Swiss scientists have successfully restored vision to blind mice by introducing engineered light-sensing proteins into their eyes via a process known as optogenetics.
Experts hope this research can eventually be used in humans as a way to permanently reverse the effects of acquired blindness.
What our brains interpret as vision is actually the response of specialized cells in the eyes, known as retinal cells, to light stimuli. In those who were not born blind but rather acquired blindness over their lifetime, these retinal cells no longer function correctly because their light-sensing proteins are damaged. In the study, currently published in PLOS Biology, a team of researchers from the University of Berne in Switzerland attempted to replace the non-functioning cell parts with their own lab-engineered proteins, which they named Opto-mGluR6.
What sets Opto-mGluR6 apart from light-sensitive proteins occurring naturally in the eye is that these are particularly resilient to the effects of light, according to the press release. This means that their strength remains constant regardless of how much or how often they are hit with light. While Opto-mGluR6 is not the first lab-engineered light-sensitive protein, it differs from past models because it does not require a potentially damaging amount of light intensity in order to function.
“The major improvement of the new approach is that patients will be able to see under normal daylight conditions without the need for light intensifiers or image converter goggles,” said Dr. Sonja Kleinlogel, one of the study authors, in the press release.
Along with working under normal light stimuli, this novel protein also differs from past models because it is likely to be “invisible” to the host’s immune system, iflscience reported. This invisibility is advantageous because it means that the host’s body will likely not recognize the protein as an invading entity and unleash an attack.
The team introduced the engineered proteins into the eyes of blind mice using a modified virus. This method ensured that the protein could go directly to the surviving vision cells located deep within the eye. Opto-mGluR6 then replaced the no longer functioning photoreceptors and, in turn, restored the animals’ vision.
The results are promising and the team hopes to reproduce the effects in human subjects.
“The new therapy can potentially restore sight in patients suffering from any kind of photoreceptor degeneration,” Kleinlogel said. “For example, also those suffering from severe forms of age-related macular degeneration, a very common disease that affects to some degree about one in every 10 people over the age of 65.”