Genomic or Non-Genomic? A Question about the Pleiotropic Roles of Vitamin D in Inflammatory-Based Diseases

Vitamin D (vit D) is widely known for its role in calcium metabolism and its importance for the bone system. However, various studies have revealed a myriad of extra-skeletal functions, including cell differentiation and proliferation, antibacterial, antioxidant, immunomodulatory, and anti-inflammatory properties in various cells and tissues. Vit D mediates its function via regulation of gene expression by binding to its receptor (VDR) which is expressed in almost all cells within the body. This review summarizes the pleiotropic effects of vit D, emphasizing its anti-inflammatory effect on different organ systems. It also provides a comprehensive overview of the genetic and epigenetic effects of vit D and VDR on the expression of genes pertaining to immunity and anti-inflammation. We speculate that in the context of inflammation, vit D and its receptor VDR might fulfill their roles as gene regulators through not only direct gene regulation but also through epigenetic mechanisms

Outdoor Activity in the Daytime, but Not the Nighttime, Predicts Better Mental Health Status During the COVID-19 Curfew in the United Arab Emirates

Background: The COVID-19 pandemic and the associated infection prevention and control measures had a negative impact on the mental health of many people. In the United Arab Emirates (UAE), infection control measures implemented after March 24th, 2020, placed necessary restrictions on people's freedom of movement. Aim: This study aimed to assess the association between levels of daytime vs. nighttime outdoor activity and mental health among a sample of UAE residents during the lockdown period. Method: An opportunity sample of 245 participants completed an online survey assessing levels of depression, somatic symptoms, daytime and nighttime activity levels. Results: Multivariate logistic regression revealed that daytime activity, but not nighttime activity, was associated with a lower risk of clinically significant depressive and somatic symptomatology. Conclusion: The association of better mental health with daytime not nighttime outdoor activity could be possibly attributed to vitamin D, but further studies are needed to confirm this speculation

Vitamin D status and blood pressure in children and adolescents: a systematic review of observational studies

Background: Childhood hypertension is a growing public health problem. Simultaneously, hypovitaminosis D is widespread in this population and could be associated with hypertension. This study systematically reviewed the literature on the relationship between vitamin D status and blood pressure (BP) in children and adolescents.Methods: Following the PRISMA guidelines, PUBMED, MEDLINE, CINAHL, EMBASE, Cochrane Library, and and the gray literature without language or time restrictions were searched. We included observational studies, assessed their risk of bias, and extracted data on population characteristics, vitamin D status and BP measurements, and the association between the two variables. A narrative analysis of the studies was performed.Results: In total, 85 studies were included. Prospective cohort studies showed no association between vitamin D and BP, and generally, they were flawed. Also, the majority of non-prospective cohort studies (cross-sectional, retrospective, case-control) did not report an association between vitamin D and BP. They were mostly flawed regarding BP measurement and adjusting to potential confounders.Conclusion: The results on the relationship between vitamin D status and BP in children and adolescents varied between the studies, and mainly pointed towards lack of association

Vitamin D receptor gene polymorphisms among Emirati patients with type 2 diabetes mellitus

© 2017 Elsevier Ltd At a prevalence rate close to 19.5%, the UAE has one of the highest rates of Type 2 Diabetes Mellitus (T2DM) in the world. Genome wide association studies (GWAS) have led to the identification of several genetic variants that are associated with T2DM. Recently, genes involved in vitamin D metabolism have gained interest because of the association between vitamin D deficiency (VDD) and increased risk for T2DM. Among these, the Vitamin D receptor (VDR) gene is a good candidate for T2DM susceptibility. The aim of this study was to investigate the association between VDR polymorphisms and T2DM among a representative sample of the Emirati population. In this cross sectional study, two hundred and sixty four patients with T2DM and ninety-one healthy controls were enrolled. The study population was genotyped for the three VDR gene mutations, TaqI (rs731236), FokI (rs2228570) and BsmI (rs1544410). VDR alleles and haplotypes were compared between patients and their healthy controls. The mean age of the T2DM cohort was 60 ± 11.59 years and 48.21 ± 12.17 years for the healthy controls. The G-allele and GG genotype of rs2228570 and T-allele and TT genotype of rs1544410 SNPs were associated with T2DM. In regards to T2DM-related metabolic complications, the AG and GG genotypes of rs731236 were significantly associated with higher total cholesterol (p = 0.011) and LDL-cholesterol (p = 0.009) levels in the patients with T2DM. In contrast, the CT genotype of rs1544410 was significantly associated with lower BMI (p = 0.031) and the TT genotype was associated with lower LDL-cholesterol level (p = 0.007). The frequency of AAT and GGC haplotypes was also different between groups (p = 0.014; p = 0.032, respectively), implying that these haplotypes of the VDR gene are associated with the susceptibility to T2DM in the Emirati population. To conclude, an association between SNPs in the VDR gene (except for rs731236) and T2DM per se was demonstrated. The rs731236 variant was shown to be associated with high cholesterol and LDL-cholesterol levels in T2DM patients, while rs1544410 was associated with lower BMI and lower LDL cholesterol levels. Our results imply that alleles and haploypes of the VDR gene are associated with the susceptibility to T2DM in the Emirati population

Genomic or Non-Genomic? A Question about the Pleiotropic Roles of Vitamin D in Inflammatory-Based Diseases

Vitamin D (vit D) is widely known for its role in calcium metabolism and its importance for the bone system. However, various studies have revealed a myriad of extra-skeletal functions, including cell differentiation and proliferation, antibacterial, antioxidant, immunomodulatory, and anti-inflammatory properties in various cells and tissues. Vit D mediates its function via regulation of gene expression by binding to its receptor (VDR) which is expressed in almost all cells within the body. This review summarizes the pleiotropic effects of vit D, emphasizing its anti-inflammatory effect on different organ systems. It also provides a comprehensive overview of the genetic and epigenetic effects of vit D and VDR on the expression of genes pertaining to immunity and anti-inflammation. We speculate that in the context of inflammation, vit D and its receptor VDR might fulfill their roles as gene regulators through not only direct gene regulation but also through epigenetic mechanisms

Change in Vitamin D Levels Occurs Early after Antiretroviral Therapy Initiation and Depends on Treatment Regimen in Resource-Limited Settings

STUDY BACKGROUND Vitamin D has wide-ranging effects on the immune system, and studies suggest that low serum vitamin D levels are associated with worse clinical outcomes in HIV. Recent studies have identified an interaction between antiretrovirals used to treat HIV and reduced serum vitamin D levels, but these studies have been done in North American and European populations. METHODS Using a prospective cohort study design nested in a multinational clinical trial, we examined the effect of three combination antiretroviral (cART) regimens on serum vitamin D levels in 270 cART-naïve, HIV-infected adults in nine diverse countries, (Brazil, Haiti, Peru, Thailand, India, Malawi, South Africa, Zimbabwe and the United States). We evaluated the change between baseline serum vitamin D levels and vitamin D levels 24 and 48 weeks after cART initiation. RESULTS Serum vitamin D levels decreased significantly from baseline to 24 weeks among those randomized to efavirenz/lamivudine/zidovudine (mean change: -7.94 [95% Confidence Interval (CI) -10.42, -5.54] ng/ml) and efavirenz/emtricitabine/tenofovir-DF (mean change: -6.66 [95% CI -9.40, -3.92] ng/ml) when compared to those randomized to atazanavir/emtricitabine/didanosine-EC (mean change: -2.29 [95% CI -4.83, 0.25] ng/ml). Vitamin D levels did not change significantly between week 24 and 48. Other factors that significantly affected serum vitamin D change included country (p<0.001), season (p<0.001) and baseline vitamin D level (p<0.001). CONCLUSION Efavirenz-containing cART regimens adversely affected vitamin D levels in patients from economically, geographically and racially diverse resource-limited settings. This effect was most pronounced early after cART initiation. Research is needed to define the role of Vitamin D supplementation in HIV care

RNA Interference in Protozoan Parasites: Achievements and Challenges ▿

Protozoan parasites that profoundly affect mankind represent an exceptionally diverse group of organisms, including Plasmodium, Toxoplasma, Entamoeba, Giardia, trypanosomes, and Leishmania. Despite the overwhelming impact of these parasites, there remain many aspects to be discovered about mechanisms of pathogenesis and how these organisms survive in the host. Combined with the ever-increasing availability of sequenced genomes, RNA interference (RNAi), discovered a mere 13 years ago, has enormously facilitated the analysis of gene function, especially in organisms that are not amenable to classical genetic approaches. Here we review the current status of RNAi in studies of parasitic protozoa, with special emphasis on its use as a postgenomic tool