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Kouli A, Spindler LRB, Fryer TD, Hong YT, Malpetti M, Aigbirhio FI, White SR, Camacho M, O’Brien JT, Williams-Gray CH. Neuroinflammation is linked to dementia risk in Parkinson's disease. Brain 2024; 147:923-935. [PMID: 37757857 PMCID: PMC10907093 DOI: 10.1093/brain/awad322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/09/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
The development of dementia is a devastating aspect of Parkinson's disease (PD), affecting nearly half of patients within 10 years post-diagnosis. For effective therapies to prevent and slow progression to PD dementia (PDD), the key mechanisms that determine why some people with PD develop early dementia, while others remain cognitively unaffected, need to be understood. Neuroinflammation and tau protein accumulation have been demonstrated in post-mortem PD brains, and in many other neurodegenerative disorders leading to dementia. However, whether these processes mediate dementia risk early on in the PD disease course is not established. To this end, we used PET neuroimaging with 11C-PK11195 to index neuroinflammation and 18F-AV-1451 for misfolded tau in early PD patients, stratified according to dementia risk in our 'Neuroinflammation and Tau Accumulation in Parkinson's Disease Dementia' (NET-PDD) study. The NET-PDD study longitudinally assesses newly-diagnosed PD patients in two subgroups at low and high dementia risk (stratified based on pentagon copying, semantic fluency, MAPT genotype), with comparison to age- and sex-matched controls. Non-displaceable binding potential (BPND) in 43 brain regions (Hammers' parcellation) was compared between groups (pairwise t-tests), and associations between BPND of the tracers tested (linear-mixed-effect models). We hypothesized that people with higher dementia risk have greater inflammation and/or tau accumulation in advance of significant cognitive decline. We found significantly elevated neuroinflammation (11C-PK11195 BPND) in multiple subcortical and restricted cortical regions in the high dementia risk group compared with controls, while in the low-risk group this was limited to two cortical areas. The high dementia risk group also showed significantly greater neuroinflammation than the low-risk group concentrated on subcortical and basal ganglia regions. Neuroinflammation in most of these regions was associated with worse cognitive performance (Addenbrooke's Cognitive Examination-III score). Overall neuroinflammation burden also correlated with serum levels of pro-inflammatory cytokines. In contrast, increases in 18F-AV-1451 (tau) BPND in PD versus controls were restricted to subcortical regions where off-target binding is typically seen, with no relationship to cognition found. Whole-brain 18F-AV-1451 burden correlated with serum phosphorylated tau181 levels. Although there was minimal regional tau accumulation in PD, regional neuroinflammation and tau burden correlated in PD participants, with the strongest association in the high dementia risk group, suggesting possible co-localization of these pathologies. In conclusion, our findings suggest that significant regional neuroinflammation in early PD might underpin higher risk for PDD development, indicating neuroinflammation as a putative early modifiable aetiopathological disease factor to prevent or slow dementia development using immunomodulatory strategies.
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Affiliation(s)
- Antonina Kouli
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Lennart R B Spindler
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Tim D Fryer
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Young T Hong
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Maura Malpetti
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Franklin I Aigbirhio
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Simon R White
- Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge, CB2 0SL, UK
| | - Marta Camacho
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - John T O’Brien
- Department of Psychiatry, University of Cambridge, Cambridge, CB2 0SZ, UK
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2
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De Leiris N, Perret P, Lombardi C, Gözel B, Chierici S, Millet P, Debiossat M, Bacot S, Tournier BB, Chames P, Lenormand JL, Ghezzi C, Fagret D, Moulin M. A single-domain antibody for the detection of pathological Tau protein in the early stages of oligomerization. J Transl Med 2024; 22:163. [PMID: 38365700 PMCID: PMC10870657 DOI: 10.1186/s12967-024-04987-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/12/2024] [Indexed: 02/18/2024] Open
Abstract
BACKGROUND Soluble oligomeric forms of Tau protein have emerged as crucial players in the propagation of Tau pathology in Alzheimer's disease (AD). Our objective is to introduce a single-domain antibody (sdAb) named 2C5 as a novel radiotracer for the efficient detection and longitudinal monitoring of oligomeric Tau species in the human brain. METHODS The development and production of 2C5 involved llama immunization with the largest human Tau isoform oligomers of different maturation states. Subsequently, 2C5 underwent comprehensive in vitro characterization for affinity and specificity via Enzyme-Linked Immunosorbent Assay and immunohistochemistry on human brain slices. Technetium-99m was employed to radiolabel 2C5, followed by its administration to healthy mice for biodistribution analysis. RESULTS 2C5 exhibited robust binding affinity towards Tau oligomers (Kd = 6.280 nM ± 0.557) and to Tau fibers (Kd = 5.024 nM ± 0.453), with relatively weaker binding observed for native Tau protein (Kd = 1791 nM ± 8.714) and amyloid peptide (Kd > 10,000 nM). Remarkably, this SdAb facilitated immuno-histological labeling of pathological forms of Tau in neurons and neuritic plaques, yielding a high-contrast outcome in AD patients, closely mirroring the performance of reference antibodies AT8 and T22. Furthermore, 2C5 SdAb was successfully radiolabeled with 99mTc, preserving stability for up to 6 h post-radiolabeling (radiochemical purity > 93%). However, following intravenous injection into healthy mice, the predominant uptake occurred in kidneys, amounting to 115.32 ± 3.67, 97.70 ± 43.14 and 168.20 ± 34.52% of injected dose per gram (% ID/g) at 5, 10 and 45 min respectively. Conversely, brain uptake remained minimal at all measured time points, registering at 0.17 ± 0.03, 0.12 ± 0.07 and 0.02 ± 0.01% ID/g at 5, 10 and 45 min post-injection respectively. CONCLUSION 2C5 demonstrates excellent affinity and specificity for pathological Tau oligomers, particularly in their early stages of oligomerization. However, the current limitation of insufficient blood-brain barrier penetration necessitates further modifications before considering its application in nuclear medicine imaging for humans.
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Affiliation(s)
- Nicolas De Leiris
- University Grenoble Alpes, Clinique Universitaire de Médecine Nucléaire, INSERM, Centre Hospitalier Universitaire Grenoble Alpes, LRB, CS 10217, 38043, Grenoble CEDEX 9, France.
| | - Pascale Perret
- University Grenoble Alpes, INSERM, LRB, 38000, Grenoble, France
| | | | - Bülent Gözel
- University Grenoble Alpes, INSERM, LRB, 38000, Grenoble, France
| | - Sabine Chierici
- University Grenoble Alpes, CNRS, DCM, 38000, Grenoble, France
| | - Philippe Millet
- Division of Adult Psychiatry, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland
| | | | - Sandrine Bacot
- University Grenoble Alpes, INSERM, LRB, 38000, Grenoble, France
| | - Benjamin B Tournier
- Division of Adult Psychiatry, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland
| | - Patrick Chames
- Aix Marseille University, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Marseille, France
| | | | | | - Daniel Fagret
- University Grenoble Alpes, INSERM, LRB, 38000, Grenoble, France
| | - Marcelle Moulin
- University Grenoble Alpes, INSERM, LRB, 38000, Grenoble, France
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3
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Li J, Kumar A, Långström B, Nordberg A, Ågren H. Insight into the Binding of First- and Second-Generation PET Tracers to 4R and 3R/4R Tau Protofibrils. ACS Chem Neurosci 2023; 14:3528-3539. [PMID: 37639522 PMCID: PMC10515481 DOI: 10.1021/acschemneuro.3c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023] Open
Abstract
Primary supranuclear palsy (PSP) is a rare neurodegenerative disease that perturbs body movement, eye movement, and walking balance. Similar to Alzheimer's disease (AD), the abnormal aggregation of tau fibrils in the central neuronal and glial cells is a major hallmark of PSP disease. In this study, we use multiple approaches, including docking, molecular dynamics, and metadynamics simulations, to investigate the binding mechanism of 10 first- and second-generations of PET tracers for PSP tau and compare their binding in cortical basal degeneration (CBD) and AD tauopathies. Structure-activity relationships, binding preferences, the nature of ligand binding in terms of basic intermolecular interactions, the role of polar/charged residues, induced-fit mechanisms, grove closures, and folding patterns for the binding of these tracers in PSP, CBD, and AD tau fibrils are evaluated and discussed in detail in order to build a holistic picture of what is essential for the binding and also to rank the potency of the different tracers. For example, we found that the same tracer shows different binding preferences for the surface sites of tau fibrils that are intrinsically distinct in the folding patterns. Results from the metadynamics simulations predict that PMPBB3 and PBB3 exhibit the strongest binding free energies onto the Q276[I277]I278, Q351[S352]K353, and N368[K369]K370 sites of PSP than the other explored tracers, indicating a solid preference for vdW and cation-π interactions. Our results also reproduced known preferences of tracers, namely, that MK6240 binds better to AD tau than CBD tau and PSP tau and that CBD2115, PI2620, and PMPBB3 are 4R tau binders. These findings fill in the well-sought-after knowledge gap in terms of these tracers' potential binding mechanisms and will be important for the design of highly selective novel PET tracers for tauopathies.
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Affiliation(s)
- Junhao Li
- Department
of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Amit Kumar
- Department
of Neurobiology, Care Sciences and Society, Division of Clinical Geriatrics, Center for Alzheimer Research, Neo, 141 84 Stockholm, Sweden
| | - Bengt Långström
- Department
of Chemistry - BMC, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Agneta Nordberg
- Department
of Neurobiology, Care Sciences and Society, Division of Clinical Geriatrics, Center for Alzheimer Research, Neo, 141 84 Stockholm, Sweden
- Theme
Inflammation and Aging, Karolinska University
Hospital, S-141 86 Stockholm, Sweden
| | - Hans Ågren
- Department
of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
- College
of Chemistry and Chemical Engineering, Henan
University, Kaifeng, Henan 475004, P. R. China
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4
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Kim HY, Chia WK, Hsieh CJ, Guarino DS, Graham TJA, Lengyel-Zhand Z, Schneider M, Tomita C, Lougee MG, Kim HJ, Pagar VV, Lee H, Hou C, Garcia BA, Petersson EJ, O’Shea J, Kotzbauer PT, Mathis CA, Lee VMY, Luk KC, Mach RH. A Novel Brain PET Radiotracer for Imaging Alpha Synuclein Fibrils in Multiple System Atrophy. J Med Chem 2023; 66:12185-12202. [PMID: 37651366 PMCID: PMC10617560 DOI: 10.1021/acs.jmedchem.3c00779] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Abnormal α-synuclein (α-syn) aggregation characterizes α-synucleinopathies, including Parkinson's disease (PD) and multiple system atrophy (MSA). However, no suitable positron emission tomography (PET) radiotracer for imaging α-syn in PD and MSA exists currently. Our structure-activity relationship studies identified 4-methoxy-N-(4-(3-(pyridin-2-yl)-3,8-diazabicyclo[3.2.1]octan-8-yl)phenyl)benzamide (4i) as a PET radiotracer candidate for imaging α-syn. In vitro assays revealed high binding of 4i to recombinant α-syn fibrils (inhibition constant (Ki) = 6.1 nM) and low affinity for amyloid beta (Aβ) fibrils in Alzheimer's disease (AD) homogenates. However, [3H]4i also exhibited high specific binding to AD, progressive supranuclear palsy, and corticobasal degeneration tissues as well as PD and MSA tissues, suggesting notable affinity to tau. Nevertheless, the specific binding to pathologic α-syn aggregates in MSA post-mortem brain tissues was significantly higher than in PD tissues. This finding demonstrated the potential use of [11C]4i as a PET tracer for imaging α-syn in MSA patients. Nonhuman primate PET studies confirmed good brain uptake and rapid washout for [11C]4i.
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Affiliation(s)
- Ho Young Kim
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Wai Kit Chia
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Chia-Ju Hsieh
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Dinahlee Saturnino Guarino
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Thomas J. A. Graham
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Zsofia Lengyel-Zhand
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Mark Schneider
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Cosette Tomita
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Marshall G. Lougee
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6303, USA
| | - Vinayak V. Pagar
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Hsiaoju Lee
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Catherine Hou
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
| | - Benjamin A. Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6303, USA
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Jennifer O’Shea
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110-1010, USA
| | - Paul T. Kotzbauer
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110-1010, USA
| | - Chester A. Mathis
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Virginia M.-Y. Lee
- Center for Neurodegenerative Disease Research, Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104-2676, USA
| | - Kelvin C. Luk
- Center for Neurodegenerative Disease Research, Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104-2676, USA
| | - Robert H. Mach
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 S. 34th Street, Philadelphia, PA 19104-6323, USA
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5
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Matsuda H, Yamao T. Tau positron emission tomography in patients with cognitive impairment and suspected Alzheimer's disease. Fukushima J Med Sci 2023; 69:85-93. [PMID: 37302841 PMCID: PMC10480511 DOI: 10.5387/fms.2023-08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/10/2023] [Indexed: 06/13/2023] Open
Abstract
Alzheimer's disease (AD) is diagnosed by the presence of both amyloid β and tau proteins. Recent advances in molecular PET imaging have made it possible to assess the accumulation of these proteins in the living brain. PET ligands have been developed that bind to 3R/4R tau in AD, but not to 3R tau or 4R tau alone. Of the first-generation PET ligands, 18F-flortaucipir has recently been approved by the Food and Drug Administration. Several second-generation PET probes with less off-target binding have been developed and are being applied clinically. Visual interpretation of tau PET should be based on neuropathological neurofibrillary tangle staging instead of a simple positive or negative classification. Four visual read classifications have been proposed: "no uptake," "medial temporal lobe (MTL) only," "MTL AND," and "outside MTL." As an adjunct to visual interpretation, quantitative analysis has been proposed using MRI-based native space FreeSurfer parcellations. The standardized uptake value ratio of the target area is measured using the cerebellar gray matter as a reference region. In the near future, the Centiloid scale of tau PET is expected to be used as a harmonized value for standardizing each analytical method or PET ligand used, similar to amyloid PET.
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Affiliation(s)
- Hiroshi Matsuda
- Department of Biofunctional Imaging, Fukushima Medical University
| | - Tensho Yamao
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University
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6
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Graham TJA, Lindberg A, Tong J, Stehouwer JS, Vasdev N, Mach RH, Mathis CA. In Silico Discovery and Subsequent Characterization of Potent 4R-Tauopathy Positron Emission Tomography Radiotracers. J Med Chem 2023; 66:10628-10638. [PMID: 37487189 PMCID: PMC10424182 DOI: 10.1021/acs.jmedchem.3c00775] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Indexed: 07/26/2023]
Abstract
A chemical fingerprint search identified Z3777013540 (1-(5-(6-fluoro-1H-indol-2-yl)pyrimidin-2-yl)piperidin-4-ol; 1) as a potential 4R-tau binding ligand. Binding assays in post-mortem Alzheimer's disease (AD), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) brain with [3H]1 provided KD (nM) values in AD = 4.0, PSP = 5.1, and CBD = 4.5. In vivo positron emission tomography (PET) imaging in rats with [18F]1 demonstrated good brain penetration and rapid clearance from normal brain tissues. A subsequent molecular similarity search using 1 as the query revealed an additional promising compound, Z4169252340 (4-(5-(6-fluoro-1H-indol-2-yl)pyrimidin-2-yl)morpholine; 21). Binding assays with [3H]21 provided KD (nM) values in AD = 1.2, PSP = 1.6, and CBD = 1.7 and lower affinities for binding aggregated α-synuclein and amyloid-beta. PET imaging in rats with [18F]21 demonstrated a higher brain penetration than [18F]1 and rapid clearance from normal brain tissues. We anticipate that 1 and 21 will be useful for the identification of other potent novel 4R-tau radiotracers.
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Affiliation(s)
- Thomas J. A. Graham
- Department
of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United
States
| | - Anton Lindberg
- Azrieli
Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
| | - Junchao Tong
- Azrieli
Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
| | - Jeffrey S. Stehouwer
- Department
of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Neil Vasdev
- Azrieli
Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
- Department
of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada
| | - Robert H. Mach
- Department
of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United
States
| | - Chester A. Mathis
- Department
of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
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7
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Ozsahin I, Onakpojeruo EP, Uzun B, Uzun Ozsahin D, Butler TA. A Multi-Criteria Decision Aid Tool for Radiopharmaceutical Selection in Tau PET Imaging. Pharmaceutics 2023; 15:pharmaceutics15041304. [PMID: 37111789 PMCID: PMC10147085 DOI: 10.3390/pharmaceutics15041304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/09/2023] [Accepted: 04/19/2023] [Indexed: 04/29/2023] Open
Abstract
The accumulation of pathologically misfolded tau is a feature shared by a group of neurodegenerative disorders collectively referred to as tauopathies. Alzheimer's disease (AD) is the most prevalent of these tauopathies. Immunohistochemical evaluation allows neuropathologists to visualize paired-helical filaments (PHFs)-tau pathological lesions, but this is possible only after death and only shows tau in the portion of brain sampled. Positron emission tomography (PET) imaging allows both the quantitative and qualitative analysis of pathology over the whole brain of a living subject. The ability to detect and quantify tau pathology in vivo using PET can aid in the early diagnosis of AD, provide a way to monitor disease progression, and determine the effectiveness of therapeutic interventions aimed at reducing tau pathology. Several tau-specific PET radiotracers are now available for research purposes, and one is approved for clinical use. This study aims to analyze, compare, and rank currently available tau PET radiotracers using the fuzzy preference ranking organization method for enrichment of evaluations (PROMETHEE), which is a multi-criteria decision-making (MCDM) tool. The evaluation is based on relatively weighted criteria, such as specificity, target binding affinity, brain uptake, brain penetration, and rates of adverse reactions. Based on the selected criteria and assigned weights, this study shows that a second-generation tau tracer, [18F]RO-948, may be the most favorable. This flexible method can be extended and updated to include new tracers, additional criteria, and modified weights to help researchers and clinicians select the optimal tau PET tracer for specific purposes. Additional work is needed to confirm these results, including a systematic approach to defining and weighting criteria and clinical validation of tracers in different diseases and patient populations.
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Affiliation(s)
- Ilker Ozsahin
- Brain Health Imaging Institute, Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
- Operational Research Center in Healthcare, Near East University, Nicosia 99138, TRNC, Turkey
| | | | - Berna Uzun
- Operational Research Center in Healthcare, Near East University, Nicosia 99138, TRNC, Turkey
- Department of Statistics, Carlos III University of Madrid, Getafe, 28903 Madrid, Spain
| | - Dilber Uzun Ozsahin
- Operational Research Center in Healthcare, Near East University, Nicosia 99138, TRNC, Turkey
- Medical Diagnostic Imaging Department, College of Health Sciences & Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah P.O. Box 26666, United Arab Emirates
| | - Tracy A Butler
- Brain Health Imaging Institute, Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
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8
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Singh P, Singh D, Srivastava P, Mishra G, Tiwari AK. Evaluation of advanced, pathophysiologic new targets for imaging of CNS. Drug Dev Res 2023; 84:484-513. [PMID: 36779375 DOI: 10.1002/ddr.22040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/12/2022] [Accepted: 12/31/2022] [Indexed: 02/14/2023]
Abstract
The inadequate information about the in vivo pathological, physiological, and neurological impairments, as well as the absence of in vivo tools for assessing brain penetrance and the efficiency of newly designed drugs, has hampered the development of new techniques for the treatment for variety of new central nervous system (CNS) diseases. The searching sites such as Science Direct and PubMed were used to find out the numerous distinct tracers across 16 CNS targets including tau, synaptic vesicle glycoprotein, the adenosine 2A receptor, the phosphodiesterase enzyme PDE10A, and the purinoceptor, among others. Among the most encouraging are [18 F]FIMX for mGluR imaging, [11 C]Martinostat for Histone deacetylase, [18 F]MNI-444 for adenosine 2A imaging, [11 C]ER176 for translocator protein, and [18 F]MK-6240 for tau imaging. We also reviewed the findings for each tracer's features and potential for application in CNS pathophysiology and therapeutic evaluation investigations, including target specificity, binding efficacy, and pharmacokinetic factors. This review aims to present a current evaluation of modern positron emission tomography tracers for CNS targets, with a focus on recent advances for targets that have newly emerged for imaging in humans.
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Affiliation(s)
- Priya Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Deepika Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Pooja Srivastava
- Division of Cyclotron and Radiopharmaceuticals Sciences, Institute of Nuclear Medicine and Allied Sciences, Delhi, India
| | - Gauri Mishra
- Department of Zoology, Swami Shraddhananad College, University of Delhi, Alipur, Delhi, India
| | - Anjani K Tiwari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
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9
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Tau PET imaging in progressive supranuclear palsy: a systematic review and meta-analysis. J Neurol 2023; 270:2451-2467. [PMID: 36633672 DOI: 10.1007/s00415-022-11556-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/28/2022] [Accepted: 12/28/2022] [Indexed: 01/13/2023]
Abstract
OBJECTIVES To evaluate the difference of tau burden between patients with progressive supranuclear palsy (PSP) and healthy controls (HCs) or other neurodegenerative diseases using tau-positron emission tomography (PET) imaging. METHODS A systematic search on PubMed, Embase, and Web of Science databases was performed for tau-PET studies in PSP patients, up to April 1, 2022. Standardized mean differences (SMDs) of tau tracer uptake were calculated using random-effects models. Subgroup analysis based on the type of tau tracers, meta-regression, and sensitivity analysis were conducted. RESULTS Twenty-seven studies comprising 553 PSP, 626 HCs, and 406 other neurodegenerative diseases were included. Compared with HCs, PSP patients showed elevated tau binding in basal ganglia, midbrain, dentate nucleus, cerebellar white matter, and frontal lobe with decreasing SMD (SMD: 0.390-1.698). Compared with Parkinson's disease patients, increased tau binding was identified in the midbrain, basal ganglia, dentate nucleus, and frontal and parietal lobe in PSP patients with decreasing SMD (SMD: 0.503-1.853). PSP patients showed higher tau binding in the subthalamic nucleus (SMD = 1.351) and globus pallidus (SMD = 1.000), and lower binding in the cortex and parahippocampal gyrus than Alzheimer's disease patients (SMD: - 2.976 to - 1.018). PSP patients showed higher midbrain tau binding than multiple system atrophy patients (SMD = 1.269). CONCLUSION Tau PET imaging indicates different topography of tau deposition between PSP patients and HCs or other neurodegenerative disorders. The affinity and selectivity of tracers for 4R-tau and the off-target binding of tracers should be considered when interpreting the results.
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10
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Abstract
Brain PET adds value in diagnosing neurodegenerative disorders, especially frontotemporal dementia (FTD) due to its syndromic presentation that overlaps with a variety of other neurodegenerative and psychiatric disorders. 18F-FDG-PET has improved sensitivity and specificity compared with structural MR imaging, with optimal diagnostic results achieved when both techniques are utilized. PET demonstrates superior sensitivity compared with SPECT for FTD diagnosis that is primarily a supplement to other imaging and clinical evaluations. Tau-PET and amyloid-PET primary use in FTD diagnosis is differentiation from Alzheimer disease, although these methods are limited mainly to research settings.
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Affiliation(s)
- Joshua Ward
- Division of Neuroradiology, Mallinckrodt Institute of Radiology, Washington University in Saint. Louis, Saint Louis, MO 63130, USA
| | - Maria Ly
- Division of Neuroradiology, Mallinckrodt Institute of Radiology, Washington University in Saint. Louis, Saint Louis, MO 63130, USA
| | - Cyrus A. Raji
- Division of Neuroradiology, Mallinckrodt Institute of Radiology, Washington University in Saint. Louis, Saint Louis, MO 63130, USA,Department of Neurology, Washington University in St. Louis, 4525 Scott Avenue, St. Louis, MO 63110, USA,Corresponding author. Division of Neuroradiology, Mallinckrodt Institute of Radiology, Washington University in Saint. Louis, Saint Louis, MO 63130.
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11
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Bartos LM, Kunte ST, Beumers P, Xiang X, Wind K, Ziegler S, Bartenstein P, Choi H, Lee DS, Haass C, von Baumgarten L, Tahirovic S, Albert NL, Lindner S, Brendel M. Single-Cell Radiotracer Allocation via Immunomagnetic Sorting to Disentangle PET Signals at Cellular Resolution. J Nucl Med 2022; 63:1459-1462. [PMID: 35589403 PMCID: PMC9536696 DOI: 10.2967/jnumed.122.264171] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
With great interest, our independent groups of scientists located in Korea and Germany recognized the use of a very similar methodologic approach to quantify the uptake of radioactive glucose (18F-FDG) at the cellular level. The focus of our investigations was to disentangle microglial 18F-FDG uptake. To do so, CD11b immunomagnetic cell sorting was applied to isolate microglia cells after in vivo 18F-FDG injection, to allow simple quantification via a γ-counter. Importantly, this technique reveals a snapshot of cellular glucose uptake in living mice at the time of injection since 18F-FDG is trapped by hexokinase phosphorylation without a further opportunity to be metabolized. Both studies indicated high 18F-FDG uptake of single CD11b-positive microglia cells and a significant increase in microglial 18F-FDG uptake when this cell type is activated in the presence of amyloid pathology. Furthermore, another study noticed that immunomagnetic cell sorting after tracer injection facilitated determination of high 18F-FDG uptake in myeloid cells in a range of tumor models. Here, we aim to discuss the rationale for single-cell radiotracer allocation via immunomagnetic cell sorting (scRadiotracing) by providing examples of promising applications of this innovative technology in neuroscience, oncology, and radiochemistry.
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Affiliation(s)
- Laura M Bartos
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Sebastian T Kunte
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Philipp Beumers
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Xianyuan Xiang
- Biomedical Center, Division of Metabolic Biochemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
- CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, and Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Karin Wind
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Sibylle Ziegler
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- Munich Cluster for Systems Neurology, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
- Munich Cluster for Systems Neurology, Munich, Germany
| | - Hongyoon Choi
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Soo Lee
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Christian Haass
- Biomedical Center, Division of Metabolic Biochemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
- CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, and Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- German Center for Neurodegenerative Diseases, Munich, Germany
| | - Louisa von Baumgarten
- Department of Neurosurgery, University Hospital of Munich, LMU Munich, Munich, Germany; and
- German Cancer Consortium, Munich, Germany
| | | | - Nathalie L Albert
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany;
- Munich Cluster for Systems Neurology, Munich, Germany
- German Center for Neurodegenerative Diseases, Munich, Germany
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12
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Roytman M, Chiang GC, Gordon ML, Franceschi AM. Multimodality Imaging in Primary Progressive Aphasia. AJNR Am J Neuroradiol 2022; 43:1230-1243. [PMID: 36007947 PMCID: PMC9451618 DOI: 10.3174/ajnr.a7613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 11/30/2021] [Indexed: 01/26/2023]
Abstract
Primary progressive aphasia is a clinically and neuropathologically heterogeneous group of progressive neurodegenerative disorders, characterized by language-predominant impairment and commonly associated with atrophy of the dominant language hemisphere. While this clinical entity has been recognized dating back to the 19th century, important advances have been made in defining our current understanding of primary progressive aphasia, with 3 recognized subtypes to date: logopenic variant, semantic variant, and nonfluent/agrammatic variant. Given the ongoing progress in our understanding of the neurobiology and genomics of these rare neurodegenerative conditions, accurate imaging diagnoses are of the utmost importance and carry implications for future therapeutic triaging. This review covers the diverse spectrum of primary progressive aphasia and its multimodal imaging features, including structural, functional, and molecular neuroimaging findings; it also highlights currently recognized diagnostic criteria, clinical presentations, histopathologic biomarkers, and treatment options of these 3 primary progressive aphasia subtypes.
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Affiliation(s)
- M Roytman
- From the Neuroradiology Division (M.R., G.C.C.), Department of Radiology, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York
| | - G C Chiang
- From the Neuroradiology Division (M.R., G.C.C.), Department of Radiology, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York
| | - M L Gordon
- Departments of Neurology and Psychiatry (M.L.G.), Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, The Litwin-Zucker Research Center, Feinstein Institutes for Medical Research, Manhasset, New York
| | - A M Franceschi
- Neuroradiology Division (A.M.F.), Department of Radiology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Lenox Hill Hospital, New York, New York
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13
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Xie J, Zhang Y, Li S, Wei H, Yu H, Zhou Q, Wei L, Ke D, Wang Q, Yang Y, Wang J. P301S-hTau acetylates KEAP1 to trigger synaptic toxicity via inhibiting NRF2/ARE pathway: A novel mechanism underlying hTau-induced synaptic toxicities. Clin Transl Med 2022; 12:e1003. [PMID: 35917404 PMCID: PMC9345400 DOI: 10.1002/ctm2.1003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 07/11/2022] [Accepted: 07/18/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Human Tau (hTau) accumulation and synapse loss are two pathological hallmarks of tauopathies. However, whether and how hTau exerts toxic effects on synapses remain elusive. METHODS Mutated hTau (P301S) was overexpressed in the N2a cell line, primary hippocampal neurons and hippocampal CA3. Western blotting and quantitative polymerase chain reaction were applied to examine the protein and mRNA levels of synaptic proteins. The protein interaction was tested by co-immunoprecipitation and proximity ligation assays. Memory and emotion status were evaluated by a series of behavioural tests. The transcriptional activity of nuclear factor-erythroid 2-related factor 2 (NRF2) was detected by dual luciferase reporter assay. Electrophoresis mobility shift assay and chromosome immunoprecipitation were conducted to examine the combination of NRF2 to specific anti-oxidative response element (ARE) sequences. Neuronal morphology was analysed after Golgi staining. RESULTS Overexpressing P301S decreased the protein levels of post-synaptic density protein 93 (PSD93), PSD95 and synapsin 1 (SYN1). Simultaneously, NRF2 was decreased, whereas Kelch-like ECH-associated protein 1 (KEAP1) was elevated. Further, we found that NRF2 could bind to the specific AREs of DLG2, DLG4 and SYN1 genes, which encode PSD93, PSD95 and SYN1, respectively, to promote their expression. Overexpressing NRF2 ameliorated P301S-reduced synaptic proteins and synapse. By means of acetylation at K312, P301S increased the protein level of KEAP1 via inhibiting KEAP1 degradation from ubiquitin-proteasome pathway, thereby decreasing NRF2 and reducing synapse. Blocking the P301S-KEAP1 interaction at K312 rescued the P301S-suppressed expression of synaptic proteins and memory deficits with anxiety efficiently. CONCLUSIONS P301S-hTau could acetylate KEAP1 to trigger synaptic toxicity via inhibiting the NRF2/ARE pathway. These findings provide a novel and potential target for the therapeutic intervention of tauopathies.
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Affiliation(s)
- Jia‐Zhao Xie
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Yao Zhang
- Endocrine Department of Liyuan HospitalKey Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Shi‐Hong Li
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Hui Wei
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Hui‐Ling Yu
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Qiu‐Zhi Zhou
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Lin‐Yu Wei
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Dan Ke
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Qun Wang
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Ying Yang
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Jian‐Zhi Wang
- Department of PathophysiologySchool of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Co‐Innovation Center of NeuroregenerationNantong UniversityNantongChina
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14
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Malpetti M, La Joie R. Imaging Alzheimer's pathology stage by stage. NATURE AGING 2022; 2:465-467. [PMID: 37118453 DOI: 10.1038/s43587-022-00236-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Affiliation(s)
- Maura Malpetti
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Renaud La Joie
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
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15
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Chen B, Marquez-Nostra B, Belitzky E, Toyonaga T, Tong J, Huang Y, Cai Z. PET Imaging in Animal Models of Alzheimer’s Disease. Front Neurosci 2022; 16:872509. [PMID: 35685772 PMCID: PMC9171374 DOI: 10.3389/fnins.2022.872509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
The successful development and translation of PET imaging agents targeting β-amyloid plaques and hyperphosphorylated tau tangles have allowed for in vivo detection of these hallmarks of Alzheimer’s disease (AD) antemortem. Amyloid and tau PET have been incorporated into the A/T/N scheme for AD characterization and have become an integral part of ongoing clinical trials to screen patients for enrollment, prove drug action mechanisms, and monitor therapeutic effects. Meanwhile, preclinical PET imaging in animal models of AD can provide supportive information for mechanistic studies. With the recent advancement of gene editing technologies and AD animal model development, preclinical PET imaging in AD models will further facilitate our understanding of AD pathogenesis/progression and the development of novel treatments. In this study, we review the current state-of-the-art in preclinical PET imaging using animal models of AD and suggest future research directions.
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Sible IJ, Nation DA. Visit-to-Visit Blood Pressure Variability and Longitudinal Tau Accumulation in Older Adults. Hypertension 2022; 79:629-637. [PMID: 34967222 PMCID: PMC8979412 DOI: 10.1161/hypertensionaha.121.18479] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/16/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND Elevated blood pressure variability (BPV) is predictive of dementia, independent of average blood pressure levels, but neuropathological mechanisms remain unclear. We examined whether BPV in older adults is related to tau accumulation in brain regions vulnerable to Alzheimer disease and whether relationships are modified by apoϵ4 carrier status. METHODS Two hundred eighty-six Alzheimer's Disease Neuroimaging Initiative participants without history of dementia underwent 3 to 4 blood pressure measurements over 12 months and ≥1 tau positron emission tomography thereafter. BPV was calculated as variability independent of mean. Each scan determined tau burden (standardized uptake value ratio) for a temporal meta-region of interest, including burden from entorhinal cortex, amygdala, parahippocampus, fusiform, inferior temporal, and middle temporal. Bayesian linear growth modeling examined the role of BPV, apolipoprotein ϵ4 carrier status, and time on regional tau accumulation after controlling for several variables, including baseline hypertension. RESULTS Elevated BPV was related to tau accumulation at follow-up in a temporal meta-region, independent of average blood pressure levels (ß, 0.89 [95% credible interval, 0.86-0.92]) and especially in entorhinal cortex (ß, 2.57 [95% credible interval, 2.15-2.99]). Apoϵ4 carriers with elevated BPV had the fastest tau accumulation at follow-up (ß, 1.73 [95% credible interval, 0.47-3.03]). CONCLUSIONS BPV is related to tau accumulation in brain regions vulnerable to Alzheimer disease, independent of average blood pressure. APOEϵ4 modified this relationship. Bidirectionality of findings is possible. BPV may represent a marker of vascular dysfunction related to early-stage tau pathology contributing to Alzheimer disease.
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Affiliation(s)
- Isabel J. Sible
- Department of Psychology, University of Southern California, Los Angeles, CA 90007, USA
| | - Daniel A. Nation
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
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17
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Imaging Clinical Subtypes and Associated Brain Networks in Alzheimer’s Disease. Brain Sci 2022; 12:brainsci12020146. [PMID: 35203910 PMCID: PMC8869882 DOI: 10.3390/brainsci12020146] [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: 12/15/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/17/2022] Open
Abstract
Alzheimer’s disease (AD) does not present uniform symptoms or a uniform rate of progression in all cases. The classification of subtypes can be based on clinical symptoms or patterns of pathological brain alterations. Imaging techniques may allow for the identification of AD subtypes and their differentiation from other neurodegenerative diseases already at an early stage. In this review, the strengths and weaknesses of current clinical imaging methods are described. These include positron emission tomography (PET) to image cerebral glucose metabolism and pathological amyloid or tau deposits. Magnetic resonance imaging (MRI) is more widely available than PET. It provides information on structural or functional changes in brain networks and their relation to AD subtypes. Amyloid PET provides a very early marker of AD but does not distinguish between AD subtypes. Regional patterns of pathology related to AD subtypes are observed with tau and glucose PET, and eventually as atrophy patterns on MRI. Structural and functional network changes occur early in AD but have not yet provided diagnostic specificity.
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18
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Zhou Y, Li J, Nordberg A, Ågren H. Dissecting the Binding Profile of PET Tracers to Corticobasal Degeneration Tau Fibrils. ACS Chem Neurosci 2021; 12:3487-3496. [PMID: 34464084 PMCID: PMC8447187 DOI: 10.1021/acschemneuro.1c00536] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
![]()
Alzheimer’s
disease and primary tauopathies are characterized
by the presence of tau pathology in brain. Several tau positron emission
tomography (PET) tracers have been developed and studied in Alzheimer’s
disease (AD), but there is still a lack of 4R-tau specific tracers
for non-AD tauopathies. We here present the first computational study
on the binding profiles of four tau different PET tracers, PI2620,
CBD2115, PM-PBB3, and MK6240, to corticobasal degeneration (CBD) tau.
The in silico results showed different preferences
for the various binding sites on the 4R fibril, and especially an
entry site, a concave site, and a core site showed high binding affinity
to these tracers. The core site and entry site both showed higher
binding affinity than the surface sites, but the tracers were less
likely to enter these sites. PI2620, CBD2115, and PM-PBB3 all showed
higher binding affinities to CBD tau than the 3R/4R tracer MK6240.
The same strategy has also been applied to AD tau fibrils, and significant
differences in selectivity of binding sites were also observed. A
higher binding affinity was observed for CBD2115 and PM-PBB3 to AD
tau compared to PI2620. None of the studied tracers showed a selectivity
for 4R compared to 3R/4R tau. This study clearly shows that identified
binding sites from cryo-EM with low resolution can be further refined
by metadynamics simulations in order to provide atomic resolution
of the binding modes as well as of the thermodynamic properties.
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Affiliation(s)
- Yang Zhou
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Junhao Li
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, 141 84, Stockholm, Sweden
- Theme Aging Karolinska University Hospital, S-141 86 Stockholm, Sweden
| | - Hans Ågren
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
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Colato E, Chiotis K, Ferreira D, Mazrina MS, Lemoine L, Mohanty R, Westman E, Nordberg A, Rodriguez-Vieitez E. Assessment of Tau Pathology as Measured by 18F-THK5317 and 18F-Flortaucipir PET and Their Relation to Brain Atrophy and Cognition in Alzheimer's Disease. J Alzheimers Dis 2021; 84:103-117. [PMID: 34511502 PMCID: PMC8609906 DOI: 10.3233/jad-210614] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND In Alzheimer's disease (AD), the abnormal aggregation of hyperphosphorylated tau leads to synaptic dysfunction and neurodegeneration. Recently developed tau PET imaging tracers are candidate biomarkers for diagnosis and staging of AD. OBJECTIVE We aimed to investigate the discriminative ability of 18F-THK5317 and 18F-flortaucipir tracers and brain atrophy at different stages of AD, and their respective associations with cognition. METHODS Two cohorts, each including 29 participants (healthy controls [HC], prodromal AD, and AD dementia patients), underwent 18F-THK5317 or 18F-flortaucipir PET, T1-weighted MRI, and neuropsychological assessment. For each subject, we quantified regional 18F-THK5317 and 18F-flortaucipir uptake within six bilateral and two composite regions of interest. We assessed global brain atrophy for each individual by quantifying the brain volume index, a measure of brain volume-to-cerebrospinal fluid ratio. We then quantified the discriminative ability of regional 18F-THK5317, 18F-flortaucipir, and brain volume index between diagnostic groups, and their associations with cognition in patients. RESULTS Both 18F-THK5317 and 18F-flortaucipir outperformed global brain atrophy in discriminating between HC and both prodromal AD and AD dementia groups. 18F-THK5317 provided the highest discriminative ability between HC and prodromal AD groups. 18F-flortaucipir performed best at discriminating between prodromal and dementia stages of AD. Across all patients, both tau tracers were predictive of RAVL learning, but only 18F-flortaucipir predicted MMSE. CONCLUSION Our results warrant further in vivo head-to-head and antemortem-postmortem evaluations. These validation studies are needed to select tracers with high clinical validity as biomarkers for early diagnosis, prognosis, and disease staging, which will facilitate their incorporation in clinical practice and therapeutic trials.
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Affiliation(s)
- Elisa Colato
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Konstantinos Chiotis
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Daniel Ferreira
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Mariam S Mazrina
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Laetitia Lemoine
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Rosaleena Mohanty
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Eric Westman
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Theme Aging, Karolinska University Hospital, Stockholm, Sweden
| | - Elena Rodriguez-Vieitez
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
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The Evaluation of Tau Deposition with [ 18F]PI-2620 by Using a Semiquantitative Method in Cognitively Normal Subjects and Patients with Mild Cognitive Impairment and Alzheimer's Disease. Mol Imaging 2021; 2021:6640054. [PMID: 34381315 PMCID: PMC8328488 DOI: 10.1155/2021/6640054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/18/2021] [Accepted: 06/22/2021] [Indexed: 11/18/2022] Open
Abstract
Background Some studies have reported the effectiveness of [18F]PI-2620 as an effective tau-binding radiotracer; however, few reports have applied semiquantitative analysis to the tracer. Therefore, this study's aim was to perform a semiquantitative analysis of [18F]PI-2620 in individuals with normal cognition and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Methods Twenty-six cognitively normal (CN) subjects, 7 patients with AD, and 36 patients with MCI were enrolled. A dynamic positron emission tomography (PET) scan was performed 30–75 min postinjection. PET and T1-weighted magnetic resonance imaging scans were coregistered. The standardized uptake value ratio (SUVr) was used for semiquantitative analysis. The P-Mod software was applied to create volumes of interest. The ANOVA and post hoc Tukey HSD were used for statistical analysis. Results In the AD group, the occipital lobe had a significantly higher mean SUVr (1.46 ± 0.57) than in the CN and MCI groups. Compared with the CN group, the AD group showed significantly higher mean SUVr in the fusiform gyrus (1.06 ± 0.09 vs. 1.49 ± 0.86), inferior temporal (1.07 ± 0.07 vs. 1.46 ± 0.08), parietal lobe, lingual gyrus, and precuneus regions. Similarly, the AD group demonstrated a higher mean SUVr than the MCI group in the precuneus, lingual, inferior temporal, fusiform, supramarginal, orbitofrontal, and superior temporal regions. The remaining observed regions, including the striatum, basal ganglia, thalamus, and white matter, showed a low SUVr across all groups with no statistically significant differences. Conclusion A significantly higher mean SUVr of [18F]PI-2620 was observed in the AD group; a significant area of the brain in the AD group demonstrated tau protein deposit in concordance with Braak Stages III–V, providing useful information to differentiate AD from CN and MCI. Moreover, the low SUVr in the deep striatum and thalamus could be useful for excluding primary tauopathies.
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21
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Willroider M, Roeber S, Horn AKE, Arzberger T, Scheifele M, Respondek G, Sabri O, Barthel H, Patt M, Mishchenko O, Schildan A, Mueller A, Koglin N, Stephens A, Levin J, Höglinger GU, Bartenstein P, Herms J, Brendel M, Beyer L. Superiority of Formalin-Fixed Paraffin-Embedded Brain Tissue for in vitro Assessment of Progressive Supranuclear Palsy Tau Pathology With [ 18 F]PI-2620. Front Neurol 2021; 12:684523. [PMID: 34276540 PMCID: PMC8282895 DOI: 10.3389/fneur.2021.684523] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives: Autoradiography on brain tissue is used to validate binding targets of newly discovered radiotracers. The purpose of this study was to correlate quantification of autoradiography signal using the novel next-generation tau positron emission tomography (PET) radiotracer [18F]PI-2620 with immunohistochemically determined tau-protein load in both formalin-fixed paraffin-embedded (FFPE) and frozen tissue samples of patients with Alzheimer's disease (AD) and Progressive Supranuclear Palsy (PSP). Methods: We applied [18F]PI-2620 autoradiography to postmortem cortical brain samples of six patients with AD, five patients with PSP and five healthy controls, respectively. Binding intensity was compared between both tissue types and different disease entities. Autoradiography signal quantification (CWMR = cortex to white matter ratio) was correlated with the immunohistochemically assessed tau load (AT8-staining, %-area) for FFPE and frozen tissue samples in the different disease entities. Results: In AD tissue, relative cortical tracer binding was higher in frozen samples when compared to FFPE samples (CWMRfrozen vs. CWMRFFPE: 2.5-fold, p < 0.001), whereas the opposite was observed in PSP tissue (CWMRfrozen vs. CWMRFFPE: 0.8-fold, p = 0.004). In FFPE samples, [18F]PI-2620 autoradiography tracer binding and immunohistochemical tau load correlated significantly for both PSP (R = 0.641, p < 0.001) and AD tissue (R = 0.435, p = 0.016), indicating a high agreement of relative tracer binding with underlying pathology. In frozen tissue, the correlation between autoradiography and immunohistochemistry was only present in AD (R = 0.417, p = 0.014) but not in PSP tissue (R = -0.115, p = n.s.). Conclusion: Our head-to-head comparison indicates that FFPE samples show superiority over frozen samples for autoradiography assessment of PSP tau pathology by [18F]PI-2620. The [18F]PI-2620 autoradiography signal in FFPE samples reflects AT8 positive tau in samples of both PSP and AD patients.
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Affiliation(s)
- Marie Willroider
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Sigrun Roeber
- Center for Neuropathology and Prion Research, LMU Munich, Munich, Germany
| | - Anja K E Horn
- Institute of Anatomy and Cell Biology, LMU Munich, Munich, Germany
| | - Thomas Arzberger
- Center for Neuropathology and Prion Research, LMU Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Maximilian Scheifele
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Gesine Respondek
- Department of Neurology, Hannover Medical School, Hanover, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Henryk Barthel
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Olena Mishchenko
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Andreas Schildan
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | | | | | | | - Johannes Levin
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Department of Neurology, University Hospital Munich, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Günter U Höglinger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Department of Neurology, Hannover Medical School, Hanover, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Department of Neurology, Technical University Munich, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Jochen Herms
- Center for Neuropathology and Prion Research, LMU Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Leonie Beyer
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany.,Center for Neuropathology and Prion Research, LMU Munich, Munich, Germany
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22
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Feasibility of short imaging protocols for [ 18F]PI-2620 tau-PET in progressive supranuclear palsy. Eur J Nucl Med Mol Imaging 2021; 48:3872-3885. [PMID: 34021393 PMCID: PMC8484138 DOI: 10.1007/s00259-021-05391-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 04/26/2021] [Indexed: 11/08/2022]
Abstract
Purpose Dynamic 60-min positron emission tomography (PET) imaging with the novel tau radiotracer [18F]PI-2620 facilitated accurate discrimination between patients with progressive supranuclear palsy (PSP) and healthy controls (HCs). This study investigated if truncated acquisition and static time windows can be used for [18F]PI-2620 tau-PET imaging of PSP. Methods Thirty-seven patients with PSP Richardson syndrome (PSP-RS) were evaluated together with ten HCs. [18F]PI-2620 PET was performed by a dynamic 60-min scan. Distribution volume ratios (DVRs) were calculated using full and truncated scan durations (0–60, 0–50, 0–40, 0–30, and 0–20 min p.i.). Standardized uptake value ratios (SUVrs) were obtained 20–40, 30–50, and 40–60 min p.i.. All DVR and SUVr data were compared with regard to their potential to discriminate patients with PSP-RS from HCs in predefined subcortical and cortical target regions (effect size, area under the curve (AUC), multi-region classifier). Results 0–50 and 0–40 DVR showed equivalent effect sizes as 0–60 DVR (averaged Cohen’s d: 1.22 and 1.16 vs. 1.26), whereas the performance dropped for 0–30 or 0–20 DVR. The 20–40 SUVr indicated the best performance of all static acquisition windows (averaged Cohen’s d: 0.99). The globus pallidus internus discriminated patients with PSP-RS and HCs at a similarly high level for 0–60 DVR (AUC: 0.96), 0–40 DVR (AUC: 0.96), and 20–40 SUVr (AUC: 0.94). The multi-region classifier sensitivity of these time windows was consistently 86%. Conclusion Truncated and static imaging windows can be used for [18F]PI-2620 PET imaging of PSP. 0–40 min dynamic scanning offers the best balance between accuracy and economic scanning. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-021-05391-3.
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23
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Watanabe H, Kishimoto T, Kaide S, Tarumizu Y, Tatsumi H, Iikuni S, Ono M. Characterization and Optimization of Benzimidazopyrimidine and Pyridoimidazopyridine Derivatives as Tau-SPECT Probes. ACS Med Chem Lett 2021; 12:805-811. [PMID: 34055229 DOI: 10.1021/acsmedchemlett.1c00071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/20/2021] [Indexed: 01/15/2023] Open
Abstract
The accumulation of hyperphosphorylated tau protein in the brain is regarded as one of the hallmarks of Alzheimer's disease (AD). In vivo imaging of tau aggregates is helpful for diagnosis and monitoring of the progression of AD. In this study, we designed and synthesized novel radioiodinated benzimidazopyrimidine (BIPM) and pyridoimidazopyridine (PIP) derivatives with a monomethylamino, monoethylamino, monopropylamino, or diethylamino group as tau imaging probes for single-photon-emission computed tomography (SPECT). On in vitro autoradiography with AD brain sections, [125I]PIP-NHMe showed the highest selective binding affinity for tau aggregates among the radioiodinated BIPM and PIP derivatives. In a biodistribution study using normal mice, [125I]PIP-NHMe and [125I]PIP-NHEt displayed high initial uptake (6.62 and 6.86% ID/g, respectively, at 2 min postinjection) into and rapid clearance from the brain, with brain2 min/brain30 min ratios of 38.9 and 28.6, respectively. These results suggest that [123I]PIP-NHMe may be a novel SPECT probe that is useful for detecting tau aggregates in the AD brain.
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Affiliation(s)
- Hiroyuki Watanabe
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takeaki Kishimoto
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Sho Kaide
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuta Tarumizu
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Haruka Tatsumi
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shimpei Iikuni
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masahiro Ono
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
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24
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Sathekge MM, Bouchelouche K. Letter from the Editors. Semin Nucl Med 2021; 51:193-195. [PMID: 33745660 DOI: 10.1053/j.semnuclmed.2021.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Cecchin D, Garibotto V, Law I, Goffin K. PET Imaging in Neurodegeneration and Neuro-oncology: Variants and Pitfalls. Semin Nucl Med 2021; 51:408-418. [PMID: 33820651 DOI: 10.1053/j.semnuclmed.2021.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In neurodegenerative diseases, positron emission tomography (PET) imaging plays an important role in the early identification and differential diagnosis in particular in clinically challenging patients. 18F-FDG is still the most widely used and established tracer in this patient group, with different cortical and subcortical regions being preferentially affected in different neurodegenerative diseases, such as frontotemporal dementia, Alzheimer's disease or Lewy Body dementia, resulting in typical hypometabolic patterns. Over the last decades, however, the implementation of tracers specific for the pathological deposits characteristic of the different diseases, such as amyloid and tau, has revolutionized the way of classifying and reporting cases of cognitive impairment of neurodegenerative origin, providing complementary information to 18F-FDG PET. In neuro-oncology, PET imaging can be performed in several clinical indications, as highlighted in the joint European Association of Nuclear Medicine (EANM)/European Association of Neuro-Oncology (EANO)/Response assessment in neuro-oncology (RANO) practice guidelines on imaging in neuro-oncology. For assessment of glioma, amino-acid analogues, such as 11C-methionine or 18F-FET, are used whenever clinically available, as they offer excellent tumor-to-background ratios in malignant tumors. Moreover, dynamic acquisition of amino-acid analogue tracers and assessment of the shape of the time-activity curve can be used to perform noninvasive grading of brain gliomas, differentiating low from high grade presentations. In both settings, however, thorough knowledge of the normal physiological tracer distribution and the variants and pitfalls that can occur during image acquisition, processing and interpretation is mandatory in order to provide optimal diagnostic information to referring physicians and patients. Especially in neuro-oncology, this process can be aided by the active use of coregistered magnetic resonance imaging to accurately identify the imaging correlates of developmental origin, acute and chronic stroke, inflammation, infection and seizure related activity.
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Affiliation(s)
- Diego Cecchin
- Nuclear Medicine Unit, Department of Medicine DIMED, Padua University Hospital, Padua, Italy
| | - Valentina Garibotto
- Nuclear Medicine and Molecular Imaging Division, Diagnostic Department, University Hospitals of Geneva and NIMTLab, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark
| | - Karolien Goffin
- Department of Nuclear Medicine, University Hospital Leuven, Division of Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium.
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