Inflammatory endotypes in COPD

Relationship between social participation and depressive symptoms in patients with multimorbidity: the chained mediating role of cognitive function and activities of daily living

OBJECTIVE

The potential mechanisms linking social participation and depressive symptoms in Chinese individuals with multimorbidity are not yet fully understood. This study aims to explore how cognitive function and activities of daily living (ADLs) mediate the relationship between social participation and depressive symptoms in individuals with multimorbidity.

METHODS

We selected 3782 participants with multimorbidity from the 2018 China Health and Retirement Longitudinal Study. Data related to social participation, cognitive function, ADLs, and depressive symptoms were extracted. Regression and Bootstrap analyses were used to explore the sequential mediating effects of social participation, cognitive function, ADLs, and depressive symptoms.

RESULTS

(1) There was a significant correlation between social participation, cognitive function, activities of daily living, and depressive symptoms (p < 0.01). (2) Social participation directly affected depressive symptoms (β = -0.205, p < 0.05). (3) Cognitive function (β = -0.070, p < 0.01) and activities of daily living (β = -0.058, p < 0.01) played separate mediating roles in the effect of social participation on depressive symptoms. (4) Cognitive function and activities of daily living had a chain-mediated role in the relationship between social participation and depressive symptoms in patients with multimorbidity (β = -0.020, p < 0.01).

CONCLUSION

A chained mediating effect was found between cognitive function, ADLs, social participation, and depressive symptoms in patients with multimorbidity. Social participation was found to improve the cognitive function of patients with multimorbidity, which in turn enhanced their daily life activities and ultimately alleviated their depressive symptoms.

Towards precision medicine in COPD: Targeting type 2 cytokines and alarmins

Chronic obstructive pulmonary disease (COPD) is a main global epidemic increasing as population age and affecting approximately 10% of subjects over 45 years. COPD is a heterogeneous inflammatory disease with several endo-phenotypes and clinical presentations. Although neutrophilic inflammation is canonically considered a hallmark of COPD, eosinophilic inflammation can also be present in a subgroup of patients. Several other immune cells and cytokines play a key role in orchestrating and perpetuating the inflammatory pathways in COPD, making them attractive targets for treating this disorder. Recent studies have started to evaluate the possible role of type 2 (T2) inflammation and epithelial-derived alarmins (TSLP and IL-33) in COPD. Two phase III randomized clinical trials (RCTs) showed a modest reduction in exacerbations in COPD patients with eosinophilic phenotype treated with mepolizumab (anti-IL-5) or benralizumab (anti-IL-5Rα). A phase III RCT showed a 30% reduction in exacerbations in COPD patients with ≥ 300 eosinophils/μL treated with dupilumab (anti-IL-4Rα). These results suggest that blocking a single cytokine (e.g., IL-5) or its main target (i.e., IL-5Rα) is less promising than blocking a wider spectrum of cytokines (i.e., IL-4 and IL-13) in COPD. TSLP and IL-33 are upstream regulators of T2-high and T2-low immune responses in airway inflammation. Several ongoing RCTs are evaluating the efficacy and safety of anti-TSLP (tezepelumab), anti-IL-33 (itepekimab, tozorakimab), and anti-ST2 (astegolimab) in patients with COPD, who experience exacerbations. In conclusion, targeting T2 inflammation or epithelial-derived alarmins might represent a step forward in precision medicine for the treatment of a subset of COPD.

DACH1 Attenuates Airway Inflammation in Chronic Obstructive Pulmonary Disease by Activating NRF2 Signaling

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the airways characterized by impaired lung function induced by cigarette smoke (CS). Reduced DACH1 (dachshund homolog 1) expression has a detrimental role in numerous disorders, but its role in COPD remains understudied. This study aimed to elucidate the role and underlying mechanism of DACH1 in airway inflammation in COPD by measuring DACH1 expression in lung tissues of patients with COPD. Airway epithelium-specific DACH1-knockdown mice and adenoassociated virus-transfected DACH1-overexpressing mice were used to investigate the role of DACH1 and the potential for therapeutic targeting in experimental COPD caused by CS. Furthermore, we discovered a potential mechanism of DACH1 in inflammation induced by CS extract stimulation in vitro. Compared with nonsmokers and smokers without COPD, patients with COPD had reduced DACH1 expression, especially in the airway epithelium. Airway epithelium-specific DACH1 knockdown aggravated airway inflammation and lung function decline caused by CS in mice, whereas DACH1 overexpression protected mice from airway inflammation and lung function decline. DACH1 knockdown and overexpression promoted and inhibited IL-6 and IL-8 secretion, respectively, in 16HBE human bronchial epidermal cells after CS extract stimulation. NRF2 (nuclear factor erythroid 2-related factor 2) was discovered to be a novel downstream target of DACH1, which binds directly to its promoter. By activating NRF2 signaling, DACH1 induction reduced inflammation. DACH1 levels are lower in smokers and nonsmoking patients with COPD than in nonsmokers. DACH1 has protective effects against inflammation induced by CS by activating the NRF2 signaling pathway. Targeting DACH1 is a potentially viable therapeutic approach for COPD treatment.

Pseudomonas aeruginosa in chronic lung disease: untangling the dysregulated host immune response

Pseudomonas aeruginosa is a highly adaptable opportunistic pathogen capable of exploiting barriers and immune defects to cause chronic lung infections in conditions such as cystic fibrosis. In these contexts, host immune responses are ineffective at clearing persistent bacterial infection, instead driving a cycle of inflammatory lung damage. This review outlines key components of the host immune response to chronic P. aeruginosa infection within the lung, beginning with initial pathogen recognition, followed by a robust yet maladaptive innate immune response, and an ineffective adaptive immune response that propagates lung damage while permitting bacterial persistence. Untangling the interplay between host immunity and chronic P. aeruginosa infection will allow for the development and refinement of strategies to modulate immune-associated lung damage and potentiate the immune system to combat chronic infection more effectively.

Activated eosinophils in early life impair lung development and promote long-term lung damage

Exaggeration of type 2 immune responses promotes lung inflammation and altered lung development; however, eosinophils, despite expansion in the postnatal lung, have not been specifically assessed in the context of neonatal lung disease. Furthermore, early life factors including prematurity and respiratory infection predispose infants to chronic obstructive pulmonary disease later in life. To assess eosinophils in the developing lung and how they may contribute to chronic lung disease, we generated mice harboring eosinophil-specific deletion of the negative regulatory enzyme SH2 domain-containing inositol 5' phosphatase-1. This increased the activity and number of pulmonary eosinophils in the developing lung, which was associated with impaired lung development, expansion of activated alveolar macrophages (AMφ), multinucleated giant cell formation, enlargement of airspaces, and fibrosis. Despite regression of eosinophils following completion of lung development, AMφ-dominated inflammation persisted, alongside lung damage. Bone marrow chimera studies showed that SH2 domain-containing inositol 5' phosphatase-1-deficient eosinophils were not sufficient to drive inflammatory lung disease in adult steady-state mice but once inflammation and damage were present, it could not be resolved. Depletion of eosinophils during alveolarization alleviated pulmonary inflammation and lung pathology, demonstrating an eosinophil-intrinsic effect. These results show that the presence of activated eosinophils during alveolarization aggravates AMφs and promotes sustained inflammation and long-lasting lung pathology.

Rheumatoid arthritis and changes on spirometry by smoking status in two prospective longitudinal cohorts

OBJECTIVE

To compare longitudinal changes in spirometric measures between patients with rheumatoid arthritis (RA) and non-RA comparators.

METHODS

We analysed longitudinal data from two prospective cohorts: the UK Biobank and COPDGene. Spirometry was conducted at baseline and a second visit after 5-7 years. RA was identified based on self-report and disease-modifying antirheumatic drug use; non-RA comparators reported neither. The primary outcomes were annual changes in the per cent-predicted forced expiratory volume in 1 s (FEV1%) and per cent predicted forced vital capacity (FVC%). Statistical comparisons were performed using multivariable linear regression. The analysis was stratified based on baseline smoking status and the presence of obstructive pattern (FEV1/FVC <0.7).

RESULTS

Among participants who underwent baseline and follow-up spirometry, we identified 233 patients with RA and 37 735 non-RA comparators. Among never-smoking participants without an obstructive pattern, RA was significantly associated with more FEV1% decline (β=-0.49, p=0.04). However, in ever smokers with ≥10 pack-years, those with RA exhibited significantly less FEV1% decline than non-RA comparators (β=0.50, p=0.02). This difference was more pronounced among those with an obstructive pattern at baseline (β=1.12, p=0.01). Results were similar for FEV1/FVC decline. No difference was observed in the annual FVC% change in RA versus non-RA.

CONCLUSIONS

Smokers with RA, especially those with baseline obstructive spirometric patterns, experienced lower FEV1% and FEV1/FVC decline than non-RA comparators. Conversely, never smokers with RA had more FEV1% decline than non-RA comparators. Future studies should investigate potential treatments and the pathogenesis of obstructive lung diseases in smokers with RA.

Association between systemic inflammatory markers and chronic obstructive pulmonary disease: A population-based study

Objective

To investigate whether inflammatory indices, including the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), product of platelet and neutrophil count (PPN), and lymphocyte-to-monocyte ratio (LMR), correlate with chronic obstructive pulmonary disease (COPD).

Methods

This was a cross-sectional study from the National Health and Nutrition Examination Survey (NHANES) database 2007-2018. The SII, NLR, PLR, PPN and LMR were calculated based on blood cell counts and were log2-transformed. COPD was diagnosed via a questionnaire or spirometry examination. Multivariate logistic regression, sensitivity analysis, subgroup analyses, and interaction tests were performed to evaluate the relationships.

Results

23,875 participants, including 1000 COPD patients (453 diagnosed via spirometry examination, 547 diagnosed via a questionnaire), were enrolled in this study. Positive associations were observed between SII (OR 1.231, 95 % CI 1.081,1.401), NLR (OR 1.223, 95 % CI 1.064,1.405), PLR (OR 1.325, 95 % CI 1.086,1.617), PPN (OR 1.157, 95 % CI 1.031,1.298) and COPD, while a negative association was obtained between LMR and COPD (OR 0.794, 95 % CI 0.666,0.948) after covariate adjustments. When divided COPD patients into spirometry-based and questionnaire-based, only SII (OR 1.310, 95%CI 1.122,1.529), PLR (OR 1.669, 95%CI 1.272,2.191) and PPN (OR 1.218, 95%CI 1.050,1.412) significantly correlated with spirometry-based COPD, while only NLR (OR 1.303, 95%CI 1.055,1.609) and LMR (OR 0.524, 95%CI 0.406,0.677) significantly correlated with questionnaire-based COPD after covariate adjustments.

Conclusion

Significant associations are observed between different inflammation indices and COPD. Heterogeneity exists between spirometry-based and questionnaire-based COPD patients. Future studies are needed to verify the results.

Association of dietary inflammatory indices with sarcopenia and all-cause mortality in COPD patients

Background

Sarcopenia frequently occurs as a comorbidity in individuals with COPD. However, research on the impact of Appendicular Skeletal Muscle Mass (ASM) on survival in COPD patients is scarce. Moreover, there is a lack of research on the association between dietary pro-inflammatory capacity and sarcopenia in COPD.

Methods

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) covering the years 1999 to 2006 and 2011 to 2018. We aimed to investigate the relationship between the Dietary Inflammatory Index (DII) and sarcopenia prevalence among adults diagnosed with COPD in the United States. Furthermore, we sought to explore the relationship between sarcopenia, ASMI, and all-cause mortality. The study included a total of 1,429 eligible adult participants, divided into four groups based on quartiles of DII, with adjustments for sample weights. Methodologically, we used multivariable logistic regression analyses and to examine the association between DII and sarcopenia. Additionally, we used restricted cubic spline (RCS) tests to evaluate potential non-linear relationships. To assess the effect of sarcopenia on overall all-cause mortality, we used Kaplan-Meier models and Cox proportional hazards models. Moreover, we used RCS analyses to investigate potential non-linear relationships between ASMI and all-cause mortality. Subgroup analyses were conducted to confirm the reliability of our study findings.

Results

In our COPD participant cohort, individuals with higher DII scores were more likely to be female, unmarried, have lower educational attainment, and show lower ASMI. Using multivariable logistic regression models, we found a positive association between the highest quartile of DII levels and sarcopenia incidence [Odds Ratio (OR) 2.37; 95% Confidence Interval (CI) 1.26-4.48; p = 0.01]. However, analysis of RCS curves did not show a non-linear relationship between DII and sarcopenia. Throughout the entire follow-up period, a total of 367 deaths occurred among all COPD patients. Kaplan-Meier survival curves showed a significantly higher all-cause mortality rate among individuals with concurrent sarcopenia (p < 0.0001). Cox proportional hazards model analysis showed a 44% higher risk of all-cause mortality among COPD patients with sarcopenia compared to those without sarcopenia [Hazard Ratio (HR): 1.44; 95% CI 1.05-1.99; p < 0.05]. Additionally, our final RCS analyses revealed a significant non-linear association between ASMI levels and all-cause mortality among COPD patients, with a turning point identified at 8.32 kg/m2. Participants with ASMI levels above this inflection point had a 42% lower risk of all-cause mortality compared to those with ASMI levels below it (HR 0.58; 95% CI 0.48-0.7).

Conclusion

We observed a significant association between concurrent sarcopenia and an increased risk of all-cause mortality in COPD patients within the United States. Moreover, ASMI demonstrated a non-linear association with all-cause mortality, with a critical threshold identified at 8.32 kg/m2. Our findings also revealed an association between DII and the presence of sarcopenia. Consequently, further investigations are warranted to explore the feasibility of dietary DII adjustments as a means to mitigate muscle wasting and enhance the prognosis of COPD.

Airway inflammation in a novel mouse model of asthma-COPD overlap induced by co-exposure to papain and tobacco smoke

Asthma and chronic obstructive pulmonary disease (COPD) are respiratory diseases associated with airway inflammation, which is the main pathogenesis. Although their causes and characteristics differ, in some cases, asthma and COPD may coexist in the same patient in a condition called asthma-COPD overlap (ACO). The prognosis of ACO is more unfavourable than those of asthma or COPD alone, without any treatment strategies demonstrating efficacy. Owing to its intricate spectrum of features, the detailed pathogenesis of how ACO exacerbates respiratory features remains unclear. In this study, we exposed papain-induced asthma model mice to tobacco smoke to establish an ACO mouse model, in which features of airway inflammation observed in both asthma and COPD were incorporated. This model exhibited distinctive mixed and corticosteroid-resistant airway inflammation and emphysematous changes that are characteristic of ACO. The novel mouse model established here is expected to significantly contribute to elucidating the mechanisms of the broad pathologies of ACO and identifying potential therapeutic targets.

Aerobic exercise training engages the canonical wnt pathway to improve pulmonary function and inflammation in COPD

BACKGROUND

We studied whether the exercise improves cigarette smoke (CS) induced chronic obstructive pulmonary disease (COPD) in mice through inhibition of inflammation mediated by Wnt/β-catenin-peroxisome proliferator-activated receptor (PPAR) γ signaling.

METHODS

Firstly, we observed the effect of exercise on pulmonary inflammation, lung function, and Wnt/β-catenin-PPARγ. A total of 30 male C57BL/6J mice were divided into the control group (CG), smoke group (SG), low-intensity exercise group (LEG), moderate-intensity exercise group (MEG), and high-intensity exercise group (HEG). All the groups, except for CG, underwent whole-body progressive exposure to CS for 25 weeks. Then, we assessed the maximal exercise capacity of mice from the LEG, MEG, and HEG, and performed an 8-week treadmill exercise intervention. Then, we used LiCl (Wnt/β-catenin agonist) and XAV939 (Wnt/β-catenin antagonist) to investigate whether Wnt/β-catenin-PPARγ pathway played a role in the improvement of COPD via exercise. Male C57BL/6J mice were randomly divided into six groups (n = 6 per group): CG, SG, LiCl group, LiCl and exercise group, XAV939 group, and XAV939 and exercise group. Mice except those in the CG were exposed to CS, and those in the exercise groups were subjected to moderate-intensity exercise training. All the mice were subjected to lung function test, lung histological assessment, and analysis of inflammatory markers in the bronchoalveolar lavage fluid, as well as detection of Wnt1, β-catenin and PPARγ proteins in the lung tissue.

RESULTS

Exercise of various intensities alleviated lung structural changes, pulmonary function and inflammation in COPD, with moderate-intensity exercise exhibiting significant and comprehensive effects on the alleviation of pulmonary inflammation and improvement of lung function. Low-, moderate-, and high-intensity exercise decreased β-catenin levels and increased those of PPARγ significantly, and only moderate-intensity exercise reduced the level of Wnt1 protein. Moderate-intensity exercise relieved the inflammation aggravated by Wnt agonist. Wnt antagonist combined with moderate-intensity exercise increased the levels of PPARγ, which may explain the highest improvement of pulmonary function observed in this group.

CONCLUSIONS

Exercise effectively decreases COPD pulmonary inflammation and improves pulmonary function. The beneficial role of exercise may be exerted through Wnt/β-catenin-PPARγ pathway.

Identification and experimental validation of PYCARD as a crucial PANoptosis-related gene for immune response and inflammation in COPD

Chronic inflammatory and immune responses play key roles in the development and progression of chronic obstructive pulmonary disease (COPD). PANoptosis, as a unique inflammatory cell death modality, is involved in the pathogenesis of many inflammatory diseases. We aim to identify critical PANoptosis-related biomarkers and explore their potential effects on respiratory tract diseases and immune infiltration landscapes in COPD. Total microarray data consisting of peripheral blood and lung tissue datasets associated with COPD were obtained from the GEO database. PANoptosis-associated genes in COPD were identified by intersecting differentially expressed genes (DEGs) with genes involved in pyroptosis, apoptosis, and necroptosis after normalizing and removing the batch effect. Furthermore, GO, KEGG, PPI network, WGCNA, LASSO-COX, and ROC curves analysis were conducted to screen and verify hub genes, and the correlation between PYCARD and infiltrated immune cells was analyzed. The effect of PYCARD on respiratory tract diseases and the potential small-molecule agents for the treatment of COPD were identified. PYCARD expression was verified in the lung tissue of CS/LPS-induced COPD mice. PYCARD was a critical PANoptosis-related gene in all COPD patients. PYCARD was positively related to NOD-like receptor signaling pathway and promoted immune cell infiltration. Moreover, PYCARD was significantly activated in COPD mice mainly by targeting PANoptosis. PANoptosis-related gene PYCARD is a potential biomarker for COPD diagnosis and treatment.

Inflammation mediates the association between furan exposure and the prevalence and mortality of chronic obstructive pulmonary disease: National Health and Nutrition Examination Survey 2013-2018

BACKGROUND

Although extensive research has established associations between chronic obstructive pulmonary disease (COPD) and environmental pollutants, the connection between furan and COPD remains unclear. This study aimed to explore the association between furan and COPD while investigating potential mechanisms.

METHODS

The study involved 7,482 adults from the National Health and Nutrition Examination Survey 2013-2018. Exposure to furan was assessed using blood furan levels. Participants were categorized into five groups based on quartiles of log10-transformed blood furan levels. Logistic regression and restricted cubic spline regression models were used to assess the association between furan exposure and COPD risk. Mediating analysis was performed to assess the contribution of inflammation to the effects of furan exposure on COPD prevalence. Cox regression was used to assess the association between furan exposure and the prognosis of COPD.

RESULTS

Participants with COPD exhibited higher blood furan levels compared to those without COPD (P < 0.001). Log10-transformed blood furan levels were independently associated with an increased COPD risk after adjusting for all covariates (Q5 vs. Q1: OR = 4.47, 95% CI = 1.58-12.66, P = 0.006, P for trend = 0.001). Inflammatory cells such as monocytes, neutrophils, and basophils were identified as mediators in the relationship between furan exposure and COPD prevalence, with mediated proportions of 8.73%, 20.90%, and 10.94%, respectively (all P < 0.05). Moreover, multivariate Cox regression analysis revealed a positive correlation between log10-transformed blood furan levels and respiratory mortality in COPD patients (HR = 41.00, 95% CI = 3.70-460.00, P = 0.003).

CONCLUSIONS

Exposure to furan demonstrates a positive correlation with both the prevalence and respiratory mortality of COPD, with inflammation identified as a crucial mediator in this relationship.

Chronic obstructive pulmonary disease and the airway microbiome: A review for clinicians

Chronic obstructive pulmonary disease (COPD) is a complex heterogeneous disease characterized by progressive airflow limitation and chronic inflammation. The progressive development and long-term repeated acute exacerbation of COPD make many patients still unable to control the deterioration of the disease after active treatment, and even eventually lead to death. An increasing number of studies have shown that the occurrence and development of COPD are closely related to the composition and changes of airway microbiome. This article reviews the interaction between COPD and airway microbiome, the potential mechanisms of interaction, and the treatment methods related to microbiome. We elaborated the internal correlation between airway microbiome and different stages of COPD, inflammatory endotypes, glucocorticoid and antibiotic treatment, analyze the pathophysiological mechanisms such as the "vicious cycle" hypothesis, abnormal inflammation-immune response of the host and the "natural selection" of COPD to airway microbiome, introduce the treatment of COPD related to microbiome and emphasize the predictive value of airway microbiome for the progression, exacerbation and prognosis of COPD, as well as the guiding role for clinical management of patients, in order to provide a new perspective for exploring the pathogenesis of COPD, and also provide clues and guidance for finding new treatment targets.

Molecular mechanism of Jianpiyifei II granules in the treatment of chronic obstructive pulmonary disease: Network pharmacology analysis, molecular docking, and experimental assessment

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is defined by persistent airway and lung inflammation, excessive mucus production, remodeling of the airways, and damage to the alveolar tissue. Based on clinical experience, it has been observed that Jianpiyifei II (JPYF II) granules exhibit a significant therapeutic impact on individuals suffering from stable COPD. Nevertheless, the complete understanding of JPYF II's potential mode of action against COPD remains to be further clarified.

PURPOSE

To further investigate the underlying mechanism of JPYF II for treating COPD and clarify the role of the IL-17 pathway in the treatment.

METHODS

A variety of databases were utilized to acquire JPYF II's bioactive components, as well as related targets of JPYF II and COPD. Cytoscape was utilized to establish multiple interaction networks for the purpose of topological analyses and core-target screening. The Metascape was utilized to identify the function of target genes and crucial signaling pathways. To evaluate the interactions between bioactive ingredients and central target proteins, molecular docking simulations were conducted. Following that, a sequence of experiments was conducted both in the laboratory and in living organisms, which included analyzing the cell counts in bronchoalveolar lavage fluid (BALF), examining lung tissue for histopathological changes, conducting immunohistochemistry, RT‒qPCR, ELISA, and Western blotting.

RESULTS

In JPYF II, 88 bioactive ingredients were predicted to have a total of 342 targets. After conducting Venn analysis, it was discovered that 284 potential targets of JPYF II were linked to the provision of defensive benefits against COPD. The PPI network yielded a total of twenty-four core targets. The findings from the analysis of enrichment and gene‒pathway network suggested that JPYF II targeted Hsp90, MAPKs, ERK, AP-1, TNF-α, IL-6, COX-2, CXCL8, and MMP-9 as crucial elements for COPD treatment through the IL-17 pathway. Additionally, JPYF II might modulate MAPK signaling pathways and the downstream transcription factor AP-1 via IL-17 regulation. According to the findings from molecular docking, it was observed that the 24 core target proteins exhibited robust binding affinities towards the top 10 bioactive compounds. Furthermore, the treatment of COPD through the regulation of MAPKs in the IL-17 pathway was significantly influenced by flavonoids and sterols found in JPYF II. In vitro, these observations were further confirmed. In vivo results demonstrated that JPYF II reduced inflammatory cell infiltration in pulmonary tissues and the quantity of inflammatory cells in BALF obtained from LPS- and CS-stimulated mice. Moreover, the administration of JPYF II resulted in the inhibition of IL-17 mRNA and protein levels, phosphorylation levels of MAPK proteins, and expression of phosphorylated AP-1 proteins. It also suppressed the expression of downstream effector genes and proteins associated with the IL-17/MAPK/AP-1 signaling axis in lung tissues and BALF.

CONCLUSION

This research reveals that JPYF II improves COPD by controlling the IL-17/MAPK/AP-1 signaling axis within the IL-17 pathway for the first time. These findings offer potential approaches for the creation of novel medications that specifically target IL-17 and proteins involved in the IL-17 pathway to address COPD.

A novel quinoline with airway relaxant effects and anti-inflammatory properties

BACKGROUND

In chronic pulmonary diseases characterized by inflammation and airway obstruction, such as asthma and COPD, there are unmet needs for improved treatment. Quinolines is a group of small heterocyclic compounds that have a broad range of pharmacological properties. Here, we investigated the airway relaxant and anti-inflammatory properties of a novel quinoline (RCD405).

METHODS

The airway relaxant effect of RCD405 was examined in isolated airways from humans, dogs, rats and mice. Murine models of ovalbumin (OVA)-induced allergic asthma and LPS-induced airway inflammation were used to study the effects in vivo. RCD405 (10 mg/kg) or, for comparisons in selected studies, budesonide (3 mg/kg), were administered intratracheally 1 h prior to each challenge. Airway responsiveness was determined using methacholine provocation. Immune cell recruitment to bronchi was measured using flow cytometry and histological analyses were applied to investigate cell influx and goblet cell hyperplasia of the airways. Furthermore, production of cytokines and chemokines was measured using a multiplex immunoassay. The expression levels of asthma-related genes in murine lung tissue were determined by PCR. The involvement of NF-κB and metabolic activity was measured in the human monocytic cell line THP-1.

RESULTS

RCD405 demonstrated a relaxant effect on carbachol precontracted airways in all four species investigated (potency ranking: human = rat > dog = mouse). The OVA-specific IgE and airway hyperresponsiveness (AHR) were significantly reduced by intratracheal treatment with RCD405, while no significant changes were observed for budesonide. In addition, administration of RCD405 to mice significantly decreased the expression of proinflammatory cytokines and chemokines as well as recruitment of immune cells to the lungs in both OVA- and LPS-induced airway inflammation, with a similar effect as for budesonide (in the OVA-model). However, the effect on gene expression of Il-4, IL-5 and Il-13 was more pronounced for RCD405 as compared to budesonide. Finally, in vitro, RCD405 reduced the LPS-induced NF-κB activation and by itself reduced cellular metabolism.

CONCLUSIONS

RCD405 has airway relaxant effects, and it reduces AHR as well as airway inflammation in the models used, suggesting that it could be a clinically relevant compound to treat inflammatory airway diseases. Possible targets of this compound are complexes of mitochondrial oxidative phosphorylation, resulting in decreased metabolic activity of targeted cells as well as through pathways associated to NF-κB. However, further studies are needed to elucidate the mode of action.

Putative Molecular Mechanisms Underpinning the Inverse Roles of Mitochondrial Respiration and Heme Function in Lung Cancer and Alzheimer's Disease

Mitochondria are the powerhouse of the cell. Mitochondria serve as the major source of oxidative stress. Impaired mitochondria produce less adenosine triphosphate (ATP) but generate more reactive oxygen species (ROS), which could be a major factor in the oxidative imbalance observed in Alzheimer's disease (AD). Well-balanced mitochondrial respiration is important for the proper functioning of cells and human health. Indeed, recent research has shown that elevated mitochondrial respiration underlies the development and therapy resistance of many types of cancer, whereas diminished mitochondrial respiration is linked to the pathogenesis of AD. Mitochondria govern several activities that are known to be changed in lung cancer, the largest cause of cancer-related mortality worldwide. Because of the significant dependence of lung cancer cells on mitochondrial respiration, numerous studies demonstrated that blocking mitochondrial activity is a potent strategy to treat lung cancer. Heme is a central factor in mitochondrial respiration/oxidative phosphorylation (OXPHOS), and its association with cancer is the subject of increased research in recent years. In neural cells, heme is a key component in mitochondrial respiration and the production of ATP. Here, we review the role of impaired heme metabolism in the etiology of AD. We discuss the numerous mitochondrial effects that may contribute to AD and cancer. In addition to emphasizing the significance of heme in the development of both AD and cancer, this review also identifies some possible biological connections between the development of the two diseases. This review explores shared biological mechanisms (Pin1, Wnt, and p53 signaling) in cancer and AD. In cancer, these mechanisms drive cell proliferation and tumorigenic functions, while in AD, they lead to cell death. Understanding these mechanisms may help advance treatments for both conditions. This review discusses precise information regarding common risk factors, such as aging, obesity, diabetes, and tobacco usage.

Downregulated BMP-Smad1/5/8 signaling causes emphysema via dysfunction of alveolar type II epithelial cells

Bone morphogenetic protein (BMP)-Smad1/5/8 signaling plays a crucial regulatory role in lung development and adult lung homeostasis. However, it remains elusive whether BMP-Smad1/5/8 signaling is involved in the pathogenesis of emphysema. In this study, we downregulated BMP-Smad1/5/8 signaling by overexpressing its antagonist Noggin in adult mouse alveolar type II epithelial cells (AT2s), resulting in an emphysematous phenotype mimicking the typical pathological features of human emphysema, including distal airspace enlargement, pulmonary inflammation, extracellular matrix remodeling, and impaired lung function. Dysregulation of BMP-Smad1/5/8 signaling in AT2s leads to inflammatory destruction dominated by macrophage infiltration, associated with reduced secretion of surfactant proteins and inhibition of AT2 proliferation and differentiation. Reactivation of BMP-Smad1/5/8 signaling by genetics or chemotherapy significantly attenuated the morphology and pathophysiology of emphysema and improved the lung function in Noggin-overexpressing lungs. We also found that BMP-Smad1/5/8 signaling was downregulated in cigarette smoke-induced emphysema, and that enhancing its activity in AT2s prevented or even reversed emphysema in the mouse model. Our data suggest that BMP-Smad1/5/8 signaling, located at the top of the signaling cascade that regulates lung homeostasis, represents a key molecular regulator of alveolar stem cell secretory and regenerative function, and could serve as a potential target for future prevention and treatment of pulmonary emphysema. © 2023 The Pathological Society of Great Britain and Ireland.

Enhanced prothrombotic and proinflammatory activity of circulating extracellular vesicles in acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) are associated with a high rate of cardiovascular events. Thromboinflammation (the interplay between coagulation and inflammation) is probably involved in these events. Extracellular vesicles (EV) increase during AE-COPD, but their role in thromboinflammation in COPD is still unknown. We investigated EV-associated prothrombotic and proinflammatory activity in COPD.

METHODS

Patients with AE-COPD, stable COPD (sCOPD) and age- and sex-matched subjects (controls) were enrolled. AE-COPD patients were evaluated at hospital admission and 8 weeks after discharge (recovery; longitudinal arm). In a cross-sectional arm, AE-COPD were compared with sCOPD and controls. EV-mediated prothrombotic activity was tested by measuring the concentration of EV-associated phosphatidylserine, as assessed by a prothrombinase assay, and tissue factor, as assessed by a modified one-stage clotting assay (EV-PS and EV-TF, respectively). Synthesis of interleukin-8 (IL-8) and C-C motif chemokine ligand-2 (CCL-2) by cells of the human bronchial epithelial cell line 16HBE incubated with patients' EV was used to measure EV-mediated proinflammatory activity.

RESULTS

Twenty-five AE-COPD (median age [interquartile range] 74.0 [14.0] years), 31 sCOPD (75.0 [9.5] years) and 12 control (67.0 [3.5] years) subjects were enrolled. In the longitudinal arm, EV-PS, EV-TF, IL-8 and CCL-2 levels were all significantly higher at hospital admission than at recovery. Similarly, in the cross-sectional arm, EV-PS, EV-TF and cytokines synthesis were significantly higher in AE-COPD than in sCOPD and controls.

CONCLUSIONS

EV exert prothrombotic and proinflammatory activities during AE-COPD and may therefore be effectors of thromboinflammation, thus contributing to the higher cardiovascular risk in AE-COPD.

Exploring the importance of m5c in the diagnosis and subtype classification of COPD using the GEO database

BACKGROUND

5-Methylcytosine (m5C) is an mRNA modifier that is associated with the occurrence and development of viral infection, pulmonary fibrosis, lung cancer, and other diseases. However, the role of m5C regulators in chronic obstructive pulmonary disease (COPD) remains unknown.

METHODS

In this study, by analysing the GSE42057 dataset, the differential expression of m5c regulators in the COPD group and control group was obtained, and a correlation analysis was conducted. The random forest model and support vector machine model were used to predict the occurrence of COPD. A nomogram model was also constructed to predict the prevalence of COPD. The COPD patients were divided into subtypes by consistent cluster analysis based on m5c methylation regulators. Immune cell infiltration was performed on the m5c methylation subtypes. Differentially expressed genes (DEGs) between m5c methylation subtypes were screened, and the DEGs were analysed by Gene Ontology (GO) Kyoto Encyclopedia of Genes and Genomes (KEGG). Finally, we verified the expression of several m5C regulators and related pathways using a COPD cell model.

RESULTS

Seven m5c methylation regulators were differentially expressed. The random forest model based on the above genes was the most accurate for predicting the occurrence of COPD. A nomogram model based on the above genes could also accurately predict the prevalence of COPD, and the implementation of these models could benefit COPD patients. The consistent cluster analysis divided the COPD patients into two subtypes (Cluster A and Cluster B). The main component analysis algorithm determined the m5c methylation subtypes and found that patients in Cluster A had a higher m5c score than those in Cluster B. GO analysis of the DEGs between the m5c methylation COPD patient subtypes revealed that DEGS were mainly enriched in leukocyte-mediated immunity and regulation of T-cell activation. KEGG analysis revealed that DEGS were mainly enriched in Th1 and Th2 cell differentiation, neutrophil extracellular trap formation, and the NF-κB signalling pathway. Immunocyte correlation analysis revealed that Cluster B was associated with neutrophil- and macrophage-mediated immunity, while Cluster A was associated with CD4 + T-cell- and CD8 + T-cell-mediated immunity. Cell experiments have also verified some of the above research results.

CONCLUSION

The diagnosis and subtype classification of COPD patients based on m5c regulators may provide a new strategy for the diagnosis and treatment of COPD.

The association between blood eosinophils and clinical outcome of acute exacerbations of chronic obstructive pulmonary disease: A systematic review and meta-analysis

OBJECTIVES

Studies have shown an association between eosinophilia and clinical outcomes in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, contradictory findings exist. Our study aims to systematically evaluate the association between elevated peripheral blood eosinophils and clinical outcome of patients with AECOPD.

METHODS

An electronic search was conducted for relevant studies published from database inception to February 28, 2023, on PubMed, EMBASE, Cochrane Library, and Web of Science. The analysis covered studies on the correlation between EOS AECOPD and mortality, hospital stay duration, readmission and hospitalization rates, and invasive mechanical ventilation. Where applicable, relative risk (RR) and weighted mean difference (WMD) were extracted, pooled, and assessed using meta-analysis. Sensitivity analysis was performed to explore the source of heterogeneity.

RESULTS

Fifteen high-quality studies including 14 cohort studies and one case-control study were included in the meta-analysis. Compared with non-eosinophilic AECOPD patients, those with eosinophilic AECOPD had a lower risk of mortality (RR = 0.65, 95 % confidence interval [CI] 0.54, 0.77, P < 0.001), shorter length of hospital stay (WMD = -1.56, 95%CI -2.16, -0.96, P < 0.001), and higher readmission rate (RR = 1.07, 95%CI 1.01,1.13, P = 0.029). No difference was found concerning the rate of hospitalization and invasive mechanical ventilation between the two groups.

CONCLUSION

Individuals diagnosed with eosinophilic AECOPD had a reduced mortality rate, a truncated period of hospitalization, and an insubstantial increase in the probability of readmission relative to their non-eosinophilic AECOPD counterparts. The level of eosinophils in blood has been shown to serve as a potential predictive biomarker for AECOPD patients.

Biomass-related PM2.5 induced inflammatory microenvironment via IL-17F/IL-17RC axis

Biomass exposure is a significant environmental risk factor for COPD, but the underlying mechanisms have not yet been fully elucidated. Inflammatory microenvironment has been shown to drive the development of many chronic diseases. Pollution exposure can cause increased levels of inflammatory factors in the lungs, leading to an inflammatory microenvironment which is prevalent in COPD. Our findings revealed that IL-17F was elevated in COPD, while exposure to biomass led to increased expression of IL-17F in both alveolar epithelial and macrophage cells in mice. Blocking IL-17F could alleviate the lung inflammation induced by seven days of biomass exposure in mice. We employed a transwell co-culture system to simulate the microenvironment and investigate the interactions between MLE-12 and MH-S cells. We demonstrated that anti-IL-17F antibody attenuated the inflammatory responses induced by BRPM2.5 in MLE-12 and MH-S co-cultured with BRPM2.5-MLE-12, which reduced inflammatory changes in microenvironment. We found that IL-17RC, an important receptor for IL-17F, played a key role in the interactions. Knockout of IL-17RC in MH-S resulted in inhibited IL-17F signaling and attenuated inflammatory response after MH-S co-culture with BRPM2.5-MLE-12. Our investigation suggests that BRPM2.5 induces lung epithelial-macrophage interactions via IL-17F/IL-17RC axis regulating the inflammatory response. These results may provide a novel strategy for effective prevention and treatment of biomass-related COPD.

Neutrophil extracellular traps and their implications in airway inflammatory diseases

Neutrophil extracellular traps (NETs) are essential for immune defense and have been increasingly recognized for their role in infection and inflammation. In the context of airway inflammatory diseases, there is growing evidence suggesting the involvement and significance of NETs. This review aims to provide an overview of the formation mechanisms and components of NETs and their impact on various airway inflammatory diseases, including acute lung injury/ARDS, asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. By understanding the role of NETs in airway inflammation, we can gain valuable insights into the underlying pathogenesis of these diseases and identify potential targets for future therapeutic strategies that either target NETs formation or modulate their harmful effects. Further research is warranted to elucidate the complex interactions between NETs and airway inflammation and to develop targeted therapies that can effectively mitigate their detrimental effects while preserving their beneficial functions in host defense.

Nicotinic acetylcholine receptor signaling maintains epithelial barrier integrity

Disruption of epithelial barriers is a common disease manifestation in chronic degenerative diseases of the airways, lung, and intestine. Extensive human genetic studies have identified risk loci in such diseases, including in chronic obstructive pulmonary disease (COPD) and inflammatory bowel diseases. The genes associated with these loci have not fully been determined, and functional characterization of such genes requires extensive studies in model organisms. Here, we report the results of a screen in Drosophila melanogaster that allowed for rapid identification, validation, and prioritization of COPD risk genes that were selected based on risk loci identified in human genome-wide association studies (GWAS). Using intestinal barrier dysfunction in flies as a readout, our results validate the impact of candidate gene perturbations on epithelial barrier function in 56% of the cases, resulting in a prioritized target gene list. We further report the functional characterization in flies of one family of these genes, encoding for nicotinic acetylcholine receptor (nAchR) subunits. We find that nAchR signaling in enterocytes of the fly gut promotes epithelial barrier function and epithelial homeostasis by regulating the production of the peritrophic matrix. Our findings identify COPD-associated genes critical for epithelial barrier maintenance, and provide insight into the role of epithelial nAchR signaling for homeostasis.

RNA-Binding Proteins as a Molecular Link between COPD and Lung Cancer

Chronic obstructive pulmonary disease (COPD) represents an independent risk factor for lung cancer development. Accelerated cell senescence, induced by oxidative stress and inflammation, is a common pathogenic determinant of both COPD and lung cancer. The post transcriptional regulation of genes involved in these processes is finely regulated by RNA-binding proteins (RBPs), which regulate mRNA turnover, subcellular localization, splicing and translation. Multiple pro-inflammatory mediators (including cytokines, chemokines, proteins, growth factors and others), responsible of lung microenvironment alteration, are regulated by RBPs. Several mouse models have shown the implication of RBPs in multiple mechanisms that sustain chronic inflammation and neoplastic transformation. However, further studies are required to clarify the role of RBPs in the pathogenic mechanisms shared by lung cancer and COPD, in order to identify novel biomarkers and therapeutic targets. This review will therefore focus on the studies collectively indicating the role of RBPs in oxidative stress and chronic inflammation as common pathogenic mechanisms shared by lung cancer and COPD.

Exhaled Nitric Oxide as Biomarker of Type 2 Diseases

Nitric oxide (NO) is a short-lived gas molecule which has been studied for its role as a signaling molecule in the vasculature and later, in a broader view, as a cellular messenger in many other biological processes such as immunity and inflammation, cell survival, apoptosis, and aging. Fractional exhaled nitric oxide (FeNO) is a convenient, easy-to-obtain, and non-invasive method for assessing active, mainly Th2-driven, airway inflammation, which is sensitive to treatment with standard anti-inflammatory therapy. Consequently, FeNO serves as a valued tool to aid the diagnosis and monitoring of several asthma phenotypes. More recently, FeNO has been evaluated in several other respiratory and/or immunological conditions, including allergic rhinitis, chronic rhinosinusitis with/without nasal polyps, atopic dermatitis, eosinophilic esophagitis, and food allergy. In this review, we aim to provide an extensive overview of the current state of knowledge about FeNO as a biomarker in type 2 inflammation, outlining past and recent data on the application of its measurement in patients affected by a broad variety of atopic/allergic disorders.

[Eosinophilic chronic obstructive pulmonary disease: A review]

Over the past decades, chronic obstructive pulmonary disease (COPD) has become a major public health problem due to increasing morbidity and mortality. COPD is characterized by airflow limitation due to inflammation of the bronchial tree and remodeling of the small airways. In 20-40% of patients with COPD, eosinophilic inflammation of the airways is observed, as in bronchial asthma. Eosinophilic COPD has recently been shown to be a distinct disease and is associated with more pronounced airway remodeling. Although the role of eosinophils in the pathogenesis of COPD is not fully understood, the level of eosinophils can be used in the prognosis and administration of corticosteroids, and their effectiveness is higher in eosinophilia. Currently, monoclonal antibodies directed against interleukins (IL-5, IL-4 and IL-13) or their receptors are being tested in the T2 endotype of COPD. This review focuses on the mechanisms of eosinophilia in COPD, the use of blood and sputum eosinophils as a biomarker, and the advisability of using monoclonal antibodies in the treatment of eosinophilic COPD.

Endoplasmic reticulum stress: a vital process and potential therapeutic target in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a chronic and progressive disease characterized by persistent respiratory symptoms and progressive airflow obstruction, has attracted extensive attention due to its high morbidity and mortality. Although the understanding of the pathogenesis of COPD has gradually increased because of increasing evidence, many questions regarding the mechanisms involved in COPD progression and its deleterious effects remain unanswered. Recent advances have shown the potential functions of endoplasmic reticulum (ER) stress in causing airway inflammation, emphasizing the vital role of unfolded protein response (UPR) pathways in the development of COPD.

METHODS

A comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original research articles and reviews related to ER stress, UPR, and COPD.

RESULTS

The common causes of COPD, namely cigarette smoke (CS) and air pollutants, induce ER stress through the generation of reactive oxygen species (ROS). UPR promotes mucus secretion and further plays a dual role in the cell apoptosis-autophagy axis in the development of COPD. Existing drug research has indicated the potential of UPR as a therapeutic target for COPD.

CONCLUSIONS

ER stress and UPR activation play significant roles in the etiology, pathogenesis, and treatment of COPD and discuss whether related genes can be used as biomarkers and therapeutic targets.

Genetic Variants of Adrenoceptors

Adrenoceptors are class A G-protein-coupled receptors grouped into three families (α1-, α2-, and β-adrenoceptors), each one including three members. All nine corresponding adrenoceptor genes display genetic variation in their coding and adjacent non-coding genomic region. Coding variants, i.e., nucleotide exchanges within the transcribed and translated receptor sequence, may result in a difference in amino acid sequence thus altering receptor function and signaling. Such variants have been intensely studied in vitro in overexpression systems and addressed in candidate-gene studies for distinct clinical parameters. In recent years, large cohorts were analyzed in genome-wide association studies (GWAS), where variants are detected as significant in context with specific traits. These studies identified two of the in-depth characterized 18 coding variants in adrenoceptors as repeatedly statistically significant genetic risk factors - p.Arg389Gly in the β1- and p.Thr164Ile in the β2-adrenoceptor, along with 56 variants in the non-coding regions adjacent to the adrenoceptor gene loci, the functional role of which is largely unknown at present. This chapter summarizes current knowledge on the two coding variants in adrenoceptors that have been consistently validated in GWAS and provides a prospective overview on the numerous non-coding variants more recently attributed to adrenoceptor gene loci.

Inhibition of oxidative stress by apocynin attenuated chronic obstructive pulmonary disease progression and vascular injury by cigarette smoke exposure

BACKGROUND AND PURPOSE

Cardiovascular disease affects up to half of the patients with chronic obstructive pulmonary disease (COPD), exerting deleterious impact on health outcomes and survivability. Vascular endothelial dysfunction marks the onset of cardiovascular disease. The present study examined the effect of a potent NADPH Oxidase (NOX) inhibitor and free-radical scavenger, apocynin, on COPD-related cardiovascular disease.

EXPERIMENTAL APPROACH

Male BALB/c mice were exposed to either room air (Sham) or cigarette smoke (CS) generated from 9 cigarettes·day-1 , 5 days a week for up to 24 weeks with or without apocynin treatment (5 mg·kg-1 ·day-1 , intraperitoneal injection).

KEY RESULTS

Eight-weeks of apocynin treatment reduced airway neutrophil infiltration (by 42%) and completely preserved endothelial function and endothelial nitric oxide synthase (eNOS) availability against the oxidative insults of cigarette smoke exposure. These preservative effects were maintained up until the 24-week time point. 24-week of apocynin treatment markedly reduced airway inflammation (reduced infiltration of macrophage, neutrophil and lymphocyte), lung function decline (hyperinflation) and prevented airway collagen deposition by cigarette smoke exposure.

CONCLUSION AND IMPLICATIONS

Limiting NOX activity may slow COPD progression and lower cardiovascular disease risk, particularly when signs of oxidative stress become evident.

Differences in the lipid metabolism profile and clinical characteristics between eosinophilic and non-eosinophilic acute exacerbation of chronic obstructive pulmonary disease

Objective: In this study, we aimed to investigate the differences in serum lipid metabolite profiles and their relationship with clinical characteristics between patients with eosinophilic and non-eosinophilic AECOPD. Methods: A total of 71 AECOPD patients were enrolled. Eosinophilic AECOPD was defined as blood EOS% ≥ 2% (n = 23), while non-eosinophilic AECOPD, as blood EOS< 2% (n = 48). Clinical data were collected, and serum lipid metabolism profiles were detected by liquid chromatography-mass spectrometry (LC-MS). The XCMS software package was used to pre-process the raw data, and then, lipid metabolite identification was achieved through a spectral match using LipidBlast library. Differences in lipid profiles and clinical features between eosinophilic and non-eosinophilic groups were analyzed by generalized linear regression. The least absolute shrinkage and selection operator (LASSO) was applied to screen the most characteristic lipid markers for the eosinophilic phenotype. Results: Eosinophilic AECOPD patients had less hypercapnic respiratory failures, less ICU admissions, a shorter length of stay in the hospital, and a lower fibrinogen level. In the lipid metabolism profiles, 32 significantly different lipid metabolites were screened through a t-test adjusted by using FDR (FDR-adjusted p < 0.05 and VIP> 1). Nine differential lipid metabolites were found to be associated with the three clinical features, namely, hypercapnia respiratory failure, ICU admission, and fibrinogen in further integration analysis. The species of triacylglycerol (TAG), phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and diacylglyceryl trimethylhomoserine (DGTS) were high in these eosinophilic AECOPD. The LASSO was applied, and three lipid metabolites were retained, namely, LPC (16:0), TAG (17:0/17:2/17:2), and LPC (20:2). The logistic regression model was fitted using these three markers, and the area under the ROC curve of the model was 0.834 (95% CI: 0.740-0.929). Conclusion: Patients with eosinophilic AECOPD had a unique lipid metabolism status. Species of TAGs and LPCs were significantly increased in this phenotype and were associated with better clinical outcomes.

Heme oxygenase-1 determines the cell fate of ferroptotic death of alveolar macrophages in COPD

Background

Despite an increasing understanding of chronic obstructive pulmonary disease (COPD) pathogenesis, the mechanisms of diverse cell populations in the human lung remain unknown. Using single-cell RNA sequencing (scRNA-Seq), we can reveal changes within individual cell populations in COPD that are important for disease pathogenesis and characteristics.

Methods

We performed scRNA-Seq on lung tissue obtained from donors with non-COPD and mild-to-moderate COPD to identify disease-related genes within different cell types. We testified the findings using qRT-PCR, immunohistochemistry, immunofluorescence and Western blotting from 25 additional subjects and RAW 264.7 macrophages. Targeting ferroptosis with the ferroptosis inhibitor ferrostatin-1, iron chelator deferoxamine or HO-1 inhibitor zinc protoporphyrin was administered in the experimental cigarette smoke COPD mouse model.

Results

We identified two populations of alveolar macrophages (AMs) in the human lung that were dysregulated in COPD patients. We discovered that M2-like AMs modulate susceptibility to ferroptosis by disrupting lipid and iron homeostasis both in vivo and in vitro. The discrepancy in sensitivity to ferroptosis can be determined and regulated by HO-1. In contrast, M1-like AMs showed the ability to attenuate oxidative stress and exert resistance to ferroptosis. In addition, the expression of genes within M2-like AMs is also involved in defects in phagocytosis and lysosome distortion. This ferroptotic phenotype was ameliorated by antiferroptotic compounds, iron chelators and HO-1 inhibitors. During COPD, the accumulation of lipid peroxidation drives ferroptosis-sensitive M2-like AMs, while M1-like AMs show characteristics of ferroptosis resistance. Ferroptotic M2 AMs lose their anti-inflammatory and repair functions but provoke inflammatory responses, resulting in consistent inflammation and tissue damage in the presence of M1 AMs in COPD.

Conclusion

Appropriate interventions in ferroptosis can reduce the occurrence of infections and acute onset, and delay the COPD process.

Clinical significance of serum levels of 14-3-3β protein in patients with stable chronic obstructive pulmonary disease

Nowadays, the diagnosis and treatment of COPD are often based on the results of lung function tests. Certain individuals, however, are not candidates for lung function testing due to pulmonary bullae, cardiac failure, low lung function, and other factors. Therefore, we evaluated whether serum tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein β (14-3-3β) could be a biomarker for the diagnosis of stable COPD patients. The expression of serum 14-3-3β protein was evaluated by an enzyme-linked immunosorbent assay. The association between its concentrations and clinical parameters of stable COPD patients were analyzed by correlation analysis and ROC curve. The results before propensity score matching (PSM) showed that serum 14-3-3β protein concentrations (ng/ml) in stable COPD patients were significantly higher than in healthy controls (P < 0.001). Furthermore, serum 14-3-3β protein concentrations were higher in GOLD 3&4 COPD patients compared with healthy participants, GOLD 1 and GOLD 2 COPD patients (P < 0.05), which shows that the concentration of 14-3-3β protein correlates with disease severity in stable COPD patients. After 1:1 PSM, there was also a statistically significant rise in 14-3-3 protein levels in stable COPD patients compared to healthy controls (P < 0.01). Serum 14-3-3β protein levels were positively correlated with blood neutrophil levels (P < 0.05), and negatively related to lung function parameters in stable COPD patients (P < 0.01). When the cutoff value was set at 29.53 ng/ml, the ROC curve yielded a sensitivity of 84.9% and a specificity of 68.3% for diagnosing stable COPD. The 14-3-3β protein may be a potential serum biomarker for the diagnosis of stable COPD patients, which is associated with disease severity, systemic inflammation, and small airway obstruction.

CC16 as an Inflammatory Biomarker in Induced Sputum Reflects Chronic Obstructive Pulmonary Disease (COPD) Severity

Purpose

The progression of an abnormal inflammatory response plays a crucial role in the lung function decline of chronic obstructive pulmonary disease (COPD) patients. Compared to serum biomarkers, inflammatory biomarkers in induced sputum would be a more reliable reflection of inflammatory processes in the airways.

Patients and Methods

A total of 102 COPD participants were divided into a mild-to-moderate group (FEV1%pred≥ 50%, n=57) and a severe-to-very-severe group (FEV1%pred<50%, n=45). We measured a series of inflammatory biomarkers in induced sputum and analyzed their association with lung function and SGRQ in COPD patients. To evaluate the relationship between inflammatory biomarkers and the inflammatory phenotype, we also analyzed the correlation between biomarkers and airway eosinophilic phenotype.

Results

We found increased mRNA levels of MMP9, LTB4R, and A1AR and decreased levels of CC16 mRNA in induced sputum in the severe-to-very-severe group. After adjustment for age, sex and other biomarkers, CC16 mRNA expression was positively associated with FEV1%pred (r=0.516, p=0.004) and negatively correlated with SGRQ scores (r=-0.3538, p=0.043). As previously known, decreased CC16 was related to the migration and aggregation of eosinophils in airway. It was also found that CC16 had a moderate negative correlation with the eosinophilic inflammation in airway (r=-0.363, p=0.045) in our COPD patients.

Conclusion

Low CC16 mRNA expression levels in induced sputum were associated with low FEV1%pred and a high SGRQ score in COPD patients. Sputum CC16 as a potential biomarker for predicting COPD severity in clinical practice might attribute to the involvement of CC16 in airway eosinophilic inflammation.

Stability of Blood Eosinophils in COPD with Multiple Acute Exacerbations Within 1 Year and Its Relationship with Prognosis

Background

The relationship between increased blood eosinophils (EOS) and the prognosis of patients with chronic obstructive pulmonary disease (COPD) remains controversial. We aimed to explore the stability of blood eosinophils in patients with multiple hospitalizations for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) over a 1-year period and its relationship with readmission rates and mortality.

Methods

Prospectively include patients with at least 2 hospitalizations for AECOPD in 1 year between June 2019 and December 2021. Using 150 cells/ul as the cut-off value, the study population was divided into EOS, non-EOS, and fluctuating groups based on the longitudinal stability of blood EOS. The relationship between blood EOS and readmission rate and mortality was analyzed according to the 6-month follow-up after hospital discharge.

Results

A total of 202 patients were included. 48, 108, and 46 patients were in the EOS, non-EOS, and fluctuating groups, respectively. The stability of blood EOS at 1 year was 77.2%. The risk of death was lower in the EOS group compared to the non-EOS group (HR=0.323, 95% CI 0.113-0.930, P =0.036). The risk of readmission was lower in both the EOS group (HR=0.486, 95% CI 0.256-0.923, P =0.027) and the non-EOS group (HR=0.575, 95% CI 0.347-0.954, P = 0.032) than in the fluctuating group.

Conclusion

The blood EOS of COPD patients is relatively stable over 1 year. Patients with consistently high blood EOS had a lower risk of all-cause mortality after discharge; patients with fluctuating blood EOS had a higher risk of readmission.

MicroRNAs in Kawasaki disease: An update on diagnosis, therapy and monitoring

Kawasaki disease (KD) is an acute autoimmune vascular disease featured with a long stage of febrile. It predominantly afflicts children under 5 years old and causes an increased risk of cardiovascular combinations. The onset and progression of KD are impacted by many aspects, including genetic susceptibility, infection, and immunity. In recent years, many studies revealed that miRNAs, a novel class of small non-coding RNAs, may play an indispensable role in the development of KD via differential expression and participation in the central pathogenesis of KD comprise of the modulation of immunity, inflammatory response and vascular dysregulation. Although specific diagnose criteria remains unclear up to date, accumulating clinical evidence indicated that miRNAs, as small molecules, could serve as potential diagnostic biomarkers and exhibit extraordinary specificity and sensitivity. Besides, miRNAs have gained attention in affecting therapies for Kawasaki disease and providing new insights into personalized treatment. Through consanguineous coordination with classical therapies, miRNAs could overcome the inevitable drug-resistance and poor prognosis problem in a novel point of view. In this review, we systematically reviewed the existing literature and summarized those findings to analyze the latest mechanism to explore the role of miRNAs in the treatment of KD from basic and clinical aspects retrospectively. Our discussion helps to better understand the pathogenesis of KD and may offer profound inspiration on KD diagnosis, treatment, and prognosis.

Characteristics of 12-Month Readmission for Hospitalized Patients with COPD: A Propensity Score Matched Analysis of Prospective Multicenter Study

Purpose

Hospitalization for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is considered as severe exacerbations. Readmission for severe exacerbations is a crucial event for COPD patients. However, factors associated with readmission for severe exacerbations are incomplete. The study aimed to investigate different characteristics between the severe and non-severe exacerbation groups.

Patients and Methods

Patients hospitalized for severe AECOPD were included in multi-centers, and their exacerbations in next 12 months after discharge were recorded. According to exacerbations, patients were separated into the severe-exacerbation group and the non-severe exacerbation group. Propensity-score matching (PSM) and multivariable analyses were performed to compare the baseline characteristics of two groups. The Hosmer-Lemeshow test and receiver operating characteristic curve were applied to evaluate how well the model could identify clusters.

Results

The cohort included 550 patients with severe AECOPD across 27 study centers in China, and 465 patients were finally analyzed. A total of 41.5% of patients underwent readmission for AECOPD within 1 year. There were no significant differences in baseline characteristics between groups after PSM. Severe exacerbations in the 12 months were related to some factors, eg, the duration of COPD (13 vs 8 years, P<0.001), the COPD Assessment Test (CAT) score (20 vs 17, P<0.001), the blood eosinophil percentage (1.5 vs 2.0, P<0.05), and their inhaler therapies. Patients readmitted with AECOPD had a longer time of diagnosis (≥9 years), more symptoms (CAT ≥10), and lower blood eosinophils (Eos <2%). A clinical model was derived to help identify patients at risk of readmission with severe exacerbations.

Conclusion

These analyses confirmed the relevance of COPD at admission with future severe exacerbations. A lower blood eosinophils percentage appears to be related to readmission when combined with clinical history. Further studies are needed to evaluate whether this study can predict the risk of exacerbations.

Different inhaled corticosteroid doses in triple therapy for chronic obstructive pulmonary disease: systematic review and Bayesian network meta-analysis

A systematic review and Bayesian network meta-analysis is necessary to evaluate the efficacy and safety of triple therapy with different doses of inhaled corticosteroids (ICS) in stable chronic obstructive pulmonary disease (COPD). We selected 26 parallel randomized controlled trials (41,366 patients) comparing triple therapy with ICS/long-acting beta-agonist (LABA), LABA/long-acting muscarinic antagonist (LAMA), and LAMA in patients with stable COPD for ≥ 12 weeks from PubMed, EMBASE, the Cochrane Library, and clinical trial registries (search from inception to June 30, 2022). Triple therapy with high dose (HD)-ICS exhibited a lower risk of total exacerbation in pre-specified subgroups treated for ≥ 48 weeks than that with low dose (LD)-ICS (odds ratio [OR] = 0.66, 95% credible interval [CrI] = 0.52–0.94, low certainty of evidence) or medium dose (MD)-ICS (OR = 0.66, 95% CrI = 0.51–0.94, low certainty of evidence). Triple therapy with HD-ICS exhibited a lower risk of moderate-to-severe exacerbation in pre-specified subgroups with forced expiratory volume in 1 s < 65% (OR = 0.6, 95% CrI = 0.37–0.98, low certainty of evidence) or previous exacerbation history (OR = 0.6, 95% CrI = 0.36–0.999, very low certainty of evidence) than triple therapy with MD-ICS. Triple therapy with HD-ICS may reduce acute exacerbation in patients with COPD treated with other drug classes including triple therapy with LD- or MD-ICS or dual therapies.

Combining single-cell RNA sequencing of peripheral blood mononuclear cells and exosomal transcriptome to reveal the cellular and genetic profiles in COPD

Background

It has been a long-held consensus that immune reactions primarily mediate the pathology of chronic obstructive pulmonary disease (COPD), and that exosomes may participate in immune regulation in COPD. However, the relationship between exosomes and peripheral immune status in patients with COPD remains unclear.

Methods

In this study, we sequenced plasma exosomes and performed single-cell RNA sequencing on peripheral blood mononuclear cells (PBMCs) from patients with COPD and healthy controls. Finally, we constructed competing endogenous RNA (ceRNA) and protein–protein interaction (PPI) networks to delineate the interactions between PBMCs and exosomes within COPD.

Results

We identified 135 mRNAs, 132 lncRNAs, and 359 circRNAs from exosomes that were differentially expressed in six patients with COPD compared with four healthy controls. Functional enrichment analyses revealed that many of these differentially expressed RNAs were involved in immune responses including defending viral infection and cytokine–cytokine receptor interaction. We also identified 18 distinct cell clusters of PBMCs in one patient and one control by using an unsupervised cluster analysis called uniform manifold approximation and projection (UMAP). According to resultant cell identification, it was likely that the proportions of monocytes, dendritic cells, and natural killer cells increased in the COPD patient we tested, meanwhile the proportions of B cells, CD4 + T cells, and naïve CD8 + T cells declined. Notably, CD8 + T effector memory CD45RA + (Temra) cell and CD8 + effector memory T (Tem) cell levels were elevated in patient with COPD, which were marked by their lower capacity to differentiate due to their terminal differentiation state and lower reactive capacity to viral pathogens.

Conclusions

We generated exosomal RNA profiling and single-cell transcriptomic profiling of PBMCs in COPD, described possible connection between impaired immune function and COPD development, and finally determined the possible role of exosomes in mediating local and systemic immune reactions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02182-8.

Relationship Between Blood Eosinophils and Systemic Corticosteroid Therapy in COPD Exacerbation

Purpose

Patients and Methods

Results

Conclusion

Multi-omics analyses of airway host-microbe interactions in chronic obstructive pulmonary disease identify potential therapeutic interventions

The mechanistic role of the airway microbiome in chronic obstructive pulmonary disease (COPD) remains largely unexplored. We present a landscape of airway microbe-host interactions in COPD through an in-depth profiling of the sputum metagenome, metabolome, host transcriptome and proteome from 99 patients with COPD and 36 healthy individuals in China. Multi-omics data were integrated using sequential mediation analysis, to assess in silico associations of the microbiome with two primary COPD inflammatory endotypes, neutrophilic or eosinophilic inflammation, mediated through microbial metabolic interaction with host gene expression. Hypotheses of microbiome-metabolite-host interaction were identified by leveraging microbial genetic information and established metabolite-human gene pairs. A prominent hypothesis for neutrophil-predominant COPD was altered tryptophan metabolism in airway lactobacilli associated with reduced indole-3-acetic acid (IAA), which was in turn linked to perturbed host interleukin-22 signalling and epithelial cell apoptosis pathways. In vivo and in vitro studies showed that airway microbiome-derived IAA mitigates neutrophilic inflammation, apoptosis, emphysema and lung function decline, via macrophage-epithelial cell cross-talk mediated by interleukin-22. Intranasal inoculation of two airway lactobacilli restored IAA and recapitulated its protective effects in mice. These findings provide the rationale for therapeutically targeting microbe-host interaction in COPD.

Blood Eosinophils and Exhaled Nitric Oxide: Surrogate Biomarkers of Airway Eosinophilia in Stable COPD and Exacerbation

In recent years, tremendous efforts have been devoted to characterizing the inflammatory processes in chronic obstructive pulmonary disease (COPD) in order to provide more personalized treatment for COPD patients. While it has proved difficult to identify COPD-specific inflammatory pathways, the distinction between eosinophilic and non-eosinophilic airway inflammation has gained clinical relevance. Evidence has shown that sputum eosinophil counts are increased in a subset of COPD patients and that these patients are more responsive to oral or inhaled corticosteroid therapy. Due to feasibility issues associated with sputum cell profiling in daily clinical practice, peripheral blood eosinophil counts and fractional exhaled nitric oxide levels have been evaluated as surrogate biomarkers for assessing the extent of airway eosinophilia in COPD patients, both in stable disease and acute exacerbations. The diagnostic value of these markers is not equivalent and depends heavily on the patient’s condition at the time of sample collection. Additionally, the sensitivity and specificity of these tests may be influenced by the patient’s maintenance treatment. Overall, eosinophilic COPD may represent a distinct disease phenotype that needs to be further investigated in terms of prognosis and treatment outcomes.

Sputum Cytokine Profiling in COPD: Comparison Between Stable Disease and Exacerbation

Purpose

Cytokines are extracellular signaling proteins that have been widely implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Here, we investigated cytokine expression both at the mRNA and protein level in the sputum of healthy individuals, stable COPD patients, and those experiencing a severe acute exacerbation (AECOPD) requiring hospitalization.

Patients and Methods

Sputum was collected in 19 healthy controls, 25 clinically stable COPD patients, and 31 patients with AECOPD. In AECOPD patients sample collection was performed both at the time of hospital admission and at discharge following treatment. Sputum supernatant was analyzed by an antibody microarray detecting 120 cytokines simultaneously, while the mRNA expression of 14 selected cytokines in sputum cells was investigated by real-time PCR (qPCR).

Results

Proteomic analysis identified interleukin (IL)-6 and growth-regulated oncogene (GRO)α as the only sputum cytokines that were differentially expressed between stable COPD patients and healthy controls. At the onset of AECOPD, several cytokines exhibited altered sputum expression compared to stable COPD. Recovery from AECOPD induced significant changes in the sputum cytokine protein profile; however, the length of hospitalization was insufficient for most cytokines to return to stable levels. With regard to gene expression analysis by qPCR, we found that bone morphogenetic protein (BMP)-4 was up-regulated, while IL-1α, monokine-induced by interferon-γ (MIG), and BMP-6 were down-regulated at the mRNA level in patients with AECOPD compared to stable disease.

Conclusion

The sputum cytokine signature of AECOPD differs from that of stable COPD. Protein level changes are asynchronous with changes in gene expression at the mRNA level in AECOPD. The observation that the levels of most cytokines do not stabilize with acute treatment of AECOPD suggests a prolonged effect of exacerbation on the status of COPD patients.

Impact of chronic obstructive pulmonary disease on short-term outcome in patients with ST-elevation myocardial infarction during COVID-19 pandemic: insights from the international multicenter ISACS-STEMI registry

Background

Chronic obstructive pulmonary disease (COPD) is projected to become the third cause of mortality worldwide. COPD shares several pathophysiological mechanisms with cardiovascular disease, especially atherosclerosis. However, no definite answers are available on the prognostic role of COPD in the setting of ST elevation myocardial infarction (STEMI), especially during COVID-19 pandemic, among patients undergoing primary angioplasty, that is therefore the aim of the current study.

Methods

In the ISACS-STEMI COVID-19 registry we included retrospectively patients with STEMI treated with primary percutaneous coronary intervention (PCI) between March and June of 2019 and 2020 from 109 high-volume primary PCI centers in 4 continents.

Results

A total of 15,686 patients were included in this analysis. Of them, 810 (5.2%) subjects had a COPD diagnosis. They were more often elderly and with a more pronounced cardiovascular risk profile. No preminent procedural dissimilarities were noticed except for a lower proportion of dual antiplatelet therapy at discharge among COPD patients (98.9% vs. 98.1%, P = 0.038). With regards to short-term fatal outcomes, both in-hospital and 30-days mortality occurred more frequently among COPD patients, similarly in pre-COVID-19 and COVID-19 era. However, after adjustment for main baseline differences, COPD did not result as independent predictor for in-hospital death (adjusted OR [95% CI] = 0.913[0.658–1.266], P = 0.585) nor for 30-days mortality (adjusted OR [95% CI] = 0.850 [0.620–1.164], P = 0.310). No significant differences were detected in terms of SARS-CoV-2 positivity between the two groups.

Conclusion

This is one of the largest studies investigating characteristics and outcome of COPD patients with STEMI undergoing primary angioplasty, especially during COVID pandemic. COPD was associated with significantly higher rates of in-hospital and 30-days mortality. However, this association disappeared after adjustment for baseline characteristics. Furthermore, COPD did not significantly affect SARS-CoV-2 positivity.

Trial registration number: NCT 04412655 (2nd June 2020).

Smoking Cessation in Mice Does Not Switch off Persistent Lung Inflammation and Does Not Restore the Expression of HDAC2 and SIRT1

Once COPD is established, pulmonary lesions can only progress and smoking cessation by itself is not sufficient to switch off persistent lung inflammation. Similarly, in former-smoker mice, neutrophil inflammation persists and lung lesions undergo progressive deterioration. The molecular mechanisms underlying disease progression and the inefficiency of smoking cessation in quenching neutrophilic inflammation were studied in male C57 Bl/6 mice after 6 months of rest from smoking cessation. As compared with the mice that continued to smoke, the former-smoker mice showed reduced expression of histone deacetylases HDAC2 and SIRT1 and marked expression of p-p38 MAPK and p-Ser10. All these factors are involved in corticosteroid insensitivity and in perpetuating inflammation. Former-smoker mice do show persistent lung neutrophilic influx and a high number of macrophages which account for the intense staining in the alveolar structures of neutrophil elastase and MMP-9 (capable of destroying lung scaffolding) and 8-OHdG (marker of oxidative stress). “Alarmins” released from necrotic cells together with these factors can sustain and perpetuate inflammation after smoking cessation. Several factors and mechanisms all together are involved in sustaining and perpetuating inflammation in former-smoker mice. This study suggests that a better control of COPD in humans may be achieved by precise targeting of the various molecular mechanisms associated with different phenotypes of disease by using a cocktail of drug active toward specific molecules.

Effects of inhaled corticosteroids (ICS) on lung microbiota and local immune response in long-term treatment of chronic obstructive pulmonary disease (COPD): utility of titration and therapeutic index

Administration of inhaled corticosteroids (ICS) is one of the most controversial issues in the treatment of stable chronic obstructive pulmonary disease (COPD). Associations between these drugs and increased incidence of severe pneumonia and other respiratory infections have already been reported in literature, as well as effects on the immune system and on the lung microbiota. ICS vary in their pharmacodynamic and pharmacokinetic properties, despite being widely considered therapeutically similar. The use of ICS requires, therefore, a deep knowledge of their pharmacokinetics and pharmacodynamics to obtain the maximum benefit and the least side effects. Defining new phenotypes-endotypes of COPD may lead to novel pharmacological and therapeutic scenarios while define the correct indications for prescription of ICS. Titration is certainly an important means by which these objectives can be achieved.

Airway Eosinophilia on Bronchoalveolar Lavage and the Risk of Exacerbations in COPD

The associations between airway eosinophilia, measured in sputum or peripheral blood, and acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are inconsistent. We therefore aimed to determine the association between eosinophilia in bronchoalveolar lavage (BAL) fluid and AECOPD in a clinical cohort. We analyzed differential cell counts from baseline BAL fluid in participants in the DISARM clinical trial (Clinicaltrials.gov #NCT02833480) and classified participants by the presence or absence of BAL eosinophilia (>1% of total leukocytes). We determined the association between BAL eosinophilia and AECOPD over 1 year of follow-up using negative binomial regression and Cox proportional hazards test. N = 63 participants were randomized, and N = 57 had BAL differential cell counts available. Participants with BAL eosinophilia (N = 21) had a significantly increased rate of acute exacerbations (unadjusted incidence rate ratio (IRR) 2.0, p = 0.048; adjusted IRR 2.24, p = 0.04) and a trend toward greater probability of acute exacerbation (unadjusted hazard ratio (HR) 1.74, p = 0.13; adjusted HR 2.3, p = 0.1) in the year of follow-up compared to participants without BAL eosinophilia (N = 36). These associations were not observed for BAL neutrophilia (N = 41 participants), BAL lymphocytosis (N = 27 participants) or peripheral blood eosinophilia at various threshold definitions (2%, N = 37; 3%, N = 27; 4%, N = 16). BAL may therefore be a sensitive marker of eosinophilic inflammation in the distal lung and may be of benefit for risk stratification or biomarker-guided therapy in COPD.

Inflammatory response in human lung cells stimulated with plasma from COPD patients

Background: Chronic obstructive pulmonary disease (COPD) is a condition resulting from a persistent inflammatory state in the airways even after smoking cessation. Intriguingly, the reasons behind this persistence of the inflammatory influx without smoking exposure have not been fully unraveled. We aimed to explore the hypothesis that systemic inflammation in COPD patients influences lung cell inflammatory response. Methods: We cultured human lung fibroblast and human airway epithelial cell lines with plasma from COPD patients (four emphysematous-COPD, four asthma-COPD overlap, four chronic bronchitis-COPD, and four bronchiectasis-COPD), and four smokers or ex-smokers without COPD as controls. We measured Interleukine-8 (IL-8), C-reactive protein (CRP) and matrix metalloproteinase-9 (MMP-9) in plasma and culture supernatants by ELISA. Results: Cells stimulated with plasma from COPD patients and control subjects produced higher CRP, IL-8 and MMP-9 levels, an increase for COPD in CRP(p=0.039) in epithelial cells and IL-8(p=0.039) in fibroblasts and decrease for MMP-9(p=0.039) in fibroblasts. The response was higher in epithelial cells for IL-8(p=0.003) and in fibroblasts for MMP-9(p=0.063). The plasma from chronic bronchitis and bronchiectasis phenotypes induced higher IL-8 in fibroblasts. Conclusions: Plasma from COPD patients increases the inflammatory response in lung epithelial cells and lung fibroblasts, with a different response depending on the cell type and clinical phenotype.

Angiogenesis, Lymphangiogenesis, and Inflammation in Chronic Obstructive Pulmonary Disease (COPD): Few Certainties and Many Outstanding Questions

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, predominantly affecting the lung parenchyma and peripheral airways, that results in progressive and irreversible airflow obstruction. COPD development is promoted by persistent pulmonary inflammation in response to several stimuli (e.g., cigarette smoke, bacterial and viral infections, air pollution, etc.). Angiogenesis, the formation of new blood vessels, and lymphangiogenesis, the formation of new lymphatic vessels, are features of airway inflammation in COPD. There is compelling evidence that effector cells of inflammation (lung-resident macrophages and mast cells and infiltrating neutrophils, eosinophils, basophils, lymphocytes, etc.) are major sources of a vast array of angiogenic (e.g., vascular endothelial growth factor-A (VEGF-A), angiopoietins) and/or lymphangiogenic factors (VEGF-C, -D). Further, structural cells, including bronchial and alveolar epithelial cells, endothelial cells, fibroblasts/myofibroblasts, and airway smooth muscle cells, can contribute to inflammation and angiogenesis in COPD. Although there is evidence that alterations of angiogenesis and, to a lesser extent, lymphangiogenesis, are associated with COPD, there are still many unanswered questions.

Immunophenotyping of Acute Inflammatory Exacerbations of Lung Injury Driven by Mutant Surfactant Protein-C: A Role for Inflammatory Eosinophils

Acute inflammatory exacerbations (AIEs) represent immune-driven deteriorations of many chronic lung conditions, including COPD, asthma, and pulmonary fibrosis (PF). The first line of therapy is represented by broad-spectrum immunomodulation. Among the several inflammatory populations mobilizing during AIEs, eosinophils have been identified as promising indicators of an active inflammatory exacerbation. To better study the eosinophil-parenchymal crosstalk during AIE-PF, this work leverages a clinically relevant model of inflammatory exacerbations triggered by inducible expression of a mutation in the alveolar epithelial type 2 cell Surfactant Protein-C gene [SP-C^I73T]. Unbiased single-cell sequencing analysis of controls and SP-C^I73T mutants at a time coordinated with peak eosinophilia (14 days) defined heightened inflammatory activation, chemotaxis, and survival signaling (IL-6, IL-4/13, STAT3, Glucocorticoid Receptor, mTOR, and MYC) in eosinophils. To study the impact of eosinophils in inflammatory exacerbations, the SP-C^I73T line was crossed with eosinophil lineage deficient mice (GATA1^Δdbl) to produce the SP-C^I73TGATA1^KO line. Time course analysis (7-42 days) demonstrated improved lung histology, survival, and reduced inflammation in SP-C^I73TGATA1^KO cohorts. Spectral flow cytometry of tissue digests confirmed eosinophil depletion in GATA1^KO mice and the absence of a compensatory shift in neutrophils and immature monocyte recruitment. Eosinophil deletion resulted in progressive monocyte-derived macrophage accumulation (14 days post-injury), combined with declines in CD3⁺CD4⁺ lymphocyte and B220⁺ B cell abundance. Histochemical analysis revealed atypical inflammatory cell activation in SP-C^I73TGATA1^KO mice, with reduced numbers of Arg-1⁺ and iNOS⁺ cells, but increases in tgfb1 mRNA expression in bronchoalveolar lavage cells and tissue. Dexamethasone treatment (1 mg/kg daily, i.p.) was utilized to investigate corticosteroid efficacy in highly eosinophilic exacerbations induced by mutant SP-C^I73T. Dexamethasone successfully reduced total and eosinophil (CD11b⁺SigF⁺CD11c^-) counts at 14 days and was linked to reduced evidence of structural damage and perivascular infiltrate. Together, these results illustrate the deleterious role of eosinophils in inflammatory events preceding lung fibrosis and demonstrate the efficacy of corticosteroid treatment in highly eosinophilic exacerbations induced by mutant SP-C^I73T.