1
|
Jiang Y, Cai Y, Yang N, Gao S, Li Q, Pang Y, Su P. Molecular mechanisms of spinal cord injury repair across vertebrates: A comparative review. Eur J Neurosci 2024; 60:4552-4568. [PMID: 38978308 DOI: 10.1111/ejn.16462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 05/09/2024] [Accepted: 06/20/2024] [Indexed: 07/10/2024]
Abstract
In humans and other adult mammals, axon regeneration is difficult in axotomized neurons. Therefore, spinal cord injury (SCI) is a devastating event that can lead to permanent loss of locomotor and sensory functions. Moreover, the molecular mechanisms of axon regeneration in vertebrates are not very well understood, and currently, no effective treatment is available for SCI. In striking contrast to adult mammals, many nonmammalian vertebrates such as reptiles, amphibians, bony fishes and lampreys can spontaneously resume locomotion even after complete SCI. In recent years, rapid progress in the development of next-generation sequencing technologies has offered valuable information on SCI. In this review, we aimed to provide a comparison of axon regeneration process across classical model organisms, focusing on crucial genes and signalling pathways that play significant roles in the regeneration of individually identifiable descending neurons after SCI. Considering the special evolutionary location and powerful regenerative ability of lamprey and zebrafish, they will be the key model organisms for ongoing studies on spinal cord regeneration. Detailed study of SCI in these model organisms will help in the elucidation of molecular mechanisms of neuron regeneration across species.
Collapse
Affiliation(s)
- Ying Jiang
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Yang Cai
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Ning Yang
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Si Gao
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Qingwei Li
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Yue Pang
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| | - Peng Su
- College of Life Science, Liaoning Normal University, Dalian, China
- Lamprey Research Center, Liaoning Normal University, Dalian, China
- Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, China
| |
Collapse
|
2
|
Malomo T, Allard Brown A, Bale K, Yung A, Kozlowski P, Heran M, Streijger F, Kwon BK. Quantifying Intraparenchymal Hemorrhage after Traumatic Spinal Cord Injury: A Review of Methodology. J Neurotrauma 2022; 39:1603-1635. [PMID: 35538847 DOI: 10.1089/neu.2021.0317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Intraparenchymal hemorrhage (IPH) after a traumatic injury has been associated with poor neurological outcomes. Although IPH may result from the initial mechanical trauma, the blood and its breakdown products have potentially deleterious effects. Further, the degree of IPH has been correlated with injury severity and the extent of subsequent recovery. Therefore, accurate evaluation and quantification of IPH following traumatic spinal cord injury (SCI) is important to define treatments' effects on IPH progression and secondary neuronal injury. Imaging modalities, such as magnetic resonance imaging (MRI) and ultrasound (US), have been explored by researchers for the detection and quantification of IPH following SCI. Both quantitative and semiquantitative MRI and US measurements have been applied to objectively assess IPH following SCI, but the optimal methods for doing so are not well established. Studies in animal SCI models (rodent and porcine) have explored US and histological techniques in evaluating SCI and have demonstrated the potential to detect and quantify IPH. Newer techniques using machine learning algorithms (such as convolutional neural networks [CNN]) have also been studied to calculate IPH volume and have yielded promising results. Despite long-standing recognition of the potential pathological significance of IPH within the spinal cord, quantifying IPH with MRI or US is a relatively new area of research. Further studies are warranted to investigate their potential use. Here, we review the different and emerging quantitative MRI, US, and histological approaches used to detect and quantify IPH following SCI.
Collapse
Affiliation(s)
- Toluyemi Malomo
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aysha Allard Brown
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kirsten Bale
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrew Yung
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Piotr Kozlowski
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Manraj Heran
- Department of Radiology, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Femke Streijger
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian K Kwon
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,Vancouver Spine Surgery Institute, Department of Orthopaedics, and Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
3
|
Canty AJ, Jackson JS, Huang L, Trabalza A, Bass C, Little G, Tortora M, Khan S, De Paola V. In vivo imaging of injured cortical axons reveals a rapid onset form of Wallerian degeneration. BMC Biol 2020; 18:170. [PMID: 33208154 PMCID: PMC7677840 DOI: 10.1186/s12915-020-00869-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 09/16/2020] [Indexed: 12/22/2022] Open
Abstract
Background Despite the widespread occurrence of axon and synaptic loss in the injured and diseased nervous system, the cellular and molecular mechanisms of these key degenerative processes remain incompletely understood. Wallerian degeneration (WD) is a tightly regulated form of axon loss after injury, which has been intensively studied in large myelinated fibre tracts of the spinal cord, optic nerve and peripheral nervous system (PNS). Fewer studies, however, have focused on WD in the complex neuronal circuits of the mammalian brain, and these were mainly based on conventional endpoint histological methods. Post-mortem analysis, however, cannot capture the exact sequence of events nor can it evaluate the influence of elaborated arborisation and synaptic architecture on the degeneration process, due to the non-synchronous and variable nature of WD across individual axons. Results To gain a comprehensive picture of the spatiotemporal dynamics and synaptic mechanisms of WD in the nervous system, we identify the factors that regulate WD within the mouse cerebral cortex. We combined single-axon-resolution multiphoton imaging with laser microsurgery through a cranial window and a fluorescent membrane reporter. Longitudinal imaging of > 150 individually injured excitatory cortical axons revealed a threshold length below which injured axons consistently underwent a rapid-onset form of WD (roWD). roWD started on average 20 times earlier and was executed 3 times slower than WD described in other regions of the nervous system. Cortical axon WD and roWD were dependent on synaptic density, but independent of axon complexity. Finally, pharmacological and genetic manipulations showed that a nicotinamide adenine dinucleotide (NAD+)-dependent pathway could delay cortical roWD independent of transcription in the damaged neurons, demonstrating further conservation of the molecular mechanisms controlling WD in different areas of the mammalian nervous system. Conclusions Our data illustrate how in vivo time-lapse imaging can provide new insights into the spatiotemporal dynamics and synaptic mechanisms of axon loss and assess therapeutic interventions in the injured mammalian brain.
Collapse
Affiliation(s)
- Alison Jane Canty
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Australia.
| | - Johanna Sara Jackson
- Dementia Research Institute at Imperial College, Department of Brain Sciences, Imperial College London, London, W12 0NN, UK
| | - Lieven Huang
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Antonio Trabalza
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Cher Bass
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Graham Little
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Maria Tortora
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Shabana Khan
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Vincenzo De Paola
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK. .,Medical Research Council London Institute of Medical Sciences, London, W12 0NN, UK.
| |
Collapse
|
4
|
Mushlin HM, Lessing N, Wessell AP, Chryssikos T, Pratt N, Caffes N, Oliver J, Aarabi B, Schwartzbauer G. The Effect of Elevated Mean Arterial Blood Pressure in Cervical Traumatic Spinal Cord Injury with Hemorrhagic Contusion. World Neurosurg 2020; 144:e405-e413. [PMID: 32889182 DOI: 10.1016/j.wneu.2020.08.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/23/2020] [Accepted: 08/23/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Hemorrhagic contusion in cervical spinal cord injury (CSCI) is poorly understood. We investigated hemorrhagic expansion in patients with CSCI with an assigned elevated mean arterial pressure (MAP) goal of >85 mm Hg. The change in hemorrhagic area and long-term follow-up data ≥6 months after injury was studied. METHODS A retrospective review was performed from 2005 to 2016 to identify patients with motor complete CSCI with 2 cervical magnetic resonance imaging (MRI) scans within 7 days of injury showing evidence of hemorrhagic contusion and assigned a MAP goal of >85 mm Hg for 7 days. T2-weighted MRI was used to calculate the hemorrhagic surface area in the sagittal plane. A calculated MAP was recorded for each blood pressure measure between the initial and follow-up MRI scans. The American Spinal Injury Association impairment scale (AIS) and American Spinal Injury Association motor scores were recorded at the final follow-up examination at ≥6 months. RESULTS A total of 193 patients were identified. The mean change in the hemorrhagic area was 24.0 mm2. Of the 193 patients, the AIS grade was A for 114 and B for 79 patients. Multiple logistic regression analysis demonstrated that the MAP and systolic blood pressure were nonsignificant predictors of hemorrhagic contusion expansion. An increased hemorrhagic contusion area on the follow-up MRI scan was associated with a reduced odds of AIS improvement of ≥1 and ≥2 points (odds ratio, 0.97; 95% confidence interval, 0.87-0.97; P = 0.028; and odds ratio, 0.92; 95% confidence interval, 0.99-1.13; P = 0.008, respectively) at the final ≥6-month follow-up examination. CONCLUSION The present study investigated the clinical safety of elevated MAP goals for patients with CSCI and hemorrhagic contusion. Elevated MAPs did not significantly increase the risk of hemorrhagic expansion in those with CSCI. We have also reported the use of hemorrhagic contusion size as a potential radiographic biomarker for neurological outcomes.
Collapse
Affiliation(s)
- Harry M Mushlin
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA.
| | - Noah Lessing
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Aaron P Wessell
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Timothy Chryssikos
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Nathan Pratt
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Nicholas Caffes
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jeffrey Oliver
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Bizhan Aarabi
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA; Program in Trauma, R. Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, Maryland, USA
| | - Gary Schwartzbauer
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA; Program in Trauma, R. Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, Maryland, USA
| |
Collapse
|
5
|
Innovative mouse model mimicking human-like features of spinal cord injury: efficacy of Docosahexaenoic acid on acute and chronic phases. Sci Rep 2019; 9:8883. [PMID: 31222077 PMCID: PMC6586623 DOI: 10.1038/s41598-019-45037-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 05/28/2019] [Indexed: 02/08/2023] Open
Abstract
Traumatic spinal cord injury has dramatic consequences and a huge social impact. We propose a new mouse model of spinal trauma that induces a complete paralysis of hindlimbs, still observable 30 days after injury. The contusion, performed without laminectomy and deriving from the pressure exerted directly on the bone, mimics more closely many features of spinal injury in humans. Spinal cord was injured at thoracic level 10 (T10) in adult anesthetized female CD1 mice, mounted on stereotaxic apparatus and connected to a precision impactor device. Following severe injury, we evaluated motor and sensory functions, and histological/morphological features of spinal tissue at different time points. Moreover, we studied the effects of early and subchronic administration of Docosahexaenoic acid, investigating functional responses, structural changes proximal and distal to the lesion in primary and secondary injury phases, proteome modulation in injured spinal cord. Docosahexaenoic acid was able i) to restore behavioural responses and ii) to induce pro-regenerative effects and neuroprotective action against demyelination, apoptosis and neuroinflammation. Considering the urgent health challenge represented by spinal injury, this new and reliable mouse model together with the positive effects of docosahexaenoic acid provide important translational implications for promising therapeutic approaches for spinal cord injuries.
Collapse
|
6
|
Kjell J, Olson L. Rat models of spinal cord injury: from pathology to potential therapies. Dis Model Mech 2017; 9:1125-1137. [PMID: 27736748 PMCID: PMC5087825 DOI: 10.1242/dmm.025833] [Citation(s) in RCA: 237] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A long-standing goal of spinal cord injury research is to develop effective spinal cord repair strategies for the clinic. Rat models of spinal cord injury provide an important mammalian model in which to evaluate treatment strategies and to understand the pathological basis of spinal cord injuries. These models have facilitated the development of robust tests for assessing the recovery of locomotor and sensory functions. Rat models have also allowed us to understand how neuronal circuitry changes following spinal cord injury and how recovery could be promoted by enhancing spontaneous regenerative mechanisms and by counteracting intrinsic inhibitory factors. Rat studies have also revealed possible routes to rescuing circuitry and cells in the acute stage of injury. Spatiotemporal and functional studies in these models highlight the therapeutic potential of manipulating inflammation, scarring and myelination. In addition, potential replacement therapies for spinal cord injury, including grafts and bridges, stem primarily from rat studies. Here, we discuss advantages and disadvantages of rat experimental spinal cord injury models and summarize knowledge gained from these models. We also discuss how an emerging understanding of different forms of injury, their pathology and degree of recovery has inspired numerous treatment strategies, some of which have led to clinical trials. Summary: In this Review, we discuss the advantages and disadvantages of the rat for studies of experimental spinal cord injury and summarize the knowledge gained from such studies.
Collapse
Affiliation(s)
- Jacob Kjell
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Munich 80336, Germany
| | - Lars Olson
- Department of Neuroscience, Karolinska Institutet, Stockholm 171 77, Sweden
| |
Collapse
|
7
|
Filous AR, Schwab JM. Determinants of Axon Growth, Plasticity, and Regeneration in the Context of Spinal Cord Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 188:53-62. [PMID: 29030051 DOI: 10.1016/j.ajpath.2017.09.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/15/2017] [Accepted: 09/21/2017] [Indexed: 12/30/2022]
Abstract
The mechanisms that underlie recovery after injury of the central nervous system have rarely been definitively established. Axon regrowth remains the major prerequisite for plasticity, regeneration, circuit formation, and eventually functional recovery. The attributed functional relevance of axon regrowth, however, will depend on several subsequent conditional neurobiological modifications, including myelination and synapse formation, but also pruning of aberrant connectivity. Despite the ability to revamp axon outgrowth by altering an increasing number of extracellular and intracellular targets, disentangling which axons are responsible for the recovery of function from those that are functionally silent, or even contributing to aberrant functions, represents a pertinent void in our understanding, challenging the intuitive translational link between anatomical and functional regeneration. Anatomic hallmarks of regeneration are not static and are largely activity dependent. Herein, we survey mechanisms leading to the formation of dystrophic growth cone at the injured axonal tip, the subsequent axonal dieback, and the molecular determinants of axon growth, plasticity, and regeneration in the context of spinal cord injury.
Collapse
Affiliation(s)
- Angela R Filous
- Spinal Cord Injury Division, Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, Ohio.
| | - Jan M Schwab
- Spinal Cord Injury Division, Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Department of Physical Medicine and Rehabilitation, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Center for Brain and Spinal Cord Repair, Spinal Cord Injury Medicine, The Ohio State University, Wexner Medical Center, Columbus, Ohio.
| |
Collapse
|
8
|
Altinova H, Möllers S, Deumens R, Gerardo-Nava J, Führmann T, van Neerven SGA, Bozkurt A, Mueller CA, Hoff HJ, Heschel I, Weis J, Brook GA. Functional recovery not correlated with axon regeneration through olfactory ensheathing cell-seeded scaffolds in a model of acute spinal cord injury. Tissue Eng Regen Med 2016; 13:585-600. [PMID: 30603440 DOI: 10.1007/s13770-016-9115-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/03/2016] [Accepted: 02/18/2016] [Indexed: 12/18/2022] Open
Abstract
The implantation of bioengineered scaffolds into lesion-induced gaps of the spinal cord is a promising strategy for promoting functional tissue repair because it can be combined with other intervention strategies. Our previous investigations showed that functional improvement following the implantation of a longitudinally microstructured collagen scaffold into unilateral mid-cervical spinal cord resection injuries of adult Lewis rats was associated with only poor axon regeneration within the scaffold. In an attempt to improve graft-host integration as well as functional recovery, scaffolds were seeded with highly enriched populations of syngeneic, olfactory bulb-derived ensheathing cells (OECs) prior to implantation into the same lesion model. Regenerating neurofilament-positive axons closely followed the trajectory of the donor OECs, as well as that of the migrating host cells within the scaffold. However, there was only a trend for increased numbers of regenerating axons above that supported by non-seeded scaffolds or in the untreated lesions. Nonetheless, significant functional recovery in skilled forelimb motor function was observed following the implantation of both seeded and non-seeded scaffolds which could not be correlated to the extent of axon regeneration within the scaffold. Mechanisms other than simple bridging of axon regeneration across the lesion must be responsible for the improved motor function.
Collapse
Affiliation(s)
- Haktan Altinova
- Department of Neurosurgery, Evangelic Hospital Bethel, Bielefeld, Germany.,2Institute of Neuropathology, Uniklinik RWTH Aachen University, Aachen, Germany.,Jülich-Aachen Research Alliance-Translational Brain Medicine (JARA Brain), Jülich, Germany.,4Department of Neurosurgery, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Sven Möllers
- 5Charité Stem Cell Facility, Charité University Hospital, Berlin, Germany
| | - Ronald Deumens
- 2Institute of Neuropathology, Uniklinik RWTH Aachen University, Aachen, Germany.,Jülich-Aachen Research Alliance-Translational Brain Medicine (JARA Brain), Jülich, Germany.,6Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Jose Gerardo-Nava
- 2Institute of Neuropathology, Uniklinik RWTH Aachen University, Aachen, Germany.,Jülich-Aachen Research Alliance-Translational Brain Medicine (JARA Brain), Jülich, Germany
| | - Tobias Führmann
- 7Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Ontario, Canada
| | | | - Ahmet Bozkurt
- 8Department of Plastic, Reconstructive and Hand Surgery, Burn Centre, Uniklinik RWTH Aachen University, Aachen, Germany.,9Department of Plastic and Aesthetic, Reconstructive and Hand Surgery, Center for Reconstructive Microsurgery and Peripheral Nerve Surgery (ZEMPEN), Agaplesion Markus Hospital Frankfurt, Academic Hospital of Johann Wolfgang von Goethe University, Frankfurt, Germany
| | | | - Hans Joachim Hoff
- Department of Neurosurgery, Evangelic Hospital Bethel, Bielefeld, Germany
| | | | - Joachim Weis
- 2Institute of Neuropathology, Uniklinik RWTH Aachen University, Aachen, Germany.,Jülich-Aachen Research Alliance-Translational Brain Medicine (JARA Brain), Jülich, Germany
| | - Gary Anthony Brook
- 2Institute of Neuropathology, Uniklinik RWTH Aachen University, Aachen, Germany.,Jülich-Aachen Research Alliance-Translational Brain Medicine (JARA Brain), Jülich, Germany
| |
Collapse
|
9
|
Longitudinal enlargement of the lesion after spinal cord injury in the rat: a consequence of malignant edema? Spinal Cord 2016; 55:255-263. [PMID: 27645264 DOI: 10.1038/sc.2016.133] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/29/2016] [Accepted: 07/19/2016] [Indexed: 11/08/2022]
Abstract
STUDY DESIGN Experimental animal study. OBJECTIVES Quantitative analysis of secondary changes in lesion size after experimental spinal cord injury (SCI) in the rat, with special emphasis to the formation of dorsal column lesions. SETTING Slovakia. METHODS After SCI in the rat, animals survived for different periods ranging from 5 min to 7 days. Their whole spinal cords were cut transversally into 1 mm thick slabs. On each slab, the lesion profile was outlined. The overall shape of the lesion was reconstructed from a series of consecutive profiles and its length was measured. RESULTS Immediately after injury, a spindle-shaped hemorrhagic contusive lesion was observed, with the length of ~15 mm. After a quiescent phase lasting for at least 1 h, there was a dramatic secondary enlargement of the lesion and its length increased up to 40 mm between 1 and 48 h. The fully developed lesion consisted of the spindle-shaped epicenter and long cranial and caudal protrusions located in the midline between dorsal columns. CONCLUSION We propose that secondary enlargement of the lesion can be explained by posttraumatic swelling. The expanding tissues are pushed out in longitudinal axis along the mechanically weakest parts of the spinal cord. Additional data that support this hypothesis are presented. Our findings indicate that malignant posttraumatic edema might have an important role in pathomechanisms of secondary injury after SCI.
Collapse
|
10
|
Steward O, Willenberg R. Rodent spinal cord injury models for studies of axon regeneration. Exp Neurol 2016; 287:374-383. [PMID: 27374113 DOI: 10.1016/j.expneurol.2016.06.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 06/28/2016] [Indexed: 11/29/2022]
Abstract
For over a century, axon regeneration has been considered the Holy Grail for spinal cord injury (SCI) repair. Although there are other factors that could contribute to improving function, restoring the long motor and sensory tracts that are interrupted by SCI has the greatest potential for actually reversing paralysis, restoring the brain's control of autonomic functions mediated by sympathetic and parasympathetic circuits of the spinal cord and restoring sensation. Accordingly and in keeping with the overall theme of this special issue, this review focuses narrowly on rodent SCI models for studies of axon regeneration.
Collapse
Affiliation(s)
- Oswald Steward
- Reeve-Irvine Research Center, University of California at Irvine, Irvine, CA 92697, United States; Department of Anatomy & Neurobiology, University of California at Irvine, Irvine, CA 92697, United States; Department of Neurobiology & Behavior, University of California at Irvine, Irvine, CA 92697, United States; Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697, United States; Department of Neurosurgery, University of California at Irvine, Irvine, CA 92697, United States.
| | - Rafer Willenberg
- Reeve-Irvine Research Center, University of California at Irvine, Irvine, CA 92697, United States; Department of Anatomy & Neurobiology, University of California at Irvine, Irvine, CA 92697, United States; University of California at San Diego, School of Medicine, San Diego, CA 92093, United States
| |
Collapse
|
11
|
Pharmacological Suppression of CNS Scarring by Deferoxamine Reduces Lesion Volume and Increases Regeneration in an In Vitro Model for Astroglial-Fibrotic Scarring and in Rat Spinal Cord Injury In Vivo. PLoS One 2015. [PMID: 26222542 PMCID: PMC4519270 DOI: 10.1371/journal.pone.0134371] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Lesion-induced scarring is a major impediment for regeneration of injured axons in the central nervous system (CNS). The collagen-rich glial-fibrous scar contains numerous axon growth inhibitory factors forming a regeneration-barrier for axons. We demonstrated previously that the combination of the iron chelator 2,2’-bipyridine-5,5’-decarboxylic acid (BPY-DCA) and 8-Br-cyclic AMP (cAMP) inhibits scar formation and collagen deposition, leading to enhanced axon regeneration and partial functional recovery after spinal cord injury. While BPY-DCA is not a clinical drug, the clinically approved iron chelator deferoxamine mesylate (DFO) may be a suitable alternative for anti-scarring treatment (AST). In order to prove the scar-suppressing efficacy of DFO we modified a recently published in vitro model for CNS scarring. The model comprises a co-culture system of cerebral astrocytes and meningeal fibroblasts, which form scar-like clusters when stimulated with transforming growth factor-β (TGF-β). We studied the mechanisms of TGF-β-induced CNS scarring and compared the efficiency of different putative pharmacological scar-reducing treatments, including BPY-DCA, DFO and cAMP as well as combinations thereof. We observed modulation of TGF-β-induced scarring at the level of fibroblast proliferation and contraction as well as specific changes in the expression of extracellular matrix molecules and axon growth inhibitory proteins. The individual and combinatorial pharmacological treatments had distinct effects on the cellular and molecular aspects of in vitro scarring. DFO could be identified as a putative anti-scarring treatment for CNS trauma. We subsequently validated this by local application of DFO to a dorsal hemisection in the rat thoracic spinal cord. DFO treatment led to significant reduction of scarring, slightly increased regeneration of corticospinal tract as well as ascending CGRP-positive axons and moderately improved locomotion. We conclude that the in vitro model for CNS scarring is suitable for efficient pre-screening and identification of putative scar-suppressing agents prior to in vivo application and validation, thus saving costs, time and laboratory animals.
Collapse
|
12
|
Le E, Aarabi B, Hersh DS, Shanmuganathan K, Diaz C, Massetti J, Akhtar-Danesh N. Predictors of intramedullary lesion expansion rate on MR images of patients with subaxial spinal cord injury. J Neurosurg Spine 2015; 22:611-21. [DOI: 10.3171/2014.10.spine14576] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
Studies of preclinical spinal cord injury (SCI) in rodents indicate that expansion of intramedullary lesions (IMLs) seen on MR images may be amenable to neuroprotection. In patients with subaxial SCI and motor-complete American Spinal Injury Association (ASIA) Impairment Scale (AIS) Grade A or B, IML expansion has been shown to be approximately 900 μm/hour. In this study, the authors investigated IML expansion in a cohort of patients with subaxial SCI and AIS Grade A, B, C, or D.
METHODS
Seventy-eight patients who had at least 2 MRI scans within 6 days of SCI were enrolled. Data were analyzed by regression analysis.
RESULTS
In this cohort, the mean age was 45.3 years (SD 18.3 years), 73 patients were injured in a motor vehicle crash, from a fall, or in sport activities, and 77% of them were men. The mean Injury Severity Score (ISS) was 26.7 (SD 16.7), and the AIS grade was A in 23 patients, B in 7, C in 7, and D in 41. The mechanism of injury was distraction in 26 patients, compression in 22, disc/osteophyte complex in 29, and Chance fracture in 1. The mean time between injury onset and the first MRI scan (Interval 1) was 10 hours (SD 8.7 hours), and the mean time to the second MRI scan (Interval 2) was 60 hours (SD 29.6 hours). The mean IML lengths of the first and second MR images were 38.8 mm (SD 20.4 mm) and 51 mm (SD 36.5 mm), respectively. The mean time from the first to the second MRI scan (Interval 3) was 49.9 hours (SD 28.4 hours), and the difference in IML lengths was 12.6 mm (SD 20.7 mm), reflecting an expansion rate of 366 μm/ hour (SD 710 μm/hour). IML expansion in patients with AIS Grades A and B was 918 μm/hour (SD 828 μm/hour), and for those with AIS Grades C and D, it was 21 μm/hour (SD 304 μm/hour). Univariate analysis indicated that AIS Grade A or B versus Grades C or D (p < 0.0001), traction (p= 0.0005), injury morphology (p < 0.005), the surgical approach (p= 0.009), vertebral artery injury (p= 0.02), age (p < 0.05), ISS (p < 0.05), ASIA motor score (p < 0.05), and time to decompression (p < 0.05) were all predictors of lesion expansion. In multiple regression analysis, however, the sole determinant of IML expansion was AIS grade (p < 0.005).
CONCLUSIONS
After traumatic subaxial cervical spine or spinal cord injury, patients with motor-complete injury (AIS Grade A or B) had a significantly higher rate of IML expansion than those with motor-incomplete injury (AIS Grade C or D).
Collapse
Affiliation(s)
| | - Bizhan Aarabi
- 1Department of Neurosurgery and
- 2R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland; and
| | | | | | - Cara Diaz
- 2R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Jennifer Massetti
- 2R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Noori Akhtar-Danesh
- 3School of Nursing and Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
Hooshmand MJ, Galvan MD, Partida E, Anderson AJ. Characterization of recovery, repair, and inflammatory processes following contusion spinal cord injury in old female rats: is age a limitation? IMMUNITY & AGEING 2014; 11:15. [PMID: 25512759 PMCID: PMC4265993 DOI: 10.1186/1742-4933-11-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 10/12/2014] [Indexed: 01/14/2023]
Abstract
Background Although the incidence of spinal cord injury (SCI) is steadily rising in the elderly human population, few studies have investigated the effect of age in rodent models. Here, we investigated the effect of age in female rats on spontaneous recovery and repair after SCI. Young (3 months) and aged (18 months) female rats received a moderate contusion SCI at T9. Behavioral recovery was assessed, and immunohistocemical and stereological analyses performed. Results Aged rats demonstrated greater locomotor deficits compared to young, beginning at 7 days post-injury (dpi) and lasting through at least 28 dpi. Unbiased stereological analyses revealed a selective increase in percent lesion area and early (2 dpi) apoptotic cell death caudal to the injury epicenter in aged versus young rats. One potential mechanism for these differences in lesion pathogenesis is the inflammatory response; we therefore assessed humoral and cellular innate immune responses. No differences in either acute or chronic serum complement activity, or acute neutrophil infiltration, were observed between age groups. However, the number of microglia/macrophages present at the injury epicenter was increased by 50% in aged animals versus young. Conclusions These data suggest that age affects recovery of locomotor function, lesion pathology, and microglia/macrophage response following SCI.
Collapse
Affiliation(s)
- Mitra J Hooshmand
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, 2001 Sue and Bill Gross Stem Cell Research, Irvine, CA 92697-4292, USA.,Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
| | - Manuel D Galvan
- Reeve-Irvine Research Center, University of California Irvine, Irvine, CA 92697, USA.,Anatomy and Neurobiology, University of California Irvine, Irvine, CA 92697, USA
| | - Elizabeth Partida
- Reeve-Irvine Research Center, University of California Irvine, Irvine, CA 92697, USA
| | - Aileen J Anderson
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, 2001 Sue and Bill Gross Stem Cell Research, Irvine, CA 92697-4292, USA.,Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA
| |
Collapse
|
15
|
AAVshRNA-mediated suppression of PTEN in adult rats in combination with salmon fibrin administration enables regenerative growth of corticospinal axons and enhances recovery of voluntary motor function after cervical spinal cord injury. J Neurosci 2014; 34:9951-62. [PMID: 25057197 DOI: 10.1523/jneurosci.1996-14.2014] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Conditional genetic deletion of phosphatase and tensin homolog (PTEN) in the sensorimotor cortex of neonatal mice enables regeneration of corticospinal tract (CST) axons after spinal cord injury (SCI). The present study addresses three questions: (1) whether PTEN knockdown in adult rats by nongenetic techniques enables CST regeneration, (2) whether interventions to enable CST regeneration enhance recovery of voluntary motor function, and (3) whether delivery of salmon fibrin into the injury site further enhances CST regeneration and motor recovery. Adult rats were trained in a staircase-reaching task and then received either intracortical injections of AAVshPTEN to delete PTEN or a control vector expressing shRNA for luciferase (AAVshLuc). Rats then received cervical dorsal hemisection injuries and salmon fibrin was injected into the injury site in half the rats, yielding four groups (AAVshPTEN, AAVshLuc, AAVshPTEN + fibrin, and AAVshLuc + fibrin). Forepaw function was assessed for 10 weeks after injury and CST axons were traced by injecting biotin-conjugated dextran amine into the sensorimotor cortex. Rats that received AAVshPTEN alone did not exhibit improved motor function, whereas rats that received AAVshPTEN and salmon fibrin had significantly higher forelimb-reaching scores. Tract tracing revealed that CST axons extended farther caudally in the group that received AAVshPTEN and salmon fibrin versus other groups. There were no significant differences in lesion size between the groups. Together, these data suggest that the combination of PTEN deletion and salmon fibrin injection into the lesion can significantly improve voluntary motor function after SCI by enabling regenerative growth of CST axons.
Collapse
|
16
|
Altinova H, Möllers S, Führmann T, Deumens R, Bozkurt A, Heschel I, Damink LHHO, Schügner F, Weis J, Brook GA. Functional improvement following implantation of a microstructured, type-I collagen scaffold into experimental injuries of the adult rat spinal cord. Brain Res 2014; 1585:37-50. [PMID: 25193604 DOI: 10.1016/j.brainres.2014.08.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 08/10/2014] [Accepted: 08/14/2014] [Indexed: 12/14/2022]
Abstract
The formation of cystic cavitation following severe spinal cord injury (SCI) constitutes one of the major barriers to successful axonal regeneration and tissue repair. The development of bioengineered scaffolds that assist in the bridging of such lesion-induced gaps may contribute to the formulation of combination strategies aimed at promoting functional tissue repair. Our previous in vitro investigations have demonstrated the directed axon regeneration and glial migration supporting properties of microstructured collagen scaffold that had been engineered to possess mechanical properties similar to those of spinal cord tissues. Here, the effect of implanting the longitudinally orientated scaffold into unilateral resection injuries (2mm long) of the mid-cervical lateral funiculus of adult rats has been investigated using behavioural and correlative morphological techniques. The resection injuries caused an immediate and long lasting (up to 12 weeks post injury) deficit of food pellet retrieval by the ipsilateral forepaw. Implantation of the orientated collagen scaffold promoted a significant improvement in pellet retrieval by the ipsilateral forepaw at 6 weeks which continued to improve up to 12 weeks post injury. In contrast, implantation of a non-orientated gelatine scaffold did not result in significant functional improvement. Surprisingly, the improved motor performance was not correlated with the regeneration of lesioned axons through the implanted scaffold. This observation supports the notion that biomaterials may support functional recovery by mechanisms other than simple bridging of the lesion site, such as the local sprouting of injured, or even non-injured fibres.
Collapse
Affiliation(s)
- Haktan Altinova
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Department of Neurosurgery, Evangelic Hospital Bethel, Bielefeld, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany.
| | - Sven Möllers
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; RNL Europe GmbH, Kleinmachnow, Germany
| | - Tobias Führmann
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, ON, Canada
| | - Ronald Deumens
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | - Ahmet Bozkurt
- Department of Plastic Surgery, Reconstructive and Hand Surgery, Burn Centre, Uniklinik Aachen, Aachen, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | | | | | | | - Joachim Weis
- Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | - Gary A Brook
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| |
Collapse
|
17
|
Tzekou A, Fehlings MG. Treatment of spinal cord injury with intravenous immunoglobulin G: preliminary evidence and future perspectives. J Clin Immunol 2014; 34 Suppl 1:S132-8. [PMID: 24722853 PMCID: PMC4050295 DOI: 10.1007/s10875-014-0021-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 03/19/2014] [Indexed: 01/18/2023]
Abstract
Neuroinflammation plays an important role in the secondary pathophysiological mechanisms of spinal cord injury (SCI) and can exacerbate the primary trauma and thus worsen recovery. Although some aspects of the immune response are beneficial, it is thought that leukocyte recruitment and activation in the acute phase of injury results in the production of cytotoxic substances that are harmful to the nervous tissue. Therefore, suppression of excessive inflammation in the spinal cord could serve as a therapeutic strategy to attenuate tissue damage. The immunosuppressant methylprednisolone has been used in the setting of SCI, but there are complications which have attenuated the initial enthusiasm. Hence, there is interest in other immunomodulatory approaches, such as intravenous Immunoglobulin G (IVIg). Importantly, IVIg is used clinically for the treatment of several auto-immune neuropathies, such as Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy (CIPD) and Kawasaki disease, with a good safety profile. Thus, it is a promising treatment candidate for SCI. Indeed, IVIg has been shown by our team to attenuate the immune response and result in improved neurobehavioral recovery following cervical SCI in rats through a mechanism that involves the attenuation of neutrophil recruitment and reduction in the levels of cytokines and cytotoxic enzymes Nguyen et al. (J Neuroinflammation 9:224, 2012). Here we review published data in the context of relevant mechanisms of action that have been proposed for IVIg in other conditions. We hope that this discussion will trigger future research to provide supporting evidence for the efficiency and detailed mechanisms of action of this promising drug in the treatment of SCI, and to facilitate its clinical translation.
Collapse
Affiliation(s)
- Apostolia Tzekou
- Toronto Western Research Institute and Krembil Neuroscience Centre, University Health Network, University of Toronto, Toronto, Canada
| | - Michael G. Fehlings
- Toronto Western Research Institute and Krembil Neuroscience Centre, University Health Network, University of Toronto, Toronto, Canada
- Division of Neurosurgery, Toronto Western Hospital, University Health Network, University of Toronto, 399 Bathurst St. Suite 4WW-449, Toronto, ON M5T2S8 Canada
| |
Collapse
|
18
|
Streijger F, Lee JHT, Duncan GJ, Ng MTL, Assinck P, Bhatnagar T, Plunet WT, Tetzlaff W, Kwon BK. Combinatorial treatment of acute spinal cord injury with ghrelin, ibuprofen, C16, and ketogenic diet does not result in improved histologic or functional outcome. J Neurosci Res 2014; 92:870-83. [PMID: 24658967 DOI: 10.1002/jnr.23372] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/28/2013] [Accepted: 01/20/2014] [Indexed: 11/09/2022]
Abstract
Because of the complex, multifaceted nature of spinal cord injury (SCI), it is widely believed that a combination of approaches will be superior to individual treatments. Therefore, we employed a rat model of cervical SCI to evaluate the combination of four noninvasive treatments that individually have been reported to be effective for acute SCI during clinically relevant therapeutic time windows. These treatments included ghrelin, ibuprofen, C16, and ketogenic diet (KD). These were selected not only because of their previously reported efficacy in SCI models but also for their potentially different mechanisms of action. The administration of ghrelin, ibuprofen, C16, and KD several hours to days postinjury was based on previous observations by others that each treatment had profound effects on the pathophysiology and functional outcome following SCI. Here we showed that, with the exception of a modest improvement in performance on the Montoya staircase test at 8-10 weeks postinjury, the combinatorial treatment with ghrelin, ibuprofen, C16, and KD did not result in any significant improvements in the rearing test, grooming test, or horizontal ladder. Histologic analysis of the spinal cords did not reveal any significant differences in tissue sparing between treatment and control groups. Although single approaches of ghrelin, ibuprofen, C16, and KD have been reported to be beneficial after SCI, our results show that the combination of the four interventions did not confer significant functional or histological improvements in a cervical model of SCI. Possible interactions among the treatments may have negated their beneficial effects, emphasizing the challenges that have to be addressed when considering combinatorial drug therapies for SCI.
Collapse
Affiliation(s)
- F Streijger
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada; Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Warren PM, Alilain WJ. The challenges of respiratory motor system recovery following cervical spinal cord injury. PROGRESS IN BRAIN RESEARCH 2014; 212:173-220. [DOI: 10.1016/b978-0-444-63488-7.00010-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
20
|
Abstract
TRPM4 is a Ca(2+)-activated nonselective cation channel. The channel is activated by an increase of intracellular Ca(2+) and is regulated by several factors including temperature and Pi(4,5)P2. TRPM4 allows Na(+) entry into the cell upon activation, but is completely impermeable to Ca(2+). Unlike TRPM5, its closest relative in the transient receptor potential family, TRPM4 proteins are widely expressed in the body. Currents with properties that are reminiscent of TRPM4 have been described in a variety of tissues since the advent of the patch clamp technology, but their physiological role is only beginning to be clarified with the increasing characterization of knockout mouse models for TRPM4. Furthermore, mutations in the TRPM4 gene have been associated with cardiac conduction disorders in human patients. This review aims to overview the currently available data on the functional properties of TRPM4 and the current understanding of its physiological role in healthy and diseased tissue.
Collapse
Affiliation(s)
- Ilka Mathar
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Herestraat 49, bus 802, 3000, Leuven, Belgium
| | | | | | | | | | | |
Collapse
|
21
|
Simard JM, Popovich PG, Tsymbalyuk O, Caridi J, Gullapalli RP, Kilbourne MJ, Gerzanich V. MRI evidence that glibenclamide reduces acute lesion expansion in a rat model of spinal cord injury. Spinal Cord 2013; 51:823-7. [PMID: 24042989 PMCID: PMC4076111 DOI: 10.1038/sc.2013.99] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 08/01/2013] [Accepted: 08/02/2013] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Experimental, controlled, animal study. OBJECTIVES To use non-invasive magnetic resonance imaging (MRI) to corroborate invasive studies showing progressive expansion of a hemorrhagic lesion during the early hours after spinal cord trauma and to assess the effect of glibenclamide, which blocks Sur1-Trpm4 channels implicated in post-traumatic capillary fragmentation, on lesion expansion. SETTING Baltimore. METHODS Adult female Long-Evans rats underwent unilateral impact trauma to the spinal cord at C7, which produced ipsilateral but not contralateral primary hemorrhage. In series 1 (six control rats and six administered glibenclamide), hemorrhagic lesion expansion was characterized using MRI at 1 and 24 h after trauma. In series 2, hemorrhagic lesion size was characterized on coronal tissue sections at 15 min (eight rats) and at 24 h after trauma (eight control rats and eight administered glibenclamide). RESULTS MRI (T2 hypodensity) showed that lesions expanded 2.3±0.33-fold (P<0.001) during the first 24 h in control rats, but only 1.2±0.07-fold (P>0.05) in glibenclamide-treated rats. Measuring the areas of hemorrhagic contusion on tissue sections at the epicenter showed that lesions expanded 2.2±0.12-fold (P<0.001) during the first 24 h in control rats, but only 1.1±0.05-fold (P>0.05) in glibenclamide-treated rats. Glibenclamide treatment was associated with significantly better neurological function (unilateral BBB scores) at 24 h in both the ipsilateral (median scores, 9 vs 0; P<0.001) and contralateral (median scores, 12 vs 2; P<0.001) hindlimbs. CONCLUSION MRI is an accurate non-invasive imaging biomarker of lesion expansion and is a sensitive measure of the ability of glibenclamide to reduce lesion expansion.
Collapse
Affiliation(s)
- JM Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore MD, USA
| | - PG Popovich
- Center for Brain and Spinal Cord Repair and Department of Neuroscience, The Ohio State University College of Medicine, Columbus, OH, USA
| | - O Tsymbalyuk
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - J Caridi
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - RP Gullapalli
- Department of Radiology, University of Maryland School of Medicine, Baltimore MD, USA
| | - MJ Kilbourne
- Department of Surgery, Walter Reed Army Medical Center, Washington, DC, USA
| | - V Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
22
|
Young F, Sloan A, Song B. Dental pulp stem cells and their potential roles in central nervous system regeneration and repair. J Neurosci Res 2013; 91:1383-93. [PMID: 23996516 DOI: 10.1002/jnr.23250] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/12/2013] [Accepted: 04/15/2013] [Indexed: 12/12/2022]
Abstract
Functional recovery from injuries to the brain or spinal cord represents a major clinical challenge. The transplantation of stem cells, traditionally isolated from embryonic tissue, may help to reduce damage following such events and promote regeneration and repair through both direct cell replacement and neurotrophic mechanisms. However, the therapeutic potential of using embryonic stem/progenitor cells is significantly restricted by the availability of embryonic tissues and associated ethical issues. Populations of stem cells reside within the dental pulp, representing an alternative source of cells that can be isolated with minimal invasiveness, and thus should illicit fewer moral objections, as a replacement for embryonic/fetal-derived stem cells. Here we discuss the similarities between dental pulp stem cells (DPSCs) and the endogenous stem cells of the central nervous system (CNS) and their ability to differentiate into neuronal cell types. We also consider in vitro and in vivo studies demonstrating the ability of DPSCs to help protect against and repair neuronal damage, suggesting that dental pulp may provide a viable alternative source of stem cells for replacement therapy following CNS damage.
Collapse
Affiliation(s)
- Fraser Young
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff, United Kingdom
| | | | | |
Collapse
|
23
|
Genome-wide gene expression profiling of stress response in a spinal cord clip compression injury model. BMC Genomics 2013; 14:583. [PMID: 23984903 PMCID: PMC3846681 DOI: 10.1186/1471-2164-14-583] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 08/13/2013] [Indexed: 12/23/2022] Open
Abstract
Background The aneurysm clip impact-compression model of spinal cord injury (SCI) is a standard injury model in animals that closely mimics the primary mechanism of most human injuries: acute impact and persisting compression. Its histo-pathological and behavioural outcomes are extensively similar to human SCI. To understand the distinct molecular events underlying this injury model we analyzed global mRNA abundance changes during the acute, subacute and chronic stages of a moderate to severe injury to the rat spinal cord. Results Time-series expression analyses resulted in clustering of the majority of deregulated transcripts into eight statistically significant expression profiles. Systematic application of Gene Ontology (GO) enrichment pathway analysis allowed inference of biological processes participating in SCI pathology. Temporal analysis identified events specific to and common between acute, subacute and chronic time-points. Processes common to all phases of injury include blood coagulation, cellular extravasation, leukocyte cell-cell adhesion, the integrin-mediated signaling pathway, cytokine production and secretion, neutrophil chemotaxis, phagocytosis, response to hypoxia and reactive oxygen species, angiogenesis, apoptosis, inflammatory processes and ossification. Importantly, various elements of adaptive and induced innate immune responses span, not only the acute and subacute phases, but also persist throughout the chronic phase of SCI. Induced innate responses, such as Toll-like receptor signaling, are more active during the acute phase but persist throughout the chronic phase. However, adaptive immune response processes such as B and T cell activation, proliferation, and migration, T cell differentiation, B and T cell receptor-mediated signaling, and B cell- and immunoglobulin-mediated immune response become more significant during the chronic phase. Conclusions This analysis showed that, surprisingly, the diverse series of molecular events that occur in the acute and subacute stages persist into the chronic stage of SCI. The strong agreement between our results and previous findings suggest that our analytical approach will be useful in revealing other biological processes and genes contributing to SCI pathology.
Collapse
|
24
|
Muradov JM, Hagg T. Intravenous infusion of magnesium chloride improves epicenter blood flow during the acute stage of contusive spinal cord injury in rats. J Neurotrauma 2013; 30:840-52. [PMID: 23302047 PMCID: PMC3660110 DOI: 10.1089/neu.2012.2670] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Vasospasm, hemorrhage, and loss of microvessels at the site of contusive or compressive spinal cord injury lead to infarction and initiate secondary degeneration. Here, we used intravenous injection of endothelial-binding lectin followed by histology to show that the number of perfused microvessels at the injury site is decreased by 80-90% as early as 20 min following a moderate T9 contusion in adult female rats. Hemorrhage within the spinal cord also was maximal at 20 min, consistent with its vasoconstrictive actions in the central nervous system (CNS). Microvascular blood flow recovered to up to 50% of normal volume in the injury penumbra by 6 h, but not at the epicenter. A comparison with an endothelial cell marker suggested that many microvessels fail to be reperfused up to 48 h post-injury. The ischemia was probably caused by vasospasm of vessels penetrating the parenchyma, because repeated Doppler measurements over the spinal cord showed a doubling of total blood flow over the first 12 h. Moreover, intravenous infusion of magnesium chloride, used clinically to treat CNS vasospasm, greatly improved the number of perfused microvessels at 24 and 48 h. The magnesium treatment seemed safe as it did not increase hemorrhage, despite the improved parenchymal blood flow. However, the treatment did not reduce acute microvessel, motor neuron or oligodendrocyte loss, and when infused for 7 days did not affect functional recovery or spared epicenter white matter over a 4 week period. These data suggest that microvascular blood flow can be restored with a clinically relevant treatment following spinal cord injury.
Collapse
Affiliation(s)
- Johongir M. Muradov
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - Theo Hagg
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky
| |
Collapse
|
25
|
Simard JM, Woo SK, Aarabi B, Gerzanich V. The Sur1-Trpm4 Channel in Spinal Cord Injury. ACTA ACUST UNITED AC 2013; Suppl 4. [PMID: 24834370 DOI: 10.4172/2165-7939.s4-002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spinal cord injury (SCI) is a major unsolved challenge in medicine. Impact trauma to the spinal cord shears blood vessels, causing an immediate 'primary hemorrhage'. During the hours following trauma, the region of hemorrhage enlarges progressively, with delayed or 'secondary hemorrhage' adding to the primary hemorrhage, and effectively doubling its volume. The process responsible for the secondary hemorrhage that results in early expansion of the hemorrhagic lesion is termed 'progressive hemorrhagic necrosis' (PHN). PHN is a dynamic process of auto destruction whose molecular underpinnings are only now beginning to be elucidated. PHN results from the delayed, progressive, catastrophic failure of the structural integrity of capillaries. The resulting 'capillary fragmentation' is a unique, pathognomonic feature of PHN. Recent work has implicated the Sur1-Trpm4 channel that is newly upregulated in penumbral microvessels as being required for the development of PHN. Targeting the Sur1-Trpm4 channel by gene deletion, gene suppression, or pharmacological inhibition of either of the two channel subunits, Sur1 or Trpm4, yields exactly the same effects histologically and functionally, and exactly the same unique, pathognomonic phenotype - the prevention of capillary fragmentation. The potential advantage of inhibiting Sur1-Trpm4 channels using glibenclamide is a highly promising strategy for ameliorating the devastating sequelae of spinal cord trauma in humans.
Collapse
Affiliation(s)
- J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA ; Department of Pathology, University of Maryland School of Medicine, Baltimore, USA ; Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
| | - Seung Kyoon Woo
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Bizhan Aarabi
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| |
Collapse
|
26
|
Aarabi B, Simard JM, Kufera JA, Alexander M, Zacherl KM, Mirvis SE, Shanmuganathan K, Schwartzbauer G, Maulucci CM, Slavin J, Ali K, Massetti J, Eisenberg HM. Intramedullary lesion expansion on magnetic resonance imaging in patients with motor complete cervical spinal cord injury. J Neurosurg Spine 2012; 17:243-50. [PMID: 22794535 PMCID: PMC3534760 DOI: 10.3171/2012.6.spine12122] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECT The authors performed a study to determine if lesion expansion occurs in humans during the early hours after spinal cord injury (SCI), as has been established in rodent models of SCI, and to identify factors that might predict lesion expansion. METHODS The authors studied 42 patients with acute cervical SCI and admission American Spinal Injury Association Impairment Scale Grades A (35 patients) and B (7 patients) in whom 2 consecutive MRI scans were obtained 3-134 hours after trauma. They recorded demographic data, clinical information, Injury Severity Score (ISS), admission MRI-documented spinal canal and cord characteristics, and management strategies. RESULTS The characteristics of the cohort were as follows: male/female ratio 37:5; mean age, 34.6 years; and cause of injury, motor vehicle collision, falls, and sport injuries in 40 of 42 cases. The first MRI study was performed 6.8 ±2.7 hours (mean ± SD) after injury, and the second was performed 54.5 ± 32.3 hours after injury. The rostrocaudal intramedullary length of the lesion on the first MRI scan was 59.2 ± 16.1 mm, whereas its length on the second was 88.5 ± 31.9 mm. The principal factors associated with lesion length on the first MRI study were the time between injury and imaging (p = 0.05) and the time to decompression (p = 0.03). The lesion's rate of rostrocaudal intramedullary expansion in the interval between the first and second MRI was 0.9 ± 0.8 mm/hour. The principal factors associated with the rate of expansion were the maximum spinal cord compression (p = 0.03) and the mechanism of injury (p = 0.05). CONCLUSIONS Spinal cord injury in humans is characterized by lesion expansion during the hours following trauma. Lesion expansion has a positive relationship with spinal cord compression and may be mitigated by early surgical decompression. Lesion expansion may be a novel surrogate measure by which to assess therapeutic effects in surgical or drug trials.
Collapse
Affiliation(s)
- Bizhan Aarabi
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Simard JM, Popovich PG, Tsymbalyuk O, Gerzanich V. Spinal cord injury with unilateral versus bilateral primary hemorrhage--effects of glibenclamide. Exp Neurol 2012; 233:829-35. [PMID: 22197047 PMCID: PMC3272086 DOI: 10.1016/j.expneurol.2011.11.048] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 10/12/2011] [Accepted: 11/29/2011] [Indexed: 11/21/2022]
Abstract
In spinal cord injury (SCI), block of Sur1-regulated NC(Ca-ATP) channels by glibenclamide protects penumbral capillaries from delayed fragmentation, resulting in reduced secondary hemorrhage, smaller lesions and better neurological function. All published experiments demonstrating a beneficial effect of glibenclamide in rat models of SCI have used a cervical hemicord impact calibrated to produce primary hemorrhage located exclusively ipsilateral to the site of impact. Here, we tested the hypothesis that glibenclamide also would be protective in a model with more extensive, bilateral primary hemorrhage. We studied the effect of glibenclamide in 2 rat cervical hemicord contusion models with identical impact force (10 g, 25 mm), one with the impactor positioned laterally to yield unilateral primary hemorrhage (UPH), and the other with the impactor positioned more medially, yielding larger, bilateral primary hemorrhages (BPH) and 6-week lesion volumes that were 45% larger. Functional outcome measures included: modified (unilateral) Basso, Beattie, and Bresnahan scores, angled plane performance, and rearing times. In the UPH model, the effects of glibenclamide were similar to previous observations, including a functional benefit as early as 24h after injury and 6-week lesion volumes that were 57% smaller than controls. In the BPH model, glibenclamide exerted a significant benefit over controls, but the functional benefit was smaller than in the UPH model and 6-week lesion volumes were 33% smaller than controls. We conclude that glibenclamide is beneficial in different models of cervical SCI, with the magnitude of the benefit depending on the magnitude and extent of primary hemorrhage.
Collapse
Affiliation(s)
- J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | | | | | | |
Collapse
|
28
|
Chew DJ, Fawcett JW, Andrews MR. The challenges of long-distance axon regeneration in the injured CNS. PROGRESS IN BRAIN RESEARCH 2012. [PMID: 23186719 DOI: 10.1016/b978-0-444-59544-7.00013-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Injury to the central nervous system (CNS) that results in long-tract axonal damage typically leads to permanent functional deficits in areas innervated at, and below, the level of the lesion. The initial ischemia, inflammation, and neurodegeneration are followed by a progressive generation of scar tissue, dieback of transected axons, and demyelination, creating an area inhibitory to regrowth and recovery. Two ways to combat this inhibition is to therapeutically target the extrinsic and intrinsic properties of the axon-scar environment. Scar tissue within and surrounding the lesion site can be broken down using an enzyme known as chondroitinase. Negative regulators of adult neuronal growth, such as Nogo, can be neutralized with antibodies. Both therapies greatly improve functional recovery in animal models. Alternatively, modifying the intrinsic growth properties of CNS neurons through gene therapy or pharmacotherapy has also shown promising axonal regeneration after injury. Despite these promising therapies, the main challenge of long-distance axon regeneration still remains; achieving a level of functional and organized connectivity below the level of the lesion that mimics the intact CNS.
Collapse
Affiliation(s)
- Daniel J Chew
- Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK
| | | | | |
Collapse
|
29
|
Vascular Pathology as a Potential Therapeutic Target in SCI. Transl Stroke Res 2011; 2:556-74. [PMID: 24323683 DOI: 10.1007/s12975-011-0128-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/21/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
Abstract
Acute traumatic spinal cord injury (SCI) is characterized by a progressive secondary degeneration which exacerbates the loss of penumbral tissue and neurological function. Here, we first provide an overview of the known pathophysiological mechanisms involving injured microvasculature and molecular regulators that contribute to the loss and dysfunction of existing and new blood vessels. We also highlight the differences between traumatic and ischemic injuries which may yield clues as to the more devastating nature of traumatic injuries, possibly involving toxicity associated with hemorrhage. We also discuss known species differences with implications for choosing models, their relevance and utility to translate new treatments towards the clinic. Throughout this review, we highlight the potential opportunities and proof-of-concept experimental studies for targeting therapies to endothelial cell-specific responses. Lastly, we comment on the need for vascular mechanisms to be included in drug development and non-invasive diagnostics such as serum and cerebrospinal fluid biomarkers and imaging of spinal cord pathology.
Collapse
|
30
|
Walsh JT, Kipnis J. Regulatory T cells in CNS injury: the simple, the complex and the confused. Trends Mol Med 2011; 17:541-7. [PMID: 21741881 DOI: 10.1016/j.molmed.2011.05.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 05/21/2011] [Accepted: 05/27/2011] [Indexed: 11/19/2022]
Abstract
Regulatory CD4(+)CD25(+)Foxp3(+) T cells (Tregs) have been the focus of significant attention for their role in controlling immune responses. Although knowledge of Treg biology has burgeoned, wide gaps remain in our understanding of Treg function under both normal and pathological conditions. Pioneering studies demonstrated roles for Tregs in cancer and autoimmune diseases, including experimental autoimmune encephalitis, and this knowledge is often applied to other pathologies including neurodegenerative conditions. However, differences between immunity in neurodegeneration and in malignancy or autoimmunity are often neglected. Thus, Treg manipulations in central nervous system (CNS) neurodegenerative conditions often yield unexpected outcomes. In this piece, we explore how the immunology of neurodegeneration differs from that of cancer and autoimmunity and how these differences create confusion about the role of Tregs in neurodegenerative conditions.
Collapse
Affiliation(s)
- James T Walsh
- Neuroscience Graduate Program and Medical Scientist Training Program, Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
| | | |
Collapse
|
31
|
Abstract
Spinal cord injury (SCI) is characterized by secondary degeneration, which leads to tissue loss at the epicenter and subsequent functional deficits. This review provides insight into the pathophysiology of microvascular dysfunction and endothelial cell loss, which are among the earliest responses during the first postinjury day. The enigmatic role of the angiogenic response in the penumbra around the lost tissue, which occurs during the first 2 weeks, is also discussed. The importance of stabilizing and rescuing the injured vasculature is now well-recognized, and several pharmacological and genetic treatments have emerged in the past few years. We conclude with suggestions for future experimental research, including development of vascular-selective treatments and exploitation of genetic models. In summary, vascular dysfunction following SCI is an important contributor to neurological deficits, as proposed long ago. However, there now appears to be new and potentially powerful opportunities for treating acute SCI by targeting the vascular responses.
Collapse
Affiliation(s)
- Janelle M. Fassbender
- Kentucky Spinal Cord Injury Research Center, School of Medicine, University of Louisville, Louisville, KY 40292 USA
- M.D./Ph.D. Program, Louisville, KY 40292 USA
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY 40292 USA
| | - Scott R. Whittemore
- Kentucky Spinal Cord Injury Research Center, School of Medicine, University of Louisville, Louisville, KY 40292 USA
- Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY 40292 USA
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY 40292 USA
| | - Theo Hagg
- Kentucky Spinal Cord Injury Research Center, School of Medicine, University of Louisville, Louisville, KY 40292 USA
- Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY 40292 USA
- Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, Louisville, KY 40292 USA
| |
Collapse
|
32
|
Fassbender JM, Myers SA, Whittemore SR. Activating Notch signaling post-SCI modulates angiogenesis in penumbral vascular beds but does not improve hindlimb locomotor recovery. Exp Neurol 2010; 227:302-13. [PMID: 21156172 DOI: 10.1016/j.expneurol.2010.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Revised: 11/02/2010] [Accepted: 12/03/2010] [Indexed: 01/23/2023]
Abstract
Manipulation of Notch signaling has led to significant tumor shrinkage as well as recovery from several traumatic and ischemic injury models indicating its potential clinical application. We have tested both an agonist and antagonist of Notch signaling to study the effects of Notch-mediated angiogenesis on spinal cord vascular pathology following traumatic injury. Initial neonatal retinal vascularization assays showed their respective bioactivities in vivo. Mice were treated with either the antagonist Jagged1-Fc chimera (Jag1-Fc) or agonist Notch1 antibody (N1 Ab) immediately following a mid-thoracic contusive injury through an initial jugular bolus and tail vein injections for 3 days post-injury. After 14 days, activating Notch signaling decreased the overall vascular density within the penumbral gray matter compared to controls while maintaining the density of perfused vessels. Inhibiting Notch signaling did not change the density or perfusion of microvessels within the lesion penumbra. Furthermore, neither activation nor inhibition of Notch signaling significantly altered inflammation, hypoxia, and lesion volume in the epicenter and penumbra. Importantly, neither treatment changed locomotor function. In postnatal retinal vascular assays, administration of Jag1-Fc and N1 Ab increased and decreased both tip cell numbers and branch points in each treatment, respectively. However, these agents did not modulate primary CNS EC proliferation in vitro in spite of sufficient Notch ligand expression. We conclude that Notch signaling, while an important part of developmental angiogenesis, may play a lesser role in mediating vascular recovery following traumatic injury to the CNS.
Collapse
|
33
|
Hui SP, Dutta A, Ghosh S. Cellular response after crush injury in adult zebrafish spinal cord. Dev Dyn 2010; 239:2962-79. [DOI: 10.1002/dvdy.22438] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
34
|
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.
Collapse
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.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Kurihara D, Ueno M, Tanaka T, Yamashita T. Expression of galectin-1 in immune cells and glial cells after spinal cord injury. Neurosci Res 2010; 66:265-70. [DOI: 10.1016/j.neures.2009.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 11/17/2009] [Accepted: 11/18/2009] [Indexed: 10/20/2022]
|
36
|
Akhtar AZ, Pippin JJ, Sandusky CB. Animal studies in spinal cord injury: a systematic review of methylprednisolone. Altern Lab Anim 2009; 37:43-62. [PMID: 19292575 DOI: 10.1177/026119290903700108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The objective of this study was to examine whether animal studies can reliably be used to determine the usefulness of methylprednisolone (MP) and other treatments for acute spinal cord injury (SCI) in humans. This was achieved by performing a systematic review of animal studies on the effects of MP administration on the functional outcome of acute SCI. Data were extracted from the published articles relating to: outcome; MP dosing regimen; species/strain; number of animals; methodological quality; type of injury induction; use of anaesthesia; functional scale used; and duration of follow-up. Subgroup analyses were performed, based on species or strain, injury method, MP dosing regimen, functional outcome measured, and methodological quality. Sixty-two studies were included, which involved a wide variety of animal species and strains. Overall, beneficial effects of MP administration were obtained in 34% of the studies, no effects in 58%, and mixed results in 8%. The results were inconsistent both among and within species, even when attempts were made to detect any patterns in the results through subgroup analyses. The results of this study demonstrate the barriers to the accurate prediction from animal studies of the effectiveness of MP in the treatment of acute SCI in humans. This underscores the need for the development and implementation of validated testing methods.
Collapse
Affiliation(s)
- Aysha Z Akhtar
- Physicians Committee for Responsible Medicine, Washington, DC, USA.
| | | | | |
Collapse
|
37
|
Gerzanich V, Woo SK, Vennekens R, Tsymbalyuk O, Ivanova S, Ivanov A, Geng Z, Chen Z, Nilius B, Flockerzi V, Freichel M, Simard JM. De novo expression of Trpm4 initiates secondary hemorrhage in spinal cord injury. Nat Med 2009; 15:185-91. [PMID: 19169264 DOI: 10.1038/nm.1899] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 11/26/2008] [Indexed: 12/14/2022]
Abstract
The role of transient receptor potential M4 (Trpm4), an unusual member of the Trp family of ion channels, is poorly understood. Using rodent models of spinal cord injury, we studied involvement of Trpm4 in the progressive expansion of secondary hemorrhage associated with capillary fragmentation, the most destructive mechanism of secondary injury in the central nervous system. Trpm4 mRNA and protein were abundantly upregulated in capillaries preceding their fragmentation and formation of petechial hemorrhages. Trpm4 expression in vitro rendered COS-7 cells highly susceptible to oncotic swelling and oncotic death following ATP depletion. After spinal cord injury, in vivo gene suppression in rats treated with Trpm4 antisense or in Trpm4(-/-) mice preserved capillary structural integrity, eliminated secondary hemorrhage, yielded a threefold to fivefold reduction in lesion volume and produced a substantial improvement in neurological function. To our knowledge, this is the first example of a Trp channel that must undergo de novo expression for manifestation of central nervous system pathology.
Collapse
Affiliation(s)
- Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, 22 South Greene Street, Suite S12D, Baltimore, Maryland 21201-1595, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Multiple neuroprotective agents have shown benefit for the treatment of acute spinal cord injury (SCI) in animal studies. However, clinical trials have, thus far, been uniformly disappointing. This review explores reasons for discrepancies between promising animal studies and disappointing clinical trials and potential barriers to extrapolation of research results from animals to humans. The three major barriers disclosed are: differences in injury type between laboratory-induced SCI and clinical SCI, difficulties in interpreting functional outcome in animals, and inter-species and interstrain differences in pathophysiology of SCI. These barriers can impair the effectiveness of animal models of SCI to predict human outcomes. While some of these barriers can be overcome, others are inherent to the animal models.
Collapse
Affiliation(s)
- Aysha Z Akhtar
- Physicians Committee for Responsible Medicine, Washington, D.C. 20016, USA.
| | | | | |
Collapse
|
39
|
Manitt C, Wang D, Kennedy TE, Howland DR. Positioned to inhibit: netrin-1 and netrin receptor expression after spinal cord injury. J Neurosci Res 2007; 84:1808-20. [PMID: 16998900 DOI: 10.1002/jnr.21070] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Netrin-1 regulates axon extension during embryonic development and is expressed by neurons and myelinating oligodendrocytes in the adult CNS. To investigate the potential role of netrin-1 after spinal cord injury, we examined the expression of netrin-1 and netrin receptors after sagittal myelotomy in adult rats. This lesion targets spinal commissural projections, which respond to netrin-1 during development. Netrin-1 mRNA and protein levels were dramatically reduced at the site of injury and reduced expression persisted for at least 7 months. Neither netrin-1 protein nor mRNA was associated with the glial scar, but netrin-1 was expressed by neurons and oligodendrocytes immediately adjacent to the lesion. The post-injury distribution detected is similar to that reported for myelin-associated inhibitors of axon regeneration, such as Nogo, and is distinct from the distribution of inhibitors associated with a glial scar. DCC and UNC-5 homologue (UNC5H) expression also was reduced after injury. Although UNC5H levels recovered, DCC expression at the site of injury remained approximately 50% of pre-injury values at 7 months. Increased UNC5H immunoreactivity was associated with fibers in the superficial layers of the dorsal horn and in fibers located in white matter adjacent to the lesion. The dominant expression of UNC5H on axons and neurons in the spinal cord after injury and the persistent expression of netrin-1 by oligodendrocytes surrounding the lesion are consistent with the hypothesis that netrin-1 is a myelin-associated inhibitor of axonal regeneration after spinal cord injury.
Collapse
Affiliation(s)
- Colleen Manitt
- Centre for Neuronal Survival, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | | | | | | |
Collapse
|
40
|
Nossin-Manor R, Duvdevani R, Cohen Y. Spatial And Temporal Damage Evolution after Hemi-Crush Injury in Rat Spinal Cord Obtained by High b-Value q-Space Diffusion Magnetic Resonance Imaging. J Neurotrauma 2007; 24:481-91. [PMID: 17402854 DOI: 10.1089/neu.2006.0158] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spinal cord injury (SCI) is a major cause of disability for many living persons. Therefore, several experimental models and handful of techniques were developed to study and characterize the damage evolution following SCI. In the present study, high b-value q-space diffusion-weighted imaging (DWI) was used to follow the spatial and temporal damage evolution in excised rat spinal cords following hemi-crush injury. The DWI results were correlated with behavioral testing. It was found that the damage depends, as expected, on the severity of the insult. Significant spontaneous recovery was observed, six weeks following the insult, only for the mild hemi-crush injury but not following the severe injury. The damage was found to be more severe in the area caudal to the trauma site as compared to the rostral section of the cord.
Collapse
Affiliation(s)
- Revital Nossin-Manor
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | | | | |
Collapse
|
41
|
Hannila SS, Siddiq MM, Filbin MT. Therapeutic Approaches to Promoting Axonal Regeneration in the Adult Mammalian Spinal Cord. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 77:57-105. [PMID: 17178472 DOI: 10.1016/s0074-7742(06)77003-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Sari S Hannila
- Department of Biological Sciences, Hunter College, City University of New York, New York 10021, USA
| | | | | |
Collapse
|
42
|
Gomes-Leal W, Corkill DJ, Picanço-Diniz CW. Systematic analysis of axonal damage and inflammatory response in different white matter tracts of acutely injured rat spinal cord. Brain Res 2005; 1066:57-70. [PMID: 16325784 DOI: 10.1016/j.brainres.2005.10.069] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 10/05/2005] [Accepted: 10/11/2005] [Indexed: 10/25/2022]
Abstract
The mechanisms of white matter (WM) damage during secondary degeneration are a fundamental issue in the pathophysiology of central nervous system (CNS) diseases. Our main goal was to describe the pattern of an acute inflammatory response and secondary damage to axons in different WM tracts of acutely injured rat spinal cord. Adult rats were deeply anesthetized and injected with 20 nmol of NMDA into the spinal cord ventral horn on T7. Animals were perfused after survival times of 1 day, 3 days and 7 days. Ten micrometer sections were submitted to immunocytochemical analysis for activated macrophages/microglia, neutrophils and damaged axons. There were inflammatory response and progressive tissue destruction of ventral WM (VWM) with formation of microcysts in both VWM and lateral WM (LWM). In the VWM, the number of beta-amyloid precursor protein (beta-APP) end-bulbs increased from 1 day with a peak at 3 days, decreasing by 7 days following the injection. APP end-bulbs were present in the dorsal WM (DWM) at 3 days survival time but were not in the LWM. Electron microscopic analysis revealed different degrees of myelin disruption and axonal pathology in the vacuolated WM up to 14 mm along the rostrocaudal axis. Quantitative analysis revealed a significant loss of medium and large axons (P < 0.05), but not of small axons (P > 0.05). Our results suggest that bystander axonal damage and myelin vacuolation are important secondary component of the pathology of WM tracts following rat SCI. Further studies are needed to understand the mechanisms of these pathological events.
Collapse
Affiliation(s)
- W Gomes-Leal
- Laboratório de Neuroanatomia Funcional, Departamento de Morfologia, Centro de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa S/N, Campus do Guamá, CEP:66075-900. Belém-Pará, Brasil.
| | | | | |
Collapse
|
43
|
Fujiki M, Furukawa Y, Kobayashi H, Abe T, Ishii K, Uchida S, Kamida T. Geranylgeranylacetone limits secondary injury, neuronal death, and progressive necrosis and cavitation after spinal cord injury. Brain Res 2005; 1053:175-84. [PMID: 16054120 DOI: 10.1016/j.brainres.2005.06.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2005] [Revised: 06/16/2005] [Accepted: 06/17/2005] [Indexed: 11/15/2022]
Abstract
This study evaluates the neuroprotective effects of geranylgeranylacetone (GGA), which is known as an antiulcer agent and more recently as a heat-shock and other neuroprotective protein inducer, on secondary degeneration after spinal cord injury in rats. Crush injuries were produced at the T8 level using an extradural approach. Optimal administration conditions of GGA were established in an initial experiment by evaluating the appearance of lesions 24 h after injury in sections stained with H-E. Then, in a second experiment, animals treated with the optimal condition (600 mg/kg, 24 h before injury and thereafter every 24 h) were allowed to survive for 6 and 24 h and 1, 3, and 8 weeks after injury, and spinal cords were prepared for histological evaluation by staining for H-E for general histopathology and by silver staining for axons. There was a significant reduction (46%) in lesion volume 24 h after injury in animals treated with optimal administration conditions. The increase in tumor necrosis factor-alpha (TNF-alpha) and the accumulation of neutrophils in the damaged segment of the spinal cord 4 h after injury were significantly inhibited in animals that received GGA. Lesion size and cavitation area remained smaller in treated animals throughout the post-injury survival interval. These results suggest that GGA administration significantly reduces the secondary degeneration that would otherwise occur. The mechanism by which GGA exerts its beneficial effect is unknown but may involve reduction of TNF-alpha activation at the injured cord and/or inhibition of inflammation.
Collapse
Affiliation(s)
- Minoru Fujiki
- Department of Neurosurgery, School of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Oita 879-5593, Japan.
| | | | | | | | | | | | | |
Collapse
|
44
|
Adalbert R, Gillingwater TH, Haley JE, Bridge K, Beirowski B, Berek L, Wagner D, Grumme D, Thomson D, Celik A, Addicks K, Ribchester RR, Coleman MP. A rat model of slow Wallerian degeneration (WldS) with improved preservation of neuromuscular synapses. Eur J Neurosci 2005; 21:271-7. [PMID: 15654865 DOI: 10.1111/j.1460-9568.2004.03833.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The slow Wallerian degeneration phenotype, Wld(S), which delays Wallerian degeneration and axon pathology for several weeks, has so far been studied only in mice. A rat model would have several advantages. First, rats model some human disorders better than mice. Second, the larger body size of rats facilitates more complex surgical manipulations. Third, rats provide a greater yield of tissue for primary culture and biochemical investigations. We generated transgenic Wld(S) rats expressing the Ube4b/Nmnat1 chimeric gene in the central and peripheral nervous system. As in Wld(S) mice, their axons survive up to 3 weeks after transection and remain functional for at least 1 week. Protection of axotomized nerve terminals is stronger than in mice, particularly in one line, where 95-100% of neuromuscular junctions remained intact and functional after 5 days. Furthermore, the loss of synaptic phenotype with age was much less in rats than in mice. Thus, the slow Wallerian degeneration phenotype can be transferred to another mammalian species and synapses may be more effectively preserved after axotomy in species with longer axons.
Collapse
|
45
|
Dusart I, Ghoumari A, Wehrle R, Morel MP, Bouslama-Oueghlani L, Camand E, Sotelo C. Cell death and axon regeneration of Purkinje cells after axotomy: challenges of classical hypotheses of axon regeneration. ACTA ACUST UNITED AC 2005; 49:300-16. [PMID: 16111558 DOI: 10.1016/j.brainresrev.2004.11.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 11/16/2004] [Accepted: 11/24/2004] [Indexed: 12/11/2022]
Abstract
Although adult mammalian neurons are able to regenerate their axons in the peripheral nervous system under certain conditions, they are not able to do it in the central nervous system. The environment surrounding the severed axons appears to be a key factor for axon regeneration. Many studies aiming to enhance axon regeneration in the CNS of adult mammals have successfully manipulated this environment by adding growth permissive molecules and/or neutralizing growth inhibitory molecules. In both cases, the number of axons able to regenerate was low and the different neuronal populations were not equal in their regenerative response, suggesting that manipulation of the environment is not always sufficient. This is particularly well illustrated in the cerebellar system, in which axotomized inferior olivary neurons regenerate when confronted with a permissive environment, whereas mature Purkinje cells do not. The intrinsic ability of a neuron to regenerate its axon is generally correlated with the intensity of its reaction to axotomy (expression of molecules, probability to die). Furthermore, molecules such as GAP-43 (growth-associated molecule) and c-Jun are involved in both axon regeneration and cell death suggesting that these two processes are linked. Surprisingly, Purkinje cells lose their capacity to regenerate their axon (even in the absence of myelin) during development before losing their capacity to react to an axotomy by cell death. These results emphasize the different reactions to axotomy between neuron types and underline that in Purkinje cells, the two cell decisions (axon regeneration and cell death) are differently regulated and therefore not part of the same signaling pathway.
Collapse
Affiliation(s)
- I Dusart
- UMR-7102, Université Pierre et Marie Curie, 9 Quai Saint Bernard, 75005 Paris, France.
| | | | | | | | | | | | | |
Collapse
|
46
|
Gomes-Leal W, Corkill DJ, Freire MA, Picanço-Diniz CW, Perry VH. Astrocytosis, microglia activation, oligodendrocyte degeneration, and pyknosis following acute spinal cord injury. Exp Neurol 2004; 190:456-67. [PMID: 15530884 DOI: 10.1016/j.expneurol.2004.06.028] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Revised: 05/17/2004] [Accepted: 06/13/2004] [Indexed: 11/26/2022]
Abstract
Glial activation and degeneration are important outcomes in the pathophysiology of acute brain and spinal cord injury (SCI). Our main goal was to investigate the pattern of glial activation and degeneration during secondary degeneration in both gray matter (GM) and white matter (WM) following SCI. Adult rats were deeply anesthetized and injected with 20 nmol of N-methyl-D-aspartate (NMDA) into the ventral horn of rat spinal cord (SC) on T7. Animals were perfused after survival times of 1, 3, and 7 days. Ten-micrometer sections were submitted to immunocytochemistry for activated macrophages/microglia, astrocytes, oligodendrocytes, and myelin. Astrocyte activation was more intense in the vacuolated white matter than in gray matter and was first noticed in this former region. Microglial activation was more intense in the gray matter and was clear by 24 h following NMDA injection. Both astrocytosis and microglial activation were more intense in the later survival times. Conspicuous WM vacuolation was present mainly at the 3-day survival time and decreased by 7 days after the primary damage. Quantitative analysis revealed an increase in the number of pyknotic bodies mainly at the 7-day survival time in both ventral and lateral white matter. These pyknotic bodies were frequently found inside white matter vacuoles like for degenerating oligodendrocytes. These results suggest a differential pattern of astrocytosis and microglia activation for white and gray matter following SCI. This phenomenon can be related to the different pathological outcomes for this two SC regions following acute injury.
Collapse
Affiliation(s)
- W Gomes-Leal
- Laboratory of Functional Neuroanatomy, Department of Morphology, Federal University of Pará, Brazil.
| | | | | | | | | |
Collapse
|
47
|
Camand E, Morel MP, Faissner A, Sotelo C, Dusart I. Long-term changes in the molecular composition of the glial scar and progressive increase of serotoninergic fibre sprouting after hemisection of the mouse spinal cord. Eur J Neurosci 2004; 20:1161-76. [PMID: 15341588 DOI: 10.1111/j.1460-9568.2004.03558.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The scarring process occurring after adult central nervous system injury and the subsequent increase in the expression of certain extracellular matrix molecules are known to contribute to the failure of axon regeneration. This study provides an immunohistochemical analysis of temporal changes (8 days to 1 year) in the cellular and molecular response of the Swiss mouse spinal cord to a dorsal hemisection and its correlation with the axonal growth properties of a descending pathway, the serotoninergic axons. In this lesion model, no cavity forms at the centre of the lesion. Instead, a dense fibronectin-positive tissue matrix occupies the centre of the lesion, surrounded by a glial scar mainly constituted by reactive astrocytes. NG2 proteoglycan and tenascin-C, potential axon growth inhibitors, are constantly associated with the central region. In the glial scar, tenascin-C is never observed and the expression of chondroitin sulphate proteoglycans (revealed with CS-56 and anti-NG2 antibodies) highly increases in the week following injury to progressively return to their control level. In parallel, there is an increasing expression of the polysialilated neural cell adhesion molecule by reactive astrocytes. These molecular changes are correlated with a sprouting process of serotoninergic axons in the glial scar, except in a small area in contact with the central region. All these observations suggest that while a part of the glial scar progressively becomes permissive to axon regeneration after mouse spinal cord injury, the border of the glial scar, in contact with the fibronectin-positive tissue matrix, is the real barrier to prevent axon regeneration.
Collapse
Affiliation(s)
- Emeline Camand
- CNRS UMR-7102 NPA, Université Paris 6, Case 12 Bat B 6étage, 9 quai Saint-Bernard, 75005, France
| | | | | | | | | |
Collapse
|
48
|
Profyris C, Cheema SS, Zang D, Azari MF, Boyle K, Petratos S. Degenerative and regenerative mechanisms governing spinal cord injury. Neurobiol Dis 2004; 15:415-36. [PMID: 15056450 DOI: 10.1016/j.nbd.2003.11.015] [Citation(s) in RCA: 338] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Revised: 11/03/2003] [Accepted: 11/14/2003] [Indexed: 12/17/2022] Open
Abstract
Spinal cord injury (SCI) is a major cause of disability, and at present, there is no universally accepted treatment. The functional decline following SCI is contributed to both direct mechanical injury and secondary pathophysiological mechanisms that are induced by the initial trauma. These mechanisms initially involve widespread haemorrhage at the site of injury and necrosis of central nervous system (CNS) cellular components. At later stages of injury, the cord is observed to display reactive gliosis. The actions of astrocytes as well as numerous other cells in this response create an environment that is highly nonpermissive to axonal regrowth. Also manifesting important effects is the immune system. The early recruitment of neutrophils and at later stages, macrophages to the site of insult cause exacerbation of injury. However, at more chronic stages, macrophages and recruited T helper cells may potentially be helpful by providing trophic support for neuronal and non-neuronal components of the injured CNS. Within this sea of injurious mechanisms, the oligodendrocytes appear to be highly vulnerable. At chronic stages of SCI, a large number of oligodendrocytes undergo apoptosis at sites that are distant to the vicinity of primary injury. This leads to denudement of axons and deterioration of their conductive abilities, which adds significantly to functional decline. By indulging into the molecular mechanisms that cause oligodendrocyte apoptosis and identifying potential targets for therapeutic intervention, the prevention of this apoptotic wave will be of tremendous value to individuals living with SCI.
Collapse
Affiliation(s)
- Christos Profyris
- Motor Neuron Disease and Paralysis Laboratory, Neural Injury and Repair Group, The Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria 3010, Australia
| | | | | | | | | | | |
Collapse
|
49
|
Stirling DP, Khodarahmi K, Liu J, McPhail LT, McBride CB, Steeves JD, Ramer MS, Tetzlaff W. Minocycline treatment reduces delayed oligodendrocyte death, attenuates axonal dieback, and improves functional outcome after spinal cord injury. J Neurosci 2004; 24:2182-90. [PMID: 14999069 PMCID: PMC6730425 DOI: 10.1523/jneurosci.5275-03.2004] [Citation(s) in RCA: 397] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Minocycline has been demonstrated to be neuroprotective after spinal cord injury (SCI). However, the cellular consequences of minocycline treatment on the secondary injury response are poorly understood. We examined the ability of minocycline to reduce oligodendrocyte apoptosis, microglial/macrophage activation, corticospinal tract (CST) dieback, and lesion size and to improve functional outcome after SCI. Adult rats were subjected to a C7-C8 dorsal column transection, and the presence of apoptotic oligodendrocytes was assessed within the ascending sensory tract (AST) and descending CST in segments (3-7 mm) both proximal and distal to the injury site. Surprisingly, the numbers of dying oligodendrocytes in the proximal and distal segments were comparable, suggesting more than the lack of axon-cell body contiguity played a role in their demise. Minocycline or vehicle control was injected into the intraperitoneal cavity 30 min and 8 hr after SCI and thereafter twice daily for 2 d. We report a reduction of apoptotic oligodendrocytes and microglia within both proximal and distal segments of the AST after minocycline treatment, using immunostaining for active caspase-3 and Hoechst 33258 staining in combination with cell-specific markers. Activated microglial/macrophage density was reduced remote to the lesion as well as at the lesion site. Both CST dieback and lesion size were diminished after minocycline treatment. Footprint analysis revealed improved functional outcome after minocycline treatment. Thus, minocycline ameliorates multiple secondary events after SCI, rendering this clinically used drug an attractive candidate for SCI treatment trials.
Collapse
Affiliation(s)
- David P Stirling
- International Collaboration On Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Whetstone WD, Hsu JYC, Eisenberg M, Werb Z, Noble-Haeusslein LJ. Blood-spinal cord barrier after spinal cord injury: relation to revascularization and wound healing. J Neurosci Res 2003; 74:227-39. [PMID: 14515352 PMCID: PMC2837839 DOI: 10.1002/jnr.10759] [Citation(s) in RCA: 203] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Spinal cord injury produces prominent disruption of the blood-spinal cord barrier. We have defined the blood-spinal cord barrier breakdown to the protein luciferase (61 kDa) in the acutely injured murine spinal cord and during revascularization. We show that newly formed and regenerating blood vessels that have abnormal permeability exhibit differential expression of the glucose-1 transporter (Glut-1), and that its expression is dependent on astrocytes. There was overt extravasation of luciferase within the first hour after injury, a period that coincided with marked tissue disruption within the epicenter of the lesion. Although there was a significant reduction in the number of blood vessels relative to controls by 24 hr after injury, abnormal barrier permeability remained significantly elevated. A second peak of abnormal barrier permeability at 3-7 days postinjury coincided with prominent revascularization of the epicenter. The barrier to luciferase was restored by 21 days postinjury and vascularity was similar to that of controls. During wound-healing process, the cord was reorganized into distinct domains. Between 14 and 21 days postinjury, each domain consisted primarily of nonneuronal cells, including macrophages. Astrocytes were limited characteristically to the perimeter of each domain. Only blood vessels affiliated closely with astrocytes in the perimeter expressed Glut-1, whereas blood vessels within each domain of the repairing cord did not express it. Together, these data demonstrate that both injured and regenerating vessels exhibit abnormal permeability and suggest that Glut-1 expression during revascularization is dependent on the presence of astrocytes.
Collapse
Affiliation(s)
- William D. Whetstone
- Division of Emergency Medicine, Department of Medicine, University of California, San Francisco
| | - Jung-Yu C. Hsu
- Department of Neurological Surgery, University of California, San Francisco
| | - Manuel Eisenberg
- Department of Neurological Surgery, University of California, San Francisco
| | - Zena Werb
- Department of Anatomy, University of California, San Francisco
| | - Linda J. Noble-Haeusslein
- Department of Neurological Surgery, University of California, San Francisco
- Correspondence to: Linda Noble, 521 Room C224, Parnassus Avenue, University of California, San Francisco, CA 94143-0520.
| |
Collapse
|