Perinatal and Wharton's jelly-derived mesenchymal stem cells in cartilage regenerative medicine and tissue engineering strategies

Stem cells can be found in embryonic and extraembryonic tissues as well as in adult organs. In particular, research in the last few years has delineated the key features of perinatal stem cells derived from fetus-associated tissues. These cells show multiple differentiation potential, can be easily expanded ex vivo, and raise no ethical concerns as regards their use. Several reports indicate that cells isolated from Wharton's jelly (WJ), the main component of umbilical cord extracellular matrix, are multipotent stem cells that express markers shared by other mesenchymal stem cells (MSC) and give rise to different mature cell types belonging to all three germ layers. Moreover, WJ-MSC display promising hypoimmunogenic and immunomodulatory properties, since they express molecules able to modulate NK cells and expand regulatory T-cell populations. In this review, we focus on the use of perinatal stem cells for regenerative medicine aimed at cartilage repair and regeneration. Cartilage is a specialized connective tissue which has poor regeneration and self-repair capacity in vivo. Traumatic injury or autoimmune processes are among the main causes of cartilage damage and degeneration, for which new hope comes from tissue engineering using stem cells which have undergone chondrocyte-like differentiation. We analyze the in vitro and in vivo data on the use of perinatal stem cells, in particular WJ-MSC, for cartilage regenerative medicine. The high variability of cell sources, the use of different types of scaffolds and matrixes, and the administration of several combinations of growth factors clearly point out the need for further research to optimize this cellular therapy approach and translate the results obtained from bench to clinic.