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Summary: Background: Epidemics of asthma and overweight have been linked recently. They might be associated with systemic inflammation. In asthma hyperresponsiveness to adenosine (AMP) is more closely related to inflammation than to methacholine (MCh). The aim of the study was to determine responsiveness to AMP and MCh in overweight compared with normal weight asthmatics. Methods: Thirty women were enrolled (19 overweight) with mild controlled asthma according to GINA. A Body Mass Index (BMI) less than 25kg/m2 was considered as normal and a BMI above 25kg/m2 as overweight. We assessed the recent control of asthma (ACQ), pulmonary function tests, bronchial responsiveness to MCh and AMP (PC20 and O''Connor two-point dose–response slope), perception of symptoms (Borg scale), and blood inflammatory markers (leptin and hs-CRP by ELISA). Results: Overweight had a significant lower dose-response slope of the MCh challenge (p =0.009) as compared to normal weight patients, whereas no significant difference was observed for AMP challenge (p =0.27). Overweight patients had higher intercepts of the Borg scale measured before the MCh and AMP challenge tests (p =0.01 and p =0.03). Plasma leptin (p =0.001) and hs-CRP (p =0.05) concentrations were higher in overweight than normal weight patients. There was no correlation between challenges and inflammatory markers. Conclusions: Overweight asthmatic women have more pronounced systemic inflammation, but are less responsive to MCh. AMP responsiveness appeared to be comparable between both groups. Our findings suggest that overweight asthmatic women do not feature increased airway inflammation, but do represent a distinct phenotype as compared to normal weight patients. [Copyright &y& Elsevier]

Abstract: In this study, we investigated the synthesis of lipoxins (LXs) and their anti-inflammatory effects in different human airway epithelial cell culture models. After cell incubation with exogenous 5(S),6(R)-dihydroxy-7,9-trans-11,14-cis-eicosatetraenoic acid, LXA4 was detected in supernatants of differentiated human bronchial epithelial cells by contrast to non-differentiated cells. Exogenous LXA4 significantly inhibited tumor necrosis factor-α (TNF-α)-induced interleukin-8 (IL-8) release in the different epithelial cell types and the potency of inhibition was dependent of the accessibility of the specific LXA4 receptor, formyl-peptide receptor like-1 (FPRL-1) expressed by all these cells. Immunohistochemistry analysis on human bronchial biopsies showed a high expression of FPRL-1 in the epithelium. Finally, an FPRL-1 receptor antagonist, boc-2 peptide reversed LXA4 effect on IL-8 generation. Together, these findings indicate that differentiated human bronchial epithelium synthesizes LX in vivo which could have autocrine actions through its specific receptor FPRL-1 to promote resolution of airway inflammation. [Copyright &y& Elsevier]

Background: Structural changes to the airways are features of severe asthma. The bronchial epithelium facilitates this remodeling process. Learning about the changes that develop in the airway epithelium could improve our understanding of asthma pathogenesis and lead to new therapeutic approaches. Objective: We sought to determine the feasibility and relevance of air-liquid interface cultures of bronchial epithelium derived from endobronchial biopsy specimens of patients with different severities of asthma for studying the airway epithelium. Methods: Human bronchial epithelial cells derived from endobronchial biopsy specimens of patients with mild and severe asthma were maintained in culture for 21 days in an air-liquid interface to reproduce a fully differentiated airway epithelium. Initially, features of remodeling that included epithelial and subepithelial layers, as well as mucus production, were assessed in paraffin-embedded endobronchial biopsy specimens to evaluate morphologic characteristics of asthmatic patients’ epithelia. Ex vivo differentiated epithelia were then analyzed for morphology and function based on ultrastructural analysis, IL-8 release, lipoxin A4 generation, mucin production, and lipoxygenase gene expression. Results: Morphologic and inflammatory imbalances initially observed in endobronchial biopsy specimens obtained from patients with severe or mild asthma persisted in the air-liquid interface reconstituted epithelium throughout the differentiation process to 21 days. Epithelium from patients with severe asthma produced greater levels of mucin, released more IL-8, and produced lower levels of lipoxin A4 than that from patients with mild asthma. Expression of 15-lipoxygenase 2 was increased in epithelium from patients with severe asthma, whereas expression levels of MUC5AC, MUC5B, 5-lipoxygenase, and 15-lipoxygeanse 1 were similar to those of patients with mild asthma. Conclusion: Ex vivo cultures of fully differentiated bronchial epithelium from endobronchial biopsy specimens maintain inherent phenotypic differences specifically related to the severity of asthma. [Copyright &y& Elsevier]