Retinal lesions are a common cause of vision loss. These include, for example, macular degeneration, in which the photoreceptors of the most important part of the retina die off.
Photoreceptors are cells that are sensitive to light. They “process” it into nerve impulses, which are then transmitted to the brain and recognized there. Photoreceptor damage is irreversible.
To treat retinal degeneration, scientists are developing gene therapy. However, it is likely to be effective only for those people in whom this disorder is hereditary.
Another new, experimental, approach to the treatment of damage to photoreceptors is the use of stem cells. Scientists from the University of Wisconsin at Madison in 2012 were able to grow human retinal tissue in a laboratory from a wide spectrum of stem cells (pluripotent). Almost any tissue in the body can be created from such cells.
“While the ability to create ‘spare parts’ – these photoreceptors – was a breakthrough, it was still necessary to place them in the right way so that they could effectively repair the retina. We started thinking how to get these cells [к сетчатке] in a smarter way. Then we turned to engineers from our university, ”said ophthalmologist David Gamm, a professor at the University of Wisconsin and co-author of the 2012 study and new research paper.
Scientists have investigated a variety of synthetic materials that could potentially be used to support photoreceptor cells. They sought to find material and a suitable structure that could potentially be implanted under the retina to repair it. In 2012, scientists grew retinal cells in wine-glass-shaped cavities. Such form and technology were poorly suited for practical work.
The new matrix for future photoreceptors was made in the shape of an ice cube tray. This comparison is used by the scientists themselves. It is capable of carrying 300,000 stem cells. A small hole is provided under each of them, through which the cell, after becoming a photoreceptor, can connect to the retina.
The stem cell base was made from polyglycerin-sebacate. It is a fairly strong biocompatible substance that can be safely “absorbed” in two months – after it plays its role. Scientists suggest that it is the ideal material for such a purpose.
In the future, scientists plan to improve the shape of the matrix for cells. According to them, the technology is almost ready for testing on large animals. If such studies are successful, the method for treating retinal lesions could be tested in humans.