Abstract
Osteoarthritis and rheumatoid arthritis are osteoarticular diseases affecting primarily cartilage and bone. They are a high public health problem because of their prevalence and absence of curative treatment. Innovating cell therapy approaches are being evaluated in the clinic for treating these diseases. They rely on the use of mesenchymal stem cells (MSCs), which display immunosuppressive and regenerative functions and could provide new hope for patients. These cells release extracellular vesicles, which are very powerful tools for intercellular communication and are classified into 3 populations: exosomes, microparticles (MPs) and apoptotic bodies. In the present study, we characterize and compare the in vitro and in vivo effects of MSC-derived exosomes and MPs. We show for the first time that exosomes and MPs exert in vitro anti-inflammatory, anti-apoptotic and chondroprotective functions. In vivo, only exosomes exert a therapeutic effect in an experimental model of inflammatory arthritis. However in a model of osteoarthritis, both exosomes and MPs protect cartilage and bone from degradation, in a similar fashion. This study provides the proof-of-concept that MSC-derived exosomes and/or MPs exert a therapeutic effect in rheumatic diseases.