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Nature Immunology Nov 2019Low exposure to microbial products, respiratory viral infections and air pollution are major risk factors for allergic asthma, yet the mechanistic links between such...
Low exposure to microbial products, respiratory viral infections and air pollution are major risk factors for allergic asthma, yet the mechanistic links between such conditions and host susceptibility to type 2 allergic disorders remain unclear. Through the use of single-cell RNA sequencing, we characterized lung neutrophils in mice exposed to a pro-allergic low dose of lipopolysaccharide (LPS) or a protective high dose of LPS before exposure to house dust mites. Unlike exposure to a high dose of LPS, exposure to a low dose of LPS instructed recruited neutrophils to upregulate their expression of the chemokine receptor CXCR4 and to release neutrophil extracellular traps. Low-dose LPS-induced neutrophils and neutrophil extracellular traps potentiated the uptake of house dust mites by CD11bLy-6C dendritic cells and type 2 allergic airway inflammation in response to house dust mites. Neutrophil extracellular traps derived from CXCR4 neutrophils were also needed to mediate allergic asthma triggered by infection with influenza virus or exposure to ozone. Our study indicates that apparently unrelated environmental risk factors can shape recruited lung neutrophils to promote the initiation of allergic asthma.
Topics: Air Pollutants; Allergens; Animals; Asthma; Dendritic Cells; Disease Models, Animal; Environmental Exposure; Extracellular Traps; Female; Humans; Lipopolysaccharides; Lung; Mice; Neutrophils; Orthomyxoviridae; Ozone; Pyroglyphidae; Receptors, CXCR4; Up-Regulation
PubMed: 31591573
DOI: 10.1038/s41590-019-0496-9 -
Frontiers in Medicine 2022Air trapping is a predictive index for a decline in lung function and mortality in patients with chronic obstructive pulmonary disease (COPD). However, the role of air...
BACKGROUND AND AIMS
Air trapping is a predictive index for a decline in lung function and mortality in patients with chronic obstructive pulmonary disease (COPD). However, the role of air trapping in COPD exacerbation has rarely been studied. Therefore, this study aimed to investigate the impact of air trapping as a continuous parameter on COPD exacerbation.
MATERIALS AND METHODS
To evaluate air trapping, we identified the ratio of residual volume (RV) to total lung capacity (TLC) of patients with COPD from the Korean COPD Subgroup Study (KOCOSS) cohort, which is a multicenter-based, prospective, consecutive cohort in Korea. The primary outcome was a development of COPD exacerbation during 3 years of follow-up.
RESULTS
Of 2,181 participants, 902 patients measured the RV/TLC ratio in the baseline enrollment, and 410 were evaluated for assessing the development of COPD exacerbation. Of 410 patients, the rate of moderate to severe exacerbation and severe exacerbation was 70.7% and 25.9%. A 10% increase of RV/TLC ratio increased the risk of the moderate to severe exacerbation by 35% and severe exacerbation by 36%. In subgroup analysis, an interaction effect between triple inhaled therapy and the RV/TLC ratio for severe exacerbation nullified the association between the RV/TLC ratio and severe exacerbation ( for interaction = 0.002).
CONCLUSIONS
In this prospective cohort study, we found that air trapping (representing RV/TLC ratio as a continuous parameter) showed an association with an increased risk of COPD exacerbation, particularly in patients who have not undergone triple inhaler therapy.
PubMed: 35372402
DOI: 10.3389/fmed.2022.835069 -
American Journal of Respiratory and... Mar 2020
Topics: Aspergillosis; Child; Cystic Fibrosis; Disease Progression; Humans
PubMed: 31904998
DOI: 10.1164/rccm.201912-2309ED -
Journal of the Belgian Society of... 2023Air trapping is a useful sign for early detection of worsening lobar collapse in the follow-up of obstructive atelectasis.
Air trapping is a useful sign for early detection of worsening lobar collapse in the follow-up of obstructive atelectasis.
PubMed: 36721643
DOI: 10.5334/jbsr.3022 -
Journal of Applied Physiology... May 2019Air trapping due to airway closure has been associated with unstable asthma. In addition to airway closure that occurs at lower lung volumes during slow expiration,...
Air trapping due to airway closure has been associated with unstable asthma. In addition to airway closure that occurs at lower lung volumes during slow expiration, there may be further closure during a forced expiration because of airway compression. The purpose of this study was to define a reference range from a nonasthmatic population and investigate the characteristics of compressive air trapping in asthma. Spirometry and plethysmography were performed in 117 nonasthmatic subjects (ages 18-87 yr) and 153 asthma subjects (ages 12-72 yr). Air trapping was assessed as residual lung volume and the ratio of forced expiratory vital capacity (FVC) to slow inspiratory vital capacity (iVC) (FVC/iVC). There were no significant age or sex effects on the FVC/iVC ratio in the nonasthmatic subjects, and a fifth percentile lower limit of normal (LLN) of 0.93 was computed. An FVC/iVC ratio less than LLN defined compressive air trapping. Asthma subjects exhibited an age-related decline in the FVC/iVC ratio of 0.0027 per year ( < 0.0001) in a mixed effects model, with additional decreases associated with severe asthma and male sex. FVC/iVC ratios< LLN were infrequent in subjects <30 yr but evident in most asthma subjects >50 yr. Lung residual volumes followed similar patterns of greater elevations in subjects with severe asthma, older age, and male sex. Compressive air trapping occurs frequently in older asthmatics, appearing to be a feature of the natural history of asthma that is greater in severe asthma and men. This component of premature airway closure affects spirometric assessment of airway function and may contribute to asthma symptoms during physical exertion. Premature airway closure during exhalation is a component of airway obstruction that is associated with asthma severity and instability. Compressive air trapping is airway closure that is more extensive during a forced exhalation than with a slow, passive exhalation. We report that compressive air trapping occurs in most people > 50 yr with asthma, affects men more than women, and persists after bronchodilator treatment. This component of obstruction appears to be part of the natural history of asthma.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Airway Obstruction; Asthma; Bronchodilator Agents; Child; Female; Forced Expiratory Volume; Humans; Lung; Male; Middle Aged; Plethysmography; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests; Severity of Illness Index; Spirometry; Tidal Volume; Vital Capacity; Young Adult
PubMed: 30844338
DOI: 10.1152/japplphysiol.00924.2018 -
Frontiers in Immunology 2023
Topics: Humans; Thrombosis; Inflammation
PubMed: 37920472
DOI: 10.3389/fimmu.2023.1303385 -
Scientific Reports Nov 2018This study was conducted to evaluate the presence of air trapping in patients with idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs)...
This study was conducted to evaluate the presence of air trapping in patients with idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs) (non-IPF), showing the radiological pattern of usual interstitial pneumonia (UIP). Retrospectively, we included 69 consecutive patients showing the typical UIP pattern on computed tomography (CT), and 15 final diagnosis of IPF with CT pattern "inconsistent with UIP" due to extensive air trapping. Air trapping at CT was assessed qualitatively by visual analysis and quantitatively by automated-software. In the quantitative analysis, significant air trapping was defined as >6% of voxels with attenuation between -950 to -856 HU on expiratory CT (expiratory air trapping index [ATIexp]) or an expiratory to inspiratory (E/I) ratio of mean lung density >0.87. The sample comprised 51 (60.7%) cases of IPF and 33 (39.3%) cases of non-IPF ILD. Most patients did not have air trapping (E/I ratio ≤0.87, n = 53, [63.1%]; ATIexp ≤6%, n = 45, [53.6%]). Air trapping in the upper lobes was the only variable distinguishing IPF from non-IPF ILD (prevalence, 3.9% vs 33.3%, p < 0.001). In conclusion, air trapping is common in patients with ILDs showing a UIP pattern on CT, as determined by qualitative and quantitative evaluation, and should not be considered to be inconsistent with UIP. On subjective visual assessment, air trapping in the upper lobes was associated with a non-IPF diagnoses.
Topics: Aged; Diagnosis, Differential; Female; Humans; Idiopathic Pulmonary Fibrosis; Lung; Lung Diseases, Interstitial; Male; Middle Aged; Prevalence; Prognosis; Radiographic Image Interpretation, Computer-Assisted; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 30467322
DOI: 10.1038/s41598-018-35387-3 -
BMJ Open Respiratory Research Apr 2023The inter-relationships among neutrophilic airway inflammation, air trapping and future exacerbation in chronic obstructive pulmonary disease (COPD) remain unclear.
BACKGROUND
The inter-relationships among neutrophilic airway inflammation, air trapping and future exacerbation in chronic obstructive pulmonary disease (COPD) remain unclear.
OBJECTIVE
To evaluate the associations between sputum neutrophil proportions and future exacerbation in COPD and to determine whether these associations are modified by significant air trapping.
METHODS
Participants with completed data were included and followed up to the first year in the Early Chronic Obstructive Pulmonary Disease study (n=582). Sputum neutrophil proportions and high-resolution CT-related markers were measured at baseline. Sputum neutrophil proportions were dichotomised based on their median (86.2%) to low and high levels. In addition, subjects were divided into the air trapping or non-air trapping group. Outcomes of interest included COPD exacerbation (separately any, severe and frequent exacerbation, occurring in the first year of follow-up). Multivariable logistic regressions were performed to examine the risk of severe exacerbation and frequent exacerbation with either neutrophilic airway inflammation groups or air trapping groups.
RESULTS
There was no significant difference between high and low levels of sputum neutrophil proportions in the exacerbation in the preceding year. After the first year of follow-up, subjects with high sputum neutrophil proportions had increased risks of severe exacerbation (OR=1.68, 95% CI: 1.09 to 2.62, p=0.020). Subjects with high sputum neutrophil proportions and significant air trapping had increased odds of having frequent exacerbation (OR=3.29, 95% CI: 1.30 to 9.37, p=0.017) and having severe exacerbation (OR=2.72, 95% CI: 1.42 to 5.43, p=0.003) when compared with those who had low sputum neutrophil proportions and non-air trapping.
CONCLUSIONS
We found that subjects with high sputum neutrophil proportions and significant air trapping are prone to future exacerbation of COPD. It may be a helpful predictor of future exacerbation.
Topics: Humans; Pulmonary Disease, Chronic Obstructive; Inflammation; Neutrophils
PubMed: 37028910
DOI: 10.1136/bmjresp-2022-001597