Pravastatin accelerates ischemia-induced angiogenesis through AMP-activated protein kinase

Statins exert pleiotropic effects on the cardiovascular system, in part through an increase in nitric oxide (NO) bioavailability. In this study, we examined the role of pravastatin in ischemia-induced angiogenesis. Unilateral hindlimb ischemia was surgically induced in C57BL/6J mice. Phosphorylation of AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC) and endothelial NO synthase (eNOS) was increased in ischemic tissues. Furthermore, mice treated with pravastatin showed higher increases in phosphorylation than did untreated mice. Laser Doppler analysis has shown that pravastatin treatment accelerates the development of collateral vessels and angiogenesis in response to hindlimb ischemia. Capillary density in the ischemic hindlimb was also increased by pravastatin treatment. An in vitro study on human umbilical vein endothelial cells (HUVECs) revealed that pravastatin increased the phosphorylation of AMPK. Pravastatin-induced phosphorylation of eNOS, one of the downstreams of AMPK, was inhibited by compound C, an AMPK antagonist. The increased migration and tube formation of HUVECs by pravastatin were significantly blocked by compound C treatment. The accelerated angiogenesis by pravastatin after hindlimb ischemia was significantly reduced after treatment with compound C. Thus, ischemia induced AMPK phosphorylation in vivo. Furthermore, pravastatin could also activate AMPK in vivo and in vitro. Such phosphorylation results in eNOS activation and angiogenesis, which provide a novel explanation for one of the pleiotropic effects of statins that is beneficial for angiogenesis.