After 40 years of blindness from a neurodegenerative disease, a man has partially regained his sight thanks to visual therapy. The treatment consists of Injection of an adenovirus into the eye Which carries a light-sensitive protein from moss and special glasses. This is the first case of partial healing of vision in a blind patient after visual genetics therapy, a technique developed at the beginning of the century that It is based on processing microbial proteins that are sensitive to light And cells across the light.
The study, published in Nature Medicine, was signed by scientists from the Sorbonne (France), the University of Pittsburgh (USA) and the University of Basel (Switzerland). The patient is a 58-year-old man who lives in Paris He was diagnosed four decades ago with retinitis pigmentosa, a progressive neurodegenerative disease that destroys light-sensitive cells in the retina and causes complete blindness. After treatment and after a period of adaptation and learning to use technology, The patient was able to locate, recognize, and count the various objects Using the treated eye while wearing glasses.
The man could not visually detect any objects before the injection or without glasses after the injection. “Hope it’s a breakthroughFirst author José Alan Sahel of the University of Pittsburgh and the Sorbonne said that the eye is “an extremely complex system that allows our vision to adapt to different levels of light.” Very fragile, so “when the vision disappears,” he noted, “there are few treatments, except for the use of prostheses or the reactivation of the remaining cells in the retina.”
Retinitis pigmentosa is caused by mutations in more than 71 different genes, leading to the development of gene therapies that replace a small number of proteins to repair broken cellular machinery It is tricky and not very effective. So the team approached the problem from a different angle: Instead of fixing mutated genes one by one in cells that respond to light by activating retinal neurons, they decided to directly activate neurons, which they used. Opto-Genetic Tools.
The team injected one of the patient’s eyes A vector associated with an adenovirus that carries genetic information, Which encodes a photosensitive protein called ChrimsonR channelrhodopsin, which is found in nature’s shiny algae. This protein responds to light by changing its shape and allowing ions to flow in and out of cells, which activates them, and in the case of neurons experimentally designed to express the rhodopsin channel, causes them to be released and the signal to be transmitted through the nerve endings to the brain.
Scientists have devised a way to convert light bouncing off objects in our environment into a single wavelength of the amber spectrum
Researchers chose ChrimsonR due to its preference for activation by amber light, which is safer and causes less pupillary constriction than the blue spectrum. The target was retinal ganglion cellsThat is, neurons that capture signals from the sticks and rods and transmit them through the optic nerve to the brain, where this information is processed to be perceived as a visual image. Scientists to activate ganglion cells in this way They have devised a way to divert the light that bounces off objects in our environment With a single wavelength of the amber spectrum, they used special glasses equipped with a special camera.
The University of Pittsburgh said in a statement that this camera captures images from the visual world and converts them into light pulses that are projected onto the retina in real time to activate the modified cells during visual tasks. “It takes time to adjust to the use of glasses,” Sahl recalls. At first, the patient didn’t find them very helpful, however After a few months, he began to see the white lines of the pedestrian crossing After several training sessions, he was able to learn about other things, big and small.
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