Brain injury biomarkers as outcome predictors in pediatric severe traumatic brain injury

Lactic acid, neuron-specific enolase, and blood-brain barrier index after a severe traumatic brain injury: a prospective study

OBJECTIVE

To explore the clinical significance of dynamic monitoring of cerebrospinal fluid (CSF) and serum Lactic acid（Lac), neuron-specific enolase (NSE), and the blood-brain barrier (BBB) index in evaluating the condition and prognosis after a severe traumatic brain injury (TBI).

METHODS

A total of 52 severe TBI patients admitted to the Department of Neurosurgery within 24 hours after injury were dynamically monitored. CSF and serum samples were collected on the 1st, 3rd, and 7th day after a severe TBI to monitor the changes in Lac, NSE, and the BBB index. Intracranial pressure (ICP), Glasgow coma scale (GCS), and 6-month Glasgow outcome scale-extended (GOS-E) were tested. According to the results of GOS-E, the patients were divided into two groups (i.e. the poor prognosis group and good prognosis group). Statistical analysis was conducted to investigate the clinical significance of dynamic monitoring of CSF and serum Lac, NSE, and BBB index after a severe TBI.

RESULTS

After a severe TBI, the levels of Lac, NSE, and BBB in CSF and serum were significantly higher than those in the normal range. Lac, NSE, and the BBB index did not correlate with ICP (except serum Lac) but had correlations with GCS and post-injury 6 months post-injury (except serum Lac). Moreover, the correlations between Lac, NSE, and BBB index were statistically significant (p < 0.05): CSF Lac and CSF NSE; CSF Lac and serum NSE; Lac and BBB index of CSF; Lac and BBB index of CSF; NSE and CSE of serum; CSF NSE and BBB index; and serum NSE and BBB index. Additionally, serum NSE is correlated with NSE in CSF (p < 0.05).

CONCLUSION

After a severe TBI, dynamic monitoring of CSF and serum Lac, NSE, and BBB index has the potential to assess the condition, predict the prognosis, and have clinical significance.

Potential significance of high-mobility group protein box 1 in cerebrospinal fluid

High-mobility group protein box 1 (HMGB1) is a cytokine with multiple functions (according to its subcellular location) that serves a marker of inflammation. CSF HMGB1 could be the part of pathological mechanisms that underlie the complications associated with CNS diseases. HMGB1 actively or passively released into the CSF is detected in the CSF in many diseases of the central nervous system (CNS) and thus may be useful as a biomarker. Pathological alterations in distant areas were observed due to lesions in a specific region, and the level of HMGB1 in the CSF was found to be elevated. Reducing the HMGB1 level via intraventricular injection of anti-HMGB1 neutralizing antibodies can improve the outcomes of CNS diseases. The results indicated that CSF HMGB1 could serve as a biomarker for predicting disease progression and may also act as a pathogenic factor contributing to pathological alterations in distant areas following focal lesions in the CNS. In this mini-review, the characteristics of HMGB1 and progress in research on CSF HMGB1 as a biomarker of CNS diseases were discussed. CSF HMGB1 is useful not only as a biomarker of CNS diseases but may also be involved in interactions between different brain regions and the spinal cord.

Mitochondria dysregulation contributes to secondary neurodegeneration progression post-contusion injury in human 3D in vitro triculture brain tissue model

Traumatic Brain injury-induced disturbances in mitochondrial fission-and-fusion dynamics have been linked to the onset and propagation of neuroinflammation and neurodegeneration. However, cell-type-specific contributions and crosstalk between neurons, microglia, and astrocytes in mitochondria-driven neurodegeneration after brain injury remain undefined. We developed a human three-dimensional in vitro triculture tissue model of a contusion injury composed of neurons, microglia, and astrocytes and examined the contributions of mitochondrial dysregulation to neuroinflammation and progression of injury-induced neurodegeneration. Pharmacological studies presented here suggest that fragmented mitochondria released by microglia are a key contributor to secondary neuronal damage progression after contusion injury, a pathway that requires astrocyte-microglia crosstalk. Controlling mitochondrial dysfunction thus offers an exciting option for developing therapies for TBI patients.

Correlation Between Clinical Findings at Admission and Glasgow Outcome Scale Score in Children with Traumatic Brain Injury

OBJECTIVE

Traumatic brain injury has different pathophysiology and outcomes in children and adults. This study investigated the relationship between clinical and laboratory findings at admission and Glasgow Outcome Scale (GOS) score in children with traumatic brain injury.

METHODS

This prospective cross-sectional single-center study enrolled 444 children 1-16 years old admitted to the neurosurgery ward from 2016 to 2020. Clinical data and laboratory information were extracted from the records of these patients at admission, and the relationship with GOS score at discharge was investigated.

RESULTS

The 444 patients include 249 (56.08%) boys and 195 (43.92%) girls with a mean age of 7.32 ± 4.4 years. There was no correlation between GOS score and sex (P = 0.12), age (P = 0.16), serum potassium level (P = 0.08), platelet level (P = 0.21), and blood glucose (P = 0.18). There was a significant relationship between GOS score and hypotension (P = 0.03), hyponatremia (P = 0.04), prothrombin time (P = 0.03), partial thromboplastin time (P = 0.03), pupil size (P = 0.02), pupil reaction to light (P = 0.04), and Glasgow Coma Scale score (P = 0.04).

CONCLUSIONS

Clinical and laboratory findings such as hypotension, hyponatremia, prothrombin time, partial thromboplastin time, pupil size, pupil reaction to light, and Glasgow Coma Scale score at admission could affect GOS score at discharge and result in poor outcomes in children with traumatic brain injury.

Nanomaterial-based sandwich-type electrochemical aptasensor platform for sensitive voltammetric determination of leptin

A sandwich-type electrochemical aptasensor was designed for sensitive detection of leptin in biological samples, including human serum and human plasma. The developed aptasensor was produced by electrodeposition of gold nanoparticles on a screen-printed electrode modified with zinc oxide nanoparticles. The synergy effect of zinc oxide and gold nanoparticles improved the electrocatalytic activity of the aptasensor. The obtained high surface area allowed more aptamer molecules to be loaded on the electrode surface. Signal amplification significantly increases the detection sensitivity of a developed biosensor. Although the use of nanomaterials is the most preferred detection tool for this purpose, as an alternative, enzyme-catalyzed signal amplification is widely used in the construction of a biosensor due to its specificity and high catalytic efficiency. Therefore, both nanomaterial-supported and an alkaline phosphatase-based aptasensor design were developed, which can produce in situ electroactive product by enzymatic hydrolysis of the inactive substrate to achieve a higher signal-to-background ratio. Under optimal conditions, the developed aptasensor exhibited a wide linear concentration range from 0.01 pg mL^-1 to 100.0 pg mL^-1 with a detection limit of 0.0035 pg mL^-1. While the developed aptasensor provided excellent selectivity in the presence of some interfering compounds, it possessed outstanding reproducibility and stability. In addition, the developed aptasensor has been applied with good recoveries in the range 96.31 to 108.79% in human serum and plasma samples. In conclusion, all the obtained results showed the feasibility of the developed aptasensor for practical applications.

Association between Day-to-Day Pulsatility Index Change and Neurocognitive Outcomes in Pediatric Traumatic Brain Injury

Traumatic brain injury (TBI) remains a significant cause of morbidity and mortality in children despite advances in prevention and mitigation strategies. Transcranial Doppler (TCD) ultrasound measures cerebral arterial circulation and allows for the calculation of pulsatility indices (PIs), which provides an assessment of cerebral blood flow changes. Yet, the use of PIs in children with TBI is not well understood. In this study, we defined the day-to-day (DTD) PI change of the anterior cerebral circulation and describe its relationship with injury characteristics and neurocognitive outcomes in children with TBI. A prospective observational parent study of 42 children, 2 months to 15 years of age, with mild or moderate-severe TBI who had serial TCDs provided data for this analysis. Both the mean and variation of DTD PI change were evaluated in the context of injury severity, injury sidedness, and neurocognitive outcome. In those with a unilateral injury, a larger mean DTD PI change in both the injured and uninjured side was found in those with a worse Glasgow Outcome Scale-Extended Pediatrics score at discharge. A larger variation in PI was associated with a worse neurocognitive outcome, irrespective of injury severity. Therefore, the mean and variation of DTD PI change may serve as a potential cerebral vascular biomarker of ongoing secondary injury. The use of PI measurements in the monitoring of children with TBI may provide clinicians with new diagnostic and prognostic insights to inform therapeutic interventions and recovery strategies. However, a larger prospective study is needed to confirm these findings and elucidate potential mechanistic links between DTD PI and clinical outcome measures. To our knowledge, this study is the first of its kind to evaluate the use of PI changes in cerebral vasculature in pediatric TBI patients admitted to the hospital.

Fabrication of a label-free electrochemical aptasensor to detect cytochrome c in the early stage of cell apoptosis

A label-free direct electrochemical aptasensor is presented for the identification of cytochrome c (Cyt c) at the nM concentration level. Carbon nanofibers (CNF), as a highly conductive material, were used to modify a glassy carbon electrode (GCE) and thus increase its conductivity. Moreover, to enhance the immobilization of aptamers (Apt) on the electrode surface, graphene oxide functionalized with aspartic acid (GOAsp) was added to the surface. Aspartic acid with countless carboxyl groups (-COOH) on its surface caused more aptamers to be immobilized on the electrode surface. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were used to monitor the step-by-step fabrication of the label-free direct electrochemical aptasensor. The label-free quantification of Cyt c was also done by the direct electron transfer between the Fe(III)/Fe(II)-heme redox-active sites which were selectively bound to the aptamers on the GCE and the surface of the electrode. Under optimum conditions, the peak currents of differential pulse voltammograms at 0.26 V (vs. Ag/AgCl) were used for calibration. The proposed aptasensor performs in a wide dynamic range from 10 nM to 100 µM with a low detection limit of 0.74 nM for cytochrome c. It also has high selectivity as well as acceptable stability. These advantages make the biosensor capable of detecting early-stage apoptotic cells that contribute to early cancer diagnosis.

Biomarkers in Moderate to Severe Pediatric Traumatic Brain Injury: A Review of the Literature

BACKGROUND

Despite decades of research, outcomes in pediatric traumatic brain injury (pTBI) remain highly variable. Brain biofluid-specific biomarkers from pTBI patients may allow us to diagnose and prognosticate earlier and with a greater degree of accuracy than conventional methods. This manuscript reviews the evidence surrounding current brain-specific biomarkers in pTBI and assesses the temporal relationship between the natural history of the traumatic brain injury (TBI) and measured biomarker levels.

METHODS

A literature search was conducted in the Ovid, PubMed, MEDLINE, and Cochrane databases seeking relevant publications. The study selection and screening process were documented in a Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram. Extraction forms included developmental stages of patients, type and biofluid source of biomarkers, brain injury type, and other relevant data.

RESULTS

The search strategy identified 443 articles, of which 150 examining the biomarkers of our interest were included. The references retrieved were examined thoroughly and discussed at length with a pediatric neurocritical care intensivist specializing in pTBI and a Ph.D. scientist with a high degree of involvement in TBI biomarker research, authoring a vast amount of literature in this field.

CONCLUSIONS

TBI biomarkers might serve as valuable tools in the diagnosis and prognosis of pTBI. However, while each biomarker has its advantages, they are not without limitations, and therefore, further research is critical in pTBI biomarkers.

Serum Biomarkers of Regeneration and Plasticity are Associated with Functional Outcome in Pediatric Neurocritical Illness: An Exploratory Study

BACKGROUND/OBJECTIVE

Pediatric neurocritical care survivorship is frequently accompanied by functional impairments. Lack of prognostic biomarkers is a barrier to early identification and management of impairment. We explored the association between blood biomarkers and functional impairment in children with acute acquired brain injury.

METHODS

This study is a secondary analysis of a randomized control trial evaluating early versus usual care rehabilitation in the pediatric intensive care unit (PICU). Forty-four children (17 [39%] female, median age 11 [interquartile range 6-13] years) with acute acquired brain injury admitted to the PICU were studied. A single center obtained serum samples on admission days 0, 1, 3, 5, and the day closest to hospital discharge. Biomarkers relevant to brain injury (neuron specific enolase [NSE], S100b), inflammation (interleukin [IL-6], C-reactive protein), and regeneration (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor [VEGF]) were collected. Biomarkers were analyzed using a Luminex® bioassay. Functional status scale (FSS) scores were abstracted from the medical record. New functional impairment was defined as a (worse) FSS score at hospital discharge compared to pre-PICU (baseline). Individual biomarker fluorescence index (FI) values for each sample collection day were correlated with new functional impairment using Spearman rank correlation coefficient (ρ). Trends in repeated measures of biomarker FI over time were explored graphically, and the association between repeated measures of biomarker FI and new functional impairment was analyzed using covariate adjusted linear mixed-effect models.

RESULTS

Functional impairment was inversely correlated with markers of regeneration and plasticity including BDNF at day 3 (ρ =  - 0.404, p = .015), day 5 (ρ =  - 0.549, p = 0.005) and hospital discharge (ρ =  - 0.420, p = 0.026) and VEGF at day 1 (ρ =  - 0.282, p = 0.008) and hospital discharge (ρ =  - 0.378, p = 0.047), such that lower levels of both markers at each time point were associated with greater impairment. Similarly, repeated measures of BDNF and VEGF were inversely correlated with new functional impairment (B =  - 0.001, p = 0.001 and B =  - 0.001, p = 0.003, respectively). NSE, a biomarker of acute brain injury, showed a positive correlation between day 0 levels and new functional impairment (ρ = 0.320, p = 0.044).

CONCLUSIONS

Blood-based biomarkers of regeneration and plasticity may hold prognostic utility for functional impairment among pediatric patients with neurocritical illness and warrant further investigation.

Novel severe traumatic brain injury blood outcome biomarkers identified with proximity extension assay

OBJECTIVES

Severe traumatic brain injury (sTBI) patients suffer high mortality. Accurate prognostic biomarkers have not been identified. In this exploratory study, we performed targeted proteomics on plasma obtained from sTBI patients to identify potential outcome biomarkers.

METHODS

Blood sample was collected from patients admitted to the ICU suffering a sTBI, using standardized clinical and computerized tomography (CT) imaging criteria. Age- and sex-matched healthy control subjects and sTBI patients were enrolled. Targeted proteomics was performed on plasma with proximity extension assays (1,161 proteins).

RESULTS

Cohorts were well-balanced for age and sex. The majority of sTBI patients were injured in motor vehicle collisions and the most frequent head CT finding was subarachnoid hemorrhage. Mortality rate for sTBI patients was 40%. Feature selection identified the top performing 15 proteins for identifying sTBI patients from healthy control subjects with a classification accuracy of 100%. The sTBI proteome was dominated by markers of vascular pathology, immunity/inflammation, cell survival and macrophage/microglia activation. Receiver operating characteristic (ROC) curve analyses demonstrated areas-under-the-curves (AUC) for identifying sTBI that ranged from 0.870-1.000 (p≤0.005). When mortality was used as outcome, ROC curve analyses identified the top 3 proteins as Willebrand factor (vWF), Wnt inhibitory factor-1 (WIF-1), and colony stimulating factor-1 (CSF-1). Combining vWF with either WIF-1 or CSF-1 resulted in excellent mortality prediction with AUC of 1.000 for both combinations (p=0.011).

CONCLUSIONS

Targeted proteomics with feature classification and selection distinguished sTBI patients from matched healthy control subjects. Two protein combinations were identified that accurately predicted sTBI patient mortality. Our exploratory findings require confirmation in larger sTBI patient populations.

Penetrating Traumatic Brain Injury Triggers Dysregulation of Cathepsin B Protein Levels Independent of Cysteine Protease Activity in Brain and Cerebral Spinal Fluid

Cathepsin B (CatB), a lysosomal cysteine protease, is important to brain function and may have dual utility as a peripheral biomarker of moderate-severe traumatic brain injury (TBI). The present study determined levels of pro- and mature (mat) CatB protein as well as cysteine protease activity within the frontal cortex (FC; proximal injury site), hippocampus (HC; distal injury site), and cerebral spinal fluid (CSF) collected 1-7 days after craniotomy and penetrating ballistic-like brain injury (PBBI) in rats. Values were compared with naïve controls. Further, the utility of CatB protein as a translational biomarker was determined in CSF derived from patients with severe TBI. Craniotomy increased matCatB levels in the FC and HC, and led to elevation of HC activity at day 7. PBBI caused an even greater elevation in matCatB within the FC and HC within 3-7 days. After PBBI, cysteine protease activity peaked at 3 days in the FC and was elevated at 1 day and 7 days, but not 3 days, in the HC. In rat CSF, proCatB, matCatB, and cysteine protease activity peaked at 3 days after craniotomy and PBBI. Addition of CA-074, a CatB-specific inhibitor, confirmed that protease activity was due to active matCatB in rat brain tissues and CSF at all time-points. In patients, CatB protein was detectable from 6 h through 10 days after TBI. Notably, CatB levels were significantly higher in CSF collected within 3 days after TBI compared with non-TBI controls. Collectively, this work indicates that CatB and its cysteine protease activity may serve as collective molecular signatures of TBI progression that differentially vary within both proximal and distal brain regions. CatB and its protease activity may have utility as a surrogate, translational biomarker of acute-subacute TBI.

Serum Neuron-specific Enolase and S100 Calcium-binding Protein B in Pediatric Diabetic Ketoacidosis

Objective

Neuron-specific enolase (NSE) and S100 calcium-binding protein B (S100B) are markers of different neurological disorders. The aim was to investigate the relationship between NSE and S100B serum concentrations and the severity of diabetic ketoacidosis (DKA) in diabetic children.

Methods

Eighty children with DKA, 40 with type 1 diabetes mellitus (T1DM) without DKA and 40 healthy controls were enrolled. Severity of DKA was assessed according to blood pH and bicarbonate concentration. Serum NSE and S100B were measured in all participants. In the DKA group serum NSE and S100B were measured at three time points, at admission and at 12 hours and 24 hours after starting treatment.

Results

Children with DKA showed significantly higher serum levels of NSE at all time points compared to children with T1DM without DKA and controls (p<0.01), while serum S100B concentrations did not differ between the three cohorts. Children with T1DM but without DKA also had significantly higher serum levels of NSE (p<0.01) compared to healthy controls. Patients with low Glasgow Coma Scale score (GCSS) and those with moderate and severe DKA had significantly higher levels of NSE at all time points (p<0.01 for each) compared to patients with normal GCSS and those with mild DKA. No significant differences were found in serum S100B levels according to the severity of DKA and GCS (p>0.05). Younger age, lower GCSS, higher glucose and HbA1c, lower pH and lower serum bicarbonate were the risk factors associated with elevated NSE.

Conclusion

Serum NSE is elevated in all patients with type 1 DM and, in patients with DKA, correlates with severity of DKA. However, serum S100B concentration did not differ between T1DM with or without DKA and healthy controls.

Best Practices for Obtaining Genomic Consent in Pediatric Traumatic Brain Injury Research

BACKGROUND

Precision health relies on large sample sizes to ensure adequate power, generalizability, and replicability; however, a critical first step to any study is the successful recruitment of participants.

OBJECTIVES

This study seeks to explore how the enrollment strategies used in a parent study contributed to the high consent rates, establish current best practices that can be used in future studies, and identify additional factors that contribute to consent into pediatric traumatic brain injury biobanks.

METHODS

Retrospective secondary analysis of data from a parent study with high consent rates was examined to explore factors affecting consent into biobanking studies.

RESULTS

Of the 76 subjects who were approached, met the eligibility criteria, and reviewed the consent form, only 16 (21.1%) declined to participate. The consented group (n = 60) represents 64.5% of those who met the eligibility criteria upon initial screening (n = 93) and 78.9% of those with confirmed eligibility (n = 76). Analysis of screening data suggested there were no major barriers to consenting individuals into this pediatric traumatic brain injury biobank.

DISCUSSION

There were no demographic or research-related characteristics that significantly explained enrollment. Ethically, to obtain true informed consent, parents need to understand only their child's diagnosis, prognosis, and medical care, as well as the purpose of the proposed research and its risks and benefits. Researchers need to implement best practices, including a comprehensive review of census data to identify eligible participants to approach, a prescreening protocol, and effective consenting process to obtain informed consent so that precision care initiatives can be pursued.

Factors Predicting Outcomes in Surgically Treated Pediatric Traumatic Brain Injury

Introduction

Traumatic brain injury (TBI) is a common presentation to the pediatric emergency department. Understanding factors that predict outcomes will be useful in clinical decision-making and prognostication. The objective of this study was to identify important clinical parameters predictive of outcomes in pediatric TBI patients who underwent surgery.

Materials and Methods

This retrospective study included 43 pediatric TBI patients who underwent surgery from January 2011 to January 2017. Clinical parameters, including presenting signs and symptoms, mechanism of injury, intracranial pressure (ICP), need for inotropes, and computed tomography findings were collected. Outcomes were assessed using the Glasgow outcome score (GOS) based on the latest follow-up. Outcomes were divided into favorable (GOS 4-5) and unfavorable (GOS 1-3).

Results

Surgery was performed in 43 patients. The mean age was 9.6 ± 4.9. The mean follow-up period was 31 weeks. Thirty (70%) patients had favorable outcome and 13 (30%) had unfavorable outcome. On univariate analysis, mechanism of injury, vomiting, Glasgow coma scale score, pupil size and reactivity, hypotension, inotropic use, need for blood transfusion, and raised ICP (all P < 0.005) were significantly associated with outcomes. On step-wise logistic regression, only raised ICP (odds ratio [OR] = 35.6, P = 0.008) and hypotension (OR = 26.1, P = 0.01) were found to be statistically significant.

Conclusion

The present study suggests that the majority of pediatric TBI patients who required neurosurgical intervention have favorable outcomes. Closer attention should be paid to raised ICP and hypotension as they were strong predictors of unfavorable outcomes. These findings also help manage expectations of patients' family and clinicians.

Collection and Analyses of Cerebrospinal Fluid for Pediatric Translational Research

Cerebrospinal fluid sample collection and analysis is imperative to better elucidate central nervous system injury and disease in children. Sample collection methods are varied and carry with them certain ethical and biologic considerations, complications, and contraindications. Establishing best practices for sample collection, processing, storage, and transport will ensure optimal sample quality. Cerebrospinal fluid samples can be affected by a number of factors including subject age, sampling method, sampling location, volume extracted, fraction, blood contamination, storage methods, and freeze-thaw cycles. Indicators of sample quality can be assessed by matrix-associated laser desorption/ionization time-of-flight mass spectrometry and include cystatin C fragments, oxidized proteins, prostaglandin D synthase, and evidence of blood contamination. Precise documentation of sample collection processes and the establishment of meticulous handling procedures are essential for the creation of clinically relevant biospecimen repositories. In this review we discuss the ethical considerations and best practices for cerebrospinal fluid collection, as well as the influence of preanalytical factors on cerebrospinal fluid analyses. Cerebrospinal fluid biomarkers in highly researched pediatric diseases or disorders are discussed.

Post-mortem biochemistry of NSE and S100B: A supplemental tool for detecting a lethal traumatic brain injury?

PURPOSE

Traumatic brain injury (TBI) is a very common entity that leads to numerous fatalities all over the world. Therefore, forensic pathologists are in desperate need of supplemental methodological tools for the diagnosis of TBI in everyday practice besides the standard autopsy. The present study determined post-mortem neuron specific enolase (NSE) and S100 calcium-binding protein B (S100B) levels as biological markers of an underlying TBI in autopsy cases.

METHODS

Paired serum and CSF samples of 92 fatalities were collected throughout routine autopsies. Afterwards, the marker levels were assessed using commercially available immunoassays (ECLIA, Roche Diagnostics). For statistical analysis, we compared the TBI cases to three control groups (sudden natural death by acute myocardial infarction, traumatic death without impact on the head, cerebral hypoxia). Moreover, the TBI cases were subdivided according to their survival time of the trauma. Brain specimens have been collected and stained immunohistochemically against the aforementioned proteins to illustrate their typical cellular staining patterns with an underlying TBI compared to non-TBI fatalities.

PRINCIPAL RESULTS

CSF NSE and S100B levels were elevated after TBI compared to all control groups (p < 0.001). Although this finding can already be investigated among the TBI cases dying immediately subsequent to the trauma, the marker levels in CSF increase with longer survival times until a peak level within the first three days after trauma. There is a strong correlation between both marker levels in CSF (r = 0.67). The presence or absence of cerebral tissue contusion following the initial trauma does not seem to affect the CSF levels of both proteins (p > 0.05). Post-mortem serum levels of both proteins were not elevated in TBI cases compared to controls (p > 0.05). Former elaborated cut-off values in CSF were confirmed and were only exceeded when a TBI survival time of at least 30 min was reached.

MAJOR CONCLUSIONS

The present results report that post-mortem NSE and S100B CSF levels are significantly elevated subsequent to a fatal TBI.

Traumatic brain injury: classification, models, and markers

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Due to its high incidence rate and often long-term sequelae, TBI contributes significantly to increasing costs of health care expenditures annually. Unfortunately, advances in the field have been stifled by patient and injury heterogeneity that pose a major challenge in TBI prevention, diagnosis, and treatment. In this review, we briefly discuss the causes of TBI, followed by its prevalence, classification, and pathophysiology. The current imaging detection methods and animal models used to study brain injury are examined. We discuss the potential use of molecular markers in detecting and monitoring the progression of TBI, with particular emphasis on microRNAs as a novel class of molecular modulators of injury and its repair in the neural tissue.

Relationship of calcitonin gene-related peptide with disease progression and prognosis of patients with severe traumatic brain injury

Calcitonin gene-related peptide (CGRP) has been implicated in multiple functions across many bioprocesses; however, whether CGRP is associated with severe traumatic brain injury (TBI) remains poorly understood. In this study, 96 adult patients with TBI (enrolled from September 2015 to December 2016) were divided into a mild/moderate TBI group (36 males and 25 females, aged 38 ± 13 years) and severe TBI group (22 males and 13 females, aged 38 ± 11 years) according to Glasgow Coma Scale scores. In addition, 25 healthy individuals were selected as controls (15 males and 10 females, aged 39 ± 13 years). Radioimmunoassay was used to detect serum levels of CGRP and endothelin-1 at admission and at 12, 24, 48, 72 hours, and 7 days after admission. CGRP levels were remarkably lower, but endothelin-1 levels were obviously higher in the severe TBI group compared with mild/moderate TBI and control groups. Levels of CGRP were remarkably lower, but endothelin-1 levels were obviously higher in deceased patients compared with patients who survived. Survival analysis and logistic regression showed that both CGRP and endothelin-1 levels were associated with patient mortality, with each serving as an independent risk factor for 6-month mortality of severe TBI patients. Moreover, TBI patients with lower serum CGRP levels had a higher risk of death. Thus, our retrospective analysis demonstrates the potential utility of CGRP as a new biomarker, monitoring method, and therapeutic target for TBI.

Meta-analysis of neuron specific enolase in predicting pediatric brain injury outcomes

A reliable biomarker has not been identified to predict the outcome of traumatic brain injury (TBI) in children. Therefore, the present systematic review and meta-analysis aimed to assess the association between neuron specific enolase (NSE) and traumatic brain injury (TBI) in children. Two independent reviewers searched electronic databases of EMBASE, Cochrane library, Medline and Scopus and then they summarized the results and did a quality control check. At the end, standardized mean difference (SMD) with 95 % confidence interval (CI) and performance of NSE were assessed. 10 studies were included in the present meta-analysis. Average serum (SMD=1.3; 95 % CI: 0.5 to 2.1; p=0.001) and CSF levels (SMD=2.45; 95 % CI: 1.04 to 3.8; p<0.0001) of NSE biomarker were significantly higher in children with TBI with unfavorable outcome compared with other children. Serum NSE had an area under the curve, sensitivity and specificity of 0.75 (95 % CI: 0.72 to 0.79), 0.74 (95 % CI: 0.64 to 0.82) and 0.69 (95 % CI: 0.59 to 0.77), respectively in prediction outcome of TBI. Positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio of serum NSE were 2.4 (95 % CI: 1.7 to 3.3), 0.38 (95 % CI: 0.26 to 0.55) and 6.0 (95 % CI: 3.0 to 12.0), respectively. The results show that the performance of NSE is in a moderate level in prediction of unfavorable outcome in children with TBI. However, data in this aspect is not sufficient and more studies are needed.

Translating biomarkers from research to clinical use in pediatric neurocritical care: focus on traumatic brain injury and cardiac arrest

PURPOSE OF REVIEW

Traumatic brain injury (TBI) and cardiac arrest are important causes of morbidity and mortality in children. Improved diagnosis and outcome prognostication using validated biomarkers could allow clinicians to better tailor therapies for optimal efficacy.

RECENT FINDINGS

Contemporary investigation has yielded plentiful biomarker candidates of central nervous system (CNS) injury, including macromolecules, genetic, inflammatory, oxidative, and metabolic biomarkers. Biomarkers have yet to be validated and translated into bedside point-of-care or cost-effective and efficient laboratory tests. Validation testing should consider developmental status, injury mechanism, and time trajectory with patient-centered outcomes.

SUMMARY

Recent investigation of biomarkers of CNS injury may soon improve diagnosis, management, and prognostication in children with traumatic brain injury and cardiac arrest.

Past, Present, and Future of Traumatic Brain Injury Research

Traumatic brain injury (TBI) is the greatest cause of death and severe disability in young adults; its incidence is increasing in the elderly and in the developing world. Outcome from severe TBI has improved dramatically as a result of advancements in trauma systems and supportive critical care, however we remain without a therapeutic which acts directly to attenuate brain injury. Recognition of secondary injury and its molecular mediators has raised hopes for such targeted treatments. Unfortunately, over 30 late-phase clinical trials investigating promising agents have failed to translate a therapeutic for clinical use. Numerous explanations for this failure have been postulated and are reviewed here. With this historical context we review ongoing research and anticipated future trends which are armed with lessons from past trials, new scientific advances, as well as improved research infrastructure and funding. There is great hope that these new efforts will finally lead to an effective therapeutic for TBI as well as better clinical management strategies.

Chapter 6 state of the science of pediatric traumatic brain injury: biomarkers and gene association studies

OBJECTIVES

Our objective is to review the most widely used biomarkers and gene studies reported in pediatric traumatic brain injury (TBI) literature, to describe their findings, and to discuss the discoveries and gaps that advance the understanding of brain injury and its associated outcomes. Ultimately, we aim to inform the science for future research priorities.

DATA SOURCES

We searched PubMed, MEDLINE, CINAHL, and the Cochrane Database of Systematic Reviews for published English language studies conducted in the last 10 years to identify reviews and completed studies of biomarkers and gene associations in pediatric TBI. Of the 131 biomarker articles, only 16 were specific to pediatric TBI patients, whereas of the gene association studies in children with TBI, only four were included in this review.

CONCLUSION

Biomarker and gene attributes are grossly understudied in pediatric TBI in comparison to adults. Although recent advances recognize the importance of biomarkers in the study of brain injury, the limited number of studies and genomic associations in the injured brain has shown the need for common data elements, larger sample sizes, heterogeneity, and common collection methods that allow for greater understanding of the injured pediatric brain. By building on to the consortium of interprofessional scientists, continued research priorities would lead to improved outcome prediction and treatment strategies for children who experience a TBI.

IMPLICATIONS FOR NURSING RESEARCH

Understanding recent advances in biomarker and genomic studies in pediatric TBI is important because these advances may guide future research, collaborations, and interventions. It is also important to ensure that nursing is a part of this evolving science to promote improved outcomes in children with TBIs.

Are UCH-L1 and GFAP promising biomarkers for children with mild traumatic brain injury?

OBJECTIVES

To compare serum biomarker levels between children with mild traumatic brain injury (mTBI) and orthopaedic injury (OI), acutely following injury. Secondarily, to explore the association between biomarker levels and symptom burden over 1 month post-injury.

METHODS

This was a prospective cohort study of children aged 11-16 years who presented to the emergency department within 6 hours of sustaining mTBI or isolated extremity OI. Serum was drawn at the time of study enrollment and levels of ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) and glial fibrillary acid protein (GFAP) were analysed. Symptom burden was assessed by the Post-Concussion Symptom Scale (PCSS) acutely following injury and at three subsequent time points over 1 month.

RESULTS

Twenty-five children with mTBI and 20 children with OI were enrolled. The average age for the overall cohort was 13 (± 1.6) years and the majority were male and injured playing sports. GFAP levels and PCSS scores were significantly higher acutely following mTBI vs OI (p < 0.01). There was not a significant group difference in UCH-L1 levels. Neither GFAP nor UCH-L1 were predictive of PCSS scores over the 1month post-injury.

CONCLUSIONS

GFAP may be a promising diagnostic tool for children with mTBI. Additional approaches are needed to predict symptom severity and persistence.

Low serum ficolin-3 levels are associated with severity and poor outcome in traumatic brain injury

Background

Ficolin-mediated activation of the lectin pathway of complement contributes to the complement-independent inflammatory processes of traumatic brain injury. Lower serum ficolin-3 levels have been demonstrated to be highly associated with unfavorable outcome after ischemic stroke. This prospective observatory study was designed to investigate the relationships between serum ficolin-3 levels and injury severity and clinical outcomes after severe traumatic brain injury.

Methods

Serum ficolin-3 levels of 128 patients and 128 healthy controls were measured by sandwich immunoassays. An unfavorable outcome was defined as Glasgow Outcome Scale score of 1–3. Study endpoints included mortality at 1 week and 6 months and unfavorable outcome at 6 months after head trauma. Injury severity was assessed by Glasgow Coma Scale score. Multivariate logistic models were structured to evaluate the relationships between serum ficolin-3 levels and study endpoints and injury severity.

Results

Compared with the healthy controls, serum ficolin-3 levels on admission were statistically decreased in patients with severe traumatic brain injury. Serum ficolin-3 levels were independently correlated with Glasgow Coma Scale scores. Ficolin-3 was also identified as an independent prognostic predictor for 1-week mortality, 6-month mortality, and 6-month unfavorable outcome. Under receiver operating characteristics curves, ficolin-3 has similar prognostic predictive values for all study endpoints compared with Glasgow Coma Scale scores.

Conclusions

It was proposed that lower serum ficolin-3 levels, correlated with injury severity, had the potential to be the useful, complementary tool to predict short- or long-term clinical outcomes after severe traumatic brain injury.

Umbilical cord blood concentrations of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) in neonates developing hypoxic-ischemic encephalopathy

OBJECTIVE

To compare ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) concentrations in umbilical cord blood of neonates who develop Sarnat stage II-III hypoxic-ischemic encephalopathy (HIE) to healthy controls, and to relate the concentrations to the severity of neurology and long-time outcomes.

MATERIAL AND METHODS

Cord sera of 15 neonates with HIE II-III and 31 matched controls were analyzed for UCH-L1 and GFAP. Comparisons were performed for cord artery pH, amplitude-integrated electroencephalography (aEEG), stage of HIE, and death or sequelae up to an age of 6 years. Parametric and non-parametric statistics were used with a two-sided p < 0.05 considered significant.

RESULTS

Among controls no associations between biomarker concentrations and gestational age, birthweight, length of storage of cord sera and degree of hemolysis were found. No significant differences in biomarker concentrations were found between HIE neonates and controls, and no differences were found with regard to HIE stage, cord acidemia, severity of aEEG changes, or persistent sequelae or death.

CONCLUSIONS

No differences in cord blood UCH-L1 and GFAP concentrations were found between HIE neonates and controls, and no associations were found between the biomarker concentrations and the severity of disease, or whether the condition developed into a permanent or fatal injury.

Biomarkers and genetics of brain injury risk in diabetic ketoacidosis: A pilot study

Diabetic ketoacidosis (DKA) is the primary cause of death for children with diabetes, especially when complicated by cerebral edema. Central nervous system (CNS) involvement is common, however the mechanism of, and predictors of CNS dysfunction/injury are largely unknown. In this observational pilot study, blood was collected from pediatric DKA patients at three time points (consent, 12 hr and 24 hr after beginning treatment), to test genetic markers, ribonucleic acid expression and plasma biomarkers reflecting inflammation (tumor necrosis factor-alpha [TNF-α], interleukin-6 [IL-6]) and cerebral dysfunction and/or possible injury (S100β, glial fibrillary acidic protein [GFAP]). Thirty patients were enrolled in the study. The average age was 11.3 yr, 73% were new onset diabetes and 53% were female. Forty percent exhibited abnormal mentation (Glasgow Coma Scale <15), consistent with CNS dysfunction. IL-6 and TNF-α were elevated in plasma, suggesting systemic inflammation. GFAP was measurable in 45% of patients and correlated positively with GCS. Only two patients had detectable levels of S100β. In conclusion, children with DKA often present with evidence of acute neurologic dysfunction or injury. We have demonstrated the feasibility of exploring genetic and biochemical markers of potential importance in the pathophysiology of CNS dysfunction and/or possible injury in DKA. We have identified IL-6, TNF-α and GFAP as potentially important markers for further exploration. A larger, follow-up study will help to better understand the extent and type of CNS injury in DKA as well as the mechanism underlying this dysfunction/injury.

Serum ubiquitin C-terminal hydrolase L1 as a biomarker for traumatic brain injury: a systematic review and meta-analysis

OBJECTIVE

Serum ubiquitin C-terminal hydrolase L1 (UCH-L1) has been proposed as a biomarker of traumatic brain injury (TBI). However, previous studies on levels of UCH-L1 in serum remain inconsistent. This systematic review and meta-analysis were conducted on observational studies that reported the association between serum UCH-L1 levels and TBI.

METHODS

Studies were identified by searching PubMed and ISI Web of Science up to February 2015. For the continuous outcomes, we calculated the weighted mean difference and 95% confidence interval. The statistical analysis was performed by RevMan 5.1 and Stata 12 software. Only case-control studies were included if they had data on serum UCH-L1 levels in TBI patients and healthy controls. Funnel plot and Egger's regression test were applied to assess the potential publication bias.

RESULTS

Of the 145 selected studies, 11 observational studies (including 9 case-control and 2 case-crossover studies) met the selection criteria, containing a total of 1138 TBI cases and 1373 controls. Finally, 5 case-control studies (including 673 TBI and 1004 controls) were eligible for the present meta-analysis. The results of our study showed that there was a significant increase in serum UCH-L1 levels in patients with TBI compared to controls (weighted mean difference, 0.96; 95% confidence interval, 0.31-1.61; P = .004).

CONCLUSION

In conclusion, TBI cases had higher serum UCH-L1 concentrations than matched controls. This reinforces the conceptualization of UCH-L1 as a potential biomarker of TBI.

Prognostic value of copeptin in patients with acute stroke

CONTEXT

There is a need to improve stroke care through the prompt identification of stroke patients at increased risk of an adverse outcome.

OBJECTIVE

To evaluate the prognostic value of copeptin in patients with stroke.

METHODS

We systematically searched PubMed and Embase for relevant studies. Poor outcome and mortality were analyzed.

RESULTS

Twelve studies, containing 2682 patients, were included. Pooled analysis showed that copeptin is an independent prognostic marker of poor outcome after acute stroke and there is a borderline effect of copeptin in predicting mortality after acute stroke.

CONCLUSIONS

Copeptin is an independent predictor of poor outcome and mortality for patients with acute stroke.

Bench-to-Bedside and Bedside Back to the Bench; Seeking a Better Understanding of the Acute Pathophysiological Process in Severe Traumatic Brain Injury

Despite substantial investments, traumatic brain injury (TBI) remains one of the major disorders that lack specific pharmacotherapy. To a substantial degree, this situation is due to lack of understanding of the pathophysiological process of the disease. Experimental TBI research offers controlled, rapid, and cost-effective means to identify the pathophysiology but translating experimental findings into clinical practice can be further improved by using the same or similar outcome measures and clinically relevant time points. The pathophysiology during the acute phase of severe TBI is especially poorly understood. In this Mini review, I discuss some of the incongruences between current clinical practices and needs versus information provided by experimental TBI research as well as the benefits of designing animal experiments with translation into clinical practice in mind.

Proteomics: in pursuit of effective traumatic brain injury therapeutics

Effective traumatic brain injury (TBI) therapeutics remains stubbornly elusive. Efforts in the field have been challenged by the heterogeneity of clinical TBI, with greater complexity among underlying molecular phenotypes than initially conceived. Future research must confront the multitude of factors comprising this heterogeneity, representing a big data challenge befitting the coming informatics age. Proteomics is poised to serve a central role in prescriptive therapeutic development because it offers an efficient endpoint within which to assess post-TBI biochemistry. We examine rationale for multifactor TBI proteomic studies and the particular importance of temporal profiling in defining biochemical sequences and guiding therapeutic development. Finally, we offer perspective on repurposing biofluid proteomics to develop theragnostic assays with which to prescribe, monitor and assess pharmaceutics for improved translation and outcome for patients with TBI.

Serum UCH-L1 as a Novel Biomarker to Predict Neuronal Apoptosis Following Deep Hypothermic Circulatory Arrest

BACKGROUND

Deep hypothermic circulatory arrest (DHCA) has been used in cardiac surgery involving infant complex congenital heart disease and aortic dissection. DHCA carries a risk of neuronal apoptotic death in brain. Serum ubiquitin C-terminal hydrolase L1 (UCH-L1) level is elevated in a number of neurological diseases involving neuron injury and death. We studied the hypothesis that UCH-L1 may be a potential biomarker for DHCA-induced ischemic neuronal apoptosis.

METHODS

Anesthetized piglets were used to perform cardiopulmonary bypass (CPB). DHCA was induced for 1 hour followed by CPB rewarming. Blood samples were collected and serum UCH-L1 levels were measured. Neuron apoptosis and Bax and Bcl-2 proteins in hippocampus were examined. The relationship between neuron apoptosis and UCH-L1 level was determined by receiver operating characteristics (ROC) curves and correlation analysis.

RESULTS

DHCA resulted in marked neuronal apoptosis, significant increase in Bax:Bcl-2 ratio in hippocampus and UCH-L1 level elevations in serum (all P<0.05). Positive correlation was obtained between serum UCH-L1 level and the severity of neuron apoptosis (r= 0.78, P<0.01). By ROC, the area under the curve were 0.88 (95% CI: 0.74-0.99; P<0.01), 0.81 (95% CI: 0.81-0.96; P<0.05), 0.71 (95% CI: 0.47-0.92; P=0.11) for UCH-L1, Bax/Bcl-2 ratio and Bax, respectively. Using a cut-off point of 0.25, the UCH-L1 predicted neuronal apoptosis with a sensitivity of 85% and specificity of 57%.

CONCLUSION

Serum UCH-L1, as an easy and quick measurable biomarker, can predict neural apoptosis induced by DHCA. The elevation in UCH-L1 concentration is consistent with the severity of neural apoptosis following DHCA.