title: Perfluorohexane attenuates proinflammatory and procoagulatory response of activated monocytes and alveolar macrophages.
abstract: BACKGROUND
  A number of studies have demonstrated the effectiveness of liquid ventilation with perfluorocarbons in improving pulmonary function in acute respiratory distress syndrome. Although it is known that perfluorocarbon-associated gas exchange facilitates lung mechanics and oxygenation, the complete mechanism by which perfluorocarbons exert their beneficial effects in acute lung injury still remains unclear. Possibly, an influence of perfluorocarbons on proinflammatory and procoagulant features of monocytic cells present in the alveolar space, such as alveolar macrophages (AMs), may be involved. Therefore, we examined in an in vitro model the effects of perfluorocarbon on both activated mononuclear blood cells (MBCs) and AMs by monitoring the expression of interleukin (IL)-1 beta, tumor necrosis factor (TNF)alpha, and tissue factor (TF).
  
  
  METHODS
  Mononuclear blood cells, obtained from peripheral blood of healthy volunteers, or AMs from diagnostic bronchoalveolar lavage were stimulated by incubation with lipopolysaccharide in the presence of different amounts of perfluorohexane, which was devoid of cytotoxicity.
  
  
  RESULTS
  Using both video-enhanced contrast and electron microscopy, the authors observed that perfluorohexane droplets were phagocytosed by activated monocytes as well as by in vitro--cultured AMs within 1--3 h. After lipopolysaccharide stimulation of monocytes or AMs, we observed a down-regulation of TF mRNA and a significant inhibition (P < 0.05) of cellular TF antigen by perfluorohexane. In addition, the concentration of both IL-1 beta and TNF alpha in the supernatant of lipopolysaccharide-stimulated MBC was significantly decreased (P < 0.01) by perfluorohexane compared with controls without perfluorohexane. By preincubation of lipopolysaccharide-containing medium with perfluorohexane, the authors could exclude that the inhibitory effect of perfluorohexane was caused by binding or sequestering limited amounts of lipopolysaccharide.
  
  
  CONCLUSIONS
  Taken together, our results demonstrate an interference of perfluorohexane with the expression of the procoagulant protein TF on monocytes and AMs as well as with the release of proinflammatory cytokines by MBCs. These effects may contribute to the protective role of liquid ventilation with perfluorocarbons in injuries associated with local activation of inflammatory processes.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus, Dresden, Germany. tkoch@rcs.urz.tu-dresden.de
authors.forename: T
authors.initials: T
authors.lastname: Koch
authors.forename: M
authors.initials: M
authors.lastname: Ragaller
authors.forename: D
authors.initials: D
authors.lastname: Haufe
authors.forename: A
authors.initials: A
authors.lastname: Hofer
authors.forename: M
authors.initials: M
authors.lastname: Grosser
authors.forename: D M
authors.initials: DM
authors.lastname: Albrecht
authors.forename: M
authors.initials: M
authors.lastname: Kotzsch
authors.forename: T
authors.initials: T
authors.lastname: Luther
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D005466:Fluorocarbons / Q000494:pharmacology*; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism; D021061:Liquid Ventilation; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D010587:Phagocytosis; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D005466:Fluorocarbons; D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; C078626:perflexane