Regenerative Medicine and Tissue Engineering

Genetic factors, age, and comorbidities contribute to tissue repair and regeneration. Successful regeneration requires the activation of homeostatic molecular signaling pathways which, in turn, recruit, activate, and regulate distinct, specialized populations of resident mesenchymal stem and progenitor cells. Cellular therapeutics, including autologous chondrocyte implantation and its variants, are currently used for the repair of cartilage defects, but their complex manufacture and the autologous nature of most cellular products represent a challenge for their routine clinical application. The use of culture-expanded mesenchymal stromal cells may circumvent some of the limitations of autologous chondrocyte implantation but, more than 20 years since their inception, their noninferiority to culture-expanded chondrocytes remains to be demonstrated. More recently, the increased understanding of molecular signals regulating native joint-resident progenitor cell function is leading to the development of pharmacologic interventions that trigger intrinsic repair mechanisms. Such interventions hold the promise of affordable, effective, minimally invasive, and reproducible cartilage repair for routine clinical use.