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Emvalomenos GM, Kang JWM, Jupp B, Mychasiuk R, Keay KA, Henderson LA. Recent developments and challenges in positron emission tomography imaging of gliosis in chronic neuropathic pain. Pain 2024; 165:2184-2199. [PMID: 38713812 DOI: 10.1097/j.pain.0000000000003247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/05/2024] [Indexed: 05/09/2024]
Abstract
ABSTRACT Understanding the mechanisms that underpin the transition from acute to chronic pain is critical for the development of more effective and targeted treatments. There is growing interest in the contribution of glial cells to this process, with cross-sectional preclinical studies demonstrating specific changes in these cell types capturing targeted timepoints from the acute phase and the chronic phase. In vivo longitudinal assessment of the development and evolution of these changes in experimental animals and humans has presented a significant challenge. Recent technological advances in preclinical and clinical positron emission tomography, including the development of specific radiotracers for gliosis, offer great promise for the field. These advances now permit tracking of glial changes over time and provide the ability to relate these changes to pain-relevant symptomology, comorbid psychiatric conditions, and treatment outcomes at both a group and an individual level. In this article, we summarize evidence for gliosis in the transition from acute to chronic pain and provide an overview of the specific radiotracers available to measure this process, highlighting their potential, particularly when combined with ex vivo / in vitro techniques, to understand the pathophysiology of chronic neuropathic pain. These complementary investigations can be used to bridge the existing gap in the field concerning the contribution of gliosis to neuropathic pain and identify potential targets for interventions.
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Affiliation(s)
- Gaelle M Emvalomenos
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - James W M Kang
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Bianca Jupp
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Kevin A Keay
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Luke A Henderson
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
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Chauveau F, Winkeler A, Chalon S, Boutin H, Becker G. PET imaging of neuroinflammation: any credible alternatives to TSPO yet? Mol Psychiatry 2024:10.1038/s41380-024-02656-9. [PMID: 38997465 DOI: 10.1038/s41380-024-02656-9] [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: 12/19/2023] [Revised: 06/26/2024] [Accepted: 07/01/2024] [Indexed: 07/14/2024]
Abstract
Over the last decades, the role of neuroinflammation in neuropsychiatric conditions has attracted an exponentially growing interest. A key driver for this trend was the ability to image brain inflammation in vivo using PET radioligands targeting the Translocator Protein 18 kDa (TSPO), which is known to be expressed in activated microglia and astrocytes upon inflammatory events as well as constitutively in endothelial cells. TSPO is a mitochondrial protein that is expressed mostly by microglial cells upon activation but is also expressed by astrocytes in some conditions and constitutively by endothelial cells. Therefore, our current understanding of neuroinflammation dynamics is hampered by the lack of alternative targets available for PET imaging. We performed a systematic search and review on radiotracers developed for neuroinflammation PET imaging apart from TSPO. The following targets of interest were identified through literature screening (including previous narrative reviews): P2Y12R, P2X7R, CSF1R, COX (microglial targets), MAO-B, I2BS (astrocytic targets), CB2R & S1PRs (not specific of a single cell type). We determined the level of development and provided a scoping review for each target. Strikingly, astrocytic biomarker MAO-B has progressed in clinical investigations the furthest, while few radiotracers (notably targeting S1P1Rs, CSF1R) are being implemented in clinical investigations. Other targets such as CB2R and P2X7R have proven disappointing in clinical studies (e.g. poor signal, lack of changes in disease conditions, etc.). While astrocytic targets are promising, development of new biomarkers and tracers specific for microglial activation has proven challenging.
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Affiliation(s)
- Fabien Chauveau
- Université Claude Bernard Lyon 1, Centre de Recherche en Neurosciences de Lyon, Inserm U1028, CNRS UMR5292, BIORAN, Groupement Hospitalier Est - CERMEP, 59 boulevard Pinel, 69677, Bron, Cedex, France
| | - Alexandra Winkeler
- Université Paris-Saclay, Inserm, CNRS, CEA, BioMaps, Service Hospitalier Frédéric Joliot, 4 place du général Leclerc, 91401, Orsay, France
| | - Sylvie Chalon
- UMR 1253 iBrain, Université de Tours - INSERM, Bâtiment Planiol, UFR de Médecine, 10 Boulevard Tonnellé, 37032, Tours, Cedex 01, France
| | - Hervé Boutin
- UMR 1253 iBrain, Université de Tours - INSERM, Bâtiment Planiol, UFR de Médecine, 10 Boulevard Tonnellé, 37032, Tours, Cedex 01, France.
| | - Guillaume Becker
- Université Claude Bernard Lyon 1, Centre de Recherche en Neurosciences de Lyon, Inserm U1028, CNRS UMR5292, BIORAN, Groupement Hospitalier Est - CERMEP, 59 boulevard Pinel, 69677, Bron, Cedex, France
- Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail, 14 rue Pierre et Marie Curie, 94701, Maisons-Alfort, Cedex, France
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Lee N, Choi JY, Ryu YH. The development status of PET radiotracers for evaluating neuroinflammation. Nucl Med Mol Imaging 2024; 58:160-176. [PMID: 38932754 PMCID: PMC11196502 DOI: 10.1007/s13139-023-00831-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 06/28/2024] Open
Abstract
Neuroinflammation is associated with the pathophysiologies of neurodegenerative and psychiatric disorders. Evaluating neuroinflammation using positron emission tomography (PET) plays an important role in the early diagnosis and determination of proper treatment of brain diseases. To quantify neuroinflammatory responses in vivo, many PET tracers have been developed using translocator proteins, imidazole-2 binding site, cyclooxygenase, monoamine oxidase-B, adenosine, cannabinoid, purinergic P2X7, and CSF-1 receptors as biomarkers. In this review, we introduce the latest developments in PET tracers that can image neuroinflammation, focusing on clinical trials, and further consider their current implications.
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Affiliation(s)
- Namhun Lee
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
| | - Jae Yong Choi
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
- Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul, Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Ishii H, Minegishi K, Nagatsu K, Nengaki N, Zhang MR. Novel synthesis of 11C-labeled imidazolines via Pd(0)-mediated 11C-carbomethoxylation using [ 11C]CO and arylborons. J Labelled Comp Radiopharm 2024; 67:227-234. [PMID: 37957035 DOI: 10.1002/jlcr.4072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/07/2023] [Accepted: 10/16/2023] [Indexed: 11/15/2023]
Abstract
A labeling technique was developed for the imidazoline I2 receptor ligand 2-(3-fluoro-tolyl)-4, 5-dihydro-1H-imidazole (FTIMD) using Pd(0)-mediated 11C-carbomethoxylation with [11C]CO, followed by imidazoline ring formation with ethylenediamine-trimethylaluminium (EDA-AlMe3). To achieve this, [11C]CO was passed through a methanol (MeOH) solution containing 3-fluoro-4-methylphenylboronic acid (1), palladium (II) acetate (Pd [OAc]2), triphenylphosphine (PPh3), and p-benzoquinone (PBQ). The mixture was then heated at 65°C for 5 min. EDA was introduced into the reaction mixture, and MeOH was completely evaporated at temperatures exceeding 100°C. The dried reaction mixture was combined with an EDA-AlMe (1:1) toluene solution and heated at 145°C for 10 min. Portions of the reaction mixture were analyzed through high-performance liquid chromatography, resulting in [11C]FTIMD with 26% (n = 2) decay-corrected radiochemical yield (RCY). This method could be utilized for various arylborons to produce [2-11C]imidazolines 4a-h with RCYs ranging from low to moderate. Notably, [2-11C]benazoline was obtained with a moderate RCY of 65%. The proposed technique serves as an alternative to the Grignard method, which uses [11C]CO to generate a [2-11C]-labeled imidazoline ring.
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Affiliation(s)
- Hideki Ishii
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Katsuyuki Minegishi
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Kotaro Nagatsu
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- SHI Accelerator Service Ltd., Tokyo, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
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Parker CA, Nutt DJ, Tyacke RJ. Imidazoline-I2 PET Tracers in Neuroimaging. Int J Mol Sci 2023; 24:9787. [PMID: 37372936 DOI: 10.3390/ijms24129787] [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: 04/14/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
Targeting neuroinflammation, and in particular, microglial activation and astrocytosis, is a current area of the focus of new treatment interventions for a number of neurodegenerative disorders. Probing the roles of microglia and astrocytes in human disease requires the development of useful tools, such as PET imaging tools that are specific for the cell type(s) of interest. This review concentrates on the recent advances in the development of Imidazoline2 binding site (I2BS) PET tracers, which are purported to target astrocytes, and hence could represent key clinical imaging tools for targeting astrocytes in neurodegenerative disease. Five PET tracers for the I2BS are described in this review, with only one (11C-BU99008) being currently validated to GMP for clinical use, and data reported from healthy volunteers, Alzheimer's disease patients, and Parkinson's disease patients. The clinical data utilising 11C-BU99008 have revealed the potential early involvement of astrogliosis in neurodegeneration that might precede the activation of microglia, which, if confirmed, could provide a vital new means for potentially targeting neurodegeneration earlier in the disease course.
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Affiliation(s)
- Christine A Parker
- Neuropsychopharmacology Unit, Division of Psychiatry, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
- GlaxoSmithKline, Gunnels Wood Road, Stevenage SG1 2NY, UK
| | - David J Nutt
- Neuropsychopharmacology Unit, Division of Psychiatry, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Robin J Tyacke
- Neuropsychopharmacology Unit, Division of Psychiatry, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
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Brumberg J, Varrone A. New PET radiopharmaceuticals for imaging CNS diseases. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00002-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Zeng Z, Roussakis AA, Lao-Kaim NP, Piccini P. Astrocytes in Parkinson's disease: from preclinical assays to in vivo imaging and therapeutic probes. Neurobiol Aging 2020; 95:264-270. [PMID: 32905922 DOI: 10.1016/j.neurobiolaging.2020.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/30/2020] [Accepted: 07/14/2020] [Indexed: 12/11/2022]
Abstract
Parkinson's disease (PD) is increasingly thought to be associated with glial pathology. Recently, research in neurodegenerative disorders has applied a greater focus to better understanding the role of astrocytes in the disease pathophysiology. In this article, we review results from the latest preclinical and clinical work, including functional imaging studies on astrocytes in PD and highlight key molecules that may prove valuable as biomarkers. We discuss how astrocytes may contribute to the initiation and progression of PD. We additionally present trials of investigational medicinal products and the current background for the design of future clinical trials.
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Affiliation(s)
- Zhou Zeng
- Department of Brain Sciences, Imperial College London, Neurology Imaging Unit, London, UK; Department of Neurology, Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | | | - Nicholas P Lao-Kaim
- Department of Brain Sciences, Imperial College London, Neurology Imaging Unit, London, UK
| | - Paola Piccini
- Department of Brain Sciences, Imperial College London, Neurology Imaging Unit, London, UK.
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Tyacke RJ, Myers JFM, Venkataraman A, Mick I, Turton S, Passchier J, Husbands SM, Rabiner EA, Gunn RN, Murphy PS, Parker CA, Nutt DJ. Evaluation of 11C-BU99008, a PET Ligand for the Imidazoline 2 Binding Site in Human Brain. J Nucl Med 2018; 59:1597-1602. [PMID: 29523627 DOI: 10.2967/jnumed.118.208009] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/21/2018] [Indexed: 11/16/2022] Open
Abstract
The imidazoline2 binding site (I2BS) is thought to be expressed in glia and implicated in the regulation of glial fibrillary acidic protein. A PET ligand for this target would be important for the investigation of neurodegenerative and neuroinflammatory diseases. 11C-BU99008 has previously been identified as a putative PET radioligand. Here, we present the first in vivo characterization of this PET radioligand in humans and assess its test-retest reproducibility. Methods: Fourteen healthy male volunteers underwent dynamic PET imaging with 11C-BU99008 and arterial sampling. Six subjects were used in a test-retest assessment, and 8 were used in a pharmacologic evaluation, undergoing a second or third heterologous competition scan with the mixed I2BS/α2-adrenoceptor drug idazoxan (n = 8; 20, 40, 60, and 80 mg) and the mixed irreversible monoamine oxidase type A/B inhibitor isocarboxazid (n = 4; 50 mg). Regional time-activity data were generated from arterial plasma input functions corrected for metabolites using the most appropriate model to derive the outcome measure VT (regional distribution volume). All image processing and kinetic analyses were performed in MIAKAT. Results: Brain uptake of 11C-BU99008 was good, with reversible kinetics and a heterogeneous distribution consistent with known I2BS expression. Model selection criteria indicated that the 2-tissue-compartment model was preferred. VT estimates were high in the striatum (105 ± 21 mL⋅cm-3), medium in the cingulate cortex (62 ± 10 mL⋅cm-3), and low in the cerebellum (41 ± 7 mL⋅cm-3). Test-retest reliability was reasonable. The uptake was dose-dependently reduced throughout the brain by pretreatment with idazoxan, with an average block across all regions of about 60% (VT, ∼30 mL⋅cm-3) at the highest dose (80 mg). The median effective dose for idazoxan was 28 mg. Uptake was not blocked by pretreatment with the monoamine oxidase inhibitor isocarboxazid. Conclusion:11C-BU99008 in human PET studies demonstrates good brain delivery, reversible kinetics, heterogeneous distribution, specific binding signal consistent with I2BS distribution, and good test-retest reliability.
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Affiliation(s)
- Robin J Tyacke
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Jim F M Myers
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Ashwin Venkataraman
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Inge Mick
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Samuel Turton
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Jan Passchier
- Imanova Limited, Imperial College London, London, United Kingdom
| | - Stephen M Husbands
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | | | - Roger N Gunn
- Imanova Limited, Imperial College London, London, United Kingdom
- Restorative Neurosciences, Imperial College London, London, United Kingdom; and
| | - Philip S Murphy
- Experimental Medicine Imaging, GlaxoSmithKline Research and Development Limited, Stevenage, United Kingdom
| | - Christine A Parker
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
- Experimental Medicine Imaging, GlaxoSmithKline Research and Development Limited, Stevenage, United Kingdom
| | - David J Nutt
- Neuropsychopharmacology Unit, Centre for Academic Psychiatry, Division of Brain Sciences, Imperial College London, London, United Kingdom
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Kawamura K, Shimoda Y, Yui J, Zhang Y, Yamasaki T, Wakizaka H, Hatori A, Xie L, Kumata K, Fujinaga M, Ogawa M, Kurihara Y, Nengaki N, Zhang MR. A useful PET probe [ 11C]BU99008 with ultra-high specific radioactivity for small animal PET imaging of I 2-imidazoline receptors in the hypothalamus. Nucl Med Biol 2016; 45:1-7. [PMID: 27835825 DOI: 10.1016/j.nucmedbio.2016.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/14/2016] [Accepted: 10/24/2016] [Indexed: 01/23/2023]
Abstract
INTRODUCTION A positron emission tomography (PET) probe with ultra-high specific radioactivity (SA) enables measuring high receptor specific binding in brain regions by avoiding mass effect of the PET probe itself. It has been reported that PET probe with ultra-high SA can detect small change caused by endogenous or exogenous ligand. Recently, Kealey et al. developed [11C]BU99008, a more potent PET probe for I2-imidazoline receptors (I2Rs) imaging, with a conventional SA (mean 76GBq/μmol) showed higher specific binding in the brain. Here, to detect small change of specific binding for I2Rs caused by endogenous or exogenous ligand in an extremely small region, such as hypothalamus in the brain, we synthesized and evaluated [11C]BU99008 with ultra-high SA as a useful PET probe for small-animal PET imaging of I2Rs. METHODS [11C]BU99008 was prepared by [11C]methylation of N-desmethyl precursor with [11C]methyl iodide. Biodistribution, metabolite analysis, and brain PET studies were conducted in rats. RESULTS [11C]BU99008 with ultra-high SA in the range of 5400-16,600GBq/μmol were successfully synthesized (n=7), and had appropriate radioactivity for in vivo study. In the biodistribution study, the mean radioactivity levels in all investigated tissues except for the kidney did not show significant difference between [11C]BU99008 with ultra-high SA and that with conventional SA. In the metabolite analysis, the percentage of unchanged [11C]BU99008 at 30min after the injection of probes with ultra-high and conventional SA was similar in rat brain and plasma. In the PET study of rats' brain, radioactivity level (AUC30-60 min) in the hypothalamus of rats injected with [11C]BU99008 with ultra-high SA (64 [SUV ∙ min]) was significantly higher than that observed for that with conventional SA (50 [SUV ∙ min]). The specific binding of [11C]BU99008 with ultra-high SA (86% of total binding) for I2R was higher than that of conventional SA (76% of total binding). CONCLUSION A PET study using [11C]BU99008 with ultra-high SA would thus contribute to the detection of small changes in or small regions with I2R expression and hence may be useful in elucidating new functions of I2R.
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Affiliation(s)
- Kazunori Kawamura
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan.
| | - Yoko Shimoda
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Joji Yui
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Yiding Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Hidekatsu Wakizaka
- Department of Medical Physics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Akiko Hatori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Lin Xie
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Masanao Ogawa
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Yusuke Kurihara
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Nobuki Nengaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
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Insight into the Molecular Imaging of Alzheimer's Disease. Int J Biomed Imaging 2016; 2016:7462014. [PMID: 26880871 PMCID: PMC4736963 DOI: 10.1155/2016/7462014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/16/2015] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease is a complex neurodegenerative disease affecting millions of individuals worldwide. Earlier it was diagnosed only via clinical assessments and confirmed by postmortem brain histopathology. The development of validated biomarkers for Alzheimer's disease has given impetus to improve diagnostics and accelerate the development of new therapies. Functional imaging like positron emission tomography (PET), single photon emission computed tomography (SPECT), functional magnetic resonance imaging (fMRI), and proton magnetic resonance spectroscopy provides a means of detecting and characterising the regional changes in brain blood flow, metabolism, and receptor binding sites that are associated with Alzheimer's disease. Multimodal neuroimaging techniques have indicated changes in brain structure and metabolic activity, and an array of neurochemical variations that are associated with neurodegenerative diseases. Radiotracer-based PET and SPECT potentially provide sensitive, accurate methods for the early detection of disease. This paper presents a review of neuroimaging modalities like PET, SPECT, and selected imaging biomarkers/tracers used for the early diagnosis of AD. Neuroimaging with such biomarkers and tracers could achieve a much higher diagnostic accuracy for AD and related disorders in the future.
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Yamasaki T, Fujinaga M, Yui J, Wakizaka H, Ohya T, Nengaki N, Ogawa M, Ikoma Y, Hatori A, Xie L, Kawamura K, Zhang MR. Improved Visualization and Specific Binding for Metabotropic Glutamate Receptor Subtype 1 (mGluR1) Using [11C]ITMM with Ultra-High Specific Activity in Small-Animal PET. PLoS One 2015; 10:e0130006. [PMID: 26076143 PMCID: PMC4468202 DOI: 10.1371/journal.pone.0130006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 04/29/2015] [Indexed: 12/15/2022] Open
Abstract
Metabotropic glutamate receptor subtype 1 (mGluR1) is a crucial target in the development of new medications to treat central nervous system (CNS) disorders. Recently, we developed N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-[11C]methoxy-N-methyl-benzamide ([11C]ITMM) as a useful positron emission tomography (PET) probe for mGluR1 in clinical studies. Here, we aimed to improve visualization and threshold of specific binding for mGluR1 using [11C]ITMM with ultra-high specific activity (SA) of > 3,500 GBq/μmol in rat brains. A two-tissue compartment model indicated large differences between the two SAs in the constants k3 and k4, representing binding ability for mGluR1, while constants K1 and k2 showed no differences. The total distribution volume (VT) values of conventional and ultra-high SA were 9.1 and 11.2 in the thalamus, 7.7 and 9.7 in the striatum, and 6.4 and 8.5 mL/cm3 in the substantia nigra, respectively. The specific binding of [11C]ITMM with ultra-high SA was significantly higher than the conventional SA, especially in the basal ganglia. Parametric PET images scaled with VT of the ultra-high SA clearly identified regional differences in the rat brain. In conclusion, PET studies using [11C]ITMM with ultra-high SA could sufficiently improve visualization and specific binding for mGluR1, which could help further understanding for mGluR1 functions in CNS disorders.
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Affiliation(s)
- Tomoteru Yamasaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- * E-mail:
| | - Masayuki Fujinaga
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Joji Yui
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hidekatsu Wakizaka
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tomoyuki Ohya
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Nobuki Nengaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Masanao Ogawa
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yoko Ikoma
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Akiko Hatori
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Lin Xie
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazunori Kawamura
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Ming-Rong Zhang
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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In vivo evaluation of a new 18F-labeled PET ligand, [18F]FEBU, for the imaging of I2-imidazoline receptors. Nucl Med Biol 2015; 42:406-12. [DOI: 10.1016/j.nucmedbio.2014.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 12/01/2014] [Accepted: 12/19/2014] [Indexed: 11/20/2022]
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Suzuki M, Doi H, Koyama H, Zhang Z, Hosoya T, Onoe H, Watanabe Y. Pd0-Mediated Rapid Cross-Coupling Reactions, the RapidC-[11C]Methylations, Revolutionarily Advancing the Syntheses of Short-Lived PET Molecular Probes. CHEM REC 2014; 14:516-41. [DOI: 10.1002/tcr.201400002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Indexed: 11/12/2022]
Affiliation(s)
- Masaaki Suzuki
- National Center for Geriatrics and Gerontology; 35 Gengo Morioka-cho Obu-shi Aichi 474-8511 Japan
| | - Hisashi Doi
- Division of Bio-Function Dynamics Imaging; Riken Center for Life Science Technologies (CLST); 6-7-3 Minatojima-minamimachi Chuo-ku Kobe 650-0047 Japan
| | - Hiroko Koyama
- Division of Regeneration and Advanced Medical Science; Graduate School of Medicine; Gifu University; 1-1 Yanagido Gifu 501-1194 Japan
| | - Zhouen Zhang
- Division of Bio-Function Dynamics Imaging; Riken Center for Life Science Technologies (CLST); 6-7-3 Minatojima-minamimachi Chuo-ku Kobe 650-0047 Japan
| | - Takamitsu Hosoya
- Division of Regeneration and Advanced Medical Science; Graduate School of Medicine; Gifu University; 1-1 Yanagido Gifu 501-1194 Japan
| | - Hirotaka Onoe
- Division of Bio-Function Dynamics Imaging; Riken Center for Life Science Technologies (CLST); 6-7-3 Minatojima-minamimachi Chuo-ku Kobe 650-0047 Japan
| | - Yasuyoshi Watanabe
- Division of Bio-Function Dynamics Imaging; Riken Center for Life Science Technologies (CLST); 6-7-3 Minatojima-minamimachi Chuo-ku Kobe 650-0047 Japan
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Yamasaki T, Kumata K, Yui J, Fujinaga M, Furutsuka K, Hatori A, Xie L, Ogawa M, Nengaki N, Kawamura K, Zhang MR. Synthesis and evaluation of [11C]MMPIP as a potential radioligand for imaging of metabotropic glutamate 7 receptor in the brain. EJNMMI Res 2013; 3:54. [PMID: 23870677 PMCID: PMC3751550 DOI: 10.1186/2191-219x-3-54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/11/2013] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Metabotropic glutamate 7 (mGlu7) receptor is a crucial target protein for the development of pharmaceuticals against central nervous system disorders. In the present study, we synthesized [11C]MMPIP, a putative radioligand for mGlu7 (binding constant KB = 30 nM), and evaluated its potential for imaging of mGlu7 via in vitro and in vivo techniques. METHODS [11C]MMPIP was synthesized by the reaction of phenol precursor 3 with [11C]CH3I. In vitro autoradiography using [11C]MMPIP was performed on rat brain sections. To determine in vitro specific binding of [11C]MMPIP with mGlu7, a blocking study was conducted by co-incubation with excess AMN082, a selective antagonist for mGlu7, or unlabeled MMPIP. Positron emission tomography (PET) studies and ex vivo metabolite analysis were carried out on rat brains. RESULTS [11C]MMPIP was obtained with two specific activity (SA) levels of average 58 (conventional) and 3,800 (high SA) GBq/μmol, respectively. High radioactive signals derived from conventional [11C]MMPIP in the in vitro autoradiography were seen in the thalamus, medulla oblongata, and striatum, corresponding with comprehensive brain distributions of mGlu7. Co-incubation with ANM082 or unlabeled MMPIP reduced the radioactive signals in the brain sections, respectively. In the PET studies with [11C]MMPIP, no specific uptake relative to mGlu7 was found in the examined brain regions. CONCLUSION Despite in vitro specific binding of [11C]MMPIP with mGlu7, visualization of mGlu7 in the living brain using PET was not successful. Development of new ligand candidates with higher affinity for mGlu7 is necessary.
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Affiliation(s)
- Tomoteru Yamasaki
- Molecular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
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Benadiba M, Luurtsema G, Wichert-Ana L, Buchpigel CA, Filho GB. New Molecular Targets for PET and SPECT Imaging in Neurodegenerative Diseases. BRAZILIAN JOURNAL OF PSYCHIATRY 2012; 34 Suppl 2:S125-36. [DOI: 10.1016/j.rbp.2012.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 02/29/2012] [Indexed: 01/23/2023]
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