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Thomas SJ, Ghosh B, Wang Z, Yang M, Nong J, Severa J, Wright MC, Zhong Y, Lepore AC. Hepatocyte Growth Factor Delivery to Injured Cervical Spinal Cord Using an Engineered Biomaterial Protects Respiratory Neural Circuitry and Preserves Functional Diaphragm Innervation. J Neurotrauma 2024. [PMID: 39078323 DOI: 10.1089/neu.2024.0084] [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: 07/31/2024] Open
Abstract
A major portion of spinal cord injury (SCI) cases occur in the cervical region, where essential components of the respiratory neural circuitry are located. Phrenic motor neurons (PhMNs) housed at cervical spinal cord level C3-C5 directly innervate the diaphragm, and SCI-induced damage to these cells severely impairs respiratory function. In this study, we tested a biomaterial-based approach aimed at preserving this critical phrenic motor circuitry after cervical SCI by locally delivering hepatocyte growth factor (HGF). HGF is a potent mitogen that promotes survival, proliferation, migration, repair, and regeneration of a number of different cell and tissue types in response to injury. We developed a hydrogel-based HGF delivery system that can be injected into the intrathecal space for local delivery of high levels of HGF without damaging the spinal cord. Implantation of HGF hydrogel after unilateral C5 contusion-type SCI in rats preserved diaphragm function, as assessed by in vivo recordings of both compound muscle action potentials and inspiratory electromyography amplitudes. HGF hydrogel also preserved PhMN innervation of the diaphragm, as assessed by both retrograde PhMN tracing and detailed neuromuscular junction morphological analysis. Furthermore, HGF hydrogel significantly decreased lesion size and degeneration of cervical motor neuron cell bodies, as well as reduced levels surrounding the injury site of scar-associated chondroitin sulfate proteoglycan molecules that limit axon growth capacity. Our findings demonstrate that local biomaterial-based delivery of HGF hydrogel to injured cervical spinal cord is an effective strategy for preserving respiratory circuitry and diaphragm function.
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Affiliation(s)
- Samantha J Thomas
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Zhicheng Wang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Mengxi Yang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jia Nong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jenna Severa
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, Pennsylvania, USA
| | - Yinghui Zhong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Michel-Flutot P, Cheng L, Thomas SJ, Lisi B, Schwartz H, Lam S, Lyttle M, Jaffe DA, Smith G, Li S, Wright MC, Lepore AC. PTEN inhibition promotes robust growth of bulbospinal respiratory axons and partial recovery of diaphragm function in a chronic model of cervical contusion spinal cord injury. Exp Neurol 2024; 378:114816. [PMID: 38789023 PMCID: PMC11200215 DOI: 10.1016/j.expneurol.2024.114816] [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: 01/10/2024] [Revised: 03/25/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024]
Abstract
High spinal cord injury (SCI) leads to persistent and debilitating compromise in respiratory function. Cervical SCI not only causes the death of phrenic motor neurons (PhMNs) that innervate the diaphragm, but also damages descending respiratory pathways originating in the rostral ventral respiratory group (rVRG) located in the brainstem, resulting in denervation and consequent silencing of spared PhMNs located caudal to injury. It is imperative to determine whether interventions targeting rVRG axon growth and respiratory neural circuit reconnection are efficacious in chronic cervical contusion SCI, given that the vast majority of individuals are chronically-injured and most cases of SCI involve contusion-type damage to the cervical region. We therefore employed a rat model of chronic cervical hemicontusion to test therapeutic manipulations aimed at reconstructing damaged rVRG-PhMN-diaphragm circuitry to achieve recovery of respiratory function. At a chronic time point post-injury, we systemically administered: an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential; an antagonist peptide directed against receptor-type protein tyrosine phosphatase sigma (PTPσ), another important negative regulator of axon growth capacity; or a combination of these two peptides. PTEN antagonist peptide (PAP4) promoted partial recovery of diaphragm motor activity out to nine months post-injury (though this effect depended on the anesthetic regimen used during recording), while PTPσ peptide did not impact diaphragm function after cervical SCI. Furthermore, PAP4 promoted robust growth of descending bulbospinal rVRG axons caudal to the injury within the denervated portion of the PhMN pool, while PTPσ peptide did not affect rVRG axon growth at this location that is critical to control of diaphragmatic respiratory function. In conclusion, we find that, when PTEN inhibition is targeted at a chronic time point following cervical contusion, our non-invasive PAP4 strategy can successfully promote significant regrowth of damaged respiratory neural circuitry and also partial recovery of diaphragm motor function.
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Affiliation(s)
- Pauline Michel-Flutot
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Lan Cheng
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Samantha J Thomas
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Brianna Lisi
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Harrison Schwartz
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Sandy Lam
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Megan Lyttle
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - David A Jaffe
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - George Smith
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 191405104, USA
| | - Shuxin Li
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 191405104, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, PA 19038, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Rana S, Thakre PP, Fuller DD. Ampakines increase diaphragm activation following mid-cervical contusion injury in rats. Exp Neurol 2024; 376:114769. [PMID: 38582278 DOI: 10.1016/j.expneurol.2024.114769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/08/2024]
Abstract
Ampakines are positive allosteric modulators of AMPA receptors. We hypothesized that low-dose ampakine treatment increases diaphragm electromyogram (EMG) activity after mid-cervical contusion injury in rats. Adult male and female Sprague Dawley rats were implanted with in-dwelling bilateral diaphragm EMG electrodes. Rats received a 150 kDyn C4 unilateral contusion (C4Ct). At 4- and 14-days following C4Ct, rats were given an intravenous bolus of ampakine CX717 (5 mg/kg, n = 10) or vehicle (2-hydroxypropyl-beta-cyclodextrin; HPCD; n = 10). Diaphragm EMG was recorded while breathing was assessed using whole-body plethysmography. At 4-days, ampakine administration caused an immediate and sustained increase in bilateral peak inspiratory diaphragm EMG bursting and ventilation. The vehicle had no impact on EMG bursting. CX717 treated rats were able to increase EMG activity during a respiratory challenge to a greater extent vs. vehicle treated. Rats showed a considerable degree of spontaneous recovery of EMG bursting by 14 days, and the impact of CX717 delivery was blunted as compared to 4-days. Direct recordings from the phrenic nerve at 21-24 days following C4Ct confirmed that ampakines stimulated bilateral phrenic neural output in injured rats. We conclude that low-dose intravenous treatment with a low-impact ampakine can enhance diaphragm activation shortly following mid-cervical contusion injury, when deficits in diaphragm activation are prominent.
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Affiliation(s)
- Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States of America; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, United States of America; Breathing Research and Therapeutics Center, Gainesville, FL 32610, United States of America
| | - Prajwal P Thakre
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States of America; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, United States of America; Breathing Research and Therapeutics Center, Gainesville, FL 32610, United States of America
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, United States of America; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, United States of America; Breathing Research and Therapeutics Center, Gainesville, FL 32610, United States of America.
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Urban MW, Charsar BA, Heinsinger NM, Markandaiah SS, Sprimont L, Zhou W, Brown EV, Henderson NT, Thomas SJ, Ghosh B, Cain RE, Trotti D, Pasinelli P, Wright MC, Dalva MB, Lepore AC. EphrinB2 knockdown in cervical spinal cord preserves diaphragm innervation in a mutant SOD1 mouse model of ALS. eLife 2024; 12:RP89298. [PMID: 38224498 PMCID: PMC10945582 DOI: 10.7554/elife.89298] [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] [Indexed: 01/17/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by motor neuron loss. Importantly, non-neuronal cell types such as astrocytes also play significant roles in disease pathogenesis. However, mechanisms of astrocyte contribution to ALS remain incompletely understood. Astrocyte involvement suggests that transcellular signaling may play a role in disease. We examined contribution of transmembrane signaling molecule ephrinB2 to ALS pathogenesis, in particular its role in driving motor neuron damage by spinal cord astrocytes. In symptomatic SOD1G93A mice (a well-established ALS model), ephrinB2 expression was dramatically increased in ventral horn astrocytes. Reducing ephrinB2 in the cervical spinal cord ventral horn via viral-mediated shRNA delivery reduced motor neuron loss and preserved respiratory function by maintaining phrenic motor neuron innervation of diaphragm. EphrinB2 expression was also elevated in human ALS spinal cord. These findings implicate ephrinB2 upregulation as both a transcellular signaling mechanism in mutant SOD1-associated ALS and a promising therapeutic target.
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Affiliation(s)
- Mark W Urban
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Brittany A Charsar
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Nicolette M Heinsinger
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Shashirekha S Markandaiah
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Lindsay Sprimont
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Wei Zhou
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Eric V Brown
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Nathan T Henderson
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Samantha J Thomas
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Biswarup Ghosh
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Rachel E Cain
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Davide Trotti
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Piera Pasinelli
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson UniversityPhiladelphiaUnited States
| | - Megan C Wright
- Department of Biology, Arcadia UniversityGlensideUnited States
| | - Matthew B Dalva
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
- Department of Cell and Molecular Biology, Tulane Brain Institute, Tulane UniversityNew OrleansUnited States
| | - Angelo C Lepore
- Department of Neuroscience, Jefferson Synaptic Biology Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson UniversityPhiladelphiaUnited States
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5
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Michel-Flutot P, Cheng L, Thomas SJ, Lisi B, Schwartz H, Lam S, Lyttle M, Jaffe DA, Smith G, Li S, Wright MC, Lepore AC. PTEN inhibition promotes robust growth of bulbospinal respiratory axons and partial recovery of diaphragm function in a chronic model of cervical contusion spinal cord injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575021. [PMID: 38260313 PMCID: PMC10802567 DOI: 10.1101/2024.01.10.575021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
High spinal cord injury (SCI) leads to persistent and debilitating compromise in respiratory function. Cervical SCI not only causes the death of phrenic motor neurons (PhMNs) that innervate the diaphragm, but also damages descending respiratory pathways originating in the rostral ventral respiratory group (rVRG) located in the brainstem, resulting in denervation and consequent silencing of spared PhMNs located caudal to injury. It is imperative to determine whether interventions targeting rVRG axon growth and respiratory neural circuit reconnection are efficacious in chronic cervical contusion SCI, given that the vast majority of individuals are chronically-injured and most cases of SCI involve contusion-type damage to the cervical region. We therefore employed a clinically-relevant rat model of chronic cervical hemicontusion to test therapeutic manipulations aimed at reconstructing damaged rVRG-PhMN-diaphragm circuitry to achieve recovery of respiratory function. At a chronic time point post-injury, we systemically administered: an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential; an antagonist peptide directed against receptor-type protein tyrosine phosphatase sigma (PTPσ), another important negative regulator of axon growth capacity; or a combination of these two peptides. PTEN antagonist peptide (PAP4) promoted partial recovery of diaphragm motor activity out to nine months post-injury, while PTPσ peptide did not impact diaphragm function after cervical SCI. Furthermore, PAP4 promoted robust growth of descending bulbospinal rVRG axons caudal to the injury within the denervated portion of the PhMN pool, while PTPσ peptide did not affect rVRG axon growth at this location that is critical to control of diaphragmatic respiratory function. In conclusion, we find that, when PTEN inhibition is targeted at a chronic time point following cervical contusion that is most relevant to the SCI clinical population, our non-invasive PAP4 strategy can successfully promote significant regrowth of damaged respiratory neural circuitry and also partial recovery of diaphragm motor function. HIGHLIGHTS PTEN antagonist peptide promotes partial diaphragm function recovery in chronic cervical contusion SCI.PTPσ inhibitory peptide does not impact diaphragm function recovery in chronic cervical contusion SCI.PTEN antagonist peptide promotes growth of bulbospinal rVRG axons in chronic cervical contusion SCI.PTPσ peptide does not affect rVRG axon growth in chronic cervical contusion SCI.
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Sunshine MD, Bindi VE, Nguyen BL, Doerr V, Boeno FP, Chandran V, Smuder AJ, Fuller DD. Oxygen therapy attenuates neuroinflammation after spinal cord injury. J Neuroinflammation 2023; 20:303. [PMID: 38110993 PMCID: PMC10729514 DOI: 10.1186/s12974-023-02985-6] [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: 07/10/2023] [Accepted: 12/04/2023] [Indexed: 12/20/2023] Open
Abstract
Acute hyperbaric O2 (HBO) therapy after spinal cord injury (SCI) can reduce inflammation and increase neuronal survival. To our knowledge, it is unknown if these benefits of HBO require hyperbaric vs. normobaric hyperoxia. We used a C4 lateralized contusion SCI in adult male and female rats to test the hypothesis that the combination of hyperbaria and 100% O2 (i.e. HBO) more effectively mitigates spinal inflammation and neuronal loss, and enhances respiratory recovery, as compared to normobaric 100% O2. Experimental groups included spinal intact, SCI no O2 therapy, and SCI + 100% O2 delivered at normobaric pressure (1 atmosphere, ATA), or at 2- or 3 ATA. O2 treatments lasted 1-h, commenced within 2-h of SCI, and were repeated for 10 days. The spinal inflammatory response was assessed with transcriptomics (RNAseq) and immunohistochemistry. Gene co-expression network analysis showed that the strong inflammatory response to SCI was dramatically diminished by both hyper- and normobaric O2 therapy. Similarly, both HBO and normobaric O2 treatments reduced the prevalence of immunohistological markers for astrocytes (glial fibrillary acidic protein) and microglia (ionized calcium binding adaptor molecule) in the injured spinal cord. However, HBO treatment also had unique impacts not detected in the normobaric group including upregulation of an anti-inflammatory cytokine (interleukin-4) in the plasma, and larger inspiratory tidal volumes at 10-days (whole body-plethysmography measurements). We conclude that normobaric O2 treatment can reduce the spinal inflammatory response after SCI, but pressured O2 (i.e., HBO) provides further benefit.
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Affiliation(s)
- Michael D Sunshine
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Victoria E Bindi
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Branden L Nguyen
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Vivian Doerr
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Franccesco P Boeno
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | | | - Ashley J Smuder
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA.
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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7
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Urban MW, Charsar BA, Heinsinger NM, Markandaiah SS, Sprimont L, Zhou W, Brown EV, Henderson NT, Thomas SJ, Ghosh B, Cain RE, Trotti D, Pasinelli P, Wright MC, Dalva MB, Lepore AC. EphrinB2 knockdown in cervical spinal cord preserves diaphragm innervation in a mutant SOD1 mouse model of ALS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.538887. [PMID: 37215009 PMCID: PMC10197713 DOI: 10.1101/2023.05.10.538887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by motor neuron loss. Importantly, non-neuronal cell types such as astrocytes also play significant roles in disease pathogenesis. However, mechanisms of astrocyte contribution to ALS remain incompletely understood. Astrocyte involvement suggests that transcellular signaling may play a role in disease. We examined contribution of transmembrane signaling molecule ephrinB2 to ALS pathogenesis, in particular its role in driving motor neuron damage by spinal cord astrocytes. In symptomatic SOD1-G93A mice (a well-established ALS model), ephrinB2 expression was dramatically increased in ventral horn astrocytes. Reducing ephrinB2 in the cervical spinal cord ventral horn via viral-mediated shRNA delivery reduced motor neuron loss and preserved respiratory function by maintaining phrenic motor neuron innervation of diaphragm. EphrinB2 expression was also elevated in human ALS spinal cord. These findings implicate ephrinB2 upregulation as both a transcellular signaling mechanism in mutant SOD1-associated ALS and a promising therapeutic target.
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8
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Xie Y, Zhang L, Guo S, Peng R, Gong H, Yang M. Changes in respiratory structure and function after traumatic cervical spinal cord injury: observations from spinal cord and brain. Front Neurol 2023; 14:1251833. [PMID: 37869136 PMCID: PMC10587692 DOI: 10.3389/fneur.2023.1251833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023] Open
Abstract
Respiratory difficulties and mortality following severe cervical spinal cord injury (CSCI) result primarily from malfunctions of respiratory pathways and the paralyzed diaphragm. Nonetheless, individuals with CSCI can experience partial recovery of respiratory function through respiratory neuroplasticity. For decades, researchers have revealed the potential mechanism of respiratory nerve plasticity after CSCI, and have made progress in tissue healing and functional recovery. While most existing studies on respiratory plasticity after spinal cord injuries have focused on the cervical spinal cord, there is a paucity of research on respiratory-related brain structures following such injuries. Given the interconnectedness of the spinal cord and the brain, traumatic changes to the former can also impact the latter. Consequently, are there other potential therapeutic targets to consider? This review introduces the anatomy and physiology of typical respiratory centers, explores alterations in respiratory function following spinal cord injuries, and delves into the structural foundations of modified respiratory function in patients with CSCI. Additionally, we propose that magnetic resonance neuroimaging holds promise in the study of respiratory function post-CSCI. By studying respiratory plasticity in the brain and spinal cord after CSCI, we hope to guide future clinical work.
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Affiliation(s)
- Yongqi Xie
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China
| | - Liang Zhang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China
| | - Shuang Guo
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China
- Department of Rehabilitation, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Run Peng
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China
| | - Huiming Gong
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
| | - Mingliang Yang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
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Matsumoto Y, Hayashi T, Fujiwara Y, Kubota K, Masuda M, Kawano O, Maeda T. Correlation between Respiratory Dysfunction and Dysphagia in Individuals with Acute Traumatic Cervical Spinal Cord Injury. Spine Surg Relat Res 2023; 7:327-332. [PMID: 37636150 PMCID: PMC10447182 DOI: 10.22603/ssrr.2022-0180] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 01/12/2023] [Indexed: 03/14/2023] Open
Abstract
Introduction Aspiration pneumonia is one of the most frequent and fatal life-threatening complications among individuals with acute traumatic cervical spinal cord injury (CSCI). However, the mechanism of dysphagia among individuals with CSCI is not well understood. Morbidity and mortality associated with CSCI may result from the interplay between respiratory dysfunction and dysphagia. This study aimed to elucidate the effect of respiratory dysfunction on the swallowing function of individuals with acute traumatic CSCI. Methods A prospective cohort study was conducted involving 54 individuals with acute traumatic CSCI who were admitted within 2 weeks following injury. Dysphagia was evaluated using the Dysphagia Severity Scale (DSS) and the Functional Oral Intake Scale (FOIS). Respiratory function was evaluated by measuring the cough peak flow (CPF), forced expiratory volume in 1 s (FEV1.0), FEV1.0/forced vital capacity (FEV1.0%), and percent vital capacity (%VC). We recorded these parameters at weeks 2, 4, 8, and 12 following injury and analyzed pertinent changes over time and significant correlations. Results Among 54 individuals (46 men and 8 women) recruited in this study, 48 (88.9%) had restrictive ventilatory impairment and 17 (31.5%) had severe dysphagia (DSS level 1-4) 2 weeks following injury. However, respiratory function and swallowing function significantly improved thereafter. CPF, FEV1.0, and %VC were significantly correlated with the severity of dysphagia during each period. Conclusions Restrictive ventilatory impairment, poor cough force, and dysphagia are closely related, and the evaluation of respiratory function plays an important role in evaluating dysphagia.
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Affiliation(s)
- Yuki Matsumoto
- Department of Orthopedic Surgery, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
| | - Tetsuo Hayashi
- Department of Orthopedic Surgery, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
- Department of Rehabilitation Medicine, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
| | - Yuichi Fujiwara
- Nursing Department, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
| | - Kensuke Kubota
- Department of Orthopedic Surgery, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
- Department of Rehabilitation Medicine, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
| | - Muneaki Masuda
- Department of Orthopedic Surgery, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
| | - Osamu Kawano
- Department of Orthopedic Surgery, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
| | - Takeshi Maeda
- Department of Orthopedic Surgery, Japan Organization of Occupational Health and Safety, Spinal Injuries Center, Fukuoka, Japan
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10
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Lee KZ. Neuropathology of distinct diaphragm areas following mid-cervical spinal cord contusion in the rat. Spine J 2022; 22:1726-1741. [PMID: 35680014 DOI: 10.1016/j.spinee.2022.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/17/2022] [Accepted: 05/26/2022] [Indexed: 02/03/2023]
Abstract
BACKGROUND The diaphragm is innervated by phrenic motoneurons distributed from the third to fifth cervical spinal cord. The rostral to caudal phrenic motoneuron pool segmentally innervates the ventral, medial, and dorsal diaphragm. PURPOSE The present study was designed to investigate the physiological and transcriptomic mechanism of neuropathology of distinct diaphragm areas following mid-cervical spinal cord injury. STUDY DESIGN In vivo animal study. METHODS Electromyograms and transcriptome of the ventral, medial, and dorsal diaphragm were examined in rats that received cervical laminectomy or mid-cervical spinal cord contusion in the acute (ie, 1-3 days) or subchronic (ie, ∼14 days) injury stages. RESULTS Mid-cervical spinal cord contusion significantly attenuated the inspiratory bursting amplitude of the dorsal diaphragm but not the ventral or medial diaphragm. Moreover, the discharge onset of the dorsal diaphragm was significantly delayed compared with that of the ventral and medial diaphragm in contused rats. Transcriptomic analysis revealed a robust change in gene expression in the ventral diaphragm compared with that in the dorsal diaphragm. Specifically, enrichment analysis of differentially expressed genes demonstrated that the cell cycle and immune response were significantly upregulated, whereas several metabolic pathways were downregulated, in the ventral diaphragm of acutely contused rats. However, no significant Kyoto Encyclopedia of Genes and Genomes pathway was altered in the dorsal diaphragm. CONCLUSIONS These results suggest that mid-cervical spinal cord injury has different impacts on the physiological and transcriptomic responses of distinct diaphragm areas. CLINICAL SIGNIFICANCE Future therapeutic strategies can consider applying different therapies to distinct diaphragm areas following cervical spinal cord injury. Additionally, confirmation of activities across different diaphragm areas may provide a critical reference for the placement of diaphragmatic pacing electrodes.
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Affiliation(s)
- Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan.
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11
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Locke KC, Randelman ML, Hoh DJ, Zholudeva LV, Lane MA. Respiratory plasticity following spinal cord injury: perspectives from mouse to man. Neural Regen Res 2022; 17:2141-2148. [PMID: 35259820 PMCID: PMC9083159 DOI: 10.4103/1673-5374.335839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/18/2021] [Accepted: 10/20/2021] [Indexed: 12/03/2022] Open
Abstract
The study of respiratory plasticity in animal models spans decades. At the bench, researchers use an array of techniques aimed at harnessing the power of plasticity within the central nervous system to restore respiration following spinal cord injury. This field of research is highly clinically relevant. People living with cervical spinal cord injury at or above the level of the phrenic motoneuron pool at spinal levels C3-C5 typically have significant impairments in breathing which may require assisted ventilation. Those who are ventilator dependent are at an increased risk of ventilator-associated co-morbidities and have a drastically reduced life expectancy. Pre-clinical research examining respiratory plasticity in animal models has laid the groundwork for clinical trials. Despite how widely researched this injury is in animal models, relatively few treatments have broken through the preclinical barrier. The three goals of this present review are to define plasticity as it pertains to respiratory function post-spinal cord injury, discuss plasticity models of spinal cord injury used in research, and explore the shift from preclinical to clinical research. By investigating current targets of respiratory plasticity research, we hope to illuminate preclinical work that can influence future clinical investigations and the advancement of treatments for spinal cord injury.
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Affiliation(s)
- Katherine C. Locke
- Department of Neurobiology & Anatomy, Drexel University, Philadelphia, PA, USA
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
| | - Margo L. Randelman
- Department of Neurobiology & Anatomy, Drexel University, Philadelphia, PA, USA
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
| | - Daniel J. Hoh
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, FL, USA
| | - Lyandysha V. Zholudeva
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
- Cardiovascular Disease, Gladstone Institutes, San Francisco, CA, USA
| | - Michael A. Lane
- Department of Neurobiology & Anatomy, Drexel University, Philadelphia, PA, USA
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
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12
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Allen LL, Nichols NL, Asa ZA, Emery AT, Ciesla MC, Santiago JV, Holland AE, Mitchell GS, Gonzalez-Rothi EJ. Phrenic motor neuron survival below cervical spinal cord hemisection. Exp Neurol 2021; 346:113832. [PMID: 34363808 PMCID: PMC9065093 DOI: 10.1016/j.expneurol.2021.113832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 02/04/2023]
Abstract
Cervical spinal cord injury (cSCI) severs bulbospinal projections to respiratory motor neurons, paralyzing respiratory muscles below the injury. C2 spinal hemisection (C2Hx) is a model of cSCI often used to study spontaneous and induced plasticity and breathing recovery post-injury. One key assumption is that C2Hx dennervates motor neurons below the injury, but does not affect their survival. However, a recent study reported substantial bilateral motor neuron death caudal to C2Hx. Since phrenic motor neuron (PMN) death following C2Hx would have profound implications for therapeutic strategies designed to target spared neural circuits, we tested the hypothesis that C2Hx minimally impacts PMN survival. Using improved retrograde tracing methods, we observed no loss of PMNs at 2- or 8-weeks post-C2Hx. We also observed no injury-related differences in ChAT or NeuN immunolabeling within labelled PMNs. Although we found no evidence of PMN loss following C2Hx, we cannot rule out neuronal loss in other motor pools. These findings address an essential prerequisite for studies that utilize C2Hx as a model to explore strategies for inducing plasticity and/or regeneration within the phrenic motor system, as they provide important insights into the viability of phrenic motor neurons as therapeutic targets after high cervical injury.
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Affiliation(s)
- Latoya L Allen
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Zachary A Asa
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | | | - Marissa C Ciesla
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Juliet V Santiago
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Ashley E Holland
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Elisa J Gonzalez-Rothi
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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13
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Randelman M, Zholudeva LV, Vinit S, Lane MA. Respiratory Training and Plasticity After Cervical Spinal Cord Injury. Front Cell Neurosci 2021; 15:700821. [PMID: 34621156 PMCID: PMC8490715 DOI: 10.3389/fncel.2021.700821] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/11/2021] [Indexed: 12/30/2022] Open
Abstract
While spinal cord injuries (SCIs) result in a vast array of functional deficits, many of which are life threatening, the majority of SCIs are anatomically incomplete. Spared neural pathways contribute to functional and anatomical neuroplasticity that can occur spontaneously, or can be harnessed using rehabilitative, electrophysiological, or pharmacological strategies. With a focus on respiratory networks that are affected by cervical level SCI, the present review summarizes how non-invasive respiratory treatments can be used to harness this neuroplastic potential and enhance long-term recovery. Specific attention is given to "respiratory training" strategies currently used clinically (e.g., strength training) and those being developed through pre-clinical and early clinical testing [e.g., intermittent chemical stimulation via altering inhaled oxygen (hypoxia) or carbon dioxide stimulation]. Consideration is also given to the effect of training on non-respiratory (e.g., locomotor) networks. This review highlights advances in this area of pre-clinical and translational research, with insight into future directions for enhancing plasticity and improving functional outcomes after SCI.
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Affiliation(s)
- Margo Randelman
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Lyandysha V Zholudeva
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States.,Gladstone Institutes, San Francisco, CA, United States
| | - Stéphane Vinit
- INSERM, END-ICAP, Université Paris-Saclay, UVSQ, Versailles, France
| | - Michael A Lane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
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14
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Sunshine MD, Fuller DD. Automated Classification of Whole Body Plethysmography Waveforms to Quantify Breathing Patterns. Front Physiol 2021; 12:690265. [PMID: 34489719 PMCID: PMC8417563 DOI: 10.3389/fphys.2021.690265] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/30/2021] [Indexed: 12/19/2022] Open
Abstract
Whole body plethysmography (WBP) monitors respiratory rate and depth but conventional analysis fails to capture the diversity of waveforms. Our first purpose was to develop a waveform cluster analysis method for quantifying dynamic changes in respiratory waveforms. WBP data, from adult Sprague-Dawley rats, were sorted into time domains and principle component analysis was used for hierarchical clustering. The clustering method effectively sorted waveforms into categories including sniffing, tidal breaths of varying duration, and augmented breaths (sighs). We next used this clustering method to quantify breathing after opioid (fentanyl) overdose and treatment with ampakine CX1942, an allosteric modulator of AMPA receptors. Fentanyl caused the expected decrease in breathing, but our cluster analysis revealed changes in the temporal appearance of inspiratory efforts. Ampakine CX1942 treatment shifted respiratory waveforms toward baseline values. We conclude that this method allows for rapid assessment of breathing patterns across extended data recordings. Expanding analyses to include larger portions of recorded WBP data may provide insight on how breathing is affected by disease or therapy.
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Affiliation(s)
- Michael D Sunshine
- Rehabilitation Science Ph.D. Program, University of Florida, Gainesville, FL, United States.,Department of Physical Therapy, University of Florida, Gainesville, FL, United States.,Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.,McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States.,Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, United States.,McKnight Brain Institute, University of Florida, Gainesville, FL, United States
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15
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Lee KZ, Liou LM, Vinit S. Diaphragm Motor-Evoked Potential Induced by Cervical Magnetic Stimulation following Cervical Spinal Cord Contusion in the Rat. J Neurotrauma 2021; 38:2122-2140. [PMID: 33899506 DOI: 10.1089/neu.2021.0080] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cervical spinal injury is typically associated with respiratory impairments due to damage to bulbospinal respiratory pathways and phrenic motoneurons. Magnetic stimulation is a non-invasive approach for the evaluation and modulation of the nervous system. The present study was designed to examine whether cervical magnetic stimulation can be applied to evaluate diaphragmatic motor outputs in a pre-clinical rat model of cervical spinal injury. The bilateral diaphragm was monitored in anesthetized rats using electromyogram at the acute, subchronic, and chronic stages following left mid-cervical contusion. The center of a figure-of-eight coil was placed 20 mm caudal to bregma to stimulate the cervical spinal cord. The results demonstrated that a single magnetic stimulation can evoke significant motor-evoked potentials in the diaphragms of uninjured animals when the animal's head was placed 30 mm right or left from the center of the coil. The spontaneous bursting of the diaphragm was significantly attenuated by contusion injury at all-time-points post-injury. However, the threshold of the diaphragmatic motor-evoked potential was reduced, and the amplitude of the diaphragmatic motor-evoked potential was enhanced in response to cervical magnetic stimulation at the acute injury stage. Moreover, the motor-evoked potentials of the bilateral diaphragm in animals with contusions were generally larger when the coil was placed at the left spinal cord at the subchronic and chronic injury stages. These results suggested that cervical magnetic stimulation can be used to examine the excitability of phrenic motor outputs post-injury, and magnetic stimulation applied more laterally may be more effective for triggering diaphragmatic motor-evoked potentials.
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Affiliation(s)
- Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Biomedical Science and Environmental Biology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Li-Min Liou
- Department of Neurology, Kaohsiung Medical University Hospital, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Neurology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Stéphane Vinit
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, Versailles, France
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16
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Wu X, Xu X, Liu Q, Ding J, Liu J, Huang Z, Huang Z, Wu X, Li R, Yang Z, Jiang H, Liu J, Zhu Q. Unilateral cervical spinal cord injury induces bone loss and metabolic changes in non-human primates ( Macaca fascicularis). J Orthop Translat 2021; 29:113-122. [PMID: 34178602 PMCID: PMC8193057 DOI: 10.1016/j.jot.2021.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 11/14/2020] [Accepted: 03/01/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND/OBJECTIVE The deleterious effects of chronic spinal cord injury (SCI) on the skeleton in rats, especially the lower extremities, has been proved previously. However, the long-term skeletal changes after SCI in non-human primates (NHP) have been scarcely studied. This study aimed to evaluate the bone loss in limbs and vertebrae and the bone metabolic changes in NHP after unilateral cervical spinal cord contusion injury. METHODS Twelve Macaca fascicularis were randomly divided into the SCI (n=8) and the Sham (n=4) groups. The SCI models were established using hemi-contusion cervical spinal cord injury on fifth cervical vertebra (C5), and were further evaluated by histological staining and neurophysiological monitoring. Changes of bone microstructures, bone biomechanics, and bone metabolism markers were assessed by micro-CT, micro-FEA and serological kit. RESULTS The NHP hemi-contusion cervical SCI model led to consistent unilateral limb dysfunction and potential plasticity in the face of loss of spinal cord. Furthermore, the cancellous bone mass of ipsilateral humerus and radius decreased significantly compared to the contralateral side. The bone volume fraction of humerus and radius were 17.2% and 20.1% on the ipsilateral while 29.0% and 30.1% on the contralateral respectively. Similarly, the thickness of the cortical bone in the ipsilateral forelimbs was significantly decreased, as well as the bone strength of the ipsilateral forelimbs. These changes were accompanied by diminished concentration of osteocalcin and total procollagen type 1 N-terminal propeptide (t-P1NP) as well as increased level of β-C-terminal cross-linking telopeptide of type 1collagen (β-CTX) in serological testing. CONCLUSIONS The present study demonstrated that hemi-SCI induced loss of bone mass and compromised biomechanical performance in ipsilateral forelimbs, which could be indicated by both muscle atrophy and serological changes of bone metabolism, and associated with a consistent loss of large-diameter cells of sensory neurons in the dorsal root ganglia. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE Our study, for the first time, demonstrated the bone loss in limbs and vertebrae as well as the bone metabolic changes in non-human primates after unilateral spinal cord injury (SCI). This may help to elucidate the role of muscle atrophy, serological changes and loss of sensory neurons in the mechanisms of SCI-induced osteoporosis, which would be definitely better compared with rodent models.
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Affiliation(s)
- Xiuhua Wu
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiaolin Xu
- Department of Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Qi Liu
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Jianyang Ding
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Junhao Liu
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhiping Huang
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Zucheng Huang
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiaoliang Wu
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Rong Li
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhou Yang
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Hui Jiang
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, Vancouver, BritishColumbia, Canada
| | - Qingan Zhu
- Division of Spine Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
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17
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Gonzalez-Rothi EJ, Lee KZ. Intermittent hypoxia and respiratory recovery in pre-clinical rodent models of incomplete cervical spinal cord injury. Exp Neurol 2021; 342:113751. [PMID: 33974878 DOI: 10.1016/j.expneurol.2021.113751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/24/2021] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
Impaired respiratory function is a common and devastating consequence of cervical spinal cord injury. Accordingly, the development of safe and effective treatments to restore breathing function is critical. Acute intermittent hypoxia has emerged as a promising therapeutic strategy to treat respiratory insufficiency in individuals with spinal cord injury. Since the original report by Bach and Mitchell (1996) concerning long-term facilitation of phrenic motor output elicited by brief, episodic exposure to reduced oxygen, a series of studies in animal models have led to the realization that acute intermittent hypoxia may have tremendous potential for inducing neuroplasticity and functional recovery in the injured spinal cord. Advances in our understanding of the neurobiology of acute intermittent hypoxia have prompted us to begin to explore its effects in human clinical studies. Here, we review the basic neurobiology of the control of breathing and the pathophysiology and respiratory consequences of two common experimental models of incomplete cervical spinal cord injury (i.e., high cervical hemisection and mid-cervical contusion). We then discuss the impact of acute intermittent hypoxia on respiratory motor function in these models: work that has laid the foundation for translation of this promising therapeutic strategy to clinical populations. Lastly, we examine the limitations of these animal models and intermittent hypoxia and discuss how future work in animal models may further advance the translation and therapeutic efficacy of this treatment.
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Affiliation(s)
- Elisa J Gonzalez-Rothi
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan.
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18
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Cheng L, Sami A, Ghosh B, Urban MW, Heinsinger NM, Liang SS, Smith GM, Wright MC, Li S, Lepore AC. LAR inhibitory peptide promotes recovery of diaphragm function and multiple forms of respiratory neural circuit plasticity after cervical spinal cord injury. Neurobiol Dis 2020; 147:105153. [PMID: 33127470 PMCID: PMC7726004 DOI: 10.1016/j.nbd.2020.105153] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/14/2020] [Accepted: 10/25/2020] [Indexed: 12/18/2022] Open
Abstract
Chondroitin sulfate proteoglycans (CSPGs), up-regulated in and around the lesion after traumatic spinal cord injury (SCI), are key extracellular matrix inhibitory molecules that limit axon growth and consequent recovery of function. CSPG-mediated inhibition occurs via interactions with axonal receptors, including leukocyte common antigen- related (LAR) phosphatase. We tested the effects of a novel LAR inhibitory peptide in rats after hemisection at cervical level 2, a SCI model in which bulbospinal inspiratory neural circuitry originating in the medullary rostral ventral respiratory group (rVRG) becomes disconnected from phrenic motor neuron (PhMN) targets in cervical spinal cord, resulting in persistent partial-to-complete diaphragm paralysis. LAR peptide was delivered by a soaked gelfoam, which was placed directly over the injury site immediately after C2 hemisection and replaced at 1 week post-injury. Axotomized rVRG axons originating in ipsilateral medulla or spared rVRG fibers originating in contralateral medulla were separately assessed by anterograde tracing via AAV2-mCherry injection into rVRG. At 8 weeks post-hemisection, LAR peptide significantly improved ipsilateral hemidiaphragm function, as assessed in vivo with electromyography recordings. LAR peptide promoted robust regeneration of ipsilateral-originating rVRG axons into and through the lesion site and into intact caudal spinal cord to reach PhMNs located at C3-C5 levels. Furthermore, regenerating rVRG axons re-established putative monosynaptic connections with their PhMNs targets. In addition, LAR peptide stimulated robust sprouting of both modulatory serotonergic axons and contralateral-originating rVRG fibers within the PhMN pool ipsilateral/ caudal to the hemisection. Our study demonstrates that targeting LAR-based axon growth inhibition promotes multiple forms of respiratory neural circuit plasticity and provides a new peptide-based therapeutic strategy to ameliorate the devastating respiratory consequences of SCI.
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Affiliation(s)
- Lan Cheng
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - Armin Sami
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - Mark W Urban
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - Nicolette M Heinsinger
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - Sophia S Liang
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - George M Smith
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140-5104, United States of America
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, PA 19038, United States of America
| | - Shuxin Li
- Department of Anatomy and Cell Biology, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140-5104, United States of America
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, United States of America.
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19
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Smuder AJ, Turner SM, Schuster CM, Morton AB, Hinkley JM, Fuller DD. Hyperbaric Oxygen Treatment Following Mid-Cervical Spinal Cord Injury Preserves Diaphragm Muscle Function. Int J Mol Sci 2020; 21:ijms21197219. [PMID: 33007822 PMCID: PMC7582297 DOI: 10.3390/ijms21197219] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/17/2022] Open
Abstract
Oxidative damage to the diaphragm as a result of cervical spinal cord injury (SCI) promotes muscle atrophy and weakness. Respiratory insufficiency is the leading cause of morbidity and mortality in cervical spinal cord injury (SCI) patients, emphasizing the need for strategies to maintain diaphragm function. Hyperbaric oxygen (HBO) increases the amount of oxygen dissolved into the blood, elevating the delivery of oxygen to skeletal muscle and reactive oxygen species (ROS) generation. It is proposed that enhanced ROS production due to HBO treatment stimulates adaptations to diaphragm oxidative capacity, resulting in overall reductions in oxidative stress and inflammation. Therefore, we tested the hypothesis that exposure to HBO therapy acutely following SCI would reduce oxidative damage to the diaphragm muscle, preserving muscle fiber size and contractility. Our results demonstrated that lateral contusion injury at C3/4 results in a significant reduction in diaphragm muscle-specific force production and fiber cross-sectional area, which was associated with augmented mitochondrial hydrogen peroxide emission and a reduced mitochondrial respiratory control ratio. In contrast, rats that underwent SCI followed by HBO exposure consisting of 1 h of 100% oxygen at 3 atmospheres absolute (ATA) delivered for 10 consecutive days demonstrated an improvement in diaphragm-specific force production, and an attenuation of fiber atrophy, mitochondrial dysfunction and ROS production. These beneficial adaptations in the diaphragm were related to HBO-induced increases in antioxidant capacity and a reduction in atrogene expression. These findings suggest that HBO therapy may be an effective adjunctive therapy to promote respiratory health following cervical SCI.
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Affiliation(s)
- Ashley J. Smuder
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
- Breathing Research and Therapeutics, University of Florida, Gainesville, FL 32610, USA;
- Correspondence:
| | - Sara M. Turner
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
| | - Cassandra M. Schuster
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
| | - Aaron B. Morton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
| | - J. Matthew Hinkley
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
| | - David D. Fuller
- Breathing Research and Therapeutics, University of Florida, Gainesville, FL 32610, USA;
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
- McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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Lukáčová N, Hricová L, Kisucká A, Papcunová Š, Bimbová K, Bačová M, Pavel J, Marsala M, Vanický I, Dzurjašková Z, Matéffy S, Lukáčová V, Stropkovská A, Gálik J. Is Innervation of the Neuromuscular Junction at the Diaphragm Modulated by sGC/cGMP Signaling? Front Physiol 2020; 11:700. [PMID: 32655417 PMCID: PMC7324717 DOI: 10.3389/fphys.2020.00700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 05/28/2020] [Indexed: 11/15/2022] Open
Abstract
We previously reported NO/sGC signaling in the upper respiratory pathway, receiving input from the respiratory neurons of the brainstem to phrenic motoneurons in the C3–C6 spinal cord. In order to assess whether innervation of the neuromuscular junction (NMJ) at the diaphragm is modulated by sGC/cGMP signaling, we performed unilateral 8-day continuous ligation of the phrenic nerve in rats. We examined sGCβ1 within the lower bulbospinal pathway (phrenic motoneurons, phrenic nerves and NMJs at the diaphragm) and the cGMP level in the contra- and ipsilateral hemidiaphragm. Additionally, we characterized the extent of phrenic nerve axonal degeneration and denervation at diaphragm NMJs. The results of our study show that continuous 8-day phrenic nerve ligation caused a marked increase in sGCβ1 (immunoreactivity and the protein level) in the ipsilateral phrenic motor pool. However, the protein sGCβ1 level in the phrenic nerve below its ligation and the cGMP level in the ipsilateral hemidiaphragm were evidently decreased. Using confocal analysis we discovered a reduction in sGCβ1-IR boutons/synaptic vesicles at the ipsilateral MNJs. These findings are consistent with the marked axonal loss (∼47%) and significant NMJs degeneration in the ipsilateral diaphragm muscle. The remarkable unilateral decrease in cGMP level in the diaphragm and the failure of EMG recordings in the ipsilateral hemidiaphragm muscle can be attributed to the fact that sGC is involved in transmitter release at the diaphragm NMJs via the sGC-cGMP pathway.
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Affiliation(s)
- Nadežda Lukáčová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - L'udmila Hricová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Alexandra Kisucká
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Štefánia Papcunová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Katarína Bimbová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Mária Bačová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Jaroslav Pavel
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Martin Marsala
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia.,Neuroregeneration Laboratory, Department of Anesthesiology, University of California, San Diego, La Jolla, CA, United States
| | - Ivo Vanický
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Zuzana Dzurjašková
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Stanislav Matéffy
- Diagnostic Center of Pathology in Prešov, Alpha Medical, s.r.o., Martin, Slovakia
| | - Viktória Lukáčová
- Faculty of Economics, Technical University of Košice, Košice, Slovakia
| | - Andrea Stropkovská
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Ján Gálik
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
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21
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Fogarty MJ, Sieck GC. Spinal cord injury and diaphragm neuromotor control. Expert Rev Respir Med 2020; 14:453-464. [PMID: 32077350 PMCID: PMC7176525 DOI: 10.1080/17476348.2020.1732822] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/18/2020] [Indexed: 12/22/2022]
Abstract
Introduction: Neuromotor control of diaphragm muscle and the recovery of diaphragm activity following spinal cord injury have been narrowly focused on ventilation. By contrast, the understanding of neuromotor control for non-ventilatory expulsive/straining maneuvers (including coughing, defecation, and parturition) is relatively impoverished. This variety of behaviors are achieved via the recruitment of the diverse array of motor units that comprise the diaphragm muscle.Areas covered: The neuromotor control of ventilatory and non-ventilatory behaviors in health and in the context of spinal cord injury is explored. Particular attention is played to the neuroplasticity of phrenic motor neurons in various models of cervical spinal cord injury.Expert opinion: There is a remarkable paucity in our understanding of neuromotor control of maneuvers in spinal cord injury patients. Dysfunction of these expulsive/straining maneuvers reduces patient quality of life and contributes to severe morbidity and mortality. As spinal cord injury patient life expectancies continue to climb steadily, a nexus of spinal cord injury and age-associated comorbidities are likely to occur. While current research remains concerned only with the minutiae of ventilation, the major functional deficits of this clinical cohort will persist intractably. We posit some future research directions to avoid this scenario.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
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22
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Chan JP, Clune J, Shah SB, Ward SR, Kocsis JD, Mozaffar T, Steward O, Gupta R. Examination of the human motor endplate after brachial plexus injury with two-photon microscopy. Muscle Nerve 2019; 61:390-395. [PMID: 31820462 DOI: 10.1002/mus.26778] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 11/28/2019] [Accepted: 12/03/2019] [Indexed: 12/12/2022]
Abstract
INTRODUCTION After traumatic nerve injury, neuromuscular junction remodeling plays a key role in determining functional outcomes. Immunohistochemical analyses of denervated muscle biopsies may provide valuable prognostic data regarding clinical outcomes to supplement electrodiagnostic studies. METHODS We performed biopsies on nonfunctioning deltoid muscles in two patients after gunshot wounds and visualized the neuromuscular junctions using two-photon microscopy with immunohistochemistry. RESULTS Although the nerves in both patients showed evidence of acute Wallerian degeneration, some of the motor endplates were intact but exhibited significantly decreased surface area and volume. Both patients exhibited substantial recovery of motor function over several weeks postinjury. DISCUSSION Two-photon microscopic assessment of neuromuscular junction integrity and motor endplate morphometry in muscle biopsies provided evidence of partial sparing of muscle innervation. This finding supported the clinical judgment that eventual recovery would occur. With further study, this technique may help to guide operative decisionmaking after traumatic nerve injuries.
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Affiliation(s)
- Justin P Chan
- Department of Orthopaedic Surgery, University of California, Irvine, California
| | - James Clune
- Section of Plastic and Reconstructive Surgery, Yale University School of Medicine, New Haven, Connecticut
| | - Sameer B Shah
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.,Department of Bioengineering, University of California, San Diego, La Jolla, California
| | - Samuel R Ward
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.,Department of Bioengineering, University of California, San Diego, La Jolla, California
| | - Jeffery D Kocsis
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut
| | - Tahseen Mozaffar
- Department of Neurology, University of California, Irvine, Irvine, California
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California, Irvine, Irvine, California
| | - Ranjan Gupta
- Department of Orthopaedic Surgery, University of California, Irvine, California
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23
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Charsar BA, Brinton MA, Locke K, Chen AY, Ghosh B, Urban MW, Komaravolu S, Krishnamurthy K, Smit R, Pasinelli P, Wright MC, Smith GM, Lepore AC. AAV2-BDNF promotes respiratory axon plasticity and recovery of diaphragm function following spinal cord injury. FASEB J 2019; 33:13775-13793. [PMID: 31577916 DOI: 10.1096/fj.201901730r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
More than half of spinal cord injury (SCI) cases occur in the cervical region, leading to respiratory dysfunction due to damaged neural circuitry that controls critically important muscles such as the diaphragm. The C3-C5 spinal cord is the location of phrenic motor neurons (PhMNs) that are responsible for diaphragm activation; PhMNs receive bulbospinal excitatory drive predominately from supraspinal neurons of the rostral ventral respiratory group (rVRG). Cervical SCI results in rVRG axon damage, PhMN denervation, and consequent partial-to-complete paralysis of hemidiaphragm. In a rat model of C2 hemisection SCI, we expressed the axon guidance molecule, brain-derived neurotrophic factor (BDNF), selectively at the location of PhMNs (ipsilateral to lesion) to promote directed growth of rVRG axons toward PhMN targets by performing intraspinal injections of adeno-associated virus serotype 2 (AAV2)-BDNF vector. AAV2-BDNF promoted significant functional diaphragm recovery, as assessed by in vivo electromyography. Within the PhMN pool ipsilateral to injury, AAV2-BDNF robustly increased sprouting of both spared contralateral-originating rVRG axons and serotonergic fibers. Furthermore, AAV2-BDNF significantly increased numbers of putative monosynaptic connections between PhMNs and these sprouting rVRG and serotonergic axons. These findings show that targeting circuit plasticity mechanisms involving the enhancement of synaptic inputs from spared axon populations is a powerful strategy for restoring respiratory function post-SCI.-Charsar, B. A., Brinton, M. A., Locke, K., Chen, A. Y., Ghosh, B., Urban, M. W., Komaravolu, S., Krishnamurthy, K., Smit, R., Pasinelli, P., Wright, M. C., Smith, G. M., Lepore, A. C. AAV2-BDNF promotes respiratory axon plasticity and recovery of diaphragm function following spinal cord injury.
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Affiliation(s)
- Brittany A Charsar
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael A Brinton
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Katherine Locke
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Anna Y Chen
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mark W Urban
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Sreeya Komaravolu
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Karthik Krishnamurthy
- Department of Neuroscience, Jefferson Weinberg Amyotrophic Lateral Sclerosis (ALS) Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Rupert Smit
- Department of Anatomy and Cell Biology, Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Piera Pasinelli
- Department of Neuroscience, Jefferson Weinberg Amyotrophic Lateral Sclerosis (ALS) Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Philadelphia, Pennsylvania, USA
| | - George M Smith
- Department of Anatomy and Cell Biology, Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Long-Distance Axon Regeneration Promotes Recovery of Diaphragmatic Respiratory Function after Spinal Cord Injury. eNeuro 2019; 6:ENEURO.0096-19.2019. [PMID: 31427403 PMCID: PMC6794082 DOI: 10.1523/eneuro.0096-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/11/2019] [Accepted: 06/14/2019] [Indexed: 12/14/2022] Open
Abstract
Compromise in inspiratory breathing following cervical spinal cord injury (SCI) is caused by damage to descending bulbospinal axons originating in the rostral ventral respiratory group (rVRG) and consequent denervation and silencing of phrenic motor neurons (PhMNs) that directly control diaphragm activation. In a rat model of high-cervical hemisection SCI, we performed systemic administration of an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential. PTEN antagonist peptide (PAP4) robustly restored diaphragm function, as determined with electromyography (EMG) recordings in living SCI animals. PAP4 promoted substantial, long-distance regeneration of injured rVRG axons through the lesion and back toward PhMNs located throughout the C3–C5 spinal cord. These regrowing rVRG axons also formed putative excitatory synaptic connections with PhMNs, demonstrating reconnection of rVRG-PhMN-diaphragm circuitry. Lastly, re-lesion through the hemisection site completely ablated functional recovery induced by PAP4. Collectively, our findings demonstrate that axon regeneration in response to systemic PAP4 administration promoted recovery of diaphragmatic respiratory function after cervical SCI.
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25
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Ghosh B, Nong J, Wang Z, Urban MW, Heinsinger NM, Trovillion VA, Wright MC, Lepore AC, Zhong Y. A hydrogel engineered to deliver minocycline locally to the injured cervical spinal cord protects respiratory neural circuitry and preserves diaphragm function. Neurobiol Dis 2019; 127:591-604. [PMID: 31028873 DOI: 10.1016/j.nbd.2019.04.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 04/06/2019] [Accepted: 04/23/2019] [Indexed: 12/13/2022] Open
Abstract
We tested a biomaterial-based approach to preserve the critical phrenic motor circuitry that controls diaphragm function by locally delivering minocycline hydrochloride (MH) following cervical spinal cord injury (SCI). MH is a clinically-available antibiotic and anti-inflammatory drug that targets a broad range of secondary injury mechanisms via its anti-inflammatory, anti-oxidant and anti-apoptotic properties. However, MH is only neuroprotective at high concentrations that cannot be achieved by systemic administration, which limits its clinical efficacy. We have developed a hydrogel-based MH delivery system that can be injected into the intrathecal space for local delivery of high concentrations of MH, without damaging spinal cord tissue. Implantation of MH hydrogel after unilateral level-C4/5 contusion SCI robustly preserved diaphragm function, as assessed by in vivo recordings of compound muscle action potential (CMAP) and electromyography (EMG) amplitudes. MH hydrogel also decreased lesion size and degeneration of cervical motor neuron somata, demonstrating its central neuroprotective effects within the injured cervical spinal cord. Furthermore, MH hydrogel significantly preserved diaphragm innervation by the axons of phrenic motor neurons (PhMNs), as assessed by both detailed neuromuscular junction (NMJ) morphological analysis and retrograde PhMN labeling from the diaphragm using cholera toxin B (CTB). In conclusion, our findings demonstrate that local MH hydrogel delivery to the injured cervical spinal cord is effective in preserving respiratory function after SCI by protecting the important neural circuitry that controls diaphragm activation.
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Affiliation(s)
- Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, 233 S. 10th St., Bluemle Life Sciences Building - Room 245, Philadelphia, PA 19107, United States of America
| | - Jia Nong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Bossone 7-716, Philadelphia, PA 19104, United States of America
| | - Zhicheng Wang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Bossone 7-716, Philadelphia, PA 19104, United States of America
| | - Mark W Urban
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, 233 S. 10th St., Bluemle Life Sciences Building - Room 245, Philadelphia, PA 19107, United States of America
| | - Nicolette M Heinsinger
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, 233 S. 10th St., Bluemle Life Sciences Building - Room 245, Philadelphia, PA 19107, United States of America
| | - Victoria A Trovillion
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, 233 S. 10th St., Bluemle Life Sciences Building - Room 245, Philadelphia, PA 19107, United States of America
| | - Megan C Wright
- Department of Biology, Arcadia University, 450 S Easton Rd, 220 Boyer Hall, Glenside, PA 19038, United States of America
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, 233 S. 10th St., Bluemle Life Sciences Building - Room 245, Philadelphia, PA 19107, United States of America.
| | - Yinghui Zhong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Bossone 7-716, Philadelphia, PA 19104, United States of America.
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26
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Warren PM, Alilain WJ. Plasticity Induced Recovery of Breathing Occurs at Chronic Stages after Cervical Contusion. J Neurotrauma 2019; 36:1985-1999. [PMID: 30565484 DOI: 10.1089/neu.2018.6186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Severe midcervical contusion injury causes profound deficits throughout the respiratory motor system that last from acute to chronic time points post-injury. We use chondroitinase ABC (ChABC) to digest chondroitin sulphate proteoglycans within the extracellular matrix (ECM) surrounding the respiratory system at both acute and chronic time points post-injury to explore whether augmentation of plasticity can recover normal motor function. We demonstrate that, regardless of time post-injury or treatment application, the lesion cavity remains consistent, showing little regeneration or neuroprotection within our model. Through electromyography (EMG) recordings of multiple inspiratory muscles, however, we show that application of the enzyme at chronic time points post-injury initiates the recovery of normal breathing in previously paralyzed respiratory muscles. This reduced the need for compensatory activity throughout the motor system. Application of ChABC at acute time points recovered only modest amounts of respiratory function. To further understand this effect, we assessed the anatomical mechanism of this recovery. Increased EMG activity in previously paralyzed muscles was brought about by activation of spared bulbospinal pathways through the site of injury and/or sprouting of spared serotonergic fibers from the contralateral side of the cord. Accordingly, we demonstrate that alterations to the ECM and augmentation of plasticity at chronic time points post-cervical contusion can cause functional recovery of the respiratory motor system and reveal mechanistic evidence of the pathways that govern this effect.
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Affiliation(s)
- Philippa Mary Warren
- 1 Department of Neurosciences, MetroHealth Medical Centre, Case Western Reserve University, Cleveland, Ohio.,2 King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Guy's Campus, London Bridge, London, United Kingdom
| | - Warren Joseph Alilain
- 1 Department of Neurosciences, MetroHealth Medical Centre, Case Western Reserve University, Cleveland, Ohio.,3 Department of Neuroscience, Spinal Cord and Brain Injury Research Centre, University of Kentucky, Lexington, Kentucky
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27
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Seven YB, Mitchell GS. Mechanisms of compensatory plasticity for respiratory motor neuron death. Respir Physiol Neurobiol 2019; 265:32-39. [PMID: 30625378 DOI: 10.1016/j.resp.2019.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/22/2018] [Accepted: 01/03/2019] [Indexed: 02/06/2023]
Abstract
Respiratory motor neuron death arises from multiple neurodegenerative and traumatic neuromuscular disorders. Despite motor neuron death, compensatory mechanisms minimize its functional impact by harnessing intrinsic mechanisms of compensatory respiratory plasticity. However, the capacity for compensation eventually reaches limits and pathology ensues. Initially, challenges to the system such as increased metabolic demand reveal sub-clinical pathology. With greater motor neuron loss, the eventual result is de-compensation, ventilatory failure, ventilator dependence and then death. In this brief review, we discuss recent advances in our understanding of mechanisms giving rise to compensatory respiratory plasticity in response to respiratory motor neuron death including: 1) increased central respiratory drive, 2) plasticity in synapses on spared phrenic motor neurons, 3) enhanced neuromuscular transmission and 4) shifts in respiratory muscle utilization from more affected to less affected motor pools. Some of these compensatory mechanisms may prolong breathing function, but hasten the demise of surviving motor neurons. Improved understanding of these mechanisms and their impact on survival of spared motor neurons will guide future efforts to develop therapeutic interventions that preserve respiratory function with neuromuscular injury/disease.
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Affiliation(s)
- Yasin B Seven
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA
| | - Gordon S Mitchell
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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28
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Goulão M, Ghosh B, Urban MW, Sahu M, Mercogliano C, Charsar BA, Komaravolu S, Block CG, Smith GM, Wright MC, Lepore AC. Astrocyte progenitor transplantation promotes regeneration of bulbospinal respiratory axons, recovery of diaphragm function, and a reduced macrophage response following cervical spinal cord injury. Glia 2018; 67:452-466. [PMID: 30548313 DOI: 10.1002/glia.23555] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 09/10/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023]
Abstract
Stem/progenitor cell transplantation delivery of astrocytes is a potentially powerful strategy for spinal cord injury (SCI). Axon extension into SCI lesions that occur spontaneously or in response to experimental manipulations is often observed along endogenous astrocyte "bridges," suggesting that augmenting this response via astrocyte lineage transplantation can enhance axon regrowth. Given the importance of respiratory dysfunction post-SCI, we transplanted glial-restricted precursors (GRPs)-a class of lineage-restricted astrocyte progenitors-into the C2 hemisection model and evaluated effects on diaphragm function and the growth response of descending rostral ventral respiratory group (rVRG) axons that innervate phrenic motor neurons (PhMNs). GRPs survived long term and efficiently differentiated into astrocytes in injured spinal cord. GRPs promoted significant recovery of diaphragm electromyography amplitudes and stimulated robust regeneration of injured rVRG axons. Although rVRG fibers extended across the lesion, no regrowing axons re-entered caudal spinal cord to reinnervate PhMNs, suggesting that this regeneration response-although impressive-was not responsible for recovery. Within ipsilateral C3-5 ventral horn (PhMN location), GRPs induced substantial sprouting of spared fibers originating in contralateral rVRG and 5-HT axons that are important for regulating PhMN excitability; this sprouting was likely involved in functional effects of GRPs. Finally, GRPs reduced the macrophage response (which plays a key role in inducing axon retraction and limiting regrowth) both within the hemisection and at intact caudal spinal cord surrounding PhMNs. These findings demonstrate that astrocyte progenitor transplantation promotes significant plasticity of rVRG-PhMN circuitry and restoration of diaphragm function and suggest that these effects may be in part through immunomodulation.
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Affiliation(s)
- Miguel Goulão
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania.,Life and Health Sciences Research Institute (ICVS), School of Medicine, ICVS/3B's - PT Government Associate Laborator, University of Minho, Braga, Portugal
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Mark W Urban
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Malya Sahu
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christina Mercogliano
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Brittany A Charsar
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sreeya Komaravolu
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Cole G Block
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - George M Smith
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, Pennsylvania
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
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Khurram OU, Fogarty MJ, Rana S, Vang P, Sieck GC, Mantilla CB. Diaphragm muscle function following midcervical contusion injury in rats. J Appl Physiol (1985) 2018; 126:221-230. [PMID: 30236045 DOI: 10.1152/japplphysiol.00481.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Midcervical spinal cord contusion injury results in tissue damage, disruption of spinal pathways, and motor neuron loss. Unilateral C4 contusion results in loss of 40%-50% of phrenic motor neurons ipsilateral to the injury (~25% of the total phrenic motor neuron pool). Over time after unilateral C4 contusion injury, diaphragm muscle (DIAm) electromyogram activity increases both contralateral and ipsilateral to the side of injury in rats, suggesting compensation because of increased activation of the surviving motor neurons. However, the impact of contusion injury on DIAm force generation is less clear. Transdiaphragmatic pressure (Pdi) was measured across motor behaviors over time after unilateral C4 contusion injury in adult male Sprague-Dawley rats. Maximum Pdi (Pdimax) was elicited by bilateral phrenic nerve stimulation at 7 days postinjury. We hypothesized that Pdimax is reduced following unilateral C4 contusion injury, whereas ventilatory behaviors of the DIAm are unimpaired. In support of our hypothesis, Pdimax was reduced by ~25% after unilateral C4 contusion, consistent with the extent of phrenic motor neuron loss following contusion injury. One day after contusion injury, the Pdi amplitude during airway occlusion was reduced from ~30 to ~20 cmH2O, but this reduction was completely reversed by 7 days postinjury. Ventilatory behaviors (~10 cmH2O), DIAm-specific force, and muscle fiber cross-sectional area did not differ between the laminectomy and contusion groups. These results indicate that the large reserve capacity for DIAm force generation allows for higher-force motor behaviors to be accomplished despite motor neuron loss, likely reflecting changes in motor unit recruitment. NEW & NOTEWORTHY Respiratory muscles such as the diaphragm generate the pressures necessary to accomplish a variety of motor behaviors ranging from ventilation to near-maximal expulsive behaviors. However, the impact of contusion injury on diaphragm pressure generation across behaviors is not clear. The present study shows that contusion injury impairs maximal pressure generation while preserving the ability of the diaphragm to accomplish lower-force motor behaviors, likely reflecting changes in diaphragm motor unit recruitment.
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Affiliation(s)
- Obaid U Khurram
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland , St. Lucia, QLD , Australia
| | - Sabhya Rana
- Department of Neurobiology of Disease, Mayo Clinic , Rochester, Minnesota
| | - Pangdra Vang
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
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Local BDNF Delivery to the Injured Cervical Spinal Cord using an Engineered Hydrogel Enhances Diaphragmatic Respiratory Function. J Neurosci 2018; 38:5982-5995. [PMID: 29891731 DOI: 10.1523/jneurosci.3084-17.2018] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 02/07/2023] Open
Abstract
We developed an innovative biomaterial-based approach to repair the critical neural circuitry that controls diaphragm activation by locally delivering brain-derived neurotrophic factor (BDNF) to injured cervical spinal cord. BDNF can be used to restore respiratory function via a number of potential repair mechanisms; however, widespread BDNF biodistribution resulting from delivery methods such as systemic injection or lumbar puncture can lead to inefficient drug delivery and adverse side effects. As a viable alternative, we developed a novel hydrogel-based system loaded with polysaccharide-BDNF particles self-assembled by electrostatic interactions that can be safely implanted in the intrathecal space for achieving local BDNF delivery with controlled dosing and duration. Implantation of BDNF hydrogel after C4/C5 contusion-type spinal cord injury (SCI) in female rats robustly preserved diaphragm function, as assessed by in vivo recordings of compound muscle action potential and electromyography amplitudes. However, BDNF hydrogel did not decrease lesion size or degeneration of cervical motor neuron soma, suggesting that its therapeutic mechanism of action was not neuroprotection within spinal cord. Interestingly, BDNF hydrogel significantly preserved diaphragm innervation by phrenic motor neurons (PhMNs), as assessed by detailed neuromuscular junction morphological analysis and retrograde PhMN labeling from diaphragm using cholera toxin B. Furthermore, BDNF hydrogel enhanced the serotonergic axon innervation of PhMNs that plays an important role in modulating PhMN excitability. Our findings demonstrate that local BDNF hydrogel delivery is a robustly effective and safe strategy to restore diaphragm function after SCI. In addition, we demonstrate novel therapeutic mechanisms by which BDNF can repair respiratory neural circuitry.SIGNIFICANCE STATEMENT Respiratory compromise is a leading cause of morbidity and mortality following traumatic spinal cord injury (SCI). We used an innovative biomaterial-based drug delivery system in the form of a hydrogel that can be safely injected into the intrathecal space for achieving local delivery of brain-derived neurotrophic factor (BDNF) with controlled dosing and duration, while avoiding side effects associated with other delivery methods. In a clinically relevant rat model of cervical contusion-type SCI, BDNF hydrogel robustly and persistently improved diaphragmatic respiratory function by enhancing phrenic motor neuron (PhMN) innervation of the diaphragm neuromuscular junction and by increasing serotonergic innervation of PhMNs in ventral horn of the cervical spinal cord. These exciting findings demonstrate that local BDNF hydrogel delivery is a safe and robustly effective strategy to maintain respiratory function after cervical SCI.
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Falnikar A, Stratton J, Lin R, Andrews CE, Tyburski A, Trovillion VA, Gottschalk C, Ghosh B, Iacovitti L, Elliott MB, Lepore AC. Differential Response in Novel Stem Cell Niches of the Brain after Cervical Spinal Cord Injury and Traumatic Brain Injury. J Neurotrauma 2018; 35:2195-2207. [PMID: 29471717 DOI: 10.1089/neu.2017.5497] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Populations of neural stem cells (NSCs) reside in a number of defined niches in the adult central nervous system (CNS) where they continually give rise to mature cell types throughout life, including newly born neurons. In addition to the prototypical niches of the subventricular zone (SVZ) and subgranular zone (SGZ) of the hippocampal dentate gyrus, novel stem cell niches that are also neurogenic have recently been identified in multiple midline structures, including circumventricular organs (CVOs) of the brain. These resident NSCs serve as a homeostatic source of new neurons and glial cells under intact physiological conditions. Importantly, they may also have the potential for reparative processes in pathological states such as traumatic spinal cord injury (SCI) and traumatic brain injury (TBI). As the response in these novel CVO stem cell niches has been characterized after stroke but not following SCI or TBI, we quantitatively assessed cell proliferation and the neuronal and glial lineage fate of resident NSCs in three CVO nuclei-area postrema (AP), median eminence (ME), and subfornical organ (SFO) -in rat models of cervical contusion-type SCI and controlled cortical impact (CCI)-induced TBI. Using bromodeoxyuridine (BrdU) labeling of proliferating cells, we find that TBI significantly enhanced proliferation in AP, ME, and SFO, whereas cervical SCI had no effects at early or chronic time-points post-injury. In addition, SCI did not alter NSC differentiation profile into doublecortin-positive neuroblasts, GFAP-expressing astrocytes, or Olig2-labeled cells of the oligodendrocyte lineage within AP, ME, or SFO at both time-points. In contrast, CCI induced a pronounced increase in Sox2- and doublecortin-labeled cells in the AP and Iba1-labeled microglia in the SFO. Lastly, plasma derived from CCI animals significantly increased NSC expansion in an in vitro neurosphere assay, whereas plasma from SCI animals did not exert such an effect, suggesting that signaling factors present in blood may be relevant to stimulating CVO niches after CNS injury and may explain the differential in vivo effects of SCI and TBI on the novel stem cell niches.
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Affiliation(s)
- Aditi Falnikar
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Jarred Stratton
- 2 Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Ruihe Lin
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Carrie E Andrews
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Ashley Tyburski
- 2 Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Victoria A Trovillion
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Chelsea Gottschalk
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Biswarup Ghosh
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Lorraine Iacovitti
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Melanie B Elliott
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania.,2 Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Angelo C Lepore
- 1 Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University , Philadelphia, Pennsylvania
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Warren PM, Campanaro C, Jacono FJ, Alilain WJ. Mid-cervical spinal cord contusion causes robust deficits in respiratory parameters and pattern variability. Exp Neurol 2018; 306:122-131. [PMID: 29653187 PMCID: PMC6333202 DOI: 10.1016/j.expneurol.2018.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/24/2018] [Accepted: 04/06/2018] [Indexed: 02/08/2023]
Abstract
Mid-cervical spinal cord contusion disrupts both the pathways and motoneurons vital to the activity of inspiratory muscles. The present study was designed to determine if a rat contusion model could result in a measurable deficit to both ventilatory and respiratory motor function under “normal” breathing conditions at acute to chronic stages post trauma. Through whole body plethysmography and electromyography we assessed respiratory output from three days to twelve weeks after a cervical level 3 (C3) contusion. Contused animals showed significant deficits in both tidal and minute volumes which were sustained from acute to chronic time points. We also examined the degree to which the contusion injury impacted ventilatory pattern variability through assessment of Mutual Information and Sample Entropy. Mid-cervical contusion significantly and robustly decreased the variability of ventilatory patterns. The enduring deficit to the respiratory motor system caused by contusion was further confirmed through electromyography recordings in multiple respiratory muscles. When isolated via a lesion, these contused pathways were insufficient to maintain respiratory activity at all time points post injury. Collectively these data illustrate that, counter to the prevailing literature, a profound and lasting ventilatory and respiratory motor deficit may be modelled and measured through multiple physiological assessments at all time points after cervical contusion injury.
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Affiliation(s)
- Philippa M Warren
- Department of Neurosciences, MetroHealth Medical Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Cara Campanaro
- Division of Pulmonary Critical Care and Sleep Medicine and Louis Stokes VA Medical Center, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Frank J Jacono
- Division of Pulmonary Critical Care and Sleep Medicine and Louis Stokes VA Medical Center, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Warren J Alilain
- Department of Neurosciences, MetroHealth Medical Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Spinal Cord and Brain Injury Research Centre, University of Kentucky, Lexington, KY 40536, USA.
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Vandeweerd JM, Hontoir F, De Knoop A, De Swert K, Nicaise C. Retrograde Neuroanatomical Tracing of Phrenic Motor Neurons in Mice. J Vis Exp 2018. [PMID: 29553523 DOI: 10.3791/56758] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic nerves innervating the respiratory diaphragm. In spinal cord slices, phrenic motor neurons cannot be identified from other motor neurons on morphological or biochemical criteria. We provide the description of procedures for visualizing phrenic motor neuron cell bodies in mice, following intrapleural injections of cholera toxin subunit beta (CTB) conjugated to a fluorophore. This fluorescent neuroanatomical tracer has the ability to be caught up at the diaphragm neuromuscular junction, be carried retrogradely along the phrenic axons and reach the phrenic cell bodies. Two methodological approaches of intrapleural CTB delivery are compared: transdiaphragmatic versus transthoracic injections. Both approaches are successful and result in similar number of CTB-labeled phrenic motor neurons. In conclusion, these techniques can be applied to visualize or quantify the phrenic motor neurons in various experimental studies such as those focused on the diaphragm-phrenic circuitry.
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Lujan HL, Tonson A, Wiseman RW, DiCarlo SE. Chronic, complete cervical 6-7 cord transection: distinct autonomic and cardiac deficits. J Appl Physiol (1985) 2018; 124:1471-1482. [PMID: 29470149 DOI: 10.1152/japplphysiol.01104.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spinal cord injury (SCI) resulting in tetraplegia is a devastating, life-changing insult causing paralysis and sensory impairment as well as distinct autonomic dysfunction that triggers compromised cardiovascular, bowel, bladder, and sexual activity. Life becomes a battle for independence as even routine bodily functions and the smallest activity of daily living become major challenges. Accordingly, there is a critical need for a chronic preclinical model of tetraplegia. This report addresses this critical need by comparing, for the first time, resting-, reflex-, and stress-induced cardiovascular, autonomic, and hormonal responses each week for 4 wk in 12 sham-operated intact rats and 12 rats with chronic, complete C6-7 spinal cord transection. Loss of supraspinal control to all sympathetic preganglionic neurons projecting to the heart and vasculature resulted in a profound bradycardia and hypotension, reduced cardiac sympathetic and parasympathetic tonus, reduced reflex- and stress-induced sympathetic responses, and reduced sympathetic support of blood pressure as well as enhanced reliance on angiotensin to maintain arterial blood pressure. Histological examination of the nucleus ambiguus and stellate ganglia supports the profound and distinct autonomic and cardiac deficits and reliance on angiotensin to maintain cardiovascular stability following chronic, complete cervical6-7 cord transection. NEW & NOTEWORTHY For the first time, resting-, reflex-, and stress-induced cardiovascular, autonomic, and hormonal responses were studied in rats with chronic, complete C6-7 cord transection. Loss of supraspinal control of all sympathetic preganglionic neurons reduced cardiac sympathetic and parasympathetic tonus, reflex and stress-induced sympathetic responses, and sympathetic support of blood pressure as well as enhanced reliance on angiotensin to maintain arterial blood pressure. Histological examination supports the distinct deficits associated with cervical cord injury.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
| | - Anne Tonson
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
| | - Robert W Wiseman
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
| | - Stephen E DiCarlo
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
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Wen MH, Lee KZ. Diaphragm and Intercostal Muscle Activity after Mid-Cervical Spinal Cord Contusion in the Rat. J Neurotrauma 2018; 35:533-547. [DOI: 10.1089/neu.2017.5128] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Ming-Han Wen
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, Kaohsiung, Taiwan
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36
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Huang Z, Li R, Liu J, Huang Z, Hu Y, Wu X, Zhu Q. Longitudinal electrophysiological changes after cervical hemi-contusion spinal cord injury in rats. Neurosci Lett 2017; 664:116-122. [PMID: 29138091 DOI: 10.1016/j.neulet.2017.11.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To evaluate the longitudinal somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) characterization from acute to chronic injury following cervical hemi-contusion spinal cord injury (SCI) in rats, and correlate the MEPs & SEPs to the behavioral outcomes. METHODS Fifteen adult male Sprague-Dawley rats were subjected to the hemi-contusion spinal cord injury at C5. Forelimb MEPs & SEPs were applied to 5 animals before injury and 3h, 1d, 3d, 1w, 2w, 4w and 8w after injury respectively. Forelimb functional assessments, including Montoya staircase task and cylinder rearing test, were conducted on another 10 animals before injury and at 2w, 4w and 8w after injury respectively, as well as histological analysis of the cord at 8w after injury. A group correlation was performed between the MEPs & SEPs and behavioral outcomes. RESULTS The hemi-contusion injury resulted in unilateral tissue damage at the epicenter with loss of the ventral horns and lateral funiculus. Both ipsilateral and contralateral forelimb MEPs showed latency prolongation and amplitude reduction at 3h after injury. The MEPs amplitude increased with time after injury, but the ipsilateral amplitude was persistently lower than the contralateral amplitude. The ipsilateral MEPs latency increased with time after injury and was significantly longer than the contralateral MEPs latency. The ipsilateral SEPs amplitude dropped after injury and stayed at a lower level up to 8 weeks. There was no difference in the SEPs latency among time points and between sides. At 8 weeks after injury, the ipsilateral forelimb grasped 30% pellets while the contralateral forelimb close to 81%. An obvious decreased usage of the ipsilateral paw and increased usage of the contralateral paw were observed in rearing test after injury. The MEPs latency and amplitude correlated significantly with the forelimb motor function. CONCLUSION Cervical hemi-contusion SCI led to persistent changes in MEPs & SEPs of the ipsilateral forelimb, ipsilateral impairment in motor function and unilateral cord tissue damage. Reliable electrophysiology assessment was obtained in chronic phase due to unstable MEPs & SEPs of bilateral forelimb immediately after injury, which might reflect the underlying pathological processes. The present study further confirmed the link of the MEPs to the behavioral outcomes, supporting the longitudinal electrophysiology assessment for neurological impairment after SCI.
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Affiliation(s)
- Zucheng Huang
- Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Rong Li
- Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Junhao Liu
- Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhiping Huang
- Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yong Hu
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Xiaoliang Wu
- Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Qingan Zhu
- Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.
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37
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Lee KZ, Hsu SH. Compensatory Function of the Diaphragm after High Cervical Hemisection in the Rat. J Neurotrauma 2017; 34:2634-2644. [DOI: 10.1089/neu.2016.4943] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shih-Hui Hsu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
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38
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Minic Z, Wilson S, Liu F, Sankari A, Mao G, Goshgarian H. Nanoconjugate-bound adenosine A 1 receptor antagonist enhances recovery of breathing following acute cervical spinal cord injury. Exp Neurol 2017; 292:56-62. [PMID: 28223038 DOI: 10.1016/j.expneurol.2017.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 02/09/2017] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
Abstract
Respiratory complications in patients with spinal cord injury (SCI) are common and can have a negative impact on the quality of patients' lives. Previously, we found that intradiaphragmatic administration of the nanoconjugate-bound A1 adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) induced recovery of diaphragm function following SCI in rats. When administered immediately following the injury, recovery was observed as early as 3days following SCI and it persisted until the end of the study, 28days after the drug delivery. The recovery was observed using diaphragmatic electromyography (EMG) as well as phrenic nerve recordings; both of which were conducted under anesthetized conditions. Confounding effects of anesthetic may make data interpretation complex in terms of the impact on overall ventilatory function and clinical relevance. The objective of the present study was to test the hypothesis that intradiaphragmatic administration of nanoconjugate-bound DPCPX, enhances recovery of ventilation following SCI in the unanesthetized rat. To that end, Sprague-Dawley rats underwent C2 spinal cord hemisection (C2Hx) on day 0 and received either: (i) 0.15μg/kg of nanoconjugate-bound DPCPX or (ii) vehicle control (50μl distilled water). To assess ventilation, unrestrained whole body plethysmography (WBP) was performed on day 0 (immediately before the surgery) and 3, 7, 14, 21 and 28days following the SCI. Frequency, tidal volume, and minute ventilation data were analyzed in two minute bins while the animal was calm and awake. We found that a single administration of the nanoconjugate-bound A1 adenosine receptor antagonist facilitated recovery of tidal volume and minute ventilation following SCI. Furthermore, the treatment attenuated SCI-associated increases in respiratory frequency. Taken together, this study suggests that the previously observed DPCPX nanoconjugate-induced recovery in diaphragmatic and phrenic motor outputs may translate to a clinically meaningful improvement in ventilatory function in patients with SCI.
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Affiliation(s)
- Zeljka Minic
- Wayne State University, School of Medicine, Department of Anatomy and Cell Biology, 540 E. Canfield St, Detroit, MI 48201, United States; Wayne State University, School of Medicine, Cardiovascular Research Institute, 540 E. Canfield St, Detroit, MI 48201, United States.
| | - Sharowyn Wilson
- Wayne State University, School of Medicine, Department of Anatomy and Cell Biology, 540 E. Canfield St, Detroit, MI 48201, United States
| | - Fangchao Liu
- Wayne State University, Department of Chemical Engineering and Materials Science, 5050 Anthony Wayne Drive, Detroit, MI 48202, United States
| | - Abdulghani Sankari
- Wayne State University, School of Medicine, Department of Anatomy and Cell Biology, 540 E. Canfield St, Detroit, MI 48201, United States; Wayne State University, School of Medicine, Cardiovascular Research Institute, 540 E. Canfield St, Detroit, MI 48201, United States; John D. Dingell VA Medical center, Department of Medicine, 4646 John R, Detroit, MI, 48201, United States
| | - Guangzhao Mao
- Wayne State University, Department of Chemical Engineering and Materials Science, 5050 Anthony Wayne Drive, Detroit, MI 48202, United States
| | - Harry Goshgarian
- Wayne State University, School of Medicine, Department of Anatomy and Cell Biology, 540 E. Canfield St, Detroit, MI 48201, United States
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39
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Vagal Control of Breathing Pattern after Midcervical Contusion in Rats. J Neurotrauma 2017; 34:734-745. [DOI: 10.1089/neu.2016.4645] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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40
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Squair JW, West CR, Popok D, Assinck P, Liu J, Tetzlaff W, Krassioukov AV. High Thoracic Contusion Model for the Investigation of Cardiovascular Function after Spinal Cord Injury. J Neurotrauma 2017; 34:671-684. [DOI: 10.1089/neu.2016.4518] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Jordan W. Squair
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- MD/PhD Training Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher R. West
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David Popok
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Peggy Assinck
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, Faculty of Science, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrei V. Krassioukov
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, British Columbia, Canada
- GF Strong Rehabilitation Centre, Vancouver Health Authority, Vancouver, British Columbia, Canada
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Hormigo KM, Zholudeva LV, Spruance VM, Marchenko V, Cote MP, Vinit S, Giszter S, Bezdudnaya T, Lane MA. Enhancing neural activity to drive respiratory plasticity following cervical spinal cord injury. Exp Neurol 2017; 287:276-287. [PMID: 27582085 PMCID: PMC5121051 DOI: 10.1016/j.expneurol.2016.08.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/20/2016] [Accepted: 08/26/2016] [Indexed: 02/07/2023]
Abstract
Cervical spinal cord injury (SCI) results in permanent life-altering sensorimotor deficits, among which impaired breathing is one of the most devastating and life-threatening. While clinical and experimental research has revealed that some spontaneous respiratory improvement (functional plasticity) can occur post-SCI, the extent of the recovery is limited and significant deficits persist. Thus, increasing effort is being made to develop therapies that harness and enhance this neuroplastic potential to optimize long-term recovery of breathing in injured individuals. One strategy with demonstrated therapeutic potential is the use of treatments that increase neural and muscular activity (e.g. locomotor training, neural and muscular stimulation) and promote plasticity. With a focus on respiratory function post-SCI, this review will discuss advances in the use of neural interfacing strategies and activity-based treatments, and highlights some recent results from our own research.
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Affiliation(s)
- Kristiina M Hormigo
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Lyandysha V Zholudeva
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Victoria M Spruance
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Vitaliy Marchenko
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Marie-Pascale Cote
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Stephane Vinit
- Université de Versailles Saint-Quentin-en-Yvelines, INSERM U1179 End:icap, UFR des Sciences de la Santé - Simone Veil, Montigny-le-Bretonneux, France
| | - Simon Giszter
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Tatiana Bezdudnaya
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA
| | - Michael A Lane
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, 2900 W Queen Lane, Philadelphia, PA, USA.
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42
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Lee KZ, Chiang SC, Li YJ. Mild Acute Intermittent Hypoxia Improves Respiratory Function in Unanesthetized Rats With Midcervical Contusion. Neurorehabil Neural Repair 2016; 31:364-375. [DOI: 10.1177/1545968316680494] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background. Mild intermittent hypoxia has been considered a potential approach to induce respiratory neuroplasticity. Objective. The purpose of the present study was to investigate whether mild acute intermittent hypoxia can improve breathing function in a clinically relevant spinal cord injury animal model. Methods. Adult male rats received laminectomy or unilateral contusion at the C3-C4 spinal cord using a MASCIS Impactor (height: 6.25 or 12.5 mm). At 4 weeks postinjury, the breathing patterns of unanesthetized rats were measured by whole body plethysmography before, during and after 10 episodes of 5 minutes of hypoxia (10% O2, 4% CO2, balance N2) with 5 minutes of normoxia intervals. Results. The results demonstrated that cervical contusion resulted in reduction in breathing capacity and number of phrenic motoneurons. Acute hypoxia induced significant increases in frequency and tidal volume in sham surgery and contused animals. In addition, there was a progressive decline in the magnitude of hypoxic ventilatory response during intermittent hypoxia. Further, the tidal volume was significantly enhanced in contused but not sham surgery rats at 15 and 30 minutes postintermittent hypoxia, suggesting intermittent hypoxia can bring about long-term facilitation of tidal volume following cervical spinal contusion. Conclusions. These results suggest that mild acute intermittent hypoxia can elicit differential forms of respiratory plasticity in sham surgery versus contused animals, and may be a promising neurorehabilitation approach to improve respiratory function after cervical spinal cord injury.
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Affiliation(s)
- Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shu-Chi Chiang
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Yu-Jie Li
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
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Rana S, Sieck GC, Mantilla CB. Diaphragm electromyographic activity following unilateral midcervical contusion injury in rats. J Neurophysiol 2016; 117:545-555. [PMID: 27832610 DOI: 10.1152/jn.00727.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/03/2016] [Indexed: 12/21/2022] Open
Abstract
Contusion-type injuries to the spinal cord are characterized by tissue loss and disruption of spinal pathways. Midcervical spinal cord injuries impair the function of respiratory muscles and may contribute to significant respiratory complications. This study systematically assessed the impact of a 100-kDy unilateral C4 contusion injury on diaphragm muscle activity across a range of motor behaviors in rats. Chronic diaphragm electromyography (EMG) was recorded before injury and at 1 and 7 days postinjury (DPI). Histological analyses assessed the extent of perineuronal net formation, white-matter sparing, and phrenic motoneuron loss. At 7 DPI, ∼45% of phrenic motoneurons were lost ipsilaterally. Relative diaphragm root mean square (RMS) EMG activity increased bilaterally across a range of motor behaviors by 7 DPI. The increase in diaphragm RMS EMG activity was associated with an increase in neural drive (RMS value at 75 ms after the onset of diaphragm activity) and was more pronounced during higher force, nonventilatory motor behaviors. Animals in the contusion group displayed a transient decrease in respiratory rate and an increase in burst duration at 1 DPI. By 7 days, following midcervical contusion, there was significant perineuronal net formation and white-matter loss that spanned 1 mm around the injury epicenter. Taken together, these findings are consistent with increased recruitment of remaining motor units, including more fatigable, high-threshold motor units, during higher force, nonventilatory behaviors. Changes in diaphragm EMG activity following midcervical contusion injury reflect complex adaptations in neuromotor control that may increase the risk of motor-unit fatigue and compromise the ability to sustain higher force diaphragm efforts. NEW & NOTEWORTHY The present study shows that unilateral contusion injury at C4 results in substantial loss of phrenic motoneurons but increased diaphragm muscle activity across a range of ventilatory and higher force, nonventilatory behaviors. Measures of neural drive indicate increased descending input to phrenic motoneurons that was more pronounced during higher force, nonventilatory behaviors. These findings reveal novel, complex adaptations in neuromotor control following injury, suggestive of increased recruitment of more fatigable, high-threshold motor units.
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Affiliation(s)
- Sabhya Rana
- Departments of Physiology & Biomedical Engineering and Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Departments of Physiology & Biomedical Engineering and Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | - Carlos B Mantilla
- Departments of Physiology & Biomedical Engineering and Anesthesiology, Mayo Clinic, Rochester, Minnesota
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Charsar BA, Urban MW, Lepore AC. Harnessing the power of cell transplantation to target respiratory dysfunction following spinal cord injury. Exp Neurol 2016; 287:268-275. [PMID: 27531634 DOI: 10.1016/j.expneurol.2016.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 07/29/2016] [Accepted: 08/12/2016] [Indexed: 12/13/2022]
Abstract
The therapeutic benefit of cell transplantation has been assessed in a host of central nervous system (CNS) diseases, including disorders of the spinal cord such as traumatic spinal cord injury (SCI). The promise of cell transplantation to preserve and/or restore normal function can be aimed at a variety of therapeutic mechanisms, including replacement of lost or damaged CNS cell types, promotion of axonal regeneration or sprouting, neuroprotection, immune response modulation, and delivery of gene products such as neurotrophic factors, amongst other possibilities. Despite significant work in the field of transplantation in models of SCI, limited attention has been directed at harnessing the therapeutic potential of cell grafting for preserving respiratory function after SCI, despite the critical role pulmonary compromise plays in patient outcome in this devastating disease. Here, we will review the limited number of studies that have demonstrated the therapeutic potential of intraspinal transplantation of a variety of cell types for addressing respiratory dysfunction in SCI.
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Affiliation(s)
- Brittany A Charsar
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College, Thomas Jefferson University, 900 Walnut Street, JHN 418, Philadelphia, PA, 19107, United States
| | - Mark W Urban
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College, Thomas Jefferson University, 900 Walnut Street, JHN 418, Philadelphia, PA, 19107, United States
| | - Angelo C Lepore
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College, Thomas Jefferson University, 900 Walnut Street, JHN 418, Philadelphia, PA, 19107, United States.
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Garara B, Wood A, Marcus HJ, Tsang K, Wilson MH, Khan M. Intramuscular diaphragmatic stimulation for patients with traumatic high cervical injuries and ventilator dependent respiratory failure: A systematic review of safety and effectiveness. Injury 2016; 47:539-44. [PMID: 26803697 DOI: 10.1016/j.injury.2015.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/23/2015] [Accepted: 12/26/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND Intramuscular diaphragmatic stimulation using an abdominal laparoscopic approach has been proposed as a safer alternative to traditional phrenic nerve stimulation. It has also been suggested that early implementation of diaphragmatic pacing may prevent diaphragm atrophy and lead to earlier ventilator independence. The aim of this study was therefore to systematically review the safety and effectiveness of intramuscular diaphragmatic stimulators in the treatment of patients with traumatic high cervical injuries resulting in long-term ventilator dependence, with particular emphasis on the affect of timing of insertion of such stimulators. METHODS The Cochrane database and PubMed were searched between January 2000 and June 2015. Reference lists of selected papers were also reviewed. The inclusion criteria used to select from the pool of eligible studies were: (1) reported on adult patients with traumatic high cervical injury, who were ventilator-dependant, (2) patients underwent intramuscular diaphragmatic stimulation, and (3) commented on safety and/or effectiveness. RESULTS 12 articles were included in the review. Reported safety issues post insertion of intramuscular electrodes included pneumothorax, infection, and interaction with pre-existing cardiac pacemaker. Only one procedural failure was reported. The percentage of patients reported as independent of ventilatory support post procedure ranged between 40% and 72.2%. The mean delay of insertion ranged from 40 days to 9.7 years; of note the study with the average shortest delay in insertion reported the greatest percentage of fully weaned patients. CONCLUSIONS Although evidence for intramuscular diaphragmatic stimulation in patients with high cervical injuries and ventilator dependent respiratory failure is currently limited, the technique appears to be safe and effective. Earlier implantation of such devices does not appear to be associated with greater surgical risk, and may be more effective. Further high quality studies are warranted to investigate the impact of delay of insertion on ventilator weaning.
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Affiliation(s)
- Bhavin Garara
- Department of General Surgery, Imperial College Healthcare NHS Trust, London, UK
| | - Alasdair Wood
- Department of General Surgery, Imperial College Healthcare NHS Trust, London, UK
| | - Hani J Marcus
- Department of Neurosurgery, Imperial College Healthcare NHS Trust, London, UK
| | - Kevin Tsang
- Department of Neurosurgery, Imperial College Healthcare NHS Trust, London, UK
| | - Mark H Wilson
- Department of Neurosurgery, Imperial College Healthcare NHS Trust, London, UK
| | - Mansoor Khan
- Department of General Surgery, Imperial College Healthcare NHS Trust, London, UK.
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Alvarez-Argote S, Gransee HM, Mora JC, Stowe JM, Jorgenson AJ, Sieck GC, Mantilla CB. The Impact of Midcervical Contusion Injury on Diaphragm Muscle Function. J Neurotrauma 2015; 33:500-9. [PMID: 26413840 DOI: 10.1089/neu.2015.4054] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Midcervical contusion injuries disrupt descending ipsilateral excitatory bulbospinal projections to phrenic motoneurons, compromising ventilation. We hypothesized that a unilateral contusion injury at C3 versus C5 would differentially impact phrenic activity reflecting more prominent disruption of ipsilateral descending excitatory drive to more caudal segments of the phrenic motor pool with more cranial injuries. Phrenic motoneuron counts and evidence of diaphragm muscle denervation at individual neuromuscular junctions (NMJ) were evaluated at 14 days post-injury after unilateral contusion injury (100 kDynes). Whole body plethysmography and chronic diaphragm EMG were measured before the injury and at 3, 7, and 14 days post-injury. Contusion injuries at either level resulted in a similarly sized cavity. C3 contusion resulted in loss of 39 ± 13% of ipsilateral phrenic motoneurons compared with 13 ± 21% after C5 contusion (p = 0.003). Cervical contusion injuries resulted in diaphragm muscle denervation (C3 contusion: 17 ± 4%; C5 contusion: 7 ± 4%; p = 0.047). The pattern of denervation revealed segmental innervation of the diaphragm muscle, with greater denervation ventrally after C3 contusion and dorsally after C5 contusion. Overall, diaphragm root mean square electromyography activity did not change ipsilaterally after C3 or C5 contusion, but increased contralaterally (∼ 11%) after C3 contusion only on the first day post-injury (p = 0.026). Similarly, there were no significant changes in breathing parameters during eupnea or exposure to hypoxia (10% O2) - hypercapnia (5% CO2) at any time post-injury. Unilateral midcervical contusions minimally impair ventilatory behaviors despite phrenic motoneuron loss and diaphragm muscle denervation.
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Affiliation(s)
| | - Heather M Gransee
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Juan C Mora
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Jessica M Stowe
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Amy J Jorgenson
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Gary C Sieck
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,2 Department of Anesthesiology, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,2 Department of Anesthesiology, Mayo Clinic , Rochester, Minnesota
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47
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Meyer MR, Haeusler M. Spinal cord evolution in early Homo. J Hum Evol 2015; 88:43-53. [DOI: 10.1016/j.jhevol.2015.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 10/22/2022]
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Gill LC, Gransee HM, Sieck GC, Mantilla CB. Functional recovery after cervical spinal cord injury: Role of neurotrophin and glutamatergic signaling in phrenic motoneurons. Respir Physiol Neurobiol 2015; 226:128-36. [PMID: 26506253 DOI: 10.1016/j.resp.2015.10.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/15/2015] [Accepted: 10/17/2015] [Indexed: 11/19/2022]
Abstract
Cervical spinal cord injury (SCI) interrupts descending neural drive to phrenic motoneurons causing diaphragm muscle (DIAm) paralysis. Recent studies using a well-established model of SCI, unilateral spinal hemisection of the C2 segment of the cervical spinal cord (SH), provide novel information regarding the molecular and cellular mechanisms of functional recovery after SCI. Over time post-SH, gradual recovery of rhythmic ipsilateral DIAm activity occurs. Recovery of ipsilateral DIAm electromyogram (EMG) activity following SH is enhanced by increasing brain-derived neurotrophic factor (BDNF) in the region of the phrenic motoneuron pool. Delivery of exogenous BDNF either via intrathecal infusion or via mesenchymal stem cells engineered to release BDNF similarly enhance recovery. Conversely, recovery after SH is blunted by quenching endogenous BDNF with the fusion-protein TrkB-Fc in the region of the phrenic motoneuron pool or by selective inhibition of TrkB kinase activity using a chemical-genetic approach in TrkB(F616A) mice. Furthermore, the importance of BDNF signaling via TrkB receptors at phrenic motoneurons is highlighted by the blunting of recovery by siRNA-mediated downregulation of TrkB receptor expression in phrenic motoneurons and by the enhancement of recovery evident following virally-induced increases in TrkB expression specifically in phrenic motoneurons. BDNF/TrkB signaling regulates synaptic plasticity in various neuronal systems, including glutamatergic pathways. Glutamatergic neurotransmission constitutes the main inspiratory-related, excitatory drive to motoneurons, and following SH, spontaneous neuroplasticity is associated with increased expression of ionotropic N-methyl-d-aspartate (NMDA) receptors in phrenic motoneurons. Evidence for the role of BDNF/TrkB and glutamatergic signaling in recovery of DIAm activity following cervical SCI is reviewed.
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Affiliation(s)
- Luther C Gill
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55906, United States
| | - Heather M Gransee
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55906, United States
| | - Gary C Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55906, United States; Department of Anesthesiology, Mayo Clinic, Rochester, MN 55906, United States
| | - Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55906, United States; Department of Anesthesiology, Mayo Clinic, Rochester, MN 55906, United States.
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49
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Terson de Paleville D, Lorenz D. Compensatory muscle activation during forced respiratory tasks in individuals with chronic spinal cord injury. Respir Physiol Neurobiol 2015; 217:54-62. [DOI: 10.1016/j.resp.2015.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 10/23/2022]
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50
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Li K, Javed E, Scura D, Hala TJ, Seetharam S, Falnikar A, Richard JP, Chorath A, Maragakis NJ, Wright MC, Lepore AC. Human iPS cell-derived astrocyte transplants preserve respiratory function after spinal cord injury. Exp Neurol 2015. [PMID: 26216662 DOI: 10.1016/j.expneurol.2015.07.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Transplantation-based replacement of lost and/or dysfunctional astrocytes is a promising therapy for spinal cord injury (SCI) that has not been extensively explored, despite the integral roles played by astrocytes in the central nervous system (CNS). Induced pluripotent stem (iPS) cells are a clinically-relevant source of pluripotent cells that both avoid ethical issues of embryonic stem cells and allow for homogeneous derivation of mature cell types in large quantities, potentially in an autologous fashion. Despite their promise, the iPS cell field is in its infancy with respect to evaluating in vivo graft integration and therapeutic efficacy in SCI models. Astrocytes express the major glutamate transporter, GLT1, which is responsible for the vast majority of glutamate uptake in spinal cord. Following SCI, compromised GLT1 expression/function can increase susceptibility to excitotoxicity. We therefore evaluated intraspinal transplantation of human iPS cell-derived astrocytes (hIPSAs) following cervical contusion SCI as a novel strategy for reconstituting GLT1 expression and for protecting diaphragmatic respiratory neural circuitry. Transplant-derived cells showed robust long-term survival post-injection and efficiently differentiated into astrocytes in injured spinal cord of both immunesuppressed mice and rats. However, the majority of transplant-derived astrocytes did not express high levels of GLT1, particularly at early times post-injection. To enhance their ability to modulate extracellular glutamate levels, we engineered hIPSAs with lentivirus to constitutively express GLT1. Overexpression significantly increased GLT1 protein and functional GLT1-mediated glutamate uptake levels in hIPSAs both in vitro and in vivo post-transplantation. Compared to human fibroblast control and unmodified hIPSA transplantation, GLT1-overexpressing hIPSAs reduced (1) lesion size within the injured cervical spinal cord, (2) morphological denervation by respiratory phrenic motor neurons at the diaphragm neuromuscular junction, and (3) functional diaphragm denervation as measured by recording of spontaneous EMGs and evoked compound muscle action potentials. Our findings demonstrate that hiPSA transplantation is a therapeutically-powerful approach for SCI.
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Affiliation(s)
- Ke Li
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Elham Javed
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Daniel Scura
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Tamara J Hala
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Suneil Seetharam
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Aditi Falnikar
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Jean-Philippe Richard
- Department of Neurology, Johns Hopkins University School of Medicine, 855N. Wolfe St., Rangos 250, Baltimore, MD 21205, United States.
| | - Ashley Chorath
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Nicholas J Maragakis
- Department of Neurology, Johns Hopkins University School of Medicine, 855N. Wolfe St., Rangos 250, Baltimore, MD 21205, United States.
| | - Megan C Wright
- Department of Biology, Arcadia University, 450S. Easton Rd., 220 Boyer Hall, Glenside, PA 19038, United States.
| | - Angelo C Lepore
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
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