London: Scientists based at the Centre for Sight in East Grinstead have become the first UK team to use adult stem cells in treating blindness. Their success mirrors similar work conducted by Indian scientists based at the LV Prasad Eye Institute in Hyderabad.
Twenty British patients have so far benefitted from the new transplantation surgery performed by Sheraz Daya. The scientists first harvested adult stem cells from the limbal region of the eye. These cells were then cultured in the laboratory for several weeks before being implanted into the patients’ eyes.
Daya’s technique involves taking stem cells from dead donors, living relatives or even the patients themselves. The cells are grown in the laboratory for two to three weeks until they form sheets, which are laid on the surface of the eye to help it heal. All the patients had lost vision because they had few or no limbal stem cells as a result of burns, chemical accidents or disease.
These cells, made just under the surface of the eye, are constantly regenerating: they keep the outermost epithelial layer of the eye clear so that it can act as an barrier against germs and dust. Without sufficient limbal cells, the cornea becomes overgrown, and vision becomes impaired.
“Before we transplant, we scrape off the material that has grown over the eye,” says Daya, who this month presented the results of a clinical trial of his technique to an international conference of eye specialists in Washington. “We lay the cultured stem cells on top and then cover them with a biologic dressing made from amniotic membrane which contains growth factors. The patient is given eye drops made from his own blood plasma, which also helps the cells to grow.”
Daya estimates that the procedure might be suitable for up to 1,000 patients in the UK. “The results are quite dramatic and, five years on, seven of the first 10 patients still have good vision,” he says. “We have not seen survival rates like this before.”
Leading transplant surgeon Prof Nadey Hakim of St Mary’s Hospital, Paddington, has welcomed Daya’s findings. “Should we succeed in generating entire new organs using the patient’s own genetic material, this would overcome the likelihood of the patient rejecting the transplanted organ and cancel the need for immunosuppressive drugs. The work of Daya has undoubtedly brought us closer to realising this dream,” he said.