Early CSF and Serum S100B Concentrations for Outcome Prediction in Traumatic Brain Injury and Subarachnoid Hemorrhage

The serum biomarkers NSE and S100B predict intracranial complications and in-hospital survival in patients undergoing veno-venous ECMO

Neurological complications in patients undergoing veno-venous extracorporeal membrane oxygenation (V-V ECMO) are challenging, with new intracranial pathologies posing a grave risk. We aimed to evaluate the utility of neuron-specific enolase (NSE) and S100B biomarkers for predicting outcomes in new-onset intracranial pathology during V-V ECMO. A retrospective analysis spanning 2013-2021 at a German university hospital was conducted. Cases with electronically available data on NSE and S100B serum levels, new intracranial pathologies (intracerebral hemorrhage [ICH], subarachnoid hemorrhage [SAH], cerebral ischemia, hypoxic-ischemic encephalopathy [HIE]), and survival during or after V-V ECMO were screened. The primary objective was to assess the prognostic value of NSE and S100B for in-hospital survival during V-V ECMO. Secondary objectives included analyzing clinical characteristics, outcome parameters, and biomarker distribution in V-V ECMO patients. Additionally, the prognostic value of NSE and S100B for in-hospital death and occurrence of intracranial pathology was calculated. Among 744 ECMO recipients, 426 underwent V-V ECMO. No significant differences in disease severity or organ failure scores were observed between groups, except for SAPS at discharge, which was higher in patients with new intracranial pathologies. Patients with new intracranial pathologies had lower median survival and higher in-hospital mortality. Weaning success from ECMO was also significantly reduced in these patients. Cut-off values of 58.4 µg/lfor NSE and 1.52 µg/l for S100B were associated with detrimental outcomes, characterized by significantly reduced median survival. A significant difference in maximum serum NSE concentration was found between patients with and without new intracranial pathology. All screened cases with new intracranial pathology had an unfavorable neurological outcome (modified Rankin Score [mRS] > 3) at discharge, with a higher proportion having an mRS of 6 in the high NSE group. The emergence of intracranial pathology during V-V ECMO significantly increases the risk of death. Changes in NSE and S100B levels serve as valuable follow-up parameters for predicting new intracranial pathology and survival during V-V ECMO therapy.

The association between serum S100β levels and prognosis in acute stroke patients after intravenous thrombolysis: a multicenter prospective cohort study

BACKGROUND

S100β is a biomarker of astroglial damage, the level of which is significantly increased following brain injury. However, the characteristics of S100β and its association with prognosis in patients with acute ischemic stroke following intravenous thrombolysis (IVT) remain unclear.

METHODS

Patients in this multicenter prospective cohort study were prospectively and consecutively recruited from 16 centers. Serum S100β levels were measured 24 h after IVT. National Institutes of Health Stroke Scale (NIHSS) and hemorrhagic transformation (HT) were measured simultaneously. NIHSS at 7 days after stroke, final infarct volume, and modified Rankin Scale (mRS) scores at 90 days were also collected. An mRS score ≥ 2 at 90 days was defined as an unfavorable outcome.

RESULTS

A total of 1072 patients were included in the analysis. The highest S100β levels (> 0.20 ng/mL) correlated independently with HT and higher NIHSS at 24 h, higher NIHSS at 7 days, larger final infarct volume, and unfavorable outcome at 3 months. The patients were divided into two groups based on dominant and non-dominant stroke hemispheres. The highest S100β level was similarly associated with the infarct volume in patients with stroke in either hemisphere (dominant: β 36.853, 95% confidence interval (CI) 22.659-51.048, P < 0.001; non-dominant: β 23.645, 95% CI 10.774-36.516, P = 0.007). However, serum S100β levels at 24 h were more strongly associated with NIHSS scores at 24 h and 3-month unfavorable outcome in patients with dominant hemisphere stroke (NIHSS: β 3.470, 95% CI 2.392-4.548, P < 0.001; 3-month outcome: odds ratio (OR) 5.436, 95% CI 2.936-10.064, P < 0.001) than in those with non-dominant hemisphere stroke (NIHSS: β 0.326, 95% CI  - 0.735-1.387, P = 0.547; 3-month outcome: OR 0.882, 95% CI 0.538-1.445, P = 0.619). The association of S100β levels and HT was not significant in either stroke lateralization group.

CONCLUSIONS

Serum S100β levels 24 h after IVT were independently associated with HT, infarct volume, and prognosis in patients with IVT, which suggests the application value of serum S100β in judging the degree of disease and predicting prognosis.

Blood Biomarkers for the Management of Mild Traumatic Brain Injury in Clinical Practice

BACKGROUND

Despite the use of validated guidelines in the management of mild traumatic brain injury (mTBI), processes to limit unnecessary brain scans are still not sufficient and need to be improved. The use of blood biomarkers represents a relevant adjunct to identify patients at risk for intracranial injury requiring computed tomography (CT) scan.

CONTENT

Biomarkers currently recommended in the management of mTBI in adults and children are discussed in this review. Protein S100 beta (S100B) is the best-documented blood biomarker due to its validation in large observational and interventional studies. Glial fibrillary acidic protein (GFAP) and ubiquitin carboxyterminal hydrolase L-1 (UCH-L1) have also recently demonstrated their usefulness in patients with mTBI. Preanalytical, analytical, and postanalytical performance are presented to aid in their interpretation in clinical practice. Finally, new perspectives on biomarkers and mTBI are discussed.

SUMMARY

In adults, the inclusion of S100B in Scandinavian and French guidelines has reduced the need for CT scans by at least 30%. S100B has significant potential as a diagnostic biomarker, but limitations include its rapid half-life, which requires blood collection within 3 h of trauma, and its lack of neurospecificity. In 2018, the FDA approved the use of combined determination of GFAP and UCH-L1 to aid in the assessment of mTBI. Since 2022, new French guidelines also recommend the determination of GFAP and UCH-L1 in order to target a larger number of patients (sampling within 12 h post-injury) and optimize the reduction of CT scans. In the future, new cut-offs related to age and promising new biomarkers are expected for both diagnostic and prognostic applications.

Proteomic profile and predictive markers of outcome in patients with subarachnoid hemorrhage

BACKGROUND

The molecular mechanisms underlying development of posthemorrhagic hydrocephalus (PHH) following subarachnoid hemorrhage (SAH) remain incompletely understood. Consequently, treatment strategies tailored towards the individual patient remain limited. This study aimed to identify proteomic cerebrospinal fluid (CSF) biomarkers capable of predicting shunt dependency and functional outcome in patients with SAH in order to improve informed clinical decision making.

METHODS

Ventricular CSF samples were collected twice from 23 patients with SAH who required external ventricular drain (EVD) insertion (12 patients with successful EVD weaning, 11 patients in need of permanent CSF shunting due to development of PHH). The paired CSF samples were collected acutely after ictus and later upon EVD removal. Cisternal CSF samples were collected from 10 healthy control subjects undergoing vascular clipping of an unruptured aneurysm. All CSF samples were subjected to mass spectrometry-based proteomics analysis. Proteomic biomarkers were quantified using area under the curve (AUC) estimates from a receiver operating curve (ROC).

RESULTS

CSF from patients with SAH displayed a distinct proteomic profile in comparison to that of healthy control subjects. The CSF collected acutely after ictus from patients with SAH was moreover distinct from that collected weeks later but appeared similar in the weaned and shunted patient groups. Sixteen unique proteins were identified as potential predictors of shunt dependency, while three proteins were identified as potential predictors of functional outcome assessed six months after ictus with the modified Rankin Scale.

CONCLUSIONS

We here identified several potential proteomic biomarkers in CSF from patients with SAH capable of predicting (i) shunt dependency and thus development of PHH and (ii) the functional outcome assessed six months after ictus. These proteomic biomarkers may have the potential to aid clinical decision making by predicting shunt dependency and functional outcome following SAH.

Astroglial S100B Secretion Is Mediated by Ca2+ Mobilization from Endoplasmic Reticulum: A Study Using Forskolin and DMSO as Secretagogues

S100B, a homodimeric Ca2+-binding protein, is produced and secreted by astrocytes, and its extracellular levels have been used as a glial marker in brain damage and neurodegenerative and psychiatric diseases; however, its mechanism of secretion is elusive. We used primary astrocyte cultures and calcium measurements from real-time fluorescence microscopy to investigate the role of intracellular calcium in S100B secretion. In addition, the dimethyl sulfoxide (DMSO) effect on S100B was investigated in vitro and in vivo using Wistar rats. We found that DMSO, a widely used vehicle in biological assays, is a powerful S100B secretagogue, which caused a biphasic response of Ca2+ mobilization. Our data show that astroglial S100B secretion is triggered by the increase in intracellular Ca2+ and indicate that this increase is due to Ca2+ mobilization from the endoplasmic reticulum. Also, blocking plasma membrane Ca2+ channels involved in the Ca2+ replenishment of internal stores decreased S100B secretion. The DMSO-induced S100B secretion was confirmed in vivo and in ex vivo hippocampal slices. Our data support a nonclassic vesicular export of S100B modulated by Ca2+, and the results might contribute to understanding the mechanism underlying the astroglial release of S100B.

Serum and cerebrospinal fluid brain damage markers neurofilament light and glial fibrillary acidic protein correlate with tick-borne encephalitis disease severity-a multicentre study on Lithuanian and Swedish patients

BACKGROUND AND PURPOSE

Our aim was to examine the correlation between biomarkers of neuronal and glial cell damage and severity of disease in patients with tick-borne encephalitis.

METHODS

One hundred and fifteen patients with tick-borne encephalitis diagnosed in Lithuania and Sweden were prospectively included, and cerebrospinal fluid (CSF) and serum samples were obtained shortly after hospitalization. Using pre-defined criteria, cases were classified as mild, moderate or severe tick-borne encephalitis. Additionally, the presence of spinal nerve paralysis (myelitis) and/or cranial nerve affection were noted. Concentrations of the brain cell biomarkers glial fibrillary acidic protein (GFAP), YKL-40, S100B, neurogranin, neurofilament light (NfL) and tau were analysed in CSF and, in addition, NfL, GFAP and S100B levels were measured in serum. The Jonckheere-Terpstra test was used for group comparisons of continuous variables and Spearman's partial correlation test was used to adjust for age.

RESULTS

Cerebrospinal fluid and serum concentrations of GFAP and NfL correlated with disease severity, independent of age, and with the presence of nerve paralysis. The markers neurogranin, YKL-40, tau and S100B in CSF and S100B in serum were detected, but their concentrations did not correlate with disease severity.

CONCLUSIONS

Neuronal cell damage and astroglial cell activation with increased NfL and GFAP in CSF and serum were associated with a more severe disease, independent of age. Increased GFAP and NfL concentrations in CSF and NfL in serum were also indicative of spinal and/or cranial nerve damage. NfL and GFAP are promising prognostic biomarkers in tick-borne encephalitis, and future studies should focus on determining the association between these biomarkers and long-term sequelae.

Mini review: Current status and perspective of S100B protein as a biomarker in daily clinical practice for diagnosis and prognosticating of clinical outcome in patients with neurological diseases with focus on acute brain injury

Prognosticating the clinical outcome of neurological diseases is essential to guide treatment and facilitate decision-making. It usually depends on clinical and radiological findings. Biomarkers have been suggested to support this process, as they are deemed objective measures and can express the extent of tissue damage or reflect the degree of inflammation. Some of them are specific, and some are not. Few of them, however, reached the stage of daily application in clinical practice. This mini review covers available applications of the S100B protein in prognosticating clinical outcome in patients with various neurological disorders, particularly in those with traumatic brain injury, spontaneous subarachnoid hemorrhage and ischemic stroke. The aim is to provide an understandable picture of the clinical use of the S100B protein and give a brief overview of the current limitations that require future solutions.

Systematic Review of the Diagnostic and Clinical Utility of Salivary microRNAs in Traumatic Brain Injury (TBI)

Research in traumatic brain injury (TBI) is an urgent priority, as there are currently no TBI biomarkers to assess the severity of injury, to predict outcomes, and to monitor recovery. Small non-coding RNAs (sncRNAs) including microRNAs can be measured in saliva following TBI and have been investigated as potential diagnostic markers. The aim of this systematic review was to investigate the diagnostic or prognostic ability of microRNAs extracted from saliva in human subjects. PubMed, Embase, Scopus, PsycINFO and Web of Science were searched for studies that examined the association of saliva microRNAs in TBI. Original studies of any design involving diagnostic capacity of salivary microRNAs for TBI were selected for data extraction. Nine studies met inclusion criteria, with a heterogeneous population involving athletes and hospital patients, children and adults. The studies identified a total of 188 differentially expressed microRNAs, with 30 detected in multiple studies. MicroRNAs in multiple studies involved expression change bidirectionality. The study design and methods involved significant heterogeneity that precluded meta-analysis. Early data indicates salivary microRNAs may assist with TBI diagnosis. Further research with consistent methods and larger patient populations is required to evaluate the diagnostic and prognostic potential of saliva microRNAs.

The role of the astrocyte in subarachnoid hemorrhage and its therapeutic implications

Subarachnoid hemorrhage (SAH) is an important public health concern with high morbidity and mortality worldwide. SAH induces cell death, blood−brain barrier (BBB) damage, brain edema and oxidative stress. As the most abundant cell type in the central nervous system, astrocytes play an essential role in brain damage and recovery following SAH. This review describes astrocyte activation and polarization after SAH. Astrocytes mediate BBB disruption, glymphatic–lymphatic system dysfunction, oxidative stress, and cell death after SAH. Furthermore, astrocytes engage in abundant crosstalk with other brain cells, such as endothelial cells, neurons, pericytes, microglia and monocytes, after SAH. In addition, astrocytes also exert protective functions in SAH. Finally, we summarize evidence regarding therapeutic approaches aimed at modulating astrocyte function following SAH, which could provide some new leads for future translational therapy to alleviate damage after SAH.

Prediction and Risk Assessment Models for Subarachnoid Hemorrhage: A Systematic Review on Case Studies

Subarachnoid hemorrhage (SAH) is one of the major health issues known to society and has a higher mortality rate. The clinical factors with computed tomography (CT), magnetic resonance image (MRI), and electroencephalography (EEG) data were used to evaluate the performance of the developed method. In this paper, various methods such as statistical analysis, logistic regression, machine learning, and deep learning methods were used in the prediction and detection of SAH which are reviewed. The advantages and limitations of SAH prediction and risk assessment methods are also being reviewed. Most of the existing methods were evaluated on the collected dataset for the SAH prediction. In some researches, deep learning methods were applied, which resulted in higher performance in the prediction process. EEG data were applied in the existing methods for the prediction process, and these methods demonstrated higher performance. However, the existing methods have the limitations of overfitting problems, imbalance data problems, and lower efficiency in feature analysis. The artificial neural network (ANN) and support vector machine (SVM) methods have been applied for the prediction process, and considerably higher performance is achieved by using this method.

The management of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a rare event affecting relatively young patients therefore leading to a high social impact. The management of SAH follows a biphasic course with early brain injuries in the first 72 hours followed by a phase at risk of secondary deterioration due to delayed cerebral ischemia (DCI) in 20 to 30% patients. Cerebral infarction from DCI is the most preventable cause of mortality and morbidity after SAH. DCI prevention, early detection and treatment is therefore advocated. Formerly limited to the occurrence of vasospasm, DCI is now associated with multiple pathophysiological processes involving for instance the macrocirculation, the microcirculation, neurovascular units, and inflammation. Therefore, the therapeutic targets and management strategies are also evolving and are not only focused on proximal vasospasm. In this review, we describe the current knowledge of DCI pathophysiology. We then discuss the diagnosis strategies that may guide physicians at the bedside with a multimodal approach in the unconscious patient. We will present the prevention strategies that have proven efficient as well as future targets and present the therapeutic approach that is currently being developed when a DCI occurs.

The Clinical Use of Serum Biomarkers in Traumatic Brain Injury: A Systematic Review Stratified by Injury Severity

BACKGROUND

Serum biomarkers have gained significant popularity as an adjunctive measure in the evaluation and prognostication of traumatic brain injury (TBI). However, a concise and clinically oriented report of the major markers in function of TBI severity is lacking. This systematic review aims to report current data on the diagnostic and prognostic utility of blood-based biomarkers across the spectrum of TBI.

METHODS

A literature search of the PubMed/Medline electronic database was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We excluded systematic reviews and meta-analyses that did not provide novel data. The American College of Cardiology/American Heart Association criteria were used to assess levels of evidence.

RESULTS

An initial 1463 studies were identified. In total, 115 full-text articles reporting on 94 distinct biomarkers met the inclusion criteria. Glasgow Coma Scale scores, computed tomography/magnetic resonance imaging abnormalities, and injury severity scores were the most used clinical diagnostic variables. Glasgow Outcome Scores and 1-, 3-, and 6-month mortality were the most used clinical prognostic variables. Several biomarkers significantly correlated with these variables and had statistically significant different levels in TBI subjects when compared with healthy, orthopedic, and polytrauma controls. The biomarkers also displayed significant variability across mild, moderate, and severe TBI categories, as well as in concussion cases.

CONCLUSIONS

This review summarizes existing high-quality evidence that supports the use of severity-specific biomarkers in the diagnostic and prognostic evaluation of TBI. These data can be used as a launching platform for the validation of upcoming clinical studies.

Systematic Review of Serum Biomarkers in Traumatic Brain Injury

Traumatic brain injury (TBI) is responsible for the majority of trauma-related deaths and is a leading cause of disability. It is characterized by an inflammatory process involved in the progression of secondary brain injury. TBI is measured by the Glasgow Coma Scale (GCS) with scores ranging from 15-3, demonstrating mild to severe brain injury. Apart from this clinical assessment of TBI, compendiums of literature have been published on TBI-related serum markers.Herein we create a comprehensive appraisal of the most prominent serum biomarkers used in the assessment and care of TBI.The PubMed, Scopus, Cochrane, and Web of Science databases were queried with the terms “biomarker” and “traumatic brain injury” as search terms with only full-text, English articles within the past 10 years selected. Non-human studies were excluded, and only adult patients fell within the purview of this analysis. A total of 528 articles were analyzed in the initial search with 289 selected for screening. A further 152 were excluded for primary screening. Of the remaining 137, 54 were included in the final analysis. Serum biomarkers were listed into the following broad categories for ease of discussion: immune markers and markers of inflammation, hormones as biomarkers, coagulation and vasculature, genetic polymorphisms, antioxidants and oxidative stress, apoptosis and degradation pathways, and protein markers. Glial fibrillary acidic protein(GFAP), S100, and neurons specific enolase (NSE) were the most prominent and frequently cited markers. Amongst these three, no single serum biomarker demonstrated neither superior sensitivity nor specificity compared to the other two, therefore noninvasive panels should incorporate these three serum biomarkers to retain sensitivity and maximize specificity for TBI.

A blood biomarker and clinical correlation cohort study protocol to diagnose sports-related concussion and monitor recovery in elite rugby

Introduction

In professional rugby, sports-related concussion (SRC) remains the most frequent time loss injury. Therefore, accurately diagnosing SRC and monitoring player recovery, through a multi-modal assessment process, is critical to SRC management. In this protocol study, we aim to assess SRC over multiple time points post-injury to determine the value of multi-modal assessments to monitor player recovery. This is of significance to minimise premature return-to-play and, ultimately, to reduce the long-term effects associated with SRC. The study will also establish the logistics of implementing such a study in a professional setting to monitor a player's SRC recovery.

Methods and analysis

All players from the participating professional rugby club within the Irish Rugby Football Union are invited to participate in the current study. Player assessment includes head injury assessment (HIA), neuropsychometric assessment (ImPACT), targeted biomarker analysis and untargeted biomarker analysis. Baseline HIA, ImPACT, and blood draws are performed prior to the start of playing season. During the baseline tests, player's complete consent forms and an SRC history questionnaire. Subsequently, any participant that enters the HIA process over the playing season due to a suspected SRC will be clinically assessed (HIA and ImPACT) and their blood will be drawn within 3 days of injury, 6 days post-injury, and 13 days post-injury.

Ethics and dissemination

Ethical approval was attained from the Science and Engineering Research Ethics Committee, University of Limerick (Approval Code: 2018_06_11_S&E). On completion of the study, further manuscripts will be published to present the results of the tests and their ability to measure player recovery from SRC.

Trial registration number

NCT04485494.

Association of cerebrospinal fluid protein biomarkers with outcomes in patients with traumatic and non-traumatic acute brain injury: systematic review of the literature

BACKGROUND

Acute brain injuries are associated with high mortality rates and poor long-term functional outcomes. Measurement of cerebrospinal fluid (CSF) biomarkers in patients with acute brain injuries may help elucidate some of the pathophysiological pathways involved in the prognosis of these patients.

METHODS

We performed a systematic search and descriptive review using the MEDLINE database and the PubMed interface from inception up to June 29, 2021, to retrieve observational studies in which the relationship between CSF concentrations of protein biomarkers and neurological outcomes was reported in patients with acute brain injury [traumatic brain injury, subarachnoid hemorrhage, acute ischemic stroke, status epilepticus or post-cardiac arrest]. We classified the studies according to whether or not biomarker concentrations were associated with neurological outcomes. The methodological quality of the studies was evaluated using the Newcastle-Ottawa quality assessment scale.

RESULTS

Of the 39 studies that met our criteria, 30 reported that the biomarker concentration was associated with neurological outcome and 9 reported no association. In TBI, increased extracellular concentrations of biomarkers related to neuronal cytoskeletal disruption, apoptosis and inflammation were associated with the severity of acute brain injury, early mortality and worse long-term functional outcome. Reduced concentrations of protein biomarkers related to impaired redox function were associated with increased risk of neurological deficit. In non-traumatic acute brain injury, concentrations of CSF protein biomarkers related to dysregulated inflammation and apoptosis were associated with a greater risk of vasospasm and a larger volume of brain ischemia. There was a high risk of bias across the studies.

CONCLUSION

In patients with acute brain injury, altered CSF concentrations of protein biomarkers related to cytoskeletal damage, inflammation, apoptosis and oxidative stress may be predictive of worse neurological outcomes.

Serum biomarkers and cerebral autoregulation as early warnings of delayed cerebral ischemia risk in patients after aneurysmal subarachnoid haemorrhage

BACKGROUND

Identifying patients at risk of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid haemorrhage (aSAH) remains challenging. This study aimed to evaluate the concentration of serum biomarkers along with cerebral autoregulation impairment on DCI.

METHODS

55 patients suffering from aSAH were enrolled in the study. Serum S100protein B (S100B) was tested both on the day of admission and over three consecutive days following the occurrence of aSAH. Cerebral autoregulation was assessed using a tissue oxygenation index (TOxa) based on near-infrared spectroscopy.

RESULTS

Changes in serum S100B levels interacted with DCI status (presence vs. absence): F = 3.84, p = 0.016. Patients with DCI had higher S100B concentration level on day 3 than those without DCI (3.54 ± 0.50 ng/ml vs. 0.58 ± 0.43 ng/ml, p = 0.001). S100B concentration on day 3 following aSAH predicted DCI (AUC = 0.77, p = 0.006). Raised level of serum S100B on day 3 was related with higher TOxa, thus with impaired cerebral autoregulation (r_S = 0.52,p = 0.031). Multivariate logistic regression analysis showed thatimpaired cerebral autoregulation andelevatedS100B concentration on day 3 increasethe likelihood of DCI.

CONCLUSIONS

Tracking changes in the serum biomarkers concentration along with monitoring of cerebral autoregulation, may play a role in early detection of patients at risk of DCI after aSAH. These results need to be validated in larger prospective cohorts.

DAMPs and RAGE Pathophysiology at the Acute Phase of Brain Injury: An Overview

Early or primary injury due to brain aggression, such as mechanical trauma, hemorrhage or is-chemia, triggers the release of damage-associated molecular patterns (DAMPs) in the extracellular space. Some DAMPs, such as S100B, participate in the regulation of cell growth and survival but may also trigger cellular damage as their concentration increases in the extracellular space. When DAMPs bind to pattern-recognition receptors, such as the receptor of advanced glycation end-products (RAGE), they lead to non-infectious inflammation that will contribute to necrotic cell clearance but may also worsen brain injury. In this narrative review, we describe the role and ki-netics of DAMPs and RAGE at the acute phase of brain injury. We searched the MEDLINE database for “DAMPs” or “RAGE” or “S100B” and “traumatic brain injury” or “subarachnoid hemorrhage” or “stroke”. We selected original articles reporting data on acute brain injury pathophysiology, from which we describe DAMPs release and clearance upon acute brain injury, and the implication of RAGE in the development of brain injury. We will also discuss the clinical strategies that emerge from this overview in terms of biomarkers and therapeutic perspectives

Soluble receptor for advanced glycation end products as a biomarker of symptomatic vasospasm in subarachnoid hemorrhage

OBJECTIVE

The receptor for advanced glycation end products (RAGE) is a membrane protein associated with the induction of oxidative stress and inflammation in several pathological conditions. Previous studies have demonstrated that soluble RAGE (sRAGE) acts as a decoy for RAGE and protects cells against RAGE-mediated injury. The authors and other groups have reported that the expression of RAGE increases after brain ischemia and subarachnoid hemorrhage (SAH), and deletion of RAGE or overexpression of sRAGE improves neuronal survival. It has also been demonstrated that the plasma sRAGE level could be a predictor of the outcome after ischemic stroke. This study aimed to evaluate plasma sRAGE as a biomarker for symptomatic vasospasm (SVS) in SAH patients, as well as a rat model.

METHODS

The authors measured and compared plasma sRAGE levels in 27 SAH patients (7 with SVS and 20 without SVS) from day 5 to day 14 post-SAH. They also examined plasma sRAGE levels and expression of RAGE and heme oxygenase-1 (HO-1) in a rat SAH model.

RESULTS

The relative plasma sRAGE levels were significantly lower in the SVS group than in the non-SVS group of patients. A cut-off value of 0.84 for predicting SVS was considered to be appropriate for the relative plasma sRAGE levels on day 7 versus day 5. In the rat SAH model, plasma sRAGE levels were significantly lower than those in sham-treated rats, and the expressions of RAGE and HO-1 were enhanced in the SAH group compared with the non-SAH group.

CONCLUSIONS

Plasma sRAGE levels can be used as a potential biomarker for predicting SVS after SAH.

Brain-Specific Biomarkers as Mortality Predictors after Aneurysmal Subarachnoid Haemorrhage

Aneurysmal subarachnoid haemorrhage (aSAH) is a serious condition with a high mortality and high permanent disability rate for those who survive the initial haemorrhage. The purpose of this study was to investigate markers specific to the central nervous system as potential in-hospital mortality predictors after aSAH. In patients with an external ventricular drain, enolase, S100B, and GFAP levels were measured in the blood and cerebrospinal fluid (CSF) on days 1, 2, and 3 after aSAH. Compared to survivors, non-survivors showed a significantly higher peak of S100B and enolase levels in the blood (S100B: 5.7 vs. 1.5 ng/mL, p = 0.031; enolase: 6.1 vs. 1.4 ng/mL, p = 0.011) and the CSF (S100B: 18.3 vs. 0.9 ng/mL, p = 0.042; enolase: 109.2 vs. 6.1 ng/mL, p = 0.015). Enolase showed the highest level of predictability at 1.8 ng/mL in the blood (AUC of 0.873) and 80.0 ng/mL in the CSF (AUC of 0.889). The predictive ability of S100B was also very good with a threshold of 5.7 ng/mL in the blood (AUC 0.825) and 4.5 ng/mL in the CSF (AUC 0.810). In conclusion, enolase and S100B, but not GFAP, might be suitable as biomarkers for the early prediction of in-hospital mortality after aSAH.

Association of Cerebrospinal Fluid S100B Protein with Core Biomarkers and Cognitive Deficits in Prodromal and Mild Alzheimer's Disease

BACKGROUND

Increased expression of the astroglial Ca2+-binding protein S100B has been observed in various neurodegenerative diseases and also seems to play a role in the unfolding of pathophysiological events at early stages of Alzheimer's disease (AD).

OBJECTIVE

To examine the association of cerebrospinal fluid (CSF) levels of S100B with 1) established CSF core biomarkers total tau (tau), hyperphosphorylated tau (p-tau), and amyloid β1-42 (Aβ1-42) as well as neuron-specific enolase (NSE) CSF levels and 2) cognition in early AD and mild cognitive impairment (MCI) due to AD (MCI-AD).

METHODS

Retrospective study assessing 49 pooled charts of Memory Clinic and inpatients diagnosed with AD (N = 26) and MCI-AD (N = 23) according to the National Institute of Aging and Alzheimer's Disease Association (NIA-AA) criteria. Neuropsychological testing was performed with the Consortium to Establish a Registry for AD (CERAD)-Plus battery.

RESULTS

CSF levels of S100B correlated with NSE, but not the other CSF parameters. Stepwise multiple linear regression, adjusted for age, sex, and educational level, revealed that only increased CSF S100B was independently associated with lower CERAD-Plus total and Mini-Mental Status Examination scores together with poorer performance in wordlist learning (delayed recall and overall performance). We found no independent associations with other CSF biomarkers or cognitive domains.

CONCLUSION

Our data suggest that CSF S100B may have a diagnostic value particularly at early stages of AD reflecting the significance of neuroinflammatory/astroglial processes. Thus, CSF S100B may complement the established array of available AD biomarkers to improve early stage diagnosis.

Biomarkers of Neurological Outcome After Aneurysmal Subarachnoid Hemorrhage as Early Predictors at Discharge from an Intensive Care Unit

Background

Subarachnoid bleeding is associated with brain injuries and ranges from almost negligible to acute and life threatening. The main objectives were to study changes in brain-specific biomarker levels in patients after an aneurysmal subarachnoid hemorrhage (aSAH) in relation to early clinical findings, severity scores, and intensive care unit (ICU) outcome. Analysis was done to identify specific biomarkers as predictors of a bad outcome in the acute treatment phase.

Methods

Analysis was performed for the proteins of neurofilament, neuron-specific enolase (NSE), microtubule-associated protein tau (MAPT), and for the proteins of glial cells, S100B, and glial fibrillary acidic protein (GFAP). Outcomes were assessed at discharge from the ICU and analyzed based on the grade in the Glasgow Outcome Scale (GOS). Patients were classified into two groups: with a good outcome (Group 1: GOS IV–V, n = 24) and with a bad outcome (Group 2: GOS I–III, n = 31). Blood samples were taken upon admission to the ICU and afterward daily for up to 6 days.

Results

In Group 1, the level of S100B (1.0, 0.9, 0.7, 2.0, 1.0, 0.3 ng/mL) and NSE (1.5, 2.0, 1.6, 1.2, 16.6, 2.2 ng/mL) was significantly lower than in Group 2 (S100B: 4.7, 4.8, 4.4, 4.5, 6.6, 6.8 ng/mL; NSE: 4.0, 4.1, 4.3, 3.8, 4.4, 2.5 1.1 ng/mL) on day 1–6, respectively. MAPT was significantly lower only on the first and second day (83.2 ± 25.1, 132.7 ± 88.1 pg/mL in Group 1 vs. 625.0 ± 250.7, 616.4 ± 391.6 pg/mL in Group 2). GFAP was elevated in both groups from day 1 to 6. In the ROC analysis, S100B showed the highest ability to predict bad ICU outcome of the four biomarkers measured on admission [area under the curve (AUC) 0.81; 95% CI 0.67–0.94, p < 0.001]. NSE and MAPT also had significant predictive value (AUC 0.71; 95% CI 0.54–0.87, p = 0.01; AUC 0.74; 95% CI 0.55–0.92, p = 0.01, respectively). A strong negative correlation between the GOS and S100B and the GOS and NSE was recorded on days 1–5, and between the GOS and MAPT on day 1.

Conclusion

Our findings provide evidence that brain biomarkers such as S100B, NSE, GFAP, and MAPT increase significantly in patients following aSAH. There is a direct relationship between the neurological outcome in the acute treatment phase and the levels of S100B, NSE, and MAPT. The detection of brain-specific biomarkers in conjunction with clinical data may constitute a valuable diagnostic and prognostic tool in the early phase of aSAH treatment.

Damage-associated molecular patterns in trauma

In 1994, the "danger model" argued that adaptive immune responses are driven rather by molecules released upon tissue damage than by the recognition of "strange" molecules. Thus, an alternative to the "self versus non-self recognition model" has been provided. The model, which suggests that the immune system discriminates dangerous from safe molecules, has established the basis for the future designation of damage-associated molecular patterns (DAMPs), a term that was coined by Walter G. Land, Seong, and Matzinger. The pathological importance of DAMPs is barely somewhere else evident as in the posttraumatic or post-surgical inflammation and regeneration. Since DAMPs have been identified to trigger specific immune responses and inflammation, which is not necessarily detrimental but also regenerative, it still remains difficult to describe their "friend or foe" role in the posttraumatic immunogenicity and healing process. DAMPs can be used as biomarkers to indicate and/or to monitor a disease or injury severity, but they also may serve as clinically applicable parameters for optimized indication of the timing for, i.e., secondary surgeries. While experimental studies allow the detection of these biomarkers on different levels including cellular, tissue, and circulatory milieu, this is not always easily transferable to the human situation. Thus, in this review, we focus on the recent literature dealing with the pathophysiological importance of DAMPs after traumatic injury. Since dysregulated inflammation in traumatized patients always implies disturbed resolution of inflammation, so-called model of suppressing/inhibiting inducible DAMPs (SAMPs) will be very briefly introduced. Thus, an update on this topic in the field of trauma will be provided.

Usefulness of serum glucose and potassium ratio as a predictor for 30-day death among patients with severe traumatic brain injury

BACKGROUND

Serum glucose and potassium ratio (GPR) was recently found to be related to outcome of aneurysmal subarachnoid hemorrhage. This retrospectively study was to investigate the association of serum GPR with mortality in severe traumatic brain injury (sTBI).

METHODS

Clinical data were retrospectively reviewed of isolated sTBI patients admitted within 12 h after trauma between January 2014 and January 2019. We analyzed relationships between admission serum GPR and post-traumatic 30-day mortality in addition to admission Glasgow coma scale (GCS) scores. Discriminative ability was evaluated using area under receiver operating characteristic curve (AUC).

RESULTS

A total of 146 patients, of whom 37 (25.3%) died within 30 days following trauma, were included. Admission serum GPR emerged as an independent predictor for 30-day mortality (odds ratio, 5.256; 95% confidence interval (CI), 1.111-14.856) and overall survival (hazard ratio, 4.822; 95% CI, 1.157-12.870), with an AUC of 0.777 (95% CI, 0.693-0.835), which was equivalent to that of GCS scores (AUC, 0.831; 95% CI, 0.760-0.888; P = 0.179). There was a significant correlation between admission serum GPR and GCS scores (r² = 0.293).

CONCLUSIONS

Serum GPR in cases of sTBI is substantially associated with trauma severity and 30-day mortality. Therefore, the potential value of serum GPR for predicting short-term mortality of sTBI patients is favorable.

Biospecimens and Molecular and Cellular Biomarkers in Aneurysmal Subarachnoid Hemorrhage Studies: Common Data Elements and Standard Reporting Recommendations

INTRODUCTION

Development of clinical biomarkers to guide therapy is an important unmet need in aneurysmal subarachnoid hemorrhage (SAH). A wide spectrum of plausible biomarkers has been reported for SAH, but none have been validated due to significant variabilities in study design, methodology, laboratory techniques, and outcome endpoints.

METHODS

A systematic review of SAH biomarkers was performed per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The panel's recommendations focused on harmonization of (1) target cellular and molecular biomarkers for future investigation in SAH, (2) standardization of best-practice procedures in biospecimen and biomarker studies, and (3) experimental method reporting requirements to facilitate meta-analyses and future validation of putative biomarkers.

RESULTS

No cellular or molecular biomarker has been validated for inclusion as "core" recommendation. Fifty-four studies met inclusion criteria and generated 33 supplemental and emerging biomarker targets. Core recommendations include best-practice protocols for biospecimen collection and handling as well as standardized reporting guidelines to capture the heterogeneity and variabilities in experimental methodologies and biomarker analyses platforms.

CONCLUSION

Significant variabilities in study design, methodology, laboratory techniques, and outcome endpoints exist in SAH biomarker studies and present significant barriers toward validation and translation of putative biomarkers to clinical use. Adaptation of common data elements, recommended biospecimen protocols, and reporting guidelines will reduce heterogeneity and facilitate future meta-analyses and development of validated clinical biomarkers in SAH.

Glial Fibrillary Acidic Protein (GFAP) Outperforms S100 Calcium-Binding Protein B (S100B) and Ubiquitin C-Terminal Hydrolase L1 (UCH-L1) as Predictor for Positive Computed Tomography of the Head in Trauma Subjects

OBJECTIVE

Traumatic brain injuries (TBIs) are largely underdiagnosed and may have persistent refractory consequences. Current assessments for acute TBI are limited to physical examination and imaging. Biomarkers such as glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase L1 (UCH-L1), and S100 calcium-binding protein B (S100B) have shown predictive value as indicators of TBI and potential screening tools.

METHODS

In total, 37 controls and 118 unique trauma subjects who received a clinically ordered head computed tomography (CT) in the emergency department of a level 1 trauma center were evaluated. Blood samples collected at 0-8 hours (initial) and 12-32 hours (delayed) postinjury were analyzed for GFAP, UCH-L1, and S100B concentrations. These were then compared in CT-negative and CT-positive subjects.

RESULTS

Median GFAP, UCH-L1, and S100B concentrations were greater in CT-positive subjects at both timepoints compared with CT-negative subjects. In addition, median UCH-L1 and S100B concentrations were lower at the delayed timepoint, whereas median GFAP concentrations were increased. As predictors of a positive CT of the head, GFAP outperformed UCH-L1 and S100B at both timepoints (initial: 0.89 sensitivity, 0.62 specificity; delayed: 0.94 sensitivity, 0.67 specificity). GFAP alone also outperformed all possible combinations of biomarkers.

CONCLUSIONS

GFAP, UCH-L1, and S100B demonstrated utility for rapid prediction of a CT-positive TBI within 0-8 hours of injury. GFAP exhibited the greatest predictive power at 12-32 hours. Furthermore, these results suggest that GFAP alone has greater utility for predicting a positive CT of the head than UCH-L1, S100B, or any combination of the 3.

Serial measurement of S100B and NSE in pediatric traumatic brain injury

PURPOSE

Increased serum biomakers, such as S100 calcium-binding protein B (S100B) and neuron-specific enolase (NSE), are associated with traumatic brain injury (TBI). The purpose of this study is to investigate the serum levels of S100B and NSE in pediatric TBI patients and to predict a clinical outcome.

METHODS

Peripheral venous blood was collected within 6 h of injury and at 1 week to measure S100B and NSE. The serum S100B and NSE levels were measured using commercially available enzyme-linked immunosorbent assay kits. The authors divided participants into two groups at admission: a favorable group (patients with Glasgow Coma Scale [GCS] scores of 10-15) and an unfavorable group (patients with GCS scores of less than 9). Both S100B and NSE levels were compared between the two groups at the time of admission and 1 week later.

RESULTS

Ten pediatric patients were enrolled (5 in the favorable group, 5 in the unfavorable group). The median serum S100B level of 134.21 pg/ml (range, 51.00-789.65 pg/ml) in patients with TBI at admission dropped to 41.49 pg/ml (range, 25.65-260.93 pg/ml) after 1 week, with significant differences between the traumatic event and 1 week later (p = 0.007). The median serum NSE level of 14.76 ng/ml (range, 6.48-21.23 ng/ml) in patients with TBI at admission was higher than that after 1 week (4.96 ng/ml, range, 3.01-31.21 ng/ml), with significant differences (p = 0.015). A significant difference was observed in S100B after 1 week between patients in the favorable and unfavorable groups (p = 0.047). One patient whose serum S100B and NSE levels were elevated 1 week after TBI eventually died.

CONCLUSIONS

Elevated serum S100B and NSE levels in pediatric TBI patients decreased 1 week after traumatic events. The serum S100B level 1 week after TBI was related to the severity of brain damage. These results indicated that serum S100B and NSE might play a role in predicting the prognosis and monitoring ongoing brain injury in pediatric TBI patients.

S100B Serum Level as a Mortality Predictor for Traumatic Brain Injury: A Meta-Analysis

BACKGROUND:

The pathogenesis of inflammatory neuronal cell damage will continue after traumatic brain injury in which contributed to subsequent mortality. Serum S100B levels were shown to be an early predictor of mortality due to traumatic brain injury.

AIM:

This Meta-Analysis will analyse the mean and diagnostic strength of serum S100B levels between survived and died subjects with head injuries based on the various follow-up times of nine studies.

METHODS:

We conducted a meta-anelysis in accordance with PRISMA guidelines and adhering to Cochrane Handbook for Systematic Review of Interventions. Literature search was conducted on March 16, 2018 from Medline and Scopus in the past 10 years, using various keywords related to S100, brain injury, and outcome. Duplicate journals were sorted out via EndNote. Included articles were as follows: original data from the group, clinical trials, case series, patients undergoing serum S100B levels with both short- and long-term follow-up mortality. Data were collected for mortality, serum S100B levels, and its diagnostic strength. All data were analyzed using Review Manager 5.3 (Cochrane, Denmark).

RESULTS:

The results of the meta-analysis showed a significant difference in S100B levels between survived and died subjects with head injuries on overall follow-up timeline (0.91, 95.9% CI 0.7-1.12, I2 = 98%, p < 0.001), during treatment (1.43, 95% CI 0.97 to 1.89, I2 = 98%, p < 0.001), or 6 months (0.19; 95%CI 0.1-0.29, I2 = 76%, p < 0.001) with an average threshold value that varies according to the study method used. The mean diagnostic strength was also promising to predict early mortality (sensitivity of 77.18% and 92.33%, specificity of 78.35% and 50.6%, respectively).

CONCLUSION:

S100B serum levels in the future will be potential biomarkers, and it is expected that there will be standardised guidelines for their application.

Clinical relevance of cleaved RAGE plasma levels as a biomarker of disease severity and functional outcome in aneurysmal subarachnoid hemorrhage

BACKGROUND

Cleaved receptor for advanced glycation end-products (cRAGE) has been introduced as a new inflammatory marker. We clarified the associations between cRAGE levels, disease severity and functional outcome in aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

In this prospective, observational study, plasma levels of total soluble RAGE (sRAGE) and endogenous secretory RAGE (esRAGE) were quantified in 108 aSAH patients and 108 controls. The level of cRAGE was calculated by subtracting the level of esRAGE from that of sRAGE. World Federation of Neurological Surgeons (WFNS) score, modified Fisher score, and Hunt Hess (HH) score were recorded to assess aSAH severity. Relationship between plasma cRAGE levels and 6-month poor outcome (Glasgow Outcome Scale score of 1-3) was assess using multivariate analysis.

RESULTS

Plasma cRAGE levels were significantly higher in patients than in controls. Its levels were significantly correlated with WNFS score, modified Fisher score and HH score of patients. Plasma cRAGE emerged as an independent predictor for 6-month poor outcome. Area under receiver operating characteristic curve (AUC) of this biomarker was similar to those of WNFS score, modified Fisher score and HH score. Moreover, it significantly improved AUCs of WNFS score, modified Fisher score and HH score.

CONCLUSIONS

Plasma cRAGE levels are highly associated with the severity and poor prognosis in aSAH.

Role of Damage Associated Molecular Pattern Molecules (DAMPs) in Aneurysmal Subarachnoid Hemorrhage (aSAH)

Aneurysmal subarachnoid hemorrhage (aSAH) represents only a small portion of all strokes, but accounts for almost half of the deaths caused by stroke worldwide. Neurosurgical clipping and endovascular coiling can successfully obliterate the bleeding aneurysms, but ensuing complications such as cerebral vasospasm, acute and chronic hydrocephalus, seizures, cortical spreading depression, delayed ischemic neurological deficits, and delayed cerebral ischemia lead to poor clinical outcomes. The mechanisms leading to these complications are complex and poorly understood. Early brain injury resulting from transient global ischemia can release molecules that may be critical to initiate and sustain inflammatory response. Hence, the events during early brain injury can influence the occurrence of delayed brain injury. Since the damage associated molecular pattern molecules (DAMPs) might be the initiators of inflammation in the pathophysiology of aSAH, so the aim of this review is to highlight their role in the context of aSAH from diagnostic, prognostic, therapeutic, and drug therapy monitoring perspectives. DAMPs represent a diverse and a heterogenous group of molecules derived from different compartments of cells upon injury. Here, we have reviewed the most important DAMPs molecules including high mobility group box-1 (HMGB1), S100B, hemoglobin and its derivatives, extracellular matrix components, IL-1α, IL-33, and mitochondrial DNA in the context of aSAH and their role in post-aSAH complications and clinical outcome after aSAH.

Danger signals in trauma

This review summarizes a short list of currently discussed trauma-induced danger-associated molecular patterns (DAMP). Due to the bivalent character and often pleiotropic effects of a DAMP, it is difficult to describe its "friend or foe" role in post-traumatic inflammation and regeneration, both systemically as well locally in tissues. DAMP can be used as biomarkers to indicate or monitor disease or injury severity, but also may serve as clinically applicable parameters for better indication and timing of surgery. Due to the inflammatory processes at the local tissue level or the systemic level, the precise role of DAMP is not always clear to define. While in vitro and experimental studies allow for the detection of these biomarkers at the different levels of an organism-cellular, tissue, circulation-this is not always easily transferable to the human setting. Increased knowledge exploring the dual role of DAMP after trauma, and concentrating on their nuclear functions, transcriptional targets, release mechanisms, cellular sources, multiple functions, their interactions and potential therapeutic targeting is warranted.

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.

Clinical significance of changes in IL-6, CRP and S100in serum and NO in cerebrospinal fluid insubarachnoid hemorrhage and prognosis

Clinical significance of changes in interleukin-6 (IL-6), C-reactive protein (CRP) and S100 in serum and NO was investigated in cerebrospinal fluid (CSF) in subarachnoid hemorrhage (SAH) and its prognosis. A total of 43 SAH patients and 23 healthy subjects were selected and divided into cerebral vasospasm (CVS) group and non-CVS group, and favorable prognosis group and unfavorable prognosis group according to Hunt-Hess grade. The levels of IL-6, CRP, S100 and NO in CSF were detected, respectively, followed by statistical analysis of correlation. The higher the Hunt grade was, the higher the factor expression was; the expression levels of IL-6, CRP, S100 and NO in CSF were gradually increased in CVS group and unfavorable prognosis group, and the differences were significant compared with those in the control group. There was a positive correlation between the expression levels of each of the two factors among IL-6, CRP, S100 and NO in CSF, and the differences were statistically significant (P<0.05). The expression levels of IL-6, CRP, S100 and NO in CSF in SAH patients are significantly increased, showing positive correlations and participating in the occurrence and development of SAH, which provide new directions for the early clinical diagnosis of SAH.

S100B, NSE and MMP-9 fail to predict neurologic outcome while elevated S100B associates with milder initial clinical presentation after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Despite advances in the treatment of aneurysmal subarachnoid hemorrhage (aSAH) one-year mortality remains approximately 50%. Making an accurate prognosis at the early phase of the disease is notoriously difficult. A clinically reliable biomarker that could be used for better prediction of prognosis and/or as a surrogate for developing complications after aSAH is still lacking. In this study, we evaluated the prognostic values of three promising biomarkers, i.e. S100B, NSE, and MMP-9 in aSAH.

METHODS

In this prospective population-based study, S100B, NSE, and MMP-9 levels were measured in 47 aSAH patients for up to five days. Blood samples were taken at 0, 12 and 24 h after the admission to the intensive care unit (ICU) and daily after that until the patient was transferred from the ICU. The patients' neurological outcome was evaluated with the modified Rankin Scale (mRS) at six months after aSAH.

RESULTS

Biomarker-levels measured during the first 24 h were not associated with neurological outcome. S100B levels during the first 24 h were elevated in patients with a non-severe initial clinical presentation. Otherwise, there was no association between selected clinical variables and the early biomarker levels. In 22 patients, whose ICU follow-up lasted for up to five days, the total release of biomarkers was not associated with the neurological outcome.

CONCLUSIONS

None of the measured biomarkers were associated with the neurological outcome evaluated at six months after aSAH. Elevated levels of S100B in patients with non-severe initial presentation suggest an adaptive role of this biomarker in aSAH. Based on our findings it is not advisable to use these biomarkers to guide clinical decision-making in patients with aSAH.

Determining the Value of Cerebrospinal Fluid Lactate Dehydrogenase Level in Differentiating Subarachnoid Hemorrhage From Traumatic Lumbar Puncture

Context

Lumbar puncture (LP) is still an important modality in the diagnosis of subarachnoid hemorrhage (SAH). Rapid and correct fluid analysis can provide patients with a better prognosis by appropriate intervention.

Objective

To determine the value of cerebrospinal fluid lactate dehydrogenase level in differentiation between SAH and traumatic LP.

Design

This was a cross-sectional observational study. Patients with a diagnostic suspicion of SAH who were admitted to the emergency department were enrolled in our study based on the inclusion criteria. All patients underwent head computed tomography scan without contrast. Patients with SAH confirmed on computed tomography scan and those who needed surgical intervention underwent LP by the neurosurgical service in the operation room (group 1). Other patients who fulfilled the inclusion criteria but had a traumatic LP in the emergency setting were also enrolled in our study (group 2). The fluid samples of all LPs were sent to the laboratory to be analyzed. Finally, we compared the results of the 2 groups with each other.

Results

Fifty-two patients were enrolled in our study, 26 patients (50%) from each group. The cerebrospinal fluid lactate dehydrogenase level was significantly higher in group 1 than it was in group 2 (P &lt; .001), and based on receiver operating characteristic curve analysis, the significant level of cerebrospinal fluid lactate dehydrogenase to differentiate SAH from traumatic LP was estimated to be 185. The red blood cell and white blood cell counts were significantly higher in group 1 than they were in group 2 (P &lt; .001).

Conclusions

Cerebrospinal fluid lactate dehydrogenase can effectively differentiate SAH from traumatic tap in LP samples.

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

PURPOSE

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

METHODS

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

PRINCIPAL RESULTS

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

MAJOR CONCLUSIONS

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

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.

Comparison of plasma copeptin and multiple biomarkers for assessing prognosis of patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Increased plasma copeptin concentrations are related to poor prognosis after aneurysmal subarachnoid hemorrhage (aSAH). The aim of this study was to assess prognostic significance of plasma copeptin detection compared with glial fibrillary astrocyte protein, myelin basic protein, S100B, phosphorylated axonal neurofilament subunit H, neuron-specific enolase, tau and ubiquitin carboxyl-terminal hydrolase L1 in aSAH.

METHODS

We detected plasma concentrations of the aforementioned biomarkers in 105 healthy controls using ELISA. Their predictive ability for symptomatic cerebral vasospasm and 6-month poor outcome (Glasgow Outcome Scale score of 1-3) were compared.

RESULTS

Plasma concentrations of the preceding biomarkers were highly correlated with World Federation of Neurological Surgeons subarachnoid hemorrhage scale (WFNS) scores as well as were significantly higher in patients with symptomatic cerebral vasospasm than in those without symptomatic cerebral vasospasm and in patients with poor outcome than in those with good outcome. In terms of area under receiver operating characteristic curve, their predictive value for symptomatic cerebral vasospasm and 6-month poor outcome was in the range of WFNS scores. Plasma copeptin concentration, but not plasma concentrations of other biomarkers, statistically significantly improved the predictive performance of WFNS scores.

CONCLUSIONS

Copeptin in plasma might have the potential to be a useful prognostic biomarker for aSAH.

The Effect of Mechanical Ventilation on TASK-1 Expression in the Brain in a Rat Model

Background and Objective

TWIK-related acid-sensitive potassium channel 1 (TASK-1) is closely related to respiratory central control and neuronal injury. We investigated the effect of MV on TASK-1's functions and explored the mechanism using a rat model.

Methods

Male Sprague-Dawley rats were randomized to three groups: (1) high tidal volume (HVt): MV for four hours with Vt at 10 mL/kg; (2) low Vt (LVt): MV for four hours with Vt at 5 mL/kg; (3) basal (BAS): anesthetized and unventilated animals. We measured lung histology and plasma and brain levels of proteins (IL-6, TNF-α, and S-100B) and determined TASK-1 levels in rat brainstems as a marker of respiratory centre activity.

Results

The LISs (lung injury scores) were significantly higher in the HVt group. Brain inflammatory cytokines levels were different to those in serum. TASK-1 levels were significantly lower in the MV groups (P = 0.002) and the HVt group tended to have a lower level of TASK-1 than the LVt group.

Conclusion

MV causes not only lung injury, but also brain injury. MV affects the regulation of the respiratory centre, perhaps causing damage to it. Inflammation is probably not the main mechanism of ventilator-related brain injury.

Evaluation of dietary and lifestyle changes as modifiers of S100β levels in Alzheimer's disease

There is a significant body of research undertaken in order to elucidate the mechanisms underlying the pathology of Alzheimer's disease (AD), as well as to discover early detection biomarkers and potential therapeutic strategies. One such proposed biomarker is the calcium binding protein S100β, which, depending on its local concentration, is known to exhibit both neurotrophic and neuroinflammatory properties in the central nervous system. At present, relatively little is known regarding the effect of chronic S100β disruption in AD. Dietary intake has been identified as a modifiable risk factor for AD. Preliminary in vitro and animal studies have demonstrated an association between S100β expression and dietary intake which links to AD pathophysiology. This review describes the association of S100β to fatty acids, ketone bodies, insulin, and botanicals as well as the potential impact of physical activity as a lifestyle factor. We also discuss the prospective implications of these findings, including support of the use of a Mediterranean dietary pattern and/or the ketogenic diet as an approach to modify AD risk.

Serial Sampling of Serum Protein Biomarkers for Monitoring Human Traumatic Brain Injury Dynamics: A Systematic Review

BACKGROUND

The proteins S100B, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and neurofilament light (NF-L) have been serially sampled in serum of patients suffering from traumatic brain injury (TBI) in order to assess injury severity and tissue fate. We review the current literature of serum level dynamics of these proteins following TBI and used the term "effective half-life" (t1/2) in order to describe the "fall" rate in serum.

MATERIALS AND METHODS

Through searches on EMBASE, Medline, and Scopus, we looked for articles where these proteins had been serially sampled in serum in human TBI. We excluded animal studies, studies with only one presented sample and studies without neuroradiological examinations.

RESULTS

Following screening (10,389 papers), n = 122 papers were included. The proteins S100B (n = 66) and NSE (n = 27) were the two most frequent biomarkers that were serially sampled. For S100B in severe TBI, a majority of studies indicate a t1/2 of about 24 h, even if very early sampling in these patients reveals rapid decreases (1-2 h) though possibly of non-cerebral origin. In contrast, the t1/2 for NSE is comparably longer, ranging from 48 to 72 h in severe TBI cases. The protein GFAP (n = 18) appears to have t1/2 of about 24-48 h in severe TBI. The protein UCH-L1 (n = 9) presents a t1/2 around 7 h in mild TBI and about 10 h in severe. Frequent sampling of these proteins revealed different trajectories with persisting high serum levels, or secondary peaks, in patients with unfavorable outcome or in patients developing secondary detrimental events. Finally, NF-L (n = 2) only increased in the few studies available, suggesting a serum availability of >10 days. To date, automated assays are available for S100B and NSE making them faster and more practical to use.

CONCLUSION

Serial sampling of brain-specific proteins in serum reveals different temporal trajectories that should be acknowledged. Proteins with shorter serum availability, like S100B, may be superior to proteins such as NF-L in detection of secondary harmful events when monitoring patients with TBI.

Heparin and Heparin-Derivatives in Post-Subarachnoid Hemorrhage Brain Injury: A Multimodal Therapy for a Multimodal Disease

Pharmacologic efforts to improve outcomes following aneurysmal subarachnoid hemorrhage (aSAH) remain disappointing, likely owing to the complex nature of post-hemorrhage brain injury. Previous work suggests that heparin, due to the multimodal nature of its actions, reduces the incidence of clinical vasospasm and delayed cerebral ischemia that accompany the disease. This narrative review examines how heparin may mitigate the non-vasospastic pathological aspects of aSAH, particularly those related to neuroinflammation. Following a brief review of early brain injury in aSAH and heparin’s general pharmacology, we discuss potential mechanistic roles of heparin therapy in treating post-aSAH inflammatory injury. These roles include reducing ischemia-reperfusion injury, preventing leukocyte extravasation, modulating phagocyte activation, countering oxidative stress, and correcting blood-brain barrier dysfunction. Following a discussion of evidence to support these mechanistic roles, we provide a brief discussion of potential complications of heparin usage in aSAH. Our review suggests that heparin’s use in aSAH is not only safe, but effectively addresses a number of pathologies initiated by aSAH.

Brain Monitoring in Critically Neurologically Impaired Patients

Assessment of neurologic injury and the evolution of severe neurologic injury is limited in comatose or critically ill patients that lack a reliable neurologic examination. For common yet severe pathologies such as the comatose state after cardiac arrest, aneurysmal subarachnoid hemorrhage (aSAH), and severe traumatic brain injury (TBI), critical medical decisions are made on the basis of the neurologic injury. Decisions regarding active intensive care management, need for neurosurgical intervention, and withdrawal of care, depend on a reliable, high-quality assessment of the true state of neurologic injury, and have traditionally relied on limited assessments such as intracranial pressure monitoring and electroencephalogram. However, even within TBI there exists a spectrum of disease that is likely not captured by such limited monitoring and thus a more directed effort towards obtaining a more robust biophysical signature of the individual patient must be undertaken. In this review, multimodal monitoring including the most promising serum markers of neuronal injury, cerebral microdialysis, brain tissue oxygenation, and pressure reactivity index to access brain microenvironment will be discussed with their utility among specific pathologies that may help determine a more complete picture of the neurologic injury state for active intensive care management and long-term outcomes. Goal-directed therapy guided by a multi-modality approach appears to be superior to standard intracranial pressure (ICP) guided therapy and should be explored further across multiple pathologies. Future directions including the application of optogenetics to evaluate brain injury and recovery and even as an adjunct monitoring modality will also be discussed.

Fluid Biomarkers of Traumatic Brain Injury and Intended Context of Use

Traumatic brain injury (TBI) is one of the leading causes of death and disability around the world. The lack of validated biomarkers for TBI is a major impediment to developing effective therapies and improving clinical practice, as well as stimulating much work in this area. In this review, we focus on different settings of TBI management where blood or cerebrospinal fluid (CSF) biomarkers could be utilized for predicting clinically-relevant consequences and guiding management decisions. Requirements that the biomarker must fulfill differ based on the intended context of use (CoU). Specifically, we focus on fluid biomarkers in order to: (1) identify patients who may require acute neuroimaging (cranial computerized tomography (CT) or magnetic resonance imaging (MRI); (2) select patients at risk for secondary brain injury processes; (3) aid in counseling patients about their symptoms at discharge; (4) identify patients at risk for developing postconcussive syndrome (PCS), posttraumatic epilepsy (PTE) or chronic traumatic encephalopathy (CTE); (5) predict outcomes with respect to poor or good recovery; (6) inform counseling as to return to work (RTW) or to play. Despite significant advances already made from biomarker-based studies of TBI, there is an immediate need for further large-scale studies focused on identifying and innovating sensitive and reliable TBI biomarkers. These studies should be designed with the intended CoU in mind.