Effect of vitamin D supplementation on cathelicidin, IFN-γ, IL-4 and Th1/Th2 transcription factors in young healthy females. Eur J Clin Nutr. 2014;68:338-343. [PMID: 24398649 DOI: 10.1038/ejcn.2013.268]

Weekly Vitamin D Supplementation to Prevent Acute Respiratory Infections in Young Children at Different Latitudes: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effectiveness of weekly vitamin D supplementation in reducing the number of acute respiratory infections (ARI) in preschool children.

STUDY DESIGN

Randomized, double-blind, placebo-controlled trial in 303 children aged 1.5-3.5 years from 2014 to 2105 in 3 Chilean cities at different latitudes: Santiago (33°S, n = 101), Talcahuano (37°S, n = 103), and Punta Arenas (53°S, n = 99). Participants were allocated (1:1:1) to receive placebo, cholecalciferol (vitamin D3 (VD3)) 5600 IU/week (low-dose), or 11 200 IU/week (high-dose) for 6 months. Primary outcome was parent-reported number of ARI; secondary outcomes included number of ARI hospitalizations, change of serum 25-hydroxyvitamin D (25(OH)D) and LL-37/cathelicidin levels, and adverse events.

RESULTS

The mean age of participants was 26 ± 6 months; 45% were female. Baseline 25(OH)D was 24.9 ± 6.1 ng/ml, with 23% having 25(OH)D <20 ng/ml. No significant baseline clinical or laboratory differences were observed among groups. Overall, 64% (n = 194) completed study participation, without baseline differences between subjects lost to follow-up vs those completing participation or differences in completion rates across groups. After 6 months, a dose-dependent increase in serum 25(OH)D was observed from the VD3 intervention (P < .001), with a higher proportion of subjects ending the trial with 25(OH)D <20 ng/ml in the placebo group (30.8%) vs the low-dose (7.4%) and high-dose groups (5.1%). However, no group differences were observed in number of ARI (P = .85), ARI hospitalizations (P = .20), LL-37/cathelicidin change (P = .30), or adverse events (P = .41).

CONCLUSIONS

While weekly VD3 supplementation, in doses equivalent to 800 IU and 1600 IU daily, was associated with improved 25(OH)D levels in preschoolers, we did not find a reduced number of ARI in this sample.

Trabecular bone score norms in Asian-Indians and associations with serum 25(OH)D and parathyroid hormone

OBJECTIVE

There is limited information on population-specific norms of trabecular-bone-score (TBS) and its associated factors. Here, we provide norms of TBS in Asian-Indians and its relationship with serum 25-hydroxyvitamin D [25(OH)D] and intact-parathyroid hormone (iPTH).

PARTICIPANTS AND MEASUREMENTS

TBS, bone-mineral-density (BMD), and vertebral-fractures (VFs) were assessed using dual-energy X-ray absorptiometry in 923 healthy Asian-Indians (aged 20-60 years). Serum 25(OH)D, iPTH, T4/TSH,, glycosylated-haemoglobin (HbA1c) were measured and associations with TBS assessed using multivariable linear regression. Subjects with BMD Z-score ≤ -2.0 or ≥2.0 at any sites, VFs, TSH > 10.0 or <0.05 µIU/ml, blood-glucose >11.1 mmol/L or HbA1c > 8.0% were excluded for generating Asian-Indian norms.

RESULTS

TBS norms were generated in 744 healthy Asian-Indians (M:F,389:385). The cut-offs generated for 'normal', 'partially-degraded', and 'degraded' TBS were >1.305, 1.204-1.305 and <1.204, respectively. Mean TBS was lower in females than males (p < .001). There was 75% congruency in TBS categories between Asian-Indian and existing norms. Specificity (97.8 vs. 77.9%, p < .001) and diagnostic-accuracy (97.8% vs. 78.4%, p < .001) of TBS to detect osteoporosis were higher with Asian-Indian norms. The sensitivity of 'partially-degraded' TBS to diagnose osteopenia was also higher with Asian-Indian norms. In multivariable regression, gender, body-mass-index (BMI), BMD-L1-L4, serum PTH, daily dietary-calorie intake and calcium intake were associated with TBS. Though 25(OH)D inversely correlated with PTH, 25(OH)D was not associated with TBS.

CONCLUSION

This study provides norms for TBS in Asian-Indians with gender-specific differences. Increasing age and higher BMI were associated with lower TBS. Associations of TBS with circulating PTH and/or 25(OH)D need confirmation in further studies.

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.

Covid-19 Susceptibility and Severity Might be Modified by Vitamin D Status: Theoretical and Practical Considerations

Background:

The recently identified SARS-CoV-2 coronavirus has resulted in the Covid-19 pandemic with severe morbidity and high mortality, particularly in certain sections of the population. The co-morbidity patterns associated with adverse outcomes are multiple and complex and there is emerging epidemiological, nutritional and molecular biological evidence that an inadequate vitamin D status is a contributing factor.

Objective:

The aim was to review the role of vitamin D in immune function with particular reference to the mechanisms whereby it supports immune efficiency, host protection and immune modulation. The evidence for the possible benefit of vitamin D supplementation to ameliorate the severity of respiratory infection by SARS-CoV-2 and other pathogens was also reviewed with a view to making a recommendation.

Methods:

PubMed, MEDLINE and Google Scholar were searched using the terms: Covid-19, coronavirus, SARS-CoV-2, vitamin D, calcitriol, deficiency, adaptive immunity, innate immunity, ventilation, critical care, intensive care, acute respiratory distress syndrome, cytokine storm, respiratory viruses, respiratory tract infection, respiratory syncytial virus, influenza, supplementation. Papers for inclusion were selected on the basis of relevance and quality.

Findings:

Vitamin D insufficiency is widespread in many parts of the world. Vitamin D is needed for normal protective and surveillance immune function and there is evidence that deficiency increases the risk of some respiratory infections, probably including Covid-19. By binding with dedicated receptors on immune cells vitamin D influences several strands of immune function, including the production of anti-microbial peptides and several cytokines that promote an appropriate immune response. Vitamin D supplementation probably reduces the risk of respiratory infection, with persuasive biological, epidemiological and observational evidence for possible benefit against Covid-19.

Conclusion:

Despite the lack of direct evidence specific to Covid-19 a cogent theoretical case can be made for giving adults from selected groups, and arguably all adults, routine supplementation with vitamin D to improve immune efficiency and reduce the incidence and severity of respiratory infections. This could be particularly important in sections of the population with a high prevalence of vitamin D insufficiency. Targeted research is required to provide firm evidence to guide practice.

Can Vitamins, as Epigenetic Modifiers, Enhance Immunity in COVID-19 Patients with Non-communicable Disease?

PURPOSE OF REVIEW

The highly infectious transmissible disease, the novel SARS-CoV-2, causing the coronavirus disease (COVID-19), has a median incubation time of 5 to 15 days. The symptoms vary from person to person and many are "hidden carriers." Few people experience immediate reaction and even death within 48 h of infection. However, many show mild to chronic symptoms and recover. Nevertheless, the death rate due to COVID-19 transmission is high especially among patients with non-communicable diseases. The purpose of this review is to provide evidence to consider vitamins as epigenetic modifiers to enhance immunity and reduce inflammatory response in COVID-19 patients with non-communicable diseases.

RECENT FINDINGS

Clinical evidence has suggested the risk of getting infected is high among individuals with non-communicable diseases such as cardiovascular disease, type-2 diabetes, cancer, acute respiratory distress syndrome, and renal disease, as well as the elderly with high mortality rate among the cohort. The impact is due to an already compromised immune system of patients. Every patient has a different response to COVID-19, which shows that the ability to combat the deadly virus varies individually. Thus, treatment can be personalized and adjusted to help protect and combat COVID-19 infections, especially in individuals with non-communicable diseases. Based on current published scientific and medical evidence, the suggestions made in this article for combination of vitamin therapy as epigenetic modifiers to control the unregulated inflammatory and cytokine marker expressions, further needs to be clinically proven. Future research and clinical trials can apply the suggestions given in this article to support metabolic activities in patients and enhance the immune response.

Vitamin D deficiency during pregnancy affects the function of Th1/Th2 cells and methylation of IFN-γ gene in offspring rats

The effects of maternal vitamin D status on offspring's Th1/Th2 cell function and the related mechanisms have not been reported. In this study, we established the rat model of vitamin D deficiency during pregnancy. 48 female Sprague-Dawley rats (8 weeks old) were randomly assigned to three groups (n = 16/group): control group (fed with standard AIN-93 G diet until parturition), vitamin D deficiency group (VDD group, fed with vitamin D deficient diet until parturition) and vitamin D supplementation group (VDS group, fed with vitamin D deficient diet prior to mating and with standard AIN-93 G diet during pregnancy). At 4 weeks of age, the ratio of T helper type 1/ T helper type 2 (Th1/Th2) cells and the levels of Th1/Th2 cytokines (IFN-γ, IL-4, IL-5, IL-6, IL-10 and IL-13) in offspring rats were determined by Flow Cytometry and Meso Scale Discovery, respectively. Furthermore, DNA methyltransferase (DNMT) activity as well as the methylation levels of IFN-γ and IL-4 genes were measured. As a result, rats in the VDD group showed a significant decrease in Th1/Th2 ratio and IFN-γ level and an increase in IL-4 level. Additionally, up-regulated DNMT activity and increased methylation rate of IFN-γ gene was shown in VDD offspring rats. Supplementation with vitamin D during pregnancy reversed the above abnormalities. In conclusion, maternal vitamin D deficiency affected the function of Th1/Th2 cells and methylation of IFN-γ gene in offspring rats. Meanwhile, maternal vitamin D deficiency had the potential to regulate DNMT activity, which may determine the status of methylation.

Effects of vitamin D supplements on frequency of CD4+ T-cell subsets in women with Hashimoto's thyroiditis: a double-blind placebo-controlled study

BACKGROUND

Vitamin D is a modulator of immune functions. Investigations on the mechanisms of vitamin D action and pathogenesis of Hashimoto's thyroiditis (HT) have revealed that vitamin D can reduce damages to thyroid cells caused by autoreactive immune cells.

METHODS

Totally, 48 female patients with HT disease were introduced to the study by endocrinologists. Patients were divided into two major groups of 24 individuals and treated weekly with 50,000 IU of cholecalciferol (vitamin D group) or placebo (placebo group) using oral administration for 3 months. Eventually, 17 of the 24 patients in each group finished the study. Before and after supplementation, frequencies of Th1, Th17, Th2 and Tr1 cells and mean fluorescent intensity (MFI) of the associated cytokines, including IFN-γ, IL-17, IL-4 and IL-10, were assessed using flow cytometry. Furthermore, gene expression of IL-10 was assessed using real-time PCR.

RESULTS

Results of this study showed that cholecalciferol supplementation caused a significant decrease in Th17/Tr1 ratio. The proportion and MFI of Th1, Th2, Tr1 and Th17 cells included no significant changes in vitamin D group, compared to those in placebo group. Expression rate and MFI of IL-10 increased in both groups. This increase was higher in vitamin D group than placebo group with no significance.

CONCLUSIONS

In this novel preliminary clinical trial study, supplementation with cholecalciferol in HT patients for 3 months changed the balance of CD4⁺ T-cell subsets to improve the disease control. However, further studies are necessary to investigate effects of vitamin D on immune functions in HT patients.

Cellular and molecular mechanisms of vitamin D in food allergy

Food allergies are becoming increasingly prevalent, especially in young children. Epidemiological evidence from the past decade suggests a role of vitamin D in food allergy pathogenesis. Links have been made between variations in sunlight exposure, latitude, birth season and vitamin D status with food allergy risk. Despite the heightened interest in vitamin D in food allergies, it remains unclear by which exact mechanism(s) it acts. An understanding of the roles vitamin D plays within the immune system at the cellular and genetic levels, as well as the interplay between the microbiome and vitamin D, will provide insight into the importance of the vitamin in food allergies. Here, we discuss the effect of vitamin D on immune cell maturation, differentiation and function; microbiome; genetic and epigenetic regulation (eg DNA methylation); and how these processes are implicated in food allergies.

The association of serum vitamin D concentration and ventricular dysfunction among patients with acute coronary syndrome

Objective

To determine if vitamin D deficiency was associated with higher odds of left ventricular dysfunction among patients with acute coronary syndrome (ACS) and, if so, to determine whether this association was mediated by increased inflammation as measured by C-reactive protein (CRP) and white blood cell count (WBC).

Methods

This was a cross-sectional study of 170 participants with ACS. Multiple logistic regression was used to examine the association between the outcome of ventricular performance and serum vitamin D concentrations. We also determined whether CRP and WBC meet standard criteria as the mediators between left ventricular ejection fraction and vitamin D deficiency.

Results

Participants with vitamin D deficiency were more likely to have ventricular dysfunction (OR: 2.12, 95% CI: 1.2–5.23). WBC counts did not meet one of the criteria for mediation. However, the WBC was an effect modifier such that the association of vitamin D deficiency and ventricular dysfunction was only present among participants with WBC more than 11,000.

Conclusion

This study found that vitamin D deficiency was associated with higher odds of ventricular dysfunction. Further longitudinal and experimental studies are necessary to confirm this finding and to determine if there is a role for vitamin D supplementation therapy in preventing ventricular dysfunction in select patient populations.

High-dose vitamin D3 supplementation decreases the number of colonic CD103+ dendritic cells in healthy subjects

PURPOSE

Vitamin D may induce tolerance in the intestinal immune system and has been shown to regulate the phenotype of tolerogenic intestinal dendritic cells (DCs) in vitro. It is unknown whether vitamin D supplementation affects human intestinal DCs in vivo, and we aimed to investigate the tolerability and effect on intestinal CD103⁺DCs of high-dose vitamin D₃ treatment in healthy subjects.

METHODS

Ten healthy subjects received a total of 480,000 IU oral vitamin D₃ over 15 days and colonic biopsies were obtained before and after intervention by endoscopy. Lamina propria mononuclear cells (LPMCs) were isolated from the biopsies, stained with DC surface markers and analysed with flow cytometry. Snap-frozen biopsies were analysed with qPCR for DC and regulatory T cell-related genes.

RESULTS

No hypercalcemia or other adverse events occurred in the test subjects. Vitamin D decreased the number of CD103⁺ DCs among LPMCs (p = 0.006). Furthermore, vitamin D induced mRNA expression of TGF-β (p = 0.048), TNF-α (p = 0.006) and PD-L1 (p = 0.02) and tended to induce IL-10 expression (p = 0.06). Multivariate factor analysis discriminated between pre- and post-vitamin D supplementation with a combined increased qPCR expression of PD1, PD-L1, TGF-β, IL-10, CD80, CD86, FOXP3, NFATc2 and cathelicidin.

CONCLUSION

High-dose vitamin D supplementation is well tolerated by healthy subjects and has a direct effect on the CD103⁺ DCs, local cytokine and surface marker mRNA expression in the colonic mucosa, suggestive of a shift towards a more tolerogenic milieu.

Oral spray wintertime vitamin D3 supplementation has no impact on inflammation in Gaelic footballers

Vitamin D inadequacy [total 25(OH)D <50 nmol/L] is widespread in athletes. The biologically active metabolite, 1,25-dihydroxyvitamin D, may be involved in regulating inflammation although in vitro findings have not been consistently replicated in human intervention trials. This study, conducted at a latitude of 55°N, aimed to assess inflammatory biomarkers in Gaelic footballers before and after a wintertime vitamin D₃ intervention. Samples from a 12-week double-blind, randomized, placebo-controlled trial, in which 42 Gaelic footballers received 3000 IU (75 μg) vitamin D₃ daily or placebo via oral spray solutions, were analysed for a range of inflammatory biomarkers. Cytokines (interleukin-8 and tumor necrosis factor-α), cathelicidin and high sensitivity C-reactive protein were quantified by multiplex assay, enzyme-linked immunosorbent assay and clinical biochemistry, respectively. White blood cell, lymphocyte, and neutrophil concentrations were determined by full blood profile. Data on total 25-hydroxyvitamin D, measured by LC-MS/MS, were available from the previous study. Vitamin D₃ supplementation significantly increased mean total 25-hydroxyvitamin D concentrations from 47 to 84 nmol/L (P = 0.006); yet this had no effect on white blood cell count (P = 0.699), lymphocyte (P = 0.694), neutrophil (P = 0.594), interleukin-8 (P = 0.334), tumor necrosis factor-α (P = 0.587), cathelicidin (P = 0.745) or high sensitivity C-reactive protein concentration (P = 0.621) compared to placebo. 12-weeks vitamin D₃ supplementation did not impact the immune profile of Gaelic footballers. This is likely because biomarkers were within their respective normal range or at a concentration similar to that of the general population at baseline. Future studies are encouraged to use inflammation as their primary outcome measure and recruit athletes at risk of compromised immunity.

Hypercalcemia, hypercalciuria, and kidney stones in long-term studies of vitamin D supplementation: a systematic review and meta-analysis

BACKGROUND

Vitamin D supplementation is increasingly being used in higher doses in randomized controlled trials (RCTs). However, adverse events from very large annual doses of vitamin D have been shown in 2 RCTs, whereas in a third RCT, low-dose vitamin D, with calcium supplements, was shown to increase kidney stone risk.

OBJECTIVE

We analyzed the side effects related to calcium metabolism in RCTs, specifically hypercalcemia, hypercalciuria, and kidney stones, in participants who were given vitamin D supplements for ≥24 wk compared with in subjects in the placebo arm.

DESIGN

The following 3 main online databases were searched: Ovid Medline (PubMed), EMBASE, and the Cochrane Library. Software was used for the meta-analysis.

RESULTS

A total of 48 studies with 19,833 participants were identified, which reported ≥1 of the following side effects: hypercalcemia, hypercalciuria, or kidney stones. Of these studies, kidney stones were reported in only 9 trials with a tendency for fewer subjects reporting stones in the vitamin D arm than in the placebo arm (RR: 0.66, 95% CI: 0.41, 1.09; P = 0.10). In 37 studies, hypercalcemia was shown with increased risk shown for the vitamin D group (RR: 1.54; 95% CI: 1.09, 2.18; P = 0.01). Similar increased risk of hypercalciuria was shown in 14 studies for the vitamin D group (RR: 1.64; 95% CI: 1.06, 2.53; P = 0.03). In subgroup analyses, it was shown that the effect of vitamin D supplementation on risk of hypercalcemia, hypercalciuria, or kidney stones was not modified by baseline 25-hydroxyvitamin D, vitamin D dose and duration, or calcium co-supplementation.

CONCLUSIONS

Long-term vitamin D supplementation resulted in increased risks of hypercalcemia and hypercalciuria, which were not dose related. However, vitamin D supplementation did not increase risk of kidney stones. Additional large RCTs of long-term vitamin D supplementation are required to confirm these findings.

Prenatal high-dose vitamin D3 supplementation has balanced effects on cord blood Th1 and Th2 responses

Background

Antenatal vitamin D₃ (vitD₃) supplementation significantly increases maternal and neonatal 25-hydroxyvitamin D₃ (25(OH)D₃) concentration, yet the effect of an improvement in maternal-fetal vitamin D status on the neonatal immune response is unclear.

Method

To assess the effect of prenatal vitD₃ supplementation on cord blood T cell function, healthy pregnant Bangladeshi women (n = 160) were randomized to receive either oral 35,000 IU/week vitD₃ or placebo from 26 to 29 weeks of gestation to delivery. In a subset of participants (n = 80), cord blood mononuclear cells (CBMC) were cultured, non-adherent lymphocytes were isolated to assess T cell cytokine responses to phytohemagglutinin (PHA) and anti-CD3/anti-CD28 (iCD3/iCD28), measured by multiplex assay. In 12 participants, lymphocyte gene expression profiles were analyzed by PCR array.

Result

In supplemented group, increased concentrations of IL-10 (P < 0.000) and TNF-α (P = 0.05) with iCD3/iCD28 stimulation and IFN-γ (p = 0.05) with PHA stimulation were obtained compared to placebo group. No differences in the gene expression profile were noted between the two groups. However, PHA stimulation significantly induced the expression of genes encoding Th1 and Th2 cytokines and down-regulated a number of genes involved in T-cell development, proliferation and differentiation of B cells, signal transduction pathway, transcriptional regulation and pattern recognition receptors (PRRs) in the vitamin D group (vitD group).

Conclusion

Third-trimester high-dose vitD₃ supplementation in healthy pregnant women had balanced effects on biomarkers of cord blood Th1 and Th2 responses.

Trial registration

ClinicalTrials.gov (NCT01126528).

Electronic supplementary material

The online version of this article (doi:10.1186/s12937-016-0194-5) contains supplementary material, which is available to authorized users.

Identification of reference housekeeping-genes for mRNA expression studies in patients with type 1 diabetes

Selection of appropriate housekeeping-genes as reference is important in mRNA expression-related experiments. It is more important in diabetes since hyperglycemia per se can influence expression of housekeeping-genes. RNA expression of Glyceraldehyde-3-phosphate-dehydrogenase, β-actin and 18S-ribosomal-RNA, Hypoxanthine-phosphoribosyl-transferase (HPRT), Tyrosine-3-monooxygenase/tryptophan (YHWAZ), β2-microglobin (β2M), TATA-binding-protein (TBP), and Ubiquitin C and cytochrome1 (CYC1) assessed in circulating-lymphocytes-(PBMC) of patients with type-1-diabetes and healthy controls. The stability ('M' value <1.02) and number of housekeeping-genes required for normalization in qRT-PCR were determined by 'ge-norm software.' Vitamin-D-receptor (VDR) was used as a target gene. All the nine genes tested had sufficient 'M' value in diabetes and healthy controls. However, housekeeping-genes indicated a relatively higher stability of expression in healthy controls in comparison to diabetes. Use of single housekeeping-genes brought gross variation in the calculation of VDR-mRNA copies. The ge-norm software suggested geometric mean of five housekeeping-genes for ideal normalization in diabetes (CYC1, β-actin, YHWAZ, HPRT, and β2M) and only three in controls (CYC1, β-actin, and TBP). HbA1c did not correlate with expression of any of the nine housekeeping-genes. Thus, geometric mean of CYC1, β-actin, YHWAZ, HPRT, and β2M needs to be used for ideal normalization of mRNA in type-1-diabetes. Similar studies are required in other population.

Circulating Cathelicidin Concentrations in a Cohort of Healthy Children: Influence of Age, Body Composition, Gender and Vitamin D Status

Cathelicidin is an antimicrobial peptide whose circulating levels are related to vitamin D status in adults. This study sought to determine if circulating cathelicidin concentrations in healthy children are related to the age of the child, body composition and vitamin D status at birth and at the time of the study visit. Blood samples were obtained during yearly visits from 133 children, ages 2–7, whose mothers had participated in a pregnancy vitamin D supplementation RCT. Radioimmunoassay and ELISA were performed to analyze 25(OH)D and cathelicidin, respectively. Statistical analyses compared cathelicidin concentrations with concentrations of 25(OH)D at various time points (maternal levels throughout pregnancy, at birth, and child’s current level); and with race/ethnicity, age, gender, BMI, percent fat, and frequency of infections using Student’s t-test, χ², Wilcoxon ranked-sum analysis, and multivariate regression. The cohort’s median cathelicidin concentration was 28.1 ng/mL (range: 5.6–3368.6) and did not correlate with 25(OH)D, but was positively correlated with advancing age (ρ = 0.236 & p = 0.005, respectively). Forty patients evaluated at two visits showed an increase of 24.0 ng/mL in cathelicidin from the first visit to the next (p<0.0001). Increased age and male gender were correlated with increased cathelicidin when controlling for race/ethnicity, percent fat, and child’s current 25(OH)D concentration (p = 0.028 & p = 0.047, respectively). This study demonstrated that as children age, the concentration of cathelicidin increases. Furthermore, male gender was significantly associated with increased cathelicidin concentrations. The lack of association between vitamin D status and cathelicidin in this study may be due to the narrow range in observed 25(OH)D values and warrants additional studies for further observation.

Essential vitamins for an effective T cell response

Effective adaptive immune responses rely upon appropriate activation of T cells by antigenic peptide-major histocompatibility complex on the surface of antigen presenting cells (APCs). Activation relies on additional signals including co-stimulatory molecules on the surface of the APCs that promote T cell expansion. The immune response is further sculpted by the cytokine environment. However, T cells also respond to other environmental signals including hormones, neurotransmitters, and vitamins. In this review, we summarize the mechanisms through which vitamins A and D impact immune responses, particularly in the context of T cell responses.

A randomized controlled trial on the effect of vitamin D3 on inflammation and cathelicidin gene expression in ulcerative colitis patients

BACKGROUND

Inflammatory bowel disease (IBD) is an intestinal chronic inflammatory condition and includes Crohn's disease (CD) and ulcerative colitis (UC). It has been proposed that Vitamin D supplementation may have a beneficial role in IBD.

AIM

To characterize the effects of Vitamin D on cathelicidin (hCAP/LL37) gene expression, ESR, and serum hs-CRP levels.

MATERIALS AND METHODS

Ninety UC patients on remission were randomized to receive 300,000 IU intramuscular Vitamin D or 1 mL normal saline as placebo, respectively. Before and 90 days after intervention, serum levels of 25 (OH)-Vitamin D3, PTH, Calcium, ESR, and hs-CRP were measured. Cathelicidin gene expression was also quantified using qRT-PCR.

RESULTS

Baseline serum 25-OH-Vitamin D3 levels were not different between the two groups and after intervention, increased only in Vitamin D group (P < 0.001). Hs-CRP levels were lower in Vitamin D group after intervention (Before: 3.43 ± 3.47 vs 3.86 ± 3.55 mg/L, P = 0.56; after: 2.31 ± 2.25 vs 3.90 ± 3.97 mg/L, P= 0.023). ESR decreased significantly in Vitamin D group (Before: 12.4 ± 6.1 vs 12.1 ± 5.3 mm/h, P= 0.77; after: 6.7 ± 4.5 vs 11.4 ± 5.5 mm/h, P< 0.001). The mean fold change in hCAP18 gene expression in Vitamin D group was significantly higher than placebo group. (Mean ± SD: 3.13 ± 2.56 vs 1.09 ± 0.56; median ± interquartile range: 2.17 ± 3.81 vs 0.87 ± 0.53, P< 0.001).

CONCLUSION

Decreases in ESR and hs-CRP levels and increase in LL37 gene expression support the hypothesis that Vitamin D supplementation may have a beneficial role in UC patients.

Calcitriol-modulated human antibiotics: New pathophysiological aspects of vitamin D

Traditionally, calcitriol has been considered a calcium and phosphate regulating hormone, but has recently been shown to play a pivotal role in innate immunity. Many barrier and immune cells have membrane and intracellular receptors that recognize different microbial antigens. Activation of these receptors induces synthesis of 1α-hydroxylase, which acts on 25 hydroxyvitamin D to generate intracellular calcitriol. Calcitriol activates its receptor and enhances the synthesis of important human antibiotics like cathelicidin and β2-defensin while inhibiting hepcidin. These pluripotent peptides have an important role in innate immunity, and their regulation is abnormal in hypovitaminosis D. The literature on their secretion mechanisms, levels in different organic fluids, mechanism of action, and relationship with vitamin D is reviewed here.

Vitamin D, serum 25(OH)D, LL-37 and polymorphisms in a Canadian First Nation population with endemic tuberculosis

BACKGROUND

Canadian First Nation populations have experienced endemic and epidemic tuberculosis (TB) for decades. Vitamin D-mediated induction of the host defence peptide LL-37 is known to enhance control of pathogens such as Mycobacterium tuberculosis.

OBJECTIVE

Evaluate associations between serum levels of 25-hydroxy vitamin D (25(OH)D) and LL-37, in adult Dene First Nation participants (N = 34) and assess correlations with single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP).

DESIGN

Venous blood was collected from all participants at baseline (winter and summer) and in conjunction with taking vitamin D supplements (1,000 IU/day) (winter and summer). Samples were analysed using ELISA for concentrations of vitamin D and LL-37, and SNPs in the VDR and VDBP regions were genotyped.

RESULTS

Circulating levels of 25(OH)D were not altered by vitamin D supplementation, but LL-37 levels were significantly decreased. VDBP and VDR SNPs did not correlate with serum concentrations of 25(OH)D, but LL-37 levels significantly decreased in individuals with VDBP D432E T/G and T/T, and with VDR SNP Bsm1 T/T genotypes.

CONCLUSIONS

Our findings suggest that vitamin D supplementation may not be beneficial as an intervention to boost innate immune resistance to M. tuberculosis in the Dene population.

Vitamin D for the prevention of cardiovascular disease: Are we ready for that?

A general concept of clinical benefit of vitamin D supplementation has emerged from the evidence in prevention of osteoporosis. From the cardiovascular point of view, clinical benefit of such supplementation remains less clear. Studies in vitro and in animal models demonstrated the expression of vitamin D receptors in endothelial cells, vascular smooth muscle and cardiomyocytes. Vitamin D has been directly implicated in endothelium-mediated vasodilation, anti-coagulant activity and inhibition of the inflammatory response. Indirectly, it may favor the reduction of blood pressure, myocardial hypertrophy and ventricular arrhythmias. In contrast to these mechanistic findings, cross-sectional, longitudinal and small clinical trials have not been consistent in demonstrating association between cardiovascular events and vitamin D. Besides, methodological issues in the tests for serum levels of vitamin D may also contribute to this puzzle. Hence, in the current state of knowledge, it may be too early to consider or to rule out vitamin D as a tool to either estimate or mitigate residual cardiovascular risk. In this review, we discuss recent advances and potential limitations in mechanistic and clinical evidences that are outlining the framework of interaction between vitamin D and cardiovascular risk.

Effect of Vitamin D3 Supplementation in Combination with Weight Loss on Inflammatory Biomarkers in Postmenopausal Women: A Randomized Controlled Trial

Obesity and vitamin D deficiency are associated with risk for several cancers, possibly through inflammation and adipokine-related pathways. Two hundred and eighteen postmenopausal women with BMI > 25 kg/m(2) and low serum 25-hydroxyvitamin D (25(OH)D; ≥10-<32 ng/mL), were randomized to 12 months of either (i) weight-loss intervention + 2000 IU/day oral vitamin D3 or (ii) weight-loss intervention + daily placebo. Serum adiponectin, leptin, TNFα, IL6, IL1β, IL8, and IL10, were measured by immunoassay, and a composite inflammatory biomarker score calculated. Using generalized estimating equations, mean changes in outcomes were compared between arms (intent-to-treat), adjusted for possible confounders. Analyses were also stratified by weight-loss (gained/no weight-loss; <5%; 5% to 10%; ≥10%). At 12 months, there were no significant differences in analyte changes between arms. In stratified analyses, participants randomized to vitamin D3 who lost 5% to 10% of baseline weight, versus participants who gained weight/had no weight-loss, had significantly greater decreases in levels of IL6 compared with those randomized to placebo: absolute change -0.75 pg/mL (-17.2%), placebo versus -1.77 pg/mL (-37.3%), vitamin D, P = 0.004. Similar but attenuated results were observed for participants who lost ≥10% of baseline weight: -0.41 pg/mL (-13.6%), placebo versus -0.67 pg/mL (-17.3%), vitamin D, P = 0.02. Effects of vitamin D3 supplementation on levels of IL1β were inconsistent when stratified by weight loss. There were no intervention effects on IL10, TNFα, IL8, the composite score, adiponectin, or leptin, when stratified by weight-loss. In conclusion, vitamin D3 supplementation in combination with weight-loss of at least 5% of baseline weight was associated with significant reductions in levels of IL6.

The immediate protective response to microbial challenge

The innate immune system detects infection and tissue injury through different families of pattern-recognition receptors (PRRs), such as Toll-like receptors. Most PRR-mediated responses initiate elaborate processes of signaling, transcription, translation, and secretion of effector mediators, which together require time to achieve. Therefore, PRR-mediated processes are not active in the early phases of infection. These considerations raise the question of how the host limits microbial replication and invasion during this critical period. Here, we examine the crucial defense mechanisms, such as antimicrobial peptides or extracellular traps, typically activated within minutes of the initial infection phase, which we term the "immediate protective response". Deficiencies in different components of the immediate protective response are often associated with severe and recurrent infectious diseases in humans, highlighting their physiologic importance.