MSTN and sarcopenia: CKD-associated sarcopenia, also referred to as uremic sarcopenia, shows a progressive loss of muscle function and is driven by a combination of uremic toxins (indoxyl sulfate), and hallmark cytokines associated with the inflammatory process, including IL-1, IL-6, and TNF-α, along with oxidative stress, leading to elevated myostatin levels that exacerbate muscle wasting [14,71] (p. 2).