Perfluorochemical liquids do not stimulate endothelin-1 or nitric oxide production in human blood leukocytes

The purpose of these studies was to examine if perfluorochemical (PFC) liquids stimulate blood leukocytes to secrete nitric oxide (NO) and/or endothelin-1 (ET-1). As such, NO and ET-1 may modulate broncho- and vascular dilatation and constriction, respectively, and thereby influence the clinical condition of a patient in respiratory distress with persistent pulmonary hypertension. Blood leukocytes in their natural habitat (whole blood) were incubated in the presence of two different perfluorochemicals (perflubron and perfluorodecalin). The overall response in ET-1 or NO (indirectly measured as nitrite/nitrate) production was examined at increasing PFC percentages (wt/vol) of PFC/whole blood. The lowest proportion used, 0.001% (wt/vol), was relevant to serum concentrations of PFC observed in liquid-ventilated individuals, whereas the highest proportion PFC, 50% (wt/vol), would mimic a situation where leukocytes are presented to PFC-filled airways. Plasma levels of freshly drawn blood, similar to levels of incubated (6 h) non-PFC-supplemented cultures, were ET-1 0.59 +/- 0.07 pg/ml (6 h, mean +/- SEM) and NO(-2)/NO(-3) 50 +/- 9 microM (6 h). Perflubron or perfluorodecalin did not induce significant differences in ET-1 or NO(-2)/NO(-3) levels as function of PFC type or dose. In conclusion, PFC liquids do not stimulate production in leukocytes in vitro of substances that may modulate constriction or dilatation in the vascular and respiratory tract systems.