Induced sputum in the investigation of airway inflammation of COPD

Small airways in asthma: From inflammation and pathophysiology to treatment response

Small airways are characterized as those with an inner diameter less than 2 mm and constitute a major site of pathology and inflammation in asthma disease. It is estimated that small airways dysfunction may occur before the emergence of noticeable symptoms, spirometric abnormalities and imaging findings, thus characterizing them as "the quiet or silent zone" of the lungs. Despite their importance, measuring and quantifying small airways dysfunction presents a considerable challenge due to their inaccessibility in usual functional measurements, primarily due to their size and peripheral localization. Several pulmonary function tests have been proposed for the assessment of the small airways, including impulse oscillometry, nitrogen washout, body plethysmography, as well as imaging methods. Nevertheless, none of these methods has been established as the definitive "gold standard," thus, a combination of them should be used for an effective assessment of the small airways. Widely used asthma treatments seem to also affect several parameters of the small airways. Emerging biologic treatments show promising results in reducing small airways inflammation and remodelling, providing evidence for potential alterations in the disease's progression and outcomes. These novel therapies have implications not only in the clinical aspects of asthma but also in its inflammatory and functional aspects.

Pulmonary inflammation promoted by type-2 dendritic cells is a feature of human and murine schistosomiasis

Schistosomiasis is a parasitic disease affecting over 200 million people in multiple organs, including the lungs. Despite this, there is little understanding of pulmonary immune responses during schistosomiasis. Here, we show type-2 dominated lung immune responses in both patent (egg producing) and pre-patent (larval lung migration) murine Schistosoma mansoni (S. mansoni) infection. Human pre-patent S. mansoni infection pulmonary (sputum) samples revealed a mixed type-1/type-2 inflammatory cytokine profile, whilst a case-control study showed no significant pulmonary cytokine changes in endemic patent infection. However, schistosomiasis induced expansion of pulmonary type-2 conventional dendritic cells (cDC2s) in human and murine hosts, at both infection stages. Further, cDC2s were required for type-2 pulmonary inflammation in murine pre-patent or patent infection. These data elevate our fundamental understanding of pulmonary immune responses during schistosomiasis, which may be important for future vaccine design, as well as for understanding links between schistosomiasis and other lung diseases.

Sputum Microbiome and Chronic Obstructive Pulmonary Disease in a Rural Ugandan Cohort of Well-Controlled HIV Infection

Sub-Saharan Africa has increased morbidity and mortality related to chronic obstructive pulmonary disease (COPD). COPD among people living with HIV (PLWH) has not been well studied in this region, where HIV/AIDS is endemic. Increasing evidence suggests that respiratory microbial composition plays a role in COPD severity. Therefore, we aimed to investigate microbiome patterns and associations among PLWH with COPD in Sub-Saharan Africa. We conducted a cross-sectional study of 200 adults stratified by HIV and COPD in rural Uganda. Induced sputum samples were collected as an easy-to-obtain proxy for the lower respiratory tract microbiota. We performed 16S rRNA gene sequencing and used PICRUSt2 (version 2.2.3) to infer the functional profiles of the microbial community. We used a statistical tool to detect changes in specific taxa that searches and adjusts for confounding factors such as antiretroviral therapy (ART), age, sex, and other participant characteristics. We could cluster the microbial community into three community types whose distribution was shown to be significantly impacted by HIV. Some genera, e.g., Veillonella, Actinomyces, Atopobium, and Filifactor, were significantly enriched in HIV-infected individuals, while the COPD status was significantly associated with Gammaproteobacteria and Selenomonas abundance. Furthermore, reduced bacterial richness and significant enrichment in Campylobacter were associated with HIV-COPD comorbidity. Functional prediction using PICRUSt2 revealed a significant depletion in glutamate degradation capacity pathways in HIV-positive patients. A comparison of our findings with an HIV cohort from the United Kingdom revealed significant differences in the sputum microbiome composition, irrespective of viral suppression. IMPORTANCE Even with ART available, HIV-infected individuals are at high risk of suffering comorbidities, as shown by the high prevalence of noninfectious lung diseases in the HIV population. Recent studies have suggested a role for the respiratory microbiota in driving chronic lung inflammation. The respiratory microbiota was significantly altered among PLWH, with disease persisting up to 3 years post-ART initiation and HIV suppression. The community structure and diversity of the sputum microbiota in COPD are associated with disease severity and clinical outcomes, both in stable COPD and during exacerbations. Therefore, a better understanding of the sputum microbiome among PLWH could improve COPD prognostic and risk stratification strategies. In this study, we observed that in a virologically suppressed HIV cohort in rural Uganda, we could show differences in sputum microbiota stratified by HIV and COPD, reduced bacterial richness, and significant enrichment in Campylobacter associated with HIV-COPD comorbidity.

Bacterial Species and Inflammatory Cell Variability in Respiratory Tracts of Patients with Chronic Obstructive Pulmonary Disease Exacerbation: A Multicentric Study

Background and Aim

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) has profound effects on disease progression and patients' quality of life. Emerging evidence suggests an association between alterations in the respiratory microbiome flora species and airway inflammation in patients with AECOPD. The present study aimed to describe the inflammatory cells and bacterial microbiome distributions in respiratory tract in Egyptian patients with AECOPD.

Subjects and Methods

The present cross-sectional study included 208 patients with AECOPD. Sputum and broncho-alveolar lavage samples from the studied patients were submitted to microbial cultures using appropriate media. Total and differential leukocytic counts and were done via automated cell counter.

Results

The present study included 208 AECOPD patients. They comprised 167 males (80.3%) and 41 females (19.7%) with an age of 57.9 ± 4.9 years. AECOPD was categorized as mild, moderate and severe in 30.8%, 43.3% and 26%, respectively. Sputum samples had significantly higher TLC, neutrophil percent and eosinophil percent when compared with BAL samples. In contrast, lymphocyte percent was significantly higher in BAL samples. Sputum specimens had significantly lower frequency of positive growths (70.2% versus 86.5%, p = 0.001). Among the identified organisms, sputum specimens had significantly lower frequency of Strept. pneumoniae (14.4% versus 30.3%, p = 0.001), Klebsiella pneumoniae (19.7% versus 31.7%, p = 0.024), Haemophilus influenzae (12.5% versus 26.9%, p = 0.011), Pseudomonas aeruginosa (2.9% versus 10%, p = 0.019) and Acinetobacter spp. (1.9% versus 7.2%, p = 0.012) growths when compared with BAL samples.

Conclusion

The present study could identify a distinctive pattern of inflammatory cell distribution in sputum and BAL samples of AECOPD patients. The most commonly isolated organisms were Klebsiella pneumoniae and Strept. pneumoniae.

The effect of BCG vaccination on alveolar macrophages obtained from induced sputum from healthy volunteers

The anti-tuberculosis vaccine Bacillus Calmette-Guérin (BCG) is able to boost innate immune responses through a process called 'trained immunity'. It is hypothesized that BCG-induced trained immunity contributes to protection against Mycobacterium tuberculosis infection. Since alveolar macrophages are the first cell type to encounter M. tuberculosis upon infection, we aimed to investigate the immunomodulatory effects of BCG vaccination on alveolar macrophages. Searching for a less-invasive method than bronchoalveolar lavage, we optimized the isolation of alveolar macrophages from induced sputum of healthy volunteers. Viable alveolar macrophages could be successfully isolated from induced sputum and showed signs of activation already upon retrieval. Further flow cytometric analyses revealed that at baseline, higher expression levels of activation markers were observed on the alveolar macrophages of smokers compared to non-smokers. In addition, BCG vaccination resulted in decreased expression of the activation markers CD11b and HLA-DR on alveolar macrophages. Future studies should evaluate the functional consequences of this reduced activation of alveolar macrophages after BCG vaccination.

Mucus Hydration in Subjects with Stable Chronic Bronchitis: A Comparison of Spontaneous and Induced Sputum

Mucus hydration is important in mucus clearance and lung health. This study sought to test the relative utility of spontaneous sputum (SS) versus the reasonably noninvasive induced sputum (IS) samples for measurement of mucus hydration. SS and IS samples were collected over a 2-day study interval. Sputum was induced with escalating inhaled nebulized 3-5% hypertonic saline. Viscous portions of the samples ("plugs") were utilized for percent solids and total mucin analyses. Cytokines, nucleotides/nucleosides and cell differentials were measured in plugs diluted into 0.1% Sputolysin. Overall, 61.5% of chronic bronchitis (CB) subjects produced a SS sample and 95.2% an IS sample. Total expectorate sample weights were less for the SS (0.94 ± 0.98 g) than the IS (2.67 ± 2.33 g) samples. Percent solids for the SS samples (3.56% ± 1.95; n = 162) were significantly greater than the IS samples (3.08% ± 1.81; n = 121), p = 0.133. Total mucin concentrations also exhibited a dilution of the IS samples: SS = 4.15 ± 3.23 mg/ml (n = 62) versus IS= 3.34 ± 2.55 mg/ml (n = 71) (p = 0.371). Total mucins (combined SS and IS) but not percent solids, were inversely associated with FEV₁ percent predicted (p = 0.052) and FEV₁,/FVC % (p = 0.035). There were no significant differences between sample types in cytokine or differential cell counts. The probability of sample collections was less for SS than IS samples. Measurements of hydration revealed modest dilution of the IS samples compared to SS. Thus for measurements of mucus hydration, both SS and IS samples appear to be largely interchangeable.

Review of biomarkers to assess the effects of switching from cigarettes to modified risk tobacco products

Context: One approach to reducing the harm caused by cigarette smoking, at both individual and population level, is to develop, assess and commercialize modified risk alternatives that adult smokers can switch to. Studies to demonstrate the exposure and risk reduction potential of such products generally involve the measuring of biomarkers, of both exposure and effect, sampled in various biological matrices.Objective: In this review, we detail the pros and cons for using several biomarkers as indicators of effects of changing from conventional cigarettes to modified risk products.Materials and methods: English language publications between 2008 and 2017 were retrieved from PubMed using the same search criteria for each of the 25 assessed biomarkers. Nine exclusion criteria were applied to exclude non-relevant publications.Results: A total of 8876 articles were retrieved (of which 7476 were excluded according to the exclusion criteria). The literature indicates that not all assessed biomarkers return to baseline levels following smoking cessation during the study periods but that nine had potential for use in medium to long-term studies.Discussion and conclusion: In clinical studies, it is important to choose biomarkers that show the biological effect of cessation within the duration of the study.

A novel flow cytometric-based method to measure kinase inhibition in sputum from COPD subjects

Introduction

Janus kinases (JAKs) regulate inflammatory gene expression through phosphorylation of signal transducer and activator of transcription (STAT) proteins. Expression of STAT proteins is increased in chronic obstructive pulmonary disease (COPD), and may be involved in driving chronic inflammation. Oral JAK inhibitors are effective as anti-inflammatory therapy but exhibit dose-limiting adverse effects. Development of inhaled compounds would be enhanced by robust biomarkers that directly reflect the anti-inflammatory and pharmacological activity in the lung.

Methods

A novel flow cytometry assay was developed to measure STAT1 phosphorylation in sputum inflammatory cells. The standard sputum processing method was refined to improve sputum cell viability. The flow cytometric assay was used to assess the reproducibility of the measurement of STAT1 phosphorylation and the in vitro activity of a pan JAK-inhibitor on three separate visits in patients with COPD.

Results

Upregulation of STAT1 phosphorylation was measured following in vitro IFNγ stimulation of sputum macrophages (stimulated/unstimulated ratio 1.57; p<0.00001). Upregulation was inhibited following in vitro preincubation with a pan JAK-inhibitor (inhibited+stimulated/unstimulated ratio 0.97). STAT1 phosphorylation activity could only be measured in macrophages.

Conclusions

Sputum from patients with COPD can be used to reproducibly measure phospho-STAT expression in sputum macrophages. The flow cytometry-based method can be used to evaluate kinase inhibitors in vitro and subsequently in ex vivo studies. The assay is particularly useful for the assessment of inhaled compounds where whole blood assays may not be relevant.

Airway hydration and COPD

Chronic obstructive pulmonary disease (COPD) is one of the prevalent causes of worldwide mortality and encompasses two major clinical phenotypes, i.e., chronic bronchitis (CB) and emphysema. The most common cause of COPD is chronic tobacco inhalation. Research focused on the chronic bronchitic phenotype of COPD has identified several pathological processes that drive disease initiation and progression. For example, the lung's mucociliary clearance (MCC) system performs the critical task of clearing inhaled pathogens and toxic materials from the lung. MCC efficiency is dependent on: (1) the ability of apical plasma membrane ion channels such as the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na(+) channel (ENaC) to maintain airway hydration; (2) ciliary beating; and (3) appropriate rates of mucin secretion. Each of these components is impaired in CB and likely contributes to the mucus stasis/accumulation seen in CB patients. This review highlights the cellular components responsible for maintaining MCC and how this process is disrupted following tobacco exposure and with CB. We shall also discuss existing therapeutic strategies for the treatment of chronic bronchitis and how components of the MCC can be used as biomarkers for the evaluation of tobacco or tobacco-like-product exposure.

The role of the small airways in the pathophysiology of asthma and chronic obstructive pulmonary disease

Chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), represent a major social and economic burden for worldwide health systems. During recent years, increasing attention has been directed to the role of small airways in respiratory diseases, and their exact contribution to the pathophysiology of asthma and COPD continues to be clarified. Indeed, it has been suggested that small airways play a distinct role in specific disease phenotypes. Besides providing information on small airways structure and diagnostic procedures, this review therefore aims to present updated and evidence-based findings on the role of small airways in the pathophysiology of asthma and COPD. Most of the available information derives from either pathological studies or review articles and there are few data on the natural history of small airways disease in the onset or progression of asthma and COPD. Comparisons between studies on the role of small airways are hard to draw because both asthma and COPD are highly heterogeneous conditions. Most studies have been performed in small population samples, and different techniques to characterize aspects of small airways function have been employed in order to assess inflammation and remodelling. Most methods of assessing small airways dysfunction have been largely confined to research purposes, but some data are encouraging, supporting the utilization of certain techniques into daily clinical practice, particularly for early-stage diseases, when subjects are often asymptomatic and routine pulmonary function tests may be within normal ranges. In this context further clinical trials and real-life feedback on large populations are desirable.

Anti-inflammatory effects of salmeterol/fluticasone propionate 50/250 mcg combination therapy in Japanese patients with chronic obstructive pulmonary disease

PURPOSE

Using sputum neutrophils as the primary measure, and other inflammation biomarkers, this study evaluated the anti-inflammatory effects of the combination salmeterol 50 mcg and fluticasone propionate 250 mcg (SFC 250) in Japanese patients with chronic obstructive pulmonary disease (COPD).

PATIENTS AND METHODS

Patients were treated in a randomized, double-blind, parallel group, placebo-controlled trial with SFC 250 twice daily (n=26) or placebo (n=26) for 12 weeks. At the start and end of treatment, inflammation biomarkers (sputum and serum), lung function, and health status (COPD Assessment Test [CAT] questionnaire) were measured.

RESULTS

Although a numerical decrease in differential neutrophil count was observed from baseline, SFC 250 did not significantly reduce sputum neutrophils compared with placebo, nor were there significant changes from baseline in the other biomarkers (sputum or serum), lung function, or CAT, versus placebo. Squamous epithelial cell contamination in some sputum samples rendered them unacceptable for analysis, which reduced the sample size to n=19 (SFC 250) and n=10 (placebo). However, inclusion of contaminated samples did not affect the overall trend of the outcome. Ad hoc bootstrap statistical analysis showed a 27.9% (SFC 250) and 1.3% (placebo) decrease in sputum neutrophils. Sputum IL-8 decreased by 43.2% after SFC 250 but increased by 48.3% with placebo. Responder analyses showed 42% of patients had ≥20% decrease in neutrophils from baseline; and 47% of patients had a ≥200 pg/mL change in sputum IL-8 following SFC 250 versus 20% after placebo; both changes are considered clinically relevant.

CONCLUSION

This study provides additional information about inflammation in Japanese COPD patients and is the first to study the anti-inflammatory effects of SFC 250 in this context and population. In the primary analysis, SFC 250 did not produce significant changes from baseline in sputum neutrophil levels or other sputum or serum inflammatory markers compared with placebo. Secondary ad hoc statistical analysis showed that SFC 250 reduced the number of sputum neutrophils and IL-8 compared with placebo.

Inhaled corticosteroids increase siglec-5/14 expression in sputum cells of COPD patients

Recent studies show that several Siglec receptors, such as Siglec-8 and Siglec-14, may be important therapeutic targets in asthma and COPD. Siglecs are a family of lectins belonging to the immunoglobulin superfamily and recognize sialic acid residues of glycoproteins. Most of Siglecs have intracellular immunoreceptor tyrosine-based inhibitory motifs (ITIM), implicating them in the suppression of immunoreceptor signaling. Siglec-5/14 may be involved in the negative regulation of innate immune responses. The aim of this study was to analyze Siglec-5/14 expression in induced sputum cells of COPD patients in the following treatment combinations: (1) a long-acting beta2-agonist, formoterol; (2) formoterol combined with a long-acting antimuscarinic agent, tiotropium; and (3) formoterol combined with an inhaled corticosteroid or formoterol combined with tiotropium and with an inhaled corticosteroid. Siglec expression was assessed in sputum cells by flow cytometry using a specific monoclonal antibody. Double staining of cells indicated that Siglec-5/14 is expressed in monocyte/macrophages and neutrophils, but not in lymphocytes. Siglec-5/14 expression was significantly higher in patients receiving combined therapy including inhaled corticosteroids compared with patients taking only formoterol or formoterol + tiotropium. Our results suggest that inhaled corticosteroids may exert beneficial or negative effects, depending on the patients' phenotype, through increased immunosuppressive Siglec-5 or immunoactivatory Siglec-14 receptors, respectively.

Comparison of inflammatory markers in induced and spontaneous sputum in a cohort of COPD patients

BACKGROUND

Sputum induction is a non-invasive method for obtaining measurements of inflammation in the airways. Whether spontaneously sampled sputum can be a valid surrogate is unknown. The aim of this study was to compare levels of six inflammatory markers in sputum pairs consisting of induced and spontaneous sputum sampled on the same consultation either in a stable state or during exacerbations of chronic obstructive pulmonary disease (COPD).

METHODS

433 COPD patients aged 40-76, Global initiative for chronic Obstructive Lung Disease (GOLD) stage II-IV were enrolled in 2006/07 and followed every six months for three years. 356 patients were followed for potential exacerbations. Interleukin-6, interleukin-8, interleukin-18, interferon gamma-inducible protein-10, monokine induced by gamma interferon and tumor necrosis factor-alpha (IL-6, IL-8, IL-18, IP-10, MIG and TNF-α) were measured by bead based multiplex immunoassay in 60 paired sputum samples from 45 patients. Albumin was measured by enzyme immunoassay, for concentration correction. Culturing for bacterial growth was performed on 24 samples. Bland-Altman plots were used to assess agreement. The paired non-parametric Wilcoxon signed-rank test, the non-parametric Spearman's rank correlation test and Kruskal-Wallis test were used for statistical analyses. For all analyses, a p-value < 0.05 was considered significant.

RESULTS

Agreement between the two measurements was generally low for all six markers. TNF-α was significantly higher in spontaneous sputum at exacerbations (p = 0.002) and trending higher at the steady state (p = 0.06). Correlation coefficients between the levels of markers in induced and spontaneous sputum varied between 0.58 (IL-18) to 0.83 (IP-10). In spontaneous sputum IL-18 and MIG were higher in ex-smokers (p < 0.05). The levels of all markers were higher in GOLD stage III & IV except for IL-6 in spontaneous sputum and IL-18 in induced sputum, compared with GOLD stage II, although not statistically significant. In spontaneous sputum the levels of IL-6 were significantly higher if Haemophilus influenzae (HI) was not cultured.

CONCLUSION

We observed a low agreement and significant differences in inflammatory markers between induced and spontaneous sputum, both at steady state and exacerbations. We recommend considering sampling method when reporting on inflammatory markers in sputum.

Effects of woodsmoke exposure on airway inflammation in rural Guatemalan women

Background

More than two-fifths of the world’s population uses solid fuels, mostly biomass, for cooking. The resulting biomass smoke exposure is a major cause of chronic obstructive pulmonary disease (COPD) among women in developing countries.

Objective

To assess whether lower woodsmoke exposure from use of a stove with a chimney, compared to open fires, is associated with lower markers of airway inflammation in young women.

Design

We carried out a cross-sectional analysis on a sub-cohort of participants enrolled in a randomized controlled trial in rural Guatemala, RESPIRE.

Participants

We recruited 45 indigenous women at the end of the 18-month trial; 19 women who had been using the chimney stove for 18–24 months and 26 women still using open fires.

Measurements

We obtained spirometry and induced sputum for cell counts, gene expression of IL-8, TNF-α, MMP-9 and 12, and protein concentrations of IL-8, myeloperoxidase and fibronectin. Exhaled carbon monoxide (CO) and 48-hr personal CO tubes were measured to assess smoke exposure.

Results

MMP-9 gene expression was significantly lower in women using chimney stoves. Higher exhaled CO concentrations were significantly associated with higher gene expression of IL-8, TNF-α, and MMP-9. Higher 48-hr personal CO concentrations were associated with higher gene expression of IL-8, TNF- α, MMP-9 and MMP-12; reaching statistical significance for MMP-9 and MMP-12.

Conclusions

Compared to using an open wood fire for cooking, use of a chimney stove was associated with lower gene expression of MMP-9, a potential mediator of airway remodeling. Among all participants, indoor biomass smoke exposure was associated with higher gene expression of multiple mediators of airway inflammation and remodeling; these mechanisms may explain some of the observed association between prolonged biomass smoke exposure and COPD.

Intervention effect and dose-dependent response of tanreqing injection on airway inflammation in lipopolysaccharide-induced rats

OBJECTIVE

To assess the effect of Tanreqing injection on airway inflammation in rats.

METHODS

A rat model of airway inflammation was generated with lipopolysaccharide (LPS). Tanreqing injection was given by intratracheal instillation, and bronchoalveolar lavage fluid (BALF) from the right lung was collected. BALF total cell and neutrophil counts were then determined. In addition, BALF levels of inflammatory cytokines interleukin-13, cytokine-induced neutrophil chemoat-tractant-1, and tumor necrosis factor-alpha were measured using enzyme linked immunosorbent assay. The middle lobe of the right lung was stained with hematoxylin-eosin and histological changes examined.

RESULTS

LPS increased airway inflammation, decreased BALF inflammatory cell count, inflammatory cytokine levels, and suppressed leukocyte influx of the lung. The LPS-induced airway inflammation peaked at 24 h, decreased beginning at 48 h, and had decreased markedly by 96 h.

CONCLUSION

Tanreqing injection contains anti-inflammatory properties, and inhibits airway inflammation in a dose-dependent manner.

The effect of human antibacterial peptide LL-37 in the pathogenesis of chronic obstructive pulmonary disease

BACKGROUND

Previous research has shown that innate immune system was more important than the acquired immune system in the pathogenesis of COPD. LL-37 is the only human cathelicidin identified so far. As an integral part of the innate immune system, besides antibacterial activity, its chemotactic activity, damage repairing, influencing apoptosis and its cytotoxicity are attracting people's attention. The aim of the present study was to evaluate role of LL-37 in the pathogenesis of COPD.

METHODS

ELISA and immunohistochemistry were applied to investigate the expression of LL-37 in induced sputum and lung tissue of COPD patients. Bronchial epithelial cell (BEP2D) and alveolar epithelial cell (A549) were treated with LL-37 synthesis polypeptide in vitro to assess the role of LL-37 in inflammation and apoptosis.

RESULTS

We found that increased induced sputum levels of LL-37 in COPD patients were associated with airflow limitation, health status and exercise tolerance and the expressing intensity of LL-37 in both airway district and pulmonary alveoli area in COPD group significantly increased compared with control group. Through stimulation by CSE and LPS, the expression of LL-37 was increased in bronchial epithelial cell and alveolar epithelial cell. LL-37 synthesis polypeptide can promote the releasing of inflammatory factor IL-8 and induce apoptosis of bronchial epithelial cell and alveolar epithelial cell.

CONCLUSION

This study suggested that LL-37 may play important role in the pathogenesis of COPD and may be a possible novel therapeutic target in COPD.

Comparison of Symbicort® versus Pulmicort® on steroid pharmacodynamic markers in asthma patients

BACKGROUND

Combination therapy with inhaled corticosteroids (ICS) and long-acting β(2)-adrenergic agonists (LABA) is reported to have superior effects on controlling asthma symptoms to ICS alone; however, there is no molecular-based evidence to explain the clinical effects. Here, the effect of the ICS/LABA combination was compared with ICS on glucocorticoid receptor (GR) activation in sputum macrophages.

METHODS

In a randomised, double-blind cross-over placebo-controlled 6-visit study, 10 patients with mild asthma were given placebo, formoterol (Oxis(®) 12 μg), budesonide (Pulmicort(®) 200 μg :BUD200, or 800 μg :BUD800), or budesonide/formoterol combination (Symbicort(®)) as a single 100/6 μg (SYM100) or double 200/12 μg (SYM200) dose. Sputum macrophages were separated by plate adhesion from induced sputum. GR binding to the glucocorticoid-response elements on oligonucleotides (GR-GRE binding) was evaluated by ELISA. mRNA expression of MAP-kinase phosphatase (MKP)-1 and IL-8 were measured by quantitative RT-PCR.

RESULTS

GR-GRE binding was significantly increased after treatment with SYM100 (3.5 OD/10 μg protein, median, p < 0.05) versus placebo (1.3) and BUD200 (1.6), and the induction was higher than that of BUD800 (2.4). MKP-1 mRNA was increased and IL-8 mRNA was significantly inhibited by BUD800, SYM100 and SYM200 versus placebo.

CONCLUSIONS

The effects of SYM100 and SYM200 on GR activation were not different from that of BUD800 and superior to BUD200. Thus, it has been confirmed at a molecular level that inhaled combination therapy with a lower dose of budesonide has an equivalent effect to a high dose of budesonide alone. In addition, GR-GRE binding is found to be a valuable pharmacodynamic marker for steroid efficacy in clinical studies.

Innate immunity proteins in chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) may be caused by epithelial cell injury. Epithelial cells respond to injury by secreting innate immunity proteins. To investigate whether altered levels of innate immunity proteins are observed in COPD and IPF, the authors assessed secretory leukocyte protease inhibitor (SLPI), elafin, CC16, and beta-defensin-2 levels by enzyme-linked immunosorbent assay (ELISA) in sputum supernatants from COPD patients (n = 19), smokers without COPD (n = 21), and never-smokers (n = 10) and in BALF supernatants from patients with IPF (n = 11) and subjects without IPF (n = 11). CC16 levels were decreased, whereas SLPI and elafin levels were increased in COPD patients (0.8 [0-4.2] microg/mL, 2.5 [0.3-10.5] microg/mL, 213 [152-318] pg/mL, respectively) compared to smokers without COPD (1.8 [0.1-21.2] microg/mL, 0.8 [0.2-2.6] microg/mL, 172 [71-473] pg/mL, respectively) and never-smokers (0.5 [0-4.8] microg/mL, 0.1 [0.05-0.6] microg/mL, 188 [129-218] pg/mL, respectively) (CC16: P = .001; SLPI: P <.001; elafin: P = .041). beta-Defensin-2 was detected in smokers without COPD (98 [10-729] pg/mL) and never-smokers (74 [35-410] pg/mL), but not in COPD. SLPI and elafin levels did not differ between IPF patients and controls, but CC16 levels were increased in IPF (0.5 [0-2.3] versus 0.2 [0-0.3] microg/mL; P = .019). beta-Defensin-2 was not detected in BALF. In conclusion, in COPD, secretion of CC16 and beta-defensin-2 might be suppressed, whereas SLPI and elafin secretion is up-regulated. In IPF, only CC16 secretion is up-regulated.

Overview of novel therapeutic targets for asthma and chronic obstructive pulmonary disease

Obstructive lung diseases, in particular asthma and chronic obstructive pulmonary disease, are a worldwide health problem that is increasing in incidence. While significant progress has been made in the control of symptoms, further advances must be made in modifying the clinical situation in terms of disease progression. Numerous pathogenetic studies have demonstrated that inflammatory responses play a crucial role in the development of chronic lung obstruction, while current molecular findings have provided a myriad of new and promising therapeutic targets. The aim of this article is to provide an overview of clinically and pharmacologically relevant targets for asthma and chronic obstructive pulmonary diseases, considering currently investigated therapeutic approaches.

Local inflammation occurs before systemic inflammation in patients with COPD

BACKGROUND AND OBJECTIVE

COPD is associated not only with an abnormal inflammatory response in the lung but also with systemic inflammation, including systemic oxidative stress, activation of circulating inflammatory cells and increased circulating levels of inflammatory cytokines. Understanding the nature and course of systemic inflammation in COPD is important given the potential for anti-inflammatory therapy. This study explored whether local and systemic inflammation occur concurrently in patients with COPD.

METHODS

Forty-four patients with stable COPD, 10 smoking controls and 10 non-smoking controls were enrolled in this observational study. Induced sputum and peripheral blood samples were obtained simultaneously for measurement of inflammatory cell numbers and the concentrations of IL-6 and CRP.

RESULTS

The total number of cells in the sputum total cell number, percentage of neutrophils and the concentration of IL-6 were significantly higher in smoking controls and patients with COPD than in non-smoking controls (P < 0.05 and P < 0.01, respectively). As the disease stage progressed, airway inflammatory cells and IL-6 levels increased. CRP levels in sputum were significantly higher in stage II, III and IV COPD patients than in smoking and non-smoking controls (P < 0.01). However, the peripheral WCC and percentage of neutrophils were similar in patients with COPD, smoking and non-smoking controls. Circulatory concentrations of IL-6 and CRP in stages III and IV COPD patients were significantly higher than in smoking and non-smoking controls (P < 0.05 and P < 0.01, respectively). Additionally, there were positive correlations between sputum and blood IL-6 and CRP levels (r = 0.566, P < 0.01 and r = 0.443, P < 0.01, respectively).

CONCLUSIONS

The increase in the inflammatory cell population and IL-6 and CRP levels in the airway may occur earlier than in the peripheral blood, and reflect the degree of airflow limitation better than do peripheral blood measurements. Systemic inflammation may be present in patients with severe or very severe COPD.

Maintained smoking cessation for 6 months equilibrates the percentage of sputum CD8+ lymphocyte cells with that of nonsmokers

Little is known about the longitudinal effects of smoking cessation on sputum inflammatory cells. We aimed to investigate the changes in sputum inflammatory cells and T-lymphocyte subpopulations after 6 and 12 months smoking cessation. Induced sputum was obtained from 68 healthy smokers before and after 6 months (n = 21) and 1 year (n = 14) smoking cessation and from ten healthy never-smokers. Inflammatory cells were identified by morphology and T-lymphocyte subpopulations by flow cytometry. Sputum macrophages were decreased after 12 months of smoking cessation in comparison to baseline, while neutrophils increased. Moreover, CD8+ T-cells were decreased in smokers before smoking cessation compared to never-smokers and increased in smokers after 6 months of smoking cessation in comparison to baseline; result that was maintained after 1 year of smoking cessation. These novel findings indicate that smoking cessation can equilibrate certain inflammatory cells of smokers with those of nonsmokers, within 6 months of smoking cessation.

The small airways and distal lung compartment in asthma and COPD: a time for reappraisal

The involvement of small airways in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD) has been debated for a long time. However, a proper definition of small airway disease is still lacking, and neither a widely accepted biomarker nor a functional parameter to assess small airway abnormalities and to explore the effect of tested compounds on small airways is available. Aiming towards increased knowledge and consensus on this topic, this perspective paper intends to (i) strengthen awareness among the scientific community on the role of small airways in asthma and COPD; (ii) examine the pros and cons of some biological, functional and imaging parameters in the assessment of small airway abnormalities; and (iii) discuss the evidence for distal airway pharmacological targeting in asthma and COPD.

Chronic obstructive pulmonary disease and neutrophil infiltration: role of cigarette smoke and cyclooxygenase products

Cigarette smoke is the main cause of chronic obstructive pulmonary disease (COPD), where it can contribute to the observed airway inflammation. PGE(2) is produced within human airways, and both pro- and anti-inflammatory activities have been reported. We quantitated PGE(2) concentrations in induced sputum supernatants from different groups of subjects and correlated the obtained values to neutrophil infiltration as well as to the expression of cyclooxygenase-2 (COX-2). Cigarette smoke extract (CSE) was used to evaluate the effect of smoking on COX-2 and PGE(2) receptor expression as well as on PGE(2) release in neutrophils and alveolar macrophages (AM) obtained from normal donors. The effects of PGE(2) and of PGE receptor agonists and antagonists were evaluated on the adhesion of neutrophil to a human bronchial epithelial cell line (16HBE). PGE(2) levels, COX-2 expression, and neutrophil infiltration were significantly higher in normal smokers and COPD smokers (P < 0.0001) compared with controls and COPD former smokers. Induced sputum supernatant caused neutrophil adhesion to 16HBE that was significantly reduced, in COPD smokers only, by PGE(2) immunoprecipitation. In vitro experiments confirmed that CSE increased PGE(2) release and COX-2 and PGE(2) receptor expression in neutrophils and AM; PGE(2) enhanced the adhesion of neutrophils to 16HBE, and a specific E-prostanoid 4 (EP(4)) receptor antagonist blunted its effect. These results suggest that CSE promote the induction of COX-2 and contributes to the proinflammatory effects of PGE(2) in the airways of COPD subjects.

The role of bacteria in airway inflammation in exacerbations of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Bacteria cause approximately half of all chronic obstructive pulmonary disease exacerbations. The purpose of this review is to evaluate the status of research on the role of bacteria in airway inflammation during exacerbations and the mechanisms by which bacterial antigens induce inflammation.

RECENT FINDINGS

Bacteria in the airways of adults with chronic obstructive pulmonary disease release antigens including endotoxin, peptidoglycan fragments, lipoproteins, and other molecules into the airways. These bacterial antigens induce potent inflammatory effects in the airways. Bacterial exacerbations are associated with systemic inflammation. Studies of Haemophilus influenzae, the most common bacterial cause of exacerbations, reveal that strains associated with exacerbations induce more inflammation compared to colonizing strains. H. influenzae antigens induce production of interleukin-8 and tumor necrosis factor-alpha, activate Toll-like 2 receptors, activate NFkappaB and p38 mitogen-activated protein signaling pathways, and have other inflammatory effects.

SUMMARY

Research on the role of bacteria in causing inflammation in chronic obstructive pulmonary disease has been neglected for decades. Research should be directed at further evaluating the role of bacterial antigens in airway inflammation. Reducing or modulating bacterial infection of the airways in chronic obstructive pulmonary disease has the potential to reduce airway inflammation by eliminating an important inciting cause.

Airway inflammation and cellular stress in noneosinophilic atopic asthma

STUDY OBJECTIVES

It has been suggested that patients with noneosinophilic asthma (NEA) show increased numbers of sputum neutrophils and a lack of response to therapy with corticosteroids, which are features that are commonly related to COPD. The aim of our study was to test the hypothesis that airway inflammation in NEA patients is different from that seen in patients with eosinophilic asthma (EA) and is similar to COPD.

DESIGN

Sputum cellular stress markers and neutrophilic and eosinophilic fluid-phase mediators were analyzed in asthma and COPD patients. NEA patients were identified based on a sputum eosinophil count of < or = 2.2% of the total nonsquamous cell count, and were compared to EA and COPD patients.

SETTING

University Hospital of Heraklion, Department of Thoracic Medicine.

PATIENTS

A total of 37 atopic asthmatic patients and 25 patients with COPD.

MEASUREMENTS

Sputum cell counts, cellular expression of heme oxygenase-1, inducible nitric oxide synthase, and nitrotyrosine, and sputum levels of eosinophilic cationic protein (ECP), myeloperoxidase (MPO), interleukin-8, and granulocyte macrophage colony-stimulating factor.

RESULTS

A total of 17 asthmatic patients (46%) belonged to the NEA group and 20 patients (54%) to the EA group. Patients with NEA showed no difference in neutrophil counts, fluid-phase mediators, or cellular stress markers compared to patients with EA. Compared to COPD patients, NEA patients showed the following significant differences: lower total cell counts (p < 0.03); lower neutrophil counts (p < 0.01); lower nitrotyrosine positive cell counts (p < 0.003); lower ECP levels (p < 0.005); lower MPO levels (p < 0.000); higher lymphocyte counts (p < 0.01); and higher macrophage counts (p < 0.03).

CONCLUSIONS

Despite low eosinophil counts, airway inflammation in NEA patients may share common features with that in EA patients but is distinct from COPD. Larger studies are needed to investigate further the clinical and inflammatory characteristics of NEA before we are able to categorize asthma patients into those with or without eosinophilic inflammation.

Chronic obstructive pulmonary disease: histopathology, inflammation and potential therapies

Chronic obstructive pulmonary disease (COPD) is a major worldwide health burden with increasing morbidity, mortality and health care cost. It is a slowly progressive chronic inflammatory condition that affects the conducting airways (both large and small) and lung parenchyma. In COPD, inflammation is evident early on even in mild disease and increases with disease severity. Recent advances in our knowledge demonstrate, by comparison with asthma, the distinctive, "abnormal" or exaggerated inflammatory processes involved in the pathogenesis of COPD and thus identify novel therapeutic targets that could potentially impact on disease progression. The present review will focus on what is known of the abnormal inflammatory response of COPD in different regions of the conducting airways and lung. Novel, potentially promising approaches to therapy are presented.

Human cathelicidin LL-37 is a chemoattractant for eosinophils and neutrophils that acts via formyl-peptide receptors

BACKGROUND

Inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD) are characterized by the presence of eosinophils and neutrophils. However, the mechanisms that mediate the influx of these cells are incompletely understood. Neutrophil products, including neutrophil elastase and antimicrobial peptides such as neutrophil defensins and LL-37, have been demonstrated to display chemotactic activity towards cells from both innate and adaptive immunity. However, chemotactic activity of LL-37 towards eosinophils has not been reported. Therefore, the aim of the present study was to investigate the chemotactic activity of LL-37 for eosinophils and to explore the mechanisms involved in LL-37-mediated attraction of neutrophils and eosinophils.

METHODS

Neutrophils and eosinophils were obtained from venous blood of healthy donors. Chemotaxis was studied using a modified Boyden chamber technique. Involvement of formyl-peptide receptors (FPRs) was studied using the antagonistic peptide tBoc-MLP. Activation of the mitogen-activated protein kinase (MAPK) ERK1/2 was studied by Western blotting using antibodies directed against phosphorylated ERK1/2.

RESULTS

Our results show that LL-37 chemoattracts both eosinophils and neutrophils. The FPR antagonistic peptide tBoc-MLP inhibited LL-37-induced chemotaxis. Whereas the FPR agonist fMLP activated ERK1/2 in neutrophils, LL-37 did not, indicating that fMLP and LL-37 deliver different signals through FPRs.

CONCLUSIONS

LL-37 displays chemotactic activity for eosinophils and neutrophils, and this activity is mediated via an FPR. These results suggest that LL-37 may play a role in inflammatory lung diseases such as asthma and 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.

Can inhaled fluticasone alone or in combination with salmeterol reduce systemic inflammation in chronic obstructive pulmonary disease? Study protocol for a randomized controlled trial [NCT00120978]

Background

Systemic inflammation is associated with various complications in chronic obstructive pulmonary disease including weight loss, cachexia, osteoporosis, cancer and cardiovascular diseases. Inhaled corticosteroids attenuate airway inflammation, reduce exacerbations, and improve mortality in chronic obstructive pulmonary disease. Whether inhaled corticosteroids by themselves or in combination with a long-acting β₂-adrenoceptor agonist repress systemic inflammation in chronic obstructive pulmonary disease is unknown. The Advair Biomarkers in COPD (ABC) study will determine whether the effects of inhaled corticosteroids alone or in combination with a long-acting β₂-adrenoceptor agonist reduce systemic inflammation and improve health status in patients with chronic obstructive pulmonary disease.

Methods/Design

After a 4-week run-in phase during which patients with stable chronic obstructive pulmonary disease will receive inhaled fluticasone (500 micrograms twice daily), followed by a 4-week withdrawal phase during which all inhaled corticosteroids and long acting β₂-adrenoceptor agonists will be discontinued, patients will be randomized to receive fluticasone (500 micrograms twice daily), fluticasone/salmeterol combination (500/50 micrograms twice daily), or placebo for four weeks. The study will recruit 250 patients across 11 centers in western Canada. Patients must be 40 years of age or older with at least 10 pack-year smoking history and have chronic obstructive pulmonary disease defined as forced expiratory volume in one second to vital capacity ratio of 0.70 or less and forced expiratory volume in one second that is 80% of predicted or less. Patients will be excluded if they have any known chronic systemic infections, inflammatory conditions, history of previous solid organ transplantation, myocardial infarction, or cerebrovascular accident within the past 3 months prior to study enrolment. The primary end-point is serum C-reactive protein level. Secondary end-points include circulating inflammatory cytokines such as interleukin-6 and interleukin-8 as well as health-related quality of life and lung function.

Discussion

If inhaled corticosteroids by themselves or in combination with a long-acting β₂-adrenoceptor agonist could repress systemic inflammation, they might greatly improve clinical prognosis by reducing various complications in chronic obstructive pulmonary disease.

Laboratory markers for COPD in “susceptible” smokers

Smoking is the major risk factor for the development of chronic obstructive pulmonary disease. Apart from the important preventive steps of smoking cessation, there are no other specific treatments for COPD that are as effective in reversing the condition. However, only a relatively small proportion of smokers-about 15%-will develop clinically relevant COPD. Allergy, airway hyper-responsiveness (AHR) to methacholine, and gender differences have been proposed to identify individuals susceptible to the development of COPD. However, variable response to cigarette smoke clearly suggests genetic susceptibility. Among the COPD candidate genes are those (a) that effect the production of proteases and antiproteases, (b) modulate the metabolism of toxic substances in cigarette smoke, (c) are involved with mucocilliary clearance, and (d) that influence inflammatory mediators. Recently, sputum cells from smokers with and without COPD were tested for Microsatellite DNA Instability (MSI) with positive results. This finding suggests that MSI can be a useful marker of genetic susceptibility and thereby indicate destabilization of the genome in the "susceptible" smoker. Nevertheless, COPD lacks established viable biomarkers to predict and monitor disease progression and outcome variables. Such monitoring tools may be induced sputum, exhaled air condensate, peripheral blood, urine, bronchial biopsies, and bronchoalveolar lavage fluid (BALF). This review summarizes recent research on potential laboratory markers in smokers and subsequent COPD development.

Neutrophilic inflammation and IL-8 levels in induced sputum of alpha-1-antitrypsin PiMZ subjects

BACKGROUND

Severe alpha-1-antitrypsin deficiency (AATD), due to homozygosity for the protease inhibitor (Pi) Z allele, is a genetic risk factor for chronic obstructive pulmonary disease (COPD). In a previous study the sputum of severe AATD subjects with airflow obstruction showed a pattern of cellular inflammation similar to COPD patients. It is uncertain whether heterozygotes for the Z allele or intermediate deficiency (PiMZ) have an increased risk of developing COPD.

METHODS

Sputum cell counts and the supernatant level of the neutrophil chemoattractant interleukin (IL)-8 were investigated by sputum induction in 10 non-smoker asymptomatic PiMZ subjects with normal pulmonary function, 10 patients with stable COPD, and 10 age matched normal subjects. Data are expressed as mean (SD).

RESULTS

The mean (SD) number of neutrophils was significantly higher (p<0.01) in the sputum of PiMZ subjects (84.5 (22.2) x10(4)/ml) and patients with COPD (126.9 (18.8) x10(4)/ml) than in matched normal subjects (55.0 (8.7) x10(4)/ml). IL-8 levels were increased in PiMZ subjects (828.5 (490.6) ng/ml; median 1003.0 ng/ml; range 1260-100 ng/ml) and in COPD patients (882.5 (524.3) ng/ml; median 934.9 ng/ml; range 1506-258 mg/ml) compared with normal subjects (3.5 (0.5) ng/ml; median 3.5 ng/ml; range 4.5-2.5 ng/ml). There was a significant positive correlation between IL-8 supernatant concentration and neutrophil count in PiMZ subjects (p = 0.036; r = 0.66). An inverse correlation was observed between the percentage of neutrophils and forced expiratory volume in 1 second (% predicted) in patients with COPD (p = 0.04; r = -0.43).

CONCLUSIONS

These findings indicate that PiMZ subjects without airflow obstruction may have an IL-8 related neutrophilic inflammation in the airways, similar to stable COPD patients, suggesting an increased risk of developing pulmonary changes.

Utility of exhaled breath condensates in chronic obstructive pulmonary disease: a critical review

PURPOSE OF REVIEW

Evaluation of the utility of exhaled breath condensates in chronic obstructive pulmonary disease.

RECENT FINDINGS

Exhaled breath condensates have recently been introduced as a simple, noninvasive method of sampling respiratory fluid in inflammatory lung disorders, including chronic obstructive pulmonary disease. Increases in condensate concentrations of at least 12 markers of inflammation have been reported in these disorders. Furthermore, condensate pH appears to be decreased in both chronic obstructive lung disease and bronchial asthma. This has been referred to as acidopnea and could reflect airway acidification by inflammatory cells. Although safer and more convenient than bronchoalveolar lavage, interpretation of condensate data is complicated by uncertainty regarding the source of condensate solutes and by variable dilution of respiratory droplets from condensed water vapor, which represents more than 99.9% of condensate volumes. This dilution can be estimated from the dilution of plasma constituents such as urea or electrolytes. Because the principal buffer in condensate is NH4, much of which is derived from bacterial degradation of urea in the mouth, condensate pH measurements may not provide accurate estimates of airway pH. Nevertheless, acidification of condensate may be indicative of gastroesophageal reflux, which frequently occurs in obstructive lung diseases and may contribute to cough and bronchospasm.

SUMMARY

It is too early to tell how useful condensate studies will be to pulmonary investigators and clinicians. Realization of the enormous potential of this approach will require a thorough understanding of the manner in which these solutions are generated and how they should be analyzed.

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.

Cough in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) most commonly complain of cough, production of phlegm and breathlessness. The cough reflex sensitivity is heightened compared with that in healthy volunteers and is similar to that in subjects with asthma. The degree of airflow obstruction does not predict cough reflex sensitivity or objective cough counts, implying an independent process. Objective cough rates seem to be relatively low in COPD, despite frequent reporting of the symptom by patients. The relative contribution of cough to disability in COPD seems to be small, if assessed by subjective reporting. Effective treatments for cough in COPD have not yet been identified. Improved outcome measures of cough, a better understanding of the mechanisms underlying cough, and the importance of cough to patients is required to progress in this field.

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.

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.

Inflammatory cell profiles and T-lymphocyte subsets in chronic obstructive pulmonary disease and severe persistent asthma

BACKGROUND

Severe persistent asthma (SPA) and chronic obstructive pulmonary disease (COPD) are both associated with non-reversible airflow limitation and airway neutrophilia.

OBJECTIVE

To compare inflammatory cell profiles and T lymphocyte subsets between SPA and COPD patients with similar severity of airflow limitation.

METHODS

Sputum induction and lung function tests were performed in 15 COPD patients aged (mean+/-SD) 68+/-8 years, ex-smokers, mean forced expiratory volume in 1 s (FEV1) 45% of predicted (% pred) and 13 SPA aged 55+/-10 years, non-smokers, mean FEV(1) 49% pred. All patients were on inhaled steroid treatment. Eight asthmatics exhibited irreversible airflow limitation. Differential cell count, metachromatic cell count and double immunocytochemistry for the analysis of T lymphocyte subsets were performed on sputum slides.

RESULTS

COPD patients had increased sputum neutrophils in comparison with SPA (P<0.03), but similar to SPA with fixed obstruction. In COPD sputum neutrophils negatively correlated with the lung transfer factor for carbon monoxide (KCO) (r=-0.462, P=0.04). SPA showed significantly increased eosinophils and metachromatic cells vs. COPD patients (P<0.04, P<0.007, respectively). Increased CD4/CD8 and decreased CD4-IFN-gamma/CD4-IL4+ cell ratio (P<0.001) were found in SPA vs. COPD. In SPA, CD4/CD8+ cell ratio correlated with sputum eosinophils (r=0.567, P=0.04).

CONCLUSION

In spite of treatment with inhaled steroids, SPA and COPD exhibit distinct sputum inflammatory cell patterns, although SPA with fixed airflow limitation and COPD patients have similar numbers of neutrophils.