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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 2024:00006396-990000000-00597. [PMID: 38713812 DOI: 10.1097/j.pain.0000000000003247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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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2
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Zirbesegger K, Reyes L, Paolino A, Dapueto R, Arredondo F, Gambini JP, Savio E, Porcal W. Molecular Imaging of Monoamine Oxidase A Expression in Highly Aggressive Prostate Cancer: Synthesis and Preclinical Evaluation of Positron Emission Tomography Tracers. ACS Pharmacol Transl Sci 2023; 6:1734-1744. [PMID: 37982127 PMCID: PMC10653014 DOI: 10.1021/acsptsci.3c00175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 11/21/2023]
Abstract
The role of monoamine oxidase A (MAO-A) in the aggressiveness of prostate cancer (PCa) has been established in recent years. The molecular imaging of MAO-A expression could offer a noninvasive tool for the visualization and quantification of highly aggressive PCa. This study reports the synthesis and preclinical evaluation of 11C- and 18F-labeled MAO-A inhibitors as positron emission tomography (PET) tracers for proof-of-concept studies in animal models of PCa. Good manufacturing practice production and quality control of these radiotracers using an automated platform was achieved. PET imaging was performed in an LNCaP tumor model with high MAO-A expression. The tumor-to-muscle (T/M) uptake ratio of [11C]harmine (4.5 ± 0.5) was significantly higher than that for 2-[18F]fluoroethyl-harmol (2.3 ± 0.7) and [11C]clorgyline (2.0 ± 0.1). A comparable ex vivo biodistribution pattern in all radiotracers was observed. Furthermore, the tumor uptake of [11C]harmine showed a dramatic reduction (T/M = 1) in a PC3 tumor model with limited MAO-A expression, and radioactivity uptake in LNCaP tumors was blocked in the presence of nonradioactive harmine. Our findings suggest that [11C]harmine may serve as an attractive PET probe for the visualization of MAO-A expression in highly aggressive PCa. These radiotracers have the potential for clinical translation and may aid in the development of personalized therapeutic strategies for PCa patients.
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Affiliation(s)
- Kevin Zirbesegger
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
- Programa de Posgrado, Facultad de Química, Universidad de la República, Av. General Flores 2124, 11800 Montevideo, Uruguay
| | - Laura Reyes
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
| | - Andrea Paolino
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
| | - Rosina Dapueto
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
| | - Florencia Arredondo
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
| | - Juan P Gambini
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
| | - Eduardo Savio
- Centro Uruguayo de Imagenología Molecular (CUDIM), Ricaldoni 2010, 11600 Montevideo, Uruguay
| | - Williams Porcal
- Departamento de Química Orgánica, Facultad de Química, Universidad de la República, Av. General Flores 2124, 11800 Montevideo, Uruguay
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3
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Liu S, Qiu W, Li R, Chen B, Wu X, Magnuson JT, Xu B, Luo S, Xu EG, Zheng C. Perfluorononanoic Acid Induces Neurotoxicity via Synaptogenesis Signaling in Zebrafish. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3783-3793. [PMID: 36797597 DOI: 10.1021/acs.est.2c06739] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Perfluorononanoic acid (PFNA), commonly used as an alternative polyfluorinated compound (PFC) of perfluorooctanoic acid (PFOA), has been widely detected in the aquatic environment. Previous ecotoxicological and epidemiological results suggested that some neurobehavioral effects were associated with PFC exposure; however, the ecological impacts and underlying neurotoxicity mechanisms remain unclear, particularly in aquatic organisms during sensitive, early developmental stages. In this study, zebrafish embryos were exposed to environmentally relevant concentrations of PFNA for 120 h, and the neurological effects of PFNA were comprehensively assessed using transcriptional, biochemical, morphological, and behavioral assays. RNA sequencing and advanced bioinformatics analyses predicted and characterized the key biological processes and pathways affected by PFNA exposure, which included the synaptogenesis signaling pathway, neurotransmitter synapse, and CREB signaling in neurons. Neurotransmitter levels (acetylcholine, glutamate, 5-hydroxytryptamine, γ-aminobutyric acid, dopamine, and noradrenaline) were significantly decreased in zebrafish larvae, and the Tg(gad67:GFP) transgenic line revealed a decreased number of GABAergic neurons in PFNA-treated larvae. Moreover, the swimming distance, rotation frequency, and activity degree were also significantly affected by PFNA, linking molecular-level changes to behavioral consequences.
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Affiliation(s)
- Shuai Liu
- Institute of Microbiology, Jiangxi Academy of Sciences, Changdong Avenue 7777, Qingshan Lake District, Nanchang 330012, China
| | - Wenhui Qiu
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Xueyuandadao 1088, Nanshan District, Shenzhen 518055, China
| | - Rongzhen Li
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Xueyuandadao 1088, Nanshan District, Shenzhen 518055, China
| | - Bei Chen
- Fisheries Research Institute of Fujian, Haishan Road 7, Huli District, Xiamen 361000, China
| | - Xin Wu
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Xueyuandadao 1088, Nanshan District, Shenzhen 518055, China
| | - Jason T Magnuson
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, Måltidets Hus-Richard Johnsens gate 4, Stavanger 4021, Norway
| | - Bentuo Xu
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, School of Life and Environmental Science, Wenzhou University, Chashan University Town, Wenzhou 325035, China
| | - Shusheng Luo
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Xueyuandadao 1088, Nanshan District, Shenzhen 518055, China
| | - Elvis Genbo Xu
- Department of Biology, University of Southern Denmark, Campusvej 55, Odense 5230, Denmark
| | - Chunmiao Zheng
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Xueyuandadao 1088, Nanshan District, Shenzhen 518055, China
- EIT Institute for Advanced Study, Tongxin Road 568, Zhenhai District, Ningbo 315200, China
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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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Singh P, Singh D, Srivastava P, Mishra G, Tiwari AK. Evaluation of advanced, pathophysiologic new targets for imaging of CNS. Drug Dev Res 2023; 84:484-513. [PMID: 36779375 DOI: 10.1002/ddr.22040] [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: 10/23/2022] [Revised: 12/12/2022] [Accepted: 12/31/2022] [Indexed: 02/14/2023]
Abstract
The inadequate information about the in vivo pathological, physiological, and neurological impairments, as well as the absence of in vivo tools for assessing brain penetrance and the efficiency of newly designed drugs, has hampered the development of new techniques for the treatment for variety of new central nervous system (CNS) diseases. The searching sites such as Science Direct and PubMed were used to find out the numerous distinct tracers across 16 CNS targets including tau, synaptic vesicle glycoprotein, the adenosine 2A receptor, the phosphodiesterase enzyme PDE10A, and the purinoceptor, among others. Among the most encouraging are [18 F]FIMX for mGluR imaging, [11 C]Martinostat for Histone deacetylase, [18 F]MNI-444 for adenosine 2A imaging, [11 C]ER176 for translocator protein, and [18 F]MK-6240 for tau imaging. We also reviewed the findings for each tracer's features and potential for application in CNS pathophysiology and therapeutic evaluation investigations, including target specificity, binding efficacy, and pharmacokinetic factors. This review aims to present a current evaluation of modern positron emission tomography tracers for CNS targets, with a focus on recent advances for targets that have newly emerged for imaging in humans.
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Affiliation(s)
- Priya Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Deepika Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Pooja Srivastava
- Division of Cyclotron and Radiopharmaceuticals Sciences, Institute of Nuclear Medicine and Allied Sciences, Delhi, India
| | - Gauri Mishra
- Department of Zoology, Swami Shraddhananad College, University of Delhi, Alipur, Delhi, India
| | - Anjani K Tiwari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
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6
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Lopresti BJ, Royse SK, Mathis CA, Tollefson SA, Narendran R. Beyond monoamines: I. Novel targets and radiotracers for Positron emission tomography imaging in psychiatric disorders. J Neurochem 2023; 164:364-400. [PMID: 35536762 DOI: 10.1111/jnc.15615] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 10/18/2022]
Abstract
With the emergence of positron emission tomography (PET) in the late 1970s, psychiatry had access to a tool capable of non-invasive assessment of human brain function. Early applications in psychiatry focused on identifying characteristic brain blood flow and metabolic derangements using radiotracers such as [15 O]H2 O and [18 F]FDG. Despite the success of these techniques, it became apparent that more specific probes were needed to understand the neurochemical bases of psychiatric disorders. The first neurochemical PET imaging probes targeted sites of action of neuroleptic (dopamine D2 receptors) and psychoactive (serotonin receptors) drugs. Based on the centrality of monoamine dysfunction in psychiatric disorders and the measured success of monoamine-enhancing drugs in treating them, the next 30 years witnessed the development of an armamentarium of PET radiopharmaceuticals and imaging methodologies for studying monoamines. Continued development of monoamine-enhancing drugs over this time however was less successful, realizing only modest gains in efficacy and tolerability. As patent protection for many widely prescribed and profitable psychiatric drugs lapsed, drug development pipelines shifted away from monoamines in search of novel targets with the promises of improved efficacy, or abandoned altogether. Over this period, PET radiopharmaceutical development activities closely paralleled drug development priorities resulting in the development of new PET imaging agents for non-monoamine targets. Part one of this review will briefly survey novel PET imaging targets with relevance to the field of psychiatry, which include the metabotropic glutamate receptor type 5 (mGluR5), purinergic P2 X7 receptor, type 1 cannabinoid receptor (CB1 ), phosphodiesterase 10A (PDE10A), and describe radiotracers developed for these and other targets that have matured to human subject investigations. Current limitations of the targets and techniques will also be discussed.
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Affiliation(s)
- Brian J Lopresti
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah K Royse
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chester A Mathis
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Savannah A Tollefson
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rajesh Narendran
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Departments of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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7
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Edinoff AN, Swinford CR, Odisho AS, Burroughs CR, Stark CW, Raslan WA, Cornett EM, Kaye AM, Kaye AD. Clinically Relevant Drug Interactions with Monoamine Oxidase Inhibitors. Health Psychol Res 2022; 10:39576. [PMID: 36425231 PMCID: PMC9680847 DOI: 10.52965/001c.39576] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2023] Open
Abstract
Monoamine oxidase inhibitors (MAOI) are a class of drugs that were originally developed for the treatment of depression but have since been expanded to be used in management of affective and neurological disorders, as well as stroke and aging-related neurocognitive changes. Ranging from irreversible to reversible and selective to non-selective, these drugs target the monoamine oxidase (MAO) enzyme and prevent the oxidative deamination of various monoamines and catecholamines such as serotonin and dopamine, respectively. Tyramine is a potent releaser of norepinephrine (NE) and is found in high concentrations in foods such as aged cheeses and meats. Under normal conditions, NE is unable to accumulate to toxic levels due to the presence of MAO-A, an enzyme that degrades neurotransmitters, including NE. When MAO-A is inhibited, the capacity to handle tyramine intake from the diet is significantly reduced causing the brain to be vulnerable to overstimulation of postsynaptic adrenergic receptors with as little as 8-10 mg of tyramine ingested and can result in life-threatening blood pressure elevations. In addition to adverse reactions with certain foods, both older and newer MAOIs can negatively interact with both sympathomimetic and serotonergic drugs. In general, patients on a MAOI want to avoid two types of medications: those that can elevate blood pressure via sympathomimetic actions (e.g., phenylephrine and oxymetazoline) and those that can increase serotonin levels via 5-HT reuptake inhibition (e.g., dextromethorphan, chlorpheniramine, and brompheniramine). Illicit drugs that stimulate the central nervous system such as ecstasy (MDMA, 3,4-methylenedioxymethamphetamine) act as serotonin releasers. Patient involvement is also crucial to ensure any interaction within the healthcare setting includes making other providers aware of a MAOI prescription as well as avoiding certain OTC medications that can interact adversely with MAOIs.
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Affiliation(s)
- Amber N Edinoff
- Department of Psychiatry, Harvard Medical School, Massachusetts General Hospital
| | - Connor R Swinford
- Department of Psychiatry and Behavioral Medicine, Louisiana State University Health Science Center Shreveport
| | - Amira S Odisho
- Department of Psychiatry and Behavioral Medicine, Louisiana State University Health Science Center Shreveport
| | | | - Cain W Stark
- School of Medicine, Louisiana State University Health Science Center Shreveport
| | | | - Elyse M Cornett
- Department of Anesthesiology, Louisiana State University Health Science Center Shreveport
| | - Adam M Kaye
- Department of Pharmacy Practice, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific
| | - Alan D Kaye
- Department of Anesthesiology, Louisiana State University Health Science Center Shreveport
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8
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Wang Y, Lin Q, Shi H, Cheng D. Fluorine-18: Radiochemistry and Target-Specific PET Molecular Probes Design. Front Chem 2022; 10:884517. [PMID: 35844642 PMCID: PMC9277085 DOI: 10.3389/fchem.2022.884517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/19/2022] [Indexed: 12/02/2022] Open
Abstract
The positron emission tomography (PET) molecular imaging technology has gained universal value as a critical tool for assessing biological and biochemical processes in living subjects. The favorable chemical, physical, and nuclear characteristics of fluorine-18 (97% β+ decay, 109.8 min half-life, 635 keV positron energy) make it an attractive nuclide for labeling and molecular imaging. It stands that 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) is the most popular PET tracer. Besides that, a significantly abundant proportion of PET probes in clinical use or under development contain a fluorine or fluoroalkyl substituent group. For the reasons given above, 18F-labeled radiotracer design has become a hot topic in radiochemistry and radiopharmaceutics. Over the past decades, we have witnessed a rapid growth in 18F-labeling methods owing to the development of new reagents and catalysts. This review aims to provide an overview of strategies in radiosynthesis of [18F]fluorine-containing moieties with nucleophilic [18F]fluorides since 2015.
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Affiliation(s)
- Yunze Wang
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
- Institute of Nuclear Medicine, Fudan University, Shanghai, China
- Shanghai Institute of Medical Imaging, Shanghai, China
| | - Qingyu Lin
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
- Institute of Nuclear Medicine, Fudan University, Shanghai, China
- Shanghai Institute of Medical Imaging, Shanghai, China
| | - Hongcheng Shi
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
- Institute of Nuclear Medicine, Fudan University, Shanghai, China
- Shanghai Institute of Medical Imaging, Shanghai, China
| | - Dengfeng Cheng
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
- Institute of Nuclear Medicine, Fudan University, Shanghai, China
- Shanghai Institute of Medical Imaging, Shanghai, China
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9
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Harada R, Furumoto S, Kudo Y, Yanai K, Villemagne VL, Okamura N. Imaging of Reactive Astrogliosis by Positron Emission Tomography. Front Neurosci 2022; 16:807435. [PMID: 35210989 PMCID: PMC8862631 DOI: 10.3389/fnins.2022.807435] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
Many neurodegenerative diseases are neuropathologically characterized by neuronal loss, gliosis, and the deposition of misfolded proteins such as β-amyloid (Aβ) plaques and tau tangles in Alzheimer’s disease (AD). In postmortem AD brains, reactive astrocytes and activated microglia are observed surrounding Aβ plaques and tau tangles. These activated glial cells secrete pro-inflammatory cytokines and reactive oxygen species, which may contribute to neurodegeneration. Therefore, in vivo imaging of glial response by positron emission tomography (PET) combined with Aβ and tau PET would provide new insights to better understand the disease process, as well as aid in the differential diagnosis, and monitoring glial response disease-specific therapeutics. There are two promising targets proposed for imaging reactive astrogliosis: monoamine oxidase-B (MAO-B) and imidazoline2 binding site (I2BS), which are predominantly expressed in the mitochondrial membranes of astrocytes and are upregulated in various neurodegenerative conditions. PET tracers targeting these two MAO-B and I2BS have been evaluated in humans. [18F]THK-5351, which was originally designed to target tau aggregates in AD, showed high affinity for MAO-B and clearly visualized reactive astrocytes in progressive supranuclear palsy (PSP). However, the lack of selectivity of [18F]THK-5351 binding to both MAO-B and tau, severely limits its clinical utility as a biomarker. Recently, [18F]SMBT-1 was developed as a selective and reversible MAO-B PET tracer via compound optimization of [18F]THK-5351. In this review, we summarize the strategy underlying molecular imaging of reactive astrogliosis and clinical studies using MAO-B and I2BS PET tracers.
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Affiliation(s)
- Ryuichi Harada
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
- *Correspondence: Ryuichi Harada,
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Yukitsuka Kudo
- Department of New Therapeutics Innovation for Alzheimer’s and Dementia, Institute of Development and Aging, Tohoku University, Sendai, Japan
| | - Kazuhiko Yanai
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Victor L. Villemagne
- Department of Molecular Imaging and Therapy, Austin Health, Melbourne, VIC, Australia
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Nobuyuki Okamura
- Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
- Nobuyuki Okamura,
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10
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Sakala K, Kasearu K, Katus U, Veidebaum T, Harro J. Association between platelet MAO activity and lifetime drug use in a longitudinal birth cohort study. Psychopharmacology (Berl) 2022; 239:327-337. [PMID: 35001146 DOI: 10.1007/s00213-021-06035-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/22/2021] [Indexed: 12/12/2022]
Abstract
RATIONALE Platelet monoamine oxidase (MAO) activity, a marker of central serotonergic capacity, has been associated with a variety of problem behaviours. However, studies on platelet MAO activity and addictive drugs have not consistently linked MAO activity with addiction or reported to predict illicit substance use initiation or frequency. OBJECTIVES Platelet MAO activity and illicit drug use was examined in a longitudinal birth cohort study. METHODS The sample included both birth cohorts (original n = 1238) of the Estonian Children Personality Behaviour and Health Study. Longitudinal association from age 15 to 25 years between platelet MAO activity and lifetime drug use was analysed by mixed-effects regression models. Differences at ages 15, 18 and 25 were analysed by t-test. Cox proportional hazard regression analysis was used to assess the association between platelet MAO activity and the age of drug use initiation. RESULTS Male subjects who reported at least one drug use event had lower platelet MAO activity compared to nonusers, both in cross-sectional and longitudinal analyses. Males with low platelet MAO activity had started to use drugs at a younger age. Moreover, in male subjects who had experimented with illicit drugs only once in lifetime, low platelet MAO activity was also associated with higher risk at a younger age. In females, platelet MAO activity was not associated with drug use. CONCLUSION In males, low platelet MAO activity is associated with drug abuse primarily owing to risk-taking at early age.
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Affiliation(s)
- Katre Sakala
- Department of Chronic Diseases, National Institute for Health Development, Hiiu 42, 11619, Tallinn, Estonia.,Institute of Family Medicine and Public Health, Faculty of Medicine, University of Tartu, Ravila 19, 50411, Tartu, Estonia.,School of Natural Sciences and Health, Tallinn University, Narva Road 29, 10120, Tallinn, Estonia
| | - Kairi Kasearu
- Institute of Social Studies, Faculty of Social Sciences, University of Tartu, Lossi 36, 51003, Tartu, Estonia
| | - Urmeli Katus
- Institute of Family Medicine and Public Health, Faculty of Medicine, University of Tartu, Ravila 19, 50411, Tartu, Estonia
| | - Toomas Veidebaum
- Department of Chronic Diseases, National Institute for Health Development, Hiiu 42, 11619, Tallinn, Estonia
| | - Jaanus Harro
- School of Natural Sciences and Health, Tallinn University, Narva Road 29, 10120, Tallinn, Estonia. .,Chair of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia.
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11
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Liu Y, Jiang H, Qin X, Tian M, Zhang H. PET imaging of reactive astrocytes in neurological disorders. Eur J Nucl Med Mol Imaging 2021; 49:1275-1287. [PMID: 34873637 PMCID: PMC8921128 DOI: 10.1007/s00259-021-05640-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/24/2021] [Indexed: 12/17/2022]
Abstract
The reactive astrocytes manifest molecular, structural, and functional remodeling in injury, infection, or diseases of the CNS, which play a critical role in the pathological mechanism of neurological diseases. A growing need exists for dependable approach to better characterize the activation of astrocyte in vivo. As an advanced molecular imaging technology, positron emission tomography (PET) has the potential for visualizing biological activities at the cellular levels. In the review, we summarized the PET visualization strategies for reactive astrocytes and discussed the applications of astrocyte PET imaging in neurological diseases. Future studies are needed to pay more attention to the development of specific imaging agents for astrocytes and further improve our exploration of reactive astrocytes in various diseases.
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Affiliation(s)
- Yu Liu
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, Zhejiang, China.,Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Han Jiang
- PET-CT Center, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Xiyi Qin
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, Zhejiang, China.,Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China
| | - Mei Tian
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, Zhejiang, China. .,Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, China. .,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China.
| | - Hong Zhang
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, Zhejiang, China. .,Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, China. .,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, China. .,College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China. .,Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China.
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12
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Abstract
We have structure, a wealth of kinetic data, thousands of chemical ligands and clinical information for the effects of a range of drugs on monoamine oxidase activity in vivo. We have comparative information from various species and mutations on kinetics and effects of inhibition. Nevertheless, there are what seem like simple questions still to be answered. This article presents a brief summary of existing experimental evidence the background and poses questions that remain intriguing for chemists and biochemists researching the chemical enzymology of and drug design for monoamine oxidases (FAD-containing EC 4.1.3.4).
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13
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Maltsev DV, Spasov AA, Miroshnikov MV, Skripka MO. Current Approaches to the Search of Anxiolytic Drugs. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2021. [DOI: 10.1134/s1068162021030122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Ni R, Röjdner J, Voytenko L, Dyrks T, Thiele A, Marutle A, Nordberg A. In vitro Characterization of the Regional Binding Distribution of Amyloid PET Tracer Florbetaben and the Glia Tracers Deprenyl and PK11195 in Autopsy Alzheimer's Brain Tissue. J Alzheimers Dis 2021; 80:1723-1737. [PMID: 33749648 PMCID: PMC8150513 DOI: 10.3233/jad-201344] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Emerging evidence indicates a central role of gliosis in Alzheimer's disease (AD) pathophysiology. However, the regional distribution and interaction of astrogliosis and microgliosis in association with amyloid-β (Aβ) still remain uncertain. OBJECTIVE Here we studied the pathological profiles in autopsy AD brain by using specific imaging tracers. METHODS Autopsy brain tissues of AD (n = 15, age 70.4±8.5 years) and control cases (n = 12, age 76.6±10.9) were examined with homogenate binding assays, autoradiography for Aβ plaques (3H-florbetaben/3H-PIB), astrogliosis (3H-L-deprenyl), and microgliosis (3H-PK11195/3H-FEMPA), as well as immunoassays. RESULTS In vitro saturation analysis revealed high-affinity binding sites of 3H-florbetaben, 3H-L-deprenyl, and 3H-PK11195/3H-FEMPA in the frontal cortex of AD cases. In vitro3H-florbetaben binding increased across cortical and subcortical regions of AD compared to control with the highest binding in the frontal and parietal cortices. The in vitro3H-L-deprenyl binding showed highest binding in the hippocampus (dentate gyrus) followed by cortical and subcortical regions of AD while the GFAP expression was upregulated only in the hippocampus compared to control. The in vitro3H-PK11195 binding was solely increased in the parietal cortex and the hippocampus of AD compared to control. The 3H-florbetaben binding positively correlated with the 3H-L-deprenyl binding in the hippocampus and parietal cortex of AD and controls. Similarly, a positive correlation was observed between 3H-florbetaben binding and GFAP expression in hippocampus of AD and control. CONCLUSION The use of multi-imaging tracers revealed different regional pattern of changes in autopsy AD brain with respect to amyloid plaque pathology versus astrogliosis and microgliosis.
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Affiliation(s)
- Ruiqing Ni
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Jennie Röjdner
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Larysa Voytenko
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | | | | | - Amelia Marutle
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Theme Aging, The Aging Brain Unit, Karolinska University Hospital, Stockholm, Sweden
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15
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Comprehensive review on design perspective of PET ligands based on β-amyloids, tau and neuroinflammation for diagnostic intervention of Alzheimer’s disease. Clin Transl Imaging 2021. [DOI: 10.1007/s40336-021-00410-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Thentu JB, Bhyrapuneni G, Padala NP, Chunduru P, Pantangi HR, Nirogi R. Evaluation of monoamine oxidase A and B type enzyme occupancy using non-radiolabelled tracers in rat brain. Neurochem Int 2021; 145:105006. [PMID: 33636211 DOI: 10.1016/j.neuint.2021.105006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 02/18/2021] [Accepted: 02/18/2021] [Indexed: 11/18/2022]
Abstract
Monoamine oxidase (MAO) enzymes, type A and B metabolise the amine neurotransmitters of the body. Selective inhibition of either enzyme is an approach for treating neurodegenerative and stress-induced disorders, and inhibition of an enzyme is proportional to the binding of the MAO inhibitor. Conventionally, the binding of test compounds to enzymes is assessed by radiolabelled ligands in ex vivo and in vivo occupancy assays. Regulatory restrictions and turnaround time are the limitations of the methods that use radiolabelled ligands. But the use of non-radiolabelled tracers and sensitive mass spectrometry (LC-MS/MS) based assays accelerated the determination of target occupancy in pre-clinical species. A report on use of non-radiolabelled ligand in in vivo MAO occupancy assay is not available. The objectives of the present study were to optimise non-radiolabelled harmine and deprenyl as selective tracers in MAO-A and MAO-B occupancy assays and evaluate MAO occupancy of test compounds in rat brain. Tracer optimisation resulted in a detectable, stable, and low ratio (<3.0) of tracer concentrations between any two brain tissues. In occupancy assay, tracer was intravenously administered (10 μg/kg, harmine or 60 μg/kg, L-deprenyl) after the treatment with test compound (clorgyline or tranylcypromine or pargyline or phenelzine or thioperamide). Specific brain tissues were isolated at a defined interval and tracer concentrations were quantified using LC-MS/MS method. Pre-treatment with MAO inhibitors resulted in a decrease (maximum, 80-85%) in harmine or an increase (maximum, 85-300%) in L-deprenyl concentrations. But we considered the change in tracer concentration, relative to the vehicle and positive control groups to calculate MAO occupancy. The observed selectivity and ratio of occupancies (ED50) of test compound towards MAO-A and MAO-B are comparable with the results from in vitro radiolabelled ligand-based inhibition assay. The results demonstrated the application of these non-radiolabelled tracers as suitable pre-clinical tools to determine MAO occupancy.
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Affiliation(s)
- Jagadeesh Babu Thentu
- Discovery Research, Suven Life Sciences Ltd, Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad, India.
| | - Gopinadh Bhyrapuneni
- Discovery Research, Suven Life Sciences Ltd, Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad, India.
| | - Nagasurya Prakash Padala
- Discovery Research, Suven Life Sciences Ltd, Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad, India.
| | - Prathyusha Chunduru
- Discovery Research, Suven Life Sciences Ltd, Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad, India.
| | - Hanumanth Rao Pantangi
- Discovery Research, Suven Life Sciences Ltd, Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad, India.
| | - Ramakrishna Nirogi
- Discovery Research, Suven Life Sciences Ltd, Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad, India.
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17
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Alluri SR, Kim SW, Volkow ND, Kil KE. PET Radiotracers for CNS-Adrenergic Receptors: Developments and Perspectives. Molecules 2020; 25:molecules25174017. [PMID: 32899124 PMCID: PMC7504810 DOI: 10.3390/molecules25174017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/29/2020] [Accepted: 09/01/2020] [Indexed: 12/30/2022] Open
Abstract
Epinephrine (E) and norepinephrine (NE) play diverse roles in our body’s physiology. In addition to their role in the peripheral nervous system (PNS), E/NE systems including their receptors are critical to the central nervous system (CNS) and to mental health. Various antipsychotics, antidepressants, and psychostimulants exert their influence partially through different subtypes of adrenergic receptors (ARs). Despite the potential of pharmacological applications and long history of research related to E/NE systems, research efforts to identify the roles of ARs in the human brain taking advantage of imaging have been limited by the lack of subtype specific ligands for ARs and brain penetrability issues. This review provides an overview of the development of positron emission tomography (PET) radiotracers for in vivo imaging of AR system in the brain.
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Affiliation(s)
- Santosh Reddy Alluri
- University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211-5110, USA;
| | - Sung Won Kim
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-1013, USA;
| | - Nora D. Volkow
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-1013, USA;
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892-1013, USA
- Correspondence: (N.D.V.); (K.-E.K.); Tel.: +1-(301)-443-6480 (N.D.V.); +1-(573)-884-7885 (K.-E.K.)
| | - Kun-Eek Kil
- University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211-5110, USA;
- Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211, USA
- Correspondence: (N.D.V.); (K.-E.K.); Tel.: +1-(301)-443-6480 (N.D.V.); +1-(573)-884-7885 (K.-E.K.)
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18
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Harada R, Hayakawa Y, Ezura M, Lerdsirisuk P, Du Y, Ishikawa Y, Iwata R, Shidahara M, Ishiki A, Kikuchi A, Arai H, Kudo Y, Yanai K, Furumoto S, Okamura N. 18F-SMBT-1: A Selective and Reversible PET Tracer for Monoamine Oxidase-B Imaging. J Nucl Med 2020; 62:253-258. [PMID: 32646880 DOI: 10.2967/jnumed.120.244400] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/15/2020] [Indexed: 11/16/2022] Open
Abstract
Reactive astrocytes play a key role in the pathogenesis of various neurodegenerative diseases. Monoamine oxidase-B (MAO-B) is one of the promising targets for the imaging of astrogliosis in the human brain. A novel selective and reversible MAO-B tracer, (S)-(2-methylpyrid-5-yl)-6-[(3-18F-fluoro-2-hydroxy)propoxy]quinoline (18F-SMBT-1), was successfully developed via lead optimization from the first-generation tau PET tracer 18F-THK-5351. Methods: SMBT-1 was radiolabeled with 18F using the corresponding precursor. The binding affinity of radiolabeled compounds to MAO-B was assessed using saturation and competitive binding assays. The binding selectivity of 18F-SMBT-1 to MAO-B was evaluated by autoradiography of frozen human brain tissues. The pharmacokinetics and metabolism were assessed in normal mice after intravenous administration of 18F-SMBT-1. A 14-d toxicity study after the intravenous administration of 18F-SMBT-1 was performed using rats and mice. Results: In vitro binding assays demonstrated a high binding affinity of 18F-SMBT-1 to MAO-B (dissociation constant, 3.7 nM). In contrast, it showed low binding affinity to MAO-A and protein aggregates such as amyloid-β and tau fibrils. Autoradiographic analysis showed higher amounts of 18F-SMBT-1 binding in the Alzheimer disease brain sections than in the control brain sections. 18F-SMBT-1 binding was completely displaced with the reversible MAO-B inhibitor lazabemide, demonstrating the high selectivity of 18F-SMBT-1 for MAO-B. Furthermore, 18F-SMBT-1 showed a high uptake by brain, rapid washout, and no radiolabeled metabolites in the brain of normal mice. 18F-SMBT-1 showed no significant binding to various receptors, ion channels, or transporters, and no toxic effects related to its administration were observed in mice and rats. Conclusion: 18F-SMBT-1 is a promising and selective MAO-B PET tracer candidate, which would be useful for quantitative monitoring of astrogliosis in the human brain.
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Affiliation(s)
- Ryuichi Harada
- Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan .,Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Yoshimi Hayakawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Michinori Ezura
- Department of Neurology, Tohoku University Graduate School of Medicine. 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | | | - Yiqing Du
- Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan
| | - Yoichi Ishikawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Ren Iwata
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Miho Shidahara
- Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Japan; and
| | - Aiko Ishiki
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Akio Kikuchi
- Department of Neurology, Tohoku University Graduate School of Medicine. 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Hiroyuki Arai
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Yukitsuka Kudo
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Kazuhiko Yanai
- Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan.,Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Nobuyuki Okamura
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan.,Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
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19
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Jurczak A, Szkup M, Safranow K, Samochowiec A, Wieder-Huszla S, Owsianowska J, Grochans E. The influence of genetic factors on personality and coping with stress among healthy late reproductive age women. Clin Interv Aging 2019; 14:1353-1360. [PMID: 31413556 PMCID: PMC6663037 DOI: 10.2147/cia.s211549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/21/2019] [Indexed: 11/23/2022] Open
Abstract
Background Psychological stress is a factor which predisposes people to many somatic and mental disorders. Women are at a significantly higher risk of stress than men, and their reactions to stress are stronger. Personality traits are thought to play a special role in the psychology of stress and may be crucial for the choice of a stress-coping strategy. Considering that stress is so common in everyday life, an attempt to understand how stress-coping styles are related to personality and genetic factors acquires special significance. Purpose The aim of this study was to analyze stress-coping styles and personality traits in healthy late reproductive age women with regard to genetic factors. Patients and methods The study involved 345 healthy late reproductive age women from northwest Poland, whose mean age was 42.3±4.5 years. The study was conducted using The Coping Inventory for Stressful Situations, The Neuroticism-Extraversion-Openness Five--Factor Inventory, and genetic testing. Results There were neither statistically significant relationships between personality traits and the genotype distribution of the 30-bp VNTR polymorphism in the MAO-A promoter region, nor between stress-coping styles and the genotype distribution of the 30-bp VNTR polymorphism in the MAO-A promoter region. Conclusion Based on the results, all personality traits statistically significantly correlated with the choice of task-oriented coping and emotion-oriented coping. Some of personality traits are genetically determined. The choice of a stress-coping style was significantly related to personality traits. A direct influence of genetic factors on the choice of a stress-coping style was not confirmed in our study.
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Affiliation(s)
- Anna Jurczak
- Department of Clinical Nursing, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Małgorzata Szkup
- Department of Nursing, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Krzysztof Safranow
- Department of Biochemistry, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Agnieszka Samochowiec
- Department of Clinical Psychology, Institute of Psychology, University of Szczecin, Szczecin, Poland
| | - Sylwia Wieder-Huszla
- Department of Clinical Nursing, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Joanna Owsianowska
- Department of Clinical Nursing, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Elżbieta Grochans
- Department of Nursing, Pomeranian Medical University in Szczecin, Szczecin, Poland
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20
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Yoshimoto M, Hirata M, Kagawa S, Magata Y, Ohmomo Y, Temma T. Synthesis and characterization of novel radiofluorinated probes for positron emission tomography imaging of monoamine oxidase B. J Labelled Comp Radiopharm 2019; 62:580-587. [DOI: 10.1002/jlcr.3779] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/18/2019] [Accepted: 06/11/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Mitsuyoshi Yoshimoto
- Department of Biofunctional Analysis; Osaka University of Pharmaceutical Sciences; Takatsuki Japan
- Division of Functional Imaging, Exploratory Oncology Research & Clinical Trial Center; National Cancer Center; Kashiwa Japan
| | - Masahiko Hirata
- Department of Biofunctional Analysis; Osaka University of Pharmaceutical Sciences; Takatsuki Japan
| | - Shinya Kagawa
- Department of Biofunctional Analysis; Osaka University of Pharmaceutical Sciences; Takatsuki Japan
- Division of PET Imaging; Shiga Medical Center Research Institute; Moriyama Japan
| | - Yasuhiro Magata
- Department of Nuclear Medicine and Diagnostic Imaging, Graduate School of Medicine; Kyoto University; Kyoto Japan
- Department of Molecular Imaging, Institute for Medical Photonics Research, Preeminent Medial Photonics Education and Research Center; Hamamatsu University School of Medicine; Hamamatsu Japan
| | - Yoshiro Ohmomo
- Department of Biofunctional Analysis; Osaka University of Pharmaceutical Sciences; Takatsuki Japan
| | - Takashi Temma
- Department of Biofunctional Analysis; Osaka University of Pharmaceutical Sciences; Takatsuki Japan
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21
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Dahl K, Bernard-Gauthier V, Nag S, Varnäs K, Narayanaswami V, Mahdi Moein M, Arakawa R, Vasdev N, Halldin C. Synthesis and preclinical evaluation of [18F]FSL25.1188, a reversible PET radioligand for monoamine oxidase-B. Bioorg Med Chem Lett 2019; 29:1624-1627. [DOI: 10.1016/j.bmcl.2019.04.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 10/26/2022]
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22
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Marais L, Petzer A, Petzer JP, Legoabe LJ. The monoamine oxidase inhibition properties of C6- and N1-substituted 3-methyl-3,4-dihydroquinazolin-2(1H)-one derivatives. Mol Divers 2019; 24:391-406. [PMID: 31115748 DOI: 10.1007/s11030-019-09960-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/15/2019] [Indexed: 12/30/2022]
Abstract
Quinazolinone compounds are of interest in medicinal chemistry since they display a wide range of biological properties. In the present study, a series of C6- and N1-substituted 3-methyl-3,4-dihydroquinazolin-2(1H)-one derivatives were synthesised and evaluated as inhibitors of recombinant human monoamine oxidase (MAO). Some of these quinazolinones are structurally related to a series of 3,4-dihydro-2(1H)-quinolinone derivatives, which have previously been reported to act as specific inhibitors of MAO-B. The results document that, among 37 compounds synthesised, seven displayed IC50 values < 1 µM for the inhibition of MAO-B. The most potent MAO-A inhibitor exhibits an IC50 value of 7.43 µM while the most potent MAO-B inhibitor possesses an IC50 value of 0.269 µM. Good-potency MAO inhibition was only observed among C6-substituted 3-methyl-3,4-dihydroquinazolin-2(1H)-one derivatives with N1-substitution yielding comparatively low-potency inhibition. MAO-B-specific inhibitors such as some of the quinazolinone compounds investigated here may act as leads for the design of therapies for neurodegenerative disorders such as Parkinson's disease.
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Affiliation(s)
- Lereze Marais
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - Anél Petzer
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.,Pharmaceutical Chemistry, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - Jacobus P Petzer
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.,Pharmaceutical Chemistry, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - Lesetja J Legoabe
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
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23
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Narayanaswami V, Drake LR, Brooks AF, Meyer JH, Houle S, Kilbourn MR, Scott PJH, Vasdev N. Classics in Neuroimaging: Development of PET Tracers for Imaging Monoamine Oxidases. ACS Chem Neurosci 2019; 10:1867-1871. [PMID: 30789704 DOI: 10.1021/acschemneuro.9b00081] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In this Viewpoint, we highlight the history of positron emission tomography (PET) radiotracer development to quantify changes in monoamine oxidase (MAO)-A and -B enzyme expression or activity. MAO-A and MAO-B are critical for understanding monoaminergic pathways in psychiatric addiction disorders, and more recently in neurodegenerative disorders with MAO-B expression in astrogliosis. Unique radiochemical innovations have been shown for neuroimaging of MAOs including the clinical translation of irreversible propargylamine-based suicide inhibitors, application of deuterium-substitution to slow down metabolism, development of trapped metabolite imaging agents, and unique 11C-carbonylation chemistry toward novel high-affinity reversibly binding inhibitors.
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Affiliation(s)
- Vidya Narayanaswami
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario M5T-1R8, Canada
| | - Lindsey R. Drake
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
- The Interdepartmental Program in Medicinal Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Allen F. Brooks
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Jeffrey H. Meyer
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario M5T-1R8, Canada
| | - Sylvain Houle
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario M5T-1R8, Canada
| | - Michael R. Kilbourn
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Peter J. H. Scott
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
- The Interdepartmental Program in Medicinal Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Neil Vasdev
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario M5T-1R8, Canada
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24
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Gendron T, Sander K, Cybulska K, Benhamou L, Sin PKB, Khan A, Wood M, Porter MJ, Årstad E. Ring-Closing Synthesis of Dibenzothiophene Sulfonium Salts and Their Use as Leaving Groups for Aromatic 18F-Fluorination. J Am Chem Soc 2018; 140:11125-11132. [PMID: 30132661 PMCID: PMC6128620 DOI: 10.1021/jacs.8b06730] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Indexed: 01/18/2023]
Abstract
Herein, we report a novel intramolecular ring-closing reaction of biaryl thioethers that give access to highly functionalized dibenzothiophene sulfonium salts under mild conditions. The resulting precursors react regioselectively with [18F]fluoride to give [18F]fluoroarenes in predictable radiochemical yields. The strategy expands the available radiochemical space and provides superior labeling efficiency for clinically relevant PET tracers.
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Affiliation(s)
- Thibault Gendron
- Institute
of Nuclear Medicine, University College
London, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Kerstin Sander
- Institute
of Nuclear Medicine, University College
London, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Klaudia Cybulska
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Laure Benhamou
- Institute
of Nuclear Medicine, University College
London, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Pak Kwan Brian Sin
- Institute
of Nuclear Medicine, University College
London, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Aqsa Khan
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Michael Wood
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Michael J. Porter
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Erik Årstad
- Institute
of Nuclear Medicine, University College
London, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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25
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Ishiki A, Harada R, Kai H, Sato N, Totsune T, Tomita N, Watanuki S, Hiraoka K, Ishikawa Y, Funaki Y, Iwata R, Furumoto S, Tashiro M, Sasano H, Kitamoto T, Kudo Y, Yanai K, Furukawa K, Okamura N, Arai H. Neuroimaging-pathological correlations of [ 18F]THK5351 PET in progressive supranuclear palsy. Acta Neuropathol Commun 2018; 6:53. [PMID: 29958546 PMCID: PMC6025736 DOI: 10.1186/s40478-018-0556-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 06/19/2018] [Indexed: 11/10/2022] Open
Abstract
Recent positron emission tomography (PET) studies have demonstrated the accumulation of tau PET tracer in the affected region of progressive supranuclear palsy (PSP) cases. To confirm the binding target of radiotracer in PSP, we performed an imaging-pathology correlation study in two autopsy-confirmed PSP patients who underwent [18F]THK5351 PET before death. One patient with PSP Richardson syndrome showed elevated tracer retention in the globus pallidus and midbrain. In a patient with PSP-progressive nonfluent aphasia, [18F]THK5351 retention also was observed in the cortical areas, particularly the temporal cortex. Neuropathological examination confirmed PSP in both patients. Regional [18F]THK5351 standardized uptake value ratio (SUVR) in antemortem PET was significantly correlated with monoamine oxidase-B (MAO-B) level, reactive astrocytes density, and tau pathology at postmortem examination. In in vitro autoradiography, specific THK5351 binding was detected in the area of antemortem [18F]THK5351 retention, and binding was blocked completely by a reversible selective MAO-B inhibitor, lazabemide, in brain samples from these patients. In conclusion, [18F]THK5351 PET signals reflect MAO-B expressing reactive astrocytes, which may be associated with tau accumulation in PSP.
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27
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Zirbesegger K, Buccino P, Kreimerman I, Engler H, Porcal W, Savio E. An efficient preparation of labelling precursor of [11C]L-deprenyl-D2 and automated radiosynthesis. EJNMMI Radiopharm Chem 2017; 2:10. [PMID: 29503851 PMCID: PMC5824701 DOI: 10.1186/s41181-017-0029-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/14/2017] [Indexed: 11/30/2022] Open
Abstract
Background The synthesis of [11C]L-deprenyl-D2 for imaging of astrocytosis with positron emission tomography (PET) in neurodegenerative diseases has been previously reported. [11C]L-deprenyl-D2 radiosynthesis requires a precursor, L-nordeprenyl-D2, which has been previously synthesized from L-amphetamine as starting material with low overall yields. Here, we present an efficient synthesis of L-nordeprenyl-D2 organic precursor as free base and automated radiosynthesis of [11C]L-deprenyl-D2 for PET imaging of astrocytosis. The L-nordeprenyl-D2 precursor was synthesized from the easily commercial available and cheap reagent L-phenylalanine in five steps. Next, N-alkylation of L-nordeprenyl-D2 free base with [11C]MeOTf was optimized using the automated commercial platform GE TRACERlab® FX C Pro. Results A simple and efficient synthesis of L-nordeprenyl-D2 precursor of [11C]L-deprenyl-D2 as free base has been developed in five synthetic steps with an overall yield of 33%. The precursor as free base has been stable for 9 months stored at low temperature (−20 °C). The labelled product was obtained with 44 ± 13% (n = 12) (end of synthesis, decay corrected) radiochemical yield from [11C]MeI after 35 min synthesis time. The radiochemical purity was over 99% in all cases and specific activity was (170 ± 116) GBq/μmol. Conclusions A high-yield synthesis of [11C]L-deprenyl-D2 has been achieved with high purity and specific activity. L-nordeprenyl-D2 precursor as free amine was applicable for automated production in a commercial synthesis module for preclinical and clinical application.
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Ramsay RR, Tipton KF. Assessment of Enzyme Inhibition: A Review with Examples from the Development of Monoamine Oxidase and Cholinesterase Inhibitory Drugs. Molecules 2017; 22:E1192. [PMID: 28714881 PMCID: PMC6152246 DOI: 10.3390/molecules22071192] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 11/16/2022] Open
Abstract
The actions of many drugs involve enzyme inhibition. This is exemplified by the inhibitors of monoamine oxidases (MAO) and the cholinsterases (ChE) that have been used for several pharmacological purposes. This review describes key principles and approaches for the reliable determination of enzyme activities and inhibition as well as some of the methods that are in current use for such studies with these two enzymes. Their applicability and potential pitfalls arising from their inappropriate use are discussed. Since inhibitor potency is frequently assessed in terms of the quantity necessary to give 50% inhibition (the IC50 value), the relationships between this and the mode of inhibition is also considered, in terms of the misleading information that it may provide. Incorporation of more than one functionality into the same molecule to give a multi-target-directed ligands (MTDLs) requires careful assessment to ensure that the specific target effects are not significantly altered and that the kinetic behavior remains as favourable with the MTDL as it does with the individual components. Such factors will be considered in terms of recently developed MTDLs that combine MAO and ChE inhibitory functions.
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Affiliation(s)
- Rona R Ramsay
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 8QP, UK.
| | - Keith F Tipton
- School of Biochemistry and Immunology, Trinity College, Dublin 2, Ireland.
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29
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Liang X, Duttwyler S. Efficient Brønsted-Acid-Catalyzed Deuteration of Arenes and Their Transformation to Functionalized Deuterated Products. ASIAN J ORG CHEM 2017. [DOI: 10.1002/ajoc.201700218] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Xuewei Liang
- Department of Chemistry; Zhejiang University; 38 Zheda Road 310027 Hangzhou P.R. China
| | - Simon Duttwyler
- Department of Chemistry; Zhejiang University; 38 Zheda Road 310027 Hangzhou P.R. China
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30
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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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31
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Zinc in the Monoaminergic Theory of Depression: Its Relationship to Neural Plasticity. Neural Plast 2017; 2017:3682752. [PMID: 28299207 PMCID: PMC5337390 DOI: 10.1155/2017/3682752] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/24/2017] [Indexed: 12/21/2022] Open
Abstract
Preclinical and clinical studies have demonstrated that zinc possesses antidepressant properties and that it may augment the therapy with conventional, that is, monoamine-based, antidepressants. In this review we aim to discuss the role of zinc in the pathophysiology and treatment of depression with regard to the monoamine hypothesis of the disease. Particular attention will be paid to the recently described zinc-sensing GPR39 receptor as well as aspects of zinc deficiency. Furthermore, an attempt will be made to give a possible explanation of the mechanisms by which zinc interacts with the monoamine system in the context of depression and neural plasticity.
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32
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Volkow ND, Wiers CE, Shokri-Kojori E, Tomasi D, Wang GJ, Baler R. Neurochemical and metabolic effects of acute and chronic alcohol in the human brain: Studies with positron emission tomography. Neuropharmacology 2017; 122:175-188. [PMID: 28108358 DOI: 10.1016/j.neuropharm.2017.01.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/20/2016] [Accepted: 01/14/2017] [Indexed: 02/07/2023]
Abstract
The use of Positron emission tomography (PET) to study the effects of acute and chronic alcohol on the human brain has enhanced our understanding of the mechanisms underlying alcohol's rewarding effects, the neuroadaptations from chronic exposure that contribute to tolerance and withdrawal, and the changes in fronto-striatal circuits that lead to loss of control and enhanced motivation to drink that characterize alcohol use disorders (AUD). These include studies showing that alcohol's reinforcing effects may result not only from its enhancement of dopaminergic, GABAergic and opioid signaling but also from its caloric properties. Studies in those suffering from an AUD have revealed significant alterations in dopamine (DA), GABA, cannabinoids, opioid and serotonin neurotransmission and in brain energy utilization (glucose and acetate metabolism) that are likely to contribute to compulsive alcohol taking, dysphoria/depression, and to alcohol-associated neurotoxicity. Studies have also evaluated the effects of abstinence on recovery of brain metabolism and neurotransmitter function and the potential value of some of these measures to predict clinical outcomes. Finally, PET studies have started to provide insights about the neuronal mechanisms by which certain genes contribute to the vulnerability to AUD. These findings have helped identify new strategies for prevention and treatment of AUD. This article is part of the Special Issue entitled "Alcoholism".
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Affiliation(s)
- Nora D Volkow
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States; National Institute on Alcohol Abuse and Alcoholism, Laboratory of Neuroimaging, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Corinde E Wiers
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Ehsan Shokri-Kojori
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Dardo Tomasi
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Gene-Jack Wang
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Ruben Baler
- National Institute on Alcohol Abuse and Alcoholism, Laboratory of Neuroimaging, National Institutes of Health, Bethesda, MD 20892, United States
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33
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Ramsay RR, Majekova M, Medina M, Valoti M. Key Targets for Multi-Target Ligands Designed to Combat Neurodegeneration. Front Neurosci 2016; 10:375. [PMID: 27597816 PMCID: PMC4992697 DOI: 10.3389/fnins.2016.00375] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 08/02/2016] [Indexed: 12/13/2022] Open
Abstract
HIGHLIGHTS Compounds that interact with multiple targets but minimally with the cytochrome P450 system (CYP) address the many factors leading to neurodegeneration.Acetyl- and Butyryl-cholineEsterases (AChE, BChE) and Monoamine Oxidases A/B (MAO A, MAO B) are targets for Multi-Target Designed Ligands (MTDL).ASS234 is an irreversible inhibitor of MAO A >MAO B and has micromolar potency against the cholinesterases.ASS234 is a poor CYP substrate in human liver, yielding the depropargylated metabolite.SMe1EC2, a stobadine derivative, showed high radical scavenging property, in vitro and in vivo giving protection in head trauma and diabetic damage of endothelium.Control of mitochondrial function and morphology by manipulating fission and fusion is emerging as a target area for therapeutic strategies to decrease the pathological outcome of neurodegenerative diseases. Growing evidence supports the view that neurodegenerative diseases have multiple and common mechanisms in their aetiologies. These multifactorial aspects have changed the broadly common assumption that selective drugs are superior to "dirty drugs" for use in therapy. This drives the research in studies of novel compounds that might have multiple action mechanisms. In neurodegeneration, loss of neuronal signaling is a major cause of the symptoms, so preservation of neurotransmitters by inhibiting the breakdown enzymes is a first approach. Acetylcholinesterase (AChE) inhibitors are the drugs preferentially used in AD and that one of these, rivastigmine, is licensed also for PD. Several studies have shown that monoamine oxidase (MAO) B, located mainly in glial cells, increases with age and is elevated in Alzheimer (AD) and Parkinson's Disease's (PD). Deprenyl, a MAO B inhibitor, significantly delays the initiation of levodopa treatment in PD patients. These indications underline that AChE and MAO are considered a necessary part of multi-target designed ligands (MTDL). However, both of these targets are simply symptomatic treatment so if new drugs are to prevent degeneration rather than compensate for loss of neurotransmitters, then oxidative stress and mitochondrial events must also be targeted. MAO inhibitors can protect neurons from apoptosis by mechanisms unrelated to enzyme inhibition. Understanding the involvement of MAO and other proteins in the induction and regulation of the apoptosis in mitochondria will aid progress toward strategies to prevent the loss of neurons. In general, the oxidative stress observed both in PD and AD indicate that antioxidant properties are a desirable part of MTDL molecules. After two or more properties are incorporated into one molecule, the passage from a lead compound to a therapeutic tool is strictly linked to its pharmacokinetic and toxicity. In this context the interaction of any new molecules with cytochrome P450 and other xenobiotic metabolic processes is a crucial point. The present review covers the biochemistry of enzymes targeted in the design of drugs against neurodegeneration and the cytochrome P450-dependent metabolism of MTDLs.
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Affiliation(s)
- Rona R. Ramsay
- Biomedical Sciences Research Complex, University of St. AndrewsSt. Andrews, UK
| | - Magdalena Majekova
- Department of Biochemical Pharmacology, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of SciencesBratislava, Slovakia
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias and BIFI, Universidad de ZaragozaZaragoza, Spain
| | - Massimo Valoti
- Dipartimento di Scienze della Vita, Università degli Studi di SienaSiena, Italy
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34
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Ramsay RR. Molecular aspects of monoamine oxidase B. Prog Neuropsychopharmacol Biol Psychiatry 2016; 69:81-9. [PMID: 26891670 DOI: 10.1016/j.pnpbp.2016.02.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/06/2016] [Accepted: 02/11/2016] [Indexed: 02/07/2023]
Abstract
Monoamine oxidases (MAO) influence the monoamine levels in brain by virtue of their role in neurotransmitter breakdown. MAO B is the predominant form in glial cells and in platelets. MAO B structure, function and kinetics are described as a background for the effect of alterations in its activity on behavior. The need to inhibit MAO B to combat decreased brain amines continues to drive the search for new drugs. Reversible and irreversible inhibitors are now designed using data-mining, computational screening, docking and molecular dynamics. Multi-target ligands designed to combat the elevated activity of MAO B in Alzheimer's and Parkinson's Diseases incorporate MAO inhibition (usually irreversible) as well as iron chelation, antioxidant or neuroprotective properties. The main focus of drug design is the catalytic activity of MAO, but the imidazoline I2 site in the entrance cavity of MAO B is also a pharmacological target. Endogenous regulation of MAO B expression is discussed briefly in light of new studies measuring mRNA, protein, or activity in healthy and degenerative samples, including the effect of DNA methylation on the expression. Overall, this review focuses on examples of recent research on the molecular aspects of the expression, activity, and inhibition of MAO B.
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Affiliation(s)
- Rona R Ramsay
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, United Kingdom.
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35
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Harro J, Oreland L. The role of MAO in personality and drug use. Prog Neuropsychopharmacol Biol Psychiatry 2016; 69:101-11. [PMID: 26964906 DOI: 10.1016/j.pnpbp.2016.02.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/16/2016] [Accepted: 02/17/2016] [Indexed: 02/04/2023]
Abstract
Monoamine oxidases, both MAO-A and MAO-B, have been implicated in personality traits and complex behaviour, including drug use. Findings supporting the involvement of MAO-A and MAO-B in shaping personality and in the development of strategies of making behavioural choices come from a variety of studies that have examined either prevalence of gene variants in clinical groups or population-derived samples, estimates of enzyme activity in blood or, by positron emission tomography, in the brain and, most recently, measurement of methylation of the gene. Most of the studies converge in associating MAO-A and MAO-B with impulsive, aggressive or antisocial personality traits or behaviours, including alcohol-related problems, and for MAO-A available evidence strongly supports interaction with adverse environmental exposures in childhood. What is known about genotype effects, and on expression and activity of the enzyme in the brain and in blood has not yet been possible to unite into a mechanistic model of the role of monoamine systems, but the reason for this low degree of generalization is likely caused by the cross-sectional nature of investigation that has not incorporated the developmental effects of MAO-s in critical time windows, including the foetal period. The "risk variants" of both MAO-s appear to increase behavioural plasticity, as supportive environments may particularly well enhance the hidden potential of their carriers. Importantly, male and female brain and behaviours have been found very different with regard to MAO×life events interaction. Future studies need to take into consideration these developmental aspects and sex/gender, as well as to specify the role of different types of environmental factors.
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Affiliation(s)
- Jaanus Harro
- Division of Neuropsychopharmacology, Department of Psychology, Estonian Centre of Behavioural and Health Sciences, University of Tartu, Estonia; Psychiatry Clinic, North Estonia Medical Centre, Tallinn, Estonia.
| | - Lars Oreland
- Department of Neuroscience, Pharmacology, University of Uppsala, Biomedical Centre, Uppsala, Sweden
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36
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Nikolac Perkovic M, Svob Strac D, Nedic Erjavec G, Uzun S, Podobnik J, Kozumplik O, Vlatkovic S, Pivac N. Monoamine oxidase and agitation in psychiatric patients. Prog Neuropsychopharmacol Biol Psychiatry 2016; 69:131-46. [PMID: 26851573 DOI: 10.1016/j.pnpbp.2016.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/15/2016] [Accepted: 02/02/2016] [Indexed: 11/17/2022]
Abstract
Subjects with schizophrenia or conduct disorder display a lifelong pattern of antisocial, aggressive and violent behavior and agitation. Monoamine oxidase (MAO) is an enzyme involved in the degradation of various monoamine neurotransmitters and neuromodulators and therefore has a role in various psychiatric and neurodegenerative disorders and pathological behaviors. Platelet MAO-B activity has been associated with psychopathy- and aggression-related personality traits, while variants of the MAOA and MAOB genes have been associated with diverse clinical phenotypes, including aggressiveness, antisocial problems and violent delinquency. The aim of the study was to evaluate the association of platelet MAO-B activity, MAOB rs1799836 polymorphism and MAOA uVNTR polymorphism with severe agitation in 363 subjects with schizophrenia and conduct disorder. The results demonstrated significant association of severe agitation and smoking, but not diagnosis or age, with platelet MAO-B activity. Higher platelet MAO-B activity was found in subjects with severe agitation compared to non-agitated subjects. Platelet MAO-B activity was not associated with MAOB rs1799836 polymorphism. These results suggested the association between increased platelet MAO-B activity and severe agitation. No significant association was found between severe agitation and MAOA uVNTR or MAOB rs1799836 polymorphism, revealing that these individual polymorphisms in MAO genes are not related to severe agitation in subjects with schizophrenia and conduct disorder. As our study included 363 homogenous Caucasian male subjects, our data showing this negative genetic association will be a useful addition to future meta-analyses.
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Affiliation(s)
- Matea Nikolac Perkovic
- Rudjer Boskovic Institute, Division of Molecular Medicine, Bijenicka cesta 54, 10000 Zagreb, Croatia
| | - Dubravka Svob Strac
- Rudjer Boskovic Institute, Division of Molecular Medicine, Bijenicka cesta 54, 10000 Zagreb, Croatia
| | - Gordana Nedic Erjavec
- Rudjer Boskovic Institute, Division of Molecular Medicine, Bijenicka cesta 54, 10000 Zagreb, Croatia
| | - Suzana Uzun
- Clinic for Psychiatry Vrapce, Bolnicka cesta 32, 10000 Zagreb, Croatia
| | - Josip Podobnik
- Department of Psychiatry, Psychiatric Hospital for Children and Youth Zagreb, Kukuljeviceva 11, 10000 Zagreb, Croatia
| | - Oliver Kozumplik
- Clinic for Psychiatry Vrapce, Bolnicka cesta 32, 10000 Zagreb, Croatia
| | | | - Nela Pivac
- Rudjer Boskovic Institute, Division of Molecular Medicine, Bijenicka cesta 54, 10000 Zagreb, Croatia.
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37
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Buccino P, Kreimerman I, Zirbesegger K, Porcal W, Savio E, Engler H. Automated radiosynthesis of [ 11 C]L-deprenyl-D 2 and [ 11 C]D-deprenyl using a commercial platform. Appl Radiat Isot 2016; 110:47-52. [DOI: 10.1016/j.apradiso.2015.12.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/24/2015] [Accepted: 12/20/2015] [Indexed: 10/22/2022]
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38
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Declercq LD, Vandenberghe R, Van Laere K, Verbruggen A, Bormans G. Drug Development in Alzheimer's Disease: The Contribution of PET and SPECT. Front Pharmacol 2016; 7:88. [PMID: 27065872 PMCID: PMC4814730 DOI: 10.3389/fphar.2016.00088] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/16/2016] [Indexed: 12/13/2022] Open
Abstract
Clinical trials aiming to develop disease-altering drugs for Alzheimer’s disease (AD), a neurodegenerative disorder with devastating consequences, are failing at an alarming rate. Poorly defined inclusion-and outcome criteria, due to a limited amount of objective biomarkers, is one of the major concerns. Non-invasive molecular imaging techniques, positron emission tomography and single photon emission (computed) tomography (PET and SPE(C)T), allow visualization and quantification of a wide variety of (patho)physiological processes and allow early (differential) diagnosis in many disorders. PET and SPECT have the ability to provide biomarkers that permit spatial assessment of pathophysiological molecular changes and therefore objectively evaluate and follow up therapeutic response, especially in the brain. A number of specific PET/SPECT biomarkers used in support of emerging clinical therapies in AD are discussed in this review.
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Affiliation(s)
- Lieven D Declercq
- Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven Leuven, Belgium
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven Leuven, Belgium
| | - Alfons Verbruggen
- Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven Leuven, Belgium
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Brooks AF, Shao X, Quesada CA, Sherman P, Scott PJH, Kilbourn MR. In Vivo Metabolic Trapping Radiotracers for Imaging Monoamine Oxidase-A and -B Enzymatic Activity. ACS Chem Neurosci 2015; 6:1965-71. [PMID: 26393369 DOI: 10.1021/acschemneuro.5b00223] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The isozymes of monoamine oxidase (MAO-A and MAO-B) are important enzymes involved in the metabolism of numerous biogenic amines, including the neurotransmitters serotonin, dopamine, and norepinephrine. Recently, changes in concentrations of MAO-B have been proposed to be an in vivo marker of neuroinflammation associated with Alzheimer's disease. Previous developments of in vivo radiotracers for imaging changes in MAO enzyme expression or activity have utilized the irreversible propargylamine-based suicide inhibitors or high-affinity reversibly binding inhibitors. As an alternative approach, we have investigated 1-[(11)C]methyl-4-aryloxy-1,2,3,6-tetrahydropyridines as metabolic trapping agents for the monoamine oxidases. MAO-mediated oxidation and spontaneous hydrolysis yield 1-[(11)C]methyl-2,3-dihydro-4-pyridinone as a hydrophilic metabolite that is trapped within brain tissues. Radiotracers with phenyl, biphenyl, and 7-coumarinyl ethers were evaluated using microPET imaging in rat and primate brains. No isozyme selectivity for radiotracer trapping was observed in the rat brain for any compound, but in the monkey brain, the phenyl ether demonstrated MAO-A selectivity and the coumarinyl ether showed MAO-B selectivity. These are lead compounds for further development of 1-[(11)C]methyl-4-aryloxy-1,2,3,6-tetrahydropyridines with optimized brain pharmacokinetics and isozyme selectivity.
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Affiliation(s)
- Allen F. Brooks
- Division of Nuclear Medicine, Department
of Radiology, ‡The Interdepartmental
Program in Medicinal Chemistry, University of Michigan Medical School, Ann
Arbor, Michigan 48109, United States
| | - Xia Shao
- Division of Nuclear Medicine, Department
of Radiology, ‡The Interdepartmental
Program in Medicinal Chemistry, University of Michigan Medical School, Ann
Arbor, Michigan 48109, United States
| | - Carole A. Quesada
- Division of Nuclear Medicine, Department
of Radiology, ‡The Interdepartmental
Program in Medicinal Chemistry, University of Michigan Medical School, Ann
Arbor, Michigan 48109, United States
| | - Phillip Sherman
- Division of Nuclear Medicine, Department
of Radiology, ‡The Interdepartmental
Program in Medicinal Chemistry, University of Michigan Medical School, Ann
Arbor, Michigan 48109, United States
| | - Peter J. H. Scott
- Division of Nuclear Medicine, Department
of Radiology, ‡The Interdepartmental
Program in Medicinal Chemistry, University of Michigan Medical School, Ann
Arbor, Michigan 48109, United States
| | - Michael R. Kilbourn
- Division of Nuclear Medicine, Department
of Radiology, ‡The Interdepartmental
Program in Medicinal Chemistry, University of Michigan Medical School, Ann
Arbor, Michigan 48109, United States
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40
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Janssen B, Vugts DJ, Funke U, Molenaar GT, Kruijer PS, van Berckel BNM, Lammertsma AA, Windhorst AD. Imaging of neuroinflammation in Alzheimer's disease, multiple sclerosis and stroke: Recent developments in positron emission tomography. Biochim Biophys Acta Mol Basis Dis 2015; 1862:425-41. [PMID: 26643549 DOI: 10.1016/j.bbadis.2015.11.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/13/2022]
Abstract
Neuroinflammation is thought to play a pivotal role in many diseases affecting the brain, including Alzheimer's disease, multiple sclerosis and stroke. Neuroinflammation is characterised predominantly by microglial activation, which can be visualised using positron emission tomography (PET). Traditionally, translocator protein 18kDa (TSPO) is the target for imaging of neuroinflammation using PET. In this review, recent preclinical and clinical research using PET in Alzheimer's disease, multiple sclerosis and stroke is summarised. In addition, new molecular targets for imaging of neuroinflammation, such as monoamine oxidases, adenosine receptors and cannabinoid receptor type 2, are discussed. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger.
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Affiliation(s)
- Bieneke Janssen
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
| | - Danielle J Vugts
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Uta Funke
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; BV Cyclotron VU, Amsterdam, The Netherlands
| | - Ger T Molenaar
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; BV Cyclotron VU, Amsterdam, The Netherlands
| | | | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
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Wiers CE, Cabrera E, Skarda E, Volkow ND, Wang GJ. PET imaging for addiction medicine: From neural mechanisms to clinical considerations. PROGRESS IN BRAIN RESEARCH 2015; 224:175-201. [PMID: 26822359 DOI: 10.1016/bs.pbr.2015.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Positron emission tomography (PET) has been shown to be an effective imaging technique to study neurometabolic and neurochemical processes involved in addiction. That is, PET has been used to research neurobiological differences in substance abusers versus healthy controls and the pharmacokinetics and pharmacodynamics of abused drugs. Over the past years, the research scope has shifted to investigating neurobiological effects of abstinence and treatment, and their predictive power for relapse and other clinical outcomes. This chapter provides an overview of PET methodology, recent human PET studies on drug addiction and their implications for clinical treatment.
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Affiliation(s)
- Corinde E Wiers
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
| | - Elizabeth Cabrera
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Emily Skarda
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Nora D Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA; National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA
| | - Gene-Jack Wang
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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42
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Maschauer S, Haller A, Riss PJ, Kuwert T, Prante O, Cumming P. Specific binding of [(18)F]fluoroethyl-harmol to monoamine oxidase A in rat brain cryostat sections, and compartmental analysis of binding in living brain. J Neurochem 2015; 135:908-17. [PMID: 26386360 DOI: 10.1111/jnc.13370] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 09/08/2015] [Accepted: 09/10/2015] [Indexed: 11/28/2022]
Abstract
We investigated [(18)F]fluoroethyl-harmol ([(18)F]FEH) as a reversible and selective ligand for positron emission tomography (PET) studies of monoamine oxidase A (MAO-A). Binding of [(18)F]FEH in rat brain cryostat sections indicated high affinity (KD = 3 nM), and density (Bmax; 600 pmol/g). The plasma free fraction was 45%, and untransformed parent constituted only 13% of plasma radioactivity at 10 min after injection. Compartmental analysis of PET recordings in pargyline-treated rats showed high permeability to brain (K1; 0.32 mL/g/min) and slow washout (k2; 0.024/min), resulting in a uniformly high equilibrium distribution volume (VD; 20 mL/g). Using this VD to estimate unbound ligand in brain of untreated rats, the binding potential ranged from 4.2 in cerebellum to 7.2 in thalamus. We also calculated maps of rats receiving [(18)F]FEH at a range of specific activities, and then estimated saturation binding parameters in the living brain. In thalamus, striatum and frontal cortex KD was globally close to 300 nM and Bmax was close to 1600 pmol/g; the 100-fold discrepancy in affinity suggests a very low free fraction for [(18)F]FEH in the living brain. Based on a synthesis of findings, we calculate the endogenous dopamine concentration to be 0.4 μM in the striatal compartment containing MAO-A, thus unlikely to exert competition against [(18)F]FEH binding in vivo. In summary, [(18)F]FEH has good properties for the detection of MAO-A in the rat brain by PET, and may present logistic advantages for clinical research at centers lacking a medical cyclotron. We made a compartmental analysis of [(18)F]fluoroethylharmol ([(18)F]FEH) binding to monoamine oxidase A (MAO-A) in living rat brain and estimated the saturation binding parameters from the binding potential (BPND). The Bmax was of comparable magnitude to that in vitro, but with apparent affinity (300 nM), it was 100-fold lower in vivo. PET imaging with [(18) F]FEH is well suited for quantitation of MAO-A in living brain.
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Affiliation(s)
- Simone Maschauer
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Adelina Haller
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Patrick J Riss
- Department of Chemistry, Universitetet i Oslo & Norsk Medisinisk Syklotronsenter AS, Oslo, Norway
| | - Torsten Kuwert
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Olaf Prante
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Paul Cumming
- Department of Neuroscience and Pharmacology, Copenhagen University, Copenhagen, Denmark.,Department of Neuropsychiatry and Psychosomatic Medicine, OUS-Rikshospitalet, Oslo, Norway
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