Effects of oleic acid and macrophage recruitment on cholesterol efflux in cell culture and in vivo.
OBJECTIVE
Monounsaturated fatty acids in diets are beneficial for the plasma lipoprotein profile, but studies in cell culture point out that they may also be detrimental by inhibiting cholesterol efflux to apo AI.


RESULTS
In the present study we used mouse peritoneal macrophages, loaded with cholesterol and upregulated by cyclic AMP or by LXR/RXR ligands and compared the effect of oleic acid on cholesterol efflux to 3 different acceptors. Inhibition of cholesterol efflux by oleic acid ranged from 10 to 25% with HDL or 2.5% mouse serum, while efflux to phosphatidyl choline vesicles was not affected. Previously we reported that the LXR ligand, TO901317, retarded cholesterol removal in vivo from a modified LDL depot in muscle. This could have resulted from inhibition by unsaturated fatty acids or from reduction in macrophage recruitment due to the anti-inflammatory action of LXR.


CONCLUSIONS
Our current findings, of retardation of cholesterol clearance from the depot in the presence of low macrophage recruitment, support the latter possibility.
Department of Experimental Medicine and Cancer Research, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
Olga
O
Stein
Yedida
Y
Dabach
Mazal
M
Ben-Naim
Gideon
G
Halperin
Yechezkiel
Y
Stein
D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors / Q000502:physiology; D000818:Animals; D050197:Atherosclerosis / Q000628:therapy; D002465:Cell Movement; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000502:physiology; D008074:Lipoproteins / Q000037:antagonists & inhibitors / Q000502:physiology; D000071518:Liver X Receptors; D008264:Macrophages / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008814:Mice, Inbred NZB; D019301:Oleic Acid / Q000494:pharmacology*; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D051122:Scavenger Receptors, Class B / Q000502:physiology
C487540:ABCG1 protein, mouse; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters; D004268:DNA-Binding Proteins; D008074:Lipoproteins; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D019301:Oleic Acid; D002784:Cholesterol