A Narrative Role of Vitamin D and Its Receptor: With Current Evidence on the Gastric Tissues

Melatonin and vitamin D as potential synergistic adjuvants for cancer therapy (Review)

Significant advancements have been made in cancer therapy; however, limitations remain with some conventional approaches. Adjuvants are agents used alongside primary treatments to enhance their efficacy and the treatment outcomes of patients. Modern lifestyles contribute to deficiencies in melatonin and vitamin D. Limited sun exposure affects vitamin D synthesis, and artificial light at night suppresses melatonin production. Both melatonin and vitamin D possess anti‑inflammatory, immune‑boosting and anticancer properties, rendering them potential adjuvants of interest. Studies suggest melatonin and vitamin D supplementation may address antioxidant imbalances in lip, oral and pharyngeal cancers. Moreover, promising results from breast, head and neck, brain, and osteosarcoma research indicate potential for tumor growth inhibition, improved survival, and a better quality of life of patients with cancer. The radioprotective properties of melatonin and vitamin D are another exciting area of exploration, potentially enhancing radiotherapy effectiveness while reducing side effects. For its part, the sleep‑promoting effects of melatonin may indirectly benefit patients with cancer by influencing the immune system. Thus, the prevalence of vitamin D and melatonin deficiencies highlights the importance of supplementation, as lower levels can worsen side‑effects from cancer treatments. The present review explores the potential of combining melatonin and vitamin D as synergistic adjuvants for cancer therapy. These agents have shown promise individually in cancer prevention and treatment, and their combined effects warrant investigation. Therefore, large‑scale controlled trials are crucial to definitively determine the optimal dosage, safety and efficacy of this combination in improving the lives of patients with cancer.

The Effect of Vitamin D Supplementation Post COVID-19 Infection and Related Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D's role in COVID-19 management remains controversial. This meta-analysis aimed to evaluate the efficacy of vitamin D supplementation in patients with SARS-CoV-2 infection, focusing on mortality, intensive care unit (ICU) admissions, intubation rates, and hospital length of stay (LOS).

METHODS

A systematic review of PubMed/MEDLINE, Scopus, Cochrane, and Google Scholar databases was conducted. Randomized controlled trials (RCTs) and analytical studies investigating vitamin D supplementation in COVID-19 patients were included. The meta-analysis was performed using STATA MP 18.5, employing random-effect or fixed-effect models based on heterogeneity.

RESULTS

Twenty-nine studies (twenty-one RCTs, eight analytical) were analyzed. Vitamin D supplementation significantly reduced ICU admissions (OR = 0.55, 95% CI: 0.37 to 0.79) in RCTs and analytical studies (OR = 0.35, 95% CI: 0.18 to 0.66). Intubation rates were significantly reduced in RCTs (OR = 0.50, 95% CI: 0.27 to 0.92). Mortality reduction was significant in analytical studies (OR = 0.45, 95% CI: 0.24 to 0.86) but not in RCTs (OR = 0.80, 95% CI: 0.61 to 1.04). Subgroup analyses revealed more pronounced effects in older patients and severe COVID-19 cases. LOS showed a non-significant reduction (mean difference = -0.62 days, 95% CI: -1.41 to 0.18).

CONCLUSIONS

This meta-analysis suggests potential benefits of vitamin D supplementation in COVID-19 patients, particularly in reducing ICU admissions. However, the evidence varies across outcomes and patient subgroups. Discrepancies between RCTs and analytical studies highlight the need for further large-scale, well-designed trials accounting for baseline vitamin D status, standardized supplementation protocols, and patient characteristics to inform clinical guidelines for vitamin D use in COVID-19 management.

The Effectiveness of Vitamin D Intake in Improving Symptoms and Relapses of Multiple Sclerosis: A Systematic Review

There are disagreements over the effectiveness of vitamin D supplementation in treating multiple sclerosis (MS) patients' symptoms and reducing relapses. The goal of this systematic review is to assess the effect of vitamin D supplements on improving symptoms and relapses in MS patients. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted by searching eight databases: Embase, PubMed, Cochrane Library, MEDLINE, CINAHL, Web of Science, Scopus, and Google Scholar. The RoB 2 tool was used to evaluate the quality of the studies that were included in the analysis. From the 1,345 studies identified, 16 randomized controlled trials were selected. All studies reported that vitamin D administration significantly increased the mean serum 25(OH)D compared with the placebo group. Also, most included studies revealed a significant improvement in magnetic resonance imaging (MRI) brain lesion markers. However, most studies showed that being treated with vitamin D instead of placebo showed no significant effect on relapse rates, fatigue, Expanded Disability Status Scale (EDSS), serum neurofilament light chain (NfL), calcium, and cytokine levels, except for quality-of-life transforming growth factor beta (TGF-β). This systematic review shows that the effect of vitamin D supplements on improving symptoms and relapses during treatment in MS patients remains inconclusive.

Vitamin-D as a multifunctional molecule for overall well-being: An integrative review

Vitamin D is amongst the most important biomolecules to regularize and help in sustainable health, however, based on the studies, deficiency of this multifunctional vitamin is common. Vitamin D, besides playing a role in the form of vitamins, also acts as a multifunctional hormone (steroid). Vitamin D is synthesized inside the body through various steps starting from ultraviolet radiation exposure and comes from limited food sources, however, vitamin D-fortified food products are still among the major sources of vitamin D. Current review, focused on how vitamin D acts as a multifunctional molecule by effecting different functions in the body in normal or specific conditions and how it is important in fortification and how it can be managed from the available literature till date. During the Covid pandemic, people were aware of vitamin D and took supplementation, fortified foods, and sat under sunlight. As COVID prevalence decreases, people start forgetting about vitamin D. Vitamin D is very crucial for overall well-being as it has protective effects against a broad range of diseases as it can reduce inflammation, cancer cell growth and helps in controlling infection, increase metabolism, muscle, and bone strength, neurotransmitter expression, etc. Therefore, the present review is to provoke the population, and fulfillment of the vitamin D recommended dietary allowance daily must be confirmed.

The role of vitamin D in amelioration of oral lichen planus and its effect on salivary and tissue IFN-γ level: a randomized clinical trial

BACKGROUND AND OBJECTIVES

Oral lichen planus (OLP) is a common, prevalent, immune-mediated, inflammatory disease affecting both the skin and oral mucosa and is considered one of the potentially malignant diseases. Since OLP is regarded as an immunologically mediated disease, some studies suggest the use of vitamin D (VD) for its management as it exhibits immune-modulatory, anti-inflammatory, and antimicrobial properties, as well as anti-proliferative, pro-differentiative, and anti-angiogenic effects. VD has demonstrated a suppressive effect on TH1 pro-inflammatory cytokines, including IFN-γ while augmenting the secretion of anti-inflammatory cytokines. At the same time, VD deficiency is a prevalent public issue. Therefore, the present study aimed to investigate the role of VD as an adjunct to steroids in the management of VD-deficient OLP patients as well as its inhibitory effect on IFN-γ through measurement of salivary and tissue IFN-γ levels in OLP patients.

METHODS

A total of 40 patients with ulcerative or erythematous OLP, diagnosed according to the World Health Organization's (WHO) modified criteria for OLP, were randomly allocated into one of the two study groups to receive either systemic steroids in addition to VD supplements (Group A) or systemic steroids only (Group B). Blood samples were collected for the measurement of serum VD level (SVDL) using the enzyme-linked immunosorbent assay (ELISA) to involve only patients with VD deficiency or insufficiency (≤ 30 ng/ml). Clinical evaluation of the lesion involved objective signs and subjective symptoms. Also, changes in salivary and tissue INF-γ levels (in pg/mL and pg/mg, respectively) were determined using the ELISA technique. All parameters were measured at baseline and after 4 weeks of treatment. The clinical pharmacy team devised a checklist to record all team interventions. The interventions were categorized into six domains, including drug interactions and/or adverse reactions, medication dose issues, drug selection issues, support with medication history, patient-related concerns, and suggestions for dental medication.

RESULTS

After one month of treatment, a significantly greater number of patients in group A showed complete pain relief and resolution of clinical lesions, as well as a greater number of patients showing a reduction in the clinical severity of lesions than in group B (P = 0.005). Also, there was a statistically significant reduction in average VAS pain scores and clinical scores in group A compared to group B after 1 month of treatment (P = 0.001 and 0.002, respectively). Furthermore, there was a statistically significant greater reduction in salivary and tissue IFN-γ levels in group A than in group B (P ≤ 0.001 and 0.029, respectively) after 1 month of treatment.

CONCLUSION

Current evidence suggests a significant preventive and therapeutic role for VD as an adjunct to standard therapies indicated for OLP lesions. These protective and therapeutic functions are achieved through the suppressive effect of VD on pro-inflammatory cytokines, particularly IFN-γ. Also, salivary IFN-γ appears to be a valuable prognostic marker for monitoring the progression of OLP. In addition, the inter-professional collaboration between dentists and clinical pharmacists helped to deliver complete, patient-centered primary care and ensured the quality of the medications included in patient kits, thus improving patient treatment and management. Nevertheless, further studies with larger sample sizes, longer follow-ups, and standardized designs may still be needed.

Structural diversification of vitamin D using microbial biotransformations

Vitamin D deficiencies are linked to multiple human diseases. Optimizing its synthesis, physicochemical properties, and delivery systems while minimizing side effects is of clinical relevance and is of great medical and industrial interest. Biotechnological techniques may render new modified forms of vitamin D that may exhibit improved absorption, stability, or targeted physiological effects. Novel modified vitamin D derivatives hold promise for developing future therapeutic approaches and addressing specific health concerns related to vitamin D deficiency or impaired metabolism, such as avoiding hypercalcemic effects. Identifying and engineering key enzymes and biosynthetic pathways involved, as well as developing efficient cultures, are therefore of outmost importance and subject of intense research. Moreover, we elaborate on the critical role that microbial bioconversions might play in the a la carte design, synthesis, and production of novel, more efficient, and safer forms of vitamin D and its analogs. In summary, the novelty of this work resides in the detailed description of the physiological, medical, biochemical, and epidemiological aspects of vitamin D supplementation and the steps towards the enhanced and simplified industrial production of this family of bioactives relying on microbial enzymes. KEY POINTS: • Liver or kidney pathologies may hamper vitamin D biosynthesis • Actinomycetes are able to carry out 1α- or 25-hydroxylation on vitamin D precursors.

The photo-protective role of vitamin D in the microalga Emiliania huxleyi

An essential interaction between sunlight and eukaryotes involves vitamin D production through exposure to ultraviolet (UV) radiation. While extensively studied in vertebrates, the role of vitamin D in non-animal eukaryotes like microalgae remains unclear. Here, we investigate the potential involvement of vitamin D in the UV-triggered response of Emiliania huxleyi, a microalga inhabiting shallow ocean depths that are exposed to UV. Our results show that E. huxleyi produces vitamin D2 and D3 in response to UV. We further demonstrate that E. huxleyi responds to external administration of vitamin D at the transcriptional level, regulating protective mechanisms that are also responsive to UV. Our data reveal that vitamin D addition enhances algal photosynthetic performance while reducing harmful reactive oxygen species buildup. This study contributes to understanding the function of vitamin D in E. huxleyi and its role in non-animal eukaryotes, as well as its potential importance in marine ecosystems.

Exploring the Role of Vitamin D, Vitamin D-Dependent Proteins, and Vitamin D Receptor Gene Variation in Lung Cancer Risk

Lung cancer has an unfavorable prognosis with a rate of low overall survival, caused by the difficulty of diagnosis in the early stages and resistance to therapy. In recent years, there have been new therapies that use specific molecular targets and are effective in increasing the survival chances of advanced cancer. Therefore, it is necessary to find more specific biomarkers that can identify early changes in carcinogenesis and allow the earliest possible treatment. Vitamin D (VD) plays an important role in immunity and carcinogenesis. Furthermore, the vitamin D receptor (VDR) regulates the expression of various genes involved in the physiological functions of the human organism. The genes encoding the VDR are extremely polymorphic and vary greatly between human populations. To date, there are significant associations between VDR polymorphism and several types of cancer, but the data on the involvement of VDR polymorphism in lung cancer are still conflicting. Therefore, in this review, our aim was to investigate the relationship between VDR single-nucleotide polymorphisms in humans and the degree of risk for developing lung cancer. The studies showcased different gene polymorphisms to be associated with an increased risk of lung cancer: TaqI, ApaI, BsmI, FokI, and Cdx2. In addition, there is a strong positive correlation between VD deficiency and lung cancer development. Still, due to a lack of awareness, the assessment of VD status and VDR polymorphism is rarely considered for the prediction of lung cancer evolution and their clinical applicability, despite the fact that studies have shown the highest risk for lung cancer given by TaqI gene polymorphisms and that VDR polymorphisms are associated with more aggressive cancer evolution.

Impact of vitamin D supplementation as COVID-19 vaccine adjuvant on sperm parameters and sex hormones in men with idiopathic infertility: Two separate pre-post studies

OBJECTIVE

Vitamin D deficiency is a major problem for human health worldwide. The mechanisms of vitamin D in the male reproductive system are unknown. After coronavirus disease 2019 (COVID-19) vaccines were developed, doubts were raised about their possible effects on male fertility. Based on vitamin D's function in the immune system, its potential role as an adjuvant for COVID-19 vaccines is intriguing. The aims of this study were to assess the effects of vitamin D first on sperm parameters and sex hormones, and then as an immune adjuvant on sperm parameters and sex hormones after study participants had received their second doses of COVID-19 vaccines.

METHODS

Phase 1 (before the COVID-19 pandemic) included 72 men with idiopathic infertility, and phase 2 had 64 participants who received two doses of COVID-19 vaccines. Both groups were instructed to take 50,000 IU of vitamin D twice monthly for 3 months. Sperm parameters and sex hormones were assessed pre- and post-supplementation.

RESULTS

Regular vitamin D intake for 3 months significantly increased the participants' vitamin D levels (p=0.0001). Both phases showed a positive correlation between vitamin D intake and sperm parameters. Vaccination had no negative effects on sperm parameters and sex hormones. Vitamin D was associated with follicle-stimulating hormone (p=0.02) and testosterone (p=0.0001) in phase 2 after treatment.

CONCLUSION

Our results support vitamin D supplementation as an immune adjunct to COVID-19 vaccination for improving sperm parameters and hormone levels. COVID-19 vaccination is not harmful for male fertility potential, and vitamin D is an effective factor for male fertility.

A hypothesis: MiRNA-124 mediated regulation of sirtuin 1 and vitamin D receptor gene expression accelerates aging

Objectives

Specific miRNAs are evident to be overexpressed with age, lifestyle, and environmental changes. Previous studies reported miR-124 overexpression in different scenarios in aged skin, age-related cognitive impairment, ischemic heart disease, muscle atrophy, and fractures. Thus miR-124 was considered to be a reliable miRNA target to establish a hypothesis on aging epigenome. Parallelly the hypothesis focuses on the expression of SIRT1 and VDR genes as a target for this specific miRNA expression as these genes were believed to be related to aging. This study aims to derive facts and evidence from past studies on aging. The objective was to establish a hypothetical linkage between miR-124 with age-related genes like SIRT1 and VDR.

Methods

An in silico search was performed in the TargetScan and miRbase databases to analyze the aging-associated miRNAs and their gene targets, the Python seaborn library was used, and the results were represented in terms of a bar plot.

Results

Based on an in silico analysis and studies available in the literature, we identified that miR-124-3p.1 and miR-124-3p.2 targets 3' UTR of VDR and SIRT1 genes, and hence thereby indicates that the miR-124 can regulate the expression of these genes. Further, few in vitro research studies have observed that miR-124 overexpression leads to the downregulation of VDR and SIRT1 gene expression. These results indicate that the suppression of these target genes accelerates early aging and age-related disorders.

Conclusions

Overall, this study hypothesizes that the overexpression of miR-124 diminishes the expression of VDR and SIRT1 genes, and thereby advances the process of aging, resulting in the development of age-associated complications.

Effects of dietary nitrogen and/or phosphorus reduction on mineral homeostasis and regulatory mechanisms in young goats

Introduction

The reduction of nitrogen (N) and phosphorus (P) in ruminant feed is desirable due to costs and negative environmental impact. Ruminants are able to utilize N and P through endogenous recycling, particularly in times of scarcity. When N and/or P were reduced, changes in mineral homeostasis associated with modulation of renal calcitriol metabolism occurred. The aim of this study was to investigate the potential effects of dietary N- and/or P-reduction on the regulatory mechanisms of mineral transport in the kidney and its hormonal regulation in young goats.

Results

During N-reduction, calcium (Ca) and magnesium (Mg) concentrations in blood decreased, accompanied by a lower protein expression of cytochrome P450 family 27 subfamily B member 1 (CYP27B1) (p = 0.016). The P-reduced fed goats had low blood phosphate concentrations with simultaneously high Ca and Mg levels. The insulin-like growth factor 1 concentrations decreased significantly with P-reduction. Furthermore, gene expression of CYP27B1 (p < 0.001) and both gene (p = 0.025) and protein (p = 0.016) expression of the fibroblast growth factor receptor 1c isoform in the kidney were also significantly reduced during a P-reduced diet. ERK1/2 activation exhibited a trend toward reduction in P-reduced animals. Interestingly, calcitriol concentrations remained unaffected by either restriction individually, but interacted significantly with N and P (p = 0.014). Additionally, fibroblast growth factor 23 mRNA expression in bone decreased significantly with P-restriction (p < 0.001).

Discussion

These results shed light on the complex metabolic and regulatory responses of mineral transport of young goats to dietary N and P restriction.

Unraveling the complex interplay between obesity and vitamin D metabolism

Vitamin D deficiency and obesity are a worldwide health issue. Obesity refers to the accumulation of excessive fats in the body which could lead to the development of diseases. Obese people have low vitamin D levels for several reasons including larger volume of distribution, vitamin D tightly bound in fatty tissues, reduced absorption, and diets with low vitamin D. Accurately measuring vitamin D metabolites is challenging. The Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method was developed and validated for the analysis of vitamin D metabolites in the serum. Blood samples were collected from 452 subjects which consisted of baseline (vitamin D deficient obese subjects), follow-up (supplemented obese subjects), and healthy volunteers. The vitamin D metabolites were separated adequately by the developed UHPLC-MS/MS method. Moreover, the validation criteria for the method were within an acceptable range. The baseline, follow-up and even healthy volunteers were deficient in 25OHD3 and 25OHD2. The baseline and healthy subjects had comparable concentration of vitamin D2 and D3. However, healthy subjects had a higher concentration of 25OHD and its epimer compared to the baseline subjects. The vitamin D3 was increased significantly in the follow- up subjects; therefore, the 25OHD3 was increased significantly compared to the baseline as well; however, the increase was insufficient to achieve the optimal range. The UHPLC-MS/MS method test was applied successfully on estimation of vitamin D metabolites in subjects. This study indicates the significance of taking into account the metabolic and storage effects when evaluating the vitamin D status in obese subjects.

Identification of trans-genus biomarkers for early diagnosis of intestinal schistosomiasis and progression of gut pathology in a mouse model using metabolomics

Schistosomiasis is one of the most devastating human diseases worldwide. The disease is caused by six species of Schistosoma blood fluke; five of which cause intestinal granulomatous inflammation and bleeding. The current diagnostic method is inaccurate and delayed, hence, biomarker identification using metabolomics has been applied. However, previous studies only investigated infection caused by one Schistosoma spp., leaving a gap in the use of biomarkers for other species. No study focused on understanding the progression of intestinal disease. Therefore, we aimed to identify early gut biomarkers of infection with three Schistosoma spp. and progression of intestinal pathology. We infected 3 groups of mice, 3 mice each, with Schistosoma mansoni, Schistosoma japonicum or Schistosoma mekongi and collected their feces before and 1, 2, 4 and 8 weeks after infection. Metabolites in feces were extracted and identified using mass spectrometer-based metabolomics. Metabolites were annotated and analyzed with XCMS bioinformatics tool and Metaboanalyst platform. From >36,000 features in all conditions, multivariate analysis found a distinct pattern at each time point for all species. Pathway analysis reported alteration of several lipid metabolism pathways as infection progressed. Disturbance of the glycosaminoglycan degradation pathway was found with the presence of parasite eggs, indicating involvement of this pathway in disease progression. Biomarkers were discovered using a combination of variable importance for projection score cut-off and receiver operating characteristic curve analysis. Five molecules met our criteria and were present in all three species: 25-hydroxyvitamin D2, 1α-hydroxy-2β-(3-hydroxypropoxy) vitamin D3, Ganoderic acid Md, unidentified feature with m/z 455.3483, and unidentified feature with m/z 456.3516. These molecules were proposed as trans-genus biomarkers of early schistosomiasis. Our findings provide evidence for disease progression in intestinal schistosomiasis and potential biomarkers, which could be beneficial for early detection of this disease.

Vitamin D supplementation in a post-pandemic era: A narrative review

Vitamin D is a fat-soluble molecule referring to the different isoforms, ergocalciferol (D2) and cholecalciferol (D3). Its physiological functions include increasing calcium serum concentrations. 25-hydroxyvitamin D3 (25(OH)D) (Calcifediol), a non-active, circulating instant precursor is seen as a pre-hormone. Studies have shown that a deficiency in calcifediol is related to chronic conditions such as cardiovascular, musculoskeletal, immune system, neurological, and anti-neoplastic functions. Vitamin D supplementation has shown its benefit as prophylaxis and treatment during the coronavirus disease 2019 (COVID-19) pandemic and an increase in the prescribing of vitamin D supplementation has been observed. The intention of this review article is to provide guidance on the recommended dosage regimen as a prophylactic measure during COVID-19 and its use as a supplement in general. From this review article, it is clear that vitamin D has an important role to play not only in COVID-19 but also in various other health aspects of the human body.Contribution: This review article highlighted the role of vitamin D in managing vitamin D deficiency and its role as a supplement in the management of respiratory tract infections, especially COVID-19. This overview can assist physicians in optimising healthcare by optimised dosing recommendations and indications.

In vitro regulation of fibroblast growth factor 23 by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D synthesized by osteocyte-like MC3T3-E1 cells

Fibroblast growth factor 23 (FGF23) is produced and secreted by osteocytes and is essential for maintaining phosphate homeostasis. One of the main regulators of FGF23, 1,25-dihydroxyvitamin D (1,25(OH)2D3), is primarily synthesized in the kidney from 25-hydroxyvitamin D (25(OH)D) by 1α-hydroxylase (encoded by CYP27B1). Hitherto, it is unclear whether osteocytes can convert 25(OH)D and thereby allow for 1,25(OH)2D3 to induce FGF23 production and secretion locally. Here, we differentiated MC3T3-E1 cells toward osteocyte-like cells expressing and secreting FGF23. Treatment with 10-6 M 25(OH)D resulted in conversion of 25(OH)D to 150 pmol/L 1,25(OH)2D3 and increased FGF23 expression and secretion, but the converted amount of 1,25(OH)2D3 was insufficient to trigger an FGF23 response, so the effect on FGF23 was most likely directly caused by 25(OH)D. Interestingly, combining phosphate with 25(OH)D resulted in a synergistic increase in FGF23 expression and secretion, likely due to activation of additional signaling pathways by phosphate. Blockage of the vitamin D receptor (VDR) only partially abolished the effects of 25(OH)D or 25(OH)D combined with phosphate on Fgf23, while completely inhibiting the upregulation of cytochrome P450 family 24 subfamily A member 1 (Cyp24a1), encoding for 24-hydroxylase. RNA sequencing and in silico analyses showed that this could potentially be mediated by the nuclear receptors Retinoic Acid Receptor β (RARB) and Estrogen Receptor 2 (ESR2). Taken together, we demonstrate that osteocytes are able to convert 25(OH)D to 1,25(OH)2D3, but this is insufficient for FGF23 activation, implicating a direct effect of 25(OH)D in the regulation of FGF23, which occurs at least partially independent from its cognate VDR. Moreover, phosphate and 25(OH)D synergistically increase expression and secretion of FGF23, which warrants investigating consequences in patients receiving a combination of vitamin D analogues and phosphate supplements. These observations help us to further understand the complex relations between phosphate, vitamin D, and FGF23.

1,25-Dihydroxyvitamin D3 regulates furin-mediated FGF23 cleavage

Intact fibroblast growth factor 23 (iFGF23) is a phosphaturic hormone that is cleaved by furin into N-terminal and C-terminal fragments. Several studies have implicated vitamin D in regulating furin in infections. Thus, we investigated the effect of 1,25-dihydroxyvitamin D3 [1,25(OH)2D] and the vitamin D receptor (VDR) on furin-mediated iFGF23 cleavage. Mice lacking VDR (Vdr-/-) had a 25-fold increase in iFGF23 cleavage, with increased furin levels and activity compared with wild-type (WT) littermates. Inhibition of furin activity blocked the increase in iFGF23 cleavage in Vdr-/- animals and in a Vdr-knockdown osteocyte OCY454 cell line. Chromatin immunoprecipitation revealed VDR binding to DNA upstream of the Furin gene, with more transcription in the absence of VDR. In WT mice, furin inhibition reduced iFGF23 cleavage, increased iFGF23, and reduced serum phosphate levels. Similarly, 1,25(OH)2D reduced furin activity, decreased iFGF23 cleavage, and increased total FGF23. In a post hoc analysis of a randomized clinical trial, we found that ergocalciferol treatment, which increased serum 1,25(OH)2D, significantly decreased serum furin activity and iFGF23 cleavage, compared with placebo. Thus, 1,25(OH)2D inhibits iFGF23 cleavage via VDR-mediated suppression of Furin expression, thereby providing a mechanism by which vitamin D can augment phosphaturic iFGF23 levels.

Vitamin D: An Overview of Gene Regulation, Ranging from Metabolism to Genomic Effects

Vitamin D is a pro-hormone characterized by an intricate metabolism and regulation. It is well known for its role in calcium and phosphate metabolism, and in bone health. However, several studies have assessed a huge number of extra-skeletal functions, ranging from cell proliferation in some oncogenic pathways to antioxidant and immunomodulatory functions. Vitamin D exerts its role by binding to VDRs (vitamin D receptors), which are located in many different tissues. Moreover, VDRs are able to bind hundreds of genomic loci, modulating the expression of various primary target genes. Interestingly, plenty of gene polymorphisms regarding VDRs are described, each one carrying a potential influence against gene expression, with relapses in several chronic diseases and metabolic complications. In this review, we provide an overview of the genetic aspects of vitamin D and VDR, emphasizing the gene regulation of vitamin D, and the genetic modulation of VDR target genes. In addition, we briefly summarize the rare genetic disease linked to vitamin D metabolism.

Immunomodulatory Effects of Vitamin D in Respiratory Tract Infections and COVID-19 in Children

Acute respiratory tract infections (ARTIs) are one of the main reasons that the pediatric population goes to the doctor. The connection between ARTI and vitamin D (VD) is currently debated by the medical community, and so far, there has been little agreement with regard to the ideal level of 25(OH)D concentration that would provide protection for the respiratory tract, or the effectiveness of its administration in the treatment of respiratory infections. The purpose of this literature review was to bring attention to the immunomodulatory and antiviral function of vitamin D and its relation to the respiratory system by examining the main ARTIs, including SARS-CoV-2. The latter has affected the pediatric population in different ways, from asymptomatic patients to severe forms with multisystem inflammatory syndrome in children (MIS-C). Although there are not much clinical data on the SARS-CoV-2 disease in the pediatric population worldwide, we tried to find out whether there is a connection between the severity of this disease, other ARTIs, and vitamin D supplementation. We also aimed to find out if 25OHD deficiency had an adverse effect on the evolution of the disease and the recovery period in the case of younger patients affected by COVID-19. For this literature review, the PICO framework was selected as the methodological approach. Our results demonstrated many methods by which this vitamin may lower the risk of ARTI with regard to the COVID-19 infection. Despite these significant advancements, more research is needed to support the idea that 25(OH)D concentration can influence the evolution of respiratory tract infections in children.

Neurological Symptoms That May Represent a Warning in Terms of Diagnosis and Treatment in a Group of Children and Adolescents with Vitamin D Deficiency

AIM

This research was intended to evaluate the clinical and laboratory findings of children presenting to our pediatric neurology clinic with symptoms potentially linked to vitamin D deficiency and with low vitamin D levels and the distribution of those findings by sex, age groups, and vitamin D levels.

METHODS

This retrospective study involved patients presenting to our clinic with symptoms potentially associated with vitamin D deficiency and low serum concentrations of 25 OH vitamin D (25 OH D) (<75 nmol/L, 30 µg/mL). Patients' movement disorders and central nervous system-related symptoms at the time of presentation and serum 25 OH D, calcium (Ca), phosphorus (P), and magnesium (Mg) levels were recorded and evaluated in terms of age, sex, and vitamin D levels.

RESULTS

Eight hundred twenty-two cases of vitamin D deficiency were included in the study, 50.2% (n = 413) boys and 49.8% (n = 409) girls. Although cases of vitamin D deficiency were present across all the age groups between 1 and 18, they were most common in the 5-14 age range (n = 372, 45.3%). Movement disorders were observed in 14.6% (n = 120) of our cases, and neurological findings associated with the central nervous system were observed in 52.6% (n = 432). The most common accompanying movement in our cases was difficulty remaining in balance (n = 42, 35%), while the most frequent accompanying central nervous system finding was vertigo (n = 99, 22.92%). Other movement disorders encountered included limb shaking (n = 32, 26.7%), abnormal posture (n = 20, 16.67%), easy falling (n = 16, 13.33%), body rigidity (n = 15, 12.5%), and hand clenching (n = 5, 4.17%). Other frequently encountered neurological findings were headache (n = 88, 20.37%), epileptic seizures (n = 83, 19.21%), fainting (n = 58, 13.43%), developmental delay (n = 41, 9.49%), febrile seizures (n = 33, 7.64%), and numbness in the fingers (n = 20, 4.63%). Other neurological findings were sleep disorders (n = 10, 2.31%), nightmares (n = 8, 1.85%), pain in the extremities (n = 7, 1.62%), and sweating and frailty (n = 4, 0.93% for both). Ca, P, and Mg levels were lower in cases with vitamin D levels < 12 µg/mL. The prevalences of both movement disorders and central nervous system findings varied according to age groups, sex, and vitamin D levels.

CONCLUSIONS

Our study results show that vitamin D deficiency can present with different neurological findings and that these may vary according to age group, sex, and vitamin D levels. Clinicians must take particular care in pediatric cases with neurological findings in terms of the early diagnosis and treatment of vitamin D deficiency.

Clarifying the Heterogeneity in Response to Vitamin D in the Development, Prevention, and Treatment of Type 2 Diabetes Mellitus: A Narrative Review

In this review, we explore the potential drivers of heterogeneity in response to Vitamin D (VitD) therapy, such as bioavailability, sex-specific response, and autoimmune pathology, in those at risk for and diagnosed with T2DM. In addition, we propose distinct populations for future interventions with VitD. The literature concerning VitD supplementation in the prevention, treatment, and remission of type 2 diabetes mellitus (T2DM) spans decades, is complex, and is often contradictory with mixed findings upon intervention. By association, VitD status is powerfully predictive with deficient subjects reporting greater risk for T2DM, conversion to T2DM from prediabetes, and enhanced response to VitD therapy. Preclinical models strongly favor intervention with VitD owing to the pleiotropic influence of VitD on multiple systems. Additional research is crucial as there remain many questions unanswered that are related to VitD status and conditions such as T2DM. Future research must be conducted to better understand the potentially spurious relationships between VitD status, supplementation, sun exposure, health behaviors, and the diagnosis and management of T2DM. Public health practice can greatly benefit from a better understanding of the mechanisms by which we can reliably increase VitD status and how this can be used to develop education and improve health behaviors.

Plasma Vitamin D levels in correlation with circulatory proteins could be a potential biomarker tool for pulmonary tuberculosis and treatment monitoring

BACKGROUND

Tuberculosis (TB), a life-threatening immune challenging disease to the global human community has to be diagnosed earlier and eliminated in the upcoming era. Vitamin D, a fat-soluble micronutrient, mainly from epidermal cells of the skin and a few dietary sources, is associated with the immune system in various disease management. Therefore, a better understanding of vitamin D metabolism and immune function in tuberculosis should be studied for the consideration of biomarkers.

METHODS

The study consist of Pulmonary Tuberculosis (PTB) patients (n = 32) at two-time points: Baseline (PTB BL) and after 6 months of anti-TB treatment (ATT) (PTB PT), latently Mtb infected (IFNγ + ) group (n = 32) and a non-LTB healthy control (IFNγ-) group (n = 32). Vitamin D levels were measured using High-performance liquid chromatography (HPLC). The cytokine data from the same participants assayed by ELISA from our earlier investigations were used to correlate it with serum Vitamin D levels.

RESULTS

The assayed serum Vitamin D levels between the groups showed significantly lowered levels in PTB BL when compared with IFNγ + and IFNγ- groups. And, the Vitamin D levels in the PTB group after ATT were significantly lower than the baseline levels. The Vitamin D data were compared with pro- and anti-inflammatory cytokines and adipokines levels by performing a principal component regression analysis. Based on the PC scores, the study group showed distinct clusters for the TB group and control group. And, the correlation analysis between the study group and immunological indices showed significant correlations. Vitamin D significantly correlated with IFNγ, TNFα, IL17A, IL-4 and Resistin in the TB group, whereas IL-6 and G-CSF in the control group.

CONCLUSION

The baseline measurement of Vitamin D levels was significantly decreased in the PTB group when compared with IFNγ + and IFNγ- groups showing the importance of Vitamin D as a preventive factor against the TB disease progression. The six-month post-treatment of TB showed a further decrease in Vitamin D levels in PTB. The significantly correlated immunological indices with Vitamin D levels are the biomarker profile that could predict TB.

The Role of Vitamin D in Reducing the Risk of Metabolic Disturbances That Cause Cardiovascular Diseases

Among the most common problems facing public health today is a lack of vitamin D, which plays a role in the physiological processes of chronic illness conditions. Vitamin D deficiency in metabolic disorders has primary effects on osteoporosis, obesity, hypertension, diabetes, and cardiovascular disease (CVD). Vitamin D acts as a "co-hormone" in the various tissues of the body, and it has been found that vitamin D receptors (VDR) are present on all cell types, suggesting that vitamin D has a wide range of effects on most cells. Recently, there has been a surge in interest in assessing its roles. Vitamin D insufficiency increases the risk of diabetes because it lowers insulin sensitivity, and also raises the risk of obesity and CVD because of its effect on the body's lipid profile, particularly in terms of the prevalence of dangerously high levels of low-density lipoproteins (LDL). Furthermore, vitamin D insufficiency is often related to CVD and connected risk factors, highlighting the need to know vitamin D's functions in relation to metabolic syndrome and related processes. Through looking at previous studies, this paper explains why vitamin D is important, how deficiency is related to risk factors for metabolic syndrome through different mechanisms, and how deficiency affects CVD.

1α,25-Dihydroxyvitamin D3 Regulates microRNA Packaging in Extracellular Matrix Vesicles and Their Release in the Matrix

Growth plate chondrocytes are regulated by numerous factors and hormones as they mature during endochondral bone formation, including transforming growth factor beta-1 (TGFb1), bone morphogenetic protein 2 (BMP2), insulin-like growth factor-1 (IFG1), parathyroid hormone and parathyroid hormone related peptide (PTH, PTHrP), and Indian hedgehog (IHH). Chondrocytes in the growth plate's growth zone (GC) produce and export matrix vesicles (MVs) under the regulation of 1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃]. 1α,25(OH)₂D₃ regulates MV enzyme composition genomically and 1α,25(OH)₂D₃ secreted by the cells acts on the MV membrane nongenomically, destabilizing it and releasing MV enzymes. This study examined the regulatory role 1α,25(OH)₂D₃ has over production and packaging of microRNA (miRNA) into MVs by GC cells and the release of miRNA by direct action on MVs. Costochondral cartilage GC cells were treated with 1α,25(OH)₂D₃ and the miRNA in the cells and MVs sequenced. We also treated MVs with 1α,25(OH)₂D₃ and determined if the miRNA was released. To assess whether MVs can act directly with chondrocytes and if this is regulated by 1α,25(OH)₂D₃, we stained MVs with a membrane dye and treated GC cells with them. 1α,25(OH)₂D₃ regulated production and packaging of a unique population of miRNA into MVs compared to the vehicle control population. 1α,25(OH)₂D₃ treatment of MVs did not release miRNA. Stained MVs were endocytosed by GC cells and this was increased with 1α,25(OH)₂D₃ treatment. This study adds new regulatory roles for 1α,25(OH)₂D₃ with respect to packaging and transport of MV miRNAs.

Single Nucleotide Polymorphisms in the Vitamin D Metabolic Pathway and Their Relationship with High Blood Pressure Risk

High blood pressure (HBP) is the leading risk factor for cardiovascular disease (CVD) and all-cause mortality worldwide. The progression of the disease leads to structural and/or functional alterations in various organs and increases cardiovascular risk. Currently, there are significant deficiencies in its diagnosis, treatment, and control. Vitamin D is characterized by its functional versatility and its involvement in countless physiological processes. This has led to the association of vitamin D with many chronic diseases, including HBP and CVD, due to its involvement in the regulation of the renin-angiotensin-aldosterone system. The aim of this study was to evaluate the effect of 13 single nucleotide polymorphisms (SNPs) related to the vitamin D metabolic pathway on the risk of developing HBP. An observational case-control study was performed, including 250 patients diagnosed with HBP and 500 controls from the south of Spain (Caucasians). Genetic polymorphisms in CYP27B1 (rs4646536, rs3782130, rs703842, and rs10877012), CYP2R1 rs10741657, GC rs7041, CYP24A1 (rs6068816, and rs4809957), and VDR (BsmI, Cdx2, FokI, ApaI, and TaqI) were analyzed by real-time PCR using TaqMan probes. Logistic regression analysis, adjusted for body mass index (BMI), dyslipidemia, and diabetes, showed that in the genotypic model, carriers of the GC rs7041 TT genotype were associated with a lower risk of developing HBP than the GG genotype (odds ratio (OR) = 0.44, 95% confidence interval (CI): 0.41-0.77, p = 0.005, TT vs. GG). In the dominant model, this association was maintained; carriers of the T allele showed a lower risk of developing HBP than carriers of the GG genotype (OR = 0.69, 95% CI: 0.47-1.03; TT + TG vs. GG, p = 0.010). Finally, in the additive model, consistent with previous models, the T allele was associated with a lower risk of developing HBP than the G allele (OR = 0.65, 95% CI: 0.40-0.87, p = 0.003, T vs. G). Haplotype analysis revealed that GACATG haplotypes for SNPs rs1544410, rs7975232, rs731236, rs4646536, rs703842, and rs10877012 were associated with a marginally significant lower risk of developing HBP (OR = 0.35, 95% CI: 0.12-1.02, p = 0.054). Several studies suggest that GC 7041 is associated with a lower active isoform of the vitamin D binding protein. In conclusion, the rs7041 polymorphism located in the GC gene was significantly associated with a lower risk of developing HBP. This polymorphism could therefore act as a substantial predictive biomarker of the disease.

Potential Role of Vitamin D, ACE2 and the Proteases as TMPRSS2 and Furin on SARS-CoV-2 Pathogenesis and COVID-19 Severity

BACKGROUND

COVID-19, the 21^st century pandemic disease caused by SARS-CoV-2, has shown a wide clinical spectrum ranging from asymptomatic to deadly serious pneumonia.

OBJECTIVE

In our study, the relationship between the pathogenesis and clinical severity of COVID-19 and vitamin D, ACE2, Furin and TMPRSS2 was investigated.

METHODS

Serum 25(OH)D, 1,25(OH)₂D and ACE2 protein were measured in 85 COVID-19 cases, divided into 5 groups, according to disease severity, from asymptomatic to severe and including a healthy control group. Expression levels of ACE2, VDR, TMPRSS2 and Furin mRNAs in PBMC were also measured. The relationship of the parameters within each group, the severity of the disease and the effect on the patients' fate were investigated.

RESULTS

Statistically significant differences were found between the severity of COVID-19 and all study parameters, except for serum 25(OH)D. A strong negative correlation was found between serum ACE2 protein, 1,25(OH)₂D, and ACE2 mRNA, and disease severity, length of hospital stay and death/survival rate. Vitamin D deficiency increased the death risk by 5.6-fold (95% CI 0.75-41.47), and the levels of 1,25(OH)₂D lower than 1 ng/mL increased the risk of death by 3.8-fold (95% CI 1.07-13.30).

CONCLUSION

This study suggests that vitamin D supplementation could be beneficial in the treatment and/or prevention of COVID-19.

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

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

Serum vitamin D levels and peak cough flow in patients with subacute ischemic stroke

Aspiration pneumonia is a major, potentially fatal complication after ischemic stroke. Decreased coughing function is a significant risk factor for aspiration in ischemic stroke survivors. Peak cough flow (PCF) is a useful tool for assessing cough function. Vitamin D deficiency is frequent after ischemic stroke and is linked to a variety of muscle functions and physical activities. There has been no investigation of the correlation between vitamin D levels and PCF in ischemic stroke survivors. This study aimed to examine the relationship between serum vitamin D levels and PCF in patients with ischemic stroke. Patients with ischemic stroke who underwent PCF evaluation and serum vitamin D level measurements within 1 month of onset were retrospectively recruited. The association between PCF parameters and serum vitamin D levels was also analyzed. In total, 142 patients with ischemic stroke were included. PCF parameters and serum vitamin D levels were found to be significantly correlated. Moreover, serum vitamin D levels were shown to be a significant predictor of PCF parameters. Serum vitamin D levels were related to PCF parameters in patients with ischemic stroke. In addition, serum vitamin D level may serve as a predictor of coughing function in patients with ischemic stroke.

The enigma of vitamin D supplementation in aging with obesity

INTRODUCTION

The American Geriatrics Society recommends a minimum daily supplement of 1,000 IU and underlines that a dosage lower than 600 IU do not prevent falls in elderly people.

EVIDENCE ACQUISITION

The author searched on PubMed, Medline, Embase, Scopus database the MeSH terms and keywords of "vitamin D," "(25(OH)D)," "elderly" and "obesity." The aim of this study was to support the rationale on the correct vitamin D supplementation in elderly people with obesity and overweight.

EVIDENCE SYNTHESIS

Ten studies were found suitable for consideration in writing this comprehensive evidence-based rapid review. The supplementation of vitamin D included 1500 elderly subjects with Body Mass Index (BMI) over 25 kg/m². This article proved that the daily vitamin D supplementation from 2000 to 4000 UI is highly recommended in elderly people with obesity because of: 1) sequestration of vitamin D by the adipose tissue; 2) increased catabolism of vita-in D in the adipose tissue; 3) decreased synthesis of serum 25 hydroxyvitamin D (25(OH)D) in the liver; 4) reduced sun-exposure; and 5) dosages equal at 1000 UI or lower that did not show any important effect on vitamin D deficiency and on related comorbidities in elderly people with obesity.

CONCLUSIONS

Gender, baseline levels of serum (25(OH)D) concentration, ethnicity and severity of BMI should be accounted for the correct supplementation of vitamin D in elderly population for the precision medicine goal.

Vitamin D in the Treatment of Oral Lichen Planus: A Systematic Review

Oral lichen planus (OLP) is a chronic mucocutaneous condition that affects up to 2% of the general population, and typically presents with long-standing, non-responsive lesions, with episodes of exacerbation and remissions. The etiopathogenesis of OLP is still unclear, although, it has been postulated that it is most likely a T-cell-mediated condition of an unknown antigen. The treatment remains a challenge with no defined treatment strategy. Vitamin D has anti-inflammatory and immunomodulatory properties, along with its regulatory effect on keratinocyte proliferation and differentiation; thus, suggesting its possible role in the treatment of OLP. This systematic review aims to evaluate the therapeutic role of vitamin D in OLP treatment. We searched PubMed/MEDLINE, and Google scholar search engines for studies evaluating vitamin D as a treatment modality in OLP from January 2000 to August 2022. Articles were searched with the combination of Medical Subject Heading (MeSH) terms. A web platform for visualizing risk-of-bias assessment was used in this review, and descriptive statistics were calculated. Out of the seventeen retrieved studies, five articles meeting the inclusion criteria were considered in this systematic review. All the included studies demonstrated significant amelioration in the OLP symptoms in patients who were given vitamin D supplements as an adjuvant to the conventional steroid therapy and or placebo. This systematic review signifies the role of vitamin D as adjuvant therapy for OLP. However, more studies with larger sample size are required to validate these results.

Effect of Single Nucleotide Polymorphisms in the Vitamin D Metabolic Pathway on Susceptibility to Non-Small-Cell Lung Cancer

The pathogenesis of non-small-cell lung cancer (NSCLC) is complex, since many risk factors have been identified. Recent research indicates that polymorphisms in the metabolic pathway of vitamin D may be involved in both risk and survival of the disease. The objective of this study is to assess the effect of 13 genetic polymorphisms involved in the vitamin D metabolic pathway on the risk of suffering from NSCLC. We conducted an observational case-control study, which included 204 patients with NSCLC and 408 controls, of Caucasian origin, from southern Spain. The CYP27B1 (rs4646536, rs3782130, rs703842, rs10877012), CYP2R1 (rs10741657), GC (rs7041), CYP24A1, and VDR (BsmI, Cdx-2, FokI, ApaI, TaqI) gene polymorphisms were analyzed by real-time polymerase chain reaction. The logistic regression model, adjusted for smoking and family history of cancer, revealed that in the genotypic model, carriers of the VDR BsmI rs1544410-AA genotype were associated with a lower risk of developing NSCLC compared to the GG genotype (p = 0.0377; OR = 0.51; CI95% = 0.27-0.95; AA vs. GG). This association was maintained in the recessive model (p = 0.0140). Haplotype analysis revealed that the AACATGG and GACATGG haplotypes for the rs1544410, rs7975232, rs731236, rs4646536, rs703842, rs3782130, and rs10877012 polymorphisms were associated with a lower risk of NSCLC (p = 0.015 and p = 0.044 respectively). The remaining polymorphisms showed no effect on susceptibility to NSCLC. The BsmI rs1544410 polymorphism was significantly associated with lower risk of NSCLC and could be of considerable value as a predictive biomarker of the disease.

Changes in Metabolic Parameters in Patients with Diabetic Kidney Disease Depending on the Status of D3

BACKGROUND

Type 2 diabetes is a metabolic disease characterized by hyperglycemia as a result of insulin resistance and decreased insulin secretion. A relatively large number of patients with this type of diabetes have abdominal obesity, which also affects insulin resistance development. Chronic hyperglycemia can lead to damage and dysfunction of various organs, and a striking example is diabetic nephropathy. Diabetic nephropathy is a specific kind of kidney damage that occurs due to complications of diabetes and is accompanied by the formation of diffuse or nodular glomerulosclerosis, which can lead to terminal renal failure and requires immediate substitution through renal therapy or renal transplantation. Diabetic nephropathy is diagnosed with albuminuria and a decrease in the rate of glomerular filtration.

METHODS

This review was based on a literature search for the most important evidence of vitamin D as a possible method of prevention for obesity, type 2 diabetes, and diabetic nephropathy. Collected published articles were summarized according to their overall themes.

RESULTS

In this review, we considered vitamin D as a possible method of treatment for type 2 diabetes, as well as its complications, including diabetic nephropathy.

CONCLUSION

Studies show that vitamin D inhibits the renin-angiotensin-aldosterone system, resulting in improved renal function in diabetic nephropathy. Vitamin D also has antiinflammatory, antiproliferative, and anti-metastatic effects, which improve endothelial function.

Bovine Immunity and Vitamin D3: An Emerging Association in Johne's Disease

Mycobacterium avium subspecies paratuberculosis (MAP) is an environmentally hardy pathogen of ruminants that plagues the dairy industry. Hallmark clinical symptoms include granulomatous enteritis, watery diarrhea, and significant loss of body condition. Transition from subclinical to clinical infection is a dynamic process led by MAP which resides in host macrophages. Clinical stage disease is accompanied by dysfunctional immune responses and a reduction in circulating vitamin D3. The immunomodulatory role of vitamin D3 in infectious disease has been well established in humans, particularly in Mycobacterium tuberculosis infection. However, significant species differences exist between the immune system of humans and bovines, including effects induced by vitamin D3. This fact highlights the need for continued study of the relationship between vitamin D3 and bovine immunity, especially during different stages of paratuberculosis.

The Role of Vitamin D and Vitamin D Binding Protein in Chronic Liver Diseases

Vitamin D (calciferol) is a fat-soluble vitamin that has a significant role in phospho-calcium metabolism, maintaining normal calcium levels and bone health development. The most important compounds of vitamin D are cholecalciferol (vitamin D3, or VD3) and ergocalciferol (vitamin D2, or VD2). Besides its major role in maintaining an adequate level of calcium and phosphate concentrations, vitamin D is involved in cell growth and differentiation and immune function. Recently, the association between vitamin D deficiency and the progression of fibrosis in chronic liver disease (CLD) was confirmed, given the hepatic activation process and high prevalence of vitamin D deficiency in these diseases. There are reports of vitamin D deficiency in CLD regardless of the etiology (chronic viral hepatitis, alcoholic cirrhosis, non-alcoholic fatty liver disease, primary biliary cirrhosis, or autoimmune hepatitis). Vitamin D binding protein (VDBP) is synthesized by the liver and has the role of binding and transporting vitamin D and its metabolites to the target organs. VDBP also plays an important role in inflammatory response secondary to tissue damage, being involved in the degradation of actin. As intense research during the last decades revealed the possible role of vitamin D in liver diseases, a deeper understanding of the vitamin D, vitamin D receptors (VDRs), and VDBP involvement in liver inflammation and fibrogenesis could represent the basis for the development of new strategies for diagnosis, prognosis, and treatment of liver diseases. This narrative review presents an overview of the evidence of the role of vitamin D and VDBP in CLD, both at the experimental and clinical levels.

Effects of Vitamin D Receptor Genotype on Lipid Profiles and Retinopathy Risk in Type 2 Diabetes Patients: A Pilot Study

Genetic polymorphisms affect lipid profiles and are associated with disease complications. Genetic variants in the vitamin D receptor (VDR) gene are associated with type 2 diabetes mellitus (T2DM). In this study, we investigated the effects of VDR genotypes on the lipid profile and disease complications of T2DM patients in a Jordanian population. Ninety T2DM patients were genotyped for four major functional VDR genetic variants, rs2228570 C > T (FokI), rs7975232 A > C (ApaI), rs731236 T > C (TaqI), and rs1544410 C > T (BsmI), using the polymerase chain reaction−restriction fragment length polymorphism method. Lipid profiles and diabetes complications were analyzed and correlated with VDR genotypes. We found that the VDR rs7975232 and rs1544410 alleles were significantly (p = 0.008−0.04) associated with high-density lipoprotein (HDL) levels and retinopathy among patients. Carriers of the rs7975232 A/A genotype exhibited higher levels (49.68 ± 15.86 mg/dL) of HDL than patients with the A/C (44.73 ± 13.38 mg/dL) and C/C (37.93 ± 9.22 mg/dL) genotypes. Moreover, carriers of the rs1544410 T/T genotype had higher levels of HDL (54.31 ± 16.45 mg/dL) than patients with the C/T (43.57 ± 13.24 mg/dL) and C/C (43.98 ± 13.17 mg/dL) genotypes. T2DM patients who carry the rs7975232 C/C genotype were at higher risk (odds ratio [OR] = 7.88) of developing retinopathy compared with carriers of the rs7975232 C/A and A/A genotypes. In addition, T2DM patients with the rs1544410 C/C genotype had a higher risk (OR = 4.21) of developing retinopathy than patients with the rs1544410 C/T and T/T genotypes. Therefore, we concluded that the VDR rs7975232 and rs1544410 alleles were associated with HDL levels and retinopathy and can be considered as potential genetic biomarkers for the lipid profile and retinopathy complication among T2DM patients in a Jordanian population of Arabic origin. Further studies with larger sample sizes are needed to confirm our findings.

Genetic Polymorphisms Associated with Perioperative Joint Infection following Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

The number of orthopedic procedures, especially prosthesis implantation, continues to increase annually, making it imperative to understand the risks of perioperative complications. These risks include a variety of patient-specific factors, including genetic profiles. This review assessed the current literature for associations between patient-specific genetic risk factors and perioperative infection. The PRISMA guidelines were used to conduct a literature review using the PubMed and Cochrane databases. Following title and abstract review and full-text screening, eight articles remained to be reviewed—all of which compared single nucleotide polymorphisms (SNPs) to periprosthetic joint infection (PJI) in total joint arthroplasty (TJA). The following cytokine-related genes were found to have polymorphisms associated with PJI: TNFα (p < 0.006), IL-6 (p < 0.035), GCSF3R (p < 0.02), IL-1 RN-VNTR (p = 0.002), and IL-1B (p = 0.037). Protein- and enzyme-related genes that were found to be associated with PJI included: MBL (p < 0.01, p < 0.05) and MBL2 (p < 0.01, p < 0.016). The only receptor-related gene found to be associated with PJI was VDR (p < 0.007, p < 0.028). This review compiled a variety of genetic polymorphisms that were associated with periprosthetic joint infections. However, the power of these studies is low. More research must be conducted to further understand the genetic risk factors for this serious outcome.

Pivotal role of vitamin D in mitochondrial health, cardiac function, and human reproduction

Vitamin D, a secosteroid hormone, appears to have significant beneficial effects on various physiological systems, including the musculoskeletal system. Vitamin D assists in the regulation of numerous critical biological functions and physiological processes in humans, including inflammation, oxidative stress, and mitochondrial respiration, and is also linked to cardiac diseases. It is also reported that vitamin D plays a central role in molecular and cellular mechanisms, which reduce oxidative stress, and tissue damage and regulate cellular health. On the other side, hypovitaminosis D reduces mitochondrial activity and increases oxidative stress and inflammation in the body. Hypervitaminosis D increases the prevalence and severity of cellular damage. It has also been reported that vitamin D is involved in many functions of the reproductive system in human and critically play an important role in the reproductive tissues of women and men. Its role is very well defined, starting from female menarche to menopause, pregnancy, and lactation, and finally in male fertility. Hence, the appropriate amount of vitamin D is necessary to maintain the normal function of cell organelles. Based on recent studies, it is understood that vitamin D is involved in the biological activities of mitochondria in cells, especially in cardiomyocytes. In this review, we emphasized the role of vitamin D in mitochondrial respiration, which could significantly influence heart health and human reproduction.

Carboranes in drug discovery, chemical biology and molecular imaging

There exists a paucity of structural innovation and limited molecular diversity associated with molecular frameworks in drug discovery and biomolecular imaging/chemical probe design. The discovery and exploitation of new molecular entities for medical and biological applications will necessarily involve voyaging into previously unexplored regions of chemical space. Boron clusters, notably the carboranes, offer an alternative to conventional (poly)cyclic organic frameworks that may address some of the limitations associated with the use of novel molecular frameworks in chemical biology or medicine. The high thermal stability, unique 3D structure and aromaticity, kinetic inertness to metabolism and ability to engage in unusual types of intermolecular interactions, such as dihydrogen bonds, with biological receptors make carboranes exquisite frameworks in the design of probes for chemical biology, novel drug candidates and biomolecular imaging agents. This Review highlights the key developments of carborane derivatives made over the last decade as new design tools in medicinal chemistry and chemical biology, showcasing the versatility of this unique family of boron compounds.

Long-Term Vitamin D Deficiency Results in the Inhibition of Cell Proliferation and Alteration of Multiple Gastric Epithelial Cell Lineages in Mice

Over one billion people globally are vitamin D (VD) deficient. Studies on the biological roles of VD are numerous but very little on the stomach. This project aims to understand how gastric homeostasis is affected by VD deficiency caused by prolonged exposure to darkness alone or combined with VD deficient diet. Three groups of C57/BL6 mice were subjected to different light exposure conditions and diets for 12 months (n = 8−12/group): control—12 h/12 h light/dark SDL (Standard Diet/Light), 24 h dark SDD (Standard Diet/Dark), and 24 h dark VDD (VD deficient diet/Dark). Stomach samples were collected for different multi-label lectin-/immuno-histochemical and qRT-PCR analyses, and the serum for LC-MS-MS. We found that the membrane VD receptor is expressed widely in the stomach when compared to nuclear VD receptors. Compared to SDL, VDD mice developed mucous cell expansion with increased mucins-mRNA (3.27 ± 2.73 (p < 0.05)) increased apoptotic cells, 15 ± 7 (p ≤ 0.001)); decreased cell proliferation, 4 ± 4 (p < 0.05)) and decreased acid secretion 33 ± 2 μEq/kg (p ≤ 0.0001)). Interestingly, mice exposed to full darkness developed mild VD deficiency with higher VD epimer levels: 11.9 ± 2.08 ng/mL (p ≤ 0.0001)), expansion in zymogenic cell number (16 ± 3 (p ≤ 0.01)), and a reduction in acid secretion (18 ± 2 μEq/kg (p ≤ 0.0001)). In conclusion, changes in light exposure or VD levels have serious physiological effects on the gastric mucosa, which should be considered during the management of gastric disorders.

Nanocarriers for Drug Delivery: An Overview with Emphasis on Vitamin D and K Transportation

Mounting evidence shows that supplementation with vitamin D and K or their analogs induces beneficial effects in various diseases, e.g., osteoarticular, cardiovascular, or carcinogenesis. The use of drugs delivery systems via organic and inorganic nanocarriers increases the bioavailability of vitamins and analogs, enhancing their cellular delivery and effects. The nanotechnology-based dietary supplements and drugs produced by the food and pharmaceutical industries overcome the issues associated with vitamin administration, such as stability, absorption or low bioavailability. Consequently, there is a continuous interest in optimizing the carriers' systems in order to make them more efficient and specific for the targeted tissue. In this pioneer review, we try to circumscribe the most relevant aspects related to nanocarriers for drug delivery, compare different types of nanoparticles for vitamin D and K transportation, and critically address their benefits and disadvantages.

The Role of Exercise-Induced Molecular Processes and Vitamin D in Improving Cardiorespiratory Fitness and Cardiac Rehabilitation in Patients With Heart Failure

Heart failure (HF) still affects millions of people worldwide despite great advances in therapeutic approaches in the cardiovascular field. Remarkably, unlike pathological hypertrophy, exercise leads to beneficial cardiac hypertrophy characterized by normal or enhanced contractile function. Exercise-based cardiac rehabilitation improves cardiorespiratory fitness and, as a consequence, ameliorates the quality of life of patients with HF. Particularly, multiple studies demonstrated the improvement in left ventricular ejection fraction (LVEF) among patients with HF due to the various processes in the myocardium triggered by exercise. Exercise stimulates IGF-1/PI3K/Akt pathway activation involved in muscle growth in both the myocardium and skeletal muscle by regulating protein synthesis and catabolism. Also, physical activity stimulates the activation of the mitogen-activated protein kinase (MAPK) pathway which regulates cellular proliferation, differentiation and apoptosis. In addition, emerging data pointed out the anti-inflammatory effects of exercises as well. Therefore, it is of utmost importance for clinicians to accurately evaluate the patient’s condition by performing a cardiopulmonary exercise test and/or a 6-min walking test. Portable devices with the possibility to measure exercise capacity proved to be very useful in this setting as well. The aim of this review is to gather together the molecular processes triggered by the exercise and available therapies in HF settings that could ameliorate heart performance, with a special focus on strategies such as exercise-based cardiac rehabilitation.

New Variants of the Cytochrome P450 2R1 (CYP2R1) Gene in Individuals with Severe Vitamin D-Activating Enzyme 25(OH)D Deficiency

BACKGROUND

Vitamin D is a fat-soluble cholesterol derivative found in two forms, vitamin D2, and vitamin D3. Cytochrome P450 2R1 (CYP2R1) encoded by the CYP2R1 gene is the major hydroxylase that activates vitamin D by catalyzing the formation of 25-hydroxyvitamin D (25(OH)D).

METHODS

We collected 89 (100%) subjects, 46 of which (51.69%) had a documented severe deficiency of 25(OH)D (<10 ng/mL) and 43 (48.31%) in the control group with documented optimum levels of 25(OH)D (>30 ng/mL). We performed Sanger sequencing of three selected fragments of the CYP2R1 gene (Ch11: 14878000-14878499; Ch11: 14880058-14880883 and Ch11: 14885321-14886113) that affect the binding of substrates to this enzyme and analyzed the possible involvement of genetic variation in these regions with an increased risk of vitamin D deficiency in healthy Polish individuals.

RESULTS

Two substitutions were found within the three fragments. Bioinformatic analysis suggested that one of these (NC_000011.10: g.14878291G>A) may influence the structure and function of CYP2R1.

CONCLUSIONS

Variant NC_000011.10: g.14878291G>A may have a perturbing effect on heme binding in the active site of CYP2R1 and on the function of 25-hydroxylase and probably affects the concentration of 25(OH)D in vivo. We intend to perform functional verification in a larger patient population to confirm and extend these results.

Mucosal defense: gastroduodenal injury and repair mechanisms

PURPOSE OF REVIEW

The mucosal barrier serves as a primary interface between the environment and host. In daily life, superficial injury to the gastric or duodenal mucosa occurs regularly but heals rapidly by a process called 'restitution'. Persistent injury to the gastroduodenal mucosa also occurs but initiates a regenerative lesion with specific wound healing mechanisms that attempt to repair barrier function. If not healed, these lesions can be the site of neoplasia development in a chronic inflammatory setting. This review summarizes the past year of advances in understanding mucosal repair in the gastroduodenal mucosa, which occurs as a defense mechanism against injury.

RECENT FINDINGS

Organoids are an emerging new tool that allows for the correlation of in vivo and in vitro models; organoids represent an important reductionist model to probe specific aspects of injury and repair mechanisms that are limited to epithelial cells. Additionally, proof-of-concept studies show that machine learning algorithms may ultimately assist with identifying novel, targetable pathways to pursue in therapeutic interventions. Gut-on-chip technology and single cell RNA-sequencing contributed to new understanding of gastroduodenal regenerative lesions after injury by identifying networks and interactions that are involved in the repair process.

SUMMARY

Recent updates provide new possibilities for identifying novel molecular targets for the treatment of acute and superficial mucosal injury, mucosal regeneration, and regenerative lesions in the gastrointestinal tract.

Sources of vitamin D for humans

Both vitamin D insufficiency and deficiency are now well-documented worldwide in relation to human health, and this has raised interest in vitamin D research. The aim of this article is therefore to review the literature on sources of vitamin D. It can be endogenously synthesised under ultraviolet B radiation in the skin, or ingested through dietary supplements and dietary sources, which include food of animal and plant origin, as well as fortified foods. Vitamin D is mainly found in two forms, D₃ (cholecalciferol) and D₂ (ergocalciferol). In addition to the D₃ and D₂ forms of vitamin D, 25-hydroxy vitamin D also contributes significantly to dietary vitamin D intake. It is found in many animal-derived products. Fortified food can contain D₃ or D₂ forms or vitamin D metabolite 25-hydroxy vitamin D. Not many foods are a rich source (> 4 μg/100 g) of vitamin D (D represents D₃ and/or D₂), e.g., many but not all fish (5-25 μg/100 g), mushrooms (21.1-58.7 μg/100 g), Reindeer lichen (87 μg/100 g) and fish liver oils (250 μg/100 g). Other dietary sources are cheese, beef liver and eggs (1.3-2.9 μg/100 g), dark chocolate (4 μg/100 g), as well as fortified foods (milk, yoghurt, fat spreads, orange juice, breakfast grains, plant-based beverages). Since an adequate intake of vitamin D (15 μg/day set by the European Food Safety Authority) is hard to achieve through diet alone, dietary supplements of vitamin D are usually recommended. This review summarizes current knowledge about different sources of vitamin D for humans.

Vitamin D and COVID-19: A review on the role of vitamin D in preventing and reducing the severity of COVID-19 infection

Severe Acute Respiratory Syndrome Coronavirus‐2 (SARS‐CoV‐2) is a pathogenic coronavirus causing COVID‐19 infection. The interaction between the SARS‐CoV‐2 spike protein and the human receptor angiotensin‐converting enzyme 2, both of which contain several cysteine residues, is impacted by the disulfide‐thiol balance in the host cell. The host cell redox status is affected by oxidative stress due to the imbalance between the reactive oxygen/nitrogen species and antioxidants. Recent studies have shown that Vitamin D supplementation could reduce oxidative stress. It has also been proposed that vitamin D at physiological concentration has preventive effects on many viral infections, including COVID‐19. However, the molecular‐level picture of the interplay of vitamin D deficiency, oxidative stress, and the severity of COVID‐19 has remained unclear. Herein, we present a thorough review focusing on the possible molecular mechanism by which vitamin D could alter host cell redox status and block viral entry, thereby preventing COVID‐19 infection or reducing the severity of the disease.

How FGF23 shapes multiple organs in chronic kidney disease

Chronic kidney disease (CKD) is associated with distinct alterations in mineral metabolism in children and adults resulting in multiple organ dysfunctions. Children with advanced CKD often suffer from impaired bone mineralization, bone deformities and fractures, growth failure, muscle weakness, and vascular and soft tissue calcification, a complex which was recently termed CKD-mineral and bone disorder (CKD-MBD). The latter is a major contributor to the enhanced cardiovascular disease comorbidity and mortality in these patients. Elevated circulating levels of the endocrine-acting phosphaturic hormone fibroblast growth factor (FGF) 23 are the first detectable alteration of mineral metabolism and thus CKD-MBD. FGF23 is expressed and secreted from osteocytes and osteoblasts and rises, most likely due to increased phosphate load, progressively as kidney function declines in order to maintain phosphate homeostasis. Although not measured in clinical routine yet, CKD-mediated increased circulating levels of FGF23 in children are associated with pathological cardiac remodeling, vascular alterations, and increased cognitive risk. Clinical and experimental studies addressing other FGF23-mediated complications of kidney failure, such as hypertension and impaired bone mineralization, show partly conflicting results, and the causal relationships are not always entirely clear. This short review summarizes regulators of FGF23 synthesis altered in CKD and the main CKD-mediated organ dysfunctions related to high FGF23 levels.

Association of Perioperative Complications with Vitamin D Levels in Major Head and Neck Surgery

OBJECTIVES/HYPOTHESIS

To investigate the association of vitamin D level and perioperative complications in patients undergoing major head and neck surgery.

STUDY DESIGN

Retrospective Cohort Study.

METHODS

A retrospective chart review was performed for all patients undergoing reconstructive head and neck surgery between December 2017 and December 2019. Data regarding patient demographics, serum 25-hydroxyvitamin D (calcidiol) level, hospital course, prior radiation, and fistula formation were collected. Patients were categorized by serum calcidiol level as deficient (<20 ng/mL) or sufficient (≧20 ng/mL) and outcomes were compared between groups.

RESULTS

Fifty-seven patients were included in the analysis. Average age at time of surgery was 62.6 ± 10.6 years. Patients with vitamin D levels <20 ng/mL were considered deficient and ≧20 ng/mL were considered sufficient. Individuals in the deficient group (n = 29) had a mean serum calcidiol level of 13.95 ± 3.95 ng/mL, whereas those in the sufficient group (n = 28) had a mean calcidiol level of 28.53 ± 5.73 ng/mL. The rate of fistula was 41.4% in the deficient group, whereas patients in the sufficient group had a rate of fistula of 14.3% (P = .038). On multivariate analysis, higher serum calcidiol level above 20 ng/mL was associated with a lower likelihood of developing fistulae with an odds ratio 0.830 (95% confidence interval: 0.718-0.960, P = .012).

CONCLUSION

Vitamin D deficiency may play a role in development of fistula after major head and neck surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Narrative role of vitamin D receptor with osteoporosis and obesity in a sample of Egyptian females: a pilot study

BACKGROUND

Vitamin D receptor (VDR) is known as one of the cellular regulators for several metabolic pathways indicating its pivotal role in the pathological pathway of numerous diseases. Considering the high frequency of osteoporosis and obesity among women, the current study aimed to explore the prospective assembly of the most frequent two VDR loci, single nucleotide polymorphism SNPs rs731236 (TaqI) and rs7975232 (ApaI) with a genetic predisposition to osteoporosis (skeletal) and obesity (chronic non-skeletal disorders), in Egyptian women. This was a cross-sectional study, including 97 Egyptian females (25-65 years), randomly chosen, from all employees and workers of the National Research Centre, Egypt. Anthropometric measurements (weight, height, BMI), dual-energy X-ray absorptiometry (DEXA), and molecular genetic analysis were done.

RESULTS

The variation of ApaI genotype between the normal and osteoporotic groups denotes a remarkable association of the homozygote ApaI genotype with osteoporosis risk. Among the normal weight group, bone mineral density (BMD) was significantly associated with TaqI VDR gene polymorphism as the presence of the heterozygote genotype was accompanied with higher BMD while the homozygote one was detected with lower BMD. Also, TaqI VDR gene polymorphism was significantly associated with BMI when participants were divided according to the presence of osteoporosis; increased BMI was expressed in the non-osteoporotic women group carrying the homozygote genotype of Taq I VDR gene while the presence of the heterozygote genotype (TaqI) in the osteoporotic group was associated with increased BMI.

CONCLUSIONS

The heterozygote TaqI genotype is protective against the osteoporosis phenotype and accompanied with increased BMI among osteoporotic women, while the homozygote ApaI genotype has a significant association with osteoporosis risk.

A Non-Invasive Hair Test to Determine Vitamin D3 Levels

Vitamin D deficiency is being recognized as a global issue and has been implicated in many health issues. Hence, there is an increased interest in developing sensitive, reproducible, and non-invasive assays to measure Vitamin D levels. This study aimed to apply a sensitive liquid chromatography-mass spectrometric assay to hair samples to develop and validate a clinical assay to provide a quarterly average level of vitamin D in one test. Hair samples were collected from 70 male university students/young adults and pulverized/sonicated in methanol/water for 2 h to extract Vitamin D metabolites. A sensitive liquid chromatographic-mass spectrometric assay was employed to quantitate vitamin D and metabolites. Of the eight Vitamin D and metabolites screened, only the primary, clinically significant form of vitamin D (25OHD₃) was detected and quantified in hair samples in the range of 17-1541 pg/mg. One-third of the hair samples (21 out of 70) had Vitamin D levels below the LLOD of the assay (10 pg/mg). The mean and standard deviation values for hair (25OHD₃) were 276.7 ± 329.9, respectively. This pilot study reveals the potential of the vitamin D hair test in clinical assays as a complementary test to a vitamin D blood test, which would provide a quarterly average.