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Murru E, Carta G, Manca C, Sogos V, Pistis M, Melis M, Banni S. Conjugated Linoleic Acid and Brain Metabolism: A Possible Anti-Neuroinflammatory Role Mediated by PPARα Activation. Front Pharmacol 2021; 11:587140. [PMID: 33505308 PMCID: PMC7832089 DOI: 10.3389/fphar.2020.587140] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/17/2020] [Indexed: 12/24/2022] Open
Abstract
Fatty acids play a crucial role in the brain as specific receptor ligands and as precursors of bioactive metabolites. Conjugated linoleic acid (CLA), a group of positional and geometric isomers of linoleic acid (LA, 18:2 n-6) present in meat and dairy products of ruminants and synthesized endogenously in non-ruminants and humans, has been shown to possess different nutritional properties associated with health benefits. Its ability to bind to peroxisome proliferator-activated receptor (PPAR) α, a nuclear receptor key regulator of fatty acid metabolism and inflammatory responses, partly mediates these beneficial effects. CLA is incorporated and metabolized into brain tissue where induces the biosynthesis of endogenous PPARα ligands palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), likely through a positive feedback mechanism where PPARα activation sustains its own cellular effects through ligand biosynthesis. In addition to PPARα, PEA and OEA may as well bind to other receptors such as TRPV1, further extending CLA own anti-neuroinflammatory actions. Future studies are needed to investigate whether dietary CLA may exert anti-inflammatory activity, particularly in the setting of neurodegenerative diseases and neuropsychiatric disorders with a neuroinflammatory basis.
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Affiliation(s)
- Elisabetta Murru
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Gianfranca Carta
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Claudia Manca
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Valeria Sogos
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Marco Pistis
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy.,Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Sebastiano Banni
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
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In vitro study of the bioavailability of fatty acids in cow milk containing conjugated linoleic acids produced in vivo or added in synthetic form. Int Dairy J 2014. [DOI: 10.1016/j.idairyj.2014.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ritzenthaler KL, Shahin AM, Shultz TD, Dasgupta N, McGuire MA, McGuire MK. Dietary intake of c9,t11-conjugated linoleic acid correlates with its concentration in plasma lipid fractions of men but not women. J Nutr 2012; 142:1645-51. [PMID: 22833652 DOI: 10.3945/jn.111.156794] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The c9,t11-18:2 isomer of conjugated linoleic acid (c9,t11-CLA) represents the main dietary CLA form with putative health benefits. Whereas CLA intake influences the tissue CLA concentration, little is known about the association between dietary CLA and the CLA content of plasma lipid fractions. This study was designed to document fasting and nonfasting plasma c9,t11-CLA concentrations in a population of free-living adults (n = 94) and relate these concentrations to c9,t11-CLA intake. We also determined the c9,t11-CLA content of the primary plasma lipid fractions in a subset (n = 50) of our participants, related these to c9,t11-CLA intake, and determined whether c9,t11-CLA intake or plasma c9,t11-CLA was correlated with plasma cholesterol. Mean fasting plasma c9,t11-CLA concentrations were 0.46 ± 0.01 and 0.54 ± 0.01% (wt:wt) of total fatty acids for men and women, respectively (P < 0.05); nonfasting concentrations were 0.28 ± 0.01 and 0.38 ± 0.01% of total fatty acids, respectively (P < 0.001). All major esterified plasma lipid fractions contained c9,t11-CLA; TG had the highest percentages. In men, c9,t11-CLA intake correlated (r = 0.47; P < 0.05) with TG c9,t11-CLA content, suggesting that TG c9,t11-CLA may serve as a biomarker for c9,t11-CLA intake. In females, there were no correlations between c9,t11-CLA intake and the c9,t11-CLA content of any esterified plasma lipid fraction. In neither sex was there a relation between dietary c9,t11-CLA or plasma c9,t11-CLA concentration and circulating lipoprotein cholesterol concentration. The influence of sex on circulating c9,t11-CLA content and further validation of biomarkers of c9,t11-CLA intake warrant further investigation.
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Belda BJ, Lee Y, Vanden Heuvel JP. Conjugated linoleic acids and inflammation: isomer- and tissue-specific responses. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/clp.10.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Conjugated linoleic acid isomers, t10c12 and c9t11, are differentially incorporated into adipose tissue and skeletal muscle in humans. Lipids 2009; 44:983-8. [PMID: 19851798 DOI: 10.1007/s11745-009-3359-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 10/02/2009] [Indexed: 10/20/2022]
Abstract
Conjugated linoleic acid (CLA) is a popular supplement believed to enhance immune function, body composition and insulin sensitivity, but results of scientific studies investigating its effects are conflicting. The isomer- and tissue-specific effects of CLA may explain these conflicting results. Therefore, this study quantified the incorporation of the c9t11 and t10c12 CLA isomers into adipose tissue and skeletal muscle in response to supplementation in healthy, regularly-exercising, non-obese persons. The CLA group (n = 14) ingested 3.9 g per day CLA (50:50 t9c11:c10t12) and the placebo group (n = 11) 3.9 g per day high-oleic-acid sunflower oil for 12 weeks. Following supplementation, the t10c12 isomer was incorporated into adipose tissue triacylglycerol (P < 0.001), and the c9t11 isomer tended to increase in skeletal muscle phospholipids (P = 0.056). Therefore, human adipose tissue and skeletal muscle are enriched with CLA in an isomer-specific manner.
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Plourde M, Jew S, Cunnane SC, Jones PJH. Conjugated linoleic acids: why the discrepancy between animal and human studies? Nutr Rev 2008; 66:415-21. [DOI: 10.1111/j.1753-4887.2008.00051.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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GONG YUANSHENG, WEBER PETERF, RICHARDS MARKP. CHARACTERIZING QUALITY OF RENDERED DUCK FAT COMPARED TO OTHER FATS AND OILS. J FOOD QUALITY 2007. [DOI: 10.1111/j.1745-4557.2007.00113.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Turpeinen AM, Bärlund S, Freese R, Lawrence P, Brenna JT. Effects of conjugated linoleic acid on linoleic and linolenic acid metabolism in man. Br J Nutr 2007; 95:727-33. [PMID: 16571152 DOI: 10.1079/bjn20051432] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Evidence from animal studies suggests that conjugated linoleic acid (CLA) modulates plasma and tissue appearance of newly synthesized PUFA. The effects of a 1·2g (0·5% energy) daily intake of thecis-9,trans-11 (c9,t11) isomer of CLA,trans-10,cis-12 (t10,c12) isomer of CLA or olive oil (placebo) on linoleic acid (LA) and linolenic acid (LNA) metabolism in healthy human volunteers was investigated. Fifteen subjects were fed an experimental diet and supplemented withc9,t11-CLA,t10,c12-CLA or placebo for 7d before consuming a tracer dose of U-[13C]La (50%Mg) And U-[13C]Lna (50Mg). Blood Samples Were Taken At 0, 2, 4, 6, 8, 24, 48, 72 and 168%h and analysed using high-precision MS. No differences between the groups in peak plasma [13C]LA (10·3–11·6% of dose), [13C]LNA (2·5–2·9% of dose), [13C]arachidonic acid (0·09–0·12% of dose), [13C]EPA (0·04–0·06% of dose) or [13C]Dha (0c·06–0·10% of dose) were detected. ConcentrationV. time curves (area under the curve) also showed no significant differences between groups. This suggests that, in healthy human subjects consuming a diet with adequate intake of essential fatty acids, CLA does not affect metabolism of LA or LNA
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Affiliation(s)
- Anu M Turpeinen
- Department of Applied Chemistry and Microbiology (Nutrition), University of Helsinki, PO Box 66, 00014 University of Helsinki, Finland.
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Ritzenthaler KL, McGuire MK, McGuire MA, Shultz TD, Koepp AE, Luedecke LO, Hanson TW, Dasgupta N, Chew BP. Consumption of conjugated linoleic acid (CLA) from CLA-enriched cheese does not alter milk fat or immunity in lactating women. J Nutr 2005; 135:422-30. [PMID: 15735073 DOI: 10.1093/jn/135.3.422] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Isomers of conjugated linoleic acid (CLA) decreased milk fat, altered immunity, and reduced the risk for cardiovascular disease (CVD) in some animals. The major form of CLA in the human diet is c9,t11-18:2 (rumenic acid; RA). We studied the effects of high RA consumption on plasma and milk RA concentration, milk composition, immunity, and CVD risk factors in lactating women (n = 36) assigned to 1 of 3 treatments: control, low CLA cheese (LCLA; 160 mg RA/d), or high CLA cheese (HCLA; 346 mg RA/d). The increase in plasma RA concentration between baseline and 8 wk in women consuming HCLA cheese was significantly greater than that of controls. At study completion (8 wk), milk RA concentration among women consuming HCLA cheese was greater (P < 0.05) than that of controls (0.37 vs. 0.26% of fatty acids). Treatment did not affect milk fat, protein, or lactose concentrations, immune indices (e.g., plasma T-helper cells and interleukin-2), or measured risk factors for CVD (e.g., plasma triacylglyceride and cholesterol). In summary, consumption of a RA-enriched cheese modestly increased plasma and milk RA concentrations without affecting total milk fat, plasma and milk indices of immunity, or selected risk factors for CVD.
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Affiliation(s)
- Kristin L Ritzenthaler
- Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376, USA
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Fernie CE, Dupont IE, Scruel O, Carpentier YA, Sébédio JL, Scrimgeour CM. Relative absorption of conjugated linoleic acid as triacylglycerol, free fatty acid and ethyl ester in a functional food matrix. EUR J LIPID SCI TECH 2004. [DOI: 10.1002/ejlt.200300924] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Emken EA, Adlof RO, Duval SM, Shane JM, Walker PM, Becker C. Effect of triacylglycerol structure on absorption and metabolism of isotope-labeled palmitic and linoleic acids by humans. Lipids 2004; 39:1-9. [PMID: 15055228 DOI: 10.1007/s11745-004-1194-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of dietary TAG structure and fatty acid acyl TAG position on palmitic and linoleic acid metabolism was investigated in four middle-aged male subjects. The study design consisted of feeding diets containing 61 g/d of native lard (NL) or randomized lard (RL) for 28 d. Subjects then received an oral dose of either 1,3-tetradeuteriopalmitoyl-2-dideuteriolinoleoyl-rac-glycerol or a mixture of 1,3-dideuteriolinoleoyl-2-tetradeuteriopalmitoyl-rac-glycerol and 1,3-hexadeuteriopalmitoyl-2-tetradeuteriolinoleoyl-rac-glycerol. Methyl esters of plasma lipids isolated from blood samples drawn over a 2-d period were analyzed by GC-MS. Results showed that absorption of the 2H-fatty acids (2H-FA) was not influenced by TAG position. The 2H-FA at the 2-acyl TAG position were 85+/-4.6% retained after absorption. Substantial migration of 2H-16:0 (31.2+/-8.6%) from the sn-2 TAG position to the sn-1,3 position and 2H-18:2n-6 (52.8+/-6.4%) from the sn-1,3 position to the sn-2 position of chylomicron TAG occurred after initial absorption and indicates the presence of a previously unrecognized isomerization mechanism. Incorporation and turnover of the 2H-FA in chylomicron TAG, plasma TAG, and plasma cholesterol esters were not influenced by TAG acyl position. Accretion of 2H-16:0 from the sn-2 TAG position in 1-acylphosphatidylcholine was 1.7 times higher than 2H-16:0 from the sn-1,3 TAG positions. Acyl TAG position did not influence 2H-18:2n-6 incorporation in PC. The concentration of 2H-18:2n-6-derived 2H-20:4n-6 in plasma PC from subjects fed the RL diet was 1.5 times higher than for subjects fed the NL diet, and this result suggests that diets containing 16:0 located at the sn-2 TAG position may inhibit 20:4n-6 synthesis. The overall conclusion is that selective rearrangement of chylomicron TAG structures diminishes but does not totally eliminate the metabolic and physiological effects of dietary TAG structure.
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Affiliation(s)
- E A Emken
- USDA, ARS, NCAUR, Peoria, Illinois 61604, USA.
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Burdge GC, Finnegan YE, Minihane AM, Williams CM, Wootton SA. Effect of altered dietary n-3 fatty acid intake upon plasma lipid fatty acid composition, conversion of [13C]alpha-linolenic acid to longer-chain fatty acids and partitioning towards beta-oxidation in older men. Br J Nutr 2003; 90:311-21. [PMID: 12908891 DOI: 10.1079/bjn2003901] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of increased dietary intakes of alpha-linolenic acid (ALNA) or eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for 2 months upon plasma lipid composition and capacity for conversion of ALNA to longer-chain metabolites was investigated in healthy men (52 (SD 12) years). After a 4-week baseline period when the subjects substituted a control spread, a test meal containing [U-(13)C]ALNA (700 mg) was consumed to measure conversion to EPA, docosapentaenoic acid (DPA) and DHA over 48 h. Subjects were then randomised to one of three groups for 8 weeks before repeating the tracer study: (1) continued on same intake (control, n 5); (2) increased ALNA intake (10 g/d, n 4); (3) increased EPA+DHA intake (1.5 g/d, n 5). At baseline, apparent fractional conversion of labelled ALNA was: EPA 2.80, DPA 1.20 and DHA 0.04 %. After 8 weeks on the control diet, plasma lipid composition and [(13)C]ALNA conversion remained unchanged compared with baseline. The high-ALNA diet resulted in raised plasma triacylglycerol-EPA and -DPA concentrations and phosphatidylcholine-EPA concentration, whilst [(13)C]ALNA conversion was similar to baseline. The high-(EPA+DHA) diet raised plasma phosphatidylcholine-EPA and -DHA concentrations, decreased [(13)C]ALNA conversion to EPA (2-fold) and DPA (4-fold), whilst [(13)C]ALNA conversion to DHA was unchanged. The dietary interventions did not alter partitioning of ALNA towards beta-oxidation. The present results indicate ALNA conversion was down-regulated by increased product (EPA+DHA) availability, but was not up-regulated by increased substrate (ALNA) consumption. This suggests regulation of ALNA conversion may limit the influence of variations in dietary n-3 fatty acid intake on plasma lipid compositions.
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Affiliation(s)
- Graham C Burdge
- Institute of Human Nutrition, University of Southampton, UK.
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