Thanks to gene therapy, it was possible to replace damaged visual cells in the eyes of mice, Current Biology reports.
The new method of treatment is based on the use of cells in the deeper layers of the retina to detect light. In the healthy eye, specialized cells – rods and cones – respond to light to produce electrical signals. In contrast, the deeper ganglion and bipolar cells are responsible for processing these signals and sending them to the brain. It seems that by inducing these cells to produce their own visual pigments, rods and suppositories can be replaced to some extent.
The scientists used the human gene for rhodopsin, a dye that allows the rods to respond to brightness levels. They combined it with a genetic “switch” that activates the gene only in ganglion and bipolar cells, and then, using a harmless virus, introduced the DNA prepared in this way into the eyes of mice with damaged suppositories and rods.
The method proved so effective that when they saw the video of an owl, the rodents sought shelter – just like those who had normal eyesight. A control group of untreated blind mice did not escape.
Also, distinguishing the size of objects was quite good for the mice after treatment, although not as well as for the healthy mice (the white and black stripes distinguished by the treated mice had to be ten times thicker).
The new method is intended to treat all kinds of blindness caused by damage to or destruction of rods or suppositories. Previous attempts at gene therapy for vision loss have focused on replacing defective genes for rarer specific forms of congenital blindness, such as Leber’s hereditary optic neuropathy.
It was also the first time that a human gene was used. The virus used to introduce it into cells was approved for human use, and scientists hope to begin human research within five years. It is not known how long the effects of the treatment could last.