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Tabor J, Collins R, Debert CT, Shultz SR, Mychasiuk R. Neuroendocrine Whiplash: Slamming the Breaks on Anabolic-Androgenic Steroids Following Repetitive Mild Traumatic Brain Injury in Rats May Worsen Outcomes. Front Neurol 2019; 10:481. [PMID: 31133974 PMCID: PMC6517549 DOI: 10.3389/fneur.2019.00481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/23/2019] [Indexed: 11/13/2022] Open
Abstract
Sport-related concussion is an increasingly common injury among adolescents, with repetitive mild traumatic brain injuries (RmTBI) being a significant risk factor for long-term neurobiological and psychological consequences. It is not uncommon for younger professional athletes to consume anabolic-androgenic steroids (AAS) in an attempt to enhance their performance, subjecting their hormonally sensitive brains to potential impairment during neurodevelopment. Furthermore, RmTBI produces acute neuroendocrine dysfunction, specifically in the anterior pituitary, disrupting the hypothalamic-pituitary adrenal axis, lowering cortisol secretion that is needed to appropriately respond to injury. Some AAS users exhibit worse symptoms post-RmTBI if they quit their steroid regime. We sought to examine the pathophysiological outcomes associated with the abrupt cessation of the commonly abused AAS, Metandienone (Met) on RmTBI outcomes in rats. Prior to injury, adolescent male rats received either Met or placebo, and exercise. Rats were then administered RmTBIs or sham injuries, followed by steroid and exercise cessation (SEC) or continued treatment. A behavioral battery was conducted to measure outcomes consistent with clinical representations of post-concussion syndrome and chronic AAS exposure, followed by analysis of serum hormone levels, and qRT-PCR for mRNA expression and telomere length. RmTBI increased loss of consciousness and anxiety-like behavior, while also impairing balance and short-term working memory. SEC induced hyperactivity while Met treatment alone increased depressive-like behavior. There were cumulative effects whereby RmTBI and SEC exacerbated anxiety and short-term memory outcomes. mRNA expression in the prefrontal cortex, amygdala, hippocampus, and pituitary were modified in response to Met and SEC. Analysis of telomere length revealed the negative impact of SEC while Met and SEC produced changes in serum levels of testosterone and corticosterone. We identified robust changes in mRNA to serotonergic circuitry, neuroinflammation, and an enhanced stress response. Interestingly, Met treatment promoted glucocorticoid secretion after injury, suggesting that maintained AAS may be more beneficial than abstaining after mTBI.
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Affiliation(s)
- Jason Tabor
- Department of Psychology, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Reid Collins
- Department of Psychology, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Chantel T Debert
- Department of Psychology, University of Calgary, Calgary, AB, Canada.,Division of Physical Medicine and Rehabilitation, Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Sandy R Shultz
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Richelle Mychasiuk
- Department of Psychology, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Neuroscience, Monash University, Melbourne, VIC, Australia
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2
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Späni CB, Braun DJ, Van Eldik LJ. Sex-related responses after traumatic brain injury: Considerations for preclinical modeling. Front Neuroendocrinol 2018; 50:52-66. [PMID: 29753798 PMCID: PMC6139061 DOI: 10.1016/j.yfrne.2018.03.006] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/26/2018] [Accepted: 03/29/2018] [Indexed: 12/18/2022]
Abstract
Traumatic brain injury (TBI) has historically been viewed as a primarily male problem, since men are more likely to experience a TBI because of more frequent participation in activities that increase risk of head injuries. This male bias is also reflected in preclinical research where mostly male animals have been used in basic and translational science. However, with an aging population in which TBI incidence is increasingly sex-independent due to falls, and increasing female participation in high-risk activities, the attention to potential sex differences in TBI responses and outcomes will become more important. These considerations are especially relevant in designing preclinical animal models of TBI that are more predictive of human responses and outcomes. This review characterizes sex differences following TBI with a special emphasis on the contribution of the female sex hormones, progesterone and estrogen, to these differences. This information is potentially important in developing and customizing TBI treatments.
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Affiliation(s)
- Claudia B Späni
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY 40536, USA.
| | - David J Braun
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY 40536, USA.
| | - Linda J Van Eldik
- Sanders-Brown Center on Aging, University of Kentucky, 101 Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, B481, BBSRB, 741 S. Limestone Street, Lexington, KY 40536, USA; Department of Neuroscience, College of Medicine, University of Kentucky, UK Medical Center MN 150, Lexington, KY 40536, USA.
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3
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Abstract
Neurologic injuries of both an acute and chronic nature have been reported in the literature for various combat sport styles; however, reports of the incidence and prevalence of these injury types vary greatly. Combat sports clinicians must continue to strive for the development, implementation, and enforcement of uniform minimum requirements for brain safety. These health care providers must also seize on the honor to provide this oft-underserved population with the health care advocacy they very much deserve, but often do not receive.
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4
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Turner RC, Naser ZJ, Lucke-Wold BP, Logsdon AF, Vangilder RL, Matsumoto RR, Huber JD, Rosen CL. Single low-dose lipopolysaccharide preconditioning: neuroprotective against axonal injury and modulates glial cells. NEUROIMMUNOLOGY AND NEUROINFLAMMATION 2017; 4:6-15. [PMID: 28164149 PMCID: PMC5289820 DOI: 10.20517/2347-8659.2016.40] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aim Over 7 million traumatic brain injuries (TBI) are reported each year in the United States. However, treatments and neuroprotection following TBI are limited because secondary injury cascades are poorly understood. Lipopolysaccharide (LPS) administration before controlled cortical impact can contribute to neuroprotection. However, the underlying mechanisms and whether LPS preconditioning confers neuroprotection against closed-head injuries remains unclear. Methods The authors hypothesized that preconditioning with a low dose of LPS (0.2 mg/kg) would regulate glial reactivity and protect against diffuse axonal injury induced by weight drop. LPS was administered 7 days prior to TBI. LPS administration reduced locomotion, which recovered completely by time of injury. Results LPS preconditioning significantly reduced the post-injury gliosis response near the corpus callosum, possibly by downregulating the oncostatin M receptor. These novel findings demonstrate a protective role of LPS preconditioning against diffuse axonal injury. LPS preconditioning successfully prevented neurodegeneration near the corpus callosum, as measured by fluorojade B. Conclusion Further work is required to elucidate whether LPS preconditioning confers long-term protection against behavioral deficits and to elucidate the biochemical mechanisms responsible for LPS-induced neuroprotective effects.
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Affiliation(s)
- Ryan C Turner
- Department of Neurosurgery, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
| | - Zachary J Naser
- Department of Neurosurgery, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
| | - Brandon P Lucke-Wold
- Department of Neurosurgery, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
| | - Aric F Logsdon
- Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Department of Basic Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV 26506, USA
| | - Reyna L Vangilder
- Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Center for Health Restoration, West Virginia University, School of Nursing, Morgantown, WV 26506, USA
| | - Rae R Matsumoto
- Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Department of Basic Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV 26506, USA
| | - Jason D Huber
- Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Department of Basic Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, WV 26506, USA
| | - Charles L Rosen
- Department of Neurosurgery, West Virginia University, School of Medicine, Morgantown, WV 26506, USA; Center for Neuroscience, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
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5
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Asken BM, Sullan MJ, Snyder AR, Houck ZM, Bryant VE, Hizel LP, McLaren ME, Dede DE, Jaffee MS, DeKosky ST, Bauer RM. Factors Influencing Clinical Correlates of Chronic Traumatic Encephalopathy (CTE): a Review. Neuropsychol Rev 2016; 26:340-363. [PMID: 27561662 PMCID: PMC5507554 DOI: 10.1007/s11065-016-9327-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 08/08/2016] [Indexed: 12/14/2022]
Abstract
Chronic traumatic encephalopathy (CTE) is a neuropathologically defined disease reportedly linked to a history of repetitive brain trauma. As such, retired collision sport athletes are likely at heightened risk for developing CTE. Researchers have described distinct pathological features of CTE as well a wide range of clinical symptom presentations, recently termed traumatic encephalopathy syndrome (TES). These clinical symptoms are highly variable, non-specific to individuals described as having CTE pathology in case reports, and are often associated with many other factors. This review describes the cognitive, emotional, and behavioral changes associated with 1) developmental and demographic factors, 2) neurodevelopmental disorders, 3) normal aging, 4) adjusting to retirement, 5) drug and alcohol abuse, 6) surgeries and anesthesia, and 7) sleep difficulties, as well as the relationship between these factors and risk for developing dementia-related neurodegenerative disease. We discuss why some professional athletes may be particularly susceptible to many of these effects and the importance of choosing appropriate controls groups when designing research protocols. We conclude that these factors should be considered as modifiers predominantly of the clinical outcomes associated with repetitive brain trauma within a broader biopsychosocial framework when interpreting and attributing symptom development, though also note potential effects on neuropathological outcomes. Importantly, this could have significant treatment implications for improving quality of life.
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Affiliation(s)
- Breton M Asken
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA.
| | - Molly J Sullan
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Aliyah R Snyder
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Zachary M Houck
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Vaughn E Bryant
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Loren P Hizel
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Molly E McLaren
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Duane E Dede
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Michael S Jaffee
- Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Steven T DeKosky
- Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Russell M Bauer
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
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6
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Namjoshi DR, Cheng WH, Carr M, Martens KM, Zareyan S, Wilkinson A, McInnes KA, Cripton PA, Wellington CL. Chronic Exposure to Androgenic-Anabolic Steroids Exacerbates Axonal Injury and Microgliosis in the CHIMERA Mouse Model of Repetitive Concussion. PLoS One 2016; 11:e0146540. [PMID: 26784694 PMCID: PMC4718534 DOI: 10.1371/journal.pone.0146540] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 12/17/2015] [Indexed: 12/14/2022] Open
Abstract
Concussion is a serious health concern. Concussion in athletes is of particular interest with respect to the relationship of concussion exposure to risk of chronic traumatic encephalopathy (CTE), a neurodegenerative condition associated with altered cognitive and psychiatric functions and profound tauopathy. However, much remains to be learned about factors other than cumulative exposure that could influence concussion pathogenesis. Approximately 20% of CTE cases report a history of substance use including androgenic-anabolic steroids (AAS). How acute, chronic, or historical AAS use may affect the vulnerability of the brain to concussion is unknown. We therefore tested whether antecedent AAS exposure in young, male C57Bl/6 mice affects acute behavioral and neuropathological responses to mild traumatic brain injury (TBI) induced with the CHIMERA (Closed Head Impact Model of Engineered Rotational Acceleration) platform. Male C57Bl/6 mice received either vehicle or a cocktail of three AAS (testosterone, nandrolone and 17α-methyltestosterone) from 8-16 weeks of age. At the end of the 7th week of treatment, mice underwent two closed-head TBI or sham procedures spaced 24 h apart using CHIMERA. Post-repetitive TBI (rTBI) behavior was assessed for 7 d followed by tissue collection. AAS treatment induced the expected physiological changes including increased body weight, testicular atrophy, aggression and downregulation of brain 5-HT1B receptor expression. rTBI induced behavioral deficits, widespread axonal injury and white matter microgliosis. While AAS treatment did not worsen post-rTBI behavioral changes, AAS-treated mice exhibited significantly exacerbated axonal injury and microgliosis, indicating that AAS exposure can alter neuronal and innate immune responses to concussive TBI.
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Affiliation(s)
- Dhananjay R. Namjoshi
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Wai Hang Cheng
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Michael Carr
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kris M. Martens
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Shahab Zareyan
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Anna Wilkinson
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kurt A. McInnes
- Department of Biomechanical Engineering, University of British Columbia, Vancouver, Canada
| | - Peter A. Cripton
- Department of Biomechanical Engineering, University of British Columbia, Vancouver, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
| | - Cheryl L. Wellington
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
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7
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Turner RC, Lucke-Wold BP, Robson MJ, Lee JM, Bailes JE. Alzheimer's disease and chronic traumatic encephalopathy: Distinct but possibly overlapping disease entities. Brain Inj 2016; 30:1279-1292. [PMID: 27715315 PMCID: PMC5303562 DOI: 10.1080/02699052.2016.1193631] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE) have long been recognized as sharing some similar neuropathological features, mainly the presence of neurofibrilary tangles and hyperphosphorylated tau, but have generally been described as distinct entities. Evidence indicates that neurotrauma increases the risk of developing dementia and accelerates the progression of disease. Findings are emerging that CTE and AD may be present in the same patients. CLINICAL PRESENTATION This study presents a series of previously unpublished cases, with one case demonstrating possible neurotrauma-related AD, one pure CTE, and an example of a case exhibiting features of both AD and CTE. The future significance of this work lies not only in the confirmation of AD-CTE co-existence, but, more importantly, ways of generating a hypothesis about the possibility that CTE may accelerate AD development. Understanding the relationship between neurotrauma and neurodegenerative disease will help elucidate how distinct disease entities can co-exist in the same patient. It will ultimately require the use of pre-clinical animal models and repeat injury paradigms to investigate clinically relevant injury mechanisms. These models should produce a CTE-like phenotype that must be both neuropathologically and behaviourally similar to human disease. CONCLUSION This case series and review of the literature presents a discussion of AD and CTE in the context of neurotrauma. It highlights recent work from repetitive neurotrauma models with an emphasis on those exhibiting a CTE-like phenotype. Potential mechanisms of interest shared amongst AD and CTE are briefly addressed and future experiments are advocated for to enhance understanding of CTE pathophysiology and the relationship between CTE and AD.
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Affiliation(s)
- Ryan C. Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV 26506
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Brandon P. Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV 26506
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Matthew J. Robson
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - John M. Lee
- NorthShore Neurological Institute, NorthShore University Health System, Evanston, IL 60201
| | - Julian E. Bailes
- NorthShore Neurological Institute, NorthShore University Health System, Evanston, IL 60201
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8
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Turner RC, Lucke-Wold BP, Logsdon AF, Robson MJ, Lee JM, Bailes JE, Dashnaw ML, Huber JD, Petraglia AL, Rosen CL. Modeling Chronic Traumatic Encephalopathy: The Way Forward for Future Discovery. Front Neurol 2015; 6:223. [PMID: 26579067 PMCID: PMC4620695 DOI: 10.3389/fneur.2015.00223] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/09/2015] [Indexed: 02/05/2023] Open
Abstract
Despite the extensive media coverage associated with the diagnosis of chronic traumatic encephalopathy (CTE), our fundamental understanding of the disease pathophysiology remains in its infancy. Only recently have scientific laboratories and personnel begun to explore CTE pathophysiology through the use of preclinical models of neurotrauma. Some studies have shown the ability to recapitulate some aspects of CTE in rodent models, through the use of various neuropathological, biochemical, and/or behavioral assays. Many questions related to CTE development, however, remain unanswered. These include the role of impact severity, the time interval between impacts, the age at which impacts occur, and the total number of impacts sustained. Other important variables such as the location of impacts, character of impacts, and effect of environment/lifestyle and genetics also warrant further study. In this work, we attempt to address some of these questions by exploring work previously completed using single- and repetitive-injury paradigms. Despite some models producing some deficits similar to CTE symptoms, it is clear that further studies are required to understand the development of neuropathological and neurobehavioral features consistent with CTE-like features in rodents. Specifically, acute and chronic studies are needed that characterize the development of tau-based pathology.
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Affiliation(s)
- Ryan C. Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Brandon P. Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Aric F. Logsdon
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - Matthew J. Robson
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - John M. Lee
- Department of Pathology and Laboratory Medicine, NorthShore University Health System, University of Chicago Pritzker School of Medicine, Evanston, IL, USA
| | - Julian E. Bailes
- Department of Neurosurgery, NorthShore University Health System, University of Chicago Pritzker School of Medicine, Evanston, IL, USA
| | - Matthew L. Dashnaw
- Department of Neurosurgery, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Jason D. Huber
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | | | - Charles L. Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
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9
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Turner RC, VanGilder RL, Naser ZJ, Lucke-Wold BP, Bailes JE, Matsumoto RR, Huber JD, Rosen CL. Elucidating the severity of preclinical traumatic brain injury models: a role for functional assessment? Neurosurgery 2014; 74:382-94; discussion 394. [PMID: 24448183 PMCID: PMC4890645 DOI: 10.1227/neu.0000000000000292] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Concussion remains a symptom-based diagnosis clinically, yet preclinical studies investigating traumatic brain injury, of which concussion is believed to represent a "mild" form, emphasize histological end points with functional assessments often minimized or ignored all together. Recently, clinical studies have identified the importance of cognitive and neuropsychiatric symptoms, in addition to somatic concerns, following concussion. How these findings may translate to preclinical studies is unclear at present. OBJECTIVE To address the contrasting end points used clinically compared with those in preclinical studies and the potential role of functional assessments in a commonly used model of diffuse axonal injury (DAI). METHODS Animals were subjected to DAI by the use of the impact-acceleration model. Functional and behavioral assessments were conducted during 1 week following DAI before the completion of the histological assessment at 1 week post-DAI. RESULTS We show, despite the suggestion that this model represents concussive injury, no functional impairments as determined by using the common measures of motor, sensorimotor, cognitive, and neuropsychiatric function following injury over the course of 1 week. The lack of functional deficits is in sharp contrast to neuropathological findings indicating neural degeneration, astrocyte reactivity, and microglial activation. CONCLUSION Future studies are needed to identify functional assessments, neurophysiologic techniques, and imaging assessments more apt to distinguish differences following so-called "mild" traumatic brain injury in preclinical models and determine whether these models are truly studying concussive or subconcussive injury. These studies are needed not only to understand the mechanism of injury and production of subsequent deficits, but also to rigorously evaluate potential therapeutic agents.
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Affiliation(s)
- Ryan C. Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, West Virginia
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Reyna L. VanGilder
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Nursing, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Zachary J. Naser
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, West Virginia
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Brandon P. Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, West Virginia
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Julian E. Bailes
- Department of Neurosurgery, NorthShore University Health System, Evanston, Illinois
- Department of Neurosurgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Rae R. Matsumoto
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, West Virginia
| | - Jason D. Huber
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, West Virginia
| | - Charles L. Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, West Virginia
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
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10
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Bailes JE, Petraglia AL, Omalu BI, Nauman E, Talavage T. Role of subconcussion in repetitive mild traumatic brain injury. J Neurosurg 2013; 119:1235-45. [PMID: 23971952 DOI: 10.3171/2013.7.jns121822] [Citation(s) in RCA: 331] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Research now suggests that head impacts commonly occur during contact sports in which visible signs or symptoms of neurological dysfunction may not develop despite those impacts having the potential for neurological injury. Recent biophysics studies utilizing helmet accelerometers have indicated that athletes at the collegiate and high school levels sustain a surprisingly high number of head impacts ranging from several hundred to well over 1000 during the course of a season. The associated cumulative impact burdens over the course of a career are equally important. Clinical studies have also identified athletes with no readily observable symptoms but who exhibit functional impairment as measured by neuropsychological testing and functional MRI. Such findings have been corroborated by diffusion tensor imaging studies demonstrating axonal injury in asymptomatic athletes at the end of a season. Recent autopsy data have shown that there are subsets of athletes in contact sports who do not have a history of known or identified concussions but nonetheless have neurodegenerative pathology consistent with chronic traumatic encephalopathy. Finally, emerging laboratory data have demonstrated significant axonal injury, blood-brain barrier permeability, and evidence of neuroinflammation, all in the absence of behavioral changes. Such data suggest that subconcussive level impacts can lead to significant neurological alterations, especially if the blows are repetitive. The authors propose “subconcussion” as a significant emerging concept requiring thorough consideration of the potential role it plays in accruing sufficient anatomical and/or physiological damage in athletes and military personnel, such that the effects of these injuries are clinically expressed either contemporaneously or later in life.
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Affiliation(s)
- Julian E. Bailes
- 1Department of Neurosurgery, NorthShore University Health System, University of Chicago Pritzker School of Medicine, Evanston, Illinois
| | - Anthony L. Petraglia
- 2Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York
| | - Bennet I. Omalu
- 3Department of Pathology, University of California, Davis, California
| | - Eric Nauman
- 4School of Mechanical Engineering
- 5Weldon School of Biomedical Engineering; and
| | - Thomas Talavage
- 5Weldon School of Biomedical Engineering; and
- 6School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana
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11
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Turner RC, Lucke-Wold BP, Robson MJ, Omalu BI, Petraglia AL, Bailes JE. Repetitive traumatic brain injury and development of chronic traumatic encephalopathy: a potential role for biomarkers in diagnosis, prognosis, and treatment? Front Neurol 2012; 3:186. [PMID: 23335911 PMCID: PMC3547169 DOI: 10.3389/fneur.2012.00186] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/21/2012] [Indexed: 02/05/2023] Open
Abstract
The diagnosis of chronic traumatic encephalopathy (CTE) upon autopsy in a growing number of athletes and soldiers alike has resulted in increased awareness, by both the scientific/medical and lay communities, of the potential for lasting effects of repetitive traumatic brain injury. While the scientific community has come to better understand the clinical presentation and underlying pathophysiology of CTE, the diagnosis of CTE remains autopsy-based, which prevents adequate monitoring and tracking of the disease. The lack of established biomarkers or imaging modalities for diagnostic and prognostic purposes also prevents the development and implementation of therapeutic protocols. In this work the clinical history and pathologic findings associated with CTE are reviewed, as well as imaging modalities that have demonstrated some promise for future use in the diagnosis and/or tracking of CTE or repetitive brain injury. Biomarkers under investigation are also discussed with particular attention to the timing of release and potential utility in situations of repetitive traumatic brain injury. Further investigation into imaging modalities and biomarker elucidation for the diagnosis of CTE is clearly both needed and warranted.
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Affiliation(s)
- Ryan C. Turner
- Department of Neurosurgery, School of Medicine, West Virginia UniversityMorgantown, WV, USA
- Center for Neuroscience, School of Medicine, West Virginia UniversityMorgantown, WV, USA
- *Correspondence: Ryan C. Turner, Department of Neurosurgery, School of Medicine, West Virginia University, One Medical Center Drive, Suite 4300, Health Sciences Center, PO Box 9183, Morgantown, WV 26506-9183, USA. e-mail:
| | - Brandon P. Lucke-Wold
- Department of Neurosurgery, School of Medicine, West Virginia UniversityMorgantown, WV, USA
- Center for Neuroscience, School of Medicine, West Virginia UniversityMorgantown, WV, USA
| | - Matthew J. Robson
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia UniversityMorgantown, WV, USA
| | - Bennet I. Omalu
- Department of Pathology, University of CaliforniaDavis, CA, USA
| | - Anthony L. Petraglia
- Department of Neurosurgery, University of Rochester Medical CenterRochester, NY, USA
| | - Julian E. Bailes
- Department of Neurosurgery, NorthShore University Health SystemEvanston, IL, USA
- Section of Neurosurgery, Department of Surgery, University of Chicago Medical CenterChicago, IL, USA
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