The treatment is based on the properties that cells have when the body is developing as an embryo. At that time, cells can repair and regenerate themselves, but that capacity declines rapidly with age. The scientists reasoned that if cells could be induced to return to that youthful state, they would be able to repair damage. To turn back the clock, experts modified a process usually used to create the “blank slate” cells known as induced pluripotent stem cells. Those cells are created by injecting a cocktail of four proteins that help reprogramme a cell. To restore cells to a more youthful state, they tweaked the cocktail, using just three of the “youth-restoring” proteins — dubbed OSK. They targeted the retinal ganglion cells in the eye, which are linked to the brain through connections called axons.
These axons form the optic nerve — and damage to them caused by injury, aging or disease causes poor vision and blindness. To test the effects of the cocktail, they first injected OSK into the eyes of mice with optic nerve injuries. They saw a twofold increase in the number of surviving retinal ganglion cells and a fivefold increase in nerve regrowth.
With signs OSK could reverse damage caused by injury, the team turned to countering the effects of disease — specifically glaucoma, which is the leading cause of blindness in humans. They replicated the conditions of the disease, where a build-up of pressure in the eye damages the optic nerve, in several dozen mice. Those who received the OSK treatment saw “significant” benefits, according to the study published in the journal Nature.