Abstract
Mesenchymal stromal cells (MSCs) have been utilized in cell therapy for various diseases. Recent studies have demonstrated that extracellular vesicles (EVs) released by MSCs play an important role in their therapeutic activities. EVs contain a variety of bioactive molecules such as proteins, messenger RNAs (mRNAs), and micro RNAs (miRNAs) and modify the function of the recipient cells by transferring these molecules. Despite the promising potential of EV therapy as a substitute for MSC therapy, there are challenges that need to be addressed for the clinical success of EV therapy. EV quality has been shown to vary from batch to batch and preparation to preparation. As the consistency and reproducibility of therapeutic effects rely on the quality of EVs, it is necessary to establish techniques to manufacture scalable amounts of EVs with the same quality. In this manuscript, we discuss the potential factors that affect EV quality. We then introduce pre-clinical studies of EV therapy for bone/cartilage diseases such as osteoarthritis, rheumatoid arthritis, and osteoporosis.