Chronic obstructive pulmonary disease (COPD) in women due to indoor biomass burning: a meta analysis

Chronic Obstructive Pulmonary Disease (COPD) is attributable to household air pollution and is known to increase the Disability Adjusted Life Years (DALYs), morbidity and mortality and women are most susceptible groups for the exposure. In order to understand the global risk among women with COPD due to exposure of household air pollutants, an evidence-based systematic review and meta-analysis was conducted. Meta regression analysis was carried out to identify potential sources of heterogeneity. The summary estimates of the included studies showed higher prevalence of COPD due to biomass fuel exposure in women. Clinical diagnosis has shown more risk of COPD prevalence compared to diagnosis based on spirometer test alone. However, the data between included studies for both clinical and spirometry-based studies showed higher heterogeneity. The present meta-data analysis has shown that household air pollutants may be a factor associated with increased risk of COPD in women.

Pristimerin alleviates cigarette smoke-induced inflammation in chronic obstructive pulmonary disease via inhibiting NF-κB pathway

Cigarette smoke (CS) is a risk factor for chronic obstructive pulmonary disease (COPD), which can exacerbate inflammation and oxidative stress. Pristimerin (Pris) is a natural compound with antioxidant and anti-inflammatory effects. We managed to evaluate the protective effects of Pris on CS-induced COPD. The CS-induced COPD mice model and cell model were constructed. The effects of Pris treatment on lung function, inflammatory cell infiltration, myeloperoxidase (MPO), and pathological changes of lung tissues in mice model were evaluated. The impacts of Pris treatment on inflammatory factors, chemokines, and oxidative stress parameters in mice lung tissues and cells were determined by kits. The viability of human bronchial epithelial cells after Pris treatment was tested by CCK-8. The activation of NF-κB pathway was confirmed by Western blot and immunofluorescence. CS treatment impaired lung function, reduced weight of mice, and enhanced inflammatory cell infiltration, MPO, and lung tissue damage, but these effects of CS were reversed by Pris treatment. Furthermore, Pris treatment downregulated the levels of malondialdehyde, IL-6, IL-1β, TNF-α, CXCL1, and CXLC2, but upregulated superoxide dismutase and catalase levels. Pris treatment could overturn CS-induced activation of the NF-κB pathway. Pris alleviates CS-induced COPD by inactivating NF-κB pathway.

Toxicological Mechanism of Individual Susceptibility to Formaldehyde-Induced Respiratory Effects

Understanding the mechanisms of individual susceptibility to exposure to environmental pollutants has been a challenge in health risk assessment. Here, an integrated approach combining a CRISPR screen in human cells and epidemiological analysis was developed to identify the individual susceptibility to the adverse health effects of air pollutants by taking formaldehyde (FA) and the associated chronic obstructive pulmonary disease (COPD) as a case study. Among the primary hits of CRISPR screening of FA in human A549 cells, HTR4 was the only gene genetically associated with COPD susceptibility in global populations. However, the association between HTR4 and FA-induced respiratory toxicity is unknown in the literature. Adverse outcome pathway (AOP) network analysis of CRISPR screen hits provided a potential mechanistic link between activation of HTR4 (molecular initiating event) and FA-induced lung injury (adverse outcome). Systematic toxicology tests (in vitro and animal experiments) were conducted to reveal the HTR4-involved biological mechanisms underlying the susceptibility to adverse health effects of FA. Functionality and enhanced expression of HTR4 were required for susceptibility to FA-induced lung injury, and FA-induced epigenetic changes could result in enhanced expression of HTR4. Specific epigenetic and genetic characteristics of HTR4 were associated with the progression and prevalence of COPD, respectively, and these genetic risk factors for COPD could be potential biomarkers of individual susceptibility to adverse respiratory effects of FA. These biomarkers could be of great significance for defining subpopulations susceptible to exposure to FA and reducing uncertainty in the next-generation health risk assessment of air pollutants. Our study delineated a novel toxicological pathway mediated by HTR4 in FA-induced lung injury, which could provide a mechanistic understanding of the potential biomarkers of individual susceptibility to adverse respiratory effects of FA.

Efficacy of ICS versus Non-ICS Combination Therapy in COPD: A Meta-Analysis of Randomised Controlled Trials

Background

Methods

Results

Conclusion

Elastase- and LPS-Exposed Cpa3Cre/+ and ST2-/- Mice Develop Unimpaired Obstructive Pulmonary Disease

IL-33 and its receptor ST2, as well as mast cells and their mediators, have been implicated in the development of chronic obstructive pulmonary disease (COPD). However, whether mast cells and the ST2 receptor play a critical role in COPD pathophysiology remains unclear. Here, we performed repeated intranasal administrations of porcine pancreatic elastase and LPS for four weeks to study COPD-like disease in wildtype, ST2-deficient, and Cpa3^Cre/+ mice, which lack mast cells and have a partial reduction in basophils. Alveolar enlargement and changes in spirometry-like parameters, e.g. increased dynamic compliance and decreased expiratory capacity, were evident one day after the final LPS challenge and worsened over time. The elastase/LPS model also induced mild COPD-like airway inflammation, which encompassed a transient increase in lung mast cell progenitors, but not in mature mast cells. While ST2-deficient and Cpa3^Cre/+ mice developed reduced pulmonary function uninterruptedly, they had a defective inflammatory response. Importantly, both ST2-deficient and Cpa3^Cre/+ mice had fewer alveolar macrophages, known effector cells in COPD. Elastase/LPS instillation in vivo also caused increased bronchiole contraction in precision cut lung slices challenged with methacholine ex vivo, which occurred in a mast cell-independent fashion. Taken together, our data suggest that the ST2 receptor and mast cells play a minor role in COPD pathophysiology by sustaining alveolar macrophages.

Differential Outcomes Following 4 Weeks of Aclidinium/Formoterol in Patients with COPD: A Reanalysis of the ACTIVATE Study

Rationale

It is difficult to predict the effects of long-acting bronchodilators (LABD) on lung function, exercise capacity and physical activity in patients with chronic obstructive pulmonary disease (COPD). Therefore, the multidimensional response to LABD was profiled in COPD patients participating in the ACTIVATE study and randomized to LABD.

Methods

In the ACTIVATE study, patients were randomized to aclidinium bromide/formoterol fumarate (AB/FF) or placebo for four weeks. The primary outcomes included (1) lung function as measured by functional residual capacity (FRC), residual volume (RV), and spirometric outcomes; (2) exercise performance as measured by a constant work rate cycle ergometry test (CWRT); and (3) physical activity (PA) using an activity monitor. Self-organizing maps (SOMs) were used to create an ordered representation of the patients who were randomly assigned to four weeks of AB/FF and cluster them into different outcome groups.

Results

A total of 250 patients were randomized to AB/FF (n = 126) or placebo (n = 124). Patients in the AB/FF group (39.6% women) had moderate-to-severe COPD, static hyperinflation (FRC: 151.4 (27.7)% predicted) and preserved exercise capacity. Six clusters with differential outcomes were identified. Patients in clusters 1 and 2 had significant improvements in lung function compared to the remaining AB/FF-treated patients. Patients in clusters 1 and 3 had significant improvements in CWRT time, and patients in clusters 2, 3 and 6 had significant improvements in PA compared to the remaining AB/FF-treated patients.

Conclusion

Individual responses to 4 weeks of AB/FF-treatment in COPD are differential and the degree of change differs across domains of lung function, exercise capacity and PA. These results indicate that clinical response to LABD therapy is difficult to predict and is non-linear, and show doctors that it is important to look at multiple outcomes simultaneously when evaluating the clinical response to LABD therapy.

Clinical Trial Registration

The original ACTIVATE study was registered on ClinicalTrials.gov, registration number NCT02424344.

A Pooled Analysis of Mortality in Patients with COPD Receiving Dual Bronchodilation with and without Additional Inhaled Corticosteroid

Background

Objective

Methods

Results

Conclusion

Benefit of Prompt versus Delayed Use of Single-Inhaler Fluticasone Furoate/Umeclidinium/Vilanterol (FF/UMEC/VI) Following a COPD Exacerbation

Purpose

Triple therapy (TT; inhaled corticosteroid, long-acting muscarinic antagonist, and long-acting β₂-agonist) is recommended for patients with chronic obstructive pulmonary disease (COPD) at risk of exacerbation, although the optimum timing of TT initiation remains unclear. This study evaluated the impact of prompt versus delayed initiation of single-inhaler TT (fluticasone furoate, umeclidinium, and vilanterol [FF/UMEC/VI]) following a COPD exacerbation.

Patients and Methods

This retrospective cohort study used data from the IQVIA PharMetrics^® Plus database. Patients initiating FF/UMEC/VI following a COPD exacerbation between September 18, 2017 and September 30, 2019 (exacerbation = index date) were categorized as prompt (within 30 days of index) or delayed (31–180 days after index) FF/UMEC/VI initiators. Patients were aged ≥40 years at index, had ≥12 months’ continuous health insurance coverage before index (baseline), and ≥6 months’ coverage after index (follow-up). Patients with a COPD exacerbation or claim for FF/UMEC/VI during baseline were excluded. Inverse probability weighting was used to adjust for differences in baseline characteristics between cohorts. Exacerbations (overall, moderate, and severe), healthcare costs, and readmissions were evaluated during follow-up.

Results

A total of 1904 patients (prompt: 529; delayed: 1375) were included. After weighting, baseline characteristics were well balanced between cohorts. Patients in the prompt cohort had significantly lower rates per person-year (PPY) of overall (0.98 vs 1.23; rate ratio [RR] [95% CI] = 0.79 [0.65–0.94], p = 0.004), moderate (0.86 vs 1.03; RR [95% CI] = 0.84 [0.69–0.99], p = 0.038), and severe (0.11 vs 0.20; RR [95% CI] = 0.57 [0.37–0.79], p = 0.002) exacerbations, compared with delayed initiators. Mean all-cause and COPD-related healthcare costs were significantly lower among prompt initiators (all-cause: $26,107 vs $32,400 PPY, p = 0.014; COPD-related: $12,694 vs $17,640 PPY, p = 0.002).

Conclusion

Prompt initiation of FF/UMEC/VI following a moderate or severe COPD exacerbation was associated with significant reductions in exacerbations and healthcare costs relative to delayed initiation.

Interclass Difference in Pneumonia Risk in COPD Patients Initiating Fixed Dose Inhaled Treatment Containing Extrafine Particle Beclometasone versus Fine Particle Fluticasone

Background

Inhaled corticosteroids (ICS) afford therapeutic benefits in some COPD patients, but their widespread use is cautioned due to an increased risk of developing pneumonia. Subclass variations exist, and the risk profile differs for individual ICS. Formulation particle size has been identified as a potential effect modifier. The present study compared the risk of pneumonia among new COPD users of fixed-dose combination inhalers containing fine-particle fluticasone (fp-FDC-F) versus extrafine particle beclometasone (ef-FDC-BDP).

Methods

A propensity matched historical cohort study was conducted using data from the Optimum Patient Care Research Database. COPD patients aged ≥40 years with ≥1 year of continuous medical data who initiated fp-FDC-F or ef-FDC-BDP were compared. The primary outcome was time to pneumonia event, as treated, using either sensitive (physician diagnosed) or specific (physician diagnosed and x-ray or hospital admission confirmed) definitions.

Results

A total of 13,316 patients were matched. Initiation of fp-FDC-F (mean dosage furoate 99 µg; propionate 710 µg) was associated with an increased risk of pneumonia versus ef-FDC-BDP (mean beclometasone dose 395 µg), irrespective of definition (sensitive HR 1.38 95% CI 1.14–1.68; specific HR 1.31 95% CI 1.05–1.62).

Conclusion

In the current investigation, we found that in comparison to extrafine beclomethasone, commencing a formulation containing fluticasone is associated with an increased risk of developing pneumonia. These observations support the idea that not all ICS are equal in their adverse effects and subclass variations exist and should be carefully considered in the treatment choice.

Risk factors in air pollution exposome contributing to higher levels of TNFα in COPD patients

BACKGROUND

Air pollutants are found associated with various health effects in chronic obstructive pulmonary patients. Given the complicate chemical components of air pollutants, it is not clear which components are the main risk factors for these health effects.

OBJECTIVES

Based on the COPD in Beijing (COPDB) study and exposome concept, we examined comprehensively the air pollution components to screen out high-risk factors for systemic inflammation of COPD patients.

METHODS

Concentrations of PM with aerodynamic diameter ≤ 2.5 μm (PM_2.5), ultrafine and accumulated-mode particles (UFPs and Acc), PM_2.5-contained carbonaceous components/elements/water soluble ions, gaseous pollutants, temperature, and relative humidity (RH) were continuously monitored around participants. Urinary polycyclic aromatic hydrocarbons (PAHs) and cotinine, and serum tumor necrosis factor α (TNFα) were measured from 53 COPD and 82 non-COPD participants. Lifestyle variables were recorded using follow-up questionnaire. Linear mixed effects (LME) models were used to assess the associations of TNFα differences with exposure to air pollutants, meteorological variations, and lifestyle.

RESULTS

In COPD patients, the associations of TNFα differences with exposure to ozone, Cd, UFPs, Acc, 2-hydroxydibenzofuran, temperature and RH parameters, and several elements in PM_2.5 were significant in certain time-windows. For example, per interquartile range (IQR) increase in average ozone concentration 14 d before visits was associated with 17.3% (95% confidence interval: 6.8%, 27.7%) TNFα difference. Associations between ozone, Cd, UFPs, Acc, the maximum value of RH, and 2-hydroxydibenzofuran exposure and TNFα differences remained robust in two-pollutant models, and contributed to 19.0%, 10.5%, 2.2%, 1.6%, 2.1%, and 1.5% TNFα differences, respectively. Among the high-risk factors for COPD patients, the responses to UFPs, Acc, and 2-hydroxydibenzofuran were not robust in non-COPD participants.

DISCUSSION

Ozone, Cd, UFPs, Acc, PAHs exposure and RH variation were high-risk factors of systemic inflammation for COPD patients, and the profile of high-risk factors were different from those in general population.

Air pollution-regulated E-cadherin mediates contact inhibition of proliferation via the hippo signaling pathways in emphysema

Air pollution has been linked to emphysema in chronic obstruction pulmonary disease (COPD). However, the underlying mechanisms in the development of emphysema due to air pollution remain unclear. The objective of this study was to investigate the role of components of the Hippo signaling pathway for E-cadherin-mediated contact inhibition of proliferation in the lungs after air pollution exposure. E-Cadherin-mediated contact inhibition of proliferation via the Hippo signaling pathway was investigated in Sprague-Dawley (SD) rats whole-body exposed to air pollution, and in alveolar epithelial A549 cells exposed to diesel exhaust particles (DEPs), E-cadherin-knockdown, and high-mobility group box 1 (HMGB1) treatment. Underlying epithelial differentiation, apoptosis, and senescence were also examined, and the interaction network among these proteins was examined. COPD lung sections were used to confirm the observations in rats. Expressions of HMGB1 and E-cadherin were negatively regulated in the lungs and A549 cells by air pollution, and this was confirmed by knockdown of E-cadherin and by treating A549 cells with HMGB1. Depletion of phosphorylated (p)-Yap occurred after exposure to air pollution and E-cadherin-knockdown, which resulted in decreases of SPC and T1α. Exposure to air pollution and E-cadherin-knockdown respectively downregulated p-Sirt1 and increased p53 levels in the lungs and in A549 cells. Moreover, the protein interaction network suggested that E-cadherin is a key activator in regulating Sirt1 and p53, as well as alveolar epithelial cell differentiation by SPC and T1α. Consistently, downregulation of E-cadherin, p-Yap, SPC, and T1α was observed in COPD alveolar regions with particulate matter (PM) deposition. In conclusion, our results indicated that E-cadherin-mediated cell-cell contact directly regulates the Hippo signaling pathway to control differentiation, cell proliferation, and senescence due to air pollution. Exposure to air pollution may initiate emphysema in COPD patients.

Beyond Dual Bronchodilation – Triple Therapy, When and Why

Although pharmacological treatment of COPD is codified in different guidelines and strategy documents, there is abundant evidence of discrepancy between what they suggest and what health professionals prescribe, especially in low-risk groups where there is widespread overprescription of triple therapy. It is therefore necessary to clarify when the use of triple therapy is indicated in COPD patients and when it is preferable to maintain treatment with dual bronchodilation. In this article, we discuss our views based on our experience and what is reported in the literature and try to give answers to these two questions. The evidence generated by pivotal RCTs supports the use of triple therapy in patients who present for the first time and have severe airway obstruction, are symptomatic, have had frequent moderate or severe exacerbations in the previous year, and have peripheral eosinophilia. However, it is difficult to determine whether step-up is useful in all other cases because the available data are quite conflicting. It is likely that the inconsistency in the information generated by the various available studies may explain the prescribing behaviour of many physicians who do not adhere to recommendations of guidelines and strategies. However, it is necessary to establish whether and when the addition of an ICS to the LAMA/LABA combination is effective, to determine whether triple therapy can induce an additional clinical benefit over dual bronchodilation, irrespective of a preventive effect on COPD exacerbations, to establish its value, and to examine whether cost differences can support the use of triple therapy over combined LAMA/LABA therapy in real life.

Development and multimodal characterization of an elastase-induced emphysema mouse disease model for the COPD frequent bacterial exacerbator phenotype

Chronic obstructive pulmonary disease (COPD) patients undergo infectious exacerbations whose frequency identifies a clinically meaningful phenotype. Mouse models have been mostly used to separately study both COPD and the infectious processes, but a reliable model of the COPD frequent exacerbator phenotype is still lacking. Accordingly, we first established a model of single bacterial exacerbation by nontypeable Haemophilus influenzae (NTHi) infection on mice with emphysema-like lesions. We characterized this single exacerbation model combining both noninvasive in vivo imaging and ex vivo techniques, obtaining longitudinal information about bacterial load and the extent of the developing lesions and host responses. Bacterial load disappeared 48 hours post-infection (hpi). However, lung recovery, measured using tests of pulmonary function and the disappearance of lung inflammation as revealed by micro-computed X-ray tomography, was delayed until 3 weeks post-infection (wpi). Then, to emulate the frequent exacerbator phenotype, we performed two recurrent episodes of NTHi infection on the emphysematous murine lung. Consistent with the amplified infectious insult, bacterial load reduction was now observed 96 hpi, and lung function recovery and disappearance of lesions on anatomical lung images did not happen until 12 wpi. Finally, as a proof of principle of the use of the model, we showed that azithromycin successfully cleared the recurrent infection, confirming this macrolide utility to ameliorate infectious exacerbation. In conclusion, we present a mouse model of recurrent bacterial infection of the emphysematous lung, aimed to facilitate investigating the COPD frequent exacerbator phenotype by providing complementary, dynamic information of both infectious and inflammatory processes.

Drosophila Trachea as a Novel Model of COPD

COPD, a chronic obstructive pulmonary disease, is one of the leading causes of death worldwide. Clinical studies and research in rodent models demonstrated that failure of repair mechanisms to cope with increased ROS and inflammation in the lung leads to COPD. Despite this progress, the molecular mechanisms underlying the development of COPD remain poorly understood, resulting in a lack of effective treatments. Thus, an informative, simple model is highly valued and desired. Recently, the cigarette smoke-induced Drosophila COPD model showed a complex set of pathological phenotypes that resemble those seen in human COPD patients. The Drosophila trachea has been used as a premier model to reveal the mechanisms of tube morphogenesis. The association of these mechanisms to structural changes in COPD can be analyzed by using Drosophila trachea. Additionally, the timeline of structural damage, ROS, and inflammation can be studied in live organisms using fluorescently-tagged proteins. The related function of human COPD genes identified by GWAS can be screened using respective fly homologs. Finally, the Drosophila trachea can be used as a high-throughput drug screening platform to identify novel treatments for COPD. Therefore, Drosophila trachea is an excellent model that is complementary to rodent COPD models.

Isoforskolin, an adenylyl cyclase activator, attenuates cigarette smoke-induced COPD in rats

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by limited airflow due to pulmonary and alveolar abnormalities from exposure to cigarette smoke (CS). Current therapeutic drugs are limited and the development of novel treatments to prevent disease progression is challenging. Isoforskolin (ISOF) from the plant Coleus forskohlii is an effective activator of adenylyl cyclase (AC) isoforms. Previously we found ISOF could attenuate acute lung injury in animal models, while the effect of ISOF on COPD has not been elucidated.

PURPOSE

In this study, we aimed to evaluate the efficacy of ISOF on COPD and reveal its potential mechanisms.

METHODS

A rat model of COPD was established by long-term exposure to CS, then the rats were orally administered with ISOF (0.5, 1 and 2 mg/kg). The pulmonary function, lung morphology, inflammatory cells and cytokines in serum or bronchoalveolar lavage fluid (BALF) were evaluated. Transcriptomics, proteomics and network pharmacology analysis were utilized to identify potential mechanisms of ISOF. Droplet digital PCR was used to detect the mRNA expression of AC1-10 in donor lung tissues. AC activation was determined in recombinant human embryonic kidney 293 (HEK293) cells stably expressing human AC isoforms. In addition, ISOF caused trachea relaxation ex vivo were assessed in isolated trachea rings from guinea pigs.

RESULTS

ISOF significantly ameliorated pathological damage of lung tissue and improved pulmonary function in COPD rats. ISOF treatment decreased the number of inflammatory cells in peripheral blood, and also the levels of pro-inflammatory cytokines in serum and BALF. Consistent with omics-based analyses, ISOF markedly downregulated the mTOR level in lung tissue. Flow cytometry analysis revealed that ISOF treatment reduced the ratio of Th17/Treg cells in peripheral blood. Furthermore, the expression levels of AC1 and AC2 are relatively higher than other AC isoforms in normal lung tissues, and ISOF could potently activate AC1 and AC2 in vitro and significantly relax isolated guinea pig trachea.

CONCLUSION

Collectively, our studies suggest that ISOF exerts its anti-COPD effect by improving lung function, anti-inflammation and trachea relaxation, which may be related to AC activation, mTOR signaling and Th17/Treg balance.

Association between exposure to polycyclic aromatic hydrocarbons and lipid peroxidation in patients with chronic obstructive pulmonary disease

Polycyclic aromatic hydrocarbons (PAHs) are toxic airborne pollutants and may cause adverse effects at high level of oxidative stress. Here we hypothesized that individuals with impaired lung function are susceptible to PAHs associated oxidative damage. Hence, we carried out a panel study and conducted four follow-up visits on 40 chronic obstructive pulmonary disease (COPD) patients and 75 healthy controls. Hydroxylated PAHs (OH-PAHs) and malonaldehyde (MDA) were measured in urine as exposure and oxidative stress markers, respectively, which showed significant association in all participants. Quantitatively, a 1-fold increase in OH-PAHs was associated with a 4.1-15.1% elevation of MDA. The association between OH-PAHs and MDA levels became stronger in participants with impaired lung function. For 1% decrease of FEV1/FVC, the increase of MDA associated with a 1-fold increase in OH-PAHs was up to 0.49%, suggesting an increased susceptibility to PAH-induced oxidative damage in individuals with worse lung function. This study observed that impaired lung function modified the association between PAH exposure and oxidative damage, which might accelerate the aggravation of COPD, and therefore highlighted the necessity of protection measures to decrease the additional adverse effects of air pollution exposure. CAPSULE: Individuals with worse lung function may be more susceptible to PAH-induced lipid peroxidation.

Interactions of nasal epithelium with macrophages and dendritic cells variously alter urban PM-induced inflammation in healthy, asthma and COPD

Urban particulate matter (UPM) is an important trigger of airway inflammation. The cross-talk between the external and internal matrix in the respiratory tract occurs due to the transepithelial network of macrophages/dendritic cells. This study characterized the immune processes induced by the epithelium after UPM exposure in special regard to interactions with monocyte-derived dendritic cells (moDCs) and monocyte-derived macrophages (moMφs) in obstructive lung diseases. A triple-cell co-culture model (8 controls, 10 asthma, and 8 patients with COPD) utilized nasal epithelial cells, along with moMφs, and moDCs was exposed to UPM for 24 h. The inflammatory response of nasal epithelial cells to UPM stimulation is affected differently by cell-cell interactions in healthy people, asthma or COPD patients of which the interactions with DCs had the strongest impact on the inflammatory reaction of epithelial cells after UPM exposure. The epithelial remodeling and DCs dysfunction might accelerate the inflammation after air pollution exposure in asthma and COPD.

Chemical constituents and sources of indoor PM2.5 and cardiopulmonary function in patients with chronic obstructive pulmonary disease: Estimation of individual and joint effects

BACKGROUND

The cardiopulmonary effects of chemical constituents and sources of indoor fine particulate matter (PM_2.5) remain unclear.

OBJECTIVES

To examine the individual and joint effects of constituents of indoor PM_2.5 on cardiopulmonary function of patients with chronic obstructive pulmonary disease (COPD) and the role of identified sources.

METHODS

This panel study recruited 43 stable COPD patients from November 2015 to May 2016 in Beijing, China. Daily indoor and outdoor PM_2.5 were collected for five consecutive days simultaneously. Twenty-four elements were measured and principal component analysis was used for source appointment. Pulmonary function and blood pressure (BP) were also measured at daily visit. The linear mixed-effect models were used to estimate the effect of each constituent and source. Bayesian kernel machine regression (BKMR) models were used to estimate the overall effect of all measured constituents.

RESULTS

The combustion, indoor soil/dust and road dust sources were identified as the main sources of indoor PM_2.5 and combustion sources contributed over 40% during the heating season. Most constituents were significantly associated with elevated BP of COPD patients and the joint effects of mixed exposures were also significant especially during the heating season. Most associations of chemical constituents with pulmonary function were negative but not statistically significant during the heating season, as was the joint effect. Few associations were observed during the non-heating season. Further, we observed combustion sources throughout the study period and road dust sources during the heating season were significantly associated with increased BP but not decreased pulmonary function.

CONCLUSION

The combustion and road dust sources and their related constituents of indoor PM_2.5 could cause adverse effects on cardiovascular function of COPD patients especially during the heating season, but the effect on pulmonary function still needs to be further studied.

Mucus Plugs and Emphysema in the Pathophysiology of Airflow Obstruction and Hypoxemia in Smokers

Rationale: The relative roles of mucus plugs and emphysema in mechanisms of airflow limitation and hypoxemia in smokers with chronic obstructive pulmonary disease (COPD) are uncertain.Objectives: To relate image-based measures of mucus plugs and emphysema to measures of airflow obstruction and oxygenation in patients with COPD.Methods: We analyzed computed tomographic (CT) lung images and lung function in participants in the Subpopulations and Intermediate Outcome Measures in COPD Study. Radiologists scored mucus plugs on CT lung images, and imaging software automatically quantified emphysema percentage. Unadjusted and adjusted relationships between mucus plug score, emphysema percentage, and lung function were determined using regression.Measurements and Main Results: Among 400 smokers, 229 (57%) had mucus plugs and 207 (52%) had emphysema, and subgroups could be identified with mucus-dominant and emphysema-dominant disease. Only 33% of smokers with high mucus plug scores had mucus symptoms. Mucus plug score and emphysema percentage were independently associated with lower values for FEV1 and peripheral oxygen saturation (P < 0.001). The relationships between mucus plug score and lung function outcomes were strongest in smokers with limited emphysema (P < 0.001). Compared with smokers with low mucus plug scores, those with high scores had worse COPD Assessment Test scores (17.4 ± 7.7 vs. 14.4 ± 13.3), more frequent annual exacerbations (0.75 ± 1.1 vs. 0.43 ± 0.85), and shorter 6-minute-walk distance (329 ± 115 vs. 392 ± 117 m) (P < 0.001).Conclusions: Symptomatically silent mucus plugs are highly prevalent in smokers and independently associate with lung function outcomes. These data provide rationale for targeting patients with mucus-high/emphysema-low COPD in clinical trials of mucoactive treatments.Clinical trial registered with www.clinicaltrials.gov (NCT01969344).

Artesunate ameliorates cigarette smoke-induced airway remodelling via PPAR-γ/TGF-β1/Smad2/3 signalling pathway

BACKGROUND

Airway remodelling is the major pathological feature of chronic obstructive pulmonary disease (COPD), and leads to poorly reversible airway obstruction. Current pharmacological interventions are ineffective in controlling airway remodelling. In the present study, we investigated the potential role of artesunate in preventing and treating airway remodelling and the underlying molecular mechanisms in vitro and in vivo.

METHODS

A COPD rat model was established by cigarette smoke (CS) exposure. After 12 weeks of artesunate treatment, pathological changes in the lung tissues of COPD rats were examined by ELISA and histochemical and immunohistochemical staining. A lung functional experiment was also carried out to elucidate the effects of artesunate. Human bronchial smooth muscle (HBSM) cells were used to clarify the underlying molecular mechanisms.

RESULTS

Artesunate treatment inhibited CS-induced airway inflammation and oxidative stress in a dose-dependent manner and significantly reduced airway remodelling by inhibiting α-smooth muscle actin (α-SMA) and cyclin D1 expression. PPAR-γ was upregulated and TGF-β1/Smad2/3 signalling was inactivated by artesunate treatment in vivo and in vitro. Furthermore, PPAR-γ knockdown by siRNA transfection abolished artesunate-mediated inhibition of HBSM cell proliferation by activiting the TGF-β1/Smad2/3 signalling pathway and downregulating the expression of α-SMA and cyclin D1 in HBSM cells.

CONCLUSIONS

These findings suggest that artesunate could be used to treat airway remodelling by regulating PPAR-γ/TGF-β1/Smad signalling in the context of COPD.

The burden of sulfur dioxide pollution on years of life lost from chronic obstructive pulmonary disease: A nationwide analysis in China

BACKGROUND

Sulfur dioxide (SO₂) is one of the major gaseous pollutants in China and other developing countries. Few multicity studies have been done to examine the short-term effect of SO₂ on cause-specific years of life lost (YLL). This study was designed to investigate the burden of chronic obstructive pulmonary disease (COPD) associated with SO₂ exposure.

METHODS

A 5-year time-series study was conducted in 48 Chinese cities from 2013 to 2017. Generalized additive models were first used to estimate the city-specific relationship. Then, random-effects meta-analyses were applied to pool the estimates. Furthermore, the roles of potential modifiers and the related economic loss estimated by the method of value per statistical life year were also evaluated.

RESULTS

The annual mean concentration of SO₂ was 27.1 μg/m³. A 10 μg/m³ increase in 4-day moving average (lag03) of SO₂ concentration was associated with 0.83% (95% CI: 0.13%, 1.53%) relative increment in YLL from COPD, and relevant percent change of mortality was 0.78% (95% CI: 0.16%, 1.41%). Moreover, a significantly higher effect was observed in the warm season, particularly in the south region. SO₂ exposure was estimated to account for 1.89% of the total economic loss due to YLL from COPD.

CONCLUSIONS

Our findings showed a positive association between short-term exposure to SO₂ and YLL from COPD and highlighted the importance of continuous control of SO₂ pollution to reduce corresponding attributable disease burden.

Impact of long-term exposure to ambient air pollution on the incidence of chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND

It is well known that air pollution causes respiratory morbidity and mortality by inducing airway inflammation. However, whether long-term exposure to air pollution is associated with increased incidence of chronic obstructive pulmonary disease (COPD) is controversial.

METHODS

We conducted a systematic review and meta-analysis with a random-effects model to calculate the pooled risk estimates of COPD development per 10 μg/m³ increase in individual air pollutants. PubMed, Embase, and Cochrane Library were searched from the date of their inception to August 2019 to identify long-term (at least three years of observation) prospective longitudinal studies that reported the risk of COPD development due to exposure to air pollutants. The air pollutants studied included particulate matter (PM_2.5 and PM₁₀) and nitrogen dioxide (NO₂).

RESULTS

Of the 436 studies identified, seven met our eligibility criteria. Among the seven studies, six, three, and five had data on PM_2.5, PM₁₀, and NO₂, respectively. The meta-analysis results showed that a 10 μg/m³ increase in PM_2.5 is associated with increased incidence of COPD (pooled HR 1.18, 95% CI 1.13-1.23). We also noted that a 10 μg/m³ increase in NO₂ is marginally associated with increased incidence of COPD (pooled HR 1.07, 95% CI 1.00-1.16). PM₁₀ seems to have no significant impact on the incidence of COPD (pooled HR 0.95, 95% CI 0.83-1.08), although the number of studies was too small. Meta-regression analysis found no significant effect modifiers.

CONCLUSIONS

Long-term exposure to PM_2.5 and NO₂ can be associated with increased incidence of COPD.

Reducing and managing chronic obstructive pulmonary disease exacerbations with tiotropium + olodaterol

OBJECTIVE

The aim of this study was to review clinical evidence supporting the use of fixed-dose combination of tiotropium and olodaterol, a long-acting muscarinic antagonist (LAMA) and a long-acting β₂-agonist (LABA), respectively, as the initial and follow-up treatment choice in patients with chronic obstructive pulmonary disease (COPD) as per Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2020 recommendations-the impact of this treatment strategy on the reduction in the risk of exacerbations-and the importance of early therapeutic interventions.

METHODS

For this narrative review, the available literature was searched to identify studies including patients with COPD receiving tiotropium and olodaterol as either monotherapy or combination therapy and studies including patients with COPD receiving inhaled corticosteroids (ICS) in addition to long-acting bronchodilators. Relevant studies were included in the review.

RESULTS

Patients with COPD are often prescribed ICS therapy, which, when used over a long term, can be associated with local and systemic adverse effects. The GOLD 2020 report recommends dual bronchodilator therapy as both an initial and follow-up treatment option. A LABA + LAMA combination is mechanistically synergistic, and cumulative evidence surrounding the efficacy and safety of fixed-dose combination of tiotropium and olodaterol supports therapeutic advantages over monotherapy in most patients with COPD.

CONCLUSIONS

The early stages of COPD may represent a "window of therapeutic opportunity" during which initiation of tiotropium and olodaterol dual bronchodilator therapy may improve lung function and quality of life and reduce exacerbations in patients with COPD.

Distinguishing Smoking-Related Lung Disease Phenotypes Via Imaging and Molecular Features

BACKGROUND

Chronic tobacco smoke exposure results in a broad range of lung pathologies including emphysema, airway disease and parenchymal fibrosis as well as a multitude of extra-pulmonary comorbidities. Prior work using CT imaging has identified several clinically relevant subgroups of smoking related lung disease, but these investigations have generally lacked organ specific molecular correlates.

RESEARCH QUESTION

Can CT imaging be used to identify clinical phenotypes of smoking related lung disease that have specific bronchial epithelial gene expression patterns to better understand disease pathogenesis?

STUDY DESIGN AND METHODS

Using K-means clustering, we clustered participants from the COPDGene study (n = 5,273) based on CT imaging characteristics and then evaluated their clinical phenotypes. These clusters were replicated in the Detection of Early Lung Cancer Among Military Personnel (DECAMP) cohort (n = 360), and were further characterized using bronchial epithelial gene expression.

RESULTS

Three clusters (preserved, interstitial predominant and emphysema predominant) were identified. Compared to the preserved cluster, the interstitial and emphysema clusters had worse lung function, exercise capacity and quality of life. In longitudinal follow-up, individuals from the emphysema group had greater declines in exercise capacity and lung function, more emphysema, more exacerbations, and higher mortality. Similarly, genes involved in inflammatory pathways (tumor necrosis factor-α, interferon-β) are more highly expressed in bronchial epithelial cells from individuals in the emphysema cluster, while genes associated with T-cell related biology are decreased in these samples. Samples from individuals in the interstitial cluster generally had intermediate levels of expression of these genes.

INTERPRETATION

Using quantitative CT imaging, we identified three groups of individuals in older ever-smokers that replicate in two cohorts. Airway gene expression differences between the three groups suggests increased levels of inflammation in the most severe clinical phenotype, possibly mediated by the tumor necrosis factor-α and interferon-β pathways.

CLINICAL TRIAL REGISTRATION

COPDGene (NCT00608764), DECAMP-1 (NCT01785342), DECAMP-2 (NCT02504697).