Eye cell transplant restores sight in miceHope for human sight loss diseases
UK scientists have restored the sight of visually impaired mice by transplanting light-sensitive photoreceptor cells into the back of their eyes.
The study findings, which are published in the journal Nature, could lead to new treatments for people who have lost their sight as a result of degenerative eye diseases.
The loss of photoreceptor cells is the leading cause of blindness in many human eye diseases, including age-related macular degeneration, retinitis pigmentosa and diabetes-related blindness.
The eye has two types of photoreceptors – rods and cones. Rod cells are especially important for seeing in the dark as they are extremely sensitive to even low levels of light.
In the study, scientists at University College London's Institute of Opthalmology injected immature rod cells from young healthy mice directly into the retinas of adult mice that were genetically altered to be night-blind.
After four to six weeks, the transplanted cells had formed the connections needed to transmit visual information to the brain, and functioned nearly as well as normal rod-photoreceptor cells.
The researchers also tested the vision of the treated mice in a dimly lit maze.
Those mice with newly transplanted rod cells were able to use a visual cue to quickly find a hidden platform in the maze, whereas untreated mice were able to find the hidden platform only by chance after extensive exploration of the maze.
Professor Robin Ali at UCL Institute of Ophthalmology and Moorefields Eye Hospital, who led the research, said: "We've shown for the first time that transplanted photoreceptor cells can integrate successfully with the existing retinal circuitry and truly improve vision.
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.
"The findings also pave the way for techniques to repair the central nervous system as they demonstrate the brain's amazing ability to connect with newly transplanted neurons."
Dr Rob Buckle, head of regenerative medicine at the Medical Research Council (MRC), which helped to fund the study, said: "This is a landmark study that will inform future research across a wide range of fields including vision research, neuroscience and regenerative medicine.
"It provides clear evidence of functional recovery in the damaged eye through cell transplantation, providing great encouragement for the development of stem cell therapies to address the many debilitating eye conditions that affect millions worldwide."
The research was funded by the MRC, the Wellcome Trust, the Royal Society, the British Retinitis Pigmentosa Society, Alcon Research Institute and The Miller's Trust.
This article was published on Thu 19 April 2012
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