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Saednia S, Emami S, Moslehi M, Hosseinimehr SJ. Insights into the development of 99mTc-radioligands for serotonergic receptors imaging: Synthesis, labeling, In vitro, and In vivo studies. Eur J Med Chem 2024; 270:116349. [PMID: 38555856 DOI: 10.1016/j.ejmech.2024.116349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/02/2024]
Abstract
Serotonergic (5-hydroxytryptamine; 5-HT) receptors play critical roles in neurological and psychological disorders such as schizophrenia, anxiety, depression, and Alzheimer's diseases. Therefore, it is particularly important to develop novel radioligands or modify the existing ones to identify the serotonergic receptors involved in psychiatric disorders. Among the 16 subtypes of serotonergic systems, only technetium-99m based radiopharmaceuticals have been evaluated for serotonin-1A (5-HT1A), serotonin-2A (5-HT2A), 5-HT1A/7 heterodimers and serotonin receptor neurotransmitter (SERT). This review focuses on recent efforts in the design, synthesis and evaluation of 99mTc-radioligands used for single photon emission computerized tomography (SPECT) imaging of serotonergic (5-HT) receptors. Additionally, the discussion will cover aspects such as chemical structure, in vitro/vivo stability, affinity toward serotonin receptors, blood-brain barrier permeation (BBB), and biodistribution study.
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Affiliation(s)
- Shahnaz Saednia
- Farabi Hospital, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Saeed Emami
- Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Masoud Moslehi
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
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Sun M, Xiao H, Hong H, Zhang A, Zhang Y, Liu Y, Zhu L, Kung HF, Qiao J. Rapid screening of nine unradiolabeled candidate compounds as PET brain imaging agents using cassette-wave microdosing and LC-MS/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1121:28-38. [PMID: 31100605 DOI: 10.1016/j.jchromb.2019.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 11/17/2022]
Abstract
The R&D of PET imaging agents is a complex system engineering, simplifying screening steps and increasing screening efficiency have become popular issues. The purpose of this study is to develop a new screening procedure using cassette-wave microdosing and LC-MS/MS to enhance the screening throughput of unradiolabeled candidate compounds as PET imaging agents. Nine compounds were divided into 3 sets and made into 3 cassettes. Fifteen rats were randomly divided into 3 groups, and every animal received three intravenous bolus injections at three different time points; the doses were at microdose levels. This dosing approach takes advantage of temporal and spatial differences and is likened to an input wave; therefore, this approach was named cassette-wave microdosing. The samples of different brain regions such as the hypothalamus, striatum, hippocampus, cortex, cerebellum and the remainder of the brain were detected by LC-MS/MS analysis. The research potential of the compounds as PET imaging agents is evaluated in terms of brain biodistribution data. The screening method is rapid, highly efficient, reliable and reduces animal usage. Additionally, it can shorten the evaluation process of radiopharmaceuticals and enhance the screening throughput of PET radiopharmaceuticals without the use of radioactive agents.
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Affiliation(s)
- Mingyue Sun
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Hao Xiao
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Haiyan Hong
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Aili Zhang
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Yan Zhang
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Yajing Liu
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Lin Zhu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China; Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Hank F Kung
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China.
| | - Jinping Qiao
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China.
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3
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Zhang Y, Liu F, Xiao H, Yao X, Li G, Choi SR, Ploessl K, Zha Z, Zhu L, Kung HF. Fluorine-18 labeled diphenyl sulfide derivatives for imaging serotonin transporter (SERT) in the brain. Nucl Med Biol 2018; 66:1-9. [PMID: 30096380 DOI: 10.1016/j.nucmedbio.2018.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/15/2018] [Accepted: 06/28/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Serotonin transporters (SERT) play an important role in controlling serotonin concentration in the synaptic cleft and in managing postsynaptic signal transduction. Inhibitors of SERT binding are well known as selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, sertraline, paroxetine, and escitalopram, that are commonly prescribed antidepressants. Positron emission tomography (PET) and single photon emission tomography (SPECT) imaging agents targeting SERT may be useful for studying its function and providing a tool for monitoring drug treatment. METHODS A series of novel 18F-labeled diphenyl sulfide derivatives were prepared and tested for their binding affinity. Among them, 2-((2-((dimethylamino)-methyl)-4-(2-(2-fluoroethoxy)ethoxy)phenyl)thio)aniline, 1, which showed excellent binding toward serotonin transporter (SERT) in the brain (Ki = 0.09 nM), was selected for further evaluation. An active OTs intermediate, 7, was treated with [18F]F-/K222 to provide [18F]1 in one step and in high radiochemical yields. This new SERT targeting agent was evaluated in rats by biodistribution studies and animal PET imaging studies. RESULTS The radiolabeling reaction led to the desired [18F]1. After HPLC purification no-carrier-added [18F]1 was obtained (radiochemical yield, 23-47% (n = 10,); radiochemical purity >99%; molar activity, 15-28 GBq/μmol). Biodistribution studies with [18F]1 showed good brain uptake (1.04% dose/g at 2 min post-injection), high uptake into the hypothalamus (1.55% dose/g at 30 min), and a high target-to-non-target (hypothalamus to cerebellum) ratio of 6.1 at 120 min post-injection. A PET imaging study in normal rats showed excellent uptake in the midbrain and thalamus regions known to be rich in SERT binding sites at 60 min after iv injection. Chasing experiment with escitalopram (iv, 2 mg/kg) in a rat at 60 min after iv injection caused a noticeable reduction in the regional radioactivity and the target-to-non-target ratio, suggesting binding by [18F]1 was highly specific and reversible for SERT binding sites in the brain. CONCLUSIONS A novel diphenyl sulfide derivative, [18F]1 for SERT imaging was successfully prepared and evaluated. Results suggest that this new chemical entity is targeting SERT binding sites in the brain, and it is a suitable candidate for future commercial development.
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Affiliation(s)
- Yan Zhang
- Key Laboratory of Radiopharmaceuticals (College of Chemistry), Beijing Normal University, Ministry of Education, Beijing, 100875, China
| | - Futao Liu
- Key Laboratory of Radiopharmaceuticals (College of Chemistry), Beijing Normal University, Ministry of Education, Beijing, 100875, China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hao Xiao
- Key Laboratory of Radiopharmaceuticals (College of Chemistry), Beijing Normal University, Ministry of Education, Beijing, 100875, China
| | - Xinyue Yao
- Key Laboratory of Radiopharmaceuticals (College of Chemistry), Beijing Normal University, Ministry of Education, Beijing, 100875, China
| | - Genxun Li
- Key Laboratory of Radiopharmaceuticals (College of Chemistry), Beijing Normal University, Ministry of Education, Beijing, 100875, China
| | - Seok Rye Choi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Karl Ploessl
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhihao Zha
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Lin Zhu
- Key Laboratory of Radiopharmaceuticals (College of Chemistry), Beijing Normal University, Ministry of Education, Beijing, 100875, China; Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
| | - Hank F Kung
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Liu F, Zhu L, Choi SR, Plössl K, Zha Z, Kung HF. Deuterium-substituted 2-(2′-((dimethylamino)methyl)-4′-[18
F](fluoropropoxy)phenylthio)benzenamine as a serotonin transporter imaging agent. J Labelled Comp Radiopharm 2018; 61:576-585. [DOI: 10.1002/jlcr.3626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Futao Liu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education; Beijing Normal University; Beijing P. R. China
- Department of Radiology; University of Pennsylvania; Philadelphia Pennsylvania USA
| | - Lin Zhu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education; Beijing Normal University; Beijing P. R. China
| | - Seok Rye Choi
- Department of Radiology; University of Pennsylvania; Philadelphia Pennsylvania USA
| | - Karl Plössl
- Department of Radiology; University of Pennsylvania; Philadelphia Pennsylvania USA
| | - Zhihao Zha
- Department of Radiology; University of Pennsylvania; Philadelphia Pennsylvania USA
| | - Hank F. Kung
- Department of Radiology; University of Pennsylvania; Philadelphia Pennsylvania USA
- Five Eleven Pharma Inc; Philadelphia Pennsylvania USA
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Developing a cassette microdosing approach to enhance the throughput of PET imaging agent screening. J Pharm Biomed Anal 2018. [PMID: 29533858 DOI: 10.1016/j.jpba.2018.02.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cassette dosing is also known as N-in-One dosing: several compounds are simultaneously administrated to a single animal and then the samples are rapidly detected by LC-MS/MS. This approach is a successful strategy to enhance the efficiency of drug discovery and reduce animal usage. However, no report on the utility of the cassette approach in radiotracer discovery has appeared in the literature. This study designed a cassette microdose with LC-MS/MS method to enhance the throughput for screening radiopharmaceutical biodistribution in the rat brain directly. Three unradiolabeled compounds (FPBM FPBM2 and AV-133) were chosen as model drugs administrated intravenously to the rats as a cassette as opposed to discrete study. The rat brain biodistribution data, target localization, the differential uptake ratio (%ID/g) and the brain tissue-specific binding ratio were obtained by the LC-MS/MS analysis. These data matched very well with the values obtained by the standard radioactivity measurements. Moreover, no significant differences between discrete dosing and cassette dosing were observed. By circumventing the need for radiolabeled molecules, this method may be high-throughput and safe for the research and development of new PET imaging agents. The combination of cassette microdosing and LC-MS/MS would be a medium throughput screening tool at an early stage in the discovery/development process of PET imaging agents.
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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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Qiao H, Zhang Y, Wu Z, Zhu L, Choi SR, Ploessl K, Kung HF. One-step preparation of [(18)F]FPBM for PET imaging of serotonin transporter (SERT) in the brain. Nucl Med Biol 2016; 43:470-7. [PMID: 27236282 DOI: 10.1016/j.nucmedbio.2016.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/16/2016] [Accepted: 04/14/2016] [Indexed: 01/27/2023]
Abstract
Serotonin transporters (SERT) in the brain play an important role in normal brain function. Selective serotonin reuptake inhibitors such as fluoxetine, sertraline, paroxetine, escitalopram, etc., specifically target SERT binding in the brain. Development of SERT imaging agents may be useful for studying the function of SERT by in vivo imaging. A one-step preparation of [(18)F]FPBM, 2-(2'-(dimethylamino)methyl)-4'-(3-([(18)F]fluoropropoxy)phenylthio)benzenamine, for positron emission tomography (PET) imaging of SERT binding in the brain was achieved. An active OTs intermediate, 9, was reacted with [(18)F]F(-)/K222 to produce [(18)F]FPBM in one step and in high radiochemical yield. This labeling reaction was evaluated and optimized under different temperatures, bases, solvents, and varying amounts of precursor 9. The radiolabeling reaction led to the desired [(18)F]FPBM in one step and the crude product was purified by HPLC purification to give no-carrier-added [(18)F]FPBM (radiochemical yield, 24-33%, decay corrected; radiochemical purity >99%). PET imaging studies in normal monkeys (n=4) showed fast, pronounced uptakes in the midbrain and thalamus, regions known to be rich in SERT binding sites. A displacement experiment with escitalopram (5mg/kg iv injection at 30min after [(18)F]FPBM injection) showed a rapid and complete reversal of SERT binding, suggesting that binding by [(18)F]FPBM was highly specific and reversible. A one-step radiolabeling method coupled with HPLC purification for preparation of [(18)F]FPBM was developed. Imaging studies suggest that it is feasible to use this method to prepare [(18)F]FPBM for in vivo PET imaging of SERT binding in the brain.
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Affiliation(s)
- Hongwen Qiao
- Department of Neurobiology, Xuanwu Hospital of Capital Medical University, Beijing 100053, China; Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yan Zhang
- Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing, 100875, China
| | - Zehui Wu
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lin Zhu
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China; Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing, 100875, China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Seok Rye Choi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Karl Ploessl
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hank F Kung
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Huang YY, Cheng CY, Huang WS, Ma KH, Tseng TW, Chou TK, Huang Y, Shiue CY. Toxicity and radiation dosimetry studies of the serotonin transporter radioligand [(18) F]AFM in rats and monkeys. EJNMMI Res 2015; 4:71. [PMID: 26116128 PMCID: PMC4452647 DOI: 10.1186/s13550-014-0071-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 11/27/2014] [Indexed: 11/12/2022] Open
Abstract
Background [18 F]AFM is a potent and promising PET imaging agent for the serotonin transporter. We carried out an acute toxicity study in rats and radiation dosimetry in monkeys before the translation of the tracer to humans. Methods Single- and multiple-dose toxicity studies were conducted in Sprague–Dawley rats. Male and female rats were injected intravenously with AFM tartrate as a single dose of 98.7 or 987 μg/kg (592 or 5,920 μg/m2, 100× or 1,000× the proposed human dose of 8 μg, respectively) on day 1 or as five consecutive daily doses of 98.7 μg/kg/day (592 μg /m2/day, 100× human dose, total dose 493.5 μg/kg). PET/CT scans were performed in four Formosan rock monkeys (two males and two females, each monkey scanned twice) using a Siemens BIOGRAPH scanner. After injection of [18 F]AFM (88.5 ± 20.3 MBq), a low-dose CT scan and a series of eight whole-body PET scans in 3-D mode were performed. Time-activity data of source organs were used to calculate the residence times and estimate the absorbed radiation dose using the OLINDA/EXM software. Results In the rats, neither the single dose nor the five daily doses of AFM tartrate produced overt adverse effects clinically. In the monkeys, the radiation doses received by most organs ranged between 8.3 and 39.1 μGy/MBq. The osteogenic cells, red marrow, and lungs received the highest doses of 39.1, 35.4, and 35.1 μGy/MBq, respectively. The effective doses extrapolated to male and female adult humans were 18.0 and 18.3 μSv/MBq, respectively. Conclusions Toxicity studies in Sprague–Dawley rats and radiation dosimetry studies in Formosa rock monkeys suggest that [18 F]AFM is safe for use in human PET imaging studies. Trial registration IACUC-12-200.
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Affiliation(s)
- Ya-Yao Huang
- PET Center, Department of Nuclear Medicine, Tri-Service General Hospital, 325 Sec. 2, Cheng-Kung Road, Taipei, 114, Taiwan,
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9
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Hicks JW, Sadovski O, Parkes J, Houle S, Hay BA, Carter RL, Wilson AA, Vasdev N. Radiosynthesis and ex vivo evaluation of [18F]-(S)-3-(6-(3-fluoropropoxy)benzo[d]isoxazol-3-yl)-5-(methoxymethyl)oxazolidin-2-one for imaging MAO-B with PET. Bioorg Med Chem Lett 2015; 25:288-91. [DOI: 10.1016/j.bmcl.2014.11.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 11/17/2022]
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Zhu L, Li G, Choi SR, Plössl K, Chan P, Qiao H, Zha Z, Kung HF. An improved preparation of [18F]FPBM: A potential serotonin transporter (SERT) imaging agent. Nucl Med Biol 2013; 40:974-9. [DOI: 10.1016/j.nucmedbio.2013.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 08/04/2013] [Indexed: 10/26/2022]
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Stehouwer JS, Goodman MM. 11C and18F PET radioligands for the serotonin transporter (SERT). J Labelled Comp Radiopharm 2013; 56:114-9. [DOI: 10.1002/jlcr.3011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 10/29/2012] [Accepted: 11/20/2012] [Indexed: 01/03/2023]
Affiliation(s)
- Jeffrey S. Stehouwer
- Center for Systems Imaging, Department of Radiology and Imaging Sciences; Emory University; Atlanta; GA; USA
| | - Mark M. Goodman
- Center for Systems Imaging, Department of Radiology and Imaging Sciences; Emory University; Atlanta; GA; USA
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12
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Zheng P, Lieberman BP, Ploessl K, Lemoine L, Miller S, Kung HF. A new single-photon emission computed tomography (SPECT) imaging agent for serotonin transporters: [(125)I]Flip-IDAM, (2-((2-((dimethylamino)methyl)-4-iodophenyl)thio)phenyl)methanol. Bioorg Med Chem Lett 2013; 23:869-72. [PMID: 23265880 DOI: 10.1016/j.bmcl.2012.11.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/07/2012] [Accepted: 11/12/2012] [Indexed: 11/18/2022]
Abstract
New ligands for in vivo brain imaging of serotonin transporter (SERT) with single photon emission tomography (SPECT) were prepared and evaluated. An efficient synthesis and radiolabeling of a biphenylthiol, FLIP-IDAM, 4, was accomplished. The affinity of FLIP-IDAM was evaluated by an in vitro inhibitory binding assay using [(125)I]-IDAM as radioligand in rat brain tissue homogenates (K(i) = 0.03 nM). New [(125)I]Flip-IDAM exhibited excellent binding affinity to SERT binding sites with a high hypothalamus to cerebellum ratio of 4 at 30 min post iv injection. The faster in vivo kinetics for brain uptake and a rapid washout from non-specific regions provide excellent signal to noise ratio. This new agent, when labeled with (123)I, may be a useful imaging agent for mapping SERT binding sites in the human brain.
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Affiliation(s)
- Pinguan Zheng
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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13
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Huang WS, Huang SY, Ho PS, Ma KH, Huang YY, Yeh CB, Liu RS, Cheng CY, Shiue CY. PET imaging of the brain serotonin transporters (SERT) with N,N-dimethyl-2-(2-amino-4-[18F]fluorophenylthio)benzylamine (4-[18F]-ADAM) in humans: a preliminary study. Eur J Nucl Med Mol Imaging 2012; 40:115-24. [PMID: 23053324 DOI: 10.1007/s00259-012-2250-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 09/03/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE The aim of this study was to assess the feasibility of using 4-[(18)F]-ADAM as a brain SERT imaging agent in humans. METHODS Enrolled in the study were 19 healthy Taiwanese subjects (11 men, 8 women; age 33 ± 9 years). The PET data were semiquantitatively analyzed and expressed as specific uptake ratios (SUR) and distribution volume ratios (DVR) using the software package PMOD. The SUR and DVR of 4-[(18)F]-ADAM in the raphe nucleus (RN), midbrain (MB), thalamus (TH), striatum (STR) and prefrontal cortex (PFC) were determined using the cerebellum (CB) as the reference region. RESULTS 4-[(18)F]-ADAM bound to known SERT-rich regions in human brain. The order of the regional brain uptake was MB (RN) > TH > STR > PFC > CB. The DVR (n = 4, t* = 60 min) in the RN, TH, STR and PFC were 3.00 ± 0.50, 2.25 ± 0.45, 2.05 ± 0.31 and 1.40 ± 0.13, respectively. The optimal time for imaging brain SERT with 4-[(18)F]-ADAM was 120-140 min after injection. At the optimal imaging time, the SURs (n = 15) in the MB, TH, STR, and PFC were 2.25 ± 0.20, 2.28 ± 0.20, 2.12 ± 0.18 and 1.47 ± 0.14, respectively. There were no significant differences in SERT availability between men and women (p < 0.05). CONCLUSION The results of this study showed that 4-[(18)F]-ADAM was safe for human studies and its distribution in human brain appeared to correlate well with the known distribution of SERT in the human brain. In addition, it had high specific binding and a reasonable optimal time for imaging brain SERT in humans. Thus, 4-[(18)F]-ADAM may be feasible for assessing the status of brain SERT in humans.
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Affiliation(s)
- Wen-Sheng Huang
- Department of Nuclear Medicine, PET Center, Tri-Service General Hospital, 325 Sec. 2 Cheng-Kung Rd, Neihu, Taipei, Taiwan
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14
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Liu J, Zhu L, Plössl K, Lieberman BP, Kung HF. Synthesis and evaluation of novel N-fluoropyridyl derivatives of tropane as potential PET imaging agents for the dopamine transporter. Bioorg Med Chem Lett 2011; 21:2962-5. [PMID: 21458259 DOI: 10.1016/j.bmcl.2011.03.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 10/18/2022]
Abstract
A series of novel N-fluoropyridyl-containing tropane derivatives were synthesized and their binding affinities for the dopamine transporter (DAT), serotonin transporter (SERT) and norepinephrine (NET) were determined via competitive radioligand binding assays. Among these derivatives, compound 6d showed the highest binding affinity to DAT (K(i)=4.1 nM), and selectivity for DAT over SERT (5-fold) and NET (16-fold). Compound 6d was radiolabeled with Fluorine-18 in two steps. Regional brain distribution and ex vivo autoradiography studies of [(18)F]6d demonstrated that the ligand was selectively localized in the striatum region, where DAT binding sites are highly expressed. [(18)F]6d may be useful as a potential radioligand for imaging DATs with PET.
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Affiliation(s)
- Jingying Liu
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, Beijing 100875, PR China
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15
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Xi W, Tian M, Zhang H. Molecular imaging in neuroscience research with small-animal PET in rodents. Neurosci Res 2011; 70:133-43. [PMID: 21241748 DOI: 10.1016/j.neures.2010.12.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 12/21/2010] [Accepted: 12/24/2010] [Indexed: 10/18/2022]
Abstract
Cognitive neuroscience, which studies the biological basis of mental processes, widely uses neuroimaging technologies like functional magnetic resonance imaging and positron emission tomography (PET) to study the human brain. Small laboratory animals, like rodents, are commonly used in brain research and provide abundant models of human brain diseases. The development of high-resolution small-animal PET and various radiotracers together with sophisticated methods for analyzing functional brain imaging data have accelerated research on brain function and neurotransmitter release during behavioral tasks in rodents. In this review, we first summarize advances in the methodology of cognitive research brought about by the development of sophisticated methods for whole-brain imaging analysis and improvements in neuroimaging protocols. Then, we discuss basic mechanisms related to metabolic changes and the expression of neurotransmitters in various brain areas during task-induced neural activity. In particular, we discuss glucose metabolism imaging and brain receptor imaging for various receptor systems. Finally, we discuss the current status and future perspectives. Mechanisms of neurotransmitter expression will probably become an increasingly important field of study in the future, leading to more collaboration between investigators in fields such as computational and theoretical neuroscience.
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Affiliation(s)
- Wang Xi
- Department of Nuclear Medicine, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
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Stehouwer JS, Daniel LM, Chen P, Voll RJ, Williams L, Plott SJ, Votaw JR, Owens MJ, Howell L, Goodman MM. Synthesis, fluorine-18 radiolabeling, and biological evaluation of N-((E)-4-fluorobut-2-en-1-yl)-2beta-carbomethoxy-3beta-(4'-halophenyl)nortropanes: candidate radioligands for in vivo imaging of the brain dopamine transporter with positron emission tomography. J Med Chem 2010; 53:5549-57. [PMID: 20597489 DOI: 10.1021/jm100269c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N-(E)-fluorobutenyl-3beta-(para-halo-phenyl)nortropanes 9-12 were synthesized as ligands of the dopamine transporter (DAT) for use as (18)F-labeled positron emission tomography (PET) imaging agents. In vitro competition binding assays demonstrated that compounds 9-12 have a high affinity for the DAT and are selective for the DAT compared to the serotonin and norepinephrine transporters. MicroPET imaging with [(18)F]9-[(18)F]11 in anesthetized cynomolgus monkeys showed high uptake in the putamen with lesser uptake in the caudate, but significant washout of the radiotracer was only observed for [(18)F]9. PET imaging with [(18)F]9 in an awake rhesus monkey showed high and nearly equal uptake in both the putamen and caudate with peak uptake achieved after 20 min followed by a leveling-off for about 10 min and then a steady washout and attainment of a quasi-equilibrium. During the time period 40-80 min postinjection of [(18)F]9, the ratio of uptake in the putamen and caudate vs cerebellum uptake was > or = 4.
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Wang JL, Oya S, Parhi AK, Lieberman BP, Ploessl K, Hou C, Kung HF. In vivo studies of the SERT-selective [18F]FPBM and VMAT2-selective [18F]AV-133 radiotracers in a rat model of Parkinson's disease. Nucl Med Biol 2010; 37:479-86. [PMID: 20447560 DOI: 10.1016/j.nucmedbio.2010.01.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 01/14/2010] [Accepted: 01/27/2010] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The utility of [(18)F]FPBM [2-(2'-((dimethylamino)methyl)-4'-(3-[(18)F]-fluoropropoxy)phenylthio)benzenamine], a selective serotonin transporter (SERT) tracer, and [(18)F]AV-133 [(+)-2-Hydroxy-3-isobutyl-9-(3-fluoropropoxy)-10-methoxy-1,2,3,4,6,7-hexahydro-11bH-benzo[a]quinolizine], a selective vesicular monoamine transporter 2 (VMAT2) tracer, were tested in the 6-hydroxydopamine (6-OHDA) unilateral lesioned rat model. METHODS Positron emission tomography (PET) imaging of three 6-OHDA unilateral lesioned male Sprague Dawley rats (Rats 1-3) were performed with [(18)F]FPBM and [(18)F]AV-133 to examine whether changes in SERT and VMAT2 binding, respectively, could be detected in the brain. The brains of the three rats were then removed and examined by in vitro autoradiography with [(18)F]FPBM and the dopamine transporter ligand, [(125)I]IPT [N-(3'-[(125)I]-iodopropen-2'-yl)-2-beta-carbomethoxy-3-beta-(4-chloro phenyl) tropane, for confirmation. Biodistribution of [(18)F]FPBM in a separate group of p-chloroamphetamine (PCA) treated rats were also performed. RESULTS PET image analysis showed varying levels of SERT binding reduction (Rat 1=-11%, Rat 2=-4%, Rat 3=-43%; n=2) and a clear and definitive loss of VMAT2 binding (Rat 1=-87%, Rat 2=-72%, and Rat 3=-91%; n=1) in the left striatum when compared to the right (non-lesioned side) striatum. The results from PET imaging were corroborated with quantitative in vitro autoradiography. Rats treated with a selective serotonin toxin (p-chloroamphetamine) showed a significant reduction of [(18)F]FPBM uptake in the cortex and hypothalamus regions of the brain. CONCLUSION The preliminary data suggest that [(18)F]FPBM and [(18)F]AV-133 may be useful for the examination of serotonergic and dopaminergic neuron integrity, respectively, in the living brain.
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Affiliation(s)
- Julie L Wang
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Wang JL, Deutsch EC, Oya S, Kung HF. FlipADAM: a potential new SPECT imaging agent for the serotonin transporter. Nucl Med Biol 2010; 37:577-86. [DOI: 10.1016/j.nucmedbio.2010.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 02/09/2010] [Accepted: 02/27/2010] [Indexed: 10/19/2022]
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Huang YY, Ma KH, Tseng TW, Chou TK, Ng H, Mirsalis JC, Fu YK, Chu TC, Huang WS, Shiue CY. Biodistribution, toxicity and radiation dosimetry studies of the serotonin transporter radioligand 4-[18F]-ADAM in rats and monkeys. Eur J Nucl Med Mol Imaging 2009; 37:545-55. [PMID: 19820930 DOI: 10.1007/s00259-009-1281-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 09/04/2009] [Indexed: 11/24/2022]
Abstract
PURPOSE 4-[(18)F]-ADAM is a potent serotonin transport imaging agent. We studied its toxicity in rats and radiation dosimetry in monkeys before human studies are undertaken. METHODS Single and multiple-dosage toxicity studies were conducted in Sprague-Dawley rats. Male and female rats were injected intravenously with 4-F-ADAM as a single dose of 1,023.7 microg/kg (1,000 times the human dose) or as five consecutive daily doses of 102.37 microg/kg (100 times the human dose). PET/CT scans were performed in seven Formosa Rock monkeys (four males and three females) using a Siemens Biograph scanner. After injection of 4-[(18)F]-ADAM (182+/-8 MBq), a low dose CT scan and a series of eight whole-body PET scans were performed. Whole-body images were acquired in 3-D mode. Time-activity data of source organs were used to calculate the residence times and estimate the absorbed radiation dose using OLINDA/EXM software. RESULTS In the rats neither the single dose nor the five daily doses of 4-F-ADAM produced overt adverse effects clinically. In the monkeys the radiation doses received by most organs ranged between 7.1 and 35.7 microGy/MBq, and the urinary bladder was considered to be the critical organ. The effective doses extrapolated to male and female adult humans were 17.4 and 21.8 microSv/MBq, respectively. CONCLUSION Toxicity studies in Sprague-Dawley rats and radiation dosimetry studies in Formosa Rock monkeys suggested that 4-[(18)F]-ADAM is safe for use in human PET imaging studies.
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Affiliation(s)
- Ya-Yao Huang
- PET Center, Department of Nuclear Medicine, Tri-Service General Hospital, 325 Sec. 2, Cheng-Kung Rd., Neihu 114, Taipei, Taiwan
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Wang JL, Parhi AK, Oya S, Lieberman B, Kung HF. In Vivo Characterization of a Series of 18F-Diaryl Sulfides (18F-2-(2′-((Dimethylamino)Methyl)-4′-(Fluoroalkoxy)Phenylthio)Benzenamine) for PET Imaging of the Serotonin Transporter. J Nucl Med 2009; 50:1509-17. [DOI: 10.2967/jnumed.108.060723] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Ma KH, Huang WS, Kuo YY, Peng CJ, Liou NH, Liu RS, Hwang JJ, Liu JC, Chen HJ, Shiue CY. Validation of 4-[18F]-ADAM as a SERT imaging agent using micro-PET and autoradiography. Neuroimage 2009; 45:687-93. [DOI: 10.1016/j.neuroimage.2008.12.060] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 12/04/2008] [Accepted: 12/23/2008] [Indexed: 11/24/2022] Open
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Huang YY, Huang WS, Chu TC, Shiue CY. An improved synthesis of 4-[18F]-ADAM, a potent serotonin transporter imaging agent. Appl Radiat Isot 2009; 67:1063-7. [PMID: 19339192 DOI: 10.1016/j.apradiso.2009.02.090] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/24/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
Abstract
An improved synthesis of N,N-dimethyl-2-(2-amino-4-[(18)F]fluorophenylthio)benzylamine (4-[(18)F]-ADAM, 2) as a potent serotonin transporter (SERT) imaging agent is described. Molecular orbital (MO) calculation predicts that N,N-dimethyl-2-(2-nitro-4-trimethylammoniumtrifluoromethanesulfonylphenylthio)benzamide (8) is probably a better precursor than N,N-dimethyl-2-(2,4-dinitrophenylthio)benzylamine (1) for preparing 2. Radioligand 2 was synthesized by the reaction of either precursor 1 or precursor 8 with K[(18)F]/K(2.2.2) at 120 degrees C followed by reduction with BH(3) at 80 degrees C. The radiochemical yield (EOB) of 2 synthesized from precursor 1 and 8 was 5.7+/-2.4% (n=6) and 14.8+/-4.0% (n=5), respectively, in a synthesis time of 120 min from EOB. The specific activity of 2 was 3 Ci/micromol or 111 GBq/micromol (EOB). Thus, this new synthetic method has significantly improved the radiochemical yield of 4-[(18)F]-ADAM and makes this radioligand more accessible to PET Centers without a cyclotron.
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Affiliation(s)
- Ya-Yao Huang
- PET Center, Department of Nuclear Medicine, Tri-Service General Hospital 325 Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan
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Stehouwer JS, Jarkas N, Zeng F, Voll RJ, Williams L, Camp VM, Malveaux EJ, Votaw JR, Howell L, J.Owens M, Goodman MM. Synthesis, radiosynthesis, and biological evaluation of fluorine-18-labeled 2beta-carbo(fluoroalkoxy)-3beta-(3'-((Z)-2-haloethenyl)phenyl)nortropanes: candidate radioligands for in vivo imaging of the serotonin transporter with positron emission tomography. J Med Chem 2008; 51:7788-99. [PMID: 19053782 PMCID: PMC2668213 DOI: 10.1021/jm800781a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The meta-vinylhalide fluoroalkyl ester nortropanes 1-4 were synthesized as ligands of the serotonin transporter (SERT) for use as positron emission tomography (PET) imaging agents. In vitro competition binding assays demonstrated that 1-4 have a high affinity for the SERT (K(i) values = 0.3-0.4 nM) and are selective for the SERT over the dopamine and norepinephrine transporters (DAT and NET). MicroPET imaging in anesthetized cynomolgus monkeys with [(18)F]1-[(18)F]4 demonstrated that all four tracers behave similarly with peak uptake in the SERT-rich brain regions achieved after 45-55 min, followed by a steady washout. An awake monkey study was performed with [(18)F]1, which demonstrated that the uptake of [(18)F]1 was not influenced by anesthesia. Chase studies with the SERT ligand 15 displaced [(18)F]1-[(18)F]4, but chase studies with the DAT ligand 16 did not displace [(18)F]1-[(18)F]4 thus indicating that the tracers were binding specifically to the SERT.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Mark M. Goodman
- To whom correspondence should be addressed. Department of Radiology, Emory University, 1364 Clifton Road NE, Atlanta, GA 30322 Phone: (404) 727-9366. Fax: (404) 727-3488. E-mail:
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