Aim: Statins have a protective impact against cardiovascular diseases through not only lipid-lowering effects but also pleiotropic effects, including activation of the endothelial nitric oxide synthase (eNOS) system. We aimed to clarify the protective effects of a statin against atherogenesis and ischemia in eNOS－/－ mice.
Methods: Study 1. eNOS－/－ Apolipoprotein E (ApoE)－/－ mice were treated with a vehicle or pitavastatin (0.3 mg/kg/day) for 4 weeks. Study 2. eNOS－/－ mice were also treated with a vehicle or the same dose of pitavastatin for 2 weeks prior to hind-limb ischemia.
Results: In Study 1, pitavastatin attenuated plaque formation and medial fibrosis of the aortic root with decreased macrophage infiltration in eNOS－/－ ApoE－/－ mice. PCR array analysis showed reductions in aortic gene expression of proatherogenic factors, including Ccl2 and Ccr2 in pitavastatin-treated double mutant mice. In addition, pitavastatin activated not only atherogenic p38MAPK and JNK but also anti-atherogenic ERK1/2 and ERK5 in the aorta of the double mutant mice. In Study 2, pitavastatin prolonged hind-limb survival after the surgery with increased BCL2-to-BAX protein ratio and inactivated JNK. Enhanced expression of anti-apoptotic genes, including Vegf, Api5, Atf5, Prdx2, and Dad1, was observed in the ischemic limb of pitavastatin-treated eNOS－/－ mice. Furthermore, pitavastatin activated both aortic and skeletal muscle AMPK in the eNOS-deficient vascular injury models.
Conclusion: Pitavastatin exerts eNOS-independent protective effects against atherogenesis and hind-limb ischemia in mice, which may occur via modifications on key molecules such as AMPK and diverse molecules.
Keywords: Atherogenesis; Ischemia; Pitavastatin; Pleiotropic effect; eNOS.