Emerging Role of Exosomes in the Joint Diseases.

Exosomes are a subset of small, membrane-bound extracellular vesicles that are important for communication among cells. They originate from the cell membrane during endocytic internalization, and are stable in biological fluids, including blood and synovial fluids. Increasing knowledge is emerging about exosomes in joint diseases, including osteoarthritis, rheumatoid arthritis, osteonecrosis of the femoral head, and others. Exosomes in synovial fluid can lead to inflammation, degeneration of cartilage, and destruction of joints. Exosomes in blood have diagnostic value in the early disease stage or for complicated conditions of joint diseases. Exosomes from stem cells could delay diseases and repair joints. For a comprehensive understanding about the emerging role of exosomes in joint diseases, we introduced the isolation and verification of exosomes from synovial fluid, reviewed the physiological and pathological effects of exosomes on joints, and discussed the diagnostic value and therapeutic potential of exosomes in joint diseases. In the future, immunologically active exosomes and engineered exosomes will of interest in the joint diseases. Challenges in the field of exosomes in joint-disease research include complex and expensive isolation, detection of contributing molecular, effectiveness and safety evaluation. In summary, challenges remain, but the field of exosomes in joint diseases has potential, including in mechanisms, diagnoses and therapies.