Conjugated linoleic acid isomers inhibit platelet-derived growth factor-induced NF-κB transactivation and collagen formation in human vascular smooth muscle cells

Background Atherosclerosis is characterized by extensive thickening of the arterial intima partially resulting from deposition of collagen by vascular smooth muscle cells (SMCs). Polyunsaturated fatty acids stimulate collagen formation through NF-κB activation. Aim of the study The present study aimed to explore the effect of conjugated linoleic acids (CLAs) which are known to inhibit NF-κB activation on collagen formation by SMCs. Methods Vascular SMCs were cultured with 50 μmol/l of CLA isomers (c9t11-CLA, t10c12-CLA) or linoleic acid (LA) and analysed for collagen formation and NF-κB p50 transactivation. Results Treatment with CLA isomers but not LA significantly reduced PDGF-stimulated ³H] proline incorporation into cell layer protein of SMCs without altering cell proliferation. Simultaneous treatment with the PPARγ inhibitor T0070907 abrogated this effect. Treatment of SMCs with c9t11-CLA and t10c12-CLA significantly reduced PDGF-induced NF-κB p50 activation. Conclusions CLA isomers inhibit PDGF-stimulated collagen production by vascular SMCs, which is considered to be a hallmark of atherosclerosis, in a PPARγ-dependent manner. Whether inhibition of the NF-κB-pathway is of significance for the reduction of collagen formation by CLA isomers needs further investigation.