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Pigmentary retinosis looking through the tunnel

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Dogs help the blind. It is a known story, but there are new versions. In one of them, an American veterinarian of Cuban and Basque origin returned the ability to see a blind dog. To obtain the miracle, the researcher used the research work of years, of his collaborators and of the gene therapy. His work was so great that other researchers began to experiment with similar humans. The results were not as good as with dogs, but they were encouraging...

One of the dogs, the first who was intervened, was called a gentleman: Lancelot. Pigmentary retinosis disease left her blind until 7 years ago gene therapy helped her to regain her sight. Since then, in his exams and tests highlights that Lancelot sees him as well as any other healthy dog. He recovered his vision at the University of Pennsylvania thanks to a treatment developed by Gustavo Aguirre's research team. Because both, in addition to recovering sight, first opened the way for other dogs and then the way for people.

The designation of retinosis pigmentaria includes a set of hereditary diseases that affect the eyes. They are degenerative diseases that cause the progressive loss of vision. Initially they affect external or peripheral vision and night vision: patients see it as if they look outside a tunnel. In some cases, the disease becomes blindness over time. It is considered a rare disease, since the number of people affected by each variant, with so many variants, is not very high.

The retinosis damage the retina; hence the name. The retina, besides covering the inside of the eye, takes the images that surround it, processes them and sends them to the brain through the optic nerve. In the retinosis pigmentarias some of the retina cells are gradually destroyed, especially photoreceptors, appearing accumulations of pigments inside the eye. As a result, the view is decreasing, spending.

In research

Studies carried out in molecular biology have revealed the existence of different types of pigmentary retinosis. According to recent studies, there are at least 190 genes related to this disease, and it would not be surprising that new genes were discovered. As if it were not enough, each of the genes can have a large number of mutations, many times more than a hundred. Consequently, most of those who present pigmentary retinosis have different mutations in different genes.

The complexity of the disease is evident. The variability of genes increases the complexity of treatments that could occur in the future. And there is a certainty among researchers that it increases the degree of complexity: many of the genes that cause retinosis pigmentosa also affect other diseases of the retina.

Since, for the time being, it is not possible to observe the broad genetic universe as a whole, researchers are selecting one area or another and looking into it. Among them is the Experimental Ophthalmology Group of the UPV, under the responsibility of Professor Elena Vecino. This team fights against degenerative diseases of the retina.

They collaborate with Gustavo Aguirre, a researcher who has given the sight to Lancelot and other dogs who have come after.

The UPV ophthalmology team has also worked with animals: They investigate dogs with the mutation of the protein RPE65. The RPE65 protein is found in the retinal epithelium, along with photoreceptors, and researchers know it is fundamental to be able to see it well. When failures occur in this protein, photoreceptors do not function, patients enter the dark tunnel and it is impossible to see them.

Elena Vecino's research team has shown that the alterations that occur in the canine and human retina are similar. Until now, the researchers knew that in the retinosis the organization of photoreceptors was altered and that they appeared there where they should not be. They discover that the same occurs in animals. Another of the conclusions of the studies was to know that the structure of the retina in general is maintained, that it is not destroyed and that the altered cells do not disappear. Damage yes, but not at all. This has made researchers think that there may be more than one way to perform a proper therapy.

During the last year, UPV researchers have been studying to what extent the damage produced in the retina can be repaired by gene therapy. In short, they have shown that the virus injection technique that causes the production of RPE65 can be a suitable treatment, since the retina is recovered, but only when this injection occurs under the retina. If done so, the animals regain sight and no side effect occurs in the eye.

In view of the excellent results of these and other animal research, there has already been a leap in research in gene therapy with humans. For the moment, the results of the trials have been encouraging, but only encouraging.

Other treatments Other treatments

Although the effect of gene therapy on retinosis is evident, it is not the only strategy being applied against this disease.

Among the drugs, for example, neutrophic factors are being used, that is, a set of natural proteins that help keep cells alive and healthy. In the trials that have been carried out in animals, results have been obtained, which have been taken into account, and are currently working on the development of continuous, slow release devices. Encapsulated cells would be an example of this. In this therapy, a small device is placed in the eye. The device carries CNTF proteins from the retina that are slowly released. If everything goes well, the death of photoreceptors is avoided and, therefore, the loss of vision. In this line of research, we are working to find more neutrophic factors, to understand how they affect retinal cells, to know if they can act on other diseases of the retina, and to study new techniques of integration in the eye of neutrophic factors.

Research on vitamin A in the field of food has gained a lot of strength, since in some studies have shown that with the daily intake of this vitamin the retinosis advances more slowly, but the information on the possible benefits of this treatment is minimal. The retinal cell transplants, the programming of stem cells, the surgery... are mentioned among the possibilities of curing the retinosis, but so far there is no adequate treatment for people with retinosis, let alone the way to cure the disease. Man is more complex than the dog, pigmentary retinosis, and the solution will be complex. But the end of the tunnel is underway.