Bridging Animal and Human Models of Exercise-induced Visual Rehabilitation

Investigators of the Atlanta VA Center for Visual and Neurocognitive Rehabilitation (CVNR) find a very high prevalence of blinding diseases in the aging Veteran population. There are few treatments for the disorders that threaten our Veterans' eyesight. The work proposed here is the first step in determining whether exercise can be used by aging Veterans as an inexpensive and self-controlled therapy for vision loss. In order to translate exercise therapy for vision into the clinic, the investigators need to identify biomarkers that can be used to predict visual benefits. Though human and animal studies show that aerobic exercise is beneficial to specific central and peripheral nervous system functions, effects on the retina and vision were unknown until the investigators recently discovered that treadmill exercise directly protects retinal neurons in mice undergoing light-induced retinal degeneration (LIRD). The investigators found that exercise increased levels of brain-derived neurotrophic factor (BDNF) a blood protein in the blood, brain and eyes, whereas treatment of mice with a BDNF inhibitor prevented the protective effects of exercise. For this study, the investigators will assess visual outcomes and serum biomarkers (e.g, BDNF) in 60 subjects age 18-89 before, during, and after aerobic exercise. Subjects currently enrolled in a 12-week study (under Institutional Review Board (IRB) 56726) examining the effects of aerobic exercise on cognition will have visual testing (ERG, visual acuity, contrast sensitivity, and OCT) and blood collection prior to, during and after the standardized 12-week aerobic exercise regimen to determine whether circulating biomarker levels and visual outcomes are correlated and whether biomarker levels are altered as predicted in animal studies. This study will determine whether biomarker changes predict sight-saving benefits of exercise. As opposed to surgery or pharmacological treatments, exercise programs provide a means for Veterans to exert some control over their visual disease progression and will increase their overall health.