A woman in Japan has become the first person in the world to have their cornea repaired using ‘reprogrammed’ iPS stem cells.
A team of researchers led by Kohji Nishida held a press conference on 29 August to announce the success of the first ever transplant of cornea made from induced pluripotent stem (iPS) cells. Nishida reported that the patient’s cornea remained clear and her vision has improved since the transplant over a month ago on 25 July.
The patient suffers from corneal blindness – one of the leading causes of blindness in the world. Normally, the cornea is a transparent outer layer of the eye, and stem cells are there to repair it when damaged. However, the loss/destruction of these stem cells due to trauma or illness leads to corneal scarring, and vision becomes blurred or even lost entirely. Currently, the only available treatment is corneal transplants from donors who have died, however there are often chronic shortages of cornea donors and complications due to rejection of the transplanted tissue.
What is so revolutionary about this new iPS cornea transplant? iPS stands for induced pluripotent stem cells, which are created by ‘reprogramming’ cells from body tissues (commonly skin and blood cells) to revert to an embryonic-like state where they can then transform into other tissue, such as corneal cells. The advantage of this procedure is that corneal cell sheet can be produced with stable quality and is less likely to cause rejection than conventional corneal transplants.
Nishida’s team created thin (0.05mm) circular sheets of corneal epithelial cells, derived from iPS cells supplied by the Kyoto University’s Centre for iPS Cell Research and Applications. Some of the cells within the sheet are stem/progenitor cells that retain the ability to proliferate, and therefore have the potential to recover healthy corneal barrier function to the host eye after the transplant operation.
Nishida’s team were granted permission by the Japanese health ministry in March to try the procedure on 4 patients, following the success of this procedure in an animal model of corneal blindness.
Nishida noted that “If the safety and effectiveness of the iPS cell-derived transplant is substantiated, prospects of applying our method to patients to whom cornea transplantation is considered unsuitable will be increased, while at the same time eliminating the problem of a dearth of [corneal] donors.
The next operation is planned for later this year. It is hoped that this procedure can be put into practical use in 5 to 6 years for the treatment of diseased or damaged corneas.