Journal of neurotrauma
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Journal of neurotrauma · Oct 2013
Association between the Cerebral Inflammatory and Matrix Metalloproteinase Responses after Severe Traumatic Brain Injury in Humans.
An increasing number of preclinical investigations have suggested that the degree of expression of the matrix metalloproteinase (MMP) family of endopeptidases may explain some of the variability in neurological damage after traumatic brain injury (TBI). As cytokines are a prominent stimulus for MMP expression in animals, we conducted a prospective multimodal monitoring study and determined their association with temporal MMP expression after severe TBI in eight critically ill adults. High cutoff, cerebral microdialysis (n=8); external ventricular drainage (n=3); and arterial and jugular venous bulb catheters were used to measure the concentration of nine cytokines and eight MMPs in microdialysate, cerebrospinal fluid (CSF), and plasma over 6 days. ⋯ In contrast, the microdialysate level of MMP-7 decreased with increases in microdialysate concentrations of IL-1β, -2, and -6. These findings support the observations of animal studies that cross-talk exists between the neuroinflammatory and MMP responses after acute brain injury. Further study is needed to determine whether this link between cerebral inflammation and MMP expression may have clinical relevance to the care of patients with TBI.
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Journal of neurotrauma · Oct 2013
Episodic Memory in Former Professional Football Players with a History of Concussion: An Event-Related Functional Neuroimaging Study.
Previous research has demonstrated that sport-related concussions can have short-term effects on cognitive processes, but the long-term consequences are less understood and warrant more research. This study was the first to use event-related functional magnetic resonance imaging (fMRI) to examine long-term differences in neural activity during memory tasks in former athletes who have sustained multiple sport-related concussions. In an event-related fMRI study, former football players reporting multiple sport-related concussions (i.e., three or more) were compared with players who reported fewer than three concussions during a memory paradigm examining item memory (i.e., memory for the particular elements of an event) and relational memory (i.e., memory for the relationships between elements). ⋯ Despite demonstrating equivalent behavioral performance, the two groups of former players demonstrated different neural recruitment patterns during relational memory retrieval, suggesting that multiple concussions may be associated with functional inefficiencies in the relational memory network. In addition, the number of previous concussions significantly correlated with functional activity in a number of brain regions, including the medial temporal lobe and inferior parietal lobe. Our results provide important insights in understanding the long-term functional consequences of sustaining multiple sports-related concussions.
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Journal of neurotrauma · Oct 2013
Cytokine Gene Polymorphisms and Outcome after Traumatic Brain Injury.
Clinical outcome after traumatic brain injury (TBI) is variable and cannot easily be predicted. There is increasing evidence to suggest that there may be genetic influences on outcome. Cytokines play an important role in mediating the inflammatory response provoked within the central nervous system after TBI. ⋯ In an initial screen of 11 cytokine gene single nucleotide polymorphisms (SNPs) previously associated with disease susceptibility or outcome (TNFA -238 and -308, IL6 -174, -572 and -597, IL1A -889, IL1B -31, -511 and +3953, and TGFB -509 and -800), TNFA -308 was identified as having a likely association. The TNFA -308 SNP was further evaluated, and a significant association was identified, with 39% of allele 2 carriers having an unfavorable outcome compared with 31% of non-carriers (adjusted odds ratio 1.67, confidence interval 1.19-2.35, p=0.003). These findings are consistent with experimental and clinical data suggesting that neuroinflammation has an impact on clinical outcome after TBI and that tumor necrosis factor alpha plays an important role in this process.
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Journal of neurotrauma · Oct 2013
S100B Protein May Detect Brain Death Development after Severe Traumatic Brain Injury.
Despite improvements in the process of organ donation and transplants, the number of organ donors is progressively declining in developed countries. Therefore, the early detection of patients at risk for brain death (BD) is a priority for transplant teams seeking more efficient identification of potential donors. In the extensive literature on S100B as a biomarker for traumatic brain injury (TBI), no evidence appears to exist on its prognostic capacity as a predictor of BD after severe TBI. ⋯ Receiver operating characteristics (ROC) curve analysis on this group showed the highest area under the curve (AUC) (0.86; p=0.001) for 24 h S100B determinations. The cut off was set at 0.372 μg/L (85.7% sensitivity, 79.3% specificity, positive predictive value [PPV]=18.7% and negative predictive value [NPV]=98.9%). This study shows that pupillary responsiveness at admission, as well as 24 h serum S100B levels, could serve as screening tools for the early detection of patients at risk for BD after severe TBI.
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Journal of neurotrauma · Oct 2013
Complexity Analysis of Resting State Magnetoencephalography Activity in Traumatic Brain Injury Patients.
Diagnosis of mild traumatic brain injuries (TBIs) has been difficult because of the absence of obvious focal brain lesions, using conventional computed tomography (CT) or magnetic resonance imaging (MRI) scans, in a large percentage of TBIs. One useful measure that can characterize potential tissue and neural network damage objectively is Lempel-Ziv complexity (LZC) applied to magnetoencephalography (MEG) signals. LZC is a model-independent estimator of system complexity that estimates the number of different patterns in a sequence. ⋯ Resting state MEG data were acquired, and the LZCs were analyzed across the whole brain. Our results indicated reduced complexity in multiple brain areas in TBI patients relative to the healthy controls. In addition, we detected several neuropsychological measures associated with motor responses, visual perception, and memory, correlated with LZC, which likely explains some of the cognitive deficits in TBI patients.