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Xiong G, Jean I, Farrugia AM, Metheny H, Johnson BN, Cohen NA, Cohen AS. Temporal and structural sensitivities of major biomarkers for detecting neuropathology after traumatic brain injury in the mouse. Front Neurosci 2024; 18:1339262. [PMID: 38356651 PMCID: PMC10865493 DOI: 10.3389/fnins.2024.1339262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/08/2024] [Indexed: 02/16/2024] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of morbidity and mortality, especially in teenagers to young adults. In recent decades, different biomarkers and/or staining protocols have been employed to evaluate the post-injury development of pathological structures, but they have produced many contradictory findings. Since correctly identifying the underlying neuroanatomical changes is critical to advancing TBI research, we compared three commonly used markers for their ability to detect TBI pathological structures: Fluoro-Jade C, the rabbit monoclonal antibody Y188 against amyloid precursor protein and the NeuroSilver kit were used to stain adjacent slices from naïve or injured mouse brains harvested at different time points from 30 min to 3 months after lateral fluid percussion injury. Although not all pathological structures were stained by all markers at all time points, we found damaged neurons and deformed dendrites in gray matter, punctate and perivascular structures in white matter, and axonal blebs and Wallerian degeneration in both gray and white matter. The present study demonstrates the temporal and structural sensitivities of the three biomarkers: each marker is highly effective for a set of pathological structures, each of which in turn emerges at a particular time point. Furthermore, the different biomarkers showed different abilities at detecting identical types of pathological structures. In contrast to previous studies that have used a single biomarker at a single time range, the present report strongly recommends that a combination of different biomarkers should be adopted and different time points need to be checked when assessing neuropathology after TBI.
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Affiliation(s)
- Guoxiang Xiong
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Ian Jean
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Anthony M. Farrugia
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Hannah Metheny
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Brian N. Johnson
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Noam A. Cohen
- Philadelphia Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Otorhinolaryngology−Head and Neck Surgery, Philadelphia, PA, United States
| | - Akiva S. Cohen
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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2
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Janković T, Pilipović K. Single Versus Repetitive Traumatic Brain Injury: Current Knowledge on the Chronic Outcomes, Neuropathology and the Role of TDP-43 Proteinopathy. Exp Neurobiol 2023; 32:195-215. [PMID: 37749924 PMCID: PMC10569144 DOI: 10.5607/en23008] [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: 02/16/2023] [Revised: 07/18/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023] Open
Abstract
Traumatic brain injury (TBI) is one of the most important causes of death and disability in adults and thus an important public health problem. Following TBI, secondary pathophysiological processes develop over time and condition the development of different neurodegenerative entities. Previous studies suggest that neurobehavioral changes occurring after a single TBI are the basis for the development of Alzheimer's disease, while repetitive TBI is considered to be a contributing factor for chronic traumatic encephalopathy development. However, pathophysiological processes that determine the evolvement of a particular chronic entity are still unclear. Human post-mortem studies have found combinations of amyloid, tau, Lewi bodies, and TAR DNA-binding protein 43 (TDP-43) pathologies after both single and repetitive TBI. This review focuses on the pathological changes of TDP-43 after single and repetitive brain traumas. Numerous studies have shown that TDP-43 proteinopathy noticeably occurs after repetitive head trauma. A relatively small number of available preclinical research on single brain injury are not in complete agreement with the results from the human samples, which makes it difficult to draw specific conclusions. Also, as TBI is considered a heterogeneous type of injury, different experimental trauma models and injury intensities may cause differences in the cascade of secondary injury, which should be considered in future studies. Experimental and post-mortem studies of TDP-43 pathobiology should be carried out, preferably in the same laboratories, to determine its involvement in the development of neurodegenerative conditions after one and repetitive TBI, especially in the context of the development of new therapeutic options.
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Affiliation(s)
- Tamara Janković
- Department of Basic and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia
| | - Kristina Pilipović
- Department of Basic and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia
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3
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Michaud J, Plu I, Parai J, Bourgault A, Tanguay C, Seilhean D, Woulfe J. Ballooned neurons in semi-recent severe traumatic brain injury. Acta Neuropathol Commun 2023; 11:37. [PMID: 36899399 PMCID: PMC9999665 DOI: 10.1186/s40478-023-01516-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/12/2023] [Indexed: 03/12/2023] Open
Abstract
Traumatic brain injury (TBI) is now recognized as an insult triggering a dynamic process of degeneration and regeneration potentially evolving for years with chronic traumatic encephalopathy (CTE) as one major complication. Neurons are at the center of the clinical manifestations, both in the acute and chronic phases. Yet, in the acute phase, conventional neuropathology detects abnormalities predominantly in the axons, if one excludes contusions and hypoxic ischemic changes. We report the finding of ballooned neurons, predominantly in the anterior cingulum, in three patients who sustained severe TBI and remained comatose until death, 2 ½ weeks to 2 ½ months after the traumatic impact. All three cases showed severe changes of traumatic diffuse axonal injury in line with acceleration/deceleration forces. The immunohistochemical profile of the ballooned neurons was like that described in neurodegenerative disorders like tauopathies which were used as controls. The presence of αB-crystallin positive ballooned neurons in the brain of patients who sustained severe craniocerebral trauma and remained comatose thereafter has never been reported. We postulate that the co-occurrence of diffuse axonal injury in the cerebral white matter and ballooned neurons in the cortex is mechanistically reminiscent of the phenomenon of chromatolysis. Experimental trauma models with neuronal chromatolytic features emphasized the presence of proximal axonal defects. In our three cases, proximal swellings were documented in the cortex and subcortical white matter. This limited retrospective report should trigger further studies in order to better establish, in recent/semi-recent TBI, the frequency of this neuronal finding and its relationship with the proximal axonal defects.
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Affiliation(s)
- Jean Michaud
- Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Canada.
| | - Isabelle Plu
- Raymond Escourolle Département de Neuropathologie, Hôpital Pitié-Salpêtrière, APHP, Université de La Sorbonne, Paris, France.,Institut Médico-Légal, Paris, France
| | - Jacqueline Parai
- Eastern Ontario Forensic Pathology Unit, University of Ottawa, Ottawa, Canada
| | - André Bourgault
- Laboratoire de Sciences Judiciaires Et de Médecine Légale, Montréal, Québec, Canada
| | - Caroline Tanguay
- Laboratoire de Sciences Judiciaires Et de Médecine Légale, Montréal, Québec, Canada
| | - Danielle Seilhean
- Raymond Escourolle Département de Neuropathologie, Hôpital Pitié-Salpêtrière, APHP, Université de La Sorbonne, Paris, France
| | - John Woulfe
- Department of Pathology and Laboratory Medicine, The Ottawa Hospital, University of Ottawa, Ottawa, Canada.,Program in Neuroscience, Ottawa Hospital Research Institute, Ottawa, Canada
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4
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Chen Q, Chen X, Xu L, Zhang R, Li Z, Yue X, Qiao D. Traumatic axonal injury: neuropathological features, postmortem diagnostic methods, and strategies. Forensic Sci Med Pathol 2022; 18:530-544. [PMID: 36117238 DOI: 10.1007/s12024-022-00522-0] [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] [Accepted: 08/24/2022] [Indexed: 12/14/2022]
Abstract
Traumatic brain injury (TBI) has high morbidity and poor prognosis and imposes a serious socioeconomic burden. Traumatic axonal injury (TAI), which is one of the common pathological changes in the primary injury of TBI, is often caused by the external force to the head that causes the white matter bundles to generate shear stress and tension; resulting in tissue damage and leading to the cytoskeletal disorder. At present, the forensic pathological diagnosis of TAI-caused death is still a difficult problem. Most of the TAI biomarkers studied are used for the prediction, evaluation, and prognosis of TAI in the living state. The research subjects are mainly humans in the living state or model animals, which are not suitable for the postmortem diagnosis of TAI. In addition, there is still a lack of recognized indicators for the autopsy pathological diagnosis of TAI. Different diagnostic methods and markers have their limitations, and there is a lack of systematic research and summary of autopsy diagnostic markers of TAI. Therefore, this study mainly summarizes the pathological mechanism, common methods, techniques of postmortem diagnosis, and corresponding biomarkers of TAI, and puts forward the strategies for postmortem diagnosis of TAI for forensic cases with different survival times, which is of great significance to forensic pathological diagnosis.
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Affiliation(s)
- Qianling Chen
- School of Forensic Medicine, Southern Medical University, South Shaitai Road #1023, Guangzhou, 510515, Guangdong, China
| | - Xuebing Chen
- School of Forensic Medicine, Southern Medical University, South Shaitai Road #1023, Guangzhou, 510515, Guangdong, China
| | - Luyao Xu
- School of Forensic Medicine, Southern Medical University, South Shaitai Road #1023, Guangzhou, 510515, Guangdong, China
| | - Rui Zhang
- School of Forensic Medicine, Southern Medical University, South Shaitai Road #1023, Guangzhou, 510515, Guangdong, China
| | - Zhigang Li
- Guangzhou Forensic Science Institute & Key Laboratory of Forensic Pathology, Ministry of Public Security, Guangzhou, 510442, China.
| | - Xia Yue
- School of Forensic Medicine, Southern Medical University, South Shaitai Road #1023, Guangzhou, 510515, Guangdong, China.
| | - Dongfang Qiao
- School of Forensic Medicine, Southern Medical University, South Shaitai Road #1023, Guangzhou, 510515, Guangdong, China.
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5
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Refined Analysis of Chronic White Matter Changes after Traumatic Brain Injury and Repeated Sports-Related Concussions: Of Use in Targeted Rehabilitative Approaches? J Clin Med 2022; 11:jcm11020358. [PMID: 35054052 PMCID: PMC8780504 DOI: 10.3390/jcm11020358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/03/2022] [Accepted: 01/08/2022] [Indexed: 12/10/2022] Open
Abstract
Traumatic brain injury (TBI) or repeated sport-related concussions (rSRC) may lead to long-term memory impairment. Diffusion tensor imaging (DTI) is helpful to reveal global white matter damage but may underestimate focal abnormalities. We investigated the distribution of post-injury regional white matter changes after TBI and rSRC. Six patients with moderate/severe TBI, and 12 athletes with rSRC were included ≥6 months post-injury, and 10 (age-matched) healthy controls (HC) were analyzed. The Repeatable Battery for the Assessment of Neuropsychological Status was performed at the time of DTI. Major white matter pathways were tracked using q-space diffeomorphic reconstruction and analyzed for global and regional changes with a controlled false discovery rate. TBI patients displayed multiple classic white matter injuries compared with HC (p < 0.01). At the regional white matter analysis, the left frontal aslant tract, anterior thalamic radiation, and the genu of the corpus callosum displayed focal changes in both groups compared with HC but with different trends. Both TBI and rSRC displayed worse memory performance compared with HC (p < 0.05). While global analysis of DTI-based parameters did not reveal common abnormalities in TBI and rSRC, abnormalities to the fronto-thalamic network were observed in both groups using regional analysis of the white matter pathways. These results may be valuable to tailor individualized rehabilitative approaches for post-injury cognitive impairment in both TBI and rSRC patients.
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6
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Hernandez ML, Marone M, Gorse KM, Lafrenaye AD. Cathepsin B Relocalization in Late Membrane Disrupted Neurons Following Diffuse Brain Injury in Rats. ASN Neuro 2022; 14:17590914221099112. [PMID: 35503242 PMCID: PMC9069603 DOI: 10.1177/17590914221099112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/13/2022] [Accepted: 04/20/2022] [Indexed: 12/23/2022] Open
Abstract
Traumatic brain injury (TBI) has consequences that last for years following injury. While TBI can precipitate a variety of diffuse pathologies, the mechanisms involved in injury-induced neuronal membrane disruption remain elusive. The lysosomal cysteine protease, Cathepsin B (Cath B), and specifically its redistribution into the cytosol has been implicated in cell death. Little is known about Cath B or neuronal membrane disruption chronically following diffuse TBI. Therefore, the current study evaluated Cath B and diffuse neuronal membrane disruption over a more chronic post-injury window (6 h-4 w). We evaluated Cath B in adult male Sprague-Dawley rats following central fluid percussion injury (CFPI). Expression of Cath B, as well as Cath B-associated pro (Bak and AIF) and anti-apoptotic (Bcl-xl) proteins, were assessed using western blot analysis. Cath B activity was also assessed. Localization of Cath B was evaluated in the membrane disrupted and non-disrupted population following CFPI using immunohistochemistry paired with quantitative image analysis and ultrastructural verification. There was no difference in expression or activity of Cath B or any of the associated proteins between sham and CFPI at any time post-injury. Immunohistological studies, however, showed a sub-cellular re-localization of Cath B at 2 w and 4 w post-injury in the membrane disrupted neuronal population as compared to the time-point matched non-disrupted neurons. Both membrane disruption and Cath B relocalization appear linked to neuronal atrophy. These observations are indicative of a late secondary pathology that represents an opportunity for therapeutic treatment of these neurons following diffuse TBI. Summary Statement Lysosomal cathepsin B relocalizes to the cytosol in neurons with disrupted plasmalemmal membranes weeks following diffuse brain injury. Both the membrane disrupted and cathepsin B relocalized neuronal subpopulations displayed smaller soma and nucleus size compared to non-pathological neurons, indicating atrophy.
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Affiliation(s)
- Martina L. Hernandez
- Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Michael Marone
- Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Karen M. Gorse
- Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Audrey D. Lafrenaye
- Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
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Dhote VV, Raja MKMM, Samundre P, Sharma S, Anwikar S, Upaganlawar AB. Sports Related Brain Injury and Neurodegeneration in Athletes. Curr Mol Pharmacol 2021; 15:51-76. [PMID: 34515018 DOI: 10.2174/1874467214666210910114324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/03/2021] [Accepted: 06/03/2021] [Indexed: 11/22/2022]
Abstract
Sports deserve a special place in human life to impart healthy and refreshing wellbeing. However, sports activities, especially contact sports, renders athlete vulnerable to brain injuries. Athletes participating in a contact sport like boxing, rugby, American football, wrestling, and basketball are exposed to traumatic brain injuries (TBI) or concussions. The acute and chronic nature of these heterogeneous injuries provides a spectrum of dysfunctions that alters the neuronal, musculoskeletal, and behavioral responses of an athlete. Many sports-related brain injuries go unreported, but these head impacts trigger neurometabolic disruptions that contribute to long-term neuronal impairment. The pathophysiology of post-concussion and its underlying mechanisms are undergoing intense research. It also shed light on chronic disorders like Parkinson's disease, Alzheimer's disease, and dementia. In this review, we examined post-concussion neurobehavioral changes, tools for early detection of signs, and their impact on the athlete. Further, we discussed the role of nutritional supplements in ameliorating neuropsychiatric diseases in athletes.
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Affiliation(s)
- Vipin V Dhote
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP,462044. India
| | | | - Prem Samundre
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP,462044. India
| | - Supriya Sharma
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP,462044. India
| | - Shraddha Anwikar
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP,462044. India
| | - Aman B Upaganlawar
- Faculty of Pharmacy, VNS Group of Institutions, Bhopal, MP,462044. India
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8
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Sargolzaei S, Kaushik A, Soltani S, Amini MH, Khalghani MR, Khoshavi N, Sargolzaei A. Preclinical Western Blot in the Era of Digital Transformation and Reproducible Research, an Eastern Perspective. Interdiscip Sci 2021; 13:490-499. [PMID: 34080131 DOI: 10.1007/s12539-021-00442-7] [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: 07/07/2020] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 11/25/2022]
Abstract
The current research is an interdisciplinary endeavor to develop a necessary tool in preclinical protein studies of diseases or disorders through western blotting. In the era of digital transformation and open access principles, an interactive cloud-based database called East-West Blot ( https://rancs-lab.shinyapps.io/WesternBlots ) is designed and developed. The online interactive subject-specific database built on the R shiny platform facilitates a systematic literature search on the specific subject matter, here set to western blot studies of protein regulation in the preclinical model of TBI. The tool summarizes the existing publicly available knowledge through a data visualization technique and easy access to the critical data elements and links to the study itself. The application compiled a relational database of PubMed-indexed western blot studies labeled under HHS public access, reporting downstream protein regulations presented by fluid percussion injury model of traumatic brain injury. The promises of the developed tool include progressing toward implementing the principles of 3Rs (replacement, reduction, and refinement) for humane experiments, cultivating the prerequisites of reproducible research in terms of reporting characteristics, paving the ways for a more collaborative experimental design in basic science, and rendering an up-to-date and summarized perspective of current publicly available knowledge.
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Affiliation(s)
- Saman Sargolzaei
- Department of Engineering, University of Tennessee at Martin, Martin, TN, USA.
| | - Ajeet Kaushik
- Department of Natural Sciences, Florida Polytechnic University, Lakeland, FL, USA
| | - Seyed Soltani
- Mechanical Engineering Department, Florida Polytechnic University, Lakeland, FL, USA
| | - M Hadi Amini
- School of Computing and Information Sciences, Florida International University, Miami, FL, USA
| | - Mohammad Reza Khalghani
- Electrical and Computer Engineering Department, Florida Polytechnic University, Lakeland, FL, USA
| | - Navid Khoshavi
- Computer Science Department, Florida Polytechnic University, Lakeland, FL, USA
| | - Arman Sargolzaei
- Department of Mechanical Engineering, Tennessee Technological University, Cookeville, TN, USA
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9
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Pernici CD, Rowe RK, Doughty PT, Madadi M, Lifshitz J, Murray TA. Longitudinal optical imaging technique to visualize progressive axonal damage after brain injury in mice reveals responses to different minocycline treatments. Sci Rep 2020; 10:7815. [PMID: 32385407 PMCID: PMC7210987 DOI: 10.1038/s41598-020-64783-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/17/2020] [Indexed: 12/14/2022] Open
Abstract
A high-resolution, three-dimensional, optical imaging technique for the murine brain was developed to identify the effects of different therapeutic windows for preclinical brain research. This technique tracks the same cells over several weeks. We conducted a pilot study of a promising drug to treat diffuse axonal injury (DAI) caused by traumatic brain injury, using two different therapeutic windows, as a means to demonstrate the utility of this novel longitudinal imaging technique. DAI causes immediate, sporadic axon damage followed by progressive secondary axon damage. We administered minocycline for three days commencing one hour after injury in one treatment group and beginning 72 hours after injury in another group to demonstrate the method’s ability to show how and when the therapeutic drug exerts protective and/or healing effects. Fewer varicosities developed in acutely treated mice while more varicosities resolved in mice with delayed treatment. For both treatments, the drug arrested development of new axonal damage by 30 days. In addition to evaluation of therapeutics for traumatic brain injury, this hybrid microlens imaging method should be useful to study other types of brain injury and neurodegeneration and cellular responses to treatment.
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Affiliation(s)
- Chelsea D Pernici
- Center for Biomedical Engineering and Rehabilitation Sciences, Louisiana Tech University, Ruston, LA, USA
| | - Rachel K Rowe
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ, USA
| | - P Timothy Doughty
- Center for Biomedical Engineering and Rehabilitation Sciences, Louisiana Tech University, Ruston, LA, USA
| | - Mahboubeh Madadi
- Department of Marketing and Business Analytics, Lucas College of Business, San Jose State University, San Jose, CA, USA
| | - Jonathan Lifshitz
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ, USA
| | - Teresa A Murray
- Center for Biomedical Engineering and Rehabilitation Sciences, Louisiana Tech University, Ruston, LA, USA.
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10
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Maynard ME, Redell JB, Zhao J, Hood KN, Vita SM, Kobori N, Dash PK. Sarm1 loss reduces axonal damage and improves cognitive outcome after repetitive mild closed head injury. Exp Neurol 2020; 327:113207. [PMID: 31962129 DOI: 10.1016/j.expneurol.2020.113207] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/10/2020] [Accepted: 01/17/2020] [Indexed: 11/16/2022]
Abstract
One of the consistent pathologies associated with both clinical and experimental traumatic brain injury is axonal injury, especially following mild traumatic brain injury (or concussive injury). Several lines of experimental evidence have demonstrated a role for NAD+ metabolism in axonal degeneration. One of the enzymes that metabolizes NAD+ in axons is Sarm1 (Sterile Alpha and TIR Motif Containing 1), and its activity is thought to play a key role in axonal degeneration. Using a Sarm1 knock-out mouse, we examined if loss of Sarm1 offers axonal injury protection and improves cognitive outcome after repeated mild closed head injury (rmCHI). Our results indicate that rmCHI caused white matter damage that can be observed in the corpus callosum, cingulum bundle, alveus of the hippocampus, and fimbria of the fornix of wild-type mice. These pathological changes were markedly reduced in injured Sarm1-/- mice. Interestingly, the activation of astrocytes and microglia was also attenuated in the areas with white matter damage, suggesting reduced inflammation. Associated with these improved pathological outcomes, injured Sarm1-/- mice performed significantly better in both motor and cognitive tasks. Taken together, our results suggest that strategies aimed at inhibiting Sarm1 and/or restoring NAD+ levels in injured axons may have therapeutic utility.
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Affiliation(s)
- Mark E Maynard
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America
| | - John B Redell
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America
| | - Jing Zhao
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America
| | - Kimberly N Hood
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America
| | - Sydney M Vita
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America
| | - Nobuhide Kobori
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America
| | - Pramod K Dash
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School, Houston, TX 77225, United States of America.
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11
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Barretto TA, Park K, Maghen L, Park E, Kenigsberg S, Gallagher D, Liu E, Gauthier-Fisher A, Librach C, Baker A. Axon Degeneration Is Rescued with Human Umbilical Cord Perivascular Cells: A Potential Candidate for Neuroprotection After Traumatic Brain Injury. Stem Cells Dev 2019; 29:198-211. [PMID: 31701812 DOI: 10.1089/scd.2019.0135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) leads to delayed secondary injury events consisting of cellular and molecular cascades that exacerbate the initial injury. Human umbilical cord perivascular cells (HUCPVCs) secrete neurotrophic and prosurvival factors. In this study, we examined the effects of HUCPVC in sympathetic axon and cortical axon survival models and sought to determine whether HUCPVC provide axonal survival cues. We then examined the effects of the HUCPVC in an in vivo fluid percussion injury model of TBI. Our data indicate that HUCPVCs express neurotrophic and neural survival factors. They also express and secrete relevant growth and survival proteins when cultured alone, or in the presence of injured axons. Coculture experiments indicate that HUCPVCs interact preferentially with axons when cocultured with sympathetic neurons and reduce axonal degeneration. Nerve growth factor withdrawal in axonal compartments resulted in 66 ± 3% axon degeneration, whereas HUCPVC coculture rescued axon degeneration to 35 ± 3%. Inhibition of Akt (LY294002) resulted in a significant increase in degeneration compared with HUCPVC cocultures (48 ± 7% degeneration). Under normoxic conditions, control cultures showed 39 ± 5% degeneration. Oxygen glucose deprivation (OGD) resulted in 58 ± 3% degeneration and OGD HUCPVC cocultures reduced degeneration to 34 ± 5% (p < 0.05). In an in vivo model of TBI, immunohistochemical analysis of NF200 showed improved axon morphology in HUCPVC-treated animals compared with injured animals. These data presented in this study indicate an important role for perivascular cells in protecting axons from injury and a potential cell-based therapy to treat secondary injury after TBI.
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Affiliation(s)
- Tanya A Barretto
- Keenan Research Center, St. Michael's Hospital, Toronto, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Katya Park
- CReATe Fertility Center, Toronto, Canada
| | | | - Eugene Park
- Institute of Medical Science, University of Toronto, Toronto, Canada
| | | | | | - Elaine Liu
- Institute of Medical Science, University of Toronto, Toronto, Canada
| | | | - Clifford Librach
- CReATe Fertility Center, Toronto, Canada.,Department of Obstetrics and Gynecology, University of Toronto, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada.,Division of Reproductive Endocrinology and Infertility, Departments of Obstetrics and Gynecology, Sunnybrook Health Sciences Center and Women's College Hospital, Toronto, Canada
| | - Andrew Baker
- Keenan Research Center, St. Michael's Hospital, Toronto, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Critical Care, St. Michael's Hospital, Toronto, Canada.,Department of Anesthesia, University of Toronto, Toronto, Canada
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12
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Sempere L, Rodríguez-Rodríguez A, Boyero L, Egea-Guerrero J. Principales modelos experimentales de traumatismo craneoencefálico: de la preclínica a los modelos in vitro. Med Intensiva 2019; 43:362-372. [DOI: 10.1016/j.medin.2018.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 04/23/2018] [Accepted: 04/26/2018] [Indexed: 02/08/2023]
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13
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Carron SF, Yan EB, Allitt BJ, Rajan R. Immediate and Medium-term Changes in Cortical and Hippocampal Inhibitory Neuronal Populations after Diffuse TBI. Neuroscience 2018; 388:152-170. [PMID: 30036662 DOI: 10.1016/j.neuroscience.2018.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 07/09/2018] [Accepted: 07/12/2018] [Indexed: 01/09/2023]
Abstract
Changes in inhibition following traumatic brain injury (TBI) appear to be one of the major factors that contribute to excitation:inhibition imbalance. Neuron pathology, interneurons in particular evolves from minutes to weeks post injury and follows a complex time course. Previously, we showed that in the long-term in diffuse TBI (dTBI), there was select reduction of specific dendrite-targeting neurons in sensory cortex and hippocampus while in motor cortex there was up-regulation of specific dendrite-targeting neurons. We now investigated the time course of dTBI effects on interneurons in neocortex and hippocampus. Brains were labeled with antibodies against calbindin (CB), parvalbumin (PV), calretinin (CR) neuropeptide Y (NPY), and somatostatin (SOM) at 24 h and 2 weeks post dTBI. We found time-dependent, brain area-specific changes in inhibition at 24 h and 2 weeks. At 24 h post-injury, reduction of dendrite-targeting inhibitory neurons occurred in sensory cortex and hippocampus. At 2 weeks, we found compensatory changes in the somatosensory cortex and CA2/3 of hippocampus affected at 24 h, with affected interneuronal populations returning to sham levels. However, DG of hippocampus now showed reduction of dendrite-targeting inhibitory neurons. Finally, with respect to motor cortex, there was an upregulation of dendrite-targeting interneurons in the supragranular layers at 24 h returning to normal levels by 2 weeks. Overall, our findings reconfirm that dendritic inhibition is particularly susceptible to brain trauma, but also show that there are complex brain-area-specific changes in inhibitory neuronal numbers and in compensatory changes, rather than a simple monotonic progression of changes post-dTBI.
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Affiliation(s)
- Simone F Carron
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
| | - Edwin B Yan
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
| | - Benjamin J Allitt
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
| | - Ramesh Rajan
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
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14
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Lancaster MA, Meier TB, Olson DV, McCrea MA, Nelson LD, Muftuler LT. Chronic differences in white matter integrity following sport-related concussion as measured by diffusion MRI: 6-Month follow-up. Hum Brain Mapp 2018; 39:4276-4289. [PMID: 29964356 DOI: 10.1002/hbm.24245] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/19/2018] [Accepted: 05/29/2018] [Indexed: 12/24/2022] Open
Abstract
Recent studies demonstrated evidence of physiological changes in the brain following sport-related concussion (SRC) that persisted beyond the point at which athletes achieved full symptom recovery. Diffusion MRI techniques have been used to study brain white matter (WM) changes following SRC; however, longitudinal studies that follow injured athletes from the acute to chronic stages of injury are sparse. The current study explores potential persisting effects of the injury, which serves as a follow-up to our previous work that reported WM changes in the acute and subacute phase of SRC recovery. Concussed high school and collegiate football players (n = 17) and well-matched teammate controls (n = 20) were followed up at 6 months postinjury with diffusion tensor (DTI) and diffusion kurtosis imaging (DKI) as well as measures of self-reported symptoms, cognitive functioning, and balance. Results of tract-based spatial statistics (TBSS) analyses revealed continued widespread decreased mean and axial diffusivity compared to control subjects in 6-month follow-up scans. On the other hand, kurtosis metrics, which were significantly higher in concussed athletes in the acute phase, had normalized. WM tract regions-of-interest (ROIs) were created from significant clusters in the TBSS analysis, and linear mixed effects (LME) analyses were used to look at longitudinal changes in these ROIs over time. LME analyses revealed few time × group interactions indicating findings were relatively stable over time. In addition, acute concussion symptoms predicted diffusivity measures at 6 months postinjury. Findings indicate that DTI and DKI may be useful tools in assessing concussion severity, recovery, and possible long-term effects of concussion.
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Affiliation(s)
- Melissa A Lancaster
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Timothy B Meier
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Daniel V Olson
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Michael A McCrea
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Lindsay D Nelson
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - L Tugan Muftuler
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
- Center for Imaging Research Medical College of Wisconsin, Milwaukee, Wisconsin
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15
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Wang W, Zinsmaier AK, Firestone E, Lin R, Yatskievych TA, Yang S, Zhang J, Bao S. Blocking Tumor Necrosis Factor-Alpha Expression Prevents Blast-Induced Excitatory/Inhibitory Synaptic Imbalance and Parvalbumin-Positive Interneuron Loss in the Hippocampus. J Neurotrauma 2018; 35:2306-2316. [PMID: 29649942 DOI: 10.1089/neu.2018.5688] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) is a major cause of neurological disorder and death in civilian and military populations. It comprises two components-direct injury from the traumatic impact and secondary injury from ensuing neural inflammatory responses. Blocking tumor necrosis factor-alpha (TNF-α), a central regulator of neural inflammation, has been shown to improve functional recovery after TBI. However, the mechanisms underlying those therapeutic effects are still poorly understood. Here, we examined effects of 3,6'-dithiothalidomide (dTT), a potentially therapeutic TNF-α inhibitor, in mice with blast-induced TBI. We found that blast exposure resulted in elevated expression of TNF-α, activation of microglial cells, enhanced excitatory synaptic transmission, reduced inhibitory synaptic transmission, and a loss of parvalbumin-positive (PV+) inhibitory interneurons. Administration of dTT for 5 days after the blast exposure completely suppressed blast-induced increases in TNF-α transcription, largely reversed blasted-induced synaptic changes, and prevented PV+ neuron loss. However, blocking TNF-α expression by dTT failed to mitigate blast-induced microglial activation in the hippocampus, as evidenced by their non-ramified morphology. These results indicate that TNF-α plays a major role in modulating neuronal functions in blast-induced TBI and that it is a potential target for treatment of TBI-related brain disorders.
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Affiliation(s)
- Weihua Wang
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Alexander K Zinsmaier
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Ethan Firestone
- 2 Department of Otolaryngology-Head and Neck Surgery and Department of Communication Sciences and Disorders, School of Medicine, Wayne State University , Detroit, Michigan
| | - Ruizhu Lin
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona.,3 Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University , Guangzhou, China
| | - Tatiana A Yatskievych
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Sungchil Yang
- 4 Department of Biomedical Sciences, City University of Hong Kong , Kowloon, Hong Kong, China
| | - Jinsheng Zhang
- 2 Department of Otolaryngology-Head and Neck Surgery and Department of Communication Sciences and Disorders, School of Medicine, Wayne State University , Detroit, Michigan
| | - Shaowen Bao
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
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16
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Abstract
Mild traumatic brain injury (mTBI) represents a significant public healthcare concern, accounting for the majority of all head injuries. While symptoms are generally transient, some patients go on to experience long-term cognitive impairments and additional mild impacts can result in exacerbated and persisting negative outcomes. To date, studies using a range of experimental models have reported chronic behavioral deficits in the presence of axonal injury and inflammation following repeated mTBI; assessments of oxidative stress and myelin pathology have thus far been limited. However, some models employed induced acute focal damage more suggestive of moderate–severe brain injury and are therefore not relevant to repeated mTBI. Given that the nature of mechanical loading in TBI is implicated in downstream pathophysiological changes, the mechanisms of damage and chronic consequences of single and repeated closed-head mTBI remain to be fully elucidated. This review covers literature on potential mechanisms of damage following repeated mTBI, integrating known mechanisms of pathology underlying moderate–severe TBIs, with recent studies on adult rodent models relevant to direct impact injuries rather than blast-induced damage. Pathology associated with excitotoxicity and cerebral blood flow-metabolism uncoupling, oxidative stress, cell death, blood-brain barrier dysfunction, astrocyte reactivity, microglial activation, diffuse axonal injury, and dysmyelination is discussed, followed by a summary of functional deficits and preclinical assessments of therapeutic strategies. Comprehensive characterization of the pathology underlying delayed and persisting deficits following repeated mTBI is likely to facilitate further development of therapeutic strategies to limit long-term sequelae.
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Affiliation(s)
- Brooke Fehily
- 1 Experimental and Regenerative Neurosciences, School of Biological sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Melinda Fitzgerald
- 1 Experimental and Regenerative Neurosciences, School of Biological sciences, The University of Western Australia, Perth, Western Australia, Australia.,2 Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia.,3 Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute, Nedlands, Western Australia, Australia
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17
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Vascak M, Jin X, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Induces Structural and Functional Disconnection of Local Neocortical Inhibitory Networks via Parvalbumin Interneuron Diffuse Axonal Injury. Cereb Cortex 2018; 28:1625-1644. [PMID: 28334184 PMCID: PMC5907353 DOI: 10.1093/cercor/bhx058] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/20/2017] [Indexed: 12/18/2022] Open
Abstract
Diffuse axonal injury (DAI) plays a major role in cortical network dysfunction posited to cause excitatory/inhibitory imbalance after mild traumatic brain injury (mTBI). Current thought holds that white matter (WM) is uniquely vulnerable to DAI. However, clinically diagnosed mTBI is not always associated with WM DAI. This suggests an undetected neocortical pathophysiology, implicating GABAergic interneurons. To evaluate this possibility, we used mild central fluid percussion injury to generate DAI in mice with Cre-driven tdTomato labeling of parvalbumin (PV) interneurons. We followed tdTomato+ profiles using confocal and electron microscopy, together with patch-clamp analysis to probe for DAI-mediated neocortical GABAergic interneuron disruption. Within 3 h post-mTBI tdTomato+ perisomatic axonal injury (PSAI) was found across somatosensory layers 2-6. The DAI marker amyloid precursor protein colocalized with GAD67 immunoreactivity within tdTomato+ PSAI, representing the majority of GABAergic interneuron DAI. At 24 h post-mTBI, we used phospho-c-Jun, a surrogate DAI marker, for retrograde assessments of sustaining somas. Via this approach, we estimated DAI occurs in ~9% of total tdTomato+ interneurons, representing ~14% of pan-neuronal DAI. Patch-clamp recordings of tdTomato+ interneurons revealed decreased inhibitory transmission. Overall, these data show that PV interneuron DAI is a consistent and significant feature of experimental mTBI with important implications for cortical network dysfunction.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - Xiaotao Jin
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, PO Box 980709, Richmond, VA 23298-0709, USA
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18
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Moon SL, Sonenberg N, Parker R. Neuronal Regulation of eIF2α Function in Health and Neurological Disorders. Trends Mol Med 2018; 24:575-589. [PMID: 29716790 DOI: 10.1016/j.molmed.2018.04.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
Abstract
A key site of translation control is the phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α), which reduces the rate of GDP to GTP exchange by eIF2B, leading to altered translation. The extent of eIF2α phosphorylation within neurons can alter synaptic plasticity. Phosphorylation of eIF2α is triggered by four stress-responsive kinases, and as such eIF2α is often phosphorylated during neurological perturbations or disease. Moreover, in some cases decreasing eIF2α phosphorylation mitigates neurodegeneration, suggesting that this could be a therapeutic target. Mutations in the γ subunit of eIF2, the guanine exchange factor eIF2B, an eIF2α phosphatase, or in two eIF2α kinases can cause disease in humans, demonstrating the importance of proper regulation of eIF2α phosphorylation for health.
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Affiliation(s)
- Stephanie L Moon
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80303, USA.
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19
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Richter M, Negro-Demontel ML, Blanco-Ocampo D, Taranto E, Lago N, Peluffo H. Thy1-YFP-H Mice and the Parallel Rod Floor Test to Evaluate Short- and Long-Term Progression of Traumatic Brain Injury. ACTA ACUST UNITED AC 2018; 120:24.1.1-24.1.25. [PMID: 29512144 DOI: 10.1002/cpim.42] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability and is a risk factor for the later development of neuropsychiatric disorders and neurodegenerative diseases. Many models of TBI have been developed, but their further refinement and a more detailed long-term follow-up is needed. We have used the Thy1-YFP-H transgenic mouse line and the parallel rod floor test to produce an unbiased and robust method for the evaluation of the multiple effects of a validated model of controlled cortical injury. This approach reveals short- and long-term progressive changes, including compromised biphasic motor function up to 85 days post-lesion, which correlates with neuronal atrophy, dendrite and spine loss, and long-term axonal pathology evidenced by axon spheroids and fragmentation. Here we present methods for inducing a controlled cortical injury in the Thy1-YFP-H transgenic mouse line and for evaluating the resulting deficits in the parallel rod floor test. This technique constitutes a new, unbiased, and robust method for the evaluation of motor and behavioral alterations after TBI. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Monique Richter
- Neurodegeneration Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay.,Current Address: Roche Diagnostics GmbH, Penzberg, Germany
| | - María Luciana Negro-Demontel
- Neuroinflammation and Gene Therapy Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay.,Department of Histology and Embryology, Faculty of Medicine, Universidad de la República, Montevideo, Uruguay
| | - Daniela Blanco-Ocampo
- Department of Physiopathology, Faculty of Medicine, Universidad de la República, Montevideo, Uruguay
| | - Eliseo Taranto
- Department of Physiopathology, Faculty of Medicine, Universidad de la República, Montevideo, Uruguay
| | - Natalia Lago
- Neuroinflammation and Gene Therapy Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Hugo Peluffo
- Neuroinflammation and Gene Therapy Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay.,Department of Histology and Embryology, Faculty of Medicine, Universidad de la República, Montevideo, Uruguay
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20
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Vascak M, Sun J, Baer M, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Evokes Pyramidal Neuron Axon Initial Segment Plasticity and Diffuse Presynaptic Inhibitory Terminal Loss. Front Cell Neurosci 2017. [PMID: 28634442 PMCID: PMC5459898 DOI: 10.3389/fncel.2017.00157] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The axon initial segment (AIS) is the site of action potential (AP) initiation, thus a crucial regulator of neuronal activity. In excitatory pyramidal neurons, the high density of voltage-gated sodium channels (NaV1.6) at the distal AIS regulates AP initiation. A surrogate AIS marker, ankyrin-G (ankG) is a structural protein regulating neuronal functional via clustering voltage-gated ion channels. In neuronal circuits, changes in presynaptic input can alter postsynaptic output via AIS structural-functional plasticity. Recently, we showed experimental mild traumatic brain injury (mTBI) evokes neocortical circuit disruption via diffuse axonal injury (DAI) of excitatory and inhibitory neuronal systems. A key finding was that mTBI-induced neocortical electrophysiological changes involved non-DAI/ intact excitatory pyramidal neurons consistent with AIS-specific alterations. In the current study we employed Thy1-yellow fluorescent protein (YFP)-H mice to test if mTBI induces AIS structural and/or functional plasticity within intact pyramidal neurons 2 days after mTBI. We used confocal microscopy to assess intact YFP+ pyramidal neurons in layer 5 of primary somatosensory barrel field (S1BF), whose axons were continuous from the soma of origin to the subcortical white matter (SCWM). YFP+ axonal traces were superimposed on ankG and NaV1.6 immunofluorescent profiles to determine AIS position and length. We found that while mTBI had no effect on ankG start position, the length significantly decreased from the distal end, consistent with the site of AP initiation at the AIS. However, NaV1.6 structure did not change after mTBI, suggesting uncoupling from ankG. Parallel quantitative analysis of presynaptic inhibitory terminals along the postsynaptic perisomatic domain of these same intact YFP+ excitatory pyramidal neurons revealed a significant decrease in GABAergic bouton density. Also within this non-DAI population, patch-clamp recordings of intact YFP+ pyramidal neurons showed AP acceleration decreased 2 days post-mTBI, consistent with AIS functional plasticity. Simulations of realistic pyramidal neuron computational models using experimentally determined AIS lengths showed a subtle decrease is NaV1.6 density is sufficient to attenuate AP acceleration. Collectively, these findings highlight the complexity of mTBI-induced neocortical circuit disruption, involving changes in extrinsic/presynaptic inhibitory perisomatic input interfaced with intrinsic/postsynaptic intact excitatory neuron AIS output.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Jianli Sun
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Matthew Baer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
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21
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Sun J, Jacobs KM. Knockout of Cyclophilin-D Provides Partial Amelioration of Intrinsic and Synaptic Properties Altered by Mild Traumatic Brain Injury. Front Syst Neurosci 2016; 10:63. [PMID: 27489538 PMCID: PMC4951523 DOI: 10.3389/fnsys.2016.00063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 07/07/2016] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are central to cell survival and Ca2+ homeostasis due to their intracellular buffering capabilities. Mitochondrial dysfunction resulting in mitochondrial permeability transition pore (mPTP) opening has been reported after mild traumatic brain injury (mTBI). Cyclosporine A provides protection against the mPTP opening through its interaction with cyclophilin-D (CypD). A recent study has found that the extent of axonal injury after mTBI was diminished in neocortex in cyclophilin-D knockout (CypDKO) mice. Here we tested whether this CypDKO could also provide protection from the increased intrinsic and synaptic neuronal excitability previously described after mTBI in a mild central fluid percussion injury mice model. CypDKO mice were crossed with mice expressing yellow fluorescent protein (YFP) in layer V pyramidal neurons in neocortex to create CypDKO/YFP-H mice. Whole cell patch clamp recordings from axotomized (AX) and intact (IN) YFP+ layer V pyramidal neurons were made 1 and 2 days after sham or mTBI in slices from CypDKO/YFP-H mice. Both excitatory post synaptic currents (EPSCs) recorded in voltage clamp and intrinsic cellular properties, including action potential (AP), afterhyperpolarization (AHP), and depolarizing after potential (DAP) characteristics recorded in current clamp were evaluated. There was no significant difference between sham and mTBI for either spontaneous or miniature EPSC frequency, suggesting that CypDKO ameliorates excitatory synaptic abnormalities. There was a partial amelioration of intrinsic properties altered by mTBI. Alleviated were the increased slope of the AP frequency vs. injected current plot, the increased AP, AHP and DAP amplitudes. Other properties that saw a reversal that became significant in the opposite direction include the current rheobase and AP overshoot. The AP threshold remained depolarized and the input resistance remained increased in mTBI compared to sham. Additional altered properties suggest that the CypDKO likely has a direct effect on membrane properties, rather than producing a selective reduction of the effects of mTBI. These results suggest that inhibiting CypD after TBI is an effective strategy to reduce synaptic hyperexcitation, making it a continued target for potential treatment of network abnormalities.
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Affiliation(s)
- Jianli Sun
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Richmond, VA, USA
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Richmond, VA, USA
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22
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Ziebell JM, Rowe RK, Harrison JL, Eakin KC, Colburn T, Willyerd FA, Lifshitz J. Experimental diffuse brain injury results in regional alteration of gross vascular morphology independent of neuropathology. Brain Inj 2015; 30:217-24. [PMID: 26646974 DOI: 10.3109/02699052.2015.1090012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PRIMARY OBJECTIVE A dynamic relationship exists between diffuse traumatic brain injury and changes to the neurovascular unit. The purpose of this study was to evaluate vascular changes during the first week following diffuse TBI. It was hypothesized that pathology is associated with modification of the vasculature. METHODS Male Sprague-Dawley rats underwent either midline fluid percussion injury or sham-injury. Brain tissue was collected 1, 2 or 7 days post-injury or sham-injury (n = 3/time point). Tissue was collected and stained by de Olmos amino-cupric silver technique to visualize neuropathology or animals were perfused with AltaBlue casting resin before high-resolution vascular imaging. The average volume, surface area, radius, branching and tortuosity of the vessels were evaluated across three regions of interest. RESULTS In M2, average vessel volume (p < 0.01) and surface area (p < 0.05) were significantly larger at 1 day relative to 2 days, 7 days and sham. In S1BF and VPM, no significant differences in the average vessel volume or surface area at any of the post-injury time points were observed. No significant changes in average radius, branching or tortuosity were observed. CONCLUSIONS Preliminary findings suggest gross morphological changes within the vascular network likely represent an acute response to mechanical forces of injury, rather than delayed or chronic pathological processes.
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Affiliation(s)
- Jenna M Ziebell
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA
| | - Rachel K Rowe
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA.,c Phoenix VA Healthcare System , Phoenix , AZ , USA
| | - Jordan L Harrison
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA
| | - Katharine C Eakin
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA
| | - Taylor Colburn
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA
| | - F Anthony Willyerd
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA.,d Critical Care, Phoenix Children's Hospital , Phoenix , AZ , USA
| | - Jonathan Lifshitz
- a BARROW Neurological Institute at Phoenix Children's Hospital , Phoenix , AZ , USA.,b Department of Child Health , University of Arizona College of Medicine - Phoenix , Phoenix , AZ , USA.,c Phoenix VA Healthcare System , Phoenix , AZ , USA.,e Psychology , Arizona State University , Tempe , AZ , USA
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23
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Lin M, He H, Schifitto G, Zhong J. Simulation of changes in diffusion related to different pathologies at cellular level after traumatic brain injury. Magn Reson Med 2015; 76:290-300. [PMID: 26256558 DOI: 10.1002/mrm.25816] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 05/26/2015] [Indexed: 11/05/2022]
Abstract
PURPOSE The goal of the current study was to investigate tissue pathology at the cellular level in traumatic brain injury (TBI) as revealed by Monte Carlo simulation of diffusion tensor imaging (DTI)-derived parameters and elucidate the possible sources of conflicting findings of DTI abnormalities as reported in the TBI literature. METHODS A model with three compartments separated by permeable membranes was employed to represent the diffusion environment of water molecules in brain white matter. The dynamic diffusion process was simulated with a Monte Carlo method using adjustable parameters of intra-axonal diffusivity, axon separation, glial cell volume fraction, and myelin sheath permeability. The effects of tissue pathology on DTI parameters were investigated by adjusting the parameters of the model corresponding to different stages of brain injury. RESULTS The results suggest that the model is appropriate and the DTI-derived parameters simulate the predominant cellular pathology after TBI. Our results further indicate that when edema is not prevalent, axial and radial diffusivity have better sensitivity to axonal injury and demyelination than other DTI parameters. CONCLUSION DTI is a promising biomarker to detect and stage tissue injury after TBI. The observed inconsistencies among previous studies are likely due to scanning at different stages of tissue injury after TBI. Magn Reson Med 76:290-300, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Mu Lin
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongjian He
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Giovanni Schifitto
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA.,Department of Imaging Sciences, University of Rochester Medical Center, Rochester, New York, USA
| | - Jianhui Zhong
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Imaging Sciences, University of Rochester Medical Center, Rochester, New York, USA
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24
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Abstract
Since the original descriptions of postconcussive pathophysiology, there has been a significant increase in interest and ongoing research to study the biological underpinnings of concussion. The initial ionic flux and glutamate release result in significant energy demands and a period of metabolic crisis for the injured brain. These physiological perturbations can now be linked to clinical characteristics of concussion, including migrainous symptoms, vulnerability to repeat injury, and cognitive impairment. Furthermore, advanced neuroimaging now allows a research window to monitor postconcussion pathophysiology in humans noninvasively. There is also increasing concern about the risk for chronic or even progressive neurobehavioral impairment after concussion/mild traumatic brain injury. Critical studies are underway to better link the acute pathobiology of concussion with potential mechanisms of chronic cell death, dysfunction, and neurodegeneration. This "new and improved" article summarizes in a translational fashion and updates what is known about the acute neurometabolic changes after concussive brain injury. Furthermore, new connections are proposed between this neurobiology and early clinical symptoms as well as to cellular processes that may underlie long-term impairment.
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Affiliation(s)
- Christopher C Giza
- *Division of Pediatric Neurology, Department of Pediatrics, Mattel Children's Hospital-UCLA, Los Angeles, California; ‡Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California; §Interdepartmental Programs for Neuroscience and Biomedical Engineering, UCLA, Los Angeles, California; ¶Department of Medical and Molecular Pharmacology, UCLA, Los Angeles, California
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Xu L, Ryu J, Hiel H, Menon A, Aggarwal A, Rha E, Mahairaki V, Cummings BJ, Koliatsos VE. Transplantation of human oligodendrocyte progenitor cells in an animal model of diffuse traumatic axonal injury: survival and differentiation. Stem Cell Res Ther 2015; 6:93. [PMID: 25971252 PMCID: PMC4453242 DOI: 10.1186/s13287-015-0087-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/13/2015] [Accepted: 05/01/2015] [Indexed: 12/14/2022] Open
Abstract
Introduction Diffuse axonal injury is an extremely common type of traumatic brain injury encountered in motor vehicle crashes, sports injuries, and in combat. Although many cases of diffuse axonal injury result in chronic disability, there are no current treatments for this condition. Its basic lesion, traumatic axonal injury, has been aggressively modeled in primate and rodent animal models. The inexorable axonal and perikaryal degeneration and dysmyelination often encountered in traumatic axonal injury calls for regenerative therapies, including therapies based on stem cells and precursors. Here we explore the proof of concept that treatments based on transplants of human oligodendrocyte progenitor cells can replace or remodel myelin and, eventually, contribute to axonal regeneration in traumatic axonal injury. Methods We derived human oligodendrocyte progenitor cells from the human embryonic stem cell line H9, purified and characterized them. We then transplanted these human oligodendrocyte progenitor cells into the deep sensorimotor cortex next to the corpus callosum of nude rats subjected to traumatic axonal injury based on the impact acceleration model of Marmarou. We explored the time course and spatial distribution of differentiation and structural integration of these cells in rat forebrain. Results At the time of transplantation, over 90 % of human oligodendrocyte progenitor cells expressed A2B5, PDGFR, NG2, O4, Olig2 and Sox10, a profile consistent with their progenitor or early oligodendrocyte status. After transplantation, these cells survived well and migrated massively via the corpus callosum in both injured and uninjured brains. Human oligodendrocyte progenitor cells displayed a striking preference for white matter tracts and were contained almost exclusively in the corpus callosum and external capsule, the striatopallidal striae, and cortical layer 6. Over 3 months, human oligodendrocyte progenitor cells progressively matured into myelin basic protein(+) and adenomatous polyposis coli protein(+) oligodendrocytes. The injured environment in the corpus callosum of impact acceleration subjects tended to favor maturation of human oligodendrocyte progenitor cells. Electron microscopy revealed that mature transplant-derived oligodendrocytes ensheathed host axons with spiral wraps intimately associated with myelin sheaths. Conclusions Our findings suggest that, instead of differentiating locally, human oligodendrocyte progenitor cells migrate massively along white matter tracts and differentiate extensively into ensheathing oligodendrocytes. These features make them appealing candidates for cellular therapies of diffuse axonal injury aiming at myelin remodeling and axonal protection or regeneration. Electronic supplementary material The online version of this article (doi:10.1186/s13287-015-0087-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leyan Xu
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Jiwon Ryu
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Hakim Hiel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Adarsh Menon
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Ayushi Aggarwal
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Elizabeth Rha
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Vasiliki Mahairaki
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Brian J Cummings
- Departments of Physical and Medical Rehabilitation, Neurological Surgery, and Anatomy and Neurobiology, Sue and Bill Gross Stem Cell Research Center, Institute for Memory Impairments and Neurological Disorders, University of California at Irvine, Irvine, CA, 92697, USA.
| | - Vassilis E Koliatsos
- Division of Neuropathology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Merlo L, Cimino F, Angileri FF, La Torre D, Conti A, Cardali SM, Saija A, Germanò A. Alteration in synaptic junction proteins following traumatic brain injury. J Neurotrauma 2015; 31:1375-85. [PMID: 24661152 DOI: 10.1089/neu.2014.3385] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Extensive research and scientific efforts have been focused on the elucidation of the pathobiology of cellular and axonal damage following traumatic brain injury (TBI). Conversely, few studies have specifically addressed the issue of synaptic dysfunction. Synaptic junction proteins may be involved in post-TBI alterations, leading to synaptic loss or disrupted plasticity. A Synapse Protein Database on synapse ontology identified 109 domains implicated in synaptic activities and over 5000 proteins, but few of these demonstrated to play a role in the synaptic dysfunction after TBI. These proteins are involved in neuroplasticity and neuromodulation and, most importantly, may be used as novel neuronal markers of TBI for specific intervention.
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Affiliation(s)
- Lucia Merlo
- 1 Department of Neurosciences, University of Messina , Messina, Italy
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McGinn MJ, Povlishock JT. Cellular and molecular mechanisms of injury and spontaneous recovery. HANDBOOK OF CLINICAL NEUROLOGY 2015; 127:67-87. [PMID: 25702210 DOI: 10.1016/b978-0-444-52892-6.00005-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Until recently, most have assumed that traumatic brain injury (TBI) was singularly associated with the overt destruction of brain tissue resulting in subsequent morbidity or death. More recently, experimental and clinical studies have shown that the pathobiology of TBI is more complex, involving a host of cellular and subcellular changes that impact on neuronal function and viability while also affecting vascular reactivity and the activation of multiple biological response pathways. Here we review the brain's response to injury, examining both focal and diffuse changes and their implications for post-traumatic brain dysfunction and recovery. TBI-induced neuronal dysfunction and death as well as the diffuse involvement of multiple fiber projections are discussed together with considerations of how local axonal membrane changes or channelopathy translate into local ionic dysregulation and axonal disconnection. Concomitant changes in the cerebral microcirculation are also discussed and their relationship with the parallel changes in the brain's metabolism is considered. These cellular and subcellular events occurring within neurons and their blood supply are correlated with multiple biological response modifiers evoked by generalized post-traumatic inflammation and the parallel activation of oxidative stress processes. The chapter closes with considerations of recovery following focal or diffuse injury. Evidence for dynamic brain reorganization/repair is presented, with considerations of traumatically induced circuit disruption and their progression to either adaptive or in some cases, maladaptive reorganization.
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Affiliation(s)
- Melissa J McGinn
- Department of Anatomy and Neurobiology, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, VA, USA
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, VA, USA.
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Rowe RK, Harrison JL, O'Hara BF, Lifshitz J. Recovery of neurological function despite immediate sleep disruption following diffuse brain injury in the mouse: clinical relevance to medically untreated concussion. Sleep 2014; 37:743-52. [PMID: 24899763 DOI: 10.5665/sleep.3582] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
STUDY OBJECTIVE We investigated the relationship between immediate disruption of posttraumatic sleep and functional outcome in the diffuse brain-injured mouse. DESIGN Adult male C57BL/6 mice were subjected to moderate midline fluid percussion injury (n = 65; 1.4 atm; 6-10 min righting reflex time) or sham injury (n = 44). Cohorts received either intentional sleep disruption (minimally stressful gentle handling) or no sleep disruption for 6 h following injury. Following disruption, serum corticosterone levels (enzyme-linked immunosorbent assay) and posttraumatic sleep (noninvasive piezoelectric sleep cages) were measured. For 1-7 days postinjury, sensorimotor outcome was assessed by Rotarod and a modified Neurological Severity Score (NSS). Cognitive function was measured using Novel Object Recognition (NOR) and Morris water maze (MWM) in the first week postinjury. SETTING Neurotrauma research laboratory. MEASUREMENTS AND RESULTS Disrupting posttraumatic sleep for 6 h did not affect serum corticosterone levels or functional outcome. In the hour following the first dark onset, sleep-disrupted mice exhibited a significant increase in sleep; however, this increase was not sustained and there was no rebound of lost sleep. Regardless of sleep disruption, mice showed a time-dependent improvement in Rotarod performance, with brain-injured mice having significantly shorter latencies on day 7 compared to sham. Further, brain-injured mice, regardless of sleep disruption, had significantly higher NSS scores postinjury compared with sham. Cognitive behavioral testing showed no group differences among any treatment group measured by MWM and NOR. CONCLUSION Short-duration disruption of posttraumatic sleep did not affect functional outcome, measured by motor and cognitive performance. These data raise uncertainty about posttraumatic sleep as a mechanism of recovery from diffuse brain injury.
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Affiliation(s)
- Rachel K Rowe
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ ; Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ ; Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky College of Medicine, Lexington, KY ; Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, Lexington, KY
| | - Jordan L Harrison
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ ; Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ ; Interdisciplinary Program in Neuroscience, Arizona State University, Phoenix, AZ
| | - Bruce F O'Hara
- Department of Biology, College of Arts and Sciences, University of Kentucky College of Medicine, Lexington, KY ; Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, Lexington, KY
| | - Jonathan Lifshitz
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ ; Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ ; Phoenix Veteran Affairs Healthcare System, Phoenix, AZ ; Interdisciplinary Program in Neuroscience, Arizona State University, Phoenix, AZ ; Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky College of Medicine, Lexington, KY
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Ma M. Role of calpains in the injury-induced dysfunction and degeneration of the mammalian axon. Neurobiol Dis 2013; 60:61-79. [PMID: 23969238 PMCID: PMC3882011 DOI: 10.1016/j.nbd.2013.08.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/17/2013] [Accepted: 08/08/2013] [Indexed: 12/21/2022] Open
Abstract
Axonal injury and degeneration, whether primary or secondary, contribute to the morbidity and mortality seen in many acquired and inherited central nervous system (CNS) and peripheral nervous system (PNS) disorders, such as traumatic brain injury, spinal cord injury, cerebral ischemia, neurodegenerative diseases, and peripheral neuropathies. The calpain family of proteases has been mechanistically linked to the dysfunction and degeneration of axons. While the direct mechanisms by which transection, mechanical strain, ischemia, or complement activation trigger intra-axonal calpain activity are likely different, the downstream effects of unregulated calpain activity may be similar in seemingly disparate diseases. In this review, a brief examination of axonal structure is followed by a focused overview of the calpain family. Finally, the mechanisms by which calpains may disrupt the axonal cytoskeleton, transport, and specialized domains (axon initial segment, nodes, and terminals) are discussed.
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Affiliation(s)
- Marek Ma
- Department of Emergency Medicine, University of Pennsylvania, Philadelphia, PA, USA; Center for Resuscitation Science, University of Pennsylvania, Philadelphia, PA, USA.
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30
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Rostami E, Davidsson J, Gyorgy A, Agoston DV, Risling M, Bellander BM. The Terminal Pathway of the Complement System Is Activated in Focal Penetrating But Not in Mild Diffuse Traumatic Brain Injury. J Neurotrauma 2013; 30:1954-65. [DOI: 10.1089/neu.2012.2583] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Elham Rostami
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Johan Davidsson
- Division of Vehicle Safety, Chalmers University of Technology, Gothenburg, Sweden
| | - Andrea Gyorgy
- Department of Anatomy, Physiology and Genetics, Uniformed Services University in Bethesda, Maryland
| | - Denes V. Agoston
- Department of Anatomy, Physiology and Genetics, Uniformed Services University in Bethesda, Maryland
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Diffuse traumatic axonal injury in the optic nerve does not elicit retinal ganglion cell loss. J Neuropathol Exp Neurol 2013; 72:768-81. [PMID: 23860030 DOI: 10.1097/nen.0b013e31829d8d9d] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Much of the morbidity after traumatic brain injury (TBI) is associated with traumatic axonal injury (TAI). Although most TAI studies focus on corpus callosum white matter, the visual system has received increased interest. To assess visual system TAI, we developed a mouse model of optic nerve TAI. It is unknown, however, whether this TAI causes retinal ganglion cell (RGC) death. To address this issue, YFP (yellow fluorescent protein)-16 transgenic mice were subjected to mild TBI and followed from 2 to 28 days. Neither TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling)-positive or cleaved caspase-3-immunoreactive RGCs were observed from 2 to 28 days after TBI. Quantification of immunoreactivity of Brn3a, an RGC marker, demonstrated no RGC loss; parallel electron microscopic analysis confirmed RGC viability. Persistent RGC survival was also consistent with the finding of reorganization in the proximal axonal segments after TAI, wherein microglia/macrophages remained inactive. In contrast, activated microglia/macrophages closely enveloped the distal disconnected, degenerating axonal segments at 7 to 28 days after injury, thereby confirming that this model consistently evoked TAI followed by disconnection. Collectively, these data provide novel insight into the evolving pathobiology associated with TAI that will form a foundation for future studies exploring TAI therapy and its downstream consequences.
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Abstract
Traumatic coma is associated with disruption of axonal pathways throughout the brain, but the specific pathways involved in humans are incompletely understood. In this study, we used high angular resolution diffusion imaging to map the connectivity of axonal pathways that mediate the 2 critical components of consciousness-arousal and awareness-in the postmortem brain of a 62-year-old woman with acute traumatic coma and in 2 control brains. High angular resolution diffusion imaging tractography guided tissue sampling in the neuropathologic analysis. High angular resolution diffusion imaging tractography demonstrated complete disruption of white matter pathways connecting brainstem arousal nuclei to the basal forebrain and thalamic intralaminar and reticular nuclei. In contrast, hemispheric arousal pathways connecting the thalamus and basal forebrain to the cerebral cortex were only partially disrupted, as were the cortical "awareness pathways." Neuropathologic examination, which used β-amyloid precursor protein and fractin immunomarkers, revealed axonal injury in the white matter of the brainstem and cerebral hemispheres that corresponded to sites of high angular resolution diffusion imaging tract disruption. Axonal injury was also present within the gray matter of the hypothalamus, thalamus, basal forebrain, and cerebral cortex. We propose that traumatic coma may be a subcortical disconnection syndrome related to the disconnection of specific brainstem arousal nuclei from the thalamus and basal forebrain.
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Mild traumatic brain injury in the mouse induces axotomy primarily within the axon initial segment. Acta Neuropathol 2013; 126:59-74. [PMID: 23595276 DOI: 10.1007/s00401-013-1119-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/08/2013] [Accepted: 04/10/2013] [Indexed: 10/27/2022]
Abstract
Traumatic axonal injury (TAI) is a consistent component of traumatic brain injury (TBI), and is associated with much of its morbidity. Increasingly, it has also been recognized as a major pathology of mild TBI (mTBI). In terms of its pathogenesis, numerous studies have investigated the susceptibility of the nodes of Ranvier, the paranode and internodal regions to TAI. The nodes of Ranvier, with their unique composition and concentration of ion channels, have been suggested as the primary site of injury, initiating a cascade of abnormalities in the related paranodal and internodal domains that lead to local axonal swellings and detachment. No investigation, however, has determined the effect of TAI upon the axon initial segment (AIS), a segment critical to regulating polarity and excitability. The current study sought to identify the susceptibility of these different axon domains to TAI within the neocortex, where each axonal domain could be simultaneously assessed. Utilizing a mouse model of mTBI, a temporal and spatial heterogeneity of axonal injury was found within the neocortical gray matter. Although axonal swellings were found in all domains along myelinated neocortical axons, the majority of TAI occurred within the AIS, which progressed without overt structural disruption of the AIS itself. The finding of primary AIS involvement has important implications regarding neuronal polarity and the fate of axotomized processes, while also raising therapeutic implications, as the mechanisms underlying such axonal injury in the AIS may be distinct from those described for nodal/paranodal injury.
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Ekmark-Lewén S, Flygt J, Kiwanuka O, Meyerson BJ, Lewén A, Hillered L, Marklund N. Traumatic axonal injury in the mouse is accompanied by a dynamic inflammatory response, astroglial reactivity and complex behavioral changes. J Neuroinflammation 2013; 10:44. [PMID: 23557178 PMCID: PMC3651302 DOI: 10.1186/1742-2094-10-44] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 03/07/2013] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Diffuse traumatic axonal injury (TAI), a common consequence of traumatic brain injury, is associated with high morbidity and mortality. Inflammatory processes may play an important role in the pathophysiology of TAI. In the central fluid percussion injury (cFPI) TAI model in mice, the neuroinflammatory and astroglial response and behavioral changes are unknown. METHODS Twenty cFPI-injured and nine sham-injured mice were used, and the neuroinflammatory and astroglial response was evaluated by immunohistochemistry at 1, 3 and 7 days post-injury. The multivariate concentric square field test (MCSF) was used to compare complex behavioral changes in mice subjected to cFPI (n = 16) or sham injury (n = 10). Data was analyzed using non-parametric statistics and principal component analysis (MCSF data). RESULTS At all post-injury time points, β-amyloid precursor protein (β-APP) immunoreactivity revealed widespread bilateral axonal injury and IgG immunostaining showed increased blood-brain barrier permeability. Using vimentin and glial fibrillary acidic protein (GFAP) immunohistochemistry, glial cell reactivity was observed in cortical regions and important white matter tracts peaking at three days post-injury. Only vimentin was increased post-injury in the internal capsule and only GFAP in the thalamus. Compared to sham-injured controls, an increased number of activated microglia (MAC-2), infiltrating neutrophils (GR-1) and T-cells (CD3) appearing one day after TAI (P<0.05 for all cell types) was observed in subcortical white matter. In the MCSF, the behavioral patterns including general activity and exploratory behavior differed between cFPI mice and sham-injured controls. CONCLUSIONS Traumatic axonal injury TAI resulted in marked bilateral astroglial and neuroinflammatory responses and complex behavioral changes. The cFPI model in mice appears suitable for the study of injury mechanisms, including neuroinflammation, and the development of treatments targeting TAI.
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Affiliation(s)
- Sara Ekmark-Lewén
- Department of Neuroscience, Division of Neurosurgery, Uppsala University, Uppsala, 751 85, Sweden
| | - Johanna Flygt
- Department of Neuroscience, Division of Neurosurgery, Uppsala University, Uppsala, 751 85, Sweden
| | - Olivia Kiwanuka
- Department of Neuroscience, Division of Neurosurgery, Uppsala University, Uppsala, 751 85, Sweden
| | - Bengt J Meyerson
- Department of Neuroscience, Division of Pharmacology, Biomedical Center, Uppsala University, Uppsala, 715 23, Sweden
| | - Anders Lewén
- Department of Neuroscience, Division of Neurosurgery, Uppsala University, Uppsala, 751 85, Sweden
| | - Lars Hillered
- Department of Neuroscience, Division of Neurosurgery, Uppsala University, Uppsala, 751 85, Sweden
| | - Niklas Marklund
- Department of Neuroscience, Division of Neurosurgery, Uppsala University, Uppsala, 751 85, Sweden
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Shi C, Flanagan SR, Samadani U. Vagus nerve stimulation to augment recovery from severe traumatic brain injury impeding consciousness: a prospective pilot clinical trial. Neurol Res 2013; 35:263-76. [PMID: 23485054 PMCID: PMC4568744 DOI: 10.1179/1743132813y.0000000167] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Traumatic brain injury (TBI) has high morbidity and mortality in both civilian and military populations. Blast and other mechanisms of TBI damage the brain by causing neurons to disconnect and atrophy. Such traumatic axonal injury can lead to persistent vegetative and minimally conscious states (VS and MCS), for which limited treatment options exist, including physical, occupational, speech, and cognitive therapies. More than 60 000 patients have received vagus nerve stimulation (VNS) for epilepsy and depression. In addition to decreased seizure frequency and severity, patients report enhanced mood, reduced daytime sleepiness independent of seizure control, increased slow wave sleep, and improved cognition, memory, and quality of life. Early stimulation of the vagus nerve accelerates the rate and extent of behavioral and cognitive recovery after fluid percussion brain injury in rats. METHODS We recently obtained Food and Drug Administration (FDA) approval for a pilot prospective randomized crossover trial to demonstrate objective improvement in clinical outcome by placement of a vagus nerve stimulator in patients who are recovering from severe TBI. Our hypothesis is that stimulation of the vagus nerve results in increased cerebral blood flow and metabolism in the forebrain, thalamus, and reticular formation, which promotes arousal and improved consciousness, thereby improving outcome after TBI resulting in MCS or VS. DISCUSSION If this study demonstrates that VNS can safely and positively impact outcome, then a larger randomized prospective crossover trial will be proposed.
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Affiliation(s)
- Chen Shi
- Department of Neurosurgery, New York University School of Medicine and NYU Langone Medical Center, 550 First Ave. New York, NY 10016
| | - Steven R. Flanagan
- Department of Rehabilitation Medicine, New York University School of Medicine and NYU Langone Medical Center, 240 E. 38 St. New York, NY 10016
| | - Uzma Samadani
- Department of Neurosurgery, New York University School of Medicine and NYU Langone Medical Center, 550 First Ave. New York, NY 10016
- Division of Neurosurgery, New York Harbor Healthcare System Manhattan Veterans Hospital, 423 E. 23 St. New York, NY 10010
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Abstract
AbstractRecent investigations into the etiology and pathogenesis of Alzheimer’s disease (AD) in the past few years have expanded to include previously unexplored and/or disconnected aspects of AD and related conditions at both the cellular and systemic levels of organization. These include how AD-associated abnormalities affect the cell cycle and neuronal differentiation state and how they recruit signal transduction, membrane trafficking and protein transcytosis mechanisms to produce a neurotoxic syndrome capable of spreading itself throughout the brain. The recent expansion of AD research into intercellular and new aspects of cellular degenerative mechanisms is causing a systemic re-evaluation of AD pathogenesis, including the roles played by well-studied elements, such as the generation of Aβ and tau protein aggregates. It is also changing our view of neurodegenerative diseases as a whole. Here we propose a conceptual framework to account for some of the emerging aspects of the role of tau in AD pathogenesis.
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Bigler ED, Maxwell WL. Neuropathology of mild traumatic brain injury: relationship to neuroimaging findings. Brain Imaging Behav 2012; 6:108-36. [PMID: 22434552 DOI: 10.1007/s11682-011-9145-0] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neuroimaging identified abnormalities associated with traumatic brain injury (TBI) are but gross indicators that reflect underlying trauma-induced neuropathology at the cellular level. This review examines how cellular pathology relates to neuroimaging findings with the objective of more closely relating how neuroimaging findings reveal underlying neuropathology. Throughout this review an attempt will be made to relate what is directly known from post-mortem microscopic and gross anatomical studies of TBI of all severity levels to the types of lesions and abnormalities observed in contemporary neuroimaging of TBI, with an emphasis on mild traumatic brain injury (mTBI). However, it is impossible to discuss the neuropathology of mTBI without discussing what occurs with more severe injury and viewing pathological changes on some continuum from the mildest to the most severe. Historical milestones in understanding the neuropathology of mTBI are reviewed along with implications for future directions in the examination of neuroimaging and neuropathological correlates of TBI.
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Affiliation(s)
- Erin D Bigler
- Department of Psychology, Brigham Young University, Provo, UT, USA.
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Aungst S, England PM, Thompson SM. Critical role of trkB receptors in reactive axonal sprouting and hyperexcitability after axonal injury. J Neurophysiol 2012; 109:813-24. [PMID: 23155176 DOI: 10.1152/jn.00869.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Traumatic brain injury (TBI) causes many long-term neurological complications. Some of these conditions, such as posttraumatic epilepsy, are characterized by increased excitability that typically arises after a latent period lasting from months to years, suggesting that slow injury-induced processes are critical. We tested the hypothesis that trkB activation promotes delayed injury-induced hyperexcitability in part by promoting reactive axonal sprouting. We modeled penetrative TBI with transection of the Schaffer collateral pathway in knock-in mice having an introduced mutation in the trkB receptor (trkB(F616A)) that renders it susceptible to inhibition by the novel small molecule 1NMPP1. We observed that trkB activation was increased in area CA3 1 day after injury and that expression of a marker of axonal growth, GAP43, was increased 7 days after lesion. Extracellular field potentials in stratum pyramidale of area CA3 in acute slices from sham-operated and lesioned mice were normal in control saline. Abnormal bursts of population spikes were observed under conditions that were mildly proconvulsive but only in slices taken from mice lesioned 7-21 days earlier and not in slices from control mice. trkB activation, GAP43 upregulation, and hyperexcitability were diminished by systemic administration of 1NMPP1 for 7 days after the lesion. Synaptic transmission from area CA3 to area CA1 recovered 7 days after lesion in untreated mice but not in mice treated with 1NMPP1. We conclude that trkB receptor activation and reactive axonal sprouting are critical factors in injury-induced hyperexcitability and may contribute to the neurological complications of TBI.
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Affiliation(s)
- Stephanie Aungst
- Department of Physiology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
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Abstract
After traumatic injury, the brain undergoes a prolonged period of degenerative change that is paradoxically accompanied by cognitive recovery. The spatiotemporal pattern of atrophy and the specific relationships of atrophy to cognitive changes are ill understood. The present study used tensor-based morphometry and neuropsychological testing to examine brain volume loss in 17 traumatic brain injury (TBI) patients and 13 controls over a 4-year period. Patients were scanned at 2 months, 1 year, and 4 years post-injury. High-dimensional warping procedures were used to create change maps of each subject's brain for each of the two intervals. TBI patients experienced volume loss in both cortical areas and white matter regions during the first interval. We also observed continuing volume loss in extensive regions of white matter during the second interval. Neuropsychological correlations indicated that cognitive tasks were associated with subsequent volume loss in task-relevant regions. The extensive volume loss in brain white matter observed well beyond the first year post-injury suggests that the injured brain remains malleable for an extended period, and the neuropsychological relationships suggest that this volume loss may be associated with subtle cognitive improvements.
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40
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Cengiz N, Oztürk G, Erdoğan E, Him A, Oğuz EK. Consequences of neurite transection in vitro. J Neurotrauma 2012; 29:2465-74. [PMID: 20121423 DOI: 10.1089/neu.2009.0947] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In order to quantify degenerative and regenerative changes and analyze the contribution of multiple factors to the outcome after neurite transection, we cultured adult mouse dorsal root ganglion neurons, and with a precise laser beam, we transected the nerve fibers they extended. Cell preparations were continuously visualized for 24 h with time-lapse microscopy. More distal cuts caused a more elongated field of degeneration, while thicker neurites degenerated faster than thinner ones. Transected neurites degenerated more if the uncut neurites of the same neuron simultaneously degenerated. If any of these uncut processes regenerated, the transected neurites underwent less degeneration. Regeneration of neurites was limited to distal cuts. Unipolar neurons had shorter regeneration than multipolar ones. Branching slowed the regenerative process, while simultaneous degeneration of uncut neurites increased it. Proximal lesions, small neuronal size, and extensive and rapid neurite degeneration were predictive of death of an injured neuron, which typically displayed necrotic rather than apoptotic form. In conclusion, this in vitro model proved useful in unmasking many new aspects and correlates of mechanically-induced neurite injury.
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Affiliation(s)
- Nurettin Cengiz
- Department of Histology and Embryology, Yüzüncü Yil University Medical School, Van, Turkey
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Mesfin MN, von Reyn CR, Mott RE, Putt ME, Meaney DF. In vitro stretch injury induces time- and severity-dependent alterations of STEP phosphorylation and proteolysis in neurons. J Neurotrauma 2012; 29:1982-98. [PMID: 22435660 DOI: 10.1089/neu.2011.2253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Striatal-enriched tyrosine phosphatase (STEP) has been identified as a component of physiological and pathophysiological signaling pathways mediated by N-methyl-d-aspartate (NMDA) receptor/calcineurin/calpain activation. Activation of these pathways produces a subsequent change in STEP isoform expression or activation via dephosphorylation. In this study, we evaluated changes in STEP phosphorylation and proteolysis in dissociated cortical neurons after sublethal and lethal mechanical injury using an in vitro stretch injury device. Sublethal stretch injury produces minimal changes in STEP phosphorylation at early time points, and increased STEP phosphorylation at 24 h that is blocked by the NMDA-receptor antagonist APV, the calcineurin-inhibitor FK506, and the sodium channel blocker tetrodotoxin. Lethal stretch injury produces rapid STEP dephosphorylation via NR2B-containing NMDA receptors, but not calcineurin, and a subsequent biphasic phosphorylation pattern. STEP(61) expression progressively increases after sublethal stretch with no change in calpain-mediated STEP(33) formation, while lethal stretch injury results in STEP(33) formation via a NR2B-containing NMDA receptor pathway within 1 h of injury. Blocking calpain activation in the initial 30 min after stretch injury increases the ratio of active STEP in cells and blocks STEP(33) formation, suggesting that STEP is an early substrate of calpain after mechanical injury. There is a strong correlation between the amount of STEP(33) formed and the degree of cell death observed after lethal stretch injury. In summary, these data demonstrate that previously characterized pathways of STEP regulation via the NMDA receptor are generally conserved in mechanical injury, and suggest that calpain-mediated cleavage of STEP(33) should be further examined as an early marker of neuronal fate after stretch injury.
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Affiliation(s)
- Mahlet N Mesfin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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Harris NG, Mironova YA, Chen SF, Richards HK, Pickard JD. Preventing flow-metabolism uncoupling acutely reduces axonal injury after traumatic brain injury. J Neurotrauma 2012; 29:1469-82. [PMID: 22321027 PMCID: PMC3335110 DOI: 10.1089/neu.2011.2161] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have previously presented evidence that the development of secondary traumatic axonal injury is related to the degree of local cerebral blood flow (LCBF) and flow-metabolism uncoupling. We have now tested the hypothesis that augmenting LCBF in the acute stages after brain injury prevents further axonal injury. Data were acquired from rats with or without acetazolamide (ACZ) that was administered immediately following controlled cortical impact injury to increase cortical LCBF. Local cerebral metabolic rate for glucose (LCMRglc) and LCBF measurements were obtained 3 h post-trauma in the same rat via ¹⁸F-fluorodeoxyglucose and ¹⁴C-iodoantipyrine co-registered autoradiographic images, and compared to the density of damaged axonal profiles in adjacent sections, and in additional groups at 24 h used to assess different populations of injured axons stereologically. ACZ treatment significantly and globally elevated LCBF twofold above untreated-injured rats at 3 h (p<0.05), but did not significantly affect LCMRglc. As a result, ipsilateral LCMRglc:LCBF ratios were reduced by twofold to sham-control levels, and the density of β-APP-stained axons at 24 h was significantly reduced in most brain regions compared to the untreated-injured group (p<0.01). Furthermore, early LCBF augmentation prevented the injury-associated increase in the number of stained axons from 3-24 h. Additional robust stereological analysis of impaired axonal transport and neurofilament compaction in the corpus callosum and cingulum underlying the injury core confirmed the amelioration of β-APP axon density, and showed a trend, but no significant effect, on RMO14-positive axons. These data underline the importance of maintaining flow-metabolism coupling immediately after injury in order to prevent further axonal injury, in at least one population of injured axons.
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Affiliation(s)
- Neil G Harris
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Box 957039, Los Angeles, CA 90095-7039, USA.
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Thomas TC, Hinzman JM, Gerhardt GA, Lifshitz J. Hypersensitive glutamate signaling correlates with the development of late-onset behavioral morbidity in diffuse brain-injured circuitry. J Neurotrauma 2012; 29:187-200. [PMID: 21939393 PMCID: PMC3261793 DOI: 10.1089/neu.2011.2091] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In diffuse brain-injured rats, robust sensory sensitivity to manual whisker stimulation develops over 1 month post-injury, comparable to agitation expressed by brain-injured individuals with overstimulation. In the rat, whisker somatosensation relies on thalamocortical glutamatergic relays between the ventral posterior medial (VPM) thalamus and barrel fields of somatosensory cortex (S1BF). Using novel glutamate-selective microelectrode arrays coupled to amperometry, we test the hypothesis that disrupted glutamatergic neurotransmission underlies the whisker sensory sensitivity associated with diffuse brain injury. We report hypersensitive glutamate neurotransmission that parallels and correlates with the development of post-traumatic sensory sensitivity. Hypersensitivity is demonstrated by significant 110% increases in VPM extracellular glutamate levels, and 100% increase in potassium-evoked glutamate release in the VPM and S1BF, with no change in glutamate clearance. Further, evoked glutamate release showed 50% greater sensitivity to a calcium channel antagonist in brain-injured over uninjured VPM. In conjunction with no changes in glutamate transporter gene expression and exogenous glutamate clearance efficiency, these data support a presynaptic origin for enduring post-traumatic circuit alterations. In the anatomically-distinct whisker circuit, the injury-induced functional alterations correlate with the development of late-onset behavioral morbidity. Effective therapies to modulate presynaptic glutamate function in diffuse-injured circuits may translate into improvements in essential brain function and behavioral performance in other brain-injured circuits in rodents and in humans.
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Affiliation(s)
- Theresa Currier Thomas
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, Kentucky
- Department of Anatomy & Neurobiology, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Jason M. Hinzman
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, Kentucky
- Department of Anatomy & Neurobiology, University of Kentucky College of Medicine, Lexington, Kentucky
- Center for Microelectrode Technology, University of Kentucky College of Medicine, Lexington, Kentucky
- Morris K. Udall Parkinson's Disease Research Center of Excellence, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Greg A. Gerhardt
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, Kentucky
- Department of Anatomy & Neurobiology, University of Kentucky College of Medicine, Lexington, Kentucky
- Center for Microelectrode Technology, University of Kentucky College of Medicine, Lexington, Kentucky
- Morris K. Udall Parkinson's Disease Research Center of Excellence, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Jonathan Lifshitz
- Spinal Cord & Brain Injury Research Center, University of Kentucky College of Medicine, Lexington, Kentucky
- Department of Anatomy & Neurobiology, University of Kentucky College of Medicine, Lexington, Kentucky
- Department of Physical Medicine & Rehabilitation, University of Kentucky College of Medicine, Lexington, Kentucky
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Lifshitz J, Lisembee AM. Neurodegeneration in the somatosensory cortex after experimental diffuse brain injury. Brain Struct Funct 2012; 217:49-61. [PMID: 21597967 PMCID: PMC3536493 DOI: 10.1007/s00429-011-0323-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
Disruption and consequent reorganization of central nervous system circuits following traumatic brain injury may manifest as functional deficits and behavioral morbidities. We previously reported axotomy and neuronal atrophy in the ventral basal (VB) complex of the thalamus, without gross degeneration after experimental diffuse brain injury in adult rats. Pathology in VB coincided with the development of late-onset aberrant behavioral responses to whisker stimulation, which lead to the current hypothesis that neurodegeneration after experimental diffuse brain injury includes the primary somatosensory barrel cortex (S1BF), which receives projection of VB neurons and mediates whisker somatosensation. Over 28 days after midline fluid percussion brain injury, argyrophilic reaction product within superficial layers and layer IV barrels at 1 day progresses into the cortex to subcortical white matter by 7 days, and selective inter-barrel septa and subcortical white matter labeling at 28 days. Cellular consequences were determined by stereological estimates of neuronal nuclear volumes and number. In all cortical layers, neuronal nuclear volumes significantly atrophied by 42-49% at 7 days compared to sham, which marginally attenuated by 28 days. Concomitantly, the number of healthy neurons was reduced by 34-45% at 7 days compared to sham, returning to control levels by 28 days. Progressive neurodegeneration, including argyrophilic reaction product and neuronal nuclear atrophy, indicates injury-induced damage and reorganization of the reciprocal thalamocortical projections that mediate whisker somatosensation. The rodent whisker barrel circuit may serve as a discrete model to evaluate the causes and consequences of circuit reorganization after diffuse brain injury.
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Affiliation(s)
- Jonathan Lifshitz
- Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center, Office B463, Biomedical and Biological Sciences Research Building, 741 S. Limestone St, Lexington, KY 40536-0509, USA.
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Wang E, Gao J, Yang Q, Parsley MO, Dunn TJ, Zhang L, DeWitt DS, Denner L, Prough DS, Wu P. Molecular mechanisms underlying effects of neural stem cells against traumatic axonal injury. J Neurotrauma 2011; 29:295-312. [PMID: 22077363 DOI: 10.1089/neu.2011.2043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
Transplantation of neural stem cells (NSCs) improves functional outcomes following traumatic brain injury (TBI). Previously we demonstrated that human NSCs (hNSCs) via releasing glial cell line-derived neurotrophic factor (GDNF), preserved cognitive function in rats following parasagittal fluid percussion. However, the underlying mechanisms remain elusive. In this study, we report that NSC grafts significantly reduce TBI-induced axonal injury in the fimbria and other brain regions by blocking abnormal accumulation of amyloid precursor protein (APP). A preliminary mass spectrometry proteomics study revealed the opposite effects of TBI and NSCs on many of the cytoskeletal proteins in the CA3 region of the hippocampus, including α-smooth muscle actin (α-SMA), the main stress fiber component. Further, Western blot and immunostaining studies confirmed that TBI significantly increased the expression of α-SMA in hippocampal neurons, whereas NSC grafts counteracted the effect of TBI. In an in vitro model, rapid stretch injury significantly shortened lengths of axons and dendrites, increased the expression of both APP and α-SMA, and induced actin aggregation, effects offset by GDNF treatment. These GDNF protective effects were reversed by a GDNF-neutralizing antibody or a specific calcineurin inhibitor, and were mimicked by a specific Rho inhibitor. In summary, we demonstrate for the first time that hNSC grafts and treatment with GDNF acutely reduce traumatic axonal injury and promote neurite outgrowth. Possible mechanisms underlying GDNF-mediated neurite protection include balancing the activity of calcineurin, whereas GDNF-induced neurite outgrowth may result from the reduction of the abnormal α-SMA expression and actin aggregation via blocking Rho signals. Our study also suggests the necessity of further exploring the roles of α-SMA in the central nervous system (CNS), which may lead to a new avenue to facilitate recovery after TBI and other injuries.
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Affiliation(s)
- Enyin Wang
- Department of Neuroscience and Cell Biology, University Of Texas Medical Branch, Galveston, Texas, USA
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Sanjith S. Traumatic axonal injury in mild to moderate head injury — an illustrated review. INDIAN JOURNAL OF NEUROTRAUMA 2011. [DOI: 10.1016/s0973-0508(11)80003-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Dinocourt C, Aungst S, Yang K, Thompson SM. Homeostatic increase in excitability in area CA1 after Schaffer collateral transection in vivo. Epilepsia 2011; 52:1656-65. [PMID: 21635239 DOI: 10.1111/j.1528-1167.2011.03113.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Epilepsy is a significant long-term consequence of traumatic brain injury (TBI) and is likely to result from multiple mechanisms. One feature that is common to many forms of TBI is denervation. We asked whether chronic partial denervation in vivo would lead to a homeostatic increase in the excitability of a denervated cell population. METHODS To answer this question, we took advantage of the unique anatomy of the hippocampus where the input to the CA1 neurons, the Schaffer collaterals, could be transected in vivo with preservation of their outputs and only minor cell death. KEY FINDINGS We observed a delayed increase in neuronal excitability, as apparent in extracellular recordings from hippocampal brain slices prepared 14 days (but not 3 days) post lesion. Although population spikes in slices from control and lesioned animals were comparable under resting conditions, application of solutions that were mildly proconvulsive (high K(+) , low Mg(2+) , low concentrations of bicuculline) produced increases in the number of population spikes in slices from lesioned rats, but not in slices from unlesioned sham controls. Denervation did not produce changes in several markers of γ-aminobutyric acid (GABA)ergic synaptic inhibition, including the number of GABAergic neurons, α1 GABA(A) receptor subunits, the vesicular GABA transporter, or miniature inhibitory postsynaptic currents. SIGNIFICANCE We conclude that chronic partial denervation does lead to a delayed homeostatic increase in neuronal excitability, and may, therefore, contribute to the long-term neurologic consequences of TBI.
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Affiliation(s)
- Céline Dinocourt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Bye N, Carron S, Han X, Agyapomaa D, Ng SY, Yan E, Rosenfeld JV, Morganti-Kossmann MC. Neurogenesis and glial proliferation are stimulated following diffuse traumatic brain injury in adult rats. J Neurosci Res 2011; 89:986-1000. [PMID: 21488090 DOI: 10.1002/jnr.22635] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 12/17/2010] [Accepted: 01/27/2011] [Indexed: 12/13/2022]
Abstract
Although increased neurogenesis has been described in rodent models of focal traumatic brain injury (TBI), the neurogenic response occurring after diffuse TBI uncomplicated by focal injury has not been examined to date, despite the pervasiveness of this distinct type of brain injury in the TBI patient population. Here we characterize multiple stages of neurogenesis following a traumatic axonal injury (TAI) model of diffuse TBI as well as the proliferative response of glial cells. TAI was induced in adult rats using an impact-acceleration model, and 5-bromo-2'-deoxyuridine (BrdU) was administered on days 1-4 posttrauma or sham operation to label mitotic cells. Using immunohistochemistry for BrdU combined with phenotype-specific markers, we found that proliferation was increased following TAI in the subventricular zone of the lateral ventricles and in the hippocampal subgranular zone, although the ultimate production of new dentate granule neurons at 8 weeks was not significantly enhanced. Also, abundant proliferating and reactive astrocytes, microglia, and polydendrocytes were detected throughout the brain following TAI, indicating that a robust glial response occurs in this model, although very few new cells in the nonneurogenic brain regions became mature neurons. We conclude that diffuse brain injury stimulates early stages of a neurogenic response similar to that described for models of focal TBI.
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Affiliation(s)
- Nicole Bye
- National Trauma Research Institute, The Alfred Hospital, Melbourne, Victoria, Australia.
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Andriessen TMJC, Jacobs B, Vos PE. Clinical characteristics and pathophysiological mechanisms of focal and diffuse traumatic brain injury. J Cell Mol Med 2011; 14:2381-92. [PMID: 20738443 PMCID: PMC3823156 DOI: 10.1111/j.1582-4934.2010.01164.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Traumatic brain injury (TBI) is a frequent and clinically highly heterogeneous neurological disorder with large socioeconomic consequences. TBI severity classification, based on the hospital admission Glasgow Coma Scale (GCS) score, ranges from mild (GCS 13-15) and moderate (GCS 9-12) to severe (GCS ≤ 8). The GCS reflects the risk of dying from TBI, which is low after mild (∼1%), intermediate after moderate (up to 15%) and high (up to 40%) after severe TBI. Intracranial damage can be focal, such as epidural and subdural haematomas and parenchymal contusions, or diffuse, for example traumatic axonal injury and diffuse cerebral oedema, although this distinction is somewhat arbitrary. Study of the cellular and molecular post-traumatic processes is essential for the understanding of TBI pathophysiology but even more to find therapeutic targets for the development of neuroprotective drugs to be eventually used in human beings. To date, studies in vitro and in vivo, mainly in animals but also in human beings, are unravelling the pathological TBI mechanisms at high pace. Nevertheless, TBI pathophysiology is all but completely elucidated. Neuroprotective treatment studies in human beings have been disappointing thus far and have not resulted in commonly accepted drugs. This review presents an overview on the clinical aspects and the pathophysiology of focal and diffuse TBI, and it highlights several acknowledged important events that occur on molecular and cellular level after TBI.
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Biomarkers associated with diffuse traumatic axonal injury: exploring pathogenesis, early diagnosis, and prognosis. ACTA ACUST UNITED AC 2011; 69:1610-8. [PMID: 21150538 DOI: 10.1097/ta.0b013e3181f5a9ed] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Diffuse traumatic axonal injury (dTAI) is a significant pathologic feature of traumatic brain injury and is associated with substantial mortality and morbidity. It is still a challenge for clinicians to make an early diagnosis of dTAI and generate accurate prognosis and direct therapeutic decisions because most patients rapidly progress to coma after trauma and because specific neurologic symptoms and focal lesions detectable with current routine imaging techniques are absent. To address these issues, many investigations have sought to identify biomarkers of dTAI. METHODS This article is a review of the pertinent medical literature. RESULTS From the perspective of the pathophysiology of dTAI, we reviewed several biomarkers that are associated with structural damage and biochemical cascades in the secondary injury or repair response to traumatic brain injury. Although some biomarkers are not specific to dTAI, they are nevertheless useful in elucidating its pathogenesis, making early diagnosis possible, predicting outcomes, and providing candidate targets for novel therapeutic strategies. CONCLUSIONS The availability of biomarker data, clinical case histories, and radiologic information can improve our current ability to diagnose and monitor pathogenic conditions and predict outcomes in patients with dTAI.
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