Cent scientifiques répliquent à SEA (Suppression des Expériences sur l’Animal vivant) et dénoncent sa désinformation

La lutte contre la maltraitance animale est sans conteste une cause moralement juste. Mais elle ne justifie en rien la désinformation à laquelle certaines associations qui s’en réclament ont recours pour remettre en question l’usage de l’expérimentation animale en recherche

PREVALENCE ET FACTEURS DE RISQUE DE SURVENUE DE DYSTHYROIDIES SOUS TRAITEMENT INTERFERON ALPHA AU COURS DE L'HEPATITE CHRONIQUE VIRALE C (ETUDE RETROSPECTIVE DE 126 MALADES NAIFS)

ANGERS-BU Médecine-Pharmacie (490072105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Compression ganglionnaire cholédocienne sur maladie des griffes du chat

ANGERS-BU Médecine-Pharmacie (490072105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

IL-9 inhibits oxidative burst and TNF-alpha release in lipopolysaccharide-stimulated TGF-beta

IL-9 is a Th2 cytokine that exerts pleiotropic activities on T cells, B cells, mast cells, hematopoietic progenitors, and lung epithelial cells, but no effect of this cytokine has been reported so far on mononuclear phagocytes. Human blood monocytes preincubated with IL-9 for 24 h before LPS or PMA stimulation exhibited a decreased oxidative burst, even in the presence of IFN-gamma. The inhibitory effect of IL-9 was specifically abolished by anti-hIL-9R mAb, and the presence of IL-9 receptors was demonstrated on human blood monocytes by FACS. IL-9 also down-regulated TNF-alpha and IL-10 release by LPS-stimulated monocytes. In addition, IL-9 strongly up-regulated the production of TGF-beta1 by LPS-stimulated monocytes. The suppressive effect of IL-9 on the respiratory burst and TNF-alpha production in LPS-stimulated monocytes was significantly inhibited by anti-TGF-beta1, but not by anti-IL-10Rbeta mAb. Furthermore, IL-9 inhibited LPS-induced activation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases in monocytes through a TGF-beta-mediated induction of protein phosphatase activity. In contrast, IL-4, which exerts a similar inhibitory effect on the oxidative burst and TNF-a release by monocytes, acts primarily through a down-regulation of LPS receptors. Thus, IL-9 deactivates LPS-stimulated blood mononuclear phagocytes, and the mechanism of inhibition involves the potentiation of TGF-beta1 production and extracellular signal-regulated kinase inhibition. These findings highlight a new target cell for IL-9 and may account for the beneficial activity of IL-9 in animal models of exaggerated inflammatory response

Oxidative burst in lipopolysaccharide-activated human alveolar macrophages is inhibited by interleukin-9.

Interleukin (IL)-9 is known to regulate many cell types involved in T-helper type 2 responses classically associated with asthma, including B- and T-lymphocytes, mast cells, eosinophils and epithelial cells. In contrast, target cells mediating the effects of IL-9 in the lower respiratory tract remain to be identified. Therefore, the authors evaluated the activity of IL-9 on human alveolar macrophages (AM) from healthy volunteers. AM preincubated with IL-9 before lipopolysaccharide (LPS) stimulation exhibited a decreased oxidative burst, as previously shown with IL-4. The inhibitory effect of IL-9 was abolished by anti-hIL-9R alpha monoclonal antibody, and presence of IL-9 receptors on AM was demonstrated by immunofluorescence. Both IL-4 and IL-9 failed to modulate tumour necrosis factor-alpha, IL-8 and IL-10 release by LPS-stimulated AM. However, several observations suggested that IL-9 and IL-4 act through different mechanisms: 1) interferon-gamma antagonised the IL4- but not the IL-9-mediated inhibition of AM oxidative burst; 2) expression of CD14 was downregulated by IL-4 but not by IL-9 and 3) production of tumour growth factor-beta by activated AM was potentiated by IL-9 and not by IL4, and was required for the IL-9-mediated inhibition of AM oxidative burst. These observations provide additional information concerning the activity of interleukin-9 in the lung, related to inflammatory or fibrosing lung processes

Epithelial to mesenchymal transition in the airway epithelium from copd patients: correlation to disease severity

Rationale: In chronic obstructive pulmonary disease (COPD), epithelial changes and subepithelial fibrosis are salient features in the airways. Epithelial to mesenchymal transition (EMT) has been suggested in COPD, mainly in alveolar epithelial cells. Objectives: To evaluate the presence of EMT in the airways and primary air-liquid interface cultures of bronchial epithelial cells (ALI-HBEC) from COPD patients, as compared to controls. Methods: Surgical lung tissue of COPD and control patients (n=49) and ALI-HBEC cultures (n=57) were assessed for EMT markers by immunohistochemistry, western blot and real-time qPCR. Mesenchymal functionalities of ALI-HBEC were assayed through fibronectin release and wound repair. Measurements and main results: The bronchial epithelium from COPD patients, as compared to non-smokers and smokers without COPD, showed increased vimentin expression in large (p=0.002 for severe COPD versus non-smokers) and small airways correlated with airway obstruction (FEV1, FEV1/VC ratio and DLCO). In addition, epithelial E-cadherin and zonula occludens-1 were decreased in large airways. Increased epithelial vimentin expression correlated to subepithelial deposition and basement membrane thickness in imaging of COPD airway tissue thick slices. In addition, the COPD bronchial epithelium displayed similar features (upregulated vimentin, decreased E-cadherin/ZO-1) in vitro, which were also correlated to lung function. Moreover, COPD ALI-HBEC showed mesenchymal functions such as extra-cellular production of fibronectin and impaired migration during wound repair. Conclusions: The bronchial epithelium from COPD patients displays EMT features in lung tissue, which correlates to disease severity and which are recapitulated in primary cultures in ALI conditions. We propose that this abnormal epithelial programming contributes to peribronchial fibrosis in COPD

Imprinting of the COPD airway epithelium for dedifferentiation and mesenchymal transition.

In chronic obstructive pulmonary disease (COPD), epithelial changes and subepithelial fibrosis are salient features in conducting airways. Epithelial-to-mesenchymal transition (EMT) has been recently suggested in COPD, but the mechanisms and relationship to peribronchial fibrosis remain unclear. We hypothesised that de-differentiation of the COPD respiratory epithelium through EMT could participate in airway fibrosis and thereby, in airway obstruction. Surgical lung tissue and primary broncho-epithelial cultures (in air-liquid interface (ALI)) from 104 patients were assessed for EMT markers. Cell cultures were also assayed for mesenchymal features and for the role of transforming growth factor (TGF)-β1. The bronchial epithelium from COPD patients showed increased vimentin and decreased ZO-1 and E-cadherin expression. Increased vimentin expression correlated with basement membrane thickening and airflow limitation. ALI broncho-epithelial cells from COPD patients also displayed EMT phenotype in up to 2 weeks of culture, were more spindle shaped and released more fibronectin. Targeting TGF-β1 during ALI differentiation prevented vimentin induction and fibronectin release. In COPD, the airway epithelium displays features of de-differentiation towards mesenchymal cells, which correlate with peribronchial fibrosis and airflow limitation, and which are partly due to a TGF-β1-driven epithelial reprogramming