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Lee E Goldstein, Susanne Wilke, Dennis Nilan, Ira Goodman, Carl Sadowsky; A PRE-Pivotal Study: β-Amyloid Detection in the Lens in Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD) - Correlation with Amyloid-PET Brain Scanning. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2092.
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There is a great need for non-invasive diagnostic tools to screen, diagnose, and track patients with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD). In AD, the brain accumulates β-amyloid (Aβ) as plaque detectable by amyloid-PET brain scans. Aβ accumulates in lenses from AD patients but not patients with other neurodegenerative diseases (Goldstein et al., 2003). Identical Aβ lens pathology has been identified in patients with Down syndrome (Moncaster et al., 2010), a chromosomal disorder in which Aβ brain pathology is an invariant feature. We developed an non-invasive drug-device eye scanner to evaluate lens Aβ. The Sapphire II platform (Cognoptix) combines a topically-applied Aβ-binding fluorescent ligand with a molecular spectroscopy ophthalmoscope that distinguishes normal subjects from those with probable AD (Kerbage et al., 2014). Sapphire II scan shows greater sensitivity and specificity than amyloid-PET scans vs clinical diagnosis for AD. This study evaluated Sapphire II screening vs amyloid-PET scans in earlier MCI and mild AD subjects.
48 participants: 28 MCI, 16 Mild AD patients, 4 Normal Control subjects were studied. All MCI and AD subjects underwent cognitive testing and amyloid-PET scans. The Sapphire II system couples a medical imaging ointment that contains the Aβ-binding fluorescent ligand, Aftobetin, and a Fluorescent Laser Eye Scanning (FLES) device that detects a spectral shifted fluorescent signature signal of bound Aftobetin-Aβ complexes in the lens. Each scan takes <1 sec and multiple readings can be obtained in a single sitting.
43 subjects have been evaluated to date. No serious adverse events were reported. There was no instance where Sapphire II was negative and amyloid-PET scans were positive, indicating of a high degree of diagnostic specificity. Of the 39 Sapphire II positive subjects, positive amyloid-PET scans were noted in 26. Evaluation of individual PET scans and cognitive testing suggests that Sapphire II is more sensitive than amyloid-PET scans compared to clinical criteria.
Sapphire II is a convenient, inexpensive, rapid non-invasive screening tool that detects AD-related Aβ accumulation in the lens of subjects with MCI and mild AD. We are exploring the utility of Sapphire II in patients with early prodromal asymptomatic AD ("preclinical AD").
This is a 2021 ARVO Annual Meeting abstract.
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