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Liao K, Chen JH, Ma J, Dong CC, Bi CY, Gao YB, Jiang YF, Wang T, Wei HY, Hou L, Hu JQ, Wei JJ, Zeng CY, Li YL, Yan S, Xu H, Liang SH, Wang L. Preclinical characterization of [ 18F]D 2-LW223: an improved metabolically stable PET tracer for imaging the translocator protein 18 kDa (TSPO) in neuroinflammatory rodent models and non-human primates. Acta Pharmacol Sin 2024:10.1038/s41401-024-01375-9. [PMID: 39210042 DOI: 10.1038/s41401-024-01375-9] [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: 05/19/2024] [Accepted: 07/31/2024] [Indexed: 09/04/2024] Open
Abstract
Positron emission tomography (PET) targeting translocator protein 18 kDa (TSPO) can be used for the noninvasive detection of neuroinflammation. Improved in vivo stability of a TSPO tracer is beneficial for minimizing the potential confounding effects of radiometabolites. Deuteration represents an important strategy for improving the pharmacokinetics and stability of existing drug molecules in the plasma. This study developed a novel tracer via the deuteration of [18F]LW223 and evaluated its in vivo stability and specific binding in neuroinflammatory rodent models and nonhuman primate (NHP) brains. Compared with LW223, D2-LW223 exhibited improved binding affinity to TSPO. Compared with [18F]LW223, [18F]D2-LW223 has superior physicochemical properties and favorable brain kinetics, with enhanced metabolic stability and reduced defluorination. Preclinical investigations in rodent models of LPS-induced neuroinflammation and cerebral ischemia revealed specific [18F]D2-LW223 binding to TSPO in regions affected by neuroinflammation. Two-tissue compartment model analyses provided excellent model fits and allowed the quantitative mapping of TSPO across the NHP brain. These results indicate that [18F]D2-LW223 holds significant promise for the precise quantification of TSPO expression in neuroinflammatory pathologies of the brain.
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Affiliation(s)
- Kai Liao
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jia-Hui Chen
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Jie Ma
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Chen-Chen Dong
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Chun-Yang Bi
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Ya-Biao Gao
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Yuan-Fang Jiang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Tao Wang
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, 510632, China
| | - Hui-Yi Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jun-Qi Hu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jun-Jie Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Chun-Yuan Zeng
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Yin-Long Li
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Sen Yan
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, 510632, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China.
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA.
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China.
- Guangzhou Key Laboratory of Basic and Translational Research on Chronic Disease, Guangzhou, 510630, China.
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2
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Sakai T, Hattori S, Ogata A, Yamada T, Abe J, Ikenuma H, Ichise M, Suzuki M, Ito K, Kato T, Kimura Y. Noradrenaline transporter PET reflects neurotoxin-induced noradrenaline level decrease in the rat hippocampus. EJNMMI Res 2023; 13:82. [PMID: 37713137 PMCID: PMC10504202 DOI: 10.1186/s13550-023-01032-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 09/08/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND The neuropathological changes of early Alzheimer's disease (AD) include neurodegenerative loss of noradrenaline neurons in the locus coeruleus with decreasing noradrenaline availability in their projection areas such as the hippocampus. This diminishing noradrenaline availability is thought to play an important role pathophysiologically in the development of cognitive impairment in AD, because noradrenaline is not only essential for maintaining cognitive functions such as memory, learning and attention, but also its anti-inflammatory action, where its lack is known to accelerate the progression of AD in the mouse model. Therefore, the availability of in vivo biomarkers of the integrity of noradrenaline neurons may be beneficial for furthering our understanding of the role played by the noradrenaline system in the progressive cognitive dysfunction seen in AD patients. In this study, we investigated if PET imaging of noradrenaline transporters can predict the level of noradrenaline in the brain. Our hypothesis was PET measured noradrenaline transporter densities could predict the level of noradrenaline concentrations in the rat hippocampus after lesioning of noradrenaline neurons in this region. RESULTS We chemically lesioned the hippocampus of rats (n = 15) by administering a neurotoxin, DSP-4, in order to selectively damage axonal terminals of noradrenergic neurons. These rats then underwent PET imaging of noradrenaline transporters using [11C]MRB ((S,S)-[11C]Methylreboxetine). To validate our hypothesis, postmortem studies of brain homogenates of these rats were performed to measure both noradrenaline transporter and noradrenaline concentrations. [11C]MRB PET showed decreased noradrenaline transporter densities in a DSP-4 dose-dependent manner in the hippocampus of these rats. In turn, these PET measured noradrenaline transporter densities correlated very well with in vitro measured noradrenaline concentrations as well as in vitro transporter densities. CONCLUSIONS [11C]MRB PET may be used as an in vivo biomarker of noradrenaline concentrations in the hippocampus of the neurodegenerating brain. Further studies appear warranted to extend its applicability to AD studies.
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Affiliation(s)
- Takayuki Sakai
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Saori Hattori
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Aya Ogata
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
- Department of Pharmacy, Faculty of Pharmacy, Gifu University of Medical Science (GUMS), Kani, Japan
| | - Takashi Yamada
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Junichiro Abe
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Hiroshi Ikenuma
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Masanori Ichise
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Masaaki Suzuki
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Kengo Ito
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Takashi Kato
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan
| | - Yasuyuki Kimura
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, Research Institute, National Center for Geriatrics and Gerontology (NCGG), Obu, Aichi, 474-8511, Japan.
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3
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Sun Y, Ramos-Torres KM, Brugarolas P. Metabolic Stability of the Demyelination Positron Emission Tomography Tracer [ 18F]3-Fluoro-4-Aminopyridine and Identification of Its Metabolites. J Pharmacol Exp Ther 2023; 386:93-101. [PMID: 37024145 PMCID: PMC10289238 DOI: 10.1124/jpet.122.001462] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 03/05/2023] [Accepted: 03/23/2023] [Indexed: 04/08/2023] Open
Abstract
[18F]3-fluoro-4-aminopyridine ([18F]3F4AP) is a positron emission tomography (PET) tracer for imaging demyelination based on the multiple sclerosis drug 4-aminopyridine (4AP, dalfampridine). This radiotracer was found to be stable in rodents and nonhuman primates imaged under isoflurane anesthesia. However, recent findings indicate that its stability is greatly decreased in awake humans and mice. Since both 4AP and isoflurane are metabolized primarily by cytochrome P450 enzymes, particularly cytochrome P450 family 2 subfamily E member 1 (CYP2E1), we postulated that this enzyme may be responsible for the metabolism of 3F4AP. Here, we investigated the metabolism of [18F]3F4AP by CYP2E1 and identified its metabolites. We also investigated whether deuteration, a common approach to increase the stability of drugs, could improve its stability. Our results demonstrate that CYP2E1 readily metabolizes 3F4AP and its deuterated analogs and that the primary metabolites are 5-hydroxy-3F4AP and 3F4AP N-oxide. Although deuteration did not decrease the rate of the CYP2E1-mediated oxidation, our findings explain the diminished in vivo stability of 3F4AP compared with 4AP and further our understanding of when deuteration may improve the metabolic stability of drugs and PET ligands. SIGNIFICANCE STATEMENT: The demyelination tracer [18F]3F4AP was found to undergo rapid metabolism in humans, which could compromise its utility. Understanding the enzymes and metabolic products involved may offer strategies to reduce metabolism. Using a combination of in vitro assays and chemical syntheses, this report shows that cytochrome P450 enzyme CYP2E1 is likely responsible for [18F]3F4AP metabolism, that 4-amino-5-fluoroprydin-3-ol (5-hydroxy-3F4AP, 5OH3F4AP) and 4-amino-3-fluoropyridine 1-oxide (3F4AP N-oxide) are the main metabolites, and that deuteration is unlikely to improve the stability of the tracer in vivo.
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Affiliation(s)
- Yang Sun
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Karla M Ramos-Torres
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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4
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Liu L, Johnson PD, Prime ME, Khetarpal V, Brown CJ, Anzillotti L, Bertoglio D, Chen X, Coe S, Davis R, Dickie AP, Esposito S, Gadouleau E, Giles PR, Greenaway C, Haber J, Halldin C, Haller S, Hayes S, Herbst T, Herrmann F, Heßmann M, Hsai MM, Khani Y, Kotey A, Lembo A, Mangette JE, Marriner GA, Marston RW, Mills MR, Monteagudo E, Forsberg-Morén A, Nag S, Orsatti L, Sandiego C, Schaertl S, Sproston J, Staelens S, Tookey J, Turner PA, Vecchi A, Veneziano M, Muñoz-Sanjuan I, Bard J, Dominguez C. Design and Evaluation of [ 18F]CHDI-650 as a Positron Emission Tomography Ligand to Image Mutant Huntingtin Aggregates. J Med Chem 2023; 66:641-656. [PMID: 36548390 DOI: 10.1021/acs.jmedchem.2c01585] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Therapeutic interventions are being developed for Huntington's disease (HD), a hallmark of which is mutant huntingtin protein (mHTT) aggregates. Following the advancement to human testing of two [11C]-PET ligands for aggregated mHTT, attributes for further optimization were identified. We replaced the pyridazinone ring of CHDI-180 with a pyrimidine ring and minimized off-target binding using brain homogenate derived from Alzheimer's disease patients. The major in vivo metabolic pathway via aldehyde oxidase was blocked with a 2-methyl group on the pyrimidine ring. A strategically placed ring-nitrogen on the benzoxazole core ensured high free fraction in the brain without introducing efflux. Replacing a methoxy pendant with a fluoro-ethoxy group and introducing deuterium atoms suppressed oxidative defluorination and accumulation of [18F]-signal in bones. The resulting PET ligand, CHDI-650, shows a rapid brain uptake and washout profile in non-human primates and is now being advanced to human testing.
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Affiliation(s)
- Longbin Liu
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
| | - Peter D Johnson
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Michael E Prime
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Vinod Khetarpal
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
| | - Christopher J Brown
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Luca Anzillotti
- Experimental Pharmacology Department, IRBM S.p.A., Via Pontina km 30,600, Pomezia, Roma 00071, Italy
| | - Daniele Bertoglio
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Xuemei Chen
- Curia Global, Inc., 1001 Main Street, Buffalo, New York 14203, United States
| | - Samuel Coe
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Randall Davis
- Curia Global, Inc., 1001 Main Street, Buffalo, New York 14203, United States
| | - Anthony P Dickie
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Simone Esposito
- Experimental Pharmacology Department, IRBM S.p.A., Via Pontina km 30,600, Pomezia, Roma 00071, Italy
| | - Elise Gadouleau
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Paul R Giles
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Catherine Greenaway
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - James Haber
- Curia Global, Inc., 1001 Main Street, Buffalo, New York 14203, United States
| | - Christer Halldin
- Department of Clinical Neuroscience, Centre for Psychiatric Research, Karolinska Hospital, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Scott Haller
- Charles River Laboratories, 54943 North Main Street, Mattawan, Michigan 49071, United States
| | - Sarah Hayes
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Todd Herbst
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
| | - Frank Herrmann
- Evotec SE, Manfred Eigen Campus, Essener Bogen 7, Hamburg 22419, Germany
| | - Manuela Heßmann
- Evotec SE, Manfred Eigen Campus, Essener Bogen 7, Hamburg 22419, Germany
| | - Ming Min Hsai
- Curia Global, Inc., 1001 Main Street, Buffalo, New York 14203, United States
| | - Yaser Khani
- Department of Clinical Neuroscience, Centre for Psychiatric Research, Karolinska Hospital, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Adrian Kotey
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Angelo Lembo
- Experimental Pharmacology Department, IRBM S.p.A., Via Pontina km 30,600, Pomezia, Roma 00071, Italy
| | - John E Mangette
- Curia Global, Inc., 1001 Main Street, Buffalo, New York 14203, United States
| | - Gwendolyn A Marriner
- Charles River Laboratories, 54943 North Main Street, Mattawan, Michigan 49071, United States
| | - Richard W Marston
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Matthew R Mills
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Edith Monteagudo
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
| | - Anton Forsberg-Morén
- Department of Clinical Neuroscience, Centre for Psychiatric Research, Karolinska Hospital, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Sangram Nag
- Department of Clinical Neuroscience, Centre for Psychiatric Research, Karolinska Hospital, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Laura Orsatti
- Experimental Pharmacology Department, IRBM S.p.A., Via Pontina km 30,600, Pomezia, Roma 00071, Italy
| | - Christine Sandiego
- Invicro, 60 Temple St, Ste 8A, New Haven, Connecticut 06510, United States
| | - Sabine Schaertl
- Evotec SE, Manfred Eigen Campus, Essener Bogen 7, Hamburg 22419, Germany
| | - Joanne Sproston
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Steven Staelens
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Jack Tookey
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Penelope A Turner
- Evotec (U.K.) Ltd, 114 Innovation Drive, Milton Park, Abingdon OX14 4RZ, U.K
| | - Andrea Vecchi
- Experimental Pharmacology Department, IRBM S.p.A., Via Pontina km 30,600, Pomezia, Roma 00071, Italy
| | - Maria Veneziano
- Experimental Pharmacology Department, IRBM S.p.A., Via Pontina km 30,600, Pomezia, Roma 00071, Italy
| | - Ignacio Muñoz-Sanjuan
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
| | - Jonathan Bard
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
| | - Celia Dominguez
- CHDI Management/CHDI Foundation, 6080 Center Drive, Suite 700, Los Angeles, California 90045, United States
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5
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Nag S, Jahan M, Tóth M, Nakao R, Varrone A, Halldin C. PET Imaging of VMAT2 with the Novel Radioligand [ 18F]FE-DTBZ-d4 in Nonhuman Primates: Comparison with [ 11C]DTBZ and [ 18F]FE-DTBZ. ACS Chem Neurosci 2021; 12:4580-4586. [PMID: 34813272 PMCID: PMC8678981 DOI: 10.1021/acschemneuro.1c00651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
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The vesicular monoamine
transporter type 2 (VMAT2) is believed
to be responsible for the uptake of monoamines into the vesicles of
the synaptic terminals. Two VMAT2 radioligands [11C]DTBZ
and [18F]FP-DTBZ have been used to assess the degree of
nigrostriatal deficit in Parkinson’s disease (PD) using positron
emission tomography (PET). [18F]FE-DTBZ-d4, the nondeuterated
analogue of [18F]FE-DTBZ showed similar imaging properties
with better stability against defluorination. Therefore, [18F]FE-DTBZ-d4 draws attention to be investigated as an imaging marker
for VMAT2 in the brain. The aim of this study was to investigate the
brain kinetics and quantification of [18F]FE-DTBZ-d4 in
nonhuman primates (NHPs), with comparison to [11C]DTBZ
and [18F]FE-DTBZ. Radiolabeling was successfully achieved
either by one-step 11C-methylation or by a two-step fluorine-18
nucleophilic substitution reaction. The stability and radiochemical
yield were analyzed with high-performance liquid chromatography (HPLC).
Three female cynomolgus monkeys were included in the study and underwent
a total of 12 positron emission tomography (PET) measurements. Each
monkey was examined with each tracer. In addition, two pretreatment
and one displacement PET measurements with tetrabenazine (2.0 mg/kg)
were performed for [18F]FE-DTBZ-d4. All PET measurements
were conducted using a high-resolution research tomograph (HRRT) system.
Radiometabolites were measured in monkey plasma using gradient radio-HPLC.
[18F]FE-DTBZ-d4 (SUV: 4.28 ± 1.01) displayed higher
brain uptake compared to both [18F]FE-DTBZ (SUV: 3.43 ±
0.54) and [11C]DTBZ (SUV: 3.06 ± 0.32) and faster
washout. Binding potential (BPND) values of [18F]FE-DTBZ-d4 in different brain regions (putamen: 5.5 ± 1.4;
caudate: 4.4 ± 1.1; midbrain: 1.4 ± 0.4) were higher than
those of [11C]DTBZ and [18F]FE-DTBZ. [18F]FE-DTBZ showed faster radiometabolism in plasma compared to [11C]DTBZ and [18F]FE-DTBZ-d4. [18F]FE-DTBZ-d4
is a suitable radioligand for quantification of VMAT2 in the nonhuman
primate brain, with better imaging properties than [11C]DTBZ
and [18F]FE-DTBZ. A preliminary comparison suggests that
[18F]FE-DTBZ-d4 has increased stability against defluorination
compared to the nondeuterated analogue.
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Affiliation(s)
- Sangram Nag
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Mahabuba Jahan
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Miklós Tóth
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Ryuji Nakao
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Andrea Varrone
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
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6
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Deng X, Salgado-Polo F, Shao T, Xiao Z, Van R, Chen J, Rong J, Haider A, Shao Y, Josephson L, Perrakis A, Liang SH. Imaging Autotaxin In Vivo with 18F-Labeled Positron Emission Tomography Ligands. J Med Chem 2021; 64:15053-15068. [PMID: 34662125 DOI: 10.1021/acs.jmedchem.1c00913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Autotaxin (ATX) is a secreted phosphodiesterase that has been implicated in a remarkably wide array of pathologies, especially in fibrosis and cancer. While ATX inhibitors have entered the clinical arena, a validated probe for positron emission tomography (PET) is currently lacking. With the aim to develop a suitable ATX-targeted PET radioligand, we have synthesized a focused library of fluorinated imidazo[1,2-a]pyridine derivatives, determined their inhibition constants, and confirmed their binding mode by crystallographic analysis. Based on their promising in vitro properties, compounds 9c, 9f, 9h, and 9j were radiofluorinated. Also, a deuterated analog of [18F]9j, designated as [18F]ATX-1905 ([18F]20), was designed and proved to be highly stable against in vivo radiodefluorination compared with [18F]9c, [18F]9f, [18F]9h, and [18F]9j. These results along with in vitro and in vivo studies toward ATX in a mouse model of LPS-induced liver injury suggest that [18F]ATX-1905 is a suitable PET probe for the non-invasive quantification of ATX.
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Affiliation(s)
- Xiaoyun Deng
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States.,Department of Nuclear Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Fernando Salgado-Polo
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Tuo Shao
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Zhiwei Xiao
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Richard Van
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Jiahui Chen
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Yihan Shao
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Anastassis Perrakis
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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7
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Lepron M, Daniel-Bertrand M, Mencia G, Chaudret B, Feuillastre S, Pieters G. Nanocatalyzed Hydrogen Isotope Exchange. Acc Chem Res 2021; 54:1465-1480. [PMID: 33622033 DOI: 10.1021/acs.accounts.0c00721] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Recently, hydrogen isotope exchange (HIE) reactions have experienced impressive development due to the growing importance of isotope containing compounds in various fields including materials and life sciences, in addition to their classical use for mechanistic studies in chemistry and biology. Tritium-labeled compounds are also of crucial interest to study the in vivo fate of a bioactive substance or in radioligand binding assays. Over the past few years, deuterium-labeled drugs have been extensively studied for the improvement of ADME (absorption, distribution, metabolism, excretion) properties of existing bioactive molecules as a consequence of the primary kinetic isotope effect. Furthermore, in the emergent "omic" fields, the need for new stable isotopically labeled internal standards (SILS) for quantitative GC- or LC-MS analyses is increasing. Because of their numerous applications, the development of powerful synthetic methods to access deuterated and tritiated molecules with either high isotope incorporation and/or selectivities is of paramount importance.HIE reactions allow a late-stage incorporation of hydrogen isotopes in a single synthetic step, thus representing an advantageous alternative to conventional multistep synthesis approaches which are time- and resource-consuming. Moreover, HIE reactions can be considered as the most fundamental C-H functionalization processes and are therefore of great interest for the chemists' community. Depending on the purpose, HIE reactions must either be highly regioselective or allow a maximal incorporation of hydrogen isotopes, sometimes both. In this context, metal-catalyzed HIE reactions are generally performed using either homogeneous or heterogeneous catalysis which may have considerable drawbacks including an insufficient isotope incorporation and a lack of chemo- and/or regioselectivity, respectively.Over the past 6 years, we have shown that nanocatalysis can be considered as a powerful tool to access complex labeled molecules (e.g., pharmaceuticals, peptides and oligonucleotides) via regio- and chemoselective or even enantiospecific labeling processes occurring at the surface of metallic nanoclusters (Ru or Ir). Numerous heterocyclic (both saturated and unsaturated) and acyclic scaffolds have been labeled with an impressive functional group tolerance, and highly deuterated compounds or high molar activity tritiated drugs have been obtained. An insight into mechanisms has also been provided by theoretical calculations to explain the regioselectivities of the isotope incorporation. Our studies have suggested that undisclosed key intermediates, including 4- and 5-membered dimetallacycles, account for the particular regioselectivities observed during the process, in contrast to the 5- or 6-membered metallacycle key intermediates usually encountered in homogeneous catalysis. These findings together with the important number of available coordination sites explain the compelling reactivity of metal nanoparticles, in between homogeneous and heterogeneous catalysis. They represent innovative tools combining the advantages of both methods for the isotopic labeling and activation of C-H bonds of complex molecules.
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Affiliation(s)
- Marco Lepron
- Département Médicaments et Technologies pour la Santé (DMTS), SCBM, Université Paris-Saclay, CEA, INRAE, Bat 547, 91191 Gif-sur-Yvette, France
| | - Marion Daniel-Bertrand
- Département Médicaments et Technologies pour la Santé (DMTS), SCBM, Université Paris-Saclay, CEA, INRAE, Bat 547, 91191 Gif-sur-Yvette, France
| | - Gabriel Mencia
- Institut National des Sciences Appliquées, LPCNO, Université de Toulouse, UMR 5215 INSA-CNRS-UPS, 135, Avenue de Rangueil, F-31077 Toulouse, France
| | - Bruno Chaudret
- Institut National des Sciences Appliquées, LPCNO, Université de Toulouse, UMR 5215 INSA-CNRS-UPS, 135, Avenue de Rangueil, F-31077 Toulouse, France
| | - Sophie Feuillastre
- Département Médicaments et Technologies pour la Santé (DMTS), SCBM, Université Paris-Saclay, CEA, INRAE, Bat 547, 91191 Gif-sur-Yvette, France
| | - Grégory Pieters
- Département Médicaments et Technologies pour la Santé (DMTS), SCBM, Université Paris-Saclay, CEA, INRAE, Bat 547, 91191 Gif-sur-Yvette, France
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8
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Ghosh KK, Padmanabhan P, Yang CT, Mishra S, Halldin C, Gulyás B. Dealing with PET radiometabolites. EJNMMI Res 2020; 10:109. [PMID: 32997213 PMCID: PMC7770856 DOI: 10.1186/s13550-020-00692-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/07/2020] [Indexed: 02/08/2023] Open
Abstract
Abstract Positron emission tomography (PET) offers the study of biochemical,
physiological, and pharmacological functions at a cellular and molecular level.
The performance of a PET study mostly depends on the used radiotracer of
interest. However, the development of a novel PET tracer is very difficult, as
it is required to fulfill a lot of important criteria. PET radiotracers usually
encounter different chemical modifications including redox reaction, hydrolysis,
decarboxylation, and various conjugation processes within living organisms. Due
to this biotransformation, different chemical entities are produced, and the
amount of the parent radiotracer is declined. Consequently, the signal measured
by the PET scanner indicates the entire amount of radioactivity deposited in the
tissue; however, it does not offer any indication about the chemical disposition
of the parent radiotracer itself. From a radiopharmaceutical perspective, it is
necessary to quantify the parent radiotracer’s fraction present in the tissue.
Hence, the identification of radiometabolites of the radiotracers is vital for
PET imaging. There are mainly two reasons for the chemical identification of PET
radiometabolites: firstly, to determine the amount of parent radiotracers in
plasma, and secondly, to rule out (if a radiometabolite enters the brain) or
correct any radiometabolite accumulation in peripheral tissue. Besides,
radiometabolite formations of the tracer might be of concern for the PET study,
as the radiometabolic products may display considerably contrasting distribution
patterns inside the body when compared with the radiotracer itself. Therefore,
necessary information is needed about these biochemical transformations to
understand the distribution of radioactivity throughout the body. Various
published review articles on PET radiometabolites mainly focus on the sample
preparation techniques and recently available technology to improve the
radiometabolite analysis process. This article essentially summarizes the
chemical and structural identity of the radiometabolites of various radiotracers
including [11C]PBB3,
[11C]flumazenil,
[18F]FEPE2I, [11C]PBR28,
[11C]MADAM, and
(+)[18F]flubatine. Besides, the importance of
radiometabolite analysis in PET imaging is also briefly summarized. Moreover,
this review also highlights how a slight chemical modification could reduce the
formation of radiometabolites, which could interfere with the results of PET
imaging. Graphical abstract ![]()
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Affiliation(s)
- Krishna Kanta Ghosh
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore.
| | - Chang-Tong Yang
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore.,Department of Nuclear Medicine and Molecular Imaging, Radiological Sciences Division, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore.,Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Sachin Mishra
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Christer Halldin
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore.,Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76, Stockholm, Sweden
| | - Balázs Gulyás
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore. .,Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76, Stockholm, Sweden.
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9
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Lahdenpohja S, Keller T, Forsback S, Viljanen T, Kokkomäki E, Kivelä RV, Bergman J, Solin O, Kirjavainen AK. Automated GMP production and long-term experience in radiosynthesis of CB 1 tracer [ 18 F]FMPEP-d 2. J Labelled Comp Radiopharm 2020; 63:408-418. [PMID: 32374481 DOI: 10.1002/jlcr.3845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/31/2020] [Accepted: 04/28/2020] [Indexed: 11/11/2022]
Abstract
Here, we describe the development of an in-house-built device for the fully automated multistep synthesis of the cannabinoid CB1 receptor imaging tracer (3R,5R)-5-(3-([18 F]fluoromethoxy-d2 )phenyl)-3-(((R)-1-phenylethyl)amino)-1-(4-(trifluoromethyl)phenyl)pyrrolidin-2-one ([18 F]FMPEP-d2 ), following good manufacturing practices. The device is interfaced to a HPLC and a sterile filtration unit in a clean room hot cell. The synthesis involves the nucleophilic 18 F-fluorination of an alkylating agent and its GC purification, the subsequent 18 F-fluoroalkylation of a precursor molecule, the semipreparative HPLC purification of the 18 F-fluoroalkylated product, and its formulation for injection. We have optimized the duration and temperature of the 18 F-fluoroalkylation reaction and addressed the radiochemical stability of the formulated product. During the past 5 years (2013-2018), we have performed a total of 149 syntheses for clinical use with a 90% success rate. The activity yield of the formulated product has been 1.0 ± 0.4 GBq starting from 11 ± 2 GBq and the molar activity 600 ± 300 GBq/μmol at the end of synthesis.
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Affiliation(s)
- Salla Lahdenpohja
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Thomas Keller
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Sarita Forsback
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
- Department of Chemistry, University of Turku, Turku, Finland
| | - Tapio Viljanen
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Esa Kokkomäki
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Riikka V Kivelä
- Hospital Pharmacy, Turku University Hospital, Turku, Finland
| | - Jörgen Bergman
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Olof Solin
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
- Department of Chemistry, University of Turku, Turku, Finland
- Accelerator Laboratory, Turku PET Centre, Åbo Akademi University, Turku, Finland
| | - Anna K Kirjavainen
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
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10
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Arakawa R, Takano A, Halldin C. PET technology for drug development in psychiatry. Neuropsychopharmacol Rep 2020; 40:114-121. [PMID: 32463584 PMCID: PMC7722687 DOI: 10.1002/npr2.12084] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/05/2019] [Accepted: 10/18/2019] [Indexed: 12/14/2022] Open
Abstract
Positron emission tomography (PET) is a non‐invasive imaging method to measure the molecule in vivo. PET imaging can evaluate the central nervous system drugs as target engagement in the human brain. For antipsychotic drugs, adequate dopamine D2 receptor occupancy (“therapeutic window”) is reported to be from 65%‐70% to 80% to achieve the antipsychotic effect without extrapyramidal symptoms. For antidepressants, the clinical threshold of serotonin transporter (5‐HTT) occupancy is reported to be 70%‐80% although the relation between the side effect and 5‐HTT occupancy has not yet been established. Evaluation of norepinephrine transporter (NET) occupancy for antidepressant is ongoing as adequate PET radioligands for NET were developed recently. Measurement of the target occupancy has been a key element to evaluate the in vivo target engagement of the drugs. In order to evaluate new drug targets for disease conditions such as negative symptoms/cognitive impairment of schizophrenia and treatment‐resistant depression, new PET radioligands need to be developed concurrently with the drug development. PET imaging can evaluate the central nervous system drugs as target engagement in the human brain. The uptake of [11C]raclopride for dopamine D2 receptors decreased from (A) baseline to (B) antipsychotic administration conditions.![]()
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Affiliation(s)
- Ryosuke Arakawa
- Center for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Akihiro Takano
- Center for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.,Takeda Development Center Japan, Takeda Pharmaceutical Company Limited, Osaka, Japan
| | - Christer Halldin
- Center for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
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11
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Recent advances in radiotracers targeting norepinephrine transporter: structural development and radiolabeling improvements. J Neural Transm (Vienna) 2020; 127:851-873. [PMID: 32274584 PMCID: PMC7223405 DOI: 10.1007/s00702-020-02180-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/21/2020] [Indexed: 12/13/2022]
Abstract
The norepinephrine transporter (NET) is a major target for the evaluation of the cardiac sympathetic nerve system in patients with heart failure and Parkinson's disease. It is also used in the therapeutic applications against certain types of neuroendocrine tumors, as exemplified by the clinically used 123/131I-MIBG as theranostic single-photon emission computed tomography (SPECT) agent. With the development of more advanced positron emission tomography (PET) technology, more radiotracers targeting NET have been reported, with superior temporal and spatial resolutions, along with the possibility of functional and kinetic analysis. More recently, fluorine-18-labelled NET tracers have drawn increasing attentions from researchers, due to their longer radiological half-life relative to carbon-11 (110 min vs. 20 min), reduced dependence on on-site cyclotrons, and flexibility in the design of novel tracer structures. In the heart, certain NET tracers provide integral diagnostic information on sympathetic innervation and the nerve status. In the central nervous system, such radiotracers can reveal NET distribution and density in pathological conditions. Most radiotracers targeting cardiac NET-function for the cardiac application consistent of derivatives of either norepinephrine or MIBG with its benzylguanidine core structure, e.g. 11C-HED and 18F-LMI1195. In contrast, all NET tracers used in central nervous system applications are derived from clinically used antidepressants. Lastly, possible applications of NET as selective tracers over organic cation transporters (OCTs) in the kidneys and other organs controlled by sympathetic nervous system will also be discussed.
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12
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Sanabria Bohórquez S, Marik J, Ogasawara A, Tinianow JN, Gill HS, Barret O, Tamagnan G, Alagille D, Ayalon G, Manser P, Bengtsson T, Ward M, Williams SP, Kerchner GA, Seibyl JP, Marek K, Weimer RM. [ 18F]GTP1 (Genentech Tau Probe 1), a radioligand for detecting neurofibrillary tangle tau pathology in Alzheimer's disease. Eur J Nucl Med Mol Imaging 2019; 46:2077-2089. [PMID: 31254035 DOI: 10.1007/s00259-019-04399-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 06/11/2019] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Neurofibrillary tangles (NFTs), consisting of intracellular aggregates of the tau protein, are a pathological hallmark of Alzheimer's disease (AD). Here we report the identification and initial characterization of Genentech Tau Probe 1 ([18F]GTP1), a small-molecule PET probe for imaging tau pathology in AD patients. METHODS Autoradiography using human brain tissues from AD donors and protein binding panels were used to determine [18F]GTP1 binding characteristics. Stability was evaluated in vitro and in vivo in mice and rhesus monkey. In the clinic, whole-body imaging was performed to assess biodistribution and dosimetry. Dynamic [18F]GTP1 brain imaging and input function measurement were performed on two separate days in 5 β-amyloid plaque positive (Aβ+) AD and 5 β-amyloid plaque negative (Aβ-) cognitive normal (CN) participants. Tracer kinetic modeling was applied and reproducibility was evaluated. SUVR was calculated and compared to [18F]GTP1-specific binding parameters derived from the kinetic modeling. [18F]GTP1 performance in a larger cross-sectional group of 60 Aβ+ AD participants and ten (Aβ- or Aβ+) CN was evaluated with images acquired 60 to 90 min post tracer administration. RESULTS [18F]GTP1 exhibited high affinity and selectivity for tau pathology with no measurable binding to β-amyloid plaques or MAO-B in AD tissues, or binding to other tested proteins at an affinity predicted to impede image data interpretation. In human, [18F]GTP1 exhibited favorable dosimetry and brain kinetics, and no evidence of defluorination. [18F]GTP1-specific binding was observed in cortical regions of the brain predicted to contain tau pathology in AD and exhibited low (< 4%) test-retest variability. SUVR measured in the 60 to 90-min interval post injection correlated with tracer-specific binding (slope = 1.36, r2 = 0.98). Furthermore, in a cross-sectional population, the degree of [18F]GTP1-specific binding increased with AD severity and could differentiate diagnostic cohorts. CONCLUSIONS [18F]GTP1 is a promising PET probe for the study of tau pathology in AD.
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Affiliation(s)
| | - Jan Marik
- Department of Biomedical Imaging, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Annie Ogasawara
- Department of Biomedical Imaging, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Jeff N Tinianow
- Department of Biomedical Imaging, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Herman S Gill
- Department of Biomedical Imaging, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Olivier Barret
- Invicro LLC, 60 Temple St, Suite 8A, New Haven, CT, 06510, USA
| | - Gilles Tamagnan
- Invicro LLC, 60 Temple St, Suite 8A, New Haven, CT, 06510, USA
- XingImaging, LLC, 760 Chapel Street, New Haven, CT, 06510, USA
| | - David Alagille
- Invicro LLC, 60 Temple St, Suite 8A, New Haven, CT, 06510, USA
- XingImaging, LLC, 760 Chapel Street, New Haven, CT, 06510, USA
| | - Gai Ayalon
- Department of Neuroscience, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Paul Manser
- Clinical Biostatistics, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Thomas Bengtsson
- Clinical Biostatistics, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Michael Ward
- Early Clinical Development, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
- Alector, Inc., 151 Oyster Point Blvd, South San Francisco, CA, 94080, USA
| | - Simon-Peter Williams
- Department of Biomedical Imaging, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Geoffrey A Kerchner
- Early Clinical Development, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - John P Seibyl
- Invicro LLC, 60 Temple St, Suite 8A, New Haven, CT, 06510, USA
| | - Kenneth Marek
- Invicro LLC, 60 Temple St, Suite 8A, New Haven, CT, 06510, USA
| | - Robby M Weimer
- Department of Biomedical Imaging, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA.
- Department of Neuroscience, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA.
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13
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Deng X, Rong J, Wang L, Vasdev N, Zhang L, Josephson L, Liang SH. Chemistry for Positron Emission Tomography: Recent Advances in 11 C-, 18 F-, 13 N-, and 15 O-Labeling Reactions. Angew Chem Int Ed Engl 2019; 58:2580-2605. [PMID: 30054961 PMCID: PMC6405341 DOI: 10.1002/anie.201805501] [Citation(s) in RCA: 207] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Indexed: 01/07/2023]
Abstract
Positron emission tomography (PET) is a molecular imaging technology that provides quantitative information about function and metabolism in biological processes in vivo for disease diagnosis and therapy assessment. The broad application and rapid advances of PET has led to an increased demand for new radiochemical methods to synthesize highly specific molecules bearing positron-emitting radionuclides. This Review provides an overview of commonly used labeling reactions through examples of clinically relevant PET tracers and highlights the most recent developments and breakthroughs over the past decade, with a focus on 11 C, 18 F, 13 N, and 15 O.
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Affiliation(s)
- Xiaoyun Deng
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Lu Wang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Lei Zhang
- Medicine Design, Pfizer Inc., Cambridge, MA, 02139, USA
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
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14
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Deng X, Rong J, Wang L, Vasdev N, Zhang L, Josephson L, Liang SH. Chemie der Positronenemissionstomographie: Aktuelle Fortschritte bei
11
C‐,
18
F‐,
13
N‐ und
15
O‐Markierungsreaktionen. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201805501] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Xiaoyun Deng
- Division of Nuclear Medicine and Molecular ImagingMassachusetts General Hospital & Department of RadiologyHarvard Medical School Boston MA 02114 USA
| | - Jian Rong
- Division of Nuclear Medicine and Molecular ImagingMassachusetts General Hospital & Department of RadiologyHarvard Medical School Boston MA 02114 USA
| | - Lu Wang
- Division of Nuclear Medicine and Molecular ImagingMassachusetts General Hospital & Department of RadiologyHarvard Medical School Boston MA 02114 USA
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular ImagingMassachusetts General Hospital & Department of RadiologyHarvard Medical School Boston MA 02114 USA
| | - Lei Zhang
- Medicine DesignPfizer Inc. Cambridge MA 02139 USA
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular ImagingMassachusetts General Hospital & Department of RadiologyHarvard Medical School Boston MA 02114 USA
| | - Steven H. Liang
- Division of Nuclear Medicine and Molecular ImagingMassachusetts General Hospital & Department of RadiologyHarvard Medical School Boston MA 02114 USA
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15
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Arakawa R, Stenkrona P, Takano A, Svensson J, Andersson M, Nag S, Asami Y, Hirano Y, Halldin C, Lundberg J. Venlafaxine ER Blocks the Norepinephrine Transporter in the Brain of Patients with Major Depressive Disorder: a PET Study Using [18F]FMeNER-D2. Int J Neuropsychopharmacol 2019; 22:278-285. [PMID: 30649319 PMCID: PMC6441126 DOI: 10.1093/ijnp/pyz003] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/21/2018] [Accepted: 01/09/2019] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The in vivo binding of clinical dose of venlafaxine on norepinephrine transporter has been questioned because venlafaxine has higher in vitro affinity to serotonin transporter than that to norepinephrine transporter. Although serotonin transporter occupancy of clinically relevant doses of venlafaxine has been reported, there has been no report of norepinephrine transporter occupancy in the human brain. METHODS This was an open-label, single center, exploratory positron emission tomography study. Twelve major depressive disorder patients who had responded to venlafaxine extended-release and 9 control subjects were recruited. Each subject participated in one positron emission tomography measurement with [18F]FMeNER-D2. Binding potential in brain was quantified by the area under the curve ratio method with thalamus as target and white matter as reference regions. The difference of binding potential values between control and patient groups divided to 2 dose ranges were evaluated. Norepinephrine transporter occupancy (%) for all the major depressive disorder patients was calculated using mean binding potential of control subjects as baseline. The relationships between dose or plasma concentration of total active moiety and occupancies of norepinephrine transporter were also estimated. RESULTS The binding potential of the patient group with 150 to 300 mg/d was significantly lower than that in the control subjects group (P = .0004 < .05/2). The norepinephrine transporter occupancy (8-61%) increased in a dose-dependent manner although a clear difference beyond 150 mg/d was not observed. CONCLUSIONS This study demonstrates that clinically relevant doses of venlafaxine extended-release block the norepinephrine transporter of the major depressive disorder patient's brain. The data support the notion that the antidepressant effect of venlafaxine involves a combination of serotonin transporter and norepinephrine transporter blockades.
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Affiliation(s)
- Ryosuke Arakawa
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden,Correspondence: Ryosuke Arakawa, MD, PhD, Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden. Post address: Karolinska University Hospital Solna, R5:02, SE-17176 Stockholm, Sweden ()
| | - Per Stenkrona
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Akihiro Takano
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Jonas Svensson
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Max Andersson
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Sangram Nag
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Yuko Asami
- Central Nervous System, Medical Affairs, Pfizer Essential Health, Pfizer Japan Inc., Tokyo, Japan
| | - Yoko Hirano
- Central Nervous System, Medical Affairs, Pfizer Essential Health, Pfizer Japan Inc., Tokyo, Japan
| | - Christer Halldin
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Johan Lundberg
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
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16
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López-Picón FR, Kirjavainen AK, Forsback S, Takkinen JS, Peters D, Haaparanta-Solin M, Solin O. In vivo characterization of a novel norepinephrine transporter PET tracer [ 18F]NS12137 in adult and immature Sprague-Dawley rats. Am J Cancer Res 2019; 9:11-19. [PMID: 30662550 PMCID: PMC6332804 DOI: 10.7150/thno.29740] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/16/2018] [Indexed: 12/31/2022] Open
Abstract
Norepinephrine modulates cognitive processes such as working and episodic memory. Pathological changes in norepinephrine and norepinephrine transporter (NET) function and degeneration of the locus coeruleus produce irreversible impairments within the whole norepinephrine system, disrupting cognitive processes. Monitoring these changes could enhance diagnostic accuracy and support development of novel therapeutic components for several neurodegenerative diseases. Thus, we aimed to develop a straightforward nucleophilic fluorination method with high molar activity for the novel NET radiotracer [18F]NS12137 and to demonstrate the ability of [18F]NS12137 to quantify changes in NET expression. Methods: We applied an 18F-radiolabeling method in which a brominated precursor was debrominated by nucleophilic 18F-fluorination in dimethyl sulfoxide. Radiolabeling was followed by a deprotection step, purification, and formulation of the radiotracer. The [18F]NS12137 brain uptake and distribution were studied with in vivo PET/CT and ex vivo autoradiography using both adult and immature Sprague-Dawley rats because postnatal NET expression peaks at 10-20 days post birth. The NET specificity for the tracer was demonstrated by pretreatment of the animals with nisoxetine, which is well-known to have a high affinity for NET. Results: [18F]NS12137 was successfully synthesized with radiochemical yields of 18.6±5.6%, radiochemical purity of >99%, and molar activity of >500 GBq/μmol at the end of synthesis. The in vivo [18F]NS12137 uptake showed peak standard uptake values (SUV) of over 1.5 (adult) and 2.2 (immature) in the different brain regions. Peak SUV/30 min and peak SUV/60 min ratios were calculated for the different brain regions of the adult and immature rats, with a peak SUV/60 min ratio of more than 4.5 in the striatum of adult rats. As expected, in vivo studies demonstrated uptake of the tracer in brain areas rich in NET, particularly thalamus, neocortex, and striatum, and remarkably also in the locus coeruleus, a quite small volume for imaging with PET. The uptake was significantly higher in immature rats compared to the adult animals. Ex vivo studies using autoradiography showed very strong specific binding in NET-rich areas such as the locus coeruleus and the bed nucleus of the stria terminalis, and high binding in larger grey matter areas such as the neocortex and striatum. The uptake of [18F]NS12137 was dramatically reduced both in vivo and ex vivo by pretreatment with nisoxetine, demonstrating the specificity of binding. Conclusions: [18F]NS12137 was synthesized in good yield and high molar activity and demonstrated the characteristics of a good radiotracer, such as good brain penetration, fast washout, and high specific binding to NET.
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Shrestha S, Singh P, Cortes-Salva MY, Jenko KJ, Ikawa M, Kim MJ, Kobayashi M, Morse CL, Gladding RL, Liow JS, Zoghbi SS, Fujita M, Innis RB, Pike VW. 3-Substituted 1,5-Diaryl-1 H-1,2,4-triazoles as Prospective PET Radioligands for Imaging Brain COX-1 in Monkey. Part 2: Selection and Evaluation of [ 11C]PS13 for Quantitative Imaging. ACS Chem Neurosci 2018; 9:2620-2627. [PMID: 29792035 DOI: 10.1021/acschemneuro.8b00103] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In our preceding paper (Part 1), we identified three 1,5-bis-diaryl-1,2,4-triazole-based compounds that merited evaluation as potential positron emission tomography (PET) radioligands for selectively imaging cyclooxygenase-1 (COX-1) in monkey and human brain, namely, 1,5-bis(4-methoxyphenyl)-3-(alkoxy)-1 H-1,2,4-triazoles bearing a 3-methoxy (PS1), a 3-(2,2,2-trifluoroethoxy) (PS13), or a 3-fluoromethoxy substituent (PS2). PS1 and PS13 were labeled from phenol precursors by O-11C-methylation with [11C]iodomethane and PS2 by O-18F-fluoroalkylation with [2H2,18F]fluorobromomethane. Here, we evaluated these PET radioligands in monkey. All three radioligands gave moderately high uptake in brain, although [2H2,18F]PS2 also showed undesirable radioactivity uptake in skull. [11C]PS13 was selected for further evaluation, mainly based on more favorable brain kinetics than [11C]PS1. Pharmacological preblock experiments showed that about 55% of the radioactivity uptake in brain was specifically bound to COX-1. An index of enzyme density, VT, was well identified from serial brain scans and from the concentrations of parent radioligand in arterial plasma. In addition, VT values were stable within 80 min, suggesting that brain uptake was not contaminated by radiometabolites. [11C]PS13 successfully images and quantifies COX-1 in monkey brain, and merits further investigation for imaging COX-1 in monkey models of neuroinflammation and in healthy human subjects.
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Affiliation(s)
- Stal Shrestha
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Prachi Singh
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Michelle Y. Cortes-Salva
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Kimberly J. Jenko
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Masamichi Ikawa
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Min-Jeong Kim
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Masato Kobayashi
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Cheryl L. Morse
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Robert L. Gladding
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Sami S. Zoghbi
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Robert B. Innis
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Victor W. Pike
- Molecular Imaging Branch, National Institute
of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
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Arakawa R, Takano A, Halldin C. Serotonin and Norepinephrine Transporter Occupancy of Tramadol in Nonhuman Primate Using Positron Emission Tomography. Int J Neuropsychopharmacol 2018; 22:53-56. [PMID: 30346535 PMCID: PMC6313119 DOI: 10.1093/ijnp/pyy089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 10/17/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Tramadol, a centrally acting analgesic drug, has relatively high affinity to serotonin transporter and norepinephrine transporter in addition to μ-opioid receptor. Based on this characteristic, tramadol is expected to have an antidepressant effect. METHODS Positron emission tomography measurements with [11C]MADAM and [18F]FMeNER-D2 were performed at baseline and after i.v. administration of 3 different doses (1, 2, and 4 mg/kg) of tramadol using 6 cynomolgus monkeys. The relationship between dose and occupancy for serotonin transporter and norepinephrine transporter was estimated. RESULTS Tramadol occupied similarly both serotonin transporter (40%-72%) and norepinephrine transporter (7%-73%) in a dose-dependent manner. The Kd was 2.2 mg/kg and 2.0 mg/kg for serotonin transporter and norepinephrine transporter, respectively. CONCLUSIONS Both serotonin transporter and norepinephrine transporter of in vivo brain were blocked at >70% at a clinically relevant high dose of tramadol. This study suggests tramadol has potential antidepressant effects through the inhibition of serotonin transporter and norepinephrine transporter in the brain.
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Affiliation(s)
- Ryosuke Arakawa
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden,Correspondence: Ryosuke Arakawa, MD, PhD, Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden, Karolinska University Hospital, R5:02, SE-17176 Stockholm, Sweden ()
| | - Akihiro Takano
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
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Preclinical comparison study between [ 18F]fluoromethyl-PBR28 and its deuterated analog in a rat model of neuroinflammation. Bioorg Med Chem Lett 2018; 28:2925-2929. [PMID: 30122224 DOI: 10.1016/j.bmcl.2018.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/30/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Abstract
We designed and synthesized deuterium-substituted [18F]fluoromethyl-PBR28 ([18F]1-d2) as a novel translocator protein 18 kDa (TSPO)-targeted radioligand with enhanced in vivo stability. The comparison studies between [18F]fluoromethyl-PBR28 ([18F]1) and its deuterate analog ([18F]1-d2) were investigated in terms of in vitro binding affinity, lipophilicity and in vivo stability. In addition, the accuracies of both radioligands were determined by comparing the PET imaging data in the same LPS-induced neuroinflammation rat model. Both aryloxyanilide analogs showed similar lipophilicity and in vitro affinity for TSPO. However, [18F]1-d2 provided significantly lower femur uptake than [18F]1 (1.5 ± 1.2 vs. 4.1 ± 1.7%ID/g at 2 h post-injection) in an ex vivo biodistribution study. [18F]1-d2 was also selectively accumulated in the inflammatory lesion with the binding potential of the specifically bound radioligand relative to the non-displaceable radioligand in tissue (BPND = 3.17 ± 0.48), in a LPS-induced acute neuroinflammation rat model, comparable to that of [18F]1 (BPND = 2.13 ± 0.51). These results indicate that [18F]1-d2 had higher in vivo stability, which resulted in an enhanced target-to-background ratio compared to that induced by [18F]1.
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20
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Kirjavainen AK, Forsback S, López-Picón FR, Marjamäki P, Takkinen J, Haaparanta-Solin M, Peters D, Solin O. 18F-labeled norepinephrine transporter tracer [ 18F]NS12137: radiosynthesis and preclinical evaluation. Nucl Med Biol 2017; 56:39-46. [PMID: 29172120 DOI: 10.1016/j.nucmedbio.2017.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 10/11/2017] [Accepted: 10/16/2017] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Several psychiatric and neurodegenerative diseases are associated with malfunction of brain norepinephrine transporter (NET). However, current clinical evaluations of NET function are limited by the lack of sufficiently sensitive methods of detection. To this end, we have synthesized exo-3-[(6-[18F]fluoro-2-pyridyl)oxy]-8-azabicyclo[3.2.1]-octane ([18F]NS12137) as a radiotracer for positron emission tomography (PET) and have demonstrated that it is highly specific for in vivo detection of NET-rich regions of rat brain tissue. METHODS We applied two methods of electrophilic, aromatic radiofluorination of the precursor molecule, exo-3-[(6-trimethylstannyl-2-pyridyl)oxy]-8-azabicyclo-[3.2.1]octane-8-carboxylate: (1) direct labeling with [18F]F2, and (2) labeling with [18F]Selectfluor, a derivative of [18F]F2, using post-target produced [18F]F2. The time-dependent distribution of [18F]NS12137 in brain tissue of healthy, adult Sprague-Dawley rats was determined by ex vivo autoradiography. The specificity of [18F]NS12137 binding was demonstrated on the basis of competitive binding by nisoxetine, a known NET antagonist of high specificity. RESULTS [18F]NS12137 was successfully synthesized with radiochemical yields of 3.9% ± 0.3% when labeled with [18F]F2 and 10.2% ± 2.7% when labeled with [18F]Selectfluor. The molar activity of radiotracer was 8.8 ± 0.7 GBq/μmol with [18F]F2 labeling and 6.9 ± 0.4 GBq/μmol with [18F]Selectfluor labeling at the end of synthesis of [18F]NS12137. Uptake of [18F]NS12137 in NET-rich areas in rat brain was demonstrated with the locus coeruleus (LCoe) having the highest regional uptake. Prior treatment of rats with nisoxetine showed no detectable [18F]NS12137 in the LCoe. Analyses of whole brain samples for radiometabolites showed only the parent compound [18F]NS12137. Uptake of 18F-radioactivity in bone increased with time. CONCLUSIONS The two electrophilic 18F-labeling methods proved to be suitable for synthesis of [18F]NS12137 with the [18F]Selectfluor method providing an approximate three-fold higher yield than the [18F]F2 method. As an electrostatically neutral radiotracer [18F]NS12137 crosses the blood-brain barrier and enabled specific labeling of NET-rich regions of rat brain tissue with the highest concentration in the LCoe.
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Affiliation(s)
- Anna K Kirjavainen
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.
| | - Sarita Forsback
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland
| | - Francisco R López-Picón
- Preclinical Imaging, Turku PET Centre, University of Turku, Turku, Finland; Medicity Research Laboratory, University of Turku, Turku, Finland
| | | | - Jatta Takkinen
- Preclinical Imaging, Turku PET Centre, University of Turku, Turku, Finland; Medicity Research Laboratory, University of Turku, Turku, Finland
| | - Merja Haaparanta-Solin
- Preclinical Imaging, Turku PET Centre, University of Turku, Turku, Finland; Medicity Research Laboratory, University of Turku, Turku, Finland
| | - Dan Peters
- DanPET AB, Malmö, Sweden; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Olof Solin
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland; Accelerator Laboratory, Åbo Akademi University, Turku, Finland
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21
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Development of two fluorine-18 labeled PET radioligands targeting PDE10A and in vivo PET evaluation in nonhuman primates. Nucl Med Biol 2017; 57:12-19. [PMID: 29223715 DOI: 10.1016/j.nucmedbio.2017.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/02/2017] [Accepted: 10/20/2017] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Phosphodiesterase 10A (PDE10A) is a member of the PDE enzyme family that degrades cyclic adenosine and guanosine monophosphates (cAMP and cGMP). Based on the successful development of [11C]T-773 as PDE10A positron emission tomography (PET) radioligand, in this study our aim was to develop and evaluate fluorine-18 analogs of [11C]T-773. METHODS [18F]FM-T-773-d2 and [18F]FE-T-773-d4 were synthesized from the same precursor used for 11C-labeling of T-773 in a two-step approach via 18F-fluoromethylation and 18F-fluoroethylation, respectively, using corresponding deuterated synthons. A total of 12 PET measurements were performed in seven non-human primates. First, baseline PET measurements were performed using High Resolution Research Tomograph system with both [18F]FM-T-773-d2 and [18F]FE-T-773-d4; the uptake in whole brain and separate brain regions, as well as the specific binding and tissue ratio between putamen and cerebellum, was examined. Second, baseline and pretreatment PET measurements using MP-10 as the blocker were performed for [18F]FM-T-773-d2 including arterial blood sampling with radiometabolite analysis in four NHPs. RESULTS Both [18F]FM-T-773-d2 and [18F]FE-T-773-d4 were successfully radiolabeled with an average molar activity of 293 ± 114 GBq/μmol (n=8) for [18F]FM-T-773-d2 and 209 ± 26 GBq/μmol (n=4) for [18F]FE-T-773-d4, and a radiochemical yield of 10% (EOB, n=12, range 3%-16%). Both radioligands displayed high brain uptake (~5.5% of injected radioactivity for [18F]FM-T-773-d2 and ~3.5% for [18F]FE-T-773-d4 at the peak) and a fast washout. Specific binding reached maximum within 30 min for [18F]FM-T-773-d2 and after approximately 45 min for [18F]FE-T-773-d4. [18F]FM-T-773-d2 data fitted well with kinetic compartment models. BPND values obtained indirectly through compartment models were correlated well with those obtained by SRTM. BPND calculated with SRTM was 1.0-1.7 in the putamen. The occupancy with 1.8 mg/kg of MP-10 was approximately 60%. CONCLUSIONS [18F]FM-T-773-d2 and [18F]FE-T-773-d4 were developed as fluorine-18 PET radioligands for PDE10A, with the [18F]FM-T-773-d2 being the more promising PET radioligand warranting further evaluation.
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Shahzad D, Faisal M, Rauf A, Huang JH. Synthetic Story of a Blockbuster Drug: Reboxetine, a Potent Selective Norepinephrine Reuptake Inhibitor. Org Process Res Dev 2017. [DOI: 10.1021/acs.oprd.7b00265] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Danish Shahzad
- Department
of Chemistry, Quaid-i-Azam University, 45320 Islamabad, Pakistan
| | - Muhammad Faisal
- Department
of Chemistry, Quaid-i-Azam University, 45320 Islamabad, Pakistan
| | - Ameema Rauf
- Department
of Chemistry, University of Wah, Wah Cantt, Pakistan
| | - Jian-hua Huang
- School
of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China
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23
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Moriguchi S, Takano H, Kimura Y, Nagashima T, Takahata K, Kubota M, Kitamura S, Ishii T, Ichise M, Zhang MR, Shimada H, Mimura M, Meyer JH, Higuchi M, Suhara T. Occupancy of Norepinephrine Transporter by Duloxetine in Human Brains Measured by Positron Emission Tomography with (S,S)-[18F]FMeNER-D2. Int J Neuropsychopharmacol 2017; 20:957-962. [PMID: 29016875 PMCID: PMC5716070 DOI: 10.1093/ijnp/pyx069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/28/2017] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The norepinephrine transporter in the brain has been targeted in the treatment of psychiatric disorders. Duloxetine is a serotonin and norepinephrine reuptake inhibitor that has been widely used for the treatment of depression. However, the relationship between dose and plasma concentration of duloxetine and norepinephrine transporter occupancy in the human brain has not been determined. In this study, we examined norepinephrine transporter occupancy by different doses of duloxetine. METHODS We calculated norepinephrine transporter occupancies from 2 positron emission tomography scans using (S,S)-[18F]FMeNER-D2 before and after a single oral dose of duloxetine (20 mg, n = 3; 40 mg, n = 3; 60 mg, n =2). Positron emission tomography scans were performed from 120 to 180 minutes after an i.v. bolus injection of (S,S)-[18F]FMeNER-D2. Venous blood samples were taken to measure the plasma concentration of duloxetine just before and after the second positron emission tomography scan. RESULTS Norepinephrine transporter occupancy by duloxetine was 29.7% at 20 mg, 30.5% at 40 mg, and 40.0% at 60 mg. The estimated dose of duloxetine inducing 50% norepinephrine transporter occupancy was 76.8 mg, and the estimated plasma drug concentration inducing 50% norepinephrine transporter occupancy was 58.0 ng/mL. CONCLUSIONS Norepinephrine transporter occupancy by clinical doses of duloxetine was approximately 30% to 40% in human brain as estimated using positron emission tomography with (S,S)-[18F]FMeNER-D2.
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Affiliation(s)
- Sho Moriguchi
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura),Correspondence: Sho Moriguchi, MD, PhD, Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan ()
| | - Harumasa Takano
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Yasuyuki Kimura
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Tomohisa Nagashima
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Keisuke Takahata
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Manabu Kubota
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Soichiro Kitamura
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Tatsuya Ishii
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Masanori Ichise
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Ming-Rong Zhang
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Hitoshi Shimada
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Masaru Mimura
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Jeffrey H Meyer
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Makoto Higuchi
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
| | - Tetsuya Suhara
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Moriguchi, Takano, Kimura, Nagashima, Takahata, Kubota, Kitamura, Ishii, Ichise, Zhang, Shimada, Higuchi, and Suhara); Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan (Drs Moriguchi, Takahata, and Mimura); Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada (Drs Moriguchi and Meyer); Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura)
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[(18)F]FMeNER-D2: A systematic in vitro analysis of radio-metabolism. Nucl Med Biol 2016; 43:490-5. [PMID: 27236284 DOI: 10.1016/j.nucmedbio.2016.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 11/23/2022]
Abstract
INTRODUCTION The norepinephrine transporter (NET) presents an important target for therapy and diagnosis of ADHD and other neurodegenerative and psychiatric diseases. Thus, PET is the diagnostic method of choice, using radiolabeled NET-ligands derived from reboxetine. So far, [(18)F]FMeNER-D2 showed best pharmacokinetic and -dynamic properties. However, the disadvantage of reboxetine derived PET tracers is their high metabolic cleavage-resulting in impeding signals in the PET scans, which hamper a proper quantification of the NET in cortical areas. METHODS Metabolic stability testing was performed in vitro using a plethora of human and murine enzymes. RESULTS No metabolism was observed using monoamine oxidase A and B or catechol-O-methyl transferase. Incubation of [(18)F]FMeNER-D2 with CYP450-enzymes, predominantly located in the liver, led to a significant and fast metabolism of the tracer. Moreover, the arising three radiometabolites were found to be more polar than [(18)F]FMeNER-D2. Surprisingly, definitely no formation of free [(18)F]fluoride was observed. CONCLUSION According to our in vitro data, the interfering uptake in cortical regions might be attributed to these emerging radiometabolites but does not reflect bonding in bone due to defluorination. Further research on these radiometabolites is necessary to elucidate the in vivo situation. This might include an analysis of human blood samples after injection of [(18)F]FMeNER-D2, to enable a better correction of the PET-input function.
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Stehouwer JS, Goodman MM. Fluorine-18 Radiolabeled PET Tracers for Imaging Monoamine Transporters: Dopamine, Serotonin, and Norepinephrine. PET Clin 2016; 4:101-28. [PMID: 20216936 DOI: 10.1016/j.cpet.2009.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This review focuses on the development of fluorine-18 radiolabeled PET tracers for imaging the dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter (NET). All successful DAT PET tracers reported to date are members of the 3β-phenyl tropane class and are synthesized from cocaine. Currently available carbon-11 SERT PET tracers come from both the diphenylsulfide and 3β-phenyl nortropane class, but so far only the nortropanes have found success with fluorine-18 derivatives. NET imaging has so far employed carbon-11 and fluorine-18 derivatives of reboxetine but due to defluorination of the fluorine-18 derivatives further research is still necessary.
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Methods to Increase the Metabolic Stability of (18)F-Radiotracers. Molecules 2015; 20:16186-220. [PMID: 26404227 PMCID: PMC6332123 DOI: 10.3390/molecules200916186] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/20/2015] [Accepted: 08/26/2015] [Indexed: 11/17/2022] Open
Abstract
The majority of pharmaceuticals and other organic compounds incorporating radiotracers that are considered foreign to the body undergo metabolic changes in vivo. Metabolic degradation of these drugs is commonly caused by a system of enzymes of low substrate specificity requirement, which is present mainly in the liver, but drug metabolism may also take place in the kidneys or other organs. Thus, radiotracers and all other pharmaceuticals are faced with enormous challenges to maintain their stability in vivo highlighting the importance of their structure. Often in practice, such biologically active molecules exhibit these properties in vitro, but fail during in vivo studies due to obtaining an increased metabolism within minutes. Many pharmacologically and biologically interesting compounds never see application due to their lack of stability. One of the most important issues of radiotracers development based on fluorine-18 is the stability in vitro and in vivo. Sometimes, the metabolism of 18F-radiotracers goes along with the cleavage of the C-F bond and with the rejection of [18F]fluoride mostly combined with high background and accumulation in the skeleton. This review deals with the impact of radiodefluorination and with approaches to stabilize the C-F bond to avoid the cleavage between fluorine and carbon.
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Stehouwer JS, Birnbaum MS, Voll RJ, Owens MJ, Plott SJ, Bourke CH, Wassef MA, Kilts CD, Goodman MM. Synthesis, F-18 radiolabeling, and microPET evaluation of 3-(2,4-dichlorophenyl)-N-alkyl-N-fluoroalkyl-2,5-dimethylpyrazolo[1,5-a]pyrimidin-7-amines as ligands of the corticotropin-releasing factor type-1 (CRF1) receptor. Bioorg Med Chem 2015; 23:4286-4302. [PMID: 26145817 DOI: 10.1016/j.bmc.2015.06.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/04/2015] [Accepted: 06/12/2015] [Indexed: 12/28/2022]
Abstract
A series of 3-(2,4-dichlorophenyl)-N-alkyl-N-fluoroalkyl-2,5-dimethylpyrazolo[1,5-a]pyrimidin-7-amines were synthesized and evaluated as potential positron emission tomography (PET) tracers for the corticotropin-releasing factor type-1 (CRF1) receptor. Compounds 27, 28, 29, and 30 all displayed high binding affinity (⩽1.2 nM) to the CRF1 receptor when assessed by in vitro competition binding assays at 23 °C, whereas a decrease in affinity (⩾10-fold) was observed with compound 26. The logP7.4 values of [(18)F]26-[(18)F]29 were in the range of ∼2.2-2.8 and microPET evaluation of [(18)F]26-[(18)F]29 in an anesthetized male cynomolgus monkey demonstrated brain penetrance, but specific binding was not sufficient enough to differentiate regions of high CRF1 receptor density from regions of low CRF1 receptor density. Radioactivity uptake in the skull, and sphenoid bone and/or sphenoid sinus during studies with [(18)F]28, [(18)F]28-d8, and [(18)F]29 was attributed to a combination of [(18)F]fluoride generated by metabolic defluorination of the radiotracer and binding of intact radiotracer to CRF1 receptors expressed on mast cells in the bone marrow. Uptake of [(18)F]26 and [(18)F]27 in the skull and sphenoid region was rapid but then steadily washed out which suggests that this behavior was the result of binding to CRF1 receptors expressed on mast cells in the bone marrow with no contribution from [(18)F]fluoride.
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Affiliation(s)
- Jeffrey S Stehouwer
- Center for Systems Imaging, Department of Radiology and Imaging Sciences, Emory University, WWHC 209, 1841 Clifton Rd NE, Atlanta, GA 30329, USA.
| | - Matthew S Birnbaum
- Center for Systems Imaging, Department of Radiology and Imaging Sciences, Emory University, WWHC 209, 1841 Clifton Rd NE, Atlanta, GA 30329, USA
| | - Ronald J Voll
- Center for Systems Imaging, Department of Radiology and Imaging Sciences, Emory University, WWHC 209, 1841 Clifton Rd NE, Atlanta, GA 30329, USA
| | - Michael J Owens
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - Susan J Plott
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - Chase H Bourke
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - Michael A Wassef
- Center for Systems Imaging, Department of Radiology and Imaging Sciences, Emory University, WWHC 209, 1841 Clifton Rd NE, Atlanta, GA 30329, USA
| | - Clinton D Kilts
- Department of Psychiatry and Behavioral Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Mark M Goodman
- Center for Systems Imaging, Department of Radiology and Imaging Sciences, Emory University, WWHC 209, 1841 Clifton Rd NE, Atlanta, GA 30329, USA; Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
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Rami-Mark C, Berroterán-Infante N, Philippe C, Foltin S, Vraka C, Hoepping A, Lanzenberger R, Hacker M, Mitterhauser M, Wadsak W. Radiosynthesis and first preclinical evaluation of the novel norepinephrine transporter pet-ligand [(11)C]ME@HAPTHI. EJNMMI Res 2015; 5:113. [PMID: 26061602 PMCID: PMC4467816 DOI: 10.1186/s13550-015-0113-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/22/2015] [Indexed: 11/16/2022] Open
Abstract
Background The norepinephrine transporter (NET) has been demonstrated to be relevant to a multitude of neurological, psychiatric and cardiovascular pathologies. Due to the wide range of possible applications for PET imaging of the NET together with the limitations of currently available radioligands, novel PET tracers for imaging of the cerebral NET with improved pharmacological and pharmacodynamic properties are needed. Methods The present study addresses the radiosynthesis and first preclinical evaluation of the novel NET PET tracer [11C]Me@HAPTHI by describing its affinity, selectivity, metabolic stability, plasma free fraction, blood–brain barrier (BBB) penetration and binding behaviour in in vitro autoradiography. Results [11C]Me@HAPTHI was prepared and displayed outstanding affinity and selectivity as well as excellent in vitro metabolic stability, and it is likely to penetrate the BBB. Moreover, selective NET binding in in vitro autoradiography was observed in human brain and rat heart tissue samples. Conclusions All preclinical results and radiosynthetic key-parameters indicate that the novel benzothiadiazole dioxide-based PET tracer [11C]Me@HAPTHI is a feasible and improved NET radioligand and might prospectively facilitate clinical NET imaging. Electronic supplementary material The online version of this article (doi:10.1186/s13550-015-0113-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christina Rami-Mark
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria,
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Vanicek T, Spies M, Rami-Mark C, Savli M, Höflich A, Kranz GS, Hahn A, Kutzelnigg A, Traub-Weidinger T, Mitterhauser M, Wadsak W, Hacker M, Volkow ND, Kasper S, Lanzenberger R. The norepinephrine transporter in attention-deficit/hyperactivity disorder investigated with positron emission tomography. JAMA Psychiatry 2014; 71:1340-1349. [PMID: 25338091 PMCID: PMC4699255 DOI: 10.1001/jamapsychiatry.2014.1226] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
IMPORTANCE Attention-deficit/hyperactivity disorder (ADHD) research has long focused on the dopaminergic system's contribution to pathogenesis, although the results have been inconclusive. However, a case has been made for the involvement of the noradrenergic system, which modulates cognitive processes, such as arousal, working memory, and response inhibition, all of which are typically affected in ADHD. Furthermore, the norepinephrine transporter (NET) is an important target for frequently prescribed medication in ADHD. Therefore, the NET is suggested to play a critical role in ADHD. OBJECTIVE To explore the differences in NET nondisplaceable binding potential (NET BPND) using positron emission tomography and the highly selective radioligand (S,S)-[18F]FMeNER-D2 [(S,S)-2-(α-(2-[18F]fluoro[2H2]methoxyphenoxy)benzyl)morpholine] between adults with ADHD and healthy volunteers serving as controls. DESIGN, SETTING, AND PARTICIPANTS Twenty-two medication-free patients with ADHD (mean [SD] age, 30.7 [10.4] years; 15 [68%] men) without psychiatric comorbidities and 22 age- and sex-matched healthy controls (30.9 [10.6] years; 15 [68%] men) underwent positron emission tomography once. A linear mixed model was used to compare NET BPND between groups. MAIN OUTCOMES AND MEASURES The NET BPND in selected regions of interest relevant for ADHD, including the hippocampus, putamen, pallidum, thalamus, midbrain with pons (comprising a region of interest that includes the locus coeruleus), and cerebellum. In addition, the NET BPND was evaluated in thalamic subnuclei (13 atlas-based regions of interest). RESULTS We found no significant differences in NET availability or regional distribution between patients with ADHD and healthy controls in all investigated brain regions (F1,41<0.01; P=.96). Furthermore, we identified no significant association between ADHD symptom severity and regional NET availability. Neither sex nor smoking status influenced NET availability. We determined a significant negative correlation between age and NET availability in the thalamus (R2=0.29; P<.01 corrected) and midbrain with pons, including the locus coeruleus (R2=0.18; P<.01 corrected), which corroborates prior findings of a decrease in NET availability with aging in the human brain. CONCLUSIONS AND RELEVANCE Our results do not indicate involvement of changes in brain NET availability or distribution in the pathogenesis of ADHD. However, the noradrenergic transmitter system may be affected on a different level, such as in cortical regions, which cannot be reliably quantified with this positron emission tomography ligand. Alternatively, different key proteins of noradrenergic neurotransmission might be affected.
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Affiliation(s)
- Thomas Vanicek
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Marie Spies
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Christina Rami-Mark
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Markus Savli
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Anna Höflich
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Georg S. Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Andreas Hahn
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Alexandra Kutzelnigg
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Tatjana Traub-Weidinger
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Markus Mitterhauser
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Wadsak
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
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Vase KH, Peters D, Nielsen EØ, Alstrup AKO, Bender D. [11C]NS8880, a promising PET radiotracer targeting the norepinephrine transporter. Nucl Med Biol 2014; 41:758-64. [PMID: 25127515 DOI: 10.1016/j.nucmedbio.2014.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 06/05/2014] [Accepted: 06/17/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Positron emission tomography (PET) imaging of the norepinephrine transporter (NET) is still hindered by the availability of useful PET imaging probes. The present study describes the radiosynthesis and pre-clinical evaluation of a new compound, exo-3-(6-methoxypyridin-2-yloxy)-8-H-8-azabicyclo[3.2.1]octane (NS8880), targeting NET. NS8880 has an in vitro binding profile comparable to desipramine and is structurally not related to reboxetine. METHODS Labeling of NS8880 with [(11)C] was achieved by a non-conventional technique: substitution of pyridinyl fluorine with [(11)C]methanolate in a Boc-protected precursor. The isolated [(11)C]NS8880 was evaluated pre-clinically both in a pig model (PET scanning) and in a rat model (μPET scanning) and compared to (S,S)-[(11)C]-O-methylreboxetine ([(11)C]MeNER). RESULTS The radiolabeling technique yielded [(11)C]NS8880 in low (<10%) but still useful yields with high purity. The PET in vivo evaluation in pig and rat revealed a rapid brain uptake of [(11)C]NS8880 and fast obtaining of equilibrium. Highest binding was observed in thalamic and hypothalamic regions. Pretreatment with desipramine efficiently reduced binding of [(11)C]NS8880. CONCLUSION Based on the pre-clinical results obtained so far [(11)C]NS8880 displays promising properties for PET imaging of NET.
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Affiliation(s)
- Karina H Vase
- PET Center, Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
| | - Dan Peters
- DanPET AB, Rosenstigen 7, SE-216 19 Malmö, Sweden
| | | | - Aage K O Alstrup
- PET Center, Aarhus University Hospital, DK-8000 Aarhus C, Denmark
| | - Dirk Bender
- PET Center, Aarhus University Hospital, DK-8000 Aarhus C, Denmark
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Norepinephrine transporter occupancy by nortriptyline in patients with depression: a positron emission tomography study with (S,S)-[¹⁸F]FMeNER-D₂. Int J Neuropsychopharmacol 2014; 17:553-60. [PMID: 24345533 DOI: 10.1017/s1461145713001521] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Norepinephrine transporter (NET) plays important roles in the treatment of various neuropsychiatric disorders, such as depression and attention deficit hyperactivity disorder (ADHD). Nortriptyline is a NET-selective tricyclic antidepressant (TCAs) that has been widely used for the treatment of depression. Previous positron emission tomography (PET) studies have reported over 80% serotonin transporter occupancy with clinical doses of selective serotonin reuptake inhibitors (SSRIs), but there has been no report of NET occupancy in patients treated with relatively NET-selective antidepressants. In the present study, we used PET and (S,S)-[18¹⁸F]FMeNER-D₂ to investigate NET occupancies in the thalamus in 10 patients with major depressive disorder taking various doses of nortriptyline, who were considered to be responders to the treatment. Reference data for the calculation of occupancy were derived from age-matched healthy controls. The result showed approximately 50-70% NET occupancies in the brain as a result of the administration of 75-200 mg/d of nortriptyline. The estimated effective dose (ED₅₀) and concentration (EC₅₀) required to induce 50% occupancy was 65.9 mg/d and 79.8 ng/ml, respectively. Furthermore, as the minimum therapeutic level of plasma nortriptyline for the treatment of depression has been reported to be 70 ng/ml, our data indicate that this plasma nortriptyline concentration corresponds to approximately 50% NET occupancy measured with PET, suggesting that more than 50% of central NET occupancy would be appropriate for the nortriptyline treatment of patients with depression.
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Moon BS, Kim BS, Park C, Jung JH, Lee YW, Lee HY, Chi DY, Lee BC, Kim SE. [18F]Fluoromethyl-PBR28 as a Potential Radiotracer for TSPO: Preclinical Comparison with [11C]PBR28 in a Rat Model of Neuroinflammation. Bioconjug Chem 2014; 25:442-50. [DOI: 10.1021/bc400556h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Byung Seok Moon
- Department
of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Bom Sahn Kim
- Department
of Nuclear Medicine, Ewha Womans University Medical Center, Seoul, Korea
| | - Chansoo Park
- Department
of Chemistry, Sogang University, Seoul, Korea
| | - Jae Ho Jung
- Department
of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Youn Woo Lee
- Department
of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ho-Young Lee
- Department
of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Dae Yoon Chi
- Department
of Chemistry, Sogang University, Seoul, Korea
| | - Byung Chul Lee
- Department
of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea
- Advanced Institutes of Convergence Technology, Suwon, Korea
| | - Sang Eun Kim
- Department
of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea
- Advanced Institutes of Convergence Technology, Suwon, Korea
- Department
of Transdisciplinary Studies, Graduate School of Convergence Science
and Technology, Seoul National University, Seoul, Korea
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Hortala L, Arnaud J, Roux P, Oustric D, Boulu L, Oury-Donat F, Avenet P, Rooney T, Alagille D, Barret O, Tamagnan G, Barth F. Synthesis and preliminary evaluation of a new fluorine-18 labelled triazine derivative for PET imaging of cannabinoid CB2 receptor. Bioorg Med Chem Lett 2014; 24:283-7. [DOI: 10.1016/j.bmcl.2013.11.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/08/2013] [Accepted: 11/10/2013] [Indexed: 01/26/2023]
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Norepinephrine transporter occupancy in the human brain after oral administration of quetiapine XR. Int J Neuropsychopharmacol 2013; 16:2235-44. [PMID: 23809226 DOI: 10.1017/s1461145713000680] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Quetiapine, originally developed as an antipsychotic, demonstrates efficacy in clinical studies of schizophrenia, bipolar mania and depression, major depressive disorder and generalized anxiety disorder. This broad spectrum of efficacy was not predicted from the preclinical pharmacology of quetiapine. Binding studies in vitro show that quetiapine and its major active human metabolite, norquetiapine, have moderate to high affinity for dopamine D2 and serotonin 5-HT2A receptors, while norquetiapine alone has high affinity for the norepinephrine transporter (NET). This positron emission tomography (PET) study measured NET occupancy in human subjects treated with extended-release quetiapine (quetiapine XR) at doses relevant in the treatment of depression. PET measurements using the specific NET radioligand (S,S)-[(18)F]FMeNER-D2 were performed before and after quetiapine XR treatment at 150 and 300 mg/d for 6-8 d in nine healthy males (aged 21-33 yr). Regions of interest were defined for the thalamus, using the caudate as reference region. NET occupancy was calculated using a target:reference region ratio method. Plasma concentrations of quetiapine and norquetiapine were monitored during PET measurements. Following quetiapine XR treatment, the mean NET occupancy in the thalamus was 19 and 35%, respectively, at quetiapine XR doses of 150 and 300 mg/d. The estimated plasma concentration of norquetiapine corresponding to 50% NET occupancy was 161 ng/ml. This is the first demonstration of NET occupancy by an antipsychotic in the human brain. NET inhibition is accepted as a mechanism of antidepressant activity. NET occupancy may therefore contribute to the broad spectrum of efficacy of quetiapine.
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Rami-Mark C, Zhang MR, Mitterhauser M, Lanzenberger R, Hacker M, Wadsak W. [18F]FMeNER-D2: reliable fully-automated synthesis for visualization of the norepinephrine transporter. Nucl Med Biol 2013; 40:1049-54. [PMID: 24100201 PMCID: PMC3919152 DOI: 10.1016/j.nucmedbio.2013.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 11/19/2022]
Abstract
PURPOSE In neurodegenerative diseases and neuropsychiatric disorders dysregulation of the norepinephrine transporter (NET) has been reported. For visualization of NET availability and occupancy in the human brain PET imaging can be used. Therefore, selective NET-PET tracers with high affinity are required. Amongst these, [(18)F]FMeNER-D2 is showing the best results so far. Furthermore, a reliable fully automated radiosynthesis is a prerequisite for successful application of PET-tracers. The aim of this work was the automation of [(18)F]FMeNER-D2 radiolabelling for subsequent clinical use. The presented study comprises 25 automated large-scale syntheses, which were directly applied to healthy volunteers and adult patients suffering from attention deficit hyperactivity disorder (ADHD). PROCEDURES Synthesis of [(18)F]FMeNER-D2 was automated within a Nuclear Interface Module. Starting from 20-30 GBq [(18)F]fluoride, azeotropic drying, reaction with Br2CD2, distillation of 1-bromo-2-[(18)F]fluoromethane-D2 ([(18)F]BFM) and reaction of the pure [(18)F]BFM with unprotected precursor NER were optimized and completely automated. HPLC purification and SPE procedure were completed, formulation and sterile filtration were achieved on-line and full quality control was performed. RESULTS Purified product was obtained in a fully automated synthesis in clinical scale allowing maximum radiation safety and routine production under GMP-like manner. So far, more than 25 fully automated syntheses were successfully performed, yielding 1.0-2.5 GBq of formulated [(18)F]FMeNER-D2 with specific activities between 430 and 1707 GBq/μmol within 95 min total preparation time. CONCLUSIONS A first fully automated [(18)F]FMeNER-D2 synthesis was established, allowing routine production of this NET-PET tracer under maximum radiation safety and standardization.
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Affiliation(s)
- Christina Rami-Mark
- Radiochemistry and Biomarker Development Unit, Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria
- Department of Inorganic Chemistry, University of Vienna, Austria
| | - Ming-Rong Zhang
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Markus Mitterhauser
- Radiochemistry and Biomarker Development Unit, Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria
- Hospital Pharmacy of the General Hospital of Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - Marcus Hacker
- Radiochemistry and Biomarker Development Unit, Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria
| | - Wolfgang Wadsak
- Radiochemistry and Biomarker Development Unit, Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria
- Department of Inorganic Chemistry, University of Vienna, Austria
- Corresponding author. Medical University of Vienna - Department of Nuclear Medicine, Radiochemistry and Biomarker Development Unit, Waehringer Guertel 18-20, A-1090 Vienna, Austria. Tel.: + 43 1 40400 5255; fax: + 43 1 40400 1559.
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Occupancy of serotonin and norepinephrine transporter by milnacipran in patients with major depressive disorder: a positron emission tomography study with [(11)C]DASB and (S,S)-[(18)F]FMeNER-D(2). Int J Neuropsychopharmacol 2013; 16:937-43. [PMID: 23067569 DOI: 10.1017/s1461145712001009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Antidepressants used for treatment of depression exert their efficacy by blocking reuptake at serotonin transporters (5-HTT) and/or norepinephrine transporters (NET). Recent studies suggest that serotonin and norepinephrine reuptake inhibitors that block both 5-HTT and NET have better tolerability than tricyclic antidepressants and may have higher efficacy compared to selective serotonin reuptake inhibitors. Previous positron emission tomography (PET) studies have reported >80% 5-HTT occupancy with clinical doses of antidepressants, but there has been no report of NET occupancy in patients treated with antidepressants. In the present study, we investigated both 5-HTT and NET occupancies by PET using radioligands [(11)C]DASB and (S,S)-[(18)F]FMeNER-D(2), in six patients, each with major depressive disorder (MDD), using various doses of milnacipran. Our data show that mean 5-HTT occupancy in the thalamus was 33.0% at 50 mg, 38.6% at 100 mg, 60.0% at 150 mg and 61.5% at 200 mg. Mean NET occupancy in the thalamus was 25.3% at 25 mg, 40.0% at 100 mg, 47.3% at 125 mg and 49.9% at 200 mg. Estimated ED(50) was 122.5 mg with the dose for 5-HTT and 149.9 mg for NET. Both 5-HTT and NET occupancies were observed in a dose-dependent manner. Both 5-HTT and NET occupancies were about 40% by milnacipran at 100 mg, the dose most commonly administered to MDD patients.
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Norquetiapine and depressive symptoms in initially antipsychotic-naive first-episode schizophrenia. J Clin Psychopharmacol 2013; 33:266-9. [PMID: 23422401 DOI: 10.1097/jcp.0b013e318287acc9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Takahashi H. Molecular neuroimaging of emotional decision-making. Neurosci Res 2013; 75:269-74. [DOI: 10.1016/j.neures.2013.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 01/27/2013] [Accepted: 01/29/2013] [Indexed: 12/19/2022]
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SERT and NET occupancy by venlafaxine and milnacipran in nonhuman primates: a PET study. Psychopharmacology (Berl) 2013; 226:147-53. [PMID: 23090625 DOI: 10.1007/s00213-012-2901-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 09/27/2012] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Serotonin and norepinephrine reuptake inhibitors (SNRIs) are antidepressants which have high affinity to both serotonin transporter (SERT) and norepinephrine transporter (NET). In studies in vitro, SNRIs have been reported to show a large variability in the affinity ratio between SERT and NET. For instance, the reported affinity ratio is about 30 for venlafaxine and 1.6 for milnacipran. In this study in nonhuman primates, we aimed to investigate the relationship between SERT and NET affinity by measuring the in vivo occupancy at both transporters of venlafaxine and milnacipran. METHODS PET measurements with [(11)C]MADAM and [(18)F]FMeNER-D(2) were performed in two female cynomolgus monkeys at baseline and after pretreatment with venlafaxine and milnacipran, respectively. Relationships between dose, plasma concentration, and transporter occupancy were evaluated by saturation analysis using a hyperbolic function. Binding affinity (Kd(plasma)) was expressed by the dose or plasma concentration at which 50 % of the transporter was occupied. RESULTS SERT and NET occupancy by venlafaxine and milnacipran increased in a dose and plasma concentration-dependent manner. The Kd(plasma) ratio of SERT to NET was 1.9 for venlafaxine and 0.6 for milnacipran. CONCLUSIONS In this nonhuman primate PET study, the affinity in vivo for SERT and NET, respectively, was shown to be at a similar level for venlafaxine and milnacipran. Both drugs were found to produce balanced inhibition of SERT and NET binding. This observation is not consistent with previous in vitro binding data and illustrates the need to characterize antidepressants at in vivo condition.
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Mark C, Bornatowicz B, Mitterhauser M, Hendl M, Nics L, Haeusler D, Lanzenberger R, Berger ML, Spreitzer H, Wadsak W. Development and automation of a novel NET-PET tracer: [11C]Me@APPI. Nucl Med Biol 2013; 40:295-303. [DOI: 10.1016/j.nucmedbio.2012.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 11/07/2012] [Accepted: 11/15/2012] [Indexed: 10/27/2022]
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Alstrup AKO, Smith DF. Anaesthesia for positron emission tomography scanning of animal brains. Lab Anim 2013; 47:12-8. [PMID: 23349451 DOI: 10.1258/la.2012.011173] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Positron emission tomography (PET) provides a means of studying physiological and pharmacological processes as they occur in the living brain. Mice, rats, dogs, cats, pigs and non-human primates are often used in studies using PET. They are commonly anaesthetized with ketamine, propofol or isoflurane in order to prevent them from moving during the imaging procedure. The use of anaesthesia in PET studies suffers, however, from the drawback of possibly altering central neuromolecular mechanisms. As a result, PET findings obtained in anaesthetized animals may fail to correctly represent normal properties of the awake brain. Here, we review findings of PET studies carried out either in both awake and anaesthetized animals or in animals given at least two different anaesthetics. Such studies provide a means of estimating the extent to which anaesthesia affects the outcome of PET neuroimaging in animals. While no final conclusion can be drawn concerning the 'best' general anaesthetic for PET neuroimaging in laboratory animals, such studies provide findings that can enhance an understanding of neurobiological mechanisms in the living brain.
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Affiliation(s)
- Aage Kristian Olsen Alstrup
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospitals, Nørrebrogade 44, 10G, DK-8000 Aarhus C, Denmark.
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Takahashi H. Monoamines and assessment of risks. Curr Opin Neurobiol 2012; 22:1062-7. [DOI: 10.1016/j.conb.2012.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/08/2012] [Accepted: 06/12/2012] [Indexed: 10/28/2022]
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Doi H, Goto M, Suzuki M. Pd0-Mediated Rapid C-[18F]Fluoromethylation by the Cross-Coupling Reaction of a [18F]Fluoromethyl Halide with an Arylboronic Acid Ester: Novel Method for the Synthesis of a 18F-Labeled Molecular Probe for Positron Emission Tomography. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120151] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hisashi Doi
- RIKEN Center for Molecular Imaging Science (CMIS)
| | - Miki Goto
- RIKEN Center for Molecular Imaging Science (CMIS)
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Kanegawa N, Kiyono Y, Sugitaa T, Kuge Y, Fujibayasi Y, Saji H. Norepinephrine Transporter Imaging in the Brain of a Rat Model of Depression Using Radioiodinated (2S, αS)-2-(α-(2-iodophenoxy)benzyl)morpholine. Mol Imaging 2012. [DOI: 10.2310/7290.2011.00049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To visualize the norepinephrine transporters (NETs) in various brain diseases, we developed radioiodinated (2S,αS)-2-(α-(2-iodophenoxy)benzyl)morpholine ((S,S)-IPBM). This radioligand achieved the basic requirements for NET imaging. In this study, we assessed the potential of radioiodinated (S,S)-IPBM as an imaging biomarker of NET to obtain diagnostic information about depression in relation to NET expression in the brain using a rat depression model. The ex vivo autoradiographic experiments using the (S,S)-[125I]IPBM showed significantly lower accumulation of radioactivity in the locus coeruleus (LC) and the anteroventricular thalamic nucleus (AVTN) of the depression group than in those of the control group. Consequently, in vitro autoradiographic experiments showed that NET maximum binding (Bmax) values in the LC and AVTN, known as NET-rich regions, were significantly decreased in the rat model of depression when compared to those of the control rats. In addition, there was an extremely good correlation between NET Bmax and (S,S)-IPBM accumulation ( r = .98), an indication of radioiodinated IPBM as a quantitative NET imaging biomarker. The reduction in(S,S)-[125I]IPBM accumulation in the rat model of depression correlated with that of NET density. These results suggest that (S,S)-[123I]IPBM has potential as an imaging biomarker of NET to obtain diagnostic information about major depression.
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Affiliation(s)
- Naoki Kanegawa
- From the Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan; Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan; Central Institute of Isotope Science, Hokkaido University, Hokkaido, Japan; and Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yasushi Kiyono
- From the Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan; Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan; Central Institute of Isotope Science, Hokkaido University, Hokkaido, Japan; and Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Taku Sugitaa
- From the Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan; Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan; Central Institute of Isotope Science, Hokkaido University, Hokkaido, Japan; and Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yuji Kuge
- From the Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan; Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan; Central Institute of Isotope Science, Hokkaido University, Hokkaido, Japan; and Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yasushisa Fujibayasi
- From the Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan; Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan; Central Institute of Isotope Science, Hokkaido University, Hokkaido, Japan; and Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hideo Saji
- From the Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan; Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan; Central Institute of Isotope Science, Hokkaido University, Hokkaido, Japan; and Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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Jahan M, Eriksson O, Johnström P, Korsgren O, Sundin A, Johansson L, Halldin C. Decreased defluorination using the novel beta-cell imaging agent [18F]FE-DTBZ-d4 in pigs examined by PET. EJNMMI Res 2011; 1:33. [PMID: 22214308 PMCID: PMC3284452 DOI: 10.1186/2191-219x-1-33] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/05/2011] [Indexed: 11/26/2022] Open
Abstract
Background Fluorine-18 dihydrotetrabenazine [DTBZ] analogues, which selectively target the vesicular monoamine transporter 2 [VMAT2], have been extensively studied for in vivo quantification of beta cell mass by positron-emission tomography [PET]. This study describes a novel deuterated radioligand [18F]fluoroethyl [FE]-DTBZ-d4, aimed to increase the stability against in vivo defluorination previously observed for [18F]FE-DTBZ. Methods [18F]FE-DTBZ-d4 was synthesized by alkylation of 9-O-desmethyl-(+)-DTBZ precursor with deuterated [18F]FE bromide ([18F]FCD2CD2Br). Radioligand binding potential [BP] was assessed by an in vitro saturation homogenate binding assay using human endocrine and exocrine pancreatic tissues. In vivo pharmacokinetics and pharmacodynamics [PK/PD] was studied in a porcine model by PET/computed tomography, and the rate of defluorination was quantified by compartmental modeling. Results [18F]FE-DTBZ-d4 was produced in reproducible good radiochemical yield in 100 ± 20 min. Radiochemical purity of the formulated product was > 98% for up to 5 h with specific radioactivities that ranged from 192 to 529 GBq/μmol at the end of the synthesis. The in vitro BP for VMAT2 in the islet tissue was 27.0 ± 8.8, and for the exocrine tissue, 1.7 ± 1.0. The rate of in vivo defluorination was decreased significantly (kdefluorination = 0.0016 ± 0.0007 min-1) compared to the non-deuterated analogue (kdefluorination = 0.012 ± 0.002 min-1), resulting in a six fold increase in half-life stability. Conclusions [18F]FE-DTBZ-d4 has similar PK and PD properties for VMAT2 imaging as its non-deuterated analogue [18F]FE-DTBZ in addition to gaining significantly increased stability against defluorination. [18F]FE-DTBZ-d4 is a prime candidate for future preclinical and clinical studies on focal clusters of beta cells, such as in intramuscular islet grafts.
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Affiliation(s)
- Mahabuba Jahan
- Karolinska Institutet, Department of Clinical Neuroscience, Centre for Psychiatry Research, Building R5:U1, Karolinska University Hospital, SE 171 76, Stockholm, Sweden.
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Kristensen AS, Andersen J, Jørgensen TN, Sørensen L, Eriksen J, Loland CJ, Strømgaard K, Gether U. SLC6 neurotransmitter transporters: structure, function, and regulation. Pharmacol Rev 2011; 63:585-640. [PMID: 21752877 DOI: 10.1124/pr.108.000869] [Citation(s) in RCA: 601] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The neurotransmitter transporters (NTTs) belonging to the solute carrier 6 (SLC6) gene family (also referred to as the neurotransmitter-sodium-symporter family or Na(+)/Cl(-)-dependent transporters) comprise a group of nine sodium- and chloride-dependent plasma membrane transporters for the monoamine neurotransmitters serotonin (5-hydroxytryptamine), dopamine, and norepinephrine, and the amino acid neurotransmitters GABA and glycine. The SLC6 NTTs are widely expressed in the mammalian brain and play an essential role in regulating neurotransmitter signaling and homeostasis by mediating uptake of released neurotransmitters from the extracellular space into neurons and glial cells. The transporters are targets for a wide range of therapeutic drugs used in treatment of psychiatric diseases, including major depression, anxiety disorders, attention deficit hyperactivity disorder and epilepsy. Furthermore, psychostimulants such as cocaine and amphetamines have the SLC6 NTTs as primary targets. Beginning with the determination of a high-resolution structure of a prokaryotic homolog of the mammalian SLC6 transporters in 2005, the understanding of the molecular structure, function, and pharmacology of these proteins has advanced rapidly. Furthermore, intensive efforts have been directed toward understanding the molecular and cellular mechanisms involved in regulation of the activity of this important class of transporters, leading to new methodological developments and important insights. This review provides an update of these advances and their implications for the current understanding of the SLC6 NTTs.
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Affiliation(s)
- Anders S Kristensen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Takano A, Nag S, Gulyás B, Halldin C, Farde L. NET occupancy by clomipramine and its active metabolite, desmethylclomipramine, in non-human primates in vivo. Psychopharmacology (Berl) 2011; 216:279-86. [PMID: 21336575 DOI: 10.1007/s00213-011-2212-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 01/28/2011] [Indexed: 11/29/2022]
Abstract
RATIONALE Norepinephrine transporter (NET) is one of the key targets for antidepressants such as combined serotonin and norepinephrine reuptake inhibitors as well as some of the tricyclic antidepressants. Clomipramine, a tricyclic antidepressant, has been reported to have an active metabolite, desmethylclomipramine, which has high affinity for NET in vitro. However, the NET occupancy of clomipramine and desmethylclomipramine has not fully been evaluated in vivo. OBJECTIVES In this positron emission tomography (PET) study, we investigate NET occupancy by clomipramine and desmethylclomipramine, respectively, in non-human primates with a selective radioligand for NET, (S,S)-[(18)F]FMeNER-D(2). METHODS PET measurements were performed with (S,S)-[(18)F]FMeNER-D(2) at baseline and after the intravenous administration of clomipramine and desmethylclomipramine, respectively. NET binding was calculated with the simplified reference tissue model using the caudate as reference region. NET occupancy was calculated as the difference in NET binding between the baseline and pretreatment condition. The relationship between NET occupancy and dose/plasma concentration was evaluated using hyperbolic functions. RESULTS NET occupancy by both clomipramine and desmethylclomipramine increased in a dose and plasma concentration-dependent manner. The mean Kd values, expressed as the dose or plasma concentration at which 50% of NET was occupied, were 0.44 mg/kg and 24.5 ng/ml for clomipramine and 0.11 mg/kg and 4.4 ng/ml for desmethylclomipramine. CONCLUSIONS Not only desmethylclomipramine but also clomipramine was demonstrated to occupy NET in the non-human primate in vivo. It can thus be assumed that NET occupancy during clinical treatment with clomipramine is a combined effect of unchanged clomipramine and its main metabolite desmethylclomipramine.
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Affiliation(s)
- Akihiro Takano
- Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, 171 76, Stockholm, Sweden.
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Sekine M, Maeda J, Shimada H, Nogami T, Arakawa R, Takano H, Higuchi M, Ito H, Okubo Y, Suhara T. Central nervous system drug evaluation using positron emission tomography. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2011; 9:9-16. [PMID: 23431048 PMCID: PMC3568655 DOI: 10.9758/cpn.2011.9.1.9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 12/20/2022]
Abstract
In conventional pharmacological research in the field of mental disorders, pharmacological effect and dose have been estimated by ethological approach and in vitro data of affinity to the site of action. In addition, the frequency of administration has been estimated from drug kinetics in blood. However, there is a problem regarding an objective index of drug effects in the living body. Furthermore, the possibility that the concentration of drug in blood does not necessarily reflect the drug kinetics in target organs has been pointed out. Positron emission tomography (PET) techniques have made progress for more than 20 years, and made it possible to measure the distribution and kinetics of small molecule components in living brain. In this article, we focused on rational drug dosing using receptor occupancy and proof-of-concept of drugs in the drug development process using PET.
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Affiliation(s)
- Mizuho Sekine
- Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan. ; Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan
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Xu R, Hong J, Morse CL, Pike VW. Synthesis, structure-affinity relationships, and radiolabeling of selective high-affinity 5-HT4 receptor ligands as prospective imaging probes for positron emission tomography. J Med Chem 2010; 53:7035-47. [PMID: 20812727 DOI: 10.1021/jm100668r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a search for high-affinity receptor ligands that might serve for development as radioligands for the imaging of brain 5-HT(4) receptors in vivo with positron emission tomography (PET), structural modifications were made to the high-affinity 5-HT(4) antagonist (1-butylpiperidin-4-yl)methyl 8-amino-7-iodo-2,3-dihydrobenzo[b][1,4]dioxine-5-carboxylate (1, SB 207710). These modifications were made mainly on the aryl side of the ester bond to permit possible rapid labeling of the carboxylic acid component with a positron emitter, either carbon-11 (t(1/2) = 20.4 min) or fluorine-18 (t(1/2) = 109.7 min), and included (i) replacement of the iodine atom with a small substituent such as nitrile, methyl, or fluoro, (ii) methylation of the 8-amino group, (iii) opening of the dioxan ring, and (iv) alteration of the length of the N-alkyl goup. High-affinity ligands were discovered for recombinant human 5-HT(4) receptors with amenability to labeling with a positron emitter and potential for development as imaging probes. The ring-opened radioligand, (([methoxy-(11)C]1-butylpiperidin-4-yl)methyl 4-amino-3-methoxybenzoate; [(11)C]13), showed an especially favorable array of properties for future evaluation as a PET radioligand for brain 5-HT(4) receptors.
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Affiliation(s)
- Rong Xu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, USA
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Gallezot JD, Weinzimmer D, Nabulsi N, Lin SF, Fowles K, Sandiego C, McCarthy TJ, Maguire RP, Carson RE, Ding YS. Evaluation of [(11)C]MRB for assessment of occupancy of norepinephrine transporters: Studies with atomoxetine in non-human primates. Neuroimage 2010; 56:268-79. [PMID: 20869448 DOI: 10.1016/j.neuroimage.2010.09.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 09/16/2010] [Indexed: 12/15/2022] Open
Abstract
[(11)C]MRB is one of the most promising radioligands used to measure brain norepinephrine transporters (NET) with positron emission tomography (PET). The objective of this study was to evaluate the suitability of [(11)C]MRB for drug occupancy studies of NET using atomoxetine (ATX), a NET uptake inhibitor used in the treatment of depression and attention-deficit hyperactivity disorder (ADHD). A second goal of the study was identification of a suitable reference region. Ten PET studies were performed in three anesthetized rhesus monkeys following an infusion of ATX or placebo. [(11)C]MRB arterial input functions and ATX plasma levels were also measured. A dose-dependent reduction of [(11)C]MRB volume of distribution was observed after correction for [(11)C]MRB plasma free fraction. ATX IC(50) was estimated to be 31 ± 10ng/mL plasma. This corresponds to an effective dose (ED(50)) of 0.13mg/kg, which is much lower than the therapeutic dose of ATX in ADHD (1.0-1.5mg/kg). [(11)C]MRB binding potential BP(ND) in the thalamus was estimated to be 1.8 ± 0.3. Defining a reference region for a NET radiotracer is challenging due to the widespread and relatively uniform distribution of NET in the brain. Three regions were evaluated for use as reference region: caudate, putamen and occipital cortex. Caudate was found to be the most suitable for preclinical drug occupancy studies in rhesus monkeys. The IC(50) estimate obtained using MRTM2 BP(ND) without arterial blood sampling was 21 ± 3ng/mL (using caudate as the reference region). This study demonstrated that [(11)C]MRB is suitable for drug occupancy studies of NET.
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