The pathogenesis of chronic obstructive pulmonary disease (COPD) is characterized by an interaction of environmental influences, particularly cigarette smoking, and genetic determinants. Given the global increase in COPD, research on the genomic variants that affect susceptibility to this complex disorder is reviving. In the present study, we investigated whether single nucleotide polymorphisms in 'a disinter-grin and metalloprotease' 33 (ADAM33) are associated with the development and course of COPD.
Patients and design
We genotyped 150 German COPD patients and 152 healthy controls for the presence of the F+1 and S_2 SNPs in ADAM 33 that lead to the base pair exchange G to A and C to G, respectively. To assess whether these genetic variants are influential in the course of COPD, we subdivided the cohort into two subgroups comprising 60 patients with a stable and 90 patients with an unstable course of disease.
In ADAM33, the frequency of the F+1 A allele was 35.0% among stable and 43.9% among unstable COPD subjects, which was not significantly different from the 35.5% found in the controls (P = 0.92 and P = 0.07, respectively). The frequency of the S_2 mutant allele in subjects with a stable COPD was 23.3% (P = 0.32), in subjects with an unstable course 30.6% (P = 0.47).
The study shows that there is no significant difference in the distribution of the tested SNPs between subjects with and without COPD. Furthermore, these polymorphisms appear to have no consequences for the stability of the disease course.
COPD; ADAM33; genetics
Chronic obstructive pulmonary disease (COPD) is associated with airway inflammation. Although smoking cessation improves symptoms and the decline in lung function in COPD, it is unknown whether bronchial inflammation in patients with established COPD varies with the duration of smoking cessation.
114 patients (99 men) with COPD of mean (SD) age 62 (8) years, a median (IQR) smoking history of 42 (31–55) pack years, no inhaled or oral corticosteroids, all current or ex‐smokers (n = 42, quit >1 month, median cessation duration 3.5 years), post‐bronchodilator FEV1 63 (9)% predicted, and FEV1/IVC 48 (9)% were studied cross sectionally. The numbers of subepithelial T lymphocytes (CD3, CD4, CD8), neutrophils, macrophages, eosinophils, mast cells, and plasma cells were measured in bronchial biopsy specimens (median (IQR)/0.1 mm2) using fully automated image analysis.
Ex‐smokers with COPD had higher CD3+, CD4+, and plasma cell numbers than current smokers with COPD (149 (88–225) v 108 (61–164), p = 0.036; 58 (32–90) v 40 (25–66), p = 0.023; and 9.0 (5.5–20) v 7.5 (3.1–14), p = 0.044, respectively), but no difference in other inflammatory cells. Short term ex‐smokers (<3.5 years) had higher CD4+ and CD8+ cell numbers than current smokers (p = 0.017, p = 0.023; respectively). Conversely, long term ex‐smokers (quit ⩾3.5 years) had lower CD8+ cell numbers than short term ex‐smokers (p = 0.009), lower CD8/CD3 ratios than both current smokers and short‐term ex‐smokers (p = 0.012, p = 0.003; respectively), and higher plasma cell numbers than current smokers (p = 0.003).
With longer duration of smoking cessation, CD8 cell numbers decrease and plasma cell numbers increase. This indicates that bronchial T lymphocyte and plasma cell counts, but not other inflammatory cells, are related to duration of smoking cessation in patients with COPD.
plasma cells; T lymphocytes; chronic obstructive pulmonary disease; smoking cessation
ADAMs (a disintegrin and metalloprotease) constitute a family of cell surface proteins containing disintegrin and metalloprotease domains which associate features of adhesion molecules and proteases. ADAMTSs (a disintegrin and metalloprotease with thrombospondin motifs) bear thrombospondin type I motifs in C-terminal extremity, and most of them are secreted proteins. Because genetic studies have shown that ADAM-33 gene polymorphisms are associated with asthma, we designed this study to assess mRNA expression profile of several ADAM and ADAMTS proteases in sputum from patients with asthma and to investigate the relationship between expression of these proteases and asthma-associated inflammation and airway obstruction. mRNA expression profile of selected ADAM and ADAMTS proteinases (ADAM-8, -9, -10, -12, -15, -17, and -33; ADAMTS-1, -2, -15, -16, -17, -18, and -19), their physiological inhibitors TIMP-1 and TIMP-3, and RECK, a membrane-anchored MMP activity regulator, was obtained by RT-PCR analysis performed on cells collected by sputum induction from 21 patients with mild to moderate asthma and 17 healthy individuals. mRNA levels of ADAM-8, ADAM-9, ADAM-12, TIMP-1, and TIMP-3 were significantly increased, whereas mRNA levels coding for ADAMTS-1, ADAMTS-15, and RECK were significantly decreased in patients with asthma compared with control patients. ADAM-8 expression was negatively correlated with the forced expiratory volume at the first second (FEV1) (r = −0.57, P < 0.01), whereas ADAMTS-1 and RECK expressions were positively correlated to FEV1 (r = 0.45, P < 0.05, and r = 0.55, P = 0.01, respectively). We conclude that expression of ADAMs and ADAMTSs and their inhibitors is modulated in airways from patients with asthma and that these molecules may play a role in the pathogenesis of asthma.
Eosinophilic airway inflammation has successfully been used to tailor anti-inflammatory therapy in chronic obstructive pulmonary disease (COPD). Airway hyperresponsiveness (AHR) by indirect challenges is associated with airway inflammation. We hypothesized that AHR to inhaled mannitol captures eosinophilia in induced sputum in COPD.
Twenty-eight patients (age 58 ± 7.8 yr, packyears 40 ± 15.5, post-bronchodilator FEV1 77 ± 14.0%predicted, no inhaled steroids ≥4 wks) with mild-moderate COPD (GOLD I-II) completed two randomized visits with hypertonic saline-induced sputum and mannitol challenge (including sputum collection). AHR to mannitol was expressed as response-dose-ratio (RDR) and related to cell counts, ECP, MPO and IL-8 levels in sputum.
There was a positive correlation between RDR to mannitol and eosinophil numbers (r = 0.47, p = 0.03) and level of IL-8 (r = 0.46, p = 0.04) in hypertonic saline-induced sputum. Furthermore, significant correlations were found between RDR and eosinophil numbers (r = 0.71, p = 0.001), level of ECP (r = 0.72, p = 0.001), IL-8 (r = 0.57, p = 0.015) and MPO (r = 0.64, p = 0.007) in sputum collected after mannitol challenge. ROC-curves showed 60% sensitivity and 100% specificity of RDR for >2.5% eosinophils in mannitol-induced sputum.
In mild-moderate COPD mannitol hyperresponsiveness is associated with biomarkers of airway inflammation. The high specificity of mannitol challenge suggests that the test is particularly suitable to exclude eosinophilic airways inflammation, which may facilitate individualized treatment in COPD.
Netherlands Trial Register (NTR): NTR1283
Chronic obstructive pulmonary disease (COPD) is influenced by both environmental and genetic factors. ADAM33 (a disintegrin and metalloproteinase 33) has been one of the most exciting candidate genes for asthma since its first association with the disease in Caucasian populations. Recently, ADAM33 was shown to be associated with excessive decline of lung function and COPD. The aim of this study was to evaluate the potential relationship between polymorphisms of ADAM33 and COPD in a Han population in northeastern China.
A total of 312 COPD patients and a control group of 319 healthy volunteers were recruited for this study. Eight polymorphic loci (V4, T+1, T2, T1, S2, S1, Q-1, and F+1) of ADAM33 were selected for genotyping. Genotypes were determined by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.
Statistically significant differences in the distributions of the T2G, T1G, S2C, and Q-1G alleles between patients and controls were observed (P < 0.001, odds ratio (OR) = 2.81, 95% confidence interval (CI) = 2.19-3.61; P < 0.001, OR = 2.60, 95% CI = 2.06-3.30; P = 0.03, OR = 1.31, 95% CI = 1.02-1.69; and P < 0.001, OR = 1.93, 95% CI = 1.50-2.50, respectively). Haplotype analysis showed that the frequencies of the CGGGGAGC, CGGGGAGT, CGGGCAGC, and CGGGGGGC haplotypes were significantly higher in the case group than in the control group (P = 0.0002, 0.0001, 0.0005, and 0.0074, respectively). In contrast, the haplotype CGAAGAGC was more common in the control group than in the case group (P < 0.0001).
These preliminary results suggest an association between ADAM33 polymorphisms and COPD in a Chinese Han population.
Chronic obstructive pulmonary disease is a common condition and a major cause of mortality. COPD is characterized by irreversible airflow obstruction. The physiological abnormalities observed in COPD are due to a combination of emphysema and obliteration of the small airways in association with airway inflammation. The predominant cells involved in this inflammatory response are CD8+ lymphocytes, neutrophils, and macrophages. Although eosinophilic airway inflammation is usually considered a feature of asthma, it has been demonstrated in large and small airway tissue samples and in 20%–40% of induced sputum samples from patients with stable COPD. This airway eosinophilia is increased in exacerbations. Thus, modifying eosinophilic inflammation may be a potential therapeutic target in COPD. Eosinophilic airway inflammation is resistant to inhaled corticosteroid therapy, but does respond to systemic corticosteroid therapy, and the degree of response is related to the intensity of the eosinophilic inflammation. In COPD, targeting treatment to normalize the sputum eosinophilia reduced the number of hospital admissions. Whether controlling eosinophilic inflammation in COPD patients with an airway eosinophilia will modify disease progression and possibly alter mortality is unknown, but warrants further investigation.
COPD; sputum eosinophilia; corticosteroids
Smoking effects on physiological and gross pathology in chronic obstructive pulmonary disease (COPD) are relatively well described. However, there is little known in COPD about the detailed interrelationships between lung function and inflammatory profiles in different airway compartments from the same individual and whether airway inflammation in these different compartments differs in ex- and current smokers with established COPD.
We compared sputum, bronchoalveolar (BAL), and airway wall inflammatory profiles in current versus ex-smokers and related this to smoking intensity and lung function in 17 current and 17 ex-smokers with mild to moderate COPD.
Current smokers had more sputum mast cells (% differential and absolute numbers), whereas ex-smokers had increased sputum neutrophils. In BAL, there was a significant increase in eosinophils in current smokers, but ex-smokers had significantly increased neutrophils, lymphocytes, and epithelial cells. There were no cell profile differences observed in airway biopsies between current and ex-smokers and there were no correlations between the individual inflammatory cell populations in any of the airway compartments. In current smokers only, smoking intensity was negatively correlated with lung function, and associated with a reduction in overall cellularity of both sputum and BAL.
Airway inflammation persists in ex-smokers with COPD, but differs from COPD current smokers. The impact of smoking appears to vary in different airway compartments and any direct relationships between cellularity and lung function tended to be negative, ie, worse lung function indicated the presence of fewer cells.
current smokers; ex-smokers; airway cellularity; sputum; BAL; endobronchial biopsies
The ADAM33 gene is associated with the pathophysiology of Chronic Obstructive Pulmonary Disease (COPD) and atherosclerosis. In this study we investigated all-cause, COPD and cardiovascular mortality, in relation to single nucleotide polymorphisms (SNPs) in ADAM33 (Q_1, S_1, S_2, T_1 and T_2) that were genotyped in 1,390 subjects from the Vlagtwedde/Vlaardingen cohort. Participants were examined at entry in 1989/1990 and followed up till evaluation of the vital status on December 31st, 2008. Using Cox proportional hazards regression we estimated the risk of the SNPs in relation to mortality, adjusting for gender, age, FEV1, height, place of residence and packyears of smoking. Additionally, we performed stratified analyses according to gender and smoking habits. After 18 years, 284 (20.4%) subjects had died (107 due to cardiovascular disease and 20 due to COPD). Individuals homozygous for the minor allele of SNP T_2 had an increased risk of all-cause and cardiovascular mortality compared to wild types: hazard ratio 3.6 (95% confidence interval 2.0 to 6.7) and 3.4 (1.2 to 9.5) respectively. Individuals homozygous for the minor allele of S_1, S_2, T_2 or Q_1 had a significantly increased risk of COPD mortality. In stratified analyses the risk of all-cause mortality associated with SNP T_2 did not change: females 3.5 (1.5 to 8.3), males 3.1 (1.2 to 7.6), never smokers 3.8 (0.9 to 16.3), ever smokers 3.6 (1.8 to 7.2). This study shows for the first time that ADAM33 is a pleiotropic gene that is associated with all-cause, COPD and cardiovascular mortality, independent of potential confounders.
Patients with chronic obstructive pulmonary disease (COPD) exhibit dominant features of chronic bronchitis, emphysema, and/or asthma, with a common phenotype of airflow obstruction. COPD pulmonary physiology reflects the sum of pathological changes in COPD, which can occur in large central airways, small peripheral airways, and the lung parenchyma. Quantitative or high-resolution computed tomography is used as a surrogate measure for assessment of disease progression. Different biological or molecular markers have been reported that reflect the mechanistic or pathogenic triad of inflammation, proteases, and oxidants and correspond to the different aspects of COPD histopathology. Similar to the pathogenic triad markers, genetic variations or polymorphisms have also been linked to COPD-associated inflammation, protease–antiprotease imbalance, and oxidative stress. Furthermore, in recent years, there have been reports identifying aging-associated mechanistic markers as downstream consequences of the pathogenic triad in the lungs from COPD patients. For this review, the authors have limited their discussion to a review of mechanistic markers and genetic variations and their association with COPD histopathology and disease status.
senescence; apoptosis; chronic obstructive pulmonary disease; bronchitis; emphysema
Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms.
The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13).
In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter.
This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD.
Squamous metaplasia (SM) is common in smokers and is associated with airway obstruction in chronic obstructive pulmonary disease (COPD). A major mechanism of airway obstruction in COPD is thickening of the small airway walls. We asked whether SM actively contributes to airway wall thickening through alteration of epithelial-mesenchymal interactions in COPD. Using immunohistochemical staining, airway morphometry, and fibroblast culture of lung samples from COPD patients; genome-wide analysis of an in vitro model of SM; and in vitro modeling of human airway epithelial-mesenchymal interactions, we provide evidence that SM, through the increased secretion of IL-1β, induces a fibrotic response in adjacent airway fibroblasts. We identify a pivotal role for integrin-mediated TGF-β activation in amplifying SM and driving IL-1β–dependent profibrotic mesenchymal responses. Finally, we show that SM correlates with increased severity of COPD and that fibroblast expression of the integrin αvβ8, which is the major mediator of airway fibroblast TGF-β activation, correlated with disease severity and small airway wall thickening in COPD. Our findings have identified TGF-β as a potential therapeutic target for COPD.
Inflammation is a core feature of acute chronic obstructive pulmonary disease (COPD) exacerbations. It is important to focus on inflammation since it gives insight into the pathological changes causing an exacerbation, thereby possibly providing directions for future therapies which modify inflammation.
To provide a cell-by-cell overview of the inflammatory processes during COPD exacerbations. To evaluate cell activation, and cytokine production, cellular interactions, damaging effects of inflammatory mediators to tissue, and the relation to symptoms at the onset of COPD exacerbations. To speculate on future therapeutic options to modify inflammation during COPD exacerbations.
During COPD exacerbations, there is increased airway wall inflammation, with pathophysiological influx of eosinophils, neutrophils, and lymphocytes. Although links have been suggested between the increase in eosinophils and lymphocytes and a viral etiology of the exacerbation, and between the increase in neutrophils and a bacterial aetiology, these increases in both inflammatory cell types are not limited to the respective aetiologies and the underlying mechanisms remain elusive.
Further research is required to fully understand the inflammatory mechanisms in the onset and development of COPD exacerbations. This might make inflammatory pathway-specific intervention possible, resulting in a more effective treatment of COPD exacerbations with fewer side effects.
COPD; exacerbation; inflammation; therapy
Rationale: Inflammation is now recognized as an integral part of the pathogenesis of chronic obstructive pulmonary disease (COPD). In contrast to the sterile airways of normal lungs, bacterial pathogens are often isolated from the airways in stable COPD. This “colonization” of the tracheobronchial tree, currently believed to be innocuous, could serve as an inflammatory stimulus, independent of current tobacco smoke exposure.
Objective: To test the hypothesis that bacterial colonization is associated with airway inflammation in stable COPD.
Methods: Bronchoscopy with bronchoalveolar lavage (BAL) was performed in three groups of subjects: 26 ex-smokers with stable COPD (COPD), 20 ex-smokers without COPD (ex-smokers), and 15 healthy nonsmokers (nonsmokers). Quantitative bacterial cultures, cell counts, chemokine, cytokine, proteinase/antiproteinase, and endotoxin levels in the BAL fluid were compared.
Results: Potentially pathogenic bacteria were recovered at ⩾ 100 cfu/ml in 34.6% of COPD, 0% of ex-smokers, and in 6.7% of nonsmokers (p = 0.003). All values are expressed as median (interquartile range). Subjects with colonized COPD had significantly greater relative (12.0 [28.4] vs. 3.0 [7.8]%, p = 0.03) and absolute (4.98 [5.26] × 104/ml vs. 3.04 [2.82] × 104/ml, p = 0.02) neutrophil counts, interleukin 8 (33.8 [189.8] vs. 16.9 [20.1] pg/ml, p = 0.005), active matrix metalloproteinase-9 (2.16 [4.30] vs. 0.84 [0.99] U/ml, p = 0.03), and endotoxin (36.0 [72.6] vs. 3.55 [7.17] mEU/ml, p = 0.004) levels in the BAL than the subjects with noncolonized COPD. These inflammatory constituents of BAL were also significantly elevated in subjects with colonized COPD when compared with ex-smokers and nonsmokers.
Conclusions: Bacterial colonization is associated with neutrophilic airway lumen inflammation in ex-smokers with COPD and could contribute to progression of airway disease in COPD.
bacterial colonization; chronic obstructive pulmonary disease; neutrophilic inflammation
Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation and/or airflow limitation due to pulmonary emphysema. Chronic bronchitis, pulmonary emphysema, and bronchial asthma may all be associated with airflow limitation; therefore, exacerbation of asthma may be associated with the pathophysiology of COPD. Furthermore, recent studies have suggested that the exacerbation of asthma, namely virus-induced asthma, may be associated with a wide variety of respiratory viruses. COPD and asthma have different underlying pathophysiological processes and thus require individual therapies. Exacerbation of both COPD and asthma, which are basically defined and diagnosed by clinical symptoms, is associated with a rapid decline in lung function and increased mortality. Similar pathogens, including human rhinovirus, respiratory syncytial virus, influenza virus, parainfluenza virus, and coronavirus, are also frequently detected during exacerbation of asthma and/or COPD. Immune response to respiratory viral infections, which may be related to the severity of exacerbation in each disease, varies in patients with both COPD and asthma. In this regard, it is crucial to recognize and understand both the similarities and differences of clinical features in patients with COPD and/or asthma associated with respiratory viral infections, especially in the exacerbative stage. In relation to definition, epidemiology, and pathophysiology, this review aims to summarize current knowledge concerning exacerbation of both COPD and asthma by focusing on the clinical significance of associated respiratory virus infections.
asthma; COPD; respiratory virus; exacerbation; overlap syndrome; human rhinovirus; respiratory syncytial virus
Chronic obstructive pulmonary disease (COPD) is a major global health problem and is predicted to become the third most common cause of death by 2020. Apart from the important preventive steps of smoking cessation, there are no other specific treatments for COPD that are as effective in reversing the condition, and therefore there is a need to understand the pathophysiological mechanisms that could lead to new therapeutic strategies. The development of experimental models will help to dissect these mechanisms at the cellular and molecular level. COPD is a disease characterized by progressive airflow obstruction of the peripheral airways, associated with lung inflammation, emphysema and mucus hypersecretion. Different approaches to mimic COPD have been developed but are limited in comparison to models of allergic asthma. COPD models usually do not mimic the major features of human COPD and are commonly based on the induction of COPD-like lesions in the lungs and airways using noxious inhalants such as tobacco smoke, nitrogen dioxide, or sulfur dioxide. Depending on the duration and intensity of exposure, these noxious stimuli induce signs of chronic inflammation and airway remodelling. Emphysema can be achieved by combining such exposure with instillation of tissue-degrading enzymes. Other approaches are based on genetically-targeted mice which develop COPD-like lesions with emphysema, and such mice provide deep insights into pathophysiological mechanisms. Future approaches should aim to mimic irreversible airflow obstruction, associated with cough and sputum production, with the possibility of inducing exacerbations.
Chronic obstructive pulmonary disease; COPD; asthma; animal; mice; rat; guinea pig; tobacco smoke; nitrogen dioxide; sulfur dioxide
Several epidemiologic studies have found that smokers with chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, have an increased risk of lung cancer compared to smokers without COPD. We have shown a causal role for COPD-like airway inflammation in lung cancer promotion in the CCSPCre/LSL–K-rasG12D mouse model (CC-LR). In contrast, existing epidemiologic data do not suggest any definite association between allergic airway inflammation and lung cancer. To test this, CC-LR mice were sensitized to ovalbumin (OVA) then challenged with an OVA aerosol weekly for eight weeks. This resulted in eosinophilic lung inflammation associated with increased levels of T helper 2 cytokines and mucous metaplasia of airway epithelium, similar to what is seen in asthma patients. However, this type of inflammation did not result in a significant difference in lung surface tumor number (49 ± 9 in OVA vs 52 ± 5 in control), in contrast to a 3.2-fold increase with COPD-like inflammation. Gene expression analysis of NTHi-treated lungs showed up-regulation of a different profile of inflammatory genes, including interleukin 6 (IL-6), compared to OVA-treated lungs. Therefore, to determine the causal role of cytokines that mediate COPD-like inflammation in lung carcinogenesis, we genetically ablated IL-6 in CC-LR mice. This not only inhibited intrinsic lung cancer development (1.7-fold), but also inhibited the promoting effect of extrinsic COPD-like airway inflammation (2.6-fold). We conclude that there is a clear specificity for the nature of inflammation in lung cancer promotion, and IL-6 has an essential role in lung cancer promotion.
lung cancer; inflammation; COPD; asthma; IL-6
Patients with bronchitis type of chronic obstructive pulmonary disease (COPD) have raised vascular endothelial growth factor (VEGF) levels in induced sputum. This has been associated with the pathogenesis of COPD through apoptotic and oxidative stress mechanisms. Since, chronic airway inflammation is an important pathological feature of COPD mainly initiated by cigarette smoking, aim of this study was to assess smoking as a potential cause of raised airway VEGF levels in bronchitis type COPD and to test the association between VEGF levels in induced sputum and airway inflammation in these patients.
14 current smokers with bronchitis type COPD, 17 asymptomatic current smokers with normal spirometry and 16 non-smokers were included in the study. VEGF, IL-8, and TNF-α levels in induced sputum were measured and the correlations between these markers, as well as between VEGF levels and pulmonary function were assessed.
The median concentrations of VEGF, IL-8, and TNF-α were significantly higher in induced sputum of COPD patients (1,070 pg/ml, 5.6 ng/ml and 50 pg/ml, respectively) compared to nonsmokers (260 pg/ml, 0.73 ng/ml, and 15.4 pg/ml, respectively, p < 0.05) and asymptomatic smokers (421 pg/ml, 1.27 ng/ml, p < 0.05, and 18.6 pg/ml, p > 0.05, respectively). Significant correlations were found between VEGF levels and pack years (r = 0.56, p = 0.046), IL-8 (r = 0.64, p = 0.026) and TNF-α (r = 0.62, p = 0.031) levels both in asymptomatic and COPD smokers (r = 0.66, p = 0.027, r = 0.67, p = 0.023, and r = 0.82, p = 0.002, respectively). No correlation was found between VEGF levels in sputum and pulmonary function parameters.
VEGF levels are raised in the airways of both asymptomatic and COPD smokers. The close correlation observed between VEGF levels in the airways and markers of airway inflammation in healthy smokers and in smokers with bronchitis type of COPD is suggestive of VEGF as a marker reflecting the inflammatory process that occurs in smoking subjects without alveolar destruction.
Asthma and chronic obstructive pulmonary disease (COPD) are complex genetic diseases that cause considerable morbidity and mortality worldwide. Genetic variability interacting with environmental and ethnic factors is presumed to cause tobacco smoke susceptibility and to influence asthma severity. A disintegrin and metalloproteinase 33 (ADAM33) and matrix metalloproteinase‐9 (MMP9) appear to have important roles in asthma and COPD pathogenesis. ADAM33 and MMP9 genetic alterations could possibly contribute to the establishment and progression of these multifactorial diseases, although their association with the clinical phenotypes has not yet been elucidated. However, the occurrence of these alterations does not always result in clear disease, implying that either they are an epiphenomenon or they are in proximity to the true causative alteration. This review summarises the most recent literature dealing with the genetic variations of metalloproteinases and outlines their potential pathogenetic outcome.
ADAM33; asthma; COPD; genes; metalloproteinases; polymorphisms
Persistent inflammation is often present in patients with lung diseases such as chronic obstructive pulmonary diseases (COPD) and pulmonary hypertension. Circulatory leukocyte migration through the lung vascular endothelium contributes to the structural destruction and remodeling seen in these chronic lung diseases. An inflammatory chemokine CX3CL1/fractalkine is associated with inflammatory lung diseases. Membrane-anchored CX3CL1 serves as an adhesion molecule to capture subsets of mononuclear leukocytes that express the sole receptor, CX3CR1. The extracellular chemokine domain of CX3CL1 can be cleaved/shed by a disintegrin and metalloproteinase domain (ADAM) from stimulus-exposed cells. Soluble CX3CL1 chemoattracts and activates CX3CR1+ leukocytes such as CD8+, CD4+, and γδ T lymphocytes, natural killer cells, dendritic cells, and monocytes/macrophages. CX3CR1+ leukocyte attachment to and migration through the lung vascular endothelium lead to mononuclear cell accumulation in the lung vessel walls and parenchyma. Infiltrated CX3CR1+ immune cells can release mediators to induce injury, stimulate proliferation, and/or chemoattract inflammatory cells. This contributes to structural destruction and remodeling in the development of inflammatory lung diseases. Limited clinical success in treating chronic pulmonary diseases-associated lung functional decline indicates the urgency and significance of understanding upstream signaling that triggers inflammation. This article reviews the advances in the CX3CL1-CX3CR1 axis-mediated modulation of mononuclear leukocyte adhesion and migration in inflammatory lung diseases such as COPD and pulmonary hypertension. Better understanding of the constant flow of circulating leukocytes into the lung vessel wall and parenchyma will help set a stage for the development of novel therapeutic approaches to treat or even cure chronic lung diseases including COPD and pulmonary hypertension.
Chemokine; fractalkine; inflammation; pulmonary; COPD; endothelium; vasculature
Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation. Cigarette smoke has been considered a major player in the pathogenesis of COPD. The inflamed airways of COPD patients contain several inflammatory cells including neutrophils, macrophages,T lymphocytes, and dendritic cells (DCs). The relative contributions of these various inflammatory cells to airway injury and remodeling are not well documented. In particular, the potential role of DCs as mediators of inflammation in the smoker's airways and COPD patients is poorly understood. In the current study we analyzed the effects of cigarette smoke extract on mouse bone marrow derived DC and the production of chemokines and cytokines were studied. In addition, we assessed CSE-induced changes in cDC function in the mixed lymphocyte reaction (MLR) examining CD4+ and CD8+ T cell proliferation. Cigarette smoke extract induces the release of the chemokines CCL3 and CXCL2 (but not cytokines), via the generation of reactive oxygen species (ROS). In a mixed-leukocyte reaction assay, cigarette smoke-primed DCs potentiate CD8+T cell proliferation via CCL3. In contrast, proliferation of CD4+T cells is suppressed via an unknown mechanism. The cigarette smoke-induced release of CCL3 and CXCL2 by DCs may contribute to the influx of CD8+T cells and neutrophils into the airways, respectively.
Chronic obstructive pulmonary disease (COPD), usually caused by tobacco smoking, is one of the leading causes of morbidity and mortality. Smoking cessation at an early stage of the disease usually stops further progression. A study was undertaken to determine if diagnosis of airway obstruction was associated with subsequent success in smoking cessation, as advised by a physician.
4494 current smokers (57.4% men) with a history of at least 10 pack‐years of smoking were recruited from 100 000 subjects screened by spirometric testing for signs of airway obstruction. At the time of screening all received simple smoking cessation advice. 1177 (26.2%) subjects had airway obstruction and were told that they had COPD and that smoking cessation would halt rapid progression of their lung disease. No pharmacological treatment was proposed. After 1 year all subjects were invited for a follow up visit. Smoking status was assessed by history and validated by exhaled carbon monoxide level.
Nearly 70% attended a follow up visit (n = 3077): 61% were men, mean (SD) age was 52 (10) years, mean (SD) tobacco exposure 30 (17) pack‐years, and 33.3% had airway obstruction during the baseline examination. The validated smoking cessation rate in those with airway obstruction was 16.3% compared with 12.0% in those with normal spirometric parameters (p = 0.0003). After correction for age, sex, nicotine dependence, number of cigarettes smoked daily, and lung function, success in smoking cessation was predicted by lower lung function, lower nicotine dependence, and lower tobacco exposure.
Simple smoking cessation advice combined with spirometric testing resulted in good 1 year cessation rates, especially in subjects with airway obstruction.
lung function testing; counselling; smoking cessation; chronic obstructive pulmonary disease
Lung cancer is the leading cause of cancer deaths in the United States. In addition to genetic abnormalities induced by cigarette smoke, several epidemiologic studies have found that smokers with chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lungs, have an increased risk of lung cancer (1.3- to 4.9-fold) compared to smokers without COPD. This suggests a link between chronic airway inflammation and lung carcinogenesis, independent of tobacco smoke exposure. We studied this association by assaying the inflammatory impact of products of nontypeable Haemophilus influenzae, which colonizes the airways of patients with COPD, on lung cancer promotion in mice with an activated K-ras mutation in their airway epithelium. Two new mouse models of lung cancer were generated by crossing mice harboring the LSL–K-rasG12D allele with mice containing Cre recombinase inserted into the Clara cell secretory protein (CCSP) locus, with or without the neomycin cassette excised (CCSPCre and CCSPCre-Neo, respectively). Lung lesions in CCSPCre-Neo/LSL–K-rasG12D and CCSPCre/LSL–K-rasG12D mice appeared at 4 and 1 month of age, respectively, and were classified as epithelial hyperplasia of the bronchioles, adenoma, and adenocarcinoma. Weekly exposure of CCSPCre/LSL–K-rasG12D mice to aerosolized nontypeable Haemophilus influenzae lysate from age 6–14 weeks resulted in neutrophil/macrophage/CD8 T-cell–associated COPD-like airway inflammation, a 3.2-fold increase in lung surface tumor number (156 ± 9 versus 45 ± 7), and an increase in total lung tumor burden. We conclude that COPD-like airway inflammation promotes lung carcinogenesis in a background of a G12D-activated K-ras allele in airway secretory cells.
K-ras; lung cancer; inflammation
Obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) are two diseases that often coexist within an individual. This coexistence is known as overlap syndrome and is the result of chance rather than a pathophysiological link. Although there are claims of a very high incidence of OSAS in COPD patients, recent studies report that it is similar to the general population. Overlap patients present sleep-disordered breathing associated to upper and lower airway obstruction and a reduction in respiratory drive. These patients present unique characteristics, which set them apart from either COPD or OSAS patients. COPD and OSAS are independent risk factors for cardiovascular events and their coexistence in overlap syndrome probably increases this risk. The mechanisms underlying cardiovascular risk are still unclear, but may involve systemic inflammation, endothelial dysfunction, and tonic elevation of sympathetic neural activity. The treatment of choice for overlap syndrome in stable patients is CPAP with supplemental oxygen for correction of upper airway obstructive episodes and hypoxemia during sleep.
chronic obstructive pulmonary disease; obstructive sleep apnea syndrome; overlap syndrome; sleep; cardiovascular disease
oxide (NO) is involved in inflammation and host defence of the lung. It
has been found in increased concentrations in the airways in asthmatic
subjects but its levels in patients with chronic obstructive pulmonary
disease (COPD) have not been investigated. A study was undertaken to
determine whether markers of NO metabolism (NO in exhaled air, iNOS
expression in sputum cells, and nitrite + nitrate
(NO2-/NO3-) in sputum
supernatant) are increased in subjects with COPD, and whether they
correlate with inflammatory indices in induced sputum. The associations
of these markers with smoking were also assessed.
subjects with COPD (median age 66 years, median forced expiratory
volume in one second (FEV1) 63% predicted, eight current
smokers) and 16 healthy subjects (median age 63 years, median
FEV1 113% predicted, eight current smokers) participated in the study. NO was measured during tidal breathing and sputum was
induced by inhalation of hypertonic saline.
were observed between subjects with COPD and healthy controls in
exhaled NO excretion rate (median 5.15 and 6.25 nmol/min), sputum
macrophage iNOS expression (14% and 12%), and sputum supernatant
NO2-/NO3- (46 and
73 µM). NO in exhaled air correlated with the percentage of sputum
eosinophils in patients with COPD (rho = 0.65, p = 0.009) but not in
healthy individuals. Exhaled NO and supernatant
NO2-/NO3- levels were
lower in healthy smokers than in healthy non/ex-smokers.
findings indicate that NO metabolism is not increased in patients with
stable COPD. The close association between exhaled NO levels and sputum
eosinophils suggests a role for NO in airway inflammation in COPD.
Studies performed during exacerbations may clarify this role.
Chronic obstructive pulmonary disease (COPD) is characterized physiologically by expiratory flow limitation and pathologically by alveolar destruction and enlargement and small and large airway inflammation and remodeling. An imbalance between protease and antiprotease activity in the lung is proposed as the major mechanism resulting in emphysema. The imbalance is mostly due to an increase in the numbers of alveolar macrophages and neutrophils. Emphysema can also develop from increased alveolar wall cell death and/or failure in alveolar wall maintenance. Chronic inflammation and increased oxidative stress contribute to increased destruction and/or impaired lung maintenance and repair. Genetic factors may play an important role in disease susceptibility because only a minority of smokers develops emphysema. Recent literature implicates surfactant instability, malnutrition, and alveolar cell apoptosis as possible etiologies. Identification of cellular and molecular mechanisms of COPD pathogenesis is an area of active, ongoing research that may help to determine therapeutic targets for emphysema.
emphysema; apoptosis; protease–antiprotease balance; oxidative stress; hypoxemia