MYOD1 and sarcopenia: However, it is necessary to confirm the importance of the AKT/mTOR/FoxO3a signaling pathway for the amelioration of sarcopenia, and also that of the expression of myogenic transcription factors, which are involved in myogenesis, such as myoblast determination protein 1 (MyoD), myocyte enhancer factor 2 (MEF-2), and myogenin [29].