Recently, adipose tissue-derived stem cells (ASCs) were emerged as an alternative, abundant, and easily accessible source of stem cell therapy. Previous studies revealed losartan (an angiotensin II type I receptor blocker) treatment promoted the healing of skeletal muscle by attenuation of the TGF-β signaling pathway, which inhibits muscle differentiation. Therefore, we hypothesized that a combined therapy using ASCs and losartan might dramatically improve the muscle remodeling after muscle injury. To determine the combined effect of losartan with ASC transplantation, we created a muscle laceration mouse model. EGFP-labeled ASCs were locally transplanted to the injured gastrocnemius muscle after muscle laceration. The dramatic muscle regeneration and the remarkably inhibited muscular fibrosis were observed by combined treatment. Transplanted ASCs fused with the injured or differentiating myofibers. Myotube formation was also enhanced by ASC⁺ satellite coculture and losartan treatment. Thus, the present study indicated that ASC transplantation effect for skeletal muscle injury can be dramatically improved by losartan treatment inducing better niche.

Horse health has become a major concern with the expansion of horse-related industries and sports; the importance of healthy muscles for horse performance and daily activities is undisputed. Here we generated equine-induced pluripotent stem cells (E-iPSCs) by reprogramming equine adipose-derived stem cells (E-ADSCs) into iPSCs using a polycistronic lentiviral vector encoding four transcription factors (i.e., Oct4, Sox2, Klf4, and c-Myc) and then examined their pluripotent characteristics. Subsequently, established E-iPSCs were transplanted into muscle-injured Rag/ mdx mice. The histopathology results showed that E-iPSC-transplanted mice exhibited enhanced muscle regeneration compared to controls. In addition, E-iPSC-derived myofibers were observed in the injured muscles. In conclusion, we show that E-iPSCs could be successfully generated from equine ADSCs and transplanted into injured muscles and that E-iPSCs have the capacity to induce regeneration of injured muscles.

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder caused by mutations in the dystrophin gene. Adipose-derived stem cells (ASCs) are an attractive source of cells for stem cell therapy. Losartan has been reported to improve ASC transplantation in injured mouse muscles. In the present study, we investigated whether the combined treatment of losartan and ASCs in the injured muscles of mdx mice improves regeneration. The combined treatment of ASCs and losartan remarkably improved muscle regeneration and induced muscle hypertrophy. In addition, ASCs and losartan treatment downregulated transforming growth factor-β and inhibited muscle fibrosis. We observed cells coexpressing green fluorescent protein (GFP) and dystrophin in the muscle samples of mice transplanted with GFP-positive ASCs. In the coculture in vitro experiment, we also observed that the GFP ASCs differentiated into dystrophin-expressing myotubes. The present study shows that the combination of transplanted ASCs and treatment with losartan ameliorated muscle fibrosis and improved muscle regeneration in injured mdx mice. Thus, we suggest that combined treatment with losartan and ASCs could help to improve muscle regeneration in the muscles of injured patients, including DMD patients.