Stem Cells and Regenerative Medicine

ESCs constitute the entire organ systems of our body through proliferation and differentiation starting from a single fertilized egg at the beginning of the embryonic stage. Adult stem cells maintain the structural and functional integrity of the organ systems throughout the lifespan through mobilization from the niche, self-renewal for propagation, homing to the destination, and target tissue lineage differentiation when an injury occurs in an organ system. It could be speculated that ESCs determine the quality of our organ systems at birth and adult stem cells maintain our health status after birth. Therefore the quality and quantity of endogenous adult stem cells would determine our healthy lifespan. For this reason, the focus in the future of stem cell research and technology development would be shifted to the promotion of healthy longevity although our efforts currently focus more on the treatment by stem cells of chronic diseases. In this context, the most challenging technology of regenerative medicine will be how to ensure the availability, either endogenously or exogenously, of stem cells to the needed organ systems.