Effect of Intravenous Lipid Emulsions on Hepatic Cholesterol Metabolism

BACKGROUNDTotal parenteral nutrition offers the chance of survival to children who have had extensive gut resections or gut failure. However, in infants it is often associated with serious complications including cholestatic liver disease. The causes of these complications remain unclear, although it has been suggested that the lipid emulsions used in total parenteral nutrition may be responsible. METHODSAn in vitro system was developed to study the effect of lipid emulsions on hepatic cholesterol metabolism using cultured hepatocytes. RESULTSIncubations of Hep G2 cells with medium containing Intralipid (Pharmacia and Upjohn, Milton Keynes, UK) demonstrated that the fat emulsion mediated a powerful dose-dependent but reversible inhibition of cholesterol uptake. In addition Intralipid was shown to stimulate the efflux of cholesterol from Hep G2 cells. The component or components of the Intralipid responsible for these effects and the mechanism by which they act remain to be established. CONCLUSIONSIntravenous lipid emulsions may interfere with hepatic cholesterol metabolism in vivo. This may have implications for the development of total parenteral nutrition–associated cholestasis in neonates.