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Wang J, Jin C, Zhou J, Zhou R, Tian M, Lee HJ, Zhang H. PET molecular imaging for pathophysiological visualization in Alzheimer's disease. Eur J Nucl Med Mol Imaging 2023; 50:765-783. [PMID: 36372804 PMCID: PMC9852140 DOI: 10.1007/s00259-022-05999-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/09/2022] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is the most common dementia worldwide. The exact etiology of AD is unclear as yet, and no effective treatments are currently available, making AD a tremendous burden posed on the whole society. As AD is a multifaceted and heterogeneous disease, and most biomarkers are dynamic in the course of AD, a range of biomarkers should be established to evaluate the severity and prognosis. Positron emission tomography (PET) offers a great opportunity to visualize AD from diverse perspectives by using radiolabeled agents involved in various pathophysiological processes; PET imaging technique helps to explore the pathomechanisms of AD comprehensively and find out the most appropriate biomarker in each AD phase, leading to a better evaluation of the disease. In this review, we discuss the application of PET in the course of AD and summarized radiolabeled compounds with favorable imaging characteristics.
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Affiliation(s)
- Jing Wang
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XInstitute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, 310009 Zhejiang China ,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009 Zhejiang China
| | - Chentao Jin
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China
| | - Jinyun Zhou
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China
| | - Rui Zhou
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China
| | - Mei Tian
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XInstitute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, 310009 Zhejiang China ,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009 Zhejiang China
| | - Hyeon Jeong Lee
- grid.13402.340000 0004 1759 700XCollege of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310014 Zhejiang China
| | - Hong Zhang
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XInstitute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, 310009 Zhejiang China ,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XCollege of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310014 Zhejiang China ,grid.13402.340000 0004 1759 700XKey Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, 310014 Zhejiang China
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Central Nervous System Trial Failures: Using the Fragile X Syndrome-mGluR5 Drug Target to Highlight the Complexities of Translating Preclinical Discoveries Into Human Trials. J Clin Psychopharmacol 2022; 42:234-237. [PMID: 35489028 PMCID: PMC9060375 DOI: 10.1097/jcp.0000000000001553] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE/BACKGROUND Drug trials of the central nervous system(CNS) have been plagued with uninformative failures, often because of the difficulties of knowing definitively whether dosing achieved was sufficient to modulate the intended CNS target at adequate concentrations to produce pharmacodynamic or dose-related changes in readouts of brain function. Key design elements can be introduced into early-stage trials to get at this issue. METHODS/PROCEDURES This commentary builds on a review of earlier clinical studies in Fragile X syndrome to explore the extent to which the chain of evidence is in place to allow for interpretation of the results as ruling in or out the utility of modulating one or another molecular target to treat this disorder. Recent and current biomarker studies in Fragile X syndrome occurring subsequent to the clinical studies are reviewed to see if they might address any chain of evidence gaps. FINDINGS/RESULTS Despite the strong preclinical basis for targeting molecular mechanisms, the lack of efficacy seen in clinical studies remains uninterpretable, with regard to ruling in or out the utility of targeting the mechanism in a clinical population, given the absence of studies, which address whether doses of administered drug impacted the targeted brain mechanism. IMPLICATIONS/CONCLUSIONS The value of pursuing clinical studies of compounds targeted to novel mechanisms in the absence of clinical pharmacological evidence of some anticipated mediating pharmacokinetic/pharmacodynamic signals is questionable. One or more biomarkers of a drug effect on brain function are needed to establish dose dependent CNS effects that allow one to interpret clinical results as ruling in or out a mechanism and providing a firm basis for continuing or not, as well as informing dose selection in any clinical efficacy trials. Initiatives to address this general need in pediatric psychopharmacology are highlighted.
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Zhou YP, Makaravage KJ, Brugarolas P. Radiolabeling with [ 11C]HCN for Positron emission tomography. Nucl Med Biol 2021; 102-103:56-86. [PMID: 34624831 PMCID: PMC8978408 DOI: 10.1016/j.nucmedbio.2021.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/20/2021] [Accepted: 09/20/2021] [Indexed: 12/22/2022]
Abstract
Hydrogen cyanide (HCN) is a versatile synthon for generating carbon‑carbon and carbon-heteroatom bonds. Unlike other one-carbon synthons (i.e., CO, CO2), HCN can function as a nucleophile (as in potassium cyanide, KCN) and an electrophile (as in cyanogen bromide, (CN)Br). The incorporation of the CN motif into organic molecules generates nitriles, hydantoins and (thio)cyanates, which can be converted to carboxylic acids, aldehydes, amides and amines. Such versatile chemistry is particularly attractive in PET radiochemistry where diverse bioactive small molecules incorporating carbon-11 in different positions need to be produced. The first examples of making [11C]HCN for radiolabeling date back to the 1960s. During the ensuing decades, [11C]cyanide labeling was popular for producing biologically important molecules including 11C-labeled α-amino acids, sugars and neurotransmitters. [11C]cyanation is now reemerging in many PET centers due to its versatility for making novel tracers. Here, we summarize the chemistry of [11C]HCN, review the methods to make [11C]HCN past and present, describe methods for labeling different types of molecules with [11C]HCN, and provide an overview of the reactions available to convert nitriles into other functional groups. Finally, we discuss some of the challenges and opportunities in [11C]HCN labeling such as developing more robust methods to produce [11C]HCN and developing rapid and selective methods to convert nitriles into other functional groups in complex molecules.
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Affiliation(s)
- Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Katarina J Makaravage
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.
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Khan N, Laudermilk L, Ware J, Rosa T, Mathews K, Gay E, Amato G, Maitra R. Peripherally Selective CB1 Receptor Antagonist Improves Symptoms of Metabolic Syndrome in Mice. ACS Pharmacol Transl Sci 2021; 4:757-764. [PMID: 33860199 DOI: 10.1021/acsptsci.0c00213] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Indexed: 12/11/2022]
Abstract
Metabolic syndrome (MetS) is a complex disorder that stems from the additive effects of multiple underlying causes such as obesity, insulin resistance, and chronic low-grade inflammation. The endocannabinoid system plays a central role in appetite regulation, energy balance, lipid metabolism, insulin sensitivity, and β-cell function. The type 1 cannabinoid receptor (CB1R) antagonist SR141716A (rimonabant) showed promising antiobesity effects, but its use was discontinued due to adverse psychiatric events in some users. These adverse effects are due to antagonism of CB1R in the central nervous system (CNS). As such, CNS-sparing CB1R antagonists are presently being developed for various indications. In this study, we report that a recently described compound, 3-{1-[8-(2-chlorophenyl)-9-(4-chlorophenyl)-9H-purin-6-yl]piperidin-4-yl}-1-[6-(difluoromethoxy)pyridin-3-yl]urea (RTI1092769), a pyrazole based weak inverse agonist/antagonist of CB1 with very limited brain exposure, improves MetS related complications. Treatment with RTI1092769 inhibited weight gain and improved glucose utilization in obese mice maintained on a high fat diet. Hepatic triglyceride content and steatosis significantly improved with treatment. These phenotypes were supported by improvement in several biomarkers associated with nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). These results reinforce the idea that CB1 antagonists with limited brain exposure should be pursued for MetS and other important indications.
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Affiliation(s)
- Nayaab Khan
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Lucas Laudermilk
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Jalen Ware
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Taylor Rosa
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Kelly Mathews
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Elaine Gay
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - George Amato
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Rangan Maitra
- Center for Drug Discovery, RTI International, Research Triangle Park, North Carolina 27709, United States
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Hou L, Rong J, Haider A, Ogasawara D, Varlow C, Schafroth MA, Mu L, Gan J, Xu H, Fowler CJ, Zhang MR, Vasdev N, Ametamey S, Cravatt BF, Wang L, Liang SH. Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development. J Med Chem 2020; 64:123-149. [PMID: 33379862 DOI: 10.1021/acs.jmedchem.0c01459] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endocannabinoid system (ECS) is involved in a wide range of biological functions and comprises cannabinoid receptors and enzymes responsible for endocannabinoid synthesis and degradation. Over the past 2 decades, significant advances toward developing drugs and positron emission tomography (PET) tracers targeting different components of the ECS have been made. Herein, we summarized the recent development of PET tracers for imaging cannabinoid receptors 1 (CB1R) and 2 (CB2R) as well as the key enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), particularly focusing on PET neuroimaging applications. State-of-the-art PET tracers for the ECS will be reviewed including their chemical design, pharmacological properties, radiolabeling, as well as preclinical and human PET imaging. In addition, this review addresses the current challenges for ECS PET biomarker development and highlights the important role of PET ligands to study disease pathophysiology as well as to facilitate drug discovery.
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Affiliation(s)
- Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Daisuke Ogasawara
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Cassis Varlow
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Michael A Schafroth
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Linjing Mu
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Jiefeng Gan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States.,Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Simon Ametamey
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China.,Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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Miederer I, Wiegand V, Bausbacher N, Leukel P, Maus S, Hoffmann MA, Lutz B, Schreckenberger M. Quantification of the Cannabinoid Type 1 Receptor Availability in the Mouse Brain. Front Neuroanat 2020; 14:593793. [PMID: 33328905 PMCID: PMC7714830 DOI: 10.3389/fnana.2020.593793] [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] [Received: 08/11/2020] [Accepted: 11/03/2020] [Indexed: 11/13/2022] Open
Abstract
Introduction: The endocannabinoid system is involved in several diseases such as addictive disorders, schizophrenia, post-traumatic stress disorder, and eating disorders. As often mice are used as the preferred animal model in translational research, in particular when using genetically modified mice, this study aimed to provide a systematic analysis of in vivo cannabinoid type 1 (CB1) receptor ligand-binding capacity using positron emission tomography (PET) using the ligand [18F]MK-9470. We then compared the PET results with literature data from immunohistochemistry (IHC) to review the consistency between ex vivo protein expression and in vivo ligand binding. Methods: Six male C57BL/6J (6–9 weeks) mice were examined with the CB1 receptor ligand [18F]MK-9470 and small animal PET. Different brain regions were evaluated using the parameter %ID/ml. The PET results of the [18F]MK-9470 accumulation in the mouse brain were compared with immunohistochemical literature data. Results: The ligand [18F]MK-9470 was taken up into the mouse brain within 5 min after injection and exhibited slow kinetics. It accumulated highly in most parts of the brain. PET and IHC classifications were consistent for most parts of the telencephalon, while brain regions of the diencephalon, mesencephalon, and rhombencephalon were rated higher with PET than IHC. Conclusions: This preclinical [18F]MK-9470 study demonstrated the radioligand’s applicability for imaging the region-specific CB1 receptor availability in the healthy adult mouse brain and thus offers the potential to study CB1 receptor availability in pathological conditions.
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Affiliation(s)
- Isabelle Miederer
- Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Viktoria Wiegand
- Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nicole Bausbacher
- Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Petra Leukel
- Institute of Neuropathology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stephan Maus
- Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Manuela A Hoffmann
- Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.,Department of Occupational Health and Safety, Federal Ministry of Defense, Bonn, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.,Leibniz Institute for Resilience Research, Mainz, Germany
| | - Mathias Schreckenberger
- Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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7
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Godlewski G, Cinar R, Coffey NJ, Liu J, Jourdan T, Mukhopadhyay B, Chedester L, Liu Z, Osei-Hyiaman D, Iyer MR, Park JK, Smith RG, Iwakura H, Kunos G. Targeting Peripheral CB 1 Receptors Reduces Ethanol Intake via a Gut-Brain Axis. Cell Metab 2019; 29:1320-1333.e8. [PMID: 31105045 PMCID: PMC6551287 DOI: 10.1016/j.cmet.2019.04.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 03/01/2019] [Accepted: 04/21/2019] [Indexed: 12/21/2022]
Abstract
Endocannabinoids acting on the cannabinoid-1 receptor (CB1R) or ghrelin acting on its receptor (GHS-R1A) both promote alcohol-seeking behavior, but an interaction between the two signaling systems has not been explored. Here, we report that the peripheral CB1R inverse agonist JD5037 reduces ethanol drinking in wild-type mice but not in mice lacking CB1R, ghrelin peptide or GHS-R1A. JD5037 treatment of alcohol-drinking mice inhibits the formation of biologically active octanoyl-ghrelin without affecting its inactive precursor desacyl-ghrelin. In ghrelin-producing stomach cells, JD5037 reduced the level of the substrate octanoyl-carnitine generated from palmitoyl-carnitine by increasing fatty acid β-oxidation. Blocking gastric vagal afferents abrogated the ability of either CB1R or GHS-R1A blockade to reduce ethanol drinking. We conclude that blocking CB1R in ghrelin-producing cells reduces alcohol drinking by inhibiting the formation of active ghrelin and its signaling via gastric vagal afferents. Thus, peripheral CB1R blockade may have therapeutic potential in the treatment of alcoholism.
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Affiliation(s)
- Grzegorz Godlewski
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nathan J Coffey
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jie Liu
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tony Jourdan
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bani Mukhopadhyay
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lee Chedester
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ziyi Liu
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Douglas Osei-Hyiaman
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Malliga R Iyer
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joshua K Park
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Roy G Smith
- Scripps Research Institute, Jupiter, FL 33458, USA
| | - Hiroshi Iwakura
- Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
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Stadulytė A, Alcaide-Corral CJ, Walton T, Lucatelli C, Tavares AAS. Analysis of PK11195 concentrations in rodent whole blood and tissue samples by rapid and reproducible chromatographic method to support target-occupancy PET studies. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1118-1119:33-39. [PMID: 31005772 PMCID: PMC6522057 DOI: 10.1016/j.jchromb.2019.04.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 04/05/2019] [Accepted: 04/11/2019] [Indexed: 12/24/2022]
Abstract
In Positron Emission Tomography (PET) research, it is important to assess not only pharmacokinetics of a radiotracer in vivo, but also of the drugs used in blocking/displacement PET studies. Typically, pharmacokinetic/pharmacodynamic (PK/PD) analyses of drugs used in rodent PET studies are based on population average pharmacokinetic profiles of the drugs due to limited blood volume withdrawal while simultaneously maintaining physiological homeostasis. This likely results in bias of PET data quantification, including unknown bias of target occupancy (TO) measurements. This study aimed to develop a High Performance Liquid Chromatography (HPLC) method for PK/PD quantification of drugs used in preclinical rodent PET research, specifically the translocator 18 kDa protein (TSPO) selective drug, PK11195, that used sub-millilitre blood volumes. The lowest detection limit for the proposed HPLC method ranged between 7.5 and 10 ng/mL depending on the method used to calculate the limit of detection, and the measured average relative standard deviation for intermediate precision was equal to 17.2%. Most importantly, we were able to demonstrate a significant difference between calculated PK11195 concentrations at 0.5, 1, 2, 3, 5, 15 and 30 min post-administration and individually measured whole blood levels (significance level range from p < 0.05 to p < 0.001; one-way ANOVA, Dunnet's post hoc test, p < 0.05). The HPLC method developed here uses sub-millilitre sample volumes to reproducibly assess PK/PD of PK11195 in rodent blood. This study highlights the importance of individually measured PK/PD drug concentrations when quantifying the TO from blocking/displacement rodent PET experiments.
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Affiliation(s)
- Agnė Stadulytė
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Preclinical Imaging (EPI), University of Edinburgh, UK.
| | - Carlos José Alcaide-Corral
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Preclinical Imaging (EPI), University of Edinburgh, UK
| | - Tashfeen Walton
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, UK
| | - Christophe Lucatelli
- Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, UK
| | - Adriana Alexandre S Tavares
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Preclinical Imaging (EPI), University of Edinburgh, UK
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9
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Takai N, Miyajima N, Tonomura M, Abe K. Relationship between receptor occupancy and the antinociceptive effect of mu opioid receptor agonists in male rats. Brain Res 2017; 1680:105-109. [PMID: 29269051 DOI: 10.1016/j.brainres.2017.12.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 11/13/2017] [Accepted: 12/12/2017] [Indexed: 11/24/2022]
Abstract
The analgesic mechanisms of mu opioid receptor (MOR) agonists, including receptor occupancy at the site of action, are not completely understood. The aims of the present study were to evaluate: (i) receptor occupancy in the rat brain after administration of MOR agonists; (ii) the relationship between occupancy and the antinociceptive effect. Morphine (2 or 4 mg/kg) or oxycodone (1 or 3 mg/kg) was subcutaneously administered to rats. The antinociceptive effect of these drugs was measured by the hot-plate test. MOR occupancy in the thalamus was assessed by conducting an ex vivo receptor binding assay using [3H] [D-Ala2, N-MePhe4, Gly-ol]-enkephalin, followed by autoradiographic analysis. Both drugs produced antinociception in a dose-dependent manner, and these effects disappeared after the time point at which the maximal effect was elicited. Thalamic MOR occupancy was observed in a dose-dependent manner at the time point at which maximal antinociception was elicited, and relatively low occupancy was observed when the antinociceptive effect was decreasing. Good correlation between thalamic MOR occupancy and the antinociceptive effect was observed. These findings provide direct evidence for the receptor occupancy of MOR agonists at the site of action and its relationship with the analgesic effect.
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Affiliation(s)
- Nozomi Takai
- Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, Japan.
| | | | - Misato Tonomura
- Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, Japan.
| | - Kohji Abe
- Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, Japan.
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10
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Hong J, Lu S, Xu R, Liow JS, Woock AE, Jenko KJ, Gladding RL, Zoghbi SS, Innis RB, Pike VW. [carbonyl-11C]4-Fluoro-N-methyl-N-(4-(6-(methylamino)pyrimidin-4-yl)thiazol-2-yl)benzamide ([11C]FIMX) is an effective radioligand for PET imaging of metabotropic glutamate receptor 1 (mGluR1) in monkey brain. Nucl Med Biol 2015; 42:967-74. [PMID: 26320813 PMCID: PMC4658304 DOI: 10.1016/j.nucmedbio.2015.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/14/2015] [Accepted: 07/18/2015] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Metabotropic glutamate subtype receptor 1 (mGluR1) is implicated in several neuropsychiatric disorders and is a target for drug development. [(18)F]FIMX ([(18)F]4-fluoro--N-methyl-N--(4-(6-(methylamino)pyrimidin-4-yl)thiazol-2-yl)benzamide) is an effective radioligand for imaging brain mGluR1 with PET. A similarly effective radioligand with a shorter half-life would usefully allow PET studies of mGluR1 at baseline and after pharmacological or other challenge on the same day. Here we describe the preparation of [(11)C]FIMX for evaluation in monkey with PET. METHODS [(11)C]FIMX was prepared via Pd-promoted carbonylation of 1-fluoro-4-iodobenzene with [(11)C]carbon monoxide, aminolysis of the [(11)C]acyl-palladium complex with the requisite Boc-protected amine, and deprotection with HCl in THF. PET scans of [(11)C]FIMX injected into a monkey were performed at baseline and after preblock of mGluR1 with measurement of the arterial input function. RESULTS The radiosynthesis required 42 min and gave [(11)C]FIMX in about 5% overall decay-corrected radiochemical yield and with a specific activity of about 100 GBq/μmol. PET in rhesus monkey at baseline showed that radioactivity peaked high in receptor-rich cerebellum and much lower in receptor-poor occipital cortex. Radioactivity in cerebellum declined to 32% of peak at 85 min. VT at baseline appeared stable in all brain regions after 60 min. Under mGluR1 pre-blocked condition, radioactivity uptake in all regions declined more rapidly to a low level. Receptor pre-block reduced VT from 13.0 to 1.5 in cerebellum and from 2.9 to 1.4 in occipital cortex. CONCLUSION [(11)C]FIMX is an effective radioligand for imaging mGluR1 in monkey with PET.
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Affiliation(s)
- Jinsoo Hong
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Rong Xu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Alicia E Woock
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, 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, MD, 20892-1003, United States
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD, 20892-1003, United States.
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