MSTN and sarcopenia: Aberrations in the IS‐induced pathway to sarcopenia (intracellular IS uptake through OATs, ROS generation, and regulation of TNF‐α, IL‐6, myostatin, and atrogin‐1) could have caused the null effect of AST‐120 on SMI and HGS and could explain the decrease in the proportion of patients with low muscle mass and sarcopenia in the REN group in this study.