Restoring Lost Sight May Become a Reality

Zebra fish may open up an opportunity in preventing, or reversing blindness. A special type of cell found in the eye of zebra fish has been found to be very important in regenerating the retina, and restoring vision even after extensive damage. These stem cells are called Muller glial cells, and scientists believe they may be able to use these cells to regenerate damaged retinas in humans. The retina is the part of the eye that receives light, and transmits images to the brain. When damaged through Glaucoma, Macular Degeneration and Diabetic Retinopathy to name a few, the individual loses their vision permanently.

Just why zebra fish have an abundance of these adult stem cells to regenerate their retinas, while they are very rare in humans remains a mystery. British researchers have successfully grown in the lab this type of adult stem cell that develops into neurons in the retina. These cells could be injected into the eye as a treatment for retina damaging diseases. When tested in rats with diseased retinas, the cells migrated into the retina and took on the characteristics of the surrounding neurons. Researchers are now looking at developing this approach for use in the human eye.

In addition to growing the cells in the lab and transplanting them back into the eye, the researchers are looking at ways to stimulate growth and influence the eye to repair itself using its own cells. Using one’s own cells rather than a donor’s has the advantage that the immune system is less likely to reject the treatment. Although Muller glial cells are present in the human eye, it is not clear why they do not automatically repair the retina. It is possible that internal mechanisms exist in the normal adult retina that prevents these cells from dividing and replicating. The next step is to identify which factors are responsible for blocking the regeneration.

Researchers hope that this research may lead to a treatment within five to ten years, for cells isolated from a person’s own eye. However, the need to overcome the immune response for transplantation of a donor’s cells means that this second approach would take longer. In any case, a treatment for diseases such as macular degeneration, glaucoma and diabetes-related blindness seems to be right around the corner. Dr Astrid Limb, who led the study states. ‘Our findings have enormous potential.’ ‘It may be possible to store the cells in a cell bank and transplant them into the eye or to use cells from a person’s own eye.’ .