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Yates JR. Aberrant glutamatergic systems underlying impulsive behaviors: Insights from clinical and preclinical research. Prog Neuropsychopharmacol Biol Psychiatry 2024; 135:111107. [PMID: 39098647 PMCID: PMC11409449 DOI: 10.1016/j.pnpbp.2024.111107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 07/07/2024] [Accepted: 07/24/2024] [Indexed: 08/06/2024]
Abstract
Impulsivity is a broad construct that often refers to one of several distinct behaviors and can be measured with self-report questionnaires and behavioral paradigms. Several psychiatric conditions are characterized by one or more forms of impulsive behavior, most notably the impulsive/hyperactive subtype of attention-deficit/hyperactivity disorder (ADHD), mood disorders, and substance use disorders. Monoaminergic neurotransmitters are known to mediate impulsive behaviors and are implicated in various psychiatric conditions. However, growing evidence suggests that glutamate, the major excitatory neurotransmitter of the mammalian brain, regulates important functions that become dysregulated in conditions like ADHD. The purpose of the current review is to discuss clinical and preclinical evidence linking glutamate to separate aspects of impulsivity, specifically motor impulsivity, impulsive choice, and affective impulsivity. Hyperactive glutamatergic activity in the corticostriatal and the cerebro-cerebellar pathways are major determinants of motor impulsivity. Conversely, hypoactive glutamatergic activity in frontal cortical areas and hippocampus and hyperactive glutamatergic activity in anterior cingulate cortex and nucleus accumbens mediate impulsive choice. Affective impulsivity is controlled by similar glutamatergic dysfunction observed for motor impulsivity, except a hyperactive limbic system is also involved. Loss of glutamate homeostasis in prefrontal and nucleus accumbens may contribute to motor impulsivity/affective impulsivity and impulsive choice, respectively. These results are important as they can lead to novel treatments for those with a condition characterized by increased impulsivity that are resistant to conventional treatments.
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Affiliation(s)
- Justin R Yates
- Department of Psychological Science, Northern Kentucky University, 1 Nunn Drive, Highland Heights, KY 41099, USA.
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Onder C, Onder C, Akesen S, Yumusak E, Akesen B. Riluzole is Effective on Spinal Decompression for Treating Acute Spinal Injury When Compared With Methylprednisolone and the Combination of Two Drugs: In Vivo Rat Model. Global Spine J 2024; 14:1899-1908. [PMID: 36812057 PMCID: PMC11418726 DOI: 10.1177/21925682231159068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
STUDY DESIGN Randomized controlled animal experiment. OBJECTIVES To determine and compare the efficacy of riluzole, MPS and the combination of two drugs in a rat model with acute spinal trauma, electrophysiologically and histopathologically. METHODS 59 rats were divided into 4 groups as control, riluzole (6 mg/kg, every 12 hours for 7 days), MPS (30 mg/kg, 2nd and 4th hours after injury) and riluzole + MPS. Spinal trauma was created and the subjects were followed for 7 days. Electrophysiological recordings were made via neuromonitoring. The subjects were sacrificed and histopathological examination was made. RESULTS For the amplitude values, mean alteration in the period from the spinal cord injury to the end of the 7th day is 15.89 ± 20.00%, 210.93 ± 199.44%, 24.75% ± 10.13% increase and 18.91 ± 30.01% decrease for the control, riluzole, riluzole + MPS and MPS groups, respectively. Although the riluzole treatment group produced the greatest increase in amplitude, it was observed that no treatment provided a significant improvement compared to the control group, in terms of latency and amplitude. It was observed that there was significantly less cavitation area in the riluzole treatment group compared to the control group (P = .020). (P < .05). CONCLUSIONS Electrophysiologically, no treatment was found to provide significant improvement. Histopathologically, it was observed that riluzole provided significant neural tissue protection.
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Affiliation(s)
- Cem Onder
- Faculty of Medicine, Department of Orthopaedics and Traumatology, Uludağ University, Bursa, Turkey
| | - Cigdem Onder
- Department of Physical Therapy and Rehabilitation, Sehitkamil Hospital, Gaziantep, Turkey
| | - Selcan Akesen
- Faculty of Medicine, Department of Anesthesiology and Reanimation, Uludağ University, Bursa, Turkey
| | - Ezgi Yumusak
- Faculty of Veterinary Medicine, Department of Pathology, Uludağ University, Bursa, Turkey
| | - Burak Akesen
- Faculty of Medicine, Department of Orthopaedics and Traumatology, Uludağ University, Bursa, Turkey
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Hazell AS. Stem Cell Therapy and Thiamine Deficiency-Induced Brain Damage. Neurochem Res 2024; 49:1450-1467. [PMID: 38720090 DOI: 10.1007/s11064-024-04137-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 01/18/2024] [Accepted: 03/15/2024] [Indexed: 05/21/2024]
Abstract
Wernicke's encephalopathy (WE) is a major central nervous system disorder resulting from thiamine deficiency (TD) in which a number of brain regions can develop serious damage including the thalamus and inferior colliculus. Despite decades of research into the pathophysiology of TD and potential therapeutic interventions, little progress has been made regarding effective treatment following the development of brain lesions and its associated cognitive issues. Recent developments in our understanding of stem cells suggest they are capable of repairing damage and improving function in different maladys. This article puts forward the case for the potential use of stem cell treatment as a therapeutic strategy in WE by first examining the effects of TD on brain functional integrity and its consequences. The second half of the paper will address the future benefits of treating TD with these cells by focusing on their nature and their potential to effectively treat neurodegenerative diseases that share some overlapping pathophysiological features with TD. At the same time, some of the obstacles these cells will have to overcome in order to become a viable therapeutic strategy for treating this potentially life-threatening illness in humans will be highlighted.
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Affiliation(s)
- Alan S Hazell
- Department of Medicine, University of Montreal, 2335 Bennett Avenue, Montreal, QC, H1V 2T6, Canada.
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Liu S, Tian H, Niu Y, Yu C, Xie L, Jin Z, Niu W, Ren J, Fu L, Yao Z. Combined cell grafting and VPA administration facilitates neural repair through axonal regeneration and synaptogenesis in traumatic brain injury. Acta Biochim Biophys Sin (Shanghai) 2022; 54:1289-1300. [PMID: 36148950 PMCID: PMC9828309 DOI: 10.3724/abbs.2022123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Neuronal regeneration and functional recovery are severely compromised following traumatic brain injury (TBI). Treatment options, including cell transplantation and drug therapy, have been shown to benefit TBI, although the underlying mechanisms remain elusive. In this study, neural stem cells (NSCs) are transplanted into TBI-challenged mice, together with olfactory ensheathing cells (OECs) or followed by valproic acid (VPA) treatment. Both OEC grafting and VPA treatment facilitate the differentiation of NSCs into neurons (including endogenous and exogenous neurons) and significantly attenuate neurological functional defects in TBI mice. Combination of NSCs with OECs or VPA administration leads to overt improvement in axonal regeneration, synaptogenesis, and synaptic plasticity in the cerebral cortex in TBI-challenged mice, as shown by retrograde corticospinal tract tracing, electron microscopy, growth-associated protein 43 (GAP43), and synaptophysin (SYN) analyses. However, these beneficial effects of VPA are reversed by local delivery of N-methyl-D-aspartate (NMDA) into tissues surrounding the injury epicenter in the cerebral cortex, accompanied by a pronounced drop in axons and synapses in the brain. Our findings reveal that increased axonal regeneration and synaptogenesis evoked by cell grafting and VPA fosters neural repair in a murine model of TBI. Moreover, VPA-induced neuroprotective roles are antagonized by exogenous NMDA administration and its concomitant decrease in the number of neurons of local brain, indicating that increased neurons induced by VPA treatment mediate axonal regeneration and synaptogenesis in mice after TBI operation. Collectively, this study provides new insights into NSC transplantation therapy for TBI.
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Affiliation(s)
- Sujuan Liu
- Department of Anatomy and EmbryologySchool of Basic Medical ScienceTianjin Medical UniversityTianjin300070China
| | - Haili Tian
- School of KinesiologyShanghai University of SportShanghai200438China
| | - Yanmei Niu
- Department of RehabilitationSchool of Medical TechnologyTianjin Medical UniversityTianjin300070China
| | - Chunxia Yu
- Department of Physiology and PathophysiologySchool of Basic Medical ScienceTianjin Medical UniversityTianjin300070China
| | - Lingjian Xie
- Department of Physiology and PathophysiologySchool of Basic Medical ScienceTianjin Medical UniversityTianjin300070China
| | - Zhe Jin
- Tianjin Yaohua Binhai SchoolTianjin300000China
| | - Wenyan Niu
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of ImmunologySchool of Basic Medical ScienceTianjin Medical UniversityTianjin300070China
| | - Jun Ren
- Department of CardiologyZhongshan Hospital Fudan UniversityShanghai Institute of Cardiovascular DiseasesShanghai200032China,Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWA98195USA,Correspondence address. Tel: +86-22-83336819; (Z.Y.) / Tel: +86-22-83336107; (L.F.) / Tel: +86-21-64041990; (J.R.) @
| | - Li Fu
- Department of RehabilitationSchool of Medical TechnologyTianjin Medical UniversityTianjin300070China,Department of Physiology and PathophysiologySchool of Basic Medical ScienceTianjin Medical UniversityTianjin300070China,Correspondence address. Tel: +86-22-83336819; (Z.Y.) / Tel: +86-22-83336107; (L.F.) / Tel: +86-21-64041990; (J.R.) @
| | - Zhi Yao
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of ImmunologySchool of Basic Medical ScienceTianjin Medical UniversityTianjin300070China,Correspondence address. Tel: +86-22-83336819; (Z.Y.) / Tel: +86-22-83336107; (L.F.) / Tel: +86-21-64041990; (J.R.) @
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Nguyen H, Zhu W, Baltan S. Casein Kinase 2 Signaling in White Matter Stroke. Front Mol Biosci 2022; 9:908521. [PMID: 35911974 PMCID: PMC9325966 DOI: 10.3389/fmolb.2022.908521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/21/2022] [Indexed: 11/27/2022] Open
Abstract
The growth of the aging population, together with improved stroke care, has resulted in an increase in stroke survivors and a rise in recurrent events. Axonal injury and white matter (WM) dysfunction are responsible for much of the disability observed after stroke. The mechanisms of WM injury are distinct compared to gray matter and change with age. Therefore, an ideal stroke therapeutic must restore neuronal and axonal function when applied before or after a stroke, and it must also protect across age groups. Casein kinase 2 (CK2), is expressed in the brain, including WM, and is regulated during the development and numerous disease conditions such as cancer and ischemia. CK2 activation in WM mediates ischemic injury by activating the Cdk5 and AKT/GSK3β signaling pathways. Consequently, CK2 inhibition using the small molecule inhibitor CX-4945 (Silmitasertib) correlates with preservation of oligodendrocytes, conservation of axon structure, and axonal mitochondria, leading to improved functional recovery. Remarkably, CK2 inhibition promotes WM function when applied after ischemic injury by specifically regulating the AKT/GSK3β pathways. The blockade of the active conformation of AKT confers post-ischemic protection to young and old WM by preserving mitochondria, implying AKT as a common therapeutic target across age groups. Using a NanoString nCounter miRNA expression profiling, comparative analyses of ischemic WM with or without CX-4945 treatment reveal that miRNAs are expressed at high levels in WM after ischemia, and CX-4945 differentially regulates some of these miRNAs. Therefore, we propose that miRNA regulation may be one of the protective actions of CX-4945 against WM ischemic injury. Silmitasertib is FDA approved and currently in use for cancer and Covid patients; therefore, it is plausible to repurpose CK2 inhibitors for stroke patients.
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Affiliation(s)
| | | | - Selva Baltan
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, United States
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Kahveci FO, Kahveci R, Gokce EC, Gokce A, Kısa Ü, Sargon MF, Fesli R, Sarı MF, Gürer B. Biochemical, pathological and ultrastructural investigation of whether lamotrigine has neuroprotective efficacy against spinal cord ischemia reperfusion injury. Injury 2021; 52:2803-2812. [PMID: 34391576 DOI: 10.1016/j.injury.2021.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Lamotrigine, an anticonvulsant drug with inhibition properties of multi-ion channels, has been shown to be able to attenuates secondary neuronal damage by influencing different pathways. The aim of this study was to look into whether lamotrigine treatment could protect the spinal cord from experimental spinal cord ischemia-reperfusion injury. MATERIALS AND METHODS Thirty-two rats, eight rats per group, were randomly assigned to the sham group in which only laparotomy was performed, and to the ischemia, methylprednisolone and lamotrigine groups, where the infrarenal aorta was clamped for thirty minutes to induce spinal cord ischemia-reperfusion injury. Tissue samples belonging to spinal cords were harvested from sacrificed animals twenty-four hours after reperfusion. Tumor necrosis factor-alpha levels, interleukin-1 beta levels, nitric oxide levels, superoxide dismutase activity, catalase activity, glutathione peroxidase activity, malondialdehyde levels and caspase-3 activity were studied. Light and electron microscopic evaluations were also performed to reveal the pathological alterations. Basso, Beattie, and Bresnahan locomotor scale and the inclined-plane test was used to evaluate neurofunctional status at the beginning of the study and just before the animals were sacrificed. RESULTS Lamotrigine treatment provided significant improvement in the neurofunctional status by preventing the increase in cytokine expression, increased lipid peroxidation and oxidative stress, depletion of antioxidant enzymes activity and increased apoptosis, all of which contributing to spinal cord damage through different paths after ischemia reperfusion injury. Furthermore, lamotrigine treatment has shown improved results concerning the histopathological and ultrastructural scores and the functional tests. CONCLUSION These results proposed that lamotrigine may be a useful therapeutic agent to prevent the neuronal damage developing after spinal cord ischemia-reperfusion injury.
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Affiliation(s)
- Fatih Ozan Kahveci
- Department of Emergency Medicine, Balıkesir Atatürk City Hospital, Balıkesir, Turkey
| | - Ramazan Kahveci
- Department of Neurosurgery, Balıkesir University, Faculty of Medicine, Balıkesir, Turkey
| | - Emre Cemal Gokce
- Department of Neurosurgery, Abdurrahman Yurtaslan Ankara Oncology Education and Research Hospital, Ankara, Turkey
| | - Aysun Gokce
- Department of Pathology, Ministry of Health, Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey
| | - Üçler Kısa
- Department of Biochemistry, Kirikkale University, Faculty of Medicine, Kirikkale, Turkey
| | - Mustafa Fevzi Sargon
- Department of Anatomy, Lokman Hekim University, Faculty of Medicine, Ankara, Turkey
| | - Ramazan Fesli
- Department of Neurosurgery, Mersin VM Medical Park Hospital, Mersin, Turkey
| | - Muhammed Fatih Sarı
- Department of Neurosurgery, Balıkesir University, Faculty of Medicine, Balıkesir, Turkey
| | - Bora Gürer
- Department of Neurosurgery, İstinye University, Faculty of Medicine, Istanbul, Turkey.
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Combinatrial treatment of anti-High Mobility Group Box-1 monoclonal antibody and epothilone B improves functional recovery after spinal cord contusion injury. Neurosci Res 2021; 172:13-25. [PMID: 33864880 DOI: 10.1016/j.neures.2021.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 11/23/2022]
Abstract
Spinal cord injury (SCI) causes motor and sensory deficits and is currently considered an incurable disease. We have previously reported that administration of anti-High Mobility Group Box-1 monoclonal antibody (anti-HMGB1 mAb) preserved lesion area and improved locomotion recovery in mouse model of SCI. In order to further enhance the recovery, we here examined combinatorial treatment of anti-HMGB1 mAb and epothilone B (Epo B), which has been reported to promote axon regeneration. This combinatorial treatment significantly increased hindlimb movement compared with anti-HMGB1 mAb alone, although Epo B alone failed to increase functional recovery. These results are in agreement with that anti-HMGB1 mAb alone was able to decrease the lesion area spreading and increase the surviving neuron numbers around the lesion, whereas Epo B facilitated axon outgrowth only in combination with anti-HMGB1 mAb, suggesting that anti-HMGB1 mAb-dependent tissue preservation is necessary for Epo B to exhibit its therapeutic effect. Taken together, the combinatorial treatment can be considered as a novel and clinically applicable strategy for SCI.
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Daverey A, Agrawal SK. Regulation of Prdx6 by Nrf2 Mediated Through aiPLA2 in White Matter Reperfusion Injury. Mol Neurobiol 2021; 58:1275-1289. [PMID: 33159299 DOI: 10.1007/s12035-020-02182-z] [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: 07/17/2020] [Accepted: 10/18/2020] [Indexed: 12/18/2022]
Abstract
Hypoxia and reperfusion produces overproduction of ROS (reactive oxygen species), which may lead to mitochondrial dysfunction leading to cell death and apoptosis. Here, we explore the hypothesis that Prdx6 protects the spinal cord white matter from hypoxia-reperfusion injury and elucidate the possible mechanism by which Prdx6 elicits its protective effects. Briefly, rats were deeply anesthetized with isoflurane. A 30-mm section of the spinal cord was rapidly removed and placed in cold Ringer's solution (2-4 °C). The dissected dorsal column was exposed to hypoxia with 95% N2 and 5% CO2 and reperfusion with 95% O2 and 5% CO2. The expression of Prdx6 significantly upregulated in white matter after hypoxia compared to the sham group, whereas reperfusion caused a gradual decrease in Prdx6 expression after reperfusion injury. For the first time, our study revealed the novel expression and localized expression of Prdx6 in astrocytes after hypoxia, and possible communication of astrocytes and axons through Prdx6. The gradual increase in Nrf2 expression suggests a negative regulation of Prdx6 through Nrf2 signaling. Furthermore, inhibition of aiPLA2 activity of Prdx6 by MJ33 shows that the regulation of Prdx6 by Nrf2 is mediated through aiPLA2 activity. The present study uncovers a differential distribution of Prdx6 in axons and astrocytes and regulation of Prdx6 in hypoxia-reperfusion injury. The low levels of Prdx6 in reperfusion injury lead to increased inflammation and apoptosis in the white matter; therefore, the results of this study suggest that Prdx6 has a protective role in spinal hypoxia-reperfusion injury.
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Affiliation(s)
- Amita Daverey
- Department of Neurosurgery, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA.
| | - Sandeep K Agrawal
- Department of Neurosurgery, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA
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Gouvêa-Junqueira D, Falvella ACB, Antunes ASLM, Seabra G, Brandão-Teles C, Martins-de-Souza D, Crunfli F. Novel Treatment Strategies Targeting Myelin and Oligodendrocyte Dysfunction in Schizophrenia. Front Psychiatry 2020; 11:379. [PMID: 32425837 PMCID: PMC7203658 DOI: 10.3389/fpsyt.2020.00379] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/15/2020] [Indexed: 12/12/2022] Open
Abstract
Oligodendrocytes are the glial cells responsible for the formation of the myelin sheath around axons. During neurodevelopment, oligodendrocytes undergo maturation and differentiation, and later remyelination in adulthood. Abnormalities in these processes have been associated with behavioral and cognitive dysfunctions and the development of various mental illnesses like schizophrenia. Several studies have implicated oligodendrocyte dysfunction and myelin abnormalities in the disorder, together with altered expression of myelin-related genes such as Olig2, CNP, and NRG1. However, the molecular mechanisms subjacent of these alterations remain elusive. Schizophrenia is a severe, chronic psychiatric disorder affecting more than 23 million individuals worldwide and its symptoms usually appear at the beginning of adulthood. Currently, the major therapeutic strategy for schizophrenia relies on the use of antipsychotics. Despite their widespread use, the effects of antipsychotics on glial cells, especially oligodendrocytes, remain unclear. Thus, in this review we highlight the current knowledge regarding oligodendrocyte dysfunction in schizophrenia, compiling data from (epi)genetic studies and up-to-date models to investigate the role of oligodendrocytes in the disorder. In addition, we examined potential targets currently investigated for the improvement of schizophrenia symptoms. Research in this area has been investigating potential beneficial compounds, including the D-amino acids D-aspartate and D-serine, that act as NMDA receptor agonists, modulating the glutamatergic signaling; the antioxidant N-acetylcysteine, a precursor in the synthesis of glutathione, protecting against the redox imbalance; as well as lithium, an inhibitor of glycogen synthase kinase 3β (GSK3β) signaling, contributing to oligodendrocyte survival and functioning. In conclusion, there is strong evidence linking oligodendrocyte dysfunction to the development of schizophrenia. Hence, a better understanding of oligodendrocyte differentiation, as well as the effects of antipsychotic medication in these cells, could have potential implications for understanding the development of schizophrenia and finding new targets for drug development.
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Affiliation(s)
- Danielle Gouvêa-Junqueira
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Ana Caroline Brambilla Falvella
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - André Saraiva Leão Marcelo Antunes
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Gabriela Seabra
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Caroline Brandão-Teles
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Daniel Martins-de-Souza
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Experimental Medicine Research Cluster (EMRC), University of Campinas, Campinas, Brazil
- Instituto Nacional de Biomarcadores em Neuropsiquiatria, Conselho Nacional de Desenvolvimento Científico e Tecnológico, São Paulo, Brazil
- D′Or Institute for Research and Education (IDOR), São Paulo, Brazil
| | - Fernanda Crunfli
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
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Scott GA, Roebuck AJ, Greba Q, Howland JG. Performance of the trial-unique, delayed non-matching-to-location (TUNL) task depends on AMPA/Kainate, but not NMDA, ionotropic glutamate receptors in the rat posterior parietal cortex. Neurobiol Learn Mem 2019; 159:16-23. [DOI: 10.1016/j.nlm.2019.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/04/2018] [Accepted: 02/03/2019] [Indexed: 02/06/2023]
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Level-Specific Differences in Systemic Expression of Pro- and Anti-Inflammatory Cytokines and Chemokines after Spinal Cord Injury. Int J Mol Sci 2018; 19:ijms19082167. [PMID: 30044384 PMCID: PMC6122077 DOI: 10.3390/ijms19082167] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 07/23/2018] [Accepted: 07/23/2018] [Indexed: 11/17/2022] Open
Abstract
While over half of all spinal cord injuries (SCIs) occur in the cervical region, the majority of preclinical studies have focused on models of thoracic injury. However, these two levels are anatomically distinct—with the cervical region possessing a greater vascular supply, grey-white matter ratio and sympathetic outflow relative to the thoracic region. As such, there exists a significant knowledge gap in the secondary pathology at these levels following SCI. In this study, we characterized the systemic plasma markers of inflammation over time (1, 3, 7, 14, 56 days post-SCI) after moderate-severe, clip-compression cervical and thoracic SCI in a rat model. Using high-throughput ELISA panels, we observed a clear level-specific difference in plasma levels of VEGF, leptin, IP10, IL18, GCSF, and fractalkine. Overall, cervical SCI had reduced expression of both pro- and anti-inflammatory proteins relative to thoracic SCI, likely due to sympathetic dysregulation associated with higher level SCIs. However, contrary to the literature, we did not observe level-dependent splenic atrophy with our incomplete SCI model. This is the first study to compare the systemic plasma-level changes following cervical and thoracic SCI using level-matched and time-matched controls. The results of this study provide the first evidence in support of level-targeted intervention and also challenge the phenomenon of high SCI-induced splenic atrophy in incomplete SCI models.
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Choi BY, Jung JW, Suh SW. The Emerging Role of Zinc in the Pathogenesis of Multiple Sclerosis. Int J Mol Sci 2017; 18:E2070. [PMID: 28956834 PMCID: PMC5666752 DOI: 10.3390/ijms18102070] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 09/21/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022] Open
Abstract
Our lab has previously demonstrated that multiple sclerosis-induced spinal cord white matter damage and motor deficits are mediated by the pathological disruption of zinc homeostasis. Abnormal vesicular zinc release and intracellular zinc accumulation may mediate several steps in the pathophysiological processes of multiple sclerosis (MS), such as matrix metallopeptidase 9 (MMP-9) activation, blood-brain barrier (BBB) disruption, and subsequent immune cell infiltration from peripheral systems. Oral administration of a zinc chelator decreased BBB disruption, immune cell infiltration, and spinal white matter myelin destruction. Therefore, we hypothesized that zinc released into the extracellular space during MS progression is involved in destruction of the myelin sheath in spinal cord white mater and in generation of motor deficits. To confirm our previous study, we employed zinc transporter 3 (ZnT3) knockout mice to test whether vesicular zinc depletion shows protective effects on multiple sclerosis-induced white matter damage and motor deficits. ZnT3 gene deletion profoundly reduced the daily clinical score of experimental autoimmune encephalomyelitis (EAE) by suppression of inflammation and demyelination in the spinal cord. ZnT3 gene deletion also remarkably inhibited formation of multiple sclerosis-associated aberrant synaptic zinc patches, MMP-9 activation, and BBB disruption. These two studies strongly support our hypothesis that zinc release from presynaptic terminals may be involved in multiple sclerosis pathogenesis. Further studies will no doubt continue to add mechanistic detail to this process and with luck, clarify how these observations may lead to development of novel therapeutic approaches for the treatment of multiple sclerosis.
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Affiliation(s)
- Bo Young Choi
- Department of Physiology, Hallym University, College of Medicine, Chuncheon 24252, Korea.
| | - Jong Won Jung
- Department of Physiology, Hallym University, College of Medicine, Chuncheon 24252, Korea.
| | - Sang Won Suh
- Department of Physiology, Hallym University, College of Medicine, Chuncheon 24252, Korea.
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A Novel Approach for Studying the Physiology and Pathophysiology of Myelinated and Non-Myelinated Axons in the CNS White Matter. PLoS One 2016; 11:e0165637. [PMID: 27829055 PMCID: PMC5102346 DOI: 10.1371/journal.pone.0165637] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/14/2016] [Indexed: 11/19/2022] Open
Abstract
Advances in brain connectomics set the need for detailed knowledge of functional properties of myelinated and non-myelinated (if present) axons in specific white matter pathways. The corpus callosum (CC), a major white matter structure interconnecting brain hemispheres, is extensively used for studying CNS axonal function. Unlike another widely used CNS white matter preparation, the optic nerve where all axons are myelinated, the CC contains also a large population of non-myelinated axons, making it particularly useful for studying both types of axons. Electrophysiological studies of optic nerve use suction electrodes on nerve ends to stimulate and record compound action potentials (CAPs) that adequately represent its axonal population, whereas CC studies use microelectrodes (MEs), recording from a limited area within the CC. Here we introduce a novel robust isolated "whole" CC preparation comparable to optic nerve. Unlike ME recordings where the CC CAP peaks representing myelinated and non-myelinated axons vary broadly in size, "whole" CC CAPs show stable reproducible ratios of these two main peaks, and also reveal a third peak, suggesting a distinct group of smaller caliber non-myelinated axons. We provide detailed characterization of "whole" CC CAPs and conduction velocities of myelinated and non-myelinated axons along the rostro-caudal axis of CC body and show advantages of this preparation for comparing axonal function in wild type and dysmyelinated shiverer mice, studying the effects of temperature dependence, bath-applied drugs and ischemia modeled by oxygen-glucose deprivation. Due to the isolation from gray matter, our approach allows for studying CC axonal function without possible "contamination" by reverberating signals from gray matter. Our analysis of "whole" CC CAPs revealed higher complexity of myelinated and non-myelinated axonal populations, not noticed earlier. This preparation may have a broad range of applications as a robust model for studying myelinated and non-myelinated axons of the CNS in various experimental models.
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Kanter M, Coskun O, Kalayci M, Buyukbas S, Cagavi F. Neuroprotective effects of Nigella sativa on experimental spinal cord injury in rats. Hum Exp Toxicol 2016; 25:127-33. [PMID: 16634331 DOI: 10.1191/0960327106ht608oa] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of this study was to investigate the possible beneficial effects of Nigella sativa (NS) in comparison to methylprednisolone on experimental spinal cord injury (SCI) in rats. SCI was performed by placing an aneurysm clip extradurally at the level of T11-12. Rats were neurologically tested over 24 h after trauma and spinal cord tissue samples were harvested for both biochemical and histopathological evaluation. The neurological scores of rats were not found to be different in SCI groups. SCI significantly increased the spinal cord tissue malondialdehyde (MDA) and protein carbonyl (PC) levels, however SCI decreased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) enzyme activities compared to the control. Methylprednisolone and NS treatment decreased tissue MDA and PC levels and prevented inhibition of SOD, GSH-Px and CAT enzymes in the tissues. The most significant results were obtained when NS was given. In SCI and placebo groups, the neurons of spinal cord tissue became extensively dark and degenerated with picnotic nuclei. The morphology of neurons in methylprednisolone and NS-treated groups were well protected, however, not as well as the neurons of the control group. The number of neurons in the spinal cord tissue of the SCI and placebo groups was significantly less than the control, laminectomy, methylprednisolone and NS-treated groups. In conclusion, NS treatment might be beneficial in spinal cord tissue damage, and therefore shows potential for clinical implications.
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Affiliation(s)
- M Kanter
- Department of Histology-Embryology, Faculty of Medicine, Trakya University, Edirne, Turkey.
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Abstract
White matter of the brain and spinal cord is irreversibly damaged by ischemia and trauma. Recent evidence indicates that despite the absence of synaptic elements, excitotoxic mechanisms play an important role in the pathogenesis of white matter damage. Glial cells, including astrocytes and oligodendrocytes, possess non-NMDA glutamate receptors and are injured by excessive exposure to AMPA/kainate agonists. In addition, the myelin sheath itself appears to respond directly to glutamate stimulation via AMPA receptors, which may also lead to injury of this key constituent of myelinated axons. During white matter anoxia/ischemia or trauma, endogenous glutamate is released mainly from axoplasmic pools in a nonvesicular fashion through Na+-dependent glutamate transporters, stimulated to operate in the glutamate efflux mode by collapse of transmembrane ion gradients and depolarization. It appears that parallel mechanisms are triggered by injurious stimuli, involving reverse Na+-Ca2+ exchange and voltage-gated Ca2+ channels producing Ca2+ overload of the axon cylinder, whereas glutamate release with AMPA receptor overactivation causes Ca2+-dependent damage to the ensheathing myelin and sup-porting glia. The emerging complexity of white matter injury mechanisms requires a thorough understanding of the interrelated steps to optimize therapeutic design.
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Affiliation(s)
- Peter K. Stys
- Division of Neuroscience, Loeb Health Research Institute, Ottawa Hospital-Civic Campus, University of Ottawa, Ottawa, Ontario, Canada,
| | - Shuxin Li
- Division of Neuroscience, Loeb Health Research Institute, Ottawa Hospital-Civic Campus, University of Ottawa, Ottawa, Ontario, Canada
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Hamilton NB, Kolodziejczyk K, Kougioumtzidou E, Attwell D. Proton-gated Ca(2+)-permeable TRP channels damage myelin in conditions mimicking ischaemia. Nature 2016; 529:523-7. [PMID: 26760212 PMCID: PMC4733665 DOI: 10.1038/nature16519] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/07/2015] [Indexed: 11/09/2022]
Abstract
The myelin sheaths wrapped around axons by oligodendrocytes are crucial for brain function. In ischaemia myelin is damaged in a Ca(2+)-dependent manner, abolishing action potential propagation. This has been attributed to glutamate release activating Ca(2+)-permeable N-methyl-D-aspartate (NMDA) receptors. Surprisingly, we now show that NMDA does not raise the intracellular Ca(2+) concentration ([Ca(2+)]i) in mature oligodendrocytes and that, although ischaemia evokes a glutamate-triggered membrane current, this is generated by a rise of extracellular [K(+)] and decrease of membrane K(+) conductance. Nevertheless, ischaemia raises oligodendrocyte [Ca(2+)]i, [Mg(2+)]i and [H(+)]i, and buffering intracellular pH reduces the [Ca(2+)]i and [Mg(2+)]i increases, showing that these are evoked by the rise of [H(+)]i. The H(+)-gated [Ca(2+)]i elevation is mediated by channels with characteristics of TRPA1, being inhibited by ruthenium red, isopentenyl pyrophosphate, HC-030031, A967079 or TRPA1 knockout. TRPA1 block reduces myelin damage in ischaemia. These data suggest that TRPA1-containing ion channels could be a therapeutic target in white matter ischaemia.
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Affiliation(s)
- Nicola B Hamilton
- Department of Neuroscience, Physiology &Pharmacology, University College London, Gower St., London WC1E 6BT, UK
| | - Karolina Kolodziejczyk
- Department of Neuroscience, Physiology &Pharmacology, University College London, Gower St., London WC1E 6BT, UK
| | - Eleni Kougioumtzidou
- Department of Neuroscience, Physiology &Pharmacology, University College London, Gower St., London WC1E 6BT, UK
| | - David Attwell
- Department of Neuroscience, Physiology &Pharmacology, University College London, Gower St., London WC1E 6BT, UK
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Ahmad AS, Satriotomo I, Fazal J, Nadeau SE, Doré S. Considerations for the Optimization of Induced White Matter Injury Preclinical Models. Front Neurol 2015; 6:172. [PMID: 26322013 PMCID: PMC4532913 DOI: 10.3389/fneur.2015.00172] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/20/2015] [Indexed: 11/13/2022] Open
Abstract
White matter (WM) injury in relation to acute neurologic conditions, especially stroke, has remained obscure until recently. Current advances in imaging technologies in the field of stroke have confirmed that WM injury plays an important role in the prognosis of stroke and suggest that WM protection is essential for functional recovery and post-stroke rehabilitation. However, due to the lack of a reproducible animal model of WM injury, the pathophysiology and mechanisms of this injury are not well studied. Moreover, producing selective WM injury in animals, especially in rodents, has proven to be challenging. Problems associated with inducing selective WM ischemic injury in the rodent derive from differences in the architecture of the brain, most particularly, the ratio of WM to gray matter in rodents compared to humans, the agents used to induce the injury, and the location of the injury. Aging, gender differences, and comorbidities further add to this complexity. This review provides a brief account of the techniques commonly used to induce general WM injury in animal models (stroke and non-stroke related) and highlights relevance, optimization issues, and translational potentials associated with this particular form of injury.
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Affiliation(s)
- Abdullah Shafique Ahmad
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA
| | - Irawan Satriotomo
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA
| | - Jawad Fazal
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA
| | - Stephen E Nadeau
- Research Service, Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Medical Center , Gainesville, FL , USA ; Department of Neurology, University of Florida , Gainesville, FL , USA
| | - Sylvain Doré
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA ; Research Service, Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Medical Center , Gainesville, FL , USA ; Department of Neurology, University of Florida , Gainesville, FL , USA ; Department of Neuroscience, University of Florida , Gainesville, FL , USA ; Department of Neurology, University of Florida , Gainesville, FL , USA ; Department of Pharmaceutics, University of Florida , Gainesville, FL , USA ; Department of Psychology, University of Florida , Gainesville, FL , USA ; Department of Psychiatry, University of Florida , Gainesville, FL , USA
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Dai J, Lin H, Niu S, Wu X, Wu Y, Zhang H. Correlation of bone fragments reposition and related parameters in thoracolumbar burst fractures patients. Int J Clin Exp Med 2015; 8:11125-11131. [PMID: 26379913 PMCID: PMC4565296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/09/2015] [Indexed: 06/05/2023]
Abstract
The aim of this study is to determine if thoracolumbar vertebral body collapse or canal compromise (CC) is associated with reposition of bone fragment. We retrospective review medical charts of patients with thoracolumbar burst fractures from July 2010 to September 2013. The fractures were classified according to the Arbeit Fuer Osteoosynthese (AO) classification system. Neurological status was classified according to American Spinal Injury Association (ASIA). Patients were divided into two groups (reposition group and non-reposition group) according to whether the bone fragments were reposition or non-reposition after surgery. Mimics measured mid-sagittal canal diameter (MSD), transverse canal diameter (TCD), local kyphosis (LK) and calculated anterior vertebral body compression ratio (AVBCR), middle vertebral body compression ratio (MVBCR), posterior vertebral body compression ratio (PVBCR), and mid-sagittal canal diameter compression ratio (MSDCR) on the preoperative CT image. The results indicated that 55 patients were included in the study. There are 35 patients with reposition of bone fragment and 20 patients with non-reposition of bone fragment after surgery. There were significant difference on MSD (t = 3.258, P = 0.002), TCD (t = 2.197, P = 0.032), AVBCR (t = -2.063, P = 0.044), MVBCR (t = -2.526, P = 0.015), PVBCR (t = -2.211, P = 0.031), MSDCR (t = -4.975, P = 0.000) between two groups before surgery. There was a significant correlation between reposition of bone fragment and AO classification (OR = 5.251, P = 0.022), and MSDCR (OR = 7.366, P = 0.007). There was no significant correlation between reposition and AVBCR, MVBCR, PVBCR, LK, MSD and TCD. In conclusion, this study indicates that AO classification and MSDCR are predictors of reposition of bone fragment.
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Affiliation(s)
- Jianhui Dai
- Department of Orthopedics, Affiliated Hospital of Putian UniversityFujian 351100, China
| | - Haibin Lin
- Department of Orthopedics, Affiliated Hospital of Putian UniversityFujian 351100, China
| | - Susheng Niu
- College of Orthopedic Institute, Fujian University of Traditional Chinese MedicineFujian 350001, China
| | - Xianwei Wu
- Department of Orthopedics, Affiliated Hospital of Putian UniversityFujian 351100, China
| | - Yujun Wu
- Department of Orthopedics, Affiliated Hospital of Putian UniversityFujian 351100, China
| | - Huaizhi Zhang
- Department of Orthopedics, Affiliated Hospital of Putian UniversityFujian 351100, China
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Siddiqui AM, Khazaei M, Fehlings MG. Translating mechanisms of neuroprotection, regeneration, and repair to treatment of spinal cord injury. PROGRESS IN BRAIN RESEARCH 2015; 218:15-54. [PMID: 25890131 DOI: 10.1016/bs.pbr.2014.12.007] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the big challenges in neuroscience that remains to be understood is why the central nervous system is not able to regenerate to the extent that the peripheral nervous system does. This is especially problematic after traumatic injuries, like spinal cord injury (SCI), since the lack of regeneration leads to lifelong deficits and paralysis. Treatment of SCI has improved during the last several decades due to standardized protocols for emergency medical response teams and improved medical, surgical, and rehabilitative treatments. However, SCI continues to result in profound impairments for the individual. There are many processes that lead to the pathophysiology of SCI, such as ischemia, vascular disruption, neuroinflammation, oxidative stress, excitotoxicity, demyelination, and cell death. Current treatments include surgical decompression, hemodynamic control, and methylprednisolone. However, these early treatments are associated with modest functional recovery. Some treatments currently being investigated for use in SCI target neuroprotective (riluzole, minocycline, G-CSF, FGF-2, and polyethylene glycol) or neuroregenerative (chondroitinase ABC, self-assembling peptides, and rho inhibition) strategies, while many cell therapies (embryonic stem cells, neural stem cells, induced pluripotent stem cells, mesenchymal stromal cells, Schwann cells, olfactory ensheathing cells, and macrophages) have also shown promise. However, since SCI has multiple factors that determine the progress of the injury, a combinatorial therapeutic approach will most likely be required for the most effective treatment of SCI.
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Affiliation(s)
- Ahad M Siddiqui
- Department of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Mohamad Khazaei
- Department of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Department of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
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Hu Z, Zhou Y, Li N, Xie X. Correlations between posterior longitudinal ligament status and size of bone fragment in thoracolumbar burst fractures. Int J Clin Exp Med 2015; 8:2754-2759. [PMID: 25932230 PMCID: PMC4402877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/17/2015] [Indexed: 06/04/2023]
Abstract
This study aim to determine the correlation between the size of bone fragment and injury of posterior longitudinal ligament (PLL). In this study retrospectively analyze medical chart of patients with thoracolumbar burst fractures from June 2010 to December 2012. Patients were divided into two groups (Intact group and Disrupted group) according to the result of MRI assessing status of PLL. All the fractures were classified according to the Arbeit Fuer Osteoosynthese (AO) classification system. Neurological status was classified according to American Spinal Injury Association (ASIA). Mimics measured the height and width of bone fragment (HBF and WBF), transverse canal diameter (TCD) and calculate the height of posterior wall of the injury vertebrae, ratio of height of bone fragment occupying height of posterior wall of vertebrae body (RHBF) and ratio of width of bone fragment occupying transverse canal diameter (RWBF). The results indicated that 52 patients were included in the study. There are 31 patients with intact PLL and 21 patients with disrupted PLL. There was significant difference on the HBF (t = -3.646, P = 0.001), WBF (t = -3.615, P = 0.001), RHBF (t = -4.124, P = 0.000) and RWBF (t = -3.305, P = 0.002) between the intact group and injury group. There was a significant correlation between injury of PLL and ASIA grade (OR = 7.851, P = 0.005), and AO classification (OR = 6.401, P = 0.011), and RHBF (OR = 6.455, P = 0.011), and HBF (OR = 5.208, P = 0.022). In conclusion, the results of this study indicate that AO classification, ASIA grade, HBF and RHBF could act as the predictors of injury of PLL.
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Affiliation(s)
- Zhaohui Hu
- Department of Orthopedics, Liuzhou People's Hospital No. 8, Wenchang Road, Liuzhou 545006, Guangxi Province, China
| | - Yanhong Zhou
- Department of Orthopedics, Liuzhou People's Hospital No. 8, Wenchang Road, Liuzhou 545006, Guangxi Province, China
| | - Ningning Li
- Department of Orthopedics, Liuzhou People's Hospital No. 8, Wenchang Road, Liuzhou 545006, Guangxi Province, China
| | - Xiangtao Xie
- Department of Orthopedics, Liuzhou People's Hospital No. 8, Wenchang Road, Liuzhou 545006, Guangxi Province, China
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Melatonin improves functional outcome via inhibition of matrix metalloproteinases-9 after photothrombotic spinal cord injury in rats. Acta Neurochir (Wien) 2014; 156:2173-82. [PMID: 24879621 DOI: 10.1007/s00701-014-2119-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/29/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9 play an important role in secondary inflammatory reaction and blood-central nervous system (CNS) barrier disruption after spinal cord injury (SCI). Theoretically, it is expected that early blockade of activation of MMPs can provide neuro-protective effects from secondary tissue damage and improve functional neurological outcomes. The aim of this study was to investigate the expression and the activity of MMP-2 and MMP-9, and to determine the regulatory effect of melatonin on MMP expression and activity after photochemically induced SCI in rats. METHODS Female Sprague-Dawley rats weighing between 250 and 300 g (age 8 weeks) received focal ischemia by photothrombosis using Rose Bengal (RB). The injured animals were divided into two groups; one group received 50 mg/kg of melatonin intraperitoneally, starting 1 h after injury and at 12 h intervals for 7 days, while animals in the control group received weight-adjusted doses of a saline vehicle. In each group, the expressions and activities of MMP-2 and MMP-9 were assessed by Western blot and gelatin zymography at various times from 6 h to 3 days. The locomotor function was assessed using the Basso-Beattie-Bresnahan (BBB) scale at 3 days after SCI and then once per week for 4 weeks. The animals were killed at 28 days after the injury, and the histopathology of the lesions was assessed. FINDINGS The expressions and activities of MMP-9 were increased at 6, 24, 48, and 72 h after SCI in the control group. In the melatonin-treated group, the expression of MMP-9 was significantly decreased at 24, 48, and 72 h after SCI compared with the control group, and the activity of MMP-9 was significantly reduced at 72 h after SCI. In contrast, there were no significant changes in the MMP-2 level in both groups during the experimental period. Melatonin treatment following photochemically induced SCI in rats significantly ameliorated the functional deficits. On histopathologic examination, the lesion size in the spinal cord after photothrombotic insult was significantly reduced by melatonin administration. CONCLUSIONS This study showed that the up-regulation of MMP-9 correlated with the secondary damage after SCI in rats. The results of this study suggest that the ability of melatonin to reduce secondary tissue damage is intimately related to the reduction of MMP-9 expression, resulting in functional improvement.
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Goncharenko K, Eftekharpour E, Velumian AA, Carlen PL, Fehlings MG. Changes in gap junction expression and function following ischemic injury of spinal cord white matter. J Neurophysiol 2014; 112:2067-75. [PMID: 25080569 DOI: 10.1152/jn.00037.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gap junctions are widely present in spinal cord white matter; however, their role in modulating the dynamics of axonal dysfunction remains largely unexplored. We hypothesized that inhibition of gap junctions reduces the loss of axonal function during oxygen and glucose deprivation (OGD). The functional role of gap junctions was assessed by electrophysiological recordings of compound action potentials (CAPs) in Wistar rat spinal cord slices with the sucrose gap technique. The in vitro slices were subjected to 30-min OGD. Gap junction connexin (Cx) mRNA expression was determined by qPCR and normalized to β-actin. A 30-min OGD resulted in reduction of CAPs to 14.8 ± 4.6% of their pre-OGD amplitude (n = 5). In the presence of gap junction blockers carbenoxolone (Cbx; 100 μM) and 1-octanol (Oct; 300 μM), the CAP reduction in OGD was to only 35.7 ± 5.7% of pre-OGD amplitude in Cbx (n = 9) and to 37.4 ± 8.9% of pre-OGD amplitude in Oct (n = 10). Both drugs also noticeably prolonged the half-decline time of CAP amplitudes in OGD from 6.0 min in no-drug conditions to 9.6 min in the presence of Cbx and to 7.7 min in the presence of Oct, suggesting that blocking gap junctions reduces conduction loss during OGD. With application of Cbx and Oct in the setting of OGD, expression of Cx30 and Cx43 mRNA was downregulated. Our data provide new insights into the role of gap junctions in white matter ischemia and reveal the necessity of a cautious approach in determining detrimental or beneficial effects of gap junction blockade in white matter ischemia.
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Affiliation(s)
- Karina Goncharenko
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Departments of Physiology and
| | - Eftekhar Eftekharpour
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Alexander A Velumian
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Departments of Physiology and Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Peter L Carlen
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Departments of Physiology and
| | - Michael G Fehlings
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Surgery, University of Toronto, Toronto, Ontario, Canada
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TENS augments blood flow in somatotopically linked spinal cord segments and mitigates compressive ischemia. Spinal Cord 2014; 52:744-8. [PMID: 25047054 DOI: 10.1038/sc.2014.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/29/2014] [Accepted: 06/18/2014] [Indexed: 11/08/2022]
Abstract
STUDY DESIGN This was an acute basic physiological study in anesthetized adult male rats. OBJECTIVES The purpose of this study was to determine, in an animal model, whether innocuous somatic stimulation, in the form of transcutaneous electrical nerve stimulation (TENS), could produce a sustained augmentation of spinal cord blood flow, and whether this effect was robust in the face of relatively mild, non-destructive compression of the spinal cord. SETTING Neurophysiology laboratory, Canadian Memorial Chiropractic College, Toronto, Canada. METHODS In anesthetized adult male Wistar rats, spinal cord blood flow was measured with laser Doppler flowmetry during 5- and 15-min epochs of TENS stimulation in uncompressed and compressed lumbar spinal cord. RESULTS TENS applied to the L4/L5 dermatomes was associated with augmentation of blood flow in somatotopically linked spinal cord segments. This augmentation was robust in the face of non-destructive compression of the spinal cord, was sustained for periods of stimulation up to 15 min and occurred in the absence of any change in the mean arterial blood pressure. CONCLUSIONS TENS augments spinal cord blood flow in the uncompressed spinal cord and during acute, non-destructive spinal cord compression. It remains to be seen whether similar results can be achieved in chronically compressed spinal cord and spinal nerve roots, and whether these results have clinical implications in human syndromes of spinal cord compression.
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Silva NA, Sousa N, Reis RL, Salgado AJ. From basics to clinical: a comprehensive review on spinal cord injury. Prog Neurobiol 2013; 114:25-57. [PMID: 24269804 DOI: 10.1016/j.pneurobio.2013.11.002] [Citation(s) in RCA: 526] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 11/12/2013] [Accepted: 11/12/2013] [Indexed: 12/15/2022]
Abstract
Spinal cord injury (SCI) is a devastating neurological disorder that affects thousands of individuals each year. Over the past decades an enormous progress has been made in our understanding of the molecular and cellular events generated by SCI, providing insights into crucial mechanisms that contribute to tissue damage and regenerative failure of injured neurons. Current treatment options for SCI include the use of high dose methylprednisolone, surgical interventions to stabilize and decompress the spinal cord, and rehabilitative care. Nonetheless, SCI is still a harmful condition for which there is yet no cure. Cellular, molecular, rehabilitative training and combinatorial therapies have shown promising results in animal models. Nevertheless, work remains to be done to ascertain whether any of these therapies can safely improve patient's condition after human SCI. This review provides an extensive overview of SCI research, as well as its clinical component. It starts covering areas from physiology and anatomy of the spinal cord, neuropathology of the SCI, current clinical options, neuronal plasticity after SCI, animal models and techniques to assess recovery, focusing the subsequent discussion on a variety of promising neuroprotective, cell-based and combinatorial therapeutic approaches that have recently moved, or are close, to clinical testing.
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Affiliation(s)
- Nuno A Silva
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Rui L Reis
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909 Caldas das Taipas, Guimarães, Portugal
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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Larsson M, Agalave N, Watanabe M, Svensson C. Distribution of transmembrane AMPA receptor regulatory protein (TARP) isoforms in the rat spinal cord. Neuroscience 2013; 248:180-93. [DOI: 10.1016/j.neuroscience.2013.05.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 05/13/2013] [Accepted: 05/31/2013] [Indexed: 02/08/2023]
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Johnstone JT, Morton PD, Jayakumar AR, Bracchi-Ricard V, Runko E, Liebl DJ, Norenberg MD, Bethea JR. Reduced extracellular zinc levels facilitate glutamate-mediated oligodendrocyte death after trauma. J Neurosci Res 2013; 91:828-37. [PMID: 23553703 DOI: 10.1002/jnr.23208] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 12/17/2012] [Accepted: 01/03/2013] [Indexed: 12/18/2022]
Abstract
Spinal cord injury results in irreversible paralysis, axonal injury, widespread oligodendrocyte death, and white matter damage. Although the mechanisms underlying these phenomena are poorly understood, previous studies from our laboratory indicate that inhibiting activation of the nuclear factor-κB transcription factor in astrocytes reduces white matter damage and improves functional recovery following spinal cord injury. In the current study, we demonstrate that activation of the nuclear factor-κB transcription factor within astrocytes results in a significant increase in oligodendrocyte death following trauma by reducing extracellular zinc levels and inducing glutamate excitotoxicity. By using an ionotropic glutamate receptor antagonist (CNQX), we show that astroglial nuclear factor-κB-mediated oligodendrocyte death is dependent on glutamate signaling despite no change in extracellular glutamate concentrations. Further analysis demonstrated a reduction in levels of extracellular zinc in astrocyte cultures with functional nuclear factor-κB signaling following trauma. Cotreatment of oligodendrocytes with glutamate and zinc showed a significant increase in oligodendrocyte toxicity under low-zinc conditions, suggesting that the presence of zinc at specific concentrations can prevent glutamate excitotoxicity. These studies demonstrate a novel role for zinc in regulating oligodendrocyte excitotoxicity and identify new therapeutic targets to prevent oligodendrocyte cell death in central nervous system trauma and disease.
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Affiliation(s)
- Joshua T Johnstone
- The Miami Project To Cure Paralysis, University of Miami, Miami, Florida 33136, USA
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Kesherwani V, Atif F, Yousuf S, Agrawal SK. Resveratrol protects spinal cord dorsal column from hypoxic injury by activating Nrf-2. Neuroscience 2013; 241:80-8. [PMID: 23523995 DOI: 10.1016/j.neuroscience.2013.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/12/2013] [Accepted: 03/08/2013] [Indexed: 01/20/2023]
Abstract
Damage from oxidative stress plays a critical role in spinal cord injury. Nuclear factor erythroid 2-related factor (Nrf-2) signaling pathway can be activated by cellular oxidative stress. Resveratrol, a plant-derived polyphenolic compound found in red wine, has antioxidant properties. In the present study, we have examined the neuroprotective effect of resveratrol and the role of Nrf-2 in spinal cord hypoxic injury. The spinal cord was removed from adult male Wistar rats from T2-T10 and the dorsal column was used to induce hypoxic injury in vitro with and without treatment with resveratrol (50μM). Significant changes were found in the compound action potential (CAP) of spinal cord dorsal column, and hematoxyline and eosin (H&E) staining showed that resveratrol significantly improved neuronal injury. The biochemical assays showed significant changes in lipid peroxidase (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), protein carbonyl (PC), mitochondrial ATP content, and mitochondrial Ca(++). Furthermore, using immunohistochemistry and Western blot, we found that after resveratrol treatment during hypoxic injury there was a significant activation of NrF-2 and down regulation of the glial fibrillary acidic protein (GFAP) content. The results show that resveratrol treatment has neuroprotective effects on CAP, Ca(++) loading, and biochemical parameters after hypoxic injury. The neuroprotective effect is likely to be exerted by increased activation of transcription factor Nrf-2 by resveratrol along with its direct antioxidant effect to ameliorate the oxidative damage and preserve mitochondrial function.
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Affiliation(s)
- V Kesherwani
- Division of Neurosurgery, Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68198-7690, USA
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Ng WP, Fehlings MG, Cuddy B, Dickman C, Fazl M, Green B, Hitchon P, Northrup B, Sonntag V, Wagner F, Tator CH. Surgical treatment for acute spinal cord injury study pilot study #2: evaluation of protocol for decompressive surgery within 8 hours of injury. Neurosurg Focus 2012; 6:e3. [PMID: 17031916 DOI: 10.3171/foc.1999.6.1.4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Acute spinal cord injury (SCI) is a major public health problem for which there is still only limited treatment available. The National Acute Spinal Cord Injury Study-2 (NASCIS-2) and -3 clinical trials demonstrated that the use of acute pharmacotherapy with methylprednisolone can attenuate the secondary injury cascade if administered within 8 hours of acute SCI. However, no trial has been performed to examine whether acute surgical decompressive procedures within this critical 8-hour time window can improve patients' neurological outcome. The purpose of the current prospective Surgical Treatment for Acute Spinal Cord Injury Study (STASCIS) pilot study was to determine the feasibility of obtaining a radiological diagnosis of spinal canal compromise of 25% or more and to perform spinal cord (C3-T1) decompressive procedures by 8 hours postinjury. One of the following three decompressive methods was used: 1) traction alone; 2) traction and surgery; or 3) surgery alone. Twenty-six patients from eight North American centers were entered into the study between 1996 and 1997. Significant difficulties were encountered in many centers in performing immediate magnetic resonance imaging examination in patients with acute SCI. Fewer than 10% of acute cervical SCI patients could be enrolled into this protocol mainly because the combination of the required time for rescue, resuscitation, transport, imaging study, and surgical preparation exceeded the 8-hour injury-to-decompressive surgery window. Eleven patients underwent decompressive procedures initially by being placed in traction at a mean time of 10.9 hours postinjury. Those patients not undergoing this procedure underwent decompressive surgery at a mean time of 40.1 hours. However, the surgical decompressive procedure was completed within 12 hours in seven patients. As a result of these findings, several major changes have been made to the STASCIS protocol for early decompressive therapy.
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Affiliation(s)
- W P Ng
- Division of Neurosurgery, The University of Toronto, The Toronto Hospital, Canada; and Members of the STASCIS Surgical Decompression Study Group
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Borgens RB, Liu-Snyder P. Understanding secondary injury. QUARTERLY REVIEW OF BIOLOGY 2012; 87:89-127. [PMID: 22696939 DOI: 10.1086/665457] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Secondary injury is a term applied to the destructive and self-propagating biological changes in cells and tissues that lead to their dysfunction or death over hours to weeks after the initial insult (the "primary injury"). In most contexts, the initial injury is usually mechanical. The more destructive phase of secondary injury is, however, more responsible for cell death and functional deficits. This subject is described and reviewed differently in the literature. To biomedical researchers, systemic and tissue-level changes such as hemorrhage, edema, and ischemia usually define this subject. To cell and molecular biologists, "secondary injury" refers to a series of predominately molecular events and an increasingly restricted set of aberrant biochemical pathways and products. These biochemical and ionic changes are seen to lead to death of the initially compromised cells and "healthy" cells nearby through necrosis or apoptosis. This latter process is called "bystander damage." These viewpoints have largely dominated the recent literature, especially in studies of the central nervous system (CNS), often without attempts to place the molecular events in the context of progressive systemic and tissue-level changes. Here we provide a more comprehensive and inclusive discussion of this topic.
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Affiliation(s)
- Richard Ben Borgens
- Center for Paralysis Research, School of Veterinary Medicine, Department of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
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Kesherwani V, Agrawal SK. Regulation of inositol 1,4,5-triphosphate receptor, type 1 (IP3R1) in hypoxic/reperfusion injury of white matter. Neurol Res 2012; 34:504-11. [PMID: 22643045 DOI: 10.1179/1743132812y.0000000038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE Calcium overloading is responsible for initiating the cell death in neuronal tissue after hypoxic injury. Inositol 1,4,5-triphosphate receptors (IP3Rs) is an important calcium channel which regulates cellular calcium homeostasis. IP3R1 is widely expressed in brain and spinal tissue. In the present study, we have studied the regulation of IP3R1 in hypoxic/reperfusion injury of spinal cord dorsal column in vitro. METHODS Dorsal columns were isolated from the spinal cord of adult rats and injury was induced by exposing to hypoxic condition for 1 hour. After injury, reperfusion was carried out for 0, 2, 4, and 8 hours. Tissues were collected and processed for western blotting, immunohistochemistry and real-time PCR. RESULTS In the present study, we have found increased expression of IP3R1 after hypoxic/reperfusion injury of spinal cord dorsal column in vitro. Maximum expression of IP3R1 has been seen at 4 hours after hypoxia. Double immunofluorescence studies show the localization of IP3R1 in axons and astrocytes. Further identifying the signaling pathway involved in the regulation, we found Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-62 and c-Jun N-terminal kinase (JNK) inhibitor SP600125 reduced the expression of IP3R1 suggesting the role of CaMKII and JNK in the regulation of IP3R1 expression. We did not find role of ERK and p38 in the regulation IP3R1 expression in hypoxic/reperfusion injury of dorsal column in vitro. DISCUSSION The result presented in this study showed that IP3R1 expression is increased in hypoxic/reperfusion injury of spinal cord white matter and it is regulated by the CaMKII-JNK pathway.
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Affiliation(s)
- Varun Kesherwani
- Division of Neurosurgery, Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68198-6250, USA
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Jang JW, Lee JK, Kim SH. Activation of matrix metalloproteinases-9 after photothrombotic spinal cord injury model in rats. J Korean Neurosurg Soc 2011; 50:288-92. [PMID: 22200008 DOI: 10.3340/jkns.2011.50.4.288] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/02/2011] [Accepted: 10/17/2011] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9 have been known to play an important role in secondary inflammatory reaction after spinal cord injury (SCI). The aim of this study was to investigate the expression and activity of MMP-2 and MMP-9 and to determine their relationship with disruption of endothelial blood-barrier after photochemically induced SCI in rats. METHODS Female Sprague-Dawley rats, weighing between 250 and 300 g (aged 8 weeks) received focal spinal cord ischemia by photothrombosis using Rose Bengal. Expressions and activities of MMP-2 and MMP-9 were assessed by Western blot and gelatin zymography at various times from 6 h to 7 days. Endothelial blood-barrier integrity was assessed indirectly using spinal cord water content. RESULTS Zymography and Western blot analysis demonstrated rapid up-regulation of MMP-9 protein levels in spinal cord after ischemic onset. Expressions and activities of MMP-9 showed a significant increased at 6 h after the photothrombotic ischemic event, and reached a maximum level at 24 h after the insult. By contrast, activated MMP-2 was not detected at any time point in either the experimental or the control groups. When compared with the control group, a significant increase in spinal cord water content was detected in rats at 24 h after photothrombotic SCI. CONCLUSION Early up-regulation of MMP-9 might be correlated with increased water content in the spinal cord at 24 h after SCI in rats. Results of this study suggest that MMP-9 is the key factor involved in disruption of the endothelial blood-barrier of the spinal cord and subsequent secondary damage after photothrombotic SCI in rats.
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Affiliation(s)
- Jae-Won Jang
- Department of Neurosurgery, Chonnam National University Medical School & Research Institute of Medical Sciences, Gwangju, Korea
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Wells J, Kilburn MR, Shaw JA, Bartlett CA, Harvey AR, Dunlop SA, Fitzgerald M. Early in vivo changes in calcium ions, oxidative stress markers, and ion channel immunoreactivity following partial injury to the optic nerve. J Neurosci Res 2011; 90:606-18. [DOI: 10.1002/jnr.22784] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 08/12/2011] [Indexed: 01/19/2023]
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Lepore AC, O'Donnell J, Kim AS, Yang EJ, Tuteja A, Haidet-Phillips A, O'Banion CP, Maragakis NJ. Reduction in expression of the astrocyte glutamate transporter, GLT1, worsens functional and histological outcomes following traumatic spinal cord injury. Glia 2011; 59:1996-2005. [PMID: 21882244 DOI: 10.1002/glia.21241] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 08/04/2011] [Indexed: 12/23/2022]
Abstract
The astrocyte glutamate transporter, GLT1, is responsible for the vast majority of glutamate uptake in the adult central nervous system (CNS), thereby regulating extracellular glutamate homeostasis and preventing excitotoxicity. Glutamate dysregulation plays a central role in outcome following traumatic spinal cord injury (SCI). To determine the role of GLT1 in secondary cell loss following SCI, mice heterozygous for the GLT1 astrocyte glutamate transporter (GLT1+/-) and wild-type mice received thoracic crush SCI. Compared with wild-type controls, GLT1+/- mice had an attenuated recovery in hindlimb motor function, increased lesion size, and decreased tissue sparing. GLT1+/- mice showed a decrease in intraspinal GLT1 protein and functional glutamate uptake compared with wild-type mice, accompanied by increased apoptosis and neuronal loss following crush injury. These results suggest that astrocyte GLT1 plays a role in limiting secondary cell death following SCI, and also show that compromise of key astrocyte functions has significant effects on outcome following traumatic CNS injury. These findings also suggest that increasing intraspinal GLT1 expression may represent a therapeutically relevant target for SCI treatment.
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Affiliation(s)
- Angelo C Lepore
- Department of Neuroscience, Thomas Jefferson University Medical College, 900 Walnut St., Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania, USA
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Mortazavi MM, Verma K, Deep A, Esfahani FB, Pritchard PR, Tubbs RS, Theodore N. Chemical priming for spinal cord injury: a review of the literature. Part I-factors involved. Childs Nerv Syst 2011; 27:1297-306. [PMID: 21170536 DOI: 10.1007/s00381-010-1364-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 12/07/2010] [Indexed: 12/29/2022]
Abstract
INTRODUCTION There are significant differences between the propensity of neural regeneration between the central and peripheral nervous systems. MATERIALS AND METHODS Following a review of the literature, we describe the role of growth factors, guiding factors, and neurite outgrowth inhibitors in the physiology and development of the nervous system as well as the pathophysiology of the spinal cord. We also detail their therapeutic role as well as those of other chemical substances that have recently been found to modify regrowth following cord injury. CONCLUSIONS Multiple factors appear to have promising futures for the possibility of improving spinal cord injury following injury.
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Affiliation(s)
- Martin M Mortazavi
- Department of Neurosurgery, Barrow Neurological Institute, Phoenix, AR, USA
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Kesherwani V, Agrawal SK. Upregulation of RyR2 in hypoxic/reperfusion injury. J Neurotrauma 2011; 29:1255-65. [PMID: 21612318 DOI: 10.1089/neu.2011.1780] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Calcium influx into cells is responsible for initiating the cell death in neuronal tissue after hypoxic injury. Changes in intracellular calcium with subsequent increased expression of ryanodine receptor 2 (RyR2) are hypothesized to cause cell death after hypoxic injury. In the present study we have examined the time-dependent changes of RyR2 expression in hypoxic/reperfusion injury of spinal cord dorsal column. In this study we used western blotting, real time PCR (RT-PCR) and immunohistochemistry to examine changes in protein and gene expression of RyR2 after spinal cord injury (SCI) in the rat. Quantitative immunoblotting showed increase in the expression of RyR2 at 4 h during hypoxic/reperfusion injury of dorsal column. Moreover, RT-PCR showed 36-fold increases in mRNA of RyR2 after 4 h of hypoxic injury of white matter. By double immunofluorescence staining, RyR2 was localized on axons and astrocytes in the white matter of the spinal cord. After treatment with KN-62; (inhibitor of CaMKII) and SP600125 (inhibitor of JNK), there is a significant reduction in the expression of RyR2, indicating the role of these molecules in RyR2 regulation. Further removal of extracellular calcium does not have significant effect on RyR2 expression and phosphorylation of CaMKII, which was further confirmed by treatment with intracellular Ca(++) chelator BAPTA-AM. Finally, bioassay with quantitative analysis showed that treatment with inhibitor significantly reduced the cellular oxidative stress suggesting RyR2 is responsible for increased cellular oxidative load. In summary, we provide evidence that RyR2 gene and protein expression in astrocyte and axons is markedly increased after hypoxic injury. Further CaMKII/JNK pathway upregulates RyR2 expression after hypoxic injury. Therefore we propose that inhibitors of CaMKII/JNK pathway would reduce the cellular oxidative load and thereby have a neuroprotective role.
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Affiliation(s)
- Varun Kesherwani
- Section of Neurosurgery, Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska 68198-6250, USA
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Lin MS, Sun YY, Chiu WT, Hung CC, Chang CY, Shie FS, Tsai SH, Lin JW, Hung KS, Lee YH. Curcumin Attenuates the Expression and Secretion of RANTES after Spinal Cord Injury In Vivo and Lipopolysaccharide-Induced Astrocyte Reactivation In Vitro. J Neurotrauma 2011; 28:1259-69. [DOI: 10.1089/neu.2011.1768] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Muh-Shi Lin
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Surgery, School of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Neurosurgery, Taipei City Hospital, Zhong Xiao Branch, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan
- Division of Neurosurgery, Department of Surgery, Taipei County Hospital, New Taipei City, Taiwan
| | - Yu-Yo Sun
- Division of Cell Physiology and Neuroscience, Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
| | - Wen-Ta Chiu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan
- Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University- Shuang Ho Hospital, New Taipei City, Taiwan
| | - Chia-Chi Hung
- Division of Cell Physiology and Neuroscience, Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
| | - Chiu-Yun Chang
- Division of Cell Physiology and Neuroscience, Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
- Department of Anatomy, Taipei Medical University, Taipei, Taiwan
| | - Feng-Shiun Shie
- Division of Mental Health and Addiction Medicine, National Health Research Institute, Miao-Li County, Taiwan
| | - Shin-Han Tsai
- Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University- Shuang Ho Hospital, New Taipei City, Taiwan
| | - Jia-Wei Lin
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University- Shuang Ho Hospital, New Taipei City, Taiwan
| | - Kuo-Sheng Hung
- Department of Neurosurgery, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan
- Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan
| | - Yi-Hsuan Lee
- Division of Cell Physiology and Neuroscience, Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
- Department and Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
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Lee KH, Kim UJ, Park YG, Won R, Lee H, Lee BH. Optical Imaging of Somatosensory Evoked Potentials in the Rat Cerebral Cortex after Spinal Cord Injury. J Neurotrauma 2011; 28:797-807. [DOI: 10.1089/neu.2010.1492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Kyung Hee Lee
- Department of Dental Hygiene, Division of Health Science, Dongseo University, Busan, Korea
| | - Un Jeng Kim
- Department of Physiology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Yong Gou Park
- Department of Neurosurgery, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Ran Won
- Department of Biomedical Laboratory Science, Division of Health Science, Dongseo University, Busan, Korea
| | - Hyejung Lee
- Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul, Korea
| | - Bae Hwan Lee
- Department of Physiology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
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Lepore AC, O'Donnell J, Bonner JF, Paul C, Miller ME, Rauck B, Kushner RA, Rothstein JD, Fischer I, Maragakis NJ. Spatial and temporal changes in promoter activity of the astrocyte glutamate transporter GLT1 following traumatic spinal cord injury. J Neurosci Res 2011; 89:1001-17. [PMID: 21488085 DOI: 10.1002/jnr.22624] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/20/2010] [Accepted: 01/19/2011] [Indexed: 12/21/2022]
Abstract
After traumatic spinal cord injury (SCI), there is an opportunity for preserving function by attenuating secondary cell loss. Astrocytes play crucial roles in the adult CNS and are responsible for the vast majority of glutamate buffering, potentially preventing excitotoxic loss of neurons and oligodendrocytes. We examined spatial and temporal changes in gene expression of the major astrocyte glutamate transporter GLT1 following moderate thoracic contusion SCI using transgenic BAC-GLT1-eGFP promoter reporter mice. In dorsal column white matter, total intensity of GLT1-eGFP expression per region was significantly reduced following SCI at both lesion epicenter and at rostral and caudal areas where no tissue loss occurred. This regional decrease in GLT1 expression was due to significant loss of GLT1-eGFP(+) cells, partially accounted for by apoptosis of eGFP(+) /GFAP(+) astrocytes in both white and gray matter. There were also decreased numbers of GLT1-eGFP-expressing cells in multiple gray matter regions following injury; nevertheless, there was sustained or even increased regional GLT1-eGFP expression in gray matter as a result of up-regulation in astrocytes that continued to express GLT1-eGFP. Although there were increased numbers of GFAP(+) cells both at the lesion site and in surrounding intact spinal cord following SCI, the majority of proliferating Ki67(+) /GFAP(+) astrocytes did not express GLT1-eGFP. These findings demonstrate that spatial and temporal alterations in GLT1 expression observed after SCI result from both astrocyte death and gene expression changes in surviving astrocytes. Results also suggest that following SCI a significant portion of astrocytes lacks GLT1 expression, possibly compromising the important role of astrocytes in glutamate homeostasis.
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Affiliation(s)
- Angelo C Lepore
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Erschbamer M, Oberg J, Westman E, Sitnikov R, Olson L, Spenger C. 1H-MRS in spinal cord injury: acute and chronic metabolite alterations in rat brain and lumbar spinal cord. Eur J Neurosci 2011; 33:678-88. [PMID: 21251091 PMCID: PMC3072523 DOI: 10.1111/j.1460-9568.2010.07562.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A variety of tests of sensorimotor function are used to characterize outcome after experimental spinal cord injury (SCI). These tests typically do not provide information about chemical and metabolic processes in the injured CNS. Here, we used (1) H-magnetic resonance spectroscopy (MRS) to monitor long-term and short-term chemical changes in the CNS in vivo following SCI. The investigated areas were cortex, thalamus/striatum and the spinal cord distal to injury. In cortex, glutamate (Glu) decreased 1 day after SCI and slowly returned towards normal levels. The combined glutamine (Gln) and Glu signal was similarly decreased in cortex, but increased in the distal spinal cord, suggesting opposite changes of the Glu/Gln metabolites in cortex and distal spinal cord. In lumbar spinal cord, a marked increase of myo-inositol was found 3 days, 14 days and 4 months after SCI. Changes in metabolite concentrations in the spinal cord were also found for choline and N-acetylaspartate. No significant changes in metabolite concentrations were found in thalamus/striatum. Multivariate data analysis allowed separation between rats with SCI and controls for spectra acquired in cortex and spinal cord, but not in thalamus/striatum. Our findings suggest MRS could become a helpful tool to monitor spatial and temporal alterations of metabolic conditions in vivo in the brain and spinal cord after SCI. We provide evidence for dynamic temporal changes at both ends of the neuraxis, cortex cerebri and distal spinal cord, while deep brain areas appear less affected.
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Affiliation(s)
- Matthias Erschbamer
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77 Stockholm, Sweden
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Velumian AA, Wan Y, Samoilova M, Fehlings MG. Contribution of fast and slow conducting myelinated axons to single-peak compound action potentials in rat spinal cord white matter preparations. J Neurophysiol 2010; 105:929-41. [PMID: 21148097 DOI: 10.1152/jn.00435.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Unlike recordings derived from optic nerve or corpus callosum, compound action potentials (CAPs) recorded from rodent spinal cord white matter (WM) have a characteristic single-peak shape despite the heterogeneity of axonal populations. Using a double sucrose gap technique, we analyzed the CAPs recorded from dorsal, lateral, and ventral WM from mature rat spinal cord. The CAP decay was significantly prolonged with increasing stimulus intensities suggesting a recruitment of higher threshold, slower conducting axons. At 3.5 mm conduction distance, a hidden higher threshold, slower conducting component responsible for prolongation of CAP decay was uncovered in 22 of 25 of dorsal WM strips by analyzing the stimulus-response relationships and a normalization-subtraction procedure. This component had a peak conduction velocity (CV) of 5.0 ± 0.2 (SE) m/s as compared with 9.3 ± 0.5 m/s for the lower threshold peak (P < 0.0001). Oxygen-glucose deprivation (OGD), along with its known effects on CAP amplitude, significantly (P < 0.015) shortened the CAP decay. The hidden higher threshold, slower conducting component showed greater sensitivity to OGD compared with the lower threshold, faster conducting component, suggesting a differential sensitivity of axonal populations of spinal cord WM. At longer conduction distances and lower temperatures (9.8 mm, 22-24°C), the slower peak could be directly visualized in CAPs at higher stimulation intensities. A detailed analysis of single-peak CAPs to identify their fast and slow conducting components may be of particular importance for studies of axonal physiology and pathophysiology in small animals where the conduction distance is not sufficiently long to separate the CAP peaks.
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Affiliation(s)
- Alexander A Velumian
- Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, ON M5T 2S8, Canada
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Abematsu M, Tsujimura K, Yamano M, Saito M, Kohno K, Kohyama J, Namihira M, Komiya S, Nakashima K. Neurons derived from transplanted neural stem cells restore disrupted neuronal circuitry in a mouse model of spinal cord injury. J Clin Invest 2010; 120:3255-66. [PMID: 20714104 DOI: 10.1172/jci42957] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 07/07/2010] [Indexed: 01/05/2023] Open
Abstract
The body's capacity to restore damaged neural networks in the injured CNS is severely limited. Although various treatment regimens can partially alleviate spinal cord injury (SCI), the mechanisms responsible for symptomatic improvement remain elusive. Here, using a mouse model of SCI, we have shown that transplantation of neural stem cells (NSCs) together with administration of valproic acid (VPA), a known antiepileptic and histone deacetylase inhibitor, dramatically enhanced the restoration of hind limb function. VPA treatment promoted the differentiation of transplanted NSCs into neurons rather than glial cells. Transsynaptic anterograde corticospinal tract tracing revealed that transplant-derived neurons reconstructed broken neuronal circuits, and electron microscopic analysis revealed that the transplant-derived neurons both received and sent synaptic connections to endogenous neurons. Ablation of the transplanted cells abolished the recovery of hind limb motor function, confirming that NSC transplantation directly contributed to restored motor function. These findings raise the possibility that epigenetic status in transplanted NSCs can be manipulated to provide effective treatment for SCI.
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Affiliation(s)
- Masahiko Abematsu
- Laboratory of Molecular Neuroscience, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
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Hu R, Zhou J, Luo C, Lin J, Wang X, Li X, Bian X, Li Y, Wan Q, Yu Y, Feng H. Glial scar and neuroregeneration: histological, functional, and magnetic resonance imaging analysis in chronic spinal cord injury. J Neurosurg Spine 2010; 13:169-80. [DOI: 10.3171/2010.3.spine09190] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Object
A glial scar is thought to be responsible for halting neuroregeneration following spinal cord injury (SCI). However, little quantitative evidence has been provided to show the relationship of a glial scar and axonal regrowth after injury.
Methods
In this study performed in rats and dogs, a traumatic SCI model was made using a weight-drop injury device, and tissue sections were stained with H & E for immunohistochemical analysis. The function and behavior of model animals were tested using electrophysiological recording and the Basso-Beattie-Bresnahan Locomotor Rating Scale, respectively. The cavity in the spinal cord after SCI in dogs was observed using MR imaging.
Results
The morphological results showed that the formation of an astroglial scar was defined at 4 weeks after SCI. While regenerative axons reached the vicinity of the lesion site, the glial scar blocked the extension of regrown axons. In agreement with these findings, the electrophysiological, behavioral, and in vivo MR imaging tests showed that functional recovery reached a plateau at 4 weeks after SCI. The thickness of the glial scars in the injured rat spinal cords was also measured. The mean thickness of the glial scar rostral and caudal to the lesion cavity was 107.00 ± 20.12 μm; laterally it was 69.92 ± 15.12 μm.
Conclusions
These results provide comprehensive evidence indicating that the formation of a glial scar inhibits axonal regeneration at 4 weeks after SCI. This study reveals a critical time window of postinjury recovery and a detailed spatial orientation of glial scar, which would provide an important basis for the development of therapeutic strategy for glial scar ablation.
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Affiliation(s)
- Rong Hu
- 1Department of Neurosurgery and
| | | | | | | | | | - Xiaoguang Li
- 2Beijing Center for Neural Regeneration and Repairing, Capital University of Medical Sciences, Beijing
| | - Xiuwu Bian
- 3Institute of Pathology, Southwest Hospital, Third Military Medical University, Chongqing
| | - Yunqing Li
- 4Department of Anatomy, Faculty of Basic Medicine, Fourth Military Medical University, Xi'an, China; and
| | - Qi Wan
- 5Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Yanbing Yu
- 6Beijing Sino-Japan Friendship Hospital, Beijing
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Beattie MS, Ferguson AR, Bresnahan JC. AMPA-receptor trafficking and injury-induced cell death. Eur J Neurosci 2010; 32:290-7. [PMID: 20646045 DOI: 10.1111/j.1460-9568.2010.07343.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
AMPA receptors (AMPARs) are critical for synaptic plasticity, and are subject to alterations based on subunit composition and receptor trafficking to and from the plasma membrane. One of the most potent regulators of AMPAR trafficking is the pro-inflammatory cytokine tumor necrosis factor (TNF)α, which is involved in physiological regulation of synaptic strength (Beattie et al., (2002) Science, 295, 2282-2285; Stellwagen and Malenka, (2006) Nature, 440, 1054-1059) and is also present at high concentrations after CNS injury. Here, we review evidence that TNF can rapidly alter the surface expression of AMPARs so that the proportion of Ca(++) -permeable receptors is increased and that this increase, in combination with increased levels of extracellular glutamate after injury, plays an important role in enhancing excitotoxic cell death after CNS injury. Thus, the pathophysiological hijacking of a critical regulator of synaptic plasticity and homeostasis by the secondary injury cascade may represent a new therapeutic target for neuroprotection.
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Affiliation(s)
- Michael S Beattie
- Brain and Spinal Injury Center, Department of Neurological Surgery, University of California, San Francisco, Bldg. 1, Rm 101, San Francisco, CA 94110, USA.
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Nagamoto-Combs K, Morecraft RJ, Darling WG, Combs CK. Long-term gliosis and molecular changes in the cervical spinal cord of the rhesus monkey after traumatic brain injury. J Neurotrauma 2010; 27:565-85. [PMID: 20030560 DOI: 10.1089/neu.2009.0966] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recovery of fine motor skills after traumatic brain injury (TBI) is variable, with some patients showing progressive improvements over time while others show poor recovery. We therefore studied possible cellular mechanisms accompanying the recovery process in a non-human primate model system, in which the lateral frontal motor cortex areas controlling the preferred upper limb were unilaterally lesioned, and the animals eventually regained fine hand motor function. Immunohistochemical staining of the cervical spinal cord, the site of compensatory sprouting and degeneration of corticospinal axons, showed profound increases in immunoreactivities for major histocompatibility complex class II molecule (MHC-II) and extracellular signal-regulated kinases (ERK1/2) up to 12 months post lesion, particularly within the lateral corticospinal tract (LCST). Double immunostaining demonstrated that phosphorylated ERK1/2 colocalized within the MCH-II + microglia, suggesting a trophic role of long-term microglia activation after TBI at the site of compensatory sprouting. Active sprouting was observed in the LCST as well as in the spinal gray matter of the lesioned animals, as illustrated by increases in growth associated protein 43. Upregulation of Nogo receptor and glutamate transporter expression was also observed in this region after TBI, suggesting possible mechanisms for controlling aberrant sprouting and/or synaptic formation en route and interstitial glutamate concentration changes at the site of axon degeneration, respectively. Taken together, these changes in the non-human primate spinal cord support a long-term trophic/tropic role for reactive microglia, in particular, during functional and structural recovery after TBI.
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Affiliation(s)
- Kumi Nagamoto-Combs
- Department of Anatomy and Cell Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, USA
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Springer JE, Rao RR, Lim HR, Cho SI, Moon GJ, Lee HY, Park EJ, Noh JS, Gwag BJ. The functional and neuroprotective actions of Neu2000, a dual-acting pharmacological agent, in the treatment of acute spinal cord injury. J Neurotrauma 2010; 27:139-49. [PMID: 19772458 DOI: 10.1089/neu.2009.0952] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The goal of the present study was to examine the neuroprotective and functional significance of targeting both N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity and oxidative stress using a dual-acting compound, Neu2000, in rat model of moderate spinal cord injury (SCI). An initial set of experiments was conducted in uninjured rats to study the pharmacokinetic profile of Neu2000 following intraperitoneal and intravenous administration. A second experiment measured free radical production in mitochondria isolated from sham or injured spinal cords of animals receiving vehicle or Neu2000 treatment. A third set of animals was divided into three treatment groups consisting of vehicle treatment, a single dose of Neu2000 (50 mg/kg) administered at 10 min following injury, or a repeated treatment paradigm consisting of a single bolus of Neu2000 at 10 min following injury (50 mg/kg) plus a maintenance dose (25 mg/kg) administered every 24 h for an additional 6 days. Animals were tested once a week for a period of 6 weeks for evidence of locomotor recovery in an open field and kinematic analysis of fine motor control using the DigiGait Image Analysis System. At the end of the testing period, spinal cord reconstruction was performed to obtain nonbiased stereological measures of tissue sparing. The results of this study demonstrate that Neu2000 treatment significantly reduced the production of mitochondrial free radicals and improved locomotor outcomes that were associated with a significant increase in the volume of spared spinal cord tissue.
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Affiliation(s)
- Joe E Springer
- Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, Kentucky 40536-0509, USA.
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46
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The AMPA receptor as a therapeutic target: current perspectives and emerging possibilities. Future Med Chem 2010; 2:877-91. [DOI: 10.4155/fmc.10.27] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) is a subtype of the ionotropic glutamate receptors that plays a prominent role in neurotransmission and is widespread throughout the CNS. Because of this, its malfunction can result in a multitude of nervous system diseases. This review looks at compounds that are able to modulate AMPAR function by binding to one of several sites on the receptor that either downregulate its function (competitive, noncompetitive and uncompetitive antagonists) or upregulate its function (positive modulators). It will also give an account of the various diseases that have implicated AMPAR dysfunction and how specific types of AMPAR modulator may be beneficial in their treatment. The AMPAR remains an unexploited but important therapeutic target.
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Mechanisms of axonal injury: internodal nanocomplexes and calcium deregulation. Trends Mol Med 2010; 16:160-70. [PMID: 20207196 DOI: 10.1016/j.molmed.2010.02.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 02/01/2010] [Accepted: 02/03/2010] [Indexed: 12/14/2022]
Abstract
Axonal degeneration causes morbidity in many neurological conditions including stroke, neurotrauma and multiple sclerosis. The limited ability of central nervous system (CNS) neurons to regenerate, combined with the observation that axonal damage causes clinical disability, has spurred efforts to investigate the mechanisms of axonal degeneration. Ca influx from outside the axon is a key mediator of injury. More recently, substantial pools of intra-axonal Ca sequestered in the 'axoplasmic reticulum' have been reported. These Ca stores are under the control of multimolecular 'nanocomplexes' located along the internodes under the myelin. The overactivation of these complexes during disease can lead to a lethal release of Ca from intra-axonal stores. Rich receptor pharmacology offers tantalizing therapeutic options targeting these nanocomplexes in the many diseases where axonal degeneration is prominent.
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Hazell AS, Sheedy D, Oanea R, Aghourian M, Sun S, Jung JY, Wang D, Wang C. Loss of astrocytic glutamate transporters in Wernicke encephalopathy. Glia 2010; 58:148-56. [PMID: 19565658 PMCID: PMC3388119 DOI: 10.1002/glia.20908] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Wernicke encephalopathy (WE), a neurological disorder caused by thiamine deficiency (TD), is characterized by structural damage in brain regions that include the thalamus and cerebral cortex. The basis for these lesions is unclear, but may involve a disturbance of glutamatergic neurotransmission. We have therefore investigated levels of the astrocytic glutamate transporters EAAT1 and EAAT2 in order to evaluate their role in the pathophysiology of this disorder. Histological assessment of the frontal cortex revealed a significant loss of neurons in neuropathologically confirmed cases of WE compared with age-matched controls, concomitant with decreases in alpha-internexin and synaptophysin protein content of 67 and 52% by immunoblotting. EAAT2 levels were diminished by 71% in WE, with levels of EAAT1 also reduced by 62%. Loss of both transporter sites was confirmed by immunohistochemical methods. Development of TD in rats caused a profound loss of EAAT1 and EAAT2 in the thalamus accompanied by decreases in other astrocyte-specific proteins. Treatment of TD rats with N-acetylcysteine prevented the downregulation of EAAT2 in the medial thalamus, and ameliorated the loss of several other astrocyte proteins, concomitant with increased neuronal survival. Our results suggest that (1) loss of EAAT1 and EAAT2 glutamate transporters is associated with structural damage to the frontal cortex in patients with WE, (2) oxidative stress plays an important role in this process, and (3) TD has a profound effect on the functional integrity of astrocytes. Based on these findings, we recommend that early treatment using a combination of thiamine AND antioxidant approaches should be an important consideration in cases of WE.
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Affiliation(s)
- Alan S Hazell
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada.
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Modular double sucrose gap apparatus for improved recording of compound action potentials from rat and mouse spinal cord white matter preparations. J Neurosci Methods 2009; 187:33-40. [PMID: 20034518 DOI: 10.1016/j.jneumeth.2009.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 12/11/2009] [Accepted: 12/11/2009] [Indexed: 11/21/2022]
Abstract
Compound action potential (CAP) recording is a powerful tool for studying the conduction properties and pharmacology of axons in multi-axonal preparations. The sucrose gap technique improves CAP recording by replacing the extracellular solution between the recording electrodes with a non-conductive sucrose solution to minimize extracellular shunting. The double sucrose gap (DSG), conferring similar advantages at the stimulation site, has been extensively used on guinea pig spinal cord white matter (WM) in vitro. Establishing the DSG methodology for WM preparations from smaller animals such as rats and mice is appealing due to their extensive use in basic and translationally oriented research. Here we describe a versatile modular DSG apparatus with rubber membrane separation of the compartments, suitable for WM strips from rat and mouse spinal cord. The small volumes of compartments (<0.1 ml) and the air-tight design allow perfusion rates of 0.5-1 ml/min with faster refreshment rates compared to commonly used 2-3 ml/min and larger compartments, providing economical usage of expensive pharmacological drugs. Our improved DSG design is particularly efficient for uncovering slower conducting, higher threshold CAP components, as demonstrated by recordings of C-wave (non-myelinated axons) in rat dorsal WM. In myelin-deficient Shiverer mice with genetically dysmyelinated axons, our DSG apparatus recordings revealed a multi-peak C-wave without preceding faster components. The improved stimulation and recording with our DSG apparatus, lowering the range of required stimulus intensities and reducing the artifact interference with recorded CAPs provide for critical technical advantages that allow for more detailed analysis of CAPs in relatively short preparations.
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50
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Pitt D, Gonzales E, Cross AH, Goldberg MP. Dysmyelinated axons in shiverer mice are highly vulnerable to alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated toxicity. Brain Res 2009; 1309:146-54. [PMID: 19896473 DOI: 10.1016/j.brainres.2009.10.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 10/25/2009] [Accepted: 10/27/2009] [Indexed: 01/01/2023]
Abstract
Glutamate excitotoxicity plays a role in white matter injury in many neurological diseases. Oligodendrocytes in particular are highly vulnerable to excitotoxicity, mediated through activation of AMPA/kainate receptors. Myelin may also be injured independently via NMDA (N-methyl-D-aspartic acid) receptors located on peripheral oligodendroglial processes. Central axons are susceptible to glutamate receptor activation in vivo, but it is unclear whether this is mediated directly by activation of receptors expressed on axons, or indirectly through glutamate toxicity of myelin or neighboring glial cells. We examined axonal vulnerability in mice deficient in myelin basic protein (shiverer), also expressing yellow fluorescent protein (YFP) in a subset of axons. YFP fluorescence, EM, and mouse behavior were assessed 24 h after microstereotactical injections of S-AMPA or NMDA into lumbar dorsal columns. S-AMPA injection led to impaired rotarod performance and widespread axonal degeneration and was more pronounced in shiverer mice than controls. In contrast, NMDA injection did not cause axonal injury or behavioral changes in either group. These results indicate that spinal cord axons in vivo are vulnerable to toxicity mediated by AMPA but not NMDA receptors. The presence of compact myelin is not required for excitotoxic axon damage, and its absence may increase vulnerability. Further understanding of AMPA receptor-mediated axonal toxicity may provide new targets for neuroprotective therapy in WM diseases.
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Affiliation(s)
- David Pitt
- Department of Neurology, Division of Neuroimmunology, The Ohio State University, 460 W. 12th Ave., Columbus, OH 43210, USA.
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