Abstract
Purpose :
Retinal markers of Alzheimer’s disease (AD) related pathology may be visible in the eye. The retina is an extension of the brain and is the only organ which can be imaged non-invasively. Cost-effective imaging of AD markers in the retina could be a revolutionary screening technique and provide an effective methodology for monitoring future treatment trials. People with Down’s syndrome have a high-prevalence of early onset AD and overproduction of amyloid-beta (Aβ).
Methods :
This project used optical coherence tomography (OCT) retinal imaging to measure retinal thickness and magnetic resonance imaging (MRI) to measure cortical thickness in 18 adults with DS between the ages of 35 and 55 years. Participants also underwent positron emission tomography (PET) neuroimaging using Pittsburgh compound [11C]-PIB to quantify Aβ in the brain. Six of the 18 participants were found to have positive PIB Aβ binding. Associations between cortical and retinal thickness are evaluated between PIB groups and retinal thickness between groups compared to age-matched healthy controls.
Results :
Results from this study show that adults with DS have significantly thicker retinal measures than age-matched healthy controls. Adults with DS with positive PIB binding in the brain (PIB positive) showed trends towards thinner retina than those with negative PIB binding (PIB negative; PIB negative inner retinal layers mean thickness= 242.6µ, PIB positive group mean= 232.33). The PIB negative group had significantly thicker retina in comparison to age-matched controls (p< .001) whereas retinal thicknesses were not significantly different between the PIB positive group and age-matched controls. Additionally, the relationship between cortical thickness and retinal thickness measures changed between the groups. Large positive correlations were found in the PIB negative group, whereas the PIB positive group showed a trend towards a negative correlation between retinal and cortical thickness.
Conclusions :
Evidence of thicker retina in adults with DS may be reflective of Aβ and related AD pathology responses. This study has shown some evidence of increased retinal thickening in people with DS in relation to age. Longitudinal assessments of retinal thickness in people with DS are planned, along with studies to assess rates of apoptosis and Aβ deposits in the retina.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.