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Moritz C, Field-Fote EC, Tefertiller C, van Nes I, Trumbower R, Kalsi-Ryan S, Purcell M, Janssen TWJ, Krassioukov A, Morse LR, Zhao KD, Guest J, Marino RJ, Murray LM, Wecht JM, Rieger M, Pradarelli J, Turner A, D'Amico J, Squair JW, Courtine G. Non-invasive spinal cord electrical stimulation for arm and hand function in chronic tetraplegia: a safety and efficacy trial. Nat Med 2024; 30:1276-1283. [PMID: 38769431 PMCID: PMC11108781 DOI: 10.1038/s41591-024-02940-9] [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: 12/01/2023] [Accepted: 03/22/2024] [Indexed: 05/22/2024]
Abstract
Cervical spinal cord injury (SCI) leads to permanent impairment of arm and hand functions. Here we conducted a prospective, single-arm, multicenter, open-label, non-significant risk trial that evaluated the safety and efficacy of ARCEX Therapy to improve arm and hand functions in people with chronic SCI. ARCEX Therapy involves the delivery of externally applied electrical stimulation over the cervical spinal cord during structured rehabilitation. The primary endpoints were safety and efficacy as measured by whether the majority of participants exhibited significant improvement in both strength and functional performance in response to ARCEX Therapy compared to the end of an equivalent period of rehabilitation alone. Sixty participants completed the protocol. No serious adverse events related to ARCEX Therapy were reported, and the primary effectiveness endpoint was met. Seventy-two percent of participants demonstrated improvements greater than the minimally important difference criteria for both strength and functional domains. Secondary endpoint analysis revealed significant improvements in fingertip pinch force, hand prehension and strength, upper extremity motor and sensory abilities and self-reported increases in quality of life. These results demonstrate the safety and efficacy of ARCEX Therapy to improve hand and arm functions in people living with cervical SCI. ClinicalTrials.gov identifier: NCT04697472 .
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Affiliation(s)
- Chet Moritz
- Departments of Rehabilitation Medicine, Electrical & Computer Engineering, Physiology & Biophysics and Center for Neurotechnology, University of Washington, Seattle, WA, USA
| | - Edelle C Field-Fote
- Shepherd Center, Crawford Research Institute and Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Ilse van Nes
- Sint Maartenskliniek, Revalidatiegeneeskunde, Nijmegen, The Netherlands
| | - Randy Trumbower
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA
- Spaulding Rehabilitation Hospital, Charlestown, MA, USA
| | - Sukhvinder Kalsi-Ryan
- KITE Research Institute|Toronto Rehab, University Health Network, Toronto, Ontario, Canada
| | - Mariel Purcell
- Scottish Centre for Innovation in Spinal Cord Injury, Queen Elizabeth National Spinal Injuries Unit, Queen Elizabeth University Hospital, Glasgow, UK
| | - Thomas W J Janssen
- Amsterdam Rehabilitation Research Center | Reade, Amsterdam, The Netherlands
- Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Andrei Krassioukov
- ICORD and Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, British Columbia, Canada
| | - Leslie R Morse
- Department of Rehabilitation Medicine, University of Minnesota School of Medicine, Minneapolis, MN, USA
| | - Kristin D Zhao
- Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, MN, USA
| | - James Guest
- Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
- Miami Project to Cure Paralysis, Miami, FL, USA
| | - Ralph J Marino
- Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Lynda M Murray
- Departments of Rehabilitation and Human Performance and Medicine, James J. Peters VA Medical Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Research and Development, James J. Peters VA Medical Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jill M Wecht
- Department of Research and Development, James J. Peters VA Medical Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | | | - Jessica D'Amico
- ONWARD Medical, Lausanne, Switzerland
- Glenrose Rehabilitation Hospital, Alberta Health Services, Edmonton, Alberta, Canada
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Jordan W Squair
- NeuroX Institute and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland
- Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
- Defitech Center for Interventional Neurotherapies (NeuroRestore), EPFL/CHUV/UNIL, Lausanne, Switzerland
- NeuroRestore, NeuroX Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Gregoire Courtine
- NeuroX Institute and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland.
- Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
- Defitech Center for Interventional Neurotherapies (NeuroRestore), EPFL/CHUV/UNIL, Lausanne, Switzerland.
- NeuroRestore, NeuroX Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
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Li E, Yan R, Qiao H, Sun J, Zou P, Chang J, Li S, Ma Q, Zhang R, Liao B. Combined transcriptomics and proteomics studies on the effect of electrical stimulation on spinal cord injury in rats. Heliyon 2024; 10:e23960. [PMID: 38226269 PMCID: PMC10788535 DOI: 10.1016/j.heliyon.2023.e23960] [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: 03/02/2023] [Revised: 11/20/2023] [Accepted: 12/19/2023] [Indexed: 01/17/2024] Open
Abstract
Electrical stimulation (ES) of the spinal cord is a promising therapy for functional rehabilitation after spinal cord injury (SCI). However, the specific mechanism of action is poorly understood. We designed and applied an implanted ES device in the SCI area in rats and determined the effect of ES on the treatment of motor dysfunction after SCI using behavioral scores. Additionally, we examined the molecular characteristics of the samples using proteomic and transcriptomic sequencing. The differential molecules between groups were identified using statistical analyses. Molecular, network, and pathway-based analyses were used to identify group-specific biological features. ES (0.5 mA, 0.1 ms, 50 Hz) had a positive effect on motor dysfunction and neuronal regeneration in rats after SCI. Six samples (three independent replicates in each group) were used for transcriptome sequencing; we obtained 1026 differential genes, comprising 274 upregulated genes and 752 downregulated genes. A total of 10 samples were obtained: four samples in the ES group and six samples in the SCI group; for the proteome sequencing, 48 differential proteins were identified, including 45 up-regulated and three down-regulated proteins. Combined transcriptomic and proteomic studies have shown that the main enrichment pathway is the hedgehog signaling pathway. Western blot results showed that the expression levels of Sonic hedgehog (SHH) (P < 0.001), Smoothened (SMO) (P = 0.0338), and GLI-1 (P < 0.01) proteins in the ES treatment group were significantly higher than those in the SCI group. The immunofluorescence results showed significantly increased expression of SHH (P = 0.0181), SMO (P = 0.021), and GLI-1 (P = 0.0126) in the ES group compared with that in the SCI group. In conclusion, ES after SCI had a positive effect on motor dysfunction and anti-inflammatory effects in rats. Moreover, transcriptomic and proteomic sequencing also provided unique perspectives on the complex relationships between ES on SCI, where the SHH signaling pathway plays a critical role. Our study provides a significant theoretical foundation for the clinical implementation of ES therapy in patients with SCI.
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Affiliation(s)
- Erliang Li
- Department of Joint Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Rongbao Yan
- Department of Orthopaedics, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Huanhuan Qiao
- Department of Orthopaedics, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an, Shaanxi, China
| | - Jin Sun
- Department of Orthopaedics, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an, Shaanxi, China
| | - Peng Zou
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jiaqi Chang
- School of Automation Science and Electrical Engineering, Beihang University, 37th Xueyuan Road, Beijing, China
| | - Shuang Li
- Department of Orthopaedics, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an, Shaanxi, China
| | - Qiong Ma
- Department of Orthopaedics, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an, Shaanxi, China
| | - Rui Zhang
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Bo Liao
- Department of Orthopaedics, The Second Affiliated Hospital of Air Force Military Medical University, Xi'an, Shaanxi, China
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Lavekar SS, Patel MD, Montalvo-Parra MD, Krencik R. Asteroid impact: the potential of astrocytes to modulate human neural networks within organoids. Front Neurosci 2023; 17:1305921. [PMID: 38075269 PMCID: PMC10702564 DOI: 10.3389/fnins.2023.1305921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/08/2023] [Indexed: 02/12/2024] Open
Abstract
Astrocytes are a vital cellular component of the central nervous system that impact neuronal function in both healthy and pathological states. This includes intercellular signals to neurons and non-neuronal cells during development, maturation, and aging that can modulate neural network formation, plasticity, and maintenance. Recently, human pluripotent stem cell-derived neural aggregate cultures, known as neurospheres or organoids, have emerged as improved experimental platforms for basic and pre-clinical neuroscience compared to traditional approaches. Here, we summarize the potential capability of using organoids to further understand the mechanistic role of astrocytes upon neural networks, including the production of extracellular matrix components and reactive signaling cues. Additionally, we discuss the application of organoid models to investigate the astrocyte-dependent aspects of neuropathological diseases and to test astrocyte-inspired technologies. We examine the shortcomings of organoid-based experimental platforms and plausible improvements made possible by cutting-edge neuroengineering technologies. These advancements are expected to enable the development of improved diagnostic strategies and high-throughput translational applications regarding neuroregeneration.
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Affiliation(s)
| | | | | | - R. Krencik
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
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Chung YC, Shemmell J, Kumala C, Soedirdjo SDH, Dhaher YY. Identifying spinal tracts transmitting distant effects of trans-spinal magnetic stimulation. J Neurophysiol 2023; 130:883-894. [PMID: 37646076 DOI: 10.1152/jn.00202.2023] [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: 05/17/2023] [Revised: 08/14/2023] [Accepted: 08/25/2023] [Indexed: 09/01/2023] Open
Abstract
Estimating the state of tract-specific inputs to spinal motoneurons is critical to understanding movement deficits induced by neurological injury and potential pathways to recovery but remains challenging in humans. In this study, we explored the capability of trans-spinal magnetic stimulation (TSMS) to modulate distal reflex circuits in young adults. TSMS was applied over the thoracic spine to condition soleus H-reflexes involving sacral-level motoneurons. Three TSMS intensities below the motor threshold were applied at interstimulus intervals (ISIs) between 2 and 20 ms relative to peripheral nerve stimulation (PNS). Although low-intensity TSMS yielded no changes in H-reflexes across ISIs, the two higher stimulus intensities yielded two phases of H-reflex inhibition: a relatively long-lasting period at 2- to 9-ms ISIs, and a short phase at 11- to 12-ms ISIs. H-reflex inhibition at 2-ms ISI was uniquely dependent on TSMS intensity. To identify the candidate neural pathways contributing to H-reflex suppression, we constructed a tract-specific conduction time estimation model. Based upon our model, H-reflex inhibition at 11- to 12-ms ISIs is likely a manifestation of orthodromic transmission along the lateral reticulospinal tract. In contrast, the inhibition at 2-ms ISI likely reflects orthodromic transmission along sensory fibers with activation reaching the brain, before descending along motor tracts. Multiple pathways may contribute to H-reflex modulation between 4- and 9-ms ISIs, orthodromic transmission along sensorimotor tracts, and antidromic transmission of multiple motor tracts. Our findings suggest that noninvasive TSMS can influence motoneuron excitability at distal segments and that the contribution of specific tracts to motoneuron excitability may be distinguishable based on conduction velocities.NEW & NOTEWORTHY This study explored the capability of trans-spinal magnetic stimulation (TSMS) over the thoracic spine to modulate distal reflex circuits, H-reflexes involving sacral-level motoneurons, in young adults. TSMS induced two inhibition phases of H-reflex across interstimulus intervals (ISIs): a relatively long-lasting period at 2- to 9-ms ISIs, and a short phase at 11- to 12-ms ISIs. An estimated probability model constructed from tract-specific conduction velocities allowed the identification of potential spinal tracts contributing to the changes in motoneuron excitability.
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Affiliation(s)
- Yu-Chen Chung
- Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Jonathan Shemmell
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, Australia
| | - Caitlin Kumala
- Department of Biology, University of Texas at Dallas, Richardson, Texas, United States
| | - Subaryani D H Soedirdjo
- Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Yasin Y Dhaher
- Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, United States
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas, United States
- Peter O'Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, Texas, United States
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Mondello SE, Young L, Dang V, Fischedick AE, Tolley NM, Wang T, Bravo MA, Lee D, Tucker B, Knoernschild M, Pedigo BD, Horner PJ, Moritz CT. Optogenetic spinal stimulation promotes new axonal growth and skilled forelimb recovery in rats with sub-chronic cervical spinal cord injury. J Neural Eng 2023; 20:056005. [PMID: 37524080 PMCID: PMC10496592 DOI: 10.1088/1741-2552/acec13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 07/17/2023] [Accepted: 07/31/2023] [Indexed: 08/02/2023]
Abstract
Objective.Spinal cord injury (SCI) leads to debilitating sensorimotor deficits that greatly limit quality of life. This work aims to develop a mechanistic understanding of how to best promote functional recovery following SCI. Electrical spinal stimulation is one promising approach that is effective in both animal models and humans with SCI. Optogenetic stimulation is an alternative method of stimulating the spinal cord that allows for cell-type-specific stimulation. The present work investigates the effects of preferentially stimulating neurons within the spinal cord and not glial cells, termed 'neuron-specific' optogenetic spinal stimulation. We examined forelimb recovery, axonal growth, and vasculature after optogenetic or sham stimulation in rats with cervical SCI.Approach.Adult female rats received a moderate cervical hemicontusion followed by the injection of a neuron-specific optogenetic viral vector ipsilateral and caudal to the lesion site. Animals then began rehabilitation on the skilled forelimb reaching task. At four weeks post-injury, rats received a micro-light emitting diode (µLED) implant to optogenetically stimulate the caudal spinal cord. Stimulation began at six weeks post-injury and occurred in conjunction with activities to promote use of the forelimbs. Following six weeks of stimulation, rats were perfused, and tissue stained for GAP-43, laminin, Nissl bodies and myelin. Location of viral transduction and transduced cell types were also assessed.Main Results.Our results demonstrate that neuron-specific optogenetic spinal stimulation significantly enhances recovery of skilled forelimb reaching. We also found significantly more GAP-43 and laminin labeling in the optogenetically stimulated groups indicating stimulation promotes axonal growth and angiogenesis.Significance.These findings indicate that optogenetic stimulation is a robust neuromodulator that could enable future therapies and investigations into the role of specific cell types, pathways, and neuronal populations in supporting recovery after SCI.
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Affiliation(s)
- Sarah E Mondello
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
- Center for Neurotechnology, Seattle, WA 98195, United States of America
| | - Lisa Young
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Viet Dang
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Amanda E Fischedick
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Nicholas M Tolley
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
- Center for Neurotechnology, Seattle, WA 98195, United States of America
| | - Tian Wang
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Madison A Bravo
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
- Center for Neurotechnology, Seattle, WA 98195, United States of America
| | - Dalton Lee
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Belinda Tucker
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Megan Knoernschild
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
| | - Benjamin D Pedigo
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
- Center for Neurotechnology, Seattle, WA 98195, United States of America
| | - Philip J Horner
- Center for Neuroregeneration, Department of Neurological Surgery, Houston Methodist Research Institute, Houston, TX 77030, United States of America
| | - Chet T Moritz
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, United States of America
- Center for Neurotechnology, Seattle, WA 98195, United States of America
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA 98195, United States of America
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, United States of America
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D’hondt N, Marcial KM, Mittal N, Costanzi M, Hoydonckx Y, Kumar P, Englesakis MF, Burns A, Bhatia A. A Scoping Review of Epidural Spinal Cord Stimulation for Improving Motor and Voiding Function Following Spinal Cord Injury. Top Spinal Cord Inj Rehabil 2023; 29:12-30. [PMID: 37235192 PMCID: PMC10208259 DOI: 10.46292/sci22-00061] [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] [Indexed: 05/28/2023]
Abstract
Objectives To identify and synthesize the existing evidence on the effectiveness and safety of epidural spinal cord stimulation (SCS) for improving motor and voiding function and reducing spasticity following spinal cord injury (SCI). Methods This scoping review was performed according to the framework of Arksey and O'Malley. Comprehensive serial searches in multiple databases (MEDLINE, Embase, Cochrane Central, Cochrane Database of Systematic Reviews, LILACS, PubMed, Web of Science, and Scopus) were performed to identify relevant publications that focused on epidural SCS for improving motor function, including spasticity, and voiding deficits in individuals with SCI. Results Data from 13 case series including 88 individuals with complete or incomplete SCI (American Spinal Injury Association Impairment Scale [AIS] grade A to D) were included. In 12 studies of individuals with SCI, the majority (83 out of 88) demonstrated a variable degree of improvement in volitional motor function with epidural SCS. Two studies, incorporating 27 participants, demonstrated a significant reduction in spasticity with SCS. Two small studies consisting of five and two participants, respectively, demonstrated improved supraspinal control of volitional micturition with SCS. Conclusion Epidural SCS can enhance central pattern generator activity and lower motor neuron excitability in individuals with SCI. The observed effects of epidural SCS following SCI suggest that the preservation of supraspinal transmission is sufficient for the recovery of volitional motor and voiding function, even in patients with complete SCI. Further research is warranted to evaluate and optimize the parameters for epidural SCS and their impact on individuals with differing degrees of severity of SCI.
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Affiliation(s)
- Nina D’hondt
- Department of Pain Medicine, Multidisciplinary Pain Center, VITAZ, Sint-Niklaas, Belgium
| | - Karmi Margaret Marcial
- Department of Anesthesiology, Philippine General Hospital, University of Philippines, Philippines
| | - Nimish Mittal
- Department of Physical Medicine and Rehabilitation, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Matteo Costanzi
- Department of Anesthesiology and Intensive Care Medicine, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Yasmine Hoydonckx
- Department of Anesthesiology and Pain Medicine, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Pranab Kumar
- Department of Anesthesiology and Pain Medicine, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Marina F. Englesakis
- MLIS Library & Information Services, University Health Network, Toronto, Ontario, Canada
| | - Anthony Burns
- Department of Physical Medicine and Rehabilitation, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Anuj Bhatia
- Department of Anesthesiology and Pain Medicine, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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Luz A, Rupp R, Ahmadi R, Weidner N. Beyond treatment of chronic pain: a scoping review about epidural electrical spinal cord stimulation to restore sensorimotor and autonomic function after spinal cord injury. Neurol Res Pract 2023; 5:14. [PMID: 37055819 PMCID: PMC10103526 DOI: 10.1186/s42466-023-00241-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/30/2023] [Indexed: 04/15/2023] Open
Abstract
Epidural electrical epinal cord stimulation (ESCS) is an established therapeutic option in various chronic pain conditions. In the last decade, proof-of-concept studies have demonstrated that ESCS in combination with task-oriented rehabilitative interventions can partially restore motor function and neurological recovery after spinal cord injury (SCI). In addition to the ESCS applications for improvement of upper and lower extremity function, ESCS has been investigated for treatment of autonomic dysfunction after SCI such as orthostatic hypotension. The aim of this overview is to present the background of ESCS, emerging concepts and its readiness to become a routine therapy in SCI beyond treatment of chronic pain conditions.
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Affiliation(s)
- Antonia Luz
- Spinal Cord Injury Center, Heidelberg University Hospital, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany
| | - Rüdiger Rupp
- Spinal Cord Injury Center, Heidelberg University Hospital, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany
| | - Rezvan Ahmadi
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Norbert Weidner
- Spinal Cord Injury Center, Heidelberg University Hospital, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
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Preservation of functional descending input to paralyzed upper extremity muscles in motor complete cervical spinal cord injury. Clin Neurophysiol 2023; 150:56-68. [PMID: 37004296 DOI: 10.1016/j.clinph.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/13/2023] [Accepted: 03/01/2023] [Indexed: 03/18/2023]
Abstract
OBJECTIVE Spinal cord injury (SCI) is classified as complete or incomplete depending on the extent of sensorimotor preservation below the injury level. However, individuals with complete SCIs can voluntarily activate paralyzed lower limb muscles alone or by engaging non-paralyzed muscles during neurophysiological assessments, indicating presence of residual pathways across the injury. However, similar phenomena have not been explored for the upper extremity (UE) muscles following cervical SCIs. METHODS Eighteen individuals with motor complete cervical SCI (AIS A or B) and five age-matched non-injured (NI) individuals performed various UE events against manual resistance during functional neurophysiological assessment (FNPA), and electromyographic (EMG) activity was recorded from UE muscles. RESULTS Our findings demonstrated i) voluntary activation of clinically paralyzed muscles as evident from EMG readouts, ii) increased activity in these muscles during events engaging muscles above the injury level, iii) reduced spectral properties of paralyzed muscles in SCI compared to NI participants. CONCLUSIONS Functional EMG activity in clinically paralyzed muscles indicate presence of residual pathways across the injury establishing supralesional control over the sublesional neural circuitry. SIGNIFICANCE The findings may help explain the neurophysiological basis for UE recovery and can be exploited in designing rehabilitation techniques to facilitate UE recovery following cervical SCIs.
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Ahmed RU, Knibbe CA, Wilkins F, Sherwood LC, Howland DR, Boakye M. Porcine spinal cord injury model for translational research across multiple functional systems. Exp Neurol 2023; 359:114267. [PMID: 36356636 DOI: 10.1016/j.expneurol.2022.114267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022]
Abstract
Animal models are necessary to identify pathological changes and help assess therapeutic outcomes following spinal cord injury (SCI). Small animal models offer value in research in terms of their easily managed size, minimal maintenance requirements, lower cost, well-characterized genomes, and ability to power research studies. However, despite these benefits, small animal models have neurologic and anatomical differences that may influence translation of results to humans and thus limiting the success of their use in preclinical studies as a direct pipeline to clinical studies. Large animal models, offer an attractive intermediary translation model that may be more successful in translating to the clinic for SCI research. This is largely due to their greater neurologic and anatomical similarities to humans. The physical characteristics of pig spinal cord, gut microbiome, metabolism, proportions of white to grey matter, bowel anatomy and function, and urinary system are strikingly similar and provide great insight into human SCI conditions. In this review, we address the variety of existing porcine injury models and their translational relevance, benefits, and drawbacks in modeling human systems and functions for neurophysiology, cardiovascular, gastrointestinal and urodynamic functions.
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Affiliation(s)
- Rakib Uddin Ahmed
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA.
| | - Chase A Knibbe
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Felicia Wilkins
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Leslie C Sherwood
- Comparative Medicine Research Unit, University of Louisville, Louisville, KY, USA
| | - Dena R Howland
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA; Robley Rex VA Medical Center, Louisville, KY 40202, USA
| | - Maxwell Boakye
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
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Insausti-Delgado A, López-Larraz E, Nishimura Y, Ziemann U, Ramos-Murguialday A. Non-invasive brain-spine interface: Continuous control of trans-spinal magnetic stimulation using EEG. Front Bioeng Biotechnol 2022; 10:975037. [PMID: 36394044 PMCID: PMC9659618 DOI: 10.3389/fbioe.2022.975037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/23/2022] [Indexed: 08/22/2023] Open
Abstract
Brain-controlled neuromodulation has emerged as a promising tool to promote functional recovery in patients with motor disorders. Brain-machine interfaces exploit this neuromodulatory strategy and could be used for restoring voluntary control of lower limbs. In this work, we propose a non-invasive brain-spine interface (BSI) that processes electroencephalographic (EEG) activity to volitionally control trans-spinal magnetic stimulation (ts-MS), as an approach for lower-limb neurorehabilitation. This novel platform allows to contingently connect motor cortical activation during leg motor imagery with the activation of leg muscles via ts-MS. We tested this closed-loop system in 10 healthy participants using different stimulation conditions. This BSI efficiently removed stimulation artifacts from EEG regardless of ts-MS intensity used, allowing continuous monitoring of cortical activity and real-time closed-loop control of ts-MS. Our BSI induced afferent and efferent evoked responses, being this activation ts-MS intensity-dependent. We demonstrated the feasibility, safety and usability of this non-invasive BSI. The presented system represents a novel non-invasive means of brain-controlled neuromodulation and opens the door towards its integration as a therapeutic tool for lower-limb rehabilitation.
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Affiliation(s)
- Ainhoa Insausti-Delgado
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- International Max Planck Research School (IMPRS) for Cognitive and Systems Neuroscience, Tübingen, Germany
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- TECNALIA, Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain
| | - Eduardo López-Larraz
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Bitbrain, Zaragoza, Spain
| | - Yukio Nishimura
- Neural Prosthetics Project, Department of Brain and Neuroscience, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ander Ramos-Murguialday
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- TECNALIA, Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain
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11
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Kolos EA, Korzhevskii DE. Age-Related Changes in Microglia of the Rat Spinal Cord. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022040172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Adapting Human-Based Transcutaneous Spinal Cord Stimulation to Develop a Clinically Relevant Animal Model. J Clin Med 2022; 11:jcm11072023. [PMID: 35407636 PMCID: PMC8999945 DOI: 10.3390/jcm11072023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 02/01/2023] Open
Abstract
Transcutaneous spinal cord stimulation (tSCS) as a neuromodulatory strategy has received great attention as a method to promote functional recovery after spinal cord injury (SCI). However, due to the noninvasive nature of tSCS, investigations have primarily focused on human applications. This leaves a critical need for the development of a suitable animal model to further our understanding of this therapeutic intervention in terms of functional and neuroanatomical plasticity and to optimize stimulation protocols. The objective of this study is to establish a new animal model of thoracolumbar tSCS that (1) can accurately recapitulate studies in healthy humans and (2) can receive a repeated and stable tSCS treatment after SCI with minimal restraint, while the electrode remains consistently positioned. We show that our model displays bilateral evoked potentials in multisegmental leg muscles characteristically comparable to humans. Our data also suggest that tSCS mainly activates dorsal root structures like in humans, thereby accounting for the different electrode-to-body-size ratio between the two species. Finally, a repeated tSCS treatment protocol in the awake rat after a complete spinal cord transection is feasible, tolerable, and safe, even with minimal body restraint. Additionally, repeated tSCS was capable of modulating motor output after SCI, providing an avenue to further investigate stimulation-based neuroplasticity and optimize treatment.
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13
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Bierman-Duquette RD, Safarians G, Huang J, Rajput B, Chen JY, Wang ZZ, Seidlits SK. Engineering Tissues of the Central Nervous System: Interfacing Conductive Biomaterials with Neural Stem/Progenitor Cells. Adv Healthc Mater 2022; 11:e2101577. [PMID: 34808031 PMCID: PMC8986557 DOI: 10.1002/adhm.202101577] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/31/2021] [Indexed: 12/19/2022]
Abstract
Conductive biomaterials provide an important control for engineering neural tissues, where electrical stimulation can potentially direct neural stem/progenitor cell (NS/PC) maturation into functional neuronal networks. It is anticipated that stem cell-based therapies to repair damaged central nervous system (CNS) tissues and ex vivo, "tissue chip" models of the CNS and its pathologies will each benefit from the development of biocompatible, biodegradable, and conductive biomaterials. Here, technological advances in conductive biomaterials are reviewed over the past two decades that may facilitate the development of engineered tissues with integrated physiological and electrical functionalities. First, one briefly introduces NS/PCs of the CNS. Then, the significance of incorporating microenvironmental cues, to which NS/PCs are naturally programmed to respond, into biomaterial scaffolds is discussed with a focus on electrical cues. Next, practical design considerations for conductive biomaterials are discussed followed by a review of studies evaluating how conductive biomaterials can be engineered to control NS/PC behavior by mimicking specific functionalities in the CNS microenvironment. Finally, steps researchers can take to move NS/PC-interfacing, conductive materials closer to clinical translation are discussed.
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Affiliation(s)
| | - Gevick Safarians
- Department of Bioengineering, University of California Los Angeles, USA
| | - Joyce Huang
- Department of Bioengineering, University of California Los Angeles, USA
| | - Bushra Rajput
- Department of Bioengineering, University of California Los Angeles, USA
| | - Jessica Y. Chen
- Department of Bioengineering, University of California Los Angeles, USA
- David Geffen School of Medicine, University of California Los Angeles, USA
| | - Ze Zhong Wang
- Department of Bioengineering, University of California Los Angeles, USA
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14
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Flores Á, López-Santos D, García-Alías G. When Spinal Neuromodulation Meets Sensorimotor Rehabilitation: Lessons Learned From Animal Models to Regain Manual Dexterity After a Spinal Cord Injury. FRONTIERS IN REHABILITATION SCIENCES 2021; 2:755963. [PMID: 36188826 PMCID: PMC9397786 DOI: 10.3389/fresc.2021.755963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/16/2021] [Indexed: 12/22/2022]
Abstract
Electrical neuromodulation has strongly hit the foundations of spinal cord injury and repair. Clinical and experimental studies have demonstrated the ability to neuromodulate and engage spinal cord circuits to recover volitional motor functions lost after the injury. Although the science and technology behind electrical neuromodulation has attracted much of the attention, it cannot be obviated that electrical stimulation must be applied concomitantly to sensorimotor rehabilitation, and one would be very difficult to understand without the other, as both need to be finely tuned to efficiently execute movements. The present review explores the difficulties faced by experimental and clinical neuroscientists when attempting to neuromodulate and rehabilitate manual dexterity in spinal cord injured subjects. From a translational point of view, we will describe the major rehabilitation interventions employed in animal research to promote recovery of forelimb motor function. On the other hand, we will outline some of the state-of-the-art findings when applying electrical neuromodulation to the spinal cord in animal models and human patients, highlighting how evidences from lumbar stimulation are paving the path to cervical neuromodulation.
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Affiliation(s)
- África Flores
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Diego López-Santos
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Guillermo García-Alías
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
- Institut Guttmann de Neurorehabilitació, Badalona, Spain
- *Correspondence: Guillermo García-Alías
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15
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Hachmann JT, Yousak A, Wallner JJ, Gad PN, Edgerton VR, Gorgey AS. Epidural spinal cord stimulation as an intervention for motor recovery after motor complete spinal cord injury. J Neurophysiol 2021; 126:1843-1859. [PMID: 34669485 DOI: 10.1152/jn.00020.2021] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 10/12/2021] [Indexed: 12/19/2022] Open
Abstract
Spinal cord injury (SCI) commonly results in permanent loss of motor, sensory, and autonomic function. Recent clinical studies have shown that epidural spinal cord stimulation may provide a beneficial adjunct for restoring lower extremity and other neurological functions. Herein, we review the recent clinical advances of lumbosacral epidural stimulation for restoration of sensorimotor function in individuals with motor complete SCI and we discuss the putative neural pathways involved in this promising neurorehabilitative approach. We focus on three main sections: review recent clinical results for locomotor restoration in complete SCI; discuss the contemporary understanding of electrical neuromodulation and signal transduction pathways involved in spinal locomotor networks; and review current challenges of motor system modulation and future directions toward integrative neurorestoration. The current understanding is that initial depolarization occurs at the level of large diameter dorsal root proprioceptive afferents that when integrated with interneuronal and latent residual supraspinal translesional connections can recruit locomotor centers and augment downstream motor units. Spinal epidural stimulation can initiate excitability changes in spinal networks and supraspinal networks. Different stimulation parameters can facilitate standing or stepping, and it may also have potential for augmenting myriad other sensorimotor and autonomic functions. More comprehensive investigation of the mechanisms that mediate the transformation of dysfunctional spinal networks to higher functional states with a greater focus on integrated systems-based control system may reveal the key mechanisms underlying neurological augmentation and motor restoration after severe paralysis.
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Affiliation(s)
- Jan T Hachmann
- Department of Neurological Surgery, Virginia Commonwealth University, Richmond, Virginia
| | - Andrew Yousak
- Spinal Cord Injury and Disorders Center, Hunter Holmes McGuire VAMC, Richmond, Virginia
| | - Josephine J Wallner
- Spinal Cord Injury and Disorders Center, Hunter Holmes McGuire VAMC, Richmond, Virginia
| | - Parag N Gad
- Department of Neurobiology, University of California, Los Angeles, California
| | - V Reggie Edgerton
- Department of Neurobiology, University of California, Los Angeles, California
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Badalona, Barcelona, Spain
| | - Ashraf S Gorgey
- Spinal Cord Injury and Disorders Center, Hunter Holmes McGuire VAMC, Richmond, Virginia
- Physical Medicine and Rehabilitation, Virginia Commonwealth University, Richmond, Virginia
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16
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Zhang H, Liu Y, Zhou K, Wei W, Liu Y. Restoring Sensorimotor Function Through Neuromodulation After Spinal Cord Injury: Progress and Remaining Challenges. Front Neurosci 2021; 15:749465. [PMID: 34720867 PMCID: PMC8551759 DOI: 10.3389/fnins.2021.749465] [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] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/13/2021] [Indexed: 12/27/2022] Open
Abstract
Spinal cord injury (SCI) is a major disability that results in motor and sensory impairment and extensive complications for the affected individuals which not only affect the quality of life of the patients but also result in a heavy burden for their families and the health care system. Although there are few clinically effective treatments for SCI, research over the past few decades has resulted in several novel treatment strategies which are related to neuromodulation. Neuromodulation-the use of neuromodulators, electrical stimulation or optogenetics to modulate neuronal activity-can substantially promote the recovery of sensorimotor function after SCI. Recent studies have shown that neuromodulation, in combination with other technologies, can allow paralyzed patients to carry out intentional, controlled movement, and promote sensory recovery. Although such treatments hold promise for completely overcoming SCI, the mechanisms by which neuromodulation has this effect have been difficult to determine. Here we review recent progress relative to electrical neuromodulation and optogenetics neuromodulation. We also examine potential mechanisms by which these methods may restore sensorimotor function. We then highlight the strengths of these approaches and remaining challenges with respect to its application.
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Affiliation(s)
- Hui Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Yaping Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Kai Zhou
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wei Wei
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Yaobo Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
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17
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Hogan MK, Barber SM, Rao Z, Kondiles BR, Huang M, Steele WJ, Yu C, Horner PJ. A wireless spinal stimulation system for ventral activation of the rat cervical spinal cord. Sci Rep 2021; 11:14900. [PMID: 34290260 PMCID: PMC8295294 DOI: 10.1038/s41598-021-94047-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 06/24/2021] [Indexed: 11/09/2022] Open
Abstract
Electrical stimulation of the cervical spinal cord is gaining traction as a therapy following spinal cord injury; however, it is difficult to target the cervical motor region in a rodent using a non-penetrating stimulus compared with direct placement of intraspinal wire electrodes. Penetrating wire electrodes have been explored in rodent and pig models and, while they have proven beneficial in the injured spinal cord, the negative aspects of spinal parenchymal penetration (e.g., gliosis, neural tissue damage, and obdurate inflammation) are of concern when considering therapeutic potential. We therefore designed a novel approach for epidural stimulation of the rat spinal cord using a wireless stimulation system and ventral electrode array. Our approach allowed for preservation of mobility following surgery and was suitable for long term stimulation strategies in awake, freely functioning animals. Further, electrophysiology mapping of the ventral spinal cord revealed the ventral approach was suitable to target muscle groups of the rat forelimb and, at a single electrode lead position, different stimulation protocols could be applied to achieve unique activation patterns of the muscles of the forelimb.
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Affiliation(s)
- Matthew K Hogan
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA.
| | - Sean M Barber
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
| | | | - Bethany R Kondiles
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA.,International Collaboration on Repair Discovories, University of British Columbia, Vancouver, Canada
| | - Meng Huang
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
| | - William J Steele
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
| | | | - Philip J Horner
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
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18
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Malone IG, Nosacka RL, Nash MA, Otto KJ, Dale EA. Electrical epidural stimulation of the cervical spinal cord: implications for spinal respiratory neuroplasticity after spinal cord injury. J Neurophysiol 2021; 126:607-626. [PMID: 34232771 DOI: 10.1152/jn.00625.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Traumatic cervical spinal cord injury (cSCI) can lead to damage of bulbospinal pathways to the respiratory motor nuclei and consequent life-threatening respiratory insufficiency due to respiratory muscle paralysis/paresis. Reports of electrical epidural stimulation (EES) of the lumbosacral spinal cord to enable locomotor function after SCI are encouraging, with some evidence of facilitating neural plasticity. Here, we detail the development and success of EES in recovering locomotor function, with consideration of stimulation parameters and safety measures to develop effective EES protocols. EES is just beginning to be applied in other motor, sensory, and autonomic systems; however, there has only been moderate success in preclinical studies aimed at improving breathing function after cSCI. Thus, we explore the rationale for applying EES to the cervical spinal cord, targeting the phrenic motor nucleus for the restoration of breathing. We also suggest cellular/molecular mechanisms by which EES may induce respiratory plasticity, including a brief examination of sex-related differences in these mechanisms. Finally, we suggest that more attention be paid to the effects of specific electrical parameters that have been used in the development of EES protocols and how that can impact the safety and efficacy for those receiving this therapy. Ultimately, we aim to inform readers about the potential benefits of EES in the phrenic motor system and encourage future studies in this area.
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Affiliation(s)
- Ian G Malone
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida.,Breathing Research and Therapeutics Center (BREATHE), University of Florida, Gainesville, Florida
| | - Rachel L Nosacka
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Marissa A Nash
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Kevin J Otto
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida.,Breathing Research and Therapeutics Center (BREATHE), University of Florida, Gainesville, Florida.,J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida.,Department of Neuroscience, University of Florida, Gainesville, Florida.,Department of Neurology, University of Florida, Gainesville, Florida.,Department of Materials Science and Engineering, University of Florida, Gainesville, Florida.,McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Erica A Dale
- Breathing Research and Therapeutics Center (BREATHE), University of Florida, Gainesville, Florida.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida.,Department of Neuroscience, University of Florida, Gainesville, Florida.,McKnight Brain Institute, University of Florida, Gainesville, Florida
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19
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Samejima S, Khorasani A, Ranganathan V, Nakahara J, Tolley NM, Boissenin A, Shalchyan V, Daliri MR, Smith JR, Moritz CT. Brain-Computer-Spinal Interface Restores Upper Limb Function After Spinal Cord Injury. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1233-1242. [PMID: 34138712 DOI: 10.1109/tnsre.2021.3090269] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Brain-computer interfaces (BCIs) are an emerging strategy for spinal cord injury (SCI) intervention that may be used to reanimate paralyzed limbs. This approach requires decoding movement intention from the brain to control movement-evoking stimulation. Common decoding methods use spike-sorting and require frequent calibration and high computational complexity. Furthermore, most applications of closed-loop stimulation act on peripheral nerves or muscles, resulting in rapid muscle fatigue. Here we show that a local field potential-based BCI can control spinal stimulation and improve forelimb function in rats with cervical SCI. We decoded forelimb movement via multi-channel local field potentials in the sensorimotor cortex using a canonical correlation analysis algorithm. We then used this decoded signal to trigger epidural spinal stimulation and restore forelimb movement. Finally, we implemented this closed-loop algorithm in a miniaturized onboard computing platform. This Brain-Computer-Spinal Interface (BCSI) utilized recording and stimulation approaches already used in separate human applications. Our goal was to demonstrate a potential neuroprosthetic intervention to improve function after upper extremity paralysis.
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20
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Sharma P, Shah PK. In vivo electrophysiological mechanisms underlying cervical epidural stimulation in adult rats. J Physiol 2021; 599:3121-3150. [PMID: 33894695 DOI: 10.1113/jp281146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/15/2021] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS To electrophysiologically determine the predominant neural structures activated with cervical epidural stimulation (ES), well-established electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were delivered at rest, during motor activity and under anaesthesia in adult rats. Cervical ES resulted in spinal evoked motor responses with three different waveforms - early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. In contrast, MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. ERs are consequential to the direct activation of motor efferents; MRs are secondary to type-I sensory afferent activation and LRs result from the engagement of wider spinal interneuronal circuitry with potential influence from supraspinal pathways. Evidence from this work is fundamental in enhancing our understanding of cervical ES, and critical in refining the design of neuromodulation-based rehabilitative strategies and in the construction of neuroprosthetics. ABSTRACT Epidural stimulation (ES) of the lumbar spinal cord has demonstrated significant improvements in various physiological functions after a traumatic spinal cord injury in humans. Electrophysiological evidence from rodent, human and computational studies collectively suggest that the functional recovery following lumbar ES is mediated via direct activation of sensory afferent fibres. However, the mechanisms underlying cervical ES have not been comprehensively studied, which greatly limits our understanding of its effectiveness in restoring upper limb function. In this work, we determined the predominant neural structures that are activated with cervical ES using in vivo cervical spinal evoked motor responses (SEMRs). Standard electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were implemented in 11 awake and anaesthetized rats in four experimental stages. Three distinct types of cervical SEMRs were identified based on latency of their appearance: early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. Except for LRs being completely abolished under urethane, ketamine or urethane anaesthesia did not affect the appearance of cervical SEMRs. Our data, backed by literature, suggest that ERs are secondary to the direct activation of motor efferents, MRs are elicited by activation of type-I sensory afferents and LRs result from the engagement of interneuronal circuitry with potential influence from supraspinal pathways. The gathered information paves the way to designing motor rehabilitation strategies that can utilize cervical ES to recover upper limb function following neurological deficits.
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Affiliation(s)
- Pawan Sharma
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
| | - Prithvi K Shah
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
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21
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Liu H, Xiong D, Pang R, Deng Q, Sun N, Zheng J, Liu J, Xiang W, Chen Z, Lu J, Wang W, Zhang A. Effects of repetitive magnetic stimulation on motor function and GAP43 and 5-HT expression in rats with spinal cord injury. J Int Med Res 2021; 48:300060520970765. [PMID: 33356694 PMCID: PMC7783896 DOI: 10.1177/0300060520970765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Objectives Spinal cord injury (SCI) is a disabling central nervous system disorder. This
study aimed to explore the effects of repetitive trans-spinal magnetic
stimulation (rTSMS) of different spinal cord segments on movement function
and growth-associated protein-43 (GAP43) and 5-hydroxytryptamine (5-HT)
expression in rats after acute SCI and to preliminarily discuss the optimal
rTSMS treatment site to provide a theoretical foundation and experimental
evidence for clinical application of rTSMS in SCI. Methods A rat T10 laminectomy SCI model produced by transient application of an
aneurysm clip was used in the study. The rats were divided into group A
(sham surgery), group B (acute SCI without stimulation), group C (T6 segment
stimulation), group D (T10 segment stimulation), and group E (L2 segment
stimulation). Results In vivo magnetic stimulation protected motor function, alleviated myelin
sheath damage, decreased NgR and Nogo-A expression levels, increased GAP43
and 5-HT expression levels, and inhibited terminal deoxynucleotidyl
transferase dUTP nick end labeling-positive cells and apoptosis-related
protein expression in rats at 8 weeks after the surgery. Conclusions This study suggests that rTSMS can promote GAP43 and 5-HT expression and
axonal regeneration in the spinal cord, which is beneficial to motor
function recovery after acute SCI.
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Affiliation(s)
- Hao Liu
- Department of Rehabilitation, Shanghai Fourth People's Hospital Affiliated with Tongji University School of Medicine, Shanghai, P.R. China.,Department of Rehabilitation, The First Affiliated Hospital of Naval Medical University, Shanghai, P.R. China
| | - Deqi Xiong
- Department of Rehabilitation, The Second People's Hospital of Yibin, Yibin, Sichuan, P.R. China
| | - Rizhao Pang
- Department of Rehabilitation, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
| | - Qian Deng
- School of Medicine, Southwest Jiaotong University, Chengdu, Sichuan, P.R. China
| | - Nianyi Sun
- Department of Rehabilitation, Shengjing Hospital of China Medical University, Shenyang, Liaoning, P.R. China
| | - Jinqi Zheng
- Department of Rehabilitation, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
| | - Jiancheng Liu
- Department of Rehabilitation, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
| | - Wu Xiang
- Department of Rehabilitation, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
| | - Zhesi Chen
- Department of Rehabilitation, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
| | - Jiachun Lu
- Department of Rehabilitation, Chengdu Eighth People's Hospital, Chengdu, Sichuan, P.R. China
| | - Wenchun Wang
- Department of Rehabilitation, The General Hospital of Western Theater Command, Chengdu, Sichuan, P.R. China
| | - Anren Zhang
- Department of Rehabilitation, Shanghai Fourth People's Hospital Affiliated with Tongji University School of Medicine, Shanghai, P.R. China
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22
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Boakye M, Ugiliweneza B, Madrigal F, Mesbah S, Ovechkin A, Angeli C, Bloom O, Wecht JW, Ditterline B, Harel NY, Kirshblum S, Forrest G, Wu S, Harkema S, Guest J. Clinical Trial Designs for Neuromodulation in Chronic Spinal Cord Injury Using Epidural Stimulation. Neuromodulation 2021; 24:405-415. [PMID: 33794042 DOI: 10.1111/ner.13381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/11/2021] [Accepted: 02/09/2021] [Indexed: 12/17/2022]
Abstract
STUDY DESIGN This is a narrative review focused on specific challenges related to adequate controls that arise in neuromodulation clinical trials involving perceptible stimulation and physiological effects of stimulation activation. OBJECTIVES 1) To present the strengths and limitations of available clinical trial research designs for the testing of epidural stimulation to improve recovery after spinal cord injury. 2) To describe how studies can control for the placebo effects that arise due to surgical implantation, the physical presence of the battery, generator, control interfaces, and rehabilitative activity aimed to promote use-dependent plasticity. 3) To mitigate Hawthorne effects that may occur in clinical trials with intensive supervised participation, including rehabilitation. MATERIALS AND METHODS Focused literature review of neuromodulation clinical trials with integration to the specific context of epidural stimulation for persons with chronic spinal cord injury. CONCLUSIONS Standard of care control groups fail to control for the multiple effects of knowledge of having undergone surgical procedures, having implanted stimulation systems, and being observed in a clinical trial. The irreducible effects that have been identified as "placebo" require sham controls or comparison groups in which both are implanted with potentially active devices and undergo similar rehabilitative training.
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Affiliation(s)
- Maxwell Boakye
- Department of Neurological Surgery, University of Louisville, Louisville, KY, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Beatrice Ugiliweneza
- Department of Neurological Surgery, University of Louisville, Louisville, KY, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA.,Department of Health Management and Systems Sciences, University of Louisville, Louisville, KY, USA
| | - Fabian Madrigal
- Department of Neurological Surgery, University of Louisville, Louisville, KY, USA
| | - Samineh Mesbah
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Alexander Ovechkin
- Department of Neurological Surgery, University of Louisville, Louisville, KY, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Claudia Angeli
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA.,Department of Bioengineering, University of Louisville, Louisville, KY, USA.,Frazier Rehabilitation Institute, University of Louisville Health, Louisville, KY, USA
| | - Ona Bloom
- Feinstein Institute for Medical Research, Manhasset, NY, USA.,Department of Molecular Medicine, Zucker School of Medicine at Hofstra Northwell, Manhasset, NY, USA.,Department of Physical Medicine and Rehabilitation, Zucker School of Medicine at Hofstra Northwell, Manhasset, NY, USA.,James J Peters VA Medical Center, Bronx, NY, USA
| | - Jill W Wecht
- James J Peters VA Medical Center, Bronx, NY, USA.,The Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Bonnie Ditterline
- Department of Neurological Surgery, University of Louisville, Louisville, KY, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA
| | - Noam Y Harel
- James J Peters VA Medical Center, Bronx, NY, USA.,The Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Steven Kirshblum
- Kessler Institute for Rehabilitation, Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, NY, USA.,Human Performance and Engineering Research, Kessler Foundation, West Orange, NJ, USA
| | - Gail Forrest
- Human Performance and Engineering Research, Kessler Foundation, West Orange, NJ, USA.,Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Samuel Wu
- Department of Biostatistics, CTSI Data Coordinating Center, University of Florida, Gainesville, FL, USA
| | - Susan Harkema
- Department of Neurological Surgery, University of Louisville, Louisville, KY, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA.,Frazier Rehabilitation Institute, University of Louisville Health, Louisville, KY, USA
| | - James Guest
- Neurological Surgery, and the Miami Project to Cure Paralysis, Miller School of Medicine, Miami, FL, USA
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23
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Jin B, Alam M, Tierno A, Zhong H, Roy RR, Gerasimenko Y, Lu DC, Edgerton VR. Serotonergic Facilitation of Forelimb Functional Recovery in Rats with Cervical Spinal Cord Injury. Neurotherapeutics 2021; 18:1226-1243. [PMID: 33420588 PMCID: PMC8423890 DOI: 10.1007/s13311-020-00974-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2020] [Indexed: 10/22/2022] Open
Abstract
Serotonergic agents can improve the recovery of motor ability after a spinal cord injury. Herein, we compare the effects of buspirone, a 5-HT1A receptor partial agonist, to fluoxetine, a selective serotonin reuptake inhibitor, on forelimb motor function recovery after a C4 bilateral dorsal funiculi crush in adult female rats. After injury, single pellet reaching performance and forelimb muscle activity decreased in all rats. From 1 to 6 weeks after injury, rats were tested on these tasks with and without buspirone (1-2 mg/kg) or fluoxetine (1-5 mg/kg). Reaching and grasping success rates of buspirone-treated rats improved rapidly within 2 weeks after injury and plateaued over the next 4 weeks of testing. Electromyography (EMG) from selected muscles in the dominant forelimb showed that buspirone-treated animals used new reaching strategies to achieve success after the injury. However, forelimb performance dramatically decreased within 2 weeks of buspirone withdrawal. In contrast, fluoxetine treatment resulted in a more progressive rate of improvement in forelimb performance over 8 weeks after injury. Neither buspirone nor fluoxetine significantly improved quadrupedal locomotion on the horizontal ladder test. The improved accuracy of reaching and grasping, patterns of muscle activity, and increased excitability of spinal motor-evoked potentials after buspirone administration reflect extensive reorganization of connectivity within and between supraspinal and spinal sensory-motor netxcopy works. Thus, both serotonergic drugs, buspirone and fluoxetine, neuromodulated these networks to physiological states that enabled markedly improved forelimb function after cervical spinal cord injury.
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Affiliation(s)
- Benita Jin
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA
| | - Monzurul Alam
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA
| | - Alexa Tierno
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA
| | - Hui Zhong
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA
| | - Roland R Roy
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA
- Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Yury Gerasimenko
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA
- Pavlov Institute of Physiology, St. Petersburg, 199034, Russia
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420006, Russia
| | - Daniel C Lu
- Department of Neurosurgery, University of California, Los Angeles, CA, 90095, USA
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive, Los Angeles, CA, 90095-1527, USA.
- Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Neurosurgery, University of California, Los Angeles, CA, 90095, USA.
- Department of Neurobiology, University of California, Los Angeles, CA, 90095, USA.
- Faculty of Science, The Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney, Ultimo, NSW, Australia.
- Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscript a la Universitat Autònoma de Barcelona, 08916, Badalona, Spain.
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24
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Ahmed RU, Edgerton VR, Li S, Zheng YP, Alam M. Buspirone Dose-Response on Facilitating Forelimb Functional Recovery in Cervical Spinal Cord Injured Rats. Dose Response 2021; 19:1559325821998136. [PMID: 33716591 PMCID: PMC7924001 DOI: 10.1177/1559325821998136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 01/26/2021] [Accepted: 02/05/2021] [Indexed: 12/02/2022] Open
Abstract
Buspirone, widely used as a neuropsychiatric drug, has also shown potentials for motor function recovery of injured spinal cord. However, the optimum dosages of such treatment remain unclear. In this study, we investigated the dose-response of Buspirone treatment on reaching and grasping function in cervical cord injured rats. Seventeen adult Sprague-Dawley rats were trained to reach and grasp sugar pellets before a C4 bilateral dorsal column crush injury. After 1 week post-injury, the rats were divided into 3 groups to receive 1 of 3 different dosages of Buspirone (i.p., 1 dose/day: 1.5, n = 5; 2.5, n = 6 and 3.5 mg/kg b.w., n = 6). Forelimb reaching and grip strength test were recorded once per week, within 1 hour of Buspirone administration for 11 weeks post-injury. Different dose groups began to exhibit differences in reaching scores from 4 weeks post-injury. From 4-11 weeks post-injury, the reaching scores were highest in the lowest-dose group rats compared to the other 2 dose groups rats. Average grip strength was also found higher in the lowest-dose rats. Our results demonstrate a significant dose-dependence of Buspirone on the recovery of forelimb motor functions after cervical cord injury with the best performance occurring at the lowest dose tested.
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Affiliation(s)
- Rakib Uddin Ahmed
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - V Reggie Edgerton
- Department of Neurobiology, University of California, Los Angeles, CA, USA.,Department of Neurosurgery, University of California, Los Angeles, CA, USA.,Brain Research Institute, University of California, Los Angeles, CA, USA.,Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Barcelona, Badalona, Spain.,The Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales, Australia
| | - Shuai Li
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Yong-Ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Monzurul Alam
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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25
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Epidural Stimulation Combined with Triple Gene Therapy for Spinal Cord Injury Treatment. Int J Mol Sci 2020; 21:ijms21238896. [PMID: 33255323 PMCID: PMC7734573 DOI: 10.3390/ijms21238896] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/06/2020] [Accepted: 11/17/2020] [Indexed: 12/18/2022] Open
Abstract
The translation of new therapies for spinal cord injury to clinical trials can be facilitated with large animal models close in morpho-physiological scale to humans. Here, we report functional restoration and morphological reorganization after spinal contusion in pigs, following a combined treatment of locomotor training facilitated with epidural electrical stimulation (EES) and cell-mediated triple gene therapy with umbilical cord blood mononuclear cells overexpressing recombinant vascular endothelial growth factor, glial-derived neurotrophic factor, and neural cell adhesion molecule. Preliminary results obtained on a small sample of pigs 2 months after spinal contusion revealed the difference in post-traumatic spinal cord outcomes in control and treated animals. In treated pigs, motor performance was enabled by EES and the corresponding morpho-functional changes in hind limb skeletal muscles were accompanied by the reorganization of the glial cell, the reaction of stress cell, and synaptic proteins. Our data demonstrate effects of combined EES-facilitated motor training and cell-mediated triple gene therapy after spinal contusion in large animals, informing a background for further animal studies and clinical translation.
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26
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Liu J, Yang Z, Wu X, Huang Z, Huang Z, Chen X, Liu Q, Jiang H, Zhu Q. Comparison of the anatomical morphology of cervical vertebrae between humans and macaques: related to a spinal cord injury model. Exp Anim 2020; 70:108-118. [PMID: 33071271 PMCID: PMC7887620 DOI: 10.1538/expanim.20-0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Non-human primates are most suitable for generating cervical experimental models, and it is necessary to study the anatomy of the cervical spine in non-human primates when generating the models. The purpose of this study was to provide the anatomical parameters of the cervical spine and spinal cord in long-tailed macaques (Macaca fascicularis) as a basis for cervical spine-related experimental studies. Cervical spine specimens from 8 male adult subjects were scanned by micro-computed tomography, and an additional 10 live male subjects were scanned by magnetic resonance imaging. The measurements and parameters from them were compared to those of 12 male adult human subjects. Additionally, 10 live male subjects were scanned by magnetic resonance imaging, and the width and depth of the spinal cord and spinal canal and the thickness of the anterior and posterior cerebrospinal fluid were measured and compared to the relevant parameters of 10 male adult human subjects. The tendency of cervical parameters to change with segmental changes was similar between species. The vertebral body, spinal canal, and spinal cord were significantly flatter in the human subjects than in the long-tailed macaques. The cerebrospinal fluid space in the long-tailed macaques was smaller than that in the human subjects. The anatomical features of the cervical vertebrae of long-tailed macaques provide a reference for establishing a preclinical model of cervical spinal cord injury.
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Affiliation(s)
- Junhao Liu
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Zhou Yang
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Xiuhua Wu
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Zucheng Huang
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Zhiping Huang
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Xushi Chen
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Qi Liu
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Hui Jiang
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
| | - Qingan Zhu
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, China
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27
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Hogan MK, Hamilton GF, Horner PJ. Neural Stimulation and Molecular Mechanisms of Plasticity and Regeneration: A Review. Front Cell Neurosci 2020; 14:271. [PMID: 33173465 PMCID: PMC7591397 DOI: 10.3389/fncel.2020.00271] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/31/2020] [Indexed: 12/23/2022] Open
Abstract
Neural stimulation modulates the depolarization of neurons, thereby triggering activity-associated mechanisms of neuronal plasticity. Activity-associated mechanisms in turn play a major role in post-mitotic structure and function of adult neurons. Our understanding of the interactions between neuronal behavior, patterns of neural activity, and the surrounding environment is evolving at a rapid pace. Brain derived neurotrophic factor is a critical mediator of activity-associated plasticity, while multiple immediate early genes mediate plasticity of neurons following bouts of neural activity. New research has uncovered genetic mechanisms that govern the expression of DNA following changes in neural activity patterns, including RNAPII pause-release and activity-associated double stranded breaks. Discovery of novel mechanisms governing activity-associated plasticity of neurons hints at a layered and complex molecular control of neuronal response to depolarization. Importantly, patterns of depolarization in neurons are shown to be important mediators of genetic expression patterns and molecular responses. More research is needed to fully uncover the molecular response of different types of neurons-to-activity patterns; however, known responses might be leveraged to facilitate recovery after neural damage. Physical rehabilitation through passive or active exercise modulates neurotrophic factor expression in the brain and spinal cord and can initiate cortical plasticity commensurate with functional recovery. Rehabilitation likely relies on activity-associated mechanisms; however, it may be limited in its application. Electrical and magnetic stimulation direct specific activity patterns not accessible through passive or active exercise and work synergistically to improve standing, walking, and forelimb use after injury. Here, we review emerging concepts in the molecular mechanisms of activity-derived plasticity in order to highlight opportunities that could add value to therapeutic protocols for promoting recovery of function after trauma, disease, or age-related functional decline.
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Affiliation(s)
- Matthew K Hogan
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, United States
| | - Gillian F Hamilton
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, United States
| | - Philip J Horner
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, United States
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28
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Hou J, Nelson R, Mohammad N, Mustafa G, Plant D, Thompson FJ, Bose P. Effect of Simultaneous Combined Treadmill Training and Magnetic Stimulation on Spasticity and Gait Impairments after Cervical Spinal Cord Injury. J Neurotrauma 2020; 37:1999-2013. [DOI: 10.1089/neu.2019.6961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Jiamei Hou
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Rachel Nelson
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Naweed Mohammad
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Golam Mustafa
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Daniel Plant
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Floyd J. Thompson
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
- Department of Neuroscience, University of Florida, Gainesville, Florida, USA
| | - Prodip Bose
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
- Department of Anesthesiology, University of Florida, Gainesville, Florida, USA
- Department of Neurology, University of Florida, Gainesville, Florida, USA
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29
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Cortical and Subcortical Effects of Transcutaneous Spinal Cord Stimulation in Humans with Tetraplegia. J Neurosci 2020; 40:2633-2643. [PMID: 31996455 DOI: 10.1523/jneurosci.2374-19.2020] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/09/2020] [Accepted: 01/17/2020] [Indexed: 11/21/2022] Open
Abstract
An increasing number of studies supports the view that transcutaneous electrical stimulation of the spinal cord (TESS) promotes functional recovery in humans with spinal cord injury (SCI). However, the neural mechanisms contributing to these effects remain poorly understood. Here we examined motor-evoked potentials in arm muscles elicited by cortical and subcortical stimulation of corticospinal axons before and after 20 min of TESS (30 Hz pulses with a 5 kHz carrier frequency) and sham-TESS applied between C5 and C6 spinous processes in males and females with and without chronic incomplete cervical SCI. The amplitude of subcortical, but not cortical, motor-evoked potentials increased in proximal and distal arm muscles for 75 min after TESS, but not sham-TESS, in control subjects and SCI participants, suggesting a subcortical origin for these effects. Intracortical inhibition, elicited by paired stimuli, increased after TESS in both groups. When TESS was applied without the 5 kHz carrier frequency both subcortical and cortical motor-evoked potentials were facilitated without changing intracortical inhibition, suggesting that the 5 kHz carrier frequency contributed to the cortical inhibitory effects. Hand and arm function improved largely when TESS was used with, compared with without, the 5 kHz carrier frequency. These novel observations demonstrate that TESS influences cortical and spinal networks, having an excitatory effect at the spinal level and an inhibitory effect at the cortical level. We hypothesized that these parallel effects contribute to further the recovery of limb function following SCI.SIGNIFICANCE STATEMENT Accumulating evidence supports the view that transcutaneous electrical stimulation of the spinal cord (TESS) promotes recovery of function in humans with spinal cord injury (SCI). Here, we show that a single session of TESS over the cervical spinal cord in individuals with incomplete chronic cervical SCI influenced in parallel the excitability cortical and spinal networks, having an excitatory effect at the spinal level and an inhibitory effect at the cortical level. Importantly, these parallel physiological effects had an impact on the magnitude of improvements in voluntary motor output.
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30
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Castillo-Escario Y, Rodriguez-Canon M, Garcia-Alias G, Jane R. Onset Detection to Study Muscle Activity in Reaching and Grasping Movements in Rats. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:5113-5116. [PMID: 31947009 DOI: 10.1109/embc.2019.8857200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
EMG signals reflect the neuromuscular activation patterns related to the execution of a certain movement or task. In this work, we focus on reaching and grasping (R&G) movements in rats. Our objective is to develop an automatic algorithm to detect the onsets and offsets of muscle activity and use it to study muscle latencies in R&G maneuvers. We had a dataset of intramuscular EMG signals containing 51 R&G attempts from 2 different animals. Simultaneous video recordings were used for segmentation and comparison. We developed an automatic onset/offset detector based on the ratio of local maxima of Teager-Kaiser Energy (TKE). Then, we applied it to compute muscle latencies and other features related to the muscle activation pattern during R&G cycles. The automatic onsets that we found were consistent with visual inspection and video labels. Despite the variability between attempts and animals, the two rats shared a sequential pattern of muscle activations. Statistical tests confirmed the differences between the latencies of the studied muscles during R&G tasks. This work provides an automatic tool to detect EMG onsets and offsets and conducts a preliminary characterization of muscle activation during R&G movements in rats. This kind of approaches and data processing algorithms can facilitate the studies on upper limb motor control and motor impairment after spinal cord injury or stroke.
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31
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Chia R, Zhong H, Vissel B, Edgerton VR, Gad P. Novel Activity Detection Algorithm to Characterize Spontaneous Stepping During Multimodal Spinal Neuromodulation After Mid-Thoracic Spinal Cord Injury in Rats. Front Syst Neurosci 2020; 13:82. [PMID: 32009910 PMCID: PMC6974470 DOI: 10.3389/fnsys.2019.00082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/16/2019] [Indexed: 12/18/2022] Open
Abstract
A mid-thoracic spinal cord injury (SCI) severely impairs activation of the lower limb sensorimotor spinal networks, leading to paralysis. Various neuromodulatory techniques including electrical and pharmacological activation of the spinal networks have been successful in restoring locomotor function after SCI. We hypothesized that the combination of self-training in a natural environment with epidural stimulation (ES), quipazine (Quip), and strychnine (Strych) would result in greater activity in a cage environment after paralysis compared to either intervention alone. To assess this, we developed a method measuring and characterizing the chronic EMG recordings from tibialis anterior (TA) and soleus (Sol) muscles while rats were freely moving in their home cages. We then assessed the relationship between the change in recorded activity over time and motor-evoked potentials (MEPs) in animals receiving treatments. We found that the combination of ES, Quip, and Strych (sqES) generated the greatest level of recovery followed by ES + Quip (qES) while ES + Strych (sES) and ES alone showed least improvement in recorded activity. Further, we observed an exponential relationship between late response (LR) component of the MEPs and spontaneously generated step-like activity. Our data demonstrate the feasibility and potential importance of quantitatively monitoring mechanistic factors linked to activity-dependence in response to combinatorial interventions compared to individual therapies after SCI.
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Affiliation(s)
- Raymond Chia
- Faculty of Science, Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney, Sydney, NSW, Australia.,St Vincent's Centre for Applied Medical Research, Sydney, NSW, Australia
| | - Hui Zhong
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bryce Vissel
- Faculty of Science, Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney, Sydney, NSW, Australia.,St Vincent's Centre for Applied Medical Research, Sydney, NSW, Australia
| | - V Reggie Edgerton
- Faculty of Science, Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney, Sydney, NSW, Australia.,Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari Adscrit a la Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Parag Gad
- Faculty of Science, Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney, Sydney, NSW, Australia.,Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, United States
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32
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Ghane N, Beigi MH, Labbaf S, Nasr-Esfahani MH, Kiani A. Design of hydrogel-based scaffolds for the treatment of spinal cord injuries. J Mater Chem B 2020; 8:10712-10738. [DOI: 10.1039/d0tb01842b] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hydrogel-based scaffold design approaches for the treatment of spinal cord injuries.
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Affiliation(s)
- Nazanin Ghane
- Department of Cellular Biotechnology Cell Science Research Center
- Royan Institute for Biotechnology
- ACECR
- Isfahan
- Iran
| | - Mohammad-Hossein Beigi
- Department of Cellular Biotechnology Cell Science Research Center
- Royan Institute for Biotechnology
- ACECR
- Isfahan
- Iran
| | - Sheyda Labbaf
- Biomaterials Research Group
- Department of Materials Engineering
- Isfahan University of Technology
- Isfahan
- Iran
| | | | - Amirkianoosh Kiani
- Silicon Hall: Micro/Nano Manufacturing Facility
- Faculty of Engineering and Applied Science
- Ontario Tech University
- Ontario
- Canada
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33
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Barss TS, Parhizi B, Mushahwar VK. Transcutaneous spinal cord stimulation of the cervical cord modulates lumbar networks. J Neurophysiol 2020; 123:158-166. [DOI: 10.1152/jn.00433.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been established that coordinated arm and leg (A&L) cycling facilitates corticospinal drive and modulation of cervico-lumbar connectivity and ultimately improves overground walking in people with incomplete spinal cord injury or stroke. This study examined the effect of noninvasive transcutaneous spinal cord stimulation (tSCS) on the modulation of cervico-lumbar connectivity. Thirteen neurologically intact adults participated in the study. The excitability of the Hoffmann (H) reflex elicited in the soleus muscle was examined under multiple conditions involving either the arms held in a static position or rhythmic arm cycling while tSCS was applied to either the cervical or lumbar cord. As expected, soleus H-reflex amplitude was significantly suppressed by 19.2% during arm cycling (without tSCS) relative to arms static (without tSCS). Interestingly, tSCS of the cervical cord with arms static significantly suppressed the soleus H-reflex (−22.9%), whereas tSCS over the lumbar cord did not suppress the soleus H-reflex (−3.8%). The combination of arm cycling with cervical or lumbar tSCS did not yield additional suppression of the soleus H-reflex beyond that obtained with arm cycling alone or cervical tSCS alone. The results demonstrate that activation of the cervical spinal cord through both rhythmic arm cycling and tonic tSCS significantly modulates the activity of lumbar networks. This highlights the potential for engaging cervical spinal cord networks through tSCS during rehabilitation interventions to enhance cervico-lumbar connectivity. This connectivity is influential in facilitating improvements in walking function after neurological impairment. NEW & NOTEWORTHY This is the first study to investigate the modulatory effects of transcutaneous spinal cord stimulation (tSCS) on cervico-lumbar connectivity. We report that both rhythmic activation of the cervical spinal cord through arm cycling and tonic activation of the cervical cord through tSCS significantly modulate the activity of lumbar networks. This suggests that engaging cervical spinal cord networks through tSCS during locomotor retraining interventions may not only enhance cervico-lumbar connectivity but also further improve walking capacity.
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Affiliation(s)
- Trevor S. Barss
- Neuroscience and Mental Health Institute, University of Alberta, AB, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, AB, Canada
| | - Behdad Parhizi
- Neuroscience and Mental Health Institute, University of Alberta, AB, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, AB, Canada
| | - Vivian K. Mushahwar
- Neuroscience and Mental Health Institute, University of Alberta, AB, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, AB, Canada
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34
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Torres-Espín A, Beaudry E, Fenrich K, Fouad K. Rehabilitative Training in Animal Models of Spinal Cord Injury. J Neurotrauma 2019; 35:1970-1985. [PMID: 30074874 DOI: 10.1089/neu.2018.5906] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rehabilitative motor training is currently one of the most widely used approaches to promote moderate recovery following injuries of the central nervous system. Such training is generally applied in the clinical setting, whereas it is not standard in preclinical research. This is a concern as it is becoming increasingly apparent that neuroplasticity enhancing treatments require training or some form of activity as a co-therapy to promote functional recovery. Despite the importance of training and the many open questions regarding its mechanistic consequences, its use in preclinical animal models is rather limited. Here we review approaches, findings and challenges when training is applied in animal models of spinal cord injury, and we suggest recommendations to facilitate the integration of training using an appropriate study design, into pre-clinical studies.
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Affiliation(s)
- Abel Torres-Espín
- Faculty of Rehabilitation Medicine and Institute for Neuroscience and Mental Health, University of Alberta , Edmonton, Alberta, Canada
| | - Eric Beaudry
- Faculty of Rehabilitation Medicine and Institute for Neuroscience and Mental Health, University of Alberta , Edmonton, Alberta, Canada
| | | | - Karim Fouad
- Faculty of Rehabilitation Medicine and Institute for Neuroscience and Mental Health, University of Alberta , Edmonton, Alberta, Canada
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Sliow A, Ma Z, Gargiulo G, Mahns D, Mawad D, Breen P, Stoodley M, Houang J, Kuchel R, Tettamanzi GC, Tilley RD, Frost SJ, Morley J, Longo L, Lauto A. Stimulation and Repair of Peripheral Nerves Using Bioadhesive Graft-Antenna. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1801212. [PMID: 31179205 PMCID: PMC6548953 DOI: 10.1002/advs.201801212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/05/2019] [Indexed: 06/09/2023]
Abstract
An original wireless stimulator for peripheral nerves based on a metal loop (diameter ≈1 mm) that is powered by a transcranial magnetic stimulator (TMS) and does not require circuitry components is reported. The loop can be integrated in a chitosan scaffold that functions as a graft when applied onto transected nerves (graft-antenna). The graft-antenna is bonded to rat sciatic nerves by a laser without sutures; it does not migrate after implantation and is able to trigger steady compound muscle action potentials for 12 weeks (CMAP ≈1.3 mV). Eight weeks postoperatively, axon regeneration is facilitated in transected nerves that are repaired with the graft-antenna and stimulated by the TMS for 1 h per week. The graft-antenna is an innovative and minimally-invasive device that functions concurrently as a wireless stimulator and adhesive scaffold for nerve repair.
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Affiliation(s)
- Ashour Sliow
- School of Science and HealthWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Zhi Ma
- School of MedicineWestern Sydney UniversityPenrithNSW2751Australia
| | - Gaetano Gargiulo
- Biomedical Engineering & Neuroscience Research GroupMARCS InstituteWestern Sydney UniversityPenrithNSW2751Australia
| | - David Mahns
- School of MedicineWestern Sydney UniversityPenrithNSW2751Australia
| | - Damia Mawad
- School of Materials Science and EngineeringUniversity of New South WalesKensingtonNSW2052Australia
| | - Paul Breen
- Biomedical Engineering & Neuroscience Research GroupMARCS InstituteWestern Sydney UniversityPenrithNSW2751Australia
| | - Marcus Stoodley
- The Australian School of Advanced MedicineMacquarie UniversityNorth RydeNSW2109Australia
| | - Jessica Houang
- School of Aerospace, Mechanical and Mechatronic EngineeringUniversity of SydneySydneyNSW2006Australia
| | - Rhiannon Kuchel
- Mark Wainwright Analytical CentreUniversity of New South WalesKensingtonNSW2052Australia
| | - Giuseppe C. Tettamanzi
- School of Physical Sciences and Institute for Photonics and Advanced SensingUniversity of AdelaideAdelaideSA5005Australia
| | - Richard D. Tilley
- Mark Wainwright Analytical CentreUniversity of New South WalesKensingtonNSW2052Australia
| | - Samuel J. Frost
- School of Science and HealthWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - John Morley
- School of MedicineWestern Sydney UniversityPenrithNSW2751Australia
| | - Leonardo Longo
- Faculty of Human SciencesUniversity of the Republic of San MarinoContrada Omerelli47890Republic of San Marino
| | - Antonio Lauto
- School of Science and HealthWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
- School of MedicineWestern Sydney UniversityPenrithNSW2751Australia
- Biomedical Engineering & Neuroscience Research GroupMARCS InstituteWestern Sydney UniversityPenrithNSW2751Australia
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Ahmed RU, Alam M, Zheng YP. Experimental spinal cord injury and behavioral tests in laboratory rats. Heliyon 2019; 5:e01324. [PMID: 30906898 PMCID: PMC6411514 DOI: 10.1016/j.heliyon.2019.e01324] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/01/2018] [Accepted: 03/04/2019] [Indexed: 12/15/2022] Open
Abstract
Traumatic spinal cord injury (SCI) results in some serious neurophysiological consequences that alter healthy body functions and devastate the quality of living of individuals. To find a cure for SCI, researchers around the world are working on different neurorepair and neurorehabilitation modalities. To test a new treatment for SCI as well as to understand the mechanism of recovery, animal models are being widely used. Among them, SCI rat models are arguably the most prominent. Furthermore, it is important to select a suitable behavioral test to evaluate both the motor and sensory recovery following any therapeutic intervention. In this paper, we review the rat models of spinal injury and commonly used behavioral tests to serve as a useful guideline for neuroscientists in the field of SCI research.
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Affiliation(s)
- Rakib Uddin Ahmed
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong
| | - Monzurul Alam
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong
| | - Yong-Ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong
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Calvert JS, Grahn PJ, Zhao KD, Lee KH. Emergence of Epidural Electrical Stimulation to Facilitate Sensorimotor Network Functionality After Spinal Cord Injury. Neuromodulation 2019; 22:244-252. [PMID: 30840354 DOI: 10.1111/ner.12938] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 01/15/2019] [Accepted: 01/19/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Traumatic spinal cord injury (SCI) disrupts signaling pathways between the brain and spinal networks below the level of injury. In cases of severe SCI, permanent loss of sensorimotor and autonomic function can occur. The standard of care for severe SCI uses compensation strategies to maximize independence during activities of daily living while living with chronic SCI-related dysfunctions. Over the past several years, the research field of spinal neuromodulation has generated promising results that hold potential to enable recovery of functions via epidural electrical stimulation (EES). METHODS This review provides a historical account of the translational research efforts that led to the emergence of EES of the spinal cord to enable intentional control of motor functions that were lost after SCI. We also highlight the major limitations associated with EES after SCI and propose future directions of spinal neuromodulation research. RESULTS Multiple, independent studies have demonstrated return of motor function via EES in individuals with chronic SCI. These enabled motor functions include intentional, controlled movement of previously paralyzed extremities, independent standing and stepping, and increased grip strength. In addition, improvements in cardiovascular health, respiratory function, body composition, and urologic function have been reported. CONCLUSIONS EES holds promise to enable functions thought to be permanently lost due to SCI. However, EES is currently restricted to scientific investigation in humans with SCI and requires further validation of factors such as safety and efficacy before clinical translation.
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Affiliation(s)
| | - Peter J Grahn
- Department of Neurologic Surgery, Rochester, MN, USA.,Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Rochester, MN, USA
| | - Kristin D Zhao
- Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Kendall H Lee
- Department of Neurologic Surgery, Rochester, MN, USA.,Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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Freyvert Y, Yong NA, Morikawa E, Zdunowski S, Sarino ME, Gerasimenko Y, Edgerton VR, Lu DC. Engaging cervical spinal circuitry with non-invasive spinal stimulation and buspirone to restore hand function in chronic motor complete patients. Sci Rep 2018; 8:15546. [PMID: 30341390 PMCID: PMC6195617 DOI: 10.1038/s41598-018-33123-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/17/2018] [Indexed: 01/01/2023] Open
Abstract
The combined effects of cervical electrical stimulation alone or in combination with the monoaminergic agonist buspirone on upper limb motor function were determined in six subjects with motor complete (AIS B) injury at C5 or above and more than one year from time of injury. Voluntary upper limb function was evaluated through measures of controlled hand contraction, handgrip force production, dexterity measures, and validated clinical assessment batteries. Repeated measure analysis of variance was used to evaluate functional metrics, EMG amplitude, and changes in mean grip strength. In aggregate, mean hand strength increased by greater than 300% with transcutaneous electrical stimulation and buspirone while a corresponding clinically significant improvement was observed in upper extremity motor scores and the action research arm test. Some functional improvements persisted for an extended period after the study interventions were discontinued. We demonstrate that, with these novel interventions, cervical spinal circuitry can be neuromodulated to improve volitional control of hand function in tetraplegic subjects. The potential impact of these findings on individuals with upper limb paralysis could be dramatic functionally, psychologically, and economically.
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Affiliation(s)
- Yevgeniy Freyvert
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Nicholas Au Yong
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Erika Morikawa
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Sharon Zdunowski
- Departments of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Melanie E Sarino
- Rancho Los Amigos National Rehabilitation Center, Downey, California, 90242, USA
| | - Yury Gerasimenko
- Departments of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Pavlov Institute of Physiology, St. Petersburg, Russia
| | - V Reggie Edgerton
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Departments of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Neurobiology, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Brain Research Institute, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Daniel C Lu
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California, 90095, USA.
- Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, 90095, USA.
- Brain Research Institute, University of California, Los Angeles, Los Angeles, California, 90095, USA.
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A Proof-of-Concept Study of Transcutaneous Magnetic Spinal Cord Stimulation for Neurogenic Bladder. Sci Rep 2018; 8:12549. [PMID: 30135433 PMCID: PMC6105631 DOI: 10.1038/s41598-018-30232-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023] Open
Abstract
Patients with chronic spinal cord injury (SCI) cannot urinate at will and must empty the bladder by self-catheterization. We tested the hypothesis that non-invasive, transcutaneous magnetic spinal cord stimulation (TMSCS) would improve bladder function in individuals with SCI. Five individuals with American Spinal Injury Association Impairment Scale A/B, chronic SCI and detrusor sphincter dyssynergia enrolled in this prospective, interventional study. After a two-week assessment to determine effective stimulation characteristics, each patient received sixteen weekly TMSCS treatments and then received “sham” weekly stimulation for six weeks while bladder function was monitored. Bladder function improved in all five subjects, but only during and after repeated weekly sessions of 1 Hz TMSCS. All subjects achieved volitional urination. The volume of urine produced voluntarily increased from 0 cc/day to 1120 cc/day (p = 0.03); self-catheterization frequency decreased from 6.6/day to 2.4/day (p = 0.04); the capacity of the bladder increased from 244 ml to 404 ml (p = 0.02); and the average quality of life ranking increased significantly (p = 0.007). Volitional bladder function was re-enabled in five individuals with SCI following intermittent, non-invasive TMSCS. We conclude that neuromodulation of spinal micturition circuitry by TMSCS may be used to ameliorate bladder function.
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Rascoe A, Sharma P, Shah PK. Development of an Activity-Dependent Epidural Stimulation System in Freely Moving Spinal Cord Injured Rats: A Proof of Concept Study. Front Neurosci 2018; 12:472. [PMID: 30083089 PMCID: PMC6064745 DOI: 10.3389/fnins.2018.00472] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 06/21/2018] [Indexed: 11/13/2022] Open
Abstract
Purpose: Extensive pre-clinical and clinical experimentation has yielded data on the robustness and versatility of epidural stimulation (ES) strategies to activate spinal neural circuitry to produce functional benefits. Increasing studies are now reporting that closed-loop electrical stimulation delivery methods significantly enhance the neuromodulation effects of stimulation, to in turn, improve physiological outcomes of the intervention. No studies have yet explored the feasibility and usage of closed-loop systems to neuromodulate the cervical spinal cord using ES. Methods: We developed an activity-dependent system that utilizes electromyography (EMG) activity to trigger epidural stimulation (tES) of the cervical spinal cord in awake, freely moving rats. Experiments were performed on rats that were implanted with chronic forelimb EMG and cervical epidural implants, with (n = 7) and without (n = 2) a complete C4 spinal hemisection. Results: Our results show that the EMG triggered activity-dependent system can be reliably applied and reproduced for: (i) stimulating multiple rats simultaneously throughout the night during free home-cage activity and (ii) use as a mobile system for testing and training during various short-term behavioral testing conditions. The system was able to consistently generate stimulation pulse trains in response to attempted EMG activity that crossed a user-defined threshold in all rats for all experiments, including the overnight experiments that lasts for 7 h/session for 6 days/week through the 3-month period. Conclusion: The developed closed-loop system can be considered to represent a class of bidirectional neural prostheses via a circuit that enables two-way interactions between neural activity (real-time processing of EMG activity) and external devices (such as a stimulator). It can operate autonomously for extended periods of time in unrestrained rats, allowing its use as a long-term therapeutic tool. It can also enable us to study the long-term physiological effects of incorporating electrical stimulation techniques into the nervous system. The system can also be experimented for connecting several neural systems into a Brainet by combining neural signals from multiple rats dynamically and in real-time so as to enhance motor performance. Studies are ongoing in our laboratory to test the usefulness of this system in the recovery of hand function after cervical spinal cord injuries.
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Affiliation(s)
- Avi Rascoe
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, United States.,Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, United States
| | - Pawan Sharma
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, United States
| | - Prithvi K Shah
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, United States.,Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, United States
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Abstract
Recent advances in neuroscience and devices are ushering in a new generation of medical treatments. Engineered biodevices are demonstrating the potential to create long-term changes in neural circuits, termed neuroplasticity. Thus, the approach of engineering neuroplasticity is rapidly expanding, building on recent demonstrations of improved quality of life for people with movement disorders, epilepsy, and spinal cord injury. In addition, discovering the fundamental mechanisms of engineered neuroplasticity by leveraging anatomically well-documented systems like the spinal cord is likely to provide powerful insights into solutions for other neurotraumas, such as stroke and traumatic brain injury, as well as neurodegenerative disorders, such as Alzheimer's, Parkinson disease, and multiple sclerosis. Now is the time for advancing both the experimental neuroscience, device development, and pioneering human trials to reap the benefits of engineered neuroplasticity as a therapeutic approach for improving quality of life after spinal cord injury.
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Affiliation(s)
- Chet T Moritz
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Washington, Seattle, WA, USA.
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, USA.
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, USA.
- UW Institute of Neuroengineering (UWIN), University of Washington, Seattle, WA, USA.
- Washington Spinal Cord Injury Consortium, University of Washington, Seattle, WA, USA.
- Center for Sensorimotor Neural Engineering, Seattle, WA, USA.
- Department of Electrical Engineering, University of Washington , Box 356490, Seattle, WA, 98195, USA.
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43
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Bączyk M, Jankowska E. Long-term effects of direct current are reproduced by intermittent depolarization of myelinated nerve fibers. J Neurophysiol 2018; 120:1173-1185. [PMID: 29924713 DOI: 10.1152/jn.00236.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Direct current (DC) potently increases the excitability of myelinated afferent fibers in the dorsal columns, both during DC polarization of these fibers and during a considerable (>1 h) postpolarization period. The aim of the present study was to investigate whether similarly long-lasting changes in the excitability of myelinated nerve fibers in the dorsal columns may be evoked by field potentials following stimulation of peripheral afferents and by subthreshold epidurally applied current pulses. The experiments were performed in deeply anesthetized rats. The effects were monitored by changes in nerve volleys evoked in epidurally stimulated hindlimb afferents and in the synaptic actions of these afferents. Both were found to be facilitated during as well as following stimulation of a skin nerve and during as well as following epidurally applied current pulses of 5- to 10-ms duration. The facilitation occurring ≤2 min after skin nerve stimulation could be linked to both primary afferent depolarization and large dorsal horn field potentials, whereas the subsequent changes (up to 1 h) were attributable to effects of the field potentials. The findings lead to the conclusion that the modulation of spinal activity evoked by DC does not require long-lasting polarization and that relatively short current pulses and intrinsic field potentials may contribute to plasticity in spinal activity. These results suggest the possibility of enhancing the effects of epidural stimulation in human subjects by combining it with polarizing current pulses and peripheral afferent stimulation and not only with continuous DC. NEW & NOTEWORTHY The aim of this study was to define conditions under which a long-term increase is evoked in the excitability of myelinated nerve fibers. The results demonstrate that a potent and long-lasting increase in the excitability of afferent fibers traversing the dorsal columns may be induced by synaptically evoked intrinsic field as well as by epidurally applied intermittent current pulses. They thus provide a new means for the facilitation of the effects of epidural stimulation.
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Affiliation(s)
- M Bączyk
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden.,Department of Neurobiology, Poznań University of Physical Education , Poznań , Poland
| | - E Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden
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Garcia-Sandoval A, Pal A, Mishra AM, Sherman S, Parikh AR, Joshi-Imre A, Arreaga-Salas D, Gutierrez-Heredia G, Duran-Martinez AC, Nathan J, Hosseini SM, Carmel JB, Voit W. Chronic softening spinal cord stimulation arrays. J Neural Eng 2018; 15:045002. [PMID: 29569573 DOI: 10.1088/1741-2552/aab90d] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE We sought to develop a cervical spinal cord stimulator for the rat that is durable, stable, and does not perturb the underlying spinal cord. APPROACH We created a softening spinal cord stimulation (SCS) array made from shape memory polymer (SMP)-based flexible electronics. We developed a new photolithographic process to pattern high surface area titanium nitride (TiN) electrodes onto gold (Au) interconnects. The thiol-ene acrylate polymers are stiff at room temperature and soften following implantation into the body. Durability was measured by the duration the devices produced effective stimulation and by accelerated aging in vitro. Stability was measured by the threshold to provoke an electromyogram (EMG) muscle response and by measuring impedance using electrochemical impedance spectroscopy (EIS). In addition, spinal cord modulation of motor cortex potentials was measured. The spinal column and implanted arrays were imaged with MRI ex vivo, and histology for astrogliosis and immune reaction was performed. MAIN RESULTS For durability, the design of the arrays was modified over three generations to create an array that demonstrated activity up to 29 weeks. SCS arrays showed no significant degradation over a simulated 29 week period of accelerated aging. For stability, the threshold for provoking an EMG rose in the first few weeks and then remained stable out to 16 weeks; the impedance showed a similar rise early with stability thereafter. Spinal cord stimulation strongly enhanced motor cortex potentials throughout. Upon explantation, device performance returned to pre-implant levels, indicating that biotic rather than abiotic processes were the cause of changing metrics. MRI and histology showed that softening SCS produced less tissue deformation than Parylene-C arrays. There was no significant astrogliosis or immune reaction to either type of array. SIGNIFICANCE Softening SCS arrays meet the needs for research-grade devices in rats and could be developed into human devices in the future.
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Affiliation(s)
- Aldo Garcia-Sandoval
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX 75080, United States of America
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Li J, Chen S, Zhao Z, Luo Y, Hou Y, Li H, He L, Zhou L, Wu W. Effect of VEGF on Inflammatory Regulation, Neural Survival, and Functional Improvement in Rats following a Complete Spinal Cord Transection. Front Cell Neurosci 2017; 11:381. [PMID: 29238292 PMCID: PMC5712574 DOI: 10.3389/fncel.2017.00381] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/14/2017] [Indexed: 11/13/2022] Open
Abstract
After complete transection of the thoracic spinal segment, neonatal rats exhibit spontaneous locomotor recovery of hindlimbs, but this recovery is not found in adult rats after similar injury. The potential mechanism related to the difference in recovery of neonatal and adult rats remains unknown. In this study, 342 animals were analyzed. The vascular endothelial growth factor (VEGF) level in spinal segments below injury sites was significantly higher in postnatal day 1 rats (P1) compared with 28-day-old adult rats (P28) following a complete T9 transection. VEGF administration in P28 rats with T9 transection significantly improved the functional recovery; by contrast, treatment with VEGF receptor inhibitors in P1 rats with T9 transection slowed down the spontaneous functional recovery. Results showed more neurons reduced in the lumbar spinal cord and worse local neural network reorganization below injury sites in P28 rats than those in P1 rats. Transynaptic tracing with pseudorabies virus and double immunofluorescence analysis indicated that VEGF treatment in P28 rats alleviated the reduced number of neurons and improved their network reorganization. VEGF inhibition in neonates resulted in high neuronal death rate and deteriorated network reorganization. In in vivo studies, T9 transection induced less increase in the number of microglia in the spinal cord in P1 animals than P28 animals. VEGF treatment reduced the increase in microglial cells in P28 animals. VEGF administration in cultured spinal motoneurons prevented lipopolysaccharide (LPS)-induced neuronal death and facilitated neurite growth. Western blots of the samples of lumbar spinal cord after spinal transection and cultured spinal motoneurons showed a lower level of Erk1/2 phosphorylation after the injury or LPS induction compared with that in the control. The phosphorylation level increased after VEGF treatment. In conclusion, VEGF is a critical mediator involved in functional recovery after spinal transection and can be considered a potential target for clinical therapy.
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Affiliation(s)
- Jing Li
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
- Department of Anatomy, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Shuangxi Chen
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Zhikai Zhao
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Yunhao Luo
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Yuhui Hou
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Heng Li
- Department of Anatomy, University of Hong Kong, Hong Kong, Hong Kong
| | - Liumin He
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Libing Zhou
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Wutian Wu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
- Department of Anatomy, University of Hong Kong, Hong Kong, Hong Kong
- Re-Stem Biotechnology Co., Ltd., Suzhou, China
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Kuck A, Stegeman DF, van Asseldonk EHF. Modeling trans-spinal direct current stimulation for the modulation of the lumbar spinal motor pathways. J Neural Eng 2017. [PMID: 28631619 DOI: 10.1088/1741-2552/aa7960] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Trans-spinal direct current stimulation (tsDCS) is a potential new technique for the treatment of spinal cord injury (SCI). TsDCS aims to facilitate plastic changes in the neural pathways of the spinal cord with a positive effect on SCI recovery. To establish tsDCS as a possible treatment option for SCI, it is essential to gain a better understanding of its cause and effects. We seek to understand the acute effect of tsDCS, including the generated electric field (EF) and its polarization effect on the spinal circuits, to determine a cellular target. We further ask how these findings can be interpreted to explain published experimental results. APPROACH We use a realistic full body finite element volume conductor model to calculate the EF of a 2.5 mA direct current for three different electrode configurations. We apply the calculated electric field to realistic motoneuron models to investigate static changes in membrane resting potential. The results are combined with existing knowledge about the theoretical effect on a neuronal level and implemented into an existing lumbar spinal network model to simulate the resulting changes on a network level. MAIN RESULTS Across electrode configurations, the maximum EF inside the spinal cord ranged from 0.47 V m-1 to 0.82 V m-1. Axon terminal polarization was identified to be the dominant cellular target. Also, differences in electrode placement have a large influence on axon terminal polarization. Comparison between the simulated acute effects and the electrophysiological long-term changes observed in human tsDCS studies suggest an inverse relationship between the two. SIGNIFICANCE We provide methods and knowledge for better understanding the effects of tsDCS and serve as a basis for a more targeted and optimized application of tsDCS.
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Affiliation(s)
- A Kuck
- University of Twente, Drienerlolaan 5, 7522 NB Enschede, Netherlands
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