ADSC-derived mitochondrial nanovesicles transplantation alleviates capsular fibrosis and inflammation and improves joint mobility in a rat model of adhesive capsulitis.

BACKGROUND: Adhesive capsulitis (frozen shoulder) is a prevalent condition characterized by shoulder pain and progressive motion loss. Mitochondrial metabolic dysregulation is an underlying driver of chronic inflammation and fibrosis. This study aimed to characterize mitochondrial metabolic abnormalities in patient capsular tissue and evaluate a therapy using adipose-derived stem cell (ADSC) derived mitochondrial nanovesicles transplantation. METHODS: Single-cell RNA sequencing was utilized to analyze the expression of nuclear-encoded genes related to mitochondrial metabolism in fibroblast subpopulations from human adhesive capsulitis capsular tissue. ADSC-derived membranes were extruded together with exogenous mitochondria to generate engineered mitochondrial nanovesicles (AD-Mito-NPs). An inflammatory fibroblast model was employed to assess the uptake of AD-Mito-NPs, along with associated transcriptomic and metabolomic changes, and their effects on apoptosis, inflammation, and extracellular matrix (ECM) remodeling. Finally, AD-Mito-NPs were locally injected into a rat model to evaluate joint movement and histopathology. RESULTS: AD-Mito-NPs retained intact respiratory function, high fibroblast internalization efficiency, and stable physicochemical properties for up to 7 days. In vitro inflammatory models verified that AD-Mito-NPs reversed IL-1β-triggered mitochondrial injury and strengthened mitochondrial oxidative phosphorylation. Furthermore, AD-Mito-NPs alleviated intracellular reactive oxygen species accumulation and fibroblast apoptosis, mitigated inflammatory responses, and remodeled extracellular matrix homeostasis. In vivo, intra-articular administration of AD-Mito-NPs improved shoulder joint mobility, attenuated capsular thickening and disordered collagen arrangement, and suppressed local inflammation in a rat model of adhesive capsulitis. CONCLUSION: Mitochondrial metabolic imbalance is a factor driving capsular fibrosis in adhesive capsulitis. Engineered mitochondrial transplantation offers therapeutic benefits by enhancing mitochondrial energy production, mitigating oxidative stress and inflammation, and restoring ECM balance. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This article identifies mitochondrial metabolic dysregulation as a key driver of adhesive capsulitis-related capsular fibrosis and demonstrates that engineered AD-Mito-NPs are a safe platform for clinical translation. These NPs effectively enhance energy metabolism, reduce inflammation, and improve shoulder mobility in models, providing a promising alternative to existing treatments.