1. A method of treating muscle damage, muscle injury, or muscle atrophy in a subject having spinal muscular atrophy, said method comprising administering a composition comprising a 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibitor to said subject in an amount effective to inhibit 15-PGDH, thereby treating said muscle damage, muscle injury, or muscle atrophy in said subject having spinal muscular atrophy.