Conjugated linoleic acid (cis-9, trans-11 isomer) modulated tnf-α induced cell adhesion molecules expression in human umbilical vein endothelial cells (HUVEC)

Conjugated linoleic acid (CLA) is a polyunsaturated fatty acid (PUFA) that has been shown in recent years to have numerous potential benefits for human health. The vascular cell adhesion molecules play principal role in inflammatory diseases. Blocking the expression of these molecules or preventing their interaction with the receptors has been shown to be important in controlling various inflammatory diseases. However, the effect of CLA on endothelial cell adhesion molecules is unknown. We investigated the effects of cis-9, trans-11 Isomer of CLA on expression of intracellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial selectin (E-selectin) in HUVECs and comparison with, linoleic acid (LA). Endothelial cells co-incubated with or without TNF-α (0.001µg/ml) in the presence of LA or CLA (100µM/L) for 16-h before assessing the expression of adhesion molecules. The expression of adhesion molecules in HUVEC was assayed by ELISA and RT-PCR technique. CLA but not LA, decreased VCAM-1 and ICAM-1 expression in both mRNA and soluble levels in TNF-α activated cells (P<0.001). Furthermore, CLA modulated mRNA concentration of E-selectin, without any effect in soluble level of this molecule (P> 0.05). While LA didn’t show significant effect on TNF-α induced expression of adhesion molecules, a progressively increasing inhibitory activity was observed, for CLA. Therefore, CLA could be used as a novel agent for controlling various pathological conditions associated with up-regulation of inflammatory adhesion molecules at least in HUVECs. The role of CLA in the modulation of inflammation in vivo requires further study.