1
|
Satkunendrarajah K, Karadimas SK, Fehlings MG. Spinal cord injury and degenerative cervical myelopathy. Handb Clin Neurol 2022; 189:241-257. [PMID: 36031307 DOI: 10.1016/b978-0-323-91532-8.00006-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Spinal cord injury (SCI) often results in impaired respiratory function. Paresis or paralysis of inspiratory and expiratory muscles can lead to respiratory dysfunction depending on the level and severity of the injury, which can affect the management and care of SCI patients. Respiratory dysfunction after SCI is more severe in high cervical injuries, with vital capacity (VC) being an essential indicator of overall respiratory health. Respiratory complications include hypoventilation, a reduction in surfactant production, mucus plugging, atelectasis, and pneumonia. Respiratory management includes mechanical ventilation and tracheostomy in high cervical SCI, while noninvasive ventilation is more common in patients with lower cervical and thoracic injuries. Mechanical ventilation can negatively impact the function of the diaphragm and weaning should start as soon as possible. Patients can sometimes be weaned from mechanical ventilation with assistance of electrical stimulation of the phrenic nerve or the diaphragm. Respiratory muscle training regimens may also improve patients' inspiratory function following SCI. Despite the critical advances in preventing, diagnosing, and treating respiratory complications, they continue to significantly affect persons living with SCI. Additional studies of interventions to reduce respiratory complications are likely to further decrease the morbidity and mortality associated with these injuries.
Collapse
Affiliation(s)
- Kajana Satkunendrarajah
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; Department of Neuroscience, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Spyridon K Karadimas
- Division of Neurosurgery and Spine Program, Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Michael G Fehlings
- Division of Neurosurgery and Spine Program, Department of Surgery, University of Toronto, Toronto, ON, Canada; Division of Genetics and Development, Krembil Brain Institute, University Health Network, Toronto, ON, Canada.
| |
Collapse
|
2
|
Laliberte AM, Karadimas SK, Vidal PM, Satkunendrarajah K, Fehlings MG. Mir21 modulates inflammation and sensorimotor deficits in cervical myelopathy: data from humans and animal models. Brain Commun 2021; 3:fcaa234. [PMID: 33604572 PMCID: PMC7878254 DOI: 10.1093/braincomms/fcaa234] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 11/24/2020] [Accepted: 11/27/2020] [Indexed: 12/12/2022] Open
Abstract
Degenerative cervical myelopathy is a common condition resulting from chronic compression of the spinal cord by degenerating structures of the spine. Degenerative cervical myelopathy present a wide range of outcomes, and the biological factors underlying this variability are poorly understood. Previous studies have found elevated MIR21-5p in the sub-acute and chronic neuroinflammatory environment after spinal cord injury. As chronic spinal cord neuroinflammation is a major feature of degenerative cervical myelopathy, we hypothesized that MIR21-5p may be particularly relevant to disease pathobiology, and could serve as a potential biomarker. A prospective cohort study of 69 human degenerative cervical myelopathy patients (36 male:33 female) between the ages of 30 and 78 years was performed to identify the relationship between MIR21-5p expression, symptom severity and treatment outcomes. Results from this study identified a positive correlation between elevated plasma MIR21-5p expression, initial symptom severity and poor treatment outcomes. Subsequent validation of these relationships using a mouse model of degenerative cervical myelopathy identified a similar elevation of MIR21-5p expression at 6 and 12 weeks after onset, corresponding to moderate to severe neurological deficits. To further determine how MIR21-5p affects cervical myelopathy pathobiology, this mouse model was applied to a Mir21 knockout mouse line. Deletion of the Mir21 gene preserved locomotor function on rotarod and forced swim tests, but also resulted in increased nociception based on tail flick, Von Frey filament and electrophysiological testing. Critically, Mir21 knockout mice also had reduced spinal cord inflammation, demonstrated by the reduction of Iba1+ microglia by ∼50% relative to wild-type controls. In vitro experiments using primary microglial cultures confirmed that MIR21-5p expression was greatly increased after exposure to lipopolysaccharide (pro-inflammatory), Il4 (anti-inflammatory) and hypoxia. Mir21 knockout did not appear to alter the ability of microglia to respond to these stimuli, as expression of key pro- and anti-inflammatory response genes was not significantly altered. However, target prediction algorithms identified the IL6/STAT3 pathway as a potential downstream target of MIR21-5p, and subsequent in vitro testing found that expression of components of the IL6 receptor complex, Il6ra and Il6st, were significantly higher in Mir21 knockout microglia. In aggregate, these data show that Mir21 plays a role in the progression of motor deficits and neuroinflammatory modulation in degenerative cervical myelopathy. Given this role in neuroinflammation, and its association with poor patient outcomes, MIR21-5p represents a potential therapeutic target and a new marker for prognostication.
Collapse
Affiliation(s)
- Alex M Laliberte
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON M5T2S8, Canada
| | - Spyridon K Karadimas
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON M5T2S8, Canada
| | - Pia M Vidal
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON M5T2S8, Canada
| | - Kajana Satkunendrarajah
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON M5T2S8, Canada
| | - Michael G Fehlings
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON M5T2S8, Canada
| |
Collapse
|
3
|
Tetreault LA, Zhu MP, Wilson JR, Karadimas SK, Fehlings MG. The Impact of Riluzole on Neurobehavioral Outcomes in Preclinical Models of Traumatic and Nontraumatic Spinal Cord Injury: Results From a Systematic Review of the Literature. Global Spine J 2020; 10:216-229. [PMID: 32206521 PMCID: PMC7076594 DOI: 10.1177/2192568219835516] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
STUDY DESIGN Systematic review. OBJECTIVE To evaluate the impact of riluzole on neurobehavioral outcomes in preclinical models of nontraumatic and traumatic spinal cord injury (SCI). METHODS An extensive search of the literature was conducted in Medline, EMBASE, and Medline in Process. Studies were included if they evaluated the impact of riluzole on neurobehavioral outcomes in preclinical models of nontraumatic and traumatic SCI. Extensive data were extracted from relevant studies, including sample characteristics, injury model, outcomes assessed, timing of evaluation, and main results. The SYRCLE checklist was used to assess various sources of bias. RESULTS The search yielded a total of 3180 unique citations. A total of 16 studies were deemed relevant and were summarized in this review. Sample sizes ranged from 14 to 90, and injury models included traumatic SCI (n = 9), degenerative cervical myelopathy (n = 2), and spinal cord-ischemia (n = 5). The most commonly assessed outcome measures were BBB (Basso, Beattie, Besnahan) locomotor score and von Frey filament testing. In general, rats treated with riluzole exhibited significantly higher BBB locomotor scores than controls. Furthermore, riluzole significantly increased withdrawal thresholds to innocuous stimuli and tail flick latency following application of radiant heat stimuli. Finally, rats treated with riluzole achieved superior results on many components of gait assessment. CONCLUSION In preclinical models of traumatic and nontraumatic SCI, riluzole significantly improves locomotor scores, gait function, and neuropathic pain. This review provides the background information necessary to interpret the results of clinical trials on the impact of riluzole in traumatic and nontraumatic SCI.
Collapse
Affiliation(s)
- Lindsay A. Tetreault
- Toronto Western Hospital, Toronto, Ontario, Canada,University of Toronto, Toronto, Ontario, Canada,University College Cork, Cork, Ireland
| | - Mary P. Zhu
- University of Toronto, Toronto, Ontario, Canada,St Michael’s Hospital, Toronto, Ontario, Canada
| | - Jefferson R. Wilson
- University of Toronto, Toronto, Ontario, Canada,St Michael’s Hospital, Toronto, Ontario, Canada
| | - Spyridon K. Karadimas
- Toronto Western Hospital, Toronto, Ontario, Canada,University of Toronto, Toronto, Ontario, Canada
| | - Michael G. Fehlings
- Toronto Western Hospital, Toronto, Ontario, Canada,University of Toronto, Toronto, Ontario, Canada,Michael G. Fehlings, Division of Neurosurgery, Toronto Western Hospital, University of Toronto, 399 Bathurst Street, Toronto, Ontario M5T2S8, Canada.
| |
Collapse
|
4
|
Karadimas SK, Satkunendrarajah K, Laliberte AM, Ringuette D, Weisspapir I, Li L, Gosgnach S, Fehlings MG. Sensory cortical control of movement. Nat Neurosci 2019; 23:75-84. [DOI: 10.1038/s41593-019-0536-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 10/08/2019] [Indexed: 01/07/2023]
|
5
|
Satkunendrarajah K, Karadimas SK, Laliberte AM, Montandon G, Fehlings MG. Cervical excitatory neurons sustain breathing after spinal cord injury. Nature 2018; 562:419-422. [DOI: 10.1038/s41586-018-0595-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/14/2018] [Indexed: 11/09/2022]
|
6
|
Fehlings MG, Karadimas SK, Kopjar B, Arnold PM. 359 Combinatorial Surgical and Neuroprotective Therapy for Cervical Spondylotic Myelopathy Results in Improved Neurological Function. Neurosurgery 2017. [DOI: 10.1093/neuros/nyx417.359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
7
|
Vidal PM, Karadimas SK, Ulndreaj A, Laliberte AM, Tetreault L, Forner S, Wang J, Foltz WD, Fehlings MG. Delayed decompression exacerbates ischemia-reperfusion injury in cervical compressive myelopathy. JCI Insight 2017; 2:92512. [PMID: 28570271 DOI: 10.1172/jci.insight.92512] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 04/27/2017] [Indexed: 01/21/2023] Open
Abstract
Degenerative cervical myelopathy (DCM) is the most common progressive nontraumatic spinal cord injury. The most common recommended treatment is surgical decompression, although the optimal timing of intervention is an area of ongoing debate. The primary objective of this study was to assess whether a delay in decompression could influence the extent of ischemia-reperfusion injury and alter the trajectory of outcome in DCM. Using a DCM mouse model, we show that decompression acutely led to a 1.5- to 2-fold increase in levels of inflammatory cytokines within the spinal cord. Delayed decompression was associated with exacerbated reperfusion injury, astrogliosis, and poorer neurological recovery. Additionally, delayed decompression was associated with prolonged elevation of inflammatory cytokines and an exacerbated peripheral monocytic inflammatory response (P < 0.01 and 0.001). In contrast, early decompression led to resolution of reperfusion-mediated inflammation, neurological improvement, and reduced hyperalgesia. Similar findings were observed in subjects from the CSM AOSpine North America and International studies, where delayed decompressive surgery resulted in poorer neurological improvement compared with patients with an earlier intervention. Our data demonstrate that delayed surgical decompression for DCM exacerbates reperfusion injury and is associated with ongoing enhanced levels of cytokine expression, microglia activation, and astrogliosis, and paralleled with poorer neurological recovery.
Collapse
Affiliation(s)
- Pia M Vidal
- Division of Genetics & Development, Toronto Western Research Institute and Spine Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada
| | - Spyridon K Karadimas
- Division of Genetics & Development, Toronto Western Research Institute and Spine Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Antigona Ulndreaj
- Division of Genetics & Development, Toronto Western Research Institute and Spine Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Alex M Laliberte
- Division of Genetics & Development, Toronto Western Research Institute and Spine Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science
| | - Lindsay Tetreault
- Department of Surgery, Division of Neurosurgery and Spine Program, University of Toronto, Toronto, Ontario, Canada
| | - Stefania Forner
- Department of Pharmacology, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Jian Wang
- Division of Genetics & Development, Toronto Western Research Institute and Spine Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada
| | - Warren D Foltz
- Spatio-Temporal Targeting and Amplification of Radiation Responses (STTARR) Innovation Centre, Department of Radiation Oncology, University Health Network, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Division of Genetics & Development, Toronto Western Research Institute and Spine Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada.,Department of Surgery, Division of Neurosurgery and Spine Program, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
8
|
Karadimas SK, Laliberte AM, Tetreault L, Chung YS, Arnold P, Foltz WD, Fehlings MG. Riluzole blocks perioperative ischemia-reperfusion injury and enhances postdecompression outcomes in cervical spondylotic myelopathy. Sci Transl Med 2016; 7:316ra194. [PMID: 26631633 DOI: 10.1126/scitranslmed.aac6524] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although surgical decompression is considered the gold standard treatment for cervical spondylotic myelopathy (CSM), a proportion of cases show postoperative decline or continue to exhibit substantial neurological dysfunction. To investigate this further, we first examined data from the prospective multicenter AOSpine North America CSM study, finding that 9.3% of patients exhibited postoperative functional decline (ΔmJOA, ≤-1) and that 44% of patients were left with substantial neurological impairment 6 months postoperatively. Notably, 4% of patients experienced perioperative neurological complications within 20 days after surgery in otherwise uneventful surgeries. To shed light on the mechanisms underlying this phenomenon and to test a combination therapeutic strategy for CSM, we performed surgical decompression in a rat model of CSM, randomizing some animals to also receive the U.S. Food and Drug Administration-approved drug riluzole. Spinal cord blood flow measurements increased after decompression surgery in rats. CSM rats showed a transient postoperative neurological decline akin to that seen in some CSM patients, suggesting that ischemia-reperfusion injury may occur after decompression surgery. Riluzole treatment attenuated oxidative DNA damage in the spinal cord and postoperative decline after decompression surgery. Mechanistic in vitro studies also demonstrated that riluzole preserved mitochondrial function and reduced oxidative damage in neurons. Rats receiving combined decompression surgery and riluzole treatment displayed long-term improvements in forelimb function associated with preservation of cervical motor neurons and corticospinal tracts compared to rats treated with decompression surgery alone.
Collapse
Affiliation(s)
- Spyridon K Karadimas
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Division of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario M5T 2S8, Canada
| | - Alex M Laliberte
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Division of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario M5T 2S8, Canada
| | - Lindsay Tetreault
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Division of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario M5T 2S8, Canada
| | - Young Sun Chung
- Division of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario M5T 2S8, Canada
| | - Paul Arnold
- Department of Neurosurgery, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Warren D Foltz
- Spatio-Temporal Targeting and Amplification of Radiation Response (STTARR) Innovation Centre, Department of Radiation Oncology, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Michael G Fehlings
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Division of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario M5T 2S8, Canada. Department of Surgery, Division of Neurosurgery and Spinal Program, University of Toronto, Toronto, Ontario M5T 2S8, Canada.
| |
Collapse
|
9
|
Karadimas SK, Satkunendrarajah K, Fehlings MG. 179 Chemogenetic Stimulation of the Lumbar Locomotor Network Enhances Motor Function Following Experimental Cervical Spinal Cord Injury. Neurosurgery 2016. [DOI: 10.1227/01.neu.0000489748.74661.5c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
10
|
Satkunendrarajah K, Nassiri F, Karadimas SK, Lip A, Yao G, Fehlings MG. Riluzole promotes motor and respiratory recovery associated with enhanced neuronal survival and function following high cervical spinal hemisection. Exp Neurol 2015; 276:59-71. [PMID: 26394202 DOI: 10.1016/j.expneurol.2015.09.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 08/03/2015] [Accepted: 09/19/2015] [Indexed: 10/23/2022]
Abstract
Cervical spinal cord injury (SCI) can result in devastating functional deficits that involve the respiratory and hand function. The mammalian spinal cord has limited ability to regenerate and restore meaningful functional recovery following SCI. Riluzole, 2-amino-6-trifluoromethoxybenzothiazole, an anti-glutamatergic drug has been shown to reduce excitotoxicity and confer neuroprotection at the site of injury following experimental SCI. Based on promising preclinical studies, riluzole is currently under Phase III clinical trial for the treatment of SCI (ClinicalTrials.gov: NCT01597518). Riluzole's anti-glutamatergic role has the potential to regulate neuronal function and provide neuroprotection and influence glutamatergic connections distal to the initial injury leading to enhanced functional recovery following SCI. In order to investigate this novel role of riluzole we used a high cervical hemisection model of SCI, which interrupts all descending input to motoneurons innervating the ipsilateral forelimb and diaphragm muscles. Following C2 spinal cord hemisection, animals were placed into one of two groups: one group received riluzole (8 mg/kg) 1 h after injury and every 12 h thereafter for 7 days at 6 mg/kg, while the second group of injured rats received vehicle solution for the same duration of time. A third group of sham injured rats underwent a C2 laminectomy without hemisection and served as uninjured control rats. Interestingly, this study reports a significant loss of motoneurons within the cervical spinal cord caudal to C2 hemisection injury. Disruption of descending input led to a decrease in glutamatergic synapses and motoneurons caudal to the injury while riluzole treatment significantly limited this decline. Functionally, Hoffmann reflex recordings revealed an increase in the excitability of the remaining ipsilateral cervical motoneurons and significant improvements in skilled and unskilled forelimb function and respiratory motor function in the riluzole-treated animals. In conclusion, using a C2 hemisection injury model, this study provides novel evidence of motoneuron loss caudal to the injury and supports riluzole's capacity to promote neuronal preservation and function of neural network caudal to the SCI resulting in early and sustained functional improvements.
Collapse
Affiliation(s)
- K Satkunendrarajah
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada
| | - F Nassiri
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada
| | - S K Karadimas
- Department of Surgery, University of Toronto, Ontario, Canada
| | - A Lip
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada
| | - G Yao
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada
| | - M G Fehlings
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Center, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Ontario, Canada.
| |
Collapse
|
11
|
Forgione N, Karadimas SK, Foltz WD, Satkunendrarajah K, Lip A, Fehlings MG. Bilateral contusion-compression model of incomplete traumatic cervical spinal cord injury. J Neurotrauma 2014; 31:1776-88. [PMID: 24949719 DOI: 10.1089/neu.2014.3388] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Despite the increasing incidence and prevalence of cervical spinal cord injury (cSCI), we lack clinically relevant animal models that can be used to study the pathomechanisms of this injury and test new therapies. Here, we characterize a moderate cervical contusion-compression model in rats that is similar to incomplete traumatic cSCI in humans. We characterized the effects of 18-g clip-compression injury at cervical level C6 over an 8-week recovery period. Using Luxol fast blue/hematoxylin-eosin staining in combination with quantitative stereology, we determined that 18-g injury results in loss of gray matter (GM), white matter (WM), as well as in cavity formation. Magnetization transfer and T2-weighted magnetic resonance imaging were used to analyze lesion dynamics in vivo. This analysis demonstrated that both techniques are able to differentiate between the injury epicenter, subpial rim, and WM distal to the injury. Neurobehavioral assessment of locomotor function using Basso, Beattie, and Bresnahan (BBB) scoring and CatWalk revealed limited recovery from clip-compression injury at C6. Testing of forelimb function using grip strength demonstrated significant forelimb dysfunction, similar to the loss of upper-limb motor function observed in human cSCI. Sensory-evoked potentials recorded from the forelimb and Hoffman reflex recorded from the hindlimb confirmed the fore- and hindlimb deficits observed in our neurobehavioral analysis. Here, we have characterized a clip-compression model of incomplete cSCI that closely models this condition in humans. This work directly addresses the current lack of clinically relevant models of cSCI and will thus contribute to improved success in the translation of putative therapies into the clinic.
Collapse
Affiliation(s)
- Nicole Forgione
- 1 Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Center, University Health Network , Toronto, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
12
|
Figley SA, Liu Y, Karadimas SK, Satkunendrarajah K, Fettes P, Spratt SK, Lee G, Ando D, Surosky R, Giedlin M, Fehlings MG. Delayed administration of a bio-engineered zinc-finger VEGF-A gene therapy is neuroprotective and attenuates allodynia following traumatic spinal cord injury. PLoS One 2014; 9:e96137. [PMID: 24846143 PMCID: PMC4028194 DOI: 10.1371/journal.pone.0096137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 04/03/2014] [Indexed: 02/01/2023] Open
Abstract
Following spinal cord injury (SCI) there are drastic changes that occur in the spinal microvasculature, including ischemia, hemorrhage, endothelial cell death and blood-spinal cord barrier disruption. Vascular endothelial growth factor-A (VEGF-A) is a pleiotropic factor recognized for its pro-angiogenic properties; however, VEGF has recently been shown to provide neuroprotection. We hypothesized that delivery of AdV-ZFP-VEGF--an adenovirally delivered bio-engineered zinc-finger transcription factor that promotes endogenous VEGF-A expression--would result in angiogenesis, neuroprotection and functional recovery following SCI. This novel VEGF gene therapy induces the endogenous production of multiple VEGF-A isoforms; a critical factor for proper vascular development and repair. Briefly, female Wistar rats--under cyclosporin immunosuppression--received a 35 g clip-compression injury and were administered AdV-ZFP-VEGF or AdV-eGFP at 24 hours post-SCI. qRT-PCR and Western Blot analysis of VEGF-A mRNA and protein, showed significant increases in VEGF-A expression in AdV-ZFP-VEGF treated animals (p<0.001 and p<0.05, respectively). Analysis of NF200, TUNEL, and RECA-1 indicated that AdV-ZFP-VEGF increased axonal preservation (p<0.05), reduced cell death (p<0.01), and increased blood vessels (p<0.01), respectively. Moreover, AdV-ZFP-VEGF resulted in a 10% increase in blood vessel proliferation (p<0.001). Catwalk™ analysis showed AdV-ZFP-VEGF treatment dramatically improves hindlimb weight support (p<0.05) and increases hindlimb swing speed (p<0.02) when compared to control animals. Finally, AdV-ZFP-VEGF administration provided a significant reduction in allodynia (p<0.01). Overall, the results of this study indicate that AdV-ZFP-VEGF administration can be delivered in a clinically relevant time-window following SCI (24 hours) and provide significant molecular and functional benefits.
Collapse
Affiliation(s)
- Sarah A Figley
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Yang Liu
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada
| | - Spyridon K Karadimas
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Kajana Satkunendrarajah
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada
| | - Peter Fettes
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada
| | - S Kaye Spratt
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Gary Lee
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Dale Ando
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Richard Surosky
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Martin Giedlin
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
13
|
Karadimas SK, Gatzounis G, Fehlings MG. Pathobiology of cervical spondylotic myelopathy. Eur Spine J 2014; 24 Suppl 2:132-8. [DOI: 10.1007/s00586-014-3264-4] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/20/2014] [Accepted: 02/20/2014] [Indexed: 11/25/2022]
|
14
|
Iwasaki M, Wilcox JT, Nishimura Y, Zweckberger K, Suzuki H, Wang J, Liu Y, Karadimas SK, Fehlings MG. Synergistic effects of self-assembling peptide and neural stem/progenitor cells to promote tissue repair and forelimb functional recovery in cervical spinal cord injury. Biomaterials 2014; 35:2617-29. [DOI: 10.1016/j.biomaterials.2013.12.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 12/11/2013] [Indexed: 01/13/2023]
|
15
|
Moon ES, Karadimas SK, Yu WR, Austin JW, Fehlings MG. Riluzole attenuates neuropathic pain and enhances functional recovery in a rodent model of cervical spondylotic myelopathy. Neurobiol Dis 2014; 62:394-406. [DOI: 10.1016/j.nbd.2013.10.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 10/04/2013] [Accepted: 10/22/2013] [Indexed: 12/15/2022] Open
|
16
|
Karadimas SK, Moon ES, Yu WR, Satkunendrarajah K, Kallitsis JK, Gatzounis G, Fehlings MG. A novel experimental model of cervical spondylotic myelopathy (CSM) to facilitate translational research. Neurobiol Dis 2013; 54:43-58. [PMID: 23466695 DOI: 10.1016/j.nbd.2013.02.013] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 02/01/2013] [Accepted: 02/19/2013] [Indexed: 12/15/2022] Open
Abstract
Cervical spondylotic myelopathy (CSM) is the most common form of spinal cord impairment in adults. However critical gaps in our knowledge of the pathobiology of this disease have limited therapeutic advances. To facilitate progress in the field of regenerative medicine for CSM, we have developed a unique, clinically relevant model of CSM in rats. To model CSM, a piece of synthetic aromatic polyether, to promote local calcification, was implanted microsurgically under the C6 lamina in rats. We included a sham group in which the material was removed 30s after the implantation. MRI confirmed postero-anterior cervical spinal cord compression at the C6 level. Rats modeling CSM demonstrated insidious development of a broad-based, ataxic, spastic gait, forelimb weakness and sensory changes. No neurological deficits were noted in the sham group during the course of the study. Spasticity of the lower extremities was confirmed by a significantly greater H/M ratio in CSM rats in H reflex recordings compared to sham. Rats in the compression group experienced significant gray and white matter loss, astrogliosis, anterior horn cell loss and degeneration of the corticospinal tract. Moreover, chronic progressive posterior compression of the cervical spinal cord resulted in compromise of the spinal cord microvasculature, blood-spinal cord barrier disruption, inflammation and activation of apoptotic signaling pathways in neurons and oligodendrocytes. Finally, CSM rats were successfully subjected to decompressive surgery as confirmed by MRI. In summary, this novel rat CSM model reproduces the chronic and progressive nature of human CSM, produces neurological deficits and neuropathological features accurately mimicking the human condition, is MRI compatible and importantly, allows for surgical decompression.
Collapse
Affiliation(s)
- Spyridon K Karadimas
- Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
17
|
Kalsi-Ryan S, Karadimas SK, Fehlings MG. Cervical spondylotic myelopathy: the clinical phenomenon and the current pathobiology of an increasingly prevalent and devastating disorder. Neuroscientist 2012. [PMID: 23204243 DOI: 10.1177/1073858412467377] [Citation(s) in RCA: 259] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cervical spondylotic myelopathy (CSM) is a common disorder involving chronic progressive compression of the cervical spinal cord due to degenerative disc disease, spondylosis, or other degenerative pathology. CSM is the most common form of spinal cord impairment and causes functional decline leading to reduced independence and quality of life. Despite a sound understanding of the disease process, clinical presentation and management, a universal definition of CSM and a standardized index of severity are not currently used universally. Work is required to develop a definition and establish clinical predictors of progression to improve management of CSM. Despite advances in decompressive and reconstructive surgery, patients are often left with residual disability. Gaps in knowledge of the pathobiology of CSM have limited therapeutic advances to complement surgery. Although the histopathologic and pathophysiologic similarities between CSM and traumatic spinal cord injury have long been acknowledged, the unique pathomechanisms of CSM remain unexplored. Increased efforts to elucidate CSM pathobiology could lead to the discovery of novel therapeutic targets for human CSM and other spinal cord diseases. Here, the natural history of CSM, epidemiology, clinical presentation, and current methods of clinical management are reported, along with the current state of basic scientific research in the field.
Collapse
|