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Researchers delve into role of nutritional supplements in AMD treatment
As the retina community awaits results of AREDS2, a physician advises colleagues to use study data to educate patients about disease severity and prognosis.
Ongoing clinical studies highlight the role of nutritional supplements in managing and mitigating dry age-related macular degeneration.
Physicians need to keep abreast of new data on the effects of nutritional supplements on the progression of dry AMD toward more advanced forms, such as exudative and geographic atrophy phenotypes, Raymond Iezzi, MD, MS, said.
“I think that the role of nutrition, lifestyle, light exposure and genetics is still an area of active investigation. Clinicians need to continue to maintain their study on the latest developments,” he said.
At the 2012 Mayo Clinic Retina Update and Case Conference, Iezzi elucidated results of the Age-Related Eye Disease Study (AREDS) and outlined AREDS2, which is nearly completed. Both studies are sponsored by the National Eye Institute.
Raymond Iezzi, MD, MS, looks forward to the AREDS2 results, which add an assessment of omega-3 fatty acids to the original study.
In a subsequent interview with Ocular Surgery News, Iezzi emphasized the need for physicians to use data from AREDS and other studies to assuage patients’ concerns about disease severity and prognosis.
Iezzi also said that treatment hinges on a specific diagnosis of AMD. Spurious diagnoses can obscure disease pathology, hinder treatment and cause undue concern, he said.
“Vigilance in follow-up and treatment is strongly recommended,” he said. “If the term ‘age-related macular degeneration’ is used loosely, it’s going to cause a lot of undue worry and concern.”
AREDS trials
The first AREDS trial included patients with early, intermediate and unilateral advanced AMD. Patients received daily oral doses of antioxidants that contained vitamin C 500 mg, vitamin E 400 IU and beta carotene 15 mg; zinc 80 mg and copper 2 mg; antioxidants plus zinc; or placebo.
In patients with intermediate AMD or monocular advanced AMD, antioxidants reduced the risk of developing any advanced AMD by 17%, zinc reduced the risk by 21%, and combined antioxidants and zinc reduced the risk by 25%.
Sustained-release drugs, antioxidant drops, nutritional supplementation and immunosuppressants are all under investigation to determine their role in preventing progression of disease to geographic atrophy, pictured here with blue peak autofluorescence (left) and in color (right) for comparison.
Image: Heidelberg Engineering
“The AREDS study was a well-designed prospective trial aimed at determining if antioxidant vitamins and zinc have roles in slowing the progression of AMD. It’s the first trial that we have that was constructed in this fashion, and it gives us statistically significant data that identify an at-risk population for progression” Iezzi said.
Results of AREDS2 are scheduled for release in March or April.
“AREDS2 is going to be a very important study for ophthalmology because it’s going to add an assessment of carotenoids other than beta carotene and it’s going to give us an assessment of the role of omega-3 fatty acids, which we hadn’t had in the AREDS design in the past,” Iezzi said.
Other agents in clinical trials
Other investigations are ongoing. For example, Iezzi and colleagues are conducting a clinical trial for patients with bilateral geographic atrophy. Patients are being treated with the sustained-release fluocinolone acetonide implant, Iluvien (Alimera), which can elute a low dose of medication for up to 3 years.
The National Eye Institute is currently conducting a clinical trial on Sirolimus (rapamycin, Tocris Bioscience), an immunosuppressant, in which investigators are examining the role of mTOR inhibition in slowing the progression of geographic atrophy, Iezzi said.
Othera has completed a study of its antioxidant eye drop OT-551.
“If you review strategies for the treatment of dry AMD, they largely focus on enhancing the macula’s capacity to handle oxidative stress induced by everyday life,” Iezzi said.
Exploring pathogenic factors
Investigators are focusing on the cause and progression of geographic atrophy, Iezzi said.
“At this point, we really don’t have effective treatments to slow the progression of and enlargement of geographic atrophy and vision loss. But that doesn’t mean that there aren’t treatments out there, and it doesn’t mean that if it doesn’t work in geographic atrophy that it won’t work in patients with drusen that have not manifested advanced AMD,” he said.
Current treatments for dry AMD focus on oxidative stress, Iezzi said.
“Light incident upon the macula induces the formation of oxidant species. That’s why our maculas evolved to concentrate antioxidants in the foveola. We know that antioxidants are depleted in the maculas of patients with AMD,” Iezzi said.
Novel dry AMD therapies involve nanotechnology, Iezzi said.
“Some of our current research involves the use of nanoparticles that are capable of delivering neuroprotectants to the photoreceptors and retinal pigment epithelium, as well as anti-inflammatory drugs to dampen retinal neuroinflammation,” he said. – by Matt Hasson
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Perspective
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We certainly have good level 1 data on nutrient supplementation for people who have non-advanced macular degeneration from the AREDS1 to decrease the rate of conversion from eyes with drusen to those with neovascular AMD. What has not been shown, at least that I am aware, is that by giving nutrients we can prevent progression to the advanced form of non-neovascular AMD, which is geographic atrophy. Nor have we shown that giving people these nutrients can prevent geographic atrophy from progressing. In fact, there is some evidence that in at least one subtype of patients that has geographic atrophy that giving vitamin A could actually be harmful to that group. At least from the studies that we have, I would say there is good evidence that it can help prevent progression to the wet form but not to the advanced form of the dry form, which is geographic atrophy.
The original AREDS1 helps to validate the theory that oxidants are an important contributor to progression of macular degeneration, particularly progression to the wet form. One of the questions is whether we can come up with the ideal mixture or the ideal group of antioxidants or nutrient supplements to optimally prevent progression from the dry form to the wet form and to prevent progression from the non-advanced dry form to the advanced form, ie, geographic atrophy, or even to prevent the progression of geographic atrophy. Hopefully, the AREDS2 will answer some of that question.
To me, one of the most interesting things to come out of the AREDS2 is whether the AREDS1 can be replicated. One of the groups will repeat what was done in AREDS1. Hopefully, at least it will show that those results were valid. That will be an interesting thing to come out of the AREDS2.