Publications

No abstract is provided for this article.

No abstract is provided for this article.

There has been increasing interest in the use of newer, culture-independent techniques to study the airway microbiome of COPD patients. We investigated the relationships between the three common potentially pathogenic microorganisms (PPMs) Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, as detected by quantitative PCR (qPCR), and inflammation and health status in stable patients in the London COPD cohort. We prospectively collected sputum, serum and plasma samples for analysis of airway bacterial presence and load, and airway and systemic inflammation from 99 stable COPD patients between January 2011 and October 2012. Health status was measured with St George’s Respiratory Questionnaire and COPD Assessment Test. Airway inflammation and plasma fibrinogen, but not C-reactive protein, were greater in samples with PPM detection (p < 0.001, p = 0.049 and p = 0.261, respectively). Increasing total bacterial load was associated with increasing airway (p < 0.01) but not systemic inflammation (p > 0.05). Samples with high total bacterial loads had significantly higher airway inflammation than both samples without PPM detection and those with lower loads. Haemophilus influenzae presence was associated with significantly higher levels of airway but not systemic inflammation for all given pathogen loads (p < 0.05), and was significantly greater than with other PPMs. No association was observed between inflammation and health status (p > 0.05). Airway and systemic inflammation, as measured by fibrinogen, is greater in stable COPD patients with PPMs detected using the culture-independent qPCR technique. The airway, but not systemic inflammatory response, appears to have a total pathogen-load threshold and appears attributable to Haemophilus influenzae. However, discordance between inflammation and health status was observed.

Cigarette smoke is the major cause of chronic obstructive pulmonary disease (COPD), a chronic inflammatory disease of the airway. The increased expression of inflammatory proteins results from enhanced gene transcription, as these mediators are induced in a cell-specific manner. Changes in transcription depend on chromatin remodeling and the relative activities of histone acetyl-transferases (HATs) and histone deacetylases (HDACs). We have shown that cigarette smoke reduces the expression of HDAC2 expression and HDAC activity in biopsies and alveolar macrophages. Cigarette smoke also enhanced IL-1β–induced expression of tumor necrosis factor α (TNF-α) by alveolar macrophages. TNF-α release was enhanced by the HDAC inhibitor Trichostatin A and correlated significantly with HDAC activity. In addition, we show that glucocorticoid-responsiveness is reduced in these cells and correlates with HDAC activity. Using a macrophage cell line, we show that hydrogen peroxide mimics cigarette smoke effects on HDAC activity and markedly attenuates dexamethasone inhibition of cytokine release. These results offer the first evidence for a suppressive effect of cigarette smoke on histone acetylation status. Reduced HDAC expression may account for the enhanced expression of inflammatory mediators such as GM-CSF, IL-8 and TNF-α by cigarette smoke seen in lavage samples of smokers and patients with COPD. In addition, this mechanism may account for the reduced effectiveness of glucocorticoids in COPD.

No abstract is provided for this article.

Interleukin (IL)-10 is an anti-inflammatory cytokine, but its role in cigarette smoke (CS)-induced inflammation and chronic obstructive pulmonary disease (COPD) has not been fully elucidated. The purpose of this study was to investigate the effect of IL-10 deficiency on CS-induced pulmonary inflammation in mice in vivo and in vitro.IL-10-deficient and wild-type control mice with a C57BL6/J genetic background were exposed to CS, and inflammatory cells in bronchoalveolar lavage fluid (BALF) and mRNA of cytokines in lung were evaluated with enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR).During 12 days of daily CS exposure to wild-type mice, neutrophil counts in BAL fluid and tumor necrosis factor (TNF)-α mRNA expression were increased, peaked at day 8, and then declined on day 12 when the level of IL-10 reached its peak. In IL-10-deficient mice, neutrophil recruitment and TNF-α mRNA levels induced by CS exposure were significantly greater than those in wild-type mice. Keratinocyte-derived chemokine (KC; murine ortholog of human CXCL8) and granulocyte macrophage colony-stimulating factor (GM-CSF) mRNA levels or matrix metalloproteinase(MMP)-9 protein levels were not correlated with neutrophil count.IL-10 had a modulatory effect on CS-induced pulmonary neutrophilic inflammation and TNF-α expression in mice in vivo and therefore appears to be an important endogenous suppressor of airway neutrophilic inflammation.