Lower and higher dietary intake of branched-chain amino acids impact cardiac structure and functions in high-fat fed LDLR -/- mice

Introduction: Elevation of dietary branched-chain amino acids (BCAAs) is regarded as a risk factor for heart failure. However, exposure to lower or higher levels of BCAAs on cardiac structure and function remained unclear. Mthods: The male C57BL/6J LDLR ^−/− mice were divided into 4 groups (n = 6) as feeding standard diet, high-fat diet, high-fat diet with low BCAAs, and high-fat diet with high BCAAs for 24 weeks. They underwent echocardiography after 12 and 24 weeks of dietary intervention. Then the mice were sacrificed and the heart organs were harvested for histological examination. Results The results showed that low or high nutritional BCAAs intake possessed different phenotypes on cardiac structure and function. Reduced BCAAs intake caused edema and a smaller inner diameter of the hearts in mice, while high BCAAs intake caused thinning and a larger inner diameter of the hearts. Pathological results showed that reducing the intake of BCAAs caused swelling of cardiomyocytes, loose fibers, and fragmentation of myocardial mitochondria. In contrast, higher intake of BCAAs increased the formation of lipid droplets and giant mitochondria. Conclusion Either decreased or increased dietary BCAAs intake induced negative effects on heart structure and function. The present research findings help the understanding of nutritional BCAAs intake at low or high levels related to pathological changes in the heart.