Nonasthmatic Subjects Research Articles

Th2 and IL-17 responses inChlamydia pneumoniae-stimulated PBMC in asthmatic and non-asthmatic subjects

Abstract Background Chlamydia pneumoniae (C. pneumoniae) is a gram-negative intracellular bacterium that causes respiratory infections in humans, including asthmatic and non-asthmatic subjects. C. pneumoniae activates cells in vitro and produces cytokines that may contribute to the inflammatory responses observed in asthma. Different asthma endotypes are described, including Th2-high and Th2-low. Th2-low endotypes are characterized by IL-17 production and neutrophilic inflammation. The aim of this study was to investigate the role of C. pneumoniae in regulating Th2 versus Th17 responses in peripheral blood mononuclear (PBMC) from subjects with or without asthma. Methods PBM) (1×106/mL) from asthmatic (N=6) and non-asthmatic subjects (N=14) were infected +/- C. pneumoniae TW-183 at a multiplicity of infection (MOI) = 0.1, using dose responses (1:10, 1:100), and cultured 48 hrs. Cytokine responses (Interferon (IFN)-gamma, Interleukin (IL)-2, IL-4, IL-17 A/F) were measured in supernatants (ELISA). Results Comparison of cytokine responses (the mean differences in non-asthmatic versus asthmatic subjects) were significant for IFN gamma (unstimulated; P<0.0001), IL-2 (unstimulated and 1:100; P<0.0001, P=0.0002, respectively), IL-4 (unstimulated, 1:10, 1:100; P=0.0001, P<0.0001, P<0.0001, respectively) and IL-17 A/F (unstimulated, P<0.0001) (Wilcoxon signed-rank test). Cytokine levels were higher in asthmatic subjects for IFN-gamma (unstimulated,1:10, 1:100), IL-2 (unstimulated), and IL-17 A/F (unstimulated) compared with non-asthmatic subjects. However, IL-4 levels were higher in non-asthmatics (unstimulated, 1:10, 1:100). Conclusion Differences in Th2 and IL-17 cytokines responses in PBMC from subjects with and without asthma may indicate the involvement of cell-mediated immunity, while Th17 responses, which were increased in subjects with asthma at baseline, did not increase further in response to C. pneumoniae stimulation.

Automated asthma detection in a 1326-subject cohort using a one-dimensional attractive-and-repulsive center-symmetric local binary pattern technique with cough sounds

Asthma is a common disease. The clinical diagnosis is usually confirmed on a pulmonary function test, which is not always readily accessible. We aimed to develop a computationally lightweight handcrafted machine learning model for asthma detection based on cough sounds recorded using mobile phones. Toward this aim, we proposed a novel feature extractor based on a one-dimensional version of the published attractive-and-repulsive center-symmetric local binary pattern (1D-ARCSLBP), which we tested on a new cough sound dataset. We prospectively recorded cough sounds from 511 asthmatics and 815 non-asthmatic subjects (comprising mostly healthy volunteers), which yielded 1875 one-second cough sound segments for analysis. Our model comprised four steps: (i) preprocessing, in which speech signals and stop times (silent zones between coughs) were removed, leaving behind analyzable cough sound segments; (ii) feature extraction, in which tunable q-factor wavelet transformation was used to perform multilevel signal decomposition into wavelet subbands, allowing 1D-ARCSLBP to extract local low- and high-level features; (iii) feature selection, in which neighborhood component analysis was used to select the most discriminative features; and (iv) classification, in which a standard shallow cubic support vector machine was deployed to calculate binary classification results (asthma versus non-asthma) using tenfold and leave-one-subject-out cross-validations. Our model attained 98.24% and 96.91% accuracy rates with tenfold and leave-one-subject-out cross-validation strategies, respectively, and obtained a low-time complexity. The excellent results confirmed the feature extraction capability of 1D-ARCSLBP and the feasibility of the model being developed into a real-world application for asthma screening.

Interplay of interleukins (IL6, IL10) and 25 hydroxycholecalciferol in asthmatic subjects with chronic post-COVID condition (PCC).

The study aimed to compare and correlate serum levels of IL-6, 10, and 25-hydroxycholecalciferol in individuals with asthma with and without post-COVID condition (PCC). The study was designed to investigate the inflammatory response and serum 25-hydroxycholecalciferol status in asthmatics with and without PCC. A cross-sectional study of 252 subjects (128 asthmatics and 124 non-asthmatic subjects) was carried out. Interleukins and 25-hydroxycholecalciferol levels were estimated on ELISA. The principle findings were that IL-6 and 25-hydroxycholecalciferol levels were significantly increased (p<0.001), while IL-10 levels were non-significant in asthmatics with PCC compared to those without PCC. However, 25-hydroxycholecalciferol levels were significantly increased, but no significant change was observed in IL-6, and IL-10 levels in non-asthmatics with and without chronic PCC. A significant positive correlation (r = 0.258) was found between 25-hydroxycholecalciferol and IL-6 but a significant negative correlation (r = -0.227) with IL-10 in asthmatics with PCC. Similarly, a significant negative correlation (r = -0.285) was found between 25-hydroxycholecalciferol and IL-10 but was non-significant with IL-6 in asthmatics without PCC. The correlation of 25-hydroxycholecalciferol with IL-10 was significant (0.683), but IL-6 was non-significant in non-asthmatics with PCC. Multiple regression analysis showed that age, IL-6, gender, and PCC were significantly related in adjusted values to 25-hydroxycholecalciferol. This study sheds light on the complex liaison between 25-hydroxycholecalciferol levels and inflammatory responses in asthmatics, especially those with PCC. The findings suggest that although asthmatics with PCC maintain sufficient levels of 25-hydroxycholecalciferol, they show a substantial increase in the proinflammatory response. This suggests that PCC exacerbates the pro-inflammatory response in asthma. Moreover, the study reveals that asthmatics, whether with or without PCC, display a negative correlation between 25-hydroxycholecalciferol and the anti-inflammatory response. This emphasizes the main influence of asthma on the overall inflammatory response. These findings reveal a complex interplay between vitamin D levels and inflammatory mediators in asthmatic individuals with and without PCC.

Cytokine responses in Chlamydia pneumoniae-stimulated PBMC in asthmatic and non-asthmatic subjects.

Cytokine responses in Chlamydia pneumoniae-stimulated PBMC in asthmatic and non-asthmatic subjects.

Asthmatic patients with high serum amyloid A have proinflammatory HDL: Implications for augmented systemic and airway inflammation

RationaleSerum amyloid A (SAA) is bound to high-density lipoproteins (HDL) in blood. Although SAA is increased in the blood of asthmatics, it is not known whether this modifies asthma severity. ObjectiveTo define the clinical characteristics of asthmatics with high SAA levels and assess whether HDL from SAA-high asthmatics is pro-inflammatory. MethodsSAA levels in serum from asthmatic and non-asthmatic subjects were quantified by ELISA. HDL isolated from asthmatics with high SAA levels were used to stimulate human monocytes and were intravenously administered to BALB/c mice. ResultsA SAA level > 108.8 μg/ml was defined as the threshold to identify 11% of an asthmatic cohort (n = 146) as being SAA-high. SAA-high asthmatics were characterized by increased serum C-reactive protein, IL-6, and TNF-α; older age; and an increased prevalence of obesity and severe asthma. HDL isolated from SAA-high asthmatics (SAA-high HDL) had an increased content of SAA as compared to HDL from SAA-low asthmatics and induced the secretion of IL-6, IL-1β and TNF-α from human monocytes via a FPR2/ATP/P2X7R axis. Intravenous administration to mice of SAA-high HDL, but not normal HDL, induced systemic inflammation and amplified allergen-induced neutrophilic airway inflammation and goblet cell metaplasia. ConclusionSAA-high asthmatics are characterized by systemic inflammation, older age, and an increased prevalence of obesity and severe asthma. HDL from SAA-high asthmatics is pro-inflammatory and, when intravenously administered to mice, induces systemic inflammation, and amplifies allergen-induced neutrophilic airway inflammation. This suggests that systemic inflammation induced by SAA-high HDL may augment disease severity in asthma.

Discrepancy in the suppressive function of regulatory T cells in allergic asthmatic vs. allergic rhinitis subjects upon low-dose allergen challenges.

Regulatory T cells (Tregs) contribute to the maintenance of immunological tolerance. There is evidence of impaired function of these cells in people with asthma and allergy. In this study, we evaluated and compared the function of Tregs in allergic asthmatic and allergic non-asthmatic patients, both before and after low-dose allergen challenges. Three groups of subjects were recruited for a baseline evaluation: healthy controls without allergy or asthma, allergic asthmatic subjects, and allergic non-asthmatic subjects. All of them were subjected to expiratory flow measurements, sputum induction, and blood sampling. In addition, both groups of allergic subjects underwent low-dose allergen challenges. Tregs were isolated from whole blood using CD4+CD25high and CD127low staining. The suppression function was measured by flow cytometry. The levels of IL-10, IFN-γ, IgG4, IgA, and TGF-β were measured using ELISA, and sputum Foxp3 was evaluated using qRT-PCR. The suppressive function of Tregs in healthy controls was significantly higher than in allergic asthmatic or allergic non-asthmatic subjects. Repeated exposure to low doses of allergen increased the suppressor function of Tregs in allergic non-asthmatic subjects but decreased it in allergic asthmatic subjects. Foxp3 gene expression was increased in induced sputum in allergic non-asthmatic subjects, whereas it did not change in asthmatic subjects. Serum IL-10 level was decreased in allergic asthmatic subjects after allergen challenge but not in allergic non-asthmatic subjects. IFN-γ level increased upon allergen challenge in allergic non-asthmatic subjects. IgG4 level was higher in allergic non-asthmatic subjects than in allergic asthmatic subjects. Low-dose allergen challenges stimulate the suppressor function of Tregs in non-asthmatic allergic subjects but not in allergic asthmatic subjects.

Effect of Obesity on the Expression of Genes Associated with Severe Asthma-A Pilot Study.

Asthma is a complex condition resulting from the interaction of genes and environment. Obesity is a risk factor to develop asthma and contributes to poor response to asthma therapy and severity. The aim of the study was to evaluate the effect of obesity on the expression levels of genes previously associated with severe asthma. Three groups of subjects were studied: non-obese asthmatics (NOA), obese asthma patients (OA), and non-asthmatic obese subjects (O). Previously reported overexpressed (IL-10, MSR1, PHLDA1, SERPINB2, and CD86) and underexpressed genes (CHI3L1, CPA3, IL-8, and PI3) in severe asthma were analyzed by RT-qPCR in peripheral blood mononuclear cells (PBMCs). In the overexpressed genes, obesity significantly decreased the expression of MSR1 and PHLDA1 and had no effects on CD86, IL-10, and SERPINB2. In underexpressed genes, obesity did not affect PI3, CHI3L1, and IL-8 and significantly reduced CPA3 expression. The results of this study show that obesity should be included among the known factors that can contribute toward modifying the expression of genes associated with asthma and, in particular, severe asthma.

Plasma sterols and vitamin D are correlates and predictors of ozone-induced inflammation in the lung: A pilot study.

Ozone (O3) exposure causes respiratory effects including lung function decrements, increased lung permeability, and airway inflammation. Additionally, baseline metabolic state can predispose individuals to adverse health effects from O3. For this reason, we conducted an exploratory study to examine the effect of O3 exposure on derivatives of cholesterol biosynthesis: sterols, oxysterols, and secosteroid (25-hydroxyvitamin D) not only in the lung, but also in circulation. We obtained plasma and induced sputum samples from non-asthmatic (n = 12) and asthmatic (n = 12) adult volunteers 6 hours following exposure to 0.4ppm O3 for 2 hours. We quantified the concentrations of 24 cholesterol precursors and derivatives by UPLC-MS and 30 cytokines by ELISA. We use computational analyses including machine learning to determine whether baseline plasma sterols are predictive of O3 responsiveness. We observed an overall decrease in the concentration of cholesterol precursors and derivatives (e.g. 27-hydroxycholesterol) and an increase in concentration of autooxidation products (e.g. secosterol-B) in sputum samples. In plasma, we saw a significant increase in the concentration of secosterol-B after O3 exposure. Machine learning algorithms showed that plasma cholesterol was a top predictor of O3 responder status based on decrease in FEV1 (>5%). Further, 25-hydroxyvitamin D was positively associated with lung function in non-asthmatic subjects and with sputum uteroglobin, whereas it was inversely associated with sputum myeloperoxidase and neutrophil counts. This study highlights alterations in sterol metabolites in the airway and circulation as potential contributors to systemic health outcomes and predictors of pulmonary and inflammatory responsiveness following O3 exposure.

CD4+ and CD8+ T effector memory responses in Chlamydia pneumoniae-stimulated PBMC in non-asthmatic subjects

Chlamydia pneumoniae (C. pneumoniae) is a gram-negative intracellular bacterium that causes respiratory infection. C. pneumoniae infection can trigger asthma symptoms, but may be underdiagnosed. Immunological differences exist between subjects with or without asthma, with regard to host responses to C. pneumoniae. The heterogeneity of asthma can be better understood by analyzing the repertoire of T-cell subpopulations. The aim of this study was to expand existing knowledge of T effector memory (TEM) lymphocytes through identification of C.

Effect of exercise-induced bronchoconstriction on the configuration of the maximal expiratory flow-volume curve in adults with asthma.

We determined the effect of exercise-induced bronchoconstriction (EIB) on the shape of the maximal expiratory flow-volume (MEFV) curve in asthmatic adults. The slope-ratio index (SR) was used to quantitate the shape of the MEFV curve. We hypothesized that EIB would be accompanied by increases in SR and thus increased curvilinearity of the MEFV curve. Adult asthmatic ( n = 10) and non-asthmatic control subjects ( n = 9) cycled for 6-8 min at 85% of peak power. Following exercise, subjects remained on the ergometer and performed a maximal forced exhalation every 2 min for a total 20 min. In each MEFV curve, the slope-ratio index (SR) was calculated in 1% volume increments beginning at peak expiratory flow (PEF) and ending at 20% of forced vital capacity (FVC). Baseline spirometry was lower in asthmatics compared to control subjects (FEV1 % predicted, 89.1± 14.3 vs. 96.5± 12.2% [SD] in asthma vs. control; p < 0.05). In asthmatic subjects, post-exercise FEV1 decreased by 29.9± 13.2% from baseline (3.48 ± 0.74 and 2.24 ± 0.59 [SD] L for baseline and post-exercise nadir; p < 0.001). At baseline and at all timepoints after exercise, average SR between 80 and 20% of FVC was larger in asthmatic than control subjects (1.48 ± 0.02 vs. 1.23 ± 0.02 [SD] for asthma vs. control; p < 0.005). This averaged SR did not change after exercise in either subject group. In contrast, post-exercise SR between PEF and 75% of FVC was increased from baseline in subjects with asthma, suggesting that airway caliber heterogeneity increases with EIB. These findings suggest that the SR-index might provide useful information on the physiology of acute airway narrowing that complements traditional spirometric measures.

Asthmatic lung fibroblasts promote type 2 immune responses via endoplasmic reticulum stress response dependent thymic stromal lymphopoietin secretion.

Lung fibroblasts contribute to asthma pathology partly through modulation of the immune environment in the airway. Tumor necrosis factor-α (TNFα) expression is upregulated in asthmatic lungs. How asthmatic lung fibroblasts respond to TNFα stimulation and subsequently regulate immune responses is not well understood. Endoplasmic reticulum (ER) stress and unfolded protein responses (UPR) play important roles in asthma, but their functional roles are still under investigation. In this study, we investigated TNFα-induced cytokine production in primary lung fibroblasts from asthmatic vs. non-asthmatic human subjects, and downstream effects on type 2 immune responses. TNFα significantly upregulated IL-6, IL-8, C-C motif chemokine ligand 5 (CCL5), and thymic stromal lymphopoietin (TSLP) mRNA expression and protein secretion by lung fibroblasts. Asthmatic lung fibroblasts secreted higher levels of TSLP which promoted IL-33-induced IL-5 and IL-13 production by peripheral blood mononuclear cells. TNFα exposure enhanced expression of ER stress/UPR pathways in both asthmatic and non-asthmatic lung fibroblasts, especially inositol-requiring protein 1α in asthmatics. ER stress/UPR inhibitors decreased IL-6, CCL5, and TSLP protein secretion by asthmatic lung fibroblasts. Our data suggest that TNFα and lung fibroblasts form an important axis in asthmatic lungs to promote asthmatic inflammation that can be attenuated by inhibiting ER stress/UPR pathway.

Significance of total and specific IgE in asthma of Iraqi adult patients

A case-control retrospective study was conducted during January – June 2019 on 104 patients with asthma (50 females and 54 males) and 111 non-asthmatic healthy subjects matched patients for gender (54 females and 57 males) to assess role of total and specific IgE serum levels in patho-physiology of disease using ELISA and multiplex immunoblot kits. The mean age ± standard deviation of asthma patients was 37.9 ± 12.1 years, while it was lower among control (35.9 ± 10.5 years), but the difference was not significant. Males and females were similarly distributed among asthma cases (48.1 and 51.9%, respectively) and control (48.6 and 51.4%, respectively). Most of asthma cases were observed to have mild disease (49%), followed by moderate and severe asthma (93.4 and 11.5%, respectively). It was also observed that 51.9% of patients had a family history of asthma. With respect to allergen type, 21.2% of asthma cases were seropositive for mixed types of allergens. Median level of total IgE was significantly (p &lt; 0.001(elevated in sera of asthma cases (204.1 ng/ml) compared to control subjects (163.3 ng/ml). The level positively paralleled the severity of disease. The highest level was observed in severe cases (244.9ng/ml, while the lowest level was recorded in mild cases (189.7 ng/ml). The level of specific IgE showed some variations among asthma cases distributed according to the type of allergen, the highest median was recorded in seronegative cases (215.2 ng/ml), while a lowest level was observed in cases seropositive for animal dander (189.3 ng/ml). Logistic regression analysis revealed that total asthma patients, as well as male and female cases were at an increased risk to develop asthma episodes due to elevated serum level of IgE.ROC analysis demonstrated that elevated serum level of IgE occupied a significant (p = 0.001) area under curve (AUC), which was 0.828. In conclusion, the present study confirms the significant role of total and specific IgE in patho-physiology of bronchial asthma and its correlation with disease severity and allergen type in adults

CD4+ T effector memory cell responses in Chlamydia pneumoniae-stimulated peripheral blood mononuclear cells in nonasthmatic subjects.

Chlamydia pneumoniae (C. pneumoniae) is a gram‐negative intracellular bacterium that causes respiratory infection in humans, including subjects with or without asthma. C. pneumoniae activates cells (e.g., monocytes/macrophages) in vitro, and produces cytokines that may contribute to inflammatory responses observed in asthma. Immunological differences exist between subjects with or without asthma, with regard to host responses to C. pneumoniae. The heterogeneity and subsequent diverse pathophysiology of asthma can be better understood by analyzing the repertoire of T‐cell subpopulations; the most common distinction between different asthma endotypes includes cytokines produced by CD4+ cells (T helper (Th)2 high vs. Th2 low).

Status of TNF-α and IL-6 as pro-inflammatory cytokines in exhaled breath condensate of late adolescents with asthma and healthy in the dust storm and non-dust storm conditions.

Exposure to airborne particulate matter (PM) can be considered as an important risk factor for human health. Some cytokines have been recognized as the biomarkers of exposure to air pollution. Experimental studies indicate that PM exposure could be associated with inflammation. Thus, the purpose of this study was to evaluate whether the exposure to air PM is associated with biomarkers of inflammation. The specific aim of this study was to determine the correlation between airborne PM levels and IL-6 and TNF-α as airway inflammation biomarkers among two groups of late adolescents in northwest of Iran. This study included 46 subjects, comprising 23 asthmatic subjects and 23 non-asthmatic persons. Environmental PM (PM10, PM2.5 and PM1) levels were measured in dust storm and non-dust storm days during both cold and warm seasons. Following the sampling of PM, Two pro-inflammatory cytokines of IL-6 and TNF-α in exhaled breath condensate (EBC) were also determined in the EBC samples via commercial ELISA kits. Daily mean ambient air PM10, PM2.5 and PM1 concentrations during the dust storm days was 221.79, 93.13 and 25.52 μg m-3 and in non-dusty days 48.37, 18.54 and 6.1 μg m-3, respectively. Biomarkers levels were significantly (p < 0.001) higher in asthmatic students compared to the non-asthmatic subjects. EBC cytokines levels were increased in dust storm days compared to the non-dusty days (p < 0.001) and were positively correlated with different size of ambient PM concentration. Dust storm conditions can increase the pro-inflammatory cytokines and cause adverse effects on pulmonary health and lung tissue damage.

Variations in the respiratory microbiota amongst asthmatic and non-asthmatic subjects in Jordan

In this work, variation in microbiota in the lower respiratory tract (LRT) among asthmatic and non-asthmatic subjects is identified. All participants (27 asthmatic patients and 27 non-asthmatic subjects) were asked to expectorate a sputum sample in special sterile tubes after rinsing the mouth with a sterilizing solution. The expectorated sputum specimen was immediately homogenized and stored in the deep freezer for DNA extraction for microbial gene sequencing and sequence analyses. For sequencing the V4 region of the 16S rRNA gene was sequenced using Illumina MiSeq, followed by an analysis of alpha and beta diversity. It was found that asthmatic patients had greater bacterial diversity than non-asthmatic subjects. Bacteria associated to the phyla (Bacteroidetes, Proteobacteria, and Firmicutes) accounted for 90 % of all sequences. The relative abundance of Proteobacteria in the asthmatic patients was higher than that of non-asthmatic (30 % vs 17 %; P-value = 0.044), along with a high abundance of the pathogen Haemophilus influenza. In contrast, Firmicutes (41 %) and Bacteroidetes (31 %) showed higher relative abundances in the non-asthmatic subjects. No significant link was found between the type of asthma drug or the method of drug usage (orally or via inhalation) and the respiratory microbiota. Therefore, the variations in LRS microbiota are not caused by the drugs taken by the asthmatic patients, rather they might be connected to the etiology of asthma. Since the asthmatic patients had higher proportions of Haemophilus influenzae, these organisms could be a causative factor in the pathophysiology of asthma.

Decreased expression of airway epithelial Axl is associated with eosinophilic inflammation in severe asthma

BackgroundAirway epithelium-derived cytokines are critical to provoke and perpetuate type 2 inflammation in asthma. Yet it is poorly understood how this epithelial cell-driven inflammatory response is negatively regulated. We previously reported that Axl receptor tyrosine kinase was expressed by basal cells in the airway epithelium and had a role in defining their stem cell identity. However, whether and how Axl regulates airway type 2 inflammation remains unknown. MethodsWe performed immunofluorescence staining to compare Axl expression in airway epithelium between non-asthmatic subjects, mild-moderate asthma and severe asthma. We confirmed this result by interrogating public databases of global gene expression in endobronchial biopsies. We then quantified eosinophil numbers infiltrating into the trachea of wild-type or Axl-knockout mice that were intranasally treated with house dust mite extracts (HDM). Cell-based assays using siRNA targeting Axl were further performed to identify molecules involved in Axl-mediated regulation of inflammation. ResultsHistological assessments and transcriptome analyses revealed decreases in protein and mRNA of Axl in airway basal cells of severe asthmatics. This reduction of Axl expression was correlated with infiltration of eosinophils and mast cells in severe asthmatics. Eosinophil infiltration was more evident in the trachea of Axl-knockout mice in response to repetitive HDM administration. siRNA-mediated knockdown of Axl increased mRNA and protein expression of granulocyte macrophage-colony stimulating factor (GM-CSF) in human bronchial epithelial cells. ConclusionsAxl kinase expressed by basal cells may suppress excessive eosinophilic inflammation via inhibition of GM-CSF in the airway. Axl reduction has clinical implications for the pathogenesis of severe asthma.

Comparison of circulating fibrocytes from non-asthmatic patients with seasonal allergic rhinitis between in and out of pollen season samples

BackgroundAllergic rhinitis is a risk factor for asthma development. In asthma, fibroblast progenitors, fibrocytes, are increased in the blood and bronchial mucosa following allergen exposure. These cells may play a role in lower airways remodeling as observed in non-asthmatic subjects with allergic rhinitis.ObjectiveTo determine the influence of seasonal allergen exposure on blood circulating fibrocytes in allergic rhinitic subjects without asthma.MethodsNon-asthmatic subjects with seasonal allergic rhinitis had blood sampling at baseline and at the peak of rhinitis symptoms. Cells were stained for fibrocyte markers (CD34, CD45, CXCR4, collagen I) and analyzed by flow cytometry.ResultsData from 26 subjects (11M:15F) aged 29 ± 8 years were analysed. Compared to baseline, there was a significant decrease in blood fibrocytes during the pollen season in subjects sensitized to trees [median (25–75 percentile), 9.3 (6.4–20.7)% vs 7.0 (4.2–10.1)%, P = 0.007] and a significant increase in subjects sensitized to grass [12.7 (9.9–23.1)% vs 64.0 (57.6–73.6)%, P < 0.001] and ragweed [8.0 (7.4–10.8)% vs 48.2 (43.5–52.6)%, P < 0.001]. A significant decrease in CXCR4 mean fluorescence was also observed between the two visits [1814 (1261–2235) vs 1352 (814–1796) (arbitrary units), P = 0.02].Conclusions and clinical relevanceThese results contribute to document dynamic variations in blood fibrocytes’ activation and migration into the airways following natural exposure to allergens. These findings may help identify one of the potential factors involved in the development of asthma in allergic rhinitic subjects.

Human Rhinovirus induces specific bronchial smooth muscle cell migration toward bronchial epithelium in severe asthma through the CXCL10/CXCR3-A axis

Severe asthmatic patients are characterized by an increase in both exacerbation frequency and bronchial smooth muscle (BSM) mass. Rhinovirus (RV) infection of the bronchial epithelium (BE) is the main trigger of asthma exacerbations. A decreased distance between BE and BSM mass is associated with the severity of asthma. We hypothesized that RV infection of the BE increased the migration of asthmatic BSM cells, specifically. Serums, biopsies or BSM cells were obtained from 86 severe asthmatic patients and 31 non-asthmatic subjects. BE cells from non-asthmatic subjects were cultured in air-liquid interface and exposed to RV-16. Migration of BSM cells was assessed in response to BE supernatant using chemotaxis assays and live microscopy. Chemokines concentrations were analyzed by transcriptomic and ELISA. Immunocytochemistry, western blot and flow cytometry were used to quantify CXCR3 isoforms distribution. CXCR3 downstream signaling pathways were assessed by calcium imaging and western blot. BSM cells from severe asthmatic patients harbor a specific migration toward RV-infected BE whereas those from non-asthmatic subjects do not. This specific migration is driven by BE CXCL10 production that is increased both in vitro in response to RV infection and in vivo in serum from exacerbating severe asthmatic patients. The mechanism is related to both decreased expression and activation of CXCR3-B specific isoform in BSM cells from severe asthmatic patients. We demonstrate a new mechanism of BSM remodeling in severe asthmatic patients following RV exacerbation. This study highlights the CXCL10/CXCR3-B axis as a new potential therapeutic target in severe asthma.

Computational modeling of nasal nitric oxide flux from the paranasal sinuses: Validation against human experiment.

Nitric oxide (NO) is important in respiratory physiology and airway defense. Although the paranasal sinuses are the major source of nasal NO, transport dynamics between the sinuses and nasal cavities are poorly understood. Exhaled nasal NO tracings were measured in two non-asthmatic subjects (one with allergic rhinitis, one without) using NO analyzer connected via face mask. We subsequently performed computational fluid dynamics NO emission simulations based on individual CT scans and compared to the experimental data. Simulated exhaled NO tracings match well with experimental data (r>0.84, p<0.01) for both subjects, with measured peaks reaching 319.6ppb in one subject (allergic-rhinitis), and 196.9ppb in the other. The CFD simulation accurately captured the peak differences, even though the initial sinus NO concentration for both cases was set to the same 9000ppb based on literature value. Further, the CFD simulation suggests that ethmoid sinuses contributed the most (>67%, other sinuses combined <33%) to total nasal NO emission in both cases and that diffusion contributes more than convective transport. By turning off diffusion (setting NO diffusivity to ~0), the NO emission peaks for both cases were reduced by >70%. Historically, nasal NO emissions were thought to be contributed mostly by the maxillary sinuses (the largest sinuses) and active air movement (convection). Here, we showed that the ethmoid sinuses and diffusive transport dominate the process. These findings may have a substantial impact on our view of nasal NO emission mechanisms and sinus physiopathology in general.

Bronchodilator response and lung function decline: Associations with exhaled nitric oxide with regard to sex and smoking status

BackgroundFractional exhaled nitric oxide (FeNO) is a marker of type-2 inflammation used both to support diagnosis of asthma and follow up asthma patients. The associations of FeNO with lung function decline and bronchodilator (BD) response have been studied only scarcely in large populations. ObjectivesTo study the association between FeNO and a) retrospective lung function decline over 20 years, and b) lung function response to BD among asthmatic subjects compared with non-asthmatic subjects and with regards to current smoking and sex. MethodsLongitudinal analyses of previous lung function decline and FeNO level at follow-up and cross-sectional analyses of BD response and FeNO levels in 4257 participants (651 asthmatics) from the European Community Respiratory Health Survey. ResultsAmong asthmatic subjects, higher percentage declines of FEV1 and FEV1/FVC were associated with higher FeNO levels (p = 0.001 for both) at follow-up. These correlations were found mainly among non-smoking individuals (p = 0.001) and females (p = 0.001) in stratified analyses.Percentage increase in FEV1 after BD was positively associated with FeNO levels in non-asthmatic subjects. Further, after stratified for sex and smoking separately, a positive association was seen between FEV1 and FeNO levels in non-smokers and women, regardless of asthma status. ConclusionsWe found a relationship between elevated FeNO and larger FEV1 decline over 20 years among subjects with asthma who were non-smokers or women. The association between elevated FeNO levels and larger BD response was found in both non-asthmatic and asthmatic subjects, mainly in women and non-smoking subjects.