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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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2
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Malpetti M, Franzmeier N, Brendel M. PET Imaging to Measure Neuroinflammation In Vivo. Methods Mol Biol 2024; 2785:177-193. [PMID: 38427195 DOI: 10.1007/978-1-0716-3774-6_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
This paper provides an overview of the role of neuroinflammation in Alzheimer's disease and other neurodegenerative diseases, highlighting the potential of anti-inflammatory treatments to slow or prevent decline. This research focuses on the use of positron emission tomography (PET) imaging to visualize and quantify molecular brain changes in patients, specifically microglial activation and reactive astrogliosis. We discuss the development and application of several PET radioligands, including first-generation ligands like PK11195 and Ro5-4864, as well as second- and third-generation ligands such as [11C]PBR28, [18F]DPA-714, [18F]GE-180, and [11C]ER176. These ligands target the 18-kDa translocator protein (TSPO), which is overexpressed in activated microglia and upregulated in astrocytes. We also address the limitations of these ligands, such as low brain uptake, poor penetration of the blood-brain barrier, short half-life, and variable kinetic behavior. Furthermore, we demonstrate the impact of genetic polymorphisms on ligand binding.
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Affiliation(s)
- Maura Malpetti
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Nicolai Franzmeier
- Institute for Stroke and Dementia Research, LMU University Hospital, LMU Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal and Gothenburg, Sweden
| | - Matthias Brendel
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Munich, Germany.
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
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3
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Cools R, Kerkhofs K, Leitao RCF, Bormans G. Preclinical Evaluation of Novel PET Probes for Dementia. Semin Nucl Med 2023; 53:599-629. [PMID: 37149435 DOI: 10.1053/j.semnuclmed.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/08/2023]
Abstract
The development of novel PET imaging agents that selectively bind specific dementia-related targets can contribute significantly to accurate, differential and early diagnosis of dementia causing diseases and support the development of therapeutic agents. Consequently, in recent years there has been a growing body of literature describing the development and evaluation of potential new promising PET tracers for dementia. This review article provides a comprehensive overview of novel dementia PET probes under development, classified by their target, and pinpoints their preclinical evaluation pathway, typically involving in silico, in vitro and ex/in vivo evaluation. Specific target-associated challenges and pitfalls, requiring extensive and well-designed preclinical experimental evaluation assays to enable successful clinical translation and avoid shortcomings observed for previously developed 'well-established' dementia PET tracers are highlighted in this review.
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Affiliation(s)
- Romy Cools
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Kobe Kerkhofs
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; NURA, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Renan C F Leitao
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
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4
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Raval NR, Wetherill RR, Wiers CE, Dubroff JG, Hillmer AT. Positron Emission Tomography of Neuroimmune Responses in Humans: Insights and Intricacies. Semin Nucl Med 2023; 53:213-229. [PMID: 36270830 PMCID: PMC11261531 DOI: 10.1053/j.semnuclmed.2022.08.008] [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: 08/15/2022] [Accepted: 08/30/2022] [Indexed: 11/06/2022]
Abstract
The brain's immune system plays a critical role in responding to immune challenges and maintaining homeostasis. However, dysregulated neuroimmune function contributes to neurodegenerative disease and neuropsychiatric conditions. In vivo positron emission tomography (PET) imaging of the neuroimmune system has facilitated a greater understanding of its physiology and the pathology of some neuropsychiatric conditions. This review presents an in-depth look at PET findings from human neuroimmune function studies, highlighting their importance in current neuropsychiatric research. Although the majority of human PET studies feature radiotracers targeting the translocator protein 18 kDa (TSPO), this review also considers studies with other neuroimmune targets, including monoamine oxidase B, cyclooxygenase-1 and cyclooxygenase-2, nitric oxide synthase, and the purinergic P2X7 receptor. Promising new targets, such as colony-stimulating factor 1, Sphingosine-1-phosphate receptor 1, and the purinergic P2Y12 receptor, are also discussed. The significance of validating neuroimmune targets and understanding their function and expression is emphasized in this review to better identify and interpret PET results.
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Affiliation(s)
- Nakul R Raval
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT
| | - Reagan R Wetherill
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Corinde E Wiers
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jacob G Dubroff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ansel T Hillmer
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT; Department of Psychiatry, Yale University, New Haven, CT.
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5
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Kim J, Kim YK. Molecular Imaging of Neuroinflammation in Alzheimer's Disease and Mild Cognitive Impairment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1411:301-326. [PMID: 36949316 DOI: 10.1007/978-981-19-7376-5_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent neurocognitive disorder. Due to the ineffectiveness of treatments targeting the amyloid cascade, molecular biomarkers for neuroinflammation are attracting attention with increasing knowledge about the role of neuroinflammation in the pathogenesis of AD. This chapter will explore the results of studies using molecular imaging for diagnosing AD and mild cognitive impairment (MCI). Because it is critical to interpreting the data to understand which substances are targeted in molecular imaging, this chapter will discuss the two most significant targets, microglia and astrocytes, as well as the best-known radioligands for each. Then, neuroimaging results with PET neuroinflammation imaging will be reviewed for AD and MCI. Although a growing body of evidence has suggested that these molecular imaging biomarkers for neuroinflammation may have a role in the diagnosis of AD and MCI, the findings are inconsistent or cross-sectional, which indicates that it is difficult to apply the contents in practice due to the need for additional study. In particular, because the results of multiple interventions targeting neuroinflammation were inconclusive, molecular imaging markers for neuroinflammation can be used in combination with conventional markers to select appropriate patients for early intervention for neuroinflammation rather than as a single marker.
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Affiliation(s)
- Junhyung Kim
- Department of Psychiatry, Korea University College of Medicine, Korea University Guro Hospital, Seoul, Republic of Korea
- Department of Psychiatry, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Yong-Ku Kim
- Department of Psychiatry, Korea University Ansan Hospital, Ansan, Republic of Korea.
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Stopschinski BE, Weideman RA, McMahan D, Jacob DA, Little BB, Chiang HS, Saez Calveras N, Stuve O. Microglia as a cellular target of diclofenac therapy in Alzheimer's disease. Ther Adv Neurol Disord 2023; 16:17562864231156674. [PMID: 36875711 PMCID: PMC9974624 DOI: 10.1177/17562864231156674] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 01/26/2023] [Indexed: 03/07/2023] Open
Abstract
Alzheimer's disease (AD) is an untreatable cause of dementia, and new therapeutic approaches are urgently needed. AD pathology is defined by extracellular amyloid plaques and intracellular neurofibrillary tangles. Research of the past decades has suggested that neuroinflammation plays a critical role in the pathophysiology of AD. This has led to the idea that anti-inflammatory treatments might be beneficial. Early studies investigated non-steroidal anti-inflammatory drugs (NSAIDS) such as indomethacin, celecoxib, ibuprofen, and naproxen, which had no benefit. More recently, protective effects of diclofenac and NSAIDs in the fenamate group have been reported. Diclofenac decreased the frequency of AD significantly compared to other NSAIDs in a large retrospective cohort study. Diclofenac and fenamates share similar chemical structures, and evidence from cell and mouse models suggests that they inhibit the release of pro-inflammatory mediators from microglia with leads to the reduction of AD pathology. Here, we review the potential role of diclofenac and NSAIDs in the fenamate group for targeting AD pathology with a focus on its potential effects on microglia.
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Affiliation(s)
- Barbara E Stopschinski
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Danni McMahan
- Pharmacy Service, Dallas VA Medical Center, Dallas, TX, USA
| | - David A Jacob
- Veterans Integrated Service Network 17, Arlington, TX, USA
| | - Bertis B Little
- School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA
| | - Hsueh-Sheng Chiang
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nil Saez Calveras
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Olaf Stuve
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Neurology Section, Dallas VA Medical Center, 4500 South Lancaster Road, Dallas, TX 75216, USA
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7
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Kenou BV, Manly LS, Rubovits SB, Umeozulu SA, Van Buskirk MG, Zhang AS, Pike VW, Zanotti-Fregonara P, Henter ID, Innis RB. Cyclooxygenases as Potential PET Imaging Biomarkers to Explore Neuroinflammation in Dementia. J Nucl Med 2022; 63:53S-59S. [PMID: 35649646 DOI: 10.2967/jnumed.121.263199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/12/2022] [Indexed: 12/18/2022] Open
Abstract
The most frequently studied target of neuroinflammation using PET is 18-kDa translocator protein, but its limitations have spurred the molecular imaging community to find more promising targets. This article reviews the development of PET radioligands for cyclooxygenase (COX) subtypes 1 and 2, enzymes that catalyze the production of inflammatory prostanoids in the periphery and brain. Although both isozymes produce the same precursor compound, prostaglandin H2, they have distinct functions based on their differential cellular localization in the periphery and brain. For example, COX-1 is located primarily in microglia, a resident inflammatory cell in the brain whose role in producing inflammatory cytokines is well documented. In contrast, COX-2 is located primarily in neurons and can be markedly upregulated by inflammatory and excitatory stimuli, but its functions are poorly understood. This article reviews these 2 isozymes as biomarkers of neuroinflammation, as well as the radioligands that have recently been developed to image them in animals and humans. To place this work into context, the properties of COX-1 and COX-2 are compared with 18-kDa translocator protein, with special consideration of their application in Alzheimer disease as a representative neurodegenerative disorder.
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Affiliation(s)
- Bruny V Kenou
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Lester S Manly
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Sara B Rubovits
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Somachukwu A Umeozulu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Maia G Van Buskirk
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Andrea S Zhang
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Ioline D Henter
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
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8
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Cao L, Kong Y, Ji B, Ren Y, Guan Y, Ni R. Positron Emission Tomography in Animal Models of Tauopathies. Front Aging Neurosci 2022; 13:761913. [PMID: 35082657 PMCID: PMC8784812 DOI: 10.3389/fnagi.2021.761913] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/30/2021] [Indexed: 12/18/2022] Open
Abstract
The microtubule-associated protein tau (MAPT) plays an important role in Alzheimer's disease and primary tauopathy diseases. The abnormal accumulation of tau contributes to the development of neurotoxicity, inflammation, neurodegeneration, and cognitive deficits in tauopathy diseases. Tau synergically interacts with amyloid-beta in Alzheimer's disease leading to detrimental consequence. Thus, tau has been an important target for therapeutics development for Alzheimer's disease and primary tauopathy diseases. Tauopathy animal models recapitulating the tauopathy such as transgenic, knock-in mouse and rat models have been developed and greatly facilitated the understanding of disease mechanisms. The advance in PET and imaging tracers have enabled non-invasive detection of the accumulation and spread of tau, the associated microglia activation, metabolic, and neurotransmitter receptor alterations in disease animal models. In vivo microPET studies on mouse or rat models of tauopathy have provided significant insights into the phenotypes and time course of pathophysiology of these models and allowed the monitoring of treatment targeting at tau. In this study, we discuss the utilities of PET and recently developed tracers for evaluating the pathophysiology in tauopathy animal models. We point out the outstanding challenges and propose future outlook in visualizing tau-related pathophysiological changes in brain of tauopathy disease animal models.
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Affiliation(s)
- Lei Cao
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- Changes Technology Corporation Ltd., Shanghai, China
| | - Yanyan Kong
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Bin Ji
- Department of Radiopharmacy and Molecular Imaging, School of Pharmacy, Fudan University, Shanghai, China
| | - Yutong Ren
- Guangdong Robotics Association, Guangzhou, China
| | - Yihui Guan
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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9
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Zhou R, Ji B, Kong Y, Qin L, Ren W, Guan Y, Ni R. PET Imaging of Neuroinflammation in Alzheimer's Disease. Front Immunol 2021; 12:739130. [PMID: 34603323 PMCID: PMC8481830 DOI: 10.3389/fimmu.2021.739130] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 08/27/2021] [Indexed: 12/15/2022] Open
Abstract
Neuroinflammation play an important role in Alzheimer's disease pathogenesis. Advances in molecular imaging using positron emission tomography have provided insights into the time course of neuroinflammation and its relation with Alzheimer's disease central pathologies in patients and in animal disease models. Recent single-cell sequencing and transcriptomics indicate dynamic disease-associated microglia and astrocyte profiles in Alzheimer's disease. Mitochondrial 18-kDa translocator protein is the most widely investigated target for neuroinflammation imaging. New generation of translocator protein tracers with improved performance have been developed and evaluated along with tau and amyloid imaging for assessing the disease progression in Alzheimer's disease continuum. Given that translocator protein is not exclusively expressed in glia, alternative targets are under rapid development, such as monoamine oxidase B, matrix metalloproteinases, colony-stimulating factor 1 receptor, imidazoline-2 binding sites, cyclooxygenase, cannabinoid-2 receptor, purinergic P2X7 receptor, P2Y12 receptor, the fractalkine receptor, triggering receptor expressed on myeloid cells 2, and receptor for advanced glycation end products. Promising targets should demonstrate a higher specificity for cellular locations with exclusive expression in microglia or astrocyte and activation status (pro- or anti-inflammatory) with highly specific ligand to enable in vivo brain imaging. In this review, we summarised recent advances in the development of neuroinflammation imaging tracers and provided an outlook for promising targets in the future.
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Affiliation(s)
- Rong Zhou
- Department of Nephrology, Yangpu Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Bin Ji
- Department of Radiopharmacy and Molecular Imaging, School of Pharmacy, Fudan University, Shanghai, China
| | - Yanyan Kong
- Positron Emission Tomography (PET) Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Limei Qin
- Inner Mongolia Baicaotang Qin Chinese Mongolia Hospital, Hohhot, China
| | - Wuwei Ren
- School of Information Science and Technology, Shanghaitech University, Shanghai, China
| | - Yihui Guan
- Positron Emission Tomography (PET) Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, University of Zurich & Eidgenössische Technische Hochschule Zürich (ETH Zurich), Zurich, Switzerland
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10
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Ghazanfari N, van Waarde A, Dierckx RAJO, Doorduin J, de Vries EFJ. Is cyclooxygenase-1 involved in neuroinflammation? J Neurosci Res 2021; 99:2976-2998. [PMID: 34346520 PMCID: PMC9542093 DOI: 10.1002/jnr.24934] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/08/2021] [Accepted: 07/13/2021] [Indexed: 12/15/2022]
Abstract
Purpose: Reactive microglia are an important hallmark of neuroinflammation. Reactive microglia release various inflammatory mediators, such as cytokines, chemokines, and prostaglandins, which are produced by enzymes like cyclooxygenases (COX). The inducible COX‐2 subtype has been associated with inflammation, whereas the constitutively expressed COX‐1 subtype is generally considered as a housekeeping enzyme. However, recent evidence suggests that COX‐1 can also be upregulated and may play a prominent role in the brain during neuroinflammation. In this review, we summarize the evidence that supports this involvement of COX‐1. Methods: Five databases were used to retrieve relevant studies that addressed COX‐1 in the context of neuroinflammation. The search resulted in 32 articles, describing in vitro, in vivo, post mortem, and in vivo imaging studies that specifically investigated the COX‐1 isoform under such conditions. Results: Reviewed literature generally indicated that the overexpression of COX‐1 was induced by an inflammatory stimulus, which resulted in an increased production of prostaglandin E2. The pharmacological inhibition of COX‐1 was shown to suppress the induction of inflammatory mediators like prostaglandin E2. Positron emission tomography (PET) imaging studies in animal models confirmed the overexpression of COX‐1 during neuroinflammation. The same imaging method, however, could not detect any upregulation of COX‐1 in patients with Alzheimer's disease. Conclusion: Taken together, studies in cultured cells and living rodents suggest that COX‐1 is involved in neuroinflammation. Most postmortem studies on human brains indicate that the concentration of COX‐1‐expressing microglial cells is increased near sites of inflammation. However, evidence for the involvement of COX‐1 in neuroinflammation in the living human brain is still largely lacking.
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Affiliation(s)
- Nafiseh Ghazanfari
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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Beaino W, Janssen B, Vugts DJ, de Vries HE, Windhorst AD. Towards PET imaging of the dynamic phenotypes of microglia. Clin Exp Immunol 2021; 206:282-300. [PMID: 34331705 PMCID: PMC8561701 DOI: 10.1111/cei.13649] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
There is increasing evidence showing the heterogeneity of microglia activation in neuroinflammatory and neurodegenerative diseases. It has been hypothesized that pro‐inflammatory microglia are detrimental and contribute to disease progression, while anti‐inflammatory microglia play a role in damage repair and remission. The development of therapeutics targeting the deleterious glial activity and modulating it into a regenerative phenotype relies heavily upon a clearer understanding of the microglia dynamics during disease progression and the ability to monitor therapeutic outcome in vivo. To that end, molecular imaging techniques are required to assess microglia dynamics and study their role in disease progression as well as to evaluate the outcome of therapeutic interventions. Positron emission tomography (PET) is such a molecular imaging technique, and provides unique capabilities for non‐invasive quantification of neuroinflammation and has the potential to discriminate between microglia phenotypes and define their role in the disease process. However, several obstacles limit the possibility for selective in vivo imaging of microglia phenotypes mainly related to the poor characterization of specific targets that distinguish the two ends of the microglia activation spectrum and lack of suitable tracers. PET tracers targeting translocator protein 18 kDa (TSPO) have been extensively explored, but despite the success in evaluating neuroinflammation they failed to discriminate between microglia activation statuses. In this review, we highlight the current knowledge on the microglia phenotypes in the major neuroinflammatory and neurodegenerative diseases. We also discuss the current and emerging PET imaging targets, the tracers and their potential in discriminating between the pro‐ and anti‐inflammatory microglia activation states.
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Affiliation(s)
- Wissam Beaino
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Bieneke Janssen
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Danielle J Vugts
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Helga E de Vries
- Department of Molecular Cell Biology and Immunology, MS Center Amsterdam, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
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12
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Hu SX, Ernst K, Benner CP, Feenstra KL. Stability of Ketoprofen Methylester in Plasma of Different Species. Curr Drug Metab 2021; 22:215-223. [PMID: 33334282 DOI: 10.2174/1389200221666201217141025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/30/2020] [Accepted: 11/04/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Pharmacokinetic and pharmacodynamic assessment of ester-containing drugs can be impacted by hydrolysis of the drugs in plasma samples post blood collection. The impact is different in the plasma of different species. OBJECTIVE This study evaluated the stability of a prodrug, ketoprofen methylester (KME), in commercially purchased and freshly collected plasma of mouse, rat, dog, cat, pig, sheep, cattle and horse. METHODS KME hydrolysis was determined following its incubation in commercially purchased and freshly collected plasma of those species. Different esterase inhibitors were evaluated for prevention of the hydrolysis in rat, dog and pig plasma. RESULTS KME was rapidly hydrolyzed in both commercially purchased and freshly collected plasma of mouse, rat, and horse. The hydrolysis was initially quick and then limited in cat plasma. KME hydrolysis was minimum in commercially purchased plasma of dog, pig, sheep and cattle but substantial in freshly collected plasma of those species. Different esterase inhibitors showed different effects on the stability of KME in rat, dog and pig plasma. CONCLUSION These results indicate that plasma of different species has different hydrolytic activities to estercontaining drugs. The activities in commercially purchased and freshly collected plasma may be different and species-dependent. Esterase inhibitors have different effects on preventing hydrolysis of the ester-containing drugs in the plasma of different species.
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Affiliation(s)
- Steven X Hu
- Zoetis, Inc., Veterinary Medicine Research and Development, Kalamazoo, MI 49007, United States
| | - Kelsey Ernst
- Zoetis, Inc., Veterinary Medicine Research and Development, Kalamazoo, MI 49007, United States
| | - Charles P Benner
- Zoetis, Inc., Veterinary Medicine Research and Development, Kalamazoo, MI 49007, United States
| | - Kenneth L Feenstra
- Zoetis, Inc., Veterinary Medicine Research and Development, Kalamazoo, MI 49007, United States
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13
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Taddei C, Morse CL, Kim MJ, Liow JS, Montero Santamaria J, Zhang A, Manly LS, Zanotti-Fregonara P, Gladding RL, Zoghbi SS, Innis RB, Pike VW. Synthesis of [ 18F]PS13 and Evaluation as a PET Radioligand for Cyclooxygenase-1 in Monkey. ACS Chem Neurosci 2021; 12:517-530. [PMID: 33491441 PMCID: PMC9021884 DOI: 10.1021/acschemneuro.0c00737] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cyclooxygenase-1 (COX-1) and its isozyme COX-2 are key enzymes in the syntheses of prostanoids. Imaging of COX-1 and COX-2 selective radioligands with positron emission tomography (PET) may clarify how these enzymes are involved in inflammatory conditions and assist in the discovery of improved anti-inflammatory drugs. We have previously labeled the selective high-affinity COX-1 ligand, 1,5-bis(4-methoxyphenyl)-3-(2,2,2-trifluoroethoxy)-1H-1,2,4-triazole (PS13), with carbon-11 (t1/2 = 20.4 min). This radioligand ([11C]PS13) has been successful for PET imaging of COX-1 in monkey and human brain and in periphery. [11C]PS13 is being used in clinical investigations. Alternative labeling of PS13 with fluorine-18 (t1/2 = 109.8 min) is desirable to provide a longer-lived radioligand in high activity that might be readily distributed among imaging centers. However, labeling of PS13 in its 1,1,1-trifluoroethoxy group is a radiochemical challenge. Here we assess two labeling approaches based on nucleophilic addition of cyclotron-produced [18F]fluoride ion to gem-difluorovinyl precursors, either to label PS13 in one step or to produce [18F]2,2,2-trifluoroethyl p-toluenesulfonate for labeling a hydroxyl precursor. From the latter two-step approach, we obtained [18F]PS13 ready for intravenous injection in a decay-corrected radiochemical yield of 7.9% and with a molar activity of up to 7.9 GBq/μmol. PET imaging of monkey brain with [18F]PS13 shows that this radioligand can specifically image and quantify COX-1 without radiodefluorination but with some radioactivity uptake in skull, ascribed to red bone marrow. The development of a new procedure for labeling PS13 with fluorine-18 at a higher molar activity is, however, desirable to suppress occupancy of COX-1 by carrier at baseline.
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Affiliation(s)
- Carlotta Taddei
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Min-Jeong Kim
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Jose Montero Santamaria
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Andrea Zhang
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Lester S Manly
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
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Schubert JJ, Veronese M, Fryer TD, Manavaki R, Kitzbichler MG, Nettis MA, Mondelli V, Pariante CM, Bullmore ET, Turkheimer FE. A Modest Increase in 11C-PK11195-Positron Emission Tomography TSPO Binding in Depression Is Not Associated With Serum C-Reactive Protein or Body Mass Index. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2021; 6:716-724. [PMID: 33515765 PMCID: PMC8264953 DOI: 10.1016/j.bpsc.2020.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/27/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023]
Abstract
Background Immune mechanisms have been implicated in the pathogenesis of depression. Translocator protein (TSPO)–targeted positron emission tomography (PET) has been used to assess neuroinflammation in major depressive disorder. We aimed to 1) test the hypothesis of significant case-control differences in TSPO binding in the anterior cingulate cortex, prefrontal cortex, and insula regions; and 2) explore the relationship between cerebral TSPO binding and peripheral blood C-reactive protein (CRP) concentration. Methods A total of 51 depressed subjects with Hamilton Depression Rating Scale score >13 (median 17; interquartile range, 16–22) and 25 healthy control subjects underwent dynamic brain 11C-PK11195 PET and peripheral blood immune marker characterization. Depressed subjects were divided into high CRP (>3 mg/L; n = 20) and low CRP (<3 mg/L; n = 31). Results Across the three regions, TSPO binding was significantly increased in depressed versus control subjects (η2p = .09; F1,71 = 6.97, p = .01), which was not influenced by body mass index. The case-control difference was greatest in the anterior cingulate cortex (d = 0.49; t74 = 2.00, p = .03) and not significant in the prefrontal cortex or insula (d = 0.27 and d = 0.36, respectively). Following CRP stratification, significantly higher TSPO binding was observed in low-CRP depression compared with controls (d = 0.53; t54 = 1.96, p = .03). These effect sizes are comparable to prior major depressive disorder case-control TSPO PET data. No significant correlations were observed between TSPO and CRP measures. Conclusions Consistent with previous findings, there is a modest increase in TSPO binding in depressed patients compared with healthy control subjects. The lack of a significant correlation between brain TSPO binding and blood CRP concentration or body mass index poses questions about the interactions between central and peripheral immune responses in the pathogenesis of depression.
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Affiliation(s)
- Julia J Schubert
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom.
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom
| | - Tim D Fryer
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom; Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Roido Manavaki
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Manfred G Kitzbichler
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Maria A Nettis
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom; National Institute for Health and Research Biomedical Research Centre, South London and Maudsley NHS Foundation Trust and King's College London, London, United Kingdom
| | - Valeria Mondelli
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom; National Institute for Health and Research Biomedical Research Centre, South London and Maudsley NHS Foundation Trust and King's College London, London, United Kingdom
| | - Carmine M Pariante
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom; National Institute for Health and Research Biomedical Research Centre, South London and Maudsley NHS Foundation Trust and King's College London, London, United Kingdom
| | - Edward T Bullmore
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom
| | - Federico E Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom
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15
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Abstract
This article presents an overview of imaging agents for PET that have been applied for research and diagnostic purposes in patients affected by dementia. Classified by the target which the agents visualize, seven groups of tracers can be distinguished, namely radiopharmaceuticals for: (1) Misfolded proteins (ß-amyloid, tau, α-synuclein), (2) Neuroinflammation (overexpression of translocator protein), (3) Elements of the cholinergic system, (4) Elements of monoamine neurotransmitter systems, (5) Synaptic density, (6) Cerebral energy metabolism (glucose transport/ hexokinase), and (7) Various other proteins. This last category contains proteins involved in mechanisms underlying neuroinflammation or cognitive impairment, which may also be potential therapeutic targets. Many receptors belong to this category: AMPA, cannabinoid, colony stimulating factor 1, metabotropic glutamate receptor 1 and 5 (mGluR1, mGluR5), opioid (kappa, mu), purinergic (P2X7, P2Y12), sigma-1, sigma-2, receptor for advanced glycation endproducts, and triggering receptor expressed on myeloid cells-1, besides several enzymes: cyclooxygenase-1 and 2 (COX-1, COX-2), phosphodiesterase-5 and 10 (PDE5, PDE10), and tropomyosin receptor kinase. Significant advances in neuroimaging have been made in the last 15 years. The use of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) for quantification of regional cerebral glucose metabolism is well-established. Three tracers for ß-amyloid plaques have been approved by the Food and Drug Administration and European Medicines Agency. Several tracers for tau neurofibrillary tangles are already applied in clinical research. Since many novel agents are in the preclinical or experimental stage of development, further advances in nuclear medicine imaging can be expected in the near future. PET studies with established tracers and tracers for novel targets may result in early diagnosis and better classification of neurodegenerative disorders and in accurate monitoring of therapy trials which involve these targets. PET data have prognostic value and may be used to assess the response of the human brain to interventions, or to select the appropriate treatment strategy for an individual patient.
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Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen, the Netherlands.
| | - Sofia Marcolini
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, the Netherlands
| | - Peter Paul de Deyn
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, the Netherlands; University of Antwerp, Born-Bunge Institute, Neurochemistry and Behavior, Campus Drie Eiken, Wilrijk, Belgium
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen, the Netherlands; Ghent University, Ghent, Belgium
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16
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Solnes LB, Jacobs AH, Coughlin JM, Du Y, Goel R, Hammoud DA, Pomper MG. Central Nervous System Molecular Imaging. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00088-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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17
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18
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Meyer JH, Cervenka S, Kim MJ, Kreisl WC, Henter ID, Innis RB. Neuroinflammation in psychiatric disorders: PET imaging and promising new targets. Lancet Psychiatry 2020; 7:1064-1074. [PMID: 33098761 PMCID: PMC7893630 DOI: 10.1016/s2215-0366(20)30255-8] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 01/14/2023]
Abstract
Neuroinflammation is a multifaceted physiological and pathophysiological response of the brain to injury and disease. Given imaging findings of 18 kDa translocator protein (TSPO) and the development of radioligands for other inflammatory targets, PET imaging of neuroinflammation is at a particularly promising stage. This Review critically evaluates PET imaging results of inflammation in psychiatric disorders, including major depressive disorder, schizophrenia and psychosis disorders, substance use, and obsessive-compulsive disorder. We also consider promising new targets that can be measured in the brain, such as monoamine oxidase B, cyclooxygenase-1 and cyclooxygenase-2, colony stimulating factor 1 receptor, and the purinergic P2X7 receptor. Thus far, the most compelling TSPO imaging results have arguably been found in major depressive disorder, for which consistent increases have been observed, and in schizophrenia and psychosis, for which patients show reduced TSPO levels. This pattern highlights the importance of validating brain biomarkers of neuroinflammation for each condition separately before moving on to patient stratification and treatment monitoring trials.
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Affiliation(s)
- Jeffrey H Meyer
- Campbell Family Mental Health Research Institute, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Simon Cervenka
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet and Stockholm Health Care Services, Stockholm, Sweden
| | - Min-Jeong Kim
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - William C Kreisl
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Ioline D Henter
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA.
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19
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Jain P, Chaney AM, Carlson ML, Jackson IM, Rao A, James ML. Neuroinflammation PET Imaging: Current Opinion and Future Directions. J Nucl Med 2020; 61:1107-1112. [PMID: 32620705 DOI: 10.2967/jnumed.119.229443] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Neuroinflammation is a key pathologic hallmark of numerous neurologic diseases, however, its exact role in vivo is yet to be fully understood. PET imaging enables investigation, quantification, and tracking of different neuroinflammation biomarkers in living subjects longitudinally. One such biomarker that has been imaged extensively using PET is translocator protein 18 kDa (TSPO). Although imaging TSPO has yielded valuable clinical data linking neuroinflammation to various neurodegenerative diseases, considerable limitations of TSPO PET have prompted identification of other more cell-specific and functionally relevant biomarkers. This review analyzes the clinical potential of available and emerging PET biomarkers of innate and adaptive immune responses, with mention of exciting future directions for the field.
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Affiliation(s)
- Poorva Jain
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Aisling M Chaney
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Mackenzie L Carlson
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California.,Department of Bioengineering, Stanford University, Stanford, California; and
| | - Isaac M Jackson
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Anoushka Rao
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Michelle L James
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California .,Department of Neurology and Neurological Sciences, Stanford University, Stanford, California
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20
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Meng F, Guo Z, Hu Y, Mai W, Zhang Z, Zhang B, Ge Q, Lou H, Guo F, Chen J, Duan S, Gao Z. CD73-derived adenosine controls inflammation and neurodegeneration by modulating dopamine signalling. Brain 2020; 142:700-718. [PMID: 30689733 DOI: 10.1093/brain/awy351] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 11/09/2018] [Accepted: 11/22/2018] [Indexed: 12/21/2022] Open
Abstract
Ectonucleotidase-mediated ATP catabolism provides a powerful mechanism to control the levels of extracellular adenosine. While increased adenosine A2A receptor (A2AR) signaling has been well-documented in both Parkinson's disease models and patients, the source of this enhanced adenosine signalling remains unclear. Here, we show that the ecto-5'-nucleotidase (CD73)-mediated adenosine formation provides an important input to activate A2AR, and upregulated CD73 and A2AR in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease models coordinatively contribute to the elevated adenosine signalling. Importantly, we demonstrate that CD73-derived adenosine-A2AR signalling modulates microglial immunoresponses and morphological dynamics. CD73 inactivation significantly attenuated lipopolysaccharide-induced pro-inflammatory responses in microglia, but enhanced microglia process extension, movement and morphological transformation in the laser injury and acute MPTP-induced Parkinson's disease models. Limiting CD73-derived adenosine substantially suppressed microglia-mediated neuroinflammation and improved the viability of dopaminergic neurons and motor behaviours in Parkinson's disease models. Moreover, CD73 inactivation suppressed A2AR induction and A2AR-mediated pro-inflammatory responses, whereas replenishment of adenosine analogues restored these effects, suggesting that CD73 produces a self-regulating feed-forward adenosine formation to activate A2AR and promote neuroinflammation. We further provide the first evidence that A2A enhanced inflammation by antagonizing dopamine-mediated anti-inflammation, suggesting that the homeostatic balance between adenosine and dopamine signalling is key to microglia immunoresponses. Our study thus reveals a novel role for CD73-mediated nucleotide metabolism in regulating neuroinflammation and provides the proof-of-principle that targeting nucleotide metabolic pathways to limit adenosine production and neuroinflammation in Parkinson's disease might be a promising therapeutic strategy.
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Affiliation(s)
- Fan Meng
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhige Guo
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yaling Hu
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Weihao Mai
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhenjie Zhang
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Bin Zhang
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Qianqian Ge
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Huifang Lou
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Fang Guo
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiangfan Chen
- Molecular Neuropharmacology Laboratory and State Key Laboratory of Optometry, Ophthalmology and Vision Science, School of Optometry and Ophthalmology, Wenzhou, Zhejiang, China
| | - Shumin Duan
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhihua Gao
- Department of Neurobiology and Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
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21
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Beaurain M, Salabert AS, Ribeiro MJ, Arlicot N, Damier P, Le Jeune F, Demonet JF, Payoux P. Innovative Molecular Imaging for Clinical Research, Therapeutic Stratification, and Nosography in Neuroscience. Front Med (Lausanne) 2019; 6:268. [PMID: 31828073 PMCID: PMC6890558 DOI: 10.3389/fmed.2019.00268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 11/01/2019] [Indexed: 01/06/2023] Open
Abstract
Over the past few decades, several radiotracers have been developed for neuroimaging applications, especially in PET. Because of their low steric hindrance, PET radionuclides can be used to label molecules that are small enough to cross the blood brain barrier, without modifying their biological properties. As the use of 11C is limited by its short physical half-life (20 min), there has been an increasing focus on developing tracers labeled with 18F for clinical use. The first such tracers allowed cerebral blood flow and glucose metabolism to be measured, and the development of molecular imaging has since enabled to focus more closely on specific targets such as receptors, neurotransmitter transporters, and other proteins. Hence, PET and SPECT biomarkers have become indispensable for innovative clinical research. Currently, the treatment options for a number of pathologies, notably neurodegenerative diseases, remain only supportive and symptomatic. Treatments that slow down or reverse disease progression are therefore the subject of numerous studies, in which molecular imaging is proving to be a powerful tool. PET and SPECT biomarkers already make it possible to diagnose several neurological diseases in vivo and at preclinical stages, yielding topographic, and quantitative data about the target. As a result, they can be used for assessing patients' eligibility for new treatments, or for treatment follow-up. The aim of the present review was to map major innovative radiotracers used in neuroscience, and explain their contribution to clinical research. We categorized them according to their target: dopaminergic, cholinergic or serotoninergic systems, β-amyloid plaques, tau protein, neuroinflammation, glutamate or GABA receptors, or α-synuclein. Most neurological disorders, and indeed mental disorders, involve the dysfunction of one or more of these targets. Combinations of molecular imaging biomarkers can afford us a better understanding of the mechanisms underlying disease development over time, and contribute to early detection/screening, diagnosis, therapy delivery/monitoring, and treatment follow-up in both research and clinical settings.
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Affiliation(s)
- Marie Beaurain
- CHU de Toulouse, Toulouse, France.,ToNIC, Toulouse NeuroImaging Center, Inserm U1214, Toulouse, France
| | - Anne-Sophie Salabert
- CHU de Toulouse, Toulouse, France.,ToNIC, Toulouse NeuroImaging Center, Inserm U1214, Toulouse, France
| | - Maria Joao Ribeiro
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.,Inserm CIC 1415, University Hospital, Tours, France.,CHRU Tours, Tours, France
| | - Nicolas Arlicot
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.,Inserm CIC 1415, University Hospital, Tours, France.,CHRU Tours, Tours, France
| | - Philippe Damier
- Inserm U913, Neurology Department, University Hospital, Nantes, France
| | | | - Jean-François Demonet
- Leenards Memory Centre, Department of Clinical Neuroscience, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Pierre Payoux
- CHU de Toulouse, Toulouse, France.,ToNIC, Toulouse NeuroImaging Center, Inserm U1214, Toulouse, France
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22
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Shrestha S, Singh P, Cortes-Salva MY, Jenko KJ, Ikawa M, Kim MJ, Kobayashi M, Morse CL, Gladding RL, Liow JS, Zoghbi SS, Fujita M, Innis RB, Pike VW. 3-Substituted 1,5-Diaryl-1 H-1,2,4-triazoles as Prospective PET Radioligands for Imaging Brain COX-1 in Monkey. Part 2: Selection and Evaluation of [ 11C]PS13 for Quantitative Imaging. ACS Chem Neurosci 2018; 9:2620-2627. [PMID: 29792035 DOI: 10.1021/acschemneuro.8b00103] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In our preceding paper (Part 1), we identified three 1,5-bis-diaryl-1,2,4-triazole-based compounds that merited evaluation as potential positron emission tomography (PET) radioligands for selectively imaging cyclooxygenase-1 (COX-1) in monkey and human brain, namely, 1,5-bis(4-methoxyphenyl)-3-(alkoxy)-1 H-1,2,4-triazoles bearing a 3-methoxy (PS1), a 3-(2,2,2-trifluoroethoxy) (PS13), or a 3-fluoromethoxy substituent (PS2). PS1 and PS13 were labeled from phenol precursors by O-11C-methylation with [11C]iodomethane and PS2 by O-18F-fluoroalkylation with [2H2,18F]fluorobromomethane. Here, we evaluated these PET radioligands in monkey. All three radioligands gave moderately high uptake in brain, although [2H2,18F]PS2 also showed undesirable radioactivity uptake in skull. [11C]PS13 was selected for further evaluation, mainly based on more favorable brain kinetics than [11C]PS1. Pharmacological preblock experiments showed that about 55% of the radioactivity uptake in brain was specifically bound to COX-1. An index of enzyme density, VT, was well identified from serial brain scans and from the concentrations of parent radioligand in arterial plasma. In addition, VT values were stable within 80 min, suggesting that brain uptake was not contaminated by radiometabolites. [11C]PS13 successfully images and quantifies COX-1 in monkey brain, and merits further investigation for imaging COX-1 in monkey models of neuroinflammation and in healthy human subjects.
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Affiliation(s)
- Stal Shrestha
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Prachi Singh
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Michelle Y. Cortes-Salva
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Kimberly J. Jenko
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Masamichi Ikawa
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Min-Jeong Kim
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Masato Kobayashi
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Cheryl L. Morse
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Robert L. Gladding
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Sami S. Zoghbi
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Robert B. Innis
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Victor W. Pike
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
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Singh P, Shrestha S, Cortes-Salva MY, Jenko KJ, Zoghbi SS, Morse CL, Innis RB, Pike VW. 3-Substituted 1,5-Diaryl-1 H-1,2,4-triazoles as Prospective PET Radioligands for Imaging Brain COX-1 in Monkey. Part 1: Synthesis and Pharmacology. ACS Chem Neurosci 2018; 9:2610-2619. [PMID: 29678105 DOI: 10.1021/acschemneuro.8b00102] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cyclooxygenase-1 (COX-1) is a key enzyme in the biosynthesis of proinflammatory thromboxanes and prostaglandins and is found in glial and neuronal cells within brain. COX-1 expression is implicated in numerous neuroinflammatory states. We aim to find a direct-acting positron emission tomography (PET) radioligand for imaging COX-1 in human brain as a potential biomarker of neuroinflammation and for serving as a tool in drug development. Seventeen 3-substituted 1,5-diaryl-1 H-1,2,4-triazoles were prepared as prospective COX-1 PET radioligands. From this set, three 1,5-(4-methoxyphenyl)-1 H-1,2,4-triazoles, carrying a 3-methoxy (5), 3-(1,1,1-trifluoroethoxy) (20), or 3-fluoromethoxy substituent (6), were selected for radioligand development, based mainly on their high affinities and selectivities for inhibiting human COX-1, absence of carboxyl group, moderate computed lipophilicities, and scope for radiolabeling with carbon-11 ( t1/2 = 20.4 min) or fluorine-18 ( t1/2 = 109.8 min). Methods were developed for producing [11C]5, [11C]20, and [ d2-18F]6 from hydroxy precursors in a form ready for intravenous injection for prospective evaluation in monkey with PET.
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Affiliation(s)
- Prachi Singh
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Stal Shrestha
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Michelle Y. Cortes-Salva
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Kimberly J. Jenko
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Sami S. Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Cheryl L. Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Robert B. Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
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24
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Högel H, Rissanen E, Vuorimaa A, Airas L. Positron emission tomography imaging in evaluation of MS pathology in vivo. Mult Scler 2018; 24:1399-1412. [DOI: 10.1177/1352458518791680] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Positron emission tomography (PET) gives an opportunity to quantitate the expression of specific molecular targets in vivo and longitudinally in brain and thus enhances our possibilities to understand and follow up multiple sclerosis (MS)-related pathology. For successful PET imaging, one needs a relevant target molecule within the brain, to which a blood–brain barrier–penetrating specific radioligand will bind. 18-kDa translocator protein (TSPO)-binding radioligands have been used to detect activated microglial cells at different stages of MS, and remyelination has been measured using amyloid PET. Several PET ligands for the detection of other inflammatory targets, besides TSPO, have been developed but not yet been used for imaging MS patients. Finally, synaptic density evaluation has been successfully tested in human subjects and gives opportunities for the evaluation of the development of cortical and deep gray matter pathology in MS. This review will discuss PET imaging modalities relevant for MS today.
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Affiliation(s)
- Heidi Högel
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Anna Vuorimaa
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Laura Airas
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
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25
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Hierro-Bujalance C, Bacskai BJ, Garcia-Alloza M. In Vivo Imaging of Microglia With Multiphoton Microscopy. Front Aging Neurosci 2018; 10:218. [PMID: 30072888 PMCID: PMC6060250 DOI: 10.3389/fnagi.2018.00218] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/26/2018] [Indexed: 01/04/2023] Open
Abstract
Neuroimaging has become an unparalleled tool to understand the central nervous system (CNS) anatomy, physiology and neurological diseases. While an altered immune function and microglia hyperactivation are common neuropathological features for many CNS disorders and neurodegenerative diseases, direct assessment of the role of microglial cells remains a challenging task. Non-invasive neuroimaging techniques, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single positron emission computed tomography (SPECT) are widely used for human clinical applications, and a variety of ligands are available to detect neuroinflammation. In animal models, intravital imaging has been largely used, and minimally invasive multiphoton microcopy (MPM) provides high resolution detection of single microglia cells, longitudinally, in living brain. In this study, we review in vivo real-time MPM approaches to assess microglia in preclinical studies, including individual cell responses in surveillance, support, protection and restoration of brain tissue integrity, synapse formation, homeostasis, as well as in different pathological situations. We focus on in vivo studies that assess the role of microglia in mouse models of Alzheimer’s disease (AD), analyzing microglial motility and recruitment, as well as the role of microglia in anti-amyloid-β treatment, as a key therapeutic approach to treat AD. Altogether, MPM provides a high contrast and high spatial resolution approach to follow microglia chronically in vivo in complex models, supporting MPM as a powerful tool for deep intravital tissue imaging.
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Affiliation(s)
- Carmen Hierro-Bujalance
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Monica Garcia-Alloza
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
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26
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Kim MJ, Shrestha SS, Cortes M, Singh P, Morse C, Liow JS, Gladding RL, Brouwer C, Henry K, Gallagher E, Tye GL, Zoghbi SS, Fujita M, Pike VW, Innis RB. Evaluation of Two Potent and Selective PET Radioligands to Image COX-1 and COX-2 in Rhesus Monkeys. J Nucl Med 2018; 59:1907-1912. [PMID: 29959215 DOI: 10.2967/jnumed.118.211144] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/01/2018] [Indexed: 12/18/2022] Open
Abstract
This study assessed whether the newly developed PET radioligands 11C-PS13 and 11C-MC1 could image constitutive levels of cyclooxygenase (COX)-1 and COX-2, respectively, in rhesus monkeys. Methods: After intravenous injection of either radioligand, 24 whole-body PET scans were performed. To measure enzyme-specific uptake, scans of the 2 radioligands were also performed after administration of a nonradioactive drug preferential for either COX-1 or COX-2. Concurrent venous samples were obtained to measure parent radioligand concentrations. SUVs were calculated from 10 to 90 min. Results: 11C-PS13 showed specific uptake in most organs, including spleen, gastrointestinal tract, kidneys, and brain, which was blocked by COX-1, but not COX-2, preferential inhibitors. Specific uptake of 11C-MC1 was not observed in any organ except the ovaries and possibly kidneys. Conclusion: The findings suggest that 11C-PS13 has adequate signal in monkeys to justify its extension to human subjects. In contrast, 11C-MC1 is unlikely to show significant signal in healthy humans, though it may be able to do so in inflammatory conditions.
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Affiliation(s)
- Min-Jeong Kim
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Stal S Shrestha
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Michelle Cortes
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Prachi Singh
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Cheryl Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Chad Brouwer
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Katharine Henry
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Evan Gallagher
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - George L Tye
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
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27
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Lagarde J, Sarazin M, Bottlaender M. In vivo PET imaging of neuroinflammation in Alzheimer's disease. J Neural Transm (Vienna) 2017; 125:847-867. [PMID: 28516240 DOI: 10.1007/s00702-017-1731-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/01/2017] [Indexed: 12/15/2022]
Abstract
Increasing evidence suggests that neuroinflammation contributes to the pathophysiology of many neurodegenerative diseases, especially Alzheimer's disease (AD). Molecular imaging by PET may be a useful tool to assess neuroinflammation in vivo, thus helping to decipher the complex role of inflammatory processes in the pathophysiology of neurodegenerative diseases and providing a potential means of monitoring the effect of new therapeutic approaches. For this objective, the main target of PET studies is the 18 kDa translocator protein (TSPO), as it is overexpressed by activated microglia. In the present review, we describe the most widely used PET tracers targeting the TSPO, the methodological issues in tracer quantification and summarize the results obtained by TSPO PET imaging in AD, as well as in neurodegenerative disorders associated with AD, in psychiatric disorders and ageing. We also briefly describe alternative PET targets and imaging modalities to study neuroinflammation. Lastly, we question the meaning of PET imaging data in the context of a highly complex and multifaceted role of neuroinflammation in neurodegenerative diseases. This overview leads to the conclusion that PET imaging of neuroinflammation is a promising way of deciphering the enigma of the pathophysiology of AD and of monitoring the effect of new therapies.
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Affiliation(s)
- Julien Lagarde
- Unit of Neurology of Memory and Language, Centre de Psychiatrie et Neurosciences, INSERM UMR S894, Centre Hospitalier Sainte-Anne and Université Paris Descartes, Sorbonne Paris Cité, 75014, Paris, France
| | - Marie Sarazin
- Unit of Neurology of Memory and Language, Centre de Psychiatrie et Neurosciences, INSERM UMR S894, Centre Hospitalier Sainte-Anne and Université Paris Descartes, Sorbonne Paris Cité, 75014, Paris, France
| | - Michel Bottlaender
- UNIACT, NeuroSpin, Institut d'Imagerie Biomédicale, Direction de la Recherche Fondamentale, Commissariat à l'Energie Atomique, 91191, Gif-sur-Yvette, France. .,Laboratoire Imagerie Moléculaire in Vivo, UMR 1023, Service Hospitalier Frédéric Joliot, Institut d'Imagerie Biomédicale, Direction de la Recherche Fondamentale, Commissariat à l'Energie Atomique, 91400, Orsay, France.
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28
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Schain M, Kreisl WC. Neuroinflammation in Neurodegenerative Disorders—a Review. Curr Neurol Neurosci Rep 2017; 17:25. [DOI: 10.1007/s11910-017-0733-2] [Citation(s) in RCA: 187] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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