Journal of neurotrauma
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Journal of neurotrauma · Feb 2017
Disrupted white matter microstructure and mood disorders following traumatic brain injury.
Traumatic brain injury (TBI) is associated with an elevated frequency of mood disorders that may, in part, be explained by changes in white-matter microstructure. This study is the first to examine the relationship between mood disorders and white-matter pathology in a sample of patients with mild to severe TBI using a standardized psychiatric interview. This study reports on a sub-sample of 29 individuals recruited from a large prospective study that examined the evolution of psychiatric disorders following complicated, mild to severe TBI. ⋯ The pattern of white matter disruption identified in the current study provides further support for a neurobiological basis of post-TBI mood disorders. Greater understanding of individuals' underlying neuropathology may enable better characterization and prediction of mood disorders. Integration of neuropathology may also inform the potential efficacy of pharmacological and psychological interventions.
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Journal of neurotrauma · Feb 2017
Abnormalities in functional connectivity in collegiate football athletes with and without a concussion history: implications and role of neuroactive kynurenine pathway metabolites.
There is a great need to identify potential long-term consequences of contact sport exposure and to identify molecular pathways that may be associated with these changes. We tested the hypothesis that football players with (Ath-mTBI) (n = 25) and without a concussion history (Ath) (n = 24) have altered resting state functional connectivity in regions with previously documented structural changes relative to healthy controls without football or concussion history (HC) (n = 27). As a secondary aim, we tested the hypothesis that group differences in functional connectivity are moderated by the relative ratio of neuroprotective to neurotoxic metabolites of the kynurenine pathway. ⋯ In contrast, both Ath-mTBI and Ath had increased connectivity between the left orbital frontal cortex and the right lateral frontal cortex, and between the left cornu ammonis areas 2 and 3/dentate gyrus (CA2-3/DG) of the hippocampus and the middle and posterior cingulate cortices, relative to HC. The relationship between the ratio of plasma concentrations of kynurenic acid to quinolinic acid (KYNA/QUIN) and left pregenual anterior cingulate cortex connectivity to multiple regions as well as KYNA/QUIN and right CA2-3/DG connectivity to multiple regions differed significantly according to football and concussion history. The results suggest that football exposure with and without concussion history can have a significant effect on intrinsic brain connectivity and implicate the kynurenine metabolic pathway as one potential moderator of functional connectivity dependent on football exposure and concussion history.
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Journal of neurotrauma · Feb 2017
Brain structure and function associated with a history of sport concussion: a multi-modal MRI study.
There is growing concern about the potential long-term consequences of sport concussion for young, currently active athletes. However, there remains limited information about brain abnormalities associated with a history of concussion and how they relate to clinical factors. In this study, advanced MRI was used to comprehensively describe abnormalities in brain structure and function associated with a history of sport concussion. ⋯ White matter showed limited correlations with clinical factors, predominantly in the anterior corona radiata. This study provides the first evidence of the long-term effects of concussion on gray matter volume, blood flow, and white matter microstructure within a single athlete cohort. This was examined for a mixture of male and female athletes in both contact and noncontact sports, demonstrating the relevance of these findings for the overall sporting community.
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Journal of neurotrauma · Feb 2017
Blood aggravates histological and functional damage after acute subdural hematoma in rats.
Acute subdural hematoma (ASDH) is associated with high morbidity and mortality. Whether the volume effect of the hematoma and increase of intracranial pressure (ICP) or the local effect of blood are responsible for this severe pathophysiology is unclear. Therefore, we compared subdural infusion of autologous blood and paraffin oil in a rat model of ASDH. ⋯ In the behavioral evaluation, paraffin-infused animals showed a better recovery, compared with the blood infusion group. In conclusion, comparable acute time-course of ICP, CPP, and CBF clearly indicates that the differences in lesion size, inflammatory reaction, and behavioral deficits after blood- and paraffin oil-induced ASDH are partially due to blood constituents. Therefore, current data suggest that subdural hematomas should be completely removed as quickly as possible; decompression alone may not be sufficient to prevent secondary brain damage.
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Journal of neurotrauma · Feb 2017
Memantine reduced cell death, astrogliosis, and functional deficits in an in vitro model of repetitive mild traumatic brain injury.
Clinical studies suggest that athletes with a history of concussion may be at risk for additional mild traumatic brain injury (mTBI), and repetitive exposure to mTBI acutely increases risk for more significant and persistent symptoms and increases future risk for developing neurodegenerative diseases. Currently, symptoms of mTBI are managed with rest and pain medication; there are no drugs approved by the Food and Drug Administration (FDA) that target the biochemical pathology underlying mTBI to treat or prevent acute and long-term effects of repetitive mTBI. Memantine is an FDA-approved drug for treating Alzheimer's disease, and also was shown to be neuroprotective in rodents following a single, moderate to severe TBI. ⋯ Samples received two injuries 24 h apart; injury resulted in significant cell death, loss of long-term potentiation (LTP), and astrogliosis compared with naïve, uninjured samples. Delivery of 1.5 μM memantine 1 h following each stretch significantly reduced the effect of injury for all outcome measures, and did not alter those outcome measures that were unaffected by the injury. Therefore, memantine warrants further pre-clinical and clinical investigation for its therapeutic efficacy to prevent cognitive deficits and neuropathology from multiple mTBIs.