Researchers based in the western Japanese city of Kobe started on Thursday a pilot study that uses human induced pluripotent stem (iPS) cells to regenerate human retinas, the world's first clinical trial of iPS cells.

The pilot clinical program is being conducted by a group led by Masayo Takahashi at the Laboratory for Retinal Regeneration, RIKEN Center for Development Biology Kobe Institute in collaboration with the Institute for Biomedical Research and Innovation in Kobe. The city's general hospital will also support the team.

According to RIKEN Kobe, the team plans to transplant autologous iPS cell-derived retinal pigment epithelium (RPE) cell sheets in patients with exudative age-related macular degeneration to check the safety and feasibility of the technique, which is expected to become a new therapy to restore vision.

Takahashi's laboratory said the 6-year and 10-month protocol for the new study will start with the establishment of autologous iPSCs from each of the test subjects. These iPSCs will then be differentiated into RPE cell sheets using a technology that allows these epithelial cells to be transplanted in monolayer cell sheets. The team estimates 10 months for production and validation of the autologous iPSCs and subsequent RPE cell sheets.

RIKEN Kobe Institute spokesperson Naoki Namba said the team has carried out a series of related studies on the possible formation of tumors using animals such as rats and mice. Their ultimate goal is to verify the safety of the RPE cell sheets that may be applied to the human body.

Namba said the team will transplant the tissue into 6 patients selected as early as next summer, who will thereafter be monitored to complete the project over the following years.