Bridging Animal and Human Models of Exercise-induced Visual Rehabilitation

Not Applicable

Active, not recruiting

Conditions: Vision Disorders

Interventions: Behavioral: Balance exercise
Behavioral: Aerobic exercise

Registration Number: NCT02911805

Lead Sponsor: VA Office of Research and Development

Brief Summary: This study will determine whether blood biomarker changes predict sight-saving benefits of exercise.

Detailed Description: 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.

Recruitment & Eligibility

Status: ACTIVE_NOT_RECRUITING

Sex: All

Target Recruitment: 14

Inclusion Criteria

English speaking
Aged 18 to 89
Sedentary as defined by < 120 min/week of aerobic exercise over prior 3 months
Non-demented (MMSE 24)

Exclusion Criteria

Severe diabetes requiring insulin
Cognitive-executive function deficit (MoCA < 26)

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Balance Training	Balance exercise	Group balance training 3 times a week
Aerobic Exercise	Aerobic exercise	Exercise 3 times a week

Primary Outcome Measures

Name	Time	Method
Visual Acuity - Mean Acuity Change	12 weeks	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.

Secondary Outcome Measures

Name	Time	Method
Contrast Sensitivity	12 weeks	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.
Concentration of Brain-Derived Neurotrophic Factor (BDNF) in Serum.	12 weeks	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.