title: α-Linolenic acid supplementation and exercise training reveal independent and additive responses on hepatic lipid accumulation in obese rats.
abstract: α-Linolenic acid (ALA) supplementation or exercise training can independently prevent hepatic lipid accumulation and reduced insulin signaling; however, this may occur through different mechanisms of action. In the current study, obese Zucker rats displayed decreased phospholipid (PL) content in association with hepatic lipid abundance, and therefore, we examined whether ALA and exercise training would prevent these abnormalities differently to reveal additive effects on the liver. To achieve this aim, obese Zucker rats were fed control diet alone or supplemented with ALA and were sedentary or exercise trained for 4 wk (C-Sed, ALA-Sed, C-Ex, and ALA-Ex). ALA-Sed rats had increased microsomal-triglyceride transfer protein (MTTP), a protein required for lipoprotein assembly/secretion, as well as modestly increased PL content in the absence of improvements in mitochondrial content, lipid accumulation, or insulin sensitivity. In contrast, C-Ex rats had increased mitochondrial content and insulin sensitivity; however, this corresponded with minimal improvements in PL content and hepatic lipid accumulation. Importantly, ALA-Ex rats demonstrated additive improvements in PL content and hepatic steatosis, which corresponded with increased mitochondrial content, MTTP and apolipoprotein B100 content, greater serum triacylglyceride, and insulin sensitivity. Overall, these data demonstrate additive effects of ALA and exercise training on hepatic lipid accumulation, as exercise training preferentially increased mitochondrial content, while ALA promoted an environment conducive for lipid secretion. These data highlight the potential for combination therapy to mitigate liver disease progression.
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and pmiotto@uoguelph.ca.
authors.forename: Paula M
authors.initials: PM
authors.lastname: Miotto
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Meaghan
authors.initials: M
authors.lastname: Horbatuk
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Ross
authors.initials: R
authors.lastname: Proudfoot
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Sarthak
authors.initials: S
authors.lastname: Matravadia
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Marica
authors.initials: M
authors.lastname: Bakovic
authors.affiliation: Department of Physiology, Medical University of Bialystok, Bialystok, Poland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Chabowski
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Graham P
authors.initials: GP
authors.lastname: Holloway
mesh_terms: D000818:Animals; D053299:Apolipoprotein B-100 / Q000378:metabolism; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D015153:Blotting, Western; D002352:Carrier Proteins / Q000819:agonists* / Q000378:metabolism; D003131:Combined Modality Therapy; D019587:Dietary Supplements; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D065626:Non-alcoholic Fatty Liver Disease / Q000209:etiology / Q000517:prevention & control*; D009765:Obesity / Q000178:diet therapy* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D010743:Phospholipids / Q000378:metabolism; D010805:Physical Conditioning, Animal; D011897:Random Allocation; D011924:Rats, Zucker; D014280:Triglycerides / Q000097:blood; D017962:alpha-Linolenic Acid / Q000627:therapeutic use*
chemical_list: D053299:Apolipoprotein B-100; D015415:Biomarkers; D002352:Carrier Proteins; D010743:Phospholipids; D014280:Triglycerides; C106092:microsomal triglyceride transfer protein; D017962:alpha-Linolenic Acid
keywords: hepatic steatosis; lipid secretion; mitochondrial capacity; phospholipid