Journal of neurotrauma
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Journal of neurotrauma · Aug 2017
Environmental Enrichment Mitigates Deficits after Repetitive Mild TBI.
Although environmental enrichment has been shown to improve functional and histologic outcomes in pre-clinical moderate-to-severe traumatic brain injury (TBI), there are a paucity of pre-clinical data regarding enrichment strategies in the setting of repetitive mild traumatic brain injury (rmTBI). Given the vast numbers of athletes and those in the military who sustain rmTBI, the mounting evidence of the long-term and progressive sequelae of rmTBI, and the lack of targeted therapies to mitigate these sequelae, successful enrichment interventions in rmTBI could have large public health significance. Here, we evaluated enrichment strategies in an established pre-clinical rmTBI model. ⋯ Treatment with enrichment also corresponded to normal NMDAR subunit expression, decreased GluR1 phosphorylation, decreased phosphorylated CaMKII, and normal calpain expression post-rmTBI. These data suggest that enrichment strategies may improve functional outcomes and mitigate synaptic changes post-rmTBI. Given that enrichment strategies are feasible in the clinical setting, particularly for athletes and soldiers for whom the risk of repetitive injury is greatest, these data suggest that clinical trials may be warranted.
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Journal of neurotrauma · Aug 2017
Increased Expression of Epileptiform Spike/Wave Discharges One Year After Mild, Moderate, or Severe Fluid Percussion Brain Injury in Rats.
In this study, we describe increased expression of cortical epileptiform spike/wave discharges (SWD) in rats one year after mild, moderate, or severe fluid percussion traumatic brain injury (fpTBI). Groups of rats consisted of animals that had received mild, moderate, or severe fpTBI, or sham operation one year earlier than electrocorticography (ECoG) recordings. In addition, we included a group of age-matched naïve animals. ⋯ SWDs were observed to a lesser extent even in sham-operated and naïve animals. The data indicate that fpTBI exacerbates expression of SWDs in the rat and that this increase may be observed at least one year after injury. As others have discussed, the spontaneous occurrence of these epileptiform events in rodents limits the use of this model for investigations of acquired epilepsy, at least of the nonconvulsive type, after TBI.
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Journal of neurotrauma · Aug 2017
Observational StudyImpaired Cognitive Performance in Youth Athletes Exposed to Repetitive Head Impacts.
Worldwide, more than 22 million children and adolescents are exposed to repetitive head impacts (RHI) in soccer. Evidence indicates cumulative effects on brain structure, but it is not known whether exposure to RHI affects cognitive improvement in adolescents. The aim of the study was to determine whether exposure to RHI while heading the ball in soccer affects improvement in cognitive performance in adolescents over time. ⋯ Further, the more long headers performed, the slower the improvement in RT over the season. Youth athletes experience an immediate cognitive improvement after training most likely because of physical exercise. Results of this study also suggest an association between exposure to specific RHI (long headers) and lack of improvement in cognitive performance in youth athletes over time.
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Journal of neurotrauma · Aug 2017
Randomized Controlled TrialNeck collar with mild jugular vein compression ameliorates brain activation changes during a working memory task after a season of high school football.
Emerging evidence indicates that repetitive head impacts, even at a sub-concussive level, may result in exacerbated or prolonged neurological deficits in athletes. This study aimed to: 1) quantify the effect of repetitive head impacts on the alteration of neuronal activity based on functional magnetic resonance imaging (fMRI) of working memory after a high school football season; and 2) determine whether a neck collar that applies mild jugular vein compression designed to reduce brain energy absorption in head impact through "slosh" mitigation can ameliorate the altered fMRI activation during a working memory task. Participants were recruited from local high school football teams with 27 and 25 athletes assigned to the non-collar and collar group, respectively. ⋯ Areas displaying less activation change in the collar group (corrected p < 0.05) included the precuneus, inferior parietal cortex, and dorsal lateral prefrontal cortex. Additionally, BOLD response in the non-collar group increased significantly in direct association with the total number of impacts and total g-force (p < 0.05). Our data provide initial neuroimaging evidence for the effect of repetitive head impacts on the working memory related brain activity, as well as a potential protective effect that resulted from the use of the purported brain slosh reducing neck collar in contact sports.
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Journal of neurotrauma · Aug 2017
ReviewDNA methylation: Basic biology and application to traumatic brain injury.
This article reviews the literature pertinent to epigenetic changes, and in particular, DNA methylation following traumatic brain injury (TBI). TBI is a heterogeneous disease that is a major cause of death and long-term disability. The links between TBI and epigenetics, the process by which environmental factors alter gene expression without changing the underlying DNA sequence, is an expanding area of research that may have profound consequences for understanding the disease, and for clinical care. ⋯ Here, we briefly describe the interaction of DNA methylation with the two other key epigenetic changes, and highlight key work being performed to understand the functional relevance of those mechanisms. The field of epigenetics is rapidly advancing as a result of the advent of less invasive and more versatile methods for measuring epigenetic proteins and their functional impact on cells; however, the evidence specific to TBI is limited. This review identifies several important outstanding questions that remain from the work already conducted, and highlights directions for the future.