Photo/IllutrationMasayo Takahashi of the Riken research institute speaks at a news conference March 28. Beside her is Yasuo Kurimoto of the Kobe City Medical Center General Hospital.(Mari Endo)

  • Photo/Illustraion

The world's first surgery to transplant retina cells made from a donor's induced pluripotent stem cell to a patient was carried out March 28 in Kobe.

If it transpires that third-party iPS cells can be safely used for such procedures, it would open the medical door to patients receiving transplants that are quicker and cheaper than using stem cells created from the patient.

The surgeons were mainly trying to ascertain the safety of the operation. Researchers will now watch for the possible rejection of the transplanted retina as well as abnormalities arising in the transplanted cells.

The operation was a joint project involving the Riken research institute, the Kobe City Medical Center General Hospital and Kyoto University's Center for iPS Cell Research and Application (CiRA).

The outcome of the procedure will have consequences for other universities proceeding with their own clinical research using third-party iPS cells to create tissue to combat stubborn diseases.

The patient was a male in his 60s diagnosed with age-related macular degeneration, which can result in a loss of vision.

Cells from the iPS cell stock stored at CiRA were converted into retina cells and transplanted into the patient's eye. Yasuo Kurimoto, head of the ophthalmology division at the Kobe City Medical Center General Hospital, was in charge of the operation, which took about an hour and was completed without problems.

The donors of the cells created for the iPS cell stock have a special type of immune cell that does not trigger transplant rejection in most Japanese individuals. Only patients who are found to have a match with the special immune cell will be eligible to take part in the research project, which is led by Riken's Masayo Takahashi.

Scientists involved in the project said a major improvement in the patient's vision was not expected. At least four other individuals will have the surgery and the patients will be monitored for about a year to check on the safety of the transplanted cells.

Takahashi acknowledged that her team still had a huge hurdle to overcome before the procedure could become widely available.

"We are at about the halfway mark, but there is still a precipitous path ahead of us," Takahashi said at a news conference following the operation.

Clinical applications of iPS cells have virtually ceased since the world's first transplant using iPS cells created from the patient being treated was conducted in 2014.

Interest in whether iPS cells can be used for medical purposes is high not only in Japan, but overseas as well.

The Nobel laureate Shinya Yamanaka, who heads CiRA, said, "While several clinical trials have begun in the United States using embryonic stem cells, the United States and other nations are carefully watching what Japan does involving the use of iPS cells."

(This article was compiled from reports by Roku Goda and Tomoyo Fukumiya.)