title: Antioxidants preserve macrophage phagocytosis of Pseudomonas aeruginosa during hyperoxia.
abstract: Pseudomonas. aeruginosa (PA) is a leading cause of nosocomial pneumonia in patients receiving mechanical ventilation with hyperoxia. Exposure to supraphysiological concentrations of reactive oxygen species during hyperoxia may result in macrophage damage that reduces their ability to phagocytose PA. We tested this hypothesis in cultured macrophage-like RAW 264.7 cells and alveolar macrophages from mice exposed to hyperoxia. Exposure to hyperoxia induced a similarly impaired phagocytosis of both the mucoid and the nonmucoid forms of PA in alveolar macrophages and RAW cells. Compromised PA phagocytosis was associated with cytoskeleton disorganization and actin oxidation in hyperoxic macrophages. To test whether moderate concentrations of O(2) limit the loss of phagocytic function induced by > or =95% O(2), mice and RAW cells were exposed to 65% O(2). Interestingly, although the resulting lung injury/cell proliferation was not significant, exposure to 65% O(2) resulted in a marked reduction in PA phagocytosis that was comparable to that of > or =95% O(2). Treatment with antioxidants, even post hyperoxic exposure, preserved actin cytoskeleton organization and phagocytosis of PA. These data suggest that hyperoxia reduces macrophage phagocytosis through effects on actin functions which can be preserved by antioxidant treatment. In addition, administration of moderate rather than higher concentrations of O2 does not improve macrophage phagocytosis of PA.
authors: Department of Pharmaceutical Sciences, St. John's University College of Pharmacy, Queens, NY 11439, USA.
authors: Dympna M P
authors: DM
authors: Morrow
authors: Tahereh
authors: T
authors: Entezari-Zaher
authors: John
authors: J
authors: Romashko
authors: Ali O
authors: AO
authors: Azghani
authors: Mohammad
authors: M
authors: Javdan
authors: Luis
authors: L
authors: Ulloa
authors: Edmund J
authors: EJ
authors: Miller
authors: Lin L
authors: LL
authors: Mantell
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002460:Cell Line; D018496:Hyperoxia / Q000503:physiopathology*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D010587:Phagocytosis / Q000187:drug effects*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000502:physiology*; D013482:Superoxide Dismutase / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D013482:Superoxide Dismutase