Biopsy neutrophilia, neutrophil chemokine and receptor gene expression in severe exacerbations of chronic obstructive pulmonary disease

Should patients with acute exacerbation of chronic bronchitis be treated with antibiotics? Advantages of the use of fluoroquinolones

The pathological changes in chronic bronchitis (CB) produce airflow obstruction, reduce the effectiveness of the mucocilliary drainage system and lead to bacterial colonisation of bronchial secretion. The presence of bacteria induces an inflammatory response mediated by leukocytes. There is a direct relationship between the degree of impairment of the mucocilliary drainage system, the density of bacteria in mucus and the number of leukocytes in the sputum. Purulent sputum is a good marker of a high bacterial load. Eventually, if the number of leukocytes is high, their normal activity could decrease the effectiveness of the drainage system, increase the bronchial obstruction and probably damage the lung parenchyma. Whenever the density of bacteria in the bronchial lumen is >or=10(6) CFU/mL, there is a high probability that the degree of inflammatory response will lead to a vicious cycle which in turn tends to sustain the process. This situation can arise during the clinical course of any acute exacerbation of CB, independently of its aetiology, provided the episode is sufficiently severe and/or prolonged. Fluoroquinolones of the third and fourth generation are bactericidal against most microorganisms usually related to acute exacerbations of CB. Their diffusion to bronchial mucus is adequate. When used in short (5-day) treatment they reduce the bacterial load in a higher proportion than is achieved by beta-lactam or macrolide antibiotics given orally. Although the clinical cure rate is similar to that obtained with other antibiotics, the time between exacerbations could be increased.

Anti-inflammatory effects of inhaled corticosteroids in chronic obstructive pulmonary disease: similarities and differences to asthma

Both chronic obstructive pulmonary disease (COPD) and asthma are characterised by the presence of airway inflammation. In the stable disease state, the predominant regulatory and effector cells, and the anatomic focus of the changes associated with airway inflammation, differ between COPD and asthma. However, during exacerbations, these patterns of inflammation become more similar. The benefit of anti-inflammatory therapy with inhaled corticosteroids (ICS) is well established in asthma, whereas the extent of the anti-inflammatory effects of ICS in COPD is debated. Understanding the distinctive and, in exacerbations, the changing patterns of inflammation in COPD and asthma allows a better appreciation of the potential for ICS to target the unique pathophysiology of COPD.

Pulmonary biomarkers in chronic obstructive pulmonary disease

There has been increasing interest in using pulmonary biomarkers to understand and monitor the inflammation in the respiratory tract of patients with chronic obstructive pulmonary disease (COPD). In this Pulmonary Perspective we discuss the merits of the various approaches by reviewing the current literature on pulmonary biomarkers in COPD and underscore the need for more systematic studies in the future. Bronchial biopsies and bronchoalveolar lavage provide valuable information about inflammatory cells and mediators, but are invasive, so that repeated measurements have to be very limited in assessing any interventions. Induced sputum has provided considerable information about the inflammatory process, including mediators and proteinases in COPD, but selectively samples proximal airways and may not closely reflect distal inflammatory processes. Exhaled gases and breath condensate are noninvasive procedures, so repeated measurements are possible, but for some assays the variability is relatively high. There is relatively little information about how any of these biomarkers relate to other clinical outcomes, such as progression of the disease, severity of disease, clinical subtypes, or response to therapy. More information is also needed about the variability in these measurements. In the future, pulmonary biomarkers may be useful in predicting disease progression, indicating disease instability, and in predicting response to current therapies and novel therapies, many of which are now in development.

Role of infection and antimicrobial therapy in acute exacerbations of chronic obstructive pulmonary disease

Over the past several years, the significance of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with chronic airflow obstruction has become increasingly apparent due to the impact these episodes have on the natural history of disease. It is now known that frequent AECOPD can adversely affect a patient's health-related quality of life and short- and long-term pulmonary function. The economic burden of these episodes is also substantial. AECOPDs represent a local and systemic inflammatory response to both infectious and noninfectious stimuli, but the majority of episodes are likely related to bacterial or viral pathogens. Patients with purulent sputum and multiple symptoms are the most likely to benefit from treatment with antibiotics. Antibiotic choice should be tailored to the individual patient, taking into account the severity of the episode and host factors which might increase the likelihood of treatment failure. Current evidence suggests that therapeutic goals not only include resolution of the acute episode, but also prolonging the time to the next event. In the future, preventing exacerbations will likely become increasingly accepted as an additional therapeutic goal in chronic obstructive pulmonary disease patients.

Pathology of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is one of the leading causes of death and morbidity worldwide. Despite intensive investigation, its pathology and pathophysiology are not well understood. The hallmarks of the disease are irreversible airflow limitation and chronic inflammation. Small airway obstruction due to progressive inflammation and fibrosis, and the loss of elastic recoil mediated by elastolysis and apoptosis equally contribute to pathologic changes. However, it is debated to what extent the obstruction of large airways leads to altered lung function. Three morphologic entities are described in the literature under one disease; chronic bronchitis, obstructive bronchiolitis and emphysema may appear in the same patient at the same time. The authors review pathologic changes observed in chronic obstructive pulmonary disease, including acute exacerbations and secondary pulmonary hypertension as severe but common complications of the disease. Furthermore, we detail recent scientific evidences for major cellular and molecular inflammatory pathway activation. These mechanisms result in accelerated apoptosis, remodeling and increased proinflammatory cytokine release. Targeting intracellular pathological changes may lead to the discovery of a new generation of drugs that could reduce chronic obstruction before airway irreversibility is established.

Systemic Immunological Response to Exercise in Patients with Chronic Obstructive Pulmonary Disease: What Does It Mean?

Chronic obstructive pulmonary disease (COPD) is no longer seen as a pulmonary disease, but is increasingly associated with systemic effects with important clinical relevance. Systemic immunological changes in COPD patients are characterized by an increased number of circulating inflammatory cells, functional changes of the inflammatory cells, elevated plasma levels of cytokines, and oxidative stress. Physical exercise induces an abnormal systemic inflammatory and oxidative response in COPD patients, which is seen in both the circulation and the peripheral muscles. Although mechanisms and consequences of these effects are not yet fully understood, they could be harmful in COPD patients by inducing damage or functional changes in, for example, skeletal muscles. Whether these changes of the immune system can also affect the susceptibility to infections in these patients is unknown. The concept of COPD as a systemic rather than only a pulmonary disease also opens new perspectives on the development for new therapeutic interventions. The effects of new antioxidative and anti-inflammatory agents are investigated. A better understanding of the complexity of the systemic effects will aid the development of new therapies and management strategies for patients with COPD.

Respiratory tract mucin genes and mucin glycoproteins in health and disease

This review focuses on the role and regulation of mucin glycoproteins (mucins) in airway health and disease. Mucins are highly glycosylated macromolecules (> or =50% carbohydrate, wt/wt). MUC protein backbones are characterized by numerous tandem repeats that contain proline and are high in serine and/or threonine residues, the sites of O-glycosylation. Secretory and membrane-tethered mucins contribute to mucociliary defense, an innate immune defense system that protects the airways against pathogens and environmental toxins. Inflammatory/immune response mediators and the overproduction of mucus characterize chronic airway diseases: asthma, chronic obstructive pulmonary diseases (COPD), or cystic fibrosis (CF). Specific inflammatory/immune response mediators can activate mucin gene regulation and airway remodeling, including goblet cell hyperplasia (GCH). These processes sustain airway mucin overproduction and contribute to airway obstruction by mucus and therefore to the high morbidity and mortality associated with these diseases. Importantly, mucin overproduction and GCH, although linked, are not synonymous and may follow from different signaling and gene regulatory pathways. In section i, structure, expression, and localization of the 18 human MUC genes and MUC gene products having tandem repeat domains and the specificity and application of MUC-specific antibodies that identify mucin gene products in airway tissues, cells, and secretions are overviewed. Mucin overproduction in chronic airway diseases and secretory cell metaplasia in animal model systems are reviewed in section ii and addressed in disease-specific subsections on asthma, COPD, and CF. Information on regulation of mucin genes by inflammatory/immune response mediators is summarized in section iii. In section iv, deficiencies in understanding the functional roles of mucins at the molecular level are identified as areas for further investigations that will impact on airway health and disease. The underlying premise is that understanding the pathways and processes that lead to mucus overproduction in specific airway diseases will allow circumvention or amelioration of these processes.

Agents against cytokine synthesis or receptors

Various cytokines play a critical role in pathophysiology of chronic inflammatory lung diseases including asthma and chronic obstructive pulmonary disease (COPD). The increasing evidence of the involvement of these cytokines in the development of airway inflammation raises the possibility that these cytokines may become the novel promising therapeutic targets. Studies concerning the inhibition of interleukin (IL)-4 have been discontinued despite promising early results in asthma. Although blocking antibody against IL-5 markedly reduces the infiltration of eosinophils in peripheral blood and airway, it does not seem to be effective in symptomatic asthma, while blocking IL-13 might be more effective. On the contrary, anti-inflammatory cytokines themselves such as IL-10, IL-12, IL-18, IL-23 and interferon-gamma may have a therapeutic potential. Inhibition of TNF-alpha may also be useful in severe asthma or COPD. Many chemokines are also involved in the inflammatory response of asthma and COPD through the recruitment of inflammatory cells. Several small molecule inhibitors of chemokine receptors are now in development for the treatment of asthma and COPD. Antibodies that block IL-8 reduce neutrophilic inflammation. Chemokine CC3 receptor antagonists, which block eosinophil chemotaxis, are now in clinical development for asthma therapy. As many cytokines are involved in the pathophysiology of inflammatory lung diseases, inhibitory agents of the synthesis of multiple cytokines may be more useful tools. Several such agents are now in clinical development.

Association of IL8, CXCR2 and TNF-alpha polymorphisms and airway disease

Chronic obstructive pulmonary disease (COPD) is a disease characterised by inflammation of the peripheral airways involving many inflammatory cells and mediators. IL8 is an important inflammatory mediator that is responsible for the migration and activation of neutrophils. Cellular activity of IL8 is mediated by the receptor CXCR2, and transcription of IL8 is controlled by the cytokine tumour necrosis factor (TNFalpha). The aim of our study was to investigate the influence of single nucleotide polymorphisms in IL8, CXCR2 and TNF-alpha on lung function and respiratory symptoms in subjects from Melbourne, Australia. A total of 1,232 participants completed a detailed respiratory questionnaire, spirometry and measurement of gas transfer. Genotyping for the IL8 -251 T-->A, CXCR2 +785C-->T and TNF-alpha -308G-->A polymorphisms was performed using the tetra-primer ARMS-PCR method. The TNF-alpha A allele was associated with a reduced FEF(25-75) (P = 0.03). Inheritance of the CXCR2 T allele was associated with significantly higher diffusing capacity (P = 0.03) and FEF(25-75) (P = 0.02). No association with the IL8 -251 polymorphism was found. Our results suggest that TNF-alpha is associated with COPD-related phenotypes and the CXCR2 +785 SNP may be important in protecting against pulmonary inflammation. These genes may be important candidates in the modulation of the inflammatory response in the airways.

Combination therapy: Synergistic suppression of virus-induced chemokines in airway epithelial cells

Viruses are associated with the majority of exacerbations of asthma and chronic obstructive pulmonary disease. Virus induction of neutrophil and lymphocyte chemokines in bronchial epithelium is important in exacerbation pathogenesis. Combined corticosteroid/beta2 agonists synergistically suppress airway smooth muscle chemokine production. Because bronchial epithelium expresses glucocorticoid and beta2 receptors, we investigated whether combination therapy can synergistically suppress rhinovirus-induced bronchial epithelial cell neutrophil (CXCL5, CXCL8) and lymphocyte (CCL5, CXCL10) chemokine production. We investigated modulation of rhinovirus- and IL-1beta-induced bronchial epithelial cell chemokine production by salmeterol and fluticasone propionate, used at therapeutic concentrations, alone and in combination. After 1 h pretreatment, combined treatment significantly inhibited rhinovirus 16, 1B, and IL-1beta-induced CCL5 and CXCL8 protein and mRNA production in BEAS-2B cells compared with fluticasone alone. When used 4 h after treatment, the combination significantly reduced virus-induced CCL5 but not CXCL8. Salmeterol alone had no effect; therefore, this inhibition was synergistic. Kinetic analysis demonstrated that combination therapy reduced by 5-fold the concentration of corticosteroid required to inhibit CXCL8 mRNA expression. In primary cells, salmeterol alone reduced rhinovirus-induced CCL5 and CXCL10 and increased CXCL5 production in a dose-dependent manner but had no effect on CXCL8. Fluticasone alone reduced CCL5, CXCL8, and CXCL10 but had no effect on CXCL5. Combination therapy augmented inhibition of CXCL8, CCL5, and CXCL10 but had no effect on CXCL5. Corticosteroids and beta2 agonists suppress rhinovirus-induced chemokines in bronchial epithelial cells through synergistic and additive mechanisms. This effect was greater for lymphocyte- than for neutrophil-related chemokines.

New anti-inflammatory therapies and targets for asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are diseases of the airways with an underlying inflammatory component. The prevalence and healthcare burden of asthma and COPD is still rising and is predicted to continue to rise in the foreseeable future. Beta-agonists and corticosteroids form the basis of the therapies available to treat asthma. However, the treatments available for COPD, corticosteroids and anticholinergics, reduce the number and severity of exacerbations, but have a limited effect on slowing the progression of the disease. The inflammatory processes underlying the pathology of asthma have received a great deal of attention and more recently, those underlying COPD have begun to be elucidated. This has resulted in the identification of new targets that will allow the development of novel approaches by the pharmaceutical industry, which will be able to focus its efforts in an attempt to provide new and improved therapies to treat these debilitating diseases. The resultant therapies should impinge on the underlying development of these diseases rather than providing symptomatic relief or palliative treatment alone. This review will outline new targets and novel approaches currently under investigation, which may provide opportunities for novel anti-inflammatory therapeutic interventions that slow or halt disease progression in asthma and COPD.

A novel flow cytometric assay of human whole blood neutrophil and monocyte CD11b levels: upregulation by chemokines is related to receptor expression, comparison with neutrophil shape change, and effects of a chemokine receptor (CXCR2) antagonist

RATIONALE

Smokers who develop chronic obstructive pulmonary disease (COPD) have amplified inflammation within their lungs, involving selective tissue accumulation of neutrophils, macrophages and CD8+ T cells. CD11b (Mac-1, alphaMbeta(2)-integrin) is both a complement receptor (CR3) and a cell adhesion molecule present on the surface of peripheral blood leukocytes, and undergoes rapid surface upregulation from preformed cytoplasmic stores on activation. Cellular activation can also trigger chemotaxis and shape change, the activation itself being caused by the binding of chemokines to cell surface receptors.

METHODS

We developed a method of whole blood flow cytometry to measure neutrophil and monocyte CD11b upregulation on CD16+ and CD14+ cells, employing staining with the nuclear dye LDS-751 immediately before flow cytometry. In addition we assessed neutrophil shape change by modified gated autofluorescence with forward scatter (GAFS), this being correlated with chemotactic responses.

RESULTS

In smokers with COPD there was a lower maximal shape change for neutrophils in response to CXCL8 (IL-8) in comparison to healthy smokers (p=0.025), and a trend for lower expression of CD11b and shape change in response to CXCL1 (GRO-alpha). Neutrophils were found to predominantly express chemokine receptors CXCR1 and CXCR2 and respond to CXCL8 with CD11b upregulation, while monocytes express more CCR2 and upregulate CD11b preferentially to CCL2 (MCP-1). A CXCR2 antagonist (SB-656933) was found to inhibit neutrophil CD11b upregulation (IC50=260.7nM) and shape change (IC50=310.5nM) in COPD patients.

CONCLUSIONS

Neutrophils and monocytes participate in inflammatory processes in a range of diseases. These whole blood assays can be employed to monitor activity in disease and perform in vitro and ex vivo assessment of chemokine receptor (CXCR) antagonists.

New treatment regimes for virus-induced exacerbations of asthma

This review will focus on the role of viruses as causes of asthma exacerbations. The article will briefly review the current literature supporting this view, with a special focus on human rhinovirus (RV), the main virus associated with exacerbations of asthma. The review will then refer to possible strategies for treatment, and will include discussion on treatment with specific anti-viral therapy and type I interferon as a treatment for RV. The review will also include a discussion on current therapies for asthma, such as glucocorticosteroid and beta(2) agonist therapy alone and in combination and why this may be relevant to virus-induced exacerbations of asthma. Finally, the potential for future anti-inflammatory/immunomodulatory therapies with a focus on NF-kappaB inhibition will be discussed.

Expression of CXC Chemokine Receptors 1 and 2 in Human Bronchial Epithelial Cells

INTRODUCTION

CXC chemokine receptor 1 (CXCR1) and CXC chemokine receptor 2 (CXCR2) have been shown to play an important role in transepithelial migration of neutrophil granulocytes during inflammation in various tissues. This study investigated the regulation of gene expression and surface expression of CXCR1 and CXCR2 in a human bronchial epithelial cell line (BEAS-2B), as well as in primary bronchial epithelial cells (PBECs) from 10 COPD patients and 10 control subjects.

METHODS AND RESULTS

The transcription expression of CXCR1 and CXCR2 was quantitatively assessed by means of real-time polymerase chain reaction (PCR) under various inflammatory conditions. Flow cytometry was used to measure CXCR1 and CXCR2 surface expression. There was a low baseline expression of CXCR1 and CXCR2 in real-time PCR in PBECs from COPD patients and control subjects as well as in BEAS-2B cells, and no significant regulation occurred under various inflammatory conditions in PBECs and BEAS-2B cells. Furthermore, unstimulated surface expression of CXCR1 and CXCR2 on BEAS-2B cells was very low, and no significant regulation was detectable under time-dependent inflammatory stimulation up to 24 h.

CONCLUSION

Various inflammatory responses that are of potential relevance in COPD pathophysiology do not affect transcription regulation and surface expression of the interleukin-8 receptors CXCR1 and CXCR2 on human bronchial epithelial cells.

Comparative Effects of Salmeterol, Albuterol, and Ipratropium on Normal and Impaired Mucociliary Function in Sheep

STUDY OBJECTIVE

We measured tracheal mucus velocity (TMV), a marker of mucociliary clearance (MCC), in sheep before and for 12 h after treatment with salmeterol, albuterol, ipratropium, or vehicle to determine the effects on normal MCC. We also determined if these agents could reverse the depression in TMV caused by inhaled human neutrophil elastase (HNE), a model of abnormal MCC.

METHODS

Study 1: TMV was measured initially and then for 6 h after metered-dose inhaler treatment with salmeterol (42 microg), albuterol (180 microg), ipratropium bromide (36 microg), or vehicle. After 6 h, the sheep in the albuterol and ipratropium treatment arms were administered a second dose of drug, whereas the salmeterol and vehicle treatment arms received vehicle. TMV was measured for another 6 h. Study 2: Six sheep inhaled HNE aerosol, which significantly reduced TMV by 2 h. At this point, the sheep were treated with either salmeterol, albuterol, ipratropium, or vehicle, and the effects on TMV were measured for another 6 h. This experiment was repeated in four sheep using only salmeterol and albuterol, but the posttreatment measurements were extended to 12 h.

RESULTS

Study 1: Only salmeterol and albuterol increased TMV (p < 0.05) during the initial 6-h period. From 6 to 12 h only, the salmeterol-treated sheep had TMV that remained at or above the initial TMV for the entire time, although both albuterol and ipratropium showed enhancement of TMV compared to vehicle. Study 2: Salmeterol and albuterol reversed the HNE-induced depression in TMV to a similar degree over the 6-h time course. However, the protection afforded by salmeterol was more prolonged than that seen with albuterol if the posttreatment interval was extended to 12 h. Ipratropium and vehicle had no effect.

CONCLUSION

We conclude that salmeterol and albuterol can stimulate normal MCC and reverse HNE-induced mucociliary dysfunction and that salmeterol has a longer duration of action in these models of normal and abnormal MCC.

Toll-like receptor 3 is induced by and mediates antiviral activity against rhinovirus infection of human bronchial epithelial cells

Rhinoviruses (RV) are the major cause of the common cold and acute exacerbations of asthma and chronic obstructive pulmonary disease. Toll-like receptors (TLRs) are a conserved family of receptors that recognize and respond to a variety of pathogen-associated molecular patterns. TLR3 recognizes double-stranded RNA, an important intermediate of many viral life cycles (including RV). The importance of TLR3 in host responses to virus infection is not known. Using BEAS-2B (a human bronchial epithelial cell-line), we demonstrated that RV replication increased the expression of TLR3 mRNA and TLR3 protein on the cell surface. We observed that blocking TLR3 led to a decrease in interleukin-6, CXCL8, and CCL5 in response to poly(IC) but an increase following RV infection. Finally, we demonstrated that TLR3 mediated the antiviral response. This study demonstrates an important functional requirement for TLR3 in the host response against live virus infection and indicates that poly(IC) is not always a good model for studying the biology of live virus infection.

Acute respiratory infection with mouse adenovirus type 1

Studies of the pathogenesis of adenovirus respiratory disease are limited by the strict species-specificity of the adenoviruses. Following intranasal inoculation of adult C57BL/6 mice with mouse adenovirus type 1 (MAV-1), we detected MAV-1 early region 3 (E3) and hexon gene expression in the lungs at 7 days post-infection (dpi). We detected MAV-1 E3 protein in the respiratory epithelium at 7 dpi. We did not detect viral mRNA or protein at 14 dpi, but MAV-1 DNA was detected by PCR at 21 dpi. Chemokine transcript levels increased between 7 and 14 dpi in the lungs of infected mice. MAV-1 infection induced a patchy cellular infiltrate in lungs at 7 and 14 dpi. This is the first report demonstrating the presence of MAV-1 in the respiratory epithelium of infected mice and describing chemokine responses in the lung induced by MAV-1 respiratory infection. MAV-1 infection of mice has the potential to serve as a model for inflammatory changes seen in human adenovirus respiratory disease.

Effect of cigarette smoke exposure in vivo on bronchial smooth muscle contractility in vitro in rats

Cigarette smoking is a risk factor for the development of airway hyperresponsiveness and chronic obstructive pulmonary disease. Little is known concerning the effect of cigarette smoking on the contractility of airway smooth muscle. The current study was performed to determine the responsiveness of bronchial smooth muscles isolated from rats that were subacutely exposed to mainstream cigarette smoke in vivo. Male Wistar rats were exposed to diluted mainstream cigarette smoke for 2 h/d every day for 2 wk. Twenty-four hours after the last cigarette smoke exposure, a marked airway inflammation (i.e., increases in numbers of neutrophils, lymphocytes, and macrophages in bronchoalveolar lavage fluid and peribronchial tissues) was observed. In these subacutely cigarette smoke-exposed animals, the responsiveness of isolated intact (nonpermeabilized) bronchial smooth muscle to acetylcholine, but not to high K+ -depolarization, was significantly augmented when compared with the air-exposed control group. In alpha-toxin-permeabilized bronchial smooth muscle strips, the acetylcholine-induced Ca2+ sensitization of contraction was significantly augmented in rats exposed to cigarette smoke, although the contraction induced by Ca2+ was control level. Immunoblot analyses revealed an increased expression of RhoA protein in the bronchial smooth muscle of rats that were exposed to cigarette smoke. Taken together, these findings suggest that the augmented agonist-induced, RhoA-mediated Ca2+ sensitization may be responsible for the enhanced bronchial smooth muscle contraction induced by cigarette smoking, which has relevance to airway hyperresponsiveness in patients with chronic obstructive pulmonary disease.

Concentration of CCL11, CXCL8 and TNF-alpha in sputum and plasma of patients undergoing asthma or chronic obstructive pulmonary disease exacerbation

Asthma and chronic obstructive pulmonary disease (COPD) are common respiratory illnesses characterized by chronic inflammation of the airways. The characterization of induced or spontaneously produced sputum is a useful technique to assess airway inflammation. In the present study, we compared the concentrations of CCL2, CCL11, CXCL8, and tumor necrosis factor-alpha (TNF-alpha) in plasma and induced sputum of patients with severe asthma or COPD and correlated the levels of these mediators with inflammatory cells in sputum. Asthmatic patients had elevated levels of eosinophils (40.1 +/- 6.24%) in sputum whereas neutrophils (63.3 +/- 4.66%) predominated in COPD patients. The levels of the chemokine CCL11 were markedly increased in sputum (708.7 +/- 330.7 pg/ml) and plasma (716.6 +/- 162.2 pg/ml) of asthmatic patients and correlated with the percentage of eosinophils in induced sputum. The concentrations of CXCL8 (817.0 +/- 105.2 pg/ml) and TNF-alpha (308.8 +/- 96.1 pg/ml) were higher in sputum of COPD patients and correlated with the percentage of neutrophils in induced sputum. There was also an increase in the concentrations of CXCL8 (43.2 +/- 6.8 pg/ml) in sputum of asthmatic patients. These results validate that sputum is a suitable method to assess chemokines and cytokines associated with asthma and COPD. Moreover, the mechanisms involved in the synthesis of CCL11 and CXCL8/TNF-alpha would be helpful to better understand the inflammatory profile associated with asthma and COPD, respectively.

Phosphatidylinositol 3-kinase is required for rhinovirus-induced airway epithelial cell interleukin-8 expression

Rhinovirus (RV) is a common cause of asthma exacerbations. The signaling mechanisms regulating RV-induced airway epithelial cell responses have not been well studied. We examined the role of phosphatidylinositol (PI) 3-kinase in RV-induced interleukin (IL)-8 expression. Infection of 16HBE14o- human bronchial epithelial cells with RV39 induced rapid activation of PI 3-kinase and phosphorylation of Akt, a downstream effector of PI 3-kinase. RV39 also colocalized with cit-Akt-PH, a citrogen-tagged fluorescent fusion protein encoding the pleckstrin homology domain of Akt, indicating that 3-phosphorylated PI accumulates at the site of RV infection. Inhibition of PI 3-kinase and Akt attenuated RV39-induced NF-kappaB transactivation and IL-8 expression. Inhibition of PI 3-kinase also blocked internalization of labeled RV39 into 16HBE14o- cells, suggesting that the requirement of PI 3-kinase for RV39-induced IL-8 expression, at least in part, relates to its role in viral endocytosis.

Nitrosative Stress, Heme Oxygenase-1 Expression and Airway Inflammation During Severe Exacerbations of COPD

STUDY OBJECTIVES

The aim of this study was to examine the relationship between airway inflammation, nitrosative stress, heme-oxygenase expression, and acute severe exacerbations of COPD.

DESIGN

We measured heme oxygenase (HO)-1, inducible nitric oxide (NO) synthase expression and nitrotyrosine formation, as well as eosinophilic cationic protein, myeloperoxidase (MPO), interleukin (IL-8), and granulocyte macrophage-colony stimulating factor levels in induced sputum samples from 12 COPD patients (mean +/- SD; FEV1 40 +/- 14% predicted) at the onset of an acute severe exacerbation of COPD requiring hospital admission and 16 weeks after remission.

RESULTS

We demonstrated increased percentages (p = 0.001) and absolute numbers (p = 0.028) of total nitrotyrosine positive (+ve) inflammatory cells (ie, polymorphonuclear cells and macrophages), increased percentages (p = 0.04) and absolute numbers (p = 0.05) of total HO-1 +ve inflammatory cells, and increased MPO (p = 0.005) and IL-8 levels (p = 0.028) during severe exacerbation compared with the stable state.

CONCLUSIONS

Our results support the hypothesis of an involvement of inflammatory and nitrosative stress in severe COPD exacerbations. Future therapeutic strategies may aim at regulating inflammation and NO synthesis during COPD exacerbations.

Increased Arterial Carboxyhemoglobin Concentrations in Chronic Obstructive Pulmonary Disease

RATIONALE

Exhaled carbon monoxide (CO) and arterial blood carboxyhemoglobin concentrations (Hb-CO) increase in inflammatory pulmonary diseases.

OBJECTIVES

To study whether arterial Hb-CO is useful to monitor disease activity in patients with chronic obstructive pulmonary disease (COPD) who had stopped smoking.

METHODS

We measured arterial Hb-CO, arteriovenous Hb-CO differences, and FEV1 in 58 patients with COPD and 61 ex-smoking control subjects.

RESULTS

Arterial Hb-CO concentrations in patients at stable conditions were higher than those in control subjects (p < 0.0001). Furthermore, the Hb-CO concentrations in patients at the exacerbations (p < 0.0001) were higher than those at the stable conditions. Arterial Hb-CO concentrations in patients at stage III were higher than those in patients at stage II, and the Hb-CO concentrations in patients at stage IV were higher than those in patients at stage III at the stable conditions and exacerbations. Arterial Hb-CO correlated with exhaled CO in patients with COPD at stage II and stage III at the exacerbations. Arterial Hb-CO inversely correlated with the arterial blood partial oxygen pressure and FEV1. Arteriovenous Hb-CO differences in patients at the exacerbations did not differ from those in patients at stable conditions and from those in control subjects. Moreover, arterial Hb-CO correlated with serum C-reactive protein values and serum lipid peroxide concentrations.

CONCLUSIONS

These findings suggest that increased arterial Hb-CO may relate to severity in patients with COPD because of lung and systemic inflammation and production of reactive oxygen species.

Interleukin-10 gene expression in acute virus-induced asthma

RATIONALE

Virus-induced asthma is characterized by marked neutrophil influx and eosinophil degranulation, suggesting a mode of immunopathogenesis different from that of allergen-induced asthma.

OBJECTIVES

This study compared induced sputum cytokine responses in subjects with severe asthma exacerbation and respiratory virus infection with those of patients with stable asthma, healthy control subjects, and virus-infected nonasthmatic subjects.

METHODS

Subject infection status and pulmonary history were established on the basis of common cold and asthma questionnaires, and lung function and atopy tests were performed. Respiratory virus infection was diagnosed by cell culture and direct polymerase chain reaction, using induced sputum. The induced sputum cellular profile was examined and cytokine gene expression was assessed by quantitative real-time polymerase chain reaction.

RESULTS

A respiratory virus was detected in 78% of subjects with acute asthma. Specific viruses detected were rhinovirus (83%), influenza (15%), enterovirus (4%), and respiratory syncytial virus (2%). Virus-infected subjects with acute asthma or no asthma had increased RANTES (regulated on activation, normal T cell expressed and secreted) and macrophage inflammatory protein-1alpha messenger RNAs compared with other groups. Interleukin (IL)-10 mRNA was significantly increased in virus-infected acute asthma and reduced on recovery from acute asthma. IL-5, eotaxin, and IL-8 mRNA transcripts were similar across groups.

CONCLUSIONS

Asthma exacerbation triggered by respiratory virus infection is characterized by increased IL-10 gene expression that may explain the suppressed eosinophil influx in acute asthma. Airway neutrophilia due to respiratory virus infection is associated with chemokine gene expression involving RANTES and macrophage inflammatory protein-1alpha.

Oxidative stress and airway inflammation in severe exacerbations of COPD

BACKGROUND

A study was undertaken to assess both oxidative stress and inflammation in the lungs of patients with chronic obstructive pulmonary disease (COPD) during severe and very severe exacerbations compared with those with stable COPD, healthy smokers, and non-smokers. Two sites within the lungs were compared: the large airways (in sputum) and the peripheral airways (by bronchoalveolar lavage (BAL)).

METHODS

BAL fluid cell numbers and levels of tumour necrosis factor (TNFalpha) and interleukin (IL)-8 were measured as markers of airway inflammation and glutathione (GSH) levels as a marker of antioxidant status. Nuclear translocation of the pro-inflammatory transcription factors nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) were also measured by electromobility shift assay in BAL fluid leucocytes and lung biopsy samples.

RESULTS

Influx of inflammatory cells into the peripheral airways during exacerbations of COPD was confirmed. Increased IL-8 levels were detected in BAL fluid from patients with stable COPD compared with non-smokers and healthy smokers, with no further increase during exacerbations. In contrast, IL-8 levels in the large airways increased during exacerbations. GSH levels were increased in the BAL fluid of smokers (444%) and patients with stable COPD (235%) compared with non-smokers and were reduced during exacerbations (severe 89.2%; very severe 52.3% compared with stable COPD). NF-kappaB DNA binding in BAL leucocytes was decreased in healthy smokers compared with non-smokers (41.3%, n = 9, p<0.001) but did not differ in COPD patients, whereas AP-1 DNA binding was significantly decreased during exacerbations of COPD.

CONCLUSION

There is evidence of increased oxidative stress in the airways of patients with COPD that is increased further in severe and very severe exacerbations of the disease. This is associated with increased neutrophil influx and IL-8 levels during exacerbations.

Haemophilus influenzae from patients with chronic obstructive pulmonary disease exacerbation induce more inflammation than colonizers

RATIONALE

Airway infection with Haemophilus influenzae causes airway inflammation, and isolation of new strains of this bacteria is associated with increased risk of exacerbations in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To determine whether strains of H. influenzae associated with exacerbations cause more inflammation than strains that colonize the airways of patients with COPD.

METHODS

Exacerbation strains of H. influenzae were isolated from patients during exacerbation of clinical symptoms with subsequent development of a homologous serum antibody response and were compared with colonization strains that were not associated with symptom worsening or an antibody response. Bacterial strains were compared using an in vivo mouse model of airway infection and in vitro cell culture model of bacterial adherence and defense gene and signaling pathway activation in primary human airway epithelial cells.

RESULTS

H. influenzae associated with exacerbations caused more airway neutrophil recruitment compared with colonization strains in the mouse model of airway bacterial infection. Furthermore, exacerbation strains adhered to epithelial cells in significantly higher numbers and induced more interleukin-8 release after interaction with airway epithelial cells. This effect was likely mediated by increased activation of the nuclear factor-kappaB and p38 mitogen-activated protein kinase signaling pathways.

CONCLUSIONS

The results indicate that H. influenzae strains isolated from patients during COPD exacerbations often induce more airway inflammation and likely have differences in virulence compared with colonizing strains. These findings support the concept that bacteria infecting the airway during COPD exacerbations mediate increased airway inflammation and contribute to decreased airway function.

Activation of the aryl hydrocarbon receptor increases pulmonary neutrophilia and diminishes host resistance to influenza A virus

Unlike their role in bacterial infection, less is known about the role of neutrophils during pulmonary viral infection. Exposure to pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) results in excess neutrophils in the lungs of mice infected with influenza A virus. TCDD is the most potent agonist for the aryl hydrocarbon receptor (AhR), and exposure to AhR ligands has been correlated with exacerbated inflammatory lung diseases. However, knowledge of the effects of AhR agonists on neutrophils is limited. Likewise, the factors regulating neutrophil responses during respiratory viral infections are not well characterized. To address these knowledge gaps, we determined the in vivo levels of KC, MIP-1alpha, MIP-2, LIX, IL-6, and C5a in infected mouse lungs. Our data show that these neutrophil chemoattractants are generally produced transiently in the lung within 12-24 h of infection. We also report that expression of CD11a, CD11b, CD49d, CD31, and CD38 is increased on pulmonary neutrophils in response to influenza virus. Using AhR-deficient mice, we demonstrate that excess neutrophilia in the lung is mediated by activation of the AhR and that this enhanced neutrophilia correlates directly with decreased survival in TCDD-exposed mice. Although AhR activation results in more neutrophils in the lungs, we show that this is not mediated by deregulation in levels of common neutrophil chemoattractants, expression of adhesion molecules on pulmonary neutrophils, or delayed death of neutrophils. Likewise, exposure to TCDD did not enhance pulmonary neutrophil function. This study provides an important first step in elucidating the mechanisms by which AhR agonists exacerbate pulmonary inflammatory responses.

Differences in airway remodeling between asthma and chronic obstructive pulmonary disease

The functional consequence of asthma and chronic obstructive pulmonary disease (COPD)is airflow limitation, which is mostly reversible in asthma and not fully reversible in COPD. In both diseases, inflammatory conditions are associated with cellular and structural changes,referred to as remodeling, and these structural changes may lead to thickening of the airway wall, thereby promoting airway narrowing and airflow limitation. However, the pattern of infiltrated cells and the pattern of structural changes occur differently in the two diseases. In asthma, CD4+, T lymphocytes, eosinophils, and mast cells are the predominant cells involved,whereas in COPD, CD8+, T lymphocytes, and macrophages are predominantly involved. In severe cases of asthma and COPD, neutrophil infiltration becomes evident. Regarding structural changes, epithelial injury and early thickening of reticular basement membrane are highly characteristic of the airway wall of asthmatics. Increases in airway smooth muscle mass occur in large airways of severe asthmatics and in small airways of patients with COPD. Thickening of the airway wall, goblet cell hyperplasia, mucous gland hypertrophy, and the luminal obstruction caused by inflammatory exudates and mucous are features of both asthma and COPD. Squamous epithelial metaplasia and airway wall fibrosis are commonly observed characteristics of COPD. Destruction and fibrosis of the alveolar wall occur in COPD but not in asthma. The remodeling processes accompanied by chronic inflammatory infiltrates interact in a complex fashion and contribute to the development of airflow limitation in both asthma and COPD.

Phosphodiesterase 4-selective inhibition: novel therapy for the inflammation of COPD

Chronic obstructive pulmonary disease (COPD), which is increasing in prevalence and a leading cause of death worldwide, is characterised by an 'abnormal' inflammatory response. There is a predominance of CD8(+) T cells, CD68(+) macrophages and, in exacerbations-neutrophils, in both conducting airways and lung parenchyma. Smoking is the most common etiological factor leading to COPD and smoking cessation is the most effective approach to the management of COPD, but it does not resolve the underlying inflammation of COPD, which persists, even in ex-smokers. The presence of mucosal inflammation serves as the rationale for anti-inflammatory therapy. However, while there are reductions in the numbers of mast cells following treatment with inhaled steroids, CD8(+), CD68(+) cells and neutrophils are refractory to such treatment, highlighting a need for additional, more targeted interventions. Phosphodiesterase 4 (PDE4) inhibitors are a promising and novel drug class that have potent activity against several key components of the inflammatory process in COPD. A recently published study has shown that the selective PDE4 inhibitor, cilomilast, reduces the numbers of bronchial mucosal CD8(+) and CD68(+) cells and neutrophils. This review focuses on the nature of the inflammation in COPD and considers how selective PDE4 inhibitors may optimize and advance our treatment of this chronic condition.

Cellular and molecular mechanisms in chronic obstructive pulmonary disease: an overview

In the last decade, the analysis of bronchial biopsies and lung parenchyma obtained from chronic obstructive pulmonary disease (COPD) patients compared with those from smokers with normal lung function and non-smokers has provided new insights on the role of the different inflammatory and structural cells, their signalling pathways and mediators, contributing to a better knowledge of the pathogenesis of COPD. This review summarizes and discusses the lung pathology of COPD patients with emphasis on inflammatory cell phenotypes that predominate in different clinical conditions. In bronchial biopsies, a cascade of events takes place during progression from mild-to-severe disease. T lymphocytes, particularly CD8+ cells and macrophages are the prevalent inflammatory cells in the lung of healthy smokers and patients with mild COPD, while total and activated neutrophils predominate in severe COPD. The number of CD4+, CD8+ cells and macrophages expressing nuclear factor-kappa B (NF-kappaB), STAT-4 and IFN-gamma proteins as well as endothelial adhesion molecule-1 in endothelium is increased in mild/moderate disease. In contrast, activated neutrophils (MPO+ cells) and increased nitrotyrosine immunoreactivity develops in severe COPD. In bronchial biopsies obtained during COPD exacerbations, some studies have shown an increased T cell and granulocyte infiltration. Regular treatment with high doses of inhaled glucocorticoids does not significantly change the number of inflammatory cells in bronchial biopsies from patients with moderate COPD. The profile in lung parenchyma is similar to bronchial biopsies. 'Healthy' smokers and mild/moderate diseased patients show increased T lymphocyte infiltration in the peripheral airways. Pulmonary emphysema is associated with a general increase of inflammatory cells in the alveolar septa. The molecular mechanisms driving the lymphocyte and neutrophilic prevalence in mild and severe disease, respectively, needs to be extensively studied. Up-regulation of pro-inflammatory transcription factors NF-kappaB and STAT-4 in mild, activated epithelial and endothelial cells in the more severe disease may contribute to this differential prevalence of infiltrating cells.

Mediators of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major and increasing global health problem that is now a leading cause of death. COPD is associated with a chronic inflammatory response, predominantly in small airways and lung parenchyma, which is characterized by increased numbers of macrophages, neutrophils, and T lymphocytes. The inflammatory mediators involved in COPD have not been clearly defined, in contrast to asthma, but it is now apparent that many lipid mediators, inflammatory peptides, reactive oxygen and nitrogen species, chemokines, cytokines, and growth factors are involved in orchestrating the complex inflammatory process that results in small airway fibrosis and alveolar destruction. Many proteases are also involved in the inflammatory process and are responsible for the destruction of elastin fibers in the lung parenchyma, which is the hallmark of emphysema. The identification of inflammatory mediators and understanding their interactions is important for the development of anti-inflammatory treatments for this important disease.

Particulate phase cigarette smoke increases MnSOD, NQO1, and CINC-1 in rat lungs

Loss of antioxidant/oxidant homeostasis perpetuates inflammation in the lungs and may contribute to the development of COPD and lung cancer. Cigarette smoke (CS) is a primary source of airway oxidative stress and recruits inflammatory cells into smokers' lungs. However, whether these consequences are attributable to a specific or the collective fraction of CS is unknown. We investigated whether the particulate or the gas phase of CS would alter expression of the antioxidant enzymes MnSOD and NQO1 or CINC-1. Sprague Dawley rats were exposed to sham (n = 10) or the particulate phase (PP; n = 10) or gas phase (n = 10) of a Kentucky reference cigarette (1R4F) for 2 h/d for 28 d, after which animals were sacrificed and the lower left lobe of the lung was removed. Immunoblots for SOD and NQO1 revealed that lungs exposed to PP had higher MnSOD/actin and NQO1/actin ratios than either sham-or gas phase-treated animals. In contrast, CuZnSOD remained unchanged. In PP-exposed animals, CINC-1 was 3-fold higher than in sham-exposed animals. The increases in MnSOD and NQO1 protein were associated with increases in total SOD, NQO1, and MPO activities. These data provide evidence that the PP of CS alters oxidant/antioxidant homeostasis in the lungs and participates in the pathogenesis of CS-induced lung diseases such as COPD and cancer.

Changes in sputum T-lymphocyte subpopulations at the onset of severe exacerbations of chronic obstructive pulmonary disease

CD8+ve T-cell responses play a primary role in chronic obstructive pulmonary disease (COPD), but there is little information regarding COPD exacerbations. Sputum induction is a relatively non-invasive and safe method to study airway inflammation. The aim of the study was to investigate changes in airway T-lymphocyte subpopulations at the onset of severe COPD exacerbations via analysis of sputum. Induced sputum samples were collected from 12 COPD patients aged (mean+/-sd) 69+/-7 years, ex-smokers (68+/-23 pack-years), mean FEV1 (%predicted) 40+/-14 at the onset of an acute severe exacerbation requiring hospital admission and 16 weeks after remission of the exacerbation. Inflammatory cells and T-lymphocyte subpopulations (CD4, CD8, Tc1, Tc2) were measured using chemical and double immunocytochemical methods. Increased percentages of sputum neutrophils (P=0.002) and decreased CD4/CD8 and CD8-IFNgamma/CD8-IL4+ve (Tc1/Tc2) cell ratios (P=0.03, P=0.02, respectively) were found at the onset of exacerbation compared to stable state. We conclude that a CD8+ve type-2-mediated immune response is induced at the onset of severe COPD exacerbation.

Role of neutrophils in mucus hypersecretion in COPD and implications for therapy

Airway mucus hypersecretion is a serious and presently untreatable symptom of COPD. Over the past several years, emerging evidence has implicated epidermal growth factor receptor (EGFR) expression and activation in mucin production by airway epithelial (goblet) cells. Activated neutrophils recruited to the airways (and their secreted products) play several key roles in EGFR-dependent mucus hypersecretion: (i) activated neutrophils secrete tumor necrosis factor (TNF)-alpha, which induces EGFR expression in airway epithelial cells; (ii) activated neutrophils release reactive oxygen species, which activate EGFR; (iii) neutrophil elastase cleaves the EGFR proligand, pro-transforming growth factor (TGF)-alpha, releasing mature TGF alpha which activates EGFR in a ligand-dependent fashion; and (iv) neutrophil elastase causes potent goblet cell degranulation. The secretion of active products by neutrophils appears carefully regulated. The local release of neutrophil elastase requires close contact between the neutrophil and another cell, mediated by surface adhesion molecules, thus limiting proteolysis to the immediate pericellular environment. In the airway lumen, neutrophils undergo apoptosis and are cleared by macrophages without releasing their intracellular contents. In contrast, neutrophils that die by necrosis disgorge proteases and reactive oxygen species into the lumen. In COPD, conditions within the airway lumen promote neutrophil necrosis. It is concluded that neutrophil death via necrosis leads to the high concentrations of free neutrophil elastase and reactive oxygen species in the sputum of patients with airway neutrophilia and mucus hypersecretion. Inflammatory cells (neutrophils), molecules (neutrophil elastase and reactive oxygen species), signaling pathways (EGFR), and cellular processes (neutrophil necrosis) contribute to mucus hypersecretion in COPD, and are potential targets for therapy. Interventions that target EGFR, neutrophil elastase, and reactive oxygen species exist and can be evaluated as treatments for neutrophil-dependent mucus hypersecretion.

Neutrophil elastase induces mucus cell metaplasia in mouse lung

Goblet cell hyperplasia in the superficial airway epithelia is a signature pathological feature of chronic bronchitis and cystic fibrosis. In these chronic inflammatory airway diseases, neutrophil elastase (NE) is found in high concentrations in the epithelial lining fluid. NE has been reported to trigger mucin secretion and increase mucin gene expression in vitro. We hypothesized that chronic NE exposure to murine airways in vivo would induce goblet cell metaplasia. Human NE (50 microg) or PBS saline was aspirated intratracheally by male Balb/c (6 wk of age) mice on days 1, 4, and 7. On days 8, 11, and 14, lung tissues for histology and bronchoalveolar lavage (BAL) samples for cell counts and cytokine levels were obtained. NE induced Muc5ac mRNA and protein expression and goblet cell metaplasia on days 8, 11, and 14. These cellular changes were the result of proteolytic activity, since the addition of an elastase inhibitor, methoxysuccinyl Ala-Ala-Pro-Val chloromethylketone (AAPV-CMK), blocked NE-induced Muc5ac expression and goblet cell metaplasia. NE significantly increased keratinocyte-derived chemokine and IL-5 in BAL and increased lung tissue inflammation and BAL leukocyte counts. The addition of AAPV-CMK reduced these measures of inflammation to control levels. These experiments suggest that NE proteolytic activity initiates an inflammatory process leading to goblet cell metaplasia.