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Chen L, Li X, Ge Y, Li H, Li R, Song X, Liang J, Zhang W, Li X, Wang X, Wang Y, Wu Y, Bai Y, Wang M. GMP-compliant automated radiosynthesis of [ 18F] SynVesT-1 for PET imaging of synaptic vesicle glycoprotein 2 A (SV2A). EJNMMI Radiopharm Chem 2024; 9:66. [PMID: 39254802 PMCID: PMC11387577 DOI: 10.1186/s41181-024-00284-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Accepted: 07/09/2024] [Indexed: 09/11/2024] Open
Abstract
BACKGROUND A novel positron emission tomography (PET) imaging tracer, [18F] SynVesT-1, targeting synaptic vesicle glycoprotein 2 (SV2A), has been developed to meet clinical demand. Utilizing the Trasis AllinOne-36 (AIO) module, we've automated synthesis to Good Manufacturing Practice (GMP) standards, ensuring sterile, pyrogen-free production. The fully GMP-compliant robust synthesis of [18F] SynVesT-1 boosting reliability and introducing a significant degree of simplicity and its comprehensive validation for routine human use. RESULTS [18F] SynVesT-1 was synthesized by small modifications to the original [18F] SynVesT-1 synthesis protocol to better fit AIO module using an in-house designed cassette and sequence. With a relatively small precursor load of 5 mg, [18F] SynVesT-1 was obtained with consistently high radiochemical yields (RCY) of 20.6 ± 1.2% (the decay-corrected RCY, n = 3) at end of synthesis. Each of the final formulated batches demonstrated radiochemical purity (RCP) and enantiomeric purity surpassing 99%. The entire synthesis process was completed within a timeframe of 80 min (75 ± 3.1 min, n = 3), saves 11 min compared to reported GMP automated synthesis procedures. The in-human PET imaging of total body PET/CT and time-of-flight (TOF) PET/MR showed that [18F] SynVesT-1 is an excellent tracer for SV2A. It is advantageous for decentralized promotion and application in multi-center studies. CONCLUSION The use of AIO synthesizer maintains high production yields and increases reliability, reduces production time and allows rapid training of production staff. Besides, the as-prepared [18F] SynVesT-1 displays excellent in vivo binding properties in humans and holds great potential for the imaging and quantification of synaptic density in vivo.
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Affiliation(s)
- Lijuan Chen
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Xiaochen Li
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Yao Ge
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Huiqiang Li
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Ruili Li
- School of Clinical Medicine, Henan University, Kaifeng, 475004, China
| | - Xiaosheng Song
- Institute of Biomedicine, Henan Academy of Sciences, Zhengzhou, 450046, China
| | | | - Weifeng Zhang
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Xiaona Li
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Xiaoqi Wang
- School of Clinical Medicine, Henan University, Kaifeng, 475004, China
| | - Yunjuan Wang
- Institute of Biomedicine, Henan Academy of Sciences, Zhengzhou, 450046, China
- School of life sciences, Henan University, Kaifeng, 475004, China
| | - Yaping Wu
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Yan Bai
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China
| | - Meiyun Wang
- Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China.
- Institute of Biomedicine, Henan Academy of Sciences, Zhengzhou, 450046, China.
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Luo X, Jin C, Chen H, Niu J, Yu C, Dou X, Wang J, Wen J, Zhang H, Tian M, Zhong Y. PET imaging of synaptic vesicle glycoprotein 2 subtype A for neurological recovery in ischemic stroke. Eur J Nucl Med Mol Imaging 2024:10.1007/s00259-024-06904-6. [PMID: 39196302 DOI: 10.1007/s00259-024-06904-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Accepted: 08/24/2024] [Indexed: 08/29/2024]
Abstract
PURPOSE [18F]SynVesT-1 is a novel radiopharmaceutical for assessing synaptic density in vivo. This study aims to investigate the potential of [18F]SynVesT-1 positron emission tomography (PET) in evaluating neurological recovery in the rat model of ischemic stroke, and to compare its performance with [18F]FDG PET. METHODS Sprague-Dawley rats were subjected to photothrombotic cerebral infarction, and safinamide was administered intraperitoneally from day 3 to day 14 post-stroke to alleviate neurological deficits. Cylinder test and forelimb placing test were performed to assess the neurological function. MRI, [18F]SynVesT-1 PET/CT and [18F]FDG PET/CT imaging were used to evaluate infarct volume, synaptic density, and cerebral glucose metabolism pre- and post-treatment. [18F]SynVesT-1 and [18F]FDG PET images were compared using Statistical Parametric Mapping (SPM) and region of interest (ROI)-based analysis. Post-mortem histological analysis was performed to validate PET images. RESULTS Safinamide treatment improved behavioral outcomes in stroke-damaged rats. Both [18F]SynVesT-1 and [18F]FDG PET detected stroke-induced injury, with the injured region being significantly larger in [18F]FDG PET than in [18F]SynVesT-1 PET. Compared with the saline group, radiotracer uptake in the injured area significantly increased in [18F]SynVesT-1 PET after safinamide treatment, whereas no notable change was observed in [18F]FDG PET. Additionally, [18F]SynVesT-1 PET imaging showed a better correlation with neurological function recovery than [18F]FDG PET. Post-mortem analysis revealed increased neuronal numbers, synaptic density, and synaptic neuroplasticity, as well as decreased glia activation in the stroke-injured area after treatment. CONCLUSION [18F]SynVesT-1 PET effectively quantified spatiotemporal dynamics of synaptic density in the rat model of stroke, and showed different capabilities in detecting stroke injury and neurological recovery compared with [18F]FDG PET. The utilization of [18F]SynVesT-1 PET holds promise as a potential non-invasive biomarker for evaluating ischemic stroke in conjunction with [18F]FDG PET.
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Affiliation(s)
- Xiaoyun Luo
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Chentao Jin
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, Zhejiang, 310014, China
| | - Hetian Chen
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Jiaqi Niu
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Congcong Yu
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Xiaofeng Dou
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Jing Wang
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Junjie Wen
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, 310014, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, Zhejiang, 310014, China
| | - Hong Zhang
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China.
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China.
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, 310014, China.
- Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, Zhejiang, 310014, China.
| | - Mei Tian
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China.
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China.
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.
- Human Phenome Institute, Fudan University, 825 Zhangheng Road, Shanghai, 201203, China.
| | - Yan Zhong
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, 310009, China.
- Institute of Nuclear Medicine and Molecular, Imaging of Zhejiang University, Hangzhou, Zhejiang, 310009, China.
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.
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Asch RH, Abdallah CG, Carson RE, Esterlis I. Challenges and rewards of in vivo synaptic density imaging, and its application to the study of depression. Neuropsychopharmacology 2024:10.1038/s41386-024-01913-3. [PMID: 39039139 DOI: 10.1038/s41386-024-01913-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/14/2024] [Accepted: 06/26/2024] [Indexed: 07/24/2024]
Abstract
The development of novel radiotracers for Positron Emission Tomography (PET) imaging agents targeting the synaptic vesicle glycoprotein 2 A (SV2A), an integral glycoprotein present in the membrane of all synaptic vesicles throughout the central nervous system, provides a method for the in vivo quantification of synaptic density. This is of particular interest in neuropsychiatric disorders given that synaptic alterations appear to underlie disease progression and symptom severity. In this review, we briefly describe the development of these SV2A tracers and the evaluation of quantification methods. Next, we discuss application of SV2A PET imaging to the study of depression, including a review of our findings demonstrating lower SV2A synaptic density in people with significant depressive symptoms and the use of a ketamine drug challenge to examine synaptogenesis in vivo. We then highlight the importance of performing translational PET imaging in animal models in conjunction with clinical imaging. We consider the ongoing challenges, possible solutions, and present preliminary findings from our lab demonstrating the translational benefit and potential of in vivo SV2A imaging in animal models of chronic stress. Finally, we discuss methodological improvements and future directions for SV2A imaging, potentially in conjunction with other neural markers.
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Affiliation(s)
- Ruth H Asch
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Chadi G Abdallah
- Menninger Department of Psychiatry & Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale School of Engineering, New Haven, CT, USA
| | - Irina Esterlis
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale School of Medicine, New Haven, CT, USA.
- U.S. Department of Veteran Affairs National Center for Posttraumatic Stress Disorder, Clinical Neurosciences Division, VA Connecticut Healthcare System, West Haven, CT, USA.
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4
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Liu H, Jiang M, Chen Z, Li C, Yin X, Zhang X, Wu M. The Role of the Complement System in Synaptic Pruning after Stroke. Aging Dis 2024:AD.2024.0373. [PMID: 39012667 DOI: 10.14336/ad.2024.0373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/25/2024] [Indexed: 07/17/2024] Open
Abstract
Stroke is a serious disease that can lead to local neurological dysfunction and cause great harm to the patient's health due to blood cerebral circulation disorder. Synaptic pruning is critical for the normal development of the human brain, which makes the synaptic circuit completer and more efficient by removing redundant synapses. The complement system is considered a key player in synaptic loss and cognitive impairment in neurodegenerative disease. After stroke, the complement system is over-activated, and complement proteins can be labeled on synapses. Microglia and astrocytes can recognize and engulf synapses through corresponding complement receptors. Complement-mediated excessive synaptic pruning can cause post-stroke cognitive impairment (PSCI) and secondary brain damage. This review summarizes the latest progress of complement-mediated synaptic pruning after stroke and the potential mechanisms. Targeting complement-mediated synaptic pruning may be essential for exploring therapeutic strategies for secondary brain injury (SBI) and neurological dysfunction after stroke.
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Affiliation(s)
- Hongying Liu
- Department of Medical Laboratory, Affiliated Hospital of Jiujiang University, Jiujiang, 332000, China
| | - Min Jiang
- Jiujiang Clinical Precision Medicine Research Center, Jiujiang, 332000, China
| | - Zhiying Chen
- Department of Neurology, Affiliated Hospital of Jiujiang University, Jiujiang 332000, China
| | - Chuan Li
- Department of Medical Laboratory, Affiliated Hospital of Jiujiang University, Jiujiang, 332000, China
| | - Xiaoping Yin
- Department of Neurology, Affiliated Hospital of Jiujiang University, Jiujiang 332000, China
| | - Xiaorong Zhang
- Jiujiang Clinical Precision Medicine Research Center, Jiujiang, 332000, China
| | - Moxin Wu
- Department of Medical Laboratory, Affiliated Hospital of Jiujiang University, Jiujiang, 332000, China
- Jiujiang Clinical Precision Medicine Research Center, Jiujiang, 332000, China
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5
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Li C, Jiang M, Fang Z, Chen Z, Li L, Liu Z, Wang J, Yin X, Wang J, Wu M. Current evidence of synaptic dysfunction after stroke: Cellular and molecular mechanisms. CNS Neurosci Ther 2024; 30:e14744. [PMID: 38727249 PMCID: PMC11084978 DOI: 10.1111/cns.14744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/07/2024] [Accepted: 04/10/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND Stroke is an acute cerebrovascular disease in which brain tissue is damaged due to sudden obstruction of blood flow to the brain or the rupture of blood vessels in the brain, which can prompt ischemic or hemorrhagic stroke. After stroke onset, ischemia, hypoxia, infiltration of blood components into the brain parenchyma, and lysed cell fragments, among other factors, invariably increase blood-brain barrier (BBB) permeability, the inflammatory response, and brain edema. These changes lead to neuronal cell death and synaptic dysfunction, the latter of which poses a significant challenge to stroke treatment. RESULTS Synaptic dysfunction occurs in various ways after stroke and includes the following: damage to neuronal structures, accumulation of pathologic proteins in the cell body, decreased fluidity and release of synaptic vesicles, disruption of mitochondrial transport in synapses, activation of synaptic phagocytosis by microglia/macrophages and astrocytes, and a reduction in synapse formation. CONCLUSIONS This review summarizes the cellular and molecular mechanisms related to synapses and the protective effects of drugs or compounds and rehabilitation therapy on synapses in stroke according to recent research. Such an exploration will help to elucidate the relationship between stroke and synaptic damage and provide new insights into protecting synapses and restoring neurologic function.
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Affiliation(s)
- Chuan Li
- Department of Medical LaboratoryAffiliated Hospital of Jiujiang UniversityJiujiangJiangxiChina
| | - Min Jiang
- Jiujiang Clinical Precision Medicine Research CenterJiujiangJiangxiChina
| | - Zhi‐Ting Fang
- Department of Pathophysiology, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubeiChina
| | - Zhiying Chen
- Department of NeurologyAffiliated Hospital of Jiujiang UniversityJiujiangJiangxiChina
| | - Li Li
- Department of Intensive Care UnitThe Affiliated Hospital of Jiujiang UniversityJiujiangJiangxiChina
| | - Ziying Liu
- Department of Medical LaboratoryAffiliated Hospital of Jiujiang UniversityJiujiangJiangxiChina
| | - Junmin Wang
- Department of Human Anatomy, School of Basic Medical SciencesZhengzhou UniversityZhengzhouHenanChina
| | - Xiaoping Yin
- Department of NeurologyAffiliated Hospital of Jiujiang UniversityJiujiangJiangxiChina
| | - Jian Wang
- Department of Human Anatomy, School of Basic Medical SciencesZhengzhou UniversityZhengzhouHenanChina
| | - Moxin Wu
- Department of Medical LaboratoryAffiliated Hospital of Jiujiang UniversityJiujiangJiangxiChina
- Jiujiang Clinical Precision Medicine Research CenterJiujiangJiangxiChina
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Laroy M, Vande Casteele T, Van Cauwenberge M, Koole M, Dupont P, Sunaert S, Van den Stock J, Sienaert P, Van Laere K, Vandenbulcke M, Emsell L, Bouckaert F. Synaptic density changes following electroconvulsive therapy: A longitudinal pilot study with PET-MR 11C-UCB-J imaging in late-life depression. Brain Stimul 2024; 17:588-590. [PMID: 38701916 DOI: 10.1016/j.brs.2024.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 04/30/2024] [Indexed: 05/05/2024] Open
Affiliation(s)
- Maarten Laroy
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium.
| | - Thomas Vande Casteele
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
| | - Margot Van Cauwenberge
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium; Department of Neurology, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - Michel Koole
- KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Nuclear Medicine, B-3000, Leuven, Belgium
| | - Patrick Dupont
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Laboratory for Cognitive Neurology, B-3000, Leuven, Belgium
| | - Stefan Sunaert
- KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Translational MRI, B-3000, Leuven, Belgium; Department of Radiology, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - Jan Van den Stock
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium; Geriatric Psychiatry, University Psychiatric Centre KU Leuven, B-3000, Leuven, Belgium
| | - Pascal Sienaert
- KU Leuven, Department of Neurosciences, Academic Centre for ECT and Neuromodulation, B-3000, Leuven, Belgium
| | - Koen Van Laere
- Department of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - Mathieu Vandenbulcke
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium; Geriatric Psychiatry, University Psychiatric Centre KU Leuven, B-3000, Leuven, Belgium
| | - Louise Emsell
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium; KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Translational MRI, B-3000, Leuven, Belgium; Geriatric Psychiatry, University Psychiatric Centre KU Leuven, B-3000, Leuven, Belgium
| | - Filip Bouckaert
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium; Geriatric Psychiatry, University Psychiatric Centre KU Leuven, B-3000, Leuven, Belgium
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7
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Vande Casteele T, Laroy M, Van Cauwenberge M, Koole M, Dupont P, Sunaert S, Van den Stock J, Bouckaert F, Van Laere K, Emsell L, Vandenbulcke M. Preliminary evidence for preserved synaptic density in late-life depression. Transl Psychiatry 2024; 14:145. [PMID: 38485934 PMCID: PMC10940592 DOI: 10.1038/s41398-024-02837-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 03/18/2024] Open
Abstract
Late-life depression has been consistently associated with lower gray matter volume, the origin of which remains largely unexplained. Recent in-vivo PET findings in early-onset depression and Alzheimer's Disease suggest that synaptic deficits contribute to the pathophysiology of these disorders and may therefore contribute to lower gray matter volume in late-life depression. Here, we investigate synaptic density in vivo for the first time in late-life depression using the synaptic vesicle glycoprotein 2A receptor radioligand 11C-UCB-J. We included 24 currently depressed adults with late-life depression (73.0 ± 6.2 years, 16 female, geriatric depression scale = 19.5 ± 6.8) and 36 age- and gender-matched healthy controls (70.4 ± 6.2 years, 21 female, geriatric depression scale = 2.7 ± 2.9) that underwent simultaneous 11C-UCB-J positron emission tomography (PET) and 3D T1- and T2-FLAIR weighted magnetic resonance (MR) imaging on a 3-tesla PET-MR scanner. We used analyses of variance to test for 11C-UCB-J binding and gray matter volumes differences in regions implicated in depression. The late-life depression group showed a trend in lower gray matter volumes in the hippocampus (p = 0.04), mesial temporal (p = 0.02) and prefrontal cortex (p = 0.02) compared to healthy control group without surviving correction for multiple comparison. However, no group differences in 11C-UCB-J binding were found in these regions nor were any associations between 11C-UCB-J and depressive symptoms. Our data suggests that, in contrast to Alzheimer's Disease, lower gray matter volume in late-life depression is not associated with synaptic density changes. From a therapeutic standpoint, preserved synaptic density in late-life depression may be an encouraging finding.
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Affiliation(s)
- Thomas Vande Casteele
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium.
| | - Maarten Laroy
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
| | - Margot Van Cauwenberge
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
- Neurology, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - Michel Koole
- KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Nuclear Medicine, B-3000, Leuven, Belgium
| | - Patrick Dupont
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Laboratory for Cognitive Neurology, B-3000, Leuven, Belgium
| | - Stefan Sunaert
- KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Translational MRI, B-3000, Leuven, Belgium
- Radiology, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - Jan Van den Stock
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, B-3000, Leuven, Belgium
| | - Filip Bouckaert
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, B-3000, Leuven, Belgium
| | - Koen Van Laere
- KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Nuclear Medicine, B-3000, Leuven, Belgium
- Nuclear Medicine, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - Louise Emsell
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
- KU Leuven, Leuven Brain Institute, Department of Imaging and Pathology, Translational MRI, B-3000, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, B-3000, Leuven, Belgium
| | - Mathieu Vandenbulcke
- KU Leuven, Leuven Brain Institute, Department of Neurosciences, Neuropsychiatry, B-3000, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, B-3000, Leuven, Belgium
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8
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Fan XY, Shi G, Zhao YP, Yang JJ, Feng J. Neuroprotective effects of oxytocin against ischemic stroke in rats by blocking glutamate release and CREB-mediated DNA hypermethylation. Biomed Pharmacother 2023; 167:115520. [PMID: 37729734 DOI: 10.1016/j.biopha.2023.115520] [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: 08/01/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023] Open
Abstract
Glutamate plays a crucial role in cognitive impairments after ischemic stroke. There is a scarcity of information about how glutamate-induced activation of cAMP-response element binding (CREB) signaling pathway regulates both the negative and positive regulators of synaptic plasticity. Recent studies have demonstrated the involvement of prominent epigenetic repressors, such as MeCP2 and DNMTs, in stroke. Neuroprotective effects of oxytocin against ischemia have been previously reported, while the underlying mechanism is still elusive. In this research, the possible role of CREB-mediated DNA hypermethylation and the potential mechanism of oxytocin in a rat model of permanent middle cerebral artery occlusion (pMCAO) were assessed. Adult male Sprague-Dawley rats were pretreated with intraperitoneal injection of oxytocin at the onset of pMCAO. The effects of oxytocin on spines and the expression levels of synaptic genes were determined. The regulatory effects of oxytocin on glutamate level, N-methyl-D-aspartate receptors (NMDARs), its downstream CREB pathway, and global or gene-specific DNA methylation status were evaluated by immunofluorescence, co-immunoprecipitation, and chromatin immunoprecipitation, respectively. We found that CREB could act as a common transcription factor for MeCP2 and DNMT3B after ischemic stroke. Oxytocin dose-dependently deactivated NR2B-related CaM-CREB pathway and inhibited DNA hypermethylation at the CpG islands of Ngf gene in pMCAO-operated rats. Moreover, oxytocin prevented pMCAO-induced reduction in the number of spines and neural cells. DNA hypermethylation in Ngf gene contributed to the cognitive deficits post-stroke. The neuroprotective effects of oxytocin against ischemia could be attributed to inhibiting glutamate release, providing additional evidence on the mechanism of oxytocin against ischemic stroke.
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Affiliation(s)
- Xin-Yu Fan
- Department of Pharmacy, Shengjing Hospital of China Medical University, Shenyang, China
| | - Guang Shi
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, China; Department of Neurology, The People's Hospital of Liaoning Province, Shenyang, China
| | - Yun-Peng Zhao
- Department of Pharmacy, Shengjing Hospital of China Medical University, Shenyang, China
| | - Jing-Jing Yang
- Department of Pharmacy, Shengjing Hospital of China Medical University, Shenyang, China
| | - Juan Feng
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, China.
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9
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Van Cauwenberge MGA, Delva A, Vande Casteele T, Laroy M, Radwan A, Vansteelandt K, Van den Stock J, Bouckaert F, Van Laere K, Emsell L, Vandenberghe W, Vandenbulcke M. Mild Motor Signs in Healthy Aging Are Associated with Lower Synaptic Density in the Brain. Mov Disord 2023; 38:1786-1794. [PMID: 37574924 DOI: 10.1002/mds.29570] [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: 04/18/2023] [Revised: 06/17/2023] [Accepted: 07/17/2023] [Indexed: 08/15/2023] Open
Abstract
OBJECTIVE To investigate whether mild motor signs (MMS) in old age correlate with synaptic density in the brain. BACKGROUND Normal aging is associated with a decline in movement quality and quantity, commonly termed "mild parkinsonian signs" or more recently MMS. Whether MMS stem from global brain aging or pathology within motor circuits remains unresolved. The synaptic vesicle glycoprotein 2A positron emission tomography (PET) ligand 11 C-UCB-J allows the investigation of brain-motor associations at the synaptic level in vivo. METHOD Fifty-eight healthy older adults (≥50 years) were included from two monocentric control cohorts. Brain magnetic resonance imaging and 11 C-UCB-J PET data were available in 54 participants. 11 C-UCB-J PET binding was quantified by standardized uptake value ratio (SUVR) values in grey matter (GM) volumes of interest (VOIs): caudate, putamen, globus pallidus, substantia nigra, thalamus, cerebellum, and the frontal, parietal, temporal, and occipital cortex. Multiple linear regression analyses were performed with Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III score measuring MMS as the dependent variable and mean SUVR values in each VOI as the independent variable with age, Fazekas score (white matter lesion [WML] load), VOI and cohort as covariates. RESULTS Participants (68 ± 7.5 years; 52% female) had an average MDS-UPDRS part III score of 3.3 ± 2.8. The MDS-UPDRS part III score was inversely associated with synaptic density, independently of WML load or GM volume, in the caudate, substantia nigra, thalamus, cerebellum, and parietal, occipital, temporal cortex. Cohen's f2 showed moderate effect sizes for subcortical (range, 0.30-0.35), cortical (0.28-0.35) and cerebellar VOIs (0.31). CONCLUSION MMS in healthy aging are associated with lower synaptic density throughout the brain. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Margot G A Van Cauwenberge
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Aline Delva
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Laboratory for Parkinson Research, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Thomas Vande Casteele
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium
| | - Maarten Laroy
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Ahmed Radwan
- Department of Imaging and Pathology, Translational MRI, KU Leuven, Leuven, Belgium
- Department of Radiology, University Hospitals Leuven, Leuven, Belgium
| | - Kristof Vansteelandt
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Jan Van den Stock
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium
| | - Filip Bouckaert
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Division of Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium
- Department of Imaging and Pathology, Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium
| | - Louise Emsell
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium
- Department of Imaging and Pathology, Translational MRI, KU Leuven, Leuven, Belgium
| | - Wim Vandenberghe
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Laboratory for Parkinson Research, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- Department of Neurosciences, Neuropsychiatry, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Geriatric Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium
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10
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Zhang J, Wang J, Xu X, You Z, Huang Q, Huang Y, Guo Q, Guan Y, Zhao J, Liu J, Xu W, Deng Y, Xie F, Li B. In vivo synaptic density loss correlates with impaired functional and related structural connectivity in Alzheimer's disease. J Cereb Blood Flow Metab 2023; 43:977-988. [PMID: 36718002 PMCID: PMC10196742 DOI: 10.1177/0271678x231153730] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 12/29/2022] [Accepted: 01/02/2023] [Indexed: 02/01/2023]
Abstract
Synapse loss has been considered as a major pathological change in Alzheimer's disease (AD). It remains unclear about whether and how synapse loss relates to functional and structural connectivity dysfunction in AD. We measured synaptic vesicle glycoprotein 2 A (SV2A) binding using 18F-SynVesT-1 PET to evaluate synaptic alterations in 33 participants with AD, 31 with mild cognitive impairment (MCI), and 30 controls. We examined the correlation between synaptic density and cognitive function. Functional MRI was performed to analyze functional connectivity in lower synaptic density regions. We tracked the white matter tracts between impaired functional connectivity regions using Diffusion MRI. In AD group, lower synaptic density in bilateral cortex and hippocampus was found when compared with controls. The synaptic density changes in right insular cortex and bilateral caudal middle frontal gyrus (MFG) were correlated with cognitive decline. Among them, right MFG synaptic density was positively associated with right MFG - bilateral superior frontal gyrus (SFG) functional connectivity. AD had lower probability of tract (POT) between right MFG and SFG than controls, which was significantly associated with global cognition. These findings provide evidence supporting synapse loss contributes to functional and related structural connectivity alterations underlying cognitive impairment of AD.
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Affiliation(s)
- Junfang Zhang
- Department of Neurology and
Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China
| | - Jie Wang
- Department of Nuclear Medicine
& PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaomeng Xu
- Department of Neurology and
Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China
| | - Zhiwen You
- Department of Nuclear Medicine,
Shanghai East Hospital, Tongji University School of Medicine, Shanghai,
China
| | - Qi Huang
- Department of Nuclear Medicine
& PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Yiyun Huang
- PET Center, Department of Radiology
and Biomedical Imaging, Yale University School of Medicine, New Haven,
Connecticut, USA
| | - Qihao Guo
- Department of Gerontology, Shanghai
Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Yihui Guan
- Department of Nuclear Medicine
& PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Jun Zhao
- Department of Nuclear Medicine,
Shanghai East Hospital, Tongji University School of Medicine, Shanghai,
China
| | - Jun Liu
- Department of Neurology and
Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China
- Clinical Neuroscience Center,
Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai,
China
| | - Wei Xu
- Department of Neurology and
Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China
| | - Yulei Deng
- Department of Neurology and
Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China
- Clinical Neuroscience Center,
Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai,
China
- Department of Neurology, Ruijin
Hospital LuWan Branch, Shanghai Jiao Tong University School of Medicine,
Shanghai, China
| | - Fang Xie
- Department of Nuclear Medicine
& PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Binyin Li
- Department of Neurology and
Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China
- Clinical Neuroscience Center,
Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai,
China
- Department of Neurology, Ruijin
Hospital LuWan Branch, Shanghai Jiao Tong University School of Medicine,
Shanghai, China
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11
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Chi X, Wang L, Liu H, Zhang Y, Shen W. Post-stroke cognitive impairment and synaptic plasticity: A review about the mechanisms and Chinese herbal drugs strategies. Front Neurosci 2023; 17:1123817. [PMID: 36937659 PMCID: PMC10014821 DOI: 10.3389/fnins.2023.1123817] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Post-stroke cognitive impairment, is a major complication of stroke, characterized by cognitive dysfunction, which directly affects the quality of life. Post-stroke cognitive impairment highlights the causal relationship between stroke and cognitive impairment. The pathological damage of stroke, including the increased release of excitatory amino acids, oxidative stress, inflammatory responses, apoptosis, changed neurotrophic factor levels and gene expression, influence synaptic plasticity. Synaptic plasticity refers to the activity-dependent changes in the strength of synaptic connections and efficiency of synaptic transmission at pre-existing synapses and can be divided into structural synaptic plasticity and functional synaptic plasticity. Changes in synaptic plasticity have been proven to play important roles in the occurrence and treatment of post-stroke cognitive impairment. Evidence has indicated that Chinese herbal drugs have effect of treating post-stroke cognitive impairment. In this review, we overview the influence of pathological damage of stroke on synaptic plasticity, analyze the changes of synaptic plasticity in post-stroke cognitive impairment, and summarize the commonly used Chinese herbal drugs whose active ingredient or extracts can regulate synaptic plasticity. This review will summarize the relationship between post-stroke cognitive impairment and synaptic plasticity, provide new ideas for future exploration of the mechanism of post-stroke cognitive impairment, compile evidence of applying Chinese herbal drugs to treat post-stroke cognitive impairment and lay a foundation for the development of novel formulas for treating post-stroke cognitive impairment.
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Affiliation(s)
- Xiansu Chi
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Liuding Wang
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hongxi Liu
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Yunling Zhang
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wei Shen
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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12
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Michiels L, Thijs L, Mertens N, Coremans M, Vandenbulcke M, Verheyden G, Koole M, Van Laere K, Lemmens R. Longitudinal Synaptic Density PET with 11 C-UCB-J 6 Months After Ischemic Stroke. Ann Neurol 2022; 93:911-921. [PMID: 36585914 DOI: 10.1002/ana.26593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/30/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The purpose of this study was to explore longitudinal changes in synaptic density after ischemic stroke in vivo with synaptic vesicle protein 2A (SV2A) positron emission tomography (PET). METHODS We recruited patients with an ischemic stroke to undergo 11 C-UCB-J PET/MR within the first month and 6 months after the stroke. We investigated longitudinal changes of partial volume corrected 11 C-UCB-J standardized uptake value ratio (SUVR; relative to centrum semiovale) within the ischemic lesion, peri-ischemic area and unaffected ipsilesional and contralesional grey matter. We also explored crossed cerebellar diaschisis at 6 months. Additionally, we defined brain regions potentially influencing upper limb motor recovery after stroke and studied 11 C-UCB-J SUVR evolution in comparison to baseline. RESULTS In 13 patients (age = 67 ± 15 years) we observed decreasing 11 C-UCB-J SUVR in the ischemic lesion (ΔSUVR = -1.0, p = 0.001) and peri-ischemic area (ΔSUVR = -0.31, p = 0.02) at 6 months after stroke compared to baseline. Crossed cerebellar diaschisis as measured with 11 C-UCB-J SUVR was present in 11 of 13 (85%) patients at 6 months. The 11 C-UCB-J SUVR did not augment in ipsilesional or contralesional brain regions associated with motor recovery. On the contrary, there was an overall trend of declining 11 C-UCB-J SUVR in these brain regions, reaching statistical significance only in the nonlesioned part of the ipsilesional supplementary motor area (ΔSUVR = -0.83, p = 0.046). INTERPRETATION At 6 months after stroke, synaptic density further declined in the ischemic lesion and peri-ischemic area compared to baseline. Brain regions previously demonstrated to be associated with motor recovery after stroke did not show increases in synaptic density. ANN NEUROL 2023.
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Affiliation(s)
- Laura Michiels
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| | - Liselot Thijs
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Marjan Coremans
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium.,Department of Geriatric Psychiatry, University Psychiatric Centre, Leuven, Belgium
| | - Geert Verheyden
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Leuven Brain Institute, Leuven, Belgium.,Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,Department of Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
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13
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Excitatory Synaptic Transmission in Ischemic Stroke: A New Outlet for Classical Neuroprotective Strategies. Int J Mol Sci 2022; 23:ijms23169381. [PMID: 36012647 PMCID: PMC9409263 DOI: 10.3390/ijms23169381] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 01/01/2023] Open
Abstract
Stroke is one of the leading causes of death and disability in the world, of which ischemia accounts for the majority. There is growing evidence of changes in synaptic connections and neural network functions in the brain of stroke patients. Currently, the studies on these neurobiological alterations mainly focus on the principle of glutamate excitotoxicity, and the corresponding neuroprotective strategies are limited to blocking the overactivation of ionic glutamate receptors. Nevertheless, it is disappointing that these treatments often fail because of the unspecificity and serious side effects of the tested drugs in clinical trials. Thus, in the prevention and treatment of stroke, finding and developing new targets of neuroprotective intervention is still the focus and goal of research in this field. In this review, we focus on the whole processes of glutamatergic synaptic transmission and highlight the pathological changes underlying each link to help develop potential therapeutic strategies for ischemic brain damage. These strategies include: (1) controlling the synaptic or extra-synaptic release of glutamate, (2) selectively blocking the action of the glutamate receptor NMDAR subunit, (3) increasing glutamate metabolism, and reuptake in the brain and blood, and (4) regulating the glutamate system by GABA receptors and the microbiota–gut–brain axis. Based on these latest findings, it is expected to promote a substantial understanding of the complex glutamate signal transduction mechanism, thereby providing excellent neuroprotection research direction for human ischemic stroke (IS).
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14
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Carson RE, Naganawa M, Toyonaga T, Koohsari S, Yang Y, Chen MK, Matuskey D, Finnema SJ. Imaging of Synaptic Density in Neurodegenerative Disorders. J Nucl Med 2022; 63:60S-67S. [PMID: 35649655 DOI: 10.2967/jnumed.121.263201] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/10/2022] [Indexed: 02/07/2023] Open
Abstract
PET technology has produced many radiopharmaceuticals that target specific brain proteins and other measures of brain function. Recently, a new approach has emerged to image synaptic density by targeting the synaptic vesicle protein 2A (SV2A), an integral glycoprotein in the membrane of synaptic vesicles and widely distributed throughout the brain. Multiple SV2A ligands have been developed and translated to human use. The most successful of these to date is 11C-UCB-J, because of its high uptake, moderate metabolism, and effective quantification with a 1-tissue-compartment model. Further, since SV2A is the target of the antiepileptic drug levetiracetam, human blocking studies have characterized specific binding and potential reference regions. Regional brain SV2A levels were shown to correlate with those of synaptophysin, another commonly used marker of synaptic density, providing the basis for SV2A PET imaging to have broad utility across neuropathologic diseases. In this review, we highlight the development of SV2A tracers and the evaluation of quantification methods, including compartment modeling and simple tissue ratios. Mouse and rat models of neurodegenerative diseases have been studied with small-animal PET, providing validation by comparison to direct tissue measures. Next, we review human PET imaging results in multiple neurodegenerative disorders. Studies on Parkinson disease and Alzheimer disease have progressed most rapidly at multiple centers, with generally consistent results of patterns of SV2A or synaptic loss. In Alzheimer disease, the synaptic loss patterns differ from those of amyloid, tau, and 18F-FDG, although intertracer and interregional correlations have been found. Smaller studies have been reported in other disorders, including Lewy body dementia, frontotemporal dementia, Huntington disease, progressive supranuclear palsy, and corticobasal degeneration. In conclusion, PET imaging of SV2A has rapidly developed, and qualified radioligands are available. PET studies on humans indicate that SV2A loss might be specific to disease-associated brain regions and consistent with synaptic density loss. The recent availability of new 18F tracers, 18F-SynVesT-1 and 18F-SynVesT-2, will substantially broaden the application of SV2A PET. Future studies are needed in larger patient cohorts to establish the clinical value of SV2A PET and its potential for diagnosis and progression monitoring of neurodegenerative diseases, as well as efficacy assessment of disease-modifying therapies.
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Affiliation(s)
- Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut;
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Mika Naganawa
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut
| | - Takuya Toyonaga
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut
| | - Sheida Koohsari
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut
| | - Yanghong Yang
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut
| | - Ming-Kai Chen
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale Positron Emission Tomography Center, Yale University, New Haven, Connecticut
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut; and
| | - Sjoerd J Finnema
- Neuroscience Discovery Research, Translational Imaging, AbbVie, North Chicago, Illinois
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15
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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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