title: Dietary fish oil reduces intercellular adhesion molecule 1 and scavenger receptor expression on murine macrophages.
abstract: During atherogenesis, a pathological accumulation of lipids occurs within aortic intimal macrophages through uptake of oxidised low-density lipoprotein (LDL) via scavenger receptors. Here we investigate whether some of the anti-atherosclerotic effects ascribed to dietary fish oil are mediated through effects on macrophage intercellular adhesion molecule 1 (ICAM-1) and scavenger receptor expression. Mice were fed on a low fat diet (containing 25 g/kg corn oil) or on high fat diets containing 200 g/kg coconut oil, safflower oil or fish oil. Thioglycollate-elicited peritoneal macrophages were analysed for fatty acid composition by gas chromatography. Macrophage scavenger receptor A (MSR-A) type I+type II and ICAM-1 expression were measured by flow cytometry and the levels of mRNA coding for MSR-A type I, MSR-A type II and ICAM-1 were measured by reverse-transcription polymerase chain reaction. Feeding mice diets enriched with different fats resulted in significant changes in the fatty acid profile of macrophages, which reflected the fatty acid compositions of the diets. Macrophages from the fish oil fed mice had the lowest expression of ICAM-1 and MSR-A at the level of both mRNA and cell surface expression. The reduced expression of ICAM-1 and MSR-A on macrophages from mice fed on a fish oil-rich diet supports our hypothesis that part of the protective effect of fish oil against atherosclerosis might be due to an altered macrophage phenotype and function ameliorating macrophage-induced plaque formation.
authors.affiliation: Institute of Human Nutrition, University of Southampton, Bassett Crescent East, SO16 7PX, Southampton, UK. eam@soton.ac.uk
authors.forename: E A
authors.initials: EA
authors.lastname: Miles
authors.forename: F A
authors.initials: FA
authors.lastname: Wallace
authors.forename: P C
authors.initials: PC
authors.lastname: Calder
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002849:Chromatography, Gas; D000074263:Coconut Oil; D003314:Corn Oil / Q000494:pharmacology; D018752:Diet, Fat-Restricted; D005395:Fish Oils / Q000494:pharmacology*; D005434:Flow Cytometry; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis* / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D008969:Molecular Sequence Data; D010938:Plant Oils / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011336:Probability; D012333:RNA, Messenger / Q000032:analysis; D011971:Receptors, Immunologic / Q000032:analysis* / Q000187:drug effects; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D012016:Reference Values; D012450:Safflower Oil / Q000494:pharmacology; D051122:Scavenger Receptors, Class B
chemical_list: D005395:Fish Oils; D008565:Membrane Proteins; D010938:Plant Oils; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D018799:Intercellular Adhesion Molecule-1; D012450:Safflower Oil; D003314:Corn Oil; D000074263:Coconut Oil