Pathological and clinical relevance of selective recruitment of Langerhans cells in the respiratory bronchioles of smokers

BackgroundSmoking causes an influx of inflammatory cells including Langerhans cells (LCs) into the airways and lung parenchyma, thus inducing histological changes, such as emphysema and fibrosis. We examined the distribution and quantity of Langerhans cells in relation to clinical and pathological findings and explored the association between smoking and accumulation of Langerhans cells in the respiratory bronchioles.MethodsFifty-three patients who underwent lung resection for primary diseases, including lung cancer, were recruited. Histological and immunohistochemistry analyses were utilized to identify CD1a-positive Langerhans cells in peripheral lung specimens separated from primary lesions. Clinical characteristics, pathological changes, and distribution of CD1a-positive Langerhans cells distribution were assessed.ResultsOf the 53 patients, 35 were smokers and 18 were non-smokers. The number of Langerhans cells in the respiratory bronchioles was significantly increased in smokers as compared to that in non-smokers (p < 0.001). The number of Langerhans cells in smokers was significantly higher in patients with mild emphysema than in those without emphysema (p < 0.01). The high-LC group showed more frequent smoking-related histological changes, such as respiratory bronchiolitis, parenchymal fibrosis, accumulation of macrophages, and smoking-related interstitial fibrosis, than the low-LC group. However, there were no differences in the smoking indices and pulmonary functions of the groups.ConclusionsSelective accumulation of Langerhans cells in the respiratory bronchioles of smokers may lead to the development of smoking-related pathological changes.     

Outcomes and predictive factors for successful smoking cessation therapy in COPD patients with nicotine dependence

BackgroundThe data on smoking cessation treatment outcomes for smokers with chronic obstructive pulmonary disease (COPD) are limited. The present study assessed the effectiveness of smoking cessation interventions at our clinic.MethodsData from a prospective registry of a 3-month smoking cessation program were evaluated. The primary outcome, smoking cessation, was defined as the complete abstinence from smoking between the 8-week and 12-week clinic visits. Pulmonary function and health-related quality of life using St. George's Respiratory Questionnaire (SGRQ) were assessed at baseline and at the end of the program.ResultsOut of the 155 COPD patients with nicotine dependence (female/male = 39/116; mean age, 67.2 ± 9.8 years; mean forced expiratory volume in 1 s (FEV1), 59.7 ± 21.1% predicted), 107 participants completed the program. Among the completers, 74 achieved smoking cessation. In the multivariate analysis, mental disorders (odds ratio [OR] 3.678, 95% confidence interval [CI]: 1.182, 11.445), higher exhaled carbon monoxide (CO) level (OR 1.080, 95% CI: 1.013, 1.151) and lower FEV1/forced vital capacity (FVC) (OR 0.958, 95% CI: 0.923, 0.995) were negatively associated with successful smoking termination. Significant changes in pulmonary function were found in quitters but not in continuous smokers (increases in FEV1 by 0.09 L/s [95% CI: 0.03, 0.15] and peak expiratory flow by 0.23 L/s [95% CI: 0.01, 0.44]). SGRQ total scores improved significantly in both quitters (−5.4 [95% CI: −8.4, −2.5]) and continuous smokers (−7.0 [95% CI: −11.6, −2.5]).ConclusionIn the program completers, the exhaled CO levels, FEV1/FVC ratio, and presence of mental disorders were significantly associated with program success or failure in COPD patients with nicotine dependence.     

Mechanisms Underlying the Association of Chronic Obstructive Pulmonary Disease With Heart Failure

ObjectivesThe purposes of this study were to determine why chronic obstructive pulmonary disease (COPD) is associated with heart failure (HF). Specific objectives included whether COPD is associated with myocardial fibrosis, whether myocardial fibrosis is associated with hospitalization for HF and death in COPD, and whether COPD and smoking are associated with myocardial inflammation.BackgroundCOPD is associated with HF independent of shared risk factors. The underlying pathophysiological mechanism is unknown.MethodsA prospective, multicenter, longitudinal cohort study of 572 patients undergoing cardiac magnetic resonance (CMR), including 450 patients with COPD and 122 age- and sex-matched patients with a median: 726 days (interquartile range: 492 to 1,160 days) follow-up. Multivariate analysis was used to examine the relationship between COPD and myocardial fibrosis, measured using cardiac magnetic resonance (CMR). Cox regression analysis was used to examine the relationship between myocardial fibrosis and outcomes; the primary endpoint was composite of hospitalizations for HF or all-cause mortality; secondary endpoints included hospitalizations for HF and all-cause mortality. Fifteen patients with COPD, 15 current smokers, and 15 healthy volunteers underwent evaluation for myocardial inflammation, including ultrasmall superparamagnetic particles of iron oxide CMR.ResultsCOPD was independently associated with myocardial fibrosis (p < 0.001). Myocardial fibrosis was independently associated with the primary outcome (hazard ratio [HR]: 1.14; 95% confidence interval [CI]: 1.08 to 1.20; p < 0.001), hospitalization for HF (HR: 1.25 [95% CI: 1.14 to 1.36]); p < 0.001), and all-cause mortality. Myocardial fibrosis was associated with outcome measurements more strongly than any other variable. Acute and stable COPD were associated with myocardial inflammation.ConclusionsThe associations between COPD, myocardial inflammation and myocardial fibrosis, and the independent prognostic value of myocardial fibrosis elucidate a potential pathophysiological link between COPD and HF.     

Lobar distribution of non-emphysematous gas trapping and lung hyperinflation in chronic obstructive pulmonary disease

BackgroundLung hyperinflation in chronic obstructive pulmonary disease (COPD) is closely associated with emphysema and non-emphysematous gas trapping, termed functional small airway disease (fSAD), on inspiratory and expiratory computed tomography (CT). Because the cranial-caudal emphysema distribution affects pulmonary function and fSAD may precede emphysema on CT, we tested the hypothesis that lobar fSAD distribution would affect lung hyperinflation differently in COPD with minimal and established emphysema.MethodsThe volume percentages of fSAD and emphysema (fSAD% and Emph%) over the upper and lower lobes were measured using inspiratory and expiratory CT in 70 subjects with COPD. Subjects were divided into those with minimal and established emphysema (n = 36 and 34) using a threshold of 10% Emph% in the whole lung.ResultsIn the minimal emphysema group, fSAD% in the upper and lower lobes was positively correlated with functional residual capacity (FRC) and residual volume to total lung capacity ratio (RV/TLC), and the correlation of fSAD% with RV/TLC was greater in the lower lobes. Conversely, in the established emphysema group, fSAD% in the upper and lower lobes was correlated with RV/TLC, but not with FRC. In multivariate analysis, fSAD% in the lower lobes, but not in the upper lobes, was associated with RV/TLC in subjects with minimal emphysema after adjusting for age, smoking status, and bronchodilator use.ConclusionNon-emphysematous gas trapping in the upper and lower lobes has a distinct physiological effect, especially in COPD with minimal emphysema. This local evaluation might allow sensitive detection of changes in lung hyperinflation in COPD.     

High prevalence of airway obstruction and pulmonary emphysema in urothelial (renal pelvis,ureter, and bladder) cancer patients

BackgroundCigarette smoking is a major cause of COPD, with patients also presenting complications that stem from other smoking-related diseases, including urothelial cancer. However, the prevalence of COPD or airflow obstruction in urothelial cancer patients has not been well studied.MethodsWe investigated the prevalence of airflow obstruction (FEV1/FVC < 70%) in newly diagnosed urothelial cancer patients and identified the risk factors for airflow obstruction in existing urothelial cancer patients. Additionally, we compared the characteristics of subjects who had been diagnosed with both airflow obstruction and urothelial cancer, and subjects whose airflow obstruction was discovered during health screenings.ResultsA total of 217 patients were newly diagnosed with urothelial cancer during the study period at our institution. Among all patients, 210 (96.8%) underwent an evaluable lung function test, in which 38.6% (81 patients) displayed airflow obstruction defined as FEV1/FVC < 70%. In urothelial cancer patients, age, smoking index (pack-years), and BMI proved to be significant risk factors for airflow obstruction in multivariate logistic regression (p = 0.007, p < 0.0001, and p = 0.035, respectively). Gender, cancer stage, and cancer location were not significant risk factors. Patients with both airflow obstruction and urothelial cancer showed a more advanced emphysematous change than subjects presenting with airflow obstruction alone (unpaired t-test, p = 0.0003).ConclusionsAirflow obstruction was identified in 38.6% of urothelial cancer patients. Age, smoking index (pack-years), and BMI were significant risk factors. A significantly higher emphysematous score was observed in subjects with urothelial cancer than in subjects with airway obstruction alone.     

Blood eosinophil count variability in chronic obstructive pulmonary disease and severe asthma

BackgroundBlood eosinophils are essential biomarkers that vary substantially over time in patients with COPD and asthma. However, no study has identified the changes and effects in the changes of the blood eosinophil counts over time in both diseases. This study aimed to demonstrate blood eosinophil variability in patients with COPD and severe asthma based on these backgrounds.MethodsA total of 172 patients with COPD from the Hokkaido COPD cohort study and 96 patients with severe asthma from the Hokkaido Severe Asthma Cohort Study, whose blood eosinophil counts were measured annually over a 3-year period, were analyzed. The factors contributing to consistently high or low blood eosinophil counts were examined in each cohort. The stability of the eosinophil classification (<150, 150–299, ≥300 cells/μL) was compared based on the number of asthma-like features in patients with COPD and the smoking status in patients with severe asthma.ResultsAmong all the patients, the most stable range of baseline blood eosinophil counts differed between the two diseases, with <150 cells/μL in COPD and ≥300 cells/μL in severe asthma. In COPD, the number of asthma-like features (bronchodilator reversibility, blood eosinophilia, and atopy) affects the blood eosinophil count variation patterns. In severe asthma, smoking status did not affect the blood eosinophil count variation patterns.ConclusionsWe identified variations in the blood eosinophil counts and their contributing factors in patients with COPD and severe asthma.     

Mechanical ventilation for acute exacerbation of fibrosing interstitial lung diseases

BackgroundAcute exacerbation of fibrosing interstitial lung diseases, including idiopathic pulmonary fibrosis, is associated with poor prognosis. Accordingly, tracheal intubation and invasive mechanical ventilation are generally avoided in such patients. However, the efficacy of invasive mechanical ventilation for acute exacerbation of fibrosing interstitial lung diseases remains unclear. Therefore, we aimed to investigate the clinical course of patients with acute exacerbation of fibrosing interstitial lung diseases who were treated with invasive mechanical ventilation.MethodsWe retrospectively analyzed 28 patients with acute exacerbation of fibrosing interstitial lung diseases who underwent invasive mechanical ventilation at our hospital.ResultsOf the 28 included patients (20 men, 8 women; mean age, 70.6 years), 13 (46.4%) were discharged alive and 15 died. Ten patients (35.7%) had idiopathic pulmonary fibrosis. Univariate analysis revealed that longer survival was significantly associated with lower partial pressure of arterial carbon dioxide (hazard ratio [HR] 1.04 [1.01–1.07]; p = 0.002) and higher pH (HR 0.0002 [0–0.02] levels; p = 0.0003) and less severe general status according to the Acute Physiology and Chronic Health Evaluation II score (HR 1.13 [1.03–1.22]; p = 0.006) at the time of mechanical ventilation initiation. In addition, the univariate analysis indicated that patients without long-term oxygen therapy use had significantly longer survival (HR 4.35 [1.51–12.52]; p = 0.006).ConclusionsInvasive mechanical ventilation may effectively treat acute exacerbation of fibrosing interstitial lung diseases if good ventilation and general conditions can be maintained.     

Small airway disease and its predictors in patients with rheumatoid arthritis

BackgroundRheumatoid arthritis (RA) is a connective tissue disease, characterized by symmetric peripheral polyarthritis. Extra-articular disease occurs in approximately 50% of the patients with lung being a common site. The presence of functional or morphological abnormalities in small airways has recently been noted in patients with RA but its exact prevalence and clinical significance is still a subject of debate. This study was aimed to determine the prevalence of small airway disease (SAD) in patients with RA and the factors influencing it.MethodsFifty consecutive patients with RA were included in this cross-sectional observational study. All patients were subjected to pulmonary function tests (PFT) including Spirometry and Forced Oscillation technique (FOT). Those with features of SAD on PFT were subjected to High-Resolution Computed Tomography (HRCT) of the chest.ResultsSpirometry was suggestive of SAD in 17 patients, with 34% prevalence and FOT was abnormal in 9 patients, with 18% prevalence in the study population. Of 17 patients with SAD on spirometry, 8 (47.05%) patients showed mosaic attenuation, a sign of SAD on the HRCT chest. On univariate analysis, age, Disease Activity Score (DAS-28), joint erosions on X-ray, RF and anti-CCP were found to be associated with SAD.ConclusionSAD was present in one-third of the patients with RA, even in those with short duration of disease, low to moderate disease activity and no respiratory symptoms. It is thus inferred that the complete workup of RA patients should include pulmonary function assessment.     

The prevalence of comorbid respiratory disease among COVID-19 patients,and mortality during the first wave in Japan: A nationwide survey by the Japanese Respiratory Society

There is a concern that persons with underlying respiratory disease may have increased susceptibility to COVID-19 and/or increased severity/mortality if infected. However, information regarding such patients during the first wave of the epidemic is lacking in Japan. We surveyed chest physicians nationwide, and collected anonymous data concerning 1444 patients.Among COVID-19 patients, the prevalence of asthma, chronic obstructive pulmonary disease (COPD), and interstitial lung diseases (ILD) was 3.4%, 4.8%, and 1.5%, respectively. Among COVID-19 patients with these 3 comorbidities, exacerbation of the comorbidity occurred in 12.2%, 18.8%, and 36.4%, respectively, and mortality (6.2% overall) was 4.1%, 13.0%, and 31.8%, respectively.The prevalence of asthma among COVID-19 patients was not higher than that for the general population, and mortality in COVID-19 patients with asthma was not higher than mortality in COVID-19 patients without underlying respiratory disease. COVID-19 patients having COPD or ILD had relatively high mortality, especially for ILD.     

Airway involvement in inflammatory bowel disease: Inflammatory bowel disease patients have bronchial wall thickening

BackgroundRecent epidemiological studies have revealed a high co-occurrence of asthma or COPD and IBD. Herein, we examined the impact of IBD on the bronchial wall structure using three-dimensional computed tomography (3D-CT).MethodsSubjects who were diagnosed with IBD and had undergone chest CT were recruited from consecutive medical records. Screening chest CT scan data during the same period were used as normal controls. Airway dimensions were measured by validated software.ResultsOverall, 136 IBD and 99 control subjects were recruited. The bronchial walls of patients with IBD were significantly thicker than those of control subjects. Multiple linear regression analysis showed that Crohn's disease and ulcerative colitis were independent determinants of wall area percentage after adjusting for age, sex, and smoking status.ConclusionsAirway walls in patients with IBD were thicker than those in normal control subjects. Airway involvement in IBD may be more frequent than recognized.     

Clinical,radiological, and pathological features of anti-asparaginyl tRNA synthetase antibody-related interstitial lung disease

BackgroundMyositis and interstitial lung disease (ILD) frequently occur in patients with anti-aminoacyl-tRNA synthetase (ARS) antibodies. Nearly half of ARS-ILD patients have the acute or subacute form of the disease, and one-third of these patients show a deterioration in pulmonary function over the long-term course because of frequent recurrences and refractoriness to therapy. Several reports recently described different characteristics depending on the individual anti-ARS antibodies, and the anti-asparaginyl tRNA synthetase (KS) antibody was strongly linked to ILD rather than to myositis. We therefore hypothesized that KS-ILD may have clinical characteristics that differ from those of other ARS-ILDs. The aim of this study was to clarify the clinical, radiological, and pathological features of KS antibody-positive ILD.MethodsWe retrospectively analyzed 19 consecutive patients with KS-ILD who underwent initial clinical measurements and high-resolution computed tomography and pathological assessments. We also analyzed disease behavior based on pulmonary function test results during the follow-up period.ResultsOur KS-ILD cohort included patients with dermatomyositis (10.5%), primary Sjögren syndrome (5.3%), and idiopathic ILD (84.2%). Most patients presented with chronic onset (89.5%) and a nonspecific pattern of interstitial pneumonia at each radiological and pathological assessment (89.4% and 85.7%, respectively). The pulmonary function test results showed that the mean changes from the initial %forced vital capacity and %diffusing capacity of the lung for carbon monoxide at 3 years were 3.7% ± 2.9% and 9.35% ± 3.0%, respectively.ConclusionsMost KS-ILD patients showed a tendency for chronic disease onset and long-term stabilization of pulmonary function.     

Influence of dietary total antioxidant capacity on the association between smoking and hypertension in Brazilian graduates (CUME project)

Background and aimsHypertension (HTN) is a chronic non-communicable disease influenced by non-modifiable risk factors, such as sex and age, as well as modifiable risk factors such as lifestyle, including diet and smoking. Moreover, diet quality among smokers is worse than that of non-smokers, mainly in terms of antioxidant content. Thus, the current study aimed to investigate whether dietary total antioxidant capacity (dTAC) influences the association between smoking and HTN.Methods and resultsThis cross-sectional study included 4303 graduates (69.35% women) from the Cohort of Minas Gerais Universities (CUME) project. An online food frequency questionnaire was administered to participants, and dTAC was estimated using the ferric reducing antioxidant power method. In the questionnaires, individuals reported smoking status, systolic and diastolic blood pressure values, previous HTN diagnosis, and use of antihypertensive drugs. Logistic regression models were used to estimate the odds ratio and 95% confidence interval between smoking and HTN, stratified by the median dTAC. Current and former smokers had higher dTAC values despite their lower fruit intake. Moreover, coffee was the main contributor to dTAC among them. Smoking was associated with a higher likelihood of HTN, mainly among individuals with a higher dTAC. However, after exclusion of coffee antioxidant capacity, there was an association between only smoking and HTN in individuals with lower dTAC.ConclusionsThe controversial association between higher dTAC and HTN can result from high coffee intake. Higher dTAC without coffee intake may mitigate the association between smoking and HTN in this population.     

Correlation of 4-meter gait speed with clinical indicators of chronic obstructive pulmonary disease

BackgroundMeasuring daily physical activity and exercise capacity is recommended in the routine care of patients with chronic obstructive pulmonary disease (COPD). The 4-m gait speed (4mGS) is simple and effective in stratifying patients according to exercise performance, dyspnea, health status, and prognosis. We assessed the reliability of the 4mGS as a clinical marker by examining its association with established clinical indicators among hospitalized patients with COPD.MethodsThis retrospective study included 78 patients hospitalized with COPD (mean age: 76.3 ± 0.9 years; males, n = 69) between January 2016 and June 2018 who were assessed using the 4mGS and divided into slow (<0.8 m/s) and normal (≥0.8 m/s) 4mGS groups. Clinical characteristics were compared, including death during the observation period, time to first exacerbation, and long-term oxygen therapy requirement.ResultsThere were strong relationships between 4mGS performance, the 6-min walk test (R = 0.70; p < 0.0001), and the modified Medical Research Council dyspnea scale (R = 0.68; p < 0.0001) among the 78 patients. The slow 4mGS group had a higher frequency of death during the observation period (p = 0.0095) and a greater requirement for long-term oxygen therapy (p = 0.0063). The 4mGS correlated with inspiratory capacity (IC) and IC/total lung capacity ratios, which are respiratory failure indicators.ConclusionsThe 4mGS is a simple and easy method of assessing the physical condition as well as estimating the prognosis of patients with COPD, and may serve as a useful marker in home medical treatment or clinical settings.     

Subclinical Pulmonary Congestion and Abnormal Hemodynamics in Heart Failure With Preserved Ejection Fraction

ObjectivesThe authors hypothesized that quantitative computed tomography (QCT) imaging would reveal subclinical increases in lung congestion in patients with heart failure and preserved ejection fraction (HFpEF) and that this would be related to pulmonary vascular hemodynamic abnormalities.BackgroundGross evidence of lung congestion on physical examination, laboratory tests, and radiography is typically absent among compensated ambulatory patients with HFpEF. However, pulmonary gas transfer abnormalities are commonly observed and associated with poor outcomes.MethodsPatients referred for invasive hemodynamic exercise testing who had undergone chest computed tomography imaging within 1 month were identified (N = 137). A novel artificial intelligence QCT algorithm was used to measure pulmonary fluid content.ResultsCompared with control subjects with noncardiac dyspnea, patients with HFpEF displayed increased mean lung density (–758 HU [–793, –709 HU] vs –787 HU [–828, –747 HU]; P = 0.002) and a higher ratio of extravascular lung water to total lung volume (EVLWV/TLV) (1.25 [0.80, 1.76] vs 0.66 [0.01, 1.03]; P < 0.0001) by QCT imaging, indicating greater lung congestion. EVLWV/TLV was directly correlated with pulmonary vascular pressures at rest, with stronger correlations observed during exercise. Patients with increasing tertiles of EVLWV/TLV demonstrated higher mean pulmonary artery pressures at rest (34 ± 11 mm Hg vs 39 ± 14 mm Hg vs 45 ± 17 mm Hg; P = 0.0003) and during exercise (55 ± 17 mm Hg vs 59 ± 17 mm Hg vs 69 ± 22 mm Hg; P = 0.0003).ConclusionsQCT imaging identifies subclinical lung congestion in HFpEF that is not clinically apparent but is related to abnormalities in pulmonary vascular hemodynamics. These data provide new insight into the long-term effects of altered hemodynamics on pulmonary structure and function in HFpEF.     

The efficacy of mass screening for chronic obstructive pulmonary disease using screening questionnaires in a medical health check-up population

BackgroundChronic obstructive pulmonary disease (COPD) is a preventable and treatable disease, highlighting the need for efficient screening strategies to identify patients with COPD. However, there is little evidence regarding the efficacy of mass screening for COPD, and no epidemiological studies on COPD have been conducted in the Shikoku region of Japan.MethodsIn this cross-sectional study, we originally investigated the efficacy of mass screening for COPD among community residents in the aforementioned region using two COPD screening questionnaires.ResultsFrom July 2018 through January 2019, 688 participants were enrolled. COPD was diagnosed using the Global Initiative for the Chronic Obstructive Lung Disease criteria. Twenty-one patients were newly diagnosed with COPD and 19 (90.5%) had early stages COPD. The prevalence of COPD in this study was 3.1%. The COPD Population Screener (COPD-PS) questionnaire and the International Primary Care Airways Guidelines (IPAG) questionnaire had extremely high negative predictive values in discriminating participants with COPD from those without. The scores of both questionnaires were correlated with spirometric tests and with each other. The COPD-PS questionnaire had significantly better specificity and area under the receiver operating characteristic curve value than the IPAG questionnaire. Moreover, only the COPD-PS questionnaire was identified as an independent factor for predicting COPD diagnosis in the multivariate analysis.Conclusions: Mass screening for COPD using screening questionnaires, particularly the COPD-PS questionnaire, might be useful to identify the early stages of COPD in a medical health check-up population.     

The prognostic value of the COPD Assessment Test in fibrotic interstitial lung disease

BackgroundThe COPD Assessment Test (CAT) has been studied as a measure of health status in idiopathic pulmonary fibrosis (IPF) and interstitial lung disease associated with connective tissue disease. However, its prognostic value is unknown. The present study explored the association between CAT score and mortality in fibrotic interstitial lung disease (FILD), including IPF and other forms of ILD.MethodsWe retrospectively analyzed 501 consecutive patients with FILD who underwent clinical assessment, including pulmonary function test and CAT. The association between CAT score and 3-year mortality was assessed using Cox proportional hazard analysis, Kaplan–Meier plots, and the log-rank test for trend. To handle missing data, the imputed method was used.ResultsThe patients’ median age was 68 years, and 320 were male (63.9%). Regarding CAT severity, 203 patients had a low impact level (score <10), 195 had a medium level (10–20), 80 had a high level (21–30), and 23 had a very high level (31–40). During the 3-year study period, 118 patients died. After adjusting for age, sex, forced vital capacity, diffusion capacity for carbon monoxide, IPF diagnosis, and usual interstitial pneumonia pattern on high-resolution computed tomography, the CAT score was significantly associated with 3-year mortality (hazard ratio in increments of 10 points: 1.458, 95% confidence interval 1.161–1.830; p < 0.001). In addition, patients with high and very high impact levels had twofold and threefold higher mortality risk than those with low levels, respectively.ConclusionThe CAT has prognostic value in FILD.     

Increased LHX9 expression in alveolar epithelial type 2 cells of patients with chronic obstructive pulmonary disease

BackgroundAlveolar epithelial type 2 (AT2) cells serve as stem cells in alveolar epithelium and are assumed to lose their stem cell function in the lungs of chronic obstructive pulmonary disease (COPD). Although we previously reported that LHX9 mRNA expression was up-regulated in AT2 cells of COPD lung tissues, it is yet to be elucidated how LHX9 is associated with the vulnerability of AT2 cells in COPD.MethodsAT2 cells were isolated from lung tissues of 10 non-COPD subjects and 11 COPD patients. LHX9 mRNA expression was determined by quantitative RT-PCR. To identify up-stream molecules, an alveolar epithelial cell line A549 was exposed to pro-inflammatory cytokines in vitro. siRNA-mediated Lhx9 knockdown was performed to determine how Lhx9 affected the cellular viability and the cell-division cycle.ResultsLHX9 mRNA expression was increased in AT2 cells from COPD lung tissues, compared to those from non-COPD tissues. The airflow obstruction was independently correlated with the increase in LHX9 expression. Among several pro-inflammatory cytokines, interferon-γ was a strong inducer of LHX9 expression in A549 cells. Lhx9 was involved in the increased susceptibility to serum starvation-induced death of A549 cells.ConclusionsOur data suggest that IFN-γ predominantly increases the LHX9 expression which enhances the susceptibility to cell death. Considering the independent association of the increased LHX9 expression in AT2 cells with airflow obstruction, the IFN-γ-Lhx9 axis might contribute to the vulnerability of AT2 cells in the lungs of COPD patients.     

Differential role of mucus plugs in asthma: Effects of smoking and association with airway inflammation

BackgroundThe physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical–physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma.MethodsA total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT.ResultsMore mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics.ConclusionsThe association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma.     

Clinical features of organizing pneumonia in anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorders

BackgroundAnti-aquaporin-4 (AQP4) antibody is an autoantibody marker often observed in patients with neuromyelitis optica spectrum disorder (NMOSD). The pathological relevance of complicated pulmonary disorders in anti-AQP4 antibody-positive NMOSD remains unclear. We aimed to assess the clinical and histological relevance of complicated pulmonary disorders in anti-AQP4 antibody-positive NMOSD.MethodsWe retrospectively reviewed the medical records of 52 patients with anti-AQP4 antibody-positive NMOSD and conducted immunohistochemical evaluations of the lung biopsy specimens.ResultsAmong 52 patients with anti-AQP4 antibody-positive NMOSD, 4 patients showed pulmonary involvement with a diagnosis of organizing pneumonia (OP). The proportion of males was larger (75% vs. 12.5%; p = 0.013) and creatine kinase levels were higher (458.3 U/L vs. 83.9 U/L; p = 0.003) in patients with OP than in those without OP. OP development preceded or coincided with the NMOSD symptoms. Chest computed tomography findings were consistent with OP in all four patients. Bronchoalveolar lavage fluid predominantly contained lymphocytes. Transbronchial lung biopsy revealed intraluminal plugs of inflammatory debris within the alveoli. Alveolar epithelial cells covering the OP lesions exhibited AQP4 loss, immunoglobulin G deposition, and complement activation. Corticosteroid treatment resulted in clinical improvement of OP.ConclusionOP may be considered a pulmonary manifestation of anti-AQP4 antibody-positive NMOSD beyond the central nervous system. Complement-dependent cytotoxicity of the lung epithelial cells caused by anti-AQP4 antibody is at least partly involved in OP development. When diagnosing NMOSD, the possibility of OP should be carefully evaluated based on the detailed history and chest imaging findings.