Putting Regeneration into Regenerative Medicine

The prevalence of blinding diseases such as agerelated macular degeneration (AMD), glaucoma and diabetic retinopathy have significantly increased in the United States over the last decade.1 In response to the higher incidence of retinal degenerative diseases, the National Eye Institute (NEI) of the US National Institutes of Health (NIH) has recently proposed the audacious goal of regenerating neurons and neural connections in the eye and visual system.2 To date, regenerative medicine has to a large extent focused on determining how to reprogram stem cells into retinal neurons that can be used to restore vision. Recent surprising findings, however, suggest that mammals may possess limited in vivo regenerative potential. The challenge now lies in understanding why the retina in other vertebrates regenerates, while mammals lack this ability. In this review, we summarize current knowledge on endogenous mechanisms of regeneration in frogs and how these findings might provide essential information to stimulate regeneration in the human retina.