1. An autoradiographic evaluation of AV-1451 Tau PET in dementia.
- Author
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Lowe VJ, Curran G, Fang P, Liesinger AM, Josephs KA, Parisi JE, Kantarci K, Boeve BF, Pandey MK, Bruinsma T, Knopman DS, Jones DT, Petrucelli L, Cook CN, Graff-Radford NR, Dickson DW, Petersen RC, Jack CR Jr, and Murray ME
- Subjects
- Aged, Aged, 80 and over, Brain diagnostic imaging, Brain metabolism, Brain pathology, DNA-Binding Proteins metabolism, Dementia metabolism, Dementia pathology, Female, Humans, Male, Middle Aged, Neurodegenerative Diseases diagnostic imaging, Neurodegenerative Diseases metabolism, Neurodegenerative Diseases pathology, Protein Isoforms, Autoradiography, Carbolines chemical synthesis, Dementia diagnostic imaging, Positron-Emission Tomography, Radiopharmaceuticals chemical synthesis, tau Proteins metabolism
- Abstract
Background: It is essential to determine the specificity of AV-1451 PET for tau in brain imaging by using pathological comparisons. We performed autoradiography in autopsy-confirmed Alzheimer disease and other neurodegenerative disorders to evaluate the specificity of AV-1451 binding for tau aggregates., Methods: Tissue samples were selected that had a variety of dementia-related neuropathologies including Alzheimer disease, primary age-related tauopathy, tangle predominant dementia, non-Alzheimer disease tauopathies, frontotemporal dementia, parkinsonism, Lewy body disease and multiple system atrophy (n = 38). Brain tissue sections were stained for tau, TAR DNA-binding protein-43, and α-synuclein and compared to AV-1451 autoradiography on adjacent sections., Results: AV-1451 preferentially localized to neurofibrillary tangles, with less binding to areas enriched in neuritic pathology and less mature tau. The strength of AV-1451 binding with respect to tau isoforms in various neurodegenerative disorders was: 3R + 4R tau (e.g., AD) > 3R tau (e.g., Pick disease) or 4R tau. Only minimal binding of AV-1451 to TAR DNA-binding protein-43 positive regions was detected. No binding of AV-1451 to α-synuclein was detected. "Off-target" binding was seen in vessels, iron-associated regions, substantia nigra, calcifications in the choroid plexus, and leptomeningeal melanin., Conclusions: Reduced AV-1451 binding in neuritic pathology compared to neurofibrillary tangles suggests that the maturity of tau pathology may affect AV-1451 binding and suggests complexity in AV-1451 binding. Poor association of AV-1451 with tauopathies that have preferential accumulation of either 4R tau or 3R tau suggests limited clinical utility in detecting these pathologies. In contrast, for disorders associated with 3R + 4R tau, such as Alzheimer disease, AV-1451 binds tau avidly but does not completely reflect the early stage tau progression suggested by Braak neurofibrillary tangle staging. AV-1451 binding to TAR DNA-binding protein-43 or TAR DNA-binding protein-43 positive regions can be weakly positive. Clinical use of AV-1451 will require a familiarity with distinct types of "off-target" binding.
- Published
- 2016
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