Role of serum S100B as an early predictor of high intracranial pressure and mortality in brain injury: a pilot study

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.

Prognostic properties of the association between the S‑100B protein levels and the mean cerebral blood flow velocity in patients diagnosed with severe traumatic brain injury

Craniocerebral injury (CBI) is tissue damage caused by a sudden mechanical force. CBI can result in neurological, neuropsychological and psychiatric dysfunctions. Currently, the severity of CBI is assessed using the Glasgow Coma Scale, brain perfusion pressure measurements, transcranial Doppler tests and biochemical markers. This study aimed to determine the applicability of the S-100B protein levels and the time-averaged mean maximum cerebral blood flow velocity (V_mean) as a means of predicting the treatment outcomes of CBI in the first 4 days of hospitalization. The results validated the standard reference ranges previously proposed for the concentration of S-100B (0.05-0.23 µg/l) and the mean of cerebral blood flow velocity (30.9 to 74.1 cm/sec). The following stratification scheme was used to predict the success of treatment: Patients with a Glasgow Outcome Scale (GOS) score ≥4 or GOS <4 were stratified into ‘favorable’ and ‘unfavorable’ groups, respectively. The favorable group showed relatively constant levels of the S-100B protein close to the normal range and exhibited an increase in V_mean, but this was still within the normal range. The unfavorable group exhibited a high level of S-100B protein and increased V_mean outside of the normal ranges. The changes in the levels of S-100B in the unfavorable and favorable groups were -0.03 and -0.006 mg/l/h, respectively. Furthermore, the rate of decrease in the V_mean value in the unfavorable and favorable groups were -0.26 and -0.18 cm/sec/h, respectively. This study showed that constant levels of S-100B protein, even slightly above the normal range, associated with an increase in V_mean was indicative of a positive therapeutic outcome. However, additional research is required to obtain the appropriate statistical strength required for clinical practice.

Effects of Yunanan Baiyao adjunct therapy on postoperative recovery and clinical prognosis of patients with traumatic brain injury: A randomized controlled trial

BACKGROUND

Effective therapies are needed to prevent the secondary injury and poor prognosis associated with emergency craniotomy of traumatic brain injury (TBI).

HYPOTHESIS/PURPOSE

The wound-healing medicine Yunnan Baiyao (YB) and Xingnaojing (XNJ) adjunct-therapy may improve the outcome of orthodox mono-therapy (OT).

STUDY DESIGN

Randomized controlled trial.

METHODS

Eighty patients with moderate-to-severe TBI received emergency craniotomy (within 12 h after TBI) at the Chinese PLA General Hospital before being randomly assigned to 4 different treatments (n = 20) for 7 days: 1) OT; 2) OT+XNJ (i.v. 20 ml/daily); 3) OT+low dose-YB (oral, 1,000 mg/day); 4) OT+high dose-YB, 2,000 mg/day).

RESULTS

GCS score was improved more quickly and became significantly higher in XNJ, l-YB, h-YB groups than in OT group (p<0.01). Serum S100B peaked higher but declined more slowly in OT group than in other groups (p<0.01). On postoperative Day 7, S100B was 20% below baseline in YB and XNJ groups but remained 19% above baseline in OT group which also lost 38% of superoxide dismutase (SOD) activity on Day 3 and recovered 69% of SOD on Day 7 whereas the YB and XNJ groups lost 16%∼23% of SOD activity on Day 3 and recovered 92%∼99% of SOD on Day 7 (p<0.01). Clinical prognosis (Glasgow Outcome Scale and Karnofsky Performance Scale) were significantly better (25%∼30%) in the XNJ, l-YB and h-YB groups than in OT group 3 months post-surgery and were correlated with serum S100B and SOD.

CONCLUSIONS

YB and XNJ adjunct therapies improved postoperative recovery and clinical prognosis in patients with moderate-to-severe TBI partly through divergent regulation of S100B and SOD pathways. (The trial was registered at Chinese Clinical Trial Registry (ChiCTR) trial registration number: ChiCTR2000030280).

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.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Hepatic Encephalopathy in Children With Acute Liver Failure: Utility of Serum Neuromarkers

BACKGROUND

Pediatric acute liver failure (PALF) is a public heath burden, often requiring prolonged hospitalization and liver transplantation. Hepatic encephalopathy (HE) is a complication of PALF with limited diagnostic tools to predict outcomes. Serum neurological markers (neuron-specific enolase, S100β, and myelin basic protein) can be elevated in traumatic or ischemic brain injury. We hypothesized that these neuromarkers would be associated with the development of HE in PALF.

METHODS

PALF study participants enrolled between May 2012 and December 2014 by 12 participating centers were the subjects of this analysis. Daily HE assessments were determined by study investigators. Neurological and inflammatory markers were measured using enzyme-linked immunosorbent assay and MILLIPLEX techniques, respectively. To model encephalopathy, these markers were log2 transformed and individually examined for association with HE using a generalized linear mixed model with a logit link and random intercept.

RESULTS

Eighty-two children had neurological and inflammatory marker levels and HE assessments recorded, with the majority having assessments for 3 days during their illness. An indeterminate diagnosis (29%) was most common and the median age was 2.9 years. Significant associations were observed for HE with S100β (odds ratio 1.16, 95% confidence interval [1.03-1.29], P = 0.04) and IL-6 (odds ratio 1.24 [1.11-1.38], P = 0.006).

CONCLUSIONS

Serum S100β and IL-6 are associated with HE in children with PALF. Measuring these markers may assist in assessing neurological injury in PALF, impacting clinical decisions.

A subset of calcium-binding S100 proteins show preferential heterodimerization

The assembly of proteins into dimers and oligomers is a necessary step for the proper function of transcription factors, muscle proteins, and proteases. In uncontrolled states, oligomerization can also contribute to illnesses such as Alzheimer's disease. The S100 protein family is a group of dimeric proteins that have important roles in enzyme regulation, cell membrane repair, and cell growth. Most S100 proteins have been examined in their homodimeric state, yet some of these important proteins are found in similar tissues implying that heterodimeric molecules can also be formed from the combination of two different S100 members. In this work, we have established co-expression methods in order to identify and quantify the distribution of homo- and heterodimers for four specific pairs of S100 proteins in their calcium-free states. The split GFP trap methodology was used in combination with other GFP variants to simultaneously quantify homo- and heterodimeric S100 proteins in vitro and in living cells. For the specific S100 proteins examined, NMR, mass spectrometry, and GFP trap experiments consistently show that S100A1:S100B, S100A1:S100P, and S100A11:S100B heterodimers are the predominant species formed compared to their corresponding homodimers. We expect the tools developed here will help establish the roles of S100 heterodimeric proteins and identify how heterodimerization might alter the specificity for S100 protein action in cells.

Serum S100B levels in patients with depression

BACKGROUND

The biochemical basis of depression has been related to blood-brain barrier (BBB) allowing/restricting a number of components to enter the brain milieu from the peripheral plasma milieu. S100B has been associated with BBB damage and is used as a marker of its integrity. Several studies have reported that depressive patients have increased levels of S100B in serum and cerebrospinal fluid.

MATERIALS AND METHODS

Forty-two confirmed cases of depression, 13-25 years of ages were recruited from the Department of Psychiatry, All India Institute of Medical Sciences during the period from January 2013 to June 2014 along with 42 healthy controls of comparable age and sex. Psychometric evaluation of the patients and controls was done to assess the severity of depression using Beck's Depression Inventory-II and Hamilton Depression Rating Scale. Medical assessment and laboratory investigations were done. Serum S100B levels were measured using Sandwich ELISA. The results obtained were statistically analyzed.

RESULTS

Levels of serum S100B were significantly elevated in patients with major depression as compared to controls. Significantly higher levels of S100B were seen only in females as compared to their healthy counterparts. Serum S100B was higher in depressed participants with the recurrent disorder than those with single episode. No correlation of levels of this marker was seen with clinical severity of the patients. It was found that with increased duration of illness for which the patient was being treated with antidepressants, the patients had higher levels of S100B.

CONCLUSIONS

Serum S100B can be used as a biomarker of depression.

Plasma D-dimer safely reduces unnecessary CT scans obtained in the evaluation of pediatric head trauma

PURPOSE

Serum D-dimer has been proposed as a biomarker to aid in the diagnosis of pediatric traumatic brain injury (TBI). We investigated the accuracy of D-dimer in predicting the absence of TBI and evaluated the degree by which D-dimer could limit unnecessary computed tomography scans of the head (CTH).

METHODS

Retrospective review of patients with suspected TBI from 2011 to 2013 who underwent evaluation with CTH and quantitative D-dimer. D-dimer levels were compared among patients with clinically-important TBI (ciTBI), TBI, isolated skull fracture and no injury.

RESULTS

Of the 663 patients evaluated for suspected TBI, ciTBI was identified in 116 (17.5%), TBI in 77 (11.6%), skull fracture in 61 (9.2%) and no head injury in 409 (61.7%). Patients with no head injury had significantly lower D-dimer values (1531±1791pg/μL) compared to those with skull fracture, TBI and ciTBI (2504±1769, 2870±1633 and 4059±1287pg/μL, respectively, p<0.005). Using a D-dimer value <750pg/μL as a negative screen, no ciTBIs would be missed and 209 CTHs avoided (39.7% of total).

CONCLUSION

Low plasma D-dimer predicts the absence of ciTBI for pediatric patient with suspected TBI. Incorporating D-dimer into current diagnostic algorithms may significantly limit the number of unnecessary CTHs performed in this population.

TYPE OF STUDY

Study of diagnostic test.

LEVEL OF EVIDENCE

I.

Biomarkers Associated with the Outcome of Traumatic Brain Injury Patients

This review focuses on biomarkers associated with the outcome of traumatic brain injury (TBI) patients, such as caspase-3; total antioxidant capacity; melatonin; S100B protein; glial fibrillary acidic protein (GFAP); glutamate; lactate; brain-derived neurotrophic factor (BDNF); substance P; neuron-specific enolase (NSE); ubiquitin carboxy-terminal hydrolase L-1 (UCH-L1); tau; decanoic acid; and octanoic acid.

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.

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.

S100B and Neuron-Specific Enolase as mortality predictors in patients with severe traumatic brain injury

OBJECTIVE

To determine temporal profile and prognostic ability of S100B protein and neuron-specific enolase (NSE) for prediction of short/long-term mortality in patients suffering from severe traumatic brain injury (sTBI).

METHODS

Ninety-nine patients with sTBI were included in the study. Blood samples were drawn on admission and on subsequent 24, 48, 72, and 96 h.

RESULTS

15.2% of patients died in NeuroCritical Care Unit, and 19.2% died within 6 months of the accident. S100B concentrations were significantly higher in patients who died compared to survivors. NSE levels were different between groups just at 48 h. In the survival group, S100B levels decreased from 1st to 5th sample (p < 0.001); NSE just from 1st to 3rd (p < 0.001) and then stabilized. Values of S100B and NSE in non-survival patients did not significantly vary over the four days post sTBI. ROC-analysis showed that all S100B samples were useful tools for predicting mortality, the best the 72 h sample (AUC 0.848 for discharge mortality, 0.855 for six-month mortality). NSE ROC-analysis indicated that just the 48-h sample predicted mortality (AUC 0.733 for discharge mortality, 0.720 for six-month mortality).

CONCLUSION

S100B protein showed higher prognostic capacity than NSE to predict short/long-term mortality in sTBI patients.

Secondary peaks of S100B in serum relate to subsequent radiological pathology in traumatic brain injury

INTRODUCTION

Patients suffering from severe traumatic brain injury (TBI) often develop secondary brain lesions that may worsen outcome. S100B, a biomarker of brain damage, has been shown to increase in response to secondary cerebral deterioration. The aim of this study was to analyze the occurrence of secondary increases in serum levels of S100B and their relation to potential subsequent radiological pathology present on CT/MRI-scans.

METHODS

Retrospective study from a trauma level 1 hospital, neuro-intensive care unit. 250 patients suffering from TBI were included. Inclusion required a minimum of two radiological examinations and at least three serum samples of S100B, with at least one >48 h after trauma.

RESULTS

Secondary pathological findings on CT/MRI, present in 39 % (n = 98) of the patients, were highly correlated to secondary increases of ≥0.05 μg/L S100B (P < 0.0001, pseudo-R (2) 0.532). Significance remained also after adjusting for known important TBI predictors. In addition, secondary radiological findings were significantly correlated to outcome (Glasgow Outcome Score, GOS) in uni-(P < 0.0001, pseudo-R (2) 0.111) and multivariate analysis. The sensitivity and specificity of detecting later secondary radiological findings was investigated at three S100B cut-off levels: 0.05, 0.1, and 0.5 μg/L. A secondary increase of ≥0.05 μg/L had higher sensitivity (80 %) but lower specificity (89 %), compared with a secondary increase of ≥0.5 μg/L (16 % sensitivity, 98 % specificity), to detect secondary radiological findings.

CONCLUSIONS

Secondary increases in serum levels of S100B, even as low as ≥0.05 μg/L, beyond 48 h after TBI are strongly correlated to the development of clinically significant secondary radiological findings.

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.

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.

Serum biomarkers of brain injury to classify outcome after pediatric cardiac arrest*

OBJECTIVES

Morbidity and mortality in children with cardiac arrest largely result from neurologic injury. Serum biomarkers of brain injury can potentially measure injury to neurons (neuron-specific enolase), astrocytes (S100b), and axons (myelin basic protein). We hypothesized that serum biomarkers can be used to classify outcome from pediatric cardiac arrest.

DESIGN

Prospective observational study.

SETTING

Single tertiary pediatric hospital.

PATIENTS

Forty-three children with cardiac arrest.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured serum neuron-specific enolase, S100b, and myelin basic protein on days 1-4 and 7 after cardiac arrest. We recorded demographics, details of the cardiac arrest and resuscitation, and Pediatric Cerebral Performance Category at hospital discharge and 6 months. We analyzed the association of biomarker levels at 24, 48, and 72 hours with favorable (Pediatric Cerebral Performance Category 1-3) or unfavorable (Pediatric Cerebral Performance Category 4-6) outcome and mortality. Forty-three children (49% female; mean age of 5.9 ± 6.3) were enrolled and 17 (40%) died. Serum S100b concentrations peaked earliest, followed by neuron-specific enolase and finally myelin basic protein. Serum neuron-specific enolase and S100b concentrations were increased in the unfavorable versus favorable outcome group and in subjects who died at all time points (all p < 0.05). Serum myelin basic protein at 24 and 72 hours correctly classified survival but not good versus poor outcome. Using best specificity, serum S100b and neuron-specific enolase had optimal positive and negative predictive values at 24 hours to classify both favorable versus unfavorable outcome and survival, whereas serum myelin basic protein's best accuracy occurred at 48 hours. Receiver operator curves for serum S100b and neuron-specific enolase to classify favorable versus unfavorable outcome at 6 months were superior to clinical variables.

CONCLUSIONS

Preliminary data show that serum S100b, neuron-specific enolase, and myelin basic protein may aid in outcome classification of children surviving cardiac arrest.

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.

S100B protein may detect brain death development after severe traumatic brain injury

Despite improvements in the process of organ donation and transplants, the number of organ donors is progressively declining in developed countries. Therefore, the early detection of patients at risk for brain death (BD) is a priority for transplant teams seeking more efficient identification of potential donors. In the extensive literature on S100B as a biomarker for traumatic brain injury (TBI), no evidence appears to exist on its prognostic capacity as a predictor of BD after severe TBI. The objective of this study is to assess the value of including acute S100B levels in standard clinical data as an early screening tool for BD after severe TBI. This prospective study included patients with severe TBI (Glasgow Coma Scale score [GCS] ≤ 8) admitted to our Neurocritical Care Unit over a 30 month period. We collected the following clinical variables: age, gender, GCS score, pupillary alterations at admission, hypotension and pre-hospital desaturation, CT scan results, isolated TBI or other related injuries, Injury Severity Score (ISS), serum S100B levels at admission and 24 h post-admission, and a final diagnosis regarding BD. Of the 140 patients studied, 11.4% developed BD and showed significantly higher S100B concentrations (p<0.001). Multivariate analysis showed that bilateral unresponsive mydriasis at admission and serum S100B at 24 h post-admission had odds ratios (ORs) of 21.35 (p=0.005) and 4.9 (p=0.010), respectively. The same analysis on patients with photomotor reflex in one pupil at admission left only the 24 h S100B sample in the model (OR=15.5; p=0.009). Receiver operating characteristics (ROC) curve analysis on this group showed the highest area under the curve (AUC) (0.86; p=0.001) for 24 h S100B determinations. The cut off was set at 0.372 μg/L (85.7% sensitivity, 79.3% specificity, positive predictive value [PPV]=18.7% and negative predictive value [NPV]=98.9%). This study shows that pupillary responsiveness at admission, as well as 24 h serum S100B levels, could serve as screening tools for the early detection of patients at risk for BD after severe TBI.

Comparison of predictive powers of S100B and cell-free plasma DNA values in intensive care unit patients with intracranial hemorrhage

PURPOSE

To investigate predictive powers of S100B and cell-free DNA (cfDNA) levels in patients in the intensive care unit (ICU) who have with intracranial hemorrhage (ICH) for prognosis.

METHODS

Ninety-nine patients diagnosed with ICH were included in the study. The blood samples were drawn on the day of admittance to ICU and again on the third day. Duration of stay in the ICU and mortality were recorded.

RESULTS

A positive correlation was determined between the values of S100B and cfDNA from both the analysis and the Acute Physiology and Chronic Health Evaluation II scores. For all patients, there was a positive correlation between the duration of stay in the ICU and the values of S100B and cfDNA on the third day. The levels of both S100B and cfDNA in patients who died in the ICU were significantly higher than of those who survived on the day of admittance.

CONCLUSIONS

Both S100B and cfDNA values can be used as markers to predict the prognosis of ICU patients with ICH. However, S100B is more powerful for predicting the prognosis.

S100B is an important outcome predictor in traumatic brain injury

The objective of the study was to examine how S100B, a biomarker of traumatic brain injury (TBI), contributes to outcome prediction after adjusting for known parameters, including age, Glasgow Coma Scale (GCS), pupil reaction, and computed tomography (CT) variables; to examine which parameters have the best correlation to elevated serum levels of S100B; and to investigate when to sample S100B to achieve the strongest association to outcome. This retrospective study included 265 patients with TBI admitted to the neurointensive care unit, Karolinska University Hospital Solna, Stockholm, Sweden. Univariate and multivariate proportional odds regressions were performed to determine parameters most closely related to outcome, and how S100B adds to prediction accuracy. Age (p<0.0001), pupil reaction (p<0.0001), and levels of S100B (p<0.0001) had the strongest statistical correlation to outcome. The area under curve of S100B, the first 48 h after trauma, yielded an additional explained variance of 6.6% in excess of known outcome parameters, including age, GCS, pupil reaction, and CT variables, themselves exhibiting an explained variance of 29.3%. S100B adds substantial information regarding patient outcome, in excess of that provided by known parameters. Only CT variables were found to be significant predictors of increased levels of S100B in uni- and multivariate analysis. Early samples of S100B, within 12 h after trauma, appear to have little prognostic value, and S100B should likely be sampled 12-36 h following trauma to best enhance TBI outcome prediction.

Protein S100B in Traumatic Brain Injury

Protein S100B is a small calcium-binding protein expressed in astroglial cells in the central nervous system. Its concentration increases in cerebrospinal fluid and blood after traumatic brain injury. There are several commercially available methods for analyzing serum S100B. The clinical use of serum S100B is mainly in minor head injury, as a complement to existing guidelines in order to help clinicians to determine who could safely be discharged without a previous CT scan. S100B in severe TBI is still being studied as a marker for secondary neurological complications, but has not yet had an impact in this specific area. Recent research on the clinical use of S100B in pediatric TBI has shown promising results, and the introduction of S100B in minor head injuries could have even greater impact than for adults. However, more research needs to be done before a biomarker can be clinically used in pediatric TBI.

Change in plasma gelsolin level after traumatic brain injury

BACKGROUND

Plasma gelsolin depletion has been associated with poor outcome of critically ill patients. However, there is a paucity of data available on circulating plasma gelsolin concentration in traumatic brain injury (TBI). Thus, we sought to investigate change in plasma gelsolin level after TBI and to evaluate its relation with disease outcome.

METHODS

Fifty healthy controls and 94 patients with acute severe TBI were included. Plasma samples were obtained on admission and at days 1, 2, 3, 5, and 7. Its concentration was measured by enzyme-linked immunosorbent assay.

RESULTS

Twenty-six patients (27.7%) died from TBI in a month. After TBI, plasma gelsolin level in patients decreased during the 6-hour period immediately, was at the nadir in 24 hours, increased gradually thereafter, and was substantially lower than that in healthy controls during the 7-day period. A multivariate analysis showed plasma gelsolin level was an independent predictor for 1-month mortality (odds ratio, 0.941; 95% confidence interval, 0.895– 0.989; p = 0.017) and positively associated with Glasgow Coma Scale (GCS) score (t = 6.538, p 0.001). A receiver operating characteristic curve identified that a baseline plasma gelsolin level 52.7 mg/L predicted 1-month mortality with 88.5% sensitivity and 79.4% specificity (area under the curve, 0.869; 95%confidence interval, 0.783– 0.930). The predictive value of the gelsolin concentration was thus similar to that of GCS scores (p =0.185). However, gelsolin did not statistically significantly improve the area under the curve of GCS scores (p = 0.517).

CONCLUSIONS

Decreased plasma gelsolin level is associated with GCS scores and an independent prognostic marker of mortality after TBI. Reversing plasma gelsolin deficiency may be an effective treatment for TBI.

CSF-biomarkers in Olympic boxing: diagnosis and effects of repetitive head trauma

Background

Sports-related head trauma is common but still there is no established laboratory test used in the diagnostics of minimal or mild traumatic brain injuries. Further the effects of recurrent head trauma on brain injury markers are unknown. The purpose of this study was to investigate the relationship between Olympic (amateur) boxing and cerebrospinal fluid (CSF) brain injury biomarkers.

Methods

The study was designed as a prospective cohort study. Thirty Olympic boxers with a minimum of 45 bouts and 25 non-boxing matched controls were included in the study. CSF samples were collected by lumbar puncture 1–6 days after a bout and after a rest period for at least 14 days. The controls were tested once. Biomarkers for acute and chronic brain injury were analysed.

Results

NFL (mean ± SD, 532±553 vs 135±51 ng/L p = 0.001), GFAP (496±238 vs 247±147 ng/L p<0.001), T-tau (58±26 vs 49±21 ng/L p<0.025) and S-100B (0.76±0.29 vs 0.60±0.23 ng/L p = 0.03) concentrations were significantly increased after boxing compared to controls. NFL (402±434 ng/L p = 0.004) and GFAP (369±113 ng/L p = 0.001) concentrations remained elevated after the rest period.

Conclusion

Increased CSF levels of T-tau, NFL, GFAP, and S-100B in >80% of the boxers demonstrate that both the acute and the cumulative effect of head trauma in Olympic boxing may induce CSF biomarker changes that suggest minor central nervous injuries. The lack of normalization of NFL and GFAP after the rest period in a subgroup of boxers may indicate ongoing degeneration. The recurrent head trauma in boxing may be associated with increased risk of chronic traumatic brain injury.

Biomarkers in neurocritical care

The gold standard for assessing neurological function is the bedside clinical examination. However, in neurocritical patients, the signs and symptoms related to the severity of illness can often be ambiguous. It can be hard to distinguish between a severe but stable disease state and one that is dynamic and in a critical decline. Clinicians and family members alike may struggle with the uncertainty of functional outcome prediction. Intermediate biomarkers of brain injury can assist with ongoing clinical management of patients, and in some circumstances can guide prognosis. Used in the right setting, biomarkers in neurocritical care can also aid with decisions to intensify treatment or avoid prolonged and unnecessary therapy. The term biomarker is used in various ways, and here we use it to refer to 3 general types: 1) circulating blood macromolecules, 2) brain imaging, and 3) continuous invasive monitors. Despite its promise, biomarkers have several limitations and should be interpreted in the context of the overall clinical assessment.

Translating biomarkers research to clinical care: applications and issues for rehabilomics

Traumatic brain injury is a leading cause of morbidity and mortality in adults and children in the United States. Despite steady improvement in our understanding of the pathophysiology of acquired brain injuries, there has been remarkably little improvement in brain injury therapies and/or pharmacologic treatments over the past decade. One of the reasons may be the inability to properly stratify subjects for clinical trials and/or to have real-time assessment of the effectiveness of a given intervention. It has been recognized for several decades that serum biomarkers may allow for more objective subject stratification as well as act as surrogate markers of treatment efficacy. Despite numerous studies, however, biomarkers are not currently part of clinical practice in either acquired brain injury or other neurologic or musculoskeletal disorders. The goals of this review article, therefore, are to use traumatic brain injury as a example to discuss the use of biomarkers in clinical and randomized controlled trials; to briefly discuss the field of neuroproteomics and its interface with neurologic interventions; and to provide an overview of the collaborative pathway between academia and industry, which needs to be an integral part of the translation of biomarkers from the bench to the bedside in any clinical population. Introduction of the concept of rehabilomics and implications of biomarker use for the physical medicine and rehabilitation physician also are discussed.

Serum S100B in pregnancy complicated by preeclampsia: A case-control study

BACKGROUND

Serum S100B is a protein produced and released primarily by astrocytes of the Central Nervous System (CNS). Elevated levels of serum S100B are associated with several types of pathological conditions of the brain, including the eclampsia in pregnant women. The aim of this study was to compare serum S100B concentrations in pregnant women with severe and mild preeclampsia (PE) with S100B serum levels in normotensive pregnant women.

MATERIAL AND METHODS

Serum S100B protein was measured in normotensive pregnant women (n=15) and in women with mild PE (n=12) or severe PE (n=34). The serum S100B level (μg/L) was determined by an luminometric assay.

RESULTS

Sixty-one expectant mothers were studied, aged 26.6±8.7 (mean±SD) years and with a gestational age of 33.3±4.2 weeks. The severe PE group demonstrated higher S100B levels (0.20±0.19), as compared with mild PE (0.07±0.05) or normotensive groups (0.04±0.05).

CONCLUSION

Elevated serum S100B levels in pregnant women with severe PE suggest that some kind of neural damage and subsequent astrocytic release of S100B is not dependent on the progression from severe preeclampsia to eclampsia.

Serum ceruloplasmin and copper are early biomarkers for traumatic brain injury-associated elevated intracranial pressure

High intracranial pressure (ICP) is a prominent secondary pathology after traumatic brain injury (TBI) and is a major contributor to morbidity and mortality. Currently, there are no clinically proven methods for predicting which TBI patients will develop high ICP. In the present study, we examined whether the serum levels of the copper-binding protein ceruloplasmin are differentially altered in patients with elevated ICP (> or =25 mmHg) vs. those whose ICP remained below 20 mmHg throughout the study period. Consistent with its role as an acute-phase reactant, we found that ceruloplasmin levels were significantly increased by 3 days post-TBI compared with healthy volunteers. However, prior to this delayed increase, ceruloplasmin levels during the first 24 hr following injury were found to be significantly reduced in patients who subsequently developed high ICP. This decrease was found to have prognostic accuracy in delineating TBI patients based on their ICP status (cutoff of 140 microg/ml; sensitivity: 87%, specificity: 73%), Likewise, low total serum copper (below 1.32 microg/ml) was also found to be predictive of high ICP (sensitivity 86%, specificity 73%). These results suggest that initial serum ceruloplasmin/copper levels may have diagnostic value in predicting patients at risk for developing high intracranial pressure.

Identification and preliminary characterization of ubiquitin C terminal hydrolase 1 (UCHL1) as a biomarker of neuronal loss in aneurysmal subarachnoid hemorrhage

By using two different approaches, ubiquitin C-terminal hydrolase 1 (UCHL1) was identified as a potential cerebrospinal fluid (CSF) biomarker of neuronal loss in aneurysmal subarachnoid hemorrhage (ASAH) and presumably other CNS damage and disease states. Appropriate antibodies and a sensitive ELISA were generated, and the release of UCHL1 into CSF was compared with that of pNF-H and S100beta in a cohort of 30 ASAH patients. Both UCHL1 and pNF-H showed persistent release into CSF in almost all patients in the second week postaneurysmal rupture (AR), and S100beta levels rapidly declined to baseline levels in 23 of 30 patients. Seven of thirty patients showed persistently elevated S100beta levels over the first 5 days post-AR and also had relatively higher levels of pNF-H and UCHL1 higher compared with the rest. These patients proved to have very poor outcomes, with 6 of 7 expiring. Patients who did reduce S100beta levels tended to have a better outcome if pNF-H and UCHL1 levels were also lower, and elevated UCHL1 levels in the second week post-AR were particularly predictive of poor outcome. Acute coordinated releases of large amounts of UCHL1, pNF-H, and S100beta in 16 of 30 patients were observed, suggesting sudden loss of brain tissues associated with secondary events. We conclude that measurement of the CSF levels of these proteins reveals details of ASAH progression and recovery and predicts patient outcome.

Tau proteins in the cerebrospinal fluid of patients with subacute sclerosing panencephalitis

Neurodegenerative diseases characterized by cytoskeletal deformation and neurofibrillary tangles are associated with altered levels of tau and related proteins in cerebrospinal fluid (CSF). Neuronal or glial fibrillary tangles have been shown in 20% of subacute sclerosing panencephalitis (SSPE) patients. We therefore investigated CSF samples from 60 newly diagnosed SSPE and 31 neurological control patients for total tau (t-tau), phosphorylated tau (p-tau), and S100-B levels by ELISA. There was no difference between patient and control groups in t-tau and S100-B levels. p-Tau was lower in the SSPE group (p=0.009). Past history of measles infection, measles immunization status, latent period between measles and onset of SSPE, duration of symptoms, frequency of myoclonia, neurological deficit index, stage and progression rate of the disease, CSF glucose levels and cell counts, CSF and serum measles IgG titer, distribution of lesions on brain magnetic resonance imaging were not related to t-tau, p-tau and S100-B levels. Mental status and age were negatively correlated with t-tau, and male gender and EEG abnormalities were associated with higher t-tau levels. The levels of tau proteins in our patients suggest there is no, or only scarce and immature, neurofibrillary tangle formation in SSPE. Autopsy studies showing neurofibrillary tangles might have examined older patients with longer disease and more parenchymal involvement.

Neuronal and glial cerebrospinal fluid protein biomarkers are elevated after West Nile virus infection

Neurotrophic West Nile virus (WNV) disease is a severe arbovirus infection in which neuronal loss is the likely anatomical substrate for the high morbidity and mortality. We investigated whether cerebrospinal fluid (CSF) protein biomarkers were elevated in vivo and related to disease severity in patients with WNV infection. This exploratory study included 114 patients (24 acute WNV, 77 noninflammatory controls, six peripheral neuropathies, seven aseptic meningoencephalitis). CSF levels of neuronal (neurofilaments, NfH-SMI35) and glial (glial fibrillary acidic protein, GFAP, S100B) biomarkers were measured by enzyme-linked immunosorbent assay (ELISA). Immunocytochemistry was performed in two fatal WNV cases. A significant proportion of patients with WNV had pathological CSF levels for NfH-SMI35 (58%, median concentration 1.01 ng/mL), GFAP (58%, 10 pg/mL), and S100B (90%, 1.29 ng/mL). The results were consistent with postmortem evidence for neuronal death and astrogliosis. Surprisingly, CSF protein biomarker levels were also found to be pathological in a considerable proportion of patients who presented with WNV fever only (100% for GFAP and S100B and 43% for NfH-SMI35). Elevated CSF protein biomarker levels are suggestive of neuronal death and glial pathology in human WNV infection. The results indicate the presence of neuroinvasive disease across the spectrum of WNV disease, including WNV fever.

Prospective evaluation of a predictive model of mortality in patients with isolated head injury

BACKGROUND

In a previous retrospective study, we developed a predictive model of survival in isolated head injuries based on easily available parameters such as age, mechanism of injury, Glasgow Coma Scale, and head Abbreviated Injury Scale (AIS). The purpose of the present study is to prospectively evaluate this predictive model.

METHODS

Isolated head injuries admitted to a Level I urban trauma center were prospectively accrued from May 1, 2006 through April 30, 2007. Age, mechanism of injury, Glasgow Coma Scale, head AIS, and survival status were recorded for each patient. Patients with extracranial AIS >3, head AIS = 6, or hypotension were excluded. These data were entered into our previously developed predictive model and the percentage of correct classification was used to measure how well the predictive model predicted outcome. Sensitivity, specificity, positive and negative predictive values, and their 95% confidence intervals were calculated and compared with values obtained from our original, retrospective study.

RESULTS

Seven hundred eighty-six patients met the criteria for inclusion in the study with an overall mortality of 5.8% (46 patients). When entered into our predictive model, the percentage of correct classification rate was 92% compared with the 94% rate seen in the original study, which is better than other available predictive tools based on combined scoring systems such as the Trauma and Injury Severity Score methodology.

CONCLUSION

When evaluated prospectively, our predictive model has similar accuracy in predicting survival of all patients with head trauma as our original retrospective study and performs better than other predictive models such as the Trauma and Injury Severity Score methodology. This study demonstrates that a simple table based on easily obtained admission patient characteristics can rapidly provide information about the probability of survival in patients with head injuries.

Effects of mode of delivery on maternal–neonatal plasma antioxidant status and on protein S100B serum concentrations

OBJECTIVE

To investigate the effect of the mode of labour and delivery on total antioxidant status (TAS) and on the protein S100B serum concentrations in mothers and their newborns.

MATERIAL AND METHODS

Sixty women with normal pregnancies were divided into three groups: Group A (n = 20) with normal labour and vaginal delivery (VG), group B (n = 18) with prolonged labour+VG and group C (n = 22) with scheduled caesarean section (CS). Blood was obtained at the beginning of the labour process and immediately after delivery (pre- and post-delivery) as well as from the umbilical cord (CB). TAS and creatine kinase (CK) were measured using commercial kits. Serum S100B levels were evaluated with the electrochemiluminescence immunoassay "ECLIA" on the ROCHE ELECSYS 2010 immunoassay analyser.

RESULTS

Post-delivery, TAS levels were significantly decreased in group A and especially in group B. S100B levels were increased in group B (0.0712+/-0.02 microg/L) as compared with those of group A (0.0567+/-0.03 microg/L, p<0.01) and group C (0.038+/-0.03 microg/L, p<0.01), the levels in group C remaining practically unaltered (pre- versus post-delivery). In the newborns, S100B levels were almost 2-fold higher in group B (0.67+/-0.18 microg/L) than those in group A (0.40+/-0.05 microg/L p<0.001) and group C (0.31+/-0.04 microg/L p<0.001). A negative correlation was found between TAS and S100B protein (r = -0.61, p<0.001), the latter positively correlated to CK (r = 0.48, p<0.01).

CONCLUSIONS

The increased S100B serum levels in the mothers of group B, post-delivery, may have been due to the long-lasting, oxidative and/or psychogenic stress. The observed remarkably high levels of S100B in the group B newborns may have been due to compressive conditions on the foetus brain during this mode of delivery.

Improving the recovery of S100B protein in cerebral microdialysis: implications for multimodal monitoring in neurocritical care

INTRODUCTION

Cerebral microdialysis is an established research tool that is used by an increasing number of neurocritical care units as a component of bedside multimodality monitoring. Body fluid biomarkers are an emerging tool for the assessment of brain injury. The correct interpretation of body fluid biomarker levels depends on the degree of recovery, i.e. relative recovery and the accuracy of the analytical technique.

METHODS

In vitro recovery experiments were performed on 100mL volumes of cerebrospinal fluid and solutions of S100B, glucose, lactate and pyruvate comparing relative recoveries using commercially available 20 kDa (CMA70) and 100 kDa (CMA71) microdialysis catheters. We also compared the CMA 600 microdialysis analyzer with a YSI 2003 STAT Plus analyzer for glucose and lactate to determine its reliability.

RESULTS

Significantly, we demonstrate the improved recovery of the protein S100B using a larger molecular weight (MW) cut-off catheter (20 kDa range: 0.1-9%; 100 kDa range: 1.7-18.3%) while maintaining comparable performance for the conventional markers glucose, lactate and pyruvate. Additionally we found that the CMA 600 analyzer may be prone to overestimation of lactate readings at higher concentration with implications for clinical decision-making.

CONCLUSION

Our data demonstrates that the 100 kDa MW cut-off catheter allows for the improved recovery of macromolecules in cerebral microdialysis research while maintaining the value of existing MD data for routine clinical use.

Diagnostic accuracy of S100B urinary testing at birth in full-term asphyxiated newborns to predict neonatal death

BACKGROUND

Neonatal death in full-term infants who suffer from perinatal asphyxia (PA) is a major subject of investigation, since few tools exist to predict patients at risk of ominous outcome. We studied the possibility that urine S100B measurement may identify which PA-affected infants are at risk of early postnatal death.

METHODOLOGY/PRINCIPAL FINDINGS

In a cross-sectional study between January 1, 2001 and December 1, 2006 we measured S100B protein in urine collected from term infants (n = 132), 60 of whom suffered PA. According to their outcome at 7 days, infants with PA were subsequently classified either as asphyxiated infants complicated by hypoxic ischemic encephalopathy with no ominous outcome (HIE Group; n = 48), or as newborns who died within the first post-natal week (Ominous Outcome Group; n = 12). Routine laboratory variables, cerebral ultrasound, neurological patterns and urine concentrations of S100B protein were determined at first urination and after 24, 48 and 96 hours. The severity of illness in the first 24 hours after birth was measured using the Score for Neonatal Acute Physiology-Perinatal Extension (SNAP-PE). Urine S100B levels were higher from the first urination in the ominous outcome group than in healthy or HIE Groups (p<0.001 for all), and progressively increased. Multiple logistic regression analysis showed a significant correlation between S100B concentrations and the occurrence of neonatal death. At a cut-off >1.0 microg/L S100B had a sensitivity/specificity of 100% for predicting neonatal death.

CONCLUSIONS/SIGNIFICANCE

Increased S100B protein urine levels in term newborns suffering PA seem to suggest a higher risk of neonatal death for these infants.

Serum biomarker concentrations and outcome after pediatric traumatic brain injury

Predicting outcome after pediatric traumatic brain injury (TBI) is important for providing information to families and prescribing rehabilitation services. The study objective was to assess whether biomarkers concentrations obtained at the time of injury are associated with outcome. Serial serum concentrations of neuron-specific enolase (NSE), S100B and myelin basic protein (MBP) were measured in 152 children with acute TBI. Outcome was assessed with the Glasgow Outcome Scale (GOS) score and/or GOS-Extended Pediatric (GOS-E Peds). Spearman's rank correlation and binary logistic regression assessed the relationship between biomarker concentrations and outcome. For all biomarkers and time points, higher biomarker concentrations were associated with worse outcome. Initial and peak NSE concentrations and initial MBP concentrations were more strongly correlated with outcome in children < or =4 years compared with those >4 years of age. Using binary logistic regression to evaluate the simultaneous affect of all biomarkers on outcome, there was significant overall model fit predicting a dichotomous GOS from biomarker concentrations with a 77% correct classification rate and a negative and positive predictive value of 97% and 75%, respectively. We conclude that NSE, S100B, and MBP concentrations obtained at the time of TBI may be useful in predicting outcome. Future studies should focus on assessing the differential benefit of biomarkers compared with clinical variables and in assessing a continuous rather than categorical outcome variable.

Plasma von Willebrand factor levels correlate with clinical outcome of severe traumatic brain injury

Biochemical markers of cellular stress/injury have been proposed to indicate outcome after head injury. The aim of the present study was to determine whether plasma von Willebrand factor (VWF) levels correlate with primary outcome and with clinical variables in severe traumatic brain injury (TBI). Forty-four male patients, victims of severe TBI, were analyzed. Clinical outcome variables of severe TBI comprised survival and neurological assessment using the Glasgow Outcome Scale (GOS) at intensive care unit (ICU) discharge. Computerized tomography (CT) scans were analyzed according to Marshall CT classification. Three consecutive venous blood samples were taken: first sample (11.4 +/- 5.2 h after trauma, mean +/- SD), and 24 h and 7 days later. The result of mean plasma VWF concentration was significantly higher in the TBI group (273 U/dL) than in the control group (107 U/dL; p < 0.001). Severe TBI was associated with a 50% mortality rate. Nonsurvivors presented significantly higher APACHE II scores than survivors (nonsurvivors mean, 18.8; survivors mean, 12.7; p < 0.001), and also presented higher scores in Marshall CT classification (nonsurvivors mean, 4.6; survivors mean, 2.7; p < 0.05). There was a significant positive correlation between plasma levels at second plasma sampling and scores in Marshall CT classification (p < 0.05). The sensitivity of plasma VWF concentration in predicting mortality according to the cut-off of 234 U/dL was 64%, with a specificity of 68%. Therefore, VWF increases following severe TBI may be a marker of unfavorable outcome.

Reliability of S100B in predicting severity of central nervous system injury

S100B is a protein biomarker that reflects CNS injury. It can be measured in the CSF or serum with readily available immunoassay kits. The excellent sensitivity of S100B has enabled it to confirm the existence of subtle brain injury in patients with mild head trauma, strokes, and after successful resuscitation from cardiopulmonary arrest. The extent of S100B elevation has been found to be useful in predicting clinical outcome after brain injury. Elevations of S100B above certain threshold levels might be able to reliably predict brain death or mortality. A normal S100B level reliably predicts the absence of significant CNS injury. The specificity of S100B levels as a reflection of CNS injury is compromised by the findings that extra-cranial injuries can lead to elevations in the absence of brain injury. This potential problem can most likely be avoided by measuring serial S100B levels along with other biomarkers and carefully noting peripheral injuries. Serum markers GFAP and NSE are both more specific for CNS injury and have little to no extra-cranial sources. Sustained elevations of S100B over 24 h along with elevations of GFAP and NSE can more reliably predict the extent of brain injury and clinical outcomes. In the future, S100B measurements might reliably predict secondary brain injury and enable physicians to initiate therapeutic interventions in a timelier manner. S100B levels have been shown to rise hours to days before changes in ICP, neurological examinations, and neuroimaging tests. S100B levels may also be used to monitor the efficacy of treatments.

S100B in neuropathologic states: the CRP of the brain?

In recent years there has been a proliferation of interest in the brain-specific protein S100B, its many physiologic roles, and its behaviour in various neuropathologic conditions. Since the mid-1960s, its wide variety of intracellular and extracellular activities has been elucidated, and it has also been implicated in an increasing number of central nervous system (CNS) disorders. S100B is part of a superfamily of proteins, some of which (including S100B) have been implicated as calcium-dependent regulatory proteins that modulate the activity of effector proteins or cells. S100B is primarily an astrocytic protein. Within cells, it may have a role in signal transduction, and it is involved in calcium homeostasis. Information about the functional implication of S100B secretion by astrocytes into the extracellular space is scant but there is substantial evidence that secreted glial S100B exerts trophic or toxic effects depending on its concentration. This review summarises the historic development and current knowledge of S100B, including recent interesting findings relating S100B to a diversity of CNS pathologies such as traumatic brain injury, Alzheimer's disease, Down's syndrome, schizophrenia, and Tourette's syndrome. These broad implications have led some workers to describe S100B as 'the CRP (C-reactive protein) of the brain.' This review also examines S100B's potential role as a neurologic screening tool, or biomarker of CNS injury, analogous to the role of CRP as a marker of systemic inflammation.

Role of Plasma DNA as a Predictive Marker of Fatal Outcome following Severe Head Injury in Males

The prediction of outcome is one of the major problems associated with traumatic brain injury. Recently, investigations have been performed on the potential use of circulating cell-free DNA in plasma for clinical diagnosis and prognosis of a variety of conditions. In this study, we investigated DNA plasma concentrations after severe traumatic brain injury (TBI) and its correlation with primary outcome. We studied 41 male victims of TBI, with isolated severe TBI or severe TBI with associated exracranial injuries. Control samples were obtained from 13 healthy male volunteers. Plasma DNA was measured by a real-time PCR assay for the beta-globin gene. The mean time for first sampling (study entry) was 11.7 +/- 5.2 h after injury; subsequent DNA determinations were performed 24 h after study entry. Mean plasma DNA concentrations were significantly increased in TBI patients (366,485 and 131,708 kilogenomes-equivalents/L, at study entry and 24 h later, respectively) compared with the control group (3031 kilogenomes-equivalents/L). Additionally, a significant correlation between higher plasma DNA concentrations, determined 24 h after study entry, and fatal outcome was observed. However, at second sampling, there was no significant correlation between plasma DNA concentrations and the presence of associated extracranial injuries. High plasma DNA concentrations at second sampling time predicted fatal outcome with a sensitivity of 67% and specificity of 76%, considering a cut-off value of 77,883 kilogenomes-equivalents/L. Thus, this study showed that severe TBI is associated with elevated DNA plasma levels and suggests that persistent DNA elevations correlate with mortality.

Role of serum S100B as a predictive marker of fatal outcome following isolated severe head injury or multitrauma in males

BACKGROUND

Severe traumatic brain injury (TBI) is associated with a 30%-70% mortality rate. S100B has been proposed as a biomarker for indicating outcome after TBI. Nevertheless, controversy has arisen concerning the predictive value of S100B for severe TBI in the context of multitrauma. Therefore, our aim was to determine whether S100B serum levels correlate with primary outcome following isolated severe TBI or multitrauma in males.

METHODS

Twenty-three consecutive male patients (age 18-65 years), victims of severe TBI [Glasgow Coma Scale (GCS) 3-8] (10 isolated TBI and 13 multitrauma with TBI) and a control group consisting of eight healthy volunteers were enrolled in this prospective study. Clinical outcome variables of severe TBI comprised: survival, time to intensive care unit (ICU) discharge, and neurological assessment [Glasgow Outcome Scale (GOS) at ICU discharge]. Venous blood samples were taken at admission in the ICU (study entry), 24 h later, and 7 days later. Serum S100B concentration was measured by an immunoluminometric assay.

RESULTS

At study entry (mean time 10.9 h after injury), mean S100B concentrations were significantly increased in the patient with TBI (1.448 microg/L) compared with the control group (0.037 microg/L) and patients with fatal outcome had higher mean S100B (2.10 microg/L) concentrations when compared with survivors (0.85 microg/L). In fact, there was a significant correlation between higher initial S100B concentrations and fatal outcome (Spearman's =0.485, p=0.019). However, there was no correlation between higher S100B concentrations and the presence of multitrauma. The specificity of S100B in predicting mortality according to the cut-off of 0.79 microg/L was 73% at study entry.

CONCLUSIONS

Increased serum S100B levels constitute a valid predictor of unfavourable outcome in severe TBI, regardless of the presence of associated multitrauma.