Exosomes in Osteoarthritis: A Review on Their Isolation Techniques and Therapeutic Potential.

Background: Exosomes are the smallest extracellular vesicles (30-150 nm) secreted by all cell types, including synovial fluid. However, because biological fluids are complex, heterogeneous, and contain contaminants, their isolation is difficult and time-consuming. Furthermore, the pathophysiology of osteoarthritis (OA) involves exosomes carrying complex components that cause macrophages to release chemokines and proinflammatory cytokines. This narrative review aims to provide in-depth insights into exosome biology, isolation techniques, role in OA pathophysiology, and potential role in future OA therapeutics. Methods: A literature search was conducted using PubMed, Scopus, and Web of Science databases for studies involving exosomes in the osteoarthritis using keywords "Exosomes" and "Osteoarthritis". Relevant articles in the last 15 years involving both human and animal models were included. Studies involving exosomes in other inflammatory diseases were excluded. Results: Despite some progress, conventional techniques for isolating exosomes remain laborious and difficult, requiring intricate and time-consuming procedures across various body fluids and sample origins. Moreover, exosomes are involved in various physiological processes associated with OA, like cartilage calcification, degradation of osteoarthritic joints, and inflammation. Conclusion: The process of achieving standardization, integration, and high throughput of exosome isolation equipment is challenging and time-consuming. The integration of various methodologies can be employed to effectively address specific issues by leveraging their complementary benefits. Exosomes have the potential to effectively repair damaged cartilage OA, reduce inflammation, and maintain a balance between the formation and breakdown of cartilage matrix, therefore showing promise as a therapeutic option for OA.