S100-B protein as a screening tool for the early assessment of minor head injury

Minor head injury in anticoagulated patients: performance of biomarkers S100B, NSE, GFAP, UCH-L1 and Alinity TBI in the detection of intracranial injury. A prospective observational study

OBJECTIVES

Data in literature indicate that in patients suffering a minor head injury (MHI), biomarkers serum levels could be effective to predict the absence of intracranial injury (ICI) on head CT scan. Use of these biomarkers in case of patients taking oral anticoagulants who experience MHI is very limited. We investigated biomarkers as predictors of ICI in anticoagulated patients managed in an ED.

METHODS

We conducted a single-cohort, prospective, observational study in an ED. Our structured clinical pathway included a first head CT scan, 24 h observation and a second CT scan. The outcome was delayed ICI (dICI), defined as ICI on the second CT scan after a first negative CT scan. We assessed the sensitivity (SE), specificity (SP), negative predictive value (NNV) and positive predictive value (PPV) of the biomarkers S100B, NSE, GFAP, UCH-L1 and Alinity TBI in order to identify dICI.

RESULTS

Our study population was of 234 patients with a negative first CT scan who underwent a second CT scan. The rate of dICI was 4.7 %. The NPV for the detection of dICI were respectively (IC 95 %): S100B 92.7 % (86.0-96.8 %,); ubiquitin C-terminal hydrolase-L1 (UCH-L1) 91.8 % (83.8-96.6 %); glial fibrillary protein (GFP) 100 % (83.2-100 %); TBI 100 % (66.4-100 %). The AUC for the detection of dICI was 0.407 for S100B, 0.563 for neuron-specific enolase (NSE), 0.510 for UCH-L1 and 0.720 for glial fibrillary acidic protein (GFAP), respectively.

CONCLUSIONS

The NPV of the analyzed biomarkers were high and they potentially could limit the number of head CT scan for detecting dICI in anticoagulated patients suffering MHI. GFAP and Alinity TBI seem to be effective to rule out a dCI, but future trials are needed.

Brain Injury Biomarkers and Applications in Neurological Diseases

ABSTRACT

Neurological diseases are a major health concern, and brain injury is a typical pathological process in various neurological disorders. Different biomarkers in the blood or the cerebrospinal fluid are associated with specific physiological and pathological processes. They are vital in identifying, diagnosing, and treating brain injuries. In this review, we described biomarkers for neuronal cell body injury (neuron-specific enolase, ubiquitin C-terminal hydrolase-L1, αII-spectrin), axonal injury (neurofilament proteins, tau), astrocyte injury (S100β, glial fibrillary acidic protein), demyelination (myelin basic protein), autoantibodies, and other emerging biomarkers (extracellular vesicles, microRNAs). We aimed to summarize the applications of these biomarkers and their related interests and limits in the diagnosis and prognosis for neurological diseases, including traumatic brain injury, status epilepticus, stroke, Alzheimer's disease, and infection. In addition, a reasonable outlook for brain injury biomarkers as ideal detection tools for neurological diseases is presented.

Development of a time-resolved immunochromatographic test strip for rapid and quantitative determination of GFAP in serum

Glial fibrillary acidic protein (GFAP) in serum has been shown as a biomarker of traumatic brain injury (TBI) which is a significant global public health concern. Accurate and rapid detection of serum GFAP is critical for TBI diagnosis. In this study, a time-resolved fluorescence immunochromatographic test strip (TRFIS) was proposed for the quantitative detection of serum GFAP. This TRFIS possessed excellent linearity ranging from 0.05 to 2.5 ng/mL for the detection of serum GFAP and displayed good linearity (Y = 598723X + 797198, R2 = 0.99), with the lowest detection limit of 16 pg/mL. This TRFIS allowed for quantitative detection of serum GFAP within 15 min and showed high specificity. The intra-batch coefficient of variation (CV) and the inter-batch CV were both < 4.0%. Additionally, this TRFIS was applied to detect GFAP in the serum samples from healthy donors and patients with cerebral hemorrhage, and the results of TRFIS could efficiently discern the patients with cerebral hemorrhage from the healthy donors. Our developed TRFIS has the characteristics of high sensitivity, high accuracy, and a wide linear range and is suitable for rapid and quantitative determination of serum GFAP on-site.

Protein-S-100-beta is increased in patients with decompensated cirrhosis admitted to ICU

Background

Hepatic encephalopathy (HE) is highly prevalent in patients with liver diseases. The pathophysiology of HE is centered on the synergic role of hyperammonemia and systemic inflammation. However, some data suggest altered functioning of the blood-brain barrier (BBB). Assessing BBB function is challenging in clinical practice and at the bedside. Protein-S-100 Beta (PS100-Beta) could be a useful peripheral marker of BBB permeability in HE. This study aimed to assess plasmatic PS100-Beta levels in a prospective cohort of patients admitted to the intensive care unit (ICU) with decompensated cirrhosis with and without overt HE.

Methods

We retrospectively evaluated a prospective cohort of cirrhotic patients admitted to the ICU from October 2013 to September 2015 that had an available plasmatic PS100-Beta measurement. Patients with previous neurological impairment or limitation of intensive or resuscitative measures were excluded. Overt HE was defined as West-Haven grades 2 to 4. The patients were compared to a control cohort of outpatient clinic cirrhotic and non-cirrhotic patients explored for isolated elevation of liver enzymes. After ICU discharge, the patients were followed for at least 3 months for the occurrence of overt HE. Adverse outcomes (liver transplantation or death) were collected. The ability of PS100-Beta - in combination with other factors - to predict overt HE was evaluated in a multivariate analysis using logistic regression. Likelihood ratios were used to determine the effects and calculate odds ratios (OR). Survival analysis was performed by using the Kaplan-Meier method and survival between groups was compared using a Log-rank test.

Results

A total of 194 ICU patients and 207 outpatients were included in the study. Increased levels of plasmatic PS100-Beta were detected in the ICU decompensated cirrhotic patients compared with the outpatients ([0.15±0.01] mg/L vs. [0.08±0] mg/L, P <0.001). ICU patients with overt HE had higher levels of PS100-Beta ([0.19±0.03] mg/L) compared with the ICU patients without overt HE ([0.13±0.01] mg/L) (P=0.003). PS100-Beta levels did not differ in outpatients with F 0-3 compared to F 4 fibrosis (P=0.670). PS100-Beta values were correlated with Child-Pugh score (P <0.001), Model for End-Stage Liver Disease (MELD) score (P=0.004), C-reactive protein (P <0.001), ammonemia (P <0.001), and chronic liver failure consortium (CLIF-C) organ failure (P <0.001) and CLIF-C acute-on-chronic (P=0.038) scores, but not with leukocytes (P=0.053), procalcitonin (PCT) (P=0.107), or the lymphocyte-to-neutrophil ratio in ICU patients (P=0.522). In a multivariate model including age, ammonemia, PS100-Beta, PCT, MELD, presence of transjugular portosystemic shunt, and sodium level, the diagnostic performance was 0.765 for the diagnosis of overt HE. Patients with a PS100-Beta level <0.12 mg/L had a better overall survival (P=0.019) and a better survival without liver transplantation (P=0.013).

Conclusions

Serum levels of PS100-Beta are elevated in ICU patients with decompensated cirrhosis, and even more so in those displaying overt HE, and the levels are correlated with outcome. This suggests an increase in the permeability of the BBB in these patients.

Clinical value of S100B in detecting intracranial injury in elderly patients with mild traumatic brain injury

OBJECTIVE

The biomarker S100B is a sensitive biomarker to detect traumatic intracranial injury in patients mild traumatic brain injury (mTBI). Higher blood values of S100B, resulting in lower specificity and decreased head computed tomography (CT) reduction has been regarded as one of shortcomings in patients over 65 years of age. The purpose of this study was to assess the accuracy of plasma S100B to detect intracranial injury in elderly patients with mTBI.

METHODS

A posthoc analysis was performed of a larger prospective cohort study. Previous recorded patient variables and plasma values of S100B from patients with mTBI who presented to the Emergency Department (ED) within 6 h of injury, underwent a head CT and had a blood sample drawn as part of their routine clinical care, were partitioned at 65 years of age. Sensitivity, specificity, negative predictive value, and positive predictive value of plasma S100B for predicting traumatic intracranial lesions on head CT, with a cut-off set at 0.105 μg/L, were calculated. Results were compared with data from an additional systematic review on the accuracy of S100B to detect intracranial injury in elderly patients with mTBI.

RESULTS

Data of 240 patients (48.4 %) of 65 years or older were analyzed. Sensitivity and NPV of S100B were 89 % and 86 % respectively, which is lower than among younger patients (both 97 %). The specificity decreased stepwise with older age: 22 %, 18 %, and 5 % for the age groups 65-74, 75-84, and ≥ 85 years old, respectively. The meta-analysis comprised 4 studies and the current study with data from 2166 patients. Pooled data estimated the sensitivity of s100B as 97.4 % (95 % CI 83.3-100 %) and specificity as 17.3 % (95 % CI 9.5-29.3 %) to detect intracranial injury in elderly patients with mTBI.

CONCLUSION

The biomarker S100B at the routine threshold has a limited clinical value in the management of elderly mTBI patients mainly due to a poor specificity leading to only a small decrease in head CTs. Alternate cut-off values and combining several plasma biomarkers with clinical variables may be useful strategies to increase the accuracy of S100B in (subgroups of) elderly mTBI patients.

Screening Performance of S100 Calcium-Binding Protein B, Glial Fibrillary Acidic Protein, and Ubiquitin C-Terminal Hydrolase L1 for Intracranial Injury Within Six Hours of Injury and Beyond

The Scandinavian NeuroTrauma Committee (SNC) guidelines recommend S100 calcium-binding protein B (S100B) as a screening tool for early detection of Traumatic brain injury (TBI) in patients presenting with an initial Glasgow Coma Scale (GCS) of 14-15. The objective of the current study was to compare S100B's diagnostic performance within the recommended 6-h window after injury, compared with glial fibrillary acidic protein (GFAP) and UCH-L1. The secondary outcome of interest was the ability of these biomarkers in detecting traumatic intracranial pathology beyond the 6-h mark. The Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) core database (2014-2017) was queried for data pertaining to all TBI patients with an initial GCS of 14-15 who had a blood sample taken within 6 h of injury in which the levels of S100B, GFAP, and UCH-L1 were measured. As a subgroup analysis, data involving patients with blood samples taken within 6-9 h and 9-12 h were analyzed separately for diagnostic ability. The diagnostic ability of these biomarkers for detecting any intracranial injury was evaluated based on the area under the receiver operating characteristic curve (AUC). Each biomarker's sensitivity, specificity, and accuracy were also reported at the cutoff that maximized Youden's index. A total of 531 TBI patients with GCS 14-15 on admission had a blood sample taken within 6 h, of whom 24.9% (n = 132) had radiologically confirmed intracranial injury. The AUCs of GFAP (0.86, 95% confidence interval [CI]: 0.82-0.90) and UCH-L1 (0.81, 95% CI: 0.76-0.85) were statistically significantly higher than that of S100B (0.74, 95% CI: 0.69-0.79) during this time. There was no statistically significant difference in the predictive ability of S100B when sampled within 6 h, 6-9 h, and 9-12 h of injury, as the p values were >0.05 when comparing the AUCs. Overlapping AUC 95% CI suggests no benefit of a combined GFAP and UCH-L1 screening tool over GFAP during the time periods studied [0.87 (0.83-0.90) vs. 0.86 (0.82-0.90) when sampled within 6 h of injury, 0.83 (0.78-0.88) vs. 0.83 (0.78-0.89) within 6 to 9 h and 0.81 (0.73-0.88) vs. 0.79 (0.72-0.87) within 9-12 h]. Targeted analysis of the CENTER-TBI core database, with focus on the patient category for which biomarker testing is recommended by the SNC guidelines, revealed that GFAP and UCH-L1 perform superior to S100B in predicting CT-positive intracranial lesions within 6 h of injury. GFAP continued to exhibit superior predictive ability to S100B during the time periods studied. S100B displayed relatively unaltered screening performance beyond the diagnostic timeline provided by SNC guidelines. These findings suggest the need for a reevaluation of the current SNC TBI guidelines.

Navigating the Complexities of Traumatic Encephalopathy Syndrome (TES): Current State and Future Challenges

Chronic traumatic encephalopathy (CTE) is a unique neurodegenerative disease that is associated with repetitive head impacts (RHI) in both civilian and military settings. In 2014, the research criteria for the clinical manifestation of CTE, traumatic encephalopathy syndrome (TES), were proposed to improve the clinical identification and understanding of the complex neuropathological phenomena underlying CTE. This review provides a comprehensive overview of the current understanding of the neuropathological and clinical features of CTE, proposed biomarkers of traumatic brain injury (TBI) in both research and clinical settings, and a range of treatments based on previous preclinical and clinical research studies. Due to the heterogeneity of TBI, there is no universally agreed-upon serum, CSF, or neuroimaging marker for its diagnosis. However, as our understanding of this complex disease continues to evolve, it is likely that there will be more robust, early diagnostic methods and effective clinical treatments. This is especially important given the increasing evidence of a correlation between TBI and neurodegenerative conditions, such as Alzheimer's disease and CTE. As public awareness of these conditions grows, it is imperative to prioritize both basic and clinical research, as well as the implementation of necessary safe and preventative measures.

Biomarker S100B in plasma a screening tool for mild traumatic brain injury in an emergency department

INTRODUCTION

A computerized tomography (CT) scan is an effective test for detecting traumatic intracranial findings after mild traumatic brain injury (mTBI). However, a head CT is costly, and can only be performed in a hospital.

OBJECTIVE

To determine if the addition of plasma S100B to clinical guidelines could lead to a more selective scanning strategy without compromising safety.

METHODS

We conducted a single center prospective cohort study at the emergency department. Patients (≥16 years) who received head CT and had a blood draw were included. The primary outcome was the accuracy of plasma S100B to predict the presence of any traumatic intracranial lesion on head CT.

RESULTS

We included 495 patients, out of the 74 patients who had traumatic intracranial lesions, 5 patients had a plasma S100B level below the cutoff value of 0.105 ug/L. For the detection of traumatic intracranial injury, S100B had a sensitivity of 0.932 , a specificity of 0.157, a negative predictive value of 0.930, and a positive predictive value of 0.163.

CONCLUSIONS

Among patients undergoing guideline-based CT scan for mTBI, the use of S100B, would results in a further decrease (14.8%) of CT scans but at a cost of missed injury, without clinical consequence, on CT.

Implementation of the S100 Calcium-Binding Protein B Biomarker in a Clinical Setting: A Retrospective Study of Benefits, Safety, and Effectiveness

Recent years have seen the emergence of the S100 calcium-binding protein B (S100B) biomarker used in the initial management of minor traumatic brain injury (TBI) patients. S100B has been found to reduce cerebral computed tomography (CT-C) scans and was recently implemented in the Scandinavian Neurotrauma Committee (SNC) guidelines. In a clinical setup, we retrospectively investigated the use of the S100B biomarker in relation to the SNC guidelines in the respective year before and after implementation. Accordingly, minor TBI patients with the International Classification of Diseases, Tenth Revision diagnostic code of S06.0 commotio cerebri were included in 2018 (n = 786) and 2019 (n = 709) for comparison of emergency department time (EDT) and CT-Cs. In 2019, we included all patients with an S100B sample (n = 547; 348/199 male:female; median age, 52 years). We found an S100B sensitivity of 92% and negative predictive value (NPV) of 99% (cutoff, 0.10 μg/L) regardless of SNC guideline compliance. With strict SNC guideline management, sensitivity and NPV increased to 100%, even at a 0.20-μg/L cutoff that increased the specificity from 49% to 76%. After S100B implementation, we found the median EDT to significantly increase from 196 min (interquartile range [IQR] = 127–289) in 2018 to 216 min (IQR = 134.0–309.5) in 2019 (p = 0.0148), which may have resulted from poor guideline compliance (53.9%). Contrarily, the proportion of CT-C scanned patients decreased from 70% to 56.3% equal to a relative 27.5% decrease of scanned patients (p < 0.0001). Conclusively, our study supported the safe and efficient clinical use of the S100B biomarker, albeit with a minor EDT increase. S100B combination with the SNC guidelines improved clinical potential.

Progress Toward a Multiomic Understanding of Traumatic Brain Injury: A Review

Traumatic brain injury (TBI) is not a single disease state but describes an array of conditions associated with insult or injury to the brain. While some individuals with TBI recover within a few days or months, others present with persistent symptoms that can cause disability, neuropsychological trauma, and even death. Understanding, diagnosing, and treating TBI is extremely complex for many reasons, including the variable biomechanics of head impact, differences in severity and location of injury, and individual patient characteristics. Because of these confounding factors, the development of reliable diagnostics and targeted treatments for brain injury remains elusive. We argue that the development of effective diagnostic and therapeutic strategies for TBI requires a deep understanding of human neurophysiology at the molecular level and that the framework of multiomics may provide some effective solutions for the diagnosis and treatment of this challenging condition. To this end, we present here a comprehensive review of TBI biomarker candidates from across the multiomic disciplines and compare them with known signatures associated with other neuropsychological conditions, including Alzheimer’s disease and Parkinson’s disease. We believe that this integrated view will facilitate a deeper understanding of the pathophysiology of TBI and its potential links to other neurological diseases.

Alterations to the gut microbiome after sport-related concussion in a collegiate football players cohort: A pilot study

Concussions, both single and repetitive, cause brain and body alterations in athletes during contact sports. The role of the brain-gut connection and changes in the microbiota have not been well established after sports-related concussions or repetitive subconcussive impacts. We recruited 33 Division I Collegiate football players and collected blood, stool, and saliva samples at three time points throughout the athletic season: mid-season, following the last competitive game (post-season), and after a resting period in the off-season. Additional samples were collected from four athletes that suffered from a concussion. 16S rRNA sequencing of the gut microbiome revealed a decrease in abundance for two bacterial species, Eubacterium rectale, and Anaerostipes hadrus, after a diagnosed concussion. No significant differences were found regarding the salivary microbiome. Serum biomarker analysis shows an increase in GFAP blood levels in athletes during the competitive season. Additionally, S100β and SAA blood levels were positively correlated with the abundance of Eubacterium rectale species among the group of athletes that did not suffer a diagnosed concussion during the sports season. These findings provide initial evidence that detecting changes in the gut microbiome may help to improve concussion diagnosis following head injury.

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A longitudinal study following college football athletes across a sports season.

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Nanopore 16S rRNA sequencing of gut microbiome reveals changes after head injury.

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Serum biomarker GFAP increased during the competitive period of the season.

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S100β and SAA blood levels were positively correlated with Eubacterium rectale.

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Gut microbiota is suggested as a future biomarker for diagnosis following head injury.

Can serum biomarkers be used to rule out significant intracranial pathology in emergency department patients with mild traumatic brain injury? A Systemic Review & Meta-Analysis

BACKGROUND

Interest has mounted into the use of objective clinical biomarkers for traumatic brain injury (TBI). This systematic review and meta-analysis aimed to synthesise the existing evidence investigating the use of serum & plasma biomarkers to exclude significant intracranial injuries seen on CT head scans in patients that present to ED with TBI.

METHODS

The primary outcome was to review the diagnostic accuracy (sensitivity & specificity) of S100B, GFAP and UCH-L1 to exclude significant intracranial pathology on CT head scan in adults presenting with TBI. Secondary outcomes investigated biomarker performance at different time points, in isolated TBI and multi-trauma and with pre-specified cut offs. Systematic searches were conducted on MEDLINE ® (via PubMed), Cochrane electronic databases and EMBASE from 1^st January 2000 until June 2020. Bias was assessed using QUADAS 2 tool. A narrative synthesis and meta-analysis were performed. PROSPERO registration number CRD42020212206.

RESULTS

After screening, 22 papers were included. The total number of patients with TBI was 9,416. There was significant variation regarding study design, population selection and the clinical threshold/decision rule for CT head request. The diagnostic accuracy of S100B as measured by the range of individual sensitivities and specificities were 63-100% and 5-58%, respectively. Individual sensitivities and specificities for GFAP were 67-100% and 0-89% and for UCH-L1 were 61-100% and 21-63.7% respectively. When measured within 3 hours individual sensitivities & specificities for S100B were 98-100% & 20-58% respectively. The quality of evidence for the primary outcome overall was low. The quality of evidence was low for all secondary outcomes apart from studies that used a pre-specified cut off for S100B which had a moderate strength of evidence.

CONCLUSION

The overall quality of evidence regarding the diagnostic accuracy of single biomarkers as a rule out for significant intracranial injury seen on CT head scans in ED patients with TBI is low. Based on current evidence, S100B is the only single biomarker with a validated clinical platform, pre-determined cut off threshold and moderate quality evidence; at this stage making it the biomarker of choice. More robust clinical outcome and economic impact data is required to support its incorporation into clinical decision tools.

Aldolase C Profiling in Serum after Mild Traumatic Brain Injury: A Prospective Cohort Study

BACKGROUND

After a traumatic brain injury (TBI), in addition to clinical indices, the serum level of neurological biomarkers may provide valuable diagnostic and prognostic information. The present study aimed to investigate the aldolase C (ALDOC) profile in serum for early diagnosis of brain damage in patients with mild TBI (mTBI) presented to the Emergency Department (ED).

METHODS

A single-center prospective cohort study was carried out in 2018-2019 at Imam Khomeini Hospital affiliated with Mazandaran University of Medical Sciences, Sari, Iran. A total of 89 patients with mTBI were enrolled in the study. Blood samples were taken within three hours after head trauma to measure ALDOC serum levels. Brain CT scan was used as the gold standard. Statistical analysis was performed using the Kruskal Wallis, Mann-Whitney U, and Chi square tests. The receiver-operating characteristic (ROC) curve plot was used to determine the optimal cutoff point for ALDOC. The sensitivity and specificity of the determined cutoff point were calculated. P values less than 0.05 were considered statistically significant.

RESULTS

Of the 89 patients, the CT scan findings showed a positive TBI in 30 (33.7%) of the patients and in 59 (66.3%) a negative TBI. The median ALDOC serum level in the patients with positive CT scan findings (8.35 ng/mL [IQR: 1.65]) was significantly higher than those with negative CT scan findings (5.3 ng/mL [IQR: 6.9]) (P<0.001). The optimal cutoff point for ALDOC serum level was 6.95 ng/mL, and the area under the curve was 99.6% (P<0.001). The sensitivity and specificity of the determined cutoff point were 100% and 98%, respectively.

CONCLUSION

The ALDOC serum level in patients with mTBI significantly correlates with the pathologic findings of the brain CT scan. This biomarker, with 100% sensitivity, is a suitable tool to detect brain structural abnormalities in mTBI patients.

S100B, GFAP, UCH-L1 and NSE as predictors of abnormalities on CT imaging following mild traumatic brain injury: a systematic review and meta-analysis of diagnostic test accuracy

Biomarkers such as calcium channel binding protein S100 subunit beta (S100B), glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1) and neuron-specific enolase (NSE) have been proposed to aid in screening patients presenting with mild traumatic brain injury (mTBI). As such, we aimed to characterise their accuracy at various thresholds. MEDLINE, SCOPUS and EMBASE were searched, and articles reporting the diagnostic performance of included biomarkers were eligible for inclusion. Risk of bias was assessed using the QUADAS-II criteria. A meta-analysis was performed to assess the predictive value of biomarkers for imaging abnormalities on CT. A total of 2939 citations were identified, and 38 studies were included. Thirty-two studies reported data for S100B. At its conventional threshold of 0.1 μg/L, S100B had a pooled sensitivity of 91% (95%CI 87-94) and a specificity of 30% (95%CI 26-34). The optimal threshold for S100B was 0.72 μg/L, with a sensitivity of 61% (95% CI 50-72) and a specificity of 69% (95% CI 64-74). Nine studies reported data for GFAP. The optimal threshold for GFAP was 626 pg/mL, at which the sensitivity was 71% (95%CI 41-91) and specificity was 71% (95%CI 43-90). Sensitivity of GFAP was maximised at a threshold of 22 pg/mL, which had a sensitivity of 93% (95%CI 73-99) and a specificity of 36% (95%CI 12-68%). Three studies reported data for NSE and two studies for UCH-L1, which precluded meta-analysis. There is evidence to support the use of S100B as a screening tool in mild TBI, and potential advantages to the use of GFAP, which requires further investigation.

Blood-Brain Barrier Dysfunction in CNS Disorders and Putative Therapeutic Targets: An Overview

The blood-brain barrier (BBB) is a fundamental component of the central nervous system (CNS). Its functional and structural integrity is vital to maintain the homeostasis of the brain microenvironment by controlling the passage of substances and regulating the trafficking of immune cells between the blood and the brain. The BBB is primarily composed of highly specialized microvascular endothelial cells. These cells’ special features and physiological properties are acquired and maintained through the concerted effort of hemodynamic and cellular cues from the surrounding environment. This complex multicellular system, comprising endothelial cells, astrocytes, pericytes, and neurons, is known as the neurovascular unit (NVU). The BBB strictly controls the transport of nutrients and metabolites into brain parenchyma through a tightly regulated transport system while limiting the access of potentially harmful substances via efflux transcytosis and metabolic mechanisms. Not surprisingly, a disruption of the BBB has been associated with the onset and/or progression of major neurological disorders. Although the association between disease and BBB disruption is clear, its nature is not always evident, specifically with regard to whether an impaired BBB function results from the pathological condition or whether the BBB damage is the primary pathogenic factor prodromal to the onset of the disease. In either case, repairing the barrier could be a viable option for treating and/or reducing the effects of CNS disorders. In this review, we describe the fundamental structure and function of the BBB in both healthy and altered/diseased conditions. Additionally, we provide an overview of the potential therapeutic targets that could be leveraged to restore the integrity of the BBB concomitant to the treatment of these brain disorders.

Cerebral, cardiac and skeletal muscle stress associated with a series of static and dynamic apnoeas

PURPOSE

This study sought to explore, for the first time, the effects of repeated maximal static and dynamic apnoeic attempts on the physiological milieu by assessing cerebral, cardiac and striatal muscle stress-related biomarkers in a group of elite breath-hold divers (EBHD).

METHODS

Sixteen healthy males were recruited (EBHD = 8; controls = 8). On two separate occasions, EBHD performed two sets of five repeated maximal static apnoeas (STA) or five repeated maximal dynamic apnoeas (DYN). Controls performed a static eupnoeic protocol to negate any effects of water immersion and diurnal variation on haematology (CTL). Venous blood samples were drawn at 30, 90, and 180 min after each protocol to determine S100β, neuron-specific enolase (NSE), myoglobin, and high sensitivity cardiac troponin T (hscTNT) concentrations.

RESULTS

S100β and myoglobin concentrations were elevated following both apnoeic interventions (p < 0.001; p ≤ 0.028, respectively) but not after CTL (p ≥ 0.348). S100β increased from baseline (0.024 ± 0.005 µg/L) at 30 (STA, +149%, p < 0.001; DYN, +166%, p < 0.001) and 90 min (STA, +129%, p < 0.001; DYN, +132%, p = 0.008) following the last apnoeic repetition. Myoglobin was higher than baseline (22.3 ± 2.7 ng/ml) at 30 (+42%, p = 0.04), 90 (+64%, p < 0.001) and 180 min (+49%, p = 0.013) post-STA and at 90 min (+63%, p = 0.016) post-DYN. Post-apnoeic S100β and myoglobin concentrations were higher than CTL (STA, p < 0.001; DYN, p ≤ 0.004). NSE and hscTNT did not change from basal concentrations after the apnoeic (p ≥ 0.146) nor following the eupnoeic (p ≥ 0.553) intervention.

CONCLUSIONS

This study suggests that a series of repeated maximal static and dynamic apnoeas transiently disrupt the blood-brain barrier and instigate muscle injury but do not induce neuronal-parenchymal damage or myocardial damage.

Plasma-based S100B testing for management of traumatic brain injury in emergency setting

Background

Serum biomarker S100B has been explored for its potential benefit to improve clinical decision-making in the management of patients suffering from traumatic brain injury (TBI), especially as a pre-head computed-tomography screening test for patients with mild TBI. Although being already included into some guidelines, its implementation into standard care is still lacking. This might be explained by a turnaround time (TAT) too long for serum S100B to be used in clinical decision-making in emergency settings.

Methods

S100B concentrations were determined in 136 matching pairs of serum and lithium heparin blood samples. The concordance of the test results was assessed by linear regression, Passing Pablok regression and Bland-Altman analysis. Bias and within- and between-run imprecision were determined by a 5 × 4 model using pooled patient samples. CT scans were performed as clinically indicated.

Results

Overall, S100B levels between both blood constituents correlated very well. The suitability of S100B testing from plasma was verified according to ISO15189 requirements. Using a cut-off of 0.105 ng/ml, a sensitivity and negative predictive value of 100% were obtained for identifying patients with pathologic CT scans. Importantly, plasma-based testing reduced the TAT to 26 min allowing for quicker clinical decision-making. The clinical utility of integrating S100B in TBI management is highlighted by two case reports.

Conclusions

Plasma-based S100B testing compares favorably with serum-based testing, substantially reducing processing times as the prerequisite for integrating S100B level into management of TBI patients. The proposed new clinical decision algorithm for TBI management needs to be validated in further prospective large-scale studies.

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Plasma-based S100B testing reduces turnaround time to 26 minutes and thus enables its use in the emergency department.

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Plasma- and serum-based S100B testing demonstrate commutability of results.

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Clinical cases demonstrate the benefit of elevated S100B levels as an indicator for second-look CT re-evaluation.

Molecular and Diffusion Tensor Imaging Biomarkers of Traumatic Brain Injury: Principles for Investigation and Integration

The last 20 years have seen the advent of new technologies that enhance the diagnosis and prognosis of traumatic brain injury (TBI). There is recognition that TBI affects the brain beyond initial injury, in some cases inciting a progressive neuropathology that leads to chronic impairments. Medical researchers are now searching for biomarkers to detect and monitor this condition. Perhaps the most promising developments are in the biomolecular and neuroimaging domains. Molecular assays can identify proteins indicative of neuronal injury and/or degeneration. Diffusion imaging now allows sensitive evaluations of the brain's cellular microstructure. As the pace of discovery accelerates, it is important to survey the research landscape and identify promising avenues of investigation. In this review, we discuss the potential of molecular and diffusion tensor imaging (DTI) biomarkers in TBI research. Integration of these technologies could advance models of disease prognosis, ultimately improving care. To date, however, few studies have explored relationships between molecular and DTI variables in patients with TBI. Here, we provide a short primer on each technology, review the latest research, and discuss how these biomarkers may be incorporated in future studies.

Peripheral Blood and Salivary Biomarkers of Blood-Brain Barrier Permeability and Neuronal Damage: Clinical and Applied Concepts

Within the neurovascular unit (NVU), the blood–brain barrier (BBB) operates as a key cerebrovascular interface, dynamically insulating the brain parenchyma from peripheral blood and compartments. Increased BBB permeability is clinically relevant for at least two reasons: it actively participates to the etiology of central nervous system (CNS) diseases, and it enables the diagnosis of neurological disorders based on the detection of CNS molecules in peripheral body fluids. In pathological conditions, a suite of glial, neuronal, and pericyte biomarkers can exit the brain reaching the peripheral blood and, after a process of filtration, may also appear in saliva or urine according to varying temporal trajectories. Here, we specifically examine the evidence in favor of or against the use of protein biomarkers of NVU damage and BBB permeability in traumatic head injury, including sport (sub)concussive impacts, seizure disorders, and neurodegenerative processes such as Alzheimer's disease. We further extend this analysis by focusing on the correlates of human extreme physiology applied to the NVU and its biomarkers. To this end, we report NVU changes after prolonged exercise, freediving, and gravitational stress, focusing on the presence of peripheral biomarkers in these conditions. The development of a biomarker toolkit will enable minimally invasive routines for the assessment of brain health in a broad spectrum of clinical, emergency, and sport settings.

S100B protein level for the detection of clinically significant intracranial haemorrhage in patients with mild traumatic brain injury: a subanalysis of a prospective cohort study

Background

Clinical assessment of patients with mild traumatic brain injury (mTBI) is challenging and overuse of head CT in the ED is a major problem. Several studies have attempted to reduce unnecessary head CTs following a mTBI by identifying new tools aiming to predict intracranial bleeding. Higher levels of S100B protein have been associated with intracranial haemorrhage following a mTBI in previous literature. The main objective of this study is to assess whether plasma S100B protein level is associated with clinically significant brain injury and could be used to reduce the number of head CT post-mTBI.

Methods

Study design: secondary analysis of a prospective multicentre cohort study conducted between 2013 and 2016 in five Canadian EDs. Inclusion criteria: non-hospitalised patients with mTBI with a GCS score of 13–15 in the ED and a blood sample drawn within 24 hours after the injury. Data collected: sociodemographic and clinical data were collected in the ED. S100B protein was analysed using ELISA. All CT scans were reviewed by a radiologist blinded to the biomarker results. Main outcome: the presence of clinically important brain injury.

Results

476 patients were included. Mean age was 41±18 years old and 150 (31.5%) were women. Twenty-four (5.0%) patients had a clinically significant intracranial haemorrhage. Thirteen patients (2.7%) presented a non-clinically significant brain injury. A total of 37 (7.8%) brain injured patients were included in our study. S100B median value (Q1–Q3) was: 0.043 µg/L (0.008–0.080) for patients with clinically important brain injury versus 0.039 µg/L (0.023–0.059) for patients without clinically important brain injury. Sensitivity and specificity of the S100B protein level, if used alone to detect clinically important brain injury, were 16.7% (95% CI 4.7% to 37.4%) and 88.5% (95% CI 85.2% to 91.3%), respectively.

Conclusion

Plasma S100B protein level was not associated with clinically significant intracranial lesion in patients with mTBI.

S100B Blood Level Determination for Early Management of Ski-Related Mild Traumatic Brain Injury: A Pilot Study

Background: Mild traumatic brain injury (mTBI) management in emergency departments is a complex process involving clinical evaluation, laboratory testing, and computerized tomography (CT) scanning. Protein S100B has proven to be a useful blood biomarker for early evaluation of mTBI, as it reduces the required CT scans by one-third. However, to date, the ability of S100B to identify positive abnormal findings in the CT scans of patients suffering from mTBI caused by ski practice has not been investigated. Thus, the primary aim of this study was to investigate the diagnostic performance of S100B as an mTBI management biomarker in patients with ski-related mTBI.

Materials and Methods: One hundred and thirty adult mTBI patients presenting to the emergency department of Hôpital du Valais in Sion, Switzerland, with a Glasgow Coma Scale (GCS) score of 13–15 and clinical indication for a CT scan were included in the study. Blood samples for S100B measurement were collected from each patient and frozen in 3-hour post-injury intervals. CT scans were performed for all patients. Later, serum S100B levels were compared to CT scan findings in order to evaluate the biomarker's performance.

Results: Of the 130 included cases of mTBI, 87 (70%) were related to ski practice. At the internationally established threshold of 0.1 μg/L, the receiver operating characteristic curve of S100B serum levels for prediction of abnormal CT scans showed 97% sensitivity, 11% specificity, and a 92% negative predictive value. Median S100B concentrations did not differ according to sex, age, or GCS score. Additionally, there was no significant difference between skiers and non-skiers. However, a statistically significant difference was found when comparing the median S100B concentrations of patients who suffered fractures or had polytrauma and those who did not suffer fractures.

Conclusion: The performance of S100B in post-mTBI brain lesion screenings seems to be affected by peripheral lesions and/or ski practice. The lack of neurospecificity of the biomarker in this context does not allow unnecessary CT scans to be reduced by one-third as expected.

Central nervous system diseases associated with blood brain barrier breakdown - A Comprehensive update of existing literatures

Blood vessels that supply and feed the central nervous system (CNS) possess unique and exclusive properties, named as blood–brain barrier (BBB). It is responsible for tight regulation of the movement of ions, molecules, and cells between the blood and the brain thereby maintaining controlled chemical composition of the neuronal milieu required for appropriate functioning. It also protects the neural tissue from toxic plasma components, blood cells and pathogens from entering the brain. In this review the importance of BBB and its disruption causing brain pathology and progression to different neurological diseases like Alzheimer’s disease (AD), Parkinson’s disease (PD), Amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD) etc. will be discussed.

Management of Traumatic Brain Injury: From Present to Future

TBI (traumatic brain injury) is a major cause of death among youth in industrialized societies. Brain damage following traumatic injury is a result of direct and indirect mechanisms; indirect or secondary injury involves the initiation of an acute inflammatory response, including the breakdown of the blood–brain barrier (BBB), brain edema, infiltration of peripheral blood cells, and activation of resident immunocompetent cells, as well as the release of numerous immune mediators such as interleukins and chemotactic factors. TBI can cause changes in molecular signaling and cellular functions and structures, in addition to tissue damage, such as hemorrhage, diffuse axonal damages, and contusions. TBI typically disturbs brain functions such as executive actions, cognitive grade, attention, memory data processing, and language abilities. Animal models have been developed to reproduce the different features of human TBI, better understand its pathophysiology, and discover potential new treatments. For many years, the first approach to manage TBI has been treatment of the injured tissue with interventions designed to reduce the complex secondary-injury cascade. Several studies in the literature have stressed the importance of more closely examining injuries, including endothelial, microglia, astroglia, oligodendroglia, and precursor cells. Significant effort has been invested in developing neuroprotective agents. The aim of this work is to review TBI pathophysiology and existing and potential new therapeutic strategies in the management of inflammatory events and behavioral deficits associated with TBI.

Increased S-100 B levels are associated with fractures and soft tissue injury in multiple trauma patients

BACKGROUND

S-100 B protein was identified as a biomarker for traumatic brain injury, but studies suggest that extracranial injuries may also lead to increased S-100 B serum levels. In this study, we aim to quantify the impact of injury patterns on S-100 B levels in patients with suspected multiple trauma.

METHODS

Patients with suspected multiple trauma treated at a Level 1 Trauma centre in Switzerland were included in this retrospective patient chart review. Extent of injuries and severity was assessed and S-100 B levels on admission measured. Potential predictors of increased S-100 B levels (>0.2 µg/L) were identified through uni- and multivariable analyses.

RESULTS

In total, 1,338 patients with suspected multiple trauma were included. Multivariable logistic regression showed a significant association with increased S-100 B levels in long bone fracture (OR 2.3, 95% CI: 1.3-4.1, p = 0.004), non-long bone fracture (OR 3.0, 95% CI: 2.2-4.3, p<0.001), thoracic injury (OR 2.6, 95% CI: 1.6-4.2, p<0.001), and deep tissue injury/wounds (OR 1.9, 95% CI: 1.4-2.6, p<0.001). Head trauma with intracerebral bleeding was only weakly associated (OR 2.0, 95% CI 1.2-3.5, p = 0.01) and head trauma without intracranial bleeding was not associated with an increased S-100 B protein level (p = 0.71). Trauma severity was also related to increased S-100 B levels (OR per ISS: 1.1, 95% CI 1.0-1.1, p<0.001). S-100 B levels <0.57 µg/L had a high diagnostic value to rule out in-hospital mortality (negative predictive value: 1.0, 95% CI: 0.98-1.00).

CONCLUSION

Fractures and thoracic injuries appeared as main factors associated with increased S-100 B levels. Head injury may only play a minor role in S-100 B protein elevation in multiple trauma patients. A normal S-100 B has a good negative predictive value for in-hospital mortality. S100-B levels were associated with trauma severity and might thus be of use as a prognostic marker in trauma patients.

Proteomic examination of the neuroglial secretome: lessons for the clinic

Introduction: Glial cells are closely associated with neurons located throughout the nervous system and regulate neuronal activity and function through various mechanisms including the secretion of proteins and other signaling molecules. Glia-secreted proteins play crucial roles in modulating neuronal function in physiological and pathological conditions. Aberrant activation of glial cells leading to neuroinflammation is a common phenomenon observed in various neurological disorders. Aberrantly activated glial cells secrete proteins in disease-specific manner and can be exploited as a repository for novel biomarker discovery.Areas covered: In this review, we describe the recent advances in proteomic techniques, highlighting the need for their application to the secretomic field. Studies regarding the secretome profile of glial cells published within the last 5 years are discussed in detail. The use of glia-based biomarkers in various neuroinflammatory and neurodegenerative diseases is also discussed.Expert opinion: Precise diagnosis and timely treatment of neurological disorders remains a challenge and glia-focused research to identify specific biomarkers appears to be a promising approach to combat these disorders. Recent technological advancement in proteomic research would open new frontiers for more rigorous analysis of glial secretome variations over time and the discovery/development of novel biomarkers for neurological disorders.

S-100β in predicting the need of hyperbaric oxygen in CO-induced delayed neurological sequels

BACKGROUND

Delayed neurological sequels (DNS) have been described after carbon monoxide (CO) poisoning. There is a need to find a new prognostic marker to guide the use of hyperbaric oxygen (HBO) therapy.

AIM

To evaluate serum S-100β level in patients presenting with acute CO poisoning as an indicator of poisoning severity and predictor of DNS occurrence and HBO need in those patients.

METHODS

This prospective cohort study included patients with acute CO poisoning. On admission, carboxyhemoglobin (COHb) and S-100β levels were measured. Patients were followed up for 6 months for signs of DNS.

RESULTS

Out of 50 patients, 6 only developed DNS. The mean of S-100β levels was significantly higher in patients with severe poisoning and those with DNS. Receiver operating characteristic curve analysis revealed that S-100β had an area under the curve 0. 871; at a cutoff value ≥ 0.67 µg/L, its sensitivity and specificity were 100% and 77.3%, respectively. The sensitivity of S-100β was significantly higher than that of COHb, while its specificity and overall accuracy were significantly higher than those of HBO criteria.

CONCLUSION

Serum S-100β level on admission could be a marker of poisoning severity and a predictor of CO-induced DNS development that guides the use of HBO therapy.

The utility of S100B level in detecting mild traumatic brain injury in intoxicated patients

BACKGROUND

S100B is a serum protein known to elevate in patients with brain injury, but it is unknown whether it can predict intracranial pathology in intoxicated patients following mild traumatic brain injury (MTBI). We performed a systematic review and meta-analysis of the English language literature to address this question.

MAIN OUTCOMES AND RESULTS

Four prospective cohort trials of serum S100B levels on acutely intoxicated patients with MTBI were included in this meta-analysis. Prevalence of intracranial pathology in the pooled cohort of the intoxicated MTBI patients was 10%, lower than the 15-30% reported in the literature for the general MTBI population. Standard mean difference of serum S100B levels between patients with and without intracranial pathology on CT was 0.73 μg/L (Z = 18.33, P < 0.001). Following sensitivity analysis and hierarchical summary receiver-operating characteristic models, three remaining articles were used for pooled estimates that found that S100B had a sensitivity of 0.96 (95% CI: 0.84-1.00, I2 = 0%) and specificity of 0.63 (95% CI: 0.58-0.68, I2 = 86.8%) with a high negative predictive value (100%, 95% CI: 95.14-100, I2 = 0%) and a negative LR of 0.06 (95% CI: 0.01-0.31).

CONCLUSIONS

Serum S100B levels may have utility in ruling out intracranial pathology in intoxicated patients, however more study and comparison with other serum biomarkers of brain injury are necessary before this becomes the accepted standard of care.

Stress and lasting symptoms following injury: Results from a 4-month cohort of trauma patients recruited at the emergency department

INTRODUCTION

Recent research suggests that up to 20% of minor trauma patients admitted to the emergency department (ED) will suffer from non-specific chronic conditions over the subsequent several months. Thus, the present study assessed the correlates of symptoms that persisted at 4 months after an ED visit and, in particular, evaluated the associations between these symptoms and self-reported stress levels at ED admission and discharge.

METHOD

This study was a prospective observational investigation conducted in the ED of Bordeaux University Hospital that included patients admitted for minor trauma. All participants were contacted by phone 4 months after presentation at the ED to assess the occurrence of post-concussion-like symptoms (PCLS).

RESULTS

A total of 193 patients completed the follow-up assessment at 4 months; 5.2% of the participants suffered from post-traumatic stress disorder (PTSD) and 24.5% suffered from PCLS. A multivariate analysis revealed an association between PCLS and stress level at discharge from the ED (odds ratios [OR]: 2.85, 95% confidence interval [CI]: 1.10-7.40).

CONCLUSIONS

The risk of PCLS at 4 months after an ED visit for a minor injury increased in association with the level of stress at discharge from the ED. These results may improve the quality of life for the millions of patients who experience a stressful injury event every year.

Features of urine S100B and its ability to rule out intracranial hemorrhage in patients with head trauma: a prospective trial

Purpose

Traumatic brain injury causes morbidity and mortality worldwide. S100B is the most documented emergency brain biomarker and its urine-assay might be advantageous because of easier sampling. The primary aim was to evaluate urine S100B’s ability to rule out intracranial hemorrhage. Secondary aims included S100B temporal pattern for 48 h post-trauma and chemical properties of urine that affect urine S100B.

Methods

Patients with head trauma were sampled for serum and urine S100B. Patients who were admitted for intracranial hemorrhage were sampled for 48 h to assess S100B-level, renal function, urine-pH, etc.

Results

The negative predictive value of serum S100B was 97.0% [95% confidence interval (CI) 89.5–99.2%] and that of urine S100B was 89.1% (95% CI 85.5–91.9%). The specificity of serum S100B was 34.4% (95% CI 27.7–41.6%) and that of urine was 67.1% (95% CI 59.4–74.1%). Urine-pH correlated strongly with urine S100B during the first 6-h post-trauma. Trend-analysis of receiver operator characteristics of S100B in serum, urine the arithmetic difference between serum and urine S100B showed the largest area under the curve for arithmetic difference, which had a negative predictive value of 93.1% (95% CI 89.1–95.8%) and a specificity of 71.8% (95% CI 64.4–78.4%).

Conclusion

This study cannot support ruling out intracranial hemorrhage with urine S100B. Urine-pH might affect urine S100B and merits further studies. Serum and urine S100B have poor concordance and interchangeability. The arithmetic difference had a slightly better area under the curve and can be worth exploring in certain subgroups.

Neuroprotective Effects of Kinin B2 Receptor in Organotypic Hippocampal Cultures of Middle-Aged Mice

Aging is a multifactorial phenomenon that results in several changes at cellular and molecular levels and is considered the main risk factor for some neurodegenerative diseases. Several evidence show the participation of the kallikrein-kinin system (KKS) in neurodegeneration and this system has been associated with inflammation and immunogenic responses in the central and peripheral systems by the activation of the B1 and B2 receptors. Previous work by our group showed that bradykinin (BK) and the B2 receptor played a possible role in neuroprotection. Therefore, the objective of this study was to evaluate the participation of B2 receptors in cell viability, neuroinflammatory response and neuroplasticity in organotypic hippocampal cultures (OHCs) of 6- and 12-month-old mice. It was observed that activation of the B2 receptor by bradykinin decreased the inflammatory response and increased plasticity in 12-month-old slices. Conversely, there was an increase in the inflammatory response and a decrease in neural plasticity in the 6-month-old slices. In both ages, an increase in cell viability was observed. This data suggests that the function of the kinin B2 receptor in the hippocampus is modulated by age, providing neuroprotective action in old age.

Detection of S-100β Protein in Plasma and Urine After a Mild Traumatic Brain Injury

This study assessed whether S-100β protein could be measured in urine when detectable in plasma after a mild traumatic brain injury (mTBI). Clinical data, plasma and urine samples were collected for the 46 adult patients prospectively enrolled in the emergency department (ED) of a Level 1 trauma center. S-100β protein concentrations were analysed using ELISA. S-100β protein was detectable in 91% and 71% of plasma and urine samples, but values were not correlated (r = 0.002). Urine sampling would have been a non-invasive procedure, but it does not appear to be useful in the ED during the acute phase after an mTBI.

Increased Serum S100B Levels in Patients With Epilepsy: A Systematic Review and Meta-Analysis Study

Importance: Accumulating evidence suggests that serum levels of S100B may play a role in epilepsy. Objective: We performed a meta-analysis to quantitatively summarize the serum S100B data available for patients with epilepsy. Data source: Two independent researchers conducted a systematic investigation of the Harvard Hollis+, Open Gray, Clinicaltrials, Wanfangdata, and CNKI databases through Dec 6, 2018, for all studies published in English and Chinese. The search terms included S100B and calcium-binding protein B in combination with epilepsy. Study selection: Original studies and reported data from these search terms are included. Studies where data overlapped with other studies were excluded. Data extraction and synthesis: investigators extracted, pooled and analyzed data from the included studies using a fixed-effects model in the Comprehensive Meta-Analysis3.3 and R software. Main outcomes and measures: Peripheral blood levels of S100B in patients with epilepsy compared with controls. Aberrations in peripheral blood levels of S100B were hypothesized to be related to epilepsy. Results: a fixed-effects meta-analysis of all 18 studies, including 1,057 unique participants, indicated that patients with epilepsy had significantly increased peripheral blood levels of S100B compared to controls (Hedges g = 1.568, 95% CI =1.431-1.706, P < 0.001). Sensitivity analysis showed that no single study significantly influenced the overall association of peripheral blood levels of S100B and epilepsy. Most of the subgroup analyses, including those of country, assay type and publication language, demonstrated a statistically significant association between peripheral blood levels of S100B and epilepsy. Meta-regression analyses indicated that gender (regression coefficient [SE], -0.2524 [0.0641]; 95%CI, -0.3781 to -0.1267; P = 0.0001) and mean age (regression coefficient [SE], -0.1224 [0.0426]; 95% CI, -0.2058 to -0.0390; P = 0.0040) might present serum S100B reductions, but sample size, years, assay type, publication language and country did not show moderating effects on the effect sizes. Furthermore, the trim-and-fill method used to adjust for funnel plot asymmetry in our meta-analysis confirmed that a positive outcome is unlikely to be due to publication bias. Conclusion and relevance: the results of this meta-analysis provide evidence for a significant increase in serum S100B levels in patients with epilepsy. Serum S100B is the most worthwhile biomarker of epilepsy, which is helpful for the clinical diagnosis and prognosis of epilepsy.

Early Levels of Glial Fibrillary Acidic Protein and Neurofilament Light Protein in Predicting the Outcome of Mild Traumatic Brain Injury

The purpose of this study was to correlate the early levels of glial fibrillary acidic protein (GFAP) and neurofilament light protein (NF-L) with outcome in patients with mild traumatic brain injury (mTBI). A total of 107 patients with mTBI (Glasgow Coma Scale ≥13) who had blood samples for GFAP and NF-L available within 24 h of arrival were included. Patients with mTBI were divided into computed tomography (CT)-positive and CT-negative groups. Glasgow Outcome Scale-Extended (GOSE) was used to assess the outcome. Outcomes were defined as complete (GOSE 8) versus incomplete (GOSE <8), and favorable (GOSE 5-8) versus unfavorable (GOSE 1-4). GFAP and NF-L concentrations in blood were measured using ultrasensitive single molecule array technology. Patients with incomplete recovery had significantly higher levels of NF-L compared with those with complete recovery (p = 0.005). The levels of GFAP and NF-L were significantly higher in patients with unfavorable outcome than in patients with favorable outcome (p = 0.002 for GFAP and p < 0.001 for NF-L). For predicting favorable outcome, the area under the receiver operating characteristic curve for GFAP and NF-L was 0.755 and 0.826, respectively. In a multi-variate logistic regression model, the level of NF-L was still a significant predictor for complete recovery (odds ratio [OR] = 1.008; 95% confidence interval [CI], 1.000-1.016). Moreover, the level of NF-L was a significant predictor for complete recovery in CT-positive patients (OR = 1.009; 95% CI, 1.001-1.016). The early levels of GFAP and NF-L are significantly correlated with the outcome in patients with mTBI. The level of NF-L within 24 h from arrival has a significant predictive value in mTBI also in a multi-variate model.

Clinical Use of the Calcium-Binding S100B Protein, a Biomarker for Head Injury

S100B is a calcium-binding protein most abundant in neuronal tissue. It is expressed in glial cells and Schwann cells and exerts both intra- and extracellular effects. Depending on the concentration, secreted S100B exerts either trophic or toxic effects. Its functions have been extensively studied but are still not fully understood. It can be measured in cerebrospinal fluid and in blood, and increased S100B level in blood can be seen after, e.g., traumatic brain injury, certain neurodegenerative disorders, and malignant melanoma. This chapter provides a short background of protein S100B, commercially available methods of analysis, and its clinical use, especially as a biomarker in minor head injury.

Utility and effectiveness of the Scandinavian guidelines to exclude computerized tomography scanning in mild traumatic brain injury - a prospective cohort study

Background

In 2013 the Scandinavian Neurotrauma Committee (SNC) published updated guidelines for the initial management of minimal, mild and moderate traumatic head injuries (MTHI) that included serum analysis of protein S100B as a marker for brain tissue damage. This study reviews the effectiveness of the new guidelines in a clinical setting.

Methods

For all patients admitted to Akershus University Hospital (AHUS) from June 30th 2014 to December 15th 2014 with MTHI a separate form was filled in recording the time, indication and result of any S100B sampling and/or head computer tomography (CT) examinations. Data from these forms were compared to information derived from the electronic patient records for patients with MTHI and related diagnoses and data from the laboratory for all patients that had undergone the S100B analysis within the same period.

Results

Five hundred seventy-five patients were identified with MTHI, S100B sampling was indicated for 223 (38.8%) patients and carried out for 188 (84.3%) of these patients. 69 (36.7%) of the patients had a negative S100B test, but a head CT scan was still performed in 31 cases despite the negative S100B test. In total the guidelines were followed for 362 of 575 patients (63.0%). 180 (31.3%) of the MTHI cases were discharged without further observation or CT examinations, including 38 (21.1%) as a direct result of S100B testing. No re-admissions or missed initial traumatic brain injuries were observed.

Conclusion

The implementation of the updated SNC guidelines resulted in direct discharge of more than one third of the MTHI cases without further observation or CT examinations. One in five of these discharges was a direct result of S100B testing. However, compliance to the guidelines were poor and the guidelines were only followed in 40%. While this study showed benefits of implementing SNC guidelines to reduce the number of CT scans, additional training is needed for optimal use.

Clinical validation of S100B in the management of a mild traumatic brain injury: issues from an interventional cohort of 1449 adult patients

Background:

This study’s primary objective was to validate the routine use of S100B via a prospective study. The aim was a reduction of cranial computed tomography (CCT) scans by 30%. The secondary goal was to investigate the influence of age and associated risk factors on the reduction of CCT.

Methods:

S100B (sampling within 3 h postinjury) was used for patients with mild traumatic brain injury (mTBIs) presenting a medium risk of complications and requiring a CCT scan. Patients with negative S100B (S100B−) were discharged without a CCT scan.

Results:

Of the 1449 patients included in this study, 468 (32.3%) had S100B− with a sensitivity of 96.4% (95% CI: 87.5%–99.6%), a specificity of 33.4% (95% CI: 31%–36%) and a negative predictive value of 99.6% (95% CI: 98.5%–99.9%). No significant difference in serum levels or the S100B+ rate was observed if patients had retrograde amnesia (0.16 μg/L; 63.8%), loss of consciousness (0.13; 63.6%) or antiplatelet therapy (0.20; 77.9%). Significant differences were found between the S100B concentrations and S100B positivity rates in patients >65 years old and all the groups with patients <55 years old (18–25, 26–35, 36–45 and 46–55). From 18 to 65 years old (n=874), the specificity is 39.3% (95% CI: 36%–42.6%) compared to 18.7% (95% CI: 15.3%–22.3%) for patients >65 years old (n=504).

Conclusions:

The clinical use of S100B in mTBI management reduces the use of CCTs by approximately one-third; furthermore, the percentage of CCTs reduction is influenced by the age of the patient.

Blood-Based Protein Biomarkers for the Management of Traumatic Brain Injuries in Adults Presenting to Emergency Departments with Mild Brain Injury: A Living Systematic Review and Meta-Analysis

Accurate diagnosis of traumatic brain injury (TBI) is critical to effective management and intervention, but can be challenging in patients with mild TBI. A substantial number of studies have reported the use of circulating biomarkers as signatures for TBI, capable of improving diagnostic accuracy and clinical decision making beyond current practice standards. We performed a systematic review and meta-analysis to comprehensively and critically evaluate the existing body of evidence for the use of blood protein biomarkers (S100 calcium binding protein B [S100B], glial fibrillary acidic protein [GFAP], neuron specific enolase [NSE], ubiquitin C-terminal hydrolase-L1 [UCH-L1]. tau, and neurofilament proteins) for diagnosis of intracranial lesions on CT following mild TBI. Effects of potential confounding factors and differential diagnostic performance of the included markers were explored. Further, appropriateness of study design, analysis, quality, and demonstration of clinical utility were assessed. Studies published up to October 2016 were identified through searches of MEDLINE^®, Embase, EBM Reviews, the Cochrane Library, World Health Organization (WHO), International Clinical Trials Registry Platform (ICTRP), and clinicaltrials.gov. Following screening of the identified articles, 26 were selected as relevant. We found that measurement of S100B can help informed decision making in the emergency department, possibly reducing resource use; however, there is insufficient evidence that any of the other markers is ready for clinical application. Our work pointed out serious problems in the design, analysis, and reporting of many of the studies, and identified substantial heterogeneity and research gaps. These findings emphasize the importance of methodologically rigorous studies focused on a biomarker's intended use, and defining standardized, validated, and reproducible approaches. The living nature of this systematic review, which will summarize key updated information as it becomes available, can inform and guide future implementation of biomarkers in the clinical arena.

Intérêt clinique des concentrations sériques de la protéine S100β dans l’évaluation des patients traumatisés crâniens

Les recommandations de la Société française de médecine d’urgence concernant la prise en charge des patients traumatisés crâniens légers ont été éditées en 2012, complétées par des recommandations sur la bonne utilisation du biomarqueur S100β deux ans plus tard. Grâce à son excellente valeur prédictive négative, la protéine S100β utilisée à travers des règles strictes de prescription a été définie comme une alternative solide à la tomodensitométrie. Cependant, plusieurs questions restent en suspens concernant le délai maximum de réalisation du prélèvement par rapport à l’heure du traumatisme, l’impact médicoéconomique, les variations en rapport avec l’âge du patient, l’impact des agents anticoagulants ou antiagrégants plaquettaires et l’utilité du dosage sérique de cette protéine dans d’autres cadres nosologiques.

Chronic Traumatic Encephalopathy: Is Latency in Symptom Onset Explained by Tau Propagation?

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy associated with repetitive mild brain trauma. CTE, previously termed "dementia pugilistica," has been identified in American football, ice hockey, baseball, rugby and soccer players, boxers, wrestlers, and military personnel exposed to blast and other traumatic brain injuries. There is often a long latency period between an individual's exposure to repetitive brain trauma and the clinical symptoms of CTE. The pathology of CTE is characterized by a progression from isolated focal perivascular hyperphosphorylated tau lesions in the cerebral cortex to a widespread tauopathy that involves diffuse cortical and medial temporal lobe regions. We hypothesize that the spread of tau from focal perivascular lesions to a widespread tauopathy occurs as a result of intraneuronal and intrasynaptic prion-like protein templating, as well as tau secretion and propagation along glymphatic and cerebrospinal fluid pathways.

An update on diagnostic and prognostic biomarkers for traumatic brain injury

INTRODUCTION

Traumatic brain injury (TBI) is a major worldwide neurological disorder of epidemic proportions. To date, there are still no FDA-approved therapies to treat any forms of TBI. Encouragingly, there are emerging data showing that biofluid-based TBI biomarker tests have the potential to diagnose the presence of TBI of different severities including concussion, and to predict outcome. Areas covered: The authors provide an update on the current knowledge of TBI biomarkers, including protein biomarkers for neuronal cell body injury (UCH-L1, NSE), astroglial injury (GFAP, S100B), neuronal cell death (αII-spectrin breakdown products), axonal injury (NF proteins), white matter injury (MBP), post-injury neurodegeneration (total Tau and phospho-Tau), post-injury autoimmune response (brain antigen-targeting autoantibodies), and other emerging non-protein biomarkers. The authors discuss biomarker evidence in TBI diagnosis, outcome prognosis and possible identification of post-TBI neurodegernative diseases (e.g. chronic traumatic encephalopathy and Alzheimer's disease), and as theranostic tools in pre-clinical and clinical settings. Expert commentary: A spectrum of biomarkers is now at or near the stage of formal clinical validation of their diagnostic and prognostic utilities in the management of TBI of varied severities including concussions. TBI biomarkers could serve as a theranostic tool in facilitating drug development and treatment monitoring.

The current state of biomarkers of mild traumatic brain injury

Mild traumatic brain injury (mTBI) is a common occurrence, with over 3 million cases reported every year in the United States. While research into the underlying pathophysiology is ongoing, there is an urgent need for better clinical guidelines that allow more consistent diagnosis of mTBI and ensure safe return-to-play timelines for athletes, nonathletes, and military personnel. The development of a suite of biomarkers that indicate the pathogenicity of mTBI could lead to clinically useful tools for establishing both diagnosis and prognosis. Here, we review the current evidence for mTBI biomarkers derived from investigations of the multifactorial pathology of mTBI. While the current literature lacks the scope and size for clarification of these biomarkers' clinical utility, early studies have identified some promising candidates.

Evaluation of the Roche® Elecsys and the Diasorin® Liaison S100 kits in the management of mild head injury in the emergency room

INTRODUCTION

The aim of this single-center prospective study is to compare two commercially available S100ß kits (the Roche® Elecsys and the Diasorin® Liaison S100 kits) in terms of analytical and clinical performances in a population admitted in the emergency room for mild traumatic brain injury (mTBI).

MATERIAL AND METHOD

110 patients were enrolled from September 2014 to May 2015. Blood sample draws were performed within 3h after head trauma and the study population was split into pediatric and adult subpopulations (>18years of age).

RESULTS

Although both kits correlated well, we observed a significant difference in terms of S100ß levels (P value<0.05) in both subpopulations. In the pediatric subpopulation, both kits showed elevated S100ß levels for the only patient (3.5%) who displayed abnormal findings on a CT-scan. However, we observed a poor agreement between both kits (Cohen's kappa=0.345, P value=0.077). In the adult subpopulation, a total of 10 patients (12.2%) had abnormal head computed tomography scans. Using the Roche® (cut off=0.1μg/L) and the Diasorin® (cut off=0.15μg/L) S100ß kits, brain injuries were detected with a sensitivity of 100% (95% CI: 65-100%) and 100% (95% CI: 63-100%) and a specificity of 15.28% (95% CI: 7.9-25.7%) and 24.64% (95% CI: 15-36.5) respectively. Finally, a moderate agreement was concluded between both kits (Cohen's kappa=0.569, P value=0.001).

CONCLUSION

Although a good correlation could be found between both kits, emergency physicians should be aware of discrepancies observed between both methods, making those immunoassays not interchangeable. Furthermore, more studies are still needed to validate cut off used according to technique and to age, especially in the population below the age of 2years.

Could serum S100B be a predictor of neuronal damage and clinical poor outcomes associated with the use of synthetic cannabinoids? S100B to predict neuronal damage of SC in the ED

AIM

This study aims to evaluate the serum S100B levels to predict neuronal damage and poor clinical outcomes associated with the use of synthetic cannabinoids.

METHOD

Thirty patients identified as synthetic cannabinoid users and 30 healthy controls were included in the study. S100B levels were compared between healthy controls and synthetic cannabinoid users. The following were considered to be composite outcomes: the need for endotracheal intubation, incidence of seizures, the need for intensive care unit admission, and in-hospital mortality. Clinical and laboratory findings associated with composite clinical outcomes were examined.

RESULTS

The mean S100B level was 19.3 (95% CI: 17.7 to 21.4) pg/mL in patients who use synthetic cannabinoid, and 15.9 (95% CI: 15 to 16.9) pg/mL in the controls; mean df: -3.6 (95% CI: -5.6 to -1.6). In patients with and without composite clinical outcomes, the mean S100B level measured 24.5 (95% CI: 21.2 to 27.9) pg/mL and 17.4 (95% CI: 15.8 to 18.4) pg/mL, respectively; mean df: -7.4 (95% CI: -10.2 to -4.6). With the cut-off value for S100B set at 20pg/mL based on the highest sensitivity, the sensitivity, specificity, PPV, and NPV for S100B were 89.9%, 52.0%, 44.4%, and 91.9%, respectively; odds ratio: 13.2, 95% CI (2.1 to 28.1).

CONCLUSION

Our data suggest that serum S100B levels are elevated in patients using synthetic cannabinoids. These results show that S100B can help clinicians stratify risk or may have a role in excluding those with neuronal damage.

Validation of the sensitivity of the National Emergency X-Radiography Utilization Study (NEXUS) Head computed tomographic (CT) decision instrument for selective imaging of blunt head injury patients: An observational study

BACKGROUND

Clinicians, afraid of missing intracranial injuries, liberally obtain computed tomographic (CT) head imaging in blunt trauma patients. Prior work suggests that clinical criteria (National Emergency X-Radiography Utilization Study [NEXUS] Head CT decision instrument [DI]) can reliably identify patients with important injuries, while excluding injury, and the need for imaging in many patients. Validating this DI requires confirmation of the hypothesis that the lower 95% confidence limit for its sensitivity in detecting serious injury exceeds 99.0%. A secondary goal of the study was to complete an independent validation and comparison of the Canadian and NEXUS Head CT rules among the subgroup of patients meeting the inclusion and exclusion criteria.

METHODS AND FINDINGS

We conducted a prospective observational study of the NEXUS Head CT DI in 4 hospital emergency departments between April 2006 and December 2015. Implementation of the rule requires that patients satisfy 8 criteria to achieve "low-risk" classification. Patients are excluded from "low-risk" classification and assigned "high-risk" status if they fail to meet 1 or more criteria. We examined the instrument's performance in assigning "high-risk" status to patients requiring neurosurgical intervention among a cohort of 11,770 blunt head injury patients. The NEXUS Head CT DI assigned high-risk status to 420 of 420 patients requiring neurosurgical intervention (sensitivity, 100.0% [95% confidence interval [CI]: 99.1%-100.0%]). The instrument assigned low-risk status to 2,823 of 11,350 patients who did not require neurosurgical intervention (specificity, 24.9% [95% CI: 24.1%-25.7%]). None of the 2,823 low-risk patients required neurosurgical intervention (negative predictive value [NPV], 100.0% [95% CI: 99.9%-100.0%]). The DI assigned high-risk status to 759 of 767 patients with significant intracranial injuries (sensitivity, 99.0% [95% CI: 98.0%-99.6%]). The instrument assigned low-risk status to 2,815 of 11,003 patients who did not have significant injuries (specificity, 25.6% [95% CI: 24.8%-26.4%]). Significant injuries were absent in 2,815 of the 2,823 patients assigned low-risk status (NPV, 99.7% [95% CI: 99.4%-99.9%]). Of our patients, 7,759 (65.9%) met the inclusion and exclusion criteria of the Canadian Head CT rule, including 111 patients (1.43%) who required neurosurgical intervention and 306 (3.94%) who had significant intracranial injuries. In our study, the Canadian criteria for neurosurgical intervention identified 108 of 111 patients requiring neurosurgical intervention to yield a sensitivity of 97.3% (95% CI: 92.3%-99.4%) and exhibited a specificity of 58.8% (95% CI: 57.7%-59.9%). The NEXUS rule, when applied to this same cohort, identified all 111 patients requiring neurosurgical intervention, yielding a sensitivity of 100% (95% CI: 96.7%-100.0%) with a specificity of 32.6% (95% CI: 31.5%-33.6%). Our study found that the Canadian medium-risk factors identified 301 of 306 patients with significant injuries (sensitivity = 98.4%; 95% CI: 96.2%-99.5%), while the NEXUS rule identified 299 of these patients (sensitivity = 97.7%; 95% CI: 95.3%-99.1%). In our study, the Canadian medium-risk rule exhibited a specificity of 12.3% (95% CI: 11.6%-13.1%), while the NEXUS rule exhibited a specificity of 33.3% (95% CI: 32.3%-34.4%). Limitations of the study may arise from application of the rule by different clinicians in different environments. Clinicians may vary in their interpretation and application of the instrument's criteria and risk assignment and may also vary in deciding which patients require intervention. The instrument's specificity is also subject to spectrum bias and may change with variations in the proportion of "low-risk" patients seen in other centers.

CONCLUSIONS

The NEXUS Head CT DI reliably identifies blunt trauma patients who require head CT imaging and could significantly reduce the use of CT imaging.

[Mild head injuries in the elderly]

In the elderly, particularly those over 80 years old, head injuries often occur as a result of falls. The majority suffer from mild head injury. After clarification of the initial symptoms in these patients, the main aim is to recognize or exclude intracranial injuries (bleeding). Demonstration of intracranial bleeding is possible with cranial computed tomography (CCT), which in contrast to magnetic resonance imaging (MRI) can be quickly carried out in most cases; however, most patients with mild head injury show no intracranial bleeding. The performance of CCT and the often necessary hospital admission place a severe physical and psychological burden on the elderly. The plasma parameter S100B, combined with the clinical findings, is a valuable instrument for decision making in the management of elderly patients with mild head injury.