Adapted from University College London (UCL)
A research team from University College London took cells from three-to-five day old mice as they were at a stage when photoreceptors are formed. Photoreceptors are the light sensitive nerve cells that line the back of the eye, like the pixels of a digital camera. They contain chemicals that change when they are hit by light which causes an electrical signal which is then sent to the brain along the optic nerve. The researchers then transplanted the photoreceptor precursor cells into the retina of mice that were blind due to a genetic defect which mimicked a disease in humans known as retinitis pigmentosa.
The transplants were successful; the photoreceptors implanted and made electrical connections to the animal’s existing retinal nerve cells. Tests showed that the mice’s pupils responded to light and that there was activity in the optic nerve, which demonstrated signals were being carried to the brain.
The research is still in very early stages and possibly years away from human clinical trials, but the scientists are very encouraged by the results of the study and hope that retinal diseases such as retinitis pigmentosa and macular degeneration can one day be treated using this retinal transplantation technique.
The work was carried out by scientists at UCL Institute of Ophthalmology and UCL Institute of Child Health, and reported in the November 9, 2006 issue of the journal Nature.