1
|
Lopresti BJ, Stehouwer J, Reese AC, Mason NS, Royse SK, Narendran R, Laymon CM, Lopez OL, Cohen AD, Mathis CA, Villemagne VL. Kinetic modeling of the monoamine oxidase-B radioligand [ 18F]SMBT-1 in human brain with positron emission tomography. J Cereb Blood Flow Metab 2024:271678X241254679. [PMID: 38735059 DOI: 10.1177/0271678x241254679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
This paper describes pharmacokinetic analyses of the monoamine-oxidase-B (MAO-B) radiotracer [18F](S)-(2-methylpyrid-5-yl)-6-[(3-fluoro-2-hydroxy)propoxy]quinoline ([18F]SMBT-1) for positron emission tomography (PET) brain imaging. Brain MAO-B expression is widespread, predominantly within astrocytes. Reactive astrogliosis in response to neurodegenerative disease pathology is associated with MAO-B overexpression. Fourteen elderly subjects (8 control, 5 mild cognitive impairment, 1 Alzheimer's disease) with amyloid ([11C]PiB) and tau ([18F]flortaucipir) imaging assessments underwent dynamic [18F]SMBT-1 PET imaging with arterial input function determination. [18F]SMBT-1 showed high brain uptake and a retention pattern consistent with the known MAO-B distribution. A two-tissue compartment (2TC) model where the K1/k2 ratio was fixed to a whole brain value best described [18F]SMBT-1 kinetics. The 2TC total volume of distribution (VT) was well identified and highly correlated (r2∼0.8) with post-mortem MAO-B indices. Cerebellar grey matter (CGM) showed the lowest mean VT of any region and is considered the optimal pseudo-reference region. Simplified analysis methods including reference tissue models, non-compartmental models, and standard uptake value ratios (SUVR) agreed with 2TC outcomes (r2 > 0.9) but with varying bias. We found the CGM-normalized 70-90 min SUVR to be highly correlated (r2 = 0.93) with the 2TC distribution volume ratio (DVR) with acceptable bias (∼10%), representing a practical alternative for [18F]SMBT-1 analyses.
Collapse
Affiliation(s)
- Brian J Lopresti
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Jeffrey Stehouwer
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Alexandria C Reese
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Neale S Mason
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sarah K Royse
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rajesh Narendran
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Charles M Laymon
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Dept. of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Oscar L Lopez
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Clinical and Translational Sciences Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ann D Cohen
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Chester A Mathis
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Victor L Villemagne
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| |
Collapse
|
2
|
Gu F, Wu Q. Quantitation of dynamic total-body PET imaging: recent developments and future perspectives. Eur J Nucl Med Mol Imaging 2023; 50:3538-3557. [PMID: 37460750 PMCID: PMC10547641 DOI: 10.1007/s00259-023-06299-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 06/05/2023] [Indexed: 10/04/2023]
Abstract
BACKGROUND Positron emission tomography (PET) scanning is an important diagnostic imaging technique used in disease diagnosis, therapy planning, treatment monitoring, and medical research. The standardized uptake value (SUV) obtained at a single time frame has been widely employed in clinical practice. Well beyond this simple static measure, more detailed metabolic information can be recovered from dynamic PET scans, followed by the recovery of arterial input function and application of appropriate tracer kinetic models. Many efforts have been devoted to the development of quantitative techniques over the last couple of decades. CHALLENGES The advent of new-generation total-body PET scanners characterized by ultra-high sensitivity and long axial field of view, i.e., uEXPLORER (United Imaging Healthcare), PennPET Explorer (University of Pennsylvania), and Biograph Vision Quadra (Siemens Healthineers), further stimulates valuable inspiration to derive kinetics for multiple organs simultaneously. But some emerging issues also need to be addressed, e.g., the large-scale data size and organ-specific physiology. The direct implementation of classical methods for total-body PET imaging without proper validation may lead to less accurate results. CONCLUSIONS In this contribution, the published dynamic total-body PET datasets are outlined, and several challenges/opportunities for quantitation of such types of studies are presented. An overview of the basic equation, calculation of input function (based on blood sampling, image, population or mathematical model), and kinetic analysis encompassing parametric (compartmental model, graphical plot and spectral analysis) and non-parametric (B-spline and piece-wise basis elements) approaches is provided. The discussion mainly focuses on the feasibilities, recent developments, and future perspectives of these methodologies for a diverse-tissue environment.
Collapse
Affiliation(s)
- Fengyun Gu
- School of Mathematics and Physics, North China Electric Power University, 102206, Beijing, China.
- School of Mathematical Sciences, University College Cork, T12XF62, Cork, Ireland.
| | - Qi Wu
- School of Mathematical Sciences, University College Cork, T12XF62, Cork, Ireland
| |
Collapse
|
3
|
Fu H, Rong J, Chen Z, Zhou J, Collier T, Liang SH. Positron Emission Tomography (PET) Imaging Tracers for Serotonin Receptors. J Med Chem 2022; 65:10755-10808. [PMID: 35939391 DOI: 10.1021/acs.jmedchem.2c00633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) and 5-HT receptors (5-HTRs) have crucial roles in various neuropsychiatric disorders and neurodegenerative diseases, making them attractive diagnostic and therapeutic targets. Positron emission tomography (PET) is a noninvasive nuclear molecular imaging technique and is an essential tool in clinical diagnosis and drug discovery. In this context, numerous PET ligands have been developed for "visualizing" 5-HTRs in the brain and translated into human use to study disease mechanisms and/or support drug development. Herein, we present a comprehensive repertoire of 5-HTR PET ligands by focusing on their chemotypes and performance in PET imaging studies. Furthermore, this Perspective summarizes recent 5-HTR-focused drug discovery, including biased agonists and allosteric modulators, which would stimulate the development of more potent and subtype-selective 5-HTR PET ligands and thus further our understanding of 5-HTR biology.
Collapse
Affiliation(s)
- Hualong Fu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Zhen Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Jingyin Zhou
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Thomas Collier
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| |
Collapse
|
4
|
Willmann M, Hegger J, Neumaier B, Ermert J. Radiosynthesis and Biological Evaluation of [ 18F]R91150, a Selective 5-HT 2A Receptor Antagonist for PET-Imaging. ACS Med Chem Lett 2021; 12:738-744. [PMID: 34055220 DOI: 10.1021/acsmedchemlett.0c00658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/30/2021] [Indexed: 12/21/2022] Open
Abstract
Serotonergic 5-HT2A receptors in cortical and forebrain regions are an important substrate for the neuromodulatory actions of serotonin in the brain. They have been implicated in the etiology of many neuropsychiatric disorders and serve as a target for antipsychotic, antidepressant, and anxiolytic drugs. Positron emission tomography imaging using suitable radioligands can be applied for in vivo quantification of receptor densities and receptor occupancy for therapy evaluation. Recently, the radiosynthesis of the selective 5-HT2AR antagonist [18F]R91150 was reported. However, the six-step radiosynthesis is cumbersome and time-consuming with low radiochemical yields (RCYs) of <5%. In this work, [18F]R91150 was prepared using late-stage Cu-mediated radiofluorination to simplify its synthesis. The detailed protocol enabled us to obtain RCYs of 14 ± 1%, and the total synthesis time was reduced to 60 min. In addition, autoradiographic studies with [18F]R91150 in rat brain slices revealed the typical uptake pattern of 5-HT2A receptor ligands.
Collapse
Affiliation(s)
- Michael Willmann
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM-5, Nuclear Chemistry (INM-5), 52425 Jülich, Germany
| | - Julian Hegger
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM-5, Nuclear Chemistry (INM-5), 52425 Jülich, Germany
| | - Bernd Neumaier
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM-5, Nuclear Chemistry (INM-5), 52425 Jülich, Germany
- Uniklinik Köln, Institute of Radiochemistry and Experimental Molecular Imaging, 50937 Köln, Germany
| | - Johannes Ermert
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM-5, Nuclear Chemistry (INM-5), 52425 Jülich, Germany
| |
Collapse
|
5
|
Impact of DOTA Conjugation on Pharmacokinetics and Immunoreactivity of [ 177Lu]Lu-1C1m-Fc, an Anti TEM-1 Fusion Protein Antibody in a TEM-1 Positive Tumor Mouse Model. Pharmaceutics 2021; 13:pharmaceutics13010096. [PMID: 33451158 PMCID: PMC7828678 DOI: 10.3390/pharmaceutics13010096] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/30/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
1C1m-Fc, an anti-tumor endothelial marker 1 (TEM-1) scFv-Fc fusion protein antibody, was previously successfully radiolabeled with 177Lu. TEM-1 specific tumor uptake was observed together with a non-saturation dependent liver uptake that could be related to the number of dodecane tetraacetic acid (DOTA) chelator per 1C1m-Fc. The objective of this study was to verify this hypothesis and to find the best DOTA per 1C1m-Fc ratio for theranostic applications. 1C1m-Fc was conjugated with six concentrations of DOTA. High-pressure liquid chromatography, mass spectrometry, immunoreactivity assessment, and biodistribution studies in mice bearing TEM-1 positive tumors were performed. A multi-compartment pharmacokinetic model was used to fit the data and a global pharmacokinetic model was developed to illustrate the effect of liver capture and immunoreactivity loss. Organ absorbed doses in mice were calculated from biodistribution results. A loss of immunoreactivity was observed with the highest DOTA per 1C1m-Fc ratio. Except for the spleen and bone, an increase of DOTA per 1C1m-Fc ratio resulted in an increase of liver uptake and absorbed dose and a decrease of uptake in tumor and other tissues. Pharmacokinetic models correlated these results. The number of DOTA per antibody played a determining role in tumor targeting. One DOTA per 1C1m-Fc gave the best pharmacokinetic behavior for a future translation of [177Lu]Lu-1C1m-Fc in patients.
Collapse
|
6
|
Sridharan S, Raffel J, Nandoskar A, Record C, Brooks DJ, Owen D, Sharp D, Muraro PA, Gunn R, Nicholas R. Confirmation of Specific Binding of the 18-kDa Translocator Protein (TSPO) Radioligand [ 18F]GE-180: a Blocking Study Using XBD173 in Multiple Sclerosis Normal Appearing White and Grey Matter. Mol Imaging Biol 2020; 21:935-944. [PMID: 30796709 DOI: 10.1007/s11307-019-01323-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE Measurements of non-displaceable binding (VND) of positron emission tomography (PET) ligands are not often made in vivo in humans because they require ligands to displace binding to target receptors and there are few readily available, safe ones to use. A technique to measure VND for ligands for the 18-kDa translocator protein (TSPO) has recently been developed which compares the total volume of distribution (VT) before and after administration of the TSPO ligand XBD173. Here, we used XBD173 with an occupancy plot to quantify VND for two TSPO radiotracers, [18F]GE-180 and [11C]PBR28, in cohorts of people with multiple sclerosis (MS). Additionally, we compared plots of subjects carrying high (HAB) or mixed binding (MAB) affinity polymorphisms of TSPO to estimate VND without receptor blockade. PROCEDURES Twelve people with MS underwent baseline MRI and 90-min dynamic [18F]GE-180 PET or [11C]PBR28 PET (n = 6; three HAB, three MAB each). Arterial blood sampling was used to generate plasma input functions for the two-tissue compartment model. VND was calculated using two independent methods: the occupancy plot (by modelling the differences in signal post XBD173) and the polymorphism plot (by modelling the differences in signal across presence and absence of rs6971 genotypes). RESULTS Whole brain VT (mean ± standard deviation) was 0.29 ± 0.17 ml/cm3 for [18F]GE-180 and 5.01 ± 1.88 ml/cm3 for [11C]PBR28. Using the occupancy and polymorphism plots respectively, VND for [18F]GE-180 was 0.11 ml/cm3 (95 % CI = 0.02, 0.16) and 0.20 ml/cm3 (0.16, 0.34), accounting for, on average, 55 % of VT in the whole brain. For [11C]PBR28, these values were 3.81 ml/cm3 (3.02, 4.21) and 3.49 ml/cm3 (1.38, 4.27), accounting for 67 % of average whole brain VT. CONCLUSIONS Although VT for [18F]GE-180 is low, indicating low brain penetration, half the signal shown by MS subjects reflected specific TSPO binding. VT for [11C]PBR28 was higher and two thirds of the binding was non-specific. No brain ROIs were devoid of specific signal, further confirming that true reference tissue approaches are potentially problematic for estimating TSPO levels.
Collapse
Affiliation(s)
- Sujata Sridharan
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK.
| | - Joel Raffel
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| | - Ashwini Nandoskar
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| | - Chris Record
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| | - David J Brooks
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Institute of Neuroscience, Newcastle upon Tyne University, Newcastle upon Tyne, UK
| | - David Owen
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| | - David Sharp
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| | - Paolo A Muraro
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| | | | - Richard Nicholas
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK
| |
Collapse
|
7
|
Bhatt S, Nabulsi NB, Li S, Cai Z, Matuskey D, Bini J, Najafzadeh S, Kapinos M, Ropchan JR, Carson RE, Cosgrove KP, Huang Y, Hillmer AT. First in-human PET study and kinetic evaluation of [ 18F]AS2471907 for imaging 11β-hydroxysteroid dehydrogenase type 1. J Cereb Blood Flow Metab 2020; 40:695-704. [PMID: 30895878 PMCID: PMC7168798 DOI: 10.1177/0271678x19838633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 01/11/2023]
Abstract
11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes enzymatic conversion of cortisone into the stress hormone cortisol. This first-in-human brain imaging study characterizes the kinetic modeling and test-retest reproducibility of [18F]AS2471907, a novel PET radiotracer for 11β-HSD1. Eight individuals underwent one 180-min (n = 4) or two 240-min (n = 4) [18F]AS2471907 PET brain scans (12 total) acquired on the high-resolution research tomograph (HRRT) scanner with arterial blood sampling. Imaging data were modeled with 1-tissue (1T) and 2-tissue (2T) compartment models and with multilinear analysis (MA1) to estimate [18F]AS2471907 availability (VT). [18F]AS2471907 demonstrated high, heterogeneous uptake throughout the brain. Of the compartment models, 2T best described [18F]AS2471907 data. Estimates of VT were highly correlated between 2T and MA1 (t* = 30 min) with MA1 yielding VT values ranging from 3.2 ± 1.0 mL/cm3 in the caudate to 15.7 ± 4.2 mL/cm3 in the occipital cortex. The median absolute test-retest variability of 16 ± 5% and high intraclass correlation coefficient (ICC) values of 0.67-0.97 across regions indicate fair test-retest reliability but large intersubject variability. VT estimates using 180 min were within 10% of estimates using full acquisition time. In summary, [18F]AS2471907 exhibits reasonable kinetic properties for imaging 11β-HSD1 in human brain.
Collapse
Affiliation(s)
- Shivani Bhatt
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT, USA
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Nabeel B Nabulsi
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Songye Li
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Zhengxin Cai
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - David Matuskey
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Jason Bini
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Soheila Najafzadeh
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Michael Kapinos
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Jim R Ropchan
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Richard E Carson
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Kelly P Cosgrove
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT, USA
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- National Center for PTSD, West Haven VA Hospital, West Haven, CT, USA
| | - Yiyun Huang
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Ansel T Hillmer
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| |
Collapse
|
8
|
Pauwelyn G, Vlerick L, Dockx R, Verhoeven J, Dobbeleir A, Bosmans T, Peremans K, Vanhove C, Polis I, De Vos F. Kinetic analysis of [ 18F] altanserin bolus injection in the canine brain using PET imaging. BMC Vet Res 2019; 15:415. [PMID: 31752848 PMCID: PMC6873736 DOI: 10.1186/s12917-019-2165-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Currently, [18F] altanserin is the most frequently used PET-radioligand for serotonin2A (5-HT2A) receptor imaging in the human brain but has never been validated in dogs. In vivo imaging of this receptor in the canine brain could improve diagnosis and therapy of several behavioural disorders in dogs. Furthermore, since dogs are considered as a valuable animal model for human psychiatric disorders, the ability to image this receptor in dogs could help to increase our understanding of the pathophysiology of these diseases. Therefore, five healthy laboratory beagles underwent a 90-min dynamic PET scan with arterial blood sampling after [18F] altanserin bolus injection. Compartmental modelling using metabolite corrected arterial input functions was compared with reference tissue modelling with the cerebellum as reference region. RESULTS The distribution of [18F] altanserin in the canine brain corresponded well to the distribution of 5-HT2A receptors in human and rodent studies. The kinetics could be best described by a 2-Tissue compartment (2-TC) model. All reference tissue models were highly correlated with the 2-TC model, indicating compartmental modelling can be replaced by reference tissue models to avoid arterial blood sampling. CONCLUSIONS This study demonstrates that [18F] altanserin PET is a reliable tool to visualize and quantify the 5-HT2A receptor in the canine brain.
Collapse
Affiliation(s)
- Glenn Pauwelyn
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.
| | - Lise Vlerick
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Robrecht Dockx
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.,Department of Psychiatry and Medical Psychology, Ghent University, Ghent, Belgium
| | - Jeroen Verhoeven
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Andre Dobbeleir
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.,Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Tim Bosmans
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Kathelijne Peremans
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Christian Vanhove
- Institute Biomedical Technology - Medisip - Infinity, Ghent University, Ghent, Belgium
| | - Ingeborgh Polis
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Filip De Vos
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| |
Collapse
|
9
|
Characterization of the serotonin 2A receptor selective PET tracer (R)-[ 18F]MH.MZ in the human brain. Eur J Nucl Med Mol Imaging 2019; 47:355-365. [PMID: 31606832 DOI: 10.1007/s00259-019-04527-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/05/2019] [Indexed: 12/24/2022]
Abstract
PURPOSE The serotonin receptor subtype 2A antagonist (5-HT2AR) (R)-[18F]MH.MZ has in preclinical studies been identified as a promising PET imaging agent for quantification of cerebral 5-HT2ARs. It displays a very similar selectivity profile as [11C]MDL 100907, one of the most selective compounds identified thus far for the 5-HT2AR. As [11C]MDL 100907, (R)-[18F]MH.MZ also displays slow brain kinetics in various animal models; however, the half-life of fluorine-18 allows for long scan times and consequently, a more precise determination of 5-HT2AR binding could still be feasible. In this study, we aimed to evaluate the potential of (R)-[18F]MH.MZ PET to image and quantify the 5-HT2AR in the human brain in vivo. METHODS Nine healthy volunteers underwent (R)-[18F]MH.MZ PET at baseline and four out of these also received a second PET scan, after ketanserin pretreatment. Regional time-activity curves of 17 brain regions were analyzed before and after pretreatment. We also investigated radiometabolism, time-dependent stability of outcomes measures, specificity of (R)-[18F]MH.MZ 5-HT2AR binding, and performance of different kinetic modeling approaches. RESULTS Highest uptake was determined in 5-HT2AR rich regions with a BPND of approximately 1.5 in cortex regions. No radiometabolism was observed. 1TCM and 2TCM resulted in similar outcome measure, whereas reference tissue models resulted in a small, but predictable bias. (R)-[18F]MH.MZ binding conformed to the known distribution of 5-HT2AR and could be blocked by pretreatment with ketanserin. Moreover, outcomes measures were stable after 100-110 min. CONCLUSION (R)-[18F]MH.MZ is a suitable PET tracer to image and quantify the 5-HT2AR system in humans. In comparison with [11C]MDL 100907, faster and more precise outcome measure could be obtained using (R)-[18F]MH.MZ. We believe that (R)-[18F]MH.MZ has the potential to become the antagonist radiotracer of choice to investigate the human 5-HT2AR system.
Collapse
|
10
|
Pauwelyn G, Vlerick L, Dockx R, Verhoeven J, Dobbeleir A, Peremans K, Goethals I, Bosmans T, Vanhove C, De Vos F, Polis I. PET quantification of [18F]MPPF in the canine brain using blood input and reference tissue modelling. PLoS One 2019; 14:e0218237. [PMID: 31185062 PMCID: PMC6559658 DOI: 10.1371/journal.pone.0218237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 05/30/2019] [Indexed: 12/04/2022] Open
Abstract
Numerous studies have shown that the serotonin1A (5-HT1A) receptor is implicated in the pathophysiology and treatment of several psychiatric and neurological disorders. Furthermore, functional imaging studies in a variety of species have demonstrated that 4-(2´-Methoxyphenyl)-1-[2´-(N-2´´-pyridinyl)-p- [18F]fluorobenzamidoethylpiperazine ([18F]MPPF) is a valid and useful PET tracer to visualize the 5HT1A receptor. However, to our knowledge, [18F]MPPF has never been demonstrated in the canine brain. The ability to image the 5HT1A receptor with PET in dogs could improve diagnosis and therapy in both canine and human behavioural and neuropsychiatric disorders. To examine the potential use of [18F]MPPF in dogs, five healthy adult laboratory beagles underwent a 60-minutes dynamic PET scan with [18F]MPPF while arterial blood samples were taken. For each region of interest, total distribution volume (VT) and corresponding binding potential (BPND) were calculated using the 1-tissue compartment model (1-TC), 2-Tissue compartment model (2-TC) and Logan plot. The preferred model was chosen based on the goodness-of-fit, calculated with the Akaike information criterium (AIC). Subsequently, the BPND values of the preferred compartment model were compared with the estimated BPND values using three reference tissue models (RTMs): the 2-step simplified reference tissue model (SRTM2), the 2-parameter multilinear reference tissue model (MRTM2) and the Logan reference tissue model. According to the lower AIC values of the 2-TC model compared to the 1-TC in all ROIs, the 2-TC model showed a better fit. Calculating BPND using reference tissue modelling demonstrated high correlation with the BPND obtained by metabolite corrected plasma input 2-TC. This first-in-dog study indicates the results of a bolus injection with [18F]MPPF in dogs are consistent with the observations presented in the literature for other animal species and humans. Furthermore, for future experiments, compartmental modelling using invasive blood sampling could be replaced by RTMs, using the cerebellum as reference region.
Collapse
Affiliation(s)
- Glenn Pauwelyn
- Laboratory of Radiopharmacy, Ghent University, Ghent, Belgium
| | - Lise Vlerick
- Small Animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Robrecht Dockx
- Small Animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Department of Psychiatry and Medical Psychology, Ghent University, Ghent, Belgium
| | | | - Andre Dobbeleir
- Small Animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Kathelijne Peremans
- Small Animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Ingeborg Goethals
- Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Tim Bosmans
- Small Animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Christian Vanhove
- Institute Biomedical Technology–Medisip–Infinity, Ghent University, Ghent, Belgium
| | - Filip De Vos
- Laboratory of Radiopharmacy, Ghent University, Ghent, Belgium
| | - Ingeborgh Polis
- Small Animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| |
Collapse
|
11
|
Prabhakaran J, DeLorenzo C, Zanderigo F, Knudsen GM, Gilling N, Pratap M, Jorgensen MJ, Daunais J, Kaplan JR, Parsey RV, Mann JJ, Kumar D. In vivo PET Imaging of [11C]CIMBI-5, a 5-HT2AR Agonist Radiotracer in Nonhuman Primates. JOURNAL OF PHARMACY & PHARMACEUTICAL SCIENCES : A PUBLICATION OF THE CANADIAN SOCIETY FOR PHARMACEUTICAL SCIENCES, SOCIETE CANADIENNE DES SCIENCES PHARMACEUTIQUES 2019; 22:352-364. [PMID: 31356761 PMCID: PMC7453972 DOI: 10.18433/jpps30329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE 5-HT2AR exists in high and low affinity states. Agonist PET tracers measure binding to the active high affinity site and thus provide a functionally relevant measure of the receptor. Limited in vivo data have been reported so far for a comparison of agonist versus antagonist tracers for 5-HT2AR used as a proof of principle for measurement of high and low affinity states of this receptor. We compared the in vivo binding of [11C]CIMBI-5, a 5-HT2AR agonist, and of the antagonist [11C]M100907, in monkeys and baboons. METHODS [11C]CIMBI-5 and [11C]M100907 baseline PET scans were performed in anesthetized male baboons (n=2) and male vervet monkeys (n=2) with an ECAT EXACT HR+ and GE 64-slice PET/CT Discovery VCT scanners. Blocking studies were performed in vervet monkeys by pretreatment with MDL100907 (0.5 mg/kg, i.v.) 60 minutes prior to the scan. Regional distribution volumes and binding potentials were calculated for each ROI using the likelihood estimation in graphical analysis and Logan plot, with either plasma input function or reference region as input, and simplified reference tissue model approaches. RESULTS PET imaging of [11C]CIMBI-5 in baboons and monkeys showed the highest binding in 5-HT2AR-rich cortical regions, while the lowest binding was observed in cerebellum, consistent with the expected distribution of 5-HT2AR. Very low free fractions and rapid metabolism were observed for [11C]CIMBI-5 in baboon plasma. Binding potential values for [11C]CIMBI-5 were 25-33% lower than those for [11C]MDL100907 in the considered brain regions. CONCLUSION The lower binding potential of [11C]CIMBI-5 in comparison to [11C]MDL100907 is likely due to the preferential binding of the former to the high affinity site in vivo in contrast to the antagonist, [11C]MDL100907, which binds to both high and low affinity sites.
Collapse
Affiliation(s)
- Jaya Prabhakaran
- Department of Psychiatry, Columbia University Medical Center, New York, USA. Area of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Cross-sectional and longitudinal small animal PET shows pre and post-synaptic striatal dopaminergic deficits in an animal model of HIV. Nucl Med Biol 2017; 55:27-33. [PMID: 29031113 DOI: 10.1016/j.nucmedbio.2017.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/01/2017] [Accepted: 08/23/2017] [Indexed: 11/20/2022]
Abstract
INTRODUCTION In vivo imaging biomarkers of various HIV neuropathologies, including dopaminergic dysfunction, are still lacking. Towards developing dopaminergic biomarkers of brain involvement in HIV, we assessed the pre and postsynaptic components of the dopaminergic system in the HIV-1 transgenic rat (Tg), a well-characterized model of treated HIV+ patients, using small-animal PET imaging. METHODS Fifteen to 18 month-old Tg and wild type (WT) rats were imaged with both [18F]-FP-CMT, a dopamine transporter (DAT) ligand (n=16), and [18F]-Fallypride, a D2/D3 dopamine receptor (D2/D3DR) ligand (n=16). Five to 8 month-old Tg and WT rats (n=18) were also imaged with [18F]-FP-CMT. A subset of animals was imaged longitudinally at 7 and 17 months of age. Multiplex immunohistochemistry staining for DAT, tyrosine hydroxylase, D2DR, D3DR, GFAP, Iba1 and NeuN was performed on a subgroup of the scanned animals. RESULTS [18F]-FP-CMT and [18F]-Fallypride binding potential (BPND) values were significantly lower in 15-18 month-old Tg compared to age-matched WT rats (p<0.0001 and 0.001, respectively). [18F]-FP-CMT BPND values in 5-8 month-old rats, however, were not significantly different. Longitudinal age-related decrease in [18F]-FP-CMT BPND was exacerbated in the Tg rat. Immunohistochemistry showed decreased staining of dopaminergic markers in Tg rats. Rats with higher serum gp120 had lower mean BPND values for both ligands. CONCLUSIONS We found presynaptic and postsynaptic dopaminergic dysfunction/loss in older Tg compared to WT rats. We believe this to be related to neurotoxicity of viral proteins present in the Tg rats' serum and brain. ADVANCES IN KNOWLEDGE Our findings confirm prior reports of neurobehavioral abnormalities suggestive of dopaminergic dysfunction in this model. They also suggest similarities between the Tg rat and HIV+ patients as far as dopaminergic dysfunction. IMPLICATIONS FOR PATIENT CARE The Tg rat, along with the above-described quantitative PET imaging biomarkers, can have a role in the evaluation of HIV neuroprotective therapies prior to human translation.
Collapse
|
13
|
Nahimi A, Sommerauer M, Kinnerup MB, Østergaard K, Wintherdahl M, Jacobsen J, Schacht A, Johnsen B, Damholdt MF, Borghammer P, Gjedde A. Noradrenergic Deficits in Parkinson Disease Imaged with 11C-MeNER. J Nucl Med 2017; 59:659-664. [DOI: 10.2967/jnumed.117.190975] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/18/2017] [Indexed: 01/08/2023] Open
|
14
|
Toyohara J, Sakata M, Hatano K, Yanai S, Endo S, Ishibashi K, Wagatsuma K, Ishii K, Ishiwata K. Preclinical and first-in-man studies of [(11)C]CB184 for imaging the 18-kDa translocator protein by positron emission tomography. Ann Nucl Med 2016; 30:534-43. [PMID: 27329083 DOI: 10.1007/s12149-016-1094-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/30/2016] [Indexed: 01/17/2023]
Abstract
OBJECTIVE We performed preclinical and first-in-man clinical positron emission tomography (PET) studies in human brain using N,N-di-n-propyl-2-[2-(4-[(11)C]methoxyphenyl)-6,8-dichloroimidazol[1,2-a]pyridine-3-yl]acetamide ([(11)C]CB184) to image the 18-kDa translocator protein (TSPO), which is overexpressed in activated microglia in neuroinflammatory conditions. METHODS In vitro selectivity of CB184 was characterized. The radiation absorbed dose by [(11)C]CB184 in humans was calculated from murine distribution data. Acute toxicity of CB184 hydrochloride in rats at a dose of 5.81 mg/kg body weight, which is >10,000-fold higher than the clinical equivalent dose of [(11)C]CB184, was evaluated. Acute toxicity of [(11)C]CB184 injection of a 400-fold dose to administer a postulated dose of 740 MBq [(11)C]CB184 was also evaluated after the decay-out of (11)C. The mutagenicity of CB184 was studied with a reverse mutation test (Ames test). The pharmacological effect of CB184 injection in mice was studied with an open field test. The first PET imaging of TSPO with [(11)C]CB184 in a normal human volunteer was performed. RESULTS A suitable preparation method for [(11)C]CB184 injection was established. CB184 showed low activity in a 28-standard receptor binding profile. The radiation absorbed dose by [(11)C]CB184 in humans was sufficiently low for clinical use, and no acute toxicity of CB184 or [(11)C]CB184 injection was found. No mutagenicity or apparent effect on locomotor activity or anxiety status was observed for CB184. We safely performed brain imaging with PET following administration of [(11)C]CB184 in a normal human volunteer. A 90-min dynamic scan showed rapid initial uptake of radioactivity in the brain followed by prompt clearance. [(11)C]CB184 was homogeneously distributed in the gray matter. The total distribution volume of [(11)C]CB184 was highest in the thalamus followed by the cerebellar cortex and elsewhere. Although regional differences were small, the observed [(11)C]CB184 binding pattern was consistent with the TSPO distribution in normal human brain. Peripherally, [(11)C]CB184 was metabolized in humans: 30 % of the radioactivity in plasma was detected as the unchanged form after 60 min. CONCLUSIONS [(11)C]CB184 is suitable for imaging TSPO in human brain and provides an acceptable radiation dose. Pharmacological safety was noted at the dose required for PET imaging.
Collapse
Affiliation(s)
- Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.
| | - Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kentaro Hatano
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Shuichi Yanai
- Research Team for Aging Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Shogo Endo
- Research Team for Aging Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Kenji Ishibashi
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kei Wagatsuma
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kenji Ishii
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kiichi Ishiwata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.,Institute of Cyclotron and Drug Discovery Research, Southern Tohoku Research Institute for Neuroscience, Koriyama, Japan.,Department of Biofunctional Imaging, Fukushima Medical University, Fukushima, Japan
| |
Collapse
|
15
|
Dumas N, Moulin-Sallanon M, Fender P, Tournier BB, Ginovart N, Charnay Y, Millet P. In Vivo Quantification of 5-HT2A Brain Receptors in Mdr1a KO Rats with 123I-R91150 Single-Photon Emission Computed Tomography. Mol Imaging 2016; 14. [PMID: 26105563 DOI: 10.2310/7290.2015.00006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Our goal was to identify suitable image quantification methods to image 5-hydroxytryptamine2A (5-HT2A) receptors in vivo in Mdr1a knockout (KO) rats (i.e., P-glycoprotein KO) using 123I-R91150 single-photon emission computed tomography (SPECT). The 123I-R91150 binding parameters estimated with different reference tissue models (simplified reference tissue model [SRTM], Logan reference tissue model, and tissue ratio [TR] method) were compared to the estimates obtained with a comprehensive three-tissue/seven-parameter (3T/7k)-based model. The SRTM and Logan reference tissue model estimates of 5-HT2A receptor (5-HT2AR) nondisplaceable binding potential (BPND) correlated well with the absolute receptor density measured with the 3T/7k gold standard (r > .89). Quantification of 5-HT2AR using the Logan reference tissue model required at least 90 minutes of scanning, whereas the SRTM required at least 110 minutes. The TR method estimates were also highly correlated to the 5-HT2AR density (r > .91) and only required a single 20-minute scan between 100 and 120 minutes postinjection. However, a systematic overestimation of the BPND values was observed. The Logan reference tissue method is more convenient than the SRTM for the quantification of 5-HT2AR in Mdr1a KO rats using 123I-R91150 SPECT. The TR method is an interesting and simple alternative, despite its bias, as it still provides a valid index of 5-HT2AR density.
Collapse
|
16
|
Tonietto M, Rizzo G, Veronese M, Fujita M, Zoghbi SS, Zanotti-Fregonara P, Bertoldo A. Plasma radiometabolite correction in dynamic PET studies: Insights on the available modeling approaches. J Cereb Blood Flow Metab 2016; 36:326-39. [PMID: 26661202 PMCID: PMC4759680 DOI: 10.1177/0271678x15610585] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 07/09/2015] [Indexed: 11/17/2022]
Abstract
Full kinetic modeling of dynamic PET images requires the measurement of radioligand concentrations in the arterial plasma. The unchanged parent radioligand must, however, be separated from its radiometabolites by chromatographic methods. Thus, only few samples can usually be analyzed and the resulting measurements are often noisy. Therefore, the measurements must be fitted with a mathematical model. This work presents a comprehensive analysis of the different models proposed in the literature to describe the plasma parent fraction (PPf) and of the alternative approaches for radiometabolite correction. Finally, we used a dataset of [(11)C]PBR28 brain PET data as a case study to guide the reader through the PPf model selection process.
Collapse
Affiliation(s)
- Matteo Tonietto
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Gaia Rizzo
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Mattia Veronese
- Department of Neuroimaging, IoPPN, King's College London, London, UK
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA INCIA UMR-CNRS 5287, Université de Bordeaux, Bordeaux, France
| | | |
Collapse
|
17
|
Shidahara M, Watabe H, Tashiro M, Okamura N, Furumoto S, Watanuki S, Furukawa K, Arakawa Y, Funaki Y, Iwata R, Gonda K, Kudo Y, Arai H, Ishiwata K, Yanai K. Quantitative kinetic analysis of PET amyloid imaging agents [11C]BF227 and [18F]FACT in human brain. Nucl Med Biol 2015; 42:734-44. [DOI: 10.1016/j.nucmedbio.2015.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/07/2015] [Accepted: 05/01/2015] [Indexed: 11/30/2022]
|
18
|
Improved models for plasma radiometabolite correction and their impact on kinetic quantification in PET studies. J Cereb Blood Flow Metab 2015; 35:1462-9. [PMID: 25873424 PMCID: PMC4640335 DOI: 10.1038/jcbfm.2015.61] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 11/08/2022]
Abstract
The quantification of dynamic positron emission tomography studies performed with arterial sampling usually requires correcting the input function for the presence of radiometabolites by using a model of the plasma parent fraction (PPf). Here, we show how to include the duration of radioligand injection in the PPf model formulations to achieve a more physiologic description of the plasma measurements. This formulation (here called convoluted model) was tested on simulated data and on three datasets with different parent kinetics: [(11)C]NOP-1A, [(11)C]MePPEP, and [(11)C](R)-rolipram. Results showed that convoluted PPf models better described the fraction of unchanged parent in the plasma compared with standard models for all three datasets (weighted residuals sum of squares up to 25% lower). When considering the effect on tissue quantification, the overall impact on the total volume of distribution (VT) was low. However, the impact was significant and radioligand-dependent on the binding potential (BP) and the microparameters (K1, k2, k3, and k4). Simulated data confirmed that quantification is sensitive to different degrees to PPf model misspecification. Including the injection duration allows obtaining a more accurate correction of the input function for the presence of radiometabolites and this yields a more reliable quantification of the tissue parameters.
Collapse
|
19
|
Lee DE, Reid WC, Ibrahim WG, Peterson KL, Lentz MR, Maric D, Choyke PL, Jagoda EM, Hammoud DA. Imaging dopaminergic dysfunction as a surrogate marker of neuropathology in a small-animal model of HIV. Mol Imaging 2015; 13. [PMID: 25248756 DOI: 10.2310/7290.2014.00031] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dopaminergic system is especially vulnerable to the effects of human immunodeficiency virus (HIV) infection, rendering dopaminergic deficits early surrogate markers of HIV-associated neuropathology. We quantified dopamine D2/3 receptors in young HIV-1 transgenic (Tg) (n = 6) and age-matched control rats (n = 7) and adult Tg (n = 5) and age-matched control rats (n = 5) using [18F]fallypride positron emission tomography (PET). Regional uptake was quantified as binding potential (BPND) using the two-tissue reference model with the cerebellum as the reference. Time-activity curves were generated for the ventral striatum, dorsal striatum, thalamus, and cerebellum. Whereas BPND values were significantly lower in the ventral striatum (p < .001) and dorsal striatum (p = .001) in the adult Tg rats compared to controls rats, they were significantly lower only in the dorsal striatum (p < .05) in the young rats. Tg rats had smaller striatal volumes on magnetic resonance imaging. We also found lower expression levels of tyrosine hydroxylase on immunohistochemistry in the Tg animals. Our findings suggest that progressive striatal D2/3 receptor deficits occur in Tg rats as they age and can be detected using small-animal PET imaging. The effectiveness of various approaches in preventing or halting this dopaminergic loss in the Tg rat can thus be measured preclinically using [18F]fallypride PET as a molecular imaging biomarker of HIV-associated neuropathology.
Collapse
|
20
|
Verwer EE, Oprea-Lager DE, van den Eertwegh AJM, van Moorselaar RJA, Windhorst AD, Schwarte LA, Hendrikse NH, Schuit RC, Hoekstra OS, Lammertsma AA, Boellaard R. Quantification of 18F-fluorocholine kinetics in patients with prostate cancer. J Nucl Med 2015; 56:365-71. [PMID: 25678491 DOI: 10.2967/jnumed.114.148007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
UNLABELLED Choline kinase is upregulated in prostate cancer, resulting in increased (18)F-fluoromethylcholine uptake. This study used pharmacokinetic modeling to validate the use of simplified methods for quantification of (18)F-fluoromethylcholine uptake in a routine clinical setting. METHODS Forty-minute dynamic PET/CT scans were acquired after injection of 204 ± 9 MBq of (18)F-fluoromethylcholine, from 8 patients with histologically proven metastasized prostate cancer. Plasma input functions were obtained using continuous arterial blood-sampling as well as using image-derived methods. Manual arterial blood samples were used for calibration and correction for plasma-to-blood ratio and metabolites. Time-activity curves were derived from volumes of interest in all visually detectable lymph node metastases. (18)F-fluoromethylcholine kinetics were studied by nonlinear regression fitting of several single- and 2-tissue plasma input models to the time-activity curves. Model selection was based on the Akaike information criterion and measures of robustness. In addition, the performance of several simplified methods, such as standardized uptake value (SUV), was assessed. RESULTS Best fits were obtained using an irreversible compartment model with blood volume parameter. Parent fractions were 0.12 ± 0.4 after 20 min, necessitating individual metabolite corrections. Correspondence between venous and arterial parent fractions was low as determined by the intraclass correlation coefficient (0.61). Results for image-derived input functions that were obtained from volumes of interest in blood-pool structures distant from tissues of high (18)F-fluoromethylcholine uptake yielded good correlation to those for the blood-sampling input functions (R(2) = 0.83). SUV showed poor correlation to parameters derived from full quantitative kinetic analysis (R(2) < 0.34). In contrast, lesion activity concentration normalized to the integral of the blood activity concentration over time (SUVAUC) showed good correlation (R(2) = 0.92 for metabolite-corrected plasma; 0.65 for whole-blood activity concentrations). CONCLUSION SUV cannot be used to quantify (18)F-fluoromethylcholine uptake. A clinical compromise could be SUVAUC derived from 2 consecutive static PET scans, one centered on a large blood-pool structure during 0-30 min after injection to obtain the blood activity concentrations and the other a whole-body scan at 30 min after injection to obtain lymph node activity concentrations.
Collapse
Affiliation(s)
- Eline E Verwer
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Daniela E Oprea-Lager
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | | | | | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Lothar A Schwarte
- Department of Anesthesiology, VU University Medical Center, Amsterdam, The Netherlands
| | - N Harry Hendrikse
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Robert C Schuit
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Otto S Hoekstra
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
21
|
Development of novel chiral capillary electrophoresis methods for the serotonin receptor (5-HT2A) antagonist MDL 100,907 (volinanserin) and for its key intermediate compound. J Pharm Biomed Anal 2013; 88:579-83. [PMID: 24216279 DOI: 10.1016/j.jpba.2013.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/01/2013] [Accepted: 10/06/2013] [Indexed: 11/21/2022]
Abstract
Enantioselective capillary electrophoretic methods were elaborated for the determination of the enantiomeric purity of (R)-MDL 100,907 and its preparatively resolved key intermediate compound during the synthesis route. The pKa values of the intermediate compound and the end product determined by CE were 10.5±0.1 and 9.0±0.1, respectively. The enantiopurity of the intermediate compound can be monitored in fully protonated state by applying 15mM sulfobutylether-β-cyclodextrin at pH 5 when the peak belonging to the impurity migrates before the main component. The fact that the consecutive steps of the synthesis do not affect the enantiomeric purity was verified by the other, newly developed CE method. The enantiomers of rac-MDL 100,907 were resolved by 15mM carboxymethyl-γ-cyclodextrin at pH 3. The applicability (selectivity, LOD, LOQ, repeatability, precision and accuracy) of the methods was studied as well.
Collapse
|
22
|
Analysis of 5-HT2A Receptor Binding with [11C]MDL 100907 in Rats: Optimization of Kinetic Modeling. Mol Imaging Biol 2013; 15:730-8. [DOI: 10.1007/s11307-013-0633-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
23
|
Hansen HD, Ettrup A, Herth MM, Dyssegaard A, Ratner C, Gillings N, Knudsen GM. Direct comparison of [(18) F]MH.MZ and [(18) F] altanserin for 5-HT2A receptor imaging with PET. Synapse 2013; 67:328-37. [PMID: 23390031 DOI: 10.1002/syn.21643] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 01/29/2013] [Indexed: 11/08/2022]
Abstract
Imaging the cerebral serotonin 2A (5-HT2A ) receptors with positron emission tomography (PET) has been carried out in humans with [(11) C]MDL 100907 and [(18) F]altanserin. Recently, the MDL 100907 analogue [(18) F]MH.MZ was developed combining the selectivity profile of MDL 100907 and the favourable radiophysical properties of fluorine-18. Here, we present a direct comparison of [(18) F]altanserin and [(18) F]MH.MZ. 5-HT2A receptor binding in pig cortex and cerebellum was investigated by autoradiography with [(3) H]MDL 100907, [(18) F]MH.MZ, and [(18) F]altanserin. [(18) F]MH.MZ and [(18) F]altanserin were investigated in Danish Landrace pigs by brain PET scanning at baseline and after i.v. administration of blocking doses of ketanserin. Full arterial input function and high performance liquid chromatography (HPLC) analysis allowed for tissue-compartment kinetic modeling of PET data. In vitro autoradiography showed high binding in cortical regions with both [(18) F]MH.MZ and [(18) F]altanserin. Significant 5-HT2A receptor binding was also found in the pig cerebellum, thus making this region unsuitable as a reference region for in vivo data analysis in this species. The cortical binding of [(18) F]MH.MZ and [(18) F]altanserin was blocked by ketanserin supporting that both radioligands bind to 5-HT2A receptors in the pig brain. In the HPLC analysis of pig plasma, [(18) F]MH.MZ displayed a fast and reproducible metabolism resulting in hydrophilic radiometabolites only whereas the metabolic profile of [(18) F]altanserin as expected showed lipophilic radiometabolites. Due to the slow kinetics of [(18) F]MH.MZ in high-binding regions in vivo, we suggest that [(18) F]MH.MZ will be an appropriate tracer for low binding regions where kinetics will be faster, whereas [(18) F]altanserin is a suitable tracer for high-binding regions.
Collapse
Affiliation(s)
- Hanne D Hansen
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, Copenhagen DK-2100, Denmark
| | | | | | | | | | | | | |
Collapse
|
24
|
Veronese M, Gunn RN, Zamuner S, Bertoldo A. A non-linear mixed effect modelling approach for metabolite correction of the arterial input function in PET studies. Neuroimage 2012; 66:611-22. [PMID: 23108277 DOI: 10.1016/j.neuroimage.2012.10.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/02/2012] [Accepted: 10/05/2012] [Indexed: 10/27/2022] Open
Abstract
Quantitative PET studies with arterial blood sampling usually require the correction of the measured total plasma activity for the presence of metabolites. In particular, if labelled metabolites are found in the plasma in significant amounts their presence has to be accounted for, because it is the concentration of the parent tracer which is required for data quantification. This is achieved by fitting a Parent Plasma fraction (PPf) model to discrete metabolite measurements. The commonly used method is based on an individual approach, i.e. for each subject the PPf model parameters are estimated from its own metabolite samples, which are, in general, sparse and noisy. This fact can compromise the quality of the reconstructed arterial input functions, and, consequently, affect the quantification of tissue kinetic parameters. In this study, we proposed a Non-Linear Mixed Effect Modelling (NLMEM) approach to describe metabolite kinetics. Since NLMEM has been developed to provide robust parameter estimates in the case of sparse and/or noisy data, it has the potential to be a reliable method for plasma metabolite correction. Three different PET datasets were considered: [11C]-(+)-PHNO (54 scans), [11C]-PIB (22 scans) and [11C]-DASB (30 scans). For each tracer both simulated and measured data were considered and NLMEM performance was compared with that provided by individual analysis. Results showed that NLMEM provided improved estimates of the plasma parent input function over the individual approach when the metabolite data were sparse or contained outliers.
Collapse
Affiliation(s)
- Mattia Veronese
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Roger N Gunn
- Imanova Limited, London, UK; Department of Medicine, Imperial College London, London, UK; Department of Engineering Science, University of Oxford, Oxford, UK
| | - Stefano Zamuner
- Clinical Pharmacology, Modelling and Simulation, GlaxoSmithKline, Stockley Park, UK
| | | |
Collapse
|
25
|
Direct radiofluorination of [18F]MH.MZ for 5-HT2A receptor molecular imaging with PET. J Labelled Comp Radiopharm 2012. [DOI: 10.1002/jlcr.2947] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
26
|
Abstracts of the Ninth International Symposium on Functional Neuroreceptor Mapping of the Living Brain. August 9-11, 2012. J Cereb Blood Flow Metab 2012; 32 Suppl 1:S13-196. [PMID: 22872875 PMCID: PMC3421080 DOI: 10.1038/jcbfm.2012.77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
27
|
Talbot PS, Slifstein M, Hwang DR, Huang Y, Scher E, Abi-Dargham A, Laruelle M. Extended characterisation of the serotonin 2A (5-HT2A) receptor-selective PET radiotracer 11C-MDL100907 in humans: quantitative analysis, test-retest reproducibility, and vulnerability to endogenous 5-HT tone. Neuroimage 2011; 59:271-85. [PMID: 21782029 DOI: 10.1016/j.neuroimage.2011.07.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/29/2011] [Accepted: 07/01/2011] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Scanning properties and analytic methodology of the 5-HT2A receptor-selective positron emission tomography (PET) tracer 11C-MDL100907 have been partially characterised in previous reports. We present an extended characterisation in healthy human subjects. METHODS 64 11C-MDL100907 PET scans with metabolite-corrected arterial input function were performed in 39 healthy adults (18-55 years). 12 subjects were scanned twice (duration 150 min) to provide data on plasma analysis, model order estimation, and stability and test-retest characteristics of outcome measures. All other scans were 90 min duration. 3 subjects completed scanning at baseline and following 5-HT2A receptor antagonist medication (risperidone or ciproheptadine) to provide definitive data on the suitability of the cerebellum as reference region. 10 subjects were scanned under reduced 5-HT and control conditions using rapid tryptophan depletion to investigate vulnerability to competition with endogenous 5-HT. 13 subjects were scanned as controls in clinical protocols. Pooled data were used to analyse the relationship between tracer injected mass and receptor occupancy, and age-related decline in 5-HT2A receptors. RESULTS Optimum analytic method was a 2-tissue compartment model with arterial input function. However, basis function implementation of SRTM may be suitable for measuring between-group differences non-invasively and warrants further investigation. Scan duration of 90 min achieved stable outcome measures in all cortical regions except orbitofrontal which required 120 min. Binding potential (BPP and BPND) test-retest variability was very good (7-11%) in neocortical regions other than orbitofrontal, and moderately good (14-20%) in orbitofrontal cortex and medial temporal lobe. Saturation occupancy of 5-HT2A receptors by risperidone validates the use of the cerebellum as a region devoid of specific binding for the purposes of PET. We advocate a mass limit of 4.6 μg to remain below 5% receptor occupancy. 11C-MDL100907 specific binding is not vulnerable to competition with endogenous 5-HT in humans. Paradoxical decreases in BPND were found in right prefrontal cortex following reduced 5-HT, possibly representing receptor internalisation. Mean age-related decline in brain 5-HT2A receptors was 14.0±5.0% per decade, and higher in prefrontal regions. CONCLUSIONS Our data confirm and extend support for 11C-MDL100907 as a PET tracer with very favourable properties for quantifying 5-HT2A receptors in the human brain.
Collapse
Affiliation(s)
- Peter S Talbot
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY 10032, USA.
| | | | | | | | | | | | | |
Collapse
|
28
|
Paterson LM, Kornum BR, Nutt DJ, Pike VW, Knudsen GM. 5-HT radioligands for human brain imaging with PET and SPECT. Med Res Rev 2011; 33:54-111. [PMID: 21674551 DOI: 10.1002/med.20245] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT(1A), 5-HT(1B), 5-HT(2A), and 5-HT(4) receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging.
Collapse
Affiliation(s)
- Louise M Paterson
- Neuropsychopharmacology Unit, Division of Experimental Medicine, Imperial College London, Burlington Danes Building, Du Cane Road, London, United Kingdom
| | | | | | | | | |
Collapse
|
29
|
Synthesis, radiofluorination and first evaluation of [18F]fluorophenylsulfonyl- and [18F]fluorophenylsulfinyl-piperidines as serotonin 5-HT2A receptor antagonists for PET. Nucl Med Biol 2010; 37:605-14. [PMID: 20610165 DOI: 10.1016/j.nucmedbio.2010.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 02/04/2010] [Accepted: 03/08/2010] [Indexed: 11/23/2022]
Abstract
In psychiatric disorders, 5-HT(2A) receptors play an important role. In order to study these receptors in vivo by positron emission tomography (PET), there is an increasing interest for subtype selective and high affinity radioligands. Up to now, no optimal radiotracer is available. Thus, 1-(2,4-difluorophenethyl)-4-(4-fluorophenylsulfonyl)piperidine (9), possessing high affinity and sufficient subtype selectivity for 5-HT(2A) receptors, and 1-(2,4-difluorophenethyl)-4-(4-fluorophenylsulfinyl)piperidine (15) have been (18)F-labelled by a nucleophilic one-step reaction. Both radiotracers could be prepared and isolated within 45 min, [(18)F]9 in a radiochemical yield (RCY) of 34.5+/-8% and [(18)F]15 of 9.5+/-2.5%. The K(i) values of 9 and 15 at 5-HT(2A) receptors towards [(3)H]ketanserin were determined to be 1.9+/-0.6 and 198+/-8 nM, respectively. Autoradiography with [(18)F]9 and [(18)F]15 on rat brain sections showed a very high nonspecific binding of >80% for [(18)F]9 and 30% to 40% nonspecific binding for [(18)F]15; however, it is still too high in order to compensate for its lower affinity. Even though the affinity of 9 is more promising compared with 15, the high nonspecific binding of both radiofluorinated tracers in rat brain does not recommend those as an in vivo PET imaging agent for serotonin 5-HT(2A) receptors in humans.
Collapse
|
30
|
Debus F, Herth MM, Piel M, Buchholz HG, Bausbacher N, Kramer V, Lüddens H, Rösch F. 18F-Labeling and evaluation of novel MDL 100907 derivatives as potential 5-HT2A antagonists for molecular imaging. Nucl Med Biol 2010; 37:487-95. [DOI: 10.1016/j.nucmedbio.2010.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 02/03/2010] [Accepted: 02/06/2010] [Indexed: 10/19/2022]
|
31
|
Simplified quantification of 5-HT2A receptors in the human brain with [11C]MDL 100,907 PET and non-invasive kinetic analyses. Neuroimage 2010; 50:984-93. [DOI: 10.1016/j.neuroimage.2010.01.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 01/08/2010] [Accepted: 01/09/2010] [Indexed: 11/24/2022] Open
|
32
|
Abstract
[(11)C]P943 is a new radioligand recently developed to image and quantify serotonin 5-Hydroxytryptamine (5-HT(1B)) receptors with positron emission tomography (PET). The purpose of this study was to evaluate [(11)C]P943 for this application in humans, and to determine the most suitable quantification method. Positron emission tomography data and arterial input function measurements were acquired in a cohort of 32 human subjects. Using arterial input functions, compartmental modeling, the Logan graphical analysis, and the multilinear method MA1 were tested. Both the two tissue-compartment model and MA1 provided good fits of the PET data and reliable distribution volume estimates. Using the cerebellum as a reference region, BP(ND) binding potential estimates were computed. [(11)C]P943 BP(ND) estimates were significantly correlated with in vitro measurements of the density of 5-HT(1B) receptors, with highest values in the occipital cortex and pallidum. To evaluate noninvasive methods, two- and three-parameter graphical analyses, Simplified Reference Tissue Models (SRTM and SRTM2), and Multilinear Reference Tissue Models (MRTM and MRTM2) were tested. The MRTM2 model provided the best correlation with MA1 binding-potential estimates. Parametric images of the volume of distribution or binding potential of [(11)C]P943 could be computed using both MA1 and MRTM2. The results show that [(11)C]P943 provides quantitative measurements of 5-HT(1B) binding potential.
Collapse
|
33
|
Multi-graphical analysis of dynamic PET. Neuroimage 2009; 49:2947-57. [PMID: 19931403 DOI: 10.1016/j.neuroimage.2009.11.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/01/2009] [Accepted: 11/11/2009] [Indexed: 11/22/2022] Open
Abstract
In quantitative dynamic PET studies, graphical analysis methods including the Gjedde-Patlak plot, the Logan plot, and the relative equilibrium-based graphical plot (RE plot) (Zhou Y., Ye W., Brasić J.R., Crabb A.H., Hilton J., Wong D.F. 2009b. A consistent and efficient graphical analysis method to improve the quantification of reversible tracer binding in radioligand receptor dynamic PET studies. Neuroimage 44(3):661-670) are based on the theory of a compartmental model with assumptions on tissue tracer kinetics. If those assumptions are violated, then the resulting estimates may be biased. In this study, a multi-graphical analysis method was developed to characterize the non-relative equilibrium effects on the estimates of total distribution volume (DV(T)) from the RE plot. A novel bi-graphical analysis method using the RE plot with the Gjedde-Patlak plot (RE-GP plots) was proposed to estimate DV(T) for the quantification of reversible tracer kinetics that may not be at relative equilibrium states during PET study period. The RE-GP plots and the Logan plot were evaluated by 19 [(11)C]WIN35,428 and 10 [(11)C]MDL100,907 normal human dynamic PET studies with brain tissue tracer kinetics measured at both region of interest (ROI) and pixel levels. A 2-tissue compartment model (2TCM) was used to fit ROI time activity curves (TACs). By applying multi-graphical plots to the 2TCM fitted ROI TACs which were considered as the noise-free tracer kinetics, the estimates of DV(T) from the RE-GP plots, the Logan plot, and the 2TCM fitting were equal to each other. For the measured ROI TACs, there was no significant difference between the estimates of the DV(T) from the RE-GP plots and those from 2TCM fitting (p=0.77), but the estimates of the DV(T) from the Logan plot were significantly (p<0.001) lower, 2.3% on average, than those from 2TCM fitting. There was a highly linear correlation between the ROI DV(T) from the parametric images (Y) and those from the ROI kinetics (X) by using the RE-GP plots (Y=1.01X+0.23, R(2)=0.99). For the Logan plot, the ROI estimates from the parametric images were 13% to 83% lower than those from ROI kinetics. The computational time for generating parametric images was reduced by 69% on average by the RE-GP plots in contrast to the Logan plot. In conclusion, the bi-graphical analysis method using the RE-GP plots was a reliable, robust and computationally efficient kinetic modeling approach to improve the quantification of dynamic PET.
Collapse
|
34
|
Herth MM, Piel M, Debus F, Schmitt U, Lüddens H, Rösch F. Preliminary in vivo and ex vivo evaluation of the 5-HT2A imaging probe [(18)F]MH.MZ. Nucl Med Biol 2009; 36:447-54. [PMID: 19423013 DOI: 10.1016/j.nucmedbio.2009.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 01/16/2009] [Accepted: 01/25/2009] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The 5-HT(2A) receptor is one of the most interesting targets within the serotonergic system because it is involved in a number of important physiological processes and diseases. METHODS [(18)F]MH.MZ, a 5-HT(2A) antagonistic receptor ligand, is labeled by (18)F-fluoroalkylation of the corresponding desmethyl analogue MDL 105725 with 2-[(18)F]fluoroethyltosylate ([(18)F]FETos). In vitro binding experiments were performed to test selectivity toward a broad spectrum of neuroreceptors by radioligand binding assays. Moreover, first micro-positron emission tomography (microPET) experiments, ex vivo organ biodistribution, blood cell and protein binding and brain metabolism studies of [(18)F]MH.MZ were carried out in rats. RESULTS [(18)F]MH.MZ showed a K(i) of 3 nM toward the 5-HT(2A) receptor and no appreciable affinity for a variety of receptors and transporters. Ex vivo biodistribution as well as microPET showed highest brain uptake at approximately 5 min p.i. and steady state after approximately 30 min p.i. While [(18)F]MH.MZ undergoes extensive first-pass metabolism which significantly reduces its bioavailability, it is insignificantly metabolized within the brain. The binding potential in the rat frontal cortex is 1.45, whereas the cortex to cerebellum ratio was determined to be 2.7 after approximately 30 min. CONCLUSION Results from microPET measurements of [(18)F]MH.MZ are in no way inferior to data known for [(11)C]MDL 100907 at least in rats. [(18)F]MH.MZ appears to be a highly potent and selective serotonergic PET ligand in small animals.
Collapse
Affiliation(s)
- Matthias M Herth
- Institute of Nuclear Chemistry, Johannes Gutenberg-University Mainz, D-55128 Mainz, Germany.
| | | | | | | | | | | |
Collapse
|
35
|
Hiraoka K, Okamura N, Funaki Y, Watanuki S, Tashiro M, Kato M, Hayashi A, Hosokai Y, Yamasaki H, Fujii T, Mori E, Yanai K, Watabe H. Quantitative analysis of donepezil binding to acetylcholinesterase using positron emission tomography and [5-(11)C-methoxy]donepezil. Neuroimage 2009; 46:616-23. [PMID: 19286462 DOI: 10.1016/j.neuroimage.2009.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 02/24/2009] [Accepted: 03/04/2009] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to establish kinetic analysis of [5-(11)C-methoxy]donepezil ([(11)C]donepezil), which was developed for the in-vivo visualization of donepezil binding to acetylcholinesterase (AChE) using positron emission tomography (PET). Donepezil is an AChE inhibitor that is widely prescribed to ameliorate the cognitive impairment of patients with dementia. Six healthy subjects took part in a dynamic study involving a 60-min PET scan after intravenous injection of [(11)C]donepezil. The total distribution volume (tDV) of [(11)C]donepezil was quantified by compartmental kinetic analysis and Logan graphical analysis. A one-tissue compartment model (1TCM) and a two-tissue compartment model (2TCM) were applied in the kinetic analysis. Goodness of fit was assessed with chi(2) criterion and Akaike's Information Criterion (AIC). Compared with a 1TCM, goodness of fit was significantly improved by a 2TCM. The tDVs provided by Logan graphical analysis were slightly lower than those provided by a 2TCM. The rank order of the mean tDVs in 10 regions was in line with the AChE activity reported in a previous post-mortem study. Logan graphical analysis generated voxel-wise images of tDV, revealing the overall distribution pattern of AChE in individual brains. Significant correlation was observed between tDVs calculated with and without metabolite correction for plasma time-activity curves, indicating that metabolite correction could be omitted. In conclusion, this method enables quantitative analysis of AChE and direct investigation of the pharmacokinetics of donepezil in the human brain.
Collapse
Affiliation(s)
- Kotaro Hiraoka
- Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Elfving B, Madsen J, Knudsen GM. Neuroimaging of the serotonin reuptake site requires high-affinity ligands. Synapse 2007; 61:882-8. [PMID: 17657807 DOI: 10.1002/syn.20443] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Numerous attempts have been made to develop suitable radiolabeled tracers for positron emission tomography or single photon emission computed tomography imaging of the serotonin transporter (SERT), but most often, negative outcomes are reported. The aim of this study is to define characteristics of a good SERT radioligand and to investigate species differences. We examined seven different selective serotonin reuptake inhibitors (SSRIs) and that except for one all have been previously tested as emission tomography ligands. The outcome of the ligands as emission tomography tracers was compared in relation with receptor density (Bmax) and/or ligand affinity (Kd) in rat and monkey cerebrum and cerebellum (reference region) membranes. [3H]-(S)-Citalopram and [3H]-(+)-McN5652 display statistically significantly lower affinity, whereas [3H]paroxetine displays statistically significantly higher affinity for SERT in monkey cortex when compared with the rat cerebrum. The affinity of [3H]MADAM, [123I]ADAM, and [11C]DASB for SERT obtained with rat cerebrum and monkey cortex are similar. In monkey cortex, Kd and Bmax could not be determined with [3H]fluoxetine. Of the seven SSRIs, [3H]-(S)-citalopram, [3H]MADAM, and [11C]DASB displayed significant specific binding to SERT in monkey cerebellum, with Bmax cortex:cerebellum ratios being 17, 3, and 4, respectively. In rat brain tissue the ratios were 12, 6, and 3, respectively. In conclusion, it can be estimated that imaging of the human SERT in a high-density region requires radioligands with Kd values between 0.03 and a maximum of 0.3 nM (at 37 degrees C). The differential specific cerebellar binding raises the question of the suitability of cerebellum as a reference region for nonspecific binding.
Collapse
Affiliation(s)
- Betina Elfving
- Neurobiology Research Unit N9201, Rigshospitalet, University Hospital Copenhagen, DK-2100 Copenhagen, Denmark.
| | | | | |
Collapse
|
37
|
Bohnen NI, Frey KA. Imaging of cholinergic and monoaminergic neurochemical changes in neurodegenerative disorders. Mol Imaging Biol 2007; 9:243-57. [PMID: 17318670 DOI: 10.1007/s11307-007-0083-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Positron emission tomography (PET) or single photon emission computer tomography (SPECT) imaging provides the means to study neurochemical processes in vivo. These methods have been applied to examine monoaminergic and cholinergic changes in neurodegenerative disorders. These investigations have provided important insights into disorders, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The most intensely studied monoaminergic transmitter is dopamine. The extent of presynaptic nigrostriatal dopaminergic denervation can be quantified in PD and may serve as a diagnostic biomarker. Dopaminergic receptor imaging may help to distinguish idiopathic PD from atypical parkinsonian disorders. Cholinergic denervation has been identified not only in AD but also in PD and more severely in parkinsonian dementia. PET or SPECT can also provide biomarkers to follow progression of disease or evaluate the effects of therapeutic interventions. Cholinergic receptor imaging is expected to play a major role in new drug development for dementing disorders.
Collapse
Affiliation(s)
- Nicolaas I Bohnen
- Departments of Radiology & Neurology, The University of Michigan Medical School, Ann Arbor, MI, USA
| | | |
Collapse
|
38
|
Ekelund J, Slifstein M, Narendran R, Guillin O, Belani H, Guo NN, Hwang Y, Hwang DR, Abi-Dargham A, Laruelle M. In vivo DA D(1) receptor selectivity of NNC 112 and SCH 23390. Mol Imaging Biol 2007; 9:117-25. [PMID: 17473957 DOI: 10.1007/s11307-007-0077-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE [(11)C]NNC 112 and [(11)C]SCH 23390 are selective positron emission tomography (PET) tracers for visualizing dopamine D(1) receptors. It is known that both have some affinity for serotonin 2A receptors, but previous studies have suggested this is negligible compared to D(1) affinity. We sought to verify this property in vivo. PROCEDURES Two baboons were scanned to measure the selectivity of both tracers with a displacement paradigm. Four baboons were scanned to directly assess [(11)C] NNC 112 affinity for both receptors. RESULTS In vivo, D(1) to 5-HT(2A) selectivity is six to fourteenfold, not 100-fold as previously reported by other investigators. CONCLUSION We conclude that about 1/4 of the cortical signal of both [(11)C]NNC 112 and [(11)C]SCH 23390 is due to binding to 5-HT(2A) receptors. If confirmed in humans, this suggests caution should be exercised when drawing conclusions from studies using either tracer. These results also indicate the need for more selective tracers for the D(1) receptor.
Collapse
Affiliation(s)
- Jesper Ekelund
- Department of Psychiatry, Columbia University, New York, NY, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Watabe H, Ikoma Y, Kimura Y, Naganawa M, Shidahara M. PET kinetic analysis--compartmental model. Ann Nucl Med 2007; 20:583-8. [PMID: 17294668 DOI: 10.1007/bf02984655] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PET enables not only visualization of the distribution of radiotracer, but also has ability to quantify several biomedical functions. Compartmental model is a basic idea to analyze dynamic PET data. This review describes the principle of the compartmental model and categorizes the techniques and approaches for the compartmental model according to various aspects: model design, experimental design, invasiveness, and mathematical solution. We also discussed advanced applications of the compartmental analysis with PET.
Collapse
Affiliation(s)
- Hiroshi Watabe
- Department of Investigative Radiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
| | | | | | | | | |
Collapse
|
40
|
Sakata M, Kimura Y, Naganawa M, Oda K, Ishii K, Chihara K, Ishiwata K. Mapping of human cerebral sigma1 receptors using positron emission tomography and [11C]SA4503. Neuroimage 2007; 35:1-8. [PMID: 17240168 DOI: 10.1016/j.neuroimage.2006.11.055] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 10/20/2006] [Accepted: 11/27/2006] [Indexed: 11/16/2022] Open
Abstract
The objective of this study was to establish the kinetic analysis for mapping sigma(1) receptors (sigma1Rs) in the human brain by positron emission tomography (PET) with [(11)C]SA4503. The sigma1Rs are considered to be involved in various neurological and psychiatric diseases. [(11)C]SA4503 is a recently developed radioligand with high and selective affinity for sigma1Rs, and we have first applied it to clinical studies. Nine healthy male subjects each underwent a dynamic 90-min PET scan after injection of [(11)C]SA4503. In addition to the baseline measurement, three of the nine subjects underwent a second [(11)C]SA4503-PET after partial blockade of sigma1Rs by oral administration of haloperidol, a sigma receptor antagonist. Full kinetic analysis using two times nonlinear estimations was applied for fitting a two-tissue three-compartment model to determine the binding potential (BP) and total distribution volume (tDV) of [(11)C]SA4503. Graphical analysis with a Logan plot was also applied for estimations of tDV. The regional distribution patterns of BP and tDV in 11 regions were compatible with those of previously reported sigma1Rs in vitro. The reduced binding sites of sigma1Rs by haloperidol were appropriately evaluated. The tDVs derived from the two methods matched each other well. The Logan plot offered images of the tDV, which reflected sigma1R densities, and the tDV in the images decreased after haloperidol loading. Moreover, comparison of BPs calculated with and without metabolite correction for plasma input function indicated that the metabolite correction could be omitted. We concluded that this method enables the quantitative analysis of sigma1Rs in the human brain.
Collapse
Affiliation(s)
- Muneyuki Sakata
- Graduate School of Information Science, Nara Institute of Science and Technology, Japan
| | | | | | | | | | | | | |
Collapse
|
41
|
Hinz R, Bhagwagar Z, Cowen PJ, Cunningham VJ, Grasby PM. Validation of a tracer kinetic model for the quantification of 5-HT(2A) receptors in human brain with [(11)C]MDL 100,907. J Cereb Blood Flow Metab 2007; 27:161-72. [PMID: 16685260 DOI: 10.1038/sj.jcbfm.9600323] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The positron emission tomography (PET) ligand [(11)C]MDL 100,907 has previously been introduced to image the serotonin 2A (5-HT(2A)) receptor in human brain. The aim of this work was to contribute to the verification of the tracer kinetic modelling in human studies. Five healthy volunteers were scanned twice after intravenous bolus injection of approximately 370 MBq [(11)C]MDL 100,907 using dynamic PET. One scan was performed under baseline condition, the other scan commenced 90 mins after a single oral dose of 30 mg of the antidepressant mirtazapine, which binds to the 5-HT(2A) receptor. There did not appear to be radiolabelled metabolites of [(11)C]MDL 100,907 in human plasma, which are likely to cross the blood-brain barrier. Total volumes of distribution VD in 11 different brain regions were estimated using a reversible, two tissue, four rate constants compartment model with a variable fractional blood volume term and the metabolite-corrected plasma input function. There were no significant changes of the VD in the cerebellum between the baseline and the blocked scans confirming the cerebellum as a region devoid of displaceable binding. Regional estimates of binding potential were then obtained indirectly using the cerebellar VD and occupancies calculated. The mean occupancy with this clinically effective dose of mirtazapine was 60% without significant regional differences. This study confirmed the use of an arterial input kinetic model for the quantification of 5-HT(2A) receptor binding with [(11)C]MDL 100,907 and the use of the cerebellum as a reference region for the free and nonspecific binding.
Collapse
MESH Headings
- Adult
- Antidepressive Agents/pharmacology
- Brain/diagnostic imaging
- Brain Chemistry/drug effects
- Carbon Radioisotopes
- Chromatography, High Pressure Liquid
- Data Interpretation, Statistical
- Female
- Fluorobenzenes
- Humans
- Image Processing, Computer-Assisted
- Kinetics
- Magnetic Resonance Imaging
- Male
- Mianserin/analogs & derivatives
- Mianserin/pharmacology
- Middle Aged
- Mirtazapine
- Models, Neurological
- Models, Statistical
- Piperidines
- Positron-Emission Tomography
- Radiopharmaceuticals
- Receptor, Serotonin, 5-HT2A/drug effects
- Receptor, Serotonin, 5-HT2A/metabolism
- Reproducibility of Results
- Serotonin Antagonists/pharmacology
- Spectrophotometry, Ultraviolet
Collapse
|
42
|
Blanckaert P, Burvenich I, Devos F, Slegers G. Synthesis andin vivo evaluation in mice of [123I]-(4-fluorophenyl)[1-(3-iodophenethyl)piperidin-4-yl]methanone as a potential SPECT-tracer for the serotonin 5-HT2A receptor. J Labelled Comp Radiopharm 2007. [DOI: 10.1002/jlcr.1251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
43
|
Naganawa M, Kimura Y, Mishina M, Manabe Y, Chihara K, Oda K, Ishii K, Ishiwata K. Quantification of adenosine A2A receptors in the human brain using [11C]TMSX and positron emission tomography. Eur J Nucl Med Mol Imaging 2006; 34:679-687. [PMID: 17171358 DOI: 10.1007/s00259-006-0294-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 09/20/2006] [Indexed: 11/27/2022]
Abstract
PURPOSE [7-methyl-(11)C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine ([(11)C]TMSX) is a positron-emitting adenosine A(2A) receptor (A2AR) antagonist for visualisation of A2AR distribution by positron emission tomography (PET). The aims of this paper were to use a kinetic model to analyse the behaviour of [(11)C]TMSX in the brain and to examine the applicability of the Logan plot. We also studied the applicability of a simplified Logan plot by omitting metabolite correction and arterial blood sampling. METHODS The centrum semiovale was used as a reference region on the basis of a post-mortem study showing that it has a negligibly low density of A2ARs. Compartmental analysis was performed in five normal subjects. Parametric images of A2AR binding potential (BP) were also generated using a Logan plot with or without metabolite correction and with or without arterial blood sampling. To omit arterial blood sampling, we applied a method to extract the plasma-related information using independent component analysis (EPICA). RESULTS The estimated K (1)/k (2) was confirmed to be common in the centrum semiovale and main cortices. The three-compartment model was well fitted to the other regions using the fixed value of K (1)/k (2) estimated from the centrum semiovale. The estimated BPs using the Logan plot matched those derived from compartment analysis. Without the metabolite correction, the estimate of BP underestimated the true value by 5%. The estimated BPs agreed regardless of arterial blood sampling. CONCLUSION A three-compartment model with a reference region, the centrum semiovale, describes the kinetic behaviour of [(11)C]TMSX PET images. A2ARs in the human brain can be visualised as a BP image using [(11)C]TMSX PET without arterial blood sampling.
Collapse
Affiliation(s)
- Mika Naganawa
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Yuichi Kimura
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022, Japan.
| | - Masahiro Mishina
- Neurological Institute, Nippon Medical School Chiba-Hokusoh Hospital, Chiba, Japan
| | - Yoshitsugu Manabe
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara, Japan
| | - Kunihiro Chihara
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara, Japan
| | - Keiichi Oda
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022, Japan
| | - Kenji Ishii
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022, Japan
| | - Kiichi Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022, Japan
| |
Collapse
|
44
|
Kumar JSD, Prabhakaran J, Erlandsson K, Majo VJ, Simpson NR, Pratap M, Van Heertum RL, Mann JJ, Parsey RV. Synthesis and in vivo evaluation of [O-methyl-11C](2R,4R)-4-hydroxy-2-[2-[2-[2-(3-methoxy)phenyl]ethyl]phenoxy]ethyl-1-methylpyrrolidine as a 5-HT2A receptor PET ligand. Nucl Med Biol 2006; 33:565-74. [PMID: 16720250 DOI: 10.1016/j.nucmedbio.2006.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 01/23/2006] [Accepted: 02/08/2006] [Indexed: 11/29/2022]
Abstract
The serotonin2A (5-HT2A) receptor is implicated in the pathophysiology of schizophrenia and mood disorders, and in vivo studies of this receptor would be of value in studying the pathophysiology of these disorders and in measuring the relationship of clinical response to receptor occupancy for 5-HT2A antagonists such as atypical antipsychotics. Therefore, (2R,4R)-4-hydroxy-2-[2-[2-[2-(3-methoxy)-phenyl]ethyl]phenoxy]ethyl-1-methylpyrrolidine (MPM) (13), a selective and high-affinity (K(i)=0.79 nM) 5HT2A antagonist, has been radiolabeled with carbon-11 by O-methylation of the corresponding desmethyl analogue (2R,4R)-4-hydroxy-2-[2-[2-[2-(3-hydroxy)phenyl]ethyl]phenoxy]ethyl-1-methylpyrrolidine (12) with [11C]methyltriflate in order to determine the suitability of [11C]MPM to quantify 5-HT2A in living brain using PET. Desmethyl-MPM 12 and standard MPM were prepared, starting from 3-hydroxymethylphenol (2), in excellent yield. The yield obtained for radiolabeling was 40+/-5% (EOB), and the total synthesis time was 30 min at EOS. PET studies with [11C]MPM in baboon showed a distribution in the brain consistent with the known distribution of 5-HT2A receptors. The time-activity curves for the high-binding regions peaked at approximately 45 min after injection. Blocking studies with M100907 demonstrated not only 38-57% blocking of tracer binding in brain regions known to have 5-HT2A receptors but also 38% blocking in cerebellum, which has a low 5-HT2A receptor concentration. Although [11C]MPM exhibits appropriate kinetics in baboon for imaging 5-HT2A receptors, its specific binding in cerebellum and higher proportion of nonspecific binding limit its usefulness for the in vivo quantification of 5-HT2A receptors with PET.
Collapse
Affiliation(s)
- J S Dileep Kumar
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Prabhakaran J, Parsey RV, Majo VJ, Van Heertum RL, John Mann J, Dileep Kumar JS. Synthesis andin vivo evaluation of [O-methyl-11C] 2-(4-methoxyphenyl)-N-(4-methylbenzyl)-N-(1-methyl- piperidin-4-yl)acetamide as an imaging probe for 5-HT2A receptors. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.1124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
46
|
Kimura Y, Ishii K, Fukumitsu N, Oda K, Sasaki T, Kawamura K, Ishiwata K. Quantitative analysis of adenosine A1 receptors in human brain using positron emission tomography and [1-methyl-11C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine. Nucl Med Biol 2005; 31:975-81. [PMID: 15607479 DOI: 10.1016/j.nucmedbio.2004.06.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 04/23/2004] [Accepted: 06/28/2004] [Indexed: 11/17/2022]
Abstract
Fully quantitative analysis of the adenosine A(1) receptor (A1R) in the brain with (11)C-MPDX and positron emission tomography is reported. The kinetics is described using a two-tissue three-compartment model, and estimated binding potentials correspond well with the estimates made by Logan plot. The image of the binding potential of the MPDX is physiologically reasonable. We conclude that MPDX is applicable to the visualization of the A1Rs in the brain with Logan plot.
Collapse
Affiliation(s)
- Yuichi Kimura
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo 173-0022, Japan.
| | | | | | | | | | | | | |
Collapse
|
47
|
Giovacchini G, Lang L, Ma Y, Herscovitch P, Eckelman WC, Carson RE. Differential effects of paroxetine on raphe and cortical 5-HT1A binding: a PET study in monkeys. Neuroimage 2005; 28:238-48. [PMID: 15993625 DOI: 10.1016/j.neuroimage.2005.05.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Revised: 05/03/2005] [Accepted: 05/19/2005] [Indexed: 10/25/2022] Open
Abstract
Positron emission tomography (PET) ligands that are sensitive to transient changes in serotonin (5-HT) concentration are desirable for studies of neuropsychiatric diseases. Few studies, however, have sought to demonstrate that variations in 5-HT concentration can be closely tracked with available serotonergic ligands. Microdialysis studies in rats have shown a maximal increase in 5-HT concentration in raphe nuclei after systemic infusion of selective serotonergic re-uptake inhibitors (SSRIs). We performed PET scans with [(18)F]FPWAY, an intermediate-affinity antagonist of 5-HT(1A) receptors, in 4 anesthetized rhesus monkeys in control studies and after systemic paroxetine administration (5 mg/kg, i.v.). In addition, a paired [(11)C]DASB study revealed that this paroxetine regimen produced an occupancy of 54-83% of the serotonin transporters. According to the conventional receptor competition model, increased 5-HT concentration produces decreased binding of the radioactive ligand. Over a 3-h period following paroxetine infusion, a progressively increasing reduction (ranging from 8 +/- 6% to 27 +/- 10%) of [(18)F]FPWAY-specific binding was found in the raphe nuclei. This result is interpreted as an SSRI-induced increase in 5-HT concentration, potentially combined with reduced binding to internalized 5-HT(1A) receptors. In addition, a transient (1 h) increase in cerebral cortical binding was observed, attributed primarily to a reduction in cortical 5-HT due to the effects of raphe autoreceptor inhibition. This study is the first demonstration of the feasibility of quantifying dynamic changes in 5-HT neurotransmission in the raphe and the cortex with PET. These results lend promise to the use of these serotonergic neuroimaging techniques to study neuropsychiatric disorders.
Collapse
Affiliation(s)
- Giampiero Giovacchini
- PET Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | | | |
Collapse
|
48
|
Kristiansen H, Elfving B, Plenge P, Pinborg LH, Gillings N, Knudsen GM. Binding characteristics of the 5-HT2A receptor antagonists altanserin and MDL 100907. Synapse 2005; 58:249-57. [PMID: 16206185 DOI: 10.1002/syn.20205] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To study the 5-HT(2A) receptors in the living human brain, using positron emission tomography (PET), two selective radiotracers are currently in use: [(18)F]altanserin and [(11)C]MDL 100907. It is, however, currently unknown to what extent data obtained with either tracer are directly comparable. The aim of this study was to compare binding characteristics of these two radiotracers in rat brain with respect to affinity (K(d)), receptor binding density (B(max)), binding potential (BP), and nonspecific binding. Further, binding kinetics, sensitivity towards competition with the endogenous transmitter serotonin, and the competitive/noncompetitive interaction between the two radioligands were evaluated. In addition, the selectivity of [(18)F]altanserin for the 5-HT(2A) receptor was assessed. The K(d) value of [(18)F]altanserin and [(3)H]MDL 100907 was in the order of 0.3 nM. B(max) in frontal cortex was 523 and 527 fmol/mg protein, respectively. The binding of [(18)F]altanserin was not influenced by blocking either the 5-HT(2B/2C) or the alpha(1)-adrenergic receptors. At 37 degrees C the association t(1/2) was 2.8 and 2.7 min and the dissociation t(1/2) was 11 and 13.5 min for [(18)F]altanserin and [(3)H]MDL 100907, respectively. Both radioligands were displaced by 5-HT, only at high concentrations; the K(i) value of 5-HT ranging between 650 and 3,300 nM. This indicates that binding of both radioligands in PET studies is not directly influenced by changes in endogenous 5-HT.Overall, the binding of [(18)F]altanserin and [(3)H]MDL 100907 to the 5-HT(2A) receptor was very comparable, showing selective high affinity binding in the subnanomolar range.
Collapse
Affiliation(s)
- Heidi Kristiansen
- Neurobiology Research Unit, University Hospital Rigshospitalet, Copenhagen, Denmark
| | | | | | | | | | | |
Collapse
|
49
|
Meyer PT, Elmenhorst D, Zilles K, Bauer A. Simplified quantification of cerebral A1 adenosine receptors using [18F]CPFPX and PET: Analyses based on venous blood sampling. Synapse 2005; 55:212-23. [PMID: 15668990 DOI: 10.1002/syn.20113] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
[(18)F]CPFPX was proposed as a novel ligand for in vivo quantification of cerebral A(1) adenosine receptors (A(1)AR) using positron emission tomography (PET). The present study investigates the applicability of non-invasive non-compartment analyses to quantify the [(18)F]CPFPX total distribution volume (DV(') (t)) without arterial blood sampling. Five healthy volunteers underwent dynamic PET (90 min) with arterial and venous blood sampling after [(18)F]CPFPX bolus injection. Area under curve (AUC) analysis and Logan's graphical analysis (GA) were performed employing venous blood samples as non-invasive analyses. AUC analysis without data extrapolation (AUC(r)) and venous GA were also applied on voxel-level to generate parametric images. A conventional two-tissue compartment model (2TCM) using arterial blood samples served as reference method. Regional DV(') (t) estimates provided by venous AUC and GA analyses and 2TCM demonstrated very high agreement (venous AUC vs. 2TCM: r(2) = 0.968, linear regression slope = 0.943; venous GA vs. 2TCM: r(2) = 0.972, slope = 0.906). Although on voxel-level the venous AUC(r) and GA analyses were affected by a slight negative bias, they were still very highly correlated with the 2TCM (voxel-wise venous AUC(r) vs. 2TCM: r(2) = 0.969, slope = 0.858; voxel-wise venous GA vs. 2TCM: r(2) = 0.959, slope = 0.867). The proposed non-invasive analysis methods (particularly venous GA) allow reliable quantification of human [(18)F]CPFPX PET studies. In populations with altered metabolic/kinetic properties, the applicability of venous sampling has to be separately verified. The applicability of [(18)F]CPFPX PET in basic and clinical neurosciences will be considerably enhanced by the avoidance of arterial blood sampling.
Collapse
Affiliation(s)
- Philipp T Meyer
- Institute of Medicine, Research Centre Juelich, 52425 Juelich, Germany.
| | | | | | | |
Collapse
|
50
|
Meyer PT, Bier D, Holschbach MH, Boy C, Olsson RA, Coenen HH, Zilles K, Bauer A. Quantification of cerebral A1 adenosine receptors in humans using [18F]CPFPX and PET. J Cereb Blood Flow Metab 2004; 24:323-33. [PMID: 15091113 DOI: 10.1097/01.wcb.0000110531.48786.9d] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Adenosine is an important neuromodulator. Basic cerebral effects of adenosine are exerted by the A1 adenosine receptor (A1AR), which is accessible in vivo by the novel ligand [F]8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine ([F]CPFPX) and positron emission tomography (PET). The present study investigates the applicability of kinetic models to describe the cerebral kinetics of [F]CPFPX in order to quantify A1AR density in vivo. Six healthy volunteers underwent dynamic PET scanning and arterial blood sampling after bolus injection of [F]CPFPX. For quantitative analysis, a standard two-tissue compartment model (2TCM) was compared with a one-tissue compartment model (1TCM) and Logan's graphical analysis (GA). The 2TCM described the cerebral kinetics of [F]CPFPX significantly better than the 1TCM (in all regions and subjects examined). The estimated values of the regional total distribution volumes (DVt) correlated strongly between the 2TCM and GA (linear regression r = 0.99, slope: 1.007). The DVt correlation between the 2TCM and the 1TCM was comparably high, but there was a significant bias towards lower DVt estimates given by the 1TCM (r: 0.99, slope: 0.929). It is concluded that a 2TCM satisfactorily accounts for the cerebral kinetics of [F]CPFPX. GA represents an attractive alternative method of analysis.
Collapse
Affiliation(s)
- Philipp T Meyer
- Institute of Medicine, Research Center Juelich, Juelich, Germany.
| | | | | | | | | | | | | | | |
Collapse
|