Blind mice got their vision back after undergoing retinal stem cell transplants, say scientists from the Institutes of Ophthalmology and Child Health (University College London) and Moorfield’s Eye Hospital, London. The researchers say there is hope this study could eventually lead to sight restoration for humans blinded by diabetes or age-related macular degeneration.

You can read about this study in the journal Nature.

In this study, the mice suffered from photoreceptor loss – a type of eye damage which is a common cause of human blindness.

Currently, treatment for people who are losing their eyesight focusses on preventing or delaying the loss of the cone and rod photoreceptors. However, currently there is no medical procedure for people who have already lost their vision. This study offers hope that one day people who have gone blind may regain the cone and rod photoreceptors in the retina – and see again.

The retina is considered to be a good candidate for cell transplant. Even when the photoreceptors are gone, connections to the brain are still there. In other words, bits might be missing, but the wiring is still there. Previous trials had failed because the cells were too immature – they did not develop into photoreceptor cells.

A stem cell is a cell which can be programmed to grow into any type of cell.

In this new study, the scientists managed to transplant stem cells which were still immature, but less so than before – this time they were set up so that they would grow into photoreceptors. The cells came from the retinas of 3-day-old mice. They were placed (transplanted) into eyes of the blind mice.

The scientists found that the blind mice gradually got their eyesight back – their pupils contracted when exposed to light.

In order to see whether this can be done with humans, the scientists aim to find a way of using adult stem cells. Another method would be to use cells from a 3-6 month old fetus – something the scientists will not pursue for ethical and legal reasons.

Adult retinas have areas with cells that might be usable, say the scientists. They added that it will be many years before any reliable medical procedure may be offered to patients.

This study was funded by the Medical Research Council.

“Retinal repair”
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“Neurobiology: Right timing for retina repair”
Nature doi:10.1038/444156a
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“Retinal repair by transplantation of photoreceptor precursors”
R. E. MacLaren, R. A. Pearson, A. MacNeil, R. H. Douglas, T. E. Salt, M. Akimoto, A. Swaroop, J. C. Sowden and R. R. Ali
Nature doi:10.1038/nature05161
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“Cell transplants help restore sight in blind mice”
The Medical Research Council (UK)
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Written by: Christian Nordqvist
Editor: Medical News Today