Nonasthmatic Subjects Research Articles

Chlamydia pneumoniae-Induced IFN-Gamma Responses in Peripheral Blood Mononuclear Cells Increase Numbers of CD4+ but Not CD8+ T Effector Memory Cells.

BackgroundChlamydia pneumoniae causes respiratory infection in adults and children. Previous studies in our laboratory identified significantly higher in vitro T lymphocyte responses to C. pneumoniae in children with asthma compared to healthy controls which may indicate the presence of T effector memory (TEM) lymphocytes.AimIn the present study, healthy subjects were screened for the presence of TEM cells and their cytokines. CCR7 negative effector TEMs may indicate persistent infection with C. pneumoniae.MethodsPeripheral blood mononuclear cells (PBMC) (1×106/mL) from adult non-asthmatic subjects were infected for 1h ± C. pneumoniae TW-183 at a multiplicity of infection (MOI) = 0.1 and cultured (48 hrs). Distributions of lymphocytes (CD4+, CD8+) and TEM cells (CD4+CCR7+CD45RA+CD154+, CD8+CCR7+CD45RA+CD154+) were determined. Levels of intracellular interleukin (IL)-2, IL-4, and interferon (IFN)-gamma were measured (flow microfluorimetry); IFN-gamma was measured in supernatants (ELISA).ResultsC. pneumoniae infection led to a decrease in numbers of CD8+ TEM and CD8+CD154+ cells; CD4+TEM and CD4+CD154+ cells did not change. Numbers of TEM cells (CD4+IL-2+, CD8+ IL-2+) also decreased. However, number of TEM cells (CD4+IL4-+, CD8+ IL-4+) and (CD4+ IFN-gamma+, CD8+IFN-gamma+) did not change. When stratified according to IFN-gamma+ status, numbers of CD4+ IL-2+ and CD4+IL-4+ TEMs increased; CD8+IL-2+ and CD8+ IL-4+ TEMs decreased.ConclusionC. pneumoniae-induced PBMC IFN-gamma+ responses increased numbers of CD4+ IL-2+ and CD4+IL-4+ TEM cells, while CD8+IL-2+ and CD8+IL-4+ TEMs decreased. Production of IFN-gamma by C. pneumoniae infected PBMC should be further studied as a biomarker of persistent infection in humans.

Real Time Breath Analysis Using Portable Gas Chromatography for Adult Asthma Phenotypes.

Asthma is heterogeneous but accessible biomarkers to distinguish relevant phenotypes remain lacking, particularly in non-Type 2 (T2)-high asthma. Moreover, common clinical characteristics in both T2-high and T2-low asthma (e.g., atopy, obesity, inhaled steroid use) may confound interpretation of putative biomarkers and of underlying biology. This study aimed to identify volatile organic compounds (VOCs) in exhaled breath that distinguish not only asthmatic and non-asthmatic subjects, but also atopic non-asthmatic controls and also by variables that reflect clinical differences among asthmatic adults. A total of 73 participants (30 asthma, eight atopic non-asthma, and 35 non-asthma/non-atopic subjects) were recruited for this pilot study. A total of 79 breath samples were analyzed in real-time using an automated portable gas chromatography (GC) device developed in-house. GC-mass spectrometry was also used to identify the VOCs in breath. Machine learning, linear discriminant analysis, and principal component analysis were used to identify the biomarkers. Our results show that the portable GC was able to complete breath analysis in 30 min. A set of nine biomarkers distinguished asthma and non-asthma/non-atopic subjects, while sets of two and of four biomarkers, respectively, further distinguished asthmatic from atopic controls, and between atopic and non-atopic controls. Additional unique biomarkers were identified that discriminate subjects by blood eosinophil levels, obese status, inhaled corticosteroid treatment, and also acute upper respiratory illnesses within asthmatic groups. Our work demonstrates that breath VOC profiling can be a clinically accessible tool for asthma diagnosis and phenotyping. A portable GC system is a viable option for rapid assessment in asthma.

Cytokine Levels and Polymorphisms in Childhood Asthma Among the Iranian Population

Context: Chronic airway inflammation in asthma is affected by a complex network of interacting cytokines. The exact role of each cytokine in childhood asthma development has remained poorly understood. In this study, we aimed to review articles investigating cytokine levels and polymorphisms in childhood asthma among the Iranian population to assess susceptible cytokines related to childhood asthma. Evidence Acquisition: We performed a literature search in PubMed, Scopus, Science direct, and Embase databases to find articles that have evaluated the cytokine levels and gene polymorphisms in childhood asthma among the Iranian population until March 2, 2020. The terms used to search included “cytokine”, “interleukin”, “polymorphism”, “Asthma”, and “Iran” in the international databases. Only case-control studies with a healthy control group that investigated cytokine levels and polymorphism in childhood asthma among the Iranian population have been included. Results: Considering these criteria, we extracted 7 articles from international databases and included them in the current review. We investigated 4 cytokine levels and 4 cytokine polymorphism patterns in asthmatic and non-asthmatic subjects in Iran. Interleukin (IL)-23, IL-17, and IL-33 levels were statistically higher in asthmatic children, and also IL-33, IL-17 levels were associated with asthma severity. There were no significant differences between healthy and asthmatic subjects regarding IL-35 levels. Polymorphisms in cytokine IL-4, IL-10, tumor necrosis factor (TNF)-α, and IL-2 were susceptible to childhood asthma in the Iranian population. Conclusions: Increased IL-33 and IL-17 levels were related to disease severity in childhood asthma. Four cytokine polymorphisms (IL-4, IL-10, IL-2, and TNF-α) were associated with the risk of pediatric asthma in the Iranian population.

Significant Association of Chitinase 3-like 1 Genotypes to Asthma Risk in Taiwan

Chitinase 3-like 1 (CHI3L1) is overexpressed in asthma, and negatively associated with forced expiratory volume in the first second. This study aimed at evaluating whether CHI3L1 genotypes affect asthma risk. The blood samples of 198 asthma patients and 453 control subjects were collected, and the genotypic patterns of CHI3L1 -131C/G (rs4950928) and -247G/A (rs1262491437) were examined. The percentages of CG and GG at CHI3L1 -131C/G were 32.8% and 7.6% among the asthma cases, respectively, significantly higher than the 23.8% and 3.1% among the non-asthmatic healthy subjects (p for trend=0.0009). The allelic frequency distribution analysis showed that the G allele at CHI3L1 - 131C/G conferred a significantly higher asthma risk than the wild-type C allele (p<0.0001). The genotypic and allelic frequency analyses for CHI3L1 -247G/A did not show any significant difference. The G allele at CHI3L1-131C/G serves as a biomarker in determining personal susceptibility to asthma in Taiwan.

Enhanced mitophagy in bronchial fibroblasts from severe asthmatic patients.

Sub-epithelial fibrosis is a characteristic feature of airway remodeling in asthma which correlates with disease severity. Current asthma medications are ineffective in treating fibrosis. In this study, we aimed to investigate the mitochondrial phenotype in fibroblasts isolated from airway biopsies of non-asthmatic and severe asthmatic subjects by examining mitophagy as a mechanism contributing to fibroblast persistence and thereby, fibrosis in severe asthma. Bioinformatics analysis of publicly available transcriptomic data was performed to identify the top enriched pathways in asthmatic fibroblasts. Endogenous expression of mitophagy markers in severe asthmatic and non-asthmatic fibroblasts was determined using qRT-PCR, western blot and immunofluorescence. Mitophagy flux was examined by using lysosomal protease inhibitors, E64d and pepstatin A. Mitochondrial membrane potential and metabolic activity were also evaluated using JC-1 assay and MTT assay, respectively. Bioinformatics analysis revealed the enrichment of Pink/Parkin-mediated mitophagy in asthmatic fibroblasts compared to healthy controls. In severe asthmatic fibroblasts, the differential expression of mitophagy genes, PINK1 and PRKN, was accompanied by the accumulation of PINK1, Parkin and other mitophagy proteins at baseline. The further accumulation of endogenous LC3BII, p62 and PINK1 in the presence of E64d and pepstatin A in severe asthmatic fibroblasts reinforced their enhanced mitophagy flux. Significantly reduced mitochondrial membrane potential and metabolic activity were also demonstrated at baseline confirming the impairment in mitochondrial function in severe asthmatic fibroblasts. Interestingly, these fibroblasts displayed neither an apoptotic nor senescent phenotype but a pro-fibrotic phenotype with an adaptive survival mechanism triggered by increased AMPKα phosphorylation and mitochondrial biogenesis. Our results demonstrated a role for mitophagy in the pathogenesis of severe asthma where the enhanced turnover of damaged mitochondria may contribute to fibrosis in severe asthma by promoting the persistence and pro-fibrotic phenotype of fibroblasts.

Extended nitric oxide analysis in patients with chronic rhinosinusitis with nasal polyps, with or without associated asthma

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex inflammatory disease highly impacting patient’s quality of life, and associated with lower airway inflammation often evolving into asthma. Exhaled nitric oxide (FENO) is a non-invasive tool to assess Type 2 airway inflammation and its extended analysis allows to differentiate between alveolar concentration (CalvNO) and bronchial output (JawNO). It is also possible to assess the sino-nasal production of nitric oxide (nNO). We studied extended nitric oxide production in patients with CRSwNP with or without associated asthma. Consecutive adult patients with CRSwNP, with or without asthma, and 15 healthy controls were enrolled. Exclusion criteria were: smoking, uncontrolled asthma, recent upper or lower airway infections and oral corticosteroid therapy in the 4 weeks preceding clinical evaluation. Patients’ demographic and clinical data were collected; patients underwent pulmonary function tests and extended nitric oxide analysis including nasal nNO assessment. A total of 125 subjects were enrolled (15 healthy controls; 69 with CRSwNP and asthma, and 41 with CRSwNP only). FENO, JawNO and CalvNO values were higher, while nNO was lower, in all patients with CRSwNP compared to healthy controls; no difference was found in CalvNO between patients with concomitant asthma and non-asthmatic subjects; in asthmatic patients, FENO and JawNO were significantly higher, while nNO values was lower, compared to patients with CRSwNP only. These results suggest that CRSwNP could be the first manifestation of a more complex systemic inflammatory pathology driven by Type 2 inflammation. An ‘inflammatory gradient’ hypothesis could describe a pattern of inflammation in CRSwNP patients that starts distally in the alveoli. Finally, our study indirectly reinforces the concept that novel biological drugs could become valid therapeutic options for nasal polyposis.

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

BackgroundAirway 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.ObjectiveWe 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 MethodsAll 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.ResultsVDR 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.ConclusionDHBFCs 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.

Relationship between opiates and asthma in the determination of death

Several studies have shown an association between asthma and opiate abuse. This retrospective study aims to analyse the demographic, toxicological, and seasonal differences in asthmatic and non-asthmatic subjects who died of opiates. In addition, the relationship between toxicological levels of opiates and histologic grade of lung inflammation is examined.Deaths from 2013 to 2018 involving opiates as the primary cause of death in Cook County, Illinois (USA) were reviewed. Twenty-six cases of opiate deaths of individuals with a history of asthma and lung histology slides available were identified. In comparison, 40 cases of deaths due to opiates only were analysed. A check-list system for the evaluation of the grade of microscopic inflammation in asthma was developed.We found statistically significant differences between the asthmatics and the non-asthmatics regarding demography (age and race) and toxicology (6-MAM presence). In particular, the “opiate and asthma group” was mainly composed of African-American subjects, in contrast with the “opiate group”, consisting mostly of Caucasian. The mean age was significantly higher in the “opiate and asthma group” compared with the “opiate group”. A greater presence of 6-MAM was detected in the “opiate group” compared with the “opiate and asthma group”. While we expected to find that low opiate levels would lead to deaths in asthmatics and, in particular, that lower opiate concentrations would cause deaths in subjects with higher grades of histologic inflammation, our study suggests that the quantity of drug and the level of inflammation are not statistically significant in the determination of death. We, therefore, recommend histologic examination of the lungs to evaluate for asthma, particularly in suspected low-level opiate-related deaths, to help further clarify any relationship between asthma and opiate use.

Lung parenchymal and airway changes on CT imaging following allergen challenge and bronchoalveolar lavage in atopic and asthmatic subjects.

Computed tomography (CT) imaging findings in the lungs in the setting of an acute allergic response and following bronchoalveolar lavage (BAL) are not well established. Our goals are to characterize the pulmonary CT findings of acute allergic response in both asthmatic and non-asthmatic subjects and, secondarily, to characterize the pulmonary imaging findings following BAL. In this prospective observational (cohort) study, we identified atopic, asthmatic (AA) and atopic, non-asthmatic (ANA) subjects. CT of the chest was performed following BAL and instillation of an allergen (AL) and of an inert diluent (DL). Two radiologists analyzed the CT examinations for airway and parenchymal changes. We had a cohort of 20 atopic subjects (AA=10, ANA=10; F=11, M=9; median age: 23.5 years, range: 18-48 years). Compared to diluent instillation and BAL, allergen instillation resulted in more significant bronchial wall thickening (AL=70%, DL=0%, BAL=0%, P<0.01), consolidations (AL=55%, DL=0%, BAL=15%, P<0.05), and septal thickening (AL=35%, DL=0%, BAL=0%, P<0.01). When present, consolidations tended to be more common in asthmatic subjects compared to non-asthmatics following instillation of the allergen, although this did not reach statistical significance (AA=80% vs. ANA=30%; P=0.07). BAL, on the other hand, resulted in more ground-glass opacities (BAL=15/20, 75% vs. AL=2/20, 10%, vs. DL=0/20, 0%; P<0.01). Acute allergic response in the lungs can result in significant bronchial wall thickening, septal thickening, and consolidations in those with atopy, particularly those with asthma. Localized ground-glass opacities may be expected following BAL, and care should be taken so as to not misinterpret these as significant pathology.

IL-17 Induced Autophagy Regulates Mitochondrial Dysfunction and Fibrosis in Severe Asthmatic Bronchial Fibroblasts.

The accumulation of fibroblasts, their synthesis of extracellular matrix (ECM) proteins and their innate resistance to apoptosis are characteristics of subepithelial fibrosis observed in severe asthma. Interleukin-17 (IL-17) is an important regulator of airway remodeling in asthma. However, the contribution of IL-17 to the pro-fibrotic phenotype of bronchial fibroblasts is not well-characterized. In this study, we investigated whether IL-17 induced autophagy regulates mitochondrial and pro-fibrotic function in bronchial fibroblasts. The primary cultured bronchial fibroblasts isolated from non-asthmatic (NHBF) and severe asthmatic (DHBF) subjects were treated with IL-17 in order to ascertain its effect on mitochondrial function, mitochondrial quality control, and apoptosis using immunoblotting and flow cytometric analyses. At baseline, DHBF exhibited higher levels of mitophagy and mitochondrial biogenesis compared to NHBF. Immunohistochemical evaluation of bronchial biopsies showed intense PINK1 immunoreactivity in severe asthma than in control. IL-17 intensified the mitochondrial dysfunction and impaired the mitochondrial quality control machinery in NHBF and DHBF. Moreover, IL-17 augmented a pro-fibrotic and anti-apoptotic response in both group of fibroblasts. Inhibition of autophagy using bafilomycin-A1 reduced PINK1 expression in NHBF and restored the IL-17 mediated changes in PINK1 to their basal levels in DHBF. Bafilomycin-A1 also reversed the IL-17 associated fibrotic response in these fibroblasts, suggesting a role for IL-17 induced autophagy in the induction of fibrosis in bronchial fibroblasts. Taken together, our findings suggest that IL-17 induced autophagy promotes mitochondrial dysfunction and fibrosis in bronchial fibroblasts from both non-asthmatic and severe asthmatic subjects. Our study provides insights into the therapeutic potential of targeting autophagy in ameliorating fibrosis, particularly in severe asthmatic individuals.

Treatment of COVID-19-exacerbated asthma: should systemic corticosteroids be used?

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a new rapidly spreading infectious disease. Current guidance from the World Health Organization (WHO) highlights asthmatics as a high-risk group for severe illness from COVID-19. Viruses are common triggers of asthma exacerbations and the current SARS-CoV-2 pandemic raises several questions regarding the optimum management strategies. Here, we discuss the contentious issue of whether the mainstay therapy systemic corticosteroids should be used in the routine management of COVID-19-associated asthma exacerbations. Recent guidance from the WHO has advised against the use of corticosteroids if COVID-19 is suspected due to concerns that these agents may impair protective innate antiviral immune responses. This may not be appropriate in the unique case of asthma exacerbation, a syndrome associated with augmented type 2 inflammation, a disease feature that is known to directly inhibit antiviral immunity. Corticosteroids, through their suppressive effects on type 2 inflammation, are thus likely to restore impaired antiviral immunity in asthma and, in contrast to non-asthmatic subjects, have beneficial clinical effects in the context of SARS-CoV-2 infection.

Factors that affect blood eosinophil counts in a non-asthmatic population: Post hoc analysis of data from Brazil

BackgroundImproved understanding of the normal range of blood eosinophil counts (BEC) and conditions that influence them in non-asthmatic individuals should allow more accurate estimation of the threshold at which eosinophilic disease should be considered, diagnosed, and treated. This analysis investigated the impact of atopy, smoking, and parasitic infection on BEC. MethodsThis was a post hoc analysis of non-asthmatic subjects from a case-control study (CONEP 450/10) conducted at the Program for Control of Asthma in Bahia (ProAR). Participant BECs were measured at baseline; correlations between predefined risk factors and BEC were assessed via univariate and stratified analysis. ResultsOf the 454 participants included, 3% were helminth parasite-positive, 18% were non-helminth parasite-positive; and 450 had BEC data. The median (interquartile range [IQR]) BEC was 152 (96, 252) cells/μL. Any positive skin prick test, elevated total immunoglobulin E, allergic rhinitis, and being a current smoker were all individually associated with higher BEC (p < 0.05) compared with BEC in participants without these factors, but having a non-helminthic parasitic infection was not. Participants with all 4 risk factors that were associated with higher BEC had a median (IQR) BEC of 192 cells/μL (94, 416) versus 106 cells/μL (70, 164) for those with no risk factors. ConclusionsIn non-asthmatic subjects, atopy, allergic rhinitis, and current smoking status were associated with higher BEC compared with subjects without these factors, but BEC values were well below the threshold commonly accepted as normal. Therefore, BEC should be interpreted in the context of an individual's medical conditions and other BEC-influencing factors.

A thymic stromal lymphopoietin polymorphism may provide protection from asthma by altering gene expression

Genome-wide association studies have identified associations of the single nucleotide polymorphism rs1837253 in the thymic stromal lymphopoietin (TSLP) gene with asthma, allergic disease and eosinophilia. The TSLP gene encodes two isoforms, long and short, and previous studies have indicated functional differences between these two isoforms. We investigated the expression of these TSLP isoforms in response to a pro-inflammatory signal, and the role of the rs1837253 genotype in gene isoform regulation. We cultured nasal epithelial cells of asthmatic and non-asthmatic subjects and evaluated poly(I:C)-induced TSLP protein secretion using multiplex protein assays and gene expression profiles of the TSLP isoforms, and related genes using real-time qPCR. We correlated these profiles with rs1837253 genotype. Asthmatic nasal epithelial cells exhibited increased TSLP protein secretion compared with nasal epithelial cells from healthy controls. The long TSLP isoform was more responsive to poly(I:C) stimulation. Additionally, the minor T allele of rs1837253 was less inducible than the major C allele, suggesting differential regulation; this may explain the "protective" effects of the T allele in asthma. Our results provide important insights into the differential regulation and function of TSLP isoforms, including the role of TSLP rs1837253 polymorphisms in allergic inflammatory processes. The key finding on the influence of TSLP genetic variation on disease expression/endotype could provide basis for investigation into targeted biologics for anti-TSLP therapies.

Chlamydia pneumoniae decreases CD4+ and CD8+ T effector memory IL-2 responses in stimulated peripheral blood mononuclear cells in non-asthmatic subjects

Chlamydia pneumoniae decreases CD4+ and CD8+ T effector memory IL-2 responses in stimulated peripheral blood mononuclear cells in non-asthmatic subjects

Indicators of metabolic syndrome in normotensive normoglycemic asthmatic patients

Pathophysiology of hypertension and bronchial asthma (BA) shares many similarities, especially those related to the metabolic syndrome (MS). In this study, the indicators of the MS were evaluated in normoglycemic normotensive asthmatic patients to clarify if the components of the MS can still interact to increase the risk of BA, provided that blood pressure and glucose level are kept within the normal physiological ranges. Body mass index (BMI), waist circumference (WC), mean arterial blood pressure (MABP), fasting blood glucose (FBG) and fasting blood insulin (FBI) levels, the quantitative insulin sensitivity check index (QUICKI), serum lipid profile, and spirometric measurements were all compared between 120 asthmatic patients and 59 non-asthmatic subjects. Cigarette smoking, pregnancy, age below 20 years or above 40 years, diabetes mellitus and hypertension, and other chronic diseases were excluded from all studied groups. Asthmatic patients demonstrated higher WC (median [25th-75th interquartile]=88.50 [78.00-101.75], FBI [19.98 (11.12-40.14)], and triglyceride (TG) level [109.5 (76.50-134.0)]) compared with non-asthmatic subjects (81.00 [72.00-92.00], 13.78 [8.84-30.24], and 89.00 [64.25-104], P<0.05). QUICKI and MABP were lower in asthmatic patients (0.310 [0.283-0.338] and 86.66 [83.33-93.33]) compared with non-asthmatic subjects (0.320 [0.297-0.353] and 93.33 [83.33-93.33]), (P<0.05). BMI, FBG, low-density lipoprotein, high-density lipoprotein, and total cholesterol levels were comparable in the studied groups. The present finding gives further evidence for higher WC, FBI, TG level, and insulin resistance in normotensive, normoglycemic asthmatic patients compared to healthy controls. The findings of this study suggested that abdominal obesity, hypertriglyceridemia, hyperinsulinemia, and insulin resistance may still be interacting and hence increase the risk of BA in normotensive, normoglycemic subjects.

Significant Association of MMP2 Promoter Genotypes to Asthma Susceptibility in Taiwan

Matrix metalloproteinase 2 (MMP2) is reported to be overexpressed in asthma; however, its genotypic contribution to asthma is not well studied. Therefore, we examined the association of MMP2 genotypes with asthma risk among Taiwanese. One hundred and ninety-eight asthma patients and 453 non-asthmatic subjects were determined with respect to their MMP2 -1306 (rs243845) and -735 (rs2285053) genotypes. CT and TT at MMP2 rs243845 are 17.7% and 1.5% among asthma cases, whereas their presence in healthy subjects is at 28.1% and 2.4%, respectively (p for trend=0.0118). In detail, the CT genotype in MMP2 rs243845 was associated with a decreased asthma risk [adjusted odds ratio (OR)=0.57, 95% confidence interval (CI)=0.37-0.78, p=0.0040], and the T allele conferred a significantly lower asthma risk compared to the wild-type C allele (adjusted OR=0.55, 95%CI=0.43-0.77, p=0.0042). No significance was found for MMP2 rs2285053. The genotype of CT in MMP2 rs243845 may serve as a novel biomarker in determining susceptibility to asthma in Taiwan.

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

BackgroundRecent reports have suggested that lower vitamin D serum levels are associated with susceptibility to and severity of asthma in different white populations, which may be due to a lack of sunlight exposure, genetic polymorphism of vitamin D pathway genes, and dietary intake. We investigated the associations between vitamin D concentration, genetic polymorphism of the vitamin D receptor (VDR), and asthma traits in Mongolian and Taiwanese populations that inhabited two different geographical areas. MethodsIn total, 328 Han Taiwanese subjects and 381 Mongolian subjects were enrolled, and their vitamin D serum levels assayed. Genomic DNA of 178 Han Taiwanese subjects and 90 Mongolian subjects was obtained from blood samples. Single-nucleotide polymorphisms (SNPs) of VDR, ApaI (rs7975232), TaqI (rs731236), BsmI (rs1544410) and FokI (rs2228570), were selected for genotyping. Logistic regression analyses were performed to detect an association between allergic asthma status and the interaction of the VDR SNP and serum vitamin D concentration in the case–control samples. ResultsWe observed a significantly lower vitamin D level in the Mongolian subjects as compared with the Taiwanese population. In particular, in the population under 14 years of age, the serum vitamin D level was significantly higher in the Taiwanese population, in both non-asthmatic and asthmatic subjects, than in the Mongolian non-asthmatic and asthmatic subjects, respectively (P < 0.01). Moreover, the vitamin D level in the asthmatic children was significantly lower than that in the non-asthmatic children in both the Taiwanese and Mongolian populations (P < 0.01, respectively). Furthermore, we found that the rs2228570 genotype (OR, 3.763) of the VDR SNP and the vitamin D concentration (lower than 40 ng/ml, OR: 38.938) both contribute to increased susceptibility to bronchial asthma. ConclusionOur results demonstrated an association between vitamin D concentration and the risk of asthma in two populations of differing ethnicity living in different geographical areas. This information implies a potential role of vitamin D in the prevention and treatment of asthma worldwide.

Indoor bacterial microbiota and development of asthma by 10.5 years of age

Early-life indoor bacterial exposure is associated with the risk of asthma, but the roles of specific bacterial genera are poorly understood. We sought to determine whether individual bacterial genera in indoor microbiota predict the development of asthma. Dust samples from living rooms were collected at 2months of age. The dust microbiota was characterized by using Illumina MiSeq sequencing amplicons of the bacterial 16S ribosomal RNA gene. Children (n=373) were followed up for ever asthma until the age of 10.5years. Richness was inversely associated with asthma after adjustments (P=.03). The phylogenetic microbiota composition in asthmatics patients' homes was characteristically different from that in nonasthmatic subjects' homes (P=.02, weighted UniFrac, adjusted association, permutational multivariate analysis of variance, PERMANOVA-S). The first 2 axis scores of principal coordinate analysis of the weighted UniFrac distance matrix were inversely associated with asthma. Of 658 genera detected in the dust samples, the relative abundances of 41 genera correlated (r>|0.4|) with one of these axes. Lactococcus genus was a risk factor for asthma (adjusted odds ratio, 1.36 [95% CI, 1.13-1.63] per interquartile range change). The abundance of 12 bacterial genera (mostly from the Actinomycetales order) was associated with lower asthma risk (P<.10), although not independently of each other. The sum relative abundance of these 12 intercorrelated genera was significantly protective and explained the majority of the association of richness with less asthma. Our data confirm that phylogenetic differences in the microbiota of infants' homes are associated with subsequent asthma risk and suggest that communities of selected bacteria are more strongly linked to asthma protection than individual bacterial taxa or mere richness.

Multi-Method Molecular Characterisation of Human Dust-Mite-associated Allergic Asthma

Asthma is a chronic inflammatory disorder of the airways. Disease presentation varies greatly in terms of cause, development, severity, and response to medication, and thus the condition has been subdivided into a number of asthma phenotypes. There is still an unmet need for the identification of phenotype-specific markers and accompanying molecular tools that facilitate the classification of asthma phenotype. To this end, we utilised a range of molecular tools to characterise a well-defined group of female adults with poorly controlled atopic asthma associated with house dust mite (HDM) allergy, relative to non-asthmatic control subjects. Circulating messenger RNA (mRNA) and microRNA (miRNA) were sequenced and quantified, and a differential expression analysis of the two RNA populations performed to determine how gene expression and regulation varied in the disease state. Further, a number of circulating proteins (IL-4, 5, 10, 13, 17 A, Eotaxin, GM-CSF, IFNy, MCP-1, TARC, TNFα, Total IgE, and Endotoxin) were quantified to determine whether the protein profiles differed significantly dependent on disease state. Finally, we utilised a previously published assessment of the circulating “blood microbiome” performed using 16S rRNA amplification and sequencing. Asthmatic subjects displayed a range of significant alterations to circulating gene expression and regulation, relative to healthy control subjects, that may influence systemic immune activity. Notably, several circulating mRNAs were detected in just the asthma group or just in the control group, and many more were observed to be expressed at significantly different levels in the asthma group compared to the control group. Proteomic analysis revealed increased levels of inflammatory proteins within the serum, and decreased levels of the bacterial endotoxin protein in the asthmatic state. Comparison of blood microbiome composition revealed a significant increase in the Firmicutes phylum with asthma that was associated with a concomitant reduction in the Proteobacteria phylum. This study provides a valuable insight into the systemic changes evident in the HDM-associated asthma, identifies a range of molecules that are present in the circulation in a condition-specific manner (with clear biomarker potential), and highlights a range of hypotheses for further study.

Asthma as an outcome: Exploring multiple definitions of asthma across birth cohorts in the Environmental influences on Child Health Outcomes Children's Respiratory and Environmental Workgroup

Asthma definitions vary widely across research studies and feature a trade-off between inclusivity and precision. Harmonizing definitions across multiple asthma birth cohort studies highlights these challenges.