Objective--We examined the inhibitory mechanisms of fluvastatin on FBS-induced vascular hypertrophy assessed by organ-cultured rat tail artery.

Methods and Results--After 5 days of culture with 10% FBS, hyperplastic morphological changes in the media layer were induced. Treatment with 1 µmol/L fluvastatin significantly inhibited these changes. In the FBS-cultured arteries, the protein expression ratio of -actin/-actin was significantly decreased, indicating the change to synthetic phenotype. Fluvastatin restored the decreased the expression ratio, and the addition of mevalonate (100 µmol/L) suppressed this recovery. In accordance with the synthetic morphological changes, the absolute force of contractions induced by stimuli was decreased. Fluvastatin treatment also restored the decreased contractility, and the addition of mevalonate suppressed this recovery. In the arteries cultured with FBS, extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38 mitogen-activated protein kinase (p38MAPK) phosphorylation were significantly increased. Fluvastatin inhibited these phosphorylations, and mevalonate prevented the action of fluvastatin.

Conclusion--These results suggest that fluvastatin inhibits vascular smooth muscle phenotype modulation to synthetic phenotype and proliferation by inhibiting the local metabolic pathway of cholesterol in smooth muscle cells, which inhibits hyperplastic changes in the vascular wall. The antihyperplastic actions by statins may be induced by inhibiting the ERK1/2 and p38MAPK activities, possibly through inhibition of prenylated Ras.