The researchers plan to carry out clinical trials within two years, potentially leading to a replacement for the current treatment, which relies on cornea donors.
A research paper on their work was published in the online edition of the British academic journal Nature on 10 March.
The team led by Koji Nishida, a professor of ophthalmology at Osaka University, produced a section of tissue comprising the “ingredients” of a lens and a cornea from human iPS cells. From this, they produced a 0.05-millimeter-thick sheet of the corneal epithelium cells that make up an outer layer of the cornea.
“Using this technology, we might be able to help patients who had been deemed to be untreatable,” said Nishida.
In laboratory testing, the sheet was transplanted to the diseased eye of a rabbit, and its therapeutic effect was confirmed.
The research team will apply to conduct clinical research by spring 2017 with the aim of transplanting the cornea cell onto an actual patient within two years.
Prospective patients include those whose corneal epitheliums have been damaged by the side effects of medication or burns.
This condition has been relatively hard to treat compared with the more common condition in the corneal endothelium (inner surface of the cornea), and it is estimated there are several hundred patients in Japan.
The cornea is a transparent layer that covers the surface of a pupil. If a person loses the stem cells that produce corneal cells due to disease or injury, conjunctiva often overtake the surface and can cause blindness.
Transplanting corneas from donors carries a risk of rejection, and donors are always in short supply. Transplantation of mucous membrane cells from a patient’s mouth was previously developed, but the technique could only enable limited clarity of vision.
Using patients’ own iPS cells is expected to cut down the risk of rejection.
According to the team, corneas contain no blood vein, which means it is very unlikely that the iPS cells would grow cancerous. They have come across no such case during the research to date.
There are precedent cases of clinical research using iPS cells. In one such case the government-affiliated research institute RIKEN transplanted iPS-derived retina tissue.
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