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Kalimullina T, Sachdeva R, Pawar K, Cao S, Marwaha A, Liu J, Plunet W, Squair J, West CR, Tetzlaff W, Krassioukov AV. Neuroprotective agents ineffective in mitigating autonomic dysreflexia following experimental spinal cord injury. Exp Neurol 2024; 382:114993. [PMID: 39393671 DOI: 10.1016/j.expneurol.2024.114993] [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: 08/30/2024] [Revised: 10/07/2024] [Accepted: 10/08/2024] [Indexed: 10/13/2024]
Abstract
BACKGROUND AND OBJECTIVES Loss of supraspinal cardiovascular control and secondary damage following spinal cord injury (SCI) lead to cardiovascular dysfunction, where autonomic dysreflexia (AD), triggered by stimuli below the injury, can cause uncontrolled blood pressure (BP) surges, posing severe health risks such as stroke and seizures. While anti-inflammatory neuroprotective agents have been studied for motor recovery, their impact on cardiovascular function remains under investigated. The objective was to assess the efficacy of four clinically approved neuroprotective agents in promoting cardiovascular recovery following SCI. METHODS Male Wistar rats received contusion at the third thoracic spinal segment (T3). Fluoxetine, Glyburide, Valproic acid, and Indomethacin were first administered at 1 h or 6 h post-SCI, and every 12 h for two weeks thereafter. Four weeks following SCI, hemodynamics were measured at rest and during colorectal distension. Locomotor function was assessed prior to SCI and weekly for four weeks after SCI, using the Basso-Beattie-Bresnahan (BBB) locomotor scale. Quantitative comparisons of lesion area were performed. RESULTS Contrary to the published literature, Indomethacin and Valproic acid resulted in high morbidity and mortality rates 60 % and 40 % respectively) within 2-3 days of administration. Fluoxetine, and Glyburide were well-tolerated. There were no differences in change in systolic BP with colorectal distension compared to control i.e., all experimental groups experienced severe episodes of AD [F(6, 67) = 0.94, p = 0.47]. There was no significant difference in BBB scores in any experimental group compared to control [F(18, 252) = 0.3, p = 0.99]. No between-group differences were observed in tissue sparing at the lesion epicentre [F(6, 422) = 6.98, p = 0.29]. DISCUSSION Despite promising beneficial effect reported in previous studies, none of the drugs demonstrated improvement in cardiovascular or motor function. Indomethacin and Valproic acid exhibited unexpected high mortality at doses deemed safe in the literature. This emphasizes the necessity for reproducibility studies in pre-clinical research and underscores the importance of publishing null findings to guide future investigations.
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Affiliation(s)
- Tamila Kalimullina
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Rahul Sachdeva
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada.
| | - Kiran Pawar
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Steven Cao
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
| | - Arshdeep Marwaha
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Ward Plunet
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
| | - Jordan Squair
- Department of Neurosurgery, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Christopher R West
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Cell & Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada; GF Strong Rehabilitation Centre, Vancouver Coastal Health, Vancouver, Canada.
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Trueblood CT, Singh A, Cusimano MA, Hou S. Autonomic Dysreflexia in Spinal Cord Injury: Mechanisms and Prospective Therapeutic Targets. Neuroscientist 2024; 30:597-611. [PMID: 38084412 PMCID: PMC11166887 DOI: 10.1177/10738584231217455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
High-level spinal cord injury (SCI) often results in cardiovascular dysfunction, especially the development of autonomic dysreflexia. This disorder, characterized as an episode of hypertension accompanied by bradycardia in response to visceral or somatic stimuli, causes substantial discomfort and potentially life-threatening symptoms. The neural mechanisms underlying this dysautonomia include a loss of supraspinal control to spinal sympathetic neurons, maladaptive plasticity of sensory inputs and propriospinal interneurons, and excessive discharge of sympathetic preganglionic neurons. While neural control of cardiovascular function is largely disrupted after SCI, the renin-angiotensin system (RAS), which mediates blood pressure through hormonal mechanisms, is up-regulated after injury. Whether the RAS engages in autonomic dysreflexia, however, is still controversial. Regarding therapeutics, transplantation of embryonic presympathetic neurons, collected from the brainstem or more specific raphe regions, into the injured spinal cord may reestablish supraspinal regulation of sympathetic activity for cardiovascular improvement. This treatment reduces the occurrence of spontaneous autonomic dysreflexia and the severity of artificially triggered dysreflexic responses in rodent SCI models. Though transplanting early-stage neurons improves neural regulation of blood pressure, hormonal regulation remains high and baroreflex dysfunction persists. Therefore, cell transplantation combined with selected RAS inhibition may enhance neuroendocrine homeostasis for cardiovascular recovery after SCI.
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Affiliation(s)
- Cameron T. Trueblood
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Anurag Singh
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Marissa A. Cusimano
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Shaoping Hou
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
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Garcia-Ramirez DL, McGrath JR, Ha NT, Wheel JH, Atoche SJ, Yao L, Stachowski NJ, Giszter SF, Dougherty KJ. Covert actions of epidural stimulation on spinal locomotor circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.18.599598. [PMID: 38948733 PMCID: PMC11213016 DOI: 10.1101/2024.06.18.599598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Spinal circuitry produces the rhythm and patterning of locomotion. However, both descending and sensory inputs are required to initiate and adapt locomotion to the environment. Spinal cord injury (SCI) disrupts descending controls of the spinal cord, producing paralysis. Epidural stimulation (ES) is a promising clinical therapy for motor control recovery and is capable of reactivating the lumbar spinal locomotor networks, yet little is known about the effects of ES on locomotor neurons. Previously, we found that both sensory afferent pathways and serotonin exert mixed excitatory and inhibitory actions on lumbar interneurons involved in the generation of the locomotor rhythm, identified by the transcription factor Shox2. However, after chronic complete SCI, sensory afferent inputs to Shox2 interneurons become almost exclusively excitatory and Shox2 interneurons are supersensitive to serotonin. Here, we investigated the effects of ES on these SCI-induced changes. Inhibitory input from sensory pathways to Shox2 interneurons was maintained and serotonin supersensitivity was not observed in SCI mice that received daily sub-motor threshold ES. Interestingly, the effects of ES were maintained for at least three weeks after the ES was discontinued. In contrast, the effects of ES were not observed in Shox2 interneurons from mice that received ES after the establishment of the SCI-induced changes. Our results demonstrate mechanistic actions of ES at the level of identified spinal locomotor circuit neurons and the effectiveness of early treatment with ES on preservation of spinal locomotor circuitry after SCI, suggesting possible therapeutic benefits prior to the onset of motor rehabilitation.
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Brennan FH, Swarts EA, Kigerl KA, Mifflin KA, Guan Z, Noble BT, Wang Y, Witcher KG, Godbout JP, Popovich PG. Microglia promote maladaptive plasticity in autonomic circuitry after spinal cord injury in mice. Sci Transl Med 2024; 16:eadi3259. [PMID: 38865485 DOI: 10.1126/scitranslmed.adi3259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 05/16/2024] [Indexed: 06/14/2024]
Abstract
Robust structural remodeling and synaptic plasticity occurs within spinal autonomic circuitry after severe high-level spinal cord injury (SCI). As a result, normally innocuous visceral or somatic stimuli elicit uncontrolled activation of spinal sympathetic reflexes that contribute to systemic disease and organ-specific pathology. How hyperexcitable sympathetic circuitry forms is unknown, but local cues from neighboring glia likely help mold these maladaptive neuronal networks. Here, we used a mouse model of SCI to show that microglia surrounded active glutamatergic interneurons and subsequently coordinated multi-segmental excitatory synaptogenesis and expansion of sympathetic networks that control immune, neuroendocrine, and cardiovascular functions. Depleting microglia during critical periods of circuit remodeling after SCI prevented maladaptive synaptic and structural plasticity in autonomic networks, decreased the frequency and severity of autonomic dysreflexia, and prevented SCI-induced immunosuppression. Forced turnover of microglia in microglia-depleted mice restored structural and functional indices of pathological dysautonomia, providing further evidence that microglia are key effectors of autonomic plasticity. Additional data show that microglia-dependent autonomic plasticity required expression of triggering receptor expressed on myeloid cells 2 (Trem2) and α2δ-1-dependent synaptogenesis. These data suggest that microglia are primary effectors of autonomic neuroplasticity and dysautonomia after SCI in mice. Manipulating microglia may be a strategy to limit autonomic complications after SCI or other forms of neurologic disease.
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Affiliation(s)
- Faith H Brennan
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Department of Biomedical and Molecular Sciences and Center for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Emily A Swarts
- Department of Biomedical and Molecular Sciences and Center for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Kristina A Kigerl
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Katherine A Mifflin
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Zhen Guan
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Benjamin T Noble
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Yan Wang
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Kristina G Witcher
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Institute for Behavioral Medicine Research, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Jonathan P Godbout
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Institute for Behavioral Medicine Research, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Phillip G Popovich
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Belford Center for Spinal Cord Injury, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Institute for Behavioral Medicine Research, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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Samejima S, Shackleton C, Miller T, Moritz CT, Kessler TM, Krogh K, Sachdeva R, Krassioukov AV. Mapping the Iceberg of Autonomic Recovery: Mechanistic Underpinnings of Neuromodulation following Spinal Cord Injury. Neuroscientist 2024; 30:378-389. [PMID: 36631741 PMCID: PMC11107126 DOI: 10.1177/10738584221145570] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Spinal cord injury leads to disruption in autonomic control resulting in cardiovascular, bowel, and lower urinary tract dysfunctions, all of which significantly reduce health-related quality of life. Although spinal cord stimulation shows promise for promoting autonomic recovery, the underlying mechanisms are unclear. Based on current preclinical and clinical evidence, this narrative review provides the most plausible mechanisms underlying the effects of spinal cord stimulation for autonomic recovery, including activation of the somatoautonomic reflex and induction of neuroplastic changes in the spinal cord. Areas where evidence is limited are highlighted in an effort to guide the scientific community to further explore these mechanisms and advance the clinical translation of spinal cord stimulation for autonomic recovery.
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Affiliation(s)
- Soshi Samejima
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Claire Shackleton
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Tiev Miller
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Chet T. Moritz
- Departments of Electrical and Computer Engineering, Rehabilitation Medicine, and Physiology and Biophysics and the Center for Neurotechnology, University of Washington, Seattle, WA, USA
| | - Thomas M. Kessler
- Department of Neuro-urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Klaus Krogh
- Department of Clinical Medicine and Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Rahul Sachdeva
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Andrei V. Krassioukov
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada
- Spinal Cord Program, GF Strong Rehabilitation Centre, Vancouver Coastal Health, Vancouver, Canada
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Higano JD, Burns K, Smith G, Solinsky R. Why do different people with Spinal Cord Injury have differing severity of symptoms with Autonomic Dysreflexia? Exploring relationships of vascular alpha-1 adrenoreceptor and baroreflex sensitivity after SCI. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.02.24306772. [PMID: 38746296 PMCID: PMC11092739 DOI: 10.1101/2024.05.02.24306772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Introduction Individuals with spinal cord injury (SCI) commonly have autonomic dysreflexia (AD) with increased sympathetic activity. After SCI, individuals have decreased baroreflex sensitivity and increased vascular responsiveness. Objective To evalate relationship between baroreflex and blood vessel sensitivity with autonomic dysreflexia symptoms. Design Case control. Setting Tertiary academic center. Patients 14 individuals with SCI, 17 matched uninjured controls. Interventions All participants quantified AD symptoms using the Autonomic Dysfunction Following SCI (ADFSCI)-AD survey. Participants received three intravenous phenylephrine boluses, reproducibly increasing systolic blood pressure (SBP) 15-40 mmHg. Continuous heart rate (R-R interval, ECG), beat-to-beat blood pressures (finapres), and popliteal artery flow velocity were recorded. Vascular responsiveness (α1 adrenoreceptor sensitivity) and heart rate responsiveness to increased SBP (baroreflex sensitivity) were calculated. Main outcome measures Baroreflex sensitivity after increased SBP; Vascular responsiveness through quantified mean arterial pressure (MAP) 2-minute area under the curve and change in vascular resistance. Results SCI and control cohorts were well-matched with mean age 31.9 and 29.6 years (p=0.41), 21.4% and 17.6% female respectively. Baseline MAP (p=0.83) and R-R interval (p=0.39) were similar. ADFSCI-AD scores were higher following SCI (27.9+/-22.9 vs 4.2+/-2.9 in controls, p=0.002).To quantify SBP response, MAP area under the curve was normalized to dose/bodyweight. Individuals with SCI had significantly larger responses (0.26+/-0.19 mmHg*s/kg*ug) than controls (0.06+/-0.06 mmHg*s/kg*ug, p=0.002). Similarly, leg vascular resistance increased after SCI (24% vs 6% to a normalized dose, p=0.007). Baroreflex sensitivity was significantly lower after SCI (15.0+/-8.3 vs 23.7+/-9.3 ms/mmHg, p=0.01). ADFSCI-AD subscore had no meaningful correlation with vascular responsiveness (R2=0.008) or baroreflex sensitivity (R2=0.092) after SCI. Conclusions While this confirms smaller previous studies suggesting increased α1 adrenoreceptor sensitivity and lower baroreflex sensitivity in individuals with SCI, these differences lacked correlation to increased symptoms of AD. Further research into physiologic mechanisms to explain why some individuals with SCI develop symptoms is needed.
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Mari S, Lecomte CG, Merlet AN, Audet J, Yassine S, Eddaoui O, Genois G, Nadeau C, Harnie J, Rybak IA, Prilutsky BI, Frigon A. Changes in intra- and interlimb reflexes from hindlimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats. J Physiol 2024; 602:1987-2017. [PMID: 38593215 PMCID: PMC11068482 DOI: 10.1113/jp286151] [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: 12/15/2023] [Accepted: 03/04/2024] [Indexed: 04/11/2024] Open
Abstract
When the foot dorsum contacts an obstacle during locomotion, cutaneous afferents signal central circuits to coordinate muscle activity in the four limbs. Spinal cord injury disrupts these interactions, impairing balance and interlimb coordination. We evoked cutaneous reflexes by electrically stimulating left and right superficial peroneal nerves before and after two thoracic lateral hemisections placed on opposite sides of the cord at 9- to 13-week interval in seven adult cats (4 males and 3 females). We recorded reflex responses in ten hindlimb and five forelimb muscles bilaterally. After the first (right T5-T6) and second (left T10-T11) hemisections, coordination of the fore- and hindlimbs was altered and/or became less consistent. After the second hemisection, cats required balance assistance to perform quadrupedal locomotion. Short-latency reflex responses in homonymous and crossed hindlimb muscles largely remained unaffected after staggered hemisections. However, mid- and long-latency homonymous and crossed responses in both hindlimbs occurred less frequently after staggered hemisections. In forelimb muscles, homolateral and diagonal mid- and long-latency response occurrence significantly decreased after the first and second hemisections. In all four limbs, however, when present, short-, mid- and long-latency responses maintained their phase-dependent modulation. We also observed reduced durations of short-latency inhibitory homonymous responses in left hindlimb extensors early after the first hemisection and delayed short-latency responses in the right ipsilesional hindlimb after the first hemisection. Therefore, changes in cutaneous reflex responses correlated with impaired balance/stability and interlimb coordination during locomotion after spinal cord injury. Restoring reflex transmission could be used as a biomarker to facilitate locomotor recovery. KEY POINTS: Cutaneous afferent inputs coordinate muscle activity in the four limbs during locomotion when the foot dorsum contacts an obstacle. Thoracic spinal cord injury disrupts communication between spinal locomotor centres located at cervical and lumbar levels, impairing balance and limb coordination. We investigated cutaneous reflexes during quadrupedal locomotion by electrically stimulating the superficial peroneal nerve bilaterally, before and after staggered lateral thoracic hemisections of the spinal cord in cats. We showed a loss/reduction of mid- and long-latency responses in all four limbs after staggered hemisections, which correlated with altered coordination of the fore- and hindlimbs and impaired balance. Targeting cutaneous reflex pathways projecting to the four limbs could help develop therapeutic approaches aimed at restoring transmission in ascending and descending spinal pathways.
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Affiliation(s)
- Stephen Mari
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Charly G. Lecomte
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Angèle N. Merlet
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Johannie Audet
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Sirine Yassine
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Oussama Eddaoui
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Gabriel Genois
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Charlène Nadeau
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Jonathan Harnie
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Ilya A. Rybak
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Boris I. Prilutsky
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Alain Frigon
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
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Kerzonkuf M, Verneuil J, Brocard C, Dingu N, Trouplin V, Ramirez Franco JJ, Bartoli M, Brocard F, Bras H. Knockdown of calpain1 in lumbar motoneurons reduces spasticity after spinal cord injury in adult rats. Mol Ther 2024; 32:1096-1109. [PMID: 38291756 PMCID: PMC11163198 DOI: 10.1016/j.ymthe.2024.01.029] [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: 04/20/2023] [Revised: 12/23/2023] [Accepted: 01/23/2024] [Indexed: 02/01/2024] Open
Abstract
Spasticity, affecting ∼75% of patients with spinal cord injury (SCI), leads to hyperreflexia, muscle spasms, and cocontractions of antagonist muscles, greatly affecting their quality of life. Spasticity primarily stems from the hyperexcitability of motoneurons below the lesion, driven by an upregulation of the persistent sodium current and a downregulation of chloride extrusion. This imbalance results from the post-SCI activation of calpain1, which cleaves Nav1.6 channels and KCC2 cotransporters. Our study was focused on mitigating spasticity by specifically targeting calpain1 in spinal motoneurons. We successfully transduced lumbar motoneurons in adult rats with SCI using intrathecal administration of adeno-associated virus vector serotype 6, carrying a shRNA sequence against calpain1. This approach significantly reduced calpain1 expression in transduced motoneurons, leading to a noticeable decrease in spasticity symptoms, including hyperreflexia, muscle spasms, and cocontractions in hindlimb muscles, which are particularly evident in the second month post-SCI. In addition, this decrease, which prevented the escalation of spasticity to a severe grade, paralleled the restoration of KCC2 levels in transduced motoneurons, suggesting a reduced proteolytic activity of calpain1. These findings demonstrate that inhibiting calpain1 in motoneurons is a promising strategy for alleviating spasticity in SCI patients.
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Affiliation(s)
- Marjorie Kerzonkuf
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Jérémy Verneuil
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Cécile Brocard
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Nejada Dingu
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Virginie Trouplin
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Jose Jorge Ramirez Franco
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France
| | - Marc Bartoli
- Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université and INSERM, Marseille, France
| | - Frédéric Brocard
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France.
| | - Hélène Bras
- Institut des Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille, France.
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Brown BL, Anil N, States G, Whittemore SR, Magnuson DSK. Long ascending propriospinal neurons are heterogenous and subject to spinal cord injury induced anatomic plasticity. Exp Neurol 2024; 373:114631. [PMID: 38070723 PMCID: PMC10922963 DOI: 10.1016/j.expneurol.2023.114631] [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: 09/08/2023] [Revised: 11/15/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
Long ascending propriospinal neurons (LAPNs) are a subset of spinal interneurons that provide direct connectivity between distant spinal segments. Here, we focus specifically on an anatomically defined population of "inter-enlargement" LAPNs with cell bodies at L2/3 and terminals at C5/6. Previous studies showed that silencing LAPNs in awake and freely moving animals disrupted interlimb coordination of the hindlimbs, forelimbs, and heterolateral limb pairs. Surprisingly, despite a proportion of LAPNs being anatomically intact post- spinal cord injury (SCI), silencing them improved locomotor function but only influenced coordination of the hindlimb pair. Given the functional significance of LAPNs pre- and post-SCI, we characterized their anatomy and SCI-induced anatomical plasticity. This detailed anatomical characterization revealed three morphologically distinct subsets of LAPNs that differ in soma size, neurite complexity and/or neurite orientation. Following a mild thoracic contusive SCI there was a marked shift in neurite orientation in two of the LAPN subsets to a more dorsoventral orientation, and collateral densities decreased in the cervical enlargement but increased just caudal to the injury epicenter. These post-SCI anatomical changes potentially reflect maladaptive plasticity and an effort to establish new functional inputs from sensory afferents that sprout post-SCI to achieve circuitry homeostasis.
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Affiliation(s)
- Brandon L Brown
- Interdisciplinary Program in Translational Neuroscience, University of Louisville, Louisville, KY, United States; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Neha Anil
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Bioengineering, J.B. Speed School of Engineering, University of Louisville, Louisville, KY, United States
| | - Gregory States
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Scott R Whittemore
- Interdisciplinary Program in Translational Neuroscience, University of Louisville, Louisville, KY, United States; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States; Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States
| | - David S K Magnuson
- Interdisciplinary Program in Translational Neuroscience, University of Louisville, Louisville, KY, United States; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States; Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, United States; Department of Bioengineering, J.B. Speed School of Engineering, University of Louisville, Louisville, KY, United States; Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States.
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10
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Zhao S, Tang C, Weinberger J, Gao D, Hou S. Sprouting of afferent and efferent inputs to pelvic organs after spinal cord injury. J Neuropathol Exp Neurol 2023; 83:20-29. [PMID: 38102789 PMCID: PMC10746698 DOI: 10.1093/jnen/nlad108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Neural plasticity occurs within the central and peripheral nervous systems after spinal cord injury (SCI). Although central alterations have extensively been studied, it is largely unknown whether afferent and efferent fibers in pelvic viscera undergo similar morphological changes. Using a rat spinal cord transection model, we conducted immunohistochemistry to investigate afferent and efferent innervations to the kidney, colon, and bladder. Approximately 3-4 weeks after injury, immunostaining demonstrated that tyrosine hydroxylase (TH)-labeled postganglionic sympathetic fibers and calcitonin gene-related peptide (CGRP)-immunoreactive sensory terminals sprout in the renal pelvis and colon. Morphologically, sprouted afferent or efferent projections showed a disorganized structure. In the bladder, however, denser CGRP-positive primary sensory fibers emerged in rats with SCI, whereas TH-positive sympathetic efferent fibers did not change. Numerous CGRP-positive afferents were observed in the muscle layer and the lamina propria of the bladder following SCI. TH-positive efferent inputs displayed hypertrophy with large diameters, but their innervation patterns were sustained. Collectively, afferent or efferent inputs sprout widely in the pelvic organs after SCI, which may be one of the morphological bases underlying functional adaptation or maladaptation.
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Affiliation(s)
- Shunyi Zhao
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, USA
- Department of Pharmacology and Physiology, Drexel University College of Medicine, USA
| | - Chuanxi Tang
- Department of Neurobiology and Cell Biology, Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jeremy Weinberger
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, USA
| | - Dianshuai Gao
- Department of Neurobiology and Cell Biology, Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Shaoping Hou
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, USA
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11
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Mari S, Lecomte CG, Merlet AN, Audet J, Yassine S, Eddaoui O, Genois G, Nadeau C, Harnie J, Rybak IA, Prilutsky BI, Frigon A. Changes in intra- and interlimb reflexes from hindlimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571869. [PMID: 38168183 PMCID: PMC10760189 DOI: 10.1101/2023.12.15.571869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
When the foot dorsum contacts an obstacle during locomotion, cutaneous afferents signal central circuits to coordinate muscle activity in the four limbs. Spinal cord injury disrupts these interactions, impairing balance and interlimb coordination. We evoked cutaneous reflexes by electrically stimulating left and right superficial peroneal nerves before and after two thoracic lateral hemisections placed on opposite sides of the cord at 9-13 weeks interval in seven adult cats (4 males and 3 females). We recorded reflex responses in ten hindlimb and five forelimb muscles bilaterally. After the first (right T5-T6) and second (left T10-T11) hemisections, coordination of the fore- and hindlimbs was altered and/or became less consistent. After the second hemisection, cats required balance assistance to perform quadrupedal locomotion. Short-latency reflex responses in homonymous and crossed hindlimb muscles largely remained unaffected after staggered hemisections. However, mid- and long-latency homonymous and crossed responses in both hindlimbs occurred less frequently after staggered hemisections. In forelimb muscles, homolateral and diagonal mid- and long-latency response occurrence significantly decreased after the first and second hemisections. In all four limbs, however, when present, short-, mid- and long-latency responses maintained their phase-dependent modulation. We also observed reduced durations of short-latency inhibitory homonymous responses in left hindlimb extensors early after the first hemisection and delayed short-latency responses in the right ipsilesional hindlimb after the first hemisection. Therefore, changes in cutaneous reflex responses correlated with impaired balance/stability and interlimb coordination during locomotion after spinal cord injury. Restoring reflex transmission could be used as a biomarker to facilitate locomotor recovery.
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Affiliation(s)
- Stephen Mari
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Charly G. Lecomte
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Angèle N. Merlet
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Johannie Audet
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Sirine Yassine
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Oussama Eddaoui
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Gabriel Genois
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Charlène Nadeau
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Jonathan Harnie
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Ilya A. Rybak
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Boris I. Prilutsky
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Alain Frigon
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
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12
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Gouveia D, Carvalho C, Vong N, Pereira A, Cardoso A, Moisés M, Rijo I, Almeida A, Gamboa Ó, Ferreira A, Martins Â. Spinal shock in severe SCI dogs and early implementation of intensive neurorehabilitation programs. Res Vet Sci 2023; 164:105018. [PMID: 37722219 DOI: 10.1016/j.rvsc.2023.105018] [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: 08/27/2023] [Accepted: 09/07/2023] [Indexed: 09/20/2023]
Abstract
Spinal shock is complex, paradoxical with sudden presentation, possibly leading to a guarded prognosis. Thus, it is suggested the need for early implementation of intensive neurorehabilitation. This prospective controlled blinded cohort study aims to understand the implication of spinal shock in neurorehabilitation of severe SCI dogs and the importance of its evaluation thought a spinal shock scale (SSS). 371 dogs were randomized by stratification according the presence of spinal shock in the SG (n = 245) or CG (n = 126). The SSS, a punctuation scale (0-7), was evaluated at admission and each 6 h for 3 days, each day for 15 days, each week for 6 weeks, each month until 3 months, followed by 3 monthly follow-ups. All dogs had similar land and underwater treadmill training with functional electrical stimulation. Observational dataset allowed an approximate level of power (1-β) of 0.90 and an α (Type I error) of 0.01, with a total of 11,088 SSS observations between two blinded observers and 18% of disagreement. 75% of the dogs were admitted in 24-48 h after injury, allowing early detection of spinal shock, and dogs admitted at 72 h with SSS ≥ 4 were not able to achieve ambulation. Regarding ambulation rate, there was a significant difference between groups, with 66.9% of ambulation in the SG and 97.6% in the CG. Also, there was a difference in regard to time until ambulation, with a mean of 31.57 days for the SG and 23.02 for the CG. The SSS estimated marginal means had an exponential decrease within the first 6 h, followed by a slower decrease, but always faster in spinal shock dogs diagnosed with non-compressive myelopathies. Thus, early intensive neurorehabilitation in dogs after severe SCI may benefit from SSS classifications at admission and during treatment to establish different therapeutic protocols according to each patient's needs, especially in deep pain negative dogs.
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Affiliation(s)
- Débora Gouveia
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal; Superior School of Health, Protection and Animal Welfare, Polytechnic Institute of Lusophony, Campo Grande, Lisboa 1950-396, Portugal; Faculty of Veterinary Medicine, Lusófona University, Campo Grande, Lisboa 1749-024, Portugal
| | - Carla Carvalho
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal
| | - Natalina Vong
- Faculty of Veterinary Medicine, Évora University, Évora 94, 7002-554, Portugal
| | - Ana Pereira
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal
| | - Ana Cardoso
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal
| | - Marina Moisés
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal
| | - Inês Rijo
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal
| | - António Almeida
- Faculty of Veterinary Medicine, University of Lisbon, Lisboa 1300-477, Portugal
| | - Óscar Gamboa
- Faculty of Veterinary Medicine, University of Lisbon, Lisboa 1300-477, Portugal
| | - António Ferreira
- Faculty of Veterinary Medicine, University of Lisbon, Lisboa 1300-477, Portugal; CIISA - Centro Interdisciplinar-Investigação em Saúde Animal, Faculdade de Medicina Veterinária, Av. Universidade Técnica de Lisboa, Lisboa 1300-477, Portugal
| | - Ângela Martins
- Arrábida Veterinary Hospital - Arrábida Animal Rehabilitation Center, Setubal 2925-538, Portugal; Superior School of Health, Protection and Animal Welfare, Polytechnic Institute of Lusophony, Campo Grande, Lisboa 1950-396, Portugal; Faculty of Veterinary Medicine, Lusófona University, Campo Grande, Lisboa 1749-024, Portugal.
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13
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Solinsky R, Taylor JA. Commentary: Spinal Cord Stimulation to Improve Autonomic Regulation After Spinal Cord Injury: Can Reflex Control Be Restored. Top Spinal Cord Inj Rehabil 2023; 29:31-33. [PMID: 37235193 PMCID: PMC10208254 DOI: 10.46292/sci22-00048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Ryan Solinsky
- Cardiovascular Research Lab, Spaulding Rehabilitation Hospital, Cambridge, Massachusetts
- Spaulding Research Institute, Boston, Massachusetts
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, Massachusetts
| | - J. Andrew Taylor
- Cardiovascular Research Lab, Spaulding Rehabilitation Hospital, Cambridge, Massachusetts
- Spaulding Research Institute, Boston, Massachusetts
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, Massachusetts
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14
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Samejima S, Shackleton C, Malik RN, Cao K, Bohorquez A, Nightingale TE, Sachdeva R, Krassioukov AV. Spinal Cord Stimulation Prevents Autonomic Dysreflexia in Individuals with Spinal Cord Injury: A Case Series. J Clin Med 2023; 12:jcm12082897. [PMID: 37109234 PMCID: PMC10146034 DOI: 10.3390/jcm12082897] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/04/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Spinal cord injury (SCI) results in severe cardiovascular dysfunction due to the disruption of supraspinal control. Autonomic dysreflexia (AD), an uncontrolled rise in blood pressure in response to peripheral stimuli including common bowel routine, digital anorectal stimulation (DARS), reduces the quality of life, and increases morbidity and mortality. Recently, spinal cord stimulation (SCS) has emerged as a potential intervention to mitigate unstable blood pressure following SCI. The objective of this case series was to test the real-time effect of epidural SCS (eSCS) at the lumbosacral spinal cord, the most common implant location, on mitigating AD in individuals with SCI. We recruited three individuals with cervical and upper thoracic motor-complete SCI who have an implanted epidural stimulator. We demonstrated that eSCS can reduce the elevation in blood pressure and prevent DARS-induced AD. The blood pressure variability analysis indicated that eSCS potentially reduced vascular sympathetic nervous system activity during DARS, compared to without eSCS. This case series provides evidence to support the use of eSCS to prevent AD episodes during routine bowel procedures, improving the quality of life for individuals with SCI and potentially reducing cardiovascular risks.
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Affiliation(s)
- Soshi Samejima
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
| | - Claire Shackleton
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
| | - Raza N Malik
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
| | - Kawami Cao
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
| | - Anibal Bohorquez
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
- Spinal Cord Program, GF Strong Rehabilitation Centre, Vancouver Coastal Health, Vancouver, BC V5Z 2G9, Canada
| | - Tom E Nightingale
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Centre for Trauma Sciences Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Rahul Sachdeva
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 2G9, Canada
- Spinal Cord Program, GF Strong Rehabilitation Centre, Vancouver Coastal Health, Vancouver, BC V5Z 2G9, Canada
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15
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Wulf MJ, Tom VJ. Consequences of spinal cord injury on the sympathetic nervous system. Front Cell Neurosci 2023; 17:999253. [PMID: 36925966 PMCID: PMC10011113 DOI: 10.3389/fncel.2023.999253] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 02/09/2023] [Indexed: 03/06/2023] Open
Abstract
Spinal cord injury (SCI) damages multiple structures at the lesion site, including ascending, descending, and propriospinal axons; interrupting the conduction of information up and down the spinal cord. Additionally, axons associated with the autonomic nervous system that control involuntary physiological functions course through the spinal cord. Moreover, sympathetic, and parasympathetic preganglionic neurons reside in the spinal cord. Thus, depending on the level of an SCI, autonomic function can be greatly impacted by the trauma resulting in dysfunction of various organs. For example, SCI can lead to dysregulation of a variety of organs, such as the pineal gland, the heart and vasculature, lungs, spleen, kidneys, and bladder. Indeed, it is becoming more apparent that many disorders that negatively affect quality-of-life for SCI individuals have a basis in dysregulation of the sympathetic nervous system. Here, we will review how SCI impacts the sympathetic nervous system and how that negatively impacts target organs that receive sympathetic innervation. A deeper understanding of this may offer potential therapeutic insight into how to improve health and quality-of-life for those living with SCI.
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Affiliation(s)
| | - Veronica J. Tom
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
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16
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Struyf P, Triccas LT, Schillebeeckx F, Struyf F. The Place of Botulinum Toxin in Spastic Hemiplegic Shoulder Pain after Stroke: A Scoping Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:2797. [PMID: 36833493 PMCID: PMC9957016 DOI: 10.3390/ijerph20042797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 01/19/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Stroke is a common pathology worldwide, with an age-standardized global rate of new strokes of 150.5 per 100,000 population in 2017. Stroke causes upper motor neuron impairment leading to a spectrum of muscle weakness around the shoulder joint, changes in muscle tone, and subsequent soft tissue changes. Hemiplegic shoulder pain (HSP) is the most common pain condition in stroke patients and one of the four most common medical complications after stroke. The importance of the appropriate positioning and handling of the hemiplegic shoulder for prevention of HSP is therefore of high clinical relevance. Nevertheless, HSP remains a frequent and disabling problem after stroke, with a 1-year prevalence rate up to 39%. Furthermore, the severity of the motor impairment is one of the most important identified risk factors for HSP in literature. Spasticity is one of these motor impairments that is likely to be modifiable. After ruling out or treating other shoulder pathologies, spasticity must be assessed and treated because it could lead to a cascade of unwanted complications, including spastic HSP. In clinical practice, Botulinum toxin A (BTA) is regarded as the first-choice treatment of focal spasticity in the upper limb, as it gives the opportunity to target specifically selected muscles. It thereby provides the possibility of a unique patient tailored focal and reversible treatment for post stroke spasticity. This scoping review aims to summarize the current evidence of BTA treatment for spastic HSP. First, the clinical manifestation and outcome measures of spastic HSP will be addressed, and second the current evidence of BTA treatment of spastic HSP will be reviewed. We also go in-depth into the elements of BTA application that may optimize the therapeutic effect of BTA. Finally, future considerations for the use of BTA for spastic HSP in clinical practice and research settings will be discussed.
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Affiliation(s)
- Pieter Struyf
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, B-2610 Wilrijk, Belgium
- Department of Rehabilitation Medicine, Research School Caphri, Maastricht University Medical Center, 6200 MD Maastricht, The Netherlands
- Adelante Zorggroep, 6229 HX Maastricht, The Netherlands
| | - Lisa Tedesco Triccas
- REVAL, Faculty of Rehabilitation Sciences, Universiteit Hasselt, B-3590 Diepenbeek, Belgium
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Fabienne Schillebeeckx
- Department of Physical Medicine and Rehabilitation, University Hospital Leuven, B-3000 Leuven, Belgium
| | - Filip Struyf
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, B-2610 Wilrijk, Belgium
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17
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Soler-Martínez R, Deulofeu M, Bagó-Mas A, Dubový P, Verdú E, Fiol N, Boadas-Vaello P. Central Neuropathic Pain Development Modulation Using Coffee Extract Major Polyphenolic Compounds in Spinal-Cord-Injured Female Mice. BIOLOGY 2022; 11:1617. [PMID: 36358318 PMCID: PMC9687351 DOI: 10.3390/biology11111617] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 08/18/2024]
Abstract
It was recently shown that coffee polyphenolic extract exerts preventive effects on central neuropathic pain development, but it is unknown whether its beneficial effects are associated with only one of its major polyphenolic compounds or if the whole extract is needed to exert such effects. The main objective of this study was to determine whether the separate administration of major polyphenols from coffee extract exerts preventive effects on the development of central neuropathic pain in mice compared with the effects of the whole coffee extract. Thus, spinal-cord-injured female ICR-CD1 mice were daily treated with either coffee extract or its major polyphenolic compounds during the first week, and reflexive and nonreflexive pain responses were evaluated within the acute phase of spinal cord injury. In addition, the injury-induced gliosis and dorsal horn sprouting were evaluated with immunohistochemistry. The results showed that the coffee extract prevented spinal cord injury-induced neuropathic pain, whereas its major polyphenolic compounds resulted in reflexive pain response attenuation. Both preventive and attenuation effects were associated with gliosis and afferent fiber sprouting modulation. Overall, the results suggested that coffee extract effects may be associated with potential synergistic mechanisms exerted by its major polyphenolic compounds and not by the sole effect of only one of them.
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Affiliation(s)
- Roger Soler-Martínez
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain
| | - Meritxell Deulofeu
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain
| | - Anna Bagó-Mas
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain
| | - Petr Dubový
- Department of Anatomy, Division of Neuroanatomy, Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Enrique Verdú
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain
| | - Núria Fiol
- Department of Chemical Engineering, Agriculture and Food Technology, Polytechnic School, University of Girona, E-17003 Girona, Catalonia, Spain
| | - Pere Boadas-Vaello
- Research Group of Clinical Anatomy, Embryology and Neuroscience (NEOMA), Department of Medical Sciences, University of Girona, E-17003 Girona, Catalonia, Spain
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18
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Kawakami K, Tanaka S, Sugiyama Y, Mochizuki N, Kawamata M. Intrathecal morphine exacerbates paresis with increasing muscle tone of hindlimbs in rats with mild thoracic spinal cord injury but without damage of lumbar α-motoneurons. PLoS One 2022; 17:e0273095. [PMID: 35969631 PMCID: PMC9377624 DOI: 10.1371/journal.pone.0273095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 08/02/2022] [Indexed: 11/25/2022] Open
Abstract
Adverse effects of morphine on locomotor function after moderate to severe spinal cord injury (SCI) have been reported; however, the effects after mild SCI without damage of lumbar α-motoneurons have not been investigated. We investigated the effects of lumbar intrathecal morphine on locomotor function after mild thoracic SCI and the involvement of classic opioid receptor activation. A mild thoracic contusive SCI was induced in adult rats at the T9-T10 spine level under sevoflurane anesthesia. We evaluated the effects of single doses of intrathecal morphine and selective μ-, δ-, and κ-opioid receptor agonists, continuous infusion of intrathecal morphine for 72 hours, and administration of physiological saline on locomotor function and muscle tone in the hindlimbs. The numbers of damaged and total α-motoneurons in the lumbar spinal cord were also investigated. Single doses of morphine aggravated residual locomotor function after SCI but did not affect functional recovery. Single doses of morphine and μ- and δ-opioid receptor agonists significantly aggravated residual locomotor function with increases in muscle tone after SCI, and the effects of the drugs were reversed by naloxone. In contrast, continuous infusion of morphine led to persistent decline in locomotor function with increased muscle tone, which was not reversed by naloxone, but did not increase the number of damaged lumbar α-motoneurons. These results indicate that a single dose of morphine at an analgesic dose transiently increases muscle tone of the hindlimbs via activation of spinal μ- and δ- opioid receptors, resulting in further deterioration of locomotor function in the acute phase of mild SCI. Our results also suggest that an increased dose of morphine with prolonged administration leads to persistent decline in locomotor function with increased muscle tone via mechanisms other than direct activation of classical opioid receptors. Morphine should be used cautiously even after mild SCI.
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Affiliation(s)
- Katsuhiro Kawakami
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Satoshi Tanaka
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
- * E-mail:
| | - Yuki Sugiyama
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Noriaki Mochizuki
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Mikito Kawamata
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
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19
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Noble BT, Brennan FH, Wang Y, Guan Z, Mo X, Schwab JM, Popovich PG. Thoracic VGluT2 + Spinal Interneurons Regulate Structural and Functional Plasticity of Sympathetic Networks after High-Level Spinal Cord Injury. J Neurosci 2022; 42:3659-3675. [PMID: 35304427 PMCID: PMC9053847 DOI: 10.1523/jneurosci.2134-21.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/25/2022] [Accepted: 02/28/2022] [Indexed: 11/21/2022] Open
Abstract
Traumatic spinal cord injury (SCI) above the major spinal sympathetic outflow (T6 level) disinhibits sympathetic neurons from supraspinal control, causing systems-wide "dysautonomia." We recently showed that remarkable structural remodeling and plasticity occurs within spinal sympathetic circuitry, creating abnormal sympathetic reflexes that exacerbate dysautonomia over time. As an example, thoracic VGluT2+ spinal interneurons (SpINs) become structurally and functionally integrated with neurons that comprise the spinal-splenic sympathetic network and immunological dysfunction becomes progressively worse after SCI. To test whether the onset and progression of SCI-induced sympathetic plasticity is neuron activity dependent, we selectively inhibited (or excited) thoracic VGluT2+ interneurons using chemogenetics. New data show that silencing VGluT2+ interneurons in female and male mice with a T3 SCI, using hM4Di designer receptors exclusively activated by designer drugs (Gi DREADDs), blocks structural plasticity and the development of dysautonomia. Specifically, silencing VGluT2+ interneurons prevents the structural remodeling of spinal sympathetic networks that project to lymphoid and endocrine organs, reduces the frequency of spontaneous autonomic dysreflexia (AD), and reduces the severity of experimentally induced AD. Features of SCI-induced structural plasticity can be recapitulated in the intact spinal cord by activating excitatory hM3Dq-DREADDs in VGluT2+ interneurons. Collectively, these data implicate VGluT2+ excitatory SpINs in the onset and propagation of SCI-induced structural plasticity and dysautonomia, and reveal the potential for neuromodulation to block or reduce dysautonomia after severe high-level SCI.SIGNIFICANCE STATEMENT In response to stress or dangerous stimuli, autonomic spinal neurons coordinate a "fight or flight" response marked by increased cardiac output and release of stress hormones. After a spinal cord injury (SCI), normally harmless stimuli like bladder filling can result in a "false" fight or flight response, causing pathological changes throughout the body. We show that progressive hypertension and immune suppression develop after SCI because thoracic excitatory VGluT2+ spinal interneurons (SpINs) provoke structural remodeling in autonomic networks within below-lesion spinal levels. These pathological changes can be prevented in SCI mice or phenocopied in uninjured mice using chemogenetics to selectively manipulate activity in VGluT2+ SpINs. Targeted neuromodulation of SpINs could prevent structural plasticity and subsequent autonomic dysfunction in people with SCI.
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Affiliation(s)
- Benjamin T Noble
- Department of Neuroscience, Center for Brain and Spinal Cord Repair, Belford Center for Spinal Cord Injury, Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210
| | - Faith H Brennan
- Department of Neuroscience, Center for Brain and Spinal Cord Repair, Belford Center for Spinal Cord Injury, Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210
| | - Yan Wang
- Department of Neuroscience, Center for Brain and Spinal Cord Repair, Belford Center for Spinal Cord Injury, Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210
| | - Zhen Guan
- Department of Neuroscience, Center for Brain and Spinal Cord Repair, Belford Center for Spinal Cord Injury, Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210
| | - Xiaokui Mo
- Center for Biostatistics, The Ohio State University, Columbus, Ohio 43210
| | - Jan M Schwab
- Department of Neurology, Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210
| | - Phillip G Popovich
- Department of Neuroscience, Center for Brain and Spinal Cord Repair, Belford Center for Spinal Cord Injury, Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210
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20
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Dietz V, Knox K, Moore S, Roberts N, Corona KK, Dulin JN. Dorsal horn neuronal sparing predicts the development of at-level mechanical allodynia following cervical spinal cord injury in mice. Exp Neurol 2022; 352:114048. [PMID: 35304102 DOI: 10.1016/j.expneurol.2022.114048] [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: 12/13/2021] [Revised: 03/03/2022] [Accepted: 03/13/2022] [Indexed: 11/04/2022]
Abstract
Spinal cord injury (SCI) frequently results in immediate and sustained neurological dysfunction, including intractable neuropathic pain in approximately 60-80% of individuals. SCI induces immediate mechanical damage to spinal cord tissue followed by a period of secondary injury in which tissue damage is further propagated, contributing to the development of anatomically unique lesions. Variability in lesion size and location influences the degree of motor and sensory dysfunction incurred by an individual. We predicted that variability in lesion parameters may also explain why some, but not all, experimental animals develop mechanical sensitivity after SCI. To characterize the relationship of lesion anatomy to mechanical allodynia, we utilized a mouse cervical hemicontusion model of SCI that has been shown to lead to the development and persistence of mechanical allodynia in the ipsilateral forelimb after injury. At four weeks post-SCI, the numbers and locations of surviving neurons were quantified along with total lesion volume and nociceptive fiber sprouting. We found that the subset of animals exhibiting mechanical allodynia had significantly increased neuronal sparing in the ipsilateral dorsal horn around the lesion epicenter compared to animals that did not exhibit mechanical allodynia. Additionally, we failed to observe significant differences between groups in nociceptive fiber density in the dorsal horn around the lesion epicenter. Notably, we found that impactor probe displacement upon administration of the SCI surgery was significantly lower in sensitive animals compared with not-sensitive animals. Together, our data indicate that lesion severity negatively correlates with the manifestation of at-level mechanical hypersensitivity and suggests that sparing of dorsal horn neurons may be required for the development of neuropathic pain.
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Affiliation(s)
- Valerie Dietz
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Katelyn Knox
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Sherilynne Moore
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Nolan Roberts
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | | | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA.
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21
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Burns M, Solinsky R. Toward rebalancing blood pressure instability after spinal cord injury with spinal cord electrical stimulation: A mini review and critique of the evolving literature. Auton Neurosci 2022; 237:102905. [PMID: 34800845 PMCID: PMC9280330 DOI: 10.1016/j.autneu.2021.102905] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/07/2021] [Accepted: 11/06/2021] [Indexed: 01/03/2023]
Abstract
High-level spinal cord injury commonly leads to blood pressure instability. This manifests clinically as orthostatic hypotension (OH), where blood pressure can drop to the point of loss of consciousness, and autonomic dysreflexia (AD), where systolic blood pressure can climb to over 300 mmHg in response to an unperceived noxious stimulus. These blood pressure fluctuations can occur multiple times a day, contributing to increased vessel shear stress and heightened risk of cardiovascular disease. The pathophysiology of both of these conditions is rooted in impairments in regulation of spinal cord sympathetic preganglionic neurons, which control blood pressure by mediating vascular resistance and catecholamine release. Recently, spinal cord electrical stimulation has provided evidence that it may modulate these blood pressure imbalances. Early proposed mechanisms suggest activation of spinal cord dorsal horn neurons that ultimately act upon the sympathetic preganglionic neuronal pathways. For OH, spinal cord stimulation likely induces local activation of these neurons to generate baseline sympathetic tone and accompanying vasoconstriction. The mechanisms for spinal stimulation regulating AD are less clear, though some suggest it activates inhibitory circuits to dampen the overactive sympathetic response. While questions remain, spinal cord electrical stimulation is an intriguing new modality that may restore blood pressure regulation following spinal cord injury.
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Affiliation(s)
- Madeleine Burns
- Boston University School of Medicine, Graduate Medical Sciences
| | - Ryan Solinsky
- Spaulding Rehabilitation Hospital,Department of Physical Medicine & Rehabilitation, Harvard Medical School,Spaulding Research Institute
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22
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Trbovich M, Wu Y, Koek W, Zhao J, Kellogg D. Impact of tetraplegia vs. paraplegia on venoarteriolar, myogenic and maximal cutaneous vasodilation responses of the microvasculature: Implications for cardiovascular disease. J Spinal Cord Med 2022; 45:49-57. [PMID: 32496962 PMCID: PMC8890560 DOI: 10.1080/10790268.2020.1761173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Objective: Cardiovascular disease (CVD) is a leading cause of mortality in persons with SCI. While macrovascular remodeling and function after SCI is well documented, changes in the microvascular structure and function are comparably understudied, but importantly predict CVD risk. Specifically, the integrity of venoarteriolar (VAR), myogenic (MYO) and maximal vasodilation responses are largely unknown after SCI, especially in persons with tetraplegia (TP) at highest risk of CVD. This is the first to examine the differences in VAR (cuff inflation), MYO (limb dependency) and maximal vasodilation responses of the microvasculature between able bodied (AB) versus those with TP and paraplegia (PP).Design: Observational.Setting: Laboratory.Participants: Eight AB, 6 TP, and 8 PP persons.Interventions: One forearm and calf were treated topically with lidocaine 2.5%/prilocaine 2.5% while contralateral limb served as a control. Laser doppler flowmeters were applied over treated and control sites during limb dependency, cuff inflation and local skin heating (Tloc) up to 42°C.Outcome measures: Skin vascular resistance (SkVR) change with cuff inflation and limb dependency and maximal cutaneous vascular conductance (CVC) during local heating.Results: Change in SkVR was not significantly different between groups or extremity (upper vs. lower) during cuff inflation or limb dependency. However, CVC at Tloc 42°C was significantly different in the lower extremity (LE) of TP and PP (P = 0.007, 0.35) compared to AB.Conclusion: Increases in SkVR during cuff inflation (VAR) and limb dependency (VAR and MYO) are unaltered after SCI, however maximal vasodilation in the LE post-SCI is higher than AB persons.
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Affiliation(s)
- Michelle Trbovich
- Department of Rehabilitation Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA,Correspondence to: Michelle Trbovich, Department of Rehabilitation Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio78229, TX, USA.
| | - Yubo Wu
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Wouter Koek
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Joan Zhao
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Dean Kellogg
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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23
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Shepard CT, Pocratsky AM, Brown BL, Van Rijswijck MA, Zalla RM, Burke DA, Morehouse JR, Riegler AS, Whittemore SR, Magnuson DSK. Silencing long ascending propriospinal neurons after spinal cord injury improves hindlimb stepping in the adult rat. eLife 2021; 10:e70058. [PMID: 34854375 PMCID: PMC8639151 DOI: 10.7554/elife.70058] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 11/23/2021] [Indexed: 12/11/2022] Open
Abstract
Long ascending propriospinal neurons (LAPNs) are a subpopulation of spinal cord interneurons that directly connect the lumbar and cervical enlargements. Previously we showed, in uninjured animals, that conditionally silencing LAPNs disrupted left-right coordination of the hindlimbs and forelimbs in a context-dependent manner, demonstrating that LAPNs secure alternation of the fore- and hindlimb pairs during overground stepping. Given the ventrolateral location of LAPN axons in the spinal cord white matter, many likely remain intact following incomplete, contusive, thoracic spinal cord injury (SCI), suggesting a potential role in the recovery of stepping. Thus, we hypothesized that silencing LAPNs after SCI would disrupt recovered locomotion. Instead, we found that silencing spared LAPNs post-SCI improved locomotor function, including paw placement order and timing, and a decrease in the number of dorsal steps. Silencing also restored left-right hindlimb coordination and normalized spatiotemporal features of gait such as stance and swing time. However, hindlimb-forelimb coordination was not restored. These data indicate that the temporal information carried between the spinal enlargements by the spared LAPNs post-SCI is detrimental to recovered hindlimb locomotor function. These findings are an illustration of a post-SCI neuroanatomical-functional paradox and have implications for the development of neuronal- and axonal-protective therapeutic strategies and the clinical study/implementation of neuromodulation strategies.
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Affiliation(s)
- Courtney T Shepard
- Interdisciplinary Program in Translational Neuroscience, School of Interdisciplinary and Graduate Studies, University of LouisvilleLouisvilleUnited States
- Department of Anatomical Sciences and Neurobiology, University of Louisville, LouisvilleLouisvilleUnited States
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
| | - Amanda M Pocratsky
- Department of Anatomical Sciences and Neurobiology, University of Louisville, LouisvilleLouisvilleUnited States
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
| | - Brandon L Brown
- Interdisciplinary Program in Translational Neuroscience, School of Interdisciplinary and Graduate Studies, University of LouisvilleLouisvilleUnited States
- Department of Anatomical Sciences and Neurobiology, University of Louisville, LouisvilleLouisvilleUnited States
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
| | - Morgan A Van Rijswijck
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Speed School of Engineering, University of LouisvilleLouisvilleUnited States
| | - Rachel M Zalla
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Speed School of Engineering, University of LouisvilleLouisvilleUnited States
| | - Darlene A Burke
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Department of Neurological Surgery, University of LouisvilleLouisvilleUnited States
| | - Johnny R Morehouse
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Department of Neurological Surgery, University of LouisvilleLouisvilleUnited States
| | - Amberley S Riegler
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Department of Neurological Surgery, University of LouisvilleLouisvilleUnited States
| | - Scott R Whittemore
- Interdisciplinary Program in Translational Neuroscience, School of Interdisciplinary and Graduate Studies, University of LouisvilleLouisvilleUnited States
- Department of Anatomical Sciences and Neurobiology, University of Louisville, LouisvilleLouisvilleUnited States
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Department of Neurological Surgery, University of LouisvilleLouisvilleUnited States
| | - David SK Magnuson
- Interdisciplinary Program in Translational Neuroscience, School of Interdisciplinary and Graduate Studies, University of LouisvilleLouisvilleUnited States
- Department of Anatomical Sciences and Neurobiology, University of Louisville, LouisvilleLouisvilleUnited States
- Kentucky Spinal Cord Injury Research Center, University of LouisvilleLouisvilleUnited States
- Speed School of Engineering, University of LouisvilleLouisvilleUnited States
- Department of Neurological Surgery, University of LouisvilleLouisvilleUnited States
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24
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Guo F, Zheng X, He Z, Zhang R, Zhang S, Wang M, Chen H, Wang W. Nimodipine Promotes Functional Recovery After Spinal Cord Injury in Rats. Front Pharmacol 2021; 12:733420. [PMID: 34594224 PMCID: PMC8477750 DOI: 10.3389/fphar.2021.733420] [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: 06/30/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that results in severe motor, sensory, and autonomic dysfunction. The L-/T-type calcium channel blocker nimodipine (NMD) exerts a protective effect on neuronal injury; however, the protective effects of long-term administration of NMD in subjects with SCI remain unknown. Thus, the aim of this study was to evaluate the role of long-term treatment with NMD on a clinically relevant SCI model. Female rats with SCI induced by 25 mm contusion were subcutaneously injected with vehicle or 10 mg/kg NMD daily for six consecutive weeks. We monitored the motor score, hind limb grip strength, pain-related behaviors, and bladder function in this study to assess the efficacy of NMD in rats with SCI. Rats treated with NMD showed improvements in locomotion, pain-related behaviors, and spasticity-like symptoms, but not in open-field spontaneous activity, hind limb grip strength or bladder function. SCI lesion areas and perilesional neuronal numbers, gliosis and calcitonin gene-related peptide (CGRP+) fiber sprouting in the lumbar spinal cord and the expression of K+–Cl− cotransporter 2 (KCC2) on lumbar motor neurons were also observed to further explore the possible protective mechanisms of NMD. NMD-treated rats showed greater tissue preservation with reduced lesion areas and increased perilesional neuronal sparing. NMD-treated rats also showed improvements in gliosis, CGRP+ fiber sprouting in the lumbar spinal cord, and KCC2 expression in lumbar motor neurons. Together, these results indicate that long-term treatment with NMD improves functional recovery after SCI, which may provide a potential therapeutic strategy for the treatment of SCI.
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Affiliation(s)
- Fangliang Guo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaolong Zheng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ziyu He
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ruoying Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Song Zhang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minghuan Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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25
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Kajtaz E, Montgomery LR, McMurtry S, Howland DR, Nichols TR. Non-uniform upregulation of the autogenic stretch reflex among hindlimb extensors following lateral spinal lesion in the cat. Exp Brain Res 2021; 239:2679-2691. [PMID: 34218298 PMCID: PMC9805805 DOI: 10.1007/s00221-020-06016-1] [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: 06/19/2020] [Accepted: 12/09/2020] [Indexed: 01/04/2023]
Abstract
Successful propagation throughout the step cycle is contingent on adequate regulation of whole-limb stiffness by proprioceptive feedback. Following spinal cord injury (SCI), there are changes in the strength and organization of proprioceptive feedback that can result in altered joint stiffness. In this study, we measured changes in autogenic feedback of five hindlimb extensor muscles following chronic low thoracic lateral hemisection (LSH) in decerebrate cats. We present three features of the autogenic stretch reflex obtained using a mechanographic method. Stiffness was a measure of the resistance to stretch during the length change. The dynamic index documented the extent of adaptation or increase of the force response during the hold phase, and the impulse measured the integral of the response from initiation of a stretch to the return to the initial length. The changes took the form of variable and transient increases in the stiffness of vastus (VASTI) group, soleus (SOL), and flexor hallucis longus (FHL), and either increased (VASTI) or decreased adaptation (GAS and PLANT). The stiffness of the gastrocnemius group (GAS) was also variable over time but remained elevated at the final time point. An unexpected finding was that these effects were observed bilaterally. Potential reasons for this finding and possible sources of increased excitability to this muscle group are discussed.
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Affiliation(s)
- E Kajtaz
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30318, USA
| | - L R Montgomery
- Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, The University of Louisville, Louisville, KY, USA
- Research Service, Robley Rex VA Medical Center, Louisville, KY, USA
| | - S McMurtry
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30318, USA
| | - D R Howland
- Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, The University of Louisville, Louisville, KY, USA
- Research Service, Robley Rex VA Medical Center, Louisville, KY, USA
| | - T Richard Nichols
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30318, USA.
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26
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Kayaci S, Aydin MD, Ozoner B, Cakir T, Bas O, Sipal S. Relationship between subarachnoid and central canal hemorrhage and spasticity: A first experimental study. J Spinal Cord Med 2021; 44:748-756. [PMID: 31647747 PMCID: PMC8477948 DOI: 10.1080/10790268.2019.1669956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Objective: Spastic disorders are considered as important cerebral complications of subarachnoid hemorrhage (SAH). However, there has been no research concerning the pathophysiological mechanism of its link with the spinal cord. The present study aimed to assess the relationship between the development of spasticity and neuronal degeneration after SAH and increase in spinal cord pressure after central canal hemorrhage (CCH).Participants: Twenty-three rabbits were included.Outcome measures: Of all rabbits, 5, 5, and 13 were allocated in the control, SHAM and study groups, respectively. Moreover, 1 cc of saline and 1 cc of autologous arterial blood were injected into the cisterna magna of the SHAM and study groups, respectively. The Muscle spasticity tension values (MSTVs) were determined according to the modified Ashworth scale. Degenerated neuron densities (DND) in the gray matter (GM) of each animal's spinal cord were stereologically calculated.Results: The average MSTV of each group was as follows: control group (n = 5) 2; SHAM group (n = 5) 3-5; and study group (n = 13) 8-10. The DND values of the spinal cord of each group were as follows: control group, 2 ± 1/mm3; SHAM group, 12 ± 3/mm3; and study group, 34 ± 9/mm3. Results showed an important linear relationship between the MSTVs and the DND of the spinal cord (P < 0.001).Conclusion: Spasticity may be attributed to other causes such as ischemic neurodegenerative process that develops after spinal SAH and the de-synchronization of the flexor-extensor muscles due to the spontaneous discharge of interneuronal structures, which are crossed within the spinal cord owing to the build-up of pressure after CCH.
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Affiliation(s)
- Selim Kayaci
- Department of Neurosurgery Medical, Faculty of Erzincan Binali Yıldırım University, Erzincan, Turkey,Correspondence to: Selim Kayaci, Department of Neurosurgery Medical, Faculty of Erzincan Binali Yıldırım University, 24100 Erzincan, Turkey; Ph: 0446 212 22 22.
| | - Mehmet Dumlu Aydin
- Department of Neurosurgery, Medical Faculty of Ataturk University, Erzurum, Turkey,Mehmet Dumlu Aydin, Department of Neurosurgery, Medical Faculty of Ataturk University, Erzurum, Turkey.
| | - Baris Ozoner
- Department of Neurosurgery Medical, Faculty of Erzincan Binali Yıldırım University, Erzincan, Turkey
| | - Tayfun Cakir
- Department of Neurosurgery Medical, Faculty of Erzincan Binali Yıldırım University, Erzincan, Turkey
| | - Orhan Bas
- Department of Anatomy, Medical Faculty of Ordu University, Ordu, Turkey
| | - Sare Sipal
- Department of Pathology, Medical Faculty of Ataturk University, Erzurum, Turkey
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27
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O'Reilly ML, Mironets E, Shapiro TM, Crowther K, Collyer E, Bethea JR, Tom VJ. Pharmacological Inhibition of Soluble Tumor Necrosis Factor-Alpha Two Weeks after High Thoracic Spinal Cord Injury Does Not Affect Sympathetic Hyperreflexia. J Neurotrauma 2021; 38:2186-2191. [PMID: 33397170 PMCID: PMC8309421 DOI: 10.1089/neu.2020.7504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After a severe, high-level spinal cord injury (SCI), plasticity to intraspinal circuits below injury results in heightened spinal sympathetic reflex activity and detrimentally impacts peripheral organ systems. Such sympathetic hyperreflexia is immediately apparent as an episode of autonomic dysreflexia (AD), a life-threatening condition characterized by sudden hypertension and reflexive bradycardia following below-level sensory inputs; for example, pressure sores or impacted fecal matter. Over time, plasticity within the spinal sympathetic reflex (SSR) circuit contributes to the progressive intensification of AD events, as the frequency and severity of AD events increase greatly beginning ∼2 weeks post-injury (wpi). The neuroimmune system has been implicated in driving sympathetic hyperreflexia, as inhibition of the cytokine soluble tumor necrosis factor-alpha (sTNFα) using the biological mimetic XPro1595 beginning within days post-SCI has been shown to attenuate the development of AD. Here, we sought to further understand the effective therapeutic time window of XPro1595 to diminish sympathetic hyperreflexia, as indicated by AD. We delayed the commencement of continuous intrathecal administration of XPro1595 until 2 weeks after a complete, thoracic level 3 injury in adult rats. We examined the severity of colorectal distension-induced AD biweekly. We found that initiation of sTNFα inhibition at 2 wpi does not attenuate the severity or intensification of sympathetic hyperreflexia compared with saline-treated controls. Coupled with previous data from our group, these findings suggest that central sTNFα signaling must be targeted prior to 2 weeks post-SCI in order to decrease sympathetic hyperreflexia.
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Affiliation(s)
- Micaela L. O'Reilly
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Eugene Mironets
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Tatiana M. Shapiro
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Kallon Crowther
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Eileen Collyer
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - John R. Bethea
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Veronica J. Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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28
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Garcia-Ramirez DL, Ha NT, Bibu S, Stachowski NJ, Dougherty KJ. Spinal Cord Injury Alters Spinal Shox2 Interneurons by Enhancing Excitatory Synaptic Input and Serotonergic Modulation While Maintaining Intrinsic Properties in Mouse. J Neurosci 2021; 41:5833-5848. [PMID: 34006587 PMCID: PMC8265802 DOI: 10.1523/jneurosci.1576-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Abstract
Neural circuitry generating locomotor rhythm and pattern is located in the spinal cord. Most spinal cord injuries (SCIs) occur above the level of spinal locomotor neurons; therefore, these circuits are a target for improving motor function after SCI. Despite being relatively intact below the injury, locomotor circuitry undergoes substantial plasticity with the loss of descending control. Information regarding cell type-specific plasticity within locomotor circuits is limited. Shox2 interneurons (INs) have been linked to locomotor rhythm generation and patterning, making them a potential therapeutic target for the restoration of locomotion after SCI. The goal of the present study was to identify SCI-induced plasticity at the level of Shox2 INs in a complete thoracic transection model in adult male and female mice. Whole-cell patch-clamp recordings of Shox2 INs revealed minimal changes in intrinsic excitability properties after SCI. However, afferent stimulation resulted in mixed excitatory and inhibitory input to Shox2 INs in uninjured mice which became predominantly excitatory after SCI. Shox2 INs were differentially modulated by serotonin (5-HT) in a concentration-dependent manner in uninjured conditions but following SCI, 5-HT predominantly depolarized Shox2 INs. 5-HT7 receptors mediated excitatory effects on Shox2 INs from both uninjured and SCI mice, but activation of 5-HT2B/2C receptors enhanced excitability of Shox2 INs only after SCI. Overall, SCI alters sensory afferent input pathways to Shox2 INs and 5-HT modulation of Shox2 INs to enhance excitatory responses. Our findings provide relevant information regarding the locomotor circuitry response to SCI that could benefit strategies to improve locomotion after SCI.SIGNIFICANCE STATEMENT Current therapies to gain locomotor control after spinal cord injury (SCI) target spinal locomotor circuitry. Improvements in therapeutic strategies will require a better understanding of the SCI-induced plasticity within specific locomotor elements and their controllers, including sensory afferents and serotonergic modulation. Here, we demonstrate that excitability and intrinsic properties of Shox2 interneurons, which contribute to the generation of the locomotor rhythm and pattering, remain intact after SCI. However, SCI induces plasticity in both sensory afferent pathways and serotonergic modulation, enhancing the activation and excitation of Shox2 interneurons. Our findings will impact future strategies looking to harness these changes with the ultimate goal of restoring functional locomotion after SCI.
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Affiliation(s)
- D Leonardo Garcia-Ramirez
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Ngoc T Ha
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Steve Bibu
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Nicholas J Stachowski
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Kimberly J Dougherty
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
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Ueno M. Restoring neuro-immune circuitry after brain and spinal cord injuries. Int Immunol 2021; 33:311-325. [PMID: 33851981 DOI: 10.1093/intimm/dxab017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/13/2021] [Indexed: 12/17/2022] Open
Abstract
Neuro-immune interactions are essential for our body's defense and homeostasis. Anatomical and physiological analyses have shown that the nervous system comprises multiple pathways that regulate the dynamics and functions of immune cells, which are mainly mediated by the autonomic nervous system and adrenal signals. These are disturbed when the neurons and circuits are damaged by diseases of the central nervous system (CNS). Injuries caused by stroke or trauma often cause immune dysfunction by abrogation of the immune-regulating neural pathways, which leads to an increased risk of infections. Here, I review the structures and functions of the neural pathways connecting the brain and the immune system, and the neurogenic mechanisms of immune dysfunction that emerge after CNS injuries. Recent technological advances in manipulating specific neural circuits have added mechanistic aspects of neuro-immune interactions and their dysfunctions. Understanding the neural bases of immune control and their pathological processes will deepen our knowledge of homeostasis and lead to the development of strategies to cure immune deficiencies observed in various CNS disorders.
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Affiliation(s)
- Masaki Ueno
- Department of System Pathology for Neurological Disorders, Brain Research Institute, Niigata University, Niigata, Niigata 951-8585, Japan
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Brennan FH, Noble BT, Wang Y, Guan Z, Davis H, Mo X, Harris C, Eroglu C, Ferguson AR, Popovich PG. Acute post-injury blockade of α2δ-1 calcium channel subunits prevents pathological autonomic plasticity after spinal cord injury. Cell Rep 2021; 34:108667. [PMID: 33503436 PMCID: PMC8817229 DOI: 10.1016/j.celrep.2020.108667] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/16/2020] [Accepted: 12/28/2020] [Indexed: 12/14/2022] Open
Abstract
After spinal cord injury (SCI), normally innocuous visceral or somatic stimuli can trigger uncontrolled reflex activation of sympathetic circuitry, causing pathological dysautonomia. We show that remarkable structural remodeling and plasticity occur within spinal autonomic circuitry, creating abnormal sympathetic reflexes that promote dysautonomia. However, when mice are treated early after SCI with human-equivalent doses of the US Food and Drug Administration (FDA)-approved drug gabapentin (GBP), it is possible to block multi-segmental excitatory synaptogenesis and abolish sprouting of autonomic neurons that innervate immune organs and sensory afferents that trigger pain and autonomic dysreflexia (AD). This “prophylactic GBP” regimen decreases the frequency and severity of AD and protects against SCI-induced immune suppression. These benefits persist even 1 month after stopping treatment. GBP could be repurposed to prevent dysautonomia in at-risk individuals with high-level SCI. Brennan et al. show that α2δ−1 calcium channel subunits drive remarkable structural reorganization of autonomic circuitry and autonomic dysfunction after spinal cord injury. Early (prophylactic) post-injury treatment with gabapentin, an FDA-approved drug, prevents α2δ−1-dependent structural changes and autonomic dysfunction. Prophylactic gabapentin could be repurposed clinically for at-risk individuals.
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Affiliation(s)
- Faith H Brennan
- Department of Neuroscience, Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, OH 43210, USA
| | - Benjamin T Noble
- Department of Neuroscience, Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, OH 43210, USA
| | - Yan Wang
- Department of Neuroscience, Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, OH 43210, USA
| | - Zhen Guan
- Department of Neuroscience, Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, OH 43210, USA
| | - Hayes Davis
- Department of Neuroscience, Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, OH 43210, USA
| | - Xiaokui Mo
- Center for Biomedical Informatics, The Ohio State University, Columbus, OH 43210, USA
| | - Clay Harris
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, and Duke Institute for Brain Sciences, Durham, NC 27710, USA
| | - Adam R Ferguson
- Brain and Spinal Injury Center (BASIC), Department of Neurological Surgery, Weill Institute for Neurosciences, University of California, San Francisco (UCSF), San Francisco, CA 94142, USA; San Francisco Veterans Affairs Healthcare System (SFVAHCS), San Francisco, CA, USA
| | - Phillip G Popovich
- Department of Neuroscience, Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, OH 43210, USA.
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O'Reilly ML, Tom VJ. Neuroimmune System as a Driving Force for Plasticity Following CNS Injury. Front Cell Neurosci 2020; 14:187. [PMID: 32792908 PMCID: PMC7390932 DOI: 10.3389/fncel.2020.00187] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/29/2020] [Indexed: 12/15/2022] Open
Abstract
Following an injury to the central nervous system (CNS), spontaneous plasticity is observed throughout the neuraxis and affects multiple key circuits. Much of this spontaneous plasticity can elicit beneficial and deleterious functional outcomes, depending on the context of plasticity and circuit affected. Injury-induced activation of the neuroimmune system has been proposed to be a major factor in driving this plasticity, as neuroimmune and inflammatory factors have been shown to influence cellular, synaptic, structural, and anatomical plasticity. Here, we will review the mechanisms through which the neuroimmune system mediates plasticity after CNS injury. Understanding the role of specific neuroimmune factors in driving adaptive and maladaptive plasticity may offer valuable therapeutic insight into how to promote adaptive plasticity and/or diminish maladaptive plasticity, respectively.
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Affiliation(s)
- Micaela L O'Reilly
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
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Meehan CF, Ford TW, Kirkwood PA. Plasticity of thoracic interneurones rostral to a lateral spinal cord lesion. Exp Neurol 2020; 331:113361. [PMID: 32464119 DOI: 10.1016/j.expneurol.2020.113361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 05/03/2020] [Accepted: 05/17/2020] [Indexed: 01/14/2023]
Abstract
The morphology and projections of ventral horn interneurones in the segment above an ipsilateral thoracic lateral spinal cord lesion were studied in the cat by intracellular injections of Neurobiotin at 6 to 18 weeks post-lesion and compared with previously published control data from uninjured spinal cords. The cell axons ascended, descended or both, mostly contralaterally and mostly spared by the lesion. Unusual morphological dendritic features were seen in the lesion group, mostly growth-related, including complex dendritic appendages, twisted or multiple-branched terminal dendrites, commissural dendrites, apparently swollen proximal dendrites and rostrocaudal asymmetries. Significant quantitative differences included more dendritic spines in the lesion group (3.4×) and smaller soma areas in the lesion group (with similar numbers of primary dendrites and rostrocaudal dendritic spans). Immunoreactivity to microtubule associated protein 2a/b was detected in the proximal, but not distal, dendrites of cells in the lesion group, corresponding to an overall decrease in immunoreactivity in the ventral horns on the lesion side compared to the other. For axon collaterals, significant increases for the lesion group were seen in the number of collaterals in the first 4 mm of axon and in the area of ventral/intermediate horn occupied by terminals, including increased innervation of some regions, among which were the intermediolateral columns. This dendritic and axonal plasticity makes the interneuones candidates for a role in detour circuits but also for a maladaptive role in autonomic hyperreflexia.
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Affiliation(s)
- Claire Francesca Meehan
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| | - Timothy W Ford
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Peter A Kirkwood
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Sachdeva R, Hutton G, Marwaha AS, Krassioukov AV. Morphological maladaptations in sympathetic preganglionic neurons following an experimental high-thoracic spinal cord injury. Exp Neurol 2020; 327:113235. [PMID: 32044331 DOI: 10.1016/j.expneurol.2020.113235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 01/15/2020] [Accepted: 02/06/2020] [Indexed: 10/25/2022]
Abstract
Spinal cord injury (SCI) disrupts the supraspinal vasomotor pathways to sympathetic preganglionic neurons (SPNs) leading to impaired blood pressure (BP) control that often results in episodes of autonomic dysreflexia and orthostatic hypotension. The physiological cardiovascular consequences of SCI are largely attributed to the plastic changes in spinal SPNs induced by their partial deafferentation. While multiple studies have investigated the morphological changes in SPNs following SCI with contrasting reports. Here we investigated the morphological changes in SPNs rostral and caudal to a high thoracic (T3) SCI at 1-, 4- and 8-weeks post injury. SPNs were identified using Nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH- diaphorase) staining and were quantified for soma size and various dendritic measurements. We show that rostral to the lesion, soma size was increased at 1 week along with increased dendritic arbor. The total dendritic length was also increased at chronic stage (8 weeks post SCI). Caudal to the lesion, the soma size or dendritic lengths did not change with SCI. However, dendritic branching was enhanced within a week post SCI and remained elevated throughout the chronic stages. These findings demonstrate that SPNs undergo significant structural changes form sub-acute to chronic stages post-SCI that likely determines their functional consequences. These changes are discussed in context of physiological cardiovascular outcomes post-SCI.
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Affiliation(s)
- Rahul Sachdeva
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Gillian Hutton
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Arshdeep S Marwaha
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada; Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, Canada; GF Strong Rehabilitation Center, Vancouver Coastal Health, Vancouver, Canada.
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Grafting Embryonic Raphe Neurons Reestablishes Serotonergic Regulation of Sympathetic Activity to Improve Cardiovascular Function after Spinal Cord Injury. J Neurosci 2020; 40:1248-1264. [PMID: 31896670 DOI: 10.1523/jneurosci.1654-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 12/16/2022] Open
Abstract
Cardiovascular dysfunction often occurs after high-level spinal cord injury. Disrupting supraspinal vasomotor pathways affects basal hemodynamics and contributes to the development of autonomic dysreflexia (AD). Transplantation of early-stage neurons to the injured cord may reconstruct the descending projections to enhance cardiovascular performance. To determine the specific role of reestablishing serotonergic regulation of hemodynamics, we implanted serotonergic (5-HT+) neuron-enriched embryonic raphe nucleus-derived neural stem cells/progenitors (RN-NSCs) into a complete spinal cord transection lesion site in adult female rats. Grafting embryonic spinal cord-derived NSCs or injury alone served as 2 controls. Ten weeks after injury/grafting, histological analysis revealed well-survived grafts and partial integration with host tissues in the lesion site. Numerous graft-derived serotonergic axons topographically projected to the caudal autonomic regions. Neuronal tracing showed that host supraspinal vasomotor pathways regenerated into the graft, and 5-HT+ neurons within graft and host brainstem neurons were transsynaptically labeled by injecting pseudorabies virus (PRV-614) into the kidney, indicating reconnected serotonergic circuits regulating autonomic activity. Using an implanted telemeter to record cardiovascular parameters, grafting RN-NSCs restored resting mean arterial pressure to normal levels and remarkably alleviated naturally occurring and colorectal distension-induced AD. Subsequent pharmacological blockade of 5-HT2A receptors with ketanserin in RN-NSC-grafted rats reduced resting mean arterial pressure and increased heart rate in all but 2 controls. Furthermore, spinal cord retransection below RN-NSC grafts partially eliminated the recovery in AD. Collectively, these data indicate that RN-NSCs grafted into a spinal cord injury site relay supraspinal control of serotonergic regulation for sympathetic activity to improve cardiovascular function.SIGNIFICANCE STATEMENT Disruption of supraspinal vasomotor pathways results in cardiovascular dysfunction following high-level spinal cord injury. To reestablish the descending regulation of autonomic function, we transplanted serotonergic neuron enriched embryonic raphe nucleus-derived neural stem cells/progenitors into the lesion site of completely transected rat spinal cord. Consequently, grafted raphe nucleus-derived neural stem cells/progenitors acted as a neuronal relay to reconnect supraspinal center and spinal sympathetic neurons below the injury. The reconstituted serotonergic regulation of sympathetic activity led to the improvement of hemodynamic parameters and mitigated autonomic dysreflexia. Based on morphological and physiological results, this study validates the effectiveness of transplanting early-stage serotonergic neurons into the spinal cord for cardiovascular functional recovery after spinal cord injury.
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Attenuating Neurogenic Sympathetic Hyperreflexia Robustly Improves Antibacterial Immunity After Chronic Spinal Cord Injury. J Neurosci 2019; 40:478-492. [PMID: 31754014 DOI: 10.1523/jneurosci.2417-19.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 02/06/2023] Open
Abstract
Spinal cord injury (SCI) disrupts critical physiological systems, including the cardiovascular and immune system. Plasticity of spinal circuits below the injury results in abnormal, heightened sympathetic responses, such as extreme, sudden hypertension that hallmarks life-threatening autonomic dysreflexia. Moreover, such sympathetic hyperreflexia detrimentally impacts other effector organs, including the spleen, resulting in spinal cord injury-induced immunodeficiency. Consequently, infection is a leading cause of mortality after SCI. Unfortunately, there are no current treatments that prophylactically limit sympathetic hyperreflexia to prevent subsequent effector organ dysfunction. The cytokine soluble tumor necrosis factor α (sTNFα) is upregulated in the CNS within minutes after SCI and remains elevated. Here, we report that commencing intrathecal administration of XPro1595, an inhibitor of sTNFα, at a clinically feasible, postinjury time point (i.e., 3 d after complete SCI) sufficiently diminishes maladaptive plasticity within the spinal sympathetic reflex circuit. This results in less severe autonomic dysreflexia, a real-time gauge of sympathetic hyperreflexia, for months postinjury. Remarkably, delayed delivery of the sTNFα inhibitor prevents sympathetic hyperreflexia-associated splenic atrophy and loss of leukocytes to dramatically improve the endogenous ability of chronic SCI rats to fight off pneumonia, a common cause of hospitalization after injury. The improved immune function with XPro1595 correlates with less noradrenergic fiber sprouting and normalized norepinephrine levels in the spleen, indicating that heightened, central sTNFα signaling drives peripheral, norepinephrine-mediated organ dysfunction, a novel mechanism of action. Thus, our preclinical study supports intrathecally targeting sTNFα as a viable strategy to broadly attenuate sympathetic dysregulation, thereby improving cardiovascular regulation and immunity long after SCI.SIGNIFICANCE STATEMENT Spinal cord injury (SCI) significantly disrupts immunity, thus increasing susceptibility to infection, a leading cause of morbidity in those living with SCI. Here, we report that commencing intrathecal administration of an inhibitor of the proinflammatory cytokine soluble tumor necrosis factor α days after an injury sufficiently diminishes autonomic dysreflexia, a real time gauge of sympathetic hyperreflexia, to prevent associated splenic atrophy. This dramatically improves the endogenous ability of chronically injured rats to fight off pneumonia, a common cause of hospitalization. This preclinical study could have a significant impact for broadly improving quality of life of SCI individuals.
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Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats. Neural Plast 2019; 2019:6147878. [PMID: 31827498 PMCID: PMC6885787 DOI: 10.1155/2019/6147878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/30/2019] [Accepted: 09/05/2019] [Indexed: 11/18/2022] Open
Abstract
Electrical stimulations of dorsal cutaneous nerves (DCNs) at each lumbothoracic spinal level produce the bilateral cutaneus trunci muscle (CTM) reflex responses which consist of two temporal components: an early and late responses purportedly mediated by Aδ and C fibers, respectively. We have previously reported central projections of DCN A and C fibers and demonstrated that different projection patterns of those afferent types contributed to the somatotopic organization of CTM reflex responses. Unilateral hemisection spinal cord injury (SCI) was made at T10 spinal segments to investigate the plasticity of early and late CTM responses 6 weeks after injury. Both early and late responses were drastically increased in response to both ipsi- and contralateral DCN stimulations both above (T6 and T8) and below (T12 and L1) the levels of injury demonstrating that nociceptive hyperreflexia developed at 6 weeks following hemisection SCI. We also found that DCN A and C fibers centrally sprouted, expanded their projection areas, and increased synaptic terminations in both T7 and T13, which correlated with the size of hemisection injury. These data demonstrate that central sprouting of cutaneous afferents away from the site of injury is closely associated with enhanced responses of intraspinal signal processing potentially contributing to nociceptive hyperreflexia following SCI.
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Michael FM, Patel SP, Rabchevsky AG. Intraspinal Plasticity Associated With the Development of Autonomic Dysreflexia After Complete Spinal Cord Injury. Front Cell Neurosci 2019; 13:505. [PMID: 31780900 PMCID: PMC6856770 DOI: 10.3389/fncel.2019.00505] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 10/28/2019] [Indexed: 01/02/2023] Open
Abstract
Traumatic spinal cord injury (SCI) leads to disruption of sensory, motor and autonomic function, and triggers structural, physiological and biochemical changes that cause reorganization of existing circuits that affect functional recovery. Propriospinal neurons (PN) appear to be very plastic within the inhibitory microenvironment of the injured spinal cord by forming compensatory circuits that aid in relaying information across the lesion site and, thus, are being investigated for their potential to promote locomotor recovery after experimental SCI. Yet the role of PN plasticity in autonomic dysfunction is not well characterized, notably, the disruption of supraspinal modulatory signals to spinal sympathetic neurons after SCI at the sixth thoracic spinal segment or above resulting in autonomic dysreflexia (AD). This condition is characterized by unmodulated sympathetic reflexes triggering sporadic hypertension associated with baroreflex mediated bradycardia in response to noxious yet unperceived stimuli below the injury to reduce blood pressure. AD is frequently triggered by pelvic visceral distension (bowel and bladder), and there are documented structural relationships between injury-induced sprouting of pelvic visceral afferent C-fibers. Their excitation of lumbosacral PN, in turn, sprout and relay noxious visceral sensory stimuli to rostral disinhibited thoracic sympathetic preganglionic neurons (SPN) that manifest hypertension. Herein, we review evidence for maladaptive plasticity of PN in neural circuits mediating heightened sympathetic reflexes after complete high thoracic SCI that manifest cardiovascular dysfunction, as well as contemporary research methodologies being employed to unveil the precise contribution of PN plasticity to the pathophysiology underlying AD development.
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Affiliation(s)
- Felicia M Michael
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
| | - Samir P Patel
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
| | - Alexander G Rabchevsky
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
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Tibbett JA, Field‐Fote EC, Thomas CK, Widerström‐Noga EG. Spasticity and Pain after Spinal Cord Injury: Impact on Daily Life and the Influence of Psychological Factors. PM R 2019; 12:119-129. [DOI: 10.1002/pmrj.12218] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 06/30/2019] [Indexed: 01/31/2023]
Affiliation(s)
- Jacqueline A. Tibbett
- The Miami Project to Cure Paralysis University of Miami Miami FL
- Department of Physiology and BiophysicsUniversity of Miami Miami FL
| | - Edelle C. Field‐Fote
- Shepherd Center, Crawford Research Institute Atlanta GA
- Division of Physical TherapyEmory University School of Medicine Atlanta GA
| | - Christine K. Thomas
- The Miami Project to Cure Paralysis University of Miami Miami FL
- Department of Physiology and BiophysicsUniversity of Miami Miami FL
- Department of Neurological SurgeryUniversity of Miami Miami FL
| | - Eva G. Widerström‐Noga
- The Miami Project to Cure Paralysis University of Miami Miami FL
- Department of Neurological SurgeryUniversity of Miami Miami FL
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Abstract
Context: Autonomic dysreflexia (AD) is characterized by a sudden onset of hypertension in those with spinal cord injuries (SCI) at T6 or above. Prompt recognition and treatment of AD is important. Herein are two individuals with SCI and acute hypertension due to anxiety that may easily have been confused for AD. Findings: Case 1: A 77-year-old male with C4 AIS D SCI and a history of anxiety and AD presented for urodynamics to evaluate the effectiveness of onabotulinumtoxinA injections into his urethral sphincter. After lying down on the urodynamics table, his systolic blood pressure (SBP) was noted to rise, from 138 to 170 mmHg over six minutes without any instrumentation or position change. Upon announcing urodynamics would be postponed and preparing for AD management, his SBP returned to below baseline within two minutes. Case 2: A 57-year-old male with T12 AIS A SCI and a history of anxiety presented for routine urodynamics. His baseline SBP was 140 mmHg. During bladder filling, incidental SBP was elevated to 170 mmHg. Filling was stopped and he was told the study was complete. One minute later, prior to draining his bladder, SBP decreased to 150 mmHg. Conclusions: An individual's psychological state should be considered in addition to traditional management of AD when an individual with SCI presents with hypertension. Moreover, Case 2 may possibly explain reports of individuals presenting with AD with injuries below T6.
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Affiliation(s)
- Ryan Solinsky
- Spaulding Rehabilitation Hospital, Boston, Massachusetts, USA,Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA,Correspondence to: Ryan Solinsky, Spaulding Rehabilitation Hospital, Harvard Medical School, 300 First Avenue, Boston, MA 02129, USA; Ph: (617) 952-6374. E-mail:
| | - Todd A. Linsenmeyer
- Kessler Institute for Rehabilitation, West Orange, New Jersey, USA,Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA,Department of Surgery, Division of Urology, Rutgers New Jersey Medical School, Newark, New Jersey, USA
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41
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Chariker JH, Gomes C, Brabazon F, Harman KA, Ohri SS, Magnuson DSK, Whittemore SR, Petruska JC, Rouchka EC. Transcriptome of dorsal root ganglia caudal to a spinal cord injury with modulated behavioral activity. Sci Data 2019; 6:83. [PMID: 31175296 PMCID: PMC6555821 DOI: 10.1038/s41597-019-0088-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/29/2019] [Indexed: 12/30/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating clinical condition resulting in significant disabilities. Apart from local injury within the spinal cord, SCI patients develop a myriad of complications including multi-organ dysfunction. Some of the dysfunctions may be directly or indirectly related to the sensory neurons of the dorsal root ganglia (DRG), which signal to both the spinal cord and the peripheral organs. After SCI, some classes of DRG neurons exhibit sensitization and undergo axonal sprouting both peripherally and centrally. Such physiological and anatomical re-organization after SCI contributes to both adaptive and maladaptive plasticity processes, which may be modulated by activity and exercise. In this study, we collected comprehensive gene expression data in whole DRG below the levels of the injury to compare the effects of SCI with and without two different forms of exercise in rats.
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Affiliation(s)
- Julia H Chariker
- Department of Neuroscience Training, University of Louisville, 522 East Gray Street, Louisville, Kentucky, 40202, USA
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, 522 East Gray Street, Louisville, Kentucky, 40202, USA
| | - Cynthia Gomes
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
| | - Fiona Brabazon
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
- Wiley Publishing, Hoboken, NJ, 07030, USA
| | - Kathryn A Harman
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Health & Sport Sciences, University of Louisville, 2100 South Floyd Street, Louisville, KY, 40208, USA
| | - Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
| | - David S K Magnuson
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
| | - Scott R Whittemore
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA
| | - Jeffrey C Petruska
- Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA.
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd St., Louisville, KY, 40202, USA.
- Department of Neurological Surgery, University of Louisville, 220 Abraham Flexner Way, Suite 1500, Louisville, KY, 40202, USA.
| | - Eric C Rouchka
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, 522 East Gray Street, Louisville, Kentucky, 40202, USA.
- Department of Computer Engineering and Computer Science, Speed School of Engineering, University of Louisville, Duthie Center for Engineering, 2301 South 3rd St., Louisville, Kentucky, 40292, USA.
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42
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Harman KA, States G, Wade A, Stepp C, Wainwright G, DeVeau K, King N, Shum-Siu A, Magnuson DSK. Temporal analysis of cardiovascular control and function following incomplete T3 and T10 spinal cord injury in rodents. Physiol Rep 2019; 6:e13634. [PMID: 29595874 PMCID: PMC5875543 DOI: 10.14814/phy2.13634] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/05/2018] [Indexed: 11/24/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that results in whole‐body dysfunction, notably cardiovascular (CV) disruption and disease. Injury‐induced destruction of autonomic pathways in conjunction with a progressive decline in physical fitness contribute to the poor CV status of SCI individuals. Despite the wide use of exercise training as a therapeutic option to reduce CV dysfunction, little is known about the acute hemodynamic responses to the exercise itself. We investigated CV responses to an exercise challenge (swimming) following both high and low thoracic contusion to determine if the CV system is able to respond appropriately to the challenge of swimming. Blood pressure (BP) telemetry and echocardiography were used to track the progression of dysfunction in rodents with T3 and T10 SCI (n = 8 each) for 10 weeks postcontusion. At 1 week postinjury, all animals displayed a drastic decline in heart rate (HR) during the exercise challenge, likely a consequence of neurogenic shock. Furthermore, over time, all groups developed a progressive inability to maintain BP within a narrow range during the exercise challenge despite displaying normal hemodynamic parameters at rest. Echocardiography of T10 animals revealed no persistent signs of cardiac dysfunction; T3 animals exhibited a transient decline in systolic function that returned to preinjury levels by 10 weeks postinjury. Novel evidence provided here illustrates that incomplete injuries produce hemodynamic instability that only becomes apparent during an exercise challenge. Further, this dysfunction lasts into the chronic phase of disease progression despite significant recovery of hindlimb locomotion and cardiac function.
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Affiliation(s)
- Kathryn A Harman
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - Gregory States
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - Abigail Wade
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky.,Biomedical Engineering, University of Louisville, Louisville, Kentucky
| | - Chad Stepp
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky.,Biomedical Engineering, University of Louisville, Louisville, Kentucky
| | - Grace Wainwright
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky.,Biomedical Engineering, University of Louisville, Louisville, Kentucky
| | - Kathryn DeVeau
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - Nicholas King
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky.,Biomedical Engineering, University of Louisville, Louisville, Kentucky
| | - Alice Shum-Siu
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - David S K Magnuson
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky.,Biomedical Engineering, University of Louisville, Louisville, Kentucky
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43
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Squair JW, Ruiz I, Phillips AA, Zheng MM, Sarafis ZK, Sachdeva R, Gopaul R, Liu J, Tetzlaff W, West CR, Krassioukov AV. Minocycline Reduces the Severity of Autonomic Dysreflexia after Experimental Spinal Cord Injury. J Neurotrauma 2018; 35:2861-2871. [DOI: 10.1089/neu.2018.5703] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Jordan W. Squair
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- MD/PhD Training Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ian Ruiz
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aaron A. Phillips
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mei M.Z. Zheng
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zoe K. Sarafis
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rahul Sachdeva
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rayshad Gopaul
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, Faculty of Science, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher R. West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrei V. Krassioukov
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, British Columbia, Canada
- GF Strong Rehabilitation Centre, Vancouver Health Authority, Vancouver, British Columbia, Canada
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44
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Sliwinski C, Nees TA, Puttagunta R, Weidner N, Blesch A. Sensorimotor Activity Partially Ameliorates Pain and Reduces Nociceptive Fiber Density in the Chronically Injured Spinal Cord. J Neurotrauma 2018; 35:2222-2238. [PMID: 29706124 DOI: 10.1089/neu.2017.5431] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A large proportion of patients suffering from spinal cord injury (SCI) develop chronic central neuropathic pain. Previously, we and others have shown that sensorimotor training early after SCI can prevent the development of mechanical allodynia. To determine whether training initiated in the subchronic/chronic phase remains effective, correlates of below-level neuropathic pain were analyzed in the hindpaws 5-10 weeks after a moderate T11 contusion SCI (50 kDyn) in adult female C57BL/6 mice. In a comparison of SCI and sham mice 5 weeks post-injury, about 80% of injured animals developed mechanical hypersensitivity to light mechanical stimuli, whereas testing of noxious stimuli revealed hypo-responsiveness. Thermal sensitivity testing showed a decreased response latency after injury. Without intervention, mechanical and thermal hyper-responsiveness were evident until the end of the experiment (10 weeks). In contrast, treadmill training (2 × 15 min/day; 5 × /week) initiated 6 weeks post-injury resulted in partial amelioration of pain behavior and this effect remained stable. Analysis of calcitonin gene-related peptide (CGRP)-labeled fibers in lamina III-IV of the lumbar dorsal horn revealed an increase in labeling density after SCI. This was not due to changes in the number or size distribution of CGRP-labeled lumbar dorsal root ganglion neurons. Treadmill training reduced the CGRP-labeling density in the spinal cord of injured mice, whereas the density of non-peptidergic isolectin-B4 (IB4)+ fibers showed no changes in lamina IIi and a slight reduction of sparse IB4 labeling in laminae III-IV. Thus, sensorimotor activity initiated in the subchronic/chronic phase of SCI remains effective in ameliorating pain behavior and influencing structural changes of the nociceptive system.
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Affiliation(s)
| | - Timo A Nees
- 1 Spinal Cord Injury Center, Heidelberg University Hospital , Heidelberg, Germany .,2 Center for Orthopedic and Trauma Surgery, Heidelberg University Hospital , Heidelberg, Germany
| | - Radhika Puttagunta
- 1 Spinal Cord Injury Center, Heidelberg University Hospital , Heidelberg, Germany
| | - Norbert Weidner
- 1 Spinal Cord Injury Center, Heidelberg University Hospital , Heidelberg, Germany
| | - Armin Blesch
- 1 Spinal Cord Injury Center, Heidelberg University Hospital , Heidelberg, Germany .,3 Department of Neurological Surgery and Goodman Campbell Brain and Spine, Stark Neurosciences Research Institute, Indiana University School of Medicine , Indianapolis, Indiana
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45
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Takiguchi M, Fujioka M, Funakoshi K. Neonatal spinal injury induces de novo projections of primary afferents to the lumbosacral intermediolateral nucleus in rats. IBRO Rep 2018; 4:1-6. [PMID: 30135945 PMCID: PMC6084831 DOI: 10.1016/j.ibror.2017.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 11/24/2017] [Accepted: 11/28/2017] [Indexed: 11/15/2022] Open
Abstract
Neonatal spinal injury induces dextran amine-labeled primary afferent projections to the sacral intermediolateral nucleus. Dextran amine-labeled afferent fibers form varicose terminals on the parasympathetic preganglionic neurons. Dextran amine tends to be incorporated preferentially in dorsal root ganglion neurons with myelinated fibers. De novo projections of myelinated afferents might contribute to the recovery of micturition following neonatal spinal injury.
Complete spinal transection in adult rats results in poor recovery of hind limb function and severe urinary bladder dysfunction. Neonatal rats with spinal cord transection, however, exhibit spontaneous and significant recovery of micturition control. A previous study in which biotinylated-dextran amine (BDA) was used as an anterograde tracer demonstrated that primary afferent fibers from the fifth lumbar dorsal root ganglion (DRG) project more strongly and make more terminals in the ventral horn after neonatal spinal cord transection at the mid-thoracic level. In the present study, we injected BDA into the sixth lumbar (L6) DRG of neonatally spinalized rats to label primary afferent fibers that include visceral afferents. The labeled fibers projected to the intermediolateral nucleus (IML) in the intermediate zone on ipsilateral side of the L6 spinal segment, whereas no projections to the IML were observed in sham-operated or intact rats. The BDA-labeled fibers of neonatally spinalized rats formed varicose terminals on parasympathetic preganglionic neurons in the IML. These findings suggest that some primary afferent projections from the L6 DRG to the IML appear after neonatal spinal cord transection, and these de novo projections might contribute to the recovery of autonomic function such as micturition following spinal cord injury in the neonatal stage.
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46
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Soluble TNFα Signaling within the Spinal Cord Contributes to the Development of Autonomic Dysreflexia and Ensuing Vascular and Immune Dysfunction after Spinal Cord Injury. J Neurosci 2018; 38:4146-4162. [PMID: 29610439 DOI: 10.1523/jneurosci.2376-17.2018] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 03/08/2018] [Accepted: 03/14/2018] [Indexed: 12/15/2022] Open
Abstract
Cardiovascular disease and susceptibility to infection are leading causes of morbidity and mortality for individuals with spinal cord injury (SCI). A major contributor to these is autonomic dysreflexia (AD), an amplified reaction of the autonomic nervous system (hallmarked by severe hypertension) in response to sensory stimuli below the injury. Maladaptive plasticity of the spinal sympathetic reflex circuit below the SCI results in AD intensification over time. Mechanisms underlying this maladaptive plasticity are poorly understood, restricting the identification of treatments. Thus, no preventative treatments are currently available. Neuroinflammation has been implicated in other pathologies associated with hyperexcitable neural circuits. Specifically, the soluble form of TNFα (sTNFα) is known to play a role in neuroplasticity. We hypothesize that persistent expression of sTNFα in spinal cord underlies AD exacerbation. To test this, we intrathecally administered XPro1595, a biologic that renders sTNFα nonfunctional, after complete, high-level SCI in female rats. This dramatically attenuated the intensification of colorectal distension-induced and naturally occurring AD events. This improvement is mediated via decreased sprouting of nociceptive primary afferents and activation of the spinal sympathetic reflex circuit. We also examined peripheral vascular function using ex vivo pressurized arterial preparations and immune function via flow cytometric analysis of splenocytes. Diminishing AD via pharmacological inhibition of sTNFα mitigated ensuing vascular hypersensitivity and immune dysfunction. This is the first demonstration that neuroinflammation-induced sTNFα is critical for altering the spinal sympathetic reflex circuit, elucidating a novel mechanism for AD. Importantly, we identify the first potential pharmacological, prophylactic treatment for this life-threatening syndrome.SIGNIFICANCE STATEMENT Autonomic dysreflexia (AD), a disorder that develops after spinal cord injury (SCI) and is hallmarked by sudden, extreme hypertension, contributes to cardiovascular disease and susceptibility to infection, respectively, two leading causes of mortality and morbidity in SCI patients. We demonstrate that neuroinflammation-induced expression of soluble TNFα plays a critical role in AD, elucidating a novel underlying mechanism. We found that intrathecal administration after SCI of a biologic that inhibits soluble TNFα signaling dramatically attenuates AD and significantly reduces AD-associated peripheral vascular and immune dysfunction. We identified mechanisms behind diminished plasticity of neuronal populations within the spinal sympathetic reflex circuit. This study is the first to pinpoint a potential pharmacological, prophylactic strategy to attenuate AD and ensuing cardiovascular and immune dysfunction.
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47
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Descending Systems Direct Development of Key Spinal Motor Circuits. J Neurosci 2017; 37:6372-6387. [PMID: 28576940 DOI: 10.1523/jneurosci.0149-17.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/10/2017] [Accepted: 05/24/2017] [Indexed: 12/17/2022] Open
Abstract
The formation of mature spinal motor circuits is dependent on both activity-dependent and independent mechanisms during postnatal development. During this time, reorganization and refinement of spinal sensorimotor circuits occurs as supraspinal projections are integrated. However, specific features of postnatal spinal circuit development remain poorly understood. This study provides the first detailed characterization of rat spinal sensorimotor circuit development in the presence and absence of descending systems. We show that the development of proprioceptive afferent input to motoneurons (MNs) and Renshaw cells (RCs) is disrupted by thoracic spinal cord transection at postnatal day 5 (P5TX). P5TX also led to malformation of GABApre neuron axo-axonic contacts on Ia afferents and of the recurrent inhibitory circuit between MNs and RCs. Using a novel in situ perfused preparation for studying motor control, we show that malformation of these spinal circuits leads to hyperexcitability of the monosynaptic reflex. Our results demonstrate that removing descending input severely disrupts the development of spinal circuits and identifies key mechanisms contributing to motor dysfunction in conditions such as cerebral palsy and spinal cord injury.SIGNIFICANCE STATEMENT Acquisition of mature behavior during postnatal development correlates with the arrival and maturation of supraspinal projections to the spinal cord. However, we know little about the role that descending systems play in the maturation of spinal circuits. Here, we characterize postnatal development of key spinal microcircuits in the presence and absence of descending systems. We show that formation of these circuits is abnormal after early (postnatal day 5) removal of descending systems, inducing hyperexcitability of the monosynaptic reflex. The study is a detailed characterization of spinal circuit development elucidating how these mechanisms contribute to motor dysfunction in conditions such as cerebral palsy and spinal cord injury. Understanding these circuits is crucial to developing new therapeutics and improving existing ones in such conditions.
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48
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Eldahan KC, Rabchevsky AG. Autonomic dysreflexia after spinal cord injury: Systemic pathophysiology and methods of management. Auton Neurosci 2017; 209:59-70. [PMID: 28506502 DOI: 10.1016/j.autneu.2017.05.002] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 03/30/2017] [Accepted: 05/03/2017] [Indexed: 12/11/2022]
Abstract
Traumatic spinal cord injury (SCI) has widespread physiological effects beyond the disruption of sensory and motor function, notably the loss of normal autonomic and cardiovascular control. Injury at or above the sixth thoracic spinal cord segment segregates critical spinal sympathetic neurons from supraspinal modulation which can result in a syndrome known as autonomic dysreflexia (AD). AD is defined as episodic hypertension and concomitant baroreflex-mediated bradycardia initiated by unmodulated sympathetic reflexes in the decentralized cord. This condition is often triggered by noxious yet unperceived visceral or somatic stimuli below the injury level and if severe enough can require immediate medical attention. Herein, we review the pathophysiological mechanisms germane to the development of AD, including maladaptive plasticity of neural circuits mediating abnormal sympathetic reflexes and hypersensitization of peripheral vasculature that collectively contribute to abnormal hemodynamics after SCI. Further, we discuss the systemic effects of recurrent AD and pharmacological treatments used to manage such episodes. Contemporary research avenues are then presented to better understand the relative contributions of underlying mechanisms and to elucidate the effects of recurring AD on cardiovascular and immune functions for developing more targeted and effective treatments to attenuate the development of this insidious syndrome following high-level SCI.
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Affiliation(s)
- Khalid C Eldahan
- Department of Physiology, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States
| | - Alexander G Rabchevsky
- Department of Physiology, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States.
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49
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Bellardita C, Caggiano V, Leiras R, Caldeira V, Fuchs A, Bouvier J, Löw P, Kiehn O. Spatiotemporal correlation of spinal network dynamics underlying spasms in chronic spinalized mice. eLife 2017; 6:23011. [PMID: 28191872 PMCID: PMC5332159 DOI: 10.7554/elife.23011] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 01/27/2017] [Indexed: 12/28/2022] Open
Abstract
Spasms after spinal cord injury (SCI) are debilitating involuntary muscle contractions that have been associated with increased motor neuron excitability and decreased inhibition. However, whether spasms involve activation of premotor spinal excitatory neuronal circuits is unknown. Here we use mouse genetics, electrophysiology, imaging and optogenetics to directly target major classes of spinal interneurons as well as motor neurons during spasms in a mouse model of chronic SCI. We find that assemblies of excitatory spinal interneurons are recruited by sensory input into functional circuits to generate persistent neural activity, which interacts with both the graded expression of plateau potentials in motor neurons to generate spasms, and inhibitory interneurons to curtail them. Our study reveals hitherto unrecognized neuronal mechanisms for the generation of persistent neural activity under pathophysiological conditions, opening up new targets for treatment of muscle spasms after SCI. DOI:http://dx.doi.org/10.7554/eLife.23011.001
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Affiliation(s)
- Carmelo Bellardita
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Vittorio Caggiano
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Roberto Leiras
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Vanessa Caldeira
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Andrea Fuchs
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Julien Bouvier
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Peter Löw
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ole Kiehn
- Mammalian locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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50
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Squair JW, West CR, Popok D, Assinck P, Liu J, Tetzlaff W, Krassioukov AV. High Thoracic Contusion Model for the Investigation of Cardiovascular Function after Spinal Cord Injury. J Neurotrauma 2017; 34:671-684. [DOI: 10.1089/neu.2016.4518] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Jordan W. Squair
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- MD/PhD Training Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher R. West
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David Popok
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Peggy Assinck
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, Faculty of Science, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrei V. Krassioukov
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, British Columbia, Canada
- GF Strong Rehabilitation Centre, Vancouver Health Authority, Vancouver, British Columbia, Canada
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