The nature of small-airway obstruction in chronic obstructive pulmonary disease

Histopathology of the small airways: Similarities and differences between ageing and COPD

Age-related lung function decline is associated with small airway closure and gas trapping. The mechanisms which cause these changes are not fully understood. It has been suggested that COPD is caused by accelerated ageing. We have investigated pathological changes in the small airways during ageing, and evaluated whether the same or different processes exist in COPD. Histopathology and immunohistochemistry were used to examine small airway remodelling in healthy ageing, and then compare to age matched COPD patients. Ageing was associated with reduced alveolar attachment numbers (rho= -0.4 p = 0.049), increased epithelial area (rho = 0.5 p = 0.01), greater luminal narrowing due to epithelial expansion (rho = 0.5 p = 0.04) and increased alveolar septal neutrophils (rho = 0.6 p = 0.005). Compared to age matched controls, COPD small airways had 31% less alveolar attachments per airway (p = 0.02) and significantly more alveoalr septal neutrophils (p = 0.0007). Increased airway wall thickness was a feature of COPD but was not related to ageing in non-smokers. Alveolar attachment loss, accompanied by alveolar septum neutrophilic inflammation, and increased luminal narrowing due to epithelial expansion are major features of small airway remodelling during ageing. These features can explain the increased small airway narrowing and closure during ageing. Alveolar attachment loss is accelerated in COPD, likely due to increased neutrophilic inflammation.

Mediating effects of gastroesophageal reflux disease and smoking behavior on the relationship between depression and chronic obstructive pulmonary disease: Trans-ethnic Mendelian randomization study

BACKGROUND

This study seeks to elucidate the association between depression and the risk of chronic obstructive pulmonary disease (COPD) by Mendelian randomization (MR) analysis, motivated by prior observational studies indicating a potential link between these conditions.

METHODS

Data from individuals of European (EUR) and East Asian (EAS) ancestries diagnosed with major depressive disorder (MDD) were selected for analysis. The primary method utilized was inverse variance weighted (IVW) method, supplemented by a series of sensitivity analyses and false discovery rate (FDR) corrections. Subsequently, multivariable and mediation MR analyses were conducted to assess the impact of potential confounders and their mediating effects.

RESULTS

IVW revealed a significant causal relationship between MDD and COPD within EUR ancestry (OR 1.425, 95 % CI 1.243-1.633, P = 3.56 × 10-7, PFDR = 2.14 × 10-6). Additionally, replication datasets provided consistent evidence for these causal associations. Multivariable and mediation MR analyses identified gastroesophageal reflux disease (GORD) as a complete mediator (mediation effect: 98.97 %, P = 1.38 × 10-15), while smoking initiation (SI) (26.30 %, 5.54 × 10-9), age of smoking initiation (ASI) (18.73 %, 0.019), and cigarettes per day (CPD) (18.72 %, 0.004) were identified as partial mediators of this causal relationship. No causal association was detected in EAS ancestry, nor was reverse analysis.

CONCLUSIONS

This study established a causal relationship between MDD and COPD risk in EUR ancestry, identifying GORD and smoking as pivotal mediators. Future research involving larger cohorts is essential to validate the generalizability of these findings across other ancestries.

Quantitative CT Scoring for Local COPD Severity

Chronic obstructive pulmonary disease (COPD) is complex, and its course is difficult to predict due to its diverse pathophysiology. Small airway disease (SAD), a key component of COPD and potential target for emerging therapeutics, may be reversible in mild COPD, but left unchecked, may worsen, leading to airway loss and emphysema. The dual nature of SAD complicates clinical management of COPD patients, necessitating more accurate monitoring methods. To meet this need, we developed elastic Parametric Response Mapping (ePRM), a tiered scoring system that classifies local lung volumes by the degree of PRM-derived SAD, normal, and emphysematous tissue. In individuals with or at risk for COPD, we demonstrate that chest CT ePRM can categorize local lung tissue into distinct tiers of disease severity that distinguish between tissue characterized by early reversible SAD and progressive destruction. This level of characterization is crucial to developing personalized treatment strategies for COPD.

Differences in the Inflammatory Response and Corticoid Responsiveness of Human Lung Macrophages and Parenchymal Explants Exposed to Cigarette Smoke Extracts

Smoking is the main cause of chronic obstructive pulmonary disease (COPD) and is associated with corticosteroid resistance. Given the paucity of data on human lung preparations, macrophages (LMs), and parenchymal explants (LPEs) were exposed to cigarette smoke extracts (CSE) in the presence or absence of lipopolysaccharide (LPS). Moreover, LMs and LPEs were treated with budesonide prior exposure to CSE or LPS. The levels of cytokines (TNF-α, IL-6) and chemokines (CCL2, CCL4, CXCL1, CXCL5, and CXCL8) in the supernatants were measured using ELISAs. In LMs, exposure to CSE was not associated with significant difference in the production of cytokines and chemokines, with the notable exception of greater CXCL8 production. The results were generally the same for LPEs. CSE exposure did not potentiate the LPS-induced production of the cytokines and chemokines and even tended to reduce this production in LMs and LPEs. Lastly, CSE exposure inhibited budesonide's anti-inflammatory activity in LMs but not in LPEs. This study extends the data on the CSE inflammatory effects and its inhibition of corticosteroid efficacy in human lung preparations. Our findings question the relevance of these preparations with regard to the long-term toxicity of smoking and the corticosteroid resistance observed in smokers and in patients with COPD.

Effect of inspiratory lung volume on bronchial and arterial dimensions and ratios on chest computed tomography in patients with chronic obstructive pulmonary disease

BACKGROUND

The assessment of bronchus-artery (BA) metrics on chest CT is important for detecting airway abnormalities. It is less clear how BA metrics are dependent on lung volume.

METHODS

CTs were obtained from a COPDGene substudy investigating the impact of radiation dose on lung density. Patients with chronic obstructive pulmonary disease underwent a full-dose and a reduced-dose CT in the same imaging session. CTs were automatically analyzed by measuring diameters of the bronchial outer edge (Bout), bronchial inner wall (Bin), artery (A), and bronchial wall thickness (Bwt) from segmental (G0) and distal generations. BA ratios were computed: Bout/A, Bin/A, Bwt/A, and bronchial wall area/bronchial outer area (Bwa/Boa). The total lung volume of the CT (TLC-CT) was computed. Differences between the volumes between the two CTs were expressed as % of the highest TLC-CT (ΔTLC-CT%). For the BA metrics of each CT, we computed the median of measurements in G1-6. Mixed-effect models were used to investigate the influence of TLC-CT on BA metrics adjusted for dose protocol.

RESULTS

One thousand three hundred nineteen patients with a mean (SD) age of 64.4 (8.7) years were included. Three hundred twenty-nine (124) BA pairs were analyzed per CT. No significant difference was found for TLC-CT in relation to dose (p = 0.17). A ΔTLC-CT% of >10% (found in 121, 9%) led to 0.03 and 0.05 decreases in Bout/A and Bin/A and 0.008 and 0.11 decrease in log (Bwt/A) and log (Bwa/Boa), and a 0.03 increase in Bin and 0.06, 0.12, and 0.04 decrease in Bout, log (Bwt), and log (A) (all p < 0.001).

CONCLUSIONS

Variations in TLC over 10% between time points significantly influence bronchial dimensions, affecting BA metrics. Standardizing volumes is recommended for sensitive tracking of airway disease changes over time.

KEY POINTS

Question Are BA metrics dependent on total lung capacity (TLC), and if so, how? Findings TLC variations over 10% between time points significantly influence bronchial dimensions, affecting BA metrics. Variations below 10% between CT scans have little effect on BA metrics. Clinical relevance Small lung volume differences between chest CTs have little impact on bronchus and artery metrics; it is imperative to standardize chest CT lung volumes to ensure precise diagnosis and monitoring of airway disease.

Monoclonal Antibodies for the Treatment of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common and complex disease characterized by persistent airflow limitation and the presence of exacerbations, resulting in significant morbidity and mortality. Although the pathogenesis of COPD is multifactorial, airway inflammation plays a significant role in disease progression. Despite the advantages of non-pharmaceutical and pharmaceutical interventions that have significantly improved the symptom burden and exacerbation frequency in COPD, there is a lack of disease-modifying therapies that target the underlying disease mechanisms. Monoclonal antibodies (mAbs), a drug class that has improved treatment in severe asthma by blocking mediators of the type 2 (Th2) and allergic inflammatory cascades, are currently under investigation for their efficacy in COPD. Our review summarizes the evidence for the use of monoclonal antibodies in COPD and discusses current limitations and promising advances. Although targeting Th1 inflammation has failed to improve COPD outcomes, recent clinical trials have shown beneficial effects of monoclonal antibodies targeting Th2 inflammation, providing evidence for a personalized approach in COPD treatment.

Identification and validation of USP15 and CUL2 as ubiquitination related biomarker in chronic obstructive pulmonary disease

PURPOSE

Ubiquitination is one of the important epigenetic modifications, influencing the development of various diseases. The objective of this study is to investigate the ubiquitination related genes in chronic obstructive pulmonary disease (COPD).

METHODS

The gene microarray dataset from COPD patients and ubiquitination related genes were analyzed. Venn diagram analysis was used to intersect differentially expressed genes and ubiquitination related genes. The functional enrichment analysis of Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) were performed on differentially expressed ubiquitination related genes. Finally, we confirmed the expression of hub genes through qPCR and western blot experiments in clinical COPD patients and cell lines.

RESULTS

We identified 2,932 differentially expressed genes and 96 differentially expressed ubiquitination related genes. GO analysis indicated that the differentially expressed ubiquitination related genes were mainly enriched in post-translational protein modification and ubiquitin ligase complex. KEGG analysis showed that ubiquitination related genes were mainly involved in ubiquitin mediated proteolysis and TNF signaling pathway. GSEA analysis suggested that some hub genes are involved in allograft rejection, IL6/JAK/STAT3 signaling and inflammatory response. Our qPCR and western blot experimental results indicate that the expression of USP15 and CUL2 is higher in COPD group compared to the control group, consistent with the bioinformatics analysis.

CONCLUSION

Our bioinformatics analysis and experimental results suggest that USP15 and CUL2 may contribute to the progression of COPD through ubiquitination modification. To our knowledge, this is the first study to demonstrate the involvement of USP15 and CUL2 in COPD. Our results may provide new insights into the diagnosis and treatment of COPD.

scRNA-seq and scATAC-seq analyses highlight the role of TNF signaling pathway in chronic obstructive pulmonary disease model mice

Chronic obstructive pulmonary disease (COPD) is a prevalent and progressive form of respiratory disease in which patients exhibit persistent respiratory damage affecting the alveoli and/or airway due to exposure to toxic gases or particulate matter. C57BL/6 mice were exposed to cigarette smoke and lipopolysaccharide to establish a COPD model mice, followed by scATAC (Assay for Transposase Accessible Chromatin) sequencing and scRNA sequencing of lung tissue samples. The resultant data revealed consistent findings between scATAC-seq and scRNA-seq regarding cell types, differentially expressed genes, and signaling pathways in COPD model mice. Tumor necrosis factor (TNF) signaling pathway enrichment was evident in the scRNA-seq and scATAC-seq datasets, with similar trends in monocytes/macrophages, dendritic cells, and B cells. In COPD model mice, significant tumor necrosis factor receptor 1 (TNFR1) upregulation and high levels of activity related to cellular communication were observed, and significant increases in Il1b, Csf1, and Bcl3 site accessibility were evident in cells. These findings suggest that the TNF signaling pathway maybe associated with COPD.

Type 2 inflammation, a common denominator in chronic airway disease?

PURPOSE OF REVIEW

This review addresses the growing understanding that a specific subset of patients with a respiratory disease, including asthma, chronic obstructive pulmonary disease (COPD), or bronchiectasis may have one thing in common: type 2 inflammation. In the era of personalized medicine, we need to refine clinical markers combined with molecular and cellular endotyping to improve patient outcomes.

RECENT FINDINGS

Recent literature reveals that type 2 markers such as blood eosinophils, fractional exhaled nitric oxide (FeNO), and immunglobulin E (IgE), can provide valuable insights into disease progression, exacerbation risk, and treatment response, but their stability remains to be investigated. Treating asthma and COPD patients with biologics to target IL-4/IL-13, IL-5, and alarmins have shown potential, although efficacy varied. In bronchiectasis, a subset of patients with type 2 inflammation may benefit from corticosteroid therapy, despite broader concerns regarding its use.

SUMMARY

This underscores the importance of improved disease endotyping to better characterize patients who may benefit from targeted therapies. In clinical practice, personalized treatment based on inflammatory profiles has been shown to improve outcomes in heterogeneous lung diseases. Future research needs to focus on validating reliable biomarkers and optimizing clinical trial designs to advance therapeutic strategies in respiratory diseases.

Airway and cardiovascular remodeling in chronic obstructive pulmonary disease (COPD) as a target for transient receptor potential ankyrin 1 (TRPA1) channel modulators

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, which leads to airway remodeling (AR). AR refers to various structural changes occurring in the airway wall, resulting in thickening, and narrowing of the airways. Apart from airways, and lung tissue, pulmonary vasculature also undergoes remodeling. Thus, the pressure in vascular bed is increased, leading to pulmonary hypertension and further right and left ventricle hypertrophy, as well as myocardial fibrosis. Currently, there is lack of effective treatment directly targeting airway and cardiovascular remodeling in the course of COPD. Due to a lot of research showing involvement of transient receptor potential ankyrin 1 (TRPA1) in respiratory disorders, it seems reasonable to consider this ion channel as a molecular target in treatment of remodeling consequences of COPD. The aim of this review is to summarize current knowledge of its role in this case and to identify areas requiring further research. Moreover, we provide few patented structures intended to treat chronic respiratory diseases, which may be worth investigating in the context of airway remodeling.

Cyclic nucleotide phosphodiesterases as drug targets

Cyclic nucleotides are synthesized by adenylyl and/or guanylyl cyclase, and downstream of this synthesis, the cyclic nucleotide phosphodiesterase families (PDEs) specifically hydrolyze cyclic nucleotides. PDEs control cyclic adenosine-3',5'monophosphate (cAMP) and cyclic guanosine-3',5'-monophosphate (cGMP) intracellular levels by mediating their quick return to the basal steady state levels. This often takes place in subcellular nanodomains. Thus, PDEs govern short-term protein phosphorylation, long-term protein expression, and even epigenetic mechanisms by modulating cyclic nucleotide levels. Consequently, their involvement in both health and disease is extensively investigated. PDE inhibition has emerged as a promising clinical intervention method, with ongoing developments aiming to enhance its efficacy and applicability. In this comprehensive review, we extensively look into the intricate landscape of PDEs biochemistry, exploring their diverse roles in various tissues. Furthermore, we outline the underlying mechanisms of PDEs in different pathophysiological conditions. Additionally, we review the application of PDE inhibition in related diseases, shedding light on current advancements and future prospects for clinical intervention. SIGNIFICANCE STATEMENT: Regulating PDEs is a critical checkpoint for numerous (patho)physiological conditions. However, despite the development of several PDE inhibitors aimed at controlling overactivated PDEs, their applicability in clinical settings poses challenges. In this context, our focus is on pharmacodynamics and the structure activity of PDEs, aiming to illustrate how selectivity and efficacy can be optimized. Additionally, this review points to current preclinical and clinical evidence that depicts various optimization efforts and indications.

Lung function decline and incidence of chronic obstructive pulmonary disease in participants with spirometry-defined small airway dysfunction: a 15-year prospective cohort study in China

BACKGROUND

Small airway dysfunction (SAD) is common but little is known about the longitudinal prognosis of spirometry-defined SAD. Therefore, we aimed to evaluate the risk of lung function decline and incident chronic obstructive pulmonary disease (COPD) of spirometry-defined SAD.

METHODS

It was a population-based prospective cohort study conducted in Guangdong, China. Participants were enrolled in the years 2002, 2008, 2012, 2017, and 2019, and those who completed baseline demographic data, a standardized epidemiological questionnaire for COPD, and spirometry were included. Follow-up visits were conducted every three years after enrolment, with a maximum follow-up time of 15 years and a minimum follow-up time of 3 years. Spirometry-defined SAD was defined as having at least two out of three parameters (maximal mid-expiratory flow, forced expiratory flow 50%, and forced expiratory flow 75%) below 65% of the predicted value. Non-obstructive SAD and obstructive SAD were further differentiated based on the presence of airflow obstruction (forced expiratory volume in one second [FEV1]/forced vital capacity [FVC] < 0.70). Pre- and post-bronchodilator spirometry measurements were analyzed separately.

RESULTS

Pre-bronchodilator spirometry dataset included 4680 participants (mean age 55.3 [10.8] years, 2194 [46.9%] males). Participants with pre-bronchodilator SAD had a significantly faster annual decline of FEV1 % of predicted value (0.31 ± 0.05 vs. 0.20 ± 0.03 %/year; difference: 0.12 [95% confidence interval: 0.01-0.23]; P = 0.023), FVC, and FVC % of predicted value compared to those without pre-bronchodilator SAD. The annual decline of lung function in participants with pre-bronchodilator non-obstructive SAD was not significantly different from that in pre-bronchodilator healthy controls, but they were more likely to progress to spirometry-defined COPD (adjusted hazard ratio: 2.92 [95% confidence interval: 2.28-3.76], P < 0.001). Post-bronchodilator spirometry dataset yielded similar results.

CONCLUSIONS

Individuals with spirometry-defined SAD have a faster decline in lung function compared to those without SAD, and non-obstructive SAD is more likely to progress to spirometry-defined COPD.

TRIAL REGISTRATION

Chinese Clinical Trials Registration ChiCTR1900024643. Registered on 19 July 2019.

Classification of collagen remodeling in asthma using second-harmonic generation imaging, supervised machine learning and texture-based analysis

Airway remodeling is present in all stages of asthma severity and has been linked to reduced lung function, airway hyperresponsiveness and increased deposition of fibrillar collagens. Traditional histological staining methods used to visualize the fibrotic response are poorly suited to capture the morphological traits of extracellular matrix (ECM) proteins in their native state, hindering our understanding of disease pathology. Conversely, second harmonic generation (SHG), provides label-free, high-resolution visualization of fibrillar collagen; a primary ECM protein contributing to the loss of asthmatic lung elasticity. From a cohort of 13 human lung donors, SHG-imaged collagen belonging to non-asthmatic (control) and asthmatic donors was evaluated through a custom textural classification pipeline. Integrated with supervised machine learning, the pipeline enables the precise quantification and characterization of collagen, delineating amongst control and remodeled airways. Collagen distribution is quantified and characterized using 80 textural features belonging to the Gray Level Cooccurrence Matrix (GLCM), Gray Level Size Zone Matrix (GLSZM), Gray Level Run Length Matrix (GLRLM), Gray Level Dependence Matrix (GLDM) and Neighboring Gray Tone Difference Matrix (NGTDM). To denote an accurate subset of features reflective of fibrillar collagen formation; filter, wrapper, embedded and novel statistical methods were applied as feature refinement. Textural feature subsets of high predictor importance trained a support vector machine model, achieving an AUC-ROC of 94% ± 0.0001 in the classification of remodeled airway collagen vs. control lung tissue. Combined with detailed texture analysis and supervised ML, we demonstrate that morphological variation amongst remodeled SHG-imaged collagen in lung tissue can be successfully characterized.

Role of Regulatory T Cells in Pulmonary Ageing and COPD Development

Chronic obstructive pulmonary disease (COPD) is recognized as a long-term inflammatory lung condition, predominantly resulting from smoking tobacco. While all smokers exhibit some level of pulmonary inflammation, only about 15-20% go on to develop significant COPD, indicating that specific individual factors may enhance these inflammatory responses and contribute to the disease's progression. T regulatory cell (Treg) activity is crucial in mediating pulmonary inflammation in COPD. With accumulating evidence supporting the autoimmune characteristics of COPD, there has been an increasing focus on the role Treg cells play in the disease's initiation and development. This article aims to review the existing literature regarding Treg cells and their influence on COPD pathogenesis and lung ageing. Treg-mediated suppression is a critical mechanism in the negative regulation of immune-related inflammation, which is significant in various disorders, including autoimmunity, allergies, infections (both acute and chronic), and cancer. The lungs of ageing individuals often resemble those affected by COPD, leading to the perception of COPD as a condition that accelerates lung ageing. Changes in Treg cells with age correspond to decreased adaptive immune responses and a higher likelihood of immune-related disorders. The increased presence of Treg cells in older adults may help explain several immunological conditions commonly associated with ageing, which include malignancies, infections, and COPD.

Computational fluid dynamics of small airway disease in chronic obstructive pulmonary disease

BACKGROUND

Small airways (<2 mm diameter) are major sites of airflow obstruction in chronic obstructive pulmonary disease (COPD). This study aimed to quantify the impact of small airway disease, characterized by narrowing, occlusion, and obliteration, on airflow parameters in smokers and end-stage patients with COPDs.

METHODS

We performed computational fluid dynamics (CFD) simulations of inspiratory airflow in three lung groups: control non-used donor lungs (no smoking/emphysema history), non-used donor lungs with a smoking history and emphysema, and explanted end-stage COPD lungs. Each group included four lungs, with two tissue cylinders. Micro-CT-scanned small airways were segmented into 3D models for CFD simulations to quantify pressure, resistance, and shear stress. CFD results were benchmarked against simplified linear and Weibel models.

FINDINGS

CFD simulations showed higher pressures in COPD vs. controls (p = 0.0091) and smokers (p = 0.015), along with increased resistance (p = 0.0057 vs. controls; p = 0.0083 vs. smokers) and up to a tenfold rise in shear stress (p = 0.010 vs. controls). Narrowing and occlusion were shown to independently increase pressure, resistance, and shear stress, which were validated through segmentation corrections. Pressures and resistance assessed with simplified models were up to seven-fold higher for smokers and even 72 higher for COPD compared with CFD values.

INTERPRETATION

These findings show that increased airflow parameters can explain the association between small airway disease and airflow limitation in COPD, underscoring small airway vulnerability. Additionally, they highlight the limitations of theoretical models in accurately capturing small airway disease.

FUNDING

Supported by the KU Leuven (C16/19/005).

Effects of different degrees of anthracosis on pleural structure: A preliminary exploratory study

BACKGROUND

Pleural anthracosis (PA) appears as superficial black discoloration or scattered focal black spots on the surface of the pleura. Few studies have investigated the relationship between PA and changes in pleural structure. The aim of this study is to perform a detailed morphometric characterization of pleura in patients with different degrees of PA at both macroscopic and microscopic levels.

METHODS

Preoperative, intraoperative, and postoperative data were collected for all patients. Lung tissue (far away from the tumor) was obtained from patients with pulmonary nodules who required surgical treatment. According to different degrees of PA, the pleura were classified into four degrees. In addition to using grade data, we also calculated the ratio of PA. Slices were stained with Hematoxylin-eosin (HE) and D2-40 to obtain the results of pleural structures.

RESULTS

We prospectively evaluated 48 subjects between March 12, 2024 and August 17, 2024. There was no significant difference in PA levels between people living in urban and rural areas (P = 0.32). However, the proportion of rural population in patients with PA level 3 was 2.6 times that of urban population. Patients who were male demonstrated significantly higher level of PA (P = 0.01). With the increase of the smoking index, the patients with PA levels increased. PA levels increased with age (P = 0.02). With the decrease of the FEV1/FVC, the patients with PA levels also increased (P = 0.03), and the patients with PA ratio also increased (P = 0.007). With the continuous improvement of PA ratio and upgrading of PA level, the pleural thickness continued to decrease(R = -0.75, P < 0.01), the number of subpleural lymphatic vessels (SLVs) increased (P < 0.01), cross-sectional area of SLVs increased (P < 0.01), length of SLVs increased (P < 0.01), and SLVs density increased (P < 0.01).

CONCLUSIONS

The current study demonstrated that the proportion of PA is negatively correlated with pleural thickness and positively correlated with the number of SLVs, cross-sectional area of SLVs, length of SLVs, and SLVs density. This study provides us with new evidence for the subpleural lymphatic metastasis pathways.

Nasal production of IL-26 involving T cells in smokers with and without chronic obstructive pulmonary disease

BACKGROUND

Novel specific therapy in chronic obstructive pulmonary disease (COPD) will require accessible targets for endotyping to identify responsive patients. It is therefore of interest that IL-26 in the bronchoalveolar space is enhanced and associates with bronchoalveolar pathology among long-term smokers (LTS) with and without COPD.

OBJECTIVE

We determined whether IL-26 in the nasal cavity can be produced by T cells and associates with bronchoalveolar pathology and clinical symptoms in LTS with and without COPD.

METHODS

We characterized LTS with and without COPD plus healthy nonsmokers by radiology, spirometry, modified Medical Research Council scale, and St George Respiratory Questionnaire. We determined extracellular IL-26 concentrations (via ELISA) in nasal (NAL) and bronchoalveolar lavage (BAL) samples, BAL neutrophil counts, and NAL IL-26+ T-cell expression (via flow cytometry).

RESULTS

The NAL IL-26 concentrations were higher in LTS with COPD than in healthy nonsmokers. These enhanced IL-26 concentrations displayed a positive correlation with forced expiratory volume in 1 second/forced vital capacity ratio. The IL-26 protein was expressed in CD4+ and CD8+ T cells, but only a small portion of these cells coexpressed IL-15, IL-17A, or IL-22 in LTS with COPD. In this group, IL-26+ CD3+ T cells displayed a negative correlation with forced expiratory volume in 1 second, as did with extracellular NAL IL-26 concentrations. The relative mean fluorescence intensity for CD8+ T cells displayed a negative correlation with modified Medical Research Council and St George Respiratory Questionnaire score.

CONCLUSION

In the nasal cavity, IL-26 can be produced by local T cells. This IL-26 reflects bronchoalveolar pathology and clinical symptoms, thereby constituting an accessible target with potential for clinically relevant endotyping in COPD.

Structure and function relationships of mucociliary clearance in human and rat airways

Mucociliary clearance is a vital defense mechanism of the human airways, protecting against harmful particles and infections. When this process fails, it contributes to respiratory diseases like chronic obstructive pulmonary disease (COPD) and asthma. While advances in single-cell transcriptomics have revealed the complexity of airway composition, much of what we know about how airway structure impacts clearance relies on animal studies. This limits our ability to create accurate human-based models of airway diseases. Here we show that the airways in female rats and in humans exhibit species-specific differences in the distribution of ciliated and secretory cells as well as in ciliary beat, resulting in significantly higher clearance effectiveness in humans. We further reveal that standard lab-grown cultures exhibit lower clearance effectiveness compared to human airways, and we identify the underlying structural differences. By combining diverse experiments and physics-based modeling, we establish universal benchmarks to assess human airway function, interpret preclinical models, and better understand disease-specific impairments in mucociliary clearance.

Effective-Component Compatibility of Bufei Yishen Formula (ECC-BYF) III Inhibits Mucus Hypersecretion by BEAS-2B Cells via miR-146a-5p-Mediated Regulation of the EGFR/MEK/ERK Pathway

Purpose

To explore the role of the miR-146a-5p-mediated regulation of the EGFR/MEK/ERK pathway in the effect of effective-component compatibility of Bufei Yishen Formula III (ECC-BYF III) on ameliorating mucus hypersecretion by bronchial epithelial cells (BEAS-2B cells).

Methods

BEAS-2B cells exposed to cigarette smoke extract (CSE) were used to establish a mucus hypersecretion model of BEAS-2B cells. The optimal intervention concentration of ECC-BYF III was screened by CCK-8, qRT-PCR and ELISA, the effects of ECC-BYF III on MUC5AC, MUC5B, IL-4, IL-8, TNF-α, IL-1α, miR-146a-5p and EGFR/MEK/ERK pathway expression were assessed. Furthermore, dual luciferase reporter gene was used to verify the relationship between miR-146a-5p and EGFR/MEK/ERK, and to observe the effect of down-regulating miR-146a-5p on ECC-BYF III ameliorating mucus hypersecretion and EGFR/MEK/ERK pathway.

Results

ECC-BYF III reduced the expression of MUC5AC and MUC5B, decreased the mRNA expression of IL-1α, IL-8 and TNF-α, increased the mRNA expression of IL-4, and decreased the protein expression of TNF-α. Moreover, ECC-BYF III ameliorated CSE induced mucus hypersecretion in BEAS-2B cells through EGFR/MEK/ERK pathway. Finally, our results indicated that ECC-BYF III ameliorated the model by targeting miR-146a-5p and downregulating the EGFR/MEK/ERK pathway.

Conclusion

ECC-BYF III can ameliorate CSE induced mucus hypersecretion by BEAS-2B cells and reduce the inflammatory response. The underlying mechanism may be related to the regulation of miR-146a-5p and the EGFR/MEK/ERK pathway. ECC-BYF III can inhibit activation of the EGFR/MEK/ERK pathway by upregulating the expression of miR-146a-5p, thereby ameliorating mucus hypersecretion by BEAS-2B cells.

Relationship between systemic immune response index (SIRI) and COPD: a cross-sectional study based on NHANES 2007-2012

Although the link between inflammation and chronic obstructive pulmonary disease (COPD) is increasingly recognized, the correlation between systemic immune response index (SIRI), a novel marker of inflammation, and COPD is unknown. This cross-sectional study used data from patients with complete lung function in NHANES 2007-2012 to explore the relationship between SIRI and COPD. We performed a series of statistical analyses on a total of 5056 participants, including multiple linear regression, smoothed curve fitting, ROC curve analysis, and subgroup analysis. In the fully corrected model, the logistic multiple regression showed that SIRI was associated with a high risk of COPD (OR1.350, 95% CI:1.220,1.493). The ROC curve showed that SIRI (AUC = 0.596) was significantly more efficient than other inflammatory factors in predicting COPD. Smoothed curve fit effect and threshold effect analyses showed a linear correlation between SIRI COPD prevalence, and subgroup analyses showed that the effect of SIRI on COPD was more pronounced in still smokers (OR 1.58, 95% CI: 1.34, 1.86) versus men (OR 1.62, 95% CI: 1.44, 1.83). The results of the interaction test provide evidence supporting SIRI as an independent risk factor for COPD.

Can the single-breath alveolar volume be adjusted to estimate true total lung capacity?

Background

Total lung capacity (TLC) measured with single-breath gas diffusion (TLCsb) is systematically lower than TLC measured with whole-body plethysmography (TLCwbp) especially in patients with obstructive defects. We aimed to develop and validate a regression correction equation to reduce the discrepancy between the two measurements of TLC. Second, we compared the ability to detect restriction (reduced TLC) from adjusted TLC measured by single-breath (TLCsbadj) with gold standard TLCwbp.

Methods

Lung function data from 800 consecutive patients were analysed with multivariable linear regression. A group of 530 were included for model development, and 270 were used for model validation.

Results

TLCsb was found to be on average 1.1 L lower than TLCwbp (p < 0.001). This difference increased with degree of airway obstruction. After adjustment TLCsbadj did not significantly differ from TLCwbp in obstructive and mixed obstructive-restrictive subjects. TLCsbadj had a sensitivity of 70% and a specificity of 99% to predict restriction on an individual basis, with a 95% confidence interval (CI) of [-19.6%; 17.7%] percentage when comparing adjusted values of TLCsb with the true TLCwbp value.

Conclusions

After adjustment TLCsb was no longer significantly underestimated in obstructive and mixed restrictive-obstructive groups compared to TLCwbp. The adjustment can be used on individual subjects to estimate restriction via the TLCsb, thereby making the single-breath gas diffusion method a more valid alternative than without adjustment, when compared with the gold standard whole-body plethysmography to measure TLC.

Εosinophilic Chronic Obstructive Pulmonary Disease. What Do We Know So Far?

The latest advances in asthma treatment have highlighted the significance of eosinophilia and the possible role of some pro-eosinophilic mediators, like interleukins (IL) IL-5, IL-4/IL-13, and IL-33 in the disease's pathogenesis. Considering that a subgroup of patients with chronic obstructive pulmonary disease (COPD) may have blood eosinophilia akin to that seen in asthma, numerous studies in the last decade have suggested that eosinophilic COPD is a separate entity. While the exact role of blood eosinophils in the pathophysiology of COPD remains unclear, eosinophilia seems to increase the effectiveness of corticosteroid therapy. Currently, monoclonal antibodies targeting the interleukins (IL-5, IL-4, IL-13, and IL-33) or their receptors are being investigated in patients with COPD belonging in T2-high endotype. This review focuses on the mechanisms of eosinophilia in COPD, the effects of eosinophilia on disease outcome, and examines the most recent data on the use of peripheral blood eosinophilia in treating patients with COPD. Finally, we emphasize the current implication of monoclonal antibodies in COPD in the context of eosinophilic airway inflammation.

Mucus Plugs as Precursors to Exacerbation and Lung Function Decline in COPD Patients

BACKGROUND

Mucus plugs identified through chest computed tomography (CT) scans have emerged as potential prognostic factors in chronic obstructive pulmonary disease (COPD). This 5-year longitudinal study investigated their impact on exacerbations and FEV1 decline.

METHODS

COPD patients with baseline chest CT and spirometric assessments were categorized based on mucus plug presence. Propensity-score matching yielded balanced groups. Exacerbation rates, time to exacerbation events, hazard ratio (HR) for exacerbations, and annual rates of FEV1 decline were evaluated. Sensitivity analysis was performed with stratification according to mucus plug scores of 0, 1-2, and ≥3.

RESULTS

Among 623 eligible patients, the mucus plug group was 44.3%. Through 1:1 propensity-score matching, each group was comprised of 187 individuals with balanced covariates. The mucus plug group showed higher rates of moderate-to-severe (0.51/year vs. 0.58/year, P=0.035), severe exacerbations (0.21/year vs. 0.24/year, P=0.032), and non-eosinophilic exacerbations (0.45/year vs. 0.52/year, P=0.008). Mucus plugs were associated with increased hazard of moderate-to-severe (adjusted HR=1.502 [95% CI 1.116-2.020]), severe (adjusted HR=2.106 [95% CI, 1.429-3.103]), and non-eosinophilic exacerbations (adjusted HR=1.551 [95% CI, 1.132-2.125]). Annual FEV1 decline was accelerated in the mucus plug group (β-coefficient=-62 [95% CI, -120 to -5], P=0.035). Sensitivity analysis showed higher risk of exacerbations and accelerated FEV1 decline in mucus plug score ≥3 compared to score 0.

CONCLUSIONS

Mucus plugs are associated with increased risks of exacerbations, particularly non-eosinophilic, and accelerated FEV1 declines over 5 years. Our study identified the potential prognostic value of mucus plugs on future exacerbation risks and lung function decline trajectories.

Adherence to Inhalation Therapy Among COPD Patients: A Cross-Sectional Study in a Tertiary Hospital in Quito, Ecuador

Background

Chronic Obstructive Pulmonary Disease (COPD), the third leading cause of death globally, poses a significant public health burden. Despite its high prevalence, underdiagnosis and poor treatment adherence remain major challenges, contributing to increased hospitalization and mortality.

Purpose

This study aimed to assess adherence to inhalation therapy among COPD patients treated at a specialty hospital in Quito, Ecuador.

Patients and Methods

A cross-sectional study was conducted on 85 patients diagnosed with COPD at a tertiary hospital in Quito. Data was collected through face-to-face surveys, utilizing the TAI-10 questionnaire to assess treatment adherence, along with demographic and clinical characteristics of the patients.

Results

Among the participants, 34.1% demonstrated good adherence to inhalation therapy, while 32.9% exhibited intermediate adherence, and 32.9% were non-adherent. The majority were older adults aged ≥76 years (67.1%) with a high prevalence of comorbidities (91.8%), particularly hypertension (58.8%). Non-adherence was primarily associated with forgetfulness and financial constraints. Higher BMI was significantly linked to better adherence, with obese patients showing higher odds of intermediate (OR=7.228, 95% CI 1.866-27.996) and good adherence (OR=9.966, 95% CI 2.538-39.139).

Conclusion

Approximately one-third of COPD patients in Ecuador demonstrate good adherence to inhalation therapy, while similar proportions show intermediate or poor adherence. Predominantly older adults and retirees with comorbidities, the population identified forgetfulness and financial constraints as key barriers. These findings emphasize the need for enhanced patient education, regular follow-ups, and tailored support for vulnerable groups.

Structure and Function Relationships of Mucociliary Clearance in Human and Rat Airways

Mucociliary clearance is a vital defense mechanism of the human airways, protecting against harmful particles and infections. When this process fails, it contributes to respiratory diseases like chronic obstructive pulmonary disease (COPD) and asthma. While advances in single-cell transcriptomics have revealed the complexity of airway composition, much of what we know about how airway structure impacts clearance relies on animal studies. This limits our ability to create accurate human-based models of airway diseases. Here we show that the airways in female rats and in humans exhibit species-specific differences in the distribution of ciliated and secretory cells as well as in ciliary beat, resulting in significantly higher clearance effectiveness in humans. We further reveal that standard lab-grown cultures exhibit lower clearance effectiveness compared to human airways, and we identify the underlying structural differences. By combining diverse experiments and physics-based modeling, we establish universal benchmarks to assess human airway function, interpret preclinical models, and better understand disease-specific impairments in mucociliary clearance.

Bronchus-associated lymphoid tissue in lung transplantation: a facilitator of rejection or regulator of tolerance?

The role of bronchus-associated lymphoid tissue (BALT) in the regulation of immune responses to transplanted lungs remains an area of interest and controversy. Early studies in a rat pulmonary transplant model suggested BALT may accelerate rejection of grafts by inducing a local and systemic inflammatory response. Such observations were corroborated in intrapulmonary tracheal transplant models in the rat. While some human studies have described the presence of BALT in grafts that have been chronically rejected, others did not observe an association between induction of BALT and adverse outcomes. More recent investigations have found that BALT, enriched in immunoregulatory cell populations, is induced in tolerant mouse lung allografts, suggesting that such structures may be protective against rejection. Thus, the role of BALT in lung transplantation biology is complex. Insights gained from studies that focus on the role of BALT in lung transplantation may be harnessed to develop new therapies.

Pulmonary function tests: an integrated approach to interpreting results in the search for treatable traits

INTRODUCTION

Technological advances have led to the proliferation of lung function assessment techniques beyond spirometry in most countries. At the same time, new knowledge of respiratory physiology has allowed an expansion of lung function parameters, requiring an integrated approach to interpreting results.

AREAS COVERED

This review addresses the major pulmonary function tests (PFTs) used in clinical practice, new concepts regarding reference values, and reformulations of terminology for defining standards of lung function impairment. It highlights the complexities and nuances inherent in the interpretation of PFT parameters, particularly in light of recent updates from the European Respiratory Society/American Thoracic Society.

EXPERT OPINION

In a new paradigm, PFTs should be used to classify the pathophysiology of treatable traits rather than to diagnose respiratory disease, given the considerable variation in the clinical patterns of PFTs. It is necessary to look not only at lung mechanics but also at lung volume, gas transfer, and small airway involvement to capture as much information as possible. In this context, it is also important to understand that racial/ethnic differences in lung function are not due to biological differences but may reflect socioeconomic status and represent health disparities.

Airways Abnormalities in a Prospective Cohort of Patients With Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) affects roughly 1% of the population and commonly involves the lungs. Of lung involvement in RA, interstitial lung disease (ILD) is well known; however, airways disease in RA is relatively understudied.

RESEARCH QUESTION

What are the baseline airways abnormalities in a prospective cohort of patients with RA based on pulmonary function testing (PFT) results, high-resolution CT (HRCT) scans, and computational imaging analysis and are there associations between these abnormalities and respiratory symptoms?

STUDY DESIGN AND METHODS

In this single-center study, 188 patients with RA without a clinical diagnosis of ILD underwent HRCT imaging and PFT. Radiologists assessed HRCT scans for airway abnormalities. Computational imaging via VIDA Vision software and in-house quantitative CT imaging analysis was applied to 147 HRCT scans to quantify airway abnormalities.

RESULTS

Airways obstruction (FEV1 to FVC ratio < 0.7) was present in 20.7% of patients and was associated with older age, male sex, and higher smoking rate. Radiologists identified airway abnormalities in 61% of patients: 55% had bronchial wall thickening, 12% had bronchiectasis, and 5% had mosaic attenuation. These airways findings were associated with older age; male sex; lower FEV1, FVC, and FEV1 to FVC ratio; and higher rates of rheumatoid factor positivity. Prespecified quantitative CT scan metrics (wall thickening percentage and emphysema percentage) correlated with obstruction in PFT results and more severe respiratory symptoms, including shortness of breath and cough.

INTERPRETATION

High rates of airways abnormalities were found in this prospective RA cohort based on three methods of detection. Significant associations were identified between quantitative CT scan measures and respiratory symptoms. Airways disease may be an underrecognized extra-articular manifestation of RA and quantitative CT imaging may be a sensitive method to detect the clinical impact on respiratory symptoms.

Serum Soluble Urokinase-Type Plasminogen Activator Receptor: A Promising Biomarker for Stable Chronic Obstructive Pulmonary Disease Patients

Background Chronic obstructive pulmonary disease (COPD) is a condition in which airflow limitation becomes irreversible over time, often resulting from long-term exposure to environmental pollutants, harmful particles, smoke, and biomass fuel. Beyond FEV1, identifying a more specific biomarker to predict COPD progression remains a challenge. Soluble urokinase-type plasminogen activator receptor (suPAR) expression increases in the respiratory epithelial cells of COPD patients. This study aimed to evaluate serum suPAR levels across different grades of stable COPD patients. Methods Two hundred stable COPD patients (148 males and 52 females) were recruited after obtaining informed consent. Blood samples were collected, and serum suPAR levels were measured in all participants. Results Serum suPAR levels were elevated in COPD patients at Global Initiative for Obstructive Lung Disease (GOLD) stages IV and III (6.38 ± 0.05 ng/ml and 5.82 ± 0.18 ng/ml, respectively) compared to those at GOLD stages II and I (5.15 ± 0.25 ng/ml and 4.17 ± 0.29 ng/ml). A one-way ANOVA confirmed that the differences between groups were statistically significant (F = 428.83, p < 0.001). Conclusions This study suggests that serum suPAR levels can serve as a diagnostic marker for COPD. As low-grade pulmonary inflammation increases with disease severity, suPAR levels also rise. Additionally, this marker may be useful for monitoring the prognosis of stable COPD and assessing treatment response.

Glypican-3 is a key tuner of the Hedgehog pathway in COPD

Hedgehog (HH) pathway is involved in pulmonary development and lung homeostasis. It orchestrates airway epithelial cell (AEC) differentiation and contributes to respiratory pathogenesis. The core elements Gli2, Smo, and Shh were found altered in the bronchial epithelium of patients with chronic obstructive pulmonary disease (COPD). Here, we investigated the co-receptors to fully decipher the complex machinery of airway HH pathway activation in health and COPD. The core elements and co-receptors of HH signalling were investigated in lung cell populations using single-cell RNAseq analysis. The transcript levels of the principal co-receptor GPC3 were investigated on public RNAseq datasets and by RT-qPCR. The localisation of GPC3 was evaluated through immunofluorescent stainings on isolated bronchial AEC and tissues from non-COPD and COPD patients. GPC3 pharmacological modulation was achieved with Codrituzumab during AEC differentiation. We demonstrated that the core elements were not abundant in pulmonary cell populations. Focusing on co-receptors, GPC3 was the most expressed transcript in tracheobronchial epithelial cells. The decrease in GPC3 transcript levels correlated with the severity of airway obstrution in COPD patients. Finally, interfering with GPC3 signalling during AEC differentiation induced downregulation of the HH pathway attested by a decrease of Gli2 leading to reduced ciliogenesis and altered mucin production. GPC3 appears as a crucial co-receptor for the HH pathway in the respiratory context. The modulation of GPC3 may represent a novel experimental strategy to tune HH signalling in therapeutic perspectives.

Prospects of neutrophilic implications against pathobiology of chronic obstructive pulmonary disease: Pharmacological insights and technological advances

Chronic obstructive pulmonary disease (COPD) is a prevalent chronic inflammatory condition that affects the lungs globally. A key feature of this inflammatory response is the migration and aggregation of polymorphonuclear neutrophils (PMNs). The presence of neutrophilic inflammation within the airways is as distinguishing characteristic of COPD. As research advances, PMNs and their products emerge as central players in the airway inflammatory cascade of COPD patients. Their involvement in phagocytosis, degranulation, and the formation of neutrophil extracellular traps (NETs) significantly contributes to the pathogenesis of COPD. Moreover, studies have shown that excessive biological activities of neutrophils in the lungs can result in airway epithelial injury, emphysema, and mucus hypersecretion. Currently, there is growing empirical support for the moderate targeting neutrophils in the clinical management of COPD. This article delves into the pivotal role of neutrophils in COPD, emphasizing the urgency for novel therapeutic approaches that specifically target neutrophils. Additionally, it explores the potential of utilizing single-cell RNA sequencing to further investigate neutrophils and relevant risk genes as potential biomarkers for COPD treatment. By elucidating these mechanisms, this review aims to pave the way for future strategies to modulate neutrophil function, thereby addressing the pressing need for more effective COPD therapies.

Peripheral Blood NMLR Can Predict 5-Year All-Cause Mortality in Patients with Chronic Obstructive Pulmonary Disease

Background

Chronic obstructive pulmonary disease (COPD) is characterized by pulmonary and systemic inflammation. The peripheral blood (neutrophil + monocyte)/lymphocyte ratio (NMLR) can predict the clinical outcomes of several inflammatory diseases. However, its prognostic value in COPD remains unknown.

Methods

This retrospective study included 870 patients with COPD due to acute exacerbation, and the 5-year all-cause mortality of these patients was recorded. The Kaplan-Meier method was used to compare the mortality risk of these patients according to their NMLR value. Multivariable COX hazard regression and restricted cubic spline model were used to assess the relationship between the NMLR and 5-year all-cause mortality of patients with COPD.

Results

The NMLR values of non-surviving patients with COPD were significantly increased compared to the survivors [3.88 (2.53-7.17) vs 2.95 (2.08-4.89), P=0.000]. The area under the NMLR receiver operating characteristic curve for predicting the 5-year all-cause mortality of COPD patients was 0.63. Kaplan-Meier survival curves showed that the 5-year all-cause mortality of COPD patients was significantly increased when the admission peripheral blood NMLR was ≥ 5.90 (27.3% vs 12.4%, P=0.000). The COX regression model showed that NMLR was an independent predictor of 5-year all-cause mortality in COPD patients (hazard ratio=1.84, 95% confidence interval: 1.28-2.64, P=0.001). Moreover, the restricted cubic spline model showed a non-linear relationship between NMLR and COPD death risk (Pnon-linear < 0.05).

Conclusion

The admission peripheral blood NMLR is a significant predictor of 5-year all-cause mortality in patients with COPD, and high NMLR values may indicate a poor clinical prognosis.

Automated CT-based decoupling of the effects of airway narrowing and wall thinning on airway counts in chronic obstructive pulmonary disease

OBJECTIVE

We examine pathways of airway alteration due to wall thinning, narrowing, and obliteration in chronic obstructive pulmonary disease (COPD) using CT-derived airway metrics.

METHODS

Ex-smokers (N = 649; age mean ± std: 69 ± 6 years; 52% male) from the COPDGene Iowa cohort (September 2013-July 2017) were studied. Total airway count (TAC), peripheral TAC beyond 7th generation (TACp), and airway wall thickness (WT) were computed from chest CT scans using previously validated automated methods. Causal relationships among demographic, smoking, spirometry, COPD severity, airway counts, WT, and scanner variables were analysed using causal inference techniques including direct acyclic graphs to assess multi-pathway alterations of airways in COPD.

RESULTS

TAC, TACp, and WT were significantly lower (P < .0001) in mild, moderate, and severe COPD compared to the preserved lung function group. TAC (TACp) losses attributed to narrowing and obliteration of small airways were 4.59%, 13.29%, and 32.58% (4.64%, 17.82%, and 45.51%) in mild, moderate, and severe COPD, while the losses attributed to wall thinning were 8.24%, 17.01%, and 22.95% (12.79%, 25.66%, and 33.95%) in respective groups.

CONCLUSIONS

Different pathways of airway alteration in COPD are observed using CT-derived automated airway metrics. Wall thinning is a dominant contributor to both TAC and TACp loss in mild and moderate COPD while narrowing and obliteration of small airways is dominant in severe COPD.

ADVANCES IN KNOWLEDGE

This automated CT-based study shows that wall thinning dominates airway alteration in mild and moderate COPD while narrowing and obliteration of small airways leads the alteration process in severe COPD.

Exploring the Role of Tertiary Lymphoid Structures Using a Mouse Model of Bacteria-Infected Lungs

Animal models can be helpful tools for deciphering the generation, maintenance, and role of tertiary lymphoid structures (TLS) during infections or tumor development. We describe here the establishment of a persistent lung infection in immune-competent mice by intratracheal instillation of agarose beads containing Pseudomonas aeruginosa or Staphylococcus aureus bacteria. After instillation, animals develop a chronic pulmonary infection, marked by the presence of TLS. This experimental setting allows the study of the function of TLS induced by bacteria encountered in patients with cystic fibrosis (CF) as P. aeruginosa and S. aureus are the two main bacterial strains that infect the bronchi of adult CF patients. Additionally, we describe also how to manipulate the immune response in these infected animals by targeting immune cells involved in TLS function. Overall, this approach makes it possible to explore the role of chronic inflammation in the induction and maintenance of TLS in infected tissues.

Inherent immunity and adaptive immunity: Mechanism and role in AECOPD

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the leading cause of hospitalization and mortality in COPD patients. The occurrence of antibiotic resistance and the progression of non-infectious diseases contribute to poor patient outcomes. Thus, a comprehensive understanding of the mechanisms underlying AECOPD is essential for effective prevention. It is widely acknowledged that the immune system plays a fundamental role in pathogen clearance and the development of inflammation. Immune dysregulation, either due to deficiency or hyperactivity, has been implicated in AECOPD pathogenesis. Therefore, the purpose of this review is to investigate the possible mechanisms underlying dysregulated immune function and disease progression in COPD patients, specifically focusing on the innate and adaptive immune responses. The ultimate aim is to provide new insights for clinical prevention and treatment strategies targeting AECOPD.

Clinical improvements after endoscopic lung volume reduction with valves in patients with advanced emphysema and a 6-min walk test ≤140 m at baseline

Background

Data regarding the effectiveness and safety of endoscopic lung volume reduction with valves (ELVR) in emphysema patients with a very low 6-min walk test (6MWT) are limited. Patients with severe emphysema and very low exercise capacity, as indicated by a 6MWT ≤140 m, are often excluded from clinical studies on ELVR, assuming limited therapeutic benefits and increased complication risk.

Study designs and methods

This study utilised data from the Lungenemphysemregister e.V., a large German national multi-centre prospective open-label clinical trial, and aimed to assess the outcomes of ELVR in patients with a baseline 6MWT ≤140 m and dyspnoea primarily attributed to hyperinflation.

Results

54 patients with a baseline 6MWT ≤140 m and 365 patients with a baseline 6MWT between 140 and 450 m were included in the study. Baseline characteristics were representative for patients with advanced lung emphysema. Patients with a 6MWT ≤140 m at baseline had a lower forced expiratory volume in 1 s and diffusing capacity of the lung for carbon monoxide and higher symptom burden. In the 3-month follow-up, patients of both groups showed statistically significant improvements in lung function parameters, exercise capacity and quality of life parameters compared to baseline. Patients with a 6MWT ≤140 m at baseline showed significantly more 6MWT improvement compared to patients with baseline 6MWT between 140 and 450 m. Moreover, complication rates were similar in both groups.

Interpretation

In summary, the data indicate that ELVR may be an effective and safe treatment for emphysema patients with a very low 6MWT of ≤140 m if very limited exercise capacity is predominately caused by lung emphysema. Therefore future studies should include emphysema patients with a very low 6MWT.

Clinical Characteristics of Chronic Obstructive Pulmonary Disease according to Smoking Status

Chronic obstructive pulmonary disease (COPD) can be caused by various factors, including lung infections, asthma, air pollution, childhood growth disorders, and genetic factors, though smoking is the predominant risk factor. The main pathological mechanisms in COPD involve small airway disease, emphysema, mucus hypersecretion, and vascular disorders. COPD in non-smokers is characterized by a normal 1-second forced expiratory volume decline, equal sex distribution, younger age of onset, fewer comorbidities, milder airflow obstruction, preserved diffusing capacity of the lungs for carbon monoxide, and radiological features such as more air-trapping and less severe emphysema compared to COPD in smokers. Nevertheless, non-smokers with COPD still experience a high prevalence of acute exacerbations, nearly equal to that of smokers with COPD. Moreover, COPD itself is an independent risk factor for developing lung cancer, regardless of smoking status. Given that COPD coexists with numerous comorbidities, effectively managing these comorbidities is crucial, requiring multifaceted efforts for comprehensive treatment.

Lung mucosal immunity to NTHi vaccine antigens: Antibodies in sputum of chronic obstructive pulmonary disease patients

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory illness in older adults. A major cause of COPD-related morbidity and mortality is acute exacerbation of COPD (AECOPD). Bacteria in the lungs play a role in exacerbation development, and the most common pathogen is non-typeable Haemophilus influenzae (NTHi). A vaccine to prevent AECOPD containing NTHi surface antigens was tested in a clinical trial. This study measured IgG and IgA against NTHi vaccine antigens in sputum. Sputum samples from 40 COPD patients vaccinated with the NTHi vaccine were collected at baseline and 30 days after the second dose. IgG and IgA antibodies against the target antigens and albumin were analyzed in the sputum. We compared antibody signals before and after vaccination, analyzed correlation with disease severity and between sputum and serum samples, and assessed transudation. Antigen-specific IgG were absent before vaccination and present with high titers after vaccination. Antigen-specific IgA before and after vaccination were low but significantly different for two antigens. IgG correlated between sputum and serum, and between sputum and disease severity. Sputum albumin was higher in patients with severe COPD than in those with moderate COPD, suggesting changes in transudation played a role. We demonstrated that immunization with the NTHi vaccine induces antigen-specific antibodies in sputum. The correlation between IgG from sputum and serum and the presence of albumin in the sputum of severe COPD patients suggested transudation of antibodies from the serum to the lungs, although local IgG production could not be excluded.Clinical Trial Registration: NCT02075541.

Expression Levels of MUC5AC and MUC5B in Airway Goblet Cells Are Associated with Traits of COPD and Progression of Chronic Airflow Limitation

Mucins 5AC (MUC5AC) and 5B (MUC5B) are the major mucins providing the organizing framework for the airway's mucus gel. We retrieved bronchial mucosal biopsies and bronchial wash (BW) samples through bronchoscopy from patients with chronic obstructive pulmonary disease (n = 38), healthy never-smokers (n = 40), and smokers with normal lung function (n = 40). The expression of MUC5AC and MUC5B was assessed immunohistochemically. The mucin concentrations in BW were determined using the slot-blot technique. The immunohistochemical expression of MUC5AC and MUC5B was localized to goblet cells and submucosal glands. Smokers had higher MUC5AC and lower MUC5B goblet cell expression and higher concentrations of soluble MUC5AC in BW than never-smokers. The MUC5B expression in goblet cells correlated positively with expiratory air flows, diffusing capacity, and the dyspnoea score. Chronic bronchitis, emphysema, and the progression of chronic airflow limitation during a median follow-up time of 8.4 years were associated with higher MUC5AC and lower MUC5B expression in goblet cells. Sustainers, slow progressors, and rapid progressors of airflow obstruction differed in their MUC5B expression at baseline. Emphysema and bronchial wall thickening on CT at a follow-up visit were associated with lower MUC5B expression at baseline. Our findings strengthen the hypothesis that MUC5AC and MUC5B are yet another contributing factor to smoking-associated lung disease progression.

COPD and Immune Checkpoint Inhibitors for Cancer: A Literature Review

Purpose

Immune checkpoint inhibitors are a standard treatment option for many patients with cancer and are most frequently used to treat lung cancer. Chronic obstructive pulmonary disease (COPD) is the most common comorbidity of patients with lung cancer. As the cancer-specific survival of patients with lung cancer continues to increase with modern treatments, it is critical to optimize comorbidities to improve overall survival. This literature review aimed to summarize current research on the impact of COPD upon immunotherapy outcomes.

Methods

A comprehensive search was conducted in the PubMed database using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria focused on peer-reviewed articles published between 2010 and 2024 that addressed COPD, cancer, and immune checkpoint inhibitors. The study team screened the studies for relevance and then synthesized them narratively.

Results

This review identified 37 studies that met the inclusion criteria. Findings suggest that COPD is predictive of improved efficacy but slightly worse toxicity from immune checkpoint inhibitor therapy. The chronic inflammation of COPD leads to immune exhaustion including the overexpression of immune checkpoints on T-cells. Particularly within "hot" tumors that have higher concentrations of tumor-infiltrating lymphocytes, the COPD-related increase in programmed cell death protein 1 (PD-1) signaling likely creates sensitivity to immune checkpoint inhibitors. However, COPD can also lead to respiratory dysfunction, debility, and interstitial lung disease; each of which increases the severity of immune-related adverse events.

Conclusion

COPD is a critical comorbidity that has a significant impact on many patients with cancer who receive treatment with immune checkpoint inhibitors. Future research is needed to design interventions to optimize COPD care in this high-risk patient population.

Lung-resident lymphocytes and their roles in respiratory infections and chronic respiratory diseases

Recent scientific breakthroughs have blurred traditional boundaries between innate and adaptive immunity, revealing a sophisticated network of tissue-resident cells that deliver immediate, localized immune responses. These lymphocytes not only provide rapid frontline defense but also present a paradoxical role in the pathogenesis of respiratory diseases such as asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and the long-term tissue consequences of viral infections including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This review traverses the intricate landscape of lung-resident lymphocytes, delving into their origins, diverse functions, and their dualistic impact on pulmonary health. We dissect their interactions with the microenvironment and the regulatory mechanisms guiding their activity, with an emphasis on their contribution to both immune protection and immunopathology. This review aims to elucidate the complex narrative of these cells, enhancing our understanding of the development of precise therapeutic strategies to combat acute and chronic pulmonary diseases. Through this exploration, the review aspires to shed light on the potential of harnessing lung-resident lymphocytes for the treatment of respiratory conditions.

Causal Role of Immune Cells in Chronic Obstructive Pulmonary Disease: A Two-Sample Mendelian Randomization Study

Accumulating evidence has highlighted the importance of immune cells in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the understanding of the causal association between immunity and COPD remains incomplete due to the existence of confounding variables. In this study, we employed a two-sample Mendelian randomization (MR) analysis, utilizing the genome-wide association study database, to investigate the causal association between 731 immune-cell signatures and the susceptibility to COPD from a host genetics perspective. To validate the consistency of our findings, we utilized MR analysis results of lung function data to assess directional concordance. Furthermore, we employed MR-Egger intercept tests, Cochrane's Q test, MR-PRESSO global test, and "leave-one-out" sensitivity analyses to evaluate the presence of horizontal pleiotropy, heterogeneity, and stability, respectively. Inverse variance weighting results showed that seven immune phenotypes were associated with the risk of COPD. Analyses of heterogeneity and pleiotropy analysis confirmed the reliability of MR results. These results highlight the interactions between the immune system and the lungs. Further investigations into their mechanisms are necessary and will contribute to inform targeted prevention strategies for COPD.

Expression of Semaphorin3E/PlexinD1 in human airway smooth muscle cells of patients with COPD

Semaphorin3E (Sema3E) is a member of axon guidance proteins that have emerged recently as essential regulators of cell migration and proliferation. It binds to PlexinD1 with high affinity and is expressed in different cell types, including immune, cancer, and epithelial cells. Recent work in our lab has revealed a critical immunoregulatory role of Sema3E in experimental allergic asthma; however, its role in chronic obstructive pulmonary disease (COPD) remains unclear. This study aimed to investigate the expression of Sema3E and its receptor, PlexinD1, in the airways of patients with COPD and whether Sema3E regulates airway smooth muscle (ASM) cell proliferation, a key feature of airway remodeling in COPD. We first demonstrate that human ASM cells obtained from COPD express Sema3E and PlexinD1 at both mRNA and protein levels. Also, bronchial sections from patients with COPD displayed immunoreactivity of Sema3E and its receptor PlexinD1, suggestive of functional contribution of Sema3E in airway remodeling. In contrast to ASM cells from healthy donors, Sema3E did not inhibit the platelet-derived growth factor (PDGF) induced cell proliferation in ASM cells of patients with COPD that were consistent with the binding of endogenous Sema3E to its receptors on the cell surface and the expression and release of p61KDa-Sema3E isoform. Our results support the Sema3E-PlexinD1 axis involvement in COPD airway smooth muscle remodeling.NEW & NOTEWORTHY Semaphorin3E (Sema3E), a protein guiding cell movement, is found in various cell types like neural, immune, cancer, and epithelial cells. This study examines Sema3E in chronic obstructive pulmonary disease (COPD) airways. In patients with COPD, airway smooth muscle cells express Sema3E and its receptor PlxD1. Unlike healthy cells, Sema3E does not hinder cell proliferation in COPD, indicating involvement in airway remodeling. These findings highlight the Sema3E-PlxD1 axis in COPD airway changes.

Lung structure and longitudinal change in cardiac structure and function: the MESA COPD Study

BACKGROUND

Lung structure and cardiac structure and function are associated cross-sectionally. The classic literature suggests relationships of airways disease to cor pulmonale and emphysema to reduced cardiac output (CO) but longitudinal data are lacking.

METHODS

The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study was a multicentre longitudinal COPD case-control study of participants 50-79 years with ≥10 pack-years smoking without clinical cardiovascular disease. Segmental airway wall area (WA) and percent emphysema were measured on computed tomography. Right and left ventricle parameters were assessed on cardiac magnetic resonance imaging (cMRI) in exams 6 years apart. Longitudinal and period cross-sectional associations were evaluated with mixed models adjusted for demographics, body size and smoking.

RESULTS

The 187 participants with repeated cMRI were 67±7 years old; 42% had COPD; 22% currently smoked; and the race/ethnicity distribution was 54% White, 30% Black, 14% Hispanic and 3% Asian. Greater WA at enrolment was associated with longitudinal increase in right ventricular (RV) mass (3.5 (95% CI 1.1-5.9) g per 10 mm2 WA). Greater percent emphysema was associated with stably lower left ventricular (LV) end-diastolic volume (-7.8 (95% CI -10.3- -3.0) mL per 5% emphysema) and CO (-0.2 (95% CI -0.4- -0.1) L·min-1 per 5% emphysema).

CONCLUSION

Cardiac associations varied by lung structure over 6 years in this multi-ethnic study. Greater WA at enrolment was associated with longitudinal increases in RV mass, whereas greater percent emphysema was associated with stable decrements in LV filling and CO.

Serum IL-17A and IL-6 in paediatric Mycoplasma pneumoniae pneumonia: implications for different endotypes

Paediatric Mycoplasma pneumoniae pneumonia (MPP) is a heterogeneous disease with a diverse spectrum of clinical phenotypes. No studies have demonstrated the relationship between underlying endotypes and clinical phenotypes as well as prognosis about this disease. Thus, we conducted a multicentre prospective longitudinal study on children hospitalized for MPP between June 2021 and March 2023, with the end of follow-up in August 2023. Blood samples were collected and processed at multiple time points. Multiplex cytokine assay was performed to characterize serum cytokine profiles and their dynamic changes after admission. Cluster analysis based on different clinical phenotypes was conducted. Among the included 196 patients, the levels of serum IL-17A and IL-6 showed remarkable variabilities. Four cytokine clusters based on the two cytokines and four clinical groups were identified. Significant elevation of IL-17A mainly correlated with diffuse bronchiolitis and lobar lesion by airway mucus hypersecretions, while that of IL-6 was largely associated with lobar lesion which later developed into lung necrosis. Besides, glucocorticoid therapy failed to inhibit IL-17A, and markedly elevated IL-17A and IL-6 levels may correlate with lower airway obliterans. Our study provides critical relationship between molecular signatures (endotypes) and clustered clinical phenotypes in paediatric patients with MPP.