Formation of conjugated linoleic acid metabolites in human vascular endothelial cells

Conjugated linoleic acids (CLAs) are bioactive lipid compounds showing anti-atherogenic actions in cell culture experiments and animal models of atherosclerosis without exact knowledge about the underlying mechanisms. CLAs were recently reported to be further metabolized to bioactive conjugated metabolites indicating that these metabolites are possibly involved in mediating the anti-atherogenic actions of CLA. Regarding the lack of information with respect to the formation of CLA metabolites in the vascular endothelium, which is strongly involved in the process of atherosclerosis, the present study aimed to explore the potential formation of CLA metabolites in vascular endothelial cells. The results from the present study show for the first time that the CLA isomers cis-9, trans-11 CLA and trans-10, cis-12 CLA are metabolized within endothelial cells to β-oxidation products such as CD16:2c7t9 and CD16:2t8c10 and elongation products such as CD20:2c11t13, CD20:2t12c14 as well as CD22:2c13t15 and CD22:2t14c16. Different CD16:2/CLA ratios observed between cells treated with different CLA isomers indicate that the metabolism of CLAs depends on the configuration of the conjugated double bonds. In conclusion, regarding the biological activity reported for CD20:2t12c14 and other metabolites of CLA, the present results indicate that metabolites of CLA are possibly also involved in mediating the anti-atherogenic actions of CLA.