title: Antioxidants improve antibacterial function in hyperoxia-exposed macrophages.
abstract: Hyperoxia and pulmonary infections are well known to increase the risk of acute and chronic lung injury in newborn infants, but it is not clear whether hyperoxia directly increases the risk of pneumonia. The purpose of this study was to examine: (1) the effects of hyperoxia and antioxidant enzymes on inflammation and bacterial clearance in mononuclear cells and (2) developmental differences between adult and neonatal mononuclear cells in response to hyperoxia. Mouse macrophages were exposed to either room air or 95% O2 for 24 h and then incubated with Pseudomonas aeruginosa. After 1 h, bacterial adherence, phagocytosis, and macrophage inflammatory protein (MIP)-1alpha production were analyzed. Bacterial adherence increased 5.8-fold (p < 0.0001), phagocytosis decreased 60% (p < 0.05), and MIP-1alpha production increased 49% (p < 0.05) in response to hyperoxia. Overexpression of MnSOD or catalase significantly decreased bacterial adherence by 30.5%, but only MnSOD significantly improved bacterial phagocytosis and attenuated MIP-1alpha production. When monocytes from newborns and adults were exposed to hyperoxia, phagocytosis was impaired in both groups. However, adult monocytes were significantly more impaired than neonatal monocytes. Data indicate that hyperoxia significantly increases bacterial adherence while impairing function of mononuclear cells, with adult cells being more impaired than neonatal cells. MnSOD reduces bacterial adherence and inflammation and improves bacterial phagocytosis in mononuclear cells in response to hyperoxia, which should minimize the development of oxidant-induced lung injury as well as reducing nosocomial infections.
authors: CardioPulmonary Research Institute, Winthrop University Hospital, State University of New York at Stony Brook School of Medicine, Mineola, NY 11501, USA.
authors: Yuko
authors: Y
authors: Arita
authors: Jeffrey A
authors: JA
authors: Kazzaz
authors: Ansamma
authors: A
authors: Joseph
authors: Hshi-chi
authors: HC
authors: Koo
authors: Yuchi
authors: Y
authors: Li
authors: Jonathan M
authors: JM
authors: Davis
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002448:Cell Adhesion; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018496:Hyperoxia / Q000276:immunology*; D019402:Macrophage Inflammatory Proteins / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D010088:Oxidoreductases / Q000378:metabolism*; D010587:Phagocytosis; D011550:Pseudomonas aeruginosa / Q000276:immunology*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D019402:Macrophage Inflammatory Proteins; D010088:Oxidoreductases; D013482:Superoxide Dismutase