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Hennebelle M, Metherel AH, Kitson AP, Otoki Y, Yang J, Lee KSS, Hammock BD, Bazinet RP, Taha AY. Brain oxylipin concentrations following hypercapnia/ischemia: effects of brain dissection and dissection time. J Lipid Res 2019; 60:671-682. [PMID: 30463986 PMCID: PMC6399504 DOI: 10.1194/jlr.d084228] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 10/12/2018] [Indexed: 01/12/2023] Open
Abstract
PUFAs are precursors to bioactive oxylipin metabolites that increase in the brain following CO2-induced hypercapnia/ischemia. It is not known whether the brain-dissection process and its duration also alter these metabolites. We applied CO2 with or without head-focused microwave fixation for 2 min to evaluate the effects of CO2-induced asphyxiation, dissection, and dissection time on brain oxylipin concentrations. Compared with head-focused microwave fixation (control), CO2 followed by microwave fixation prior to dissection increased oxylipins derived from lipoxygenase (LOX), 15-hydroxyprostaglandin dehydrogenase (PGDH), cytochrome P450 (CYP), and soluble epoxide hydrolase (sEH) enzymatic pathways. This effect was enhanced when the duration of postmortem ischemia was prolonged by 6.4 min prior to microwave fixation. Brains dissected from rats subjected to CO2 without microwave fixation showed greater increases in LOX, PGDH, CYP and sEH metabolites compared with all other groups, as well as increased cyclooxygenase metabolites. In nonmicrowave-irradiated brains, sEH metabolites and one CYP metabolite correlated positively and negatively with dissection time, respectively. This study presents new evidence that the dissection process and its duration increase brain oxylipin concentrations, and that this is preventable by microwave fixation. When microwave fixation is not available, lipidomic studies should account for dissection time to reduce these artifacts.
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Affiliation(s)
- Marie Hennebelle
- Departments of Food Science and Technology University of California, Davis, Davis, CA
| | - Adam H Metherel
- Department of Nutritional Sciences Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Alex P Kitson
- Department of Nutritional Sciences Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Yurika Otoki
- Departments of Food Science and Technology University of California, Davis, Davis, CA
- Food and Biodynamic Laboratory Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Jun Yang
- Entomology and Nematology, University of California, Davis, Davis, CA
- College of Agriculture and Environmental Sciences, and Comprehensive Cancer Center University of California, Davis, Davis, CA
| | - Kin Sing Stephen Lee
- Departments of Food Science and Technology University of California, Davis, Davis, CA
- College of Agriculture and Environmental Sciences, and Comprehensive Cancer Center University of California, Davis, Davis, CA
| | - Bruce D Hammock
- Entomology and Nematology, University of California, Davis, Davis, CA
- College of Agriculture and Environmental Sciences, and Comprehensive Cancer Center University of California, Davis, Davis, CA
| | - Richard P Bazinet
- Department of Nutritional Sciences Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Ameer Y Taha
- Departments of Food Science and Technology University of California, Davis, Davis, CA
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Metherel AH, Lacombe RS, Aristizabal Henao JJ, Morin-Rivron D, Kitson AP, Hopperton KE, Chalil D, Masoodi M, Stark KD, Bazinet RP. Two weeks of docosahexaenoic acid (DHA) supplementation increases synthesis-secretion kinetics of n-3 polyunsaturated fatty acids compared to 8 weeks of DHA supplementation. J Nutr Biochem 2018; 60:24-34. [DOI: 10.1016/j.jnutbio.2018.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 06/25/2018] [Accepted: 07/02/2018] [Indexed: 11/26/2022]
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Lin L, Metherel AH, Kitson AP, Alashmali SM, Hopperton KE, Trépanier MO, Jones PJ, Bazinet RP. Dietary fatty acids augment tissue levels of n-acylethanolamines in n-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) knockout mice. J Nutr Biochem 2018; 62:134-142. [PMID: 30290332 DOI: 10.1016/j.jnutbio.2018.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 07/31/2018] [Accepted: 08/24/2018] [Indexed: 12/18/2022]
Abstract
N-acylethanolamines (NAEs) are lipid signaling mediators, which can be synthesized from dietary fatty acids via n-acylphosphatidylethanolamine-phospholipase D (NAPE-PLD) and in turn influence physiological outcomes; however, the roles of NAPE-PLD upon dietary fatty acid modulation are not fully understood. Presently, we examine if NAPE-PLD is necessary to increase NAEs in response to dietary fatty acid manipulation. Post-weaning male wild-type (C57Bl/6), NAPE-PLD (-/+) and NAPE-PLD (-/-) mice received isocaloric fat diets containing either beef tallow, corn oil, canola oil or fish oil (10% wt/wt from fat) for 9 weeks. Brain docosahexaenoic acid (DHA) levels were higher (P<.01) in NAPE-PLD (-/+) (10.01±0.31 μmol/g) and NAPE-PLD (-/-) (10.89±0.61 μmol/g) than wild-type (7.72±0.61 μmol/g) consuming fish oil. In NAPE-PLD (-/-) mice, brain docosahexaenoylethanolamide (DHEA) levels were higher (P<.01) after fish oil feeding suggesting that NAPE-PLD was not necessary for DHEA synthesis. Liver and jejunum arachidonoylethanolamide, 1,2-arachidonoylglycerol and DHEA levels reflected their corresponding fatty acid precursors suggesting that alternate pathways are involved in NAE synthesis. NAPE-PLD (-/-) mice had lower oleoylethanolamide levels in the jejunum and a leaner phenotype compared to wild-type mice. Overall, these results demonstrate that dietary fatty acid can augment tissue NAEs in the absence of NAPE-PLD.
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Affiliation(s)
- Lin Lin
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada
| | - Adam H Metherel
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada
| | - Alex P Kitson
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada
| | - Shoug M Alashmali
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada
| | | | | | - Peter J Jones
- Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada.
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Chalil A, Kitson AP, Aristizabal Henao JJ, Marks KA, Elzinga JL, Lamontagne-Kam DME, Chalil D, Badoud F, Mutch DM, Stark KD. PEMT, Δ6 desaturase, and palmitoyldocosahexaenoyl phosphatidylcholine are increased in rats during pregnancy. J Lipid Res 2017; 59:123-136. [PMID: 29167412 DOI: 10.1194/jlr.m080309] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/07/2017] [Indexed: 01/14/2023] Open
Abstract
DHA is important for fetal neurodevelopment. During pregnancy, maternal plasma DHA increases, but the mechanism is not fully understood. Using rats fed a fixed-formula diet (DHA as 0.07% total energy), plasma and liver were collected for fatty acid profiling before pregnancy, at 15 and 20 days of pregnancy, and 7 days postpartum. Phosphatidylethanolamine methyltransferase (PEMT) and enzymes involved in PUFA synthesis were examined in liver. Ad hoc transcriptomic and lipidomic analyses were also performed. With pregnancy, DHA increased in liver and plasma lipids, with a large increase in plasma DHA between day 15 and day 20 that was mainly attributed to an increase in 16:0/DHA phosphatidylcholine (PC) in liver (2.6-fold) and plasma (3.9-fold). Increased protein levels of Δ6 desaturase (FADS2) and PEMT at day 20 and increased Pemt expression and PEMT activity at day 15 suggest that during pregnancy, both DHA synthesis and 16:0/DHA PC synthesis are upregulated. Transcriptomic analysis revealed minor changes in the expression of genes related to phospholipid synthesis, but little insight on DHA metabolism. Hepatic PEMT appears to be the mechanism for increased plasma 16:0/DHA PC, which is supported by increased DHA biosynthesis based on increased FADS2 protein levels.
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Affiliation(s)
- Alan Chalil
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Alex P Kitson
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Kristin A Marks
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jason L Elzinga
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Daniel Chalil
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Flavia Badoud
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David M Mutch
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Ken D Stark
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Alashmali SM, Kitson AP, Lin L, Lacombe RJS, Bazinet RP. Maternal dietary n-6 polyunsaturated fatty acid deprivation does not exacerbate post-weaning reductions in arachidonic acid and its mediators in the mouse hippocampus. Nutr Neurosci 2017; 22:223-234. [PMID: 28903622 DOI: 10.1080/1028415x.2017.1372160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES The present study examines how lowering maternal dietary n-6 polyunsaturated fatty acids (PUFA) (starting from pregnancy) compared to offspring (starting from post-weaning) affect the levels of n-6 and n-3 fatty acids in phospholipids (PL) and lipid mediators in the hippocampus of mice. METHODS Pregnant mice were randomly assigned to consume either a deprived or an adequate n-6 PUFA diet during pregnancy and lactation (maternal exposure). On postnatal day (PND) 21, half of the male pups were weaned onto the same diet as their dams, and the other half were switched to the other diet for 9 weeks (offspring exposure). At PND 84, upon head-focused high-energy microwave irradiation, hippocampi were collected for PL fatty acid and lipid mediator analyses. RESULTS Arachidonic acid (ARA) concentrations were significantly decreased in both total PL and PL fractions, while eicosapentaenoic acid (EPA) concentrations were increased only in PL fractions upon n-6 PUFA deprivation of offspring, regardless of maternal exposure. Several ARA-derived eicosanoids were reduced, while some of the EPA-derived eicosanoids were elevated by n-6 PUFA deprivation in offspring. There was no effect of diet on docosahexaenoic acid (DHA) or DHA-derived docosanoids concentrations under either maternal or offspring exposure. DISCUSSION These results indicate that the maternal exposure to dietary n-6 PUFA may not be as important as the offspring exposure in regulating hippocampal ARA and some lipid mediators. Results from this study will be helpful in the design of experiments aimed at testing the significance of altering brain ARA levels over different stages of life.
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Affiliation(s)
- Shoug M Alashmali
- a Department of Nutritional Sciences, Faculty of Medicine , University of Toronto , Toronto , Canada
| | - Alex P Kitson
- a Department of Nutritional Sciences, Faculty of Medicine , University of Toronto , Toronto , Canada
| | - Lin Lin
- a Department of Nutritional Sciences, Faculty of Medicine , University of Toronto , Toronto , Canada
| | - R J Scott Lacombe
- a Department of Nutritional Sciences, Faculty of Medicine , University of Toronto , Toronto , Canada
| | - Richard P Bazinet
- a Department of Nutritional Sciences, Faculty of Medicine , University of Toronto , Toronto , Canada
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Metherel AH, Kitson AP, Domenichiello AF, Lacombe RJS, Hopperton KE, Trépanier MO, Alashmali SM, Lin L, Bazinet RP. Docosahexaenoic acid (DHA) accretion in the placenta but not the fetus is matched by plasma unesterified DHA uptake rates in pregnant Long Evans rats. Placenta 2017; 58:90-97. [PMID: 28962703 DOI: 10.1016/j.placenta.2017.08.072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/31/2017] [Accepted: 08/29/2017] [Indexed: 12/12/2022]
Abstract
Maternal delivery of docosahexaenoic acid (DHA, 22:6n-3) to the developing fetus via the placenta is required for fetal neurodevelopment, and is the only mechanism by which DHA can be accreted in the fetus. The aim of the current study was to utilize a balance model of DHA accretion combined with kinetic measures of serum unesterified DHA uptake to better understand the mechanism by which maternal DHA is delivered to the fetus via the placenta. Female rats maintained on a 2% α-linolenic acid diet free of DHA for 56 days were mated, and for balance analysis, sacrificed at 18 days of pregnancy, and fetus, placenta and maternal carcass fatty acid concentration were determined. For tissue DHA uptake, pregnant dams (14-18 days) were infused for 5 min with radiolabeled 14C-DHA and kinetic modeling was used to determine fetal and placental serum unesterified DHA uptake rates. DHA accretion rates in the fetus were determined to be 38 ± 2 nmol/d/g, 859 ± 100 nmol/d/litter and 74 ± 3 nmol/d/pup, which are all higher (P < 0.05) than the fetal serum unesterified DHA uptake rates of 16 ± 6 nmol/d/g, 239 ± 145 nmol/d/litter and 14 ± 8 nmol/d/pup. No differences (p > 0.05) in placental DHA accretion rates versus serum unesterified DHA uptake rates were observed as values varied only 6-35% between studies. No differences in placental accretion and uptake rates suggests that serum unesterified DHA is a significant pool for the maternal-placental transfer of DHA, and lower fetal DHA uptake compared to accretion supports remodeling of placental DHA for delivery to the fetus.
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Affiliation(s)
- Adam H Metherel
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada.
| | - Alex P Kitson
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - Anthony F Domenichiello
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - R J Scott Lacombe
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - Kathryn E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - Marc-Olivier Trépanier
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - Shoug M Alashmali
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - Lin Lin
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario M5S 3E2, Canada
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7
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Sivasubramaniyam T, Schroer SA, Li A, Luk CT, Shi SY, Besla R, Dodington DW, Metherel AH, Kitson AP, Brunt JJ, Lopes J, Wagner KU, Bazinet RP, Bendeck MP, Robbins CS, Woo M. Hepatic JAK2 protects against atherosclerosis through circulating IGF-1. JCI Insight 2017; 2:93735. [PMID: 28724798 DOI: 10.1172/jci.insight.93735] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 06/06/2017] [Indexed: 01/12/2023] Open
Abstract
Atherosclerosis is considered both a metabolic and inflammatory disease; however, the specific tissue and signaling molecules that instigate and propagate this disease remain unclear. The liver is a central site of inflammation and lipid metabolism that is critical for atherosclerosis, and JAK2 is a key mediator of inflammation and, more recently, of hepatic lipid metabolism. However, precise effects of hepatic Jak2 on atherosclerosis remain unknown. We show here that hepatic Jak2 deficiency in atherosclerosis-prone mouse models exhibited accelerated atherosclerosis with increased plaque macrophages and decreased plaque smooth muscle cell content. JAK2's essential role in growth hormone signalling in liver that resulted in reduced IGF-1 with hepatic Jak2 deficiency played a causal role in exacerbating atherosclerosis. As such, restoring IGF-1 either pharmacologically or genetically attenuated atherosclerotic burden. Together, our data show hepatic Jak2 to play a protective role in atherogenesis through actions mediated by circulating IGF-1 and, to our knowledge, provide a novel liver-centric mechanism in atheroprotection.
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Affiliation(s)
- Tharini Sivasubramaniyam
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Stephanie A Schroer
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Angela Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Department of Immunology
| | - Cynthia T Luk
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Sally Yu Shi
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Rickvinder Besla
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology
| | - David W Dodington
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Adam H Metherel
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Alex P Kitson
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Jara J Brunt
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Joshua Lopes
- Department of Laboratory Medicine and Pathobiology
| | - Kay-Uwe Wagner
- Eppley Institute for Research in Cancer and Allied Diseases and the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Michelle P Bendeck
- Department of Laboratory Medicine and Pathobiology.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Clinton S Robbins
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Department of Immunology.,Department of Laboratory Medicine and Pathobiology
| | - Minna Woo
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science.,Department of Immunology.,Division of Endocrinology and Metabolism, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
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Hennebelle M, Zhang Z, Metherel AH, Kitson AP, Otoki Y, Richardson CE, Yang J, Lee KSS, Hammock BD, Zhang L, Bazinet RP, Taha AY. Linoleic acid participates in the response to ischemic brain injury through oxidized metabolites that regulate neurotransmission. Sci Rep 2017; 7:4342. [PMID: 28659576 PMCID: PMC5489485 DOI: 10.1038/s41598-017-02914-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/20/2017] [Indexed: 12/15/2022] Open
Abstract
Linoleic acid (LA; 18:2 n-6), the most abundant polyunsaturated fatty acid in the US diet, is a precursor to oxidized metabolites that have unknown roles in the brain. Here, we show that oxidized LA-derived metabolites accumulate in several rat brain regions during CO2-induced ischemia and that LA-derived 13-hydroxyoctadecadienoic acid, but not LA, increase somatic paired-pulse facilitation in rat hippocampus by 80%, suggesting bioactivity. This study provides new evidence that LA participates in the response to ischemia-induced brain injury through oxidized metabolites that regulate neurotransmission. Targeting this pathway may be therapeutically relevant for ischemia-related conditions such as stroke.
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Affiliation(s)
- Marie Hennebelle
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Zhichao Zhang
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Adam H Metherel
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, ON, Canada
| | - Alex P Kitson
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, ON, Canada
| | - Yurika Otoki
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
- Food and Biodynamic Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan
| | - Christine E Richardson
- Department of Nutrition, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Jun Yang
- Department of Entomology and Nematology, College of Agriculture and Environmental Sciences and Comprehensive Cancer Center, Medical Center, University of California, Davis, CA, USA
| | - Kin Sing Stephen Lee
- Department of Entomology and Nematology, College of Agriculture and Environmental Sciences and Comprehensive Cancer Center, Medical Center, University of California, Davis, CA, USA
| | - Bruce D Hammock
- Department of Entomology and Nematology, College of Agriculture and Environmental Sciences and Comprehensive Cancer Center, Medical Center, University of California, Davis, CA, USA
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, ON, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, ON, Canada
| | - Ameer Y Taha
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA.
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Metherel AH, Kitson AP, Domenichiello AF, Lacombe RJS, Hopperton KE, Trépanier MO, Alashmali SM, Lin L, Bazinet RP. Maternal liver docosahexaenoic acid (DHA) stores are increased via higher serum unesterified DHA uptake in pregnant long Evans rats. J Nutr Biochem 2017. [PMID: 28628798 DOI: 10.1016/j.jnutbio.2017.05.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Maternal docosahexaenoic acid (DHA, 22:6n-3) supplies the developing fetus during pregnancy; however, the mechanisms are unclear. We utilized pregnant rats to determine rates of DHA accretion, tissue unesterified DHA uptake and whole-body DHA synthesis-secretion. Female rats maintained on a DHA-free, 2% α-linolenic acid diet were either:1) sacrificed at 56 days for baseline measures, 2) mated and sacrificed at 14-18 days of pregnancy or 3) or sacrificed at 14-18 days as age-matched virgin controls. Maternal brain, adipose, liver and whole body fatty acid concentrations was determined for balance analysis, and kinetic modeling was used to determine brain and liver plasma unesterified DHA uptake and whole-body DHA synthesis-secretion rates. Total liver DHA was significantly higher in pregnant (95±5 μmol) versus non-pregnant (49±5) rats with no differences in whole-body DHA synthesis-secretion rates. However, liver uptake of plasma unesterified DHA was 3.8-fold higher in pregnant animals compared to non-pregnant controls, and periuterine adipose DHA was lower in pregnant (0.89±0.09 μmol/g) versus non-pregnant (1.26±0.06) rats. In conclusion, higher liver DHA accretion during pregnancy appears to be driven by higher unesterified DHA uptake, potentially via DHA mobilization from periuterine adipose for delivery to the fetus during the brain growth spurt.
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Affiliation(s)
- Adam H Metherel
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2.
| | - Alex P Kitson
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - Anthony F Domenichiello
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - R J Scott Lacombe
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - Kathryn E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - Marc-Olivier Trépanier
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - Shoug M Alashmali
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - Lin Lin
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College St., Toronto, Ontario, Canada, M5S 3E2
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10
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Domenichiello AF, Kitson AP, Metherel AH, Chen CT, Hopperton KE, Stavro PM, Bazinet RP. Whole-Body Docosahexaenoic Acid Synthesis-Secretion Rates in Rats Are Constant across a Large Range of Dietary α-Linolenic Acid Intakes. J Nutr 2017; 147:37-44. [PMID: 27852871 DOI: 10.3945/jn.116.232074] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/22/2016] [Accepted: 10/18/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Docosahexaenoic acid (DHA) is an ω-3 (n-3) polyunsaturated fatty acid (PUFA) thought to be important for brain function. Although the main dietary source of DHA is fish, DHA can also be synthesized from α-linolenic acid (ALA), which is derived from plants. Enzymes involved in DHA synthesis are also active toward ω-6 (n-6) PUFAs to synthesize docosapentaenoic acid n-6 (DPAn-6). It is unclear whether DHA synthesis from ALA is sufficient to maintain brain DHA. OBJECTIVE The objective of this study was to determine how different amounts of dietary ALA would affect whole-body DHA and DPAn-6 synthesis rates. METHODS Male Long-Evans rats were fed an ALA-deficient diet (ALA-D), an ALA-adequate (ALA-A) diet, or a high-ALA (ALA-H) diet for 8 wk from weaning. Dietary ALA concentrations were 0.07%, 3%, and 10% of the fatty acids, and ALA was the only dietary PUFA that differed between the diets. After 8 wk, steady-state stable isotope infusion of labeled ALA and linoleic acid (LA) was performed to determine the in vivo synthesis-secretion rates of DHA and DPAn-6. RESULTS Rats fed the ALA-A diet had an ∼2-fold greater capacity to synthesize DHA than did rats fed the ALA-H and ALA-D diets, and a DHA synthesis rate that was similar to that of rats fed the ALA-H diet. However, rats fed the ALA-D diet had a 750% lower DHA synthesis rate than rats fed the ALA-A and ALA-H diets. Despite enrichment into arachidonic acid, we did not detect any labeled LA appearing as DPAn-6. CONCLUSIONS Increasing dietary ALA from 3% to 10% of fatty acids did not increase DHA synthesis rates, because of a decreased capacity to synthesize DHA in rats fed the ALA-H diet. Tissue concentrations of DPAn-6 may be explained at least in part by longer plasma half-lives.
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Affiliation(s)
| | - Alex P Kitson
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada; and
| | - Adam H Metherel
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada; and
| | - Chuck T Chen
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada; and
| | - Kathryn E Hopperton
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada; and
| | | | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Toronto, Canada; and
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11
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Metherel AH, Domenichiello AF, Kitson AP, Lin YH, Bazinet RP. Serum n-3 Tetracosapentaenoic Acid and Tetracosahexaenoic Acid Increase Following Higher Dietary α-Linolenic Acid but not Docosahexaenoic Acid. Lipids 2016; 52:167-172. [DOI: 10.1007/s11745-016-4223-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/09/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Adam H. Metherel
- ; Department of Nutritional Sciences, Faculty of Medicine; University of Toronto; 150 College St., Room 307, Fitzgerald Building Toronto ON M5S 3E2 Canada
| | - Anthony F. Domenichiello
- ; Department of Nutritional Sciences, Faculty of Medicine; University of Toronto; 150 College St., Room 307, Fitzgerald Building Toronto ON M5S 3E2 Canada
| | - Alex P. Kitson
- ; Department of Nutritional Sciences, Faculty of Medicine; University of Toronto; 150 College St., Room 307, Fitzgerald Building Toronto ON M5S 3E2 Canada
| | - Yu-Hong Lin
- ; Section of Nutritional Neurosciences, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism; National Institutes of Health; Bethesda MD USA
| | - Richard P. Bazinet
- ; Department of Nutritional Sciences, Faculty of Medicine; University of Toronto; 150 College St., Room 307, Fitzgerald Building Toronto ON M5S 3E2 Canada
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12
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Domenichiello AF, Kitson AP, Chen CT, Trépanier MO, Stavro PM, Bazinet RP. The effect of linoleic acid on the whole body synthesis rates of polyunsaturated fatty acids from α-linolenic acid and linoleic acid in free-living rats. J Nutr Biochem 2016; 30:167-76. [DOI: 10.1016/j.jnutbio.2015.11.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/07/2015] [Accepted: 11/20/2015] [Indexed: 11/30/2022]
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13
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Kitson AP, Metherel AH, Chen CT, Domenichiello AF, Trépanier MO, Berger A, Bazinet RP. Effect of dietary docosahexaenoic acid (DHA) in phospholipids or triglycerides on brain DHA uptake and accretion. J Nutr Biochem 2016; 33:91-102. [PMID: 27135386 DOI: 10.1016/j.jnutbio.2016.02.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/27/2016] [Accepted: 02/11/2016] [Indexed: 11/28/2022]
Abstract
Tracer studies suggest that phospholipid DHA (PL-DHA) more effectively targets the brain than triglyceride DHA (TAG-DHA), although the mechanism and whether this translates into higher brain DHA concentrations are not clear. Rats were gavaged with [U-(3)H]PL-DHA and [U-(3)H]TAG-DHA and blood sampled over 6h prior to collection of brain regions and other tissues. In another experiment, rats were supplemented for 4weeks with TAG-DHA (fish oil), PL-DHA (roe PL) or a mixture of both for comparison to a low-omega-3 diet. Brain regions and other tissues were collected, and blood was sampled weekly. DHA accretion rates were estimated using the balance method. [U-(3)H]PL-DHA rats had higher radioactivity in cerebellum, hippocampus and remainder of brain, with no differences in other tissues despite higher serum lipid radioactivity in [U-(3)H]TAG-DHA rats. TAG-DHA, PL-DHA or a mixture were equally effective at increasing brain DHA. There were no differences between DHA-supplemented groups in brain region, whole-body, or tissue DHA accretion rates except heart and serum TAG where the PL-DHA/TAG-DHA blend was higher than TAG-DHA. Apparent DHA β-oxidation was not different between DHA-supplemented groups. This indicates that more labeled DHA enters the brain when consumed as PL; however, this may not translate into higher brain DHA concentrations.
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Affiliation(s)
- Alex P Kitson
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, M5S3E2, Canada
| | - Adam H Metherel
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, M5S3E2, Canada
| | - Chuck T Chen
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, M5S3E2, Canada
| | | | - Marc-Olivier Trépanier
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, M5S3E2, Canada
| | - Alvin Berger
- Arctic Nutrition AS, NO-6155, Ørsta, Norway; Department of Food Science & Nutrition, University of Minnesota, St. Paul, MN, 55108-1038, USA
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, M5S3E2, Canada.
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14
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Kitson AP, Marks KA, Aristizabal Henao JJ, Tupling AR, Stark KD. Prevention of hyperphagia prevents ovariectomy-induced triacylglycerol accumulation in liver, but not plasma. Nutr Res 2015; 35:1085-94. [PMID: 26475180 DOI: 10.1016/j.nutres.2015.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 09/17/2015] [Accepted: 09/21/2015] [Indexed: 12/13/2022]
Abstract
Menopause is associated with higher plasma and liver triacylglycerol (TAG) and increased risk for cardiovascular disease. Lowering TAG in menopause may be beneficial; however, the mechanism underlying menopause-induced TAG accumulation is not clear. Ovariectomy is a model for menopause and is associated with metabolic alterations and hyperphagia. This study investigated the role of hyperphagia in ovariectomy-induced increases in blood and tissue TAG, as well as differences in lipid metabolism enzymes and resting metabolic measures. It was hypothesized that prevention of hyperphagia would restore blood and tissue TAG, enzyme expression, and metabolic measures to eugonadal levels. Ovariectomized rats were fed ad libitum (OVX + AL) or pair-fed (OVX + PF) relative to sham-operated rats (SHAM) to prevent hyperphagia. OVX + AL had higher TAG concentrations in liver and plasma than SHAM (60% and 50%, respectively), and prevention of hyperphagia in OVX + PF normalized TAG concentrations to SHAM levels in liver, but not plasma. OVX + AL also had 141% higher hepatic stearoyl-CoA desaturase 1 which was almost completely normalized to SHAM levels by pair-feeding, suggesting normalization of hepatic lipid storage. In contrast, skeletal muscle carnitine palmitoyl transferase 1 was 40% lower in OVX + AL than SHAM and was intermediate in OVX + PF, suggesting lower muscle fatty acid oxidation that may underlie the higher plasma TAG in OVX. No differences were seen in energy expenditure, VO2, or VCO2. Overall, this study indicates that prevention of hyperphagia resulting from ovarian hormone withdrawal normalizes hepatic TAG to eugonadal levels but has no effect on ovariectomy-induced increases in plasma TAG.
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Affiliation(s)
- Alex P Kitson
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1
| | - Kristin A Marks
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1
| | | | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1
| | - Ken D Stark
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1.
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15
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Domenichiello AF, Kitson AP, Bazinet RP. Is docosahexaenoic acid synthesis from α-linolenic acid sufficient to supply the adult brain? Prog Lipid Res 2015; 59:54-66. [DOI: 10.1016/j.plipres.2015.04.002] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 04/09/2015] [Indexed: 12/13/2022]
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16
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Mason JK, Kharotia S, Wiggins AKA, Kitson AP, Chen J, Bazinet RP, Thompson LU. 17β-Estradiol Increases Liver and Serum Docosahexaenoic Acid in Mice Fed Varying Levels of α-Linolenic Acid. Lipids 2014; 49:745-56. [DOI: 10.1007/s11745-014-3913-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/11/2014] [Indexed: 01/25/2023]
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17
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Kitson AP, Marks KA, Shaw B, Mutch DM, Stark KD. Treatment of ovariectomized rats with 17β-estradiol increases hepatic delta-6 desaturase enzyme expression and docosahexaenoic acid levels in hepatic and plasma phospholipids. Prostaglandins Leukot Essent Fatty Acids 2013; 89:81-8. [PMID: 23764042 DOI: 10.1016/j.plefa.2013.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/10/2013] [Accepted: 05/17/2013] [Indexed: 01/25/2023]
Abstract
Higher docosahexaenoic acid (DHA) in females compared with males suggests ovarian hormones increase DHA production. Eight-week old rats were ovariectomized or sham operated (SHAM), and ovariectomized rats were treated with implanted pellets providing 17β-estradiol (OVX+E), progesterone (OVX+P), both (OVX+PE) or neither (OVX) for 14 days. Immunoblot and fatty acid analysis were performed on all samples, and microarray analysis was performed on OVX and SHAM groups. Increased Δ6-desaturase in OVX relative to SHAM was observed by microarray (12% higher) and immunoblot (31% higher). OVX+E and OVX+PE rats had 39% and 42% higher Δ6-desaturase content, respectively, compared with OVX. OVX+E and OVX+PE also increased phospholipid DHA concentrations in liver (increase of 34% and 40%, respectively) and plasma (increase of 70% and 74%, respectively) relative to OVX. Progesterone exerted no effect on Δ6-desaturase or DHA. These results indicate that 17β-estradiol increases DHA through increased Δ6-desaturase, possibly explaining sex differences in DHA.
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Affiliation(s)
- Alex P Kitson
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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Marks KA, Kitson AP, Shaw B, Mutch DM, Stark KD. Stearoyl-CoA desaturase 1, elongase 6 and their fatty acid products and precursors are altered in ovariectomized rats with 17β-estradiol and progesterone treatment. Prostaglandins Leukot Essent Fatty Acids 2013; 89:89-96. [PMID: 23777599 DOI: 10.1016/j.plefa.2013.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/09/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
Abstract
Sex differences in monounsaturated fatty acid (MUFA) levels suggest ovarian hormones may affect MUFA biosynthesis. Sprague-Dawley rats (8 weeks of age) were ovariectomized or sham operated with ovariectomized rats implanted with a constant-release hormone pellet providing 17β-estradiol, progesterone, both or neither at 10 weeks of age. After 14 days, rats were fasted overnight and sacrificed to collect plasma and livers for analysis. Hepatic stearoyl-CoA desaturase (SCD1) expression was unchanged between ovariectomized and sham controls, as determined by microarray and immunoblotting. However, SCD1 protein was increased in rats treated with estradiol plus progesterone. Elongase 6 protein levels were increased with 17β-estradiol treatment compared with sham. Rats treated with 17β-estradiol and 17β-estradiol plus progesterone had increased 16:0, 18:0, 16:1n-7 and 18:1n-7 in hepatic and plasma phospholipids. Ovarian hormones appear to be involved with MUFA biosynthesis, but the relationship appears complex and involves elongase 6 and SCD1.
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Affiliation(s)
- Kristin A Marks
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada, N2L 3G1
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Kitson AP, Smith TL, Marks KA, Stark KD. Tissue-specific sex differences in docosahexaenoic acid and Δ6-desaturase in rats fed a standard chow diet. Appl Physiol Nutr Metab 2012; 37:1200-11. [PMID: 23050796 DOI: 10.1139/h2012-103] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Docosahexaenoic acid (DHA, 22:6n-3) is higher in the blood and tissues of females relative to males, but the underlying mechanism is not clear. The present study examined the expression of enzymes involved in the biosynthesis of DHA from short-chain n-3 polyunsaturated fatty acids in male and female rats (n = 6 for each sex). Rats were maintained on an AIN-93G diet and sacrificed at 14 weeks of age after an overnight fast. Plasma, erythrocytes, liver, heart, and brain were collected for fatty acid composition analysis and the determination of enzyme and transcription factor expression by RT-PCR and immunoblotting. Females had higher DHA concentrations in the total lipids of liver, plasma, erythrocyte, and heart (53%, 75%, 36%, and 25% higher, respectively, compared with males) with no sex differences in brain DHA concentrations. The mRNA content of Δ5-desaturase, Δ6-desaturase, and elongase 2 was 1.0-, 1.4-, and 1.1-fold higher, respectively, in the livers of female rats compared with males, with no differences in the hearts or brains. The protein content of Δ6-desaturase was also higher in females. Higher hepatic mRNA of sterol-regulatory element-binding protein 1-c and estrogen receptor α in the females suggests that lipogenic and estrogen signaling mechanisms are involved. The sex difference in DHA concentration is tissue specific and is associated with higher Δ6-desaturase expression in females relative to males, which appears to be limited to the liver.
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Affiliation(s)
- Alex P Kitson
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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20
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Kitson AP, Stark KD, Duncan RE. Enzymes in brain phospholipid docosahexaenoic acid accretion: a PL-ethora of potential PL-ayers. Prostaglandins Leukot Essent Fatty Acids 2012; 87:1-10. [PMID: 22749739 DOI: 10.1016/j.plefa.2012.06.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 05/30/2012] [Accepted: 06/01/2012] [Indexed: 10/28/2022]
Abstract
Neural tissue is highly enriched in docosahexaenoic acid (DHA) that is primarily found in the sn-2 position of ethanolamine-containing phospholipids and plasmalogens. Current knowledge on the activity of enzymes in brain phospholipid synthesis does not fully explain this composition and stereospecificity. It is likely that a host of enzyme-mediated processes play roles in brain DHA accumulation to develop this unique enrichment and phospholipid profile. This review examines current knowledge on the spectrum of enzymes that may be involved in brain DHA uptake and utilization in the synthesis and remodeling of phospholipids. It also highlights gaps in that knowledge, including missing information on the activity of known brain enzymes towards DHA as a substrate, and missing identities of brain enzymes that catalyze orphan reactions utilizing DHA for phospholipid formation.
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Affiliation(s)
- Alex P Kitson
- University of Waterloo, Department of Kinesiology, Faculty of Applied Health Sciences, Waterloo, Ontario, Canada N2L 3G1
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21
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Kitson AP, Stroud CK, Stark KD. Elevated production of docosahexaenoic acid in females: potential molecular mechanisms. Lipids 2010; 45:209-24. [PMID: 20151220 DOI: 10.1007/s11745-010-3391-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 01/15/2010] [Indexed: 01/25/2023]
Abstract
Observational evidence suggests that in populations consuming low levels of n-3 highly unsaturated fatty acids, women have higher blood levels of docosahexaenoic acid (DHA; 22:3n-6) as compared with men. Increased conversion of alpha-linolenic acid (ALA; 18:3n-3) to DHA by females has been confirmed in fatty acid stable isotope studies. This difference in conversion appears to be associated with estrogen and some evidence indicates that the expression of enzymes involved in synthesis of DHA from ALA, including desaturases and elongases, is elevated in females. An estrogen-associated effect may be mediated by peroxisome proliferator activated receptor-alpha (PPARalpha), as activation of this nuclear receptor increases the expression of these enzymes. However, because estrogens are weak ligands for PPARalpha, estrogen-mediated increases in PPARalpha activity likely occur through an indirect mechanism involving membrane-bound estrogen receptors and estrogen-sensitive G-proteins. The protein kinases activated by these receptors phosphorylate and increase the activity of PPARalpha, as well as phospholipase A(2) and cyclooxygenase 2 that increase the intracellular concentration of PPARalpha ligands. This review will outline current knowledge regarding elevated DHA production in females, as well as highlight interactions between estrogen signaling and PPARalpha activity that may mediate this effect.
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Affiliation(s)
- Alex P Kitson
- Laboratory of Nutritional and Nutraceutical Research, Department of Kinesiology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
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Kitson AP, Patterson AC, Izadi H, Stark KD. Pan-frying salmon in an eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) enriched margarine prevents EPA and DHA loss. Food Chem 2009. [DOI: 10.1016/j.foodchem.2008.10.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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