Retinoid analogs and polyphenols as potential therapeutics for age-related macular degeneration

Progressive retinal degeneration manifesting as age-related macular degeneration (AMD) in the elderly affects millions of individuals worldwide. Among various blinding diseases, AMD is the leading cause of central vision impairment in developed countries. Poor understanding of AMD etiology hampers the development of therapeutics against this devastating ocular disease. Currently, daily intravitreal injections of anti-angiogenic drugs, preventing abnormal vessel growth are the only treatment option for wet AMD. However, for dry AMD associated with retinal atrophy, at present there is no cure available. Recent clinical research has demonstrated beneficial effects of plant-derived compounds for various eye disorders. Thus, the ongoing efforts toward discovering efficient treatments preventing or delaying AMD progression focus on implementing a healthy diet rich in vitamins, including vitamin A, E, and C, minerals and carotenoids, in particular lutein and zeaxanthin, to reduce the disease burden. In addition, studies in cell culture and animal models indicated therapeutic potential of dietary polyphenolic compounds present in fruits and vegetables. These natural compounds protect visual function and retinal morphology likely due to their anti-oxidant and anti-inflammatory properties. Although understanding of the exact mechanism of these compounds' positive effects requires further investigation, they provide non-invasive alternative to battle AMD-like condition. Additionally, studies carried in animal models mimicking AMD-like pathology, examining the pharmacological potential of particular retinoid analogs, demonstrated promising results for their use, and thus they should be considered as an option in developing therapies for AMD. In here, we summarize the most current knowledge regarding developments of therapeutic options to maintain ocular health and prevent vision loss associated with aging. Impact statement Age-related macular degeneration (AMD) is a devastating retinal degenerative disease. Epidemiological reports showed an expected increasing prevalence of AMD in the near future. The only one existing FDA-approved pharmacological treatment involves an anti-vascular endothelial growth factor (VEGF) therapy with serious disadvantages. This limitation emphasizes an alarming need to develop new therapeutic approaches to prevent and treat AMD. In this review, we summarize scientific data unraveling the therapeutic potential of the specific retinoid and natural compounds. The experimental results reported by us and other research groups demonstrated that retinoid analogs and compounds with natural product scaffolds could serve as lead compounds for the development of new therapeutic agents with potential to prevent or slow down the pathogenesis of AMD.