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Sheng L, Bhalla R. Biomarkers and Target-Specific Small-Molecule Drugs in Alzheimer's Diagnostic and Therapeutic Research: From Amyloidosis to Tauopathy. Neurochem Res 2024; 49:2273-2302. [PMID: 38844706 PMCID: PMC11310295 DOI: 10.1007/s11064-024-04178-w] [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: 01/16/2024] [Revised: 03/31/2024] [Accepted: 05/22/2024] [Indexed: 08/09/2024]
Abstract
Alzheimer's disease (AD) is the most common type of human dementia and is responsible for over 60% of diagnosed dementia cases worldwide. Abnormal deposition of β-amyloid and the accumulation of neurofibrillary tangles have been recognised as the two pathological hallmarks targeted by AD diagnostic imaging as well as therapeutics. With the progression of pathological studies, the two hallmarks and their related pathways have remained the focus of researchers who seek for AD diagnostic and therapeutic strategies in the past decades. In this work, we reviewed the development of the AD biomarkers and their corresponding target-specific small molecule drugs for both diagnostic and therapeutic applications, underlining their success, failure, and future possibilities.
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Affiliation(s)
- Li Sheng
- Centre for Advanced Imaging, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia.
| | - Rajiv Bhalla
- Centre for Advanced Imaging, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
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2
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Wagatsuma K, Miwa K, Yamao T, Kamitaka Y, Akamatsu G, Nakajima K, Miyaji N, Ishibashi K, Ishii K. Development of a novel phantom for tau PET imaging. Phys Med 2024; 123:103399. [PMID: 38852366 DOI: 10.1016/j.ejmp.2024.103399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 06/02/2024] [Accepted: 06/05/2024] [Indexed: 06/11/2024] Open
Abstract
PURPOSE The cortical uptake of tau positron emission tomography (PET) tracers corresponds to the Braak stage and reflects the distribution and progression of tau neurofibrillary tangles. The present study aimed to develop and validate the basic performance of a novel tau PET phantom, as well as to establish standard test procedures and analytical methods. METHODS The tau PET phantom consisted of a brain simulation section simulated medial temporal lobe region and resolution and uniformity sections. The brain simulation section and hot rods and uniformity section contained 4 and 2 kBq/mL of 18F, respectively and images were acquired three times for 20 min with a PET/CT scanner. The resolution section was visually assessed with two sets of hot and cold rods. Recovery coefficients (RCs) as a quantitative value and coefficient of variation (CV) as image noise were determined based on the brain simulation and the uniformity section, respectively. RESULTS Preparation of activity in the phantom was repeatable among three measurements. The quality of images in the brain simulation and uniformity section with the rods was good. The 5- or 6-mm rods were detected separately. The mean RCs calculated based on the VOI template were between 0.75 and 0.83. The CV at the center slice of uniformity section was 5.54%. CONCLUSIONS We developed a novel tau PET phantom to assess quantitative value, image noise, and detectability and resolution from brain simulation section, uniformity section, and rods, respectively. This phantom will contribute to the standardization and harmonization of tau PET imaging.
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Affiliation(s)
- Kei Wagatsuma
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan; Research Team for Neuroimaging, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2, Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan.
| | - Kenta Miwa
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, 10-6 Sakaemachi, Fukushima-shi, Fukushima 960-8516, Japan
| | - Tensho Yamao
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, 10-6 Sakaemachi, Fukushima-shi, Fukushima 960-8516, Japan
| | - Yuto Kamitaka
- Research Team for Neuroimaging, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2, Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Go Akamatsu
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kanta Nakajima
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Noriaki Miyaji
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, 10-6 Sakaemachi, Fukushima-shi, Fukushima 960-8516, Japan
| | - Kenji Ishibashi
- Research Team for Neuroimaging, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2, Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Kenji Ishii
- Research Team for Neuroimaging, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2, Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
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3
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Sanabria Bohórquez SM, Baker S, Manser PT, Tonietto M, Galli C, Wildsmith KR, Zou Y, Kerchner GA, Weimer R, Teng E. Evaluation of partial volume correction and analysis of longitudinal [ 18F]GTP1 tau PET imaging in Alzheimer's disease using linear mixed-effects models. FRONTIERS IN NEUROIMAGING 2024; 3:1355402. [PMID: 38606196 PMCID: PMC11008283 DOI: 10.3389/fnimg.2024.1355402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 02/29/2024] [Indexed: 04/13/2024]
Abstract
Purpose We evaluated the impact of partial volume correction (PVC) methods on the quantification of longitudinal [18F]GTP1 tau positron-emission tomography (PET) in Alzheimer's disease and the suitability of describing the tau pathology burden temporal trajectories using linear mixed-effects models (LMEM). Methods We applied van Cittert iterative deconvolution (VC), 2-compartment, and 3-compartment, and the geometric transfer matrix plus region-based voxelwise methods to data acquired in an Alzheimer's disease natural history study over 18 months at a single imaging site. We determined the optimal PVC method by comparing the standardized uptake value ratio change (%ΔSUVR) between diagnostic and tau burden-level groups and the longitudinal repeatability derived from the LMEM. The performance of LMEM analysis for calculating %ΔSUVR was evaluated in a natural history study and in a multisite clinical trial of semorinemab in prodromal to mild Alzheimer's disease by comparing results to traditional per-visit estimates. Results The VC, 2-compartment, and 3-compartment PVC methods had similar performance, whereas region-based voxelwise overcorrected regions with a higher tau burden. The lowest within-subject variability and acceptable group separation scores were observed without PVC. The LMEM-derived %ΔSUVR values were similar to the per-visit estimates with lower variability. Conclusion The results indicate that the tested PVC methods do not offer a clear advantage or improvement over non-PVC images for the quantification of longitudinal [18F]GTP1 PET data. LMEM offers a robust framework for the longitudinal tau PET quantification with low longitudinal test-retest variability. Clinical trial registration NCT02640092 and NCT03289143.
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Affiliation(s)
| | - Suzanne Baker
- Clinical Imaging Group, Genentech, Inc., South San Francisco, CA, United States
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Paul T. Manser
- Biostatistics, Genentech, Inc., South San Francisco, CA, United States
| | - Matteo Tonietto
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Christopher Galli
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | | | - Yixuan Zou
- Data and Statistical Science, Product Development, Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Geoffrey A. Kerchner
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Robby Weimer
- Translational Imaging, Genentech, Inc., South San Francisco, CA, United States
| | - Edmond Teng
- Early Clinical Development, Genentech, Inc., South San Francisco, CA, United States
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4
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Chisholm TS, Hunter CA. A closer look at amyloid ligands, and what they tell us about protein aggregates. Chem Soc Rev 2024; 53:1354-1374. [PMID: 38116736 DOI: 10.1039/d3cs00518f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The accumulation of amyloid fibrils is characteristic of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease. Detecting these fibrils with fluorescent or radiolabelled ligands is one strategy for diagnosing and better understanding these diseases. A vast number of amyloid-binding ligands have been reported in the literature as a result. To obtain a better understanding of how amyloid ligands bind, we have compiled a database of 3457 experimental dissociation constants for 2076 unique amyloid-binding ligands. These ligands target Aβ, tau, or αSyn fibrils, as well as relevant biological samples including AD brain homogenates. From this database significant variation in the reported dissociation constants of ligands was found, possibly due to differences in the morphology of the fibrils being studied. Ligands were also found to bind to Aβ(1-40) and Aβ(1-42) fibrils with similar affinities, whereas a greater difference was found for binding to Aβ and tau or αSyn fibrils. Next, the binding of ligands to fibrils was shown to be largely limited by the hydrophobic effect. Some Aβ ligands do not fit into this hydrophobicity-limited model, suggesting that polar interactions can play an important role when binding to this target. Finally several binding site models were outlined for amyloid fibrils that describe what ligands target what binding sites. These models provide a foundation for interpreting and designing site-specific binding assays.
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Affiliation(s)
- Timothy S Chisholm
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1 EW, UK.
| | - Christopher A Hunter
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1 EW, UK.
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5
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Smith M, Knight IS, Kormos RC, Pepe JG, Kunach P, Diamond MI, Shahmoradian SH, Irwin JJ, DeGrado WF, Shoichet BK. Docking for Molecules That Bind in a Symmetric Stack with SymDOCK. J Chem Inf Model 2024; 64:425-434. [PMID: 38191997 PMCID: PMC10806807 DOI: 10.1021/acs.jcim.3c01749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/10/2024]
Abstract
Discovering ligands for amyloid fibrils, such as those formed by the tau protein, is an area of great current interest. In recent structures, ligands bind in stacks in the tau fibrils to reflect the rotational and translational symmetry of the fibril itself; in these structures, the ligands make few interactions with the protein but interact extensively with each other. To exploit this symmetry and stacking, we developed SymDOCK, a method to dock molecules that follow the protein's symmetry. For each prospective ligand pose, we apply the symmetry operation of the fibril to generate a self-interacting and fibril-interacting stack, checking that doing so will not cause a clash between the original molecule and its image. Absent a clash, we retain that pose and add the ligand-ligand van der Waals energy to the ligand's docking score (here using DOCK3.8). We can check these geometries and energies using an implementation of ANI, a neural-network-based quantum-mechanical evaluation of the ligand stacking energies. In retrospective calculations, symmetry docking can reproduce the poses of three tau PET tracers whose structures have been determined. More convincingly, in a prospective study, SymDOCK predicted the structure of the PET tracer MK-6240 bound in a symmetrical stack to AD PHF tau before that structure was determined; the docked pose was used to determine how MK-6240 fit the cryo-EM density. In proof-of-concept studies, SymDOCK enriched known ligands over property-matched decoys in retrospective screens without sacrificing docking speed and can address large library screens that seek new symmetrical stackers. Future applications of this approach will be considered.
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Affiliation(s)
- Matthew
S. Smith
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
- Program
in Biophysics, University of California, UCSF Genentech Hall MC2240, 600
16th St Rm N474D,San Francisco, California 94143, United States
| | - Ian S. Knight
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
| | - Rian C. Kormos
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
- Program
in Biophysics, University of California, UCSF Genentech Hall MC2240, 600
16th St Rm N474D,San Francisco, California 94143, United States
| | - Joseph G. Pepe
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
- Program
in Biophysics, University of California, UCSF Genentech Hall MC2240, 600
16th St Rm N474D,San Francisco, California 94143, United States
| | - Peter Kunach
- McGill
Research Centre for Studies in Aging, McGill
University, 6875 Boulevard LaSalle, Montreal, Quebec H4H 1R3, Canada
- Department
of Neurology and Neurosurgery, McGill University, 1033 Pine Avenue West, Room 310, Montreal, Quebec H3A 1A1, Canada
- Center
for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell
Jr. Brain Institute, University of Texas
Southwestern Medical Center, 6124 Harry Hines Blvd. Suite NS03.200, Dallas, Texas 75390, United States
- Department
of Neurology, University of Texas Southwestern
Medical Center, 5323 Harry Hines Blvd., G2.222, Dallas, Texas 75390-9368, United States
- Department
of Neuroscience, University of Texas Southwestern
Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9111, United States
| | - Marc I. Diamond
- Center
for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell
Jr. Brain Institute, University of Texas
Southwestern Medical Center, 6124 Harry Hines Blvd. Suite NS03.200, Dallas, Texas 75390, United States
- Department
of Neurology, University of Texas Southwestern
Medical Center, 5323 Harry Hines Blvd., G2.222, Dallas, Texas 75390-9368, United States
- Department
of Neuroscience, University of Texas Southwestern
Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9111, United States
| | - Sarah H. Shahmoradian
- Center
for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell
Jr. Brain Institute, University of Texas
Southwestern Medical Center, 6124 Harry Hines Blvd. Suite NS03.200, Dallas, Texas 75390, United States
- Department
of Biophysics, University of Texas Southwestern
Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-8816, United States
| | - John J. Irwin
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
| | - William F. DeGrado
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
- Cardiovascular
Research Institute, University of California, 555 Mission Bay Blvd South, PO Box 589001, San Francisco, California 94158-9001, United
States
| | - Brian K. Shoichet
- Department
of Pharmaceutical Chemistry, University
of California, UCSF Genentech
Hall Box 2280, 600 16th St Rm 518,San Francisco, California 94158, United States
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6
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Taha A, Alassi A, Gjedde A, Wong DF. Transforming Neurology and Psychiatry: Organ-specific PET Instrumentation and Clinical Applications. PET Clin 2024; 19:95-103. [PMID: 37813719 DOI: 10.1016/j.cpet.2023.06.002] [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] [Indexed: 10/11/2023]
Abstract
PET technology has immense potential for furthering understanding of the brain and associated disorders, including advancements in high-resolution tomographs and hybrid imaging modalities. Novel radiotracers targeting specific neurotransmitter systems and molecular markers provide opportunities to unveil intricate mechanisms underlying neurologic and psychiatric conditions. As PET imaging techniques and analysis methods continue to be refined, the field is poised to make significant contributions to personalized medicine for more targeted and effective interventions. PET instrumentation has advanced the fields of neurology and psychiatry, providing insights into pathophysiology and development of effective treatments.
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Affiliation(s)
- Ahmed Taha
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA
| | - Amer Alassi
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA
| | - Albert Gjedde
- Department of Clinical Medicine, Translational Neuropsychiatry Unit, Aarhus University, Denmark; Department of Neuroscience, University of Copenhagen, Denmark
| | - Dean F Wong
- Mallinckrodt Institute of Radiology, Departments of Radiology, Psychiatry, Neurology, Neuroscience, Washington University in St Louis, Saint Louis, MO, USA.
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7
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Mishra S. Emerging Trends in Cryo-EM-based Structural Studies of Neuropathological Amyloids. J Mol Biol 2023; 435:168361. [PMID: 37949311 DOI: 10.1016/j.jmb.2023.168361] [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: 09/29/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Tauopathies, synucleinopathies, Aβ amyloidosis, TDP-43 proteinopathies, and prion diseases- these neurodegenerative diseases have in common the formation of amyloid filaments rich in cross-β sheets. Cryo-electron microscopy now permits the visualization of amyloid assemblies at atomic resolution, ushering a wide range of structural studies on several of these poorly understood amyloidogenic proteins. Amyloids are polymorphic with minor modulations in reaction environment affecting the overall architecture of their assembly, making amyloids an extremely challenging venture for structure-based therapeutic intervention. In 2017, the first cryo-EM structure of tau filaments from an Alzheimer's disease-affected brain established that in vitro assemblies might not necessarily reflect the native amyloid fold. Since then, brain-derived amyloid structures for several proteins across many neurodegenerative diseases have uncovered the disease-relevant amyloid folds. It has now been shown for tauopathies, synucleinopathies and TDP-43 proteinopathies, that distinct amyloid folds of the same protein might be related to different diseases. Salient features of each of these brain-derived folds are discussed in detail. It was also recently observed that seeded aggregation does not necessarily replicate the brain-derived structural fold. Owing to high throughput structure determination, some of these native amyloid folds have also been successfully replicated in vitro. In vitro replication of disease-relevant filaments will aid development of imaging ligands and defibrillating drugs. Towards this direction, recent high-resolution structures of tau filaments with positron emission tomography tracers and a defibrillating drug are also discussed. This review summarizes and celebrates the recent advancements in structural understanding of neuropathological amyloid filaments using cryo-EM.
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Affiliation(s)
- Suman Mishra
- Molecular Biophysics Unit, Biological Sciences Division, Indian Institute of Science, Bengaluru 560 012, Karnataka, India.
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8
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Smith MS, Knight IS, Kormos RC, Pepe JG, Kunach P, Diamond MI, Shahmoradian SH, Irwin JJ, DeGrado WF, Shoichet BK. Docking for molecules that bind in a symmetric stack with SymDOCK. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.27.564400. [PMID: 37961414 PMCID: PMC10634874 DOI: 10.1101/2023.10.27.564400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Discovering ligands for amyloid fibrils, such as those formed by the tau protein, is an area of much current interest. In recent structures, ligands bind in stacks in the tau fibrils to reflect the rotational and translational symmetry of the fibril itself; in these structures the ligands make few interactions with the protein but interact extensively with each other. To exploit this symmetry and stacking, we developed SymDOCK, a method to dock molecules that follow the protein's symmetry. For each prospective ligand pose, we apply the symmetry operation of the fibril to generate a self-interacting and fibril-interacting stack, checking that doing so will not cause a clash between the original molecule and its image. Absent a clash, we retain that pose and add the ligand-ligand van der Waals energy to the ligand's docking score (here using DOCK3.8). We can check these geometries and energies using an implementation of ANI, a neural network-based quantum-mechanical evaluation of the ligand stacking energies. In retrospective calculations, symmetry docking can reproduce the poses of three tau PET tracers whose structures have been determined. More convincingly, in a prospective study SymDOCK predicted the structure of the PET tracer MK-6240 bound in a symmetrical stack to AD PHF tau before that structure was determined; the docked pose was used to determine how MK-6240 fit the cryo-EM density. In proof-of-concept studies, SymDOCK enriched known ligands over property-matched decoys in retrospective screens without sacrificing docking speed, and can address large library screens that seek new symmetrical stackers. Future applications of this approach will be considered.
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Affiliation(s)
- Matthew S. Smith
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Program in Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Ian S. Knight
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Rian C. Kormos
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Program in Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Joseph G. Pepe
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Program in Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Peter Kunach
- McGill Research Centre for Studies in Aging, McGill University, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Marc I. Diamond
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sarah H. Shahmoradian
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John J. Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
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9
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Monteiro C, Toth B, Brunstein F, Bobbala A, Datta S, Ceniceros R, Sanabria Bohorquez SM, Anania VG, Wildsmith KR, Schauer SP, Lee J, Dolton MJ, Ramakrishnan V, Abramzon D, Teng E. Randomized Phase II Study of the Safety and Efficacy of Semorinemab in Participants With Mild-to-Moderate Alzheimer Disease: Lauriet. Neurology 2023; 101:e1391-e1401. [PMID: 37643887 PMCID: PMC10573141 DOI: 10.1212/wnl.0000000000207663] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/02/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Accumulation of tau pathology in Alzheimer disease (AD) correlates with cognitive decline. Anti-tau immunotherapies were proposed as potential interventions in AD. While antibodies targeting N-terminal tau failed to demonstrate clinical efficacy in prodromal-to-mild AD, their utility at other disease stages was not evaluated in prior studies. Lauriet is a phase 2 study of an anti-tau monoclonal antibody, semorinemab, in patients with mild-to-moderate AD. METHODS The phase 2 Lauriet study included a randomized, placebo-controlled, double-blind period, during which participants with mild-to-moderate AD received 4,500 mg of IV semorinemab or placebo every 4 weeks for 48 or 60 weeks. Participants who chose to continue in the subsequent optional open-label extension received 4,500 mg of semorinemab every 4 weeks for up to 96 weeks. Coprimary efficacy endpoints were change from baseline to week 49 or 61 on the 11-item version of the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog11) and the Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale. Secondary efficacy endpoints included change from baseline on the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating-Sum of Boxes (CDR-SB). Safety, pharmacokinetics, and pharmacodynamic effects were also evaluated. RESULTS Between December 3, 2018, and February 27, 2020, 624 individuals were screened, 272 participants were randomized, and 238 were included in the modified intent-to-treat population (received ≥1 dose(s) of study medication and underwent baseline and ≥1 postbaseline assessment(s)). Baseline characteristics were well balanced. At week 49, the semorinemab arm demonstrated a 42.2% reduction (-2.89 points, 95% CI -4.56 to -1.21, p = 0.0008) in decline on the ADAS-Cog11 (coprimary endpoint) relative to the placebo arm. However, no treatment effects were observed on the ADCS-ADL scale (coprimary endpoint; absolute difference between the 2 treatment arms in the ADCS-ADL score change from baseline of -0.83 points, 95% CI -3.39 to 1.72, p = 0.52) or on the MMSE or CDR-SB (secondary endpoints). Semorinemab was safe and well tolerated. DISCUSSION Based on the results of the prespecified coprimary endpoints, this study was negative. While semorinemab had a significant effect on cognition measured by the ADAS-Cog11, this effect did not extend to improved functional or global outcomes. These results may warrant further exploration of semorinemab or other anti-tau therapies in mild-to-moderate AD. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that semorinemab does not slow functional decline in patients with mild-to-moderate AD. TRIAL REGISTRATION INFORMATION The Lauriet study is registered on ClinicalTrials.gov, NCT03828747, and EudraCT 2018-003398-87.
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Affiliation(s)
| | - Balazs Toth
- From Genentech, Inc., South San Francisco, CA
| | | | | | - Seema Datta
- From Genentech, Inc., South San Francisco, CA
| | | | | | | | | | | | - Julie Lee
- From Genentech, Inc., South San Francisco, CA
| | | | | | | | - Edmond Teng
- From Genentech, Inc., South San Francisco, CA
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10
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Kunach P, Vaquer-Alicea J, Smith MS, Hopewell R, Monistrol J, Moquin L, Therriault J, Tissot C, Rahmouni N, Massarweh G, Soucy JP, Guiot MC, Shoichet BK, Rosa-Neto P, Diamond MI, Shahmoradian SH. Cryo-EM structure of Alzheimer's disease tau filaments with PET ligand MK-6240. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.558671. [PMID: 37790438 PMCID: PMC10542181 DOI: 10.1101/2023.09.22.558671] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Positron Emission Tomography (PET) ligands have advanced Alzheimer's disease (AD) diagnosis and treatment. Using autoradiography and cryo-EM, we identified AD brain tissue with elevated tau burden, purified filaments, and determined the structure of second-generation high avidity PET ligand MK-6240 at 2.31 Å resolution, which bound at a 1:1 ratio within the cleft of tau paired-helical filament (PHF), engaging with glutamine 351, lysine K353, and isoleucine 360. This information elucidates the basis of MK-6240 PET in quantifying PHF deposits in AD and may facilitate the structure-based design of superior ligands against tau amyloids.
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Affiliation(s)
- Peter Kunach
- Department of Neurology, McGill University, Montreal, Quebec, Canada
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, Dallas, TX, United States
| | - Jaime Vaquer-Alicea
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, Dallas, TX, United States
| | - Matthew S. Smith
- Department of Pharmaceutical Chemistry, UCSF, San Francisco, CA, United States
- Program of Biophysics, UCSF, San Francisco, CA, United States
| | | | - Jim Monistrol
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, Dallas, TX, United States
| | - Luc Moquin
- Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Joseph Therriault
- Department of Neurology, McGill University, Montreal, Quebec, Canada
| | - Cecile Tissot
- Department of Neurology, McGill University, Montreal, Quebec, Canada
| | - Nesrine Rahmouni
- Department of Neurology, McGill University, Montreal, Quebec, Canada
| | | | | | - Marie-Christine Guiot
- Department of Neurology, McGill University, Montreal, Quebec, Canada
- Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, UCSF, San Francisco, CA, United States
| | - Pedro Rosa-Neto
- Department of Neurology, McGill University, Montreal, Quebec, Canada
| | - Marc I. Diamond
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, Dallas, TX, United States
| | - Sarah H. Shahmoradian
- Center for Alzheimer’s and Neurodegenerative Diseases, Peter O’Donnell Jr. Brain Institute, Dallas, TX, United States
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11
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Marik J, Rich S, Deshmukh G, Zhang D, Tinianow J, Cai J, Wong S, Bobba S, DeMent K, Liu N, Halladay J, Sanabria-Bohórquez S, Cheruzel L, Khojasteh C. GTP1 metabolic stability assessment: A study of the tau PET tracer [ 18F]GTP1. Nucl Med Biol 2023; 124-125:108386. [PMID: 37699300 DOI: 10.1016/j.nucmedbio.2023.108386] [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: 07/06/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/14/2023]
Abstract
Tau PET imaging using the tau specific PET tracer [18F]GTP1 has been and is part of therapeutic trials in Alzheimer's disease to monitor the accumulation of tau aggregates in the brain. Herein, we examined the metabolic processes of GTP1 and assessed the influence of smoking on its metabolism through in vitro assays. The tracer metabolic profile was assessed by incubating GTP1 with human liver microsomes (HLM) and human hepatocytes. Since smoking strongly stimulates the CYP1A2 enzyme activity, we incubated GTP1 with recombinant CYP1A2 to evaluate the role of the enzyme in tracer metabolism. It was found that GTP1 could form up to eleven oxidative metabolites with higher polarity than the parent. Only a small amount (2.6 % at 60 min) of a defluorinated metabolite was detected in HLM and human hepatocytes incubations highlighting the stability of GTP1 with respect to enzymatic defluorination. Moreover, the major GTP1 metabolites were not the product of CYP1A2 activity suggesting that smoking may not impact in vivo tracer metabolism and subsequently GTP1 brain kinetics.
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Affiliation(s)
- Jan Marik
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA.
| | - Sharyl Rich
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Gauri Deshmukh
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Donglu Zhang
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Jeff Tinianow
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Jingwei Cai
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Susan Wong
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Sudheer Bobba
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Kevin DeMent
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Ning Liu
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Jason Halladay
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Sandra Sanabria-Bohórquez
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Lionel Cheruzel
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
| | - Cyrus Khojasteh
- Genentech Research and Early Development (gRED), Genentech Inc., 1 DNA way, South San Francisco, CA 94080, USA
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12
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Cools R, Kerkhofs K, Leitao RCF, Bormans G. Preclinical Evaluation of Novel PET Probes for Dementia. Semin Nucl Med 2023; 53:599-629. [PMID: 37149435 DOI: 10.1053/j.semnuclmed.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/08/2023]
Abstract
The development of novel PET imaging agents that selectively bind specific dementia-related targets can contribute significantly to accurate, differential and early diagnosis of dementia causing diseases and support the development of therapeutic agents. Consequently, in recent years there has been a growing body of literature describing the development and evaluation of potential new promising PET tracers for dementia. This review article provides a comprehensive overview of novel dementia PET probes under development, classified by their target, and pinpoints their preclinical evaluation pathway, typically involving in silico, in vitro and ex/in vivo evaluation. Specific target-associated challenges and pitfalls, requiring extensive and well-designed preclinical experimental evaluation assays to enable successful clinical translation and avoid shortcomings observed for previously developed 'well-established' dementia PET tracers are highlighted in this review.
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Affiliation(s)
- Romy Cools
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Kobe Kerkhofs
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; NURA, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Renan C F Leitao
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
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13
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Wagatsuma K, Miwa K, Akamatsu G, Yamao T, Kamitaka Y, Sakurai M, Fujita N, Hanaoka K, Matsuda H, Ishii K. Toward standardization of tau PET imaging corresponding to various tau PET tracers: a multicenter phantom study. Ann Nucl Med 2023; 37:494-503. [PMID: 37243882 DOI: 10.1007/s12149-023-01847-8] [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: 03/20/2023] [Accepted: 05/17/2023] [Indexed: 05/29/2023]
Abstract
OBJECTIVE Tau positron emission tomography (PET) imaging is a recently developed non-invasive tool that can detect the density and extension of tau neurofibrillary tangles. Tau PET tracers have been validated to harmonize and accelerate their development and implementation in clinical practice. Whereas standard protocols including injected dose, uptake time, and duration have been determined for tau PET tracers, reconstruction parameters have not been standardized. The present study conducted phantom experiments based on tau pathology to standardize quantitative tau PET imaging parameters and optimize reconstruction conditions of PET scanners at four Japanese sites according to the results of phantom experiments. METHODS The activity of 4.0 and 2.0 kBq/mL for Hoffman 3D brain and cylindrical phantoms, respectively, was estimated from published studies of brain activity using [18F]flortaucipir, [18F]THK5351, and [18F]MK6240. We developed an original tau-specific volume of interest template for the brain based on pathophysiological tau distribution in the brain defined as Braak stages. We acquired brain and cylindrical phantom images using four PET scanners. Iteration numbers were determined as contrast and recover coefficients (RCs) in gray (GM) and white (WM) matter, and the magnitude of the Gaussian filter was determined from image noise. RESULTS Contrast and RC converged at ≥ 4 iterations, the error rates of RC for GM and WM were < 15% and 1%, respectively, and noise was < 10% in Gaussian filters of 2-4 mm in images acquired using the four scanners. Optimizing the reconstruction conditions for phantom tau PET images acquired by each scanner improved contrast and image noise. CONCLUSIONS The phantom activity was comprehensive for first- and second-generation tau PET tracers. The mid-range activity that we determined could be applied to later tau PET tracers. We propose an analytical tau-specific VOI template based on tau pathophysiological changes in patients with AD to standardize tau PET imaging. Phantom images reconstructed under the optimized conditions for tau PET imaging achieved excellent image quality and quantitative accuracy.
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Affiliation(s)
- Kei Wagatsuma
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-Ku, Sagamihara, Kanagawa, 252-0373, Japan.
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2, Sakae-Cho, Itabashi-Ku, Tokyo, 173-0015, Japan.
| | - Kenta Miwa
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima City, Fukushima, 960-1295, Japan
| | - Go Akamatsu
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba, 263-8555, Japan
| | - Tensho Yamao
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima City, Fukushima, 960-1295, Japan
| | - Yuto Kamitaka
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2, Sakae-Cho, Itabashi-Ku, Tokyo, 173-0015, Japan
| | - Minoru Sakurai
- Clinical Imaging Center for Healthcare, Nippon Medical School, 1-12-15, Sendagi, Bunkyo-Ku, Tokyo, 113-0022, Japan
| | - Naotoshi Fujita
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-Cho, Showa-Ku, Nagoya, 466-8560, Japan
| | - Kohei Hanaoka
- Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Hiroshi Matsuda
- Department of Biofunctional Imaging, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, Fukushima, 960-1295, Japan
- Drug Discovery and Cyclotron Research Center, Southern Tohoku Research Institute for Neuroscience, 7-115, Yatsuyamada, Koriyama, 963-8052, Japan
| | - Kenji Ishii
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2, Sakae-Cho, Itabashi-Ku, Tokyo, 173-0015, Japan
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14
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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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15
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Nikiforova A, Sedov I. Molecular Design of Magnetic Resonance Imaging Agents Binding to Amyloid Deposits. Int J Mol Sci 2023; 24:11152. [PMID: 37446329 DOI: 10.3390/ijms241311152] [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: 06/12/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
The ability to detect and monitor amyloid deposition in the brain using non-invasive imaging techniques provides valuable insights into the early diagnosis and progression of Alzheimer's disease and helps to evaluate the efficacy of potential treatments. Magnetic resonance imaging (MRI) is a widely available technique offering high-spatial-resolution imaging. It can be used to visualize amyloid deposits with the help of amyloid-binding diagnostic agents injected into the body. In recent years, a number of amyloid-targeted MRI probes have been developed, but none of them has entered clinical practice. We review the advances in the field and deduce the requirements for the molecular structure and properties of a diagnostic probe candidate. These requirements make up the base for the rational design of MRI-active small molecules targeting amyloid deposits. Particular attention is paid to the novel cryo-EM structures of the fibril aggregates and their complexes, with known binders offering the possibility to use computational structure-based design methods. With continued research and development, MRI probes may revolutionize the diagnosis and treatment of neurodegenerative diseases, ultimately improving the lives of millions of people worldwide.
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Affiliation(s)
- Alena Nikiforova
- Chemical Institute, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Russia
| | - Igor Sedov
- Chemical Institute, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Russia
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16
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Villemagne VL, Leuzy A, Bohorquez SS, Bullich S, Shimada H, Rowe CC, Bourgeat P, Lopresti B, Huang K, Krishnadas N, Fripp J, Takado Y, Gogola A, Minhas D, Weimer R, Higuchi M, Stephens A, Hansson O, Doré V. CenTauR: Toward a universal scale and masks for standardizing tau imaging studies. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2023; 15:e12454. [PMID: 37424964 PMCID: PMC10326476 DOI: 10.1002/dad2.12454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/26/2023] [Accepted: 05/26/2023] [Indexed: 07/11/2023]
Abstract
INTRODUCTION Recently, an increasing number of tau tracers have become available. There is a need to standardize quantitative tau measures across tracers, supporting a universal scale. We developed several cortical tau masks and applied them to generate a tau imaging universal scale. METHOD One thousand forty-five participants underwent tau scans with either 18F-flortaucipir, 18F-MK6240, 18F-PI2620, 18F-PM-PBB3, 18F-GTP1, or 18F-RO948. The universal mask was generated from cognitively unimpaired amyloid beta (Aβ)- subjects and Alzheimer's disease (AD) patients with Aβ+. Four additional regional cortical masks were defined within the constraints of the universal mask. A universal scale, the CenTauRz, was constructed. RESULTS None of the regions known to display off-target signal were included in the masks. The CenTauRz allows robust discrimination between low and high levels of tau deposits. DISCUSSION We constructed several tau-specific cortical masks for the AD continuum and a universal standard scale designed to capture the location and degree of abnormality that can be applied across tracers and across centers. The masks are freely available at https://www.gaain.org/centaur-project.
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Affiliation(s)
- Victor L. Villemagne
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
- Department of Molecular Imaging & TherapyAustin HealthMelbourneVictoriaAustralia
| | - Antoine Leuzy
- Clinical Memory Research UnitDepartment of Clinical SciencesLund UniversityMalmöSweden
| | | | | | - Hitoshi Shimada
- Department of Functional Brain ImagingNational Institutes for Quantum and Radiological Science and TechnologyChibaJapan
- Brain Research InstituteNiigata UniversityNiigataJapan
| | - Christopher C. Rowe
- Department of Molecular Imaging & TherapyAustin HealthMelbourneVictoriaAustralia
- Florey Department of Neurosciences & Mental HealthThe University of MelbourneMelbourneParkvilleAustralia
- The Australian Dementia Network (ADNeT)MelbourneVictoriaAustralia
| | - Pierrick Bourgeat
- Health and Biosecurity FlagshipThe Australian eHealth Research CentreCSIROBrisbaneQueenslandAustralia
| | - Brian Lopresti
- Department of RadiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Kun Huang
- Department of Molecular Imaging & TherapyAustin HealthMelbourneVictoriaAustralia
| | - Natasha Krishnadas
- Department of Molecular Imaging & TherapyAustin HealthMelbourneVictoriaAustralia
- Florey Institute of Neurosciences & Mental HealthParkvilleVictoriaAustralia
| | - Jurgen Fripp
- Health and Biosecurity FlagshipThe Australian eHealth Research CentreCSIROBrisbaneQueenslandAustralia
| | - Yuhei Takado
- Department of Functional Brain ImagingNational Institutes for Quantum and Radiological Science and TechnologyChibaJapan
| | - Alexandra Gogola
- Department of RadiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Davneet Minhas
- Department of RadiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | | | - Makoto Higuchi
- Department of Functional Brain ImagingNational Institutes for Quantum and Radiological Science and TechnologyChibaJapan
| | | | - Oskar Hansson
- Clinical Memory Research UnitDepartment of Clinical SciencesLund UniversityMalmöSweden
- Memory ClinicSkåne University HospitalMalmöSweden
| | - Vincent Doré
- Department of Molecular Imaging & TherapyAustin HealthMelbourneVictoriaAustralia
- Health and Biosecurity FlagshipThe Australian eHealth Research CentreCSIROHeidelbergVictoriaAustralia
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Leuzy A, Binette AP, Vogel JW, Klein G, Borroni E, Tonietto M, Strandberg O, Mattsson-Carlgren N, Palmqvist S, Pontecorvo MJ, Iaccarino L, Stomrud E, Ossenkoppele R, Smith R, Hansson O. Comparison of Group-Level and Individualized Brain Regions for Measuring Change in Longitudinal Tau Positron Emission Tomography in Alzheimer Disease. JAMA Neurol 2023; 80:614-623. [PMID: 37155176 PMCID: PMC10167602 DOI: 10.1001/jamaneurol.2023.1067] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/15/2023] [Indexed: 05/10/2023]
Abstract
Importance Longitudinal tau positron emission tomography (PET) is a relevant outcome in clinical trials evaluating disease-modifying therapies in Alzheimer disease (AD). A key unanswered question is whether the use of participant-specific (individualized) regions of interest (ROIs) is superior to conventional approaches where the same ROI (group-level) is used for each participant. Objective To compare group- and participant-level ROIs in participants at different stages of the AD clinical continuum in terms of annual percentage change in tau-PET standardized uptake value ratio (SUVR) and sample size requirements. Design, Setting, and Participants This was a longitudinal cohort study with consecutive participant enrollment between September 18, 2017, and November 15, 2021. Included in the analysis were participants with mild cognitive impairment and AD dementia from the prospective and longitudinal Swedish Biomarkers For Identifying Neurodegenerative Disorders Early and Reliably 2 (BioFINDER-2) study; in addition, a validation sample (the AVID 05e, Expedition-3, Alzheimer's Disease Neuroimaging Initiative [ADNI], and BioFINDER-1 study cohorts) was also included. Exposures Tau PET (BioFINDER-2, [18F]RO948; validation sample, [18F]flortaucipir), 7 group-level (5 data-driven stages, meta-temporal, whole brain), and 5 individualized ROIs. Main Outcomes and Measures Annual percentage change in tau-PET SUVR across ROIs. Sample size requirements in simulated clinical trials using tau PET as an outcome were also calculated. Results A total of 215 participants (mean [SD] age, 71.4 (7.5) years; 111 male [51.6%]) from the BioFINDER-2 study were included in this analysis: 97 amyloid-β (Aβ)-positive cognitively unimpaired (CU) individuals, 77 with Aβ-positive mild cognitive impairment (MCI), and 41 with AD dementia. In the validation sample were 137 Aβ-positive CU participants, 144 with Aβ-positive MCI, and 125 with AD dementia. Mean (SD) follow-up time was 1.8 (0.3) years. Using group-level ROIs, the largest annual percentage increase in tau-PET SUVR in Aβ-positive CU individuals was seen in a composite ROI combining the entorhinal cortex, hippocampus, and amygdala (4.29%; 95% CI, 3.42%-5.16%). In individuals with Aβ-positive MCI, the greatest change was seen in the temporal cortical regions (5.82%; 95% CI, 4.67%-6.97%), whereas in those with AD dementia, the greatest change was seen in the parietal regions (5.22%; 95% CI, 3.95%-6.49%). Significantly higher estimates of annual percentage change were found using several of the participant-specific ROIs. Importantly, the simplest participant-specific approach, where change in tau PET was calculated in an ROI that best matched the participant's data-driven disease stage, performed best in all 3 subgroups. For the power analysis, sample size reductions for the participant-specific ROIs ranged from 15.94% (95% CI, 8.14%-23.74%) to 72.10% (95% CI, 67.10%-77.20%) compared with the best-performing group-level ROIs. Findings were replicated using [18F]flortaucipir. Conclusions and Relevance Finding suggest that certain individualized ROIs carry an advantage over group-level ROIs for assessing longitudinal tau changes and increase the power to detect treatment effects in AD clinical trials using longitudinal tau PET as an outcome.
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Affiliation(s)
- Antoine Leuzy
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Alexa Pichet Binette
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Jacob W. Vogel
- Penn/CHOP Lifespan Brain Institute, University of Pennsylvania, Philadelphia
- Department of Psychiatry, University of Pennsylvania, Philadelphia
| | | | | | | | - Olof Strandberg
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Niklas Mattsson-Carlgren
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Department of Neurology, Skåne University Hospital, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Sebastian Palmqvist
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Memory Clinic, Skåne University Hospital, Lund, Sweden
| | - Michael J. Pontecorvo
- Avid Radiopharmaceuticals, Philadelphia, Pennsylvania
- Eli Lilly and Company, Indianapolis, Indiana
| | - Leonardo Iaccarino
- Avid Radiopharmaceuticals, Philadelphia, Pennsylvania
- Eli Lilly and Company, Indianapolis, Indiana
| | - Erik Stomrud
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Memory Clinic, Skåne University Hospital, Lund, Sweden
| | - Rik Ossenkoppele
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC location VUmc, Amsterdam, the Netherlands
- Amsterdam Neuroscience, Neurodegeneration, Amsterdam, the Netherlands
| | - Ruben Smith
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Department of Neurology, Skåne University Hospital, Lund, Sweden
| | - Oskar Hansson
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Memory Clinic, Skåne University Hospital, Lund, Sweden
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18
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Merz GE, Chalkley MJ, Tan SK, Tse E, Lee J, Prusiner SB, Paras NA, DeGrado WF, Southworth DR. Stacked binding of a PET ligand to Alzheimer's tau paired helical filaments. Nat Commun 2023; 14:3048. [PMID: 37236970 PMCID: PMC10220082 DOI: 10.1038/s41467-023-38537-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
Accumulation of filamentous aggregates of tau protein in the brain is a pathological hallmark of Alzheimer's disease (AD) and many other neurodegenerative tauopathies. The filaments adopt disease-specific cross-β amyloid conformations that self-propagate and are implicated in neuronal loss. Development of molecular diagnostics and therapeutics is of critical importance. However, mechanisms of small molecule binding to the amyloid core is poorly understood. We used cryo-electron microscopy to determine a 2.7 Å structure of AD patient-derived tau paired-helical filaments bound to the PET ligand GTP-1. The compound is bound stoichiometrically at a single site along an exposed cleft of each protofilament in a stacked arrangement matching the fibril symmetry. Multiscale modeling reveals pi-pi aromatic interactions that pair favorably with the small molecule-protein contacts, supporting high specificity and affinity for the AD tau conformation. This binding mode offers critical insight into designing compounds to target different amyloid folds found across neurodegenerative diseases.
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Affiliation(s)
- Gregory E Merz
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Matthew J Chalkley
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Sophia K Tan
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Eric Tse
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
| | - Joanne Lee
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Nick A Paras
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - William F DeGrado
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Daniel R Southworth
- Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA.
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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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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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21
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Loftus JR, Puri S, Meyers SP. Multimodality imaging of neurodegenerative disorders with a focus on multiparametric magnetic resonance and molecular imaging. Insights Imaging 2023; 14:8. [PMID: 36645560 PMCID: PMC9842851 DOI: 10.1186/s13244-022-01358-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 12/13/2022] [Indexed: 01/17/2023] Open
Abstract
Neurodegenerative diseases afflict a large number of persons worldwide, with the prevalence and incidence of dementia rapidly increasing. Despite their prevalence, clinical diagnosis of dementia syndromes remains imperfect with limited specificity. Conventional structural-based imaging techniques also lack the accuracy necessary for confident diagnosis. Multiparametric magnetic resonance imaging and molecular imaging provide the promise of improving specificity and sensitivity in the diagnosis of neurodegenerative disease as well as therapeutic monitoring of monoclonal antibody therapy. This educational review will briefly focus on the epidemiology, clinical presentation, and pathologic findings of common and uncommon neurodegenerative diseases. Imaging features of each disease spanning from conventional magnetic resonance sequences to advanced multiparametric methods such as resting-state functional magnetic resonance imaging and arterial spin labeling imaging will be described in detail. Additionally, the review will explore the findings of each diagnosis on molecular imaging including single-photon emission computed tomography and positron emission tomography with a variety of clinically used and experimental radiotracers. The literature and clinical cases provided demonstrate the power of advanced magnetic resonance imaging and molecular techniques in the diagnosis of neurodegenerative diseases and areas of future and ongoing research. With the advent of combined positron emission tomography/magnetic resonance imaging scanners, hybrid protocols utilizing both techniques are an attractive option for improving the evaluation of neurodegenerative diseases.
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Affiliation(s)
- James Ryan Loftus
- grid.412750.50000 0004 1936 9166Department of Imaging Sciences, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642 USA
| | - Savita Puri
- grid.412750.50000 0004 1936 9166Department of Imaging Sciences, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642 USA
| | - Steven P. Meyers
- grid.412750.50000 0004 1936 9166Department of Imaging Sciences, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642 USA
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22
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Bullich S, Mueller A, De Santi S, Koglin N, Krause S, Kaplow J, Kanekiyo M, Roé-Vellvé N, Perrotin A, Jovalekic A, Scott D, Gee M, Stephens A, Irizarry M. Evaluation of tau deposition using 18F-PI-2620 PET in MCI and early AD subjects—a MissionAD tau sub-study. Alzheimers Res Ther 2022; 14:105. [PMID: 35897078 PMCID: PMC9327167 DOI: 10.1186/s13195-022-01048-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/11/2022] [Indexed: 11/10/2022]
Abstract
Background The ability of 18F-PI-2620 PET to measure the spatial distribution of tau pathology in Alzheimer’s disease (AD) has been demonstrated in previous studies. The objective of this work was to evaluate tau deposition using 18F-PI-2620 PET in beta-amyloid positive subjects with a diagnosis of mild cognitive impairment (MCI) or mild AD dementia and characterize it with respect to amyloid deposition, cerebrospinal fluid (CSF) assessment, hippocampal volume, and cognition. Methods Subjects with a diagnosis of MCI due to AD or mild AD dementia and a visually amyloid-positive 18F-florbetaben PET scan (n=74, 76 ± 7 years, 38 females) underwent a baseline 18F-PI-2620 PET, T1-weighted magnetic resonance imaging (MRI), CSF assessment (Aβ42/Aβ40 ratio, p-tau, t-tau) (n=22) and several cognitive tests. A 1-year follow-up 18F-PI-2620 PET scans and cognitive assessments were done in 15 subjects. Results Percentage of visually tau-positive scans increased with amyloid-beta deposition measured in 18F-florbetaben Centiloids (CL) (7.7% (<36 CL), 80% (>83 CL)). 18F-PI-2620 standardized uptake value ratio (SUVR) was correlated with increased 18F-florbetaben CL in several regions of interest. Elevated 18F-PI-2620 SUVR (fusiform gyrus) was associated to high CSF p-tau and t-tau (p=0.0006 and p=0.01, respectively). Low hippocampal volume was associated with increased tau load at baseline (p=0.006 (mesial temporal); p=0.01 (fusiform gyrus)). Significant increases in tau SUVR were observed after 12 months, particularly in the mesial temporal cortex, fusiform gyrus, and inferior temporal cortex (p=0.04, p=0.047, p=0.02, respectively). However, no statistically significant increase in amyloid-beta load was measured over the observation time. The MMSE (Recall score), ADAS-Cog14 (Word recognition score), and CBB (One-card learning score) showed the strongest association with tau deposition at baseline. Conclusions The findings support the hypothesis that 18F-PI-2620 PET imaging of neuropathologic tau deposits may reflect underlying neurodegeneration in AD with significant correlations with hippocampal volume, CSF biomarkers, and amyloid-beta load. Furthermore, quantifiable increases in 18F-PI-2620 SUVR over a 12-month period in regions with early tau deposition are consistent with the hypothesis that cortical tau is associated with cognitive impairment. This study supports the utility of 18F-PI-2620 PET to assess tau deposits in an early AD population. Quantifiable tau load and its corresponding increase in early AD cases could be a relevant target engagement marker in clinical trials of anti-amyloid and anti-tau agents. Trial registration Data used in this manuscript belong to a tau PET imaging sub-study of the elenbecestat MissionAD Phase 3 program registered in ClinicalTrials.gov (NCT02956486; NCT03036280). Supplementary Information The online version contains supplementary material available at 10.1186/s13195-022-01048-x.
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23
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Ramesh M, Govindaraju T. Multipronged diagnostic and therapeutic strategies for Alzheimer's disease. Chem Sci 2022; 13:13657-13689. [PMID: 36544728 PMCID: PMC9710308 DOI: 10.1039/d2sc03932j] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/13/2022] [Indexed: 12/24/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and a major contributor to dementia cases worldwide. AD is clinically characterized by learning, memory, and cognitive deficits. The accumulation of extracellular amyloid β (Aβ) plaques and neurofibrillary tangles (NFTs) of tau are the pathological hallmarks of AD and are explored as targets for clinical diagnosis and therapy. AD pathology is poorly understood and there are no fully approved diagnosis and treatments. Notwithstanding the gap, decades of research in understanding disease mechanisms have revealed the multifactorial nature of AD. As a result, multipronged and holistic approaches are pertinent to targeting multiple biomarkers and targets for developing effective diagnosis and therapeutics. In this perspective, recent developments in Aβ and tau targeted diagnostic and therapeutic tools are discussed. Novel indirect, combination, and circulating biomarkers as potential diagnostic targets are highlighted. We underline the importance of multiplexing and multimodal detection of multiple biomarkers to generate biomarker fingerprints as a reliable diagnostic strategy. The classical therapeutics targeting Aβ and tau aggregation pathways are described with bottlenecks in the strategy. Drug discovery efforts targeting multifaceted toxicity involving protein aggregation, metal toxicity, oxidative stress, mitochondrial damage, and neuroinflammation are highlighted. Recent efforts focused on multipronged strategies to rationally design multifunctional modulators targeting multiple pathological factors are presented as future drug development strategies to discover potential therapeutics for AD.
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Affiliation(s)
- Madhu Ramesh
- Bioorganic Chemistry Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur P.O. Bengaluru Karnataka 560064 India
| | - Thimmaiah Govindaraju
- Bioorganic Chemistry Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur P.O. Bengaluru Karnataka 560064 India
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24
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Endo H, Tagai K, Ono M, Ikoma Y, Oyama A, Matsuoka K, Kokubo N, Hirata K, Sano Y, Oya M, Matsumoto H, Kurose S, Seki C, Shimizu H, Kakita A, Takahata K, Shinotoh H, Shimada H, Tokuda T, Kawamura K, Zhang M, Oishi K, Mori S, Takado Y, Higuchi M. A Machine Learning-Based Approach to Discrimination of Tauopathies Using [ 18 F]PM-PBB3 PET Images. Mov Disord 2022; 37:2236-2246. [PMID: 36054492 PMCID: PMC9805085 DOI: 10.1002/mds.29173] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/03/2022] [Accepted: 07/10/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND We recently developed a positron emission tomography (PET) probe, [18 F]PM-PBB3, to detect tau lesions in diverse tauopathies, including mixed three-repeat and four-repeat (3R + 4R) tau fibrils in Alzheimer's disease (AD) and 4R tau aggregates in progressive supranuclear palsy (PSP). For wider availability of this technology for clinical settings, bias-free quantitative evaluation of tau images without a priori disease information is needed. OBJECTIVE We aimed to establish tau PET pathology indices to characterize PSP and AD using a machine learning approach and test their validity and tracer capabilities. METHODS Data were obtained from 50 healthy control subjects, 46 patients with PSP Richardson syndrome, and 37 patients on the AD continuum. Tau PET data from 114 regions of interest were subjected to Elastic Net cross-validation linear classification analysis with a one-versus-the-rest multiclass strategy to obtain a linear function that discriminates diseases by maximizing the area under the receiver operating characteristic curve. We defined PSP- and AD-tau scores for each participant as values of the functions optimized for differentiating PSP (4R) and AD (3R + 4R), respectively, from others. RESULTS The discriminatory ability of PSP- and AD-tau scores assessed as the area under the receiver operating characteristic curve was 0.98 and 1.00, respectively. PSP-tau scores correlated with the PSP rating scale in patients with PSP, and AD-tau scores correlated with Mini-Mental State Examination scores in healthy control-AD continuum patients. The globus pallidus and amygdala were highlighted as regions with high weight coefficients for determining PSP- and AD-tau scores, respectively. CONCLUSIONS These findings highlight our technology's unbiased capability to identify topologies of 3R + 4R versus 4R tau deposits. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Hironobu Endo
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Kenji Tagai
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Maiko Ono
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Yoko Ikoma
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Asaka Oyama
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Kiwamu Matsuoka
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Naomi Kokubo
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Kosei Hirata
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Yasunori Sano
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Masaki Oya
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Hideki Matsumoto
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan,Department of Oral and Maxillofacial RadiologyTokyo Dental CollegeTokyoJapan
| | - Shin Kurose
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Chie Seki
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Hiroshi Shimizu
- Department of Pathology, Brain Research InstituteNiigata UniversityNiigataJapan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research InstituteNiigata UniversityNiigataJapan
| | - Keisuke Takahata
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | | | - Hitoshi Shimada
- Department of Functional Neurology & Neurosurgery, Center for Integrated Human Brain Science, Brain Research InstituteNiigata UniversityNiigataJapan
| | - Takahiko Tokuda
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Kazunori Kawamura
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Ming‐Rong Zhang
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Kenichi Oishi
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Susumu Mori
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Yuhei Takado
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
| | - Makoto Higuchi
- Institute for Quantum Medical Science, Quantum Life and Medical Science DirectorateNational Institutes for Quantum Science and TechnologyChibaJapan
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25
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Kallinen A, Kassiou M. Tracer development for PET imaging of proteinopathies. Nucl Med Biol 2022; 114-115:108-120. [PMID: 35487833 DOI: 10.1016/j.nucmedbio.2022.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/17/2022] [Accepted: 04/04/2022] [Indexed: 12/27/2022]
Abstract
This review outlines small molecule radiotracers developed for positron emission tomography (PET) imaging of proteinopathies, neurodegenerative diseases characterised by accumulation of malformed proteins, over the last two decades with the focus on radioligands that have progressed to clinical studies. Introduction provides a short summary of proteinopathy targets used for PET imaging, including vastly studied proteins Aβ and tau and emerging α-synuclein. In the main section, clinically relevant Aβ and tau radioligand classes and their properties are discussed, including an overview of lead compounds and radioligand candidates studied as α-synuclein imaging agents in the early discovery and preclinical development phase. Lastly, the specific challenges and future directions in proteinopathy radioligand development are summarized.
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Affiliation(s)
- Annukka Kallinen
- Garvan Institute of Medical Research, 384 Victoria St, NSW 2010, Australia.
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, NSW 2006, Australia
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26
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Knight AC, Morrone CD, Varlow C, Yu WH, McQuade P, Vasdev N. Head-to-Head Comparison of Tau-PET Radioligands for Imaging TDP-43 in Post-Mortem ALS Brain. Mol Imaging Biol 2022; 25:513-527. [PMID: 36258099 DOI: 10.1007/s11307-022-01779-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE In vivo detection of transactivation response element DNA binding protein-43 kDa (TDP-43) aggregates through positron emission tomography (PET) would impact the ability to successfully develop therapeutic interventions for a variety of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). The purpose of the present study is to evaluate the ability of six tau PET radioligands to bind to TDP-43 aggregates in post-mortem brain tissues from ALS patients. PROCEDURES Herein, we report the first head-to-head evaluation of six tritium labeled isotopologs of tau-targeting PET radioligands, [3H]MK-6240 (a.k.a. florquinitau), [3H]Genentech Tau Probe-1 (GTP-1), [3H]JNJ-64326067(JNJ-067), [3H]CBD-2115, [3H]flortaucipir, and [3H]APN-1607, and their ability to bind to the β-pleated sheet structures of aggregate TDP-43 in post-mortem ALS brain tissues by autoradiography and immunostaining methods. Post-mortem frontal cortex, motor cortex, and cerebellum tissues were evaluated, and binding intensity was aligned with areas of elevated phosphorylated tau (ptau), pTDP-43, and β-amyloid. RESULTS Negligible binding was observed with [3H]MK-6240, [3H]JNJ-067, and [3H]GTP-1. While [3H]CBD-2115 displayed marginal specific binding, this binding did not significantly correlate with the distribution of pTDP-43 and AT8 inclusions. Of the remaining ligands, the distribution of [3H]flortaucipir did not significantly correlate to pTDP-43 pathology; however, specific binding trends to a positive relationship with tau. Finally, [3H]APN-1607 relates most strongly to amyloid load and does not indicate pTDP-43 pathology as confirmed by [3H]PiB distribution in sister sections. CONCLUSIONS Our results demonstrate the prominent nature of mixed pathology in ALS, and do not support the application of [3H]MK-6240, [3H]JNJ-067, [3H]GTP-1, [3H]CBD-2115, [3H]flortaucipir, or [3H]APN-1607 for selective imaging TDP-43 in ALS for clinical research with the currently available in vitro data. Identification of potent and selective radiotracers for TDP-43 remains an ongoing challenge.
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Affiliation(s)
- Ashley C Knight
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Canada
- Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, Canada
| | - Christopher D Morrone
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Canada
| | - Cassis Varlow
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Canada
- Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, Canada
| | - Wai Haung Yu
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Canada
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, Canada
| | - Paul McQuade
- Takeda Pharmaceutical Company, Ltd, 35 Landsdowne Street, Cambridge, MA, USA
| | - Neil Vasdev
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Canada.
- Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, Canada.
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Canada.
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27
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GC-CNNnet: Diagnosis of Alzheimer’s Disease with PET Images Using Genetic and Convolutional Neural Network. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2022; 2022:7413081. [PMID: 35983158 PMCID: PMC9381254 DOI: 10.1155/2022/7413081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 06/01/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022]
Abstract
There is a wide variety of effects of Alzheimer's disease (AD), a neurodegenerative disease that can lead to cognitive decline, deterioration of daily life, and behavioral and psychological changes. A polymorphism of the ApoE gene ε 4 is considered a genetic risk factor for Alzheimer's disease. The purpose of this paper is to demonstrate that single-nucleotide polymorphic markers (SNPs) have a causal relationship with quantitative PET imaging traits. Additionally, the classification of AD is based on the frequency of brain tissue variations in PET images using a combination of k-nearest-neighbor (KNN), support vector machine (SVM), linear discrimination analysis (LDA), and convolutional neural network (CNN) techniques. According to the results, the suggested SNPs appear to be associated with quantitative traits more strongly than the SNPs in the ApoE genes. Regarding the classification result, the highest accuracy is obtained by the CNN with 91.1%. These results indicate that the KNN and CNN methods are beneficial in diagnosing AD. Nevertheless, the LDA and SVM are demonstrated with a lower level of accuracy.
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Teng E, Manser PT, Pickthorn K, Brunstein F, Blendstrup M, Sanabria Bohorquez S, Wildsmith KR, Toth B, Dolton M, Ramakrishnan V, Bobbala A, Sikkes SAM, Ward M, Fuji RN, Kerchner GA. Safety and Efficacy of Semorinemab in Individuals With Prodromal to Mild Alzheimer Disease: A Randomized Clinical Trial. JAMA Neurol 2022; 79:758-767. [PMID: 35696185 PMCID: PMC9194753 DOI: 10.1001/jamaneurol.2022.1375] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/17/2022] [Indexed: 12/23/2022]
Abstract
Importance Neurofibrillary tangles composed of aggregated tau protein are one of the neuropathological hallmarks of Alzheimer disease (AD) and correlate with clinical disease severity. Monoclonal antibodies targeting tau may have the potential to ameliorate AD progression by slowing or stopping the spread and/or accumulation of pathological tau. Objective To evaluate the safety and efficacy of the monoclonal anti-tau antibody semorinemab in prodromal to mild AD. Design, Setting, and Participants This phase 2 randomized, double-blind, placebo-controlled, parallel-group clinical trial was conducted between October 18, 2017, and July 16, 2020, at 97 sites in North America, Europe, and Australia. Individuals aged 50 to 80 years (inclusive) with prodromal to mild AD, Mini-Mental State Examination scores between 20 and 30 (inclusive), and confirmed β-amyloid pathology (by positron emission tomography or cerebrospinal fluid) were included. Interventions During the 73-week blinded study period, participants received intravenous infusions of placebo or semorinemab (1500 mg, 4500 mg, or 8100 mg) every 2 weeks for the first 3 infusions and every 4 weeks thereafter. Main Outcomes and Measures The primary outcomes were change from baseline on the Clinical Dementia Rating-Sum of Boxes score from baseline to week 73 and assessments of the safety and tolerability for semorinemab compared with placebo. Results In the modified intent-to-treat cohort (n = 422; mean [SD] age, 69.6 [7.0] years; 235 women [55.7%]), similar increases were seen on the Clinical Dementia Rating-Sum of Boxes score in the placebo (n = 126; Δ = 2.19 [95% CI, 1.74-2.63]) and semorinemab (1500 mg: n = 86; Δ = 2.36 [95% CI, 1.83-2.89]; 4500 mg: n = 126; Δ = 2.36 [95% CI, 1.92-2.79]; 8100 mg: n = 84; Δ = 2.41 [95% CI, 1.88-2.94]) arms. In the safety-evaluable cohort (n = 441), similar proportions of participants experienced adverse events in the placebo (130 [93.1%]) and semorinemab (1500 mg: 89 [88.8%]; 4500 mg: 132 [94.7%]; 8100 mg: 90 [92.2%]) arms. Conclusions and Relevance In participants with prodromal to mild AD in this randomized clinical trial, semorinemab did not slow clinical AD progression compared with placebo throughout the 73-week study period but did demonstrate an acceptable and well-tolerated safety profile. Additional studies of anti-tau antibodies may be needed to determine the clinical utility of this therapeutic approach. Trial Registration ClinicalTrials.gov Identifier: NCT03289143.
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Affiliation(s)
- Edmond Teng
- Early Clinical Development, Genentech Inc, South San Francisco, California
| | - Paul T. Manser
- Biostatistics, Genentech Inc, South San Francisco, California
| | - Karen Pickthorn
- Early Clinical Development, Genentech Inc, South San Francisco, California
| | - Flavia Brunstein
- Product Development Safety, Genentech Inc, South San Francisco, California
| | - Mira Blendstrup
- Clinical Operations, Genentech Inc, South San Francisco, California
| | | | - Kristin R. Wildsmith
- Biomarker Development, Genentech Inc, South San Francisco, California
- Now with Eisai Inc, Woodcliff Lake, New Jersey
| | - Bali Toth
- Biostatistics, Genentech Inc, South San Francisco, California
| | | | | | - Ashwini Bobbala
- Product Development Safety, Genentech Inc, South San Francisco, California
| | - Sietske A. M. Sikkes
- Alzheimer Center Amsterdam, Amsterdam Neuroscience, Amsterdam University Medical Center, VU University Amsterdam, Amsterdam, the Netherlands
- Department of Clinical, Neuro- and Developmental Psychology, VU University, Amsterdam, the Netherlands
| | - Michael Ward
- Early Clinical Development, Genentech Inc, South San Francisco, California
- Now with Alector Inc, South San Francisco, California
| | - Reina N. Fuji
- Safety Assessment, Genentech Inc, South San Francisco, California
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Li Y, Liu T, Cui M. Recent development in selective Tau tracers for PET imaging in the brain. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.03.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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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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Maschio C, Ni R. Amyloid and Tau Positron Emission Tomography Imaging in Alzheimer’s Disease and Other Tauopathies. Front Aging Neurosci 2022; 14:838034. [PMID: 35527737 PMCID: PMC9074832 DOI: 10.3389/fnagi.2022.838034] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/24/2022] [Indexed: 12/11/2022] Open
Abstract
The detection and staging of Alzheimer’s disease (AD) using non-invasive imaging biomarkers is of substantial clinical importance. Positron emission tomography (PET) provides readouts to uncover molecular alterations in the brains of AD patients with high sensitivity and specificity. A variety of amyloid-β (Aβ) and tau PET tracers are already available for the clinical diagnosis of AD, but there is still a lack of imaging biomarkers with high affinity and selectivity for tau inclusions in primary tauopathies, such as progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Pick’s disease (PiD). This review aims to provide an overview of the existing Aβ and tau PET imaging biomarkers and their binding properties from in silico, in vitro, and in vivo assessment. Imaging biomarkers for pathologic proteins are vital for clinical diagnosis, disease staging and monitoring of the potential therapeutic approaches of AD. Off-target binding of radiolabeled tracers to white matter or other neural structures is one confounding factor when interpreting images. To improve binding properties such as binding affinity and to eliminate off-target binding, second generation of tau PET tracers have been developed. To conclude, we further provide an outlook for imaging tauopathies and other pathological features of AD and primary tauopathies.
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Affiliation(s)
- Cinzia Maschio
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- *Correspondence: Cinzia Maschio,
| | - Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, ETH Zürich and University of Zurich, Zurich, Switzerland
- Ruiqing Ni,
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Non-invasive imaging of tau-targeted probe uptake by whole brain multi-spectral optoacoustic tomography. Eur J Nucl Med Mol Imaging 2022; 49:2137-2152. [PMID: 35128565 PMCID: PMC9165274 DOI: 10.1007/s00259-022-05708-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/25/2022] [Indexed: 02/06/2023]
Abstract
Purpose Abnormal tau accumulation within the brain plays an important role in tauopathies such as Alzheimer’s disease and frontotemporal dementia. High-resolution imaging of tau deposits at the whole-brain scale in animal disease models is highly desired. Methods We approached this challenge by non-invasively imaging the brains of P301L mice of 4-repeat tau with concurrent volumetric multi-spectral optoacoustic tomography (vMSOT) at ~ 115 μm spatial resolution using the tau-targeted pyridinyl-butadienyl-benzothiazole derivative PBB5 (i.v.). In vitro probe characterization, concurrent vMSOT and epi-fluorescence imaging of in vivo PBB5 targeting (i.v.) was performed in P301L and wild-type mice, followed by ex vivo validation using AT-8 antibody for phosphorylated tau. Results PBB5 showed specific binding to recombinant K18 tau fibrils by fluorescence assay, to post-mortem Alzheimer’s disease brain tissue homogenate by competitive binding against [11C]PBB3 and to tau deposits (AT-8 positive) in post-mortem corticobasal degeneration and progressive supranuclear palsy brains. Dose-dependent optoacoustic and fluorescence signal intensities were observed in the mouse brains following i.v. administration of different concentrations of PBB5. In vivo vMSOT brain imaging of P301L mice showed higher retention of PBB5 in the tau-laden cortex and hippocampus compared to wild-type mice, as confirmed by ex vivo vMSOT, epi-fluorescence, multiphoton microscopy, and immunofluorescence staining. Conclusions We demonstrated non-invasive whole-brain imaging of tau in P301L mice with vMSOT system using PBB5 at a previously unachieved ~ 115 μm spatial resolution. This platform provides a new tool to study tau spreading and clearance in a tauopathy mouse model, foreseeable in monitoring tau targeting putative therapeutics. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-022-05708-w.
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Ni R, Nitsch RM. Recent Developments in Positron Emission Tomography Tracers for Proteinopathies Imaging in Dementia. Front Aging Neurosci 2022; 13:751897. [PMID: 35046791 PMCID: PMC8761855 DOI: 10.3389/fnagi.2021.751897] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/17/2021] [Indexed: 12/15/2022] Open
Abstract
An early detection and intervention for dementia represent tremendous unmet clinical needs and priorities in society. A shared feature of neurodegenerative diseases causing dementia is the abnormal accumulation and spreading of pathological protein aggregates, which affect the selective vulnerable circuit in a disease-specific pattern. The advancement in positron emission tomography (PET) biomarkers has accelerated the understanding of the disease mechanism and development of therapeutics for Alzheimer's disease and Parkinson's disease. The clinical utility of amyloid-β PET and the clinical validity of tau PET as diagnostic biomarker for Alzheimer's disease continuum have been demonstrated. The inclusion of biomarkers in the diagnostic criteria has introduced a paradigm shift that facilitated the early and differential disease diagnosis and impacted on the clinical management. Application of disease-modifying therapy likely requires screening of patients with molecular evidence of pathological accumulation and monitoring of treatment effect assisted with biomarkers. There is currently still a gap in specific 4-repeat tau imaging probes for 4-repeat tauopathies and α-synuclein imaging probes for Parkinson's disease and dementia with Lewy body. In this review, we focused on recent development in molecular imaging biomarkers for assisting the early diagnosis of proteinopathies (i.e., amyloid-β, tau, and α-synuclein) in dementia and discussed future perspectives.
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Affiliation(s)
- Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, ETH & University of Zurich, Zurich, Switzerland
| | - Roger M. Nitsch
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
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Jia H, Xie T. Tracers progress for positron emission tomography imaging of glial-related disease. J Biomed Res 2022; 36:321-335. [PMID: 36131689 PMCID: PMC9548440 DOI: 10.7555/jbr.36.20220017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Glial cells play an essential part in the neuron system. They can not only serve as structural blocks in the human brain but also participate in many biological processes. Extensive studies have shown that astrocytes and microglia play an important role in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, as well as glioma, epilepsy, ischemic stroke, and infections. Positron emission tomography is a functional imaging technique providing molecular-level information before anatomic changes are visible and has been widely used in many above-mentioned diseases. In this review, we focus on the positron emission tomography tracers used in pathologies related to glial cells, such as glioma, Alzheimer's disease, and neuroinflammation.
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Affiliation(s)
- Haoran Jia
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Tianwu Xie
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
- Tianwu Xie, Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China. Tel: +86-21-64048363, E-mail:
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36
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Brumberg J, Varrone A. New PET radiopharmaceuticals for imaging CNS diseases. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00002-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Teng E, Manser PT, Sanabria Bohorquez S, Wildsmith KR, Pickthorn K, Baker SL, Ward M, Kerchner GA, Weimer RM. Baseline [ 18F]GTP1 tau PET imaging is associated with subsequent cognitive decline in Alzheimer's disease. Alzheimers Res Ther 2021; 13:196. [PMID: 34852837 PMCID: PMC8638526 DOI: 10.1186/s13195-021-00937-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022]
Abstract
Background The role and implementation of tau PET imaging for predicting subsequent cognitive decline in Alzheimer’s disease (AD) remains uncertain. This study was designed to evaluate the relationship between baseline [18F]GTP1 tau PET and subsequent longitudinal change across multiple cognitive measures over 18 months. Methods Our analyses incorporated data from 67 participants, including cognitively normal controls (n = 10) and β-amyloid (Aβ)-positive individuals ([18F] florbetapir Aβ PET) with prodromal (n = 26), mild (n = 16), or moderate (n = 15) AD. Baseline measurements included cortical volume (MRI), tau burden ([18F]GTP1 tau PET), and cognitive assessments [Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), 13-item version of the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog13), and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)]. Cognitive assessments were repeated at 6-month intervals over an 18-month period. Associations between baseline [18F]GTP1 tau PET indices and longitudinal cognitive performance were assessed via univariate (Spearman correlations) and multivariate (linear mixed effects models) approaches. The utility of potential prognostic tau PET cut points was assessed with ROC curves. Results Univariate analyses indicated that greater baseline [18F]GTP1 tau PET signal was associated with faster rates of subsequent decline on the MMSE, CDR, and ADAS-Cog13 across regions of interest (ROIs). In multivariate analyses adjusted for baseline age, cognitive performance, cortical volume, and Aβ PET SUVR, the prognostic performance of [18F]GTP1 SUVR was most robust in the whole cortical gray ROI. When AD participants were dichotomized into low versus high tau subgroups based on baseline [18F]GTP1 PET standardized uptake value ratios (SUVR) in the temporal (cutoff = 1.325) or whole cortical gray (cutoff = 1.245) ROIs, high tau subgroups demonstrated significantly more decline on the MMSE, CDR, and ADAS-Cog13. Conclusions Our results suggest that [18F]GTP1 tau PET represents a prognostic biomarker in AD and are consistent with data from other tau PET tracers. Tau PET imaging may have utility for identifying AD patients at risk for more rapid cognitive decline and for stratification and/or enrichment of participant selection in AD clinical trials. Trial registration ClinicalTrials.gov NCT02640092. Registered on December 28, 2015 Supplementary Information The online version contains supplementary material available at 10.1186/s13195-021-00937-x.
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Affiliation(s)
- Edmond Teng
- Early Clinical Development, Genentech, Inc., South San Francisco, CA, USA.
| | - Paul T Manser
- Clinical Biostatistics, Genentech, Inc., South San Francisco, CA, USA
| | | | | | - Karen Pickthorn
- Early Clinical Development, Genentech, Inc., South San Francisco, CA, USA
| | - Suzanne L Baker
- Clinical Imaging Group, Genentech, Inc., South San Francisco, CA, USA.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Michael Ward
- Early Clinical Development, Genentech, Inc., South San Francisco, CA, USA.,Current Address: Alector, Inc., South San Francisco, CA, USA
| | - Geoffrey A Kerchner
- Early Clinical Development, Genentech, Inc., South San Francisco, CA, USA.,Current Address: F. Hoffmann-La Roche AG, Basel, Switzerland
| | - Robby M Weimer
- Biomedical Imaging, Genentech, Inc., South San Francisco, CA, USA
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38
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Baker SL, Provost K, Thomas W, Whitman AJ, Janabi M, Schmidt ME, Timmers M, Kolb HC, Rabinovici GD, Jagust WJ. Evaluation of [ 18F]-JNJ-64326067-AAA tau PET tracer in humans. J Cereb Blood Flow Metab 2021; 41:3302-3313. [PMID: 34259071 PMCID: PMC8669274 DOI: 10.1177/0271678x211031035] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The [18F]-JNJ-64326067-AAA ([18F]-JNJ-067) tau tracer was evaluated in healthy older controls (HCs), mild cognitive impairment (MCI), Alzheimer's disease (AD), and progressive supranuclear palsy (PSP) participants. Seventeen subjects (4 HCs, 5 MCIs, 5 ADs, and 3 PSPs) received a [11C]-PIB amyloid PET scan, and a tau [18F]-JNJ-067 PET scan 0-90 minutes post-injection. Only MCIs and ADs were amyloid positive. The simplified reference tissue model, Logan graphical analysis distribution volume ratio, and SUVR were evaluated for quantification. The [18F]-JNJ-067 tau signal relative to the reference region continued to increase to 90 min, indicating the tracer had not reached steady state. There was no significant difference in any bilateral ROIs for MCIs or PSPs relative to HCs; AD participants showed elevated tracer relative to controls in most cortical ROIs (P < 0.05). Only AD participants showed elevated retention in the entorhinal cortex. There was off-target signal in the putamen, pallidum, thalamus, midbrain, superior cerebellar gray, and white matter. [18F]-JNJ-067 significantly correlated (p < 0.05) with Mini-Mental State Exam in entorhinal cortex and temporal meta regions. There is clear binding of [18F]-JNJ-067 in AD participants. Lack of binding in HCs, MCIs and PSPs suggests [18F]-JNJ-067 may not bind to low levels of AD-related tau or 4 R tau.
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Affiliation(s)
- Suzanne L Baker
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Karine Provost
- Memory and Aging Center, Department of Neurology, University of California, Berkeley, CA, USA
| | - Wesley Thomas
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - A J Whitman
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mustafa Janabi
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mark E Schmidt
- Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Maarten Timmers
- Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | | | - Gil D Rabinovici
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Memory and Aging Center, Department of Neurology, University of California, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.,Department of Radiology and Biomedical Imaging, University of California, Berkeley, CA, USA
| | - William J Jagust
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
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39
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Barthélemy NR, Toth B, Manser PT, Sanabria-Bohórquez S, Teng E, Keeley M, Bateman RJ, Weimer RM, Wildsmith KR. Site-Specific Cerebrospinal Fluid Tau Hyperphosphorylation in Response to Alzheimer's Disease Brain Pathology: Not All Tau Phospho-Sites are Hyperphosphorylated. J Alzheimers Dis 2021; 85:415-429. [PMID: 34806603 PMCID: PMC8842784 DOI: 10.3233/jad-210677] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Understanding patterns of association between CSF phosphorylated tau (p-tau) species and clinical disease severity will aid Alzheimer's disease (AD) diagnosis and treatment. OBJECTIVE To evaluate changes in tau phosphorylation ratios to brain imaging (amyloid PET, [18F]GTP1 PET, and MRI) and cognition across clinical stages of AD in two different cohorts. METHODS A mass spectrometry (MS)-based method was used to evaluate the relationship between p-tau/tau phosphorylation ratios on 11 sites in CSF and AD pathology measured by tau PET ([18F]GTP1) and amyloid PET ([18F]florbetapir or [18F]florbetaben). Cohort A included cognitively normal-amyloid negative (n = 6) and positive (n = 5) individuals, and amyloid positive prodromal (n = 13), mild (n = 12), and moderate AD patients (n = 10); and Cohort B included amyloid positive prodromal (n = 24) and mild (n = 40) AD patients. RESULTS In this cross-sectional analysis, we identified clusters of phosphosites with different profiles of phosphorylation ratios across stages of disease. Eight of 11 investigated sites were hyperphosphorylated and associated with the SUVR measures from [18F]GTP1 and amyloid PET. Novel sites 111, 153, and 208 may be relevant biomarkers for AD diagnosis to complement tau hyperphosphorylation measures on previously established sites 181, 205, 217, and 231. Hypophosphorylation was detected on residues 175, 199, and 202, and was inversely associated with [18F]GTP1 and amyloid PET. CONCLUSION Hyperphosphorylated and hypophosphorylated forms of tau are associated with AD pathologies, and due to their different site-specific profiles, they may be used in combination to assist with staging of disease.
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Affiliation(s)
| | - Balazs Toth
- Clinical Biostatistics, Genentech, Inc., South San Francisco, CA, USA
| | - Paul T Manser
- Clinical Biostatistics, Genentech, Inc., South San Francisco, CA, USA
| | | | - Edmond Teng
- Early Clinical Development, Genentech, Inc., South San Francisco, CA, USA
| | - Michael Keeley
- Portfolio Management and Operations, Genentech, Inc., South San Francisco, CA, USA
| | - Randall J Bateman
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Robby M Weimer
- Department of Biomedical Imaging, Genentech, Inc., South San Francisco, CA, USA
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40
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Sexton C, Snyder H, Beher D, Boxer AL, Brannelly P, Brion JP, Buée L, Cacace AM, Chételat G, Citron M, DeVos SL, Diaz K, Feldman HH, Frost B, Goate AM, Gold M, Hyman B, Johnson K, Karch CM, Kerwin DR, Koroshetz WJ, Litvan I, Morris HR, Mummery CJ, Mutamba J, Patterson MC, Quiroz YT, Rabinovici GD, Rommel A, Shulman MB, Toledo-Sherman LM, Weninger S, Wildsmith KR, Worley SL, Carrillo MC. Current directions in tau research: Highlights from Tau 2020. Alzheimers Dement 2021; 18:988-1007. [PMID: 34581500 DOI: 10.1002/alz.12452] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 07/07/2021] [Accepted: 07/22/2021] [Indexed: 11/07/2022]
Abstract
Studies supporting a strong association between tau deposition and neuronal loss, neurodegeneration, and cognitive decline have heightened the allure of tau and tau-related mechanisms as therapeutic targets. In February 2020, leading tau experts from around the world convened for the first-ever Tau2020 Global Conference in Washington, DC, co-organized and cosponsored by the Rainwater Charitable Foundation, the Alzheimer's Association, and CurePSP. Representing academia, industry, government, and the philanthropic sector, presenters and attendees discussed recent advances and current directions in tau research. The meeting provided a unique opportunity to move tau research forward by fostering global partnerships among academia, industry, and other stakeholders and by providing support for new drug discovery programs, groundbreaking research, and emerging tau researchers. The meeting also provided an opportunity for experts to present critical research-advancing tools and insights that are now rapidly accelerating the pace of tau research.
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Affiliation(s)
| | | | | | - Adam L Boxer
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, California, USA
| | - Pat Brannelly
- Alzheimer's Disease Data Initiative, Kirkland, WI, USA
| | - Jean-Pierre Brion
- Laboratory of Histology, Neuroanatomy and Neuropathology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Luc Buée
- Univ Lille, Inserm, CHU-Lille, Lille Neuroscience and Cognition, Place de Verdun, Lille, France
| | | | - Gaël Chételat
- Normandie Univ, UNICAEN, INSERM, U1237, PhIND "Physiopathology and Imaging of Neurological Disorders", Institut Blood and Brain @ Caen-Normandie, Cyceron, Caen, France
| | - Martin Citron
- Neuroscience TA, Braine l'Alleud, UCB Biopharma, Brussels, Belgium
| | - Sarah L DeVos
- Translational Sciences, Denali Therapeutics, San Francisco, California, USA
| | | | - Howard H Feldman
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Bess Frost
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Disorders, Department of Cell Systems & Anatomy, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Alison M Goate
- Ronald M. Loeb Center for Alzheimer's Disease, Department of Neuroscience, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Michael Gold
- AbbVie, Neurosciences Development, North Chicago, Illinois, USA
| | - Bradley Hyman
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Keith Johnson
- Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Celeste M Karch
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Diana R Kerwin
- Kerwin Medical Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Walter J Koroshetz
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
| | - Irene Litvan
- Parkinson and Other Movement Disorders Center, Department of Neurosciences, University of California San Diego, San Diego, California, USA
| | - Huw R Morris
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Catherine J Mummery
- Dementia Research Centre, National Hospital for Neurology and Neurosurgery, University College London, London, UK
| | | | - Marc C Patterson
- Departments of Neurology, Pediatrics and Medical Genetics, Mayo Clinic, Rochester, Minnesota, USA
| | - Yakeel T Quiroz
- Departments of Neurology and Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Gil D Rabinovici
- Memory & Aging Center, Departments of Neurology, Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Amy Rommel
- Tau Consortium, Rainwater Charitable Foundation, Fort Worth, Texas, USA
| | - Melanie B Shulman
- Neurodegeneration Development Unit, Biogen, Boston, Massachusetts, USA
| | | | | | - Kristin R Wildsmith
- Department of Biomarker Development, Genentech, South San Francisco, California, USA
| | - Susan L Worley
- Independent science writer, Bryn Mawr, Pennsylvania, USA
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Moloney CM, Lowe VJ, Murray ME. Visualization of neurofibrillary tangle maturity in Alzheimer's disease: A clinicopathologic perspective for biomarker research. Alzheimers Dement 2021; 17:1554-1574. [PMID: 33797838 PMCID: PMC8478697 DOI: 10.1002/alz.12321] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 01/11/2021] [Accepted: 02/03/2021] [Indexed: 12/29/2022]
Abstract
Neurofibrillary tangles, one of the neuropathologic hallmarks of Alzheimer's disease, have a dynamic lifespan of maturity that associates with progressive neuronal dysfunction and cognitive deficits. As neurofibrillary tangles mature, the biology of the neuron undergoes extensive changes that may impact biomarker recognition and therapeutic targeting. Neurofibrillary tangle maturity encompasses three levels: pretangles, mature tangles, and ghost tangles. In this review, we detail distinct and overlapping characteristics observed in the human brain regarding morphologic changes the neuron undergoes, conversion from intracellular to extracellular space, tau immunostaining patterns, and tau isoform expression changes across the lifespan of the neurofibrillary tangle. Post-translational modifications of tau such as phosphorylation, ubiquitination, conformational events, and truncations are discussed to contextualize tau immunostaining patterns. We summarize accumulated and emerging knowledge of neurofibrillary tangle maturity, discuss the current tools used to interpret the dynamic nature in the postmortem brain, and consider implications for cognitive dysfunction and tau biomarkers.
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Affiliation(s)
| | - Val J. Lowe
- Department of RadiologyMayo ClinicRochesterMinnesotaUSA
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42
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Whittington A, Gunn RN. Tau IQ: A Canonical Image Based Algorithm to Quantify Tau PET Scans. J Nucl Med 2021; 62:1292-1300. [PMID: 33517326 PMCID: PMC8882899 DOI: 10.2967/jnumed.120.258962] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 01/13/2021] [Indexed: 12/20/2022] Open
Abstract
Recently, AmyloidIQ was introduced as a new canonical image-based algorithm to quantify amyloid PET scans and demonstrated increased power over traditional SUV ratio (SUVR) approaches when assessed in cross-sectional and longitudinal analyses. We build further on this mathematical framework to develop a TauIQ algorithm for the quantitative analysis of the more complex spatial distribution displayed by tau PET radiotracers. Methods: Cross-sectional (n = 615) and longitudinal (n = 149) 18F-flortaucipir data were obtained from the Alzheimer's Disease Neuroimaging Initiative along with necessary adjunct amyloid PET and T1-weighted structural MRI data. A subset of these data were used to derive a chronological tau dataset, using AmyloidIQ analysis of associated amyloid PET data to calculate the subject's temporal position in the canonical AD disease process, from which canonical images for the nonspecific and specific binding components of 18F-flortaucipir in AD were calculated. These 2 canonical images were incorporated into the TauIQ algorithm that enables the quantification of both global and local tau outcome measures using an image-based regression and statistical parametric analysis of the initial residual image. Performance of the TauIQ algorithm was compared with SUVR approaches for cross-sectional analyses, longitudinal analyses, and correlation with clinical measures (Alzheimer Disease Assessment Scale-Cognitive Subscale [ADAS-Cog], Clinical Dementia Rating scale-sum of boxes [CDR-SB], and Mini-Mental State Examination [MMSE]). Results: TauIQ successfully calculated global tau load (TauL) in all 791 scans analyzed (range, -3.5% to 185.2%; mean ± SD, 23% ± 20.5%) with a nonzero additional local tau component being required in 31% of all scans (cognitively normal [CN], 22%; mild cognitive impairment [MCI], 35%; dementia, 72%). TauIQ was compared with the best SUVR approach in the cross-sectional analysis (TauL increase in effect size: CN- vs. CN+, +45%; CN- vs. MCI+, -5.6%; CN- vs. dementia+, +2.3%) (+/- indicates amyloid-positive or -negative) and correlation with clinical scores (TauL increase in r2: CDR-SB+, 7%; MMSE+, 38%; ADAS-Cog+, 0%). TauIQ substantially outperformed SUVR approaches in the longitudinal analysis (TauIQ increase in power: CN+, >3.2-fold; MCI+, >2.2-fold; dementia+, >2.9-fold). Conclusion: TauL as calculated by TauIQ provides a superior approach for the quantification of tau PET data. In particular, it provides a substantial improvement in power for longitudinal analyses and the early detection of tau deposition and thus should have significant value for clinical imaging trials in AD that are investigating the attenuation of tau deposition with novel therapies.
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Affiliation(s)
| | - Roger N Gunn
- Invicro LLC, London, United Kingdom; and
- Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, United Kingdom
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Bischof GN, Dodich A, Boccardi M, van Eimeren T, Festari C, Barthel H, Hansson O, Nordberg A, Ossenkoppele R, Sabri O, Giovanni BFG, Garibotto V, Drzezga A. Clinical validity of second-generation tau PET tracers as biomarkers for Alzheimer's disease in the context of a structured 5-phase development framework. Eur J Nucl Med Mol Imaging 2021; 48:2110-2120. [PMID: 33590274 PMCID: PMC8175320 DOI: 10.1007/s00259-020-05156-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE In 2017, the Geneva Alzheimer's disease (AD) strategic biomarker roadmap initiative proposed a framework of the systematic validation AD biomarkers to harmonize and accelerate their development and implementation in clinical practice. Here, we use this framework to examine the translatability of the second-generation tau PET tracers into the clinical context. METHODS All available literature was systematically searched based on a set of search terms that related independently to analytic validity (phases 1-2), clinical validity (phase 3-4), and clinical utility (phase 5). The progress on each of the phases was determined based on scientific criteria applied for each phase and coded as fully, partially, preliminary achieved or not achieved at all. RESULTS The validation of the second-generation tau PET tracers has successfully passed the analytical phase 1 of the strategic biomarker roadmap. Assay definition studies showed evidence on the superiority over first-generation tau PET tracers in terms of off-target binding. Studies have partially achieved the primary aim of the analytical validity stage (phase 2), and preliminary evidence has been provided for the assessment of covariates on PET signal retention. Studies investigating of the clinical validity in phases 3, 4, and 5 are still underway. CONCLUSION The current literature provides overall preliminary evidence on the establishment of the second-generation tau PET tracers into the clinical context, thereby successfully addressing some methodological issues from the tau PET tracer of the first generation. Nevertheless, bigger cohort studies, longitudinal follow-up, and examination of diverse disease population are still needed to gauge their clinical validity.
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Affiliation(s)
- Gérard N Bischof
- Department of Nuclear Medicine, University Hospital Cologne, Cologne, Germany.
| | - Alessandra Dodich
- NIMTlab, Neuroimaging and Innovative Molecular Tracers Laboratory, University of Geneva, Geneva, Switzerland
- Center for Neurocognitive Rehabilitation (CeRiN), CIMeC, University of Trento, Trento, Italy
| | - Marina Boccardi
- German Center for Neurodegenerative Disorders (DZNE), Rostock/Greifswald, Rostock, Germany
- German Center for Neurodegenerative Disorders (DZNE), Bonn/Cologne, Germany
| | - Thilo van Eimeren
- Department of Nuclear Medicine, University Hospital Cologne, Cologne, Germany
- German Center for Neurodegenerative Disorders (DZNE), Rostock/Greifswald, Rostock, Germany
- German Center for Neurodegenerative Disorders (DZNE), Bonn/Cologne, Germany
| | - Cristina Festari
- LANE - Laboratory of Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Henryk Barthel
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - Oskar Hansson
- Memory Clinic, Skåne University Hopsital, Malmö, Sweden
- Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Rik Ossenkoppele
- Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, Netherlands
| | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - B Frisoni G Giovanni
- NIMTlab, Neuroimaging and Innovative Molecular Tracers Laboratory, University of Geneva, Geneva, Switzerland
- Memory Center - Department of Rehabilitation and Geriatrics, Geneva University Hospitals, Geneva, Switzerland
| | - Valentina Garibotto
- NIMTlab, Neuroimaging and Innovative Molecular Tracers Laboratory, University of Geneva, Geneva, Switzerland
- Nuclear Medicine and Molecular Imaging Division, Diagnostic Department, Geneva University Hospitals, Genève, Switzerland
| | - Alexander Drzezga
- Department of Nuclear Medicine, University Hospital Cologne, Cologne, Germany
- German Center for Neurodegenerative Disorders (DZNE), Rostock/Greifswald, Rostock, Germany
- German Center for Neurodegenerative Disorders (DZNE), Bonn/Cologne, Germany
- Molecular Organization of the Brain, Institute for Neuroscience and Medicine (INM-2), Jülich, Germany
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(S)-[ 18F]THK5117 brain uptake is associated with Aβ plaques and MAO-B enzyme in a mouse model of Alzheimer's disease. Neuropharmacology 2021; 196:108676. [PMID: 34216585 DOI: 10.1016/j.neuropharm.2021.108676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 12/12/2022]
Abstract
The mouse model of beta-amyloid (Aβ) deposition, APP/PS1-21, exhibits high brain uptake of the tau-tracer (S)-[18F]THK5117, although no neurofibrillary tangles are present in this mouse model. For this reason we investigated (S)-[18F]THK5117 off-target binding to Aβ plaques and MAO-B enzyme in APP/PS1-21 transgenic (TG) mouse model of Aβ deposition. APP/PS1-21 TG and wild-type (WT) control mice in four different age groups (2-26 months) were imaged antemortem by positron emission tomography with (S)-[18F]THK5117, and then brain autoradiography. Additional animals were used for immunohistochemical staining and MAO-B enzyme blocking study with deprenyl pre-treatment. Regional standardized uptake value ratios for the cerebellum revealed a significant temporal increase in (S)-[18F]THK5117 uptake in aged TG, but not WT, brain. Immunohistochemical staining revealed a similar increase in Aβ plaques but not endogenous hyper-phosphorylated tau or MAO-B enzyme, and ex vivo autography showed that uptake of (S)-[18F]THK5117 co-localized with the amyloid pathology. Deprenyl hydrochloride pre-treatment reduced the binding of (S)-[18F]THK5117 in the neocortex, hippocampus, and thalamus. This study's findings suggest that increased (S)-[18F]THK5117 binding in aging APP/PS1-21 TG mice is mainly due to increasing Aβ deposition, and to a lesser extent binding to MAO-B enzyme, but not hyper-phosphorylated tau.
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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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An Update on the State of Tau Radiotracer Development: a Brief Review. Mol Imaging Biol 2021; 23:797-808. [PMID: 33987775 DOI: 10.1007/s11307-021-01612-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
Evolving scientific evidence has begun to point towards hyperphosphorylated tau as a major neurotoxic component in the pathophysiological development of many major neurodegenerative conditions. In response to a need for accurate and reliable diagnosis and disease monitoring in clinical and trial settings, there has been great effort put into the development of tau radiotracers. While first-generation and second-generation radiotracers have provided a basis for assessing tau, concerns of inadequate specificity and selectivity have continued to motivate further study of these radiotracers and the development of novel radiopharmaceuticals. Given the prospective scientific and clinical value of a valid tau radiotracer, the molecular neuroimaging community must be aware of the most recent developments in the realm of tau radiotracer development. This brief review article will critically overview the most established tau radiotracers and, most importantly, concentrate on the progress of more recently developed tau radiotracers.
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Ossenkoppele R, Hansson O. Towards clinical application of tau PET tracers for diagnosing dementia due to Alzheimer's disease. Alzheimers Dement 2021; 17:1998-2008. [PMID: 33984177 DOI: 10.1002/alz.12356] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/22/2021] [Accepted: 03/28/2021] [Indexed: 11/07/2022]
Abstract
The recent development of several tau positron emission tomography (PET) tracers represents a major milestone for the Alzheimer's disease (AD) field. These tau PET tracers bind tau neurofibrillary tangles, a key neuropathological characteristic of AD that is tightly linked to synaptic loss, brain atrophy, and cognitive decline. It is notable that these tau PET tracers show low uptake in most non-AD tauopathies and other neurodegenerative disorders, resulting in a diagnostic specificity that is superior to that of amyloid beta (Aβ) PET and biofluid markers, especially at an older age when incidental Aβ pathology is common. Furthermore, tau PET tracers diagnostically outperform widely used MRI markers. Given its excellent diagnostic performance due to the combination of high sensitivity and specificity for detecting tau pathology in AD dementia, we hypothesize that tau PET can become an important diagnostic tool in specialized clinics for the differential diagnosis of dementia syndromes where AD is among the major possible underlying diseases.
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Affiliation(s)
- Rik Ossenkoppele
- Lund University, Clinical Memory Research Unit, Lund, Sweden.,Department of Neurology, Amsterdam Neuroscience, Alzheimer Center Amsterdam, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - Oskar Hansson
- Lund University, Clinical Memory Research Unit, Lund, Sweden.,Memory Clinic, Skåne University Hospital, Malmö, Sweden
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Klenner MA, Pascali G, Fraser BH, Darwish TA. Kinetic isotope effects and synthetic strategies for deuterated carbon-11 and fluorine-18 labelled PET radiopharmaceuticals. Nucl Med Biol 2021; 96-97:112-147. [PMID: 33892374 DOI: 10.1016/j.nucmedbio.2021.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 11/22/2022]
Abstract
The deuterium labelling of pharmaceuticals is a useful strategy for altering pharmacokinetic properties, particularly for improving metabolic resistance. The pharmacological effects of such metabolites are often assumed to be negligible during standard drug discovery and are factored in later at the clinical phases of development, where the risks and benefits of the treatment and side-effects can be wholly assessed. This paradigm does not translate to the discovery of radiopharmaceuticals, however, as the confounding effects of radiometabolites can inevitably show in preliminary positron emission tomography (PET) scans and thus complicate interpretation. Consequently, the formation of radiometabolites is crucial to take into consideration, compared to non-radioactive metabolites, and the application of deuterium labelling is a particularly attractive approach to minimise radiometabolite formation. Herein, we provide a comprehensive overview of the deuterated carbon-11 and fluorine-18 radiopharmaceuticals employed in PET imaging experiments. Specifically, we explore six categories of deuterated radiopharmaceuticals used to investigate the activities of monoamine oxygenase (MAO), choline, translocator protein (TSPO), vesicular monoamine transporter 2 (VMAT2), neurotransmission and the diagnosis of Alzheimer's disease; from which we derive four prominent deuteration strategies giving rise to a kinetic isotope effect (KIE) for reducing the rate of metabolism. Synthetic approaches for over thirty of these deuterated radiopharmaceuticals are discussed from the perspective of deuterium and radioisotope incorporation, alongside an evaluation of the deuterium labelling and radiolabelling efficacies across these independent studies. Clinical and manufacturing implications are also discussed to provide a more comprehensive overview of how deuterated radiopharmaceuticals may be introduced to routine practice.
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Affiliation(s)
- Mitchell A Klenner
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia; Department of Nuclear Medicine and PET, Liverpool Hospital, Liverpool, NSW 2170, Australia.
| | - Giancarlo Pascali
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia; Department of Nuclear Medicine and PET, Prince of Wales Hospital, Randwick, NSW 2031, Australia; School of Chemistry, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Benjamin H Fraser
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Tamim A Darwish
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
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Leuzy A, Smith R, Ossenkoppele R, Santillo A, Borroni E, Klein G, Ohlsson T, Jögi J, Palmqvist S, Mattsson-Carlgren N, Strandberg O, Stomrud E, Hansson O. Diagnostic Performance of RO948 F 18 Tau Positron Emission Tomography in the Differentiation of Alzheimer Disease From Other Neurodegenerative Disorders. JAMA Neurol 2021; 77:955-965. [PMID: 32391858 PMCID: PMC7215644 DOI: 10.1001/jamaneurol.2020.0989] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Question How does RO948 F 18 positron emission tomographic scanning discriminate between Alzheimer disease and other neurodegenerative disorders in comparison with magnetic resonance imaging and cerebrospinal fluid measures? Findings In this diagnostic study including 613 patients from the Swedish BioFINDER-2 clinical trial, standard uptake value ratios of RO948 F 18 were higher in patients with Alzheimer disease dementia compared with cognitively unimpaired controls and patients with other neurodegenerative disorders; furthermore, RO948 F 18 outperformed magnetic resonance imaging and cerebrospinal fluid measures. Generally, tau positron emission tomographic positivity was confined to amyloid β–positive cases or MAPT R406W mutation carriers in this cohort; in patients with semantic variant primary progressive aphasia, RO948 F 18 retention was lower than that for flortaucipir F 18. Meaning These findings suggest that RO948 F 18 has a high specificity for Alzheimer disease–type tau and highlight its potential as a diagnostic marker in the workup of patients treated in memory clinics. Importance The diagnostic performance of second-generation tau positron emission tomographic (PET) tracers is not yet known. Objective To examine the novel tau PET tracer RO948 F 18 ([18F]RO948) performance in discriminating Alzheimer disease (AD) from non-AD neurodegenerative disorders. Design, Setting, and Participants In this diagnostic study, 613 participants in the Swedish BioFINDER-2 study were consecutively enrolled in a prospective cross-sectional study from September 4, 2017, to August 28, 2019. Participants included 257 cognitively unimpaired controls, 154 patients with mild cognitive impairment, 100 patients with AD dementia, and 102 with non-AD neurodegenerative disorders. Evaluation included a comparison of tau PET tracer [18F]RO948 with magnetic resonance imaging (MRI) and cerebrospinal fluid and a head-to-head comparison between [18F]RO948 and flortaucipir F 18 ([18F]flortaucipir) in patients with semantic variant primary progressive aphasia (svPPA). Exposures [18F]RO948 (all patients) and [18F]flortaucipir (3 patients with svPPA) tau PET; MRI (hippocampal volume, composite temporal lobe cortical thickness, whole-brain cortical thickness) and cerebrospinal fluid measures (p-tau181 and amyloid Aβ42 and Aβ40 ratio[Aβ42/Aβ40], and Aβ42/p-tau181 ratio). Main Outcomes and Measures Standard uptake value ratios (SUVRs) in 4 predefined regions of interest (ROIs) reflecting Braak staging scheme for tau pathology and encompass I-II (entorhinal cortex), III-IV (inferior/middle temporal, fusiform gyrus, parahippocampal cortex, and amygdala), I-IV, and V-VI (widespread neocortical areas), area under the receiver operating characteristic curve (AUC) values, and subtraction images between [18F]RO948 and [18F]flortaucipir. Results Diagnostic groups among the 613 participants included cognitively unimpaired (mean [SD] age, 65.8 [12.1] years; 117 men [46%]), mild cognitive impairment (age, 70.8 [8.3] years; 82 men [53%]), AD dementia (age, 73.5 [6.7] years; 57 men [57%]), and non-AD disorders (age, 70.5 [8.6] years; 41 men [40%]). Retention of [18F]RO948 was higher in AD dementia compared with all other diagnostic groups. [18F]RO948 could distinguish patients with AD dementia from individuals without cognitive impairment and those with non-AD disorders, and the highest AUC was obtained using the I-IV ROI (AUC = 0.98; 95% CI, 0.96-0.99 for AD vs no cognitive impairment and AUC = 0.97; 95% CI, 0.95-0.99 for AD vs non-AD disorders), which outperformed MRI (highest AUC = 0.91 for AD vs no cognitive impairment using whole-brain thickness, and AUC = 0.80 for AD vs non-AD disorders using temporal lobe thickness) and cerebrospinal fluid measures (highest AUC = 0.94 for AD vs no cognitive impairment using Aβ42/p-tau181, and AUC = 0.93 for AD vs non-AD disorders using Aβ42/Aβ40). Generally, tau PET positivity using [18F]RO948 was observed only in Aβ-positive cases or in MAPT R406W mutation carriers. Retention of [18F]RO948 was not pronounced in patients with svPPA, and head-to-head comparison revealed lower temporal lobe uptake than with [18F]flortaucipir. Conclusions and Relevance In this study, elevated [18F]RO948 SUVRs were most often seen among Aβ-positive cases, which suggests that [18F]RO948 has high specificity for AD-type tau and highlights its potential as a diagnostic marker in the differential diagnosis of AD.
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Affiliation(s)
- Antoine Leuzy
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Ruben Smith
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.,Department of Neurology, Skåne University Hospital, Lund, Sweden
| | - Rik Ossenkoppele
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.,Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | | | | | | | - Tomas Ohlsson
- Department of Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Jonas Jögi
- Skåne University Hospital, Department of Clinical Physiology and Nuclear Medicine, Lund, Sweden
| | - Sebastian Palmqvist
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.,Department of Neurology, Skåne University Hospital, Lund, Sweden
| | - Niklas Mattsson-Carlgren
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.,Department of Neurology, Skåne University Hospital, Lund, Sweden.,Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Olof Strandberg
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Erik Stomrud
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.,Memory Clinic, Skåne University Hospital, Malmö, Sweden
| | - Oskar Hansson
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.,Memory Clinic, Skåne University Hospital, Malmö, Sweden
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Comprehensive review on design perspective of PET ligands based on β-amyloids, tau and neuroinflammation for diagnostic intervention of Alzheimer’s disease. Clin Transl Imaging 2021. [DOI: 10.1007/s40336-021-00410-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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