Stem Cells for Articular Cartilage Repair and Regeneration

Abstract

Articular cartilage is a unique avascular load-bearing tissue comprising of dense extracellular matrix sparsely populated by chondrocytes. Due to the lack of vascularisation and low cell density, articular cartilage has a limited self-regenerative capacity. Many treatment modalities have been generated but with limited success due to formation of inferior fibrocartilage at the damaged area/injured site during the repair process. Recent advancements in stem cell biology and tissue engineering have provided notable strategies for stem cell-based therapies and cartilage tissue engineering. Several stem cell sources including adult and embryonic stem cells have been reported for their differentiation capabilities to form the cartilage. Among these various stem cell sources, mesenchymal stem cells (MSCs) represent the most promising stem cell source for cartilage regeneration, due to its availability, ease of isolation and high potency to differentiate into chondrocytes. Stem cells may be delivered directly by means of injection or seeded in scaffolds for implantation. To further enhance cartilage regeneration, advances in tissue engineering have enabled the use of scaffolds, coupled with biochemical and biophysical factors to influence stem cell chondrogenesis in their lineage-specific differentiation and phenotypic stability of the cartilage formation. Moving forward, a number of clinical trials using bone marrow-derived MSCs for articular cartilage repair have been carried out and showed successful cartilage regeneration, with features of hyaline cartilage, similar to those of the native cartilage. The translational use of stem cells, in particular MSCs, for articular cartilage repair is likely to advance rapidly in the ensuing decade.