Mesenchymal Stem Cells for Bone and Cartilage Regeneration: State of the Art

Mesenchymal stem cells (MSCs) have essential applications in bone and cartilage regenerative medicine. Undifferentiated MSCs show a high proliferation capacity and generate progenitor cells, in addition to their differentiation ability, giving rise to specialized cells such as osteoblasts and chondrocytes. MSCs are used when tissue healing and restoration of function is impaired, including delayed healing of fractures, nonunion of fractures, bone tumors, osteomyelitis, and articular cartilage damage or degeneration. This review addresses the current advances in MSC applications to bone and cartilage regeneration. MSCs can be harvested from various sources, such as tooth pulp, adipose tissue, umbilical cord, and bone marrow. The proliferation of MSCs can be improved using 3D cell culture techniques and bioreactor systems, and differentiation can be achieved using specific in vitro stimuli. Scaffolds influence the behavior of MSCs and may direct SCs differentiation and construct integration. Experimental and clinical results demonstrate improvement in the efficiency and healing time when MSCs treat bone, cartilage, and osteochondral defects. Tissue engineering and regenerative medicine aim to restore tissue functions compromised by injuries, pathologies, or congenital diseases. Knowledge of the mechanisms of MSC proliferation and differentiation is of fundamental importance for encouraging the use of these cells. In vitro techniques that ensure the safe use of MSCs for functional tissue restoration will provide a natural and low-risk clinical alternative to conservative treatments.