Abstract 94

Aims of this study: To examine if PFC changed the potential of blood cells to modulate broncho- and vasoconstriction by producing vasoactive substances like ET-1 or NO. The lowest PFC concentration used, 0.001% (w/v), was relevant to serum concentrations of PFC obtained in liquid-ventilated individuals, whereas the highest concentration, 50% (w/v), would mimic a situation where leukocytes are presented to PFC-filled airways

Methods: Leukocytes from 6 healthy individuals were incubated in their natural habitate (whole blood) in the presence of two different PFC (perfluorodecalin and perflubron). The responses in ET-1 or NO (indirectly measured as nitrite/nitrate) production were examined at increasing PFC concentrations after 6h of PFC/whole blood contact using ELISA for estimation of plasma ET-1 and a fluorometric assay to measure NO2-/NO3-.

Results: Synthesis of ET-1 or NO could not be induced beyond background levels in the presence of PFC. Basal plasma levels of ET-1 and NO2-/NO3- were 0.59 ± 0.07 pg/ml (mean ± SEM) and 50 ± 9 µM, respectively. Perflubron and perfluorodecalin did not increase or decrease levels of ET-1 or NO2-/NO3- compared to non-PFC-supplemented cultures.

Conclusion: PFC liquids do not stimulate leukocytes to produce substances that may modulate constriction or dilatation in the vascular and respiratory tract systems. The present results adds to the proven biological inertness of these chemicals.