“…Our laboratory and others report that adult muscle fibers can grow in the absence of satellite cell fusion and myonuclear addition, indicating flexibility within the myonuclear domain. 18 , 19 Hypertrophy without increased myonuclear number has been demonstrated with mechanical, 6–8 , 10 , 11 , 66 pharmacological, 13 , 67–69 and genetic approaches, 68 , 70–74 although this finding is not universal, 4 , 12 , 13 , 75–79 which could be explained by a variety of factors. 5 , 19 In recent years, a deeper appreciation for the secretory function of muscle stem cells in general, 80–84 and satellite cells specifically 7 , 8 , 21 , 22 has emerged in the context of skeletal muscle remodeling, with evidence for EV communication between mononuclear cells.…”