T. D. Turner, W. J. Meadus, P. D. Duff, D. C. Rolland, C. Mapiye, J. Church and M. E. R. Dugan
Posters: J Veterinar Sci Technolo
Adipose tissue is an active regulatory tissue producing cytokines with immunomodulating effects that can be influenced by fatty acids (FA). Conjugated linoleic acid (CLA), with c 9, t 11-CLA being the predominant isomer in ruminant products, and t10c12-CLA largely of industrial origin, purportedly have substantial anti-arithrogenic, anticarcinogenic and anti-obesity effects. The fate of CLA?s has not been investigated in adipose tissue, prompting investigations into effects on the FA profile. Mature 3T3- L1 cells were incubated with 70μM c 9, t 11- C LA, t 10, c 12-CLA or 18:2n-6. Gene expression (ΔΔCt) measured by rt-PCR at 48h and normalised to 18:2n-6 indicated both CLA isomers slightly increased PPARγ expression, which correspondingly induced a 1.7 and 2.4 fold increase in adipose FA binding protein (AFABP) expression for c 9t11- and t 10c12-CLA respectively. Expression of FA oxidase (Acox1) and leptin were increased more by t 10, c 12-CLA, corresponding to increased lipid mobilization and catabolism, whereas increased monocyte chemotactic protein (MCP-1) expression may be indicative of an inflammatory stress response to FA oxidation. Lipid profiles of cells harvested at 144h were analysed by GC-FID, and FA with conjugated bonds were separated and collected by Ag + -HPLC then analysed by GC-MS-EI to identify novel metabolites. Cultures incubated with c 9, t 11-CLA and 18:2n-6 had similar lipid content, whereas t 10, c 12-CLA induced a two-fold reduction. Conjugated diene metabolites with 16-, and 20-carbons were identified for c 9, t 11-CLA, similar t 10, c 12-CLA metabolites were also present, along with a 14-carbon diene. Previously unreported conjugated trienes assumed to be c 6, c 9, t 11/ c 6, t 10, c 12-18:3 and c 8, c 11, t 13/ c 8 t 12 c 14-20:3 were identified. Possible secondary effects of CLA isomer metabolites on gene expression of adipocytes require further investigation.
T.D. Turner performed the work with AAFC on a Visiting Fellowship funded by the Alberta Livestock and Meat Agency (ALMA) and current post- doctoral work is funded by Thompson River University. His work has focused on animal nutrition and lipidomics towards the nutraceutical properties of animal products, including over 20 peer-reviewed publications.