Background: Considerable research has been conducted into the nature of airway inflammation in chronic obstructive pulmonary disease (COPD) but the relationship between proximal airways inflammation and both dynamic collapse of the peripheral airways and HRCT determined emphysema severity remains unknown. A number of research tools have been combined to study smokers with a range of COPD severities classified according to the GOLD criteria. Methods: Sixty five subjects (11 healthy smokers, 44 smokers with stage 0-IV COPD, and 10 healthy nonsmokers) were assessed using lung function testing and HRCT scanning to quantify emphysema and peripheral airway dysfunction and sputum induction to measure airway inflammation. Results: Expiratory HRCT measurements and the expiratory/inspiratory mean lung density ratio (both indicators of peripheral airway dysfunction) correlated more closely in smokers with the severity of airflow obstruction (r = 20.64, p,0.001) than did inspiratory HRCT measurements (which reflect emphysema severity; r = 20.45, p,0.01). Raised sputum neutrophil counts also correlated strongly in smokers with HRCT indicators of peripheral airway dysfunction (r = 0.55, p,0.001) but did not correlate with HRCT indicators of the severity of emphysema. Conclusions: This study suggests that peripheral airway dysfunction, assessed by expiratory HRCT measurements, is a determinant of COPD severity. Airway neutrophilia, a central feature of COPD, is closely associated with the severity of peripheral airway dysfunction in COPD but is not related to the overall severity of emphysema as measured by HRCT.

No abstract

Cigarette smoke induces significant changes in oxidant defense responses; some of these are further amplified, but not in a linear fashion, in individuals who develop COPD.

Airway neutrophilia is a prominent feature of chronic obstructive pulmonary disease. As cigarette smoke (CS) and epidermal growth factor (EGF) both cause release of interleukin-8 (IL-8) from epithelial cells in vitro, we investigated whether autocrine ligands for the EGF receptor (EGFR) are involved in this proinflammatory response to CS. NCI-H292 or primary bronchial epithelial cells were cultured with or without cigarette smoke extract (CSE) or EGF for 6-48 h. We then tested culture supernatants for lactate dehydrogenase activity to assess cell viability, and for IL-8 and EGFR ligands by ELISA; quantitative RT-PCR was used to measure IL-8 and EGFR ligand mRNA. EGF and low concentrations of CSE both promoted cell survival and caused enhanced transcription and release of IL-8. Similarly, levels of mRNA encoding transforming growth factor alpha (TGF-alpha), heparin-binding EGF-like growth factor, and amphiregulin (AR) were increased, as was shedding of TGF-alpha and AR protein into the culture medium. With the exception of AR gene transcription, the CS-induced responses were blocked by the EGFR-selective kinase inhibitor AG1478. Furthermore, ~ 45% of CS-induced IL-8 release was inhibited by a neutralising anti-EGFR. Our data indicate that secretion of IL-8 in response to CSE is dependent on EGFR activation and that autocrine production of TGF-alpha makes a substantial contribution to this response.

Background: Airway epithelial goblet cell hyperplasia is known to occur in chronic smokers. Although the epidermal growth factor receptor has been implicated in this process, neither ErbB receptor expression nor the mucosecretory phenotype of the epithelium have been characterised in current smokers. Methods: Bronchial biopsies obtained from non-smokers (n = 10) and current smokers, with or without chronic obstructive pulmonary disease (n = 51), were examined immunohistochemically to measure the expression of epidermal growth factor receptor, ErbB2, ErbB3, ErbB4 and mucin subtypes (MUC2, MUC5AC and MUC5B) in the bronchial epithelium. The results were correlated with neutrophil counts measured in the airway wall and induced sputum. Results: Epidermal growth factor receptor, ErbB3 and MUC5AC expression, in addition to PAS staining, were significantly increased in all smokers compared with non-smokers, irrespective of the presence of chronic obstructive pulmonary disease. MUC5AC expression was significantly associated with both PAS staining and ErbB3 expression; no correlation was observed between either mucin or ErbB receptor expression and neutrophil counts. Conclusions:The results suggest that long term current smoking induces enhanced epidermal growth factor receptor, ErbB3, and MUC5AC expression in vivo; these increases are not associated with the presence of neutrophilic inflammation. ErbB receptors may contribute to epithelial responses to cigarette smoke.

AimsTo quantify the extent of squamous metaplasia in bronchial biopsies and relate it to the presence of chronic obstructive pulmonary disease (COPD), a smoking-related pathology.MethodsBronchial biopsies (n = 15 in each group) from smokers with COPD GOLD stage1 and GOLD stage2, smokers without COPD and healthy non-smokers were stained immunohistochemically with a panel of antibodies that facilitated the identification of pseudostratified epithelium and distinction of squamous metaplasia and squamous epithelium from tangentially cut epithelium. The percentage length of each of these epithelial phenotypes was measured as a percent of total epithelial length using computerised image analysis. Sections were also stained for carcinoembryonic antigen and p53, early markers of carcinogenesis, and Ki67, and the percentage epithelial expression measured.ResultsThe extent of squamous metaplasia was significantly increased in both COPD1 and COPD2 compared to healthy smokers and healthy non-smokers. The amount of fully differentiated squamous epithelium was also increased in COPD1 and COPD2 compared to healthy non-smokers, as was the expression of carcinoembryonic antigen. These features correlated with one other.ConclusionIn subjects with COPD there is a loss of pseudostratified epithelium accompanied by an increase in squamous metaplasia with transition into a fully squamous epithelium and expression of early markers of carcinogenesis.

ADAM9 levels are increased in COPD lungs and linked to key clinical variables. Adam9 promotes emphysema development, and large and small airway disease in mice. Inhibition of ADAM9 could be a therapeutic approach for multiple COPD phenotypes.

No abstract