We aim to develop iPS cell-based therapies for intractable neurological diseases, including using transplanted cells to improve physical functions by repairing neuronal connections. Our main focus is Parkinson's disease, where transplants of fetal midbrain substantia nigra cells have allowed us to gain clinical experience, test efficacy, and identify problems.

Achieving successful cell-based therapy requires attention to various issues, and we have been addressing them gradually: 1) the induction of dopaminergic neurons without using animal factors, 2) cell sorting to inhibit tumor formation, 3) transplanted cell survival and post-transplant immunosuppression, and 4) the establishment of a system to confirm long-term efficacy and safety. We have used not only rodents but also non-human primates as Parkinson's disease models for behavioral and imaging analyses to confirm the safety and efficacy of transplanted cells. We have also performed detailed safety and efficacy testing with clinical-grade dopaminergic neurons. Based on these findings, we received approval from the Japanese regulatory authorities and have been conducting a physician-initiated trial in Parkinson's disease at Kyoto University Hospital since 2018 (see Figure).