Exosomes from the synovial microenvironment in joint homeostasis and osteoarthritis

Abstract

IntroductionOrthobiologics, such as mesenchymal stem cells (MSCs), known for their multipotency, are key players in stem cell therapy. One of the ways MSCs realize their therapeutic potential, is through the release of extracellular vesicles (EVs), small lipid membrane-bound structures that carry bioactive materials from their progenitor cells. This review aims to provide an overview of EVs in and from the synovial joint in both physiological and pathological context specifically in osteoarthritis (OA). MethodsThis narrative review synthesizes findings from PubMed using key words - orthobiologics, EVs, synovial joint EVs, osteoarthritis, synovial fluid. This review focuses on the potential of EVs isolated from different sources of MSC’s found in the synovial joint, evaluating their differentiation capacity and contributions to joint health and OA. ResultsEVs from various MSC types show promising results for osteochondral regeneration. However, the differentiation potential and therapeutic efficacy vary among cell types. Understanding the dynamic nature of the biological function of these cell types that serve as sources of extracellular vesicles is essential for predicting their therapeutic actions. The synovium itself is identified as a significant source of EVs, which may offer unique applications for treating osteoarthritis and cartilage defects. ConclusionExtracellular vesicles and exosomes play a critical role in cartilage and osteochondral defect repair. They exhibit preservative and restorative benefits for tissue injuries, highlighting their potential in treating osteoarthritis and cartilage defects. Additionally, the synovium as a source of extracellular vesicles and exosomes, presents unique therapeutic applications as orthobiologic.