title: Dietary (n-9) eicosatrienoic acid from a cultured fungus inhibits leukotriene B4 synthesis in rats and the effect is modified by dietary linoleic acid.
abstract: Eicosatrienoic acid (ETrA) is the (n-9) homologue of (n-6) arachidonic acid (AA) and (n-3) eicosapentaenoic acid (EPA). ETrA can be synthesized endogeneously, but tissue levels are normally undetectable except in essential fatty acid (EFA) deficiency. An ETrA-rich oil extracted from a cultured fungus was used to prepare diets which had varying levels of ETrA (0-8 g/kg diet) in combination with one of two levels of linoleic acid (LA, 2.2 or 9.5 g/kg diet). All diets were sufficient in essential fatty acids. Groups of rats were fed these diets for 4 wk after which leucocyte fatty acid content and leukotriene B4 (LTB4) synthesis were measured. The influence of dietary LA on ETrA accumulation in cells was studied and correlations with LTB4 synthesis determined. ETrA was efficiently incorporated into peritoneal exudate cell (PEC) phospholipids with no evident saturation being observed with levels up to 10 mol/100 mol total fatty acids in peritoneal exudate cells. Cellular ETrA levels were lower (P < 0.001) in rats fed the higher level of LA. ETrA accumulation in peritoneal exudate cells correlated (r(2) = 0.63, P < 0.05) with reduced LTB4 synthesis which was attributable to LTA hydrolase inhibition. Thus, dietary ETrA from a biological source can accumulate in leucocytes and suppress inflammatory eicosanoid synthesis. The findings justify further studies into the biochemical and anti-inflammatory effects of dietary ETrA, which could be incorporated into palatable food additives.
authors.affiliation: Rheumatology Unit, Royal Adelaide Hospital, Adelaide, SA, Australia.
authors.forename: L G
authors.initials: LG
authors.lastname: Cleland
authors.forename: R A
authors.initials: RA
authors.lastname: Gibson
authors.forename: M A
authors.initials: MA
authors.lastname: Neumann
authors.forename: T
authors.initials: T
authors.lastname: Hamazaki
authors.forename: K
authors.initials: K
authors.lastname: Akimoto
authors.forename: M J
authors.initials: MJ
authors.lastname: James
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D001202:Ascitic Fluid / Q000166:cytology; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D005260:Female; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D007975:Leukotriene B4 / Q000096:biosynthesis*; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000494:pharmacology*; D009090:Mucorales / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats
chemical_list: D004042:Dietary Fats, Unsaturated; D006893:Hydroxyeicosatetraenoic Acids; D008041:Linoleic Acids; D010743:Phospholipids; D007975:Leukotriene B4; C022022:5-hydroxy-6,8,11,14-eicosatetraenoic acid; D019787:Linoleic Acid; D001094:Arachidonate 5-Lipoxygenase; D015126:8,11,14-Eicosatrienoic Acid; C010944:mead acid