Search Results (803)

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the etiologic agent that causes the coronavirus disease (COVID-19) identified in Wuhan, in 2019. Men are more prone to developing severe manifestations than women, suggesting a possible crucial role of sex hormones. 17,β-Estradiol (E2) and 1,25 α dihydroxyvitamin D₃ (calcitriol) act upon gene pathways as immunomodulators in several infectious respiratory diseases. In this study, we aimed to evaluate the influence of E2 and calcitriol on the VSV-based pseudovirus SARS-CoV-2 and SARS-CoV-2 infection in vitro. We infected Vero E6 cells with the recombinant VSV-based pseudovirus SARS-CoV-2 and the SARS-CoV-2 viruses according to the pre-treatment and pre–post-treatment models. The Angiotensin-Converting Enzyme 2 (ACE2) and Vitamin D Receptor (VDR) gene expression did not change under different treatments. The VSV-based pseudovirus SARS-CoV-2 infection showed a significant decrease in the focus-forming unit count in the presence of E2 and calcitriol (either alone or in combination) in the pre-treatment model, while in the pre–post-treatment model, the infection was inhibited only in the presence of E2. Th SARS-CoV-2 infection highlighted a decrease in viral titres in the presence of E2 and calcitriol only in the pre–post-treatment model. 17,β-Estradiol and calcitriol can exert an inhibitory effect on SARS-CoV-2 infections, demonstrating their protective role against viral infections. Full article

Sarcopenia is a progressive age-related musculoskeletal disorder characterized by loss of muscle mass, strength, and physical performance, contributing to functional decline and increased risk of disability. Emerging evidence suggests that vitamin D (Vit D) plays a pivotal role in skeletal muscle physiology beyond its classical functions in bone metabolism. This review aims to critically analyze the relationship between serum Vit D levels and sarcopenia in older adults, focusing on pathophysiological mechanisms, diagnostic criteria, clinical evidence, and preventive strategies. An integrative narrative review of observational studies, randomized controlled trials, and meta-analyses published in the last decade was conducted. The analysis incorporated international diagnostic criteria for sarcopenia (EWGSOP2, AWGS, FNIH, IWGS), current guidelines for Vit D sufficiency, and molecular mechanisms related to Vit D receptor (VDR) signaling in muscle tissue. Low serum 25-hydroxyvitamin D levels are consistently associated with decreased muscle strength, reduced physical performance, and increased prevalence of sarcopenia. Although interventional trials using Vit D supplementation report variable results, benefits are more evident in individuals with baseline deficiency and when combined with protein intake and resistance training. Mechanistically, Vit D influences muscle health via genomic and non-genomic pathways, regulating calcium homeostasis, mitochondrial function, oxidative stress, and inflammatory signaling. Vit D deficiency represents a modifiable risk factor for sarcopenia and functional impairment in older adults. While current evidence supports its role in muscular health, future high-quality trials are needed to establish optimal serum thresholds and dosing strategies for prevention and treatment. An individualized, multimodal approach involving supplementation, exercise, and nutritional optimization appears most promising. Full article

Environmental exposure to per- and polyfluoroalkyl substances (PFASs) has been increasingly associated with skin disorders, including atopic dermatitis (AD); however, the underlying molecular mechanisms remain unclear. This study aimed to evaluate the effects of perfluorononanoic acid (PFNA) and perfluorooctanoic acid (PFOA)—two widely detected PFASs—on epidermal function and gene expression in Human Epithelial Keratinocyte, neonatal (HEKn). We assessed cell viability, morphology, and transcriptomic changes using in vitro assays and RNA-seq analysis from a neonatal cohort. PFASs induced dose-dependent cytotoxicity and downregulation of barrier-related genes. Ingenuity pathway analysis identified calcitriol as a suppressed upstream regulator. Functional validation revealed that calcitriol partially reversed the PFAS-induced suppression of antimicrobial peptide genes. These findings support the hypothesis that PFASs may contribute to AD-like skin pathology by impairing vitamin D receptor signaling and antimicrobial defense, and calcitriol demonstrates potential as a protective modulator. This study provides mechanistic insights into the impact of environmental toxicants on skin homeostasis and suggests a potential protective role for calcitriol in PFAS-induced skin barrier damage. Full article

Recent breakthroughs in cancer immunotherapy have shown remarkable success, yet treatment efficacy varies significantly among individuals. Emerging evidence highlights the gut microbiota as a key modulator of immunotherapy response, while vitamin D (VD), an immunomodulatory hormone, has garnered increasing attention for its potential interactions with gut microbiota and immunotherapy outcomes. However, the precise mechanisms and clinical applications of VD in this context remain controversial. This study systematically analyzed peer-reviewed evidence from PubMed, Scopus, Web of Science, PsycINFO, and MEDLINE (January 2000–May 2025) to investigate the complex interplay among VD, gut microbiota, and cancer immunotherapy. This review demonstrates that VD exerts dual immunomodulatory effects by directly activating immune cells through vitamin D receptor (VDR) signaling while simultaneously reshaping gut microbial composition to enhance antitumor immunity. Clinical data reveal paradoxical outcomes: optimal VD levels correlate with improved immunotherapy responses and reduced toxicity in some studies yet are associated with immunosuppression and poorer survival in others. The bidirectional VD–microbiota interaction further complicates this relationship: VD supplementation enriches beneficial bacteria, which reciprocally regulate VD metabolism and amplify immune responses, whereas excessive VD intake may disrupt this balance, leading to dysbiosis and compromised therapeutic efficacy. These findings underscore the need to elucidate VD’s dose-dependent and microbiota-mediated mechanisms to optimize its clinical application in immunotherapy regimens. Future research should prioritize mechanistic studies of VD’s immunoregulatory pathways, personalized strategies accounting for host–microbiota variability, and large-scale clinical trials to validate VD’s role as an adjuvant in precision immunotherapy. Full article

Background/Objectives: Adequate vitamin D levels are essential for various physiological functions, including cell growth, immune modulation, metabolic regulation, DNA repair, and overall health span. Despite its proven cost-effectiveness, widespread deficiency persists due to inadequate supplementation and limited sunlight exposure. Methods: This systematic review (SR) examines the relationship between vitamin D and the reduction of cancer risk and mortality, and the mechanisms involved in cancer prevention. This SR followed the PRISMA and PICOS guidelines and synthesized evidence from relevant studies. Results: Beyond genomic actions via calcitriol [1,25(OH)₂D]-receptor interactions, vitamin D exerts cancer-protective effects through mitigating inflammation, autocrine, paracrine, and membrane signaling. The findings reveal a strong inverse relationship between serum 25(OH)D levels and the incidence, metastasis, and mortality of several cancer types, including colon, gastric, rectal, breast, endometrial, bladder, esophageal, gallbladder, ovarian, pancreatic, renal, vulvar cancers, and both Hodgkin’s and non-Hodgkin’s lymphomas. While 25(OH)D levels of around 20 ng/mL suffice for musculoskeletal health, maintaining levels above 40 ng/mL (100 nmol/L: range, 40–80 ng/mL) significantly lowers cancer risks and mortality. Conclusions: While many observational studies support vitamin D’s protective role in incidents and deaths from cancer, some recent mega-RCTs have failed to demonstrate this. The latter is primarily due to critical study design flaws, like recruiting vitamin D sufficient subjects, inadequate dosing, short durations, and biased designs in nutrient supplementation studies. Consequently, conclusions from these cannot be relied upon. Well-designed, adequately powered clinical trials using appropriate methodologies, sufficient vitamin D₃ doses, and extended durations consistently demonstrate that proper supplementation significantly reduces cancer risk and markedly lowers cancer mortality. Full article

Previous research has linked both endothelial protein changes and vitamin D with infertility. This study was undertaken to investigate the association of proteins associated with endothelial function and vitamin D status in the luteal phase at day 21 in a group of non-obese women prior to in vitro fertilization (IVF) with either unexplained infertility (UI) or male factor infertility (MFI). Twenty-five non-obese Caucasian women from a UK academic center with MFI (n = 14) and UI (n = 11) were recruited. Blood was withdrawn at day 21 of the menstrual cycle at the time of mock embryo transfer. Vitamin D parameters were measured by tandem mass spectroscopy. Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement was undertaken for 20 protein markers of endothelial dysfunction. Baseline demographics did not differ between groups and parameters of response following IVF did not differ. Vitamins D₂ and D₃, and 1,25 Vitamin D₃ did not differ between groups. In UI, markers of endothelial activation/dysfunction were investigated; vascular cell adhesion molecule 1 (VCAM-1) decreased and this is associated with endothelial stress; vascular endothelial growth factor (VEGF) decreased and this may suggest impaired endometrial angiogenesis; while intercellular adhesion molecule 1 (ICAM-3) increased (p < 0.05) and is associated with increased immunological activity. A marker of vascular integrity, angiopoietin-1, increased while soluble angiopoietin-1 receptor (sTie-2) decreased (p < 0.05), suggesting increased vascular development. Endothelial markers of inflammation, coagulation, and endothelial progenitor cells were unchanged. Vitamin D and its metabolites show no relationship to UI, but endothelial activation/dysfunction and vascular integrity changes in VCAM-1, VEGF, sICAM-3, angiopoietin-1, and sTie-2 may contribute to UI, though the mechanisms through which they work require further evaluation; however, these protein changes have been associated with endometriosis, raising the suggestion that subclinical/undiagnosed endometriosis may have contributed to UI in these subjects. Full article

Background: Vitamin D is increasingly recognized not only for its role in skeletal development but also for its immunomodulatory and gastrointestinal effects. Maternal and neonatal vitamin D deficiency (VDD) has been associated with alterations in gut microbiota, impaired intestinal barrier integrity, and increased susceptibility to inflammatory conditions in neonates. However, the exact mechanisms linking perinatal vitamin D status to neonatal gastrointestinal morbidity remain incompletely understood. Methods: This review synthesizes current evidence (2015–2024) from clinical studies, animal models, and mechanistic research on the impact of VDD during pregnancy and the neonatal period on gastrointestinal health. Databases such as PubMed, Scopus, and Web of Science were systematically searched using keywords, including “vitamin D”, “neonate”, “gut microbiome”, “intestinal barrier”, and “necrotizing enterocolitis”. Results: Emerging data suggest that VDD in utero and postnatally correlates with dysbiosis, increased intestinal permeability, and elevated inflammatory responses in neonates. Notably, low 25(OH)D levels in mothers and newborns have been linked with a higher incidence of necrotizing enterocolitis (NEC), delayed gut maturation, and altered mucosal immunity. Vitamin D appears to modulate the expression of tight junction proteins, regulate antimicrobial peptides, and maintain microbial diversity through the vitamin D receptor (VDR). Conclusions: Understanding the gastrointestinal implications of early-life VDD opens a potential window for preventive strategies in neonatal care. Timely maternal supplementation and targeted neonatal interventions may mitigate gut-related morbidities and improve early-life health outcomes. Further longitudinal and interventional studies are warranted to clarify causality and optimal intervention timing. Full article

Sepsis acts as the leading cause of mortality in intensive care units, characterized by life-threatening organ dysfunction due to a dysregulated host response to infection. Vitamin D (VD) pleiotropic functions were demonstrated in different biological processes, including inflammation and immunity. VD receptor (VDR) is a member of the nuclear receptor superfamily, involved in immunoregulation and resistance to infections. Previous studies have demonstrated that VD deficiency is a potential risk factor for sepsis development, which may be regulated by VDR-related physiological processes. In this review, we present a comprehensive overview of the roles of VD and VDR in sepsis, focusing on immune modulation, anti-inflammatory and anti-infective responses, oxidative stress regulation, gut microbiome enhancement, vascular endothelial cell modulation, and antiplatelet activity. We also discuss recent advances in clinical research on VD/VDR in sepsis, considering the clinical implications and potential interventions of VD analogs and VDR ligands in treatment. Despite its challenges, VD holds potential for personalized sepsis interventions. Additionally, VD/VDR may serve as a promising bidirectional immunomodulator, capable of addressing both hyperinflammatory and immunosuppressive phases of sepsis, yet require systematic investigations into its dynamic states and functions across different sepsis phases. Ongoing study and evidence-based guidelines are crucial to maximize its therapeutic benefits and improve clinical outcomes. Full article

Background: Vitamin D has anti-inflammatory and immunomodulatory properties that may influence the pathophysiology of endometriosis. This study investigated the association between vitamin D levels and endometriosis, and vitamin D receptor (VDR) expression in endometriotic tissue. Methods: A cross-sectional study was conducted involving 36 patients with endometriosis and 72 healthy control women, matched for age and BMI. Serum 25-hydroxyvitamin D levels were measured and categorized into four statuses (normal, insufficiency, deficiency, and severe deficiency). Endometriotic tissue samples were examined for VDR expression using immunohistochemistry and qualitatively quantified using histo-scores (H-scores). Endometriosis severity was assessed using the revised criteria of the American Society for Reproductive Medicine (rASRM). Results: No statistically significant difference in vitamin D levels between the groups (20.45 vs. 21.10 ng/dL, p = 0.190) was observed, even after adjusting for residence, body sunscreen use, pregnancy, and contraceptive use. VDR expression exhibited significantly higher H-scores in endometriotic epithelial cells than in stromal cells (209.51 vs. 73.32; p < 0.001). Additionally, the VDR H-score in both cell compartments showed no significant difference according to vitamin D status. No statistically significant association was found between vitamin D levels, VDR expression, or disease severity. The odds of severe endometriosis were 2.17 (95% CI: 0.14–33.80) for vitamin D insufficiency and 4.33 (95% CI: 0.24–115.67) for deficiency compared with normal vitamin D. Conclusions: There was no statistically significant association between vitamin D levels and endometriosis and VDR. Full article

Vitamin D deficiency is widespread. It increases the risk of several diseases. Therefore, researchers have long studied the factors that influence vitamin D levels in the body. These include its metabolism, catabolism, transport and binding of vitamin D to the receptor VDR. Currently, an increasing number of studies are focusing on genetic factors. Variations in vitamin D levels, including vitamin D deficiency, are under substantial genetic control. There is a reciprocity between the vitamin D system and epigenetic mechanisms. Vitamin D metabolism, on the one hand, is regulated by epigenetic mechanisms and, on the other hand, is involved in regulating epigenetic events. To appraise recent advances in nutrigenomics with its application in public health, several databases, including PubMed, Scopus and Web of Science, were investigated in detail. Nutri-epigenetics deals with the interplay between dietary components and the possible resulting changes in the epigenome. There is, therefore, great potential for the development of nutri-epigenetics. The purpose of the narrative review is to highlight the genetic aspects of vitamin D, its receptor VDR and vitamin D-related gene polymorphisms with a particular focus on vitamin D gene regulation. Particular attention is paid to the vitamin D response index. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disease marked by impaired barrier function and immune dysregulation. This study explores transcriptomic differences between lesional (IL) and perilesional (PL) skin in patients with AD, focusing on barrier-related and vitamin D-associated pathways. RNA sequencing was performed on matched IL and PL biopsies from 21 adults with moderate-to-severe AD. Differential gene expression, pathway enrichment, and correlation analysis with clinical variables were assessed. A total of 8817 genes were differentially expressed in IL versus PL skin (padj < 0.05). Among genes with the highest level of dysregulation, strong upregulation was observed for inflammatory mediators (IL-19, IL-8, CXCL6), and epidermal remodeling and barrier-disrupting genes (MMP1, GJB2). The vitamin D pathway genes CYP27B1 and CYP24A1 were also significantly upregulated. In contrast, key barrier-related genes such as FLG2 and CGNL1 were markedly downregulated. While some patterns in gene expression showed subgroup-specific trends, no independent clinical predictors emerged in multivariate models. Reactome pathway analysis revealed the enrichment of pathways involved in keratinization, cornified envelope formation, IL-4/IL-13 signaling, chemokine activity, and antimicrobial responses, highlighting coordinated structural and immunologic dysregulation in lesional skin. Lesional skin in AD displays a distinct transcriptomic profile marked by barrier impairment, heightened inflammatory signaling, and activation of vitamin D-related pathways. These findings provide the first RNA-seq-based comparison of IL and adjacent PL skin in AD. We identify subclinical activation in PL skin and vitamin D pathway upregulation with disrupted gene coordination in lesions. These findings enhance our understanding of the molecular mechanisms underlying inflammation in AD. Full article

Background/Objectives: Endplate lesions of the lumbar spine are often asymptomatic and frequently observed incidentally by radiological assessment. Variants in the vitamin D receptor gene (VDR) and an increase in some biochemical markers related to the osteo-cartilaginous metabolism were found in patients with endplate lesions. The aim of this study was to identify biochemical and genetic markers putatively associated with the presence of endplate lesions of the lumbar spine. Methods: Quantification of circulating bone remodeling proteins was obtained from 10 patients with endplate lesions and compared with age- and sex-matched controls. Whole exome sequencing (WES) was performed on patient genomic DNA using the Novaseq 6000 platform (Illumina, San Diego, CA, USA), obtaining a median read depth of 117×–200×, with ≥98% of regions covering at least 20×. The sequencing product was aligned to the reference genome (GRCh38.p13-hg38) and analyzed with Geneyx software. Results: We observed modifications in the levels of circulating proteins involved in bone remodeling and angiogenesis. We identified variants of interest in aggrecan (ACAN), bone morphogenetic protein 4 (BMP4), cytochrome P450 family 3 subfamily A member 4 (CYP3A4), GLI family zinc finger 2 (GLI2), heparan sulfate proteoglycan 2 (HSPG2), and mesoderm posterior bHLH transcription factor 2 (MESP2). VDR polymorphism (rs2228570) was present in nine patients, with the homozygotic ones having more severe endplate lesions and higher levels of the analyzed circulating markers in comparison with heterozygotic patients. Conclusions: These data represent interesting evidence of genetic variants, particularly in VDR, and altered levels of circulating markers of bone remodeling associated with endplate lesions, which should be confirmed in a larger population. The hypothesis suggested by our results is that the endplate lesions could be the consequence of an altered ossification mechanism at the vertebral level. Full article

Bile acids (BAs), essential for lipid metabolism and fat-soluble vitamin absorption, also act as signaling molecules that regulate immune homeostasis. This review focuses on the roles of four key BA-activated receptors, farnesoid X receptor (FXR), G protein-coupled bile acid receptor 1 (GPBAR1), liver X receptors (LXRs), and vitamin D receptor (VDR), in modulating the functions of monocytes-macrophages, and dendritic cells (DCs). The biological synthesis, transport, and metabolism of BAs were discussed and highlighted the feedback mechanisms regulating the synthesis and enterohepatic circulation of BAs. Each receptor’s role in shaping immune responses is detailed, including their function in inflammation, apoptosis, phagocytosis, and pathogen clearance. FXR and GPBAR1 activation generally exhibits anti-inflammatory effects, while LXR and VDR modulate a more nuanced interplay between immune responses and lipid homeostasis. We also explored the cross-talk between BA-activated receptors and Toll-like receptors, providing a comprehensive understanding of the complex interplay between BA signaling and innate immunity. This review culminates by highlighting the therapeutic potential of targeting these receptors for the treatment of inflammatory and autoimmune diseases. Full article

The active form of vitamin D₃, 1α,25-dihydroxyvitamin D₃ (1,25D₃), regulates a number of physiological and pathological processes, including cell proliferation and differentiation. Thousands of analogues of 1,25D₃ have been developed with the aim of selective effects for medical use. Here we describe the synthesis of two new unconventional vitamin D analogues bearing A-ring modifications with ortho-carborane (dicarba-o-closo-1,2-dodecaborane) units. The ligands function as agonists for VDR with similar antiproliferative activities as 1,25D₃. Whereas mice treated with the analogues 4 and 5 exhibited similar hypercalcemic activities as 1,25D₃, only compound 4 and 1,25D₃ induced the strong activation of CYP24A1 mRNA expression but not compound 5. Full article

Diabetic foot ulcers (DFUs) constitute a severe and debilitating complication of diabetes, imposing a substantial global health burden due to their intricate pathophysiology and impaired wound healing processes. Vitamin D deficiency is highly prevalent among diabetic populations, and accumulating evidence indicates its potential involvement in the pathogenesis and prognosis of DFUs. This review comprehensively explores the diverse roles of vitamin D in DFUs, encompassing its molecular mechanisms such as immunomodulation, promotion of angiogenesis, neuroprotection, and induction of antimicrobial peptides, as well as the metabolic characteristics associated with various vitamin D forms and compromised vitamin D receptor (VDR) signaling pathways. Although robust observational studies have established an association between vitamin D deficiency and adverse outcomes in DFUs, the clinical validation of supplementation efficacy through randomized controlled trials (RCTs) remains constrained by limitations such as small sample sizes, heterogeneity in study protocols, and insufficient long-term follow-up. This highlights the critical need for large-scale, high-quality studies to ascertain optimal treatment regimens and to cater to individualized patient requirements, particularly for individuals with obesity or those with renal impairments. Innovative strategies, such as the topical administration of vitamin D through intelligent delivery systems leveraging advanced biomaterials like nanofibers and hydrogels, exhibit substantial preclinical potential in enhancing stability, achieving targeted controlled release, and augmenting local biological effects, including the induction of antimicrobial peptides. Nevertheless, significant challenges persist in conclusively establishing clinical efficacy, comprehensively elucidating the underlying mechanisms, ensuring the safe translation of novel delivery systems, and developing personalized therapeutic strategies. The future success of these interventions hinges on meticulous research and interdisciplinary collaboration to seamlessly integrate validated vitamin D-based interventions into a comprehensive multidisciplinary management framework for DFUs, thereby holding promise for improving the clinical outcomes of this debilitating condition. Full article