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Vogler L, Ballweg A, Bohr B, Briel N, Wind K, Antons M, Kunze LH, Gnörich J, Lindner S, Gildehaus FJ, Baumann K, Bartenstein P, Boening G, Ziegler SI, Levin J, Zwergal A, Höglinger GU, Herms J, Brendel M. Assessment of synaptic loss in mouse models of β-amyloid and tau pathology using [ 18F]UCB-H PET imaging. Neuroimage Clin 2023; 39:103484. [PMID: 37541098 PMCID: PMC10407951 DOI: 10.1016/j.nicl.2023.103484] [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: 01/09/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/06/2023]
Abstract
OBJECTIVE In preclinical research, the use of [18F]Fluorodesoxyglucose (FDG) as a biomarker for neurodegeneration may induce bias due to enhanced glucose uptake by immune cells. In this study, we sought to investigate synaptic vesicle glycoprotein 2A (SV2A) PET with [18F]UCB-H as an alternative preclinical biomarker for neurodegenerative processes in two mouse models representing the pathological hallmarks of Alzheimer's disease (AD). METHODS A total of 29 PS2APP, 20 P301S and 12 wild-type mice aged 4.4 to 19.8 months received a dynamic [18F]UCB-H SV2A-PET scan (14.7 ± 1.5 MBq) 0-60 min post injection. Quantification of tracer uptake in cortical, cerebellar and brainstem target regions was implemented by calculating relative volumes of distribution (VT) from an image-derived-input-function (IDIF). [18F]UCB-H binding was compared across all target regions between transgenic and wild-type mice. Additional static scans were performed in a subset of mice to compare [18F]FDG and [18F]GE180 (18 kDa translocator protein tracer as a surrogate for microglial activation) standardized uptake values (SUV) with [18F]UCB-H binding at different ages. Following the final scan, a subset of mouse brains was immunohistochemically stained with synaptic markers for gold standard validation of the PET results. RESULTS [18F]UCB-H binding in all target regions was significantly reduced in 8-months old P301S transgenic mice when compared to wild-type controls (temporal lobe: p = 0.014; cerebellum: p = 0.0018; brainstem: p = 0.0014). Significantly lower SV2A tracer uptake was also observed in 13-months (temporal lobe: p = 0.0080; cerebellum: p = 0.006) and 19-months old (temporal lobe: p = 0.0042; cerebellum: p = 0.011) PS2APP transgenic versus wild-type mice, whereas the brainstem revealed no significantly altered [18F]UCB-H binding. Immunohistochemical analyses of post-mortem mouse brain tissue confirmed the SV2A PET findings. Correlational analyses of [18F]UCB-H and [18F]FDG using Pearson's correlation coefficient revealed a significant negative association in the PS2APP mouse model (R = -0.26, p = 0.018). Exploratory analyses further stressed microglial activation as a potential reason for this inverse relationship, since [18F]FDG and [18F]GE180 quantification were positively correlated in this cohort (R = 0.36, p = 0.0076). CONCLUSION [18F]UCB-H reliably depicts progressive synaptic loss in PS2APP and P301S transgenic mice, potentially qualifying as a more reliable alternative to [18F]FDG as a biomarker for assessment of neurodegeneration in preclinical research.
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Affiliation(s)
- Letizia Vogler
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Anna Ballweg
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Bernd Bohr
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Nils Briel
- Center for Neuropathology, LMU Munich, Munich, Germany
| | - Karin Wind
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Melissa Antons
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Lea H Kunze
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Johannes Gnörich
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Franz-Josef Gildehaus
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Karlheinz Baumann
- Roche Pharma Research and Early Development, Neuroscience Discovery, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Guido Boening
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Sibylle I Ziegler
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | - Johannes Levin
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Department of Neurology, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Andreas Zwergal
- Department of Neurology, University Hospital of Munich, LMU Munich, Munich, Germany; German Center for Vertigo and Balance Disorders (DSGZ), University Hospital of Munich, LMU Munich, Munich, Germany
| | - Günter U Höglinger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Department of Neurology, University Hospital of Munich, LMU Munich, Munich, Germany
| | - Jochen Herms
- Center for Neuropathology, LMU Munich, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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Zheng C, Toyonaga T, Chen B, Nicholson L, Mennie W, Liu M, Spurrier J, Deluca K, Strittmatter SM, Carson RE, Huang Y, Cai Z. Decreased synaptic vesicle glycoprotein 2A binding in a rodent model of familial Alzheimer's disease detected by [ 18F]SDM-16. Front Neurol 2023; 14:1045644. [PMID: 36846134 PMCID: PMC9945093 DOI: 10.3389/fneur.2023.1045644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 01/17/2023] [Indexed: 02/11/2023] Open
Abstract
Introduction Synapse loss is one of the hallmarks of Alzheimer's disease (AD) and is associated with cognitive decline. In this study, we tested [18F]SDM-16, a novel metabolically stable SV2A PET imaging probe, in the transgenic APPswe/PS1dE9 (APP/PS1) mouse model of AD and age-matched wild-type (WT) mice at 12 months of age. Methods Based on previous preclinical PET imaging studies using [11C]UCB-J and [18F]SynVesT-1 in the same strain animals, we used the simplified reference tissue model (SRTM), with brain stem as the pseudo reference region to calculate distribution volume ratios (DVRs). Results To simplify and streamline the quantitative analysis, we compared the standardized uptake value ratios (SUVRs) from different imaging windows to DVRs and found that the averaged SUVRs from 60-90 min post-injection (p.i.) are most consistent with the DVRs. Thus, we used averaged SUVRs from 60-90 min for group comparisons and found statistically significant differences in the tracer uptake in different brain regions, e.g., hippocampus (p = 0.001), striatum (p = 0.002), thalamus (p = 0.003), and cingulate cortex (p = 0.0003). Conclusions In conclusion, [18F]SDM-16 was used to detect decreased SV2A levels in the brain of APP/PS1 AD mouse model at one year old. Our data suggest that [18F]SDM-16 has similar statistical power in detecting the synapse loss in APP/PS1 mice as [11C]UCB-J and [18F]SynVesT-1, albeit later imaging window (60-90 min p.i.) is needed when SUVR is used as a surrogate for DVR for [18F]SDM-16 due to its slower brain kinetics.
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Affiliation(s)
- Chao Zheng
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - Takuya Toyonaga
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - Baosheng Chen
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - LaShae Nicholson
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Departments of Neuroscience and Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - William Mennie
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - Michael Liu
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - Joshua Spurrier
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Departments of Neuroscience and Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - Kristin Deluca
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Departments of Neuroscience and Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - Stephen M. Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Departments of Neuroscience and Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - Richard E. Carson
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
| | - Zhengxin Cai
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, United States
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Ribarič S. Detecting Early Cognitive Decline in Alzheimer's Disease with Brain Synaptic Structural and Functional Evaluation. Biomedicines 2023; 11:biomedicines11020355. [PMID: 36830892 PMCID: PMC9952956 DOI: 10.3390/biomedicines11020355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
Early cognitive decline in patients with Alzheimer's (AD) is associated with quantifiable structural and functional connectivity changes in the brain. AD dysregulation of Aβ and tau metabolism progressively disrupt normal synaptic function, leading to loss of synapses, decreased hippocampal synaptic density and early hippocampal atrophy. Advances in brain imaging techniques in living patients have enabled the transition from clinical signs and symptoms-based AD diagnosis to biomarkers-based diagnosis, with functional brain imaging techniques, quantitative EEG, and body fluids sampling. The hippocampus has a central role in semantic and episodic memory processing. This cognitive function is critically dependent on normal intrahippocampal connections and normal hippocampal functional connectivity with many cortical regions, including the perirhinal and the entorhinal cortex, parahippocampal cortex, association regions in the temporal and parietal lobes, and prefrontal cortex. Therefore, decreased hippocampal synaptic density is reflected in the altered functional connectivity of intrinsic brain networks (aka large-scale networks), including the parietal memory, default mode, and salience networks. This narrative review discusses recent critical issues related to detecting AD-associated early cognitive decline with brain synaptic structural and functional markers in high-risk or neuropsychologically diagnosed patients with subjective cognitive impairment or mild cognitive impairment.
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Affiliation(s)
- Samo Ribarič
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia
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Rossi R, Arjmand S, Bærentzen SL, Gjedde A, Landau AM. Synaptic Vesicle Glycoprotein 2A: Features and Functions. Front Neurosci 2022; 16:864514. [PMID: 35573314 PMCID: PMC9096842 DOI: 10.3389/fnins.2022.864514] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/05/2022] [Indexed: 01/05/2023] Open
Abstract
In recent years, the field of neuroimaging dramatically moved forward by means of the expeditious development of specific radioligands of novel targets. Among these targets, the synaptic vesicle glycoprotein 2A (SV2A) is a transmembrane protein of synaptic vesicles, present in all synaptic terminals, irrespective of neurotransmitter content. It is involved in key functions of neurons, focused on the regulation of neurotransmitter release. The ubiquitous expression in gray matter regions of the brain is the basis of its candidacy as a marker of synaptic density. Following the development of molecules derived from the structure of the anti-epileptic drug levetiracetam, which selectively binds to SV2A, several radiolabeled markers have been synthetized to allow the study of SV2A distribution with positron emission tomography (PET). These radioligands permit the evaluation of in vivo changes of SV2A distribution held to be a potential measure of synaptic density in physiological and pathological conditions. The use of SV2A as a biomarker of synaptic density raises important questions. Despite numerous studies over the last decades, the biological function and the expressional properties of SV2A remain poorly understood. Some functions of SV2A were claimed, but have not been fully elucidated. While the expression of SV2A is ubiquitous, stronger associations between SV2A and Υ amino butyric acid (GABA)-ergic rather than glutamatergic synapses were observed in some brain structures. A further issue is the unclear interaction between SV2A and its tracers, which reflects a need to clarify what really is detected with neuroimaging tools. Here, we summarize the current knowledge of the SV2A protein and we discuss uncertain aspects of SV2A biology and physiology. As SV2A expression is ubiquitous, but likely more strongly related to a certain type of neurotransmission in particular circumstances, a more extensive knowledge of the protein would greatly facilitate the analysis and interpretation of neuroimaging results by allowing the evaluation not only of an increase or decrease of the protein level, but also of the type of neurotransmission involved.
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Affiliation(s)
- Rachele Rossi
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Shokouh Arjmand
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Simone Larsen Bærentzen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Albert Gjedde
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Anne M Landau
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
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Serrano ME, Kim E, Petrinovic MM, Turkheimer F, Cash D. Imaging Synaptic Density: The Next Holy Grail of Neuroscience? Front Neurosci 2022; 16:796129. [PMID: 35401097 PMCID: PMC8990757 DOI: 10.3389/fnins.2022.796129] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/15/2022] [Indexed: 12/19/2022] Open
Abstract
The brain is the central and most complex organ in the nervous system, comprising billions of neurons that constantly communicate through trillions of connections called synapses. Despite being formed mainly during prenatal and early postnatal development, synapses are continually refined and eliminated throughout life via complicated and hitherto incompletely understood mechanisms. Failure to correctly regulate the numbers and distribution of synapses has been associated with many neurological and psychiatric disorders, including autism, epilepsy, Alzheimer’s disease, and schizophrenia. Therefore, measurements of brain synaptic density, as well as early detection of synaptic dysfunction, are essential for understanding normal and abnormal brain development. To date, multiple synaptic density markers have been proposed and investigated in experimental models of brain disorders. The majority of the gold standard methodologies (e.g., electron microscopy or immunohistochemistry) visualize synapses or measure changes in pre- and postsynaptic proteins ex vivo. However, the invasive nature of these classic methodologies precludes their use in living organisms. The recent development of positron emission tomography (PET) tracers [such as (18F)UCB-H or (11C)UCB-J] that bind to a putative synaptic density marker, the synaptic vesicle 2A (SV2A) protein, is heralding a likely paradigm shift in detecting synaptic alterations in patients. Despite their limited specificity, novel, non-invasive magnetic resonance (MR)-based methods also show promise in inferring synaptic information by linking to glutamate neurotransmission. Although promising, all these methods entail various advantages and limitations that must be addressed before becoming part of routine clinical practice. In this review, we summarize and discuss current ex vivo and in vivo methods of quantifying synaptic density, including an evaluation of their reliability and experimental utility. We conclude with a critical assessment of challenges that need to be overcome before successfully employing synaptic density biomarkers as diagnostic and/or prognostic tools in the study of neurological and neuropsychiatric disorders.
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Affiliation(s)
- Maria Elisa Serrano
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Eugene Kim
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Marija M Petrinovic
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Diana Cash
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
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Longitudinal [18]UCB-H/[18F]FDG imaging depicts complex patterns of structural and functional neuroplasticity following bilateral vestibular loss in the rat. Sci Rep 2022; 12:6049. [PMID: 35411002 PMCID: PMC9001652 DOI: 10.1038/s41598-022-09936-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/23/2022] [Indexed: 11/10/2022] Open
Abstract
Neuronal lesions trigger mechanisms of structural and functional neuroplasticity, which can support recovery. However, the temporal and spatial appearance of structure–function changes and their interrelation remain unclear. The current study aimed to directly compare serial whole-brain in vivo measurements of functional plasticity (by [18F]FDG-PET) and structural synaptic plasticity (by [18F]UCB-H-PET) before and after bilateral labyrinthectomy in rats and investigate the effect of locomotor training. Complex structure–function changes were found after bilateral labyrinthectomy: in brainstem-cerebellar circuits, regional cerebral glucose metabolism (rCGM) decreased early, followed by reduced synaptic density. In the thalamus, increased [18F]UCB-H binding preceded a higher rCGM uptake. In frontal-basal ganglia loops, an increase in synaptic density was paralleled by a decrease in rCGM. In the group with locomotor training, thalamic rCGM and [18F]UCB-H binding increased following bilateral labyrinthectomy compared to the no training group. Rats with training had considerably fewer body rotations. In conclusion, combined [18F]FDG/[18F]UCB-H dual tracer imaging reveals that adaptive neuroplasticity after bilateral vestibular loss is not a uniform process but is composed of complex spatial and temporal patterns of structure–function coupling in networks for vestibular, multisensory, and motor control, which can be modulated by early physical training.
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Goutal S, Guillermier M, Becker G, Gaudin M, Bramoullé Y, Luxen A, Lemaire C, Plenevaux A, Salmon E, Hantraye P, Barret O, Van Camp N. The pharmacokinetics of [ 18F]UCB-H revisited in the healthy non-human primate brain. EJNMMI Res 2021; 11:36. [PMID: 33826008 PMCID: PMC8026785 DOI: 10.1186/s13550-021-00777-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/22/2021] [Indexed: 12/29/2022] Open
Abstract
Background Positron Emission Tomography (PET) imaging of the Synaptic Vesicle glycoprotein (SV) 2A is a new tool to quantify synaptic density. [18F]UCB-H was one of the first promising SV2A-ligands to be labelled and used in vivo in rodent and human, while limited information on its pharmacokinetic properties is available in the non-human primate. Here, we evaluate the reliability of the three most commonly used modelling approaches for [18F]UCB-H in the non-human cynomolgus primate, adding the coupled fit of the non-displaceable distribution volume (VND) as an alternative approach to improve unstable fit. The results are discussed in the light of the current state of SV2A PET ligands. Results [18F]UCB-H pharmacokinetic data was optimally fitted with a two-compartment model (2TCM), although the model did not always converge (large total volume of distribution (VT) or large uncertainty of the estimate). 2TCM with coupled fit K1/k2 across brain regions stabilized the quantification, and confirmed a lower specific signal of [18F]UCB-H compared to the newest SV2A-ligands. However, the measures of VND and the influx parameter (K1) are similar to what has been reported for other SV2A ligands. These data were reinforced by displacement studies using [19F]UCB-H, demonstrating only 50% displacement of the total [18F]UCB-H signal at maximal occupancy of SV2A. As previously demonstrated in clinical studies, the graphical method of Logan provided a more robust estimate of VT with only a small bias compared to 2TCM. Conclusions Modeling issues with a 2TCM due to a slow component have previously been reported for other SV2A ligands with low specific binding, or after blocking of specific binding. As all SV2A ligands share chemical structural similarities, we hypothesize that this slow binding component is common for all SV2A ligands, but only hampers quantification when specific binding is low. Supplementary Information The online version contains supplementary material available at 10.1186/s13550-021-00777-8.
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Affiliation(s)
- Sébastien Goutal
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
| | - Martine Guillermier
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
| | - Guillaume Becker
- GIGA Cyclotron Research Centre In Vivo Imaging, University of Liege, Allee du 6 Aout, 8, Sart Tilman B30, 4000, Liege, Belgium
| | - Mylène Gaudin
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
| | - Yann Bramoullé
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
| | - André Luxen
- GIGA Cyclotron Research Centre In Vivo Imaging, University of Liege, Allee du 6 Aout, 8, Sart Tilman B30, 4000, Liege, Belgium
| | - Christian Lemaire
- GIGA Cyclotron Research Centre In Vivo Imaging, University of Liege, Allee du 6 Aout, 8, Sart Tilman B30, 4000, Liege, Belgium
| | - Alain Plenevaux
- GIGA Cyclotron Research Centre In Vivo Imaging, University of Liege, Allee du 6 Aout, 8, Sart Tilman B30, 4000, Liege, Belgium
| | - Eric Salmon
- GIGA Cyclotron Research Centre In Vivo Imaging, University of Liege, Allee du 6 Aout, 8, Sart Tilman B30, 4000, Liege, Belgium
| | - Philippe Hantraye
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
| | - Olivier Barret
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
| | - Nadja Van Camp
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire Des Maladies Neurodégénératives, 18 Route du Panorama, 92265, Fontenay-aux-Roses, France.
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Serrano ME, Bahri MA, Becker G, Seret A, Germonpré C, Lemaire C, Giacomelli F, Mievis F, Luxen A, Salmon E, Rogister B, Raedt R, Plenevaux A. Exploring with [ 18F]UCB-H the in vivo Variations in SV2A Expression through the Kainic Acid Rat Model of Temporal Lobe Epilepsy. Mol Imaging Biol 2020; 22:1197-1207. [PMID: 32206990 PMCID: PMC7497718 DOI: 10.1007/s11307-020-01488-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE The main purpose of this study was to understand how the positron emission tomography (PET) measure of the synaptic vesicle 2A (SV2A) protein varies in vivo during the development of temporal lobe epilepsy (TLE) in the kainic acid rat model. PROCEDURES Twenty Sprague Dawley male rats were administered with multiple systemic doses of saline (control group, n = 5) or kainic acid (5 mg/kg/injection, epileptic group, n = 15). Both groups were scanned at the four phases of TLE (early, latent, transition, and chronic phase) with the [18F]UCB-H PET radiotracer and T2-structural magnetic resonance imaging. At the end of the scans (3 months post-status epilepticus), rats were monitored for 7 days with electroencephalography for the detection of spontaneous electrographic seizures. Finally, the immunofluorescence staining for SV2A expression was performed. RESULTS Control rats presented a significant increase in [18F]UCB-H binding at the last two scans, compared with the first ones (p < 0.001). This increase existed but was lower in epileptic animals, producing significant group differences in all the phases of the disease (p < 0.028). Furthermore, the quantification of the SV2A expression in vivo with the [18F]UCB-H radiotracer or ex vivo with immunofluorescence led to equivalent results, with a positive correlation between both. CONCLUSIONS Even if further studies in humans are required, the ability to detect a progressive decrease in SV2A expression during the development of temporal lobe epilepsy supports the use of [18F]UCB-H as a useful tool to differentiate, in vivo, between healthy and epileptic animals along with the development of the epileptic disease.
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Affiliation(s)
- Maria Elisa Serrano
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium.
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 9NU, UK.
| | - Mohamed Ali Bahri
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
| | - Guillaume Becker
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
- Radiobiology Unit, SCK•CEN, Belgian Nuclear Research Centre, 2400, Mol, Belgium
| | - Alain Seret
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
| | | | - Christian Lemaire
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
| | - Fabrice Giacomelli
- Nucleis, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
| | - Frédéric Mievis
- Nucleis, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
| | - André Luxen
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
| | - Eric Salmon
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
- Neurology Department, CHU, Academic Hospital, University of Liège, 4000, Liège, Belgium
| | - Bernard Rogister
- Neurology Department, CHU, Academic Hospital, University of Liège, 4000, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Avenue Hippocrate, 15, 4000, Liège, Belgium
| | | | - Alain Plenevaux
- GIGA, CRC in vivo imaging, University of Liège, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liège, Belgium
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Becker G, Dammicco S, Bahri MA, Salmon E. The Rise of Synaptic Density PET Imaging. Molecules 2020; 25:molecules25102303. [PMID: 32422902 PMCID: PMC7288098 DOI: 10.3390/molecules25102303] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/08/2020] [Accepted: 05/08/2020] [Indexed: 11/16/2022] Open
Abstract
Many neurological disorders are related to synaptic loss or pathologies. Before the boom of positrons emission tomography (PET) imaging of synapses, synaptic quantification could only be achieved in vitro on brain samples after autopsy or surgical resections. Until the mid-2010s, electron microscopy and immunohistochemical labelling of synaptic proteins were the gold-standard methods for such analyses. Over the last decade, several PET radiotracers for the synaptic vesicle 2A protein have been developed to achieve in vivo synapses visualization and quantification. Different strategies were used, namely radiolabelling with either 11C or 18F, preclinical development in rodent and non-human primates, and binding quantification with different kinetic modelling methods. This review provides an overview of these PET tracers and underlines their perspectives and limitations by focusing on radiochemical aspects, as well as preclinical proof-of-concept and the main clinical outcomes described so far.
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Evaluating the In Vivo Specificity of [ 18F]UCB-H for the SV2A Protein, Compared with SV2B and SV2C in Rats Using microPET. Molecules 2019; 24:molecules24091705. [PMID: 31052478 PMCID: PMC6538996 DOI: 10.3390/molecules24091705] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/28/2019] [Accepted: 04/29/2019] [Indexed: 11/25/2022] Open
Abstract
The synaptic vesicle protein 2 (SV2) is involved in synaptic vesicle trafficking. The SV2A isoform is the most studied and its implication in epilepsy therapy led to the development of the first SV2A PET radiotracer [18F]UCB-H. The objective of this study was to evaluate in vivo, using microPET in rats, the specificity of [18F]UCB-H for SV2 isoform A in comparison with the other two isoforms (B and C) through a blocking assay. Twenty Sprague Dawley rats were pre-treated either with the vehicle, or with specific competitors against SV2A (levetiracetam), SV2B (UCB5203) and SV2C (UCB0949). The distribution volume (Vt, Logan plot, t* 15 min) was obtained with a population-based input function. The Vt analysis for the entire brain showed statistically significant differences between the levetiracetam group and the other groups (p < 0.001), but also between the vehicle and the SV2B group (p < 0.05). An in-depth Vt analysis conducted for eight relevant brain structures confirmed the statistically significant differences between the levetiracetam group and the other groups (p < 0.001) and highlighted the superior and the inferior colliculi along with the cortex as regions also displaying statistically significant differences between the vehicle and SV2B groups (p < 0.05). These results emphasize the in vivo specificity of [18F]UCB-H for SV2A against SV2B and SV2C, confirming that [18F]UCB-H is a suitable radiotracer for in vivo imaging of the SV2A proteins with PET.
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