Human induced pluripotent stem cells illuminate pathways and novel treatment targets for age-related macular degeneration
Age-related macular degeneration (AMD) is the most common cause of legal blindness in the United States and is the leading cause of visual impairment in the aging population, especially in those over 55 years of age. By 2020, an anticipated 196 million individuals will be affected with AMD (1). Geographic atrophy is characterized by a slow progressive degeneration of the retinal pigment epithelium (RPE), resulting in the gradual loss of photoreceptors. The wet, or neovascular, form is characterized by the growth of abnormal new blood vessels from beneath the retina that can cause severe and rapid vision loss due to hemorrhage and exudation. Most current treatments are directed against neovascular AMD and are focused against stimulators of angiogenesis (such as vascular endothelial growth factor). These treatments are limited in their applicability, require invasive intravitreal injections, which are burdensome for both patient and physician, and are not capable of preventing or reversing vision loss over the long term. Currently, there are no effective treatments for atrophic AMD.