Effect of vitamin D3 on asthma treatment failures in adults with symptomatic asthma and lower vitamin D levels: the VIDA randomized clinical trial

Modulation of inflammatory and immune responses by vitamin D

Vitamin D (VitD) is a prohormone most noted for the regulation of calcium and phosphate levels in circulation, and thus of bone metabolism. Inflammatory and immune cells not only convert inactive VitD metabolites into calcitriol, the active form of VitD, but also express the nuclear receptor of VitD that modulates differentiation, activation and proliferation of these cells. In vitro, calcitriol upregulates different anti-inflammatory pathways and downregulates molecules that activate immune and inflammatory cells. Administration of VitD has beneficial effects in a number of experimental models of autoimmune disease. Epidemiologic studies have indicated that VitD insufficiency is frequently associated with immune disorders and infectious diseases, exacerbated by increasing evidence of suboptimal VitD status in populations worldwide. To date, however, most interventional studies in human inflammatory and immune diseases with VitD supplementation have proven to be inconclusive. One of the reasons could be that the main VitD metabolite measured in these studies was the 25-hydroxyVitD (25OHD) rather than its active form calcitriol. Although our knowledge of calcitriol as modulator of immune and inflammatory reactions has dramatically increased in the past decades, further in vivo and clinical studies are needed to confirm the potential benefits of VitD in the control of immune and inflammatory conditions.

Vitamin D and asthma in children: A systematic review and meta-analysis of observational studies

There is growing literature suggesting a link between Vitamin D deficiency and asthma in children, but systematic reviews are lacking. The aim of this study is to evaluate the prevalence of Vitamin D deficiency in asthmatic children and to assess the correlations of Vitamin D levels with asthma incidence, asthma control, and lung functions. PubMed, EMBASE, and Cochrane Library were searched for observational studies on asthma and Vitamin D. Two authors independently extracted data. Meta-analysis was performed using the Review Manager Software. A total of 23 (11 case-control, 5 cohort, and 7 cross-sectional) studies enrolling 13,160 participants were included in the review. Overall, Vitamin D deficiency and insufficiency were prevalent in 28.5% and 26.7% children with asthma, respectively. The mean 25-hydroxyvitamin D (25(OH)D) levels (10 studies) were significantly lower in asthmatic children as compared to nonasthmatic children with a mean difference of -9.41 (95% confidence interval [CI] -16.57, -2.25). The odds ratio of Vitamin D deficiency (eight case-control studies) was significantly higher among asthmatic children as compared to nonasthmatic children (odds ratio 3.41; 95% CI 2.04, 5.69). Correlations between Vitamin D levels and incidence of asthma, lung functions, and control of asthma had mixed results. To conclude, asthmatic children had lower 25(OH)D levels as compared to nonasthmatic children, but the correlations between 25(OH)D and asthma incidence, asthma control, and lung functions were varied. Well-designed randomized controlled trials are required to determine if children with asthma can benefit from Vitamin D supplementation.

Race is associated with differences in airway inflammation in patients with asthma

BACKGROUND

African American subjects have a greater burden from asthma compared with white subjects. Whether the pattern of airway inflammation differs between African American and white subjects is unclear.

OBJECTIVE

We sought to compare sputum airway inflammatory phenotypes of African American and white subjects treated or not with inhaled corticosteroids (ICSs; ICS+ and ICS-, respectively).

METHODS

We performed a secondary analysis of self-identified African American and white subjects with asthma enrolled in clinical trials conducted by the National Heart, Lung, and Blood Institute-sponsored Asthma Clinical Research Network and AsthmaNet. Demographics, clinical characteristics, and sputum cytology after sputum induction were examined. We used a sputum eosinophil 2% cut point to define subjects with either an eosinophilic (≥2%) or noneosinophilic (<2%) inflammatory phenotype.

RESULTS

Among 1018 participants, African American subjects (n = 264) had a lower FEV1 percent predicted (80% vs 85%, P < .01), greater total IgE levels (197 vs 120 IU/mL, P < .01), and a greater proportion with uncontrolled asthma (43% vs 28%, P < .01) compared with white subjects (n = 754). There were 922 subjects in the ICS+ group (248 African American and 674 white subjects) and 298 subjects in the ICS- group (49 African American and 249 white subjects). Eosinophilic airway inflammation was not significantly different between African American and white subjects in either group (percentage with eosinophilic phenotype: ICS+ group: 19% vs 16%, P = .28; ICS- group: 39% vs 35%, P = .65; respectively). However, when adjusted for confounding factors, African American subjects were more likely to exhibit eosinophilic airway inflammation than white subjects in the ICS+ group (odds ratio, 1.58; 95% CI, 1.01-2.48; P = .046) but not in the ICS- group (P = .984).

CONCLUSION

African American subjects exhibit greater eosinophilic airway inflammation, which might explain the greater asthma burden in this population.

Rapid vs Maintenance Vitamin D Supplementation in Deficient Children With Asthma to Prevent Exacerbations

BACKGROUND

Whether vitamin D reduces clinically important exacerbations of childhood asthma remains uncertain. We compared rapid to maintenance vitamin D repletion analyzed by baseline vitamin D level.

METHODS

Children presenting to the ED with moderate-to-severe asthma exacerbations and vitamin D levels ≤ 25 ng/mL underwent masked randomization, and then open dosing to either IM+oral (the latter daily) therapy or daily oral-only therapy, and were followed for 12 months. The primary outcome was patient-initiated unplanned visits for asthma exacerbations, examined two ways: cumulative proportions with an exacerbation, and average exacerbation frequency. As this was a nutrient study, we analyzed treatment groups by quartile of baseline vitamin D level, collecting repeat levels and clinical observations at 3, 6, 9, and 12 months after enrollment.

RESULTS

One hundred and sixteen patients in the IM+oral cohort vs 115 in the oral-only cohort had similar mean (SD) baseline levels: 15.1 (5.4) vs 15.8 (5.2) ng/mL (range, 3-25 ng/mL). There was no difference in the primary outcome over the entire 12-month observation period. However, rapid IM+oral supplementation significantly reduced unplanned visits for asthma exacerbations for children with baseline levels of 3 to 11 ng/mL during the initial 3 months: the relative exacerbation rate for the IM+oral cohort compared with the oral-only cohort at 3 months was 0.48 (95% CI, 0.28-0.89; P = .008); average exacerbation frequency per child analysis, relative rate 0.36 (95% CI, 0.13-0.87; P = .017). Otherwise, there were no significant differences between groups.

CONCLUSIONS

Rapid compared to maintenance vitamin D supplementation for children with the lowest levels resulted in short- but not long-term reduction in asthma exacerbations.

Income is an independent risk factor for worse asthma outcomes

BACKGROUND

Socioeconomic status (SES) is associated with asthma morbidity in observational studies, but the factors underlying this association are uncertain.

OBJECTIVE

We investigated whether 3 SES correlates-low income, low education, and high perceived stress-were independent risk factors for treatment failure and asthma exacerbations in the context of a randomized controlled trial.

METHODS

The effect of low SES (household income of <$50,000/y and household educational level of less than a Bachelor's degree) and high perceived stress (defined as a score of >20 on a perceived stress scale) on asthma morbidity was analyzed in 381 participants by using Poisson regression models. The primary outcome was treatment failure (defined in the trial protocol as a significant clinical or airflow deterioration), and the secondary outcome was asthma exacerbations requiring systemic corticosteroids.

RESULTS

Fifty-four percent of participants had a low income, 40% had a low educational level, and 17% had high perceived stress levels. Even after adjusting for race and other important confounders, participants with lower income had higher rates of both treatment failures (rate ratio, 1.6; 95% CI, 1.1-2.3; P = .03) and exacerbations (rate ratio, 1.9; 95% CI, 1.1-3.3; P = .02). Adherence with inhaled corticosteroids was similarly high for both income categories. Education and perceived stress were not significantly associated with either outcome.

CONCLUSIONS

In the context of a randomized controlled trial, participants with lower income were more likely to experience adverse asthma outcomes independent of education, perceived stress, race, and medication adherence.

Evaluation of selected immunological parameters and the concentration of vitamin D in children with asthma. Case-control study

Due to the increased incidence of allergic diseases and emerging effects of unsatisfactory control of asthma, new mechanisms for supervising the immune system should be searched. The aim of the study was to analyze the percentage of CD3, CD4, CD8, CD19, CD16/56, NKT, CD3 anti-HLADR3 and Foxp3 regulatory lymphocytes in patients with asthma. Additionally the correlation between immune parameters, severity of asthma and serum concentration of vitamin D was performed. 25 children diagnosed with asthma were enrolled. Disease severity was assessed with the Asthma Control Test (ACT) and spirometry. The control group consisted of 15 healthy children. Venous blood from each patient was collected on EDTA or on "clott". Phenotypes of lymphocytes were evaluated by flow cytometry. Vitamin D concentration was assessed by chemiluminescent immunoassay (CLIA) technology. There was a significant decrease in the percentage of T regulatory cells (p < 0.006) in children with asthma compared to the control group. There were no significant differences in the other investigated immunological parameters. In addition, in asthma group statistically significant decreased of vitamin D concentration (p < 0.04) was observed. There were also no significant correlations between vitamin D3 concentration and the course of asthma or percentage of regulatory cells. The results confirmed the role of regulatory T cells in the pathogenesis of asthma. Effects of vitamin D on the severity of the disease has not been proven.

Vitamin D levels and susceptibility to asthma, elevated immunoglobulin E levels, and atopic dermatitis: A Mendelian randomization study

BACKGROUND

Low circulating vitamin D levels have been associated with risk of asthma, atopic dermatitis, and elevated total immunoglobulin E (IgE). These epidemiological associations, if true, would have public health importance, since vitamin D insufficiency is common and correctable.

METHODS AND FINDINGS

We aimed to test whether genetically lowered vitamin D levels were associated with risk of asthma, atopic dermatitis, or elevated serum IgE levels, using Mendelian randomization (MR) methodology to control bias owing to confounding and reverse causation. The study employed data from the UK Biobank resource and from the SUNLIGHT, GABRIEL and EAGLE eczema consortia. Using four single-nucleotide polymorphisms (SNPs) strongly associated with 25-hydroxyvitamin D (25OHD) levels in 33,996 individuals, we conducted MR studies to estimate the effect of lowered 25OHD on the risk of asthma (n = 146,761), childhood onset asthma (n = 15,008), atopic dermatitis (n = 40,835), and elevated IgE level (n = 12,853) and tested MR assumptions in sensitivity analyses. None of the four 25OHD-lowering alleles were associated with asthma, atopic dermatitis, or elevated IgE levels (p ≥ 0.2). The MR odds ratio per standard deviation decrease in log-transformed 25OHD was 1.03 (95% confidence interval [CI] 0.90-1.19, p = 0.63) for asthma, 0.95 (95% CI 0.69-1.31, p = 0.76) for childhood-onset asthma, and 1.12 (95% CI 0.92-1.37, p = 0.27) for atopic dermatitis, and the effect size on log-transformed IgE levels was -0.40 (95% CI -1.65 to 0.85, p = 0.54). These results persisted in sensitivity analyses assessing population stratification and pleiotropy and vitamin D synthesis and metabolism pathways. The main limitations of this study are that the findings do not exclude an association between the studied outcomes and 1,25-dihydoxyvitamin D, the active form of vitamin D, the study was underpowered to detect effects smaller than an OR of 1.33 for childhood asthma, and the analyses were restricted to white populations of European ancestry. This research has been conducted using the UK Biobank Resource and data from the SUNLIGHT, GABRIEL and EAGLE Eczema consortia.

CONCLUSIONS

In this study, we found no evidence that genetically determined reduction in 25OHD levels conferred an increased risk of asthma, atopic dermatitis, or elevated total serum IgE, suggesting that efforts to increase vitamin D are unlikely to reduce risks of atopic disease.

Vitamin D Insufficiency and Asthma in a US Nationwide Study

BACKGROUND

Vitamin D insufficiency (a serum 25-hydroxy vitamin D level of <30 ng/mL) has been associated with asthma morbidity.

OBJECTIVE

To examine vitamin D insufficiency, asthma, and lung function among US children and adults.

METHODS

Using data from the National Health and Nutrition Examination Survey from 2001 to 2010, we examined vitamin D insufficiency and (1) current asthma or wheeze in 10,860 children (6-17 years) and 24,115 adults (18-79 years) and (2) lung function in a subset of participants. Logistic or linear regression was used for the multivariable analysis, adjusting for age, sex, race/ethnicity, income, body mass index, smoking, and C-reactive protein level.

RESULTS

Vitamin D insufficiency was associated with current asthma (odds ratio, 1.35; 95% CI, 1.11-1.64) and current wheeze in children, as well as with current wheeze in adults (odds ratio, 1.17; 95% CI, 1.04-1.31). After stratifying the analysis by race/ethnicity and (in adults) current smoking, vitamin D insufficiency was associated with current asthma and wheeze in non-Hispanic white children only; in adults, vitamin D insufficiency was associated with current wheeze in non-Hispanic whites and blacks. Vitamin D insufficiency was also associated with lower FEV1 and forced vital capacity in children and adults. When analyzing each National Health and Nutrition Examination Survey wave separately, vitamin D insufficiency prevalence was 72% to 76% from 2001 to 2006, and then decreased from 2007 to 2010 (64%-65%); interestingly, asthma prevalence decreased for the first time from the period 2007 to 2008 (8.2%) to the period 2009 to 2010 (7.4%).

CONCLUSIONS

We show racial/ethnic-specific associations between vitamin D insufficiency and current asthma or wheeze in children and adults. Moreover, we report parallel recent decrements in the prevalence of vitamin D insufficiency and asthma.

Vitamin D and Bronchial Asthma: An Overview of Data From the Past 5 Years

PURPOSE

Vitamin D is a potent immunomodulator capable of dampening inflammatory signals in several cell types involved in the asthmatic response. Its deficiency has been associated with increased inflammation, exacerbations, and overall poor outcomes in patients with asthma. Given the increase in the prevalence of asthma over the past few decades, there has been enormous interest in the use of vitamin D supplementation as a potential therapeutic option. Here, we critically reviewed the most recent findings from in vitro studies, animal models, and clinical trials regarding the role of vitamin D in treating bronchial asthma.

METHODS

Using the key terms [Vitamin D, asthma, clinical trials, in vivo and in vitro studies], the [PubMed, Google Scholar] databases were searched for [clinical trials, original research articles, meta-analyses, and reviews], English-language articles published from [2012] to the present. Articles that were [Articles that did not meet these criteria were excluded] excluded from the analysis.

FINDINGS

Several studies have found that low serum levels of vitamin D (< 20 ng/mL) are associated with increased exacerbations, increased airway inflammation, decreased lung function, and poor prognosis in asthmatic patients. Results from in vitro and in vivo studies in animals and humans have suggested that supplementation with vitamin D may ameliorate several hallmark features of asthma. However, the findings obtained from clinical trials are controversial and do not unequivocally support a beneficial role of vitamin D in asthma. Largely, interventional studies in children, pregnant women, and adults have primarily found little to no effect of vitamin D supplementation on improved asthma symptoms, onset, or progression of the disease. This could be related to the severity of the disease process and other confounding factors.

IMPLICATIONS

Despite the conflicting data obtained from clinical trials, vitamin D deficiency may influence the inflammatory response in the airways. Further studies are needed to determine the exact mechanisms by which vitamin D supplementation may induce antiinflammatory effects.

Association Between Severe Vitamin D Deficiency, Lung Function and Asthma Control

INTRODUCTION

To examine the relationship between severe vitamin D deficiency, asthma control, and pulmonary function in Turkish adults with asthma.

METHODS

One hundred six asthmatic patients underwent pulmonary function tests skin prick test, peripheral blood eosinophil counts, IgE, body mass index and vitamin D levels were determined. Patients were divided into 2 subgroups according to vitamin D levels (vitamin D level<10ng/ml and vitamin D level≥10 ng/ml). Asthma control tests were performed.

RESULTS

The mean age of subgroup i (vitamin D level<10) was 37±10 and the mean age of subgroup ii (vitamin D level≥10ng/ml) was 34±8. Sixty-six percent of patients had severe vitamin D deficiency (vitamin D level<10 ng/ml). There was a significant trend towards lower absolute FEV₁ (L) values in patients with lower vitamin D levels (P=.001). Asthma control test scores were significantly low in the severe deficiency group than the other group (P=.02). There were a greater number of patients with uncontrolled asthma (asthma control test scores<20) in the severe vitamin D deficiency group (P=.040). Patients with severe vitamin D deficiency had a higher usage of inhaled corticosteroids than the group without severe vitamin D deficiency (P=.015). There was a significant trend towards lower absolute FEV₁ (L) (P=.005, r=.272) values in patients with lower vitamin D levels. Vitamin D levels were inversely related with body mass index (P=.046).

CONCLUSION

The incidence of severe vitamin D deficiency was high in adult Turkish asthmatics. In addition, lower vitamin D levels were associated with poor asthma control and decreased pulmonary function.

Pharmacological targeting of allergen-specific T lymphocytes

Allergic disorders are the result of a complex pathophysiology, involving major cellular lineages and a multitude of humoral factors of the innate and adaptive immune system, and have the tendency to involve multiple organs. Consequently, even standard pharmacological treatment of allergies is rarely specific but usually targets more than one pathway/cellular system at a time. Accordingly, many of the classic anti-allergic drugs have a critical impact also on T helper cells, which are pivotal not only during the sensitization but also the maintenance phase of allergic diseases. Recent years have seen a dramatic increase of novel drugs with the potency to interfere, more or less specifically, with T lymphocyte function, which might, possibly together with classic anti-allergic drugs, help harnessing one of the central cellular players in allergic responses. A major theme in the years to come will be a thoughtful combination of previously established with recently developed treatment modalities.

Vitamin D supplementation in pregnancy, prenatal 25(OH)D levels, race, and subsequent asthma or recurrent wheeze in offspring: Secondary analyses from the Vitamin D Antenatal Asthma Reduction Trial

BACKGROUND

Nutrient trials differ from drug trials because participants have varying circulating levels at entry into the trial.

OBJECTIVE

We sought to study the effect of a vitamin D intervention in pregnancy between subjects of different races and the association between 25-hydroxyvitamin D₃ (25[OH]D) levels in pregnancy and the risk of asthma/recurrent wheeze in offspring.

METHODS

The Vitamin D Antenatal Asthma Reduction Trial is a randomized trial of pregnant women at risk of having children with asthma randomized to 4400 international units/d vitamin D or placebo plus 400 international units/d vitamin D. Asthma and recurrent wheezing until age 3 years were recorded.

RESULTS

African American (AA) women (n = 312) had lower initial levels of 25(OH)D (mean [SD], 17.6 ng/mL [8.3 ng/mL]) compared with non-AA women (n = 400; 27.1 ng/mL [9.7 ng/mL], P < .001). No racial difference was found from vitamin D supplementation in pregnancy on asthma/recurrent wheezing in offspring (P for interaction = .77). Having an initial level of greater than 30 ng/mL and being randomized to the intervention group was associated with the lowest risk for asthma/recurrent wheeze by age 3 years compared with having an initial level of less than 20 ng/mL and receiving placebo (adjusted odds ratio, 0.42; 95% CI, 0.19-0.91).

CONCLUSIONS

We did not find differences between AA and non-AA mothers in the effect of maternal vitamin D supplementation and asthma/recurrent wheeze in offspring at 3 years. Maternal supplementation of vitamin D, particularly in mothers with initial 25(OH)D levels of greater than 30 ng/mL, reduced asthma/recurrent wheeze in the offspring through age 3 years, suggesting that higher vitamin D status beginning in early pregnancy is necessary for asthma/recurrent wheeze prevention in early life.

A systematic review and meta-analysis of complementary and alternative medicine in asthma

Asthma is a chronic, inflammatory lung disease affecting around 235 million people worldwide. Conventional medications in asthma are not curative and patients have significant concerns regarding their side-effects. Consequently, many asthma patients turn to complementary and alternative medicine (CAM) for a more holistic approach to care. We systematically reviewed the available evidence on the effectiveness of CAM in the management of asthma in adults.We searched the MEDLINE, EMBASE, CINAHL, AMED and Cochrane databases for randomised controlled trials published in English between 1990 and 2016 investigating the effectiveness of oral or topical CAM in asthmatic adults. The quality of the studies was assessed using the Cochrane Risk of Bias Assessment Tool.In all, 23 eligible trials were identified covering 19 different CAMs. Overall, there was limited evidence on the effectiveness of CAM in adult asthma as most CAMs were only assessed in a single trial. CAMs with multiple trials provided null or inconsistent results. Many of the trials were rated as having high risk of bias.The existing evidence is insufficient to recommend any of the oral and topical CAMs in the management of asthma in adults.

Asthma in adolescence: Is there any news?

Asthma is a chronic disease that has a significant impact quality of life, which is particularly important in adolescence. We will discuss aspects of epidemiology, the clinical spectrum, diagnostics, and management of asthma in adolescence. In particular, we will highlight the psychological implications of having asthma during this developmental period. Data published in the past 10 years, since we last reviewed the subject, will be the main focus of this paper. The care of the teenager with asthma should take into account the rapid physical, emotional, cognitive, and social changes that occur during normal adolescence. The diagnostic process may be more difficult since teenagers tend to deny their illness. Thus, both under-diagnosis and under-assessment of asthma severity may lead to under-treatment and potentially avoidable morbidity and even mortality. Conversely, teenagers may be often misdiagnosed as having asthma or their asthma severity may be overestimated leading to inappropriate and sometimes excessive treatment. Educational programs, environmental avoidance measures, proper use of medications along with a skilled approach, and a caring attitude of health providers are all very important for successful management. Pediatr Pulmonol. 2017;52:129-138. © 2016 Wiley Periodicals, Inc.

Vitamin D and pulmonary function in obese asthmatic children

OBJECTIVE

Asthma-related morbidity is higher among children with vitamin D deficiency and obesity, morbidities that frequently co-exist among minority children. However, the effect of co-existent obesity and vitamin D deficiency on pulmonary function is poorly understood.

METHODS

We compared percent-predicted values of pulmonary function across vitamin D categories among 72 obese and 71 normal-weight Hispanic and African-American children with asthma recruited at an urban children's hospital. Serum cytokines associated with Th1 and Th2 inflammation and 25-hydroxyvitamin D (25-OHD) were quantified in fasting serum. 25-OHD levels ≥30 ng/ml were categorized as sufficient, <30 and ≥20 ng/ml as insufficient, and <20 ng/ml as deficient. The role of inflammation was investigated by regression analysis.

RESULTS

Vitamin D deficiency was present in 50% of children and did not differ by obese status. Forced Expiratory Volume in the first second (84.5 ± 9.4 vs. 94.8 ± 8.4, P < 0.001), and Functional Residual Capacity (67.5 ± 20.1 vs. 79.3 ± 19, P = 0.01) were lower among vitamin D deficient obese asthmatics than their sufficient counterparts, and Total Lung Capacity was lower than their insufficient counterparts (86.9 ± 14.3 vs. 96.6 ± 10, P = 0.01); similar associations were not observed in normal-weight asthmatics and were not influenced by systemic inflammation. No association between Th1 and Th2 inflammatory measures, vitamin D deficiency, and pulmonary function tests was found.

CONCLUSIONS

Vitamin D deficiency was associated with pulmonary function deficits among obese children, but not among normal-weight children with asthma, an association that was independent of Th1 and Th2 serum inflammatory measures. Vitamin D deficiency may be one potential mechanism underlying the obese-asthma phenotype. Pediatr Pulmonol. 2016;51:1276-1283. © 2016 Wiley Periodicals, Inc.

Serum Vitamin D Levels and Vitamin D Supplement in Adult Patients with Asthma Exacerbation

Introduction. Vitamin D deficiency has been linked to an increased risk of asthma exacerbations. Objective. This study aimed to compare vitamin D status during the period of severe asthma exacerbations and investigate if vitamin D supplementation improves asthma control. Methods. A total of 47 asthmatic patients and 40 healthy subjects participated in this study. Serum 25-hydroxyvitamin D (25(OH)D), asthma control test (ACT) score, and % predicted peak expiratory flow rate were evaluated in the period with and without severe asthma exacerbations. After that, we provided vitamin D2 supplements to the patients with low vitamin D levels for 3 months. Results. At the period of asthma exacerbation, the prevalence of vitamin D deficiency and insufficiency was 38.29% and 34.04%. There was no significant difference in the levels of serum 25(OH)D with and without asthma exacerbations but the levels were significantly higher in the healthy group. Serum 25(OH)D levels significantly correlated with ACT score. Moreover, vitamin D2 supplementation improved asthma control in uncontrolled asthma group. Conclusions. Hypovitaminosis D was common in asthmatic patients but was not the leading cause of asthma exacerbations. Serum 25(OH)D levels correlated with the ability to control asthma. Improving vitamin D status might be a benefit in uncontrolled asthmatic patients.

Folate Deficiency, Atopy, and Severe Asthma Exacerbations in Puerto Rican Children

BACKGROUND

Little is known about folate and atopy or severe asthma exacerbations. We examined whether folate deficiency is associated with number of positive skin tests to allergens or severe asthma exacerbations in a high-risk population and further assessed whether such association is explained or modified by vitamin D status.

METHODS

Cross-sectional study of 582 children aged 6 to 14 years with (n = 304) and without (n = 278) asthma in San Juan, Puerto Rico. Folate deficiency was defined as plasma folate less than or equal to 20 ng/ml. Our outcomes were the number of positive skin tests to allergens (range, 0-15) in all children and (in children with asthma) one or more severe exacerbations in the previous year. Logistic and negative binomial regression models were used for the multivariate analysis. All multivariate models were adjusted for age, sex, household income, residential proximity to a major road, and (for atopy) case/control status; those for severe exacerbations were also adjusted for use of inhaled corticosteroids and vitamin D insufficiency (a plasma 25[OH]D < 30 ng/ml).

MEASUREMENTS AND MAIN RESULTS

In a multivariate analysis, folate deficiency was significantly associated with an increased degree of atopy and 2.2 times increased odds of at least one severe asthma exacerbation (95% confidence interval for odds ratio, 1.1-4.6). Compared with children who had normal levels of both folate and vitamin D, those with both folate deficiency and vitamin D insufficiency had nearly eightfold increased odds of one or more severe asthma exacerbation (95% confidence interval for adjusted odds ratio, 2.7-21.6).

CONCLUSIONS

Folate deficiency is associated with increased degree of atopy and severe asthma exacerbations in school-aged Puerto Ricans. Vitamin D insufficiency may further increase detrimental effects of folate deficiency on severe asthma exacerbations.

Emerging concepts in smooth muscle contributions to airway structure and function: implications for health and disease

Airway structure and function are key aspects of normal lung development, growth, and aging, as well as of lung responses to the environment and the pathophysiology of important diseases such as asthma, chronic obstructive pulmonary disease, and fibrosis. In this regard, the contributions of airway smooth muscle (ASM) are both functional, in the context of airway contractility and relaxation, as well as synthetic, involving production and modulation of extracellular components, modulation of the local immune environment, cellular contribution to airway structure, and, finally, interactions with other airway cell types such as epithelium, fibroblasts, and nerves. These ASM contributions are now found to be critical in airway hyperresponsiveness and remodeling that occur in lung diseases. This review emphasizes established and recent discoveries that underline the central role of ASM and sets the stage for future research toward understanding how ASM plays a central role by being both upstream and downstream in the many interactive processes that determine airway structure and function in health and disease.

Ergocalciferol treatment does Not improve erythropoietin utilization and hospitalization rate in hemodialysis patients

BACKGROUND

Vitamin D (25-hydroxyvitamin D; 25[OH]D) deficiency (VDD) is highly prevalent in chronic kidney disease. The aim of this study was to evaluate the effect of oral ergocalciferol supplementation on requirement of erythropoietin (EPO) and active vitamin D analogues, and hospitalization rate in maintenance hemodialysis (HD) patients.

METHODS

This retrospective cohort study included 186 patients who were on HD for 3 months and had 25(OH)D levels < 30 ng/ml. Over 1-year period, 107 patients were supplemented with protocol-based ergocalciferol (D2 group) and 79 were not (control). Parameters of erythropoiesis and bone-mineral metabolism, and monthly doses of EPO and paricalcitol were assessed at 6- and 12- months of ergocalciferol supplementation. Total hospitalizations were recorded for the same year.

RESULTS

Baseline characteristics were similar across two arms except higher serum ferritin, transferrin saturation and prevalence of stroke in D2 and higher coronary artery disease in control group with overall mean ± SD 25(OH)D level of 16.8 ± 7 ng/ml. At 12 months, 25(OH)D levels increased significantly in D2 group compared to control (30.5 ± 11.7 vs. 14.2 ± 9.3 ng/ml; p < 0.001). The EPO dose remained same with no difference in hemoglobin values between the two groups during the intervention period. On multivariate regression which included above variables there was no effect of ergocalciferol treatment on EPO dose (p = ns). Hospitalization rate was similar in two arms; however, ergocalciferol treatment inversely associated with paricalcitol dose (β ± SE = -10.4 ± 2.8; p < 0.001).

CONCLUSIONS

One-year of ergocalciferol supplementation was not associated with reduction in EPO requirement or hospitalization rate in HD patients with VDD. Further studies are warranted to determine definitive role of nutritional vitamin D in these patients.

Vitamin D modulation of innate immune responses to respiratory viral infections

Vitamin D, in addition to its classical functions in bone homeostasis, has a modulatory and regulatory role in multiple processes, including host defense, inflammation, immunity, and epithelial repair. Patients with respiratory disease are frequently deficient in vitamin D, implying that supplementation might provide significant benefit to these patients. Respiratory viral infections are common and are the main trigger of acute exacerbations and hospitalization in children and adults with asthma and other airways diseases. Respiratory monocytes/macrophages and epithelial cells constitutively express the vitamin D receptor. Vitamin D, acting through this receptor, may be important in protection against respiratory infections. Whether the in vitro findings can be translated into a substantial in vivo benefit still remains uncertain. Here we review the in vitro data on the role of vitamin D in antiviral innate immunity, the data concerning the deficient levels of vitamin D in lung diseases, and the in vivo role of supplementation as protection against respiratory viral infections in healthy individuals and in patients with chronic respiratory diseases. Finally, we suggest ways of improving the effectiveness of vitamin D as an adjuvant in the prevention and treatment of acute respiratory infections.

Vitamin D for the management of asthma

BACKGROUND

Several clinical trials of vitamin D to prevent asthma exacerbation and improve asthma control have been conducted in children and adults, but a meta-analysis restricted to double-blind, randomised, placebo-controlled trials of this intervention is lacking.

OBJECTIVES

To evaluate the efficacy of administration of vitamin D and its hydroxylated metabolites in reducing the risk of severe asthma exacerbations (defined as those requiring treatment with systemic corticosteroids) and improving asthma symptom control.

SEARCH METHODS

We searched the Cochrane Airways Group Trial Register and reference lists of articles. We contacted the authors of studies in order to identify additional trials. Date of last search: January 2016.

SELECTION CRITERIA

Double-blind, randomised, placebo-controlled trials of vitamin D in children and adults with asthma evaluating exacerbation risk or asthma symptom control or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied study inclusion criteria, extracted the data, and assessed risk of bias. We obtained missing data from the authors where possible. We reported results with 95% confidence intervals (CIs).

MAIN RESULTS

We included seven trials involving a total of 435 children and two trials involving a total of 658 adults in the primary analysis. Of these, one trial involving 22 children and two trials involving 658 adults contributed to the analysis of the rate of exacerbations requiring systemic corticosteroids. Duration of trials ranged from four to 12 months, and the majority of participants had mild to moderate asthma. Administration of vitamin D reduced the rate of exacerbations requiring systemic corticosteroids (rate ratio 0.63, 95% CI 0.45 to 0.88; 680 participants; 3 studies; high-quality evidence), and decreased the risk of having at least one exacerbation requiring an emergency department visit or hospitalisation or both (odds ratio (OR) 0.39, 95% CI 0.19 to 0.78; number needed to treat for an additional beneficial outcome, 27; 963 participants; 7 studies; high-quality evidence). There was no effect of vitamin D on % predicted forced expiratory volume in one second (mean difference (MD) 0.48, 95% CI -0.93 to 1.89; 387 participants; 4 studies; high-quality evidence) or Asthma Control Test scores (MD -0.08, 95% CI -0.70 to 0.54; 713 participants; 3 studies; high-quality evidence). Administration of vitamin D did not influence the risk of serious adverse events (OR 1.01, 95% CI 0.54 to 1.89; 879 participants; 5 studies; moderate-quality evidence). One trial comparing low-dose versus high-dose vitamin D reported two episodes of hypercalciuria, one in each study arm. No other study reported any adverse event potentially attributable to administration of vitamin D. No participant in any included trial suffered a fatal asthma exacerbation. We did not perform a subgroup analysis to determine whether the effect of vitamin D on risk of severe exacerbation was modified by baseline vitamin D status, due to unavailability of suitably disaggregated data. We assessed two trials as being at high risk of bias in at least one domain; neither trial contributed data to the analysis of the outcomes reported above.

AUTHORS' CONCLUSIONS

Meta-analysis of a modest number of trials in people with predominantly mild to moderate asthma suggests that vitamin D is likely to reduce both the risk of severe asthma exacerbation and healthcare use. It is as yet unclear whether these effects are confined to people with lower baseline vitamin D status; further research, including individual patient data meta-analysis of existing datasets, is needed to clarify this issue. Children and people with frequent severe asthma exacerbations were under-represented; additional primary trials are needed to establish whether vitamin D can reduce the risk of severe asthma exacerbation in these groups.

Improved control of childhood asthma with low-dose, short-term vitamin D supplementation: a randomized, double-blind, placebo-controlled trial

BACKGROUND

In our prior randomized trial on preventing influenza, asthma attacks as a secondary outcome occurred less often in the vitamin D group than in the placebo group. We aimed to clarify whether low-dose, short-term vitamin D supplementation, in addition to standard treatments, improves control of childhood asthma.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial comparing vitamin D3 supplements (800 IU/day) with placebo for 2 months in schoolchildren with asthma. The primary outcomes were frequency and severity of asthma judging from changes in asthma control levels defined by the Global Initiative for Asthma (GINA) by collaborating doctors at 2 and 6 months.

RESULTS

Japanese schoolchildren with asthma (n = 89) were randomly assigned to receive vitamin D (n = 54) or placebo (n = 35). At 2 months, GINA asthma control was significantly more improved in the vitamin D group compared with the placebo group (P = 0.015). Childhood asthma control test (CACT) scores, a secondary outcome, were also significantly (P = 0.004) improved in the vitamin D group compared with the placebo group at 2 months, and differences remained significant (P = 0.012) at 6 months. The proportion of patients with a peak expiratory flow rate <80% predicted was significantly less in the vitamin D group (8/54: 15%) than in the placebo group (12/35: 34%) at 6 months (P = 0.032).

CONCLUSIONS

Low-dose, short-term vitamin D supplementation in addition to standard treatment may improve levels of asthma control in schoolchildren.

Asthma treatments: new and emerging therapies

BACKGROUND

As part of this primer, this article is intended to introduce new and emerging therapies for treating asthma.

METHODS

A PubMed search was performed for the years 2013 through 2015 for asthma review, asthma treatment, asthma therapy, and asthma new. Subset searches were additionally performed as suggested by information contained in the first round of searches.

RESULTS

There is continuing work toward the identification of additional cellular and molecular mechanisms of asthma. Many of these suggest additional targets for therapy. New pharmaceuticals, biologics, and procedures are reviewed in greater depth.

CONCLUSION

This is a summary of new and emerging asthma therapies.

Novel approaches to the management of noneosinophilic asthma

Noneosinophilic airway inflammation occurs in approximately 50% of patients with asthma. It is subdivided into neutrophilic or paucigranulocytic inflammation, although the proportion of each subtype is uncertain because of variable cut-off points used to define neutrophilia. This article reviews the evidence for noneosinophilic inflammation being a target for therapy in asthma and assesses clinical trials of licensed drugs, novel small molecules and biologics agents in noneosinophilic inflammation. Current symptoms, rate of exacerbations and decline in lung function are generally less in noneosinophilic asthma than eosinophilic asthma. Noneosinophilic inflammation is associated with corticosteroid insensitivity. Neutrophil activation in the airways and systemic inflammation is reported in neutrophilic asthma. Neutrophilia in asthma may be due to corticosteroids, associated chronic pulmonary infection, altered airway microbiome or delayed neutrophil apoptosis. The cause of poorly controlled noneosinophilic asthma may differ between patients and involve several mechanism including neutrophilic inflammation, T helper 2 (Th2)-low or other subtypes of airway inflammation or corticosteroid insensitivity as well as noninflammatory pathways such as airway hyperreactivity and remodelling. Smoking cessation in asthmatic smokers and removal from exposure to some occupational agents reduces neutrophilic inflammation. Preliminary studies of 'off-label' use of licensed drugs suggest that macrolides show efficacy in nonsmokers with noneosinophilic severe asthma and statins, low-dose theophylline and peroxisome proliferator-activated receptor gamma (PPARγ) agonists may benefit asthmatic smokers with noneosinophilic inflammation. Novel small molecules targeting neutrophilic inflammation, such as chemokine (CXC) receptor 2 (CXCR2) antagonists reduce neutrophils, but do not improve clinical outcomes in studies to date. Inhaled phosphodiesterase (PDE)4 inhibitors, dual PDE3 and PDE4 inhibitors, p38MAPK (mitogen-activated protein kinase) inhibitors, tyrosine kinase inhibitors and PI (phosphoinositide) 3kinase inhibitors are under development and these compounds may be of benefit in noneosinophilic inflammation. The results of clinical trials of biological agents targeting mediators associated with noneosinophilic inflammation, such as interleukin (IL)-17 and tumor necrosis factor (TNF)-α are disappointing. Greater understanding of the mechanisms of noneosinophilic inflammation in asthma should lead to improved therapies.

Vitamin D3 for uncontrolled childhood asthma: A pilot study

BACKGROUND

Observational and mechanistic data suggest a role for vitamin D in childhood asthma. However, subsequent interventional trials have been inconsistent. We aimed to assess the effect of 15 weeks of vitamin D3 supplementation compared with placebo (PL) in Irish children with asthma.

METHODS

We conducted a double-blind, randomized, PL-controlled trial of vitamin D supplementation (2000 IU/day) in 44 urban, Caucasian children at high latitude. Assessments were completed at baseline and after 15 weeks of supplementation. Outcome measures were lung function, subjective asthma control and biochemical parameters of total vitamin D, allergy, immunity, airway inflammation, and systemic inflammation. Finally, parents/guardians completed a weekly diary during the trial.

RESULTS

There was no significant difference in baseline 25(OH)D levels, but there was a significant increase in median 25(OH)D in the vitamin D3 group (57.5-105 nmol/l) compared with the PL group (52.5-57.5 nmol/l) (p < 0.0001). There was no significant difference between groups regarding subjective asthma control. Compared with PL, there was a significant decrease in school days missed due to asthma (1 vs. 5 days, p = 0.04) and alkaline phosphatase (-3.4 vs. +16; p = 0.037) in the vitamin D3 group, but there were no beneficial effects regarding several other secondary end-points. However, there were non-significant, advantageous changes in the PL group compared with the vitamin D3 group in subjective asthma control and lung function, particularly percentage of predicted forced expiratory volume in 1 s (+2.5 vs. -4; p = 0.06).

CONCLUSION

Vitamin D3 supplementation led to a significant increase in serum 25(OH)D and decreased school days missed (p = 0.04), but no other advantageous changes in asthma parameters compared with PL. The potential adverse effect of vitamin D deficiency on growth and the potential negative effect of high serum 25(OH)D on pulmonary function warrant further investigation.

Identification of vitamin D sensitive pathways during lung development

BACKGROUND

We have previously shown that vitamin D deficiency has a detrimental impact on lung development. In this study, we aimed to identify the mechanisms linking vitamin D with lung development using a mouse model of dietary manipulation.

METHODS

Female offspring were euthanized at different time-points; embryonic day (E)14.5, E17.5 or postnatal day (P)7. Lung tissue was collected for mass spectrometry-based proteomic analysis. Label-free quantitation was used to identify the differentially expressed proteins and ELISA confirmed the expression of selected proteins. Lungs from separate groups of mice were fixed and processed for stereological assessment of lung structure.

RESULTS

No differences in protein expression between vitamin D deficient and replete mice were detected at E14.5 and E17.5, whereas 66 proteins were differentially expressed in P7 lungs. The expression of pulmonary surfactant-associated protein B (SP-B) and peroxiredoxin 5 (PRDX5) were reduced in P7 lungs of vitamin D deficient mice, while the production of collagen type Ι alpha 1 (COL1A1) was higher in lungs of vitamin D deficient mice. There were no differences in lung volume, parenchymal volume, volume of airspaces or surface area of airspaces between vitamin D deficient and vitamin D replete mice across three time-points.

CONCLUSIONS

The difference in protein expression during the early postnatal time-point suggests that vitamin D deficiency may induce alterations of lung structure and function in later life during alveolarization stage through impaired pulmonary surfactant production and anti-oxidative stress ability as well as enhanced collagen synthesis. These data provided a plausible mechanism linking maternal vitamin D deficiency with altered postnatal lung function.

Vitamin D and Lung Function Decline in Adults With Asthma: The HUNT Study

We investigated whether low 25-hydroxyvitamin D (25(OH)D) levels were associated with more lung function decline in adults with asthma and whether this association was modified by smoking status or inhaled corticosteroid (ICS) use. We analyzed data on 395 adults with asthma from the Nord-Trøndelag Health Study (1995-2008), Norway. Plasma 25(OH)D and lung function were measured at baseline, and lung function measurements were repeated at follow-up, approximately 11 years later. Linear regression was used to estimate lung function decline. Participants with low 25(OH)D (<50 nmol/L) had more decline in lung function measurements for forced expiratory volume in 1 second (FEV1) (388 mL), forced vital capacity (298 mL), and the FEV1/forced vital capacity ratio (3.7%) over the follow-up, compared with those with high 25(OH)D (≥50 nmol/L) who declined 314 mL, 246 mL, and 3.0%, respectively (P = 0.08, 0.30, and 0.23, respectively). The associations were stronger in never smokers and non-ICS users. In never smokers, low 25(OH)D levels were associated with more decline in FEV1 (445 vs. 222 mL) (P = 0.01). In non-ICS users, low 25(OH)D levels were associated with more decline in FEV1 (467 vs. 320 mL) (P = 0.02). Low serum 25(OH)D levels were weakly associated with more lung function decline in adults with asthma, and stronger associations were observed in never smokers and non-ICS users.

Asthma and dietary intake: an overview of systematic reviews

Epidemiological research on the relationship between diet and asthma has increased in the last decade. Several components found in foods have been proposed to have a series of antioxidant, anti-allergic and anti-inflammatory properties, which can have a protective effect against asthma risk. Several literature reviews and critical appraisals have been published to summarize the existing evidence in this field. In the context of this EAACI Lifestyle and asthma Task Force, we summarize the evidence from existing systematic reviews on dietary intake and asthma, using the PRISMA guidelines. We therefore report the quality of eligible systematic reviews and summarize the results of those with an AMSTAR score ≥32. The GRADE approach is used to assess the overall quality of the existing evidence. This overview is centred on systematic reviews of nutritional components provided in the diet only, as a way to establish what type of advice can be given in clinical practice and to the general population on dietary habits and asthma.

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.

Vitamin D and asthma: current perspectives

PURPOSE OF REVIEW

To review the current evidence on the relationship between vitamin D and asthma.

RECENT FINDINGS

The rising morbidity and tremendous socioeconomic burden of asthma have prompted efforts to seek modifiable environmental and nutritional factors that contribute to the asthma epidemic. The association between low levels of vitamin D and asthma has been supported by many, but not all observational and epidemiologic studies. Recently, several controlled clinical trials have been undertaken to explore the effect of vitamin D supplementation on asthma control and respiratory tract infections. While some trials support the beneficial role of vitamin D supplementation in reducing asthma severity in children, several trials have found no beneficial role in adults.

SUMMARY

Given the high prevalence of vitamin D insufficiency in children and adults worldwide and recent randomized controlled trials of vitamin D in asthma, supplementation with vitamin D cannot be recommended as adjunctive therapy for asthma.

A review of Vitamin D effects on common respiratory diseases: Asthma, chronic obstructive pulmonary disease, and tuberculosis

Despite the classic role of Vitamin D in skeletal health, new aspects of Vitamin D have been discovered in tissues and organs other than bones. Epidemiological and observational studies demonstrate a link between Vitamin D deficiency and risk of developing respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD), and tuberculosis (TB). To review the literature, we searched the terms "Vitamin D" (using the set operator) and "asthma," "COPD" and "TB" in electronic databases, including PubMed/MEDLINE, Scopus, and Google Scholar until July 2015. Non-English articles or articles with unavailable full text were excluded. Both in vivo and in vitro studies were included. All the reviewed articles state that Vitamin D deficiency is very common among patients with respiratory diseases. The present data regarding Vitamin D and asthma is still controversial, but data about COPD and TB are more encouraging. The relevant studies have been conducted in different populations therefore it is not particularly possible to compare the data due to genetic variations. In order to point out a role for Vitamin D, large clinical trials with Vitamin D deficient subjects and sufficient Vitamin D supplementation are needed.

Vitamin D Supplementation and the Risk of Colds in Patients with Asthma

RATIONALE

Restoration of vitamin D sufficiency may reduce asthma exacerbations, events that are often associated with respiratory tract infections and cold symptoms.

OBJECTIVES

To determine whether vitamin D supplementation reduces cold symptom occurrence and severity in adults with mild to moderate asthma and vitamin D insufficiency.

METHODS

Colds were assessed in the AsthmaNet VIDA (Vitamin D Add-on Therapy Enhances Corticosteroid Responsiveness) trial, in which 408 adult patients were randomized to receive placebo or cholecalciferol (100,000 IU load plus 4,000 IU/d) for 28 weeks as add-on therapy. The primary outcome was cold symptom severity, which was assessed using daily scores on the 21-item Wisconsin Upper Respiratory Symptom Survey.

MEASUREMENTS AND MAIN RESULTS

A total of 203 participants experienced at least one cold. Despite achieving 25-hydroxyvitamin D levels of 41.9 ng/ml (95% confidence interval [CI], 40.1-43.7 ng/ml) by 12 weeks, vitamin D supplementation had no effect on the primary outcome: the average peak WURSS-21 scores (62.0 [95% CI, 55.1-68.9; placebo] and 58.7 [95% CI, 52.4-65.0; vitamin D]; P = 0.39). The rate of colds did not differ between groups (rate ratio [RR], 1.2; 95% CI, 0.9-1.5); however, among African Americans, those receiving vitamin D versus placebo had an increased rate of colds (RR, 1.7; 95% CI, 1.1-2.7; P = 0.02). This was also observed in a responder analysis of all subjects achieving vitamin D sufficiency, regardless of treatment assignment (RR, 1.4; 95% CI, 1.1-1.7; P = 0.009).

CONCLUSIONS

Our findings in patients with mild to moderate asthma undergoing an inhaled corticosteroid dose reduction do not support the use of vitamin D supplementation for the purpose of reducing cold severity or frequency.

Endotoxin exposure, serum vitamin D, asthma and wheeze outcomes

BACKGROUND

Endotoxin has been shown to induce neutrophilic asthma and wheeze after binding toll-like receptor 4 to produce pro-inflammatory cytokines. Animal models have demonstrated that vitamin D might inhibit lipopolysaccharide-induced cytokines. However, whether endotoxin exposure and serum vitamin D deficiency interact to affect asthma and wheeze in humans has never been investigated in an epidemiological study.

METHODS

Joint associations of house dust endotoxin and vitamin D with asthma and wheeze were examined using logistic regression adjusted for covariates in 5924 US participants of the National Health and Nutrition Examination Survey (NHANES). Interactions were assessed on the multiplicative as well as additive scale using the relative excess risk, the attributable portion due to additive interaction, and the synergy index.

RESULTS

The median endotoxin concentration was 19.1 EU/mg. Prevalence of vitamin D inadequacy (20-30 ng/ml) and deficiency (<20 ng/ml) were respectively 42.9 and 33.4%. The combination of high endotoxin and low vitamin D was associated with current asthma (OR: 1.56, 95% CI: 1.09, 2.23), wheeze in the past 12 months (OR: 1.72, 95% CI: 1.10, 3.71), recurrent wheeze (OR: 1.97, 95% CI: 1.00, 4.00), asthma diagnosis or recurrent wheeze (OR: 1.88, 95% CI: 1.33, 2.66), and current asthma or recurrent wheeze (OR:1.81, 95% CI: 1.23, 2.68) when compared to low endotoxin and normal vitamin D. The interactions between the exposures were not significant on the multiplicative or additive scale for any of the outcomes.

CONCLUSIONS

Combination of high endotoxin exposure and low vitamin D increases the odds of asthma and wheeze, but the exposures do not interact or modify each other's effect in the NHANES cohort.

Vitamin D supplementation protects against bone loss following inhalant organic dust and lipopolysaccharide exposures in mice

Systemic bone loss is associated with airway inflammatory diseases; yet, strategies to halt disease progression from inhalant exposures are not clear. Vitamin D might be a potentially protective approach against noxious respirable environmental exposures. We sought to determine whether vitamin D supplementation represents a viable lung- and bone-protective strategy following repetitive inhalant treatments with organic dust extract (ODE) or lipopolysaccharide (LPS) in mice. C57BL/5 mice were maintained on diets with low (1 IU/D/g) or high (10 IU/D/g) vitamin D for 5 weeks and treated with ODE from swine confinement facilities, LPS, or saline daily for 3 weeks per established intranasal inhalation protocol. Lungs, hind limbs, and sera were harvested for experimental outcomes. Serum 25-hydroxyvitamin D levels were tenfold different between low and high vitamin D treatment groups with no differences between inhalant agents and saline treatments. Serum calcium levels were not affected. There was no difference in the magnitude of ODE- or LPS-induced inflammatory cell influx or lung histopathology between high and low vitamin D treatment groups. However, high vitamin D treatment reversed the loss of bone mineral density, bone volume, and bone micro-architecture deterioration induced by ODE or LPS as determined by micro-CT analysis. Bone-resorbing osteoclasts were also reduced by high vitamin D treatment. In the low vitamin D treatment groups, ODE induced the greatest degree of airway inflammatory consequences, and LPS induced the greatest degree of bone loss. Collectively, high-concentration vitamin D was protective against systemic bone loss, but not airway inflammation, resulting from ODE- or LPS-induced airway injury.

Challenges and Current Efforts in the Development of Biomarkers for Chronic Inflammatory and Remodeling Conditions of the Lungs

This review discusses biomarkers that are being researched for their usefulness to phenotype chronic inflammatory lung diseases that cause remodeling of the lung's architecture. The review focuses on asthma, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension. Bio-markers of environmental exposure and specific classes of biomarkers (noncoding RNA, metabolism, vitamin, coagulation, and microbiome related) are also discussed. Examples of biomarkers that are in clinical use, biomarkers that are under development, and biomarkers that are still in the research phase are discussed. We chose to present examples of the research in biomarker development by diseases, because asthma, COPD, and pulmonary hypertension are distinct entities, although they clearly share processes of inflammation and remodeling.

Integrative medical approaches to allergic rhinitis

PURPOSE OF REVIEW

Complementary and integrative medicine (CIM), formerly known as alternative medicine, is now part of the mainstream management for patients with a host of medical issues. This current opinion focuses on the use of CIM, more specifically, the use of nutritional and herbal therapies and homeopathic medications for patients with allergic symptoms.

RECENT FINDINGS

The literature review revealed that naturally occurring substances when compared with placebo more often than not resulted in significant improvement of the allergic rhinitis symptoms.

SUMMARY

Despite encouraging results, additional studies with greater rigor are needed.

Vitamin D Supplementation Reduces Induction of Epithelial-Mesenchymal Transition in Allergen Sensitized and Challenged Mice

Asthma is a chronic disease of the lung associated with airway hyperresponsiveness (AHR), airway obstruction and airway remodeling. Airway remodeling involves differentiation of airway epithelial cells into myofibroblasts via epithelial-mesenchymal transition (EMT) to intensify the degree of subepithelial fibrosis. EMT involves loss in E-cadherin with an increase in mesenchymal markers, including vimentin and N-cadherin. There is growing evidence that vitamin D has immunomodulatory and anti-inflammatory properties. However, the underlying molecular mechanisms of these effects are still unclear. In this study, we examined the contribution of vitamin D on the AHR, airway inflammation and expression of EMT markers in the airways of mice sensitized and challenged with a combination of clinically relevant allergens, house dust mite, ragweed, and Alternaria (HRA). Female Balb/c mice were fed with vitamin D-sufficient (2000 IU/kg) or vitamin D-supplemented (10,000 IU/kg) diet followed by sensitization with HRA. The density of inflammatory cells in the bronchoalveolar lavage fluid (BALF), lung histology, and expression of EMT markers by immunofluorescence were examined. Vitamin D-supplementation decreased AHR, airway inflammation in the BALF and the features of airway remodeling compared to vitamin D-sufficiency in HRA-sensitized and -challenged mice. This was accompanied with increased expression of E-cadherin and decreased vimentin and N-cadherin expression in the airways. These results indicate that vitamin D may be a beneficial adjunct in the treatment regime in allergic asthma.

The effects of in utero vitamin D deficiency on airway smooth muscle mass and lung function

We have previously demonstrated increased airway smooth muscle (ASM) mass and airway hyperresponsiveness in whole-life vitamin D-deficient female mice. In this study, we aimed to uncover the molecular mechanisms contributing to altered lung structure and function. RNA was extracted from lung tissue of whole-life vitamin D-deficient and -replete female mice, and gene expression patterns were profiled by RNA sequencing. The data showed that genes involved in embryonic organ development, pattern formation, branching morphogenesis, Wingless/Int signaling, and inflammation were differentially expressed in vitamin D-deficient mice. Network analysis suggested that differentially expressed genes were connected by the hubs matrix metallopeptidase 9; NF-κ light polypeptide gene enhancer in B cells inhibitor, α; epidermal growth factor receptor; and E1A binding protein p300. Given our findings that developmental pathways may be altered, we investigated if the timing of vitamin D exposure (in utero vs. postnatal) had an impact on lung health outcomes. Gene expression was measured in in utero or postnatal vitamin D-deficient mice, as well as whole-life vitamin D-deficient and -replete mice at 8 weeks of age. Baseline lung function, airway hyperresponsiveness, and airway inflammation were measured and lungs fixed for lung structure assessment using stereological methods and quantification of ASM mass. In utero vitamin D deficiency was sufficient to increase ASM mass and baseline airway resistance and alter lung structure. There were increased neutrophils but decreased lymphocytes in bronchoalveolar lavage. Expression of inflammatory molecules S100A9 and S100A8 was mainly increased in postnatal vitamin D-deficient mice. These observations suggest that in utero vitamin D deficiency can alter lung structure and function and increase inflammation, contributing to symptoms in chronic diseases, such as asthma.

What diseases are causally linked to vitamin D deficiency?

The classical clinical consequence of vitamin D deficiency is osteomalacia, presenting as rickets in children. This remains a common problem in parts of the Middle East and the Indian subcontinent, and occurs when serum 25-hydroxyvitamin D levels are <25 nmol/L. Osteomalacia remains the only problem that is unequivocally a consequence of vitamin D deficiency. Low levels of 25-hydroxyvitamin D are observed in a wide range of conditions, but consistent trial evidence of amelioration of these conditions with vitamin D is lacking. Monotherapy with vitamin D has not been found to be effective in meta-analyses of trials assessing its effects on bone density, fractures or falls. At present, supplements should be advised for individuals at risk of having serum 25-hydroxyvitamin D levels in the 25-40 nmol/L range, or below, with a view to prevention of osteomalacia.

Gastro-oesophageal reflux and worse asthma control in obese children: a case of symptom misattribution?

BACKGROUND

Obese children for unknown reasons report greater asthma symptoms. Asthma and obesity both independently associate with gastro-oesophageal reflux symptoms (GORS). Determining if obesity affects the link between GORS and asthma will help elucidate the obese-asthma phenotype.

OBJECTIVE

Extend our previous work to determine the degree of associations between the GORS and asthma phenotype.

METHODS

We conducted a cross-sectional study of lean (20%-65% body mass index, BMI) and obese (≥95% BMI) children aged 10-17 years old with persistent, early-onset asthma. Participants contributed demographics, GORS and asthma questionnaires and lung function data. We determined associations between weight status, GORS and asthma outcomes using multivariable linear and logistic regression. Findings were replicated in a second well-characterised cohort of asthmatic children.

RESULTS

Obese children had seven times higher odds of reporting multiple GORS (OR=7.7, 95% CI 1.9 to 31.0, interaction p value=.004). Asthma symptoms were closely associated with GORS scores in obese patients (r=0.815, p<0.0001) but not in leans (r=0.291, p=0.200; interaction p value=0.003). Higher GORS scores associated with higher FEV1-per cent predicted (p=0.003), lower airway resistance (R10, p=0.025), improved airway reactance (X10, p=0.005) but significantly worse asthma control (Asthma Control Questionnaire, p=0.007). A significant but weaker association between GORS and asthma symptoms was seen in leans compared with obese in the replicate cohort.

CONCLUSION

GORS are more likely to associate with asthma symptoms in obese children. Better lung function among children reporting gastro-oesophageal reflux and asthma symptoms suggests that misattribution of GORS to asthma may be a contributing mechanism to excess asthma symptoms in obese children.

Addressing corticosteroid insensitivity in adults with asthma

Corticosteroids are the most effective treatment for asthma, but the therapeutic response varies markedly between individuals, with up to one third of patients showing evidence of insensitivity to corticosteroids. This article summarizes information on genetic, environmental and asthma-related factors as well as demographic and pharmacokinetic variables associated with corticosteroid insensitivity in asthma. Molecular mechanisms proposed to explain corticosteroid insensitivity are reviewed including alterations in glucocorticoid receptor subtype, binding and nuclear translocation, increased proinflammatory transcription factors and defective histone acetylation. Current therapies and future interventions that may restore corticosteroid sensitivity in asthma are discussed, including small molecule drugs and biological agents. In the future, biomarkers may be used in the clinic to predict corticosteroid sensitivity in patients with poorly controlled asthma.

Lung VITAL: Rationale, design, and baseline characteristics of an ancillary study evaluating the effects of vitamin D and/or marine omega-3 fatty acid supplements on acute exacerbations of chronic respiratory disease, asthma control, pneumonia and lung function in adults

Laboratory and observational research studies suggest that vitamin D and marine omega-3 fatty acids may reduce risk for pneumonia, acute exacerbations of respiratory diseases including chronic obstructive lung disease (COPD) or asthma, and decline of lung function, but prevention trials with adequate dosing, adequate power, and adequate time to follow-up are lacking. The ongoing Lung VITAL study is taking advantage of a large clinical trial-the VITamin D and OmegA-3 TriaL (VITAL)--to conduct the first major evaluation of the influences of vitamin D and marine omega-3 fatty acid supplementation on pneumonia risk, respiratory exacerbation episodes, asthma control and lung function in adults. VITAL is a 5-year U.S.-wide randomized, double-blind, placebo-controlled, 2 × 2 factorial trial of supplementation with vitamin D3 ([cholecalciferol], 2000 IU/day) and marine omega-3 FA (Omacor® fish oil, eicosapentaenoic acid [EPA]+docosahexaenoic acid [DHA], 1g/day) for primary prevention of CVD and cancer among men and women, at baseline aged ≥50 and ≥55, respectively, with 5107 African Americans. In a subset of 1973 participants from 11 urban U.S. centers, lung function is measured before and two years after randomization. Yearly follow-up questionnaires assess incident pneumonia in the entire randomized population, and exacerbations of respiratory disease, asthma control and dyspnea in a subpopulation of 4314 randomized participants enriched, as shown in presentation of baseline characteristics, for respiratory disease, respiratory symptoms, and history of cigarette smoking. Self-reported pneumonia hospitalization will be confirmed by medical record review, and exacerbations will be confirmed by Center for Medicare and Medicaid Services data review.

1,25D3 prevents CD8(+)Tc2 skewing and asthma development through VDR binding changes to the Cyp11a1 promoter

Effector CD8⁺ T cells convert from IFN-γ⁺ (Tc1) to IL-13⁺ (Tc2) cells in the presence of IL-4. Underlying regulatory mechanisms are not fully defined. Here, we show that addition of 1,25D3, the active form of vitamin D3, during CD8⁺ T-cell differentiation prevents IL-4-induced conversion to IL-13-producers. Transfer of 1,25D3-treated CD8⁺ T cells into sensitized and challenged CD8⁺-deficient recipients fails to restore development of lung allergic responses. 1,25D3 alters vitamin D receptor (VDR) recruitment to the Cyp11a1 promoter in vitro and in vivo in the presence of IL-4. As a result, protein levels and enzymatic activity of CYP11A1, a steroidogenic enzyme regulating CD8⁺ T-cell conversion, are decreased. An epistatic effect between CYP11A1 and VDR polymorphisms may contribute to the predisposition to childhood asthma. These data identify a role for 1,25D3 in the molecular programming of CD8⁺ T-cell conversion to an IL-13-secreting phenotype through regulation of steroidogenesis, potentially governing asthma susceptibility.

Type 2 CD8⁺ T cells (Tc2) play a role in the development of experimental asthma. Here the authors show that 1,25D3, the active form of vitamin D3, can prevent conversion of CD8⁺T cells to a Tc2 phenotype, reducing asthma susceptibility.