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Zatcepin A, Kopczak A, Holzgreve A, Hein S, Schindler A, Duering M, Kaiser L, Lindner S, Schidlowski M, Bartenstein P, Albert N, Brendel M, Ziegler SI. Machine learning-based approach reveals essential features for simplified TSPO PET quantification in ischemic stroke patients. Z Med Phys 2024; 34:218-230. [PMID: 36682921 PMCID: PMC11156782 DOI: 10.1016/j.zemedi.2022.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Neuroinflammation evaluation after acute ischemic stroke is a promising option for selecting an appropriate post-stroke treatment strategy. To assess neuroinflammation in vivo, translocator protein PET (TSPO PET) can be used. However, the gold standard TSPO PET quantification method includes a 90 min scan and continuous arterial blood sampling, which is challenging to perform on a routine basis. In this work, we determine what information is required for a simplified quantification approach using a machine learning algorithm. MATERIALS AND METHODS We analyzed data from 18 patients with ischemic stroke who received 0-90 min [18F]GE-180 PET as well as T1-weigted (T1w), FLAIR, and arterial spin labeling (ASL) MRI scans. During PET scans, five manual venous blood samples at 5, 15, 30, 60, and 85 min post injection (p.i.) were drawn, and plasma activity concentration was measured. Total distribution volume (VT) was calculated using Logan plot with the full dynamic PET and an image-derived input function (IDIF) from the carotid arteries. IDIF was scaled by a calibration factor derived from all the measured plasma activity concentrations. The calculated VT values were used for training a random forest regressor. As input features for the model, we used three late PET frames (60-70, 70-80, and 80-90 min p.i.), the ASL image reflecting perfusion, the voxel coordinates, the lesion mask, and the five plasma activity concentrations. The algorithm was validated with the leave-one-out approach. To estimate the impact of the individual features on the algorithm's performance, we used Shapley Additive Explanations (SHAP). Having determined that the three late PET frames and the plasma activity concentrations were the most important features, we tested a simplified quantification approach consisting of dividing a late PET frame by a plasma activity concentration. All the combinations of frames/samples were compared by means of concordance correlation coefficient and Bland-Altman plots. RESULTS When using all the input features, the algorithm predicted VT values with high accuracy (87.8 ± 8.3%) for both lesion and non-lesion voxels. The SHAP values demonstrated high impact of the late PET frames (60-70, 70-80, and 80-90 min p.i.) and plasma activity concentrations on the VT prediction, while the influence of the ASL-derived perfusion, voxel coordinates, and the lesion mask was low. Among all the combinations of the late PET frames and plasma activity concentrations, the 70-80 min p.i. frame divided by the 30 min p.i. plasma sample produced the closest VT estimate in the ischemic lesion. CONCLUSION Reliable TSPO PET quantification is achievable by using a single late PET frame divided by a late blood sample activity concentration.
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Affiliation(s)
- Artem Zatcepin
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
| | - Anna Kopczak
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
| | - Adrien Holzgreve
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Sandra Hein
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
| | - Andreas Schindler
- Department of Neuroradiology, University Hospital, LMU Munich, Munich, Germany
| | - Marco Duering
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany; Medical Image Analysis Center (MIAC) & Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Lena Kaiser
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Martin Schidlowski
- Department of Epileptology, University Hospital Bonn, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Nathalie Albert
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sibylle I Ziegler
- Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany
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Knyzeliene A, MacAskill MG, Alcaide-Corral CJ, Morgan TEF, Henry MC, Lucatelli C, Pimlott SL, Sutherland A, Tavares AAS. [ 18F]LW223 has low non-displaceable binding in murine brain, enabling high sensitivity TSPO PET imaging. J Cereb Blood Flow Metab 2024; 44:397-406. [PMID: 37795635 PMCID: PMC10870961 DOI: 10.1177/0271678x231205661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 09/01/2023] [Accepted: 09/09/2023] [Indexed: 10/06/2023]
Abstract
Neuroinflammation is associated with a number of brain diseases, making it a common feature of cerebral pathology. Among the best-known biomarkers for neuroinflammation in Positron Emission Tomography (PET) research is the 18 kDa translocator protein (TSPO). This study aims to investigate the binding kinetics of a novel TSPO PET radiotracer, [18F]LW223, in mice and specifically assess its volume of non-displaceable binding (VND) in brain as well as investigate the use of simplified analysis approaches for quantification of [18F]LW223 PET data. Adult male mice were injected with [18F]LW223 and varying concentrations of LW223 (0.003-0.55 mg/kg) to estimate VND of [18F]LW223. Dynamic PET imaging with arterial input function studies and radiometabolite studies were conducted. Simplified quantification methods, standard uptake values (SUV) and apparent volume of distribution (VTapp), were investigated. [18F]LW223 had low VND in the brain (<10% of total binding) and low radiometabolism (∼15-20%). The 2-tissue compartment model provided the best fit for [18F]LW223 PET data, although its correlation with SUV90-120min or VTapp allowed for [18F]LW223 brain PET data quantification in healthy animals while using simpler experimental and analytical approaches. [18F]LW223 has the required properties to become a successful TSPO PET radiotracer.
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Affiliation(s)
- Agne Knyzeliene
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | - Mark G MacAskill
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | - Carlos J Alcaide-Corral
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | - Timaeus EF Morgan
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
| | | | | | - Sally L Pimlott
- West of Scotland PET Centre, Greater Glasgow and Clyde NHS Trust, Glasgow, UK
| | | | - Adriana AS Tavares
- BHF-University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Edinburgh Imaging, University of Edinburgh, Edinburgh, UK
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Zhang M, Meng H, Zhou Q, Chunyu H, He L, Meng H, Wang H, Wang Y, Sun C, Xi Y, Hai W, Huang Q, Li B, Chen S. Microglial Activation Imaging Using 18F-DPA-714 PET/MRI for Detecting Autoimmune Encephalitis. Radiology 2024; 310:e230397. [PMID: 38441089 DOI: 10.1148/radiol.230397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Background Translocator protein (TSPO) PET has been used to visualize microglial activation in neuroinflammation and is a potential imaging tool for detecting autoimmune encephalitis (AIE). Purpose To compare the detection rate between TSPO radioligand fluorine 18 (18F) DPA-714 PET and conventional MRI and assess the relationship between 18F-DPA-714 uptake and clinical features in participants with AIE. Materials and Methods Healthy volunteers and patients with AIE were enrolled in this prospective study between December 2021 and April 2023. All participants underwent hybrid brain 18F-DPA-714 PET/MRI and antibody testing. Modified Rankin scale scoring and AIE-related symptoms were assessed in participants with AIE. Positive findings were defined as intensity of 18F-DPA-714 uptake above a threshold of the mean standardized uptake value ratio (SUVR) plus 2 SD inside the corresponding brain regions of healthy controls. The McNemar test was used to compare the positive detection rate between the two imaging modalities; the independent samples t test was used to compare continuous variables; and correlation with Bonferroni correction was used to assess the relationship between 18F-DPA-714 uptake and clinical features. Results A total of 25 participants with AIE (mean age, 39.24 years ± 19.03 [SD]) and 10 healthy controls (mean age, 28.70 years ± 5.14) were included. The positive detection rate of AIE was 72% (18 of 25) using 18F-DPA-714 PET compared to 44% (11 of 25) using conventional MRI, but the difference was not statistically significant (P = .065). Participants experiencing seizures exhibited significantly higher mean SUVR in the entire cortical region than those without seizures (1.23 ± 0.21 vs 1.15 ± 0.18; P = .003). Of the 13 participants with AIE who underwent follow-up PET/MRI, 11 (85%) demonstrated reduced uptake of 18F-DPA-714 accompanied by relief of symptoms after immunosuppressive treatment. Conclusion 18F-DPA-714 PET has potential value in supplementing MRI for AIE detection. Clinical trial registration no. NCT05293405 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Zaharchuk in this issue.
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Affiliation(s)
- Min Zhang
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Huanyu Meng
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Qinming Zhou
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Hangxing Chunyu
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Lu He
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Hongping Meng
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Hanzhong Wang
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Yue Wang
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Chenwei Sun
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Yun Xi
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Wangxi Hai
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Qiu Huang
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Biao Li
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
| | - Sheng Chen
- From the Departments of Nuclear Medicine (M.Z., H.C., Hongping Meng, Y.W., C.S., Y.X., W.H., B.L.) and Neurology (Huanyu Meng, Q.Z., L.H., S.C.), Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Rd, Shanghai, China; Shanxi Medical University-Collaborative Innovation Center for Molecular Imaging of Precision Medicine, Taiyuan, China (M.Z., B.L.); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China (H.W., Q.H.); and Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China (S.C.)
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Wang Z, Song Y, Bai S, Xiang W, Zhou X, Han L, Zhu D, Guan Y. Imaging of microglia in post-stroke inflammation. Nucl Med Biol 2023; 118-119:108336. [PMID: 37028196 DOI: 10.1016/j.nucmedbio.2023.108336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 04/03/2023]
Abstract
Microglia constantly survey the central nervous system microenvironment and maintain brain homeostasis. Microglia activation, polarization and inflammatory response are of great importance in the pathophysiology of ischemic stroke. For exploring biochemical processes in vivo, positron emission tomography (PET) is a superior imaging tool. Translocator protein 18 kDa (TSPO), is a validated neuroinflammatory biomarker which is widely used to evaluate various central nervous system (CNS) pathologies in both preclinical and clinical studies. TSPO level can be elevated due to peripheral inflammatory cells infiltration and glial cells activation. Therefore, a clear understanding of the dynamic changes between microglia and TSPO is critical for interpreting PET studies and understanding the pathophysiology after ischemic stroke. Our review discusses alternative biological targets that have attracted considerable interest for the imaging of microglia activation in recent years, and the potential value of imaging of microglia in the assessment of stroke therapies.
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Hernandez VG, Lechtenberg KJ, Peterson TC, Zhu L, Lucas TA, Owah JO, Dorsey AI, Gentles AJ, Buckwalter MS. Translatome analysis reveals microglia and astrocytes to be distinct regulators of inflammation in the hyperacute and acute phases after stroke. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.14.520351. [PMID: 36824949 PMCID: PMC9949064 DOI: 10.1101/2023.02.14.520351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Neuroinflammation is a hallmark of ischemic stroke, which is a leading cause of death and long-term disability. Understanding the exact cellular signaling pathways that initiate and propagate neuroinflammation after stroke will be critical for developing immunomodulatory stroke therapies. In particular, the precise mechanisms of inflammatory signaling in the clinically relevant hyperacute period, hours after stroke, have not been elucidated. We used the RiboTag technique to obtain astrocyte and microglia-derived mRNA transcripts in a hyperacute (4 hours) and acute (3 days) period after stroke, as these two cell types are key modulators of acute neuroinflammation. Microglia initiated a rapid response to stroke at 4 hours by adopting an inflammatory profile associated with the recruitment of immune cells. The hyperacute astrocyte profile was marked by stress response genes and transcription factors, such as Fos and Jun , involved in pro-inflammatory pathways such as TNF-α. By 3 days, microglia shift to a proliferative state and astrocytes strengthen their inflammatory response. The astrocyte pro-inflammatory response at 3 days is partially driven by the upregulation of the transcription factors C/EBPβ, Spi1 , and Rel , which comprise 25% of upregulated transcription factor-target interactions. Surprisingly, few sex differences across all groups were observed. Expression and log 2 fold data for all sequenced genes are available on a user-friendly website for researchers to examine gene changes and generate hypotheses for stroke targets. Taken together our data comprehensively describe the astrocyte and microglia-specific translatome response in the hyperacute and acute period after stroke and identify pathways critical for initiating neuroinflammation.
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Ni R, Müller Herde A, Haider A, Keller C, Louloudis G, Vaas M, Schibli R, Ametamey SM, Klohs J, Mu L. In vivo Imaging of Cannabinoid Type 2 Receptors: Functional and Structural Alterations in Mouse Model of Cerebral Ischemia by PET and MRI. Mol Imaging Biol 2022; 24:700-709. [PMID: 34642898 PMCID: PMC9581861 DOI: 10.1007/s11307-021-01655-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE Stroke is one of the most prevalent vascular diseases. Non-invasive molecular imaging methods have the potential to provide critical insights into the temporal dynamics and follow alterations of receptor expression and metabolism in ischemic stroke. The aim of this study was to assess the cannabinoid type 2 receptor (CB2R) levels in transient middle cerebral artery occlusion (tMCAO) mouse models at subacute stage using positron emission tomography (PET) with our novel tracer [18F]RoSMA-18-d6 and structural imaging by magnetic resonance imaging (MRI). PROCEDURES Our recently developed CB2R PET tracer [18F]RoSMA-18-d6 was used for imaging neuroinflammation at 24 h after reperfusion in tMCAO mice. The RNA expression levels of CB2R and other inflammatory markers were analyzed by quantitative real-time polymerase chain reaction using brain tissues from tMCAO (1 h occlusion) and sham-operated mice. [18F]fluorodeoxyglucose (FDG) was included for evaluation of the cerebral metabolic rate of glucose (CMRglc). In addition, diffusion-weighted imaging and T2-weighted imaging were performed for anatomical reference and delineating the lesion in tMCAO mice. RESULTS mRNA expressions of inflammatory markers TNF-α, Iba1, MMP9 and GFAP, CNR2 were increased to 1.3-2.5 fold at 24 h after reperfusion in the ipsilateral compared to contralateral hemisphere of tMCAO mice, while mRNA expression of the neuronal marker MAP-2 was markedly reduced to ca. 50 %. Reduced [18F]FDG uptake was observed in the ischemic striatum of tMCAO mouse brain at 24 h after reperfusion. Although higher activity of [18F]RoSMA-18-d6 in ex vivo biodistribution studies and higher standard uptake value ratio (SUVR) were detected in the ischemic ipsilateral compared to contralateral striatum in tMCAO mice, the in vivo specificity of [18F]RoSMA-18-d6 was confirmed only in the CB2R-rich spleen. CONCLUSIONS This study revealed an increased [18F]RoSMA-18-d6 measure of CB2R and a reduced [18F]FDG measure of CMRglc in the ischemic striatum of tMCAO mice at subacute stage. [18F]RoSMA-18-d6 might be a promising PET tracer for detecting CB2R alterations in animal models of neuroinflammation without neuronal loss.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
| | - Adrienne Müller Herde
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Ahmed Haider
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Claudia Keller
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Georgios Louloudis
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Markus Vaas
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Roger Schibli
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Simon M Ametamey
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Linjing Mu
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland.
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland.
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Crișan G, Moldovean-Cioroianu NS, Timaru DG, Andrieș G, Căinap C, Chiș V. Radiopharmaceuticals for PET and SPECT Imaging: A Literature Review over the Last Decade. Int J Mol Sci 2022; 23:ijms23095023. [PMID: 35563414 PMCID: PMC9103893 DOI: 10.3390/ijms23095023] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 04/23/2022] [Accepted: 04/28/2022] [Indexed: 02/04/2023] Open
Abstract
Positron emission tomography (PET) uses radioactive tracers and enables the functional imaging of several metabolic processes, blood flow measurements, regional chemical composition, and/or chemical absorption. Depending on the targeted processes within the living organism, different tracers are used for various medical conditions, such as cancer, particular brain pathologies, cardiac events, and bone lesions, where the most commonly used tracers are radiolabeled with 18F (e.g., [18F]-FDG and NA [18F]). Oxygen-15 isotope is mostly involved in blood flow measurements, whereas a wide array of 11C-based compounds have also been developed for neuronal disorders according to the affected neuroreceptors, prostate cancer, and lung carcinomas. In contrast, the single-photon emission computed tomography (SPECT) technique uses gamma-emitting radioisotopes and can be used to diagnose strokes, seizures, bone illnesses, and infections by gauging the blood flow and radio distribution within tissues and organs. The radioisotopes typically used in SPECT imaging are iodine-123, technetium-99m, xenon-133, thallium-201, and indium-111. This systematic review article aims to clarify and disseminate the available scientific literature focused on PET/SPECT radiotracers and to provide an overview of the conducted research within the past decade, with an additional focus on the novel radiopharmaceuticals developed for medical imaging.
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Affiliation(s)
- George Crișan
- Faculty of Physics, Babeş-Bolyai University, Str. M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania; (G.C.); (N.S.M.-C.); (D.-G.T.)
- Department of Nuclear Medicine, County Clinical Hospital, Clinicilor 3-5, 400006 Cluj-Napoca, Romania;
| | | | - Diana-Gabriela Timaru
- Faculty of Physics, Babeş-Bolyai University, Str. M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania; (G.C.); (N.S.M.-C.); (D.-G.T.)
| | - Gabriel Andrieș
- Department of Nuclear Medicine, County Clinical Hospital, Clinicilor 3-5, 400006 Cluj-Napoca, Romania;
| | - Călin Căinap
- The Oncology Institute “Prof. Dr. Ion Chiricuţă”, Republicii 34-36, 400015 Cluj-Napoca, Romania;
| | - Vasile Chiș
- Faculty of Physics, Babeş-Bolyai University, Str. M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania; (G.C.); (N.S.M.-C.); (D.-G.T.)
- Institute for Research, Development and Innovation in Applied Natural Sciences, Babeș-Bolyai University, Str. Fântânele 30, 400327 Cluj-Napoca, Romania
- Correspondence:
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8
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Young JW, Barback CV, Stolz LA, Groman SM, Vera DR, Hoh C, Kotta KK, Minassian A, Powell SB, Brody AL. MicroPET evidence for a hypersensitive neuroinflammatory profile of gp120 mouse model of HIV. Psychiatry Res Neuroimaging 2022; 321:111445. [PMID: 35101828 DOI: 10.1016/j.pscychresns.2022.111445] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 02/07/2023]
Abstract
Despite increased survivability for people living with HIV (PLWH), HIV-related cognitive deficits persist. Determining biological mechanism(s) underlying abnormalities is critical to minimize the long-term impact of HIV. Positron emission tomography (PET) studies reveal that PLWH exhibit elevated neuroinflammation, potentially contributing to these problems. PLWH are hypersensitive to environmental insults that drive elevated inflammatory profiles. Gp120 is an envelope glycoprotein exposed on the surface of the HIV envelope which enables HIV entry into a cell contributing to HIV-related neurotoxicity. In vivo evidence for mice overexpressing gp120 (transgenic) mice exhibiting neuroinflammation remains unclear. Here, we conducted microPET imaging in gp120 transgenic and wildtype mice, using the radiotracer [(18)F]FEPPA (binds to the translocator protein expressed by activated microglial serving as a neuroinflammatory marker). Imaging was performed at baseline and 24 h after lipopolysaccharide (LPS; 5 mg/kg) treatment (endotoxin that triggers an immune response). Gp120 transgenic mice exhibited elevated [(18F)]FEPPA in response to LPS vs. wildtype mice throughout the brain including dorsal and ventral striata, hypothalamus, and hippocampus. Gp120 transgenic mice are hypersensitive to environmental inflammatory insults, consistent with PLWH, measurable in vivo. It remains to-be-determined whether this heightened sensitivity is connected to the behavioral abnormalities of these mice or sensitive to any treatments.
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Affiliation(s)
- Jared W Young
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA.
| | - Christopher V Barback
- Department of Radiology, University of California, San Diego, La Jolla California; UCSD In Vivo Cancer and Molecular Imaging Program
| | - Louise A Stolz
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA
| | - Stephanie M Groman
- Department of Neuroscience, Medical Discovery Team on Addiction, University of Minnesota
| | - David R Vera
- Department of Radiology, University of California, San Diego, La Jolla California; UCSD In Vivo Cancer and Molecular Imaging Program
| | - Carl Hoh
- Department of Radiology, University of California, San Diego, La Jolla California; UCSD In Vivo Cancer and Molecular Imaging Program
| | - Kishore K Kotta
- Department of Radiology, University of California, San Diego, La Jolla California; UCSD In Vivo Cancer and Molecular Imaging Program
| | - Arpi Minassian
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Susan B Powell
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA
| | - Arthur L Brody
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA
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9
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Zatcepin A, Heindl S, Schillinger U, Kaiser L, Lindner S, Bartenstein P, Kopczak A, Liesz A, Brendel M, Ziegler SI. Reduced Acquisition Time [18F]GE-180 PET Scanning Protocol Replaces Gold-Standard Dynamic Acquisition in a Mouse Ischemic Stroke Model. Front Med (Lausanne) 2022; 9:830020. [PMID: 35223925 PMCID: PMC8866959 DOI: 10.3389/fmed.2022.830020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/17/2022] [Indexed: 02/04/2023] Open
Abstract
AimUnderstanding neuroinflammation after acute ischemic stroke is a crucial step on the way to an individualized post-stroke treatment. Microglia activation, an essential part of neuroinflammation, can be assessed using [18F]GE-180 18 kDa translocator protein positron emission tomography (TSPO-PET). However, the commonly used 60–90 min post-injection (p.i.) time window was not yet proven to be suitable for post-stroke neuroinflammation assessment. In this study, we compare semi-quantitative estimates derived from late time frames to quantitative estimates calculated using a full 0–90 min dynamic scan in a mouse photothrombotic stroke (PT) model.Materials and MethodsSix mice after PT and six sham mice were included in the study. For a half of the mice, we acquired four serial 0–90 min scans per mouse (analysis cohort) and calculated standardized uptake value ratios (SUVRs; cerebellar reference) for the PT volume of interest (VOI) in five late 10 min time frames as well as distribution volume ratios (DVRs) for the same VOI. We compared late static 10 min SUVRs and the 60–90 min time frame of the analysis cohort to the corresponding DVRs by linear fitting. The other half of the animals received a static 60–90 min scan and was used as a validation cohort. We extrapolated DVRs by using the static 60–90 min p.i. time window, which were compared to the DVRs of the analysis cohort.ResultsWe found high linear correlations between SUVRs and DVRs in the analysis cohort for all studied 10 min time frames, while the fits of the 60–70, 70–80, and 80–90 min p.i. time frames were the ones closest to the line of identity. For the 60–90 min time window, we observed an excellent linear correlation between SUVR and DVR regardless of the phenotype (PT vs. sham). The extrapolated DVRs of the validation cohort were not significantly different from the DVRs of the analysis group.ConclusionSimplified quantification by a reference tissue ratio of the late 60–90 min p.i. [18F]GE-180 PET image can replace full quantification of a dynamic scan for assessment of microglial activation in the mouse PT model.
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Affiliation(s)
- Artem Zatcepin
- Department of Nuclear Medicine, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- *Correspondence: Artem Zatcepin
| | - Steffanie Heindl
- Institute for Stroke and Dementia Research, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Institute for Stroke and Dementia Research, Munich, Germany
| | - Ulrike Schillinger
- Institute for Stroke and Dementia Research, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Institute for Stroke and Dementia Research, Munich, Germany
| | - Lena Kaiser
- Department of Nuclear Medicine, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Anna Kopczak
- Institute for Stroke and Dementia Research, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Institute for Stroke and Dementia Research, Munich, Germany
| | - Arthur Liesz
- Institute for Stroke and Dementia Research, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Institute for Stroke and Dementia Research, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sibylle I. Ziegler
- Department of Nuclear Medicine, University Hospital of Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
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10
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Yongyue Z, Yang S, Li Z, Rongjin Z, Shumin W. Functional Brain Imaging Based on the Neurovascular Unit for Evaluating Neural Networks after Strok. ADVANCED ULTRASOUND IN DIAGNOSIS AND THERAPY 2022. [DOI: 10.37015/audt.2022.210033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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11
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Ni R. Positron Emission Tomography in Animal Models of Alzheimer's Disease Amyloidosis: Translational Implications. Pharmaceuticals (Basel) 2021; 14:1179. [PMID: 34832961 PMCID: PMC8623863 DOI: 10.3390/ph14111179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 12/30/2022] Open
Abstract
Animal models of Alzheimer's disease amyloidosis that recapitulate cerebral amyloid-beta pathology have been widely used in preclinical research and have greatly enabled the mechanistic understanding of Alzheimer's disease and the development of therapeutics. Comprehensive deep phenotyping of the pathophysiological and biochemical features in these animal models is essential. Recent advances in positron emission tomography have allowed the non-invasive visualization of the alterations in the brain of animal models and in patients with Alzheimer's disease. These tools have facilitated our understanding of disease mechanisms and provided longitudinal monitoring of treatment effects in animal models of Alzheimer's disease amyloidosis. In this review, we focus on recent positron emission tomography studies of cerebral amyloid-beta accumulation, hypoglucose metabolism, synaptic and neurotransmitter receptor deficits (cholinergic and glutamatergic system), blood-brain barrier impairment, and neuroinflammation (microgliosis and astrocytosis) in animal models of Alzheimer's disease amyloidosis. We further propose the emerging targets and tracers for reflecting the pathophysiological changes and discuss outstanding challenges in disease animal models and future outlook in the on-chip characterization of imaging biomarkers towards clinical translation.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, ETH & University of Zurich, 8093 Zurich, Switzerland;
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
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12
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Direct Comparison of [ 18F]F-DPA with [ 18F]DPA-714 and [ 11C]PBR28 for Neuroinflammation Imaging in the same Alzheimer's Disease Model Mice and Healthy Controls. Mol Imaging Biol 2021; 24:157-166. [PMID: 34542805 PMCID: PMC8760190 DOI: 10.1007/s11307-021-01646-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/22/2021] [Accepted: 08/23/2021] [Indexed: 11/02/2022]
Abstract
PURPOSE In this study we compared the recently developed TSPO tracer [18F]F-DPA, with [18F]DPA-714 and [11C]PBR28 by performing in vivo PET imaging on the same Alzheimer's disease mouse model APP/PS1-21 (TG) and wild-type (WT) mice with all three radiotracers. PROCEDURES To compare the radiotracer uptake, percentage of injected dose/mL (%ID/mL), standardized uptake value ratios to cerebellum (SUVRCB), and voxel-wise analyses were performed. RESULTS The peak uptake of [18F]F-DPA was higher than 4.3% ID/mL, while [18F]DPA-714 reached just over 3% ID/mL, and [11C]PBR28 was over 4% ID/mL in only one brain region in the WT mice. The peak/60-min uptake ratios of [18F]F-DPA were significantly higher (p < 0.001) than those of [18F]DPA-714 and [11C]PBR28. The differences in [18F]F-DPA SUVRCB between WT and TG mice were highly significant (p < 0.001) in the three studied time periods after injection. [18F]DPA-714 uptake was significantly higher in TG mice starting in the 20-40-min timeframe and increased thereafter, whereas [11C]PBR28 uptake became significant at 10-20 min (p < 0.05). The voxel-wise analysis confirmed the differences between the radiotracers. CONCLUSIONS [18F]F-DPA displays higher brain uptake, higher TG-to-WT SUVRCB ratios, and faster clearance than [18F]DPA-714 and [11C]PBR28, and could prove useful for detecting low levels of inflammation and allow for shorter dynamic PET scans.
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13
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Zhou R, Ji B, Kong Y, Qin L, Ren W, Guan Y, Ni R. PET Imaging of Neuroinflammation in Alzheimer's Disease. Front Immunol 2021; 12:739130. [PMID: 34603323 PMCID: PMC8481830 DOI: 10.3389/fimmu.2021.739130] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 08/27/2021] [Indexed: 12/15/2022] Open
Abstract
Neuroinflammation play an important role in Alzheimer's disease pathogenesis. Advances in molecular imaging using positron emission tomography have provided insights into the time course of neuroinflammation and its relation with Alzheimer's disease central pathologies in patients and in animal disease models. Recent single-cell sequencing and transcriptomics indicate dynamic disease-associated microglia and astrocyte profiles in Alzheimer's disease. Mitochondrial 18-kDa translocator protein is the most widely investigated target for neuroinflammation imaging. New generation of translocator protein tracers with improved performance have been developed and evaluated along with tau and amyloid imaging for assessing the disease progression in Alzheimer's disease continuum. Given that translocator protein is not exclusively expressed in glia, alternative targets are under rapid development, such as monoamine oxidase B, matrix metalloproteinases, colony-stimulating factor 1 receptor, imidazoline-2 binding sites, cyclooxygenase, cannabinoid-2 receptor, purinergic P2X7 receptor, P2Y12 receptor, the fractalkine receptor, triggering receptor expressed on myeloid cells 2, and receptor for advanced glycation end products. Promising targets should demonstrate a higher specificity for cellular locations with exclusive expression in microglia or astrocyte and activation status (pro- or anti-inflammatory) with highly specific ligand to enable in vivo brain imaging. In this review, we summarised recent advances in the development of neuroinflammation imaging tracers and provided an outlook for promising targets in the future.
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Affiliation(s)
- Rong Zhou
- Department of Nephrology, Yangpu Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Bin Ji
- Department of Radiopharmacy and Molecular Imaging, School of Pharmacy, Fudan University, Shanghai, China
| | - Yanyan Kong
- Positron Emission Tomography (PET) Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Limei Qin
- Inner Mongolia Baicaotang Qin Chinese Mongolia Hospital, Hohhot, China
| | - Wuwei Ren
- School of Information Science and Technology, Shanghaitech University, Shanghai, China
| | - Yihui Guan
- Positron Emission Tomography (PET) Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, University of Zurich & Eidgenössische Technische Hochschule Zürich (ETH Zurich), Zurich, Switzerland
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14
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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] [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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15
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Zhang L, Hu K, Shao T, Hou L, Zhang S, Ye W, Josephson L, Meyer JH, Zhang MR, Vasdev N, Wang J, Xu H, Wang L, Liang SH. Recent developments on PET radiotracers for TSPO and their applications in neuroimaging. Acta Pharm Sin B 2021; 11:373-393. [PMID: 33643818 PMCID: PMC7893127 DOI: 10.1016/j.apsb.2020.08.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022] Open
Abstract
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is predominately localized to the outer mitochondrial membrane in steroidogenic cells. Brain TSPO expression is relatively low under physiological conditions, but is upregulated in response to glial cell activation. As the primary index of neuroinflammation, TSPO is implicated in the pathogenesis and progression of numerous neuropsychiatric disorders and neurodegenerative diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), major depressive disorder (MDD) and obsessive compulsive disorder (OCD). In this context, numerous TSPO-targeted positron emission tomography (PET) tracers have been developed. Among them, several radioligands have advanced to clinical research studies. In this review, we will overview the recent development of TSPO PET tracers, focusing on the radioligand design, radioisotope labeling, pharmacokinetics, and PET imaging evaluation. Additionally, we will consider current limitations, as well as translational potential for future application of TSPO radiopharmaceuticals. This review aims to not only present the challenges in current TSPO PET imaging, but to also provide a new perspective on TSPO targeted PET tracer discovery efforts. Addressing these challenges will facilitate the translation of TSPO in clinical studies of neuroinflammation associated with central nervous system diseases.
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Key Words
- AD, Alzheimer's disease
- ALS, amyotrophic lateral sclerosis
- AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid
- ANT, adenine nucleotide transporter
- Am, molar activities
- BBB, blood‒brain barrier
- BMSC, bone marrow stromal cells
- BP, binding potential
- BPND, non-displaceable binding potential
- BcTSPO, Bacillus cereus TSPO
- CBD, corticobasal degeneration
- CNS disorders
- CNS, central nervous system
- CRAC, cholesterol recognition amino acid consensus sequence
- DLB, Lewy body dementias
- EP, epilepsy
- FTD, frontotemporal dementia
- HAB, high-affinity binding
- HD, Huntington's disease
- HSE, herpes simplex encephalitis
- IMM, inner mitochondrial membrane
- KA, kainic acid
- LAB, low-affinity binding
- LPS, lipopolysaccharide
- MAB, mixed-affinity binding
- MAO-B, monoamine oxidase B
- MCI, mild cognitive impairment
- MDD, major depressive disorder
- MMSE, mini-mental state examination
- MRI, magnetic resonance imaging
- MS, multiple sclerosis
- MSA, multiple system atrophy
- Microglial activation
- NAA/Cr, N-acetylaspartate/creatine
- Neuroinflammation
- OCD, obsessive compulsive disorder
- OMM, outer mitochondrial membrane
- P2X7R, purinergic receptor P2X7
- PAP7, RIa-associated protein
- PBR, peripheral benzodiazepine receptor
- PCA, posterior cortical atrophy
- PD, Parkinson's disease
- PDD, PD dementia
- PET, positron emission tomography
- PKA, protein kinase A
- PRAX-1, PBR-associated protein 1
- PSP, progressive supranuclear palsy
- Positron emission tomography (PET)
- PpIX, protoporphyrin IX
- QA, quinolinic acid
- RCYs, radiochemical yields
- ROS, reactive oxygen species
- RRMS, relapsing remitting multiple sclerosis
- SA, specific activity
- SAH, subarachnoid hemorrhage
- SAR, structure–activity relationship
- SCIDY, spirocyclic iodonium ylide
- SNL, selective neuronal loss
- SNR, signal to noise ratio
- SUV, standard uptake volume
- SUVR, standard uptake volume ratio
- TBAH, tetrabutyl ammonium hydroxide
- TBI, traumatic brain injury
- TLE, temporal lobe epilepsy
- TSPO
- TSPO, translocator protein
- VDAC, voltage-dependent anion channel
- VT, distribution volume
- d.c. RCYs, decay-corrected radiochemical yields
- dMCAO, distal middle cerebral artery occlusion
- fP, plasma free fraction
- n.d.c. RCYs, non-decay-corrected radiochemical yields
- p.i., post-injection
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Kagitani-Shimono K, Kato H, Kuwayama R, Tominaga K, Nabatame S, Kishima H, Hatazawa J, Taniike M. Clinical evaluation of neuroinflammation in child-onset focal epilepsy: a translocator protein PET study. J Neuroinflammation 2021; 18:8. [PMID: 33407581 PMCID: PMC7789379 DOI: 10.1186/s12974-020-02055-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/09/2020] [Indexed: 01/17/2023] Open
Abstract
Background Neuroinflammation is associated with various chronic neurological diseases, including epilepsy; however, neuroimaging approaches for visualizing neuroinflammation have not been used in the clinical routine yet. In this study, we used the translocator protein positron emission tomography (PET) with [11C] DPA713 to investigate neuroinflammation in the epileptogenic zone in patients with child-onset focal epilepsy. Methods Patients with intractable focal epilepsy were recruited at the Epilepsy Center of Osaka University; those who were taking any immunosuppressants or steroids were excluded. PET images were acquired for 60 min after intravenous administration of [11C] DPA713. The PET image of [11C] DPA713 was co-registered to individual’s magnetic resonance imaging (MRI), and the standardized uptake value ratio (SUVr) in regions of interest, which were created in non-lesions and lesions, was calculated using the cerebellum as a pseudo-reference region. In the case of epilepsy surgery, the correlation between SUVr in lesions and pathological findings was analyzed. Results Twenty-seven patients (mean age: 11.3 ± 6.2 years, male/female: 17/10) were included in this study. Of these, 85.1% showed increased uptake of [11C] DPA713 in the focal epileptic lesion. Three patients showed epileptic spasms, suggesting partial seizure onset, and all 18 patients with abnormal lesions on MRI were similarly highlighted by significant uptake of [11C] DPA713. DPA713-positive patients had a broad range of etiologies, including focal cortical dysplasia, tumors, infarction, and hippocampal sclerosis. Five out of nine MRI-negative patients showed abnormal [11C] DPA713 uptake. The SUVr of [11C] DPA713 in lesions was significantly higher than that in non-lesions. In seven patients who underwent epilepsy surgery, increased [11C] DPA713 uptake was associated with microglial activation. Conclusions This study indicates that [11C] DPA713 uptake has valuable sensitivity in the identification of epileptic foci in child-onset focal epilepsy, and inflammation is implicated in the pathophysiology in the epileptic foci caused by various etiologies. Further research is required to establish diagnostic tools for identifying focal epileptogenic zones. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-020-02055-1.
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Affiliation(s)
- Kuriko Kagitani-Shimono
- Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan. .,Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan. .,Epilepsy Center, Osaka University Hospital, Suita, Japan.
| | - Hiroki Kato
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Ryoko Kuwayama
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan.,Epilepsy Center, Osaka University Hospital, Suita, Japan
| | - Koji Tominaga
- Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.,Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan.,Epilepsy Center, Osaka University Hospital, Suita, Japan
| | - Shin Nabatame
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan.,Epilepsy Center, Osaka University Hospital, Suita, Japan
| | - Haruhiko Kishima
- Epilepsy Center, Osaka University Hospital, Suita, Japan.,Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan.,Department of Quantum Cancer Therapy Research Center for Nuclear Physics, Osaka University, Suita, Japan
| | - Masako Taniike
- Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.,Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan
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18
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Rivière G, Jaipuria G, Andreas LB, Leonov A, Giller K, Becker S, Zweckstetter M. Membrane-embedded TSPO: an NMR view. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 50:173-180. [PMID: 33354729 PMCID: PMC8071791 DOI: 10.1007/s00249-020-01487-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/19/2020] [Accepted: 11/26/2020] [Indexed: 12/21/2022]
Abstract
Translocator Protein (18 kDa) (TSPO) is a mitochondrial transmembrane protein commonly used as a biomarker for neuroinflammation and is also a potential therapeutic target in neurodegenerative diseases. Despite intensive research efforts, the function of TSPO is still largely enigmatic. Deciphering TSPO structure in the native lipid environment is essential to gain insight into its cellular activities and to design improved diagnostic and therapeutic ligands. Here, we discuss the influence of lipid composition on the structure of mammalian TSPO embedded into lipid bilayers on the basis of solid-state NMR experiments. We further highlight that cholesterol can influence both the tertiary and quaternary TSPO structure and also influence TSPO localization in mitochondria-associated endoplasmic reticulum membranes.
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Affiliation(s)
- Gwladys Rivière
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Garima Jaipuria
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Andrei Leonov
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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19
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Al-Khishman NU, Qi Q, Roseborough AD, Levit A, Allman BL, Anazodo UC, Fox MS, Whitehead SN, Thiessen JD. TSPO PET detects acute neuroinflammation but not diffuse chronically activated MHCII microglia in the rat. EJNMMI Res 2020; 10:113. [PMID: 32990808 PMCID: PMC7524910 DOI: 10.1186/s13550-020-00699-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/11/2020] [Indexed: 12/19/2022] Open
Abstract
Background Accurate and sensitive imaging biomarkers are required to study the progression of white matter (WM) inflammation in neurodegenerative diseases. Radioligands targeting the translocator protein (TSPO) are considered sensitive indicators of neuroinflammation, but it is not clear how well the expression of TSPO coincides with major histocompatibility complex class II (MHCII) molecules in WM. This study aimed to test the ability of TSPO to detect activated WM microglia that are immunohistochemically positive for MHCII in rat models of prodromal Alzheimer’s disease and acute subcortical stroke. Methods Fischer 344 wild-type (n = 12) and TgAPP21 (n = 11) rats were imaged with [18F]FEPPA PET and MRI to investigate TSPO tracer uptake in the corpus callosum, a WM region known to have high levels of MHCII activated microglia in TgAPP21 rats. Wild-type rats subsequently received an endothelin-1 (ET1) subcortical stroke and were imaged at days 7 and 28 post-stroke before immunohistochemistry of TSPO, GFAP, iNOS, and the MHCII rat antigen, OX6. Results [18F]FEPPA PET was not significantly affected by genotype in WM and only detected increases near the ET1 infarct (P = 0.033, infarct/cerebellum uptake ratio: baseline = 0.94 ± 0.16; day 7 = 2.10 ± 0.78; day 28 = 1.77 ± 0.35). Immunohistochemistry confirmed that only the infarct (TSPO cells/mm2: day 7 = 555 ± 181; day 28 = 307 ± 153) and WM that is proximal to the infarct had TSPO expression (TSPO cells/mm2: day 7 = 113 ± 93; day 28 = 5 ± 7). TSPO and iNOS were not able to detect the chronic WM microglial activation that was detected with MHCII in the contralateral corpus callosum (day 28 OX6% area: saline = 0.62 ± 0.38; stroke = 4.30 ± 2.83; P = .029). Conclusion TSPO was only expressed in the stroke-induced insult and proximal tissue and therefore was unable to detect remote and non-insult-related chronically activated microglia overexpressing MHCII in WM. This suggests that research in neuroinflammation, particularly in the WM, would benefit from MHCII-sensitive radiotracers.
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Affiliation(s)
- Nassir U Al-Khishman
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Lawson Health Research Institute, B5-003a, 268 Grosvenor St, Stn. B, P.O. Box 5777, London, ON, N6A 4V2, Canada
| | - Qi Qi
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Lawson Health Research Institute, B5-003a, 268 Grosvenor St, Stn. B, P.O. Box 5777, London, ON, N6A 4V2, Canada
| | - Austyn D Roseborough
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Alexander Levit
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Brian L Allman
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Udunna C Anazodo
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Research Centre for Studies in Aging, McGill University, Montreal, QC, Canada
| | - Matthew S Fox
- Department of Physics and Astronomy, Western University, London, ON, Canada.,Lawson Health Research Institute, B5-003a, 268 Grosvenor St, Stn. B, P.O. Box 5777, London, ON, N6A 4V2, Canada
| | - Shawn N Whitehead
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Jonathan D Thiessen
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,Lawson Health Research Institute, B5-003a, 268 Grosvenor St, Stn. B, P.O. Box 5777, London, ON, N6A 4V2, Canada.
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20
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Bengel FM, Hermanns N, Thackeray JT. Radionuclide Imaging of the Molecular Mechanisms Linking Heart and Brain in Ischemic Syndromes. Circ Cardiovasc Imaging 2020; 13:e011303. [DOI: 10.1161/circimaging.120.011303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
For the heart and the brain, clinical observations suggest that an acute ischemic event experienced by one organ is associated with an increased risk for future acute events and chronic dysfunction of the reciprocal organ. Beyond atherosclerosis as a common systemic disease, various molecular mechanisms are thought to be involved in this interaction. Molecular-targeted nuclear imaging may identify the contribution of factors, such as the neurohumoral, circulatory, or especially the immune system, by combining specific radiotracers with whole-body acquisition and global as well as regional multiorgan analysis. This may be integrated with complementary functional imaging markers and systemic biomarkers for comprehensive network interrogation. Such systems-based strategies go beyond the traditional organ-centered approach and provide novel mechanistic insights, information about temporal dynamics, and a foundation for future interventions aiming at optimal preservation of function of both organs.
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Affiliation(s)
- Frank M. Bengel
- Department of Nuclear Medicine, Hannover Medical School, Germany
| | - Nele Hermanns
- Department of Nuclear Medicine, Hannover Medical School, Germany
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21
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Barca C, Foray C, Hermann S, Döring C, Schäfers M, Jacobs AH, Zinnhardt B. Characterization of the inflammatory post-ischemic tissue by full volumetric analysis of a multimodal imaging dataset. Neuroimage 2020; 222:117217. [PMID: 32745676 DOI: 10.1016/j.neuroimage.2020.117217] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/29/2020] [Accepted: 07/27/2020] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION In vivo positron emission tomography (PET) and magnetic resonance imaging (MRI) support non-invasive assessment of the spatiotemporal expression of proteins of interest and functional/structural changes. Our work promotes the use of a volumetric analysis on multimodal imaging datasets to assess the spatio-temporal dynamics and interaction of two imaging biomarkers, with a special focus on two neuroinflammation-related biomarkers, the translocator protein (TSPO) and matrix metalloproteinases (MMPs), in the acute and chronic post-ischemic phase. AIM To improve our understating of the neuroinflammatory reaction and tissue heterogeneity during the post ischemic phase, we aimed (i) to assess the spatio-temporal distribution of two radiotracers, [18F]DPA-714 (TSPO) and [18F]BR-351 (MMPs), (ii) to investigate their spatial interaction, including exclusive and overlapping areas, and (iii) their relationship with the T2w-MRI ischemic lesion in a transient middle cerebral artery occlusion (tMCAo) mouse model using an atlas-based volumetric analysis. METHODS As described by Zinnhardt et al. (2015), a total of N = 30 C57BL/6 mice underwent [18F]DPA-714 and [18F]BR-351 PET-CT and subsequent MR imaging 24-48 h (n = 8), 7 ± 1 days (n = 8), 14 ± 1 days (n = 7), and 21 ± 1 days (n = 7) after 30 min transient middle cerebral artery occlusion (tMCAo). To further investigate the spatio-temporal distribution of [18F]DPA-714 and [18F]BR-351, an atlas-based ipsilesional volume of interest (VOI) was applied to co-registered PET-CT images and thresholded by the mean uptake + 2.5*standard deviation of a contralateral striatal control VOI. Mean lesion-to-contralateral ratios (L/C), volume extension (V in voxel), percentages of overlap and exclusive tracer uptake areas were determined. Both tracer volumes were also compared to the lesion extent depicted by T2w-MR imaging. RESULTS Both imaging biomarkers showed a constant small percentage of overlap across all time points (14.0 ± 14.2%). [18F]DPA-714 reached its maximum extent and uptake at day 14 post ischemia (V = 12,143 ± 6262 voxels, L/C = 2.32 ± 0.48). The majority of [18F]DPA-714 volume (82.4 ± 16.1%) was exclusive for [18F]DPA-714 and showed limited overlap with [18F]BR-351 and T2w-MRI lesion volumes. On the other hand, [18F]BR-351 reached its maximum extent already 24-48 h after tMCAo (V = 7279 ± 4518 voxels) and significantly decreased at day 14 (V = 1706 ± 1202 voxels). Focal spots of residual activity were still observed at day 21 post ischemia (L/C = 2.10 ± 0.37). The majority of [18F]BR-351 volume was exclusive for [18F]BR-351 (81.50 ± 25.07%) at 24-48 h and showed 64.84 ± 28.29% of overlap with [18F]DPA-714 from day 14 post ischemia while only 9.28 ± 13.45% of the [18F]BR-351 volume were overlapping the T2w-MRI lesion. The percentage of exclusive area of [18F]DPA-714 and [18F]BR-351 uptakes regarding T2w-MR lesion increased over time, suggesting that TSPO and MMPs are mostly localized in the peri‑infarct region at latter time points. CONCLUSION This study promotes the use of an unbiased volumetric analyses of multi-modal imaging data sets to improve the characterization of pathological tissue heterogeneity. This approach improves our understanding of (i) the dynamics of disease-related multi-modal imaging biomarkers, (ii) their spatiotemporal interactions and (iii) the post-ischemic tissue heterogeneity. Our results indicate acute MMPs activation after tMCAo preceding TSPO-dependent (micro-)gliosis. The spatial distribution of MMPs and gliosis is regionally independent with only minor (< 20%) overlapping areas in peri‑infarct regions.
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Affiliation(s)
- Cristina Barca
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany; PET Imaging in Drug Design and Development (PET3D), Münster, Germany.
| | - Claudia Foray
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany; PET Imaging in Drug Design and Development (PET3D), Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany; Immune Image, Innovative Medicines Initiative (IMI)
| | - Christian Döring
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany
| | - Michael Schäfers
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany; Immune Image, Innovative Medicines Initiative (IMI); Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany; PET Imaging in Drug Design and Development (PET3D), Münster, Germany; Imaging Neuroinflammation in Neurodegenerative Diseases (INMIND) EU FP7 consortium, Münster, Germany; Immune Image, Innovative Medicines Initiative (IMI); Department of Geriatrics, Johanniter Hospital, Bonn, Germany
| | - Bastian Zinnhardt
- European Institute for Molecular Imaging (EIMI), University of Münster, Münster, Germany; PET Imaging in Drug Design and Development (PET3D), Münster, Germany; Imaging Neuroinflammation in Neurodegenerative Diseases (INMIND) EU FP7 consortium, Münster, Germany; Immune Image, Innovative Medicines Initiative (IMI); Department of Nuclear Medicine, University Hospital Münster, Münster, Germany.
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22
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Jain P, Chaney AM, Carlson ML, Jackson IM, Rao A, James ML. Neuroinflammation PET Imaging: Current Opinion and Future Directions. J Nucl Med 2020; 61:1107-1112. [PMID: 32620705 DOI: 10.2967/jnumed.119.229443] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Neuroinflammation is a key pathologic hallmark of numerous neurologic diseases, however, its exact role in vivo is yet to be fully understood. PET imaging enables investigation, quantification, and tracking of different neuroinflammation biomarkers in living subjects longitudinally. One such biomarker that has been imaged extensively using PET is translocator protein 18 kDa (TSPO). Although imaging TSPO has yielded valuable clinical data linking neuroinflammation to various neurodegenerative diseases, considerable limitations of TSPO PET have prompted identification of other more cell-specific and functionally relevant biomarkers. This review analyzes the clinical potential of available and emerging PET biomarkers of innate and adaptive immune responses, with mention of exciting future directions for the field.
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Affiliation(s)
- Poorva Jain
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Aisling M Chaney
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Mackenzie L Carlson
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California.,Department of Bioengineering, Stanford University, Stanford, California; and
| | - Isaac M Jackson
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Anoushka Rao
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California
| | - Michelle L James
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California .,Department of Neurology and Neurological Sciences, Stanford University, Stanford, California
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23
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Yang AC, Stevens MY, Chen MB, Lee DP, Stähli D, Gate D, Contrepois K, Chen W, Iram T, Zhang L, Vest RT, Chaney A, Lehallier B, Olsson N, du Bois H, Hsieh R, Cropper HC, Berdnik D, Li L, Wang EY, Traber GM, Bertozzi CR, Luo J, Snyder MP, Elias JE, Quake SR, James ML, Wyss-Coray T. Physiological blood-brain transport is impaired with age by a shift in transcytosis. Nature 2020; 583:425-430. [PMID: 32612231 DOI: 10.1038/s41586-020-2453-z] [Citation(s) in RCA: 228] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 05/21/2020] [Indexed: 12/31/2022]
Abstract
The vascular interface of the brain, known as the blood-brain barrier (BBB), is understood to maintain brain function in part via its low transcellular permeability1-3. Yet, recent studies have demonstrated that brain ageing is sensitive to circulatory proteins4,5. Thus, it is unclear whether permeability to individually injected exogenous tracers-as is standard in BBB studies-fully represents blood-to-brain transport. Here we label hundreds of proteins constituting the mouse blood plasma proteome, and upon their systemic administration, study the BBB with its physiological ligand. We find that plasma proteins readily permeate the healthy brain parenchyma, with transport maintained by BBB-specific transcriptional programmes. Unlike IgG antibody, plasma protein uptake diminishes in the aged brain, driven by an age-related shift in transport from ligand-specific receptor-mediated to non-specific caveolar transcytosis. This age-related shift occurs alongside a specific loss of pericyte coverage. Pharmacological inhibition of the age-upregulated phosphatase ALPL, a predicted negative regulator of transport, enhances brain uptake of therapeutically relevant transferrin, transferrin receptor antibody and plasma. These findings reveal the extent of physiological protein transcytosis to the healthy brain, a mechanism of widespread BBB dysfunction with age and a strategy for enhanced drug delivery.
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Affiliation(s)
- Andrew C Yang
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA, USA.,ChEM-H, Stanford University, Stanford, CA, USA.,Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Marc Y Stevens
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle B Chen
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA, USA
| | - Davis P Lee
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Daniel Stähli
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - David Gate
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Kévin Contrepois
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Winnie Chen
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Tal Iram
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Ryan T Vest
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Department of Chemical Engineering, Stanford, CA, USA
| | - Aisling Chaney
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Benoit Lehallier
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Niclas Olsson
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA.,Calico Life Sciences LLC, South San Francisco, CA, USA
| | - Haley du Bois
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Ryan Hsieh
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Haley C Cropper
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Daniela Berdnik
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Lulin Li
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Elizabeth Y Wang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Gavin M Traber
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Carolyn R Bertozzi
- ChEM-H, Stanford University, Stanford, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Jian Luo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Veterans Administration Palo Alto Healthcare System, Palo Alto, CA, USA
| | - Michael P Snyder
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Stephen R Quake
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA, USA.,Chan Zuckerberg Biohub, Stanford, CA, USA
| | - Michelle L James
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
| | - Tony Wyss-Coray
- ChEM-H, Stanford University, Stanford, CA, USA. .,Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Chemistry, Stanford University, Stanford, CA, USA. .,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA. .,Paul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA, USA.
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24
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Letter to the Editor re: Confirmation of Specific Binding of the 18-kDa Translocator Protein (TSPO) Radioligand [ 18F]GE-180: a Blocking Study Using XBD173 in Multiple Sclerosis Normal Appearing White and Grey Matter. Mol Imaging Biol 2020; 22:10-12. [PMID: 31641965 DOI: 10.1007/s11307-019-01433-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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25
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Tomasella E, Falasco G, Urrutia L, Bechelli L, Padilla L, Gelman DM. Impaired brain glucose metabolism and presynaptic dopaminergic functioning in a mouse model of schizophrenia. EJNMMI Res 2020; 10:39. [PMID: 32303857 PMCID: PMC7165233 DOI: 10.1186/s13550-020-00629-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/07/2020] [Indexed: 12/22/2022] Open
Abstract
Background Schizophrenia is a disease diagnosed by visible signs and symptoms from late adolescence to early adulthood. The etiology of this disease remains unknown. An objective diagnostic approach is required. Here, we used a mouse model that shows schizophrenia-like phenotypes to study brain glucose metabolism and presynaptic dopaminergic functioning by positron emission tomography (PET) and immunohistochemistry. PET scannings were performed on mice after the administration of [18F]-FDG or [18F]-F-DOPA. Glucose metabolism was evaluated in basal conditions and after the induction of a hyperdopaminergic state. Results Mutant animals show reduced glucose metabolism in prefrontal cortex, amygdala, and nucleus reuniens under the hyperdopaminergic state. They also show reduced [18F]-F-DOPA uptake in prefrontal cortex, substantia nigra reticulata, raphe nucleus, and ventral striatum but increased [18F]-F-DOPA uptake in dorsal striatum. Mutant animals also show reduced tyrosine hydroxylase expression on midbrain neurons. Conclusions Dopamine D2 mutant animals show reduced glucose metabolism and impaired presynaptic dopaminergic functioning, in line with reports from human studies. This mouse line may be a valuable model of schizophrenia, useful to test novel tracers for PET scanning diagnostic.
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Affiliation(s)
- Eugenia Tomasella
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Vuelta de Obligado 2490, C1428ADN, Ciudad de Buenos Aires, Argentina
| | - German Falasco
- Fleni, Centro de Imágenes Moleculares (CIM), Laboratorio de Imágenes Preclínicas, Buenos Aires, Argentina
| | - Leandro Urrutia
- Fleni, Centro de Imágenes Moleculares (CIM), Laboratorio de Imágenes Preclínicas, Buenos Aires, Argentina
| | - Lucila Bechelli
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Vuelta de Obligado 2490, C1428ADN, Ciudad de Buenos Aires, Argentina
| | - Lucia Padilla
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Vuelta de Obligado 2490, C1428ADN, Ciudad de Buenos Aires, Argentina
| | - Diego M Gelman
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Vuelta de Obligado 2490, C1428ADN, Ciudad de Buenos Aires, Argentina.
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26
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Dimitrova-Shumkovska J, Krstanoski L, Veenman L. Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update. Cells 2020; 9:cells9040870. [PMID: 32252470 PMCID: PMC7226777 DOI: 10.3390/cells9040870] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/30/2020] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation and cell death are among the common symptoms of many central nervous system diseases and injuries. Neuroinflammation and programmed cell death of the various cell types in the brain appear to be part of these disorders, and characteristic for each cell type, including neurons and glia cells. Concerning the effects of 18-kDa translocator protein (TSPO) on glial activation, as well as being associated with neuronal cell death, as a response mechanism to oxidative stress, the changes of its expression assayed with the aid of TSPO-specific positron emission tomography (PET) tracers' uptake could also offer evidence for following the pathogenesis of these disorders. This could potentially increase the number of diagnostic tests to accurately establish the stadium and development of the disease in question. Nonetheless, the differences in results regarding TSPO PET signals of first and second generations of tracers measured in patients with neurological disorders versus healthy controls indicate that we still have to understand more regarding TSPO characteristics. Expanding on investigations regarding the neuroprotective and healing effects of TSPO ligands could also contribute to a better understanding of the therapeutic potential of TSPO activity for brain damage due to brain injury and disease. Studies so far have directed attention to the effects on neurons and glia, and processes, such as death, inflammation, and regeneration. It is definitely worthwhile to drive such studies forward. From recent research it also appears that TSPO ligands, such as PK11195, Etifoxine, Emapunil, and 2-Cl-MGV-1, demonstrate the potential of targeting TSPO for treatments of brain diseases and disorders.
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Affiliation(s)
- Jasmina Dimitrova-Shumkovska
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
- Correspondence: (J.D.-S.); (L.V.)
| | - Ljupcho Krstanoski
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
| | - Leo Veenman
- Technion-Israel Institute of Technology, Faculty of Medicine, Rappaport Institute of Medical Research, 1 Efron Street, P.O. Box 9697, Haifa 31096, Israel
- Correspondence: (J.D.-S.); (L.V.)
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27
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Longitudinal mouse-PET imaging: a reliable method for estimating binding parameters without a reference region or blood sampling. Eur J Nucl Med Mol Imaging 2020; 47:2589-2601. [PMID: 32211931 PMCID: PMC7515949 DOI: 10.1007/s00259-020-04755-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 03/03/2020] [Indexed: 01/06/2023]
Abstract
Abstract Longitudinal mouse PET imaging is becoming increasingly popular due to the large number of transgenic and disease models available but faces challenges. These challenges are related to the small size of the mouse brain and the limited spatial resolution of microPET scanners, along with the small blood volume making arterial blood sampling challenging and impossible for longitudinal studies. The ability to extract an input function directly from the image would be useful for quantification in longitudinal small animal studies where there is no true reference region available such as TSPO imaging. Methods Using dynamic, whole-body 18F-DPA-714 PET scans (60 min) in a mouse model of hippocampal sclerosis, we applied a factor analysis (FA) approach to extract an image-derived input function (IDIF). This mouse-specific IDIF was then used for 4D-resolution recovery and denoising (4D-RRD) that outputs a dynamic image with better spatial resolution and noise properties, and a map of the total volume of distribution (VT) was obtained using a basis function approach in a total of 9 mice with 4 longitudinal PET scans each. We also calculated percent injected dose (%ID) with and without 4D-RRD. The VT and %ID parameters were compared to quantified ex vivo autoradiography using regional correlations of the specific binding from autoradiography against VT and %ID parameters. Results The peaks of the IDIFs were strongly correlated with the injected dose (Pearson R = 0.79). The regional correlations between the %ID estimates and autoradiography were R = 0.53 without 4D-RRD and 0.72 with 4D-RRD over all mice and scans. The regional correlations between the VT estimates and autoradiography were R = 0.66 without 4D-RRD and 0.79 with application of 4D-RRD over all mice and scans. Conclusion We present a FA approach for IDIF extraction which is robust, reproducible and can be used in quantification methods for resolution recovery, denoising and parameter estimation. We demonstrated that the proposed quantification method yields parameter estimates closer to ex vivo measurements than semi-quantitative methods such as %ID and is immune to tracer binding in tissue unlike reference tissue methods. This approach allows for accurate quantification in longitudinal PET studies in mice while avoiding repeated blood sampling. Electronic supplementary material The online version of this article (10.1007/s00259-020-04755-5) contains supplementary material, which is available to authorized users.
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Wang Z, Mascarenhas C, Jia X. Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments. Transl Stroke Res 2020; 11:628-642. [PMID: 31939060 DOI: 10.1007/s12975-019-00765-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/22/2019] [Accepted: 12/04/2019] [Indexed: 12/19/2022]
Abstract
Positron emission tomography (PET) is widely used in clinical and animal studies, along with the development of diverse tracers. The biochemical characteristics of PET tracers may help uncover the pathophysiological consequences of cardiac arrest (CA) and ischemic stroke, which include cerebral ischemia and reperfusion, depletion of oxygen and glucose, and neuroinflammation. PubMed was searched for studies of the application of PET for "cardiac arrest," "ischemic stroke," and "targeted temperature management." Available studies were included and classified according to the biochemical properties involved and metabolic processes of PET tracers, and were summarized. The mechanisms of ischemic brain injuries were investigated by PET with various tracers to elucidate the pathological process from the initial decrease of cerebral blood flow (CBF) to the subsequent abnormalities in energy and oxygen metabolism, to the monitoring of inflammation. In general, the trends of cerebral blood flow and oxygen metabolism after ischemic attack are not unidirectional but closely related to the time point of injury and recovery. Glucose metabolism after injury showed significant differences in different brain regions whereas global cerebral metabolic rate of glucose (CMRglc) declined. PET monitoring of neuroinflammation shows comparable efficacy to immunostaining. The technology of PET targeting in brain metabolism and the development of tracers provide new tools to track and evaluate the brain's pathological changes after ischemic brain injury. Despite no existing evidence for an available PET-based prediction method, discoveries of new tracers are expected to provide more possibilities for the whole field.
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Affiliation(s)
- Zhuoran Wang
- Department of Critical Care Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 43007, China.,Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Conrad Mascarenhas
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA. .,Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Xu J, Sun J, Perrin RJ, Mach RH, Bales KR, Morris JC, Benzinger TLS, Holtzman DM. Translocator protein in late stage Alzheimer's disease and Dementia with Lewy bodies brains. Ann Clin Transl Neurol 2019; 6:1423-1434. [PMID: 31402620 PMCID: PMC6689696 DOI: 10.1002/acn3.50837] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE Increased translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), in glial cells of the brain has been used as a neuroinflammation marker in the early and middle stages of neurodegenerative diseases, such as Alzheimer's disease (AD) and Dementia with Lewy Bodies (DLB). In this study, we investigated the changes in TSPO density with respect to late stage AD and DLB. METHODS TSPO density was measured in multiple regions of postmortem human brains in 20 different cases: seven late stage AD cases (Braak amyloid average: C; Braak tangle average: VI; Aged 74-88, mean: 83 ± 5 years), five DLB cases (Braak amyloid average: C; Braak tangle average: V; Aged 79-91, mean: 84 ± 4 years), and eight age-matched normal control cases (3 males, 5 females: aged 77-92 years; mean: 87 ± 6 years). Measurements were taken by quantitative autoradiography using [3 H]PK11195 and [3 H]PBR28. RESULTS No significant changes were found in TSPO density of the frontal cortex, striatum, thalamus, or red nucleus of the AD and DLB brains. A significant reduction in TSPO density was found in the substantia nigra (SN) of the AD and DLB brains compared to that of age-matched healthy controls. INTERPRETATION This distinct pattern of TSPO density change in late stage AD and DLB cases may imply the occurrence of microglia dystrophy in late stage neurodegeneration. Furthermore, TSPO may not only be a microglia activation marker in early stage AD and DLB, but TSPO may also be used to monitor microglia dysfunction in the late stage of these diseases.
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Affiliation(s)
- Jinbin Xu
- Department of RadiologyWashington University School of Medicine510 S. Kingshighway BlvdSt. LouisMissouri63110
| | - Jianjun Sun
- Department of RadiologyWashington University School of Medicine510 S. Kingshighway BlvdSt. LouisMissouri63110
| | - Richard J. Perrin
- Department of Pathology & ImmunologyWashington University School of Medicine510 S. Kingshighway BlvdSt. LouisMissouri63110
| | - Robert H. Mach
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | | | - John C. Morris
- Department of NeurologyWashington University School of Medicine510 S. Kingshighway BlvdSt. LouisMissouri63110
| | - Tammie L. S. Benzinger
- Department of RadiologyWashington University School of Medicine510 S. Kingshighway BlvdSt. LouisMissouri63110
| | - David M. Holtzman
- Department of NeurologyWashington University School of Medicine510 S. Kingshighway BlvdSt. LouisMissouri63110
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Shi K, Tian DC, Li ZG, Ducruet AF, Lawton MT, Shi FD. Global brain inflammation in stroke. Lancet Neurol 2019; 18:1058-1066. [PMID: 31296369 DOI: 10.1016/s1474-4422(19)30078-x] [Citation(s) in RCA: 418] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/11/2019] [Accepted: 02/11/2019] [Indexed: 01/21/2023]
Abstract
Stroke, including acute ischaemic stroke and intracerebral haemorrhage, results in neuronal cell death and the release of factors such as damage-associated molecular patterns (DAMPs) that elicit localised inflammation in the injured brain region. Such focal brain inflammation aggravates secondary brain injury by exacerbating blood-brain barrier damage, microvascular failure, brain oedema, oxidative stress, and by directly inducing neuronal cell death. In addition to inflammation localised to the injured brain region, a growing body of evidence suggests that inflammatory responses after a stroke occur and persist throughout the entire brain. Global brain inflammation might continuously shape the evolving pathology after a stroke and affect the patients' long-term neurological outcome. Future efforts towards understanding the mechanisms governing the emergence of so-called global brain inflammation would facilitate modulation of this inflammation as a potential therapeutic strategy for stroke.
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Affiliation(s)
- Kaibin Shi
- Tianjin Medical University General Hospital, Tianjin, China; Department of Neurology, and Department of Neurosurgery, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - De-Cai Tian
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Tianjin Medical University General Hospital, Tianjin, China
| | - Zhi-Guo Li
- Tianjin Medical University General Hospital, Tianjin, China
| | - Andrew F Ducruet
- Department of Neurology, and Department of Neurosurgery, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Michael T Lawton
- Department of Neurology, and Department of Neurosurgery, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Fu-Dong Shi
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Tianjin Medical University General Hospital, Tianjin, China.
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Recent Developments in TSPO PET Imaging as A Biomarker of Neuroinflammation in Neurodegenerative Disorders. Int J Mol Sci 2019; 20:ijms20133161. [PMID: 31261683 PMCID: PMC6650818 DOI: 10.3390/ijms20133161] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/20/2019] [Accepted: 05/20/2019] [Indexed: 12/12/2022] Open
Abstract
Neuroinflammation is an inflammatory response in the brain and spinal cord, which can involve the activation of microglia and astrocytes. It is a common feature of many central nervous system disorders, including a range of neurodegenerative disorders. An overlap between activated microglia, pro-inflammatory cytokines and translocator protein (TSPO) ligand binding was shown in early animal studies of neurodegeneration. These findings have been translated in clinical studies, where increases in TSPO positron emission tomography (PET) signal occur in disease-relevant areas across a broad spectrum of neurodegenerative diseases. While this supports the use of TSPO PET as a biomarker to monitor response in clinical trials of novel neurodegenerative therapeutics, the clinical utility of current TSPO PET radioligands has been hampered by the lack of high affinity binding to a prevalent form of polymorphic TSPO (A147T) compared to wild type TSPO. This review details recent developments in exploration of ligand-sensitivity to A147T TSPO that have yielded ligands with improved clinical utility. In addition to developing a non-discriminating TSPO ligand, the final frontier of TSPO biomarker research requires developing an understanding of the cellular and functional interpretation of the TSPO PET signal. Recent insights resulting from single cell analysis of microglial phenotypes are reviewed.
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Ghadery C, Best LA, Pavese N, Tai YF, Strafella AP. PET Evaluation of Microglial Activation in Non-neurodegenerative Brain Diseases. Curr Neurol Neurosci Rep 2019; 19:38. [PMID: 31139952 PMCID: PMC6538572 DOI: 10.1007/s11910-019-0951-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE OF THE REVIEW Microglial cell activation is an important component of neuroinflammation, and it is generally well accepted that chronic microglial activation is indicative of accumulating tissue damage in neurodegenerative conditions, particularly in the earlier stages of disease. Until recently, there has been less focus on the role of neuroinflammation in other forms of neurological and neuropsychiatric conditions. Through this review, we hope to demonstrate the important role TSPO PET imaging has played in illuminating the pivotal role of neuroinflammation and microglial activation underpinning these conditions. RECENT FINDINGS TSPO is an 18 kDa protein found on the outer membrane of mitochondria and can act as a marker of microglial activation using nuclear imaging. Through the development of radiopharmaceuticals targeting TSPO, researchers have been able to better characterise the spatial-temporal evolution of chronic neurological conditions, ranging from the focal autoimmune reactions seen in multiple sclerosis to the Wallerian degeneration at remote parts of the brain months following acute cerebral infarction. Development of novel techniques to investigate neuroinflammation within the central nervous system, for the purposes of diagnosis and therapeutics, has flourished over the past few decades. TSPO has proven itself a robust and sensitive biomarker of microglial activation and neuroimaging affords a minimally invasive technique to characterise neuroinflammatory processes in vivo.
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Affiliation(s)
- Christine Ghadery
- The Edmond J. Safra Program in Parkinson's Disease & Movement Disorder Unit, Toronto Western Hospital & Krembil Research Institute, University Health Network; Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
| | - Laura A Best
- Clinical Ageing Research Unit, Newcastle University, Campus for Ageing and Vitality, Westgate Road, Newcastle Upon Tyne, UK.
| | - Nicola Pavese
- Clinical Ageing Research Unit, Newcastle University, Campus for Ageing and Vitality, Westgate Road, Newcastle Upon Tyne, UK
- PET centre, University of Aarhus Denmark, Aarhus, Denmark
| | - Yen Foung Tai
- Imperial College London South Kensington Campus, London, UK
| | - Antonio P Strafella
- The Edmond J. Safra Program in Parkinson's Disease & Movement Disorder Unit, Toronto Western Hospital & Krembil Research Institute, University Health Network; Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
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Zanotti-Fregonara P, Veronese M, Pascual B, Rostomily RC, Turkheimer F, Masdeu JC. The validity of 18F-GE180 as a TSPO imaging agent. Eur J Nucl Med Mol Imaging 2019; 46:1205-1207. [PMID: 30656358 DOI: 10.1007/s00259-019-4268-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 01/07/2019] [Indexed: 01/23/2023]
Affiliation(s)
- Paolo Zanotti-Fregonara
- Nantz National Alzheimer Center and Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA.
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, Kings College London, London, UK
| | - Belen Pascual
- Nantz National Alzheimer Center and Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA
| | - Robert C Rostomily
- Department of Neurosurgery, Houston Methodist Hospital and Research Institute, Houston, TX, USA
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, Kings College London, London, UK
| | - Joseph C Masdeu
- Nantz National Alzheimer Center and Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA
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