The zebrafish, also known as zebra danio and Danio rerio, is a very special kind of fish. Found in most aquariums, it is also used by scientists as a model organism in research on vertebrate development and gene function. And quite amazingly, the zebrafish actually has the ability to regenerate the retinas of its own eyes! It was while studying this particular attribute that scientists believe they found a cure for blindness. Most cases of blindness are attributed to lesions to the retina caused by diseases such as macular degeneration, diabetes and glaucoma.
While studying how the zebrafish regenerates its retinas, British scientists discovered a type of stem cell in the eyes of this fish. The same stem cells are also found in the eyes of mammals. The scientists were able to harvest and successfully grow the stem cells in laboratory. Once transplanted into the retina, the stem cells develop into neurons. The neurons found in the retinas are specialized cells that carry information from the eye to the brain and from the brain to the eye, allowing us to see. There are many types of neurons, each with its own specific role.
According to scientists, humans also possess such stem cells. They are called Mueller glial cells. It is possible to harvest these cells quite easily, grow them in laboratory and re-inject them into the retina.
Having tested this procedure on rats with diseased retinas, researchers are now ready to begin testing their discovery on humans.
Researchers are hoping to be able to perform autologous transplants in a couple of years. That is to say, they will use a person’s own stem cells to restore their sight. Scientists will harvest stem cells from the eye of a blind individual, grow them in laboratory and inject them back into the eye, thereby restoring sight.
Because these cells can be grown in laboratory so easily, researchers believe that some day, we will have stem cell banks accessible to anyone who has become blind because of damaged retinas. To ensure compatibility, scientists will use the typing system used for blood transfusions.
What an incredibly hopeful discovery!