NOX enzymes: potential target for the treatment of acute lung injury

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS), is characterized by acute inflammation, disruption of the alveolar-capillary barrier, and in the organizing stage by alveolar pneumocytes hyperplasia and extensive lung fibrosis. The cellular and molecular mechanisms leading to the development of ALI/ARDS are not completely understood, but there is evidence that reactive oxygen species (ROS) generated by inflammatory cells as well as epithelial and endothelial cells are responsible for inflammatory response, lung damage, and abnormal repair. Among all ROS-producing enzymes, the members of NADPH oxidases (NOXs), which are widely expressed in different lung cell types, have been shown to participate in cellular processes involved in the maintenance of lung integrity. It is not surprising that change in NOXs' expression and function is involved in the development of ALI/ARDS. In this context, the use of NOX inhibitors could be a possible therapeutic perspective in the management of this syndrome. In this article, we summarize the current knowledge concerning some cellular aspects of NOXs localization and function in the lungs, consider their contribution in the development of ALI/ARDS and discuss the place of NOX inhibitors as potential therapeutical targe

Effects of volatile anaesthetic agents on enhanced airway tone in sensitized guinea pigs

Background. Although volatile anaesthetics afford protection against bronchospasm, their potential to reverse a sustained constriction of hyperreactive airways has not been characterized. Accordingly, we investigated the ability of halothane, isoflurane, sevoflurane and desflurane to reverse lung constriction induced by prolonged stimulation of the muscarinic receptors in guinea pigs sensitized to ovalbumin. Methods. Pulmonary input impedance (ZL) was measured using forced oscillations in five groups of ovalbumin‐sensitized, mechanically ventilated guinea pigs. ZL was measured under baseline conditions, during steady‐state bronchoconstriction induced by an i.v. infusion of methacholine (MCh), and after administration of one of the volatile agents at 1 MAC after the induction of a steady‐state bronchoconstriction. Airway resistance (Raw), and parenchymal tissue resistive and elastic coefficients were extracted from ZL by model fitting. Results. All four volatile agents exhibited an initial relaxation of the MCh‐induced airway constriction followed by gradual increases in Raw. The bronchodilatory effect of isoflurane was the most potent (-28.9 (se 5.5)% at 2 min, P<0.05) and lasted longest (7 min); sevoflurane and halothane had shorter and more moderate effects (-21.1 (3.9)%, P<0.05, and -6.1 (1.7)%, P<0.05, respectively, at 1 min). Desflurane caused highly variable changes in Raw, with a tendency to enhance airway tone. Conclusions. Volatile agents can reverse sustained MCh‐induced airway constriction only transiently in sensitized guinea pigs. Isoflurane proved most beneficial in temporally improving lung function in the presence of a severe constriction of allergic inflamed airways. Desflurane displayed potential to induce further airway constriction. Br J Anaesth 2004; 92: 254-6

Bird breeder's disease: a rare diagnosis in young children

Bird breeder's lung disease is the most common form of hypersensitivity pneumonitis and is a rare entity in young children. We report three cases of children under 7 years of age in whom this diagnosis was confirmed early in the course of the disease. Three children aged 4.4 to 6.5 years presented with dry cough lasting for more than 1 month, dyspnoea, variable loss of appetite, weight loss, fatigue, fever and mild signs of respiratory distress. Chest X-ray films and CT scans showed a bilateral micronodular infiltrate. All three patients had strongly suggestive bronchoalveolar lavage fluid findings with lymphocytosis; two had elevated cell counts and decreased CD4/CD8 ratios. Lung biopsy confirmed the diagnosis in all children. Contact with allergens was identified in all children: two had spent holidays close to a farm in the previous month and one was living next to a pigeon house. In all children, avian precipitins were positive. The symptoms rapidly resolved after allergen avoidance and treatment with oral prednisone. Corticoid treatment was given between 11 and 15 weeks. One child relapsed and required long-term low-dose corticotherapy for 1 year. Lung function tests were normal in all three patients, 3.9 to 5.7 years after diagnosis. Conclusion:Bird breeder's lung disease is a rare entity but should be considered in young children presenting long lasting cough. While rapid allergen exclusion and start of treatment can avoid the evolution into irreversible lung fibrosis, clinical and biological evolution should be monitored carefully even after stopping corticoid treatment because of the possibility of relaps

Chest physiotherapy using passive expiratory techniques does not reduce bronchiolitis severity: a randomised controlled trial

Chest physiotherapy (CP) using passive expiratory manoeuvres is widely used in Western Europe for the treatment of bronchiolitis, despite lacking evidence for its efficacy. We undertook an open randomised trial to evaluate the effectiveness of CP in infants hospitalised for bronchiolitis by comparing the time to clinical stability, the daily improvement of a severity score and the occurrence of complications between patients with and without CP. Children <1year admitted for bronchiolitis in a tertiary hospital during two consecutive respiratory syncytial virus seasons were randomised to group 1 with CP (prolonged slow expiratory technique, slow accelerated expiratory flow, rarely induced cough) or group 2 without CP. All children received standard care (rhinopharyngeal suctioning, minimal handling, oxygen for saturation ≥92%, fractionated meals). Ninety-nine eligible children (mean age, 3.9months), 50 in group 1 and 49 in group 2, with similar baseline variables and clinical severity at admission. Time to clinical stability, assessed as primary outcome, was similar for both groups (2.9 ± 2.1 vs. 3.2 ± 2.8days, P = 0.45). The rate of improvement of a clinical and respiratory score, defined as secondary outcome, only showed a slightly faster improvement of the respiratory score in the intervention group when including stethoacoustic properties (P = 0.044). Complications were rare but occurred more frequently, although not significantly (P = 0.21), in the control arm. In conclusion, this study shows the absence of effectiveness of CP using passive expiratory techniques in infants hospitalised for bronchiolitis. It seems justified to recommend against the routine use of CP in these patient

Erratum to: Chest physiotherapy using passive expiratory techniques does not reduce bronchiolitis severity: a randomised controlled trial

Chest physiotherapy (CP) using passive expiratory manoeuvres is widely used in Western Europe for the treatment of bronchiolitis, despite lacking evidence for its efficacy. We undertook an open randomised trial to evaluate the effectiveness of CP in infants hospitalised for bronchiolitis by comparing the time to clinical stability, the daily improvement of a severity score and the occurrence of complications between patients with and without CP. Children <1year admitted for bronchiolitis in a tertiary hospital during two consecutive respiratory syncytial virus seasons were randomised to group 1 with CP (prolonged slow expiratory technique, slow accelerated expiratory flow, rarely induced cough) or group 2 without CP. All children received standard care (rhinopharyngeal suctioning, minimal handling, oxygen for saturation ≥92%, fractionated meals). Ninety-nine eligible children (mean age, 3.9months), 50 in group 1 and 49 in group 2, with similar baseline variables and clinical severity at admission. Time to clinical stability, assessed as primary outcome, was similar for both groups (2.9 ± 2.1 vs. 3.2 ± 2.8days, P = 0.45). The rate of improvement of a clinical and respiratory score, defined as secondary outcome, only showed a slightly faster improvement of the respiratory score in the intervention group when including stethoacoustic properties (P = 0.044). Complications were rare but occurred more frequently, although not significantly (P = 0.21), in the control arm. In conclusion, this study shows the absence of effectiveness of CP using passive expiratory techniques in infants hospitalised for bronchiolitis. It seems justified to recommend against the routine use of CP in these patient

CD4+CD25−mTGFβ+ T cells induced by nasal application of ovalbumin transfer tolerance in a therapeutic model of asthma

Background: Intranasal administration of high amount of allergen was shown to induce tolerance and to reverse the allergic phenotype. However, mechanisms of tolerance induction via the mucosal route are still unclear. Objectives: To characterize the therapeutic effects of intranasal application of ovalbumin (OVA) in a mouse model of bronchial inflammation as well as the cellular and molecular mechanisms leading to protection upon re-exposure to allergen. Methods: After induction of bronchial inflammation, mice were treated intranasally with OVA and re-exposed to OVA aerosols 10 days later. Bronchoalveolar lavage fluid (BALF), T cell proliferation and cytokine secretion were examined. The respective role of CD4+CD25+ and CD4+CD25− T cells in the induction of tolerance was analysed. Results: Intranasal treatment with OVA drastically reduced inflammatory cell recruitment into BALF and bronchial hyperresponsiveness upon re-exposure to allergen. Both OVA- specific-proliferation of T cells, Th1 and Th2 cytokine production from lung and bronchial lymph nodes were inhibited. Transfer of CD4+CD25− T cells, which strongly expressed membrane-bound transforming growth factor β (mTGFβ), from tolerized mice protected asthmatic recipient mice from subsequent aerosol challenges. The presence of CD4+CD25+(Foxp3+) T cells during the process of tolerization was indispensable to CD4+CD25− T cells to acquire regulatory properties. Whereas the presence of IL-10 appeared dispensable in this model, the suppression of CD4+CD25−mTGFβ+ T cells in transfer experiments significantly impaired the down-regulation of airways inflammation. Conclusion: Nasal application of OVA in established asthma led to the induction of CD4+CD25−mTGFβ+ T cells with regulatory properties, able to confer protection upon allergen re-exposur

Comparison of clinical presentation of respiratory tract infections in H1N1/09-positive and H1N1/09-negative patients

The true burden of influenza in children is difficult to assess and is probably underestimated as clinical signs are usually nonspecific, and formal viral identification is rarely searched. In this study, we compare the clinical features of infections related to the new H1N1/09 influenza virus with infections due to other respiratory viruses in children consulting in a tertiary care pediatric hospital in Geneva. Between October 1, 2009 and February 10, 2010, 109 patients were recruited, with a median of age of 7years (range 0.1-18). There were 75 H1N1/09-positive patients (69%), and 32 (43%) had identified risk factors such as asthma or a history of wheezing. Fever (87%), cough (92%), and rhinitis (85%) were the most frequent reported presenting symptoms in both patient groups. H1N1/09-positive patients were significantly older (median of 8.2 vs. 4.6years) and were more likely to have risk factors (43% vs. 24%) and myalgias (41% vs. 20%). H1N1/09-negative patients had more wheezing episodes (29% vs. 9%), higher rates of dyspnea (28% vs. 20%) and of hospital admissions (35% vs. 16%). Conclusion: Clinical signs cannot reliably differentiate H1N1/09-positive and H1N1/09-negative patients, although we found a higher proportion of myalgias in H1N1/09-positive patients. Severity of disease was lower in H1N1/09-positive than in H1N1/09-negative patients, mostly because of a higher proportion of asthma/wheezing episodes among H1N1/09-negative patient

BARD1 mediates TGF-β signaling in pulmonary fibrosis

Background Idiopathic pulmonary fibrosis (IPF) is a rapid progressive fibro-proliferative disorder with poor prognosis similar to lung cancer. The pathogenesis of IPF is uncertain, but loss of epithelial cells and fibroblast proliferation are thought to be central processes. Previous reports have shown that BARD1 expression is upregulated in response to hypoxia and associated with TGF-β signaling, both recognized factors driving lung fibrosis. Differentially spliced BARD1 isoforms, in particular BARD1β, are oncogenic drivers of proliferation in cancers of various origins. We therefore hypothesized that BARD1 and/or its isoforms might play a role in lung fibrosis. Methods We investigated BARD1 expression as a function of TGF-β in cultured cells, in mice with experimentally induced lung fibrosis, and in lung biopsies from pulmonary fibrosis patients. Results FL BARD1 and BARD1β were upregulated in response to TGF-β in epithelial cells and fibroblasts in vitro and in vivo. Protein and mRNA expression studies showed very low expression in healthy lung tissues, but upregulated expression of full length (FL) BARD1 and BARD1β in fibrotic tissues. Conclusion Our data suggest that FL BARD1 and BARD1β might be mediators of pleiotropic effects of TGF-β. In particular BARD1β might be a driver of proliferation and of pulmonary fibrosis pathogenesis and progression and represent a target for treatment