Even when scientists around Jose Coast Speaking of the University of Pittsburgh as a “milestone,” much remains to be done to arrive at a complete cure. A patient treated with gene therapy cannot perceive any colors and also needs special glasses to orient themselves in their environment.
Optogenetics as a treatment
The latest issue of the coast in the trade magazine Nature Medicine In any case it appears: the so-called optogenetics provides new possibilities for treating retinal diseases such as Retinitis pigmentosa – A completely unexpected result, because so far optogenetics has been used mainly in basic neurobiological research.
The basic principle: It directs a light-sensitive protein into the nervous system and then controls the behavior of individual neurons with a light signal to learn more about its function. This method is 20 years old and is now considered the laboratory standard for animal experiments. What is new is the discovery that a different type of this approach is also apparently suitable for targeted repair of the human retina.
In the case of the 58-year-old patient, scientists smuggled the gene for a light-sensitive algal protein into his eye with the help of a virus, where – according to the idea – it was supposed to take over the function of optical pigments that no longer exist. It worked, too, Sahl and his colleagues wrote in their study, but a few tricks were necessary. Since the protein is not particularly sensitive to light, the patient needed high-tech glasses that, on the one hand, amplify the incident light, and on the other hand – to protect the retinal tissue – pass only a suitable wavelength of 600 nm into the eye.
“Suddenly he saw lines”
With the help of glasses and proper training, the patient was already able to recognize strong contrasts and simple objects, such as glasses on the table.
Study director Sahl said at a press conference that after 40 years of losing his sight due to nephritis pigmentosa, the patient was able to see something again for the first time. “At first our patient couldn’t see anything, but after a few months he suddenly saw lines in the street – he could see the zebra crossing. He was very excited. Maybe we are more.”
Researchers were also able to prove that the photoresist got where it was supposed to. Scans by EEG show that the visual center of the test subject was active during the experiments. After all these years, his brain did not lose the ability to usefully process and interpret signals from the optic nerve.
The post is also popular with the professional community. James Bainbridge of University College London attests that the study is “of high quality” and that John Flannery of UC Berkeley considers it “an important step”, encouraging particularly that treatment “must be permanent and safe, and that is the most important point”.
In the Clinical study A total of eight volunteers participated; Researchers have not yet been able to conduct any tests with the other seven people who have been tested for the pandemic, and these tests should be done soon. It may be possible to expand vision-based therapy so that patients can see colors again. Sahel said at the press conference that the attempts are optimistic, but that the treatment also has its limits. We do not want to raise excessive hopes. For face recognition, you need a much higher resolution – we cannot do it with our method. “