Category: Parkinsonism, Atypical: PSP, CBD
Objective: The aim of this single center study was to analyse the potential of 18F-GE-180 TSPO PET as a biomarker in 4R-tauopathies.
Background: The pathological entities Progressive Supranuclear Palsy (PSP) and Corticobasal Degeneration (CBD) are caused by four-repeat (4R) tau isoforms with heterogeneous clinical presentation. The most common condition of 4R tau aggregation is Richardson’s Syndrome (RS). Corticobasal Syndrome (CBS) is also most frequently caused by 4R-tauopathies, less frequently by the 3-repeat/4-repeat tauopathy Alzheimer’s disease (AD). Ante-mortem diagnosis of the underlying pathology is challenging and in vivo biomarkers for potential therapeutic targets still need to be established. Microglia have been shown to be activated in AD and 4R-tauopathies. TSPO PET (18F-GE-180) targets the 18kDa translocator protein expressed in activated microglia.
Method: 18F-GE-180 PET was performed in 14 patients with probable PSP-RS, 31 patients with CBS, fulfilling the Movement Disorders Society and/or Armstrong Clinical Research criteria, and 14 healthy controls. Amyloid-PET and cerebral spinal fluid served for assessment of β-amyloid status to exclude underlying AD pathology in the CBS cohort. The CBS group is embedded in the interdisciplinary AD study “Activity of Cerebral Networks, Amyloid and Microglia in Aging and AD”. Volume-of-interest based quantification of standardized-uptake-values was conducted in 21 disease related target regions.
Results: The RS and CBS group did not show significant differences in age (RS: 68.8±8.0, CBS: 68.2±8.9), disease duration (RS: 36.7±33.8, CBS: 33.0±24.0) and MoCA (RS: 22.2±7.8, CBS: 22.6±4.7). Significantly elevated TSPO expression was observed in RS versus healthy controls predominantly in basal ganglia and the midbrain. CBS patients showed additional elevated tracer binding in frontal cortical regions.
Conclusion: Our data indicate that 18F-GE-180 PET is a potential biomarker to detect microglial activation in various cortical and subcortical brain regions in 4R-tauopathies, fitting to predilection sites of the phenotype. TSPO-PET may serve as a biomarker for immunmodulatory therapies of 4R-tauopathies.
To cite this abstract in AMA style:C. Palleis, J. Sauerbeck, L. Beyer, S. Harris, J. Schmitt, A. Finze, A. Nitschmann, G. Biechele, K. Boetzel, A. Danek, B. Rauchmann, M. Unterrainer, N. Albert, R. Rupprecht, P. Bartenstein, R. Perneczky, C. Haass, J. Levin, G. Hoeglinger, M. Brendel. 18kDa Translocator Protein PET in 4-Repeat Tauopathies – A Cross-Sectional Single Center Study [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/18kda-translocator-protein-pet-in-4-repeat-tauopathies-a-cross-sectional-single-center-study/. Accessed September 25, 2023.
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MDS Abstracts - https://www.mdsabstracts.org/abstract/18kda-translocator-protein-pet-in-4-repeat-tauopathies-a-cross-sectional-single-center-study/