Scientists, with the help of genetic engineering methods, returned sight to a blind person, which recently seemed like science fiction. The RG correspondent asked the director of the Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Doctor of Biological Sciences Mikhail Firsov to comment on this sensation.
The message that a group of French and Swiss scientists returned sight to a completely blind person went around all the world media. It became a sensation, some presented it almost like a miracle: the blind man received his sight! Is it really so?
Mikhail Firsov: Well, about a miracle, it’s too strong. In fact, science already knows how to return vision to completely blind people. To do this, a special chip is inserted into the eye, with which a person can distinguish large objects. This is a very complex system, the operation takes about eight hours and is performed by a team of first-class doctors. Its cost is millions of dollars. As a rule, such operations are successful, but there is a serious but … The fact is that the chip does not work for a long time, it is overgrown with tissue, covered with mucus. Therefore, the chip will last a maximum of 2-3 years. And repeated operations are impossible.
That is, the epiphany does not last long. But in this case we are talking about a different technology?
Mikhail Firsov: Quite right. This is optogenetics, which has already been named one of the most promising sciences among those that have appeared recently. If a team of supervisors has to work eight hours to insert a chip, optogenetics will allow one to see the light in one injection into the eyeball, which even a nurse can do in any clinic. What is the essence of this technology? The genes are inserted into the neurons of the cells that encode the production of light-sensitive proteins. In particular, these are the so-called channel rhodopsins, which in 2004 were discovered in green algae. And by acting on these proteins with light, neurons can be controlled, which opens up the most unexpected prospects in various fields of science. For example, neurophysiologists are trying this method to treat epilepsy. It is known that during a seizure, the so-called synchronous waves are sharply increased in the brain. To suppress them, you can insert light-sensitive proteins into the brain and try to send a signal with light in antiphase and suppress these waves. So far, this approach is at the level of an idea, but it can turn out to be very promising.
New technology can treat epilepsy and deafness with light
As far as I understand, to combat blindness, the genes of these algae are introduced into the patient’s eye, and he sees. In fact, a new visual matrix appears in the eye, new rods and cones, about which we have known since school.
Mikhail Firsov: Yes. But the epiphany does not come immediately. It takes several months for a large number of light-sensitive cells to accumulate in the eye. But that’s not all. A person must be taught to see in the truest sense of the word. Yes, don’t be surprised to teach. The fact is that this situation is rather abnormal for the brain. He has new ways of processing information, the brain must adapt to them, and this requires training.
What does the one who has received his sight see?
Mikhail Firsov: At the moment, the authors of the study report that after seven months after the start of the trial, the patient was able to determine the number of different objects – for example, two to three notebooks lying on the table. The fact that the vision was working was also evident from the electroencephalogram, which indicated the visual activity of the brain. True, the ability to see returned only partially – the patient could not distinguish a face and could not read.
But if you inject more light-sensitive proteins, surely your vision will improve? That is, the path to human enlightenment is well-trodden. Now you just have to dig this “gold mine”?
Mikhail Firsov: This is what is now being done in many laboratories around the world, including our institute. Let’s say scientists are looking for new, more efficient proteins. And experiments have already been carried out on one of the types of proteins in which the photosensitivity is 100 times higher than that of green algae. In addition, various options for introducing genes into the eyeball are being considered. The fact is that there are three layers in the retina, and depending on where the light-sensitive proteins are injected, the effect can be different.
In this work, we are talking about a specific disease – retinitis pigmentosa. Could this technology help with other eye diseases?
Mikhail Firsov: Yes, such experiments are already underway. It should be emphasized that optogenetics does not heal the diseases themselves, but helps to eliminate their consequences. Perhaps this technology can be applied to the treatment of deafness. Insert light-sensitive proteins into the ear and work not on a sound wave, but on a light one. For this, a sound wave must be converted into a light wave and influenced by it on light-sensitive cells.
In 1979, one of the “fathers” of the DNA double helix, Nobel laureate Francis Crick, proposed using light to control a single neuron. It took more than 25 years for this idea to give birth to a new science of optogenetics and a revolutionary technology for breakthrough research in medicine.