Journal of Lipid Research, Vol 25, 283-287, Copyright © 1984 by Lipid Research, Inc.
The interaction of human apoB-containing lipoproteins with mouse peritoneal macrophages: a comparison of Lp(a) with LDL
F Krempler, GM Kostner, A Roscher, K Bolzano and F Sandhofer
Cholesteryl ester accumulation in macrophages and foam cell formation is
believed to play an important role in atherogenesis. The effect of Lp(a) on
the incorporation of [14C]oleate into cholesteryl esters was studied in
mouse peritoneal macrophages. In view of the physico- chemical similarities
between Lp(a) and LDL, the results were compared with those obtained with
LDL. Native Lp(a) and LDL did not stimulate cholesteryl ester formation.
Incubation of macrophages with Lp(a)- or LDL-dextran sulfate complexes
caused a significant increase in cholesteryl ester formation. A similar
effect was observed when Lp(a) or LDL were incubated with macrophages in
the presence of antibodies directed against the specific Lp(a) apoprotein
or against LpB. Treatment of Lp(a) with acetic anhydride or malondialdehyde
(MDA) was followed by precipitation of most of the lipoprotein. Therefore,
these modifications were not suitable to study the uptake of modified Lp(a)
by macrophages. Studies with acetyl-LDL or MDA-treated LDL caused the
well-known stimulation of [14C]oleate incorporation into cholesteryl
esters. Thus, the modification of Lp(a) by sulfated polysaccharides or by
treatment with antibodies yields similar cholesteryl ester deposition in
mouse peritoneal macrophages as observed with modified LDL. This might be
one mechanism by which Lp(a) exerts its atherogenicity.