Role of air pollutants in airway epithelial barrier dysfunction in asthma and COPD

Impact of PM2.5, relative humidity, and temperature on sleep quality: a cross-sectional study in Taipei

INTRODUCTION

TWe investigated impacts of particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5), relative humidity (RH), and temperature on sleep stages and arousal.

MATERIALS AND METHODS

A cross-sectional analysis involving 8,611 participants was conducted at a sleep center in Taipei. We estimated individual-level exposure to RH, temperature, and PM2.5 over 1-day, 7-day, and 30-day periods. Linear regression models assessed the relationship between these environmental factors and sleep parameters across different seasons. Mediation analysis was used to explore PM2.5, RH, and temperature roles in these relationships.

RESULTS

A 1% increase in RH over 1 and 7 days was associated with changes in non-rapid eye movement (NREM) sleep stages and increases in the arousal index across all seasons. A 1°C increase in temperature over similar periods led to increases in rapid eye movement (REM) sleep. During cold season, changes in RH and temperature were linked to variations in arousal and NREM sleep stages. In hot season, RH and temperature increases were correlated with changes in NREM sleep stages and arousal. Across all groups, a 1-μg/m³ increase in PM2.5 levels was associated with alterations in NREM and REM sleep stages and increases in the arousal index. We found PM2.5 levels mediated relationships between RH, temperature, and various sleep stages, particularly in cold season.

CONCLUSIONS

Lower RH and temperature, contributing to deep sleep reduction and increased arousal, were influenced by elevated PM2.5 exposure, especially during colder months. Enhancing environmental quality and reducing PM2.5 levels may lead to improved sleep quality.

Glutathione Attenuates Diesel Exhaust-Induced Lung Epithelial Injury via NF-κB/Nrf2/GPX4-Mediated Ferroptosis

Diesel exhaust (DE) emissions pose a significant threat to public health. This study linked DE-mediated reactive oxygen species (ROS) and ferroptosis with lung epithelial disruption, also the protective potential of exogenous glutathione (GSH) administration was investigated. C57BL/6 mice were divided into three groups: filtered air (control), DE exposed, and DE+GSH (administered intranasally on alternate days). Airway hyperresponsiveness (AHR), lung tissues, and bronchoalveolar lavage fluid (BALF) were used for analysis. DE exposure significantly impaired lung function parameters as shown by AHR. Elevated ROS depleted the GSH/GSSG ratio and suppressed Nrf2 activity, disrupting antioxidant defense mechanisms, which were restored by GSH administration. DE-induced ROS acted as a key driver of ferroptosis, characterized by suppressed SLC7411 expression thereby decreased GSH synthesis and GPX-4 activity, inducing lipid peroxidation. Ferroptosis was significantly mitigated by increased GSH pool, which restored GPX-4 levels and reduced lipid peroxidation. Concurrently, DE induced ROS promoted DNA damage and apoptosis in lung epithelial cells wherein GSH treatment preserved cell survival in DE exposed mice. The heightened DE-associated ROS further amplified inflammation, as shown by increased cytokines (TNF-α, IL-6, TSLP, IL-33) and P-NF-κB activation. Activated inflammatory cascade disrupted tight junction proteins (claudins, occludin), resulted in weakened epithelial barrier and increased permeability. Lung barrier disruption was evidenced by transmission electron microscopy and immunohistochemistry, corroborated with elevated albumin levels. GSH effectively restored tight junction integrity and preserved barrier function in DE+GSH mice lungs. In conclusion, DE-induced oxidative stress and ferroptosis-triggered inflammation compromised epithelial barrier promoting lung injury. Exogenous GSH administration showed potential in restoring DE-associated lung damage.

Life-threatening risk factors contribute to the development of diseases with the highest mortality through the induction of regulated necrotic cell death

Chronic diseases affecting the cardiovascular system, diabetes mellitus, neurodegenerative diseases, and various other organ-specific conditions, involve different underlying pathological processes. However, they share common risk factors that contribute to the development and progression of these diseases, including air pollution, hypertension, obesity, high cholesterol levels, smoking and alcoholism. In this review, we aim to explore the connection between four types of diseases with different etiologies and various risk factors. We highlight that the presence of risk factors induces regulated necrotic cell death, leading to the release of damage-associated molecular patterns (DAMPs), ultimately resulting in sterile inflammation. Therefore, DAMP-mediated inflammation may be the link explaining how risk factors can lead to the development and maintenance of chronic diseases. To explore these processes, we summarize the main cell death pathways activated by the most common life-threatening risk factors, the types of released DAMPs and how these events are associated with the pathophysiology of diseases with the highest mortality. Various risk factors, such as smoking, air pollution, alcoholism, hypertension, obesity, and high cholesterol levels induce regulated necrosis. Subsequently, the release of DAMPs leads to chronic inflammation, which increases the risk of many diseases, including those with the highest mortality rates.

Effects of acute PM2.5 purification on cognitive function and underlying mechanisms: Evidence from integrating alternative splicing into multi-omics

The relationship between fine particulate matter (PM2.5) and cognition has been extensively investigated. However, the causal impact of acute PM2.5 purification on cognition improvement and the underlying biological mechanisms remain relatively opaque. Our double-blinded randomized controlled trial assessed the impact of acute PM2.5 purification on executive function, underpinned by multi-omics approaches including alternative splicing (AS) analysis. A total of 93 participants experienced a two-hour exposure to either reduced and normal PM2.5 levels. We measured the cognition of healthy young adults, collected peripheral blood before and after intervention, and performed multi-omics analysis including transcriptomics, metabolomics, and proteomics. Results indicated that reducing PM2.5 by 1 μg/m3 was associated with a 0.10 % (95 % CI: [0.18 %, 0.01 %]; p = 0.031) improvement in executive function. Notably, we identified 96 AS events without concurrent transcriptional amount alterations. Multi-layered omics analyses revealed disrupted pathways in hypoxia, mitochondrial function and energy metabolism, and immune responses, validated by ELISA and biochemical assay. These findings demonstrated short-term improvements of cognition following PM2.5 purification and provide mechanistic understandings of PM2.5-induced cognition alterations. This study underscores the significance of incorporating AS in the molecular framework of multi-omics research by exploring variable exon splicing, which could enrich multi-omics analysis methodologies and expose to broader audience.

Targeting respiratory virus-induced reactive oxygen species in airways diseases

The immune response to virus infection in the respiratory tract must be carefully balanced to achieve pathogen clearance without excessive immunopathology. For chronic respiratory diseases where there is ongoing inflammation, such as in asthma and COPD, airway immune balance is perturbed, and viral infection frequently worsens (exacerbates) these conditions. Reactive oxygen species (ROS) are critical to the induction and propagation of inflammation, and when appropriately regulated, ROS are vital cell signalling molecules and contribute to innate immunity. However, extended periods of high ROS concentration can cause excessive cellular damage that dysregulates antiviral immunity and promotes inflammation. Traditional antioxidant therapeutics have had limited success treating inflammatory diseases such as viral exacerbations of asthma or COPD, owing to nonspecific pharmacology and poorly understood pharmacokinetic properties. These drawbacks could be addressed with novel drug delivery technologies and pharmacological agents. This review summarises current research on ROS imbalances during virus infection, discusses the commercially available mitochondrial antioxidant drugs that have progressed to clinical trial and assesses novel drug delivery approaches for antioxidant delivery to the airways. Additionally, it provides a perspective on future research into pharmacological targeting of ROS for the treatment of respiratory virus infection and disease.

Association Between Urinary Glyphosate Concentrations and Chronic Obstructive Pulmonary Disease in USA Participants: Evidence from NHANES 2013-2018

Background

Glyphosate has raised health concerns due to its widespread detection in environment and human tissues. Limited evidence exists found in the association between urinary glyphosate concentrations and chronic obstructive pulmonary disease.

Methods

Analyzing data from 2588 participants, we applied survey-weighted logistic regression models and cubic spline techniques to quantify link between urinary glyphosate concentrations and prevalence of COPD. Further subgroup and sensitivity analyses were also conducted.

Results

Study revealed a significant association between higher urinary glyphosate concentrations that increased risk of COPD. In fully adjusted models, a one-unit increase in natural logarithm of urinary glyphosate was associated with a 35% increased risk of COPD (OR, 1.35, 95% CI, 1.01-1.82, P=0.043). Subgroup analyses showed consistent associations across different demographic groups with a pronounced association in current smokers and females. Sensitivity analyses and exclusion of participants with chronic kidney disease reinforced the robustness of the findings.

Conclusion

Findings provide evidence of a positive association between urinary glyphosate concentrations and prevalence of COPD in a representative sample of the adult population at the United States of America. Further studies are needed to investigate the influence of factors and other environmental pollutants on COPD.

Airway epithelial cells as drivers of severe asthma pathogenesis

Our understanding of the airway epithelium's role in driving asthma pathogenesis has evolved over time. From being regarded primarily as a physical barrier that could be damaged via inflammation, the epithelium is now known to actively contribute to asthma development through interactions with the immune system. The airway epithelium contains multiple cell types with specialized functions spanning barrier action, mucociliary clearance, immune cell recruitment, and maintenance of tissue homeostasis. Environmental insults may cause direct or indirect injury to the epithelium leading to impaired barrier function, epithelial remodelling, and increased release of inflammatory mediators. In severe asthma, the epithelial barrier repair process is inhibited and the response to insults is exaggerated, driving downstream inflammation. Genetic and epigenetic mechanisms also maintain dysregulation of the epithelial barrier, adding to disease chronicity. Here, we review the role of the airway epithelium in severe asthma and how targeting the epithelium can contribute to asthma treatment.

Short-lived reactive components substantially contribute to particulate matter oxidative potential

Exposure to airborne particulate matter (PM) has been attributed to millions of deaths annually. However, the PM components responsible for observed health effects remain unclear. Oxidative potential (OP) has gained increasing attention as a key property that may explain PM toxicity. Using online measurement methods that impinge particles for OP quantification within seconds, we reveal that 60 to 99% of reactive oxygen species (ROS) and OP in secondary organic aerosol and combustion-generated PM have a lifetime of minutes to hours and that the ROS activity of ambient PM decays substantially before offline analysis. This implies that current offline measurement methods substantially underestimate the true OP of PM. We demonstrate that short-lived OP components activate different toxicity pathways upon direct deposition onto reconstituted human bronchial epithelia. Therefore, we suggest that future air pollution and health studies should include online OP quantification, allowing more accurate assessments of links between OP and health effects.

The association between body mass index and asthma in children: a cross‑sectional study from NHANES 1999 to 2020

The relationship between body mass index (BMI) and the risk of asthma in the pediatric population is not fully understood. This study aimed to investigate the association between BMI and asthma in a large nationally representative sample. The study included 35,603 pediatric participants from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2020. The association between BMI and asthma was examined using various statistical models, including logistic regression, piece-wise linear regression, and subgroup analyses, adjusting for potential confounding factors. When analyzing BMI as a continuous variable, a one-unit increase in BMI was associated with a 4% higher odds of asthma. A clear dose-response relationship was observed, where individuals in the higher BMI quartiles had progressively higher odds of asthma compared to those in the lowest quartile. Smooth curve fitting revealed a not entirely linear relationship, with a steeper increase in asthma risk at lower BMIs (below an inflection point of 21 kg/m²) compared to higher BMIs. Subgroup analyses consistently showed a positive association between BMI and asthma across different age, gender, race, socioeconomic, and smoking-related factors. Sensitivity analyses, including multiple imputation for missing data and alternative BMI metrics, confirmed the stability of the results. This study provides robust evidence for a positive and not entirely linear association between BMI and the risk of asthma in the pediatric population. These findings enhance the existing literature and underscore the necessity of considering BMI in both asthma research and clinical practice.

Urban air pollution and chronic respiratory diseases in adults: insights from a cross-sectional study

Objectives

Air pollution poses a substantial public health risk, especially in urban environments characterized by elevated levels of pollutants such as fine particulate matter (PM2.5) and nitrogen dioxide (NO2). These pollutants negatively impact respiratory health, contributing to chronic respiratory conditions and reduced lung function. This study investigated the association between air pollution exposure and respiratory health outcomes, including the prevalence of chronic respiratory conditions and pulmonary function, in an urban population. Additionally, the study sought to identify demographic subgroups that are unprotected from the ill effects of air pollution.

Methods

A cross-sectional study included a total of 1,300 adult participants recruited from outpatient pulmonary and general medicine clinics. Air pollution exposure was assessed based on residential proximity to major traffic routes and ambient levels of PM2.5 and NO2 obtained from the Riyadh air quality monitoring network. Lung function was measured using spirometry, and data on chronic respiratory conditions were collected through self-reports and medical record reviews. Multivariable logistic regression and linear regression models were used to analyze the association between air pollution exposure and respiratory outcomes, adjusting for confounders such as age, gender, smoking Status, socioeconomic Status, physical activity, and occupational exposures.

Results

Higher air pollution level exposures were significantly associated with an increased prevalence of chronic respiratory conditions (adjusted OR for high exposure: 2.45, 95% CI: 1.70-3.55, p < 0.001) and a reduction in lung function, as indicated by declines in FEV1 and FVC (adjusted FEV1 coefficient for high exposure: -0.45, 95% CI: -0.58 to -0.32, p < 0.001). Subgroup analyses revealed that older adults, males, and current smokers were particularly susceptible to the adverse effects of air pollution. Sensitivity analyses confirmed the robustness of these findings across different analytical scenarios.

Conclusion

The study demonstrated a clear and significant association between higher air pollution level exposures and an increased risk of chronic respiratory conditions and reduced lung function. These findings highlight the need for specific interventions to decrease air pollution exposure, particularly in vulnerable urban populations, to mitigate the burden of respiratory diseases.

Evaluating the health impact of air pollution control strategies and synergies among PM2.5 and O3 pollution in Beijing-Tianjin-Hebei region, China

Since 2013, China has implemented a series of strict Air Pollution Control Strategies (APCS) to mitigate environmental and health risks associated with ambient fine particulate matter (PM2.5). However, while APCS sets clear targets for PM2.5 concentration, it lacks quantitative control over O3 levels. Most existing studies have focused on nation-wide health assessments. Therefore, by conducting a coupled framework using health assessment and decomposition method, the spatiotemporal variation in deaths attributable to PM2.5 pollution, as well as the role of APCS and the synergies between PM2.5 and O3 on PM2.5 concentration and health impacts in the Beijing-Tianjin-Hebei (BTH) region have been explored. The result showed that: (1) PM2.5 concentration in the BTH region decreased by 68.2%, with a reduction of 45,833 (95% Confidence Interval [CI]: 33,808, 50,069) deaths over the period. However, both concentrations and mortality remained high, indicating a need for faster reductions. (2) End-of-pipe control contributed the most to reducing PM2.5 concentrations and deaths, though the gaps between source control and end-of-pipe control is narrowing. (3) The synergistic effects of O3 and PM2.5 in reducing concentration and mortality have increased, becoming a significant driver of PM2.5-related health impacts. Our study emphasizes the future importance of implementing refined, diverse emission reduction measures and coordinating efforts to reduce both O3 and PM2.5 emissions, which are crucial for achieving the Sustainable Development Goals (SDGs) and advancing the "Beautiful China" and "Healthy China" initiatives.

Role of E-cadherin in epithelial barrier dysfunction: implications for bacterial infection, inflammation, and disease pathogenesis

Epithelial barriers serve as critical defense lines against microbial infiltration and maintain tissue homeostasis. E-cadherin, an essential component of adherens junctions, has emerged as a pivotal molecule that secures epithelial homeostasis. Lately, its pleiotropic role beyond barrier function, including its involvement in immune responses, has become more evident. Herein, we delve into the intricate relationship between (dys)regulation of epithelial homeostasis and the versatile functionality of E-cadherin, describing complex mechanisms that underlie barrier integrity and disruption in disease pathogenesis such as bacterial infection and inflammation, among others. Clinical implications of E-cadherin perturbations in host pathophysiology are emphasized; downregulation, proteolytic phenomena, abnormal localization/signaling and aberrant immune reactions are linked with a broad spectrum of pathology beyond infectious diseases. Finally, potential therapeutic interventions that may harness E-cadherin to mitigate barrier-associated tissue damage are explored. Overall, this review highlights the crucial role of E-cadherin in systemic health, offering insights that could pave the way for strategies to reinforce/restore barrier integrity and treat related diseases.

Development and validation of a novel AI-derived index for predicting COPD medical costs in clinical practice

Background

Chronic Obstructive Pulmonary Disease (COPD) is a major contributor to global morbidity and healthcare costs. Accurately predicting these costs is crucial for resource allocation and patient care. This study developed and validated an AI-driven COPD Medical Cost Prediction Index (MCPI) to forecast healthcare expenses in COPD patients.

Methods

A retrospective analysis of 396 COPD patients was conducted, utilizing clinical, demographic, and comorbidity data. Missing data were addressed through advanced imputation techniques to minimize bias. The final predictors included interactions such as Age × BMI, alongside Tumor Presence, Number of Comorbidities, Acute Exacerbation frequency, and the DOSE Index. A Gradient Boosting model was constructed, optimized with Recursive Feature Elimination (RFE), and evaluated using 5-fold cross-validation on an 80/20 train-test split. Model performance was assessed with Mean Squared Error (MSE), Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), and R-squared (R²).

Results

On the training set, the model achieved an MSE of 0.049, MAE of 0.159, MAPE of 3.41 %, and R² of 0.703. On the test set, performance metrics included an MSE of 0.122, MAE of 0.258, MAPE of 5.49 %, and R² of 0.365. Tumor Presence, Age, and BMI were identified as key predictors of cost variability.

Conclusions

The MCPI demonstrates strong potential for predicting healthcare costs in COPD patients and enables targeted interventions for high-risk individuals. Future research should focus on validation with multicenter datasets and the inclusion of additional socioeconomic variables to enhance model generalizability and precision.

Immunological Insights and Therapeutic Advances in COPD: Exploring Oral Bacterial Vaccines for Immune Modulation and Clinical Improvement

Chronic obstructive pulmonary disease (COPD) is a prevalent chronic condition associated with substantial global morbidity and mortality. Primarily caused by prolonged exposure to harmful agents such as dust and gases, COPD is characterized by persistent airflow limitation, clinically manifesting as chronic cough, sputum production, and dyspnea. The disease course alternates between stable phases and exacerbations, with the latter often associated with pathogenic colonization of the respiratory tract. This review examines the immunological underpinnings of COPD, emphasizing the interplay between innate and adaptive immunity in disease pathogenesis. Dysregulated immune responses to environmental factors perpetuate chronic inflammation, resulting in progressive pulmonary epithelial damage and connective tissue hyperplasia, which compromise gas exchange. Exacerbations further exacerbate respiratory failure, aggravating patient symptoms and accelerating disease progression. Despite advances in COPD management, effective therapeutic options remain limited. Current treatments primarily aim to alleviate symptoms, reduce immune activation, and manage infections, yet many patients experience suboptimal outcomes. This review highlights the potential of novel therapeutic approaches targeting immune system cells and pathways. In particular, it explores the promise of oral bacterial vaccines as immunomodulatory agents to enhance immune responses and improve clinical outcomes in COPD, addressing critical gaps in current treatment paradigms.

The different response of PM2.5 stimulated nasal epithelial spheroids in control, asthma and COPD groups

BACKGROUND

Pathobiology of asthma and chronic obstructive pulmonary disease (COPD) is associated with changes among respiratory epithelium structure and function. Increased levels of PM2.5 from urban particulate matter (UPM) are correlated with enlarged rate of asthma and COPD morbidity as well as acute disease exacerbation. It has been suggested that pre-existing pulmonary obstructive diseases predispose epithelium for different biological response than in healthy airways. The aim of this study was to assess the impact of PM2.5 on the biological response of healthy as well as asthma and COPD respiratory epithelium using 3D/spheroid culture model.

METHODS

The spheroids from 5 healthy controls, 8 asthma patients, and 8 COPD patients were exposed to 100 µg/ml of PM2.5 for 24 h.

RESULTS

The common pattern for healthy asthma and COPD epithelium inflammatory response to PM2.5 stimulation include the increase in IL-1β, IL-6, IL-8 mRNA expression, and secretion of IL-6. Asthmatic spheroids produced higher amount of TNF-α and IL-8, whereas COPD spheroids expressed increased mRNA level of MUC5AC and decreased level of MMP7. PM2.5 treatment induced changes in AHR and TLR4 expression on secretory epithelium in COPD.

CONCLUSION

The response of airway epithelium to air pollution is different in healthy people than in obstructive lung disease patients. The impairment of airway epithelium in asthma and COPD changes their response to toxic environmental stimuli. This physiological dysfunction might be associated with diseases exacerbation of obstructive lung diseases.

Activation of ERK/NF-kB Pathways Contributes to the Inflammatory Response in Epithelial Cells and Macrophages Following Manganese Exposure

Different types of metals, including manganese (Mn), are constantly encountered in various environmental matrices due to natural and anthropogenic activities. They induce a sustained inflammatory response in various organs, which is considered to be an important priming event in the pathogenesis of several diseases. Mn-induced neuroinflammation and subsequent neurodegeneration are well recognized. However, emerging data suggest that occupationally and environmentally relevant levels may affect various organs, including the lungs. Therefore, the present study was carried out to investigate the effects of Mn (as Mn2+) exposure on the inflammatory response in human normal bronchial (BEAS-2B) and adenocarcinoma alveolar basal (A549) epithelial cells, as well as in murine macrophages (J774). Mn2+ exposure significantly induced mRNA and protein expression of various pro-inflammatory mediators (cytokines and chemokines) in all cells compared to corresponding vehicle controls. Furthermore, Mn2+ treatment also led to increased phosphorylation of extracellular-signal-regulated kinase (ERK)1/2 and nuclear factor-kappa B (NF-kB) p65 in both epithelial cells and macrophages. As expected, cells treated with inhibitors of ERK1/2 (PD98059) and NF-kB p65 (IMD0354) effectively mitigated the expression of various pro-inflammatory mediators induced by Mn2+, suggesting that ERK/NF-kB pathways have a critical role in the Mn2+-induced inflammatory response. Further, in vivo studies are required to confirm these in vitro findings to support clinical translation.

Association of short-term exposure to ambient air pollution and temperature with bronchiectasis mortality: a nationwide time-stratified case-crossover study

BACKGROUND

Ambient pollution and non-optimal temperature are major risk factors for respiratory health. However, the relationships between short-term exposure to these factors and bronchiectasis mortality remain unknown.

METHODS

A nationwide, time-stratified case-crossover study across Mainland China was conducted from 2013 to 2019. Records of bronchiectasis deaths were extracted from the National Death Registration Reporting Information System. Daily concentrations of fine particulate matter (PM2.5), coarse particulate matter (PM2.5-10), nitrogen dioxide (NO2), ozone (O3), and daily temperature were obtained from high-resolution prediction models. We utilized conditional logistic regression model and distributed lag nonlinear model to explore the associations of these exposures with bronchiectasis mortality.

FINDINGS

We included a total of 19,320 bronchiectasis deaths. Air pollutant was associated with bronchiectasis mortality within the first 3 days after exposure and the exposure-response relationships were almost linear. An interquartile range increase in PM2.5, PM2.5-10, and O3 was associated with increments of 3.18%, 4.14%, and 4.36% in bronchiectasis mortality at lag 02 d, respectively. Additionally, lower temperature was associated with higher odds of bronchiectasis mortality. Compared to referent temperature (23.6 °C), the odds ratio for bronchiectasis mortality associated with extremely low temperature (P1: -13.4 °C) was 1.54 (95% CI: 1.05, 2.25).

INTERPRETATION

This national study provides compelling evidence, and highlights the necessity and importance of reducing air pollution exposures and keeping warm for susceptible populations.

FUNDING

National Natural Science Foundation of China (81925001; 82330070); Innovation Program of Shanghai Municipal Education Commission (202101070007-E00097); Program of Shanghai Municipal Science and Technology Commission (21DZ2201800); Program of Shanghai Shenkang Development Center (SHDC12023110); and Major Project of National Health Commission of China.

Household fuel use and severe asthma symptoms among preschool children in Gauteng province, South Africa: a cross-sectional study

Background

Household air pollution continues to be a major public health hazard due to the continued use of household fuel sources. Globally, approximately 4 million people die prematurely each year due to exposure to household air pollution sources. Children are more susceptible to health effects associated with air pollution because their immune systems and lungs are not fully developed.

Objective

The objective of the study was to investigate the association between household fuel use and current severe asthma symptoms among preschool children in Gauteng province, South Africa.

Methods

This was a cross-sectional study conducted in the City of Tshwane Metropolitan Municipality in Gauteng province, South Africa. A total of 1844 parents and guardians of preschool children completed the modified International Study of Asthma and Allergies in Childhood questionnaire. However, a total of four questionnaires were discarded due to incorrect completion. Therefore, a total of 1840 questionnaires were included in the data analysis. Data were analysed using multiple logistic regression analysis.

Results

The prevalence of current severe asthma symptoms was 15.4%. The use of gas for cooking or heating significantly increased the likelihood of current severe asthma symptoms among preschool children (OR=3.20;95% CI 2.08 to 4.91; p<0.001). The use of open fire sources (paraffin, wood or coal) increased the likelihood of severe asthma symptoms among preschool children by 87% (95% CI 0.98 to 3.55; p=0.057).

Conclusion

The study observed that using gas and open fire sources for cooking or heating was associated with current severe asthma symptoms among preschool children in Gauteng, South Africa. Household air quality regulations should be developed to mitigate child exposure to household air pollution in the study setting.

Occupational Exposure to Charcoal Smoke and Dust, a Major Risk Factor for COPD: A Multiregional Cross-Sectional Study in the Democratic Republic of Congo

BACKGROUND

Occupational exposure to charcoal smoke and dust is a threat to workers' respiratory systems.

RESEARCH QUESTION

What is the prevalence of COPD in charcoal workers compared with that of farmers in rural areas of Democratic Republic of Congo (DRC)?

STUDY DESIGN AND METHODS

This cross-sectional, comparative, and multisite study was performed in the charcoal-producing provinces of southwestern DRC. We randomly included charcoal workers and compared them with farmers (age range, 18-70 years). Air quality indexes, anthropometric features, physical activity, sociodemographic characteristics, and related medical events data were recorded. A lung function questionnaire was used to assess respiratory symptoms and spirometry was performed. COPD was defined as the presence of respiratory symptoms for > 3 months with an FEV1 to FVC ratio less than the lower limit of normal. The prevalence of COPD was calculated, and logistic regression was used to identify COPD-associated factors.

RESULTS

We included 485 participants between August 2020 and July 2021. Charcoal producers (CPs; n = 229) were compared with farmers (n = 118), and charcoal saleswomen (n = 72) were compared with vegetable saleswomen (n = 66). Respective groups were similar in age, job seniority, height, and weight. The air was more polluted at charcoal workplaces. The prevalence of COPD was higher in CPs than in farmers (39.7% vs 14.4%; P < .0001) and higher in charcoal saleswomens compared with vegetable saleswomen (40.3% vs 13.6%; P < .0001). Being a charcoal worker was associated independently with COPD in the CP and farmers groups (adjusted OR, 3.54; 95% CI, 1.94-6.46) and in the saleswomen group (adjusted OR, 7.85; 95% CI, 2.85-21.5), where it was also associated independently with young age (adjusted OR, 0.85; 95% CI, 0.80-0.93) and monthly income (adjusted OR, 0.88; 95% CI, 0.83-0.96).

INTERPRETATION

In rural areas of DRC, producing or selling charcoal is associated with a higher risk of COPD.

The epithelial barrier theory and its associated diseases

The prevalence of many chronic noncommunicable diseases has been steadily rising over the past six decades. During this time, over 350,000 new chemical substances have been introduced to the lives of humans. In recent years, the epithelial barrier theory came to light explaining the growing prevalence and exacerbations of these diseases worldwide. It attributes their onset to a functionally impaired epithelial barrier triggered by the toxicity of the exposed substances, associated with microbial dysbiosis, immune system activation, and inflammation. Diseases encompassed by the epithelial barrier theory share common features such as an increased prevalence after the 1960s or 2000s that cannot (solely) be accounted for by the emergence of improved diagnostic methods. Other common traits include epithelial barrier defects, microbial dysbiosis with loss of commensals and colonization of opportunistic pathogens, and circulating inflammatory cells and cytokines. In addition, practically unrelated diseases that fulfill these criteria have started to emerge as multimorbidities during the last decades. Here, we provide a comprehensive overview of diseases encompassed by the epithelial barrier theory and discuss evidence and similarities for their epidemiology, genetic susceptibility, epithelial barrier dysfunction, microbial dysbiosis, and tissue inflammation.

Self-reported exposure to dust and diesel exhaust, respiratory symptoms, and use of respiratory protective equipment among Arctic miners

Arctic miners face significant risks from diesel exhaust and dust exposure, potentially leading to adverse respiratory health. Employers must limit harmful exposures, using personal protective equipment (PPE) as a last line of defense. This study explored the association between reported respiratory exposure and symptoms, and PPE training and usage. Data from the MineHealth study (2012-2014) included a total of 453 Arctic open pit miners in Norway, Sweden, and Finland. Participants answered questions on exposure to dust and diesel exhaust, respiratory symptoms, and PPE use, in addition to age, gender, BMI, smoking, and self-rated health. Estimated exposure to dust was common, reported by 91%, 80%, and 82% and that of diesel exhaust by 84%, 43%, and 47% of workers in Sweden, Finland, and Norway, respectively. Reported dust exposure was significantly related to respiratory symptoms (OR 2.2, 95% CI 1.3-3.7), diesel exposure increased the occurrence of wheezing (OR 2.6, 95% CI 1.3-5.4). PPE use varied between the studied mines. Non-use was common and related to reduced visibility, wetness, skin irritation and fogging of the respiratory PPE. Future research should employ more precise exposure assessment, respiratory function as well as explore the reasons behind the non-compliance of PPE use.

Air pollution, weather and positive airway pressure treatment adherence in adults with sleep apnea: a retrospective community-based repeated-measures longitudinal study

We assessed the relation between air pollution, weather, and adherence to positive airway pressure (PAP) therapy in a retrospective community-based repeated-measures study of adults with obstructive sleep apnea who purchased PAP devices from a registered provider between 2013 and 2017 (Ottawa, Ontario, Canada) and had at least one day of data. Daily PAP-derived data, air pollution, and weather databases were linked using postal code. The exposures were mean nocturnal (8:00 p.m. to 8:00 a.m.) (i) residential concentrations of nitrogen dioxide (NO2), fine particulate matter <=2.5 μm (PM2.5), ozone (O3), and Air Quality Health Index (AQHI), and (ii) temperature, relative humidity, and barometric pressure. Covariates in the main model were demographics, season, exposure year, and PAP therapy mode. We analysed 8148 adults (median age of 54 years and 61% men) and 2,071,588 days of data. Based on daily data, the median (interquartile range) daily PAP usage was 416 (323-487) min. Using mixed-effect regression analyses to incorporate daily data and clustering by individuals, we found a statistically significant decrease in adherence for increased levels of NO2, PM2.5, and AQHI. The largest effect was for NO2: a decrease in daily PAP use while comparing the highest versus lowest quartiles (Qs) was 3.4 (95% confidence interval [CI] 2.8-3.9) min. Decreased PAP adherence was also associated with increased temperature (Q4 versus Q1: 2.6 [95% CI: 1.5-3.7] min) and decreased barometric pressure (Q1 versus Q4: 2.0 [95% CI 1.5-2.5] min). We observed modest but statistically significant acute effects of air pollution and weather on daily PAP adherence.

LungVis 1.0: an automatic AI-powered 3D imaging ecosystem unveils spatial profiling of nanoparticle delivery and acinar migration of lung macrophages

Targeted (nano-)drug delivery is essential for treating respiratory diseases, which are often confined to distinct lung regions. However, spatio-temporal profiling of drugs or nanoparticles (NPs) and their interactions with lung macrophages remains unresolved. Here, we present LungVis 1.0, an AI-powered imaging ecosystem that integrates light sheet fluorescence microscopy with deep learning-based image analysis pipelines to map NP deposition and dosage holistically and quantitatively across bronchial and alveolar (acinar) regions in murine lungs for widely-used bulk-liquid and aerosol-based delivery methods. We demonstrate that bulk-liquid delivery results in patchy NP distribution with elevated bronchial doses, whereas aerosols achieve uniform deposition reaching distal alveoli. Furthermore, we reveal that lung tissue-resident macrophages (TRMs) are dynamic, actively patrolling and redistributing NPs within alveoli, contesting the conventional paradigm of TRMs as static entities. LungVis 1.0 provides an advanced framework for exploring pulmonary delivery dynamics and deepening insights into TRM-mediated lung immunity.

Influence of air pollution on the nonaccidental death before and after the outbreak of COVID-19

BACKGROUND

During the COVID-19 pandemic, non-therapeutic interventions (NPIs), such as traffic restrictions, work stoppages, and school suspensions, have led to a sharp decline in the concentration of air pollutants in the epidemic sites. However, few studies focused on the impact of air pollutant changes on the risk of nonaccidental death.

METHOD

We selected Yancheng City, China, as the study site and applied a Generalized Additive Model (GAM) based on the quasi-Poisson distribution to evaluate the impact of atmospheric pollutants exposure on the nonaccidental death of local residents. The time span of this study was set from January 1, 2013, to December 21, 2022, that is, before and after the outbreak of COVID-19.

RESULTS

The concentration of some air pollutants has greatly varied after the outbreak of COVID-19, with a significant decline for PM2.5 (- 43.4%), PM10 (- 38.5%), SO2 (- 62.9%), and NO2 (- 22.6%), but an increase for O3 (+ 4.3%). Comparative analysis showed that PM2.5 contributed to an increased risk of nonaccidental death after the outbreak of COVID-19. With an increase in PM2.5 by 10 µg/m³, the excess relative risks (ER) of nonaccidental death of residents increased by 1.01% (95%CI: 0.19%,1.84%). The stratified analysis revealed that air pollutants impacted nonaccidental deaths in both men and women before the outbreak of COVID-19. After the outbreak of COVID-19, PM10 had a significant effect on male nonaccidental deaths. The concentrations of PM2.5, PM10, and SO2 increased by 10 µg/m³, the ER of PM2.5, PM10, and SO2 on female nonaccidental death increased by 1.52% (0.38%,2.67%), 0.58% (0.02%,1.13%), and 15.09% (5.73%,25.28%), respectively. Before the outbreak of COVID-19, five air pollutants had an impact on the death of residents from cardiovascular disease (CVD). After the outbreak of COVID-19, only PM10 significantly affected the death risk of CVD. In addition, we discovered that PM2.5, PM10, and SO2 significantly impacted the risk of death due to respiratory diseases before and after the outbreak of COVID-19.

CONCLUSIONS

Air pollutants have different effects on nonaccidental deaths before and after the COVID-19 outbreak. A decrease in air pollutant concentration due to the NPIs for COVID-19 had a significant effect on the reduction of the risk of nonaccidental death.

Exosomal miR-129-2-3p promotes airway epithelial barrier disruption in PM2.5-aggravated asthma

Particulate matter 2.5 (PM2.5) exposure is intricately linked to asthma exacerbations. Damage to the airway epithelial barrier function serves as an initiating factor for asthma attacks and worsening symptoms. In recent years, numerous exosomal microRNAs (miRNAs) have emerged as potential biomarkers for diagnosing asthma. However, the mechanisms by which PM2.5-induced exosomes exacerbate asthma remain unclear. This study aims to investigate the role of exosomal miR-129-2-3p in regulating airway epithelial cell barrier function, its potential targets, and signaling pathways involved in PM2.5-induced aggravation of asthma. In this study, miR-129-2-3p is highly expressed in plasma exosomes from patients with asthma, mouse lung tissue and plasma exosomes, and exosomes produced by PM2.5-stimulated 16HBE cells. Moreover, the exposure level of PM2.5 is positively correlated with exosomal miR-129-2-3p in plasma in patients with asthma. As the concentration of PM2.5 increases, the synthesis of connexin (ZO-1, occludin, and E-cadherin) is gradually weakened, while the content of inflammatory factors (IL-6, IL-8, and TNF-α) is notably upregulated in PM2.5 exacerbated asthmatic mice. PM2.5-induced exosomes can decrease the level of connexin, enhance cell permeability and promote the secretion of inflammatory factors in 16HBE cells. TIAM1, a specific target gene for miR-129-2-3p, regulates the synthesis of connexin. Exosomal miR-129-2-3p exacerbates airway epithelial barrier dysfunction by targeted inhibition of the TIAM1/RAC1/PAK1 signaling pathway in PM2.5 aggravated asthma. In contrast, blocking miR-129-2-3p may be an alternative approach to therapeutic intervention in asthma.

PM10 dysregulates epithelial barrier function in human corneal epithelial cells that is restored by antioxidant SKQ1

Exposure to airborne particulate <10 μm (PM10) adversely affects the ocular surface. This study tested PM10 on epithelial barrier integrity in immortalized human corneal epithelial cells (HCE-2) and mouse cornea, and whether antioxidant SKQ1 is restorative. HCE-2 were exposed to 100 μg/ml PM10 ± SKQ1 for 24 h. An Electric Cell-Substrate Impedance Sensing (ECIS) system monitored the impact of PM10. RT-PCR, western blotting and immunofluorescence measured levels of barrier and associated proteins, stanniocalcin 2 (STC2), and a kit measured total calcium. In vivo, female C57BL/6 mice were exposed to either control air or PM10 (±SKQ1) in a whole-body exposure chamber, and barrier associated proteins tested. Tight junction and mucins proteins in the cornea were tested. In HCE-2, PM0 vs control significantly reduced mRNA and protein levels of tight junction and adherence proteins, and mucins. ECIS data demonstrated that PM10 vs control cells exhibited a significant decrease in epithelial barrier strength at 4000 Hz indicated by reduced impedance and resistance. PM10 also upregulated STC2 protein and total calcium levels. In vivo, PM10 vs control reduced zonula occludens 1 and mucins. SKQ1 pre-treatment reversed PM10 effects both in vitro and in vivo. In conclusion, PM10 exposure reduced tight junction and mucin proteins, and compromised the seal between cells in the corneal epithelium leading to decreased epithelial barrier strength. This effect was reversed by SKQ1. Since the corneal epithelium forms the first line of defense against air pollutants, including PM10, preserving its integrity using antioxidants such as SKQ1 is crucial in reducing the occurrence of ocular surface disorders.

Effects of MAL gene knockout on lung tissue morphology and on E-cad and α-SMA expression in asthma mouse models

OBJECTIVES

To investigate the effects of myelin- and lymphocyte-associated protein (MAL) gene knockout on the morphological structure of lung tissue and the expression of E-cadherin (E-cad) and alpha-smooth muscle actin (α-SMA) in an asthmatic mouse model.

METHODS

Twenty-four specific pathogen-free (SPF) C57BL/6J mice were divided into four groups: the wild-type normal (WT/SAL), wild-type asthmatic (WT/OVA), gene knockout normal (MAL-/-/SAL), and gene knockout asthmatic (MAL-/-/OVA) groups. The establishment of the asthma mouse models was confirmed by evaluating behavioral symptoms and histopathological H&E and Masson staining. Western blotting and RT-qPCR were used to measure E-cad and α-SMA expression levels in lung tissues.

RESULTS

H&E staining of mouse lung tissues from WT/OVA, MAL-/-/SAL, and MAL-/-/OVA groups revealed a thickened bronchial wall, irregular lumen edge, locally fallen mucosal epithelium, and inflammatory cell infiltration compared with those of the WT/SAL group. In the WT and MAL-/- groups, the proportion of Masson-stained tissues in the OVA group was greater than that in the SAL group (p < 0.05). Compared with those in the WT/SAL group, the expression levels of α-SMA mRNA and protein were increased, while those of E-cad were decreased in the WT/OVA group (p < 0.01). Similarly, compared with those in the MAL-/-/SAL group, the expression levels of E-cad mRNA and protein were increased, while those of α-SMA were decreased in the MAL-/-/OVA group (p < 0.01). All these differences were statistically significant (p < 0.01).

CONCLUSIONS

The MAL gene contributes to EMT inhibition and the stability of the airway barrier under normal physiological conditions by regulating E-cad and α-SMA expression.

The potential effects of climate change on non-cystic fibrosis bronchiectasis in children

Climate change may have devastating effects on the pathogenesis of non-cystic fibrosis bronchiectasis in children since it affects the biological cycle of the respiratory pathogens and alters the human respiratory defense mechanisms. Bronchiectasis in children has been identified as an emerging global epidemic that has attracted the attention of the medical community over recent years. Pediatric pulmonologists should be aware of the consequences of climate change on children with bronchiectasis and plan strategies to ameliorate these effects.

Environmental pollutant 3-methyl-4-nitrophenol promotes the expression of oncostatin M to exacerbate airway allergic inflammation

Asthma exacerbation is a common clinical occurrence. The causal factors are not fully understood yet. Environmental pollution is linked to asthma exacerbation. The objective of this study is to elucidate the role of 3-methyl-4-nitrophenol (MNP), an environmental pollutant, in asthma exacerbation. In this study, an airway allergy mouse model was established with ovalbumin as a specific antigen with or without the presence of MNP. The results showed that, in a mouse model, the intensity of airway allergy was significantly increased by exposure to MNP. RNAseq results showed an increase in endoplasmic reticulum (ER) stress-associated molecules and the Osm expression in airway epithelial cells of mice with airway allergy. Exposure of epithelial cells to MNP in culture induced the expression of oncostatin M (OSM) and ER stress associated molecules. The OSM receptor was expressed by macrophages. OSM could drive macrophages to produce tumor necrosis factor-α (TNF-α). Inhibition of PERK, one of the key molecules of ER stress, or depletion of OSM receptor in macrophages, could effectively attenuate the MNP/ovalbumin protocol induced airway allergy. To sum up, by promoting ER stress, environmental pollutant MNP can cause airway epithelial cells to produce OSM. The latter induces macrophages to produce TNF-α, which can exacerbate airway allergy.

Short-term exposure to sulfur dioxide and the occurrence of chronic obstructive pulmonary disease: An updated systematic review and meta-analysis based on risk of bias and certainty of evidence

Several studies have documented a relationship between short-term exposure to atmospheric sulfur dioxide (SO2) and chronic obstructive pulmonary disease (COPD). However, findings vary across different regions. This meta-analysis employed a random-effects model to calculate the combined risk estimate for each 10-μg/m3 increase in ambient SO2 concentration. Subgroup analysis aimed to identify sources of heterogeneity. To assess potential bias, studies were evaluated using a domain-based assessment tool developed by the World Health Organization. Sensitivity analyses, based on bias risk, explored how model assumptions influenced associations. An evidence certainty framework was used to evaluate overall evidence quality. The study protocol was registered with PROSPERO (CRD42023446823). We thoroughly reviewed 191 full-text articles, ultimately including 15 in the meta-analysis. The pooled relative risk for COPD was 1.26 (95 % CI 0.94-1.70) per 10-μg/m3 increase in ambient SO2. Eleven studies were deemed high risk due to inadequate handling of missing data. Overall evidence certainty was rated as medium. Given SO2's significant public health implications, continuous monitoring is crucial. Future research should include countries in Africa and Oceania to enhance global understanding of atmospheric SO2-related health issues.

COPD-Like Phenotypes in TBC-Treated Mice Can be Effectively Alleviated via Estrogen Supplement

Tris(2,3-dibromopropyl) isocyanurate (TBC), recognized as an endocrine disruptor, can cause inflammatory injury to the lung tissue of mice. To investigate the specific respiratory effects of TBC, male C57BL/6J mice were administered a daily dose of 20 mg/kg of TBC over 14 days. Postexposure, these mice developed chronic obstructive pulmonary disease (COPD)-like symptoms characterized by inflammatory lung damage and functional impairment. In light of the antiestrogenic properties of TBC, we administrated estradiol (E2) to investigate its potential protective role against TBC-induced damage and found that the coexposure of E2 notably mitigated the COPD-like phenotypes. Immunohistochemical analysis revealed that TBC exposure reduced estrogen receptor alpha (ERα) expression and increased nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, while E2 treatment rebalanced the expression levels of ERα and NF-κB to their normative states. Our findings indicate that TBC, as an antiestrogenic agent, may contribute to the pathogenesis of COPD through an ERα-mediated inflammatory pathway, but that E2 treatment could reverse the impairment, providing a potentially promising remedial treatment. Given the lung status as a primary target of air pollution, the presence of antiestrogenic compounds like TBC in atmospheric particulates presents a significant concern, with the potential to exacerbate respiratory conditions such as COPD and pneumonia.

Associations of long-term exposure to air pollution and greenness with incidence of chronic obstructive pulmonary disease in Northern Europe: The Life-GAP project

BACKGROUND

Prolonged exposure to air pollution has been linked to adverse respiratory health, yet the evidence concerning its association with chronic obstructive pulmonary disease (COPD) is inconsistent. The evidence of a greenness effect on chronic respiratory diseases is limited.

OBJECTIVE

This study aimed to investigate the association between long-term exposure to particulate matter (PM2.5 and PM10), black carbon (BC), nitrogen dioxide (NO2), ozone (O3) and greenness (as measured by the normalized difference vegetation index - NDVI) and incidence of self-reported chronic bronchitis or COPD (CB/COPD).

METHODS

We analyzed data from 5355 adults from 7 centers participating in the Respiratory Health in Northern Europe (RHINE) study. Mean exposures to air pollution and greenness were assessed at available residential addresses in 1990, 2000 and 2010 using air dispersion models and satellite data, respectively. Poisson regression with log person-time as an offset was employed to analyze the association between air pollution, greenness, and CB/COPD incidence, adjusting for confounders.

RESULTS

Overall, there were 328 incident cases of CB/COPD during 2010-2023. Despite wide statistical uncertainty, we found a trend for a positive association between NO2 exposure and CB/COPD incidence, with incidence rate ratios (IRRs) per 10 μg/m³ difference ranging between 1.13 (95% CI: 0.90-1.41) in 1990 and 1.18 (95% CI: 0.96-1.45) in 2000. O3 showed a tendency for inverse association with CB/COPD incidence (IRR from 0.84 (95% CI: 0.66-1.07) in 2000 to 0.88 (95% CI: 0.69-1.14) in 2010. No consistent association was found between PM, BC and greenness with CB/COPD incidence across different exposure time windows.

CONCLUSION

Consistent with prior research, our study suggests that individuals exposed to higher concentrations of NO2 may face an elevated risk of developing COPD, although evidence remains inconclusive. Greenness was not associated with CB/COPD incidence, while O3 showed a tendency for an inverse association with the outcome.

Geospatial modelling of ambient air pollutants and chronic obstructive pulmonary diseases at regional scale in Pakistan

Pakistan is among the South Asian countries mostly vulnerable to the negative health impacts of air pollution. In this context, the study aimed to analyze the spatiotemporal patterns of chronic obstructive pulmonary disease (COPD) incidence and its relationship with air pollutants including aerosol absorbing index (AAI), carbon monoxide, sulfur dioxide (SO2), and nitrogen dioxide. Spatial scan statistics were employed to identify temporal, spatial, and spatiotemporal clusters of COPD. Generalized linear regression (GLR) and random forest (RF) models were utilized to evaluate the linear and non-linear relationships between COPD and air pollutants for the years 2019 and 2020. The findings revealed three spatial clusters of COPD in the eastern and central regions, with a high-risk spatiotemporal cluster in the east. The GLR identified a weak linear relationship between the COPD and air pollutants with R2 = 0.1 and weak autocorrelation with Moran's index = -0.09. The spatial outcome of RF model provided more accurate COPD predictions with improved R2 of 0.8 and 0.9 in the respective years and a very low Moran's I = -0.02 showing a random residual distribution. The RF findings also suggested AAI and SO2 to be the most contributing predictors for the year 2019 and 2020. Hence, the strong association of COPD clusters with some air pollutants highlight the urgency of comprehensive measures to combat air pollution in the region to avoid future health risks.

Pyroptosis, gasdermins and allergic diseases

Pyroptosis is an inflammatory form of programmed cell death that is distinct from necrosis and apoptosis. Pyroptosis is primarily mediated by the gasdermin family of proteins (GSDMA-E and PVJK), which, when activated by proteolytic cleavage, form pores in the plasma membrane, leading to cell death. While much of the past research on pyroptosis has focused on its role in cancer, metabolic disorders, and infectious diseases, recent experimental and observational studies have begun to implicate pyroptosis in allergic diseases. These studies suggest that gasdermin-mediated pyroptosis contributes to the development of allergic conditions and could offer novel targets for therapy. Here, we review our current understanding of pyroptosis with an emphasis on the role of gasdermins as executioners of pyroptosis and potential mediators to allergic disease. We highlight new discoveries that establish a mechanistic link between the biochemical actions of gasdermins and the onset of allergic diseases. Additionally, we discuss how pyroptosis and gasdermins might contribute to the dysfunction of epithelial barrier, a key factor believed to initiate the progression of various allergic diseases.

Epithelial barrier dysfunction and microbial dysbiosis: exploring the pathogenesis and therapeutic strategies for Crohn's disease

Crohn's disease (CD), a chronic gastrointestinal inflammatory disease, is becoming more widespread worldwide. Crohn's disease is caused by gut microbiota changes, genetics, environmental stresses, and immunological responses. Current treatments attempt to achieve long-term remission and avoid complications, delaying disease progression. Immunosuppressive measures and combination medicines should be started early for high-risk patients. These medicines monitor inflammatory indicators and adjust as needed. The epithelial barrier helps defend against physical, chemical, and immunological threats. When tissues' protective barrier breaks down, the microbiome may reach the layer underneath. Unbalanced microbial populations and inflammation impair healing and adjustment. Inflammatory cells infiltrating sensitive tissues aggravate the damage and inflammation. This approach promotes chronic inflammatory diseases. The epithelial barrier hypothesis states that hereditary and environmental variables cause epithelial tissue inflammation. This review focuses on how epithelial barrier break-down and microbial dysbiosis cause Crohn's disease and current advances in understanding the epithelial barrier, immune system, and microbiome. Additionally, investigate treatments that restore barrier integrity and promote microbial balance. Overall, it stresses the role of epithelial barrier failure and microbial dysbiosis in Crohn's disease development and discusses current advances in understanding the barrier, immunological responses, and microbiota.

Impact of environmental air pollution on respiratory health and function

Environmental air pollution presents a considerable risk to global respiratory health. If critical levels are exceeded, inhaled pollutants can lead to the development of respiratory dysfunction and provoke exacerbation in those with pre-existing chronic respiratory disease. Over 90% of the global population currently reside in areas where environmental air pollution is considered excessive-with adverse effects ranging from acute airway irritation to complex immunomodulatory alterations. This narrative review provides an up-to-date perspective concerning the impact of environmental air pollution on respiratory health and function and describes the underpinning mechanisms that contribute to the development and progression of chronic respiratory disease.

Gene expression changes in mouse lung induced by subacute inhalation of PM10-rich particulate matter

INTRODUCTION

Particulate matter (PM) air pollution is associated with an increased incidence of lung diseases, but the underlying mechanisms have not been fully elucidated. In this study, a mouse model of subacute lung inflammation was employed to investigate the cellular responses and gene expression changes induced by exposure to natural ambient air pollution.

METHODS

C57BL/6J mice were exposed to road dust (primarily PM10) at 150 µg/m³ for 21 days (8 h/day) through a nose-only inhalation exposure system. Lung tissues were analyzed for the expression of proinflammatory signaling, oxidative stress, and fibrosis markers. RNA-sequencing analysis was conducted to identify differentially expressed genes (DEGs). A gene ontology over-representation analysis was performed to identify the altered genetic pathways.

RESULTS

Elevated levels of proinflammatory cytokines, including IL-1β, IL-6, and TNF-α, and an increase in phosphorylated MAPK were determined in the road dust exposure group compared to the control group. Histopathological examinations revealed more severe lung inflammation and damage in the exposed mice, including fibrosis and bronchiolar hyperplasia. Gene expression profiling identified 108 DEGs, with decreases in most except genes such as Krt15 and Reg3g. The protein-protein interaction network analysis together with text-mining identified 18 key hub genes, associated with fatty acid oxidation, lipid metabolism, and peroxisomes.

CONCLUSION

This study identified key genes, signaling pathways, and cellular responses in mouse lung affected by road dust exposure. These findings contribute to a deeper understanding of the transcriptional and cellular responses induced by subacute exposure to the PM in road dust.

PM2.5 Exposure Inhibits Transepithelial Anion Short-circuit Current by Downregulating P2Y2 Receptor/CFTR Pathway

Fine particulate matter (PM2.5) can damage airway epithelial barriers. The anion transport system plays a crucial role in airway epithelial barriers. However, the detrimental effect and mechanism of PM2.5 on the anion transport system are still unclear. In this study, airway epithelial cells and ovalbumin (OVA)-induced asthmatic mice were used. In transwell model, the adenosine triphosphate (ATP)-induced transepithelial anion short-circuit current (Isc) and airway surface liquid (ASL) significantly decreased after PM2.5 exposure. In addition, PM2.5 exposure decreased the expression levels of P2Y2R, CFTR and cytoplasmic free-calcium, but ATP can increase the expressions of these proteins. PM2.5 exposure increased the levels of Th2-related cytokines of bronchoalveolar lavage fluid, lung inflammation, collagen deposition and hyperplasisa of goblet cells. Interestingly, the administration of ATP showed an inhibitory effect on lung inflammation induced by PM2.5. Together, our study reveals that PM2.5 impairs the ATP-induced transepithelial anion Isc through downregulating P2Y2R/CFTR pathway, and this process may participate in aggravating airway hyperresponsiveness and airway inflammation. These findings may provide important insights on PM2.5-mediated airway epithelial injury.

Breathing in danger: Understanding the multifaceted impact of air pollution on health impacts

Air pollution, a pervasive environmental threat that spans urban and rural landscapes alike, poses significant risks to human health, exacerbating respiratory conditions, triggering cardiovascular problems, and contributing to a myriad of other health complications across diverse populations worldwide. This article delves into the multifarious impacts of air pollution, utilizing cutting-edge research methodologies and big data analytics to offer a comprehensive overview. It highlights the emergence of new pollutants, their sources, and characteristics, thereby broadening our understanding of contemporary air quality challenges. The detrimental health effects of air pollution are examined thoroughly, emphasizing both short-term and long-term impacts. Particularly vulnerable populations are identified, underscoring the need for targeted health risk assessments and interventions. The article presents an in-depth analysis of the global disease burden attributable to air pollution, offering a comparative perspective that illuminates the varying impacts across different regions. Furthermore, it addresses the economic ramifications of air pollution, quantifying health and economic losses, and discusses the implications for public policy and health care systems. Innovative air pollution intervention measures are explored, including case studies demonstrating their effectiveness. The paper also brings to light recent discoveries and insights in the field, setting the stage for future research directions. It calls for international cooperation in tackling air pollution and underscores the crucial role of public awareness and education in mitigating its impacts. This comprehensive exploration serves not only as a scientific discourse but also as a clarion call for action against the invisible but insidious threat of air pollution, making it a vital read for researchers, policymakers, and the general public.

Fine particulate matter manipulates immune response to exacerbate microbial pathogenesis in the respiratory tract

Particulate matter with a diameter ≤2.5 μm (PM2.5) poses a substantial global challenge, with a growing recognition of pathogens contributing to diseases associated with exposure to PM2.5 Recent studies have focused on PM2.5, which impairs the immune cells in response to microbial infections and potentially contributes to the development of severe diseases in the respiratory tract. Accordingly, changes in the respiratory immune function and microecology mediated by PM2.5 are important factors that enhance the risk of microbial pathogenesis. These factors have garnered significant interest. In this review, we summarise recent studies on the potential mechanisms involved in PM2.5-mediated immune system disruption and exacerbation of microbial pathogenesis in the respiratory tract. We also discuss crucial areas for future research to address the gaps in our understanding and develop effective strategies to combat the adverse health effects of PM2.5.

Revisiting airway epithelial dysfunction and mechanisms in chronic obstructive pulmonary disease: the role of mitochondrial damage

Chronic exposure to environmental hazards causes airway epithelial dysfunction, primarily impaired physical barriers, immune dysfunction, and repair or regeneration. Impairment of airway epithelial function subsequently leads to exaggerated airway inflammation and remodeling, the main features of chronic obstructive pulmonary disease (COPD). Mitochondrial damage has been identified as one of the mechanisms of airway abnormalities in COPD, which is closely related to airway inflammation and airflow limitation. In this review, we evaluate updated evidence for airway epithelial mitochondrial damage in COPD and focus on the role of mitochondrial damage in airway epithelial dysfunction. In addition, the possible mechanism of airway epithelial dysfunction mediated by mitochondrial damage is discussed in detail, and recent strategies related to airway epithelial-targeted mitochondrial therapy are summarized. Results have shown that dysregulation of mitochondrial quality and oxidative stress may lead to airway epithelial dysfunction in COPD. This may result from mitochondrial damage as a central organelle mediating abnormalities in cellular metabolism. Mitochondrial damage mediates procellular senescence effects due to mitochondrial reactive oxygen species, which effectively exacerbate different types of programmed cell death, participate in lipid metabolism abnormalities, and ultimately promote airway epithelial dysfunction and trigger COPD airway abnormalities. These can be prevented by targeting mitochondrial damage factors and mitochondrial transfer. Thus, because mitochondrial damage is involved in COPD progression as a central factor of homeostatic imbalance in airway epithelial cells, it may be a novel target for therapeutic intervention to restore airway epithelial integrity and function in COPD.

Effect of Air Pollutants on Allergic Inflammation in Structural Cells of the Nasal Mucosa

OBJECTIVES

Air pollution is an increasing global concern, and its effect on allergic inflammation has attracted the attention of many researchers. Particulate matter (PM) is a major component of ambient air pollution, and heavy metals are the primary toxic constituents of PM. As previous studies on the impact of air pollutants on allergic inflammation did not adequately mimic real-world atmospheric exposure, we developed an experimental model to investigate the effects of aerosolized air pollutants on nasal epithelial cells and fibroblasts.

METHODS

We collected particulate matter 2.5 (PM2.5) samples from ambient 24-hour air samples obtained in Seoul from August 2020 to August 2022, and then conducted component analysis for metallic constituents. Primary nasal epithelial cells and nasal fibroblasts, obtained and cultured from the turbinate tissues of human participants, were treated with PM2.5. The associations of heavy metals identified from the component analysis with cytokine expression were investigated. A three-dimensional (3D)-hybrid culture model, consisting of co-culture of an air-liquid interface and nasal fibroblast spheroids, was constructed to observe the impact of aerosolized air pollutants.

RESULTS

Among the heavy metals, Si was the predominant component of PM2.5, and Zn showed the highest correlation with the concentration of PM2.5 in Seoul. PM2.5, Zn, and Si increased the production of epithelial cell-derived cytokines, and PM2.5 and Zn exhibited similar trends with one another. Exposure of the 3D-hybrid model to aerosolized PM2.5 and Zn resulted in elevated periostin, alpha-smooth muscle actin, and fibronectin expression in fibroblast spheroids, and those without an epithelial barrier exhibited a similar increase in periostin expression.

CONCLUSION

Ambient air pollutants in the form of aerosols increase the expression of allergic inflammatory cytokines in both nasal epithelial cells and fibroblasts. Regulations on air pollution will help reduce the global burden of allergic diseases in the future.

Airborne indoor allergen serine proteases and their contribution to sensitisation and activation of innate immunity in allergic airway disease

Common airborne allergens (pollen, animal dander and those from fungi and insects) are the main triggers of type I allergic disorder in the respiratory system and are associated with allergic rhinitis, allergic asthma, as well as immunoglobulin E (IgE)-mediated allergic bronchopulmonary aspergillosis. These allergens promote IgE crosslinking, vasodilation, infiltration of inflammatory cells, mucosal barrier dysfunction, extracellular matrix deposition and smooth muscle spasm, which collectively cause remodelling of the airways. Fungus and insect (house dust mite and cockroaches) indoor allergens are particularly rich in proteases. Indeed, more than 40 different types of aeroallergen proteases, which have both IgE-neutralising and tissue-destructive activities, have been documented in the Allergen Nomenclature database. Of all the inhaled protease allergens, 85% are classed as serine protease activities and include trypsin-like, chymotrypsin-like and collagenolytic serine proteases. In this article, we review and compare the allergenicity and proteolytic effect of allergen serine proteases as listed in the Allergen Nomenclature and MEROPS databases and highlight their contribution to allergic sensitisation, disruption of the epithelial barrier and activation of innate immunity in allergic airways disease. The utility of small-molecule inhibitors of allergen serine proteases as a potential treatment strategy for allergic airways disease will also be discussed.

Impact of climate change on paediatric respiratory health: pollutants and aeroallergens

Paediatric populations are particularly vulnerable to respiratory diseases caused and exacerbated by aeroallergens, pollutants and infectious agents. Worsening climate change is expected to increase the prevalence of pollutants and aeroallergens while amplifying disease severity and causing disproportionate effects in under-resourced areas. The purpose of this narrative review is to summarise the role of anthropogenic climate change in the literature examining the future impact of aeroallergens, pollutants and infectious agents on paediatric respiratory diseases with a focus on equitable disease mitigation. The aeroallergens selected for discussion include pollen, dust mites and mould as these are prevalent triggers of paediatric asthma worldwide. Human rhinovirus and respiratory syncytial virus are key viruses interacting with climate change and pollution and are primary causal agents of viral respiratory disease. Within this review, we present the propensity for aeroallergens, climate change and pollution to synergistically exacerbate paediatric respiratory disease and outline measures that can ameliorate the expected increase in morbidity and severity of disease through a health equity lens. We support shifting from fossil fuels to renewable energy worldwide, across sectors, as a primary means of reducing increases in morbidity.

The airway epithelium: an orchestrator of inflammation, a key structural barrier and a therapeutic target in severe asthma

Asthma is a disease of heterogeneous pathology, typically characterised by excessive inflammatory and bronchoconstrictor responses to the environment. The clinical expression of the disease is a consequence of the interaction between environmental factors and host factors over time, including genetic susceptibility, immune dysregulation and airway remodelling. As a critical interface between the host and the environment, the airway epithelium plays an important role in maintaining homeostasis in the face of environmental challenges. Disruption of epithelial integrity is a key factor contributing to multiple processes underlying asthma pathology. In this review, we first discuss the unmet need in asthma management and provide an overview of the structure and function of the airway epithelium. We then focus on key pathophysiological changes that occur in the airway epithelium, including epithelial barrier disruption, immune hyperreactivity, remodelling, mucus hypersecretion and mucus plugging, highlighting how these processes manifest clinically and how they might be targeted by current and novel therapeutics.

Impact of particulate air pollution on airway injury and epithelial plasticity; underlying mechanisms

Air pollution plays an important role in the mortality and morbidity of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Particulate matter (PM) is a significant fraction of air pollutants, and studies have demonstrated that it can cause airway inflammation and injury. The airway epithelium forms the first barrier of defense against inhaled toxicants, such as PM. Airway epithelial cells clear airways from inhaled irritants and orchestrate the inflammatory response of airways to these irritants by secreting various lipid mediators, growth factors, chemokines, and cytokines. Studies suggest that PM plays an important role in the pathogenesis of chronic airway diseases by impairing mucociliary function, deteriorating epithelial barrier integrity, and inducing the production of inflammatory mediators while modulating the proliferation and death of airway epithelial cells. Furthermore, PM can modulate epithelial plasticity and airway remodeling, which play central roles in asthma and COPD. This review focuses on the effects of PM on airway injury and epithelial plasticity, and the underlying mechanisms involving mucociliary activity, epithelial barrier function, airway inflammation, epithelial-mesenchymal transition, mesenchymal-epithelial transition, and airway remodeling.

Use of human airway smooth muscle in vitro and ex vivo to investigate drugs for the treatment of chronic obstructive respiratory disorders

Isolated airway smooth muscle has been extensively investigated since 1840 to understand the pharmacology of airway diseases. There has often been poor predictability from murine experiments to drugs evaluated in patients with asthma or chronic obstructive pulmonary disease (COPD). However, the use of isolated human airways represents a sensible strategy to optimise the development of innovative molecules for the treatment of respiratory diseases. This review aims to provide updated evidence on the current uses of isolated human airways in validated in vitro methods to investigate drugs in development for the treatment of chronic obstructive respiratory disorders. This review also provides historical notes on the pioneering pharmacological research on isolated human airway tissues, the key differences between human and animal airways, as well as the pivotal differences between human medium bronchi and small airways. Experiments carried out with isolated human bronchial tissues in vitro and ex vivo replicate many of the main anatomical, pathophysiological, mechanical and immunological characteristics of patients with asthma or COPD. In vitro models of asthma and COPD using isolated human airways can provide information that is directly translatable into humans with obstructive lung diseases. Regardless of the technique used to investigate drugs for the treatment of chronic obstructive respiratory disorders (i.e., isolated organ bath systems, videomicroscopy and wire myography), the most limiting factors to produce high-quality and repeatable data remain closely tied to the manual skills of the researcher conducting experiments and the availability of suitable tissue.

NLRP3 inflammasome mediates abnormal epithelial regeneration and distal lung remodeling in silica‑induced lung fibrosis

NOD-like receptor protein 3 (NLRP3) inflammasome is closely related to silica particle‑induced chronic lung inflammation but its role in epithelial remodeling, repair and regeneration in the distal lung during development of silicosis remains to be elucidated. The present study aimed to determine the effects of the NLRP3 inflammasome on epithelial remodeling and cellular regeneration and potential mechanisms in the distal lung of silica‑treated mice at three time points. Pulmonary function assessment, inflammatory cell counting, enzyme‑linked immunosorbent assay, histological and immunological analyses, hydroxyproline assay and western blotting were used in the study. Single intratracheal instillation of a silica suspension caused sustained NLRP3 inflammasome activation in the distal lung. Moreover, a time‑dependent increase in airway resistance and a decrease in lung compliance accompanied progression of pulmonary fibrosis. In the terminal bronchiole, lung remodeling including pyroptosis (membrane‑distributed GSDMD+), excessive proliferation (Ki67+), mucus overproduction (mucin 5 subtype AC and B) and epithelial‑mesenchymal transition (decreased E‑Cadherin+ and increased Vimentin+), was observed by immunofluorescence analysis. Notably, aberrant spatiotemporal expression of the embryonic lung stem/progenitor cell markers SOX2 and SOX9 and ectopic distribution of bronchioalveolar stem cells were observed in the distal lung only on the 7th day after silica instillation (the early inflammatory phase of silicosis). Western blotting revealed that the Sonic hedgehog/Glioma‑associated oncogene (Shh/Gli) and Wnt/β‑catenin pathways were involved in NLRP3 inflammasome activation‑mediated epithelial remodeling and dysregulated regeneration during the inflammatory and fibrotic phases. Overall, sustained NLRP3 inflammasome activation led to epithelial remodeling in the distal lung of mice. Moreover, understanding the spatiotemporal profile of dysregulated epithelial repair and regeneration may provide a novel therapeutic strategy for inhalable particle‑related chronic inflammatory and fibrotic lung disease.

Pulmonology for the rhinologist

PURPOSE OF REVIEW

The upper and lower airways are inter-related despite serving different functions and can no longer be considered separately. Rhinologists are becoming increasingly aware of the role the lower airway plays in optimizing outcomes for their patients. This review highlights recent developments in pulmonology that impact rhinologic conditions.

RECENT FINDINGS

The unified airway concept now supports the multidisciplinary management of respiratory and rhinologic pathologies. Biomarkers, biologics and the concept of treatable traits have permitted the development of personalized and precise treatment of the entire respiratory tract. The concept of corticosteroid stewardship, the introduction of steroid sparing agents for the treatment of respiratory diseases and the development of biomarkers, now forces us to be more considerate and precise with oral corticosteroid (OCS) prescribing and to consider reduction regimens. Finally, current research on climate change and vaping will allow us to better educate and prepare our patients to improve adherence and avoid exacerbations to maintain optimal global respiratory health.

SUMMARY

The inter-relatedness of the upper and lower airway has encouraged a multidisciplinary focus in respiratory medicine. More research is required to improve the precision respiratory medicine model, particularly in the realm of biomarkers and endotyping. These developments must also consider the impact of climate change, pollution and toxins for us to provide optimum care for our patients.