Restore the vision of blind mice with light-activated drugs

BarcelonaSome 200 million people worldwide suffer from a disease that causes blindness due to the malfunction of photoreceptor cells, which are responsible for detecting light in the eye. Although the rest of the retina functions, the brain is unable to process vision because it does not receive light signals. Now, researchers from the Institute for Bioengineering of Catalonia (IBEC) have led a study in which they have managed to restore the vision of blind mice with a new class of drugs called photosensitive drugs, a type of medication that is activated precisely by light. According to its authors, the research published this Wednesday in the journal Journal of the American Chemical Society (JACS) represents "a major step forward" in the search for treatments to restore vision in humans.

These drugs can assume the role of non-functioning photoreceptor cells and allow the mouse's brain to process vision. Pau Gorostiza, ICREA research professor at IBEC and co-leader of the study, highlights that the molecules they use are very effective in restoring sight and the method they employ is "very simple" compared to other treatments. However, he emphasizes that "these molecules do not cure blindness, as they do not address the cause of photoreceptor degeneration," but rather perform their function.

So far, strategies against these diseases include gene therapy, which is only effective for a very small group of patients with very specific mutations, and electronic retina prostheses, which are "invasive, costly, and require extensive training for their effective use," according to IBEC. Therefore, they highlight the potential of their discovery, which they have so far only demonstrated in mice, because it does not require genetic manipulation or the implantation of devices. The work has been carried out jointly with the University of Alcalá, the Institute of Advanced Chemistry of Catalonia, the University of Barcelona, the Ramón y Cajal Health Research Institute, the Autonomous University of Barcelona, and the Eduard Soler Foundation.

"A great therapeutic opportunity"

Researchers have created molecules called prosthe6 that physically change shape when they receive light. In these diseases that cause blindness, the cells that detect light stop working, but the rest of the retina that sends the signal to the brain does work. These molecules take advantage of the retina's working structure and, when light enters the eye, they activate as if they were photoreceptor cells and send the image signal to the brain as a healthy eye would. "In degenerative eye diseases, even though photoreceptors are lost, a large part of this underlying circuit remains intact, but inactive. This creates a great therapeutic opportunity," explains Pedro de la Villa, a researcher at the University of Alcalá and co-leader of the study.

Turning this into a therapy, however, is a "long and complex" process, explains Gorostiza. Likewise, the authors believe that with these results there is a "realistic possibility" of restoring high-quality vision through these drugs. This would be done "non-invasively, reversibly, and with a mechanism independent of the specific retinal disease or genetic mutation, which would allow reaching the majority of patients," highlights Gorostiza. The technology is patented and researchers are now evaluating its safety. They are also working with the company Eyelumina to secure future clinical trials and support in development.