MSTN and muscle atrophy: Pharmacologic treatments for muscle atrophy that have been studied in animal models and clinical trials include an anti-myostatin peptibody [21]; Stat3 inhibitor [22]; anabolic androgenic steroids such as nandrolone decanoate, a synthetic derivative of testosterone [23]; IGF-1 and its analogues [24]; an angiotensin-II receptor antagonist, losartan [25]; proteasome inhibitors [26, 27]; MURF1 inhibitor PO13222 [28]; a caspase inhibitor called X-linked inhibitor of apoptosis protein [3, 10]; and antisense oligonucleotides [29].