Effects of a perfluorochemical emulsion on the fate of circulating Pseudomonas aeruginosa

Abstract

Because mononuclear phagocytes take up perfluorochemical emulsions (PFCE), we examined how prior treatment with PFCE affects the fate of circulating bacteria. Rats were preinjected with three daily intravenous injections of PFCE (2.0 ml/100 g) containing 12.5% (vol/vol) of a 4:1 mixture of F-dimethyl adamantane and F-trimethylbicyclo-nonane, 2.5% (wt/vol) Pluronic F-68 as the emulsifying agent, and 3% (wt/vol) hydroxyethyl starch as the oncotic agent.Pseudomonas aeruginosa orStaphylococcus aureus were injected 4 h after the third PFCE injection. PFCE pretreatment decreased the rate and extent of vascular clearance of P. aeruginosa, with decreased uptake by the liver. Importantly, there were significant decreases in killing ofP. aeruginosa in the liver, lungs, spleen, and kidneys of PFCE animals. PFCE did not alter the clearance of S. aureus from the circulation. However, hepatic uptake was reduced, with concomitant increases in lung and kidney uptake. Ultrastructure of Kupffer cells revealed PFCE inclusions and extensive vacuolization. These experiments demonstrate that the clearance kinetics and organ distribution of circulatingP. aeruginosa and their subsequent killing are altered by PFCE. Diminished hepatic phagocyte function leads to a decrease in vascular clearance of circulating bacteria, increased uptake in other reticuloendothelial organs, and decreased bactericidal activity versus P. aeruginosa.