Abstract
Inflammation has been associated with early degradative changes in articular cartilage and immune responses are key factor influencing normal tissue regeneration and repair. With synovitis a prominent feature in osteoarthritis (OA) and associated with the progressive degradation of articular cartilage, immune factors need to be factored into efforts to achieve efficient cartilage repair/regeneration. Recent efforts have focused on the use of autologous or allogeneic mesenchymal stem/stromal cells (MSCs) to modulate the inflammatory environment in the injured or osteoarthritic joint. Intraarticular injection of MSCS has modulated cartilage degradation in a variety of pre-clinical OA models. Results from early clinical trials have also shown effects on pain and function-associated outcome measures. Other cell types may also have some capacity for use as a therapy for OA. For example, primary allogeneic chondrocytes also seem to have some immune-privilege in the synovial joint and are immunomodulatory in a rat model. Although MSCs isolated from bone marrow that are induced to undergo chondrogenic differentiation do not retain these properties, MSCs isolated from the synovium or chondroprogenitors generated from cartilage itself may represent the future of cell therapy for OA.
