AEVR International AMD Awareness Week Congressional Briefing: Research Suggests AMD as Multiple Biological Diseases
Gregory Hageman, Ph.D. (Moran Eye Center, University of Utah), speaks
On September 20, AEVR—and partners AMD Alliance International, Alliance for Aging Research, Association for Research in Vision and Ophthalmology (ARVO), European Vision Institute, and Lighthouse International—sponsored a Congressional briefing in recognition of International Age-related Macular Degeneration (AMD) Awareness Week 2012. Since AMD is the leading cause of blindness and low vision in the developed world due to the loss of central vision, events held globally this week recognize its impact in terms of decreased productivity, loss of independence, and reduced quality of life. However, with each year, there is encouraging new research into diagnostics and treatments for this disease in which the macula, the central part of the light-sensitive retina in the back of the eye, deteriorates due to the deposit of proteins called drusen in the dry form of the disease and in the later stage neovascular form, which involves the proliferation and leakage of blood vessels.
Featured speaker Gregory Hageman, Ph.D., who serves as the Executive Director of the Center for Translational Medicine at the John A. Moran Eye Center at the University of Utah, spoke about his two-plus decades of National Eye Institute (NEI) funded research into AMD, which he describes as one of the best characterized genetic diseases due to a convergence of clinical, biological, and genetic data, the latter of which was derived from the National Institutes of Health (NIH)-funded Human Genome Project. He noted that he has spoken twice on Capitol Hill about his research—in 2005, when his and three other research teams first identified gene variants in the Complement Factor H (CHF) gene on chromosome 1, which is engaged in the control of a portion of the bodys immune system, after early studies of drusen composition showed that the complement system was dysfunctional in early AMD; and in 2008, when he reported on the discovery of a second major gene locus on chromosome 10 which, when combined with the CHF variants, accounts for approximately 90 percent of risk for developing the disease, as well as the first generation of Food and Drug Administration (FDA)-approved drugs to inhibit neovascularization.
He noted that a refined understanding of genotype and phenotype associations-clinical, biological, pathological-in disease development is a critical step toward the development of effective diagnostics and therapies. In that regard, his research suggests that AMD is likely multiple diseases with substantial overlap and that it co-segregates with other major systemic diseases. He reported that late-stage AMD can develop independently from either the chromosome 1 or the chromosome 10 genes and that some individuals can develop late-stage AMD in the absence of drusen. This has led him to propose that macular drusen are not significantly associated with pure Chromosome 10-directed AMD. As evidence, he notes that AMD in African Americans is associated with drusen, but neovascularization is rare, likely due to a scarcity of chromosome 10 gene variants, while AMD in Asians is primarily neovascular and drusen are uncommon, likely due to a scarcity of chromosome 1 gene variants.
Additionally, he discussed the association between reticular pseudodrusen and late-stage AMD. Reticular pseudodrusen are macular lesions that are similar in size and distribution to unique choroidal (a vascular layer next to the retina) capillaries called the choriocapillaris. Although the lesions had previously been thought to be AMD-related drusen, advances in imaging techniques have demonstrated it as a separate disease phenotype. In a Utah cohort, the reticular pseudodrusen phenotype is significantly associated with nearly 70 percent of all severe late-stage AMD, is female predominant, and can occur in the absence of both chromosome 1 and chromosome 10 gene variants, suggesting that it may be a new AMD disease entity.
Armed with these data, Dr. Hageman is directing a team of clinicians and researchers to identify and validate therapeutic targets for early-stage AMD and its co-segregating diseases, thereby shortening the drug-development process. There is a compelling national need to develop diagnostic tests and therapeutics to treat and prevent this devastating condition, he concluded.
AEVRs briefing featured an eye healthy luncheon, in which food items were identified for their nutritional content of zinc, antioxidants, omega-3 fatty acids, beta carotene, and lutein/zeaxanthin. These nutrients have been identified in the NEIs Age-related Eye Disease Study (AREDS) Phases 1 and 2 as critical to reducing the risk of developing AMD.
The event was supported by an unrestricted educational grant from Regeneron.
Left to right: Jenny Wilson (Moran Eye Center, University of Utah), Dr. Hageman, Michael Duenas, O.D. (American Optometric Association), and Matt McMahon (Senior Advisor for Translational Research, National Eye Institute)
Left to right: Michael Maroni (Alliance for Aging Research, a briefing co-sponsor) with AEVR Executive Director James Jorkasky
Left to right: Tom Zampieri, Ph.D. (Blinded Veterans Association) and veteran Steve Baskis, who attended the briefing between visits with Congressional offices, with James Jorkasky