Link between vitamin D and airway remodeling

Vitamin D impedes eosinophil chemotaxis via inhibiting glycolysis-induced CCL26 expression in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is likely to relapse due to aberrant eosinophil infiltration. The deficiency of Vitamin D (VD) is associated with increased eosinophil infiltration in eosinophilic oesophagitis. However, the role of VD in eosinophilic CRSwNP (ECRSwNP) remains unclear. This study aims to explore the effects of VD on eosinophil chemotaxis in ECRSwNP and the underlying mechanisms.

METHODS

Human nasal mucosal tissues were collected from the control group, patients with non-ECRSwNP and those with ECRSwNP. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression of VD and CCL26 in the nasal mucosa, plasma, or human primary nasal epithelial cells (hNECs). hNECs and eosinophils from patients were cultured to investigate the effect of VD on eosinophil chemotaxis and CCL26 expression via eosinophil migration assay, Western blot, and ELISA. Transcriptome sequencing, pathway enrichment analysis, Western blot and immunohistochemical staining were used to determine the key signaling pathway involved in eosinophil chemotaxis.

RESULTS

A significant decrease in VD levels was observed in the nasal mucosa of patients with ECRSwNP, which correlated with increased local eosinophil infiltration. Furthermore, pathway enrichment analysis suggested that glycolysis signaling was promoted in the ECRSwNP group, verified by enhanced expression of glycolytic key enzymes that were positively correlated with eosinophil infiltration in nasal mucosa from patients with ECRSwNP. VD suppressed eosinophil chemotaxis in vitro by inhibiting CCL26 expression. Glycolysis regulated CCL26 expression via the ERK pathway and lactate, which promoted the expression and stability of CCL26 protein. VD attenuated glycolysis, leading to decreased production of lactate and inactivation of the ERK pathway. The decrease in lactate production suppressed eosinophil chemotaxis. Moreover, the ERK pathway activator reversed the inhibitory effect of VD on eosinophil chemotaxis.

CONCLUSIONS

VD impedes eosinophil chemotaxis by inhibiting glycolysis - induced CCL26 expression via attenuating the activation of the ERK pathway and reducing lactate production. VD supplementation may be a novel strategy to treat ECRSwNP.

Factors influencing stunted growth in children: A study in Bandung regency focusing on a deworming program

The prevalence of neglected tropical diseases, specifically those caused by soil-transmitted helminths (STHs) and other parasites that infest the intestine as part of their life cycle, remains a problem in Indonesia. We assessed the effects of deworming programs and socioeconomic and ecological factors on the incidence rate of infections with STHs and other parasites in an urban area of the Bandung Regency. We recruited 361 children with stunted growth who met the inclusion criteria, and 48 of those children were at high risk of STH infection. The study was conducted between September 2020 and September 2021. We collected possible socioeconomic factors influencing the incidence rate of infections. We found the incidence rate of STH infections among the children with stunted growth to be 3.6%. We confirmed infections with Cyclospora and Cryptosporidium after a Ziehl-Nieelsen stool smear examination in two of the 48 children at risk of infection. We found 43.75% of the children had short stature and weight below the normal limits, while stunting and severe stunting were associated with Ascaris lumbricoides infection (44.70%, p = 0.035). Parents of children with stunted and severely stunted growth were more likely to have a low education level, lack knowledge about deworming program, and to be earning a low income. The mother's occupation had a particularly strong influence on the severity of the stunting (89.58%, p = 0.012). Our results show that deworming programs can affect the growth and development of children and that socioeconomic and ecological factors also play a role.

Assessing the genetic relationship between gastroesophageal reflux disease and chronic respiratory diseases: a mendelian randomization study

BACKGROUND

Previous observational studies have found an association between gastroesophageal reflux disease (GERD) and chronic respiratory diseases, but it remains uncertain whether GERD causally influences these diseases. In this study, we aimed to estimate the causal associations between GERD and 5 chronic respiratory diseases.

METHODS

88 GERD-associated single nucleotide polymorphisms (SNPs) identified by the latest genome-wide association study were included as instrumental variables. Individual-level genetic summary data of participants were obtained from corresponding studies and the FinnGen consortium. We applied the inverse-variance weighted method to estimate the causality between genetically predicted GERD and 5 chronic respiratory diseases. Furthermore, the associations between GERD and common risk factors were investigated, and mediation analyses were conducted using multivariable MR. Various sensitivity analyses were also performed to verify the robustness of the findings.

RESULTS

Our study demonstrated that genetically predicted GERD was causally associated with an increased risk of asthma (OR 1.39, 95%CI 1.25-1.56, P < 0.001), idiopathic pulmonary fibrosis (IPF) (OR 1.43, 95%CI 1.05-1.95, P = 0.022), chronic obstructive disease (COPD) (OR 1.64, 95%CI 1.41-1.93, P < 0.001), chronic bronchitis (OR 1.77, 95%CI 1.15-2.74, P = 0.009), while no correlation was observed for bronchiectasis (OR 0.93, 95%CI 0.68-1.27, P = 0.645). Additionally, GERD was associated with 12 common risk factors for chronic respiratory diseases. Nevertheless, no significant mediators were discovered.

CONCLUSIONS

Our study suggested that GERD was a causal factor in the development of asthma, IPF, COPD and chronic bronchitis, indicating that GERD-associated micro-aspiration of gastric contents process might play a role in the development of pulmonary fibrosis in these diseases.

Asthma and Vitamin D Deficiency: Occurrence, Immune Mechanisms, and New Perspectives

Asthma, as a chronic inflammatory condition of the airways, has a considerable prevalence among children. Vitamin D might play a role in asthma pathogenesis by affecting the development of the lung, regulating the immune responses, and remodeling of airway smooth muscle (ASM). Study results on the association between the serum level of vitamin D and asthma severity have suggested a converse relationship between lower vitamin D levels and more severe clinical courses. However, they are not consistent in these findings and have shown insignificant correlations, as well. The possible effects of vitamin D on asthma have led researchers to consider this vitamin a potential prophylactic and therapeutic tool for managing children with variant degrees of asthma. Adding vitamin D to the routine corticosteroid therapy of asthmatic children is another field of interest that has shown promising results. In this narrative review study, we aim to elaborate on the existing knowledge on the role of vitamin D in asthma pathogenesis and prognosis, explain the controversies that exist on the effectiveness of treating patients with vitamin D supplements, and make a general conclusion about how vitamin D actually is linked to asthma in children.

A Meta-Analysis on Vitamin D Supplementation and Asthma Treatment

Background

Vitamin D, as an immunomodulator, may be related to the therapeutic effect of asthma patients, but the research in this area is still controversial. The aim of this meta-analysis was to analyze the role of vitamin D supplementation in the treatment of asthma patients.

Materials and Methods

Randomized Controlled Trials (RCTs) of vitamin D supplementation in asthma were searched in PubMed, EMBASE, and the Cochrane library. Primary outcomes were forced expiratory volume in one second (FEV1), asthma exacerbations, Asthma Control Test scores (ACT scores), and fractional exhaled nitric oxide (FENO).

Results

A total of 10 RCTs were included, including 1,349 patients. Vitamin D supplementation didn't affect the ACT scores (SMD = 0.04, 95% CI = -0.13 to 0.21, P = 0.87), FEV1 (SMD = 0.04, 95% CI = -0.35 to 0.43, P < 0.01) and FENO (SMD = -0.01, 95% CI = -0.22 to 0.20, P = 0.27), but reduced the rate of asthma exacerbations (RR = 0.69, 95% CI = 0.41 to 0.88, P < 0.01), especially in subgroups of children (RR = 0.46, 95% CI = 0.30 to 0.70, P = 0.83) and follow up time less than 6 months (RR = 0.45, 95% CI = 0.32 to 0.63, P = 0.95). Additionally, though there was only one study included in the subgroup, it significantly enhanced FEV1 at the last visit for patients whose FEV1 baseline value was less than 70% (SMD = 0.94, 95% CI = 0.47 to 1.41).

Conclusion

Vitamin D supplementation can reduce asthma exacerbations, especially in children, and within 6 months of follow up time. In addition, vitamin D has a positive effect on improving FEV1 of patients whose FEV1 baseline value is less than 70%, but more RCTs are still needed to support this conclusion.

Systematic Review Registration

[https://inplasy.com], identifier [10.37766/inplasy20 22.6.0049].

Decreased lung function is associated with vitamin D deficiency in apparently health, middle aged Koreans: the Kangbuk Samsung Health Study

BACKGROUND/OBJECTIVES

There has been inconsistent relationships between serum vitamin D levels and lung function in previous studies. However, previous studies included patients with medical diseases, affecting both vitamin D levels and lung function. Considering this view of potential confounders, we investigated if vitamin D deficiency (VDD) is linked to lung function in health screening examinee without overt medical conditions.

SUBJECTS/METHODS

We conducted a cohort study on 68,457 healthy Koreans (36,759 males, mean age: 37.7 years) with a health examination in 2015. Measured forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were categorized in quartiles. To examine the relationships between VDD and lung function, adjusted odds ratios (aORs) for VDD were estimated by logistic regression.

RESULTS

Median vitamin D level was 14.9 ng/mL. The prevalence of VDD (defined as <20 ng/ml) was 74.5%. Compared with the highest quartile (Q4, reference), the aORs for VDD across decreasing quartiles (from Q3 to Q1) were 1.05, 1.06, 1.10 for FVC, and 1.07, 1.10, 1.10 for FEV1 (P for trend < 0.01 for both), in all subjects. Similarly, the aOR of having VDD for men also increased with decreasing quartiles of FVC and FEV1 in a dose-response manner (p for trend < 0.01 for both). However, neither FVC nor FEV1 was associated with VDD in women.

CONCLUSIONS

VDD was associated with decreased lung function in middle aged Korean men without overt medical conditions. VDD could be a modifiable risk factor for impaired lung function, in men but not in women.

Action of 1,25(OH)2D3 on Human Asthmatic Bronchial Fibroblasts: Implications for Airway Remodeling in Asthma

Background

Airway fibroblasts are major contributors to the histopathological feature of airway remodeling in asthma by their implication in the cell invasiveness and profibrogenic secretory phenotype observed in subepithelial fibrosis. 1,25 Dihydroxy vitamin D₃ (1,25(OH)₂D₃) is an important therapeutic agent that blocks many features of airway remodeling induced by profibrogenic mediators, such as transforming growth factor beta 1 (TGF-β1) or T helper type 1 inflammatory cytokines.

Objective

We hypothesized that 1,25(OH)₂D₃ opposes the TGF-β1 or tumor necrosis factor alpha (TNF-α)-Interleukin 1 beta (IL-1β) stimulation on airway fibroblast profibrogenic secretory phenotype observed in severe asthmatic patients. Our aim was to investigate the anti-fibrogenic effect of 1,25(OH)₂D₃ in TGF-β1 or TNF-α-IL-1β-stimulated human bronchial fibroblast cells (HBFCs) from severe asthmatic compared with non-asthmatic subjects.

Patients and Methods

All experiments were performed on primary HBFCs from asthmatic (DHBFCs, n=4) and non-asthmatic subjects (NHBFCs, n=4). mRNA expression and protein quantification of key fibrogenic markers were analyzed by RT-qPCR and ELISA, comparing HBFCs from asthmatic and non-asthmatic subjects. Vitamin D receptor (VDR) mRNA expression and its functionality in HBFCs were assessed by RT-qPCR. HBFCs proliferation was assessed by flow cytometry using BrdU-FITC/7AAD bivariate staining, while HBFCs apoptosis by Annexin V-FITC/7AAD.

Results

VDR is constitutively expressed in HBFCs and the addition of 1,25(OH)₂D₃ significantly increased mRNA expression of CYP24A1 (a direct VDRs’ target gene) in both HBFCs groups. DHBFCs cultured in the presence of TGF-β1 or TNF-α-IL-1β showed increased mRNA expression and protein secretion of fibrogenic markers when compared to NHBFCs. Additionally, we observed decreased mRNA expression of FN 1, LUM, BGN, MMP2, COL5A1, TIMP1 and CC-chemokines (CCL2, CCL5, CCL11) in response to 1,25(OH)₂D₃ addition to the TGF-β1 or TNF-α-IL-1β-stimulated HBFCs. Cell culture media obtained from TGF-β1 or TNF-α-IL-1β-stimulated DHBFCs showed decreased protein secretion (fibronectin 1, lumican, MCP1, RANTES and eotaxin-1) in response to 1,25(OH)₂D₃ when compared to NHBFCs. 1,25(OH)₂D₃ inhibited proliferation in TGF-β1-stimulated HBFCs through G0/G1 cell cycle arrest and these effects were not correlated with the induction of apoptosis.

Conclusion

DHBFCs under TGF-β1 or TNF-α-IL-1β stimulation showed higher fibrogenic capacity when compared to NHBFCs. 1,25(OH)₂D₃ significantly blocked these effects and highlight 1,25(OH)₂D₃ as a possible therapeutic target for severe asthma.

Immune induction of airway remodeling

Airway remodeling is accepted to be a determining component within the natural history of asthma. It is a phenomenon characterized by changes in the airways structures that marches in parallel with and can be influenced by airway inflammation, floating at the interface between both natural and adaptive immunity and physical and mechanical cells behavior. In this review we aimed to highlight the comprehensive, yet not exhaustive, evidences of how immune cells induce, regulate and adapt to the recognized markers of airway remodeling. Mucous cell hyperplasia, epithelial dysfunction and mesenchymal transition, extracellular matrix protein synthesis and restructuration, fibroblast to myofibroblast transition, airway smooth muscle proliferation, bioactive and contractile properties, and vascular remodeling encompass complex physiopathological mechanisms that can be induced, suppressed or regulated by different cellular and molecular pathways. Growth factors, cytokines, chemokines and adhesion molecules expressed or derived either from the immune network of cells infiltrating the asthmatic airways and involving T helper lymphocytes, immune lymphoid cells, dendritic cells, eosinophils, neutrophils, mast cells or by the structural components such as epithelial cells, fibroblasts, myocytes, airway smooth muscle cells concur with protein cellular matrix component and metalloproteases in modifying the airway structure in a detrimental way. The consequences in lung function decline, fixed airway obstruction and clinical severity of the disease suggest the possibility of identify among the immune molecular pathway of remodeling some biological parameters or signal pathway to be either a good tracer for monitoring the disease evolution or a target for hypothetical phenotypes and endotypes. In the era of personalized medicine, a biomarker of remodeling might predict a response to small-molecule inhibitors or biologicals potentially targeting a fundamental aspect of asthma pathogenesis that impacts on the low responsiveness to airway inflammation directed treatments.

Effect of vitamin D deficiency in Korean patients with acute respiratory distress syndrome

BACKGROUND/AIMS

Vitamin D modulates innate and adaptive immune responses, and vitamin D deficiency is associated with increased mortality in hospitalized patients with pneumonia. We evaluated the prevalence of vitamin D deficiency in Korean patients with acute respiratory distress syndrome (ARDS) and its effect on the clinical outcomes of ARDS.

METHODS

We retrospectively analyzed the data of 108 patients who had a measured serum level of 25-hydroxy vitamin D3 (25(OH)D3) at the time of diagnosis with ARDS. The clinical outcomes were evaluated based on 25(OH)D3 levels of 20 ng/mL and stratified by quartiles of 25(OH)D3 levels.

RESULTS

The mean age of patients was 59.4 years old; 77 (71.3%) were male. Vitamin D deficiency was found in 103 patients (95.4%). The mean 25(OH)D3 level was 8.3 ± 7.0 ng/mL. Neither in-hospital mortality (40.0% vs. 68.0%) nor 6-month mortality (40.0% vs. 71.8%) significantly differed between groups. There were no significant differences in 25(OH)D3 level between survivors (8.1 ± 7.6 ng/mL) and non-survivors (8.5 ± 6.8 ng/mL, p = 0.765). There were no trends toward a difference in mortality among quartiles of 25(OH)D3 levels. However, 25(OH)D3 levels were inversely related with length of hospital stay and intensive care unit stay among in-hospital survivors.

CONCLUSION

Vitamin D deficiency was prevalent in Korean patients with ARDS. However, levels of vitamin D were not associated with mortality. A large, prospective study is needed to evaluate the effects of vitamin D deficiency on clinical outcomes of ARDS.

Serum 25-hydroxyvitamin D levels in patients with skin diseases including psoriasis, infections, and atopic dermatitis

The pathogenetic role of vitamin D as well as its clinical correlation in inflammatory skin diseases is still uncertain. This study aimed to compare serum levels of 25(OH) vitamin D (calcidiol) in outpatients suffering from different skin diseases using the same laboratory method in one study. In routine serum samples of 1,532 patients from the previous 12 months we identified retrospectively 180 (mean age 49.4 years, 80 female, 100 male) and 205 (mean age 36.3 years, 116 female, 89 male) patients with psoriasis (PSO) and atopic dermatitis (AD), respectively. Clinical disease activity and quality of life was evaluated using Physicians Global Assessment Scores (PGA), Dermatology Life Quality Index (DLQI), and a Visual Analog Scale for pruritus in AD, respectively. The median 25(OH)D serum level of all patients (22.97 ng/mL, range 2.61–96.0, n = 1,461) was significantly lower in comparison to healthy controls (41.6 ng/mL, range 16.9–77.57, p < 0.0001, n = 71). In PSO and AD we measured 21.05 ng/mL (44% < 20 ng/mL) and 22.7 ng/mL (39% < 20 ng/mL), respectively (p = 0.152). Among all subgroups, patients with severe acute or chronic infectious skin diseases had the lowest median 25(OH)D serum levels (17.11 ng/mL, n = 94, 66% <20 ng/mL, p < 0,001 vs. AD, p = 0,007 vs. PSO). For PSO and AD there was no significant correlation between 25(OH)D levels and PGA scores and DLQI values, respectively, or the extent of pruritus in AD. 25(OH)D serum levels in inflammatory skin diseases might correlate more with the type of disease and the degree of inflammation than with clinical activity itself.

Dietary vitamin D3 deficiency exacerbates sinonasal inflammation and alters local 25(OH)D3 metabolism

RATIONALE

Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) have been shown to be vitamin D3 (VD3) deficient, which is associated with more severe disease and increased polyp size. To gain mechanistic insights into these observational studies, we examined the impact of VD3 deficiency on inflammation and VD3 metabolism in an Aspergillus fumigatus (Af) mouse model of chronic rhinosinusitis (Af-CRS).

METHODS

Balb/c mice were fed control or VD3 deficient diet for 4 weeks. Mice were then sensitized with intraperitoneal Af, and one week later given Af intranasally every three days for four weeks while being maintained on control or VD3 deficient diet. Airway function, sinonasal immune cell infiltrate and sinonasal VD3 metabolism profiles were then examined.

RESULTS

Mice with VD3 deficiency had increased Penh and sRaw values as compared to controls as well as exacerbated changes in sRaw when coupled with Af-CRS. As compared to controls, VD3 deficient and Af-CRS mice had reduced sinonasal 1α-hydroxylase and the active VD3 metabolite, 1,25(OH)2D3. Differential analysis of nasal lavage samples showed that VD3 deficiency alone and in combination with Af-CRS profoundly upregulated eosinophil, neutrophil and lymphocyte numbers. VD3 deficiency exacerbated increases in monocyte-derived dendritic cell (DC) associated with Af-CRS. Conversely, T-regulatory cells were decreased in both Af-CRS mice and VD3 deficient mice, though coupling VD3 deficiency with Af-CRS did not exacerbate CD4 or T-regulatory cells numbers. Lastly, VD3 deficiency had a modifying or exacerbating impact on nasal lavage levels of IFN-γ, IL-6, IL-10 and TNF-α, but had no impact on IL-17A.

CONCLUSIONS

VD3 deficiency causes changes in sinonasal immunity, which in many ways mirrors the changes observed in Af-CRS mice, while selectively exacerbating inflammation. Furthermore, both VD3 deficiency and Af-CRS were associated with altered sinonasal VD3 metabolism causing reductions in local levels of the active VD3 metabolite, 1,25(OH)2D3, even with adequate circulating levels.

Vitamin D and Cardiorespiratory Fitness in the General Population: A Systematic Review

Abstract. Background: Up to now, the association between vitamin D and cardiorespiratory fitness (CRF) is still inconsistent and there is a lack of a comprehensive review on this topic. Aim: To systematically review the literature including both observational studies and randomized controlled trials (RCTs) on the association between vitamin D and CRF in the general population. Methods: The literature was investigated by exploring databases of PubMed, EMBASE, Scopus and ISI Web of Science as well as a manual search up to April 2017 by using related MeSH terms and key words. All the English-language articles that were conducted in the general population without any restriction on age range of participants and date of publication were included in the study. Results: Among the 731 records which were found initially, a total of 20 articles including 18 cross-sectional studies and 2 RCTs fulfilled the inclusion criteria. Among the cross-sectional studies, findings on the association between serum 25(OH) D and CRF were incongruent. Additionally, studies which had reported significant results varied remarkably in terms of sample size, study population and the effect size of the association. In addition, RCTs found no significant improvement in CRF following vitamin D supplementation. Conclusion: Overall, evidence from cross-sectional studies does not support a strong association between vitamin D and CRF, although a number of studies demonstrated modest positive associations. Furthermore, limited RCTs did not confirm such an association. Further high quality research is needed to obtain a definite conclusion on this topic. “

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.

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 impact of vitamin D on asthmatic human airway smooth muscle

Asthma is a chronic heterogeneous disorder, which involves airway inflammation, airway hyperresponsiveness (AHR) and airway remodeling. The airway smooth muscle (ASM) bundle regulates the broncho-motor tone and plays a critical role in AHR as well as orchestrating inflammation. Vitamin D deficiency has been linked to increased severity and exacerbations of symptoms in asthmatic patients. It has been shown to modulate both immune and structural cells, including ASM cells, in inflammatory diseases. Given that current asthma therapies have not been successful in reversing airway remodeling, vitamin D supplementation as a potential therapeutic option has gained a great deal of attention. Here, we highlight the potential immunomodulatory properties of vitamin D in regulating ASM function and airway inflammation in bronchial asthma.

1α,25-dihydroxyvitamin D3 acts via transforming growth factor-β to up-regulate expression of immunosuppressive CD73 on human CD4+ Foxp3- T cells

Vitamin D deficiency is associated with increased incidence and severity of various immune-mediated diseases. Active vitamin D (1α,25-dihydroxyvitamin D3; 1,25(OH)2 D3) up-regulates CD4(+) T-cell expression of the purine ectonucleotidase CD39, a molecule that is associated with the generation of anti-inflammatory adenosine. Here we aimed to investigate the direct impact of 1,25(OH)2 D3 on expression of the downstream ecto-5'-nucleotidase CD73 by human CD4 T cells, and components of the transforming growth factor-β (TGF-β) pathway, which have been implicated in the modulation of CD73 by murine T cells. At 10(-8) to 10(-7) m, 1,25(OH)2 D3 significantly increased expression of CD73 on peripheral human CD4(+) T cells. Although 1,25(OH)2 D3 did not affect the mRNA expression of latent TGF-β1 , 1,25(OH)2 D3 did up-regulate expression of TGF-β-associated molecules [latency-associated peptide (LAP), glycophorin A repetitions predominant (GARP), GP96, neuropilin-1, thrombospondin-1 and αv integrin] which is likely to have contributed to the observed enhancement in TGF-β bioactivity. CD73 was highly co-expressed with LAP and GARP following 1,25(OH)2 D3 treatment, but unexpectedly, each of these cell surface molecules was expressed primarily on CD4(+) Foxp3(-) T cells, rather than CD4(+) Foxp3(+) T cells. Notably, neutralization of TGF-β significantly impaired 1,25(OH)2 D3-mediated induction of CD73. Collectively, we show that 1,25(OH)2 D3 enhances expression of CD73 on CD4(+) Foxp3(-) T cells in a process that is at least partially TGF-β-dependent. These data reveal an additional contributing mechanism by which vitamin D may be protective in immune-mediated disease.

Intercellular adhesion molecule-1 expression in activated eosinophils is associated with mucosal remodeling in nasal polyps

Nasal polyposis (NP) is characterized by chronic mucosal inflammation with infiltrating eosinophils. Eosinophil-mediated tissue remodeling may be involved in NP pathogenesis; therefore, improved understanding of tissue remodeling may result the identification of novel pathways and therapeutic strategies. The present study aimed to investigate the pathological changes occurring during tissue remodeling in NP, in order to assess the role of intercellular adhesion molecule-1 (ICAM-1) in localized tissue remodeling and the potential association between ICAM-1 expression and markers of eosinophil activation. A total of 28 eligible patients and 10 healthy controls participated in the current study. Nasal mucosal tissues of these subjects were retrospectively evaluated for mucosal remodeling using histopathological staining. ICAM-1 and eosinophil cationic protein (ECP) expression levels were determined by immunohistochemical analysis. Compared with the healthy controls, all the specimens from NP patients presented substantial epithelial damage, skewed cellular distribution with a reduced density of goblet cells, an increased density of subepithelial gland and increased subepithelial collagen deposition. In addition, the NP specimens exhibited significantly higher eosinophil infiltration and ICAM-1 expression compared with the controls. Positive correlations were observed between ICAM-1 and ECP expression levels (P=0.010), as well as between extracellular collagen deposition and ICAM-1 (P=0.010) and ECP (P=0.012) expression levels in the NP specimens, but not in the control specimens. Morphological evidence demonstrated eosinophil-mediated tissue remodeling in NP tissues. ICAM-1 expression in activated eosinophils was associated with NP remodeling, indicating the possibility that ICAM-1 may regulate NP remodeling.

Vitamin D regulating TGF-β induced epithelial-mesenchymal transition

Background

Subepithelial fibrosis is a characteristic hallmark of airway remodeling in asthma. A critical regulator of fibrosis, transforming growth factor β (TGF-β), can induce airway remodeling in epithelial cells through induction of epithelial-mesenchymal transition (EMT). Vitamin D has immunomodulatory functions, however, its effect on controlling subepithelial fibrosis is not known.

Methods

Human bronchial epithelial cells (BEAS-2B) were exposed to calcitriol followed by stimulation with TGF-β1 or TGF-β2. The protein expression and mRNA transcripts for E-cadherin, Snail, vimentin, and N-cadherin were analyzed by Western blot and qPCR. An invasion assay and scratch wound assay were performed to identify the migratory properties of the cells following treatments.

Results

TGF-β1 decreased E-cadherin expression and increased protein expression and mRNA transcripts of Snail, vimentin, and N-cadherin together with increased cell invasion and migration. TGF-β2 elicited migratory response similar to TGF-β1 but induced the expression of EMT markers differently from that by TGF-β1. Calcitriol attenuated TGF-β1- and TGF-β2-induced cell motility. Also, calcitriol inhibited the expression of EMT markers in TGF-β1-treated epithelial cells with less effect on TGF-β2.

Conclusions

These data suggest that calcitriol inhibits both migration and invasion induced by TGF-β1 and TGF-β2 in human airway epithelial cells. However, the regulatory effect of vitamin D in epithelial-mesenchymal transition was more effective to TGF-β1-induced changes. Thus, calcitriol could be a potential therapeutic agent in the prevention and management of subepithelial fibrosis and airway remodeling.

Vitamin d levels in children with bronchial asthma

INTRODUCTION

Bronchial Asthma is a common chronic inflammatory disorder of the airways in childhood. Vitamin-D, required for bone mineralization, is also a potent immune system regulator having a potential role in various allergic diseases. This study was undertaken to determine the difference in serum levels of Vitamin-D in asthmatic children and to determine the association between vitamin-D and asthma in children.

MATERIALS AND METHODS

This cross-sectional study included 88 (44 asthmatic children and 44 healthy controls) children aged between 5 and 13 y. Serum 25-hydroxy vitamin-D levels were determined and compared between the two groups. The association between vitamin-D levels and lung function was studied in the asthmatic children.

RESULTS

Serum vitamin-D level was significantly lower in asthmatic children than in control group and in the asthmatic group, vitamin-D levels had a significant positive correlation with FEV1% and FEV1/FVC%.

CONCLUSION

Vitamin-D deficiency is highly prevalent in asthmatic children and is associated with airway limitation.

An overview of integrative therapies in asthma treatment

Treatment of asthma lends itself to an integrative medicine approach due to the multifactorial nature of the disease. It is well established that asthma has a neuromuscular component (bronchospasm), an immunological component (inflammation), and a psychological component. This encourages the use of diverse approaches to address all avenues of pathophysiology, aiming for the most effective blend of treatment approaches possible. Integrative medicine is defined by NIH NCCAM ( http://nccam.nih.gov ) as medicine that blends the use of evidence-based complementary therapies with conventional medicine. Statistics from the 2007 National Health Interview Survey (NHIS), conducted by the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS), showed that approximately four out of 10 adults and approximately one in nine children and more than 50 % of children living with chronic illness, including asthma, used complementary therapies in the USA in 2007. Asthma and allergies rank among the top 15 most common medical conditions in which integrative therapies are used in both children and adults. To date, integrative treatment approaches with some evidence for benefit in asthma treatment include the following: nutrition modification, mind-body medicine, physical activity, and certain dietary supplement interventions.

Association of vitamin D receptor gene polymorphisms with asthma risk: systematic review and updated meta-analysis of case-control studies

BACKGROUND

The association between vitamin D receptor (VDR) polymorphisms and asthma risk has been inconsistently investigated, but published studies demonstrated conflicting results. The aim of the current study was to investigate the impact of TaqI, BsmI, ApaI, and FokI VDR polymorphisms on asthma disease by using a meta-analysis approach.

METHODS

Following the preferred reporting items for systematic reviews and meta-analyses guidelines, a systematic search and meta-analysis of the literature were conducted. Subgroup analyses were performed to detect potential sources of heterogeneity from selected study characteristics.

RESULTS

A total of 2,097 cases and 1,968 controls in eight case-control studies were included in meta-analyses. A significant association was found between TaqI polymorphisms and asthma risk [OR 1.488 (95 % CI 1.019-2.174); P = 0.040] in a codominant model. In the same way, BsmI was significantly associated with asthma risk [OR 2.017 (95 % CI 1.236-3.851); P = 0.017] in the codominant model. The homozygote BB BsmI genotype was found to confer significant asthma risk. FokI polymorphism was marginally associated with asthma risk [OR 1.187 (95 % CI 0.975-1.446); P = 0.088] in the codominant model. In contrast, no significant association was found between ApaI polymorphism and asthma risk. Subgroup analyses revealed that gender and age modified significantly the association between FokI polymorphisms and asthma risk (P = 0.035 and 0.013, respectively). Publication year and serum 25(OH) D level tended, marginally, to moderate the association between FokI polymorphism and asthma risk.

CONCLUSION

TaqI, BsmI, and FokI VDR polymorphisms contribute to asthma susceptibility. The association between FokI polymorphism and asthma risk is influenced by study characteristics.