Decellularized Stem Cell Matrix Rejuvenates Synovium-Derived Stem Cells for Cartilage Regeneration and Repair of Partial-Thickness Cartilage Defects

Introduction Currently available treatments for partial-thickness cartilage defects do not have satisfactory clinical results. Recently, investigations demonstrated that intra-articular injection of MSCs were a feasible approach and less invasive for patients. A sufficient number of stem cells is a prerequisite for successful transplantation; however, in vitro expansion predisposes cells to lose their chondrogenic potential. Our previous studies indicated that extracellular matrix (ECM) deposited by synovium-derived stem cells (SDSCs) could provide a three-dimensional (3D) stem cell expansion system in which a large quantity of highquality stem cells could be acquired [1,2]. In this study, our goal was to (1) compare the effect of transforming growth factor beta1 (TGF-β1) and TGF-β3 on the chondrogenic induction of SDSCs pre-expanded on either ECM or Plastic; and (2) demonstrate that ECM-expanded SDSCs exhibit comparable chondrogenic ability in an animal model. Therefore, we hypothesized that TGF-β isotypes had comparable in vitro chondrogenic induction effects, an allogeneic source of SDSCs could repair partial-thickness cartilage defects, and ECM-expanded SDSCs could enhance cartilage defect regeneration. Intra-articular injection may provide a promising and minimally invasive non-surgical approach for future clinical treatment of cartilage defects. Our long-term goal is to develop an allogeneic stem cell-based minimally invasive approach for the treatment of cartilage defects to be used in the clinical setting.