Japan is on the verge of a major breakthrough in medicine, thanks to years of work on induced pluripotent stem cells (iPS cells) — a type of cell that can be turned into almost any tissue in the body. These cells are being tested to treat a range of conditions, from blindness and spinal injuries to Parkinson’s disease, and some treatments may be approved soon.
The field was launched by Shinya Yamanaka, who discovered in 2006 that adult cells could be “reprogrammed” into iPS cells. This earned him a Nobel Prize in 2012 and kicked off a wave of stem-cell research across Japan. Since then, the Japanese government and private funders have invested over ¥110 billion ($760 million) into regenerative medicine.
One of the pioneers, Masayo Takahashi, used iPS cells in 2014 to treat a woman with macular degeneration, a condition that causes vision loss. The patient’s vision was stabilized for 10 years. Now, Takahashi’s team is working on more scalable, donor-based treatments using robotic systems to produce large batches of cells for eye therapies.
There are now more than 60 iPS cell trials worldwide, with about a third of them in Japan. Thanks to Japan’s fast-track approval system, some of these therapies could be available as early as this year — Parkinson’s disease being a likely candidate.
Other researchers are pushing the boundaries too:
- Jun Takahashi (Masayo’s husband) has led trials using iPS cells to treat Parkinson’s, with patients showing significant improvement in movement.
- Hideyuki Okano has treated patients with spinal cord injuries, and one now stands independently.
- Kohji Nishida has restored corneal vision using iPS cell transplants, with strong results in early trials.
While these results are promising, there are still challenges. Producing personalized (autologous) treatments is expensive, and donor-derived therapies come with risks like immune rejection or genetic mutations. In one case, a trial was halted when a mutation was found in the cells right before transplant — even though no harm occurred.
Japan’s regulatory system allows early use of treatments that show potential and are deemed safe, but this approach has raised some concerns. Some previously approved therapies were later pulled due to lack of benefit. Still, many experts believe that for rare or hard-to-treat conditions, this risk is acceptable.
Looking ahead, facilities like Sumitomo Pharma’s manufacturing plant and Takahashi’s robotic lab in Kobe are preparing to deliver treatments at scale. A project called myiPS in Osaka is aiming to make personalized iPS cells for about ¥1 million per patient, a big step toward affordability.
Finally, medical tourism could become a reality. One clinic near Tokyo’s Haneda Airport is preparing to offer these treatments — possibly to wealthy Japanese patients and international visitors, since the costs (estimated at ¥10 million or more) are not yet covered by Japan’s public health system.
Despite the hurdles, momentum is building. As more patients see results, researchers hope stem-cell therapies will soon move from cutting-edge to commonplace.
