Glucose loading for heart failure protects the myocardium and improves physical function.

[Purpose] The purpose of this study was to investigate the effects of glucose intake on physical function in a heart failure rat model. [Materials and Methods] Five-week-old male Wistar rats were used for this study. Monocrotalin (40 mg/kg) was administered intraperitoneally to rats to induce heart failure. The rats were divided into two groups, control and MCT; the MCT group was further classified according to glucose concentration (0%, 10%, and 50%). [Results] Glucose intake during heart failure prevented the loss of body weight, skeletal muscle, and fat mass. Myocardial metabolism in heart failure was enhanced by hypoxia, which in turn, enhanced the glycolytic system. [Conclusion] Glucose loading suppressed cardiac hypertrophy and improved physical function in the heart failure rat model.

The Effects of Branched-Chain Amino Acids on the Akt/mTOR Pathway and Nebulin Protein in Joint Fixation-Induced Muscle Atrophy.

It is well known that branched-chain amino acids (BCAAs) promote protein synthesis in skeletal muscle and can cause muscle hypertrophy. However, it has also been reported that they may inhibit muscle atrophy induced by load-bearing and age-related changes. In this study, we investigated the effects of BCAA intake during joint fixation on the levels of protein kinase B (Akt), mammalian target of rapamycin (mTOR), and nebulin in a rat model of joint fixation. Akt and mTOR are signal factors of protein synthesis, whereas nebulin is a structural protein in the muscle. The effects of BCAAs on muscle atrophy were also investigated. The phosphorylation rate of mTOR was higher than that of Akt and increased with BCAA intake in the rat hind limb muscles (soleus) when the ankle joint was fixed. The relative level of nebulin and the phosphorylation rate of Neural Wiskott-Aldrich syndrome protein (N-WASP) also increased as a result of BCAA intake during fixation. This is important because nebulin and N-WASP are involved in the formation of the structure of sarcomere thin filaments. Furthermore, when the cross-sectional areas (CSAs) of different types of muscle fibers were measured during histological evaluation of muscle atrophy, it was found that the inhibitory effect of BCAA on muscle atrophy was higher in Type 1 fibers. Additionally, a positive correlation was found between nebulin level and the CSAs of the muscle fibers. It was found that there is a close relationship between the content of structural proteins and muscle atrophy.