Researchers Use Gene Therapy to Restore Eyesight in Blind Mice

A new study has used gene therapy to bring back eyesight in mice that had a form of hereditary blindness.

The finding may have an impact on many of the common blinding diseases in humans, researchers now state.

The study was conducted by a team of researchers led by John J. Alexander at the University of Florida.

As part of the study, researchers conducted experiments on mice that had a hereditary blindness called achromatopsia.

This disease affects eyesight by putting cone photoreceptors in the retina out of action. The disease not only causes almost complete color blindness, but also very poor central vision.

As a part of the research the researchers used a harmless virus to provide corrective genes to mice with a genetic impairment that blocks their vision.

Researchers measured the electrical activity in the retinas of mice for two months after the administering the gene therapy injection into the subretinal space of the rodents.

Scientists found that 19 out of the 21 treated eyes responded to therapy positively, and 17 of those 19 had electrical readings from their retinas much similar to those taken in normal mice.

Tests in mice between 6 and 7 months old showed that 18 of the 21 treated eyes responded in a normal manner.

Also, a smaller group of treated mice were assessed with a test similar to doctor’s eye test. Researchers found that the mice had normal visual perception with their treated eyes.

"People can talk and tell us what they see," Nature quoted Alexander, as saying.

"Animals are much more difficult. What makes this test so fantastic is that it involves an animal’s natural response, and the results tell us that the animals’ brains are involved in the process, that they are actually seeing something," he added.

The research shows that it is possible to focus and save cone cells which are the vital for visual sharpness and color vision in people.

According to Richard Weleber, a professor of molecular and medical genetics at Oregon Health & Science University who was not involved in the research, the study this cone-targeted gene therapy is first on its kind and has great implications for a number of degenerative diseases.

"This is the first to my knowledge of a cone-targeted gene therapy that restores function in an animal model where cones are the primary defect," Weleber said.

"This validates the concept that it is possible to deliver a gene therapy targeting the cone system, and that is incredibly important for a number of degenerative diseases," he added.

The findings of the study were published in the online edition of Nature Medicine.

Source: ANI
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