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Shraim MA, Massé-Alarie H, Farrell MJ, Cavaleri R, Loggia ML, Hodges PW. Neuroinflammatory activation in sensory and motor regions of the cortex is related to sensorimotor function in individuals with low back pain maintained by nociplastic mechanisms: A preliminary proof-of-concept study. Eur J Pain 2024. [PMID: 39007713 DOI: 10.1002/ejp.2313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 06/26/2024] [Accepted: 06/30/2024] [Indexed: 07/16/2024]
Abstract
BACKGROUND Chronic pain involves communication between neural and immune systems. Recent data suggest localization of glial (brain immune cells) activation to the sensorimotor regions of the brain cortex (S1/M1) in chronic low back pain (LBP). As glia perform diverse functions that impact neural function, activation might contribute to sensorimotor changes, particularly in LBP maintained by increased nervous system sensitivity (i.e., nociplastic pain). This preliminary proof-of-concept study aimed to: (i) compare evidence of neuroinflammatory activation in S1/M1 between individuals with and without LBP (and between nociceptive and nociplastic LBP phenotypes), and (ii) evaluate relationships between neuroinflammatory activation and sensorimotor function. METHODS Simultaneous PET-fMRI measured neuroinflammatory activation in functionally defined S1/M1 in pain-free individuals (n = 8) and individuals with chronic LBP (n = 9; nociceptive: n = 4, nociplastic: n = 5). Regions of S1/M1 related to the back were identified using fMRI during motor tasks and thermal stimuli. Sensorimotor measures included single and paired-pulse transcranial magnetic stimulation (TMS) and quantitative sensory testing (QST). Sleep, depression, disability and pain questionnaires were administered. RESULTS Neuroinflammatory activation was greater in the lower back cortical representation of S1/M1 of the nociplastic LBP group than both nociceptive LBP and pain-free groups. Neuroinflammatory activation in S1/M1 was positively correlated with sensitivity to hot (r = 0.52) and cold (r = 0.55) pain stimuli, poor sleep, depression, disability and BMI, and negatively correlated with intracortical facilitation (r = -0.41). CONCLUSION This preliminary proof-of-concept study suggests that neuroinflammation in back regions of S1/M1 in individuals with nociplastic LBP could plausibly explain some characteristic features of this LBP phenotype. SIGNIFICANCE STATEMENT Neuroinflammatory activation localized to sensorimotor areas of the brain in individuals with nociplastic pain might contribute to changes in sensory and motor function and aspects of central sensitization. If cause-effect relationships are established in longitudinal studies, this may direct development of therapies that target neuroinflammatory activation.
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Affiliation(s)
- Muath A Shraim
- The University of Queensland, School of Health & Rehabilitation Sciences, St Lucia, Queensland, Australia
| | - Hugo Massé-Alarie
- The University of Queensland, School of Health & Rehabilitation Sciences, St Lucia, Queensland, Australia
- Centre Interdisciplinaire de Recherche en réadaptation et Integration Sociale (CIRRIS), Université Laval, Québec City, Québec, Canada
| | - Michael J Farrell
- Monash Biomedical Imaging, Monash University, Melbourne, Victoria, Australia
| | - Rocco Cavaleri
- Brain Stimulation and Rehabilitation Lab, Western Sydney University, School of Health Sciences, Sydney, New South Wales, Australia
| | - Marco L Loggia
- MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Paul W Hodges
- The University of Queensland, School of Health & Rehabilitation Sciences, St Lucia, Queensland, Australia
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Alagaratnam J, Thornhill JP, Fan Z, Vera JH, Underwood J, Hall R, Searle G, Owen D, Edison P, Fidler S, Winston A. Differences in neuroinflammation in people who started antiretroviral treatment during primary versus chronic HIV infection: an 18kDa Translocator protein (TSPO) positron emission tomography (PET) study. J Neurovirol 2024:10.1007/s13365-024-01200-3. [PMID: 38575831 DOI: 10.1007/s13365-024-01200-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/27/2024] [Accepted: 03/01/2024] [Indexed: 04/06/2024]
Abstract
Persistent inflammation is described in people with HIV (PWH) on antiretroviral treatment (ART). Early ART initiation is associated with reduced inflammation. We aimed to evaluate neuroinflammation, using translocator protein (TSPO) [11C]PBR28 PET neuroimaging in PWH who initiated ART during acute HIV (aPWH) versus chronic HIV infection (cPWH) versus a control population. This was a cross-sectional, observational study. All participants underwent [11C]PBR28 PET-CT neuroimaging. Using a two-tissue compartment model, total volume of distribution (VT) and distribution volume ratios (DVR) using cortical grey matter as a pseudo-reference region at 20 regions of interest (ROIs) were calculated. Differences in VT and DVR were compared between groups using the Kruskall-Wallis test. Seventeen neuro-asymptomatic male PWH on ART (9 aPWH, 8 cPWH) and 8 male control participants (CPs) were included. Median (interquartile range, IQR) age was 40 (30, 46), 44 (41, 47) and 21 (20, 25) years in aPWH, cPWH and CPs, respectively. Median (IQR) CD4 (cells/µL) and CD4:CD8 were 687 (652, 1014) and 1.37 (1.24, 1.42), and 700 (500, 720) and 0.67 (0.64, 0.82) in aPWH and cPWH, respectively. Overall, no significant difference in VT and DVR were observed between the three groups at any ROIs. cPWH demonstrated a trend towards higher mean VT compared with aPWH and CPs at most ROIs. No significant differences in neuroinflammation, using [11C]PBR28 binding as a proxy, were identified between cPWH, aPWH and CPs. A trend towards lower absolute [11C]PBR28 binding was seen amongst aPWH and CPs, suggesting early ART may mitigate neuroinflammation.
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Affiliation(s)
- Jasmini Alagaratnam
- Department of Sexual Health & HIV, Chelsea & Westminster Hospital NHS Foundation Trust, London, UK.
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK.
| | - John P Thornhill
- Blizard Institute, Barts & the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Zhen Fan
- Invicro, A Konica Minolta Company, London, UK
| | - Jaime H Vera
- Department of Global Health and Infection, Brighton and Sussex Medical School, London, UK
| | - Jonathan Underwood
- Division of Infection and Immunity, School of Medicine, Cardiff University, UHW Main Building, Heath Park, Cardiff, CF14 4XN, UK
| | - Rebecca Hall
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | | | - David Owen
- Department of Brain Sciences, Imperial College London, London, UK
| | - Paul Edison
- Department of Brain Sciences, Imperial College London, London, UK
| | - Sarah Fidler
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
- Department of Genitourinary Medicine & HIV, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Alan Winston
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
- Department of Genitourinary Medicine & HIV, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
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Ibrahim W, An J, Yang Y, Cosgrove KP, Matuskey D. Does seasonal variation affect the neuroimmune system? A retrospective [ 11C]PBR28 PET study in healthy individuals. Neurosci Lett 2024; 828:137766. [PMID: 38583505 PMCID: PMC11073647 DOI: 10.1016/j.neulet.2024.137766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/31/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024]
Abstract
INTRODUCTION The neuroimmune system performs a wide range of functions in the brain and the central nervous system. The microglial translocator protein (TSPO) has an established role as a cell marker in identification of the neuroimmune system. Previously, human studies have shown TSPO differences in neuropsychiatric disorders. Seasonal variability has also been demonstrated in multiple systems of healthy individuals. Therefore, in this study, we attempt to understand whether seasonal changes affect brain TSPO levels using [11C]PBR28 positron emission tomography (PET) imaging. METHODS 46 healthy subjects (mean age ± SD = 32.5 ± 10); sex (M/F) = 32/14)) underwent PET imaging with [11C]PBR28 in a retrospectively conducted analysis. All PET scans were performed on the HRRT scanner. Volume of distribution (VT) values were generated for cortical and subcortical regions and the cerebellum. Spring/summer months were defined as March to August while fall/winter months were defined as September to February and were compared through 2-tailed t-tests (SciPy library v.1.10.1 and Pinguoin library on Python v.3.8.8). Average daylight hours and temperature in New Haven, CT were obtained online (www.wunderground.com) and compared to VT with Spearman's correlations. RESULTS There were no significant differences observed between the TSPO levels of spring/summer and fall/winter months in the brain (t = 0.52, p = 0.61). Additional analysis on all individual brain regions also indicated non-significance. Likewise, no significant correlations were found between TSPO levels in the whole brain and brain regions against daylight hours (ρ= 0.05, p = 0.74), temperature (ρ = 0.04, p = 0.81), or month (ρ = 0.08, p = 0.60). Controlling TSPO gene polymorphisms and other variables had no significant effect on the outcome. CONCLUSION To the best of our knowledge, this is the first human study to investigate seasonal changes in TSPO expression. Our results can be interpreted as the lack of seasonal variability in the neuroimmune system, but important limitations include high interindividual variability, test-retest variability, specificity of the tracer, and a limited sample size. Limitations notwithstanding, our results conclude that TSPO levels in the brain are not impacted by light and temperature changes in different seasons.
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Affiliation(s)
- Waleed Ibrahim
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Jeonghyun An
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Yanghong Yang
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Kelly P. Cosgrove
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut
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Butler T, Wang X, Chiang G, Xi K, Niogi S, Glodzik L, Li Y, Razlighi QR, Zhou L, Hojjati SH, Ozsahin I, Mao X, Maloney T, Tanzi E, Rahmouni N, Tissot C, Lussier F, Shah S, Shungu D, Gupta A, De Leon M, Mozley PD, Pascoal TA, Rosa-Neto P. Reduction in Constitutively Activated Auditory Brainstem Microglia in Aging and Alzheimer's Disease. J Alzheimers Dis 2024; 99:307-319. [PMID: 38669537 DOI: 10.3233/jad-231312] [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] [Indexed: 04/28/2024]
Abstract
Background Alzheimer's disease (AD) pathology is considered to begin in the brainstem, and cerebral microglia are known to play a critical role in AD pathogenesis, yet little is known about brainstem microglia in AD. Translocator protein (TSPO) PET, sensitive to activated microglia, shows high signal in dorsal brainstem in humans, but the precise location and clinical correlates of this signal are unknown. Objective To define age and AD associations of brainstem TSPO PET signal in humans. Methods We applied new probabilistic maps of brainstem nuclei to quantify PET-measured TSPO expression over the whole brain including brainstem in 71 subjects (43 controls scanned using 11C-PK11195; 20 controls and 8 AD subjects scanned using 11C-PBR28). We focused on inferior colliculi (IC) because of visually-obvious high signal in this region, and potential relevance to auditory dysfunction in AD. We also assessed bilateral cortex. Results TSPO expression was normally high in IC and other brainstem regions. IC TSPO was decreased with aging (p = 0.001) and in AD subjects versus controls (p = 0.004). In cortex, TSPO expression was increased with aging (p = 0.030) and AD (p = 0.033). Conclusions Decreased IC TSPO expression with aging and AD-an opposite pattern than in cortex-highlights underappreciated regional heterogeneity in microglia phenotype, and implicates IC in a biological explanation for strong links between hearing loss and AD. Unlike in cerebrum, where TSPO expression is considered pathological, activated microglia in IC and other brainstem nuclei may play a beneficial, homeostatic role. Additional study of brainstem microglia in aging and AD is needed.
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Affiliation(s)
- Tracy Butler
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Xiuyuan Wang
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Gloria Chiang
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Ke Xi
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Sumit Niogi
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Lidia Glodzik
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Yi Li
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | | | - Liangdong Zhou
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | | | - Ilker Ozsahin
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Xiangling Mao
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Thomas Maloney
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Emily Tanzi
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Nesrine Rahmouni
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Montréal, QC, Canada
| | - Cécile Tissot
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Montréal, QC, Canada
| | - Firoza Lussier
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Montréal, QC, Canada
| | - Sudhin Shah
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Dikoma Shungu
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Mony De Leon
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - P David Mozley
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Tharick A Pascoal
- Departments of Neurology and Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Pedro Rosa-Neto
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Montréal, QC, Canada
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Raval NR, Wetherill RR, Wiers CE, Dubroff JG, Hillmer AT. Positron Emission Tomography of Neuroimmune Responses in Humans: Insights and Intricacies. Semin Nucl Med 2023; 53:213-229. [PMID: 36270830 PMCID: PMC11261531 DOI: 10.1053/j.semnuclmed.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 08/30/2022] [Indexed: 11/06/2022]
Abstract
The brain's immune system plays a critical role in responding to immune challenges and maintaining homeostasis. However, dysregulated neuroimmune function contributes to neurodegenerative disease and neuropsychiatric conditions. In vivo positron emission tomography (PET) imaging of the neuroimmune system has facilitated a greater understanding of its physiology and the pathology of some neuropsychiatric conditions. This review presents an in-depth look at PET findings from human neuroimmune function studies, highlighting their importance in current neuropsychiatric research. Although the majority of human PET studies feature radiotracers targeting the translocator protein 18 kDa (TSPO), this review also considers studies with other neuroimmune targets, including monoamine oxidase B, cyclooxygenase-1 and cyclooxygenase-2, nitric oxide synthase, and the purinergic P2X7 receptor. Promising new targets, such as colony-stimulating factor 1, Sphingosine-1-phosphate receptor 1, and the purinergic P2Y12 receptor, are also discussed. The significance of validating neuroimmune targets and understanding their function and expression is emphasized in this review to better identify and interpret PET results.
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Affiliation(s)
- Nakul R Raval
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT
| | - Reagan R Wetherill
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Corinde E Wiers
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jacob G Dubroff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ansel T Hillmer
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT; Department of Psychiatry, Yale University, New Haven, CT.
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6
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Butler T, Glodzik L, Wang XH, Xi K, Li Y, Pan H, Zhou L, Chiang GCY, Morim S, Wickramasuriya N, Tanzi E, Maloney T, Harvey P, Mao X, Razlighi QR, Rusinek H, Shungu DC, de Leon M, Atwood CS, Mozley PD. Positron Emission Tomography reveals age-associated hypothalamic microglial activation in women. Sci Rep 2022; 12:13351. [PMID: 35922659 PMCID: PMC9349172 DOI: 10.1038/s41598-022-17315-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
In rodents, hypothalamic inflammation plays a critical role in aging and age-related diseases. Hypothalamic inflammation has not previously been assessed in vivo in humans. We used Positron Emission Tomography (PET) with a radiotracer sensitive to the translocator protein (TSPO) expressed by activated microglia, to assess correlations between age and regional brain TSPO in a group of healthy subjects (n = 43, 19 female, aged 23-78), focusing on hypothalamus. We found robust age-correlated TSPO expression in thalamus but not hypothalamus in the combined group of women and men. This pattern differs from what has been described in rodents. Prominent age-correlated TSPO expression in thalamus in humans, but in hypothalamus in rodents, could reflect evolutionary changes in size and function of thalamus versus hypothalamus, and may be relevant to the appropriateness of using rodents to model human aging. When examining TSPO PET results in women and men separately, we found that only women showed age-correlated hypothalamic TSPO expression. We suggest this novel result is relevant to understanding a stark sex difference in human aging: that only women undergo loss of fertility-menopause-at mid-life. Our finding of age-correlated hypothalamic inflammation in women could have implications for understanding and perhaps altering reproductive aging in women.
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Affiliation(s)
- Tracy Butler
- Department of Radiology, Weill Cornell Medicine, New York, USA.
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA.
| | - Lidia Glodzik
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Xiuyuan Hugh Wang
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Ke Xi
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Yi Li
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Hong Pan
- Department of Psychiatry, Brigham and Women's Hospital, Boston, USA
| | - Liangdong Zhou
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | | | - Simon Morim
- Department of Radiology, Weill Cornell Medicine, New York, USA
| | - Nimmi Wickramasuriya
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Emily Tanzi
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Thomas Maloney
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Patrick Harvey
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Xiangling Mao
- Department of Radiology, Weill Cornell Medicine, New York, USA
| | - Qolamreza Ray Razlighi
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Henry Rusinek
- Department of Radiology, New York University, New York, USA
| | - Dikoma C Shungu
- Department of Radiology, Weill Cornell Medicine, New York, USA
| | - Mony de Leon
- Department of Radiology, Weill Cornell Medicine, New York, USA
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, 405 E 61st St, New York, NY, 10065, USA
| | - Craig S Atwood
- Department of Gerontology, University of Wisconsin, Madison, Madison, USA
| | - P David Mozley
- Department of Radiology, Weill Cornell Medicine, New York, USA
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Nutma E, Ceyzériat K, Amor S, Tsartsalis S, Millet P, Owen DR, Papadopoulos V, Tournier BB. Cellular sources of TSPO expression in healthy and diseased brain. Eur J Nucl Med Mol Imaging 2021; 49:146-163. [PMID: 33433698 PMCID: PMC8712293 DOI: 10.1007/s00259-020-05166-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/13/2020] [Indexed: 12/11/2022]
Abstract
The 18 kDa translocator protein (TSPO) is a highly conserved protein located in the outer mitochondrial membrane. TSPO binding, as measured with positron emission tomography (PET), is considered an in vivo marker of neuroinflammation. Indeed, TSPO expression is altered in neurodegenerative, neuroinflammatory, and neuropsychiatric diseases. In PET studies, the TSPO signal is often viewed as a marker of microglial cell activity. However, there is little evidence in support of a microglia-specific TSPO expression. This review describes the cellular sources and functions of TSPO in animal models of disease and human studies, in health, and in central nervous system diseases. A discussion of methods of analysis and of quantification of TSPO is also presented. Overall, it appears that the alterations of TSPO binding, their cellular underpinnings, and the functional significance of such alterations depend on many factors, notably the pathology or the animal model under study, the disease stage, and the involved brain regions. Thus, further studies are needed to fully determine how changes in TSPO binding occur at the cellular level with the ultimate goal of revealing potential therapeutic pathways.
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Affiliation(s)
- Erik Nutma
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
| | - Kelly Ceyzériat
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Division of Nuclear medicine and Molecular Imaging, University Hospitals of Geneva, Geneva, Switzerland
- Division of Radiation Oncology, Department of Oncology, University Hospitals of Geneva, Geneva, Switzerland
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Stergios Tsartsalis
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Philippe Millet
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - David R Owen
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Benjamin B Tournier
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland.
- Department of Psychiatry, University of Geneva, Geneva, Switzerland.
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Beaino W, Janssen B, Vugts DJ, de Vries HE, Windhorst AD. Towards PET imaging of the dynamic phenotypes of microglia. Clin Exp Immunol 2021; 206:282-300. [PMID: 34331705 PMCID: PMC8561701 DOI: 10.1111/cei.13649] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
There is increasing evidence showing the heterogeneity of microglia activation in neuroinflammatory and neurodegenerative diseases. It has been hypothesized that pro‐inflammatory microglia are detrimental and contribute to disease progression, while anti‐inflammatory microglia play a role in damage repair and remission. The development of therapeutics targeting the deleterious glial activity and modulating it into a regenerative phenotype relies heavily upon a clearer understanding of the microglia dynamics during disease progression and the ability to monitor therapeutic outcome in vivo. To that end, molecular imaging techniques are required to assess microglia dynamics and study their role in disease progression as well as to evaluate the outcome of therapeutic interventions. Positron emission tomography (PET) is such a molecular imaging technique, and provides unique capabilities for non‐invasive quantification of neuroinflammation and has the potential to discriminate between microglia phenotypes and define their role in the disease process. However, several obstacles limit the possibility for selective in vivo imaging of microglia phenotypes mainly related to the poor characterization of specific targets that distinguish the two ends of the microglia activation spectrum and lack of suitable tracers. PET tracers targeting translocator protein 18 kDa (TSPO) have been extensively explored, but despite the success in evaluating neuroinflammation they failed to discriminate between microglia activation statuses. In this review, we highlight the current knowledge on the microglia phenotypes in the major neuroinflammatory and neurodegenerative diseases. We also discuss the current and emerging PET imaging targets, the tracers and their potential in discriminating between the pro‐ and anti‐inflammatory microglia activation states.
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Affiliation(s)
- Wissam Beaino
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Bieneke Janssen
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Danielle J Vugts
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Helga E de Vries
- Department of Molecular Cell Biology and Immunology, MS Center Amsterdam, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
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Chaney AM, Lopez-Picon FR, Serrière S, Wang R, Bochicchio D, Webb SD, Vandesquille M, Harte MK, Georgiadou C, Lawrence C, Busson J, Vercouillie J, Tauber C, Buron F, Routier S, Reekie T, Snellman A, Kassiou M, Rokka J, Davies KE, Rinne JO, Salih DA, Edwards FA, Orton LD, Williams SR, Chalon S, Boutin H. Prodromal neuroinflammatory, cholinergic and metabolite dysfunction detected by PET and MRS in the TgF344-AD transgenic rat model of AD: a collaborative multi-modal study. Am J Cancer Res 2021; 11:6644-6667. [PMID: 34093845 PMCID: PMC8171096 DOI: 10.7150/thno.56059] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/15/2021] [Indexed: 12/25/2022] Open
Abstract
Mouse models of Alzheimer's disease (AD) are valuable but do not fully recapitulate human AD pathology, such as spontaneous Tau fibril accumulation and neuronal loss, necessitating the development of new AD models. The transgenic (TG) TgF344-AD rat has been reported to develop age-dependent AD features including neuronal loss and neurofibrillary tangles, despite only expressing APP and PSEN1 mutations, suggesting an improved modelling of AD hallmarks. Alterations in neuronal networks as well as learning performance and cognition tasks have been reported in this model, but none have combined a longitudinal, multimodal approach across multiple centres, which mimics the approaches commonly taken in clinical studies. We therefore aimed to further characterise the progression of AD-like pathology and cognition in the TgF344-AD rat from young-adults (6 months (m)) to mid- (12 m) and advanced-stage (18 m, 25 m) of the disease. Methods: TgF344-AD rats and wild-type (WT) littermates were imaged at 6 m, 12 m and 18 m with [18F]DPA-714 (TSPO, neuroinflammation), [18F]Florbetaben (Aβ) and [18F]ASEM (α7-nicotinic acetylcholine receptor) and with magnetic resonance spectroscopy (MRS) and with (S)-[18F]THK5117 (Tau) at 15 and 25 m. Behaviour tests were also performed at 6 m, 12 m and 18 m. Immunohistochemistry (CD11b, GFAP, Aβ, NeuN, NeuroChrom) and Tau (S)-[18F]THK5117 autoradiography, immunohistochemistry and Western blot were also performed. Results: [18F]DPA-714 positron emission tomography (PET) showed an increase in neuroinflammation in TG vs wildtype animals from 12 m in the hippocampus (+11%), and at the advanced-stage AD in the hippocampus (+12%), the thalamus (+11%) and frontal cortex (+14%). This finding coincided with strong increases in brain microgliosis (CD11b) and astrogliosis (GFAP) at these time-points as assessed by immunohistochemistry. In vivo [18F]ASEM PET revealed an age-dependent increase uptake in the striatum and pallidum/nucleus basalis of Meynert in WT only, similar to that observed with this tracer in humans, resulting in TG being significantly lower than WT by 18 m. In vivo [18F]Florbetaben PET scanning detected Aβ accumulation at 18 m, and (S)-[18F]THK5117 PET revealed subsequent Tau accumulation at 25m in hippocampal and cortical regions. Aβ plaques were low but detectable by immunohistochemistry from 6 m, increasing further at 12 and 18 m with Tau-positive neurons adjacent to Aβ plaques at 18 m. NeuroChrom (a pan neuronal marker) immunohistochemistry revealed a loss of neuronal staining at the Aβ plaques locations, while NeuN labelling revealed an age-dependent decrease in hippocampal neuron number in both genotypes. Behavioural assessment using the novel object recognition task revealed that both WT & TgF344-AD animals discriminated the novel from familiar object at 3 m and 6 m of age. However, low levels of exploration observed in both genotypes at later time-points resulted in neither genotype successfully completing the task. Deficits in social interaction were only observed at 3 m in the TgF344-AD animals. By in vivo MRS, we showed a decrease in neuronal marker N-acetyl-aspartate in the hippocampus at 18 m (-18% vs age-matched WT, and -31% vs 6 m TG) and increased Taurine in the cortex of TG (+35% vs age-matched WT, and +55% vs 6 m TG). Conclusions: This multi-centre multi-modal study demonstrates, for the first time, alterations in brain metabolites, cholinergic receptors and neuroinflammation in vivo in this model, validated by robust ex vivo approaches. Our data confirm that, unlike mouse models, the TgF344-AD express Tau pathology that can be detected via PET, albeit later than by ex vivo techniques, and is a useful model to assess and longitudinally monitor early neurotransmission dysfunction and neuroinflammation in AD.
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Albrecht DS, Kim M, Akeju O, Torrado-Carvajal A, Edwards RR, Zhang Y, Bergan C, Protsenko E, Kucyi A, Wasan AD, Hooker JM, Napadow V, Loggia ML. The neuroinflammatory component of negative affect in patients with chronic pain. Mol Psychiatry 2021; 26:864-874. [PMID: 31138890 PMCID: PMC7001732 DOI: 10.1038/s41380-019-0433-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 03/05/2019] [Accepted: 04/11/2019] [Indexed: 01/29/2023]
Abstract
Negative affect (NA) is a significant cause of disability for chronic pain patients. While little is known about the mechanism underlying pain-comorbid NA, previous studies have implicated neuroinflammation in the pathophysiology of both depression and chronic pain. Here, we tested the hypothesis that NA in pain patients is linked to elevations in the brain levels of the glial marker 18 kDa translocator protein (TSPO), and changes in functional connectivity. 25 cLBP patients (42.4 ± 13 years old; 13F, 12M) with chronic low back pain (cLBP) and 27 healthy control subjects (48.9 ± 13 years old; 14F, 13M) received an integrated (i.e., simultaneous) positron emission tomography (PET)/magnetic resonance imaging (MRI) brain scan with the second-generation TSPO ligand [11C]PBR28. The relationship between [11C]PBR28 signal and NA was assessed first with regression analyses against Beck Depression Inventory (BDI) scores in patients, and then by comparing cLBP patients with little-to-no, or mild-to-moderate depression against healthy controls. Further, the relationship between PET signal, BDI and frontolimbic functional connectivity was evaluated in patients with mediation models. PET signal was positively associated with BDI scores in patients, and significantly elevated in patients with mild-to-moderate (but not low) depression compared with controls, in anterior middle and pregenual anterior cingulate cortices (aMCC, pgACC). In the pgACC, PET signal was also associated with this region's functional connectivity to the dorsolateral PFC (pgACC-dlPFC), and mediated of the association between pgACC-dlPFC connectivity and BDI. These observations support a role for glial activation in pain-comorbid NA, identifying in neuroinflammation a potential therapeutic target for this condition.
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Affiliation(s)
- DS Albrecht
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA
| | - M Kim
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA
| | - O Akeju
- Department of Anesthesia, Critical Care and Pain Medicine, MGH / HMS, Boston, MA
| | - A Torrado-Carvajal
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA
| | - RR Edwards
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, HMS, Boston, MA
| | - Y Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, MGH / HMS, Boston, MA
| | - C Bergan
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA
| | - E Protsenko
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA
| | - A Kucyi
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA,Department of Neurology, Stanford University Medical Center, Stanford, CA
| | - AD Wasan
- Departments of Anesthesiology and Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - JM Hooker
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA
| | - V Napadow
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA,Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, HMS, Boston, MA
| | - ML Loggia
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School (MGH/HMS), Boston, MA,Corresponding author, lead contact: Marco L. Loggia, PhD, A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth Street, Room 2301, Charlestown, MA 02129,
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11
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Wright P, Veronese M, Mazibuko N, Turkheimer FE, Rabiner EA, Ballard CG, Williams SCR, Hari Narayanan AK, Osrah B, Williams R, Marques TR, Howes OD, Roncaroli F, O'Sullivan MJ. Patterns of Mitochondrial TSPO Binding in Cerebral Small Vessel Disease: An in vivo PET Study With Neuropathological Comparison. Front Neurol 2020; 11:541377. [PMID: 33178101 PMCID: PMC7596201 DOI: 10.3389/fneur.2020.541377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/20/2020] [Indexed: 12/11/2022] Open
Abstract
Small vessel disease (SVD) is associated with cognitive impairment in older age and be implicated in vascular dementia. Post-mortem studies show proliferation of activated microglia in the affected white matter. However, the role of inflammation in SVD pathogenesis is incompletely understood and better biomarkers are needed. We hypothesized that expression of the 18 kDa translocator protein (TSPO), a marker of microglial activation, would be higher in SVD. Positron emission tomography (PET) was performed with the second-generation TSPO ligand [11C]PBR28 in 11 participants with SVD. TSPO binding was evaluated by a two-tissue compartment model, with and without a vascular binding component, in white matter hyperintensities (WMH) and normal-appearing white matter (NAWM). In post-mortem tissue, in a separate cohort of individuals with SVD, immunohistochemistry was performed for TSPO and a pan-microglial marker Iba1. Kinetic modeling showed reduced tracer volume and blood volume fraction in WMH compared with NAWM, but a significant increase in vascular binding. Vascular [11C]PBR28 binding was also increased compared with normal-appearing white matter of healthy participants free of SVD. Immunohistochemistry showed a diffuse increase in microglial staining (with Iba1) in sampled tissue in SVD compared with control samples, but with only a subset of microglia staining positively for TSPO. Intense TSPO staining was observed in the vicinity of damaged small blood vessels, which included perivascular macrophages. The results suggest an altered phenotype of activated microglia, with reduced TSPO expression, in the areas of greatest white matter ischemia in SVD, with implications for the interpretation of TSPO PET studies in older individuals or those with vascular risk factors.
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Affiliation(s)
- Paul Wright
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Ndabezinhle Mazibuko
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Federico E. Turkheimer
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Eugenii A. Rabiner
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
- Invicro, London, United Kingdom
| | - Clive G. Ballard
- College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Steven C. R. Williams
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Avinash Kumar Hari Narayanan
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Clinical Neuroscience, Salford Royal Foundation Trust, Salford, United Kingdom
| | - Bahiya Osrah
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Clinical Neuroscience, Salford Royal Foundation Trust, Salford, United Kingdom
| | - Ricky Williams
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Clinical Neuroscience, Salford Royal Foundation Trust, Salford, United Kingdom
| | - Tiago R. Marques
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Oliver D. Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Federico Roncaroli
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Clinical Neuroscience, Salford Royal Foundation Trust, Salford, United Kingdom
| | - Michael J. O'Sullivan
- Department of Neuroimaging, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, United Kingdom
- University of Queensland Centre for Clinical Research, Brisbane, QLD, Australia
- Department of Neurology, The Royal Brisbane and Women's Hospital, Herston, QLD, Australia
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12
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Effects of age, BMI and sex on the glial cell marker TSPO - a multicentre [ 11C]PBR28 HRRT PET study. Eur J Nucl Med Mol Imaging 2019; 46:2329-2338. [PMID: 31363804 PMCID: PMC6717599 DOI: 10.1007/s00259-019-04403-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/14/2019] [Indexed: 01/25/2023]
Abstract
Purpose The purpose of this study was to investigate the effects of ageing, sex and body mass index (BMI) on translocator protein (TSPO) availability in healthy subjects using positron emission tomography (PET) and the radioligand [11C]PBR28. Methods [11C]PBR28 data from 140 healthy volunteers (72 males and 68 females; N = 78 with HAB and N = 62 MAB genotype; age range 19–80 years; BMI range 17.6–36.9) were acquired with High Resolution Research Tomograph at three centres: Karolinska Institutet (N = 53), Turku PET centre (N = 62) and Yale University PET Center (N = 25). The total volume of distribution (VT) was estimated in global grey matter, frontal, temporal, occipital and parietal cortices, hippocampus and thalamus using multilinear analysis 1. The effects of age, BMI and sex on TSPO availability were investigated using linear mixed effects model, with TSPO genotype and PET centre specified as random intercepts. Results There were significant positive correlations between age and VT in the frontal and temporal cortex. BMI showed a significant negative correlation with VT in all regions. Additionally, significant differences between males and females were observed in all regions, with females showing higher VT. A subgroup analysis revealed a positive correlation between VT and age in all regions in male subjects, whereas age showed no effect on TSPO levels in female subjects. Conclusion These findings provide evidence that individual biological properties may contribute significantly to the high variation shown in TSPO binding estimates, and suggest that age, BMI and sex can be confounding factors in clinical studies. Electronic supplementary material The online version of this article (10.1007/s00259-019-04403-7) contains supplementary material, which is available to authorized users.
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13
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Kim MJ, McGwier M, Jenko KJ, Snow J, Morse C, Zoghbi SS, Pike VW, Innis RB, Kreisl WC. Neuroinflammation in frontotemporal lobar degeneration revealed by 11 C-PBR28 PET. Ann Clin Transl Neurol 2019; 6:1327-1331. [PMID: 31353865 PMCID: PMC6649481 DOI: 10.1002/acn3.50802] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/15/2019] [Accepted: 05/15/2019] [Indexed: 12/31/2022] Open
Abstract
This study used 11 C-PBR28 positron emission tomography (PET) imaging to determine whether levels of 18-kDa translocator protein (TSPO), an inflammation-specific biomarker, are increased in frontotemporal lobar degeneration (FTLD) patients. 11 C-PBR28, 18 F-FDG, and 11 C-PIB brain PET scans, as well as magnetic resonance imaging (MRI), were conducted in four FTLD patients and 22 healthy controls. 11 C-PBR28 scans revealed that all FTLD patients showed increased TSPO binding versus controls. Significantly greater increases in TSPO were observed in the frontal, lateral temporal, parietal, and occipital cortices, topographically consistent with individual clinical phenotypes and with brain MRI and 18 F-FDG PET. Amyloid burden was not increased.
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Affiliation(s)
- Min-Jeong Kim
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - Meghan McGwier
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - Kimberly J. Jenko
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - Joseph Snow
- Office of the Clinical DirectorNational Institute of Mental HealthBethesdaMaryland
| | - Cheryl Morse
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - Sami S. Zoghbi
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - Victor W. Pike
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - Robert B. Innis
- Molecular Imaging BranchNational Institute of Mental HealthBethesdaMaryland
| | - William C. Kreisl
- Taub Institute for Research on Alzheimer's Disease and the Aging BrainColumbia UniversityNew YorkNew York
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14
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Head-to-head comparison of 11C-PBR28 and 11C-ER176 for quantification of the translocator protein in the human brain. Eur J Nucl Med Mol Imaging 2019; 46:1822-1829. [DOI: 10.1007/s00259-019-04349-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
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15
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Dickstein LP, Liow JS, Austermuehle A, Zoghbi S, Inati SK, Zaghloul K, Zanotti-Fregonara P, Theodore WH. Neuroinflammation in neocortical epilepsy measured by PET imaging of translocator protein. Epilepsia 2019; 60:1248-1254. [PMID: 31144767 DOI: 10.1111/epi.15967] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 04/25/2019] [Accepted: 04/25/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Neuroinflammation, implicated in epilepsy, can be imaged in humans with positron emission tomography (PET) ligands for translocator protein 18 kDa (TSPO). Previous studies in patients with temporal lobe epilepsy and mesial temporal sclerosis found increased [11C]PBR28 uptake ipsilateral to seizure foci. Neocortical foci present more difficult localization problems and more variable underlying pathology. METHODS We studied 11 patients with neocortical seizure foci using [11C]PBR28 or [11C] N,N-diethyl-2-(4-methoxyphenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidine-3-acetamide (DPA) 713, and 31 healthy volunteers. Seizure foci were identified with structural magnetic resonance imaging (MRI) and ictal video-electroencephalography (EEG) monitoring. Six patients had surgical resections; five had focal cortical dysplasia type 2A or B and one microdysgenesis. Brain regions were delineated using FreeSurfer and T1-weighted MRI. We measured brain radioligand uptake (standardized uptake values [SUVs]) in ipsilateral and contralateral regions, to compare calculated asymmetry indices [AIs; 200% *(ipsilateral - contralateral)/(ipsilateral + contralateral)] between epilepsy patients and controls, as well as absolute [11C]PBR28 binding as the ratio of distribution volume to free fraction (VT /fP ) in 9 patients (5 high affinity and 4 medium affinity binders) and 11 age-matched volunteers (5 high-affinity and 6 medium affinity) who had metabolite-corrected arterial input functions measured. RESULTS Nine of 11 patients had AIs exceeding control mean 95% confidence intervals in at least one region consistent with the seizure focus. Three of the nine had normal MRI. There was a nonsignificant trend for patients to have higher binding than volunteers both ipsilateral and contralateral to the focus in the group that had absolute binding measured. SIGNIFICANCE Our study demonstrates the presence of focal and distributed inflammation in neocortical epilepsy. There may be a role for TSPO PET for evaluation of patients with suspected neocortical seizure foci, particularly when other imaging modalities are unrevealing. However, a complex method, inherent variability, and increased binding in regions outside seizure foci will limit applicability.
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Affiliation(s)
- Leah P Dickstein
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Alison Austermuehle
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Sami Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Sara K Inati
- EEG Section, OCD, National Institute of Neurological Disorders and Stroke, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Kareem Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - William H Theodore
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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16
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Richards EM, Zanotti-Fregonara P, Fujita M, Newman L, Farmer C, Ballard ED, Machado-Vieira R, Yuan P, Niciu MJ, Lyoo CH, Henter ID, Salvadore G, Drevets WC, Kolb H, Innis RB, Zarate Jr CA. PET radioligand binding to translocator protein (TSPO) is increased in unmedicated depressed subjects. EJNMMI Res 2018; 8:57. [PMID: 29971587 PMCID: PMC6029989 DOI: 10.1186/s13550-018-0401-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/30/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Inflammation is associated with major depressive disorder (MDD). Translocator protein 18 kDa (TSPO), a putative biomarker of neuroinflammation, is quantified using positron emission tomography (PET) and 11C-PBR28, a TSPO tracer. We sought to (1) investigate TSPO binding in MDD subjects currently experiencing a major depressive episode, (2) investigate the effects of antidepressants on TSPO binding, and (3) determine the relationship of peripheral and central inflammatory markers to cerebral TSPO binding. Twenty-eight depressed MDD subjects (unmedicated (n = 12) or medicated (n = 16)) and 20 healthy controls (HC) underwent PET imaging using 11C-PBR28. Total distribution volume (VT, proportional to Bmax/Kd) was measured and corrected with the free fraction in plasma (fp). The subgenual prefrontal cortex (sgPFC) and anterior cingulate cortex (ACC) were the primary regions of interest. Peripheral blood samples and cerebrospinal fluid were analyzed to investigate the relationship between TSPO binding and peripheral and central inflammatory markers, including interleukins and neurotrophic factors previously linked to depression. RESULTS TSPO binding was higher in MDD versus HC in the sgPFC (Cohen's d = 0.64, p = .038, 95% CI 0.04-1.24) and ACC (d = 0.60, p = .049, 95% CI 0.001-1.21), though these comparisons missed the corrected threshold for statistical significance (α = .025). Exploratory analyses demonstrated that unmedicated MDD subjects had the highest level of TSPO binding, followed by medicated MDD subjects, who did not differ from HC. TSPO binding correlated with interleukin-5 in cerebrospinal fluid but with no other central inflammatory markers. CONCLUSIONS This study found a trend towards increased TSPO binding in the brains of MDD subjects, and post hoc analysis extended these findings by demonstrating that this abnormality is significant in unmedicated (but not medicated) MDD subjects.
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Affiliation(s)
- Erica M. Richards
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | | | - Masahiro Fujita
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Laura Newman
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Cristan Farmer
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Elizabeth D. Ballard
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Rodrigo Machado-Vieira
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, TX USA
| | - Peixiong Yuan
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Mark J. Niciu
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Chul Hyoung Lyoo
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Ioline D. Henter
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | | | | | - Hartmuth Kolb
- Janssen Research and Development, LLC, Titusville, NJ USA
| | - Robert B. Innis
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
| | - Carlos A. Zarate Jr
- Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Building 10, CRC Room 6-5340, 10 Center Drive, Bethesda, MD 20892 USA
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