More and more evidence indicates that microvesicles (MVs) play a key role in cell-to-cell communication. The MVs are circular fragments of membrane released from the endosomal compartment as exosomes or shed from the cell surface membranes of most types. Components of donor cells are incorporated into MVs that contain bioactive lipids, proteins, genetic cargoes. MVs derived from stem cells may reprogram cells that survived in injury tissue and favor tissue regeneration by delivering their bioactive cargoes to influence the behaviors of recipient cells. Compared with mesenchymal stem cells (MSCs), MVs derived from MSCs were found to mimic the beneficial effects of these cells. These proregenerative effects mediated by MVs can be explained by the fact that MVs are enriched in bioactive lipids, anti-apoptotic and pro-stimulatory growth factors or cytokines, and deliver mRNAs, regulatory miRNAs and proteins that improve overall cell function. Therefore, it opens novel perspectives in exploiting these MVs in tissue regeneration and repair. In addition, the use of MVs instead of stem cells could represent a safe and potentially more advantageous alternative to cell-therapy approaches.
ObjectiveTo review the advances in utilizing paracrine effect of stem cells in knee osteoarthritis (OA) treatment.MethodsThe researches in applying stem cells derived conditioned medium, extracellular matrix, exosomes, and microvesicles in knee OA treatment and cartilage repair were reviewed and analyzed.ResultsThe satisfying outcomes of using different products of stem cells paracrine effect in knee OA condition as well as cartilage defect is revealed in studies in vitro and in vivo. The mechanism including suppressing the intraarticular inflammation, the apoptosis of chondrocytes, and the degradation of cartilage matrix, while enhancing the synthesis of cartilage matrix, the differentiation of in-situ stem cells into chondrocytes and the migration to the affected area. The effectiveness can be further improved supplemented with the tissue engineering methods or gene modification.ConclusionCompared with the traditional stem cell therapy, applying the products from paracrine effect of stem cells in knee OA treatment is more economical and safer, presenting great potential in clinical practice.