined that it actively participates in the cardiovascular system, influencing blood pressure, coronary artery disease and other vascular diseases, such as heart failure and atrial fibrillation. Furthermore, it has been established that this vitamin is extensively involved in the regulation of both the renin angiotensin aldosterone system and the immune system. In this review, we present the different vitamin D metabolic pathways associated with the cardiovascular pathophysiology, and we include studies in animal and human models, as well as some of the controversies found in the literature. This review also incorporates an overview of the implications in the molecular biology and public health fields.

Hypovitaminosis D is associated with erectile dysfunction in type 2 diabetes

Diabetes is an established risk factor for erectile dysfunction (ED). The pathophysiology of ED in diabetic men is multifactorial, but it mainly involves a vascular disorder related to a reduction of endothelial function. Recently, several studies have correlated ED risk factors with vitamin D deficiency. In this study, we evaluate the relationship between 25-hydroxyvitamin D [25(OH)D] levels, erectile dysfunction, and vascular disease, in type 2 diabetes mellitus men (T2DM). In this observational study, 92 T2DM males (58.83 ± 9.73 years) underwent medical history collection, International Index of Erectile Function (IIEF-5) questionnaire, that allows the identification and grading of DE, physical examination, biochemical/hormonal blood tests, and penile echo-color Doppler ultrasonography. T2DM patients with lower 25(OH)D levels (<25 nmol/l) showed higher penile IMT (p < 0.05), waist circonference (p < 0.05), glucose concentrations (p < 0.05), and lower IIEF-5 score (p < 0.005), testosterone concentrations (p < 0.05), and cavernous peak systolic velocity (PSV) (p < 0.05), compared to patients with 25(OH)D >50 nmol/l. 25(OH)D levels were directly correlated with IIEF-5 (R = 0.39; p = 0.0001), testosterone (R = 0.24; p = 0.02), and PSV (R = 0.24; p = 0.04) and inversely with waist (R = -0.33; p = 0.002), HbA1c (R = -0.22; p = 0.03), triglyceride (R = -0.21; p = 0.06), and penile IMT (R = -0.30; p = 0.009). At multivariate analysis, 25(OH)D deficiency remained an independent predictor of DE. We demonstrate a significant association between 25(OH)D deficiency and erectile dysfunction in T2DM men. This association may be due to the influence of 25(OH)D deficiency on cardiovascular risk factor (glycaemia, HDL cholesterol, and triglycerides), testosterone plasma levels and endothelial dysfunction.

1,25(OH)2D3 Induces Placental Vascular Smooth Muscle Cell Relaxation by Phosphorylation of Myosin Phosphatase Target Subunit 1Ser507: Potential Beneficial Effects of Vitamin D on Placental Vasculature in Humans

Placental vascular dysfunction has been linked to insufficiency/deficiency of maternal vitamin D levels during pregnancy. In contrast, sufficient maternal vitamin D levels have shown beneficial effects on pregnancy outcomes. To study the role of vitamin D in pregnancy, we tested our hypothesis that vitamin D exerts beneficial effects on placental vasculature. We examined expression of CYP2R1, CYP27B1, vitamin D receptor (VDR), and CYP24A1 in placental vascular smooth muscle cells (VSMCs) in response to 1,25(OH)₂D₃. We found that VDR expression was inducible, CYP27B1 expression was dose-dependently down-regulated, and CYP24A1 expression was dose-dependently up-regulated in cells treated with 1,25(OH)₂D₃. These data suggest a feedback autoregulatory system of vitamin D existing in placental VSMCs. Using a VSMC/collagen-gel contraction assay, we evaluated the effect of 1,25(OH)₂D₃ on placental VSMC contractility. We found that, similar to losartan, 1,25(OH)₂D₃ could diminish angiotensin II-induced cell contractility. The mechanism of 1,25(OH)₂D₃-mediated VSMC relaxation was further explored by examination of Rho-associated protein kinase 1 (ROCK1)/phosphorylation of myosin phosphatase target subunit 1 (MYPT1) pathway molecules. Our results showed that p-MYPT1^Thr853 and p-MYPT1^Thr696 were undetectable. However, p-MYPT1^Ser507, but not p-MYPT1^Ser668, was significantly up-regulated in cells treated with losartan plus angiotensin II. Similar effects were also seen in cells treated with 1,25(OH)₂D₃ plus angiotensin II or 1,25(OH)₂D₃ plus losartan plus angiotensin II. Because MYPT1 serine phosphorylation could activate myosin light chain phosphatase (MLCP), and MLCP activation is an important regulatory machinery of smooth muscle cell relaxation, up-regulation of MYPT1^Ser507 phosphorylation could be a mechanism of vitamin D and/or losartan mediated placental VSMC relaxation.

Vitamin D versus placebo in improvement of endothelial dysfunction: a meta-analysis of randomized clinical trials

AIMS

The possible effect of vitamin D administration in humans on endothelial dysfunction (ED) still remains undetermined. The current meta-analysis was performed to evaluate if vitamin D could improve ED.

METHODS

Randomized, double-blind, and placebo-controlled clinical trials were identified by systematic search of the PubMed, the Cochrane Library, the Web of Science and the Scopus data bases, as well as different reviews and clinical trials articles. A random effects model was used to calculate the pooled overall effect on flow-mediated dilation (FMD) linked to the vitamin D administration. Meta-regression and subgroup analyses were performed to evaluate the impact of study characteristics on the effect of vitamin D administration on FMD.

RESULTS

A total of eight studies with nine relevant study arms were identified. The obtained results of pooled analysis showed that vitamin D administration did not improve FMD (eight studies, 529 subjects; weighted mean difference (WMD): 0.96%, 95% CI: -1.24% to 2.06%; P = 0.09). This was probably due to significant heterogeneity in between included trials (I(2) = 84%, P < 0.00001). On the other hand, subgroup analysis demonstrated that vitamin D improved FMD in trials that lasted <16 weeks; if systolic blood pressure (SBP) was higher than 140 mmHg and in trials where diastolic blood pressure (DBP) was <80 mmHg.

CONCLUSION

Although the current evidence clearly demonstrates that in certain conditions vitamin D can improve ED, a larger number of clinical trials are needed to confirm this assumption to confirm or reject the final statement on this topic.

Effect of cholecalciferol on local arterial stiffness and endothelial dysfunction in children with chronic kidney disease

BACKGROUND

As cardiovascular factors are the leading cause of mortality in chronic kidney disease (CKD) and as vitamin D deficiency is prevalent in this population, we aimed to examine the effect of oral cholecalciferol on cardiac parameters and biomarkers for endothelial cell activation in children with CKD.

METHODS

Forty-one children with CKD and 24 healthy subjects free of any underlying cardiac or renal disease with low 25-hydroxyvitamin D3 (25OHD) levels were evaluated using echocardiography basally and following Stoss vitamin D supplementation. The local vascular stiffness and endothelial dysfunction markers were compared among the groups.

RESULTS

Initial flow-mediated dilatation (FMD) measurements were lower and local arterial stiffness was significantly higher in patients. After vitamin D supplementation, these improved significantly in patients, while no significant change was observed for the healthy group. Homocysteine showed inverse correlation with baseline vitamin D level in CKD children and von Willebrand factor emerged as an independent risk factor for FMD impairment.

CONCLUSIONS

Our interventional study revealed the favorable effects of high-dose cholecalciferol on cardiovascular and endothelial parameters, implying the importance of vitamin D supplementation in children with CKD.

Vitamin D and Anaesthesia

Vitamin D is a vitamin not only associated with calcium-phosphorus metabolism but also affects many organ systems. Because of its effect on the immune system in recent years, it has attracted much attention. Vitamin D deficiency is a clinical condition that can be widely observed in the society. Thus, patients with vitamin D deficiency are often seen in anaesthesia practice. In the absence of vitamin D, prolongation of intensive care unit stay, increase in mortality and morbidity and also association of chronic diseases further increase the importance of vitamin D deficiency. The results obtained from studies have led to the question of whether poor surgical outcome is associated with vitamin D deficiency. We assessed the vitamin D deficiency and its negative consequences for the anaesthesiologist.

Vitamin D Levels Decline with Rising Number of Cardiometabolic Risk Factors in Healthy Adults: Association with Adipokines, Inflammation, Oxidative Stress and Advanced Glycation Markers

INTRODUCTION

Hypovitaminosis D associates with obesity, insulin resistance, hypertension, and dyslipoproteinemia. We asked whether the presence of multiple cardiometabolic risk factors, and which particular combination, exerts additive negative effects on 25(OH)D3 levels; and whether 25(OH)D3 levels associate with markers of inflammation and oxidative stress.

SUBJECTS AND METHODS

In non-diabetic medication-free adults central obesity (waist-to-height ratio > 0.5); elevated blood pressure (systolic BP≥130 mm Hg and/or diastolic BP ≥85 mm Hg); increased atherogenic risk (log(TAG/HDL) ≥ 0.11); and insulin resistance (QUICKI < 0.322) were considered as cardiometabolic risk factors. 25(OH)D3 status was classified as deficiency (25(OH)D3 ≤20 ng/ml); insufficiency (levels between 20-to-30 ng/ml), or as satisfactory (>30 ng/ml). Plasma adipokines, inflammatory and oxidative stress markers, advanced glycation end-products, and their soluble receptor were determined.

RESULTS

162 subjects were cardiometabolic risk factors-free, 162 presented increased (i.e. 1 or 2), and 87 high number (i.e. 3 or 4) of cardiometabolic risk factors. Mean 25(OH)D3 decreased with rising number of manifested risk factors (36 ± 14 ng/ml, 33 ± 14 ng/ml, and 31 ± 15 ng/ml, respectively; pANOVA: 0.010), while prevalence of hypovitaminosis D did not differ significantly. Elevated blood pressure and insulin resistance appeared as significant determinants of hypovitaminosis D. Subjects presenting these risk factors concurrently displayed the lowest 25(OH)D3 levels (29 ± 15 ng/ml). Plasma adipokines, inflammatory and oxidative stress markers, advanced glycation end-products, and their soluble receptor generally differed significantly between the groups, but only advanced oxidation protein products and advanced glycation end-products associated fluorescence of plasma showed significant independent association with 25(OH)D3 levels.

CONCLUSION

In apparently healthy adults increasing number of cardiometabolic risk factors associates with poorer 25(OH)D3 status, while the association between 25(OH)D3 status and inflammatory or oxidative stress markers remains equivocal.

Vitamin D for the prevention of cardiovascular disease: Are we ready for that?

A general concept of clinical benefit of vitamin D supplementation has emerged from the evidence in prevention of osteoporosis. From the cardiovascular point of view, clinical benefit of such supplementation remains less clear. Studies in vitro and in animal models demonstrated the expression of vitamin D receptors in endothelial cells, vascular smooth muscle and cardiomyocytes. Vitamin D has been directly implicated in endothelium-mediated vasodilation, anti-coagulant activity and inhibition of the inflammatory response. Indirectly, it may favor the reduction of blood pressure, myocardial hypertrophy and ventricular arrhythmias. In contrast to these mechanistic findings, cross-sectional, longitudinal and small clinical trials have not been consistent in demonstrating association between cardiovascular events and vitamin D. Besides, methodological issues in the tests for serum levels of vitamin D may also contribute to this puzzle. Hence, in the current state of knowledge, it may be too early to consider or to rule out vitamin D as a tool to either estimate or mitigate residual cardiovascular risk. In this review, we discuss recent advances and potential limitations in mechanistic and clinical evidences that are outlining the framework of interaction between vitamin D and cardiovascular risk.

Reduced activity of SKC a and Na-K ATPase underlies the accelerated impairment of EDH-type relaxations in mesenteric arteries of aging spontaneously hypertensive rats

Aging is accompanied by endothelial dysfunction due to reduced bioavailability of nitric oxide (NO) and/or reduced endothelium-dependent hyperpolarizations (EDH). This study examines the hypothesis that hypertension aggravates the impairment of EDH-type relaxation due to aging. EDH-type relaxations were studied in superior mesenteric arteries isolated from Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats of 12, 36, 60, and 72 weeks of age. EDH-type relaxations in WKY were reduced with aging, and this was associated with an impairment of the function of small-conductance calcium-activated potassium channels (SK_Ca) and sodium-potassium ATPase (Na-K ATPase). EDH-type relaxation in SHR was smaller than that in WKY arteries, and further reduction occurred with aging. Pharmacological experiments suggested a reduced involvement of SK_Ca and Na-K ATPase and activation of adenosine monophosphate-activated protein kinase and silent information regulator T1 (sirtuin-1; SIRT1) in mesenteric arteries of 12-week-old SHR. These pharmacological findings suggest that in superior mesenteric arteries of the rat, the reduction in EDH-type relaxation occurs with aging and that such a reduction is exacerbated in hypertension. The latter exacerbation appears to involve proteins associated with the process of cellular senescence and is related to impaired function of SK_Ca and Na-K ATPase, a phenomenon that is also observed in mesenteric arteries of older normotensive rats.

Links between Vitamin D Deficiency and Cardiovascular Diseases

The aim of the present paper was to review the most important mechanisms explaining the possible association of vitamin D deficiency and cardiovascular diseases, focusing on recent experimental and clinical data. Low vitamin D levels favor atherosclerosis enabling vascular inflammation, endothelial dysfunction, formation of foam cells, and proliferation of smooth muscle cells. The antihypertensive properties of vitamin D include suppression of the renin-angiotensin-aldosterone system, renoprotective effects, direct effects on endothelial cells and calcium metabolism, inhibition of growth of vascular smooth muscle cells, prevention of secondary hyperparathyroidism, and beneficial effects on cardiovascular risk factors. Vitamin D is also involved in glycemic control, lipid metabolism, insulin secretion, and sensitivity, explaining the association between vitamin D deficiency and metabolic syndrome. Vitamin D deficit was associated in some studies with the number of affected coronary arteries, postinfarction complications, inflammatory cytokines and cardiac remodeling in patients with myocardial infarction, direct electromechanical effects and inflammation in atrial fibrillation, and neuroprotective effects in stroke. In peripheral arterial disease, vitamin D status was related to the decline of the functional performance, severity, atherosclerosis and inflammatory markers, arterial stiffness, vascular calcifications, and arterial aging. Vitamin D supplementation should further consider additional factors, such as phosphates, parathormone, renin, and fibroblast growth factor 23 levels.