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Pentraxin (PTX)3 is involved in antimicrobial defence, apoptotic cell clearance and extracellular matrix stability. As these processes are altered in chronic obstructive pulmonary disease (COPD), we aimed to investigate PTX3 expression in patients with this disease. PTX3 expression was quantified by immunohistochemical staining of lung tissue from never-smokers, smokers without COPD, and in patients with COPD of Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I, II and III-IV. mRNA expression was examined in total lung tissue by quantitative RT-PCR. PTX3 concentration was measured in induced sputum and plasma by ELISA. PTX3 is mainly localised in the interstitium of the small airways and alveolar walls. There were no significant differences in pulmonary, sputum and plasma PTX3 expression between study groups. However, PTX3 expression in small airways correlated significantly with forced expiratory volume in 1 s (r = 0.35, p = 0.004). In the alveolar walls, PTX3 expression correlated significantly with carbon monoxide transfer coefficient (r = 0.28, p = 0.04). In sputum, PTX3 levels were highly correlated with the number of neutrophils. Finally, systemic levels of PTX3 tended to be lower in severe COPD compared with mild COPD. In COPD, airflow limitation and reduced transfer coefficient for carbon monoxide are associated with lower pulmonary interstitial expression of PTX3.

The Hedgehog signalling pathway plays an important role in lung morphogenesis and cellular responses to lung injury. A genome-wide association study has demonstrated that two single nucleotide polymorphisms (SNPs) near the Hedgehog-interacting protein (Hip) gene, SNP identifiers rs1828591 and rs13118928, are associated with risk of chronic obstructive pulmonary disease (COPD). The aim of the present study was to validate the observed association between genetic variation near the Hip gene and COPD, and to investigate whether risk estimates were modified by smoking behaviour. The association between the Hip gene SNPs and COPD was investigated in the Rotterdam Study by logistic regression analyses, adjusted for several covariates. In addition, an association meta-analysis was performed that included data from the genome-wide association study on COPD. Both SNPs were significantly associated with risk of COPD (OR 0.80; 95% CI 0.72-0.91). Homozygosity for the minor G allele resulted in a decreased risk of COPD of approximately 40% (95% CI 0.47-0.78). There was a significant interaction with the number of pack-years of smoking (p = 0.004). The meta-analysis yielded an odds ratio for COPD of 0.80 per additional G allele (p = 3.4 x 10(-9)). Genetic variation near the Hip gene was significantly associated with risk of COPD, depending on the number of pack-years of smoking.

In chronic obstructive pulmonary disease (COPD), chronic inflammation is accompanied by peribronchial lymphoid aggregates. Lymphotoxin (LT)-alpha, crucial in secondary lymphoid organogenesis, may be involved in lymphoid neogenesis. We examined cigarette smoke (CS)-induced pulmonary lymphoid neogenesis and inflammation in vivo in LTalpha knockout (LTalpha(-/-)) and wild-type (WT) mice and studied the expression of lymphoid chemokines by lung fibroblasts in vitro. T-cell numbers (in bronchoalveolar lavage fluid (BALF) and lungs) and lymphoid aggregate numbers were significantly higher in air-exposed LTalpha(-/-) mice than in WT animals, and increased upon chronic CS exposure in both genotypes. In contrast, local immunoglobulin A responses upon chronic CS exposure were attenuated in LTalpha(-/-) mice. CXC chemokine ligand (CXCL) 13 and CC chemokine ligand (CCL) 19 mRNA in total lung and CXCL13 protein level in BALF increased upon CS exposure in WT, but not in LTalpha(-/-) mice. In vitro lymphotoxin-beta receptor (LTbetaR) stimulation induced CXCL13 and CCL19 mRNA in WT lung fibroblasts. Furthermore, in vitro exposure to CS extract upregulated CXCL13 mRNA expression in WT, but not in LTbetaR(-/-), lung fibroblasts. In this murine model of COPD, CS induces pulmonary expression of lymphoid chemokines CXCL13 and CCL19 in a LTalphabeta-LTbetaR-dependent fashion. However, LTalpha is not required for CS-induced pulmonary lymphocyte accumulation and neogenesis of lymphoid aggregates.

Chronic obstructive pulmonary disease (COPD) is characterised by a local pulmonary inflammatory response to respiratory pollutants and by systemic inflammation. Tumour necrosis factor (TNF)-alpha has been implicated in systemic effects of COPD and operates by binding the p55 (R1) and p75 (R2) TNF-alpha receptors. To investigate the contribution of each TNF-alpha receptor in the pathogenesis of COPD, the present study examined the effects of chronic air or cigarette smoke (CS) exposure in TNF-alpha R1 knockout (KO) mice, TNF-alpha R2 KO mice and wild type (WT) mice. CS was found to significantly increase the protein levels of soluble TNF-alpha R1 (by four-fold) and TNF-alpha R2 (by 10-fold) in the bronchoalveolar lavage of WT mice. After 3 months, CS induced a prominent pulmonary inflammatory cell influx in WT and TNF-alpha R1 KO mice. In TNF-alpha R2 KO mice, CS-induced pulmonary inflammation was clearly attenuated. After 6 months, no emphysema was observed in CS-exposed TNF-alpha R2 KO mice in contrast to WT and TNF-alpha R1 KO mice. CS-exposed WT and TNF-alpha R1 KO mice failed to gain weight, whereas the body mass of TNF-alpha R2 KO mice was not affected. These current findings suggest that both tumour necrosis factor-alpha receptors contribute to the pathogenesis of chronic obstructive pulmonary disease, but tumour necrosis factor-alpha receptor-2 is the most active receptor in the development of inflammation, emphysema and systemic weight loss in this murine model of chronic obstructive pulmonary disease.

Inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease. In the present study a murine model of tobacco smoke-induced emphysema was used to investigate the time course of airway and pulmonary inflammatory response, with a special emphasis on pulmonary dendritic cell (DC) populations. Groups of mice were exposed to either cigarette smoke or to control air for up to 24 weeks. In response to cigarette smoke, inflammatory cells (i.e. neutrophils, macrophages and lymphocytes) progressively accumulated both in the airways and lung parenchyma of mice. Furthermore, a clear infiltration of DCs was observed in airways (10-fold increase) and lung parenchyma (1.5-fold increase) of cigarette-exposed mice at 24 weeks. Flow cytometric analysis of bronchoalveolar lavage (BAL) DCs of smoke-exposed mice showed upregulation of major histocompatability complex II molecules and costimulatory molecules CD40 and CD86, compared with BAL DCs of air-exposed mice. Morphometric analysis of lung histology demonstrated a significant increase in mean linear intercept and alveolar wall destruction after 24 weeks of smoke exposure. In conclusion, the time course of the changes in inflammatory and dendritic cells in both bronchoalveolar lavage and the pulmonary compartment of cigarette smoke-exposed mice was carefully characterised.