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Passannante R, Gómez-Vallejo V, Sagartzazu-Aizpurua M, Vignau Arsuaga L, Marco-Moreno P, Aldanondo G, Vallejo-Illarramendi A, Aguiar P, Cossío U, Martín A, Bergare J, Kingston L, Elmore CS, Morcillo MA, Ferrón P, Aizpurua JM, Llop J. Pharmacokinetic Evaluation of New Drugs Using a Multi-Labelling Approach and PET Imaging: Application to a Drug Candidate with Potential Application in Neuromuscular Disorders. Biomedicines 2023; 11:biomedicines11020253. [PMID: 36830793 PMCID: PMC9953224 DOI: 10.3390/biomedicines11020253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND OBJECTIVE The determination of pharmacokinetic properties of new chemical entities is a key step in the process of drug development. Positron emission tomography (PET) is an ideal technique to obtain both biodistribution and pharmacokinetic parameters of new compounds over a wide range of chemical modalities. Here, we use a multi-radionuclide/multi-position labelling approach to investigate distribution, elimination, and metabolism of a triazole-based FKBP12 ligand (AHK2) with potential application in neuromuscular disorders. METHODS Target engagement and stabilizing capacity of the drug candidate (AHK2) towards FKBP12-RyR was evaluated using competitive ligand binding and proximity ligation assays, respectively. Subsequently, AHK2 was labelled either with the positron emitter carbon-11 (11C) via 11C-methylation to yield both [11C]AHK2.1 and [11C]AHK2.2, or by palladium-catalysed reduction of the corresponding 5-iodotriazole derivative using 3H gas to yield [3H]AHK2. Metabolism was first investigated in vitro using liver microsomes. PET imaging studies in rats after intravenous (IV) administration at different doses (1 µg/Kg and 5 mg/Kg) were combined with determination of arterial blood time-activity curves (TACs) and analysis of plasma samples by high performance liquid chromatography (HPLC) to quantify radioactive metabolites. Arterial TACs were obtained in continuous mode by using an in-house developed system that enables extracorporeal blood circulation and continuous measurement of radioactivity in the blood. Pharmacokinetic parameters were determined by non-compartmental modelling of the TACs. RESULTS In vitro studies indicate that AHK2 binds to FKBP12 at the rapamycin-binding pocket, presenting activity as a FKBP12/RyR stabilizer. [11C]AHK2.1, [11C]AHK2.2 and [3H]AHK2 could be obtained in overall non-decay corrected radiochemical yields of 14 ± 2%, 15 ± 2% and 0.05%, respectively. Molar activities were 60-110 GBq/µmol, 68-122 GBq/µmol and 0.4-0.5 GBq/μmol, respectively. In vitro results showed that oxidation of the thioether group into sulfoxide, demethylation of the CH3O-Ar residue and demethylation of -N(CH3)2 were the main metabolic pathways. Fast metabolism was observed in vivo. Pharmacokinetic parameters obtained from metabolite-corrected arterial blood TACs showed a short half-life (12.6 ± 3.3 min). Dynamic PET imaging showed elimination via urine when [11C]AHK2.2 was administered, probably reflecting the biodistribution of [11C]methanol as the major metabolite. Contrarily, accumulation in the gastrointestinal track was observed after administration of [11C]AKH2.1. CONCLUSIONS AHK2 binds to FKBP12 at the rapamycin-binding pocket, presenting activity as a FKBP12/RyR stabilizer. Studies performed with the 3H- and 11C-labelled FKBP12/RyR stabilizer AHK2 confirm fast blood clearance, linear pharmacokinetics and rapid metabolism involving oxidation of the sulfide and amine moieties and oxidative demethylation of the CH3-O-Ar and tertiary amine groups as the main pathways. PET studies suggest that knowledge about metabolic pathways is paramount to interpret images.
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Affiliation(s)
- Rossana Passannante
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 San Sebastián, Spain
| | - Vanessa Gómez-Vallejo
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 San Sebastián, Spain
| | | | - Laura Vignau Arsuaga
- Departamento de Química Orgánica-I, UPV/EHU-University of the Basque Country, 20018 San Sebastián, Spain
| | - Pablo Marco-Moreno
- Group of Neuromuscular Diseases, Biodonostia Health Research Institute, 20014 San Sebastián, Spain
| | - Garazi Aldanondo
- Group of Neuromuscular Diseases, Biodonostia Health Research Institute, 20014 San Sebastián, Spain
- Deusto Physical TherapIker, Physical Therapy Department, Faculty of Health Sciences, University of Deusto, 20012 San Sebastián, Spain
| | - Ainara Vallejo-Illarramendi
- Group of Neuromuscular Diseases, Biodonostia Health Research Institute, 20014 San Sebastián, Spain
- Group of Neuroscience, Department of Pediatrics, Hospital Donostia, UPV/EHU, 20014 San Sebastián, Spain
| | - Pablo Aguiar
- Molecular Imaging Group, IDIS, CIMUS, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Unai Cossío
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 San Sebastián, Spain
| | - Abraham Martín
- Ikerbasque, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
- Laboratory of Neuroimaging and Biomarkers of Inflammation, Achucarro Basque Center for Neuroscience, Science Park UPV/EHU, Sede Building B, Sarriena, 48940 Leioa, Spain
| | - Jonas Bergare
- Early Chemical Development, Pharmaceutical Sciences R&D, AstraZeneca, 431 83 Gothenburg, Sweden
| | - Lee Kingston
- Early Chemical Development, Pharmaceutical Sciences R&D, AstraZeneca, 431 83 Gothenburg, Sweden
| | - Charles S. Elmore
- Early Chemical Development, Pharmaceutical Sciences R&D, AstraZeneca, 431 83 Gothenburg, Sweden
| | | | - Pablo Ferrón
- Miramoon Pharma S.L., Avda Tolosa-72, 20018 San Sebastián, Spain
| | - Jesus M. Aizpurua
- Departamento de Química Orgánica-I, UPV/EHU-University of the Basque Country, 20018 San Sebastián, Spain
| | - Jordi Llop
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 San Sebastián, Spain
- Correspondence:
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Gu Z, Chen H, Zhao H, Yang W, Song Y, Li X, Wang Y, Du D, Liao H, Pan W, Li X, Gao Y, Han H, Tong Z. New insight into brain disease therapy: nanomedicines-crossing blood-brain barrier and extracellular space for drug delivery. Expert Opin Drug Deliv 2022; 19:1618-1635. [PMID: 36285632 DOI: 10.1080/17425247.2022.2139369] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
INTRODUCTION Brain diseases including brain tumor, Alzheimer's disease, Parkinson's disease, etc. are difficult to treat. The blood-brain barrier (BBB) is a major obstacle for drug delivery into the brain. Although nano-package and receptor-mediated delivery of nanomedicine markedly increases BBB penetration, it yet did not extensively improve clinical cure rate. Recently, brain extracellular space (ECS) and interstitial fluid (ISF) drainage in ECS have been found to determine whether a drug dissolved in ISF can reach its target cells. Notably, an increase in tortuosity of ECS associated with slower ISF drainage induced by the accumulated harmful substances, such as: amyloid-beta (Aβ), α-synuclein, and metabolic wastes, causes drug delivery failure. AREAS COVERED The methods of nano-package and receptor-mediated drug delivery and the penetration efficacy of nanomedicines across BBB and ECS are assessed. EXPERT OPINION Invasive delivering drug via ECS and noninvasive near-infrared photo-sensitive nanomedicines may provide a promising benefit to patients with brain disease.
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Affiliation(s)
- Ziqi Gu
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Haishu Chen
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Han Zhao
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Wanting Yang
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Yilan Song
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Xiang Li
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Yang Wang
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China.,Department of Radiology, Peking University Third Hospital, Beijing, China
| | - Dan Du
- Department of Radiology, Peking University Third Hospital, Beijing, China.,Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China.,Beijing Key Laboratory of Magnetic Resonance Imaging Devices and Technology, Peking University Third Hospital, Beijing, China
| | - Haikang Liao
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Wenhao Pan
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Xi Li
- The Affiliated Kangning Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yajuan Gao
- Department of Radiology, Peking University Third Hospital, Beijing, China.,NMPA key Laboratory for Evaluation of Medical Imaging Equipment and Technique, Beijing, China
| | - Hongbin Han
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China.,Department of Radiology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging Devices and Technology, Peking University Third Hospital, Beijing, China.,Peking University Shenzhen Graduate School, Shenzhen, China
| | - Zhiqian Tong
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Oujiang Laboratory, School of Mental Health, Wenzhou Medical University, Wenzhou, China.,The Affiliated Kangning Hospital of Wenzhou Medical University, Wenzhou, China
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Veronese M, Tuosto M, Marques TR, Howes O, Pascual B, Yu M, Masdeu JC, Turkheimer F, Bertoldo A, Zanotti-Fregonara P. Parametric Mapping for TSPO PET Imaging with Spectral Analysis Impulsive Response Function. Mol Imaging Biol 2021; 23:560-571. [PMID: 33475944 PMCID: PMC8277653 DOI: 10.1007/s11307-020-01575-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/27/2020] [Accepted: 12/21/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to investigate the use of spectral analysis (SA) for voxel-wise analysis of TSPO PET imaging studies. TSPO PET quantification is methodologically complicated by the heterogeneity of TSPO expression and its cell-dependent modulation during neuroinflammatory response. Compartmental models to account for this complexity exist, but they are unreliable at the high noise typical of voxel data. On the contrary, SA is noise-robust for parametric mapping and provides useful information about tracer kinetics with a free compartmental structure. PROCEDURES SA impulse response function (IRF) calculated at 90 min after tracer injection was used as main parameter of interest in 3 independent PET imaging studies to investigate its sensitivity to (1) a TSPO genetic polymorphism (rs6971) known to affect tracer binding in a cross-sectional analysis of healthy controls scanned with [11C]PBR28 PET; (2) TSPO density with [11C]PBR28 in a competitive blocking study with a TSPO blocker, XBD173; and (3) the higher affinity of a second radiotracer for TSPO, by using data from a head-to-head comparison between [11C]PBR28 and [11C]ER176 scans. RESULTS SA-IRF produced parametric maps of visually good quality. These were sensitive to TSPO genotype (mean relative difference between high- and mixed-affinity binders = 25 %) and TSPO availability (mean signal displacement after 90 mg oral administration of XBD173 = 39 %). Regional averages of voxel-wise IRF estimates were strongly associated with regional total distribution volume (VT) estimated with a 2-tissue compartmental model with vascular compartment (Pearson's r = 0.86 ± 0.11) but less strongly with standard 2TCM-VT (Pearson's r = 0.76 ± 0.32). Finally, SA-IRF estimates for [11C]ER176 were significantly higher than [11C]PBR28 ones, consistent with the higher amount of specific binding of the former tracer. CONCLUSIONS SA-IRF can be used for voxel-wise quantification of TSPO PET data because it generates high-quality parametric maps, it is sensitive to TSPO availability and genotype, and it accounts for the complexity of TSPO tracer kinetics with no additional assumptions.
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Affiliation(s)
- Mattia Veronese
- Department of Neuroimaging, IoPPN, King's College London, London, UK.
| | - Marcello Tuosto
- Department of Information Engineering, Padova University, Padova, Italy
| | - Tiago Reis Marques
- Department of Psychosis Studies, IoPPN, King's College London, London, UK
| | - Oliver Howes
- Department of Psychosis Studies, IoPPN, King's College London, London, UK
- MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK
| | - Belen Pascual
- Nantz National Alzheimer Center and Houston Methodist Research Neurological Institute, and Weill Cornell Medicine, 6670 Bertner Ave, Houston, TX, 77030, USA
| | - Meixiang Yu
- Nantz National Alzheimer Center and Houston Methodist Research Neurological Institute, and Weill Cornell Medicine, 6670 Bertner Ave, Houston, TX, 77030, USA
| | - Joseph C Masdeu
- Nantz National Alzheimer Center and Houston Methodist Research Neurological Institute, and Weill Cornell Medicine, 6670 Bertner Ave, Houston, TX, 77030, USA
| | | | - Alessandra Bertoldo
- Department of Information Engineering, Padova University, Padova, Italy
- Padova Neuroscience Centre, Padova University, Padova, Italy
| | - Paolo Zanotti-Fregonara
- Nantz National Alzheimer Center and Houston Methodist Research Neurological Institute, and Weill Cornell Medicine, 6670 Bertner Ave, Houston, TX, 77030, USA
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Kato H, Okuno T, Isohashi K, Koda T, Shimizu M, Mochizuki H, Nakatsuji Y, Hatazawa J. Astrocyte metabolism in multiple sclerosis investigated by 1-C-11 acetate PET. J Cereb Blood Flow Metab 2021; 41:369-379. [PMID: 32169013 PMCID: PMC7812519 DOI: 10.1177/0271678x20911469] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study was aimed at evaluating the metabolism of reactive astrocytes in the brains of patients with multiple sclerosis by quantitative 1-C-11 acetate positron emission tomography (PET). Magnetic resonance imaging and 1-C-11 quantitative PET were performed in eight patients with multiple sclerosis and 10 normal control subjects. The efflux rate (k2) of 1-C-11 acetate, which reportedly reflects the metabolic rate of 1-C-11 acetate, was calculated based on the one-tissue compartmental model. Fractional anisotropy was also determined to evaluate the integrity of the neuronal tracts. The values of k2 in the patients with multiple sclerosis were significantly higher than those in the normal control subjects, in both the white matter (p = 0.003) and the gray matter (p = 0.02). In addition, the white matter/gray matter ratio of k2 was significantly higher in the multiple sclerosis patients than in the normal control subjects (p = 0.02). Voxel-based statistical analysis revealed most prominent increase in k2 in the neuronal fiber tracts, as well as decrease in fractional anisotropy in them in the multiple sclerosis patients. The present study clarified that the pathological changes associated with astrocytic reactivation in multiple sclerosis patients could be visualized by quantitative 1-C-11 acetate PET.
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Affiliation(s)
- Hiroki Kato
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tatsusada Okuno
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kayako Isohashi
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Toru Koda
- Department of Medical Innovation, Osaka University Hospital Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Mikito Shimizu
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yuji Nakatsuji
- Department of Neurology, Toyama University Hospital, Toyama, Japan
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
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Meyer J. Novel Phenotypes Detectable with PET in Mood Disorders: Elevated Monoamine Oxidase A and Translocator Protein Level. PET Clin 2018; 12:361-371. [PMID: 28576173 DOI: 10.1016/j.cpet.2017.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
As a result of high prevalence and high rates of treatment resistance, major depressive disorder has become the leading cause of death and disability in moderate-income to high-income nations. Poor targeting of phenotypes is a plausible reason for treatment resistance and PET imaging offers a unique role to identify phenotypes. Both increased monoamine oxidase A binding and greater translocator protein 18 kDa binding occur throughout the gray matter during major depressive episodes, including affect-modulating brain regions such as the prefrontal and anterior cingulate cortex, and are detectable with advanced radioligand technology for both of these targets.
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Affiliation(s)
- Jeffrey Meyer
- Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario M5T1R8, Canada.
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Golla SSV, Adriaanse SM, Yaqub M, Windhorst AD, Lammertsma AA, van Berckel BNM, Boellaard R. Model selection criteria for dynamic brain PET studies. EJNMMI Phys 2017; 4:30. [PMID: 29209862 PMCID: PMC5716967 DOI: 10.1186/s40658-017-0197-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 11/23/2017] [Indexed: 12/04/2022] Open
Abstract
Background Several criteria exist to identify the optimal model for quantification of tracer kinetics. The purpose of this study was to evaluate the correspondence in kinetic model preference identification for brain PET studies among five model selection criteria: Akaike Information Criterion (AIC), AIC unbiased (AICC), model selection criterion (MSC), Schwartz Criterion (SC), and F-test. Materials and Methods Six tracers were evaluated: [11C]FMZ, [11C]GMOM, [11C]PK11195, [11C]Raclopride, [18F]FDG, and [11C]PHT, including data from five subjects per tracer. Time activity curves (TACs) were analysed using six plasma input models: reversible single-tissue model (1T2k), irreversible two-tissue model (2T3k), and reversible two-tissue model (2T4k), all with and without blood volume fraction parameter (VB). For each tracer and criterion, the percentage of TACs preferring a certain model was calculated. Results For all radiotracers, strong agreement was seen across the model selection criteria. The F-test was considered as the reference, as it is a frequently used hypothesis test. The F-test confirmed the AIC preferred model in 87% of all cases. The strongest (but minimal) disagreement across regional TACs was found when comparing AIC with AICC. Despite these regional discrepancies, same preferred kinetic model was obtained using all criteria, with an exception of one FMZ subject. Conclusion In conclusion, all five model selection criteria resulted in similar conclusions with only minor differences that did not affect overall model selection. Electronic supplementary material The online version of this article (10.1186/s40658-017-0197-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandeep S V Golla
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands.
| | - Sofie M Adriaanse
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands
| | - Maqsood Yaqub
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands
| | - Bart N M van Berckel
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine, VU University Medical Center, P.O. 7057, 1007, MB, Amsterdam, The Netherlands.,Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Spectral Analysis of Dynamic PET Studies: A Review of 20 Years of Method Developments and Applications. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:7187541. [PMID: 28050197 PMCID: PMC5165231 DOI: 10.1155/2016/7187541] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 10/27/2016] [Indexed: 11/17/2022]
Abstract
In Positron Emission Tomography (PET), spectral analysis (SA) allows the quantification of dynamic data by relating the radioactivity measured by the scanner in time to the underlying physiological processes of the system under investigation. Among the different approaches for the quantification of PET data, SA is based on the linear solution of the Laplace transform inversion whereas the measured arterial and tissue time-activity curves of a radiotracer are used to calculate the input response function of the tissue. In the recent years SA has been used with a large number of PET tracers in brain and nonbrain applications, demonstrating that it is a very flexible and robust method for PET data analysis. Differently from the most common PET quantification approaches that adopt standard nonlinear estimation of compartmental models or some linear simplifications, SA can be applied without defining any specific model configuration and has demonstrated very good sensitivity to the underlying kinetics. This characteristic makes it useful as an investigative tool especially for the analysis of novel PET tracers. The purpose of this work is to offer an overview of SA, to discuss advantages and limitations of the methodology, and to inform about its applications in the PET field.
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Rotstein BH, Liang SH, Placzek MS, Hooker JM, Gee AD, Dollé F, Wilson AA, Vasdev N. (11)C[double bond, length as m-dash]O bonds made easily for positron emission tomography radiopharmaceuticals. Chem Soc Rev 2016; 45:4708-26. [PMID: 27276357 PMCID: PMC5000859 DOI: 10.1039/c6cs00310a] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The positron-emitting radionuclide carbon-11 ((11)C, t1/2 = 20.3 min) possesses the unique potential for radiolabeling of any biological, naturally occurring, or synthetic organic molecule for in vivo positron emission tomography (PET) imaging. Carbon-11 is most often incorporated into small molecules by methylation of alcohol, thiol, amine or carboxylic acid precursors using [(11)C]methyl iodide or [(11)C]methyl triflate (generated from [(11)C]carbon dioxide or [(11)C]methane). Consequently, small molecules that lack an easily substituted (11)C-methyl group are often considered to have non-obvious strategies for radiolabeling and require a more customized approach. [(11)C]Carbon dioxide itself, [(11)C]carbon monoxide, [(11)C]cyanide, and [(11)C]phosgene represent alternative reactants to enable (11)C-carbonylation. Methodologies developed for preparation of (11)C-carbonyl groups have had a tremendous impact on the development of novel PET tracers and provided key tools for clinical research. (11)C-Carbonyl radiopharmaceuticals based on labeled carboxylic acids, amides, carbamates and ureas now account for a substantial number of important imaging agents that have seen translation to higher species and clinical research of previously inaccessible targets, which is a testament to the creativity, utility and practicality of the underlying radiochemistry.
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Affiliation(s)
| | - Steven H Liang
- Massachusetts General Hospital, Harvard Medical School, Boston, USA.
| | - Michael S Placzek
- Athinoula A. Martinos Center for Biomedical Imaging, MGH, HMS, Charlestown, USA and McLean Hospital, Belmont, USA
| | - Jacob M Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, MGH, HMS, Charlestown, USA
| | | | - Frédéric Dollé
- CEA - Institut d'imagerie biomédicale, Service hospitalier Frédéric Joliot, Université Paris-Saclay, Orsay, France
| | - Alan A Wilson
- Centre for Addiction and Mental Health, Toronto, Canada
| | - Neil Vasdev
- Massachusetts General Hospital, Harvard Medical School, Boston, USA.
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Gunn RN, Slifstein M, Searle GE, Price JC. Quantitative imaging of protein targets in the human brain with PET. Phys Med Biol 2015; 60:R363-411. [DOI: 10.1088/0031-9155/60/22/r363] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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10
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Maschauer S, Haller A, Riss PJ, Kuwert T, Prante O, Cumming P. Specific binding of [(18)F]fluoroethyl-harmol to monoamine oxidase A in rat brain cryostat sections, and compartmental analysis of binding in living brain. J Neurochem 2015; 135:908-17. [PMID: 26386360 DOI: 10.1111/jnc.13370] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 09/08/2015] [Accepted: 09/10/2015] [Indexed: 11/28/2022]
Abstract
We investigated [(18)F]fluoroethyl-harmol ([(18)F]FEH) as a reversible and selective ligand for positron emission tomography (PET) studies of monoamine oxidase A (MAO-A). Binding of [(18)F]FEH in rat brain cryostat sections indicated high affinity (KD = 3 nM), and density (Bmax; 600 pmol/g). The plasma free fraction was 45%, and untransformed parent constituted only 13% of plasma radioactivity at 10 min after injection. Compartmental analysis of PET recordings in pargyline-treated rats showed high permeability to brain (K1; 0.32 mL/g/min) and slow washout (k2; 0.024/min), resulting in a uniformly high equilibrium distribution volume (VD; 20 mL/g). Using this VD to estimate unbound ligand in brain of untreated rats, the binding potential ranged from 4.2 in cerebellum to 7.2 in thalamus. We also calculated maps of rats receiving [(18)F]FEH at a range of specific activities, and then estimated saturation binding parameters in the living brain. In thalamus, striatum and frontal cortex KD was globally close to 300 nM and Bmax was close to 1600 pmol/g; the 100-fold discrepancy in affinity suggests a very low free fraction for [(18)F]FEH in the living brain. Based on a synthesis of findings, we calculate the endogenous dopamine concentration to be 0.4 μM in the striatal compartment containing MAO-A, thus unlikely to exert competition against [(18)F]FEH binding in vivo. In summary, [(18)F]FEH has good properties for the detection of MAO-A in the rat brain by PET, and may present logistic advantages for clinical research at centers lacking a medical cyclotron. We made a compartmental analysis of [(18)F]fluoroethylharmol ([(18)F]FEH) binding to monoamine oxidase A (MAO-A) in living rat brain and estimated the saturation binding parameters from the binding potential (BPND). The Bmax was of comparable magnitude to that in vitro, but with apparent affinity (300 nM), it was 100-fold lower in vivo. PET imaging with [(18) F]FEH is well suited for quantitation of MAO-A in living brain.
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Affiliation(s)
- Simone Maschauer
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Adelina Haller
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Patrick J Riss
- Department of Chemistry, Universitetet i Oslo & Norsk Medisinisk Syklotronsenter AS, Oslo, Norway
| | - Torsten Kuwert
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Olaf Prante
- Laboratory of Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University, Erlangen, Germany
| | - Paul Cumming
- Department of Neuroscience and Pharmacology, Copenhagen University, Copenhagen, Denmark.,Department of Neuropsychiatry and Psychosomatic Medicine, OUS-Rikshospitalet, Oslo, Norway
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Imaging of monoamine oxidase-A in the human brain with [11C]befloxatone: quantification strategies and correlation with mRNA transcription maps. Nucl Med Commun 2015; 35:1254-61. [PMID: 25185897 DOI: 10.1097/mnm.0000000000000196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION [C]Befloxatone is a highly specific, reversible, and selective radioligand for brain PET imaging of monoamine oxidase-A and can be quantified by a two-tissue compartment model (2TCM) and an arterial input function. The aims of the present study were the following: (a) to assess whether in-vivo protein concentration, as measured by [C]befloxatone total distribution volume (VT), is correlated with post-mortem mRNA expression; (b) to replicate in a population of tobacco smokers the results of a recent study on healthy nonsmokers, which showed that spectral analysis (SA) provides a highly accurate estimation of [C]befloxatone-VT at the voxel level; and (c) to validate the use of an input function that would not require arterial sampling. MATERIALS AND METHODS Healthy male nonsmokers (n=7) and smokers (n=8) were imaged with PET and [C]befloxatone. Binding was quantified at the regional and voxel level with the Logan plot, multilinear analysis (MA1), and SA. VT values were compared with the reference values obtained by 2TCM at the regional level. [C]Befloxatone binding was compared with mRNA transcription maps from the Allen Human Brain Atlas. A less-invasive input function was obtained with a population-based input function (PBIF) scaled with arterialized venous samples. RESULTS mRNA expression was highly correlated with in-vivo 2TCM-VT values both for nonsmokers (R=0.873; P<0.0001) and for smokers (R=0.851; P<0.0001). At the regional level, both Logan and MA1 showed a moderate negative bias (-5 to -10%) compared with the reference VT values. With the exception of a single outlying individual, SA showed little bias and variability (+4.4±3.5%). Although variability was higher than at the regional level, SA provided the most accurate VT estimations at the voxel level: all but one participant had an error of less than 20%. Parametric Logan and MA1 analyses gave highly biased or unusable results. PBIF provided good results in all participants in whom the arterialization of venous blood was successful (all errors of about 10% or less). CONCLUSION [C]Befloxatone binding is strongly correlated with the values of mRNA transcription measured in post-mortem brains. At the voxel level, SA is the best available choice for [C]befloxatone quantification, although a higher variability must be expected. When an arterial input function is not technically feasible, a PBIF scaled with arterialized venous samples may provide an acceptable alternative, provided an optimal arterialization can be achieved.
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[11C]befloxatone distribution is well correlated to monoamine oxidase A protein levels in the human brain. J Cereb Blood Flow Metab 2014; 34:1951-2. [PMID: 25227605 PMCID: PMC4269741 DOI: 10.1038/jcbfm.2014.157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 08/17/2014] [Accepted: 08/20/2014] [Indexed: 11/09/2022]
Abstract
[(11)C]befloxatone is a positron emission tomography radioligand to image monoamine oxidase A (MAO-A) in the brain, which has been used in preclinical studies and in clinical protocols. However, a recent study found that [(11)C]befloxatone binding potential (k(3)/k(4)) has a poor correlation with MAO-A protein levels measured in the human brain. We here show that this poor correlation only depends on the choice of the parameter when performing kinetic modeling. In particular, the total volume of distribution of [(11)C]befloxatone shows a tight correlation with both protein and mRNA levels of MAO-A in the human brain.
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Cumming P, Skaper D, Kuwert T, Maschauer S, Prante O. Detection of monoamine oxidase a in brain of living rats with [18F]fluoroethyl-harmol PET. Synapse 2014; 69:57-9. [DOI: 10.1002/syn.21785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/25/2014] [Accepted: 09/11/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Paul Cumming
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
- Department of Neuroscience and Pharmacology; Copenhagen University; Copenhagen Denmark
| | - Dirk Skaper
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
| | - Torsten Kuwert
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
| | - Simone Maschauer
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
| | - Olaf Prante
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry; Friedrich Alexander University Erlangen-Nürnberg (FAU); Erlangen Germany
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Deriving physiological information from PET images: from SUV to compartmental modelling. Clin Transl Imaging 2014. [DOI: 10.1007/s40336-014-0067-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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