Catabolism of lipoprotein-X induced by infusion of 10% fat emulsion.
The clinical significance of lipoprotein-X (Lp-X) induced by intravenous infusion of 10% fat emulsion was assessed, with special reference to atherogenesis, by in vitro experiment using purified Lp-X from the sera of patients receiving Intralipid 10%. Lp-X appeared after long-term intravenous infusion of 10% fat emulsion in the patients with intestinal fistula due to the anastomotic leakage. To clarify the role of Lp-X in terms of atherogenicity, the cholesterol metabolism of Lp-X in macrophages as scavenger cells and in hepatocytes as parenchymal cells was studied. When [3H]cholesterol-labeled Lp-X or oxidized low-density lipoprotein (o-LDL) was incubated with J-774 macrophages, the incorporation of Lp-X into macrophages was negligible compared with o-LDL. When Lp-X or high-density lipoprotein (HDL) was incubated with J-774 macrophages laden with [3H]cholesterol, the release of cholesterol from macrophages was enhanced by Lp-X as well as HDL. When [3H]cholesterol-labeled Lp-X LDL or HDL was incubated with the human hepatoma cell line of Hep G2 cells, the incorporation of Lp-X into Hep G2 cells was less than that of LDL, but similar to that of HDL. From these findings, it is suggested that the catabolism of Lp-X cholesterol generated with intravenous 10% fat emulsion was mediated by hepatocytes rather than by macrophages, indicating that the hyperlipidemia due to increased Lp-X may not be atherogenic.
Abe
M
M
Department of Surgery, Awa Medical Center, Chiba, Japan.
Kawano
M
M
Tashiro
T
T
Yamamori
H
H
Takagi
K
K
Morishima
Y
Y
Shirai
K
K
Saitou
Y
Y
Nakajima
N
N
D000818:Animals; D001161:Arteriosclerosis / Q000209:etiology; D001693:Biological Transport, Active; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D006949:Hyperlipidemias / Q000209:etiology; D008073:Lipoprotein-X / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D010289:Parenteral Nutrition, Total / Q000009:adverse effects; D014316:Tritium
D005217:Fat Emulsions, Intravenous; D008073:Lipoprotein-X; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D014316:Tritium; D002784:Cholesterol