Adult Stem Cells and Hydrogels for Cartilage Regeneration

Cartilage tissue engineering is emerging as a therapeutic approach for the repair and regeneration of cartilage tissue defects resulting from trauma and disease. It is still essential to explore approaches that employ combinations of ideal seed cells, biomaterials, and growth factors to repair defect areas because cartilage lacks spontaneous regenerative capabilities and traditional treatments do not fully satisfy clinical requirements. The purpose of this review is to summarize key advances in this area with an emphasis on adult stem cells because these cells possess a self-renewal ability and the potential for multi-directional differentiation when cultured under appropriate conditions, such as chondrocyte differentiation to synthesize cartilage-specific matrix proteins. Additionally, hydrogels and their synergistic action with growth factors to co-regulate cell behaviors and cartilage regeneration will be addressed. Hydrogels are three-dimensional water-swollen networks that provide a unique microenvironment to promote the chondrogenic phenotype by encapsulating cells as a functional cartilage substitute in a defect area. Ultimately, this review presents the prospect of combining adult stem cells, hydrogels, and growth factors using interdisciplinary approaches that may lead to significant breakthroughs in cartilage regeneration in the future.