Identification of Retinal Amyloid-Beta in Ex Vivo Human Glaucoma Eyes Using a Novel Ocular Tracer.

PURPOSE: To characterize the presence of amyloid-beta (Aβ) in human glaucoma retina and to test the identification of retinal Aβ using a novel fluorescent Aβ-binding small molecule (AMDX-2011).

METHODS

Postmortem human eyes with (n=4) and without (n=4) glaucoma were acquired from an eye bank. Retinas were dissected, flat-mounted, and fixed. Using the flat mounts, immunofluorescence was performed against Aβ, AMDX-2011 staining was conducted, and images were acquired using fluorescence microscopy.

RESULTS

Fluorescence microscopy demonstrated the presence of an Aβ signal that colocalized with AMDX-2011 staining in the glaucoma retina. Colabeled puncta appeared in all quadrants of the retina, including the retina temporal to the optic nerve. The puncta were mainly located within the inner layers of the retina. Glaucoma retinas had more colabeled puncta than control retinas in all locations ( P =0.002-0.02). Colabeled puncta were also larger in the superior quadrant of glaucoma compared with control retinas ( P =0.02).

CONCLUSIONS

Aβ was detected in human glaucomatous retina, and its distribution was mapped. AMDX-2011 identification of Aβ may lead to future diagnostic tests aimed at detecting Aβ in glaucoma patients.