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Benevides ES, Thakre PP, Rana S, Sunshine MD, Jensen VN, Oweiss K, Fuller DD. Chemogenetic stimulation of phrenic motor output and diaphragm activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589188. [PMID: 38659846 PMCID: PMC11042184 DOI: 10.1101/2024.04.12.589188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Impaired diaphragm activation contributes to morbidity and mortality in many neurodegenerative diseases and neurologic injuries. We conducted experiments to determine if expression of an excitatory DREADD (designer receptors exclusively activation by designer drugs) in the mid-cervical spinal cord would enable respiratory-related activation of phrenic motoneurons to increase diaphragm activation. Wild type (C57/bl6) and ChAT-Cre mice received bilateral intraspinal (C4) injections of an adeno-associated virus (AAV) encoding the hM3D(Gq) excitatory DREADD. In wild type mice, this produced non-specific DREADD expression throughout the mid-cervical ventral horn. In ChAT-Cre mice, a Cre-dependent viral construct was used to drive DREADD expression in C4 ventral horn motoneurons, targeting the phrenic motoneuron pool. Diaphragm EMG was recorded during spontaneous breathing at 6-8 weeks post-AAV delivery. The selective DREADD ligand JHU37160 (J60) caused a bilateral, sustained (>1 hr) increase in inspiratory EMG bursting in both groups; the relative increase was greater in ChAT-Cre mice. Additional experiments in a ChAT-Cre rat model were conducted to determine if spinal DREADD activation could increase inspiratory tidal volume (VT) during spontaneous breathing without anesthesia. Three to four months after intraspinal (C4) injection of AAV driving Cre-dependent hM3D(Gq) expression, intravenous J60 resulted in a sustained (>30 min) increase in VT assessed using whole-body plethysmography. Subsequently, direct nerve recordings confirmed that J60 evoked a >50% increase in inspiratory phrenic output. The data show that mid-cervical spinal DREADD expression targeting the phrenic motoneuron pool enables ligand-induced, sustained increases in the neural drive to the diaphragm. Further development of this technology may enable application to clinical conditions associated with impaired diaphragm activation and hypoventilation.
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Affiliation(s)
- Ethan S Benevides
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32601
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32601
| | - Prajwal P Thakre
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32601
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32601
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32601
| | - Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32601
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32601
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32601
| | - Michael D Sunshine
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32601
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32601
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32601
| | - Victoria N Jensen
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32601
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32601
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32601
| | - Karim Oweiss
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32601
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, 32601
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32601
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32601
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32601
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Jensen VN, Huffman EE, Jalufka FL, Pritchard AL, Baumgartner S, Walling I, C. Gibbs H, McCreedy DA, Alilain WJ, Crone SA. V2a neurons restore diaphragm function in mice following spinal cord injury. Proc Natl Acad Sci U S A 2024; 121:e2313594121. [PMID: 38442182 PMCID: PMC10945804 DOI: 10.1073/pnas.2313594121] [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: 08/07/2023] [Accepted: 01/15/2024] [Indexed: 03/07/2024] Open
Abstract
The specific roles that different types of neurons play in recovery from injury is poorly understood. Here, we show that increasing the excitability of ipsilaterally projecting, excitatory V2a neurons using designer receptors exclusively activated by designer drugs (DREADDs) restores rhythmic bursting activity to a previously paralyzed diaphragm within hours, days, or weeks following a C2 hemisection injury. Further, decreasing the excitability of V2a neurons impairs tonic diaphragm activity after injury as well as activation of inspiratory activity by chemosensory stimulation, but does not impact breathing at rest in healthy animals. By examining the patterns of muscle activity produced by modulating the excitability of V2a neurons, we provide evidence that V2a neurons supply tonic drive to phrenic circuits rather than increase rhythmic inspiratory drive at the level of the brainstem. Our results demonstrate that the V2a class of neurons contribute to recovery of respiratory function following injury. We propose that altering V2a excitability is a potential strategy to prevent respiratory motor failure and promote recovery of breathing following spinal cord injury.
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Affiliation(s)
- Victoria N. Jensen
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH45219
| | - Emily E. Huffman
- Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY40536
- Spinal Cord and Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, KY40536
| | - Frank L. Jalufka
- Department of Biology, Texas A&M University, College Station, TX77843
| | - Anna L. Pritchard
- Department of Biomedical Engineering, Texas A&M University, College Station, TX77843
| | - Sarah Baumgartner
- Division of Neurosurgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
| | - Ian Walling
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH45219
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH45267
| | - Holly C. Gibbs
- Department of Biomedical Engineering, Texas A&M University, College Station, TX77843
- Microscopy and Imaging Center, Texas A&M University, College Station, TX77843
| | - Dylan A. McCreedy
- Department of Biology, Texas A&M University, College Station, TX77843
- Department of Biomedical Engineering, Texas A&M University, College Station, TX77843
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX77843
| | - Warren J. Alilain
- Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY40536
- Spinal Cord and Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, KY40536
| | - Steven A. Crone
- Division of Neurosurgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH45267
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Chalif JI, Chavarro VS, Mensah E, Johnston B, Fields DP, Chalif EJ, Chiang M, Sutton O, Yong R, Trumbower R, Lu Y. Epidural Spinal Cord Stimulation for Spinal Cord Injury in Humans: A Systematic Review. J Clin Med 2024; 13:1090. [PMID: 38398403 PMCID: PMC10889415 DOI: 10.3390/jcm13041090] [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: 01/25/2024] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
(1) Background: Spinal cord injury (SCI) represents a major health challenge, often leading to significant and permanent sensorimotor and autonomic dysfunctions. This study reviews the evolving role of epidural spinal cord stimulation (eSCS) in treating chronic SCI, focusing on its efficacy and safety. The objective was to analyze how eSCS contributes to the recovery of neurological functions in SCI patients. (2) Methods: We utilized the PRISMA guidelines and performed a comprehensive search across MEDLINE/PubMed, Embase, Web of Science, and IEEE Xplore databases up until September 2023. We identified studies relevant to eSCS in SCI and extracted assessments of locomotor, cardiovascular, pulmonary, and genitourinary functions. (3) Results: A total of 64 studies encompassing 306 patients were identified. Studies investigated various stimulation devices, parameters, and rehabilitation methods. Results indicated significant improvements in motor function: 44% of patients achieved assisted or independent stepping or standing; 87% showed enhanced muscle activity; 65% experienced faster walking speeds; and 80% improved in overground walking. Additionally, eSCS led to better autonomic function, evidenced by improvements in bladder and sexual functions, airway pressures, and bowel movements. Notable adverse effects included device migration, infections, and post-implant autonomic dysreflexia, although these were infrequent. (4) Conclusion: Epidural spinal cord stimulation is emerging as an effective and generally safe treatment for chronic SCI, particularly when combined with intensive physical rehabilitation. Future research on standardized stimulation parameters and well-defined therapy regimens will optimize benefits for specific patient populations.
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Affiliation(s)
- J. I. Chalif
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (J.I.C.); (V.S.C.); (B.J.)
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
| | - V. S. Chavarro
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (J.I.C.); (V.S.C.); (B.J.)
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
- Department of Physical Medicine and Rehabilitation, Spaulding Hospital Cambridge, Cambridge, MA 02115, USA
| | - E. Mensah
- Chan School of Public Health, Harvard University, Boston, MA 02115, USA;
| | - B. Johnston
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (J.I.C.); (V.S.C.); (B.J.)
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
| | - D. P. Fields
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - E. J. Chalif
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (J.I.C.); (V.S.C.); (B.J.)
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
| | - M. Chiang
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
- Department of Physical Medicine and Rehabilitation, Spaulding Hospital Cambridge, Cambridge, MA 02115, USA
- Department of Anesthesiology Perioperative and Pain Management, Brigham and Women’s Hospital, Boston, MA 02115, USA;
| | - O. Sutton
- Department of Anesthesiology Perioperative and Pain Management, Brigham and Women’s Hospital, Boston, MA 02115, USA;
| | - R. Yong
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
- Department of Anesthesiology Perioperative and Pain Management, Brigham and Women’s Hospital, Boston, MA 02115, USA;
| | - R. Trumbower
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
- Department of Physical Medicine and Rehabilitation, Spaulding Hospital Cambridge, Cambridge, MA 02115, USA
| | - Y. Lu
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (J.I.C.); (V.S.C.); (B.J.)
- Harvard Medical School, Boston, MA 02115, USA; (M.C.); (R.Y.); (R.T.)
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González-García M, Carrillo-Franco L, Morales-Luque C, Dawid-Milner MS, López-González MV. Central Autonomic Mechanisms Involved in the Control of Laryngeal Activity and Vocalization. BIOLOGY 2024; 13:118. [PMID: 38392336 PMCID: PMC10886357 DOI: 10.3390/biology13020118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/07/2024] [Accepted: 02/10/2024] [Indexed: 02/24/2024]
Abstract
In humans, speech is a complex process that requires the coordinated involvement of various components of the phonatory system, which are monitored by the central nervous system. The larynx in particular plays a crucial role, as it enables the vocal folds to meet and converts the exhaled air from our lungs into audible sounds. Voice production requires precise and sustained exhalation, which generates an air pressure/flow that creates the pressure in the glottis required for voice production. Voluntary vocal production begins in the laryngeal motor cortex (LMC), a structure found in all mammals, although the specific location in the cortex varies in humans. The LMC interfaces with various structures of the central autonomic network associated with cardiorespiratory regulation to allow the perfect coordination between breathing and vocalization. The main subcortical structure involved in this relationship is the mesencephalic periaqueductal grey matter (PAG). The PAG is the perfect link to the autonomic pontomedullary structures such as the parabrachial complex (PBc), the Kölliker-Fuse nucleus (KF), the nucleus tractus solitarius (NTS), and the nucleus retroambiguus (nRA), which modulate cardiovascular autonomic function activity in the vasomotor centers and respiratory activity at the level of the generators of the laryngeal-respiratory motor patterns that are essential for vocalization. These cores of autonomic structures are not only involved in the generation and modulation of cardiorespiratory responses to various stressors but also help to shape the cardiorespiratory motor patterns that are important for vocal production. Clinical studies show increased activity in the central circuits responsible for vocalization in certain speech disorders, such as spasmodic dysphonia because of laryngeal dystonia.
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Affiliation(s)
- Marta González-García
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
| | - Laura Carrillo-Franco
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
| | - Carmen Morales-Luque
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
| | - Marc Stefan Dawid-Milner
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
| | - Manuel Víctor López-González
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
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5
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Torres R, Giovanella C, Sessums K. Type I and type IV dermoid sinus with associated cervical spina bifida in a Labrador Retriever mixed breed dog. Vet Med Sci 2024; 10:e1319. [PMID: 37965842 PMCID: PMC10789649 DOI: 10.1002/vms3.1319] [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: 12/14/2021] [Revised: 10/11/2023] [Accepted: 10/23/2023] [Indexed: 11/16/2023] Open
Abstract
A 6-month-old female Labrador Retriever mix rescued by a local shelter developed respiratory distress and later became tetraplegic. After transferring to a specialty centre, diagnostic imaging (CT and MRI) revealed spina bifida at C3 and dermoid sinuses at the level of C3 and T1. Surgery was performed to remove the dermoid sinuses. The dog was placed on broad-spectrum antibiotics and a tapering anti-inflammatory dose of prednisone, postoperatively. Independent ambulation was regained within 14 days with no recurrence of neurologic clinical signs.
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Affiliation(s)
- Roman Torres
- Department of Neurology and NeurosurgeryMississippi State University College of Veterinary MedicineMississippi StateMississippiUSA
| | - Carley Giovanella
- Department of Neurology and NeurosurgeryGulf Coast Veterinary SpecialistsHoustonTexasUSA
| | - Kara Sessums
- Department of Neurology and NeurosurgeryGulf Coast Veterinary SpecialistsHoustonTexasUSA
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6
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Krohn F, Novello M, van der Giessen RS, De Zeeuw CI, Pel JJM, Bosman LWJ. The integrated brain network that controls respiration. eLife 2023; 12:83654. [PMID: 36884287 PMCID: PMC9995121 DOI: 10.7554/elife.83654] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/29/2023] [Indexed: 03/09/2023] Open
Abstract
Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.
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Affiliation(s)
- Friedrich Krohn
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Manuele Novello
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Johan J M Pel
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
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Galer EL, Huang R, Madhavan M, Wang E, Zhou Y, Leiter JC, Lu DC. Cervical Epidural Electrical Stimulation Increases Respiratory Activity through Somatostatin-Expressing Neurons in the Dorsal Cervical Spinal Cord in Rats. J Neurosci 2023; 43:419-432. [PMID: 36639888 PMCID: PMC9864577 DOI: 10.1523/jneurosci.1958-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 09/21/2022] [Accepted: 09/29/2022] [Indexed: 12/12/2022] Open
Abstract
We tested the hypothesis that dorsal cervical epidural electrical stimulation (CEES) increases respiratory activity in male and female anesthetized rats. Respiratory frequency and minute ventilation were significantly increased when CEES was applied dorsally to the C2-C6 region of the cervical spinal cord. By injecting pseudorabies virus into the diaphragm and using c-Fos activity to identify neurons activated during CEES, we found neurons in the dorsal horn of the cervical spinal cord in which c-Fos and pseudorabies were co-localized, and these neurons expressed somatostatin (SST). Using dual viral infection to express the inhibitory Designer Receptors Exclusively Activated by Designer Drugs (DREADD), hM4D(Gi), selectively in SST-positive cells, we inhibited SST-expressing neurons by administering Clozapine N-oxide (CNO). During CNO-mediated inhibition of SST-expressing cervical spinal neurons, the respiratory excitation elicited by CEES was diminished. Thus, dorsal cervical epidural stimulation activated SST-expressing neurons in the cervical spinal cord, likely interneurons, that communicated with the respiratory pattern generating network to effect changes in ventilation.SIGNIFICANCE STATEMENT A network of pontomedullary neurons within the brainstem generates respiratory behaviors that are susceptible to modulation by a variety of inputs; spinal sensory and motor circuits modulate and adapt this output to meet the demands placed on the respiratory system. We explored dorsal cervical epidural electrical stimulation (CEES) excitation of spinal circuits to increase ventilation in rats. We identified dorsal somatostatin (SST)-expressing neurons in the cervical spinal cord that were activated (c-Fos-positive) by CEES. CEES no longer stimulated ventilation during inhibition of SST-expressing spinal neuronal activity, thereby demonstrating that spinal SST neurons participate in the activation of respiratory circuits affected by CEES. This work establishes a mechanistic foundation to repurpose a clinically accessible neuromodulatory therapy to activate respiratory circuits and stimulate ventilation.
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Affiliation(s)
- Erika L Galer
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
- Department of Molecular Cellular and Integrative Physiology, University of California Los Angeles, Los Angeles 90095, California
| | - Ruyi Huang
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - Meghna Madhavan
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - Emily Wang
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - Yan Zhou
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
| | - James C Leiter
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
- Research Service, White River Junction VA Medical Center, White River Junction 05009, Vermont
| | - Daniel C Lu
- Department of Neurosurgery, University of California Los Angeles, Los Angeles 90095, California
- Department of Molecular Cellular and Integrative Physiology, University of California Los Angeles, Los Angeles 90095, California
- Brain Research Institute, University of California Los Angeles, Los Angeles 90095, California
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Schottelkotte KM, Crone SA. Forebrain control of breathing: Anatomy and potential functions. Front Neurol 2022; 13:1041887. [PMID: 36388186 PMCID: PMC9663927 DOI: 10.3389/fneur.2022.1041887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 10/11/2022] [Indexed: 01/25/2023] Open
Abstract
The forebrain plays important roles in many critical functions, including the control of breathing. We propose that the forebrain is important for ensuring that breathing matches current and anticipated behavioral, emotional, and physiological needs. This review will summarize anatomical and functional evidence implicating forebrain regions in the control of breathing. These regions include the cerebral cortex, extended amygdala, hippocampus, hypothalamus, and thalamus. We will also point out areas where additional research is needed to better understand the specific roles of forebrain regions in the control of breathing.
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Affiliation(s)
- Karl M. Schottelkotte
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steven A. Crone
- Division of Pediatric Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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9
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Locke KC, Randelman ML, Hoh DJ, Zholudeva LV, Lane MA. Respiratory plasticity following spinal cord injury: perspectives from mouse to man. Neural Regen Res 2022; 17:2141-2148. [PMID: 35259820 PMCID: PMC9083159 DOI: 10.4103/1673-5374.335839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/18/2021] [Accepted: 10/20/2021] [Indexed: 12/03/2022] Open
Abstract
The study of respiratory plasticity in animal models spans decades. At the bench, researchers use an array of techniques aimed at harnessing the power of plasticity within the central nervous system to restore respiration following spinal cord injury. This field of research is highly clinically relevant. People living with cervical spinal cord injury at or above the level of the phrenic motoneuron pool at spinal levels C3-C5 typically have significant impairments in breathing which may require assisted ventilation. Those who are ventilator dependent are at an increased risk of ventilator-associated co-morbidities and have a drastically reduced life expectancy. Pre-clinical research examining respiratory plasticity in animal models has laid the groundwork for clinical trials. Despite how widely researched this injury is in animal models, relatively few treatments have broken through the preclinical barrier. The three goals of this present review are to define plasticity as it pertains to respiratory function post-spinal cord injury, discuss plasticity models of spinal cord injury used in research, and explore the shift from preclinical to clinical research. By investigating current targets of respiratory plasticity research, we hope to illuminate preclinical work that can influence future clinical investigations and the advancement of treatments for spinal cord injury.
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Affiliation(s)
- Katherine C. Locke
- Department of Neurobiology & Anatomy, Drexel University, Philadelphia, PA, USA
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
| | - Margo L. Randelman
- Department of Neurobiology & Anatomy, Drexel University, Philadelphia, PA, USA
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
| | - Daniel J. Hoh
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, FL, USA
| | - Lyandysha V. Zholudeva
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
- Cardiovascular Disease, Gladstone Institutes, San Francisco, CA, USA
| | - Michael A. Lane
- Department of Neurobiology & Anatomy, Drexel University, Philadelphia, PA, USA
- Marion Murray Spinal Cord Research Center, Philadelphia, PA, USA
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Kallet RH, Branson RD, Lipnick MS. Respiratory Drive, Dyspnea, and Silent Hypoxemia: A Physiological Review in the Context of COVID-19. Respir Care 2022; 67:1343-1360. [PMID: 35501129 PMCID: PMC9994317 DOI: 10.4187/respcare.10075] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Infection with SARS-CoV-2 in select individuals results in viral sepsis, pneumonia, and hypoxemic respiratory failure, collectively known as COVID-19. In the early months of the pandemic, the combination of novel disease presentation, enormous surges of critically ill patients, and severity of illness lent to early observations and pronouncements regarding COVID-19 that could not be scientifically validated owing to crisis circumstances. One of these was a phenomenon referred to as "happy hypoxia." Widely discussed in the lay press, it was thought to represent a novel and perplexing phenomenon: severe hypoxemia coupled with the absence of respiratory distress and dyspnea. Silent hypoxemia is the preferred term describing an apparent lack of distress in the presence of hypoxemia. However, the phenomenon is well known among respiratory physiologists as hypoxic ventilatory decline. Silent hypoxemia can be explained by physiologic mechanisms governing the control of breathing, breathing perception, and cardiovascular compensation. This narrative review examines silent hypoxemia during COVID-19 as well as hypotheses that viral infection of the central and peripheral nervous system may be implicated. Moreover, the credulous embrace of happy hypoxia and the novel hypotheses proposed to explain it has exposed significant misunderstandings among clinicians regarding the physiologic mechanisms governing both the control of breathing and the modulation of breathing sensations. Therefore, a substantial focus of this paper is to provide an in-depth review of these topics.
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Affiliation(s)
- Richard H Kallet
- Department of Anesthesia and Perioperative Care, University of California, San Francisco at San Francisco General Hospital, San Francisco, California.
| | - Richard D Branson
- Department of Surgery, Trauma and Critical Care Division, University of Cincinnati, Cincinnati, Ohio
| | - Michael S Lipnick
- Department of Anesthesia and Perioperative Care, University of California, San Francisco at San Francisco General Hospital, San Francisco, California
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11
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Pitts T, Iceman KE, Huff A, Musselwhite MN, Frazure ML, Young KC, Greene CL, Howland DR. Laryngeal and swallow dysregulation following acute cervical spinal cord injury. J Neurophysiol 2022; 128:405-417. [PMID: 35830612 PMCID: PMC9359645 DOI: 10.1152/jn.00469.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Laryngeal function is vital to airway protection. While swallow is mediated by the brainstem, mechanisms underlying increased risk of dysphagia after cervical spinal cord injury (SCI) are unknown. We hypothesized that loss of descending phrenic drive affects swallow and breathing differently, and loss of ascending spinal afferent information alters swallow regulation. We recorded electromyograms from upper airway and chest wall muscles in freely breathing pentobarbital-anesthetized cats and rats. Inspiratory laryngeal activity increased ~two-fold following C2 lateral-hemisection. Ipsilateral to the injury, crural diaphragm EMG amplitude was reduced during breathing (62 ± 25% change post-injury), but no animal had complete termination of activity; 75% of animals increased contralateral diaphragm recruitment, but this did not reach significance. During swallow, laryngeal adductor and pharyngeal constrictor muscles increased activity, and diaphragm activity was bilaterally suppressed. This was unexpected because of the ipsilateral-specific response during breathing. Swallow-breathing coordination was also disrupted and more swallows occurred during early expiration. Finally, to determine if the chest wall is a major source of feedback for laryngeal regulation, we performed T1 total transections in rats. As in the C2 lateral-hemisection, inspiratory laryngeal recruitment was the first feature noted. In contrast to the C2 lateral-hemisection, diaphragmatic drive increased after T1 transection. Overall, we found that SCI alters laryngeal drive during swallow and breathing, and reduced swallow-related diaphragm activity. Our results show behavior-specific effects, suggesting SCI affects swallow more than breathing, and emphasizes the need for additional studies on the effects of ascending afferents from the spinal cord on laryngeal function.
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Affiliation(s)
- Teresa Pitts
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Kimberly E Iceman
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Alyssa Huff
- Center for Integrative Brain Research, Seattle Children's Hospital, Seattle, WA, United States
| | - Matthew Nicholas Musselwhite
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Michael L Frazure
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Kellyanna C Young
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Clinton L Greene
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Dena Ruth Howland
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Research Service, Robley Rex VA Medical Center, Louisville, KY, United States
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12
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Huang R, Worrell J, Garner E, Wang S, Homsey T, Xu B, Galer EL, Zhou Y, Tavakol S, Daneshvar M, Le T, Vinters HV, Salamon N, McArthur DL, Nuwer MR, Wu I, Leiter JC, Lu DC. Epidural electrical stimulation of the cervical spinal cord opposes opioid-induced respiratory depression. J Physiol 2022; 600:2973-2999. [PMID: 35639046 DOI: 10.1113/jp282664] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/25/2022] [Indexed: 02/02/2023] Open
Abstract
Opioid overdose suppresses brainstem respiratory circuits, causes apnoea and may result in death. Epidural electrical stimulation (EES) at the cervical spinal cord facilitated motor activity in rodents and humans, and we hypothesized that EES of the cervical spinal cord could antagonize opioid-induced respiratory depression in humans. Eighteen patients requiring surgical access to the dorsal surface of the spinal cord between C2 and C7 received EES or sham stimulation for up to 90 s at 5 or 30 Hz during complete (OFF-State) or partial suppression (ON-State) of respiration induced by remifentanil. During the ON-State, 30 Hz EES at C4 and 5 Hz EES at C3/4 increased tidal volume and decreased the end-tidal carbon dioxide level compared to pre-stimulation control levels. EES of 5 Hz at C5 and C7 increased respiratory frequency compared to pre-stimulation control levels. In the OFF-State, 30 Hz cervical EES at C3/4 terminated apnoea and induced rhythmic breathing. In cadaveric tissue obtained from a brain bank, more neurons expressed both the neurokinin 1 receptor (NK1R) and somatostatin (SST) in the cervical spinal levels responsive to EES (C3/4, C6 and C7) compared to a region non-responsive to EES (C2). Thus, the capacity of cervical EES to oppose opioid depression of respiration may be mediated by NK1R+/SST+ neurons in the dorsal cervical spinal cord. This study provides proof of principle that cervical EES may provide a novel therapeutic approach to augment respiratory activity when the neural function of the central respiratory circuits is compromised by opioids or other pathological conditions. KEY POINTS: Epidural electrical stimulation (EES) using an implanted spinal cord stimulator (SCS) is an FDA-approved method to manage chronic pain. We tested the hypothesis that cervical EES facilitates respiration during administration of opioids in 18 human subjects who were treated with low-dose remifentanil that suppressed respiration (ON-State) or high-dose remifentanil that completely inhibited breathing (OFF-State) during the course of cervical surgery. Dorsal cervical EES of the spinal cord augmented the respiratory tidal volume or increased the respiratory frequency, and the response to EES varied as a function of the stimulation frequency (5 or 30 Hz) and the cervical level stimulated (C2-C7). Short, continuous cervical EES restored a cyclic breathing pattern (eupnoea) in the OFF-State, suggesting that cervical EES reversed the opioid-induced respiratory depression. These findings add to our understanding of respiratory pattern modulation and suggest a novel mechanism to oppose the respiratory depression caused by opioids.
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Affiliation(s)
- Ruyi Huang
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Interdepartmental Program in Neuroscience, University of California, Los Angeles, CA, USA
| | - Jason Worrell
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Eric Garner
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Stephanie Wang
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Tali Homsey
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Bo Xu
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Erika L Galer
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Molecular, Cellular, Integrated Physiology Program, University of California, Los Angeles, CA, USA
| | - Yan Zhou
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Sherwin Tavakol
- Department of Neurosurgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Meelod Daneshvar
- University of California Fresno, Department of Surgery, Fresno, CA, USA
| | - Timothy Le
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Harry V Vinters
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Brain Research Institute, University of California, Los Angeles, CA, USA
| | - Noriko Salamon
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - David L McArthur
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Marc R Nuwer
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Irene Wu
- Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - James C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine, Lebanon, NH, USA
| | - Daniel C Lu
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Neuromotor Recovery and Rehabilitation Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Interdepartmental Program in Neuroscience, University of California, Los Angeles, CA, USA.,Brain Research Institute, University of California, Los Angeles, CA, USA
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13
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Bajjig A, Cayetanot F, Taylor JA, Bodineau L, Vivodtzev I. Serotonin 1A Receptor Pharmacotherapy and Neuroplasticity in Spinal Cord Injury. Pharmaceuticals (Basel) 2022; 15:ph15040460. [PMID: 35455457 PMCID: PMC9025596 DOI: 10.3390/ph15040460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/01/2022] [Accepted: 04/06/2022] [Indexed: 11/30/2022] Open
Abstract
Spinal cord injury is associated with damage in descending and ascending pathways between brainstem/cortex and spinal neurons, leading to loss in sensory-motor functions. This leads not only to locomotor reduction but also to important respiratory impairments, both reducing cardiorespiratory engagement, and increasing cardiovascular risk and mortality. Moreover, individuals with high-level injuries suffer from sleep-disordered breathing in a greater proportion than the general population. Although no current treatments exist to restore motor function in spinal cord injury (SCI), serotoninergic (5-HT) 1A receptor agonists appear as pharmacologic neuromodulators that could be important players in inducing functional improvements by increasing the activation of spared motoneurons. Indeed, single therapies of serotoninergic 1A (5-HT1A) agonists allow for acute and temporary recovery of locomotor function. Moreover, the 5-HT1A agonist could be even more promising when combined with other pharmacotherapies, exercise training, and/or spinal stimulation, rather than administered alone. In this review, we discuss previous and emerging evidence showing the value of the 5HT1A receptor agonist therapies for motor and respiratory limitations in SCI. Moreover, we provide mechanistic hypotheses and clinical impact for the potential benefit of 5-HT1A agonist pharmacology in inducing neuroplasticity and improving locomotor and respiratory functions in SCI.
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Affiliation(s)
- Afaf Bajjig
- Sorbonne Université, Inserm, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; (A.B.); (F.C.); (L.B.)
| | - Florence Cayetanot
- Sorbonne Université, Inserm, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; (A.B.); (F.C.); (L.B.)
| | - J. Andrew Taylor
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, Cambridge, MA 02139, USA;
| | - Laurence Bodineau
- Sorbonne Université, Inserm, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; (A.B.); (F.C.); (L.B.)
| | - Isabelle Vivodtzev
- Sorbonne Université, Inserm, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; (A.B.); (F.C.); (L.B.)
- Correspondence:
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14
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Malone IG, Kelly MN, Nosacka RL, Nash MA, Yue S, Xue W, Otto KJ, Dale EA. Closed-Loop, Cervical, Epidural Stimulation Elicits Respiratory Neuroplasticity after Spinal Cord Injury in Freely Behaving Rats. eNeuro 2022; 9:ENEURO.0426-21.2021. [PMID: 35058311 PMCID: PMC8856702 DOI: 10.1523/eneuro.0426-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/08/2021] [Accepted: 12/24/2021] [Indexed: 11/28/2022] Open
Abstract
Over half of all spinal cord injuries (SCIs) are cervical, which can lead to paralysis and respiratory compromise, causing significant morbidity and mortality. Effective treatments to restore breathing after severe upper cervical injury are lacking; thus, it is imperative to develop therapies to address this. Epidural stimulation has successfully restored motor function after SCI for stepping, standing, reaching, grasping, and postural control. We hypothesized that closed-loop stimulation triggered via healthy hemidiaphragm EMG activity has the potential to elicit functional neuroplasticity in spinal respiratory pathways after cervical SCI (cSCI). To test this, we delivered closed-loop, electrical, epidural stimulation (CLES) at the level of the phrenic motor nucleus (C4) for 3 d after C2 hemisection (C2HS) in freely behaving rats. A 2 × 2 Latin Square experimental design incorporated two treatments, C2HS injury and CLES therapy resulting in four groups of adult, female Sprague Dawley rats: C2HS + CLES (n = 8), C2HS (n = 6), intact + CLES (n = 6), intact (n = 6). In stimulated groups, CLES was delivered for 12-20 h/d for 3 d. After C2HS, 3 d of CLES robustly facilitated the slope of stimulus-response curves of ipsilesional spinal motor evoked potentials (sMEPs) versus nonstimulated controls. To our knowledge, this is the first demonstration of CLES eliciting respiratory neuroplasticity after C2HS in freely behaving animals. These findings suggest CLES as a promising future therapy to address respiratory deficiency associated with cSCI.
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Affiliation(s)
- Ian G Malone
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL 32611
| | - Mia N Kelly
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL 32611
- Department of Physical Therapy, University of Florida, Gainesville, FL 32611
| | - Rachel L Nosacka
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32611
| | - Marissa A Nash
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32611
| | - Sijia Yue
- Department of Biostatistics, University of Florida, Gainesville, FL 32611
| | - Wei Xue
- Department of Biostatistics, University of Florida, Gainesville, FL 32611
| | - Kevin J Otto
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL 32611
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611
- Department of Neurology, University of Florida, Gainesville, FL 32611
- Department of Neuroscience, University of Florida, Gainesville, FL 32611
| | - Erica A Dale
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL 32611
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32611
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611
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15
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Deng L, Ravenscraft B, Xu XM. Exploring propriospinal neuron-mediated neural circuit plasticity using recombinant viruses after spinal cord injury. Exp Neurol 2021; 349:113962. [PMID: 34953895 DOI: 10.1016/j.expneurol.2021.113962] [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: 06/07/2021] [Revised: 12/16/2021] [Accepted: 12/19/2021] [Indexed: 11/04/2022]
Abstract
Propriospinal neurons (PSNs) play a crucial role in motor control and sensory processing and contribute to plastic reorganization of spinal circuits responsible for recovery from spinal cord injury (SCI). Due to their scattered distribution and various intersegmental projection patterns, it is challenging to dissect the function of PSNs within the neuronal network. New genetically encoded tools, particularly cell-type-specific transgene expression methods using recombinant viral vectors combined with other genetic, pharmacologic, and optogenetic approaches, have enormous potential for visualizing PSNs in the neuronal circuits and monitoring and manipulating their activity. Furthermore, recombinant viral tools have been utilized to promote the intrinsic regenerative capacities of PSNs, towards manipulating the 'hostile' microenvironment for improving functional regeneration of PSNs. Here we summarize the latest development in this fast-moving field and provide a perspective for using this technology to dissect PSN physiological role in contributing to recovery of function after SCI.
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Affiliation(s)
- Lingxiao Deng
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Baylen Ravenscraft
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, United States.
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16
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Randelman M, Zholudeva LV, Vinit S, Lane MA. Respiratory Training and Plasticity After Cervical Spinal Cord Injury. Front Cell Neurosci 2021; 15:700821. [PMID: 34621156 PMCID: PMC8490715 DOI: 10.3389/fncel.2021.700821] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/11/2021] [Indexed: 12/30/2022] Open
Abstract
While spinal cord injuries (SCIs) result in a vast array of functional deficits, many of which are life threatening, the majority of SCIs are anatomically incomplete. Spared neural pathways contribute to functional and anatomical neuroplasticity that can occur spontaneously, or can be harnessed using rehabilitative, electrophysiological, or pharmacological strategies. With a focus on respiratory networks that are affected by cervical level SCI, the present review summarizes how non-invasive respiratory treatments can be used to harness this neuroplastic potential and enhance long-term recovery. Specific attention is given to "respiratory training" strategies currently used clinically (e.g., strength training) and those being developed through pre-clinical and early clinical testing [e.g., intermittent chemical stimulation via altering inhaled oxygen (hypoxia) or carbon dioxide stimulation]. Consideration is also given to the effect of training on non-respiratory (e.g., locomotor) networks. This review highlights advances in this area of pre-clinical and translational research, with insight into future directions for enhancing plasticity and improving functional outcomes after SCI.
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Affiliation(s)
- Margo Randelman
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Lyandysha V Zholudeva
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States.,Gladstone Institutes, San Francisco, CA, United States
| | - Stéphane Vinit
- INSERM, END-ICAP, Université Paris-Saclay, UVSQ, Versailles, France
| | - Michael A Lane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
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17
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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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18
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Zholudeva LV, Abraira VE, Satkunendrarajah K, McDevitt TC, Goulding MD, Magnuson DSK, Lane MA. Spinal Interneurons as Gatekeepers to Neuroplasticity after Injury or Disease. J Neurosci 2021; 41:845-854. [PMID: 33472820 PMCID: PMC7880285 DOI: 10.1523/jneurosci.1654-20.2020] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Spinal interneurons are important facilitators and modulators of motor, sensory, and autonomic functions in the intact CNS. This heterogeneous population of neurons is now widely appreciated to be a key component of plasticity and recovery. This review highlights our current understanding of spinal interneuron heterogeneity, their contribution to control and modulation of motor and sensory functions, and how this role might change after traumatic spinal cord injury. We also offer a perspective for how treatments can optimize the contribution of interneurons to functional improvement.
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Affiliation(s)
| | - Victoria E Abraira
- Department of Cell Biology & Neuroscience, Rutgers University, The State University of New Jersey, New Jersey, 08854
| | - Kajana Satkunendrarajah
- Departments of Neurosurgery and Physiology, Medical College of Wisconsin, Wisconsin, 53226
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, 53295
| | - Todd C McDevitt
- Gladstone Institutes, San Francisco, California, 94158
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, 94143
| | | | - David S K Magnuson
- University of Louisville, Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, 40208
| | - Michael A Lane
- Department of Neurobiology and Anatomy, and the Marion Murray Spinal Cord Research Center, Drexel University, Philadelphia, Pennsylvania, 19129
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19
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Sunshine MD, Cassarà AM, Neufeld E, Grossman N, Mareci TH, Otto KJ, Boyden ES, Fuller DD. Restoration of breathing after opioid overdose and spinal cord injury using temporal interference stimulation. Commun Biol 2021; 4:107. [PMID: 33495588 PMCID: PMC7835220 DOI: 10.1038/s42003-020-01604-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 12/14/2020] [Indexed: 01/05/2023] Open
Abstract
Respiratory insufficiency is a leading cause of death due to drug overdose or neuromuscular disease. We hypothesized that a stimulation paradigm using temporal interference (TI) could restore breathing in such conditions. Following opioid overdose in rats, two high frequency (5000 Hz and 5001 Hz), low amplitude waveforms delivered via intramuscular wires in the neck immediately activated the diaphragm and restored ventilation in phase with waveform offset (1 Hz or 60 breaths/min). Following cervical spinal cord injury (SCI), TI stimulation via dorsally placed epidural electrodes uni- or bilaterally activated the diaphragm depending on current and electrode position. In silico modeling indicated that an interferential signal in the ventral spinal cord predicted the evoked response (left versus right diaphragm) and current-ratio-based steering. We conclude that TI stimulation can activate spinal motor neurons after SCI and prevent fatal apnea during drug overdose by restoring ventilation with minimally invasive electrodes.
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Affiliation(s)
- Michael D Sunshine
- Rehabilitation Science PhD Program, University of Florida, Gainesville, FL, 32611, USA
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32611, USA
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32611, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32611, USA
| | - Antonino M Cassarà
- Foundation for Research on Information Technologies in Society (IT'IS), 8004, Zurich, Switzerland
| | - Esra Neufeld
- Foundation for Research on Information Technologies in Society (IT'IS), 8004, Zurich, Switzerland
| | - Nir Grossman
- Division of Brain Sciences, Imperial College London, London, SW7 2BU, United Kingdom
- United Kingdom Dementia Research Institute, Imperial College London, London, SW7 2BU, United Kingdom
| | - Thomas H Mareci
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Kevin J Otto
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
- Department of Neurology, University of Florida, Gainesville, FL, 32611, USA
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL, 32611, USA
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Edward S Boyden
- Departments of Brain and Cognitive Sciences, Media Arts and Sciences, and Biological Engineering, McGovern and Koch Institutes, MIT, Cambridge, MA, 02139, USA
- Howard Hughes Medical Institute, Cambridge, MA, 02138, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, 32611, USA.
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, 32611, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32611, USA.
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20
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Rana S, Zhan WZ, Mantilla CB, Sieck GC. Disproportionate loss of excitatory inputs to smaller phrenic motor neurons following cervical spinal hemisection. J Physiol 2020; 598:4693-4711. [PMID: 32735344 DOI: 10.1113/jp280130] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/20/2020] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Motor units, comprising a motor neuron and the muscle fibre it innervates, are activated in an orderly fashion to provide varying amounts of force. A unilateral C2 spinal hemisection (C2SH) disrupts predominant excitatory input from medulla, causing cessation of inspiratory-related diaphragm muscle activity, whereas higher force, non-ventilatory diaphragm activity persists. In this study, we show a disproportionately larger loss of excitatory glutamatergic innervation to small phrenic motor neurons (PhMNs) following C2SH, as compared with large PhMNs ipsilateral to injury. Our data suggest that there is a dichotomy in the distribution of inspiratory-related descending excitatory glutamatergic input to small vs. large PhMNs that reflects their differential recruitment. ABSTRACT Excitatory glutamatergic input mediating inspiratory drive to phrenic motor neurons (PhMNs) emanates primarily from the ipsilateral ventrolateral medulla. Unilateral C2 hemisection (C2SH) disrupts this excitatory input, resulting in cessation of inspiratory-related diaphragm muscle (DIAm) activity. In contrast, after C2SH, higher force, non-ventilatory DIAm activity persists. Inspiratory behaviours require recruitment of only smaller PhMNs, whereas with more forceful expulsive/straining behaviours, larger PhMNs are recruited. Accordingly, we hypothesize that C2SH primarily disrupts glutamatergic synaptic inputs to smaller PhMNs, whereas glutamatergic synaptic inputs to larger PhMNs are preserved. We examined changes in glutamatergic presynaptic input onto retrogradely labelled PhMNs using immunohistochemistry for VGLUT1 and VGLUT2. We found that 7 days after C2SH there was an ∼60% reduction in glutamatergic inputs to smaller PhMNs compared with an ∼35% reduction at larger PhMNs. These results are consistent with a more pronounced impact of C2SH on inspiratory behaviours of the DIAm, and the preservation of higher force behaviours after C2SH. These results indicate that the source of glutamatergic synaptic input to PhMNs varies depending on motor neuron size and reflects different functional control - perhaps separate central pattern generator and premotor circuits. For smaller PhMNs, the central pattern generator for inspiration is located in the pre-Bötzinger complex and premotor neurons in the ventrolateral medulla, sending predominantly ipsilateral projections via the dorsolateral funiculus. C2SH disrupts this glutamatergic input. For larger PhMNs, a large proportion of excitatory inputs appear to exist below the C2 level or from contralateral regions of the brainstem and spinal cord.
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Affiliation(s)
- Sabhya Rana
- Departments of Physiology & Biomedical Engineering and
| | - Wen-Zhi Zhan
- Departments of Physiology & Biomedical Engineering and
| | - Carlos B Mantilla
- Departments of Physiology & Biomedical Engineering and.,Anaesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
| | - Gary C Sieck
- Departments of Physiology & Biomedical Engineering and.,Anaesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
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21
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Vivodtzev I, Napolitano A, Picard G, Taylor JA. Ventilatory support during whole-body row training improves oxygen uptake efficiency in patients with high-level spinal cord injury: A pilot study. Respir Med 2020; 171:106104. [PMID: 32795903 DOI: 10.1016/j.rmed.2020.106104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 10/23/2022]
Abstract
High-level spinal cord injury (SCI) is characterized by profound respiratory compromise. One consequence is a limitation of whole-body exercise-based rehabilitation, reducing its cardioprotective effect. We investigated the use of ventilatory support during training on cardiorespiratory response to exercise. Nine subjects with high-level SCI (T3-C4) were included in this double-blind sham-controlled study. All had training adaptations plateauing for more than 6 months before enrolling in the study. After performing baseline assessment, participants were randomly assigned to continue training with non-invasive ventilation (NIV: n = 6: IPAP = 20 ± 2, EPAP: 3 cmH2O) or sham (n = 3: IPAP = 5, EPAP: 3 cmH2O) for 3 months and performed again maximal exercise tests. We compared the oxygen uptake efficiency slope (OUES, the rate of increases in VO2 in relation to increasing VE) before and after training. Training with NIV increased OUES both compared to baseline (4.1 ± 1.1 vs. 3.4 ± 1.0, i.e. +20 ± 12%, p < 0.05) and Sham (p = 0.01), representing an increase in ability to uptake oxygen for a given ventilation. This result was sustained without NIV during the test, suggesting improved cardiopulmonary reserve. Best responders were the youngest whose characteristics were very similar to sham participants. In addition, NIV tended to increase weekly rowing distance by 24% (p = 0.09, versus 10% in sham). Our results are very suggestive of a positive effect of ventilatory support during whole-body exercise in high-level SCI. Training adaptations found are of great importance since this sub-population of patients have the greatest need for exercise-based cardio-protection.
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Affiliation(s)
- Isabelle Vivodtzev
- Harvard Medical School, Department of Physical Medicine and Rehabilitation, Boston, MA, USA; Spaulding Rehabilitation Hospital, Cardiovascular Research Laboratory, Cambridge, MA, USA; Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, 75013, Paris, France.
| | - Anthony Napolitano
- Harvard Medical School, Department of Physical Medicine and Rehabilitation, Boston, MA, USA; Spaulding Rehabilitation Hospital, Cardiovascular Research Laboratory, Cambridge, MA, USA
| | - Glen Picard
- Spaulding Rehabilitation Hospital, Cardiovascular Research Laboratory, Cambridge, MA, USA
| | - J Andrew Taylor
- Harvard Medical School, Department of Physical Medicine and Rehabilitation, Boston, MA, USA; Spaulding Rehabilitation Hospital, Cardiovascular Research Laboratory, Cambridge, MA, USA
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22
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Sunshine MD, Sutor TW, Fox EJ, Fuller DD. Targeted activation of spinal respiratory neural circuits. Exp Neurol 2020; 328:113256. [PMID: 32087253 DOI: 10.1016/j.expneurol.2020.113256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/31/2020] [Accepted: 02/18/2020] [Indexed: 12/30/2022]
Abstract
Spinal interneurons which discharge in phase with the respiratory cycle have been repeatedly described over the last 50 years. These spinal respiratory interneurons are part of a complex propriospinal network that is synaptically coupled with respiratory motoneurons. This article summarizes current knowledge regarding spinal respiratory interneurons and emphasizes chemical, electrical and physiological methods for activating spinal respiratory neural circuits. Collectively, the work reviewed here shows that activating spinal interneurons can have a powerful impact on spinal respiratory motor output, and can even drive rhythmic bursting in respiratory motoneuron pools under certain conditions. We propose that the primary functions of spinal respiratory neurons include 1) shaping the respiratory pattern into the final efferent motor output from the spinal respiratory nerves; 2) coordinating respiratory muscle activation across the spinal neuraxis; 3) coordinating postural, locomotor and respiratory movements, and 4) enabling plasticity of respiratory motor output in health and disease.
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Affiliation(s)
- Michael D Sunshine
- Department of Physical Therapy, University of Florida, United States of America; McKnight Brain Institute, University of Florida, United States of America; Rehabilitation Science PhD Program, University of Florida, United States of America; Center for Respiratory Research and Rehabilitation, University of Florida, United States of America
| | - Tommy W Sutor
- Department of Physical Therapy, University of Florida, United States of America; Rehabilitation Science PhD Program, University of Florida, United States of America; Center for Respiratory Research and Rehabilitation, University of Florida, United States of America
| | - Emily J Fox
- Department of Physical Therapy, University of Florida, United States of America; Center for Respiratory Research and Rehabilitation, University of Florida, United States of America; Clinical Research Center, Brooks Rehabilitation, Jacksonville, FL, United States of America
| | - David D Fuller
- Department of Physical Therapy, University of Florida, United States of America; McKnight Brain Institute, University of Florida, United States of America; Center for Respiratory Research and Rehabilitation, University of Florida, United States of America.
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