Analysis of amyloid deposits in the retina and implications for use as a biomarker of Alzheimer’s Disease

Background In humans and the naturally occurring canine model of Alzheimer’s disease (AD), we others observe amyloid deposits in retina en face. We have previously shown that detecting number with polarised light, using wide field, dye free retinal imaging, can predict degree severity AD pathology brain. But some who take thin, transverse sections find while do not. Here, report surface area human AD. Method Formalin-fixed retinas from 29 individuals a moderate to high likelihood (with comorbidities excluded) 20 canines were flat-mounted imaged florescence polarized light (Fig 1). The full was for 24 16 retinas. For 4 canines, in-vivo blue fluorescent images collected before after injection an dye, CRANAD-28. Deposits visible only counted. Fluorescence polarization compared post-mortem Amyloid segmented custom methods. total then divided by imaged. Result brain pathology, covered on average 0.01% correlated 2). vivo 3), 0.29% 4). one ex retina, positive had concurrence 93% (0.14%) larger than same polarimetry (0.08%) (Fig. 5). Conclusion These findings our previous almost constant density across should guide imaging as biomarker Across all retinas, less 0.6% surface. Careful, extensive sampling is needed. additional potential severity.