Researchers at the Nuffield Laboratory of Ophthalmology at the University of Oxford have experimentally shown in mice that it is possible to use gene therapy to reprogram cells and reverse serious vision problems, including blindness. The treatment would be applied to patients with deterioration of the retina , the inner layer of the eye where the photoreceptors that detect light stimuli and send them to the brain are located.
One of the main eye problems associated with age is macular degeneration , which, as its name suggests, affects a part of the retina called the macula. Although it occupies only 5% of the retinal surface, it is responsible for capturing central vision, fine details, colors and movement.
When a disease such as retinitis pigmentosa, the main cause of blindness in young people, or the passage of time destroys the photosensitive nerve cells, they do not disappear and, in theory, could be “resuscitated”. That was the goal of scientists at the University of Oxford, led by Samantha de Silva, who have used a modified virus as a vector for the cells of the retina of laboratory animals, suffering from retinitis pigmentosa, to express a protein called melanopsin , sensitive to light .
After the treatment, de Silva and his colleagues observed the rodents for a year and found that they were able to distinguish objects . That is, the ocular cells with melanopsin captured the light and sent the signals to the brain, as the researchers explain in the journal Proceedings of the National Academy of Sciences . Previously, the same team had successfully tested a prototype electronic retina in blind patients, but the new genetic modification technique would be easier to implant. The next step, as de Silva points out, will be to test it with clinical trials in human patients.
Spectacular advances
This announcement comes shortly after the US Food and Drug Administration (FDA) first tested a gene therapy for commercial use this summer , nearly thirty years after the first experiments in this field were conducted. The treatment given the green light by the FDA consists of extracting cells from the immune system (T lymphocytes) of patients with leukemia to insert a gene that modifies them and, after injecting them again, it targets cancer cells directly.
Although the new therapeutic technique, called Kymriah and produced by the Novartis company, has significant side effects, the results support it: 83% of 63 affected by acute lymphoblastic leukemia who did not respond to conventional therapies and were treated with Kymriah experienced a recovery . The problem is cost: Each injection costs $ 475,000.
Kymriah joins other gene therapies that have also been successfully tested and approved in Europe or China. In 2016, for example, a team of researchers from the San Raffaele Telethon Institute for Gene Therapies in Milan, Italy, announced that it had completely cured 18 children of a very rare disease , severe combined immunodeficiency due to adenosine deaminase deficiency, after extract his bone marrow and insert a gene to generate the enzyme whose deficiency caused the ailment. If we add these advances to the findings of the Oxford researchers and the development of CRISPR, the revolutionary tool for gene editing, this area of biomedicine seems to finally start to deliver on its promises .
