Atorvastatin ameliorates lipid overload-induced mitochondrial dysfunction and myocardial hypertrophy by decreasing fatty acid oxidation through inactivation of the p-STAT3/CPT1 pathway

Although statins are shown to have cardiac pleiotropic effects independent of lowering cholesterol, the underlying mechanism remains unclear. Mitochondrial dysfunction induced by increased fatty acid oxidation (FAO) is the culprit in the development of cardiac hypertrophy and dysfunction. This study was to explore whether the cardiac pleiotropic effects of atorvastatin were associated with FAO regulation, with a specific focus on carnitine palmitoyltransferase 1 (CPT1). High-fat diet (HFD)-fed mice and palmitic acid (PA)-stimulated neonatal rat primary cardiomyocytes (NRCMs) were treated with atorvastatin, with or without FAO modulators, signal transducer and activator of transcription 3 (STAT3) agonist, and inhibitor. Atorvastatin (3 mg/kg) did not reduce serum cholesterol levels in HFD-fed mice but ameliorated mitochondrial dysfunction and cardiac hypertrophy. In vitro, atorvastatin and the FAO inhibitor alleviated PA-induced mitochondrial dysfunction and cardiomyocyte hypertrophy. However, the FAO enhancer eliminated atorvastatin's protective effects. Furthermore, atorvastatin decreased CPT1 and FAO levels and prevented STAT3 phosphorylation and nuclear translocation. STAT3 inhibitor had the same inhibitory effects as atorvastatin on CPT1, FAO levels, and cardiomyocyte hypertrophy, whereas STAT3 agonist disrupted these effects of atorvastatin. Our results demonstrate that atorvastatin decreases myocardial FAO by inactivating the p-STAT3/CPT1 signaling pathway, which improves lipid overload-induced mitochondrial dysfunction and cardiac hypertrophy in a cholesterol-independent manner. This is the first study to explore the cardiac pleiotropic effects of atorvastatin with respect to FAO. However, whether atorvastatin regulates FAO in the cardiac hypertrophy model induced by other variables has not been investigated in this work, and this is expected to be performed in the future.