With the help of experimental gene therapy, a group of scientists from France managed to partially restore vision in a blind man with a rare degenerative eye disease. They believe that their discovery will help in the treatment of other people with severe visual impairments.
Kyiv. Ukraine. Ukraine Gate – May 25, 2021 – International News
A 58-year-old man who underwent experimental therapy was diagnosed with retinitis pigmentosa 40 years ago. This hereditary degenerative eye disease leads to the destruction of light-sensitive receptors and, consequently, to partial or complete blindness. It is estimated that retinitis pigmentosa affects about two million people worldwide.
For such people, one of the promising methods of at least partial restoration of vision is optogenetics – a technique that involves the use of light to control nerve cells. The practical application of optogenetics is currently impossible, but in the last few years, more and more discoveries have been made in this area.
As for the mentioned 58-year-old man (his name is not disclosed for ethical reasons), his eyes could still distinguish light from the darkness. And due to previous genetic therapy – optogenetic vision restoration – with the help of special glasses, he could partially see with one eye.
Today, a team of scientists from the Institute of Vision in Paris, led by Jose-Alain Sahel, has for the first time used optogenetic vision restoration to partially treat neurodegenerative eye disease. The light-sensitive protein canalrodopsin, first discovered in green algae, helped.
The therapy consisted of two stages. The first man was injected with the worst eye, a viral vector that stimulated the production of canal rhodopsins in the part of the cornea that was not affected by retinitis pigmentosa. Light-sensitive proteins now sent electrical signals to the brain – the affected eye began to distinguish light, but only its yellow hues.
That’s why scientists used special glasses with a video camera on the front and a projector on the back. This design converted external light signals into a spectrum that a man would be able to distinguish. But even so, months have passed for the production of a sufficient amount of light-sensitive protein – and the adaptation of the brain to the perception of light.
As a result, the man learned to perceive and identify the various objects that were in front of them. A notebook and a stapler box were used in the experiment. Electroencephalogram confirmed the activity of areas of the brain that are responsible for vision in humans, including the visual cortex.
“Over time, the patient has shown that he has significantly improved his daily visual tasks, such as determining where a plate, cup or phone is, finding furniture in a room or identifying a door in the hallway – but only with glasses,” the authors note.
They argue that their results may be used in the future to treat patients with near-complete or complete vision loss. However, as James Bainbridge of University College London warns, this is a high-quality study of only one patient.
Even the level of vision that has been achieved is “incredibly important for the daily life of a blind person,” they say. Now a man can detect large obstacles in the way through his eyes, and not with the help of a blind cane.
Geneticists have clarified that this patient is not the only one who has been injected with a genetic tool. Due to the COVID-19 pandemic, volunteers could not come to the centers and train properly: “We don’t know how well it will work with others, but the concept test is really impressive.”
Today there are other methods of treating retinitis pigmentosa. One involves using a camera with electrodes connected to nerve endings in the eye, and the other involves “correcting” mutated genes responsible for causing the disease (but since there may be more than 70, this method is not as reliable).
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Source: Ukrgate