PERFLUOROCARBON PROTECTS LUNG EPITHELIAL-CELLS FROM NEUTROPHIL-MEDIATED INJURY IN AN IN-VITRO MODEL OF LIQUID VENTILATION THERAPY

Liquid ventilation with perfluorocarbon has been effective in improvin g gas exchange and pulmonary function in the setting of acute respirat ory failure, How improvement is brought about remains unknown, In the present study, we examined perfluorocarbon for effects on neutrophil f unction and for effects on neutrophil-epithelial cell interactions tha t could underlie its in vivo activity. Exposure of neutrophils in vitr o to perfluorocarbon followed by washing did not interfere with their ability to generate oxidants or release proteolytic enzymes upon subse quent stimulation, Likewise, such treatment did not interfere with sub sequent adhesion of the neutrophils to monolayers of epithelial cells or with neutrophil-induced injury to these cells. In contrast, when pe rfluorocarbon was added to neutrophils and epithelial cells together a nd the neutrophils then stimulated, it reduced their adhesive interact ion with the target cells and concomitantly reduced target cell injury , In companion studies, cells were obtained by bronchial lavage of per fluorocarbon-treated patients with acute respiratory distress syndrome (ARDS) and analyzed for oxidant production. Oxidant-generating capaci ty by the cells obtained from the bronchial lavage fluid was similar t o that of peripheral blood neutrophils. These data are consistent with the suggestion that perfluorocarbon protects cells in vitro from neut rophil-mediated injury, at least in part, by acting as a mechanical ba rrier, These findings are consistent with a potential mechanism of act ion in vivo.