Surgery with stem cells repairs eyes in clinical trial

Stem cells taken from dead donors have been used to restore the damaged surface of the eye in a clinical trial, which researchers say is the first of its kind.

The study saw improvements with stem cell surgery in patients with limbal stem cell deficiency (LSCD), a disorder that can result in blindness.

'The findings from this small study are very promising and show the potential for safe stem cell eye surgery as well as improvements in eye repair,' said Professor Baljean Dhillon at the University of Edinburgh, who led the study.

'Our next steps are to better understand how stem cells could promote tissue repair for diseases that are extremely hard to treat and if, and how, they could help to restore vision.'

LSCD is a disorder where the stem cells which replenish the outermost layer of the cornea – the transparent covering at the front of the eye – are damaged or missing from the limbus, an area at the border of the cornea and the white sclera. Without the ability to repair this protective layer, redness, pain, scarring and vision loss may result.

Corneal transplantation is not an effective treatment for LSCD, but there have been studies where tissue transplants from healthy limbus tissue have replenished the cornea's protective layer. This tissue ideally comes from a healthy part of the patient's own eyes, to avoid the immune system rejecting it, but this is not an option for patients with LSCD affecting the entirety of both eyes.

In this study, tissue was taken from the limbus of recently deceased donors and cultivated on a membrane commonly used in eye surgery. Sixteen LSCD patients were then randomised to receive transplants of either the cultivated stem cells, or a control graft into the eye. All patients also received eye drops containing growth promoting chemicals taken from their own blood.

After 18 months, the patients receiving the stem cell transplants showed more improvement than the control patients on the 'ocular surface score', a measurement of how damaged the corneal surface is. This includes factors such as the transparency of the cornea, and the growth of unwanted blood vessels in the corneal tissue.

However, while some treated patients also showed improvement in visual function, this was also the case for the control patients, and could have been a result of the eye drops used.

The study was published in Stem Cells Translational Medicine.