Histological characteristics of exercise-induced skeletal muscle remodelling.

This study aims to analyse the pathological features of skeletal muscle injury repair by using rats to model responses to different exercise intensities. Eighty-four rats were randomly divided into five groups for treadmill exercise. The short-term control, low-intensity, medium-intensity and high-intensity groups underwent gastrocnemius muscle sampling after 6, 8 and 12 weeks of exercise. The long-term high-intensity group underwent optical coherence tomography angiography and sampling after 18 weeks of exercise. RNA sequencing was performed on the muscle samples, followed by the corresponding histological staining. Differentially expressed genes were generally elevated at 6 weeks in the early exercise stage, followed by a decreasing trend. Meanwhile, the study demonstrated a negative correlation between time and the gene modules involved in vascular regulation. The modules associated with muscle remodelling were positively correlated with exercise intensity. Although the expression of many genes associated with common angiogenesis was downregulated at 8, 12 and 18 weeks, we found that muscle tissue microvessels were still increased, which may be closely associated with elevated sFRP2 and YAP1. During muscle injury-remodelling, angiogenesis is characterized by significant exercise time and exercise intensity dependence. We find significant differences in the spatial distribution of angiogenesis during muscle injury-remodelling, which be helpful for the future achievement of spatially targeted treatments for exercise-induced muscle injuries.

NAMPT encapsulated by extracellular vesicles from young adipose-derived mesenchymal stem cells treated tendinopathy in a "One-Stone-Two-Birds" manner.

BACKGROUND: Tendinopathy is the leading sports-related injury and will cause severe weakness and tenderness. Effective therapy for tendinopathy remains limited, and extracellular vesicles (EVs) derived from adipose tissue-derived mesenchymal stem cells (ADMSCs) have demonstrated great potential in tendinopathy treatment; however, the influence of aging status on EV treatment has not been previously described. RESULTS: In this study, it was found that ADMSCs derived from old mice (ADMSCold) demonstrated remarkable cellular senescence and impaired NAD+ metabolism compared with ADMSCs derived from young mice (ADMSCyoung). Lower NAMPT contents were detected in both ADMSCold and its secreted EVs (ADMSCold-EVs). Advanced animal experiments demonstrated that ADMSCyoung-EVs, but not ADMSCold-EVs, alleviated the pathological structural, functional and biomechanical properties in tendinopathy mice. Mechanistic analyses demonstrated that ADMSCyoung-EVs improved cell viability and relieved cellular senescence of tenocytes through the NAMPT/SIRT1/PPARγ/PGC-1α pathway. ADMSCyoung-EVs, but not ADMSCold-EVs, promoted phagocytosis and M2 polarization in macrophages through the NAMPT/SIRT1/Nf-κb p65/NLRP3 pathway. The macrophage/tenocyte crosstalk in tendinopathy was influenced by ADMSCyoung-EV treatment and thus it demonstrated "One-Stone-Two-Birds" effects in tendinopathy treatment. CONCLUSIONS: This study demonstrates an effective novel therapy for tendinopathy and uncovers the influence of donor age on curative effects by clarifying the detailed biological mechanism.

Risk factors analysis and nomogram construction for postoperative pulmonary infection in elderly patients with hip fractures.

PURPOSE: The purpose of this study was to predict the probability of postoperative pulmonary infection in elderly patients with hip fractures by developing and validating a precise model. METHODS: The clinical data of 1008 elderly hip fracture patients undergoing surgical treatment in Shanghai Tenth Peoples' Hospital were retrospectively selected. A univariate analysis and multivariate regression were used to analyze the independent risk factors for postoperative pulmonary infection in elderly patients with hip fractures. A risk prediction model was established, and a nomogram was drawn. The area under the ROC curve and Hosmer‒Lemeshow test were used to evaluate the predictive effect of the model. RESULTS: The multivariate regression analysis indicated that age > 73, time from fracture to surgery (d) > 4 days, smoking, ASA ≥ III level, COPD, hypoproteinemia, red cell distribution width > 14.8%, mechanical ventilation time > 180 min, and stay in the ICU were independent risk factors for postoperative pulmonary infection in elderly patients. The AUCs of the model were 0.891 and 0.881, 0.843, respectively, in the two verification groups. For the Hosmer‒Lemeshow test, the P values were 0.726 in the modeling group and 0.497 and 0.231 in the verification group (P > 0.05). CONCLUSION: Overall, this study uncovered different independent risk factors for postoperative pulmonary infection in patients with hip fractures. The nomogram can effectively predict the occurrence of postoperative pulmonary infection.

Course-based intra-articular injection of medical chitosan mitigates excessive deposition of triacylglycerides in the synovial tissue of the knee osteoarthritis.

BACKGROUND: This study aimed to investigate the clinical efficacy of intra-articular injections of medical chitosan for treating knee osteoarthritis (KOA) and measure the lipid metabolism profiles of the synovial tissue. METHODS: Sixty patients with KOA undergoing conservative treatment were recruited and randomized into two groups: one without pharmacological intervention (OA group) and the other receiving course-based intra-articular medical chitosan injections (CSI group). Quantitative lipidomic profile of synovial tissue was analyzed. Functional scores, including Kellgren-Lawrence rating (K-L), Visual Analog Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scoring, and American Knee Society (AKS) scoring were conducted. RESULTS: Survival from the initial conservative treatment to final knee arthroplasty was significantly longer in the CSI group compared to the OA group. Except for the presurgery VAS score, no statistically significant differences were observed in the other scores, including K-L, initial VAS, WOMAC, and AKS. However, the CSI group experienced more reductions in AKS-Knee subscores compared to the OA group. Compared to the CSI group, the OA group exhibited a significant upregulation in most differential lipids, particularly triacylglycerides (TAGs, 77%). The OA group had notably higher levels of long-chain unsaturated fatty acids. CONCLUSION: Intra-articular injection of medical chitosan significantly prolongs the survival period before knee arthroplasty and reduces the deposition of TAGs metabolites.