BACKGROUND Treatment guidelines recommend the use of inhaled long-acting bronchodilators to alleviate symptoms and reduce the risk of exacerbations in patients with moderate-tovery-severe chronic obstructive pulmonary disease (COPD) but do not specify whether a long-acting anticholinergic drug or a β 2-agonist is the preferred agent. We investigated whether the anticholinergic drug tiotropium is superior to the β 2-agonist salmeterol in preventing exacerbations of COPD. METHODS In a 1-year, randomized, double-blind, double-dummy, parallel-group trial, we compared the effect of treatment with 18 μg of tiotropium once daily with that of 50 μg of salmeterol twice daily on the incidence of moderate or severe exacerbations in patients with moderate-to-very-severe COPD and a history of exacerbations in the preceding year. RESULTS A total of 7376 patients were randomly assigned to and treated with tiotropium (3707 patients) or salmeterol (3669 patients). Tiotropium, as compared with salmeterol, increased the time to the first exacerbation (187 days vs. 145 days), with a 17% reduction in risk (hazard ratio, 0.83; 95% confidence interval [CI], 0.77 to 0.90; P<0.001). Tiotropium also increased the time to the first severe exacerbation (hazard ratio, 0.72; 95% CI, 0.61 to 0.85; P<0.001), reduced the annual number of moderate or severe exacerbations (0.64 vs. 0.72; rate ratio, 0.89; 95% CI, 0.83 to 0.96; P = 0.002), and reduced the annual number of severe exacerbations (0.09 vs. 0.13; rate ratio, 0.73; 95% CI, 0.66 to 0.82; P<0.001). Overall, the incidence of serious adverse events and of adverse events leading to the discontinuation of treatment was similar in the two study groups. There were 64 deaths (1.7%) in the tiotropium group and 78 (2.1%) in the salmeterol group. CONCLUSIONS These results show that, in patients with moderate-to-very-severe COPD, tiotropium is more effective than salmeterol in preventing exacerbations. (Funded by Boehringer Ingelheim and Pfizer; ClinicalTrials.gov number, NCT00563381.

This study demonstrates that combination therapy with salmeterol/fluticasone compared with salmeterol monotherapy significantly reduces the frequency of moderate/severe exacerbations in patients with severe COPD.

The widespread use of genetically altered mouse models of experimental asthma has stimulated the development of lung function techniques in vivo to characterize the functional results of genetic manipulations. Here, we describe various classical and recent methods of measuring airway responsiveness in vivo including both invasive methodologies in anesthetized, intubated mice (repetitive/non-repetitive assessment of pulmonary resistance (R L ) and dynamic compliance (C dyn ); measurement of low-frequency forced oscillations (LFOT)) and noninvasive technologies in conscious animals (head-out body plethysmography; barometric whole-body plethysmography). Outlined are the technical principles, validation and applications as well as the strengths and weaknesses of each methodology. Reviewed is the current set of invasive and noninvasive methods of measuring murine pulmonary function, with particular emphasis on practical considerations that should be considered when applying them for phenotyping in the laboratory mouse.

Current methods for assessing clinical outcomes in COPD mainly rely on physiological tests combined with the use of questionnaires. The present review considers commonly used outcome measures such as lung function, health status, exercise capacity and physical activity, dyspnoea, exacerbations, the multi-dimensional BODE score, and mortality. Based on current published data, we provide a concise overview of the principles, strengths and weaknesses, and discuss open questions related to each methodology. Reviewed is the current set of markers for measuring clinically relevant outcomes with particular emphasis on their limitations and opportunities that should be recognized when assessing and interpreting their use in clinical trials of COPD.

Airway hyperresponsiveness and airway inflammation are hallmarks of allergic asthma, the etiology of which is crucially linked to the presence of Th2 cytokines. A role for the complement anaphylatoxins C3a and C5a in allergic asthma was suggested, as deficiencies of the C3a receptor (C3aR) and of complement factor C5 modulate airway hyperresponsiveness, airway inflammation, and Th2 cytokine levels. However, such models do not allow differentiation of effects on the sensitization phase and the effector phase of the allergic response, respectively. In this study, we determined the role of the anaphylatoxins on the effector phase of asthma by pharmacological targeting of the anaphylatoxin receptors. C3aR and C5a receptor (C5aR) signaling was blocked using the nonpeptidic C3aR antagonist SB290157 and the neutralizing C5aR mAb 20/70 in a murine model of Aspergillus fumigatus extract induced pulmonary allergy. Airway hyperresponsiveness was substantially improved after C5aR blockade but not after C3aR blockade. Airway inflammation was significantly reduced in mice treated with the C3aR antagonist or the anti-C5aR mAb, as demonstrated by reduced numbers of neutrophils and eosinophils in bronchoalveolar lavage fluid. Of note, C5aR but not C3aR inhibition reduced lymphocyte numbers in bronchoalveolar lavage fluid. Cytokine levels of IL-5 and IL-13 in bronchoalveolar lavage fluid were not altered by C3aR or C5aR blockade. However, blockade of both anaphylatoxin receptors markedly reduced IL-4 levels. These data suggest an important and exclusive role for C5aR signaling on the development of airway hyperresponsiveness during pulmonary allergen challenge, whereas both anaphylatoxins contribute to airway inflammation and IL-4 production.

A method for the noninvasive measurement of airway responsiveness was validated in allergic BALB/c mice. With head-out body plethysmography and the decrease in tidal midexpiratory flow (EF(50)) as an indicator of airway obstruction, responses to inhaled methacholine (MCh) and the allergen ovalbumin were measured in conscious mice. Allergen-sensitized and -challenged mice developed airway hyperresponsiveness as measured by EF(50) to aerosolized MCh compared with that in control animals. This response was associated with increased allergen-specific IgE and IgG1 production, increased levels of interleukin-4 and interleukin-5 in bronchoalveolar lavage fluid and eosinophilic lung inflammation. Ovalbumin aerosol challenge elicited no acute bronchoconstriction but resulted in a significant decline in EF(50) baseline values 24 h after challenge in allergic mice. The decline in EF(50) to MCh challenge correlated closely with simultaneous decreases in pulmonary conductance and dynamic compliance. The decrease in EF(50) was partly inhibited by pretreatment with the inhaled beta(2)-agonist salbutamol. We conclude that measurement of EF(50) to inhaled bronchoconstrictors by head-out body plethysmography is a valid measure of airway hyperresponsiveness in mice.

1 Brain-derived neurotrophic factor (BDNF) is a candidate molecule for mediating functional neuronal changes in allergic bronchial asthma. Recently, enhanced production of BDNF during allergic airway inflammation caused by infiltrating T-cells and macrophages as well as by resident airway epithelial cells has been described. It was the aim of this study to investigate the effect of enhanced BDNF levels on lung function and airway inflammation in a mouse model of allergic inflammation. 2 Ovalbumin-sensitised BALB/c mice were challenged in two consecutive allergen challenges. Prior to the challenge, the mice were treated with either anti-BDNF antibodies or isotype-matched control antibodies. Airway responsiveness to methacholine, capsaicin and electric field stimulation, as well as airway inflammation and chronic airway obstruction 1 week after the last allergen challenge were assessed. 3 Anti-BDNF blocked enhanced reactivity in response to capsaicin, but not airway smooth muscle hyper-reactivity in vivo. Furthermore, persistent airway obstruction, as observed 1 week after the last allergen challenge, was to a large extent prevented by anti-BDNF treatment. In vitro, BDNF and anti-BDNF treatment had a profound effect on local neuronal hyper-reactivity, as shown by electric field stimulation experiments. In contrast, neither BDNF nor anti-BDNF treatment affected airway inflammation. 4 Our data indicate that development of allergen-induced neuronal hyper-reactivity in mice is partially mediated by BDNF.

Background: Mouse models have been established mirroring key features of human bronchial asthma including airway hyperresponsiveness (AHR). Acute airway obstruction in response to an allergen challenge, however, remains to be demonstrated in these models. Objective: A mouse model of allergic lung inflammation was employed to analyze the development of specific (allergen-induced) and nonspecific (methacholine-induced) airway obstruction. Methods: Mice were sensitized to ovalbumin (OVA) and challenged with OVA aerosol twice each week during four weeks. Changes in lung functions were determined by noninvasive head-out body plethysmography. The development of acute airway obstruction after OVA challenge and AHR after methacholine aerosol application were assessed by a decrease in the mid-expiratory flow rate (EF₅₀). Results: Two airway challenges were sufficient to induce AHR (5.7 vs. 15 mg/ml methacholine). Further OVA challenges reduced the baseline EF₅₀ from 1.85 to 1.20 ml/s (4th week) and induced acute airway obstruction. The OVA-induced obstruction was maximal in the 4th week (EF₅₀ = 0.91 ml/s). Conclusion: The development of acute airway obstruction in allergen-sensitized mice was demonstrated by means of head-out body plethysmography. In our model, AHR was observed before the development of airway obstruction.