Posted on behalf of David Cyranoski

It will be the first clinical study to put induced pluripotent stem (iPS) cells into humans — and where more fitting than in Japan, where Shinya Yamanaka garnered a Nobel prize last December for showing how to take bodily cells and return them to an embryo-like pluripotent state.

Masayo Takahashi of the Center for Developmental Biology in Kobe just cleared the second and, observers say, most difficult hurdle in starting her iPS cell trial to treat age-related macular degeneration, a condition that affects the retina and can lead to blindness.

On Wednesday an institutional review board (IRB) at the Institute for Biomedical Research and Innovation (IBRI), which is going to sponsor the trial, gave conditional approval. The team needs now only to notify the IRB of the final results of some preclinical safety trials now underway (see story in Japanese).

Having already received IRB approval at her home institution, Takahashi can now move towards the final step before patient recruitment: getting health ministry approval. She’s expected to receive that in time for starting the trials during this fiscal year, ending March 2014.

The trial will enrol six patients older than 50 years of age. The researchers will remove damaged pigment epithelium and then implant a small sheet of new epithelium. The sheet will be created by coaxing iPS cells, created from the patient’s body cells, to become epithelium cells.

Takahashi says that apart from a small risk of damage from the surgical procedure itself (sticking a needle in the eye) and a much smaller risk of the stem cells themselves going awry, preclinical studies suggest the procedure to be safe.

The clinical trial, meant to demonstrate the safety of the procedure in humans, is not expected to reverse the damage of macular degeneration, but researchers hope that it will at least slow its progress.