Serum S-100B protein in severe head injury

Admission S100B fails as neuro-marker but is a good predictor for intrahospital mortality in major trauma patients

BACKGROUND

S100 B is an extensively studied neuro-trauma marker, but its specificity and subsequently interpretation in major trauma patients might be limited, since extracerebral injuries are known to increase serum levels. Thus, we evaluated the potential role of S100B in the assessment of severe traumatic brain injury (TBI) in multiple injured patients upon emergency room (ER) admission and the first days of intensive care unit (ICU) stay.

METHODS

Retrospective study employing trauma registry data derived from a level 1 trauma center. Four cohorts of patients were grouped: isolated TBI (iTBI), polytrauma patients with TBI (PT + TBI), polytrauma patients without TBI (PT-TBI) and patients without polytrauma or TBI (control). S100B-serum levels were assessed immediately after admission in the emergency room and during the subsequent ICU stay. Values were correlated with injury severity score (ISS), Glasgow Coma Score (GCS) and in-hospital mortality.

RESULTS

780 predominantly male patients (76 %) with a median age of 48 (30-63) and a median ISS of 24 (17-30) were enrolled in the study. Admission S100B correlated with ISS and TBI severity defined by the GCS (both p < 0.0001) but not with head abbreviated injury score (AIS) (p = 0.38). Compared with survivors, non-survivors had significantly higher median S100B levels in the ER (6.14 μg/L vs. 2.06 μg/L; p < 0.0001) and at ICU-day 1 (0.69 μg/L vs. 0.17 μg/L; p < 0.0001). S100B in the ER predicted mortality with an area under curve (AUC) of 0.77 (95 % CI 0,70-0,83, p < 0.0001), vs. 0.86 at ICU-day 1 (95 % CI 0,80-0,91, p < 0.0001).

CONCLUSION

In conclusion, S100B is a valid biomarker for prediction of mortality in major trauma patients with a higher accuracy when assessed at the first day of ICU stay vs. immediately after ER admission. Since S100B did not correlate with pathologic TBI findings in multiple injured patients, it failed as predictive neuro-marker because extracerebral injuries demonstrated a higher influence on admission levels than neurotrauma. Although S100B levels are indicative for injury severity they should be interpreted with caution in polytrauma patients.

Post-mortem detection of neuronal and astroglial biochemical markers in serum and urine for diagnostics of traumatic brain injury

Currently available epidemiological data shows that traumatic brain injury (TBI) represents one of the leading causes of death that is associated with medico-legal practice, including forensic autopsy, criminological investigation, and neuropathological examination. Attention focused on TBI research is needed to advance its diagnostics in ante- and post-mortem cases with regard to identification and validation of novel biomarkers. Recently, several markers of neuronal, astroglial, and axonal injury have been explored in various biofluids to assess the clinical origin, progression, severity, and prognosis of TBI. Despite clinical usefulness, understanding their diagnostic accuracy could also potentially help translate them either into forensic or medico-legal practice, or both. The aim of this study was to evaluate post-mortem pro-BDNF, NSE, UCHL1, GFAP, S100B, SPTAN1, NFL, MAPT, and MBP levels in serum and urine in TBI cases. The study was performed using cases (n = 40) of fatal head injury and control cases (n = 20) of sudden death. Serum and urine were collected within ∼ 24 h after death and compared using ELISA test. In our study, we observed the elevated concentration levels of GFAP and MAPT in both serum and urine, elevated concentration levels of S100B and SPTAN1 in serum, and decreased concentration levels of pro-BDNF in serum compared to the control group. The obtained results anticipate the possible implementation of performed assays as an interesting tool for forensic and medico-legal investigations regarding TBI diagnosis where the head injury was not supposed to be the direct cause of death.

The immune suppressive properties of damage associated molecular patterns in the setting of sterile traumatic injury

Associated with the development of hospital-acquired infections, major traumatic injury results in an immediate and persistent state of systemic immunosuppression, yet the underlying mechanisms are poorly understood. Detected in the circulation in the minutes, days and weeks following injury, damage associated molecular patterns (DAMPs) are a heterogeneous collection of proteins, lipids and DNA renowned for initiating the systemic inflammatory response syndrome. Suggesting additional immunomodulatory roles in the post-trauma immune response, data are emerging implicating DAMPs as potential mediators of post-trauma immune suppression. Discussing the results of in vitro, in vivo and ex vivo studies, the purpose of this review is to summarise the emerging immune tolerising properties of cytosolic, nuclear and mitochondrial-derived DAMPs. Direct inhibition of neutrophil antimicrobial activities, the induction of endotoxin tolerance in monocytes and macrophages, and the recruitment, activation and expansion of myeloid derived suppressor cells and regulatory T cells are examples of some of the immune suppressive properties assigned to DAMPs so far. Crucially, with studies identifying the molecular mechanisms by which DAMPs promote immune suppression, therapeutic strategies that prevent and/or reverse DAMP-induced immunosuppression have been proposed. Approaches currently under consideration include the use of synthetic polymers, or the delivery of plasma proteins, to scavenge circulating DAMPs, or to treat critically-injured patients with antagonists of DAMP receptors. However, as DAMPs share signalling pathways with pathogen associated molecular patterns, and pro-inflammatory responses are essential for tissue regeneration, these approaches need to be carefully considered in order to ensure that modulating DAMP levels and/or their interaction with immune cells does not negatively impact upon anti-microbial defence and the physiological responses of tissue repair and wound healing.

Association of Brain Injury Biomarkers and Circulatory Shock Following Moderate-Severe Traumatic Brain Injury: A TRACK-TBI Study

INTRODUCTION

Early circulatory shock following traumatic brain injury (TBI) is a multifactorial process; however, the impact of brain injury biomarkers on the risk of shock has not been evaluated. We examined the association between neuronal injury biomarker levels and the development of circulatory shock following moderate-severe TBI.

METHODS

In this retrospective cohort study, we examined adults with moderate-severe TBI (Glasgow Coma Scale score <13) enrolled in the TRACK-TBI study, an 18-center prospective TBI cohort study. The exposures were day-1 levels of neuronal injury biomarkers (glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1 [UCH-L1], S100 calcium-binding protein B [S100B], neuron-specific enolase), and of an inflammatory biomarker (high-sensitivity C-reactive protein). The primary outcome was the development of circulatory shock, defined as cardiovascular Sequential Organ Failure Assessment Score ≥2 within 72 hours of admission. Association between day-1 biomarker levels and the development of circulatory shock was assessed with regression analysis.

RESULTS

The study included 392 subjects, with a mean age of 40 years; 314 (80%) were male and 165 (42%) developed circulatory shock. Median (interquartile range) day-1 levels of UCH-L1 (994.8 [518.7 to 1988.2] pg/mL vs. 548.1 [280.2 to 1151.9] pg/mL; P <0.0001) and S100B (0.47 μg/mL [0.25 to 0.88] vs. 0.27 [0.16 to 0.46] μg/mL; P <0.0001) were elevated in those who developed early circulatory shock compared with those who did not. In multivariable regression, there were associations between levels of both UCH-L1 (odds ratio, 1.63 [95% confidence interval, 1.25-2.12]; P <0.0005) and S100B (odds ratio, 1.73 [95% confidence interval 1.27-2.36]; P <0.0005) with the development of circulatory shock.

CONCLUSION

Neuronal injury biomarkers may provide the improved mechanistic understanding and possibly early identification of patients at risk for early circulatory shock following moderate-severe TBI.

Salivary S100 calcium-binding protein beta (S100B) and neurofilament light (NfL) after acute exposure to repeated head impacts in collegiate water polo players

Blood-based biomarkers of brain injury may be useful for monitoring brain health in athletes at risk for concussions. Two putative biomarkers of sport-related concussion, neurofilament light (NfL), an axonal structural protein, and S100 calcium-binding protein beta (S100B), an astrocyte-derived protein, were measured in saliva, a biofluid which can be sampled in an athletic setting without the risks and burdens associated with blood sampled by venipuncture. Samples were collected from men’s and women’s collegiate water polo players (n = 65) before and after a competitive tournament. Head impacts were measured using sensors previously evaluated for use in water polo, and video recordings were independently reviewed for the purpose of validating impacts recorded by the sensors. Athletes sustained a total of 107 head impacts, all of which were asymptomatic (i.e., no athlete was diagnosed with a concussion or more serious). Post-tournament salivary NfL was directly associated with head impact frequency (RR = 1.151, p = 0.025) and cumulative head impact magnitude (RR = 1.008, p = 0.014), while controlling for baseline salivary NfL. Change in S100B was not associated with head impact exposure (RR < 1.001, p > 0.483). These patterns suggest that repeated head impacts may cause axonal injury, even in asymptomatic athletes.

Interferon-β Activity Is Affected by S100B Protein

Interferon-β (IFN-β) is a pleiotropic cytokine secreted in response to various pathological conditions and is clinically used for therapy of multiple sclerosis. Its application for treatment of cancer, infections and pulmonary diseases is limited by incomplete understanding of regulatory mechanisms of its functioning. Recently, we reported that IFN-β activity is affected by interactions with S100A1, S100A4, S100A6, and S100P proteins, which are members of the S100 protein family of multifunctional Ca²⁺-binding proteins possessing cytokine-like activities (Int J Mol Sci. 2020;21(24):9473). Here we show that IFN-β interacts with one more representative of the S100 protein family, the S100B protein, involved in numerous oncological and neurological diseases. The use of chemical crosslinking, intrinsic fluorescence, and surface plasmon resonance spectroscopy revealed IFN-β binding to Ca²⁺-loaded dimeric and monomeric forms of the S100B protein. Calcium depletion blocks the S100B–IFN-β interaction. S100B monomerization increases its affinity to IFN-β by 2.7 orders of magnitude (equilibrium dissociation constant of the complex reaches 47 pM). Crystal violet assay demonstrated that combined application of IFN-β and S100B (5–25 nM) eliminates their inhibitory effects on MCF-7 cell viability. Bioinformatics analysis showed that the direct modulation of IFN-β activity by the S100B protein described here could be relevant to progression of multiple oncological and neurological diseases.

Specific cytokines of interleukin-6 family interact with S100 proteins

Cytokines of interleukin-6 (IL-6) family are important signaling proteins involved in various physiological and pathological processes. Earlier, we described interactions between IL-11 and S100P/B proteins from the family of S100 proteins engaged in the pathogenesis of numerous diseases. We probed here interactions between seven IL-6 family cytokines (IL-6, IL-11, OSM, LIF, CNTF, CT-1, and CLCF1) and fourteen S100 proteins (S100A1/A4/A6/A7/A8/A9/A10/A11/A12/A13/A14/A15/B/P). Surface plasmon resonance spectroscopy revealed formation of calcium-dependent complexes between IL-11, OSM, CNTF, CT-1, and CLCF1 and distinct subsets of S100A1/A6/B/P proteins with equilibrium dissociation constants of 19 nM - 12 µM. The existence of a network of interactions between Ca²⁺-loaded S100 proteins and IL-6 family cytokines suggest regulation of these cytokines by the extracellular forms of S100 proteins.

Diffuse Axonal Injury: Clinical Prognostic Factors, Molecular Experimental Models and the Impact of the Trauma Related Oxidative Stress. An Extensive Review Concerning Milestones and Advances

Traumatic brain injury (TBI) is a condition burdened by an extremely high rate of morbidity and mortality and can result in an overall disability rate as high as 50% in affected individuals. Therefore, the importance of identifying clinical prognostic factors for diffuse axonal injury (DAI) in (TBI) is commonly recognized as critical. The aim of the present review paper is to evaluate the most recent contributions from the relevant literature in order to understand how each single prognostic factor determinates the severity of the clinical syndrome associated with DAI. The main clinical factors with an important impact on prognosis in case of DAI are glycemia, early GCS, the peripheral oxygen saturation, blood pressure, and time to recover consciousness. In addition, the severity of the lesion, classified on the ground of the cerebral anatomical structures involved after the trauma, has a strong correlation with survival after DAI. In conclusion, modern findings concerning the role of reactive oxygen species (ROS) and oxidative stress in DAI suggest that biomarkers such as GFAP, pNF-H, NF-L, microtubule associated protein tau, Aβ42, S-100β, NSE, AQP4, Drp-1, and NCX represent a possible critical target for future pharmaceutical treatments to prevent the damages caused by DAI.

Immunohistochemistry in postmortem diagnosis of acute cerebral hypoxia and ischemia: A systematic review

BACKGROUND

: Discovery of evidence of acute brain ischemia or hypoxia and its differentiation from agonal hypoxia represents a task of interest but extremely difficult in forensic neuropathology. Generally, more than 50% of forensic autopsies indicate evidence of brain induced functional arrest of the organ system, which can be the result of a hypoxic/ischemic brain event. Even if the brain is the target organ of hypoxic/ischemic damage, at present, there are no specific neuropathological (macroscopic and histological) findings of hypoxic damage (such as in drowning, hanging, intoxication with carbon monoxide) or acute ischemia. In fact, the first histological signs appear after at least 4 to 6 hours. Numerous authors have pointed out how an immunohistochemical analysis could help diagnose acute cerebral hypoxia/ischemia.Data sources: This review was based on articles published in PubMed and Scopus databases in the past 25 years, with the following keywords "immunohistochemical markers," "acute cerebral ischemia," "ischemic or hypoxic brain damage," and "acute cerebral hypoxia".

OBJECTIVES

: Original articles and reviews on this topic were selected. The purpose of this review is to analyze and summarize the markers studied so far and to consider the limits of immunohistochemistry that exist to date in this specific field of forensic pathology.

RESULTS

: We identified 13 markers that had been examined (in previous studies) for this purpose. In our opinion, it is difficult to identify reliable and confirmed biomarkers from multiple studies in order to support a postmortem diagnosis of acute cerebral hypoxia/ischemia. Microtubule-associated protein 2 (MAP2) is the most researched marker in the literature and the results obtained have proven to be quite useful.

CONCLUSION

Immunohistochemistry has provided interesting and promising results, but further studies are needed in order to confirm and apply them in standard forensic practice.

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.

Serum Concentrations of Neuron-Specific Enolase in Dogs Following Traumatic Brain Injury

The ability to make an accurate prognosis, which is a prerequisite for treatment decisions, is very limited in dogs with traumatic brain injury (TBI). To determine whether serum concentrations of neuron-specific enolase (NSE) have prognostic value in dogs following TBI, we conducted a prospective, observational, controlled clinical study in an intensive care unit of a university teaching hospital. The study population comprised 24 dogs admitted to the hospital within 72 h of a known event of TBI between January 2010 and January 2015, as well as 25 control healthy shelter dogs admitted for elective neutering. Seventeen injured dogs (70%) survived to discharge, four were euthanized and three died within 48 h. Serum samples were obtained from all dogs (in injured dogs, within 72 h of TBI) and NSE concentrations were measured using enzyme-linked immonosorbent assay. Associations between NSE levels and outcome, Modified Glasgow Coma Scale, time to sampling, age or haemolysis scale were determined. Mean serum NSE concentrations were decreased in dogs with TBI compared with healthy controls (19.4 ± 4.14 ng/ml vs. 24.9 ± 4.6 ng/ml, P <0.001). No association was found between serum NSE concentrations and either survival or severity of neurological impairment. A negative correlation was found between serum NSE concentrations and time from trauma to blood collection (r = -0.50, P = 0.022). These results indicate that serum NSE concentration in dogs following TBI is not an effective marker for severity or outcome. Further studies are warranted to standardize serum NSE measurements in dogs and to determine the peak and half-life levels of this potential biomarker.

Investigating the Levels of Brain-Specific Proteins in Hydrocephalus Patients

BACKGROUND

Hydrocephalus, a common brain disorder in children, can cause permanent brain damage. A timely diagnosis of this disorder is crucial.

OBJECTIVE

The aim of this study was to evaluate the levels of S-100, CK-18, and NSE brainspecific proteins in patients with hydrocephalus. We examined the levels of these proteins in the blood samples of hydrocephalic patients.

METHODS

The study was conducted on the hydrocephalus (n = 31) patients and a healthy control group (n = 30). A Receiver Operating Characteristic (ROC) curve was used to assess the validity of the NSE, CK-18, and S100B to differentiate between the hydrocephalus and the control groups. The suitability of the data to the normal distribution was tested with the Shapiro Wilk test, and the Student t-test was used to compare the characteristics of the normal distribution in two independent groups. The individuals in the hydrocephalus and control groups had similar values in terms of age, height, and weight.

RESULTS

It was observed that NSE, CK-18, and S100B mean values of the individuals in the hydrocephalus group were significantly higher than NSE, CK-18, and S100B mean values of the control group.

CONCLUSION

Experiments have shown that the levels of these proteins increase significantly in hydrocephalus patients compared to the healthy group. These three parameters can be considered as important markers in the diagnosis of hydrocephalus.

Biomarkers Facilitate the Assessment of Prognosis in Critically Ill Patients with Primary Brain Injury: A Cohort Study

Primary injuries to the brain are common causes of hospitalization of patients in intensive care units (ICU). The Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system is widely used for prognostication among critically ill subjects. Biomarkers help to monitor the severity of neurological status. This study aimed to identify the best biomarker, along with APACHE II score, in mortality prediction among patients admitted to the ICU with the primary brain injury. This cohort study covered 58 patients. APACHE II scores were assessed 24 h post ICU admission. The concentrations of six biomarkers were determined, including the C-reactive protein (CRP), the S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), neutrophil gelatinase-associated lipocalin (NGAL), matrix metalloproteinase 9 (MMP-9), and tissue inhibitor of metalloproteinase 1 (TIMP-1), using commercially available ELISA kits. The biomarkers were specifically chosen for this study due to their established connection to the pathophysiology of brain injury. In-hospital mortality was the outcome. Median APACHE II was 18 (IQR 13–22). Mortality reached 40%. Median concentrations of the CRP, NGAL, S100B, and NSE were significantly higher in deceased patients. S100B (AUC = 0.854), NGAL (AUC = 0.833), NSE (AUC = 0.777), and APACHE II (AUC = 0.766) were the best independent predictors of mortality. Combination of APACHE II with S100B, NSE, NGAL, and CRP increased the diagnostic accuracy of mortality prediction. MMP and TIMP-1 were impractical in prognostication, even after adjustment for APACHE II score. S100B protein and NSE seem to be the best predictors of compromised outcome among critically ill patients with primary brain injuries and should be assessed along with the APACHE II calculation after ICU admission.

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.

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.

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.

Trauma-Induced Damage-Associated Molecular Patterns-Mediated Remote Organ Injury and Immunosuppression in the Acutely Ill Patient

Trauma is one of the leading causes of death and disability in the world. Multiple trauma or isolated traumatic brain injury are both indicative of human tissue damage. In the early phase after trauma, damage-associated molecular patterns (DAMPs) are released and give rise to sterile systemic inflammatory response syndrome (SIRS) and organ failure. Later, protracted inflammation following sepsis will favor hospital-acquired infection and will worsen patient’s outcome through immunosuppression. Throughout medical care or surgical procedures, severe trauma patients will be subjected to endogenous or exogenous DAMPs. In this review, we summarize the current knowledge regarding DAMP-mediated SIRS or immunosuppression and the clinical consequences in terms of organ failure and infections.

Serum levels of S100B from jugular bulb as a biomarker of poor prognosis in patients with severe acute brain injury

AIMS/BACKGROUND

To evaluate the correlation between protein S100B concentrations measured in the jugular bulb as well as at peripheral level and the prognostic usefulness of this marker.

METHODS

A prospective study of all patients admitted to the intensive care unit with acute brain damage was carried out. Peripheral and jugular bulb blood samples were collected upon admission and every 24h for three days. The endpoints were brain death diagnosis and the Glasgow Outcome Scale score after 6months.

RESULTS

A total of 83 patients were included. Jugular protein S100B levels were greater than systemic levels upon admission and also after 24 and 72h (mean difference>0). Jugular protein S100B levels showed acceptable precision in predicting brain death both upon admission [AUC 0.67 (95% CI 0.53-0.80)] and after 48h [AUC 0.73 (95% CI 0.57-0.89)]. Similar results were obtained regarding the capacity of jugular protein S100B levels upon admission to predict an unfavourable outcome (AUC 0.69 (95% CI 0.56-0.79)). The gradient upon admission (jugular-peripheral levels) showed its capacity to predict the development of brain death [AUC 0.74 (95% CI 0.62-0.86)] and together with the Glasgow Coma Scale constituted the independent factors associated with the development of brain death.

CONCLUSION

Regional protein S100B determinations are higher than systemic determinations, thus confirming the cerebral origin of protein S100B. The transcranial protein S100B gradient is correlated to the development of brain death.

Biomarkers in traumatic brain injury (TBI): a review

Biomarkers can be broadly defined as qualitative or quantitative measurements that convey information on the physiopathological state of a subject at a certain time point or disease state. Biomarkers can indicate health, pathology, or response to treatment, including unwanted side effects. When used as outcomes in clinical trials, biomarkers act as surrogates or substitutes for clinically meaningful endpoints. Biomarkers of disease can be diagnostic (the identification of the nature and cause of a condition) or prognostic (predicting the likelihood of a person's survival or outcome of a disease). In addition, genetic biomarkers can be used to quantify the risk of developing a certain disease. In the specific case of traumatic brain injury, surrogate blood biomarkers of imaging can improve the standard of care and reduce the costs of diagnosis. In addition, a prognostic role for biomarkers has been suggested in the case of post-traumatic epilepsy. Given the extensive literature on clinical biomarkers, we will focus herein on biomarkers which are present in peripheral body fluids such as saliva and blood. In particular, blood biomarkers, such as glial fibrillary acidic protein and salivary/blood S100B, will be discussed together with the use of nucleic acids (eg, DNA) collected from peripheral cells.

Diffuse Axonal Injury and Oxidative Stress: A Comprehensive Review

Traumatic brain injury (TBI) is one of the world’s leading causes of morbidity and mortality among young individuals. TBI applies powerful rotational and translational forces to the brain parenchyma, which results in a traumatic diffuse axonal injury (DAI) responsible for brain swelling and neuronal death. Following TBI, axonal degeneration has been identified as a progressive process that starts with disrupted axonal transport causing axonal swelling, followed by secondary axonal disconnection and Wallerian degeneration. These modifications in the axonal cytoskeleton interrupt the axoplasmic transport mechanisms, causing the gradual gathering of transport products so as to generate axonal swellings and modifications in neuronal homeostasis. Oxidative stress with consequent impairment of endogenous antioxidant defense mechanisms plays a significant role in the secondary events leading to neuronal death. Studies support the role of an altered axonal calcium homeostasis as a mechanism in the secondary damage of axon, and suggest that calcium channel blocker can alleviate the secondary damage, as well as other mechanisms implied in the secondary injury, and could be targeted as a candidate for therapeutic approaches. Reactive oxygen species (ROS)-mediated axonal degeneration is mainly caused by extracellular Ca²⁺. Increases in the defense mechanisms through the use of exogenous antioxidants may be neuroprotective, particularly if they are given within the neuroprotective time window. A promising potential therapeutic target for DAI is to directly address mitochondria-related injury or to modulate energetic axonal energy failure.

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.

Elevated Serum Protein S100B and Neuron Specific Enolase Values as Predictors of Early Neurological Outcome After Traumatic Brain Injury

BACKGROUND

The objective of our study was to determine the serum concentrations of protein S100B and neuron specific enolase (NSE) as well as their ability and accuracy in the prediction of early neurological outcome after a traumatic brain injury.

METHODS

A total of 130 polytraumatized patients with the associated traumatic brain injuries were included in this prospective cohort study. Serum protein S100B and NSE levels were measured at 6, 24, 48 and 72 hours after the injury. Early neurological outcome was scored by Glasgow Outcome Scale (GOS) on day 14 after the brain injury.

RESULTS

The protein S100B concentrations were maximal at 6 hours after the injury, which was followed by an abrupt fall, and subsequently slower release in the following two days with continual and significantly increased values (p<0.0001) in patients with poor outcome. Secondary increase in protein S100B at 72 hours was recorded in patients with lethal outcome (GOS 1). Dynamics of NSE changes was characterized by a secondary increase in concentrations at 72 hours after the injury in patients with poor outcome.

CONCLUSION

Both markers have good predictive ability for poor neurological outcome, although NSE provides better discriminative potential at 72 hours after the brain injury, while protein S100B has better discriminative potential for mortality prediction.

Fractional anisotropy is a marker in early-stage spinal cord injury

This study was designed to investigate whether fractional anisotropy (FA) contributes to study pathologic changes in SCI. Here rats were divided into a control group and three injury groups. Those in the injury groups were administered a mild, moderate, and severe contusion injury at the T10 vertebral level, respectively. Three rats were randomly selected from each group at 6, 24 and 72h after SCI for imaging examination. Magnetic resonance diffusion tensor imaging was FA and tractography. Once magnetic resonance was completed, blood was collected and serum levels of neuron specific enolase (NSE) and soluble protein-100β (S-100β) were determined. Then animals were sacrificed and histopathologic examination was conducted. The spinal cord in the SCI model rats produced prominent tissue damages characterized by neuronal injury in the affected regions. An obvious decrease in FA happened 24h after SCI, and at 72h, FA tended to be stable. There were significant differences in the serum levels of NSE and S-100β between 6h and 24h, respectively. FA significantly related with the serum testing results at 24h. FA may be used as a marker for different severities of SCI. The optimal time for examination is at 24h post-injury in rat.

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.

Biochemical changes in the injured brain

Brain metabolism is an energy intensive phenomenon involving a wide spectrum of chemical intermediaries. Various injury states have a detrimental effect on the biochemical processes involved in the homeostatic and electrophysiological properties of the brain. The biochemical markers of brain injury are a recent addition in the armamentarium of neuro-clinicians and are being increasingly used in the routine management of neuro-pathological entities such as traumatic brain injury, stroke, subarachnoid haemorrhage and intracranial space occupying lesions. These markers are increasingly being used in assessing severity as well as in predicting the prognostic course of neuro-pathological lesions. S-100 protein, neuron specific enolase, creatinine phosphokinase isoenzyme BB and myelin basic protein are some of the biochemical markers which have been proven to have prognostic and clinical value in the brain injury. While S-100, glial fibrillary acidic protein and ubiquitin C terminal hydrolase are early biomarkers of neuronal injury and have the potential to aid in clinical decision-making in the initial management of patients presenting with an acute neuronal crisis, the other biomarkers are of value in predicting long-term complications and prognosis in such patients. In recent times cerebral microdialysis has established itself as a novel way of monitoring brain tissue biochemical metabolites such as glucose, lactate, pyruvate, glutamate and glycerol while small non-coding RNAs have presented themselves as potential markers of brain injury for future.

A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury

Background

In order to improve injury assessment of brain injuries, protein markers of pathophysiological processes and tissue fate have been introduced in the clinic. The most studied protein “biomarker” of cerebral damage in traumatic brain injury (TBI) is the protein S100B. The aim of this narrative review is to thoroughly analyze the properties and capabilities of this biomarker with focus on clinical utility in the assessment of patients suffering from TBI.

Results

S100B has successfully been implemented in the clinic regionally (1) to screen mild TBI patients evaluating the need to perform a head computerized tomography, (2) to predict outcome in moderate-to-severe TBI patients, (3) to detect secondary injury development in brain-injured patients and (4) to evaluate treatment efficacy. The potential opportunities and pitfalls of S100B in the different areas usually refer to its specificity and sensitivity to detect and assess intracranial injury.

Conclusion

Given some shortcomings that should be realized, S100B can be used as a versatile screening, monitoring and prediction tool in the management of TBI patients.

A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury

BACKGROUND

In order to improve injury assessment of brain injuries, protein markers of pathophysiological processes and tissue fate have been introduced in the clinic. The most studied protein "biomarker" of cerebral damage in traumatic brain injury (TBI) is the protein S100B. The aim of this narrative review is to thoroughly analyze the properties and capabilities of this biomarker with focus on clinical utility in the assessment of patients suffering from TBI.

RESULTS

S100B has successfully been implemented in the clinic regionally (1) to screen mild TBI patients evaluating the need to perform a head computerized tomography, (2) to predict outcome in moderate-to-severe TBI patients, (3) to detect secondary injury development in brain-injured patients and (4) to evaluate treatment efficacy. The potential opportunities and pitfalls of S100B in the different areas usually refer to its specificity and sensitivity to detect and assess intracranial injury.

CONCLUSION

Given some shortcomings that should be realized, S100B can be used as a versatile screening, monitoring and prediction tool in the management of TBI patients.

Biofluid Proteomics and Biomarkers in Traumatic Brain Injury

Traumatic brain injury (TBI) is an injury to the brain caused by an external mechanical force, affecting millions of people worldwide. The disease course and prognosis are often unpredictable, and it can be challenging to determine an early diagnosis in case of mild injury as well as to accurately phenotype the injury. There is currently no cure for TBI-drugs having failed repeatedly in clinical trials-but an intense effort has been put to identify effective neuroprotective treatment. The detection of novel biomarkers, to understand more of the disease mechanism, facilitates early diagnosis, predicts disease progression, and develops molecularly targeted therapies that would be of high clinical interest. Over the last decade, there has been an increasing effort and initiative toward finding TBI-specific biomarker candidates. One promising strategy has been to use state-of-the-art neuroproteomics approaches to assess clinical biofluids and compare the cerebrospinal fluid (CSF) and blood proteome between TBI and control patients or between different subgroups of TBI. In this chapter, we summarize and discuss the status of biofluid proteomics in TBI, with a particular focus on the latest findings.

Biomarkers

Biomarkers are key tools and can provide crucial information on the complex cascade of events and molecular mechanisms underlying traumatic brain injury (TBI) pathophysiology. Obtaining a profile of distinct classes of biomarkers reflecting core pathologic mechanisms could enable us to identify and characterize the initial injury and the secondary pathologic cascades. Thus, they represent a logical adjunct to improve diagnosis, track progression and activity, guide molecularly targeted therapy, and monitor therapeutic response in TBI. Accordingly, great effort has been put into the identification of novel biomarkers in the past 25 years. However, the role of brain injury markers in clinical practice has been long debated, due to inconsistent regulatory standards and lack of reliable evidence of analytical validity and clinical utility. We present a comprehensive overview of the markers currently available while characterizing their potential role and applications in diagnosis, monitoring, drug discovery, and clinical trials in TBI. In reviewing these concepts, we discuss the recent inclusion of brain damage biomarkers in the diagnostic guidelines and provide perspectives on the validation of such markers for their use in the clinic.

Blood biomarkers for brain injury: What are we measuring?

Accurate diagnosis for mild traumatic brain injury (mTBI) remains challenging, as prognosis and return-to-play/work decisions are based largely on patient reports. Numerous investigations have identified and characterized cellular factors in the blood as potential biomarkers for TBI, in the hope that these factors may be used to gauge the severity of brain injury. None of these potential biomarkers have advanced to use in the clinical setting. Some of the most extensively studied blood biomarkers for TBI include S100β, neuron-specific enolase, glial fibrillary acidic protein, and Tau. Understanding the biological function of each of these factors may be imperative to achieve progress in the field. We address the basic question: what are we measuring? This review will discuss blood biomarkers in terms of cellular origin, normal and pathological function, and possible reasons for increased blood levels. Considerations in the selection, evaluation, and validation of potential biomarkers will also be addressed, along with mechanisms that allow brain-derived proteins to enter the bloodstream after TBI. Lastly, we will highlight perspectives and implications for repetitive neurotrauma in the field of blood biomarkers for brain injury.

Functional resting-state fMRI connectivity correlates with serum levels of the S100B protein in the acute phase of traumatic brain injury

The S100B protein is an intra-cellular calcium-binding protein that mainly resides in astrocytes in the central nervous system. The serum level of S100B is used as biomarker for the severity of brain damage in traumatic brain injury (TBI) patients. In this study we investigated the relationship between intrinsic resting-state brain connectivity, measured 1-22 days (mean 8 days) after trauma, and serum levels of S100B in a patient cohort with mild-to-severe TBI in need of neuro-intensive care in the acute phase. In line with previous investigations, our results show that the peak level of S100B acquired during the acute phase of TBI was negatively correlated with behavioral measures (Glasgow Outcome Score, GOS) of functional outcome assessed 6 to 12 months post injury. Using a multi-variate pattern analysis-informed seed-based correlation analysis, we show that the strength of resting-state brain connectivity in multiple resting-state networks was negatively correlated with the peak of serum levels of S100B. A negative correspondence between S100B peak levels recorded 12-36 h after trauma and intrinsic connectivity was found for brain regions located in the default mode, fronto-parietal, visual and motor resting-state networks. Our results suggest that resting-state brain connectivity measures acquired during the acute phase of TBI is concordant with results obtained from molecular biomarkers and that it may hold a capacity to predict long-term cognitive outcome in TBI patients.

S-100 B Concentrations Are a Predictor of Decreased Survival in Patients with Major Trauma, Independently of Head Injury

BACKGROUND

Major trauma remains one of the principle causes of disability and death throughout the world. There is currently no satisfactory risk assessment to predict mortality in patients with major trauma. The aim of our study is to examine whether S-100 B protein concentrations correlate with injury severity and survival in patients with major trauma, with special emphasis on patients without head injury.

METHODS

Our retrospective data analysis comprised adult patients admitted to our emergency department between 1.12. 2008 and 31.12 2010 with a suspected major trauma. S-100 B concentrations were routinely assessed in major trauma patients.

RESULTS

A total of 27.7% (378) of all patients had major trauma. The median ISS was 24.6 (SD 8.4); 16.6% (63/378) of the patients died. S-100 B concentrations correlated overall with the ISS (p<0.0001). Patients who died had significantly higher S-100 B concentrations than survivors (8.2 μg/l versus 2.2 μg/l, p<0.0001). Polytraumatised patients with and without head trauma did not differ significantly with respect to S-100 B concentration (3.2 μg/l (SD 5.3) versus 2.9 μg/l (SD 3.8), respectively, p = 0.63) or with respect to Injury Severity Score (24.8 (SD 8.6) versus 24.2 (SD 8.1), respectively, p = 0.56). S-100 B concentrations correlated negatively with survival (p<0.0001) in all patients and in both subgroups (p = 0.001 and p = 0.006, respectively).

CONCLUSIONS

S-100 concentrations on admission correlate positively with greater injury severity and decreased survival in major trauma patients, independently of the presence of a head injury. S-100 B protein levels at admission in patients with major trauma may therefore be used to assess outcome in all polytraumatised patients. These measurements should be subject to further evaluation.

Current status of fluid biomarkers in mild traumatic brain injury

Mild traumatic brain injury (mTBI) affects millions of people annually and is difficult to diagnose. Mild injury is insensitive to conventional imaging techniques and diagnoses are often made using subjective criteria such as self-reported symptoms. Many people who sustain a mTBI develop persistent post-concussive symptoms. Athletes and military personnel are at great risk for repeat injury which can result in second impact syndrome or chronic traumatic encephalopathy. An objective and quantifiable measure, such as a serum biomarker, is needed to aid in mTBI diagnosis, prognosis, return to play/duty assessments, and would further elucidate mTBI pathophysiology. The majority of TBI biomarker research focuses on severe TBI with few studies specific to mild injury. Most studies use a hypothesis-driven approach, screening biofluids for markers known to be associated with TBI pathophysiology. This approach has yielded limited success in identifying markers that can be used clinically, additional candidate biomarkers are needed. Innovative and unbiased methods such as proteomics, microRNA arrays, urinary screens, autoantibody identification and phage display would complement more traditional approaches to aid in the discovery of novel mTBI biomarkers.

Assessing bicycle-related trauma using the biomarker S100B reveals a correlation with total injury severity

PURPOSE

Worldwide, the use of bicycles, for both recreation and commuting, is increasing. S100B, a suggested protein biomarker for cerebral injury, has been shown to correlate to extracranial injury as well. Using serum levels of S100B, we aimed to investigate how S100B could be used when assessing injuries in patients suffering from bicycle trauma injury. As a secondary aim, we investigated how hospital length of stay and injury severity score (ISS) were correlated to S100B levels.

METHODS

We performed a retrospective, database study including all patients admitted for bicycle trauma to a level 1 trauma center over a four-year period with admission samples of S100B (n = 127). Computerized tomography (CT) scans were reviewed and remaining data were collected from case records. Univariate- and multivariate regression analyses, linear regressions and comparative statistics (Mann-Whitney) were used where appropriate.

RESULTS

Both intra- and extracranial injuries were correlated with S100B levels. Stockholm CT score presented the best correlation of an intracranial parameter with S100B levels (p < 0.0001), while the presences of extremity injury, thoracic injury, and non-cervical spinal injury were also significantly correlated (all p < 0.0001, respectively). A multivariate linear regression revealed that Stockholm CT score, non-cervical spinal injury, and abdominal injury all independently correlated with levels of S100B. Patients with a ISS > 15 had higher S100 levels than patients with ISS < 16 (p < 0.0001). Patients with extracranial, as well as intracranial- and extracranial injuries, had significantly higher levels of S100B than patients without injuries (p < 0.05 and p < 0.01, respectively). The admission serum levels of S100B (log, µg/L) were correlated with ISS (log) (r = 0.53) and length of stay (log, days) (r = 0.45).

CONCLUSIONS

S100B levels were independently correlated with intracranial pathology, but also with the extent of extracranial injury. Length of stay and ISS were both correlated with the admission levels of S100B in bicycle trauma, suggesting S100B to be a good marker of aggregated injury severity. Further studies are warranted to confirm our findings.

Analysis of S100 calcium binding protein B serum levels in different types of traumatic intracranial lesions

The objective of this study was to determine whether the type of intracranial traumatic lesions, the number of simultaneous traumatic lesions, and the occurrence of skull and facial bone fractures have an influence on S100 calcium binding protein B (S100B) serum levels. Patients with blunt traumatic brain injury were prospectively enrolled into this cohort study over a period of 13 months. Venous blood samples were obtained prior to emergency cranial CT scan in all patients within 3 h after injury. The patients were then assigned into six groups: 1) concussion, 2) epidural hematoma, 3) subdural hematoma, 4) subarachnoid hemorrhage, 5) brain contusions, and 6) brain edema. The study included 1696 head trauma patients with a mean age of 57.7 ± 25.3 years, and 126 patients (8%) had 182 traumatic lesions on CT. Significant differences in S100B serum levels were found between cerebral edema and the other four bleeding groups: epidural p = 0.0002, subdural p < 0.0001, subarachnoid p = 0.0001, brain contusions p = 0.0003, and concussion p < 0.0001. Significant differences in S100B values between patients with one or two intracranial lesions (p = 0.014) or with three (p < 0.0001) simultaneous intracranial lesions were found. In patients with intracranial traumatic lesions, skull fractures, as well as skull and facial bone fractures occurring together, were identified as significant additional factors for the increase in serum S100B levels (p < 0.0001). Older age was also associated with elevated S100B serum levels (p < 0.0001). Our data show that peak S100B serum levels were found in patients with cerebral edema and brain contusions.

A Role of Serum-Based Neuronal and Glial Markers as Potential Predictors for Distinguishing Severity and Related Outcomes in Traumatic Brain Injury

Objective

Optimal treatment decision and estimation of the prognosis in traumatic brain injury (TBI) is currently based on demographic and clinical predictors. But sometimes, there are limitations in these factors. In this study, we analyzed three central nervous system biomarkers in TBI patients, will discuss the roles and clinical applications of biomarkers in TBI.

Methods

From July on 2013 to August on 2014, a total of 45 patients were included. The serum was obtained at the time of hospital admission, and biomarkers were extracted with centrifugal process. It was analyzed for the level of S-100 beta (S100B), glial fibrillary acidic protein (GFAP), and ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1).

Results

This study included 33 males and 12 females with a mean age of 58.5 (19-84) years. TBI patients were classified into two groups. Group A was severe TBI with Glasgow Coma Scale (GCS) score 3-5 and Group B was mild TBI with GCS score 13-15. The median serum concentration of S100B, GFAP, and UCH-L1 in severe TBI were raised 5.1 fold, 5.5 fold, and 439.1 fold compared to mild injury, respectively. The serum levels of these markers correlated significantly with the injury severity and clinical outcome (p<0.001). Increased level of markers was strongly predicted poor outcomes.

Conclusion

S100B, GFAP, and UCH-L1 serum level of were significantly increased in TBI according to severity and associated clinical outcomes. Biomarkers have potential utility as diagnostic, prognostic, and therapeutic adjuncts in the setting of TBI.

Emerging themes from the literature on circulating biomarkers of traumatic brain injury

ABSTRACT 

Objective diagnosis of traumatic brain injury (TBI) and early prediction of TBI-associated outcome remains a significant clinical challenge with major public health implications. The use of circulating biomarkers to quantify TBI has promise for real-time clinical decision making and may help clinicians determine the need for advanced imaging, and guide an individualized approach to the management of TBI. In this review of the literature, we provide an overview of candidate TBI biomarkers and discuss several themes emerging from the literature on TBI biomarkers. We suggest that the future utility of TBI biomarkers lies in the creation of composite panels of biomarkers tailored to the pursuit of specific clinic questions.

A novel, ultrasensitive assay for tau: potential for assessing traumatic brain injury in tissues and biofluids

Traumatic brain injury (TBI) is a cause of death and disability and can lead to tauopathy-related dementia at an early age. Pathologically, TBI results in axonal injury that is coupled to tau hyperphosphorylation, leading to microtubule instability and tau-mediated neurodegeneration. This suggests that the forms of this protein might serve as neuroinjury-related biomarkers for diagnosis of injury severity and prognosis of the neurological damage prior to clinical expression. We initially determined whether we could detect tau in body fluids using a highly sensitive assay. We used a novel immunoassay, enhanced immunoassay using multi-arrayed fiberoptics (EIMAF) either alone or in combination with rolling circle amplification (a-EIMAF) for the detection of total (T) and phosphorylated (P) tau proteins from brains and biofluids (blood, CSF) of rodents following controlled cortical impact (CCI) and human patients post severe TBI (sTBI). This assay technology for tau is the most sensitive to date with a detection limit of approximately 100 ag/mL for either T-tau and P-tau. In the rodent models, T-tau and P-tau levels in brain and blood increased following CCI during the acute phase and remained high during the chronic phase (30 d). In human CSF samples, T-tau and P-tau increased during the sampling period (5-6 d). T-tau and P-tau in human serum rose during the acute phase and decreased during the chronic stage but was still detectable beyond six months post sTBI. Thus, EIMAF has the potential for assessing both the severity of the proximal injury and the prognosis using easily accessible samples.

Association of ICP, CPP, CT findings and S-100B and NSE in severe traumatic head injury. Prognostic value of the biomarkers

OBJECTIVE

The association was studied of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) on S-100B and neuron-specific enolase (NSE) in severe traumatic brain injury (sTBI). The relationship was explored between biomarkers, ICP, CPP, CT-scan classifications and the clinical outcome.

MATERIALS AND METHODS

Data were collected prospectively and consecutively in 48 patients with Glasgow Coma Scale score ≤ 8, age 15-70 years. NSE and S-100B were analysed during 5 consecutive days. The initial and follow-up CT-scans were classified according to the Marshall, Rotterdam and Morris-Marshall classifications. Outcome was evaluated with extended Glasgow outcome scale at 3 months.

RESULTS

Maximal ICP and minimal CPP correlated with S-100B and NSE levels. Complex relations between biomarkers and CT classifications were observed. S-100B bulk release (AUC = 0.8333, p = 0.0009), and NSE at 72 hours (AUC = 0.8476, p = 0.0045) had the highest prediction power of mortality. Combining Morris-Marshall score and S-100B bulk release improved the prediction of clinical outcome (AUC = 0.8929, p = 0.0008).

CONCLUSION

Biomarker levels are associated with ICP and CPP and reflect different aspects of brain injury as evaluated by CT-scan. The biomarkers might predict mortality. There are several pitfalls influencing the interpretation of biomarker data in respect to ICP, CPP, CT-findings and clinical outcome.

Quercetin Administration After Spinal Cord Trauma Changes S-100β Levels

Background:

It has been shown previously that S-100β levels in serum correspond with the severity of central nervous system (CNS) trauma. It also has been suggested that S-100β in CNS tissue is involved in neuroprotection and neuroregeneration. We have previously shown that administration of quercetin results in improved motor function in an animal model of spinal cord trauma.

Methods:

Mid-thoracic spinal cord compression injury was produced in adult maleWistar rats. Serum and tissue samples were acquired from quercetin-treated animals (25 μmol / kg) and saline controls at 6, 12 and 24 hours after the trauma. S-100β levels were measured using a luminometric assay in the damaged tissue and in the serum of the animals.

Results:

The increase in serum S-100β levels seen in saline controls after spinal cord trauma was ameliorated in the quercetin-treated animals at all time points, although the difference to saline controls became statistically significant only at 24 hrs after the trauma. Compared to tissue S-100β levels in healthy animals, values were significantly decreased in saline controls at all three time points, while they were decreased at 6 hrs and increased at both 12 and 24 hrs in quercetin-treated animals. At all three time points tissue S-100β levels were significantly higher in quercetin-treated animals than in saline controls.

Conclusions:

Administration of quercetin results in modification of S-100β levels in the setting of experimental spinal cord trauma. The kinetic patterns of the S-100β fluctuations in serum and tissue suggest that post-traumatic administration of quercetin decreases the extent of CNS injury.

Can Admission S-100β Predict the Extent of Brain Damage in Head Trauma Patients?

Background:

As has been shown previously, S-100β levels in serum can be a useful predictor of brain damage after head trauma. This pilot study was designed to investigate whether urine samples, which are much easier to obtain, could be used for the same purpose instead of serum samples.

Methods:

Ninety-six consecutive patients admitted with head trauma were recruited in the study. After exclusion of 54 patients, mostly because of significant additional trauma, S-100β levels were analyzed in serum and urine of 42 patients using a luminometric assay. A range for normal values was established based on samples from ten healthy volunteers.

Results:

S-100β serum levels increased proportional to the severity of the head trauma, as had been previously shown by several other groups. In many patients, initial increases in urine S-100β levels were seen later than in serum, after which the kinetics of S-100β levels in urine seemed to follow that established for serum levels. S-100β values in urine were on average about 54% lower in urine than in serum.

Conclusions:

S-100β levels in urine obtained on admission to the hospital are not a good indicator for the extent of brain damage. However, urine S-100β levels obtained at later time points might be a useful indicator for the development of secondary brain injury.

The Relationship of Serum S100B Levels with Infarction Size and Clinical Outcome in Acute Ischemic Stroke Patients

INTRODUCTION

S100B protein, which helps nerve development and differentiation, is produced by astrocytes and can be detected in peripheral circulation after brain damage. In this study, we aimed to investigate the relationship between the serum S100B protein level and the infarction volume and clinical outcome and also the early prognostic role of serum S100B protein in patients with ischemic stroke.

METHOD

Fifty patients admitted in the first 24-hour period of acute ischemic stroke were evaluated prospectively, and the findings were compared to those of the controls (n=26). S100B levels of the patients and neurological findings on days 1, 3, and 5 and their functional outcomes on the discharge day and at the first month were recorded by the same examiner.

RESULTS

S100B levels were not affected by sex, age, or concomitant systemic diseases. The maximum levels of S100B were recorded on the 3^rd day, and there was a correlation between infarct size and S100B levels. No correlation between the severity of stroke and S100B level was found. There was a poor correlation between the functional outcomes of the patients at the 1^st month and S100B levels and on the 3^rd day.

CONCLUSION

The detection of high S100B levels in peripheral circulation after acute ischemic stroke and the correlations of S100B levels with infarct size (good) and disability (poor) imply that S100B protein may be used as a peripheral marker in acute ischemic stroke patients.

Elevated cell-free plasma DNA level as an independent predictor of mortality in patients with severe traumatic brain injury

Trauma is the leading cause of death in individuals less than 45 years old worldwide, and up to 50% of trauma fatalities are because of brain injury. Prediction of outcome is one of the major problems associated with severe traumatic brain injury (TBI), and research efforts have focused on the investigation of biomarkers with prognostic value after TBI. Therefore, our aim was to investigate whether cell-free DNA concentrations correlated to short-term primary outcome (survival or death) and Glasgow Coma Scale (GCS) scores after severe TBI. A total of 188 patients with severe TBI were enrolled in this prospective study; outcome variables comprised survival and neurological assessment using the GCS at intensive care unit (ICU) discharge. Control blood samples were obtained from 25 healthy volunteers. Peripheral venous blood was collected at admission to the ICU. Plasma DNA was measured using a real-time quantitative polymerase chain reaction (PCR) assay for the β-globin gene. There was correlation between higher DNA levels and both fatal outcome and lower hospital admission GCS scores. Plasma DNA concentrations at the chosen cutoff point (≥171,381 kilogenomes-equivalents/L) predicted mortality with a specificity of 90% and a sensitivity of 43%. Logistic regression analysis showed that elevated plasma DNA levels were independently associated with death (p<0.001). In conclusion, high cell-free DNA concentration was a predictor of short-term mortality after severe TBI.

Post-traumatic hypoxia is associated with prolonged cerebral cytokine production, higher serum biomarker levels, and poor outcome in patients with severe traumatic brain injury

Secondary hypoxia is a known contributor to adverse outcomes in patients with traumatic brain injury (TBI). Based on the evidence that hypoxia and TBI in isolation induce neuroinflammation, we investigated whether TBI combined with hypoxia enhances cerebral cytokine production. We also explored whether increased concentrations of injury biomarkers discriminate between hypoxic (Hx) and normoxic (Nx) patients, correlate to worse outcome, and depend on blood-brain barrier (BBB) dysfunction. Forty-two TBI patients with Glasgow Coma Scale ≤8 were recruited. Cerebrospinal fluid (CSF) and serum were collected over 6 days. Patients were divided into Hx (n=22) and Nx (n=20) groups. Eight cytokines were measured in the CSF; albumin, S100, myelin basic protein (MBP) and neuronal specific enolase (NSE) were quantified in serum. CSF/serum albumin quotient was calculated for BBB function. Glasgow Outcome Scale Extended (GOSE) was assessed at 6 months post-TBI. Production of granulocye macrophage-colony stimulating factor (GM-CSF) was higher, and profiles of GM-CSF, interferon (IFN)-γ and, to a lesser extent, tumor necrosis factor (TNF), were prolonged in the CSF of Hx but not Nx patients at 4-5 days post-TBI. Interleukin (IL)-2, IL-4, IL-6, and IL-10 increased similarly in both Hx and Nx groups. S100, MBP, and NSE were significantly higher in Hx patients with unfavorable outcome. Among these three biomarkers, S100 showed the strongest correlations to GOSE after TBI-Hx. Elevated CSF/serum albumin quotients lasted for 5 days post-TBI and displayed similar profiles in Hx and Nx patients. We demonstrate for the first time that post-TBI hypoxia is associated with prolonged neuroinflammation, amplified extravasation of biomarkers, and poor outcome. S100 and MBP could be implemented to track the occurrence of post-TBI hypoxia, and prompt adequate treatment.