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Dorrian RM, Leonard AV, Lauto A. Millimetric devices for nerve stimulation: a promising path towards miniaturization. Neural Regen Res 2024; 19:1702-1706. [PMID: 38103235 PMCID: PMC10960286 DOI: 10.4103/1673-5374.389627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/21/2023] [Accepted: 10/19/2023] [Indexed: 12/18/2023] Open
Abstract
Nerve stimulation is a rapidly developing field, demonstrating positive outcomes across several conditions. Despite potential benefits, current nerve stimulation devices are large, complicated, and are powered via implanted pulse generators. These factors necessitate invasive surgical implantation and limit potential applications. Reducing nerve stimulation devices to millimetric sizes would make these interventions less invasive and facilitate broader therapeutic applications. However, device miniaturization presents a serious engineering challenge. This review presents significant advancements from several groups that have overcome this challenge and developed millimetric-sized nerve stimulation devices. These are based on antennas, mini-coils, magneto-electric and opto-electronic materials, or receive ultrasound power. We highlight key design elements, findings from pilot studies, and present several considerations for future applications of these devices.
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Affiliation(s)
- Ryan M. Dorrian
- Spinal Cord Injury Research Group, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
| | - Anna V. Leonard
- Spinal Cord Injury Research Group, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
| | - Antonio Lauto
- School of Science, Western Sydney University, Penrith, NSW, Australia
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2
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Krieg JL, Leonard AV, Turner RJ, Corrigan F. Identifying the Phenotypes of Diffuse Axonal Injury Following Traumatic Brain Injury. Brain Sci 2023; 13:1607. [PMID: 38002566 PMCID: PMC10670443 DOI: 10.3390/brainsci13111607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023] Open
Abstract
Diffuse axonal injury (DAI) is a significant feature of traumatic brain injury (TBI) across all injury severities and is driven by the primary mechanical insult and secondary biochemical injury phases. Axons comprise an outer cell membrane, the axolemma which is anchored to the cytoskeletal network with spectrin tetramers and actin rings. Neurofilaments act as space-filling structural polymers that surround the central core of microtubules, which facilitate axonal transport. TBI has differential effects on these cytoskeletal components, with axons in the same white matter tract showing a range of different cytoskeletal and axolemma alterations with different patterns of temporal evolution. These require different antibodies for detection in post-mortem tissue. Here, a comprehensive discussion of the evolution of axonal injury within different cytoskeletal elements is provided, alongside the most appropriate methods of detection and their temporal profiles. Accumulation of amyloid precursor protein (APP) as a result of disruption of axonal transport due to microtubule failure remains the most sensitive marker of axonal injury, both acutely and chronically. However, a subset of injured axons demonstrate different pathology, which cannot be detected via APP immunoreactivity, including degradation of spectrin and alterations in neurofilaments. Furthermore, recent work has highlighted the node of Ranvier and the axon initial segment as particularly vulnerable sites to axonal injury, with loss of sodium channels persisting beyond the acute phase post-injury in axons without APP pathology. Given the heterogenous response of axons to TBI, further characterization is required in the chronic phase to understand how axonal injury evolves temporally, which may help inform pharmacological interventions.
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Affiliation(s)
- Justin L Krieg
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Anna V Leonard
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Renée J Turner
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Frances Corrigan
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
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Krieg JL, Leonard AV, Tuner RJ, Corrigan F. Characterization of Traumatic Brain Injury in a Gyrencephalic Ferret Model Using the Novel Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA). Neurotrauma Rep 2023; 4:761-780. [PMID: 38028274 PMCID: PMC10659026 DOI: 10.1089/neur.2023.0047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2023] Open
Abstract
Traumatic brain injury (TBI) results from mechanical force to the brain and leads to a series of biochemical responses that further damage neurons and supporting cells. Clinically, most TBIs result from an impact to the intact skull, making closed head TBI pre-clinical models highly relevant. However, most of these closed head TBI models use lissencephalic rodents, which may not transduce biomechanical load in the same manner as gyrencephalic humans. To address this translational gap, this study aimed to characterize acute axonal injury and microglial responses in ferrets-the smallest gyrencephalic mammal. Injury was induced in male ferrets (Mustela furo; 1.20-1.51 kg; 6-9 months old) with the novel Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA) model. Animals were randomly allocated to either sham (n = 4), a 22J (joules) impact (n = 4), or a 27J impact (n = 4). Axonal injury was examined histologically with amyloid precursor protein (APP), neurofilament M (RMO 14.9) (RMO-14), and phosphorylated tau (AT180) and the microglial response with ionized calcium-binding adaptor molecule 1 at 24 h post-injury in gray and white matter regions. Graded axonal injury was observed with modest increases in APP and RMO-14 immunoreactivity in the 22J TBI group, mostly within the corpus callosum and fornix and more extensive diffuse axonal injury encompassing gray matter structures like the thalamus and hypothalamus in the 27J group. Accompanying microglial activation was only observed in the 27J group, most prominently within the white matter tracts in response to the larger amounts of axonal injury. The 27J, but not the 22J, group showed an increase in AT180 within the base of the sulci post-injury. This could suggest that the strain may be highest in this region, demonstrating the different responses in gyrencephalic compared to lissencephalic brains. The CHIMERA model in ferrets mimic many of the histopathological features of human closed head TBI acutely and provides a promising model to investigate the pathophysiology of TBI.
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Affiliation(s)
- Justin L. Krieg
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
| | - Anna V. Leonard
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
| | - Renee J. Tuner
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
| | - Frances Corrigan
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
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4
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Dorrian RM, Berryman CF, Lauto A, Leonard AV. Electrical stimulation for the treatment of spinal cord injuries: A review of the cellular and molecular mechanisms that drive functional improvements. Front Cell Neurosci 2023; 17:1095259. [PMID: 36816852 PMCID: PMC9936196 DOI: 10.3389/fncel.2023.1095259] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that causes severe loss of motor, sensory and autonomic functions. Additionally, many individuals experience chronic neuropathic pain that is often refractory to interventions. While treatment options to improve outcomes for individuals with SCI remain limited, significant research efforts in the field of electrical stimulation have made promising advancements. Epidural electrical stimulation, peripheral nerve stimulation, and functional electrical stimulation have shown promising improvements for individuals with SCI, ranging from complete weight-bearing locomotion to the recovery of sexual function. Despite this, there is a paucity of mechanistic understanding, limiting our ability to optimize stimulation devices and parameters, or utilize combinatorial treatments to maximize efficacy. This review provides a background into SCI pathophysiology and electrical stimulation methods, before exploring cellular and molecular mechanisms suggested in the literature. We highlight several key mechanisms that contribute to functional improvements from electrical stimulation, identify gaps in current knowledge and highlight potential research avenues for future studies.
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Affiliation(s)
- Ryan M. Dorrian
- Spinal Cord Injury Research Group, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia,*Correspondence: Ryan M. Dorrian,
| | | | - Antonio Lauto
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Anna V. Leonard
- Spinal Cord Injury Research Group, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
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Sorby-Adams AJ, Marian OC, Bilecki IM, Elms LE, Camargo J, Hall K, Crowther RG, Leonard AV, Wadsworth GI, Spear JH, Turner RJ, Jones CF. Neurological scoring and gait kinematics to assess functional outcome in an ovine model of ischaemic stroke. Front Neurol 2023; 14:1071794. [PMID: 36891474 PMCID: PMC9986303 DOI: 10.3389/fneur.2023.1071794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 01/27/2023] [Indexed: 02/22/2023] Open
Abstract
Background Assessment of functional impairment following ischaemic stroke is essential to determine outcome and efficacy of intervention in both clinical patients and pre-clinical models. Although paradigms are well described for rodents, comparable methods for large animals, such as sheep, remain limited. This study aimed to develop methods to assess function in an ovine model of ischaemic stroke using composite neurological scoring and gait kinematics from motion capture. Methods Merino sheep (n = 26) were anaesthetised and subjected to 2 hours middle cerebral artery occlusion. Animals underwent functional assessment at baseline (8-, 5-, and 1-day pre-stroke), and 3 days post-stroke. Neurological scoring was carried out to determine changes in neurological status. Ten infrared cameras measured the trajectories of 42 retro-reflective markers for calculation of gait kinematics. Magnetic resonance imaging (MRI) was performed at 3 days post-stroke to determine infarct volume. Intraclass Correlation Coefficients (ICC's) were used to assess the repeatability of neurological scoring and gait kinematics across baseline trials. The average of all baselines was used to compare changes in neurological scoring and kinematics at 3 days post-stroke. A principal component analysis (PCA) was performed to determine the relationship between neurological score, gait kinematics, and infarct volume post-stroke. Results Neurological scoring was moderately repeatable across baseline trials (ICC > 0.50) and detected marked impairment post-stroke (p < 0.05). Baseline gait measures showed moderate to good repeatability for the majority of assessed variables (ICC > 0.50). Following stroke, kinematic measures indicative of stroke deficit were detected including an increase in stance and stride duration (p < 0.05). MRI demonstrated infarction involving the cortex and/or thalamus (median 2.7 cm3, IQR 1.4 to 11.9). PCA produced two components, although association between variables was inconclusive. Conclusion This study developed repeatable methods to assess function in sheep using composite scoring and gait kinematics, allowing for the evaluation of deficit 3 days post-stroke. Despite utility of each method independently, there was poor association observed between gait kinematics, composite scoring, and infarct volume on PCA. This suggests that each of these measures has discreet utility for the assessment of stroke deficit, and that multimodal approaches are necessary to comprehensively characterise functional impairment.
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Affiliation(s)
- Annabel J Sorby-Adams
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Oana C Marian
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Isabella M Bilecki
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Levi E Elms
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Jonathan Camargo
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Kelly Hall
- School of Public Health, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Robert G Crowther
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, SA, Australia
| | - Anna V Leonard
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - George I Wadsworth
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Joshua H Spear
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Renée J Turner
- School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Claire F Jones
- School of Mechanical Engineering, Faculty of Sciences, Engineering and Technology, The University of Adelaide, Adelaide, SA, Australia.,Adelaide Spinal Research Group, Centre for Orthopaedics and Trauma Research, The University of Adelaide, North Terrace, SA, Australia.,Department of Orthopaedics and Trauma, Royal Adelaide Hospital, Adelaide, SA, Australia
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6
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Gayen CD, Bessen MA, Dorrian RM, Quarrington RD, Mulaibrahimovic A, Doig RLO, Freeman BJC, Leonard AV, Jones CF. A survival model of thoracic contusion spinal cord injury in the domestic pig. J Neurotrauma 2022; 40:965-980. [PMID: 36200622 DOI: 10.1089/neu.2022.0281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spinal cord injury (SCI) frequently results in motor, sensory and autonomic dysfunction for which there is currently no cure. Recent preclinical and clinical research has led to promising advances in treatment; however, therapeutics indicating promise in rodents have not translated successfully in human trials, likely due, in part, to gross anatomical and physiological differences between the species. Therefore, large animal models of SCI may facilitate the study of secondary injury processes that are influenced by scale, and assist the translation of potential therapeutic interventions. The aim of this study was to characterize two severities of thoracic contusion SCI in female domestic pigs, measuring motor function and spinal cord lesion characteristics, over two weeks post-SCI. A custom instrumented weight drop injury device was used to release a 50 g impactor from 10 cm (n=3) or 20 cm (n=7) onto the exposed dura, to induce a contusion at the T10 thoracic spinal level. Hind limb motor function was assessed at 8 and 13 days post-SCI using a 10-point scale. Volume and extent of lesion-associated signal hyperintensity in T2-weighted magnetic resonance (MR) images was assessed at 3, 7 and 14 days post-injury. Animals were transcardially perfused at 14 days post-SCI and spinal cord tissue was harvested for histological analysis. Bowel function was retained in all animals and transient urinary retention occurred in two animals after catheter removal. All animals displayed hind limb motor deficits. Animals in the 10 cm group demonstrated some stepping and weight bearing and scored a median 2-3 points higher on the 10-point motor function scale at 8 and 13 days post-SCI, than the 20 cm group. Histological lesion volume was 20 % greater, and 30 % less white matter was spared, in the 20 cm group than in the 10 cm group. The MR signal hyperintensity in the 20 cm injury group had a median cranial-caudal extent approximately 1.5 times greater than the 10 cm injury group at all three time points, and median volumes 1.8, 2.5 and 4.5 times greater at day 3, 7 and 14 post-injury, respectively. Regional differences in axonal injury were observed between groups, with amyloid precursor protein immunoreactivity greatest in the 20 cm group in spinal cord sections adjacent the injury epicenter. This study demonstrated graded injuries in a domestic pig strain, with outcome measures comparable to miniature pig models of contusion SCI. The model provides a vehicle for the study of SCI and potential treatments, particularly where miniature pig strains are not available and/or where small animal models are not appropriate for the research question.
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Affiliation(s)
- Christine D Gayen
- Translational Neuropathology Laboratory, School of Biomedicine, The University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Spinal Research Group, Centre for Orthopaedics and Trauma Research, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Madeleine A Bessen
- Adelaide Spinal Research Group, Centre for Orthopaedics and Trauma Research, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Ryan M Dorrian
- Translational Neuropathology Laboratory, School of Biomedicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Ryan D Quarrington
- Adelaide Spinal Research Group, Centre for Orthopaedics and Trauma Research, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Adnan Mulaibrahimovic
- Adelaide Spinal Research Group, Centre for Orthopaedics and Trauma Research, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Ryan L O'Hare Doig
- Neil Sachse Centre for Spinal Cord Research, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Brian J C Freeman
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Royal Adelaide Hospital, Adelaide South Australia, Australia
| | - Anna V Leonard
- Translational Neuropathology Laboratory, School of Biomedicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Claire F Jones
- Adelaide Spinal Research Group, Centre for Orthopaedics and Trauma Research, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
- School of Mechanical Engineering, The University of Adelaide, Adelaide, South Australia, Australia
- Department of Orthopaedics and Trauma, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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Sorby-Adams AJ, Learoyd AE, Bath PM, Burrows F, Farr TD, Leonard AV, Schiessl I, Allan SM, Turner RJ, Trueman RC. Glyceryl trinitrate for the treatment of ischaemic stroke: Determining efficacy in rodent and ovine species for enhanced clinical translation. J Cereb Blood Flow Metab 2021; 41:3248-3259. [PMID: 34039053 PMCID: PMC8669202 DOI: 10.1177/0271678x211018901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Hypertension is a leading risk factor for death and dependency after ischaemic stroke. However, administering anti-hypertensive medications post-stroke remains contentious with concerns regarding deleterious effects on cerebral blood flow and infarct expansion. This study sought to determine the effect of glyceryl trinitrate (GTN) treatment in both lissencephalic and gyrencephalic pre-clinical stroke models. Merino sheep underwent middle cerebral artery occlusion (MCAO) followed by GTN or control patch administration (0.2 mg/h). Monitoring of numerous physiologically relevant measures over 24 h showed that GTN administration was associated with decreased intracranial pressure, infarct volume, cerebral oedema and midline shift compared to vehicle treatment (p < 0.05). No significant changes in blood pressure or cerebral perfusion pressure were observed. Using optical imaging spectroscopy and laser speckle imaging, the effect of varying doses of GTN (0.69-50 µg/h) on cerebral blood flow and tissue oxygenation was examined in mice. No consistent effect was found. Additional mice undergoing MCAO followed by GTN administration (doses varying from 0-60 µg/h) also showed no improvement in infarct volume or neurological score within 24 h post-stroke. GTN administration significantly improved numerous stroke-related physiological outcomes in sheep but was ineffective in mice. This suggests that, whilst GTN administration could potentially benefit patients, further research into mechanisms of action are required.
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Affiliation(s)
- Annabel J Sorby-Adams
- Adelaide Medical School and Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Annastazia E Learoyd
- School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
| | - Philip M Bath
- Stroke Trials Unit, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Fiona Burrows
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Tracy D Farr
- School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
| | - Anna V Leonard
- Adelaide Medical School and Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Ingo Schiessl
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Geoffrey Jefferson Brain Research Centre, The Manchester Academic Health Science Centre, Northern Care Alliance NHS Group, University of Manchester, Manchester, UK
| | - Stuart M Allan
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Geoffrey Jefferson Brain Research Centre, The Manchester Academic Health Science Centre, Northern Care Alliance NHS Group, University of Manchester, Manchester, UK
| | - Renée J Turner
- Adelaide Medical School and Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Rebecca C Trueman
- School of Life Sciences, University of Nottingham Medical School, Nottingham, UK
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8
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McDonald SJ, Sharkey JM, Sun M, Kaukas LM, Shultz SR, Turner RJ, Leonard AV, Brady RD, Corrigan F. Beyond the Brain: Peripheral Interactions after Traumatic Brain Injury. J Neurotrauma 2021; 37:770-781. [PMID: 32041478 DOI: 10.1089/neu.2019.6885] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability, and there are currently no pharmacological treatments known to improve patient outcomes. Unquestionably, contributing toward a lack of effective treatments is the highly complex and heterogenous nature of TBI. In this review, we highlight the recent surge of research that has demonstrated various central interactions with the periphery as a potential major contributor toward this heterogeneity and, in particular, the breadth of research from Australia. We describe the growing evidence of how extracranial factors, such as polytrauma and infection, can significantly alter TBI neuropathology. In addition, we highlight how dysregulation of the autonomic nervous system and the systemic inflammatory response induced by TBI can have profound pathophysiological effects on peripheral organs, such as the heart, lung, gastrointestinal tract, liver, kidney, spleen, and bone. Collectively, this review firmly establishes TBI as a systemic condition. Further, the central and peripheral interactions that can occur after TBI must be further explored and accounted for in the ongoing search for effective treatments.
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Affiliation(s)
- Stuart J McDonald
- Department Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria, Australia
| | - Jessica M Sharkey
- Discipline of Anatomy and Pathology, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Mujun Sun
- Department Neuroscience, Monash University, Melbourne, Victoria, Australia
| | - Lola M Kaukas
- School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Sandy R Shultz
- Department Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Renee J Turner
- Discipline of Anatomy and Pathology, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Anna V Leonard
- Discipline of Anatomy and Pathology, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Rhys D Brady
- Department Neuroscience, Monash University, Melbourne, Victoria, Australia
| | - Frances Corrigan
- School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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9
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Sorby-Adams AJ, Leonard AV, Elms LE, Marian OC, Hoving JW, Yassi N, Vink R, Thornton E, Turner RJ. Determining the Temporal Profile of Intracranial Pressure Changes Following Transient Stroke in an Ovine Model. Front Neurosci 2019; 13:587. [PMID: 31338013 PMCID: PMC6629870 DOI: 10.3389/fnins.2019.00587] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 05/23/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Cerebral edema and elevated intracranial pressure (ICP) are the leading cause of death in the first week following stroke. Despite this, current treatments are limited and fail to address the underlying mechanisms of swelling, highlighting the need for targeted treatments. When screening promising novel agents, it is essential to use clinically relevant large animal models to increase the likelihood of successful clinical translation. As such, we sought to develop a survival model of transient middle cerebral artery occlusion (tMCAO) in the sheep and subsequently characterize the temporal profile of cerebral edema and elevated ICP following stroke in this novel, clinically relevant model. METHODS Merino-sheep (27M;31F) were anesthetized and subject to 2 h tMCAO with reperfusion or sham surgery. Following surgery, animals were allowed to recover and returned to their home pens. At preselected times points ranging from 1 to 7 days post-stroke, animals were re-anesthetized, ICP measured for 4 h, followed by imaging with MRI to determine cerebral edema, midline shift and infarct volume (FLAIR, T2 and DWI). Animals were subsequently euthanized and their brain removed for immunohistochemical analysis. Serum and cerebrospinal fluid samples were also collected and analyzed for substance P (SP) using ELISA. RESULTS Intracranial pressure and MRI scans were normal in sham animals. Following stroke, ICP rose gradually over time and by 5 days was significantly (p < 0.0001) elevated above sham levels. Profound cerebral edema was observed as early as 2 days post-stroke and continued to evolve out to 6 days, resulting in significant midline shift which was most prominent at 5 days post-stroke (p < 0.01), in keeping with increasing ICP. Serum SP levels were significantly elevated (p < 0.01) by 7 days post-tMCAO. CONCLUSION We have successfully developed a survival model of ovine tMCAO and characterized the temporal profile of ICP. Peak ICP elevation, cerebral edema and midline shift occurred at days 5-6 following stroke, accompanied by an elevation in serum SP. Our findings suggest that novel therapeutic agents screened in this model targeting cerebral edema and elevated ICP would most likely be effective when administered prior to 5 days, or as early as possible following stroke onset.
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Affiliation(s)
- Annabel J. Sorby-Adams
- Adelaide Medical School, Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Anna V. Leonard
- Adelaide Medical School, Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Levi E. Elms
- Adelaide Medical School, Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Oana C. Marian
- Adelaide Medical School, Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Jan W. Hoving
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- Department of Radiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Nawaf Yassi
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia
| | - Robert Vink
- Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Emma Thornton
- Adelaide Medical School, Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Renée J. Turner
- Adelaide Medical School, Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
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10
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Sorby-Adams AJ, Leonard AV, Hoving JW, Yassi N, Vink R, Wells AJ, Turner RJ. NK1-r Antagonist Treatment Comparable to Decompressive Craniectomy in Reducing Intracranial Pressure Following Stroke. Front Neurosci 2019; 13:681. [PMID: 31333402 PMCID: PMC6624444 DOI: 10.3389/fnins.2019.00681] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/13/2019] [Indexed: 12/29/2022] Open
Abstract
Background and Purpose: The morbidity and early mortality associated with stroke is largely attributable to cerebral edema and elevated intracranial pressure (ICP). Existing pharmacotherapies do not target the underlying pathophysiology and are often ineffective in sustainably lowering ICP, whilst decompressive craniectomy (DC) surgery is life-saving yet with surgical/peri-operative risk and increased morbidity in the elderly. Accordingly, there is an urgent need for therapies that directly target the mechanisms of edema genesis. Neurogenic inflammation, mediated by substance P (SP) binding to the tachykinin NK1 receptor (NK1-r), is associated with blood-brain barrier (BBB) disruption, cerebral edema and poor outcome post-stroke. NK1-r antagonist treatment ameliorates BBB dysfunction and cerebral edema in rodent stroke models. However, treatment has not been investigated in a large animal model, an important step toward clinical translation. Consequently, the current study compared the efficacy of NK1-r antagonist treatment to DC surgery in reducing ICP post-stroke in a clinically relevant ovine model. Methods: Anesthetized female Merino sheep (65 ± 6 kg, 18–24 months) underwent sham surgery (n = 4) or permanent middle cerebral artery occlusion (n = 22). Stroke animals were randomized into one of 5 treatments: 1×NK1 bolus (4 h), 2×NK1 bolus (4 h;9 h), 3×NK1 bolus (4 h;9 h;14 h), DC surgery (performed at 4 h) or saline vehicle. ICP, blood pressure and blood gasses were monitored for 24 h post-stroke. At 24 h post-stroke anesthetized animals underwent MRI followed by perfusion and brains removed and processed for histological assessment. Results: 2×NK1, 3×NK1 administration or DC surgery significantly (p < 0.05) reduced ICP compared to vehicle. 1×NK1 was ineffective in sustainably lowering ICP. On MRI, midline shift and cerebral edema were more marked in vehicles compared to NK1-r treatment groups. Conclusion: Two or three boluses of NK1-r antagonist treatment reduced ICP comparable to DC surgery, suggesting it may provide a novel alternative to invasive surgery for the management of elevated ICP.
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Affiliation(s)
- Annabel J Sorby-Adams
- Adelaide Medical School and Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Anna V Leonard
- Adelaide Medical School and Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - Jan W Hoving
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.,Department of Radiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Nawaf Yassi
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Robert Vink
- Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Adam J Wells
- Department of Neurosurgery, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Renée J Turner
- Adelaide Medical School and Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
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Corrigan F, Mander KA, Leonard AV, Vink R. Neurogenic inflammation after traumatic brain injury and its potentiation of classical inflammation. J Neuroinflammation 2016; 13:264. [PMID: 27724914 PMCID: PMC5057243 DOI: 10.1186/s12974-016-0738-9] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/28/2016] [Indexed: 01/05/2023] Open
Abstract
Background The neuroinflammatory response following traumatic brain injury (TBI) is known to be a key secondary injury factor that can drive ongoing neuronal injury. Despite this, treatments that have targeted aspects of the inflammatory pathway have not shown significant efficacy in clinical trials. Main body We suggest that this may be because classical inflammation only represents part of the story, with activation of neurogenic inflammation potentially one of the key initiating inflammatory events following TBI. Indeed, evidence suggests that the transient receptor potential cation channels (TRP channels), TRPV1 and TRPA1, are polymodal receptors that are activated by a variety of stimuli associated with TBI, including mechanical shear stress, leading to the release of neuropeptides such as substance P (SP). SP augments many aspects of the classical inflammatory response via activation of microglia and astrocytes, degranulation of mast cells, and promoting leukocyte migration. Furthermore, SP may initiate the earliest changes seen in blood-brain barrier (BBB) permeability, namely the increased transcellular transport of plasma proteins via activation of caveolae. This is in line with reports that alterations in transcellular transport are seen first following TBI, prior to decreases in expression of tight-junction proteins such as claudin-5 and occludin. Indeed, the receptor for SP, the tachykinin NK1 receptor, is found in caveolae and its activation following TBI may allow influx of albumin and other plasma proteins which directly augment the inflammatory response by activating astrocytes and microglia. Conclusions As such, the neurogenic inflammatory response can exacerbate classical inflammation via a positive feedback loop, with classical inflammatory mediators such as bradykinin and prostaglandins then further stimulating TRP receptors. Accordingly, complete inhibition of neuroinflammation following TBI may require the inhibition of both classical and neurogenic inflammatory pathways.
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Affiliation(s)
- Frances Corrigan
- Adelaide Centre for Neuroscience Research, School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia.
| | - Kimberley A Mander
- Adelaide Centre for Neuroscience Research, School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Anna V Leonard
- Adelaide Centre for Neuroscience Research, School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Robert Vink
- Sansom Institute for Health Research, The University of South Australia, Adelaide, South Australia, Australia
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Leonard AV, Thornton E, Vink R. The relative contribution of edema and hemorrhage to raised intrathecal pressure after traumatic spinal cord injury. J Neurotrauma 2015; 32:397-402. [PMID: 25111333 DOI: 10.1089/neu.2014.3543] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Raised intrathecal pressure (ITP) after traumatic spinal cord injury (SCI) is a critically important aspect of injury development that may result in significantly greater tissue damage and worsened functional outcome. Raised ITP is caused by the accumulation of blood and/or water (edema), and while their occurrence after traumatic SCI has been well established, the relative contribution of both processes to the development of ITP after SCI has not yet been determined. Accordingly, the current study investigates the temporal profile of raised ITP after traumatic SCI in relation to both hemorrhage and edema development. A closed balloon compression injury was induced at T10 in New Zealand White rabbits. Animals were thereafter assessed for spinal water content (edema), ITP, lesion and hemorrhage volume, and albumin immunoreactivity from 5 h to 1 week post-SCI. Early increases in ITP at 5 h post-injury were associated with significant increases in blood volume. ITP, however, was maximal at 3 days post-SCI, at which time there was an associated significant increase in edema that persisted for 1 week. We conclude that raised ITP after traumatic SCI is initially driven by volumetric increases in hemorrhage, while edema becomes the primary driver of ITP at 3 days post-injury.
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Affiliation(s)
- Anna V Leonard
- 1 Adelaide Centre for Neuroscience Research, School of Medical Sciences The University of Adelaide , South Australia, Australia
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13
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Leonard AV, Vink R. Reducing intrathecal pressure after traumatic spinal cord injury: a potential clinical target to promote tissue survival. Neural Regen Res 2015; 10:380-2. [PMID: 25878583 PMCID: PMC4396097 DOI: 10.4103/1673-5374.153683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2015] [Indexed: 11/15/2022] Open
Affiliation(s)
- Anna V Leonard
- School of Medical Sciences, University of Adelaide, Adelaide, Australia
| | - Robert Vink
- Division of Health Sciences, University of South Australia, Adelaide, Australia
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Leonard AV, Manavis J, Blumbergs PC, Vink R. Changes in substance P and NK1 receptor immunohistochemistry following human spinal cord injury. Spinal Cord 2013; 52:17-23. [PMID: 24216617 DOI: 10.1038/sc.2013.136] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 01/13/2023]
Abstract
STUDY DESIGN An immunohistological assessment of substance P (SP), its NK1 receptor and claudin-5 in human spinal cord injury (SCI) tissue. OBJECTIVE To determine whether SP and NK1 receptor immunoreactivity are altered following human traumatic SCI. SETTING Australia. SUMMARY OF BACKGROUND DATA SP has been implicated in the development of neurogenic inflammation and subsequent edema development following both traumatic brain injury and ischemic stroke. In these conditions, inhibition of its NK1 receptor has been shown to be neuroprotective as reflected in a reduction of edema and improved functional outcome. However, the role of SP following human SCI has not yet been assessed. METHODS Archived human SCI tissue was grouped according to survival times: control (no injury; n=5); immediate (death within an hour of the incident; n=6); 2-5 h (n=3); 3 days (n=5); 1 week (n=3); and 3-4 weeks (n=6). Sections were assessed for SP, its NK1 receptor and claudin-5 using immunohistochemical techniques. RESULTS Following SCI, dorsal horn SP immunoreactivity demonstrated a profound decrease compared with control tissue, indicating the loss of SP with SCI. A marked increase in perivascular NK1 staining was demonstrated after SCI compared with control levels. No obvious change in claudin-5 immunoreactivity was present immediately following injury, however, by 1 week post-SCI, decreased levels were noted. CONCLUSION This study demonstrates that severe acute traumatic human SCI results in decreased SP and an immediate increase in NK1 receptor immunoreactivity, suggesting that there is a neurogenic inflammatory component following human SCI.
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Affiliation(s)
- A V Leonard
- School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - J Manavis
- Hanson Institute Centre for Neurological Diseases/SA Pathology, Adelaide, South Australia, Australia
| | - P C Blumbergs
- 1] School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia [2] Hanson Institute Centre for Neurological Diseases/SA Pathology, Adelaide, South Australia, Australia
| | - R Vink
- School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
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Leonard AV, Thornton E, Vink R. Substance P as a mediator of neurogenic inflammation after balloon compression induced spinal cord injury. J Neurotrauma 2013; 30:1812-23. [PMID: 23924052 DOI: 10.1089/neu.2013.2993] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Although clinical spinal cord injury (SCI) occurs within a closed environment, most experimental models of SCI create an open injury. Such an open environment precludes the measurement of intrathecal pressure (ITP), whose increase after SCI has been linked to the development of greater tissue damage and functional deficits. Raised ITP may be potentiated by edema, which we have recently shown to be associated with substance P (SP) induced neurogenic inflammation in both traumatic brain injury and stroke. The present study investigates whether SP plays a similar role as a mediator of neurogenic inflammation after SCI. A closed balloon compression injury was induced at T10 in New Zealand white rabbits. Animals were thereafter assessed for blood spinal cord barrier (BSCB) permeability, edema, ITP, histological outcome, and functional outcome from 5 h to 2 weeks post-SCI. The balloon compression model produced significant increases in BSCB permeability, edema, and ITP along with significant functional deficits that persisted for 2 weeks. Histological assessment demonstrated decreased SP immunoreactivity in the injured spinal cord while NK1 receptor immunoreactivity initially increased before returning to sham levels. In addition, aquaporin 4 immunoreactivity increased early post-SCI, implicating this water channel in the development of edema after SCI. The changes described in the present study support a role for SP as a mediator of neurogenic inflammation after SCI.
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Affiliation(s)
- Anna V Leonard
- The School of Medical Sciences, Level 4, Medical School South, The University of Adelaide , Adelaide, South Australia, Australia
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Corrigan F, Thornton E, Roisman LC, Leonard AV, Vink R, Blumbergs PC, van den Heuvel C, Cappai R. The neuroprotective activity of the amyloid precursor protein against traumatic brain injury is mediated via the heparin binding site in residues 96-110. J Neurochem 2013; 128:196-204. [DOI: 10.1111/jnc.12391] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 12/11/2022]
Affiliation(s)
- Frances Corrigan
- Discipline of Anatomy and Pathology; School of Medical Sciences; University of Adelaide; Adelaide SA Australia
| | - Emma Thornton
- Discipline of Anatomy and Pathology; School of Medical Sciences; University of Adelaide; Adelaide SA Australia
| | - Laila C. Roisman
- Department of Pathology and Bio21 Molecular Science and BioTechnology Institute; The University of Melbourne; Victoria Australia
| | - Anna V. Leonard
- Discipline of Anatomy and Pathology; School of Medical Sciences; University of Adelaide; Adelaide SA Australia
| | - Robert Vink
- Discipline of Anatomy and Pathology; School of Medical Sciences; University of Adelaide; Adelaide SA Australia
| | - Peter C. Blumbergs
- Centre for Neurological Diseases; Hanson Institute; Adelaide SA Australia
| | - Corinna van den Heuvel
- Discipline of Anatomy and Pathology; School of Medical Sciences; University of Adelaide; Adelaide SA Australia
| | - Roberto Cappai
- Department of Pathology and Bio21 Molecular Science and BioTechnology Institute; The University of Melbourne; Victoria Australia
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Gabrielian L, Helps SC, Thornton E, Turner RJ, Leonard AV, Vink R. Substance P antagonists as a novel intervention for brain edema and raised intracranial pressure. Acta Neurochir Suppl 2013; 118:201-4. [PMID: 23564132 DOI: 10.1007/978-3-7091-1434-6_37] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Increased intracranial pressure (ICP) following acute brain injury requires the accumulation of additional water in the intracranial vault. One source of such water is the vasculature, although the mechanisms associated with control of blood-brain barrier permeability are unclear. We have recently shown that acute brain injury, such as neurotrauma and stroke, results in perivascular accumulation of the neuropeptide, substance P. This accumulation is associated with increased blood-brain barrier permeability and formation of vasogenic edema. Administration of a substance P antagonist targeting the tachykinin NK1 receptor profoundly reduced the increased blood-brain barrier permeability and edema formation, and in small animal models of acute brain injury, improved functional outcome. In a large, ovine model of experimental traumatic brain injury, trauma resulted in a significant increase in ICP. Administration of an NK1 antagonist caused a profound reduction in post--traumatic ICP, with levels returning to normal within 4 h of drug administration. Substance P NK1 antagonists offer a novel therapeutic approach to the treatment of acute brain injury.
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Affiliation(s)
- Levon Gabrielian
- School of Medical Sciences, University of Adelaide, Adelaide, SA, Australia
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