Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
The Société de pneumologie de langue française defines acute exacerbation of chronic obstructive pulmonary disease (AE COPD) as an increase in daily respiratory symptoms, basically duration ≥ 48h or need for treatment adjustment. Etiology of EA COPD are mainly infectious, viral (rhinovirus, influenzae or parainfluenzae virus, coronavirus, adenovirus and respiratory syncytial virus) or bacterial (Haemophilus influenzae, Streptococcus pneumoniae, or Moraxella catarrhalis). Pollutant exposure can also lead to AE COPD, such as NO2, SO2, ozone or particulates (PM10 and PM2.5). In 30% the etiology remains unknown. Differential diagnoses of AE COPD include infectious pneumonia, pneumothorax, acute heart failure and pulmonary embolism. Presences of signs of severity impose hospitalization: signs of respiratory distress, shock, acute confusion but also fragile patients, insufficient home support or absence of response to initial treatment. AE COPD treatments consist on increase in bronchodilators, chest physiotherapy, and antibiotics if sputum is frankly purulent. Systemic corticosteroids should not be systematic.Recommended dose is 0.5 mg/kg on short course (7 days). During hospitalization, oxygen supplementation and thromboprophylaxis could be prescribed. The main interest in noninvasive ventilation is persistent hypercapnia despite optimal medical management. During ambulatory management or hospitalization, clinical assessment at 48-72h is mandatory. L’exacerbation aiguë de bronchopneumopathie chronique obstructive (EA BPCO) représente un événement important dans l’histoire naturelle de la BPCO, notamment en cas d’hospitalisation. Les EA BPCO interviennent dans la gravité et l’évolution de la BPCO ; et leur prévention est un des objectifs principal des traitements de fond.
La Société de pneumologie de langue française définie l’exacerbation aiguë de bronchopneumopathie chronique obstructive (EA BPCO) comme une majoration des symptômes respiratoires au-delà des variations quotidiennes, en pratique, d’une durée ≥ 48h ou justifiant une modification thérapeutique. L’étiologie de ces EA BPCO est principalement infectieuse, virale (rhinovirus, virus influenzae et parainfluenzae, coronavirus, adénovirus et virus respiratoire syncytial) ou bactérienne (principalement Haemophilus influenzae, Streptococcus pneumoniae et Moraxella catarrhalis). Elles peuvent également résulter de l’exposition à certains polluants comme le NO2, le SO2, l’ozone et la pollution particulaire (PM10 et PM2,5). L’étiologie reste indéterminée dans près de 30 % des cas. Les diagnostics différentiels des EA BPCO incluent les pneumopathies infectieuses, les pneumothorax, les poussées d’insuffisance cardiaque et les embolies pulmonaires. La présence de signes de gravité conditionnent l’hospitalisation : signes d’insuffisance respiratoire aiguë, de choc ou de défaillance neurologique, mais aussi en cas de patient fragile, d’absence de soutien familial à domicile ou d’absence de réponse au traitement initial. Le traitement d’une EA BPCO consiste en une majoration des bronchodilatateurs, une kinésithérapie respiratoire, une antibiothérapie en cas d’expectoration franchement purulente.La prescription de corticoïdes systémiques ne doit pas être systématique. La dose recommandée est de 0,5 mg/kg sur une courte période (7 jours). Lors d’une hospitalisation, une oxygénothérapie et une thromboprophylaxie peuvent être prescrite. La ventilation noninvasiveest principalement indiquée en cas de persistance d’une hypercapnie malgré un traitement médical optimal. Que le patient soit pris en charge en ambulatoire ou en hospitalisation, une réévaluation clinique à 48-72h est indispensable.
ISSN: 0755-4982

hal-01117949
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01117949
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01117949/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01117949/file/Prise%20en%20charge%20des%20exacerbations_accepted.pdf
DOI : 10.1016/j.jeurea.2015.02.002

Éditeur(s) : HAL CCSD American Society for Microbiology
Résumé : International audience
Coronaviruses (CoVs) have shown neuroinvasive properties in human and animal secondary to replication in peripheral organ but the mechanism of neuroinvasion is unknown. The major aim of our work was to evaluate the ability of CoVs to enter the central nervous system (CNS) through the blood brain barrier (BBB). Using the high hepatotropic mouse hepatitis virus (MHV) type 3, its attenuated variant 51.6-MHV3, showing low tropism for endothelial cells, and the low hepatotropic MHV-A59 strains from murine coronavirus group, we investigated the viral-induced dysfunctions of BBB in vivo and in brain microvascular endothelial cells (BMECs) in vitro. We report here a MHV strain-specific ability to cross the BBB during acute infection according to their virulence for liver. Brain invasion was only observed in MHV3-infected mice and correlated with enhanced BBB permeability associated with decreased expression of ZO-1, VE-cadherin and occludin but not claudin-5 in the brain or in cultured BMECs. BBB breakdown in MHV3 infection was not related to production of barrier-dysregulating inflammatory cytokines or chemokines by infected BMECs but rather to a downregulation of barrier protective IFN-β production. Our findings highlight the importance of IFN-β production by infected BMECs in preserving BBB function and preventing access of blood-borne infectious viruses to the brain. IMPORTANCE: Coronaviruses (CoVs) infect several mammals including humans and are associated with respiratory, gastrointestinal and/or neurological diseases. Some evidences suggest that human respiratory CoVs may show neuroinvasive properties. Indeed, the SARS-CoV, causing severe acute respiratory syndrome, and the CoVs OC43 and 229E were found in the brains of SARS and multiple sclerosis patients respectively. These finding suggest that hematogenous spread CoVs may gain access to CNS at the BBB level. Herein we report for the first time that CoVs exhibit ability to cross the BBB according to strain virulence. BBB invasion by CoVs correlates with viral-induced disruption of tight junctions on BMECs, leading to BBB dysfunction and enhanced permeability. We provide evidence that production of IFN-β by BMECs during CoV infection may prevent BBB breakdown and brain viral invasion
ISSN: 0022-538X

hal-01187308
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187308
DOI : 10.1128/JVI.01501-15
PUBMED : 26202229

Éditeur(s) : HAL CCSD
Résumé : International audience
Acute viral hepatitis results from an inefficient innate immune response to clear the virus and a delayed immune adaptive response. Murine hepatitis virus (MHV) infection represents a unique animal model to identify new escape mechanisms in liver of innate immune responses. The objective of this study was to identify early disorders in TLRs, helicases, cytokines and chemokines favoring the development of a fulminant hepatitis. Groups of C57BL/6 WT and TLR2-/- mice were infected with highly hepatotropic MHV3 and/or weakly hepatotropic MHV-A59 viruses. Histopathological analysis of liver and mRNA expression levels of viral nucleoprotein, viral sensors, interferons, cytokines and chemokines assessed by RT-qPCR were done in the first 3 days of infection. The results showed that liver damages, viral replication and mRNA levels of TLR-2, TLR-3, RIG-1, MDA-5, IL-33, IFN-b, CXCL1, CXCL9, CXCL-10, CXCL-11, CCL3, CCL5, IL-6 and TNF-a increased higher or appeared sooner in MHV3-infected WT than in MHV-A59 and TLR2-/- mice. To address the role of hepatocytes in TLR2-dependent viral replication and innate immune factors, in vitro viral infections were performed on FL83B cells. The results showed that viral replication and mRNA levels of TLR-2 and IL-6 occurred sooner than those of other innate immune parameters. Moreover, blockade of TLR-2 by siRNA decreased IFN-b, TNF-a, CXCL-1, CXCL-10 and CCL-2 expression in infected hepatocytes and also inhibited the viral replication of MHV-A59, and at a lesser extent of MHV3, suggesting that TLR-2 signaling promotes simultaneously the viral replication and the production of innate immune factors in hepatocytes, exacerbating viral hepatitis.
Frontiers of Immunology
Milan, Italy

hal-01118155
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118155
DOI : 10.3389/conf.fimmu.2013.02.00648

Éditeur(s) : HAL CCSD
Résumé : International audience
Viral replication in the liver is generally detected by cellular endosomal Toll-like receptors (TLRs) and cytosolic helicase sensors that trigger antiviral inflammatory responses. Recent evidence suggests that surface TLR2 may also contribute to viral detection through recognition of viral coat proteins but its role in the outcome of acute viral infection remains elusive. In this study, we examined in vivo the role of TLR2 in acute infections induced by the highly hepatotrophic mouse hepatitis virus (MHV) type 3 and weakly hepatotrophic MHV-A59 serotype. To address this, C57BL/6 (wild-type; WT) and TLR2 knockout (KO) groups of mice were intraperitoneally infected with MHV3 or MHV-A59. MHV3 infection provoked a fulminant hepatitis in WT mice, characterized by early mortality and high alanine and aspartate transaminase levels, histopathological lesions and viral replication whereas infection of TLR2 KO mice was markedly less severe. MHV-A59 provoked a comparable mild and subclinical hepatitis in WT and TLR2 KO mice. MHV3-induced fulminant hepatitis in WT mice correlated with higher hepatic expression of interferon-β, interleukin-6, tumour necrosis factor-α, CXCL1, CCL2, CXCL10 and alarmin (interleukin-33) than in MHV-A59-infected WT mice and in MHV3-infected TLR2 KO mice. Intrahepatic recruited neutrophils, natural killer cells, natural killer T cells or macrophages rapidly decreased in MHV3-infected WT mice whereas they were sustained in MHV-A59-infected WT mice and MHV3-infected TLR2 KO. MHV3 in vitro infection of macrophagic cells induced rapid and higher viral replication and/or interleukin-6 induction in comparison to MHV-A59, and depended on viral activation of TLR2 and p38 mitogen-activated protein kinase. Taken together, these results support a new aggravating inflammatory role for TLR2 in MHV3-induced acute fulminant hepatitis. © 2016 John Wiley & Sons Ltd
Immunology

Droits : info:eu-repo/semantics/OpenAccess
hal-01373946
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01373946
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01373946/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01373946/file/Toll-like%20receptor%20%28tlr%29-2%20exacerbates%20murine%20acute%20viral%20hepatitis.pdf
DOI : 10.1111/imm.12627