In some forms of blindness, much of the eye works fine, but the vision is perceived by damage to the photoreceptors in the retina, which is the first step in the visual chain. Because when they are activated by light, they transmit the stimulus to further areas of the nervous system, where it is analyzed. In higher organisms, there is talk of the visual path transmitting information to the visual cortex. Unfortunately, photoreceptors are damaged in many eye diseases, such as retinitis pigmentosa and age-related macular degeneration, and while the other vision mechanisms are working, the patient loses his sight.
Therefore, in this new study, scientists tried to bypass photoreceptors and activate neurons directly, and to do so, they had to act with a gene called MC01, which expresses opsins, a group of photosensitive G-protein coupled membrane receptors in photoreceptors and bipolar neurons . As the authors suggest, the beauty of this strategy is its simplicity, and what's more, adding the MCO1 gene to bipolar neurons in the retina with defective photoreceptors is done with one injection into the eye.
Scientists tested their solution in mice with damaged retina that did not respond to light at all. After treatment, the mice quickly regained light sensitivity and retinal function, as confirmed by numerous tests, such as navigating mazes and responding to changes in movement. The level of MCO1 in bipolar neurons remained high for six months after the injection, and most importantly, it did not change the levels of other proteins, i.e. it did not cause side effects, and there were no signs of inflammation in the tissue or blood.
And while the results are promising, there is a small catch here, namely, until we do human testing, we won't know exactly if such restored vision will work as effectively as normal vision, but even partial vision should still be better than total blindness. . Nanoscope wants to start human clinical trials in the US later this year, so we shouldn't wait too long for the results: - Human clinical trials will help us understand how a signal sent directly to bipolar neurons affects the quality of vision, such as the eye being treated it is able to capture fast-moving objects, explains Subrata Batabyal, who conducts the research.