Cellular and Structural Bases of Chronic Obstructive Pulmonary Disease

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.

Kinase inhibitors and airway inflammation

Kinases are believed to play a crucial role in the expression and activation of inflammatory mediators in the airway, in T-cell function and airway remodelling. Important kinases such as Inhibitor of kappaB kinase (IKK)2, mitogen activated protein (MAP) kinases and phsopho-inositol (PI)3 kinase regulate inflammation either through activation of pro-inflammatory transcription factors such as activating protein-1 (AP-1) and nuclear factor kappaB (NF-kappaB), which are activated in airway disease, or through regulation of mRNA half-life. Selective kinase inhibitors have been developed which reduce inflammation and some characteristics of disease in animal models. Targeting specific kinases that are overexpressed or over active in disease should allow for selective treatment of respiratory diseases. Interest in this area has intensified due to the success of the specific Abelson murine leukaemia viral oncogene (Abl) kinase inhibitor imatinib mesylate (Gleevec) in the treatment of chronic myelogenous leukaemia. Encouraging data from animal models and primary cells and early Phase I and II studies in other diseases suggest that inhibitors of p38 MAP kinase and IKK2 may prove to be useful novel therapies in the treatment of severe asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis and other inflammatory airway diseases.

Modulation of nitric oxide pathways: therapeutic potential in asthma and chronic obstructive pulmonary disease

Nitric oxide (NO) is present in the exhaled breath of humans and other mammalian species. It is generated in the lower airways by enzymes of the nitric oxide synthase (NOS) family, although nonenzymatic synthesis and consumptive processes may also influence levels of NO in exhaled breath. The biological properties of NO in the airways are multiple, complex, and bidirectional. Under physiological conditions, NO appears to play a homeostatic bronchoprotective role. However, its proinflammatory properties could also potentially cause tissue injury and contribute to airway dysfunction in disease states such as asthma and chronic obstructive pulmonary disease (COPD). This article will review the physiological and pathophysiological roles of NO in the airways, discuss the rationale for the use of drugs that modulate NO pathways--nitric oxide synthase inhibitors and NO donors--to treat inflammatory airway diseases, and attempt to predict the likely therapeutic benefit of such agents.

Oxidative stress in asthma and COPD: antioxidants as a therapeutic strategy

Asthma and chronic obstructive pulmonary disease (COPD) are inflammatory lung diseases that are characterized by systemic and chronic localized inflammation and oxidative stress. Sources of oxidative stress arise from the increased burden of inhaled oxidants, as well as elevated amounts of reactive oxygen species (ROS) released from inflammatory cells. Increased levels of ROS, either directly or via the formation of lipid peroxidation products, may play a role in enhancing the inflammatory response in both asthma and COPD. Moreover, in COPD it is now recognized as the main pathogenic factor for driving disease progression and increasing severity. ROS and lipid peroxidation products can influence the inflammatory response at many levels through its impact on signal transduction mechanisms, activation of redox-sensitive transcriptions factors, and chromatin regulation resulting in pro-inflammatory gene expression. It is this impact of ROS on chromatin regulation by reducing the activity of the transcriptional co-repressor, histone deacetylase-2 (HDAC-2), that leads to the poor efficacy of corticosteroids in COPD, severe asthma, and smoking asthmatics. Thus, the presence of oxidative stress has important consequences for the pathogenesis, severity, and treatment of asthma and COPD. However, for ROS to have such an impact, it must first overcome a variety of antioxidant defenses. It is likely, therefore, that a combination of antioxidants may be effective in the treatment of asthma and COPD. Various approaches to enhance the lung antioxidant screen and clinical trials of antioxidant compounds are discussed.

Relation between duration of smoking cessation and bronchial inflammation in COPD

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with airway inflammation. Although smoking cessation improves symptoms and the decline in lung function in COPD, it is unknown whether bronchial inflammation in patients with established COPD varies with the duration of smoking cessation.

METHODS

114 patients (99 men) with COPD of mean (SD) age 62 (8) years, a median (IQR) smoking history of 42 (31-55) pack years, no inhaled or oral corticosteroids, all current or ex-smokers (n = 42, quit >1 month, median cessation duration 3.5 years), post-bronchodilator FEV(1) 63 (9)% predicted, and FEV(1)/IVC 48 (9)% were studied cross sectionally. The numbers of subepithelial T lymphocytes (CD3, CD4, CD8), neutrophils, macrophages, eosinophils, mast cells, and plasma cells were measured in bronchial biopsy specimens (median (IQR)/0.1 mm(2)) using fully automated image analysis.

RESULTS

Ex-smokers with COPD had higher CD3+, CD4+, and plasma cell numbers than current smokers with COPD (149 (88-225) v 108 (61-164), p = 0.036; 58 (32-90) v 40 (25-66), p = 0.023; and 9.0 (5.5-20) v 7.5 (3.1-14), p = 0.044, respectively), but no difference in other inflammatory cells. Short term ex-smokers (<3.5 years) had higher CD4+ and CD8+ cell numbers than current smokers (p = 0.017, p = 0.023; respectively). Conversely, long term ex-smokers (quit > or =3.5 years) had lower CD8+ cell numbers than short term ex-smokers (p = 0.009), lower CD8/CD3 ratios than both current smokers and short-term ex-smokers (p = 0.012, p = 0.003; respectively), and higher plasma cell numbers than current smokers (p = 0.003).

CONCLUSIONS

With longer duration of smoking cessation, CD8 cell numbers decrease and plasma cell numbers increase. This indicates that bronchial T lymphocyte and plasma cell counts, but not other inflammatory cells, are related to duration of smoking cessation in patients with COPD.

Increase in exhaled nitric oxide (eNO) after work-related isocyanate exposure

The objective of this study was to evaluate the role of eNO changes post inhalative isocyanate challenge tests (DeltaeNO) with regard to specific asthmatic reactions and unspecific bronchial hyperresponsiveness (BHR) to predict clinical and subclinical responses of isocyanate workers.

METHODS

55 workers with isocyanate-related respiratory complaints (29 with BHR and 25 without BHR) underwent occupational-type challenge tests. We determined eNO before, during and up to 22 h after diagnostic isocyanate challenge.

RESULTS

The 12 asthmatic responders (22%) in the isocyanate-challenge test showed the highest eNO changes 22 h after challenge as well as a significant association between these changes and BHR. There was a positive association between an eNO increase of > 50% and an asthmatic response when compared to nonresponders with an odds ratio of 6.1; 95% CI 1.4-26.3; P = 0.02. More than half of the employees with BHR (52%) but only 20% of those without BHR developed an eNO rise of > 50% after 22 h. Furthermore, a significant positive association was found between the combination of BHR plus eNO increase of 50% after 22 h and the maximum sRaw change (% of baseline value) during the period 0-22 h after isocyanate exposure. The combination of BHR and eNO increase of > 50% was also associated with clinical symptoms during specific challenge tests (cough, shortness of breath, and/or rhinitis).

DISCUSSION AND CONCLUSIONS

An eNO increase 22 h post isocyanate challenge occurred in two-thirds of responders and in approximately half of nonresponders with BHR but only rarely in those without BHR. The combination of BHR and eNO increase in nonresponders may offer a new diagnostic tool to register subjects with an increased risk of developing occupational asthma. However, a large study group to perform follow-up investigations into this topic would be helpful to emphasize the importance of this finding.

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.

Clinical Pharmacology of Cilomilast

Chronic obstructive pulmonary disease (COPD) is a multicomponent, chronic inflammatory disease of the lungs with systemic complications. The majority of the inflammation occurs in the peripheral airways and lung parenchyma. It is a progressive disease, leading to disability and eventual death, despite conventional therapy. Inflammatory activity can be reduced by increasing intracellular cyclic adenosine-3',5'-monophosphate (cAMP) through inhibition of phosphodiesterase (PDE) IV, the principal PDE isoenzyme within pro-inflammatory cells, including eosinophils, mast cells, macrophages, lymphocytes, neutrophils and epithelial cells. PDE IV inhibition also has other effects, including relaxation of airway smooth muscle, suppression of smooth muscle mitogenesis and modulation of excitatory activity in pulmonary nerves. Cilomilast is a systemically available, second-generation, selective PDE IV inhibitor. It retains the therapeutic activity of the first-generation PDE IV inhibitors but lacks their profound emetic effect. Cilomilast is the first drug to demonstrate a reduction of tissue cells considered central to the ongoing inflammatory process (macrophages and CD8+ lymphocytes) in patients with stable COPD. Cilomilast is completely absorbed following oral administration and has negligible first-pass metabolism. It exhibits linear pharmacokinetics, with low between-subject variability. Cilomilast is highly protein bound (99.4%), but this binding is concentration-independent at clinically relevant doses, and it has a small volume of distribution at steady state (17L). Plasma clearance (approximately 2 L/h) is almost entirely metabolic, through multiple parallel pathways. Its terminal elimination half-life is approximately 6.5 hours and steady state is rapidly achieved with twice-daily administration. The most abundant metabolite, formed by the action of cytochrome P450 2C8, has <10% of the activity of the parent molecule. Cilomilast pharmacokinetics in COPD patients were consistent with those in healthy subjects. Smoking, age and ethnicity had no clinically relevant effects. Total plasma cilomilast pharmacokinetic parameters did not change significantly with renal or hepatic impairment, but concentrations of unbound cilomilast increased with declining renal or hepatic function. Cilomilast had no clinically relevant interactions with a range of drugs likely to be coadministered to patients with COPD, with the exception of erythromycin where concurrent administration with cilomilast was associated with an increased incidence of gastrointestinal adverse events, a pharmacodynamic interaction predicted by their secondary pharmacology. Nausea was the principal adverse reaction seen in healthy subjects taking cilomilast, but this was reduced by administration with food or by use of simple dose-escalation regimens. Cilomilast has not shown a propensity for any of the serious cardiac or neurological adverse effects associated with theophylline. Cilomilast exhibits favourable and predictable pharmacokinetics, has few clinically relevant drug-drug interactions and has demonstrated effects on measures of inflammation of potential benefit in the treatment of COPD. It is generally well tolerated and has not generated safety concerns in any clinical study.

Treatment of airway mucus hypersecretion

Airway mucus hypersecretion is now recognized as a key pathophysiological feature in many patients with asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. Consequently, it is important to develop drugs that inhibit mucus hypersecretion in these susceptible patients. Conventional therapies, including anticholinergics, ss2-adrenoceptor agonists, corticosteroids, mucolytics and macrolide antibiotics, have variable efficacy in inhibiting airway mucus hypersecretion, and are less effective in COPD than in asthma. Novel pharmacotherapeutic targets are being investigated, including inhibitors of nerve activity (e.g. large conductance calcium-activated potassium, BKCa, channel activators), tachykinin receptor antagonists, epoxygenase inducers (e.g. benzafibrate), inhibitors of mucin exocytosis (e.g. anti-myristoylated alanine-rich C kinase substrate (MARCKS), peptide and Munc-18B blockers), inhibitors of mucin synthesis and goblet cell hyperplasia (e.g. epidermal growth factor (EGF), receptor tyrosine kinase inhibitors, p38 mitogen-activated protein (MAP), kinase inhibitors, MAP kinase kinase/extracellular signal-regulated kinase (MEK/ERK), inhibitors, human calcium-activated chloride (hCACL2), channel blockers and retinoic acid receptor-a antagonists), inducers of goblet cell apoptosis (e.g. Bax inducers or Bcl-2 inhibitors), and purinoceptor P(2Y2) antagonists to inhibit mucin secretion or P(2Y2) agonists to hydrate secretions. However, real and theoretical differences delineate the mucus hypersecretory phenotype in asthma from that in COPD. More information is required on these differences to identify specific therapeutic targets which, in turn, should lead to rational design of anti-hypersecretory drugs for treatment of airway mucus hypersecretion in asthma and COPD.

The history of COPD

The evolution of knowledge concerning COPD and its components--emphysema, chronic bronchitis, and asthmatic bronchitis--covers 200 years. The stethoscope and spirometer became important early tools in diagnosis and assessment. Spirometry remains the most effective means of identification and assessment of the course of COPD and responses to therapy, and is grossly underused for this purpose. Knowledge of the pathogenesis, course and prognosis, and new approaches to therapy have dramatically improved our understanding of this important clinical entity. Smoking cessation improves the early course of disease. Long-term oxygen improves the length and quality of life in selected patients with hypoxemia. Surgery benefits a select few. Today, COPD is a steadily growing global healthcare problem, with increasing morbidity and mortality. Early identification and prevention, and treatment of emerging stages of disease through smoking cessation and a growing number of bronchoactive drugs promises to change the outcome.

Chronic cough due to chronic bronchitis: ACCP evidence-based clinical practice guidelines

BACKGROUND

Chronic bronchitis is a disease of the bronchi that is manifested by cough and sputum expectoration occurring on most days for at least 3 months of the year and for at least 2 consecutive years when other respiratory or cardiac causes for the chronic productive cough are excluded. The disease is caused by an interaction between noxious inhaled agents (eg, cigarette smoke, industrial pollutants, and other environmental pollutants) and host factors (eg, genetic and respiratory infections) that results in chronic inflammation in the walls and lumen of the airways. As the disease advances, progressive airflow limitation occurs, usually in association with pathologic changes of emphysema. This condition is called COPD. When a stable patient experiences a sudden clinical deterioration with increased sputum volume, sputum purulence, and/or worsening of shortness of breath, this is referred to as an acute exacerbation of chronic bronchitis as long as conditions other than acute tracheobronchitis are ruled out. The purpose of this review is to present the evidence for the diagnosis and treatment of cough due to chronic bronchitis, and to make recommendations that will be useful for clinical practice.

METHODS

Recommendations for this section of the review were obtained from data using a National Library of Medicine (PubMed) search dating back to 1950, performed in August 2004, of the literature published in the English language. The search was limited to human studies, using the search terms "cough," "chronic bronchitis," and "COPD."

RESULTS

The most effective way to reduce or eliminate cough in patients with chronic bronchitis and persistent exposure to respiratory irritants, such as personal tobacco use, passive smoke exposure, and workplace hazards is avoidance. Therapy with a short-acting inhaled beta-agonist, inhaled ipratropium bromide, and oral theophylline, and a combined regimen of inhaled long-acting beta-agonist and an inhaled corticosteroid may improve cough in patients with chronic bronchitis, but there is no proven benefit for the use of prophylactic antibiotics, oral corticosteroids, expectorants, postural drainage, or chest physiotherapy. For the treatment of an acute exacerbation of chronic bronchitis, there is evidence that inhaled bronchodilators, oral antibiotics, and oral corticosteroids (or in severe cases IV corticosteroids) are useful, but their effects on cough have not been systematically evaluated. Therapy with expectorants, postural drainage, chest physiotherapy, and theophylline is not recommended. Central cough suppressants such as codeine and dextromethorphan are recommended for short-term symptomatic relief of coughing.

CONCLUSIONS

Chronic bronchitis due to cigarette smoking or other exposures to inhaled noxious agents is one of the most common causes of chronic cough in the general population. The most effective way to eliminate cough is the avoidance of all respiratory irritants. When cough persists despite the removal of these inciting agents, there are effective agents to reduce or eliminate cough.

RETRACTED: Effects of Omega-3 Polyunsaturated Fatty Acids on Inflammatory Markers in COPD

BACKGROUND

COPD, the fifth-leading cause of death worldwide, is characterized by chronic inflammation. However, no available agent can effectively cure this inflammation. A dietary supplement containing omega-3 polyunsaturated fatty acids (PUFAs) has anti-inflammatory effects. In this study, we hypothesized that nutritional support with omega-3 PUFA-rich diets may be useful for treating COPD, and we compared the clinical features and inflammatory mediator levels between the COPD patients who received an omega-3 PUFA-rich supplement and those who received a nonrich supplement.

METHODS

Sixty-four COPD patients received 400 kilocalories per day of an omega-3 PUFA-rich supplement (n-3 group) or an omega-3 PUFA-nonrich supplement (n-6 group) for 2 years. We prospectively investigated the clinical features of these patients and measured the levels of inflammatory mediators.

RESULTS

In 6-min walk testing, the dyspnea Borg scale and decrease of arterial oxygen saturation measured by pulse oximetry significantly improved in the n-3 group. Leukotriene B4 levels in serum and sputum and tumor necrosis factor-alpha and interleukin-8 levels in sputum decreased significantly in the n-3 group, while there was no significant change in the n-6 group. Two patients in the n-3 group and three patients in the n-6 group had mild diarrhea, and three patients in the n-3 group and three patients in the n-6 group had nausea; however, their symptoms were controllable and they improved with treatment. With multiple regression analysis, it was proved that the omega-3 PUFA-rich diet significantly contributed to the change in cytokine levels in this study.

CONCLUSION

We suggest nutritional support with an omega-3 PUFA-rich diet as a safe and practical method for treating COPD.

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.

COPD: a dust-induced disease?

Various reports have demonstrated the importance of small airway inflammation in the development of airflow limitation and progression of COPD. This hypothesis proposes that the pathogenesis of COPD mirrors a chronic inhalational dust-induced disease. The putative inorganic dust in cigarette smoke is aluminum silicate or kaolinite, a common component of clay soils. Kaolinite has been recovered in the alveolar macrophages of smokers and has been reported as a constituent of tobacco products. The origin of kaolinite in tobacco products remains unknown, and possible potential sources are proposed. On inhalation, kaolinite deposition in the distal lung may promote macrophage accumulation within the terminal airways leading to a respiratory bronchiolitis. In the susceptible smoker, important genetic, environmental, immunologic, and mechanical factors interact and modulate this small airway inflammation, ultimately leading to the pathologic lesion of emphysema. Further studies into the effects of kaolinite on macrophage function and the subsequent development of respiratory bronchiolitis could lead to prevention of COPD at its precursor lesion.

Survival of COPD patients using inhaled corticosteroids and long-acting beta agonists

We conducted a historical cohort study to examine the relationship between survival and use of inhaled corticosteroids (ICS) and/or long-acting beta agonists (LABA) in patients with chronic obstructive pulmonary disease (COPD). All COPD patients aged 40 years who were enrolled in one of two regional managed care organizations during 1995-2000, and who had 90 days use of an ICS and/or LABA (N=1288) or of a short-acting bronchodilator (N=397), were identified. Of patients treated with ICS and/or LABA, 14.4% died during the follow-up period, as compared to 28.2% of comparison patients (P<0.01). In a Cox proportional hazards model that controlled for age, sex, comorbidities, COPD severity, and asthma status, a reduced risk of death was found for ICS treatment (HR 0.59 [95% CI 0.46-0.78]), LABA (HR 0.55 [0.34-0.89]), and ICS plus LABA treatment (HR 0.34 [0.21-0.56]). A second model that excluded any patient who also had an ICD-9 code for asthma (N=840) still found improved survival among those using the combination of ICS plus LABA (HR 0.35 [CI 0.17-0.71]). Additional analyses that varied the exposure criteria also found a consistent treatment benefit. Inclusion of ICS or bronchodilator treatment during the follow-up period as a time-dependent function appears to negate the survival benefit; however, the underlying assumptions for valid time-dependent modeling are clearly violated in this situation. In conclusion, we found that COPD patients who used ICS alone or in combination with LABA had substantially improved survival even after adjustment for asthma and other confounding factors.

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.

Markers of disease severity in chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVES

Diagnosis and assessment of treatment effect in chronic obstructive pulmonary disease (COPD) have relied primarily on the examination of a complex set of symptoms and the use of spirometry. However, these methods require long periods of assessment to determine whether patients show clinically relevant improvements after intervention. We therefore wanted to determine how existing clinical and laboratory measures change with COPD severity and identify disease markers that can serve as better endpoints for diagnosis and assessment of COPD progression and treatment effect.

METHODS

Using standard COPD keywords and terms, we searched PubMed, ISI Web of Science, and Cochrane Review databases for retrospective and prospective clinical studies published since 1966. We identified 652 studies (n = 146,255) from 1978 to September 2003 based on the availability of spirometric and demographic data, investigation of possible markers, absence of acute exacerbations and co-morbidities, and the withdrawal of standard COPD medication. Central tendencies and dispersions of subject baseline measures were collected according to study sample size, smoking status, and mild, moderate and severe COPD stages. A fixed effect meta-analysis was then conducted on each measure at various disease stages.

RESULTS

Arterial oxygen tension, sputum neutrophils and IL-8, and serum TNF-alpha and C-Reactive Protein showed a trend toward separation between COPD stages. Other measures such as pack-years and St George's Respiratory Questionnaire only distinguished between disease and disease-free states.

CONCLUSIONS

We observed little separation between disease stages for many measures used in COPD diagnosis and clinical trials. This demonstrates the poor sensitivity of such endpoints to define a patient's clinical status and to quantify treatment effect. Therefore, we recommend that longitudinal studies and disease modelling be the primary methods for assessing whether potential markers of disease progression can be used for COPD diagnosis and clinical trials.

Lung volume reduction surgery as a bridge to lung transplantation

Lung volume reduction surgery (LVRS) improves lung function, exercise capacity, and quality of life in patients with advanced emphysema. In some patients with emphysema who are candidates for lung transplantation, LVRS is an alternative treatment option to lung transplantation, or may be used as a bridge to lung transplantation. Generally accepted criteria for LVRS include severe non-reversible airflow obstruction due to emphysema associated with significant evidence of lung hyperinflation and air trapping. Both high resolution computed tomography (CT) scan of the chest and quantitative ventilation/perfusion scan are used to identify lung regions with severe emphysema which would be used as targets for lung resection. Bilateral LVRS is the preferred surgical approach compared with the unilateral procedure because of better functional outcome. Lung transplantation is the preferred surgical treatment in patients with emphysema with alpha1 antitrypsin deficiency and in patients with very severe disease who have homogeneous emphysema pattern on CT scan of the chest or very low diffusion capacity.

Oligoclonal CD4+ T cells in the lungs of patients with severe emphysema

RATIONALE

Within the lungs of patients with severe emphysema, inflammation continues despite smoking cessation. Foci of T lymphocytes in the small airways of patients with emphysema have been associated with disease severity. Whether these T cells play an important role in this continued inflammatory response is unknown.

OBJECTIVE

The aim of this study was to determine if T cells recruited to the lungs of subjects with severe emphysema contain oligoclonal T-cell populations, suggesting their accumulation in response to antigenic stimuli.

METHODS

Lung T-cell receptor (TCR) Vbeta repertoire from eight patients with severe emphysema and six control subjects was evaluated at the time of tissue procurement (ex vivo) and after 2 weeks of culture with interleukin 2 (in vitro). Junctional region nucleotide sequencing of expanded TCR-Vbeta subsets was performed.

RESULTS

No significantly expanded TCR-Vbeta subsets were identified in ex vivo samples. However, T cells grew from all emphysema (n = 8) but from only one of the control lung samples (n = 6) when exposed to interleukin 2 (p = 0.0013). Within the cultured cells, seven major CD4-expressing TCR-Vbeta subset expansions were identified from five of the patients with emphysema. These expansions were composed of oligoclonal populations of T cells that had already been expanded in vivo.

CONCLUSION

Severe emphysema is associated with inflammation involving T lymphocytes that are composed of oligoclonal CD4+ T cells. These T cells are accumulating in the lung secondary to conventional antigenic stimulation and are likely involved in the persistent pulmonary inflammation characteristic of severe emphysema.

Decreased histone deacetylase activity in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation that is greater in patients with advanced disease. We asked whether there is a link between the severity of disease and the reduction in histone deacetylase (HDAC) activity in the peripheral lung tissue of patients with COPD of varying severity. HDAC is a key molecule in the repression of production of proinflammatory cytokines in alveolar macrophages.

METHODS

HDAC activity and histone acetyltransferase (HAT) activity were determined in nuclear extracts of specimens of surgically resected lung tissue from nonsmokers without COPD, patients with COPD of varying severity, and patients with pneumonia or cystic fibrosis. Alveolar macrophages from nonsmokers, smokers, and patients with COPD and bronchial-biopsy specimens from nonsmokers, healthy smokers, patients with COPD, and those with mild asthma were also examined. Total RNA extracted from lung tissue and macrophages was used for quantitative reverse-transcriptase-polymerase-chain-reaction assay of HDAC1 through HDAC8 and interleukin-8. Expression of HDAC2 protein was quantified with the use of Western blotting. Histone-4 acetylation at the interleukin-8 promoter was evaluated with the use of a chromatin immunoprecipitation assay.

RESULTS

Specimens of lung tissue obtained from patients with increasing clinical stages of COPD had graded reductions in HDAC activity and increases in interleukin-8 messenger RNA (mRNA) and histone-4 acetylation at the interleukin-8 promoter. The mRNA expression of HDAC2, HDAC5, and HDAC8 and expression of the HDAC2 protein were also lower in patients with increasing severity of disease. HDAC activity was decreased in patients with COPD, as compared with normal subjects, in both the macrophages and biopsy specimens, with no changes in HAT activity, whereas HAT activity was increased in biopsy specimens obtained from patients with asthma. Neither HAT activity nor HDAC activity was changed in lung tissue from patients with cystic fibrosis or pneumonia.

CONCLUSIONS

Patients with COPD have a progressive reduction in total HDAC activity that reflects the severity of the disease.

Association of current smoking with airway inflammation in chronic obstructive pulmonary disease and asymptomatic smokers

BACKGROUND

Inflammation in the airways and lung parenchyma underlies fixed airway obstruction in chronic obstructive pulmonary disease. The exact role of smoking as promoting factor of inflammation in chronic obstructive pulmonary disease is not clear, partly because studies often do not distinguish between current and ex-smokers.

METHODS

We investigated airway inflammation in sputum and bronchial biopsies of 34 smokers with chronic obstructive pulmonary disease (9 Global initiative for Chronic Obstructive Lung Disease stage 0, 9 stage I, 10 stage II and 6 stage III) and 26 asymptomatic smokers, and its relationship with past and present smoking habits and airway obstruction.

RESULTS

Neutrophil percentage, interleukin-8 and eosinophilic-cationic-protein levels in sputum were higher in chronic obstructive pulmonary disease (stage I-III) than asymptomatic smokers. Inflammatory cell numbers in bronchial biopsies were similar in both groups. Current smoking correlated positively with macrophages: in bronchial biopsies in both groups, and in sputum in chronic obstructive pulmonary disease. Pack-years smoking correlated positively with biopsy macrophages only in chronic obstructive pulmonary disease.

CONCLUSION

Inflammatory effects of current smoking may mask the underlying ongoing inflammatory process pertinent to chronic obstructive pulmonary disease. This may have implications for future studies, which should avoid including mixed populations of smokers and ex-smokers.

The Rationale for Pharmacologic Therapy in Stable Chronic Obstructive Pulmonary Disease

The structural changes in airways and alveoli that characterize chronic obstructive pulmonary disease (COPD) result from an abnormal and persistent inflammatory reaction to inhaled noxious particles or gases, notably tobacco smoke. This remodeling of the lung leads to irreversible airflow obstruction. However, COPD should be viewed by clinicians as a treatable condition, since most patients with COPD have an additional reversible component related to increased bronchomotor tone. The use of bronchodilators, especially anticholinergics and beta2-agonists, results in a reduction in airway smooth muscle tone and airflow resistance; this translates into marked improvement in significant clinical outcomes such as dyspnea, quality of life, and exercise capacity. An increasing amount of evidence supports the idea that long-acting agents have more significant impact in these parameters than the short-acting preparations.

Chronic obstructive pulmonary disease: thin-section CT measurement of airway wall thickness and lung attenuation

PURPOSE

To prospectively evaluate airway wall thickness and lung attenuation at spirometrically gated thin-section computed tomography (CT) in patients with chronic obstructive pulmonary disease (COPD) and to correlate gated CT findings with pulmonary function test (PFT) results.

MATERIALS AND METHODS

The ethical committee approved the study, and all patients gave informed consent. Forty-two consecutive patients with COPD (20 with and 22 without chronic bronchitis [CB]) underwent gated thin-section CT and PFTs on the same day. The percentage wall area (PWA) and the thickness-to-diameter ratio (TDR) for all depicted bronchi that were round and larger than 2 mm in diameter, the mean lung attenuation (MLA), and the pixel index (PI) at -950 HU were determined. The reproducibility of the airway measurements was preliminarily tested by performing a five-trial examination in a patient with COPD and in a control patient. Differences in airway and lung attenuation measurements between the patients with and those without CB were evaluated at Mann-Whitney U testing. Simple and multiple regression analyses were used to assess the correlation between thin-section CT and PFT measurements.

RESULTS

The mean intraoperator coefficient of variation for airway measurements was 7.8% (range, 3.8%-13.4%). An average of nine bronchi per patient were assessed. Patients with CB had significantly higher PWAs, TDRs, and MLAs and significantly lower PIs than patients without CB (P < .05 for all values). The combination of PWA, TDR, and PWA normalized to body weight correlated significantly (P < .05) with the forced expiratory volume in 1 second-to-slow vital capacity ratio and the diffusing capacity of the lung for carbon monoxide in patients with but not in patients without CB. PFT results correlated better with MLA and PI in patients without CB.

CONCLUSION

Bronchial wall measurements differ between patients who have COPD with CB and those who have COPD without CB. The correlation between airway dimensions and indexes of airway obstruction in patients with COPD and CB indicates that the bronchial tree is the site of anatomic-functional alterations in this patient group.

Enhanced bronchial expression of vascular endothelial growth factor and receptors (Flk-1 and Flt-1) in patients with chronic obstructive pulmonary disease

BACKGROUND

Ongoing inflammatory processes resulting in airway and vascular remodelling characterise chronic obstructive pulmonary disease (COPD). Vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 (Flt-1) and VEGFR-2 (KDR/Flk-1) could play a role in tissue remodelling and angiogenesis in COPD.

METHODS

The cellular expression pattern of VEGF, Flt-1, and KDR/Flk-1 was examined by immunohistochemistry in central and peripheral lung tissues obtained from ex-smokers with COPD (forced expiratory volume in 1 second (FEV(1)) <75% predicted; n = 14) or without COPD (FEV(1) >85% predicted; n = 14). The immunohistochemical staining of each molecule was quantified using a visual scoring method with grades ranging from 0 (no) to 3 (intense).

RESULTS

VEGF, Flt-1, and KDR/Flk-1 immunostaining was localised in vascular and airway smooth muscle (VSM and ASM) cells, bronchial, bronchiolar and alveolar epithelium, and macrophages. Pulmonary endothelial cells expressed Flt-1 and KDR/Flk-1 abundantly but not VEGF. Bronchial VEGF expression was higher in microvascular VSM cells and ASM cells of patients with COPD than in patients without COPD (1.7 and 1.6-fold, p<0.01, respectively). VEGF expression in intimal and medial VSM (1.7 and 1.3-fold, p<0.05) of peripheral pulmonary arteries associated with the bronchiolar airways was more intense in COPD, as was VEGF expression in the small pulmonary vessels in the alveolar region (1.5 and 1.7-fold, p<0.02). In patients with COPD, KDR/Flk-1 expression was enhanced in endothelial cells and in intimal and medial VSM (1.3, 1.9 and 1.5-fold, p<0.02) while endothelial Flt-1 expression was 1.7 times higher (p<0.03). VEGF expression was significantly increased in bronchiolar and alveolar epithelium as well as in bronchiolar macrophages (1.5-fold, p<0.001). The expression of VEGF in bronchial VSM and mucosal microvessels as well as bronchiolar epithelium was inversely correlated with FEV(1) (r<-0.45; p<0.01).

CONCLUSIONS

VEGF and its receptors Flt-1 and KDR/Flk-1 may be involved in peripheral vascular and airway remodelling processes in an autocrine and/or paracrine manner. This system may also be associated with epithelial cell viability during airway wall remodelling in COPD.

Increased CD4+ T cell infiltrates in rheumatoid arthritis-associated interstitial pneumonitis compared with idiopathic interstitial pneumonitis

OBJECTIVE

To study lymphocyte markers in rheumatoid arthritis (RA)-associated interstitial pneumonitis (IP) compared with idiopathic IP.

METHODS

Paraffin-embedded lung biopsy specimens from patients with RA (n = 15) and from those without RA (n = 16), all of whom had a diagnosis of either nonspecific IP or usual IP, were studied. Tissue sections from each patient were reviewed by a pathologist, who was blinded to the clinical data. Age and pulmonary function test results were similar in RA and non-RA patients. After high-temperature antigen unmasking, sections were incubated with mouse monoclonal antibodies directed against CD3, CD4, CD8, CD16, and CD20. All slides were coded, and digital images (100x magnification) of the entire tissue area were obtained. Staining was quantified using computer-assisted image analysis.

RESULTS

Staining for CD4 was more prominent in patients with RA than in the non-RA comparison group (median 9.3 cells/mm(2), interquartile range [IQR] 5.5-27.3 versus 0.6 cells/mm(2), IQR 0.2-1.9; P = 0.002). CD4+ cell counts were increased in RA patients with nonspecific IP as well as in RA patients with usual IP, with no major difference between these groups. Results were similar for quantification of CD3 (P = 0.012). There was a less striking trend toward more CD8+ cells in RA patients (P = 0.27 versus those with non-RA lung disease).

CONCLUSION

IP lesions in patients with RA are characterized by an increased number of CD4+ cells, as compared with that in patients with idiopathic IP. This finding suggests that CD4+ T cells are critical for the development of pulmonary manifestations in RA, and may have implications for the treatment of RA-associated lung disease.

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.

Acute exacerbations of chronic bronchitis: new developments concerning microbiology and pathophysiology--impact on approaches to risk stratification and therapy

Exacerbations are a characteristic feature of chronic obstructive pulmonary disease and contribute significantly to associated morbidity and mortality. Renewed interest in this common clinical problem and research using new investigative tools has enhanced substantially the understanding of the pathogenesis of exacerbations. Results of recent clinical trials and observational studies have allowed refinements in treatment of exacerbations that should im-prove patient outcomes. This article discusses a rational, stratified approach to the use of antibiotics for this condition based on these recent studies.

Proteins as biomarkers of oxidative/nitrosative stress in diseases: the contribution of redox proteomics

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) contribute to the pathogenesis and/or progression of several human diseases. Proteins are important molecular signposts of oxidative/nitrosative damage. However, it is generally unresolved whether the presence of oxidatively/nitrosatively modified proteins has a causal role or simply reflects secondary epiphenomena. Only direct identification and characterization of the modified protein(s) in a given pathophysiological condition can decipher the potential roles played by ROS/RNS-induced protein modifications. During the last few years, mass spectrometry (MS)-based technologies have contributed in a significant way to foster a better understanding of disease processes. The study of oxidative/nitrosative modifications, investigated by redox proteomics, is contributing to establish a relationship between pathological hallmarks of disease and protein structural and functional abnormalities. MS-based technologies promise a contribution in a new era of molecular medicine, especially in the discovery of diagnostic biomarkers of oxidative/nitrosative stress, enabling early detection of diseases. Indeed, identification and characterization of oxidatively/nitrosatively modified proteins in human diseases has just begun.

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.

The pathophysiology of airway dysfunction

Asthma and chronic obstructive pulmonary disease (COPD) are distinct inflammatory disorders with differing pathophysiologic mechanisms, different clinical courses, and, therefore, distinct treatment strategies. Whereas in asthma airflow limitation is typically episodic and reversible, airflow limitation in COPD is progressive and only partially reversible. In contrast to asthma, which is characterized by an elevated number of eosinophils in the blood and the accumulation of elevated numbers of activated eosinophils, mast cells, and CD4+ T(H)2-lymphocytes in the lungs, the primary inflammatory cells present in the lungs of patients with stable COPD are neutrophils, macrophages, and CD8+ lymphocytes. Bronchoconstriction in COPD is largely regulated by cholinergically mediated vagal tone, and the pathologic processes of COPD further reduce airway patency. Bronchodilators, most notably anticholinergics, are recommended as first-line pharmacologic therapy for COPD. Proper use of inhaled anticholinergic medications has been shown to lead to significant reversibility of acetylcholine-mediated bronchoconstriction during both stable disease and exacerbations of COPD. For patients with asthma, current guidelines recommend anti-inflammatory medications, specifically inhaled corticosteroids and leukotriene-modifiers, as first-line therapy, making these agents the mainstay of asthma therapy. In contrast, the current guidelines for COPD management recommend that inhaled anti-inflammatory agents be tried in patients with COPD only as second-line therapy for patients who have severe to very severe airflow obstruction with frequent exacerbations and who remain symptomatic despite maximized bronchodilation with multiple inhaled bronchodilators. Hence, it is extremely important to understand the differences between the underlying pathogenesis and pathophysiology of COPD and those of asthma, as these differences dictate the implementation of distinctly different treatment options for these 2 diseases.

The effect of selective phosphodiesterase isoenzyme inhibition on neutrophil function in vitro

Neutrophil-derived proteases such as neutrophil elastase (NE) and matrix metalloproteinase (MMP) are implicated in the pathogenesis of Chronic Obstructive Pulmonary Disease (COPD). In this study, the effects of selective phosphodiesterase (PDE) inhibition on NE and MMP-9 release, as well as Myeloperoxidase (MPO) activity and integrin-mediated neutrophil adhesion to human umbilical vein endothelial cells (HUVECs), were investigated. Human neutrophils were treated with PDE inhibitors (10(-11)-10(-4)M) in the absence and presence of TNF-alpha (tumour necrosis factor) (100 U ml(-1)) for 30 min, prior to fMLP activation. After 45 min, the cells were removed and NE, MPO and MMP-9 release assessed. In the adhesion studies, the neutrophils were radio-labelled with 51Cr, stimulated and immediately transferred to cultured HUVEC monolayers for 30 min, prior to assessment of adhesion. TNF-alpha (100 U ml(-1)) acted synergistically with fMLP in stimulating azurophil degranulation with respect to both MPO activity (P<0.01) and NE release (P<0.01). In contrast, an additive effect was observed with TNF-alpha and fMLP with regard to MMP-9 release and neutrophil adhesion to HUVECs. The PDE4 inhibitors, roflumilast, roflumilast N-oxide, cilomilast and rolipram significantly suppressed MPO, NE and MMP-9 release in both the presence and absence of TNF-alpha (P<0.05; n=6-10) and also reduced neutrophil adhesion to HUVECs. In contrast, milrinone, a PDE3 inhibitor and the non-selective PDE inhibitor, theophylline did not inhibit azurophil degranulation under any of the experimental conditions. These data provide further evidence that selective PDE4 isoenzyme inhibitors can inhibit neutrophil degranulation, effects not shared by PDE3 inhibitors or theophylline.

The novel phosphodiesterase 4 inhibitor, CI-1044, inhibits LPS-induced TNF-alpha production in whole blood from COPD patients

Chronic obstructive pulmonary disease (COPD) is a common, progressive respiratory disease that causes great morbidity and mortality despite treatment. Tumor necrosis factor alpha (TNF-alpha) plays a central role as a pro-inflammatory cytokine in COPD. TNF-alpha release is markedly inhibited by phosphodiesterase type 4 (PDE4) inhibitors that have proven efficacious in COPD clinical trials. The aim of this study was to compare the in vitro activities of the novel selective PDE4 inhibitors CI-1044 compared to well-known PDE4 inhibitors, rolipram and cilomilast, and to the glucocorticoid dexamethasone at reducing lipopolysaccharide (LPS)-induced TNF-alpha release in whole blood from COPD patients and healthy subjects. In the whole blood from COPD patients pre-incubation with PDE4 inhibitors or dexamethasone resulted in a dose-dependent inhibition of LPS-induced TNF-alpha release with IC(50) values of 1.3+/-0.7, 2.8+/-0.9 microM, higher to 10 microM and lesser than 0.03 microM for CI-1044, rolipram, cilomilast and dexamethasone, respectively. We observed a similar inhibition in the whole blood from healthy volunteers with, however, higher IC(50) values. These results indicate that CI-1044 inhibits in vitro LPS-induced TNF-alpha release in whole blood from COPD patients better than rolipram and cilomilast and suggested that it could be a useful anti-inflammatory therapy in COPD.

ACE I allele and eNOS G allele crosstalk may have a role in chronic obstructive pulmonary disease

BACKGROUND

Pulmonary hypertension, a characteristic of chronic obstructive pulmonary disease (COPD) has led us to investigate polymorphisms in angiotensin-converting enzyme (ACE) and endothelial nitric oxide synthase (eNOS) genes.

DESIGN AND METHODS

Sixty-six normal and 27 patients, all of whom were smokers, were screened for ACE Insertion/Deletion (I/D) and eNOS G894T and CA-repeat polymorphisms and for plasma ACE and NO levels.

RESULTS

Elevated ACE and decreased NO levels were obtained with the pattern of II to ID to DD and GG to GT to TT conversion, respectively. Furthermore, the genotype combination of II and GG was significantly greater in controls as compared to patients (P = 0.01; OR = 2.43; 95% CI: 1.21-4.87; RR = 2.00, 1.15-3.48). The CA-repeat multialleles showed a trimodal pattern in both the groups with a frequency range of 0.0057-0.103 and 0.0208-0.1875 in the controls and patients, respectively.

CONCLUSIONS

The lower ACE and higher NO levels by virtue of the interchromosomal interaction between the I and G alleles appear to cause less vasoconstriction and increase vasodilatation that may be advantageous in the improvement of the disease.

Inhaled corticosteroids in chronic obstructive pulmonary disease: is there a long-term benefit?

PURPOSE OF REVIEW

The use of inhaled corticosteroids is one of the most controversial issues in COPD pharmacotherapy. Experts disagree about the benefits and harms of ICS for patients with COPD, yet a majority of patients with COPD are being treated with inhaled corticosteroids. This is a review of the most recent literature on this subject.

RECENT FINDINGS

Evidence suggests that ICS, with or without a long-acting beta2-agonist, are cost-effective in reducing exacerbation rates and retarding the decline in health status of COPD patients, although they do not significantly modify the rate of decline in FEV1 or change mortality. This discrepancy is likely related to the differences in pathology of COPD when compared with asthma. Evidence also suggests that ICS may be safe regarding the effects on adrenals and bone mineral density. We have yet to identify reliable criteria for predicting a response to ICS in COPD, but it has become clear that in mild disease, no beneficial effect has been demonstrated.

SUMMARY

In contrast to asthma, inhaled corticosteroids should not be used as a first-line medication in patients with COPD. Identification of patients with COPD who might benefit from long-term treatment with ICS remains paramount.

Prospects for new drugs for chronic obstructive pulmonary disease

No currently available treatments have been shown to slow the progression of chronic obstructive pulmonary disease (COPD) or suppress the inflammation in small airways and lung parenchyma. However, several new treatments are in clinical development; some target the inflammatory process and others are directed against structural cells. A group of specific therapies are directed against the influx of inflammatory cells into the airways and lung parenchyma that occurs in COPD; these include agents directed against adhesion molecules and chemokines, as well as therapies to oppose tumour necrosis factor alpha and increase interleukin 10. Broad-range anti-inflammatory drugs are now in phase III development for COPD; they include inhibitors of phosphodiesterase 4. Other drugs that inhibit cell signalling include inhibitors of p38 mitogen-activated protein kinase, nuclear factor kappaB, and phosphoinositide-3-kinase gamma. More specific approaches are to give antioxidants, inhibitors of inducible nitric oxide synthase, and antagonists of leukotriene B4 receptor. Inhibitors of epidermal-growth-factor-receptor kinase and calcium-activated chloride channels have the potential to prevent overproduction of mucus. Therapy to inhibit fibrosis is being developed against transforming growth factor beta1 and protease-activated receptor 2. There is also a search for inhibitors of serine proteinases and matrix metalloproteinases to prevent lung destruction and the development of emphysema, as well as drugs such as retinoids that might even reverse this process. Effective delivery of drugs to the sites of disease in the peripheral lung is an important consideration, and there is a need for validated biomarkers and monitoring techniques in early clinical studies with new therapies for COPD.

Characterization of mainstream cigarette smoke-induced biomarker responses in ICR and C57Bl/6 mice

Pulmonary emphysema is a major component of the morbidity and mortality of chronic obstructive pulmonary disease (COPD). Currently there are no predictive biomarkers for COPD. Initial steps toward identifying potentially predictive biomarkers involve utilizing well-characterized mainstream smoke (MS) exposure conditions (dose-response) to identify changes in biomarkers of effect (inflammation, tissue injury, oxidative stress) in emphysema-susceptible and -resistant mouse strains. C57Bl/6 mice have been reported to develop emphysema when exposed chronically to cigarette smoke, while similarly exposed ICR mice do not. Male C57Bl/6 and ICR mice were exposed 2 h/day for 7 consecutive days to MS from a standard reference cigarette (2R4F) at 75, 250, and 600 microg total particulate matter (TPM)/L or filtered air. To confirm exposure, blood samples were collected toward the end of the last exposure and analyzed for carboxyhemoglobin, nicotine, and cotinine. Bronchoalveolar lavage (BAL) fluid samples were collected 2 or 12 h postexposure and analyzed for biomarkers of effect. MS dose differed slightly between strains. More necrosis was observed in nasal epithelium of exposed C57Bl/6 mice. Exposure concentration-dependent increases in apoptosis, chemokines, and neutrophil counts were greater in ICR mice. Similar increases in thymus and activated-regulated chemokine were only observed in C57Bl/6 mice. BAL fluid cells of C57Bl/6 mice appear to undergo necrosis, while the BAL fluid cells of ICR mice appear to undergo apoptosis following MS exposure. Utilizing two strains of mice we identified MS-responsive biomarkers of effect that may be predictive of COPD pathology. Chronic MS exposures are needed to link these biomarkers with emphysema.

Theophylline restores histone deacetylase activity and steroid responses in COPD macrophages

Chronic obstructive pulmonary disease (COPD) is a common chronic inflammatory disease of the lungs with little or no response to glucocorticoids and a high level of oxidative stress. Histone deacetylase (HDAC) activity is reduced in cells of cigarette smokers, and low concentrations of theophylline can increase HDAC activity. We measured the effect of theophylline on HDAC activity and inflammatory gene expression in alveolar macrophages (AM) from patients with COPD. AM from normal smokers showed a decrease in HDAC activity compared with normal control subjects, and this was further reduced in COPD patients (51% decrease, P < 0.01). COPD AMs also showed increased basal release of IL-8 and TNF-α, which was poorly suppressed by dexamethasone. Theophylline induced a sixfold increase in HDAC activity in COPD AM lysates and significantly enhanced dexamethasone suppression of induced IL-8 release, an effect that was blocked by the HDAC inhibitor trichostatin A. Therefore, theophylline might restore steroid responsiveness in COPD patients.

Kinase targets and inhibitors for the treatment of airway inflammatory diseases: the next generation of drugs for severe asthma and COPD?

Kinases are believed to play a crucial role in the expression and activation of inflammatory mediators in the airway, in T-cell function, and in airway remodeling. Important pro-inflammatory transcription factors such as activating protein-1 and nuclear factor kappaB, which are activated in airway disease, require kinase activation to switch on inflammatory genes, while other kinases can regulate mRNA half-life. Selective kinase inhibitors have been developed that reduce inflammatory gene expression and some characteristics of disease in animal models. Targeting specific kinases that are overexpressed or overactive in disease should allow for selective treatment of airway inflammatory diseases. Interest in this area has intensified due to the success of the specific Abelson murine leukemia viral oncogene homolog tyrosine kinase inhibitor, imatinib mesylate, in the treatment of chronic myelogenous leukemia. Encouraging data from animal models and primary cells and early phase I and II studies in other diseases suggest that inhibitors of p38 mitogen-activated protein kinase and inhibitor of kappaB kinase-2 may prove to be useful novel therapies in the treatment of severe asthma and chronic obstructive pulmonary disease.

Inhaled Combination Therapy With Long-Acting β 2 -Agonists and Corticosteroids in Stable COPD

Long-acting beta(2)-agonists (LABAs) have been shown to be effective first-line bronchodilators in the treatment of COPD patients, and inhaled corticosteroids (ICSs) have been shown to reduce the frequency and/or severity of exacerbations in COPD patients. The concomitant use of a LABA and an ICS can influence both airway obstruction (ie, smooth muscle contraction, increased cholinergic tone, and loss of elastic recoil), and airway inflammation (ie, increased numbers of neutrophils, macrophages, and CD8+ lymphocytes, elevated interleukin-8 and tumor necrosis factor-alpha levels, and protease/antiprotease imbalance). They are also able to reduce the total number of bacteria adhering to the respiratory mucosa in a concentration-dependent manner without altering the bacterial tropism for mucosa, and to preserve ciliated cells. Several clinical trials support the concept of inhaled combination therapy with LABAs and corticosteroids in stable COPD patients. This type of therapy not only improves airflow obstruction but also provides clinical benefits, as manifested by sustained reduction in overall symptoms, improvements in health-related quality of life, and reductions in exacerbations. All of these effects are very important because, despite recent advances in our understanding of COPD and its treatment, therapy remains suboptimal for a considerable number of patients.

PDE4 inhibitors in COPD—a more selective approach to treatment

Chronic obstructive pulmonary disease (COPD) is a serious and mounting global public health problem. Although its pathogenesis is incompletely understood, chronic inflammation plays an important part and so new therapies with a novel anti-inflammatory mechanism of action may be of benefit in the treatment of COPD. Cilomilast and roflumilast are potent and selective phosphodiesterase (PDE)4 inhibitors, with an improved therapeutic index compared with the weak, non-selective PDE inhibitor, theophylline. Unlike theophylline, which is limited by poor efficacy and an unfavourable safety and tolerability profile, the selective PDE4 inhibitors are generally well tolerated, with demonstrated efficacy in improving lung function, decreasing the rate of exacerbations and improving quality of life, with proven anti-inflammatory effects in patients with COPD. Theophylline is a difficult drug to use clinically, requiring careful titration and routine plasma monitoring due to the risk of toxic side effects, such as cardiovascular and central nervous system adverse events, with dose adjustments required in many patients, including smokers, the elderly and some patients on concomitant medications. In contrast, the selective PDE4 inhibitors are convenient medications for both patient and physician alike. Hence these agents represent a therapeutic advance in the treatment of COPD, due to their novel mechanism of action and potent anti-inflammatory effects, coupled with a good safety and tolerability profile.

Dissociation of lung function and airway inflammation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is defined by progressive, irreversible airflow limitation and an inflammatory response of the lungs, usually to cigarette smoke. However, COPD is a heterogeneous disease in terms of clinical, physiologic, and pathologic presentation. We aimed to evaluate whether airflow limitation, airway responsiveness, and airway inflammation are separate entities underlying the pathophysiology of COPD by using factor analysis. A total of 114 patients (99 males/15 females, age 62 +/- 8 years, 42 pack-years smoking, no inhaled or oral steroids > 6 months) with irreversible airflow limitation (postbronchodilator FEV(1) 63 +/- 9% predicted, FEV(1)/inspiratory vital capacity [IVC] 48 +/- 9%) and symptoms of chronic bronchitis or dyspnea were studied in a cross-sectional design. Postbronchodilator FEV(1) and FEV(1)/IVC, reversibility to inhaled beta(2)-agonists, diffusing capacity, provocative concentration of methacholine required to produce a 20% drop in FEV(1), total serum IgE, exhaled nitric oxide, and induced sputum cell counts (% eosinophils, % neutrophils) were collected. Factor analysis yielded 4 separate factors that accounted for 63.6% of the total variance. Factor 1 was comprised of FEV(1), FEV(1)/IVC, and residual volume/total lung capacity. Factor 2 included reversibility, IgE, provocative concentration of methacholine required to produce a 20% drop in FEV(1,) and diffusing capacity. Factor 3 contained exhaled nitric oxide and factor 4 included sputum % neutrophils and % eosinophils. We conclude that airflow limitation, airway inflammation, and features commonly associated with asthma are separate and largely independent factors in the pathophysiology of COPD.

Macrophage phagocytosis of apoptotic neutrophils is compromised by matrix proteins modified by cigarette smoke and lipid peroxidation products

Clearance of apoptotic cells by phagocytosis plays an important role in the resolution of an inflammatory response. Macrophages interacting with extracellular matrix (ECM) proteins upregulate their phagocytic capacity. Cigarette smoke contains highly reactive carbonyls that modify proteins which directly/indirectly affects cellular function. We observed, in vitro, that human macrophages interacting with carbonyl or cigarette smoke modified ECM proteins dramatically down regulated their ability to phagocytose apoptotic neutrophils. We also show that this interaction with carbonyl-adduct modified ECM proteins led to increased macrophage adhesion in vitro. We hypothesise that changes in the ECM environment as a result of cigarette smoking affect the ability of macrophages to remove apoptotic cells. Moreover, we postulate that this decreased phagocytic activity was as a result of sequestration of receptors involved in the uptake of apoptotic cells towards that of recognition of carbonyl adducts on the modified ECM proteins leading to increased macrophage adhesion.

Activation of Bronchial Epithelial Cells in Smokers Without Airway Obstruction and Patients With COPD

STUDY OBJECTIVE

The aim of this study was to investigate the basal level as well as the tumor necrosis factor (TNF)-alpha- and interferon (IFN)-gamma-induced expression and release of the neutrophil chemoattractants interleukin (IL)-8 and growth-related oncogene (GRO)-alpha in primary bronchial epithelial cells (PBECs) from smokers without airflow obstruction and patients with COPD. In addition, the expression of both TNF-alpha-receptor subtypes--p55 TNF-receptor subtype (TNF-R55) and p75 TNF-receptor subtype (TNF-R75)--was quantified in PBECs.

DESIGN

PBECs from eight smokers without airflow limitation and eight patients with COPD were stimulated with 50 ng/mL of TNF and 200 U/mL of IFN-gamma for 4 h along with unstimulated time controls. The transcriptional expression and protein release were quantitatively assessed by means of real-time polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

Basal level messenger RNA (mRNA) expression and protein release of IL-8 and GRO-alpha were not significantly different between both groups, although a trend toward higher IL-8 levels was seen in patients with COPD. TNF-alpha induced significantly higher mRNA amounts of IL-8 (p = 0.005) and GRO-alpha (p = 0.007) in patients with COPD. This was accompanied by higher protein release data for IL-8 (p = 0.005) and GRO-alpha (p = 0.007). IFN-gamma had no significant effect on the mRNA expression and protein release of IL-8 and GRO-alpha in either group. TNF-R55 and TNF-R75 were detectable in PBECs. However, no significant differences were found between both groups with respect to steady-state mRNA levels of TNF-alpha-receptor subtypes.

CONCLUSION

PBECs from patients with COPD show significantly higher TNF-alpha-induced release of the neutrophil chemoattractant CXC-chemokines IL-8 and GRO-alpha compared to smokers without airflow limitation. This increased activation of PBECs may contribute to the predominance of neutrophils seen in the airway lumen of patients with COPD.

Dysregulation of IL-2 and IL-8 production in circulating T lymphocytes from young cystic fibrosis patients

It is well documented that patients with cystic fibrosis (CF) are unable to clear persistent airway infections in spite of strong local inflammation, suggesting a dysregulation of immunity in CF. We and others have reported previously that T lymphocytes may play a prominent role in this immune imbalance. In the present work, we compared the reactivity of CD3+ T cells obtained from young CF patients in stable clinical conditions (n = 10, aged 9-16.5 years) to age-matched healthy subjects (n = 6, aged 9-13.5 years). Intracellular levels of interferon (IFN)-gamma, interleukin (IL)-2, IL-8 and IL-10 were determined by flow cytometry after whole blood culture. The data identified T lymphocyte subsets producing either low levels (M1) or high levels (M2) of cytokine under steady-state conditions. We found that the production of IFN-gamma and IL-10 by T lymphocytes was similar between young CF patients and healthy subjects. In contrast, after 4 h of activation with PMA and ionomycin, the percentage of T cells producing high levels of IL-2 (M2) was greater in CF patients (P = 0.02). Moreover, T cells from CF patients produced lower levels of IL-8, before and after activation (P = 0.007). We conclude that a systemic immune imbalance is present in young CF patients, even when clinically stable. This disorder is characterized by the capability of circulating T lymphocytes to produce low levels of IL-8 and by the emergence of more numerous T cells producing high levels of IL-2. This imbalance may contribute to immune dysregulation in CF.