Assessing THK523 selectivity for tau deposits in Alzheimer's disease and non-Alzheimer's disease tauopathies.

Abstract

INTRODUCTION:

The introduction of tau imaging agents such as (18)F-THK523 offers new hope for the in vivo assessment of tau deposition in tauopathies such as Alzheimer's disease (AD), where preliminary (18)F-THK523-PET studies have demonstrated significantly higher cortical retention of (18)F-THK523 in AD compared to age-matched healthy individuals. In addition to AD, tau imaging with PET may also be of value in assessing non-AD tauopathies, such as corticobasal degeneration (CBD), progressive supranuclear palsy (PSP) and Pick's disease (PiD).

METHODS:

To further investigate the ability of THK523 to recognize tau lesions, we undertook immunohistochemical and fluorescence studies in serial brain sections taken from individuals with AD (n = 3), CBD (n = 2), PSP (n = 1), PiD (n = 2) and Parkinson's disease (PD; n = 2). In addition to the neuropathological analysis, one PSP patient had undergone a (18)F-THK523 PET scan 5 months before death.

RESULTS:

Although THK523 labelled tau-containing lesions such as neurofibrillary tangles and neuropil threads in the hippocampus and frontal regions of AD brains, it failed to label tau-containing lesions in non-AD tauopathies. Furthermore, though THK523 faintly labelled dense-cored amyloid-β plaques in the AD frontal cortex, it failed to label α-synuclein-containing Lewy bodies in PD brain sections.

CONCLUSION:

The results of this study suggest that (18)F-THK523 selectively binds to paired helical filament tau in AD brains but does not bind to tau lesions in non-AD tauopathies, or to α-synuclein in PD brains.

• Authors: Michelle T Fodero-Tavoletti, Shozo Furumoto, Leanne Taylor, Catriona A McLean, Rachel S Mulligan, Ian Birchall, Ryuichi Harada, Colin L Masters, Kazuhiko Yanai, Yukitsuka Kudo, Christopher C Rowe, Nobuyuki Okamura, Victor L Villemagne
• Journal: Alzheimer's research & therapy (Alzheimers Res Ther) Vol. 6 Issue 1 Pg. 11 ( 2014) ISSN: 1758-9193 [Print] England
• PMID: 24572336 (Publication Type: Journal Article)