Articles: traumatic-brain-injuries.
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MicroRNAs (miRs) are small noncoding RNAs that negatively regulate gene expression at the post-transcriptional level. To identify miRs that may regulate neuronal cell death after experimental traumatic brain injury (TBI), we profiled miR expression changes during the first several days after controlled cortical impact (CCI) in mice. miR-23a and miR-27a were rapidly downregulated in the injured cortex in the first hour after TBI. These changes coincided with increased expression of the proapoptotic Bcl-2 family members Noxa, Puma, and Bax. ⋯ Importantly, administration of miR-23a and miR-27a mimics significantly reduced activation of Puma, Noxa, and Bax as well as attenuated markers of caspase-dependent and -independent apoptosis after TBI. Furthermore, miR-23a and miR-27a mimics significantly attenuated cortical lesion volume and neuronal cell loss in the hippocampus after TBI. These findings indicate that post-traumatic decreases in miR-23a and miR-27a contribute to neuronal cell death after TBI by upregulating proapoptotic Bcl-2 family members, thus providing a novel therapeutic target.
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Brain metabolism is thought to be maintained by neuronal-glial metabolic coupling. Glia take up glutamate from the synaptic cleft for conversion into glutamine, triggering glial glycolysis and lactate production. This lactate is shuttled into neurons and further metabolized. ⋯ Increased (13)C-labeled lactate in all study groups in the absence of ischemia implied activated astrocytic glycolysis and production of lactate with failure of neuronal uptake (i.e. a loss of glial sensing for glutamate). The early increase in extracellular lactate in severe TBI with the injured neurons rendered unable to pick it up probably contributes to a rapid progression toward irreversible injury and pan-necrosis. Hence, a method to detect and scavenge the excess extracellular lactate on site or early following severe TBI may be a potential primary therapeutic measure.
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Journal of neurotrauma · Jul 2014
Sleep problems and their relationship to cognitive and behavioral outcomes in young children with traumatic brain injury.
This study examined the effect of traumatic brain injury (TBI) in young children on sleep problems and the relationship of sleep problems to neuropsychological and psychosocial functioning. Participants were drawn from an ongoing longitudinal study of injury in young children recruited from 3 to 6 years of age. They constituted three groups: orthopedic injury (OI; n=92), complicated mild/moderate TBI (mTBI; n=55); and severe TBI (sTBI; n=20). ⋯ In contrast, sleep problems were generally not related to neuropsychological test performance. The results suggest that young children with TBI demonstrate more sleep problems than children with injuries not involving the head. Sleep problems, in turn, significantly increase the risk of poor psychosocial outcomes across time, but are not associated with worse neuropsychological test performance.
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Journal of neurotrauma · Jul 2014
Transport mode to level I and II trauma centers and survival of pediatric patients with traumatic brain injury.
The use of helicopter emergency medical services (EMS) for pediatric trauma patients is an issue of debate. We investigated the association of helicopter transport with survival of pediatric patients with traumatic brain injury (TBI). We conducted a retrospective cohort study of pediatric patients with TBI who were transported to level I and II trauma centers and were registered in the National Trauma Data Bank (NTDB) between 2009 and 2011. ⋯ Multivariable logistic regression analysis demonstrated an association of helicopter transport with increased survival (OR, 2.35; 95% CI, 1.30-4.25; ARR 5.36%). This again persisted after propensity score matching (OR 2.56; 95% CI 1.28-5.11; ARR 6.14). Pediatric patients with TBI transported to level I and II trauma centers had improved survival in comparison with similar patients transported via ground EMS.
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Journal of neurotrauma · Jul 2014
Using the Olfactory System as an in vivo Model to Study Traumatic Brain Injury and Repair.
Loss of olfactory function is an early indicator of traumatic brain injury (TBI). The regenerative capacity and well-defined neural maps of the mammalian olfactory system enable investigations into the degeneration and recovery of neural circuits after injury. Here, we introduce a unique olfactory-based model of TBI that reproduces many hallmarks associated with human brain trauma. ⋯ Behavioral experiments measured 4 days after impact also demonstrated loss of olfactory function, yet following a 30-day recovery period, we observed a significant improvement in olfactory function and partial recovery of olfactory circuitry, despite the persistence of TBI markers. Interestingly, by using the M71-IRES-tauLacZ reporter line to track OSN organization, we further determined that inducing neural activity during the recovery period with intense odor conditioning did not enhance the recovery process. Together, these data establish the mouse olfactory system as a new model to study TBI, serving as a platform to understand neural disruption and the potential for circuit restoration.