Autoantibodies to Glutamate Receptors and Products of Nitric Oxide Metabolism in Serum in Children in the Acute Phase of Craniocerebral Trauma

Complex Autoantibody Responses Occur following Moderate to Severe Traumatic Brain Injury

Most of the variation in outcome following severe traumatic brain injury (TBI) remains unexplained by currently recognized prognostic factors. Neuroinflammation may account for some of this difference. We hypothesized that TBI generated variable autoantibody responses between individuals that would contribute to outcome. We developed a custom protein microarray to detect autoantibodies to both CNS and systemic Ags in serum from the acute-phase (the first 7 d), late (6-12 mo), and long-term (6-13 y) intervals after TBI in human patients. We identified two distinct patterns of immune response to TBI. The first was a broad response to the majority of Ags tested, predominantly IgM mediated in the acute phase, then IgG dominant at late and long-term time points. The second was responses to specific Ags, most frequently myelin-associated glycopeptide (MAG), which persisted for several months post-TBI but then subsequently resolved. Exploratory analyses suggested that patients with a greater acute IgM response experienced worse outcomes than predicted from current known risk factors, suggesting a direct or indirect role in worsening outcome. Furthermore, late persistence of anti-MAG IgM autoantibodies correlated with raised serum neurofilament light concentrations at these time points, suggesting an association with ongoing neurodegeneration over the first year postinjury. Our results show that autoantibody production occurs in some individuals following TBI, can persist for many years, and is associated with worse patient outcome. The complexity of responses means that conventional approaches based on measuring responses to single antigenic targets may be misleading.

Brain Biomarkers in Children After Mild and Severe Traumatic Brain Injury

Brain biomarkers (protein S100b and neuron-specific enolase (NSE)), antibodies (aAb) to the NR2 subunit of N-methyl-D-aspartate (NR2(NMDA)) and to the GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (GluR1(AMPA)) subtype of glutamate receptors (GluR), NR2 and AMPA peptides, nitrogen oxides (NOx; "nitrites and nitrates"), and 3-nitrotyrosine (NT) were measured in blood from 159 children after mild traumatic brain injury (mTBI), moderate traumatic brain injury (mdTBI), or severe traumatic brain injury (sTBI) within 1-2 days and at intervals during the first 15 days after brain trauma. S100b and NSE levels on the first day were not a strict criterion for injury outcomes. Children with mTBI had the most significant elevations in antibodies to NR2(NMDA) and AMPA peptides, a slight increase in NOx, and, in 25% of cases, appearance of NT in the blood right after TBI. The lowest level of antibodies to NR2(NMDA) GluR detected shortly after the initial TBI was found in children with sTBI, with a negative outcome. The opposite characters of antibodies to NR2(NMDA) on the first day in children with mild and moderate versus severe TBI may be associated with an important mechanism aimed at protecting neurons from Glu excitotoxicity. We hypothesized that a slight increase in NOx after the onset of TBI rapidly activates the innate immune system and contributes to an increase in antibodies to NR2(NMDA). An increase in the AMPA peptide level in mTBI may be early signs of diffuse axonal injury.

[APOΕ gene polymorphism and markers of brain damage in the outcomes of severe traumatic brain injury in children]

OBJECTIVE

To compare apolipoprotein E (APOE) genotypes with outcomes and levels of neuromarkers in children with severe traumatic brain injury (TBI).

MATERIAL AND METHODS

APOE polymorphisms were genotyped in 69 children with severe TBI. The following markers of brain damage were identified: neuron-specific enolase (NSE), glial protein S100b, content of autoantibodies (aAB) to glutamate receptors (to the NR2 subunit of NMDA receptors), aAB to S100b and brain-derived neurotrophic factor (BDNF).

RESULTS AND CONCLUSION

There was no association between APOE 3/3, 3/4, 3/2 genotypes and outcomes assessed by the Glasgow Outcome Scale (GOS). The greatest number of favorable outcomes was noted in the group of APOE 3/3 genotype carriers (60%). The ratio of favorable outcomes to unfavorable outcomes was equal (50%:50%) in groups with APOE 3/4 and APOE 3/2 genotypes. An association between APOE polymorphism and BDNF was found: there were normal BDNF levels in the APOE 3/3 group and reduced levels in the APOE 3/2 group. The correlation between neuromarkers and GOS scores was shown for BDNF and aAB to S100b. In children with favorable TBI outcomes, normal BDNF levels and a lower level of aAB to S100b were observed. Regardless of APOE genotypes, almost all children with severe TBI (95%) showed a significant increase in aAB to glutamate receptors in the remote period and most children had an increase in aAB to S100b in the blood. This fact can be explained by the presence of cerebral hypoxia, activation of autoimmune processes and increased BBB permeability, which may be enhanced by increased NO content and intensification of oxidative processes in children with severe TBI.

Centers for Disease Control and Prevention Guideline on the Diagnosis and Management of Mild Traumatic Brain Injury Among Children

Importance

Mild traumatic brain injury (mTBI), or concussion, in children is a rapidly growing public health concern because epidemiologic data indicate a marked increase in the number of emergency department visits for mTBI over the past decade. However, no evidence-based clinical guidelines have been developed to date for diagnosing and managing pediatric mTBI in the United States.

Objective

To provide a guideline based on a previous systematic review of the literature to obtain and assess evidence toward developing clinical recommendations for health care professionals related to the diagnosis, prognosis, and management/treatment of pediatric mTBI.

Evidence Review

The Centers for Disease Control and Prevention (CDC) National Center for Injury Prevention and Control Board of Scientific Counselors, a federal advisory committee, established the Pediatric Mild Traumatic Brain Injury Guideline Workgroup. The workgroup drafted recommendations based on the evidence that was obtained and assessed within the systematic review, as well as related evidence, scientific principles, and expert inference. This information includes selected studies published since the evidence review was conducted that were deemed by the workgroup to be relevant to the recommendations. The dates of the initial literature search were January 1, 1990, to November 30, 2012, and the dates of the updated literature search were December 1, 2012, to July 31, 2015.

Findings

The CDC guideline includes 19 sets of recommendations on the diagnosis, prognosis, and management/treatment of pediatric mTBI that were assigned a level of obligation (ie, must, should, or may) based on confidence in the evidence. Recommendations address imaging, symptom scales, cognitive testing, and standardized assessment for diagnosis; history and risk factor assessment, monitoring, and counseling for prognosis; and patient/family education, rest, support, return to school, and symptom management for treatment.

Conclusions and Relevance

This guideline identifies the best practices for mTBI based on the current evidence; updates should be made as the body of evidence grows. In addition to the development of the guideline, CDC has created user-friendly guideline implementation materials that are concise and actionable. Evaluation of the guideline and implementation materials is crucial in understanding the influence of the recommendations.

Diagnosis and Management of Mild Traumatic Brain Injury in Children: A Systematic Review

IMPORTANCE

In recent years, there has been an exponential increase in the research guiding pediatric mild traumatic brain injury (mTBI) clinical management, in large part because of heightened concerns about the consequences of mTBI, also known as concussion, in children. The CDC National Center for Injury Prevention and Control's (NCIPC) Board of Scientific Counselors (BSC), a federal advisory committee, established the Pediatric Mild TBI Guideline workgroup to complete this systematic review summarizing the first 25 years of literature in this field of study.

OBJECTIVE

To conduct a systematic review of the pediatric mTBI literature to serve as the foundation for an evidence-based guideline with clinical recommendations associated with the diagnosis and management of pediatric mTBI.

EVIDENCE REVIEW

Using a modified Delphi process, the authors selected 6 clinical questions on diagnosis, prognosis, and management or treatment of pediatric mTBI. Two consecutive searches were conducted on PubMed, Embase, ERIC, CINAHL, and SportDiscus. The first included the dates January 1, 1990, to November 30, 2012, and an updated search included December 1, 2012, to July 31, 2015. The initial search was completed from December 2012 to January 2013; the updated search, from July 2015 to August 2015. Two authors worked in pairs to abstract study characteristics independently for each article selected for inclusion. A third author adjudicated disagreements. The risk of bias in each study was determined using the American Academy of Neurology Classification of Evidence Scheme. Conclusion statements were developed regarding the evidence within each clinical question, and a level of confidence in the evidence was assigned to each conclusion using a modified GRADE methodology. Data analysis was completed from October 2014 to May 2015 for the initial search and from November 2015 to April 2016 for the updated search.

FINDINGS

Validated tools are available to assist clinicians in the diagnosis and management of pediatric mTBI. A significant body of research exists to identify features that are associated with more serious TBI-associated intracranial injury, delayed recovery from mTBI, and long-term sequelae. However, high-quality studies of treatments meant to improve mTBI outcomes are currently lacking.

CONCLUSIONS AND RELEVANCE

This systematic review was used to develop an evidence-based clinical guideline for the diagnosis and management of pediatric mTBI. While an increasing amount of research provides clinically useful information, this systematic review identified key gaps in diagnosis, prognosis, and management.

Prognosis of Severe Traumatic Brain Injury Outcomes in Children

OBJECTIVES

We aimed to determine prognostic factors that can influence the outcome of severe traumatic brain injury (TBI) in children.

MATERIALS AND METHODS

One hundred and sixty-nine patients with severe TBI were included. Consciousness was evaluated using the Glasgow Coma Scale (GCS). Severity of concomitant injuries was evaluated using the Injury Severity Score (ISS). Computer tomography (CT) scanning was used on admission and later. Intracranial injuries were classified using the Marshall CT scale. Intracranial pressure (ICP) monitoring took place in 80 cases. Serum samples of 65 patients were tested for S-100β protein and of 43 patients for neuron specific enolase (NSE). Outcomes were evaluated 6 months after trauma using the Glasgow Outcome Scale (GOS). Statistical and mathematical analysis was conducted. The accuracy of our prognostic model was defined in another group of patients (n = 118).

RESULTS

GCS, pupil size and photoreaction, ISS, hypotension and hypoxia are significant predictors of outcome of severe TBI in children. CT results complement the forecast significantly. The accuracy of surviving prognosis came to 76% (0.76) in case of S-100β protein level ≤ 0.25 μg/l and NSE level < 19 μg/l. A mathematical model of outcome prognosis was based on discriminant function analysis. The model of prognosis was tested on the control group. The accuracy of prognosis was 86%.

CONCLUSIONS

A personalised prognostic model makes it possible to predict the outcome of severe TBI in children on the first day after trauma.

Functional, Structural, and Neurotoxicity Biomarkers in Integrative Assessment of Concussions

Concussion is a complex, heterogeneous process affecting the brain. Accurate assessment and diagnosis and appropriate management of concussion are essential to ensure that athletes do not prematurely return to play or others to work or active military duty, risking re-injury. To date, clinical diagnosis relies primarily on evaluating subjects for functional impairment using instruments that include neurocognitive testing, subjective symptom report, and neurobehavioral assessments, such as balance and vestibular-ocular reflex testing. Structural biomarkers, defined as advanced neuroimaging techniques and biomarkers assessing neurotoxicity and immunoexcitotoxicity, may complement the use of functional biomarkers. We hypothesize that neurotoxicity AMPA, NMDA, and kainite receptor biomarkers might be utilized as a part of comprehensive approach to concussion evaluations, with the goal of increasing diagnostic accuracy and facilitating treatment planning and prognostic assessment.