Regulation of rat plasma and cerebral cortex oxylipin concentrations with increasing levels of dietary linoleic acid

• Published in: Prostaglandins, leukotrienes and essential fatty acids leukotrienes and essential fatty acids, 2018-11, Vol.138, p.71-80
• Main Authors: Taha, Ameer Y, Hennebelle, Marie, Yang, Jun, Zamora, Daisy, Rapoport, Stanley I, Hammock, Bruce D, Ramsden, Christopher E
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Endocrinology & Metabolism
• ISSN: 0952-3278; 1532-2823
• DOI: 10.1016/j.plefa.2016.05.004

Abstract Linoleic acid (LA, 18:2n-6) is the most abundant polyunsaturated fatty acid in the North American diet and is a precursor to circulating bioactive fatty acid metabolites implicated in brain disorders. This exploratory study tested the effects of increasing dietary LA on plasma and cerebral cortex metabolites derived from LA, it's elongation-desaturation products dihomo-gamma linolenic (DGLA, 20:3n-6) acid and arachidonic acid (AA, 20:4n-6), as well as omega-3 alpha-linolenic (α-LNA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). Plasma and cortex were obtained from rats fed a 0.4%, 5.2% or 10.5% energy LA diet for 15 weeks and subjected to liquid chromatography tandem mass spectrometry analysis. Total oxylipin concentrations, representing the esterified and unesterified pool, and unesterified oxylipins derived from LA and AA were significantly increased and EPA metabolites decreased in plasma at 5.2% or 10.5% energy LA compared to 0.4% energy LA. Unesterified plasma DHA metabolites also decreased at 10.5% energy LA. Total oxylipins did not significantly change in cortex, whereas unesterified LA and AA metabolites increased and unesterified EPA metabolites decreased at 5.2 or 10.5% LA. DGLA and α-LNA metabolites did not significantly change in plasma or cortex. Dietary LA lowering represents a feasible approach for targeting plasma and brain LA, AA, EPA or DHA-derived metabolite concentrations.