Macular degeneration affects more than 10 million Americans, making it the leading cause of vision loss. What is now considered an irreversible loss of vision could soon be a curable disease with stem cell therapy.
What is macular degeneration?
Also called age-related macular degeneration, this common eye disease is caused by deterioration of the back layer of the retinal pigment epithelium (RPE). As you can see in the diagram below, the retina is located in the back of the eye, and the macula is located at the back of the retina. The macula–responsible for your central vision–is filled with rods and cones, or photoreceptor cells that react to light and send images to the brain. The RPE supplies these rods and cones with nutrients and removes waste. The deterioration of the RPE results in a loss of central vision.
How can stem cell therapy help?
Stem cell therapy has helped scientists and doctors better understand how these cells work together. This assists with the exploration of replacing these cells via stem cell therapy to cure eye diseases like macular degeneration. This procedure is extremely complex, as the rods and cones are connected to tiny nerve fibers that allow signals to be transmitted to the brain. If the RPE cells are replaced before the rods and cones are completely lost, the transplanted RPE cells could prevent them from dying, enhance central vision and reverse the disease.
What do studies show?
There are many different stem cell studies being done to try and combat macular degeneration. Some scientists are using induced pluripotent stem cells, or adult stem cells that are induced to act like embryonic stem cells. This ensures the stem cells are not tissue-specific and can be used to grow rods, cones or RPE cells. Others are experimenting with tissue-specific RPE cells from eyes that have been donated to eye banks.
There is one study in particular that has great implications. Scientists harvest stem cells from mice and create induced pluripotent stem cells. These stem cells are then used to grow new tissue, which is transplanted into mice suffering from retinal degeneration. More than 40% of mice regained the ability to see light after the procedure.
Today, macular degeneration is still widely considered an irreversible disease. Thankfully, the studies being done thus far are demonstrating profound results. While it is still a fairly new discovery, doctors and scientists have very high hopes.