• Michel Carles, Brant M Wagener, Mathieu Lafargue, Jérémie Roux, Karen Iles, Dong Liu, Cilina Ann Rodriguez, Naseem Anjum, Jaroslaw Zmijewski, Jean-Ehrland Ricci, and Jean-Francois Pittet.
• From the Department of Anesthesiology, University of Nice-Sophia-Antipolis, Nice, France (M.C.); French Institute of Health and Medical Research U1065, University of Nice-Sophia-Antipolis, Nice, France (J.-E.R.); Department of Anesthesiology, University of California San Francisco, San Francisco, California (M.L., J.R.); and Departments of Anesthesiology (B.M.W., K.I., D.L., C.A.R., N.A., J.-F.P.), Environmental Health Sciences (K.I.), Surgery (J.-F.P.), Medicine (J.Z.) and Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama (J.-F.P.).
• Anesthesiology. 2014 Jun 1; 120 (6): 1450-62.

BackgroundThe heat-shock response (HSR) protects from insults, such as ischemia-reperfusion injury, by inhibiting signaling pathways activated by sterile inflammation. However, the mechanisms by which the HSR activation would modulate lung damage and host response to a bacterial lung infection remain unknown.MethodsHSR was activated with whole-body hyperthermia or by intraperitoneal geldanamycin in mice that had their lungs instilled with Pseudomonas aeruginosa 24 h later (at least six mice per experimental group). Four hours after instillation, lung endothelial and epithelial permeability, bacterial counts, protein levels in bronchoalveolar lavage fluid, and lung myeloperoxidase activity were measured. Mortality rate 24 h after P. aeruginosa instillation was recorded. The HSR effect on the release of interleukin-10 and killing of P. aeruginosa bacteria by a mouse alveolar macrophage cell line and on neutrophil phagocytosis was also examined.ResultsHSR activation worsened lung endothelial (42%) and epithelial permeability (50%) to protein, decreased lung bacterial clearance (71%), and increased mortality (50%) associated with P. aeruginosa pneumonia, an effect that was not observed in heat-shock protein-72-null mice. HSR-mediated decrease in neutrophil phagocytosis (69%) and bacterial killing (38%) by macrophages was interleukin-10 dependent, a mechanism confirmed by increased lung bacterial clearance and decreased mortality (70%) caused by P. aeruginosa pneumonia in heat-shocked interleukin-10-null mice.ConclusionsPrior HSR activation worsens lung injury associated with P. aeruginosa pneumonia in mice via heat-shock protein-72- and interleukin-10-dependent mechanisms. These results provide a novel mechanism for the immunosuppression observed after severe trauma that is known to activate HSR in humans.

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