This study will determine whether blood biomarker changes predict sight-saving benefits of exercise.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
14
Stationary bicycle ergometer @ 50-80% of maximal heart rate reserve for 20 minutes to 45 minutes
Instructor-led exercises done in a group setting for strengthening, balance, flexibility
Atlanta VA Medical and Rehab Center, Decatur, GA
Decatur, Georgia, United States
Visual Acuity - Mean Acuity Change
Early Treatment Diabetic Retinopathy Study (ETDRS) chart was used. Higher scores mean a better outcome. The number of correct responses (e.g., number of letters read correctly) from a subject assessed prior to start of the first session of the the 12 week study was subtracted from the number of correct responses elicited at the end of the last session of the study. The means of these differences for each study group (Balance Training vs Aerobic Exercise) were compared by two-tailed t-test.
Time frame: 12 weeks
Contrast Sensitivity
Contrast sensitivity: The contrast sensitivity of the subjects will be measured with the Pelli-Robson Chart or Contrast Sensitivity Chart following the instructions provided with the chart. The two sides of the Pelli-Robson Chart have different letter sequences but are otherwise identical. The chart should be illuminated as uniformly as possible, so that the luminance of the white areas is between 80 and 120 cd/ m2 with no glare. The patient should sit directly in front of the chart at a distance of 1 meter (use the same 1 meter string as for visual acuity testing to measure the eye-to-chart distance). Subjects should be prevented from seeing the chart until the contrast sensitivity testing actually begins. Subjects should wear their best distance correction.
Time frame: 12 weeks
Concentration of Brain-Derived Neurotrophic Factor (BDNF) in Serum.
Blood will be drawn prior to and after exercise sessions. From this, serum levels of brain derived neurotrophic factor (BDNF) will measured by immunoenzymatic assay.
Time frame: 12 weeks
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