Current Data on the Age-Related Macular Degeneration Pathophysiology: Focus on Growth Factors and Neurotrophins

Abstract

Age is a main risk factor for age-related macular degeneration (AMD), a complex multifactorial neurodegenerative retinal disease that is becoming the leading cause of vision loss in people over 55 years in developed countries. The risk of developing and rate of progression of AMD, as well as response to therapy, depend on the interaction of multiple genetic and environmental factors. In advanced stage, AMD is classified into dry atrophic (dry) or neovascular (wet) form. Intravitreal injection of anti-vascular endothelial growth factor agents is currently the first-line therapy for neovascular AMD. Unfortunately, therapy for dry AMD is still challenging, owing to an insufficient knowledge of the exact pathogenetic mechanisms. Considering the heterogeneity of AMD and the complexity of influencing age-dependent physiological processes, aging and immune disorders, the most realistic seems to be the further development of antiangiogenic therapy with an expansion of the range of targets, prolongation of their action and improvement of the delivery system. The neuroprotective potential of exogenous neurotrophins for retinal neurons has been proven; however, in order to develop effective drugs for the dry form of AMD based on them, it is necessary to resolve the issue of ways to effectively deliver them to the retina. In this review we discuss the current data on the AMD pathophysiology with focus on the role of vascular growth factors and neurotrophins.