WASHINGTON: Researchers from Ireland said Wednesday they have made a major breakthrough in finding a new treatment for the eye disease Age-Related Macular Degeneration (AMD) which can cause central blindness in sufferers, China's Xinhua news agency reported.
Researchers at Trinity College Dublin, Ireland, found that a component of the immune system called IL-18 acts as a guardian of eyesight by suppressing the production of damaging blood vessels behind the retina at the back of the eye.
In pre-clinical mouse models with AMD-like injury, it was shown that IL-18 can be administered in a non-invasive way, which could represent a major improvement on the current therapeutic options that are open to patients.
"We were initially concerned that IL-18 might cause damage to the sensitive cells of the retina, because it is typically linked to inflammation," said first author Sarah Doyle, assistant professor of Trinity College Dublin.
"But surprisingly we found that low doses had no adverse effects on the retina and yet still suppressed abnormal blood vessel growth."
AMD is one of the most common forms of blindness in the aging population. As the disease involves a loss of central vision, people suffering from advanced stages of the disease are unable to read, watch TV, drive or use computers.
There are two forms of AMD: dry and wet. Dry AMD accounts for the majority of cases, but wet AMD causes over 90 percent of blindness associated with the disease.
In wet AMD, blood vessels underneath the retina begin to grow abnormally, which causes almost immediate central blindness. Because central vision accounts for almost all of daytime visual acuity, wet AMD sufferers experience severe and profound day-to-day challenges.
Treatment options for wet AMD are currently limited to the end stages of the disease. Regular injections of antibodies must be made directly into the eye to mop up a problematic molecule termed VEGF.
However, the Trinity researchers found that IL-18 directly inhibits the production of VEGF itself, which hints that its effects may last longer than those from anti-VEGF therapies.
"Our findings...should lead to clinical deployment of IL-18 as a treatment for AMD in the short term," said Matthew Campbell, research assistant professor in genetics at Trinity.
The results were published in the U.S. journal Science Translational Medicine.