Association of vitamin D receptor genetic variants with susceptibility to asthma and atopy

The Association of Vitamin D Receptor Gene Polymorphisms with Vitamin D, Total IgE, and Blood Eosinophils in Patients with Atopy

BACKGROUND

In order to improve the control of atopic diseases, it is important to clarify the pathogenesis of atopy and identify its various triggers. Single nucleotide polymorphisms (SNPs) of the vitamin D receptor gene (VDR) may impact atopy. The aim of this study was to investigate the possible associations between VDR SNPs and vitamin D, total IgE, and eosinophils in atopy.

METHODS

In total, 203 adults, including 122 patients with atopic diseases (45 with atopic dermatitis, 77 with allergic asthma) and 81 healthy controls, were involved in the study. The blood eosinophil count was determined with an automated hematology analyzer. Vitamin D and total immunoglobulin E (IgE) levels were evaluated using the ELISA method. Polymorphisms in the VDR gene were analyzed with real-time PCR using TaqMan probes.

RESULTS

We analyzed six VDR single nucleotide polymorphisms and found a significant association between VDR rs731236 GG genotype and normal vitamin D levels in atopic patients and healthy subjects (OR 11.33; 95% CI: 1.049-122.388 and OR 4.04; 95% CI: 1.117-14.588, respectively, p < 0.05). Additionally, the study results revealed a significant relationship between the VDR rs2228570 GG genotype and normal vitamin D levels in patients with atopy and healthy subjects (OR 3.80; 95% CI: 1.190-12.134 and OR 2.09; 95% CI: 1.044-4.194, respectively, p < 0.05). The rs2228570 allele A was associated with decreased vitamin D levels in patients with atopy and healthy subjects (OR 0.28; 95% CI: 0.098-0.804 and OR 0.229; 95% CI: 0.069-0.761, respectively, p < 0.05). The VDR rs3847987 genotypes AA and AC were significantly associated with normal vitamin D levels in healthy subjects (OR 35.99; 95% CI: 6.401-202.446 and OR 4.72; 95% CI: 1.489-15.007, respectively, p < 0.05). In addition, a decreased amount of vitamin D was associated with atopic diseases such as atopic dermatitis and allergic asthma (OR 0.49; 95% CI: 0.439-1.308 and OR 0.58; 95% CI: 0.372-0.908, respectively, p < 0.05). The rs11168293 allele T was associated with the normal range of total IgE in atopy (OR 2.366; 95% CI: 1.133-5.027; p < 0.05). Significant associations were found between VDR rs731263 allele G, rs11168293 allele G, and increased blood eosinophil levels in patients with atopy (OR 0.319; 95% CI: 0.163-0.934 and OR 0.323; 95% CI: 0.112-0.935, respectively, p < 0.05).

CONCLUSIONS

A decreased vitamin D level showed a significant relationship with atopic diseases (atopic dermatitis and allergic asthma). The association between the VDR gene polymorphisms rs2228570, rs731236, and rs11168293 and vitamin D, total IgE, and blood eosinophils in patients with atopy suggested that VDR polymorphisms and the vitamin D level should be considered when examining the factors associated with atopy.

Serum 25-hydroxyvitamin D, vitamin D receptor, and vitamin D binding protein concentrations in dogs with acute pancreatitis compared to healthy control dogs

BACKGROUND

Previous studies have documented vitamin D imbalance in dogs with acute pancreatitis (AP), but no studies have investigated serum vitamin D receptor (VDR) and vitamin D-binding protein (VDBP) concentrations.

OBJECTIVES

Compare serum 25-hydroxyvitamin D (25[OH]D), VDR, and VDBP concentrations in healthy dogs and dogs with AP and identify correlations between these concentrations with ionized calcium, C-reactive protein (CRP), and canine-specific pancreatic lipase (Spec cPL) concentrations.

ANIMALS

Twenty-two dogs with AP and 20 healthy control dogs.

METHODS

Prospective cross-sectional study. Serum 25(OH)D concentrations were measured using a chemiluminescence immunoassay, and VDR and VDBP concentrations were measured using a ELISA kit designed for dogs.

RESULTS

Serum concentrations of 25(OH)D were lower in dogs with AP (mean ± SD, 66.1 ± 39.2 ng/mL) than in controls (96.8 ± 30.4 ng/mL; P = .01), and VDR concentrations were lower in dogs with AP (5.3 ± 3.5 ng/mL) than in controls (7.4 ± 2.5 ng/mL; P = .03). No difference was observed in serum VDBP concentrations between the groups. Serum VDR concentrations differed between survivors (median [interquartile range] = 6.6 [4.3-8.2] ng/mL) and nonsurvivors (2.7 [0.5-3.5] ng/mL; P = .01). Negative correlations were observed among serum VDR, CRP (rs  = -0.55), and Spec cPL (rs  = -0.47) concentrations in dogs with AP.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with AP had lower serum 25(OH)D and VDR concentrations than controls. Additionally, our study suggests a potential role of VDR expression in the inflammatory process of AP in dogs.

Association Between VDR and CYP24A1 Polymorphisms, Atopic Dermatitis, and Biochemical Lipid and Vitamin D Profiles in Spanish Population: Case-Control Study

BACKGROUND

Atopic dermatitis (AD) is the most prevalent inflammatory skin disorder, characterized by impaired epidermal barrier function and an altered immune response, both of which are influenced by vitamin D deficiency. Single-nucleotide polymorphisms (SNPs) in VDR and CYP24A1 have been previously associated with AD.

OBJECTIVE

We sought to characterize the associations between the VDR and CYP24A1 polymorphisms and the vitamin D and lipid biochemical profile in children diagnosed with AD.

METHODS

A total of 246 participants (143 patients with AD and 103 healthy controls) were enrolled in this study. Genotyping for polymorphisms in VDR (rs2239185, rs1544410, rs7975232, rs2238136, rs3782905, rs2239179, rs1540339, rs2107301, rs2239182, and rs731236) and CYP24A1 (rs2248359 and rs2296241) was performed by allele-specific polymerase chain reaction using integrated fluidic circuit technology. Serum levels of calcium, phosphorus, and vitamin D were measured, and the biochemical lipid profile was determined.

RESULTS

Among VDR SNPs, rs2239182 exerted a protective effect against the development of AD, whereas rs2238136 was identified as a risk factor for AD. The GCC haplotype (rs2239185-G, rs1540339-C, and rs2238136-C) appeared to protect against the development of AD. rs2239182-CC was associated with higher 25(OH)D concentrations, whereas rs2238136-TT, rs2239185-GA, and rs2248359-TT were present in a large proportion of patients with serum vitamin D deficiency. rs2239185-AA, rs2239182-CC, and rs1540339-CC were associated with higher serum total cholesterol; rs2239182-TT was associated with lower low-density lipoprotein cholesterol; and rs2239182-TC with lower high-density lipoprotein cholesterol. Both CYP24A1 SNPs (rs2296241-AA and rs2248359-TT) were associated with higher high-density lipoprotein cholesterol levels.

CONCLUSIONS

The VDR SNP rs2238136 is a risk factor for AD and other SNPs in VDR and CYP24A1, which may lead to alterations in biochemical parameters that influence the risk of AD. Our findings highlight the complex genetic basis to AD and indicate that interrelationships between different genetic factors can lead to alterations in vitamin D metabolism or lipid profiles, which in turn may influence the development of AD.

Pregnancy and COVID-19: The Possible Contribution of Vitamin D

Background: Vitamin D deficiency has been associated with the severity of COVID-19. The role of vitamin D in pregnant women with COVID-19 has been poorly investigated to date. The aim of this study was to evaluate the influence of vitamin D in affecting some clinical features in pregnancy between SARS-CoV-2 positive and negative patients. Methods: Vitamin D pathway related polymorphisms and 25-hydroxyvitamin D levels were quantified in pregnant women followed from the first to the third trimester of pregnancy. Vitamin D deficiency was considered with values ≤ 30 ng/mL. Results: In total, 160 women were enrolled: 23 resulted positive for at least one SARS-CoV-2 related test (molecular swab or antibody tests). Vitamin D-associated polymorphisms were able to affect vitamin D levels in SARS-CoV-2 negative and positive subjects: remarkably, all the VDR TaqICC genotype patients were negative for SARS-CoV-2. In a sub-population (118 patients), vitamin D levels correlated with pregnancy-related factors, such as alpha-fetoprotein levels. Third-trimester vitamin D levels were lower in preterm births compared to full-term pregnancy: this trend was highlighted for SARS-CoV-2 positive patients. Conclusions: This is the first study demonstrating a role of vitamin D in affecting the clinical characteristics of pregnant women during the COVID-19 era. Further studies in larger and different cohorts of patients are required to confirm these findings.

Pre- and Postnatal Vitamin D Status and Allergy Outcomes in Early Childhood

The dramatic increase in the prevalence of allergic disease in recent decades reflects environmental and behavioural changes that have altered patterns of early immune development. The very early onset of allergic diseases points to the specific vulnerability of the developing immune system to environmental changes and the development of primary intervention strategies is crucial to address this unparalleled burden. Vitamin D is known to have immunomodulatory functions. While allergic disease is multifactorial, associations with reduced sunlight exposure have led to the hypothesis that suboptimal vitamin D levels during critical early periods may be one possible explanation. Interventions to improve vitamin D status, especially in early life, may be the key to allergic disease prevention.

Vitamin D Regulates the Expression of Glucocorticoid Receptors in Blood of Severe Asthmatic Patients

Purpose

Vitamin D (VitD) deficiency is a significant public health concern in many areas around the globe and has been associated with many immune-mediated diseases, including asthma. Severe asthma has been linked to a decreased glucocorticoid receptor (GR) ratio (GR-α/GR-β ratio), indicating steroid hyporesponsiveness. Using a combination of in silico and in vivo approaches, we aimed to explore the immunomodulatory effect of VitD on asthmatic patients diagnosed with hypovitaminosis D.

Methods

In silico tools were used to identify the regulatory effect of VitD supplementation on GR genes. We measured the expression levels of GR-α and the inactive isoform, GR-β, in the blood of adult asthmatics diagnosed with hypovitaminosis D before and after VitD supplementation. Moreover, the blood levels of inflammatory cytokines associated with asthma severity were determined.

Results

Using an in silico approach, we identified specific genes commonly targeted by VitD as well as corticosteroids, the mainstay of asthma therapy. NR3C1 gene encoding GR was found to be significantly upregulated on Th2 CD4 cells and NK cells. Interestingly, blood expression level of NR3C1 was lower in severe asthmatics compared to nonsevere asthmatics and healthy controls, while the blood level of VitD receptor (VDR) was higher. Upon VitD supplementation of severe asthmatic patients, there was a significant increase in the blood levels of GR-α with no change in GR-β mRNA expression. VitD supplementation also suppressed the blood levels of IL-17F and IL-4.

Conclusion

VitD may enhance steroid responsiveness by upregulating the expression of steroid receptor GR-α.

Impact of Maternal Vitamin D Status on the Formation of Atopic Dermatitis in Young Children

Recent studies have highlighted relationship of allergic diseases with vitamin D deficiency. The aim of the study was to evaluate the impact of maternal vitamin D levels in pregnancy on the formation of atopic dermatitis in early life. A total of 186 pregnant women and their infants who developed atopic dermatitis before the age of 2 years were involved in the prospective study. Most pregnant women (57.5%) were diagnosed with 25(OH)D deficiency (3.6 ± 4.4 ng/ml) (P = .000). Maternal 25(OH)D deficiency was directly related to atopic family anamnesis and relatively high IgE levels. In these cases, children developed atopic dermatitis before the age of 6 months (70.8%) with prevalence of moderate-severity (55%) and persistent course (68.3%) of the disease. The above mentioned supported the idea that the peculiarities of the formation of atopic dermatitis in young children are associated with low concentrations of vitamin D in mothers during pregnancy.

High-dose vitamin D during pregnancy and pathway gene polymorphisms in prevention of offspring persistent wheeze

BACKGROUND

Randomized controlled trials (RCTs) suggest a protective effect of high-dose vitamin D supplementation in pregnancy on offspring risk of persistent wheeze, but only in some individuals, which might be explained by variations in vitamin D pathway genes. This study aimed to investigate the effect of vitamin D supplementation by maternal and offspring vitamin D receptor (VDR) genotype and GC genotype, encoding vitamin D binding protein (VDBP), in two RCTs.

METHODS

In the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC₂₀₁₀ ) RCT, we analyzed the effect of high-dose vitamin D during pregnancy on the risk of persistent wheeze age 0-3 years by variants in single nucleotide polymorphisms (SNPs) in VDR (rs1544410, rs2228570, rs7975128, rs7975232) and GC (rs4588, rs7041). Replication was sought in the Vitamin D Antenatal Asthma Reduction Trial (VDAART).

RESULTS

In COPSAC₂₀₁₀ , VDR SNP rs1544410 influenced the effect of high-dose vitamin D: maternal P_interaction  = .049 and child P_interaction  = .001, with the largest effect in offspring from mothers with TT genotype: hazard ratio (95% CI), 0.26 (0.10-0.68), P = .006, and no effect among CT or CC genotypes: 0.85 (0.48-1.51), P = .58 and 0.94 (0.47-1.89), P = .87, respectively. However, these findings were not replicated in VDAART. There was no significant effect modification from maternal or offspring GC genotype in either COPSAC₂₀₁₀ or VDAART: all P_interaction  ≥ .17.

CONCLUSIONS

We found that the effect of high-dose vitamin D supplementation during pregnancy on offspring risk of persistent wheeze was significantly influenced by VDR genotype in the COPSAC₂₀₁₀ RCT, but not VDAART, which may be due to population differences.

Non-Musculoskeletal Benefits of Vitamin D beyond the Musculoskeletal System

Vitamin D, a fat-soluble prohormone, is endogenously synthesized in response to sunlight or taken from dietary supplements. Since vitamin D receptors are present in most tissues and cells in the body, the mounting understanding of the role of vitamin D in humans indicates that it does not only play an important role in the musculoskeletal system, but has beneficial effects elsewhere as well. This review summarizes the metabolism of vitamin D, the research regarding the possible risk factors leading to vitamin D deficiency, and the relationships between vitamin D deficiency and numerous illnesses, including rickets, osteoporosis and osteomalacia, muscle weakness and falls, autoimmune disorders, infectious diseases, cardiovascular diseases (CVDs), cancers, and neurological disorders. The system-wide effects of vitamin D and the mechanisms of the diseases are also discussed. Although accumulating evidence supports associations of vitamin D deficiency with physical and mental disorders and beneficial effects of vitamin D with health maintenance and disease prevention, there continue to be controversies over the beneficial effects of vitamin D. Thus, more well-designed and statistically powered trials are required to enable the assessment of vitamin D’s role in optimizing health and preventing disease.

Vitamin D3 receptor polymorphisms regulate T cells and T cell-dependent inflammatory diseases

It has proven difficult to identify the underlying genes in complex autoimmune diseases. Here, we use forward genetics to identify polymorphisms in the vitamin D receptor gene (Vdr) promoter, controlling Vdr expression and T cell activation. We isolated these polymorphisms in a congenic mouse line, allowing us to study the immunomodulatory properties of VDR in a physiological context. Congenic mice overexpressed VDR selectively in T cells, and thus did not suffer from calcemic effects. VDR overexpression resulted in an enhanced antigen-specific T cell response and more severe autoimmune phenotypes. In contrast, vitamin D3-deficiency inhibited T cell responses and protected mice from developing autoimmune arthritis. Our observations are likely translatable to humans, as Vdr is overexpressed in rheumatic joints. Genetic control of VDR availability codetermines the proinflammatory behavior of T cells, suggesting that increased presence of VDR at the site of inflammation might limit the antiinflammatory properties of its ligand.

Association of vitamin D gene polymorphisms in children with asthma - A systematic review

INTRODUCTION

The association of Vitamin D and children with asthma is known and there are several individual studies on Vitamin D polymorphisms. However, systematic reviews on all vitamin D associated gene polymorphisms have not been done in children with asthma.

OBJECTIVE

To investigate the association of Vitamin D associated gene polymorphisms and asthma in children (0-18 years) by systematic review and meta-analytic approach.

METHODS

Our search included 20 full text articles of which 15 were case control studies and 5 used family based linkage disequilibrium method. Total of 2491cases and 3682 controls were included in case control studies, with mean age of 9.58 years and 10.16 years respectively. Quantitative and qualitative analysis were done.

RESULTS

Quantitative analysis revealed significant association with protective effect of Apa1 polymorphism in allele (OR 0.81 (0.71,0.91) and homozygous major form (OR 0.83 (0.70,0.98) and Taq 1 minor allele in homozygous form (OR 0.73 (0.58,0.92) in children with asthma. However, the minor allele of Apa1(OR 1.21 (1.07,1.37), Bsm 1 in heterozygous (OR 1.35 (1.07,1.71) and homozygous minor form (OR 1.95 (1.59,2.39), major allele of Fok1(OR1.34 (1.17,1.52) and Taq1 (OR 1.22 (1.08,1.38) were found to be increasing the odds of asthma. Ethnic variations were noted in subgroup analysis. Qualitative analysis of the polymorphisms of the Vitamin D associated metabolic genes also showed significant associations.

CONCLUSION

Our review shows significant associations with VDR polymorphisms - Apa1, Bsm1, Fok 1, Taq 1, polymorphisms of Vitamin D metabolic genes - CYP27A1, CYP 2R1, CYP 24A1, GC and genes related to Vitamin D response element (VDRE) in children with asthma. Conducting large studies involving various ethnic regions will strengthen our knowledge on the association and aid in targeted interventions for control of asthma in children.

Genetic polymorphisms in vitamin D pathway influence 25(OH)D levels and are associated with atopy and asthma

Background

Vitamin D deficiency or insufficiency, has been associated with atopy and lack of asthma control. Our objective was to investigate associations between variants in genes of vitamin D pathway with serum levels of 25-hydroxyvitamin D (25(OH)D), atopy, asthma and asthma severity in teenagers from Northeast Brazil.

Methods

This is a cross sectional study nested in a cohort population of asthma. 25(OH)D was quantified from 968 of 11–17 years old individuals by ELISA. Asthma diagnosis was obtained by using the ISAAC Phase III questionnaire. Specific IgE was determined by ImmunoCAP; genotyping was performed using the 2.5 HumanOmni Biochip from Illumina. Statistical analyses were performed in PLINK 1.07 and SPSS 22.1.

Results

After quality control, 104 Single Nucleotides Variants (SNVs) in vitamin D pathway genes, typed in 792 individuals, were included in the analysis. The allele A of rs10875694 on VDR was positively associated with atopy (OR = 1.35; 95% CI 1.01–1.81). The allele C of rs9279 on VDR, was negatively associated with asthma risk (OR = 0.66; 95% CI 0.45–0.97), vitamin D insufficiency (OR = 0.78; 95% CI 0.70–0.96) and higher VDR expression. Two variants in VDR were associated with asthma severity, the allele A of rs2189480 (OR = 0.34; 95% CI 0.13–0.89) and the allele G of rs4328262 (OR = 3.18; 95% CI 1.09–9.28). The combination of variants in CYP2R1 and CYP24A1 (GAC, to rs10500804, rs12794714 and rs3886163, respectively) was negatively associated with vitamin D production (β = − 1.24; 95% CI − 2.42 to − 0.06).

Conclusions

Genetic variants in the vitamin D pathway affect vitamin D serum levels and, thus, atopy and asthma.

Vitamin D receptor polymorphisms are associated with severity of wheezing illnesses and asthma exacerbations in children

Single nucleotide polymorphisms (SNPs) of the vitamin D receptor (VDR) gene have shown linkage and association with asthma development in multiple cohort studies. However, the majority of investigations have focused on asthma phenotypes in cohorts with stable disease. We investigated the relationship between VDR SNPs and the frequency and severity of acute episodes of wheeze/asthma in a cohort of Australian children, as the ability to identify children at risk of more severe exacerbations could lead to personalized and improved genotype-specific treatment pathways. We successfully genotyped five SNPs of the VDR gene (rs2525046, rs9729, rs1544410 (BsmI), rs22239179, and rs2228570 (FokI)) in 657 children presenting to a tertiary children's hospital with acute asthma, bronchiolitis, or a wheezing illness. The relationships between VDR SNPs and exacerbation severity scores, β₂-agonist use, and frequency of respiratory exacerbations were analysed using multiple regression. The rs2525046 (FokI) CT genotype was associated with higher VDR mRNA intensity levels (p = 0.007) compared to the CC genotype. A trend towards significance (p=0.056) was identified between the rs2525046 TT genotype and higher VDR mRNA intensity levels compared to the CC genotype. Children with rs2228570 AA genotype had higher exacerbation severity scores (p=0.001) and poorer β₂-agonist treatment response (doses at 6 h: p = 0.009 and 12 h: p=0.033) compared to those with the GG genotype. Children with rs1544410 (BsmI) TT genotype had lower exacerbation severity scores (p = 0.005) compared to those with the CC genotype. Children with rs2228570 GA genotype presented to and/or were admitted to hospital more times since birth with respiratory (p = 0.011) and wheezing (p = 0.021) illnesses than children with the GG genotype. No associations were identified between rs9729, rs2525046 and r2239179 polymorphisms and acute wheezing/asthma variables. These findings suggest that genetic variants at the VDR locus may play a role in acute wheeze/asthma severity in children.

The role of oral vitamin D3 supplementation in the treatment of Chronic Rhinosinusitis in adults with Vitamin D deficiency

Background:

Chronic Rhinosinusitis (CRS) is a chronic inflammatory disorder of the mucosal lining of the nose and paranasal sinuses. The ability of Vitamin D (VD3) to augment innate and adaptive immune responses has sparked interest in its immunologic role in the treatment of CRS. In this study, the incidence of vitamin D deficiency in CRS patients was compared to normal population and the beneficial role of Vitamin D supplementation in its treatment was also evaluated.

Materials and Methods:

It is a retrospective 1-year study of 200 CRS patients with Vitamin D deficiency. The patients were divided into two groups, i.e. 100 patients were given oral Vitamin D supplements and the other group of 100 patients were treated as placebo. Both Vitamin D levels and the Total Nasal Symptom Score (TNSS) were assessed at the start and end of the study period.

Results:

Of the 200 subjects with CRS, 100 were given oral vitamin D supplementation in the form of Cholecalciferol 60000IU weekly once for 3 months and the other group were treated with placebo. Before the treatment, the average level of serum Vitamin D was 12.31 ng/ml. After 3 months, it increased significantly to 29.71 ng/ml. Similarly, the pretreatment TNSS score was on average 11.92. After 3 months, the scores fell by an average of 10.65 points, a significant statistical difference (P < 0.05).

Conclusion:

There is a higher prevalence of vitamin D deficiency in CRS patients and that vitamin D supplementation in these patients went a long way in alleviating their symptoms.

Analysis of 25-hydroxy cholecalciferol, immunoglobulin E, and vitamin D receptor single nucleotide polymorphisms (Apa1, Taq1, and Bsm1), among sample of Egyptian children with bronchial asthma: A case-control study

PURPOSE

The current study aimed to assess the serum levels of vitamin D and immunoglobulin E (IgE) among asthmatic Egyptian children and to find out the possible associations of vitamin D receptor (VDR) polymorphisms with bronchial asthma development.

METHODS

The study included 100 Egyptian children, 50 asthmatic children who were comparable with 50 age, sex, and body mass index-matched, unrelated healthy controls (HCs) clinical assessments of asthmatic children were done using global initiative of asthma. Pulmonary function tests (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], FEV1/FVC ratio) were performed. Enzyme-linked immunosorbent assays of serum vitamin D3 and total IgE were done. VDR-single nucleotide polymorphisms (SNPs) (ApaI, TaqI, and BsmI) detection has performed using polymerase chain reaction through restriction fragment length polymorphism technique. Data analysis was performed using SPSS version 20.0. The studied SNPs were followed the Hardy Weinberg equation.

RESULTS

The mean serum level of 25(OH) D3 was significantly lower among asthmatic children (13.46 ng/mL ± 10.50 SD) in comparison to HCs (37.53 ng/mL ± 13. 0.40 SD), P < .05. Vitamin D deficiency was detected in 72% of cases with no significant difference in its level regarding asthma control. There was significantly higher IgE level among asthmatic children (99.83 ku/L ± 233.81 SD) versus HCs (7.52 ku/L ± 3.32 SD), P < .05. Asthmatic children were presented more commonly with TaqI t allele (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.28-3.96; P < .05) and BsmI b allele (OR, 1.83; 95% CI, 1.05-3.21; P < .05). ApaI a allele was not significantly different among patients versus controls (P > .05). TT + Tt and Bb + bb genotypes were significantly higher among cases versus the controls, P < .05 for all.

CONCLUSIONS

TaqI and BsmI were associated with risk of bronchial asthma development among Egyptian children. High IgE and Low vitamin D status were frequently occurring among asthmatic children.

Association of vitamin D genetic pathway with asthma susceptibility in the Kurdish population

BACKGROUND

Vitamin D (Vit D) function in asthma progression has been studied well. The effects of genetic variations in Vit D pathway molecules have been also studied, although the results are contradicted. In the present study, for the first time we examined the Vit D pathway molecules included serum Vit D and vitamin D-binding protein (VDBP) and also genetic variations in the vitamin D receptor (VDR) and VDBP in a Kurdish population with asthma.

METHODS

An enzyme-linked immunosorbent assay (ELISA) method was used to measure the serum Vit D and VDBP. VDR rs1544410 and rs2228570 and VDBP rs7041 were assessed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The serum level of Vit D significantly decreased in asthmatic patients versus controls (16.26 ± 6.76 vs 23.05 ± 10.57 ng/mL, P value = .001). We observed an indirect correlation between Vit D and clinical findings. We also found an increased level of serum VDBP in patients as compared to the controls (1044.6 ± 310.82 vs 545.95 ± 121.73 µg/mL, P value < .0001). Besides, the risk of asthma progression was increased in patients with the VDR rs2228570 CC and VDBP rs7041 GG genotypes (OR = 3.56, P = .0382 and OR = 2.58, P = .01, respectively).

CONCLUSION

In summary, our results explain the influence of the genetic variations in VDR and VDBP in addition to Vit D and VDBP serum concentrations on asthma susceptibility in the Kurdish population.

Influence of vitamin D receptor gene FokI and ApaI polymorphisms on glucocorticoid response in patients with asthma

BACKGROUND

Glucocorticoid (GC)-resistant asthma, a complex disease phenotype, has a high morbidity and mortality and takes up a disproportionate share of healthcare costs. The aim of this work was to assess serum 25-hydroxyvitamin D (25(OH)VD) levels in steroid-resistant, steroid-sensitive patients with asthma and in healthy controls, and to investigate the association between the vitamin D receptor gene (VDR) FokI and ApaI polymorphisms and GC resistance in patients with asthma.

METHODS

This case-control study included 70 patients with severe bronchial asthma and 30 apparently healthy controls. Atopic status was determined by skin-prick test reaction to the most common locally-encountered allergens. A GC reversibility test was performed to differentiate between GC-sensitive and GC-resistant asthma. For all subjects, analysis of the VDR FokI and ApaI polymorphisms by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and measurement of serum 25(OH)VD levels by enzyme-linked immunosorbent assay (ELISA) were performed.

RESULTS

The frequencies of FokI polymorphism genotypes and alleles differed significantly between patients with asthma and controls. The frequencies of the TT genotype and T allele carriers were significantly higher among patients with asthma than among controls, and also among GC-resistant patients with asthma than among GC-sensitive patients with asthma. Additionally, serum 25(OH)VD levels differed significantly among the 3 VDR FokI polymorphic genotypes in GC-resistant patients with asthma; the highest level was detected in the TT genotype. No significant differences in ApaI were found.

CONCLUSION

We found a possible association between the FokI T allele and GC resistance in patients with asthma. Variations in VDR FokI might also play a role in 25(OH)VD levels.

Vitamin D plasma concentration and vitamin D receptor genetic variants confer risk of asthma: A comparison study of Taiwanese and Mongolian populations

Background

Recent reports have suggested that lower vitamin D serum levels are associated with susceptibility to and severity of asthma in different white populations, which may be due to a lack of sunlight exposure, genetic polymorphism of vitamin D pathway genes, and dietary intake. We investigated the associations between vitamin D concentration, genetic polymorphism of the vitamin D receptor (VDR), and asthma traits in Mongolian and Taiwanese populations that inhabited two different geographical areas.

Methods

In total, 328 Han Taiwanese subjects and 381 Mongolian subjects were enrolled, and their vitamin D serum levels assayed. Genomic DNA of 178 Han Taiwanese subjects and 90 Mongolian subjects was obtained from blood samples. Single-nucleotide polymorphisms (SNPs) of VDR, ApaI (rs7975232), TaqI (rs731236), BsmI (rs1544410) and FokI (rs2228570), were selected for genotyping. Logistic regression analyses were performed to detect an association between allergic asthma status and the interaction of the VDR SNP and serum vitamin D concentration in the case–control samples.

Results

We observed a significantly lower vitamin D level in the Mongolian subjects as compared with the Taiwanese population. In particular, in the population under 14 years of age, the serum vitamin D level was significantly higher in the Taiwanese population, in both non-asthmatic and asthmatic subjects, than in the Mongolian non-asthmatic and asthmatic subjects, respectively (P < 0.01). Moreover, the vitamin D level in the asthmatic children was significantly lower than that in the non-asthmatic children in both the Taiwanese and Mongolian populations (P < 0.01, respectively). Furthermore, we found that the rs2228570 genotype (OR, 3.763) of the VDR SNP and the vitamin D concentration (lower than 40 ng/ml, OR: 38.938) both contribute to increased susceptibility to bronchial asthma.

Conclusion

Our results demonstrated an association between vitamin D concentration and the risk of asthma in two populations of differing ethnicity living in different geographical areas. This information implies a potential role of vitamin D in the prevention and treatment of asthma worldwide.

Identification of Novel Biomarkers for Drug Hypersensitivity After Sequencing of the Promoter Area in 16 Genes of the Vitamin D Pathway and the High-Affinity IgE Receptor

The prevalence of allergic diseases and drug hypersensitivity reactions (DHRs) during recent years is increasing. Both, allergic diseases and DHRs seem to be related to an interplay between environmental factors and genetic susceptibility. In recent years, a large effort in the elucidation of the genetic mechanisms involved in these disorders has been made, mostly based on case-control studies, and typically focusing on isolated SNPs. These studies provide a limited amount of information, which now can be greatly expanded by the complete coverage that Next Generation Sequencing techniques offer. In this study, we analyzed the promoters of sixteen genes related to the Vitamin D pathway and the high-affinity IgE receptor, including FCER1A, MS4A2, FCER1G, VDR, GC, CYP2R1, CYP27A1, CYP27B1, CYP24A1, RXRA, RXRB, RXRG, IL4, IL4R, IL13, and IL13RA1. The study group was composed of patients with allergic rhinitis plus asthma (AR+A), patients with hypersensitivity to beta-lactams (BLs), to NSAIDs including selective hypersensitivity (SH) and cross-reactivity (CR), and healthy controls without antecedents of atopy or adverse drug reactions. We identified 148 gene variations, 43 of which were novel. Multinomial analyses revealed that three SNPs corresponding to the genes FCER1G (rs36233990 and rs2070901), and GC (rs3733359), displayed significant associations and, therefore, were selected for a combined dataset study in a cohort of 2,476 individuals. The strongest association was found with the promoter FCER1G rs36233990 SNP that alters a transcription factor binding site. This SNP was over-represented among AR+A patients and among patients with IgE-mediated diseases, as compared with control individuals or with the rest of patients in this study. Classification models based on the above-mentioned SNPs were able to predict correct clinical group allocations in patients with DHRs, and patients with IgE-mediated DHRs. Our findings reveal gene promoter SNPs that are significant predictors of drug hypersensitivity, thus reinforcing the hypothesis of a genetic predisposition for these diseases.

The Vitamin D Receptor Gene Polymorphisms in Asthmatic Children: A Case-Control Study

Background: The association between vitamin D receptor (VDR) polymorphisms and the risk of asthma remains unclear. This study aimed to investigate the effect of VDR gene polymorphisms and VDR mRNA expression levels on respiratory function, nitric oxide levels in expiratory air, and serum vitamin D levels in children with asthma. Materials and Methods: The study included 80 healthy children (control group) and 100 asthmatic children (asthma group) between the age of 5 and 18 years. The VDR genotypes (ApaI, TaqI, and FokI) and VDR mRNA levels were determined in all groups. Results: There was no statistically significant difference in vitamin D levels between the asthma group and the control group (P > 0.05). A significant association was found between both genotype (CC) of the TaqI polymorphism [odds ratio (OR) = 0.2, 95% confidence interval (CI) (0.07-0.5), P = 0.003] and genotype (CA) of ApaI polymorphisms [OR = 0.2, 95% CI (0.07-0.8), P = 0.02], and asthma risk. In addition, when single-nucleotide polymorphism allelic frequencies between asthma and control groups were compared there is no significant association (P > 0.05). When compared to control group, VDR mRNA expression in asthma group decreased in genotypes CC and CA of ApaI and in genotypes TT and TC of TaqI (P < 0.05). Conclusion: The results provide supporting evidence for an association between TaqI and ApaI polymorphisms and asthma susceptibility.

Effects of genetic polymorphisms in Vitamin D metabolic pathway on Vitamin D level and asthma control in South Indian patients with bronchial asthma

Objectives:

The study was designed to evaluate the single-nucleotide polymorphisms (SNPs) of genes involved in Vitamin D actions (rs2228570) and metabolic pathways (rs2248137 and rs10766197) and their associations with serum 25-hydroxy Vitamin D (25(OH)D) level and asthma control in South Indian patients with bronchial asthma.

Materials and Methods:

One hundred and two patients of South Indian origin with bronchial asthma either naive to inhaled corticosteroids (ICSs) or not receiving ICS for ≥1 month were included and were treated with ICS (beclomethasone 200 μg twice daily) for 8 weeks. One hundred and one unrelated healthy South Indians were used as controls. Pulmonary function test and fractional exhaled nitric oxide were used to assess asthma control. Serum 25(OH)D levels (chemiluminescence immunoassay) and SNPs in Vitamin D pathway (real-time polymerase chain reaction) were assessed. The associations of SNPs and serum 25(OH)D with asthma control was determined using linear regression. All analyses were performed using SPSS (version 19) and “SNPStats.” P < 0.05 was considered as statistically significant.

Results:

Vitamin D receptor (VDR) polymorphism (rs2228570) was found to be protective against asthma (P = 0.022), while there were no significant associations between the other two SNPs and asthma. Similarly, poor correlation and insignificant associations between the SNPs and serum 25(OH)D levels were observed in both cases and controls. There were also insignificant associations between the SNPs and asthma control.

Conclusion:

VDR polymorphism (rs2228570) was found to be protective against asthma in South Indians, while other genes involved in the metabolic pathway of Vitamin D did not show associations with asthma.

Genetic polymorphisms of pharmacogenomic VIP variants in the Lisu population of southwestern China: A cohort study

Pharmacogenomic studies of different ethnic or racial groups have been used to develop personalized therapies specific to subjects. This study aimed to identify the distribution differences of very important pharmacogenetic (VIP) variants between the Lisu population from southwestern China and other ethnic groups.Eighty VIP variants in 37 genes were selected from the pharmacogenomic knowledge base (PharmGKB), and compared with genotype data of the Lisu population then compared with other 11 populations from the HapMap dataset and previously published data including Miao, Li, Deng, Sherpa, Lhoba, Tibetan, Kirghiz, Tajik, Mongol, Shaanxi Han ethnic, and Uygur populations.VDR rs1540339, MTHFR rs1801131, P2RY1 rs701265, and PTGS2 rs689466 were significantly different between Lisu and 11 HapMap populations. ANKK1 rs1800497 was the least statistical significant locus among selected single nucleotide polymorphisms. In addition, genetic background of Lisu was strongly closest to Shaanxi Han ethnic cohort, and followed by Chinese in metropolitan Denver population based on population structure and F-statistics analyses.Our results showed significant interethnic differences between Lisu and other populations, which will give useful information for prospective studies and better individualized treatments.

Immunomodulation by vitamin D

Vitamin D exerts several immunological functions in addition to its homeostatic functions on calcium and bone metabolism. Current data show that relative vitamin D deficiency (< 75 nmol/l 25-hydroxyvitamin D) as well as acquired seasonal vitamin D deficiency (< 50 nmol/l) are frequent in Germany. As confirmed by our own data, UV exposure plays a major role for maintenance of vitamin D status, e.g., in patients with UV-triggered diseases, vitamin D deficiency is more frequent, even throughout the year. The beneficial impact of vitamin D on immune functions is highlighted by epidemiologic, genetic, and experimental evidence. In the past years, numerous publications have presented associations between vitamin D deficiency, on the one hand, and severity and prevalence of allergic asthma in children and adults, on the other hand.

Single Nucleotide Polymorphisms in the Vitamin D Receptor Gene (VDR) May Have an Impact on Acute Pancreatitis (AP) Development: A Prospective Study in Populations of AP Patients and Alcohol-Abuse Controls

Vitamin D imbalance is suggested to be associated with the development of pancreatitis. Single nucleotide polymorphisms (SNPs), Apa-1, Bsm-1, Fok-1, and Taq-1, in the vitamin D receptor gene (VDR) are known in various diseases, but not yet in pancreatitis. The aim of this study was to explore possible associations of the four SNPs in the VDR receptor gene in a population of acute pancreatitis patients and alcohol-abuse controls, and to investigate the association with acute pancreatitis (AP) susceptibility. The study population (n = 239) included acute pancreatitis patients (n = 129) and an alcohol-abuse control group (n = 110). All patients met the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) criteria for alcohol dependence. DNA was extracted from peripheral leukocytes and analyzed for VDR polymorphisms using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Odd ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression analysis. To date, we have found allele T in Taq-1 (OR = 2.61; 95% CI: 1.68⁻4.03; p < 0.0001) to be almost three times more frequent in the AP group compared to the alcohol-abuse control patients. Polymorphism Taq-1 occurring in the vitamin D receptor may have an impact on the development of acute pancreatitis due to the lack of the protective role of vitamin D.

Evaluation of 1,25-dihydroxyvitamin D3 pathway in patients with chronic urticaria

BACKGROUND

Previous studies showed the role of vitamin D (Vit D) on the progression of chronic urticaria. To the best of our knowledge, there are no other results regarding the contribution of single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP) genes in chronic urticaria (CU).

AIM

In the present study, we investigated the Vit pathway and the association between VDR and VDBP gene polymorphisms and CU risk in Iranian population.

METHODS

All participating individuals in the present study were evaluated for serum Vit D and VDBP concentration VDR rs1544410 and rs2228570 and VDBP rs7041using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The associations of studied analytes and three SNPs with clinical and laboratory outcomes were investigated in CU patients.

RESULTS

Patients with CU showed lower Vit D compared to controls (19.26 ± 1.26 vs. 31.72 ± 7.14 ng/ml, P-value = 0.006). There was a significant correlation between Vit D levels and urticaria activity score. Serum VDBP was significantly higher in CU patients than controls (1317.3 ± 183.71 vs. 395.77 ± 12.96 µg/ml, P-value <0.0001) and had a positive correlation to progression of CU. The A allele of this polymorphism might be a potential risk factor for progression of CU [odds ratio 4.3434, 95% confidence interval (1.7331-10.8852), Z-statistic = 3.133, P-value = 0.0017].

CONCLUSION

In summary, this study demonstrated that change in Vit D pathway in the level of gene or protein may be a risk factor for progression of CU.

Genetic polymorphisms of pharmacogenomic VIP variants in the Yi population from China

INTRODUCTION

Drug response and target therapeutic dosage are different among individuals. The variability is largely genetically determined. With the development of pharmacogenetics and pharmacogenomics, widespread research have provided us a wealth of information on drug-related genetic polymorphisms, and the very important pharmacogenetic (VIP) variants have been identified for the major populations around the world whereas less is known regarding minorities in China, including the Yi ethnic group. Our research aims to screen the potential genetic variants in Yi population on pharmacogenomics and provide a theoretical basis for future medication guidance.

MATERIALS AND METHODS

In the present study, 80 VIP variants (selected from the PharmGKB database) were genotyped in 100 unrelated and healthy Yi adults recruited for our research. Through statistical analysis, we made a comparison between the Yi and other 11 populations listed in the HapMap database for significant SNPs detection. Two specific SNPs were subsequently enrolled in an observation on global allele distribution with the frequencies downloaded from ALlele FREquency Database. Moreover, F-statistics (Fst), genetic structure and phylogenetic tree analyses were conducted for determination of genetic similarity between the 12 ethnic groups.

RESULTS

Using the χ2 tests, rs1128503 (ABCB1), rs7294 (VKORC1), rs9934438 (VKORC1), rs1540339 (VDR) and rs689466 (PTGS2) were identified as the significantly different loci for further analysis. The global allele distribution revealed that the allele "A" of rs1540339 and rs9934438 were more frequent in Yi people, which was consistent with the most populations in East Asia. F-statistics (Fst), genetic structure and phylogenetic tree analyses demonstrated that the Yi and CHD shared a closest relationship on their genetic backgrounds. Additionally, Yi was considered similar to the Han people from Shaanxi province among the domestic ethnic populations in China.

CONCLUSIONS

Our results demonstrated significant differences on several polymorphic SNPs and supplement the pharmacogenomic information for the Yi population, which could provide new strategies for optimizing clinical medication in accordance with the genetic determinants of drug toxicity and efficacy.

Etiologic risk factors and vitamin D receptor gene polymorphisms in under one-year-old infants with urolithiasis

The incidence of urinary tract stones in infancy has been increasing in Turkey. Risk factors and vitamin D receptor (VDR) gene polymorphisms were investigated in infants aged < 1 year who had stones. Forty infants with urinary tract stones and 80 infants without stones, aged < 1 year were enrolled in this study. Detailed surveys were taken of all infants, metabolic parameters and ApaI and FokI VDR gene polymorphisms were investigated. Infants with stones tended to be more commonly fed formula and multivitamins (vitamins A, C, D) (p < 0.05). Positive family history came into prominence in the stony group (p < 0.05). There were no significant differences in ApaI and FokI VDR gene polymorphisms between the groups with stones and the control groups. However, CA genotype of ApaI polymorphism was associated with family history and C allele of ApaI was related with family history and hypercalciuria (p < 0.05). Hypercalciuria emerged as an underlying metabolic abnormality in the etiology of stones, and was observed at a rate of 38%. Infants who are given formula and multivitamins for vitamin D supplementation are at increased risk for the formation of urinary tract stones. VDR gene polymorphisms cause the formation of urinary tract stones and affect calcium (Ca) metabolism.

Vitamin D Receptor Gene Polymorphisms Associated with Childhood Autism

Background: Autism spectrum disorder (ASD) is a group of heterogeneous, behaviorally defined disorders whereby currently no biological markers are common to all affected individuals. A deregulated immune response may be contributing to the etiology of ASD. The active metabolite of vitamin D₃ has an immunoregulatory role mediated by binding to the vitamin D receptor (VDR) in monocyte, macrophages, and lymphocytes. The effects of vitamin D and interaction with the VDR may be influenced by polymorphism in the VDR gene. Methods: Genetic association of four different VDR polymorphisms (Apa-I, Bsm-I, Taq-I, Fok-I) associated with susceptibility to the development of autism in children was investigated. Results: We uniquely found an association between the presence of the T allele at position Taq-I and presence of the a allele at position Apa-I of the VDR gene with decreased ASD incidence. There was also an association between female gender and the presence of the T allele. We found no statistical significant correlation between VDR single nucleotide polymorphisms (SNPs) and vitamin D₃ concentration in serum of ASD children. Conclusion: Genetic polymorphism in two SNP in VDR may be correlated with development of ASD symptoms by influencing functionality of vitamin D₃ metabolism, while vitamin D₃ levels were not significantly different between ASD and non-ASD children.

Vitamin D Receptor Gene Polymorphisms in Serbian Patients With Bronchial Asthma: A Case-Control Study

Vitamin D and single nucleotide polymorphisms (SNPs) in vitamin D receptor (VDR) gene are potentially involved in the pathogenesis of bronchial asthma (BA); however, precise mechanisms by which vitamin D reduces the inflammation and the role of VDR SNPs in BA are not completely understood. The aim of this study was to examine the possible associations of FokI, BsmI, ApaI, and TaqI SNPs with BA. A total of 168 subjects were screened for VDR SNPs using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. The obtained results showed statistically significant differences in the distribution of FokI genotypes (df = 2; P = 0.008) and alleles (P = 0.002; OR = 0.446; 95%CI = 0.264-0.752) between patients and controls. Distributions of BsmI, ApaI, and TaqI genotypes and alleles did not show statistical differences. BsmI, ApaI, and TaqI SNPs are in linkage disequilibrium (LD) in the whole studied group, as well as in BA patients and controls. The strongest LD was observed between BsmI and TaqI (r²  = 0.69 for all subjects in the study; r²  = 0.75 in BA; r²  = 0.64 in controls), while lower values of LD were observed for BsmI and ApaI, and ApaI and TaqI SNPs. This is the first study that examined the association of VDR SNPs (FokI, BsmI, ApaI, and TaqI) in Serbian patients with BA indicating protective effect of FF genotype and F allele of FokI SNP on BA development. J. Cell. Biochem. 118: 3986-3992, 2017. © 2017 Wiley Periodicals, Inc.

Genetic associations with viral respiratory illnesses and asthma control in children

BACKGROUND

Viral respiratory infections can cause acute wheezing illnesses in children and exacerbations of asthma.

OBJECTIVE

We sought to identify variation in genes with known antiviral and pro-inflammatory functions to identify specific associations with more severe viral respiratory illnesses and the risk of virus-induced exacerbations during the peak fall season.

METHODS

The associations between genetic variation at 326 SNPs in 63 candidate genes and 10 phenotypes related to viral respiratory infection and asthma control were examined in 226 children enrolled in the RhinoGen study. Replication of asthma control phenotypes was performed in 2128 children in the Copenhagen Prospective Study on Asthma in Childhood (COPSAC). Significant associations in RhinoGen were further validated using virus-induced wheezing illness and asthma phenotypes in an independent sample of 122 children enrolled in the Childhood Origins of Asthma (COAST) birth cohort study.

RESULTS

A significant excess of P values smaller than 0.05 was observed in the analysis of the 10 RhinoGen phenotypes. Polymorphisms in 12 genes were significantly associated with variation in the four phenotypes showing a significant enrichment of small P values. Six of those genes (STAT4, JAK2, MX1, VDR, DDX58, and EIF2AK2) also showed significant associations with asthma exacerbations in the COPSAC study or with asthma or virus-induced wheezing phenotypes in the COAST study.

CONCLUSIONS

We identified genetic factors contributing to individual differences in childhood viral respiratory illnesses and virus-induced exacerbations of asthma. Defining mechanisms of these associations may provide insight into the pathogenesis of viral respiratory infections and virus-induced exacerbations of asthma.

Sequence analysis of four vitamin D family genes (VDR, CYP24A1, CYP27B1 and CYP2R1) in Vogt-Koyanagi-Harada (VKH) patients: identification of a potentially pathogenic variant in CYP2R1

BACKGROUND

VKH is a rare autoimmune disease. Decreased level of vitamin D has recently been found to be involved in the pathogenesis of Vogt-Koyanagi-Harada (VKH) disease. This study was designed to screen the vitamin D pathway genes for pathogenic mutations, if any, in VKH patients.

METHODS

Genomic DNA was extracted from blood samples collected from patients with VKH disease and healthy controls. Entire coding region, exon-intron junctions of four genes were sequenced in DNA from 39 Saudi VKH patients and 50 ethnically matched healthy individuals. All patients and controls were unrelated.

RESULTS

Vitamin D levels in VKH patients were found either insufficient (21-29 ng/mL) or deficient (<20 ng/mL). Sequencing analysis of the VDR, CYP24A1, CYP27B1 and CYP2R1 detected twelve nucleotide changes in these genes in our cohort of 39 patients; 4 of which were non-coding, 6 were synonymous coding and 2 were non-synonymous coding sequence changes. All synonymous coding variants were benign polymorphisms with no apparent clinical significance. A non-synonymous coding sequence variant (c.2 T > C; p.1Met?) found in VDR is an initiation coding change and was detected in control individuals as well, while another variant (c.852G > A; p.284 M > I) found in CYP2R1 is predicted to be disease causing by mutationtaster software. This potentially pathogenic variant was found in 17 out of 39 VKH patients.

CONCLUSIONS

Screening of four Vitamin D pathway genes in 39 VKH patients shows that a potentially pathogenic sequence variant in CYP2R1 may cause VKH in a subset of patients. These findings support the previous observation that low vitamin D levels might play a role in VKH pathogenesis and mutations in genes involved in vitamin D anabolism and catabolism might be of importance in VKH pathobiology.

Vitamin D and the Pathogenesis of Inflammatory Bowel Disease

Vitamin D has traditionally been known for its role in bone metabolism, but emerging evidence has suggested a broader role for vitamin D in immune regulation. Vitamin D deficiency has been associated with the pathogenesis of diverse autoimmune disorders and has similarly been implicated as a contributor to inflammatory bowel disease. In this review, we discuss animal, in vitro, genetic, and epidemiologic studies that have linked vitamin D deficiency with inflammatory bowel disease pathogenesis or severity. Nonetheless, we present the caveat in interpreting these studies in the context of reverse causation: Does vitamin D deficiency lead to gastrointestinal disease, or does gastrointestinal disease (with related changes in dietary choices, intestinal absorption, nutritional status, lifestyle) lead to vitamin D deficiency?

Maternal vitamin D status and childhood asthma, wheeze, and eczema: A systematic review and meta-analysis

BACKGROUND

Maternal vitamin D status has been reported to be associated with childhood allergic diseases. However, this association remains to be fully elucidated.

METHODS

A systematic review and meta-analysis was conducted using prospective cohort studies that examined the association between maternal vitamin D status and childhood allergic diseases including wheeze, eczema and asthma. We searched electronic databases of PubMed, EMBASE, the Cochrane library, the Wanfang (Chinese) database, the VIP (Chinese) database, and Chinese National Knowledge Infrastructure (CNKI) up to August 2014. Odds ratios and 95% confidence intervals (CIs) from individual studies were synthesized using a fixed effects model.

RESULTS

Four studies on the association between maternal vitamin D status and childhood asthma (3666 mother-child pairs), four studies on the association between maternal vitamin D status and childhood wheeze (2225 mother-child pairs) and three papers on the association between maternal vitamin D status and childhood eczema (2172 mother-child pairs) met our inclusion criteria. Maternal vitamin D status during pregnancy was associated with childhood eczema (pooled OR=0.904, 95% CI=0.831-0.983). However, the meta-analysis showed no statistical association between maternal vitamin D status and childhood asthma (pooled OR=0.981, 95% CI=0.944-1.019) or childhood wheeze (pooled OR=0.995, 95% CI=0.982-1.009).

CONCLUSIONS

Our meta-analysis found that lower maternal vitamin D during pregnancy was associated with an increased risk of childhood eczema but was not associated with childhood asthma or wheeze. The role of maternal vitamin D as an important protective factor for the development of childhood eczema remains to be elucidated.

Association of T-regulatory cells and CD23/CD21 expression with vitamin D in children with asthma

BACKGROUND

Children with asthma have low vitamin D levels; however, we do not know whether low vitamin D is associated with impaired T-regulatory (Treg) cell population or high IgE receptors (CD23 and CD21) on B cells.

OBJECTIVE

To examine Treg cell function, CD23 and CD21 receptors, vitamin D, and vitamin D-regulating enzymes in children with asthma.

METHODS

Sixty children (2-6 years old) with asthma and 60 age-matched healthy children were selected as study participants. After collecting demographic and clinical data, blood samples were collected. Treg cells and CD23/CD21 expressions were evaluated by flow cytometry, 25-hydroxyvitamin D3 (25[OH]D3) was quantified by high-performance liquid chromatography, and cytokines and total IgE were estimated by enzyme-linked immunosorbent assay. Messenger RNA (mRNA) expressions of FOXP3, CD23, CD21, vitamin D receptors, and vitamin D-regulating enzymes were assessed by reverse transcription-polymerase chain reaction.

RESULTS

The 25(OH)D3 concentrations and proportion of Treg cells were lower (P < .05) among children with asthma. In contrast, the proportions of B cells with CD23 and CD21 expression were higher (P < .05) in patients with asthma compared with controls. Interleukin 10 and transforming growth factor β were also altered in asthma. The mRNA expression of CD23, CD21, and vitamin D receptors was up-regulated, whereas mRNA expression of vitamin D-regulating enzymes, CYP2R1, CYP27B1, and vitamin D binding protein (except CYP24A1) were up-regulated among children with asthma.

CONCLUSION

The current study found impaired Treg cell population and high numbers of B cells with IgE receptors (CD23 and CD21) and altered regulatory cytokines in children with asthma, suggesting impaired immune regulation.

A Hospital Based Study to Establish the Correlation between Recurrent Wheeze and Vitamin D Deficiency Among Children of Age Group Less than 3 Years in Indian Scenario

INTRODUCTION

Early childhood wheezing is a heterogeneous condition, which has several phenotypic expressions and a complex relationship with the development of asthma later in life. New studies indicate the prevalence of recurrent wheeze to be associated with Vitamin D deficiency. This has not been explored in Indian settings widely, mandating this exploration.

AIM

To determine the severity of Vitamin D deficiency and its association with recurrent wheeze in children less than 3 years of age.

MATERIALS AND METHODS

Consecutive type of non-probability sampling was followed for selection of study subjects with a total sample size to be 122 children in the Hospital setting. A pre- formed, pre- tested, structured interview schedule was used to obtain information. Estimation of 25 (OH) Vitamin D was done using ELISA method. Kit used for estimation was DLD Diagnostika GMBH 25(OH) Vitamin D ELISA from Germany. Standard statistical tools were used including Logistic regression analysis, and ROC curve, p value <0.05 was considered to be statistically significant. SPSS software version 17.0 was used.

RESULTS

Each 10ng/ml decrease in Vitamin D level is associated with 7.25% greater odds of wheezing. Our study also suggests, exclusive breast feeding and delaying of complementary feeding beyond 6 months of age are significant predictors of Vitamin D deficiency and have indirect association with increased incidence of wheezing in children.

CONCLUSION

The study concluded that Vitamin D deficiency is associated with increased risk of recurrent wheezing.

Vitamin D influences asthmatic pathology through its action on diverse immunological pathways

The prevalence of vitamin D insufficiency and deficiency has increased markedly in recent decades to current epidemic levels (Hyppönen E, et al. Am J Clin Nutr 2007;85:860-868). In parallel, there has been an increase in the incidence of a range of immune-mediated conditions ranging from cancer to autoimmune and respiratory diseases, including chronic obstructive pulmonary disease and asthma (Holick MF. N Engl J Med 2007;357:266-281; Finklea et al. Adv Nutr 2011;2:244-253). There is also an association with increased respiratory infections, which are the most common cause of asthma exacerbations (Finklea et al. Adv Nutr 2011;2:244-253). Together, this has resulted in considerable interest in the therapeutic potential of vitamin D to prevent and improve treatment of asthma and other respiratory diseases. To this end, data from clinical trials involving supplementation with active vitamin D, or more commonly a precursor, are starting to emerge. This review considers mechanisms by which vitamin D may act on the immune system to dampen inappropriate inflammatory responses in the airway while also promoting tolerance and antimicrobial defense mechanisms that collectively maintain respiratory health.

Association of vitamin D receptor gene polymorphisms and vitamin D levels with asthma and atopy in Cypriot adolescents: a case-control study

Background

Polymorphisms in the vitamin D receptor (VDR) gene have been studied in immune-related disorders either as independent contributors or in combination with vitamin D concentration. Vitamin D and VDR have been independently linked to asthma susceptibility. We investigated whether VDR variants were associated independently or in relation to vitamin D levels with asthma in Cypriot adolescents.

Methods

We studied 190 current wheezers, 69 of which were categorized as active asthmatics and 671 healthy controls. We determined three VDR genotypes (BsmI, TaqI, ApaI) and measured serum 25(OH)D levels. Logistic regression and stratified analyses by the presence of hypovitaminosis D (≤20 ng/ml) were used to evaluate the association of the VDR variants with asthma.

Results

The distribution of TaqI genotypes was significantly different between controls and current wheezers (p = 0.030) or active asthmatics (p = 0.014). The tt genotype was over-represented in wheezers (19.2 %) and asthmatics (21.3 %) compared to respective controls (12.9 %). No difference was observed between controls, current wheezers and active asthmatics in the genotypic distribution of BsmI and ApaI polymorphic sites. After stratification by the presence of hypovitaminosis D, a significant association was detected between tt genotype of TaqI polymorphism with wheezing (OR: 1.97, 95 % CI: 1.12, 3.46) and asthma (OR: 2.37, 95CI%: 1.02, 5.52) only in those with normal vitamin D levels (>20 ng/ml) but not in subjects with low vitamin D.

Conclusions

The minor TaqI genotype of VDR is associated with asthma in Cypriot adolescents. This polymorphism may contribute to asthma susceptibility primarily under conditions of normal vitamin D levels (>20 ng/ml).

Electronic supplementary material

The online version of this article (doi:10.1186/s40248-015-0025-0) contains supplementary material, which is available to authorized users.

Vitamin D levels and vitamin D receptor gene polymorphisms in asthmatic children: a case-control study

BACKGROUND

Vitamin D deficiency and single nucleotide polymorphisms (SNP) in the gene encoding vitamin D receptor (VDR) have been associated with asthma.

OBJECTIVE

To compare 25-hydroxyvitamin D (25OHD) levels and the frequency of 3 SNPs in the VDR gene between asthmatic and healthy children.

METHODS

In persistent asthmatic and healthy control children, the 25OHD levels were measured using radioimmunoassay and SNPs (FokI, ApaI, and TaqI) were analyzed by a PCR-RFLP assay. Relevant medical history was collected.

RESULTS

About 75 asthmatic (median age: 9.1 years) and 227 healthy children (10.3 years) were studied. In the whole population, the proportion of sufficient, insufficient, and deficient levels of 25OHD were 14.9%, 44%, and 41.1%, respectively. 25OHD sufficiency status was similar in asthmatic and healthy children (p = 0.57). However, the proportion of 25OHD sufficient levels among asthmatics according to the Global Initiative for Asthma treatment steps 2, 3, and 4 was significantly different (8.6%, 16.6%, and 43.7%, respectively, p = 0.046). All patients on step 4 of the treatment (16/16) were heterozygous for the C allele (FokI VDR SNP). There was a lower presence of the C allele among asthmatics in step 2 (30/33), step 3 (16/24), and controls (45/50), p = 0.007, but this significance did not persist after logistic regression. No significant differences in ApaI and TaqI were found.

CONCLUSIONS

We found a possible association of vitamin D sufficiency status and FokI C allele with higher requirement of therapy to reach asthma control, suggesting that it may be involved in treatment response. Variations in VDR might also play a role in the 25OHD levels.

Childhood asthma and spirometric indices are associated with polymorphic markers of two vitamin D 25-hydroxylase genes

BACKGROUND

Polymorphic markers of vitamin D pathway genes have been associated with asthma traits in different White populations. This study investigated the relationship between asthma phenotypes and single nucleotide polymorphisms (SNPs) of vitamin D receptor (VDR), vitamin D binding protein (GC), two 25-hydroxylases (CYP2R1 and CYP27A1), and 1α-hydroxylase (CYP27B1) in Hong Kong Chinese children.

METHODS

23 SNPs of the five vitamin D pathway genes were successfully genotyped in 914 asthmatic children and 1231 non-allergic controls. Genotypic and haplotypic associations with asthma phenotypes (diagnosis, spirometric indices, total IgE, and eosinophil percentage) were analyzed by multivariate regression. Generalized multifactor dimensionality reduction was used to detect epistatic interactions between SNPs for asthma phenotypes.

RESULTS

Several SNPs of CYP27A1, CYP27B1, GC, and CYP2R1 were associated with asthma or spirometric indices, although only the association between FEV1 and CYP2R1 rs7935792 passed Bonferroni correction (p = 2.73 × 10(-4) ). Patients with CC genotype of rs7935792 had higher FEV1 than those with the other two genotypes. Asthma was also associated with TT haplotype of CYP27A1 and AGGATA haplotype of CYP2R1 (p = 0.021 and 0.024, respectively). Besides, strong association was found between FEV1 and GATAG of CYP2R1 (β = 13.37, p = 4.83 × 10(-4) ). GMDR failed to identify any 2-locus to 4-locus interaction that modulated asthma or spirometric indices.

CONCLUSIONS

Several SNPs and haplotypes of CYP2R1 are associated with asthma diagnosis and FEV1 in children. Asthma is also modestly associated with a CYP27A1 haplotype. These two 25-hydroxylase genes may be genetic determinants for asthma phenotypes in children.

Association between vitamin D and respiratory outcomes in Canadian adolescents and adults

BACKGROUND

Asthma is one of the most prevalent chronic diseases worldwide, affecting more than 200 million people. Vitamin D deficiency has been reported among individuals with asthma and might play a role in asthma exacerbations. In this cross-sectional study, we investigated the association of serum 25-hydroxy vitamin D [25(OH)D] levels and current asthma, ever asthma, and lung function.

METHODS

Data from 3937 subjects aged 13-69 years who participated in the Canadian Health Measures Survey - Cycle 1 were considered in this study. Serum 25(OH)D levels were categorized into ≤49 nmol/L (low), 50-74 nmol/L (moderate) and ≥75 nmol/L (high).

RESULTS

The proportion of subjects with current and ever asthma was greater in the lower 25(OH)D category than in moderate and high categories. After adjusting for potential confounders, subjects in the low 25(OH)D levels were more likely to have current asthma than those in the moderate levels (OR: 1.54, 95% CI: 1.01-2.36). Low 25(OH)D levels were also associated with ever asthma (OR: 2.12, 95% CI: 1.40-3.21) among those with a family history of asthma and this association was stronger in those with asthma onset before 20 years of age. High 25(OH)D levels were associated with lower mean value of FEV1/FVC ratio. No significant association was observed between 25(OH)D levels and other lung function measurements.

CONCLUSION

In this study, 25(OH)D levels below 50 nmol/L were associated with an increased risk of current and ever asthma. Further exploration of this relationship is needed to determine the optimal level of vitamin D in the management of asthma in adolescents and adults.

Polymorphism rs2239185 in vitamin D receptor gene is associated with severe community-acquired pneumonia of children in Chinese Han population: a case-control study

Vitamin D receptor (VDR) is a potential candidate gene for community-acquired pneumonia (CAP). Examining the susceptibility VDR gene for CAP is essential for early intervention, prevention of related complications, and improvement of outcome. A case-control study was performed to examine the association between rs2239185 of VDR gene and CAP among children in Chinese Han population. Polymerase chain reaction and direct sequencing were used to genotype rs2239185 in 91 CAP children and 94 healthy children. For rs2239185, individuals with TT genotype showed a significantly higher risk of CAP than those with CC plus CT genotypes (P = 0.008). The occurrence of T allele of rs2239185 was significantly more frequent in CAP children than those in normal controls (P = 0.045).We found through stratification analysis that CAP children with systemic inflammatory response syndrome (SIRS), leukocyte count (WBC) >10 × 10(9)/L, C-reactive protein (CRP) >25 mg/L, procalcitonin (PCT) >2 ng/mL, and pediatric critical illness score <80 scores showed significantly higher frequency of TT genotype than those in normal controls (P = 0.0012, 0.0035, 0.0005, 0.0002, and 0.0021, respectively).

CONCLUSION

TT genotype of rs2239185 in VDR gene might be one of the potential genetic risk factors for CAP, and T allele of rs2239185 might be associated with the susceptibility to CAP and the severity of CAP.

Bronchial asthma and hypovitaminosis D in Saudi children

BACKGROUND

Asthma, a common lung disease in children, is caused by excessive immune responses to environmental antigens.

OBJECTIVE

Given the immuno-modulatory properties of vitamin D, the aim of the current study was to investigate the relationship between vitamin D levels and markers of asthma severity.

METHODS

This was investigated in a 70 Saudi children with and without asthma and were recruited from the King Abdul Aziz University Hospital, Jeddah, Saudi Arabia, over the period of 11 months (May 2011-April 2012). Childhood asthma control test instrument was employed to assess the level of asthma control among asthmatic patients. Anthropometric measurements were taken and interviewer-administrated questionnaire was completed for all study participants. Pulmonary function test was performed by recording changes in the peak expiratory flow. Venous blood samples were withdrawn for measurements of vitamin D, bone profile, cytokines profile (interleukin-10, tumor necrosis factor-alpha, platelets derived growth factor), and atopy markers (IgE and eosinophil count).

RESULTS

Hypovitaminosis D is highly prevalent among asthmatic children with highly significant increase in several markers of allergy and asthma severity as compared with healthy control children. Significant correlations between several inflammatory and immunological markers and vitamin D levels were also found. Finally, lower 25-hydroxyvitamin D levels were associated with a higher asthma prevalence in multivariable analysis.

CONCLUSION

Our study showed that hypovitaminosis D is highly prevalent in the whole population in addition to a highly significant increase in several markers of allergy and asthma severity among asthmatic children as compared with healthy control children.

Vitamin D and atopic dermatitis in childhood

Vitamin D features immunomodulatory effects on both the innate and adaptive immune systems, which may explain the growing evidence connecting vitamin D to allergic diseases. A wealth of studies describing a beneficial effect of vitamin D on atopic dermatitis (AD) prevalence and severity are known. However, observations linking high vitamin D levels to an increased risk of developing AD have also been published, effectively creating a controversy. In this paper, we review the existing literature on the association between AD and vitamin D levels, focusing on childhood. As of today, the role of vitamin D in AD is far from clear; additional studies are particularly needed in order to confirm the promising therapeutic role of vitamin D supplementation in childhood AD.

Vitamin D as an adjunctive therapy in asthma. Part 1: A review of potential mechanisms

Vitamin D deficiency (VDD) is highly prevalent worldwide. The classical role for vitamin D is to regulate calcium absorption form the gastrointestinal tract and influence bone health. Recently vitamin D receptors and vitamin D metabolic enzymes have been discovered in numerous sites systemically supporting diverse extra-skeletal roles of vitamin D, for example in asthmatic disease. Further, VDD and asthma share several common risk factors including high latitude, winter season, industrialization, poor diet, obesity, and dark skin pigmentation. Vitamin D has been demonstrated to possess potent immunomodulatory effects, including effects on T cells and B cells as well as increasing production of antimicrobial peptides (e.g. cathelicidin). This immunomodulation may lead to asthma specific clinical benefits in terms of decreased bacterial/viral infections, altered airway smooth muscle-remodeling and -function as well as modulation of response to standard anti-asthma therapy (e.g. glucocorticoids and immunotherapy). Thus, vitamin D and its deficiency have a number of biological effects that are potentially important in altering the course of disease pathogenesis and severity in asthma. The purpose of this first of a two-part review is to review potential mechanisms whereby altering vitamin D status may influence asthmatic disease.

Asthma: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Asthma is a common disease with enormous public health costs, and its primary prevention is an ambitious and important goal. Understanding of how host and environmental factors interact to cause asthma is incomplete, but persistent questions about mechanisms should not stop clinical research efforts aimed at reducing the prevalence of childhood asthma. Achieving the goal of primary prevention of asthma will involve integrated and parallel sets of research activities in which mechanism-oriented studies of asthma inception proceed alongside clinical intervention studies to test biologically plausible prevention ideas. For example, continued research is needed, particularly in young children, to uncover biomarkers that identify asthma risk and provide potential targets of intervention, and to improve understanding of the role of microbial factors in asthma risk and disease initiation. In terms of clinical trials that could be initiated now or in the near future, we recommend three interventions for testing: (1) preventing asthma through prophylaxis against respiratory syncytial virus and human rhinovirus infections of the airway; (2) immune modulation, using prebiotics, probiotics, and bacterial lysates; and (3) prevention of allergen sensitization and allergic inflammation, using anti-IgE. These interventions should be tested while other, more universal prevention measures that may promote lung health are also investigated. These potential universal lung health measures include prevention of preterm delivery; reduced exposure of the fetus and young infant to environmental pollutants, including tobacco smoke; prevention of maternal and child obesity; and management of psychosocial stress.

Early-life risk factors for chronic nonrespiratory diseases

We have witnessed a change in disease patterns contributing to the global burden of disease, with a shift from early childhood deaths due to the classic infectious communicable diseases to years lived with disability from chronic noncommunicable diseases. In both developing and developed countries, the years lived with disability attributable to chronic disease have increased: cardiovascular diseases by 17.7%; chronic respiratory disease by 8.5%; neurological conditions by 12.2%; diabetes by 30.0%; and mental and behavioural disorders by 5.0% over the past 20 years. Recognition of the contribution made by adverse environmental exposures in early life to noncommunicable diseases in later life is increasing. These early-life exposures appear to contribute to both chronic respiratory and chronic nonrespiratory diseases. In this State of the Art article, we aim to examine early-life environmental exposures that have an epidemiological association with chronic nonrespiratory diseases, such as obesity and type II diabetes, cardiovascular disease, and neurocognitive and behavioural problems. We will highlight the potential overlap in environmental risks with respiratory diseases, and point out knowledge gaps and research opportunities.