Abstract 350: Atorvastatin Attenuates Pressure Overload-induced Cardiac Hypertrophy and Dysfunction Through Enhanced Autophagy

Abstract

Aims: Cardiac hypertrophy is a maladaptive change in response to pressure overload and is also an important risk for developing heart failure. We previously demonstrated that atorvastatin inhibits cardiac hypertrophy and remodeling in a mouse model of transverse aorta constriction (TAC). This study was designed to determine the regulation of atorvastatin on cardiac autophagy and its association with the development of cardiac hypertrophy and dysfunction in the mice TAC model. Methods and results: TAC or sham operations were performed in male C57/L6 mice at 8 weeks of age. Atorvastatin (50 mg/kg/day) or vehicle (normal saline) were administered daily by oral gavage to TAC mice (n=10 per group). Echocardiography and real-time PCR data showed that chronic atorvastatin treatment for four weeks significantly attenuated pressure overload-induced cardiac hypertrophy and dysfunction, as well as cardiac mRNA level of atrial natriuretic factor (ANF), a biomarker of cardiac hypertrophy and heart failure. After 4 weeks of TAC, results from electron microscopy and Western blot showed that cardiac autophagy was activated, evidenced by the increased expression of microtubule-associated protein-1 light chain 3-II (LC3-II), Beclin-1, caspase-3, and the formation of autophagosomes. Interestingly, cardiac autophagy was further increased by the treatment of atorvastatin for 4 weeks. Western blot analysis showed phosphorylated Akt and mammalian target of rapamycin (p-mTor) decreased in the heart of TAC versus sham mice, which were further decreased by atorvastatin treatment. Conclusions: These findings suggest that atorvastatin attenuates cardiac hypertrophy and dysfunction in TAC mice probably through its regulation on cardiac autophagy via Akt/mTor pathways.