Small Airways Research Articles

Single-cell resolution of human airway epithelial cells exposed to bronchiolitis obliterans-associated chemicals.

Bronchiolitis obliterans (BO) is a fibrotic lung disease characterized by progressive luminal narrowing and obliteration of the small airways. In the nontransplant population, inhalation exposure to certain chemicals is associated with BO; however, the mechanisms contributing to disease induction remain poorly understood. This study's objective was to use single-cell RNA sequencing for the identification of transcriptomic signatures common to primary human airway epithelial cells after chemical exposure to BO-associated chemicals-diacetyl or nitrogen mustard-to help explain BO induction. Primary airway epithelial cells were cultured at air-liquid interface and exposed to diacetyl, nitrogen mustard, or control vapors. Cultures were dissociated and sequenced for single-cell RNA. Differential gene expression and functional pathway analyses were compared across exposures. In total, 75,663 single cells were captured and sequenced from all exposure conditions. Unbiased clustering identified 11 discrete phenotypes, including 5 basal, 2 ciliated, and 2 secretory cell clusters. With chemical exposure, the proportion of cells assigned to keratin 5+ basal cells decreased, whereas the proportion of cells aligned to secretory cell clusters increased compared with control exposures. Functional pathway analysis identified interferon signaling and antigen processing/presentation as pathways commonly upregulated after diacetyl or nitrogen mustard exposure in a ciliated cell cluster. Conversely, the response of airway basal cells differed significantly with upregulation of the unfolded protein response in diacetyl-exposed basal cells, not seen in nitrogen mustard-exposed cultures. These new insights provide early identification of airway epithelial signatures common to BO-associated chemical exposures.NEW & NOTEWORTHY Bronchiolitis obliterans (BO) is a devastating fibrotic lung disease of the small airways, or bronchioles. This original manuscript uses single-cell RNA sequencing for identifying common signatures of chemically exposed airway epithelial cells in BO induction. Chemical exposure reduced the proportion of keratin 5+ basal cells while increasing the proportion of keratin 4+ suprabasal cells. Functional pathways contributory to these shifts differed significantly across exposures. These new results highlight similarities and differences in BO induction across exposures.

Children with severe asthma have substantial structural airway changes on computed tomography.

In adults with severe asthma (SA) bronchial wall thickening, bronchiectasis and low attenuation regions (LAR) have been described on chest computed tomography (CT) scans. The extent to which these structural abnormalities are present in children with SA is largely unknown. Our aim was to study the presence and extent of airway abnormalities on chest CT of children with SA. 161 inspiratory and expiratory CT scans, either spirometer-controlled or technician-controlled, obtained in 131 children with SA (mean±SD age 11.0±3.8 years) were collected retrospectively. Inspiratory scans were analysed manually using a semi-quantitative score and automatically using LungQ (v2.1.0.1; Thirona B.V., Nijmegen, the Netherlands). LungQ segments the bronchial tree, identifies the generation for each bronchus-artery (BA) pair and measures the following BA dimensions: outer bronchial wall diameter (Bout), adjacent artery diameter (A) and bronchial wall thickness (Bwt). Bronchiectasis was defined as Bout/A ≥1.1, bronchial wall thickening as Bwt/A ≥0.14. LAR, reflecting small airways disease (SAD), was measured automatically on inspiratory and expiratory scans and manually on expiratory scans. Functional SAD was defined as FEF25-75 and/or FEF75 z-scores <-1.645. Results are shown as median and interquartile range. Bronchiectasis was present on 95.8% and bronchial wall thickening on all CTs using the automated method. Bronchiectasis was present on 28% and bronchial wall thickening on 88.8% of the CTs using the manual semi-quantitative analysis. The percentage of BA pairs defined as bronchiectasis was 24.62% (12.7-39.3%) and bronchial wall thickening was 41.7% (24.0-79.8%) per CT using the automated method. LAR was observed on all CTs using the automatic analysis and on 82.9% using the manual semi-quantitative analysis. Patients with LAR or functional SAD had more thickened bronchi than patients without. Despite a large discrepancy between the automated and the manual semi-quantitative analysis, bronchiectasis and bronchial wall thickening are present on most CT scans of children with SA. SAD is related to bronchial wall thickening.

Small Airway Disease in Pre-Chronic Obstructive Pulmonary Disease with Emphysema: A Cross-Sectional Study.

Rationale: Small airway disease is an important pathophysiological feature of chronic obstructive pulmonary disease (COPD). Recently, "pre-COPD" has been put forward as a potential precursor stage of COPD that is defined by abnormal spirometry findings or significant emphysema on computed tomography (CT) in the absence of airflow obstruction. Objective: To determine the degree and nature of (small) airway disease in pre-COPD using microCT in a cohort of explant lobes/lungs. Methods: We collected whole lungs/lung lobes from patients with emphysematous pre-COPD (n = 10); Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I (n = 6), II (n = 6), and III/IV (n = 7) COPD; and controls (n = 10), which were analyzed using CT and microCT. The degree of emphysema and the number and morphology of small airways were compared between groups, and further correlations were investigated with physiologic measures. Airway and parenchymal pathology was also validated with histopathology. Measurements and Main Results: The numbers of transitional bronchioles and terminal bronchioles per milliliter of lung were significantly lower in pre-COPD and GOLD stages I, II, and III/IV COPD compared with controls. In addition, the number of alveolar attachments of the transitional bronchioles and terminal bronchioles was also lower in pre-COPD and all COPD groups compared with controls. We did not find any differences between the pre-COPD and COPD groups in CT or microCT measures. The percentage of emphysema on CT showed the strongest correlation with the number of small airways in the COPD groups. Histopathology showed an increase in the mean chord length and a decrease in alveolar surface density in pre-COPD and all GOLD COPD stages compared with controls. Conclusions: Lungs of patients with emphysematous pre-COPD already show fewer small airways and airway remodeling even in the absence of physiologic airway obstruction.

Does Mild Coronavirus Disease 2019 Pneumonia in Healthy Adults Cause Permanent Small Airway Injury?

Impulse oscillometry (IOS) is a type of oscillation technique that measures the input impedance (Z) of the respiratory system and can be used to detect pathological changes in the small airways at an early stage. Although coronavirus disease 2019 (COVID-19) affects the vascular and parenchymal structures in the lung, chronic postinfection coughs also may be attributed to small airway pathologies. Our research aimed to use IOS for the assessment of the presence of small airway resistance (R) in patients who have had COVID-19. Thirty-eight patients with past COVID-19 infections and without any presence or medical treatment of an airway disease who presented to the post-COVID outpatient clinic with coughing symptoms were included in the study. The control group consisted of 17 patients with no past COVID-19 infection and without an airway disease. IOS and spirometry were performed twice in the case group, at 3 and 6 months after COVID-19. The mean age of the case group was 44.7 ± 12.3 years, whereas the mean age of the control group was 49.4 ± 11.8 years. The case group consisted of 38 patients, whereas 17 patients constituted the control group. No statistically significant difference was found between the two groups in the first and second test measurements, performed 3 months apart (P > 0.05). The fact that there was no difference between respiratory system impedance, airway resistance, and spirometry values between groups with and without past COVID-19 infections supported the hypothesis that small airways were not affected 3 months after COVID-19.

A MULTISCALE MULTIPHYSICS FINITE ELEMENT FOR LUNG

The previously formulated finite element for lung mechanics (MSCL) by the author is extended to include airflow and molecular transport by diffusion. The lung mechanics is analyzed in detail providing an insight into the deformation of the microstructural elements. Also, some refinements are introduced with respect to the previous model. Here, the finite element is extended to incorporate airflow and convective-diffusive particulate (molecular) transport. The smeared concept (the Kojic Transport Model – KTM) is implemented with lung small airway generations considered as subdomains within the KTM. The subdomains refer to a selected number of generations according to the airway diameters. Each domain has its own volumetric fraction and transport tensor specified in terms of the airway size. The computational procedure implemented in the PAK-BIO software consists of three passes within each time step: mechanics, airflow, and diffusion. The current geometry is used for the airflow where the alveolar sacs are considered as the source terms for the last domain, according to the rate of volumetric deformation and volumetric fraction of the sacs. The pressure distribution calculated in the pass 2 is used for the convective term in the diffusion. Here, the alveolar sacs are included as the last subdomain. The new element is now termed the General Lung Finite Element (GLFE). Coupling airflow in large airways, governed by the Navier-Stokes equations, to small airways (with the Hagen-Poiseuille equations) is presented; the same coupling is given for diffusion. Numerical examples illustrate the generality of the formulated finite element.

Fitness for Work in the Long Journey of Tuberculosis Infection to Chronic Posttuberculosis Disease Case Report and Literature Review

Abstract The long journey of tuberculosis (TB) from exposure to latent or progressive TB infection, from primary stage to second stage of illness with or without infectious status, and then to chronic post-TB sequelae is very complex and still unclear, including a various spectrum of stages and manifestations. A case report of a 55 year-old woman with personal history of pleural effusion, in her youth, 2 previous episodes of COVID-19 infections, having no exposure to active smoking but occupational exposure to wood dust, hot steam, barbeque smoke, was admitted to Constanta Clinical Pneumology Hospital in October 2022 for hemoptysis and fatigue. Clinical and paraclinical investigations highlighted an acute evolutive episode of Pulmonary TB with metastatic bilateral nodular pattern, negative smears, positive cultures and positive QuantiFERON TB Gold in Tube (QFT-GIT). TB standard regimen of therapy was started, based on QFT-GIT positivity, and after it ended, chronic obstructive pulmonary disease was detected by spirometry and small airways dysfunction by impulse oscillometry. TB illness does not stop after directly observed therapy ends. So, systematical screening of pulmonary, bronchial or pleural sequelae should be performed and identified syndromes need to be treated, as well as reintegration in the job process by a careful monitoring.

The Neutralization of the Eosinophil Peroxidase Antibody Accelerates Eosinophilic Mucin Decomposition.

Eosinophilic airway inflammation, complicated by bronchial asthma and eosinophilic chronic rhinosinusitis (ECRS), is difficult to treat. The disease may become refractory when eosinophilic mucin associated with eosinophil peroxidase (EPX) and autoantibodies fills in the paranasal sinus and small airway. This study investigated the functional role of an anti-EPX antibody in eosinophilic mucin of ECRS in eosinophilic airway inflammation. Eosinophilic mucin was obtained from patients with ECRS. The effects of the anti-EPX antibody on dsDNA release from eosinophils and eosinophilic mucin decomposition were evaluated. Immunofluorescence or enzyme-linked immunosorbent assays were performed to detect the anti-EPX antibody and its supernatant and serum levels in eosinophilic mucin, respectively. The serum levels of the anti-EPX antibody were positively correlated with sinus computed tomography score and fractionated exhaled nitrogen oxide. Patients with refractory ECRS had higher serum levels of the anti-EPX antibody than those without. However, dupilumab treatment decreased the serum levels of the anti-EPX antibody. Immunoglobulins (Igs) in the immunoprecipitate of mucin supernatants enhanced dsDNA release from eosinophils, whereas the neutralization of Igs against EPX stopped dsDNA release. Furthermore, EPX antibody neutralization accelerated mucin decomposition and restored corticosteroid sensitivity. Taken together, the anti-EPX antibody may be involved in the formulation of eosinophilic mucin and be used as a clinical marker and therapeutic target for intractable eosinophilic airway inflammation.

Current smoking reduces small airway eosinophil counts in COPD.

Current smoking reduces small airway intraepithelial eosinophil counts in COPD patients and controls. This provides evidence of an attenuation of type-2 related inflammation in the small airways imposed by current smoking, which may affect ICS response. https://bit.ly/49YSKwG.

Mesenchymal Stromal Cell Infusion Might Improve Bronchiolitis Obliterans after Allogeneic Hematopoietic Stem Cell Transplantation and Modulate Alveolar Macrophages in Mice

Some studies suggested that mesenchymal stromal cell (MSC) infusion might improve bronchiolitis obliterans (BO) in patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the underlying mechanism is little known. In this study, we investigated whether MSC infusion could improve BO after allo-HSCT in mice, and sought to explore its effects on lung immune microenvironment. To construct a BO after allo-HSCT model, bone marrow cells and spleen cells were harvested from C57BL/6 mice. BALB/c mice were lethally irradiated and received 5 × 10 6 bone marrow cells (for BM mice) or 5 × 10 6 bone marrow cells with 10 6 spleen cells (for BO mice) transplantation via tail vein injection. At day 28 post-transplantation, narrowing of the small airway and collagen accumulation within the small airway walls were observed in the BO mice instead of BM mice, as shown by Masson and hematoxylin-eosin staining. Bronchoalveolar lavage fluid (BALF) from the BO mice contained more lymphocytes and neutrophils than the BM mice. Also, autoreactive IgG was observed in bronchial epithelial cells in the BO group only. These data suggests that our model shared similar histological characteristics with BO patients. Alveolar macrophages (AMs) are a major immunocyte subgroup in the lung. The AMs of the BO mice had increased size compared to the BM mice, similar to “foam cells” in atherosclerosis. The number of “form cells” increased by time in the BO group, but was not found in the BM group. A significantly increased the transcription level of CD36 and ABCA1, two key lipid transport genes, was observed in the BO group at day 21, 30, and 45 post-transplantation. Also, mRNA level of M2-like macrophage-related genes like TGF-β1, CD206, Ym1 and Arg1 was upregulated significantly in the BO group compared to the BM group, since day 21 post-transplantation, but not TNF-α, a typical M1-related marker. We next tested could MSC infusion improve the outcomes of BO mice and its influences on the phenotype of AMs. To test this hypothesis, recipients were divided into four groups (BM, BO, MSC1 and MSC2). MSCs were isolated and cultured from femur bone chips of C57BL/6 mice. Mice within the MSC1 group received 10 6 MSCs via tail vein injection at day 7 and day 21 post-transplantation. Mice within the MSC2 group received 10 6 MSCs via tail vein injection at day 21 and day 28 post-transplantation. Mice within the BM or BO group did not receive MSC injection. BALF was harvested at day 14, 35, and 49. The cGVHD symptom score of the MSC1 group reached peak at day 21 post-transplantation and showed a trend of decrease afterwards. On the other hand, although the MSC2 group also showed the same trend, but increased again after day 42. The MSC1 group have significantly lower cGVHD symptom score compared to the BO group at day 35, 42 and 49. Also, the MSC1 group showed a trend of increased survival compared to the BO group. As for AM phenotypes, MSC1 group had a trend of decreased proportion on both M1-like (CD206- CD86+ iNOS+) and M2-like (CD86- CD163+) AMs compared to the BO group at day 14. At day 49, the MSC 1 and MSC2 group both showed a trend of decreased M2-like AMs and regulatory T cells (CD25+ Foxp3+) proportion. Taking together, we found that AMs of BO mice trended a M2-like phenotype. MSC infusion could improve the outcomes of BO mice, and modulate the phenotype of AMs.

Household Air Pollution and Child Lung Function: The Ghana Randomized Air Pollution and Health Study.

Rationale: The impact of a household air pollution (HAP) stove intervention on child lung function has been poorly described. Objectives: To assess the effect of a HAP stove intervention for infants prenatally to age 1 on, and exposure-response associations with, lung function at child age 4. Methods: The Ghana Randomized Air Pollution and Health Study randomized pregnant women to liquefied petroleum gas (LPG), improved biomass, or open-fire (control) stove conditions through child age 1. We quantified HAP exposure by repeated maternal and child personal carbon monoxide (CO) exposure measurements. Children performed oscillometry, an effort-independent lung function measurement, at age 4. We examined associations between Ghana Randomized Air Pollution and Health Study stove assignment and prenatal and infant CO measurements and oscillometry using generalized linear regression models. We used reverse distributed lag models to examine time-varying associations between prenatal CO and oscillometry. Measurements and Main Results: The primary oscillometry measure was reactance at 5 Hz, X5, a measure of elastic and inertial lung properties. Secondary measures included total, large airway, and small airway resistance at 5 Hz, 20 Hz, and the difference in resistance at 5 Hz and 20 Hz (R5, R20, and R5-20, respectively); area of reactance (AX); and resonant frequency. Of the 683 children who attended the lung function visit, 567 (83%) performed acceptable oscillometry. A total of 221, 106, and 240 children were from the LPG, improved biomass, and control arms, respectively. Compared with control, the improved biomass stove condition was associated with lower reactance at 5 Hz (X5 z-score: β = -0.25; 95% confidence interval [CI] = -0.39, -0.11), higher large airway resistance (R20 z-score: β = 0.34; 95% CI = 0.23, 0.44), and higher AX (AX z-score: β = 0.16; 95% CI = 0.06, 0.26), which is suggestive of overall worse lung function. The LPG stove condition was associated with higher X5 (X5 score: β = 0.16; 95% CI = 0.01, 0.31) and lower small airway resistance (R5-20 z-score: β = -0.15; 95% CI = -0.30, 0.0), which is suggestive of better small airway function. Higher average prenatal CO exposure was associated with higher R5 and R20, and distributed lag models identified sensitive windows of exposure between CO and X5, R5, R20, and R5-20. Conclusions: These data support the importance of prenatal HAP exposure on child lung function. Clinical trial registered with www.clinicaltrials.gov (NCT01335490).

Deep learning parametric response mapping from inspiratory chest CT scans: a new approach for small airway disease screening.

Parametric response mapping (PRM) enables the evaluation of small airway disease (SAD) at the voxel level, but requires both inspiratory and expiratory chest CT scans. We hypothesize that deep learning PRM from inspiratory chest CT scans can effectively evaluate SAD in individuals with normal spirometry. We included 537 participants with normal spirometry, a history of smoking or secondhand smoke exposure, and divided them into training, tuning, and test sets. A cascaded generative adversarial network generated expiratory CT from inspiratory CT, followed by a UNet-like network predicting PRM using real inspiratory CT and generated expiratory CT. The performance of the prediction is evaluated using SSIM, RMSE and dice coefficients. Pearson correlation evaluated the correlation between predicted and ground truth PRM. ROC curves evaluated predicted PRMfSAD (the volume percentage of functional small airway disease, fSAD) performance in stratifying SAD. Our method can generate expiratory CT of good quality (SSIM 0.86, RMSE 80.13 HU). The predicted PRM dice coefficients for normal lung, emphysema, and fSAD regions are 0.85, 0.63, and 0.51, respectively. The volume percentages of emphysema and fSAD showed good correlation between predicted and ground truth PRM (|r| were 0.97 and 0.64, respectively, p < 0.05). Predicted PRMfSAD showed good SAD stratification performance with ground truth PRMfSAD at thresholds of 15%, 20% and 25% (AUCs were 0.84, 0.78, and 0.84, respectively, p < 0.001). Our deep learning method generates high-quality PRM using inspiratory chest CT and effectively stratifies SAD in individuals with normal spirometry.

Single Cell Transcriptomics of Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans syndrome (BOS) is a manifestation of pulmonary chronic graft versus host disease (cGVHD), a serious complication of allogeneic stem cell transplantation (ASCT). BOS also occurs following bi-orthotopic lung transplant (BOLT), where it is termed chronic lung allograft dysfunction (CLAD)-BOS and is the leading cause of long-term allograft failure. In both contexts, fibrotic obliteration of the small airways leads to progressive respiratory failure. Since the molecular mechanisms leading to fibrotic airway remodeling in humans are poorly understood, we used single cell RNA-sequencing to map intercellular interactions between immune (CD45+ve) and non-immune (CD45-ve) cells of lung explants from patients undergoing first lung transplantation for cGVHD-BOS (n=1) or second lung transplantation for CLAD-BOS (n=2) compared to normal controls (NC) (n=3). BOS patients ranged in age from 44 to 61 years old; NC were similar in age and died of cerebrovascular accidents. Lungs were surgically removed at the time of BOLT (BOS samples) or at autopsy (NC). CD45+ve and CD45-ve cells were magnetically sorted and freshly processed. Single cell libraries were prepared using the 10X Genomics Chromium Controller and sequenced on an Illumina Novaseq 6000 instrument. Quality control filtering, transcript count normalization, integration, PCA, UMAP projection, and cell clustering were performed with Seurat in R v4.2.1. CD45+ve and CD45-ve cells were annotated in Azimuth using the Human Lung Cell Atlas and LungMAP Cell Cards reference data sets, respectively. Differences in gene expression between conditions were evaluated with the Seurat FindMarkers function. Inter-cellular communications were characterized with CellChat. Interaction strength was calculated as a function of ligand/receptor pair expression, and incoming and outgoing signaling was classified using network centrality analysis. We identified 45,932 CD45+ve cells (28,241 in BOS and 17,691 in NC) and 33,428 CD45-ve cells (23,390 in BOS and 10,038 in NC) including 17 distinct cell types in the CD45+ve fractionand 24 in the CD45-ve fraction. As samples came from patients with end-stage disease, we hypothesized that CD45+ve cells would be highly activated while CD45-ve cells would exhibit strongly fibrogenic programs. To test this hypothesis, we analyzed the incoming and outgoing signal strength for each cell type. Stromal cells such as type 1 (AF1) and type 2 alveolar fibroblasts (AF2), secondary crest myofibroblasts (SCMF), and pericytes had the strongest outgoing signals in BOS ( Figure 1). Except for AF2, incoming and outgoing signaling from stromal cells was stronger in BOS than in NC. These observations support stromal cells as important drivers of BOS pathogenesis. Next, we characterized signaling directionality between stromal cells and CD45+ve cells. In general, incoming signals to stromal cells from CD45+ve cells were weaker in BOS than in NC, while outgoing signals from stromal cells to CD45+ve cells were stronger. For example, signaling from stromal cells expressing THY1, which may attenuate fibrosis in fibrotic lung disease, to integrins on monocytes and macrophages was stronger in BOS. Likewise, BOS was enriched for signaling from collagens and fibronectin on stromal cells to CD44 on CD45+ve cells. As expected, genes implicated in fibrosis and wound healing were upregulated in stromal cells in BOS patients. In AF1 ( Figure 2), these included genes encoding collagens (COL6A3, COL14A1), actins (ACTA2), matricellular proteins (POSTN, TNC, SPARC), protease inhibitors (SERPINE1, TIMP1), hyaluronic acid synthetases (HAS2), proteoglycans (LUM, VCAN), and proteases (MMP19, ADAMTS9). Interestingly, we found evidence for active anti-fibrotic programs such as MMP19, PTGS2, and THY1. To our knowledge, this is the first study employing single cell transcriptomics of lung explants from patients with cGVHD-associated BOS. Robust signaling from stromal cells to CD45+ve cells may support their role in modifying the inflammatory infiltrate in BOS. We identified outgoing, stromal derived signaling associated with fibrotic (collagen and fibronectin) and anti-fibrotic programs (THY1). Our findings illustrate an interplay between pro- and anti-fibrotic programs even in end-stage BOS lungs, raising the tantalizing possibility to intervene therapeutically in this dyshomeostatic balance.

Role of Screening Lung Function Tests in a Routine Health Checkup.

Background and objectives The lung function test is a gold standard, guideline-recommended test to detect obstructive airway diseases like asthma and COPD. It is of considerable value in detecting the presence and severity of airflow obstruction in patients with respiratory symptoms. However, the role of spirometry in a routine health checkup is controversial.Spirometry, when used in routine health checkup settings as a case-finding tool for all adults with persistent respiratory symptoms or having a history of exposure to risk factors, is likely to label a relatively large proportion of individuals as diseased with airflow obstruction. Conversely, spirometry is normal in a relatively large percentage of adults who report respiratory symptoms including dyspnea, the respiratory symptom having the greatest impact on quality of life.The objective of this study is to determine the utility of spirometry as a screening test to detect airflow obstruction in otherwise healthy subjects undergoing a routine health checkup. Methods This observational study was conducted with 538 health checkup individuals aged 18 and over. A brief history was taken prior to the test. Lung function tests were performed and interpreted as per the Global Initiative for Chronic Obstructive Lung Disease criteria. The anthropometric and spirometric data obtained were compared to other population-based spirometric studies to compare the prevalence of airflow limitation, the risk factors, and smoking history. Results Of the total 538 subjects incorporated in the study, 305 (57%) were males and 233 (43%) were females aged between 18 to 80 years with a mean age of 45 years. The male-to-female ratio was 1.3:1 with a mean BMI of 25.9. The overall yield from lung function tests in detecting airflow obstruction was 63 subjects (11.7%), of which 36 (11.8%) were males and 27 (11.5%) were females. Seventy-three subjects (13.5%) were classified as having a small airway obstruction, of which 34 were males (46.6%), and 39 were females (53.4%). The distribution of airflow obstruction by age was with eight subjects (5.4%) in the 18-35 group, 21 subjects (7.8%) in the 36-55 group, and 34 (25%) in the elderly (>55) age group.Although overall smoking history showed no significant association with developing airflow obstruction, significant association with smoking was found in the elderly (>55) age group. Interpretation and conclusions The results of the study suggest that lung function tests should be included in routine health checkups in the subset of individuals greater than 35 years of age with or without a history of smoking, in all age groups with a family history of asthma, in individuals with respiratory symptoms and inindividuals greater than 55 years of age with a moderate history of smoking.

Acute and repeated exposures of normal human bronchial epithelial (NHBE) cells culture to particles from a coloured pyrotechnic smoke

Coloured pyrotechnic smokes are frequently used in the military field and occasionally by civilians, but their health hazards have been little studied. The main concern could rise from inhalation of smoke particles. Our previous study showed that acute exposure to particles from a red signalling smoke (RSS) induced an antioxidant and inflammatory responses in small airway epithelial cells. The aim of this study was to further explore the toxicity of RSS particles at a more proximal level of the respiratory tract, using normal human bronchial epithelial cells grown at the Air-Liquid Interface. Acute exposure (24 h) induced an oxidative stress that persisted 24 h post-exposure, associated with particle internalization and epithelium morphological changes (cuboidal appearance and loss of cilia). Repeated exposures (4×16h) to RSS particles did not trigger oxidative stress but cell morphological changes occurred. Overall, this study provides a better overview of the toxic effects of coloured smoke particles.

Climate Change and New Challenges for Rural Communities: Particulate Matter Matters.

Climate change presents multiple challenges to rural communities. Here, we investigated the toxicological potential of the six types of particulate matter most common to rural Arkansas: soil, road, and agricultural dusts, pollen, traffic exhaust, and particles from biomass burning in human small airway epithelial cells (SAECs). Biomass burning and agricultural dust demonstrated the most potent toxicological responses, exhibited as significant (p < 0.05) up-regulation of HMOX1 (oxidative stress) and TNFα (inflammatory response) genes as well as epigenetic alterations (altered expression of DNA methyltransferases DNMT1, DNMT3A, and DNMT3B, enzymatic activity, and DNA methylation of alpha satellite elements) that were evident at both 24 h and 72 h of exposure. We further demonstrate evidence of aridification in the state of Arkansas and the presence of winds capable of transporting agricultural dust- and biomass burning-associated particles far beyond their origination. Partnerships in the form of citizen science projects may provide important solutions to prevent and mitigate the negative effects of the rapidly evolving climate and improve the well-being of rural communities. Furthermore, the identification of the most toxic types of particulate matter could inform local policies related to agriculture, biomass burning, and dust control.

The Role of Small Airway Disease in Pulmonary Fibrotic Diseases.

Small airway disease (SAD) is a pathological condition that affects the bronchioles and non-cartilaginous airways 2 mm or less in diameter. These airways play a crucial role in respiratory function and are often implicated in various pulmonary disorders. Pulmonary fibrotic diseases are characterized by the thickening and scarring of lung tissue, leading to progressive respiratory failure. We aimed to present the link between SAD and fibrotic lung conditions. The evidence suggests that SAD may act as a precursor or exacerbating factor in the progression of fibrotic diseases. Patients with fibrotic conditions often exhibit signs of small airway dysfunction, which can contribute to worsening respiratory symptoms and decreased lung function. Moreover, individuals with advanced SAD are at a heightened risk of developing fibrotic changes in the lung. The interplay between inflammation, environmental factors, and genetic predisposition further complicates this association. The early detection and management of SAD can potentially mitigate the progression of fibrotic diseases, highlighting the need for comprehensive clinical evaluation and research. This review emphasizes the need to understand the evolving connection between SAD and pulmonary fibrosis, urging further detailed research to clarify the causes and potential treatment between the two entities.

Loss of p73 Expression Contributes to Chronic Obstructive Pulmonary Disease.

Rationale: Multiciliated cell (MCC) loss and/or dysfunction is common in the small airways of patients with chronic obstructive pulmonary disease (COPD), but it is unclear if this contributes to COPD lung pathology. Objectives: To determine if loss of p73 causes a COPD-like phenotype in mice and explore whether smoking or COPD impact p73 expression. Methods: p73floxE7-E9 mice were crossed with Shh-Cre mice to generate mice lacking MCCs in the airway epithelium. The resulting p73Δairway mice were analyzed using electron microscopy, flow cytometry, morphometry, forced oscillation technique, and single-cell RNA sequencing. Furthermore, the effects of cigarette smoke on p73 transcript and protein expression were examined using invitro and invivo models and in studies including airway epithelium from smokers and patients with COPD. Measurements and Main Results: Loss of functional p73 in the respiratory epithelium resulted in a near-complete absence of MCCs in p73Δairway mice. In adulthood, these mice spontaneously developed neutrophilic inflammation and emphysema-like lung remodeling and had progressive loss of secretory cells. Exposure of normal airway epithelium cells to cigarette smoke rapidly and durably suppressed p73 expression invitro and invivo. Furthermore, tumor protein 73 mRNA expression was reduced in the airways of current smokers (n = 82) compared with former smokers (n = 69), and p73-expressing MCCs were reduced in the small airways of patients with COPD (n = 11) compared with control subjects without COPD (n = 12). Conclusions: Loss of functional p73 in murine airway epithelium results in the absence of MCCs and promotes COPD-like lung pathology. In smokers and patients with COPD, loss of p73 may contribute to MCC loss or dysfunction.

Transcriptome analysis reveals the impact of NETs activation on airway epithelial cell EMT and inflammation in bronchiolitis obliterans

Bronchiolitis obliterans (BO) is a chronic airway disease that was often indicated by the pathological presentation of narrowed and irreversible airways. However, the molecular mechanisms of BO pathogenesis remain unknown. Although neutrophil extracellular traps (NETs) can contribute to inflammatory disorders, their involvement in BO is unclear. This study aims to identify potential signaling pathways in BO by exploring the correlations between NETs and BO. GSE52761 and GSE137169 datasets were downloaded from gene expression omnibus (GEO) database. A series of bioinformatics analyses such as differential expression analysis, gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG), and gene set enrichment analysis (GSEA) were performed on GSE52761 and GSE137169 datasets to identify BO potential signaling pathways. Two different types of BO mouse models were constructed to verify NETs involvements in BO. Additional experiments and bioinformatics analysis using human small airway epithelial cells (SAECs) were also performed to further elucidate differential genes enrichment with their respective signaling pathways in BO. Our study identified 115 differentially expressed genes (DEGs) that were found up-regulated in BO. Pathway enrichment analysis revealed that these genes were primarily involved in inflammatory signaling processes. Besides, we found that neutrophil extracellular traps (NETs) were formed and activated during BO. Our western blot analysis on lung tissue from BO mice further confirmed NETs activation in BO, where neutrophil elastase (NE) and myeloperoxidase (MPO) expression were found significantly elevated. Transcriptomic and bioinformatics analysis of NETs treated-SAECs also revealed that NETs-DEGs were primarily associated through inflammatory and epithelial-to-mesenchymal transition (EMT) -related pathways. Our study provides novel clues towards the understanding of BO pathogenesis, in which NETs contribute to BO pathogenesis through the activation of inflammatory and EMT associated pathways. The completion of our study will provide the basis for potential novel therapeutic targets in BO treatment.

Spirometry in the diagnosis of cough variant asthma in children.

This study aimed to assess the diagnostic utility of spirometry, particularly focusing on small airway parameters, in children with cough variant asthma (CVA). This study included children aged 5-12 years with a diagnosis of CVA. Pre- and postbronchodilation spirometry parameters, including FEV1 %pred, FVC%pred, FEV1 /FVC%pred, PEF%pred, FEF25 %pred, FEF50 %pred, FEF75 %pred, MMEF%pred, were recorded. Receiver operating characteristic curves were plotted, and the area under the curve (AUC) was calculated to assess the discriminatory potential of these spirometry parameters for CVA. A prediction model based on logistic regression (LR) was performed. A total of 200 patients with CVA and 73 control subjects were included. Baseline spirometry parameters in the CVA group, except for FVC%pred, were significantly lower compared to the control group. After inhalation of salbutamol sulfate, all parameters showed significant improvement in the CVA group. However, these parameters, except for FEV1 %pred and FVC%pred, remained lower in the CVA group compared to the control group. The improvement rate of each parameter in the CVA group, except for ∆ FVC%, was significantly higher than that in the control group. △ MMEF% achieved the highest AUC of 0.797 with a threshold value of 16.09%, followed by △ FEF75 % (0.792), △ FEV1 % (0.756), and △ FEF50 % (0.747) with threshold values of 19.01%, 4.48%, and 19.4%, respectively. The clinical prediction model included four variables (age, △ FEF25 %, △ FEF75 %, and △ MMEF%) and demonstrated excellent performance distinguishing patients with and without CVA (AUC = 0.850). In the CVA group, the △ FEV1 % showed a positive correlation with small airway parameters. This study highlights that children with CVA exhibit lower pulmonary function parameters compared to healthy children. Changes in small airway parameters during bronchodilator tests can be valuable in diagnosing CVA, and the LR prediction model incorporating age and several pulmonary parameters can assist physicians in accurately identifying CVA in clinical practice.

The Effect of Ferritin Level on Respiratory Functions in Patients with β-Thalassemia Major

Introduction-Purpose β-thalassemia major (β-TM) is an autosomal recessive disorder caused by mutations in the β-globin gene of hemoglobin. The disease is characterized by splenomegaly due to ineffective erythropoiesis, iron accumulation signs in tissues as a result of increased iron absorption, bone expansion due to increased erythropoietic activity, and decreased tissue oxygenation. One of the effected organ can be the lungs due to excessive iron deposition in these patients. The current study aimed to investigate the effect of serum ferritin level, which is known as a marker of iron accumulation in tissues, on pulmonary function tests (PFT) in patients with β-TM. Methods and Materials Patients aged ≥6 years who were regularly followed in the pediatric hematology section of Mersin City Research and Training Hospital with a diagnosis of β-TM were included. All patients received regular blood transfusion and iron chelation therapy. Study participants underwent PFT prior to blood transfusion in the pediatric pulmonology section Results A total of 43 patients with β-TM were studied. Included patients were divided into two groups according to the mean annual ferritin level; low ferritin group if below 2000 ml/ng and high ferritin group if above 2000 ml/ng. The low ferritin group was consisted of 19 patients and the high ferritin group was consisted of 24 patients. The characteristics of these two groups are shown in Table 1. There were no statistical significance in age, gender, body mass index, age at diagnosis, mean annual hemoglobin, splenectomy, cardiac involvement and oxygen saturation among both groups, but the number of annual transfusion was significantly higher in the high ferritin group than lower ferritin group. When PFT parameters of both groups were compared, FVC (forced vital capacity) was statistically lower in the high ferritin group compared to the low ferritin group. Other parameters included FEV 1 (forced expiratory volume in 1 second), FEV 1/FVC ratio, PEF (peak expiratory flow) and FEF 25-75 (forced expiratory flow between 25% and 75% of vital capacity) were similar among groups. (Table 2) Discussion Patients with β-TM may accumulate iron in the interstitial area of the lungs which can lead fibrosis and impaired lung function over time. There are several studies investigated lung dysfunction and its etiology in these patients. Although the results of the studies are varied, the majority of them reported a restrictive pattern of respiratory dysfunction in thalassemia patients. Additionally, some studies showed the presence of mild or moderate obstruction in small airways and decrease in diffusion capacity with the increase of alveolar-capillary membrane thickness at advanced ages. In the present study, we found that patients with β-TM who had high ferritin level showed restrictive type lung function compared to those with low ferritin level. There were no difference among the groups in obstructive parameters (i.e. FEV 1, FEV 1/FVC, FEF 25-75) of PFT. In the literature, studies investigating PFT in patients with high ferritin levels had variable results, impaired or no change, in pulmonary status. In conclusion, loss of respiratory function and impaired tissue oxygenation in patients with β-TM may develop over time due to iron deposition in the interstitial area. PFT assessment of these patients is essential and recommended for the detection of early lung disease. Routine PFT follow in patients with β-TM of high ferritin values is highly important.