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Bäckström T, Doverskog M, Blackburn TP, Scharschmidt BF, Felipo V. Allopregnanolone and its antagonist modulate neuroinflammation and neurological impairment. Neurosci Biobehav Rev 2024; 161:105668. [PMID: 38608826 DOI: 10.1016/j.neubiorev.2024.105668] [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: 10/19/2023] [Revised: 03/18/2024] [Accepted: 04/07/2024] [Indexed: 04/14/2024]
Abstract
Neuroinflammation accompanies several brain disorders, either as a secondary consequence or as a primary cause and may contribute importantly to disease pathogenesis. Neurosteroids which act as Positive Steroid Allosteric GABA-A receptor Modulators (Steroid-PAM) appear to modulate neuroinflammation and their levels in the brain may vary because of increased or decreased local production or import from the systemic circulation. The increased synthesis of steroid-PAMs is possibly due to increased expression of the mitochondrial cholesterol transporting protein (TSPO) in neuroinflammatory tissue, and reduced production may be due to changes in the enzymatic activity. Microglia and astrocytes play an important role in neuroinflammation, and their production of inflammatory mediators can be both activated and inhibited by steroid-PAMs and GABA. What is surprising is the finding that both allopregnanolone, a steroid-PAM, and golexanolone, a novel GABA-A receptor modulating steroid antagonist (GAMSA), can inhibit microglia and astrocyte activation and normalize their function. This review focuses on the role of steroid-PAMs in neuroinflammation and their importance in new therapeutic approaches to CNS and liver disease.
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Affiliation(s)
| | | | | | | | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
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2
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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; 30:165-175. [PMID: 38575831 PMCID: PMC11371857 DOI: 10.1007/s13365-024-01200-3] [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: 12/01/2023] [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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3
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Ottoy J, De Picker L, Kang MS. Microglial Positron Emission Tomography Imaging In Vivo : Positron Emission Tomography Radioligands: Utility in Research and Clinical Practice. ADVANCES IN NEUROBIOLOGY 2024; 37:579-589. [PMID: 39207714 DOI: 10.1007/978-3-031-55529-9_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Microglia, the resident immune cells of the central nervous system (CNS) play a key role in regulating and maintaining homeostasis in the brain. However, the CNS is also vulnerable to infections and inflammatory processes. In response to CNS perturbations, microglia become reactive, notably with expression of the translocator protein (TSPO), primarily on their outer mitochondrial membrane. Despite TSPO being commonly used as a marker for microglia, it is also present in other cell types such as astrocytes. Positron emission tomography (PET) ligands that target the TSPO enable the noninvasive detection and quantification of glial reactivity. While some limitations were raised, TSPO PET remains an attractive biomarker of CNS infection and inflammation. This book chapter delves into the development and application of microglial PET imaging with a focus on the TSPO PET. First, we provide an overview of the evolution of TSPO PET radioligands from first-generation to second-generation ligands and their applications in studying neuroinflammation (or CNS inflammation). Subsequently, we discuss the limitations and challenges associated with TSPO PET. Then we go on to explore non-TSPO targets for microglial PET imaging. Finally, we conclude with future directions for research and clinical practice in this field.
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Affiliation(s)
- Julie Ottoy
- Dr. Sandra E. Black Centre for Brain Resilience and Recovery, LC Campbell Cognitive Neurology, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Livia De Picker
- Collaborative Antwerp Psychiatric Research Institute, University of Antwerp, Antwerp, Belgium
- University Psychiatric Hospital Campus Duffel, Duffel, Belgium
| | - Min Su Kang
- Dr. Sandra E. Black Centre for Brain Resilience and Recovery, LC Campbell Cognitive Neurology, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
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Shah S, Turner ML, Chen X, Ances BM, Hammoud DA, Tucker EW. The Promise of Molecular Imaging: Focus on Central Nervous System Infections. J Infect Dis 2023; 228:S311-S321. [PMID: 37788502 PMCID: PMC11009511 DOI: 10.1093/infdis/jiad223] [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] [Indexed: 10/05/2023] Open
Abstract
Central nervous system (CNS) infections can lead to high mortality and severe morbidity. Diagnosis, monitoring, and assessing response to therapy of CNS infections is particularly challenging with traditional tools, such as microbiology, due to the dangers associated with invasive CNS procedures (ie, biopsy or surgical resection) to obtain tissues. Molecular imaging techniques like positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging have long been used to complement anatomic imaging such as computed tomography (CT) and magnetic resonance imaging (MRI), for in vivo evaluation of disease pathophysiology, progression, and treatment response. In this review, we detail the use of molecular imaging to delineate host-pathogen interactions, elucidate antimicrobial pharmacokinetics, and monitor treatment response. We also discuss the utility of pathogen-specific radiotracers to accurately diagnose CNS infections and strategies to develop radiotracers that would cross the blood-brain barrier.
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Affiliation(s)
- Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Mitchell L Turner
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Xueyi Chen
- Department of Pediatrics, Center for Infection and Inflammation Imaging Research, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Beau M Ances
- Department of Neurology, Washington University, St Louis, Missouri, USA
| | - Dima A Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Elizabeth W Tucker
- Department of Anesthesiology and Critical Care Medicine, Center for Infection and Inflammation Imaging Research, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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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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Martinez-Orengo N, Tahmazian S, Lai J, Wang Z, Sinharay S, Schreiber-Stainthorp W, Basuli F, Maric D, Reid W, Shah S, Hammoud DA. Assessing organ-level immunoreactivity in a rat model of sepsis using TSPO PET imaging. Front Immunol 2022; 13:1010263. [PMID: 36439175 PMCID: PMC9685400 DOI: 10.3389/fimmu.2022.1010263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
There is current need for new approaches to assess/measure organ-level immunoreactivity and ensuing dysfunction in systemic inflammatory response syndrome (SIRS) and sepsis, in order to protect or recover organ function. Using a rat model of systemic sterile inflammatory shock (intravenous LPS administration), we performed PET imaging with a translocator protein (TSPO) tracer, [18F]DPA-714, as a biomarker for reactive immunoreactive changes in the brain and peripheral organs. In vivo dynamic PET/CT scans showed increased [18F]DPA-714 binding in the brain, lungs, liver and bone marrow, 4 hours after LPS injection. Post-LPS mean standard uptake values (SUVmean) at equilibrium were significantly higher in those organs compared to baseline. Changes in spleen [18F]DPA-714 binding were variable but generally decreased after LPS. SUVmean values in all organs, except the spleen, positively correlated with several serum cytokines/chemokines. In vitro measures of TSPO expression and immunofluorescent staining validated the imaging results. Noninvasive molecular imaging with [18F]DPA-714 PET in a rat model of systemic sterile inflammatory shock, along with in vitro measures of TSPO expression, showed brain, liver and lung inflammation, spleen monocytic efflux/lymphocytic activation and suggested increased bone marrow hematopoiesis. TSPO PET imaging can potentially be used to quantify SIRS and sepsis-associated organ-level immunoreactivity and assess the effectiveness of therapeutic and preventative approaches for associated organ failures, in vivo.
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Affiliation(s)
- Neysha Martinez-Orengo
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Sarine Tahmazian
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Jianhao Lai
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Zeping Wang
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - William Schreiber-Stainthorp
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Falguni Basuli
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, United States
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - William Reid
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Dima A. Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Dima A. Hammoud,
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7
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Yim A, Smith C, Brown AM. Osteopontin/secreted phosphoprotein-1 harnesses glial-, immune-, and neuronal cell ligand-receptor interactions to sense and regulate acute and chronic neuroinflammation. Immunol Rev 2022; 311:224-233. [PMID: 35451082 PMCID: PMC9790650 DOI: 10.1111/imr.13081] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 12/31/2022]
Abstract
Osteopontin (OPN) also known by its official gene designation secreted phosphoprotein-1 (SPP1) is a fascinating, multifunctional protein expressed in a number of cell types that functions not only in intercellular communication, but also in the extracellular matrix (ECM). OPN/SPP1 possesses cytokine, chemokine, and signal transduction functions by virtue of modular structural motifs that provide interaction surfaces for integrins and CD44-variant receptors. In humans, there are three experimentally verified splice variants of OPN/SPP1 and CD44's ten exons are also alternatively spiced in a cell/tissue-specific manner, although very little is known about how this is regulated in the central nervous system (CNS). Post-translational modifications of phosphorylation, glycosylation, and localized cleavage by specific proteases in the cells and tissues where OPN/SPP1 functions, provides additional layers of specificity. However, the former make elucidating the exact molecular mechanisms of OPN/SPP1 function more complex. Flexibility in OPN/SPP1 structure and its engagement with integrins having the ability to transmit signals in inside-out and outside-in direction, is likely why OPN/SPP1 can serve as an early detector of inflammation and ongoing tissue damage in response to cancer, stroke, traumatic brain injury, pathogenic infection, and neurodegeneration, processes that impair tissue homeostasis. This review will focus on what is currently known about OPN/SPP1 function in the brain.
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Affiliation(s)
- Ashley Yim
- NeurologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Christian Smith
- NeurologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Amanda M. Brown
- NeurologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
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8
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van der Geest KSM, Sandovici M, Nienhuis PH, Slart RHJA, Heeringa P, Brouwer E, Jiemy WF. Novel PET Imaging of Inflammatory Targets and Cells for the Diagnosis and Monitoring of Giant Cell Arteritis and Polymyalgia Rheumatica. Front Med (Lausanne) 2022; 9:902155. [PMID: 35733858 PMCID: PMC9207253 DOI: 10.3389/fmed.2022.902155] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/13/2022] [Indexed: 12/26/2022] Open
Abstract
Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are two interrelated inflammatory diseases affecting patients above 50 years of age. Patients with GCA suffer from granulomatous inflammation of medium- to large-sized arteries. This inflammation can lead to severe ischemic complications (e.g., irreversible vision loss and stroke) and aneurysm-related complications (such as aortic dissection). On the other hand, patients suffering from PMR present with proximal stiffness and pain due to inflammation of the shoulder and pelvic girdles. PMR is observed in 40-60% of patients with GCA, while up to 21% of patients suffering from PMR are also affected by GCA. Due to the risk of ischemic complications, GCA has to be promptly treated upon clinical suspicion. The treatment of both GCA and PMR still heavily relies on glucocorticoids (GCs), although novel targeted therapies are emerging. Imaging has a central position in the diagnosis of GCA and PMR. While [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) has proven to be a valuable tool for diagnosis of GCA and PMR, it possesses major drawbacks such as unspecific uptake in cells with high glucose metabolism, high background activity in several non-target organs and a decrease of diagnostic accuracy already after a short course of GC treatment. In recent years, our understanding of the immunopathogenesis of GCA and, to some extent, PMR has advanced. In this review, we summarize the current knowledge on the cellular heterogeneity in the immunopathology of GCA/PMR and discuss how recent advances in specific tissue infiltrating leukocyte and stromal cell profiles may be exploited as a source of novel targets for imaging. Finally, we discuss prospective novel PET radiotracers that may be useful for the diagnosis and treatment monitoring in GCA and PMR.
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Affiliation(s)
- Kornelis S. M. van der Geest
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Maria Sandovici
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Pieter H. Nienhuis
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Riemer H. J. A. Slart
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Department of Biomedical Photonic Imaging Group, University of Twente, Enschede, Netherlands
| | - Peter Heeringa
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Elisabeth Brouwer
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - William F. Jiemy
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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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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O'Brien CA, Bennett FC, Bennett ML. Microglia in antiviral immunity of the brain and spinal cord. Semin Immunol 2022; 60:101650. [PMID: 36099864 PMCID: PMC9934594 DOI: 10.1016/j.smim.2022.101650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/17/2022] [Accepted: 08/30/2022] [Indexed: 01/15/2023]
Abstract
Viral infections of the central nervous system (CNS) are a significant cause of neurological impairment and mortality worldwide. As tissue resident macrophages, microglia are critical initial responders to CNS viral infection. Microglia seem to coordinate brain-wide antiviral responses of both brain resident cells and infiltrating immune cells. This review discusses how microglia may promote this antiviral response at a molecular level, from potential mechanisms of virus recognition to downstream cytokine responses and interaction with antiviral T cells. Recent advancements in genetic tools to specifically target microglia in vivo promise to further our understanding about the precise mechanistic role of microglia in CNS infection.
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Affiliation(s)
- Carleigh A O'Brien
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States.
| | - F Chris Bennett
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States; Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Mariko L Bennett
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
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11
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PET imaging in HIV patients. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00037-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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12
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Chauveau F, Becker G, Boutin H. Have (R)-[ 11C]PK11195 challengers fulfilled the promise? A scoping review of clinical TSPO PET studies. Eur J Nucl Med Mol Imaging 2021; 49:201-220. [PMID: 34387719 PMCID: PMC8712292 DOI: 10.1007/s00259-021-05425-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE The prototypical TSPO radiotracer (R)-[11C]PK11195 has been used in humans for more than thirty years to visualize neuroinflammation in several pathologies. Alternative radiotracers have been developed to improve signal-to-noise ratio and started to be tested clinically in 2008. Here we examined the scientific value of these "(R)-[11C]PK11195 challengers" in clinical research to determine if they could supersede (R)-[11C]PK11195. METHODS A systematic MEDLINE (PubMed) search was performed (up to end of year 2020) to extract publications reporting TSPO PET in patients with identified pathologies, excluding studies in healthy subjects and methodological studies. RESULTS Of the 288 publications selected, 152 used 13 challengers, and 142 used (R)-[11C]PK11195. Over the last 20 years, the number of (R)-[11C]PK11195 studies remained stable (6 ± 3 per year), but was surpassed by the total number of challenger studies for the last 6 years. In total, 3914 patients underwent a TSPO PET scan, and 47% (1851 patients) received (R)-[11C]PK11195. The 2 main challengers were [11C]PBR28 (24%-938 patients) and [18F]FEPPA (11%-429 patients). Only one-in-ten patients (11%-447) underwent 2 TSPO scans, among whom 40 (1%) were scanned with 2 different TSPO radiotracers. CONCLUSIONS Generally, challengers confirmed disease-specific initial (R)-[11C]PK11195 findings. However, while their better signal-to-noise ratio seems particularly useful in diseases with moderate and widespread neuroinflammation, most challengers present an allelic-dependent (Ala147Thr polymorphism) TSPO binding and genetic stratification is hindering their clinical implementation. As new challengers, insensitive to TSPO human polymorphism, are about to enter clinical evaluation, we propose this systematic review to be regularly updated (living review).
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Affiliation(s)
- Fabien Chauveau
- University of Lyon, Lyon Neuroscience Research Center (CRNL), CNRS UMR5292, INSERM U1028, University Lyon 1, Lyon, France.
| | - Guillaume Becker
- GIGA - CRC In Vivo Imaging, University Liege, Liege, Belgium
- University of Lyon, CarMeN Laboratory, INSERM U1060, University Lyon 1, Hospices Civils Lyon, Lyon, France
| | - Hervé Boutin
- Faculty of Biology Medicine and Health, Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK.
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK.
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK.
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Alagaratnam J, Winston A. Molecular neuroimaging of inflammation in HIV. Clin Exp Immunol 2021; 210:14-23. [PMID: 35020855 PMCID: PMC9585552 DOI: 10.1093/cei/uxab013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/13/2021] [Accepted: 11/03/2021] [Indexed: 01/12/2023] Open
Abstract
People with HIV now have near-normal life expectancies due to the success of effective combination antiretroviral therapy (cART). Following cART initiation, immune recovery occurs, and opportunistic diseases become rare. Despite this, high rates of non-infectious comorbidities persist in treated people with HIV, hypothesized to be related to persistent immuno-activation. One such comorbidity is cognitive impairment, which may partly be driven by ongoing neuro-inflammation in otherwise effectively treated people with HIV. In order to develop therapeutic interventions to address neuro-inflammation in effectively treated people with HIV, a deeper understanding of the pathogenic mechanisms driving persistent neuro-inflammatory responses and the ability to better characterize and measure neuro-inflammation in the central nervous system is required. This review highlights recent advances in molecular neuroimaging techniques which have the potential to assess neuro-inflammatory responses within the central nervous system in HIV disease. Proton magnetic resonance spectroscopy (1H-MRS) has been utilized to assess neuro-inflammatory responses since early in the HIV pandemic and shows promise in recent studies assessing different antiretroviral regimens. 1H-MRS is widely available in both resource-rich and some resource-constrained settings and is relatively inexpensive. Brain positron emission tomography (PET) imaging using Translocator Protein (TSPO) radioligands is a rapidly evolving field; newer TSPO-radioligands have lower signal-to-noise ratio and have the potential to localize neuro-inflammation within the brain in people with HIV. As HIV therapeutics evolve, people with HIV continue to age and develop age-related comorbidities including cognitive disorders. The use of novel neuroimaging modalities in the field is likely to advance in order to rapidly assess novel therapeutic interventions and may play a role in future clinical assessments.
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Affiliation(s)
- Jasmini Alagaratnam
- Correspondence: Jasmini Alagaratnam, Clinical Trials Centre, Winston Churchill Wing, St. Mary’s Hospital, Praed Street, London W2 1NY, 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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14
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A longitudinal analysis of brain extracellular free water in HIV infected individuals. Sci Rep 2021; 11:8273. [PMID: 33859326 PMCID: PMC8050285 DOI: 10.1038/s41598-021-87801-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/05/2021] [Indexed: 11/13/2022] Open
Abstract
Initiation of combination antiretroviral therapy (cART) reduces inflammation in HIV-infected (HIV+) individuals. Recent studies demonstrated that diffusion MRI based extracellular free water (FW) modeling can be sensitive to neuroinflammation. Here, we investigate the FW in HIV-infection, its temporal evolution, and its association with blood markers, and cognitive scores. Using 96 age-matched participants, we found that FW was significantly elevated in grey and white matter in cART-naïve HIV+ compared to HIV-uninfected (HIV−) individuals at baseline. These increased FW values positively correlated with neurofilament light chain (NfL) and negatively correlated with CD4 counts. FW in grey and white matter, as well as NfL decreased in the HIV+ after 12 weeks of cART treatment. No significant FW differences were noted between the HIV+ and HIV− cohorts at 1 and 2-year follow-up. Results suggest that FW elevation in cART-naïve HIV+ participants is likely due to neuroinflammation. The correlation between FW and NfL, and the improvement in both FW and NfL after 12 weeks of cART treatment further reinforces this conclusion. The longer follow-up at 1 and 2 years suggests that cART helped control neuroinflammation as inferred by FW. Therefore, FW could be used as a biomarker to monitor HIV-associated neuroinflammation.
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15
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Comparison of [11C]-PBR28 Binding Between Persons Living With HIV and HIV-Uninfected Individuals. J Acquir Immune Defic Syndr 2021; 85:244-251. [PMID: 32658129 DOI: 10.1097/qai.0000000000002435] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Despite combined antiretroviral therapy, neuroinflammation may persist in persons living with HIV (PLWH) and contribute to cognitive impairment in this population. Positron emission tomography (PET) imaging targeting 18 kDa translocator protein (TSPO) has been used to localize neuroinflammation. We aimed to use TSPO-PET imaging to evaluate neuroinflammation in PLWH. DESIGN Twenty-four virologically suppressed PLWH on combined antiretroviral therapy and 13 HIV-negative (HIV-) controls completed TSPO-PET imaging using the radiotracer [C]PBR28. Because of tracer complexity and differing procedures used in previous studies, we employed an expansive methodological approach, using binding potential (BP) and standard uptake value ratio and multiple different reference regions to estimate [C]PBR28 binding. METHODS [C]PBR28 binding was measured in 30 cortical and subcortical regions and compared between PLWH and HIV- controls. Pearson correlation evaluated the association between [C]PBR28 binding and cognition and clinical measures of HIV. RESULTS Analyses conducted using multiple reference regions and measures of tracer uptake revealed no significant differences between [C]PBR28 binding in PLWH compared with HIV- controls. In addition, [C]PBR28 binding in PLWH was not significantly associated with clinical measures of HIV or plasma biomarkers of inflammation. [C]PBR28 binding was not significantly elevated in cognitively impaired PLWH compared with unimpaired PLWH, but there were inverse relationships between cognitive performance (executive and global function) and [C]PBR28 binding in PLWH. CONCLUSIONS Our results suggest that neuroinflammation may play a role in cognitive deficits, but overall neuroinflammatory levels as measured by TSPO-PET imaging in PLWH are not significantly different from those seen in HIV- controls.
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Boerwinkle AH, Meeker KL, Luckett P, Ances BM. Neuroimaging the Neuropathogenesis of HIV. Curr HIV/AIDS Rep 2021; 18:221-228. [PMID: 33630240 DOI: 10.1007/s11904-021-00548-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW This review highlights neuroimaging studies of HIV conducted over the last 2 years and discusses how relevant findings further our knowledge of the neuropathology of HIV. Three major avenues of neuroimaging research are covered with a particular emphasis on inflammation, aging, and substance use in persons living with HIV (PLWH). RECENT FINDINGS Neuroimaging has been a critical tool for understanding the neuropathological underpinnings observed in HIV. Recent studies comparing levels of neuroinflammation in PLWH and HIV-negative controls show inconsistent results but report an association between elevated neuroinflammation and poorer cognition in PLWH. Other recent neuroimaging studies suggest that older PLWH are at increased risk for brain and cognitive compromise compared to their younger counterparts. Finally, recent findings also suggest that the effects of HIV may be exacerbated by alcohol and drug abuse. These neuroimaging studies provide insight into the structural, functional, and molecular changes occurring in the brain due to HIV. HIV triggers a strong neuroimmune response and may lead to a cascade of events including increased chronic inflammation and cognitive decline. These outcomes are further exacerbated by age and age-related comorbidities, as well as lifestyle factors such as drug use/abuse.
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Affiliation(s)
- Anna H Boerwinkle
- Department of Neurology, Washington University in St. Louis, School of Medicine, Campus Box 8111, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Karin L Meeker
- Department of Neurology, Washington University in St. Louis, School of Medicine, Campus Box 8111, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Patrick Luckett
- Department of Neurology, Washington University in St. Louis, School of Medicine, Campus Box 8111, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Beau M Ances
- Department of Neurology, Washington University in St. Louis, School of Medicine, Campus Box 8111, 660 South Euclid Avenue, St. Louis, MO, 63110, USA.
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17
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Goud NS, Bhattacharya A, Joshi RK, Nagaraj C, Bharath RD, Kumar P. Carbon-11: Radiochemistry and Target-Based PET Molecular Imaging Applications in Oncology, Cardiology, and Neurology. J Med Chem 2021; 64:1223-1259. [PMID: 33499603 DOI: 10.1021/acs.jmedchem.0c01053] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The positron emission tomography (PET) molecular imaging technique has gained its universal value as a remarkable tool for medical diagnosis and biomedical research. Carbon-11 is one of the promising radiotracers that can report target-specific information related to its pharmacology and physiology to understand the disease status. Currently, many of the available carbon-11 (t1/2 = 20.4 min) PET radiotracers are heterocyclic derivatives that have been synthesized using carbon-11 inserted different functional groups obtained from primary and secondary carbon-11 precursors. A spectrum of carbon-11 PET radiotracers has been developed against many of the upregulated and emerging targets for the diagnosis, prognosis, prediction, and therapy in the fields of oncology, cardiology, and neurology. This review focuses on the carbon-11 radiochemistry and various target-specific PET molecular imaging agents used in tumor, heart, brain, and neuroinflammatory disease imaging along with its associated pathology.
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Affiliation(s)
- Nerella Sridhar Goud
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Ahana Bhattacharya
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Raman Kumar Joshi
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Rose Dawn Bharath
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Pardeep Kumar
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
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18
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Kreisl WC, Kim MJ, Coughlin JM, Henter ID, Owen DR, Innis RB. PET imaging of neuroinflammation in neurological disorders. Lancet Neurol 2020; 19:940-950. [PMID: 33098803 PMCID: PMC7912433 DOI: 10.1016/s1474-4422(20)30346-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/06/2020] [Accepted: 08/21/2020] [Indexed: 12/11/2022]
Abstract
A growing need exists for reliable in-vivo measurement of neuroinflammation to better characterise the inflammatory processes underlying various diseases and to inform the development of novel therapeutics that target deleterious glial activity. PET is well suited to quantify neuroinflammation and has the potential to discriminate components of the neuroimmune response. However, there are several obstacles to the reliable quantification of neuroinflammation by PET imaging. Despite these challenges, PET studies have consistently identified associations between neuroimmune responses and pathophysiology in brain disorders such as Alzheimer's disease. Tissue studies have also begun to clarify the meaning of changes in PET signal in some diseases. Furthermore, although PET imaging of neuroinflammation does not have an established clinical application, novel targets are under investigation and a small but growing number of studies have suggested that this imaging modality could have a role in drug development. Future studies are needed to further improve our knowledge of the cellular mechanisms that underlie changes in PET signal, how immune response contributes to neurological disease, and how it might be therapeutically modified.
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Affiliation(s)
- William C Kreisl
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Min-Jeong Kim
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Jennifer M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Ioline D Henter
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - David R Owen
- Department of Brain Sciences, Imperial College London, London, UK
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA.
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19
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Mahmud FJ, Du Y, Greif E, Boucher T, Dannals RF, Mathews WB, Pomper MG, Sysa-Shah P, Metcalf Pate KA, Lyons C, Carlson B, Chacona M, Brown AM. Osteopontin/secreted phosphoprotein-1 behaves as a molecular brake regulating the neuroinflammatory response to chronic viral infection. J Neuroinflammation 2020; 17:273. [PMID: 32943056 PMCID: PMC7499959 DOI: 10.1186/s12974-020-01949-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 09/03/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Osteopontin (OPN) as a secreted signaling protein is dramatically induced in response to cellular injury and neurodegeneration. Microglial inflammatory responses in the brain are tightly associated with the neuropathologic hallmarks of neurodegenerative disease, but understanding of the molecular mechanisms remains in several contexts poorly understood. METHODS Micro-positron emission tomography (PET) neuroimaging using radioligands to detect increased expression of the translocator protein (TSPO) receptor in the brain is a non-invasive tool used to track neuroinflammation in living mammals. RESULTS In humanized, chronically HIV-infected female mice in which OPN expression was knocked down with functional aptamers, uptake of TSPO radioligand DPA-713 was markedly upregulated in the cortex, olfactory bulb, basal forebrain, hypothalamus, and central grey matter compared to controls. Microglia immunoreactive for Iba-1 were more abundant in some HIV-infected mice, but overall, the differences were not significant between groups. TSPO+ microglia were readily detected by immunolabeling of post-mortem brain tissue and unexpectedly, two types of neurons also selectively stained positive for TSPO. The reactive cells were the specialized neurons of the cerebellum, Purkinje cells, and a subset of tyrosine hydroxylase-positive neurons of the substantia nigra. CONCLUSIONS In female mice with wild-type levels of osteopontin, increased levels of TSPO ligand uptake in the brain was seen in animals with the highest levels of persistent HIV replication. In contrast, in mice with lower levels of osteopontin, the highest levels of TSPO uptake was seen, in mice with relatively low levels of persistent infection. These findings suggest that osteopontin may act as a molecular brake regulating in the brain, the inflammatory response to HIV infection.
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Affiliation(s)
- Farina J Mahmud
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Yong Du
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Elizabeth Greif
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Thomas Boucher
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Robert F Dannals
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - William B Mathews
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Martin G Pomper
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Polina Sysa-Shah
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Kelly A Metcalf Pate
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Claire Lyons
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Bess Carlson
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Maria Chacona
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Amanda M Brown
- Department of Neurology and Neuroscience, Baltimore, USA.
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20
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Sil S, Niu F, Chivero ET, Singh S, Periyasamy P, Buch S. Role of Inflammasomes in HIV-1 and Drug Abuse Mediated Neuroinflammaging. Cells 2020; 9:cells9081857. [PMID: 32784383 PMCID: PMC7464640 DOI: 10.3390/cells9081857] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022] Open
Abstract
Despite the effectiveness of combined antiretroviral therapy (cART) in suppressing virus replication, chronic inflammation remains one of the cardinal features intersecting HIV-1, cART, drug abuse, and likely contributes to the accelerated neurocognitive decline and aging in people living with HIV-1 (PLWH) that abuse drugs. It is also estimated that ~30–60% of PLWH on cART develop cognitive deficits associated with HIV-1-associated neurocognitive disorders (HAND), with symptomatology ranging from asymptomatic to mild, neurocognitive impairments. Adding further complexity to HAND is the comorbidity of drug abuse in PLWH involving activated immune responses and the release of neurotoxins, which, in turn, mediate neuroinflammation. Premature or accelerated aging is another feature of drug abusing PLWH on cART regimes. Emerging studies implicate the role of HIV-1/HIV-1 proteins, cART, and abused drugs in altering the inflammasome signaling in the central nervous system (CNS) cells. It is thus likely that exposure of these cells to HIV-1/HIV-1 proteins, cART, and/or abused drugs could have synergistic/additive effects on the activation of inflammasomes, in turn, leading to exacerbated neuroinflammation, ultimately resulting in premature aging referred to as “inflammaging” In this review, we summarize the current knowledge of inflammasome activation, neuroinflammation, and aging in central nervous system (CNS) cells such as microglia, astrocytes, and neurons in the context of HIV-1 and drug abuse.
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Affiliation(s)
| | | | | | | | | | - Shilpa Buch
- Correspondence: (P.P.); (S.B.); Tel.: +1-402-559-3165 (S.B.)
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21
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Brain PET Imaging: Value for Understanding the Pathophysiology of HIV-associated Neurocognitive Disorder (HAND). Curr HIV/AIDS Rep 2020; 16:66-75. [PMID: 30778853 DOI: 10.1007/s11904-019-00419-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize recent developments in PET imaging of neuropathologies underlying HIV-associated neurocognitive dysfunction (HAND). We concentrate on the recent post antiretroviral era (ART), highlighting clinical and preclinical brain PET imaging studies. RECENT FINDINGS In the post ART era, PET imaging has been used to better understand perturbations of glucose metabolism, neuroinflammation, the function of neurotransmitter systems, and amyloid/tau protein deposition in the brains of HIV-infected patients and HIV animal models. Preclinical and translational findings from those studies shed a new light on the complex pathophysiology underlying HAND. The molecular imaging capabilities of PET in neuro-HIV are great complements for structural imaging modalities. Recent and future PET imaging studies can improve our understanding of neuro-HIV and provide biomarkers of disease progress that could be used as surrogate endpoints in the evaluation of the effectiveness of potential neuroprotective therapies.
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22
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Ghura S, Gross R, Jordan-Sciutto K, Dubroff J, Schnoll R, Collman RG, Ashare RL. Bidirectional Associations among Nicotine and Tobacco Smoke, NeuroHIV, and Antiretroviral Therapy. J Neuroimmune Pharmacol 2019; 15:694-714. [PMID: 31834620 DOI: 10.1007/s11481-019-09897-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/01/2019] [Indexed: 12/12/2022]
Abstract
People living with HIV (PLWH) in the antiretroviral therapy (ART) era may lose more life-years to tobacco use than to HIV. Yet, smoking rates are more than twice as high among PLWH than the general population, contributing not just to mortality but to other adverse health outcomes, including neurocognitive deficits (neuroHIV). There is growing evidence that synergy with chronic inflammation and immune dysregulation that persists despite ART may be one mechanism by which tobacco smoking contributes to neuroHIV. This review will summarize the differential effects of nicotine vs tobacco smoking on inflammation in addition to the effects of tobacco smoke components on HIV disease progression. We will also discuss biomarkers of inflammation via neuroimaging as well as biomarkers of nicotine dependence (e.g., nicotine metabolite ratio). Tobacco smoking and nicotine may impact ART drug metabolism and conversely, certain ARTs may impact nicotine metabolism. Thus, we will review these bidirectional relationships and how they may contribute to neuroHIV and other adverse outcomes. We will also discuss the effects of tobacco use on the interaction between peripheral organs (lungs, heart, kidney) and subsequent CNS function in the context of HIV. Lastly, given the dramatic rise in the use of electronic nicotine delivery systems, we will discuss the implications of vaping on these processes. Despite the growing recognition of the importance of addressing tobacco use among PLWH, more research is necessary at both the preclinical and clinical level to disentangle the potentially synergistic effects of tobacco use, nicotine, HIV, cognition and immune dysregulation, as well as identify optimal approaches to reduce tobacco use. Graphical Abstract Proposed model of the relationships among HIV, ART, smoking, inflammation, and neurocognition. Solid lines represent relationships supported by evidence. Dashed lines represent relationships for which there is not enough evidence to make a conclusion. (a) HIV infection produces elevated levels of inflammation even among virally suppressed individuals. (b) HIV is associated with deficits in cognition function. (c) Smoking rates are higher among PLWH, compared to the general population. (d) The nicotine metabolite ratio (NMR) is associated with smoking behavior. (e) HIV and tobacco use are both associated with higher rates of psychiatric comorbidities, such as depression, and elevated levels of chronic stress. These factors may represent other mechanisms linking HIV and tobacco use. (f) The relationship between nicotine, tobacco smoking, and inflammation is complex, but it is well-established that smoking induces inflammation; the evidence for nicotine as anti-inflammatory is supported in some studies, but not others. (g) The relationship between tobacco use and neurocognition may differ for the effects of nicotine (acute nicotine use may have beneficial effects) vs. tobacco smoking (chronic use may impair cognition). (h) Elevated levels of inflammation may be associated with deficits in cognition. (i) PLWH may metabolize nicotine faster than those without HIV; the mechanism is not yet known and the finding needs validation in larger samples. We also hypothesize that if HIV-infection increases nicotine metabolism, then we should observe an attenuation effect once ART is initiated. (j) It is possible that the increase in NMR is due to ART effects on CYP2A6. (k) We hypothesize that faster nicotine metabolism may result in higher levels of inflammation since nicotine has anti-inflammatory properties.
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Affiliation(s)
- Shivesh Ghura
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert Gross
- Division of Infectious Diseases, University of Pennsylvania, Philadelphia, PA, USA.,Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA, USA
| | - Kelly Jordan-Sciutto
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jacob Dubroff
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert Schnoll
- Department of Psychiatry, University of Pennsylvania, 3535 Market Street, Suite, Philadelphia, PA, 4100, USA
| | - Ronald G Collman
- Pulmonary, Allergy and Critical Care Division, University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecca L Ashare
- Department of Psychiatry, University of Pennsylvania, 3535 Market Street, Suite, Philadelphia, PA, 4100, USA.
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Guo ML, Buch S. Neuroinflammation & pre-mature aging in the context of chronic HIV infection and drug abuse: Role of dysregulated autophagy. Brain Res 2019; 1724:146446. [PMID: 31521638 DOI: 10.1016/j.brainres.2019.146446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/29/2019] [Accepted: 09/10/2019] [Indexed: 12/15/2022]
Abstract
In the era of combined antiretroviral therapy (cART), HIV-1 infection has transformed from adeath sentenceto a manageable, chronic disease. Although the lifeexpectancy of HIV+ individuals is comparable to that of the uninfectedsubjects paradoxically, there is increased prevalence ofage-associatedcomorbidities such asatherosclerosis, diabetes, osteoporosis & neurological deficits in the context of HIV infection. Drug abuse is a commoncomorbidityofHIV infection andis often associated withincreased neurological complications. Chronic neuroinflammation (abnormal microglial and astrocyte activation) and neuronal synaptodendritic injury are the features of CNS pathology observed inHIV (+) individualsthat are takingcART & that abuse drugs. Neuroinflammation is thedrivingforceunderlying prematureaging associated with HIV (+) infection, cART and drugs of abuse. Autophagy is a highly conserved process critical for maintaining cellular homeostasis. Dysregulated autophagyhas been shown to be linked with abnormal immune responses & aging. Recent emerging evidence implicatesthe role ofHIV/HIV proteins, cART, & abused drugsin disrupting theautophagy process in brain cells such as microglia, astrocytes, and neurons. It can thus be envisioned that co-exposure of CNS cells to HIV proteins, cART and/or abused drugs couldhavesynergistic effects on theautophagy process, thereby leading to exaggerated microglial/astrocyte activation, ultimately, promotingthe aging process. Restoration of autophagic functioncould thusprovide an alternative therapeuticstrategy formitigating neuroinflammation & ameliorating the premature aging process. The current review aims to unravel the role of dysregulated autophagy in the context of single or co-exposure of microglia, astrocytes, and neurons to HIV/HIV proteins, drugs of abuse &/or cART and will also discuss the pathways involved in dysregulated autophagy-mediated neuroinflammation.
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Affiliation(s)
- Ming-Lei Guo
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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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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Kaunzner UW, Kang Y, Zhang S, Morris E, Yao Y, Pandya S, Hurtado Rua SM, Park C, Gillen KM, Nguyen TD, Wang Y, Pitt D, Gauthier SA. Quantitative susceptibility mapping identifies inflammation in a subset of chronic multiple sclerosis lesions. Brain 2019; 142:133-145. [PMID: 30561514 PMCID: PMC6308309 DOI: 10.1093/brain/awy296] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/21/2018] [Accepted: 10/03/2018] [Indexed: 12/30/2022] Open
Abstract
Chronic active multiple sclerosis lesions, characterized by a hyperintense rim of iron-enriched, activated microglia and macrophages, have been linked to greater tissue damage. Post-mortem studies have determined that chronic active lesions are primarily related to the later stages of multiple sclerosis; however, the occurrence of these lesions, and their relationship to earlier disease stages may be greatly underestimated. Detection of chronic active lesions across the patient spectrum of multiple sclerosis requires a validated imaging tool to accurately identify lesions with persistent inflammation. Quantitative susceptibility mapping provides efficient in vivo quantification of susceptibility changes related to iron deposition and the potential to identify lesions harbouring iron-laden inflammatory cells. The PET tracer 11C-PK11195 targets the translocator protein expressed by activated microglia and infiltrating macrophages. Accordingly, this study aimed to validate that lesions with a hyperintense rim on quantitative susceptibility mapping from both relapsing and progressive patients demonstrate a higher level of innate immune activation as measured on 11C-PK11195 PET. Thirty patients were enrolled in this study, 24 patients had relapsing remitting multiple sclerosis, six had progressive multiple sclerosis, and all patients had concomitant MRI with a gradient echo sequence and PET with 11C-PK11195. A total of 406 chronic lesions were detected, and 43 chronic lesions with a hyperintense rim on quantitative susceptibility mapping were identified as rim+ lesions. Susceptibility (relative to CSF) was higher in rim+ (2.42 ± 17.45 ppb) compared to rim- lesions (-14.6 ± 19.3 ppb, P < 0.0001). Among rim+ lesions, susceptibility within the rim (20.04 ± 14.28 ppb) was significantly higher compared to the core (-5.49 ± 14.44 ppb, P < 0.0001), consistent with the presence of iron. In a mixed-effects model, 11C-PK11195 uptake, representing activated microglia/macrophages, was higher in rim+ lesions compared to rim- lesions (P = 0.015). Validating our in vivo imaging results, multiple sclerosis brain slabs were imaged with quantitative susceptibility mapping and processed for immunohistochemistry. These results showed a positive translocator protein signal throughout the expansive hyperintense border of rim+ lesions, which co-localized with iron containing CD68+ microglia and macrophages. In conclusion, this study provides evidence that suggests that a hyperintense rim on quantitative susceptibility measure within a chronic lesion is a correlate for persistent inflammatory activity and that these lesions can be identified in the relapsing patients. Utilizing quantitative susceptibility measure to differentiate chronic multiple sclerosis lesion subtypes, especially chronic active lesions, would provide a method to assess the impact of these lesions on disease progression.
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Affiliation(s)
- Ulrike W Kaunzner
- Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York City, NY, USA
| | - Yeona Kang
- Department of Radiology/Nuclear Medicine, Weill Cornell Medicine, New York City, NY, USA
| | - Shun Zhang
- Cornell MRI Research Lab, New York City, NY, USA
| | - Eric Morris
- Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York City, NY, USA
| | - Yihao Yao
- Cornell MRI Research Lab, New York City, NY, USA
| | - Sneha Pandya
- Department of Radiology/Nuclear Medicine, Weill Cornell Medicine, New York City, NY, USA
| | - Sandra M Hurtado Rua
- Department of Mathematics, College of Sciences and Health Professions, Cleveland State University, Cleveland, OH, USA
| | - Calvin Park
- Yale Multiple Sclerosis Center, New Haven, CT, USA
| | | | | | - Yi Wang
- Cornell MRI Research Lab, New York City, NY, USA
| | - David Pitt
- Yale Multiple Sclerosis Center, New Haven, CT, USA
| | - Susan A Gauthier
- Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York City, NY, USA
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26
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Boerwinkle A, Ances BM. Molecular Imaging of Neuroinflammation in HIV. J Neuroimmune Pharmacol 2018; 14:9-15. [PMID: 30515624 DOI: 10.1007/s11481-018-9823-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/12/2018] [Indexed: 02/05/2023]
Abstract
The development of combined antiretroviral therapy (cART) has increased the lifespan of persons living with HIV (PLWH), with most PLWH having a normal life expectancy. While significant progress has occurred, PLWH continue to have multiple health complications, including HIV associated neurocognitive disorders (HAND). While the exact cause of HAND is not known, persistent neuroinflammation is hypothesized to be an important potential contributor. Molecular imaging using positron emission tomography (PET) can non-invasively evaluate neuroinflammation. PET radiotracers specific for increased expression of the translocator protein18kDa (TSPO) on activated microglia can detect the presence of neuroinflammation in PLWH. However, results from these studies have been inconsistent and inconclusive. Future studies are needed to address key limitations that continue to persist with these techniques before accurate conclusions can be drawn regarding the role of persistent neuroinflammation in PLWH.
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Affiliation(s)
- Anna Boerwinkle
- Department of Neurology, Washington University in Saint Louis, Box 8111, 660 South Euclid Ave, St. Louis, MO, 63110, USA
| | - Beau M Ances
- Department of Neurology, Washington University in Saint Louis, Box 8111, 660 South Euclid Ave, St. Louis, MO, 63110, USA. .,Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO, 63110, USA.
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TSPO in diverse CNS pathologies and psychiatric disease: A critical review and a way forward. Pharmacol Ther 2018; 194:44-58. [PMID: 30189290 DOI: 10.1016/j.pharmthera.2018.09.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of Translocator Protein 18 kDa (TSPO) as a clinical neuroimaging biomarker of brain injury and neuroinflammation has increased exponentially in the last decade. There has been a furious pace in the development of new radiotracers for TSPO positron emission tomography (PET) imaging and its use has now been extensively described in many neurological and mental disorders. This fast pace of research and the ever-increasing number of new laboratories entering the field often times lack an appreciation of the historical perspective of the field and introduce dogmatic, but unproven facts, related to the underlying neurobiology of the TSPO response to brain injury and neuroinflammation. Paradoxically, while in neurodegenerative disorders and in all types of CNS pathologies brain TSPO levels increase, a new observation in psychiatric disorders such as schizophrenia is decreased brain levels of TSPO measured by PET. The neurobiological bases for this new finding is currently not known, but rigorous experimental design using multiple experimental approaches and careful interpretation of results is critically important to provide the methodological and/or biological underpinnings to this new observation. This review provides a perspective of the early history of validating TSPO as a biomarker of brain injury and neuroinflammation and a critical analysis of controversial topics in the literature related to the cellular sources of the TSPO response. The latter is important in order to provide the correct interpretation of PET studies in neurodegenerative and psychiatric disorders. Furthermore, this review proposes some yet to be explored explanations to new findings in psychiatric disorders and new approaches to quantitatively assess the glial sources of the TSPO response in order to move the field forward.
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Rubin LH, Sacktor N, Creighton J, Du Y, Endres CJ, Pomper MG, Coughlin JM. Microglial activation is inversely associated with cognition in individuals living with HIV on effective antiretroviral therapy. AIDS 2018; 32:1661-1667. [PMID: 29746297 DOI: 10.1097/qad.0000000000001858] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Despite viral suppression, HIV-associated cognitive impairment persists and may be partially due to persistent immune signalling by cells of the myeloid-lineage. Here, we aimed to understand the contribution of activated microglia located in vulnerable brain regions (e.g. frontal, subcortical) of HIV-infected, virally suppressed (HIV+VS) individuals in relation to cognitive and motor function. DESIGN Twenty-one HIV+VS individuals underwent PET with [11C]DPA-713 to image the translocator protein 18 kDa (TSPO), a marker of microglial activation, and completed a comprehensive neuropsychological test battery. METHODS Multivariable linear regressions were used to examine the contribution of [11C]DPA-713 binding to cognitive performance. RESULTS Higher [11C]DPA-713 binding was associated with lower cognition among HIV+VS individuals. [11C]DPA-713 binding in middle frontal gyrus/frontal cortex, hippocampus/temporal cortex and occipital cortex was inversely associated with performance on a number of cognitive domains, including verbal memory, processing speed/attention/concentration, executive function, working memory and motor function. [C]DPA-713 binding in parietal cortex, cerebellum and thalamus was associated with only specific cognitive domains including visual construction and verbal memory. Binding was not associated with global cognitive performance. CONCLUSION The findings add to the growing body of evidence that immune-mediated brain injury may contribute to domain specific, HIV-associated, cognitive vulnerabilities despite viral suppression.
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Chen WH, Yeh HL, Tsao CW, Lien LM, Chiwaya A, Alizargar J, Bai CH. Plasma Translocator Protein Levels and Outcomes of Acute Ischemic Stroke: A Pilot Study. DISEASE MARKERS 2018; 2018:9831079. [PMID: 30034558 PMCID: PMC6033241 DOI: 10.1155/2018/9831079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/17/2023]
Abstract
Translocator protein 18 kDa (TSPO) has been used as a biomarker of brain injury and inflammation in various neurological diseases. In this study, we measured the level of TSPO in acute ischemic stroke patients and determined its association with the degree of stroke severity and its ability to predict stroke functional outcomes. In total, 38 patients with moderate to severe acute ischemic stroke were enrolled. Demographic information, cerebral risk factors, and stroke severity were examined at the baseline. The National Institutes of Health Stroke Scale, modified Rankin Scale, and Barthal Index were assessed at discharge as measures of poor functional outcomes and severe disability. The baseline fasting plasma TSPO level was assessed within 24 h after the incident stroke and during hospitalization (on days 8-10). The proportion of patients with poor functional outcomes was significantly higher in the higher-TSPO group (compared to the lower group) in terms of clinical worsening (odds ratio (OR) = 11.69, 95% confidence interval (CI) = 2.08-65.6), poor functional outcomes (OR = 10.5, 95% CI = 1.14-96.57), and severe disability (OR = 4.8, 95% CI = 1.20-19.13). Plasma TSPO may be intimately linked with disease progression and worse functional outcomes in acute ischemic stroke patients.
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Affiliation(s)
- Wen-Hung Chen
- Department of Neurology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Hsu-Ling Yeh
- Department of Neurology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Chiung-Wen Tsao
- Department of Nursing, Chung Hwa University of Medical Technology, Tainan, Taiwan
| | - Li-Ming Lien
- Department of Neurology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Arthur Chiwaya
- School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan
| | - Javad Alizargar
- School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan
| | - Chyi-Huey Bai
- School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan
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Interferon-free therapy in hepatitis C virus (HCV) monoinfected and HCV/HIV coinfected patients: effect on cognitive function, fatigue, and mental health. J Neurovirol 2018; 24:557-569. [PMID: 29785584 DOI: 10.1007/s13365-018-0647-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/27/2018] [Accepted: 04/26/2018] [Indexed: 12/13/2022]
Abstract
The efficacy and safety of interferon-free therapies for hepatitis C virus (HCV) infection have been reported. Considering the accumulating evidence for a direct central nervous system infection by HCV, we aim to evaluate the effect of direct acting antivirals (DAA) therapy on cognitive function in HCV patients. We conducted a longitudinal analysis of the cognitive performance of 22 patients (8 HCV+, 14 HCV+/HIV+) who completed neuropsychological testing at baseline and at week 12 after DAA therapy. In 20 patients, we analyzed specific attention parameters derived from an experimental testing based on the Theory of Visual Attention (TVA). Depression, fatigue, and mental health were assessed as patient reported outcomes. At baseline, 54.5% of the patients met the criteria for cognitive impairment and 40% showed impairment in TVA parameters. Follow-up analysis revealed significant improvements in the domains of visual memory/learning, executive functions, verbal fluency, processing speed, and motor skills but not in verbal learning and attention/working memory. We did not observe significant improvement in visual attention measured by TVA. Fatigue and mental health significantly improved at follow-up. Our findings indicate that successful DAA treatment leads to cognitive improvements in several domains measured by standard neuropsychological testing. The absence of improvement in TVA parameters and of significant improvement in the domain of attention/working memory might reflect the persistence of specific cognitive deficits after HCV eradication. In summary, DAA treatment seems to have a positive effect on some cognitive domains and leads to an improvement in mental health and fatigue in HCV-infected patients.
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31
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Oriolo G, Egmond E, Mariño Z, Cavero M, Navines R, Zamarrenho L, Solà R, Pujol J, Bargallo N, Forns X, Martin-Santos R. Systematic review with meta-analysis: neuroimaging in hepatitis C chronic infection. Aliment Pharmacol Ther 2018. [PMID: 29536563 DOI: 10.1111/apt.14594] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Chronic hepatitis C is considered a systemic disease because of extra-hepatic manifestations. Neuroimaging has been employed in hepatitis C virus-infected patients to find in vivo evidence of central nervous system alterations. AIMS Systematic review and meta-analysis of neuroimaging research in chronic hepatitis C treatment naive patients, or patients previously treated without sustained viral response, to study structural and functional brain impact of hepatitis C. METHODS Using PRISMA guidelines a database search was conducted from inception up until 1 May 2017 for peer-reviewed studies on structural or functional neuroimaging assessment of chronic hepatitis C patients without cirrhosis or encephalopathy, with control group. Meta-analyses were performed when possible. RESULTS The final sample comprised 25 studies (magnetic resonance spectroscopy [N = 12], perfusion weighted imaging [N = 1], positron emission tomography [N = 3], single-photon emission computed tomography [N = 4], functional connectivity in resting state [N = 1], diffusion tensor imaging [N = 2] and structural magnetic resonance imaging [N = 2]). The whole sample was of 509 chronic hepatitis C patients, with an average age of 41.5 years old and mild liver disease. A meta-analysis of magnetic resonance spectroscopy studies showed increased levels of choline/creatine ratio (mean difference [MD] 0.12, 95% confidence interval [CI] 0.06-0.18), creatine (MD 0.85, 95% CI 0.42-1.27) and glutamate plus glutamine (MD 1.67, 95% CI 0.39-2.96) in basal ganglia and increased levels of choline/creatine ratio in centrum semiovale white matter (MD 0.13, 95% CI 0.07-0.19) in chronic hepatitis C patients compared with healthy controls. Photon emission tomography studies meta-analyses did not find significant differences in PK11195 binding potential in cortical and subcortical regions of chronic hepatitis C patients compared with controls. Correlations were observed between various neuroimaging alterations and neurocognitive impairment, fatigue and depressive symptoms in some studies. CONCLUSIONS Patients with chronic hepatitis C exhibit cerebral metabolite alterations and structural or functional neuroimaging abnormalities, which sustain the hypothesis of hepatitis C virus involvement in brain disturbances.
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Affiliation(s)
- G Oriolo
- Department of Psychiatry and Psychology, Hospital Clinic, Institut d'Investigació Biomèdica Arthur Pi I Sunyer (IDIBAPS), Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), University of Barcelona, Barcelona, Spain.,Department of Medicine, Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - E Egmond
- Department of Psychiatry and Psychology, Hospital Clinic, Institut d'Investigació Biomèdica Arthur Pi I Sunyer (IDIBAPS), Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), University of Barcelona, Barcelona, Spain.,Department of Medicine, Institute of Neuroscience, University of Barcelona, Barcelona, Spain.,Department of Health and Clinical Psychology, Faculty of Psychology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Z Mariño
- Liver Unit, Hospital Clinic, IDIBAPS, Centro Investigación Biomédica en Red de Enfermedades hepáticas y digestivas, (CIBEREHD), University of Barcelona, Barcelona, Spain
| | - M Cavero
- Department of Psychiatry and Psychology, Hospital Clinic, Institut d'Investigació Biomèdica Arthur Pi I Sunyer (IDIBAPS), Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), University of Barcelona, Barcelona, Spain.,Department of Medicine, Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - R Navines
- Department of Psychiatry and Psychology, Hospital Clinic, Institut d'Investigació Biomèdica Arthur Pi I Sunyer (IDIBAPS), Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), University of Barcelona, Barcelona, Spain.,Department of Medicine, Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - L Zamarrenho
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo (USP), Ribeirão Preto (SP), Brazil
| | - R Solà
- Liver Unit, Parc de Salut Mar, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - J Pujol
- MRI Research Unit, Department of Radiology, Hospital del Mar, CIBERSAM, Barcelona, Spain
| | - N Bargallo
- Center of Diagnostic Image (CDIC), Hospital Clinic, Magnetic Resonance Image Core Facility, IDIBAPS, Barcelona, Spain
| | - X Forns
- Liver Unit, Hospital Clinic, IDIBAPS, Centro Investigación Biomédica en Red de Enfermedades hepáticas y digestivas, (CIBEREHD), University of Barcelona, Barcelona, Spain
| | - R Martin-Santos
- Department of Psychiatry and Psychology, Hospital Clinic, Institut d'Investigació Biomèdica Arthur Pi I Sunyer (IDIBAPS), Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), University of Barcelona, Barcelona, Spain.,Department of Medicine, Institute of Neuroscience, University of Barcelona, Barcelona, Spain.,Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo (USP), Ribeirão Preto (SP), Brazil
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32
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Cumming P, Burgher B, Patkar O, Breakspear M, Vasdev N, Thomas P, Liu GJ, Banati R. Sifting through the surfeit of neuroinflammation tracers. J Cereb Blood Flow Metab 2018; 38:204-224. [PMID: 29256293 PMCID: PMC5951023 DOI: 10.1177/0271678x17748786] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/26/2017] [Accepted: 11/09/2017] [Indexed: 01/09/2023]
Abstract
The first phase of molecular brain imaging of microglial activation in neuroinflammatory conditions began some 20 years ago with the introduction of [11C]-( R)-PK11195, the prototype isoquinoline ligand for translocator protein (18 kDa) (TSPO). Investigations by positron emission tomography (PET) revealed microgliosis in numerous brain diseases, despite the rather low specific binding signal imparted by [11C]-( R)-PK11195. There has since been enormous expansion of the repertoire of TSPO tracers, many with higher specific binding, albeit complicated by allelic dependence of the affinity. However, the specificity of TSPO PET for revealing microglial activation not been fully established, and it has been difficult to judge the relative merits of the competing tracers and analysis methods with respect to their sensitivity for detecting microglial activation. We therefore present a systematic comparison of 13 TSPO PET and single photon computed tomography (SPECT) tracers belonging to five structural classes, each of which has been investigated by compartmental analysis in healthy human brain relative to a metabolite-corrected arterial input. We emphasize the need to establish the non-displaceable binding component for each ligand and conclude with five recommendations for a standard approach to define the cellular distribution of TSPO signals, and to characterize the properties of candidate TSPO tracers.
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Affiliation(s)
- Paul Cumming
- School of Psychology and Counselling and IHBI, Faculty of Health, Queensland University of Technology, Brisbane, Australia
- QIMR Berghofer Institute, Brisbane, Australia
| | - Bjorn Burgher
- QIMR Berghofer Institute, Brisbane, Australia
- Metro North Mental Health Service, Brisbane, Australia
| | - Omkar Patkar
- School of Psychology and Counselling and IHBI, Faculty of Health, Queensland University of Technology, Brisbane, Australia
- QIMR Berghofer Institute, Brisbane, Australia
| | - Michael Breakspear
- QIMR Berghofer Institute, Brisbane, Australia
- Metro North Mental Health Service, Brisbane, Australia
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Paul Thomas
- Herston Imaging Research Facility, Faculty of Medicine, University of Queensland Centre for Clinical Research, Herston, Australia
| | - Guo-Jun Liu
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
- National Imaging Facility, Brain and Mind Centre and Faculty of Health Sciences, University of Sydney, Camperdown, Australia
| | - Richard Banati
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
- National Imaging Facility, Brain and Mind Centre and Faculty of Health Sciences, University of Sydney, Camperdown, Australia
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Abstract
Human immunodeficiency virus (HIV) enters the brain early after infecting humans and may remain in the central nervous system despite successful antiretroviral treatment. Many neuroimaging techniques were used to study HIV+ patients with or without opportunistic infections. These techniques assessed abnormalities in brain structures (using computed tomography, structural magnetic resonance imaging (MRI), diffusion MRI) and function (using functional MRI at rest or during a task, and perfusion MRI with or without a contrast agent). In addition, single-photon emission computed tomography with various tracers (e.g., thallium-201, Tc99-HMPAO) and positron emission tomography with various agents (e.g., [18F]-dexoyglucose, [11C]-PiB, and [11C]-TSPO tracers), were applied to study opportunistic infections or HIV-associated neurocognitive disorders. Neuroimaging provides diagnoses and biomarkers to quantitate the severity of brain injury or to monitor treatment effects, and may yield insights into the pathophysiology of HIV infection. As the majority of antiretroviral-stable HIV+ patients are living longer, age-related comorbid disorders (e.g., additional neuroinflammation, cerebrovascular disorders, or other dementias) will need to be considered. Other highly prevalent conditions, such as substance use disorders, psychiatric illnesses, and the long-term effects of combined antiretroviral therapy, all may lead to additional brain injury. Neuroimaging studies could provide knowledge regarding how these comorbid conditions impact the HIV-infected brain. Lastly, specific molecular imaging agents may be needed to assess the central nervous system viral reservoir.
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Affiliation(s)
- Linda Chang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States; Department of Medicine and Department of Neurology, John A. Burns School of Medicine, University of Hawaii, Manoa, United States.
| | - Dinesh K Shukla
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
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34
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Di Biase MA, Zalesky A, O'keefe G, Laskaris L, Baune BT, Weickert CS, Olver J, McGorry PD, Amminger GP, Nelson B, Scott AM, Hickie I, Banati R, Turkheimer F, Yaqub M, Everall IP, Pantelis C, Cropley V. PET imaging of putative microglial activation in individuals at ultra-high risk for psychosis, recently diagnosed and chronically ill with schizophrenia. Transl Psychiatry 2017; 7:e1225. [PMID: 28850113 PMCID: PMC5611755 DOI: 10.1038/tp.2017.193] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/23/2017] [Indexed: 01/22/2023] Open
Abstract
We examined putative microglial activation as a function of illness course in schizophrenia. Microglial activity was quantified using [11C](R)-(1-[2-chrorophynyl]-N-methyl-N-[1-methylpropyl]-3 isoquinoline carboxamide (11C-(R)-PK11195) positron emission tomography (PET) in: (i) 10 individuals at ultra-high risk (UHR) of psychosis; (ii) 18 patients recently diagnosed with schizophrenia; (iii) 15 patients chronically ill with schizophrenia; and, (iv) 27 age-matched healthy controls. Regional-binding potential (BPND) was calculated using the simplified reference-tissue model with four alternative reference inputs. The UHR, recent-onset and chronic patient groups were compared to age-matched healthy control groups to examine between-group BPND differences in 6 regions: dorsal frontal, orbital frontal, anterior cingulate, medial temporal, thalamus and insula. Correlation analysis tested for BPND associations with gray matter volume, peripheral cytokines and clinical variables. The null hypothesis of equality in BPND between patients (UHR, recent-onset and chronic) and respective healthy control groups (younger and older) was not rejected for any group comparison or region. Across all subjects, BPND was positively correlated to age in the thalamus (r=0.43, P=0.008, false discovery rate). No correlations with regional gray matter, peripheral cytokine levels or clinical symptoms were detected. We therefore found no evidence of microglial activation in groups of individuals at high risk, recently diagnosed or chronically ill with schizophrenia. While the possibility of 11C-(R)-PK11195-binding differences in certain patient subgroups remains, the patient cohorts in our study, who also displayed normal peripheral cytokine profiles, do not substantiate the assumption of microglial activation in schizophrenia as a regular and defining feature, as measured by 11C-(R)-PK11195 BPND.
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Affiliation(s)
- M A Di Biase
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
| | - A Zalesky
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
- Melbourne School of Engineering, The University of Melbourne, Parkville, VIC Australia
| | - G O'keefe
- Department of Molecular Imaging and Therapy, The University of Melbourne, Heidelberg, VIC Australia
- Department of Medicine, The University of Melbourne, and La Trobe University, Austin Hospital, Heidelberg, VIC, Australia
| | - L Laskaris
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
| | - B T Baune
- Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia
| | - C S Weickert
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Neuroscience Research Australia, Randwick, NSW, Australia
- Schizophrenia Research Institute, Randwick, NSW, Australia
- School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - J Olver
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
- Department of Molecular Imaging and Therapy, The University of Melbourne, Heidelberg, VIC Australia
- Department of Medicine, The University of Melbourne, and La Trobe University, Austin Hospital, Heidelberg, VIC, Australia
| | - P D McGorry
- Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, VIC, Australia
- Centre for Youth Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - G P Amminger
- Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, VIC, Australia
| | - B Nelson
- Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, VIC, Australia
| | - A M Scott
- Department of Molecular Imaging and Therapy, The University of Melbourne, Heidelberg, VIC Australia
- Department of Medicine, The University of Melbourne, and La Trobe University, Austin Hospital, Heidelberg, VIC, Australia
| | - I Hickie
- Brain & Mind Centre, The University of Sydney, Camperdown, NSW, Australia
| | - R Banati
- Medical Radiation Sciences, The University of Sydney, Camperdown, NSW, Australia
| | - F Turkheimer
- Department of Neuroimaging, King’s College London, London, UK
| | - M Yaqub
- VU University Medical Center, Amsterdam, The Netherlands
| | - I P Everall
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
- North Western Mental Health, Melbourne Health, Parkville, VIC, Australia
- Florey Institute for Neurosciences and Mental Health, Parkville, VIC, Australia
- Centre for Neural Engineering, Department of Electrical and Electronic Engineering, The University of Melbourne, Carlton South, VIC, Australia
- Cooperative Research Centre for Mental Health, Carlton, VIC, Australia
| | - C Pantelis
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
- North Western Mental Health, Melbourne Health, Parkville, VIC, Australia
- Florey Institute for Neurosciences and Mental Health, Parkville, VIC, Australia
- Centre for Neural Engineering, Department of Electrical and Electronic Engineering, The University of Melbourne, Carlton South, VIC, Australia
- Cooperative Research Centre for Mental Health, Carlton, VIC, Australia
| | - V Cropley
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC Australia
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Reduction of PK11195 uptake observed in multiple sclerosis lesions after natalizumab initiation. Mult Scler Relat Disord 2017. [PMID: 28641769 DOI: 10.1016/j.msard.2017.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The objective of this study is to longitudinally analyze the uptake of [11C]PK11195-PET in multiple sclerosis patients after 3 and 6 months of natalizumab treatment. METHODS Eighteen MS patients, starting treatment with monocloncal anti-VLA-4, were enrolled in a longitudinal PK-PET study. PK uptake was quantified by volume of distribution (VT) calculation using image-derived input function at baseline, 3 and 6 months. Pharmacokinetic quantification was done using a segmented MRI, and selected areas included white matter, gadolinium enhancing lesions, non-enhancing lesions, cortical grey matter and thalamus. VTs of lesions were calculated in reference to each patient's white matter (VT ratio=VTr), to consider physiologic variability. RESULTS Test-retest variability was stable for healthy control (HC). Quantification of PK uptake was completed in 18 patients, and baseline uptake was compared to 6-month uptake. After the start of natalizumab VTr significantly decreased in 13 individual enhancing lesions present within 5 patients (p=0.001). Moreover, VTr of the sum of non-enhancing lesions showed a moderate decrease (p=0.03). No longitudinal changes were detected in normal appearing white matter, the thalamus and cortical grey matter. CONCLUSION A reduction in PK11195 uptake was observed in both enhancing and chronic lesions after the start of natalizumab. PK11195 PET can be used as tool to assess the longitudinal change in MS lesions.
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PET brain imaging in HIV-associated neurocognitive disorders (HAND) in the era of combination antiretroviral therapy. Eur J Nucl Med Mol Imaging 2017; 44:895-902. [PMID: 28058461 DOI: 10.1007/s00259-016-3602-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
Effective combination antiretroviral therapy (cART) has lead to a significant reduction in the prevalence and incidence of central nervous system (CNS) HIV-associated brain disease, particularly CNS opportunistic infections and HIV encephalitis. Despite this, cognitive deficits in people living with HIV, also known as HIV-associated neurocognitive disorders (HAND) have become more prevalent in recent years. The pathogenesis of HAND is likely to be multifactorial, however recent evidence suggests that brain microglial activation is the most likely pathogenic mechanism. Recent developments in positron emission tomography (PET) brain neuroimaging using novel brain radioligands targeting a variety of physiological changes in the brains of HIV-positive individuals have improved our understanding of the mechanisms associated with the development of HAND. This review will highlight recent PET brain neuroimaging studies in the cART era, focusing on physiological and neurochemical changes associated with HAND in people living with HIV.
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Contoreggi C, Chrousos GP, Mascio MD. Chronic distress and the vulnerable host: a new target for HIV treatment and prevention? NEUROBEHAVIORAL HIV MEDICINE 2016; 7:53-75. [PMID: 34295195 PMCID: PMC8293862 DOI: 10.2147/nbhiv.s86309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pathologic stress (distress) disturbs immune, cardiovascular, metabolic, and behavioral homeostasis. Individuals living with HIV and those at risk are vulnerable to stress disorders. Corticotropin-releasing hormone (CRH) is critical in neuroendocrine immune regulation. CRH, a neuropeptide, is distributed in the central and peripheral nervous systems and acts principally on CRH receptor type 1 (CRHR1). CRH in the brain modulates neuropsychiatric disorders. CRH and stress modulation of immunity is two-pronged; there is a direct action on hypothalamic-pituitary-adrenal secretion of glucocorticoids and through immune organ sympathetic innervation. CRH is a central and systemic proinflammatory cytokine. Glucocorticoids and their receptors have gene regulatory actions on viral replication and cause central and systemic immune suppression. CRH and stress activation contributes to central nervous system (CNS) viral entry important in HIV-associated neurocognitive disorders and HIV-associated dementia. CNS CRH overproduction short-circuits reward, executive, and emotional control, leading to addiction, cognitive impairment, and psychiatric comorbidity. CRHR1 is an important therapeutic target for medication development. CRHR1 antagonist clinical trials have focused on psychiatric disorders with little attention paid to neuroendocrine immune disorders. Studies of those with HIV and those at risk show that concurrent stress-related disorders contribute to higher morbidity and mortality; stress-related conditions, addiction, immune dysfunction, and comorbid psychiatric illness all increase HIV transmission. Neuropsychiatric disease, chronic inflammation, and substance abuse are endemic, and chronic distress is a pathologic factor. It is being understood that stress and CRH are fundamental to neuroendocrine immunity; therapeutic interventions with existing and novel agents hold promise for restoring homeostasis, reducing morbidity and mortality for those with HIV and possibly reducing future disease transmission.
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Affiliation(s)
- Carlo Contoreggi
- Intramural Research Program (IRP), National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - George P Chrousos
- Department of Pediatrics, Aghia Sophia Children’s Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Michele Di Mascio
- AIDS Imaging Research Section, Division of Clinical Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
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Eberl S, Katsifis A, Peyronneau MA, Wen L, Henderson D, Loc'h C, Greguric I, Verschuer J, Pham T, Lam P, Mattner F, Mohamed A, Fulham MJ. Preclinical in vivo and in vitro comparison of the translocator protein PET ligands [ 18F]PBR102 and [ 18F]PBR111. Eur J Nucl Med Mol Imaging 2016; 44:296-307. [PMID: 27699720 DOI: 10.1007/s00259-016-3517-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/05/2016] [Indexed: 11/27/2022]
Abstract
PURPOSE To determine the metabolic profiles of the translocator protein ligands PBR102 and PBR111 in rat and human microsomes and compare their in vivo binding and metabolite uptake in the brain of non-human primates (Papio hamadryas) using PET-CT. METHODS In vitro metabolic profiles of PBR102 and PBR111 in rat and human liver microsomes were assessed by liquid chromatography-tandem mass spectrometry. [18F]PBR102 and [18F]PBR111 were prepared by nucleophilic substitution of their corresponding p-toluenesulfonyl precursors with [18F]fluoride. List mode PET-CT brain imaging with arterial blood sampling was performed in non-human primates. Blood plasma measurements and metabolite analysis, using solid-phase extraction, provided the metabolite profile and metabolite-corrected input functions for kinetic model fitting. Blocking and displacement PET-CT scans, using PK11195, were performed. RESULTS Microsomal analyses identified the O-de-alkylated, hydroxylated and N-de-ethyl derivatives of PBR102 and PBR111 as the main metabolites. The O-de-alkylated compounds were the major metabolites in both species; human liver microsomes were less active than those from rat. Metabolic profiles in vivo in non-human primates and previously published rat experiments were consistent with the microsomal results. PET-CT studies showed that K1 was similar for baseline and blocking studies for both radiotracers; VT was reduced during the blocking study, suggesting low non-specific binding and lack of appreciable metabolite uptake in the brain. CONCLUSIONS [18F]PBR102 and [18F]PBR111 have distinct metabolic profiles in rat and non-human primates. Radiometabolites contributed to non-specific binding and confounded in vivo brain analysis of [18F]PBR102 in rodents; the impact in primates was less pronounced. Both [18F]PBR102 and [18F]PBR111 are suitable for PET imaging of TSPO in vivo. In vitro metabolite studies can be used to predict in vivo radioligand metabolism and can assist in the design and development of better radioligands.
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Affiliation(s)
- S Eberl
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia. .,Faculty of Engineering and Information Technologies, University of Sydney, Sydney, NSW, 2006, Australia.
| | - A Katsifis
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia.,Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia
| | - M A Peyronneau
- IMIV, CEA, Inserm, Univ. Paris-Sud, CNRS, Université Paris-Saclay, CEA-SHFJ, Orsay, France
| | - L Wen
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia.,Faculty of Engineering and Information Technologies, University of Sydney, Sydney, NSW, 2006, Australia
| | - D Henderson
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia
| | - C Loc'h
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia
| | - I Greguric
- Radiochemistry and Radiotracers Platform, ANSTO, New Illawarra Road, Lucas Heights, NSW, 2234, Australia
| | - J Verschuer
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia
| | - T Pham
- Radiochemistry and Radiotracers Platform, ANSTO, New Illawarra Road, Lucas Heights, NSW, 2234, Australia
| | - P Lam
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia
| | - F Mattner
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia
| | - A Mohamed
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia
| | - M J Fulham
- Department of Molecular Imaging (PET and Nuclear Medicine), Royal Prince Alfred Hospital, Building 63, Level A7, Missenden Road, Camperdown, NSW, 2050, Australia.,Faculty of Engineering and Information Technologies, University of Sydney, Sydney, NSW, 2006, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia
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Vera JH, Guo Q, Cole JH, Boasso A, Greathead L, Kelleher P, Rabiner EA, Kalk N, Bishop C, Gunn RN, Matthews PM, Winston A. Neuroinflammation in treated HIV-positive individuals: A TSPO PET study. Neurology 2016; 86:1425-1432. [PMID: 26911637 DOI: 10.1212/wnl.0000000000002485] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/06/2015] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE To explore the effects of microglial activation on brain function and structure, and its relationship with peripheral inflammatory markers, in treated, HIV-positive individuals, using in vivo [(11)C]PBR28 PET (to measure the 18 kDa translocator protein [TSPO]). METHODS Cognitively healthy HIV-positive individuals on suppressive antiretroviral therapy and HIV-negative individuals (controls) underwent brain [(11)C]PBR28 PET and MRI. HIV-positive patients completed neuropsychological testing and CSF testing for chemokines. The concentration of bacterial ribosomal 16sDNA in plasma was measured as a marker of microbial translocation. RESULTS HIV-positive individuals showed global increases in TSPO expression compared to controls (corrected p < 0.01), with significant regional increases in the parietal (p = 0.001) and occipital (p = 0.046) lobes and in the globus pallidus (p = 0.035). TSPO binding in the hippocampus, amygdala, and thalamus were associated with poorer global cognitive performance in tasks assessing verbal and visual memory (p < 0.05). Increased TSPO binding was associated with increased brain white matter diffusion MRI mean diffusivity in HIV-positive individuals, a lower CD4/CD8 ratio, and both high pretreatment HIV RNA and plasma concentration ribosomal 16s DNA (p < 0.05). CONCLUSIONS Cognitively healthy HIV-positive individuals show evidence for a chronically activated brain innate immune response and elevated blood markers of microbial translocation despite effective control of plasma viremia. Increased brain inflammation is associated with poorer cognitive performance and white matter microstructural pathology, suggesting a possible role in cognitive impairments found in some HIV-positive patients despite effective treatment.
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Affiliation(s)
- Jaime H Vera
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK.
| | - Qi Guo
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - James H Cole
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Adriano Boasso
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Louise Greathead
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Peter Kelleher
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Eugenii A Rabiner
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Nicola Kalk
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Courtney Bishop
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Roger N Gunn
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Paul M Matthews
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
| | - Alan Winston
- From the Division of Medicine, Section of Infectious Diseases (J.H.V., A.W.), Division of Brain Sciences (J.H.C., R.N.G., P.M.M.), and Centre for Immunology and Vaccinology (A.B., L.G., P.K.), Imperial College London; Division of Medicine (J.H.V.), Brighton and Sussex Medical School; Imanova Centre for Imaging Sciences (Q.G., E.A.R., N.K., C.B., R.N.G.), London; and Chelsea and Westminster Hospital (A.B., L.G., P.K.), London, UK
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Lee DE, Yue X, Ibrahim WG, Lentz MR, Peterson KL, Jagoda EM, Kassiou M, Maric D, Reid WC, Hammoud DA. Lack of neuroinflammation in the HIV-1 transgenic rat: an [(18)F]-DPA714 PET imaging study. J Neuroinflammation 2015; 12:171. [PMID: 26377670 PMCID: PMC4574011 DOI: 10.1186/s12974-015-0390-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 09/02/2015] [Indexed: 11/29/2022] Open
Abstract
Background HIV-associated neuroinflammation is believed to be a major contributing factor in the development of HIV-associated neurocognitive disorders (HAND). In this study, we used micropositron emission tomography (PET) imaging to quantify neuroinflammation in HIV-1 transgenic rat (Tg), a small animal model of HIV, known to develop neurological and behavioral problems. Methods Dynamic [18F]DPA-714 PET imaging was performed in Tg and age-matched wild-type (WT) rats in three age groups: 3-, 9-, and 16-month-old animals. As a positive control for neuroinflammation, we performed unilateral intrastriatal injection of quinolinic acid (QA) in a separate group of WT rats. To confirm our findings, we performed multiplex immunofluorescent staining for Iba1 and we measured cytokine/chemokine levels in brain lysates of Tg and WT rats at different ages. Results [18F]DPA-714 uptake in HIV-1 Tg rat brains was generally higher than in age-matched WT rats but this was not statistically significant in any age group. [18F]DPA-714 uptake in the QA-lesioned rats was significantly higher ipsilateral to the lesion compared to contralateral side indicating neuroinflammatory changes. Iba1 immunofluorescence showed no significant differences in microglial activation between the Tg and WT rats, while the QA-lesioned rats showed significant activation. Finally, cytokine/chemokine levels in brain lysates of the Tg rats and WT rats were not significantly different. Conclusion Microglial activation might not be the primary mechanism for neuropathology in the HIV-1 Tg rats. Although [18F]DPA-714 is a good biomarker of neuroinflammation, it cannot be reliably used as an in vivo biomarker of neurodegeneration in the HIV-1 Tg rat. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0390-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dianne E Lee
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, 10 Center Drive, Room 1C368, Bethesda, MD, 20814-9692, USA
| | - Xuyi Yue
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Wael G Ibrahim
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, 10 Center Drive, Room 1C368, Bethesda, MD, 20814-9692, USA
| | - Margaret R Lentz
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, 10 Center Drive, Room 1C368, Bethesda, MD, 20814-9692, USA
| | - Kristin L Peterson
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, 10 Center Drive, Room 1C368, Bethesda, MD, 20814-9692, USA
| | - Elaine M Jagoda
- Molecular Imaging Program (MIP), National Cancer Institute (NCI), Bethesda, MD, USA
| | - Michael Kassiou
- Chemistry Department, The University of Sydney, Sydney, Australia
| | - Dragan Maric
- Division of Intermural Research (DIR), National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, USA
| | - William C Reid
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, 10 Center Drive, Room 1C368, Bethesda, MD, 20814-9692, USA
| | - Dima A Hammoud
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, 10 Center Drive, Room 1C368, Bethesda, MD, 20814-9692, USA.
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Solingapuram Sai KK, Gage D, Nader M, Mach RH, Mintz A. Improved Automated Radiosynthesis of [(11)C]PBR28. Sci Pharm 2015; 83:413-27. [PMID: 26839827 PMCID: PMC4727796 DOI: 10.3797/scipharm.1505-06] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/19/2015] [Indexed: 11/22/2022] Open
Abstract
Microglial activation is commonly identified by elevated levels of the 18 kDa translocator protein (TSPO) in response to several inflammatory processes. [(11)C]PBR28 is one of the most promising PET tracers to image TSPO in both human and non-human primates. In this study, we optimized the radiolabeling procedure of [(11)C]PBR28 for higher radiochemical yield, radiochemical purity, and specific activity, which can be easily translated to any automated module for clinical trials. Time-activity curves (TACs) derived from the dynamic PET imaging of male rhesus monkey brains demonstrated that [(11)C]PBR28 had suitable kinetics with radiotracer accumulation observed in the caudate, putamen, cerebellum, and frontal cortex region.
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Affiliation(s)
| | - Don Gage
- Department of Radiology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA
| | - Mike Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA
| | - Robert H Mach
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Akiva Mintz
- Department of Radiology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA
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Abstract
PURPOSE OF REVIEW HIV enters the brain after initial infection, and with time can lead to HIV-associated neurocognitive disorders (HAND). Although the introduction of combination antiretroviral therapy has reduced the more severe forms of HAND, milder forms are still highly prevalent. The 'gold standard' for HAND diagnosis remains detailed neuropsychological performance testing but additional biomarkers (including neuroimaging) may assist in early detection of HAND. RECENT FINDINGS We review the application of recently developed noninvasive MRI and PET techniques in HIV+ individuals. In particular, magnetic resonance spectroscopy may be more sensitive than conventional MRI alone in detecting HIV associated changes. Diffusion tensor imaging has become increasingly popular for assessing changes in white matter structural integrity due to HIV. Both functional MRI and PET have been limitedly performed but could provide keys for characterizing neuropathophysiologic changes due to HIV. SUMMARY It is hoped that continued progress will allow novel neuroimaging methods to be included in future HAND management guidelines.
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Coughlin JM, Wang Y, Ma S, Yue C, Kim PK, Adams AV, Roosa HV, Gage KL, Stathis M, Rais R, Rojas C, McGlothan JL, Watkins CC, Sacktor N, Guilarte TR, Zhou Y, Sawa A, Slusher BS, Caffo B, Kassiou M, Endres CJ, Pomper MG. Regional brain distribution of translocator protein using [(11)C]DPA-713 PET in individuals infected with HIV. J Neurovirol 2014; 20:219-32. [PMID: 24567030 DOI: 10.1007/s13365-014-0239-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/11/2013] [Accepted: 01/22/2014] [Indexed: 02/06/2023]
Abstract
Imaging the brain distribution of translocator protein (TSPO), a putative biomarker for glial cell activation and neuroinflammation, may inform management of individuals infected with HIV by uncovering regional abnormalities related to neurocognitive deficits and enable non-invasive therapeutic monitoring. Using the second-generation TSPO-targeted radiotracer, [(11)C]DPA-713, we conducted a positron emission tomography (PET) study to compare the brains of 12 healthy human subjects to those of 23 individuals with HIV who were effectively treated with combination antiretroviral therapy (cART). Compared to PET data from age-matched healthy control subjects, [(11)C]DPA-713 PET of individuals infected with HIV demonstrated significantly higher volume-of-distribution (VT) ratios in white matter, cingulate cortex, and supramarginal gyrus, relative to overall gray matter VT, suggesting localized glial cell activation in susceptible regions. Regional TSPO abnormalities were evident within a sub-cohort of neuro-asymptomatic HIV subjects, and an increase in the VT ratio within frontal cortex was specifically linked to individuals affected with HIV-associated dementia. These findings were enabled by employing a gray matter normalization approach for PET data quantification, which improved test-retest reproducibility, intra-class correlation within the healthy control cohort, and sensitivity of uncovering abnormal regional findings.
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Affiliation(s)
- Jennifer M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
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Whole body biodistribution and radiation dosimetry in humans of a new PET ligand, [(18)F]-FEPPA, to image translocator protein (18 kDa). Mol Imaging Biol 2014; 15:353-9. [PMID: 22895910 DOI: 10.1007/s11307-012-0589-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE [(18)F]-FEPPA is a translocator protein (18 kDa, TSPO) positron emission tomography (PET) radiotracer. Radiation dosimetry was estimated from the whole body biodistribution, taking into consideration TSPO rs6971 (Ala147Thr) polymorphism. PROCEDURES [(18)F]-FEPPA whole body PET scans were acquired for six healthy subjects. Time-activity curves were generated from regions of interest of nine organs, from which normalized accumulated activities were calculated and thus internal dose, using OLINDA/EXM 1.1. Genotyping of rs6971, associated with high- and low-affinity [(18)F]-FEPPA binding (high-affinity binder (HAB) and low-affinity binder (LAB)), was performed. RESULTS Five subjects exhibited the C/C (HAB) allele, and the other carried the minor allele T/T (LAB). The LAB whole body biodistribution showed highest radioactivity accumulation in bladder, whereas in HABs, the spleen received the highest dose. The effective dose of the single LAB (16.3 μSv/MBq) was 23 % less than the mean of the HABs (21.0 ± 2.9 μSv/MBq). When including all subjects, the effective dose was 20.2 ± 3.0 μSv/MBq. CONCLUSIONS [(18)F]-FEPPA radiation dose is consistent with other (18)F-labeled radioligands and the Ala147Thr genotype agreed with [(18)F]-FEPPA distribution.
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Abstract
BACKGROUND Neuroinflammation plays an important role in HIV-associated neurological disorders; however, its role prior to the onset of symptomatic disease is unclear. We imaged microglial activation, the hallmark of neuroinflammation, in asymptomatic HIV-infected patients on effective combination ART. METHODS Seven neurologically and cognitively asymptomatic adults with chronic HIV-infection and nine healthy volunteers were investigated with [11C]-PK11195 PET, a marker of translocator protein (TSPO) expressed by activated microglia. In the HIV-infected patients, cognitive speed, accuracy and executive function were also assessed. Between-group differences in [11C]-PK11195 binding potential were localized throughout the brain with statistical parametric mapping (SPM) and associations between levels of [11C]-PK11195 binding and cognitive performance were interrogated using linear regression modelling. RESULTS In HIV-infected patients, Statistical parametric mapping detected clusters of significantly increased [11C]-PK11195 binding in corpus callosum (P = 0.001), anterior cingulate (P = 0.001), posterior cingulate (P = 0.008) and temporal (P = 0.026) and frontal (P = 0.038) areas. Cognitive functions were intact in the HIV group, however, a significant association between greater [11C]-PK11195 binding and poorer executive function performance was observed in the anterior cingulate (P = 0.031), corpus callosum and posterior cingulate (P = 0.001). CONCLUSION Despite effective control of HIV infection, neuroinflammation, as evidenced by the presence of focal cortical areas of activated microglia, occurs in asymptomatic HIV-infected patients and levels correlate with poorer executive performance. Further studies are needed to establish whether detection of activated microglia in HIV-infected patients represents a marker of future neurocognitive decline.
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Watkins CC, Sawa A, Pomper MG. Glia and immune cell signaling in bipolar disorder: insights from neuropharmacology and molecular imaging to clinical application. Transl Psychiatry 2014; 4:e350. [PMID: 24448212 PMCID: PMC3905229 DOI: 10.1038/tp.2013.119] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 10/28/2013] [Accepted: 11/07/2013] [Indexed: 12/27/2022] Open
Abstract
Bipolar disorder (BD) is a debilitating mental illness characterized by severe fluctuations in mood, sleep, energy and executive functioning. Pharmacological studies of selective serotonin reuptake inhibitors and the monoamine system have helped us to clinically understand bipolar depression. Mood stabilizers such as lithium and valproic acid, the first-line treatments for bipolar mania and depression, inhibit glycogen synthase kinase-3 beta (GSK-3β) and regulate the Wnt pathway. Recent investigations suggest that microglia, the resident immune cells of the brain, provide a physiological link between the serotonin system and the GSK-3β/Wnt pathway through neuroinflammation. We review the pharmacological, translational and brain imaging studies that support a role for microglia in regulating neurotransmitter synthesis and immune cell activation. These investigations provide a model for microglia involvement in the pathophysiology and phenotype of BD that may translate into improved therapies.
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Affiliation(s)
- C C Watkins
- Department of Psychiatry and Behavioral Sciences, John Hopkins University School of Medicine, Baltimore, MD, USA,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Phipps 300, Baltimore, MD 21287-0005, USA. E-mail:
| | - A Sawa
- Department of Psychiatry and Behavioral Sciences, John Hopkins University School of Medicine, Baltimore, MD, USA
| | - M G Pomper
- Department of Psychiatry and Behavioral Sciences, John Hopkins University School of Medicine, Baltimore, MD, USA,Division of Neuroradiology, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Nakamoto BK, Shikuma CM, Ogata-Arakaki D, Umaki T, Neuwelt EA, Shiramizu BT, Chow DC, Parikh NI, Kallianpur KJ, Hamilton BE. Feasibility and potential role of ferumoxytol-enhanced neuroimaging in HIV-associated neurocognitive disorder. J Neurovirol 2013; 19:601-5. [PMID: 24129909 DOI: 10.1007/s13365-013-0213-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 09/16/2013] [Accepted: 10/01/2013] [Indexed: 11/26/2022]
Abstract
We assessed ferumoxytol-enhanced brain MRI to identify monocyte/macrophage accumulation in HIV-associated neurocognitive disorder (HAND). Four HIV-infected subjects with undetectable HIV RNA levels on antiretroviral therapy, HIV DNA level in CD14+ cells ≥10 copies/10(6) cells, and cognitive impairment underwent ferumoxytol-enhanced brain MRI. On post-ferumoxytol susceptibility-weighted images, all HIV-infected subjects demonstrated a diffuse "tram track" appearance in the perivascular regions of cortical and deep white matter vessels suggesting ferumoxytol uptake in monocytes/macrophages. This finding was not present in an HIV-seronegative control. While ferumoxytol may have potential as an imaging biomarker for monocyte/macrophage accumulation in patients with HAND, future study is needed.
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Affiliation(s)
- Beau K Nakamoto
- Hawaii Center for AIDS, University of Hawaii, Honolulu, HI, USA,
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Trapani A, Palazzo C, de Candia M, Lasorsa FM, Trapani G. Targeting of the Translocator Protein 18 kDa (TSPO): A Valuable Approach for Nuclear and Optical Imaging of Activated Microglia. Bioconjug Chem 2013; 24:1415-28. [DOI: 10.1021/bc300666f] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Adriana Trapani
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | - Claudio Palazzo
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | - Modesto de Candia
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | | | - Giuseppe Trapani
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
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Berk M, Dean O, Drexhage H, McNeil JJ, Moylan S, O'Neil A, Davey CG, Sanna L, Maes M. Aspirin: a review of its neurobiological properties and therapeutic potential for mental illness. BMC Med 2013; 11:74. [PMID: 23506529 PMCID: PMC3751197 DOI: 10.1186/1741-7015-11-74] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 03/18/2013] [Indexed: 12/27/2022] Open
Abstract
There is compelling evidence to support an aetiological role for inflammation, oxidative and nitrosative stress (O&NS), and mitochondrial dysfunction in the pathophysiology of major neuropsychiatric disorders, including depression, schizophrenia, bipolar disorder, and Alzheimer's disease (AD). These may represent new pathways for therapy. Aspirin is a non-steroidal anti-inflammatory drug that is an irreversible inhibitor of both cyclooxygenase (COX)-1 and COX-2, It stimulates endogenous production of anti-inflammatory regulatory 'braking signals', including lipoxins, which dampen the inflammatory response and reduce levels of inflammatory biomarkers, including C-reactive protein, tumor necrosis factor-α and interleukin (IL)--6, but not negative immunoregulatory cytokines, such as IL-4 and IL-10. Aspirin can reduce oxidative stress and protect against oxidative damage. Early evidence suggests there are beneficial effects of aspirin in preclinical and clinical studies in mood disorders and schizophrenia, and epidemiological data suggests that high-dose aspirin is associated with a reduced risk of AD. Aspirin, one of the oldest agents in medicine, is a potential new therapy for a range of neuropsychiatric disorders, and may provide proof-of-principle support for the role of inflammation and O&NS in the pathophysiology of this diverse group of disorders.
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Affiliation(s)
- Michael Berk
- School of Medicine, Deakin University, 75 Pigdon's Road, Waurn Ponds, Geelong, Victoria 3216, Australia.
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