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Mohammadi Z, Alizadeh H, Marton J, Cumming P. The Sensitivity of Tau Tracers for the Discrimination of Alzheimer's Disease Patients and Healthy Controls by PET. Biomolecules 2023; 13:290. [PMID: 36830659 PMCID: PMC9953528 DOI: 10.3390/biom13020290] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/12/2023] [Accepted: 01/25/2023] [Indexed: 02/09/2023] Open
Abstract
Hyperphosphorylated tau aggregates, also known as neurofibrillary tangles, are a hallmark neuropathological feature of Alzheimer's disease (AD). Molecular imaging of tau by positron emission tomography (PET) began with the development of [18F]FDDNP, an amyloid β tracer with off-target binding to tau, which obtained regional specificity through the differing distributions of amyloid β and tau in AD brains. A concerted search for more selective and affine tau PET tracers yielded compounds belonging to at least eight structural categories; 18F-flortaucipir, known variously as [18F]-T807, AV-1451, and Tauvid®, emerged as the first tau tracer approved by the American Food and Drug Administration. The various tau tracers differ concerning their selectivity over amyloid β, off-target binding at sites such as monoamine oxidase and neuromelanin, and degree of uptake in white matter. While there have been many reviews of molecular imaging of tau in AD and other conditions, there has been no systematic comparison of the fitness of the various tracers for discriminating between AD patient and healthy control (HC) groups. In this narrative review, we endeavored to compare the binding properties of the various tau tracers in vitro and the effect size (Cohen's d) for the contrast by PET between AD patients and age-matched HC groups. The available tracers all gave good discrimination, with Cohen's d generally in the range of two-three in culprit brain regions. Overall, Cohen's d was higher for AD patient groups with more severe illness. Second-generation tracers, while superior concerning off-target binding, do not have conspicuously higher sensitivity for the discrimination of AD and HC groups. We suppose that available pharmacophores may have converged on a maximal affinity for tau fibrils, which may limit the specific signal imparted in PET studies.
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Affiliation(s)
- Zohreh Mohammadi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5166/15731, Iran
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz 5166/15731, Iran
| | - Hadi Alizadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5166/15731, Iran
| | - János Marton
- ABX Advanced Biochemical Compounds Biomedizinische Forschungsreagenzien GmbH, Heinrich-Glaeser-Straße 10-14, D-01454 Radeberg, Germany
| | - Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, Freiburgstraße 18, CH-3010 Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD 4059, Australia
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Xu J, Xia Y, Meng M, Liu F, Che P, Zhang Y, Wang Y, Cai L, Qin W, Zhang N. Clinical features and biomarkers of semantic variant primary progressive aphasia with MAPT mutation. Alzheimers Res Ther 2023; 15:21. [PMID: 36707904 PMCID: PMC9881263 DOI: 10.1186/s13195-023-01176-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 01/23/2023] [Indexed: 01/28/2023]
Abstract
BACKGROUND Semantic variant primary progressive aphasia (svPPA) is generally sporadic, with very few reports of tau pathology caused by MAPT mutations. METHODS A 64-year-old man was diagnosed with svPPA with MAPT P301L mutation. Clinical information, cognitive and language functions, multimodal magnetic resonance imaging (MRI), blood biomarkers, fluorodeoxyglucose (FDG) imaging and tau positron emission tomography (PET) were obtained. RESULTS Semantic memory impairment was the earliest and most prominent symptom in this family. Tau accumulation and hypometabolism were observed prior to brain atrophy in mutation carriers. Plasma NfL and GFAP concentrations were elevated in the two svPPA patients. Some relative decreases and some relative increases in regional cerebral blood flow (CBF) as measured by arterial spin labelling (ASL) were observed in mutation carriers compared to noncarriers. CONCLUSIONS This study describes a large svPPA-affected family with the MAPT P301L mutation and provides an ideal model for inferring underlying pathology and pathophysiological processes in svPPA caused by tauopathies.
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Affiliation(s)
- Jing Xu
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heing District, Tianjin, 300052 China
| | - Yanmin Xia
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heing District, Tianjin, 300052 China ,grid.459324.dDepartment of Neurology, Affiliated Hospital of Hebei University, Baoding, 071000 Hebei China
| | - Meng Meng
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Medical University General Hospital Airport Site, Tianjin, China
| | - Fang Liu
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heing District, Tianjin, 300052 China
| | - Ping Che
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heing District, Tianjin, 300052 China
| | - Yanxin Zhang
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heing District, Tianjin, 300052 China
| | - Ying Wang
- grid.412645.00000 0004 1757 9434Department of PET-CT Diagnostic, Tianjin Medical University General Hospital, Tianjin, 300052 China
| | - Li Cai
- grid.412645.00000 0004 1757 9434Department of PET-CT Diagnostic, Tianjin Medical University General Hospital, Tianjin, 300052 China
| | - Wen Qin
- grid.412645.00000 0004 1757 9434Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Nan Zhang
- grid.412645.00000 0004 1757 9434Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heing District, Tianjin, 300052 China
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Fu L, Zhang J, Zhou K, Zhang X, Xie H, Zhu M, Cui M, Wang R. In vivo imaging of tau deposition in Alzheimer’s disease using both [18F]-THK5317 and [18F]-S16: A pilot human study. Front Aging Neurosci 2022; 14:994750. [PMID: 36092808 PMCID: PMC9459225 DOI: 10.3389/fnagi.2022.994750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
Objective To evaluate the effectiveness of a new tracer (S)-1-(4-(6-(dimethylamino)quinoxalin-2-yl)phenoxy)-3-fluoropropan-2-ol ([18F]-S16), in distinguishing patients with AD from HCs. Methods Paired [18F]-S16 and [18F]-THK5317 scans were acquired in five patients with AD, six HCs, one subject with a semantic variant of primary progressive aphasia (sv-PPA) and one subject with probable progressive supranuclear palsy (PSP). Dynamic PET scanning was performed over 90 min after injection of the tracers. Standardized uptake values (SUV) and cortical-to-cerebellum standardized uptake value ratios (SUVRs) were used for tau deposition semi-quantization. A voxel-based analysis was employed to assess the uptake difference between populations. Results [18F]-S16 exhibited excellent blood-brain-barrier penetration. AD patients showed increased cortical [18F]-THK5317 and [18F]-S16 binding. Compared to HCs, AD patients showed significantly increased cortical [18F]-S16 uptake in the bilateral occipital cortex, posterior cingulated cortex/precuneus, and lateral frontal cortex. Notable [18F]-S16 uptake was observed in the basal ganglia and brainstem compared to the neocortex. A substantial [18F]-S16 signal was detected in the basal ganglia and midbrain in a patient with probable PSP and in the bilateral anterior temporal cortex in a sv-PPA patient. Conclusion [18F]-S16 might be of help to detect tau protein in vivo.
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Affiliation(s)
- Liping Fu
- Department of Nuclear Medicine, China-Japan Friendship Hospital, Beijing, China
- *Correspondence: Liping Fu,
| | - Jinming Zhang
- Department of Nuclear Medicine, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Kaixiang Zhou
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Xiaojun Zhang
- Department of Nuclear Medicine, First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Hengge Xie
- Department of Neurology, The Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Mingwei Zhu
- Department of Neurology, The Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Mengchao Cui
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Ruimin Wang
- Department of Nuclear Medicine, First Medical Center, Chinese PLA General Hospital, Beijing, China
- Ruimin Wang,
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Biomarker Candidates for Alzheimer’s Disease Unraveled through In Silico Differential Gene Expression Analysis. Diagnostics (Basel) 2022; 12:diagnostics12051165. [PMID: 35626321 PMCID: PMC9139748 DOI: 10.3390/diagnostics12051165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 01/27/2023] Open
Abstract
Alzheimer’s disease (AD) is neurodegeneration that accounts for 60–70% of dementia cases. Symptoms begin with mild memory difficulties and evolve towards cognitive impairment. The underlying risk factors remain primarily unclear for this heterogeneous disorder. Bioinformatics is a relevant research tool that allows for identifying several pathways related to AD. Open-access databases of RNA microarrays from the peripheral blood and brain of AD patients were analyzed after background correction and data normalization; the Limma package was used for differential expression analysis (DEA) through statistical R programming language. Data were corrected with the Benjamini and Hochberg approach, and genes with p-values equal to or less than 0.05 were considered to be significant. The direction of the change in gene expression was determined by its variation in the log2-fold change between healthy controls and patients. We performed the functional enrichment analysis of GO using goana and topGO-Limma. The functional enrichment analysis of DEGs showed upregulated (UR) pathways: behavior, nervous systems process, postsynapses, enzyme binding; downregulated (DR) were cellular component organization, RNA metabolic process, and signal transduction. Lastly, the intersection of DEGs in the three databases showed eight shared genes between brain and blood, with potential use as AD biomarkers for blood tests.
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