Transplanted cells restore vision in mice with night blindness: study

LONDON, April 18 (Xinhua) -- British scientists have shown for the first time that transplanting special cells into the eyes of visually impaired mice can restore their vision, said a paper published online on Wednesday by the journal Nature.

There are two types of photoreceptor cells in the eye: rods and cones. The cells transplanted in this study were progenitor rod-photoreceptor cells. Rod cells are especially important for seeing in the dark as they are extremely sensitive to low levels of light.

The scientist based at University College London injected cells from young healthy mice directly into the retinas of adult mice that lacked functional rod-photoreceptors, which means they are blind in the darkness.

After four to six weeks, the transplanted cells appeared to be functioning almost as well as normal rod-photoreceptor cells and had formed the connections needed to transmit visual information to the brain.

In testing experiments, mice with newly transplanted rod cells were able to use a visual cue to quickly find a hidden platform in a dark maze, whereas untreated mice found the platform only by chance after extensive exploration of the maze.

"We've shown for the first time that transplanted photoreceptor cells can integrate successfully with the existing retinal circuitry and truly improve vision," said Professor Robin Ali, who led the research at University College London.

"We're hopeful that we will soon be able to replicate this success with photoreceptors derived from embryonic stem cells and eventually to develop human trials," he added.

Loss of photoreceptors is the cause of blindness in many human eye diseases including age-related macular denegation, retinitis pigmentosa and diabetes-related blindness.