1alpha,25-Dihydroxyvitamin d3 has a direct effect on naive CD4(+) T cells to enhance the development of Th2 cells

The effects of the MTHFR 677C>T (rs1801133) genetic variant on susceptibility and disability worsening in multiple sclerosis patients are mediated by homocysteine

BACKGROUND

Interactions between genetic and environmental variables contribute to the autoimmune inflammatory process in multiple sclerosis (MS). Elevated homocysteine levels, and vitamin D, vitamin B12, and folate deficiencies are some of the environmental factors associated with the pathogenesis of MS. Considering that the relationship between MTHFR 677C>T (rs1801133) genetic variant, homocysteine, and folate in patients with MS remains unclear and that their role were not extensively explored in the clinical course of the disease, we investigated whether this variant and plasma homocysteine and folate levels are associated with MS susceptibility, disability, disability progression, and inflammatory biomarkers.

METHODS

The case-control study included 163 patients with MS categorized using the Expanded Disability Status Scale (EDSS) as mild (EDSS<3) and moderate/high (EDSS≥3) disability, and 226 healthy controls (HC). Disability progression was evaluated using Multiple Sclerosis Severity Score (MSSS) and the MTHFR 677C>T variant was genotyped using real time polymerase chain reaction. The plasma levels of some inflammatory biomarkers were determined. Two new composed scores were proposed: the first, namely as inflammatory activity index (IAI), was entered as a latent vector extracted from the macrophage M1 + T helper (Th)1 + Th17 + Th2 + T regulatory (Treg) cytokines, + tumor necrosis factor (TNF)-α+ soluble TNF receptor (sTNFR)-1 + sTNFR2. The second score, namely MS-severity index was entered as a latent vector extracted from the EDSS + MSSS scores + MS diagnosis.

RESULTS

Patients with MS showed higher homocysteine and folate than controls (p < 0.001); homocysteine, and the M1, Th1, Th17, and Th2 Treg cytokine values were different between the three study groups and increased from HC to MS patients with mild disability and to MS patients with moderate/high disability (p < 0.0001). The levels of TNF-α and their soluble receptors sTNFR1 and sTNFR2 were higher in MS patients with EDSS≥3 than in the two other groups (EDSS<3 and HC) (p < 0.001). There was no association between the MTHFR 677 C > T genotypes and MS susceptibility, disability and disability progression (p > 0.05). Moreover, 21.8 % of the disability variance was explained by age, IAI and C-reactive protein (CRP) (all positively associated); 10.9 % of the disability progression variance was predicted by IAI and CRP (both positively) and 25-hydroxyvitamin D (negatively), whereas 54.4 % of the severity index (MS-EDSS-MSSS) was explained by the regression on age, IAI, homocysteine, folate, and CRP (all positively), and adiponectin, body mass index, and 25-hydroxyvitamin D (all negatively), female sex, and the MTHFR 677 TT genotype. In patients and controls, 16.6 % of the variance in the homocysteine was explained by the MTHFR 677 TT genotype and age (both positively), folate (negatively) and male sex.

CONCLUSION

The MTHFR 677C>T variant has an indirect effect on the increase in disability in patients with MS, which also depends on factors such as age, sex, ad folate status.

Associations of serum 25-hydroxyvitamin D with hsCRP and other novel inflammatory biomarkers in children: a cross-sectional study

OBJECTIVE

Previous studies have shown the anti-inflammatory effect of 25-hydroxyvitamin D (25(OH)D) and the crucial roles of high-sensitive C reactive protein (hsCRP) and novel inflammatory markers (red blood cell distribution width-platelet count ratio (RDWPCR), mean platelet volume-platelet count ratio (MPVPCR), neutrophil-lymphocyte ratio (NLR) and white blood cell-neutrophil ratios (WBCNR)) in several diseases, but scarce data explored the associations of 25(OH)D with hsCRP and novel inflammatory markers. This study aimed to investigate these associations in children.

DESIGN

Cross-sectional study.

SETTING

Children in China.

PARTICIPANTS

10141 children (mean age 14.6 months) were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

HsCRP, red blood cell distribution width, platelet count, mean platelet volume, neutrophil, lymphocyte and white blood cell were measured.

RESULTS

Overall, serum 25(OH)D was inversely associated with hsCRP and novel inflammatory biomarkers. In multivariable analysis, serum 25(OH)D was inversely associated with hsCRP and novel inflammatory biomarkers (Q quartile (Q) 4 vs Q1: 1129.75 vs 2090.99 for hsCRP; 4246.94 vs 6829.89 for RDWPCR; 4863.57 vs 5545.66 for MPVPCR; 4345.76 vs 6507.46 for NLR; 2418.84 vs 2868.39 for WBCNR). Similar results also were observed in stratified analyses by sex (boys and girls). Moreover, serum 25(OH)D was inversely associated with elevated inflammation levels. After adjustment for other potential covariates, inverse associations between serum 25(OH)D and elevated inflammation levels were still observed. The corresponding ORs (95% CI) were 0.05 (0.04, 0.06) for hsCRP, 0.13 (0.11, 0.15) for RDWPCR, 0.74 (0.64, 0.85) for MPVPCR, 0.11 (0.09, 0.13) for NLR and 0.57 (0.49, 0.66) for WBCNR in the fourth quartile compared with the first quartile, respectively.

CONCLUSIONS

Generally, the graded and inverse associations of serum 25(OH)D with hsCRP and four novel inflammatory markers (RDWPCR, MPVPCR, NLR and WBCNR) were observed. The present study provided further support for the anti-inflammatory effects of 25(OH)D.

Inflamm-ageing: How cytokines and nutrition shape the trajectory of ageing

Population ageing is increasing in prevalence in most developed countries. Ageing is the decline of functional properties at the cellular, tissue, and organ level. Biochemical changes that occur in all organisms that experience biological ageing are referred to as the "Hallmarks of ageing". Inflammation is a common denominator of the hallmarks of ageing, being mechanistically involved in most age-related health consequences. Inflamm-ageing refers to age-related changes in the inflammatory and immune systems which somehow drive the ageing process towards healthy or unhealthy ageing. Current evidences, support that, reversing the age-related pro-inflammatory status of inflamm-ageing, is able to modulate most hallmarks of ageing. Inflamm-ageing is associated with increased levels of pro-inflammatory molecules (e.g. cytokines, chemokines), ultimately producing a chronic low-grade inflammatory state typically observed in older individuals. It is commonly accepted that, the balance between pro- and anti-inflammatory cytokines/chemokines is one of the factors determining whether healthy or unhealthy ageing occurs. Malnutrition and nutritional imbalances, are highly prevalent in the elderly, playing a role in driving the balance of pro- and anti-inflammatory immunoactive molecules. In particular, malnutrition is a major risk factor for sarcopenia, a phenomenon characterized by loss of muscle mass, which is often referred to as the biological basis for frailty. Given the close relationship between malnutrition and sarcopenia, there is also evidence for a link between malnutrition and frailty. Indeed, changes in cytokine/chemokine levels in elderly patients with malnutrition were demonstrated. The demonstration that specific cytokines play a role in modulating appetite and nutrient sensing and taste reception, provided further evidence for the existence of a link between inflamm-ageing, nutrition and cytokines in shaping the trajectory of ageing. The present review will overview current evidence supporting the role of specific circulating cytokines and chemokines in the relationship between ageing, inflammation, and malnutrition.

Effect of weekly vitamin D supplementation on the severity of atopic dermatitis and type 2 immunity biomarkers in children: A randomized controlled trial

BACKGROUND

Vitamin D (VD) deficiency is common among patients with atopic dermatitis (AD) and often associated with severity. However, randomized trials of VD supplementation in AD have had equivocal results, and there is little information regarding the effect of VD supplementation on type 2 immunity in AD patients.

OBJECTIVES

To investigate the efficacy of VD supplementation to decrease severity of AD and to alter type 2 immunity biomarkers.

METHODS

We performed a randomized, double-blind, placebo-controlled trial. We randomly assigned 101 children with AD to weekly oral vitamin D3 (VD3) or placebo for 6 weeks. The primary outcome was the change in the Severity Scoring of AD (SCORAD).

RESULTS

Mean age of subjects was 6.3 ± 4.0 years, and baseline SCORAD was 32 ± 29. At baseline, 57% of children were VD deficient, with no difference between groups. Change in 25(OH)D was significantly greater with VD3 than placebo (+43.4 ± 34.5 nmol/L vs. +2.3 ± 21.2 nmol/L, p < 0.001). SCORAD change at 6 weeks was not different between VD and placebo (-5.3 ± 11.6 vs. -5.5 ± 9.9, p = 0.91). There were no significant between-group differences in change of eosinophil counts, total IgE, Staphylococcal enterotoxin specific IgE, CCL17, CCL22, CCL27, LL-37 or Staphylococcus aureus lesional skin colonization. Vitamin D receptor (VDR) gene single nucleotide polymorphisms FokI, ApaI and TaqI did not modify subjects' response to VD supplementation.

CONCLUSIONS

Among children with AD, weekly VD supplementation improved VD status but did not modify AD severity or type 2 immunity biomarkers compared to placebo (ClinicalTrials.gov NCT01996423).

Regulation of gut microbiota on immune cell ferroptosis: A novel insight for immunotherapy against tumor

Gut microbiota contributes to the homeostasis of immune system and is related to various diseases such as tumorigenesis. Ferroptosis, a new type of cell death, is also involved in the disease pathogenesis. Recent studies have found the correlations of gut microbiota mediated ferroptosis and immune cell death. Gut microbiota derived immunosuppressive metabolites, which can promote differentiation and function of immune cells, tend to inhibit ferroptosis through their receptors, whereas inflammatory metabolites from gut microbiota also affect the differentiation and function of immune cells and their ferroptosis. Thus, it is possible for gut microbiota to regulate immune cell ferroptosis. Indeed, gut microbiota metabolite receptor aryl hydrocarbon receptor (AhR) can affect ferroptosis of intestinal intraepithelial lymphocytes, leading to disease pathogenesis. Since immune cell ferroptosis in tumor microenvironment (TME) affects the occurrence and development of tumor, the modulation of gut microbiota in these cell ferroptosis might influence on the tumorigenesis, and also immunotherapy against tumors. Here we will summarize the recent advance of ferroptosis mediated by gut microbiota metabolites, which potentially acts as regulator(s) on immune cells in TME for therapy against tumor.

Advance in the mechanism and clinical research of myalgia in long COVID

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, mortality rates of coronavirus disease 2019 (COVID-19) have significantly decreased. However, a variable proportion of patients exhibit persistent prolonged symptoms of COVID-19 infection (long COVID). This virus primarily attacks respiratory system, but numerous individuals complain persistent skeletal muscle pain or worsening pre-existing muscle pain post COVID-19, which severely affects the quality of life and recovery. Currently, there is limited research on the skeletal muscle pain in long COVID. In this brief review, we review potential pathological mechanisms of skeletal muscle pain in long COVID, and summarize the various auxiliary examinations and treatments for skeletal muscle pain in long COVID. We consider abnormal activation of inflammatory response, myopathy, and neurological damages as pivotal pathological mechanisms of skeletal muscle pain in long COVID. A comprehensive examination is significantly important in order to work out effective treatment plans and relieve skeletal muscle pain. So far, rehabilitation interventions for myalgia in long COVID contain but are not limited to drug, nutraceutical therapy, gut microbiome-targeted therapy, interventional therapy and strength training. Our study provides a potential mechanism reference for clinical researches, highlighting the importance of comprehensive approach and management of skeletal muscle pain in long COVID. The relief of skeletal muscle pain will accelerate rehabilitation process, improve activities of daily living and enhance the quality of life, promoting individuals return to society with profound significance.

Cellular and Molecular Genetic Mechanisms of Lung Fibrosis Development and the Role of Vitamin D: A Review

Idiopathic pulmonary fibrosis remains a relevant problem of the healthcare system with an unfavorable prognosis for patients due to progressive fibrous remodeling of the pulmonary parenchyma. Starting with the damage of the epithelial lining of alveoli, pulmonary fibrosis is implemented through a cascade of complex mechanisms, the crucial of which is the TGF-β/SMAD-mediated pathway, involving various cell populations. Considering that a number of the available drugs (pirfenidone and nintedanib) have only limited effectiveness in slowing the progression of fibrosis, the search and justification of new approaches aimed at regulating the immune response, cellular aging processes, programmed cell death, and transdifferentiation of cell populations remains relevant. This literature review presents the key modern concepts concerning molecular genetics and cellular mechanisms of lung fibrosis development, based mainly on in vitro and in vivo studies in experimental models of bleomycin-induced pulmonary fibrosis, as well as the latest data on metabolic features, potential targets, and effects of vitamin D and its metabolites.

Active vitamin D analog and SARS-CoV-2 IgG after BNT162b2 vaccination in patients with hemodialysis

INTRODUCTION

Vaccination is the effective strategy for coronavirus disease 2019 (COVID-19). However, few studies have investigated the association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (Ig)G and vitamin D.

METHODS

This study aimed to investigate the association between SARS-CoV-2 IgG and active vitamin D analogs in hemodialysis patients. Blood samples were collected four times: before vaccination and 30, 60, and 90 days after vaccination, BNT162b2 (Pfizer©).

RESULTS

A total of 418 patients were enrolled. The mean age was 71.1 ± 12 years. Almost two thirds of the patients were prescribed active vitamin D analogs. The distribution of SARS-CoV-2 IgG before vaccination was 235 (93-454) AU/mL. After multiple regression analyses, active vitamin D analog use was found to be associated with higher SARS-CoV-2 IgG levels from prevaccination to 90 days postvaccination.

CONCLUSION

This study demonstrated an association between higher SARS-CoV-2 IgG and active vitamin D analog use in hemodialysis patients.

CLINICAL TRIAL REGISTRATION

The study information was registered in the UMIN-CTR (UMIN 000046906).

Vitamin D supplementation and calcium: Many-faced gods or nobody in fighting against Corona Virus Disease 2019

In December 2019, Corona Virus Disease 2019 (COVID-19) was first identified and designated as a pandemic in March 2020 due to rapid spread of the virus globally. At the beginning of the pandemic, only a few treatment options, mainly focused on supportive care and repurposing medications, were available. Due to its effects on immune system, vitamin D was a topic of interest during the pandemic, and researchers investigated its potential impact on COVID-19 outcomes. However, the results of studies about the impact of vitamin D on the disease are inconclusive. In the present narrative review, different roles of vitamin D regarding the COVID-19 have been discussed to show that vitamin D supplementation should be recommended carefully.

Vitamin D and allergic diseases

In recent years, the relationship between vitamin D and allergic diseases has received widespread attention. As a fat-soluble vitamin, vitamin D plays a crucial role in regulating the immune system and may influence the onset and progression of diseases such as atopic dermatitis, allergic rhinitis, and asthma. To understand the underlying mechanisms, we have summarized the current research on the association between vitamin D and allergic diseases. We also discuss the impact of vitamin D on the immune system and its role in the course of allergic diseases, particularly focusing on how vitamin D supplementation affects the treatment outcomes of these conditions. We aim to provide a theoretical basis and practical guidance for optimizing the management and treatment of allergic diseases by modulating vitamin D levels.

Vitamin D efficacy in type 1 and type 2 diabetes

It is well known that vitamin D has a profound effect on calcium and bone metabolism, but its influence on other organs (extraskeletal effect) has been proposed. Consistently, vitamin D deficiency is associated with an increased incidence of various diseases, including type 1 and type 2 diabetes, as reported by many observational studies. However, there has been no consensus on whether vitamin D deficiency is a causative factor in the incidence of diabetes mellitus. There have been no randomized controlled trials (RCTs) aimed at preventing the onset of type 1 diabetes with vitamin D intake. In addition, the results of RCTs evaluating the preventive effect of vitamin D supplementation on type 2 diabetes development have been inconsistent. The recent observational studies, randomized controlled trials, and meta-analyses are confirming that vitamin D or active vitamin D administration is effective in preventing the incident of type 1 and type 2 diabetes.

Spatial detection and consequences of nonrenal calcitriol production as assessed by targeted mass spectrometry imaging

The immune benefits of vitamin D3 supplementation beyond calcium and phosphate maintenance are highly clinically debated. Kidney expression of CYP27B1 is the source of endocrine, circulating 1,25(OH)2D3 (active form of vitamin D) that maintains serum calcium and phosphate. 1,25(OH)2D3 may also be made by the CYP27B1 enzyme in nonrenal cells, like immune cells, in a process driven by cellular availability of 25(OH)D3 and inflammation. Due to the endocrine nature of 1,25(OH)2D3 in circulation, it is difficult to discern between these 2 sources. We recently created a regulatory deletion model of Cyp27b1 (M1/M21-DIKO) where mice have normal inflammatory-regulated Cyp27b1 expression in nonrenal tissues (unlike global Cyp27b1-KO) but no expression within the kidney. Here, utilizing on-tissue chemical derivatization and matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI), we investigated the distribution of 1,25(OH)2D3 and 25(OH)D3 in the kidney, liver, spleen, and thymus. MALDI-MSI demonstrated increased 1,25(OH)2D3 in nonrenal tissues such as the spleen after vitamin D3 supplementation in M1/M21-DIKO mice. Additionally, from this, we found increased Il4 and decreased Tnfa in the spleen after vitamin D3 supplementation. Taken together, these data demonstrate nonrenal production of 1,25(OH)2D3 in vivo and provide a consequence of vitamin D3 supplementation and nonrenal 1,25(OH)2D3 production in cytokine changes.

The Roles of Gut Microbiota Metabolites in the Occurrence and Development of Colorectal Cancer: Multiple Insights for Potential Clinical Applications

Colorectal cancer (CRC) is one of the most common cancers worldwide. The occurrence and development of CRC are related to multiple risk factors such as gut microbiota. Indeed, gut microbiota plays an important role in the different phases of colorectal cancers (CRCs) from oncogenesis to metastasis. Some specific bacteria such as Fusobacterium nucleatum (F. nucleatum) associated with CRCs have been found. However, recently identified bile acid and tryptophan metabolites as well as short chain fatty acids (SCFAs), which are derived from gut microbiota, can also exert effects on the CRCs such as that SCFAs directly inhibit CRC growth. Importantly these metabolites also modulate immune responses to affect CRCs. They not only act as tumor inhibiting factor(s) but also promotor(s) in the occurrence, development, and metastasis of CRCs. While gut microbiota metabolites (GMMs) inhibit immunity against CRCs, some of them also improve immune responses to CRCs. Notably, GMMs also potentially affect the shaping of immune-privileged metastatic niches through direct roles or immune cells such as macrophages and myeloid-derived suppressive cells. These findings offer new insights for clinical application of gut microbiota in precise and personalized treatments of CRCs. Here, we will mainly discuss direct and indirect (via immune cells) effects of GMMs, especially SCFAs, bile acid and tryptophan metabolites on the occurrence, development and metastasis of CRCs.

Gender Differences in the Interplay between Vitamin D and Microbiota in Allergic and Autoimmune Diseases

The synergic role of vitamin D and the intestinal microbiota in the regulation of the immune system has been thoroughly described in the literature. Vitamin D deficiency and intestinal dysbiosis have shown a pathogenetic role in the development of numerous immune-mediated and allergic diseases. The physiological processes underlying aging and sex have proven to be capable of having a negative influence both on vitamin D values and the biodiversity of the microbiome. This leads to a global increase in levels of systemic inflammatory markers, with potential implications for all immune-mediated diseases and allergic conditions. Our review aims to collect and analyze the relationship between vitamin D and the intestinal microbiome with the immune system and the diseases associated with it, emphasizing the effect mediated by sexual hormones and aging.

Vitamin D constrains inflammation by modulating the expression of key genes on Chr17q12-21.1

Vitamin D possesses immunomodulatory functions and vitamin D deficiency has been associated with the rise in chronic inflammatory diseases, including asthma (Litonjua and Weiss, 2007). Vitamin D supplementation studies do not provide insight into the molecular genetic mechanisms of vitamin D-mediated immunoregulation. Here, we provide evidence for vitamin D regulation of two human chromosomal loci, Chr17q12-21.1 and Chr17q21.2, reliably associated with autoimmune and chronic inflammatory diseases. We demonstrate increased vitamin D receptor (Vdr) expression in mouse lung CD4+ Th2 cells, differential expression of Chr17q12-21.1 and Chr17q21.2 genes in Th2 cells based on vitamin D status and identify the IL-2/Stat5 pathway as a target of vitamin D signaling. Vitamin D deficiency caused severe lung inflammation after allergen challenge in mice that was prevented by long-term prenatal vitamin D supplementation. Mechanistically, vitamin D induced the expression of the Ikzf3-encoded protein Aiolos to suppress IL-2 signaling and ameliorate cytokine production in Th2 cells. These translational findings demonstrate mechanisms for the immune protective effect of vitamin D in allergic lung inflammation with a strong molecular genetic link to the regulation of both Chr17q12-21.1 and Chr17q21.2 genes and suggest further functional studies and interventional strategies for long-term prevention of asthma and other autoimmune disorders.

Vitamin D status in children with community acquired pneumonia and its association with severity: a hospital-based study

BACKGROUND

International and observational epidemiological studies provide evidence that vitamin D deficiency may confer increased risk of influenza and respiratory tract infection. This study was undertaken to evaluate the prevalence of vitamin D deficiency in pneumonia in children, and to assess its relationship with the severity.

METHODS

Study group included children aged between 2 months to 5 years of age admitted as inpatients who presented with clinical features of pneumonia as per WHO Classification. Detailed clinical assessment and physical examination was done at the time of admission and patients were enrolled and relevant findings were noted in prestructured proforma. Vitamin D levels <30 nmol/L (<12 ng/mL) were defined as deficient, 30-50 nmol/L (12-20 ng/mL) as insufficient, and >125 nmol/L (>50 ng/mL) as sufficient. Outcomes of the patients admitted were recorded in terms of duration of hospitalization, Intensive Care Unit (ICU) stay, oxygen requirement, antibiotic need and duration, need for upgradation of antibiotics, nebulization need with drugs used, ventilator need and other parameters. Statistical analysis was performed using statistical package for social sciences software (SPSS Inc., Chicago, IL, USA). A P value of <0.05 was considered statistically significant.

RESULTS

Out of 101 patients, 100% presented with fever, cough and fast breathing, 42.6% with grunting, 41 (40.5%) with noisy breathing, 5.7% with bluish discoloration, and 4.3% with apnea. Forty-one (40.5%) patients had crepitation, 53 (52.4%) patients had rhonchi, while 7 (6%) presented with bronchial breathing. Chest radiography features at admission helped to differentiate between presumed viral and presumed bacterial infection. Vitamin D deficient patients had significantly longer duration of hospital stay as compared to vitamin D sufficient group (P<0.001). The need for upgradation of antibiotics between the three groups were found to be significant (P<0.001). This showed that vitamin D deficiency is directly proportional to the need of upgradation of antibiotics. Bacterial pneumonia presents mostly as alveolar infiltrates and/or pleural effusion while viral pneumonia presents as interstitial infiltrates and/or hyperinflation. Cases with presumed bacterial pneumonia (based on X-ray, 38 out of 48, 79.1%) were more often vitamin D deficient as compared to case with presumed viral pneumonia (32 out of 52, 61.5%, P=0.05).

CONCLUSIONS

Vitamin D is widely prevalent in Indian children with pneumonia. Vitamin D deficient patients needed a longer duration of hospitalization, more upgradation of antibiotics, and PICU admissions; moreover, it had more CPAP requirement, longer duration of PICU stay and longer duration of CPAP requirements as compared to vitamin D sufficient group.

Vitamin D in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is characterized by the proliferation of malignant T cells in inflamed skin lesions. Mycosis fungoides (MF)-the most common variant of CTCL-often presents with skin lesions around the abdomen and buttocks ("bathing suit" distribution), i.e., in skin areas devoid of sun-induced vitamin D. For decades, sunlight and vitamin D have been connected to CTCL. Thus, vitamin D induces apoptosis and inhibits the expression of cytokines in malignant T cells. Furthermore, CTCL patients often display vitamin D deficiency, whereas phototherapy induces vitamin D and has beneficial effects in CTCL, suggesting that light and vitamin D have beneficial/protective effects in CTCL. Inversely, vitamin D promotes T helper 2 (Th2) cell specific cytokine production, regulatory T cells, tolerogenic dendritic cells, as well as the expression of immune checkpoint molecules, all of which may have disease-promoting effects by stimulating malignant T-cell proliferation and inhibiting anticancer immunity. Studies on vitamin D treatment in CTCL patients showed conflicting results. Some studies found positive effects, others negative effects, while the largest study showed no apparent clinical effect. Taken together, vitamin D may have both pro- and anticancer effects in CTCL. The balance between the opposing effects of vitamin D in CTCL is likely influenced by treatment and may change during the disease course. Therefore, it remains to be discovered whether and how the effect of vitamin D can be tilted toward an anticancer response in CTCL.

Immunomodulatory Effects of Vitamin D and Zinc on Viral Infection

Several nutrients are crucial in enhancing the immune system and preserving the structural integrity of bodily tissue barriers. Vitamin D (VD) and zinc (Zn) have received considerable interest due to their immunomodulatory properties and ability to enhance the body's immune defenses. Due to their antiviral, anti-inflammatory, antioxidative, and immunomodulatory properties, the two nutritional powerhouses VD and Zn are crucial for innate and adaptive immunity. As observed with COVID-19, deficiencies in these micronutrients impair immune responses, increasing susceptibility to viral infections and severe disease. Ensuring an adequate intake of VD and Zn emerges as a promising strategy for fortifying the immune system. Ongoing clinical trials are actively investigating their potential therapeutic advantages. Beyond the immediate context of the pandemic, these micronutrients offer valuable tools for enhancing immunity and overall well-being, especially in the face of future viral threats. This analysis emphasizes the enduring significance of VD and Zn as both treatment and preventive measures against potential viral challenges beyond the current health crisis. The overview delves into the immunomodulatory potential of VD and Zn in combating viral infections, with particular attention to their effects on animals. It provides a comprehensive summary of current research findings regarding their individual and synergistic impacts on immune function, underlining their potential in treating and preventing viral infections. Overall, this overview underscores the need for further research to understand how VD and Zn can modulate the immune response in combatting viral diseases in animals.

Vitamin D and immune system

The active metabolite of vitamin D 1,25(OH)2D is well known for its role in regulating calcium-phosphate homeostasis of the human body. However, the immunomodulating activity of 1,25(OH)2D has been known for many years. There are numerous reports correlating low vitamin D levels in blood serum with the onset of autoimmune diseases and with the severe course of acute infections. In this chapter, we address the role of 1,25(OH)2D in these diseases, and we discuss the possible mechanisms of action of 1,25(OH)2D in immune cells.

Recent Advances in Vitamin D3 Intervention to Eradicate Helicobacter pylori Infection

Helicobacter pylori (HP) infections affect approximately one-third of children worldwide. In China, the incidence of HP infection in children ranges from approximately 30% to 60%. In addition to damaging the gastrointestinal tract mucosa, HP infection in children can negatively affect their growth and development, hematology, respiratory and hepatobiliary system, skin, nutritional metabolism, and autoimmune system. However, the rate of HP eradication also fell considerably from the previous rate due to the presence of drug-resistant HP strains and the limited types of antibiotics that can be used in young patients. Vitamin D3 (VitD3) is a steroid hormone that can reduce inflammation in the stomach mucosa induced by HP and can alleviate and eradicate HP through a variety of pathways and mechanisms, including immune regulation and the stimulation of antimicrobial peptide (AMP) secretion and Ca2+ influx, to reestablish lysosomal acidification; thus, these results provide new strategies and ideas for the eradication of drug-resistant HP strains.

Gut microbiota: A double-edged sword in immune checkpoint blockade immunotherapy against tumors

Tumor cells can evade immune surveillance by expressing immune checkpoint molecule ligands, resulting in effective immune cell inactivation. Immune checkpoint blockades (ICBs) have dramatically improved survival of patients with multiple types of cancers. However, responses to ICB immunotherapy are heterogeneous with lower patient response rates. The advances have established that the gut microbiota can be as a promising target to overcome resistance to ICB immunotherapy. Furthermore, some bacterial species have shown to promote improved responses to ICBs. However, gut microbiota is critical in maintaining gut and systemic immune homeostasis. It not only promotes differentiation and function of immunosuppressive immune cells but also inhibits inflammatory cells via gut microbiota derived products such as short chain fatty acids (SCFAs), tryptophan (Trp) and bile acid (BA) metabolites, which play an important role in tumor immunity. Since the gut microbiota can either inhibit or enhance immune against tumor, it should be a double-edged sword in ICBs against tumor. In this review, we discuss the effects of gut microbiota on immune cells and also tumor cells, especially enhances of gut microbiota on ICB immunotherapy. These discussions can hopefully promote the development of ICB immunotherapy.

Immunomodulatory effect of vitamin D supplementation on Behçet's disease patients: effect on nitric oxide and Th17/Treg cytokines production

INTRODUCTION

In the last decade, an immuno-modulatory effect of vitamin D supplementation have emerged as a potential therapeutic approach for some inflammatory and autoimmune diseases. As previously reported, vitamin D deficiency was strongly linked to several diseases as Behçet's disease (BD). BD is a chronic systemic inflammatory disorder with autoimmunity, genetic and environmental factors involvement. The aim of our current study is to set up a new therapeutic strategy in BD, combining conventional therapy and vitamin D supplementation.

MATERIALS AND METHODS

Blood samples were collected from active and inactive BD patients and healthy controls (HC) to evaluate 25(OH) vitamin D levels using an electrochemiluminescence method. All deficient and insufficient vitamin D BD patients' were supplemented with vitamin D3 (CHOLECALCIFEROL, 200 000 UI/1 ml). In this context, NO, IL-17A and IL-10 levels were evaluated in patients and HC in vivo and ex vivo using Griess and ELISA methods respectively.

RESULTS

Before supplementation, we noted with interest that BD patients had vitamin D deficiency, associated with elevated in vivo and ex vivo NO and IL-17A levels compared to HC. Conversely, low IL-10 levels were observed in the same BD patients in comparison to HC. Interestingly, restored vitamin D status in supplemented BD patients was related to the decreased NO levels. In the same way, the IL-10/IL-17A ratio was improved.

CONCLUSIONS

Collectively, our data suggest that vitamin D supplementation in combination with conventional treatments has a beneficial effect and could constitute a good therapeutic candidate for alleviating inflammatory responses during Behçet disease.

Vitamin D Supplementation: Effect on Cytokine Profile in Multiple Sclerosis

Vitamin D is known for its role in modulating calcium and phosphate homeostasis and is implicated both in bone mineralization and immune system regulation. The immune-modulatory role of vitamin D and its impact on multiple sclerosis (MS) courses are still debated. The aim of this review was to check the effect of vitamin D supplementation on cytokine profile regulation in people with MS. A significant increase in serum concentrations of interleukin (IL)-10 and Transforming growth factor (TGF)-β1 after vitamin D supplementation was demonstrated in most studies, with some of them reporting a reduction in disability scores after vitamin D supplementation and an inverse correlation between IL-10 levels and disability. The effect of vitamin D on the serum levels of IL-17 and IL-6 was controversial; different results across studies could be explained by a variability in the treatment duration, route, and frequency of administration, as well as the dosage of vitamin D supplementation, responses to vitamin D treatment and the serum levels reached with supplementation, including the methods used for cytokine analysis and the different cell types investigated, the MS phenotype, the disease phase (active vs. non-active) and duration, and concomitant treatment with disease-modifying therapies. Nevertheless, the significant increase in the serum concentrations of IL-10 and TGF-β1, demonstrated in most studies, suggests an anti-inflammatory effect of vitamin D supplementation.

High-dose vitamin D3 supplementation shows no beneficial effects on white blood cell counts, acute phase reactants, or frequency of respiratory infections

BACKGROUND

Vitamin D has been suggested to influence the immune system, and vitamin D metabolites and the vitamin D receptor (VDR) are generated and expressed in white blood cells (WBC). Moreover, vitamin D status has been associated with incidence and prognosis of some respiratory tract infections (RTI). Therefore, we investigated the effect of vitamin D3 supplementation on WBC, acute phase reactants (APR), and the risk of developing RTIs.

METHODS

A double-blinded, randomized, placebo-controlled clinical trial of 307 infertile men with multiple secondary immunological endpoints. The vitamin D3 group (n = 151) initially received 300,000 IU (7,500 µg) cholecalciferol once - followed by 1,400 IU (35 µg) daily for 150 days. The placebo group (n = 156) did not receive active ingredients.

RESULTS

At baseline, stratification into clinically relevant groups of vitamin D status (< 25; 25-50; 50-75; >75 nmol/L), showed an inverse association with total leucocyte concentrations (7.0 vs. 6.0 vs. 6.0 vs. 5.5 (109/L); p = 0.007), lymphocytes (2.4 vs. 2.1 vs. 2.0 vs. 2.0 (109/L); p = 0.048), CRP (2.0 vs. 1.7 vs. 1.2 vs. 1.2 (mg/L); p = 0.037), and orosomucoid (0.82 vs. 0.77 vs. 0.76 vs. 0.70 (g/L); p = 0.015). After 150 days, no differences were detected in WBC counts or APRs between the vitamin D3 and the placebo group. However, vitamin D3 treated men had a higher prevalence of self-reported RTIs compared with the placebo group (55% vs. 39%; p = 0.005).

CONCLUSIONS

High-dose vitamin D3 supplementation did not alter WBCs or APRs, but a higher prevalence of respiratory infections was observed in the vitamin D3 group. Serum 25(OH)D3 was negatively correlated with most WBCs, indicating that vitamin D status may be linked with inflammation and WBC turnover, but not an important determinant of developing RTIs.

TRIAL REGISTRATION

NCT01304927 (ClinicalTrials.gov). Registered February 20, 2011.

Alterations in CD4+ T Cell Cytokines Profile in Female Patients with Hashimoto's Thyroiditis Following Vitamin D Supplementation: A Double-blind, Randomized Clinical Trial

BACKGROUND

Hashimoto's thyroiditis (HT) is an autoimmune disease characterized by the destruction of thyroid cells through immune processes involving T helper (Th)1 cytokines. This clinical trial investigates the impact of vitamin D supplementation on serum cytokine levels and gene expression in CD4+ T cells from HT patients, aiming to understand its effects on Th-1, Th-2, Th-17, and regulatory T (Treg) cell-associated factors.

METHODS

Female patients were randomly assigned in a double-blind design to either a vitamin D-supplemented group, which received cholecalciferol (1, 25(OH)2D3) at a dose of 50,000 IU, or the placebo group, which received a weekly placebo for a duration of three months. Serum cytokine levels were assessed using enzyme-linked immunosorbent assay (ELISA), while genes' expression levels were measured using real-time PCR.

RESULTS

Serum 25-hydroxyvitamin D and levels exhibited a significant increase following vitamin D supplementation, in comparison to the placebo group. Additionally, the vitamin D supplementation resulted in a significant elevation of serum calcium (Ca) levels compared to baseline. In the vitamin D group, there was a significant decrease in both serum levels and expression of the interleukin (IL)-17 gene when compared to baseline, although no statistical difference was observed between the placebo and vitamin D groups. The gene expression of transforming growth factor-beta (TGFβ) was significantly increased in the vitamin D group compared to baseline, with no significant difference between the two study groups. Vitamin D treatment had no effect on serum levels of interferon-gamma (IFNϒ) and IL-4. While the gene expression of IL-4 in the vitamin D group did not exhibit a statistically significant increase, the level of GATA3 transcription factor increased significantly when compared to the placebo group. The expression of IFNϒ and transcription factors, T-bet, RORc, and forkhead box protein 3 (FOXP3) in genes did not show significant changes following vitamin D supplementation.

CONCLUSION

The findings suggest that vitamin D supplementation may hold potential benefits for autoimmune diseases, such as HT. However, further longitudinal clinical trials are necessary to gain a more comprehensive understanding of the specific effects of vitamin D on HT.

The Potential Role of Vitamin D Supplementation in Cognitive Impairment Prevention

BACKGROUND

Vitamin D is implicated in many processes in the central nervous system (CNS), such as neurogenesis, neurotransmitter synthesis, synaptogenesis and protection against oxidative stress, thereby exerting a neuroprotective effect.

OBJECTIVE

In the present review, we aimed to evaluate the potential benefit(s) of vitamin D supplementation for CNS aging in different clinical contexts.

METHODS

We performed a literature search, looking for clinical trials and randomized clinical trials evaluating the effect of vitamin D supplementation on different endpoints related to cognitive outcomes.

RESULTS

Firstly, we identified 16 papers dealing with the impact of vitamin D supplementation on cognitive function in healthy subjects; the current literature suggests a real role for vitamin D supplementation in the prevention of cognitive decay in this clinical setting. Conversely, two papers suggest that vitamin D supplementation may be beneficial in patients with mild cognitive impairment (MCI). Finally, current data on vitamin D in Alzheimer's disease are contradictory.

CONCLUSION

Vitamin D supplementation may improve the cognitive outcomes of patients with MCI, whereas there is no evidence that it may prevent dementia or modulate the course of Alzheimer's disease.

Role of Vitamin D in Management of Diabetes and Unresolved Cardiovascular Diseases

BACKGROUND

Vitamin D deficiency is becoming a widely recognized global health issue. Serum values of 25-(OH) vitamin D (<20 ng/ml) are used to identify vitamin D deficiency. By prompting vascular endothelial cells to activate their nuclear receptor in cardio-myocytes, Vitamin D regulates obesity, Renin-angiotensin system (RAS), energy consumption, and pancreatic cell function. Vitamin D deficiency has been associated with diabetes, asthma, hyperlipidaemia, and pulmonary hypertension in humans.

METHODS

PubMed and Google Scholar databases were utilised to search the literature on vitamin D and related diseases.

RESULT

It is also linked to an elevated risk of death and heart disease. On the other hand, metaanalyses of vitamin D intervention and trials have found no substantial changes in insulin sensitivity, lipid markers, or blood pressure, which result in the association between deficiency of vitamin D and cardiovascular disease.

CONCLUSION

In this review, we present the most recent research on the effects of Vitamin D therapy on various cardiovascular diseases and diabetes, and explain the underlying mechanisms.

Effects of vitamin D supplementation on autoantibodies and thyroid function in patients with Hashimoto's thyroiditis: A systematic review and meta-analysis

BACKGROUND

Hashimoto's thyroiditis (HT) is the prevailing form of autoimmune thyroiditis and the leading cause of hypothyroidism in iodine-sufficient regions worldwide. This study aims to evaluate the efficacy of vitamin D supplementation on HT through a meta-analysis of randomized controlled trials (RCTs).

METHODS

The databases searched included PubMed, and others. We included RCTs that the treatment group received vitamin D, while the control group received either a placebo or no treatment. The studies measured the baseline and endpoint levels of 25-hydroxyvitamin D [25(OH)D], thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), anti-thyroid peroxidase antibody (TPO-Ab), and thyroglobulin antibody (TG-Ab). We performed a meta-analysis to calculate the standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

A total of 12 studies involving 862 individuals were included. Vitamin D supplementation has a significant impact on reducing the titers of TPO-Ab (SMD = -1.084, 95% CI = -1.624 to -0.545) and TG-Ab (SMD = -0.996, 95% CI = -1.579 to -0.413) in patients with HT, and it also improves thyroid function by decreasing TSH level (SMD = -0.167, 95% CI = -0.302 to 0.031) and increasing FT3 (SMD = 0.549, 95% CI = 0.077-1.020) and FT4 (SMD = 0.734, 95% CI = 0.184-1.285) levels. Active vitamin D (calcitriol) significantly reduces the titer of TPO-Ab compared to naive forms of vitamin D (vitamin D2 or D3); treatment durations > 12 weeks result in a more effective reduction of TPO-Ab levels and a more significant increase in FT4 and FT3 levels in patients with HT (meta-regression P < .05).

CONCLUSION

Vitamin D supplementation may have beneficial effects on HT patients by modulating immune responses and improving thyroid function.

Age-Dependent Effect of Calcitriol on Mouse Regulatory T and B Lymphocytes

The hormonally active vitamin D3 metabolite, calcitriol, functions as an important modulator of the immune system. We assumed that calcitriol exerts different effects on immune cells and cytokine production, depending on the age of the animal; therefore, we analyzed its effects on regulatory T lymphocytes and regulatory B lymphocytes in healthy young and old female C57Bl/6/Foxp3GFP mice. In the lymph nodes of young mice, calcitriol decreased the percentage of Tregs, including tTregs and pTregs, and the expression of GITR, CD103, and CD101; however, calcitriol increased the level of IL-35 in adipose tissue. In the case of aged mice, calcitriol decreased the percentages of tTregs and CD19+ cells in lymph nodes and the level of osteopontin in the plasma. Additionally, increases in the levels of IgG and the lowest levels of IFN-γ, IL-10, and IL-35 were observed in the adipose tissue of aged mice. This study showed that calcitriol treatment had different effects, mainly on Treg phenotypes and cytokine secretion, in young and old female mice; it seemed that calcitriol enhanced the immunosuppressive properties of the lymphatic organs and adipose tissue of healthy young mice but not of healthy aged mice, where the opposite effects were observed.

Seasonal Serum 25(OH) Vitamin D Level and Reproductive or Immune Markers in Reproductive-Aged Women with Infertility: A Cross-Sectional Observational Study in East Japan

Several studies have reported that vitamin D may modify human reproductive functions; however, the results are conflicting. We aimed to comprehensively evaluate serum vitamin D levels and examine the relationship between serum vitamin D levels and ovarian reserve markers, and immune markers of implantation, in reproductive-aged Japanese women with infertility.in reproductive-aged women with infertility. This cross-sectional, single-center study included reproductive-aged women who underwent preconception screening for fertility. Serum vitamin D levels and reproductive and immune markers were measured. Standard and advanced statistical techniques were used. We observed a statistically significant difference in the seasonal and monthly 25(OH) vitamin D levels; the 25(OH) vitamin D level during winter was the lowest among all seasons. However, there was no linear correlation between 25(OH) vitamin D levels and ovarian reserve markers, such as follicle-stimulating hormone and anti-Müllerian hormone, or the Th1/Th2 cell ratio, which is used as an implantation-related immunological marker. In this large-scale study, we evaluated the serum 25(OH) vitamin D concentration in reproductive-aged women with infertility in Japan; however, there was no association between reproductive function and vitamin D levels.

Insights into the role of vitamin D in targeting the culprits of non-alcoholic fatty liver disease

Vitamin D (VD) is a secosteroid hormone that is renowned for its crucial role in phospho-calcium homeostasis upon binding to the nuclear vitamin D receptor (VDR). Over and above, the pleiotropic immunomodulatory, anti-inflammatory, and metabolic roles VD plays in different disease settings started to surface in the past few decades. On the other hand, a growing body of evidence suggests a correlation between non-alcoholic fatty liver disease (NAFLD) and its progressive inflammatory form non-alcoholic steatohepatitis (NASH) with vitamin D deficiency (VDD) owing to the former's ingrained link with obesity and metabolic syndrome. Accordingly, a better understanding of the contribution of disrupted VDR signalling to NAFLD incidence and progression would provide further insights into its diagnosis, treatment modalities, and prognosis. This is especially significant as, hitherto, no drug for NAFLD has been approved. This review, therefore, sought to set forth the likely contribution of VDR signalling in NAFLD and how it might influence its multiple drivers.

Vitamin D and Cardiovascular Diseases: An Update

Vitamin D is a vital nutrient that plays a significant part in several physiological processes within the human body, including calcium metabolism, bone health, immune function, and cell growth and differentiation. It is obtained mainly through exposure to sunlight but can be acquired from certain foods and supplements as well. Vitamin D deficiency (VDD) could be the risk factor for cardiovascular diseases (CVDs), such as heart disease and stroke. In blood vitamin D low levels have been linked with an enhanced risk of developing CVDs. However, it is unclear whether vitamin D levels are the leading cause or consequence of these conditions. While some studies highlight that taking vitamin D supplements could decrease the risk of CVD; however, more research is required to better understand the association between vitamin D and cardiovascular health. In this review, we aimed to summarize the currently available evidence supporting the association between vitamin D and CVDs and anesthesia considerations.

In Vivo and In Vitro Evidence for an Interplay between the Glucocorticoid Receptor and the Vitamin D Receptor Signaling

Our previous work demonstrated that vitamin D (VitD) reduces experimental autoimmune encephalomyelitis (EAE) disease severity in wild-type (WT) but not in T cell-specific glucocorticoid (GC) receptor (GR)-deficient (GRlck) mice. This study aimed to investigate the interplay between the GR- and VitD receptor (VDR) signaling. In vivo, we confirmed the involvement of the GR in the VitD-induced effects in EAE using WT and GRlck mice. Furthermore, we observed that VitD-enhanced T cell apoptosis and T regulatory cell differentiation are diminished in vitro in CD3+ T cells of GRlck but not WT mice. Mechanistically, VitD does not appear to signal directly via the GR, as it does not bind to the GR, does not induce its nuclear translocation, and does not modulate the expression of two GR-induced genes. However, we observed that VitD enhances VDR protein expression in CD3+ T cells from WT but not GRlck mice in vitro, that the GR and the VDR spatially co-localize after VitD treatment, and that VitD does not modulate the expression of two VDR-induced genes in the absence of the GR. Our data suggest that a functional GR, specifically in T cells, is required for the VDR to signal appropriately to mediate the therapeutic effects of VitD.

Modifiable risk factors linked to the development of rheumatoid arthritis: evidence, immunological mechanisms and prevention

Rheumatoid Arthritis (RA) is a common autoimmune disease that targets the synovial joints leading to arthritis. Although the etiology of RA remains largely unknown, it is clear that numerous modifiable risk factors confer increased risk to developing RA. Of these risk factors, cigarette smoking, nutrition, obesity, occupational exposures and periodontal disease all incrementally increase RA risk. However, the precise immunological mechanisms by which these risk factors lead to RA are not well understood. Basic and translational studies have provided key insights into the relationship between inflammation, antibody production and the influence in other key cellular events such as T cell polarization in RA risk. Improving our general understanding of the mechanisms which lead to RA will help identify targets for prevention trials, which are underway in at-risk populations. Herein, we review the modifiable risk factors that are linked to RA development and describe immune mechanisms that may be involved. We highlight the few studies that have sought to understand if modification of these risk factors reduces RA risk. Finally, we speculate that modification of risk factors may be an appealing avenue for prevention for some at-risk individuals, specifically those who prefer lifestyle interventions due to safety and economic reasons.

Prolonged clinical remission of type 1 diabetes sustained by calcifediol and low-dose basal insulin: a case report

Herein, we describe an unusually prolonged duration (31 months) of the clinical remission phase in a 22-year-old Italian man with new-onset type 1 diabetes. Shortly after the disease diagnosis, the patient was treated with calcifediol (also known as 25-hydroxyvitamin D3 or calcidiol), coupled with low-dose basal insulin, to correct hypovitaminosis D and to exploit the anti-inflammatory and immunomodulatory properties of vitamin D. During the follow-up period, the patient retained a substantial residual β-cell function and remained within the clinical remission phase, as evidenced by an insulin dose-adjusted glycated hemoglobin value <9. At 24 months, we detected a peculiar immunoregulatory profile of peripheral blood cells, which may explain the prolonged duration of the clinical remission sustained by calcifediol as add-on treatment to insulin.

Vitamin D Status, Vitamin D Receptor Polymorphisms, and the Risk of Incident Rosacea: Insights from Mendelian Randomization and Cohort Study in the UK Biobank

BACKGROUND

Previous cross-sectional studies have failed to definitively establish a causal relationship between serum 25-hydroxyvitamin D (25OHD) concentrations and the onset of rosacea.

OBJECTIVE

To investigate the potential association between serum 25OHD levels, vitamin D receptor (VDR) polymorphisms, and the risk of developing incident rosacea.

METHODS

This cross-sectional population-based cohort study utilizing 370,209 individuals from the UK Biobank. Cox proportional hazard regression models and two-sample Mendelian randomization (MR) analyses were applied to explore the causative relationship between 25OHD and incident rosacea.

RESULTS

Our findings revealed that elevated levels of serum 25OHD were inversely correlated with the risk of incident rosacea. Specifically, compared to participants with 25OHD levels below 25 nmol/L, the multivariate-adjusted HR for incident rosacea was 0.81 (95% CI: 0.70, 0.94) in those with 25OHD levels exceeding 50 nmol/L. Further, in comparison to individuals with serum 25OHD less than 25 nmol/L and the rs731236 (TaqI) AA allele, those with serum 25OHD higher than 75 nmol/L and the TaqI GG allele had a multivariate-adjusted HR of 0.51 (95% CI 0.32 to 0.81) for developing rosacea. Results from the MR study supported a significant association, with each standard deviation increase in serum 25OHD concentrations correlating to a 23% reduced risk of rosacea (HR = 0.77, 95% CI: 0.63, 0.93).

CONCLUSIONS

The findings of this cohort study indicate an inverse association between increased concentrations of serum 25OHD and the risk of developing incident rosacea. While our results highlight the potential protective role of vitamin D, the definitive efficacy of vitamin D supplementation as a preventive strategy against rosacea requires further investigation.

VDR Gene Single Nucleotide Polymorphisms and Autoimmunity: A Narrative Review

The vitamin D/Vitamin D receptor (VDR) axis is crucial for human health as it regulates the expression of genes involved in different functions, including calcium homeostasis, energy metabolism, cell growth and differentiation, and immune responses. In particular, the vitamin D/VDR complex regulates genes of both innate and adaptive immunity. Autoimmune diseases are believed to arise from a genetic predisposition and the presence of triggers such as hormones and environmental factors. Among these, a role for Vitamin D and molecules correlated to its functions has been repeatedly suggested. Four single nucleotide polymorphisms (SNPs) of the VDR gene, ApaI, BsmI, TaqI, and FokI, in particular, have been associated with autoimmune disorders. The presence of particular VDR SNP alleles and genotypes, thus, was observed to modulate the likelihood of developing diverse autoimmune conditions, either increasing or reducing it. In this work, we will review the scientific literature suggesting a role for these different factors in the pathogenesis of autoimmune conditions and summarize evidence indicating a possible VDR SNP involvement in the onset of these diseases. A better understanding of the role of the molecular mechanisms linking Vitamin D/VDR and autoimmunity might be extremely useful in designing novel therapeutic avenues for these disorders.

Implications of vitamin D deficiency in systemic inflammation and cardiovascular health

Clinical, epidemiological, and molecular studies have sufficiently highlighted the vitality of vitamin D [25(OH)D and 1,25(OH)2D] in human health and wellbeing. Globally, vitamin D deficiency (VDD) has become a public health concern among all age groups. There is a very high prevalence of VDD per the estimates from several epidemiological studies on different ethnic populations. But, population-specific scales do not support these estimates to define VDD clinically and consistent genetic associations. However, clinical studies have shown the relevance of serum vitamin D screening and oral supplementation in improving health conditions, pointing toward a more prominent role of vitamin D in health and wellness. Routinely, the serum concentration of vitamin D is measured to determine the deficiency and is correlated with physiological conditions and clinical symptoms. Recent research points toward a more inclusive role of vitamin D in different disease pathologies and is not just limited to otherwise bone health and overall growth. VDD contributes to the natural history of systemic ailments, including cardiovascular and systemic immune diseases. Considering its significant impact on premature morbidity and mortality, there is a compelling need to comprehensively review and document the direct and indirect implications of VDD in immune system deregulation, systemic inflammatory conditions, and cardio-metabolism. The recommendations from this review call for furthering our research concerning vitamin D and its direct and indirect implications.

Genomically anchored vitamin D receptor mediates an abundance of bioprotective actions elicited by its 1,25-dihydroxyvitamin D hormonal ligand

The nuclear vitamin D receptor (VDR) mediates the actions of its physiologic 1,25-dihydroxyvitamin D3 (1,25D) ligand produced in kidney and at extrarenal sites during times of physiologic and cellular stress. The ligand-receptor complex transcriptionally controls genes encoding factors that regulate calcium and phosphate sensing/transport, bone remodeling, immune function, and nervous system maintenance. With the aid of parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), 1,25D/VDR primarily participates in an intricate network of feedback controls that govern extracellular calcium and phosphate concentrations, mainly influencing bone formation and mineralization, ectopic calcification, and indirectly supporting many fundamental roles of calcium. Beyond endocrine and intracrine effects, 1,25D/VDR signaling impacts multiple biochemical phenomena that potentially affect human health and disease, including autophagy, carcinogenesis, cell growth/differentiation, detoxification, metabolic homeostasis, and oxidative stress mitigation. Several health advantages conferred by 1,25D/VDR appear to be promulgated by induction of klotho, an anti-aging renal peptide hormone which functions as a co-receptor for FGF23 and, like 1,25D, regulates nrf2, foxo, mTOR and other cellular protective pathways. Among hundreds of genes for which expression is modulated by 1,25D/VDR either primarily or secondarily in a cell-specific manner, the resulting gene products (in addition to those expressed in the classic skeletal mineral regulatory tissues kidney, intestine, and bone), fall into multiple biochemical categories including apoptosis, cholesterol homeostasis, glycolysis, hypoxia, inflammation, p53 signaling, unfolded protein response and xenobiotic metabolism. Thus, 1,25D/VDR is a bone mineral control instrument that also signals the maintenance of multiple cellular processes in the face of environmental and genetic challenges.

Gut microbiota derived bile acid metabolites maintain the homeostasis of gut and systemic immunity

Bile acids (BAs) as cholesterol-derived molecules play an essential role in some physiological processes such as nutrient absorption, glucose homeostasis and regulation of energy expenditure. They are synthesized in the liver as primary BAs such as cholic acid (CA), chenodeoxycholic acid (CDCA) and conjugated forms. A variety of secondary BAs such as deoxycholic acid (DCA) and lithocholic acid (LCA) and their derivatives is synthesized in the intestine through the involvement of various microorganisms. In addition to essential physiological functions, BAs and their metabolites are also involved in the differentiation and functions of innate and adaptive immune cells such as macrophages (Macs), dendritic cells (DCs), myeloid derived suppressive cells (MDSCs), regulatory T cells (Treg), Breg cells, T helper (Th)17 cells, CD4 Th1 and Th2 cells, CD8 cells, B cells and NKT cells. Dysregulation of the BAs and their metabolites also affects development of some diseases such as inflammatory bowel diseases. We here summarize recent advances in how BAs and their metabolites maintain gut and systemic homeostasis, including the metabolism of the BAs and their derivatives, the role of BAs and their metabolites in the differentiation and function of immune cells, and the effects of BAs and their metabolites on immune-associated disorders.

Gene Polymorphisms and Biological Effects of Vitamin D Receptor on Nonalcoholic Fatty Liver Disease Development and Progression

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, with increasing prevalence worldwide. The genetic and molecular background of NAFLD pathogenesis is not yet clear. The vitamin D/vitamin D receptor (VDR) axis is significantly associated with the development and progression of NAFLD. Gene polymorphisms may influence the regulation of the VDR gene, although their biological significance remains to be elucidated. VDR gene polymorphisms are associated with the presence and severity of NAFLD, as they may influence the regulation of adipose tissue activity, fibrosis, and hepatocellular carcinoma (HCC) development. Vitamin D binds to the hepatic VDR to exert its biological functions, either by activating VDR transcriptional activity to regulate gene expression associated with inflammation and fibrosis or by inducing intracellular signal transduction through VDR-mediated activation of Ca²⁺ channels. VDR activity has protective and detrimental effects on hepatic steatosis, a characteristic feature of NAFLD. Vitamin D-VDR signaling may control the progression of NAFLD by regulating immune responses, lipotoxicity, and fibrogenesis. Elucidation of the genetic and molecular background of VDR in the pathophysiology of NAFLD will provide new therapeutic targets for this disease through the development of VDR agonists, which already showed promising results in vivo.

UV radiation and air pollution as drivers of major autoimmune conditions

Autoimmune diseases comprise a very heterogeneous group of disorders characterized by disruptive immune responses against self-antigens, chronic morbidity and increased mortality. The incidence and prevalence of major autoimmune conditions are particularly high in the western world, at northern latitudes, and in industrialized countries. This study will mainly focus on five major autoimmune conditions, namely type 1 diabetes, multiple sclerosis, inflammatory bowel diseases, rheumatoid arthritis, and autoimmune thyroid disorders. Epidemiological and experimental evidence suggests a protective role of sunlight exposure on the etiology of major autoimmune conditions mediated by the endogenous production of vitamin D and nitric oxide. A historical perspective shows how the rise of anthropogenic air pollutants is temporally associated with dramatic increases in incidence of these conditions. The scattering caused by ambient particulate matter and the presence of tropospheric ozone can reduce the endogenous production of vitamin D and nitric oxide, which are implicated in maintaining the immune homeostasis. Air pollutants have direct detrimental effects on the human body and are deemed responsible of an increasingly higher portion of the annual burden of human morbidity and mortality. Air pollution contributes in systemic inflammation, activates oxidative pathways, induces epigenetic alterations, and modulates the function and phenotype of dendritic cells, Tregs, and T-cells. In this review, we provide epidemiological and mechanistic insights regarding the role of UV-mediated effects in immunity and how anthropic-derived air pollution may affect major autoimmune conditions through direct and indirect mechanisms.

Immunologic, Anti-Inflammatory, and Anti-Muscle Damage Profile of Supplemented Vitamin D3 in Healthy Adults on Strenuous Endurance Exercise

Reportedly, strenuous endurance exercise can depress the immune system and induce inflammation and muscle damage. Therefore, this double-blinded, matched-pair study aimed to investigate the impact of vitamin D₃ supplementation on immune response (leukocyte, neutrophil, lymphocyte, CD4⁺, CD8⁺, CD19⁺, and CD56⁺ counts), inflammatory profile (TNF-α and IL-6), muscle damage (CK and LDH levels), as well as aerobic capacity after strenuous endurance exercise in 18 healthy men taking 5000 IU of vitamin D₃ (n = 9) or placebo (n = 9) daily for 4 weeks. Total and differential blood leukocyte counts, levels of cytokines, and muscle damage biomarkers were determined before, immediately after, and 2, 4, and 24 h after exercise. The IL-6, CK, and LDH levels were significantly lower in vitamin D₃ group at 2, 4, and 24 h post exercise (p < 0.05). Maximal and average heart rates during exercise were also significantly lower (p < 0.05). In the vitamin D₃ group, the CD4⁺/CD8⁺ ratio after 4 weeks of supplementation was only significantly lower at post-0 than at baseline and significantly higher at post-2 than at baseline and post-0 (all p < 0.05). Taken together, 5000 IU of daily vitamin D₃ supplementation for 4 weeks exhibited positive effects in terms of increased blood 25(OH)D levels, CD4⁺/CD8⁺ ratio (immune response), and aerobic capacity while inhibiting inflammatory cytokines and CK and LDH (muscle damage) in people performing strenuous endurance exercise.

Vitamin D in Diabetes: Uncovering the Sunshine Hormone's Role in Glucose Metabolism and Beyond

Over the last decades, epidemiology and functional studies have started to reveal a pivotal role of vitamin D in both type 1 and type 2 diabetes pathogenesis. Acting through the vitamin D receptor (VDR), vitamin D regulates insulin secretion in pancreatic islets and insulin sensitivity in multiple peripheral metabolic organs. In vitro studies and both T1D and T2D animal models showed that vitamin D can improve glucose homeostasis by enhancing insulin secretion, reducing inflammation, reducing autoimmunity, preserving beta cell mass, and sensitizing insulin action. Conversely, vitamin D deficiency has been shown relevant in increasing T1D and T2D incidence. While clinical trials testing the hypothesis that vitamin D improves glycemia in T2D have shown conflicting results, subgroup and meta-analyses support the idea that raising serum vitamin D levels may reduce the progression from prediabetes to T2D. In this review, we summarize current knowledge on the molecular mechanisms of vitamin D in insulin secretion, insulin sensitivity, and immunity, as well as the observational and interventional human studies investigating the use of vitamin D as a treatment for diabetes.

Relationship between Vitamin D and Immunity in Older People with COVID-19

Vitamin D is a group of lipophilic hormones with pleiotropic actions. It has been traditionally related to bone metabolism, although several studies in the last decade have suggested its role in sarcopenia, cardiovascular and neurological diseases, insulin-resistance and diabetes, malignancies, and autoimmune diseases and infections. In the pandemic era, by considering the response of the different branches of the immune system to SARS-CoV-2 infection, our aims are both to analyse, among the pleiotropic effects of vitamin D, how its strong multimodal modulatory effect on the immune system is able to affect the pathophysiology of COVID-19 disease and to emphasise a possible relationship between the well-known circannual fluctuations in blood levels of this hormone and the epidemiological trend of this infection, particularly in the elderly population. The biologically active form of vitamin D, or calcitriol, can influence both the innate and the adaptive arm of the immune response. Calcifediol levels have been found to be inversely correlated with upper respiratory tract infections in several studies, and this activity seems to be related to its role in the innate immunity. Cathelicidin is one of the main underlying mechanisms since this peptide increases the phagocytic and germicidal activity acting as chemoattractant for neutrophils and monocytes, and representing the first barrier in the respiratory epithelium to pathogenic invasion. Furthermore, vitamin D exerts a predominantly inhibitory action on the adaptive immune response, and it influences either cell-mediated or humoral immunity through suppression of B cells proliferation, immunoglobulins production or plasma cells differentiation. This role is played by promoting the shift from a type 1 to a type 2 immune response. In particular, the suppression of Th1 response is due to the inhibition of T cells proliferation, pro-inflammatory cytokines production (e.g., INF-γ, TNF-α, IL-2, IL-17) and macrophage activation. Finally, T cells also play a fundamental role in viral infectious diseases. CD4 T cells provide support to B cells antibodies production and coordinate the activity of the other immunological cells; moreover, CD8 T lymphocytes remove infected cells and reduce viral load. For all these reasons, calcifediol could have a protective role in the lung damage produced by COVID-19 by both modulating the sensitivity of tissue to angiotensin II and promoting overexpression of ACE-2. Promising results for the potential effectiveness of vitamin D supplementation in reducing the severity of COVID-19 disease was demonstrated in a pilot clinical trial of 76 hospitalised patients with SARS-CoV-2 infection where oral calcifediol administration reduced the need for ICU treatment. These interesting results need to be confirmed in larger studies with available information on vitamin D serum levels.

The role of vitamin D in periodontal health and disease

Vitamin D plays an essential role in calcium and bone metabolism, immune regulation and possesses profound anti-inflammatory effects. Evidence suggests that low serum vitamin D is associated with increased severity of periodontitis, a chronic inflammatory condition characterised by destruction of the supporting tissues surrounding the tooth, which has several shared risk factors with other chronic non-communicable diseases. The biological functions of vitamin D are mediated by its strong anti-microbial, anti-inflammatory, and host modulatory properties. Experimental periodontitis models involving targeted deletion of 1α-hydroxylase, the enzyme responsible for the conversion of inactive substrate to active 1,25(OH)₂ D₃ (calcitriol), showed augmented alveolar bone loss and gingival inflammation. Vitamin D receptor (VDR) gene polymorphisms have also been associated with increased severity of periodontitis. Thus, the involvement of vitamin D in the pathogenesis of periodontitis is biological plausible. Clinical studies have consistently demonstrated an inverse relationship between serum 25OHD₃ and periodontal disease inflammation. However, due to the paucity of well-designed longitudinal studies, there is less support for the impact of vitamin D status on periodontal disease progression and tooth loss. The evidence emphasises the importance of maintaining vitamin D sufficiency in supporting periodontal health. This review aims to first examine the biological mechanisms by which vitamin D might influence the pathogenesis of periodontal disease and second, discuss the clinical evidence which implicate the role of vitamin D in periodontal disease.

Two lineages of immune cells that differentially express the vitamin D receptor

Since 1983 it has been known that monocytes and activated T and B cells expressed the vitamin D receptor (VDR) and are therefore vitamin D targets. New data identified two lineages of immune cells that can be differentiated by the expression of the VDR. Monocytes, macrophages, neutrophils, and hematopoietic stem cells were mostly from VDR positive lineages. T cells, ILC1 and ILC3 were also largely VDR positive, which is consistent with the known effects of vitamin D as regulators of type-1 and type-3 immunity. Activation of the VDR negative T cells did not induce the expression of the VDR reporter, suggesting that perhaps only a subset of the T cells in the periphery express the VDR. When activated, the VDR negative T cells responded as if they were VDR knockout T cells in that they made more IFN-γ and proliferated faster than the VDR positive T cells. The ability of vitamin D to regulate immune function will depend on which cells express the VDR and a better understanding of the signals that regulate VDR expression in immune cells.

The relationship between serum cytokine profile and vitamin D in calves with neonatal diarrhea

It is important to know the characteristics of the immunological response in newborn calf diarrhea, which is often caused by bacterial, viral and protozoal pathogens. Cytokinesare proteins that serve as chemical messengers to regulate theinnate and adaptive arms of theimmune response. Changes in circulatory cytokine levels provide valuable information for understanding the pathophysiological process and monitoring disease progression and inflammation. Vitamin D has important immunomodulatory effects, which include enhancing the innate immune system and inhibiting adaptative immune responses. The objective of this study was to evaluate the relationship between serum cytokine profile and vitamin D level in neonatal calves with diarrhea. The study population was comprised of 40 neonatal calves, 32 of which had diarrhea and 8 of which were healthy calves. The calves with diarrhea were allocated to four groups according to bacterial (Escherichia coli), viral (Rotavirus, Coronavirus) and protozoal (Cryptosporidium parvum) etiologies. Circulatory vitamin D metabolites (25-hydroxyvitamin D, 1,25-dihydroxyvitamin D) and cytokines (TNF-α, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13 and IL-17) in the calves were determined. There was no statistically significant difference among the groups in 25-hydroxyvitamin D levels. 1,25-dihydroxyvitamin D levels were higher in Coronavirus and E. coli groups compared to the controls. Serum levels of all cytokines except for IL-13, were higher in E. coli group than those of the control group. As a result, differences in serum cytokines and vitamin D levels according to etiological factors in calf diarrhea indicate that vitamin D may play a role in the immune response in the disease.

Vitamin D Status and Psoriatic Arthritis: Association with the Risk for Sacroiliitis and Influence on the Retention Rate of Methotrexate Monotherapy and First Biological Drug Survival-A Retrospective Study

A growing body of evidence on the importance of vitamin D in immune modulation has increased the interest in its possible impact on the course of rheumatological diseases. The scope of our study is to assess if the presence of different statuses of vitamin D could interfere in the clinical subsets, in methotrexate monotherapy discontinuation, and biological drug (b-DMARDs) survival in psoriatic arthritis patients (PsA). We conducted a retrospective study on PsA patients and split them into three groups based on their vitamin D status: the group with 25(OH)D ≤ 20 ng/mL, the group with levels of 25(OH)D between 20 and 30 ng/mL, and the group with serum levels of 25(OH)D ≥ 30 ng/mL. All patients were required to fulfill the CASPAR criteria for psoriatic arthritis and to have the evaluation of vitamin D serum levels at baseline visit and at clinical follow-up visits. The exclusion criteria were ages less than 18 years old, the presence of HLA B27, and satisfaction of rheumatoid arthritis classification criteria (during the study time). Statistical significance was set at p ≤ 0.05. Furthermore, 570 patients with PsA were screened and 233 were recruited. A level of 25(OH)D ≤ 20 ng/mL was present in 39% of patients; levels of 25(OH)D between 20 and 30 ng/mL presented in 25% of patients; 65% of patients with sacroiliitis presented 25 (OH)D ≤ 20 ng/mL. Methotrexate monotherapy discontinuation for failure was higher in the group with 25 (OH)D ≤ 20 ng/mL (survival time: 92 ± 10.3 weeks vs. 141.9 ± 24.1 weeks vs. 160.1 ± 23.6 weeks; p = 0.02) with higher discontinuation risk (HR = 2.168, 95% CI 1.334, 3.522; p = 0.002) than those with 25(OH)D between 20 and 30 ng/mL and those with 25(OH)D ≥ 30 ng/mL. Significantly shorter survival of first b-DMARDs was assessed in the group with 25 (OH)D ≤ 20 ng/mL versus the other groups (133.6 ± 11 weeks vs. 204.8 ± 35.8 weeks vs. 298.9 ± 35.4; p = 0.028) (discontinuation risk 2.129, 95% CI 1.186, 3.821; p = 0.011). This study highlights significant differences in clinical presentation, in particular sacroiliac involvement and on drug survival (methotrexate and b-DMARDs) in PsA patients with vitamin D deficiency. Further prospective studies, including a larger sample of patients, are needed to validate these data and to assess if the supplementation of vitamin D could improve the b-DMARDs response in PsA patients.