Journal of Lipid Research, Vol 29, 191-201, Copyright © 1988 by Lipid Research, Inc.
Hepatic perfusate very low density lipoproteins obtained from fat-fed nonhuman primates stimulate cholesterol esterification in macrophages
PA Soltys, H Gump, L Hennessy, T Mazzone, KD Carey, HC McGill Jr, GS Getz and SR Bates
Department of Pathology, University of Chicago, IL.
The livers of both baboons and rhesus monkeys fed a high fat, high
cholesterol diet secreted very low density lipoproteins (VLDL) that were
enriched in cholesteryl ester and apoe as compared to VLDL secreted by the
livers of chow-fed animals. Stimulation of macrophage cholesterol
esterification by the experimental VLDL was compared to that produced by
the standard beta-VLDL obtained from the plasma of a rhesus monkey fed 25%
coconut oil plus 2% cholesterol. This standard beta-VLDL stimulated 7- to
10-fold more esterification than did the bovine albumin control. Hepatic
VLDL from fat-fed animals stimulated esterification in J774 macrophages 50
to 150% as well as did the standard beta-VLDL, even though hepatic VLDL did
not display beta electrophoretic mobility on agarose gel electrophoresis.
Plasma VLDL from lard-fed baboons did not exhibit beta electrophoretic
mobility but did stimulate esterification in macrophages. Baboons were
divided into high and low responders based on the change in plasma
cholesterol levels in response to a high fat, high cholesterol diet. Both
plasma and hepatic VLDL from high responders stimulated cholesterol
esterification, whereas hepatic VLDL obtained from low responders or
chow-fed baboons did not stimulate cholesterol esterification in
macrophages. There was a strong positive correlation (r = 0.866) between
the number of apoE molecules per VLDL particle in VLDL obtained from
chow-fed, lard-fed, or coconut oil-fed primates and the rate of cholesterol
esterification in macrophages. Our results show that hepatic perfusate VLDL
obtained from fat- and cholesterol-fed primates have compositional and
functional properties usually ascribed to circulating beta-VLDL, without
displaying beta mobility, and indicate that the liver may be an important
source of atherogenic lipoproteins.