Three-Dimensional β-Amyloid Burden Correlation Between the Eye and Brain in Alzheimer's Disease Mice Using Light-Sheet Fluorescence Microscopy

초록

Purpose: Recent studies have highlighted the significance of peripheral beta-amyloid (A beta) deposition, identifying the eye as a potential early detection site for Alzheimer's disease (AD). However, previous two-dimensional AD ocular studies have been unable to establish a clear correlation between the three-dimensional A beta accumulation in the entire eyeball and brain while preserving structural integrity. This study employed a combined brain amyloid positron emission tomography/magnetic resonance (PET/MR) and light-sheet fluorescence microscopy (LSFM) platform to assess whether the three-dimensionally measured A beta burden in the eyeball correlates with that in the brain. Methods: Thirteen eyeballs (6 AD, 7 control) and 17 brains (10 AD, 7 control) were collected from ten 44-week-old 5xFAD and seven control mice. The samples underwent tissue clearing and staining with thioflavin S (A beta), anti-CD11b (microglia), and anti-ACSA-2 (astrocytes) for LSFM imaging and quantified via 3D surface volume. Standardized uptake value ratios from [F-18]Flutemetamol PET/MR were also calculated. Results: AD eyeballs presented significantly greater plaque-like surface volumes (median, 51,091,002 mu m(3) [interquartile range, 38,488,272-64,869,828]) than controls (229,293 mu m(3) [115,863-311,5320]; P = 0.001). AD brains exhibited higher [F-18]Flutemetamol uptake and greater plaque-like surface volumes (898,634,368 mu m(3) [556,263,488-1,105,326,720]) than controls (33,320,178 mu m(3) [26,842,538-62,716,956]; P < 0.001). A strong positive correlation was observed between the plaque-like surface volumes in the brain and that in the eyeball (r = 0.810, P = 0.001). No significant correlations were found in other morphologic parameters. Conclusions: Our observation of a strong correlation between the three-dimensional A beta burden in the whole eyeball and brain advances our understanding of the systemic nature of A beta pathology and suggests ocular A beta as a potential independent predictor of brain A beta burden.

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