The Relationship between Airway Inflammation and Exacerbation in Chronic Obstructive Pulmonary Disease

Sources, trigger points, and effect size of associations between PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and fractional exhaled nitric oxide (FeNO): A panel study with 16 follow-up visits over 4 years

Exposure to fine particulate matter (PM2.5) is a significant concern for respiratory health. However, the sources, trigger points, and effect size of specific associations between PM2.5 components, particularly polycyclic aromatic hydrocarbons (PAHs) and the airway inflammatory marker fractional exhaled nitric oxide (FeNO) have not been fully explored. In this study, 69 healthy college students were enrolled and followed up 16 times from 2014 to 2018. Individual FeNO was measured and ambient air PM2.5 samples were collected for 7 consecutive days before each follow-up. PAHs were quantified using Gas Chromatography-Mass Spectrometry. Linear mixed-effect regression models were employed to evaluate the associations between PM2.5-bound PAHs and FeNO. Additionally, PMF (Positive Matrix Factorization) was utilized to identify sources of PM2.5-bound PAHs and assess their impact on FeNO. Throughout the study, the average (SD) of ΣPAHs concentrations was 78.50 (128.9) ng/m3. PM2.5 and PM2.5-bound PAHs were significantly associated with FeNO at various lag days. Single-day lag analyses revealed maximum effects of PM2.5 on FeNO, with an increase of 7.71% (95% CI: 4.67%, 10.83%) per interquartile range (IQR) (48.10 μg/m3) increase of PM2.5 at lag2, and ΣPAHs showed a maximum elevation in FeNO of 6.40% (95% CI: 2.33%, 10.63%) at lag4 per IQR (57.39 ng/m3) increase. Individual PAHs exhibited diversity peak effects on FeNO at lag3 (6 of 17), lag4 (9 of 17) in the single-day model, and lag0-5 (8 of 17) (from lag0-1 to lag0-6) in the cumulative model. Source apportionment indicated coal combustion as the primary contributor (accounting for 30.7%). However, a maximum effect on FeNO (an increase of 21.57% (95% CI: 13.58%, 30.13%) per IQR increase) was observed with traffic emissions at lag4. The findings imply that strategic regulation of particular sources of PAHs, like traffic emissions, during specific periods could significantly contribute to safeguarding public health.

Inflammation as the nexus: exploring the link between acute myocardial infarction and chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), particularly following acute exacerbations (AE-COPD), significantly heightens the risks and mortality associated with acute myocardial infarction (AMI). The intersection of COPD and AMI is characterised by a considerable overlap in inflammatory mechanisms, which play a crucial role in the development of both conditions. Although extensive research has been conducted on individual inflammatory pathways in AMI and COPD, the understanding of thrombo-inflammatory crosstalk in comorbid settings remains limited. The effectiveness of various inflammatory components in reducing AMI infarct size or slowing COPD progression has shown promise, yet their efficacy in the context of comorbidity with COPD and AMI is not established. This review focuses on the critical importance of both local and systemic inflammation, highlighting it as a key pathophysiological connection between AMI and COPD/AE-COPD.

Circulating Levels of Hydrogen Sulfide (H2S) in Patients with Age-Related Diseases: A Systematic Review and Meta-Analysis

Hydrogen sulfide (H₂S) is an endogenous gasotransmitter that promotes multiple biological effects in many organs and tissues. An imbalanced biosynthesis of H₂S has been observed in animal models of age-related pathological conditions. However, the results from human studies are inconsistent. We performed a systematic review with meta-analysis of studies searched in Medline, Embase, Scopus, and CENTRAL databases. We included observational studies on patients with age-related diseases showing levels of H₂S in blood, plasma, or serum. All the analyses were carried out with R software. 31 studies were included in the systematic review and 21 in the meta-analysis. The circulating levels of H₂S were significantly reduced in patients with progressive, chronic, and degenerative diseases compared with healthy people (standardized mean difference, SMD: -1.25; 95% confidence interval, CI: -1.98; -0.52). When we stratified results by type of disorder, we observed a significant reduction in circulating levels of H₂S in patients with vascular disease (e.g., hypertension) (SMD: -1.32; 95% CI: -2.43; -0.22) or kidney disease (SMD: -2.24; 95% CI: -4.40; -0.08) compared with the control group. These results could support the potential use of compounds targeting the "H₂S system" to slow down the progression of many diseases in the elderly.

Comparative study of cigarette smoke, Klebsiella pneumoniae, and their combination on airway epithelial barrier function in mice

BACKGROUND

The airway epithelium acts as a physical barrier to protect pulmonary airways against pathogenic microorganisms and toxic substances, such as cigarette smoke (CS), bacteria, and viruses. The disruption of the structural integrity and dysfunction of the airway epithelium is related to the occurrence and progression of chronic obstructive pulmonary disease.

PURPOSE

The aim of this study is to compare the effects of CS, Klebsiella pneumoniae (KP), and their combination on airway epithelial barrier function.

METHODS

The mice were exposed to CS, KP, and their combination from 1 to 8 weeks. After the cessation of CS and KP at Week 8, we observed the recovery of epithelial barrier function in mice for an additional 16 weeks. To compare the epithelial barrier function among different groups over time, the mice were sacrificed at Weeks 4, 8, 16, and 24 and then the lungs were harvested to detect the pulmonary pathology, inflammatory cytokines, and tight junction proteins. To determine the underlying mechanisms, the BEAS-2B cells were treated with an epidermal growth factor receptor (EGFR) inhibitor (AG1478).

RESULTS

The results of this study suggested that the decreased lung function, increased bronchial wall thickness (BWT), elevated inflammatory factors, and reduced tight junction protein levels were observed at Week 8 in CS-induced mice and these changes persisted until Week 16. In the KP group, increased BWT and elevated inflammatory factors were observed only at Week 8, whereas in the CS + KP group, decreased lung function, lung tissue injury, inflammatory cell infiltration, and epithelial barrier impairment were observed at Week 4 and persisted until Week 24. To further determine the mechanisms of CS, bacteria, and their combination on epithelial barrier injury, we investigated the changes of EGFR and its downstream protein in the lung tissues of mice and BEAS-2B cells. Our research indicated that CS, KP, or their combination could activate EGFR, which can phosphorylate and activate ERK1/2, and this effect was more pronounced in the CS + KP group. Furthermore, the EGFR inhibitor AG1478 suppressed the phosphorylation of ERK1/2 and subsequently upregulated the expression of ZO-1 and occludin. In general, these results indicated that the combination of CS and KP caused more severe and enduring damage to epithelial barrier function than CS or KP alone, which might be associated with EGFR/ERK1/2 signaling.

CONCLUSION

Epithelial barrier injury occurred earlier, was more severe, and had a longer duration when induced by the combination of CS and KP compared with the exposure to CS or KP alone, which might be associated with EGFR/ERK signaling.

Up-regulation of PPAR-γ involved in the therapeutic effect of icariin on cigarette smoke-induced inflammation

Icariin (ICA) might be a potential anti-inflammatory medication in a variety of diseases including COPD, and previous studies showed that ICA could attenuate cigarette smoke (CS)-induced inflammation by inhibiting nuclear factor (NF)-κB. Peroxisome proliferator-activated receptor (PPAR) γ, a nuclear hormone receptor, has been reported to play a critical role in the inflammatory process in COPD. Whether PPAR-γ is involved in the anti-inflammatory effect of icariin on COPD has scarcely been explored. This study aimed at investigating the role of ICA in PPAR-γ expression in the CS-induced model, and then elucidating the therapeutic effects of ICA on COPD based on the PPARγ-NF-κB signaling pathway. The Beas-2B cells and H292 cells were induced with cigarette smoke extract (CSE) for 8 h after treatment with ICA for 16 h. The PPARγ expression and NF-κB pathway-related indicators were detected by western blotting, cellular immunofluorescence, and Real-time PCR. The PPARγ knock down or T0070907-treated Beas-2B cells were constructed to further investigate the relationship between the inhibition of NF-κB by ICA and PPARγ. A COPD model was established by CS exposure for 6 months, and ICA (40 mg/kg) was administrated by gastric perfusion. Then, the pulmonary function, lung histology, inflammatory cytokine levels, and protein expressions were detected. We found ICA up-regulated PPARγ protein expression in both Beas-2B cells and H292 cells, and it improved CSE-induced PPARγ down regulation and NF-κB activation. Furthermore, the inhibition of NF-κB pathway by ICA was partially dependent on PPARγ in the PPARγ knock down or T0070907-treated Beas-2B cells, suggesting that ICA attenuated CSE-induced inflammatory responses were associated with modulating the PPARγ-NF-κB pathway. Moreover, ICA showed similar effects on PPARγ and NF-κB expressions in the COPD model, and it effectively ameliorated the pulmonary function and lung inflammatory infiltration in the COPD rat model. Conclusively, the therapeutic effect of ICA on COPD was indirectly achieved by reducing airway inflammation, which was partially associated with modulating the PPARγ-NF-κB signaling pathway.

Assessment of Inter-relationship between Anemia and COPD In Accordance with Altitude

Background:

Anemia, a common blood disorder has been analysed for the risk for chronic obstructive pulmonary disease (COPD), a predominant respiratory condition. The COPD patients have been found to have anemia due to inflammation, accounting for about 7.5-33%.

Objectives:

To predict the influence of anemia in the COPD occurrence as well as to depict the role of change in altitudes in the occurrence of anemic as well as COPD.

Methodology:

A total of 17 hematological parameters has been analysed in the anemic and COPD patients along with the control samples of low and high altitude regions and the significance of the results has been calculated.

Results:

The hematological parameter comparison between anemia and COPD samples of two different altitudes showed highly significant variations (p<0.001) as well as slighter significant variations (p<0.01, p<0.05 and p<0.1) in most of the parameters as well as the prevalence of anemic condition among the COPD patients was significant.

Conclusion:

The considered hematological parameters shown to have a considerable influence in the occurrence of anemia and COPD as well as in the occurrence of anemia in COPD patients along with the change in altitudes.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.

Network pharmacology analysis uncovers the effect on apoptotic pathway by Bu-Fei formula for COPD treatment

ETHNOPHARMACOLOGICAL RELEVANCE

The Bu-Fei formula (BFF) has a positive effect on chronic obstructive pulmonary disease (COPD). However, its therapeutic mechanisms against COPD remain unknown.

AIM OF THE STUDY

To explore BFF's therapeutic effect on COPD and pharmacological mechanisms.

MATERIALS AND METHODS

First, the effect of BFF on rats with COPD was studied. Rats were randomly assigned to the blank, COPD, BFF treatment, and aminophylline (APL) treatment groups. From weeks 1-8, the COPD model was established by Klebsiella pneumoniae (KP) and cigarette smoke. Then, rats were given corresponding treatment for 8 weeks. The lung function of the rats was analyzed by whole-body plethysmography and pulmonary function testing, lung histopathology by electron microscopy and hematoxylin and eosin staining, and protein levels by immunohistochemistry. Next, the key components and targets of BFF in COPD were screened by network pharmacology analysis. Finally, the possible mechanism was verified through molecular docking and in vivo experiments.

RESULTS

BFF significantly improved lung function and lung histopathology in COPD rats and inhibit inflammation and collagen deposition in lung tissues. Also, 46 bioactive compounds and 136 BFF targets related to COPD were identified; among them, 3 compounds (quercetin, luteolin, and nobiletin) and 6 core targets (Akt1, BCL2, NF-κB p65, VEGFA, MMP9, and Caspase 8) were the key molecules associated with the mechanisms of BFF. The target enrichment analysis suggested that BFF's mechanisms might involve the apoptosis-related pathway; this possibility was supported by the molecular docking data. Lastly, BFF was indicated to increase the expression of core target genes and the production of apoptosis-related proteins.

CONCLUSIONS

BFF affects COPD by regulating the apoptosis-related pathways and targets.

Takotsubo syndrome and respiratory diseases: a systematic review

Takotsubo syndrome (TTS) is a rare cardiovascular condition characterized by reversible ventricular dysfunction and a presentation resembling that of acute myocardial infarction. An increasing number of studies has shown the association of respiratory diseases with TTS. Here, we comprehensively reviewed the literature and examined the available evidence for this association. After searching PubMed, EMBASE, and Cochrane Library databases, two investigators independently reviewed 3117 studies published through May 2021. Of these studies, 99 met the inclusion criteria (n = 108 patients). In patients with coexisting respiratory disease and TTS, the most common TTS symptom was dyspnoea (70.48%), followed by chest pain (24.76%) and syncope (2.86%). The most common type of TTS was apical, accounting for 81.13% of cases, followed by the midventricular (8.49%), basal (8.49%), and biventricular (1.89%) types. Among the TTS cases, 39.82% were associated with obstructive lung disease and 38.89% were associated with pneumonia. Coronavirus disease 2019 (COVID-19), which has been increasingly reported in patients with TTS, was identified in 29 of 42 (69.05%) patients with pneumonia. The overall mortality rate for patients admitted for respiratory disease complicated by TTS was 12.50%. Obstructive lung disease and pneumonia are the most frequently identified respiratory triggers of TTS. Medications and invasive procedures utilized in managing respiratory diseases may also contribute to the development of TTS. Furthermore, the diagnosis of TTS triggered by these conditions can be challenging due to its atypical presentation. Future prospective studies are needed to establish appropriate guidelines for managing respiratory disease with concurrent TTS.

Elastic fibers during aging and disease

Elastic fibers are essential constituents of the extracellular matrix of higher vertebrates and endow several tissues and organs including lungs, skin and blood vessels with elasticity and resilience. During the human lifespan, elastic fibers are exposed to a variety of enzymatic, chemical and biophysical influences, and accumulate damage due to their low turnover. Aging of elastin and elastic fibers involves enzymatic degradation, oxidative damage, glycation, calcification, aspartic acid racemization, binding of lipids and lipid peroxidation products, carbamylation and mechanical fatigue. These processes can trigger an impairment or loss of elastic fiber function and are associated with severe pathologies. There are different inherited or acquired pathological conditions, which influence the structure and function of elastic fibers and microfibrils predominantly in the cardiorespiratory system and skin. Inherited elastic-fiber pathologies have a direct or indirect impact on elastic-fiber formation due to mutations in the fibrillin genes (fibrillinopathies), in the elastin gene (elastinopathies) or in genes encoding proteins that are associated with microfibrils or elastic fibers. Acquired elastic-fiber pathologies appear age-related or as a result of multiple factors impairing tissue homeostasis. This review gives an overview on the fate of elastic fibers over the human lifespan in health and disease.

The role of air pollution (PM and NO2) in COVID-19 spread and lethality: A systematic review

A new coronavirus (SARS-CoV-2) has determined a pneumonia outbreak in China (Wuhan, Hubei Province) in December 2019, called COVID-19 disease. In addition to the person-to person transmission dynamic of the novel respiratory virus, it has been recently studied the role of environmental factors in accelerate SARS-CoV-2 spread and its lethality. The time being, air pollution has been identified as the largest environmental cause of disease and premature death in the world. It affects body's immunity, making people more vulnerable to pathogens. The hypothesis that air pollution, resulting from a combination of factors such as meteorological data, level of industrialization as well as regional topography, can acts both as a carrier of the infection and as a worsening factor of the health impact of COVID-19 disease, has been raised recently. With this review, we want to provide an update state of art relating the role of air pollution, in particular PM_2.5, PM₁₀ and NO₂, in COVID-19 spread and lethality. The Authors, who first investigated this association, often used different research methods or not all include confounding factors whenever possible. In addition, to date incidence data are underestimated in all countries and to a lesser extent also mortality data. For this reason, the cases included in the reviewed studies cannot be considered conclusive. Although it determines important limitations for direct comparison of results, and more studies are needed to strengthen scientific evidences and support firm conclusions, major findings are consistent, highlighting the important contribution of PM_2.5 and NO₂ as triggering of the COVID-19 spread and lethality, and with a less extent also PM₁₀, although the potential effect of airborne virus exposure it has not been still demonstrated.

Gallic acid ameliorates COPD-associated exacerbation in mice

COPD is an inflammatory lung disease, which is often exacerbated with microbial infections resulting in worsening of respiratory symptoms. Gallic acid (GA), a naturally occurring phenolic compound is known to possess anti-oxidant/anti-inflammatory activity. We have recently reported that GA protects against the elastase (ET) induced lung inflammation and emphysema and the present work was designed to investigate the beneficial effects of Gallic acid against ET + Lipopolysachharide (LPS) induced COPD exacerbation like condition in mice model. Our data showed that i.t. administration of LPS at 21 days after ET instillation resulted in significant infiltration of inflammatory cells particularly neutrophils (p < 0.0001) into the lungs along with elevated levels of pro-inflammatory cytokines like TNF-α, IL-1β and IL-6 (p < 0.0001). Interestingly, daily administration of GA (200 mg/Kg b. wt.) starting 7 days before ET instillation, significantly blunted the ET + LPS induced inflammation as indicated by reduced number of inflammatory cells particularly neutrophils (p < 0.0001) in BALF along with suppression of myeloperoxidase activity (p = 0.0009) and production of pro-inflammatory cytokines (p < 0.0001). Further, GA also restored the redox imbalance in the lungs towards normal. Additionally, phosphorylation of p65-NF-κB was found to be reduced (p = 0.015), which was associated with downregulation in the gene expression of IL-1β (p = 0.022) and TNF-α (p = 0.04). Conversely, GA treatment resulted in increased protein levels of Nrf2 (p = 0.021) with concomitant increase in transcription of its downstream target genes HO-1 (p = 0.033) and Prdx-1 (p = 0.006). Overall, our data show that GA effectively modulates COPD exacerbation manifestations in mice potentially by restoring redox imbalance in lungs.

Elastases and elastokines: elastin degradation and its significance in health and disease

Elastin is an important protein of the extracellular matrix of higher vertebrates, which confers elasticity and resilience to various tissues and organs including lungs, skin, large blood vessels and ligaments. Owing to its unique structure, extensive cross-linking and durability, it does not undergo significant turnover in healthy tissues and has a half-life of more than 70 years. Elastin is not only a structural protein, influencing the architecture and biomechanical properties of the extracellular matrix, but also plays a vital role in various physiological processes. Bioactive elastin peptides termed elastokines - in particular those of the GXXPG motif - occur as a result of proteolytic degradation of elastin and its non-cross-linked precursor tropoelastin and display several biological activities. For instance, they promote angiogenesis or stimulate cell adhesion, chemotaxis, proliferation, protease activation and apoptosis. Elastin-degrading enzymes such as matrix metalloproteinases, serine proteases and cysteine proteases slowly damage elastin over the lifetime of an organism. The destruction of elastin and the biological processes triggered by elastokines favor the development and progression of various pathological conditions including emphysema, chronic obstructive pulmonary disease, atherosclerosis, metabolic syndrome and cancer. This review gives an overview on types of human elastases and their action on human elastin, including the formation, structure and biological activities of elastokines and their role in common biological processes and severe pathological conditions.

Effects of High-Dose Vitamin D Replacement on the Serum Levels of Systemic Inflammatory Biomarkers in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is associated with increased inflammatory responses to noxious particles, which can be further enhanced during Acute Exacerbation of COPD (AECOPD). Considering the important immunoregulatory function of vitamin D, high prevalence of Vitamin D Deficiency (VDD) in COPD patients and a negative link between vitamin D levels and inflammatory biomarkers, suggests the seemingly interesting mechanism of vitamin D effects on inflammation resolution during the conventional treatment of AECOPD. The admitted AECOPD patients with VDD were recruited and randomly allocated to receive either 300,000 IU of intramuscular vitamin D (n = 35) or placebo (n = 35). Primary outcomes included inflammation resolution dynamics, which were assessed by monitoring the serum levels of IL-6, IL-8, and hs-CRP. Symptom recovery was evaluated based on the modified Medical Research Council (mMRC) dyspnea scale on the 1st and 6th days of admission. Secondary outcomes included the length of hospital stay (LOS) and 30-day mortality rates. Inflammatory biomarkers were highest at Day 1. Baseline vitamin D levels were 11.25 ± 3.09 and 10.59 ± 3.90 ng/ml (P = 0.45), which reached 11.35 ± 3.16 and 18.17 ± 4.24 by Day 6 (P < 0.001) in the placebo and, vitamin-D groups, respectively. IL-6 levels significantly decreased in the vitamin-D vs. placebo group on the 6^th day (P = 0.02); however, no significant differences were observed in IL-8 (P = 0.15) and hs-CRP (P = 0.24) levels, mMRC scale (P = 0.45), LOS (P = 0.20), and mortality rates (P = 0.61). Vitamin D replacement as adjunctive therapy may accelerate inflammation resolution in hospitalized AECOPD patients. Further studies were needed to establish vitamin D exact role on inflammation resolution in AECOPD.

Independent factors associate with hospital mortality in patients with acute exacerbation of chronic obstructive pulmonary disease requiring intensive care unit admission: Focusing on the eosinophil-to-neutrophil ratio

Background

Factors associated with hospital mortality are unclear in patients with acute exacerbation of COPD (AECOPD) requiring intensive care unit (ICU) admission. We aimed to characterize these patients and identify factors associated with hospital mortality.

Patients and methods

We used a retrospective observational case-control design and recruited patients between January 2015 and March 2017. Of 146 patients enrolled, 24 (16.4%) died during their hospital stay, while 122 survived.

Results

Multivariate logistic regression analyses revealed factors associated with hospital mortality: age (adjusted odds ratio [AOR] 1.12, 95% CI: 1.03–1.23), C-reactive protein (CRP) level >7.5 mg/dL at the emergency room (AOR 4.52, 95% CI: 1.27–16.04), peak eosinophil-to-neutrophil ratio (ENR)×10² on days 8–14 of treatment (AOR 0.22, 95% CI: 0.08–0.63), and in-hospital complications (AOR 4.23, 95% CI: 1.12–15.98) (all P<0.05). After receiver operating characteristic curve analyses, cutoff level for peak ENR×10² was 0.224. To examine the synergistic effects of CRP level and peak ENR, we divided patients into four groups: (G0, reference group) Peak ENR×10² >0.224 on days 8–14 and initial CRP <7.5 mg/dL; (G1) Peak ENR×10² >0.224 on days 8–14 and initial CRP >7.5 mg/dL; (G2) Peak ENR×10² <0.224 on days 8–14 and initial CRP <7.5 mg/dL; and (G3) Peak ENR×10² <0.224 on days 8–14 and initial CRP >7.5 mg/dL. For G2 and G3 patients, the AOR of mortality was significantly different from that of the reference group (G2: AOR 10.00, P = 0.020; G3: AOR 61.79, P<0.001). The relationship between 28-day mortality and the four groups was statistically significant (log-rank test, P<0.001).

Conclusion

Older age, initial CRP >7.5 mg/dL, peak ENR on days 8–14, and in-hospital complications were associated with hospital mortality in patients with AECOPD requiring ICU admission. Patients with both biomarkers, initial CRP >7.5 mg/dL, and peak ENR×10² <0.224 on days 8–14 of treatment, had an increased risk of hospital mortality.

Long-acting muscarinic antagonist versus long-acting β2 agonist/corticosteroid for moderate to severe chronic obstructive pulmonary disease patients: Exacerbation risk assessment

BACKGROUND

Whether the beneficial effects of long-acting muscarinic antagonists (LAMA) are better than those of long-acting β2 agonist/corticosteroids (LABA/ICS) in preventing exacerbations in chronic obstructive pulmonary disease (COPD) remains unclear. This study aimed to assess the risk of exacerbations in moderate to severe COPD patients receiving LAMA versus LABA/ICS.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with COPD (2008-2010). The inclusion criteria were age ≥ 40 years, forced expiratory volume in 1 second (FEV1) 30% to 80% of predicted value and at least three prescriptions for COPD medication, including LAMA or LABA/ICS.

RESULTS

Of the 557 COPD patients screened, 90 patients were enrolled in the analysis. The demographic characteristics of patients receiving LABA/ICS or LAMA were similar. The all exacerbation rates was significantly higher in patients with global initiative for chronic obstructive lung disease stage II COPD treated with LABA/ICS than in those treated with LAMA (p = 0.001), regardless of previous exacerbation history. Patients with previous exacerbation history showed an independent increase in the risk of moderate or severe exacerbation compared with those without exacerbation history (hazard ratio 3.86, 95% CI 1.75-8.53, p = 0.001).

CONCLUSION

In comparison with LABA/ICS, LAMA is beneficial in reducing exacerbation risk for moderate COPD. Previous exacerbation history independently predicts the future risk of exacerbation regardless of treatment.

Associations between inhaled doses of PM2.5-bound polycyclic aromatic hydrocarbons and fractional exhaled nitric oxide

Exposure to fine particulate matter (PM_2.5) is linked to various respiratory outcomes. However, the associations of concentrations of PM_2.5-bound polycyclic aromatic hydrocarbons (PM_2.5-bound PAHs) with airway inflammatory indices remains unclear. To assess effects of short-term exposure to PM_2.5-bound PAHs on fractional exhaled nitric oxide (FeNO), we conducted a pilot study with repeated measures. We recruited 20 postgraduate students in Wuhan city, China, and repeatedly measured outdoor and indoor (including dormitories, offices and laboratories) PM_2.5-bound PAHs concentrations, urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) and FeNO levels in the four seasons. Subsequently, we estimated inhaled doses of PM_2.5-bound PAHs based on the micro-environmental PM_2.5-bound PAHs concentrations, time-activity patterns and referred inhalation rates. We assessed the association of inhaled doses of PM_2.5-bound PAHs with FeNO using linear mixed-effects regression models. We found the positive associations of urinary ∑OH-PAHs levels with inhaled doses of indoor PM_2.5-bound PAHs (including dormitories and offices) (all p < 0.05). A one-unit increase in inhaled doses of PM_2.5-bound PAHs or in urinary concentrations of ∑OH-PAHs was corresponded to a maximum FeNO increase of 13.5% (95% CI: 5.4, 22.2) at lag2 day or of 6.8% (95% CI: 3.4, 10.2) at lag1 day. Inhaled doses of PM_2.5-bound PAHs or urinary OH-PAHs was positively related to increased FeNO, they may be accepted as a short-term biomarker of exposure to PAHs in air. Exposure to PM_2.5-bound PAHs in indoor air may contribute more to the body burden of PAHs than outdoor air, and exhibited stronger effect on increased FeNO rather than urinary OH-PAHs.