Previous research in mice with Retinitis Pigmentosa (RP) had shown that light-sensing cells in the retina, photoreceptors called rods and cones, slowly die over the years. During their gradual death, retinoic acid is released and it causes problems for cells that send visual information to the brain (retinal ganglion cells). This is described by the scientists as a sensory “noise” that interferes with the surviving photoreceptors of the inner retina and their ability to communicate with the brain, therefore obscuring vision.
However, a new study conducted by a group of scientists in Kramer Lab at UC Berkeley, led by Professor of Molecular and Cell Biology, Richard Kramer, seems to give a possible solution to the problem. Disulfiram, also called Antabuse, is a drug commonly prescribed to treat alcohol use disorder. When the researchers treated mice with disulfiram they found that nearly-blind mice, were much better at detecting images on a computer screen. They discovered the drug works to decrease the production of retinoic acid, therefore “cancelling” the sensory noise and allowing the surviving photoreceptors in the outer retina to complete the signal to the brain and ultimately restore some vision.
First author Michael Telias, Ph.D., Assistant Professor of Ophthalmology and Neuroscience, says “We knew the pathway that the drug disulfiram blocks to treat alcoholism was very similar to the pathway that’s hyper-activated in degenerative blindness (…) We expected some improvement, but our findings surpassed our expectations. We saw vision that had been lost over a long period of time preserved in those who received the treatment.”
The next step for researchers is to combine their studies with clinical trials conducted by ophthalmologists testing disulfiram on patients with inherited disease retinitis pigmentosa (RP). The trial would be carried out on a small set of people with advanced, but not yet complete, retinal degeneration. Their hope is that it might revive sight in humans with RP, and perhaps in other vision disorders, including age-related macular degeneration.
Michael Telias, Kevin K. Sit, Daniel Frozenfar, Benjamin Smith, Arjit Misra, Michael J. Goard, Richard H. Kramer. “Retinoic Acid Inhibitors Mitigate Vision Loss in a Mouse Model of Retinal Degeneration.” SCIENCE ADVANCES, 2022, 18. https://www.science.org/doi/10.1126/sciadv.abm4643