HMG-CoA reductase inhibitors reduce interleukin-6 synthesis in human vascular smooth muscle cells.

Interleukin-6 (IL-6) is a key molecule in chronic inflammation and has been implicated in the progression of atherosclerosis. HMG-CoA reductase inhibitors (statins) may reduce the cardiovascular risk and vulnerability of atherosclerotic plaque through nonlipid as well as lipid-lowering mechanisms, but their anti-inflammatory effects on the vascular tissue have not been fully elucidated. We investigated the effects of fluvastatin on IL-6 synthesis in human vascular smooth muscle cells (VSMCs). Addition of fluvastatin decreased IL-6 synthesis in VSMCs in a time (0-24 hours)- and dose (10(-8)-10(-5) mol/L)-dependent manner. Fluvastatin also decreased IL-6 mRNA expression in VSMCs. The effects of fluvastatin on IL-6 expression were completely reversed in the presence of mevalonate or geranylgeranyl-pyrophosphate, but not squalene. Inhibition of Rho by C3 exoenzyme or Rho kinase by Y-27632 significantly decreased IL-6 expression in VSMCs. In conclusion, fluvastatin decreases IL-6 synthesis in human VSMCs through inhibition of Rho pathway. These findings suggested that reduction of IL-6 expression by statins may partially explain their therapeutic effects in patients with coronary artery disease.