The world pandemic of vitamin D deficiency could possibly be explained by cellular inflammatory response activity induced by the renin-angiotensin system

Association between serum vitamin D level and cardiovascular disease in Chinese patients with type 2 diabetes mellitus: a cross-sectional study

The relationship between 25-hydroxyvitamin D (25(OH)D) status and cardiovascular disease (CVD) in the diabetes population still needs to be clarified. This study aimed to explore the association of 25(OH)D with CVD and cardiometabolic risk factors in Chinese population with type 2 diabetes mellitus (T2DM). This cross-sectional study was performed with 1378 hospitalized patients with T2DM. Participants were classified into three groups according to the serum 25(OH)D levels: vitamin D adequate, vitamin D insufficiency and vitamin D deficient. Multivariate logistic regression analysis, stratified analysis and interaction analysis were performed to determine the relationship between serum 25(OH)D levels and CVD outcome. After adjusting for confounders, serum 25(OH)D levels were significantly negatively associated with cardiovascular disease in type 2 diabetic patients [OR: 0.97 (0.94, 0.99), p = 0.0131]. Taking the vitamin D-sufficient group (≥ 20 ng/mL) as a reference, the vitamin D-deficiency group (< 12 ng/mL) was associated with a significantly higher risk of cardiovascular disease, with a 1.25-fold increased risk after adjusting for all potential confounders [OR: 2.25 (1.33, 3.79), p = 0.0023]. Stratification analysis showed that the association between vitamin D deficiency and increased risk of cardiovascular disease was particularly significant in women [OR: 4.32 (1.54, 12.12), p = 0.0055], older adults [OR: 4.14 (1.10, 15.56), p = 0.0355], normal-weight [OR: 4.09 (1.51, 11.10), p = 0.0056] and obese subjects [OR: 3.66 (1.03, 13.05), p = 0.0453]. Vitamin D deficiency was significantly associated with an increased risk of overweight/obesity [OR: 1.57 (1.10, 2.24), p = 0.0134], hypertension [OR: 1.81 (1.30, 2.51), p = 0.0004], hypertriglyceridemia [OR: 1.56 (1.12, 2.16), p = 0.0078] and reduced HDL-C [OR: 1.67 (1.19, 2.35), p = 0.0033]. Serum 25(OH)D levels were significantly negatively associated with CVD in T2DM patients and vitamin D deficiency was significantly associated with an increased risk of overweight/obesity, hypertension and dyslipidemia.

Calcitriol Concentration in the Early Phase of Myocardial Infarction and Its Relation to Left Ventricular Ejection Fraction

Vitamin D deficiency is one of the most common metabolic disorders in the European population. A low level of 25-OH vitamin D3 is related to an elevated risk of myocardial infarction (MI). The aim of our study was to examine the relationship between calcidiol and calcitriol serum concentration and left ventricular ejection fraction early after interventional treatment for acute coronary syndrome. A total of 80 patients diagnosed with MI, who underwent primary percutaneous coronary intervention, were included in the study. Blood samples for calcidiol, calcitriol, and vitamin D-binding protein were obtained 24 h after primary PCI and were measured using an enzyme-linked immunosorbent assay. Only 9% of patients had a proper level of 25-OHD3 in the serum (30-80 ng/mL). A total of 16% of patients revealed a suboptimal concentration of 25-OHD3 (20-30 ng/mL), and in 75% of patients, the concentration of 25-OHD3 was lower than 20 ng/mL. Moreover, patients with left ventricle ejection fraction of <40% had significantly lower concentrations of calcidiol and calcitriol. A low calcitriol serum concentration affects post-MI left ventricle ejection fraction early after myocardial infarction onset. It seems that 1.25(OH)D3 may contribute to acute myocardial infarction; however, there are insufficient clinical trials related to this topic, and the available evidence is mainly from in vitro studies. We hope these preliminary reports will provide a better understanding of post-MI.

Lower levels of vitamin D are associated with an increase in carotid intima-media thickness in children and adolescents with obesity

Introduction

Background: the relationship between vitamin D deficiency and carotid intima-media thickness (CIMT) in children and adolescents with obesity is unknown. The aim of this study was to investigate the correlation between vitamin D levels and CIMT in children and adolescents with obesity. Methods: a total of 440 children and adolescents aged 6-16 with obesity were included in the study. Anthropometric measurements, blood pressure measurements, blood lipids, blood glucose, and vitamin D levels were measured. Bilateral carotid ultrasound was performed to assess CIMT. The relationships between vitamin D levels and CIMT were assessed using multivariate linear regression with Generalized Linear Models and restricted cubic splines. Binary logistic regression analyses were conducted to explore the association between vitamin D status and the risk of abnormal CIMT. Results: vitamin D levels were inversely correlated with CIMT in subjects with serum 25-hydroxyvitamin D [25(OH)D] levels less than or equal to 50 nmol/L (ß = -0.147, 95 % CI [-0.263, -0.030], p = 0.013), but this correlation was not significant in subjects with serum 25(OH)D levels above 50 nmol/L. After correcting for various confounders, the risk of abnormal CIMT was significantly higher in the vitamin D deficiency group (OR = 2.080, 95 % CI [1.112, 3.891], p = 0.022). Conclusions: vitamin D deficiency is an independent risk factor for abnormal CIMT, and vitamin D deficiency may play a promoting role in the atherosclerotic process in children and adolescents with obesity.

The potential protective role of vitamin D and calcium supplements in reducing cardiovascular disease risk among elderly patients with osteopenia

BACKGROUND

Cardiovascular disease and low bone mineral density are major health problems in the elderly. These two conditions are considered independent of each other and age-related diseases. The aim of this study is to investigate the association between low bone mineral density (BMD) and cardiovascular disease (CVD) incidents, and the effect of vitamin D and calcium supplement on the incidence of CVD in patients with low BMD.

METHODS

A total of 1047 patients (597 females/450 males) with the age of 65 years and more were diagnosed with osteopenia for 13 years or more. The study also included 220 patients (107 females/113 males) with osteopenia who already took calcium and vitamin D continually since their diagnosis. BMD was measured by dual-energy X-ray absorptiometry. The incidence of any cardiovascular diseases in the study patients and the presence of corresponding risk factors were collected and analyzed.

RESULTS

In both elderly Arab females and males, there was an association between total hip and femoral neck BMD and the possibility to have CVD. On the other hand, the results showed that patients who use calcium and vitamin D supplements showed a significant reduction in the incidence of CVD comparing to the non-treated patients.

CONCLUSION

Low total hip and femoral neck BMD were associated with a higher chance to have CVD incidents in both elderly Arab males and females; moreover, calcium and vitamin D supplements have a possible protective role in reducing cardiovascular disease in elderly patients with osteopenia.

Vitamin D3 supplementation in COVID-19 patients with cardiovascular disease and gut dysbiosis

BACKGROUND

The COVID-19 pandemic has highlighted the vulnerability of particular patient groups to SARS-CoV-2 infection, including those with cardiovascular diseases, hypertension, and intestinal dysbiosis. COVID-19 affects the gut, suggesting diet and vitamin D3 supplementation may affect disease progression.

AIMS

To evaluate levels of Ang II and Ang-(1-7), cytokine profile, and gut microbiota status in patients hospitalized for mild COVID-19 with a history of cardiovascular disease and treated with daily doses of vitamin D3.

METHODS

We recruited 50 adult patients. We screened 50 adult patients and accessed pathophysiology study 22, randomized to daily oral doses of 10,000IU vitamin D3 (n=11) or placebo (n=11). Plasma levels of Ang II and Ang-(1-7) were determined by radioimmunoassay, TMA and TMAO were measured by liquid chromatography and interleukins (ILs) 6, 8, 10 and TNF-α by ELISA.

RESULTS

The Ang-(1-7)/Ang II ratio, as an indirect measure of ACE2 enzymatic activity, increased in the vitamin D3 group (24±5pg/mL vs. 4.66±2pg/mL, p<0.01). Also, in the vitamin D3-treated, there was a significant decline in inflammatory ILs and an increase in protective markers, such as a substantial reduction in TMAO (5±2μmoles/dL vs. 60±10μmoles/dL, p<0.01). In addition, treated patients experienced less severity of infection, required less intensive care, had fewer days of hospitalization, and a reduced mortality rate. Additionally, improvements in markers of cardiovascular function were seen in the vitamin D3 group, including a tendency for reductions in blood pressure in hypertensive patients.

CONCLUSIONS

Vitamin D3 supplementation in patients with COVID-19 and specific conditions is associated with a more favourable prognosis, suggesting therapeutic potential in patients with comorbidities such as cardiovascular disease and gut dysbiosis.

Differential effects of cholecalciferol and calcitriol on muscle proteolysis and oxidative stress in angiotensin II-induced C2C12 myotube atrophy

Renin-angiotensin system activation contributes to skeletal muscle atrophy in aging individuals with chronic diseases. We aimed to explore the effects of cholecalciferol (VD3) and calcitriol (1,25VD3) on signaling of muscle proteolysis and oxidative stress in myotubes challenged with angiotensin II (AII). The mouse C2C12 myotubes were assigned to vehicle, AII, AII + VD3, AII + 1,25VD3, and AII + losartan groups. The expression levels of muscle-specific E3 ubiquitin ligase proteins, autophagy-related proteins, and oxidative stress markers were investigated. We demonstrated the diverse effects of VD3 and 1,25VD3 on AII-induced myotube atrophy. The myotube diameter was preserved by treatment with 100 nM VD3 and losartan, while 1 and 10 nM 1,25VD3 increased levels of FoxO3a, MuRF1, and atrogin-1 protein expression in myotubes exposed to AII. Treatment with AII + 10 nM 1,25VD3 resulted in the upregulation of LC3B-II, LC3B-II/LC3B-I, and mature cathepsin L, which are autophagic marker proteins. The p62/SQSTM1 protein was downregulated and vitamin D receptor was upregulated after treatment with AII + 10 nM 1,25VD3. A cellular redox imbalance was observed as AII + 10 nM 1,25VD3-induced reactive oxygen species and NADPH oxidase-2 overproduction, and these changes were associated with an inadequate response of antioxidant superoxide dismutase-1 and catalase proteins. Collectively, these findings provide a translational perspective on the role of vitamin D3 in alleviating muscle atrophy related to high levels of AII.

Associations between Aging and Vitamin D Status with Whole-Body Nitric Oxide Production and Markers of Endothelial Function

BACKGROUND

Aging and vitamin D deficiency have been associated with reduced nitric oxide (NO) synthesis and impaired endothelial function (EF) but the evidence in humans remains weak.

OBJECTIVES

Two independent cross-sectional studies were designed to evaluate the association between age, sex, and plasma vitamin D concentrations with physiological and biochemical biomarkers of NO synthesis and EF in young and older healthy participants (Study 1) and in overweight and obese postmenopausal females (Study 2).

METHODS

In Study 1, 40 young (20-49 y) and older (50-75 y) males and females (10 participants per age and sex group) were included. Resting blood pressure and ear-to-finger peripheral pulse wave velocity (PWV) were measured. A stable-isotopic method was used to determine whole-body NO production. Plasma 25-hydroxyvitamin D (25(OH)D), nitrate, nitrite, and asymmetric dimethylarginine (ADMA) concentrations were determined. In Study 2, 80 older overweight and obese females (age 61.2 ± 6.2 y, body mass index 29.5 ± 4.4 kg/m2) were recruited. Postocclusion reactive hyperemia (PORH) and peripheral PWV were measured. Plasma concentrations of 25(OH)D, nitrate, cyclic guanosine monophosphate, 3-nitrotyrosine (3-NT), endothelin-1, vascular endothelial growth factor, and ADMA were determined.

RESULTS

In Study 1, whole-body NO production was significantly greater in young compared with older participants (0.61 ± 0.30 μmol·h-1·kg-1 compared with 0.39 ± 0.10 μmol·h-1·kg-1, P = 0.01) but there was no evidence of a sex difference (P = 0.81). Plasma 25(OH)D concentration was not associated with PWV (r = 0.18, P = 0.28) or whole-body NO production (r = -0.20, P = 0.22). Plasma ADMA concentration was associated positively with age (r = 0.35, P = 0.03) and negatively with whole-body NO production (r = -0.33, P = 0.04). In Study 2, age was associated with lower PORH (r = -0.28, P = 0.02) and greater ADMA concentrations (r = 0.22, P = 0.04). Plasma 25(OH)D concentration was inversely associated with 3-NT concentrations (r = -0.31, P = 0.004).

CONCLUSIONS

Older age was associated with lower whole-body NO production. Plasma vitamin D concentrations were not associated with NO production or markers of EF but showed a weak, significant correlation with oxidative stress in postmenopausal overweight females.

Dietary inflammatory index is associated with Vitamin D in CKD patients

OBJECTIVES

Multiple observational studies have shown that low serum level of 25-hydroxyvitamin D (25(OH)D) in patients with chronic kidney disease (CKD) have been associated with a faster progression of kidney disease and a higher risk of all-cause mortality. We aim to assess the association between dietary inflammatory index (DII) with Vitamin D in adults with CKD.

METHOD

The National Health and Nutrition Examination Survey appropriated participants from 2009 to 2018 were enrolled. The patients who were under the age of 18, pregnant, and having incomplete data were excluded. DII score were calculated based on a single 24-h dietary recall interview for each participant. Mutivariable regression analysis and subgroup analysis were utilized to determine the independent associations between vitamin D with DII in CKD patients.

RESULTS

In total, 4283 individuals were finally included. The results showed a negative association between DII scores and 25(OH)D with statistical significance (β =  - 1.83, 95% CI  - 2.31,  - 1.34, P < 0.001). In subgroup analysis stratified by gender, low eGFR, age and diabetes, the negative association between DII scores and 25(OH)D was still significant (all P for trend < 0.05). The results from interacion test indicated that the magnitude of the association was the same for the population with and without low eGFR (P for interacion = 0.464).

CONCLUSION

Higher consumption of pro-inflammatory diet correlates negatively with the 25(OH)D level in CKD patients with and without low eGFR. Anti-inflammatory diet management may reduce the reduction of vitamin D in CKD patients.

Novel Insight Into the Relationship of Vitamin D Hydroxylase and Vitamin D With Obesity in Patients With Type 2 Diabetes Mellitus

BACKGROUND

In patients with type 2 diabetes mellitus (T2DM) and obesity, there is often a vitamin D deficiency, which is crucial for many physiological processes. The enzyme 25-D hydroxylase activates vitamin D, and its status has been linked to glucose and lipid metabolism in these patients. This study investigates the correlation between the levels of 25-D hydroxylase and 25-hydroxyvitamin D, and their impact on glucose and lipid metabolism in Saudi patients with T2DM and obesity.

METHODS

This study involved 150 Saudi participants (ages 35-70) of both genders from King Faisal Medical Complex in Taif. The participants were divided into control, type 2 diabetic, and obese diabetic patient groups, with 50 subjects in each group. Serum levels of 25(OH) vitamin D and 25-D hydroxylase were measured using ELISA. In contrast, an automatic analyzer for chemistry tests was used to measure fasting blood glucose (FBG), aspartate transaminase (AST), alanine transaminase (ALT), and lipid profile levels. Hemoglobin A1c (HbA1c)% was analyzed using the automatic glycosylated hemoglobin analyzer. In addition, the body mass index (BMI) value was calculated using the equation (BMI = weight in kilograms/height in meters squared).

RESULTS

In obese with T2DM and T2DM patient groups, there were significant increases (p < 0.0001) in BMI, FBG, HbA1c%, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), AST, and ALT levels and significant decreases (p < 0.0001) in 25(OH) vitamin D, 25-D hydroxylase, and high-density lipoprotein cholesterol (HDL-C) levels compared to the control group. There were significant positive correlations between vitamin D with 25-D hydroxylase and HDL-C and negative correlations with HbA1c%, FBG, TC, TG, LDL-C, ALT, AST, and BMI in the studied patient groups.

CONCLUSIONS

This study shows that lower levels of the enzyme 25-D hydroxylase are linked to reduced vitamin D levels in people with T2DM and obese diabetic patients. Additionally, there was a notable correlation between vitamin D levels and BMI, lipid profile, FBG, HbA1c%, AST, and ALT levels.

Effect of vitamin D on cardiac hypertrophy in D-galactose-induced aging model through cardiac mitophagy

BACKGROUND

Cardiac apoptosis plays a key role in increased morbidity associated with aging-induced-cardiac disorder. Mitochondria play an important role in cardiac apoptosis, and dynamin-related protein 1 (Drp1), as a main mediator of mitochondrial fission, can trigger the mitophagy process to sustain the mitochondrial quality. The present study was done to determine the effect of vitamin D (VitD) treatment on cardiac hypertrophy through mitophagy regulation in aged animals induced by D-galactose (D-GAL).

METHODS AND RESULTS

Male Wistar rats were randomly divided into four groups: control, D-GAL (aging group), D-GAL co-injected with VitD (D-GAL ± VitD), and D-GAL plus ethanol (D-GAL ± Ethanol). Aging was induced by an intraperitoneal (i.p.) administration of D-GAL at 150 mg/kg daily for eight weeks and also VitD (400 IU/kg) or ethanol was injected (i.p.) into aging rats. Then, the levels of cardiac mitophagy and cardiac apoptosis were determined by measuring the expression of tensin homologue (PTEN)-induced putative kinase 1 (PINK1), Drp1, Bcl2-Associated X (Bax), and B-cell lymphoma 2 (Bcl2) genes. Aging in rats was associated with a reduction in mitophagy and also an increase in apoptosis of the heart through down-regulation of Drp1, PINK1, and Bcl2 genes and also up-regulation of Bax. However, VitD improved cardiac hypertrophy through cardiac mitophagy in D-GAL-induced aging rats.

CONCLUSION

VitD can inhibit cardiac hypertrophy by an increase in mitophagy and a decrease in apoptosis in the aging heart. The illustration of the suggested mechanism underlying of Vitamin D in cardiac hypertrophy induced by aging.

Vitamin D on Cardiac Function in Heart Failure: A Systematic Review and Meta-Analysis of 10 RCTs

Background

Systematic evaluation of the effects of vitamin D supplementation in heart failure (HF) patients.

Methods

Searches were conducted on National Library of Medicine, Web of Science, Cochrane Library, Google Scholar, China National Knowledge Infrastructure, and WANFANG databases. We analyzed data by using Review Manager 5.4 software. All are from the earliest records to March 2023. Outcome indicators analyzed the left ventricular ejection fraction (LVEF), the left ventricular end-diastolic internal diameter (LVEDD), the B-type brain natriuretic peptide (BNP) level and the 25-hydroxy vitamin D (25(OH)D) level.

Results

Ten studies with 1099 patients were included. LVEF (mean difference (MD) = 0.74, 95% CI: -0.29 to 1.76, p = 0.41), LVEDD (MD = -0.59, 95% CI: -1.83 to 0.66, p = 0.25), BNP (MD = -0.08, 95% CI: -0.24 to 0.08, p = 0.34), 25(OH)D (MD = 0.41, 95% CI: -0.28 to 1.11, p = 0.25) are not statistically significant. And there is no heterogeneity in the results of LVEF, LVEDD and BNP indicators.

Conclusions

Vitamin D supplementation may not be helpful in the clinical management of patients with HF.

Vitamin D Improves Cognitive Impairment and Alleviates Ferroptosis via the Nrf2 Signaling Pathway in Aging Mice

Ferroptosis is an iron-dependent mode of cell death associated with the occurrence and development of age-related neurodegenerative diseases. Currently, there are no effective drugs available to prevent or treat these aging-related neurodegenerative diseases. Vitamin D (VD) is an antioxidant and immunomodulator, but its relationship with ferroptosis in aging-related neurodegenerative diseases has not been extensively studied. In this study, we aimed to investigate the role of VD in learning and memory in aging mice. To examine whether VD protects aging hippocampal neurons, we used physiologically active 1,25(OH)2D3. We established aging models in vivo (C57BL/6 mice) and in vitro (HT22 cells) using D-galactose (D-gal). The results demonstrated that VD could improve learning and memory in mice aged via the use of D-gal, and it reduced damage to hippocampal neurons. VD could regulate ferroptosis-related proteins (increasing GPX4 expression and decreasing ACSL4 and ALOX15 protein expression levels), increasing GSH levels, reducing MDA and intracellular and mitochondrial ROS levels, as well as total iron and Fe2+ levels, and improving mitochondrial morphology, thereby alleviating ferroptosis in aging hippocampal neurons. Additionally, VD activated the VDR/Nrf2/HO-1 signaling pathway, thereby inhibiting ferroptosis. Notably, when the VDR was knocked down, VD lost its ability to activate Nrf2. Consequently, inhibiting Nrf2 decreased the protective effect of VD against ferroptosis in aged hippocampal neurons. In summary, VD activates the Nrf2/HO-1 signaling pathway through the VDR, effectively preventing ferroptosis induced by aging in hippocampal neurons.

Differences in Chronic Low-Grade Inflammation and Metabolic Disturbances between VDR Genotypes in an Ethnically Homogenous Postmenopausal Female Population from Poland

(1) Vitamin D deficiency and changes in the endocrine system may stimulate systemic inflammation. VDR expression and the vitamin D concentration decrease with age, which is important in postmenopausal women for whom estrogen deficiency causes rapid bone loss. This group is, moreover, particularly at risk of developing atherosclerosis and its adverse consequences, such as chronic inflammation. The aim of this study was to assess the differentiation by the VDR genotype of the risk factors for so-called chronic low-grade inflammation and metabolic disorders. (2) We studied the differences between the anthropometric, metabolic, and inflammation parameters of VDR genotypes for Apa-I, Bsm-I, Fok-I, and Taq-I in a sample of 321 women aged 50-60 from an ethnically homogeneous urban population in Poland. (3) The TT Taq-I genotype presented a significantly higher rate of insulin resistance (HOMA) and lower serum levels of adiponectin than the other two genotypes. The AA genotype of the Bsm-I polymorphism was associated with a more atherogenic serum profile and significantly higher LDL and LDL/HDL values and Castelli Index. (4) Chronic low-grade inflammation was associated with the TT Taq-I genotype and presented a higher rate of insulin resistance. The AA genotype of the Bsm-I polymorphism presented a more atherogenic serum lipid profile and, therefore, a higher risk of developing cardiovascular disease.

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.

Pathogenesis of (smoking-related) non-communicable diseases-Evidence for a common underlying pathophysiological pattern

Non-communicable diseases, like diabetes, cardiovascular diseases, cancer, stroke, chronic obstructive pulmonary disease, osteoporosis, arthritis, Alzheimer's disease and other more are a leading cause of death in almost all countries. Lifestyle factors, especially poor diet and tobacco consumption, are considered to be the most important influencing factors in the development of these diseases. The Western diet has been shown to cause a significant distortion of normal physiology, characterized by dysregulation of the sympathetic nervous system, renin-angiotensin aldosterone system, and immune system, as well as disruption of physiological insulin and oxidant/antioxidant homeostasis, all of which play critical roles in the development of these diseases. This paper addresses the question of whether the development of smoking-related non-communicable diseases follows the same pathophysiological pattern. The evidence presented shows that exposure to cigarette smoke and/or nicotine causes the same complex dysregulation of physiology as described above, it further shows that the factors involved are strongly interrelated, and that all of these factors play a key role in the development of a broad spectrum of smoking-related diseases. Since not all smokers develop one or more of these diseases, it is proposed that this disruption of normal physiological balance represents a kind of pathogenetic "basic toolkit" for the potential development of a range of non-communicable diseases, and that the decision of whether and what disease will develop in an individual is determined by other, individual factors ("determinants"), such as the genome, epigenome, exposome, microbiome, and others. The common pathophysiological pattern underlying these diseases may provide an explanation for the often poorly understood links between non-communicable diseases and disease comorbidities. The proposed pathophysiological process offers new insights into the development of non-communicable diseases and may influence the direction of future research in both prevention and therapy.

Vitamin D and heart failure: A two-sample mendelian randomization study

BACKGROUND AND AIMS

The relationship between vitamin D and heart failure (HF) has attracted significant interest, but the association between the two in previous studies remains uncertain. Therefore, we used two-sample Mendelian randomization (MR) to investigate a causal association between 25-hydroxyvitamin D (25OHD) and HF risk.

METHODS AND RESULTS

This study utilized summary statistics from the most extensive genome-wide association studies for 25OHD and HF. To make the results more reliable, we used several methods based on three assumptions for MR analysis. We also used the multivariable MR adjusting for hypertension, BMI, diabetes, chronic kidney disease to further elucidate the association between 25OHD and HF. Considering the potential pleiotropy, we performed an MR analysis with conditionally independent genetic instruments at core genes to further determine the relationship between vitamin D and heart failure. We found that per 1 SD increase in standardized log-transformed 25OHD level, the relative risk of HF decreased by 16.5% (OR: 0.835, 95% Cl: 0.743-0.938, P = 0.002), and other MR methods also showed consistent results. The multivariable MR also reported that per 1 SD increase in standardized log-transformed 25OHD level, the relative risk of HF decreased. And the scatter plots showed a trend towards an inverse MR association between 25OHD levels, instrumented by the core 25OHD genes, and HF.

CONCLUSION

In summary, we found a potential inverse association between elevated 25OHD levels and the risk of HF, which suggested that timely 25OHD supplementation or maintaining adequate 25OHD concentrations may be an essential measure for HF prevention in the general population.

The Role of CYP3A in Health and Disease

CYP3A is an enzyme subfamily in the cytochrome P450 (CYP) superfamily and includes isoforms CYP3A4, CYP3A5, CYP3A7, and CYP3A43. CYP3A enzymes are indiscriminate toward substrates and are unique in that these enzymes metabolize both endogenous compounds and diverse xenobiotics (including drugs); almost the only common characteristic of these compounds is lipophilicity and a relatively large molecular weight. CYP3A enzymes are widely expressed in human organs and tissues, and consequences of these enzymes' activities play a major role both in normal regulation of physiological levels of endogenous compounds and in various pathological conditions. This review addresses these aspects of regulation of CYP3A enzymes under physiological conditions and their involvement in the initiation and progression of diseases.

Vitamin D Ameliorates Apoptosis and Inflammation by Targeting the Mitochondrial and MEK1/2-ERK1/2 Pathways in Hyperoxia-Induced Bronchopulmonary Dysplasia

Purpose

Bronchopulmonary dysplasia (BPD) is a common and severe complication in preterm infants. Vitamin D (VitD) has been reported to protect against BPD; however, its role in the mitochondria-mediated and MEK1/2-ERK1/2 pathways has not yet been reported.

Methods

We first performed in vivo studies using neonatal C57BL/6 mice in which we induced BPD by exposing them to a hyperoxic environment (85% O₂). The mice were divided into room air (RA; 21% O₂), RA+VitD, BPD, and BPD+VitD groups. Hematoxylin and eosin and Masson’s trichrome staining were used to evaluate lung injury. Inflammation and apoptosis were measured using ELISA, RT-qPCR, and TUNEL assays. We then analyzed BEAS-2B cells divided into the same groups along with an additional BPD+VitD+inhibitor group. Mitochondrial apoptosis was evaluated by transmission electron microscopy, mitochondrial membrane potential, and Western blotting. We then used VDR-shRNA to silence the Vitamin D Receptor (VDR) in the BEAS-2B cells. The inflammation, apoptotic rate, and the phosphorylated forms of MEK1/2 and ERK1/2 in cells were detected by RT-qPCR, flow cytometry, and Western blotting.

Results

The mean linear intercept, septal thickness, and abnormal fibrosis increased, while radial alveolar count decreased in BPD lungs compared to RA lungs. VitD administration was able to ameliorate the phenotype in BPD lungs. IL-6, IFN-γ, and TNF-α expression and the apoptotic rate decreased in the BPD+VitD lung group. VitD pretreatment restored abnormal mitochondrial morphology, reduced mitochondrial membrane loss, and reduced the expression of cleaved caspase-3, Bax, and Bcl-2 in BEAS-2B cells. VitD administration also reduced IL-6, IFN-γ, and TNF-α mRNA, as well as pMEK1/2 and pERK1/2 expression and apoptosis rate in cells exposed to hyperoxia.

Conclusion

We concluded that VitD treatment ameliorated apoptosis and inflammation by targeting the mitochondrial pathway and via the MEK1/2-ERK1/2 signaling pathway in BPD, thus supporting its potential therapeutic use in this condition.

Association between metabolic body composition status and vitamin D deficiency: A cross-sectional study

This study aimed to investigate the risk of vitamin D deficiency in a relatively healthy Asian population, with (i) metabolically healthy normal weight (MHNW) (homeostasis model assessment-insulin resistance [HOMA-IR] < 2. 5 without metabolic syndrome [MS], body mass index [BMI] < 25), (ii) metabolically healthy obesity (MHO) (HOMA-IR < 2.5, without MS, BMI ≥ 25), (iii) metabolically unhealthy normal weight (MUNW) (HOMA-IR ≥ 2.5, or with MS, BMI < 25), and (iv) metabolically unhealthy obesity (MUO) (HOMA-IR ≥ 2.5, or with MS, BMI ≥ 25) stratified by age and sex. This cross-sectional study involved 6,655 participants aged ≥ 18 years who underwent health checkups between 2013 and 2016 at the Chang Gung Memorial Hospital. Cardiometabolic and inflammatory markers including anthropometric variables, glycemic indices, lipid profiles, high-sensitivity C-reactive protein (hs-CRP), and serum 25-hydroxy vitamin D levels, were retrospectively investigated. Compared to the MHNW group, the MHO group showed a higher odds ratio (OR) [1.35, 95% confidence interval (CI) 1.05-1.73] for vitamin D deficiency in men aged < 50 years. By contrast, in men aged > 50 years, the risk of vitamin D deficiency was higher in the MUO group (OR 1.44, 95% CI 1.05-1.97). Among women aged < and ≥ 50 years, the MUO group demonstrated the highest risk for vitamin D deficiency, OR 2.33 vs. 1.54, respectively. Our study revealed that in women of all ages and men aged > 50 years, MUO is associated with vitamin D deficiency and elevated levels of metabolic biomarkers. Among men aged < 50 years, MHO had the highest OR for vitamin D deficiency.

Protective actions of vitamin D, anandamide and melatonin during vascular inflammation: Epigenetic mechanisms involved

Vascular inflammation is one of the main activating stimuli of cardiovascular disease and its uncontrolled development may worsen the progression and prognosis of these pathologies. Therefore, the search for new therapeutic options to treat this condition is undoubtedly needed. In this regard, it may be better to repurpose endogenous anti-inflammatory compounds already known, in addition to synthesizing new compounds for therapeutic purposes. It is well known that vitamin D, anandamide, and melatonin are promising endogenous substances with powerful and wide-spread anti-inflammatory properties. Currently, the epigenetic mechanisms underlying these effects are often unknown. This review summarizes the potential epigenetic mechanisms by which vitamin D, anandamide, and melatonin attenuate vascular inflammation. This information could contribute to the improvement in the therapeutic management of multiple pathologies associated with blood vessel inflammation, through the pharmacological manipulation of new target sites that until now have not been addressed.

Beneficial Role of Vitamin D on Endothelial Progenitor Cells (EPCs) in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death in the world. Endothelial progenitor cells (EPCs) are currently being explored in the context of CVD risk. EPCs are bone marrow derived progenitor cells involved in postnatal endothelial repair and neovascularization. A large body of evidence from clinical, animal, and in vitro studies have shown that EPC numbers in circulation and their functionality reflect endogenous vascular regenerative capacity. Traditionally vitamin D is known to be beneficial for bone health and calcium metabolism and in the last two decades, its role in influencing CVD and cancer risk has generated significant interest. Observational studies have shown that low vitamin D levels are associated with an adverse cardiovascular risk profile. Still, Mendelian randomization studies and randomized control trials (RCTs) have not shown significant effects of vitamin D on cardiovascular events. The criticism regarding the RCTs on vitamin D and CVD is that they were not designed to investigate cardiovascular outcomes in vitamin D-deficient individuals. Overall, the association between vitamin D and CVD remains inconclusive. Recent clinical and experimental studies have demonstrated the beneficial role of vitamin D in increasing the circulatory level of EPC as well as their functionality. In this review we present evidence supporting the beneficial role of vitamin D in CVD through its modulation of EPC homeostasis.

Sex differences in the association of vitamin D and metabolic risk factors with carotid intima-media thickness in obese adolescents

BACKGROUND

It has been shown that vitamin D is associated with obesity and the development of atherosclerosis. Less is known about this association among adolescents with obesity.

OBJECTIVES

To determine the association of vitamin D level and metabolic risk factors with carotid intima-media thickness (CIMT) among obese adolescents.

METHODS

We conducted a cross-sectional study among obese children aged 15 to 17 years in Yogyakarta, Indonesia. The association of vitamin D and other metabolic risk factors (triglyceride, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), and insulin resistance using homeostasis model assessment of insulin resistance (HOMA-IR)) with CIMT was explored by multivariable linear regression models.

RESULTS

Out of 156 obese adolescents, 55.8% were boys. Compared to girls, boys had higher BMI z-score, waist circumference, and HDL-cholesterol. After adjustment for age, sex and second-hand smoke exposure, high HOMA-IR, total cholesterol, LDL-cholesterol and triglyceride levels were associated with higher odds of elevated CIMT. In analyses stratified by sex, a similar trend was observed in boys, while none of the risk factors were associated with CIMT in girls. We observed no association between vitamin D and CIMT.

CONCLUSIONS

Hyperinsulinemia, higher total cholesterol and LDL cholesterol were associated with greater odds of elevated CIMT among obese adolescent boys.

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.

Vitamin D deficiency as a risk factor for renal scarring in recurrent urinary tract infections

BACKGROUND

Renal scarring is a serious complication in recurrent urinary tract infections (UTIs). Vitamin D deficiency has also been reported to be a risk factor for UTIs although, to date, no association between vitamin D deficiency and renal scarring has yet been identified. In the present study, it was investigated whether vitamin D deficiency may be a risk factor for renal scarring in patients with recurrent UTIs.

METHODS

The study included patients between the ages of 1 and 18 years who were admitted to the pediatric nephrology department of the center between November 1, 2018 and November 1, 2019 and who were diagnosed with recurrent UTIs. The medical records of the patients were reviewed for the collection of demographic data, vitamin D levels, ultrasonography results and scintigraphic investigations with 99m-technetium dimercaptosuccinic acid (^99m Tc-DMSA). The patients were divided into two groups: those with and without renal scarring, diagnosed via ^99m Tc-DMSA. The vitamin D levels and other parameters of the two groups were compared.

RESULTS

Vitamin D deficiency (<20 ng/mL) was observed in 73.9% of the patients without renal scarring, and in 94.1% of those with renal scarring (P = 0.015). A logistic regression analysis revealed vitamin D deficiency to be an independent risk factor for renal scarring in patients with recurrent UTIs (OR = 0.796 [0.691-0.917]).

CONCLUSIONS

Vitamin D deficiency is found to be a risk factor for renal scarring in patients with recurrent UTIs. Vitamin D treatment may contribute to the prevention of renal scarring in patients with recurrent UTI.

Latent toxoplasmosis and vitamin D concentration in humans: three observational studies

Numerous recent studies show that vitamin D deficiency potentiates various chronic physical and psychiatric disorders and diseases. It has been shown that a similar range of disorders is also associated with latent infection with Toxoplasma gondii (Nicolle et Manceaux, 1908). For instance, among cancer, diabetes and schizophrenia patients, we find a higher prevalence of both toxoplasmosis and vitamin D deficiency. Theoretically, therefore, vitamin D deficiency could be the missing link between toxoplasmosis and these disorders. We tested this hypothesis by searching for decreased vitamin D levels in the serum of subjects infected with T. gondii (furthermore called Toxoplasma-infected subjects) in two cross-sectional and one case-control study. Results of the first cross-sectional study (N = 72) suggest that Toxoplasma-infected neurasthenic patients have non-significantly lower levels of calcidiol than Toxoplasma-free patients (study A: P = 0.26 in women, P = 0.68 in men). However, two other studies (study B: N = 400; study C: N = 191) showed a non-significantly higher concentration of vitamin D in Toxoplasma-infected subjects than in Toxoplasma-free subjects both in men (study B: P = 0.70, study C: P = 0.55) and in women (study B: P = 0.64, study C: P = 0.12). Taken together, our preliminary results thus do not support the hypothesis that toxoplasmosis could be associated with vitamin D decrease.

Unraveling the roles of vitamin D status and melanin during Covid‑19 (Review)

As the coronavirus disease 2019 (COVID‑19) continues to spread worldwide, it has become evident that the morbidity and mortality rates clearly vary across nations. Although several factors may account for this disparity, striking differences within and between populations indicate that ethnicity might impact COVID‑19 clinical outcomes, reflecting the 'color of disease'. Therefore, the role of key biological variables that could interplay with viral spreading and severity indices has attracted increasing attention, particularly among non‑Caucasian populations. Although the links between vitamin D status and the incidence and severity of COVID-19 remain elusive, several lines of emerging evidence suggest that vitamin D signaling, targeting several immune‑mediated pathways, may offer potential benefits at different stages of SARS-CoV-2 infection. Given that the vitamin D status is modulated by several intrinsic and extrinsic factors, including skin type (pigmentation), melanin polymers may also play a role in variable COVID‑19 outcomes among diverse population settings. Moreover, apart from the well‑known limiting effects of melanin on the endogenous production of vitamin D, the potential crosstalk between the pigmentary and immune system may also require special attention concerning the current pandemic. The present review article aimed to shed light on a range of mostly overlooked host factors, such as vitamin D status and melanin pigments, that may influence the course and outcome of COVID‑19.

Association Between Vitamin D Deficiency and COVID-19 Incidence, Complications, and Mortality in 46 Countries: An Ecological Study

Each patient's immune defenses play a major role in mitigating the impact (ie, morbidity and mortality) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19). Vitamin D is an important modulator of the immune system. Although serum 25-hydroxyvitamin D levels can be raised through diet or supplements, most vitamin D in the body is the result of dermal synthesis from ultraviolet radiation. The production of vitamin D in the skin, however, can be limited by latitude, skin-covering clothes, the use of sunblock, and skin pigmentation. Vitamin D deficiency affects a high percentage of the world population. Serum 25-hydroxyvitamin D levels are suboptimal, not only in specific risk groups but also in adults from many countries. Low vitamin D levels, therefore, represent a risk factor for several different pathologies, including SAR-CoV-2. This study used an ecological design to assess the association between vitamin D deficiency and COVID-19 incidence, complications, and mortality across 46 countries. All data were obtained from published sources. The results of the study suggest an association at the population level between the prevalence of vitamin D deficiency and the risk of being infected with COVID-19, severity of the disease, and risk of dying from it.

The antihypertension effect of hydrogen sulfide (H2S) is induced by activating VEGFR2 signaling pathway

AIMS

Previous studies demonstrated that H₂S has an antihypertension effect on hypertension, but the mechanism involved is unclear until now. The aim of the study is to elucidate the effect of H₂S on PH and the mechanism involved.

MAIN METHODS

In this study, GYY4137 (a H₂S donor) were administered to spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) by intraperitoneally injection daily for consecutive 14 days. Systolic blood pressure (SBP), endothelial-dependent relaxation (EDR), plasma malondialdehyde (MDA), superoxide dismutase (SOD), and H₂S levels were measured. Human umbilical vein endothelial cells (HUVECs) were also used to elucidate the mechanism involved in the protect effect of H₂S on the injured vessels.

KEY FINDINGS

Our results showed that GYY4137 normalized the SBP (P < 0.0001), increased EDR (P < 0.01), reduced oxidative stress (increased the content of SOD and reduced the content of MDA) of SHR. Meanwhile, GYY4137 could promote the proliferation (P < 0.01) and migration (P < 0.01) of HUVECs, increase the expression of endothelial NO synthase (eNOS) and Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) both in SHR and HUVECs treated with GYY4137. In addition to the above results, the PIP3/Akt signaling pathway was activated and the expression of caspase 3 was increased by GYY4137. However, all the above effects of GYY4137 were blocked by ZD6474 (a VEGFR2 inhibitor).

SIGNIFICANCE

GYY4137 had a hypotensive and vascular protect effect on PH. This effect might be mediated through upregulating the expression of VEGFR2, which subsequently alleviating oxidant-provoked vascular endothelial dysfunction, and promoting the proliferation and migration of endothelial cells in SHR.

Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection

Although we lack enough evidence to justify supplementing with vitamin D in the prevention and treatment of COVID-19 infection, it is increasingly feasible that this hypothesis is valid. Two general underlying mechanisms should be considered. One would be the anti-infectious and immunomodulatory action that it exerts by improving intercellular barriers by stimulating innate immunity, as well as by modulating adaptive immunity. Also, vitamin D reduces the production of inflammatory cytokines, such as IL-2 and interferon-gamma (INFγ). More recently, multiple pleiotropic effects have been demonstrated on the actions of vitamin D at the anti-inflammatory and immunomodulatory level with positive results in studies with influenza, coronavirus, and other respiratory infections. An inverse relationship between serum vitamin D levels and the prevalence of the respiratory infectious disease has been described. Of interest, another mechanistic approach responds to considering the inhibition of the renin-angiotensin-aldosterone system (RAAS), which is exacerbated in COVID-19 infection because the virus binds to the enzyme ACE2, making more angiotensin II available to cause damage. Vitamin D inhibits mediators of RAAS – present in all cells of the body – and by inhibiting ACE activity and increasing ACE2, it lowers angiotensin II levels. We present studies with proposals for recommended doses of vitamin D, and although a single guideline is not specified, the possible benefits are promising. Finally, the purpose of this review is to share this idea with health professionals to ignite the debate and call for critical reflection, so that it can contribute to the undertaking of more and better clinical designs to validate the benefits of using high doses of vitamin D for the benefit of public health and especially in times of crisis for COVID-19.

Analysis of angiographic characteristics and intervention of vitamin D in type 2 diabetes mellitus complicated with lower extremity arterial disease

AIMS

Previous studies have suggested that type 2 diabetes mellitus with lower extremity arterial disease is related to 25-hydroxyvitamin D deficiency. The purpose of this study is to explore the relation between vitamin D supplementation and the characteristics of type 2 diabetes mellitus complicated with lower extremity arterial disease.

METHODS

The clinical data of 514 patients and 148 healthy subjects treated in the First Hospital of Lanzhou University from January 2012 to June 2019 were collected, including the clinical data, ankle-brachial index, and medical records of lower limb artery angiography. We divided the patients into control group (NC group), type 2 diabetes mellitus group (DM group), lower extremity artery disease in type 2 diabetes mellitus without vitamin D supplement group (DM1 group) and lower extremity artery disease in type 2 diabetes mellitus with vitamin D supplement group (DM2 group). The level of serum 25(OH)D was analyzed and the characteristics of arterial lesions of lower extremities were compared by DSA arteriography in DM1 and DM2 group, respectively.

RESULTS

Compared with the NC group, serum 25(OH)D level decreased in DM group (25.39 ± 4.94 ng/mL vs 19.43 ± 5.98 ng/mL) and significantly decreased in DM1 and DM2 group (14.22 ± 5.64 ng/mL vs 17.36 ± 6.25 ng/mL). However, the level of serum 25(OH)D in the DM2 group was higher than that in the DM1 group. Compared with the DM1 group, the disease rate of the inferior knee artery (65% vs 39.3%) and occlusion rate (11.5% vs 3.7%)were decreased in the DM2 group (P < 0.05). Logistic stepwise regression analysis showed that serum 25(OH)D level was a risk factor for lower extremity arterial disease in patients with type 2 diabetes mellitus (OR = 0.898,95%CI = 0.856-0.942).

CONCLUSIONS

The serum level of 25(OH)D in patients with type 2 diabetes mellitus complicated with lower extremity arterial disease is decreased, and level of 25 (OH) D is related to stenosis and occlusion rate, especially in inferior genicular artery in T2DM complicated with LEAD. A high level of 25(OH)D may be a protective factor in type 2 diabetes with lower extremity arterial disease.

Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection

Although we lack enough evidence to justify supplementing with vitaminD in the prevention and treatment of COVID-19 infection, it is increasingly feasible that this hypothesis is valid. Two general underlying mechanisms should be considered. One would be the anti-infectious and immunomodulatory action that it exerts by improving intercellular barriers by stimulating innate immunity, as well as by modulating adaptive immunity. Also, vitaminD reduces the production of inflammatory cytokines, such as IL-2 and interferon-gamma (INF-γ). More recently, multiple pleiotropic effects have been demonstrated on the actions of vitaminD at the anti-inflammatory and immunomodulatory level with positive results in studies with influenza, coronavirus, and other respiratory infections. An inverse relationship between serum vitaminD levels and the prevalence of the respiratory infectious disease has been described. Of interest, another mechanistic approach responds to considering the inhibition of the renin-angiotensin-aldosterone system (RAAS), which is exacerbated in COVID-19 infection because the virus binds to the enzyme ACE2, making more angiotensinII available to cause damage. VitaminD inhibits mediators of RAAS - present in all cells of the body - and by inhibiting ACE activity and increasing ACE2, it lowers angiotensinII levels. We present studies with proposals for recommended doses of vitaminD, and although a single guideline is not specified, the possible benefits are promising. Finally, the purpose of this review is to share this idea with health professionals to ignite the debate and call for critical reflection, so that it can contribute to the undertaking of more and better clinical designs to validate the benefits of using high doses of vitaminD for the benefit of public health and especially in times of crisis for COVID-19.

Vitamin D and selected cytokine concentrations in postmenopausal women in relation to metabolic disorders and physical activity

Obesity and metabolic disturbances constitute significant health problems in elderly women. Due to the multifactorial background of these disorders, assessing the interaction between risk factors remains a significant part of prevention and health promotion. Studies have illustrated a relationship between low physical activity and vitamin D deficiency with obesity and its complications. Furthermore, vitamin D affects the production of adipokines and the inflammatory response in adipose tissue. The aim of our study was to determine the association between selected adipokines, vitamin D concentrations, physical activity (PA), and visceral adiposity index (VAI) in postmenopausal women. The study sample consisted of 318 ethnically homogenous postmenopausal women aged 50-60. Both anthropometric measurements (BMI, WC, WHR) and biochemical measurements (TC, HDL, LDL, TG, AIP, glucose, insulin, IL-6, TNF-α, adiponectin, leptin) were made, and PA by IPAQ were recorded. Body mass index (BMI), waist-to-hip ratio (WHR), HOMA, atherogenic index of plasma (AIP), and VAI were calculated using the standard formulas. We observed a negative correlation between BMI, WC, insulin, HOMA, and PA. We determined that there is a negative association between leptin and vitamin 25(OH)D concentrations (P = 0.007) and a positive association with adiponectin (P = 0.014). The results of the multiple linear regression analysis indicate that vitamin D and HOMA are independent factors that significantly affect leptin and adiponectin levels, contrary to VAI.

Vitamin D supplementation as a rational pharmacological approach in the COVID-19 pandemic

The COVID-19 pandemic has reached most of the countries worldwide causing death, which often results from an inflammatory storm associated with severe acute respiratory syndrome (SARS). This has prompted researchers to seek specific novel and definitive treatments urgently. In this context, it is interesting to evaluate the preventive and therapeutic effects of existing pharmacological agents that could be useful. In this regard, vitamin D supplementation, particularly in individuals likely to be deficient, may be a promising option. Vitamin D is a hormone that modulates many of the same inflammatory and oxidative signaling pathways triggered during COVID-19. For example, vitamin D suppresses the actions of the renin-angiotensin system, which has a determining role in the pathophysiology of the inflammatory response related to COVID-19. This paper analyzes the evidence that vitamin D supplementation might be a valuable preventive/therapeutic measure in groups at risk for or infected with COVID-19. It also discusses how clinical studies could be best designed to evaluate the possible advantages of vitamin D supplementation for the benefit of public health during the pandemic.

Implications of Oxidative Stress and Potential Role of Mitochondrial Dysfunction in COVID-19: Therapeutic Effects of Vitamin D

Due to its high degree of contagiousness and like almost no other virus, SARS-CoV-2 has put the health of the world population on alert. COVID-19 can provoke an acute inflammatory process and uncontrolled oxidative stress, which predisposes one to respiratory syndrome, and in the worst case, death. Recent evidence suggests the mechanistic role of mitochondria and vitamin D in the development of COVID-19. Indeed, mitochondrial dynamics contribute to the maintenance of cellular homeostasis, and its uncoupling involves pathological situations. SARS-CoV-2 infection is associated with altered mitochondrial dynamics with consequent oxidative stress, pro-inflammatory state, cytokine production, and cell death. Furthermore, vitamin D deficiency seems to be associated with increased COVID-19 risk. In contrast, vitamin D can normalize mitochondrial dynamics, which would improve oxidative stress, pro-inflammatory state, and cytokine production. Furthermore, vitamin D reduces renin–angiotensin–aldosterone system activation and, consequently, decreases ROS generation and improves the prognosis of SARS-CoV-2 infection. Thus, the purpose of this review is to deepen the knowledge about the role of mitochondria and vitamin D directly involved in the regulation of oxidative stress and the inflammatory state in SARS-CoV-2 infection. As future prospects, evidence suggests enhancing the vitamin D levels of the world population, especially of those individuals with additional risk factors that predispose to the lethal consequences of SARS-CoV-2 infection.

The Role of Oxidative Stress in Physiopathology and Pharmacological Treatment with Pro- and Antioxidant Properties in Chronic Diseases

Oxidative stress (OS) has the ability to damage different molecules and cellular structures, altering the correct function of organs and systems. OS accumulates in the body by endogenous and exogenous mechanisms. Increasing evidence points to the involvement of OS in the physiopathology of various chronic diseases that require prolonged periods of pharmacological treatment. Long-term treatments may contribute to changes in systemic OS. In this review, we discuss the involvement of OS in the pathological mechanisms of some chronic diseases, the pro- or antioxidant effects of their pharmacological treatments, and possible adjuvant antioxidant alternatives. Diseases such as high blood pressure, arteriosclerosis, and diabetes mellitus contribute to the increased risk of cardiovascular disease. Antihypertensive, lipid-lowering, and hypoglycemic treatments help reduce the risk with an additional antioxidant benefit. Treatment with methotrexate in autoimmune systemic inflammatory diseases, such as rheumatoid arthritis, has a dual role in stimulating the production of OS and producing mitochondrial dysfunction. However, it can also help indirectly decrease the systemic OS induced by inflammation. Medicaments used to treat neurodegenerative diseases tend to decrease the mechanisms related to the production of reactive oxygen species (ROS) and balance OS. On the other hand, immunosuppressive treatments used in cancer or human immunodeficiency virus infection increase the production of ROS, causing significant oxidative damage in different organs and systems without widely documented exogenous antioxidant administration alternatives.

Hydrogen sulfide improves endothelial dysfunction by inhibiting the vicious cycle of NLRP3 inflammasome and oxidative stress in spontaneously hypertensive rats

OBJECTIVE

To elucidate whether by inhibiting inflammasome and oxidative stress, hydrogen sulfide (H2S) can ameliorate endothelial dysfunction with hypertension.

METHODS

Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were injected with 100 μmol/l sodium hydrosulfide (NaHS) intraperitoneally daily for 16 weeks. SBP and plasma malondialdehyde (MDA) and interleukin 1β (IL-1β) levels were measured. Renal vascular function was used to determine endothelial-dependent contraction (EDC) and endothelial-dependent relaxation (EDR). Protein levels of NOX1, p67, Nrf2, SOD1, CAT, NLRP3, caspase-1 and IL-1β were detected by western blot analysis. Human umbilical vein endothelial cells (HUVECs) were used to confirm the protective role of H2S against angiotensin II (Ang II)-induced cell injury.

RESULTS

Exogenous NaHS administration significantly reduced SBP and ameliorated damaged EDC and EDR. H2S reduced the activation of NLRP3 inflammasome and oxidative stress in SHR. The endothelial protective and antioxidant effect of H2S was abolished by lipopolysaccharide, an inducer of NLRP3 inflammasome. In HUVECs, H2S significantly ameliorated Ang II-induced cellular impairment, NLRP3 inflammasome activity and reactive oxygen species generation. After knocking down Nrf2, the protective effect of H2S was abolished.

CONCLUSION

H2S could inhibit the vicious cycle of oxidative stress and inflammation in hypertension, and then improve endothelial function and ameliorated hypertension. Our results help to reveal the crucial role of H2S in regulating endothelial function, which might be a new tool for treating hypertension.

Lungs as target of COVID-19 infection: Protective common molecular mechanisms of vitamin D and melatonin as a new potential synergistic treatment

COVID-19 pandemic has a high mortality rate and is affecting practically the entire world population. The leading cause of death is severe acute respiratory syndrome as a consequence of exacerbated inflammatory response accompanied by uncontrolled oxidative stress as well as the inflammatory reaction at the lung level. Until now, there is not a specific and definitive treatment for this pathology that worries the world population, especially the older adults who constitute the main risk group. In this context, it results in a particular interest in the evaluation of the efficacy of existing pharmacological agents that may be used for overcoming or attenuating the severity of this pulmonary complication that has ended the lives of many people worldwide. Vitamin D and melatonin could be good options for achieving this aim, taking into account that they have many shared underlying mechanisms that are able to modulate and control the immune adequately and oxidative response against COVID-19 infection, possibly even through a synergistic interaction. The renin-angiotensin system exaltation with consequent inflammatory response has a leading role in the physiopathology of COVID-19 infection; and it may be down-regulated by vitamin D and melatonin in many organs. Therefore, it is also essential to analyze this potential therapeutic association and their relation with RAS as part of this new approach.

Daily and seasonal mitochondrial protection: Unraveling common possible mechanisms involving vitamin D and melatonin

From an evolutionary point of view, vitamin D and melatonin appeared very early and share functions related to defense mechanisms. In the current clinical setting, vitamin D is exclusively associated with phosphocalcic metabolism. Meanwhile, melatonin has chronobiological effects and influences the sleep-wake cycle. Scientific evidence, however, has identified new actions of both molecules in different physiological and pathological settings. The biosynthetic pathways of vitamin D and melatonin are inversely related relative to sun exposure. A deficiency of these molecules has been associated with the pathogenesis of cardiovascular diseases, including arterial hypertension, neurodegenerative diseases, sleep disorders, kidney diseases, cancer, psychiatric disorders, bone diseases, metabolic syndrome, and diabetes, among others. During aging, the intake and cutaneous synthesis of vitamin D, as well as the endogenous synthesis of melatonin are remarkably depleted, therefore, producing a state characterized by an increase of oxidative stress, inflammation, and mitochondrial dysfunction. Both molecules are involved in the homeostatic functioning of the mitochondria. Given the presence of specific receptors in the organelle, the antagonism of the renin-angiotensin-aldosterone system (RAAS), the decrease of reactive species of oxygen (ROS), in conjunction with modifications in autophagy and apoptosis, anti-inflammatory properties inter alia, mitochondria emerge as the final common target for melatonin and vitamin D. The primary purpose of this review is to elucidate the common molecular mechanisms by which vitamin D and melatonin might share a synergistic effect in the protection of proper mitochondrial functioning.

Renoprotective effects of vitamin D3 supplementation in a rat model of metabolic syndrome

PURPOSE

The study aimed to investigate the potential nephroprotective effects of vitamin D3 in metabolic syndrome (MetS) and the molecular basis of the underlying mechanisms of its action.

METHODS

MetS was induced in adult male Wistar rat‏s by adding fructose (10%) to every day drinking water and salt (3%) to the diet. Six weeks after fructose/salt consumption, fasting serum lipid profile and uric acid levels were determined, an oral glucose tolerance test (OGTT) was performed and kidney function was checked. MetS rats were then treated orally with vitamin D3 (10 µg/kg/day) for 6 weeks. At the end of the study period (12 weeks), the OGTT test was reperformed, anthropometrical parameters were measured, urine, blood and tissue samples were collected and the animals were euthanised.

RESULTS

The incidence of MetS was confirmed 6 weeks after fructose/salt consumption, when the rats exhibited significant weight gain, dyslipidemia, hyperuricemia, insulin resistance, hyperinsulinemia and impaired glucose tolerance. After 12 weeks, MetS rats displayed markedly declined renal function alongside with extravagant renal histopathological damages and interstitial fibrosis. Furthermore, significantly enhanced renal oxidative stress and inflammation were manifested. Vitamin D3 supplementation in MetS rats significantly reversed all the above-mentioned deleterious effects.

CONCLUSION

The study has indeed provided mounting evidence of the promising therapeutic potential of vitamin D3 against development and progression of MetS-induced nephropathy. A new insight has been introduced into the crucial role of dipeptidyl peptidase-4 inhibition and sirtuin-1/5'adenosine monophosphate-activated protein kinase activation in the renoprotective effects of vitamin D3.

Vitamin D3 potentiates the renoprotective effects of vildagliptin in a rat model of fructose/salt-induced insulin resistance

Insulin resistance (IR) seemingly plays a role in chronic kidney disease (CKD). The present study has elucidated the crucial interplay of oxidative stress, inflammatory, apoptotic and profibrotic signaling pathways, linking IR to CKD. The study aimed at investigating the pleiotropic nephroprotective effects of either vildagliptin or vitamin D3 in a fructose/salt-induced IR rat model, highlighting the potential molecular mechanisms underlying their action. Another interesting target was to evaluate the potential capacity of vitamin D3 to potentiate the nephroprotective effects of vildagliptin. Indeed, a state of impaired fasting glucose, IR and compensatory hyperinsulinemia, constellating with significant weight gain, atherogenic dyslipidemia and hyperuricemia was established 6 weeks after fructose/salt consumption. IR rats were then treated orally with vildagliptin (10 mg/kg/day), vitamin D3 (10 µg/kg/day) or their combination for a further 6 weeks. By the end of the 12^th week, untreated IR rats displayed significantly declined renal function with parallel interwined renal oxidative stress, inflammatory, apoptotic and profibrotic changes, renal histopathological damages and markedly enhanced collagen fiber deposition. Vildagliptin and vitamin D3 reversed hyperuricemia and exerted a plethora of renal anti-oxidant, anti-inflammatory, anti-apoptotic and anti-fibrotic effects. Our study has introduced a new insight into the role of dipeptidyl peptidase-4 inhibition and silent information regulator 1/5'adenosine monophosphate-activated protein kinase activation in the nephroprotective effects of either agent, elucidating their possible crosstalk with renin angiotensin aldosterone system downregulation. Considering the superadditive renoprotective effects evoked by the combination, vitamin D3 is worth being further investigated as an additional therapeutic agent for preventing IR-induced nephropathy.

Effect of vitamin D supplementation on endothelial function - An updated systematic review with meta-analysis and meta-regression

BACKGROUND AND AIMS

Atherogenesis and endothelial dysfunction contribute to cardiovascular risk and vitamin D has been implemented in endothelial repair. This systematic review, meta-analysis and meta-regression aims to establish the effect of vitamin D supplementation on endothelial function.

METHODS AND RESULTS

To conduct the systematic review we searched the Cochrane Library of Controlled Trials, PubMed, ProQuest and EMBASE for randomized controlled trials that investigated the effects of vitamin D supplementation on flow-mediated dilation (FMD%), pulse wave velocity (PWV), and central augmentation index (AIx). Meta-analysis was based on a random effects model and inverse-variance methods to calculate either mean difference (MD) or standardized mean difference (SMD) as effects sizes. This was followed by meta-regression investigating the effect of baseline vitamin D concentrations, vitamin D dosing and study duration. Risk of bias was assessed using the JADAD scale and funnel plots. We identified 1056 studies of which 26 studies met inclusion criteria for quantitative analysis. Forty-two percent of the 2808 participants had either deficient or insufficient levels of vitamin D. FMD% (MD 1.17% (95% CI -0.20, 2.54), p = 0.095), PWV (SMD -0.09 m/s (95% CI -0.24, 0.07), p = 0.275) and AIx (SMD 0.05% (95% CI -0.1, 0.19), p = 0.52) showed no improvement with vitamin D supplementation. Sub-analysis and meta-regression revealed a tendency for AIx and FMD% to increase as weekly vitamin doses increased; no other significant relationships were identified.

CONCLUSIONS

Vitamin D supplementation showed no improvement in endothelial function. More evidence is required before recommendations for management of endothelial dysfunction can be made.

Alterations on a key nephrogenic/cardiogenic gene expression linked to hypertension development

The elevation of blood pressure produces specific organic lesions, including kidney and cardiac damage. On the other hand, cardiovascular disease usually leads to the development of hypertension. Thus, hypertension could be both a cause and a consequence of cardiovascular disease. Previous studies linked the lack of nitric oxide to cardiovascular abnormalities, including hypertension, arteriosclerosis, myocardial infarction, cardiac hypertrophy, diastolic heart failure, and reduced endothelium-derived hyperpolarizing factor responses, with shorter survival. The lack of this gas also leads to renal/cardiac abnormalities. It is widely known that nephrogenic deficiency is a risk factor for kidney disease. Besides, recent evidence suggests that alterations in WT-1, a key nephrogenic factor, could contribute to the development of hypertension. Moreover, some genes involved in the development of hypertension depend on WT-1. This knowledge makes it essential to investigate and understand the mechanisms regulating the expression of these genes during renal/cardiac development, and hypertension. As a consequence, the most in-depth knowledge of the complex aetiopathogenic mechanism responsible for the hypertensive disease will allow us to propose novel therapeutic tools.

Vitamin D and pulmonary fibrosis: a review of molecular mechanisms

Pulmonary fibrosis is a serious interstitial disease characterized by initial diffuse alveolar inflammation, fibroblast proliferation, ECM accumulation, and the destruction of normal pulmonary tissues, whose etiology remains unknown and therapeutic options remain limited. The prevalence of Vitamin D deficiency is increasing and has been linked to pulmonary fibrosis. In recent years, many studies focused on the mechanistic pathway of Vitamin D in the prevention of fibrosis. This review highlights the current evidence on the molecular mechanisms of Vitamin D in pulmonary fibrosis. We want to provide new clues to the clinical management of pulmonary fibrosis.

Effects of telmisartan and losartan treatments on bone turnover markers in patients with newly diagnosed stage I hypertension

INTRODUCTION

Telmisartan is an angiotensin-II receptor type-1 blocker and a partial agonist for peroxisome proliferator-activated receptor-γ. The aim of this study was to determine the potential effects of telmisartan on bone metabolism and turnover markers.

METHODS

Forty-two patients with newly diagnosed stage I hypertension who were prescribed telmisartan 80 mg/day or losartan 100 mg/day were included. Serum levels of calcium, phosphorus, 25-hydroxy vitamin D, bone-specific alkaline phosphatase, osteocalcin, interleukin 6 and 24-hour urinary N-terminal telopeptide were measured at the beginning and after 12 weeks of treatment.

RESULTS

When treatment arms were evaluated together, significantly increased 25-hydroxy vitamin D levels (p=0.01), and decreased parathormone (PTH) (p<0.001), bone-specific alkaline phosphatase (p=0.01), osteocalcin (p=0.045), urinary N-terminal telopeptide (p<0.001) and interleukin 6 levels (p=0.006) were observed. After eliminating the 25-hydroxy vitamin D effect, significant changes were not observed at any of the parameters. None of the levels of parameters were different between groups.

CONCLUSIONS

Neither telmisartan, despite its partial peroxisome proliferator-activated receptor-γ agonistic effect, nor losartan treatment had significant effects on bone turnover markers in newly diagnosed stage I hypertensive patients.

Dietary Intake of Vitamin D and Its Relation with Blood Pressure in the Elderly Population

Background

Population studies have demonstrated that there is an inverse association between dietary intake of vitamin D and the mean blood pressure in elderly in particular. So, we investigated the correlation between vitamin D intake and the mean blood pressure in the elderly with and without nursing care.

Methods

Based on a cross-sectional design, this study was conducted on 152 old people with and without nursing care. Assessment of the dietary intake of nutrients was done by an expert dietitian using food frequency questionnaire and nutritionist IV software analyzer. Also, the mean blood pressure was extracted from participants' files. The independent samplet-test, Chi-square test, and partial correlation test were used for data analysis.

Results

Mean ± SD age, weight, height, body mass index (BMI) of participants, and the percentage of male/females were 68.7 ± 5.5 years, 63.5 ± 7.9 kg, 162.5 ± 7.1 cm, 24.1 ± 3.4 kg/m² and 48.7/51.3, respectively. Also, a significant negative relationship was observed between vitamin D intake and systolic blood pressure in all participants (P value = 0.028, r = -0.179). There was no significant correlation between vitamin D intake and diastolic blood pressure (P value = 0.558, r = -0.048).

Conclusions

The findings revealed that the nursing care can improve dietary intake of vitamin D in the elderly population. Also, a negative correlation was found between vitamin D intake and systolic blood pressure among all the elderly.