A cis-9,trans-11-conjugated linoleic acid-rich oil reduces the outcome of atherogenic process in hyperlipidemic hamster

1 Université Paris, Orsay; 2 Institut National de la Santé et de la Recherche Médicale U465, Centre Biomédical des Cordeliers, Paris, France; 3 Lipid Nutrition, Loders Croklaan, Wormerweer, The Netherlands; and 4 UMR Institut National de la Santé et de la Recherche Médicale 476/Institut National de la Recherche Agronomique 1260, Faculté de Médecine, Marseille, France Submitted 8 February 2005 ; accepted in final form 17 March 2005 Conjugated linoleic acid (CLA) mixtures demonstrated antiatherogenic properties in several animal models, including hamsters, but the mechanism of action of the main food-derived CLA isomer is unknown in this species. This study thus focused on cis -9, trans -11-CLA (rumenic acid), and its effect was compared with that of fish oil, which is known to influence several aspects of atherogenesis. Syrian hamsters were fed (for 12 wk) diets containing 20% (wt/wt) butter fat (B diet) or the same diet augmented with either 1% (wt/wt) of a cis -9, trans -11-CLA-rich oil (BR diet) or 1% (wt/wt) fish oil (BF diet). The BR diet induced the lowest aortic lipid deposition (from –30% to –45%) among the butter oil-fed hamsters. In this group, plasma also displayed a reduced non-HDL-to-HDL-cholesterol ratio (21% less than in the butter oil group) and inflammatory serum amyloid A levels (70–80%) and an improvement of anti-oxidized LDL paraoxonase activity (all P < 0.05). Compared with the B group, the beneficial effects of the BR diet could be further explained in part by preventing the high VCAM-1 expression rate, increasing (30%) ATP-binding cassette subfamily A1 expression in the aorta, and downregulating expression of inflammatory-related genes (TNF- , IL-1 , and cyclooxygenase 2, 2- to 2.8-fold, P < 0.05). This effect was partly associated with an activation of peroxisome proliferator-activating receptor (PPAR)/liver X receptor (LXR)- signaling cascade. Interestingly, activation of PPAR/LXR- signaling was not observed in hamsters fed the BF diet, in which the early signs of atherogenesis were increased. In conclusion, this study demonstrated that milk fat-rich cis -9, trans -11-CLA reduces the atherogenic process in hyperlipidemic hamsters. fish oil; rumenic acid; atherosclerosis; risk factors Address for reprint requests and other correspondence: J. C. Martin, UMR Institut National de la Santé et de la Recherche Médicale 476/Institut National de la Recherche Agronomique 1260, Faculté de Médecine La Timone, 27 Bvd Jean Moulin, 13380 Marseille