Persistent airway inflammation and emphysema progression on CT scan in ex-smokers observed for 4 years

TLR7 promotes smoke-induced experimental lung damage through the activity of mast cell tryptase

Toll-like receptor 7 (TLR7) is known for eliciting immunity against single-stranded RNA viruses, and is increased in both human and cigarette smoke (CS)-induced, experimental chronic obstructive pulmonary disease (COPD). Here we show that the severity of CS-induced emphysema and COPD is reduced in TLR7-deficient mice, while inhalation of imiquimod, a TLR7-agonist, induces emphysema without CS exposure. This imiquimod-induced emphysema is reduced in mice deficient in mast cell protease-6, or when wild-type mice are treated with the mast cell stabilizer, cromolyn. Furthermore, therapeutic treatment with anti-TLR7 monoclonal antibody suppresses CS-induced emphysema, experimental COPD and accumulation of pulmonary mast cells in mice. Lastly, TLR7 mRNA is increased in pre-existing datasets from patients with COPD, while TLR7+ mast cells are increased in COPD lungs and associated with severity of COPD. Our results thus support roles for TLR7 in mediating emphysema and COPD through mast cell activity, and may implicate TLR7 as a potential therapeutic target.

Role of necroptosis in airflow limitation in chronic obstructive pulmonary disease: focus on small-airway disease and emphysema

Airflow limitation with intractable progressive mechanisms is the main disease feature of chronic obstructive pulmonary disease (COPD). The pathological process of airflow limitation in COPD involves necroptosis, a form of programmed necrotic cell death with pro-inflammatory properties. In this paper, the correlations of small-airway disease and emphysema with airflow limitation in COPD were firstly reviewed; then, based on this, the effects of necroptosis on small-airway disease and emphysema were analysed, and the possible mechanisms of necroptosis causing airflow limitation in COPD were explored. The results showed that airflow limitation is caused by a combination of small-airway disease and emphysema. In addition, toxic particulate matter stimulates epithelial cells to trigger necroptosis, and necroptosis promotes the expulsion of cell contents, the abnormal hyperplasia of pro-inflammatory mediators and the insufficient clearance of dead cells by macrophages; these processes, coupled with the interaction of necroptosis and oxidative stress, collectively result in small-airway disease and emphysema in COPD.

Insights gained in the pathology of lung disease through single cell transcriptomics

The human lung is a relatively quiescent organ in the normal healthy state but contains stem/progenitor cells that contribute to normal tissue maintenance and either repair or remodeling in response to injury and disease. Maintenance or repair lead to proper restoration of functional lung tissue and maintenance of physiological functions, with remodeling resulting in altered structure and function that is typically associated with disease. Knowledge of cell types contributing to lung tissue maintenance and repair/remodeling have largely relied on mouse models of injury-repair and lineage tracing of local progenitors. Therefore, many of the functional alterations underlying remodeling in human lung disease, have remained poorly defined. However, the advent of advanced genomics approaches to define the molecular phenotype of lung cells at single cell resolution has paved the way for rapid advances in our understanding of cell types present within the normal human lung and changes that accompany disease. Here we summarize recent advances in our understanding of disease-related changes in the molecular phenotype of human lung epithelium that have emerged from single-cell transcriptomic studies. We focus attention on emerging concepts of epithelial transitional states that characterize the pathological remodeling that accompanies chronic lung diseases, including idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, cystic fibrosis, and asthma. Concepts arising from these studies are actively evolving and require corroborative studies to improve our understanding of disease mechanisms. Whenever possible we highlight opportunities for providing a unified nomenclature in this rapidly advancing field of research. This article is protected by copyright. All rights reserved.

Lung tissue shows divergent gene expression between chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are characterized by shared exposures and clinical features, but distinct genetic and pathologic features exist. These features have not been well-studied using large-scale gene expression datasets. We hypothesized that there are divergent gene, pathway, and cellular signatures between COPD and IPF.

METHODS

We performed RNA-sequencing on lung tissues from individuals with IPF (n = 231) and COPD (n = 377) compared to control (n = 267), defined as individuals with normal spirometry. We grouped the overlapping differential expression gene sets based on direction of expression and examined the resultant sets for genes of interest, pathway enrichment, and cell composition. Using gene set variation analysis, we validated the overlap group gene sets in independent COPD and IPF data sets.

RESULTS

We found 5010 genes differentially expressed between COPD and control, and 11,454 genes differentially expressed between IPF and control (1% false discovery rate). 3846 genes overlapped between IPF and COPD. Several pathways were enriched for genes upregulated in COPD and downregulated in IPF; however, no pathways were enriched for genes downregulated in COPD and upregulated in IPF. There were many myeloid cell genes with increased expression in COPD but decreased in IPF. We found that the genes upregulated in COPD but downregulated in IPF were associated with lower lung function in the independent validation cohorts.

CONCLUSIONS

We identified a divergent gene expression signature between COPD and IPF, with increased expression in COPD and decreased in IPF. This signature is associated with worse lung function in both COPD and IPF.

Risk factors for pneumothorax and pulmonary hemorrhage following computed tomography-guided transthoracic core-needle biopsy of subpleural lung lesions

BACKGROUND

Identifying the risk factors for complications may alert the physicians and help them adjust their plans before performing computed tomography-guided lung biopsies. Reportedly, a pleura-nodule distance longer than 2.0 cm is a strong predictor for pneumothorax and pulmonary hemorrhage. However, the rate and risk factors of biopsy-associated complications in subpleural lesions have not been assessed. This study aimed to identify the risk factors for pneumothorax and pulmonary hemorrhage in subpleural lesions ≤2.0 cm in depth.

METHODS

Altogether, 196 patients (196 subpleural lesions, lesion depth: 0.1-2.0 cm) who underwent computed tomography-guided transthoracic core-needle biopsies between March 2017 and November 2017 were retrospectively analyzed. Univariate analysis of risk factors including patient-related, lesion-related, and procedure-related characteristics was performed for pneumothorax ≥1 cm and pulmonary hemorrhage ≥2 cm after the biopsy. Multivariate logistic regression analysis was performed to identify the independent risk factors.

RESULTS

Pneumothorax ≥1 cm and pulmonary hemorrhage ≥2 cm were identified in 35 (17.9%) and 32 (16.3%) cases, respectively. In the multivariate analysis, a longer needle path (odds ratio [OR], 1.976; 95% confidence interval [CI], 1.113-3.506; p = 0.020) and low attenuation along the biopsy tract (OR, 3.080; 95% CI, 1.038-9.139; p = 0.043) were predictors of pneumothorax ≥ 1 cm. Ground-glass lesions (OR, 2.360; 95% CI, 1.009-5.521; p = 0.048) and smaller needle-pleura angle (OR, 0.325; 95% CI, 0.145-0.728; p = 0.006) were associated with pulmonary hemorrhage ≥2 cm.

CONCLUSION

For subpleural lesions ≤2.0 cm in depth, a puncture route having a shorter needle path and passing through the lung parenchyma with higher attenuation may reduce the risk of biopsy-associated pneumothorax ≥1 cm. A higher needle-pleura angle may reduce the risk of pulmonary hemorrhage ≥2 cm in the short axis.

Association between smoking cessation and obstructive spirometry pattern among Korean adults aged 40-79 years

Smoking cessation aids in restoring lung function. However, whether long-term cessation can fully restore lung function has not been studied thoroughly, especially in Asian countries. This study aimed to evaluate the association between smoking cessation status and obstructive spirometry pattern among Koreans aged 40-79 years. In total, 6298 men and 8088 women aged 40-79 years from the Korea National Health and Nutrition Examination Survey (2015-2019) were analyzed for smoking cessation status, including the duration after quitting. Current-smokers showed a higher likelihood of having an obstructive spirometry pattern than never-smokers among both men (odds ratio [OR]: 3.15, 95% confidence interval [CI]: 2.32-4.29) and women (OR: 2.60, 95% CI: 1.59-4.23). In men, the effect tended to decrease with longer duration after cessation, but male ex-smokers who had quit smoking ≥ 20 years ago still showed a higher likelihood of having an obstructive spirometry pattern than male never-smokers (OR: 1.40, 95% CI: 1.05-1.89). In female ex-smokers, there was no significant association with the obstructive spirometry pattern, compared to that in female never-smokers. This study emphasizes the benefits of smoking cessation, possibility of long-lasting harm to lung function due to tobacco smoking, and importance of smoking prevention.

Alpha-1 antitrypsin deficiency and recombinant protein sources with focus on plant sources: Updates, challenges and perspectives

Alpha-1 antitrypsin deficiency (A1ATD) is an autosomal recessive disease characterized by low plasma levels of A1AT, a serine protease inhibitor representing the most abundant circulating antiprotease normally present at plasma levels of 1-2 g/L. The dominant clinical manifestations include predispositions to early onset emphysema due to protease/antiprotease imbalance in distal lung parenchyma and liver disease largely due to unsecreted polymerized accumulations of misfolded mutant A1AT within the endoplasmic reticulum of hepatocytes. Since 1987, the only FDA licensed specific therapy for the emphysema component has been infusions of A1AT purified from pooled human plasma at the 2020 cost of up to US $200,000/year with the risk of intermittent shortages. In the past three decades various, potentially less expensive, recombinant forms of human A1AT have reached early stages of development, one of which is just reaching the stage of human clinical trials. The focus of this review is to update strategies for the treatment of the pulmonary component of A1ATD with some focus on perspectives for therapeutic production and regulatory approval of a recombinant product from plants. We review other competitive technologies for treating the lung disease manifestations of A1ATD, highlight strategies for the generation of data potentially helpful for securing FDA Investigational New Drug (IND) approval and present challenges in the selection of clinical trial strategies required for FDA licensing of a New Drug Approval (NDA) for this disease.

Spontaneous Breathing Through Increased Airway Resistance Augments Elastase-Induced Pulmonary Emphysema

Introduction

Resistive breathing (RB), the pathophysiologic hallmark of chronic obstructive pulmonary disease (COPD), especially during exacerbations, is associated with significant inflammation and mechanical stress on the lung. Mechanical forces are implicated in the progression of emphysema that is a major pathologic feature of COPD. We hypothesized that resistive breathing exacerbates emphysema.

Methods

C57BL/6 mice were exposed to 0.75 units of pancreatic porcine elastase intratracheally to develop emphysema. Resistive breathing was applied by suturing a nylon band around the trachea to reduce surface area to half for the last 24 or 72 hours of a 21-day time period after elastase treatment in total. Following RB (24 or 72 hours), lung mechanics were measured and bronchoalveolar lavage (BAL) was performed. Emphysema was quantified by the mean linear intercept (Lm) and the destructive index (DI) in lung tissue sections.

Results

Following 21 days of intratracheal elastase exposure, Lm and DI increased in lung tissue sections [Lm (μm), control 39.09±0.76, elastase 62.05±2.19, p=0.003 and DI, ctr 30.95±2.75, elastase 73.12±1.75, p<0.001]. RB for 72 hours further increased Lm by 64% and DI by 19%, compared to elastase alone (p<0.001 and p=0.02, respectively). RB induced BAL neutrophilia in elastase-treated mice. Static compliance (C_st) increased in elastase-treated mice [C_st (mL/cmH2O), control 0.067±0.001, elastase 0.109±0.006, p<0.001], but superimposed RB decreased C_st, compared to elastase alone [C_st (mL/cmH2O), elastase+RB24h 0.090±0.004, p=0.006 to elastase, elastase+RB72h 0.090±0.005, p=0.006 to elastase].

Conclusion

Resistive breathing augments pulmonary inflammation and emphysema in an elastase-induced emphysema mouse model.

Regenerative Metaplastic Clones in COPD Lung Drive Inflammation and Fibrosis

Chronic obstructive pulmonary disease (COPD) is a progressive condition of chronic bronchitis, small airway obstruction, and emphysema that represents a leading cause of death worldwide. While inflammation, fibrosis, mucus hypersecretion, and metaplastic epithelial lesions are hallmarks of this disease, their origins and dependent relationships remain unclear. Here we apply single-cell cloning technologies to lung tissue of patients with and without COPD. Unlike control lungs, which were dominated by normal distal airway progenitor cells, COPD lungs were inundated by three variant progenitors epigenetically committed to distinct metaplastic lesions. When transplanted to immunodeficient mice, these variant clones induced pathology akin to the mucous and squamous metaplasia, neutrophilic inflammation, and fibrosis seen in COPD. Remarkably, similar variants pre-exist as minor constituents of control and fetal lung and conceivably act in normal processes of immune surveillance. However, these same variants likely catalyze the pathologic and progressive features of COPD when expanded to high numbers.

Serum levels of L1-ORF1p and airflow limitation

LINE-1 (long interspersed nuclear element-1) is a group of polymorphic DNA sequences in the human genome that mobilise via RNA binding proteins, reverse transcriptase and endonuclease to alter the host genome via mutational insertions, chromosomal rearrangements and reprogramming of gene expression (reviewed by Ramoset al. [1]). Full-length LINE-1 sequences encode two proteins: L1-ORF1p, a 40-kDa protein with nucleic acid binding activity; and L1-ORF2p, a 150-kDa protein with endonuclease and reverse transcriptase activities. The activity of LINE-1 is repressed in somatic tissues via DNA methylation and covalent protein modifications, and reactivated by displacement of retinoblastoma-associated proteins from the regulatory region [2]. Recent studies in our laboratory have implicated LINE-1 as a master regulator of human bronchial epithelial cell phenotypes in experimental in vitro and in vivo models [3].

In a population-based study, higher circulating levels of L1-ORF1p were associated with lower lung function levels and increased risk for airflow limitation among former smokershttp://bit.ly/2ZEIjNv

Modulation of the endogenous Annexin A1 in a cigarette smoke cessation model: Potential therapeutic target in reversing the damage caused by smoking?

BACKGROUND

Smoking cessation may help in the reversal of inflammation and damage caused by smoking. The endogenous annexin A1 (AnxA1) protein has anti-inflammatory effects which instigates the understanding of its role in the attenuation of inflammatory processes caused by smoking.

MATERIAL AND METHODS

Wistar rats were exposed to cigarette smoke for 8 weeks. After the exposure period, one of the groups remained other 8 weeks in the absence of smoke. Animals not exposed to smoke were used as control. Blood, trachea and lungs were obtained for histopathological, immunohistochemical and biochemical analyses.

RESULTS

Loss of cilia of the tracheal lining epithelium was found by smoke exposure, but smoking cessation led to recovery of the tracheal epithelium. Similarly, chronically exposed-to-smoke animals showed increased lymphocytes and macrophages in bronchoalveolar lavage and higher levels of glucose and gamma-GT in their blood. Reduction of lymphocytes, glucose and gamma-GT occurred after smoking cessation. In addition, IL-1β, IL-6, IL-10, TNF-α and MCP-1 levels were elevated by smoke exposure. Smoking cessation significantly reduced the levels of IL-1β, IL-6 and MCP-1 but increased the IL-10 concentration. Numerous mast cells and macrophages were observed in the lung of chronically exposed-to-smoke animals with reduction by smoking cigarette abstinence. AnxA1 increased expression and concomitant NF-κB reduction were found in the smoking cessation group.

CONCLUSION

Our results showed that cigarette abstinence promoted partial recovery of the inflammatory process. The attenuation of the inflammatory profile may be associated with the overexpression of AnxA1 protein.

Geroprotectors as a therapeutic strategy for COPD - where are we now?

Although current therapies in chronic obstructive pulmonary disease (COPD) improve the quality of life, they do not satisfactorily reduce disease progression or mortality. There are still many gaps in knowledge about the cellular, molecular, and genetic mechanisms contributing to pathobiology of this disease. However, increasing evidence suggests that accelerated aging, chronic systemic inflammation, and oxidative stress play major roles in pathogenesis in COPD, thus opening new opportunities in therapy. Therefore, the aim of our review was to describe and discuss some of the most widely used therapeutics that affect the root cause of aging and oxidative stress (metformin, melatonin, sirolimus, statins, vitamin D, and testosterone) in context of COPD therapy.

Peripheral Tc17 and Tc17/Interferon-γ Cells are Increased and Associated with Lung Function in Patients with Chronic Obstructive Pulmonary Disease

Background:

Chronic obstructive pulmonary disease (COPD) is characterized by progressive loss of lung function and local and systemic inflammation, in which CD8⁺ T-cells are believed to play a key role. Activated CD8⁺ T-cells differentiate into distinct subpopulations, including interferon-γ (IFN-γ)-producing Tc1 and interleukin (IL)-17-producing Tc17 cells. Recent evidence indicates that Tc17 cells exhibit considerable plasticity and may convert into IL-17/IFN-γ-double producing (Tc17/IFN-γ) cells when driven by inflammatory conditions. The aim of this study was to investigate the Tc17/IFN-γ subpopulation in peripheral blood of patients with COPD and to evaluate their potential roles in this disease.

Methods:

Peripheral blood samples were collected from 15 never-smokers, 23 smokers with normal lung function, and 25 patients with COPD (Global Initiative for Chronic Obstructive Lung Disease 2–4). Proportions of the IL-17/IFN-γ-double expressing subpopulation were assessed using flow cytometry. Plasma concentrations of cytokines favoring Tc17/IFN-γ differentiation were measured by enzyme-linked immunosorbent assay.

Results:

Patients with COPD had higher proportions of Tc17 cells and Tc17/IFN-γ cells in the peripheral blood than smokers and never-smokers. The plasticity of Tc17 cells was higher than that of Th17 cells. The percentages of Tc17 cells and Tc17/IFN-γ cells showed negative correlations with forced expiratory volume in 1 s % predicted value (r = −0.418, P = 0.03; r = −0.596, P = 0.002, respectively). The plasma concentrations of IL-6, transforming growth factor-β1, and IL-12 were significantly higher in patients with COPD compared with smokers and never-smokers.

Conclusions:

Peripheral Tc17 cells are increased and more likely to convert to Tc17/IFN-γ cells in COPD, suggesting that Tc17 cell plasticity may be involved in persistent inflammation of the disease.

Cigarette Smoke and DNA Cleavage Promote Lung Inflammation and Emphysema

Smoking-related lung diseases are among the most preventable and incurable ailments in the world. Smokers are at increased risk of developing chronic obstructive pulmonary disease that can be further complicated by emphysema and lung cancer. A subset of former smokers shows persistent lung inflammation and progressive loss of lung function, indicating a role for activation of acquired immunity in smoking-induced lung diseases. In addition to the well-established noxious effects of volatile compounds in cigarette smoke, incomplete combustion of tobacco generates nano-sized carbon black (nCB) that accumulate in lung myeloid dendritic cells and macrophages. Experimentally, intra-nasal instillation nCB can cause airway inflammation and emphysema in mice, underscoring their pathogenic role in inflammatory lung diseases. High throughput analyses of macrophages that have engulfed nCB reveal de novo activation of DNA repair enzymes, and histological studies provide evidence for DNA double-stranded breaks. Emphysematous lung myeloid dendritic cells that contain nCB express pro-inflammatory cytokines, and can efficiently differentiate naive CD4 T cells to interferon-g-secreting T helper 1 and interleukin 17A expressing cell subsets. Together these findings indicate that nCB accumulation in lung innate immune cells can initiate and sustain lung inflammation and promote emphysema development.

Serum Levels of Surfactant Proteins in Patients with Combined Pulmonary Fibrosis and Emphysema (CPFE)

Introduction

Emphysema and idiopathic pulmonary fibrosis (IPF) present either per se or coexist in combined pulmonary fibrosis and emphysema (CPFE). Serum surfactant proteins (SPs) A, B, C and D levels may reflect lung damage. We evaluated serum SP levels in healthy controls, emphysema, IPF, and CPFE patients and their associations to disease severity and survival.

Methods

122 consecutive patients (31 emphysema, 62 IPF, and 29 CPFE) and 25 healthy controls underwent PFTs, ABG-measurements, 6MWT and chest HRCT. Serum levels of SPs were measured. Patients were followed-up for 1-year.

Results

SP-A and SP-D levels differed between groups (p = 0.006 and p<0.001 respectively). In post-hoc analysis, SP-A levels differed only between controls and CPFE (p<0.05) and CPFE and emphysema (p<0.05). SP-D differed between controls and IPF or CPFE (p<0.001 for both comparisons). In IPF SP-B correlated to pulmonary function while SP-A, correlated to the Composite Physiological Index (CPI). Controls current smokers had higher SP-A and SP-D levels compared to non-smokers (p = 0.026 and p = 0.023 respectively). SP-D levels were higher in CPFE patients with extended emphysema (p = 0.042). In patients with IPF, SP-B levels at the upper quartile of its range (≥26 ng/mL) presented a weak association with reduced survival (p = 0.05).

Conclusion

In conclusion, serum SP-A and SP-D levels were higher where fibrosis exists or coexists and related to disease severity, suggesting that serum SPs relate to alveolar damage in fibrotic lungs and may reflect either local overproduction or overleakage. The weak association between high levels of SP-B and survival needs further validation in clinical trials.

Present and future utility of computed tomography scanning in the assessment and management of COPD

Computed tomography (CT) is the modality of choice for imaging the thorax and lung structure. In chronic obstructive pulmonary disease (COPD), it used to recognise the key morphological features of emphysema, bronchial wall thickening and gas trapping. Despite this, its place in the investigation and management of COPD is yet to be determined, and it is not routinely recommended. However, lung CT already has important clinical applications where it can be used to diagnose concomitant pathology and determine which patients with severe emphysema are appropriate for lung volume reduction procedures. Furthermore, novel quantitative analysis techniques permit objective measurements of pulmonary and extrapulmonary manifestations of the disease. These techniques can give important insights into COPD, and help explore the heterogeneity and underlying mechanisms of the condition. In time, it is hoped that these techniques can be used in clinical trials to help develop disease-specific therapy and, ultimately, as a clinical tool in identifying patients who would benefit most from new and existing treatments. This review discusses the current clinical applications for CT imaging in COPD and quantification techniques, and its potential future role in stratifying disease for optimal outcome.

A Randomized, Placebo-controlled Trial of Roflumilast. Effect on Proline-Glycine-Proline and Neutrophilic Inflammation in Chronic Obstructive Pulmonary Disease

RATIONALE

Roflumilast is a therapeutic agent in the treatment of chronic obstructive pulmonary disease (COPD). It has antiinflammatory effects; however, it is not known whether it can affect a biologic pathway implicated in COPD pathogenesis and progression. The self-propagating acetyl-proline-glycine-proline (AcPGP) pathway is a novel means of neutrophilic inflammation that is pathologic in the development of COPD. AcPGP is produced by extracellular matrix collagen breakdown with prolyl endopeptidase and leukotriene A4 hydrolase serving as the enzymes responsible for its production and degradation, respectively.

OBJECTIVES

We hypothesized that roflumilast would decrease AcPGP, halting the feed-forward cycle of inflammation.

METHODS

We conducted a single-center, placebo-controlled, randomized study investigating 12 weeks of roflumilast treatment added to current therapy in moderate-to-severe COPD with chronic bronchitis. Subjects underwent sputum and blood analyses, pulmonary function testing, exercise tolerance, and quality-of-life assessment at 0, 4, and 12 weeks.

MEASUREMENTS AND MAIN RESULTS

Twenty-seven patients were enrolled in the intention-to-treat analysis. Roflumilast treatment decreased sputum AcPGP by more than 50% (P < 0.01) and prolyl endopeptidase by 46% (P = 0.02), without significant improvement in leukotriene A4 hydrolase activity compared with placebo. Roflumilast also reduces other inflammatory markers. There were no significant changes in lung function, quality of life, or exercise tolerance between roflumilast- and placebo-treated groups.

CONCLUSIONS

Roflumilast reduces pulmonary inflammation through decreasing prolyl endopeptidase activity and AcPGP. As expected for lower AcPGP levels, markers of neutrophilic inflammation are blunted. Inhibiting this self-propagating pathway lessens the overall inflammatory burden, which may alter the natural history of COPD, including the risk of exacerbation. Clinical trial registered with www.clinicaltrials.gov (NCT 01572948).

Characteristics of prevalent and new COPD cases in Greece: the GOLDEN study

Background

Greece has one of the highest rates of smoking and chronic obstructive pulmonary disease (COPD) in Europe.

Aim

The study aimed to record both the disease characteristics among a sample of Greek COPD patients and the nationwide rates of newly diagnosed COPD cases.

Methods

In this noninterventional, epidemiological cross-sectional study, a representative nationwide sample of 45 respiratory centers provided data on the following: 1) the demographic and clinical characteristics of COPD patients and 2) newly diagnosed COPD cases monitored over a period of 6 months by each physician.

Results

Data from 6,125 COPD patients were collected. Advanced age (median age: 68 years), male predominance (71.3%), largely overweight status with median body mass index (BMI) =27.5 kg/m², high percentage of current and ex-smokers (89.8%), and presence of comorbidities (81.9%) were evident in the sample. According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2011 criteria, majority of the COPD patients had moderate or severe airflow limitation (61%). Severity of airflow limitation was significantly associated with older age, male sex, obesity, ex-smoking status, and presence of comorbidity (all P-values <0.001). A total of 61.3% of the patients received medication, mostly bronchodilators (64.4%) and fixed-dose combinations of long-acting β₂-agonists and inhaled corticosteroids (39.9%), while 35.9% reported taking medication on demand. The majority (81.1%) of patients reported a preference for fewer inhalations of their bronchodilator therapy. Based on the mixed-effect Poisson model, the rate of newly diagnosed COPD cases was estimated to be 18.2% (95% confidence interval: 14.9–22.3) per pulmonologist/3 months. Of those newly diagnosed, the majority of patients had mild or moderate airflow limitation (78.2%).

Conclusion

The Greek Obstructive Lung Disease Epidemiology and health ecoNomics study reflected the real-life profile of COPD patients and provided evidence on the profile of new COPD cases in Greece. Various demographic factors were delineated, which can assist in designing more effective diagnostic and management strategies for COPD in Greece.

Does lysozyme play a role in the pathogenesis of COPD?

Elastic fiber injury is an important process in the pathogenesis of chronic obstructive pulmonary disease (COPD), particularly with regard to the development of pulmonary emphysema. Damage to these fibers results in uneven distribution of mechanical forces in the lung, leading to dilatation and rupture of alveolar walls. While the role of various enzymes and oxidants in this process has been well-documented, we propose that a previously unsuspected agent, lysozyme, may contribute significantly to the changes in elastic fibers observed in this disease. Studies from our laboratory have previously shown that lysozyme preferentially binds to elastic fibers in human emphysematous lungs. On the basis of this finding, it is hypothesized that the attachment of lysozyme to these fibers enhances their susceptibility to injury, and further impairs the transfer of mechanical forces in the lung, leading to increased alveolar wall damage and enhanced progression of COPD. The hypothesized effects of lysozyme are predicated on its interaction with hyaluronan (HA), a long-chain polysaccharide that is found in close proximity to elastic fibers. By preventing the binding of HA to elastic fibers in COPD, lysozyme may interfere with the protective effect of this polysaccharide against enzymes and oxidants that degrade these fibers. Furthermore, the loss of the hydrating effect of HA on these fibers may impair their elastic properties, greatly increasing the probability of their fragmentation in response to mechanical forces. The proposed hypothesis may explain why the content of HA is significantly lower in the lungs of COPD patients. It may also contribute to the design of clinical trials involving the use of exogenously administered HA as a potential treatment for COPD.

Distribution of T-cell subsets in BAL fluid of patients with mild to moderate COPD depends on current smoking status and not airway obstruction

BACKGROUND

COPD is characterized by chronic inflammation. CD8+ T cells and CD4+ T cells have both been implicated in the inflammatory response. We investigated whether the lymphocyte and T-cell subpopulations in BAL differ between patients with COPD who are current smokers and those who are ex-smokers.

METHODS

Forty never smokers, 40 smokers with normal lung function, and 38 patients with COPD, GOLD (Global Initiative for Chronic Obstructive Pulmonary Disease) stage I-II (27 smokers and 11 ex-smokers) underwent BAL. Using flow cytometry, cells were analyzed from BAL and blood for T-cell subsets, B cells, natural killer cells, and natural killer T (NKT)-like cells. The differentiation status of CD4+ T cells was also determined.

RESULTS

Smokers with or without COPD had higher percentages of CD8+ T cells and NKT-like cells in BAL than did never smokers and ex-smokers with COPD. Most of the NKT-like cells were CD8+. In contrast, the percentages of CD4+ T cells were lower in the smoking than in the nonsmoking groups. In blood, the frequency of CD4+ T cells was increased in the two smoking groups. Current smokers also had increased numbers of activated (CD69+) naive and effector CD4+ T cells in BAL compared with nonsmokers, particularly in patients with COPD. In male smokers with COPD, the percentage of CD8+ T cells in BAL positively correlated with the number of cigarettes per day.

CONCLUSIONS

Current smoking status has a greater impact than airway obstruction on the distribution of T-cell subsets in BAL of patients with mild to moderate COPD. This fact must be considered when the role of T cells in COPD is evaluated. Our results stress the importance of subgrouping patients with COPD in terms of smoking.

Molecular processes that drive cigarette smoke-induced epithelial cell fate of the lung

Cigarette smoke contains numerous chemical compounds, including abundant reactive oxygen/nitrogen species and aldehydes, and many other carcinogens. Long-term cigarette smoking significantly increases the risk of various lung diseases, including chronic obstructive pulmonary disease and lung cancer, and contributes to premature death. Many in vitro and in vivo studies have elucidated mechanisms involved in cigarette smoke-induced inflammation, DNA damage, and autophagy, and the subsequent cell fates, including cell death, cellular senescence, and transformation. In this Translational Review, we summarize the known pathways underlying these processes in airway epithelial cells to help reveal future challenges and describe possible directions of research that could lead to better management and treatment of these diseases.

Impact of inflammation, emphysema, and smoking cessation on V/Q in mouse models of lung obstruction

Background

Chronic obstructive pulmonary disease (COPD) is known to greatly affect ventilation (V) and perfusion (Q) of the lung through pathologies such as inflammation and emphysema. However, there is little direct evidence regarding how these pathologies contribute to the V/Q mismatch observed in COPD and models thereof. Also, little is known regarding how smoking cessation affects V/Q relationships after inflammation and airspace enlargement have become established. To this end, we have quantified V/Q on a per-voxel basis using single photon emission computed tomography (SPECT) in mouse models of COPD and lung obstruction.

Methods

Three distinct murine models were used to investigate the impact of different pathologies on V/Q, as measured by SPECT. Lipopolysaccharide (LPS) was used to produce neutrophilic inflammation, porcine pancreatic elastase (PPE) was used to produce emphysema, and long-term cigarette smoke (CS) exposure and cessation were used to investigate the combination of these pathologies.

Results

CS exposure resulted in an increase in mononuclear cells and neutrophils, an increase in airspace enlargement, and an increase in V/Q mismatching. The inflammation produced by LPS was more robust and predominantly neutrophilic, compared to that of cigarette smoke; nevertheless, inflammation alone caused V/Q mismatching similar to that seen with long-term CS exposure. The emphysematous lesions caused by PPE administration were also capable of causing V/Q mismatch in the absence of inflammation. Following CS cessation, inflammatory cell levels returned to those of controls and, similarly, V/Q measures returned to normal despite evidence of persistent mild airspace enlargement.

Conclusions

Both robust inflammation and extensive airspace enlargement, on their own, were capable of producing V/Q mismatch. As CS cessation resulted in a return of V/Q mismatching and inflammatory cell counts to control levels, lung inflammation is likely a major contributor to V/Q mismatch observed in the cigarette smoke exposure model as well as in COPD patients. This return of V/Q mismatching to control values also took place in the presence of mild airspace enlargement, indicating that emphysematous lesions must be of a larger volume before affecting the lung significantly. Early smoking cessation is therefore critical before emphysema has an irreversible impact on gas exchange.

Sputum myeloperoxidase in chronic obstructive pulmonary disease

Background

Airway inflammation, especially neutrophilic airway inflammation, is a cardinal pathophysiologic feature in chronic obstructive pulmonary disease (COPD) patients. The ideal biomarkers characterizing the inflammation might have important potential clinical applications in disease assessment and therapeutic intervention. Sputum myeloperoxidase (MPO) is recognized as a marker of neutrophil activity. The purpose of this meta-analysis is to determine whether sputum MPO levels could reflect disease status or be regulated by regular medications for COPD.

Methods

Studies were identified by searching PubMed, Embase, the Cochrane Database, CINAHL and http://www.controlled-trials.com for relevant reports published before September 2012. Observational studies comparing sputum MPO in COPD patients and healthy subjects or asthmatics, or within the COPD group, and studies comparing sputum MPO before and after treatment were all included. Data were independently extracted by two investigators and analyzed using STATA 10.0 software.

Results

A total of 24 studies were included in the meta-analysis. Sputum MPO levels were increased in stable COPD patients when compared with normal controls, and this increase was especially pronounced during exacerbations as compared with MPO levels during the stable state. Theophylline treatment was able to reduce MPO levels in COPD patients, while glucocorticoid treatment failed to achieve the same result.

Conclusion

Sputum MPO might be a promising biomarker for guiding COPD management; however, further investigations are needed to confirm this.

Effects of N-acetylcysteine in ozone-induced chronic obstructive pulmonary disease model

Introduction

Chronic exposure to high levels of ozone induces emphysema and chronic inflammation in mice. We determined the recovery from ozone-induced injury and whether an antioxidant, N-acetylcysteine (NAC), could prevent or reverse the lung damage.

Methods

Mice were exposed to ozone (2.5 ppm, 3 hours/12 exposures, over 6 weeks) and studied 24 hours (24h) or 6 weeks (6W) later. Nac (100 mg/kg, intraperitoneally) was administered either before each exposure (preventive) or after completion of exposure (therapeutic) for 6 weeks.

Results

After ozone exposure, there was an increase in functional residual capacity, total lung volume, and lung compliance, and a reduction in the ratio of forced expiratory volume at 25 and 50 milliseconds to forced vital capacity (FEV₂₅/FVC, FEV₅₀/FVC). Mean linear intercept (L_m) and airway hyperresponsiveness (AHR) to acetylcholine increased, and remained unchanged at 6W after cessation of exposure. Preventive NAC reduced the number of BAL macrophages and airway smooth muscle (ASM) mass. Therapeutic NAC reversed AHR, and reduced ASM mass and apoptotic cells.

Conclusion

Emphysema and lung function changes were irreversible up to 6W after cessation of ozone exposure, and were not reversed by NAC. The beneficial effects of therapeutic NAC may be restricted to the ASM.

Thioredoxin-1 protects against neutrophilic inflammation and emphysema progression in a mouse model of chronic obstructive pulmonary disease exacerbation

Background

Exacerbations of chronic obstructive pulmonary disease (COPD) are characterized by acute enhancement of airway neutrophilic inflammation under oxidative stress and can be involved in emphysema progression. However, pharmacotherapy against the neutrophilic inflammation and emphysema progression associated with exacerbation has not been established. Thioredoxin-1 has anti-oxidative and anti-inflammatory properties and it can ameliorate neutrophilic inflammation through anti-chemotactic effects and prevent cigarette smoke (CS)-induced emphysema. We aimed to determine whether thioredoxin-1 can suppress neutrophilic inflammation and emphysema progression in a mouse model of COPD exacerbation and if so, to reveal the underlying mechanisms.

Results

Mice were exposed to CS and then challenged with polyinosine-polycytidylic acid [poly(I:C)], an agonist for virus-induced innate immunity. Airway neutrophilic inflammation, oxidative stress and lung apoptosis were enhanced in smoke-sensitive C57Bl/6, but not in smoke-resistant NZW mice. Exposure to CS and poly(I:C) challenge accelerated emphysema progression in C57Bl/6 mice. Thioredoxin-1 suppressed neutrophilic inflammation and emphysema progression. Poly(I:C) caused early neutrophilic inflammation through keratinocyte-derived chemokine and granulocyte-macrophage colony-stimulating factor (GM-CSF) release in the lung exposed to CS. Late neutrophilic inflammation was caused by persistent GM-CSF release, which thioredoxin-1 ameliorated. Thioredoxin-1 enhanced pulmonary mRNA expression of MAP kinase phosphatase 1 (MKP-1), and the suppressive effects of thioredoxin-1 on prolonged GM-CSF release and late neutrophilic inflammation disappeared by inhibiting MKP-1.

Conclusion

Using a mouse model of COPD exacerbation, we demonstrated that thioredoxin-1 ameliorated neutrophilic inflammation by suppressing GM-CSF release, which prevented emphysema progression. Our findings deepen understanding of the mechanisms underlying the regulation of neutrophilic inflammation by thioredoxin-1 and indicate that thioredoxin-1 could have potential as a drug to counteract COPD exacerbation.

Computed tomography-based centrilobular emphysema subtypes relate with pulmonary function

Introduction:

Centrilobular emphysema (CLE) is recognized as low attenuation areas (LAA) with centrilobular pattern on high-resolution computed tomography (CT). However, several shapes of LAA are observed. Our preliminary study showed three types of LAA in CLE by CT-pathologic correlations. This study was performed to investigate whether the morphological features of LAA affect pulmonary functions.

Materials and Methods:

A total of 73 Japanese patients with stable CLE (63 males, 10 females) were evaluated visually by CT and classified into three subtypes based on the morphology of LAA including shape and sharpness of border; patients with CLE who shows round or oval LAA with well-defined border (Subtype A), polygonal or irregular-shaped LAA with ill-defined border (Subtype B), and irregular-shaped LAA with ill-defined border coalesced with each other (Subtype C). CT score, pulmonary function test and smoking index were compared among three subtypes.

Results:

Twenty (27%), 45 (62%) and 8 cases (11%) of the patients were grouped into Subtype A, Subtype B and Subtype C, respectively. In CT score and smoking index, both Subtype B and Subtype C were significantly higher than Subtype A. In FEV₁%, Subtype C was significantly lower than both Subtype A and Subtype B. In diffusing capacity of lung for carbon monoxide, Subtype B was significantly lower than Subtype A.

Conclusion:

The morphological differences of LAA may relate with an airflow limitation and alveolar diffusing capacity. To assess morphological features of LAA may be helpful for the expectation of respiratory function.

Cigarette smoke-induced collagen destruction; key to chronic neutrophilic airway inflammation?

Background

Cigarette smoking induces inflammatory responses in all smokers and is the major risk factor for lung disease such as chronic obstructive pulmonary disease (COPD). In this progressive disease, chronic inflammation in the lung contributes to lung tissue destruction leading to the formation of chemotactic collagen fragments such as N-acetylated Proline-Glycine-Proline (N-ac-PGP). The generation of this tripeptide is mediated by a multistep pathway involving matrix metalloproteases (MMPs) 8 and 9 and prolyl endopeptidase (PE). Here we investigated whether cigarette smoke extract (CSE) stimulates human PMNs to breakdown whole matrix collagen leading to the generation of the chemotactic collagen fragment N-ac-PGP.

Methodology/Principal Findings

Incubating PMNs with CSE led to the release of chemo-attractant CXCL8 and proteases MMP8 and MMP9. PMNs constitutively expressed PE activity as well as PE protein. Incubating CSE-primed PMNs with collagen resulted in collagen breakdown and in N-ac-PGP generation. Incubation of PMNs with the tripeptide N-ac-PGP resulted in the release of CXCL8, MMP8 and MMP9. Moreover, we tested whether PMNs from COPD patients are different from PMNs from healthy donors. Here we show that the intracellular basal PE activity of PMNs from COPD patients increased 25-fold compared to PMNs from healthy donors. Immunohistological staining of human lung tissue for PE showed that besides neutrophils, macrophages and epithelial cells express PE.

Conclusions

This study indicates that neutrophils activated by cigarette smoke extract can breakdown collagen into N-ac-PGP and that this collagen fragment itself can activate neutrophils, which may lead in vivo to a self-propagating cycle of neutrophil infiltration, chronic inflammation and lung emphysema. MMP-, PE- or PGP-inhibitors can serve as an attractive therapeutic target and may open new avenues towards effective treatment of COPD.

RTP801 is required for ceramide-induced cell-specific death in the murine lung

Key host responses to the stress induced by environmental exposure to cigarette smoke (CS) are responsible for initiating pathogenic effects that may culminate in emphysema development. CS increases lung ceramides, sphingolipids involved in oxidative stress, structural alveolar cell apoptosis, and inhibition of apoptotic cell clearance by alveolar macrophages, leading to the development of emphysema-like pathology. RTP801, a hypoxia and oxidative stress sensor, is also increased by CS, and has been recently implicated in both apoptosis and inflammation. We investigated whether inductions of ceramide and RTP801 are mechanistically linked, and evaluated their relative importance in lung cell apoptosis and airspace enlargement in vivo. As reported, direct lung instillation of either RTP801 expression plasmid or ceramides in mice triggered alveolar cell apoptosis and oxidative stress. RTP801 overexpression up-regulated lung ceramide levels 2.6-fold. In turn, instillation of lung ceramides doubled the lung content of RTP801. Cell sorting after lung tissue dissociation into single-cell suspension showed that ceramide triggers both endothelial and epithelial cell apoptosis in vivo. Interestingly, mice lacking rtp801 were protected against ceramide-induced apoptosis of epithelial type II cells, but not type I or endothelial cells. Furthermore, rtp801-null mice were protected from ceramide-induced alveolar enlargement, and exhibited improved static lung compliance compared with wild-type mice. In conclusion, ceramide and RTP801 participate in alveolar cell apoptosis through a process of mutual up-regulation, which may result in self-amplification loops, leading to alveolar damage.

Longitudinal study of spatially heterogeneous emphysema progression in current smokers with chronic obstructive pulmonary disease

BACKGROUND

Cigarette smoke is the main risk factor for emphysema, which is a key pathology in chronic obstructive pulmonary disease (COPD). Low attenuation areas (LAA) in computed tomography (CT) images reflect emphysema, and the cumulative size distribution of LAA clusters follows a power law characterized by the exponent D. This property of LAA clusters can be explained by model simulation, where mechanical force breaks alveolar walls causing local heterogeneous lung tissue destruction. However, a longitudinal CT study has not investigated whether continuous smoking causes the spatially heterogeneous progression of emphysema.

METHODS

We measured annual changes in ratios of LAA (LAA%), D and numbers of LAA clusters (LAN) in CT images acquired at intervals of ≥ 3 years from 22 current and 31 former smokers with COPD to assess emphysema progression. We constructed model simulations using CT images to morphologically interpret changes in current smokers.

RESULTS

D was decreased in current and former smokers, whereas LAA% and LAN were increased only in current smokers. The annual changes in LAA%, D, and LAN were greater in current, than in former smokers (1.03 vs. 0.37%, p=0.008; -0.045 vs. -0.01, p=0.004; 13.9 vs. 1.1, p=0.007, respectively). When LAA% increased in model simulations, the coalescence of neighboring LAA clusters decreased D, but the combination of changes in D and LAN in current smokers could not be explained by the homogeneous emphysema progression model despite cluster coalescence. Conversely, a model in which LAAs heterogeneously increased and LAA clusters merged somewhat in relatively advanced emphysematous regions could reflect actual changes.

CONCLUSIONS

Susceptibility to parenchymal destruction induced by continuous smoking is not uniform over the lung, but might be higher in local regions of relatively advanced emphysema. These could result in the spatially heterogeneous progression of emphysema in current smokers.

Histone deacetylase activity is decreased in peripheral blood monocytes in patients with COPD

Background

Histone deacetylase (HDAC) is an enzyme that regulates chromatin structure and inflammatory gene expression. In patients with chronic obstructive pulmonary disease (COPD), while accumulating evidence indicates that the activity of HDAC is decreased in lung tissue alveolar macrophages, HDAC activity in peripheral inflammatory cells has not yet been evaluated in detail.

Methods

HDAC activities in peripheral blood mononuclear cells (PBMC) were investigated in patients with stable COPD (n = 26), non-smoking controls (n = 13), and smoking controls (n = 10), respectively. HDAC activity was measured using an HDAC Activity/Inhibitor Screening Assay Kit. Serum interleukine-8 (CXCL8) levels were determined by ELISA techniques. Lung function test was carried out according to the ATS/ERS guidelines.

Results

Compared with healthy non-smokers, HDAC activity in the PBMCs of COPD patients was decreased by 40% (13.06 ± 5.95 vs. 21.39 ± 4.92 (μM/μg), p < 0.001). In patients with COPD, HDAC activity was negatively correlated to smoke intensity (r = -0.867, p < 0.001). In COPD patients who had smoked for more than 40 pack-years, HDAC activity in PBMC was 40% lower than that in COPD patients who had smoked fewer than 40 pack-years.

Moreover, serum CXCL8 levels in patients with COPD were significantly higher than that in controls and were negatively correlated to HDAC activities.

Conclusion

In patients with COPD, HDAC activity in the PBMCs is lower than that in healthy controls. The reduction of HDAC activity may be associated with smoking exposure through inflammatory pathways.

In Vivo Computed Tomography as a Research Tool to Investigate Asthma and COPD: Where Do We Stand?

Computed tomography (CT) is a clinical tool widely used to assess and followup asthma and chonic obstructive pulmonary disease (COPD) in humans. Strong efforts have been made the last decade to improve this technique as a quantitative research tool. Using semiautomatic softwares, quantification of airway wall thickness, lumen area, and bronchial wall density are available from large to intermediate conductive airways. Skeletonization of the bronchial tree can be built to assess its three-dimensional geometry. Lung parenchyma density can be analysed as a surrogate of small airway disease and emphysema. Since resident cells involve airway wall and lung parenchyma abnormalities, CT provides an accurate and reliable research tool to assess their role in vivo. This litterature review highlights the most recent advances made to assess asthma and COPD with CT, and also their drawbacks and the place of CT in clarifying the complex physiopathology of both diseases.