Recent advances in stem cell research are leading to realization of regenerative medicine for the retina, which was previously considered impossible. The retinal pigment epithelium (RPE) is the primary target of regenerative medicine for the retina, followed by neuronal cells in the inner retina. RPE senescence is a key contributor to age-related macular degeneration (AMD), and the replacement of impaired RPE can be a causal therapy for AMD. We successfully carried out a transplantation of a sheet of RPE differentiated from autologous induced pluripotent stem (iPS) cells in a patient with neovascular AMD. This was the first successful instance of in-human iPS cell-based therapy. The primary purpose of this pilot clinical trial, confirmation of the safety of iPS cell-based therapy, was achieved and morphological and subjective effects of the treatment were observed. Although the autologous iPS cell-based transplantation succeeded medically, it is likely that autologous iPS cell therapy is too costly and meconsuming for wide-spread clinical use. Currently, we are carrying out clinical research into HLA-matched allograft iPS cell-based transplantation, a method that considerably reduces the time and cost necessary for the procedure. In addition, we recently achieved progress in iPS cell-derived photoreceptor transplantation in an animal study.
Paroxysmal kinesigenic dyskinesia is a rare disorder, characterized by recurrent and brief attacks of involuntary movements such as choreoathetosis and dystonia, triggered by sudden movements. A 12-year-old boy presented with paroxysmal episodes,which occurred mainly on the left upper limb. His involuntary movements consisted of chorea, athetosis, and dystonia, but were not accompanied by impaired consciousness, and spontaneously disappeared within 1 minute. In the intermittent phase of the attack, we observed no physical abnormalities and altered laboratory findings. Symptoms disappeared promptly after starting carbamazepine therapy. This disease responds well to medication. Therefore, it is important to have a good understanding of this disease, to avoid misdiagnosing it as a psychogenic reaction or tic.