Profound skeletal muscle loss can lead to severe disability and cosmetic deformities. Mesenchymal stem cell (MSC)-derived exosomes have shown potential as an effective therapeutic tool for tissue regeneration. This study aimed to determine the regenerative capacity of MSC-derived exosomes for skeletal muscle regeneration. Exosomes were isolated from human adipose tissue-derived MSCs (AD-MSCs). The effects of MSC-derived exosomes on satellite cells were investigated using cell viability, relevant genes, and protein analyses. Moreover, NOD-SCID mice were used and randomly assigned to the healthy control (n = 4), muscle defect (n = 6), and muscle defect + exosome (n = 6) groups. Muscle defects were created using a biopsy punch on the quadriceps of the hind limb. Four weeks after the surgery, the quadriceps muscles were harvested, weighed, and histologically analyzed. MSC-derived exosome treatment increased the proliferation and expression of myocyte-related genes, and immunofluorescence analysis for myogenin revealed a similar trend. Histologically, MSC-derived exosome-treated mice showed relatively preserved shapes and sizes of the muscle bundles. Immunohistochemical staining revealed greater expression of myogenin and myoblast determination protein 1 in the MSC-derived exosome-treated group. These results indicate that exosomes extracted from AD-MSCs have the therapeutic potential for skeletal muscle regeneration.

Background: Dysphagia is prevalent in geriatric patients, such as elderly hip fracture patients, and is associated with a poor prognosis. This study investigated (1) the prevalence of dysphagia based on clinical screening and a video-fluoroscopic swallowing study (VFSS), (2) the risk factors of dysphagia, and (3) the prognostic implications of dysphagia in elderly patients (≥ 65 years) undergoing hip fracture surgery. Methods: In this retrospective study, data from 393 female and 153 male patients ≥65 years of age who underwent surgery for a hip fracture between 2015 and 2018 were analysed. Patients who were considered at high risk of dysphagia after screening underwent a VFSS. To identify risk factors of dysphagia, demographic factors, the American Society of Anesthesiologists classification, past medical history, known risk factors of dysphagia, and factors associated with surgery were analysed using a binary logistic regression model. Odds ratios (ORs) of dysphagia for having poor prognosis including postoperative pneumonia, intensive care unit (ICU) admission, and death within 6 months after surgery were obtained by logistic regression. The association of postoperative pneumonia with poor prognosis was also analysed. Results: Dysphagia was seen in 5.3% of hip fracture patients. In multivariate regression analysis, a serum albumin level < 3.5 g/dL was identified as a risk factor for dysphagia (OR [95%CI] = 3.13 [1.40, 7.01]). Dysphagia was identified as a risk factor for postoperative pneumonia in regression analysis after adjustment (OR [95%CI] = 3.12 [1.05, 9.27]). Postoperative pneumonia was significantly associated with ICU admission (OR [95% CI] = 4.56 [1.85, 11.28]) and death within 6 months after surgery (OR [95% CI] = 2.56 [1.03, 6.33]). Conclusions: Dysphagia in elderly hip fracture surgery patients was associated with postoperative pneumonia, a risk factor for poor outcomes including ICU admission and death within 6 months after surgery. A serum albumin level < 3.5 g/dL was identified as a risk factor for dysphagia. Therefore, diagnostic testing should be performed to detect dysphagia, especially in patients with a low serum albumin level. Finally, particular care should be taken to prevent postoperative complications in patients with dysphagia.