CATABOLISM OF LIPOPROTEIN-X INDUCED BY INFUSION OF 10-PERCENT FAT EMULSION

The clinical significance of lipoprotein-X (Lp-X) induced by intraveno us infusion of 10% fat emulsion was assessed, with special reference t o atherogenesis, by in vitro experiment using purified Lp-X from the s era of patients receiving Intralipid 10%. Lp-X appeared after long-ter m intravenous infusion of 10% fat emulsion in the patients with intest inal fistula due to the anastomotic leakage. To clarify the role of Lp -X in terms of atherogenicity, the cholesterol metabolism of Lp-X in m acrophages as scavenger cells and in hepatocytes as parenchymal cells was studied. When [H-3]cholesterol-labeled Lp-X or oxidized low-densit y lipoprotein (o-LDL) was incubated with J-774 macrophages, the incorp oration of Lp-X into macrophages was negligible compared with o-LDL. W hen Lp-X or high-density lipoprotein (HDL) was incubated with J-774 ma crophages laden with [H-3]cholesterol, the release of cholesterol from macrophages was enhanced by Lp-X as well as HDL. When [H-3] cholester ol-labeled Lp-X LDL or HDL was incubated with the human hepatoma cell line of Hep G(2) cells, the incorporation of Lp-X into Hep G(2) cells was less than that of LDL, but similar to that of HDL. From these find ings, it is suggested that the catabolism of Lp-X cholesterol generate d with intravenous 10% fat emulsion was mediated by hepatocytes rather than by macrophages, indicating that the hyperlipidemia due to increa sed Lp-X may not be atherogenic. (C) Elsevier Science Inc. 1997.