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Criado-Marrero M, Ravi S, Bhaskar E, Barroso D, Pizzi MA, Williams L, Wellington CL, Febo M, Abisambra JF. Age dictates brain functional connectivity and axonal integrity following repetitive mild traumatic brain injuries in mice. Neuroimage 2024; 298:120764. [PMID: 39089604 DOI: 10.1016/j.neuroimage.2024.120764] [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: 04/30/2024] [Revised: 07/08/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024] Open
Abstract
Traumatic brain injuries (TBI) present a major public health challenge, demanding an in-depth understanding of age-specific symptoms and risk factors. Aging not only significantly influences brain function and plasticity but also elevates the risk of hospitalizations and death following TBIs. Repetitive mild TBIs (rmTBI) compound these issues, resulting in cumulative and long-term brain damage in the brain. In this study, we investigate the impact of age on brain network changes and white matter properties following rmTBI by employing a multi-modal approach that integrates resting-state functional magnetic resonance imaging (rsfMRI), graph theory analysis, diffusion tensor imaging (DTI), and neurite orientation dispersion and density imaging (NODDI). Our hypothesis is that the effects of rmTBI are worsened in aged animals, with this group showing more pronounced alterations in brain connectivity and white matter structure. Utilizing the closed-head impact model of engineered rotational acceleration (CHIMERA) model, we conducted rmTBIs or sham (control) procedures on young (2.5-3-months-old) and aged (22-months-old) male and female mice to model high-risk groups. Functional and structural imaging unveiled age-related reductions in communication efficiency between brain regions, while injuries induced opposhigh-risking effects on the small-world index across age groups, influencing network segregation. Functional connectivity analysis also identified alterations in 79 out of 148 brain regions by age, treatment (sham vs. rmTBI), or their interaction. Injuries exerted pronounced effects on sensory integration areas, including insular and motor cortices. Age-related disruptions in white matter integrity were observed, indicating alterations in various diffusion directions (mean diffusivity, radial diffusivity, axial diffusivity, and fractional anisotropy) and density neurite properties (dispersion index, intracellular and isotropic volume fraction). Neuroinflammation, assessed through Iba-1 and GFAP markers, correlated with higher dispersion in the optic tract, suggesting a neuroinflammatory response in injured aged animals compared to sham aged. These findings offer insight into the interplay between age, injuries, and brain connectivity, shedding light on the long-term consequences of rmTBI.
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Affiliation(s)
- Marangelie Criado-Marrero
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Sakthivel Ravi
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Ekta Bhaskar
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Department of Computer of Information Science and Engineering (CISE), University of Florida, Gainesville, FL 32610, USA
| | - Daylin Barroso
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Michael A Pizzi
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brain Injury Rehabilitation and Neuroresilience (BRAIN) Center University of Florida, Gainesville, FL 32610, USA; Department of Neurology, University of Florida, Gainesville, FL 32610, USA
| | - Lakiesha Williams
- J. Crayton Pruitt Family Department of Biomedical Engineering, Gainesville, FL 32610, USA
| | - Cheryl L Wellington
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Marcelo Febo
- McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Department of Psychiatry, University of Florida, Gainesville, FL 32610, USA; Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Jose Francisco Abisambra
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA; Brain Injury Rehabilitation and Neuroresilience (BRAIN) Center University of Florida, Gainesville, FL 32610, USA.
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Bazarian JJ, Abar B, Merchant-Borna K, Pham DL, Rozen E, Mannix R, Kawata K, Chou Y, Stephen S, Gill JM. A Pilot Study Investigating the Use of Serum Glial Fibrillary Acidic Protein to Monitor Changes in Brain White Matter Integrity After Repetitive Head Hits During a Single Collegiate Football Game. J Neurotrauma 2024; 41:1597-1608. [PMID: 38753702 DOI: 10.1089/neu.2023.0307] [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] [Indexed: 05/18/2024] Open
Abstract
Repetitive head hits (RHHs) in sports and military settings are increasingly recognized as a risk factor for adverse neurological outcomes, but they are not currently tracked. Blood-based biomarkers of concussion have recently been shown to increase after nonconcussive RHHs during a single sporting contest, raising the possibility that they could be used in real time to monitor the brain's early response to repeated asymptomatic head hits. To test this hypothesis, we measured GFAP in serum immediately before (T0), immediately after (T1) and 45 min (T2) after a single collegiate football game in 30 athletes. Glial fibrillary acidic protein (GFAP) changes were correlated with three measures of head impact exposure (number of hits, total linear acceleration, and total rotational acceleration captured by helmet impact sensors) and to changes in brain white matter (WM) integrity, estimated by regional changes in fractional anisotropy (FA) and mean diffusivity (MD) on diffusion tensor imaging from 24 h before (T1) to 48 h after (T3) the game. To account for the potentially confounding effects of physical exertion on GFAP, correlations were adjusted for kilocalories of energy expended during the game measured by wearable body sensors. All 30 participants were male with a mean age of 19.5 ± 1.2 years. No participant had a concussion during the index game. We observed a significant increase in GFAP from T0 to T1 (mean 79.69 vs. 91.95 pg/mL, p = 0.008) and from T0 to T2 (mean 79.69 vs. 99.21 pg/mL, p < 0.001). WM integrity decreased in multiple WM regions but was statistically significant in the right fornix (mean % FA change -1.43, 95% confidence interval [CI]: -2.20, -0.66). T0 to T2 increases in GFAP correlated with reduced FA in the left fornix, right fornix, and right medical meniscus and with increased MD in the right fornix (r-values ranged from 0.59 to 0.61). Adjustment for exertion had minimal effect on these correlations. GFAP changes did not correlate to head hit exposure, but after adjustment for exertion, T0 to T2 increases correlated with all three hit metrics (r-values ranged from 0.69 to 0.74). Thus, acute elevations in GFAP after a single collegiate football game of RHHs correlated with in-game head hit exposure and with reduced WM integrity 2 days later. These results suggest that GFAP may be a biologically relevant indicator of the brain's early response to RHHs during a single sporting event. Developing tools to measure the neurological response to RHHs on an individual level has the potential to provide insight into the heterogeneity in adverse outcomes after RHH exposure and for developing effective and personalized countermeasures. Owing to the small sample size, these findings should be considered preliminary; validation in a larger, independent cohort is necessary.
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Affiliation(s)
- Jeffrey J Bazarian
- Department of Emergency Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Beau Abar
- Department of Emergency Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Kian Merchant-Borna
- Department of Emergency Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Dzung L Pham
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Eric Rozen
- Department of Athletics and Recreation, University of Rochester, Rochester, New York, USA
| | - Rebekah Mannix
- Departments of Pediatrics and Emergency Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Keisuke Kawata
- Department of Kinesiology, Indiana University, Bloomington, Indiana, USA
| | - Yiyu Chou
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Steve Stephen
- University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Jessica M Gill
- Johns Hopkins School of Nursing and Medicine, Baltimore, Maryland, USA
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Orbach G, Melendes EJ, Warren K, Qiu J, Meehan WP, Mannix R, Guilhaume-Correa F. Visual Impairment in Pre-Clinical Models of Mild Traumatic Brain Injury. J Neurotrauma 2024. [PMID: 38497739 DOI: 10.1089/neu.2023.0574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024] Open
Abstract
Impairment in visual function is common after traumatic brain injury (TBI) in the clinical setting, a phenomenon that translates to pre-clinical animal models as well. In Morris et al. (2021), we reported histological changes following weight-drop-induced TBI in a rodent model including retinal ganglion cell (RGC) loss, decreased electroretinogram (ERG) evoked potential, optic nerve diameter reduction, induced inflammation and gliosis, and loss of myelin accompanied by markedly impaired visual acuity. In this review, we will describe several pre-clinical TBI models that result in injuries to the visual system, indicating that visual function may be impaired following brain injury induced by a number of different injury modalities. This underscores the importance of understanding the role of the visual system and the potential detrimental sequelae to this sensory modality post-TBI. Given that most commonly employed behavioral tests such as the Elevated Plus Maze and Morris Water Maze rely on an intact visual system, interpretation of functional deficits in diffuse models may be confounded by off- target effects on the visual system.
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Affiliation(s)
- Gabriella Orbach
- Tufts University School of Medicine, Boston, Massachusetts, USA
- Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Eva J Melendes
- Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Kaitlyn Warren
- Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Jianhua Qiu
- Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - William P Meehan
- Division of Sports Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
- The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Rebekah Mannix
- Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Fernanda Guilhaume-Correa
- Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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Borucki DM, Rohrer B, Tomlinson S. Complement propagates visual system pathology following traumatic brain injury. J Neuroinflammation 2024; 21:98. [PMID: 38632569 PMCID: PMC11022420 DOI: 10.1186/s12974-024-03098-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/10/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) is associated with the development of visual system disorders. Visual deficits can present with delay and worsen over time, and may be associated with an ongoing neuroinflammatory response that is known to occur after TBI. Complement system activation is strongly associated with the neuroinflammatory response after TBI, but whether it contributes to vision loss after TBI is unexplored. METHODS Acute and chronic neuroinflammatory changes within the dorsal lateral geniculate nucleus (dLGN) and retina were investigated subsequent to a moderate to severe murine unilateral controlled cortical impact. Neuroinflammatory and histopathological outcomes were interpreted in the context of behavioral and visual function data. To investigate the role of complement, cohorts were treated after TBI with the complement inhibitor, CR2-Crry. RESULTS At 3 days after TBI, complement component C3 was deposited on retinogeniculate synapses in the dLGN both ipsilateral and contralateral to the lesion, which was reduced in CR2-Crry treated animals. This was associated with microglia morphological changes in both the ipsilateral and contralateral dLGN, with a less ramified phenotype in vehicle compared to CR2-Crry treated animals. Microglia in vehicle treated animals also had a greater internalized VGlut2 + synaptic volume after TBI compared to CR2-Crry treated animals. Microglia morphological changes seen acutely persisted for at least 49 days after injury. Complement inhibition also reduced microglial synaptic internalization in the contralateral dLGN and increased the association between VGLUT2 and PSD95 puncta, indicating preservation of intact synapses. Unexpectedly, there were no changes in the thickness of the inner retina, retinal nerve fiber layer or retinal ganglion layer. Neuropathological changes in the dLGN were accompanied by reduced visual acuity at subacute and chronic time points after TBI, with improvement seen in CR2-Crry treated animals. CONCLUSION TBI induces complement activation within the dLGN and promotes microglial activation and synaptic internalization. Complement inhibition after TBI in a clinically relevant paradigm reduces complement activation, maintains a more surveillance-like microglia phenotype, and preserves synaptic density within the dLGN. Together, the data indicate that complement plays a key role in the development of visual deficits after TBI via complement-dependent microglial phagocytosis of synapses within the dLGN.
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Affiliation(s)
- Davis M Borucki
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Baerbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA.
- Ralph Johnson VA Medical Center, Charleston, SC, USA.
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA.
- Ralph Johnson VA Medical Center, Charleston, SC, USA.
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Boese M, Berman RY, Qiu J, Spencer HF, Radford KD, Choi KH. Effects of Mild Closed-Head Injury and Subanesthetic Ketamine Infusion on Microglia, Axonal Injury, and Synaptic Density in Sprague-Dawley Rats. Int J Mol Sci 2024; 25:4287. [PMID: 38673871 PMCID: PMC11050690 DOI: 10.3390/ijms25084287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/06/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Mild traumatic brain injury (mTBI) affects millions of people in the U.S. Approximately 20-30% of those individuals develop adverse symptoms lasting at least 3 months. In a rat mTBI study, the closed-head impact model of engineered rotational acceleration (CHIMERA) produced significant axonal injury in the optic tract (OT), indicating white-matter damage. Because retinal ganglion cells project to the lateral geniculate nucleus (LGN) in the thalamus through the OT, we hypothesized that synaptic density may be reduced in the LGN of rats following CHIMERA injury. A modified SEQUIN (synaptic evaluation and quantification by imaging nanostructure) method, combined with immunofluorescent double-labeling of pre-synaptic (synapsin) and post-synaptic (PSD-95) markers, was used to quantify synaptic density in the LGN. Microglial activation at the CHIMERA injury site was determined using Iba-1 immunohistochemistry. Additionally, the effects of ketamine, a potential neuroprotective drug, were evaluated in CHIMERA-induced mTBI. A single-session repetitive (ssr-) CHIMERA (3 impacts, 1.5 joule/impact) produced mild effects on microglial activation at the injury site, which was significantly enhanced by post-injury intravenous ketamine (10 mg/kg) infusion. However, ssr-CHIMERA did not alter synaptic density in the LGN, although ketamine produced a trend of reduction in synaptic density at post-injury day 4. Further research is necessary to characterize the effects of ssr-CHIMERA and subanesthetic doses of intravenous ketamine on different brain regions and multiple time points post-injury. The current study demonstrates the utility of the ssr-CHIMERA as a rodent model of mTBI, which researchers can use to identify biological mechanisms of mTBI and to develop improved treatment strategies for individuals suffering from head trauma.
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Affiliation(s)
- Martin Boese
- Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, Bethesda, MD 20814, USA; (M.B.); (K.D.R.)
| | - Rina Y. Berman
- Center for the Study of Traumatic Stress, Uniformed Services University, Bethesda, MD 20814, USA;
| | - Jennifer Qiu
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA;
| | - Haley F. Spencer
- Program in Neuroscience, Uniformed Services University, Bethesda, MD 20814, USA;
| | - Kennett D. Radford
- Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, Bethesda, MD 20814, USA; (M.B.); (K.D.R.)
| | - Kwang H. Choi
- Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, Bethesda, MD 20814, USA; (M.B.); (K.D.R.)
- Center for the Study of Traumatic Stress, Uniformed Services University, Bethesda, MD 20814, USA;
- Program in Neuroscience, Uniformed Services University, Bethesda, MD 20814, USA;
- Department of Psychiatry, F. E. Hébert School of Medicine, Uniformed Services University, Bethesda, MD 20814, USA
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Onicas AI, Deighton S, Yeates KO, Bray S, Graff K, Abdeen N, Beauchamp MH, Beaulieu C, Bjornson B, Craig W, Dehaes M, Deschenes S, Doan Q, Freedman SB, Goodyear BG, Gravel J, Lebel C, Ledoux AA, Zemek R, Ware AL. Longitudinal Functional Connectome in Pediatric Concussion: An Advancing Concussion Assessment in Pediatrics Study. J Neurotrauma 2024; 41:587-603. [PMID: 37489293 DOI: 10.1089/neu.2023.0183] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023] Open
Abstract
Advanced magnetic resonance imaging (MRI) techniques indicate that concussion (i.e., mild traumatic brain injury) disrupts brain structure and function in children. However, the functional connectivity of brain regions within global and local networks (i.e., functional connectome) is poorly understood in pediatric concussion. This prospective, longitudinal study addressed this gap using data from the largest neuroimaging study of pediatric concussion to date to study the functional connectome longitudinally after concussion as compared with mild orthopedic injury (OI). Children and adolescents (n = 967) 8-16.99 years with concussion or mild OI were recruited from pediatric emergency departments within 48 h post-injury. Pre-injury and 1-month post-injury symptom ratings were used to classify concussion with or without persistent symptoms based on reliable change. Subjects completed a post-acute (2-33 days) and chronic (3 or 6 months via random assignment) MRI scan. Graph theory metrics were derived from 918 resting-state functional MRI scans in 585 children (386 concussion/199 OI). Linear mixed-effects modeling was performed to assess group differences over time, correcting for multiple comparisons. Relative to OI, the global clustering coefficient was reduced at 3 months post-injury in older children with concussion and in females with concussion and persistent symptoms. Time post-injury and sex moderated group differences in local (regional) network metrics of several brain regions, including degree centrality, efficiency, and clustering coefficient of the angular gyrus, calcarine fissure, cuneus, and inferior occipital, lingual, middle occipital, post-central, and superior occipital gyrus. Relative to OI, degree centrality and nodal efficiency were reduced post-acutely, and nodal efficiency and clustering coefficient were reduced chronically after concussion (i.e., at 3 and 6 months post-injury in females; at 6 months post-injury in males). Functional network alterations were more robust and widespread chronically as opposed to post-acutely after concussion, and varied by sex, age, and symptom recovery at 1-month post-injury. Local network segregation reductions emerged globally (across the whole brain network) in older children and in females with poor recovery chronically after concussion. Reduced functioning between neighboring regions could negatively disrupt specialized information processing. Local network metric alterations were demonstrated in several posterior regions that are involved in vision and attention after concussion relative to OI. This indicates that functioning of superior parietal and occipital regions could be particularly susceptibile to the effects of concussion. Moreover, those regional alterations were especially apparent at later time periods post-injury, emerging after post-concussive symptoms resolved in most and persisted up to 6 months post-injury, and differed by biological sex. This indicates that neurobiological changes continue to occur up to 6 months after pediatric concussion, although changes emerge earlier in females than in males. Changes could reflect neural compensation mechanisms.
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Affiliation(s)
- Adrian I Onicas
- MoMiLab, IMT School for Advanced Studies Lucca, Lucca, LU, Italy
- Computer Vision Group, Sano Centre for Computational Medicine, Kraków, Poland. Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Stephanie Deighton
- Department of Psychology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Keith Owen Yeates
- Department of Psychology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Signe Bray
- Department of Radiology, Alberta Children's Hospital Research Institute, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kirk Graff
- Department of Radiology, Alberta Children's Hospital Research Institute, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nishard Abdeen
- Department of Radiology, University of Ottawa, and Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Miriam H Beauchamp
- Department of Psychology, University of Montreal and CHU Sainte-Justine Hospital Research Center, Montréal, Quebec, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Bruce Bjornson
- Division of Neurology, University of British Columbia, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - William Craig
- University of Alberta and Stollery Children's Hospital, Edmonton, Alberta, Canada
| | - Mathieu Dehaes
- Department of Radiology, Radio-oncology and Nuclear Medicine, Institute of Biomedical Engineering, University of Montreal and CHU Sainte-Justine Hospital Research Center, Montréal, Quebec, Canada
| | - Sylvain Deschenes
- Department of Radiology, Radio-oncology and Nuclear Medicine, Institute of Biomedical Engineering, University of Montreal and CHU Sainte-Justine Hospital Research Center, Montréal, Quebec, Canada
| | - Quynh Doan
- Department of Pediatrics, University of British Columbia, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Stephen B Freedman
- Departments of Pediatric and Emergency Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Bradley G Goodyear
- Department of Radiology, Alberta Children's Hospital Research Institute, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jocelyn Gravel
- Department of Department of Pediatric Emergency Medicine, University of Montreal and CHU Sainte-Justine Hospital Research Center, Montréal, Quebec, Canada
| | - Catherine Lebel
- Department of Radiology, Alberta Children's Hospital Research Institute, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrée-Anne Ledoux
- Department of Cellular and Molecular Medicine, University of Ottawa, and Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Roger Zemek
- Department of Pediatrics and Emergency Medicine, University of Ottawa, and Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Ashley L Ware
- Department of Psychology, Georgia State University, Atlanta, Georgia, USA, and Department of Neurology, University of Utah, Salt Lake City, Utah, USA
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Borucki D, Rohrer B, Tomlinson S. Complement propagates visual system pathology following traumatic brain injury. RESEARCH SQUARE 2024:rs.3.rs-3970621. [PMID: 38464312 PMCID: PMC10925413 DOI: 10.21203/rs.3.rs-3970621/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Background Traumatic brain injury (TBI) is associated with the development of visual system disorders. Visual deficits can present with delay and worsen over time, and may be associated with an ongoing neuroinflammatory response that is known to occur after TBI. Complement activation is strongly associated with the neuroinflammatory response after TBI, but whether it contributes to vision loss after TBI is unexplored. Methods Acute and chronic neuroinflammatory changes within the dorsal lateral geniculate nucleus (dLGN) and retina were investigated subsequent to murine controlled unilateral cortical impact. Neuroinflammatory and histopathological data were interpreted in the context of behavioral and visual function data. To investigate the role of complement, cohorts were treated after TBI with the complement inhibitor, CR2-Crry. Results At 3 days after TBI, complement C3 was deposited on retinogeniculate synapses in the dLGN both ipsilateral and contralateral to the lesion, which was reduced in CR2-Crry treated animals. This was associated with microglia morphological changes in both the ipsilateral and contralateral dLGN, with a more amoeboid phenotype in vehicle compared to CR2-Crry treated animals. Microglia in vehicle treated animals also had a greater internalized VGlut2+ synaptic volume after TBI compared to CR2-Crry treated animals. Microglia morphological changes seen acutely persisted for at least 49 days after injury. Complement inhibition also reduced microglial synaptic internalization in the contralateral dLGN and increased the association between VGLUT2 and PSD95 puncta, indicating preservation of intact synapses. Unexpectedly, there were no changes in the thickness of the inner retina, retinal nerve fiber layer or retinal ganglion layer. Pathologies were accompanied by reduced visual acuity at subacute and chronic time points after TBI, with improvement seen in CR2-Crry treated animals. Conclusion TBI induces complement activation within the dLGN and promotes microglial activation and synaptic internalization. Complement inhibition after TBI in a clinically relevant paradigm reduces complement activation, maintains a more surveillance-like microglia phenotype, and preserves synaptic density within the dLGN. Together, the data indicate that complement plays a key role in the development of visual deficits after TBI via complement-dependent microglial phagocytosis of synapses within the dLGN.
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Hetzer SM, O'Connell C, Lallo V, Robson M, Evanson NK. Model matters: Differential outcomes in traumatic optic neuropathy pathophysiology between blunt and blast-wave mediated head injuries. Exp Neurol 2024; 372:114613. [PMID: 37995952 PMCID: PMC10870099 DOI: 10.1016/j.expneurol.2023.114613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023]
Abstract
Over 3 million people in the United States live with long-term disability because of a traumatic brain injury (TBI). The purpose of this study was to characterize and compare two different animal models of TBI (blunt head trauma and blast TBI) to determine common and divergent characteristics of these models. With recent literature reviews noting the prevalence of visual system injury in animal models of TBI, coupled with clinical estimates of 50-75% of all TBI cases, we decided to assess commonalities, if they existed, through visual system injury. A unilateral (left directed) blast and repeat blast model injury with coup-contra-coup injury patterns were compared to a midline blunt injury. Injuries were induced in adult male mice to observe and quantify visual deficits. Retinal ganglion cell loss and axonal degeneration in the optic tract, superior colliculus, and lateral geniculate nuclei were examined to trace injury outcomes throughout major vision-associated areas. Optokinetic response, immunohistochemistry, and western blots were analyzed. Where a single blunt injury produces significant visual deficits a single blast injury appears to have less severe visual consequences. Visual deficits after repeat blasts are similar to a single blast. Single blast injury induces contralateral damage to the right optic chiasm and tract whereas bilateral injury follows a single blunt TBI. Repeat blast injuries are required to see degeneration patterns in downstream regions similar to the damage seen in a single blunt injury. This finding is further supported by amyloid precursor protein (APP) staining in injured cohorts. Blunt injured groups present with staining 1.2 mm ahead of the optic nerve, indicating axonal breakage closer to the optic chiasm. In blast groups, APP was identifiable in a bilateral pattern only in the geniculate nucleus. Evidence for unilateral neuronal degeneration in brain tissue with bilateral axonal ruptures are pivotal discoveries in this model differentiation. Analysis of the two injury models suggests that there is a significant difference in the histological outcomes dependent on injury type, though visual system injury is likely present in more cases than are currently diagnosed clinically.
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Affiliation(s)
- S M Hetzer
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, United States of America.
| | - C O'Connell
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, United States of America
| | - V Lallo
- College of Arts and Sciences, University of Cincinnati, United States of America
| | - M Robson
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, United States of America
| | - N K Evanson
- Department of Pediatrics, University of Cincinnati College of Medicine, United States of America; Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, United States of America
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Criado-Marrero M, Ravi S, Bhaskar E, Barroso D, Pizzi MA, Williams L, Wellington CL, Febo M, Abisambra JF. Age dictates brain functional connectivity and axonal integrity following repetitive mild traumatic brain injuries. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577316. [PMID: 38328104 PMCID: PMC10849649 DOI: 10.1101/2024.01.25.577316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Traumatic brain injuries (TBI) present a major public health challenge, demanding an in-depth understanding of age-specific signs and vulnerabilities. Aging not only significantly influences brain function and plasticity but also elevates the risk of hospitalizations and death following repetitive mild traumatic brain injuries (rmTBIs). In this study, we investigate the impact of age on brain network changes and white matter properties following rmTBI employing a multi-modal approach that integrates resting-state functional magnetic resonance imaging (rsfMRI), graph theory analysis, diffusion tensor imaging (DTI), and Neurite Orientation Dispersion and Density Imaging (NODDI). Utilizing the CHIMERA model, we conducted rmTBIs or sham (control) procedures on young (2.5-3 months old) and aged (22-month-old) male and female mice to model high risk groups. Functional and structural imaging unveiled age-related reductions in communication efficiency between brain regions, while injuries induced opposing effects on the small-world index across age groups, influencing network segregation. Functional connectivity analysis also identified alterations in 79 out of 148 brain regions by age, treatment (sham vs. rmTBI), or their interaction. Injuries exerted pronounced effects on sensory integration areas, including insular and motor cortices. Age-related disruptions in white matter integrity were observed, indicating alterations in various diffusion directions (mean, radial, axial diffusivity, fractional anisotropy) and density neurite properties (dispersion index, intracellular and isotropic volume fraction). Inflammation, assessed through Iba-1 and GFAP markers, correlated with higher dispersion in the optic tract, suggesting a neuroinflammatory response in aged animals. These findings provide a comprehensive understanding of the intricate interplay between age, injuries, and brain connectivity, shedding light on the long-term consequences of rmTBIs.
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10
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Zhao X, Zeng W, Xu H, Sun Z, Hu Y, Peng B, McBride JD, Duan J, Deng J, Zhang B, Kim SJ, Zoll B, Saito T, Sasaguri H, Saido TC, Ballatore C, Yao H, Wang Z, Trojanowski JQ, Brunden KR, Lee VMY, He Z. A microtubule stabilizer ameliorates protein pathogenesis and neurodegeneration in mouse models of repetitive traumatic brain injury. Sci Transl Med 2023; 15:eabo6889. [PMID: 37703352 PMCID: PMC10787216 DOI: 10.1126/scitranslmed.abo6889] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 08/24/2023] [Indexed: 09/15/2023]
Abstract
Tau pathogenesis is a hallmark of many neurodegenerative diseases, including Alzheimer's disease (AD). Although the events leading to initial tau misfolding and subsequent tau spreading in patient brains are largely unknown, traumatic brain injury (TBI) may be a risk factor for tau-mediated neurodegeneration. Using a repetitive TBI (rTBI) paradigm, we report that rTBI induced somatic accumulation of phosphorylated and misfolded tau, as well as neurodegeneration across multiple brain areas in 7-month-old tau transgenic PS19 mice but not wild-type (WT) mice. rTBI accelerated somatic tau pathology in younger PS19 mice and WT mice only after inoculation with tau preformed fibrils and AD brain-derived pathological tau (AD-tau), respectively, suggesting that tau seeds are needed for rTBI-induced somatic tau pathology. rTBI further disrupted axonal microtubules and induced punctate tau and TAR DNA binding protein 43 (TDP-43) pathology in the optic tracts of WT mice. These changes in the optic tract were associated with a decline of visual function. Treatment with a brain-penetrant microtubule-stabilizing molecule reduced rTBI-induced tau, TDP-43 pathogenesis, and neurodegeneration in the optic tract as well as visual dysfunction. Treatment with the microtubule stabilizer also alleviated rTBI-induced tau pathology in the cortices of AD-tau-inoculated WT mice. These results indicate that rTBI facilitates abnormal microtubule organization, pathological tau formation, and neurodegeneration and suggest microtubule stabilization as a potential therapeutic avenue for TBI-induced neurodegeneration.
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Affiliation(s)
- Xinyi Zhao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Wen Zeng
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Xu
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Zihan Sun
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yingxin Hu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Beibei Peng
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
| | - Jennifer D McBride
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Jiangtao Duan
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
| | - Juan Deng
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
| | - Bin Zhang
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Soo-Jung Kim
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Bryan Zoll
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Takashi Saito
- Laboratory of Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Science, Nagoya, Aichi 467-8601, Japan
| | - Hiroki Sasaguri
- Laboratory of Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
| | - Takaomi C Saido
- Laboratory of Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
| | - Carlo Ballatore
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Haishan Yao
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhaoyin Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - John Q Trojanowski
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Kurt R Brunden
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Virginia M-Y Lee
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Zhuohao He
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
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11
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McCartan R, Gratkowski A, Browning M, Hahn-Townsend C, Ferguson S, Morin A, Bachmeier C, Pearson A, Brown L, Mullan M, Crawford F, Tzekov R, Mouzon B. Human amnionic progenitor cell secretome mitigates the consequence of traumatic optic neuropathy in a mouse model. Mol Ther Methods Clin Dev 2023; 29:303-318. [PMID: 37359418 PMCID: PMC10285248 DOI: 10.1016/j.omtm.2023.04.002] [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: 01/02/2023] [Accepted: 04/12/2023] [Indexed: 06/28/2023]
Abstract
Traumatic optic neuropathy (TON) is a condition in which acute injury to the optic nerve from direct or indirect trauma results in vision loss. The most common cause of TON is indirect injury to the optic nerve caused by concussive forces that are transmitted to the optic nerve. TON occurs in up to 5% of closed-head trauma patients and there is currently no known effective treatment. One potential treatment option for TON is ST266, a cell-free biological solution containing the secretome of amnion-derived multipotent progenitor (AMP) cells. We investigated the efficacy of intranasal ST266 in a mouse model of TON induced by blunt head trauma. Injured mice treated with a 10-day regimen of ST266 showed an improvement in spatial memory and learning, a significant preservation of retinal ganglion cells, and a decrease in neuropathological markers in the optic nerve, optic tract, and dorsal lateral geniculate nucleus. ST266 treatment effectively downregulated the NLRP3 inflammasome-mediated neuroinflammation pathway after blunt trauma. Overall, treatment with ST266 was shown to improve functional and pathological outcomes in a mouse model of TON, warranting future exploration of ST266 as a cell-free therapeutic candidate for testing in all optic neuropathies.
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Affiliation(s)
- Robyn McCartan
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
- University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | | | | | | | - Scott Ferguson
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
| | - Alexander Morin
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
| | - Corbin Bachmeier
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
- Bay Pines Veterans’ Hospital, Saint Petersburg, FL 33708, USA
| | - Andrew Pearson
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
| | - Larry Brown
- Noveome Biotherapeutics, Inc., Pittsburgh, PA 15219, USA
| | - Michael Mullan
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
| | - Fiona Crawford
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
- James A. Haley Veterans’ Hospital, Tampa, FL 33612, USA
| | | | - Benoit Mouzon
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA
- James A. Haley Veterans’ Hospital, Tampa, FL 33612, USA
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12
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Torrens JN, Hetzer SM, Evanson NK. Brief Oxygen Exposure after Traumatic Brain Injury Hastens Recovery and Promotes Adaptive Chronic Endoplasmic Reticulum Stress Responses. Int J Mol Sci 2023; 24:9831. [PMID: 37372978 DOI: 10.3390/ijms24129831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Traumatic brain injury (TBI) is a major public health concern, particularly in adolescents who have a higher mortality and incidence of visual pathway injury compared to adult patients. Likewise, we have found disparities between adult and adolescent TBI outcomes in rodents. Most interestingly, adolescents suffer a prolonged apneic period immediately post-injury, leading to higher mortality; therefore, we implemented a brief oxygen exposure paradigm to circumvent this increased mortality. Adolescent male mice experienced a closed-head weight-drop TBI and were then exposed to 100% O2 until normal breathing returned or recovered in room air. We followed mice for 7 and 30 days and assessed their optokinetic response; retinal ganglion cell loss; axonal degeneration; glial reactivity; and retinal ER stress protein levels. O2 reduced adolescent mortality by 40%, improved post-injury visual acuity, and reduced axonal degeneration and gliosis in optical projection regions. ER stress protein expression was altered in injured mice, and mice given O2 utilized different ER stress pathways in a time-dependent manner. Finally, O2 exposure may be mediating these ER stress responses through regulation of the redox-sensitive ER folding protein ERO1α, which has been linked to a reduction in the toxic effects of free radicals in other animal models of ER stress.
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Affiliation(s)
- Jordyn N Torrens
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Shelby M Hetzer
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Nathan K Evanson
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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13
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Torrens JN, Hetzer SM, Evanson NK. Brief oxygen exposure after traumatic brain injury speeds recovery and promotes adaptive chronic endoplasmic reticulum stress responses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540060. [PMID: 37214818 PMCID: PMC10197672 DOI: 10.1101/2023.05.09.540060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Traumatic brain injury (TBI) is a major public health concern particularly in adolescents who have a higher mortality and incidence of visual pathway injury compared to adult patients. Likewise, we have found disparities between adult and adolescent TBI outcomes in rodents. Most interestingly, adolescents suffer a prolonged apneic period immediately post injury leading to higher mortality; so, we implemented a brief oxygen exposure paradigm to circumvent this increased mortality. Adolescent male mice experienced a closed-head weight-drop TBI then were exposed to 100% O 2 until normal breathing returned or recovered in room air. We followed mice for 7- and 30-days and assessed their optokinetic response; retinal ganglion cell loss; axonal degeneration; glial reactivity; and retinal ER stress protein levels. O 2 reduced adolescent mortality by 40%, improved post-injury visual acuity, and reduced axonal degeneration and gliosis in optic projection regions. ER stress protein expression was altered in injured mice, and mice given O 2 utilized different ER-stress pathways in a time dependent manner. Finally, O 2 exposure may be mediating these ER stress responses through regulation of the redox-sensitive ER folding protein ERO1α, which has been linked to a reduction in the toxic effects of free radicals in other animal models of ER stress.
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14
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Ryan AK, Rich W, Reilly MA. Oxidative stress in the brain and retina after traumatic injury. Front Neurosci 2023; 17:1021152. [PMID: 36816125 PMCID: PMC9935939 DOI: 10.3389/fnins.2023.1021152] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/13/2023] [Indexed: 02/05/2023] Open
Abstract
The brain and the retina share many physiological similarities, which allows the retina to serve as a model of CNS disease and disorder. In instances of trauma, the eye can even indicate damage to the brain via abnormalities observed such as irregularities in pupillary reflexes in suspected traumatic brain injury (TBI) patients. Elevation of reactive oxygen species (ROS) has been observed in neurodegenerative disorders and in both traumatic optic neuropathy (TON) and in TBI. In a healthy system, ROS play a pivotal role in cellular communication, but in neurodegenerative diseases and post-trauma instances, ROS elevation can exacerbate neurodegeneration in both the brain and the retina. Increased ROS can overwhelm the inherent antioxidant systems which are regulated via mitochondrial processes. The overabundance of ROS can lead to protein, DNA, and other forms of cellular damage which ultimately result in apoptosis. Even though elevated ROS have been observed to be a major cause in the neurodegeneration observed after TON and TBI, many antioxidants therapeutic strategies fail. In order to understand why these therapeutic approaches fail further research into the direct injury cascades must be conducted. Additional therapeutic approaches such as therapeutics capable of anti-inflammatory properties and suppression of other neurodegenerative processes may be needed for the treatment of TON, TBI, and neurodegenerative diseases.
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Affiliation(s)
- Annie K. Ryan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Wade Rich
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Matthew A. Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, United States,*Correspondence: Matthew A. Reilly,
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15
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Portillo E, Zi X, Kim Y, Tucker LB, Fu A, Miller LA, Valenzuela KS, Sullivan GM, Gauff AK, Yu F, Radomski KL, McCabe JT, Armstrong RC. Persistent hypersomnia following repetitive mild experimental traumatic brain injury: Roles of chronic stress and sex differences. J Neurosci Res 2023; 101:843-865. [PMID: 36624699 DOI: 10.1002/jnr.25165] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/15/2022] [Accepted: 12/30/2022] [Indexed: 01/11/2023]
Abstract
Traumatic brain injury (TBI) is often more complicated than a single head injury. An extreme example of this point may be military service members who experience a spectrum of exposures over a prolonged period under stressful conditions. Understanding the effects of complex exposures can inform evaluation and care to prevent persistent symptoms. We designed a longitudinal series of non-invasive procedures in adult mice to evaluate the effects of prolonged mild stress and head injury exposures. We assessed anxiety, depression, and sleep-wake dysfunction as symptoms that impact long-term outcomes after mild TBI. Unpredictable chronic mild stress (UCMS) was generated from a varied sequence of environmental stressors distributed within each of 21 days. Subsequently, mice received a mild blast combined with closed-head mild TBI on 5 days at 24-h intervals. In males and females, UCMS induced anxiety without depressive behavior. A major finding was reproducible sleep-wake dysfunction through 6- to 12-month time points in male mice that received UCMS with repetitive blast plus TBI events, or surprisingly after just UCMS alone. Specifically, male mice exhibited hypersomnia with increased sleep during the active/dark phase and fragmentation of longer wake bouts. Sleep-wake dysfunction was not found with TBI events alone, and hypersomnia was not found in females under any conditions. These results identify prolonged stress and sex differences as important considerations for sleep-wake dysfunction. Furthermore, this reproducible hypersomnia with impaired wakefulness is similar to the excessive daytime sleepiness reported in patients, including patients with TBI, which warrants further clinical screening, care, and treatment development.
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Affiliation(s)
- Edwin Portillo
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Xiaomei Zi
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Yeonho Kim
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,Preclinical Behavior and Modeling Core, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Laura B Tucker
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,Preclinical Behavior and Modeling Core, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amanda Fu
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,Preclinical Behavior and Modeling Core, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Lauren A Miller
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Krystal S Valenzuela
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Genevieve M Sullivan
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Amina K Gauff
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Fengshan Yu
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Kryslaine L Radomski
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Joseph T McCabe
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA.,Preclinical Behavior and Modeling Core, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Regina C Armstrong
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,The Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
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16
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Harris G, Rickard JJS, Butt G, Kelleher L, Blanch RJ, Cooper J, Oppenheimer PG. Review: Emerging Eye-Based Diagnostic Technologies for Traumatic Brain Injury. IEEE Rev Biomed Eng 2023; 16:530-559. [PMID: 35320105 PMCID: PMC9888755 DOI: 10.1109/rbme.2022.3161352] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 02/11/2022] [Accepted: 03/15/2022] [Indexed: 11/06/2022]
Abstract
The study of ocular manifestations of neurodegenerative disorders, Oculomics, is a growing field of investigation for early diagnostics, enabling structural and chemical biomarkers to be monitored overtime to predict prognosis. Traumatic brain injury (TBI) triggers a cascade of events harmful to the brain, which can lead to neurodegeneration. TBI, termed the "silent epidemic" is becoming a leading cause of death and disability worldwide. There is currently no effective diagnostic tool for TBI, and yet, early-intervention is known to considerably shorten hospital stays, improve outcomes, fasten neurological recovery and lower mortality rates, highlighting the unmet need for techniques capable of rapid and accurate point-of-care diagnostics, implemented in the earliest stages. This review focuses on the latest advances in the main neuropathophysiological responses and the achievements and shortfalls of TBI diagnostic methods. Validated and emerging TBI-indicative biomarkers are outlined and linked to ocular neuro-disorders. Methods detecting structural and chemical ocular responses to TBI are categorised along with prospective chemical and physical sensing techniques. Particular attention is drawn to the potential of Raman spectroscopy as a non-invasive sensing of neurological molecular signatures in the ocular projections of the brain, laying the platform for the first tangible path towards alternative point-of-care diagnostic technologies for TBI.
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Affiliation(s)
- Georgia Harris
- School of Chemical Engineering, Advanced Nanomaterials Structures and Applications Laboratories, College of Engineering and Physical SciencesUniversity of BirminghamB15 2TTBirminghamU.K.
| | - Jonathan James Stanley Rickard
- School of Chemical Engineering, Advanced Nanomaterials Structures and Applications Laboratories, College of Engineering and Physical SciencesUniversity of BirminghamB15 2TTBirminghamU.K.
- Department of Physics, Cavendish LaboratoryUniversity of CambridgeCB3 0HECambridgeU.K.
| | - Gibran Butt
- Ophthalmology DepartmentUniversity Hospitals Birmingham NHS Foundation TrustB15 2THBirminghamU.K.
| | - Liam Kelleher
- School of Chemical Engineering, Advanced Nanomaterials Structures and Applications Laboratories, College of Engineering and Physical SciencesUniversity of BirminghamB15 2TTBirminghamU.K.
| | - Richard James Blanch
- Department of Military Surgery and TraumaRoyal Centre for Defence MedicineB15 2THBirminghamU.K.
- Neuroscience and Ophthalmology, Department of Ophthalmology, University Hospitals Birmingham NHS Foundation TrustcBirminghamU.K.
| | - Jonathan Cooper
- School of Biomedical EngineeringUniversity of GlasgowG12 8LTGlasgowU.K.
| | - Pola Goldberg Oppenheimer
- School of Chemical Engineering, Advanced Nanomaterials Structures and Applications Laboratories, College of Engineering and Physical SciencesUniversity of BirminghamB15 2TTBirminghamU.K.
- Healthcare Technologies Institute, Institute of Translational MedicineB15 2THBirminghamU.K.
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17
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Chong CD, Nikolova S, Dumkrieger G, Wu T, Berisha V, Li J, Ross K, Schwedt TJ. Thalamic subfield iron accumulation after acute mild traumatic brain injury as a marker of future post-traumatic headache intensity. Headache 2023; 63:156-164. [PMID: 36651577 PMCID: PMC10184776 DOI: 10.1111/head.14446] [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: 07/20/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To explore alterations in thalamic subfield volume and iron accumulation in individuals with post-traumatic headache (PTH) relative to healthy controls. BACKGROUND The thalamus plays a pivotal role in the pathomechanism of pain and headache, yet the role of the thalamus in PTH attributed to mild traumatic brain injury (mTBI) remains unclear. METHODS A total of 107 participants underwent multimodal T1-weighted and T2* brain magnetic resonance imaging. Using a clinic-based observational study, thalamic subfield volume and thalamic iron accumulation were explored in 52 individuals with acute PTH (mean age = 41.3; standard deviation [SD] = 13.5), imaged on average 24 days post mTBI, and compared to 55 healthy controls (mean age = 38.3; SD = 11.7) without history of mTBI or migraine. Symptoms of mTBI and headache characteristics were assessed at baseline (0-59 days post mTBI) (n = 52) and 3 months later (n = 46) using the Symptom Evaluation of the Sports Concussion Assessment Tool (SCAT-5) and a detailed headache history questionnaire. RESULTS Relative to controls, individuals with acute PTH had significantly less volume in the lateral geniculate nucleus (LGN) (mean volume: PTH = 254.1, SD = 43.4 vs. controls = 278.2, SD = 39.8; p = 0.003) as well as more iron deposition in the left LGN (PTH: T2* signal = 38.6, SD = 6.5 vs. controls: T2* signal = 45.3, SD = 2.3; p = 0.048). Correlations in individuals with PTH revealed a positive relationship between left LGN T2* iron deposition and SCAT-5 symptom severity score at baseline (r = -0.29, p = 0.019) and maximum headache intensity at the 3-month follow-up (r = -0.47, p = 0.002). CONCLUSION Relative to healthy controls, individuals with acute PTH had less volume and higher iron deposition in the left LGN. Higher iron deposition in the left LGN might reflect mTBI severity and poor headache recovery.
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Affiliation(s)
- Catherine D Chong
- Department of Neurology, Mayo Clinic, Phoenix, Arizona, USA.,ASU-Mayo Center for Innovative Imaging, Phoenix, Arizona, USA
| | | | | | - Teresa Wu
- ASU-Mayo Center for Innovative Imaging, Phoenix, Arizona, USA.,School of Computing and Augmented Intelligence, Arizona State University, Tempe, Arizona, USA
| | - Visar Berisha
- ASU-Mayo Center for Innovative Imaging, Phoenix, Arizona, USA.,School of Electrical, Computer and Energy Engineering and College of Health Solutions, Arizona State University, Tempe, Arizona, USA.,College of Health Solutions, Arizona State University, Tempe, Arizona, USA
| | - Jing Li
- School of Industrial and Systems Engineering, Georgia Tech, Atlanta, Georgia, USA
| | | | - Todd J Schwedt
- Department of Neurology, Mayo Clinic, Phoenix, Arizona, USA.,ASU-Mayo Center for Innovative Imaging, Phoenix, Arizona, USA
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18
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Zhang Z, Zhang X, Wu X, Zhang Y, Lu J, Li D. Sirt1 attenuates astrocyte activation via modulating Dnajb1 and chaperone-mediated autophagy after closed head injury. Cereb Cortex 2022; 32:5191-5205. [PMID: 35106540 DOI: 10.1093/cercor/bhac007] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/04/2022] [Accepted: 01/04/2022] [Indexed: 12/27/2022] Open
Abstract
Our previous study indicates that Silent information regulator 1 (Sirt1) is involved in macroautophagy by upregulating light chain 3 (LC3) expression in astrocyte to exert a neuroprotective effect. Chaperon-mediated autophagy (CMA), another form of autophagy, is also upregulated after brain injury. However, little is known about the role of Sirt1 in regulation of the CMA. In the present study, an in vivo model of closed head injury (CHI) and an in vitro model of primary cortical astrocyte stimulated with interleukin-1β were employed to mimic the astrocyte activation induced by traumatic brain injury. Lentivirus carrying target complementary DNA (cDNA) or short hairpin RNA (shRNA) sequence was used to overexpress Sirt1 or knockdown DnaJ heat shock protein family member B1 (Dnajb1) (a molecular chaperone). We found that Sirt1 overexpression ameliorated neurological deficits, reduced tissue loss, and attenuated astrocyte activation after CHI, which was reversed by Dnajb1-shRNA administration. The upregulation of CMA activity induced by CHI in vivo and in vitro was inhibited after Dnajb1 knockdown. Sirt1 potently promoted CMA activity via upregulating Dnajb1 expression. Mechanically, Sirt1 could interact with Dnajb1 and modulate the deacetylation and ubiquitination of Dnajb1. These findings collectively suggest that Sirt1 plays a protective role against astrocyte activation, which may be associated with the regulation of the CMA activity via modulating the deacetylation and ubiquitination of Dnajb1 after CHI.
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Affiliation(s)
- Zhuo Zhang
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, P.R. China
| | - Xu Zhang
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, P.R. China
| | - Xin Wu
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, P.R. China
| | - Yan Zhang
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, P.R. China
| | - Jie Lu
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, P.R. China
| | - Dan Li
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning Province, P.R. China
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19
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Qiu J, Boucher M, Conley G, Li Y, Zhang J, Morriss N, Meehan Iii WP, Mannix R. Traumatic Brain Injury-Related Optic Nerve Damage. J Neuropathol Exp Neurol 2022; 81:344-355. [PMID: 35363316 DOI: 10.1093/jnen/nlac018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Vision disorders are associated with traumatic brain injury (TBI) in 20%-40% of clinical cases and involve a diverse set of potential symptoms that can present acutely or chronically. Due to its structure and position, the optic nerve is vulnerable to multiple forms of primary injury, which can result in traumatic optic neuropathy (TON). Multiple studies have shown that the optic tract may also be injured during TBI, though data regarding the temporospatial resolution of injury to the optic nerve are sparse. We evaluated the time course of optic nerve injury and visual impairments in our closed head impact acceleration mouse model of mild TBI (mTBI) designed to mimic repetitive injuries experienced in the context of sport. Our results show that inflammation and gliosis occur acutely in response to injury. Additionally, indications of optic nerve degeneration and functional loss of vision beginning at 1-month postinjury, and retinal ganglion cell loss at 7 months, revealed that the degeneration is continuous and permanent. Together, this study demonstrated that the optic nerve is vulnerable to damage during mTBI, which can cause TON and vision loss. These findings will be important for clinicians to consider to determine whether optic nerve is injured in the TBI patients with vision problems.
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Affiliation(s)
- Jianhua Qiu
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Masen Boucher
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Grace Conley
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Yue Li
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Neurology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jingdong Zhang
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Nicholas Morriss
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - William P Meehan Iii
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.,Division of Sports Medicine, Boston Children's Hospital, Boston, Massachusetts, USA.,The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts, USA
| | - Rebekah Mannix
- From the Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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20
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McNamara EH, Knutsen A, Korotcov A, Bosomtwi A, Liu J, Fu AH, Kostelnik C, Grillakis A, Spencer H, Dardzinski BJ, McCabe JT. Meningeal and visual pathway MRI analysis after single and repetitive Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA)-induced disruption in male and female mice. J Neurotrauma 2022; 39:784-799. [PMID: 35243900 PMCID: PMC9225425 DOI: 10.1089/neu.2021.0494] [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] [Indexed: 11/12/2022] Open
Abstract
The consequences of forceful rotational acceleration on the central nervous system are not fully understood. While traumatic brain injury (TBI) research primarily has focused on effects related to the brain parenchyma, reports of traumatic meningeal enhancement in TBI patients may possess clinical significance. The objective of this study was to evaluate the meninges and brain for changes in dynamic contrast enhancement (DCE) magnetic resonance imaging (MRI) following closed-head impact model of engineered rotational acceleration (CHIMERA)–induced cerebral insult. Adult male and female mice received one (1 × ; n = 19 CHIMERA, n = 19 Sham) or four (4 × one/day; n = 18 CHIMERA, n = 12 Sham) injuries. Each animal underwent three MRI scans: 1 week before injury, immediately after the final injury, and 1 week post-injury. Compared with baseline readings and measures in sham animals, meningeal DCE in males was increased after single impact and repetitive injury. In female mice, DCE was elevated relative to their baseline level after a single impact. One week after CHIMERA, the meningeal enhancement returned to below baseline for single injured male mice, but compared with uninjured mice remained elevated in both sexes in the multiple impact groups. Pre-DCE meningeal T2-weighted relaxation time was increased only after 1 × CHIMERA in injured mice. Since vision is impaired after CHIMERA, visual pathway regions were analyzed through imaging and glial fibrillary acidic protein (GFAP) histology. Initial DCE in the lateral geniculate nucleus (LGN) and superior colliculus (SC) and T2 increases in the optic tract (OPT) and LGN were observed after injury with decreases in DCE and T2 1 week later. Astrogliosis was apparent in the OPT and SC with increased GFAP staining 7 days post-injury. To our knowledge, this is the first study to examine meningeal integrity after CHIMERA in both male and female rodents. DCE-MRI may serve as a useful approach for pre-clinical models of meningeal injury that will enable further evaluation of the underlying mechanisms.
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Affiliation(s)
- Eileen H McNamara
- Uniformed Services University of the Health Sciences, Anatomy, Physiology & Genetics, Bethesda, Maryland, United States;
| | - Andrew Knutsen
- Henry M Jackson Foundation for the Advancement of Military Medicine Inc, 44069, Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, United States;
| | - Alexandru Korotcov
- Henry M. Jackson Foundation, Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, United States.,Uniformed Services University, Radiology & Radiological Sciences, Bethesda, Maryland, United States;
| | - Asamoah Bosomtwi
- Henry M Jackson Foundation for the Advancement of Military Medicine Inc, 44069, CNRM, 4301 Jones Bridge Road, Bethesda, Bethesda, Maryland, United States, 20814.,Uniformed Services University of the Health Sciences, 1685, Radiology & Radiological Science, 4301 Jones Bridge Road, Bethesda, Maryland, United States, 20814-4712;
| | - Jiong Liu
- Uniformed Services University of the Health Sciences, Anatomy, Physiology & Genetics, 4301 Jones Bridge Road, Bethesda, Maryland, United States, 20814-4799;
| | - Amanda H Fu
- Uniformed Services University of the Health Sciences, Anatomy, Physiology & Genetics, Bethesda, Maryland, United States;
| | - Claire Kostelnik
- Uniformed Services University of the Health Sciences, Anatomy, Physiology & Genetics, Bethesda, Maryland, United States;
| | - Antigone Grillakis
- Uniformed Services University, Anatomy, Physiology & Genetics, Bethesda, United States;
| | - Haley Spencer
- Uniformed Services University of the Health Sciences, Psychiatry, Bethesda, Maryland, United States;
| | - Bernard J Dardzinski
- Uniformed Services University of the Health Sciences, 1685, Radiology and Radiological Sciences, Bethesda, Maryland, United States;
| | - Joseph T McCabe
- Uniformed Services University of the Health Sciences, Anatomy, Physiology & Genetics, Bethesda, Maryland, United States;
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21
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Zhang Y, Li M, Yu B, Lu S, Zhang L, Zhu S, Yu Z, Xia T, Huang H, Jiang W, Zhang S, Sun L, Ye Q, Sun J, Zhu H, Huang P, Hong H, Yu S, Li W, Ai D, Fan J, Li W, Song H, Xu L, Chen X, Chen T, Zhou M, Ou J, Yang J, Li W, Hu Y, Wu W. Cold protection allows local cryotherapy in a clinical-relevant model of traumatic optic neuropathy. eLife 2022; 11:75070. [PMID: 35352678 PMCID: PMC9068221 DOI: 10.7554/elife.75070] [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: 10/28/2021] [Accepted: 03/29/2022] [Indexed: 11/24/2022] Open
Abstract
Therapeutic hypothermia (TH) is potentially an important therapy for central nervous system (CNS) trauma. However, its clinical application remains controversial, hampered by two major factors: (1) Many of the CNS injury sites, such as the optic nerve (ON), are deeply buried, preventing access for local TH. The alternative is to apply TH systemically, which significantly limits the applicable temperature range. (2) Even with possible access for 'local refrigeration', cold-induced cellular damage offsets the benefit of TH. Here we present a clinically translatable model of traumatic optic neuropathy (TON) by applying clinical trans-nasal endoscopic surgery to goats and non-human primates. This model faithfully recapitulates clinical features of TON such as the injury site (pre-chiasmatic ON), the spatiotemporal pattern of neural degeneration, and the accessibility of local treatments with large operating space. We also developed a computer program to simplify the endoscopic procedure and expand this model to other large animal species. Moreover, applying a cold-protective treatment, inspired by our previous hibernation research, enables us to deliver deep hypothermia (4 °C) locally to mitigate inflammation and metabolic stress (indicated by the transcriptomic changes after injury) without cold-induced cellular damage, and confers prominent neuroprotection both structurally and functionally. Intriguingly, neither treatment alone was effective, demonstrating that in situ deep hypothermia combined with cold protection constitutes a breakthrough for TH as a therapy for TON and other CNS traumas.
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Affiliation(s)
- Yikui Zhang
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Mengyun Li
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Bo Yu
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Shengjian Lu
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Lujie Zhang
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of TechnologyBeijingChina
| | - Senmiao Zhu
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Zhonghao Yu
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Tian Xia
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of MedicinePalo AltoUnited States
| | - WenHao Jiang
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Si Zhang
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Lanfang Sun
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Qian Ye
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Jiaying Sun
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Hui Zhu
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Pingping Huang
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Huifeng Hong
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Shuaishuai Yu
- School of Laboratory Medicine and Life Sciences, Wenzhou Medical UniversityWenzhouChina
| | - Wenjie Li
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of TechnologyBeijingChina
| | - Danni Ai
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of TechnologyBeijingChina
| | - Jingfan Fan
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of TechnologyBeijingChina
| | - Wentao Li
- School of Computer Science & Technology, Beijing Institute of TechnologyBeijingChina
| | - Hong Song
- School of Computer Science & Technology, Beijing Institute of TechnologyBeijingChina
| | - Lei Xu
- Medical Radiology Department, 2nd Affiliated Hospital, Wenzhou Medical UniversityWenzhouChina
| | - Xiwen Chen
- Animal Facility Center, Wenzhou Medical UniversityWenzhouChina
| | - Tongke Chen
- Animal Facility Center, Wenzhou Medical UniversityWenzhouChina
| | - Meng Zhou
- School of Biomedical Engineering, The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Jingxing Ou
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated, Hospital, Guangdong Province Engineering Laboratory for Transplantation MedicineGuangzhouChina,Guangdong Key Laboratory of Liver Disease Research, the Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouChina
| | - Jian Yang
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of TechnologyBeijingChina
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, National Institute of Health, NIHBethesdaUnited States
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of MedicinePalo AltoUnited States
| | - Wencan Wu
- The Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical UniversityWenzhouChina
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22
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Hetzer SM, Shalosky EM, Torrens JN, Evanson NK. Chronic Histological Outcomes of Indirect Traumatic Optic Neuropathy in Adolescent Mice: Persistent Degeneration and Temporally Regulated Glial Responses. Cells 2021; 10:3343. [PMID: 34943851 PMCID: PMC8699438 DOI: 10.3390/cells10123343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 11/17/2022] Open
Abstract
Injury to the optic nerve, termed, traumatic optic neuropathy (TON) is a known comorbidity of traumatic brain injury (TBI) and is now known to cause chronic and progressive retinal thinning up to 35 years after injury. Although animal models of TBI have described the presence of optic nerve degeneration and research exploring acute mechanisms is underway, few studies in humans or animals have examined chronic TON pathophysiology outside the retina. We used a closed-head weight-drop model of TBI/TON in 6-week-old male C57BL/6 mice. Mice were euthanized 7-, 14-, 30-, 90-, and 150-days post-injury (DPI) to assess histological changes in the visual system of the brain spanning a total of 12 regions. We show chronic elevation of FluoroJade-C, indicative of neurodegeneration, throughout the time course. Intriguingly, FJ-C staining revealed a bimodal distribution of mice indicating the possibility of subpopulations that may be more or less susceptible to injury outcomes. Additionally, we show that microglia and astrocytes react to optic nerve damage in both temporally and regionally different ways. Despite these differences, astrogliosis and microglial changes were alleviated between 14-30 DPI in all regions examined, perhaps indicating a potentially critical period for intervention/recovery that may determine chronic outcomes.
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Affiliation(s)
- Shelby M. Hetzer
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
| | - Emily M. Shalosky
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA;
| | - Jordyn N. Torrens
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
| | - Nathan K. Evanson
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45229, USA
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23
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Honig MG, Del Mar NA, Henderson DL, O'Neal D, Doty JB, Cox R, Li C, Perry AM, Moore BM, Reiner A. Raloxifene Modulates Microglia and Rescues Visual Deficits and Pathology After Impact Traumatic Brain Injury. Front Neurosci 2021; 15:701317. [PMID: 34776838 PMCID: PMC8585747 DOI: 10.3389/fnins.2021.701317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/07/2021] [Indexed: 11/29/2022] Open
Abstract
Mild traumatic brain injury (TBI) involves widespread axonal injury and activation of microglia, which initiates secondary processes that worsen the TBI outcome. The upregulation of cannabinoid type-2 receptors (CB2) when microglia become activated allows CB2-binding drugs to selectively target microglia. CB2 inverse agonists modulate activated microglia by shifting them away from the harmful pro-inflammatory M1 state toward the helpful reparative M2 state and thus can stem secondary injury cascades. We previously found that treatment with the CB2 inverse agonist SMM-189 after mild TBI in mice produced by focal cranial blast rescues visual deficits and the optic nerve axon loss that would otherwise result. We have further shown that raloxifene, which is Food and Drug Administration (FDA)-approved as an estrogen receptor modulator to treat osteoporosis, but also possesses CB2 inverse agonism, yields similar benefit in this TBI model through its modulation of microglia. As many different traumatic events produce TBI in humans, it is widely acknowledged that diverse animal models must be used in evaluating possible therapies. Here we examine the consequences of TBI created by blunt impact to the mouse head for visual function and associated pathologies and assess raloxifene benefit. We found that mice subjected to impact TBI exhibited decreases in contrast sensitivity and the B-wave of the electroretinogram, increases in light aversion and resting pupil diameter, and optic nerve axon loss, which were rescued by daily injection of raloxifene at 5 or 10 mg/ml for 2 weeks. Raloxifene treatment was associated with reduced M1 activation and/or enhanced M2 activation in retina, optic nerve, and optic tract after impact TBI. Our results suggest that the higher raloxifene dose, in particular, may be therapeutic for the optic nerve by enhancing the phagocytosis of axonal debris that would otherwise promote inflammation, thereby salvaging less damaged axons. Our current work, together with our prior studies, shows that microglial activation drives secondary injury processes after both impact and cranial blast TBI and raloxifene mitigates microglial activation and visual system injury in both cases. The results thus provide a strong basis for phase 2 human clinical trials evaluating raloxifene as a TBI therapy.
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Affiliation(s)
- Marcia G Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Desmond L Henderson
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Dylan O'Neal
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - John B Doty
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Rachel Cox
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Chunyan Li
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Aaron M Perry
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Bob M Moore
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, United States.,Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, United States
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24
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Desai A, Chen H, Kevala K, Kim HY. Higher n-3 Polyunsaturated Fatty Acid Diet Improves Long-Term Neuropathological and Functional Outcome after Repeated Mild Traumatic Brain Injury. J Neurotrauma 2021; 38:2622-2632. [PMID: 33913741 PMCID: PMC8403198 DOI: 10.1089/neu.2021.0096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Repeated mild traumatic brain injury (TBI) can cause persistent neuropathological effects and is a major risk factor for chronic traumatic encephalopathy. PUFAs (n-3 polyunsaturated fatty acids) were shown to improve acute TBI outcomes in single-injury models in most cases. In this study, we demonstrate positive effects of dietary n-3 PUFA on long-term neuropathological and functional outcome in a clinically relevant model of repeated mild TBI using the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA). Adult mice, reared on n-3 PUFA adequate (higher n-3 PUFA) or deficient (lower n-3 PUFA) diets, were given a mild CHIMERA daily for 3 consecutive days. At 2 months after injury, visual function and spatial memory were evaluated. Glia cell activation was assessed by immunostaining using antibodies of ionized calcium-binding adaptor molecule 1 and glial fibrillary acidic protein, and axonal damage was examined using silver staining. Repeated CHIMERA (rCHIMERA)-induced gliosis was significantly suppressed in the optic tract, corpus callosum, and hippocampus of mice fed the n-3 PUFA adequate diet compared to the deficient diet group. Considerable axonal damage was detected in the optic tract after rCHIMERA, but the adequate diet group displayed less axonal damage compared to the deficient diet group. rCHIMERA induced a drastic reduction in N1 amplitude of the visual evoked potential in both diet groups and the a-wave amplitude of the electroretinogram in the deficient diet group. However, reduction of N1 and a-wave amplitude were less severe in the adequate diet group. The Morris water maze probe test indicated a significant decrease in the number of platform crossings in the deficient diet group compared to the adequate group. In summary, dietary n-3 PUFA can attenuate persistent glial cell activation and axonal damage and improve deficits in visual function and spatial memory after repeated mild TBI. These data support the neuroprotective potential of a higher n-3 PUFA diet in ameliorating the adverse outcome of repeated mild TBI.
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Affiliation(s)
- Abhishek Desai
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Huazhen Chen
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, Bethesda, Maryland, USA
| | - Karl Kevala
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Hee-Yong Kim
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, Bethesda, Maryland, USA
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25
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Faillot M, Chaillet A, Palfi S, Senova S. Rodent models used in preclinical studies of deep brain stimulation to rescue memory deficits. Neurosci Biobehav Rev 2021; 130:410-432. [PMID: 34437937 DOI: 10.1016/j.neubiorev.2021.08.012] [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: 02/08/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 11/28/2022]
Abstract
Deep brain stimulation paradigms might be used to treat memory disorders in patients with stroke or traumatic brain injury. However, proof of concept studies in animal models are needed before clinical translation. We propose here a comprehensive review of rodent models for Traumatic Brain Injury and Stroke. We systematically review the histological, behavioral and electrophysiological features of each model and identify those that are the most relevant for translational research.
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Affiliation(s)
- Matthieu Faillot
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Antoine Chaillet
- Laboratoire des Signaux et Systèmes (L2S-UMR8506) - CentraleSupélec, Université Paris Saclay, Institut Universitaire de France, France
| | - Stéphane Palfi
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Suhan Senova
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France.
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26
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Chen H, Kevala K, Aflaki E, Marugan J, Kim HY. GPR110 ligands reduce chronic optic tract gliosis and visual deficit following repetitive mild traumatic brain injury in mice. J Neuroinflammation 2021; 18:157. [PMID: 34273979 PMCID: PMC8286622 DOI: 10.1186/s12974-021-02195-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/16/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Repetitive mild traumatic brain injury (mTBI) can result in chronic visual dysfunction. G-protein receptor 110 (GPR110, ADGRF1) is the target receptor of N-docosahexaenoylethanolamine (synaptamide) mediating the anti-neuroinflammatory function of synaptamide. In this study, we evaluated the effect of an endogenous and a synthetic ligand of GPR110, synaptamide and (4Z,7Z,10Z,13Z,16Z,19Z)-N-(2-hydroxy-2-methylpropyl) docosa-4,7,10,13,16,19-hexaenamide (dimethylsynaptamide, A8), on the mTBI-induced long-term optic tract histopathology and visual dysfunction using Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA), a clinically relevant model of mTBI. METHODS The brain injury in wild-type (WT) and GPR110 knockout (KO) mice was induced by CHIMERA applied daily for 3 days, and GPR110 ligands were intraperitoneally injected immediately following each impact. The expression of GPR110 and proinflammatory mediator tumor necrosis factor (TNF) in the brain was measured by using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) in an acute phase. Chronic inflammatory responses in the optic tract and visual dysfunction were assessed by immunostaining for Iba-1 and GFAP and visual evoked potential (VEP), respectively. The effect of GPR110 ligands in vitro was evaluated by the cyclic adenosine monophosphate (cAMP) production in primary microglia isolated from adult WT or KO mouse brains. RESULTS CHIMERA injury acutely upregulated the GPR110 and TNF gene level in mouse brain. Repetitive CHIMERA (rCHIMERA) increased the GFAP and Iba-1 immunostaining of glia cells and silver staining of degenerating axons in the optic tract with significant reduction of N1 amplitude of visual evoked potential at up to 3.5 months after injury. Both GPR110 ligands dose- and GPR110-dependently increased cAMP in cultured primary microglia with A8, a ligand with improved stability, being more effective than synaptamide. Intraperitoneal injection of A8 at 1 mg/kg or synaptamide at 5 mg/kg significantly reduced the acute expression of TNF mRNA in the brain and ameliorated chronic optic tract microgliosis, astrogliosis, and axonal degeneration as well as visual deficit caused by injury in WT but not in GPR110 KO mice. CONCLUSION Our data demonstrate that ligand-induced activation of the GPR110/cAMP system upregulated after injury ameliorates the long-term optic tract histopathology and visual impairment caused by rCHIMERA. Based on the anti-inflammatory nature of GPR110 activation, we suggest that GPR110 ligands may have therapeutic potential for chronic visual dysfunction associated with mTBI.
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Key Words
- A8 (4Z,7Z,10Z,13Z,16Z,19Z)-N-(2-hydroxy-2-methylpropyl) docosa-4,7,10,13,16,19-hexaenamide (dimethylsynaptamide)
- GPR110
- Histopathology
- Optic tract
- Synaptamide
- VEP
- Visual deficit
- mTBI
- repetitive CHIMERA
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Affiliation(s)
- Huazhen Chen
- Laboratory of Molecular Signaling, NIAAA, NIH, 5625 Fishers Lane, Rockville, MD, 20852, USA.,Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, Bethesda, MD, 20817, USA
| | - Karl Kevala
- Laboratory of Molecular Signaling, NIAAA, NIH, 5625 Fishers Lane, Rockville, MD, 20852, USA
| | - Elma Aflaki
- Laboratory of Molecular Signaling, NIAAA, NIH, 5625 Fishers Lane, Rockville, MD, 20852, USA
| | - Juan Marugan
- Division of Pre-Clinical Innovation, NCATS, NIH, Rockville, MD, 20817, USA
| | - Hee-Yong Kim
- Laboratory of Molecular Signaling, NIAAA, NIH, 5625 Fishers Lane, Rockville, MD, 20852, USA. .,Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation, Bethesda, MD, 20817, USA.
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27
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Kahriman A, Bouley J, Smith TW, Bosco DA, Woerman AL, Henninger N. Mouse closed head traumatic brain injury replicates the histological tau pathology pattern of human disease: characterization of a novel model and systematic review of the literature. Acta Neuropathol Commun 2021; 9:118. [PMID: 34187585 PMCID: PMC8243463 DOI: 10.1186/s40478-021-01220-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/18/2021] [Indexed: 12/15/2022] Open
Abstract
Traumatic brain injury (TBI) constitutes one of the strongest environmental risk factors for several progressive neurodegenerative disorders of cognitive impairment and dementia that are characterized by the pathological accumulation of hyperphosphorylated tau (p-Tau). It has been questioned whether mouse closed-head TBI models can replicate human TBI-associated tauopathy. We conducted longitudinal histopathological characterization of a mouse closed head TBI model, with a focus on pathological features reported in human TBI-associated tauopathy. Male C57BL/6 J mice were subjected to once daily TBI for 5 consecutive days using a weight drop paradigm. Histological analyses (AT8, TDP-43, pTDP-43, NeuN, GFAP, Iba-1, MBP, SMI-312, Prussian blue, IgG, βAPP, alpha-synuclein) were conducted at 1 week, 4 weeks, and 24 weeks after rTBI and compared to sham operated controls. We conducted a systematic review of the literature for mouse models of closed-head injury focusing on studies referencing tau protein assessment. At 1-week post rTBI, p-Tau accumulation was restricted to the corpus callosum and perivascular spaces adjacent to the superior longitudinal fissure. Progressive p-Tau accumulation was observed in the superficial layers of the cerebral cortex, as well as in mammillary bodies and cortical perivascular, subpial, and periventricular locations at 4 to 24 weeks after rTBI. Associated cortical histopathologies included microvascular injury, neuroaxonal rarefaction, astroglial and microglial activation, and cytoplasmatic localization of TDP-43 and pTDP-43. In our systematic review, less than 1% of mouse studies (25/3756) reported p-Tau using immunostaining, of which only 3 (0.08%) reported perivascular p-Tau, which is considered a defining feature of chronic traumatic encephalopathy. Commonly reported associated pathologies included neuronal loss (23%), axonal loss (43%), microglial activation and astrogliosis (50%, each), and beta amyloid deposition (29%). Our novel model, supported by systematic review of the literature, indicates progressive tau pathology after closed head murine TBI, highlighting the suitability of mouse models to replicate pertinent human histopathology.
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Affiliation(s)
- Aydan Kahriman
- Department of Neurology, Medical School, University of Massachusetts, 55 Lake Ave, Worcester, USA
| | - James Bouley
- Department of Neurology, Medical School, University of Massachusetts, 55 Lake Ave, Worcester, USA
| | - Thomas W Smith
- Department of Pathology, Medical School, University of Massachusetts, 55 Lake Ave, Worcester, USA
| | - Daryl A Bosco
- Department of Neurology, Medical School, University of Massachusetts, 55 Lake Ave, Worcester, USA
| | - Amanda L Woerman
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Nils Henninger
- Department of Neurology, Medical School, University of Massachusetts, 55 Lake Ave, Worcester, USA.
- Department of Psychiatry, Medical School, University of Massachusetts, 55 Lake Ave, Worcester, USA.
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28
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Tucker LB, Fu AH, McCabe JT. Hippocampal-Dependent Cognitive Dysfunction following Repeated Diffuse Rotational Brain Injury in Male and Female Mice. J Neurotrauma 2021; 38:1585-1606. [PMID: 33622092 PMCID: PMC8126427 DOI: 10.1089/neu.2021.0025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cognitive dysfunction is a common, often long-term complaint following acquired traumatic brain injury (TBI). Cognitive deficits suggest dysfunction in hippocampal circuits. The goal of the studies described here is to phenotype in both male and female mice the hippocampal-dependent learning and memory deficits resulting from TBI sustained by the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA) device—a model that delivers both a contact–concussion injury as well as unrestrained rotational head movement. Mice sustained either sham procedures or four injuries (0.7 J, 24-h intervals). Spatial learning and memory skills assessed in the Morris water maze (MWM) approximately 3 weeks following injuries were significantly impaired by brain injuries; however, slower swimming speeds and poor performance on visible platform trials suggest that measurement of cognitive impairment with this test is confounded by injury-induced motor and/or visual impairments. A separate experiment confirmed hippocampal-dependent cognitive deficits with trace fear conditioning (TFC), a behavioral test less dependent on motor and visual function. Male mice had greater injury-induced deficits on both the MWM and TFC tests than female mice. Pathologically, the injury was characterized by white matter damage as observed by silver staining and glial fibrillary acidic protein (astrogliosis) in the optic tracts, with milder damage seen in the corpus callosum, and fimbria and brainstem (cerebral peduncles) of some animals. No changes in the density of GABAergic parvalbumin-expressing cells in the hippocampus, amygdala, or parietal cortex were found. This experiment confirmed significant sexually dimorphic cognitive impairments following a repeated, diffuse brain injury.
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Affiliation(s)
- Laura B Tucker
- Center for Neuroscience and Regenerative Medicine, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amanda H Fu
- Center for Neuroscience and Regenerative Medicine, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Joseph T McCabe
- Center for Neuroscience and Regenerative Medicine, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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29
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Hetzer SM, Guilhaume-Correa F, Day D, Bedolla A, Evanson NK. Traumatic Optic Neuropathy Is Associated with Visual Impairment, Neurodegeneration, and Endoplasmic Reticulum Stress in Adolescent Mice. Cells 2021; 10:cells10050996. [PMID: 33922788 PMCID: PMC8146890 DOI: 10.3390/cells10050996] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/02/2021] [Accepted: 04/17/2021] [Indexed: 02/02/2023] Open
Abstract
Traumatic brain injury (TBI) results in a number of impairments, often including visual symptoms. In some cases, visual impairments after head trauma are mediated by traumatic injury to the optic nerve, termed traumatic optic neuropathy (TON), which has few effective options for treatment. Using a murine closed-head weight-drop model of head trauma, we previously reported in adult mice that there is relatively selective injury to the optic tract and thalamic/brainstem projections of the visual system. In the current study, we performed blunt head trauma on adolescent C57BL/6 mice and investigated visual impairment in the primary visual system, now including the retina and using behavioral and histologic methods at new time points. After injury, mice displayed evidence of decreased optomotor responses illustrated by decreased optokinetic nystagmus. There did not appear to be a significant change in circadian locomotor behavior patterns, although there was an overall decrease in locomotor behavior in mice with head injury. There was evidence of axonal degeneration of optic nerve fibers with associated retinal ganglion cell death. There was also evidence of astrogliosis and microgliosis in major central targets of optic nerve projections. Further, there was elevated expression of endoplasmic reticulum (ER) stress markers in retinas of injured mice. Visual impairment, histologic markers of gliosis and neurodegeneration, and elevated ER stress marker expression persisted for at least 30 days after injury. The current results extend our previous findings in adult mice into adolescent mice, provide direct evidence of retinal ganglion cell injury after head trauma and suggest that axonal degeneration is associated with elevated ER stress in this model of TON.
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Affiliation(s)
- Shelby M. Hetzer
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; (S.M.H.); (D.D.); (A.B.)
| | - Fernanda Guilhaume-Correa
- Translational Biology, Medicine and Health, Virginia Polytechnic Institute and State University, Roanoke, VA 24016, USA;
| | - Dylan Day
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; (S.M.H.); (D.D.); (A.B.)
| | - Alicia Bedolla
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; (S.M.H.); (D.D.); (A.B.)
| | - Nathan K. Evanson
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; (S.M.H.); (D.D.); (A.B.)
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45229, USA
- Correspondence:
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30
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Karimi S, Arabi A, Ansari I, Shahraki T, Safi S. A Systematic Literature Review on Traumatic Optic Neuropathy. J Ophthalmol 2021; 2021:5553885. [PMID: 33728056 PMCID: PMC7935564 DOI: 10.1155/2021/5553885] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/14/2021] [Accepted: 02/18/2021] [Indexed: 01/01/2023] Open
Abstract
Traumatic optic neuropathy (TON) is an uncommon vision-threatening disorder that can be caused by ocular or head trauma and is categorized into direct and indirect TON. The overall incidence of TON is 0.7-2.5%, and indirect TON has a higher prevalence than direct TON. Detection of an afferent pupillary defect in the presence of an intact globe in a patient with ocular or head trauma with decreased visual acuity strongly suggests TON. However, afferent pupillary defects may be difficult to detect in patients who have received narcotics that cause pupillary constriction and in those with bilateral TON. Mechanical shearing of the optic nerve axons and contusion necrosis due to immediate ischemia from damage to the optic nerve microcirculation and apoptosis of neurons is a probable mechanism. The proper management of TON is controversial. High-dose corticosteroid therapy and decompression of the optic nerve provide no additional benefit over observation alone. Intravenous erythropoietin may be a safe and efficient treatment for patients with TON.
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Affiliation(s)
- Saeed Karimi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Ophthalmology, Torfeh Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Arabi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Ophthalmology, Torfeh Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Iman Ansari
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Ophthalmology, Torfeh Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Toktam Shahraki
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Ophthalmology, Torfeh Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sare Safi
- Ophthalmic Epidemiology Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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31
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Verboon LN, Patel HC, Greenhalgh AD. The Immune System's Role in the Consequences of Mild Traumatic Brain Injury (Concussion). Front Immunol 2021; 12:620698. [PMID: 33679762 PMCID: PMC7928307 DOI: 10.3389/fimmu.2021.620698] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Mild traumatic brain injury (mild TBI), often referred to as concussion, is the most common form of TBI and affects millions of people each year. A history of mild TBI increases the risk of developing emotional and neurocognitive disorders later in life that can impact on day to day living. These include anxiety and depression, as well as neurodegenerative conditions such as chronic traumatic encephalopathy (CTE) and Alzheimer's disease (AD). Actions of brain resident or peripherally recruited immune cells are proposed to be key regulators across these diseases and mood disorders. Here, we will assess the impact of mild TBI on brain and patient health, and evaluate the recent evidence for immune cell involvement in its pathogenesis.
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Affiliation(s)
- Laura N. Verboon
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, United Kingdom
| | - Hiren C. Patel
- Division of Cardiovascular Sciences, Salford Royal National Health Service Foundation Trust, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Geoffrey Jefferson Brain Research Centre, The Manchester Academic Health Science Centre, Northern Care Alliance National Health Service Group, University of Manchester, Manchester, United Kingdom
| | - Andrew D. Greenhalgh
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, United Kingdom
- Geoffrey Jefferson Brain Research Centre, The Manchester Academic Health Science Centre, Northern Care Alliance National Health Service Group, University of Manchester, Manchester, United Kingdom
- Lydia Becker Institute of Immunology and Inflammation, The University of Manchester, Manchester, United Kingdom
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32
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Borucki DM, Toutonji A, Couch C, Mallah K, Rohrer B, Tomlinson S. Complement-Mediated Microglial Phagocytosis and Pathological Changes in the Development and Degeneration of the Visual System. Front Immunol 2020; 11:566892. [PMID: 33072106 PMCID: PMC7541817 DOI: 10.3389/fimmu.2020.566892] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/17/2020] [Indexed: 12/21/2022] Open
Abstract
The focus of this review is the role of complement-mediated phagocytosis in retinal and neurological diseases affecting the visual system. Complement activation products opsonize synaptic material on neurons for phagocytic removal, which is a normal physiological process during development, but a pathological process in several neurodegenerative diseases and conditions. We discuss the role of complement in the refinement and elimination of synapses in the retina and lateral geniculate nucleus, both during development and in disease states. How complement and aberrant phagocytosis promotes injury to the visual system is discussed primarily in the context of multiple sclerosis, where it has been extensively studied, although the role of complement in visual dysfunction in other diseases such as stroke and traumatic brain injury is also highlighted. Retinal diseases are also covered, with a focus on glaucoma and age-related macular degeneration. Finally, we discuss the potential of complement inhibitory strategies to treat diseases affecting the visual system.
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Affiliation(s)
- Davis M. Borucki
- Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Amer Toutonji
- Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Christine Couch
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Khalil Mallah
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| | - Baerbel Rohrer
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, United States
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States
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33
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Keating CE, Browne KD, Duda JE, Cullen DK. Neurons in Subcortical Oculomotor Regions Are Vulnerable to Plasma Membrane Damage after Repetitive Diffuse Traumatic Brain Injury in Swine. J Neurotrauma 2020; 37:1918-1932. [PMID: 32178582 DOI: 10.1089/neu.2019.6738] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oculomotor deficits, such as insufficiencies in accommodation, convergence, and saccades, are common following traumatic brain injury (TBI). Previous studies in patients with mild TBI attributed these deficits to insufficient activation of subcortical oculomotor nuclei, although the exact mechanism is unknown. A possible cause for neuronal dysfunction in these regions is biomechanically induced plasma membrane permeability. We used our established porcine model of head rotational TBI to investigate whether cell permeability changes occurred in subcortical oculomotor areas following single or repetitive TBI, with repetitive injuries separated by 15 min, 3 days, or 7 days. Swine were subjected to sham conditions or head rotational acceleration in the sagittal plane using a HYGE pneumatic actuator. Two hours prior to the final injury, the cell-impermeant dye Lucifer Yellow was injected into the ventricles to diffuse throughout the interstitial space to assess plasmalemmal permeability. Animals were sacrificed 15 min after the final injury for immunohistological analysis. Brain regions examined for cell membrane permeability included caudate, substantia nigra pars reticulata, superior colliculus, and cranial nerve oculomotor nuclei. We found that the distribution of permeabilized neurons varied depending on the number and spacing of injuries. Repetitive injuries separated by 15 min or 3 days resulted in the most permeability. Many permeabilized cells lost neuron-specific nuclear protein reactivity, although no neuronal loss occurred acutely after injury. Microglia contacted and appeared to begin phagocytosing permeabilized neurons in repetitively injured animals. These pathologies within oculomotor areas may mediate transient dysfunction and/or degeneration that may contribute to oculomotor deficits following diffuse TBI.
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Affiliation(s)
- Carolyn E Keating
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin D Browne
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John E Duda
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - D Kacy Cullen
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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34
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Gazdzinski LM, Mellerup M, Wang T, Adel SAA, Lerch JP, Sled JG, Nieman BJ, Wheeler AL. White Matter Changes Caused by Mild Traumatic Brain Injury in Mice Evaluated Using Neurite Orientation Dispersion and Density Imaging. J Neurotrauma 2020; 37:1818-1828. [PMID: 32242488 DOI: 10.1089/neu.2020.6992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mild traumatic brain injury (mTBI) is common and can lead to persistent cognitive and behavioral symptoms. Although diffusion tensor imaging (DTI) has demonstrated some sensitivity to changes in white matter following mTBI, recent studies have suggested that more complex geometric models of diffusion, including the neurite orientation dispersion and density imaging (NODDI) model, may be more sensitive and specific. Here, we evaluate microstructural changes in white matter following mTBI using DTI and NODDI in a mouse model, and compare the time course of these changes to behavioral impairment and recovery. We also assess volumetric changes for a comprehensive picture of the structural alterations in the brain and histological staining to identify cellular changes that may contribute to the differences detected in the imaging data. Increased orientation dispersion index (ODI) was observed in the optic tracts of mTBI mice compared with shams. Changes in fractional anisotropy (FA) were not statistically significant. Volume deficits were detected in the optic tract as well as in several gray matter regions: the lateral geniculate nuclei of the thalamus, the entorhinal cortex, and the superior colliculi. Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba1) staining was increased in the optic tracts of mTBI brains, and this staining correlated with ODI values. A transient impairment in working memory was observed, which resolved by 6 weeks, whereas increased ODI, GFAP, and Iba1 persisted to 18 weeks post-injury. We conclude that the optic tracts are particularly vulnerable to damage from the closed-skull impact model used in this study, and that ODI may be a more sensitive metric to this damage than FA. Differences in ODI and in histological measures of astrogliosis, neuroinflammation, and axonal degeneration persist beyond behavioral impairment in this model.
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Affiliation(s)
- Lisa M Gazdzinski
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Miranda Mellerup
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology and University of Toronto, Toronto, Ontario, Canada
| | - Tong Wang
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology and University of Toronto, Toronto, Ontario, Canada
| | - Seyed Amir Ali Adel
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology and University of Toronto, Toronto, Ontario, Canada
| | - Jason P Lerch
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Wellcome Centre for Integrative Neuroimaging, Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - John G Sled
- Translational Medicine, Hospital for Sick Children, Toronto, Ontario, Canada.,Mouse Imaging Centre at The Centre for Phenogenomics, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Brian J Nieman
- Translational Medicine, Hospital for Sick Children, Toronto, Ontario, Canada.,Mouse Imaging Centre at The Centre for Phenogenomics, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Anne L Wheeler
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology and University of Toronto, Toronto, Ontario, Canada
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35
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Anderson J, Patel M, Forenzo D, Ai X, Cai C, Wade Q, Risman R, Cai L. A novel mouse model for the study of endogenous neural stem and progenitor cells after traumatic brain injury. Exp Neurol 2020; 325:113119. [PMID: 31751572 PMCID: PMC10885014 DOI: 10.1016/j.expneurol.2019.113119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/23/2019] [Accepted: 11/16/2019] [Indexed: 11/29/2022]
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability in the US. Neural stem/progenitor cells (NSPCs) persist in the adult brain and represent a potential cell source for tissue regeneration and wound healing after injury. The Notch signaling pathway is critical for embryonic development and adult brain injury response. However, the specific role of Notch signaling in the injured brain is not well characterized. Our previous study has established a Notch1CR2-GFP reporter mouse line in which the Notch1CR2 enhancer directs GFP expression in NSPCs and their progeny. In this study, we performed closed head injury (CHI) in the Notch1CR2-GFP mice to study the response of injury-activated NSPCs. We show that CHI induces neuroinflammation, cell death, and the expression of typical TBI markers (e.g., ApoE, Il1b, and Tau), validating the animal model. In addition, CHI induces cell proliferation in GFP+ cells expressing NSPC markers, e.g., Notch1 and Nestin. A significant higher percentage of GFP+ astrocytes and GABAergic neurons was observed in the injured brain, with no significant change in oligodendrocyte lineage between the CHI and sham animal groups. Since injury is known to activate astrogliosis, our results suggest that injury-induced GFP+ NSPCs preferentially differentiate into GABAergic neurons. Our study establishes that Notch1CR2-GFP transgenic mouse is a useful tool for the study of NSPC behavior in vivo after TBI. Unveiling the potential of NSPCs response to TBI (e.g., proliferation and differentiation) will identify new therapeutic strategy for the treatment of brain trauma.
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Affiliation(s)
- Jeremy Anderson
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Misaal Patel
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Dylan Forenzo
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Xin Ai
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Catherine Cai
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Quinn Wade
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Rebecca Risman
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
| | - Li Cai
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America.
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Cheng H, Deaton LM, Qiu M, Ha S, Pacoma R, Lao J, Tolley V, Moran R, Keeton A, Lamb JR, Fathman J, Walker JR, Schumacher AM. Tau overexpression exacerbates neuropathology after repeated mild head impacts in male mice. Neurobiol Dis 2019; 134:104683. [PMID: 31765727 DOI: 10.1016/j.nbd.2019.104683] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/22/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023] Open
Abstract
Repeated mild traumatic brain injury (rmTBI) can lead to development of chronic traumatic encephalopathy (CTE), which is characterized by progressive neurodegeneration with presence of white matter damage, gliosis and hyper-phosphorylated tau. While animal models of rmTBI have been documented, few characterize the molecular pathogenesis and expression profiles of relevant injured brain regions. Additionally, while the usage of transgenic tau mice in rmTBI is prevalent, the effects of tau on pathological outcomes has not been well studied. Here we characterized a 42-impact closed-head rmTBI paradigm on 3-4 month old male C57BL/6 (WT) and Tau-overexpressing mice (Tau58.4). This injury paradigm resulted in chronic gliosis, T-cell infiltration, and demyelination of the optic nerve and associated white matter tracts at 1-month post-injury. At 3-months post-injury, Tau58.4 mice showed progressive neuroinflammation and neurodegeneration in multiple brain regions compared to WT mice. Corresponding to histopathology, RNAseq of the optic nerve tract at 1-month post-injury showed significant upregulation of inflammatory pathways and downregulation of myelin synthetic pathways in both genotypes. However, Tau58.4 mice showed additional changes in neurite development, protein processing, and cell stress. Comparisons with published transcriptomes of human Alzheimer's Disease and CTE revealed common signatures including neuroinflammation and downregulation of protein phosphatases. We next investigated the demyelination and T-cell infiltration phenotypes to determine whether these offer potential avenues for therapeutic intervention. Tau58.4 mice were treated with the histamine H3 receptor antagonist GSK239512 for 1-month post-injury to promote remyelination of white matter lesions. This restored myelin gene expression to sham levels but failed to repair the histopathologic lesions. Likewise, injured T-cell-deficient Rag2/Il2rg (R2G2) mice also showed evidence for inflammation and loss of myelin. However, unlike immune-competent mice, R2G2 mice had altered myeloid cell gene expression and fewer demyelinated lesions. Together this data shows that rmTBI leads to chronic white matter inflammatory demyelination and axonal loss exacerbated by human tau overexpression but suggests that immune-suppression and remyelination alone are insufficient to reverse damage.
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Affiliation(s)
- Hank Cheng
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Lisa M Deaton
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Minhua Qiu
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Sukwon Ha
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Reynand Pacoma
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Jianmin Lao
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Valerie Tolley
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Rita Moran
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Amber Keeton
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - John R Lamb
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA
| | - John Fathman
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - John R Walker
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
| | - Andrew M Schumacher
- Department of General Medical Biology, Genomics Institute for the Novartis Research Foundation, San Diego, CA 92121, USA.
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37
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Desai A, Chen H, Kim HY. Multiple Mild Traumatic Brain Injuries Lead to Visual Dysfunction in a Mouse Model. J Neurotrauma 2019; 37:286-294. [PMID: 31530220 DOI: 10.1089/neu.2019.6602] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Visual dysfunction is a common occurrence after traumatic brain injury (TBI). We investigated in this study effects of single or multiple mild TBI on visual function in mice using a closed head injury model that permits unconstrained head movement after impact. Adult mice were briefly anesthetized with isoflurane and given one or three mild TBI with the closed head injury by mechanically engineered rotational acceleration (CHIMERA) device with an interinjury interval of 24 h. Mice were then tested in the Morris water maze, visual cliff, and open field tests from day 19 to day 32 and for visual evoked potential at 5 weeks after the last injury and euthanized. Mice with multiple TBI showed impaired performance in the visible platform water maze test and had increased errors in the visual cliff test. Further, there was a graded difference in visual evoked potential, with the single injury mice showing modest reduction in N1 amplitude whereas the multiple injuries produced significant reduction compared to sham and single injury groups. The optic tract of the injured mice showed increases in glial cell immunostaining. The increase in glial fibrillary acid protein immunostaining reached statistical significance for both injured groups whereas the ionized calcium binding adaptor molecule 1 immunostaining was only significantly increased in the optic tract of repeatedly injured mice. These results indicate that multiple injuries using CHIMERA may result in visual deficits, which can affect certain behavioral performances. The change in vision may be a useful marker when monitoring repeated TBI outcome and screening for protective agents from TBI.
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Affiliation(s)
- Abhishek Desai
- Laboratory of Molecular Signaling, NIAAA, NIH, Rockville, Maryland
| | - Huazhen Chen
- Laboratory of Molecular Signaling, NIAAA, NIH, Rockville, Maryland.,Center for Neuroscience and Regenerative Medicine at the Uniformed Services University of Health Sciences, Bethesda, Maryland
| | - Hee-Yong Kim
- Laboratory of Molecular Signaling, NIAAA, NIH, Rockville, Maryland
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38
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Cansler SM, Evanson NK. Connecting endoplasmic reticulum and oxidative stress to retinal degeneration, TBI, and traumatic optic neuropathy. J Neurosci Res 2019; 98:571-574. [DOI: 10.1002/jnr.24543] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 10/07/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Shelby M. Cansler
- Division of Pediatric Rehabilitation Medicine Cincinnati Children’s Hospital Cincinnati OH USA
| | - Nathan K. Evanson
- Division of Pediatric Rehabilitation Medicine Cincinnati Children’s Hospital Cincinnati OH USA
- Department of Pediatrics University of Cincinnati Cincinnati OH USA
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39
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Guilhaume-Correa F, Cansler SM, Shalosky EM, Goodman MD, Evanson NK. Greater neurodegeneration and behavioral deficits after single closed head traumatic brain injury in adolescent versus adult male mice. J Neurosci Res 2019; 98:557-570. [PMID: 31541497 DOI: 10.1002/jnr.24535] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 12/28/2022]
Abstract
Traumatic brain injury (TBI) is a major public health concern affecting 2.8 million people per year in the United States, of whom about 1 million are children under 19 years old. Animal models of TBI have been developed and used in multiple ages of animals, but direct comparisons of adult and adolescent populations are rare. The current studies were undertaken to directly compare outcomes between adult and adolescent male mice, using a closed head, single-impact model of TBI. Six-week-old adolescent and 9-week-old adult male mice were subjected to mild-moderate TBI. Histological measures for neurodegeneration, gliosis, and microglial neuroinflammation, and behavioral tests of locomotion and memory were performed. Adolescent TBI mice have increased mortality (Χ2 = 20.72, p < 0.001) compared to adults. There is also evidence of hippocampal neurodegeneration in adolescents that is not present in adults. Hippocampal neurodegeneration correlates with histologic activation of microglia, but not with increased astrogliosis. Adults and adolescents have similar locomotion deficits after TBI that recover by 16 days postinjury. Adolescents have memory deficits as evidenced by impaired novel object recognition between 3-4 and 4-16 days postinjury (F1,26 = 5.23, p = 0.031) while adults do not. In conclusion, adults and adolescents within a close age range (6-9 weeks) respond to TBI differently. Adolescents are more severely affected by mortality, neurodegeneration, and inflammation in the hippocampus compared to adults. Adolescents, but not adults, have worse memory performance after TBI that lasts at least 16 days postinjury.
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Affiliation(s)
- Fernanda Guilhaume-Correa
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Shelby M Cansler
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Emily M Shalosky
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
| | | | - Nathan K Evanson
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
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40
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Bodnar CN, Roberts KN, Higgins EK, Bachstetter AD. A Systematic Review of Closed Head Injury Models of Mild Traumatic Brain Injury in Mice and Rats. J Neurotrauma 2019; 36:1683-1706. [PMID: 30661454 PMCID: PMC6555186 DOI: 10.1089/neu.2018.6127] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mild TBI (mTBI) is a significant health concern. Animal models of mTBI are essential for understanding mechanisms, and pathological outcomes, as well as to test therapeutic interventions. A variety of closed head models of mTBI that incorporate different aspects (i.e., biomechanics) of the mTBI have been reported. The aim of the current review was to compile a comprehensive list of the closed head mTBI rodent models, along with the common data elements, and outcomes, with the goal to summarize the current state of the field. Publications were identified from a search of PubMed and Web of Science and screened for eligibility following PRISMA guidelines. Articles were included that were closed head injuries in which the authors classified the injury as mild in rats or mice. Injury model and animal-specific common data elements, as well as behavioral and histological outcomes, were collected and compiled from a total of 402 articles. Our results outline the wide variety of methods used to model mTBI. We also discovered that female rodents and both young and aged animals are under-represented in experimental mTBI studies. Our findings will aid in providing context comparing the injury models and provide a starting point for the selection of the most appropriate model of mTBI to address a specific hypothesis. We believe this review will be a useful starting place for determining what has been done and what knowledge is missing in the field to reduce the burden of mTBI.
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Affiliation(s)
- Colleen N. Bodnar
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Kelly N. Roberts
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Emma K. Higgins
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Adam D. Bachstetter
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
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41
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Guley NM, Del Mar NA, Ragsdale T, Li C, Perry AM, Moore BM, Honig MG, Reiner A. Amelioration of visual deficits and visual system pathology after mild TBI with the cannabinoid type-2 receptor inverse agonist SMM-189. Exp Eye Res 2019; 182:109-124. [PMID: 30922891 DOI: 10.1016/j.exer.2019.03.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/11/2019] [Accepted: 03/19/2019] [Indexed: 12/20/2022]
Abstract
Mild TBI is often accompanied by visual system dysfunction and injury, which is at least partly caused by microglial neuroinflammatory processes initiated by the injury. Using our focal cranial blast mouse model of closed-skull mild TBI, we evaluated the ability of the cannabinoid type-2 (CB2) receptor inverse agonist SMM-189, which biases microglia from the harmful M1 state to the beneficial M2 state, to mitigate visual system dysfunction and injury after TBI. Male C57BL/6 or Thy1-EYFP reporter mice received a closed-head blast of either 0-psi (sham) or 50-psi to the left side of the cranium. Blast mice received vehicle or 6 mg/kg SMM-189 daily beginning 2 h after blast. Sham mice received vehicle. In some mice, retina and optic nerve/tract were assessed morphologically at 3-7 days after blast, while other mice were assessed functionally by Optomotry 30 days after blast and morphologically at ≥30 days after blast. Mice sacrificed at 3-7 days were treated daily until sacrificed, while those assessed ≥30 days after blast were treated daily for 2 weeks post blast. Axon damage was evident in the left optic nerve and its continuation as the right optic tract at 3 days post blast in vehicle-treated blast mice in the form of swollen axon bulbs, and was accompanied by a significant increase in the abundance of microglia. Testing at 30 days post blast revealed that the contrast sensitivity function was significantly reduced in both eyes in vehicle-treated blast mice compared to vehicle-treated sham blast mice, and axon counts at ≥30 days after blast revealed a ∼10% loss in left optic nerve in vehicle-treated blast mice. Left optic nerve axon loss was highly correlated with the left eye deficit in contrast sensitivity. Immunolabeling at 30 days post blast showed a significant increase in the abundance of microglia in the retinas of both eyes and in GFAP + Müller cell processes traversing the inner plexiform layer in the left eye of vehicle-treated blast mice. SMM-189 treatment reduced axon injury and microglial abundance at 3 days, and mitigated axon loss, contrast sensitivity deficits, microglial abundance, and Müller cell GFAP upregulation at ≥30 days after blast injury. Analysis of right optic tract microglia at 3 days post blast for M1 versus M2 markers revealed that SMM-189 biased microglia toward the M2 state, with this action of SMM-189 being linked to reduced axonal injury. Taken together, our results show that focal left side cranial blast resulted in impaired contrast sensitivity and retinal pathology bilaterally and optic nerve loss ipsilaterally. The novel cannabinoid drug SMM-189 significantly mitigated the functional deficit and the associated pathologies. Our findings suggest the value of combatting visual system injury after TBI by using CB2 inverse agonists such as SMM-189, which appear to target microglia and bias them away from the pro-inflammatory M1 state, toward the protective M2 state.
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Affiliation(s)
- Natalie M Guley
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Tyler Ragsdale
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Chunyan Li
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Aaron M Perry
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Bob M Moore
- Dept. of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Marcia G Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States; Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
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42
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Burke EG, Cansler SM, Evanson NK. Indirect traumatic optic neuropathy: modeling optic nerve injury in the context of closed head trauma. Neural Regen Res 2019; 14:593-594. [PMID: 30632497 PMCID: PMC6352606 DOI: 10.4103/1673-5374.247463] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Emma G Burke
- Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Shelby M Cansler
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital, Cincinnati, OH, USA
| | - Nathan K Evanson
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital; Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
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43
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Childs C, Barker LA, Gage AM, Loosemore M. Investigating possible retinal biomarkers of head trauma in Olympic boxers using optical coherence tomography. Eye Brain 2018; 10:101-110. [PMID: 30588143 PMCID: PMC6299469 DOI: 10.2147/eb.s183042] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Purpose Changes to retina have been reported after a number of neurodegenerative conditions. The purpose of this study was to investigate retinal structures in Olympic boxers exposed to frequent head blows. Methods Retinal imaging offers potential as a non-invasive biomarker of neuropathology. Macula and retinal nerve fiber layer (RNFL) thickness was measured using optical coherence tomography (OCT) in UK Olympic boxers attending two mandatory eye screening programs, 18 months apart. Data from the two eye screenings provide longitudinal data of retinal change over time. Sedentary healthy subjects (controls) without past or present history of concussion were also screened at the time of the second boxer screening to provide comparison of cross-sectional data. Results Sixteen Olympic boxers aged 20–33 years and 20 sedentary healthy controls, aged 24–45 years, were recruited. Significant macula thickening was observed over time (18 months) in 75% of right and 50% of left eye sectors. For RNFL, left eye quadrants thickened. For right eye RNFL quadrants, thickening and thinning of this layer were observed. Cross-sectional results showed thinner macula sectors and RNFL quadrants in Olympic boxers compared to controls. Conclusion Significant change to macula and RNFL densities, occurring over an 18 month interval is an unexpected finding in otherwise heathy elite sportsmen. In addition, macula and RNFL were thinner than healthy sedentary controls. OCT may prove clinically useful as a candidate retinal biomarker of neuropathological change after mild traumatic brain injury and/or repeat head blows.
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Affiliation(s)
- Charmaine Childs
- Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield, South Yorkshire, UK,
| | - Lynne A Barker
- Centre for Behavioural Science and Applied Psychology, Sheffield Hallam University, Sheffield, South Yorkshire, UK
| | - Alex Md Gage
- Alex Gage Family Optometrist, Sheffield, South Yorkshire, UK
| | - Mike Loosemore
- Institute of Sport, Exercise and Health (ISEH), London, UK
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