Sputum eosinophilia and the short term response to inhaled mometasone in chronic obstructive pulmonary disease

Aspects on pathophysiological mechanisms in COPD

Chronic obstructive pulmonary disease (COPD) is a condition which is characterized by irreversible airway obstruction due to narrowing of small airways, bronchiolitis, and destruction of the lung parenchyma, emphysema. It is the fourth most common cause of mortality in the world and is expected to be the third most common cause of death by 2020. The main cause of COPD is smoking but other exposures may be of importance. Exposure leads to airway inflammation in which a variety of cells are involved. Besides neutrophil granulocytes, macrophages and lymphocytes, airway epithelial cells are also of particular importance in the inflammatory process and in the development of emphysema. Cell trafficking orchestrated by chemokines and other chamoattractants, the proteinase-antiproteinase system, oxidative stress and airway remodelling are central processes associated with the development of COPD. Recently systemic effects of COPD have attracted attention and the importance of systemic inflammation has been recognized. This seems to have direct therapeutic implications as treatment with inhaled glucocorticosteroids has been shown to influence mortality. The increasing body of knowledge regarding the inflammatory mechanism in COPD will most likely have implications for future therapy and new drugs, specifically aimed at interaction with the inflammatory processes, are currently being developed.

Airways disease: phenotyping heterogeneity using measures of airway inflammation

: Despite asthma and chronic obstructive pulmonary disease being widely regarded as heterogeneous diseases, a consensus for an accurate system of classification has not been agreed. Recent studies have suggested that the recognition of subphenotypes of airway disease based on the pattern of airway inflammation may be particularly useful in increasing our understanding of the disease. The use of non-invasive markers of airway inflammation has suggested the presence of four distinct phenotypes: eosinophilic, neutrophilic, mixed inflammatory and paucigranulocytic asthma. Recent studies suggest that these subgroups may differ in their etiology, immunopathology and response to treatment. Importantly, novel treatment approaches targeted at specific patterns of airway inflammation are emerging, making an appreciation of subphenotypes particularly relevant. New developments in phenotyping inflammation and other facets of airway disease mean that we are entering an era where careful phenotyping will lead to targeted therapy.

Inhaled corticosteroids for stable chronic obstructive pulmonary disease

BACKGROUND

The role of inhaled corticosteroids (ICS) in chronic obstructive pulmonary disease (COPD) has been the subject of much controversy. Major international guidelines recommend selective use of ICS. Recently published meta-analyses have reported conflicting findings on the effects of inhaled steroid therapy in COPD.

OBJECTIVES

The objective of the review is to determine the efficacy of regular use of inhaled corticosteroids in patients with stable COPD.

SEARCH STRATEGY

A pre-defined search strategy was used to search the Cochrane Airways Group specialised register for relevant literature. Searches are current as of October 2006.

SELECTION CRITERIA

We selected randomised trials comparing any dose of any type of inhaled steroid with a placebo control in patients with COPD. Acute bronchodilator reversibility to short term beta2-agonists and bronchial hyperresponsiveness were not exclusion criteria. The a priori primary outcome was change in lung function. Data on mortality, exacerbations, quality of life and symptoms, rescue bronchodilator use, exercise capacity, biomarkers and safety were also analysed.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

Forty-seven primary studies with 13,139 participants met the inclusion criteria. Medium term use of ICS (> two months and up to six months) resulted in a small improvement in FEV1 in some studies. Long term use of ICS (> six months) did not significantly reduce the rate of decline in FEV1 in COPD patients (weighted mean difference (WMD) 5.80 ml/year with ICS over placebo, 95% CI -0.28 to 11.88, 2333 participants). There was no statistically significant effect on mortality in COPD patients (OR 0.98, 95% CI 0.83 to 1.16, 8390 participants). Long term use of ICS reduced the mean rate of exacerbations in those studies where pooling of data was possible (WMD -0.26 exacerbations per patient per year, 95% CI -0.37 to -0.14, 2586 participants). ICS slowed the rate of decline in quality of life, as measured by the St George's Respiratory Questionnaire (WMD -1.22 units/year, 95% CI -1.83 to -0.60, 2507 participants). Response to ICS was not predicted by oral steroid response, bronchodilator reversibility or bronchial hyper-responsiveness in COPD patients. There was an increased risk of oropharyngeal candidiasis (OR 2.49, 95% CI 1.78 to 3.49, 4380 participants) and hoarseness. The few long term studies that measured bone effects generally showed no major effect on fractures and bone mineral density over 3 years.

AUTHORS' CONCLUSIONS

Patients and clinicians should balance the potential benefits of inhaled steroids in COPD (reduced rate of exacerbations, reduced rate of decline in quality of life), against the known increase in local side effects (oropharyngeal candidiasis and hoarseness). The risk of long term adverse effects is unknown.

Quantitative sputum cell counts as a marker of airway inflammation in clinical practice

PURPOSE OF REVIEW

Bronchitis, meaning airway inflammation, is an important component of airway disease. Yet respirologists and allergists, who have stressed the importance of measurements of airway function, have been slow to introduce airway inflammation measurements into clinical practice. Of the measurements available, quantitative sputum cell counts have the most clinical value. This article provides additional information on this topic from studies published in 2005 and 2006.

RECENT FINDINGS

Airway diseases are heterogeneous within patients in terms of the disease present and the type of airway inflammation. Quantitative sputum cell counts (total cell count as well as the differential) identify noneosinophilic, mainly neutrophilic, probably infective exacerbations as common in patients with asthma and chronic obstructive pulmonary disease that may be unresponsive to corticosteroid treatment. In contrast, measurements of sputum eosinophils can be used to guide the minimum dose of corticosteroid required to control eosinophilic bronchitis and reduce eosinophilic exacerbations.

SUMMARY

Measurements of quantitative sputum cell counts need to be made available, initially by tertiary care centres, to diagnose bronchitis in airway disease and to optimize treatment. Examination of how these are complemented by indirect measures of airway inflammation, specifically exhaled nitric oxide and airway hyperresponsiveness to stimuli acting indirectly through mediator release, requires further investigation.

Future therapeutic treatment of COPD: struggle between oxidants and cytokines

Chronic obstructive pulmonary disease (COPD) is a global health problem. Being a progressive disease characterized by inflammation and predominantly caused by tobacco smoking, it deteriorates pulmonary and skeletal muscle functioning, and reduces physical behavior, societal participation and quality of life. During the last two decades studies were focused on the airway and systemic inflammation, oxidative stress, and airway and/or parenchymal remodeling. Macrophages, neutrophils and T cells are thought to be important key players, as well as structural cells like fibroblasts, epithelial, endothelial and smooth muscle cells. Mediators and proteins including cytokines, chemokines, growth factors, proteinases, and oxidants seem to be involved differentially in its pathogenesis. Current pharmacological treatments are directed to reducing airway inflammation, boosting the endogenous levels of anti-oxidants and relieving airway contraction and sputum production. Most agents were primarily used for treating asthma. But in contrast to asthma, these treatments are not very effective in COPD. As a result, novel more specifically acting interventional drugs with less side effects are being developed to treat chronic inflammatory diseases, including COPD. This review highlights studies on novel or potential drug antioxidants such as dietary antioxidants supplementation, N-acetyl-L-cysteine, N-acystelyn, endosteine, antioxidant enzyme mimetics, and anti-inflammatory agents like antagonists of cytokines, such as tumor necrosis factor (TNF)-alpha, CXCL8, and CCL2, and inhibitors of signal transduction proteins including phosphodiesterase 4, MAPK p38, P1-3k, and NFkappaB.

Clinical applications of induced sputum

The development of standardized methods for sputum induction has improved the quality and reproducibility of sputum samples. This technique has been used to optimize samples in the investigation of pulmonary tuberculosis and lung cancer, but its clinical application as a noninvasive measure of airway inflammation has highlighted the enormous potential of this technique. Sputum induction has allowed researchers to characterize the inflammatory profiles of a variety of airway diseases including asthma, COPD, and chronic cough. To date, the identification of sputum eosinophilia has the greatest clinical value as this predicts a favorable response to corticosteroids and can therefore guide treatment. In asthma and COPD management, protocols aimed at normalizing the sputum eosinophil count have markedly reduced exacerbations without an overall increase in therapy. Currently, no other noninvasive measure of airway inflammation has demonstrated a benefit in reducing exacerbations. The value of sputum induction and analysis is not restricted to the recognition of sputum eosinophilia but also may be used to direct novel antineutrophilic therapies. Thus, it is time for sputum induction to move from the research laboratory to the clinic.

Inflammatory cells in the airways in COPD

Airway inflammation is central to the pathogenesis of both airway remodelling and parenchymal destruction in chronic obstructive pulmonary disease (COPD). Neutrophils, macrophages, and CD8+ T lymphocytes have been implicated in a number of studies, but a detailed profile of disease-phenotype specific inflammation has yet to emerge. The heterogeneity of the disease has hindered data interpretation while extrapolation of the results of relatively non-invasive studies to the actual pathology found in the distal lung is difficult. Moreover, prominent studies have had frequently conflicting results. Further investigations are needed to marry the different clinical phenotypes of COPD to their respective inflammatory profiles in the airways and thus improve our understanding of the pathogenesis of the disease as a whole.

Novel insights into the aetiology and pathophysiology of increased airway inflammation during COPD exacerbations

Airway inflammation increases during acute exacerbations of COPD. Extrinsic factors, such as airway infections, increased air pollution, and intrinsic factors, such as increased oxidative stress and altered immunity may contribute to this increase. The evidence for this and the potential mechanisms by which various aetiological agents increase inflammation during COPD exacerbations is reviewed. The pathophysiologic consequences of increased airway inflammation during COPD exacerbations are also discussed. This review aims to establish a cause and effect relationship between etiological factors of increased airway inflammation and COPD exacerbations based on recently published data. Although it can be speculated that reducing inflammation may prevent and/or treat COPD exacerbations, the existing anti-inflammatory treatments are modestly effective.

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.

Antiinflammatory effects of salmeterol/fluticasone propionate in chronic obstructive lung disease

RATIONALE

No currently available treatment is reported to reduce the exaggerated airway wall inflammation of chronic obstructive pulmonary disease.

OBJECTIVES

We tested the hypothesis that inhaled combined long-acting beta2-agonist (salmeterol) and corticosteroid (fluticasone propionate) will reduce inflammation.

METHODS

Bronchial biopsies and induced sputum were taken from 140 current and former smokers (mean age, 64 yr) with moderate to severe disease, randomized in a 13-wk double-blind study to placebo (n = 73) or salmeterol/fluticasone propionate 50/500 microg (n = 67) twice daily. Biopsies were repeated at 12 wk and sputa at 8 and 13 wk. After adjustment for multiplicity, comparisons between active and placebo were made for median change from baseline in the numbers of biopsy CD8+ and CD68+ cells/mm2 and sputum neutrophils.

MEASUREMENTS AND MAIN RESULTS

Combination therapy was associated with a reduction in biopsy CD8+ cells of -118 cells/mm2 (95% confidence interval [CI], -209 to -42; p = 0.02), a reduction of 36% over placebo (p = 0.001). CD68+ cells were unaffected by combination treatment. Sputum differential (but not total) neutrophils reduced progressively and, at Week 13, significantly with combination treatment (median treatment difference, 8.5%; 95% CI, 1.75%-15.25%; p = 0.04). The combination also significantly reduced biopsy CD45+ and CD4+ cells and cells expressing genes for tumor necrosis factor-alpha and IFN-gamma and sputum total eosinophils (all p < or = 0.03). These antiinflammatory effects were accompanied by a 173-ml (95% CI, 104-242; p < 0.001) improvement in prebronchodilator FEV1.

CONCLUSIONS

The combination of salmeterol and fluticasone propionate has a broad spectrum of antiinflammatory effects in both current and former smokers with chronic obstructive pulmonary disease, which may contribute to clinical efficacy.