Abstract
Noninvasive detection of amyloid-β (Aβ) deposits in the brain would be beneficial for an early and presymptomatic diagnosis of Alzheimer's disease (AD). We developed THK-265 as a candidate near-infrared fluorescence (NIRF) probe for the in vivo detection of amyloid deposits in the brain. The maximal emission wavelength of THK-265 was greater than 650nm and it showed high quantum yield and molar absorption coefficients. A fluorescence binding assay showed its high binding affinity to Aβ fibrils (Kd = 97 nM). THK-265 clearly stained amyloid plaques in AD neocortical brain sections and showed a moderate log p value (1.8). After intravenous administration of THK-265 in amyloid-β protein precursor (AβPP) transgenic mice, amyloid deposits in the brain were clearly labeled with THK-265. Furthermore, in vivo NIRF imaging demonstrated significantly higher fluorescence intensity in the brains of AβPP transgenic mice than in those of wild-type mice. As THK-265 showed profound hyperchromic effect upon binding to Aβ fibrils, good discrimination between AβPP transgenic and wild-type mice was demonstrated even early after THK-265 administration. Furthermore, the fluorescence intensity of THK-265 correlated with amyloid plaque burden in the brains of AβPP transgenic mice. These findings strongly support the usefulness of THK-265 as an NIRF imaging probe for the noninvasive measurement of brain amyloid load.
Original language | English |
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Pages (from-to) | 37-48 |
Number of pages | 12 |
Journal | Journal of Alzheimer's Disease |
Volume | 23 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2011 |
Keywords
- Alzheimer's disease
- amyloid
- amyloid-β protein
- fluorescence
- molecular imaging
ASJC Scopus subject areas
- Neuroscience(all)
- Clinical Psychology
- Geriatrics and Gerontology
- Psychiatry and Mental health