Cell transplantation for spinal cord injury focusing on iPSCs

Introduction: Reports of functional recovery from spinal cord injury (SCI) after the transplantation of neural stem cells (NSCs) derived from fetus/embryonic stem cells (ESCs), has raised great expectations for the successful clinical use of stem cell transplantation therapy. However, the ethical issues involved in destroying human embryos or fertilized oocytes to obtain NSCs have been a major obstacle to developing clinically useful stem cell sources, and the transplantation of stem cells isolated from other human embryonic tissues has not yet been developed for use in clinical applications. Areas covered: Recently, induced pluripotent stem cells (iPSCs), which can serve as a source of cells for autologous transplantation, have been attracting a great deal of attention as a clinically viable alternative to stem cells obtained directly from tissues. In this review, the authors outline the neural induction of ESC/iPSC, their therapeutic efficacy in SCI and their safety in vivo. Expert opinion: Although iPSCs offer great promise as the cell source for autologous transplantation for SCI, safety issues including tumorigenicity should be determined prior to the clinical trial.