Detection of TTR Amyloid in the Conjunctiva Using a Novel Fluorescent Ocular Tracer.
Julie Pilotte, Alex S Huang, Sami Khoury, Xiaowei Zhang, Ali Tafreshi, Peter Vanderklish, Stella T Sarraf, Jose S Pulido, Tatyana Milman
Author Information
Julie Pilotte: Amydis, Inc., La Jolla, CA, USA.
Alex S Huang: Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.
Sami Khoury: Amydis, Inc., La Jolla, CA, USA.
Xiaowei Zhang: Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.
Ali Tafreshi: Amydis, Inc., La Jolla, CA, USA.
Peter Vanderklish: Amydis, Inc., La Jolla, CA, USA.
Stella T Sarraf: Amydis, Inc., La Jolla, CA, USA.
Jose S Pulido: Vickie and Jack Farber Vision Research Center and MidAtlantic Retina Service, Wills Eye Hospital, Philadelphia, PA, USA.
Tatyana Milman: Vickie and Jack Farber Vision Research Center and MidAtlantic Retina Service, Wills Eye Hospital, Philadelphia, PA, USA.
Background: Transthyretin amyloidosis (ATTR) is a significant cause of cardiomyopathy and other morbidities in the elderly and Black Americans. ATTR can be treated with new disease-modifying therapies, but large shortfalls exist in its diagnosis. The objective of this study was to test whether TTR amyloid can be detected and imaged in the conjunctiva using a novel small-molecule fluorescent ocular tracer, with the implication that ATTR might be diagnosable by a simple eye examination. Methods: Three approaches were used in this study. First, AMDX-9101 was incubated with in vitro aggregated TTR protein, and changes in its excitation and emission spectra were quantified. Second, a cadaver eye from a patient with familial amyloid polyneuropathy type II TTR mutation and a vitrectomy sample from an hATTR patient were incubated with AMDX-9101 and counterstained with Congo Red and antibodies to TTR to determine whether AMDX-9101 labels disease-related TTR amyloid deposits in human conjunctiva and eye. Last, imaging of in vitro aggregated TTR amyloid labeled with AMDX-9101 was tested in a porcine ex vivo model, using a widely available clinical ophthalmic imaging device. Results: AMDX-9101 hyper-fluoresced in the presence of TTR amyloid in vitro, labeled TTR amyloid deposits in postmortem human conjunctiva and other ocular tissues and could be detected under the conjunctiva of a porcine eye using commercially available ophthalmic imaging equipment. Conclusions: AMDX-9101 enabled detection of TTR amyloid in the conjunctiva, and the fluorescent binding signal can be visualized using commercially available ophthalmic imaging equipment. Translational Relevance: AMDX-9101 detection of TTR amyloid may provide a potential new and noninvasive test for ATTR that could lead to earlier ATTR diagnosis, as well as facilitate development of new therapeutics.
References
Am J Pathol. 1984 Dec;117(3):391-9
[PMID: 6507586]
