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Bagnato F, Sati P, Hemond CC, Elliott C, Gauthier SA, Harrison DM, Mainero C, Oh J, Pitt D, Shinohara RT, Smith SA, Trapp B, Azevedo CJ, Calabresi PA, Henry RG, Laule C, Ontaneda D, Rooney WD, Sicotte NL, Reich DS, Absinta M. Imaging chronic active lesions in multiple sclerosis: a consensus statement. Brain 2024; 147:2913-2933. [PMID: 38226694 PMCID: PMC11370808 DOI: 10.1093/brain/awae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 11/21/2023] [Accepted: 12/08/2023] [Indexed: 01/17/2024] Open
Abstract
Chronic active lesions (CAL) are an important manifestation of chronic inflammation in multiple sclerosis and have implications for non-relapsing biological progression. In recent years, the discovery of innovative MRI and PET-derived biomarkers has made it possible to detect CAL, and to some extent quantify them, in the brain of persons with multiple sclerosis, in vivo. Paramagnetic rim lesions on susceptibility-sensitive MRI sequences, MRI-defined slowly expanding lesions on T1-weighted and T2-weighted scans, and 18-kDa translocator protein-positive lesions on PET are promising candidate biomarkers of CAL. While partially overlapping, these biomarkers do not have equivalent sensitivity and specificity to histopathological CAL. Standardization in the use of available imaging measures for CAL identification, quantification and monitoring is lacking. To fast-forward clinical translation of CAL, the North American Imaging in Multiple Sclerosis Cooperative developed a consensus statement, which provides guidance for the radiological definition and measurement of CAL. The proposed manuscript presents this consensus statement, summarizes the multistep process leading to it, and identifies the remaining major gaps in knowledge.
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Affiliation(s)
- Francesca Bagnato
- Neuroimaging Unit, Neuroimmunology Division, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
- Department of Neurology, Nashville VA Medical Center, Tennessee Valley Healthcare System, Nashville, TN 37212, USA
| | - Pascal Sati
- Neuroimaging Program, Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Christopher C Hemond
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | | | - Susan A Gauthier
- Department of Neurology, Weill Cornell Medicine, New York, NY 10021, USA
| | - Daniel M Harrison
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Neurology, Baltimore VA Medical Center, VA Maryland Healthcare System, Baltimore, MD 21201, USA
| | - Caterina Mainero
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jiwon Oh
- Division of Neurology, St. Michael’s Hospital, University of Toronto, Toronto, ON M5S, Canada
| | - David Pitt
- Department of Neurology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Russell T Shinohara
- Penn Statistics in Imaging and Visualization Endeavor, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Biomedical Image Computing and Analytics, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Seth A Smith
- Department of Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37235, USA
| | - Bruce Trapp
- Department on Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Christina J Azevedo
- Department of Neurology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90007, USA
| | - Peter A Calabresi
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Roland G Henry
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Cornelia Laule
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Daniel Ontaneda
- Mellen Center for Multiple Sclerosis, Cleveland Clinic, Cleveland, OH 44195, USA
| | - William D Rooney
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR 97239, USA
| | - Nancy L Sicotte
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Martina Absinta
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Translational Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology, Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, 20132, Italy
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Giladi M, Montgomery AP, Kassiou M, Danon JJ. Structure-based drug design for TSPO: Challenges and opportunities. Biochimie 2024; 224:41-50. [PMID: 38782353 DOI: 10.1016/j.biochi.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/27/2024] [Accepted: 05/21/2024] [Indexed: 05/25/2024]
Abstract
The translocator protein 18 kDa (TSPO) is an evolutionarily conserved mitochondrial transmembrane protein implicated in various neuropathologies and inflammatory conditions, making it a longstanding diagnostic and therapeutic target of interest. Despite the development of various classes of TSPO ligand chemotypes, and the elucidation of bacterial and non-human mammalian experimental structures, many unknowns exist surrounding its differential structural and functional features in health and disease. There are several limitations associated with currently used computational methodologies for modelling the native structure and ligand-binding behaviour of this enigmatic protein. In this perspective, we provide a critical analysis of the developments in the uses of these methods, outlining their uses, inherent limitations, and continuing challenges. We offer suggestions of unexplored opportunities that exist in the use of computational methodologies which offer promise for enhancing our understanding of the TSPO.
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Affiliation(s)
- Mia Giladi
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia
| | | | - Michael Kassiou
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia.
| | - Jonathan J Danon
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia.
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Chen P, Ding N, Pan D, Chen X, Li S, Luo Y, Chen Z, Xu Y, Zhu X, Wang K, Zou W. PET imaging for the early evaluation of ocular inflammation in diabetic rats by using [ 18F]-DPA-714. Exp Eye Res 2024; 245:109986. [PMID: 38945519 DOI: 10.1016/j.exer.2024.109986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/02/2024]
Abstract
Ocular complications of diabetes mellitus (DM) are the leading cause of vision loss. Ocular inflammation often occurs in the early stage of DM; however, there are no proven quantitative methods to evaluate the inflammatory status of eyes in DM. The 18 kDa translocator protein (TSPO) is an evolutionarily conserved cholesterol binding protein localized in the outer mitochondrial membrane. It is a biomarker of activated microglia/macrophages; however, its role in ocular inflammation is unclear. In this study, fluorine-18-DPA-714 ([18F]-DPA-714) was evaluated as a specific TSPO probe by cell uptake, cell binding assays and micro positron emission tomography (microPET) imaging in both in vitro and in vivo models. Primary microglia/macrophages (PMs) extracted from the cornea, retina, choroid or sclera of neonatal rats with or without high glucose (50 mM) treatment were used as the in vitro model. Sprague-Dawley (SD) rats that received an intraperitoneal administration of streptozotocin (STZ, 60 mg/kg once) were used as the in vivo model. Increased cell uptake and high binding affinity of [18F]-DPA-714 were observed in primary PMs under hyperglycemic stress. These findings were consistent with cellular morphological changes, cell activation, and TSPO up-regulation. [18F]-DPA-714 PET imaging and biodistribution in the eyes of DM rats revealed that inflammation initiates in microglia/macrophages in the early stages (3 weeks and 6 weeks), corresponding with up-regulated TSPO levels. Thus, [18F]-DPA-714 microPET imaging may be an effective approach for the early evaluation of ocular inflammation in DM.
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Affiliation(s)
- Peng Chen
- Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Jintan Affiliated Hospital of Jiangsu University, Changzhou, Jiangsu, China
| | - Nannan Ding
- Department of Ophthalmology, Wuxi No.2 People's Hospital, Jiangnan University Medical Center (JUMC), Wuxi, Jiangsu, China; Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China
| | - Donghui Pan
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xuelian Chen
- Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, PuNan Branch of Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - ShiYi Li
- Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Jingjiang People's Hospital Affiliated to Yangzhou University, Taizhou, Jiangsu, China
| | - Yidan Luo
- Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China
| | - Ziqing Chen
- Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China
| | - Yuping Xu
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xue Zhu
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ke Wang
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Wenjun Zou
- Department of Ophthalmology, Wuxi No.2 People's Hospital, Jiangnan University Medical Center (JUMC), Wuxi, Jiangsu, China; Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China.
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Lee N, Choi JY, Ryu YH. The development status of PET radiotracers for evaluating neuroinflammation. Nucl Med Mol Imaging 2024; 58:160-176. [PMID: 38932754 PMCID: PMC11196502 DOI: 10.1007/s13139-023-00831-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 06/28/2024] Open
Abstract
Neuroinflammation is associated with the pathophysiologies of neurodegenerative and psychiatric disorders. Evaluating neuroinflammation using positron emission tomography (PET) plays an important role in the early diagnosis and determination of proper treatment of brain diseases. To quantify neuroinflammatory responses in vivo, many PET tracers have been developed using translocator proteins, imidazole-2 binding site, cyclooxygenase, monoamine oxidase-B, adenosine, cannabinoid, purinergic P2X7, and CSF-1 receptors as biomarkers. In this review, we introduce the latest developments in PET tracers that can image neuroinflammation, focusing on clinical trials, and further consider their current implications.
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Affiliation(s)
- Namhun Lee
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
| | - Jae Yong Choi
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
- Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul, Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Knyzeliene A, MacAskill MG, Alcaide-Corral CJ, Morgan TEF, Henry MC, Lucatelli C, Pimlott SL, Sutherland A, Tavares AAS. [ 18F]LW223 has low non-displaceable binding in murine brain, enabling high sensitivity TSPO PET imaging. J Cereb Blood Flow Metab 2024; 44:397-406. [PMID: 37795635 PMCID: PMC10870961 DOI: 10.1177/0271678x231205661] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 09/01/2023] [Accepted: 09/09/2023] [Indexed: 10/06/2023]
Abstract
Neuroinflammation is associated with a number of brain diseases, making it a common feature of cerebral pathology. Among the best-known biomarkers for neuroinflammation in Positron Emission Tomography (PET) research is the 18 kDa translocator protein (TSPO). This study aims to investigate the binding kinetics of a novel TSPO PET radiotracer, [18F]LW223, in mice and specifically assess its volume of non-displaceable binding (VND) in brain as well as investigate the use of simplified analysis approaches for quantification of [18F]LW223 PET data. Adult male mice were injected with [18F]LW223 and varying concentrations of LW223 (0.003-0.55 mg/kg) to estimate VND of [18F]LW223. Dynamic PET imaging with arterial input function studies and radiometabolite studies were conducted. Simplified quantification methods, standard uptake values (SUV) and apparent volume of distribution (VTapp), were investigated. [18F]LW223 had low VND in the brain (<10% of total binding) and low radiometabolism (∼15-20%). The 2-tissue compartment model provided the best fit for [18F]LW223 PET data, although its correlation with SUV90-120min or VTapp allowed for [18F]LW223 brain PET data quantification in healthy animals while using simpler experimental and analytical approaches. [18F]LW223 has the required properties to become a successful TSPO PET radiotracer.
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Affiliation(s)
- Agne Knyzeliene
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | - Mark G MacAskill
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | - Carlos J Alcaide-Corral
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | - Timaeus EF Morgan
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | | | | | - Sally L Pimlott
- West of Scotland PET Centre, Greater Glasgow and Clyde NHS Trust, Glasgow, UK
| | | | - Adriana AS Tavares
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
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Neumann KD, Broshek DK, Newman BT, Druzgal TJ, Kundu BK, Resch JE. Concussion: Beyond the Cascade. Cells 2023; 12:2128. [PMID: 37681861 PMCID: PMC10487087 DOI: 10.3390/cells12172128] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Sport concussion affects millions of athletes each year at all levels of sport. Increasing evidence demonstrates clinical and physiological recovery are becoming more divergent definitions, as evidenced by several studies examining blood-based biomarkers of inflammation and imaging studies of the central nervous system (CNS). Recent studies have shown elevated microglial activation in the CNS in active and retired American football players, as well as in active collegiate athletes who were diagnosed with a concussion and returned to sport. These data are supportive of discordance in clinical symptomology and the inflammatory response in the CNS upon symptom resolution. In this review, we will summarize recent advances in the understanding of the inflammatory response associated with sport concussion and broader mild traumatic brain injury, as well as provide an outlook for important research questions to better align clinical and physiological recovery.
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Affiliation(s)
- Kiel D. Neumann
- Department of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA;
| | - Donna K. Broshek
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA 22903, USA;
| | - Benjamin T. Newman
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA; (B.T.N.); (T.J.D.); (B.K.K.)
| | - T. Jason Druzgal
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA; (B.T.N.); (T.J.D.); (B.K.K.)
| | - Bijoy K. Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA; (B.T.N.); (T.J.D.); (B.K.K.)
| | - Jacob E. Resch
- Department of Kinesiology, University of Virginia, Charlottesville, VA 22903, USA
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Tan Z, Haider A, Zhang S, Chen J, Wei J, Liao K, Li G, Wei H, Dong C, Ran W, Li Y, Li Y, Rong J, Li Y, Liang SH, Xu H, Wang L. Quantitative assessment of translocator protein (TSPO) in the non-human primate brain and clinical translation of [ 18F]LW223 as a TSPO-targeted PET radioligand. Pharmacol Res 2023; 189:106681. [PMID: 36746361 DOI: 10.1016/j.phrs.2023.106681] [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] [Received: 12/07/2022] [Revised: 01/12/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Translocator protein 18 kDa (TSPO) positron emission tomography (PET) can be harnessed for the non-invasive detection of macrophage-driven inflammation. [18F]LW223, a newly reported TSPO PET tracer which was insensitive to rs6971 polymorphism, showed favorable performance characteristics in a recent imaging study involving a rat myocardial infarction model. To enable quantitative neuroimaging with [18F]LW223, we conducted kinetic analysis in the non-human primate (NHP) brain. Further, we sought to assess the utility of [18F]LW223-based TSPO imaging in a first-in-human study. METHODS Radiosynthesis of [18F]LW223 was accomplished on an automated module, whereas molar activities, stability in formulation, lipophilicity and unbound free fraction (fu) of the probe were measured. Brain penetration and target specificity of [18F]LW223 in NHPs were corroborated by PET-MR imaging under baseline and pre-blocking conditions using the validated TSPO inhibitor, (R)-PK11195, at doses ranging from 5 to 10 mg/kg. Kinetic modeling was performed using one-tissue compartment model (1TCM), two-tissue compartment model (2TCM) and Logan graphical analyses, using dynamic PET data acquisition, arterial blood collection and metabolic stability testing. Clinical PET scans were performed in two healthy volunteers (HVs). Regional brain standard uptake value ratio (SUVr) was assessed for different time intervals. RESULTS [18F]LW223 was synthesized in non-decay corrected radiochemical yields (n.d.c. RCYs) of 33.3 ± 6.5% with molar activities ranging from 1.8 ± 0.7 Ci/µmol (n = 11). [18F]LW223 was stable in formulation for up to 4 h and LogD7.4 of 2.31 ± 0.13 (n = 6) and fu of 5.80 ± 1.42% (n = 6) were determined. [18F]LW223 exhibited good brain penetration in NHPs, with a peak SUV value of ca. 1.79 in the whole brain. Pre-treatment with (R)-PK11195 substantially accelerated the washout and attenuated the area under the time-activity curve, indicating in vivo specificity of [18F]LW223 towards TSPO. Kinetic modeling demonstrated that 2TCM was the most suitable model for [18F]LW223-based neuroimaging. Global transfer rate constants (K1) and total volumes of distribution (VT) were found to be 0.10 ± 0.01 mL/cm3/min and 2.30 ± 0.17 mL/cm3, respectively. Dynamic PET data analyses across distinct time windows revealed that the VT values were relatively stable after 60 min post-injection. In a preliminary clinical study with two healthy volunteers, [18F]LW223 exhibited good brain uptake and considerable tracer retention across all analyzed brain regions. Of note, an excellent correlation between SUVr with VT was obtained when assessing the time interval from 20 to 40 min post tracer injection (SUVr(20-40 min), R2 = 0.94, p < 0.0001), suggesting this time window may be suitable to estimate specific binding to TSPO in human brain. CONCLUSION Our findings indicate that [18F]LW223 is suitable for quantitative TSPO-targeted PET imaging in higher species. Employing state-of-the-art kinetic modeling, we found that [18F]LW223 was effective in mapping TSPO throughout the NHP brain, with best model fits obtained from 2TCM and Logan graphical analyses. Overall, our results indicate that [18F]LW223 exhibits favorable tracer performance characteristics in higher species, and this novel imaging tool may hold promise to provide effective neuroinflammation imaging in patients with neurological disease.
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Affiliation(s)
- Zhiqiang Tan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Ahmed Haider
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA 30322, USA
| | - Shaojuan Zhang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Jiahui Chen
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA 30322, USA
| | - Junjie Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Kai Liao
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Guocong Li
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Huiyi Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Chenchen Dong
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Wenqing Ran
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Ying Li
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Yuefeng Li
- Guangdong Landau Biotechnology Co. Ltd., Guangzhou 510555, China
| | - Jian Rong
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA 30322, USA
| | - Yinlong Li
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA 30322, USA
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA 30322, USA.
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
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Yasuno F, Kimura Y, Ogata A, Ikenuma H, Abe J, Minami H, Nihashi T, Yokoi K, Hattori S, Shimoda N, Watanabe A, Kasuga K, Ikeuchi T, Takeda A, Sakurai T, Ito K, Kato T. Involvement of inflammation in the medial temporal region in the development of agitation in Alzheimer's disease: an in vivo positron emission tomography study. Psychogeriatrics 2023; 23:126-135. [PMID: 36403981 PMCID: PMC10100091 DOI: 10.1111/psyg.12915] [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] [Received: 09/13/2022] [Revised: 10/20/2022] [Accepted: 11/04/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND The evaluation of 11 C-DPA-713 binding using positron emission tomography for quantifying the translocator protein can be a sensitive approach in determining the level of glial activation induced by neuroinflammation. Herein, we aimed to investigate the relationship between regional 11 C-DPA713-binding potential (BPND ) and neuropsychiatric symptoms (NPS) in amyloid-positive Alzheimer's disease (AD) patients. METHODS Fifteen AD patients were enrolled in this study. Correlations were evaluated between the 11 C-DPA713-BPND and Neuropsychiatric Inventory Questionnaire (NPI-Q) scores, including scores in its four domains: agitation, psychosis, affective, and apathy. 11 C-DPA713-BPND values were compared between groups with and without the neuropsychiatric symptoms for which a relationship was observed in the abovementioned correlation analysis. RESULTS A positive correlation was found between the severity of agitation and 11 C-DPA713-BPND in the Braak 1-3 area, including the amygdala, hippocampal and parahippocampal regions, and lingual and fusiform areas. An increase in the 11 C-DPA713-BPND was observed in AD patients with agitation. We did not find any significant effects of possible confounding factors, such as age, duration of illness, education, gender, Mini-Mental State Examination score, cerebrospinal fluid amyloid β 42/40 ratio, and apolipoprotein E4 positivity, on either the 11 C-DPA713-BPND or agitation score. CONCLUSIONS Neuroinflammation in the medial temporal region and its neighbouring area was shown to be associated with the development of agitation symptoms in AD patients. Our findings extend those of previous studies showing an association between some NPS and inflammation, suggesting that immunologically based interventions for agitation can serve as an alternative treatment for dementia.
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Affiliation(s)
- Fumihiko Yasuno
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan.,Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Yasuyuki Kimura
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan.,Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Aya Ogata
- Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan.,Department of Pharmacy, Faculty of Pharmacy, Gifu University of Medical Science, Kani, Japan
| | - Hiroshi Ikenuma
- Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Junichiro Abe
- Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Hiroyuki Minami
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Takashi Nihashi
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Kastunori Yokoi
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Saori Hattori
- Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Nobuyoshi Shimoda
- Molecular Analysis Division, Centre for Core Facility Administration, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Atsushi Watanabe
- Equipment Management Division, Centre for Core Facility Administration, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Kensaku Kasuga
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, Japan
| | - Akinori Takeda
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Takashi Sakurai
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Kengo Ito
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan.,Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Takashi Kato
- National Hospital for Geriatric Medicine, National Centre for Geriatrics and Gerontology, Obu, Japan.,Department of Clinical and Experimental Neuroimaging, Centre for Development of Advanced Medicine for Dementia, National Centre for Geriatrics and Gerontology, Obu, Japan
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9
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Huang J. Novel brain PET imaging agents: Strategies for imaging neuroinflammation in Alzheimer’s disease and mild cognitive impairment. Front Immunol 2022; 13:1010946. [PMID: 36211392 PMCID: PMC9537554 DOI: 10.3389/fimmu.2022.1010946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/06/2022] [Indexed: 11/25/2022] Open
Abstract
Alzheimer’s disease (AD) is a devastating neurodegenerative disease with a concealed onset and continuous deterioration. Mild cognitive impairment (MCI) is the prodromal stage of AD. Molecule-based imaging with positron emission tomography (PET) is critical in tracking pathophysiological changes among AD and MCI patients. PET with novel targets is a promising approach for diagnostic imaging, particularly in AD patients. Our present review overviews the current status and applications of in vivo molecular imaging toward neuroinflammation. Although radiotracers can remarkably diagnose AD and MCI patients, a variety of limitations prevent the recommendation of a single technique. Recent studies examining neuroinflammation PET imaging suggest an alternative approach to evaluate disease progression. This review concludes that PET imaging towards neuroinflammation is considered a promising approach to deciphering the enigma of the pathophysiological process of AD and MCI.
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10
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Seo JW, Ajenjo J, Wu B, Robinson E, Raie MN, Wang J, Tumbale SK, Buccino P, Anders DA, Shen B, Habte FG, Beinat C, James ML, Reyes ST, Ravindra Kumar S, Miles TF, Lee JT, Gradinaru V, Ferrara KW. Multimodal imaging of capsid and cargo reveals differential brain targeting and liver detargeting of systemically-administered AAVs. Biomaterials 2022; 288:121701. [PMID: 35985893 PMCID: PMC9621732 DOI: 10.1016/j.biomaterials.2022.121701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 07/23/2022] [Indexed: 11/27/2022]
Abstract
The development of gene delivery vehicles with high organ specificity when administered systemically is a critical goal for gene therapy. We combine optical and positron emission tomography (PET) imaging of 1) reporter genes and 2) capsid tags to assess the temporal and spatial distribution and transduction of adeno-associated viruses (AAVs). AAV9 and two engineered AAV vectors (PHP.eB and CAP-B10) that are noteworthy for maximizing blood-brain barrier transport were compared. CAP-B10 shares a modification in the 588 loop with PHP.eB, but also has a modification in the 455 loop, added with the goal of reducing off-target transduction. PET and optical imaging revealed that the additional modifications retained brain receptor affinity. In the liver, the accumulation of AAV9 and the engineered AAV capsids was similar (∼15% of the injected dose per cc and not significantly different between capsids at 21 h). However, the engineered capsids were primarily internalized by Kupffer cells rather than hepatocytes, and liver transduction was greatly reduced. PET reporter gene imaging after engineered AAV systemic injection provided a non-invasive method to monitor AAV-mediated protein expression over time. Through comparison with capsid tagging, differences between brain localization and transduction were revealed. In summary, AAV capsids bearing imaging tags and reporter gene payloads create a unique and powerful platform to assay the pharmacokinetics, cellular specificity and protein expression kinetics of AAV vectors in vivo, a key enabler for the field of gene therapy.
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Affiliation(s)
- Jai Woong Seo
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Javier Ajenjo
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Bo Wu
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Elise Robinson
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Marina Nura Raie
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - James Wang
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Spencer K Tumbale
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Pablo Buccino
- Stanford Cyclotron & Radiochemistry Facility (CRF), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - David Alexander Anders
- Stanford Cyclotron & Radiochemistry Facility (CRF), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Bin Shen
- Stanford Cyclotron & Radiochemistry Facility (CRF), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Frezghi G Habte
- Stanford Center for Innovation in In vivo Imaging (SCi3), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Corinne Beinat
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Michelle L James
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Samantha Taylor Reyes
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Sripriya Ravindra Kumar
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Timothy F Miles
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jason T Lee
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Viviana Gradinaru
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Katherine W Ferrara
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, School of Medicine, Stanford University, Stanford, CA, USA.
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11
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van der Geest KSM, Sandovici M, Nienhuis PH, Slart RHJA, Heeringa P, Brouwer E, Jiemy WF. Novel PET Imaging of Inflammatory Targets and Cells for the Diagnosis and Monitoring of Giant Cell Arteritis and Polymyalgia Rheumatica. Front Med (Lausanne) 2022; 9:902155. [PMID: 35733858 PMCID: PMC9207253 DOI: 10.3389/fmed.2022.902155] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/13/2022] [Indexed: 12/26/2022] Open
Abstract
Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are two interrelated inflammatory diseases affecting patients above 50 years of age. Patients with GCA suffer from granulomatous inflammation of medium- to large-sized arteries. This inflammation can lead to severe ischemic complications (e.g., irreversible vision loss and stroke) and aneurysm-related complications (such as aortic dissection). On the other hand, patients suffering from PMR present with proximal stiffness and pain due to inflammation of the shoulder and pelvic girdles. PMR is observed in 40-60% of patients with GCA, while up to 21% of patients suffering from PMR are also affected by GCA. Due to the risk of ischemic complications, GCA has to be promptly treated upon clinical suspicion. The treatment of both GCA and PMR still heavily relies on glucocorticoids (GCs), although novel targeted therapies are emerging. Imaging has a central position in the diagnosis of GCA and PMR. While [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) has proven to be a valuable tool for diagnosis of GCA and PMR, it possesses major drawbacks such as unspecific uptake in cells with high glucose metabolism, high background activity in several non-target organs and a decrease of diagnostic accuracy already after a short course of GC treatment. In recent years, our understanding of the immunopathogenesis of GCA and, to some extent, PMR has advanced. In this review, we summarize the current knowledge on the cellular heterogeneity in the immunopathology of GCA/PMR and discuss how recent advances in specific tissue infiltrating leukocyte and stromal cell profiles may be exploited as a source of novel targets for imaging. Finally, we discuss prospective novel PET radiotracers that may be useful for the diagnosis and treatment monitoring in GCA and PMR.
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Affiliation(s)
- Kornelis S. M. van der Geest
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Maria Sandovici
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Pieter H. Nienhuis
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Riemer H. J. A. Slart
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Department of Biomedical Photonic Imaging Group, University of Twente, Enschede, Netherlands
| | - Peter Heeringa
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Elisabeth Brouwer
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - William F. Jiemy
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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12
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Kinetic modeling and non-invasive approach for translocator protein quantification with 11C-DPA-713. Nucl Med Biol 2022; 108-109:76-84. [DOI: 10.1016/j.nucmedbio.2022.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 02/22/2022] [Accepted: 02/28/2022] [Indexed: 11/20/2022]
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13
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McCauley KS, Wilde JH, Bufalino SM, Neumann KD. An automated radiosynthesis of [ 18F]DPA-714 on a commercially available radiosynthesizer, Elixys Flex/Chem. Appl Radiat Isot 2022; 180:110032. [PMID: 34871885 PMCID: PMC8858596 DOI: 10.1016/j.apradiso.2021.110032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/04/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
[18F]DPA-714 is a radiotracer specific to the translocator protein (TSPO) and is useful for in vivo Positron Emission Tomography imaging studies. In this report, we have developed an automated radiosynthesis of [18F]DPA-714 on a commercially-available radiosynthesis platform, which comports with USP <823> guidelines. The wide availability of the radiosynthesis module and ease of dissemination of the production sequence will facilitate preclinical and clinical research of TSPO-related pathology.
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Affiliation(s)
- Katelyenn S. McCauley
- Department of Radiology and Medical Imaging, University of
Virginia, Charlottesville, VA, USA
| | - Justin H. Wilde
- Department of Radiology and Medical Imaging, University of
Virginia, Charlottesville, VA, USA
| | - Sophia M. Bufalino
- Department of Chemistry, University of Virginia,
Charlottesville, VA, USA
| | - Kiel D. Neumann
- Department of Radiology and Medical Imaging, University of
Virginia, Charlottesville, VA, USA,Emily Couric Clinical Cancer Center, University of
Virginia, Charlottesville, VA, USA
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14
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Jia H, Xie T. Tracers progress for positron emission tomography imaging of glial-related disease. J Biomed Res 2022; 36:321-335. [PMID: 36131689 PMCID: PMC9548440 DOI: 10.7555/jbr.36.20220017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Glial cells play an essential part in the neuron system. They can not only serve as structural blocks in the human brain but also participate in many biological processes. Extensive studies have shown that astrocytes and microglia play an important role in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, as well as glioma, epilepsy, ischemic stroke, and infections. Positron emission tomography is a functional imaging technique providing molecular-level information before anatomic changes are visible and has been widely used in many above-mentioned diseases. In this review, we focus on the positron emission tomography tracers used in pathologies related to glial cells, such as glioma, Alzheimer's disease, and neuroinflammation.
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Affiliation(s)
- Haoran Jia
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Tianwu Xie
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
- Tianwu Xie, Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China. Tel: +86-21-64048363, E-mail:
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15
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Lee SH, Denora N, Laquintana V, Mangiatordi GF, Lopedota A, Lopalco A, Cutrignelli A, Franco M, Delre P, Song IH, Kim HW, Kim SB, Park HS, Kim K, Lee SY, Youn H, Lee BC, Kim SE. Radiosynthesis and characterization of [ 18F]BS224: a next-generation TSPO PET ligand insensitive to the rs6971 polymorphism. Eur J Nucl Med Mol Imaging 2021; 49:110-124. [PMID: 34783879 PMCID: PMC8712300 DOI: 10.1007/s00259-021-05617-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 11/03/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE Translocator protein 18-kDa (TSPO) positron emission tomography (PET) is a valuable tool to detect neuroinflammed areas in a broad spectrum of neurodegenerative diseases. However, the clinical application of second-generation TSPO ligands as biomarkers is limited because of the presence of human rs6971 polymorphism that affects their binding. Here, we describe the ability of a new TSPO ligand, [18F]BS224, to identify abnormal TSPO expression in neuroinflammation independent of the rs6971 polymorphism. METHODS An in vitro competitive inhibition assay of BS224 was conducted with [3H]PK 11195 using membrane proteins isolated from 293FT cells expressing TSPO-wild type (WT) or TSPO-mutant A147T (Mut), corresponding to a high-affinity binder (HAB) and low-affinity binder (LAB), respectively. Molecular docking was performed to investigate the interaction of BS224 with the binding sites of rat TSPO-WT and TSPO-Mut. We synthesized a new 18F-labeled imidazopyridine acetamide ([18F]BS224) using boronic acid pinacol ester 6 or iodotoluene tosylate precursor 7, respectively, via aromatic 18F-fluorination. Dynamic PET scanning was performed up to 90 min after the injection of [18F]BS224 to healthy mice, and PET imaging data were obtained to estimate its absorbed doses in organs. To evaluate in vivo TSPO-specific uptake of [18F]BS224, lipopolysaccharide (LPS)-induced inflammatory and ischemic stroke rat models were used. RESULTS BS224 exhibited a high affinity (Ki = 0.51 nM) and selectivity for TSPO. The ratio of IC50 values of BS224 for LAB to that for HAB indicated that the TSPO binding affinity of BS224 has low binding sensitivity to the rs6971 polymorphism and it was comparable to that of PK 11195, which is not sensitive to the polymorphism. Docking simulations showed that the binding mode of BS224 is not affected by the A147T mutation and consequently supported the observed in vitro selectivity of [18F]BS224 regardless of polymorphisms. With optimal radiochemical yield (39 ± 6.8%, decay-corrected) and purity (> 99%), [18F]BS224 provided a clear visible image of the inflammatory lesion with a high signal-to-background ratio in both animal models (BPND = 1.43 ± 0.17 and 1.57 ± 0.37 in the LPS-induced inflammatory and ischemic stroke rat models, respectively) without skull uptake. CONCLUSION Our results suggest that [18F]BS224 may be a promising TSPO ligand to gauge neuroinflammatory disease-related areas in a broad range of patients irrespective of the common rs6971 polymorphism.
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Affiliation(s)
- Sang Hee Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Nunzio Denora
- Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, 70121 Bari, Italy
| | - Valentino Laquintana
- Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, 70121 Bari, Italy
| | | | - Angela Lopedota
- Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, 70121 Bari, Italy
| | - Antonio Lopalco
- Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, 70121 Bari, Italy
| | - Annalisa Cutrignelli
- Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, 70121 Bari, Italy
| | - Massimo Franco
- Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, 70121 Bari, Italy
| | - Pietro Delre
- Institute of Crystallography, National Research Council, Via G. Amendola 122/O, 70126 Bari, Italy
- Department of Chemistry, University of Bari “A. Moro”, Via E. Orabona, 4, 70125 Bari, Italy
| | - In Ho Song
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
| | - Hye Won Kim
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Su Bin Kim
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Hyun Soo Park
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
| | - Kyungmin Kim
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, 03080 Republic of Korea
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, 03080 Republic of Korea
- Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea
| | - Seok-Yong Lee
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, 03080 Republic of Korea
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, 03080 Republic of Korea
- Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea
| | - Hyewon Youn
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, 03080 Republic of Korea
- Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea
| | - Byung Chul Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
- Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon, 16229 Republic of Korea
| | - Sang Eun Kim
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, 13620 Republic of Korea
- Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon, 16229 Republic of Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826 Republic of Korea
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16
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Siméon FG, Lee JH, Morse CL, Stukes I, Zoghbi SS, Manly LS, Liow JS, Gladding RL, Dick RM, Yan X, Taliani S, Costa B, Martini C, Da Settimo F, Castellano S, Innis RB, Pike VW. Synthesis and Screening in Mice of Fluorine-Containing PET Radioligands for TSPO: Discovery of a Promising 18F-Labeled Ligand. J Med Chem 2021; 64:16731-16745. [PMID: 34756026 PMCID: PMC8817670 DOI: 10.1021/acs.jmedchem.1c01562] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Translocator protein 18 kDa (TSPO) is a biomarker of neuroinflammation. [11C]ER176 robustly quantifies TSPO in the human brain with positron emission tomography (PET), irrespective of subject genotype. We aimed to develop an ER176 analog with potential for labeling with longer-lived fluorine-18 (t1/2 = 109.8 min). New fluoro and trifluoromethyl analogs of ER176 were prepared through a concise synthetic strategy. These ligands showed high TSPO affinity and low human genotype sensitivity. Each ligand was initially labeled by a generic 11C-methylation procedure, thereby enabling speedy screening in mice. Each radioligand was rapidly taken up and well retained in the mouse brain at baseline after intravenous injection. Preblocking of TSPO showed that high proportions of brain uptake were specifically bound to TSPO at baseline. Overall, the 3-fluoro analog of [11C]ER176 ([11C]3b) displayed the most promising imaging properties. Therefore, a method was developed to label 3b with [18F]fluoride ion. [18F]3b gave similarly promising PET imaging results and deserves evaluation in higher species.
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Affiliation(s)
- Fabrice G Siméon
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jae-Hoon Lee
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 03772, South Korea
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ian Stukes
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Lester S Manly
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Rachel M Dick
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Xuefeng Yan
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | | | - Sabrina Castellano
- Department of Pharmacy, University of Salerno, 84084 Fisciano, SA, Italy
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
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17
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Sander CY, Bovo S, Torrado-Carvajal A, Albrecht D, Deng H, Napadow V, Price JC, Hooker JM, Loggia ML. [ 11C]PBR28 radiotracer kinetics are not driven by alterations in cerebral blood flow. J Cereb Blood Flow Metab 2021; 41:3069-3084. [PMID: 34159823 PMCID: PMC8756484 DOI: 10.1177/0271678x211023387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The positron emission tomography (PET) radiotracer [11C]PBR28 has been increasingly used to image the translocator protein (TSPO) as a marker of neuroinflammation in a variety of brain disorders. Interrelatedly, similar clinical populations can also exhibit altered brain perfusion, as has been shown using arterial spin labelling in magnetic resonance imaging (MRI) studies. Hence, an unsolved debate has revolved around whether changes in perfusion could alter delivery, uptake, or washout of the radiotracer [11C]PBR28, and thereby influence outcome measures that affect interpretation of TSPO upregulation. In this simultaneous PET/MRI study, we demonstrate that [11C]PBR28 signal elevations in chronic low back pain patients are not accompanied, in the same regions, by increases in cerebral blood flow (CBF) compared to healthy controls, and that areas of marginal hypoperfusion are not accompanied by decreases in [11C]PBR28 signal. In non-human primates, we show that hypercapnia-induced increases in CBF during radiotracer delivery or washout do not alter [11C]PBR28 outcome measures. The combined results from two methodologically distinct experiments provide support from human data and direct experimental evidence from non-human primates that changes in CBF do not influence outcome measures reported by [11C]PBR28 PET imaging studies and corresponding interpretations of the biological meaning of TSPO upregulation.
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Affiliation(s)
- Christin Y Sander
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Stefano Bovo
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Information Engineering, University of Padova, Padova, Italy
| | - Angel Torrado-Carvajal
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Medical Image Analysis and Biometry Laboratory, Universidad Rey Juan Carlos, Madrid, Spain
| | - Daniel Albrecht
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Hongping Deng
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Vitaly Napadow
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Julie C Price
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Jacob M Hooker
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Marco L Loggia
- Department of Radiology, Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
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18
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Ranson JM, Rittman T, Hayat S, Brayne C, Jessen F, Blennow K, van Duijn C, Barkhof F, Tang E, Mummery CJ, Stephan BCM, Altomare D, Frisoni GB, Ribaldi F, Molinuevo JL, Scheltens P, Llewellyn DJ. Modifiable risk factors for dementia and dementia risk profiling. A user manual for Brain Health Services-part 2 of 6. Alzheimers Res Ther 2021; 13:169. [PMID: 34635138 PMCID: PMC8507172 DOI: 10.1186/s13195-021-00895-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 08/26/2021] [Indexed: 12/14/2022]
Abstract
We envisage the development of new Brain Health Services to achieve primary and secondary dementia prevention. These services will complement existing memory clinics by targeting cognitively unimpaired individuals, where the focus is on risk profiling and personalized risk reduction interventions rather than diagnosing and treating late-stage disease. In this article, we review key potentially modifiable risk factors and genetic risk factors and discuss assessment of risk factors as well as additional fluid and imaging biomarkers that may enhance risk profiling. We then outline multidomain measures and risk profiling and provide practical guidelines for Brain Health Services, with consideration of outstanding uncertainties and challenges. Users of Brain Health Services should undergo risk profiling tailored to their age, level of risk, and availability of local resources. Initial risk assessment should incorporate a multidomain risk profiling measure. For users aged 39-64, we recommend the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) Dementia Risk Score, whereas for users aged 65 and older, we recommend the Brief Dementia Screening Indicator (BDSI) and the Australian National University Alzheimer's Disease Risk Index (ANU-ADRI). The initial assessment should also include potentially modifiable risk factors including sociodemographic, lifestyle, and health factors. If resources allow, apolipoprotein E ɛ4 status testing and structural magnetic resonance imaging should be conducted. If this initial assessment indicates a low dementia risk, then low intensity interventions can be implemented. If the user has a high dementia risk, additional investigations should be considered if local resources allow. Common variant polygenic risk of late-onset AD can be tested in middle-aged or older adults. Rare variants should only be investigated in users with a family history of early-onset dementia in a first degree relative. Advanced imaging with 18-fluorodeoxyglucose positron emission tomography (FDG-PET) or amyloid PET may be informative in high risk users to clarify the nature and burden of their underlying pathologies. Cerebrospinal fluid biomarkers are not recommended for this setting, and blood-based biomarkers need further validation before clinical use. As new technologies become available, advances in artificial intelligence are likely to improve our ability to combine diverse data to further enhance risk profiling. Ultimately, Brain Health Services have the potential to reduce the future burden of dementia through risk profiling, risk communication, personalized risk reduction, and cognitive enhancement interventions.
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Affiliation(s)
- Janice M Ranson
- College of Medicine and Health, University of Exeter, Exeter, UK
- Deep Dementia Phenotyping (DEMON) Network, Exeter, UK
| | - Timothy Rittman
- Deep Dementia Phenotyping (DEMON) Network, Exeter, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Shabina Hayat
- Department of Public Health and Primary Care, Cambridge Public Health, University of Cambridge, Cambridge, UK
| | - Carol Brayne
- Department of Public Health and Primary Care, Cambridge Public Health, University of Cambridge, Cambridge, UK
| | - Frank Jessen
- Department of Psychiatry and Psychotherapy, Medical Faculty, University of Cologne, Cologne, Germany
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Cornelia van Duijn
- Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Frederik Barkhof
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, UK
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Eugene Tang
- Deep Dementia Phenotyping (DEMON) Network, Exeter, UK
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Catherine J Mummery
- Deep Dementia Phenotyping (DEMON) Network, Exeter, UK
- Dementia Research Centre, Institute of Neurology, University College London, and National Hospital for Neurology and Neurosurgery, University College London Hospital, London, UK
| | - Blossom C M Stephan
- Institute of Mental Health, Division of Psychiatry and Applied Psychology, School of Medicine, Nottingham University, Nottingham, UK
| | - Daniele Altomare
- Laboratory of Neuroimaging of Aging (LANVIE), University of Geneva, Geneva, Switzerland
- Memory Clinic, Geneva University Hospitals, Geneva, Switzerland
| | - Giovanni B Frisoni
- Laboratory of Neuroimaging of Aging (LANVIE), University of Geneva, Geneva, Switzerland
- Memory Clinic, Geneva University Hospitals, Geneva, Switzerland
| | - Federica Ribaldi
- Laboratory of Neuroimaging of Aging (LANVIE), University of Geneva, Geneva, Switzerland
- Memory Clinic, Geneva University Hospitals, Geneva, Switzerland
- Laboratory of Alzheimer's Neuroimaging and Epidemiology (LANE), Saint John of God Clinical Research Centre, Brescia, Italy
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - José Luis Molinuevo
- Barcelonaβeta Brain Research Center (BBRC), Pasqual Maragall Foundation, Barcelona, Spain
| | - Philip Scheltens
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
- Life Science Partners, Amsterdam, The Netherlands
| | - David J Llewellyn
- College of Medicine and Health, University of Exeter, Exeter, UK.
- Deep Dementia Phenotyping (DEMON) Network, Exeter, UK.
- Alan Turing Institute, London, UK.
- 2.04 College House, St Luke's Campus, University of Exeter Medical School, Exeter, EX1 2 LU, UK.
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19
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Translation of 11C-labeled tracer synthesis to a CGMP environment as exemplified by [ 11C]ER176 for PET imaging of human TSPO. Nat Protoc 2021; 16:4419-4445. [PMID: 34363068 DOI: 10.1038/s41596-021-00584-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 06/07/2021] [Indexed: 11/08/2022]
Abstract
Radiotracers labeled with carbon-11 (t1/2 = 20.4 min) are widely used with positron emission tomography for biomedical research. Radiotracers must be produced for positron emission tomography studies in humans according to prescribed time schedules while also meeting current good manufacturing practice. Translation of an experimental radiosynthesis to a current good manufacturing practice environment is challenging. Here we exemplify such translation with a protocol for the production of an emerging radiotracer for imaging brain translocator protein 18 kDa, namely [11C]ER176. This radiotracer is produced by rapid conversion of cyclotron-produced [11C]carbon dioxide into [11C]iodomethane, which is then used to treat N-desmethyl-ER176 in the presence of base (tBuOK) at room temperature for 5 min. [11C]ER176 is separated in high purity by reversed-phase HPLC and formulated for intravenous injection in sterile ethanol-saline. The radiosynthesis is reliable and takes 50 min. Quality control takes another 20 min. All aspects of the protocol, including quality control, are discussed.
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20
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Ji B, Ono M, Yamasaki T, Fujinaga M, Zhang MR, Seki C, Aoki I, Kito S, Sawada M, Suhara T, Sahara N, Higuchi M. Detection of Alzheimer's disease-related neuroinflammation by a PET ligand selective for glial versus vascular translocator protein. J Cereb Blood Flow Metab 2021; 41:2076-2089. [PMID: 33557690 PMCID: PMC8327108 DOI: 10.1177/0271678x21992457] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A substantial and constitutive expression of translocator protein (TSPO) in cerebral blood vessels hampers the sensitive detection of neuroinflammation characterized by greatly induced TSPO expression in activated glia. Here, we conducted in vivo positron emission tomography (PET) and in vitro autoradiographic imaging of normal and TSPO-deficient mouse brains to compare the binding properties of 18F-FEBMP, a relatively novel TSPO radioligand developed for human studies based on its insensitivity to a common polymorphism, with 11C-PK11195, as well as other commonly used TSPO radioligands including 11C-PBR28, 11C-Ac5216 and 18F-FEDAA1106. TSPO in cerebral vessels of normal mice was found to provide a major binding site for 11C-PK11195, 11C-PBR28 and 18F-FEDAA1106, in contrast to no overt specific binding of 18F-FEBMP and 11C-Ac5216 to this vascular component. In addition, 18F-FEBMP yielded PET images of microglial TSPO with a higher contrast than 11C-PK11195 in a tau transgenic mouse modeling Alzheimer's disease (AD) and allied neurodegenerative tauopathies. Moreover, TSPO expression examined by immunoblotting was significantly increased in AD brains compared with healthy controls, and was well correlated with the autoradiographic binding of 18F-FEBMP but not 11C-PK11195. Our findings support the potential advantage of comparatively glial TSPO-selective radioligands such as 18F-FEBMP for PET imaging of inflammatory glial cells.
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Affiliation(s)
- Bin Ji
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Maiko Ono
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tomoteru Yamasaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Masayuki Fujinaga
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Chie Seki
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Ichio Aoki
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Seiji Kito
- Research, Development and Support Center, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Makoto Sawada
- Department of Brain Function, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Tetsuya Suhara
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Naruhiko Sahara
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
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Akerele MI, Zein SA, Pandya S, Nikolopoulou A, Gauthier SA, Raj A, Henchcliffe C, Mozley PD, Karakatsanis NA, Gupta A, Babich J, Nehmeh SA. Population-based input function for TSPO quantification and kinetic modeling with [ 11C]-DPA-713. EJNMMI Phys 2021; 8:39. [PMID: 33914185 PMCID: PMC8085191 DOI: 10.1186/s40658-021-00381-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/29/2021] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Quantitative positron emission tomography (PET) studies of neurodegenerative diseases typically require the measurement of arterial input functions (AIF), an invasive and risky procedure. This study aims to assess the reproducibility of [11C]DPA-713 PET kinetic analysis using population-based input function (PBIF). The final goal is to possibly eliminate the need for AIF. MATERIALS AND METHODS Eighteen subjects including six healthy volunteers (HV) and twelve Parkinson disease (PD) subjects from two [11C]-DPA-713 PET studies were included. Each subject underwent 90 min of dynamic PET imaging. Five healthy volunteers underwent a test-retest scan within the same day to assess the repeatability of the kinetic parameters. Kinetic modeling was carried out using the Logan total volume of distribution (VT) model. For each data set, kinetic analysis was performed using a patient-specific AIF (PSAIF, ground-truth standard) and then repeated using the PBIF. PBIF was generated using the leave-one-out method for each subject from the remaining 17 subjects and after normalizing the PSAIFs by 3 techniques: (a) Weightsubject×DoseInjected, (b) area under AIF curve (AUC), and (c) Weightsubject×AUC. The variability in the VT measured with PSAIF, in the test-retest study, was determined for selected brain regions (white matter, cerebellum, thalamus, caudate, putamen, pallidum, brainstem, hippocampus, and amygdala) using the Bland-Altman analysis and for each of the 3 normalization techniques. Similarly, for all subjects, the variabilities due to the use of PBIF were assessed. RESULTS Bland-Altman analysis showed systematic bias between test and retest studies. The corresponding mean bias and 95% limits of agreement (LOA) for the studied brain regions were 30% and ± 70%. Comparing PBIF- and PSAIF-based VT estimate for all subjects and all brain regions, a significant difference between the results generated by the three normalization techniques existed for all brain structures except for the brainstem (P-value = 0.095). The mean % difference and 95% LOA is -10% and ±45% for Weightsubject×DoseInjected; +8% and ±50% for AUC; and +2% and ± 38% for Weightsubject×AUC. In all cases, normalizing by Weightsubject×AUC yielded the smallest % bias and variability (% bias = ±2%; LOA = ±38% for all brain regions). Estimating the reproducibility of PBIF-kinetics to PSAIF based on disease groups (HV/PD) and genotype (MAB/HAB), the average VT values for all regions obtained from PBIF is insignificantly higher than PSAIF (%difference = 4.53%, P-value = 0.73 for HAB; and %difference = 0.73%, P-value = 0.96 for MAB). PBIF also tends to overestimate the difference between PD and HV for HAB (% difference = 32.33% versus 13.28%) and underestimate it in MAB (%difference = 6.84% versus 20.92%). CONCLUSIONS PSAIF kinetic results are reproducible with PBIF, with variability in VT within that obtained for the test-retest studies. Therefore, VT assessed using PBIF-based kinetic modeling is clinically feasible and can be an alternative to PSAIF.
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Affiliation(s)
- Mercy I Akerele
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA.
| | - Sara A Zein
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
| | - Sneha Pandya
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
| | | | - Susan A Gauthier
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
- Department of Neurology, Weill Cornell Medical College, New York, NY, 10021, USA
- Feil Family Brain and Mind Institute, Weill Cornell Medical College, New York, NY, 10021, USA
| | - Ashish Raj
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
| | - Claire Henchcliffe
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
- Department of Neurology, Weill Cornell Medical College, New York, NY, 10021, USA
| | - P David Mozley
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
| | | | - Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
| | - John Babich
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
| | - Sadek A Nehmeh
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10021, USA
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22
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MacAskill MG, Stadulyte A, Williams L, Morgan TEF, Sloan NL, Alcaide-Corral CJ, Walton T, Wimberley C, McKenzie CA, Spath N, Mungall W, BouHaidar R, Dweck MR, Gray GA, Newby DE, Lucatelli C, Sutherland A, Pimlott SL, Tavares AAS. Quantification of Macrophage-Driven Inflammation During Myocardial Infarction with 18F-LW223, a Novel TSPO Radiotracer with Binding Independent of the rs6971 Human Polymorphism. J Nucl Med 2021; 62:536-544. [PMID: 32859708 PMCID: PMC8049364 DOI: 10.2967/jnumed.120.243600] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/28/2020] [Indexed: 01/09/2023] Open
Abstract
Myocardial infarction (MI) is one of the leading causes of death worldwide, and inflammation is central to tissue response and patient outcomes. The 18-kDa translocator protein (TSPO) has been used in PET as an inflammatory biomarker. The aims of this study were to screen novel, fluorinated, TSPO radiotracers for susceptibility to the rs6971 genetic polymorphism using in vitro competition binding assays in human brain and heart; assess whether the in vivo characteristics of our lead radiotracer, 18F-LW223, are suitable for clinical translation; and validate whether 18F-LW223 can detect macrophage-driven inflammation in a rat MI model. Methods: Fifty-one human brain and 29 human heart tissue samples were screened for the rs6971 polymorphism. Competition binding assays were conducted with 3H-PK11195 and the following ligands: PK11195, PBR28, and our novel compounds (AB5186 and LW223). Naïve rats and mice were used for in vivo PET kinetic studies, radiometabolite studies, and dosimetry experiments. Rats underwent permanent coronary artery ligation and were scanned using PET/CT with an invasive input function at 7 d after MI. For quantification of PET signal in the hypoperfused myocardium, K1 (rate constant for transfer from arterial plasma to tissues) was used as a surrogate marker of perfusion to correct the binding potential for impaired radiotracer transfer from plasma to tissue (BPTC). Results: LW223 binding to TSPO was not susceptible to the rs6971 genetic polymorphism in human brain and heart samples. In rodents, 18F-LW223 displayed a specific uptake consistent with TSPO expression, a slow metabolism in blood (69% of parent at 120 min), a high plasma free fraction of 38.5%, and a suitable dosimetry profile (effective dose of 20.5-24.5 μSv/MBq). 18F-LW223 BPTC was significantly higher in the MI cohort within the infarct territory of the anterior wall relative to the anterior wall of naïve animals (32.7 ± 5.0 vs. 10.0 ± 2.4 cm3/mL/min, P ≤ 0.001). Ex vivo immunofluorescent staining for TSPO and CD68 (macrophage marker) resulted in the same pattern seen with in vivo BPTC analysis. Conclusion:18F-LW223 is not susceptible to the rs6971 genetic polymorphism in in vitro assays, has favorable in vivo characteristics, and is able to accurately map macrophage-driven inflammation after MI.
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Affiliation(s)
- Mark G MacAskill
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
| | - Agne Stadulyte
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
| | - Lewis Williams
- School of Chemistry, WestCHEM, University of Glasgow, Glasgow, United Kingdom
| | - Timaeus E F Morgan
- School of Chemistry, WestCHEM, University of Glasgow, Glasgow, United Kingdom
| | - Nikki L Sloan
- School of Chemistry, WestCHEM, University of Glasgow, Glasgow, United Kingdom
| | - Carlos J Alcaide-Corral
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
| | - Tashfeen Walton
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
| | - Catriona Wimberley
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Chris-Anne McKenzie
- MRC Edinburgh Brain Tissue Bank, University of Edinburgh, Edinburgh, United Kingdom
| | - Nick Spath
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - William Mungall
- Bioresearch and Veterinary Services, University of Edinburgh, Edinburgh, United Kingdom
| | - Ralph BouHaidar
- Forensic Pathology, University of Edinburgh, Edinburgh, United Kingdom
| | - Marc R Dweck
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Gillian A Gray
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - David E Newby
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Andrew Sutherland
- School of Chemistry, WestCHEM, University of Glasgow, Glasgow, United Kingdom
| | - Sally L Pimlott
- School of Medicine, University of Glasgow, Glasgow, United Kingdom; and
- NHS Greater Glasgow and Clyde, Glasgow, United Kingdom
| | - Adriana A S Tavares
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
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23
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Bagnato F, Gauthier SA, Laule C, Moore GRW, Bove R, Cai Z, Cohen-Adad J, Harrison DM, Klawiter EC, Morrow SA, Öz G, Rooney WD, Smith SA, Calabresi PA, Henry RG, Oh J, Ontaneda D, Pelletier D, Reich DS, Shinohara RT, Sicotte NL. Imaging Mechanisms of Disease Progression in Multiple Sclerosis: Beyond Brain Atrophy. J Neuroimaging 2021; 30:251-266. [PMID: 32418324 DOI: 10.1111/jon.12700] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/04/2020] [Accepted: 02/18/2020] [Indexed: 12/11/2022] Open
Abstract
Clinicians involved with different aspects of the care of persons with multiple sclerosis (MS) and scientists with expertise on clinical and imaging techniques convened in Dallas, TX, USA on February 27, 2019 at a North American Imaging in Multiple Sclerosis Cooperative workshop meeting. The aim of the workshop was to discuss cardinal pathobiological mechanisms implicated in the progression of MS and novel imaging techniques, beyond brain atrophy, to unravel these pathologies. Indeed, although brain volume assessment demonstrates changes linked to disease progression, identifying the biological mechanisms leading up to that volume loss are key for understanding disease mechanisms. To this end, the workshop focused on the application of advanced magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging techniques to assess and measure disease progression in both the brain and the spinal cord. Clinical translation of quantitative MRI was recognized as of vital importance, although the need to maintain a relatively short acquisition time mandated by most radiology departments remains the major obstacle toward this effort. Regarding PET, the panel agreed upon its utility to identify ongoing pathological processes. However, due to costs, required expertise, and the use of ionizing radiation, PET was not considered to be a viable option for ongoing care of persons with MS. Collaborative efforts fostering robust study designs and imaging technique standardization across scanners and centers are needed to unravel disease mechanisms leading to progression and discovering medications halting neurodegeneration and/or promoting repair.
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Affiliation(s)
- Francesca Bagnato
- Neuroimaging Unit, Neuroimmunology Division, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Susan A Gauthier
- Judith Jaffe Multiple Sclerosis Center, Department of Neurology, Feil Family Brain and Mind Institute, and Department of Radiology, Weill Cornell Medicine, New York, NY
| | - Cornelia Laule
- Department of Radiology, Pathology, and Laboratory Medicine, Department of Physics and Astronomy, and International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - George R Wayne Moore
- Department of Pathology and Laboratory Medicine, and International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Riley Bove
- Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, CA
| | - Zhengxin Cai
- Department of Radiology and Biomedical Imaging, PET Center, Yale University, New Haven, CT
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal and Functional Neuroimaging Unit, CRIUGM, University of Montreal, Montreal, Quebec, Canada
| | - Daniel M Harrison
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD
| | - Eric C Klawiter
- Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Sarah A Morrow
- Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada
| | - Gülin Öz
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN
| | - William D Rooney
- Advanced Imaging Research Center, Departments of Biomedical Engineering, Neurology, and Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | - Seth A Smith
- Radiology and Radiological Sciences and Vanderbilt University Imaging Institute, Vanderbilt University Medical Center, and Biomedical Engineering, Vanderbilt University, Nashville, TN
| | - Peter A Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Roland G Henry
- Departments of Neurology, Radiology and Biomedical Imaging, and the UC San Francisco & Berkeley Bioengineering Graduate Group, University of California San Francisco, San Francisco, CA
| | - Jiwon Oh
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD.,Division of Neurology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Ontaneda
- Mellen Center for Multiple Sclerosis, Neurological Institute, Cleveland Clinic, Cleveland, OH
| | - Daniel Pelletier
- Department of Neurology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD
| | - Russell T Shinohara
- Department of Biostatistics, Epidemiology, and Informatics, Penn Statistics in Imaging and Visualization Center, University of Pennsylvania, Philadelphia, PA
| | - Nancy L Sicotte
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA
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- Neuroimaging Unit, Neuroimmunology Division, Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
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24
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Zhang L, Hu K, Shao T, Hou L, Zhang S, Ye W, Josephson L, Meyer JH, Zhang MR, Vasdev N, Wang J, Xu H, Wang L, Liang SH. Recent developments on PET radiotracers for TSPO and their applications in neuroimaging. Acta Pharm Sin B 2021; 11:373-393. [PMID: 33643818 PMCID: PMC7893127 DOI: 10.1016/j.apsb.2020.08.006] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022] Open
Abstract
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is predominately localized to the outer mitochondrial membrane in steroidogenic cells. Brain TSPO expression is relatively low under physiological conditions, but is upregulated in response to glial cell activation. As the primary index of neuroinflammation, TSPO is implicated in the pathogenesis and progression of numerous neuropsychiatric disorders and neurodegenerative diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), major depressive disorder (MDD) and obsessive compulsive disorder (OCD). In this context, numerous TSPO-targeted positron emission tomography (PET) tracers have been developed. Among them, several radioligands have advanced to clinical research studies. In this review, we will overview the recent development of TSPO PET tracers, focusing on the radioligand design, radioisotope labeling, pharmacokinetics, and PET imaging evaluation. Additionally, we will consider current limitations, as well as translational potential for future application of TSPO radiopharmaceuticals. This review aims to not only present the challenges in current TSPO PET imaging, but to also provide a new perspective on TSPO targeted PET tracer discovery efforts. Addressing these challenges will facilitate the translation of TSPO in clinical studies of neuroinflammation associated with central nervous system diseases.
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Key Words
- AD, Alzheimer's disease
- ALS, amyotrophic lateral sclerosis
- AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid
- ANT, adenine nucleotide transporter
- Am, molar activities
- BBB, blood‒brain barrier
- BMSC, bone marrow stromal cells
- BP, binding potential
- BPND, non-displaceable binding potential
- BcTSPO, Bacillus cereus TSPO
- CBD, corticobasal degeneration
- CNS disorders
- CNS, central nervous system
- CRAC, cholesterol recognition amino acid consensus sequence
- DLB, Lewy body dementias
- EP, epilepsy
- FTD, frontotemporal dementia
- HAB, high-affinity binding
- HD, Huntington's disease
- HSE, herpes simplex encephalitis
- IMM, inner mitochondrial membrane
- KA, kainic acid
- LAB, low-affinity binding
- LPS, lipopolysaccharide
- MAB, mixed-affinity binding
- MAO-B, monoamine oxidase B
- MCI, mild cognitive impairment
- MDD, major depressive disorder
- MMSE, mini-mental state examination
- MRI, magnetic resonance imaging
- MS, multiple sclerosis
- MSA, multiple system atrophy
- Microglial activation
- NAA/Cr, N-acetylaspartate/creatine
- Neuroinflammation
- OCD, obsessive compulsive disorder
- OMM, outer mitochondrial membrane
- P2X7R, purinergic receptor P2X7
- PAP7, RIa-associated protein
- PBR, peripheral benzodiazepine receptor
- PCA, posterior cortical atrophy
- PD, Parkinson's disease
- PDD, PD dementia
- PET, positron emission tomography
- PKA, protein kinase A
- PRAX-1, PBR-associated protein 1
- PSP, progressive supranuclear palsy
- Positron emission tomography (PET)
- PpIX, protoporphyrin IX
- QA, quinolinic acid
- RCYs, radiochemical yields
- ROS, reactive oxygen species
- RRMS, relapsing remitting multiple sclerosis
- SA, specific activity
- SAH, subarachnoid hemorrhage
- SAR, structure–activity relationship
- SCIDY, spirocyclic iodonium ylide
- SNL, selective neuronal loss
- SNR, signal to noise ratio
- SUV, standard uptake volume
- SUVR, standard uptake volume ratio
- TBAH, tetrabutyl ammonium hydroxide
- TBI, traumatic brain injury
- TLE, temporal lobe epilepsy
- TSPO
- TSPO, translocator protein
- VDAC, voltage-dependent anion channel
- VT, distribution volume
- d.c. RCYs, decay-corrected radiochemical yields
- dMCAO, distal middle cerebral artery occlusion
- fP, plasma free fraction
- n.d.c. RCYs, non-decay-corrected radiochemical yields
- p.i., post-injection
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Kagitani-Shimono K, Kato H, Kuwayama R, Tominaga K, Nabatame S, Kishima H, Hatazawa J, Taniike M. Clinical evaluation of neuroinflammation in child-onset focal epilepsy: a translocator protein PET study. J Neuroinflammation 2021; 18:8. [PMID: 33407581 PMCID: PMC7789379 DOI: 10.1186/s12974-020-02055-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/09/2020] [Indexed: 01/17/2023] Open
Abstract
Background Neuroinflammation is associated with various chronic neurological diseases, including epilepsy; however, neuroimaging approaches for visualizing neuroinflammation have not been used in the clinical routine yet. In this study, we used the translocator protein positron emission tomography (PET) with [11C] DPA713 to investigate neuroinflammation in the epileptogenic zone in patients with child-onset focal epilepsy. Methods Patients with intractable focal epilepsy were recruited at the Epilepsy Center of Osaka University; those who were taking any immunosuppressants or steroids were excluded. PET images were acquired for 60 min after intravenous administration of [11C] DPA713. The PET image of [11C] DPA713 was co-registered to individual’s magnetic resonance imaging (MRI), and the standardized uptake value ratio (SUVr) in regions of interest, which were created in non-lesions and lesions, was calculated using the cerebellum as a pseudo-reference region. In the case of epilepsy surgery, the correlation between SUVr in lesions and pathological findings was analyzed. Results Twenty-seven patients (mean age: 11.3 ± 6.2 years, male/female: 17/10) were included in this study. Of these, 85.1% showed increased uptake of [11C] DPA713 in the focal epileptic lesion. Three patients showed epileptic spasms, suggesting partial seizure onset, and all 18 patients with abnormal lesions on MRI were similarly highlighted by significant uptake of [11C] DPA713. DPA713-positive patients had a broad range of etiologies, including focal cortical dysplasia, tumors, infarction, and hippocampal sclerosis. Five out of nine MRI-negative patients showed abnormal [11C] DPA713 uptake. The SUVr of [11C] DPA713 in lesions was significantly higher than that in non-lesions. In seven patients who underwent epilepsy surgery, increased [11C] DPA713 uptake was associated with microglial activation. Conclusions This study indicates that [11C] DPA713 uptake has valuable sensitivity in the identification of epileptic foci in child-onset focal epilepsy, and inflammation is implicated in the pathophysiology in the epileptic foci caused by various etiologies. Further research is required to establish diagnostic tools for identifying focal epileptogenic zones. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-020-02055-1.
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Affiliation(s)
- Kuriko Kagitani-Shimono
- Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan. .,Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan. .,Epilepsy Center, Osaka University Hospital, Suita, Japan.
| | - Hiroki Kato
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Ryoko Kuwayama
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan.,Epilepsy Center, Osaka University Hospital, Suita, Japan
| | - Koji Tominaga
- Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.,Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan.,Epilepsy Center, Osaka University Hospital, Suita, Japan
| | - Shin Nabatame
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan.,Epilepsy Center, Osaka University Hospital, Suita, Japan
| | - Haruhiko Kishima
- Epilepsy Center, Osaka University Hospital, Suita, Japan.,Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan.,Department of Quantum Cancer Therapy Research Center for Nuclear Physics, Osaka University, Suita, Japan
| | - Masako Taniike
- Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.,Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan
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26
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Danon JJ, Tregeagle DFL, Kassiou M. Adventures in Translocation: Studies of the Translocator Protein (TSPO) 18 kDa. Aust J Chem 2021. [DOI: 10.1071/ch21176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The 18 kDa translocator protein (TSPO) is an evolutionarily conserved transmembrane protein found embedded in the outer mitochondrial membrane. A secondary target for the benzodiazepine diazepam, TSPO has been a protein of interest for researchers for decades, particularly owing to its well-established links to inflammatory conditions in the central and peripheral nervous systems. It has become a key biomarker for assessing microglial activation using positron emission tomography (PET) imaging in patients with diseases ranging from atherosclerosis to Alzheimer’s disease. This Account describes research published by our group over the past 15 years surrounding the development of TSPO ligands and their use in probing the function of this high-value target.
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Galantamine-Memantine combination in the treatment of Alzheimer's disease and beyond. Psychiatry Res 2020; 293:113409. [PMID: 32829072 DOI: 10.1016/j.psychres.2020.113409] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly population worldwide. Despite the major unmet clinical need, no new medications for the treatment of AD have been approved since 2003. Galantamine is an acetylcholinesterase inhibitor that is also a positive allosteric modulator at the α4β2 and α7nACh receptors. Memantine is an N-methyl-d-aspartate receptor modulator/agonist. Both galantamine and memantine are FDA-approved medications for the treatment of AD. The objective of this review is to highlight the potential of the galantamine-memantine combination to conduct randomized controlled trials (RCTs) in AD. Several studies have shown the combination to be effective. Neurodegenerative diseases involve multiple pathologies; therefore, combination treatment appears to be a rational approach. Although underutilized, the galantamine-memantine combination is the standard of care in the treatment of AD. Positive RCTs with the combination with concurrent improvement in symptoms and biomarkers may lead to FDA approval, which may lead to greater utilization of this combination in clinical practice.
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28
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An update into the medicinal chemistry of translocator protein (TSPO) ligands. Eur J Med Chem 2020; 209:112924. [PMID: 33081988 DOI: 10.1016/j.ejmech.2020.112924] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 01/16/2023]
Abstract
The Translocator Protein 18 kDa (TSPO) has been discovered in 1977 as an alternative binding site for the benzodiazepine diazepam. It is an evolutionary well-conserved and tryptophan-rich 169-amino acids protein with five alpha helical transmembrane domains stretching the outer mitochondrial membrane, with the carboxyl-terminus in the cytosol and a short amino-terminus in the intermembrane space of mitochondrion. At this level, together with the voltage-dependent anion channel (VDAC) and the adenine nucleotide translocase (ANT), it forms the mitochondrial permeability transition pore (MPTP). TSPO expression is ubiquitary, with higher levels in steroid producing tissues; in the central nervous system, it is mainly expressed in glial cells and in neurons. TSPO is implicated in a variety of fundamental cellular processes including steroidogenesis, heme biosynthesis, mitochondrial respiration, mitochondrial membrane potential, cell proliferation and differentiation, cell life/death balance, oxidative stress. Altered TSPO expression has been found in some pathological conditions. In particular, high TSPO expression levels have been documented in cancer, neuroinflammation, and brain injury. Conversely, low TSPO expression levels have been evidenced in anxiety disorders. Therefore, TSPO is not only an interesting drug target for therapeutic purpose (anticonvulsant, anxiolytic, etc.), but also a valid diagnostic marker of related-diseases detectable by fluorescent or radiolabeled ligands. The aim of this report is to present an update of previous reviews dealing with the medicinal chemistry of TSPO and to highlight the most outstanding advances in the development of TSPO ligands as potential therapeutic or diagnostic tools, especially referring to the last five years.
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29
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Downer OM, Marcus RE, Zürcher NR, Hooker JM. Tracing the History of the Human Translocator Protein to Recent Neurodegenerative and Psychiatric Imaging. ACS Chem Neurosci 2020; 11:2192-2200. [PMID: 32662626 DOI: 10.1021/acschemneuro.0c00362] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The human 18 kDa translocator protein (TSPO) has been widely used as a measure of glial activation in health and disease. With the continuous progress of radiotracers with increased affinity and selectivity, associations between TSPO expression, disease severity, and progression have been examined, particularly in neurodegenerative disorders such as multiple sclerosis (MS), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). However, findings in psychiatric disorders have prompted reassessment of the interpretation of regional TSPO expression differences in the brain, specifically with respect to potential neuroinflammatory components. This "mini" Review aims to guide readers through the complexity of TSPO imaging research by identifying the successes, challenges, and promising new directions of the field. We will provide a brief history of how TSPO imaging has evolved over the last three decades and present lessons learned in the context of neurodegenerative and psychiatric disorders.
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Affiliation(s)
- Olivia M. Downer
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
| | - Rachel E.G. Marcus
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
| | - Nicole R. Zürcher
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
- Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Jacob M. Hooker
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
- Harvard Medical School, Charlestown, Massachusetts 02129, United States
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30
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Rittman T. Neurological update: neuroimaging in dementia. J Neurol 2020; 267:3429-3435. [PMID: 32638104 PMCID: PMC7578138 DOI: 10.1007/s00415-020-10040-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022]
Abstract
Neuroimaging for dementia has made remarkable progress in recent years, shedding light on diagnostic subtypes of dementia, predicting prognosis and monitoring pathology. This review covers some updates in the understanding of dementia using structural imaging, positron emission tomography (PET), structural and functional connectivity, and using big data and artificial intelligence. Progress with neuroimaging methods allows neuropathology to be examined in vivo, providing a suite of biomarkers for understanding neurodegeneration and for application in clinical trials. In addition, we highlight quantitative susceptibility imaging as an exciting new technique that may prove to be a sensitive biomarker for a range of neurodegenerative diseases. There are challenges in translating novel imaging techniques to clinical practice, particularly in developing standard methodologies and overcoming regulatory issues. It is likely that clinicians will need to lead the way if these obstacles are to be overcome. Continued efforts applying neuroimaging to understand mechanisms of neurodegeneration and translating them to clinical practice will complete a revolution in neuroimaging.
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Affiliation(s)
- Timothy Rittman
- Department of Neurosciences, University of Cambridge, Cambridge, UK.
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31
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Brain PET Imaging: Value for Understanding the Pathophysiology of HIV-associated Neurocognitive Disorder (HAND). Curr HIV/AIDS Rep 2020; 16:66-75. [PMID: 30778853 DOI: 10.1007/s11904-019-00419-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize recent developments in PET imaging of neuropathologies underlying HIV-associated neurocognitive dysfunction (HAND). We concentrate on the recent post antiretroviral era (ART), highlighting clinical and preclinical brain PET imaging studies. RECENT FINDINGS In the post ART era, PET imaging has been used to better understand perturbations of glucose metabolism, neuroinflammation, the function of neurotransmitter systems, and amyloid/tau protein deposition in the brains of HIV-infected patients and HIV animal models. Preclinical and translational findings from those studies shed a new light on the complex pathophysiology underlying HAND. The molecular imaging capabilities of PET in neuro-HIV are great complements for structural imaging modalities. Recent and future PET imaging studies can improve our understanding of neuro-HIV and provide biomarkers of disease progress that could be used as surrogate endpoints in the evaluation of the effectiveness of potential neuroprotective therapies.
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32
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Shoshan-Barmatz V, Pittala S, Mizrachi D. VDAC1 and the TSPO: Expression, Interactions, and Associated Functions in Health and Disease States. Int J Mol Sci 2019; 20:ijms20133348. [PMID: 31288390 PMCID: PMC6651789 DOI: 10.3390/ijms20133348] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
The translocator protein (TSPO), located at the outer mitochondrial membrane (OMM), serves multiple functions and contributes to numerous processes, including cholesterol import, mitochondrial metabolism, apoptosis, cell proliferation, Ca2+ signaling, oxidative stress, and inflammation. TSPO forms a complex with the voltage-dependent anion channel (VDAC), a protein that mediates the flux of ions, including Ca2+, nucleotides, and metabolites across the OMM, controls metabolism and apoptosis and interacts with many proteins. This review focuses on the two OMM proteins TSPO and VDAC1, addressing their structural interaction and associated functions. TSPO appears to be involved in the generation of reactive oxygen species, proposed to represent the link between TSPO activation and VDAC, thus playing a role in apoptotic cell death. In addition, expression of the two proteins in healthy brains and diseased states is considered, as is the relationship between TSPO and VDAC1 expression. Both proteins are over-expressed in in brains from Alzheimer’s disease patients. Finally, TSPO expression levels were proposed as a biomarker of some neuropathological settings, while TSPO-interacting ligands have been considered as a potential basis for drug development.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Srinivas Pittala
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Dario Mizrachi
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
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33
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Woodcock EA, Hillmer AT, Mason GF, Cosgrove KP. Imaging Biomarkers of the Neuroimmune System among Substance Use Disorders: A Systematic Review. MOLECULAR NEUROPSYCHIATRY 2019; 5:125-146. [PMID: 31312635 PMCID: PMC6597912 DOI: 10.1159/000499621] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/13/2019] [Indexed: 12/14/2022]
Abstract
There is tremendous interest in the role of the neuroimmune system and inflammatory processes in substance use disorders (SUDs). Imaging biomarkers of the neuroimmune system in vivo provide a vital translational bridge between preclinical and clinical research. Herein, we examine two imaging techniques that measure putative indices of the neuroimmune system and review their application among SUDs. Positron emission tomography (PET) imaging of 18 kDa translocator protein availability is a marker associated with microglia. Proton magnetic resonance spectroscopy quantification of myo-inositol levels is a putative glial marker found in astrocytes. Neuroinflammatory responses are initiated and maintained by microglia and astrocytes, and thus represent important imaging markers. The goal of this review is to summarize neuroimaging findings from the substance use literature that report data using these markers and discuss possible mechanisms of action. The extant literature indicates abused substances exert diverse and complex neuroimmune effects. Moreover, drug effects may change across addiction stages, i.e. the neuroimmune effects of acute drug administration may differ from chronic use. This burgeoning field has considerable potential to improve our understanding and treatment of SUDs. Future research is needed to determine how targeting the neuroimmune system may improve treatment outcomes.
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Affiliation(s)
| | | | | | - Kelly P. Cosgrove
- Departments of Psychiatry, and of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
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34
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Best L, Ghadery C, Pavese N, Tai YF, Strafella AP. New and Old TSPO PET Radioligands for Imaging Brain Microglial Activation in Neurodegenerative Disease. Curr Neurol Neurosci Rep 2019; 19:24. [DOI: 10.1007/s11910-019-0934-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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35
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Coughlin JM, Yang T, Rebman AW, Bechtold KT, Du Y, Mathews WB, Lesniak WG, Mihm EA, Frey SM, Marshall ES, Rosenthal HB, Reekie TA, Kassiou M, Dannals RF, Soloski MJ, Aucott JN, Pomper MG. Imaging glial activation in patients with post-treatment Lyme disease symptoms: a pilot study using [ 11C]DPA-713 PET. J Neuroinflammation 2018; 15:346. [PMID: 30567544 PMCID: PMC6299943 DOI: 10.1186/s12974-018-1381-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/27/2018] [Indexed: 12/27/2022] Open
Abstract
The pathophysiology of post-treatment Lyme disease syndrome (PTLDS) may be linked to overactive immunity including aberrant activity of the brain's resident immune cells, microglia. Here we used [11C]DPA-713 and positron emission tomography to quantify the 18 kDa translocator protein, a marker of activated microglia or reactive astrocytes, in the brains of patients with post-treatment Lyme disease symptoms of any duration compared to healthy controls. Genotyping for the TSPO rs6971 polymorphism was completed, and individuals with the rare, low affinity binding genotype were excluded. Data from eight brain regions demonstrated higher [11C]DPA-713 binding in 12 patients relative to 19 controls. [11C]DPA-713 PET is a promising tool to study cerebral glial activation in PTLDS and its link to cognitive symptoms.
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Affiliation(s)
- Jennifer M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ting Yang
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alison W Rebman
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kathleen T Bechtold
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yong Du
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William B Mathews
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wojciech G Lesniak
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Erica A Mihm
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sarah M Frey
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Erica S Marshall
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hailey B Rosenthal
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tristan A Reekie
- School of Chemistry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Robert F Dannals
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark J Soloski
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - John N Aucott
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,, Lutherville, USA.
| | - Martin G Pomper
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,, Baltimore, USA.
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Foss CA, Plyku D, Ordonez AA, Sanchez-Bautista J, Rosenthal HB, Minn I, Lodge MA, Pomper MG, Sgouros G, Jain SK. Biodistribution and Radiation Dosimetry of 124I-DPA-713, a PET Radiotracer for Macrophage-Associated Inflammation. J Nucl Med 2018; 59:1751-1756. [PMID: 29700124 PMCID: PMC6225541 DOI: 10.2967/jnumed.117.207431] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/16/2018] [Indexed: 12/14/2022] Open
Abstract
Whole-body PET/CT was performed using 124I-DPA-713, a radioligand for the 18-kDa translocator protein (TSPO), to determine biodistribution and radiation dosimetry. Methods: Healthy subjects aged 18-65 y underwent whole-body PET/CT either at 4, 24, and 48 h or at 24, 48, and 72 h after intravenous injection of 124I-DPA-713. Time-activity curves were generated and used to calculate organ time-integrated activity coefficients for each subject. The resulting time-integrated activity coefficients provided input data for calculation of organ absorbed doses and effective dose for each subject using OLINDA. Subjects were genotyped for the TSPO polymorphism rs6971, and plasma protein binding of 124I-DPA-713 was measured. Results: Three male and 3 female adults with a mean age of 40 ± 19 y were imaged. The mean administered activity and mass were 70.5 ± 5.1 MBq (range, 62.4-78.1 MBq) and 469 ± 34 ng (range, 416-520 ng), respectively. There were no adverse or clinically detectable pharmacologic effects in any of the 6 subjects. No changes in vital signs, laboratory values, or electrocardiograms were observed. 124I-DPA-713 cleared rapidly (4 h after injection) from the lungs, with hepatic elimination and localization to the gastrointestinal tract. The mean effective dose over the 6 subjects was 0.459 ± 0.127 mSv/MBq, with the liver being the dose-limiting organ (0.924 ± 0.501 mGy/MBq). The percentage of free radiotracer in blood was approximately 30% at 30 and 60 min after injection. Conclusion:124I-DPA-713 clears rapidly from the lungs, with predominantly hepatic elimination, and is safe and well tolerated in healthy adults.
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Affiliation(s)
- Catherine A Foss
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Donika Plyku
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alvaro A Ordonez
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Julian Sanchez-Bautista
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hailey B Rosenthal
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Il Minn
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Martin A Lodge
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Martin G Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - George Sgouros
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sanjay K Jain
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Center for Infection and Inflammation Imaging Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Shen Z, Bao X, Wang R. Clinical PET Imaging of Microglial Activation: Implications for Microglial Therapeutics in Alzheimer's Disease. Front Aging Neurosci 2018; 10:314. [PMID: 30349474 PMCID: PMC6186779 DOI: 10.3389/fnagi.2018.00314] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
In addition to extracellular β-amyloid plaques and intracellular neurofibrillary tangles, neuroinflammation has been identified as a key pathological characteristic of Alzheimer's disease (AD). Once activated, neuroinflammatory cells called microglia acquire different activation phenotypes. At the early stage of AD, activated microglia are mainly dominated by the neuroprotective and anti-inflammatory M2 phenotype. Conversely, in the later stage of AD, the excessive activation of microglia is considered detrimental and pro-inflammatory, turning into the M1 phenotype. Therapeutic strategies targeting the modulation of microglia may regulate their specific phenotype. Fortunately, with the rapid development of in vivo imaging methodologies, visualization of microglial activation has been well-explored. In this review, we summarize the critical role of activated microglia during the pathogenesis of AD and current studies concerning imaging of microglial activation in AD patients. We explore the possibilities for identifying activated microglial phenotypes with imaging techniques and highlight promising therapies that regulate the microglial phenotype in AD mice.
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Affiliation(s)
- Zhiwei Shen
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xinjie Bao
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Renzhi Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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Simmons DA, James ML, Belichenko NP, Semaan S, Condon C, Kuan J, Shuhendler AJ, Miao Z, Chin FT, Longo FM. TSPO-PET imaging using [18F]PBR06 is a potential translatable biomarker for treatment response in Huntington's disease: preclinical evidence with the p75NTR ligand LM11A-31. Hum Mol Genet 2018; 27:2893-2912. [PMID: 29860333 PMCID: PMC6077813 DOI: 10.1093/hmg/ddy202] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/04/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder that has no cure. HD therapeutic development would benefit from a non-invasive translatable biomarker to track disease progression and treatment response. A potential biomarker is using positron emission tomography (PET) imaging with a translocator protein 18 kDa (TSPO) radiotracer to detect microglial activation, a key contributor to HD pathogenesis. The ability of TSPO-PET to identify microglial activation in HD mouse models, essential for a translatable biomarker, or therapeutic efficacy in HD patients or mice is unknown. Thus, this study assessed the feasibility of utilizing PET imaging with the TSPO tracer, [18F]PBR06, to detect activated microglia in two HD mouse models and to monitor response to treatment with LM11A-31, a p75NTR ligand known to reduce neuroinflammation in HD mice. [18F]PBR06-PET detected microglial activation in striatum, cortex and hippocampus of vehicle-treated R6/2 mice at a late disease stage and, notably, also in early and mid-stage symptomatic BACHD mice. After oral administration of LM11A-31 to R6/2 and BACHD mice, [18F]PBR06-PET discerned the reductive effects of LM11A-31 on neuroinflammation in both HD mouse models. [18F]PBR06-PET signal had a spatial distribution similar to ex vivo brain autoradiography and correlated with microglial activation markers: increased IBA-1 and TSPO immunostaining/blotting and striatal levels of cytokines IL-6 and TNFα. These results suggest that [18F]PBR06-PET is a useful surrogate marker of therapeutic efficacy in HD mice with high potential as a translatable biomarker for preclinical and clinical HD trials.
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Affiliation(s)
- Danielle A Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle L James
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Nadia P Belichenko
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Sarah Semaan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Christina Condon
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Jason Kuan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Adam J Shuhendler
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Zheng Miao
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Frederick T Chin
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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Rubin LH, Sacktor N, Creighton J, Du Y, Endres CJ, Pomper MG, Coughlin JM. Microglial activation is inversely associated with cognition in individuals living with HIV on effective antiretroviral therapy. AIDS 2018; 32:1661-1667. [PMID: 29746297 DOI: 10.1097/qad.0000000000001858] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Despite viral suppression, HIV-associated cognitive impairment persists and may be partially due to persistent immune signalling by cells of the myeloid-lineage. Here, we aimed to understand the contribution of activated microglia located in vulnerable brain regions (e.g. frontal, subcortical) of HIV-infected, virally suppressed (HIV+VS) individuals in relation to cognitive and motor function. DESIGN Twenty-one HIV+VS individuals underwent PET with [11C]DPA-713 to image the translocator protein 18 kDa (TSPO), a marker of microglial activation, and completed a comprehensive neuropsychological test battery. METHODS Multivariable linear regressions were used to examine the contribution of [11C]DPA-713 binding to cognitive performance. RESULTS Higher [11C]DPA-713 binding was associated with lower cognition among HIV+VS individuals. [11C]DPA-713 binding in middle frontal gyrus/frontal cortex, hippocampus/temporal cortex and occipital cortex was inversely associated with performance on a number of cognitive domains, including verbal memory, processing speed/attention/concentration, executive function, working memory and motor function. [C]DPA-713 binding in parietal cortex, cerebellum and thalamus was associated with only specific cognitive domains including visual construction and verbal memory. Binding was not associated with global cognitive performance. CONCLUSION The findings add to the growing body of evidence that immune-mediated brain injury may contribute to domain specific, HIV-associated, cognitive vulnerabilities despite viral suppression.
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Fukudome D, Hayes LN, Faust TE, Foss CA, Kondo MA, Lee BJ, Saito A, Kano SI, Coughlin JM, Kamiya A, Pomper MG, Sawa A, Niwa M. Translocator protein (TSPO) and stress cascades in mouse models of psychosis with inflammatory disturbances. Schizophr Res 2018; 197:492-497. [PMID: 29398205 PMCID: PMC6470041 DOI: 10.1016/j.schres.2018.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 12/12/2017] [Accepted: 01/17/2018] [Indexed: 11/28/2022]
Abstract
Changes in inflammatory cascades have been implicated in the underlying pathophysiology of psychosis. Translocator protein 18 kDa (TSPO) has been used to assess neuroinflammatory processes in psychotic disorders. Nonetheless, it is unclear whether TSPO, a mitochondrial protein, can be interpreted as a general marker for inflammation in diseases involving psychosis. To address this question, we investigated TSPO signaling in representative mouse models for psychosis with inflammatory disturbances. The maternal immune activation and cuprizone short-term exposure models show different TSPO signaling. Furthermore, we observed similarities and differences in their respective stress pathways including stress hormone signaling and oxidative stress that are functionally interconnected with the inflammatory responses. We propose that more careful studies of TSPO distribution in neuroinflammation and other stress cascades associated with psychotic symptoms will allow us to understand the biological mechanisms underlying psychosis-related behaviors.
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Affiliation(s)
- Daisuke Fukudome
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Lindsay N. Hayes
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Travis E. Faust
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Catherine A. Foss
- Russell H Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, 1550 Orleans Street, Baltimore, MD 21231, USA
| | - Mari A. Kondo
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Brian J. Lee
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Atsushi Saito
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Shin-ichi Kano
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Jennifer M. Coughlin
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Atsushi Kamiya
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | - Martin G. Pomper
- Russell H Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, 1550 Orleans Street, Baltimore, MD 21231, USA
| | - Akira Sawa
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
| | - Minae Niwa
- Department of Psychiatry, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
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41
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Edison P, Brooks DJ. Role of Neuroinflammation in the Trajectory of Alzheimer’s Disease and in vivo Quantification Using PET. J Alzheimers Dis 2018; 64:S339-S351. [DOI: 10.3233/jad-179929] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Paul Edison
- Neurology Imaging Unit, Department of Medicine, Imperial College London, London, UK
| | - David J. Brooks
- Department of Nuclear Medicine, Aarhus University, Denmark
- Institute of Neuroscience, University of Newcastle upon Tyne, UK
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Yang B, Ying L, Tang J. Artificial Neural Network Enhanced Bayesian PET Image Reconstruction. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:1297-1309. [PMID: 29870360 PMCID: PMC6132251 DOI: 10.1109/tmi.2018.2803681] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In positron emission tomography (PET) image reconstruction, the Bayesian framework with various regularization terms has been implemented to constrain the radio tracer distribution. Varying the regularizing weight of a maximum a posteriori (MAP) algorithm specifies a lower bound of the tradeoff between variance and spatial resolution measured from the reconstructed images. The purpose of this paper is to build a patch-based image enhancement scheme to reduce the size of the unachievable region below the bound and thus to quantitatively improve the Bayesian PET imaging. We cast the proposed enhancement as a regression problem which models a highly nonlinear and spatial-varying mapping between the reconstructed image patches and an enhanced image patch. An artificial neural network model named multilayer perceptron (MLP) with backpropagation was used to solve this regression problem through learning from examples. Using the BrainWeb phantoms, we simulated brain PET data at different count levels of different subjects with and without lesions. The MLP was trained using the image patches reconstructed with a MAP algorithm of different regularization parameters for one normal subject at a certain count level. To evaluate the performance of the trained MLP, reconstructed images from other simulations and two patient brain PET imaging data sets were processed. In every testing cases, we demonstrate that the MLP enhancement technique improves the noise and bias tradeoff compared with the MAP reconstruction using different regularizing weights thus decreasing the size of the unachievable region defined by the MAP algorithm in the variance/resolution plane.
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Affiliation(s)
- Bao Yang
- Department of Electrical and Computer Engineering, Oakland University, Rochester, MI, USA
| | - Leslie Ying
- Departments of Biomedical Engineering and Electrical Engineering, The State University of New York at Buffalo, Buffalo, NY, USA
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Kobayashi M, Jiang T, Telu S, Zoghbi SS, Gunn RN, Rabiner EA, Owen DR, Guo Q, Pike VW, Innis RB, Fujita M. 11C-DPA-713 has much greater specific binding to translocator protein 18 kDa (TSPO) in human brain than 11C-( R)-PK11195. J Cereb Blood Flow Metab 2018; 38:393-403. [PMID: 28322082 PMCID: PMC5851139 DOI: 10.1177/0271678x17699223] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Positron emission tomography (PET) radioligands for translocator protein 18 kDa (TSPO) are widely used to measure neuroinflammation, but controversy exists whether second-generation radioligands are superior to the prototypical agent 11C-( R)-PK11195 in human imaging. This study sought to quantitatively measure the "signal to background" ratio (assessed as binding potential ( BPND)) of 11C-( R)-PK11195 compared to one of the most promising second-generation radioligands, 11C-DPA-713. Healthy subjects had dynamic PET scans and arterial blood measurements of radioligand after injection of either 11C-( R)-PK11195 (16 subjects) or 11C-DPA-713 (22 subjects). To measure the amount of specific binding, a subset of these subjects was scanned after administration of the TSPO blocking drug XBD173 (30-90 mg PO). 11C-DPA-713 showed a significant sensitivity to genotype in brain, whereas 11C-( R)-PK11195 did not. Lassen occupancy plot analysis revealed that the specific binding of 11C-DPA-713 was much greater than that of 11C-( R)-PK11195. The BPND in high-affinity binders was about 10-fold higher for 11C-DPA-713 (7.3) than for 11C-( R)-PK11195 (0.75). Although the high specific binding of 11C-DPA-713 suggests it is an ideal ligand to measure TSPO, we also found that its distribution volume increased over time, consistent with the accumulation of radiometabolites in brain.
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Affiliation(s)
- Masato Kobayashi
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
| | - Teresa Jiang
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
| | - Sanjay Telu
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
| | - Sami S Zoghbi
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
| | - Roger N Gunn
- 2 Imanova Ltd, London, UK.,3 Division of Brain Sciences, Department of Medicine, Imperial College, London, UK
| | | | - David R Owen
- 3 Division of Brain Sciences, Department of Medicine, Imperial College, London, UK
| | - Qi Guo
- 2 Imanova Ltd, London, UK
| | - Victor W Pike
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
| | - Robert B Innis
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
| | - Masahiro Fujita
- 1 Molecular Imaging Branch, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA
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44
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Bonsack F, Foss CA, Arbab AS, Alleyne CH, Pomper MG, Sukumari-Ramesh S. [ 125 I]IodoDPA-713 Binding to 18 kDa Translocator Protein (TSPO) in a Mouse Model of Intracerebral Hemorrhage: Implications for Neuroimaging. Front Neurosci 2018. [PMID: 29520214 PMCID: PMC5826955 DOI: 10.3389/fnins.2018.00066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Intracerebral hemorrhage (ICH) is a fatal stroke subtype with significant public health impact. Although neuroinflammation is a leading cause of neurological deficits after ICH, no imaging tool is currently available to monitor brain inflammation in ICH patients. Given the role of TSPO in neuroinflammation, herein we investigate whether a second-generation TSPO ligand, [125 I]IodoDPA-713 can be used to monitor the changes in TSPO expression in a preclinical model of intracerebral hemorrhage. Male CD1 mice were subjected to ICH/Sham. The brain sections, collected at different time points were incubated with [125 I]IodoDPA-713 and the brain uptake of [125 I]IodoDPA-713 was estimated using autoradiography. The specificity of [125 I]IodoDPA-713 binding was confirmed by a competitive displacement study with an unlabeled TSPO ligand, PK11195. [125 I]IodoDPA-713 binding was higher in the ipsilateral striatum with an enhanced binding observed in the peri-hematomal brain region after ICH, whereas the brain sections from sham as well as contralateral brain areas of ICH exhibited marginal binding of [125 I]IodoDPA-713. PK11195 completely reversed the [125 I] IodoDPA-713 binding to brain sections suggesting a specific TSPO-dependent binding of [125 I]IodoDPA-713 after ICH. This was further confirmed with immunohistochemistry analysis of adjacent sections, which revealed a remarkable expression of TSPO in the areas of high [125 I]IodoDPA-713 binding after ICH. The specific as well as enhanced binding of [125 I]IodoDPA-713 to the ipsilateral brain areas after ICH as assessed by autoradiography analysis provides a strong rationale for testing the applicability of [125 I]IodoDPA-713 for non-invasive neuroimaging in preclinical models of ICH.
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Affiliation(s)
- Frederick Bonsack
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Catherine A Foss
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Ali S Arbab
- Laboratory of Tumor Angiogenesis, Georgia Cancer Center, Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA, United States
| | - Cargill H Alleyne
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Martin G Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Sangeetha Sukumari-Ramesh
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States
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45
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Notter T, Coughlin JM, Gschwind T, Weber-Stadlbauer U, Wang Y, Kassiou M, Vernon AC, Benke D, Pomper MG, Sawa A, Meyer U. Translational evaluation of translocator protein as a marker of neuroinflammation in schizophrenia. Mol Psychiatry 2018; 23:323-334. [PMID: 28093569 DOI: 10.1038/mp.2016.248] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/14/2016] [Accepted: 11/28/2016] [Indexed: 02/08/2023]
Abstract
Positron emission tomography (PET) imaging with radiotracers that target translocator protein 18 kDa (TSPO) has become a popular approach to assess putative neuroinflammatory processes and associated microglia activation in psychotic illnesses. It remains unclear, however, whether TSPO imaging can accurately capture low-grade inflammatory processes such as those present in schizophrenia and related disorders. Therefore, we evaluated the validity of TSPO as a disease-relevant marker of inflammation using a translational approach, which combined neurodevelopmental and neurodegenerative mouse models with PET imaging in patients with recent-onset schizophrenia and matched controls. Using an infection-mediated neurodevelopmental mouse model, we show that schizophrenia-relevant behavioral abnormalities and increased inflammatory cytokine expression are associated with reduced prefrontal TSPO levels. On the other hand, TSPO was markedly upregulated in a mouse model of acute neurodegeneration and reactive gliosis, which was induced by intrahippocampal injection of kainic acid. In both models, the changes in TSPO levels were not restricted to microglia but emerged in various cell types, including microglia, astrocytes and vascular endothelial cells. Human PET imaging using the second-generation TSPO radiotracer [11C]DPA-713 revealed a strong trend towards reduced TSPO binding in the middle frontal gyrus of patients with recent-onset schizophrenia, who were previously shown to display increased levels of inflammatory cytokines in peripheral and central tissues. Together, our findings challenge the common assumption that central low-grade inflammation in schizophrenia is mirrored by increased TSPO expression or ligand binding. Our study further underscores the need to interpret altered TSPO binding in schizophrenia with caution, especially when measures of TSPO are not complemented with other markers of inflammation. Unless more selective microglial markers are available for PET imaging, quantification of cytokines and other inflammatory biomarkers, along with their molecular signaling pathways, may be more accurate in attempts to characterize inflammatory profiles in schizophrenia and other mental disorders that lack robust reactive gliosis.
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Affiliation(s)
- T Notter
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - J M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - T Gschwind
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - U Weber-Stadlbauer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
| | - Y Wang
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - M Kassiou
- School of Chemistry, The University of Sydney, Sydney, NSW, Australia
- Discipline of Medical Radiation Sciences, The University of Sydney, Sydney, NSW, Australia
| | - A C Vernon
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- King's College London, Institute of Psychiatry Psychology and Neuroscience, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - D Benke
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - M G Pomper
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - A Sawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - U Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
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Cumming P, Burgher B, Patkar O, Breakspear M, Vasdev N, Thomas P, Liu GJ, Banati R. Sifting through the surfeit of neuroinflammation tracers. J Cereb Blood Flow Metab 2018; 38:204-224. [PMID: 29256293 PMCID: PMC5951023 DOI: 10.1177/0271678x17748786] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/26/2017] [Accepted: 11/09/2017] [Indexed: 01/09/2023]
Abstract
The first phase of molecular brain imaging of microglial activation in neuroinflammatory conditions began some 20 years ago with the introduction of [11C]-( R)-PK11195, the prototype isoquinoline ligand for translocator protein (18 kDa) (TSPO). Investigations by positron emission tomography (PET) revealed microgliosis in numerous brain diseases, despite the rather low specific binding signal imparted by [11C]-( R)-PK11195. There has since been enormous expansion of the repertoire of TSPO tracers, many with higher specific binding, albeit complicated by allelic dependence of the affinity. However, the specificity of TSPO PET for revealing microglial activation not been fully established, and it has been difficult to judge the relative merits of the competing tracers and analysis methods with respect to their sensitivity for detecting microglial activation. We therefore present a systematic comparison of 13 TSPO PET and single photon computed tomography (SPECT) tracers belonging to five structural classes, each of which has been investigated by compartmental analysis in healthy human brain relative to a metabolite-corrected arterial input. We emphasize the need to establish the non-displaceable binding component for each ligand and conclude with five recommendations for a standard approach to define the cellular distribution of TSPO signals, and to characterize the properties of candidate TSPO tracers.
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Affiliation(s)
- Paul Cumming
- School of Psychology and Counselling and IHBI, Faculty of Health, Queensland University of Technology, Brisbane, Australia
- QIMR Berghofer Institute, Brisbane, Australia
| | - Bjorn Burgher
- QIMR Berghofer Institute, Brisbane, Australia
- Metro North Mental Health Service, Brisbane, Australia
| | - Omkar Patkar
- School of Psychology and Counselling and IHBI, Faculty of Health, Queensland University of Technology, Brisbane, Australia
- QIMR Berghofer Institute, Brisbane, Australia
| | - Michael Breakspear
- QIMR Berghofer Institute, Brisbane, Australia
- Metro North Mental Health Service, Brisbane, Australia
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Paul Thomas
- Herston Imaging Research Facility, Faculty of Medicine, University of Queensland Centre for Clinical Research, Herston, Australia
| | - Guo-Jun Liu
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
- National Imaging Facility, Brain and Mind Centre and Faculty of Health Sciences, University of Sydney, Camperdown, Australia
| | - Richard Banati
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
- National Imaging Facility, Brain and Mind Centre and Faculty of Health Sciences, University of Sydney, Camperdown, Australia
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47
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Knezevic D, Mizrahi R. Molecular imaging of neuroinflammation in Alzheimer's disease and mild cognitive impairment. Prog Neuropsychopharmacol Biol Psychiatry 2018; 80:123-131. [PMID: 28533150 DOI: 10.1016/j.pnpbp.2017.05.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 02/28/2017] [Accepted: 05/09/2017] [Indexed: 11/26/2022]
Abstract
Neuroinflammatory changes have been demonstrated to be an important feature of Alzheimer's disease (AD); however, the exact role of neuroinflammation and its progression during disease is still not well understood. One of the main drivers of the neuroinflammatory process are microglial cells. Positron Emission Tomography allows for the quantification of microglial activation by labelling the Translocator Protein 18kDa (TSPO), which becomes overexpressed upon activation of microglial cells. Several radioligands have been designed to target TSPO and have been studied in-vivo in AD populations. While most studies have shown important increases in TSPO binding in AD populations compared to healthy volunteers, whether the neuroinflammatory progress occurs early on or later during disease is still unclear. In order to investigate the early changes in neuroinflammation, studies have sought to investigate microglial activation in patients with mild cognitive impairment (MCI), which is defined as a transitional stage between normal aging and dementia. In this prodromal population, conflicting results have been reported with some studies reporting increased binding in MCI, while others demonstrate no differences from controls. Here we review the TSPO PET studies in AD and MCI populations and discuss the important methodological considerations of imaging microglial activation.
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Affiliation(s)
- Dunja Knezevic
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Romina Mizrahi
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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48
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Notter T, Coughlin JM, Sawa A, Meyer U. Reconceptualization of translocator protein as a biomarker of neuroinflammation in psychiatry. Mol Psychiatry 2018; 23:36-47. [PMID: 29203847 DOI: 10.1038/mp.2017.232] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/05/2017] [Accepted: 10/02/2017] [Indexed: 02/06/2023]
Abstract
A great deal of interest in psychiatric research is currently centered upon the pathogenic role of inflammatory processes. Positron emission tomography (PET) using radiolabeled ligands selective for the 18 kDa translocator protein (TSPO) has become the most widely used technique to assess putative neuroimmune abnormalities in vivo. Originally used to detect discrete neurotoxic damages, TSPO has generally turned into a biomarker of 'neuroinflammation' or 'microglial activation'. Psychiatric research has mostly accepted these denotations of TSPO, even if they may be inadequate and misleading under many pathological conditions. A reliable and neurobiologically meaningful diagnosis of 'neuroinflammation' or 'microglial activation' is unlikely to be achieved by the sole use of TSPO PET imaging. It is also very likely that the pathological meanings of altered TSPO binding or expression are disease-specific, and therefore, not easily generalizable across different neuropathologies or inflammatory conditions. This difficulty is intricately linked to the varying (and still ill-defined) physiological functions and cellular expression patterns of TSPO in health and disease. While altered TSPO binding or expression may indeed mirror ongoing neuroinflammatory processes in some cases, it may reflect other pathophysiological processes such as abnormalities in cell metabolism, energy production and oxidative stress in others. Hence, the increasing popularity of TSPO PET imaging has paradoxically introduced substantial uncertainty regarding the nature and meaning of neuroinflammatory processes and microglial activation in psychiatry, and likely in other neuropathological conditions as well. The ambiguity of conceiving TSPO simply as a biomarker of 'neuroinflammation' or 'microglial activation' calls for alternative interpretations and complimentary approaches. Without the latter, the ongoing scientific efforts and excitement surrounding the role of the neuroimmune system in psychiatry may not turn into therapeutic hope for affected individuals.
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Affiliation(s)
- T Notter
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - J M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - A Sawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - U Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
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Barichello T, Simões LR, Collodel A, Giridharan VV, Dal-Pizzol F, Macedo D, Quevedo J. The translocator protein (18 kDa) and its role in neuropsychiatric disorders. Neurosci Biobehav Rev 2017; 83:183-199. [DOI: 10.1016/j.neubiorev.2017.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/20/2017] [Accepted: 10/10/2017] [Indexed: 02/08/2023]
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Sakata M, Ishibashi K, Imai M, Wagatsuma K, Ishii K, Hatano K, Ishiwata K, Toyohara J. Assessment of safety, efficacy, and dosimetry of a novel 18-kDa translocator protein ligand, [ 11C]CB184, in healthy human volunteers. EJNMMI Res 2017; 7:26. [PMID: 28337723 PMCID: PMC5364125 DOI: 10.1186/s13550-017-0271-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/01/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND N,N-di-n-propyl-2-[2-(4-[11C]methoxyphenyl)-6,8-dichloroimidazol[1,2-a]pyridine-3-yl]acetamide ([11C]CB184) is a novel selective radioligand for the 18-kD translocator protein (TSPO), which is upregulated in activated microglia in the brain, and may be useful in positron emission tomography (PET). We examined the safety, radiation dosimetry, and initial brain imaging with [11C]CB184 in healthy human volunteers. RESULTS Dynamic [11C]CB184 PET scans (90 min) were performed in five healthy male subjects. During the scan, arterial blood was sampled at various time intervals, and the fraction of the parent compound in plasma was determined with high-performance liquid chromatography. No serious adverse events occurred in any of the subjects throughout the study period. [11C]CB184 was metabolized in the periphery: 36.7% ± 5.7% of the radioactivity in plasma was detected as the unchanged form after 60 min. The total distribution volume (V T) was estimated with a two-tissue compartment model. The V T of [11C]CB184 was highest in the thalamus (5.1 ± 0.4), followed by the cerebellar cortex (4.4 ± 0.2), and others. Although regional differences were small, the observed [11C]CB184 binding pattern was consistent with the TSPO distribution in the normal human brain. Radiation dosimetry was determined in three healthy male subjects using a serial whole-body PET scan acquired over 2 h after [11C]CB184 injection. [11C]CB184 PET demonstrated high uptake in the gallbladder at a later time (>60 min). In urine obtained approximately 100 min post-injection, 0.3% of the total injected radioactivity was recovered, indicating hepatobiliary excretion of radioactivity. The absorbed dose (μGy/MBq) was highest in the kidneys (21.0 ± 0.5) followed by the lungs (16.8 ± 2.7), spleen (16.6 ± 6.6), and pancreas (16.5 ± 2.2). The estimated effective dose for [11C]CB184 was 5.9 ± 0.6 μSv/MBq. CONCLUSIONS This initial evaluation indicated that [11C]CB184 is feasible for imaging of TSPO in the brain.
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Affiliation(s)
- Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, 173-0015 Tokyo, Japan
| | - Kenji Ishibashi
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, 173-0015 Tokyo, Japan
| | - Masamichi Imai
- Department of Radiology, Toranomon Hospital, Tokyo, Japan
| | - Kei Wagatsuma
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, 173-0015 Tokyo, Japan
| | - Kenji Ishii
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, 173-0015 Tokyo, Japan
| | - Kentaro Hatano
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kiichi Ishiwata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, 173-0015 Tokyo, 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
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, 173-0015 Tokyo, Japan
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