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Baroudi M, Rezk A, Daher M, Balmaceno-Criss M, Gregoryczyk JG, Sharma Y, McDonald CL, Diebo BG, Daniels AH. Management of traumatic spinal cord injury: A current concepts review of contemporary and future treatment. Injury 2024; 55:111472. [PMID: 38460480 DOI: 10.1016/j.injury.2024.111472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 02/03/2024] [Accepted: 02/25/2024] [Indexed: 03/11/2024]
Abstract
Spinal Cord Injury (SCI) is a condition leading to inflammation, edema, and dysfunction of the spinal cord, most commonly due to trauma, tumor, infection, or vascular disturbance. Symptoms include sensory and motor loss starting at the level of injury; the extent of damage depends on injury severity as detailed in the ASIA score. In the acute setting, maintaining mean arterial pressure (MAP) higher than 85 mmHg for up to 7 days following injury is preferred; although caution must be exercised when using vasopressors such as phenylephrine due to serious side effects such as pulmonary edema and death. Decompression surgery (DS) may theoretically relieve edema and reduce intraspinal pressure, although timing of surgery remains a matter of debate. Methylprednisolone (MP) is currently used due to its ability to reduce inflammation but more recent studies question its clinical benefits, especially with inconsistency in recommending it nationally and internationally. The choice of MP is further complicated by conflicting evidence for optimal timing to initiate treatment, and by the reported observation that higher doses are correlated with increased risk of complications. Thyrotropin-releasing hormone may be beneficial in less severe injuries. Finally, this review discusses many options currently being researched and have shown promising pre-clinical results.
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Affiliation(s)
- Makeen Baroudi
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Anna Rezk
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Mohammad Daher
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Mariah Balmaceno-Criss
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Jerzy George Gregoryczyk
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Yatharth Sharma
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Christopher L McDonald
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Bassel G Diebo
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Alan H Daniels
- Department of Orthopedic Surgery, The Warren Alpert Medical School of Brown University, Providence, RI, USA.
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Witkin JM, Radin DP, Rana S, Fuller DD, Fusco AF, Demers JC, Pradeep Thakre P, Smith JL, Lippa A, Cerne R. AMPA receptors play an important role in the biological consequences of spinal cord injury: Implications for AMPA receptor modulators for therapeutic benefit. Biochem Pharmacol 2024:116302. [PMID: 38763261 DOI: 10.1016/j.bcp.2024.116302] [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: 03/04/2024] [Revised: 05/07/2024] [Accepted: 05/16/2024] [Indexed: 05/21/2024]
Abstract
Spinal cord injury (SCI) afflicts millions of individuals globally. There are few therapies available to patients. Ascending and descending excitatory glutamatergic neural circuits in the central nervous system are disrupted by SCI, making α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) a potential therapeutic drug target. Emerging research in preclinical models highlights the involvement of AMPARs in vital processes following SCI including breathing, pain, inflammation, bladder control, and motor function. However, there are no clinical trial data reported in this patient population to date. No work on the role of AMPA receptors in sexual dysfunction after SCI has been disclosed. Compounds with selective antagonist and potentiating effects on AMPA receptors have benefit in animal models of SCI, with antagonists generally showing protective effects early after injury and potentiators (ampakines) producing improved breathing and bladder function. The role of AMPARs in pathophysiology and recovery after SCI depends upon the time post injury, and the timing of AMPAR augmentation or antagonism. The roles of inflammation, synaptic plasticity, sensitization, neurotrophic factors, and neuroprotection are considered in this context. The data summarized and discussed in this paper document proof of principle and strongly encourage additional studies on AMPARs as novel gateways to therapeutic benefit for patients suffering from SCI. The availability of both AMPAR antagonists such as perampanel and AMPAR allosteric modulators (i.e., ampakines) such as CX1739, that have been safely administered to humans, provides an expedited means of clinical inquiry for possible therapeutic advances.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; Departments of Neuroscience and Trauma Research, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA.
| | | | - Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Anna F Fusco
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Julie C Demers
- Indiana University/Purdue University, Indianapolis, IN, USA
| | - Prajwal Pradeep Thakre
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA
| | - Arnold Lippa
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA
| | - Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA; Faculty of Medicine, University of Ljubljana, Zaloška Cesta 4, Ljubljana, Slovenia
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3
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Fogarty MJ, Zhan WZ, Mantilla CB, Sieck GC. Cervical spinal cord hemisection impacts sigh and the respiratory reset in male rats. Physiol Rep 2024; 12:e15973. [PMID: 38467570 DOI: 10.14814/phy2.15973] [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: 10/05/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/13/2024] Open
Abstract
Cervical spinal cord injury impacts ventilatory and non-ventilatory functions of the diaphragm muscle (DIAm) and contributes to clinical morbidity and mortality in the afflicted population. Periodically, integrated brainstem neural circuit activity drives the DIAm to generate a markedly augmented effort or sigh-which plays an important role in preventing atelectasis and thus maintaining lung function. Across species, the general pattern of DIAm efforts during a normal sigh is variable in amplitude and the extent of post-sigh "apnea" (i.e., the post-sigh inter-breath interval). This post-sigh inter-breath interval acts as a respiratory reset, following the interruption of regular respiratory rhythm by sigh. We examined the impact of upper cervical (C2 ) spinal cord hemisection (C2 SH) on the transdiaphragmatic pressure (Pdi ) generated during sighs and the post-sigh respiratory reset in rats. Sighs were identified in Pdi traces by their characteristic biphasic pattern. We found that C2 SH results in a reduction of Pdi during both eupnea and sighs, and a decrease in the immediate post-sigh breath interval. These results are consistent with partial removal of descending excitatory synaptic inputs to phrenic motor neurons that results from C2 SH. Following cervical spinal cord injury, a reduction in the amplitude of Pdi during sighs may compromise the maintenance of normal lung function.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Wen-Zhi Zhan
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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Silverstein AL, Lawson KG, Farhadi HF, Alilain WJ. Contrasting Experimental Rodent Aftercare With Human Clinical Treatment for Cervical Spinal Cord Injury: Bridging the Translational "Valley of Death". J Neurotrauma 2023; 40:2469-2486. [PMID: 37772694 PMCID: PMC10698787 DOI: 10.1089/neu.2023.0314] [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: 09/30/2023] Open
Abstract
More than half of all spinal cord injuries (SCIs) occur at the cervical level and often lead to life-threatening breathing motor dysfunction. The C2 hemisection (C2Hx) and high cervical contusion mouse and rat models of SCI are widely utilized both to understand the pathological effects of SCI and to develop potential therapies. Despite rigorous research effort, pre-clinical therapeutics studied in those animal models of SCI sometimes fail when evaluated in the clinical setting. Differences between standard-of-care treatment for acute SCI administered to clinical populations and experimental animal models of SCI could influence the heterogeneity of outcome between pre-clinical and clinical studies. In this review, we have summarized both the standard clinical interventions used to treat patients with cervical SCI and the various veterinary aftercare protocols used to care for rats and mice after experimentally induced C2Hx and high cervical contusion models of SCI. Through this analysis, we have identified areas of marked dissimilarity between clinical and veterinary protocols and suggest the modification of pre-clinical animal care particularly with respect to analgesia, anticoagulative measures, and stress ulcer prophylaxis. In our discussion, we intend to inspire consideration of potential changes to aftercare for animal subjects of experimental SCI that may help to bridge the translational "Valley of Death" and ultimately contribute more effectively to finding treatments capable of restoring independent breathing function to persons with cervical SCI.
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Affiliation(s)
- Aaron L. Silverstein
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Katelyn G. Lawson
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - H. Francis Farhadi
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
- Department of Neurosurgery, Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Warren J. Alilain
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
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Khurram OU, Mantilla CB, Sieck GC. Neuromotor control of spontaneous quiet breathing in awake rats evaluated by assessments of diaphragm EMG stationarity. J Neurophysiol 2023; 130:1344-1357. [PMID: 37877195 DOI: 10.1152/jn.00267.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/23/2023] [Accepted: 10/23/2023] [Indexed: 10/26/2023] Open
Abstract
The neuromotor control of the diaphragm muscle (DIAm) is dynamic. The activity of the DIAm can be recorded via electromyography (EMG), which represents the temporal summation of motor unit action potentials. Our goal in the present study was to investigate DIAm neuromotor control during quiet spontaneous breathing (eupnea) in awake rats by evaluating DIAm EMG at specific temporal locations defined by motor unit recruitment and derecruitment. We evaluated the nonstationarity of DIAm EMG activity to identify DIAm motor unit recruitment and derecruitment durations. Combined with assessments of root mean square (RMS) and sum of squares (SS) EMG, the durations of these phases provide physiological information about the temporal aspects of motor control. During eupnea in awake rats (n = 10), the duration of motor unit recruitment comprised 61 ± 19 ms of the onset-to-peak duration (214 ± 62 ms) of the DIAm RMS EMG. The peak-to-offset duration of DIAm EMG activity was 453 ± 96 ms, with a terminating period of derecruitment of 161 ± 44 ms. The burst duration was 673 ± 128 ms. Both the RMS EMG amplitude and the SS EMG were higher at the completion of motor unit recruitment than at the start of motor unit derecruitment, suggesting that offset discharge rates were lower than onset discharge rates. Our analyses provide novel insights into the time domain aspects of DIAm neuromotor control and allow indirect estimates of the contribution of recruitment and frequency to RMS EMG amplitude during eupnea in awake rats.NEW & NOTEWORTHY We characterized three phases of neuromotor control-motor unit recruitment, sustained activity, and derecruitment-based on statistical assessments of stationarity of the diaphragm muscle (DIAm) EMG activity in awake rats. Our findings may allow indirect estimates of the contribution of motor unit recruitment and frequency coding toward generating force and provide novel insights about the temporal aspects of DIAm neuromotor control and descending respiratory drive in unanesthetized animals.
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Affiliation(s)
- Obaid U Khurram
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Gary C Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
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Hu X, Xu W, Ren Y, Wang Z, He X, Huang R, Ma B, Zhao J, Zhu R, Cheng L. Spinal cord injury: molecular mechanisms and therapeutic interventions. Signal Transduct Target Ther 2023; 8:245. [PMID: 37357239 DOI: 10.1038/s41392-023-01477-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/22/2023] [Accepted: 05/07/2023] [Indexed: 06/27/2023] Open
Abstract
Spinal cord injury (SCI) remains a severe condition with an extremely high disability rate. The challenges of SCI repair include its complex pathological mechanisms and the difficulties of neural regeneration in the central nervous system. In the past few decades, researchers have attempted to completely elucidate the pathological mechanism of SCI and identify effective strategies to promote axon regeneration and neural circuit remodeling, but the results have not been ideal. Recently, new pathological mechanisms of SCI, especially the interactions between immune and neural cell responses, have been revealed by single-cell sequencing and spatial transcriptome analysis. With the development of bioactive materials and stem cells, more attention has been focused on forming intermediate neural networks to promote neural regeneration and neural circuit reconstruction than on promoting axonal regeneration in the corticospinal tract. Furthermore, technologies to control physical parameters such as electricity, magnetism and ultrasound have been constantly innovated and applied in neural cell fate regulation. Among these advanced novel strategies and technologies, stem cell therapy, biomaterial transplantation, and electromagnetic stimulation have entered into the stage of clinical trials, and some of them have already been applied in clinical treatment. In this review, we outline the overall epidemiology and pathophysiology of SCI, expound on the latest research progress related to neural regeneration and circuit reconstruction in detail, and propose future directions for SCI repair and clinical applications.
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Affiliation(s)
- Xiao Hu
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Wei Xu
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Yilong Ren
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Zhaojie Wang
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Xiaolie He
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Runzhi Huang
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Bei Ma
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Jingwei Zhao
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China
| | - Rongrong Zhu
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China.
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China.
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China.
| | - Liming Cheng
- Division of Spine, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, 200065, Shanghai, China.
- Key Laboratory of Spine and Spinal cord Injury Repair and Regeneration (Tongji University), Ministry of Education, 200065, Shanghai, China.
- Clinical Center For Brain And Spinal Cord Research, Tongji University, 200065, Shanghai, China.
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Fogarty MJ, Zhan WZ, Simmon VF, Vanderklish PW, Sarraf ST, Sieck GC. Novel regenerative drug, SPG302 promotes functional recovery of diaphragm muscle activity after cervical spinal cord injury. J Physiol 2023; 601:2513-2532. [PMID: 36815402 PMCID: PMC10404468 DOI: 10.1113/jp284004] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Spinal cord hemisection at C2 (C2 SH), sparing the dorsal column is widely used to investigate the effects of reduced phrenic motor neuron (PhMN) activation on diaphragm muscle (DIAm) function, with reduced DIAm activity on the injured side during eupnoea. Following C2 SH, recovery of DIAm EMG activity may occur spontaneously over subsequent days/weeks. Various strategies have been effective at improving the incidence and magnitude of DIAm recovery during eupnoea, but little is known about the effects of C2 SH on transdiaphragmatic pressure (Pdi ) during other ventilatory and non-ventilatory behaviours. We employ SPG302, a novel type of pegylated benzothiazole derivative, to assess whether enhancing synaptogenesis (i.e., enhancing spared local connections) will improve the incidence and the magnitude of recovery of DIAm EMG activity and Pdi function 14 days post-C2 SH. In anaesthetised Sprague-Dawley rats, DIAm EMG and Pdi were assessed during eupnoea, hypoxia/hypercapnia and airway occlusion prior to surgery (C2 SH or sham), immediately post-surgery and at 14 days post-surgery. In C2 SH rats, 14 days of DMSO (vehicle) or SPG302 treatments (i.p. injection) occurred. At the terminal experiment, maximum Pdi was evoked by bilateral phrenic nerve stimulation. We show that significant EMG and Pdi deficits are apparent in C2 SH compared with sham rats immediately after surgery. In C2 SH rats treated with SPG302, recovery of eupneic, hypoxia/hypercapnia and occlusion DIAm EMG was enhanced compared with vehicle rats after 14 days. Treatment with SPG302 also ameliorated Pdi deficits following C2 SH. In summary, SPG302 is an exciting new therapy to explore for use in spinal cord injuries. KEY POINTS: Despite advances in our understanding of the effects of cervical hemisection (C2 SH) on diaphragm muscle (DIAm) EMG activity, very little is understood about the impact of C2 SH on the gamut of ventilatory and non-ventilatory transdiaphragmatic pressures (Pdi ). Recovery of DIAm activity following C2 SH is improved using a variety of approaches, but very few pharmaceuticals have been shown to be effective. One way of improving DIAm recovery is to enhance the amount of latent local spared connections onto phrenic motor neurons. A novel pegylated benzothiazole derivative enhances synaptogenesis in a variety of neurodegenerative conditions. Here, using a novel therapeutic SPG302, we show that 14 days of treatment with SPG302 ameliorated DIAm EMG and Pdi deficits compared with vehicle controls. Our results show that SPG302 is a compound with very promising potential for use in improving functional outcomes post-spinal cord injury.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Wen-Zhi Zhan
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Vincent F. Simmon
- Spinogenix Inc, 4225 Executive Square, Suite 600 La Jolla, California, USA
| | | | - Stella T. Sarraf
- Spinogenix Inc, 4225 Executive Square, Suite 600 La Jolla, California, USA
| | - Gary C. Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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Fogarty MJ, Dasgupta D, Khurram OU, Sieck GC. Chemogenetic inhibition of TrkB signalling reduces phrenic motor neuron survival and size. Mol Cell Neurosci 2023; 125:103847. [PMID: 36958643 PMCID: PMC10247511 DOI: 10.1016/j.mcn.2023.103847] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 03/07/2023] [Accepted: 03/16/2023] [Indexed: 03/25/2023] Open
Abstract
Brain derived neurotrophic factor (BDNF) signalling through its high-affinity tropomyosin receptor kinase B (TrkB) is known to have potent effects on motor neuron survival and morphology during development and in neurodegenerative diseases. Here, we employed a novel 1NMPP1 sensitive TrkBF616 rat model to evaluate the effect of 14 days inhibition of TrkB signalling on phrenic motor neurons (PhMNs). Adult female and male TrkBF616 rats were divided into 1NMPP1 or vehicle treated groups. Three days prior to treatment, PhMNs in both groups were initially labeled via intrapleural injection of Alexa-Fluor-647 cholera toxin B (CTB). After 11 days of treatment, retrograde axonal uptake/transport was assessed by secondary labeling of PhMNs by intrapleural injection of Alexa-Fluor-488 CTB. After 14 days of treatment, the spinal cord was excised 100 μm thick spinal sections containing PhMNs were imaged using two-channel confocal microscopy. TrkB inhibition reduced the total number of PhMNs by ∼16 %, reduced the mean PhMN somal surface areas by ∼25 %, impaired CTB uptake 2.5-fold and reduced the estimated PhMN dendritic surface area by ∼38 %. We conclude that inhibition of TrkB signalling alone in adult TrkBF616 rats is sufficient to lead to PhMN loss, morphological degeneration and deficits in retrograde axonal uptake/transport.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Debanjali Dasgupta
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Obaid U Khurram
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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9
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Yin F, Liu Z, Zhang D, Shen Z, Niu Z, Guo L. Identification of key genes involved in neural regeneration and the repairing effect of BDNF-overexpressed BMSCs on spinal cord ischemia-reperfusion injury in rats. Biomed Pharmacother 2023; 160:114293. [PMID: 36736275 DOI: 10.1016/j.biopha.2023.114293] [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: 12/05/2022] [Revised: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
Bone marrow mesenchymal stem cells (BMSCs) can repair spinal cord ischemia-reperfusion injury (SCII); however, only a few BMSCs are usually located in the injured spinal cord. Since the brain-derived neurotrophic factor (BDNF) can promote neural development and maturation, we hypothesised that BDNF-overexpressed BMSCs can ameliorate SCII more effectively than BMSCs alone. To determine the effect of BDNF overexpression on SCII repair, BDNF-overexpressed BMSCs and BMSCs were transplanted into SCII rats. Our results revealed that BDNF-overexpressed BMSCs can better promote the recovery of damaged spinal cords than BMSCs alone. Gene chip detection of spinal cord tissues showed 803 differentially expressed genes in all groups. BTG anti-proliferation factor 2 (Btg2), FOS like 2 (Fosl2), early growth response protein 1 (Egr1), and serpin family E member 1 (Serpine1) were identified as key interrelated genes based on their expression trends, as validated via quantitative PCR and protein-protein interaction network analysis. A co-expression network was constructed to further explore the role of the candidate key genes using Pearson correlation analysis. Cluster 5 was identified as the key cluster using community discovery algorithms. Functional analysis of Cluster 5 genes revealed that this cluster was mainly involved in the stress-activated MAPK cascade, p38MAPK cascade, and apoptosis. Notably, Egr1 may play an important role in SCII repair as the top hub gene in Cluster 5. Therefore, the repair activity of transplanted BDNF-overexpressed BMSCs in SCII rats is better than that of BMSCs alone, which may be regulated by the interactions between Btg2, Fosl2, Egr1, Serpine1, and BDNF.
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Affiliation(s)
- Fei Yin
- Department of Spine Surgery, China-Japan Union Hospital of Jilin University, NO.126 Xiantai Street, Changchun, Jilin 130033, China
| | - Zhiming Liu
- Department of Spine Surgery, China-Japan Union Hospital of Jilin University, NO.126 Xiantai Street, Changchun, Jilin 130033, China
| | - Ding Zhang
- Department of Spine Surgery, China-Japan Union Hospital of Jilin University, NO.126 Xiantai Street, Changchun, Jilin 130033, China
| | - Zhubin Shen
- Department of Spine Surgery, China-Japan Union Hospital of Jilin University, NO.126 Xiantai Street, Changchun, Jilin 130033, China
| | - Zefeng Niu
- Department of Spine Surgery, China-Japan Union Hospital of Jilin University, NO.126 Xiantai Street, Changchun, Jilin 130033, China
| | - Li Guo
- Department of Toxicology, School of Public Health, Jilin University, NO.1163 Xinmin Street, Changchun, Jilin 130021, China.
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10
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Hachem LD, Hong J, Velumian A, Mothe AJ, Tator CH, Fehlings MG. Excitotoxic glutamate levels drive spinal cord ependymal stem cell proliferation and fate specification through CP-AMPAR signaling. Stem Cell Reports 2023; 18:672-687. [PMID: 36764296 PMCID: PMC10031285 DOI: 10.1016/j.stemcr.2023.01.005] [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: 05/06/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 02/11/2023] Open
Abstract
The adult spinal cord contains a population of ependymal-derived neural stem/progenitor cells (epNSPCs) that are normally quiescent, but are activated to proliferate, differentiate, and migrate after spinal cord injury. The mechanisms that regulate their response to injury cues, however, remain unknown. Here, we demonstrate that excitotoxic levels of glutamate promote the proliferation and astrocytic fate specification of adult spinal cord epNSPCs. We show that glutamate-mediated calcium influx through calcium-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (CP-AMPARs) in concert with Notch signaling increases the proliferation of epNSPCs via pCREB, and induces astrocytic differentiation through Hes1 upregulation. Furthermore, the in vivo targeting of this pathway via positive modulation of AMPARs after spinal cord injury enhances epNSPC proliferation, astrogliogenesis, neurotrophic factor production and increases neuronal survival. Our study uncovers an important mechanism by which CP-AMPARs regulate the growth and phenotype of epNSPCs, which can be targeted therapeutically to harness the regenerative potential of these cells after injury.
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Affiliation(s)
- Laureen D Hachem
- Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - James Hong
- Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Alexander Velumian
- Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - Andrea J Mothe
- Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Charles H Tator
- Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON M5T 2S8, Canada.
| | - Michael G Fehlings
- Krembil Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON M5T 2S8, Canada.
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11
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Abdanipour A, Mirzaei M, Anarkooli IJ, Mohammadi P. Effect of selegiline as a monomine oxidase B inhibitor on the expression of neurotrophin mRNA levels in a contusion rat model of spinal cord injury. Neurol Res 2023; 45:241-247. [PMID: 36453689 DOI: 10.1080/01616412.2022.2129761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
OBJECTIVE Spinal cord injury (SCI) is followed by a cascade of events at the site of injury, including vascular ischemia, an increase in free radicals, inflammation, and neuronal death. In these individuals, protection of nerves and supporting cells, as well as prevention of neuronal damage, may improve recovery opportunities. Neurotrophins are a family of polypeptides that regulate nerve differentiation, growth, and survival. Selegiline is a selective monoamine oxidase B (MAO-B) inhibitor used to treat Parkinson's disease. Selegiline has been found to have neuroprotective properties and may be useful for the expression of neurotrophins. The aim of this study was to evaluate the expression levels of neurotrophin genes in spinal cord rats treated with selegiline. METHODS Rats were divided into four groups: injury (control), laminectomy, sham (injured rat received 1 ml saline intraperitoneally) and treatment (injured rat received 5 mg/kg selegiline intraperitoneally for 7 days; once a day). The BBB scale (Basso, Beattie and Bresnahan) was performed once a week for 4 weeks to assess motor function after a spinal cord injury. On day 28 after SCI, the rat was sacrificed and the spinal cord lesion removed. A real-time PCR approach was used to assess neurotrophin gene expression. RESULTS The results showed that administration of selegiline improves locomotor function and increases mRNA levels of BDNF, GDNF, NT-3, and NT-4. CONCLUSION In summary, the results of this study suggest that selegiline may be an appropriate treatment for spinal cord injuries.
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Affiliation(s)
- Alireza Abdanipour
- Department of Anatomy, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Mojgan Mirzaei
- Department of Anatomy, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Iraj Jafari Anarkooli
- Department of Anatomy, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Parvin Mohammadi
- Department of Medical Biotechnology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
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12
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Xiang W, Cao H, Tao H, Jin L, Luo Y, Tao F, Jiang T. Applications of chitosan-based biomaterials: From preparation to spinal cord injury neuroprosthetic treatment. Int J Biol Macromol 2023; 230:123447. [PMID: 36708903 DOI: 10.1016/j.ijbiomac.2023.123447] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/04/2022] [Accepted: 01/24/2023] [Indexed: 01/27/2023]
Abstract
Spinal cord injury (SCI)-related disabilities are a serious problem in the modern society. Further, the treatment of SCI is highly challenging and is urgently required in clinical practice. Research on nerve tissue engineering is an emerging approach for improving the treatment outcomes of SCI. Chitosan (CS) is a cationic polysaccharide derived from natural biomaterials. Chitosan has been found to exhibit excellent biological properties, such as nontoxicity, biocompatibility, biodegradation, and antibacterial activity. Recently, chitosan-based biomaterials have attracted significant attention for SCI repair in nerve tissue engineering applications. These studies revealed that chitosan-based biomaterials have various functions and mechanisms to promote SCI repair, such as promoting neural cell growth, guiding nerve tissue regeneration, delivering nerve growth factors, and as a vector for gene therapy. Chitosan-based biomaterials have proven to have excellent potential for the treatment of SCI. This review aims to introduce the recent advances in chitosan-based biomaterials for SCI treatment and to highlight the prospects for further application.
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Affiliation(s)
- Wei Xiang
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430060, China
| | - Hui Cao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430060, China
| | - Hai Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430060, China
| | - Lin Jin
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430060, China
| | - Yue Luo
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430060, China
| | - Fenghua Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430060, China.
| | - Ting Jiang
- Department of Neurological Rehabilitation, Zhongnan Hospital of Wuhan University, Wuhan 430071, China.
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13
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Szymoniuk M, Litak J, Sakwa L, Dryla A, Zezuliński W, Czyżewski W, Kamieniak P, Blicharski T. Molecular Mechanisms and Clinical Application of Multipotent Stem Cells for Spinal Cord Injury. Cells 2022; 12:120. [PMID: 36611914 PMCID: PMC9818156 DOI: 10.3390/cells12010120] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/22/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Spinal Cord Injury (SCI) is a common neurological disorder with devastating psychical and psychosocial sequelae. The majority of patients after SCI suffer from permanent disability caused by motor dysfunction, impaired sensation, neuropathic pain, spasticity as well as urinary complications, and a small number of patients experience a complete recovery. Current standard treatment modalities of the SCI aim to prevent secondary injury and provide limited recovery of lost neurological functions. Stem Cell Therapy (SCT) represents an emerging treatment approach using the differentiation, paracrine, and self-renewal capabilities of stem cells to regenerate the injured spinal cord. To date, multipotent stem cells including mesenchymal stem cells (MSCs), neural stem cells (NSCs), and hematopoietic stem cells (HSCs) represent the most investigated types of stem cells for the treatment of SCI in preclinical and clinical studies. The microenvironment of SCI has a significant impact on the survival, proliferation, and differentiation of transplanted stem cells. Therefore, a deep understanding of the pathophysiology of SCI and molecular mechanisms through which stem cells act may help improve the treatment efficacy of SCT and find new therapeutic approaches such as stem-cell-derived exosomes, gene-modified stem cells, scaffolds, and nanomaterials. In this literature review, the pathogenesis of SCI and molecular mechanisms of action of multipotent stem cells including MSCs, NSCs, and HSCs are comprehensively described. Moreover, the clinical efficacy of multipotent stem cells in SCI treatment, an optimal protocol of stem cell administration, and recent therapeutic approaches based on or combined with SCT are also discussed.
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Affiliation(s)
- Michał Szymoniuk
- Student Scientific Association at the Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
| | - Jakub Litak
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
- Department of Clinical Immunology, Medical University of Lublin, Chodźki 4A, 20-093 Lublin, Poland
| | - Leon Sakwa
- Student Scientific Society, Kazimierz Pulaski University of Technologies and Humanities in Radom, Chrobrego 27, 26-600 Radom, Poland
| | - Aleksandra Dryla
- Student Scientific Association at the Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
| | - Wojciech Zezuliński
- Student Scientific Association at the Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
| | - Wojciech Czyżewski
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
- Department of Didactics and Medical Simulation, Medical University of Lublin, Chodźki 4, 20-093 Lublin, Poland
| | - Piotr Kamieniak
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
| | - Tomasz Blicharski
- Department of Rehabilitation and Orthopaedics, Medical University in Lublin, Jaczewskiego 8, 20-954 Lublin, Poland
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14
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Brown AD, Fogarty MJ, Davis LA, Dasgupta D, Mantilla CB, Sieck GC. Mitochondrial adaptations to inactivity in diaphragm muscle fibers. J Appl Physiol (1985) 2022; 133:191-204. [PMID: 35678745 PMCID: PMC9291409 DOI: 10.1152/japplphysiol.00090.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Type I and IIa diaphragm muscle (DIAm) fibers comprise slow and fast fatigue-resistant motor units that are recruited to accomplish breathing and thus have a high duty cycle. In contrast, type IIx/IIb fibers comprise more fatigable fast motor units that are infrequently recruited for airway protective and straining behaviors. We hypothesize that mitochondrial structure and function in type I and IIa DIAm fibers adapt in response to inactivity imposed by spinal cord hemisection at C2 (C2SH). At 14 days after C2SH, the effect of inactivity on mitochondrial structure and function was assessed in DIAm fibers. Mitochondria in DIAm fibers were labeled using MitoTracker Green (Thermo Fisher Scientific), imaged in three-dimensions (3-D) by fluorescence confocal microscopy, and images were analyzed for mitochondrial volume density (MVD) and complexity. DIAm homogenate from either side was assessed for PGC1α, Parkin, MFN2, and DRP1 using Western blot. In alternate serial sections of the same DIAm fibers, the maximum velocity of the succinate dehydrogenase reaction (SDHmax) was determined using a quantitative histochemical technique. In all groups and both sides of the DIAm, type I and IIa DIAm fibers exhibited higher MVD, with more filamentous mitochondria and had higher SDHmax normalized to both fiber volume and mitochondrial volume compared with type IIx/IIb Diam fibers. In the inactive right side of the DIAm, mitochondria became fragmented and MVD decreased in all fiber types compared with the intact side and sham controls, consistent with the observed reduction in PGC1α and increased Parkin and DRP1 expression. In the inactive side of the DIAm, the reduction in SDHmax was found only for type I and IIa fibers. These results show that there are intrinsic fiber-type-dependent differences in the structure and function of mitochondria in DIAm fibers. Following C2SH-induced inactivity, mitochondrial structure (MVD and fragmentation) and function (SDHmax) were altered, indicating that inactivity influences all DIAm fiber types, but inactivity disproportionately affected SDHmax in the more intrinsically active type I and IIa fibers.NEW & NOTEWORTHY Two weeks of diaphragm (DIAm) inactivity imposed by C2SH caused reduced mitochondrial volume density, mitochondrial fragmentation, and a concomitant reduction of SDHmax in type I and IIa DIAm fibers on the lesioned side. Type I and IIa DIAm fibers were far more sensitive to inactivation than type IIx/IIb fibers, which exhibited little pathology. Our results indicate that mitochondria in DIAm fibers are plastic in response to varying levels of activity.
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15
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Automated evaluation of respiratory signals to provide insight into respiratory drive. Respir Physiol Neurobiol 2022; 300:103872. [PMID: 35218924 DOI: 10.1016/j.resp.2022.103872] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 01/17/2023]
Abstract
The diaphragm muscle (DIAm) is the primary inspiratory muscle in mammals and is highly active throughout life displaying rhythmic activity. The repetitive activation of the DIAm (and of other muscles driven by central pattern generator activity) presents an opportunity to analyze these physiological data on a per-event basis rather than pooled on a per-subject basis. The present study highlights the development and implementation of a graphical user interface-based algorithm using an analysis of critical points to detect the onsets and offsets of individual respiratory events across a range of motor behaviors, thus facilitating analyses of within-subject variability. The algorithm is designed to be robust regardless of the signal type (e.g., EMG or transdiaphragmatic pressure). Our findings suggest that this approach may be particularly beneficial in reducing animal numbers in certain types of studies, for assessments of perturbation studies where the effects are relatively small but potentially physiologically meaningful, and for analyses of respiratory variability.
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16
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Zhao J, Pang A, Yin S, Yang M, Zhang X, Zhang R, Liu J, Gu Y, Li S, Hu Y, Zhang Y, Ba Y, Meng B, Yang X. Peptide OM-LV20 promotes structural and functional recovery of spinal cord injury in rats. Biochem Biophys Res Commun 2022; 598:124-130. [PMID: 35158211 DOI: 10.1016/j.bbrc.2022.02.017] [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: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 11/02/2022]
Abstract
At present, there are no satisfactory therapeutic drugs for the functional recovery of spinal cord injury (SCI). We previously identified a novel peptide (OM-LV20) that accelerated the regeneration of injured skin tissues of mice and exerts neuroprotective effects against cerebral ischemia/reperfusion injury in rats. Here, the intraperitoneal injection of OM-LV20 (1 μg/kg) markedly improved motor function recovery in the hind limbs of rats with traumatic SCI, and further enhanced spinal cord repair. Administration of OM-LV20 increased the number of surviving neuron bodies, as well as the expression levels of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB). In the acute stage of SCI, OM-LV20 treatment also increased superoxide dismutase and glutathione content but decreased the levels of malonaldehyde and nitric oxide. Thus, OM-LV20 significantly promoted structural and functional recovery of SCI in adult rats by increasing neuronal survival and BDNF and TrkB expression, and thereby regulating the balance of oxidative stress. Based on our knowledge, this research is the first report on the effects of amphibian-derived peptide on the recovery of SCI and our results highlight the potential of peptide OM-LV20 administration in the acceleration of the recovery of SCI.
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Affiliation(s)
- Jian Zhao
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Ailang Pang
- Department of Neurology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650031, China
| | - Saige Yin
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Meifeng Yang
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Xuemei Zhang
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Rong Zhang
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Jingfei Liu
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Yuanqi Gu
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Shanshan Li
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Yan Hu
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Yue Zhang
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Yingchun Ba
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China.
| | - Buliang Meng
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China.
| | - Xinwang Yang
- Department of Anatomy and Histology and Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, 650500, China.
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17
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Allen LL, Nichols NL, Asa ZA, Emery AT, Ciesla MC, Santiago JV, Holland AE, Mitchell GS, Gonzalez-Rothi EJ. Phrenic motor neuron survival below cervical spinal cord hemisection. Exp Neurol 2021; 346:113832. [PMID: 34363808 PMCID: PMC9065093 DOI: 10.1016/j.expneurol.2021.113832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 02/04/2023]
Abstract
Cervical spinal cord injury (cSCI) severs bulbospinal projections to respiratory motor neurons, paralyzing respiratory muscles below the injury. C2 spinal hemisection (C2Hx) is a model of cSCI often used to study spontaneous and induced plasticity and breathing recovery post-injury. One key assumption is that C2Hx dennervates motor neurons below the injury, but does not affect their survival. However, a recent study reported substantial bilateral motor neuron death caudal to C2Hx. Since phrenic motor neuron (PMN) death following C2Hx would have profound implications for therapeutic strategies designed to target spared neural circuits, we tested the hypothesis that C2Hx minimally impacts PMN survival. Using improved retrograde tracing methods, we observed no loss of PMNs at 2- or 8-weeks post-C2Hx. We also observed no injury-related differences in ChAT or NeuN immunolabeling within labelled PMNs. Although we found no evidence of PMN loss following C2Hx, we cannot rule out neuronal loss in other motor pools. These findings address an essential prerequisite for studies that utilize C2Hx as a model to explore strategies for inducing plasticity and/or regeneration within the phrenic motor system, as they provide important insights into the viability of phrenic motor neurons as therapeutic targets after high cervical injury.
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Affiliation(s)
- Latoya L Allen
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Zachary A Asa
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | | | - Marissa C Ciesla
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Juliet V Santiago
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Ashley E Holland
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Elisa J Gonzalez-Rothi
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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