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Emvalomenos GM, Kang JWM, Jupp B, Mychasiuk R, Keay KA, Henderson LA. Recent developments and challenges in positron emission tomography imaging of gliosis in chronic neuropathic pain. Pain 2024; 165:2184-2199. [PMID: 38713812 DOI: 10.1097/j.pain.0000000000003247] [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: 12/14/2023] [Accepted: 03/05/2024] [Indexed: 05/09/2024]
Abstract
ABSTRACT Understanding the mechanisms that underpin the transition from acute to chronic pain is critical for the development of more effective and targeted treatments. There is growing interest in the contribution of glial cells to this process, with cross-sectional preclinical studies demonstrating specific changes in these cell types capturing targeted timepoints from the acute phase and the chronic phase. In vivo longitudinal assessment of the development and evolution of these changes in experimental animals and humans has presented a significant challenge. Recent technological advances in preclinical and clinical positron emission tomography, including the development of specific radiotracers for gliosis, offer great promise for the field. These advances now permit tracking of glial changes over time and provide the ability to relate these changes to pain-relevant symptomology, comorbid psychiatric conditions, and treatment outcomes at both a group and an individual level. In this article, we summarize evidence for gliosis in the transition from acute to chronic pain and provide an overview of the specific radiotracers available to measure this process, highlighting their potential, particularly when combined with ex vivo / in vitro techniques, to understand the pathophysiology of chronic neuropathic pain. These complementary investigations can be used to bridge the existing gap in the field concerning the contribution of gliosis to neuropathic pain and identify potential targets for interventions.
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Affiliation(s)
- Gaelle M Emvalomenos
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - James W M Kang
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Bianca Jupp
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Kevin A Keay
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Luke A Henderson
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
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2
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Wongso H, Kurniawan A, Setiadi Y, Kusumaningrum CE, Widyasari EM, Wibawa TH, Mahendra I, Febrian MB, Sriyani ME, Halimah I, Daruwati I, Gunawan R, Achmad A, Nugraha DH, Lesmana R, Nugraha AS. Translocator Protein 18 kDa (TSPO): A Promising Molecular Target for Image-Guided Surgery of Solid Cancers. Adv Pharm Bull 2024; 14:86-104. [PMID: 38585455 PMCID: PMC10997928 DOI: 10.34172/apb.2024.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/26/2023] [Accepted: 10/08/2023] [Indexed: 04/09/2024] Open
Abstract
The translocator protein 18-kDa (TSPO) is a mitochondrial membrane protein that is previously identified as the peripheral benzodiazepine receptor (PBR). Furthermore, it plays a significant role in a diverse range of biochemical processes, including steroidogenesis, mitochondrial cholesterol transport, cell survival and death, cell proliferation, and carcinogenesis. Several investigations also reported its roles in various types of cancers, including colorectal, brain, breast, prostate, and lung cancers, as well as melanoma. According to a previous study, the expression of TSPO was upregulated in cancer cells, which corresponds to an aggressive phenotype and/or poor prognosis. Consequently, the potential for crafting diagnostic and prognostic tools with a focus on TSPO holds great potential. In this context, several radioligands designed to target this protein have been identified, and some of the candidates have advanced to clinical trials. In recent years, the use of hybrid probes with radioactive and fluorescence molecules for image-guided surgery has exhibited promising results in animal and human studies. This indicates that the approach can serve as a valuable surgical navigator during cancer surgery. The current hybrid probes are built from various molecular platforms, including small molecules, nanoparticles, and antibodies. Although several TSPO-targeted imaging probes have been developed, their development for image-guided surgery of cancers is still limited. Therefore, this review aims to highlight recent findings on the involvement of TSPO in carcinogenesis, as well as provide a new perspective on the potential application of TSPO-targeted hybrid probes for image-guided surgery.
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Affiliation(s)
- Hendris Wongso
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Ahmad Kurniawan
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Yanuar Setiadi
- Research Center for Environmental and Clean Technology, Research Organization for Life Sciences and Environment, National Research and Innovation Agency, Puspiptek, Banten 15314, Indonesia
| | - Crhisterra E. Kusumaningrum
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Eva M. Widyasari
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Teguh H.A. Wibawa
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Isa Mahendra
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Muhamad B. Febrian
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Maula E. Sriyani
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Iim Halimah
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
| | - Isti Daruwati
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Rudi Gunawan
- Research Center for Radioisotope, Radiopharmaceutical, and Biodosimetry Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency Republic of Indonesia, Puspiptek, Banten 15314, Indonesia
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
| | - Arifudin Achmad
- Research Collaboration Center for Theranostic Radiopharmaceuticals, National Research and Innovation Agency, Jl. Ir. Soekarno KM 21, Jatinangor 45363, Indonesia
- Department of Nuclear Medicine and Molecular Theranostics, Faculty of Medicine, Universitas Padjadjaran, Bandung 40161
- Oncology and Stem Cells Working Group, Faculty of Medicine, Universitas Padjadjaran, Bandung 40161
| | | | - Ronny Lesmana
- Department of Biomedical Science, Faculty of Medicine, Universitas Padjadjaran, Jatinangor 45363, Indonesia
- Physiology Molecular, Division of Biological Activity, Central Laboratory, Universitas Padjadjaran, Jatinangor 45363, Indonesia
- Laboratory of Sciences, Graduate School, Universitas Padjadjaran, Bandung, Indonesia
| | - Ari S. Nugraha
- Drug Utilisation and Discovery Research Group, Faculty of Pharmacy, Universitas Jember, Jember 68121, Indonesia
- School of Chemistry and Molecular Biosciences, Molecular Horizons, University of Wollongong, Wollongong, New South Wales, 2522, Australia
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Chassé M, Pees A, Lindberg A, Liang SH, Vasdev N. Spirocyclic Iodonium Ylides for Fluorine-18 Radiolabeling of Non-Activated Arenes: From Concept to Clinical Research. CHEM REC 2023; 23:e202300072. [PMID: 37183954 DOI: 10.1002/tcr.202300072] [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: 02/24/2023] [Revised: 04/27/2023] [Indexed: 05/16/2023]
Abstract
Positron emission tomography (PET) is a powerful imaging tool for drug discovery, clinical diagnosis, and monitoring of disease progression. Fluorine-18 is the most common radionuclide used for PET, but advances in radiotracer development have been limited by the historical lack of methodologies and precursors amenable to radiolabeling with fluorine-18. Radiolabeling of electron-rich (hetero)aromatic rings remains a long-standing challenge in the production of PET radiopharmaceuticals. In this personal account, we discuss the history of spirocyclic iodonium ylide precursors, from inception to applications in clinical research, for the incorporation of fluorine-18 into complex non-activated (hetero)aromatic rings.
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Affiliation(s)
- Melissa Chassé
- Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, ON M5S 1A8, Canada
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Anna Pees
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Anton Lindberg
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, 30322, USA
| | - Neil Vasdev
- Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, ON M5S 1A8, Canada
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON M5T 1R8, Canada
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4
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D'Anna L, Searle G, Harvey K, Matthews PM, Veltkamp R. Time course of neuroinflammation after human stroke - a pilot study using co-registered PET and MRI. BMC Neurol 2023; 23:193. [PMID: 37193998 DOI: 10.1186/s12883-023-03178-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 03/22/2023] [Indexed: 05/18/2023] Open
Abstract
BACKGROUND Microglial activation contributes to both inflammatory damage and repair in experimental ischemic stroke. However, because of the logistical challenges, there have been few clinical imaging studies directly describing inflammatory activation and its resolution after stroke. The purpose of our pilot study was to describe the spatio-temporal profile of brain inflammation after stroke using 18kD translocator protein (TSPO) positron emission tomography (PET) with magnetic resonance (MR) co-registration in the subacute and chronic stage after stroke. METHODS Three patients underwent magnetic resonance imaging (MRI) and PET scans with TSPO ligand [11C]PBR28 15 ± 3 and 90 ± 7 days after an ischaemic stroke. Regions of interest (ROI) were defined on MRI images and applied to the dynamic PET data to derive regional time-activity curves. Regional uptake was quantified as standardised uptake values (SUV) over 60 to 90 min post-injection. ROI analysis was applied to identify binding in the infarct, and in frontal, temporal, parietal, and occipital lobes and cerebellum excluding the infarcted area. RESULTS The mean age of participants was 56 ± 20.4 years and mean infarct volume was 17.9 ± 18.1 ml. [11C]PBR28 showed increased tracer signal in the infarcted area compared to non-infarcted areas of the brain in the subacute phase of stroke (Patient 1 SUV 1.81; Patient 2 SUV 1.15; Patient 3 SUV 1.64). [11C]PBR28 uptake returned to the level of non-infarcted areas at 90 days Patient 1 SUV 0.99; Patient 3 SUV 0.80). No additional upregulation was detected elsewhere at either time point. CONCLUSIONS The neuroinflammatory reaction after ischaemic stroke is limited in time and circumscribed in space suggesting that post-ischaemic inflammation is tightly controlled but regulatory mechanisms.
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Affiliation(s)
- Lucio D'Anna
- Department of Stroke and Neuroscience, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK
- Department of Brain Sciences, Imperial College London, London, UK
| | | | - Kirsten Harvey
- Department of Brain Sciences, Imperial College London, London, UK
| | - Paul M Matthews
- Department of Brain Sciences, Imperial College London, London, UK
- Dementia Research Institute at Imperial College London, London, UK
| | - Roland Veltkamp
- Department of Brain Sciences, Imperial College London, London, UK.
- Department of Neurology, Alfried-Krupp Krankenhaus Essen, Essen, Germany.
- Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany.
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5
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Witkam RL, Buckens CF, van Goethem JWM, Vissers KCP, Henssen DJHA. The current role and future directions of imaging in failed back surgery syndrome patients: an educational review. Insights Imaging 2022; 13:117. [PMID: 35838802 PMCID: PMC9287525 DOI: 10.1186/s13244-022-01246-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 06/02/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Failed back surgery syndrome (FBSS) is an umbrella term referring to painful sensations experienced by patients after spinal surgery, mostly of neuropathic nature. Adequate treatment of FBSS is challenging, as its etiology is believed to be multifactorial and still not fully clarified. Accurate identification of the source of pain is difficult but pivotal to establish the most appropriate treatment strategy. Although the clinical utility of imaging in FBSS patients is still contentious, objective parameters are highly warranted to map different phenotypes of FBSS and tailor each subsequent therapy. MAIN BODY Since technological developments have weakened the applicability of prior research, this educational review outlined the recent evidence (i.e., from January 2005 onwards) after a systematic literature search. The state of the art on multiple imaging modalities in FBSS patients was reviewed. Future directions related to functional MRI and the development of imaging biomarkers have also been discussed. CONCLUSION Besides the fact that more imaging studies correlated with symptomatology in the postoperative setting are warranted, the current educational review outlined that contrast-enhanced MRI and MR neurography have been suggested as valuable imaging protocols to assess alterations in the spine of FBSS patients. The use of imaging biomarkers to study correlations between imaging features and symptomatology might hold future potential; however, more research is required before any promising hypotheses can be drawn.
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Affiliation(s)
- Richard L Witkam
- Department of Anaesthesiology, Pain and Palliative Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands. .,Department of Neurosurgery, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Constantinus F Buckens
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Johan W M van Goethem
- Department of Medical and Molecular Imaging, General Hospital Nikolaas, Sint-Niklaas, Belgium
| | - Kris C P Vissers
- Department of Anaesthesiology, Pain and Palliative Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Dylan J H A Henssen
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
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6
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Asih PR, Poljak A, Kassiou M, Ke YD, Ittner LM. Differential mitochondrial protein interaction profile between human translocator protein and its A147T polymorphism variant. PLoS One 2022; 17:e0254296. [PMID: 35522669 PMCID: PMC9075623 DOI: 10.1371/journal.pone.0254296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 04/06/2022] [Indexed: 11/19/2022] Open
Abstract
The translocator protein (TSPO) has been implicated in mitochondrial transmembrane cholesterol transport, brain inflammation, and other mitochondrial functions. It is upregulated in glial cells during neuroinflammation in Alzheimer’s disease. High affinity TSPO imaging radioligands are utilized to visualize neuroinflammation. However, this is hampered by the common A147T polymorphism which compromises ligand binding. Furthermore, this polymorphism has been linked to increased risk of neuropsychiatric disorders, and possibly reduces TSPO protein stability. Here, we used immunoprecipitation coupled to mass-spectrometry (IP-MS) to establish a mitochondrial protein binding profile of wild-type (WT) TSPO and the A147T polymorphism variant. Using mitochondria from human glial cells expressing either WT or A147T TSPO, we identified 30 WT TSPO binding partners, yet only 23 for A147T TSPO. Confirming that A147T polymorphism of the TSPO might confer loss of function, we found that one of the identified interactors of WT TSPO, 14-3-3 theta (YWHAQ), a protein involved in regulating mitochondrial membrane proteins, interacts much less with A147T TSPO. Our data presents a network of mitochondrial interactions of TSPO and its A147T polymorphism variant in human glial cells and indicate functional relevance of A147T in mitochondrial protein networks.
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Affiliation(s)
- Prita R. Asih
- Dementia Research Centre, Faculty of Health and Medical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Anne Poljak
- Mark Wainwright Analytical Centre, University of New South Wales, Sydney, Australia
| | - Michael Kassiou
- School of Chemistry, Faculty of Science, University of Sydney, Sydney, NSW, Australia
| | - Yazi D. Ke
- Dementia Research Centre, Faculty of Health and Medical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Lars M. Ittner
- Dementia Research Centre, Faculty of Health and Medical Sciences, Macquarie University, Sydney, NSW, Australia
- * E-mail:
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7
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Wang C, Liu S, Liu F, Bhutta A, Patterson TA, Slikker W. Application of Nonhuman Primate Models in the Studies of Pediatric Anesthesia Neurotoxicity. Anesth Analg 2022; 134:1203-1214. [PMID: 35147575 DOI: 10.1213/ane.0000000000005926] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Numerous animal models have been used to study developmental neurotoxicity associated with short-term or prolonged exposure of common general anesthetics at clinically relevant concentrations. Pediatric anesthesia models using the nonhuman primate (NHP) may more accurately reflect the human condition because of their phylogenetic similarity to humans with regard to reproduction, development, neuroanatomy, and cognition. Although they are not as widely used as other animal models, the contribution of NHP models in the study of anesthetic-induced developmental neurotoxicity has been essential. In this review, we discuss how neonatal NHP animals have been used for modeling pediatric anesthetic exposure; how NHPs have addressed key data gaps and application of the NHP model for the studies of general anesthetic-induced developmental neurotoxicity. The appropriate application and evaluation of the NHP model in the study of general anesthetic-induced developmental neurotoxicity have played a key role in enhancing the understanding and awareness of the potential neurotoxicity associated with pediatric general anesthetics.
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Affiliation(s)
- Cheng Wang
- From the Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, Arkansas
| | - Shuliang Liu
- From the Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, Arkansas
| | - Fang Liu
- From the Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, Arkansas
| | - Adnan Bhutta
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Tucker A Patterson
- Office of the Director, National Center for Toxicological Research/FDA, Jefferson, Arkansas
| | - William Slikker
- Office of the Director, National Center for Toxicological Research/FDA, Jefferson, Arkansas
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Delage C, Vignal N, Guerin C, Taib T, Barboteau C, Mamma C, Khacef K, Margaill I, Sarda-Mantel L, Rizzo-Padoin N, Hontonnou F, Marchand-Leroux C, Lerouet D, Hosten B, Besson V. From positron emission tomography to cell analysis of the 18-kDa Translocator Protein in mild traumatic brain injury. Sci Rep 2021; 11:24009. [PMID: 34907268 PMCID: PMC8671393 DOI: 10.1038/s41598-021-03416-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 11/17/2021] [Indexed: 11/24/2022] Open
Abstract
Traumatic brain injury (TBI) leads to a deleterious neuroinflammation, originating from microglial activation. Monitoring microglial activation is an indispensable step to develop therapeutic strategies for TBI. In this study, we evaluated the use of the 18-kDa translocator protein (TSPO) in positron emission tomography (PET) and cellular analysis to monitor microglial activation in a mild TBI mouse model. TBI was induced on male Swiss mice. PET imaging analysis with [18F]FEPPA, a TSPO radiotracer, was performed at 1, 3 and 7 days post-TBI and flow cytometry analysis on brain at 1 and 3 days post-TBI. PET analysis showed no difference in TSPO expression between non-operated, sham-operated and TBI mice. Flow cytometry analysis demonstrated an increase in TSPO expression in ipsilateral brain 3 days post-TBI, especially in microglia, macrophages, lymphocytes and neutrophils. Moreover, microglia represent only 58.3% of TSPO+ cells in the brain. Our results raise the question of the use of TSPO radiotracer to monitor microglial activation after TBI. More broadly, flow cytometry results point the lack of specificity of TSPO for microglia and imply that microglia contribute to the overall increase in TSPO in the brain after TBI, but is not its only contributor.
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Affiliation(s)
- Clément Delage
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France.
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France.
| | - Nicolas Vignal
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France
- Assistance Publique - Hôpitaux de Paris (AP-HP), Service de Médecine Nucléaire, Hôpital Lariboisière, Paris, France
- Université de Paris, Institut de Recherche Saint-Louis, Unité Claude Kellershohn, Paris, France
| | - Coralie Guerin
- Université de Paris, Innovative Therapies in Haemostasis, Inserm, 75006, Paris, France
- Institut Curie, Cytometry Core, 75005, Paris, France
- Université de Paris, Inserm UMS 3612 CNRS - US25 Inserm -Faculté de Pharmacie de Paris, Paris, France
| | - Toufik Taib
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
| | - Clément Barboteau
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France
| | - Célia Mamma
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
| | - Kahina Khacef
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
| | - Isabelle Margaill
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1140, Paris, France
| | - Laure Sarda-Mantel
- Assistance Publique - Hôpitaux de Paris (AP-HP), Service de Médecine Nucléaire, Hôpital Lariboisière, Paris, France
- Université de Paris, Institut de Recherche Saint-Louis, Unité Claude Kellershohn, Paris, France
| | - Nathalie Rizzo-Padoin
- Université de Paris, Institut de Recherche Saint-Louis, Unité Claude Kellershohn, Paris, France
- CHU de Martinique, Service Pharmacie, Hôpital Pierre Zobda-Quitman, Fort-de-France, France
| | - Fortune Hontonnou
- Université de Paris, Institut de Recherche Saint-Louis, Unité Claude Kellershohn, Paris, France
- Université de Paris, Inserm UMR-S 942, Hôpital Lariboisière, Paris, France
| | - Catherine Marchand-Leroux
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France
| | - Dominique Lerouet
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France
| | - Benoit Hosten
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France
- Université de Paris, Institut de Recherche Saint-Louis, Unité Claude Kellershohn, Paris, France
- Assistance Publique - Hôpitaux de Paris (AP-HP), Service Pharmacie, Hôpital Saint-Louis, Paris, France
| | - Valérie Besson
- Faculté de Pharmacie de Paris, Université Paris Descartes, EA4475 - Pharmacologie de la circulation cérébrale, Paris, France
- Faculté de Pharmacie de Paris, Université de Paris, Inserm UMR-S 1144 - Optimisation Thérapeutique en Neuropsychopharmacologie, 4 avenue de l'Observatoire, 75006, Paris, France
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9
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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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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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11
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Fiorenza D, Nicolai E, Cavaliere C, Fiorino F, Esposito G, Salvatore M. Fully Automated Synthesis of Novel TSPO PET Imaging Ligand [ 18F]Fluoroethyltemazepam. Molecules 2021; 26:2372. [PMID: 33921765 PMCID: PMC8073130 DOI: 10.3390/molecules26082372] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Benzodiazepines, including temazepam are described as TSPO antagonists. In fact, TSPO was initially described as a peripheral benzodiazepine receptor (PBR) with a secondary binding site for diazepam. TSPO is a potential imaging target of neuroinflammation because there is an amplification of the expression of this receptor. OBJECTIVES Herein, we developed a novel fluorinated benzodiazepine ligand, [18F]Fluoroethyltemazepam ([18F]F-FETEM), for positron emission tomography (PET) imaging of translocator protein (18 kDa). METHODS [18F]F-FETEM was radiolabelled with an automated synthesizer via a one-pot procedure. We conducted a [18F]F-aliphatic nucleophilic substitution of a tosylated precursor followed by purification on C18 and Alumina N SPE cartridges. Quality control tests was also carried out. RESULTS We obtained 2.0-3.0% decay-uncorrected radiochemical activity yield (3.7% decay-corrected) within the whole synthesis time about 33 min. The radiochemical purity of [18F]F-FETEM was over 90% by TLC analysis. CONCLUSIONS This automated procedure may be used as basis for future production of [18F]F-FETEM for preclinical PET imaging studies.
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Affiliation(s)
| | | | | | - Ferdinando Fiorino
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (F.F.); (G.E.)
| | - Giovanna Esposito
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (F.F.); (G.E.)
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12
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13
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Werner JM, Lohmann P, Fink GR, Langen KJ, Galldiks N. Current Landscape and Emerging Fields of PET Imaging in Patients with Brain Tumors. Molecules 2020; 25:E1471. [PMID: 32213992 PMCID: PMC7146177 DOI: 10.3390/molecules25061471] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
The number of positron-emission tomography (PET) tracers used to evaluate patients with brain tumors has increased substantially over the last years. For the management of patients with brain tumors, the most important indications are the delineation of tumor extent (e.g., for planning of resection or radiotherapy), the assessment of treatment response to systemic treatment options such as alkylating chemotherapy, and the differentiation of treatment-related changes (e.g., pseudoprogression or radiation necrosis) from tumor progression. Furthermore, newer PET imaging approaches aim to address the need for noninvasive assessment of tumoral immune cell infiltration and response to immunotherapies (e.g., T-cell imaging). This review summarizes the clinical value of the landscape of tracers that have been used in recent years for the above-mentioned indications and also provides an overview of promising newer tracers for this group of patients.
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Affiliation(s)
- Jan-Michael Werner
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener St. 62, 50937 Cologne, Germany; (J.-M.W.); (G.R.F.)
| | - Philipp Lohmann
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Leo-Brandt-St., 52425 Juelich, Germany; (P.L.); (K.-J.L.)
| | - Gereon R. Fink
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener St. 62, 50937 Cologne, Germany; (J.-M.W.); (G.R.F.)
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Leo-Brandt-St., 52425 Juelich, Germany; (P.L.); (K.-J.L.)
| | - Karl-Josef Langen
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Leo-Brandt-St., 52425 Juelich, Germany; (P.L.); (K.-J.L.)
- Department of Nuclear Medicine, University Hospital Aachen, 52074 Aachen, Germany
| | - Norbert Galldiks
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener St. 62, 50937 Cologne, Germany; (J.-M.W.); (G.R.F.)
- Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Leo-Brandt-St., 52425 Juelich, Germany; (P.L.); (K.-J.L.)
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14
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Zimmer L. [PET imaging for better understanding of normal and pathological neurotransmission]. Biol Aujourdhui 2019; 213:109-120. [PMID: 31829931 DOI: 10.1051/jbio/2019025] [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: 09/17/2019] [Indexed: 11/14/2022]
Abstract
Positron emission tomography imaging is still an expanding field of preclinical and clinical investigations exploring the brain and its normal and pathological functions. In addition to technological improvements in PET scanners, the availability of suitable radiotracers for unexplored pharmacological targets is a key factor in this expansion. Many radiotracers (or radiopharmaceuticals, when administered to humans) have been developed by multidisciplinary teams to visualize and quantify a growing numbers of brain receptors, transporters, enzymes and other targets. The development of new PET radiotracers still represents an exciting challenge, given the large number of neurochemical functions that remain to be explored. In this article, we review the development context of the first preclinical radiotracers and their passage to humans. The main current contributions of PET radiotracers are described in terms of imaging neuronal metabolism, quantification of receptors and transporters, neurodegenerative and neuroinflammatory imaging. The different approaches to functional imaging of neurotransmission are also discussed. Finally, the contributions of PET imaging to the research and development of new brain drugs are described.
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Affiliation(s)
- Luc Zimmer
- Centre de Recherche en Neurosciences de Lyon (CNRS - INSERM - Université Claude Bernard Lyon 1), Lyon, France - CERMEP-Imagerie du Vivant, Hospices Civils de Lyon, Bron, France - Institut National des Sciences et Techniques Nucléaires, CEA, Saclay, France
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15
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Real CC, Doorduin J, Kopschina Feltes P, Vállez García D, de Paula Faria D, Britto LR, de Vries EF. Evaluation of exercise-induced modulation of glial activation and dopaminergic damage in a rat model of Parkinson's disease using [ 11C]PBR28 and [ 18F]FDOPA PET. J Cereb Blood Flow Metab 2019; 39:989-1004. [PMID: 29271291 PMCID: PMC6545619 DOI: 10.1177/0271678x17750351] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Evidence suggests that exercise can modulate neuroinflammation and neuronal damage. We evaluated if such effects of exercise can be detected with positron emission tomography (PET) in a rat model of Parkinson's disease (PD). Rats were unilaterally injected in the striatum with 6-hydroxydopamine (PD rats) or saline (controls) and either remained sedentary (SED) or were forced to exercise three times per week for 40 min (EX). Motor and cognitive functions were evaluated by the open field, novel object recognition, and cylinder tests. At baseline, day 10 and 30, glial activation and dopamine synthesis were assessed by [11C]PBR28 and [18F]FDOPA PET, respectively. PET data were confirmed by immunohistochemical analysis of microglial (Iba-1) / astrocyte (GFAP) activation and tyrosine hydroxylase (TH). [11C]PBR28 PET showed increased glial activation in striatum and hippocampus of PD rats at day 10, which had resolved at day 30. Exercise completely suppressed glial activation. Imaging results correlated well with post-mortem Iba-1 staining, but not with GFAP staining. [18F]FDOPA PET, TH staining and behavioral tests indicate that 6-OHDA caused damage to dopaminergic neurons, which was partially prevented by exercise. These results show that exercise can modulate toxin-induced glial activation and neuronal damage, which can be monitored noninvasively by PET.
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Affiliation(s)
- Caroline C Real
- 1 Laboratory of Cellular Neurobiology, Department of Physiology and Biophysics, University of São Paulo, São Paulo, SP, Brazil.,2 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,3 Laboratory of Nuclear Medicine (LIM 43), University of São Paulo Medical School, University of São Paulo, São Paulo, Brazil
| | - Janine Doorduin
- 2 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Paula Kopschina Feltes
- 2 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - David Vállez García
- 2 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Daniele de Paula Faria
- 3 Laboratory of Nuclear Medicine (LIM 43), University of São Paulo Medical School, University of São Paulo, São Paulo, Brazil
| | - Luiz R Britto
- 1 Laboratory of Cellular Neurobiology, Department of Physiology and Biophysics, University of São Paulo, São Paulo, SP, Brazil
| | - Erik Fj de Vries
- 2 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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16
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Walters JL, Zhang X, Talpos JC, Fogle CM, Li M, Chelonis JJ, Paule MG. Sevoflurane exposure has minimal effect on cognitive function and does not alter microglial activation in adult monkeys. Neurotoxicology 2018; 71:159-167. [PMID: 30605762 DOI: 10.1016/j.neuro.2018.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/10/2018] [Accepted: 12/26/2018] [Indexed: 12/19/2022]
Abstract
Postoperative Cognitive Dysfunction (POCD) is a complication that has been observed in a subset of adult and elderly individuals after general anesthesia and surgery. Although the pathogenesis of POCD is largely unknown, a growing body of preclinical research suggests that POCD may be caused by general anesthesia. A significant amount of research has examined the effects of general anesthesia on neurocognitive function in rodents, yet no studies have assessed the adverse effects of general anesthesia on brain function in adult nonhuman primates. Thus, this study sought to determine the effects of an extended exposure to sevoflurane anesthesia on cognitive function and neural inflammation in adult rhesus macaques. Five adult rhesus macaques (16-17 years of age) were exposed to sevoflurane anesthesia for 8 h and, and micro-positron emission tomography (PET)/computed tomography (CT) imaging and a battery of operant tasks were used to assess the effects of anesthesia exposure on 18F-labeled fluoroethoxybenzyl-N-(4-phenoxypyridin-3-yl) acetamide ([18F]-FEPPA) uptake, a biomarker of microglia activation, and aspects of complex cognitive function. Exposure to sevoflurane anesthesia for 8 h did not increase [18F]-FEPPA uptake in the adult monkey brain. Sevoflurane anesthesia significantly decreased accuracy (mean difference = 22.79) on a learning acquisition task 6 days after exposure [t(3) = 6.92, p = 0.006], but this effect did not persist when measured 1 week and 2 weeks after additional exposures. Further, sevoflurane anesthesia had no impact on performance in 4 additional cognitive tasks. These data suggest that exposure to anesthesia alone may not be sufficient to cause persistent POCD in adult populations.
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Affiliation(s)
- Jennifer L Walters
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States
| | - Xuan Zhang
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States
| | - John C Talpos
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States.
| | - Charles M Fogle
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States
| | - Mi Li
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States
| | - John J Chelonis
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States
| | - Merle G Paule
- National Center for Toxicological Research (NCTR)/FDA, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, AR, 72079, United States
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17
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Airas L, Nylund M, Rissanen E. Evaluation of Microglial Activation in Multiple Sclerosis Patients Using Positron Emission Tomography. Front Neurol 2018; 9:181. [PMID: 29632509 PMCID: PMC5879102 DOI: 10.3389/fneur.2018.00181] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/08/2018] [Indexed: 01/24/2023] Open
Abstract
Understanding the mechanisms underlying progression in multiple sclerosis (MS) is one of the key elements contributing to the identification of appropriate therapeutic targets for this under-managed condition. In addition to plaque-related focal inflammatory pathology typical for relapsing remitting MS there are, in progressive MS, widespread diffuse alterations in brain areas outside the focal lesions. This diffuse pathology is tightly related to microglial activation and is co-localized with signs of neurodegeneration. Microglia are brain-resident cells of the innate immune system and overactivation of microglia is associated with several neurodegenerative diseases. Understanding the role of microglial activation in relation to developing neurodegeneration and disease progression may provide a key to developing therapies to target progressive MS. 18-kDa translocator protein (TSPO) is a mitochondrial molecule upregulated in microglia upon their activation. Positron emission tomography (PET) imaging using TSPO-binding radioligands provides a method to assess microglial activation in patients in vivo. In this mini-review, we summarize the current status of TSPO imaging in the field of MS. In addition, the review discusses new insights into the potential use of this method in treatment trials and in clinical assessment of progressive MS.
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Affiliation(s)
- Laura Airas
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Marjo Nylund
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
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18
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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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19
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Vomacka L, Albert NL, Lindner S, Unterrainer M, Mahler C, Brendel M, Ermoschkin L, Gosewisch A, Brunegraf A, Buckley C, Kümpfel T, Rupprecht R, Ziegler S, Kerschensteiner M, Bartenstein P, Böning G. TSPO imaging using the novel PET ligand [ 18F]GE-180: quantification approaches in patients with multiple sclerosis. EJNMMI Res 2017; 7:89. [PMID: 29150726 PMCID: PMC5693838 DOI: 10.1186/s13550-017-0340-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/20/2017] [Indexed: 01/12/2023] Open
Abstract
Background PET ligands targeting the translocator protein (TSPO) represent promising tools to visualise neuroinflammation. Here, we analysed parameters obtained in dynamic and static PET images using the novel TSPO ligand [18F]GE-180 in patients with relapsing remitting multiple sclerosis (RRMS) and an approach for semi-quantitative assessment of this disease in clinical routine. Seventeen dynamic [18F]GE-180 PET scans of RRMS patients were evaluated (90 min). A pseudo-reference region (PRR) was defined after identification of the least disease-affected brain area by voxel-based comparison with six healthy controls (HC) and upon exclusion of voxels suspected of being affected in static 60–90 min p.i. images. Standardised uptake value ratios (SUVR) obtained from static images normalised to PRR were correlated to the distribution volume ratios (DVR) derived from dynamic data with Logan reference tissue model. Results Group comparison with HC revealed white matter and thalamus as most affected regions. Fewest differences were found in grey matter, and normalisation to frontal cortex (FC) yielded the greatest reduction in variability of healthy grey and white matter. Hence, FC corrected for affected voxels was chosen as PRR, leading to time-activity curves of FC which were congruent to HC data (SUV60–90 0.37, U test P = 0.42). SUVR showed a very strong correlation with DVR (Pearson ρ > 0.9). Focal MS lesions exhibited a high SUVR (range, 1.3–3.2). Conclusions This comparison with parameters from dynamic data suggests that SUVR normalised to corrected frontal cortex as PRR is suitable for the quantification of [18F]GE-180 uptake in lesions and different brain regions of RRMS patients. This efficient diagnostic protocol based on static [18F]GE-180 PET scans acquired 60–90 min p.i. allows the semi-quantitative assessment of neuroinflammation in RRMS patients in clinical routine.
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Affiliation(s)
- Lena Vomacka
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.
| | - Nathalie Lisa Albert
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | - Marcus Unterrainer
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | - Christoph Mahler
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | - Larissa Ermoschkin
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | - Astrid Gosewisch
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | - Anika Brunegraf
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | | | - Tania Kümpfel
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Sibylle Ziegler
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
| | - Martin Kerschensteiner
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Guido Böning
- Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
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20
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Chen J, Wang Z, Zheng Z, Chen Y, Khor S, Shi K, He Z, Wang Q, Zhao Y, Zhang H, Li X, Li J, Yin J, Wang X, Xiao J. Neuron and microglia/macrophage-derived FGF10 activate neuronal FGFR2/PI3K/Akt signaling and inhibit microglia/macrophages TLR4/NF-κB-dependent neuroinflammation to improve functional recovery after spinal cord injury. Cell Death Dis 2017; 8:e3090. [PMID: 28981091 PMCID: PMC5682656 DOI: 10.1038/cddis.2017.490] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/07/2017] [Accepted: 08/28/2017] [Indexed: 01/09/2023]
Abstract
Therapeutics used to treat central nervous system (CNS) injury were designed to repair neurites and inhibit cell apoptosis. Previous studies have shown that neuron-derived FGF10 exerts potential neuroprotective effects after cerebral ischemia injury. However, little is known about the role of endogenous FGF10 in the recovery process after spinal cord injury (SCI). In this study, we found that FGF10 is mainly produced by neuron and microglia/macrophages, and its expression is increased after SCI. Exogenous treatment of FGF10 improved functional recovery after injury by reducing apoptosis, as well as repairing neurites via FGFR2/PI3K/Akt pathway. On another hand, inhibiting the PI3K/Akt pathway with LY294002 partially reversed the therapeutic effects of FGF10. In addition, small interfering RNA knockdown of FGFR2 suppressed PI3K/Akt pathway activation by FGF10 and abolished its anti-apoptotic and neurite repair effects in vitro. Furthermore, FGF10 treatment inhibited the activation and proliferation of microglia/macrophages through regulation of TLR4/NF-κB pathway, and attenuated the release of pro-inflammatory cytokines after SCI. Thus, the increased expression of FGF10 after acute SCI is an endogenous self-protective response, suggesting that FGF10 could be a potential treatment for CNS injury.
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Affiliation(s)
- Jian Chen
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Zhouguang Wang
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - ZengMing Zheng
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.,Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yu Chen
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Sinan Khor
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - KeSi Shi
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - ZiLi He
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Qingqing Wang
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yingzheng Zhao
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Hongyu Zhang
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xiaokun Li
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Jiawei Li
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jiayu Yin
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xiangyang Wang
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jian Xiao
- Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.,Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
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21
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The macrophage marker translocator protein (TSPO) is down-regulated on pro-inflammatory 'M1' human macrophages. PLoS One 2017; 12:e0185767. [PMID: 28968465 PMCID: PMC5624624 DOI: 10.1371/journal.pone.0185767] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/19/2017] [Indexed: 12/14/2022] Open
Abstract
The translocator protein (TSPO) is a mitochondrial membrane protein, of as yet uncertain function. Its purported high expression on activated macrophages, has lent utility to TSPO targeted molecular imaging in the form of positron emission tomography (PET), as a means to detect and quantify inflammation in vivo. However, existing literature regarding TSPO expression on human activated macrophages is lacking, mostly deriving from brain tissue studies, including studies of brain malignancy, and inflammatory diseases such as multiple sclerosis. Here, we utilized three human sources of monocyte derived macrophages (MDM), from THP-1 monocytes, healthy peripheral blood monocytes and synovial fluid monocytes from patients with rheumatoid arthritis, to undertake a detailed investigation of TSPO expression in activated macrophages. In this work, we demonstrate a consistent down-regulation of TSPO mRNA and protein in macrophages activated to a pro-inflammatory, or ‘M1’ phenotype. Conversely, stimulation of macrophages to an M2 phenotype with IL-4, dexamethasone or TGF-β1 did not alter TSPO expression, regardless of MDM source. The reasons for this are uncertain, but our study findings add some supporting evidence for recent investigations concluding that TSPO may be involved in negative regulation of inflammatory responses in macrophages.
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22
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Bridging Autism Spectrum Disorders and Schizophrenia through inflammation and biomarkers - pre-clinical and clinical investigations. J Neuroinflammation 2017; 14:179. [PMID: 28870209 PMCID: PMC5584030 DOI: 10.1186/s12974-017-0938-y] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 08/08/2017] [Indexed: 12/15/2022] Open
Abstract
In recent years, evidence supporting a link between inflammation and neuropsychiatric disorders has been mounting. Autism spectrum disorders (ASD) and schizophrenia share some clinical similarities which we hypothesize might reflect the same biological basis, namely, in terms of inflammation. However, the diagnosis of ASD and schizophrenia relies solely on clinical symptoms, and to date, there is no clinically useful biomarker to diagnose or monitor the course of such illnesses. The focus of this review is the central role that inflammation plays in ASD and schizophrenia. It spans from pre-clinical animal models to clinical research and excludes in vitro studies. Four major areas are covered: (1) microglia, the inflammatory brain resident myeloid cells, (2) biomarkers, including circulating cytokines, oxidative stress markers, and microRNA players, known to influence cellular processes at brain and immune levels, (3) effect of anti-psychotics on biomarkers and other predictors of response, and (4) impact of gender on response to immune activation, biomarkers, and response to anti-psychotic treatments.
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23
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Alam MM, Lee J, Lee SY. Recent Progress in the Development of TSPO PET Ligands for Neuroinflammation Imaging in Neurological Diseases. Nucl Med Mol Imaging 2017; 51:283-296. [PMID: 29242722 DOI: 10.1007/s13139-017-0475-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/08/2016] [Accepted: 02/06/2017] [Indexed: 12/13/2022] Open
Abstract
Neuroinflammation is heavily associated with various neurological diseases including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. It is strongly characterized by the activation of microglia which can be visualized using position emission tomography (PET). Traditionally, translocator protein 18 kDa (TSPO) has been the preferred target for imaging the inflammatory progression of the microglial component. TSPO is expressed in the outer mitochondrial membrane and present in very low concentrations in the healthy human brain, but is markedly upregulated in response to brain injury and inflammation. Due to its value as a marker of microglial activation and subsequent utility for evaluating neuroinflammation in CNS disorders, several classes of TSPO radioligands have been developed and evaluated. However, the application of these second-generation TSPO radiotracers has been subject to several limiting factors, including a polymorphism that affects TSPO binding. This review focuses on recent developments in TSPO imaging, as well as current limitations and suggestions for future directions from a medical imaging perspective.
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Affiliation(s)
- Md Maqusood Alam
- Neuroscience Research Institute, Gachon University, Incheon, 20565 South Korea
| | - Jihye Lee
- Neuroscience Research Institute, Gachon University, Incheon, 20565 South Korea
| | - Sang-Yoon Lee
- Neuroscience Research Institute, Gachon University, Incheon, 20565 South Korea.,Department of Neuroscience, College of Medicine, Gachon University, Incheon, 21936 South Korea
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24
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Abstract
PET allows noninvasive imaging of a variety of events in the body, including the activity of neuronal circuits in the brain that are involved in cognition and behaviors, by using radiotracers that detect relevant biological reactions. A major impediment to expanding PET applications to study the brain has been the lack of radiotracers that can identify and measure specific types of neurons or glial cells. In this issue of the JCI, Van de Bittner and colleagues describe a promising step toward solving this problem by identifying and describing a radiotracer, [11C]GV1-57, that appears to specifically label olfactory sensory neurons (OSNs), which are essential for olfaction (Figure 1). This tracer, if its specificity is confirmed, has the potential to become a prototype for future radiotracers that can identify other neuronal cell types and would allow visualization and in-depth characterization of these neurons and their genesis.
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25
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Zhang X, Liu F, Slikker W, Wang C, Paule MG. Minimally invasive biomarkers of general anesthetic-induced developmental neurotoxicity. Neurotoxicol Teratol 2016; 60:95-101. [PMID: 27784630 DOI: 10.1016/j.ntt.2016.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/29/2016] [Accepted: 10/21/2016] [Indexed: 12/22/2022]
Abstract
The association of general anesthesia with developmental neurotoxicity, while nearly impossible to study in pediatric populations, is clearly demonstrable in a variety of animal models from rodents to nonhuman primates. Nearly all general anesthetics tested have been shown to cause abnormal brain cell death in animals when administered during periods of rapid brain growth. The ability to repeatedly assess in the same subjects adverse effects induced by general anesthetics provides significant power to address the time course of important events associated with exposures. Minimally-invasive procedures provide the opportunity to bridge the preclinical/clinical gap by providing the means to more easily translate findings from the animal laboratory to the human clinic. Positron Emission Tomography or PET is a tool with great promise for realizing this goal. PET for small animals (microPET) is providing valuable data on the life cycle of general anesthetic induced neurotoxicity. PET radioligands (annexin V and DFNSH) targeting apoptotic processes have demonstrated that a single bout of general anesthesia effected during a vulnerable period of CNS development can result in prolonged apoptotic signals lasting for several weeks in the rat. A marker of cellular proliferation (FLT) has demonstrated in rodents that general anesthesia-induced inhibition of neural progenitor cell proliferation is evident when assessed a full 2weeks after exposure. Activated glia express Translocator Protein (TSPO) which can be used as a marker of presumed neuroinflammatory processes and a PET ligand for the TSPO (FEPPA) has been used to track this process in both rat and nonhuman primate models. It has been shown that single bouts of general anesthesia can result in elevated TSPO expression lasting for over a week. These examples demonstrate the utility of specific PET tracers to inform, in a minimally-invasive fashion, processes associated with general anesthesia-induced developmental neurotoxicity. The fact that PET procedures are also used clinically suggests an opportunity to confirm in humans what has been repeatedly observed in animals.
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26
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In Vivo Monitoring of Sevoflurane-induced Adverse Effects in Neonatal Nonhuman Primates Using Small-animal Positron Emission Tomography. Anesthesiology 2016; 125:133-46. [DOI: 10.1097/aln.0000000000001154] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Abstract
Background
Animals exposed to sevoflurane during development sustain neuronal cell death in their developing brains. In vivo micro-positron emission tomography (PET)/computed tomography imaging has been utilized as a minimally invasive method to detect anesthetic-induced neuronal adverse effects in animal studies.
Methods
Neonatal rhesus monkeys (postnatal day 5 or 6, 3 to 6 per group) were exposed for 8 h to 2.5% sevoflurane with or without acetyl-l-carnitine (ALC). Control monkeys were exposed to room air with or without ALC. Physiologic status was monitored throughout exposures. Depth of anesthesia was monitored using quantitative electroencephalography. After the exposure, microPET/computed tomography scans using 18F-labeled fluoroethoxybenzyl-N-(4-phenoxypyridin-3-yl) acetamide (FEPPA) were performed repeatedly on day 1, 1 and 3 weeks, and 2 and 6 months after exposure.
Results
Critical physiologic metrics in neonatal monkeys remained within the normal range during anesthetic exposures. The uptake of [18F]-FEPPA in the frontal and temporal lobes was increased significantly 1 day or 1 week after exposure, respectively. Analyses of microPET images recorded 1 day after exposure showed that sevoflurane exposure increased [18F]-FEPPA uptake in the frontal lobe from 0.927 ± 0.04 to 1.146 ± 0.04, and in the temporal lobe from 0.859 ± 0.05 to 1.046 ± 0.04 (mean ± SE, P < 0.05). Coadministration of ALC effectively blocked the increase in FEPPA uptake. Sevoflurane-induced adverse effects were confirmed by histopathologic evidence as well.
Conclusions
Sevoflurane-induced general anesthesia during development increases glial activation, which may serve as a surrogate for neurotoxicity in the nonhuman primate brain. ALC is a potential protective agent against some of the adverse effects associated with such exposures.
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27
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Toyohara J, Sakata M, Hatano K, Yanai S, Endo S, Ishibashi K, Wagatsuma K, Ishii K, Ishiwata K. Preclinical and first-in-man studies of [(11)C]CB184 for imaging the 18-kDa translocator protein by positron emission tomography. Ann Nucl Med 2016; 30:534-43. [PMID: 27329083 DOI: 10.1007/s12149-016-1094-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/30/2016] [Indexed: 01/17/2023]
Abstract
OBJECTIVE We performed preclinical and first-in-man clinical positron emission tomography (PET) studies in human brain using N,N-di-n-propyl-2-[2-(4-[(11)C]methoxyphenyl)-6,8-dichloroimidazol[1,2-a]pyridine-3-yl]acetamide ([(11)C]CB184) to image the 18-kDa translocator protein (TSPO), which is overexpressed in activated microglia in neuroinflammatory conditions. METHODS In vitro selectivity of CB184 was characterized. The radiation absorbed dose by [(11)C]CB184 in humans was calculated from murine distribution data. Acute toxicity of CB184 hydrochloride in rats at a dose of 5.81 mg/kg body weight, which is >10,000-fold higher than the clinical equivalent dose of [(11)C]CB184, was evaluated. Acute toxicity of [(11)C]CB184 injection of a 400-fold dose to administer a postulated dose of 740 MBq [(11)C]CB184 was also evaluated after the decay-out of (11)C. The mutagenicity of CB184 was studied with a reverse mutation test (Ames test). The pharmacological effect of CB184 injection in mice was studied with an open field test. The first PET imaging of TSPO with [(11)C]CB184 in a normal human volunteer was performed. RESULTS A suitable preparation method for [(11)C]CB184 injection was established. CB184 showed low activity in a 28-standard receptor binding profile. The radiation absorbed dose by [(11)C]CB184 in humans was sufficiently low for clinical use, and no acute toxicity of CB184 or [(11)C]CB184 injection was found. No mutagenicity or apparent effect on locomotor activity or anxiety status was observed for CB184. We safely performed brain imaging with PET following administration of [(11)C]CB184 in a normal human volunteer. A 90-min dynamic scan showed rapid initial uptake of radioactivity in the brain followed by prompt clearance. [(11)C]CB184 was homogeneously distributed in the gray matter. The total distribution volume of [(11)C]CB184 was highest in the thalamus followed by the cerebellar cortex and elsewhere. Although regional differences were small, the observed [(11)C]CB184 binding pattern was consistent with the TSPO distribution in normal human brain. Peripherally, [(11)C]CB184 was metabolized in humans: 30 % of the radioactivity in plasma was detected as the unchanged form after 60 min. CONCLUSIONS [(11)C]CB184 is suitable for imaging TSPO in human brain and provides an acceptable radiation dose. Pharmacological safety was noted at the dose required for PET imaging.
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Affiliation(s)
- Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.
| | - Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kentaro Hatano
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Shuichi Yanai
- Research Team for Aging Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Shogo Endo
- Research Team for Aging Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Kenji Ishibashi
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kei Wagatsuma
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kenji Ishii
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kiichi Ishiwata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.,Institute of Cyclotron and Drug Discovery Research, Southern Tohoku Research Institute for Neuroscience, Koriyama, Japan.,Department of Biofunctional Imaging, Fukushima Medical University, Fukushima, Japan
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28
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Abstract
Ten percent to 15% of glucose used by the brain is metabolized nonoxidatively despite adequate tissue oxygenation, a process termed aerobic glycolysis (AG). Because of the known role of glycolysis in biosynthesis, we tested whether learning-induced synaptic plasticity would lead to regionally appropriate, learning-dependent changes in AG. Functional MRI (fMRI) before, during, and after performance of a visual-motor adaptation task demonstrated that left Brodmann area 44 (BA44) played a key role in adaptation, with learning-related changes to activity during the task and altered resting-state, functional connectivity after the task. PET scans before and after task performance indicated a sustained increase in AG in left BA 44 accompanied by decreased oxygen consumption. Intersubject variability in behavioral adaptation rate correlated strongly with changes in AG in this region, as well as functional connectivity, which is consistent with a role for AG in synaptic plasticity.
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29
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A Novel PET Imaging Probe for the Detection and Monitoring of Translocator Protein 18 kDa Expression in Pathological Disorders. Sci Rep 2016; 6:20422. [PMID: 26853260 PMCID: PMC4745082 DOI: 10.1038/srep20422] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/04/2016] [Indexed: 11/16/2022] Open
Abstract
A new fluorine-substituted ligand, compound 1 (CB251), with a very high affinity (Ki = 0.27 ± 0.09 nM) and selectivity for the 18-kDa translocator protein (TSPO), is presented as an attractive biomarker for the diagnosis of neuroinflammation, neurodegeneration and tumour progression. To test compound 1 as a TSPO PET imaging agent in vivo, 2-(2-(4-(2-[18F]fluoroethoxy)phenyl)-6,8-dichloroimidazo[1,2-a]pyridin-3-yl)-N,N-dipropylacetamide ([18F]1; [18F]CB251) was synthesized by nucleophilic aliphatic substitution in a single-step radiolabelling procedure with a 11.1 ± 3.5% (n = 14, decay corrected) radiochemical yield and over 99% radiochemical purity. In animal PET imaging studies, [18F]CB251 provided a clearly visible image of the inflammatory lesion with the binding potential of the specifically bound radioligand relative to the non-displaceable radioligand in tissue (BPND 1.83 ± 0.18), in a neuroinflammation rat model based on the unilateral stereotaxic injection of lipopolysaccharide (LPS), comparable to that of [11C]PBR28 (BPND 1.55 ± 0.41). [18F]CB251 showed moderate tumour uptake (1.96 ± 0.11%ID/g at 1 h post injection) in human glioblastoma U87-MG xenografts. These results suggest that [18F]CB251 is a promising TSPO PET imaging agent for neuroinflammation and TSPO-rich cancers.
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30
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Parente A, Feltes PK, Vállez García D, Sijbesma JW, Moriguchi Jeckel CM, Dierckx RA, de Vries EF, Doorduin J. Pharmacokinetic Analysis of 11C-PBR28 in the Rat Model of Herpes Encephalitis: Comparison with (R)-11C-PK11195. J Nucl Med 2016; 57:785-91. [DOI: 10.2967/jnumed.115.165019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/04/2015] [Indexed: 01/21/2023] Open
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31
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Combined behavioral studies and in vivo imaging of inflammatory response and expression of mGlu5 receptors in schnurri-2 knockout mice. Neurosci Lett 2015; 609:159-64. [DOI: 10.1016/j.neulet.2015.10.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/21/2015] [Accepted: 10/12/2015] [Indexed: 01/23/2023]
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32
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Airas L, Rissanen E, Rinne JO. Imaging neuroinflammation in multiple sclerosis using TSPO-PET. Clin Transl Imaging 2015; 3:461-473. [PMID: 27331049 PMCID: PMC4887541 DOI: 10.1007/s40336-015-0147-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 09/22/2015] [Indexed: 12/15/2022]
Abstract
Conventional MR imaging (MRI) techniques form the cornerstone of multiple sclerosis (MS) diagnostics and clinical follow-up today. MRI is sensitive in demonstrating focal inflammatory lesions and diffuse atrophy. However, especially in progressive MS, there is increasingly widespread diffuse pathology also outside the plaques, often related to microglial activation and neurodegeneration. This cannot be detected using conventional MRI. Positron emission tomography (PET) imaging using 18-kDa translocator protein (TSPO) binding radioligands has recently shown promise as a tool to detect this diffuse pathology in vivo, and for the first time allows one to follow its development longitudinally. It is becoming evident that the more advanced the MS disease is, the more pronounced is microglial activation. PET imaging allows the detection of MS-related pathology at molecular level in vivo. It has potential to enable measurement of effects of new disease-modifying drugs aimed at reducing neurodegeneration and neuroinflammation. PET imaging could thus be included in the design of future clinical trials of progressive MS. There are still technical issues related to the quality of TSPO radioligands and post-processing methodology, and comparison of studies from different PET centres is challenging. In this review, we summarise the main evidence supporting the use of TSPO-PET as a tool to explore the diffuse inflammation in MS.
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Affiliation(s)
- Laura Airas
- Division of Clinical Neurosciences, Turku University Hospital, Kiinamyllynkatu 4-8, 20521 Turku, Finland
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Division of Clinical Neurosciences, Turku University Hospital, Kiinamyllynkatu 4-8, 20521 Turku, Finland
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Juha O. Rinne
- Division of Clinical Neurosciences, Turku University Hospital, Kiinamyllynkatu 4-8, 20521 Turku, Finland
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
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Vállez Garcia D, de Vries EFJ, Toyohara J, Ishiwata K, Hatano K, Dierckx RAJO, Doorduin J. Evaluation of [(11)C]CB184 for imaging and quantification of TSPO overexpression in a rat model of herpes encephalitis. Eur J Nucl Med Mol Imaging 2015; 42:1106-18. [PMID: 25771904 PMCID: PMC4424274 DOI: 10.1007/s00259-015-3021-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/16/2015] [Indexed: 02/04/2023]
Abstract
Purpose Evaluation of translocator protein (TSPO) overexpression is considered an attractive research tool for monitoring neuroinflammation in several neurological and psychiatric disorders. [11C]PK11195 PET imaging has been widely used for this purpose. However, it has a low sensitivity and a poor signal-to-noise ratio. For these reasons, [11C]CB184 was evaluated as a potentially more sensitive PET tracer. Methods A model of herpes simplex encephalitis (HSE) was induced in male Wistar rats. On day 6 or 7 after virus inoculation, [11C]CB184 PET scans were acquired followed by ex vivo evaluation of biodistribution. In addition, [11C]CB184 and [11C]PK11195 PET scans with arterial blood sampling were acquired to generate input for pharmacokinetic modelling. Differences between the saline-treated control group and the virus-treated HSE group were explored using volumes of interest and voxel-based analysis. Results The biodistribution study showed significantly higher [11C]CB184 uptake in the amygdala, olfactory bulb, medulla, pons and striatum (p < 0.05) in HSE rats than in control rats, and the voxel-based analysis showed higher bilateral uptake in the pons and medulla (p < 0.05, corrected at the cluster level). A high correlation was found between tracer uptake in the biodistribution study and on the PET scans (p < 0.001, r2 = 0.71). Pretreatment with 5 mg/kg of unlabelled PK11195 effectively reduced (p < 0.001) [11C]CB184 uptake in the whole brain. Both, [11C]CB184 and [11C]PK11195, showed similar amounts of metabolites in plasma, and the binding potential (BPND) was not significantly different between the HSE rats and the control rats. In HSE rats BPND for [11C]CB184 was significantly higher (p < 0.05) in the amygdala, hypothalamus, medulla, pons and septum than in control rats, whereas higher uptake of [11C]PK11195 was only detected in the medulla. Conclusion [11C]CB184 showed nonspecific binding to healthy tissue comparable to that observed for [11C]PK11195, but it displayed significantly higher specific binding in those brain regions affected by the HSE. Our results suggest that [11C]CB184 PET is a good alternative for imaging of neuroinflammatory processes.
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Affiliation(s)
- David Vállez Garcia
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands,
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Kenk M, Selvanathan T, Rao N, Suridjan I, Rusjan P, Remington G, Meyer JH, Wilson AA, Houle S, Mizrahi R. Imaging neuroinflammation in gray and white matter in schizophrenia: an in-vivo PET study with [18F]-FEPPA. Schizophr Bull 2015; 41:85-93. [PMID: 25385788 PMCID: PMC4266311 DOI: 10.1093/schbul/sbu157] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Neuroinflammation and abnormal immune responses have been implicated in schizophrenia (SCZ). Past studies using positron emission tomography (PET) that examined neuroinflammation in patients with SCZ in vivo using the translocator protein 18kDa (TSPO) target were limited by the insensitivity of the first-generation imaging agent [(11)C]-PK11195, scanners used, and the small sample sizes studied. Present study uses a novel second-generation TSPO PET radioligand N-acetyl-N-(2-[(18)F]fluoroethoxybenzyl)-2-phenoxy-5-pyridinamine ([(18)F]-FEPPA) to evaluate whether there is increased neuroinflammation in patients with SCZ. A cross-sectional study was performed using [(18)F]-FEPPA and a high-resolution research tomograph (HRRT). Eighteen patients with SCZ with ongoing psychotic symptoms and 27 healthy volunteers (HV) were recruited from a tertiary psychiatric clinical setting and the community, respectively. All participants underwent [(18)F]-FEPPA PET and magnetic resonance imaging, and PET data were analyzed to obtain [(18)F]-FEPPA total volume of distribution (VT) using a 2-tissue compartment model with an arterial plasma input function, as previously validated. All subjects were classified as high-, medium- or low-affinity [(18)F]-FEPPA binders on the basis of rs6971 polymorphism, and genotype information was incorporated into the analyses of imaging outcomes. No significant differences in neuroinflammation indexed as [(18)F]-FEPPA VT were observed between groups in either gray (F(1,39) = 0.179, P = .674) or white matter regions (F(1,38) = 0.597, P = .445). The lack of significant difference in neuroinflammation in treated patients with SCZ in the midst of a psychotic episode and HV suggests that neuroinflammatory processes may take place early in disease progression or are affected by antipsychotic treatment.
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Affiliation(s)
- Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Thiviya Selvanathan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Naren Rao
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ivonne Suridjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Pablo Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Gary Remington
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Jeffrey H Meyer
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
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Giannetti P, Politis M, Su P, Turkheimer FE, Malik O, Keihaninejad S, Wu K, Waldman A, Reynolds R, Nicholas R, Piccini P. Increased PK11195-PET binding in normal-appearing white matter in clinically isolated syndrome. ACTA ACUST UNITED AC 2014; 138:110-9. [PMID: 25416179 DOI: 10.1093/brain/awu331] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The most accurate predictor of the subsequent development of multiple sclerosis in clinically isolated syndrome is the presence of lesions at magnetic resonance imaging. We used in vivo positron emission tomography with (11)C-(R)-PK11195, a biomarker of activated microglia, to investigate the normal-appearing white matter and grey matter of subjects with clinically isolated syndrome to explore its role in the development of multiple sclerosis. Eighteen clinically isolated syndrome and eight healthy control subjects were recruited. Baseline assessment included: history, neurological examination, expanded disability status scale, magnetic resonance imaging and PK11195-positron emission tomography scans. All assessments except the PK11195-positron emission tomography scan were repeated over 2 years. SUPERPK methodology was used to measure the binding potential relative to the non-specific volume, BPND. We show a global increase of normal-appearing white matter PK11195 BPND in clinically isolated syndrome subjects compared with healthy controls (P = 0.014). Clinically isolated syndrome subjects with T2 magnetic resonance imaging lesions had higher PK11195 BPND in normal-appearing white matter (P = 0.009) and their normal-appearing white matter PK11195 BPND correlated with the Expanded Disability Status Scale (P = 0.007; r = 0.672). At 2 years those who developed dissemination in space or multiple sclerosis, had higher PK11195 BPND in normal-appearing white matter at baseline (P = 0.007 and P = 0.048, respectively). Central grey matter PK11195 BPND was increased in subjects with clinically isolated syndrome compared to healthy controls but no difference was found in cortical grey matter PK11195 BPND. Microglial activation in clinically isolated syndrome normal-appearing white matter is diffusely increased compared with healthy control subjects and is further increased in those who have magnetic resonance imaging lesions. Furthermore microglial activation in clinically isolated syndrome normal-appearing white matter is also higher in those subjects who developed multiple sclerosis at 2 years. Our finding, if replicated in a larger study, could be of prognostic value and aid early treatment decisions in clinically isolated syndrome.
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Affiliation(s)
- Paolo Giannetti
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Marios Politis
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK 2 Neurodegeneration Imaging Group, Department of Clinical Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Paul Su
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Federico E Turkheimer
- 3 Centre for Neuroimaging, Institute of Psychiatry, King's College London, De Crespigny Park, London, SE5 8AF, UK
| | - Omar Malik
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Shiva Keihaninejad
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Kit Wu
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Adam Waldman
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Richard Reynolds
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Richard Nicholas
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Paola Piccini
- 1 Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
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Zanotti-Fregonara P, Zhang Y, Jenko KJ, Gladding RL, Zoghbi SS, Fujita M, Sbardella G, Castellano S, Taliani S, Martini C, Innis RB, Da Settimo F, Pike VW. Synthesis and evaluation of translocator 18 kDa protein (TSPO) positron emission tomography (PET) radioligands with low binding sensitivity to human single nucleotide polymorphism rs6971. ACS Chem Neurosci 2014; 5:963-71. [PMID: 25123416 PMCID: PMC4210126 DOI: 10.1021/cn500138n] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
![]()
The imaging of translocator 18 kDa
protein (TSPO) in living human
brain with radioligands by positron emission tomography (PET) has
become an important means for the study of neuroinflammatory conditions
occurring in several neuropsychiatric disorders. The widely used prototypical
PET radioligand [11C](R)-PK 11195 ([11C](R)-1; [N-methyl-11C](R)-N-sec-butyl-1-(2-chlorophenyl)-N-methylisoquinoline-3-carboxamide) gives a low PET signal and is
difficult to quantify, whereas later generation radioligands have
binding sensitivity to a human single nucleotide polymorphism (SNP)
rs6971, which imposes limitations on their utility for comparative
quantitative PET studies of normal and diseased subjects. Recently,
azaisosteres of 1 have been developed with improved drug-like
properties, including enhanced TSPO affinity accompanied by moderated
lipophilicity. Here we selected three of these new ligands (7–9) for labeling with carbon-11 and for
evaluation in monkey as candidate PET radioligands for imaging brain
TSPO. Each radioligand was readily prepared by 11C-methylation
of an N-desmethyl precursor and was found to give
a high proportion of TSPO-specific binding in monkey brain. One of
these radioligands, [11C]7, the direct 4-azaisostere
of 1, presents many radioligand properties that are superior
to those reported for [11C]1, including higher
affinity, lower lipophilicity, and stable quantifiable PET signal.
Importantly, 7 was also found to show very low sensitivity
to the human SNP rs6971 in vitro. Therefore, [11C]7 now warrants evaluation in human subjects with PET to assess
its utility for imaging TSPO in human brain, irrespective of subject
genotype.
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Affiliation(s)
- Paolo Zanotti-Fregonara
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Yi Zhang
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Kimberly J. Jenko
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Robert L. Gladding
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Sami S. Zoghbi
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Masahiro Fujita
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Gianluca Sbardella
- Department
of Pharmacy, University of Salerno, 84084 Fisciano (SA), Italy
| | - Sabrina Castellano
- Department
of Pharmacy, University of Salerno, 84084 Fisciano (SA), Italy
| | - Sabrina Taliani
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Claudia Martini
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Robert B. Innis
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Federico Da Settimo
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Victor W. Pike
- Molecular
Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-0001, United States
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Amhaoul H, Staelens S, Dedeurwaerdere S. Imaging brain inflammation in epilepsy. Neuroscience 2014; 279:238-52. [DOI: 10.1016/j.neuroscience.2014.08.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/27/2014] [Accepted: 08/27/2014] [Indexed: 01/15/2023]
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Brouwer C, Jenko K, Zoghbi SS, Innis RB, Pike VW. Development of N-methyl-(2-arylquinolin-4-yl)oxypropanamides as leads to PET radioligands for translocator protein (18 kDa). J Med Chem 2014; 57:6240-51. [PMID: 24949670 PMCID: PMC4216211 DOI: 10.1021/jm5007947] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Translocator protein (18 kDa), known
as TSPO, is a recognized biomarker
of neuroinflammation. Radioligands with PET accurately quantify TSPO
in neuroinflammatory conditions. However, the existence of three human
TSPO genotypes that show differential affinity to almost all useful
TSPO PET radioligands hampers such studies. There is an unmet need
for genotype-insensitive, high-affinity, and moderately lipophilic
TSPO ligands that may serve as leads for PET radioligand development.
To address this need, we varied the known high-affinity TSPO ligand
(l)-N,N-diethyl-2-methyl-3-(2-phenylquinolin-4-yl)propanamide
in its aryl scaffold, side chain tether, and pendant substituted amido
group while retaining an N-methyl group as a site
for labeling with carbon-11. From this effort, oxygen-tethered N-methyl-aryloxypropanamides emerged as new high-affinity
TSPO ligands with attenuated lipophilicity, including one example
with attractive properties for PET radioligand development, namely N-methyl-N-phenyl-2-{[2-(pyridin-2-yl)quinolin-4-yl]oxy}propanamide
(22a; rat Ki = 0.10 nM; human
TSPO genotypes Ki = 1.4 nM; clogD = 4.18).
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Affiliation(s)
- Chad Brouwer
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
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Gu Y, Chen J, Shen J. Herbal medicines for ischemic stroke: combating inflammation as therapeutic targets. J Neuroimmune Pharmacol 2014; 9:313-39. [PMID: 24562591 DOI: 10.1007/s11481-014-9525-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/27/2014] [Indexed: 12/23/2022]
Abstract
Stroke is a debilitating disease for which limited therapeutic approaches are available currently. Thus, there is an urgent need for developing novel therapies for stroke. Astrocytes, endothelial cells and pericytes constitute a neurovascular network for metabolic requirement of neurons. During ischemic stroke, these cells contribute to post-ischemic inflammation at multiple stages of ischemic cascades. Upon ischemia onset, activated resident microglia and astrocytes, and infiltrated immune cells release multiple inflammation factors including cytokines, chemokines, enzymes, free radicals and other small molecules, not only inducing brain damage but affecting brain repair. Recent progress indicates that anti-inflammation is an important therapeutic strategy for stroke. Given a long history with direct experience in the treatment of human subjects, Traditional Chinese Medicine and its related natural compounds are recognized as important sources for drug discovery. Last decade, a great progress has been made to identify active compounds from herbal medicines with the properties of modulating post-ischemic inflammation for neuroprotection. Herein, we discuss the inflammatory pathway in early stage and secondary response to injured tissues after stroke from initial artery occlusion to brain repair, and review the active ingredients from natural products with anti-inflammation and neuroprotection effects as therapeutic agents for ischemic stroke. Further studies on the post-ischemic inflammatory mechanisms and corresponding drug candidates from herbal medicine may lead to the development of novel therapeutic strategies in stroke treatment.
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Affiliation(s)
- Yong Gu
- School of Chinese Medicine, LKS Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong, SAR, China
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Giannetti P, Politis M, Su P, Turkheimer F, Malik O, Keihaninejad S, Wu K, Reynolds R, Nicholas R, Piccini P. Microglia activation in multiple sclerosis black holes predicts outcome in progressive patients: an in vivo [(11)C](R)-PK11195-PET pilot study. Neurobiol Dis 2014; 65:203-10. [PMID: 24508617 DOI: 10.1016/j.nbd.2014.01.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 01/08/2014] [Accepted: 01/30/2014] [Indexed: 10/25/2022] Open
Abstract
The pathophysiological correlates and the contribution to persisting disability of hypointense T1-weighted MRI lesions, black holes (BH), in multiple sclerosis (MS) are still unclear. In order to study the in vivo functional correlates of this MRI finding, we used 11C-PK11195 PET (PK-PET) to investigate changes in microglial activity. Ten relapsing and 9 progressive MS subjects had a PK-PET scan and a MRI scan alongside a full clinical assessment, including the expanded disability status scale (EDSS) for evaluation of disability. We studied the PK binding potential of the specifically bound radioligand relative to the non-displaceable radioligand in tissue (BPND) in T1 BHs. Out of a total of 1242 BHs identified, 947 were PK enhancing. The PKBPND was correlated with the EDSS (r=0.818; p<0.05) only in the progressive group. In the relapsing patients there was an inverse correlation between PKBPND and BH total lesion volume in whole brain (r=-0.781; p<0.05). When progressive patients were grouped according to the disability outcome at 2years from the PK-PET scan, the total PKBPND in BHs was found to be a significant outcome predictor of disability (p<0.01). Our findings show that relapsing and progressive patients have heterogeneous patterns of PKBPND in T1 BHs and indicate that BHs are not just "holes" representing loss of axons and myelin, but display inflammatory activity in the form of activated microglia. The significant association between PKBPND, neurological impairment and outcome in progressive subjects supports a role for activated microglia in disability progression.
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Affiliation(s)
- Paolo Giannetti
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Marios Politis
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK; Neurodegeneration Imaging Group, Department of Clinical Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.
| | - Paul Su
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Federico Turkheimer
- Centre for Neuroimaging, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK.
| | - Omar Malik
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Shiva Keihaninejad
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Kit Wu
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Richard Reynolds
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Richard Nicholas
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
| | - Paola Piccini
- Centre for Neuroinflammation and Neurodegeneration, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
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Denora N, Laquintana V, Lopalco A, Iacobazzi RM, Lopedota A, Cutrignelli A, Iacobellis G, Annese C, Cascione M, Leporatti S, Franco M. In vitro targeting and imaging the translocator protein TSPO 18-kDa through G(4)-PAMAM–FITC labeled dendrimer. J Control Release 2013; 172:1111-25. [DOI: 10.1016/j.jconrel.2013.09.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/15/2013] [Accepted: 09/18/2013] [Indexed: 01/25/2023]
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Trapani A, Palazzo C, de Candia M, Lasorsa FM, Trapani G. Targeting of the Translocator Protein 18 kDa (TSPO): A Valuable Approach for Nuclear and Optical Imaging of Activated Microglia. Bioconjug Chem 2013; 24:1415-28. [DOI: 10.1021/bc300666f] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Adriana Trapani
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | - Claudio Palazzo
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | - Modesto de Candia
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | | | - Giuseppe Trapani
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
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Wu C, Li F, Niu G, Chen X. PET imaging of inflammation biomarkers. Theranostics 2013; 3:448-66. [PMID: 23843893 PMCID: PMC3706689 DOI: 10.7150/thno.6592] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 05/24/2013] [Indexed: 01/04/2023] Open
Abstract
Inflammation plays a significant role in many disease processes. Development in molecular imaging in recent years provides new insight into the diagnosis and treatment evaluation of various inflammatory diseases and diseases involving inflammatory process. Positron emission tomography using (18)F-FDG has been successfully applied in clinical oncology and neurology and in the inflammation realm. In addition to glucose metabolism, a variety of targets for inflammation imaging are being discovered and utilized, some of which are considered superior to FDG for imaging inflammation. This review summarizes the potential inflammation imaging targets and corresponding PET tracers, and the applications of PET in major inflammatory diseases and tumor associated inflammation. Also, the current attempt in differentiating inflammation from tumor using PET is also discussed.
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Miller AH, Haroon E, Raison CL, Felger JC. Cytokine targets in the brain: impact on neurotransmitters and neurocircuits. Depress Anxiety 2013; 30:297-306. [PMID: 23468190 PMCID: PMC4141874 DOI: 10.1002/da.22084] [Citation(s) in RCA: 519] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/26/2013] [Accepted: 01/31/2013] [Indexed: 01/18/2023] Open
Abstract
Increasing attention has been paid to the role of inflammation in a host of illnesses including neuropsychiatric disorders such as depression and anxiety. Activation of the inflammatory response leads to release of inflammatory cytokines and mobilization of immune cells both of which have been shown to access the brain and alter behavior. The mechanisms of the effects of inflammation on the brain have become an area of intensive study. Data indicate that cytokines and their signaling pathways including p38 mitogen-activated protein kinase have significant effects on the metabolism of multiple neurotransmitters such as serotonin, dopamine, and glutamate through impact on their synthesis, release, and reuptake. Cytokines also activate the kynurenine pathway, which not only depletes tryptophan, the primary amino acid precursor of serotonin, but also generates neuroactive metabolites that can significantly influence the regulation of dopamine and glutamate. Through their effects on neurotransmitter systems, cytokines impact neurocircuits in the brain including the basal ganglia and anterior cingulate cortex, leading to significant changes in motor activity and motivation as well as anxiety, arousal, and alarm. In the context of environmental challenge from the microbial world, these effects of inflammatory cytokines on the brain represent an orchestrated suite of behavioral and immune responses that subserve evolutionary priorities to shunt metabolic resources away from environmental exploration to fighting infection and wound healing, while also maintaining vigilance against attack, injury, and further pathogen exposure. Chronic activation of this innate behavioral and immune response may lead to depression and anxiety disorders in vulnerable individuals.
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Affiliation(s)
- Andrew H. Miller
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA
| | - Ebrahim Haroon
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA
| | - Charles L. Raison
- Department of Psychiatry and Behavioral Sciences, University of Arizona School of Medicine, Tuscon, AZ
| | - Jennifer C. Felger
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA
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Affiliation(s)
- Dave C. Anderson
- Center for Advanced Drug Research; SRI International; 140 Research Drive; Harrisonburg; Virginia; 22802; USA
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Zhang X, Paule MG, Wang C, Slikker W. Application of microPET imaging approaches in the study of pediatric anesthetic-induced neuronal toxicity. J Appl Toxicol 2013; 33:861-8. [DOI: 10.1002/jat.2857] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 12/14/2022]
Affiliation(s)
- Xuan Zhang
- Division of Neurotoxicology; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
| | - Merle G. Paule
- Division of Neurotoxicology; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
| | - Cheng Wang
- Division of Neurotoxicology; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
| | - William Slikker
- Office of the Director; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
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Abstract
Microglia are resident immune cells in the brain and spinal cord. These cells provide immune surveillance and are mobilized in response to disparate diseases and injuries. Although microglial activation is often considered neurotoxic, microglia are essential defenders against many neurodegenerative diseases. It also seems increasingly likely that microglial dysfunction can underlie certain neurological diseases without an obvious immune component.
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Affiliation(s)
- Adriano Aguzzi
- Institute of Neuropathology, University Hospital Zurich, Schmelzbergstrasse 12, CH-8012 Zurich, Switzerland.
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Zhang X, Paule MG, Newport GD, Liu F, Callicott R, Liu S, Berridge MS, Apana SM, Slikker W, Wang C. MicroPET/CT Imaging of [18F]-FEPPA in the Nonhuman Primate: A Potential Biomarker of Pathogenic Processes Associated with Anesthetic-Induced Neurotoxicity. ACTA ACUST UNITED AC 2012. [DOI: 10.5402/2012/261640] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Background. The inhalation anesthetics nitrous oxide (N2O) and isoflurane (ISO) are used in surgical procedures for human infants. Injury to the central nervous system is often accompanied by localization of activated microglia or astrocytosis at the site of injury. The tracer that targets to the peripheral benzodiazepine receptor (PBR), [18F]N-2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]-FEPPA), has been reported as a sensitive biomarker for the detection of neuronal damage/inflammation. Methods. On postnatal day (PND) 5 or 6 rhesus monkey neonates were exposed to a mixture of N2O/oxygen and ISO for 8 hours and control monkeys were exposed to room air. MicroPET/CT images with [18F]-FEPPA were obtained for each monkey 1 day, one week, three weeks, and 6 months after the anesthetic exposure. Results. The radiotracer quickly distributed into the brains of both treated and control monkeys on all scan days. One day after anesthetic exposure, the uptake of [18F]-FEPPA was significantly increased in the temporal lobe. One week after exposure, the uptake of [18F]-FEPPA in the frontal lobe of treated animals was significantly greater than that in controls. Conclusions. These findings suggest that microPET imaging is capable of dynamic detection of inhaled anesthetic-induced brain damage in different brain regions of the nonhuman primate.
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Affiliation(s)
- Xuan Zhang
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Merle G. Paule
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Glenn D. Newport
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Fang Liu
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Ralph Callicott
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Shuliang Liu
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Marc S. Berridge
- 3D Imaging, LLC, Little Rock, AR 72113, USA
- University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Scott M. Apana
- 3D Imaging, LLC, Little Rock, AR 72113, USA
- University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - William Slikker
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
| | - Cheng Wang
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
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Design, synthesis and structure–activity relationships of novel benzoxazolone derivatives as 18kDa translocator protein (TSPO) ligands. Bioorg Med Chem 2012; 20:5568-82. [DOI: 10.1016/j.bmc.2012.07.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 07/13/2012] [Accepted: 07/13/2012] [Indexed: 11/18/2022]
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Zimmer L, Luxen A. PET radiotracers for molecular imaging in the brain: Past, present and future. Neuroimage 2012; 61:363-70. [DOI: 10.1016/j.neuroimage.2011.12.037] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/15/2011] [Indexed: 12/22/2022] Open
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