Perspective on AMD Pathobiology: A Bioenergetic Crisis in the RPE

AMD is the leading cause of blindness in developed countries. The dry form of AMD, also known as atrophic AMD, is characterized by the death of RPE and photoreceptors. Currently, there are no treatments for this form of the disease due in part to our incomplete understanding of the mechanism causing AMD. Strong experimental evidence from studies of human donors with AMD supports the emerging hypothesis that defects in RPE mitochondria drive AMD pathology. These studies, using different experimental methods, have shown disrupted RPE mitochondrial architecture and decreased mitochondrial number and mass, altered content of multiple mitochondrial proteins, increased mitochondrial DNA damage that correlates with disease severity, and defects in bioenergetics for primary RPE cultures from AMD donors. Herein, we discuss a model of metabolic uncoupling that alters bioenergetics in the diseased retina and drives AMD pathology. These data provide the rationale for targeting the mitochondria in the RPE as the most efficacious intervention strategy if administered early, before vision loss and cell death.