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Richard SA. Elucidating the pivotal molecular mechanisms, therapeutic and neuroprotective effects of lithium in traumatic brain injury. Brain Behav 2024; 14:e3595. [PMID: 38874089 PMCID: PMC11177180 DOI: 10.1002/brb3.3595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/17/2024] [Accepted: 05/26/2024] [Indexed: 06/15/2024] Open
Abstract
INTRODUCTION Traumatic brain injury (TBI) refers to damage to brain tissue by mechanical or blunt force via trauma. TBI is often associated with impaired cognitive abilities, like difficulties in memory, learning, attention, and other higher brain functions, that typically remain for years after the injury. Lithium is an elementary light metal that is only utilized in salt form due to its high intrinsic reactivity. This current review discusses the molecular mechanisms and therapeutic and neuroprotective effects of lithium in TBI. METHOD The "Boolean logic" was used to search for articles on the subject matter in PubMed and PubMed Central, as well as Google Scholar. RESULTS Lithium's therapeutic action is extremely complex, involving multiple effects on gene secretion, neurotransmitter or receptor-mediated signaling, signal transduction processes, circadian modulation, as well as ion transport. Lithium is able to normalize multiple short- as well as long-term modifications in neuronal circuits that ultimately result in disparity in cortical excitation and inhibition activated by TBI. Also, lithium levels are more distinct in the hippocampus, thalamus, neo-cortex, olfactory bulb, amygdala as well as the gray matter of the cerebellum following treatment of TBI. CONCLUSION Lithium attenuates neuroinflammation and neuronal toxicity as well as protects the brain from edema, hippocampal neurodegeneration, loss of hemispheric tissues, and enhanced memory as well as spatial learning after TBI.
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Affiliation(s)
- Seidu A Richard
- Department of Medicine, Princefield University, Ho, Ghana
- Institute of Neuroscience, Third Affiliated Hospital, Zhengzhou University, Zhengzhou, China
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2
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Savitikadi P, Palika R, Pullakhandam R, Reddy GB, Reddy SS. Dietary zinc inadequacy affects neurotrophic factors and proteostasis in the rat brain. Nutr Res 2023; 116:80-88. [PMID: 37421933 DOI: 10.1016/j.nutres.2023.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 07/10/2023]
Abstract
Zinc (Zn) deficiency has many adverse effects, including growth retardation, loss of appetite, vascular diseases, cognitive and memory impairment, and neurodegenerative diseases. In the current study, we investigated the hypothesis that dietary Zn inadequacy affects neurotrophic factors and proteostasis in the brain. Three-week-old Wistar/Kyoto male rats were fed either a Zn-deficient diet (D; < 1 mg Zn/kg diet; n = 18) or pair-fed with the control diet (C; 48 mg Zn/kg diet; n = 9) for 4 weeks. Subsequently, the rats in the D group were subdivided into two groups (n = 9), in which one group continued to receive a Zn-deficient diet, whereas the other received a Zn-supplemented diet (R; 48 mg Zn/kg diet) for 3 more weeks, after which the rats were sacrificed to collect their brain tissue. Markers of endoplasmic reticulum stress, ubiquitin-proteasome system, autophagy, and apoptosis, along with neurotrophic factors, were investigated by immunoblotting. Proteasomal activity was analyzed by the spectrofluorometric method. The results showed an altered ubiquitin-proteasome system and autophagy components and increased gliosis, endoplasmic reticulum stress, and apoptosis markers in Zn-deficient rats compared with the control group. Zinc repletion for 3 weeks could partially restore these alterations, indicating a necessity for an extended duration of Zn supplementation. In conclusion, a decline in Zn concentrations below a critical threshold may trigger multiple pathways, leading to brain-cell apoptosis.
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Affiliation(s)
- Pandarinath Savitikadi
- Biochemistry Division, ICMR - National Institute of Nutrition, Hyderabad, India, 500 007
| | - Ravindranadh Palika
- Drug Safety Division, ICMR - National Institute of Nutrition, Hyderabad, India, 500 007
| | - Raghu Pullakhandam
- Drug Safety Division, ICMR - National Institute of Nutrition, Hyderabad, India, 500 007
| | - G Bhanuprakash Reddy
- Biochemistry Division, ICMR - National Institute of Nutrition, Hyderabad, India, 500 007
| | - S Sreenivasa Reddy
- Biochemistry Division, ICMR - National Institute of Nutrition, Hyderabad, India, 500 007.
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Bouilleret V, Dedeurwaerdere S. What value can TSPO PET bring for epilepsy treatment? Eur J Nucl Med Mol Imaging 2021; 49:221-233. [PMID: 34120191 DOI: 10.1007/s00259-021-05449-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022]
Abstract
Epilepsy is one of the most common neurological disorders and affects both the young and adult populations. The question we asked for this review was how positron emission tomography (PET) imaging with translocator protein (TSPO) radioligands can help inform the epilepsy clinic and the development of future treatments targeting neuroinflammatory processes.Even though the first TSPO PET scans in epilepsy patients were performed over 20 years ago, this imaging modality has not seen wide adoption in the clinic. There is vast scientific evidence from preclinical studies in rodent models of temporal lobe epilepsy which have shown increased levels of TSPO corresponding to neuroinflammatory processes in the brain. These increases peaked sub-acutely (1-2 weeks) after the epileptogenic insult (e.g. status epilepticus) and remained chronically increased, albeit at lower levels. In addition, these studies have shown a correlation between TSPO levels and seizure outcome, pharmacoresistance and behavioural morbidities. Histological assessment points to a complex interplay between different cellular components such as microglial activation, astrogliosis and cell death changing dynamically over time.In epilepsy patients, a highly sensitive biomarker of neuroinflammation would provide value for the optimization of surgical assessment (particularly for extratemporal lobe epilepsy) and support the clinical development path of anti-inflammatory treatments. Clinical studies have shown a systematic increase in asymmetry indices of TSPO PET binding. However, region-based analysis typically does not yield statistical differences and changes are often not restricted to the epileptogenic zone, limiting the ability of this imaging modality to localise pathology for surgery. In this manuscript, we discuss the biological underpinnings of these findings and review for which applications in epilepsy TSPO PET could bring added value.
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Affiliation(s)
- Viviane Bouilleret
- Unité de Neurophysiologie et d'Epileptologie (UNCE), Université Paris-Saclay APHP, 78, Rue du Général Leclerc, 94275, Le Kremlin Bicêtre, France.
- CEA, CNRS, Inserm, BioMaps, Université Paris-Saclay, Orsay, France.
| | - Stefanie Dedeurwaerdere
- Neurosciences Therapeutic Area, Early Solutions, UCB Pharma, Braine-l'Alleud, Belgium
- Experimental Laboratory of Haematology, University of Antwerp, Wilrijk, Belgium
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Toutonji A, Mandava M, Guglietta S, Tomlinson S. Chronic complement dysregulation drives neuroinflammation after traumatic brain injury: a transcriptomic study. Acta Neuropathol Commun 2021; 9:126. [PMID: 34281628 PMCID: PMC8287781 DOI: 10.1186/s40478-021-01226-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/07/2021] [Indexed: 02/07/2023] Open
Abstract
Activation of the complement system propagates neuroinflammation and brain damage early and chronically after traumatic brain injury (TBI). The complement system is complex and comprises more than 50 components, many of which remain to be characterized in the normal and injured brain. Moreover, complement therapeutic studies have focused on a limited number of histopathological outcomes, which while informative, do not assess the effect of complement inhibition on neuroprotection and inflammation in a comprehensive manner. Using high throughput gene expression technology (NanoString), we simultaneously analyzed complement gene expression profiles with other neuroinflammatory pathway genes at different time points after TBI. We additionally assessed the effects of complement inhibition on neuropathological processes. Analyses of neuroinflammatory genes were performed at days 3, 7, and 28 post injury in male C57BL/6 mice following a controlled cortical impact injury. We also characterized the expression of 59 complement genes at similar time points, and also at 1- and 2-years post injury. Overall, TBI upregulated the expression of markers of astrogliosis, immune cell activation, and cellular stress, and downregulated the expression of neuronal and synaptic markers from day 3 through 28 post injury. Moreover, TBI upregulated gene expression across most complement activation and effector pathways, with an early emphasis on classical pathway genes and with continued upregulation of C2, C3 and C4 expression 2 years post injury. Treatment using the targeted complement inhibitor, CR2-Crry, significantly ameliorated TBI-induced transcriptomic changes at all time points. Nevertheless, some immune and synaptic genes remained dysregulated with CR2-Crry treatment, suggesting adjuvant anti-inflammatory and neurotropic therapy may confer additional neuroprotection. In addition to characterizing complement gene expression in the normal and aging brain, our results demonstrate broad and chronic dysregulation of the complement system after TBI, and strengthen the view that the complement system is an attractive target for TBI therapy.
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Affiliation(s)
- Amer Toutonji
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, BSB 204, MSC 504, Charleston, SC 29425 USA
| | - Mamatha Mandava
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, BSB 204, MSC 504, Charleston, SC 29425 USA
| | - Silvia Guglietta
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, BSB 204, MSC 504, Charleston, SC 29425 USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, BSB 204, MSC 504, Charleston, SC 29425 USA
- Ralph Johnson VA Medical Center, Charleston, SC 29401 USA
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Hiskens MI, Vella RK, Schneiders AG, Fenning AS. Minocycline improves cognition and molecular measures of inflammation and neurodegeneration following repetitive mTBI. Brain Inj 2021; 35:831-841. [PMID: 33818227 DOI: 10.1080/02699052.2021.1909139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/01/2021] [Accepted: 03/15/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To compare the neuroprotective effects of minocycline treatment in a murine model of mTBI on measures of spatial learning and memory, neuroinflammation, excitotoxicity, and neurodegeneration. DESIGN Adult male C57BL/6 J mice were randomly assigned into vehicle control, vehicle with repetitive mTBI, minocycline without mTBI, or minocycline with repetitive mTBI groups. METHODS A validated mouse model of repetitive impact-induced rotational acceleration was used to deliver 15 mTBIs across 23 days. Cognition was assessed via Morris water maze (MWM) testing, and mRNA analysis investigated MAPT, GFAP, AIF1, GRIA1, TARDBP, TNF, and NEFL genes. Assessment was undertaken 48 h and 3 months following final mTBI. RESULTS In the chronic phase of recovery, MWM testing revealed impairment in the vehicle mTBI group compared to unimpacted controls (p < .01) that was not present in the minocycline mTBI group, indicating chronic neuroprotection. mRNA analysis revealed AIF1 elevation in the acute cortex (p < .01) and chronic hippocampus (p < .01) of the vehicle mTBI group, with minocycline treatment leading to improved markers of microglial activation and inflammation in the chronic stage of recovery. CONCLUSIONS These data suggest that minocycline treatment alleviated some mTBI pathophysiology and clinical features at chronic time-points.
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Affiliation(s)
- Matthew I Hiskens
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia
| | - Rebecca K Vella
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia
| | - Anthony G Schneiders
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia
| | - Andrew S Fenning
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia
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Nikam RM, Yue X, Kandula VV, Paudyal B, Langhans SA, Averill LW, Choudhary AK. Unravelling neuroinflammation in abusive head trauma with radiotracer imaging. Pediatr Radiol 2021; 51:966-970. [PMID: 33999238 DOI: 10.1007/s00247-021-04995-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/07/2020] [Accepted: 01/27/2021] [Indexed: 01/07/2023]
Abstract
Abusive head trauma (AHT) is a leading cause of mortality and morbidity in child abuse, with a mortality rate of approximately 25%. In survivors, the prognosis remains dismal, with high prevalence of cerebral palsy, epilepsy and neuropsychiatric disorders. Early and accurate diagnosis of AHT is challenging, both clinically and radiologically, with up to one-third of cases missed on initial examination. Moreover, most of the management in AHT is supportive, reflective of the lack of clear understanding of specific pathogenic mechanisms underlying secondary insult, with approaches targeted toward decreasing intracranial hypertension and reducing cerebral metabolism, cell death and excitotoxicity. Multiple studies have elucidated the role of pro- and anti-inflammatory cytokines and chemokines with upregulation/recruitment of microglia/macrophages, oligodendrocytes and astrocytes in severe traumatic brain injury (TBI). In addition, recent studies in animal models of AHT have demonstrated significant upregulation of microglia, with a potential role of inflammatory cascade contributing to secondary insult. Despite the histological and biochemical evidence, there is a significant dearth of specific imaging approaches to identify this neuroinflammation in AHT. The primary motivation for development of such imaging approaches stems from the need to therapeutically target neuroinflammation and establish its utility in monitoring and prognostication. In the present paper, we discuss the available data suggesting the potential role of neuroinflammation in AHT and role of radiotracer imaging in aiding diagnosis and patient management.
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Affiliation(s)
- Rahul M Nikam
- Department of Medical Imaging, Nemours Alfred I. duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE, 19803, USA. .,Katzin Diagnostic & Research PET/MR Center, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
| | - Xuyi Yue
- Katzin Diagnostic & Research PET/MR Center, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Vinay V Kandula
- Department of Medical Imaging, Nemours Alfred I. duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE, 19803, USA
| | - Bishnuhari Paudyal
- Katzin Diagnostic & Research PET/MR Center, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Sigrid A Langhans
- Katzin Diagnostic & Research PET/MR Center, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Lauren W Averill
- Department of Medical Imaging, Nemours Alfred I. duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE, 19803, USA
| | - Arabinda K Choudhary
- Department of Radiology, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR, USA
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Beitchman JA, Lifshitz J, Harris NG, Thomas TC, Lafrenaye AD, Hånell A, Dixon CE, Povlishock JT, Rowe RK. Spatial Distribution of Neuropathology and Neuroinflammation Elucidate the Biomechanics of Fluid Percussion Injury. Neurotrauma Rep 2021; 2:59-75. [PMID: 34223546 PMCID: PMC8240834 DOI: 10.1089/neur.2020.0046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Diffuse brain injury is better described as multi-focal, where pathology can be found adjacent to seemingly uninjured neural tissue. In experimental diffuse brain injury, pathology and pathophysiology have been reported far more lateral than predicted by the impact site. We hypothesized that local thickening of the rodent skull at the temporal ridges serves to focus the intracranial mechanical forces experienced during brain injury and generate predictable pathology. We demonstrated local thickening of the skull at the temporal ridges using contour analysis on magnetic resonance imaging. After diffuse brain injury induced by midline fluid percussion injury (mFPI), pathological foci along the anterior-posterior length of cortex under the temporal ridges were evident acutely (1, 2, and 7 days) and chronically (28 days) post-injury by deposition of argyophilic reaction product. Area CA3 of the hippocampus and lateral nuclei of the thalamus showed pathological change, suggesting that mechanical forces to or from the temporal ridges shear subcortical regions. A proposed model of mFPI biomechanics suggests that injury force vectors reflect off the skull base and radiate toward the temporal ridge, thereby injuring ventral thalamus, dorsolateral hippocampus, and sensorimotor cortex. Surgically thinning the temporal ridge before injury reduced injury-induced inflammation in the sensorimotor cortex. These data build evidence for temporal ridges of the rodent skull to contribute to the observed pathology, whether by focusing extracranial forces to enter the cranium or intracranial forces to escape the cranium. Pre-clinical investigations can take advantage of the predicted pathology to explore injury mechanisms and treatment efficacy.
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Affiliation(s)
- Joshua A Beitchman
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Midwestern University, Glendale, Arizona, USA
| | - Jonathan Lifshitz
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Arizona State University, Tempe, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| | - Neil G Harris
- UCLA Brain Injury Research Center, Department of Neurosurgery, and Intellectual Development and Disabilities Research Center, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA
| | - Theresa Currier Thomas
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Arizona State University, Tempe, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| | | | - Anders Hånell
- Virginia Commonwealth University, Richmond, Virginia, USA.,Uppsala University Hospital, Uppsala, Sweden
| | | | | | - Rachel K Rowe
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
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Positron Emission Tomography Imaging of Long-Term Expression of the 18 kDa Translocator Protein After Sudden Cardiac Arrest in Rats. Shock 2020; 55:620-629. [PMID: 32433203 DOI: 10.1097/shk.0000000000001546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Knowledge about the neuroinflammatory state during months after sudden cardiac arrest is scarce. Neuroinflammation is mediated by cells that express the 18 kDa translocator protein (TSPO). We determined the time course of TSPO-expressing cells in a rat model of sudden cardiac arrest using longitudinal in vivo positron emission tomography (PET) imaging with the TSPO-specific tracer [18F]DAA1106 over a period of 6 months. METHODS Five male Sprague Dawley rats were resuscitated from 6 min sudden cardiac arrest due to ventricular fibrillation, three animals served as shams. PET measurements were performed on day 5, 8, 14, 90, and 180 after intervention. Magnetic resonance imaging was performed on day 140. Imaging was preceded by Barnes Maze spatial memory testing on day 3, 13, 90, and 180. Specificity of [18F]DAA1106 binding was confirmed by Iba-1 immunohistochemistry. RESULTS [18F]DAA1106 accumulated bilaterally in the dorsal hippocampus of all sudden cardiac arrest animals on all measured time points. Immunohistochemistry confirmed Iba-1 expressing cells in the hippocampal CA1 region. The number of Iba-1-immunoreactive objects per mm2 was significantly correlated with [18F]DAA1106 uptake. Additionally, two of the five sudden cardiac arrest rats showed bilateral TSPO-expression in the striatum that persisted until day 180. In Barnes Maze, the relative time spent in the target quadrant negatively correlates with dorsal hippocampal [18F]DAA1106 uptake on day 14 and 180. CONCLUSIONS After sudden cardiac arrest, TSPO remains expressed over the long-term. Sustainable treatment options for neuroinflammation may be considered to improve cognitive functions after sudden cardiac arrest.
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Dimitrova-Shumkovska J, Krstanoski L, Veenman L. Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update. Cells 2020; 9:cells9040870. [PMID: 32252470 PMCID: PMC7226777 DOI: 10.3390/cells9040870] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/30/2020] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation and cell death are among the common symptoms of many central nervous system diseases and injuries. Neuroinflammation and programmed cell death of the various cell types in the brain appear to be part of these disorders, and characteristic for each cell type, including neurons and glia cells. Concerning the effects of 18-kDa translocator protein (TSPO) on glial activation, as well as being associated with neuronal cell death, as a response mechanism to oxidative stress, the changes of its expression assayed with the aid of TSPO-specific positron emission tomography (PET) tracers' uptake could also offer evidence for following the pathogenesis of these disorders. This could potentially increase the number of diagnostic tests to accurately establish the stadium and development of the disease in question. Nonetheless, the differences in results regarding TSPO PET signals of first and second generations of tracers measured in patients with neurological disorders versus healthy controls indicate that we still have to understand more regarding TSPO characteristics. Expanding on investigations regarding the neuroprotective and healing effects of TSPO ligands could also contribute to a better understanding of the therapeutic potential of TSPO activity for brain damage due to brain injury and disease. Studies so far have directed attention to the effects on neurons and glia, and processes, such as death, inflammation, and regeneration. It is definitely worthwhile to drive such studies forward. From recent research it also appears that TSPO ligands, such as PK11195, Etifoxine, Emapunil, and 2-Cl-MGV-1, demonstrate the potential of targeting TSPO for treatments of brain diseases and disorders.
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Affiliation(s)
- Jasmina Dimitrova-Shumkovska
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
- Correspondence: (J.D.-S.); (L.V.)
| | - Ljupcho Krstanoski
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
| | - Leo Veenman
- Technion-Israel Institute of Technology, Faculty of Medicine, Rappaport Institute of Medical Research, 1 Efron Street, P.O. Box 9697, Haifa 31096, Israel
- Correspondence: (J.D.-S.); (L.V.)
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Hiskens MI, Schneiders AG, Angoa-Pérez M, Vella RK, Fenning AS. Blood biomarkers for assessment of mild traumatic brain injury and chronic traumatic encephalopathy. Biomarkers 2020; 25:213-227. [PMID: 32096416 DOI: 10.1080/1354750x.2020.1735521] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mild traumatic brain injuries (mTBI) are prevalent and can result in significant debilitation. Current diagnostic methods have implicit limitations, with clinical assessment tools reliant on subjective self-reported symptoms or non-specific clinical observations, and commonly available imaging techniques lacking sufficient sensitivity to detect mTBI. A blood biomarker would provide a readily accessible detector of mTBI to meet the current measurement gap. Suitable options would provide objective and quantifiable information in diagnosing mTBI, in monitoring recovery, and in establishing a prognosis of resultant neurodegenerative disease, such as chronic traumatic encephalopathy (CTE). A biomarker would also assist in progressing research, providing suitable endpoints for testing therapeutic modalities and for further exploring mTBI pathophysiology. This review highlights the most promising blood-based protein candidates that are expressed in the central nervous system (CNS) and released into systemic circulation following mTBI. To date, neurofilament light (NF-L) may be the most suitable candidate for assessing neuronal damage, and glial fibrillary acidic protein (GFAP) for assessing astrocyte activation, although further work is required. Ultimately, the heterogeneity of cells in the brain and each marker's limitations may require a combination of biomarkers, and recent developments in microRNA (miRNA) markers of mTBI show promise and warrant further exploration.
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Affiliation(s)
- Matthew I Hiskens
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Australia
| | - Anthony G Schneiders
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Australia
| | - Mariana Angoa-Pérez
- Research and Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA.,Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Rebecca K Vella
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Australia
| | - Andrew S Fenning
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Australia
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11
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Yasmin A, Pitkänen A, Jokivarsi K, Poutiainen P, Gröhn O, Immonen R. MRS Reveals Chronic Inflammation in T2w MRI-Negative Perilesional Cortex - A 6-Months Multimodal Imaging Follow-Up Study. Front Neurosci 2019; 13:863. [PMID: 31474824 PMCID: PMC6707062 DOI: 10.3389/fnins.2019.00863] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/31/2019] [Indexed: 12/14/2022] Open
Abstract
Sustained inflammation in the injured cortex is a promising therapeutic target for disease-modification after traumatic brain injury (TBI). However, its extent and dynamics of expansion are incompletely understood which challenges the timing and placement of therapeutics to lesioned area. Our aim was to characterize the evolution of chronic inflammation during lesion expansion in lateral fluid-percussion injury (FPI) rat model with focus on the MRI-negative perilesional cortex. T2-weighted MR imaging (T2w MRI) and localized magnetic resonance spectroscopy (MRS) were performed at 1, 3, and 6 months post-injury. End-point histology, including Nissl for neuronal death, GFAP for astrogliosis, and Prussian Blue for iron were used to assess perilesional histopathology. An additional animal cohort was imaged with a positron emission tomography (PET) using translocator protein 18 kDa (TSPO) radiotracer [18F]-FEPPA. T2w MRI assessed lesion growth and detected chronic inflammation along the lesion border while rest of the ipsilateral cortex was MRI-negative (MRI-). Instead, myo-inositol that is an inflammatory MRS marker for gliosis, glutathione for oxidative stress, and choline for membrane turnover were elevated throughout the 6-months follow-up in the MRI- perilesional cortex (all p < 0.05). MRS markers revealed chronically sustained inflammation across the ipsilateral cortex but did not indicate the upcoming lesion expansion. Instead, the rostral expansion of the cortical lesion was systematically preceded by a hyperintense band in T2w images months earlier. Histologic analysis of the hyperintensity indicated scattered astrocytes, incomplete glial scar, and intracellularly packed and free iron. Yet, the band was negative in [18F]-FEPPA-PET. [18F]-FEPPA also showed no cortical TSPO expression within the MRS voxel in MRI- perilesional cortex or anywhere along glial scar when assessed at 2 months post-injury. However, [18F]-FEPPA showed a robust signal increase, indicating reactive microgliosis in the ipsilateral thalamus at 2 months post-TBI. We present evidence that MRS reveals chronic posttraumatic inflammation in MRI-negative perilesional cortex. The mismatch in MRS, MRI, and PET measures may allow non-invasive endophenotyping of beneficial and detrimental inflammatory processes to aid targeting and timing of anti-inflammatory therapeutics.
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Affiliation(s)
- Amna Yasmin
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Asla Pitkänen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Kimmo Jokivarsi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Pekka Poutiainen
- Center of Diagnostic Imaging, Department of Cyclotron and Radiopharmacy, Kuopio University Hospital, Kuopio, Finland
| | - Olli Gröhn
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Riikka Immonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
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12
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18F-PBR06 PET/CT imaging for evaluating atherosclerotic plaques linked to macrophage infiltration. Nucl Med Commun 2019; 40:370-376. [PMID: 30875334 DOI: 10.1097/mnm.0000000000000978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND The present study explored the 18 kDa translocator protein radioligand [F]N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline (F-PBR06) targeting macrophages for PET imaging of atherosclerotic plaques and evaluating the vulnerability of atherosclerotic plaques toward rupture. MATERIALS AND METHODS F-PBR06 was synthesized using a Synthra RNplus module automatically. RAW264.7 cells were used for cell binding study with F-PBR06. In-vivo micro-PET/CT imaging for ApoE mice and C57 mice was performed 1 h after injection of F-PBR06. CD68 and F480 immunofluorescence stainings were performed in the aorta tissues. RESULTS In-vitro cell studies showed uptake of F-PBR06 to RAW264.7 cells. Micro-PET/CT imaging identified the atherosclerotic lesions in the aortic arch of ApoE mice successfully, whereas no signal was observed in C57 mice. The ratio of plaque-to-muscle in ApoE mice of 32 weeks was significantly higher than that in ApoE mice of 22 weeks, which was confirmed by CD68 immunofluorescence staining and F480 immunofluorescence staining. CONCLUSION TSPO radioligand F-PBR06 allows noninvasive PET/CT imaging of macrophage-abundant atherosclerotic plaques as well as positive correlation between PET imagings and ex-vivo immunofluorescence staining of plaques in mice with different ages, thereby representing a potential attractive tool for evaluating the vulnerability of atherosclerotic plaques towards rupture.
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Imaging biomarkers of epileptogenecity after traumatic brain injury - Preclinical frontiers. Neurobiol Dis 2018; 123:75-85. [PMID: 30321600 DOI: 10.1016/j.nbd.2018.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/04/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023] Open
Abstract
Posttraumatic epilepsy (PTE) is a major neurodegenerative disease accounting for 20% of symptomatic epilepsy cases. A long latent phase offers a potential window for prophylactic treatment strategies to prevent epilepsy onset, provided that the patients at risk can be identified. Some promising imaging biomarker candidates for posttraumatic epileptogenesis have been identified, but more are required to provide the specificity and sensitivity for accurate prediction. Experimental models and preclinical longitudinal, multimodal imaging studies allow follow-up of complex cascade of events initiated by traumatic brain injury, as well as monitoring of treatment effects. Preclinical imaging data from the posttraumatic brain are rich in information, yet examination of their specific relevance to epilepsy is lacking. Accumulating evidence from ongoing preclinical studies in TBI support insight into processes involved in epileptogenesis, e.g. inflammation and changes in functional and structural brain-wide connectivity. These efforts are likely to produce both new biomarkers and treatment targets for PTE.
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Missault S, Anckaerts C, Blockx I, Deleye S, Van Dam D, Barriche N, De Pauw G, Aertgeerts S, Valkenburg F, De Deyn PP, Verhaeghe J, Wyffels L, Van der Linden A, Staelens S, Verhoye M, Dedeurwaerdere S. Neuroimaging of Subacute Brain Inflammation and Microstructural Changes Predicts Long-Term Functional Outcome after Experimental Traumatic Brain Injury. J Neurotrauma 2018; 36:768-788. [PMID: 30032713 DOI: 10.1089/neu.2018.5704] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
There is currently a lack of prognostic biomarkers to predict the different sequelae following traumatic brain injury (TBI). The present study investigated the hypothesis that subacute neuroinflammation and microstructural changes correlate with chronic TBI deficits. Rats were subjected to controlled cortical impact (CCI) injury, sham surgery, or skin incision (naïve). CCI-injured (n = 18) and sham-operated rats (n = 6) underwent positron emission tomography (PET) imaging with the translocator protein 18 kDa (TSPO) radioligand [18F]PBR111 and diffusion tensor imaging (DTI) in the subacute phase (≤3 weeks post-injury) to quantify inflammation and microstructural alterations. CCI-injured, sham-operated, and naïve rats (n = 8) underwent behavioral testing in the chronic phase (5.5-10 months post-injury): open field and sucrose preference tests, two one-week video-electroencephalogram (vEEG) monitoring periods, pentylenetetrazole (PTZ) seizure susceptibility tests, and a Morris water maze (MWM) test. In vivo imaging revealed pronounced neuroinflammation, decreased fractional anisotropy, and increased diffusivity in perilesional cortex and ipsilesional hippocampus of CCI-injured rats. Behavioral analysis revealed disinhibition, anhedonia, increased seizure susceptibility, and impaired learning in CCI-injured rats. Subacute TSPO expression and changes in DTI metrics significantly correlated with several chronic deficits (Pearson's |r| = 0.50-0.90). Certain specific PET and DTI parameters had good sensitivity and specificity (area under the receiver operator characteristic [ROC] curve = 0.85-1.00) to distinguish between TBI animals with and without particular behavioral deficits. Depending on the investigated behavioral deficit, PET or DTI data alone, or the combination, could very well predict the variability in functional outcome data (adjusted R2 = 0.54-1.00). Taken together, both TSPO PET and DTI seem promising prognostic biomarkers to predict different chronic TBI sequelae.
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Affiliation(s)
- Stephan Missault
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium .,2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Cynthia Anckaerts
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Ines Blockx
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Steven Deleye
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Debby Van Dam
- 4 Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen (UMCG) , Groningen, The Netherlands
| | - Nora Barriche
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Glenn De Pauw
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Stephanie Aertgeerts
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Femke Valkenburg
- 4 Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen (UMCG) , Groningen, The Netherlands
| | - Peter Paul De Deyn
- 4 Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen (UMCG) , Groningen, The Netherlands
| | - Jeroen Verhaeghe
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Leonie Wyffels
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium .,5 Department of Nuclear Medicine, University Hospital Antwerp , Edegem, Belgium
| | - Annemie Van der Linden
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Steven Staelens
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Marleen Verhoye
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Stefanie Dedeurwaerdere
- 6 Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
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Xiong Y, Mahmood A, Chopp M. Current understanding of neuroinflammation after traumatic brain injury and cell-based therapeutic opportunities. Chin J Traumatol 2018; 21:137-151. [PMID: 29764704 PMCID: PMC6034172 DOI: 10.1016/j.cjtee.2018.02.003] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 02/04/2023] Open
Abstract
Traumatic brain injury (TBI) remains a major cause of death and disability worldwide. Increasing evidence indicates that TBI is an important risk factor for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and chronic traumatic encephalopathy. Despite improved supportive and rehabilitative care of TBI patients, unfortunately, all late phase clinical trials in TBI have yet to yield a safe and effective neuroprotective treatment. The disappointing clinical trials may be attributed to variability in treatment approaches and heterogeneity of the population of TBI patients as well as a race against time to prevent or reduce inexorable cell death. TBI is not just an acute event but a chronic disease. Among many mechanisms involved in secondary injury after TBI, emerging preclinical studies indicate that posttraumatic prolonged and progressive neuroinflammation is associated with neurodegeneration which may be treatable long after the initiating brain injury. This review provides an overview of recent understanding of neuroinflammation in TBI and preclinical cell-based therapies that target neuroinflammation and promote functional recovery after TBI.
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Affiliation(s)
- Ye Xiong
- Department of Neurosurgery Henry Ford Health System, 2799 West Grand Boulevard, Detroit, MI, 48202, USA.
| | - Asim Mahmood
- Department of Neurosurgery Henry Ford Health System, 2799 West Grand Boulevard, Detroit, MI, 48202, USA
| | - Michael Chopp
- Department of Neurology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, MI, 48202, USA; Department of Physics, Oakland University, Rochester, MI, 48309, USA
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16
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McNeela AM, Bernick C, Hines RM, Hines DJ. TSPO regulation in reactive gliotic diseases. J Neurosci Res 2018; 96:978-988. [PMID: 29315754 DOI: 10.1002/jnr.24212] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 11/29/2017] [Accepted: 12/06/2017] [Indexed: 12/19/2022]
Abstract
The brain is the most metabolically active organ in the body. This high metabolic demand is apparent in that 60% of the brain is comprised of mitochondria-enriched cells. A disruption of the brain's ability to meet this immense metabolic demand is central to the pathogenesis of a multitude of neurological disorders, which range from depression to Alzheimer's disease. Central to these pathologies are glial signaling and energy metabolism cascades regulating apoptosis and inflammation. Thus, diseases causing inflammation and disruption of metabolism can be correlated with glial reactivity. Acutely, reactive gliosis provides a mechanism for limiting the progression of a disease. Following chronic activation, the ability of reactive gliosis to limit disease progression decreases and, in some cases, transitions into a harmful state. The necessity for a noninvasive biomarker of disease in the brain has linked reactive gliosis with an upregulation of translocator protein (TSPO). TSPO is an 18kDa protein that is both a therapeutic target for multiple acute and chronic neuroinflammatory diseases and the leading biomarker for Alzheimer's disease. Although a central function of TSPO is not well known, the protein was named for its ability to translocate cholesterol. Increased TSPO expression is an indicator of disrupted metabolic activity and increased reactive oxygen production. The changes in TSPO expression levels both temporally and spatially relate to the pathogenesis of stroke, Alzheimer's disease, traumatic brain injury, and depression. Therefore, research into the basic function and potential therapeutics targeting TSPO will have broad implications for many diseases of the brain.
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Affiliation(s)
- Adam M McNeela
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV
| | - Charles Bernick
- Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV
| | - Rochelle M Hines
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV
| | - Dustin J Hines
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV
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Effect of Cigarette Smoking on a Marker for Neuroinflammation: A [ 11C]DAA1106 Positron Emission Tomography Study. Neuropsychopharmacology 2017; 42:1630-1639. [PMID: 28262740 PMCID: PMC5518907 DOI: 10.1038/npp.2017.48] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/01/2017] [Accepted: 02/23/2017] [Indexed: 01/21/2023]
Abstract
In the brain, microglia continuously scan the surrounding extracellular space in order to respond to damage or infection by becoming activated and participating in neuroinflammation. When activated, microglia increase the expression of translocator protein (TSPO) 18 kDa, thereby making the TSPO expression a marker for neuroinflammation. We used the radiotracer [11C]DAA1106 (a ligand for TSPO) and positron emission tomography (PET) to determine the effect of smoking on availability of this marker for neuroinflammation. Forty-five participants (30 smokers and 15 non-smokers) completed the study and had usable data. Participants underwent a dynamic PET scanning session with bolus injection of [11C]DAA1106 (with smokers in the satiated state) and blood draws during PET scanning to determine TSPO affinity genotype and plasma nicotine levels. Whole-brain standardized uptake values (SUVs) were determined, and analysis of variance was performed, with group (smoker vs non-smoker) and genotype as factors, thereby controlling for genotype. Smokers and non-smokers differed in whole-brain SUVs (P=0.006) owing to smokers having 16.8% lower values than non-smokers. The groups did not differ in injected radiotracer dose or body weight, which were used to calculate SUV. An inverse association was found between whole-brain SUV and reported cigarettes per day (P<0.05), but no significant relationship was found for plasma nicotine. Thus, smokers have less [11C]DAA1106 binding globally than non-smokers, indicating less microglial activation. Study findings are consistent with much prior research demonstrating that smokers have impaired inflammatory functioning compared with non-smokers and that constituents of tobacco smoke other than nicotine affect inflammatory processes.
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18
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Donat CK, Scott G, Gentleman SM, Sastre M. Microglial Activation in Traumatic Brain Injury. Front Aging Neurosci 2017; 9:208. [PMID: 28701948 PMCID: PMC5487478 DOI: 10.3389/fnagi.2017.00208] [Citation(s) in RCA: 271] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/12/2017] [Indexed: 12/15/2022] Open
Abstract
Microglia have a variety of functions in the brain, including synaptic pruning, CNS repair and mediating the immune response against peripheral infection. Microglia rapidly become activated in response to CNS damage. Depending on the nature of the stimulus, microglia can take a number of activation states, which correspond to altered microglia morphology, gene expression and function. It has been reported that early microglia activation following traumatic brain injury (TBI) may contribute to the restoration of homeostasis in the brain. On the other hand, if they remain chronically activated, such cells display a classically activated phenotype, releasing pro-inflammatory molecules, resulting in further tissue damage and contributing potentially to neurodegeneration. However, new evidence suggests that this classification is over-simplistic and the balance of activation states can vary at different points. In this article, we review the role of microglia in TBI, analyzing their distribution, morphology and functional phenotype over time in animal models and in humans. Animal studies have allowed genetic and pharmacological manipulations of microglia activation, in order to define their role. In addition, we describe investigations on the in vivo imaging of microglia using translocator protein (TSPO) PET and autoradiography, showing that microglial activation can occur in regions far remote from sites of focal injuries, in humans and animal models of TBI. Finally, we outline some novel potential therapeutic approaches that prime microglia/macrophages toward the beneficial restorative microglial phenotype after TBI.
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Affiliation(s)
| | | | | | - Magdalena Sastre
- Division of Brain Sciences, Department of Medicine, Imperial College LondonLondon, United Kingdom
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19
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Van Horn JD, Bhattrai A, Irimia A. Multimodal Imaging of Neurometabolic Pathology due to Traumatic Brain Injury. Trends Neurosci 2016; 40:39-59. [PMID: 27939821 DOI: 10.1016/j.tins.2016.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 12/28/2022]
Abstract
The impact of traumatic brain injury (TBI) involves a combination of complex biochemical processes beginning with the initial insult and lasting for days, months and even years post-trauma. These changes range from neuronal integrity losses to neurotransmitter imbalance and metabolite dysregulation, leading to the release of pro- or anti-apoptotic factors which mediate cell survival or death. Such dynamic processes affecting the brain's neurochemistry can be monitored using a variety of neuroimaging techniques, whose combined use can be particularly useful for understanding patient-specific clinical trajectories. Here, we describe how TBI changes the metabolism of essential neurochemical compounds, summarize how neuroimaging approaches facilitate the study of such alterations, and highlight promising ways in which neuroimaging can be used to investigate post-TBI changes in neurometabolism.
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Affiliation(s)
- John Darrell Van Horn
- USC Mark and Mary Stevens Neuroimaging and Informatics Institute, 2025 Zonal Avenue, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA.
| | - Avnish Bhattrai
- USC Mark and Mary Stevens Neuroimaging and Informatics Institute, 2025 Zonal Avenue, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA
| | - Andrei Irimia
- USC Mark and Mary Stevens Neuroimaging and Informatics Institute, 2025 Zonal Avenue, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA
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20
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Early Inflammatory Response following Traumatic Brain Injury in Rabbits Using USPIO- and Gd-Enhanced MRI. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8431987. [PMID: 27868069 PMCID: PMC5102713 DOI: 10.1155/2016/8431987] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/04/2016] [Indexed: 11/28/2022]
Abstract
Purpose. To monitor the inflammatory response (IR) following traumatic brain injury (TBI) before and after the rehabilitation of the blood-brain barrier (BBB) in rabbits using USPIO- and Gd-enhanced MRI. Materials and Methods. Twenty white big-eared rabbits with mild TBI (mTBI) were randomly and equally divided into four groups. Rabbits were sacrificed for the brain specimens immediately after the last MRI-monitoring. Sequences were tse-T1WI, tse-T2WI, Gd-T1WI, and USPIO-T1WI. Dynamical MRI presentations were evaluated and compared with pathological findings for each group. Results. Twenty-four hours after injury, all rabbits displayed high signal foci on T2WI, while only 55% lesions could be found on Gd-T1WI and none on USPIO-T1WI. The lesions were enhanced on Gd-T1WI in 100% subjects after 48 h and the enhancement sizes augmented to the largest after 72 h. At the time point of 72 h after TBI, 90% lesions were enhanced by USPIO. Five days after injury, 19 lesions showed decreased Gd-enhancement and one disappeared; however, USPIO-enhancement became larger than before. Pathological findings showed microglias slightly appeared in dense leukocytes at 48 h, but became the dominant inflammatory cells after five days. Conclusions. Dynamic IR following injury could be monitored by combination of Gd- and USPIO-MRI in mTBI rabbits.
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21
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Vital SA, Gavins FNE. Surgical Approach for Middle Cerebral Artery Occlusion and Reperfusion Induced Stroke in Mice. J Vis Exp 2016. [PMID: 27805602 DOI: 10.3791/54302] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Stroke is a leading cause of death worldwide and continues to be one of the major causes of long-term adult disabilities. About 87% of strokes are ischemic in origin and occur in the territory of the middle cerebral artery (MCA). Currently the only Food and Drug Administration (FDA) approved drug for the treatment of this devastating disease is tissue plasminogen activator (tPA). However, tPA has a small therapeutic window for administration (3 - 6 hr), and is only effective in 4% of the patients who actually receive it. Current research focuses on understanding the pathophysiology of stroke in order to find potential therapeutic targets. Thus, reliable models are crucial, and the MCA occlusion (MCAo) model (also termed the intraluminal filament or suture model) is deemed to be the most clinically relevant surgical model of ischemic stroke, and is fairly non-invasive and easily reproducible. Typically the MCAo model is used with rodents, especially with mice due to all the genetic variations available for this species. Here we describe (and present in the video) how to successfully perform the MCAo model (with reperfusion) in mice to generate reliable and reproducible data.
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Affiliation(s)
- Shantel A Vital
- Department of Molecular & Cellular Physiology, Health Sciences Center Shreveport, Louisiana State University
| | - Felicity N E Gavins
- Department of Molecular & Cellular Physiology, Health Sciences Center Shreveport, Louisiana State University;
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22
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Israel I, Ohsiek A, Al-Momani E, Albert-Weissenberger C, Stetter C, Mencl S, Buck AK, Kleinschnitz C, Samnick S, Sirén AL. Combined [(18)F]DPA-714 micro-positron emission tomography and autoradiography imaging of microglia activation after closed head injury in mice. J Neuroinflammation 2016; 13:140. [PMID: 27266706 PMCID: PMC4897946 DOI: 10.1186/s12974-016-0604-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/30/2016] [Indexed: 11/27/2022] Open
Abstract
Background Traumatic brain injury (TBI) is a major cause of death and disability. Neuroinflammation contributes to acute damage after TBI and modulates long-term evolution of degenerative and regenerative responses to injury. The aim of the present study was to evaluate the relationship of microglia activation to trauma severity, brain energy metabolism, and cellular reactions to injury in a mouse closed head injury model using combined in vivo PET imaging, ex vivo autoradiography, and immunohistochemistry. Methods A weight-drop closed head injury model was used to produce a mixed diffuse and focal TBI or a purely diffuse mild TBI (mTBI) in C57BL6 mice. Lesion severity was determined by evaluating histological damage and functional outcome using a standardized neuroscore (NSS), gliosis, and axonal injury by immunohistochemistry. Repeated intra-individual in vivo μPET imaging with the specific 18-kDa translocator protein (TSPO) radioligand [18F]DPA-714 was performed on day 1, 7, and 16 and [18F]FDG-μPET imaging for energy metabolism on days 2–5 after trauma using freshly synthesized radiotracers. Immediately after [18F]DPA-714-μPET imaging on days 7 and 16, cellular identity of the [18F]DPA-714 uptake was confirmed by exposing freshly cut cryosections to film autoradiography and successive immunostaining with antibodies against the microglia/macrophage marker IBA-1. Results Functional outcome correlated with focal brain lesions, gliosis, and axonal injury. [18F]DPA-714-μPET showed increased radiotracer uptake in focal brain lesions on days 7 and 16 after TBI and correlated with reduced cerebral [18F]FDG uptake on days 2–5, with functional outcome and number of IBA-1 positive cells on day 7. In autoradiography, [18F]DPA-714 uptake co-localized with areas of IBA1-positive staining and correlated strongly with both NSS and the number of IBA1-positive cells, gliosis, and axonal injury. After mTBI, numbers of IBA-1 positive cells with microglial morphology increased in both brain hemispheres; however, uptake of [18F]DPA-714 was not increased in autoradiography or in μPET imaging. Conclusions [18F]DPA-714 uptake in μPET/autoradiography correlates with trauma severity, brain metabolic deficits, and microglia activation after closed head TBI.
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Affiliation(s)
- Ina Israel
- Department of Nuclear Medicine, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Andrea Ohsiek
- Experimental Neurosurgery, Department of Neurosurgery, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Ehab Al-Momani
- Department of Nuclear Medicine, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Christiane Albert-Weissenberger
- Experimental Neurosurgery, Department of Neurosurgery, University Hospital Würzburg, 97080, Würzburg, Germany.,Department of Neurology, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Christian Stetter
- Experimental Neurosurgery, Department of Neurosurgery, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Stine Mencl
- Department of Neurology, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Andreas K Buck
- Department of Nuclear Medicine, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Christoph Kleinschnitz
- Department of Neurology, University Hospital Würzburg, 97080, Würzburg, Germany.,Department of Neurology, University Hospital Essen, 45147, Essen, Germany
| | - Samuel Samnick
- Department of Nuclear Medicine, University Hospital Würzburg, 97080, Würzburg, Germany
| | - Anna-Leena Sirén
- Experimental Neurosurgery, Department of Neurosurgery, University Hospital Würzburg, 97080, Würzburg, Germany.
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Vállez García D, Otte A, Dierckx RAJO, Doorduin J. Three Month Follow-Up of Rat Mild Traumatic Brain Injury: A Combined [ 18F]FDG and [ 11C]PK11195 Positron Emission Study. J Neurotrauma 2016; 33:1855-1865. [PMID: 26756169 DOI: 10.1089/neu.2015.4230] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Mild traumatic brain injury (mTBI) is the most common cause of head trauma. The time course of functional pathology is not well defined, however. The purpose of this study was to evaluate the consequences of mTBI in rats over a period of 3 months by determining the presence of neuroinflammation ([11C]PK11195) and changes in brain metabolism ([18F]FDG) with positron emission tomography (PET) imaging. Male Sprague-Dawley rats were divided in mTBI (n = 8) and sham (n = 8) groups. In vivo PET imaging and behavioral tests (open field, object recognition, and Y-maze) were performed at different time points after induction of the trauma. Differences between groups in PET images were explored using volume-of-interest and voxel-based analysis. mTBI did not result in death, skull fracture, or suppression of reflexes. Weight gain was reduced (p = 0.003) in the mTBI group compared with the sham-treated group. No statistical differences were found in the behavioral tests at any time point. Volume-of-interest analysis showed neuroinflammation limited to the subacute phase (day 12) involving amygdala, globus pallidus, hypothalamus, pons, septum, striatum, and thalamus (p < 0.03, d > 1.2). Alterations in glucose metabolism were detected over the 3 month period, with increased uptake in the medulla (p < 0.04, d ≥ 1.2), and decreased uptake in the globus pallidus, striatum, and thalamus (p < 0.04, d ≤ 1.2). Similar findings were observed in the voxel-based analysis (p < 0.05 at corrected cluster level). As a consequence of the mTBI, and in the absence of apparent behavioral alterations, relative brain glucose metabolism was found altered in several brain regions, which mostly correspond with those presenting neuroinflammation in the subacute stage.
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Affiliation(s)
- David Vállez García
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen , Groningen, The Netherlands
| | - Andreas Otte
- 2 Division of Biomedical Engineering, Department of Electrical Engineering and Information Technology, Offenburg University , Offenburg, Germany
| | - Rudi A J O Dierckx
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen , Groningen, The Netherlands
| | - Janine Doorduin
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen , Groningen, The Netherlands
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Changes in Binding of [(123)I]CLINDE, a High-Affinity Translocator Protein 18 kDa (TSPO) Selective Radioligand in a Rat Model of Traumatic Brain Injury. Neuromolecular Med 2016; 18:158-69. [PMID: 26969181 DOI: 10.1007/s12017-016-8385-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/02/2016] [Indexed: 01/01/2023]
Abstract
After traumatic brain injury (TBI), secondary injuries develop, including neuroinflammatory processes that contribute to long-lasting impairments. These secondary injuries represent potential targets for treatment and diagnostics. The translocator protein 18 kDa (TSPO) is expressed in activated microglia cells and upregulated in response to brain injury and therefore a potential biomarker of the neuroinflammatory processes. Second-generation radioligands of TSPO, such as [(123)I]CLINDE, have a higher signal-to-noise ratio as the prototype ligand PK11195. [(123)I]CLINDE has been employed in human studies using single-photon emission computed tomography to image the neuroinflammatory response after stroke. In this study, we used the same tracer in a rat model of TBI to determine changes in TSPO expression. Adult Sprague-Dawley rats were subjected to moderate controlled cortical impact injury and sacrificed at 6, 24, 72 h and 28 days post surgery. TSPO expression was assessed in brain sections employing [(123)I]CLINDE in vitro autoradiography. From 24 h to 28 days post surgery, injured animals exhibited a marked and time-dependent increase in [(123)I]CLINDE binding in the ipsilateral motor, somatosensory and parietal cortex, as well as in the hippocampus and thalamus. Interestingly, binding was also significantly elevated in the contralateral M1 motor cortex following TBI. Craniotomy without TBI caused a less marked increase in [(123)I]CLINDE binding, restricted to the ipsilateral hemisphere. Radioligand binding was consistent with an increase in TSPO mRNA expression and CD11b immunoreactivity at the contusion site. This study demonstrates the applicability of [(123)I]CLINDE for detailed regional and quantitative assessment of glial activity in experimental models of TBI.
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Gao X, Wang X, Xiong W, Chen J. In vivo reprogramming reactive glia into iPSCs to produce new neurons in the cortex following traumatic brain injury. Sci Rep 2016; 6:22490. [PMID: 26957147 PMCID: PMC4783661 DOI: 10.1038/srep22490] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/12/2016] [Indexed: 01/14/2023] Open
Abstract
Traumatic brain injury (TBI) results in a significant amount of cell death in the brain. Unfortunately, the adult mammalian brain possesses little regenerative potential following injury and little can be done to reverse the initial brain damage caused by trauma. Reprogramming adult cells to generate induced pluripotent stem cell (iPSCs) has opened new therapeutic opportunities to generate neurons in a non-neurogenic regions in the cortex. In this study we showed that retroviral mediated expression of four transcription factors, Oct4, Sox2, Klf4, and c-Myc, cooperatively reprogrammed reactive glial cells into iPSCs in the adult neocortex following TBI. These iPSCs further differentiated into a large number of neural stem cells, which further differentiated into neurons and glia in situ, and filled up the tissue cavity induced by TBI. The induced neurons showed a typical neuronal morphology with axon and dendrites, and exhibited action potential. Our results report an innovative technology to transform reactive glia into a large number of functional neurons in their natural environment of neocortex without embryo involvement and without the need to grow cells outside the body and then graft them back to the brain. Thus this technology offers hope for personalized regenerative cell therapies for repairing damaged brain.
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Affiliation(s)
- Xiang Gao
- Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Department of Neurosurgery, Indiana University, 320 W 15th Street, Indianapolis, IN 46202
| | - Xiaoting Wang
- Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Department of Neurosurgery, Indiana University, 320 W 15th Street, Indianapolis, IN 46202
| | - Wenhui Xiong
- Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Department of Neurosurgery, Indiana University, 320 W 15th Street, Indianapolis, IN 46202
| | - Jinhui Chen
- Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Department of Neurosurgery, Indiana University, 320 W 15th Street, Indianapolis, IN 46202
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Yang Z, Wang KKW. Glial fibrillary acidic protein: from intermediate filament assembly and gliosis to neurobiomarker. Trends Neurosci 2015; 38:364-74. [PMID: 25975510 PMCID: PMC4559283 DOI: 10.1016/j.tins.2015.04.003] [Citation(s) in RCA: 547] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 04/03/2015] [Accepted: 04/07/2015] [Indexed: 12/20/2022]
Abstract
Glial fibrillary acidic protein (GFAP) is an intermediate filament (IF) III protein uniquely found in astrocytes in the central nervous system (CNS), non-myelinating Schwann cells in the peripheral nervous system (PNS), and enteric glial cells. GFAP mRNA expression is regulated by several nuclear-receptor hormones, growth factors, and lipopolysaccharides (LPSs). GFAP is also subject to numerous post-translational modifications (PTMs), while GFAP mutations result in protein deposits known as Rosenthal fibers in Alexander disease. GFAP gene activation and protein induction appear to play a critical role in astroglial cell activation (astrogliosis) following CNS injuries and neurodegeneration. Emerging evidence also suggests that, following traumatic brain and spinal cord injuries and stroke, GFAP and its breakdown products are rapidly released into biofluids, making them strong candidate biomarkers for such neurological disorders.
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Affiliation(s)
- Zhihui Yang
- Program for Neurotrauma, Neuroproteomics, and Biomarkers Research, Departments of Psychiatry and Neuroscience, McKnight Brain Institute, L4-100, University of Florida, 1149 South Newell Drive, Gainesville, FL 32611, USA
| | - Kevin K W Wang
- Program for Neurotrauma, Neuroproteomics, and Biomarkers Research, Departments of Psychiatry and Neuroscience, McKnight Brain Institute, L4-100, University of Florida, 1149 South Newell Drive, Gainesville, FL 32611, USA.
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Kulkarni P, Kenkel W, Finklestein SP, Barchet TM, Ren J, Davenport M, Shenton ME, Kikinis Z, Nedelman M, Ferris CF. Use of Anisotropy, 3D Segmented Atlas, and Computational Analysis to Identify Gray Matter Subcortical Lesions Common to Concussive Injury from Different Sites on the Cortex. PLoS One 2015; 10:e0125748. [PMID: 25955025 PMCID: PMC4425537 DOI: 10.1371/journal.pone.0125748] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 03/26/2015] [Indexed: 01/15/2023] Open
Abstract
Traumatic brain injury (TBI) can occur anywhere along the cortical mantel. While the cortical contusions may be random and disparate in their locations, the clinical outcomes are often similar and difficult to explain. Thus a question that arises is, do concussions at different sites on the cortex affect similar subcortical brain regions? To address this question we used a fluid percussion model to concuss the right caudal or rostral cortices in rats. Five days later, diffusion tensor MRI data were acquired for indices of anisotropy (IA) for use in a novel method of analysis to detect changes in gray matter microarchitecture. IA values from over 20,000 voxels were registered into a 3D segmented, annotated rat atlas covering 150 brain areas. Comparisons between left and right hemispheres revealed a small population of subcortical sites with altered IA values. Rostral and caudal concussions were of striking similarity in the impacted subcortical locations, particularly the central nucleus of the amygdala, laterodorsal thalamus, and hippocampal complex. Subsequent immunohistochemical analysis of these sites showed significant neuroinflammation. This study presents three significant findings that advance our understanding and evaluation of TBI: 1) the introduction of a new method to identify highly localized disturbances in discrete gray matter, subcortical brain nuclei without postmortem histology, 2) the use of this method to demonstrate that separate injuries to the rostral and caudal cortex produce the same subcortical, disturbances, and 3) the central nucleus of the amygdala, critical in the regulation of emotion, is vulnerable to concussion.
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Affiliation(s)
- Praveen Kulkarni
- Northeastern University, Boston, Massachusetts, United States of America
| | - William Kenkel
- Northeastern University, Boston, Massachusetts, United States of America
| | | | - Thomas M. Barchet
- Northeastern University, Boston, Massachusetts, United States of America
| | - JingMei Ren
- Biotrofix, Waltham, Massachusetts, United States of America
| | | | - Martha E. Shenton
- Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Zora Kikinis
- Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Mark Nedelman
- Ekam Imaging, Boston, Massachusetts, United States of America
| | - Craig F. Ferris
- Northeastern University, Boston, Massachusetts, United States of America
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Brody AL, Okita K, Shieh J, Liang L, Hubert R, Mamoun M, Farahi J, Mandelkern MA. Radiation dosimetry and biodistribution of the translocator protein radiotracer [(11)C]DAA1106 determined with PET/CT in healthy human volunteers. Nucl Med Biol 2014; 41:871-5. [PMID: 25156039 PMCID: PMC4192057 DOI: 10.1016/j.nucmedbio.2014.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/11/2014] [Accepted: 07/15/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION When microglia become activated (an integral part of neuroinflammation), cellular morphology changes and expression of translocator protein (TSPO) 18 kDa is increased. Over the past several years, [(11)C]DAA1106 has emerged as a reliable radiotracer for labeling TSPO with high affinity during positron emission tomography (PET) scanning. While [(11)C]DAA1106 PET scanning has been used in several research studies, a radiation dosimetry study of this radiotracer in humans has not yet been published. METHODS Twelve healthy participants underwent full body dynamic [(11)C]DAA1106 PET scanning, with 8 sequential whole body scans (approximately 12 bed positions each), following a single injection. Regions of interest were drawn manually, and time activity curves (TACs) were obtained for 15 organs. OLINDA/EXM 1.1 was used to compute radiation absorbed doses to the target organs, as well as effective dose (ED) and effective dose equivalent (EDE). RESULTS The ED and EDE were 4.06 ± 0.58 μSv/MBq and 5.89 ± 0.83 μSv/MBq, respectively. The highest absorbed doses were to the heart wall, kidney, liver, pancreas, and spleen. TACs revealed that peak dose rates are during the first scan (at 6 min) for all organs other than the urinary bladder wall, which had its peak dose rate during the fourth scan (at 30 min). CONCLUSIONS The recently developed radiotracer [(11)C]DAA1106 has its EDE and target-organ absorbed dose such that, for a single administration, its radiation dosimetry is well within the U.S. FDA guidelines for basic research studies in adults. This dose level implies that the dosimetry for multiple [(11)C]DAA1106 scans within a given year also falls within FDA guidelines, and this favorable property makes this radiotracer suitable for examining microglial activation repeatedly over time, which may in the future be useful for longitudinal tracking of disease progression and monitoring of therapy response in conditions marked by neuroinflammation (e.g., head trauma and multiple sclerosis).
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Affiliation(s)
- Arthur L Brody
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073; Department of Psychiatry, University of California at Los Angeles, 300 UCLA Medical Plaza, Suite 2200, Los Angeles, CA 90095.
| | - Kyoji Okita
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073; UCLA Laboratory of Molecular Imaging, 760 Westwood Plaza C8-538, Los Angeles, CA 90095
| | - Jennifer Shieh
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Lidia Liang
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Robert Hubert
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Michael Mamoun
- Department of Research, VA Greater Los Angeles Healthcare System (VAGLAHS), 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Judah Farahi
- Department of Imaging, VAGLAHS, 11301 Wilshire Blvd., Los Angeles, CA 90073
| | - Mark A Mandelkern
- Department of Imaging, VAGLAHS, 11301 Wilshire Blvd., Los Angeles, CA 90073; Department of Physics, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697
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Steuer E, Schaefer ML, Belluscio L. Using the olfactory system as an in vivo model to study traumatic brain injury and repair. J Neurotrauma 2014; 31:1277-91. [PMID: 24694002 DOI: 10.1089/neu.2013.3296] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Loss of olfactory function is an early indicator of traumatic brain injury (TBI). The regenerative capacity and well-defined neural maps of the mammalian olfactory system enable investigations into the degeneration and recovery of neural circuits after injury. Here, we introduce a unique olfactory-based model of TBI that reproduces many hallmarks associated with human brain trauma. We performed a unilateral penetrating impact to the mouse olfactory bulb and observed a significant loss of olfactory sensory neurons (OSNs) in the olfactory epithelium (OE) ipsilateral to the injury, but not contralateral. By comparison, we detected the injury markers p75(NTR), β-APP, and activated caspase-3 in both the ipsi- and contralateral OE. In the olfactory bulb (OB), we observed a graded cell loss, with ipsilateral showing a greater reduction than contralateral and both significantly less than sham. Similar to OE, injury markers in the OB were primarily detected on the ipsilateral side, but also observed contralaterally. Behavioral experiments measured 4 days after impact also demonstrated loss of olfactory function, yet following a 30-day recovery period, we observed a significant improvement in olfactory function and partial recovery of olfactory circuitry, despite the persistence of TBI markers. Interestingly, by using the M71-IRES-tauLacZ reporter line to track OSN organization, we further determined that inducing neural activity during the recovery period with intense odor conditioning did not enhance the recovery process. Together, these data establish the mouse olfactory system as a new model to study TBI, serving as a platform to understand neural disruption and the potential for circuit restoration.
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Affiliation(s)
- Elizabeth Steuer
- 1 Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health , Bethesda, Maryland
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PET imaging of neuroinflammation in a rat traumatic brain injury model with radiolabeled TSPO ligand DPA-714. Eur J Nucl Med Mol Imaging 2014; 41:1440-9. [PMID: 24615467 DOI: 10.1007/s00259-014-2727-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/05/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE The inflammatory response in injured brain parenchyma after traumatic brain injury (TBI) is crucial in the pathological process. In order to follow microglia activation and neuroinflammation after TBI, we performed PET imaging in a rat model of TBI using (18)F-labeled DPA-714, a ligand of the 18-kDa translocator protein (TSPO). METHODS TBI was induced in male SD rats by a controlled cortical impact. The success of the TBI model was confirmed by MRI. [(18)F]DPA-714 was synthesized using a slightly modified TRACERLab FX-FN module and an automated procedure. In vivo PET imaging was performed at different time points after surgery using an Inveon small-animal PET scanner. The specificity of [(18)F]DPA-714 was confirmed by a displacement study with an unlabeled competitive TSPO ligand, PK11195. Ex vivo autoradiography as well as immunofluorescence staining was carried out to confirm the in vivo PET results. RESULTS Both in vivo T2-weighted MR images and ex vivo TTC staining results revealed successful establishment of the TBI model. Compared with the sham-treated group, [(18)F]DPA-714 uptake was significantly higher in the injured brain area on PET images. Increased lesion-to-normal ratios of [(18)F]DPA-714 were observed in the brain of TBI rats on day 2 after surgery. Ratios peaked around day 6 (2.65 ± 0.36) and then decreased gradually to nearly normal levels on day 28. The displacement study using PK11195 confirmed the specific binding of [(18)F]DPA-714 to TSPO. The results of ex vivo autoradiography were consistent with in vivo PET results. Immunofluorescence staining showed the time course of TSPO expression after TBI and the temporal and the spatial distribution of microglia in the damaged brain area. CONCLUSION TSPO-targeted PET using [(18)F]DPA-714 as the imaging probe can be used to dynamically monitor the inflammatory response after TBI in a noninvasive manner. This method will not only facilitate a better understanding of the inflammatory process after TBI, but also provide a useful in vivo monitoring strategy for antiinflammation therapy of TBI.
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Rodgers KM, Deming YK, Bercum FM, Chumachenko SY, Wieseler JL, Johnson KW, Watkins LR, Barth DS. Reversal of established traumatic brain injury-induced, anxiety-like behavior in rats after delayed, post-injury neuroimmune suppression. J Neurotrauma 2014; 31:487-97. [PMID: 24041015 PMCID: PMC3934516 DOI: 10.1089/neu.2013.3090] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Abstract Traumatic brain injury (TBI) increases the risk of neuropsychiatric disorders, particularly anxiety disorders. Yet, there are presently no therapeutic interventions to prevent the development of post-traumatic anxiety or effective treatments once it has developed. This is because, in large part, of a lack of understanding of the underlying pathophysiology. Recent research suggests that chronic neuroinflammatory responses to injury may play a role in the development of post-traumatic anxiety in rodent models. Acute peri-injury administration of immunosuppressive compounds, such as Ibudilast (MN166), have been shown to prevent reactive gliosis associated with immune responses to injury and also prevent lateral fluid percussion injury (LFPI)-induced anxiety-like behavior in rats. There is evidence in both human and rodent studies that post-traumatic anxiety, once developed, is a chronic, persistent, and drug-refractory condition. In the present study, we sought to determine whether neuroinflammation is associated with the long-term maintenance of post-traumatic anxiety. We examined the efficacy of an anti-inflammatory treatment in decreasing anxiety-like behavior and reactive gliosis when introduced at 1 month after injury. Delayed treatment substantially reduced established LFPI-induced freezing behavior and reactive gliosis in brain regions associated with anxiety and continued neuroprotective effects were evidenced 6 months post-treatment. These results support the conclusion that neuroinflammation may be involved in the development and maintenance of anxiety-like behaviors after TBI.
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Affiliation(s)
- Krista M. Rodgers
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | - Yuetiva K. Deming
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | - Florencia M. Bercum
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | - Serhiy Y. Chumachenko
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | - Julie L. Wieseler
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | | | - Linda R. Watkins
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| | - Daniel S. Barth
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
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Wu C, Yue X, Lang L, Kiesewetter DO, Li F, Zhu Z, Niu G, Chen X. Longitudinal PET imaging of muscular inflammation using 18F-DPA-714 and 18F-Alfatide II and differentiation with tumors. Theranostics 2014; 4:546-55. [PMID: 24672585 PMCID: PMC3966057 DOI: 10.7150/thno.8159] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/25/2014] [Indexed: 12/14/2022] Open
Abstract
AIM (18)F-DPA-714 is a PET tracer that recognizes macrophage translocator protein (TSPO), and (18)F-Alfatide II ((18)F-AlF-NOTA-E[PEG4-c(RGDfk)]2) is specific for integrin αvβ3. This study aims to apply these two tracers for longitudinal PET imaging of muscular inflammation, and evaluate the value of (18)F-DPA-714 in differentiating inflammation from tumor. METHODS RAW264.7 mouse macrophage cells were used for cell uptake analysis of (18)F-DPA-714. A mouse hind limb muscular inflammation model was established by intramuscular injection of turpentine oil. For the inflammation model, PET imaging was performed at different days using (18)F-DPA-714 and (18)F-Alfatide II. The specificity of the imaging probes was tested by co- or pre-injection of PK11195 or unlabeled RGD (Arg-Gly-Asp) peptide. PET imaging using (18)F-DPA-714 was performed in A549, HT29, U87MG, INS-1, and 4T1 xenograft models. Immunofluorescence staining was performed to evaluate infiltrated macrophages and angiogenesis in inflammation and/or tumors. RESULTS Uptake of (18)F-DPA-714 in RAW264.7 cells was 45.5% at 1 h after incubation, and could be blocked by PK11195. PET imaging showed increased (18)F-DPA-714 and (18)F-Alfatide II uptake at inflammatory muscles. Peak uptake of (18)F-DPA-714 was seen on day 6 (4.02 ± 0.64 %ID/g), and peak uptake of (18)F-Alfatide II was shown on day 12 (1.87 ± 0.35 %ID/g) at 1 h p.i.. Tracer uptakes could be inhibited by PK11195 for (18)F-DPA-714 or cold RGD for (18)F-Alfatide II. Moreover, macrophage depletion with liposomal clodronate also reduced the local accumulation of both tracers. A549, HT29, U87MG, INS-1, and 4T1 tumor uptakes of (18)F-DPA-714 (0.46 ± 0.28, 0.91 ± 0.08, 1.69 ± 0.67, 1.13 ± 0.33, 1.22 ± 0.55 %ID/g at 1 h p.i., respectively) were significantly lower than inflammation uptake (All P < 0.05). CONCLUSION PET imaging using (18)F-DPA-714 as a TSPO targeting tracer could evaluate the dynamics of macrophage activation and infiltration in different stages of inflammatory diseases. The concomitant longitudinal PET imaging with both (18)F-DPA-714 and (18)F-Alfatide II matched the causal relationship between macrophage infiltration and angiogenesis. Moreover, we found (18)F-DPA-714 uptake in several types of tumors is significantly lower than that in inflammatory muscles, suggesting (18)F-DPA-714 PET has the potential for better differentiation of tumor and non-tumor inflammation.
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Selwyn R, Hockenbury N, Jaiswal S, Mathur S, Armstrong RC, Byrnes KR. Mild traumatic brain injury results in depressed cerebral glucose uptake: An (18)FDG PET study. J Neurotrauma 2013; 30:1943-53. [PMID: 23829400 DOI: 10.1089/neu.2013.2928] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Moderate to severe traumatic brain injury (TBI) in humans and rats induces measurable metabolic changes, including a sustained depression in cerebral glucose uptake. However, the effect of a mild TBI on brain glucose uptake is unclear, particularly in rodent models. This study aimed to determine the glucose uptake pattern in the brain after a mild lateral fluid percussion (LFP) TBI. Briefly, adult male rats were subjected to a mild LFP and positron emission tomography (PET) imaging with (18)F-fluorodeoxyglucose ((18)FDG), which was performed prior to injury and at 3 and 24 h and 5, 9, and 16 days post-injury. Locomotor function was assessed prior to injury and at 1, 3, 7, 14, and 21 days after injury using modified beam walk tasks to confirm injury severity. Histology was performed at either 10 or 21 days post-injury. Analysis of function revealed a transient impairment in locomotor ability, which corresponds to a mild TBI. Using reference region normalization, PET imaging revealed that mild LFP-induced TBI depresses glucose uptake in both the ipsilateral and contralateral hemispheres in comparison with sham-injured and naïve controls from 3 h to 5 days post-injury. Further, areas of depressed glucose uptake were associated with regions of glial activation and axonal damage, but no measurable change in neuronal loss or gross tissue damage was observed. In conclusion, we show that mild TBI, which is characterized by transient impairments in function, axonal damage, and glial activation, results in an observable depression in overall brain glucose uptake using (18)FDG-PET.
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Affiliation(s)
- Reed Selwyn
- 1 Department of Radiology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
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Wu HM, Huang SC, Vespa P, Hovda DA, Bergsneider M. Redefining the pericontusional penumbra following traumatic brain injury: evidence of deteriorating metabolic derangements based on positron emission tomography. J Neurotrauma 2013; 30:352-60. [PMID: 23461651 DOI: 10.1089/neu.2012.2610] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract The pathophysiological changes in the pericontusional region after traumatic brain injury (TBI) have classically been considered to be ischemic. Using [F-18]fluorodeoxyglucose (FDG) and triple-oxygen PET studies, we examined the pericontusional "penumbra" to assess for increased oxygen extraction fraction (OEF), anaerobic metabolism, and tissue viability. Acute (≤4 days) CT, MRI, and PET studies were performed in eight patients with TBI who had contusions. Four regions-of-interest (ROI) containing the contusion core, pericontusional hypodense gray matter (GM), pericontusional normal-appearing GM, and remote normal-appearing GM, were defined using a semi-automatic method. The correlations of cerebral blood flow (CBF) with OEF, cerebral metabolic rate of oxygen (CMRO2), and cerebral metabolic rate of glucose (CMRglc) were examined. The oxygen-glucose ratio (OGR) in each brain region was evaluated for anaerobic metabolism. The results show that pericontusional tissue had progressively diminishing OEF, CBF, CMRO2, or CMRglc approaching the contusion core. In general, there was a preserved ratio of CBF to CMRO2 in pericontusional hypodense GM. The OGR of the pericontusional hypodense GM was low (<4.0) and was inversely correlated (r=-0.68) with time after injury. A large proportion (%area: 22-76%) of pericontusional hypodense GM tissue had CMRO2 values less than 35 μmol/100 g/min, with this percentage increased with time after injury.
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Affiliation(s)
- Hsiao-Ming Wu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-7039, USA
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Wu C, Li F, Niu G, Chen X. PET imaging of inflammation biomarkers. Theranostics 2013; 3:448-66. [PMID: 23843893 PMCID: PMC3706689 DOI: 10.7150/thno.6592] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 05/24/2013] [Indexed: 01/04/2023] Open
Abstract
Inflammation plays a significant role in many disease processes. Development in molecular imaging in recent years provides new insight into the diagnosis and treatment evaluation of various inflammatory diseases and diseases involving inflammatory process. Positron emission tomography using (18)F-FDG has been successfully applied in clinical oncology and neurology and in the inflammation realm. In addition to glucose metabolism, a variety of targets for inflammation imaging are being discovered and utilized, some of which are considered superior to FDG for imaging inflammation. This review summarizes the potential inflammation imaging targets and corresponding PET tracers, and the applications of PET in major inflammatory diseases and tumor associated inflammation. Also, the current attempt in differentiating inflammation from tumor using PET is also discussed.
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Li J, Gu L, Feng DF, Ding F, Zhu G, Rong J. Exploring temporospatial changes in glucose metabolic disorder, learning, and memory dysfunction in a rat model of diffuse axonal injury. J Neurotrauma 2013; 29:2635-46. [PMID: 22880625 DOI: 10.1089/neu.2012.2411] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Diffuse axonal injury (DAI) is the predominant effect of severe traumatic brain injury and contributes significantly to cognitive deficits. The mechanisms underlying these cognitive deficits are often associated with complex metabolic alterations. However, the relationships between temporospatial alterations in cerebral glucose metabolism and the pathophysiology of DAI-related learning and memory dysfunction are not yet completely understood. We used a small animal positron emission tomography (PET) scanner with 2-[F-18]-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) as a molecular probe to evaluate temporospatial glucose metabolism in vulnerable areas of rats with DAI. The Morris water maze (MWM) was used to evaluate the development and progression of learning and memory dysfunction. Compared to the sham-treated group, PET-MRI fusion images showed that glucose metabolism was reduced in animals with DAI. In addition, the standardized uptake value (SUV) of ¹⁸F-FDG was significantly decreased in the sensorimotor cortex, hippocampus, corpus callosum, caudate putamen, brain stem, and cerebellum at days 1, 3, and 7 after injury. SUV returned to baseline levels by 30 days after injury. The escape latency of the injured group was significantly increased, and the percentages of distance travelled and time spent in the target quadrant were significantly decreased 1 month after injury. These effects persisted for 3 months. SUVs in the hippocampus at the acute stage were significantly correlated with MWM performance during the recovery stage of DAI. These results demonstrate that microstructural injury-induced hypometabolism in the hippocampus at the acute stage are all significantly correlated with learning and memory dysfunctions during the recovery stage of DAI.
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Affiliation(s)
- Jia Li
- Department of Neurosurgery, No. 3 People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
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Hernandez-Ontiveros DG, Tajiri N, Acosta S, Giunta B, Tan J, Borlongan CV. Microglia activation as a biomarker for traumatic brain injury. Front Neurol 2013; 4:30. [PMID: 23531681 PMCID: PMC3607801 DOI: 10.3389/fneur.2013.00030] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 03/10/2013] [Indexed: 12/24/2022] Open
Abstract
Traumatic brain injury (TBI) has become the signature wound of wars in Afghanistan and Iraq. Injury may result from a mechanical force, a rapid acceleration-deceleration movement, or a blast wave. A cascade of secondary cell death events ensues after the initial injury. In particular, multiple inflammatory responses accompany TBI. A series of inflammatory cytokines and chemokines spreads to normal brain areas juxtaposed to the core impacted tissue. Among the repertoire of immune cells involved, microglia is a key player in propagating inflammation to tissues neighboring the core site of injury. Neuroprotective drug trials in TBI have failed, likely due to their sole focus on abrogating neuronal cell death and ignoring the microglia response despite these inflammatory cells’ detrimental effects on the brain. Another relevant point to consider is the veracity of results of animal experiments due to deficiencies in experimental design, such as incomplete or inadequate method description, data misinterpretation, and reporting may introduce bias and give false-positive results. Thus, scientific publications should follow strict guidelines that include randomization, blinding, sample-size estimation, and accurate handling of all data (Landis et al., 2012). A prolonged state of inflammation after brain injury may linger for years and predispose patients to develop other neurological disorders, such as Alzheimer’s disease. TBI patients display progressive and long-lasting impairments in their physical, cognitive, behavioral, and social performance. Here, we discuss inflammatory mechanisms that accompany TBI in an effort to increase our understanding of the dynamic pathological condition as the disease evolves over time and begin to translate these findings for defining new and existing inflammation-based biomarkers and treatments for TBI.
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Affiliation(s)
- Diana G Hernandez-Ontiveros
- Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, Morsani College of Medicine, University of South Florida Tampa, FL, USA
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Bingham D, John CM, Levin J, Panter SS, Jarvis GA. Post-injury conditioning with lipopolysaccharide or lipooligosaccharide reduces inflammation in the brain. J Neuroimmunol 2013; 256:28-37. [PMID: 23333234 DOI: 10.1016/j.jneuroim.2012.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/19/2012] [Accepted: 12/20/2012] [Indexed: 01/13/2023]
Abstract
BACKGROUND Traumatic brain injury (TBI) is a leading cause of mortality and disability in the Western world. The first stage of TBI results from the mechanical damage from an impact or blast. A second stage occurs as an inflammatory response to the primary injury and presents an opportunity for clinical intervention. In this study, we investigated the effect of pre- and post-injury treatment with lipopolysaccharide (LPS) from Escherichia coli and lipooligosaccharide (LOS) from Neisseria meningitidis on levels of cerebral inflammatory cells, circulating blood cells, and pro- and anti-inflammatory cytokine levels in a rat model of neuroinflammation induced by intrastriatal injection of IL-1β to mimic the second stage of TBI. METHODS LPS or LOS was administered intravenously (IV) or intranasally (IN) 2h pre- or post-injection of IL-1β. The rats were euthanized 12h following IL-1β injection. Brain sections were immunostained with antibody to ED-1, a microglia cell marker. Cells in whole blood were assessed with a VetScan HM2 analyzer, and cytokine levels in sera were analyzed with a Bio-Plex system. RESULTS Pre- and post-injury IV administration of LPS or LOS significantly reduced microglia in the brain, and IN pre-treatment with LPS or LOS showed a statistical trend towards reducing microglia. Pre- and post-treatment IV with LOS increased circulating levels of IL-2 and IL-4, whereas IN post-treatment with LPS reduced levels of the inflammatory cytokines, TNF-α and IFN-γ. CONCLUSIONS The findings strongly support continued investigation of post-conditioning with LPS or LOS as potential neuroprotective treatments for neuroinflammation from TBI.
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Affiliation(s)
- Deborah Bingham
- Center for Immunochemistry, 4150 Clement Street, Veterans Affairs Medical Center, San Francisco, CA 94121, USA
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Lin Y, Wen L. Inflammatory response following diffuse axonal injury. Int J Med Sci 2013; 10:515-21. [PMID: 23532682 PMCID: PMC3607236 DOI: 10.7150/ijms.5423] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 03/06/2013] [Indexed: 12/12/2022] Open
Abstract
DAI is a leading cause of the patient's death or lasting vegetable state following severe TBI, and up to now the detailed mechanism of axonal injury after head trauma is still unclear. Inflammatory responses have been proved to be an important mechanism of neural injury after TBI. However, most of these studies are concerned with focal cerebral injury following head trauma. In contrast to focal injury, studies on the inflammatory reaction following DAI are only beginning. And in this article, we aimed to review such studies. From the studies reviewed, immune response cells would become reactive around the sites of axonal injury after DAI. Besides, the concentrations of several important inflammatory factors, such as IL-1 family, IL-6 and TNF-ɑ, increased after DAI as well, which implies the participation of inflammatory responses. It can be concluded that inflammatory responses probably participate in the neural injury in DAI, but at present the study of inflammatory responses following DAI is still limited and the clear effects of inflammatory response on axonal injury remain to be more explored.
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Affiliation(s)
- Yu Lin
- School of Medicine, Zhejiang University City College, China
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Rodgers KM, Bercum FM, McCallum DL, Rudy JW, Frey LC, Johnson KW, Watkins LR, Barth DS. Acute neuroimmune modulation attenuates the development of anxiety-like freezing behavior in an animal model of traumatic brain injury. J Neurotrauma 2012; 29:1886-97. [PMID: 22435644 PMCID: PMC3390983 DOI: 10.1089/neu.2011.2273] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Chronic anxiety is a common and debilitating result of traumatic brain injury (TBI) in humans. While little is known about the neural mechanisms of this disorder, inflammation resulting from activation of the brain's immune response to insult has been implicated in both human post-traumatic anxiety and in recently developed animal models. In this study, we used a lateral fluid percussion injury (LFPI) model of TBI in the rat and examined freezing behavior as a measure of post-traumatic anxiety. We found that LFPI produced anxiety-like freezing behavior accompanied by increased reactive gliosis (reflecting neuroimmune inflammatory responses) in key brain structures associated with anxiety: the amygdala, insula, and hippocampus. Acute peri-injury administration of ibudilast (MN166), a glial cell activation inhibitor, suppressed both reactive gliosis and freezing behavior, and continued neuroprotective effects were apparent several months post-injury. These results support the conclusion that inflammation produced by neuroimmune responses to TBI play a role in post-traumatic anxiety, and that acute suppression of injury-induced glial cell activation may have promise for the prevention of post-traumatic anxiety in humans.
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Affiliation(s)
- Krista M. Rodgers
- Department of Psychology and Neuroscience, University of Colorado–Boulder, Boulder, Colorado
| | - Florencia M. Bercum
- Department of Psychology and Neuroscience, University of Colorado–Boulder, Boulder, Colorado
| | - Danielle L. McCallum
- Department of Psychology and Neuroscience, University of Colorado–Boulder, Boulder, Colorado
| | - Jerry W. Rudy
- Department of Psychology and Neuroscience, University of Colorado–Boulder, Boulder, Colorado
| | - Lauren C. Frey
- Department of Neurology, University of Colorado–Denver, and Colorado Injury Control Research Center, Denver, Colorado
| | | | - Linda R. Watkins
- Department of Psychology and Neuroscience, University of Colorado–Boulder, Boulder, Colorado
| | - Daniel S. Barth
- Department of Psychology and Neuroscience, University of Colorado–Boulder, Boulder, Colorado
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Venneti S, Lopresti BJ, Wiley CA. Molecular imaging of microglia/macrophages in the brain. Glia 2012; 61:10-23. [PMID: 22615180 DOI: 10.1002/glia.22357] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/30/2012] [Indexed: 01/08/2023]
Abstract
Neuroinflammation perpetuates neuronal damage in many neurological disorders. Activation of resident microglia and infiltration of monocytes/macrophages contributes to neuronal injury and synaptic damage. Noninvasive imaging of these cells in vivo provides a means to monitor progression of disease as well as assess efficacies of potential therapeutics. This review provides an overview of positron emission tomography (PET) and magnetic resonance (MR) imaging of microglia/macrophages in the brain. We describe the rationale behind PET imaging of microglia/macrophages with ligands that bind to translocator protein-18 kDa (TSPO). We discuss the prototype TSPO radioligand [(11)C]PK11195, its limitations, and the development of newer TSPO ligands as PET imaging agents. PET imaging agents for targets other than TSPO are emerging, and we outline the potential of these agents for imaging brain microglia/macrophage activity in vivo. Finally, we briefly summarize advances in MR imaging of microglia/macrophages using iron oxide nanoparticles and ultra-small super paramagnetic particles that are phagocytosed. Despite many technical advances, more sensitive agents are required to be useful indicators of neuroinflammation in brain.
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Affiliation(s)
- Sriram Venneti
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
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Virdee K, Cumming P, Caprioli D, Jupp B, Rominger A, Aigbirhio FI, Fryer TD, Riss PJ, Dalley JW. Applications of positron emission tomography in animal models of neurological and neuropsychiatric disorders. Neurosci Biobehav Rev 2012; 36:1188-216. [PMID: 22342372 DOI: 10.1016/j.neubiorev.2012.01.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 01/26/2012] [Accepted: 01/31/2012] [Indexed: 01/08/2023]
Abstract
Positron emission tomography (PET) provides dynamic images of the biodistribution of radioactive tracers in the brain. Through application of the principles of compartmental analysis, tracer uptake can be quantified in terms of specific physiological processes such as cerebral blood flow, cerebral metabolic rate, and the availability of receptors in brain. Whereas early PET studies in animal models of brain diseases were hampered by the limited spatial resolution of PET instruments, dedicated small-animal instruments now provide molecular images of rodent brain with resolution approaching 1mm, the theoretic limit of the method. Major applications of PET for brain research have consisted of studies of animal models of neurological disorders, notably Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease (HD), stroke, epilepsy and traumatic brain injury; these studies have particularly benefited from selective neurochemical lesion models (PD), and also transgenic rodent models (AD, HD). Due to their complex and uncertain pathophysiologies, corresponding models of neuropsychiatric disorders have proven more difficult to establish. Historically, there has been an emphasis on PET studies of dopamine transmission, as assessed with a range of tracers targeting dopamine synthesis, plasma membrane transporters, and receptor binding sites. However, notable recent breakthroughs in molecular imaging include the development of greatly improved tracers for subtypes of serotonin, cannabinoid, and metabotropic glutamate receptors, as well as noradrenaline transporters, amyloid-β and neuroinflammatory changes. This article reviews the considerable recent progress in preclinical PET and discusses applications relevant to a number of neurological and neuropsychiatric disorders in humans.
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Affiliation(s)
- Kanwar Virdee
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
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Higuchi M, Maeda J, Ji B, Tokunaga M, Zhang MR, Maruyama M, Ono M, Fukumura T, Suhara T. PET applications in animal models of neurodegenerative and neuroinflammatory disorders. Curr Top Behav Neurosci 2012; 11:45-64. [PMID: 22016108 DOI: 10.1007/7854_2011_167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Studies on hereditary neurological disorders such as familial Alzheimer's disease (AD) have revealed abnormalities of pathogenic proteins causative of neurodegeneration, while molecular initiators of sporadic neuropsychiatric conditions remain unidentified. Such disorders are characterized by collections of molecular abnormalities that may be critically involved in synaptic dysfunctions and other deteriorations in neurons. Diverse classes of radiochemicals designed for positron emission tomographic (PET) imaging facilitate delineation of mechanistic links among key molecules in these processes by tracking their spatiotemporal correlations. This assay technique is of particular utility when applied to rodent and nonhuman primate models given their suitability for invasive genetic and pharmacological interventions. In addition, the detection of neurochemical and neuropathological changes by PET can be examined in laboratory animals when combined with invasive antemortem and postmortem investigations such as in vivo microdialysis, electrophysiological and histopathological techniques. This review primarily covers the use of small animal models of brain disorders using PET to elucidate etiological molecular cascades to facilitate in turn the search for diagnostic and therapeutic agents applicable to AD and related disorders in humans.
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Affiliation(s)
- Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan,
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Brain hypermetabolism in amyotrophic lateral sclerosis: a FDG PET study in ALS of spinal and bulbar onset. Eur J Nucl Med Mol Imaging 2011; 39:251-9. [DOI: 10.1007/s00259-011-1979-6] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 10/14/2011] [Indexed: 11/26/2022]
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Yu F, Wang Z, Tchantchou F, Chiu CT, Zhang Y, Chuang DM. Lithium ameliorates neurodegeneration, suppresses neuroinflammation, and improves behavioral performance in a mouse model of traumatic brain injury. J Neurotrauma 2011; 29:362-74. [PMID: 21895523 DOI: 10.1089/neu.2011.1942] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Although traumatic brain injury (TBI) is recognized as one of the leading causes of death from trauma to the central nervous system (CNS), no known treatment effectively mitigates its effects. Lithium, a primary drug for the treatment of bipolar disorder, has been known to have neuroprotective effects in various neurodegenerative conditions such as stroke. Until this study, however, it has not been investigated as a post-insult treatment for TBI. To evaluate whether lithium could have beneficial effects following TBI, lithium at a dose of 1.5 mEq/kg was administered after injury. Assessed at 3 days and 3 weeks post-injury using hematoxylin and eosin staining, lithium treatment was found to reduce lesion volume. Lithium at doses of 2.0 and 3.0 mEq/kg also significantly reduced lesion volume at 3 days after injury, and the therapeutic window was at least 3 h post-injury. TBI-induced neuronal death, microglial activation, and cyclooxygenase-2 induction were all attenuated by lithium at 3 days after injury. In addition, lithium treatment reduced TBI-induced matrix metalloproteinase-9 expression and preserved the integrity of the blood-brain barrier. As for behavioral outcomes, lithium treatment reduced anxiety-like behavior in an open-field test, and improved short- and long-term motor coordination in rotarod and beam-walk tests. Lithium robustly increased serine phosphorylation of glycogen synthase kinase-3β (GSK-3β), suggesting that the underlying mechanisms responsible for lithium's protective effects are triggered by increasing phosphorylation of this kinase and thereby inhibiting its activity. Our results support the notion that lithium has heretofore unrecognized capacity to mitigate the neurodegenerative effects and improve functional outcomes in TBI.
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Affiliation(s)
- Fengshan Yu
- Section on Molecular Neurobiology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
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Folkersma H, Foster Dingley JC, van Berckel BNM, Rozemuller A, Boellaard R, Huisman MC, Lammertsma AA, Vandertop WP, Molthoff CFM. Increased cerebral (R)-[(11)C]PK11195 uptake and glutamate release in a rat model of traumatic brain injury: a longitudinal pilot study. J Neuroinflammation 2011; 8:67. [PMID: 21672189 PMCID: PMC3132713 DOI: 10.1186/1742-2094-8-67] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 06/14/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aim of the present study was to investigate microglia activation over time following traumatic brain injury (TBI) and to relate these findings to glutamate release. PROCEDURES Sequential dynamic (R)-[(11)C]PK11195 PET scans were performed in rats 24 hours before (baseline), and one and ten days after TBI using controlled cortical impact, or a sham procedure. Extracellular fluid (ECF) glutamate concentrations were measured using cerebral microdialysis. Brains were processed for histopathology and (immuno)-histochemistry. RESULTS Ten days after TBI, (R)-[(11)C]PK11195 binding was significantly increased in TBI rats compared with both baseline values and sham controls (p < 0.05). ECF glutamate values were increased immediately after TBI (27.6 ± 14.0 μmol·L(-1)) as compared with the sham procedure (6.4 ± 3.6 μmol·L(-1)). Significant differences were found between TBI and sham for ED-1, OX-6, GFAP, Perl's, and Fluoro-Jade B. CONCLUSIONS Increased cerebral uptake of (R)-[(11)C]PK11195 ten days after TBI points to prolonged and ongoing activation of microglia. This activation followed a significant acute posttraumatic increase in ECF glutamate levels.
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Affiliation(s)
- Hedy Folkersma
- Neurosurgical Center Amsterdam, VU University Medical Center, De Boelelaan 1117, NL-1081 HV Amsterdam, The Netherlands.
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Pitkänen A, Bolkvadze T, Immonen R. Anti-epileptogenesis in rodent post-traumatic epilepsy models. Neurosci Lett 2011; 497:163-71. [PMID: 21402123 DOI: 10.1016/j.neulet.2011.02.033] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 01/25/2011] [Accepted: 02/15/2011] [Indexed: 10/18/2022]
Abstract
Post-traumatic epilepsy (PTE) accounts for 10-20% of symptomatic epilepsies. The urgency to understand the process of post-traumatic epileptogenesis and search for antiepileptogenic treatments is emphasized by a recent increase in traumatic brain injury (TBI) related to military combat or accidents in the aging population. Recent developments in modeling of PTE in rodents have provided tools for identification of novel drug targets for antiepileptogenesis and biomarkers for predicting the risk of epileptogenesis and treatment efficacy after TBI. Here we review the available data on endophenotypes of humans and rodents with TBI associated with epilepsy. Also, current understanding of the mechanisms and biomarkers for PTE as well as factors associated with preclinical study designs are discussed. Finally, we summarize the attempts to prevent PTE in experimental models.
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Affiliation(s)
- Asla Pitkänen
- Department of Neurobiology, Epilepsy Research Laboratory, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland.
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