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Seksenyan A, Ron-Harel N, Azoulay D, Cahalon L, Cardon M, Rogeri P, Ko MK, Weil M, Bulvik S, Rechavi G, Amariglio N, Konen E, Koronyo-Hamaoui M, Somech R, Schwartz M. Thymic involution, a co-morbidity factor in amyotrophic lateral sclerosis. J Cell Mol Med 2010; 14:2470-82. [PMID: 19650830 PMCID: PMC3823164 DOI: 10.1111/j.1582-4934.2009.00863.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 07/10/2009] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating disease, characterized by extremely rapid loss of motor neurons. Our studies over the last decade have established CD4(+) T cells as important players in central nervous system maintenance and repair. Those results, together with recent findings that CD4(+) T cells play a protective role in mouse models of ALS, led us to the current hypothesis that in ALS, a rapid T-cell malfunction may develop in parallel to the motor neuron dysfunction. Here, we tested this hypothesis by assessing thymic function, which serves as a measure of peripheral T-cell availability, in an animal model of ALS (mSOD1 [superoxide dismutase] mice; G93A) and in human patients. We found a significant reduction in thymic progenitor-cell content, and abnormal thymic histology in 3-4-month-old mSOD1 mice. In ALS patients, we found a decline in thymic output, manifested in the reduction in blood levels of T-cell receptor rearrangement excision circles, a non-invasive measure of thymic function, and demonstrated a restricted T-cell repertoire. The morbidity of the peripheral immune cells was also manifested in the increase of pro-apoptotic BAX/BCXL2 expression ratio in peripheral blood mononuclear cells (PBMCs) of these patients. In addition, gene expression screening in the same PBMCs, revealed in the ALS patients a reduction in key genes known to be associated with T-cell activity, including: CD80, CD86, IFNG and IL18. In light of the reported beneficial role of T cells in animal models of ALS, the present observation of thymic dysfunction, both in human patients and in an animal model, might be a co-pathological factor in ALS, regardless of the disease aetiology. These findings may lead to the development of novel therapeutic approaches directed at overcoming the thymic defect and T-cell deficiency.
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Affiliation(s)
- Akop Seksenyan
- Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA
| | - Noga Ron-Harel
- Department of Neurobiology, the Weizmann Institute of ScienceRehovot, Israel
| | - David Azoulay
- Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA
| | - Liora Cahalon
- Department of Neurobiology, the Weizmann Institute of ScienceRehovot, Israel
| | - Michal Cardon
- Department of Neurobiology, the Weizmann Institute of ScienceRehovot, Israel
| | - Patricia Rogeri
- Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA
| | - Minhee K Ko
- Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA
| | - Miguel Weil
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv UniversityTel Aviv, Israel
| | - Shlomo Bulvik
- Hematology Department, Laniado HospitalNetanya, Israel
| | - Gideon Rechavi
- Cancer Research Center, Sheba Medical Center, Tel Hashomer and Sackler School of MedicineTel Aviv, Israel
| | - Ninette Amariglio
- Cancer Research Center, Sheba Medical Center, Tel Hashomer and Sackler School of MedicineTel Aviv, Israel
| | - Eli Konen
- Department of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer and Sackler School of MedicineTel Aviv, Israel
| | - Maya Koronyo-Hamaoui
- Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA
| | - Raz Somech
- Cancer Research Center, Sheba Medical Center, Tel Hashomer and Sackler School of MedicineTel Aviv, Israel
- Pediatric Immunology Service, Safra Children’s Hospital, Sheba Medical Center, Tel Hashomer and Sackler School of MedicineTel Aviv, Israel
| | - Michal Schwartz
- Maxine-Dunitz Neurosurgical Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA
- Department of Neurobiology, the Weizmann Institute of ScienceRehovot, Israel
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152
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Kim HM, Lee HJ, Lee MY, Kim SU, Kim BG. Organotypic spinal cord slice culture to study neural stem/progenitor cell microenvironment in the injured spinal cord. Exp Neurobiol 2010; 19:106-13. [PMID: 22110349 PMCID: PMC3214779 DOI: 10.5607/en.2010.19.2.106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 09/28/2010] [Indexed: 11/19/2022] Open
Abstract
The molecular microenvironment of the injured spinal cord does not support survival and differentiation of either grafted or endogenous NSCs, restricting the effectiveness of the NSC-based cell replacement strategy. Studying the biology of NSCs in in vivo usually requires a considerable amount of time and cost, and the complexity of the in vivo system makes it difficult to identify individual environmental factors. The present study sought to establish the organotypic spinal cord slice culture that closely mimics the in vivo environment. The cultured spinal cord slices preserved the cytoarchitecture consisting of neurons in the gray matter and interspersed glial cells. The majority of focally applied exogenous NSCs survived up to 4 weeks. Pre-exposure of the cultured slices to a hypoxic chamber markedly reduced the survival of seeded NSCs on the slices. Differentiation into mature neurons was severely limited in this co-culture system. Endogenous neural progenitor cells were marked by BrdU incorporation, and applying an inflammatory cytokine IL-1β significantly increased the extent of endogenous neural progenitors with the oligodendrocytic lineage. The present study shows that the organotypic spinal cord slice culture can be properly utilized to study molecular factors from the post-injury microenvironment affecting NSCs in the injured spinal cord.
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Affiliation(s)
- Hyuk Min Kim
- Brain Disease Research Center, Institute for Medical Sciences, and Department of Neurology, Ajou University School of Medicine, Suwon 442-721, Korea
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153
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Patel CB, Cohen DM, Ahobila-Vajjula P, Sundberg LM, Chacko T, Narayana PA. Effect of VEGF treatment on the blood-spinal cord barrier permeability in experimental spinal cord injury: dynamic contrast-enhanced magnetic resonance imaging. J Neurotrauma 2010; 26:1005-16. [PMID: 19226205 DOI: 10.1089/neu.2008.0860] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Compromised blood-spinal cord barrier (BSCB) is a factor in the outcome following traumatic spinal cord injury (SCI). Vascular endothelial growth factor (VEGF) is a potent stimulator of angiogenesis and vascular permeability. The role of VEGF in SCI is controversial. Relatively little is known about the spatial and temporal changes in the BSCB permeability following administration of VEGF in experimental SCI. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) studies were performed to noninvasively follow spatial and temporal changes in the BSCB permeability following acute administration of VEGF in experimental SCI over a post-injury period of 56 days. The DCE-MRI data was analyzed using a two-compartment pharmacokinetic model. Animals were assessed for open field locomotion using the Basso-Beattie-Bresnahan score. These studies demonstrate that the BSCB permeability was greater at all time points in the VEGF-treated animals compared to saline controls, most significantly in the epicenter region of injury. Although a significant temporal reduction in the BSCB permeability was observed in the VEGF-treated animals, BSCB permeability remained elevated even during the chronic phase. VEGF treatment resulted in earlier improvement in locomotor ability during the chronic phase of SCI. This study suggests a beneficial role of acutely administered VEGF in hastening neurobehavioral recovery after SCI.
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Affiliation(s)
- Chirag B Patel
- Department of Diagnostic and Interventional Imaging, University of Texas Medical School at Houston, Houston, Texas 77030, USA
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154
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Simard JM, Woo SK, Norenberg MD, Tosun C, Chen Z, Ivanova S, Tsymbalyuk O, Bryan J, Landsman D, Gerzanich V. Brief suppression of Abcc8 prevents autodestruction of spinal cord after trauma. Sci Transl Med 2010; 2:28ra29. [PMID: 20410530 DOI: 10.1126/scitranslmed.3000522] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Spinal cord injury (SCI) is typically complicated by progressive hemorrhagic necrosis, an autodestructive process of secondary injury characterized by progressive enlargement of a hemorrhagic contusion during the first several hours after trauma. We assessed the role of Abcc8, which encodes sulfonylurea receptor 1 (SUR1), in progressive hemorrhagic necrosis. After SCI, humans and rodents exhibited similar regional and cellular patterns of up-regulation of SUR1 and Abcc8 messenger RNA. Elimination of SUR1 in Abcc8(-/-) mice and in rats given antisense oligodeoxynucleotide against Abcc8 prevented progressive hemorrhagic necrosis, yielded significantly better neurological function, and resulted in lesions that were one-fourth to one-third the size of those in control animals. The beneficial effects of Abcc8 suppression were associated with prevention of oncotic (necrotic) death of capillary endothelial cells. Suppression of Abcc8 with antisense oligodeoxynucleotide after SCI presents an opportunity for reducing the devastating sequelae of SCI.
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Affiliation(s)
- J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, 22 South Greene Street, Suite S12D, Baltimore, MD 21201-1595, USA.
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155
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Mladinic M, Lefèvre C, Del Bel E, Nicholls J, Digby M. Developmental changes of gene expression after spinal cord injury in neonatal opossums. Brain Res 2010; 1363:20-39. [PMID: 20849836 DOI: 10.1016/j.brainres.2010.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 09/07/2010] [Indexed: 01/16/2023]
Abstract
Changes in gene expression have been measured 24h after injury to mammalian spinal cords that can and cannot regenerate. In opossums there is a critical period of development when regeneration stops being possible: at 9 days postnatal cervical spinal cords regenerate, at 12 days they do not. By the use of marsupial cDNA microarrays, we detected 158 genes that respond differentially to injury at the two ages critical for regeneration. For selected candidates additional measurements were made by real-time PCR and sites of their expression were shown by immunostaining. Candidate genes have been classified so as to select those that promote or prevent regeneration. Up-regulated by injury at 8 days and/or down-regulated by injury at 13 days were genes known to promote growth, such as Mitogen-activated protein kinase kinase 1 or transcription factor TCF7L2. By contrast, at 13 days, up-regulation occurred of inhibitory molecules, including annexins, ephrins, and genes related to apoptosis and neurodegenerative diseases. Certain genes such as calmodulin 1 and NOGO, changed expression similarly in animals that could and could not regenerate without any additional changes in response to injury. These findings confirmed and extended changes of gene expression found in earlier screens on 9 and 12 ay preparations without lesions and provide a comprehensive list of genes that serve as a basis for testing how identified molecules, singly or in combination, promote and prevent central nervous system regeneration.
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Affiliation(s)
- Miranda Mladinic
- SISSA, Department of Neurobiology, Via Bonomea 265, 34136 Trieste, Italy.
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156
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Cadotte DW, Singh A, Fehlings MG. The timing of surgical decompression for spinal cord injury. F1000 MEDICINE REPORTS 2010; 2:67. [PMID: 21173861 PMCID: PMC2990468 DOI: 10.3410/m2-67] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Research into the pathophysiological mechanisms of spinal cord injury (SCI) has resulted in a classification scheme of primary and secondary injury. Primary injury refers to the destructive nature of the initial impact and the subsequent shearing, penetrating, and compressive forces that injure the delicate neural tissue. Secondary injury refers to a complex array of pathophysiologial processes – including ischemia, inflammation, excitotoxicity, and oxidative cell damage – that contribute to the ultimate loss of neural tissue. While our understanding of secondary mechanisms improves with continued research, novel treatments for SCI are currently being developed with a foundation rooted in halting deleterious secondary mechanisms. In this article, we will review the current evidence for surgical decompression as a treatment for SCI. Emerging evidence and a growing consensus among surgeons are in support of early surgical intervention to help minimize the secondary damage caused by compression of the spinal cord after trauma.
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Affiliation(s)
- David W Cadotte
- Department of Surgery, Division of Neurosurgery, University of Toronto, and Spinal Program, Toronto Western Hospital, University Health Network McLaughlin Pavilion, 12th Floor, Room 407, 399 Bathurst Street, Toronto, ON, M5T 2S8
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157
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Xu HP, Gou L, Dong HW. Study glial cell heterogeneity influence on axon growth using a new coculture method. J Vis Exp 2010:2111. [PMID: 20834226 PMCID: PMC3157876 DOI: 10.3791/2111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In the central nervous system of all mammals, severed axons after injury are unable to regenerate to their original targets and functional recovery is very poor. The failure of axon regeneration is a combined result of several factors including the hostile glial cell environment, inhibitory myelin related molecules and decreased intrinsic neuron regenerative capacity. Astrocytes are the most predominant glial cell type in central nervous system and play important role in axon functions under physiology and pathology conditions. Contrast to the homologous oligodendrocytes, astrocytes are a heterogeneous cell population composed by different astrocyte subpopulations with diverse morphologies and gene expression. The functional significance of this heterogeneity, such as their influences on axon growth, is largely unknown. To study the glial cell, especially the function of astrocyte heterogeneity in neuron behavior, we established a new method by co-culturing high purified dorsal root ganglia neurons with glial cells obtained from the rat cortex. By this technique, we were able to directly compare neuron adhesion and axon growth on different astrocytes subpopulations under the same condition. In this report, we give the detailed protocol of this method for astrocytes isolation and culture, dorsal root ganglia neurons isolation and purification, and the co-culture of DRG neurons with astrocytes. This method could also be extended to other brain regions to study cellular or regional specific interaction between neurons and glial cells.
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Affiliation(s)
- Han-Peng Xu
- Department of Neurosurgery, Cedars Sinai Medical Center, UCLA, USA.
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158
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Abstract
Retinal ganglion cells are usually not able to regenerate their axons after optic nerve injury or degenerative disorders, resulting in lifelong visual loss. This situation can be partially reversed by activating the intrinsic growth state of retinal ganglion cells, maintaining their viability, and counteracting inhibitory signals in the extracellular environment. Advances during the past few years continue to extend the amount of regeneration that can be achieved in animal models. These findings give hope that clinically meaningful regeneration may become a reality within a few years if regenerating axons can be guided to their appropriate destinations.
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Affiliation(s)
- Larry I Benowitz
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, Department of Surgery, Harvard Medical School, Massachusetts, USA.
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159
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Lundell H, Barthelemy D, Skimminge A, Dyrby TB, Biering-Sørensen F, Nielsen JB. Independent spinal cord atrophy measures correlate to motor and sensory deficits in individuals with spinal cord injury. Spinal Cord 2010; 49:70-5. [PMID: 20697420 DOI: 10.1038/sc.2010.87] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
STUDY DESIGN Cross-sectional descriptive analysis of magnetic resonance imaging (MRI) and clinical outcome. OBJECTIVES The aim of this study was to present anatomically consistent and independent spinal cord atrophy measures based on standard MRI material and analyze their specific relations to sensory and motor outcome in individuals with chronic incomplete spinal cord injury (SCI). SETTING Danish study on human SCI. METHODS We included 19 individuals with chronic incomplete SCI and 16 healthy controls. Participants underwent MRI and a neurological examination including sensory testing for light touch and pinprick, and muscle strength. Antero-posterior width (APW), left-right width (LRW) and cross-sectional spinal cord area (SCA) were extracted from MRI at the spinal level of C2. The angular variation of the spinal cord radius over the full circle was also extracted and compared with the clinical scores. RESULTS The motor score was correlated to LRW and the sensory scores were correlated to APW. The scores correlated also well with decreases in spinal cord radius in oblique angles in coherent and non-overlapping sectors for the sensory and motor qualities respectively. CONCLUSION APW and LRW can be used to assess sensory and motor function independently. The finding is corresponding well with the respective locations of the main sensory and motor pathways.
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Affiliation(s)
- H Lundell
- Department of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark.
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160
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Kuzhandaivel A, Margaryan G, Nistri A, Mladinic M. Extensive glial apoptosis develops early after hypoxic-dysmetabolic insult to the neonatal rat spinal cord in vitro. Neuroscience 2010; 169:325-38. [DOI: 10.1016/j.neuroscience.2010.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 05/03/2010] [Accepted: 05/05/2010] [Indexed: 01/08/2023]
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161
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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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162
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Sharma HS, Zimmermann-Meinzingen S, Johanson CE. Cerebrolysin reduces blood-cerebrospinal fluid barrier permeability change, brain pathology, and functional deficits following traumatic brain injury in the rat. Ann N Y Acad Sci 2010; 1199:125-37. [PMID: 20633118 DOI: 10.1111/j.1749-6632.2009.05329.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Traumatic brain injuries (TBIs) induce profound breakdown of the blood-brain and blood-cerebrospinal fluid barriers (BCSFB), brain pathology/edema, and sensory-motor disturbances. Because neurotrophic factors, such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and glial cell-derived neurotrophic factor (GDNF), are neuroprotective in models of brain and spinal cord injuries, we hypothesized that a combination of neurotrophic factors would enhance neuroprotective efficacy. In the present investigation, we examined the effects of Cerebrolysin, a mixture of different neurotrophic factors (Ebewe Neuro Pharma, Austria) on the brain pathology and functional outcome in a rat model of TBI. TBI was produced under Equithesin (3 mL/kg, i.p.) anesthesia by making a longitudinal incision into the right parietal cerebral cortex. Untreated injured rats developed profound disruption of the blood-brain barrier (BBB) to proteins, edema/cell injury, and marked sensory-motor dysfunctions on rota-rod and grid-walking tests at 5 h TBI. Intracerebroventricular administration of Cerebrolysin (10 or 30 microL) either 5 min or 1 h after TBI significantly reduced leakage of Evans blue and radioiodine tracers across the BBB and BCSFB, and attenuated brain edema formation/neuronal damage in the cortex as well as underlying subcortical regions. Cerebrolysin-treated animals also had improved sensory-motor functions. However, administration of Cerebrolysin 2 h after TBI did not affect these parameters significantly. These observations in TBI demonstrate that early intervention with Cerebrolysin reduces BBB and BCSFB permeability changes, attenuates brain pathology and brain edema, and mitigates functional deficits. Taken together, our observations suggest that Cerebrolysin has potential therapeutic value in TBI.
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Affiliation(s)
- Hari Shanker Sharma
- Laboratory of Cerebrovascular Research, Institute of Surgical Sciences, Department of Anaesthesiology & Intensive Care, University Hospital, Uppsala University, Uppsala, Sweden.
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163
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Jakeman LB, Hoschouer EL, Basso DM. Injured mice at the gym: review, results and considerations for combining chondroitinase and locomotor exercise to enhance recovery after spinal cord injury. Brain Res Bull 2010; 84:317-26. [PMID: 20558254 DOI: 10.1016/j.brainresbull.2010.06.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 06/02/2010] [Accepted: 06/02/2010] [Indexed: 01/08/2023]
Abstract
Exercise provides a number of important benefits after spinal cord injury in clinical studies and animal models. However, the amount of functional improvement in overground locomotion obtained with exercise alone has been limited thus far, for reasons that are still poorly understood. One hypothesis is that the complex network of endogenous extracellular matrix components, including chondroitin sulfate proteoglycans (CSPGs), can inhibit exercise-induced remodeling and limit plasticity of spared circuitry in the adult central nervous system. Recent animal studies have shown that chondroitinase ABC (ChABC) can enhance plasticity in the adult nervous system by cleaving glycosaminoglycan sidechains from CSPGs. In this article we review the current literature on plasticity observed with locomotor training and following degradation of CSPGs with ChABC and then present a rationale for the use of exercise combined with ChABC to promote functional recovery after spinal cord injury. We also present results of a preliminary study that tested the simplest approach for combining these treatments; use of a single intraparenchymal injection of ChABC administered to the lumbar enlargement of mice with voluntary wheel running exercise after a mid-thoracic spinal contusion injury. The results are negative, yet serve to highlight limitations in our understanding of the most effective protocols for combining these approaches. Further work is directed to identify the timing, type, and quantity of exercise and pharmacological interventions that can be used to maximize functional improvements by strengthening appropriate synaptic connections.
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Affiliation(s)
- Lyn B Jakeman
- Department of Physiology and Cell Biology, The Ohio State University Medical Center, Columbus, 43210, USA.
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164
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Nistri A, Taccola G, Mladinic M, Margaryan G, Kuzhandaivel A. Deconstructing locomotor networks with experimental injury to define their membership. Ann N Y Acad Sci 2010; 1198:242-51. [DOI: 10.1111/j.1749-6632.2009.05427.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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165
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Ryge J, Winther O, Wienecke J, Sandelin A, Westerdahl AC, Hultborn H, Kiehn O. Transcriptional regulation of gene expression clusters in motor neurons following spinal cord injury. BMC Genomics 2010; 11:365. [PMID: 20534130 PMCID: PMC2900267 DOI: 10.1186/1471-2164-11-365] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 06/09/2010] [Indexed: 01/09/2023] Open
Abstract
Background Spinal cord injury leads to neurological dysfunctions affecting the motor, sensory as well as the autonomic systems. Increased excitability of motor neurons has been implicated in injury-induced spasticity, where the reappearance of self-sustained plateau potentials in the absence of modulatory inputs from the brain correlates with the development of spasticity. Results Here we examine the dynamic transcriptional response of motor neurons to spinal cord injury as it evolves over time to unravel common gene expression patterns and their underlying regulatory mechanisms. For this we use a rat-tail-model with complete spinal cord transection causing injury-induced spasticity, where gene expression profiles are obtained from labeled motor neurons extracted with laser microdissection 0, 2, 7, 21 and 60 days post injury. Consensus clustering identifies 12 gene clusters with distinct time expression profiles. Analysis of these gene clusters identifies early immunological/inflammatory and late developmental responses as well as a regulation of genes relating to neuron excitability that support the development of motor neuron hyper-excitability and the reappearance of plateau potentials in the late phase of the injury response. Transcription factor motif analysis identifies differentially expressed transcription factors involved in the regulation of each gene cluster, shaping the expression of the identified biological processes and their associated genes underlying the changes in motor neuron excitability. Conclusions This analysis provides important clues to the underlying mechanisms of transcriptional regulation responsible for the increased excitability observed in motor neurons in the late chronic phase of spinal cord injury suggesting alternative targets for treatment of spinal cord injury. Several transcription factors were identified as potential regulators of gene clusters containing elements related to motor neuron hyper-excitability, the manipulation of which potentially could be used to alter the transcriptional response to prevent the motor neurons from entering a state of hyper-excitability.
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Affiliation(s)
- Jesper Ryge
- Mammalian Locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden.
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166
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Mazzone G, Margaryan G, Kuzhandaivel A, Nasrabady S, Mladinic M, Nistri A. Kainate-induced delayed onset of excitotoxicity with functional loss unrelated to the extent of neuronal damage in the in vitro spinal cord. Neuroscience 2010; 168:451-62. [DOI: 10.1016/j.neuroscience.2010.03.055] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 03/19/2010] [Accepted: 03/26/2010] [Indexed: 11/29/2022]
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167
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Siffrin V, Vogt J, Radbruch H, Nitsch R, Zipp F. Multiple sclerosis – candidate mechanisms underlying CNS atrophy. Trends Neurosci 2010; 33:202-10. [PMID: 20153532 DOI: 10.1016/j.tins.2010.01.002] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 12/11/2009] [Accepted: 01/08/2010] [Indexed: 11/30/2022]
Affiliation(s)
- Volker Siffrin
- Department of Neurology, University Medicine Mainz, Johannes Gutenberg University Mainz, Germany
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168
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Abstract
Axonal degeneration is an initial key step in traumatic and neurodegenerative CNS disorders. We established a unique in vivo epifluorescence imaging paradigm to characterize very early events in axonal degeneration in the rat optic nerve. Single retinal ganglion cell axons were visualized by AAV-mediated expression of dsRed and this allowed the quantification of postlesional acute axonal degeneration (AAD). EM analysis revealed severe structural alterations of the cytoskeleton, cytoplasmatic vacuolization, and the appearance of autophagosomes within the first hours after lesion. Inhibition of autophagy resulted in an attenuation of acute axonal degeneration. Furthermore, a rapid increase of intraaxonal calcium levels following crush lesion could be visualized using a calcium-sensitive dye. Application of calcium channel inhibitors prevented crush-induced calcium increase and markedly attenuated axonal degeneration, whereas application of a calcium ionophore aggravated the degenerative phenotype. We finally demonstrate that increased postlesional autophagy is calcium dependent and thus mechanistically link autophagy and intraaxonal calcium levels. Both processes are proposed to be major targets for the manipulation of axonal degeneration in future therapeutic settings.
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169
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Zhang SX, Huang F, Gates M, White J, Holmberg EG. Tail nerve electrical stimulation induces body weight-supported stepping in rats with spinal cord injury. J Neurosci Methods 2010; 187:183-9. [DOI: 10.1016/j.jneumeth.2010.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 01/06/2010] [Accepted: 01/08/2010] [Indexed: 10/20/2022]
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170
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Ronaghi M, Erceg S, Moreno-Manzano V, Stojkovic M. Challenges of stem cell therapy for spinal cord injury: human embryonic stem cells, endogenous neural stem cells, or induced pluripotent stem cells? Stem Cells 2010; 28:93-9. [PMID: 19904738 DOI: 10.1002/stem.253] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spinal cord injury (SCI) causes myelopathy, damage to white matter, and myelinated fiber tracts that carry sensation and motor signals to and from the brain. The gray matter damage causes segmental losses of interneurons and motoneurons and restricts therapeutic options. Recent advances in stem cell biology, neural injury, and repair, and the progress toward development of neuroprotective and regenerative interventions are the basis for increased optimism. This review summarizes the pathophysiological mechanisms following SCI and compares human embryonic, adult neural, and the induced pluripotent stem cell-based therapeutic strategies for SCI.
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Affiliation(s)
- Mohammad Ronaghi
- Cellular Reprogramming Laboratory, Centro de Investigación Príncipe Felipe, Valencia, Spain
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171
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Establishing a model spinal cord injury in the African green monkey for the preclinical evaluation of biodegradable polymer scaffolds seeded with human neural stem cells. J Neurosci Methods 2010; 188:258-69. [PMID: 20219534 DOI: 10.1016/j.jneumeth.2010.02.019] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 02/19/2010] [Accepted: 02/22/2010] [Indexed: 12/11/2022]
Abstract
Given the involvement of post-mitotic neurons, long axonal tracts and incompletely elucidated injury and repair pathways, spinal cord injury (SCI) presents a particular challenge for the creation of preclinical models to robustly evaluate longitudinal changes in neuromotor function in the setting in the presence and absence of intervention. While rodent models exhibit high degrees of spontaneous recovery from SCI injury, animal care concerns preclude complete cord transections in non-human primates and other larger vertebrate models. To overcome such limitations a segmental thoracic (T9-T10) spinal cord hemisection was created and characterized in the African green monkey. Physiological tolerance of the model permitted behavioral analyses for a prolonged period post-injury, extending to predefined study termination points at which histological and immunohistochemical analyses were performed. Four monkeys were evaluated (one receiving no implant at the lesion site, one receiving a poly(lactide-co-glycolide) (PLGA) scaffold, and two receiving PLGA scaffolds seeded with human neural stem cells (hNSC)). All subjects exhibited Brown-Séquard syndrome 2 days post-injury consisting of ipsilateral hindlimb paralysis and contralateral hindlimb hypesthesia with preservation of bowel and bladder function. A 20-point observational behavioral scoring system allowed quantitative characterization of the levels of functional recovery. Histological endpoints including silver degenerative staining and Iba1 immunohistochemistry, for microglial and macrophage activation, were determined to reliably define lesion extent and correlate with neurobehavioral data, and justify invasive telemetered electromyographic and kinematic studies to more definitively address efficacy and mechanism.
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172
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Neuroprotection of locomotor networks after experimental injury to the neonatal rat spinal cord in vitro. Neuroscience 2010; 165:996-1010. [DOI: 10.1016/j.neuroscience.2009.10.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 10/07/2009] [Accepted: 10/29/2009] [Indexed: 02/08/2023]
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A large-scale chemical screen for regulators of the arginase 1 promoter identifies the soy isoflavone daidzeinas a clinically approved small molecule that can promote neuronal protection or regeneration via a cAMP-independent pathway. J Neurosci 2010; 30:739-48. [PMID: 20071539 DOI: 10.1523/jneurosci.5266-09.2010] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
An ideal therapeutic for stroke or spinal cord injury should promote survival and regeneration in the CNS. Arginase 1 (Arg1) has been shown to protect motor neurons from trophic factor deprivation and allow sensory neurons to overcome neurite outgrowth inhibition by myelin proteins. To identify small molecules that capture Arg1's protective and regenerative properties, we screened a hippocampal cell line stably expressing the proximal promoter region of the arginase 1 gene fused to a reporter gene against a library of compounds containing clinically approved drugs. This screen identified daidzein as a transcriptional inducer of Arg1. Both CNS and PNS neurons primed in vitro with daidzein overcame neurite outgrowth inhibition from myelin-associated glycoprotein, which was mirrored by acutely dissociated and cultured sensory neurons primed in vivo by intrathecal or subcutaneous daidzein infusion. Further, daidzein was effective in promoting axonal regeneration in vivo in an optic nerve crush model when given intraocularly without lens damage, or most importantly, when given subcutaneously after injury. Mechanistically, daidzein requires transcription and induction of Arg1 activity for its ability to overcome myelin inhibition. In contrast to canonical Arg1 activators, daidzein increases Arg1 without increasing CREB phosphorylation, suggesting its effects are cAMP-independent. Accordingly, it may circumvent known CNS side effects of some cAMP modulators. Indeed, daidzein appears to be safe as it has been widely consumed in soy products, crosses the blood-brain barrier, and is effective without pretreatment, making it an ideal candidate for development as a therapeutic for spinal cord injury or stroke.
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174
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Baptiste DC, Tighe A, Fehlings MG. Spinal cord injury and neural repair: focus on neuroregenerative approaches for spinal cord injury. Expert Opin Investig Drugs 2010; 18:663-73. [PMID: 19379122 DOI: 10.1517/13543780902897623] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND This review discusses the urgent need for improved therapeutic approaches aimed at restoring function following traumatic spinal cord injury (SCI). The focus of this paper is neuroregenerative approaches for SCI, with a highlighted comparison of recent advances in the field and comparisons to that made by Cethrin (Alseres Pharmaceuticals, Inc.), the leading nerve repair product. OBJECTIVE This review first provides the reader with an understanding of SCI. The market for promising therapeutics that can either intervene in secondary etiological mechanisms or ameliorate symptoms associated with SCI are then discussed. The reader will also learn about Cethrin and its current status in clinical evaluation. METHODS Review of the preclinical literature and clinical SCI trials relevant to the discovery and current development of Cethrin. RESULTS/CONCLUSION In a recently concluded Phase I/IIa clinical trial involving 37 patients with either cervical or thoracic SCIs, the evidence for Cethrin indicates that topical administration of either 0.3, 1, 3 or 6 mg of the recombinant rho inhibitor following surgical decompression is safe. Alseres has announced that planning is underway for a Phase IIB trial of Cethrin to include a placebo arm to assess better the drugs' clinical efficacy.
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Affiliation(s)
- Darryl C Baptiste
- University Health Network, Toronto Western Hospital, Toronto Western Research Institute, Krembil Neuroscience Centre, Toronto, Ontario, Canada.
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175
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Lonjon N, Kouyoumdjian P, Prieto M, Bauchet L, Haton H, Gaviria M, Privat A, Perrin FE. Early functional outcomes and histological analysis after spinal cord compression injury in rats. J Neurosurg Spine 2010; 12:106-13. [DOI: 10.3171/2009.7.spine0989] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Neuroprotective and repair strategies in spinal cord injuries (SCIs) have been so far largely unsuccessful. One of the prerequisites is the use of appropriate preclinical models to decipher pathophysiological mechanisms; another is the identification of optimal time windows for therapeutic interventions. The authors undertook this study to characterize early motor, sensory, autonomic, and histological outcomes after balloon compression of the spinal cord at the T8–9 level in adult rats.
Methods
A total of 91 rats were used in this study. Spinal cord balloon compression was performed at T8–9 in adult rats by inflation of a 2 Fr Fogarty catheter into the epidural space. The authors first characterized early motor, sensory, and autonomic outcomes of 2 volumes of compression (10 and 15 μl) using behavioral tests and then examined histological outcomes in the spinal cord using Luxol fast blue staining. To further substantiate the characterization of the epidural balloon-compression model, they used a noncompetitive N-methyl-d-aspartate antagonist, GK11, and demonstrated the involvement of excitotoxicity in this model.
Results
Proportional and reproducible functional impairment resulted from compression caused by balloon inflation with either 10 or 15 μl of water and corresponded to the extent of the lesion. Indeed, during the early phase following SCI (1 week postinjury), recovery of locomotor function and bladder control correlated with the volume of inflation, whereas outcomes with respect to sensory function and reflexes were independent of compression severity. Treatment with GK11 significantly improved motor function in all groups of rats 1 week after injury and bladder voiding in the 10-μl injured rats compared to the 15-μl injured rats.
Conclusions
The results of this study demonstrate that spinal balloon-compression injury in the rat is a well-characterized, reproducible, and predictable model to analyze early events following SCI.
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Affiliation(s)
- Nicolas Lonjon
- 1Institut National de la Santé et de la Recherche Médicale U583, Institute for Neurosciences of Montpellier and
- 2Department of Neurosurgery, Gui de Chauliac Hospital
| | - Pascal Kouyoumdjian
- 1Institut National de la Santé et de la Recherche Médicale U583, Institute for Neurosciences of Montpellier and
- 3Orthopedic Department, Centre Hospitalier Universitaire de Nîmes, France; and
| | | | - Luc Bauchet
- 1Institut National de la Santé et de la Recherche Médicale U583, Institute for Neurosciences of Montpellier and
- 2Department of Neurosurgery, Gui de Chauliac Hospital
- 5Centre Mutualiste Neurologique Propara, Montpellier
| | - Henri Haton
- 1Institut National de la Santé et de la Recherche Médicale U583, Institute for Neurosciences of Montpellier and
| | | | - Alain Privat
- 1Institut National de la Santé et de la Recherche Médicale U583, Institute for Neurosciences of Montpellier and
| | - Florence E. Perrin
- 1Institut National de la Santé et de la Recherche Médicale U583, Institute for Neurosciences of Montpellier and
- 6Neuroscience Department, University of the Basque Country, Ikerbasque, Bilbao, Spain
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176
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Kouyoumdjian P, Lonjon N, Prieto M, Haton H, Privat A, Asencio G, Perrin FE, Gaviria M. A remotely controlled model of spinal cord compression injury in mice: toward real-time analysis. J Neurosurg Spine 2009; 11:461-70. [PMID: 19929343 DOI: 10.3171/2009.4.spine0979] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT To date, there has been no efficient therapeutic approach to spinal cord injuries (SCIs). This may be attributable, at least in part, to difficulties in forming predictive and accurate experimental animal models. The authors' previous studies have identified 2 relevant conditions of such a model. The first condition is the ability to compare data derived from rat models of SCI by developing mouse models of SCI that permit access to a large range of transgenic models. The second condition is that the exploration of the consequences of each mechanism of spinal trauma requires modeling the different etiologic aspects of the injury. METHODS To fulfill these 2 conditions a new model of mouse spinal cord compression injury was devised using a thread-driven olive-shaped compressive device. The authors characterized early motor, sensory, and histological outcomes using 3 olive diameters and different compression durations. RESULTS A gradual and reproducible functional severity that correlated with lesion extension was demonstrated in 76 mice. To further substantiate the characterization of this model, a noncompetitive N-methyl-d-aspartate antagonist was administered in 30 mice, which demonstrated the involvement of excitotoxicity in this model. CONCLUSIONS The study demonstrated that spinal olive-compression injury in the mouse is a reproducible, well-characterized, and predictable model for analyzing early events after SCI. The nonmagnetic and remotely controlled design of this model will allow completion of the lesion while the animal is in the MR imaging apparatus, thus permitting further real-time MR imaging studies that will provide insights into the characterization of early events in the spatial and temporal evolution of SCI. Moreover, this model lays the foundation for future in vivo studies of functional and histological outcomes following SCI in genetically engineered animals.
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Affiliation(s)
- Pascal Kouyoumdjian
- Pathophysiology and Therapy of Sensory and Motor Deficits, Institute for Neurosciences of Montpellier, INSERM U583, Saint Eloi Hospital, Montpellier, France
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177
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Donnellan CP, Caldwell K. TENS and FES for sensory impairment and gait dysfunction following removal of spinal cord ependymoma â a case report. PHYSIOTHERAPY RESEARCH INTERNATIONAL 2009; 14:234-41. [DOI: 10.1002/pri.439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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178
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Boulenguez P, Vinay L. Strategies to restore motor functions after spinal cord injury. Curr Opin Neurobiol 2009; 19:587-600. [PMID: 19896827 DOI: 10.1016/j.conb.2009.10.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/23/2009] [Accepted: 10/12/2009] [Indexed: 12/20/2022]
Abstract
This review presents recent advances in the development of strategies to restore posture and locomotion after spinal cord injury (SCI). A set of strategies focusing on the lesion site includes prevention of secondary damages, promotion of axonal sprouting/regeneration, and replacement of lost cells. Other strategies focus on spinal central pattern generators (CPGs). Training promotes functional recovery by enhancing the plasticity of CPGs and these sublesional networks can be reactivated by means of pharmacological or electrical stimulation. It is now clear that substantial functional recovery will require a combination of strategies adapted to each phase following SCI. Finally, improvements in the understanding of the mechanisms underlying spasticity may lead to new treatments of this disabling complication affecting patients with SCI.
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Affiliation(s)
- Pascale Boulenguez
- Laboratoire Plasticité et Physio-Pathologie de Motricité (UMR6196), Centre National de Recherche Scientifique (CNRS) & Aix-Marseille Université, CNRS, 31 chemin Joseph Aiguier, F-13402 Marseille cx 20, France
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179
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Methylprednisolone fails to improve functional and histological outcome following spinal cord injury in rats. Exp Neurol 2009; 220:71-81. [DOI: 10.1016/j.expneurol.2009.07.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/22/2022]
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180
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Margaryan G, Mladinic M, Mattioli C, Nistri A. Extracellular magnesium enhances the damage to locomotor networks produced by metabolic perturbation mimicking spinal injury in the neonatal rat spinal cord in vitro. Neuroscience 2009; 163:669-82. [DOI: 10.1016/j.neuroscience.2009.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 07/01/2009] [Accepted: 07/05/2009] [Indexed: 11/16/2022]
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181
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Dekaban GA, Thawer S. Pathogenic antibodies are active participants in spinal cord injury. J Clin Invest 2009; 119:2881-4. [PMID: 19770517 DOI: 10.1172/jci40839] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The role of B cells and autoimmunity as contributing factors to poor neurological outcomes following spinal cord injury (SCI) is poorly understood. The study by Ankeny et al., in this issue of the JCI, identifies a new immunopathological mechanism arising after SCI in mice (see the related article beginning on page 2990). The study shows that B cells produce pathogenic antibodies that impair lesion repair, resulting in worse neurological outcome. This new understanding of SCI disease pathogenesis, if confirmed in humans, reveals potential avenues for the development of novel neuroprotective immunotherapies.
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Affiliation(s)
- Gregory A Dekaban
- BioTherapeutics Research Laboratory, Molecular Brain Research Group, Robarts Research Institute and Department of Microbiology and Immunology,The University of Western Ontario, 100 Perth Drive, London, Ontario, Canada.
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182
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Treatment of rat spinal cord injury with a Rho-kinase inhibitor and bone marrow stromal cell transplantation. Brain Res 2009; 1295:192-202. [PMID: 19651108 DOI: 10.1016/j.brainres.2009.07.087] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 07/24/2009] [Accepted: 07/25/2009] [Indexed: 01/05/2023]
Abstract
In light of reports that the administration of fasudil, a Rho-kinase inhibitor, improved rats locomotor abilities following spinal cord injury, we hypothesized that combining fasudil with another type of therapy, such as stem cell transplantation, might further improve the level of locomotor recovery. Bone marrow stromal cells (BMSCs) are readily available for stem cell therapy. In the present study, we examined whether fasudil combined with BMSC transplantation would produce synergistic effects on recovery. Adult female Sprague-Dawley rats were subjected to spinal cord contusion injury at the T10 vertebral level using an IH impactor (200 Kdyn). Immediately after contusion, they were administrated fasudil intrathecally for 4 weeks. GFP rat-derived BMSCs (2.5x10(6)) were injected into the lesion site 14 days after contusion. Locomotor recovery was assessed for 9 weeks with BBB scoring. Sensory tests were conducted at 8 weeks. Biotinylated dextran amine (BDA) was injected into the sensory-motor cortex at 9 weeks. In addition to an untreated control group, the study also included a fasudil-only group and a BMSC-only group in order to compare the effects of combined therapy vs. single-agent therapy. Animals were perfused transcardially 11 weeks after contusion, and histological examinations were performed. The combined therapy group showed statistically better locomotor recovery than the untreated control group at 8 and 9 weeks after contusion. Neither of the two single-agent treatments improved open field locomotor function. Sensory tests showed no statistically significant difference by treatment. Histological and immunohistochemical studies provided some supporting evidence for better locomotor recovery following combined therapy. The average area of the cystic cavity was significantly smaller in the fasudil+BMSC group than in the control group. The number of 5-HT nerve fibers was significantly higher in the fasudil+BMSC group than in the control group on the rostral side of the lesion site. BDA-labeled fibers on the caudal side of the lesion epicenter were observed only in the fasudil+BMSC group. On the other hand, only small numbers of GFP-labeled grafted cells remained 9 weeks after transplantation, and these were mainly localized at the site of injection. Double immunofluorescence studies showed no evidence of differentiation of grafted BMSCs into glial cells or neurons. The Rho-kinase inhibitor fasudil combined with BMSC transplantation resulted in better locomotor recovery than occurred in the untreated control group. However, the data failed to demonstrate significant synergism from combined therapy compared with the levels of recovery following single-agent treatment.
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183
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Vinit S, Lovett-Barr MR, Mitchell GS. Intermittent hypoxia induces functional recovery following cervical spinal injury. Respir Physiol Neurobiol 2009; 169:210-7. [PMID: 19651247 DOI: 10.1016/j.resp.2009.07.023] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 07/20/2009] [Accepted: 07/27/2009] [Indexed: 12/13/2022]
Abstract
Respiratory-related complications are the leading cause of death in spinal cord injury (SCI) patients. Few effective SCI treatments are available after therapeutic interventions are performed in the period shortly after injury (e.g. spine stabilization and prevention of further spinal damage). In this review we explore the capacity to harness endogenous spinal plasticity induced by intermittent hypoxia to optimize function of surviving (spared) neural pathways associated with breathing. Two primary questions are addressed: (1) does intermittent hypoxia induce plasticity in spinal synaptic pathways to respiratory motor neurons following experimental SCI? and (2) can this plasticity improve respiratory function? In normal rats, intermittent hypoxia induces serotonin-dependent plasticity in spinal pathways to respiratory motor neurons. Early experiments suggest that intermittent hypoxia also enhances respiratory motor output in experimental models of cervical SCI (cervical hemisection) and that the capacity to induce functional recovery is greater with longer durations post-injury. Available evidence suggests that intermittent hypoxia-induced spinal plasticity has considerable therapeutic potential to treat respiratory insufficiency following chronic cervical spinal injury.
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Affiliation(s)
- Stéphane Vinit
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706-1102, USA.
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184
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Brambilla R, Hurtado A, Persaud T, Esham K, Pearse DD, Oudega M, Bethea JR. Transgenic inhibition of astroglial NF-kappa B leads to increased axonal sparing and sprouting following spinal cord injury. J Neurochem 2009; 110:765-78. [PMID: 19522780 PMCID: PMC4090052 DOI: 10.1111/j.1471-4159.2009.06190.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We previously showed that Nuclear Factor kappaB (NF-kappaB) inactivation in astrocytes leads to improved functional recovery following spinal cord injury (SCI). This correlated with reduced expression of pro-inflammatory mediators and chondroitin sulfate proteoglycans, and increased white matter preservation. Hence we hypothesized that inactivation of astrocytic NF-kappaB would create a more permissive environment for axonal sprouting and regeneration. We induced both contusive and complete transection SCI in GFAP-Inhibitor of kappaB-dominant negative (GFAP-IkappaBalpha-dn) and wild-type (WT) mice and performed retrograde [fluorogold (FG)] and anterograde [biotinylated dextran amine (BDA)] tracing 8 weeks after injury. Following contusive SCI, more FG-labeled cells were found in motor cortex, reticular formation, and raphe nuclei of transgenic mice. Spared and sprouting BDA-positive corticospinal axons were found caudal to the lesion in GFAP-IkappaBalpha-dn mice. Higher numbers of FG-labeled neurons were detected immediately rostral to the lesion in GFAP-IkappaBalpha-dn mice, accompanied by increased expression of synaptic and axonal growth-associated molecules. After transection, however, no FG-labeled neurons or BDA-filled axons were found rostral and caudal to the lesion, respectively, in either genotype. These data demonstrated that inhibiting astroglial NF-kappaB resulted in a growth-supporting terrain promoting sparing and sprouting, rather than regeneration, of supraspinal and propriospinal circuitries essential for locomotion, hence contributing to the improved functional recovery observed after SCI in GFAP-IkappaBalpha-dn mice.
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Affiliation(s)
- Roberta Brambilla
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Andres Hurtado
- International Center for Spinal Cord Injury, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205
| | - Trikaldarshi Persaud
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Kim Esham
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Damien D. Pearse
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
- Neuroscience Program, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Martin Oudega
- Department of Physical Medicine and Rehabilitation and Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - John R. Bethea
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
- Neuroscience Program, Miller School of Medicine, University of Miami, Miami, FL 33136
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33136
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185
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186
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Cohen DM, Patel CB, Ahobila-Vajjula P, Sundberg LM, Chacko T, Liu SJ, Narayana PA. Blood-spinal cord barrier permeability in experimental spinal cord injury: dynamic contrast-enhanced MRI. NMR IN BIOMEDICINE 2009; 22:332-41. [PMID: 19023867 PMCID: PMC2741317 DOI: 10.1002/nbm.1343] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
After a primary traumatic injury, spinal cord tissue undergoes a series of pathobiological changes, including compromised blood-spinal cord barrier (BSCB) integrity. These vascular changes occur over both time and space. In an experimental model of spinal cord injury (SCI), longitudinal dynamic contrast-enhanced MRI (DCE-MRI) studies were performed up to 56 days after SCI to quantify spatial and temporal changes in the BSCB permeability in tissue that did not show any visible enhancement on the post-contrast MRI (non-enhancing tissue). DCE-MRI data were analyzed using a two-compartment pharmacokinetic model. These studies demonstrate gradual restoration of BSCB with post-SCI time. However, on the basis of DCE-MRI, and confirmed by immunohistochemistry, the BSCB remained compromised even at 56 days after SCI. In addition, open-field locomotion was evaluated using the 21-point Basso-Beattie-Bresnahan scale. A significant correlation between decreased BSCB permeability and improved locomotor recovery was observed.
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187
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Abstract
Spinal cord injury research has greatly expanded in recent years, but our understanding of the mechanisms that underlie the functional recovery that can occur over the weeks and months following the initial injury, is far from complete. To grasp the scope of the problem, it is important to begin by defining the sensorimotor pathways that might be involved by a spinal injury. This is done in the rodent and nonhuman primate, which are two of the most commonly used animal models in basic and translational spinal injury research. Many of the better known experimentally induced models are then reviewed in terms of the pathways they involve and the reorganization and recovery that have been shown to follow. The better understood neuronal mechanisms mediating such post-injury plasticity, including dendritic spine growth and axonal sprouting, are then examined.
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Affiliation(s)
- Corinna Darian-Smith
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California 94305, USA.
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188
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Wang X, Chen W, Liu W, Wu J, Shao Y, Zhang X. The role of thrombospondin-1 and transforming growth factor-beta after spinal cord injury in the rat. J Clin Neurosci 2009; 16:818-21. [PMID: 19342245 DOI: 10.1016/j.jocn.2008.09.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/15/2008] [Accepted: 09/18/2008] [Indexed: 01/08/2023]
Abstract
Spinal cord injury (SCI) continues to result in high morbidity and mortality throughout the world. An effective neuroprotective agent is still not available to counteract secondary damage caused by traumatic injury. Thrombospondin-1 (TSP-1) and transforming growth factor-beta (TGF-beta) have a role in angiogenesis, scar deposition, inflammation and may affect astrocyte phenotype and mobility. We investigated the role of TSP-1 and TGF-beta in a model of spinal cord injury in rats. Forty female Sprague-Dawley rats were randomly divided into two equal groups: the experimental group was subject to SCI using an impactor and the sham-operated group was not subject to SCI. These animals were sacrificed at 12 h and 24 h after SCI for immunochemistry and Western blot analysis of the injured spinal segment for the expression of the TSP-1 and TGF-beta proteins. We found that TSP-1 and TGF-beta expression increased immediately after SCI in the injured segment. After 12 h, TSP-1 concentrations increased more rapidly and dramatically than TGF-beta in the injured segment of the spinal cord. Elevations in TSP-1 and TGF-beta concentrations persisted for 24 h after injury. These results show that elevated expression of TSP-1 and TGF-beta can be detected in the injured segment of the spinal cord 12 and 24 h after injury. Thus, TSP-1 and TGF-beta may have a role in SCI.
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Affiliation(s)
- Xianghua Wang
- Department of Orthopedics, The Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China
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189
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Fitzsimmons NA, Lebedev MA, Peikon ID, Nicolelis MAL. Extracting kinematic parameters for monkey bipedal walking from cortical neuronal ensemble activity. Front Integr Neurosci 2009; 3:3. [PMID: 19404411 PMCID: PMC2659168 DOI: 10.3389/neuro.07.003.2009] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 02/23/2009] [Indexed: 11/18/2022] Open
Abstract
The ability to walk may be critically impacted as the result of neurological injury or disease. While recent advances in brain–machine interfaces (BMIs) have demonstrated the feasibility of upper-limb neuroprostheses, BMIs have not been evaluated as a means to restore walking. Here, we demonstrate that chronic recordings from ensembles of cortical neurons can be used to predict the kinematics of bipedal walking in rhesus macaques – both offline and in real time. Linear decoders extracted 3D coordinates of leg joints and leg muscle electromyograms from the activity of hundreds of cortical neurons. As more complex patterns of walking were produced by varying the gait speed and direction, larger neuronal populations were needed to accurately extract walking patterns. Extraction was further improved using a switching decoder which designated a submodel for each walking paradigm. We propose that BMIs may one day allow severely paralyzed patients to walk again.
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190
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Rudhe C, van Hedel HJA. Upper Extremity Function in Persons with Tetraplegia: Relationships Between Strength, Capacity, and the Spinal Cord Independence Measure. Neurorehabil Neural Repair 2009; 23:413-21. [DOI: 10.1177/1545968308331143] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective. To quantify the relationship between the Spinal Cord Independence Measure III (SCIM III), arm and hand muscle strength, and hand function tests in persons with tetraplegia. Methods. A total of 29 individuals with tetraplegia (motor level between cervical 4 and thoracic 1; sensory-motor complete and incomplete) participated. The total score, category scores, and separate items of the SCIM III were compared to the upper extremity motor score (UEMS), an extended manual muscle test (MMT) for 11 upper extremity muscles, and 6 functional capacity tests of the hand. Spearman's correlation coefficients ( rs) and regression analyses were performed. Results. The SCIM III sum score correlated well with the sum scores of the 3 tests ( rs ≥ .76). The SCIM III self-care category correlated better with the tests ( rs ≥ .80) compared to the other categories ( r s ≤ .72). The SCIM III self-care item “grooming” highly correlated with muscle strength and hand capacity items ( rs ≥ .80). A combination of hand muscle tests and the key grasping task explained over 90% of the variability in the self-care category scores. Conclusions. The SCIM III self-care category reflects upper extremity performance as it contains especially useful and valid items that relate to upper extremity function and capacity tests.
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Affiliation(s)
- Claudia Rudhe
- The GRASSP Study Group (Graded Redefined Assessment of Strength, Sensibility, and Prehension), EM-SCI Study Group (European Multicenter Study on Human Spinal Cord Injury), Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Hubertus J. A. van Hedel
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland, , EM-SCI Study Group (European Multicenter Study on Human Spinal Cord Injury)
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191
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Lee MY, Chen L, Toborek M. Nicotine attenuates iNOS expression and contributes to neuroprotection in a compressive model of spinal cord injury. J Neurosci Res 2009; 87:937-47. [DOI: 10.1002/jnr.21901] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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192
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Schwartz M, London A, Shechter R. Boosting T-cell immunity as a therapeutic approach for neurodegenerative conditions: The role of innate immunity. Neuroscience 2009; 158:1133-42. [DOI: 10.1016/j.neuroscience.2008.12.013] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 12/09/2008] [Accepted: 12/10/2008] [Indexed: 12/14/2022]
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193
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Gervasi NM, Kwok JC, Fawcett JW. Role of extracellular factors in axon regeneration in the CNS: implications for therapy. Regen Med 2009; 3:907-23. [PMID: 18947312 DOI: 10.2217/17460751.3.6.907] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The glial scar that forms after an injury to the CNS contains molecules that are inhibitory to axon growth. Understanding of the mechanisms of inhibition has allowed the development of therapeutic strategies aimed at promoting axon regeneration. Promising results have been obtained in animal models, and some therapies are undergoing clinical trials. This offers great hope for achievement of functional recovery after CNS injury.
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Affiliation(s)
- Noreen M Gervasi
- Cambridge University Centre for Brain Repair, ED Adrian Building, Forvie Site, Robinson Way, Cambridge CB22PY, UK.
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194
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Ahmed Z, Wieraszko A. Combined effects of acrobatic exercise and magnetic stimulation on the functional recovery after spinal cord lesions. J Neurotrauma 2009; 25:1257-69. [PMID: 18986227 DOI: 10.1089/neu.2008.0626] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The objective of the study was to determine whether physical exercise combined with epidural spinal cord magnetic stimulation could improve recovery after injury of the spinal cord. Spinal cord lesioning in mice resulted in reduced locomotor function and negatively affected the muscle strength tested in vitro. Acrobatic exercise attenuated the behavioral effects of spinal cord injury. The exposure to magnetic fields facilitated further this improvement. The progress in behavioral recovery was correlated with reduced muscle degeneration and enhanced muscle contraction. The acrobatic exercise combined with stimulation with magnetic fields significantly facilitates behavioral recovery and muscle physiology in mice following spinal cord injury.
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Affiliation(s)
- Zaghloul Ahmed
- Department of Physical Therapy, and CSI/IBR Center for Developmental Neuroscience, The College of Staten Island/CUNY, Staten Island, New York 10314, USA.
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195
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Zhang J, Zhang A, Sun Y, Cao X, Zhang N. Treatment with Immunosuppressants FTY720 and Tacrolimus Promotes Functional Recovery after Spinal Cord Injury in Rats. TOHOKU J EXP MED 2009; 219:295-302. [DOI: 10.1620/tjem.219.295] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Jie Zhang
- Department of Orthopedics, First Affiliated Hospital, Nanjing Medical University
| | - Ailiang Zhang
- Department of Orthopedics, First Affiliated Hospital, Nanjing Medical University
| | - Yu Sun
- Department of Orthopedics, First Affiliated Hospital, Nanjing Medical University
| | - Xiaojian Cao
- Department of Orthopedics, First Affiliated Hospital, Nanjing Medical University
| | - Ning Zhang
- Department of Orthopedics, First Affiliated Hospital, Nanjing Medical University
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196
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Ban DX, Kong XH, Feng SQ, Ning GZ, Chen JT, Guo SF. Intraspinal cord graft of autologous activated Schwann cells efficiently promotes axonal regeneration and functional recovery after rat's spinal cord injury. Brain Res 2008; 1256:149-61. [PMID: 19103176 DOI: 10.1016/j.brainres.2008.11.098] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 11/25/2008] [Accepted: 11/26/2008] [Indexed: 01/03/2023]
Abstract
Basic research in spinal cord injury (SCI) has made great strides in recent years, and some new insights and strategies have been applied in promoting effective axonal regrowth and sprouting. However, a relatively safe and efficient transplantation technique remains undetermined. This study, therefore, was aimed to address a question of how to graft Schwann cells to achieve the best possible therapeutic effects. To clarify the issue, the rats were subjected to spinal cord injury at T10. Autologous activated Schwann cells (AASCs) were obtained by prior ligation of saphenous nerve and subsequently isolated and purified in vitro and then grafted into spinal cord-injured rats via three different routes (group I: intravenous, group II: intrathecal and group III: intraspinal cord). Neurologic function was serially evaluated by Basso, Beattie, Bresnahan locomotor rating scale and footprint analysis. We also evaluated the migration of the transplanted cells at 2 weeks after transplantation. Using biotinylated dextran amine (BDA) anterograde tracing, we demonstrated that more regenerative axons of corticospinal tract (CST) surrounding the injured cavity in group III than those in the other two groups, and we also confirmed it further by quantitative analysis. The microenvironment surrounding the injured spinal cord has been improved to the greatest extent in group III, as determined by immunohistological staining. Relatively complete myelin sheaths and more neurofilaments in axons were found in groups II and III than those in group I under electron microscopy. The results showed that intraspinal cord injection of AASCs promoted recovery of hindlimb locomotor function of injured rats more efficiently than the other grafting routes. In addition, intact myelin sheaths and sufficient neurofilaments in axons were not adequate for full functional recovery after SCI, suggesting that reestablishment of normal synaptic connection is indispensable. The findings in this study strongly suggest that transplantation of AASCs directly into the spinal cord may be one of the promising candidates for potential scaffold for injured spinal cord, and such strategy of transplantation of AASCs could be hopeful to treat patients with SCI.
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Affiliation(s)
- De-Xiang Ban
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin Heping District Anshan Road 154, Tianjin 300052, PR China
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197
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Affiliation(s)
- Woo-Yang Kim
- Neuroscience Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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198
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Li L, Li J, Zhu Y, Fan G. Ephedra sinica inhibits complement activation and improves the motor functions after spinal cord injury in rats. Brain Res Bull 2008; 78:261-6. [PMID: 19000748 DOI: 10.1016/j.brainresbull.2008.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 10/08/2008] [Accepted: 10/08/2008] [Indexed: 01/01/2023]
Abstract
The activation of complement system has been known as an important and significant reaction against the secondary injury after spinal cord injury (SCI). In the present study, we investigated the effect of Ephedra sinica to the inflammation or complement system of injured spinal cord and the influence to the functional recovery after spinal cord injury in rats. We prepared the complement-inhibiting component from E. sinica. Contusive spinal cord injury was induced to Sprague-Dawley rats. We administrated the product from E. sinica to E. sinica group, while distilled water was administered to the control group by gavage after SCI. Complement hemolytic activity (CH50), expression of C3 and C9, myeloperoxidase activity, and motor function were evaluated in E. sinica group and control group. The CH50, complement depositions, and myeloperoxidase activity in the E. sinica group were significantly reduced as compared to the control group. The motor function of E. sinica group was significantly improved from the 7th day as compared with the control group. The results demonstrated that E. sinica might reduce inflammation and improve motor function in rats after spinal cord injury by inhibiting complement activation. The present study has shown that complement system is playing an important role in spinal cord injury, and the possibility of a new therapy strategy, inhibiting or controlling the complement activation and inflammation, for spinal cord injury.
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Affiliation(s)
- Liangman Li
- Department of Orthopaedics, First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Heping District, Shenyang, 110001, China
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199
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Frigon A, Rossignol S. Partial denervation of ankle extensors prior to spinalization in cats impacts the expression of locomotion and the phasic modulation of reflexes. Neuroscience 2008; 158:1675-90. [PMID: 19056469 DOI: 10.1016/j.neuroscience.2008.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 11/04/2008] [Accepted: 11/05/2008] [Indexed: 10/21/2022]
Abstract
Following peripheral nerve sections some locomotor deficits appear which are gradually compensated for by spinal and supraspinal mechanisms. The present work is aimed at identifying contributions of both types of mechanisms. We performed a denervation of the left lateral gastrocnemius-soleus (LGS) muscles in three cats which was followed by a spinalization at the 13th thoracic segment. Three other cats were not denervated prior to spinalization (i.e. intact) and served as controls. Over the years, in our laboratory, there have been no instances in which cats did not express spinal locomotion with treadmill training and/or clonidine administration. After spinalization, cats were trained on a treadmill to express spinal locomotion. Reflexes, evoked by stimulating the left tibial nerve at the ankle, the electromyography of several hindlimb muscles, and kinematics were recorded during locomotion before and after denervation, during recovery, and following complete spinalization. Denervating the left LGS before spinalization induced considerable variability in the expression of spinal locomotion from one cat to another, which was not observed in the three controls. Variability ranged from a greater ankle yield in the denervated limb in one cat to inability to recover locomotion after spinalization in another. In the two denervated cats that recovered locomotion after spinalization, some reflex changes differed from "normal" spinal cats (i.e. intact at the time of spinalization), suggesting that reorganization of spinal circuits after spinalization is dissimilar to what normally takes place if denervation is performed before spinalization. First, we conclude that the transient locomotor deficits initially incurred following the LGS denervation in cats with an intact spinal cord reappear after complete spinalization indicating that supraspinal mechanisms were involved in maintaining the adapted locomotion. Second, the reappearance of locomotor deficits and/or impairment in expressing spinal locomotion suggests that spinal mechanisms were profoundly altered to compensate for the initial denervation partly because the reflex modulation is abnormal. If the same denervation is performed after spinalization only transient deficits are observed and spinal locomotion is not compromised.
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Affiliation(s)
- A Frigon
- Department of Physiology, Université de Montréal, Station Centre-Ville, Montreal, Quebec, Canada H3C 3J7.
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200
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Hawryluk GWJ, Fehlings MG. The center of the spinal cord may be central to its repair. Cell Stem Cell 2008; 3:230-2. [PMID: 18786407 DOI: 10.1016/j.stem.2008.08.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Gregory W J Hawryluk
- Division of Genetics and Development, Toronto Western Research Institute, University of Toronto, Canada
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