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  1. Article ; Online: Time-Dependent Long-Term Effect of Memantine following Repetitive Mild Traumatic Brain Injury.

    Boucher, Masen L / Conley, Grace / Morriss, Nicholas J / Ospina-Mora, Sara / Qiu, Jianhua / Mannix, Rebekah / Meehan, William P

    Journal of neurotrauma

    2024  

    Abstract: Repetitive mild traumatic brain injury (rmTBI, e.g., sports concussions) may be associated with both acute and chronic symptoms and neurological changes. Despite the common occurrence of these injuries, therapeutic strategies are limited. One potentially ...

    Abstract Repetitive mild traumatic brain injury (rmTBI, e.g., sports concussions) may be associated with both acute and chronic symptoms and neurological changes. Despite the common occurrence of these injuries, therapeutic strategies are limited. One potentially promising approach is N-methyl-D-aspartate receptor (NMDAR) blockade to alleviate the effects of post-injury glutamatergic excitotoxicity. Initial pre-clinical work using the NMDAR antagonist, memantine, suggests that immediate treatment following rmTBI improves a variety of acute outcomes. It remains unclear (1) whether acute memantine treatment has long-term benefits and (2) whether delayed treatment following rmTBI is beneficial, which are both clinically relevant concerns. To test this, animals were subjected to rmTBI via a weight drop model with rotational acceleration (five hits in 5 days) and randomized to memantine treatment immediately, 3 months, or 6 months post-injury, with a treatment duration of one month. Behavioral outcomes were assessed at 1, 4, and 7 months post-injury. Neuropathological outcomes were characterized at 7 months post-injury. We observed chronic changes in behavior (anxiety-like behavior, motor coordination, spatial learning, and memory), as well as neuroinflammation (microglia, astrocytes) and tau phosphorylation (T231). Memantine treatment, either immediately or 6 months post-injury, appears to confer greater rescue of neuroinflammatory changes (microglia) than vehicle or treatment at the 3-month time point. Although memantine is already being prescribed chronically to address persistent symptoms associated with rmTBI, this study represents the first evidence of which we are aware to suggest a small but durable effect of memantine treatment in mild, concussive injuries. This effect suggests that memantine, although potentially beneficial, is insufficient to treat all aspects of rmTBI alone and should be combined with other therapeutic agents in a multi-therapy approach, with attention given to the timing of treatment.
    Language English
    Publishing date 2024-05-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 645092-1
    ISSN 1557-9042 ; 0897-7151
    ISSN (online) 1557-9042
    ISSN 0897-7151
    DOI 10.1089/neu.2023.0423
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Optimizing Choice and Timing of Behavioral Outcome Tests After Repetitive Mild Traumatic Brain Injury: A Machine Learning-Based Approach on Multiple Pre-Clinical Experiments.

    Lassarén, Philipp / Conley, Grace / Boucher, Masen L / Conley, Ashley N / Morriss, Nicholas J / Qiu, Jianhua / Mannix, Rebekah C / Thelin, Eric Peter

    Journal of neurotrauma

    2023  Volume 40, Issue 15-16, Page(s) 1762–1778

    Abstract: Repetitive mild traumatic brain injury (rmTBI) is a potentially debilitating condition with long-term sequelae. Animal models are used to study rmTBI in a controlled environment, but there is currently no established standard battery of behavioral tests ... ...

    Abstract Repetitive mild traumatic brain injury (rmTBI) is a potentially debilitating condition with long-term sequelae. Animal models are used to study rmTBI in a controlled environment, but there is currently no established standard battery of behavioral tests used. Primarily, we aimed to identify the best combination and timing of behavioral tests to distinguish injured from uninjured animals in rmTBI studies, and secondarily, to determine whether combinations of independent experiments have better behavioral outcome prediction accuracy than individual experiments. Data from 1203 mice from 58 rmTBI experiments, some of which have already been published, were used. In total, 11 types of behavioral tests were measured by 37 parameters at 13 time points during the first 6 months after injury. Univariate regression analyses were used to identify optimal combinations of behavioral tests and whether the inclusion of multiple heterogenous experiments improved accuracy.
    MeSH term(s) Mice ; Animals ; Brain Concussion/diagnosis ; Brain Concussion/complications ; Maze Learning ; Models, Animal ; Behavior, Animal ; Disease Models, Animal
    Language English
    Publishing date 2023-03-21
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 645092-1
    ISSN 1557-9042 ; 0897-7151
    ISSN (online) 1557-9042
    ISSN 0897-7151
    DOI 10.1089/neu.2022.0486
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Titrating the Translational Relevance of a Low-Level Repetitive Head Impact Model.

    Boucher, Masen L / Conley, Grace / Nowlin, Jordan / Qiu, Jianhua / Kawata, Keisuke / Bazarian, Jeffrey J / Meehan, William P / Mannix, Rebekah

    Frontiers in neurology

    2022  Volume 13, Page(s) 857654

    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 ... ...

    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.
    Language English
    Publishing date 2022-06-16
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564214-5
    ISSN 1664-2295
    ISSN 1664-2295
    DOI 10.3389/fneur.2022.857654
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Preclinical characterization of macrophage-adhering gadolinium micropatches for MRI contrast after traumatic brain injury in pigs.

    Wang, Lily Li-Wen / Gao, Yongsheng / Chandran Suja, Vineeth / Boucher, Masen L / Shaha, Suyog / Kapate, Neha / Liao, Rick / Sun, Tao / Kumbhojkar, Ninad / Prakash, Supriya / Clegg, John R / Warren, Kaitlyn / Janes, Morgan / Park, Kyung Soo / Dunne, Michael / Ilelaboye, Bolu / Lu, Andrew / Darko, Solomina / Jaimes, Camilo /
    Mannix, Rebekah / Mitragotri, Samir

    Science translational medicine

    2024  Volume 16, Issue 728, Page(s) eadk5413

    Abstract: The choroid plexus (ChP) of the brain plays a central role in orchestrating the recruitment of peripheral leukocytes into the central nervous system (CNS) through the blood-cerebrospinal fluid (BCSF) barrier in pathological conditions, thus offering a ... ...

    Abstract The choroid plexus (ChP) of the brain plays a central role in orchestrating the recruitment of peripheral leukocytes into the central nervous system (CNS) through the blood-cerebrospinal fluid (BCSF) barrier in pathological conditions, thus offering a unique niche to diagnose CNS disorders. We explored whether magnetic resonance imaging of the ChP could be optimized for mild traumatic brain injury (mTBI). mTBI induces subtle, yet influential, changes in the brain and is currently severely underdiagnosed. We hypothesized that mTBI induces sufficient alterations in the ChP to cause infiltration of circulating leukocytes through the BCSF barrier and developed macrophage-adhering gadolinium [Gd(III)]-loaded anisotropic micropatches (GLAMs), specifically designed to image infiltrating immune cells. GLAMs are hydrogel-based discoidal microparticles that adhere to macrophages without phagocytosis. We present a fabrication process to prepare GLAMs at scale and demonstrate their loading with Gd(III) at high relaxivities, a key indicator of their effectiveness in enhancing image contrast and clarity in medical imaging. In vitro experiments with primary murine and porcine macrophages demonstrated that GLAMs adhere to macrophages also under shear stress and did not affect macrophage viability or functions. Studies in a porcine mTBI model confirmed that intravenously administered macrophage-adhering GLAMs provide a differential signal in the ChP and lateral ventricles at Gd(III) doses 500- to 1000-fold lower than those used in the current clinical standard Gadavist. Under the same mTBI conditions, Gadavist did not offer a differential signal at clinically used doses. Our results suggest that macrophage-adhering GLAMs could facilitate mTBI diagnosis.
    MeSH term(s) Animals ; Mice ; Swine ; Gadolinium ; Brain Injuries, Traumatic/diagnostic imaging ; Brain/pathology ; Magnetic Resonance Imaging/methods ; Brain Concussion/pathology ; Macrophages/pathology
    Chemical Substances Gadolinium (AU0V1LM3JT)
    Language English
    Publishing date 2024-01-03
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2518854-9
    ISSN 1946-6242 ; 1946-6234
    ISSN (online) 1946-6242
    ISSN 1946-6234
    DOI 10.1126/scitranslmed.adk5413
    Database MEDical Literature Analysis and Retrieval System OnLINE

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