Altered stem cells help repair cornea

In a world-first, Japanese scientists have successfully repaired a damaged cornea to improve a person’s vision, using ‘induced pluripotent cells’.

Pluripotent stem cells are embryonic cells that have the capacity to self-replicate by dividing and developing into almost any cell of the adult body. Scientists create induced pluripotent stem (iPS) cells by reprogramming adult cells, usually from skin or blood cells, into an embryonic-like pluripotent state. This enables the iPSC to develop into any type of human cell that are needed for therapeutic purposes.

Cornea is the thin clear section that covers the front of the eye, including the iris and pupil. Stem cells in the cornea are usually refreshed and repaired when necessary, thereby keeping it clear so that light can enter.

However, if these corneal stem cells sustain damage due to disease or injury, maintenance of the cornea is no longer possible, and this can lead to corneal blindness. Individuals with damaged corneas must wait for donor tissue to become available, and — as with any organ transplant — this can be a lengthy process.

Now, ophthalmologists at Osaka University in Japan, treating a patient with blurry vision caused by a genetic condition that affected her corneal stem cells, have successfully implanted thin sheets of iPS cells into the patient’s eye. These iPSC then took root in her eye and took over the role played by inactive corneal stem cells and gradually restored her vision.

Although stem cells had caused excitement in medical circle they have been at the center of ethical concerns over the use of fetal tissue to generate them. There is no such controversy surrounding iPS cells, as they are derived from the patient’s own body, and they also have the advantage of not causing any transplant rejection.

In Japan, researchers have already tested iPS cells against a number of conditions in clinical trials, including spinal cord injuries and Parkinson’s disease. In October 2018, a neurosurgeon implanted 2.4 million cells into the brain of a patient with Parkinson’s disease.

A recent global survey of corneal transplantation concluded that there is “only one cornea available for 70 needed.” Hopefully, this groundbreaking technology will, eventually, go a long way toward closing that gap.