title: Training modifies innate immune responses in blood monocytes and in pulmonary alveolar macrophages.
abstract: In humans, strenuous exercise causes increased susceptibility to respiratory infections associated with down-regulated expression of Toll-like receptors (TLRs) and costimulatory and antigen-presenting molecules. Lower airway diseases are also a common problem in sport and racing horses. Because innate immunity plays an essential role in lung defense mechanisms, we assessed the effect of acute exercise and training on innate immune responses in two different compartments. Blood monocytes and pulmonary alveolar macrophages (PAMs) were collected from horses in untrained, moderately trained, intensively trained, and deconditioned states before and after a strenuous exercise test. The cells were analyzed for TLR messenger ribonucleic acid (mRNA) expression by real-time PCR in vitro, and cytokine production after in vitro stimulation with TLR ligands was measured by ELISA. Our results showed that training, but not acute exercise, modified the innate immune responses in both compartments. The mRNA expression of TLR3 was down-regulated by training in both cell types, whereas the expression of TLR4 was up-regulated in monocytes. Monocytes treated with LPS and a synthetic diacylated lipoprotein showed increased cytokine secretion in trained and deconditioned subjects, indicating the activation of cells at the systemic level. The production of TNF-α and IFN-β in nonstimulated and stimulated PAMs was decreased in trained and deconditioned horses and might therefore explain the increased susceptibility to respiratory infections. Our study reports a dissociation between the systemic and the lung response to training that is probably implicated in the systemic inflammation and in the pulmonary susceptibility to infection.
authors: 1 Center of Equine Sports Medicine, University of Liege, Liege, Belgium.
authors: Linda
authors: L
authors: Frellstedt
authors: Ingrid
authors: I
authors: Waldschmidt
authors: Philippe
authors: P
authors: Gosset
authors: Christophe
authors: C
authors: Desmet
authors: Dimitri
authors: D
authors: Pirottin
authors: Fabrice
authors: F
authors: Bureau
authors: Frédéric
authors: F
authors: Farnir
authors: Thierry
authors: T
authors: Franck
authors: Marie-Capucine
authors: MC
authors: Dupuis-Tricaud
authors: Pierre
authors: P
authors: Lekeux
authors: Tatiana
authors: T
authors: Art
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005260:Female; D006736:Horses; D006854:Hydrocortisone / Q000378:metabolism; D007113:Immunity, Innate / Q000276:immunology*; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism; D008137:Longitudinal Studies; D008168:Lung / Q000276:immunology* / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000276:immunology* / Q000378:metabolism; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism; D010805:Physical Conditioning, Animal; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051193:Toll-Like Receptors / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; D016899:Interferon-beta; D006854:Hydrocortisone
keywords: equine; exercise; innate immunity; monocytes; pulmonary alveolar macrophages