Background As preterm birth is a risk factor for developing chronic lung disease later in life and has been associated with asthma-like symptoms, we hypothesised that preterm-born adults with and without a history of bronchopulmonary dysplasia (BPD) resemble patients with asthma with respect to altered mucin expression in the airways. Methods Bronchial biopsies were retrieved from 39 adults born very-to-extremely preterm (of which 22 had a history of BPD), 18 adults with mild allergic asthma and 24 healthy controls. Mucin (MUC) 5AC and MUC5B protein expressions were determined by immunohistochemistry and immunoelectron microscopy. Additionally, the percentage of goblet cells was estimated. Results MUC5AC expression and the percentage of goblet cells were lower in preterm-born adults than in asthma patients but did not markedly differ from those of healthy controls. In the preterm-born adults, MUC5AC expression correlated negatively with forced expiratory volume in 1 s to forced vital capacity ratio (FEV1/FVC) and positively with St George's Respiratory Questionnaire scores. Preterm-born adults with high MUC5AC expression had more bronchial hyperreactivity than those with low expression. MUC5B expression was lower in preterm-born adults with bronchial hyperreactivity and higher in those who reported having phlegm compared with those who did not have these signs. Conclusions Unlike patients with asthma, preterm-born adults with or without BPD do not exhibit increased MUC5AC expression compared with healthy controls. However, the associations of MUC5AC and MUC5B expression with lung function, symptoms and quality-of-life indices suggest a potential clinical role for these mucins in this population.

Abstract Sarcoidosis is a multisystem disorder that primarily affects the lungs and is characterizedby granulomatous inflammation. However, much of the underlying disease mechanisms remain poorly understood. Extracellular vesicles (EVs) are small membrane-bound particles released by all cells and carry various cargos including metabolites. They are involved in intercellular communication that can be dysregulated in diseases.This study characterizes the metabolic cargo of EVs isolated from bronchoalveolar lavage fluid (BALF), using liquid chromatography-mass spectrometry (LC-MS)-based metabolomic analysis, in patients with sarcoidosis (n=37), compared to healthy controls (n=10). Additionally, the sarcoidosis signature was compared to another pulmonary disorder, anti-synthetase syndrome (ASyS, n=10). Arachidonic acid (AA) results were verified by ELISA. A total of 1202 metabolites were detected, with 111 annotated ones further analyzed. EVs from sarcoidosis patients showed distinct metabolomic profiles compared to both ASyS patients and healthy controls, with 38 annotated metabolites differentially expressed in any of the groups. In both annotated and non-annotated data, sarcoidosis patients clustered separately from ASyS patients and healthy individuals. Furthermore, sarcoidosis patients clustered in 3 subgroups, whereof one was similar to ASyS patients and one stood out as showing higher cell counts in BALF. Higher AA levels were found in sarcoidosis patient EVs by LC-MS, and AA results were verified by ELISA. Our data show that BALF EV metabolites are disease-dependent and support the notion thatsarcoidosis patients should be further subgrouped for better diagnosis and treatment.

Abstract Bronchopulmonary dysplasia (BPD) in infancy is a risk factor for obstructive lung disease in adults. We hypothesized that adults born preterm and diagnosed with BPD have an altered lung architecture which is correlated to lung function impairment. Individuals from the LUNAPRE cohort (clinicaltrials.gov/ct2/show/ NCT02923648 ) were included: preterm born (gestational week <32) with (n=24) or without (n=23) a previous diagnosis of BPD, full term born with allergic asthma (n=22) and healthy volunteers (n=24). Inspiratory and expiratory HRCT scans were performed and interpreted by two expert reviewers in a blinded manner. Structural changes were scored and quantitative density measurements were analysed automatically using a dedicated post-processing workstation. The HRCT scores were significantly higher in the BPD group compared to the other groups (p<0.001) and had highest numbers in subjects diagnosed with severe BPD. Most common HRCT changes were small peripheral opacities. Hypoattenuation during inspiration was only observed in the BPD group. Architectural distortion was observed in 6/24 BPD and 2/23 premature without BPD. HRCT scores correlated to FEV 1 in a negative manner for preterm (p<0.001) and BPD (p<0.05) groups. Oxygen supplementation during the neonatal period correlated with HRCT score in a positive manner for preterm group (p<0.001). No differences in lung density were observed between the groups. Young adults previously diagnosed with BPD have structural changes on CT which correlate with airway obstruction. Severity of BPD at the diagnosis was associated with CT abnormalities in adulthood. HRCT changes in adults with BPD were correlated with spirometry findings.

Elevated troponin I (TnI) has been reported in patients with chronic obstructive pulmonary disease (COPD) without cardiovascular disease (CVD), suggesting non-ischaemic mechanisms. We assessed this association in a population-based cohort of 22 526 individuals without known CVD or significant coronary artery calcification. TnI showed no association with COPD (adjusted OR 0.87, 95% CI 0.60 to 1.26; highest category vs below limit of detection) or with forced expiratory volume in 1 s/forced vital capacity (adjusted difference 0.002, 95% CI -0.001 to 0.004). Median TnI was 2.2 ng/L in both obstructive and non-obstructive groups. These findings do not support a pulmonary source of TnI elevation in mild to moderate, stable COPD and suggest that TnI elevations should prompt cardiovascular evaluation rather than being attributed to pulmonary disease alone.

BackgroundInfluenza infection increases the risk of pneumonia and respiratory failure in chronic obstructive pulmonary disease (COPD) and mucins play an important role in pulmonary host defense.MethodsLower airway mucins were obtained from long-term smokers with and without COPD, pneumonia patients, and healthy never-smokers; oral MUC5B was obtained from a healthy never-smoker, and the ability of lower airway mucins and oral MUC5B to bind influenza A virus (H1N1 and H3N2) was investigated.ResultsLower airway mucins from long-term smokers with and without COPD, as well as the oral MUC5B, bound to H1N1. In contrast, all mucins, regardless of donors, bound to H3N2. Differences in binding were linked to more pronounced glycan sialylation in lower airway mucins from pneumonia patients and long-term smokers compared with healthy never-smokers. For lower airway mucins, the abundance of α2-6-linked NeuAc correlated with H1N1 binding, whereas the abundance of α2-3-linked NeuAc correlated with H3N2 binding. A neuraminidase inhibitor increased virus binding, even more so for H1N1 than for H3N2, resulting in the binding of both H1N1 and H3N2 to all mucins. The H1N1 neuraminidase cleaved α2-3- and α2-6-linked NeuAc to a similar degree, whereas the H3N2 neuraminidase mainly cleaved the α2-6-linked NeuAc. Mucins inhibited influenza A infection in a concentration-dependent manner in airway epithelial cells, although more so for H1N1 than for H3N2.ConclusionMucins inhibit influenza infection, and this effect depends on viral subtype. Neuraminidase inhibitors enable mucins with low sialic acid content to preserve their virus-binding ability, thereby underscoring their therapeutic potential.

OBJECTIVES:There is a lack of knowledge about whether occupational exposures increase the risk of emphysema, especially in never-smokers. Our objective was to determine if occupational exposures are associated with emphysema and impaired diffusing capacity. METHODS:In the Swedish CArdioPulmonary bioImage Study (SCAPIS), persons from the general population aged 50-64 answered a questionnaire and underwent CT of the lung as well as assessment of the diffusing capacity of their lungs for carbon monoxide (DLCO), presented as DLCO<lower limit of normal (LLN). Emphysema was defined as emphysema in any part of the lungs. Occupational exposures were assessed by a job exposure matrix based on longest held job. ORs with 95% CIs were calculated using logistic multivariable models. RESULTS:In this cross-sectional study (27 370 persons including 13 981 never-smokers), occupational exposure to inorganic dust was associated with emphysema (OR 1.25, 95% CI 1.07 to 1.47), also among never-smokers, (OR 1.46, 95% CI 1.00 to 2.11). There were associations with DLCO<LLN for occupational exposure to inorganic dust and vapour and gases. With all exposures in the same model, inorganic dust was associated with emphysema (OR 1.30, 95% CI 1.08 to 1.57), and vapour and gases were associated with DLCO<LLN (OR 1.17, 95% CI 1.00 to 1.38). In those with emphysema and impaired DLCO, there was an association with inorganic dust (OR 1.65, 95% CI 1.20 to 2.28), also among never-smokers (OR 3.79, 95% CI 1.35 to 10.63). CONCLUSIONS:Occupational exposures to inorganic dust are associated with emphysema. The association is stronger in those with the combination of emphysema and impaired DLCO indicating serious exposure effects in the alveoli.

Bronchiectasis is a chronic airway disease characterized by dysbiosis, persistent inflammation, and permanent structural airway damage. Neutrophilic inflammation is a key pathogenic feature, as indicated by enhanced neutrophil-derived proteases and formation of neutrophil extracellular traps (NETs), associated with poor prognosis. However, recent studies have identified an eosinophilic endotype in up to 30% of patients, characterized by higher levels of type 2 (T2) cytokines and fractional exhaled nitric oxide (FeNO). The role of T helper (Th) cells in the dysregulated inflammatory environment of bronchiectasis remains unclear. Evidence suggests that persistent bacterial infection can skew adaptive immunity from Th1 toward Th2 response, while the airway microbiome-IL-17 axis is also a critical regulator of chronic inflammation. T regulatory (Treg) cells have been shown to play a protective role against excessive chronic inflammation by modulating the function of several types of effector cells, including the Th17 subset. However, the capacity of this subset to delay or prevent disease progression remains to be determined Microbial dysbiosis, with loss of diversity and increased quantity of bacterial pathogens, may also be important for disease progression, and emerging evidence indicates that distinct inflammatory endotypes associate with specific microbiota alterations, especially in severe disease. In this review, we provide an overview of the immune cells and cytokine signaling that are involved in the pathogenesis of bronchiectasis. Additionally, we present the main endotypes of bronchiectasis and explore the relationships between the type of inflammation and alterations in microbiota, as well as the potential benefits of targeting specific pathophysiological mechanisms for the management of bronchiectasis. This review also examines how bacterial infection can shift adaptive immunity from Th1 toward Th2 responses, the role of the airway microbiome-IL-17 axis in chronic inflammation and the potential protective role of Treg cells against excessive inflammation. Novel therapeutic strategies are highlighted, with focus on targeting specific cytokine signaling pathways and restoring Th17/Treg balance These developments underscore a shift toward precision medicine in bronchiectasis, emphasizing the importance of identifying specific inflammatory endotypes to tailor treatment strategies effectively.

Rationale: Preterm-birth can lead to Bronchopulmonary Dysplasia (BPD), with survivors often suffering lifelong impairment of lung function, leading to a diagnosis of asthma. Despite this, the underlying disease mechanisms in these individuals remain poorly understood. Oxylipins, including eicosanoids, are important modulators of immune response and cell development in the lung by contributing to tissue remodeling and cell proliferation. They are also involved in regulation of inflammation which can play a critical role in conditions such as asthma and COPD. This study aimed to investigate lipid profiles in the lungs of BPD survivors compared to preterm-born without BPD, patients with asthma and healthy controls born at full-term, focusing on lipid dysregulation in the airways. Methods: Sphingolipids and oxylipins, were quantified using liquid chromatography-mass spectrometry (LC-MS) in bronchoalveolar lavage fluid (BALF) from 90 individuals in the LUNAPRE cohort (NCT02923648). LUNAPRE consists of four groups matched for sex and age (average age of 20), of whom 22 were patients with mild asthma born at-term (9 males, 13 females), 22 BPD survivors (11 males, 11 females), 24 healthy at-term controls (12 males, 12 females), and 22 preterm without BPD (10 males, 12 females). A total of 169 oxylipins and 129 sphingolipids were screened, of which 22 oxylipins and 44 sphingolipids met quality control criteria. Post-quantification and data-normalization, noise was reduced by identifying the lipids contributing most to the variance between each pair of groups. The elastic-net approach, which combines Lasso and Ridge Penalization, was employed to avoid discarding correlated lipids. Subsequently, Orthogonal Partial Least Squares with Discriminant Analysis (OPLS-DA) models were constructed using the identified lipids from the elastic-net method to identify the main lipid drivers of group differences. Results: Multivariate analysis revealed distinct sex-specific alterations in lipid profiles. Among female BPD survivors, oxylipins were key drivers of group separation, with elevated levels of 12-HHTrE and 9,10-EpOME compared to healthy controls. In males, sphingolipids were more discriminant, with increased levels of Cer(d18:1/16:0), Cer(d18:1/18:0), and DhCer(d18:0/16:0) in BPD survivors and patients with asthma compared to healthy controls. Additionally, Cer(d18:1/18:1) was elevated, while LacCer(d18:1/22:0) was decreased in male BPD survivors compared to all other male groups. Conclusions: These findings highlight significant sex-related alterations in the airway of BPD survivors that differ from those in mild asthma, providing a basis for further research into sex-specific and differing molecular mechanisms of different types of lung dysfunction and potential therapeutic targets which can advance the field of personalized medicine.

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.

Rationale Interleukin (IL)-38 is an anti-inflammatory cytokine in the IL-1 superfamily. Its production is upregulated in several chronic inflammatory disorders, acting as an endogenous antagonist of the neutrophil-mobilizing IL-36 cytokines. However, the role of IL-38 in the context of chronic obstructive pulmonary disease (COPD) remains largely unexplored. In this study, we aimed to determine whether systemic IL-38 concentrations are altered in COPD. Methods Patients with COPD (GOLD stages 2-4, groups A-E), as well as lung-healthy controls (LHC), were recruited at a tertiary clinical center. All subjects underwent pulmonary function tests (spirometry, plethysmography, and carbon monoxide diffusion capacity (DLCO)). Sarcopenia was assessed (hand grip strength test) and all COPD patients underwent chest imaging (X-ray or computed tomography (CT)). Emphysema was evaluated and graded in CT scans by a pulmonology specialist. IL-38 concentrations in serum were quantified by enzyme-linked immunosorbent assay (ELISA). Results Patients with COPD (n=25) comprised 60% females; a median age of 68 (64-73) years; 80% ex-smokers, 16% current smokers, and 4% never-smokers. Twenty percent were classified in GOLD stage 2, whereas 64% were classified in stage 3 and 8% in stage 4. Healthy subjects (n= 15) comprised 80% females; a median age of 42 (36-62) years; 68% never-smokers, and 33% ex-smokers. In the COPD group, 23 patients had a CT while two had an X-ray. Emphysema was present in a majority (78%), of which 30% were graded as severe. Serum IL-38 was markedly lower in the COPD group compared to the healthy group (Figure 1A). In contrast, within the COPD group, IL-38 concentrations were clearly higher in those with severe emphysema compared to those with mild or no emphysema (Figure 1B). IL-38 concentrations correlated with hand-grip strength in the entire (pooled) study population (Figure 1C), with a trend towards a similar correlation in the COPD group (n.s.). Conclusion The reduced systemic concentrations of IL-38 in the COPD group are suggestive of impaired systemic protection by this cytokine in COPD. Moreover, the positive correlation between IL-38 concentrations and hand-grip strength in the entire study population is compatible with a protective effect of IL-38 against sarcopenia. The enhanced concentrations of IL-38 among patients with severe emphysema in the COPD group are suggestive of a reactive but still protective role in this comorbidity. Taken together, our results motivate further study of a protective role IL-38 in COPD and emphysema to delineate its mechanism(s) of action.

Background:There is published evidence that a modest increase in blood eosinophils during stable COPD indicates future risk for exacerbations and a potential utility of inhaled corticosteroids. This has been perceived as an argument for targeting systemic eosinophil mobilization to prevent exacerbations in COPD, but there are no published data on systemic eosinophil mobilization during exacerbations in patients without allergy. Methods:We investigated long-term tobacco smokers (LTS: ≥10 pack-years) with COPD and chronic bronchitis (COPD-CB; GOLD stage 1-4; n = 47) but no allergy; LTS without COPD and CB (LTS; n = 10), and healthy never-smokers (HNS; n = 10) during stable disease for cross-sectional comparisons. For longitudinal comparisons, we followed the COPD-CB group for 15 months during stable disease and exacerbations, excluding samples affected by systemic corticosteroids. We quantified blood concentrations of eosinophils, the activity marker eosinophilic cationic protein (ECP) and the chemokine interleukin (IL)-4. Results:During stable disease, the concentrations of eosinophils were similar for the COPD-CB and the LTS group, although higher than in the HNS group. The concentrations of ECP and IL-4 were not markedly different in the COPD-CB and LTS groups either. During exacerbations, the concentrations of eosinophils, ECP and IL-4 were not further increased, and there was even a mathematical trend towards a decrease for these concentrations. Conclusion:The clinical evidence presented here suggests that, by average, there is no additional mobilization of eosinophils during exacerbations in patients with COPD and chronic bronchitis but no allergy. Thus, in this common phenotype, the immunological rationale for targeting systemic eosinophils during exacerbations remains unaccounted for, which motivates verification studies in large cohorts stratified for allergy and chronic bronchitis.

BACKGROUND:Low lung function has been consistently associated with increased cardiovascular disease (CVD) risk, with emerging evidence suggesting a potential causal relationship. However, underlying biological mechanisms remain unclear. AIM:To investigate relationships between CVD-associated plasma proteins and lung function. METHODS:We analysed plasma protein profiles in two Swedish population-based cohorts: the Swedish CArdioPulmonary bioImage Study (SCAPIS) (n = 4,982, mean age 57.6 years) as the discovery cohort and the SCAPIS pilot study (n = 1,054, mean age 57.7 years) for replication. Multiple linear regression models were used to assess associations between 92 CVD-associated proteins and z-scores of FEV1, FVC, and FEV1/FVC, adjusting for known confounders. P-values were corrected using the Benjamini-Hochberg method (5% FDR). Significantly associated proteins were validated in the replication cohort. RESULTS:A total of 69 proteins were associated with FEV1, 57 with FVC, and 9 with FEV1/FVC. Several inflammatory proteins and adipokines, including leptin, interleukin-6, fatty acid-binding protein (adipocyte), were consistently linked to lower lung function. Leptin had the strongest negative association (FEV1: β = -0.50, 95 % CI: [-0.69, -0.31], p < 0.001; FVC: β = -0.52, 95 % CI: [-0.68, -0.35], p < 0.001 per-SD increase). CONCLUSIONS:Multiple CVD-associated proteins, mainly reflecting inflammatory and metabolic processes, were associated with reduced FEV1 and FVC, supporting a link between systemic inflammation, adipokine metabolism and impaired lung function. Leptin had the strongest association, suggesting that its effects on lung function may extend beyond adiposity. Further research is needed to clarify the mechanisms driving these associations and to assess whether these proteins could serve as early biomarkers or intervention targets.

During exacerbations, patients with chronic obstructive pulmonary disease (COPD) are at risk for severe cardiovascular disease (CVD). Despite this, the available literature on systemic biomarkers of CVD during exacerbations is limited. In the present study, a proteomic approach was used to assess alterations in the concentrations of 177 biomarkers of CVD and inflammation in serum samples from 26 long-term smokers (LTS) with mild-to-severe COPD (GOLD stage 1-3) and chronic bronchitis (COPD-CB) but no allergy. These patients were followed for 60 weeks, and they all provided paired samples during stable disease and exacerbations. Serum samples from ten healthy non-smokers (HNS) and ten LTS without COPD or CB constituted controls. Of all the proteins analyzed, only chymotrypsin C (CTRC), oncostatin M (OSM), and matrix metalloproteinase 10 (MMP-10) displayed significantly altered concentrations during exacerbations in the COPD-CB group. Here, the concentrations of CTRC and OSM correlated with exacerbation severity, CRP, blood leukocytes, and other cardiovascular biomarkers. In contrast, the concentration of MMP-10 during stable disease correlated with blood eosinophil counts and exacerbation numbers. Finally, the concentrations of OSM and MMP-10 during stable disease correlated with blood leukocytes and tobacco load, respectively. Our study suggests that CTRC, OSM, and MMP-10 bear potential as cardiorespiratory biomarkers in patients with COPD and CB. Collectively, these biomarkers display substantial alterations during exacerbations and correlate with the severity and number of exacerbations. These results motivate prospective studies to determine the clinical utility of CTRC, OSM, and MMP-10 in assessing cardiorespiratory risk in patients with COPD.

Rationale The large number of COPD patients poses medical and economic challenges, creating increasing demand for diagnostic and prognostic tools to aid targeted treatment. Interleukin (IL)-26, a Th17-associated cytokine, plays unique roles in the lungs by facilitating directed neutrophil mobilization and exerting bactericidal effects.Constitutively produced by various cells in the lung, IL-26 is increased in the lower airways of smokers with COPD and displays a negative correlation with lung function. Here, we hypothesized that IL-26 in the nasal cavity reflects key aspects of clinical manifestations in COPD, constituting a convenient alternative sampling strategy for monitoring moderate and severe COPD patients. Methods COPD patients (n=25, 60% females; age 64-73 years; 80% ex-smokers, 16% current smokers, 4% never-smokers; 20% GOLD stage 2, 64% stage 3, 8% stage 4; 92% on inhaled corticosteroids) were recruited consecutively at Karolinska Severe COPD Center. Volunteers without lung disease were included as controls (n=15). All participants underwent spirometry with a reversibility test and chest imaging. Controls and two COPD patients received X-rays, while the remaining 23 COPD patients had computed tomography to assess emphysema, as evaluated by a pulmonologist. Questionnaires for symptoms and quality of life were employed. Nasal lavage (NAL) was performed with PBS to a recovery of 7mL and centrifuged to clear the fluid from cells and debris. Protein concentrations of IL-26 were quantified through ELISA (LOD = 6.6 pg/mL for serum, 125 pg/mL for NAL). Statistical analysis was performed in GraphPad Prism 10. Results Serum concentrations of IL-26 were detected in 11/15 controls and 7/25 COPD patients, with substantial differences between the two groups (25.96 pg/mL vs. 1,338 pg/mL in controls, p=0.02). In contrast, IL-26 concentrations in the nasal cavity were higher and detectable in all participants, but with similar levels in both groups (4,539 pg/mL in COPD patients vs 4,058 pg/mL in controls). NAL IL-26 concentrations were lower in the subgroup that presented emphysema (72% of patients) (Fig.1A). Nasal IL-26 concentrations displayed negative correlations with the COPD Assessment Test (Fig.1B) and the St. George Respiratory Questionnaire (Fig.1C) scores. Conclusion In the clinical setting at a tertiary center, a decreased systemic concentration of IL-26 may discriminate COPD patients from individuals without lung disease. In COPD patients, lower NAL IL-26 concentrations may indicate the presence of emphysema, heightened symptoms, and diminished quality of life. All these findings support further investigation of IL-26 as a biomarker among COPD patients in a clinical setting.