European Position Paper on Rhinosinusitis and Nasal Polyps 2020.

The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 is the update of similar evidence based position papers published in 2005 and 2007 and 2012. The core objective of the EPOS2020 guideline is to provide revised, up-to-date and clear evidence-based recommendations and integrated care pathways in ARS and CRS. EPOS2020 provides an update on the literature published and studies undertaken in the eight years since the EPOS2012 position paper was published and addresses areas not extensively covered in EPOS2012 such as paediatric CRS and sinus surgery. EPOS2020 also involves new stakeholders, including pharmacists and patients, and addresses new target users who have become more involved in the management and treatment of rhinosinusitis since the publication of the last EPOS document, including pharmacists, nurses, specialised care givers and indeed patients themselves, who employ increasing self-management of their condition using over the counter treatments. The document provides suggestions for future research in this area and offers updated guidance for definitions and outcome measurements in research in different settings. EPOS2020 contains chapters on definitions and classification where we have defined a large number of terms and indicated preferred terms. A new classification of CRS into primary and secondary CRS and further division into localized and diffuse disease, based on anatomic distribution is proposed. There are extensive chapters on epidemiology and predisposing factors, inflammatory mechanisms, (differential) diagnosis of facial pain, allergic rhinitis, genetics, cystic fibrosis, aspirin exacerbated respiratory disease, immunodeficiencies, allergic fungal rhinosinusitis and the relationship between upper and lower airways. The chapters on paediatric acute and chronic rhinosinusitis are totally rewritten. All available evidence for the management of acute rhinosinusitis and chronic rhinosinusitis with or without nasal polyps in adults and children is systematically reviewed and integrated care pathways based on the evidence are proposed. Despite considerable increases in the amount of quality publications in recent years, a large number of practical clinical questions remain. It was agreed that the best way to address these was to conduct a Delphi exercise . The results have been integrated into the respective sections. Last but not least, advice for patients and pharmacists and a new list of research needs are included. The full document can be downloaded for free on the website of this journal: http://www.rhinologyjournal.com.

The role of miR-155 in cigarette smoke-induced pulmonary inflammation and COPD.

Chronic obstructive pulmonary disease (COPD) is a highly prevalent respiratory disease characterized by airflow limitation and chronic inflammation. MiR-155 is described as an ancient regulator of the immune system. Our objective was to establish a role for miR-155 in cigarette smoke (CS)-induced inflammation and COPD. We demonstrate increased miR-155 expression by RT-qPCR in lung tissue of smokers without airflow limitation and patients with COPD compared to never smokers and in lung tissue and alveolar macrophages of CS-exposed mice compared to air-exposed mice. In addition, we exposed wild type and miR-155 deficient mice to CS and show an attenuated inflammatory profile in the latter. Alveolar macrophages were sorted by FACS from the different experimental groups and their gene expression profile was analyzed by RNA sequencing. This analysis revealed increased expression of miR-155 targets and an attenuation of the CS-induced increase in inflammation-related genes in miR-155 deficient mice. Moreover, intranasal instillation of a specific miR-155 inhibitor attenuated the CS-induced pulmonary inflammation in mice. Finally, elastase-induced emphysema and lung functional changes were significantly attenuated in miR-155 deficient mice. In conclusion, we highlight a role for miR-155 in CS-induced inflammation and the pathogenesis of COPD, implicating miR-155 as a new therapeutic target in COPD.

Bone morphogenetic protein 6 (BMP-6) modulates lung function, pulmonary iron levels and cigarette smoke-induced inflammation.

Chronic obstructive pulmonary disease (COPD) is associated with abnormal inflammatory responses and airway wall remodeling, leading to reduced lung function. An association between the bone morphogenetic protein (BMP-6) locus and forced vital capacity has been found in a genome-wide association study. However, the role of BMP-6 in the pathogenesis of COPD remains unknown. The pulmonary expression of BMP-6 was analyzed in patients with COPD and in cigarette smoke (CS)-exposed mice. We evaluated lung function and histology in BMP-6 KO mice at baseline. We exposed BMP-6 KO mice to CS for 4 weeks and measured pulmonary inflammation and iron levels. Pulmonary mRNA levels of BMP-6 were decreased in smokers with and without COPD and in CS-exposed mice. Importantly, BMP-6 expression was lowest in severe COPD. Accordingly, protein levels of BMP-6 were decreased in patients with COPD. Lung function measurements demonstrated a decreased compliance and total lung capacity in BMP-6 KO mice, whereas lung histology was normal. Furthermore, BMP-6 KO mice displayed elevated iron levels and an aggravated CS-induced inflammatory response. These results suggest that BMP-6 is important for normal lung function and that downregulation of BMP-6-as observed in patients with COPD-contributes to pulmonary inflammation after CS exposure.

Elevated GDF-15 contributes to pulmonary inflammation upon cigarette smoke exposure.

The molecular mechanisms underlying the pathogenesis of chronic obstructive pulmonary disease (COPD) are still unclear, however signaling pathways associated with lung development, such as the transforming growth factor (TGF)-ß superfamily, could be implicated in COPD. Growth differentiation factor (GDF)-15, a member of the TGF-ß superfamily, is involved in inflammation, mucus secretion, and cachexia. We analyzed the pulmonary expression of GDF-15 in smokers and patients with COPD, in cigarette smoke (CS)-exposed cultures of primary human bronchial epithelial cells (pHBECs), and in CS-exposed mice. Next, we exposed GDF-15 KO and control mice to air or CS and evaluated pulmonary inflammation. GDF-15 levels were higher in sputum supernatant and lung tissue of patients with COPD and smokers without COPD compared with never smokers. Immunohistochemistry revealed GDF-15 staining in the airway epithelium. Increased expression and secretion of GDF-15 was confirmed in vitro in CS-exposed pHBECs compared with air-exposed pHBECs. Similarly, GDF-15 levels were increased in lungs of CS-exposed mice. Importantly, GDF-15 deficiency attenuated the CS-induced pulmonary inflammation. These results suggest that increased GDF-15-as observed in lungs of smokers and patients with COPD-contributes to CS-induced pulmonary inflammation.

A rare cause of haemoptysis.

A 59-year-old man was admitted with haemoptysis, several months after a car accident. A diagnostic work-up including laboratory testing, chest radiograph and bronchoscopy could not explain the haemoptysis. A pancreatic-pulmonary fistula was suspected by additional CT scan. Magnetic resonance cholangiopancreaticography confirmed the diagnosis, followed by surgical exploration and repair.

COPD is associated with reduced pulmonary interstitial expression of pentraxin-3.

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.

Role of IL-1α and the Nlrp3/caspase-1/IL-1ß axis in cigarette smoke-induced pulmonary inflammation and COPD.

Cigarette smoke (CS), the primary risk factor of chronic obstructive pulmonary disease (COPD), leads to pulmonary inflammation through interleukin-1 receptor (IL-1R)I signalling, as determined using COPD mouse models. It is unclear whether interleukin (IL)-1α or IL-1ß, activated by the Nlrp3/caspase-1 axis, is the predominant ligand for IL-1RI in CS-induced responses. We exposed wild-type mice (treated with anti-IL-1α or anti-IL-1ß antibodies), and IL-1RI knockout (KO), Nlrp3 KO and caspase-1 KO mice to CS for 3 days or 4 weeks and evaluated pulmonary inflammation. Additionally, we measured the levels of IL-1α and IL-1ß mRNA (in total lung tissue by RT-PCR) and protein (in induced sputum by ELISA) of never-smokers, smokers without COPD and patients with COPD. In CS-exposed mice, pulmonary inflammation was dependent on IL-1RI and could be significantly attenuated by neutralising IL-1α or IL-1ß. Interestingly, CS-induced inflammation occurred independently of IL-1ß activation by the Nlrp3/caspase-1 axis. In human subjects, IL-1α and IL-1ß were significantly increased in total lung tissue and induced sputum of patients with COPD, respectively, compared with never-smokers. These results suggest that not only IL-1ß but also IL-1α should be considered as an important mediator in CS-induced inflammation and COPD.

Plasmacytoid dendritic cells in pulmonary lymphoid follicles of patients with COPD.

Plasmacytoid dendritic cells (pDCs) are professional antigen-presenting cells with antiviral and tolerogenic capabilities. Viral infections and autoimmunity are proposed to be important mechanisms in the pathogenesis of chronic obstructive pulmonary disease (COPD). The study aimed to quantify blood dendritic cell antigen 2-positive pDCs in lungs of subjects with or without COPD by immunohistochemistry and flow cytometry, combined with the investigation of the influence of cigarette smoke extract (CSE) on the function of pDCs in vitro. pDCs were mainly located in lymphoid follicles, a finding compatible with their expression of lymphoid homing chemokine receptors CXCR3 and CXCR4. pDC accumulated in the lymphoid follicles and in lung digests of patients with mild to moderate COPD, compared with smokers without airflow limitation and patients with COPD Global Initiative for Chronic Obstructive Lung disease (GOLD) stage III-IV. Exposing maturing pDC of healthy subjects to CSE in vitro revealed an attenuation of the expression of co-stimulatory molecules and impaired interferon-α production. Maturing pDC from patients with COPD produced higher levels of tumour necrosis factor (TNF)-α and interleukin (IL)-8 compared to pDC from healthy subjects. CSE significantly impairs the antiviral function of pDCs. In COPD, a GOLD stage dependent accumulation of pDC in lymphoid follicles is present, combined with an enhanced production of TNF-α and IL-8 by maturing pDCs.

Hedgehog-interacting protein is a COPD susceptibility gene: the Rotterdam Study.

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.

Between a cough and a wheeze: dendritic cells at the nexus of tobacco smoke-induced allergic airway sensitization.

Exposure to cigarette smoke represents a major risk factor for the development of asthma. Enhanced sensitization toward allergens has been observed in humans and laboratory animals exposed to cigarette smoke. Pulmonary dendritic cells (DCs) are crucially involved in sensitization toward allergens and play an important role in the development of T helper (Th)2-mediated allergic airway inflammation. We propose the concept that aberrant DC activation forms the basis for the deviation of the lung's default tolerogenic response toward allergic inflammation when harmless antigens are concomittantly inhaled with tobacco smoke. This review will summarize evidence suggesting that tobacco smoke can achieve this effect by providing numerous triggers of innate immunity, which can profoundly modulate airway DC biology. Tobacco smoke can affect the airway DC network either directly or indirectly by causing the release of DC-targeted mediators from the pulmonary tissue environment, resulting in the induction of a Th2-oriented pathological immune response. A thorough knowledge of the molecular pathways involved may open the door to novel approaches in the treatment of asthma.

Role of lymphotoxin-alpha in cigarette smoke-induced inflammation and lymphoid neogenesis.

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.

Effects of ciclesonide and fluticasone on cortisol secretion in patients with persistent asthma.

We compared the systemic and clinical effects of ciclesonide (CIC) and fluticasone propionate (FP) administered, in addition to CIC 160 microg x day(-1) and salmeterol 50 microg twice daily, in 32 patients with persistent asthma using a randomised double-blind, placebo-controlled, double-dummy, five-period crossover design. All patients exhibited a provocative concentration leading to a 20% decrease in forced expiratory volume in 1 s (PC(20)) methacholine <8 mg x mL(-1) and a PC(20) adenosine <60 mg x mL(-1). Primary outcome was 24-h serum cortisol suppression after 7 days. Secondary outcomes were changes in PC(20) methacholine and adenosine after 9 days. FP 500 microg x day(-1) and 1,000 microg x day(-1) significantly suppressed cortisol secretion versus placebo by -46.2 (95% confidence interval (CI) -83.8- -8.5) nmol x L(-1) and by -76.1 (95% CI -112.9- -39.3) nmol x L(-1), respectively. Neither dose of CIC (320 nor 640 microg x day(-1)) had a significant suppressive effect (-28.2 (95% CI -65.5-9.2) nmol x L(-1) and -37.3 (95% CI -74.7-0.0) nmol x L(-1), respectively). Differences between FP 1,000 microg x day(-1) and both CIC treatments were statistically significant (CIC 320 microg x day(-1): -48.0 (95% CI -84.8- -11.1) nmol x L(-1); CIC 640 microg x day(-1): -38.8 (95% CI -75.7- -1.9) nmol x L(-1)). Compared with placebo, the increase in PC(20) adenosine after the four treatments was small, but significant. Greater improvements in PC(20) adenosine were seen with FP 500 microg x day(-1) (1.8 (95% CI 1.0-2.6) doubling concentrations) compared with CIC 320 microg x day(-1) (0.9 (95% CI 0.1-1.7) doubling concentrations). No significant difference was seen between CIC 640 microg x day(-1) and FP 1,000 microg x day(-1). For a similar decrease in hyperresponsiveness, cortisol secretion was suppressed significantly with moderate-to-high doses of fluticasone propionate, but not with ciclesonide.

Cigarette smoke-induced pulmonary inflammation, but not airway remodelling, is attenuated in chemokine receptor 5-deficient mice.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by a chronic inflammatory response of the airways and lungs to noxious particles and gases, mostly cigarette smoke (CS). Pathological changes characteristic of COPD include airway wall thickening, peribronchial fibrosis, peribronchial lymphoid follicles and destruction of lung parenchyma (emphysema). The recruitment of inflammatory cells into the lung in response to CS is thought to play an important role in the development of COPD. OBJECTIVE: Our aim was to study the contribution of chemokine receptor 5 (CCR5) to the pathogenesis of COPD and specifically whether the development of airway remodelling is a direct result of airway inflammation or rather occurs through an independent mechanism. METHODS: In this study, C57BL/6 wild-type mice and CCR5-deficient mice were subjected to sub-acute (4 weeks) and chronic (24 weeks) CS exposure. RESULTS: Both sub-acute and chronic CS exposure significantly increased CCR5 mRNA expression and protein levels of CCR5 ligands [macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta and regulated upon activation, normal T expressed and secreted (RANTES)], and induced the recruitment of neutrophils, macrophages, dendritic cells, and lymphocytes to the bronchoalveolar lavage (BAL) of wild-type mice. Chronic CS exposure also increased the number and extent of peribronchial lymphoid follicles. In CCR5 knockout (KO) mice, these CS-induced increases in CCR5 ligands, inflammatory cells in BAL and peribronchial lymphoid follicles were all significantly attenuated compared with wild-type animals. Importantly, chronic CS exposure induced airspace enlargement in wild-type mice, while CCR5 KO mice were partially protected against the development of emphysema. However, CCR5 deficiency did not affect CS-induced airway wall remodelling, because chronic CS exposure induced a similar increase in airway wall thickness, smooth muscle mass and peribronchial deposition of collagen and fibronectin in both wild-type and CCR5 KO mice. CONCLUSION: Our data suggest that CCR5 contributes to pulmonary inflammation and to the development of emphysema in response to CS. CCR5 is, however, not implicated in CS-induced airway wall remodelling, suggesting that the mechanisms that lead to airway inflammation are distinct to those responsible for airway remodelling.

Role of tumour necrosis factor-alpha receptor p75 in cigarette smoke-induced pulmonary inflammation and emphysema.

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.

Animal models of allergen-induced tolerance in asthma: are T-regulatory-1 cells (Tr-1) the solution for T-helper-2 cells (Th-2) in asthma?

Non-specific anti-inflammatory medication is actually the treatment of choice for controlling the T-helper type 2 (Th-2) cell-driven airway inflammation in asthma. The induction of counterbalancing Th-1 cell clones, long considered a promising approach for immunotherapy, has failed to fulfil its promise because of potentially detrimental side-effects. This is therefore probably not a valid option for the treatment of asthma. With the increasing awareness that active immune mechanisms exist to control inflammatory responses, interest rises to investigate whether these can be exploited to control allergen-induced airway disease. The induction of antigen-specific T cells with suppressive characteristics (regulatory T cells) is therefore a potentially interesting approach. These regulatory T cells mediate tolerance in healthy, non-atopic individuals and have the potential of becoming an effective means of preventing allergen-induced airway inflammation and possibly of suppressing ongoing allergic immune responses. Here we review the available knowledge about allergen-induced suppressive immunity obtained from animal models taking into account the different developmental stages of allergic airway disease.

Murine models of COPD.

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, that is not fully reversible, and that is associated with an abnormal inflammatory response of the airways and lungs to noxious particles and gases. The airflow limitation is caused by increased resistance of the small conducting airways and by decreased elastic recoil forces of the lung due to emphysematous destruction of the lung parenchyma. In vivo animal models can help to unravel the molecular and cellular mechanisms underlying the pathogenesis of COPD. Mice represent the most favored animal species with regard to the study of (both innate and adaptive) immune mechanisms, since they offer the opportunity to manipulate gene expression. Several experimental approaches are applied in order to mimic the different traits of COPD in these murine models. Firstly, the tracheal instillation of tissue-degrading enzymes induces emphysema-like lesions in the lung parenchyma, adding further proof to the protease-antiprotease imbalance hypothesis. Secondly, the inhalation of noxious stimuli, including tobacco smoke, sulfur dioxide, nitrogen dioxide, or oxidants such as ozone, may also lead to COPD-like lesions in mice, depending on concentration, duration of exposure and strainspecific genetic susceptibility. Thirdly, in transgenic mice, a specific gene is either overexpressed (non-specific or organ-specific) or selectively depleted (constitutively or conditionally). The study of these transgenic mice, either per se or in combination with the above mentioned experimental approaches (e.g. the inhalation of tobacco smoke), can offer valuable information on both the physiological function of the gene of interest as well as the pathophysiological mechanisms of diseases with complex traits such as COPD.

Elevated MMP-12 protein levels in induced sputum from patients with COPD.

BACKGROUND: Several matrix metalloproteinases (MMPs) are involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). In mice, MMP-12 plays a crucial role in the development of cigarette smoke induced emphysema. A study was undertaken to investigate the role of MMP-12 in the development of COPD in human smokers. METHODS: Induced sputum samples were collected from patients with stable COPD (n = 28), healthy smokers (n = 14), never smokers (n = 20), and former smokers (n = 14). MMP-12 protein levels in induced sputum were determined by ELISA and compared between the four study groups. MMP-12 enzymatic activity in induced sputum was evaluated by casein zymography and by cleaving of a fluorescence quenched substrate. RESULTS: Median (IQR) MMP-12 levels were significantly higher in COPD patients than in healthy smokers, never smokers, and former smokers (17.5 (7.1-42.1) v 6.7 (3.9-10.4) v 4.2 (2.4-11.3) v 6.1 (4.5-7.6) ng/ml, p = 0.0002). MMP-12 enzymatic activity was significantly higher in patients with COPD than in controls (4.11 (1.4-8.0) v 0.14 (0.1-0.2) microg/microl, p = 0.0002). CONCLUSION: MMP-12 is markedly increased in induced sputum from patients with stable COPD compared with controls, suggesting a role for MMP-12 in the development of COPD in smokers.

[Indirect bronchial provocation tests: a new, specific group of bronchial provocation tests for asthma]. / Indirecte bronchiale provocatietests: een nieuwe, specifieke groep van bronchiale provocatietests voor astma.

Asthma is characterized by a variable airway obstruction, bronchial hyperresponsiveness and airway inflammation. Usually, bronchial hyperresponsiveness is measured in the clinic by provocation with non specific stimuli such as histamine or methacholine. These stimuli are called direct, as they constrict the airways by a direct stimulation of airway smooth muscle. Pharmacological stimuli such as adenosine, tachykinins and bradykinin, and physical stimuli such as exercise, isocapnic hyperventilation or hypertonic saline, are called indirect stimuli: they stimulate inflammatory cells and/or neuronal cells and the released mediator and/or neurotransmitter causes the airways to narrow. In the past 10 years the mechanisms and receptors involved in the airway narrowing caused by these indirect bronchial challenges have been characterized. It has become clear that indirect challenges form a specific group of challenges that play a role in the diagnosis and the monitoring of asthma.

Time course of cigarette smoke-induced pulmonary inflammation in mice.

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.