NAD+ and sirtuins in retinal degenerative diseases: A look at future therapies.

Retinal degenerative diseases are a major cause of morbidity in modern society because visual impairment significantly decreases the quality of life of patients. A significant challenge in treating retinal degenerative diseases is their genetic and phenotypic heterogeneity. However, despite this diversity, many of these diseases share a common endpoint involving death of light-sensitive photoreceptors. Identifying common pathogenic mechanisms that contribute to photoreceptor death in these diverse diseases may lead to a unifying therapy for multiple retinal diseases that would be highly innovative and address a great clinical need. Because the retina and photoreceptors, in particular, have immense metabolic and energetic requirements, many investigators have hypothesized that metabolic dysfunction may be a common link unifying various retinal degenerative diseases. Here, we discuss a new area of research examining the role of NAD+ and sirtuins in regulating retinal metabolism and in the pathogenesis of retinal degenerative diseases. Indeed, the results of numerous studies suggest that NAD+ intermediates or small molecules that modulate sirtuin function could enhance retinal metabolism, reduce photoreceptor death, and improve vision. Although further research is necessary to translate these findings to the bedside, they have strong potential to truly transform the standard of care for patients with retinal degenerative diseases.