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Mondal K, Del Mar NA, Gary AA, Grambergs RC, Yousuf M, Tahia F, Stephenson B, Stephenson DJ, Chalfant CE, Reiner A, Mandal N. Sphingolipid changes in mouse brain and plasma after mild traumatic brain injury at the acute phases. Lipids Health Dis 2024; 23:200. [PMID: 38937745 PMCID: PMC11209960 DOI: 10.1186/s12944-024-02186-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 06/14/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) causes neuroinflammation and can lead to long-term neurological dysfunction, even in cases of mild TBI (mTBI). Despite the substantial burden of this disease, the management of TBI is precluded by an incomplete understanding of its cellular mechanisms. Sphingolipids (SPL) and their metabolites have emerged as key orchestrators of biological processes related to tissue injury, neuroinflammation, and inflammation resolution. No study so far has investigated comprehensive sphingolipid profile changes immediately following TBI in animal models or human cases. In this study, sphingolipid metabolite composition was examined during the acute phases in brain tissue and plasma of mice following mTBI. METHODS Wildtype mice were exposed to air-blast-mediated mTBI, with blast exposure set at 50-psi on the left cranium and 0-psi designated as Sham. Sphingolipid profile was analyzed in brain tissue and plasma during the acute phases of 1, 3, and 7 days post-TBI via liquid-chromatography-mass spectrometry. Simultaneously, gene expression of sphingolipid metabolic markers within brain tissue was analyzed using quantitative reverse transcription-polymerase chain reaction. Significance (P-values) was determined by non-parametric t-test (Mann-Whitney test) and by Tukey's correction for multiple comparisons. RESULTS In post-TBI brain tissue, there was a significant elevation of 1) acid sphingomyelinase (aSMase) at 1- and 3-days, 2) neutral sphingomyelinase (nSMase) at 7-days, 3) ceramide-1-phosphate levels at 1 day, and 4) monohexosylceramide (MHC) and sphingosine at 7-days. Among individual species, the study found an increase in C18:0 and a decrease in C24:1 ceramides (Cer) at 1 day; an increase in C20:0 MHC at 3 days; decrease in MHC C18:0 and increase in MHC C24:1, sphingomyelins (SM) C18:0, and C24:0 at 7 days. Moreover, many sphingolipid metabolic genes were elevated at 1 day, followed by a reduction at 3 days and an absence at 7-days post-TBI. In post-TBI plasma, there was 1) a significant reduction in Cer and MHC C22:0, and an increase in MHC C16:0 at 1 day; 2) a very significant increase in long-chain Cer C24:1 accompanied by significant decreases in Cer C24:0 and C22:0 in MHC and SM at 3 days; and 3) a significant increase of C22:0 in all classes of SPL (Cer, MHC and SM) as well as a decrease in Cer C24:1, MHC C24:1 and MHC C24:0 at 7 days. CONCLUSIONS Alterations in sphingolipid metabolite composition, particularly sphingomyelinases and short-chain ceramides, may contribute to the induction and regulation of neuroinflammatory events in the early stages of TBI, suggesting potential targets for novel diagnostic, prognostic, and therapeutic strategies in the future.
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Affiliation(s)
- Koushik Mondal
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
- Molecular Diagnostics Laboratory, Department of Basic & Translational Research, Saroj Gupta Cancer Centre & Research Institute, Kolkata, WB, 700 063, India
| | - Nobel A Del Mar
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Ashlyn A Gary
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Richard C Grambergs
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Mohd Yousuf
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Faiza Tahia
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Benjamin Stephenson
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Daniel J Stephenson
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Charles E Chalfant
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
- Research Service, Richmond VA Medical Center, Richmond, VA, 23298, USA
| | - Anton Reiner
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA
| | - Nawajes Mandal
- Department of Ophthalmology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA.
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA.
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Centre, Memphis, TN, 38163, USA.
- Memphis VA Medical Center, Memphis, TN, 38104, USA.
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Sinder SB, Sharma SV, Shirvaikar IS, Pradhyumnan H, Patel SH, Cabeda Diaz I, Perez GG, Bramlett HM, Raval AP. Impact of menopause-associated frailty on traumatic brain injury. Neurochem Int 2024; 176:105741. [PMID: 38621511 DOI: 10.1016/j.neuint.2024.105741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/01/2024] [Accepted: 04/09/2024] [Indexed: 04/17/2024]
Abstract
Navigating menopause involves traversing a complex terrain of hormonal changes that extend far beyond reproductive consequences. Menopausal transition is characterized by a decrease in estradiol-17β (E2), and the impact of menopause resonates not only in the reproductive system but also through the central nervous system, musculoskeletal, and gastrointestinal domains. As women undergo menopausal transition, they become more susceptible to frailty, amplifying the risk and severity of injuries, including traumatic brain injury (TBI). Menopause triggers a cascade of changes leading to a decline in muscle mass, accompanied by diminished tone and excitability, thereby restricting the availability of irisin, a crucial hormone derived from muscles. Concurrently, bone mass undergoes reduction, culminating in the onset of osteoporosis and altering the dynamics of osteocalcin, a hormone originating from bones. The diminishing levels of E2 during menopause extend their influence on the gut microbiota, resulting in a reduction in the availability of tyrosine, tryptophan, and serotonin metabolites, affecting neurotransmitter synthesis and function. Understanding the interplay between menopause, frailty, E2 decline, and the intricate metabolisms of bone, gut, and muscle is imperative when unraveling the nuances of TBI after menopause. The current review underscores the significance of accounting for menopause-associated frailty in the incidence and consequences of TBI. The review also explores potential mechanisms to enhance gut, bone, and muscle health in menopausal women, aiming to mitigate frailty and improve TBI outcomes.
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Affiliation(s)
- Sophie B Sinder
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Sabrina V Sharma
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Isha S Shirvaikar
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Hari Pradhyumnan
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Shahil H Patel
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Indy Cabeda Diaz
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Gina G Perez
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Helen M Bramlett
- Department of Neurological Surgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA; The Miami Project to Cure Paralysis, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA; Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL, USA
| | - Ami P Raval
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratory (CVDRL), Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA; Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL, USA
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Ding L, Patel A, Shankar S, Driscoll N, Zhou C, Rex TS, Vitale F, Gallagher MJ. An Open-Source Mouse Chronic EEG Array System with High-Density MXene-Based Skull Surface Electrodes. eNeuro 2024; 11:ENEURO.0512-22.2023. [PMID: 38388423 PMCID: PMC10884564 DOI: 10.1523/eneuro.0512-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 11/12/2023] [Accepted: 12/18/2023] [Indexed: 02/24/2024] Open
Abstract
Electroencephalography (EEG) is an indispensable tool in epilepsy, sleep, and behavioral research. In rodents, EEG recordings are typically performed with metal electrodes that traverse the skull into the epidural space. In addition to requiring major surgery, intracranial EEG is difficult to perform for more than a few electrodes, is time-intensive, and confounds experiments studying traumatic brain injury. Here, we describe an open-source cost-effective refinement of this technique for chronic mouse EEG recording. Our alternative two-channel (EEG2) and sixteen-channel high-density EEG (HdEEG) arrays use electrodes made of the novel, flexible 2D nanomaterial titanium carbide (Ti3C2T x ) MXene. The MXene electrodes are placed on the surface of the intact skull and establish an electrical connection without conductive gel or paste. Fabrication and implantation times of MXene EEG electrodes are significantly shorter than the standard approach, and recorded resting baseline and epileptiform EEG waveforms are similar to those obtained with traditional epidural electrodes. Applying HdEEG to a mild traumatic brain injury (mTBI) model in mice of both sexes revealed that mTBI significantly increased spike-wave discharge (SWD) preictal network connectivity with frequencies of interest in the β-spectral band (12-30 Hz). These findings indicate that the fabrication of MXene electrode arrays is a cost-effective, efficient technology for multichannel EEG recording in mice that obviates the need for skull-penetrating surgery. Moreover, increased preictal β-frequency network connectivity may contribute to the development of early post-mTBI SWDs.
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Affiliation(s)
- Li Ding
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Aashvi Patel
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Sneha Shankar
- Departments of Bioengineering and Neurology, Center for Neuroengineering & Therapeutics, University of Pennsylvania, Philadelphia 19104, Pennsylvania
| | - Nicolette Driscoll
- Departments of Bioengineering and Neurology, Center for Neuroengineering & Therapeutics, University of Pennsylvania, Philadelphia 19104, Pennsylvania
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Tonia S Rex
- Department of Ophthalmology & Visual Sciences, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
| | - Flavia Vitale
- Departments of Bioengineering and Neurology, Center for Neuroengineering & Therapeutics, University of Pennsylvania, Philadelphia 19104, Pennsylvania
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia 19104, Pennsylvania
| | - Martin J Gallagher
- Department of Neurology, Vanderbilt University School of Medicine, Nashville 37232, Tennessee
- Department of Veteran's Affairs, Tennessee Valley Health System, Nashville 37212, Tennessee
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Martini DN, Gera G, Brumbach BH, Campbell KR, Parrington L, Chesnutt J, King LA. Symptoms and Central Sensory Integration in People With Chronic mTBI: Clinical Implications. Mil Med 2023; 188:3553-3560. [PMID: 35657326 PMCID: PMC10629982 DOI: 10.1093/milmed/usac157] [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: 02/18/2022] [Revised: 04/27/2022] [Accepted: 05/18/2022] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION Balance deficits in people with chronic mild traumatic brain injury (mTBI; ≥3 months post-mTBI), thought to relate to central sensory integration deficits, are subtle and often difficult to detect. The purpose of this study was to determine the sensitivity of the instrumented modified clinical test of sensory integration for balance (mCTSIB) in identifying such balance deficits in people with symptomatic, chronic mTBI and to establish the associations between balance and mTBI symptom scores in the chronic mTBI group. METHODS The Institutional Review Board approved these study methods. Forty-one people with chronic mTBI and balance complaints and 53 healthy controls performed the mCTSIB (eyes open/closed on firm/foam surfaces; EoFi, EcFi, EoFo, and EcFo) with a wearable sensor on their waist to quantify sway area (m2/s4). Sensory reweighting variables were calculated for the firm and foam stance conditions. A stopwatch provided the clinical outcome for the mCTSIB (time). Each participant completed the Neurobehavioral Symptom Inventory (NSI), which quantifies mTBI-related symptoms and provides a total score, as well as sub-scores on affective, cognitive, somatic, and vestibular domains. RESULTS The mTBI group reported significantly higher symptom scores across each NSI sub-score (all Ps < .001). The mTBI group had a significantly larger sway area than the control group across all mCTSIB conditions and the mTBI group had significantly higher sensory reweighting scores compared to the control group on both the firm (P = .01) and foam (P = .04) surfaces. Within the mTBI group, the NSI vestibular score significantly related to the mCTSIB sway area EcFi (r = 0.38; P = .02), sway area EcFo (r = 0.43; P = .006), sensory reweighting firm (r = 0.33; P = .04), and sensory reweighting foam (r = 0.38; P = .02). The average sway area across the 4 mCTSIB conditions was significantly (area under the curve: 0.77; P < .001) better at differentiating groups than the mCTSIB clinical total score. The average sway area across the 4 mCTSIB conditions had a sensitivity of 73% and a specificity of 71%. The clinical mCTSIB outcome scores were not different between groups. CONCLUSION People with chronic mTBI appear to have central sensory integration deficits detectable by instrumented measures of postural assessment. These findings suggest that central sensory integration should be targeted in rehabilitation for people with chronic mTBI.
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Affiliation(s)
- Douglas N Martini
- Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Geetanjali Gera
- Department of Physical Therapy, University of Kentucky, Lexington, KY 40536, USA
| | - Barbara H Brumbach
- Biostatistics and Design Program, Oregon Health & Science University, Portland, OR 97239, USA
| | - Kody R Campbell
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
- National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Healthcare System, Portland, OR 97239, USA
| | - Lucy Parrington
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
- National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Healthcare System, Portland, OR 97239, USA
- Department of Dietetics, Human Nutrition and Sport, La Trobe University, Bundoora, VIC 3086, Australia
| | - James Chesnutt
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
- Department of Family Medicine and Orthopedics & Rehabilitation, Oregon Health & Science University, Portland, OR 97239, USA
| | - Laurie A King
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
- National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Healthcare System, Portland, OR 97239, USA
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Honig MG, Del Mar NA, Moore BM, Reiner A. Raloxifene Mitigates Emotional Deficits after Mild Traumatic Brain Injury in Mice. Neurotrauma Rep 2022; 3:534-544. [DOI: 10.1089/neur.2022.0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Marcia G. Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Nobel A. Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Bob M. Moore
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
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6
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Honig MG, Del Mar NA, Henderson DL, O'Neal D, Yammanur M, Cox R, Li C, Perry AM, Moore BM, Reiner A. Raloxifene, a cannabinoid type-2 receptor inverse agonist, mitigates visual deficits and pathology and modulates microglia after ocular blast. Exp Eye Res 2022; 218:108966. [PMID: 35143834 DOI: 10.1016/j.exer.2022.108966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/04/2022] [Accepted: 01/24/2022] [Indexed: 11/19/2022]
Abstract
Visual deficits after ocular blast injury (OBI) are common, but pharmacological approaches to improve long-term outcomes have not been identified. Blast forces frequently damage the retina and optic nerves, and work on experimental animals has shown the pro-inflammatory actions of microglia can further exacerbate such injuries. Cannabinoid type-2 receptor (CB2) inverse agonists specifically target activated microglia, biasing them away from the harmful pro-inflammatory M1 state toward the helpful reparative M2 state. We previously found that treating mice with CB2 inverse agonists after traumatic brain injury, produced by either focal cranial air blast or dorsal cranial impact, greatly attenuated the visual deficits and pathology that otherwise resulted. Here we examined the consequences of single and repeat OBI and the benefit provided by raloxifene, an FDA-approved estrogen receptor drug that possesses noteworthy CB2 inverse agonism. After single OBI, although the amplitudes of the A- and B-waves of the electroretinogram and pupil light response appeared to be normal, the mice showed hints of deficits in contrast sensitivity and visual acuity, a trend toward optic nerve axon loss, and significantly increased light aversion, which were reversed by 2 weeks of daily treatment with raloxifene. Mice subjected to repeat OBI (5 blasts spaced 1 min apart), exhibited more severe visual deficits, including decreases in contrast sensitivity, visual acuity, the amplitudes of the A- and B-waves of the electroretinogram, light aversion, and resting pupil diameter (i.e. hyperconstriction), accompanied by the loss of photoreceptor cells and optic nerve axons, nearly all of which were mitigated by raloxifene. Interestingly, optic nerve axon abundance was strongly correlated with contrast sensitivity and visual acuity across all groups of experimental mice in the repeat OBI study, suggesting optic nerve axon loss with rOBI and its attenuation with raloxifene are associated with the extent of these two deficits while photoreceptor abundance was highly correlated with A-wave amplitude and resting pupil size, suggesting a prominent role for photoreceptors in these two deficits. Quantitative PCR (qPCR) showed levels of M1-type microglial markers (e.g. iNOS, IL1β, TNFα, and CD32) in retina, optic nerve, and thalamus were increased 3 days after repeat OBI. With raloxifene treatment, the overall expression of M1 markers was more similar to that in sham mice. Raloxifene treatment was also associated with the elevation of IL10 transcripts in all three tissues compared to repeat OBI alone, but the results for the three other M2 microglial markers we examined were more varied. Taken together, the qPCR results suggest that raloxifene benefit for visual function and pathology was associated with a lessening of the pro-inflammatory actions of microglia. The benefit we find for raloxifene following OBI provides a strong basis for phase-2 efficacy testing in human clinical trials for treating ocular injury.
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Affiliation(s)
- Marcia G Honig
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Nobel A Del Mar
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Desmond L Henderson
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Dylan O'Neal
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Meghna Yammanur
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Rachel Cox
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Chunyan Li
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Aaron M Perry
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Bob M Moore
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology(,) the University of Tennessee Health Science Center, Memphis, TN, 38163, USA; Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
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Boucher ML, Conley G, Nowlin J, Qiu J, Kawata K, Bazarian JJ, Meehan WP, Mannix R. Titrating the Translational Relevance of a Low-Level Repetitive Head Impact Model. Front Neurol 2022; 13:857654. [PMID: 35785366 PMCID: PMC9246060 DOI: 10.3389/fneur.2022.857654] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Recently, there has been increased attention in the scientific community to the phenomenon of sub-concussive impacts, those hits to the head that do not cause the signs and symptoms of a concussion. Some authors suggest that sub-concussive impacts may alter behavior and cognition, if sustained repetitively, but the mechanisms underlying these changes are not well-defined. Here, we adapt our well-established weight drop model of repetitive mild traumatic brain injury (rmTBI) to attempt to produce a model of low-level repetitive head impacts (RHI). The model was modified to eliminate differences in latency to right following impact and gross behavioral changes after a single cluster of hits. Further, we varied our model in terms of repetition of impact over a 4-h span to mimic the repeated sub-concussive impacts that may be experienced by an athlete within a single day of play. To understand the effects of a single cluster of RHIs, as well as the effect of an increased impact frequency within the cluster, we evaluated classical behavioral measures, serum biomarkers, cortical protein quantification, and immunohistochemistry both acutely and sub-acutely following the impacts. In the absence of gross behavioral changes, the impact protocol did generate pathology, in a dose-dependent fashion, in the brain. Evaluation of serum biomarkers revealed limited changes in GFAP and NF-L, which suggests that their diagnostic utility may not emerge until the exposure to low-level head impacts reaches a certain threshold. Robust decreases in both IL-1β and IL-6 were observed in the serum and the cortex, indicating downregulation of inflammatory pathways. These experiments yield initial data on pathology and biomarkers in a mouse model of low-level RHIs, with relevance to sports settings, providing a starting point for further exploration of the potential role of anti-inflammatory processes in low-level RHI outcomes, and how these markers may evolve with repeated exposure.
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Affiliation(s)
- Masen L Boucher
- Harvard Medical School, Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Grace Conley
- Harvard Medical School, Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Jordan Nowlin
- Harvard Medical School, Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, United States
| | - Jianhua Qiu
- Harvard Medical School, Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
| | - Keisuke Kawata
- Department of Kinesiology, Indiana University, Bloomington, IN, United States
| | - Jeffrey J Bazarian
- Department of Emergency Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - William P Meehan
- Department of Pediatrics, Harvard Medical School, Boston, MA, United States.,Harvard Medical School, Division of Sports Medicine, Boston Children's Hospital, Boston, MA, United States.,The Micheli Center for Sports Injury Prevention, Waltham, MA, United States
| | - Rebekah Mannix
- Harvard Medical School, Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
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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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Majewska AK, Verkhratsky A, Hughes EG. Special issue editorial: Glial plasticity in health and disease. Eur J Neurosci 2021; 54:5643-5648. [PMID: 34363271 DOI: 10.1111/ejn.15414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 11/27/2022]
Affiliation(s)
- Ania K Majewska
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.,Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA
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Abd-El-Basset EM, Rao MS, Alsaqobi A. Interferon-Gamma and Interleukin-1Beta Enhance the Secretion of Brain-Derived Neurotrophic Factor and Promotes the Survival of Cortical Neurons in Brain Injury. Neurosci Insights 2020; 15:2633105520947081. [PMID: 32776009 PMCID: PMC7391446 DOI: 10.1177/2633105520947081] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/14/2020] [Indexed: 12/28/2022] Open
Abstract
Neuro-inflammation is associated with the production of cytokines, which influence neuronal and glial functions. Although the proinflammatory cytokines interferon-γ (IFN-γ) and interleukin-1Beta (IL-1β) are thought to be the major mediators of neuro-inflammation, their role in brain injury remains ill-defined. The objective of this study was to examine the effect of IFN-γ and IL-1β on survival of cortical neurons in stab wound injury in mice. A stab wound injury was made in the cortex of male BALB/c mice. Injured mice (I) were divide into IFN-γ and IL-1β treatment experiments. Mice in I + IFN-γ group were treated with IFN-γ (ip, 10 µg/kg/day) for 1, 3 and 7 days and mice in I + IL-1β group were treated with 5 IP injection of IL-1β (0.5 µg /12 h). Appropriate control mice were maintained for comparison. Immunostaining of frozen brain sections for astrocytes (GFAP), microglia (Iba-1) and Fluoro-Jade B staining for degenerating neurons were used. Western blotting and ELISA for brain-derived neurotrophic factor (BDNF) were done on the tissues isolated from the injured sites. Results showed a significant increase in the number of both astrocytes and microglia in I + IFN-γ and I + IL-1β groups. There were no significant changes in the number of astrocytes or microglia in noninjury groups (NI) treated with IFN-γ or IL-1β. The number of degenerating neurons significantly decreased in I + IFN-γ and I + IL-1β groups. GFAP and BDNF levels were significantly increased in I + IFN-γ and I + IL-1β groups. Interferon-γ and IL-1β induce astrogliosis, microgliosis, enhance the secretion of BDNF, one of the many neurotrophic factors after brain injury, and promote the survival of cortical neurons in stab wound brain injury.
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