Ranolazine prevents pressure overload-induced cardiac hypertrophy and heart failure by restoring aberrant Na and Ca handling.

BACKGROUND

Cardiac hypertrophy and heart failure are characterized by increased late sodium current and abnormal Ca handling. Ranolazine, a selective inhibitor of the late sodium current, can reduce sodium accumulation and Ca overload. In this study, we investigated the effects of ranolazine on pressure overload-induced cardiac hypertrophy and heart failure in mice.

METHODS AND RESULTS

Inhibition of late sodium current with the selective inhibitor ranolazine suppressed cardiac hypertrophy and fibrosis and improved heart function assessed by echocardiography, hemodynamics, and histological analysis in mice exposed to chronic pressure overload induced by transverse aortic constriction (TAC). Ca imaging of ventricular myocytes from TAC mice revealed both abnormal SR Ca release and increased SR Ca leak. Ranolazine restored aberrant SR Ca handling induced by pressure overload. Ranolazine also suppressed Na overload induced in the failing heart, and restored Na -induced Ca overload in an sodium-calcium exchanger (NCX)-dependent manner. Ranolazine suppressed the Ca -dependent calmodulin (CaM)/CaMKII/myocyte enhancer factor-2 (MEF2) and CaM/CaMKII/calcineurin/nuclear factor of activated T-cells (NFAT) hypertrophy signaling pathways triggered by pressure overload. Pressure overload also prolonged endoplasmic reticulum (ER) stress leading to ER-initiated apoptosis, while inhibition of late sodium current or NCX relieved ER stress and ER-initiated cardiomyocyte apoptosis.

CONCLUSIONS

Our study demonstrates that inhibition of late sodium current with ranolazine improves pressure overload-induced cardiac hypertrophy and systolic and diastolic function by restoring Na and Ca handling, inhibiting the downstream hypertrophic pathways and ER stress. Inhibition of late sodium current may provide a new treatment strategy for cardiac hypertrophy and heart failure.