Blind mice see again after gene therapy
Blind mice have been given back their vision using gene therapy to turn non-light responsive cells into the equivalent of digital camera pixel sensors.
British scientists who conducted the study hope to test the same approach on clinical trial patients within about three years.
Most cases of incurable blindness occur due to the loss of millions of light-sensitive photoreceptor cells that function like camera sensors.
The research involved reprogramming surviving non-light sensitive cells in the retina to convert them into new photoreceptors.
A virus was used to carry the gene for the light-sensitive protein melanopsin into the cells’ DNA.
The technique was tested on laboratory mice blinded by the degenerative disease retinitis pigmentosa (RP), the most common cause of vision loss in young people.
Clear evidence of restored sight was seen 13 months after the virus was injected into the animals’ eyes. Their pupil reflexes showed they responded to light, and they were able to perform tasks requiring basic image recognition.
Lead author Dr Samantha de Silva, from the Nuffield Laboratory of Ophthalmology at Oxford University, said: “There are many blind patients in our clinics and the ability to give them some sight back with a relatively simple genetic procedure is very exciting. Our next step will be to start a clinical trial to assess this in patients.”
Her group is currently running two trials of other gene therapies for the inherited blindness disorders choroideremia and Xlinked retinitis pigmentosa.
Both of these took two to three years to complete the journey from lab to clinic, she said.
Dr de Silva said: “We hope that a human melanopsin gene therapy clinical trial would be achievable along the same timescale.”
The scientists added: “These results suggest that this approach may be clinically useful in vision restoration in patients with end-stage RP.”