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Kikuchi T, Okamura T, Zhang MR. Efficient Reductive N- 11C-Methylation Using Arylamines or Alkylamines and In Situ-Generated [ 11C]Formaldehyde From [ 11C]Methyl Iodide. J Labelled Comp Radiopharm 2024; 67:254-262. [PMID: 38703027 DOI: 10.1002/jlcr.4095] [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: 12/25/2023] [Revised: 03/05/2024] [Accepted: 04/13/2024] [Indexed: 05/06/2024]
Abstract
Reductive N-11C-methylation using [11C]formaldehyde and amines has been used to prepare N-11C-methylated compounds. However, the yields of the N-11C-methylated compounds are often insufficient. In this study, we developed an efficient method for base-free reductive N-11C-methylation that is applicable to a wide variety of substrates, including arylamines bearing electron-withdrawing and electron-donating substituents. A 2-picoline borane complex, which is a stable and mild reductant, was used. Dimethyl sulfoxide was used as the primary reaction solvent, and glacial acetic acid or aqueous acetic acid was used as a cosolvent. While reductive N-11C-methylation efficiently proceeded under anhydrous conditions in most cases, the addition of water to the reductive N-11C-methylation generally increased the yield of the N-11C-methylated compounds. Substrates with hydroxy, carboxyl, nitrile, nitro, ester, amide, and phenone moieties and amine salts were applicable to the reaction. This proposed method for reductive N-11C-methylation should be applicable to a wide variety of substrates, including thermo-labile and base-sensitive compounds because the reaction was performed under relatively mild conditions (70°C) without the need for a base.
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Affiliation(s)
- Tatsuya Kikuchi
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Toshimitsu Okamura
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
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2
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Brier MR, Taha F. Measuring Pathology in Patients with Multiple Sclerosis Using Positron Emission Tomography. Curr Neurol Neurosci Rep 2023; 23:479-488. [PMID: 37418219 DOI: 10.1007/s11910-023-01285-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2023] [Indexed: 07/08/2023]
Abstract
PURPOSE OF REVIEW Multiple sclerosis is characterized by a diverse and complex pathology. Clinical relapses, the hallmark of the disease, are accompanied by focal white matter lesions with intense inflammatory and demyelinating activity. Prevention of these relapses has been the major focus of pharmaceutical development, and it is now possible to dramatically reduce this inflammatory activity. Unfortunately, disability accumulation persists for many people living with multiple sclerosis owing to ongoing damage within existing lesions, pathology outside of discrete lesions, and other yet unknown factors. Understanding this complex pathological cascade will be critical to stopping progressive multiple sclerosis. Positron emission tomography uses biochemically specific radioligands to quantitatively measure pathological processes with molecular specificity. This review examines recent advances in the understanding of multiple sclerosis facilitated by positron emission tomography and identifies future avenues to expand understanding and treatment options. RECENT FINDINGS An increasing number of radiotracers allow for the quantitative measurement of inflammatory abnormalities, de- and re-myelination, and metabolic disruption associated with multiple sclerosis. The studies have identified contributions of ongoing, smoldering inflammation to accumulating tissue injury and clinical worsening. Myelin studies have quantified the dynamics of myelin loss and recovery. Lastly, metabolic changes have been found to contribute to symptom worsening. The molecular specificity facilitated by positron emission tomography in people living with multiple sclerosis will critically inform efforts to modulate the pathology leading to progressive disability accumulation. Existing studies show the power of this approach applied to multiple sclerosis. This armamentarium of radioligands allows for new understanding of how the brain and spinal cord of people is impacted by multiple sclerosis.
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Affiliation(s)
- Matthew R Brier
- Department of Neurology, John L Trotter MS Center, Washington University in St. Louis, St. Louis, USA.
| | - Farris Taha
- Department of Neurology, Medical University of South Carolina, Charleston, USA
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3
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Wei B, Weng N, Fu L, Li Y, Wang X, Yin R, Jiang T. Synthesis and bioactivity evaluation of a myelin-specific contrast agent for magnetic resonance imaging of myelination in central nervous system. Bioorg Med Chem 2023; 84:117257. [PMID: 37001243 DOI: 10.1016/j.bmc.2023.117257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/01/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023]
Abstract
Demyelination exists in many neurological diseases of nervous system, such as stroke. Currently, magnetic resonance imaging (MRI) has been the main tool for diagnosing and monitoring the myelin related diseases. However, the conventional MRI unable to distinguish demyelinating lesions from other inflammatory lesions. To address this problem, we have designed and prepared a myelin specific magnetic resonance contrast agent, Gd-DTDAS, which was based myelin specific moiety MeDASg and Gd-DTPAh. In this work, we verified the specificity and sensitivity of Gd-DTDAS to myelin. Moreover, we investigated the specific binding ability of Gd-DTDAS to myelin sheath in the MCAO micei models. The in vivo imaging results showed that Gd-DTDAS can bind to the undamaged myelin sheath in the BBB disruption areas, and in turn reduce the relaxation time. The fluorescence images also showed significant fluorescence in the brain right infarct area of the MCAO model mice with administration of Gd-DTDAS. The above results confirmed that Gd-DTDAS could be preferentially distributed in areas with high myelination and can detect focally induced demyelination.
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Affiliation(s)
- Bin Wei
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Na Weng
- Department of Nuclear Medicine, Binzhou Medical University Hospital, Binzhou, Shandong 256603, China
| | - Lei Fu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Yuxuan Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Xu Wang
- Department of Nuclear Medicine, Binzhou Medical University Hospital, Binzhou, Shandong 256603, China.
| | - Ruijuan Yin
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Marine Biomedical Research Institute of Qiangdao, Ocean University of China, Qingdao, 266237, China.
| | - Tao Jiang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
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4
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van der Weijden CWJ, van der Hoorn A, Wang Y, Willemsen ATM, Dierckx RAJO, Lammertsma AA, de Vries EFJ. Investigation of image-derived input functions for non-invasive quantification of myelin density using [ 11C]MeDAS PET. Neuroimage 2022; 264:119772. [PMID: 36436711 DOI: 10.1016/j.neuroimage.2022.119772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease. Current treatments are focussed on immune suppression to modulate pathogenic activity that causes myelin damage. New treatment strategies are needed to prevent demyelination and promote remyelination. Development of such myelin repair therapies require a sensitive and specific biomarker for efficacy evaluation. Recently, it has been shown that quantification of myelin density is possible using [11C]MeDAS PET. This method, however, requires arterial blood sampling to generate an arterial input function (AIF). As the invasive nature of arterial sampling will reduce clinical applicability, the purpose of this study was to assess whether an image-derived input function (IDIF) can be used as an alternative way to facilitate its routine clinical use. Six healthy controls and 11 MS patients underwent MRI and [11C]MeDAS PET with arterial blood sampling. The application of both population-based whole blood-to-plasma conversion and metabolite corrections were assessed for the AIF. Next, summed images of the early time frames (0-70 s) and the frame with the highest blood-brain contrast were used to generate IDIFs. IDIFs were created using either the hottest 2, 4, 6 or 12 voxels, or an isocontour of the hottest 10% voxels of the carotid artery. This was followed by blood-to-plasma conversion and metabolite correction of the IDIF. The application of a population-based metabolite correction of the AIF resulted in high correlations of tracer binding (Ki) within subjects, but variable bias across subjects. All IDIFs had a sharper and higher peak in the blood curves than the AIF, most likely due to dispersion during blood sampling. All IDIF methods resulted in similar high correlations within subjects (r = 0.95-0.98), but highly variable bias across subjects (mean slope=0.90-1.09). Therefore, both the use of population based blood-plasma and metabolite corrections and the generation of the image-derived whole-blood curve resulted in substantial bias in [11C]MeDAS PET quantification, due to high inter-subject variability. Consequently, when unbiased quantification of [11C]MeDAS PET data is required, individual AIF needs to be used.
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Affiliation(s)
- Chris W J van der Weijden
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Anouk van der Hoorn
- Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Yanming Wang
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Antoon T M Willemsen
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Rudi A J O Dierckx
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Adriaan A Lammertsma
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Erik F J de Vries
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands.
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5
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Shaghaghi M, Cai K. Toward In Vivo MRI of the Tissue Proton Exchange Rate in Humans. BIOSENSORS 2022; 12:bios12100815. [PMID: 36290953 PMCID: PMC9599426 DOI: 10.3390/bios12100815] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/19/2022] [Accepted: 09/29/2022] [Indexed: 05/28/2023]
Abstract
Quantification of proton exchange rate (kex) is a challenge in MR studies. Current techniques either have low resolutions or are dependent on the estimation of parameters that are not measurable. The Omega plot method, on the other hand, provides a direct way for determining kex independent of the agent concentration. However, it cannot be used for in vivo studies without some modification due to the contributions from the water signal. In vivo tissue proton exchange rate (kex) MRI, based on the direct saturation (DS) removed Omega plot, quantifies the weighted average of kex of the endogenous tissue metabolites. This technique has been successfully employed for imaging the variation in the kex of ex vivo phantoms, as well as in vivo human brains in healthy subjects, and stroke or multiple sclerosis (MS) patients. In this paper, we present a brief review of the methods used for kex imaging with a focus on the development of in vivo kex MRI technique based on the DS-removed Omega plot. We then review the recent clinical studies utilizing this technique for better characterizing brain lesions. We also outline technical challenges for the presented technique and discuss its prospects for detecting tissue microenvironmental changes under oxidative stress.
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Affiliation(s)
- Mehran Shaghaghi
- Department of Radiology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Kejia Cai
- Department of Radiology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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6
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Zeydan B, Schwarz CG, Przybelski SA, Lesnick TG, Kremers WK, Senjem ML, Kantarci OH, Min PH, Kemp BJ, Jack CR, Kantarci K, Lowe VJ. Comparison of 11C-Pittsburgh Compound B and 18F-Flutemetamol White Matter Binding in PET. J Nucl Med 2022; 63:1239-1244. [PMID: 34916245 PMCID: PMC9364341 DOI: 10.2967/jnumed.121.263281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/30/2021] [Indexed: 02/03/2023] Open
Abstract
PET imaging with β-amyloid ligands is emerging as a molecular imaging technique targeting white matter integrity and demyelination. β-amyloid PET ligands such as 11C-Pittsburgh compound B (11C-PiB) have been considered for quantitative measurement of myelin content changes in multiple sclerosis, but 11C-PiB is not commercially available given its short half-life. A 18F PET ligand such as flutemetamol with a longer half-life may be an alternative, but its ability to differentiate white matter hyperintensities (WMH) from normal-appearing white matter (NAWM) and its relationship with age remains to be investigated. Methods: Cognitively unimpaired (CU) older and younger adults (n = 61) were recruited from the community responding to a study advertisement for β-amyloid PET. Participants prospectively underwent MRI, 11C-PiB, and 18F-flutemetamol PET scans. MRI fluid-attenuated inversion recovery images were segmented into WMH and NAWM and registered to the T1-weighted MRI. 11C-PiB and 18F-flutemetamol PET images were also registered to the T1-weighted MRI. 11C-PiB and 18F-flutemetamol SUV ratios (SUVrs) from the WMH and NAWM were calculated using cerebellar crus uptake as a reference for both 11C-PiB and 18F-flutemetamol. Results: The median age was 38 y (range, 30-48 y) in younger adults and 67 y (range, 61-83 y) in older adults. WMH and NAWM SUVrs were higher with 18F-flutemetamol than with 11C-PiB in both older (P < 0.001) and younger (P < 0.001) CU adults. 11C-PiB and 18F-flutemetamol SUVrs were higher in older than in younger CU adults in both WMH (P < 0.001) and NAWM (P < 0.001). 11C-PiB and 18F-flutemetamol SUVrs were higher in NAWM than WMH in both older (P < 0.001) and younger (P < 0.001) CU adults. There was no apparent difference between 11C-PiB and 18F-flutemetamol SUVrs in differentiating WMH from NAWM in older and in younger adults. Conclusion:11C-PiB and 18F-flutemetamol show a similar topographic pattern of uptake in white matter with a similar association with age in WMH and NAWM. 11C-PiB and 18F-flutemetamol can also effectively distinguish between WMH and NAWM. However, given its longer half-life, commercial availability, and higher binding potential, 18F-flutemetamol can be an alternative to 11C-PiB in molecular imaging studies specifically targeting multiple sclerosis to evaluate white matter integrity.
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Affiliation(s)
- Burcu Zeydan
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | | | - Scott A Przybelski
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; and
| | - Timothy G Lesnick
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; and
| | - Walter K Kremers
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; and
| | - Matthew L Senjem
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
- Department of Information Technology, Mayo Clinic, Rochester, Minnesota
| | | | - Paul H Min
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Bradley J Kemp
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | | | - Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Val J Lowe
- Department of Radiology, Mayo Clinic, Rochester, Minnesota;
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7
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van der Weijden CWJ, Meilof JF, van der Hoorn A, Zhu J, Wu C, Wang Y, Willemsen ATM, Dierckx RAJO, Lammertsma AA, de Vries EFJ. Quantitative assessment of myelin density using [ 11C]MeDAS PET in patients with multiple sclerosis: a first-in-human study. Eur J Nucl Med Mol Imaging 2022; 49:3492-3507. [PMID: 35366079 PMCID: PMC9308583 DOI: 10.1007/s00259-022-05770-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/19/2022] [Indexed: 12/21/2022]
Abstract
Purpose Multiple sclerosis (MS) is a disease characterized by inflammatory demyelinated lesions. New treatment strategies are being developed to stimulate myelin repair. Quantitative myelin imaging could facilitate these developments. This first-in-man study aimed to evaluate [11C]MeDAS as a PET tracer for myelin imaging in humans. Methods Six healthy controls and 11 MS patients underwent MRI and dynamic [11C]MeDAS PET scanning with arterial sampling. Lesion detection and classification were performed on MRI. [11C]MeDAS time-activity curves of brain regions and MS lesions were fitted with various compartment models for the identification of the best model to describe [11C]MeDAS kinetics. Several simplified methods were compared to the optimal compartment model. Results Visual analysis of the fits of [11C]MeDAS time-activity curves showed no preference for irreversible (2T3k) or reversible (2T4k) two-tissue compartment model. Both volume of distribution and binding potential estimates showed a high degree of variability. As this was not the case for 2T3k-derived net influx rate (Ki), the 2T3k model was selected as the model of choice. Simplified methods, such as SUV and MLAIR2 correlated well with 2T3k-derived Ki, but SUV showed subject-dependent bias when compared to 2T3k. Both the 2T3k model and the simplified methods were able to differentiate not only between gray and white matter, but also between lesions with different myelin densities. Conclusion [11C]MeDAS PET can be used for quantification of myelin density in MS patients and is able to distinguish differences in myelin density within MS lesions. The 2T3k model is the optimal compartment model and MLAIR2 is the best simplified method for quantification. Trial registration. NL7262. Registered 18 September 2018. Supplementary information The online version contains supplementary material available at 10.1007/s00259-022-05770-4.
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Affiliation(s)
- Chris W J van der Weijden
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Jan F Meilof
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
- Department of Neurology, Martini Ziekenhuis, Groningen, The Netherlands
| | - Anouk van der Hoorn
- Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Junqing Zhu
- Department of Radiology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Chunying Wu
- Department of Radiology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yanming Wang
- Department of Radiology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Antoon T M Willemsen
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Adriaan A Lammertsma
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Erik F J de Vries
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands.
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8
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Van Camp N, Lavisse S, Roost P, Gubinelli F, Hillmer A, Boutin H. TSPO imaging in animal models of brain diseases. Eur J Nucl Med Mol Imaging 2021; 49:77-109. [PMID: 34245328 PMCID: PMC8712305 DOI: 10.1007/s00259-021-05379-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/25/2021] [Indexed: 12/19/2022]
Abstract
Over the last 30 years, the 18-kDa TSPO protein has been considered as the PET imaging biomarker of reference to measure increased neuroinflammation. Generally assumed to image activated microglia, TSPO has also been detected in endothelial cells and activated astrocytes. Here, we provide an exhaustive overview of the recent literature on the TSPO-PET imaging (i) in the search and development of new TSPO tracers and (ii) in the understanding of acute and chronic neuroinflammation in animal models of neurological disorders. Generally, studies testing new TSPO radiotracers against the prototypic [11C]-R-PK11195 or more recent competitors use models of acute focal neuroinflammation (e.g. stroke or lipopolysaccharide injection). These studies have led to the development of over 60 new tracers during the last 15 years. These studies highlighted that interpretation of TSPO-PET is easier in acute models of focal lesions, whereas in chronic models with lower or diffuse microglial activation, such as models of Alzheimer's disease or Parkinson's disease, TSPO quantification for detection of neuroinflammation is more challenging, mirroring what is observed in clinic. Moreover, technical limitations of preclinical scanners provide a drawback when studying modest neuroinflammation in small brains (e.g. in mice). Overall, this review underlines the value of TSPO imaging to study the time course or response to treatment of neuroinflammation in acute or chronic models of diseases. As such, TSPO remains the gold standard biomarker reference for neuroinflammation, waiting for new radioligands for other, more specific targets for neuroinflammatory processes and/or immune cells to emerge.
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Affiliation(s)
- Nadja Van Camp
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Sonia Lavisse
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Pauline Roost
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Francesco Gubinelli
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Ansel Hillmer
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
- Department of Radiology & Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale School of Engineering & Applied Science, New Haven, CT, USA
| | - Hervé Boutin
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Brain and Mental Health, University of Manchester, M13 9PL, Manchester, UK.
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, M20 3LJ, Manchester, UK.
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK.
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9
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Positron emission tomography in multiple sclerosis - straight to the target. Nat Rev Neurol 2021; 17:663-675. [PMID: 34545219 DOI: 10.1038/s41582-021-00537-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2021] [Indexed: 02/08/2023]
Abstract
Following the impressive progress in the treatment of relapsing-remitting multiple sclerosis (MS), the major challenge ahead is the development of treatments to prevent or delay the irreversible accumulation of clinical disability in progressive forms of the disease. The substrate of clinical progression is neuro-axonal degeneration, and a deep understanding of the mechanisms that underlie this process is a precondition for the development of therapies for progressive MS. PET imaging involves the use of radiolabelled compounds that bind to specific cellular and metabolic targets, thereby enabling direct in vivo measurement of several pathological processes. This approach can provide key insights into the clinical relevance of these processes and their chronological sequence during the disease course. In this Review, we focus on the contribution that PET is making to our understanding of extraneuronal and intraneuronal mechanisms that are involved in the pathogenesis of irreversible neuro-axonal damage in MS. We consider the major challenges with the use of PET in MS and the steps necessary to realize clinical benefits of the technique. In addition, we discuss the potential of emerging PET tracers and future applications of existing compounds to facilitate the identification of effective neuroprotective treatments for patients with MS.
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10
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Guehl NJ, Ramos-Torres KM, Linnman C, Moon SH, Dhaynaut M, Wilks MQ, Han PK, Ma C, Neelamegam R, Zhou YP, Popko B, Correia JA, Reich DS, Fakhri GE, Herscovitch P, Normandin MD, Brugarolas P. Evaluation of the potassium channel tracer [ 18F]3F4AP in rhesus macaques. J Cereb Blood Flow Metab 2021; 41:1721-1733. [PMID: 33090071 PMCID: PMC8221756 DOI: 10.1177/0271678x20963404] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Demyelination causes slowed or failed neuronal conduction and is a driver of disability in multiple sclerosis and other neurological diseases. Currently, the gold standard for imaging demyelination is MRI, but despite its high spatial resolution and sensitivity to demyelinated lesions, it remains challenging to obtain specific and quantitative measures of molecular changes involved in demyelination. To understand the contribution of demyelination in different diseases and to assess the efficacy of myelin-repair therapies, it is critical to develop new in vivo imaging tools sensitive to changes induced by demyelination. Upon demyelination, axonal K+ channels, normally located underneath the myelin sheath, become exposed and increase in expression, causing impaired conduction. Here, we investigate the properties of the K+ channel PET tracer [18F]3F4AP in primates and its sensitivity to a focal brain injury that occurred three years prior to imaging. [18F]3F4AP exhibited favorable properties for brain imaging including high brain penetration, high metabolic stability, high plasma availability, high reproducibility, high specificity, and fast kinetics. [18F]3F4AP showed preferential binding in areas of low myelin content as well as in the previously injured area. Sensitivity of [18F]3F4AP for the focal brain injury was higher than [18F]FDG, [11C]PiB, and [11C]PBR28, and compared favorably to currently used MRI methods.
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Affiliation(s)
- Nicolas J Guehl
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Karla M Ramos-Torres
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Clas Linnman
- Spaulding Neuroimaging Lab, Spaulding Rehabilitation Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Sung-Hyun Moon
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Maeva Dhaynaut
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Moses Q Wilks
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Paul K Han
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Chao Ma
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Ramesh Neelamegam
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Brian Popko
- Department of Neurology, Northwestern Feinberg School of Medicine, Chicago, IL, USA
| | - John A Correia
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Peter Herscovitch
- Positron Emission Tomography Department, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Marc D Normandin
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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11
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van der Weijden CWJ, García DV, Borra RJH, Thurner P, Meilof JF, van Laar PJ, Dierckx RAJO, Gutmann IW, de Vries EFJ. Myelin quantification with MRI: A systematic review of accuracy and reproducibility. Neuroimage 2020; 226:117561. [PMID: 33189927 DOI: 10.1016/j.neuroimage.2020.117561] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/27/2020] [Accepted: 11/07/2020] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES Currently, multiple sclerosis is treated with anti-inflammatory therapies, but these treatments lack efficacy in progressive disease. New treatment strategies aim to repair myelin damage and efficacy evaluation of such new therapies would benefit from validated myelin imaging techniques. Several MRI methods for quantification of myelin density are available now. This systematic review aims to analyse the performance of these MRI methods. METHODS Studies comparing myelin quantification by MRI with histology, the current gold standard, or assessing reproducibility were retrieved from PubMed/MEDLINE and Embase (until December 2019). Included studies assessed both myelin histology and MRI quantitatively. Correlation or variance measurements were extracted from the studies. Non-parametric tests were used to analyse differences in study methodologies. RESULTS The search yielded 1348 unique articles. Twenty-two animal studies and 13 human studies correlated myelin MRI with histology. Eighteen clinical studies analysed the reproducibility. Overall bias risk was low or unclear. All MRI methods performed comparably, with a mean correlation between MRI and histology of R2=0.54 (SD=0.30) for animal studies, and R2=0.54 (SD=0.18) for human studies. Reproducibility for the MRI methods was good (ICC=0.75-0.93, R2=0.90-0.98, COV=1.3-27%), except for MTR (ICC=0.05-0.51). CONCLUSIONS Overall, MRI-based myelin imaging methods show a fairly good correlation with histology and a good reproducibility. However, the amount of validation data is too limited and the variability in performance between studies is too large to select the optimal MRI method for myelin quantification yet.
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Affiliation(s)
- Chris W J van der Weijden
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - David Vállez García
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Ronald J H Borra
- Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Patrick Thurner
- Universitätsklinik für Radiologie und Nuklearmedizin, Medizinische Universität Wien, Währinger Gürtel 18-20, 1090 Wien, Austria.
| | - Jan F Meilof
- Multiple Sclerosis Center Noord Nederland, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Peter-Jan van Laar
- Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, Zorggroep Twente, Zilvermeeuw 1, 7609 PP Almelo, the Netherlands.
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
| | - Ingomar W Gutmann
- Physics of Functional Material, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands.
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12
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Watanabe H, Sakai S, Iikuni S, Shimizu Y, Shirakawa H, Kaneko S, Ono M. Synthesis and biological evaluation of radioiodinated 3-phenylcoumarin derivatives targeting myelin in multiple sclerosis. Bioorg Med Chem Lett 2020; 30:127562. [PMID: 32971260 DOI: 10.1016/j.bmcl.2020.127562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 02/06/2023]
Abstract
Myelin is a lipid multilayer involved in the rate of nerve transmission, and its loss is a pathological feature of multiple sclerosis in brains. Since in vivo imaging of myelin may be useful for drug development, early diagnosis, and monitoring the disease stage, we designed, synthesized, and evaluated eight novel radioiodinated 3-phenylcoumarin derivatives as imaging probes targeting myelin. In the biodistribution study using normal mice, all compounds displayed sufficient brain uptake, ranging from 2.5 to 5.0% ID/g, at 2 min postinjection. On ex vivo autoradiography, [125I]18 and [125I]21, which have a dimethylamino group, showed high binding affinity for myelin in the normal mouse brain. In addition, the radioactivity accumulation of [125I]21 in the white matter of the spinal cord in the experimental autoimmune encephalomyelitis mice was lower than that in naive mice. These results suggest that [123I]21 shows potential as a single photon emission computed tomography probe targeting myelin.
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Affiliation(s)
- Hiroyuki Watanabe
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Shiori Sakai
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shimpei Iikuni
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoichi Shimizu
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan; Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Hisashi Shirakawa
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shuji Kaneko
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masahiro Ono
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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13
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Parente A, Maciel ES, J O Dierckx RA, Langendijk JA, de Vries EFJ, Doorduin J. Delayed effects of a single-dose whole-brain radiation therapy on glucose metabolism and myelin density: a longitudinal PET study. Int J Radiat Biol 2020; 96:1135-1143. [PMID: 32602390 DOI: 10.1080/09553002.2020.1787542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE Radiotherapy is an important treatment option for brain tumors, but the unavoidable irradiation of normal brain tissue can lead to delayed cognitive impairment. The mechanisms involved are still not well explained and, therefore, new tools to investigate the processes leading to the delayed symptoms of brain irradiation are warranted. In this study, positron emission tomography (PET) is used to explore delayed functional changes induced by brain irradiation. MATERIALS AND METHODS Male Wistar rats were subjected to a single 25-Gy dose of whole brain X-ray irradiation, or sham-irradiation. To investigate delayed effects of radiation on cerebral glucose metabolism and myelin density, 18F-fluorodeoxyglucose (18F-FDG) PET scans were performed at baseline and on day 64 and 94, whereas N-11C-methyl-4,4'-diaminostilbene (11C-MeDAS) PET scans were performed at baseline and on day 60 and 90 post-irradiation. In addition, the open field test (OFT) and novel spatial recognition (NSR) test were performed at baseline and on days 59 and 89 to investigate whether whole brain irradiation induces behavioral changes. RESULTS Whole-brain irradiation caused loss of bodyweight and delayed cerebral hypometabolism, with 18F-FDG uptake in all brain regions being significantly decreased in irradiated rat on day 64 while it remained unchanged in control animals. Only amygdala and cortical brain regions of irradiated rats still showed reduced 18F-FDG uptake on day 94. 11C-MeDAS uptake in control animals was significantly lower on days 60 and 90 than at the baseline, suggesting a reduction in myelin density in young adults. In irradiated animals, 11C-MeDAS uptake was similarly reduced on day 60, but on day 90 tracer uptake was somewhat increased and not significantly different from baseline anymore. Behavioral tests showed a similar pattern in control and irradiated animals. In both groups, the OFT showed significantly reduced mobility on days 59 and 89, whereas the NSR did not reveal any significant changes in spatial memory over time. Interestingly, a positive correlation between the NSR and 11C-MeDAS uptake was observed in irradiated rats. CONCLUSIONS Whole-brain irradiation causes delayed brain hypometabolism, which is not accompanied by white matter loss. Irradiated animals showed similar behavioral changes over time as control animals and, therefore, cerebral hypometabolism could not be linked to behavioral abnormalities. However, spatial memory seems to be associated with myelin density in irradiated rats.
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Affiliation(s)
- Andrea Parente
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Elisa Scandiuzzi Maciel
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Johannes A Langendijk
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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14
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de Paula Faria D. Myelin positron emission tomography (PET) imaging in multiple sclerosis. Neural Regen Res 2020; 15:1842-1843. [PMID: 32246627 PMCID: PMC7513961 DOI: 10.4103/1673-5374.280311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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15
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Auvity S, Tonietto M, Caillé F, Bodini B, Bottlaender M, Tournier N, Kuhnast B, Stankoff B. Repurposing radiotracers for myelin imaging: a study comparing 18F-florbetaben, 18F-florbetapir, 18F-flutemetamol,11C-MeDAS, and 11C-PiB. Eur J Nucl Med Mol Imaging 2019; 47:490-501. [PMID: 31686177 DOI: 10.1007/s00259-019-04516-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 08/29/2019] [Indexed: 12/25/2022]
Abstract
PURPOSE Drugs promoting myelin repair represent a promising therapeutic approach in multiple sclerosis and several candidate molecules are currently being evaluated, fostering the need of a quantitative method to specifically measure myelin content in vivo. PET using the benzothiazole derivative 11C-PiB has been successfully used to quantify myelin content changes in humans. Stilbene derivatives, such as 11C-MeDAS, have also been shown to bind to myelin in animals and are considered a promising radiopharmaceutical class for myelin imaging. Fluorinated compounds from both classes are now commercially available and thus should constitute clinically useful myelin radiotracers. The aim of this study is to provide a head-to-head comparison of 18F-florbetaben, 18F-florbetapir, 18F-flutemetamol, 11C-MeDAS, and 11C-PiB with regard to brain kinetics and binding in white matter (WM). METHODS Four baboons underwent a 90-min dynamic PET scan for each radioligand. Arterial blood samples were collected during the exam for each radiotracer, except for 18F-florbetapir, to obtain a radiometabolite-corrected input function. Standardized uptake value ratio between 75 at 90 min (SUVR75-90), binding potential (BP) estimated with Logan method with input function, and distribution volume ratio (DVR) estimated with Logan reference method (using cerebellar gray matter as reference region) were calculated in WM and compared between tracers using mixed effect models. RESULTS In WM, 18F-florbetapir had the highest SUVR75-90 (1.38 ± 0.03), followed by 18F-flutemetamol (1.34 ± 0.02), 18F-florbetaben (1.32 ± 0.07), 11C-MeDAS (1.27 ± 0.04), and 11C-PiB (1.25 ± 0.07). With regard to BP, 18F-florbetaben had the highest value (0.32 ± 0.06) compared with 18F-flutemetamol (0.20 ± 0.03), 11C-MeDAS (0.17 ± 0.03), and 11C-PiB (0.16 ± 0.03). No difference in DVR was detected between 18F-florbetaben (1.26 ± 0.06) and 18F-florbetapir (1.27 ± 0.03), but both were significantly higher in DVR than 18F-flutemetamol (1.17 ± 0.02), 11C-MeDAS (1.16 ± 0.03), and 11C-PiB (1.14 ± 0.02). CONCLUSIONS Given their higher binding and longer half-life, our study indicates that 18F-florbetapir and 18F-florbetaben are promising tracers for myelin imaging which are readily available for clinical application in demyelinating diseases.
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Affiliation(s)
- Sylvain Auvity
- UMR 1023 IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm , Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Matteo Tonietto
- Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital de la Pitié Salpêtrière, Inserm UMR S 1127, CNRS UMR 7225, Paris, France
| | - Fabien Caillé
- UMR 1023 IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm , Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Benedetta Bodini
- Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital de la Pitié Salpêtrière, Inserm UMR S 1127, CNRS UMR 7225, Paris, France
| | - Michel Bottlaender
- UMR 1023 IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm , Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Nicolas Tournier
- UMR 1023 IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm , Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Bertrand Kuhnast
- UMR 1023 IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm , Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Bruno Stankoff
- Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital de la Pitié Salpêtrière, Inserm UMR S 1127, CNRS UMR 7225, Paris, France.
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16
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Abstract
Myelination is an important process that takes place also in the periphery during development and in the adulthood. Myelin serves as an electric isolator for axons, leading to a fast conduction of the action potential, and provides trophic support for the axon, both aspects highly important for the proper function of the nervous system. In the central nervous system, myelination starts shortly after birth and cells from the oligodendrocyte lineage tightly regulate this process during the whole life span. Initially, it was thought that under physiological conditions myelin generation only occurs in early postnatal development and that myelination stops at early adult ages. Historically, the process of myelination has mainly been studied in fixed tissue, and predominantly analyzed by electron microscopy, bringing valuable insights in the structure and distribution of myelin in the central nervous system. Nevertheless, the outdated notion of the static nature of myelin during adulthood was challenged in the past decades by the development of new techniques bringing in a new picture of a lively structure that is in constant remodeling under physiological and disease conditions. As fixed tissue can only provide information at a specific timepoint, the necessity of new techniques to study this process in vivo has become clear. In this chapter, we will review some of the latest techniques developed in order to study myelin and the oligodendrocyte lineage, as these cells are important for the formation and restructuration of the myelin. We will also introduce a protocol to prepare a cranial window to study NG2-glia (also known as oligodendrocyte progenitor cells) of the cerebral cortex in vivo, by 2-photon laser scanning microscopy. However, this technique can also be performed to study other cell populations or structures such as myelin, which will be discussed in this chapter as well. Despite being simple, this protocol has shown to be powerful to study the oligodendrocyte lineage and potentially is applicable to study myelin in vivo, which could turn into a key technique in the understanding of myelination and other functions that the oligodendrocyte lineage might have under physiological and disease conditions.
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17
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Tiwari AD, Zhu J, You J, Eck B, Zhu J, Wang X, Wang X, Wang B, Silver J, Wilson D, Wu C, Wang Y. Novel 18F-Labeled Radioligands for Positron Emission Tomography Imaging of Myelination in the Central Nervous System. J Med Chem 2019; 62:4902-4914. [PMID: 31042384 DOI: 10.1021/acs.jmedchem.8b01354] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myelin is the protective sheath that surrounds nerves in vertebrates to protect axons, which thereby facilitates impulse conduction. Damage to myelin is associated with many neurodegenerative diseases such as multiple sclerosis and also includes spinal cord injury (SCI). The small size of the spinal cord poses formidable challenges to in vivo monitoring of myelination, which we investigated via conducting a structure-activity relationship study to determine the optimum positron-emitting agent to use for imaging myelin using positron emission tomography (PET). From these studies, [18F]PENDAS was identified as the lead agent to use in conjunction with PET imaging to delineate the integrity of spinal cord myelin. A subsequent in vivo PET imaging study of [18F]PENDAS in rats with SCI showed promising pharmacokinetic results that justify further development of imaging markers for diagnosing myelin-related diseases. Additionally, [18F]PENDAS could be valuable in determining the efficacy of therapies that are currently under development.
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Affiliation(s)
| | | | | | | | | | - Xu Wang
- Department of Radiology , Binzhou Medical University , Binzhou , Shandong 256603 , China
| | - Xizhen Wang
- Department of Radiology , Weifang Medical University , Weifang , Shandong 261053 , China
| | - Bin Wang
- Department of Radiology , Binzhou Medical University , Binzhou , Shandong 256603 , China
| | | | | | | | - Yanming Wang
- Department of Radiology , Binzhou Medical University , Binzhou , Shandong 256603 , China
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18
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Bauckneht M, Capitanio S, Raffa S, Roccatagliata L, Pardini M, Lapucci C, Marini C, Sambuceti G, Inglese M, Gallo P, Cecchin D, Nobili F, Morbelli S. Molecular imaging of multiple sclerosis: from the clinical demand to novel radiotracers. EJNMMI Radiopharm Chem 2019; 4:6. [PMID: 31659498 PMCID: PMC6453990 DOI: 10.1186/s41181-019-0058-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/21/2019] [Indexed: 12/13/2022] Open
Abstract
Background Brain PET imaging with different tracers is mainly clinically used in the field of neurodegenerative diseases and brain tumors. In recent years, the potential usefulness of PET has also gained attention in the field of MS. In fact, MS is a complex disease and several processes can be selected as a target for PET imaging. The use of PET with several different tracers has been mainly evaluated in the research setting to investigate disease pathophysiology (i.e. phenotypes, monitoring of progression) or to explore its use a surrogate end-point in clinical trials. Results We have reviewed PET imaging studies in MS in humans and animal models. Tracers have been grouped according to their pathophysiological targets (ie. tracers for myelin kinetic, neuroinflammation, and neurodegeneration). The emerging clinical indication for brain PET imaging in the differential diagnosis of suspected tumefactive demyelinated plaques as well as the clinical potential provided by PET images in view of the recent introduction of PET/MR technology are also addressed. Conclusion While several preclinical and fewer clinical studies have shown results, full-scale clinical development programs are needed to translate molecular imaging technologies into a clinical reality that could ideally fit into current precision medicine perspectives.
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Affiliation(s)
- Matteo Bauckneht
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.
| | - Selene Capitanio
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy
| | - Stefano Raffa
- Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy
| | - Luca Roccatagliata
- Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy.,Neuroradiology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Matteo Pardini
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy.,Clinica Neurologica, IRCCS Ospedale Policlinico, San Martino, Genoa, Italy
| | - Caterina Lapucci
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy
| | - Cecilia Marini
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.,CNR Institute of Molecular Bioimaging and Physiology, Milan, Italy
| | - Gianmario Sambuceti
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.,Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy
| | - Matilde Inglese
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy.,Clinica Neurologica, IRCCS Ospedale Policlinico, San Martino, Genoa, Italy
| | - Paolo Gallo
- Multiple Sclerosis Centre of the Veneto Region, Department of Neurosciences DNS, University of Padua, Padua, Italy
| | - Diego Cecchin
- Nuclear Medicine Unit, Department of Medicine-DIMED, Padova University Hospital, Padua, Italy.,Padua Neuroscience Center, University of Padua, Padua, Italy
| | - Flavio Nobili
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy.,Clinica Neurologica, IRCCS Ospedale Policlinico, San Martino, Genoa, Italy
| | - Silvia Morbelli
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.,Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy
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19
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Stankoff B, Poirion E, Tonietto M, Bodini B. Exploring the heterogeneity of MS lesions using positron emission tomography: a reappraisal of their contribution to disability. Brain Pathol 2018; 28:723-734. [PMID: 30020560 PMCID: PMC8099240 DOI: 10.1111/bpa.12641] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 07/09/2018] [Indexed: 12/22/2022] Open
Abstract
The biological mechanisms driving disability worsening in multiple sclerosis (MS) are only partly understood. Monitoring changes in lesion load on MRI has a limited predictive value on the progression of clinical disability, and there is an essential need for novel imaging markers specific for the main candidate mechanisms underlying neurodegeneration which include failing myelin repair, innate immune cell activation and gray matter neuronal damage. Positron Emission Tomography (PET) is an imaging technology based on the injection of radiotracers directed against specific molecular targets, which has recently allowed the selective quantification in-vivo of the key biological mechanisms relevant to MS pathophysiology. Pilot PET studies performed in patients with all forms of MS allowed to revisit the contribution of MS lesions to disability worsening and showed that the evolution of lesions toward chronic activation, together with their remyelination profile were relevant predictors of disability worsening. PET offers the opportunity to bridge a critical gap between neuropathology and in-vivo imaging. This technique provides an original approach to disentangle some of the most relevant pathological components driving MS progression, to follow-up their temporal evolution, to investigate their clinical relevance and to evaluate novel therapeutics aimed to prevent disease progression.
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Affiliation(s)
- Bruno Stankoff
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
- AP‐HPHôpital Saint‐AntoineParisFrance
| | - Emilie Poirion
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
| | - Matteo Tonietto
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
| | - Benedetta Bodini
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
- AP‐HPHôpital Saint‐AntoineParisFrance
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20
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Czéh B, Nagy SA. Clinical Findings Documenting Cellular and Molecular Abnormalities of Glia in Depressive Disorders. Front Mol Neurosci 2018. [PMID: 29535607 PMCID: PMC5835102 DOI: 10.3389/fnmol.2018.00056] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Depressive disorders are complex, multifactorial mental disorders with unknown neurobiology. Numerous theories aim to explain the pathophysiology. According to the “gliocentric theory”, glial abnormalities are responsible for the development of the disease. The aim of this review article is to summarize the rapidly growing number of cellular and molecular evidences indicating disturbed glial functioning in depressive disorders. We focus here exclusively on the clinical studies and present the in vivo neuroimaging findings together with the postmortem molecular and histopathological data. Postmortem studies demonstrate glial cell loss while the in vivo imaging data reveal disturbed glial functioning and altered white matter microstructure. Molecular studies report on altered gene expression of glial specific genes. In sum, the clinical findings provide ample evidences on glial pathology and demonstrate that all major glial cell types are affected. However, we still lack convincing theories explaining how the glial abnormalities develop and how exactly contribute to the emotional and cognitive disturbances. Abnormal astrocytic functioning may lead to disturbed metabolism affecting ion homeostasis and glutamate clearance, which in turn, affect synaptic communication. Abnormal oligodendrocyte functioning may disrupt the connectivity of neuronal networks, while microglial activation indicates neuroinflammatory processes. These cellular changes may relate to each other or they may indicate different endophenotypes. A theory has been put forward that the stress-induced inflammation—mediated by microglial activation—triggers a cascade of events leading to damaged astrocytes and oligodendroglia and consequently to their dysfunctions. The clinical data support the “gliocentric” theory, but future research should clarify whether these glial changes are truly the cause or simply the consequences of this devastating disorder.
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Affiliation(s)
- Boldizsár Czéh
- Neurobiology of Stress Research Group, Szentágothai Research Center, University of Pécs, Pécs, Hungary.,Department of Laboratory Medicine, University of Pécs, Medical School, Pécs, Hungary
| | - Szilvia A Nagy
- Neurobiology of Stress Research Group, Szentágothai Research Center, University of Pécs, Pécs, Hungary.,Department of Neurosurgery, University of Pécs, Medical School, Pécs, Hungary.,MTA-PTE, Clinical Neuroscience MR Research Group, Pécs, Hungary.,Pécs Diagnostic Centre, Pécs, Hungary
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21
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Brugarolas P, Sánchez-Rodríguez JE, Tsai HM, Basuli F, Cheng SH, Zhang X, Caprariello AV, Lacroix JJ, Freifelder R, Murali D, DeJesus O, Miller RH, Swenson RE, Chen CT, Herscovitch P, Reich DS, Bezanilla F, Popko B. Development of a PET radioligand for potassium channels to image CNS demyelination. Sci Rep 2018; 8:607. [PMID: 29330383 PMCID: PMC5766510 DOI: 10.1038/s41598-017-18747-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/16/2017] [Indexed: 01/22/2023] Open
Abstract
Central nervous system (CNS) demyelination represents the pathological hallmark of multiple sclerosis (MS) and contributes to other neurological conditions. Quantitative and specific imaging of demyelination would thus provide critical clinical insight. Here, we investigated the possibility of targeting axonal potassium channels to image demyelination by positron emission tomography (PET). These channels, which normally reside beneath the myelin sheath, become exposed upon demyelination and are the target of the MS drug, 4-aminopyridine (4-AP). We demonstrate using autoradiography that 4-AP has higher binding in non-myelinated and demyelinated versus well-myelinated CNS regions, and describe a fluorine-containing derivative, 3-F-4-AP, that has similar pharmacological properties and can be labeled with 18F for PET imaging. Additionally, we demonstrate that [18F]3-F-4-AP can be used to detect demyelination in rodents by PET. Further evaluation in Rhesus macaques shows higher binding in non-myelinated versus myelinated areas and excellent properties for brain imaging. Together, these data indicate that [18F]3-F-4-AP may be a valuable PET tracer for detecting CNS demyelination noninvasively.
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Affiliation(s)
- Pedro Brugarolas
- Department of Neurology, University of Chicago, Chicago, IL, USA. .,Massachusetts General Hospital, Boston, MA, USA.
| | - Jorge E Sánchez-Rodríguez
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Hsiu-Ming Tsai
- Department of Radiology, University of Chicago, Chicago, IL, USA
| | - Falguni Basuli
- Imaging Probe Development Center, NIH/NHLBI, Bethesda, MD, USA
| | - Shih-Hsun Cheng
- Department of Radiology, University of Chicago, Chicago, IL, USA
| | - Xiang Zhang
- Imaging Probe Development Center, NIH/NHLBI, Bethesda, MD, USA
| | - Andrew V Caprariello
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.,University of Calgary, Calgary, Alberta, Canada
| | - Jerome J Lacroix
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,Western University of Health Sciences, Pomona, CA, USA
| | | | - Dhanabalan Murali
- Department of Medical Physics, University of Wisconsin at Madison, Madison, WI, USA
| | - Onofre DeJesus
- Department of Medical Physics, University of Wisconsin at Madison, Madison, WI, USA
| | - Robert H Miller
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.,George Washington University, Washington, DC, USA
| | - Rolf E Swenson
- Imaging Probe Development Center, NIH/NHLBI, Bethesda, MD, USA
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, IL, USA
| | | | - Daniel S Reich
- Translational Neuroradiology Section, NIH/NINDS, Bethesda, MD, USA
| | - Francisco Bezanilla
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Brian Popko
- Department of Neurology, University of Chicago, Chicago, IL, USA.
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22
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Mahajan KR, Ontaneda D. The Role of Advanced Magnetic Resonance Imaging Techniques in Multiple Sclerosis Clinical Trials. Neurotherapeutics 2017; 14:905-923. [PMID: 28770481 PMCID: PMC5722766 DOI: 10.1007/s13311-017-0561-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Magnetic resonance imaging has been crucial in the development of anti-inflammatory disease-modifying treatments. The current landscape of multiple sclerosis clinical trials is currently expanding to include testing not only of anti-inflammatory agents, but also neuroprotective, remyelinating, neuromodulating, and restorative therapies. This is especially true of therapies targeting progressive forms of the disease where neurodegeneration is a prominent feature. Imaging techniques of the brain and spinal cord have rapidly evolved in the last decade to permit in vivo characterization of tissue microstructural changes, connectivity, metabolic changes, neuronal loss, glial activity, and demyelination. Advanced magnetic resonance imaging techniques hold significant promise for accelerating the development of different treatment modalities targeting a variety of pathways in MS.
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Affiliation(s)
- Kedar R Mahajan
- Mellen Center for Multiple Sclerosis Treatment and Research, Cleveland Clinic, 9500 Euclid Avenue, U-10, Cleveland, OH, 44195, USA
| | - Daniel Ontaneda
- Mellen Center for Multiple Sclerosis Treatment and Research, Cleveland Clinic, 9500 Euclid Avenue, U-10, Cleveland, OH, 44195, USA.
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23
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Wu C, Eck B, Zhang S, Zhu J, Tiwari AD, Zhang Y, Zhu Y, Zhang J, Wang B, Wang X, Wang X, You J, Wang J, Guan Y, Liu X, Yu X, Trapp BD, Miller R, Silver J, Wilson D, Wang Y. Discovery of 1,2,3-Triazole Derivatives for Multimodality PET/CT/Cryoimaging of Myelination in the Central Nervous System. J Med Chem 2017; 60:987-999. [DOI: 10.1021/acs.jmedchem.6b01328] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | | | | | | | | | | | | | - Jinming Zhang
- Department
of Nuclear Medicine, PLA General Hospital, Beijing 100853, China
| | - Bin Wang
- Department
of Radiology, Bingzhou Medical University, Binzhou, Shandong 256603, China
| | - Xizhen Wang
- Department
of Radiology, Bingzhou Medical University, Binzhou, Shandong 256603, China
| | - Xu Wang
- Department
of Radiology, Bingzhou Medical University, Binzhou, Shandong 256603, China
| | | | | | | | | | | | - Bruce D. Trapp
- Department
of Neurosciences, Cleveland Clinic, Cleveland, Ohio 44195, United States
| | - Robert Miller
- Department
of Anatomy and Regenerative Biology, George Washington University, Washington, D.C. 20037, United States
| | | | | | - Yanming Wang
- Department
of Radiology, Bingzhou Medical University, Binzhou, Shandong 256603, China
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24
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Abstract
Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system. Magnetic resonance imaging (MRI) is sensitive to lesion formation both in the brain and spinal cord. Imaging plays a prominent role in the diagnosis and monitoring of MS. Over a dozen anti-inflammatory therapies are approved for MS and the development of many of these medications was made possible through the use of contrast-enhancing lesions on MRI as a phase II outcome. A similar phase II outcome method for the neurodegeneration that underlies progressive courses of the disease is still unavailable. Although magnetic resonance is an invaluable tool for the diagnosis and monitoring of treatment effects in MS, several imaging barriers still exist. In general, MRI is less sensitive to gray matter lesions, lacks pathological specificity, and does not provide quantitative data easily. Several advanced imaging methods including diffusion tensor imaging, magnetization transfer, functional MRI, myelin water fraction imaging, ultra-high field MRI, positron emission tomography, and optical coherence tomography of the retina study promising ways of overcoming the difficulties in MS imaging.
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Affiliation(s)
- Daniel Ontaneda
- Mellen Center for Multiple Sclerosis, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
| | - Robert J Fox
- Mellen Center for Multiple Sclerosis, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
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25
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Bodini B, Stankoff B. Imaging Central Nervous System Demyelination and Remyelination by Positron-Emission Tomography. Brain Plast 2016; 2:93-98. [PMID: 29765850 PMCID: PMC5928544 DOI: 10.3233/bpl-160042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Positron Emission Tomography (PET), an imaging technique based on the injection of radiotracers directed against specific biological targets within brain tissues, within brain tissues, is a specific and sensitive technique which offers the unique opportunity to quantify myelin dynamics in the central nervous system. Several stilbene and benzothiazole derivatives have been repurposed to image myelin by PET. In demyelinating and dysmyelinating models, selected radiotracers were shown to reliably quantify demyelination and remyelination, allowing a translational approach in humans. A pilot study in subjects with active relapsing MS using PET and the most available benzothiazole derivative, [11C]PIB, supported the hypothesis that this technique is able to quantify myelin content in multiple sclerosis (MS) lesions and to capture dynamic demyelination and remyelination over time. This study highlighted for the first time in vivo the prognostic value of individual profiles of remyelination on the disease course. In future, the clinical application of myelin PET will be pushed forward thanks to the availability of novel fluorinated tracers for myelin, together with the setting up of non invasive quantification procedures and the use of powerful PET-MR systems. This will enable to address in vivo critical unanswered questions about the pathogenesis of remyelination, and to measure the efficacy of emerging promyelinating drugs in early-phase therapeutic trials.
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Affiliation(s)
- Benedetta Bodini
- Sorbonne Université, UPMC Paris 06, Institut du Cerveau et de la Moelle épiniére, ICM, Hôpital de la Pitié Salpêtriére, Inserm UMR S 1127, CNRS UMR 7225, Paris, France.,APHP, Assistance Publique des Hôpitaux de Paris, Hôpitaux Saint Antoine and Pitié-Salpêtriére, Paris, France
| | - Bruno Stankoff
- Sorbonne Université, UPMC Paris 06, Institut du Cerveau et de la Moelle épiniére, ICM, Hôpital de la Pitié Salpêtriére, Inserm UMR S 1127, CNRS UMR 7225, Paris, France.,APHP, Assistance Publique des Hôpitaux de Paris, Hôpitaux Saint Antoine and Pitié-Salpêtriére, Paris, France
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26
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Poutiainen P, Jaronen M, Quintana FJ, Brownell AL. Precision Medicine in Multiple Sclerosis: Future of PET Imaging of Inflammation and Reactive Astrocytes. Front Mol Neurosci 2016; 9:85. [PMID: 27695400 PMCID: PMC5023680 DOI: 10.3389/fnmol.2016.00085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 08/30/2016] [Indexed: 12/29/2022] Open
Abstract
Non-invasive molecular imaging techniques can enhance diagnosis to achieve successful treatment, as well as reveal underlying pathogenic mechanisms in disorders such as multiple sclerosis (MS). The cooperation of advanced multimodal imaging techniques and increased knowledge of the MS disease mechanism allows both monitoring of neuronal network and therapeutic outcome as well as the tools to discover novel therapeutic targets. Diverse imaging modalities provide reliable diagnostic and prognostic platforms to better achieve precision medicine. Traditionally, magnetic resonance imaging (MRI) has been considered the golden standard in MS research and diagnosis. However, positron emission tomography (PET) imaging can provide functional information of molecular biology in detail even prior to anatomic changes, allowing close follow up of disease progression and treatment response. The recent findings support three major neuroinflammation components in MS: astrogliosis, cytokine elevation, and significant changes in specific proteins, which offer a great variety of specific targets for imaging purposes. Regardless of the fact that imaging of astrocyte function is still a young field and in need for development of suitable imaging ligands, recent studies have shown that inflammation and astrocyte activation are related to progression of MS. MS is a complex disease, which requires understanding of disease mechanisms for successful treatment. PET is a precise non-invasive imaging method for biochemical functions and has potential to enhance early and accurate diagnosis for precision therapy of MS. In this review we focus on modulation of different receptor systems and inflammatory aspect of MS, especially on activation of glial cells, and summarize the recent findings of PET imaging in MS and present the most potent targets for new biomarkers with the main focus on experimental MS research.
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Affiliation(s)
- Pekka Poutiainen
- Athinoula A Martinos Biomedical Imaging Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA, USA
| | - Merja Jaronen
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Francisco J. Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Anna-Liisa Brownell
- Athinoula A Martinos Biomedical Imaging Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA, USA
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27
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Insight into the Molecular Imaging of Alzheimer's Disease. Int J Biomed Imaging 2016; 2016:7462014. [PMID: 26880871 PMCID: PMC4736963 DOI: 10.1155/2016/7462014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/16/2015] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease is a complex neurodegenerative disease affecting millions of individuals worldwide. Earlier it was diagnosed only via clinical assessments and confirmed by postmortem brain histopathology. The development of validated biomarkers for Alzheimer's disease has given impetus to improve diagnostics and accelerate the development of new therapies. Functional imaging like positron emission tomography (PET), single photon emission computed tomography (SPECT), functional magnetic resonance imaging (fMRI), and proton magnetic resonance spectroscopy provides a means of detecting and characterising the regional changes in brain blood flow, metabolism, and receptor binding sites that are associated with Alzheimer's disease. Multimodal neuroimaging techniques have indicated changes in brain structure and metabolic activity, and an array of neurochemical variations that are associated with neurodegenerative diseases. Radiotracer-based PET and SPECT potentially provide sensitive, accurate methods for the early detection of disease. This paper presents a review of neuroimaging modalities like PET, SPECT, and selected imaging biomarkers/tracers used for the early diagnosis of AD. Neuroimaging with such biomarkers and tracers could achieve a much higher diagnostic accuracy for AD and related disorders in the future.
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28
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Quantification of [(11)C]PIB PET for imaging myelin in the human brain: a test-retest reproducibility study in high-resolution research tomography. J Cereb Blood Flow Metab 2015; 35:1771-82. [PMID: 26058700 PMCID: PMC4635232 DOI: 10.1038/jcbfm.2015.120] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 04/01/2015] [Accepted: 05/05/2015] [Indexed: 01/12/2023]
Abstract
An accurate in vivo measure of myelin content is essential to deepen our insight into the mechanisms underlying demyelinating and dysmyelinating neurological disorders, and to evaluate the effects of emerging remyelinating treatments. Recently [(11)C]PIB, a positron emission tomography (PET) tracer originally conceived as a beta-amyloid marker, has been shown to be sensitive to myelin changes in preclinical models and humans. In this work, we propose a reference-region methodology for the voxelwise quantification of brain white-matter (WM) binding for [(11)C]PIB. This methodology consists of a supervised procedure for the automatic extraction of a reference region and the application of the Logan graphical method to generate distribution volume ratio (DVR) maps. This approach was assessed on a test-retest group of 10 healthy volunteers using a high-resolution PET tomograph. The [(11)C]PIB PET tracer binding was shown to be up to 23% higher in WM compared with gray matter, depending on the image reconstruction. The DVR estimates were characterized by high reliability (outliers <1%) and reproducibility (intraclass correlation coefficient (ICC) >0.95). [(11)C]PIB parametric maps were also found to be significantly correlated (R(2)>0.50) to mRNA expressions of the most represented proteins in the myelin sheath. On the contrary, no correlation was found between [(11)C]PIB imaging and nonmyelin-associated proteins.
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29
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Promteangtrong C, Kolber M, Ramchandra P, Moghbel M, Houshmand S, Schöll M, Werner TJ, Alavi A, Buchpiguel C. Multimodality Imaging Approaches in Alzheimer's disease. Part II: 1H MR spectroscopy, FDG PET and Amyloid PET. Dement Neuropsychol 2015; 9:330-342. [PMID: 29213982 PMCID: PMC5619315 DOI: 10.1590/1980-57642015dn94000330] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/17/2015] [Indexed: 01/01/2023] Open
Abstract
In this Part II review, as a complement to the Part I published in this supplement, the authors cover the imaging techniques that evaluates the Alzheimer's disease according to the different metabolic and molecular profiles. In this section MR spectroscopy, FDG-PET and amyloid PET are deeply discussed.
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Affiliation(s)
| | - Marcus Kolber
- Department of Radiology, University of Pennsylvania
School of Medicine, Philadelphia, Pennsylvania, USA
| | - Priya Ramchandra
- Department of Radiology, University of Pennsylvania
School of Medicine, Philadelphia, Pennsylvania, USA
| | - Mateen Moghbel
- Stanford University School of Medicine, Stanford,
California
| | - Sina Houshmand
- Department of Radiology, University of Pennsylvania
School of Medicine, Philadelphia, Pennsylvania, USA
| | - Michael Schöll
- Karolinska Institutet, Alzheimer Neurobiology Center,
Stockholm, Sweden
| | - Thomas J. Werner
- Department of Radiology, University of Pennsylvania
School of Medicine, Philadelphia, Pennsylvania, USA
| | - Abass Alavi
- Department of Radiology, University of Pennsylvania
School of Medicine, Philadelphia, Pennsylvania, USA
| | - Carlos Buchpiguel
- Nuclear Medicine Service, Instituto do Cancer do Estado
de São Paulo, University of São Paulo, São Paulo, Brazil
- Nuclear Medicine Center, Radiology Institute, University
of São Paulo General Hospital , São Paulo, Brazil
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30
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Matthews PM, Datta G. Positron-emission tomography molecular imaging of glia and myelin in drug discovery for multiple sclerosis. Expert Opin Drug Discov 2015; 10:557-70. [PMID: 25843125 DOI: 10.1517/17460441.2015.1032240] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Therapies acting on glial cells are being explored for new drug development for multiple sclerosis. Molecular imaging using positron-emission tomography (PET) could address relevant questions in early phase clinical trials. AREAS COVERED In this article, the authors critically review human PET methods that can be applied in specialised centres for imaging activated microglia and astrocytes and myelin. EXPERT OPINION Strengths of PET lie in the molecular selectivity, sensitivity and potential for absolute quantitation. Even now, translocator protein PET radioligands could be used in exploratory studies for interventions targeting brain microglial activation. The clinical and neuropathological meaningfulness of signal from PET radioligands reporting on astrocyte activation through cellular expression of either monoamine oxidase B or the I2-imidazoline receptor or metabolism of [(11)C]acetate can now explored. [(11)C] N-methyl-4,4'-diaminostilbene, a PET marker for myelin, could soon enter first human trials. However, use of any of these PET glial markers demands a well-focused hypothesis and a commitment to validation in the context of use. Enhanced access to these radioligands, standardisation of analyses and lowering the costs of using them are needed if their full promise is to be realised.
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Affiliation(s)
- Paul M Matthews
- Imperial College London, Division of Brain Sciences, Department of Medicine , E515, Burlington Danes Building, Du Cane Road, W12 0NN London , UK +44 02075942612 ; +44 02075946548 ;
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31
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Pouwels PJW, Vanderver A, Bernard G, Wolf NI, Dreha-Kulczewksi SF, Deoni SCL, Bertini E, Kohlschütter A, Richardson W, Ffrench-Constant C, Köhler W, Rowitch D, Barkovich AJ. Hypomyelinating leukodystrophies: translational research progress and prospects. Ann Neurol 2014; 76:5-19. [PMID: 24916848 DOI: 10.1002/ana.24194] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 06/05/2014] [Accepted: 06/05/2014] [Indexed: 12/11/2022]
Abstract
Hypomyelinating leukodystrophies represent a genetically heterogeneous but clinically overlapping group of heritable disorders. Current management approaches in the care of the patient with a hypomyelinating leukodystrophy include use of serial magnetic resonance imaging (MRI) to establish and monitor hypomyelination, molecular diagnostics to determine a specific etiology, and equally importantly, careful attention to neurologic complications over time. Emerging research in oligodendrocyte biology and neuroradiology with bedside applications may result in the possibility of clinical trials in the near term, yet there are significant gaps in knowledge in disease classification, characterization, and outcome measures in this group of disorders. Here we review the biological background of myelination, the clinical and genetic variability in hypomyelinating leukodystrophies, and the insights that can be obtained from current MRI techniques. In addition, we discuss ongoing research approaches to define potential outcome markers for future clinical trials.
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Affiliation(s)
- Petra J W Pouwels
- Department of Physics and Medical Technology, VU University Medical Center and Neuroscience Campus Amsterdam, Amsterdam, the Netherlands
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32
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de Paula Faria D, Vlaming ML, Copray SC, Tielen F, Anthonijsz HJ, Sijbesma JW, Buchpiguel CA, Dierckx RA, van der Hoorn JW, de Vries EF. PET Imaging of Disease Progression and Treatment Effects in the Experimental Autoimmune Encephalomyelitis Rat Model. J Nucl Med 2014; 55:1330-5. [DOI: 10.2967/jnumed.114.137216] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/17/2014] [Indexed: 12/13/2022] Open
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33
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Faria DDP, Copray S, Buchpiguel C, Dierckx R, de Vries E. PET imaging in multiple sclerosis. J Neuroimmune Pharmacol 2014; 9:468-82. [PMID: 24809810 DOI: 10.1007/s11481-014-9544-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/21/2014] [Indexed: 01/03/2023]
Abstract
Positron emission tomography (PET) is a non-invasive technique for quantitative imaging of biochemical and physiological processes in animals and humans. PET uses probes labeled with a radioactive isotope, called PET tracers, which can bind to or be converted by a specific biological target and thus can be applied to detect and monitor different aspects of diseases. The number of applications of PET imaging in multiple sclerosis is still limited. Clinical studies using PET are basically focused on monitoring changes in glucose metabolism and the presence of activated microglia/macrophages in sclerotic lesions. In preclinical studies, PET imaging of targets for other processes, like demyelination and remyelination, has been investigated and may soon be translated to clinical applications. Moreover, more PET tracers that could be relevant for MS are available now, but have not been studied in this context yet. In this review, we summarize the PET imaging studies performed in multiple sclerosis up to now. In addition, we will identify potential applications of PET imaging of processes or targets that are of interest to MS research, but have yet remained largely unexplored.
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Affiliation(s)
- Daniele de Paula Faria
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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34
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Kepe V, Moghbel MC, Långström B, Zaidi H, Vinters HV, Huang SC, Satyamurthy N, Doudet D, Mishani E, Cohen RM, Høilund-Carlsen PF, Alavi A, Barrio JR. Amyloid-β positron emission tomography imaging probes: a critical review. J Alzheimers Dis 2014; 36:613-31. [PMID: 23648516 DOI: 10.3233/jad-130485] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The rapidly rising prevalence and cost of Alzheimer's disease in recent decades has made the imaging of amyloid-β deposits the focus of intense research. Several amyloid imaging probes with purported specificity for amyloid-β plaques are currently at various stages of FDA approval. However, a number of factors appear to preclude these probes from clinical utilization. As the available "amyloid specific" positron emission tomography imaging probes have failed to demonstrate diagnostic value and have shown limited utility for monitoring therapeutic interventions in humans, a debate on their significance has emerged. The aim of this review is to identify and discuss critically the scientific issues contributing to the extensive inconsistencies reported in the literature on their purported in vivo amyloid specificity and potential utilization in patients.
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Affiliation(s)
- Vladimir Kepe
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California-Los Angeles, CA 90095, USA
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35
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de Paula Faria D, de Vries EFJ, Sijbesma JWA, Buchpiguel CA, Dierckx RAJO, Copray SCVM. PET imaging of glucose metabolism, neuroinflammation and demyelination in the lysolecithin rat model for multiple sclerosis. Mult Scler 2014; 20:1443-52. [DOI: 10.1177/1352458514526941] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background: Injection of lysolecithin in the central nervous system results in demyelination accompanied by local activation of microglia and recruitment of monocytes. Positron-emission tomography (PET) imaging, using specific tracers, may be an adequate technique to monitor these events in vivo and therefore may become a tool for monitoring disease progression in multiple sclerosis (MS) patients. Objectives: The objective of this paper is to evaluate the potential of PET imaging in monitoring local lesions, using [11C]MeDAS, [11C]PK11195 and [18F]FDG as PET tracers for myelin density, microglia activation and glucose metabolism, respectively. Methods: Sprague-Dawley rats were stereotactically injected with either 1% lysolecithin or saline in the corpus callosum and striatum of the right brain hemisphere. PET imaging was performed three days, one week and four weeks after injection. Animals were terminated after PET imaging and the brains were explanted for (immuno)histochemical analysis. Results: PET imaging was able to detect local demyelination induced by lysolecithin in the corpus callosum and striatum with [11C]MeDAS and concomitant microglia activation and monocyte recruitment with [11C]PK11195. [18F]FDG imaging demonstrated that glucose metabolism was maintained in the demyelinated lesions. Conclusion: PET imaging with multiple tracers allows simultaneous in vivo monitoring of myelin density, neuroinflammation and brain metabolism in small MS-like lesions, indicating its potential to monitor disease progression in MS patients.
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Affiliation(s)
- Daniele de Paula Faria
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Erik FJ de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Jurgen WA Sijbesma
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Carlos A Buchpiguel
- Center of Nuclear Medicine, University of São Paulo, University of São Paulo Medical School, Brazil
| | - Rudi AJO Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Sjef CVM Copray
- Department of Neuroscience, University of Groningen, University Medical Center Groningen, The Netherlands
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36
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Faria DDP, Copray S, Sijbesma JWA, Willemsen ATM, Buchpiguel CA, Dierckx RAJO, de Vries EFJ. PET imaging of focal demyelination and remyelination in a rat model of multiple sclerosis: comparison of [11C]MeDAS, [11C]CIC and [11C]PIB. Eur J Nucl Med Mol Imaging 2014; 41:995-1003. [PMID: 24499866 DOI: 10.1007/s00259-013-2682-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 12/20/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE In this study, we compared the ability of [(11)C]CIC, [(11)C]MeDAS and [(11)C]PIB to reveal temporal changes in myelin content in focal lesions in the lysolecithin rat model of multiple sclerosis. Pharmacokinetic modelling was performed to determine the best method to quantify tracer uptake. METHODS Sprague-Dawley rats were stereotactically injected with either 1 % lysolecithin or saline into the corpus callosum and striatum of the right brain hemisphere. Dynamic PET imaging with simultaneous arterial blood sampling was performed 7 days after saline injection (control group), 7 days after lysolecithin injection (demyelination group) and 4 weeks after lysolecithin injection (remyelination group). RESULTS The kinetics of [(11)C]CIC, [(11)C]MeDAS and [(11)C]PIB was best fitted by Logan graphical analysis, suggesting that tracer binding is reversible. Compartment modelling revealed that all tracers were fitted best with the reversible two-tissue compartment model. Tracer uptake and distribution volume in lesions were in agreement with myelin status. However, the slow kinetics and homogeneous brain uptake of [(11)C]CIC make this tracer less suitable for in vivo PET imaging. [(11)C]PIB showed good uptake in the white matter in the cerebrum, but [(11)C]PIB uptake in the cerebellum was low, despite high myelin density in this region. [(11)C]MeDAS distribution correlated well with myelin density in different brain regions. CONCLUSION This study showed that PET imaging of demyelination and remyelination processes in focal lesions is feasible. Our comparison of three myelin tracers showed that [(11)C]MeDAS has more favourable properties for quantitative PET imaging of demyelinated and remyelinated lesions throughout the CNS than [(11)C]CIC and [(11)C]PIB.
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Affiliation(s)
- Daniele de Paula Faria
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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PET imaging of demyelination and remyelination in the cuprizone mouse model for multiple sclerosis: A comparison between [11C]CIC and [11C]MeDAS. Neuroimage 2014; 87:395-402. [DOI: 10.1016/j.neuroimage.2013.10.057] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/08/2013] [Accepted: 10/24/2013] [Indexed: 11/20/2022] Open
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Abstract
Neuroinflammation plays a central role in a variety of neurological diseases, including stroke, multiple sclerosis, Alzheimer’s disease, and malignant CNS neoplasms, among many other. Different cell types and molecular mediators participate in a cascade of events in the brain that is ultimately aimed at control, regeneration and repair, but leads to damage of brain tissue under pathological conditions. Non-invasive molecular imaging of key players in the inflammation cascade holds promise for identification and quantification of the disease process before it is too late for effective therapeutic intervention. In this review, we focus on molecular imaging techniques that target inflammatory cells and molecules that are of interest in neuroinflammation, especially those with high translational potential. Over the past decade, a plethora of molecular imaging agents have been developed and tested in animal models of (neuro)inflammation, and a few have been translated from bench to bedside. The most promising imaging techniques to visualize neuroinflammation include MRI, positron emission tomography (PET), single photon emission computed tomography (SPECT), and optical imaging methods. These techniques enable us to image adhesion molecules to visualize endothelial cell activation, assess leukocyte functions such as oxidative stress, granule release, and phagocytosis, and label a variety of inflammatory cells for cell tracking experiments. In addition, several cell types and their activation can be specifically targeted in vivo, and consequences of neuroinflammation such as neuronal death and demyelination can be quantified. As we continue to make progress in utilizing molecular imaging technology to study and understand neuroinflammation, increasing efforts and investment should be made to bring more of these novel imaging agents from the “bench to bedside.”
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Affiliation(s)
- Benjamin Pulli
- Center for Systems Biology and Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - John W Chen
- Center for Systems Biology and Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
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Abstract
PET with "β-amyloid-specific" molecular imaging probes is proposed for the measurement of brain β-amyloid protein amyloidosis in the new guidelines for diagnosis of Alzheimer disease (AD) at different levels of disease progression. This article discusses limitations of this proposed use pointing to unresolved issues and inconsistencies between PET scan results and correlation with other biomarkers, and with postmortem histopathological studies. These unresolved issues do not warrant the conclusion that PET imaging with "β-amyloid-specific" molecular imaging probes can be used as a biomarker in AD or in the various stages of disease progression.
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Affiliation(s)
- Vladimir Kepe
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles, 10833 Le Conte Avenue, CHS B2-086B, Los Angeles, CA 90095-6948, USA.
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Wu C, Zhu J, Baeslack J, Zaremba A, Hecker J, Kraso J, Matthews PM, Miller RH, Wang Y. Longitudinal positron emission tomography imaging for monitoring myelin repair in the spinal cord. Ann Neurol 2013; 74:688-98. [DOI: 10.1002/ana.23965] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 05/30/2013] [Accepted: 06/07/2013] [Indexed: 11/05/2022]
Affiliation(s)
- Chunying Wu
- Division of Radiopharmaceutical Science; Case Center for Imaging Research Department of Radiology; Case Western Reserve University; Cleveland OH
| | - Junqing Zhu
- Division of Radiopharmaceutical Science; Case Center for Imaging Research Department of Radiology; Case Western Reserve University; Cleveland OH
| | - Jonathan Baeslack
- Division of Radiopharmaceutical Science; Case Center for Imaging Research Department of Radiology; Case Western Reserve University; Cleveland OH
| | - Anita Zaremba
- Department of Neurosciences; Case Western Reserve University; Cleveland OH
| | - Jordan Hecker
- Department of Neurosciences; Case Western Reserve University; Cleveland OH
| | - Janet Kraso
- Department of Neurosciences; Case Western Reserve University; Cleveland OH
| | - Paul M. Matthews
- Division of Brain Sciences; Imperial College; London United Kingdom
- GlaxoSmithKline Research and Development; Brentford United Kingdom
| | - Robert H. Miller
- Department of Neurosciences; Case Western Reserve University; Cleveland OH
| | - Yanming Wang
- Division of Radiopharmaceutical Science; Case Center for Imaging Research Department of Radiology; Case Western Reserve University; Cleveland OH
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Frullano L, Zhu J, Miller RH, Wang Y. Synthesis and characterization of a novel gadolinium-based contrast agent for magnetic resonance imaging of myelination. J Med Chem 2013; 56:1629-40. [PMID: 23311333 DOI: 10.1021/jm301435z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Myelin is a membrane system that fosters nervous impulse conduction in the vertebrate nervous system. Myelin sheath disruption is a common characteristic of several neurodegenerative diseases such as multiple sclerosis (MS) and various leukodystrophies. To date, the diagnosis of MS is obtained using a set of criteria in which MRI observations play a central role. However, because of the lack of specificity for myelin integrity, the use of MRI as the primary diagnostic tool has not yet been accepted. In order to improve MR specificity, we began developing MR probes targeted toward myelin. In this work we describe a new myelin-targeted MR contrast agent, Gd-DODAS, based on a stilbene binding moiety and demonstrate its ability to specifically bind to myelin in vitro and in vivo. We also present evidence that Gd-DODAS generates MR contrast in vivo in T1-weighed images and in T1 maps that correlates to the myelin content.
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Affiliation(s)
- Luca Frullano
- Department of Radiology, Case Center for Imaging Research, Division of Radiopharmaceutical Science, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, Ohio 44106, United States
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Condie AG, Gerson SL, Miller RH, Wang Y. Two-photon fluorescent imaging of myelination in the spinal cord. ChemMedChem 2012; 7:2194-203. [PMID: 23136014 DOI: 10.1002/cmdc.201200343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Indexed: 11/11/2022]
Abstract
Myelination is a fundamental biological process in the vertebrate nervous system. Damage to or malformation of myelin can lead to various neurological diseases; for example, demyelination in the spinal cord is a major cause of paralysis of patients suffering from multiple sclerosis and related diseases. The ability to directly track myelin levels in the spinal cord is needed in order to assess the efficacy of therapeutics in promoting myelin repair. To address this unmet need, 4-((E)-4-((E)-4-aminostyryl)-2,5-dimethoxystyryl)-N-methylaniline, known as Case Imaging Compound (CIC), has been developed as a myelin-targeted fluorescent imaging agent that selectively binds to myelin. CIC was synthesized via an improved route and evaluated as a fluorescent probe for two-photon fluorescent imaging of myelin in the spinal cord in both demyelinated and dysmyelinated models. In vitro and ex vivo tissue staining both suggest that CIC selectively binds to in animal models. Further evaluation in animal models indicated that CIC is sensitive to differences in myelin content in healthy versus pathological myelin. CIC could potentially be useful in the development and evaluation of novel therapies for multiple sclerosis and other demyelinating diseases.
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Affiliation(s)
- Allison G Condie
- Division of Radiopharmaceutical Science, Case Center for Imaging Research, Department of Radiology, Chemistry, and Biomedical Engineering, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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Benadiba M, Luurtsema G, Wichert-Ana L, Buchpigel CA, Filho GB. New Molecular Targets for PET and SPECT Imaging in Neurodegenerative Diseases. BRAZILIAN JOURNAL OF PSYCHIATRY 2012; 34 Suppl 2:S125-36. [DOI: 10.1016/j.rbp.2012.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 02/29/2012] [Indexed: 01/23/2023]
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Wu C, Li R, Dearborn D, Wang Y. Reductive Amination with [<sup>11</sup>C]Formaldehyde: A Versatile Approach to Radiomethylation of Amines. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ijoc.2012.23030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Frullano L, Zhu J, Wang C, Wu C, Miller RH, Wang Y. Myelin imaging compound (MIC) enhanced magnetic resonance imaging of myelination. J Med Chem 2011; 55:94-105. [PMID: 22098543 DOI: 10.1021/jm201010e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The vertebrate nervous system is characterized by myelination, a fundamental biological process that protects the axons and facilitates electric pulse transduction. Damage to myelin is considered a major effect of autoimmune diseases such as multiple sclerosis (MS). Currently, therapeutic interventions are focused on protecting myelin integrity and promoting myelin repair. These efforts need to be accompanied by an effective imaging tool that correlates the disease progression with the extent of myelination. To date, magnetic resonance imaging (MRI) is the primary imaging technique to detect brain lesions in MS. However, conventional MRI cannot differentiate demyelinated lesions from other inflammatory lesions and therefore cannot predict disease progression in MS. To address this problem, we have prepared a Gd-based contrast agent, termed MIC (myelin imaging compound), which binds to myelin with high specificity. In this work, we demonstrate that MIC exhibits a high kinetic stability toward transmetalation with promising relaxometric properties. MIC was used for in vivo imaging of myelination following intracerebroventricular infusion in the rat brain. MIC was found to distribute preferentially in highly myelinated regions and was able to detect regions of focally induced demyelination.
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Affiliation(s)
- Luca Frullano
- Department of Radiology, Case Center for Imaging Research, Division of Radiopharmaceutical Science, Case Western Reserve University, Cleveland, Ohio 44106, United States
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Wang C, Wu C, Zhu J, Miller RH, Wang Y. Design, synthesis, and evaluation of coumarin-based molecular probes for imaging of myelination. J Med Chem 2011; 54:2331-40. [PMID: 21391687 DOI: 10.1021/jm101489w] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myelination represents one of the most fundamental biological processes in the vertebrate nervous system. Abnormalities and changes in myelination in the central nervous system (CNS) are seen in many neurodegenerative disorders, such as multiple sclerosis (MS). A long-standing goal has been to directly detect and quantify myelin content in order to facilitate diagnosis and therapeutic treatments of myelin-related diseases. In the course of our studies, we have developed a series of small-molecule probes (SMP) as myelin-imaging agents. Among them are coumarin derivatives, which exhibit promising brain permeability and myelin-binding properties. Herein we report a full account of the design and synthesis of coumarin-based SMPs as myelin-imaging agents. Systematic evaluation of these SMPs in both the CNS and peripheral nervous system (PNS) allowed us to identify some lead agents for potential use as fluorescent dyes for intraoperative nerve mapping in surgical operations or as radiotracers for positron emission tomography (PET) imaging of myelination.
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Affiliation(s)
- Changning Wang
- Division of Radiopharmaceutical Science, Case Center for Imaging Research, Department of Radiology, Case Western Reserve University, Cleveland, Ohio 44106, United States
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