title: Increased hypolipidemic benefits of cis-9, trans-11 conjugated linoleic acid in combination with trans-11 vaccenic acid in a rodent model of the metabolic syndrome, the JCR:LA-cp rat.
abstract: BACKGROUND
  Conjugated linoleic acid (cis-9, trans-11 CLA) and trans-11 vaccenic acid (VA) are found naturally in ruminant-derived foods. CLA has been shown to have numerous potential health related effects and has been extensively investigated. More recently, we have shown that VA has lipid-lowering properties associated with reduced hepatic lipidogenesis and chylomicron secretion in the JCR:LA-cp rat. The aim of this study was to evaluate potential additional hypolipidemic effects of purified forms of CLA and VA in an animal model of the metabolic syndrome (the JCR:LA-cp rat).
  
  
  METHODS
  Twenty four obese JCR:LA-cp rats were randomized and assigned to one of three nutritionally adequate iso-caloric diets containing 1% w/w cholesterol and 15% w/w fat for 16 wk: 1) control diet (CD), 2) 1.0% w/w cis-9, trans-11 CLA (CLA), 3) 1.0% w/w VA and 1% w/w cis-9, trans-11 CLA (VA+CLA). Lean rats were fed the CD to represent normolipidemic conditions.
  
  
  RESULTS
  Fasting plasma triglyceride (TG), total cholesterol and LDL-cholesterol concentrations were reduced in obese rats fed either the CLA diet or the VA+CLA diet as compared to the obese control group (p < 0.05, p < 0.001; p < 0.001, p < 0.01; p < 0.01, p < 0.001, respectively). The VA+CLA diet reduced plasma TG and LDL-cholesterol to the level of the normolipidemic lean rats and further decreased nonesterified fatty acids compared to the CLA diet alone. Interestingly, rats fed the VA+CLA diet had a higher food intake but lower body weight than the CLA fed group (P < 0.05). Liver weight and TG content were lower in rats fed either CLA (p < 0.05) or VA+CLA diets (p < 0.001) compared to obese control, consistent with a decreased relative protein abundance of hepatic acetyl-CoA carboxylase in both treatment groups (P < 0.01). The activity of citrate synthase was increased in liver and adipose tissue of rats fed, CLA and VA+CLA diets (p < 0.001) compared to obese control, suggesting increased mitochondrial fatty acid oxidative capacity.
  
  
  CONCLUSIONS
  We demonstrate that the hypolipidemic effects of chronic cis-9, trans-11 CLA supplementation on circulating dyslipidemia and hepatic steatosis are enhanced by the addition of VA in the JCR:LA-cp rat.
authors.affiliation: Metabolic and Cardiovascular Diseases Laboratory, University of Alberta, Edmonton, AB, T6G 2P5, Canada. spencer.proctor@ualberta.ca.
authors.forename: M Miriam
authors.initials: MM
authors.lastname: Jacome-Sosa
authors.forename: Jing
authors.initials: J
authors.lastname: Lu
authors.forename: Ye
authors.initials: Y
authors.lastname: Wang
authors.forename: Megan R
authors.initials: MR
authors.lastname: Ruth
authors.forename: David C
authors.initials: DC
authors.lastname: Wright
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Reaney
authors.forename: Jianheng
authors.initials: J
authors.lastname: Shen
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Field
authors.forename: Donna F
authors.initials: DF
authors.lastname: Vine
authors.forename: Spencer D
authors.initials: SD
authors.lastname: Proctor