title: Chronic but not acute treatment with conjugated linoleic acid (CLA) isomers (trans-10, cis-12 CLA and cis-9, trans-11 CLA) affects lipid metabolism in Caco-2 cells.
abstract: Conjugated linoleic acid (CLA) has profound effects on hepatic and adipocyte lipid metabolism, but little is known about its effects on intestinal lipid metabolism. We investigated the acute (22 h) and acute-after-chronic (22 h after 19 d) effects of trans-10, cis-12 CLA (t10,c12-CLA) and cis-9, trans-11 CLA (c9, t11-CLA) on triacylglycerol (TAG)-rich lipoprotein (TRL) metabolism, de novo TAG, phospholipid (PL) ((14)C-glycerol) and apolipoprotein B (apoB) ((35)S-methionine) synthesis and secretion, in the colon carcinoma (Caco-2) cell model of intestinal lipoprotein metabolism. Acute treatment with either CLA isomer did not affect TRL metabolism. However, chronic t10,c12-CLA and c9,t11-CLA supplementation followed by acute palmitic acid (PA) treatment increased the ratio of cellular to secreted de novo TAG (cTAG/sTAG) (P < or = 0.03) as a result of increased cellular de novo TAG levels. Chronic Caco-2 cell t10,c12-CLA supplementation, prior to the acute oleic acid (OA) treatment, significantly increased (P = 0.005) the ratio of cellular de novo TAG to de novo PL (cTAG/cPL), to a greater extent than that following chronic linoleic acid (LA) (P = 0.001) or c9,t11-CLA supplementation (P = 0.005). Again, this effect was attributed to increased cellular de novo TAG synthesis. Neither CLA isomer affected the ratio of secreted de novo TAG to de novo PL (sTAG/sPL). No effects on Caco-2 cell apoB synthesis and secretion were observed after acute or chronic CLA treatments. In conclusion, chronic t10,c12-CLA supplementation modulated intestinal TRL metabolism, by increasing cellular de novo TAG synthesis but had no effect on de novo TAG secretion in Caco-2 cells.
authors.affiliation: Smurfit Institute of Genetics, Trinity College Dublin, Ireland.
authors.forename: Irene L
authors.initials: IL
authors.lastname: Black
authors.forename: Helen M
authors.initials: HM
authors.lastname: Roche
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gibney
mesh_terms: D018938:Caco-2 Cells; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D007536:Isomerism; D007700:Kinetics; D008041:Linoleic Acids / Q000494:pharmacology*; D050356:Lipid Metabolism; D013997:Time Factors
chemical_list: D005230:Fatty Acids, Nonesterified; D008041:Linoleic Acids