Demystifying science | Hope for macular degeneration

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Two drugs against macular degeneration have just been approved in the United States and other molecules are in clinical trials. Macular degeneration is “an eye disease caused by damage to the macula which leads to the gradual or sudden loss of central vision,” according to the Quebec Macular Degeneration Association. The macula is the central area of ​​the retina.

“This year there have been two FDA approvals [l’agence de réglementation américaine des médicaments] drugs that prevent the immune system from attacking the retina,” explains Mike Sapieha, who heads the neurovascular eye disease research unit at Maisonneuve-Rosemont Hospital in Montreal. “This is in addition to medications that have appeared over the past 15 to 20 years and the validation of supplements that reduce the risk of macular degeneration. » These supplements combine vitamin C and minerals.

Medications that have existed since the beginning of the millennium slow the progression of the “wet” form, which represents 10% to 20% of cases of age-related macular degeneration (AMD). The two new drugs are the first to help with “dry” macular degeneration.

In all cases, AMD involves the deposition of particles behind the retina, which cause inflammation and deformation of the retina. The wet form, which progresses more quickly than the dry form, adds vascular problems which worsen the inflammation.

New drugs for dry AMD are awaiting approval in Canada. But Mr. Sapieha notes that injections of these new drugs are required every month, which could make it difficult to adhere to treatment. A minority of treated patients also saw their AMD worsen. His laboratory is working on several other molecules. A phase 2 clinical trial, the penultimate step before approval, has just taken place for one of these molecules. “We have positive results after a single injection eliminating damaged cells that cause inflammation. »

Stem cells

At the Montreal Clinical Research Institute (IRCM), neurobiologist Michel Cayouette is working on injections of stem cells replacing retinal support cells damaged by AMD. Other teams around the world are working on the same approach for photoreceptor cells in the retina, he notes.

Other Quebec researchers are working further upstream. “My research focuses on how particle deposits grow on the retina,” explains ophthalmologist Miguel Burnier of the McGill University Health Center (MUHC). His lab has also identified blue portions of sunlight that damage the retina.

Vincent Raymond, geneticist at the Laval University Hospital Center, studies genes that double or even triple the risk of AMD. “If you have a brother or sister who has AMD, we can tell you whether your risk increases or not,” says Dr.^r Raymond.

Smoking is the strongest risk factor for AMD, increasing the risk tenfold. Consumption of fish, or dietary supplements known as ARED (Age-Related Eye Disease), reduces the risk by a quarter, according to the large American study AREDS.