Amplification of inflammation in emphysema and its association with latent adenoviral infection

Signal transduction pathways linking the activation of alveolar macrophages with the recruitment of neutrophils to lungs in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major and increasing global health problem. It is predicted by the World Health Organization to become the third most common cause of death and the fifth most common cause of disability in the world by 2020. COPD is a complex inflammatory disease involving several types of inflammatory cells and multiple inflammatory mediators. Although abnormal numbers of inflammatory cells such as macrophages, dendritic cells, neutrophils, and T lymphocytes have been documented in COPD, the relationship between these cell types and the sequence of their appearance and persistence is largely unknown. Alveolar macrophages have been identified as one of the major cell types that plays a key role in orchestrating the inflammatory events associated with the pathophysiology of COPD. One of the major functions of macrophages is the secretion of chemotactic factors and this function is markedly increased on exposure to cigarette smoke (CS). This enhanced release of chemoattractants results in increased lung neutrophil infiltration, which is thought to be a key event in the development of COPD. The molecular basis for this amplified inflammatory response is not very clear, but it could be due to an alteration in signal transduction pathways within the macrophage. Based on existing literature, an attempt has been made to create a comprehensive review of the signal transduction pathways that link the activation of macrophages with the increased recruitment of neutrophils into the airways. Some of the major stimuli that activate macrophages and cause them to secrete chemotactic factors have been identified as CS, wood smoke, ozone, bacterial endotoxin, and proinflammatory cytokines such as interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. These stimuli seem to activate mainly redox-sensitive transcription factors such as nuclear factor (NF)-kappa B and activator protein (AP)-1, both of which play a major role in the synthesis and secretion of chemotactic factors such as IL-8 and leukotriene B(4) (LTB(4)). The pathways involved in the synthesis and secretion of other factors such as macrophage chemotactic protein-1 (MCP-1) and growth-related oncogene-alpha (Gro-alpha) have also been reviewed.

Lung chitinolytic activity and chitotriosidase are elevated in chronic obstructive pulmonary disease and contribute to lung inflammation

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation and emphysematous alveolar destruction. In this study, we have investigated whether chitotriosidase (ChTRase) and acidic mammalian chitinase, two chitinases with chitinolytic activity, are selectively augmented in COPD and contribute to its pathogenesis. We found that smokers with COPD, but not asthmatics, had higher chitinolytic activity and increased levels of ChTRase in bronchoalveolar lavage, more ChTRase-positive cells in bronchial biopsies, and an elevated proportion of alveolar macrophages expressing ChTRase than smokers without COPD or never-smokers. ChTRase accounted for approximately 80% of bronchoalveolar lavage chitinolytic activity, while acidic mammalian chitinase was undetectable. Bronchoalveolar lavage chitinolytic activity and ChTRase were associated with airflow obstruction and emphysema and with the levels of interleukin (IL)-1beta, IL-8, tumor-necrosis factor (TNF)-alpha, and its type II soluble receptor. Tumor necrosis factor-alpha stimulated ChTRase release only from alveolar macrophages from smokers with COPD, and exposure of these cells to ChTRase promoted the release of IL-8, monocyte-chemoattractant protein-1, and metalloproteinase-9. Finally, ChTRase overexpression in the lung of normal mice promoted macrophage recruitment and the synthesis of the murine homologue of IL-8, keratinocyte-derived cytokine, and of monocyte-chemoattractant protein-1. We conclude that pulmonary ChTRase overexpression may represent a novel important mechanism involved in COPD onset and progression.

Prevention of elastase-induced emphysema in placenta growth factor knock-out mice

Background

Although both animal and human studies suggested the association between placenta growth factor (PlGF) and chronic obstructive pulmonary disease (COPD), especially lung emphysema, the role of PlGF in the pathogenesis of emphysema remains to be clarified. This study hypothesizes that blocking PlGF prevents the development of emphysema.

Methods

Pulmonary emphysema was induced in PlGF knock-out (KO) and wild type (WT) mice by intra-tracheal instillation of porcine pancreatic elastase (PPE). A group of KO mice was then treated with exogenous PlGF and WT mice with neutralizing anti-VEGFR1 antibody. Tumor necrosis factor alpha (TNF-α), matrix metalloproteinase-9 (MMP-9), and VEGF were quantified. Apoptosis measurement and immuno-histochemical staining for VEGF R1 and R2 were performed in emphysematous lung tissues.

Results

After 4 weeks of PPE instillation, lung airspaces enlarged more significantly in WT than in KO mice. The levels of TNF-α and MMP-9, but not VEGF, increased in the lungs of WT compared with those of KO mice. There was also increased in apoptosis of alveolar septal cells in WT mice. Instillation of exogenous PlGF in KO mice restored the emphysematous changes. The expression of both VEGF R1 and R2 decreased in the emphysematous lungs.

Conclusion

In this animal model, pulmonary emphysema is prevented by depleting PlGF. When exogenous PlGF is administered to PlGF KO mice, emphysema re-develops, implying that PlGF contributes to the pathogenesis of emphysema.

The role of viruses in the etiology and pathogenesis of common cold

Numerous viruses are able to cause respiratory tract infections. With the availability of new molecular techniques, the number of pathogens detected in specimens from the human respiratory tract has increased. Some of these viral infections have the potential to lead to severe systemic disease. Other viruses are limited to playing a role in the pathogenesis of the common cold syndrome. This chapter focuses on the viral pathogens that are linked to common cold. It is not the intention to comprehensively review all the viruses that are able to cause respiratory tract infections—this would go beyond the scope of this book. The list of viruses that are briefly reviewed here includes rhinoviruses, respiratory syncytial virus, parainfluenza virus, adenovirus, metapneumovirus and coronavirus. Bocavirus is discussed as one example of a newly identified pathogen with a less established role in the etiology and pathogenesis of common cold. Influenza virus does not cause what is defined as common cold. However, influenza viruses are associated with respiratory disease and the clinical picture of mild influenza and common cold frequently overlaps. Therefore, influenza virus has been included in this chapter. It is important to note that a number of viruses are frequently co-detected with other viruses in humans with respiratory diseases. Therefore, the viral etiology and the role of viruses in the pathogenesis of common cold is complex, and numberous questions remain to be answered.

Relationship of pneumocystis antibody response to severity of chronic obstructive pulmonary disease

Pneumocystis colonization has been associated with severity of chronic obstructive pulmonary disease (COPD). The relationship of Pneumocystis antibody status to COPD severity has not been investigated, but antibody levels might relate to both colonization susceptibility and COPD progression. We investigated anti-Pneumocystis antibody titers and airway obstruction in a cohort of patients with COPD. Undetectable anti-Pneumocystis antibody titer was an independent predictor of more-severe airway obstruction, although use of inhaled corticosteroids is a possible confounder of this effect.

Genetic backgrounds of asthma and COPD

Asthma and COPD are complex diseases with strong genetic and environmental components. These common pulmonary diseases have both different and similar clinical features. Molecular genetic techniques are being used to improve understanding of these common late onset disorders. Recently, several genes and genetic loci associated with increased susceptibility to asthma and COPD have been described. Many of these genes are expressed in the lung tissues, indicating that events in lung tissues might drive disease processes. Lung tissues are rich sources of innate danger signals, and an increased understanding of how the lung tissues communicate with the immune system to maintain healthy tissue might provide new insights into the pathogenesis of chronic inflammatory lung diseases in which injury and repair are in disequilibrium. Given that the innate immune system is at the interface between the airways and environmental insults, genetic polymorphisms in genes related to the innate immune system are likely to affect susceptibility to both asthma and COPD. In addition, some findings from genetic studies provide molecular support for the point of view proposed in the Dutch hypothesis regarding the relationship between asthma and COPD, which highlights the complexity of the pathways that can induce small airway disease and suggests that there is a continuum between asthma and COPD.

Targeted treatment in COPD: a multi-system approach for a multi-system disease

Chronic obstructive pulmonary disease is a varied condition when examined from a number of different perspectives including factors which influence disease development, pathological process and clinical features. There may be a complex interaction between the degree by which each of these processes influences the development of COPD and the subsequent clinical phenotype with which the patient presents. The varied host response and subsequent clinical phenotype has generated much interest in recent years. It is possible that failure of treatment to impact on mortality and reverse the disease process is because of the heterogeneous nature of the condition. Identification and targeted treatment of clinical and pathological phenotypes within the broad spectrum of COPD may therefore improve outcome. This article will review previous work which has attempted to phenotype COPD and identify if specific treatment for these phenotypes has been shown to be of benefit. It will examine the work on pathological processes and clinical manifestations, both pulmonary and systemic, and will focus on pharmacological therapies.

Enhanced deposition of low-molecular-weight hyaluronan in lungs of cigarette smoke-exposed mice

Chronic obstructive pulmonary disease (COPD) is characterized by infiltration of inflammatory cells, destruction of lung parenchyma, and airway wall remodeling. Hyaluronan (HA) is a component of the extracellular matrix, and low-molecular-weight (LMW) HA fragments have proinflammatory capacities. We evaluated the presence of HA in alveolar and airway walls of C57BL/6 mice that were exposed to air or cigarette smoke (CS) for 4 weeks (subacute) or 24 weeks (chronic). We measured deposition of the extracellular matrix proteins collagen and fibronectin in airway walls and determined the molecular weight of HA purified from lung tissue. In addition, we studied the expression of HA-modulating genes by RT-PCR. HA staining in alveolar walls was significantly enhanced upon chronic CS exposure, whereas HA levels in the airway walls were already significantly higher upon subacute CS exposure and remained elevated upon chronic CS exposure. This differed from the deposition of collagen and fibronectin, which are only elevated at the chronic time point. In lungs of CS-exposed mice, the molecular weight of HA clearly shifted toward more LMW HA fragments. CS exposure significantly increased the mRNA expression of the HA synthase gene Has3 in total lung tissue, whereas the expression of Has1 was decreased. These in vivo studies in an experimental model of COPD show that CS exposure leads to enhanced deposition of (mostly LMW) HA in alveolar and bronchial walls by altering the expression of HA-modulating enzymes. This may contribute to airway wall remodeling and pulmonary inflammation in COPD.

Oxidized α1-antitrypsin stimulates the release of monocyte chemotactic protein-1 from lung epithelial cells: potential role in emphysema

α1-Antitrypsin (AT) is a major elastase inhibitor within the lung. Oxidation of critical methionine residues in AT generates oxidized AT (Ox-AT), which has a greatly diminished ability to inhibit neutrophil elastase. This process may contribute to the pathogenesis of chronic obstructive pulmonary disease (COPD) by creating a functional deficiency of AT permitting lung destruction. We show here that Ox-AT promotes release of human monocyte chemoattractant protein-1 (MCP-1) and IL-8 from human lung type epithelial cells (A549) and normal human bronchial epithelial (NHBE) cells. Native, cleaved, polymeric AT and secretory leukoproteinase inhibitor (SLPI) and oxidized conformations of cleaved, polymeric AT and SLPI did not have any significant effect on MCP-1 and IL-8 secretion. These findings were supported by the fact that instillation of Ox-AT into murine lungs resulted in an increase in JE (mouse MCP-1) and increased macrophage numbers in the bronchoalveolar lavage fluid. The effect of Ox-AT was dependent on NF-κB and activator protein-1 (AP-1)/JNK. These findings have important implications. They demonstrate that the oxidation of methionines in AT by oxidants released by cigarette smoke or inflammatory cells not only reduces the antielastase lung protection, but also converts AT into a proinflammatory stimulus. Ox-AT generated in the airway interacts directly with epithelial cells to release chemokines IL-8 and MCP-1, which in turn attracts macrophages and neutrophils into the airways. The release of oxidants by these inflammatory cells could oxidize AT, perpetuating the cycle and potentially contributing to the pathogenesis of COPD. Furthermore, these data demonstrate that molecules such as oxidants, antiproteinases, and chemokines, rather than act independently, are likely to interact to cause emphysema.

Respiratory symptoms and airway obstruction in HIV-infected subjects in the HAART era

Background

Prevalence and risk factors for respiratory symptoms and airway obstruction in HIV-infected subjects in the era of highly active antiretroviral therapy (HAART) are unknown. We evaluated respiratory symptoms and measured airway obstruction to identify the impact of HAART and other risk factors on respiratory symptoms and pulmonary function.

Methodology/Principal Findings

Two hundred thirty-four HIV-infected adults without acute respiratory symptoms were recruited from an HIV clinic. All subjects were interviewed and performed spirometry. Multivariate linear and logistic regressions were performed to determine predictors of respiratory symptoms, forced expiratory volume in one second (FEV₁) percent predicted, and FEV₁/forced vital capacity (FEV₁/FVC). Thirty-one percent of subjects reported at least one respiratory symptom. Smoking status (current or former versus never) (odds ratio [OR] = 2.7, 95% confidence interval [CI] = 1.41–5.22, p = 0.003), higher log plasma HIV viral levels (OR = 1.12, 95%CI = 1.02–1.24, p = 0.02), and lower FEV₁/FVC (OR = 1.06 for every 0.01 decrease in FEV₁/FVC, 95%CI = 1.02–1.14, p = 0.001) were independent predictors of respiratory symptoms. Age (p = 0.04), pack-year smoking history (p<0.001), previous bacterial pneumonia (p = 0.007), and HAART use (p = 0.04) were independent predictors of decreased FEV₁/FVC.

Conclusions/Significance

Respiratory symptoms remain common in HIV-infected subjects, especially in those with a smoking history. Subjects who were older, had a greater pack-year history of smoking, or previous bacterial pneumonia had lower FEV₁/FVC ratios. Interestingly, use of HAART was independently associated with a decreased FEV₁/FVC, possibly secondary to an immune response to subclinical infections, increased autoimmunity, or other factors associated with HAART use.

Association of CD40 -1C/T polymorphism in the 5'-untranslated region and chronic obstructive pulmonary disease

BACKGROUND

Chronic inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD). It is influenced by both environmental and genetic factors. CD40 signaling has been linked to pathogenic processes of chronic inflammatory diseases. After interaction with its ligand CD154 (CD40L), CD40 induces a broad variety of chronic inflammatory responses, inducing the release of inflammatory mediators. We investigated whether a CD40 gene (-1C/T) single nucleotide polymorphism (SNP) is associated with COPD in a Chinese population.

METHODS

We analyzed -1C/T SNP of the CD40 gene in 234 patients with COPD, and also in 312 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods.

RESULTS

The frequency of CT and CT+CC of CD40 gene was significantly different from TT in the COPD group compared with the control group (for CT: OR=1.777, 95% CI: 1.117-2.826, p=0.015; for CT+CC: OR=1.614, 95% CI: 1.032-2.526, p=0.035). However, neither the allele frequency of CD40 nor the smoking and clinical stages in CD40 -1C/T genotypes frequency had significant differences between the COPD patients and control.

CONCLUSION

These findings suggest that the CD40 -1C/T polymorphism may contribute to the susceptibility to COPD in a Chinese population.

Prevalence of hepatitis C virus infection in patients with COPD

Some studies have suggested that chronic hepatitis C virus (HCV) infection may induce an accelerated decline of forced expiratory volume in 1 second (FEV1). We performed a cross-sectional study to determine the prevalence of HCV infection in a sample of chronic obstructive pulmonary disease (COPD) patients and in a control group of blood donors. The clinical characteristics of HCV-positive and HCV-negative patients were compared. Anti-HCV antibody was determined and confirmed by HCV-RNA. The prevalence of HCV infection in COPD patients was 7·5% (95% CI 6·52–8·48) and in blood donors was 0·41% (95% CI 0·40–0·42). The HCV-positive patients had a lower FEV1 (34·7±8·6%) and a higher BODE index (median=6) than HCV-negative patients (42·7±16·5%, median=4, respectively) (P=0·011 and 0·027, respectively). Our results suggest a high prevalence of chronic HCV infection in patients with COPD in comparison with the blood donors. HCV-positive patients have a more severe disease.

Role of genetic susceptibility to latent adenoviral infection and decreased lung function

BACKGROUND

Latent adenoviral infection may amplify cigarette smoke-induced lung inflammation and therefore play an important role in the development of chronic obstructive pulmonary disease (COPD). Adenoviruses can evade the human immune response via their 19-kDa protein (19K) which delays the expression of class I human leukocyte antigen (HLA) proteins. The 19K protein shows higher affinity to HLA-B7 and A2 compared with HLA-A1 and A3. The receptor for adenovirus (CXADR) and integrin beta(5) (ITGB5) are host factors which might affect adenovirus infection. Therefore, we investigated the contribution of HLA, CXADR, and ITGB5 genetic variants to the presence of the E1A gene and to level of lung function.

METHODS

Study subjects were assayed for HLA-B7, A1, A2 and A3 by PCR-based assays using allele-specific primers. Polymorphisms of the CXADR and ITGB5 genes were genotyped by PCR-based restriction fragment length polymorphism assays. Detection of adenoviral E1A gene was performed by a real-time PCR TaqMan assay.

RESULTS

E1A positive individuals had a lower FEV(1) compared with E1A negative individuals. However, there was no significant difference in E1A positivity rate between the high (HLA-B7 and A2) and low (HLA-A1 and A3) 19K affinity groups. There was also no significant difference in FEV(1) level between each affinity group. There was no significant difference in E1A positivity rate or lung function among the CXADR and ITGB5 genotypes.

CONCLUSIONS

Genetic variants in HLA, CXADR and ITGB5 do not influence latent adenoviral infections and are not associated with COPD.

Role of the tachykinin NK1 receptor in a murine model of cigarette smoke-induced pulmonary inflammation

Background

The tachykinins, substance P and neurokinin A, present in sensory nerves and inflammatory cells such as macrophages and dendritic cells, are considered as pro-inflammatory agents. Inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and increased tachykinin levels are recovered from the airways of COPD patients. The aim of our study was to clarify the involvement of the tachykinin NK₁ receptor, the preferential receptor for substance P, in cigarette smoke (CS)-induced pulmonary inflammation and emphysema in a mouse model of COPD.

Methods

Tachykinin NK₁ receptor knockout (NK₁-R^-/-) mice and their wild type controls (all in a mixed 129/sv-C57BL/6 background) were subjected to sub acute (4 weeks) or chronic (24 weeks) exposure to air or CS. 24 hours after the last exposure, pulmonary inflammation and development of emphysema were evaluated.

Results

Sub acute and chronic exposure to CS resulted in a substantial accumulation of inflammatory cells in the airways of both WT and NK₁-R^-/- mice. However, the CS-induced increase in macrophages and dendritic cells was significantly impaired in NK₁-R^-/- mice, compared to WT controls, and correlated with an attenuated release of MIP-3α/CCL20 and TGF-β1. Chronic exposure to CS resulted in development of pulmonary emphysema in WT mice. NK₁-R^-/- mice showed already enlarged airspaces upon air-exposure. Upon CS-exposure, the NK₁-R^-/- mice did not develop additional destruction of the lung parenchyma. Moreover, an impaired production of MMP-12 by alveolar macrophages upon CS-exposure was observed in these KO mice. In a pharmacological validation experiment using the NK₁ receptor antagonist RP 67580, we confirmed the protective effect of absence of the NK₁ receptor on CS-induced pulmonary inflammation.

Conclusion

These data suggest that the tachykinin NK₁ receptor is involved in the accumulation of macrophages and dendritic cells in the airways upon CS-exposure and in the development of smoking-induced emphysema. As both inflammation of the airways and parenchymal destruction are important characteristics of COPD, these findings may have implications in the future treatment of this devastating disease.

Peripheral T cell functions correlate with the severity of chronic obstructive pulmonary disease

Adaptive immune processes have been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). We hypothesized that peripheral T cell abnormalities may be present in afflicted patients. We tested this hypothesis by characterizing circulating T cells in COPD patients and correlated these findings with disease severity, smoking status, and use of inhaled glucocorticosteroids (ICS). Compared with normal controls, a lesser proportion of peripheral CD4 T cells from COPD subjects produced IL-10, whereas the CD8 T cells from these patients were more often activated and more frequently produced both IFN-gamma and IL-4. COPD severity was significantly and inversely associated with the proportion of circulating CD4 T cells and directly correlated with CD4 production of IL-2, as well as frequency of CD8 T cell activation and CD8 IFN-gamma production. Adjustments for current smoking status and ICS use by linear regression showed independent, and generally inhibitory, effects of these clinical variables on the abnormal T cell functions of these patients. We conclude that circulating T cells from COPD patients are abnormally activated and elaborate proinflammatory mediators with admixed features of Th1 and Th2 responses. Furthermore, many of these effector processes are significantly correlated with disease severity. These findings further implicate adaptive immune processes in COPD progression and indicate that facile assays of peripheral lymphocytes may provide useful insights into disease mechanisms. Current smoking and ICS use had independent effects on T cell functions among the COPD subjects, illustrating the importance of controlling for clinical parameters as covariates in immunological studies of patients afflicted with this disease.

Change in inflammation in out-patient COPD patients from stable phase to a subsequent exacerbation

Background

Inflammation increases during exacerbations of COPD, but only a few studies systematically assessed these changes. Better identification of these changes will increase our knowledge and potentially guide therapy, for instance by helping with quicker distinction of bacterially induced exacerbations from other causes.

Aim

To identify which inflammatory parameters increase during COPD exacerbations compared to stable disease, and to compare bacterial and non-bacterial exacerbations.

Methods

In 45 COPD patients (37 male/8 female, 21 current smokers, mean age 65, FEV₁ 52% predicted, pack years 38) sputum was collected during a stable phase and subsequently during an exacerbation.

Results

Sputum total cell counts (9.0 versus 7.9 × 10⁶/mL), eosinophils (0.3 versus 0.2 × 106/mL), neutrophils (6.1 versus 5.8 × 10⁶/mL), and lymphocytes (0.07 versus 0.02 × 10⁶/mL) increased significantly during an exacerbation compared to stable disease. A bacterial infection was demonstrated by culture in 8 sputum samples obtained during an exacerbation. These exacerbations had significantly increased sputum total cell and neutrophil counts, leukotriene-B4, myeloperoxidase, interleukin-8 and interleukin-6, and tumor necrosis factor-α (TNF-α) levels, and were also associated with more systemic inflammation compared to exacerbations without a bacterial infection. Sputum TNF-α level during an exacerbation had the best test characteristics to predict a bacterial infection.

Conclusion

Sputum eosinophil, neutrophil, and lymphocyte counts increase during COPD exacerbations. The increase in systemic inflammation during exacerbations seems to be limited to exacerbations caused by bacterial infections of the lower airways. Sputum TNF-α is a candidate marker for predicting airway bacterial infection.

Role of T-lymphocytes and pro-inflammatory mediators in the pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the US and a major worldwide healthcare problem. The pathophysiologic mechanisms that drive development and progression of this disease are complex and only poorly understood. While tobacco smoking is the primary risk factor, other disease processes also appear to play a role. Components of the innate immune system (eg, macrophages and neutrophils) have long been believed to be important in the development of COPD. More recent evidence also suggests involvement of the adaptive immune system in pathogenesis of this disease. Here we will review the literature supporting the participation of T-cells in the development of COPD, and comment on the potential antigenic stimuli that may account for these responses. We will further explore the prospective contributions of T-cell derived mediators that could contribute to the inflammation, alveolar wall destruction, and small airway fibrosis of advanced COPD. A better understanding of these complex immune processes will lead to new insights that could result in improved preventative and/or treatment strategies.

[Pathogenesis of chronic obstructive pulmonary disease]

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by permanent and progressive airway obstruction. Cigarette smoking is the main cause responsible for COPD although only 15 to 25 % of smokers develop COPD. Mechanisms underlying COPD pathogenesis are not fully understood. Structural abnormalities in small airways (bronchioles < 2mm in diameter) are the main determinants of airway obstruction; obstruction of these bronchioles is related to increase in airway wall thickness (associated with peribronchiolar fibrosis) and to plugging by mucus exudates. Alveolar wall destruction (emphysema) also contributes to airway obstruction and to gas exchange abnormalities. Current knowledge related to molecular and cellular mechanisms responsible for these structural modifications are reviewed.

Adenovirus E1A regulates lung epithelial ICAM-1 expression by interacting with transcriptional regulators at its promoter

We focused on the regulation of inflammatory mediator expression by adenovirus E1A in lung epithelial cells and the role of this viral protein in the pathogenesis of chronic obstructive pulmonary disease (COPD). We previously reported that E1A, a well-known regulator of host genes, increased ICAM-1 expression in human bronchial epithelial (HBE) and A549 cells in response to LPS stimulation. In this report, we clarified the mechanism of this regulation. We found NF-kappaB translocation to the nucleus after LPS stimulation in both E1A-positive and -negative HBE cells. ICAM-1 promoter reporter constructs revealed that a mutation in the proximal NF-kappaB binding site completely inhibited increased transcription, whereas the mutation in a distal site did not. We analyzed the participation of E1A in transcriptional complex formation at this promoter using chromatin immunoprecipitation. In E1A-positive HBE and A549 cells, LPS stimulation increased ICAM-1 promoter immunoprecipitation by NF-kappaB p65 and p300 but not activator protein-1 antibodies with a concomitant increase by the E1A antibody. No increase was found in E1A-negative cells except in HBE cells with p65 antibody. The association of E1A with the increased promoter immunoprecipitation with p300 was also observed after TNF-alpha stimulation of A549 cells. These results suggest that adenovirus E1A regulates the ICAM-1 promoter through its proximal NF-kappaB binding site, most likely by interacting with the transcriptional complex that forms at this site. E1A regulation of the LPS response may play a role in acute exacerbations as a consequence of bacterial infections in COPD.

YKL-40 is elevated in patients with chronic obstructive pulmonary disease and activates alveolar macrophages

YKL-40 is a chitin-binding protein that is elevated in patients with various inflammatory conditions associated with ongoing remodeling. We investigated whether the levels of YKL-40 were up-regulated in the circulation and the airways of patients with chronic obstructive pulmonary disease (COPD), and whether it promoted the production of inflammatory mediators from macrophages. Serum, bronchoalveolar lavage (BAL), bronchial biopsies, lung tissue specimens, and alveolar macrophages from never-smokers (n = 15), smokers without COPD (n = 20), and smokers with COPD (n = 30) were assessed for YKL-40 levels and immunolocalization. In addition, YKL-40-induced mediator release from alveolar macrophages was examined. We found that smokers with COPD had elevated levels of YKL-40 in serum (p </= 0.027) and BAL (p </= 0.007), more YKL-40-positive cells in bronchial biopsies (p </= 0.03), and a greater proportion of alveolar macrophages expressing YKL-40 than smokers without COPD or never-smokers. YKL-40 levels in serum and BAL were associated with airflow obstruction (pre-beta(2) agonist forced expiratory volume in 1 s, r(s) = -0.3892, p = 0.0072 and r(s) = -0.5491, p < 0.0001, respectively) and impaired diffusion lung capacity (transfer factor of the lung for carbon monoxide, r(s) = -0.4667, p = 0.002 and r(s) = -0.3854, p = 0.0045, respectively). TNF-alpha stimulated YKL-40 synthesis in alveolar macrophages from smokers with COPD, and exposure of these cells to YKL-40 promoted the release of IL-8, MCP-1, MIP-1alpha, and metalloproteinase-9. We conclude that YKL-40 is up-regulated in COPD, in which it may contribute to tissue inflammation and remodeling by sustaining the synthesis of proinflammatory and fibrogenic chemokines and of metalloproteinases by alveolar macrophages.

Small airway mucous metaplasia and inflammation in chronic obstructive pulmonary disease

Mucous metaplasia is an important determinant of small airway obstruction in COPD. Its relationship to small airway inflammation is poorly defined. We analyzed 4 to 6 small airways in 19 COPD patients, GOLD stages 0-4, from lobectomy or lung volume reduction surgery tissue samples. To identify intracellular mucin, periodic acid fluorescent Schiff's (PAFS) stained slides were imaged by fluorescence microscopy. PAFS+ staining area, basement membrane length (L(BM)), epithelial height and area were measured. Mucin was expressed as a percentage of epithelial area. Mucin volume density (MVD) was calculated as PAFS+ area divided by the product of L(BM) and 4/pi. Airways were Giemsa stained for eosinophils and immunostained with antibodies against CD3, CD4, CD8, CD68, and neutrophil elastase (NE), and the number of positively stained cells/mm(2) was quantified in the airway wall. Mucin percent correlated with CD3(+) cell density (r = 0.553, P < 0.0001), and MVD correlated with CD3(+) (r = 0.570, P < 0.0001) and CD8(+) cell density (r = 0.279, P = 0.016). There were weak negative correlations between mucin percent as well as MVD and CD68(+) cell density (r = -0.270, P = 0.02 and r = -0.245, P = 0.036). There was no relationship between epithelial mucin content and CD4(+), NE(+), or eosinophil cell density. CD3(+) and CD8(+) lymphocytic inflammation is related to small airway mucous metaplasia in COPD and may play a causative role in its development.

Identification of respiratory viruses in asymptomatic subjects: asymptomatic respiratory viral infections

The medical literature of the past 4 decades was searched regarding respiratory virus detection by polymerase chain reaction and conventional methods (culture, antigen detection, serology) in asymptomatic subjects in an attempt to determine the prevalence and clinical significance of such viruses in normal persons.

Airways inflammation and treatment during acute exacerbations of COPD

INTRODUCTION

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.

OBJECTIVES

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.

RESULTS

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.

CONCLUSION

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.

Roles for proteinases in the pathogenesis of chronic obstructive pulmonary disease

Since the early 1960s, a compelling body of evidence has accumulated to show that proteinases play critical roles in airspace enlargement in chronic obstructive pulmonary disease (COPD). However, until recently the causative enzymes and their exact roles in pathologic processes in COPD have not been clear. Recent studies of gene-targeted mice in murine models of COPD have confirmed roles for proteinases not only in airspace enlargement, but also in airway pathologies in COPD. These studies have also shed light on the specific proteinases involved in COPD pathogenesis, and the mechanisms by which these proteinases injure the lung. They have also identified important interactions between different classes of proteinases, and between proteinases and other molecules that amplify lung inflammation and injury. This review will discuss the biology of proteinases and the mechanisms by which they contribute to the pathogenesis of COPD. In addition, I will discuss the potential of proteinase inhibitors and anti-inflammatory drugs as new treatment strategies for COPD patients.

Potential adverse effects of bronchodilators in the treatment of airways obstruction in older people: recommendations for prescribing

Asthma and chronic obstructive pulmonary disease (COPD) are common disorders that are associated with increasing morbidity and mortality in older people. Bronchodilators are used widely in patients with these conditions, but even when used in inhaled form can have systemic as well as local effects. Older people experience more adverse drug effects because of pharmacodynamic and pharmacokinetic changes and particularly drug-drug and drug-disease interactions. Cardiovascular disease is common in older people and beta-adrenoceptor agonists (beta-agonists) have inotropic and chronotropic effects that can increase arrhythmias and cardiomyopathy. They can also worsen or induce myocardial ischaemia and cause electrolyte disturbances that contribute to arrhythmias. Tremor is a well known distressing adverse effect of beta-agonist administration. Long-term beta-agonist use can be associated with tolerance, poor disease control, sudden life-threatening exacerbations and asthma-related deaths. Functional beta2-adrenoceptors are present in osteoblasts, and chronic use of beta-agonists has been implicated in osteoporosis. Inhaled anticholinergics are usually well tolerated but may cause dry mouth, which can be troublesome in older people. Pupillary dilatation, blurred vision and acute glaucoma can occur from escape of droplets from loosely fitting nebulizer masks. Although ECG changes have not been seen in randomized controlled trials of long-acting inhaled anticholinergics, supraventricular tachycardias have been observed in a 5-year randomized controlled trial of ipratropium bromide. Paradoxical bronchoconstriction can occur with inhaled anticholinergics as well as with beta-agonists, but tolerance has not been reported with anticholinergics. Anticholinergic drugs also cause central effects, most notably impairment of cognitive function, and these effects have been noted with inhaled agents. Use of theophylline is limited by its adverse effects, which range from commonly occurring gastrointestinal symptoms to palpitations, arrhythmias and reports of myocardial infarction. Seizures have been reported, but are rare. Theophylline is metabolized primarily by the liver, and commonly interacts with other medications. Its concentration in plasma should be monitored closely, especially in older people. Although many clinical trials have been conducted on bronchodilators in obstructive airways disease, the results of these clinical trials need to be interpreted with caution as older people are often under-represented and subjects with co-morbidities actively excluded from these trials.

Cigarette smoke triggers code red: p21CIP1/WAF1/SDI1 switches on danger responses in the lung

The article by Yao and coworkers in this issue (Am. J. Respir. Cell Mol. Biol. 2008;39:7-18) reveals that the cyclin-dependent kinase inhibitor p21CIP1/WAF1/SDI1 (designated hereafter as p21), which has been linked to cell cycle growth arrest due to stress or danger cell responses, may modulate alveolar inflammation and alveolar destruction, and thus enlightens our present understanding of how the lung senses injury due to cigarette smoke and integrates these responses with those that activate inflammatory pathways potentially harmful to the lung. Furthermore, the interplay of p21 and cellular processes involving cell senescence and the imbalance of cell proliferation/apoptosis may provide us with a more logical explanation of how p21, acting as a sensor of cellular stress, might have such potent and wide roles in lung responses triggered by cigarette smoke. Molecular switches, ontologically designed for the protection of the host, are now hijacked by injurious stresses (such as cigarette smoke), leading to organ damage.

Killer cells in chronic obstructive pulmonary disease

COPD (chronic obstructive pulmonary disease) is a treatable and preventable disease state, characterized by progressive airflow limitation that is not fully reversible. It is a current and growing cause of mortality and morbidity worldwide, with the WHO (World Health Organization) projecting that total deaths attributed to COPD will increase by more than 30% in the next 10 years. The pathological hallmarks of COPD are destruction of the lung parenchyma (pulmonary emphysema), inflammation of the central airways (chronic bronchitis) and inflammation of the peripheral airways (respiratory bronchiolitis). The destructive changes and tissue remodelling observed in COPD are a result of complex interactions between cells of the innate and adaptive immune systems. The focus of the present review is directed towards the role of CD8(+) T-lymphocytes, NK (natural killer) cells and NKT cells (NK T-cells). These three classes of killer cell could all play an important part in the pathogenesis of COPD. The observed damage to the pulmonary tissue could be caused in three ways: (i) direct cytotoxic effect against the lung epithelium mediated by the activities of perforin and granzymes, (ii) FasL (Fas ligand)-induced apoptosis and/or (iii) cytokine and chemokine release. The present review considers the role of these killer cells in COPD.

Immunology of asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are both obstructive airway diseases that involve chronic inflammation of the respiratory tract, but the type of inflammation is markedly different between these diseases, with different patterns of inflammatory cells and mediators being involved. As described in this Review, these inflammatory profiles are largely determined by the involvement of different immune cells, which orchestrate the recruitment and activation of inflammatory cells that drive the distinct patterns of structural changes in these diseases. However, it is now becoming clear that the distinction between these diseases becomes blurred in patients with severe asthma, in asthmatic subjects who smoke and during acute exacerbations. This has important implications for the development of new therapies.

Pneumocystis: a novel pathogen in chronic obstructive pulmonary disease?

Chronic obstructive pulmonary disease (COPD) results in significant morbidity and mortality. Smoking has long been recognized as the primary risk factor for development of COPD, but factors determining the severity or pattern of disease in smokers are largely unknown. Recent interest has focused on the potential role of infectious agents and the associated host response in accelerating progression of airway obstruction or in perpetuating its progression following discontinuation of tobacco exposure. Pneumocystis jirovecii is a fungal pathogen that causes pneumonia in immunocompromised individuals. Recent evidence has linked this organism with COPD. Using sensitive molecular techniques, low levels of Pneumocystis have been detected in the respiratory tract of certain individuals and termed colonization. Several findings support the theory that colonization with Pneumocystis is involved in the "vicious circle" hypothesis of COPD in which colonization with organisms perpetuates an inflammatory and lung remodeling response. Pneumocystis colonization is more prevalent in smokers and in those with severe COPD. The presence of Pneumocystis in the lungs, even at low levels, produces inflammatory changes similar to those seen in COPD, with increases in numbers of neutrophils and CD8(+) lymphocytes. HIV-infected subjects who have had PCP develop permanent airway obstruction, and HIV-infected patients have a high prevalence of both emphysema and Pneumocystis colonization. In addition, a non-human primate model of colonization shows development of airway obstruction and radiographic emphysema. Additional studies are needed to confirm the role of Pneumocystis in the pathogenesis of COPD, given that this agent might be a treatable co-factor in disease progression.

Mechanisms of cigarette smoke-induced COPD: insights from animal models

Cigarette smoke-induced animal models of chronic obstructive pulmonary disease support the protease-antiprotease hypothesis of emphysema, although which cells and proteases are the crucial actors remains controversial. Inhibition of either serine or metalloproteases produces significant protection against emphysema, but inhibition is invariably accompanied by decreases in the inflammatory response to cigarette smoke, suggesting that these inhibitors do more than just prevent matrix degradation. Direct anti-inflammatory interventions are also effective against the development of emphysema, as are antioxidant strategies; the latter again decrease smoke-induced inflammation. There is increasing evidence for autoimmunity, perhaps directed against matrix components, as a driving force in emphysema. There is intriguing but controversial animal model evidence that failure to repair/failure of lung maintenance also plays a role in the pathogenesis of emphysema. Cigarette smoke produces small airway remodeling in laboratory animals, possibly by direct induction of fibrogenic growth factors in the airway wall, and also produces pulmonary hypertension, at least in part through direct upregulation of vasoactive mediators in the intrapulmonary arteries. Smoke exposure causes goblet cell metaplasia and excess mucus production in the small airways and proximal trachea, but these changes are not good models of either chronic bronchitis or acute exacerbations. Emphysema, small airway remodeling, pulmonary hypertension, and mucus production appear to be at least partially independent processes that may require different therapeutic approaches.

The immunopathogenesis of chronic obstructive pulmonary disease: insights from recent research

Chronic obstructive pulmonary disease (COPD) progression is characterized by accumulation of inflammatory mucous exudates in the lumens of small airways, and thickening of their walls, which become infiltrated by innate and adaptive inflammatory immune cells. Infiltration of the airways by polymorphonuclear and mononuclear phagocytes and CD4 T cells increases with COPD stage, but the cumulative volume of the infiltrate does not change. By contrast, B cells and CD8 T cells increase in both the extent of their distribution and in accumulated volume, with organization into lymphoid follicles. This chronic lung inflammation is also associated with a tissue repair and remodeling process that determines the ultimate pathologic phenotype of COPD. Why these pathologic abnormalities progress in susceptible individuals, even after removal of the original noxious stimuli, remains mysterious. However, important clues are emerging from analysis of pathologic samples from patients with COPD and from recent discoveries in basic immunology. We consider the following relevant information: normal limitations on the innate immune system's ability to generate adaptive pulmonary immune responses and how they might be overcome by tobacco smoke exposure; the possible contribution of autoimmunity to COPD pathogenesis; and the potential roles of ongoing lymphocyte recruitment versus in situ proliferation, of persistently activated resident lung T cells, and of the newly described T helper 17 (Th17) phenotype. We propose that the severity and course of acute exacerbations of COPD reflects the success of the adaptive immune response in appropriately modulating the innate response to pathogen-related molecular patterns ("the Goldilocks hypothesis").

Autoantibodies in patients with chronic obstructive pulmonary disease

RATIONALE

Adaptive immune responses are present in patients with chronic obstructive pulmonary disease (COPD), and it has been postulated that these processes could be autoreactive.

OBJECTIVES

To ascertain if humoral autoimmunity could play a role in COPD pathogenesis.

METHODS

Circulating IgG autoantibodies were detected by immunofluorescence and immunoprecipitation. Immunohistochemistry and immunofluorescence were used to evaluate intrapulmonary IgG and complement (C3) deposition in human lung explants. Autoantibody pathogenicity was also investigated with an antibody-dependent cell-mediated cytotoxicity assay.

MEASUREMENTS AND MAIN RESULTS

The prevalence of anti-HEp-2 epithelial cell autoantibodies in 47 smokers/former smokers with COPD (GOLD stages 1-4) was greater than among 8 subjects with a smoking history but normal spirometry and 21 healthy control subjects who had never smoked (68 vs. 13 vs. 10%, respectively; P < 0.0001). Antibodies against primary pulmonary epithelial cells were found in 12 of 12 patients with COPD versus 3 of 12 never-smoked control subjects (P < 0.001). Self-antigens immunoprecipitated from 34 of 35 (97%) of COPD plasmas (vs. 0/12 never-smoked controls). Antibodies against a particular 130-kD autoantigen (n = 7) were associated with decreased body mass index (23.2 +/- 2.1 vs. 29.5 +/- 1.0 kg/m(2), P = 0.007). Intrapulmonary immune complexes were present in six of six and C3 was seen in five of six COPD lung explants, unlike zero of six and one of six normals, respectively. Cytotoxicity of pulmonary epithelial cells by allogeneic mononuclear cells also increased 46% after incubation with COPD plasmas (n = 10), compared with identical treatments with eight normal specimens (P = 0.03).

CONCLUSIONS

IgG autoantibodies with avidity for pulmonary epithelium, and the potential to mediate cytotoxicity, are prevalent in patients with COPD. Autoreactive adaptive immune responses may be important in the etiology of this disease.

[Adenoviral respiratory diseases in healthy children: a study of 116 hospital cases]

Adenoviruses most commonly cause respiratory illness; however, depending on the infecting serotype, they may also cause various other diseases. Diagnosis may be difficult to achieve.The clinical findings for 116 children hospitalised with adenoviral infection were studied retrospectively. In 71 children, the diagnosis was based on detection of adenovirus antigen in the nasopharyngeal specimens and in 71 children on viral culture. The clinical picture of adenoviral infection was characterised by high-grade (mean 39°1C) and prolonged fever (mean duration 4,3 days). Upper respiratory and lower respiratory symptoms were the most common infections. Twelve had been admitted to the hospital due to febrile convulsions, 6 had meningitis. Laboratory findings varied from normal values to values seen in bacterial infections. Thus it was difficult to distinguish adenoviral disease from a bacterial disease. Fifty-nine children were referred to the hospital due to infection unresponsive to antimicrobial therapy.Symptoms of respiratory infection caused by adenovirus may range from the common cold syndrome to pneumonia, croup and bronchiolitis. Adenoviruses can be responsible for severe consequences, even in previously healthy children. Studies of the molecular mechanisms of viral infections of the airways could provide important insights into the nature of the inflammatory process involved in asthma and chronic obstructive pulmonary disease. Most infections are mild and require no therapy or only symptomatic treatment. There are at present time no recognised antiviral agents that are effective in treating serious adenovirus disease. The rapid detection of adenovirus antigen in nasopharygeal specimens proved to have a great clinical value in the diagnosis.

Pathogenesis of chronic obstructive pulmonary disease

The pathogenesis of chronic obstructive pulmonary disease (COPD) encompasses a number of injurious processes, including an abnormal inflammatory response in the lungs to inhaled particles and gases. Other processes, such as failure to resolve inflammation, abnormal cell repair, apoptosis, abnormal cellular maintenance programs, extracellular matrix destruction (protease/antiprotease imbalance), and oxidative stress (oxidant/antioxidant imbalance) also have a role. The inflammatory responses to the inhalation of active and passive tobacco smoke and urban and rural air pollution are modified by genetic and epigenetic factors. The subsequent chronic inflammatory responses lead to mucus hypersecretion, airway remodeling, and alveolar destruction. This article provides an update on the cellular and molecular mechanisms of these processes in the pathogenesis of COPD.

Human T cells stimulate fibroblast-mediated degradation of extracellular matrix in vitro

Several chronic diseases are characterized by inflammation, T cell recruitment and tissue remodelling. We hypothesized that activated T cells may stimulate remodelling of extracellular matrix (ECM) in vitro. Total T cells (CD3+) as well as CD4+ and CD8+ subsets were isolated from peripheral blood and stimulated, after which conditioned media (CM) were obtained. CM was added to human lung fibroblasts in three-dimensional collagen gels and the area of gels was measured daily. Hydroxyproline was determined as a measure of collagen degradation in the gels. Matrix metalloproteinase (MMP) activity in the culture media was analysed by gelatine zymography. Cytokine secretion of stimulated CD4+ and CD8+ T cells was analysed. CD3+ CM augmented collagen gel contraction in a time- and dose-dependent manner (P < 0.0001). CD4+ T cell CM was more potent than CD8+ T cell CM (P < 0.001). CD3+ CM and CD4+ T cell CM, but not CD8+ T cell CM, stimulated fibroblast-mediated collagen degradation and MMP-9 activity. A broad-spectrum MMP-inhibitor added to the culture system inhibited both gel contraction and MMP activity. Activated CD4+ T cells secreted significantly more tumour necrosis factor (TNF) and interleukin (IL)-6 compared to CD8+ T cells. CD3+ CM from patients with chronic obstructive pulmonary disease stimulated fibroblast-mediated collagen gel contraction to the same magnitude as CD3+ CM from healthy controls. In conclusion, activated CD4+ T cells can stimulate fibroblast-mediated degradation of ECM in vitro. This could be a mechanism by which activated T cells stimulate degradation of lung tissue leading to pulmonary emphysema.

Gene expression profiling in patients with chronic obstructive pulmonary disease and lung cancer

RATIONALE

Chronic obstructive lung disease (COPD) is a common and disabling lung disease for which there are few therapeutic options.

OBJECTIVES

We reasoned that gene expression profiling of COPD lungs could reveal previously unidentified disease pathways.

METHODS

Forty-eight human lung samples were obtained from tissue resected from five nonsmokers, 21 GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage 0, 9 GOLD stage 1, 10 GOLD stage 2, and 3 GOLD stage 3 patients. mRNA from the specimens was profiled using Agilent's Functional ID v2.0 array (Agilent, Santa Clara, CA) containing 23,720 sequences.

MEASUREMENTS AND MAIN RESULTS

The gene expression pattern was influenced by the percentage of the sample made up of parenchyma. Gene expression was related to forced expiratory flow between 25 and 75% of forced expiratory volume (FEF(25-75%) % predicted) revealing a signature gene set of 203 transcripts. Genes involved in extracellular matrix synthesis/degradation and apoptosis were among the up-regulated genes, whereas genes that participate in antiinflammatory responses were down-regulated. Immunohistochemistry confirmed expression of urokinase plasminogen activator (PLAU), urokinase plasminogen activator receptor (PLAUR), and thrombospondin (THBS1) by alveolar macrophages and airway epithelial cells. Genes in this pathway have been shown to be involved in the activation of transforming growth factor (TGF)-beta1 and matrix metalloproteinases and are subject to inhibition by SERPINE2. Interestingly, both TGF-beta1 and SERPINE2 have been identified as candidate genes in COPD genetic linkage and association studies.

CONCLUSIONS

The results provide evidence that genes involved in tissue remodeling and repair are differentially regulated in the lungs of obstructed smokers and suggest that they are potential therapeutic targets. Data deposited in GEO at http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE8500.

The effect of smoking cessation and steroid treatment on emphysema in guinea pigs

BACKGROUND

Emphysema induced by cigarette smoking is characterized by an inflammatory process, which is resistant to steroid and remains active in lung tissue long after smoking has stopped. Latent adenoviral infection (Ad5) increases emphysema development and the inflammatory response to cigarette smoke and, in allergic lung inflammation, suppresses anti-inflammatory effects of steroids.

OBJECTIVES

The present study was designed to examine the effect of smoking cessation and steroid treatment on lung emphysema and inflammation in a guinea pig model of emphysema and to determine if latent adenoviral infection induces resistance to the inflammatory effects of steroid.

METHODS

Latent adenovirus or sham infected animals exposed to room air or cigarette smoke for 16 weeks were either sacrificed immediately or treated with dexamethasone or diluent for an additional 5 weeks without smoke exposure. Lung morphometry, inflammatory cells and mediators were studied.

RESULTS

Smoking cessation was associated with an increase in lung surface area and surface area to volume ratio. Smoking cessation was also associated with decreases in lung neutrophils, CD4 cells, and IL-8, RANTES and IFN-gamma mRNAs to control levels. Steroid treatment significantly lowered neutrophils, eosinophils and IFN-gamma mRNA and, while adenoviral infection did not alter these steroid-induced changes, it independently increased airway wall neutrophils and CD8 cells.

CONCLUSION

Smoking cessation decreases lung inflammation and latent adenoviral infection does not induce steroid resistance in this animal model.

Lung tissue and tumour-infiltrating T lymphocytes in patients with non-small cell lung carcinoma and chronic obstructive pulmonary disease (COPD): moderate/severe versus mild stage of COPD

Cytotoxic CD8+ T cells have been suggested to be key players in the pathogenesis of chronic obstructive pulmonary disease (COPD). We wanted to investigate the phenotype of lung tissue T lymphocytes (LTL) and tumour-infiltrating T lymphocytes (TIL) in smokers with peripheral non-small cell lung carcinoma (NSCLC) with moderate/severe versus mild COPD. Lung tissue and tumour samples were obtained from patients with moderate/severe stage of COPD (n = 10) and from patients with mild stage of COPD (n = 7) at lung resection for a solitary peripheral NSCLC, processed and analysed by flow cytometry. The flow-cytometric results showed that lung tissue T cells, regardless of the severity of COPD, were mostly of the activated phenotype, expressed the CXCR3 chemokine receptor characteristic of type 1 T cells, and did neither significantly differ in the expression of activation markers (CD69, CD25 and HLA-DR), differentiation markers (CD27 and CD28) and chemokine receptors (CXCR3 and CCR4) between the selected groups, nor showed any significant correlation with lung function measured as forced expiratory volume in 1 s (FEV1) or TLCO. Compared with LTL, a significantly greater proportion of TIL expressed the activation markers CD69 and CD25, but a lower proportion showed a fully differentiated CD27- 28- phenotype. We conclude that lung LTL patterns are similar in NSCLC patients with moderate/severe or mild stages of COPD, and are not significantly related to lung function. LTL and TIL possess different phenotype characteristics. The majority of tumour tissue T cells are activated, but it seems that their process of differentiation is incomplete.

Effects of 4 months of smoking in mice with ovalbumin-induced airway inflammation

BACKGROUND

The effects of smoking on asthma pathogenesis are complex and not well studied. We have shown recently that 3 weeks of smoking attenuates ovalbumin (OVA)-induced airway inflammation in mice and that 4-6 months of smoking induces emphysema in mice without airway inflammation. Effects of combined long-term smoking and OVA exposure have not been investigated so far.

OBJECTIVE

To study whether long-term smoking affects progression of allergic airway inflammation and/or enhances the development of emphysema in mice.

METHODS

Mice were sensitized to OVA and challenged with saline or OVA aerosols for 6 months. From 2 months onwards, mice were also exposed to air or smoke. Lung tissue was analysed for extent of inflammation, emphysema, remodelling and for cytokine levels, and serum for OVA-specific IgE levels.

RESULTS

Chronic OVA exposure of 6 months resulted in a T helper type 2 (Th2)-type inflammation with increased levels of IL-4, IL-5, IL-6 and infiltration of eosinophils, CD4(+) T cells, macrophages and plasma cells. Smoking induced a Th17-type of airway inflammation, characterized by neutrophils, macrophages, B cells and increased levels of IL-17, IL-6, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor and monocyte chemoattractant protein-1. Concomittant smoking and OVA exposure resulted in inflammation similar to OVA exposure alone. OVA exposure increased IgE levels compared with saline exposure, and smoking did not further increase these levels.

CONCLUSION

We did not find evidence for increased inflammation, IgE levels or emphysema in mice with allergic airway inflammation after 4 months of smoking compared with non-smoking. However, a 4-month exposure to smoke alone did enhance neutrophilic airway inflammation characterized by high pulmonary IL-17 levels. A Th2 inflammatory environment due to OVA exposure may be one explanation as to why no further detrimental effects of smoking on allergic airway inflammation were found.