The potential for bio-mediators and biomarkers in pediatric traumatic brain injury and neurocritical care

Serum neuron-specific enolase can predict the severity and outcome of anti-N-methyl-D-aspartate receptor encephalitis

BACKGROUND

Little is known about the association between serum neuron-specific enolase (NSE) concentration and anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. This study aims to investigate if serum NSE concentration is related to the clinical features of anti-NMDAR encephalitis.

METHODS

Serum NSE levels were detected in 58 anti-NMDAR encephalitis cases, 58 matched healthy controls and 58 matched disease controls. Demographic features, clinical symptoms, cerebrospinal fluid parameters and brain MRI indexes of the cases were evaluated.

RESULTS

Serum NSE concentrations were significant higher in case group than those in healthy controls and disease controls (both p < 0.001). Serum NSE concentrations in patients with mRS≥3 one year after onset were obviously higher than in those with mRS<3 (p < 0.001). Patients with status epilepticus or central hypoventilation had higher serum NSE levels than those without (p = 0.003 and p = 0.006). Serum NSE concentrations in cases with brain lesions or brain atrophy were significant higher than in those without (p = 0.001 and p < 0.001, respectively). Serum NSE concentrations were found to be significant higher in cases with limited response to treatment compared to those with favourable therapy outcomes (p < 0.001). Spearman's correlation analysis showed a significant positive association between serum NSE concentration and mRS score at the most critical time (max mRS) (r = 0.575, p < 0.001) and one year after onset (r = 0.705, p < 0.001). Cox regression results reflected that high serum NSE level was an independent predictor of poor prognosis in anti-NMDAR encephalitis group (p = 0.001), and the ROC curve threshold value was 15.72 ng/ml.

CONCLUSIONS

Serum NSE concentrations in anti-NMDAR encephalitis cases are higher than those in controls. It can be used to predict the brain damage degree and prognosis of anti-NMDAR encephalitis cases.

Evaluation of neurovascular coupling during neuroprotective therapies: A single site HEAL ancillary study

BACKGROUND

There is a critical need for development of physiological biomarkers in infants with birth asphyxia to identify the physiologic response to therapies in real time. This is an ancillary single site study of the High-Dose Erythropoietin for Asphyxia and Encephalopathy (Wu et al., 2022 [1]) to measure neurovascular coupling (NVC) non-invasively during an ongoing blinded randomized trial.

METHODS

Neonates who randomized in the HEAL enrolled at a single-center Level III Neonatal Intensive Care Unit were recruited between 2017 and 2019. Neurodevelopmental impairment was blinded and defined as any of the following: cognitive score <90 on Bayley Scales of Infant Toddler Development, third edition (BSID-III), Gross Motor Function Classification Score (GMFCS) ≥1.

RESULTS

All twenty-seven neonates enrolled in HEAL were recruited and 3 died before complete recording. The rank-based analysis of covariance models demonstrated lack of difference in NVC between the two groups (Epo versus Placebo) that was consistent with the observed lack of effect on neurodevelopmental outcomes.

CONCLUSION

We demonstrate no difference in neurovascular coupling after Epo administration. These findings are consistent with overall negative trial results. Physiological biomarkers can help elucidate mechanisms of neuroprotective therapies in real time in future trials.

Abusive Head Trauma Animal Models: Focus on Biomarkers

Abusive head trauma (AHT) is a serious traumatic brain injury and the leading cause of death in children younger than 2 years. The development of experimental animal models to simulate clinical AHT cases is challenging. Several animal models have been designed to mimic the pathophysiological and behavioral changes in pediatric AHT, ranging from lissencephalic rodents to gyrencephalic piglets, lambs, and non-human primates. These models can provide helpful information for AHT, but many studies utilizing them lack consistent and rigorous characterization of brain changes and have low reproducibility of the inflicted trauma. Clinical translatability of animal models is also limited due to significant structural differences between developing infant human brains and the brains of animals, and an insufficient ability to mimic the effects of long-term degenerative diseases and to model how secondary injuries impact the development of the brain in children. Nevertheless, animal models can provide clues on biochemical effectors that mediate secondary brain injury after AHT including neuroinflammation, excitotoxicity, reactive oxygen toxicity, axonal damage, and neuronal death. They also allow for investigation of the interdependency of injured neurons and analysis of the cell types involved in neuronal degeneration and malfunction. This review first focuses on the clinical challenges in diagnosing AHT and describes various biomarkers in clinical AHT cases. Then typical preclinical biomarkers such as microglia and astrocytes, reactive oxygen species, and activated N-methyl-D-aspartate receptors in AHT are described, and the value and limitations of animal models in preclinical drug discovery for AHT are discussed.

Pediatric Traumatic Brain Injury: An Update on Preclinical Models, Clinical Biomarkers, and the Implications of Cerebrovascular Dysfunction

Traumatic brain injury (TBI) is a leading cause of pediatric morbidity and mortality. Recent studies suggest that children and adolescents have worse post-TBI outcomes and take longer to recover than adults. However, the pathophysiology and progression of TBI in the pediatric population are studied to a far lesser extent compared to the adult population. Common causes of TBI in children are falls, sports/recreation-related injuries, non-accidental trauma, and motor vehicle-related injuries. A fundamental understanding of TBI pathophysiology is crucial in preventing long-term brain injury sequelae. Animal models of TBI have played an essential role in addressing the knowledge gaps relating to pTBI pathophysiology. Moreover, a better understanding of clinical biomarkers is crucial to diagnose pTBI and accurately predict long-term outcomes. This review examines the current preclinical models of pTBI, the implications of pTBI on the brain’s vasculature, and clinical pTBI biomarkers. Finally, we conclude the review by speculating on the emerging role of the gut-brain axis in pTBI pathophysiology.

Unravelling neuroinflammation in abusive head trauma with radiotracer imaging

Abusive head trauma (AHT) is a leading cause of mortality and morbidity in child abuse, with a mortality rate of approximately 25%. In survivors, the prognosis remains dismal, with high prevalence of cerebral palsy, epilepsy and neuropsychiatric disorders. Early and accurate diagnosis of AHT is challenging, both clinically and radiologically, with up to one-third of cases missed on initial examination. Moreover, most of the management in AHT is supportive, reflective of the lack of clear understanding of specific pathogenic mechanisms underlying secondary insult, with approaches targeted toward decreasing intracranial hypertension and reducing cerebral metabolism, cell death and excitotoxicity. Multiple studies have elucidated the role of pro- and anti-inflammatory cytokines and chemokines with upregulation/recruitment of microglia/macrophages, oligodendrocytes and astrocytes in severe traumatic brain injury (TBI). In addition, recent studies in animal models of AHT have demonstrated significant upregulation of microglia, with a potential role of inflammatory cascade contributing to secondary insult. Despite the histological and biochemical evidence, there is a significant dearth of specific imaging approaches to identify this neuroinflammation in AHT. The primary motivation for development of such imaging approaches stems from the need to therapeutically target neuroinflammation and establish its utility in monitoring and prognostication. In the present paper, we discuss the available data suggesting the potential role of neuroinflammation in AHT and role of radiotracer imaging in aiding diagnosis and patient management.

Brain Injury in Extracorporeal Membrane Oxygenation: A Multidisciplinary Approach

Extracorporeal membrane oxygenation (ECMO) represents an established technique to provide temporary cardiac and/or pulmonary support. ECMO, in veno-venous, veno-arterial or in extracorporeal carbon dioxide removal modality, is associated with a high rate of brain injuries. These complications have been reported in 7 to 15% of adults and 20% of neonates, and are associated with poor survival. Thromboembolic events, loss of cerebral autoregulation, alteration of the blood-brain barrier, and hemorrhage related to anticoagulation represent the main causes of severe brain injury during ECMO. The most frequent forms of acute neurological injuries in ECMO patients are intracranial hemorrhage (2-21%), ischemic stroke (2-10%), seizures (2-6%), and hypoxic-ischemic brain injury; brain death may also occur in this population. Other frequent complications are infarction (1-8%) and cerebral edema (2-10%), as well as neuropsychological and psychiatric sequelae, including posttraumatic stress disorder.

Blood Biomarkers for Detection of Brain Injury in COVID-19 Patients

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus attacks multiple organs of coronavirus disease 2019 (COVID-19) patients, including the brain. There are worldwide descriptions of neurological deficits in COVID-19 patients. Central nervous system (CNS) symptoms can be present early in the course of the disease. As many as 55% of hospitalized COVID-19 patients have been reported to have neurological disturbances three months after infection by SARS-CoV-2. The mutability of the SARS-COV-2 virus and its potential to directly affect the CNS highlight the urgency of developing technology to diagnose, manage, and treat brain injury in COVID-19 patients. The pathobiology of CNS infection by SARS-CoV-2 and the associated neurological sequelae of this infection remain poorly understood. In this review, we outline the rationale for the use of blood biomarkers (BBs) for diagnosis of brain injury in COVID-19 patients, the research needed to incorporate their use into clinical practice, and the improvements in patient management and outcomes that can result. BBs of brain injury could potentially provide tools for detection of brain injury in COVID-19 patients. Elevations of BBs have been reported in cerebrospinal fluid (CSF) and blood of COVID-19 patients. BB proteins have been analyzed in CSF to detect CNS involvement in patients with infectious diseases, including human immunodeficiency virus and tuberculous meningitis. BBs are approved by the U.S. Food and Drug Administration for diagnosis of mild versus moderate traumatic brain injury and have identified brain injury after stroke, cardiac arrest, hypoxia, and epilepsy. BBs, integrated with other diagnostic tools, could enhance understanding of viral mechanisms of brain injury, predict severity of neurological deficits, guide triage of patients and assignment to appropriate medical pathways, and assess efficacy of therapeutic interventions in COVID-19 patients.

Patterns of Osteopontin Expression in Abusive Head Trauma Compared with Other Causes of Pediatric Traumatic Brain Injury

OBJECTIVE

To examine levels of plasma osteopontin (OPN), a recently described neuroinflammatory biomarker, in children with abusive head trauma (AHT) compared with children with other types of traumatic brain injury (TBI).

STUDY DESIGN

The study cohort comprised children aged <4 years diagnosed with TBI and seen in the intensive care unit in a tertiary children's hospital. Patients were classified as having confirmed or suspected AHT or TBI by other mechanisms (eg, motor vehicle accidents), as identified by a Child Protection Team clinician. Serial blood samples were collected at admission and at 24, 48, and 72 hours after admission. Levels of OPN were compared across groups.

RESULTS

Of 77 patients identified, 24 had confirmed AHT, 12 had suspected AHT, and 41 had TBI. There were no differences in the Glasgow Coma Scale score between the patients with confirmed AHT and those with suspected AHT and those with TBI (median score, 4.5 vs 4 and 7; P = .39). At admission to the emergency department, OPN levels were significantly higher in children with confirmed AHT compared with the other 2 groups (mean confirmed AHT, 471.5 ng/mL; median suspected AHT, 322.3 ng/mL; mean TBI, 278.0 ng/mL; P = .03). Furthermore, the adjusted mean trajectory levels of OPN were significantly higher in the confirmed AHT group compared with the other 2 groups across all subsequent time points (P = <.01).

CONCLUSIONS

OPN is significantly elevated in children with confirmed AHT compared with those with suspected AHT and those with other types of TBI. OPN expression may help identify children with suspected AHT to aid resource stratification and triage of appropriate interventions for children who are potential victims of abuse.

Tau Is Elevated in Pediatric Patients on Extracorporeal Membrane Oxygenation

Neurologic injury is a known and feared complication of extracorporeal membrane oxygenation (ECMO). Neurologic biomarkers may have a role in assisting in early identification of such. Axonal biomarker tau has not been investigated in the pediatric ECMO population. The objective of this study is to evaluate plasma levels of tau in pediatric patients supported with ECMO. Eighteen patients requiring ECMO support in a quaternary pediatric intensive care unit at a university-affiliated children's hospital from October 2015 to February 2017 were enrolled. Patients undergoing extracorporeal cardiopulmonary resuscitation or recent history of bypass were excluded. Plasma tau was measured using enzyme-linked immunosorbent assay. Neuroimaging was reviewed for acute neurologic injury, and tau levels were analyzed to assess for correlation. Tau was significantly higher in ECMO patients than in control subjects. Sixty-one percent of subjects had evidence of acute brain injury on neuroimaging, but tau level did not correlate with injury. Subjects with multifocal injury all experienced infarction and had significantly higher tau levels on ECMO day 3 than patients with isolated injury. In addition, peak tau levels of neuro-injured subjects were compared with controls and noninjured ECMO subjects using receiver operating curve analysis. This study demonstrates preliminary evidence of axonal injury in pediatric ECMO patients.

Neurological Monitoring and Complications of Pediatric Extracorporeal Membrane Oxygenation Support

Extracorporeal membrane oxygenation is extracorporeal life support for life-threatening cardiopulmonary failure. Since its introduction, the use of extracorporeal membrane oxygenation has expanded to patients with more complex comorbidities without change in patient mortality rates. Although many patients survive, significant neurological complications like seizures, ischemic strokes, and intracranial hemorrhage can occur during extracorporeal membrane oxygenation care. The risks of these complications often add to the complexity of decision-making surrounding extracorporeal membrane oxygenation support. In this review, we discuss the pathophysiology and incidence of neurological complications in children supported on extracorporeal membrane oxygenation, factors influencing the incidence of these complications, commonly used neurological monitoring modalities, and outcomes for this complex patient population. We discuss the current literature on the use of electroencephalography for both seizure detection and monitoring of background electroencephalographic changes, in addition to the use of less commonly used imaging modalities like transcranial Doppler. We summarize the knowledge gaps and the lack of clinical consensus guidelines for managing these potentially life-changing neurological complications. Finally, we discuss future work to further understand the pathophysiology of extracorporeal membrane oxygenation-related neurological complications.

Retinal and visual function in infants with non-accidental trauma and retinal hemorrhages

PURPOSE

To investigate retinal function and visual outcomes in infants with retinal hemorrhages due to non-accidental trauma (NAT).

METHODS

This is a retrospective review of full-field or multifocal electroretinogram (ERG) recordings, visual acuity in log minimum angle of resolution (logMAR), clinical status, and neuroimaging. Multifocal ERGs from the central 40° were compared to corresponding fundus imaging. Visual acuity was measured by Teller cards at follow-up. ERGs were compared to controls recorded under anesthesia.

RESULTS

Sixteen children met inclusion criteria (14 recorded during the acute phase and 2 during long-term follow-up). During the acute phase, ERGs (n = 4 full field; n = 10 multifocal ERG) showed abnormal amplitude, latency, or both in at least one eye. Ten subjects had significantly reduced responses in both eyes, 3 of which had an ERG dominated by a negative waveform (absent b-wave or P1). The remaining six subjects had responses in one eye that were near normal (≥ 50% of controls). ERGs were sometimes abnormal in local areas without hemorrhage. ERGs could be preserved in local areas adjacent to traumatic retinoschisis. Two subjects with reduced visual acuity had belated ERGs: One had an abnormal macular ERG and the other had a normal macular ERG implying cortical visual impairment. At follow-up, 10 of 14 subjects had significant visual acuity loss (≥ 0.7 age-corrected logMAR); four subjects had mild vision loss (≤ 0.5 age-corrected logMAR). Visual acuity outcome was not reliably associated with the fundus appearance in the acute phase. All subjects with a negative ERG waveform had severe vision loss on follow-up.

CONCLUSIONS

Retinal dysfunction was common during the acute phase of NAT. A near normal appearing fundus did not imply normal retinal function, and ERG abnormality did not always predict a poor visual acuity outcome. However, a negative ERG waveform was associated severe visual acuity loss. Potential artifacts of retinal hemorrhages and anesthesia could not fully account for multifocal ERG abnormalities. Retinal function can be preserved in areas adjacent to traumatic retinoschisis.

Adiponectin attenuates neuronal apoptosis induced by hypoxia-ischemia via the activation of AdipoR1/APPL1/LKB1/AMPK pathway in neonatal rats

Adiponectin is an important adipocyte-derived plasma protein that has beneficial effects on cardio- and cerebrovascular diseases. A low level of plasma Adiponectin is associated with increased mortality post ischemic stroke; however, little is known about the causal role of Adiponectin as well as its molecular mechanisms in neonatal hypoxia ischemia (HI). In the present study, ten-day-old rat pups were subjected to right common carotid artery ligation followed by 2.5 h hypoxia. Recombinant human Adiponectin (rh-Adiponectin) was administered intranasally 1 h post HI. Adiponectin Receptor 1 (AdipoR1) siRNA, APPL1 siRNA, LKB1 siRNA were administered through intracerebroventricular injection 48 h before HI. Brain infarct area measurement, neurological function test, western blot, Fluoro Jade C (FJC), TUNEL, and immunofluorescence staining were conducted. Results revealed that endogenous Adiponectin, AdipoR1 and APPL1 were increased in a time dependent manner after HI. Administration of rh-Adiponectin reduced brain infarct area, neuronal apoptosis, brain atrophy and improved neurological function at 24 h and 4 weeks post HI. Furthermore, rh-Adiponectin treatment increased Adiponectin, AdipoR1, APPL1, cytosolic LKB1, p-AMPK expression levels and thereby attenuated apoptosis as shown by the decreased expression of the pro-apoptotic marker, Cleaved Caspase 3 (C-Cas3), as well as the number of FJC and TUNEL positively stained neurons. AdipoR1, APPL1 and LKB1 siRNAs abolished the anti-apoptotic effects of rh-Adiponectin at 24 h after HI. Collectively, the data provided evidence that intranasal administration of rh-Adiponectin attenuated neuronal apoptosis at least in part via activating AdipoR1/APPL1/LKB1/AMPK signaling pathway. Adiponectin could represent a therapeutic target for treatment of neonatal hypoxic ischemic encephalopathy.

Serum neuron specific enolase is increased in pediatric acute encephalitis syndrome

PURPOSE

This study aimed to investigate whether serum neuron-specific enolase (NSE) was expressed in acute encephalitis syndrome (AES) that causes neuronal damage in children.

METHODS

This prospective observational study was conducted in the pediatric neurology ward of Soetomo Hospital. Cases of AES with ages ranging from 1 month to 12 years were included. Cases that were categorized as simple and complex febrile seizures constituted the non-AES group. Blood was collected for the measurement of NSE within 24 hours of hemodynamic stabilization. The median NSE values of both groups were compared by using the Mann-Whitney U test. All statistical analyses were performed with SPSS version 12 for Windows.

RESULTS

In the study period, 30 patients were enrolled. Glasgow Coma Scale mostly decreased in the AES group by about 40% in the level ≤8. All patients in the AES group suffered from status epilepticus and 46.67% of them had body temperature >40℃. Most of the cases in the AES group had longer duration of stay in the hospital. The median serum NSE level in the AES group was 157.86 ng/mL, and this value was significantly higher than that of the non-AES group (10.96 ng/mL; P<0.05).

CONCLUSION

AES cases showed higher levels of serum NSE. These results indicate that serum NSE is a good indicator of neuronal brain injury.

Brain metabolism and severe pediatric traumatic brain injury

Age-dependent changes in brain metabolism may influence the response to and tolerance of secondary insults, potentially affecting outcomes. More complete characterization of brain metabolism across the clinical trajectory of severe pediatric TBI is needed to improve our ability to measure and better mitigate the impact of secondary insults. Better management of secondary insults will impact clinical care and the probability of success of future neuroprotective clinical trials. Improved bedside monitoring and imaging technologies will be required to achieve these goals. Effective and sustained integration of brain metabolism information into the pediatric critical care setting will be equally challenging and important.

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.

Differential expression of microRNAs in the brains of mice subjected to increasing grade of mild traumatic brain injury

OBJECTIVE

To investigate the effect of heterogeneity in mTBI on miRNA expression in mouse brain and to identify molecular pathways targeted by the modulated miRNAs.

METHODS

A weight drop device was used to induce four increasing grades of mTBI. MiRNA expression was evaluated using TaqMan rodent miRNA arrays. Bioinformatics analysis was done using the DIANA miRPath tool and Ingenuity Pathway Analysis software. Histology of brain sections was evaluated using H&E staining.

RESULTS

No histologic lesions were observed in the brains of injured mice; however, significant modulation in miRNA expression profile was observed. Global miRNA profiling indicated a trend of decrease in the number of modulated miRNAs from 24 hours to day 7 post-injury, except for the most severe grade of mTBI. Canonical pathways like calcium signalling, synaptic pathways and axon guidance pathway were the major targets of the modulated miRNAs. Network correlation analyses indicated an interaction between the modulated miRNAs and putative protein biomarkers of TBI.

CONCLUSIONS

The data demonstrated that varying intensities of mTBI induced a differential miRNA expression profile in the brain post-injury. Pathways such as calcium and synaptic signalling were major targets of modulated miRNAs and may play a role in the pathophysiology of mTBI.

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.

Exploratory study of serum ubiquitin carboxyl-terminal esterase L1 and glial fibrillary acidic protein for outcome prognostication after pediatric cardiac arrest

INTRODUCTION

Brain injury is the leading cause of morbidity and death following pediatric cardiac arrest. Serum biomarkers of brain injury may assist in outcome prognostication. The objectives of this study were to evaluate the properties of serum ubiquitin carboxyl-terminal esterase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) to classify outcome in pediatric cardiac arrest.

METHODS

Single center prospective study. Serum biomarkers were measured at 2 time points during the initial 72 h in children after cardiac arrest (n=19) and once in healthy children (controls, n=43). We recorded demographics and details of the cardiac arrest and resuscitation. We determined the associations between serum biomarker concentrations and Pediatric Cerebral Performance Category (PCPC) at 6 months (favorable (PCPC 1-3) or unfavorable (PCPC 4-6)).

RESULTS

The initial assessment (time point 1) occurred at a median (IQR) of 10.5 (5.5-17.0)h and the second assessment (time point 2) at 59.0 (54.5-65.0)h post-cardiac arrest. Serum UCH-L1 was higher among children following cardiac arrest than among controls at both time points (p<0.05). Serum GFAP in subjects with unfavorable outcome was higher at time point 2 than in controls (p<0.05). Serum UCH-L1 at time point 1 (AUC 0.782) and both UCH-L1 and GFAP at time point 2 had good classification accuracy for outcome (AUC 0.822 and 0.796), p<0.05 for all.

CONCLUSION

Preliminary data suggest that serum UCH-L1 and GFAP may be of use to prognosticate outcome after pediatric cardiac arrest at clinically-relevant time points and should be validated prospectively.

Diagnosis and management of paediatric concussion

Heightened recognition of concussions and concerns about their sequelae in children has become an increasing community and public health concern. Biomarkers and clinical tests are being explored, but the diagnosis of concussion in the emergency department continues to be based on clinical signs and symptoms. While the majority of children go on to recover from post-concussive symptoms within 2 weeks, it is unclear which patients with concussion will go on to develop short- or long-term sequelae. A number of more or less evidence-based guidelines have become available which seek to guide clinicians on how to manage children post-concussion. In general, care after the emergency department is focused on reducing the risk of re-injury and rest until cerebral recovery with a graduated return to school and then play.

Approach to Modeling, Therapy Evaluation, Drug Selection, and Biomarker Assessments for a Multicenter Pre-Clinical Drug Screening Consortium for Acute Therapies in Severe Traumatic Brain Injury: Operation Brain Trauma Therapy

Traumatic brain injury (TBI) was the signature injury in both the Iraq and Afghan wars and the magnitude of its importance in the civilian setting is finally being recognized. Given the scope of the problem, new therapies are needed across the continuum of care. Few therapies have been shown to be successful. In severe TBI, current guidelines-based acute therapies are focused on the reduction of intracranial hypertension and optimization of cerebral perfusion. One factor considered important to the failure of drug development and translation in TBI relates to the recognition that TBI is extremely heterogeneous and presents with multiple phenotypes even within the category of severe injury. To address this possibility and attempt to bring the most promising therapies to clinical trials, we developed Operation Brain Trauma Therapy (OBTT), a multicenter, pre-clinical drug screening consortium for acute therapies in severe TBI. OBTT was developed to include a spectrum of established TBI models at experienced centers and assess the effect of promising therapies on both conventional outcomes and serum biomarker levels. In this review, we outline the approach to TBI modeling, evaluation of therapies, drug selection, and biomarker assessments for OBTT, and provide a framework for reports in this issue on the first five therapies evaluated by the consortium.

Increased cerebrospinal fluid cleaved tau protein (C-tau) levels suggest axonal damage in pediatric patients with brain tumors

OBJECTIVE

This study aims to determine if cerebrospinal fluid/serum cleaved tau protein and CSF 9-hydroxyoctadecadienoic acid levels, reflecting potential biomarkers of overall neuronal injury and lipid peroxidation, respectively, are elevated in brain tumor patients compared with controls.

DESIGN

This article is a prospective clinical observational study.

SETTING

This study is conducted at a tertiary-care children's hospital.

PATIENTS

Our participants are children younger than or equal to 18 years of age undergoing brain tumor surgery.

MEASUREMENTS AND MAIN RESULTS

During the study period, 26 consecutive patients newly diagnosed with brain tumors who met the inclusion criteria were prospectively enrolled. Baseline cerebrospinal fluid analysis of cleaved tau and 9-hydroxyoctadecadienoic acid were measured in 15 patients. Cerebrospinal fluid cleaved tau and 9-hydroxyoctadecadienoic acid levels were measured in 22 patients for post-surgery days 1 and 3. Serum cleaved tau levels were measured for 20 and 18 patients for post-surgery days 1 and 3, respectively. The presence of a brain tumor significantly increased the baseline cerebrospinal fluid cleaved tau levels but did not affect cerebrospinal fluid 9-hydroxyoctadecadienoic acid levels. Similarly, there was a significant increase in post-surgery day 1 cerebrospinal fluid cleaved tau levels from baseline (p = 0.01) and a trend toward significant decrease in post-surgery day 3 cerebrospinal fluid cleaved tau from day 1 (p = 0.07). 9-Hydroxyoctadecadienoic acid concentrations remained relatively constant over time with no differences noted between the control and brain tumor patients. There was a trend towards a significant association between cerebrospinal fluid cleaved tau levels and duration of symptoms (p = 0.07).

CONCLUSIONS

Cerebrospinal fluid cleaved tau levels in children with newly diagnosed brain tumors exhibit markedly elevated cerebrospinal fluid cleaved tau levels, suggesting axonal damage. This axonal injury does not seem to correlate with lipid peroxidation at least when as assessed by cerebrospinal fluid 9-hydroxyoctadecadienoic acid levels. There was no association found between the biomarkers and multiple independent variables obtained at pre- and post-tumor resection.

Cellular and molecular mechanisms of radiation-induced brain injury: can peripheral markers be detected?

Investigation of the mechanisms of radiation-induced brain injury is a relevant fundamental objective of radiobiology and neuroradiology. Damage to the healthy brain tissue is the key factor limiting the application of radiation therapy in patients with nervous systems neoplasms. Furthermore, postradiation brain injury can be clinically indiscernible from continued tumor growth and requires differential diagnosis. Thus, there exists high demand for biomarkers of radiation effects on the brain in neurosurgery and radiobiology. These markers could be used for better understanding and quantifying the effects of ionizing radiation on brain tissues, as well as for elaborating personalized therapy. Despite the high demand, biomarkers of radiation-induced brain injury have not been identified thus far. The cellular and molecular mechanisms of the effect of ionizing radiation on the brain were analyzed in this review in order to identify potential biomarkers of radiation-induced injury to nervous tissue.

Abusive head trauma: past, present, and future

Abusive head trauma has a robust and interesting scientific history. Recently, the American Academy of Pediatrics has endorsed a change in terminology to a term that is more general in describing the vast array of abusive mechanisms that can result in pediatric head injury. Simply defined, abusive head trauma is "child physical abuse that results in injury to the head or brain." Abusive head trauma is a relatively common cause of childhood neurotrauma, with an estimated incidence of 16 to 33 cases per 100,000 children per year in the first 2 years of life. Clinical findings are variable; AHT should be considered in all children with neurologic signs and symptoms, especially if no or only mild trauma is described. Subdural and retinal hemorrhages are the most common findings. The current best evidence-based literature has identified some features--apnea and severe retinal hemorrhages--that reliably discriminate abusive from accidental injury. Longitudinal studies of outcomes in abusive head trauma patients demonstrate that approximately one-third of the children are severely disabled, one third of them are moderately disabled, and one third have no or only mild symptoms. Abusive head trauma cases are complex cases that require a rigorous, multidisciplinary team approach. The clinician can establish this diagnosis with confidence if he/she maintains a high index of suspicion for the diagnosis, has knowledge of the signs, symptoms, and risk factors of abusive head trauma, and reasonably excludes other etiologies on the differential diagnosis.

Microwave & Magnetic (M2) Proteomics of a Mouse Model of Mild Traumatic Brain Injury

Short-term increases in oxidative stress and decreases in motor function, including debilitating effects on balance and motor control, can occur following primary mild traumatic brain injuries (mTBI). However, the long-term effects on motor unit impairment and integrity as well as the molecular mechanisms underlying secondary injuries are poorly understood. We hypothesized that changes in central nervous system-specific protein (CSP) expression might correlate to these long-term effects. To test our hypothesis, we longitudinally assessed a closed-skull mTBI mouse model, vs. sham control, at 1, 7, 30, and 120 days post-injury. Motor impairment was determined by rotarod and grip strength performance measures, while motor unit integrity was determined using electromyography. Relative protein expression was determined by microwave & magnetic (M²) proteomics of ipsilateral brain tissue, as previously described. Isoprostane measurements were performed to confirm a primary oxidative stress response. Decoding the relative expression of 476 ± 56 top-ranked proteins for each specimen revealed statistically significant changes in the expression of two well-known CSPs at 1, 7 and 30 days post-injury: P < 0.001 for myelin basic protein (MBP) and P < 0.05 for myelin associated glycoprotein (MAG). This was confirmed by Western blot. Moreover, MAG, αII-spectrin (SPNA2) and neurofilament light (NEFL) expression at 30 days post-injury were directly related to grip strength (P < 0.05). While higher-powered studies of larger cohorts merit further investigation, this study supports the proof-of-concept that M² proteomics is a rapid method to quantify putative protein biomarkers and therapeutic targets of mTBI and suggests the feasibility of CSP expression correlations to long-term effects on motor impairment.

Perinatal biomarkers in prematurity: early identification of neurologic injury

Over the past few decades, biomarkers have become increasingly utilized as non-invasive tools in the early diagnosis and management of various clinical conditions. In perinatal medicine, the improved survival of extremely premature infants who are at high risk for adverse neurologic outcomes has increased the demand for the discovery of biomarkers in detecting and predicting the prognosis of infants with neonatal brain injury. By enabling the clinician to recognize potential brain damage early, biomarkers could allow clinicians to intervene at the early stages of disease, and to monitor the efficacy of those interventions. This review will first examine the potential perinatal biomarkers for neurologic complications of prematurity, specifically, intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL) and posthemorrhagic hydrocephalus (PHH). It will also evaluate knowledge gained from animal models regarding the pathogenesis of perinatal brain injury in prematurity.

Post-acute brain injury urinary signature: a new resource for molecular diagnostics

Heterogeneity within brain injury presents a challenge to the development of informative molecular diagnostics. Recent studies show progress, particularly in cerebrospinal fluid, with biomarker assays targeting one or a few structural proteins. Protein-based assays in peripheral fluids, however, have been more challenging to develop, in part because of restricted and intermittent barrier access. Further, a greater number of molecular variables may be required to inform on patient status given the multi-factorial nature of brain injury. Presented is an alternative approach profiling peripheral fluid for a class of small metabolic by-products rendered by ongoing brain pathobiology. Urine specimens were collected for head trauma subjects upon admission to acute brain injury rehabilitation and non-traumatized matched controls. An innovative data-independent mass spectrometry approach was employed for reproducible molecular quantification across osmolarity-normalized samples. The postacute human traumatic brain injury urinary signature encompassed 2476 discriminant variables reproducibly measured in specimens for subject classification. Multiple subprofiles were then discerned in correlation with injury severity per the Glasgow Comma Scale and behavioral and neurocognitive function per the Patient Competency Rating Scale and Frontal Systems Behavioral Scale. Identified peptide constituents were enriched for outgrowth and guidance, extracellular matrix, and post-synaptic density proteins, which were reflective of ongoing post-acute neuroplastic processes demonstrating pathobiological relevance. Taken together, these findings support further development of diagnostics based on brain injury urinary signatures using either combinatorial quantitative models or pattern-recognition methods. Particularly, these findings espouse assay development to address unmet diagnostic and theragnostic needs in brain injury rehabilitative medicine.

Detection of alpha II-spectrin breakdown products in the serum of neonates with congenital heart disease*

OBJECTIVES

To determine if alpha II-spectrin breakdown products can be detected in the serum of neonates with congenital heart disease in the perioperative period.

DESIGN

Prospective observational cohort study.

SETTING

Pediatric cardiac ICU in an urban tertiary care academic center.

PATIENTS

Neonates with congenital heart disease undergoing surgical repair or palliation.

INTERVENTIONS

Serial blood sampling for measurement of 120 and 150 kDa spectrin breakdown products.

MEASUREMENTS AND MAIN RESULTS

Fourteen neonates with congenital heart disease undergoing cardiac surgery were evaluated. Nine infants underwent open-heart surgery and five underwent closed-heart surgery. Serum spectrin breakdown products were measured with sandwich enzyme-linked immunosorbent assay preoperatively and then 6, 24, 48, 72, and 96 hours following surgery. Brain imaging was obtained as part of routine clinical care in 12 patients preoperatively and six patients postoperatively. Six patients had normal preoperative imaging (three closed-heart surgery and three open-heart surgery), whereas six had evidence of neurologic injury prior to surgery (one closed-heart surgery and five open-heart surgery). Only one patient had a postoperative imaging study that lacked injury. All others demonstrated infarction or hemorrhage. Spectrin breakdown product 120 kDa significantly increased 24 hours after open-heart surgery compared to preoperative values and time-matched closed-heart surgery levels. Spectrin breakdown product 150 kDa significantly increased 6 hours after open-heart surgery compared to preoperative values. There was no significant change in spectrin breakdown products following closed-heart surgery. Peak spectrin breakdown products significantly increased following open-heart surgery compared to closed-heart surgery.

CONCLUSIONS

Spectrin breakdown products can be detected in the serum of neonates with congenital heart disease in the perioperative period and levels increased to a greater degree in infants following open-heart surgery. These findings suggest that, in future work, serum spectrin breakdown products may potentially be developed as biomarkers for brain necrosis and apoptosis in infants with congenital heart disease.