Blindness cure could come from stem cells

Published on Thursday 9 April 2009 21:34

A STEM-CELL therapy that restores transparency to cloudy corneas could provide a future cure for blindness, it was claimed yesterday.

Scientists who successfully tested the treatment in mice believe it has enormous potential for humans, especially in developing countries.

The cornea is the outer layer that shields the eye and also works with the lens to focus light on to the retina. Infections, injuries, inherited diseases and poor nutrition can lead to scarring of the cornea, causing it to cloud over.

In poorer parts of the world, damage to the cornea is a major cause of impaired and lost vision. River blindness, an African disease spread by a parasitic worm, leads to corneal damage and affects 17 million people.

The US scientists took stem cells from human corneas and implanted them into the eyes of partially blind mice. The animals had opaque patches on their corneas, due to the lack of a structural protein.

Three months after treatment with the stem cells, the cloudiness was gone and their corneas were as transparent as those of normal mice.

Stem cells are immature cells that can develop along a number of different pathways.

Previously, the same team identified a population of stem cells in a layer of the cornea called the stroma. Tests showed that, even after multiplying many times over in the laboratory, the cells retained their ability to produce structural components of the cornea.

The study leader, Dr James Funderburgh, of the University of Pittsburgh School of Medicine, said: "Our experiments indicate that, after stem-cell treatment, mouse eyes that initially had corneal defects looked no different than mouse eyes that had never been damaged."

The research was reported in the journal Stem Cells.