Effect of Epidermal Growth Factor and Cyclosporin A on InterIeukin-8 Gene Expression in Human Aortic Smooth Muscle Cells

It was reported that accelerated allograft atherosclerosis is associated with usage of cyclosporin A (CsA). Although the immunosuppressive actions of CsA are extensively studied, the mechanisms of this adverse effect remains to be elucidated. We thus studied whether CsA affects the expression of interleukin (IL)-8 in the primary culture of human aortic smooth muscle cells (HASMC) since IL-8 recently has been shown to be a mitogen and a chemoattractant for vascular smooth muscle cells (VSMC). We also studied the effect of epidermal growth factor (EGF) on IL-8 expression because of its potent action of VSMC proliferation in the atherosclerotic lesion. Treatment of HASMC with CsA alone resulted in a significant increase in the IL-8 mRNA level. EGF also increased the mRNA level. CsA together with EGF further increased the IL-8 mRNA level. These results suggested that the CsA-dependent increase in IL-8 in VSMC could be one of the mechanisms for its induced accelerated allograft atherosclerosis.