Tissue Engineering and Regenerative Medicine

Human pluripotent stem cells including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have been expected to provide an excellent tool for regenerative medicine. However, there are two major concerns in their clinical application: Immunological rejection and risk of tumorigenicity in the case of ESCs and iPSCs, respectively. Hence, their clinical application has been considered only in those cases where there are no alternative measures for effective treatments. Here, we propose that human ESCs/iPSCs can contribute to therapeutic development for the treatment of common diseases. As we recently reported, transient existence of human iPSC-derived vascular endothelical cells can exert a sustainable therapeutic effect on an injured artery preventing stenosis induction even after they are immunologically rejected. In this case, immunologically rejection creates beneficial outcomes by nullifying the risk of tumorigenesis without decreasing therapeutic effects. Another utility of human pluripotentstem cells is to provide a feasible tool for drug discovery that are otherwise unavailable. For example, sufficient amounts of brown adipocytes, which has been attracting a great deal of attention as a new target of drug discovery for the treatment of metabolic disorders, are unobtainable from living individuals due to technical as well as ethical problems. However, brown adipocytes can easily be produced from human ESCs/iPSCs as we previously reported. Potential contribution of human pluripotent stem cells to therapeutic development for the treatment of common diseases will be further discussed.