1
|
Xiong M, Lubberink M, Appel L, Fang XT, Danfors T, Kumlien E, Antoni G. Evaluation of [ 11C]UCB-A positron emission tomography in human brains. EJNMMI Res 2024; 14:56. [PMID: 38884834 PMCID: PMC11183037 DOI: 10.1186/s13550-024-01117-2] [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: 03/25/2024] [Accepted: 06/02/2024] [Indexed: 06/18/2024] Open
Abstract
BACKGROUND In preclinical studies, the positron emission tomography (PET) imaging with [11C]UCB-A provided promising results for imaging synaptic vesicle protein 2A (SV2A) as a proxy for synaptic density. This paper reports the first-in-human [11C]UCB-A PET study to characterise its kinetics in healthy subjects and further evaluate SV2A-specific binding. RESULTS Twelve healthy subjects underwent 90-min baseline [11C]UCB-A scans with PET/MRI, with two subjects participating in an additional blocking scan with the same scanning procedure after a single dose of levetiracetam (1500 mg). Our results indicated abundant [11C]UCB-A brain uptake across all cortical regions, with slow elimination. Kinetic modelling of [11C]UCB-A PET using various compartment models suggested that the irreversible two-tissue compartment model best describes the kinetics of the radioactive tracer. Accordingly, the Patlak graphical analysis was used to simplify the analysis. The estimated SV2A occupancy determined by the Lassen plot was around 66%. Significant specific binding at baseline and comparable binding reduction as grey matter precludes the use of centrum semiovale as reference tissue. CONCLUSIONS [11C]UCB-A PET imaging enables quantifying SV2A in vivo. However, its slow kinetics require a long scan duration, which is impractical with the short half-life of carbon-11. Consequently, the slow kinetics and complicated quantification methods may restrict its use in humans.
Collapse
Affiliation(s)
- Mengfei Xiong
- Molecular Imaging and Medical Physics, Department of Surgical Sciences, Uppsala University, Entrance 70, 75185, Uppsala, Sweden.
| | - Mark Lubberink
- Molecular Imaging and Medical Physics, Department of Surgical Sciences, Uppsala University, Entrance 70, 75185, Uppsala, Sweden
| | - Lieuwe Appel
- Molecular Imaging and Medical Physics, Department of Surgical Sciences, Uppsala University, Entrance 70, 75185, Uppsala, Sweden
| | - Xiaotian Tsong Fang
- Molecular Imaging and Medical Physics, Department of Surgical Sciences, Uppsala University, Entrance 70, 75185, Uppsala, Sweden
- Julius Clinical BV, Zeist, The Netherlands
| | - Torsten Danfors
- Molecular Imaging and Medical Physics, Department of Surgical Sciences, Uppsala University, Entrance 70, 75185, Uppsala, Sweden
| | - Eva Kumlien
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Gunnar Antoni
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| |
Collapse
|
2
|
Yang Y, Zheng C, Chen B, Hernandez NC, Faust PL, Cai Z, Louis ED, Matuskey D. Decreased Synaptic Vesicle Glycoprotein 2A Binding in the Human Postmortem Essential Tremor Cerebellum: Evidence of Reduction in Synaptic Density. CEREBELLUM (LONDON, ENGLAND) 2024; 23:1053-1060. [PMID: 37783917 DOI: 10.1007/s12311-023-01611-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/27/2023] [Indexed: 10/04/2023]
Abstract
OBJECTIVE Despite being one of the most prevalent neurological diseases, the pathophysiology of essential tremor (ET) is not fully understood. Neuropathological studies have identified numerous degenerative changes in the cerebellum of ET patients, however. These data align with considerable clinical and neurophysiological data linking ET to the cerebellum. While neuroimaging studies have variably shown mild atrophy in the cerebellum, marked atrophy is not a clear feature of the cerebellum in ET and a search for a more suitable neuroimaging signature of neurodegeneration is in order. Postmortem studies in ET have examined different neuropathological alterations in the cerebellum, but as of yet have not focused on measures of generalized synaptic markers. This pilot study focuses on synaptic vesicle glycoprotein 2A (SV2A), a protein expressed in practically all synapses in the brain, as a measure of synaptic density in postmortem ET cases. METHODS The current study utilized autoradiography with the SV2A radioligand [18F]SDM-16 to assess synaptic density in the cerebellar cortex and dentate nucleus in three ET cases and three age-matched controls. RESULTS Using [18F]SDM-16, SV2A was 53% and 46% lower in the cerebellar cortex and dentate nucleus, respectively, in ET cases compared to age-matched controls. CONCLUSION In this pilot study, using in vitro SV2A autoradiography, we have observed significantly lower synaptic density in the cerebellar cortex and dentate nucleus of ET cases. Future research could expand on our sample size and focus on in vivo imaging in ET to explore whether SV2A imaging could serve as a much-needed disease biomarker.
Collapse
Affiliation(s)
- Yanghong Yang
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Chao Zheng
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Baosheng Chen
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Nora C Hernandez
- Department of Neurology, University of Texas Southwestern School of Medicine, Dallas, TX, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons and the New York Presbyterian Hospital, New York, NY, USA
| | - Zhengxin Cai
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern School of Medicine, Dallas, TX, USA
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.
| |
Collapse
|
3
|
Sun Y, Rodríguez-Rangel S, Zhang LL, Sánchez-Rodríguez JE, Brugarolas P. Chemical and biophysical characterization of novel potassium channel blocker 3-fluoro-5-methylpyridin-4-amine. Sci Rep 2024; 14:11105. [PMID: 38750155 PMCID: PMC11096398 DOI: 10.1038/s41598-024-61465-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 05/06/2024] [Indexed: 05/18/2024] Open
Abstract
4-aminopyridine (4AP) is a potassium (K+) channel blocker used clinically to improve walking in people with multiple sclerosis (MS). 4AP binds to exposed K+ channels in demyelinated axons, reducing the leakage of intracellular K+ and enhancing impulse conduction. Multiple derivatives of 4AP capable of blocking K+ channels have been reported including three radiolabeled with positron emitting isotopes for imaging demyelinated lesions using positron emission tomography (PET). However, there remains a demand for novel molecules with suitable physicochemical properties and binding affinity that can potentially be radiolabeled and used as PET radiotracers. In this study, we introduce 3-fluoro-5-methylpyridin-4-amine (5Me3F4AP) as a novel trisubstituted K+ channel blocker with potential application in PET. 5Me3F4AP has comparable potency to 4AP and the PET tracer 3-fluoro-4-aminopyridine (3F4AP). Compared to 3F4AP, 5Me3F4AP exhibits comparable basicity (pKa = 7.46 ± 0.01 vs. 7.37 ± 0.07, P-value = 0.08), greater lipophilicity (logD = 0.664 ± 0.005 vs. 0.414 ± 0.002, P-value < 0.0001) and higher permeability to an artificial brain membrane (Pe = 88.1 ± 18.3 vs. 31.1 ± 2.9 nm/s, P-value = 0.03). 5Me3F4AP is also more stable towards oxidation in vitro by the cytochrome P450 enzyme CYP2E1 (IC50 = 36.2 ± 2.5 vs. 15.4 ± 5.1, P-value = 0.0003); the enzyme responsible for the metabolism of 4AP and 3F4AP. Taken together, 5Me3F4AP has promising properties as a candidate for PET imaging warranting additional investigation.
Collapse
Affiliation(s)
- Yang Sun
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | | | - Lauren L Zhang
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | | | - Pedro Brugarolas
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA.
| |
Collapse
|
4
|
Bavarsad MS, Grinberg LT. SV2A PET imaging in human neurodegenerative diseases. Front Aging Neurosci 2024; 16:1380561. [PMID: 38699560 PMCID: PMC11064927 DOI: 10.3389/fnagi.2024.1380561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 05/05/2024] Open
Abstract
This manuscript presents a thorough review of synaptic vesicle glycoprotein 2A (SV2A) as a biomarker for synaptic integrity using Positron Emission Tomography (PET) in neurodegenerative diseases. Synaptic pathology, characterized by synaptic loss, has been linked to various brain diseases. Therefore, there is a need for a minimally invasive approach to measuring synaptic density in living human patients. Several radiotracers targeting synaptic vesicle protein 2A (SV2A) have been created and effectively adapted for use in human subjects through PET scans. SV2A is an integral glycoprotein found in the membranes of synaptic vesicles in all synaptic terminals and is widely distributed throughout the brain. The review delves into the development of SV2A-specific PET radiotracers, highlighting their advancements and limitations in neurodegenerative diseases. Among these tracers, 11C-UCB-J is the most used so far. We summarize and discuss an increasing body of research that compares measurements of synaptic density using SV2A PET with other established indicators of neurodegenerative diseases, including cognitive performance and radiological findings, thus providing a comprehensive analysis of SV2A's effectiveness and reliability as a diagnostic tool in contrast to traditional markers. Although the literature overall suggests the promise of SV2A as a diagnostic and therapeutic monitoring tool, uncertainties persist regarding the superiority of SV2A as a biomarker compared to other available markers. The review also underscores the paucity of studies characterizing SV2A distribution and loss in human brain tissue from patients with neurodegenerative diseases, emphasizing the need to generate quantitative neuropathological maps of SV2A density in cases with neurodegenerative diseases to fully harness the potential of SV2A PET imaging in clinical settings. We conclude by outlining future research directions, stressing the importance of integrating SV2A PET imaging with other biomarkers and clinical assessments and the need for longitudinal studies to track SV2A changes throughout neurodegenerative disease progression, which could lead to breakthroughs in early diagnosis and the evaluation of new treatments.
Collapse
Affiliation(s)
| | - Lea T. Grinberg
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco (UCSF), San Francisco, CA, United States
| |
Collapse
|
5
|
Kong Y, Cao L, Xie F, Wang X, Zuo C, Shi K, Rominger A, Huang Q, Xiao J, Jiang D, Guan Y, Ni R. Reduced SV2A and GABA A receptor levels in the brains of type 2 diabetic rats revealed by [ 18F]SDM-8 and [ 18F]flumazenil PET. Biomed Pharmacother 2024; 172:116252. [PMID: 38325265 DOI: 10.1016/j.biopha.2024.116252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/19/2023] [Accepted: 02/02/2024] [Indexed: 02/09/2024] Open
Abstract
PURPOSE Type 2 diabetes mellitus (T2DM) is associated with a greater risk of Alzheimer's disease. Synaptic impairment and protein aggregates have been reported in the brains of T2DM models. Here, we assessed whether neurodegenerative changes in synaptic vesicle 2 A (SV2A), γ-aminobutyric acid type A (GABAA) receptor, amyloid-β, tau and receptor for advanced glycosylation end product (RAGE) can be detected in vivo in T2DM rats. METHODS Positron emission tomography (PET) using [18F]SDM-8 (SV2A), [18F]flumazenil (GABAA receptor), [18F]florbetapir (amyloid-β), [18F]PM-PBB3 (tau), and [18F]FPS-ZM1 (RAGE) was carried out in 12-month-old diabetic Zucker diabetic fatty (ZDF) and SpragueDawley (SD) rats. Immunofluorescence staining, Thioflavin S staining, proteomic profiling and pathway analysis were performed on the brain tissues of ZDF and SD rats. RESULTS Reduced cortical [18F]SDM-8 uptake and cortical and hippocampal [18F]flumazenil uptake were observed in 12-month-old ZDF rats compared to SD rats. The regional uptake of [18F]florbetapir and [18F]PM-PBB3 was comparable in the brains of 12-month-old ZDF and SD rats. Immunofluorescence staining revealed Thioflavin S-negative, phospho-tau-positive inclusions in the cortex and hypothalamus in the brains of ZDF rats and the absence of amyloid-beta deposits. The level of GABAA receptors was lower in the cortex of ZDF rats than SD rats. Proteomic analysis further demonstrated that, compared with SD rats, synaptic-related proteins and pathways were downregulated in the hippocampus of ZDF rats. CONCLUSION These findings provide in vivo evidence for regional reductions in SV2A and GABAA receptor levels in the brains of aged T2DM ZDF rats.
Collapse
Affiliation(s)
- Yanyan Kong
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Lei Cao
- PET Center, Huashan Hospital, Fudan University, Shanghai, China; Inst. Regenerative Medicine, University of Zurich, Zurich, Switzerland
| | - Fang Xie
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiuzhe Wang
- Dept. Neurology, Shanghai Sixth People's Hospital affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chuantao Zuo
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Kuangyu Shi
- Dept. Nuclear Medicine, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Axel Rominger
- Dept. Nuclear Medicine, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Qi Huang
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Jianfei Xiao
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Donglang Jiang
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Yihui Guan
- PET Center, Huashan Hospital, Fudan University, Shanghai, China.
| | - Ruiqing Ni
- Inst. Regenerative Medicine, University of Zurich, Zurich, Switzerland; Dept. Nuclear Medicine, Inselspital, Bern University Hospital, Bern, Switzerland; Inst. Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland.
| |
Collapse
|
6
|
Desmond KL, Lindberg A, Garcia A, Tong J, Harkness MB, Dobrota E, Smart K, Uribe C, Meyer JH, Houle S, Strafella AP, Li S, Huang Y, Vasdev N. First-in-Human PET Imaging of [ 18F]SDM-4MP3: A Cautionary Tale. Mol Imaging 2023; 2023:8826977. [PMID: 37719326 PMCID: PMC10504053 DOI: 10.1155/2023/8826977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/06/2023] [Accepted: 07/31/2023] [Indexed: 09/19/2023] Open
Abstract
[18F]SynVesT-1 is a PET radiopharmaceutical that binds to the synaptic vesicle protein 2A (SV2A) and serves as a biomarker of synaptic density with widespread clinical research applications in psychiatry and neurodegeneration. The initial goal of this study was to concurrently conduct PET imaging studies with [18F]SynVesT-1 at our laboratories. However, the data in the first two human PET studies had anomalous biodistribution despite the injected product meeting all specifications during the prerelease quality control protocols. Further investigation, including imaging in rats as well as proton and carbon 2D-NMR spectroscopic studies, led to the discovery that a derivative of the precursor had been received from the manufacturer. Hence, we report our investigation and the first-in-human study of [18F]SDM-4MP3, a structural variant of [18F]SynVesT-1, which does not have the requisite characteristics as a PET radiopharmaceutical for imaging SV2A in the central nervous system.
Collapse
Affiliation(s)
- Kimberly L. Desmond
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Ontario, Canada
| | - Anton Lindberg
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Armando Garcia
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Junchao Tong
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Michael B. Harkness
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Elena Dobrota
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Kelly Smart
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Ontario, Canada
| | - Carme Uribe
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Jeffrey H. Meyer
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Ontario, Canada
| | - Sylvain Houle
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Ontario, Canada
| | - Antonio P. Strafella
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Krembil Brain Institute, University Health Network, University of Toronto, Ontario, Canada
| | - Songye Li
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA
| | - Yiyun Huang
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA
| | - Neil Vasdev
- Azrieli Centre for Neuro-Radiochemistry & Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Ontario, Canada
| |
Collapse
|
7
|
Xiong M, Roshanbin S, Sehlin D, Hansen HD, Knudsen GM, Rokka J, Eriksson J, Syvänen S. Synaptic density in aging mice measured by [ 18F]SynVesT-1 PET. Neuroimage 2023:120230. [PMID: 37355199 DOI: 10.1016/j.neuroimage.2023.120230] [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: 12/03/2022] [Revised: 05/03/2023] [Accepted: 06/14/2023] [Indexed: 06/26/2023] Open
Abstract
Synaptic alterations in certain brain structures are related to cognitive decline in neurodegeneration and in aging. Synaptic loss in many neurodegenerative diseases can be visualized by positron emission tomography (PET) imaging of synaptic vesicle glycoprotein 2A (SV2A). However, the use of SV2A PET for studying synaptic changes during aging is not particularly explored. Thus, in the present study, PET ligand [18F]SynVesT-1, which binds to SV2A, was used to investigate synaptic density at different ages in healthy mice. Wild type C57BL/6 mice divided into three age groups (4-5 months (n = 7), 12-14 months (n = 11), 17-19 months (n = 7)) were PET scanned with [18F]SynVesT-1. Brain retention of [18F]SynVesT-1 expressed as the volume of distribution (VIDIF) was calculated using an image-derived input function. Estimates of VIDIF were derived using either a one-tissue compartment model (1TCM), a two-tissue compartment model (2TCM), or the Logan plot with blood input to find the best-fit model for [18F]SynVesT-1. After the PET scans, tissue sections were immunostained for the detection of SV2A and neuronal markers. We found that [18F]SynVesT-1 data acquired 60 min post intravenously injection and analyzed with 1TCM described the brain pharmacokinetics of the radioligand in mice well. [18F]SynVesT-1 brain retention was lower in the oldest group of mice, indicating a decrease in synaptic density in this age group. However, no gradual age-dependent decrease in synaptic density at a region-specific level was observed. Immunostaining indicated that SV2A expression and neuron numbers were similar across all three age groups. In general, these data obtained in healthy aging mice are consistent with previous findings in humans where synaptic density appeared stable during aging up to a certain age, after which a small decrease is observed.
Collapse
Affiliation(s)
- Mengfei Xiong
- Molecular Geriatrics, Department of Public Health and Caring Sciences, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Sahar Roshanbin
- Molecular Geriatrics, Department of Public Health and Caring Sciences, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Dag Sehlin
- Molecular Geriatrics, Department of Public Health and Caring Sciences, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Hanne D Hansen
- Neurobiology Research Unit, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Johanna Rokka
- Molecular Geriatrics, Department of Public Health and Caring Sciences, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Jonas Eriksson
- PET Centre, Uppsala University Hospital, SE-751 85 Uppsala, Sweden; Department of Medicinal Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Stina Syvänen
- Molecular Geriatrics, Department of Public Health and Caring Sciences, Uppsala University, SE-751 85 Uppsala, Sweden.
| |
Collapse
|
8
|
Yang Y, Zheng C, Chen B, Hernandez NC, Faust PL, Cai Z, Louis ED, Matuskey D. Decreased Synaptic Vesicle Glycoprotein 2A Binding in the Human Postmortem Essential Tremor Cerebellum: Evidence of Reduction in Synaptic Density. RESEARCH SQUARE 2023:rs.3.rs-2838184. [PMID: 37205584 PMCID: PMC10187382 DOI: 10.21203/rs.3.rs-2838184/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Objective Despite being one of the most prevalent neurological diseases, the pathophysiology of essential tremor (ET) is not fully understood. Neuropathological studies have identified numerous degenerative changes in the cerebellum of ET patients, however. These data align with considerable clinical and neurophysiological data linking ET to the cerebellum. While neuroimaging studies have variably shown mild atrophy in the cerebellum, marked atrophy is not a clear feature of the cerebellum in ET and that a search for a more suitable neuroimaging signature of neurodegeneration is in order. Postmortem studies in ET have examined different neuropathological alterations in the cerebellum, but as of yet have not focused on measures of generalized synaptic markers. This pilot study focuses on synaptic vesicle glycoprotein 2A (SV2A), a protein expressed in practically all synapses in the brain, as a measure of synaptic density in postmortem ET cases. Methods The current study utilized autoradiography with the SV2A radioligand [ 18 F]SDM-16 to assess synaptic density in the cerebellar cortex and dentate nucleus in three ET cases and three age-matched controls. Results Using [ 18 F]SDM-16, SV2A was 53% and 46% lower in the cerebellar cortex and dentate nucleus, respectively, in ET cases compared to age-matched controls. Conclusion For the first time, using in vitro SV2A autoradiography, we have observed significantly lower synaptic density in the cerebellar cortex and dentate nucleus of ET cases. Future research could focus on in vivo imaging in ET to explore whether SV2A imaging could serve as a much-needed disease biomarker.
Collapse
Affiliation(s)
| | | | | | | | - Phyllis L Faust
- Columbia University Vagelos College of Physicians and Surgeons and the New York Presbyterian Hospital
| | | | - Elan D Louis
- University of Texas Southwestern School of Medicine
| | | |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
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.
Collapse
Affiliation(s)
- Samo Ribarič
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
McErlain H, McLean EB, Morgan TEF, Burianova VK, Tavares AAS, Sutherland A. Organocatalytic Asymmetric Synthesis of SynVesT-1, a Synaptic Density Positron Emission Tomography Imaging Agent. J Org Chem 2022; 87:14443-14451. [PMID: 36222243 PMCID: PMC9639009 DOI: 10.1021/acs.joc.2c01895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heterocyclic nonacetamide ligands are used as positron emission tomography (PET) imaging agents of the synaptic vesicle glycoprotein 2A (SV2A), with potential applications in the diagnosis of various neuropsychiatric diseases. To date, the main synthetic strategy to access these optically active compounds has involved the racemic synthesis of a late-stage intermediate followed by the separation of the enantiomers. Here, we describe the use of iminium organocatalysis for the asymmetric synthesis of SynVesT-1, an important PET imaging agent of SV2A. The key step involved the conjugate addition of nitromethane with a cinnamaldehyde in the presence of the Jørgensen-Hayashi catalyst using the Merck dual acid cocatalyst system. Pinnick-type oxidation and esterification of the adduct was then followed by chemoselective nitro group reduction and cyclization using nickel borate. N-Alkylation of the resulting lactam then completed the seven-step synthesis of SynVesT-1. This approach was amenable for the synthesis of an organotin analogue, which following copper(II)-mediated fluoro-destannylation allowed rapid access to [18F]SynVesT-1.
Collapse
Affiliation(s)
- Holly McErlain
- School
of Chemistry, The Joseph Black Building, University of Glasgow, GlasgowG12 8QQ, U.K.
| | - Euan B. McLean
- School
of Chemistry, The Joseph Black Building, University of Glasgow, GlasgowG12 8QQ, U.K.
| | - Timaeus E. F. Morgan
- BHF-University
Centre for Cardiovascular Science, University
of Edinburgh, EdinburghEH16 4TJ, U.K.
| | - Valeria K. Burianova
- School
of Chemistry, The Joseph Black Building, University of Glasgow, GlasgowG12 8QQ, U.K.
| | - Adriana A. S. Tavares
- BHF-University
Centre for Cardiovascular Science, University
of Edinburgh, EdinburghEH16 4TJ, U.K.
| | - Andrew Sutherland
- School
of Chemistry, The Joseph Black Building, University of Glasgow, GlasgowG12 8QQ, U.K.,
| |
Collapse
|
13
|
Chen B, Marquez-Nostra B, Belitzky E, Toyonaga T, Tong J, Huang Y, Cai Z. PET Imaging in Animal Models of Alzheimer’s Disease. Front Neurosci 2022; 16:872509. [PMID: 35685772 PMCID: PMC9171374 DOI: 10.3389/fnins.2022.872509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
The successful development and translation of PET imaging agents targeting β-amyloid plaques and hyperphosphorylated tau tangles have allowed for in vivo detection of these hallmarks of Alzheimer’s disease (AD) antemortem. Amyloid and tau PET have been incorporated into the A/T/N scheme for AD characterization and have become an integral part of ongoing clinical trials to screen patients for enrollment, prove drug action mechanisms, and monitor therapeutic effects. Meanwhile, preclinical PET imaging in animal models of AD can provide supportive information for mechanistic studies. With the recent advancement of gene editing technologies and AD animal model development, preclinical PET imaging in AD models will further facilitate our understanding of AD pathogenesis/progression and the development of novel treatments. In this study, we review the current state-of-the-art in preclinical PET imaging using animal models of AD and suggest future research directions.
Collapse
|
14
|
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: 18] [Impact Index Per Article: 9.0] [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.
Collapse
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
| |
Collapse
|
15
|
Zhu Z, Lu J, Wang S, Peng W, Yang Y, Chen C, Zhou X, Yang X, Xin W, Chen X, Pi J, Yin W, Yao L, Pi R. Acrolein, an endogenous aldehyde induces synaptic dysfunction in vitro and in vivo: Involvement of RhoA/ROCK2 pathway. Aging Cell 2022; 21:e13587. [PMID: 35315217 PMCID: PMC9009232 DOI: 10.1111/acel.13587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/19/2022] [Accepted: 02/25/2022] [Indexed: 11/29/2022] Open
Abstract
Acrolein, an unsaturated aldehyde, is increased in the brain of Alzheimer's disease (AD) patients and identified as a potential inducer of sporadic AD. Synaptic dysfunction, as a typical pathological change occurring in the early stage of AD, is most closely associated with the severity of dementia. However, there remains a lack of clarity on the mechanisms of acrolein inducing AD-like pathology and synaptic impairment. In this study, acrolein-treated primary cultured neurons and mice were applied to investigate the effects of acrolein on cognitive impairment and synaptic dysfunction and their signaling mechanisms. In vitro, ROCK inhibitors, Fasudil, and Y27632, could attenuate the axon ruptures and synaptic impairment caused by acrolein. Meanwhile, RNA-seq distinct differentially expressed genes in acrolein models and initially linked activated RhoA/Rho-kinase2 (ROCK2) to acrolein-induced synaptic dysfunction, which could regulate neuronal cytoskeleton and neurite. The Morris water maze test and in vivo field excitatory postsynaptic potential (fEPSP) were performed to evaluate spatial memory and long-term potential (LTP), respectively. Acrolein induced cognitive impairment and attenuated LTP. Furthermore, the protein level of Synapsin 1 and postsynaptic density 95 (PSD95) and dendritic spines density were also decreased in acrolein-exposed mice. These changes were improved by ROCK2 inhibitor Fasudil or in ROCK2+/- mice. Together, our findings suggest that RhoA/ROCK2 signaling pathway plays a critical role in acrolein-induced synaptic damage and cognitive dysfunction, suggesting inhibition of ROCK2 should benefit to the early AD.
Collapse
Affiliation(s)
- Zeyu Zhu
- School of Medicine Sun Yat‐Sen University Guangzhou China
- School of Pharmaceutical Sciences Sun Yat‐Sen University Guangzhou China
| | - Junfeng Lu
- School of Pharmaceutical Sciences Sun Yat‐Sen University Guangzhou China
- Department of Internal Medicine The Affiliated Tumor Hospital of Zhengzhou University Zhengzhou China
| | - Shuyi Wang
- School of Medicine Sun Yat‐Sen University Guangzhou China
| | - Weijia Peng
- School of Pharmaceutical Sciences Sun Yat‐Sen University Guangzhou China
| | - Yang Yang
- School of Medicine Sun Yat‐Sen University Guangzhou China
| | - Chen Chen
- School of Pharmaceutical Sciences Sun Yat‐Sen University Guangzhou China
| | - Xin Zhou
- Zhongshan School of Medicine Sun Yat‐Sen University Guangzhou China
| | - Xifei Yang
- Key Laboratory of Modern Toxicology of Shenzhen Center for Disease Control and Prevention
| | - Wenjun Xin
- Zhongshan School of Medicine Sun Yat‐Sen University Guangzhou China
| | - Xinyi Chen
- School of Pharmaceutical Sciences South China Research Center for Acupuncture and Moxibustion Guangzhou University of Chinese Medicine Guangzhou China
| | - Jiakai Pi
- Guangzhou Foreign Language School Guangzhou China
| | - Wei Yin
- Zhongshan School of Medicine Sun Yat‐Sen University Guangzhou China
| | - Lin Yao
- Research Institute of Acupuncture and Moxibustion Shandong University of Traditional Chinese Medicine Jinan China
| | - Rongbiao Pi
- School of Medicine Sun Yat‐Sen University Guangzhou China
- International Joint Laboratory<SYSU‐PolyU HK> of Novel Anti‐Dementia Drugs of Guangzhou Guangzhou China
- Guangdong Province Key Laboratory of Brain Function and Disease Sun Yat‐sen University Guangzhou China
| |
Collapse
|
16
|
Toyonaga T, Fesharaki-Zadeh A, Strittmatter SM, Carson RE, Cai Z. PET Imaging of Synaptic Density: Challenges and Opportunities of Synaptic Vesicle Glycoprotein 2A PET in Small Animal Imaging. Front Neurosci 2022; 16:787404. [PMID: 35345546 PMCID: PMC8957200 DOI: 10.3389/fnins.2022.787404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/14/2022] [Indexed: 12/02/2022] Open
Abstract
The development of novel PET imaging agents for synaptic vesicle glycoprotein 2A (SV2A) allowed for the in vivo detection of synaptic density changes, which are correlated with the progression and severity of a variety of neuropsychiatric diseases. While multiple ongoing clinical investigations using SV2A PET are expanding its applications rapidly, preclinical SV2A PET imaging in animal models is an integral component of the translation research and provides supporting and complementary information. Herein, we overview preclinical SV2A PET studies in animal models of neurodegenerative disorders and discuss the opportunities and practical challenges in small animal SV2A PET imaging. At the Yale PET Center, we have conducted SV2A PET imaging studies in animal models of multiple diseases and longitudinal SV2A PET allowed us to evaluate synaptic density dynamics in the brains of disease animal models and to assess pharmacological effects of novel interventions. In this article, we discuss key considerations when designing preclinical SV2A PET imaging studies and strategies for data analysis. Specifically, we compare the brain imaging characteristics of available SV2A tracers, i.e., [11C]UCB-J, [18F]SynVesT-1, [18F]SynVesT-2, and [18F]SDM-16, in rodent brains. We also discuss the limited spatial resolution of PET scanners for small brains and challenges of kinetic modeling. We then compare different injection routes and estimate the maximum throughput (i.e., number of animals) per radiotracer synthesis by taking into account the injectable volume for each injection method, injected mass, and radioactivity half-lives. In summary, this article provides a perspective for designing and analyzing SV2A PET imaging studies in small animals.
Collapse
Affiliation(s)
- Takuya Toyonaga
- Positron Emission Tomography (PET) Center, Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States,*Correspondence: Takuya Toyonaga,
| | - Arman Fesharaki-Zadeh
- Psychiatry, Yale School of Medicine, New Haven, CT, United States,Neurology, Yale School of Medicine, New Haven, CT, United States
| | - Stephen M. Strittmatter
- Neurology, Yale School of Medicine, New Haven, CT, United States,Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Richard E. Carson
- Positron Emission Tomography (PET) Center, Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States
| | - Zhengxin Cai
- Positron Emission Tomography (PET) Center, Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States,Zhengxin Cai,
| |
Collapse
|