A new source of stem cells for repairing the cornea

Researchers at the University of Pittsburgh, USA have discovered that teeth may be a good source of stem cells to repair the eye and restore sight. The team took the cells from teeth that had been removed during routine dental treatment. The cells could one day be used to give sight back to people with corneal blindness.

The cornea is the transparent front surface of the eye. If the cornea becomes cloudy or scarred, from injury, infection or an inherited condition, it can cause sight loss if less light reaches the light-sensitive cells back of the eye.

One way to treat this type of sight loss is to transplant a cornea from a donor into the affected eye. But recently, research has focussed on how to repair the eye using stem cells. These are immature cells found all over the body that can become almost any other type of cell.

No immune rejection

In this case the researchers chose ‘adult dental pulp stem cells because they could be taken from the patient themselves (getting round any potential problems with the immune system) and because they develop in the embryo from the same source as the cornea.

The researchers treated the dental pulp stem cells in a solution to make them develop into a type of specialised cell that keeps the cornea transparent and healthy. They then tested the cells to find out whether they behaved in the same way as cells naturally grown in the eye. The next step was to grow the cells together on a support shaped like a cornea. They wanted to see whether the cells would grow into complex tissue that resembled a normal cornea, and indeed they did.

Finally the team injected the cells into the right eye of mice, keeping the left eye free of the cells for comparison. Five weeks later, the mice had clear corneas in the treated eye and showed no sign of rejecting the cells.

The results have been published in the journal Stem Cells Translational Medicine.

Fight for Sight researcher Professor Julie Daniels is also working on cell repair for damaged corneas. In a current PhD studentship her team at the UCL Institute of Ophthalmology is aiming to turn stem cells from the eye itself into working corneas.

Tissue engineering

“We’re using a tissue engineering approach,” said Daniels, Professor of Regenerative Medicine and Cellular Therapy. “This is where we can make a very simple tissue in the laboratory and we can grow stem cells inside of it and on the top of it. We’re hoping to make something that’s more tissue-like than just giving back cells on their own, to be used in the longer term future for patients with corneal scarring. Currently those patients may receive a whole corneal tissue transplant from a donor, but the numbers of suitable tissues available are decreasing with time, so we’re hoping to find alternative ways to help those patients.”