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

S100B is not a reliable prognostic index in paediatric TBI

BACKGROUND

As far as paediatric traumatic brain injury is concerned, it is difficult to quantify the extent of the primary insult, to monitor secondary changes and to predict neurological outcomes by means of the currently used diagnostic tools: physical examination, Glasgow Coma Scale (GCS) score and computed tomography. For this reason, several papers focused on the use of biochemical markers (S100B, neuron-specific enolase) to detect and define the severity of brain damage and predict outcome after traumatic head injury or cardiac arrest.

OBJECTIVE

The aim of this paper is measuring the range of S100B serum concentrations in children affected by traumatic brain injury and describing the possible roles of this protein in the reaction to trauma.

METHODS

Fifteen children aged 1-15 years were included in the study. Traumatic brain injury severity was defined by paediatric GCS score as mild (9 patients), moderate (2 patients) or severe (4 patients). Blood samples for S100B serum measurement were taken at emergency department admission and after 48 h.

RESULTS

The serum S100B concentration was higher in the group of severe trauma patients, who scored the lowest on the GCS at admission, and among them, the highest values were reported by the children with concomitant peripheral lesions.

CONCLUSIONS

The role of S100B in paediatric traumatic brain injury has not been clarified yet, and the interpretation of its increase when the head trauma is associated with other injuries needs the understanding of the physiopathological mechanisms that rule its release in the systemic circulation. The levels of S100B in serum after a brain injury could be related to the mechanical discharge from a destroyed blood-brain barrier, or they could be due to the active expression by the brain, as a part of its involvement in the systemic inflammatory reaction. Early increase of this protein is not a reliable prognostic index of neurological outcome after pediatric traumatic brain injury, since even very elevated values are compatible with a complete neurological recovery.

Serum S-100B protein monitoring in patients with severe traumatic brain injury

OBJECTIVE

S-100B protein is a promising marker of injury severity and outcome after head injury. We examined the relationship between serum S-100B concentrations and injury severity, clinical course, survival, and treatment efficacy after severe traumatic brain injury (TBI).

DESIGN AND SETTING

Prospective observational study in a neurosurgical intensive care unit.

PATIENTS AND PARTICIPANTS

102 adult patients with severe TBI, admitted between June 2001 and November 2003 (30 months).

INTERVENTIONS

Serum S-100B levels were measured by immunoluminometric technique on admission and every 24 h thereafter for a maximum of 7 days.

MEASUREMENTS AND RESULTS

Initial S-100B levels were significantly related to pupillary status, computed tomography severity 1, and 1-month survival. Cox's proportional hazard regression analysis showed that initial S-100B was an independent predictor of 1-month survival, in the presence of dilated pupils, and with increased age. Subjects with initial levels above 1 microg/l had a nearly threefold increased probability of death within 1 month. Serum S-100B alteration indicated neurological improvement or deterioration. Finally, surgical treatment reduced S-100B levels.

CONCLUSIONS

Serum S-100B protein reflects injury severity and improves prediction of outcome after severe TBI. S-100B may also have a role in assessing the efficacy of treatment after severe TBI.

Early identification of secondary brain damage in subarachnoid hemorrhage: a role for glial fibrillary acidic protein

Secondary ischaemic deficit adversely affects outcome in patients with subarachnoid hemorrhage (SAH). Astrocytes are vulnerable to ischemia, releasing glial fibrillary acidic protein (GFAP) when challenged. In this study, we followed nine patients with SAH who underwent extra-ventricular drainage for the management of secondary hydrocephalus. Cerebrospinal fluid (CSF) was collected daily for up to 14 days. CSF GFAP was quantified using a standard ELISA. In the patients, we found that the CSF GFAP values were pathologically elevated in 83/89 (93%) of the CSF samples. The levels were highest on day 1 (median = 47.64 ng/mL) and decreased to 11.19 ng/mL on day 3, leveling out at approximately 1 ng/mL after 10 days. In non-survivors, a secondary rise of GFAP levels became significant during the high-risk period for vasospasm, with median levels of 21.76 ng/mL compared to 2.62 ng/mL in the survivors (p = 0.037) on day 6. This study suggests that CSF GFAP levels are of prognostic value in SAH. Additionally, the difference in the slope of GFAP levels between survivors (rapid wash-out) and non-survivors (secondary peaks) may allow difierentiation between primary brain injury from secondary brain damage due to delayed cerebral ischaemia.

S100B protein in conscious carbon monoxide-poisoned rats treated with normobaric or hyperbaric oxygen

OBJECTIVE

To evaluate S100B, an astroglial structural protein, during normobaric and hyperbaric oxygen therapy of conscious carbon monoxide (CO)-poisoned rats. So far, the usefulness of hyperbaric oxygen therapy in conscious CO-poisoned patients has been shown with neuropsychological testing. The S100B protein has been demonstrated as a possible biochemical marker and prognostic parameter in CO-poisoned rats.

DESIGN

Randomized, controlled interventional trial.

SETTING

University laboratory.

SUBJECTS

: Male Wistar rats weighing 254 +/- 14 g.

INTERVENTIONS

The rats were exposed to a mixture of 3,000 ppm CO in air for 60 mins. After CO exposure, the first group of eight conscious rats was exposed to ambient air for 30 mins, the second group of six conscious rats was exposed to 100% normobaric oxygen for 30 mins, and the third group of six conscious rats was exposed to 100% hyperbaric oxygen at 3 bars for 30 mins. Blood samples were taken from the jugular vein just before CO exposure and immediately after oxygen therapy. The level of consciousness was evaluated at the end of exposure, and the survival rate was monitored for 14 days. The S100B concentrations were measured with a commercial immunoluminometric assay.

MEASUREMENTS AND MAIN RESULTS

Analyses of differences in S100B levels between different kinds of therapy before and after treatment showed a global significant difference (p = .002). The post hoc test results showed that S100B levels after therapy of the first group treated with ambient air (0.16 +/- 0.07 microg/L) and the second group treated with normobaric oxygen (0.19 +/- 0.05 microg/L) were similar (p = .741), and both of them were significantly different, with much higher values of S100B levels after therapy, from the third group treated with hyperbaric oxygen (0.06 +/- 0.03 microg/L; p = .018 and p = .002, respectively). All the rats survived.

CONCLUSIONS

S100B is elevated in conscious CO-poisoned rats left on ambient air or treated with normobaric oxygen, but not in conscious CO-poisoned rats treated with hyperbaric oxygen.

A multidisciplinary overview of cardiogenic shock

Cardiogenic shock complicating acute myocardial infarction (AMI) is reviewed from multidisciplinary viewpoints encompassing both basic and clinical aspects. Insights into the absolute obligate aerobic nature of the heart which possesses neither facultative capability nor functional collateral channels, together with O2 diffusion gradients, mitochondrial O2 sensing and anaerobic ATP deficiencies, are described in some detail. Myocardial adaptive responses against energy crisis, termed the Pasteur Effect, and hypoxia inducible factor (HIF)-1 alpha are implicated for cardiomyocyte viability. Oncosis and/or lysosomal autophagy cause such overwhelming numbers (several billions) of cardiomyocyte death, virtually simultaneously following coronary thrombotic occlusion. Apoptosis is briefly described and cardiogenic shock is discussed in terms of the diagnostic criteria by MIRU, unique hemodynamic manifestations, infarct sizes and border zone extension, and potentially jeopardized myocardium in the remote areas. Reperfusion injury, i.e., reactive oxygen species (ROS), is noted as a double-edged sword. The importance of early revascularization by means of PCI, CABG, and IABP support is emphasized according to current guidelines. For innovative promise in the future, de novo development of collateral channels by growth factors and trials of stem cell implantation aimed at myocardial regeneration are introduced.

The Use of Serum Biomarkers to Predict Outcome After Traumatic Brain Injury in Adults and Children

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in adults and children. Predicting outcome after TBI is difficult, but it is important for acute management, counseling of family members, and provision of rehabilitation services. Serum biomarkers may be useful alone or in combination with clinical variables to predict outcome after TBI. This article reviews the potential uses of serum biomarkers for the clinician, current literature related to the use of serum biomarkers for outcome prediction after adult and pediatric TBI, limitations of the literature, and future direction for this field.

Axonal damage and outcome in subarachnoid haemorrhage

BACKGROUND

On the basis of preliminary evidence from patients with subarachnoid haemorrhage (SAH), axonal degeneration is thought to be an underestimated pathological feature.

METHODS

A longitudinal study in 17 patients with aneurysmal SAH. Ventricular CSF was collected daily for up to 14 days. The neurofilament heavy chain(SMI35) (NfH(SMI35), a biomarker for axonal damage) was quantified using a standard ELISA (upper limit of normal 0.73 ng/ml). The primary outcome measure was the Glasgow Outcome Score (GOS) at 3 months.

RESULTS

Of 148 samples from patients with SAH, pathologically high NfH levels in the CSF were found in 78 (52.7%) samples, compared with 20 (5%) of 416 samples from the reference population (p<0.0001). A pathological increase in NfH was observed in all patients with a bad outcome (GOS 1-3) compared with 8% of those with a good outcome (GOS 4-5, p<0.0001). This increase typically became significant 7 days after the haemorrhage (p<0.01). The result was confirmed by analysing the individual mean NfH concentrations in the CSF (3.45 v 0.37 ng/ml, p<0.01), and was reinforced by the inverse correlation of NfH in the CSF with the GOS (r = -0.65, p<0.01). Severity of injury was found to be correlated to NfH(SMI35) levels in the CSF (World Federation of Neurological Surgeons, r = 0.63, p<0.01 and Glasgow Coma Score, r = -0.61, p<0.01).

CONCLUSION

Patients with SAH thus have secondary axonal degeneration, which may adversely affect their outcome.

S100B protein in urine of preterm newborns with ominous outcome

Prematurity is an important cause of perinatal death, and no reliable biochemical/biophysical markers exist to identify newborns with an increased mortality risk. We aimed to use S100B concentrations in urine as an early indicator of risk of neonatal death. We did a cross-sectional study using urine obtained from 165 preterm newborns, of whom 11 suffered neonatal death within the first week, 121 displayed no overt neurologic syndrome, and 33 suffered neonatal hypoxia and intraventricular hemorrhage (IVH) but not ominous outcome. Urine S100B concentrations were determined at four time-points and corrected for gestational age by conversion to multiples of median (MoM) of healthy controls of the same gestational age. Ultrasound imaging was assessed within the first 72 h from birth. In infants that died within the first week, S100B levels in urine were already higher than controls at first urination and increased progressively between the 24 and 96-h time-points. Multiple logistic regression analysis showed a significant correlation between urine S100B protein concentrations and the occurrence of neonatal death. An S100B concentration cut-off of 12.93 MoM at first urination had a sensitivity of 100% and a specificity of 97.8% for predicting an ominous outcome. The positive predictive value was 78.6%, the negative predictive value was 100%. Measurement of urine S100B protein levels in preterm newborns could be useful to identify newborns at higher risk of neonatal death.

Intestinal Ischemia-Reperfusion Injury Does Not Lead to Acute Central Nervous System Damage

BACKGROUND

The detrimental effects of intestinal ischemia reperfusion (IIR) injury on secondary organs including the liver, lungs, heart, and kidney have been widely investigated in animal models. However, the effect of IIR on the central nervous system (CNS) is largely unknown. We investigated the effect of IIR on the CNS as it may be of clinical relevance to patients at high risk of neurological injury.

MATERIALS AND METHODS

Adult male rats underwent IIR (60 min superior mesenteric artery occlusion followed by 120 min reperfusion, n = 7) or sham operation (n = 6) under anesthesia. Following the procedure, the cerebral hemispheres were removed for histological assessment and measurement of N-acetyl-aspartate (NAA), a marker of neuronal damage, by HPLC. Blood was taken for determination of plasma S100B concentration, a measure of glial cell damage by ELISA. Data are median (range).

RESULTS

Cerebral tissue from all animals from both groups was macroscopically and microscopically normal with no evidence of inflammation. NAA in brain homogenate was similar in the IIR group (0.2 [0.1-0.32] nmol/mg protein) and sham-operated group (0.19 [0.12-0.34], P = 0.83). Plasma S100B levels were higher in the IIR group compared to sham-operated animals but this difference was not statistically significant (1.13 [0.24-7.26] versus 0.55 [0.23-2.84] mug/l, P = 0.18).

CONCLUSIONS

In this model, IIR injury did not produce histological CNS changes nor biochemical changes suggestive of neuronal damage. Further work is required to elucidate any functional effect of IIR injury on the CNS.

Serum Hsp70 as an Early Predictor of Fatal Outcome after Severe Traumatic Brain Injury in Males

Severe traumatic brain injury (TBI) is associated with a 35-70% mortality rate. Biochemical markers of cellular stress/injury have been proposed to indicate outcome after head injury. Therefore, our aim was to determine whether Hsp70 could be detected in the serum of patients after severe TBI and whether serum levels of Hsp70 correlate with primary outcome in severe TBI. Twenty consecutive male patients, victims of severe TBI (GCS 3-8), were enrolled in this prospective study. Clinical outcome variables of severe TBI comprised: survival, time for ICU discharge, and neurological assessment using the Glasgow Outcome Scale (GOS) at the ICU discharge. Venous blood samples were taken at admission in the ICU (study entry), 24 h later, and 7 days later. A control group consisting of eight healthy male volunteers was also included. Serum Hsp70 levels were measured by an enzyme-linked immunosorbent assay. Mean serum Hsp70 concentrations were significantly increased in the TBI (97.6, 48.1, and 39.2 ng/mL, at study entry, 24 h later, and 7 days later, respectively) compared with the control group (12.2 ng/mL). Severe TBI was associated with a 50% mortality rate. On study entry (mean time 10.8 h after injury), a higher proportion of patients with fatal outcome had elevated serum Hsp70 (mean 143.5 ng/mL) concentrations when compared with survivors (mean 51.6 ng/mL). There was a significant correlation between higher initial serum Hsp70 concentrations and fatal outcome. The sensitivity of serum Hsp70 predicting mortality according to the cutoff of 62 ng/mL is 70% within 20 h after injury. Increased serum Hsp70 levels may constitute an early predictor of unfavorable outcome in severe TBI in males.

Axonal pathology in subarachnoid and intracerebral hemorrhage

Electrically active axons degenerate in the presence of nitric oxide (NO) in vitro. High CSF NO concentrations have been observed in patients with hemorrhagic brain injury such as subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH). This study investigated the evidence for axonal injury in SAH and ICH and related this to CSF NO levels. In this study, neurofilament phosphoforms (NfH(SMI34), NfH(SMI35), NfH(SMI38), NfH(SMI310)), surrogate markers for axonal injury, and NO metabolites (nitrate, nitrite = NOx) were measured by ELISA in cerebrospinal fluid (CSF) from patients with SAH and ICH and from a group of controls. Injury severity was classified using the Glasgow Coma Scale, and survival was used as the outcome measure. Compared to the control group, a higher proportion of patients with SAH and ICH had elevated NfH(SMI34) levels from day 0 to day 6 (p < 0.001), elevated NfH(SMI35) levels from day 1 to 6 (p < 0.001), and elevated NfH(SMI310) levels at day 0, 1, 4, and 6 (p < 0.001). The NOx levels were higher in the SAH and ICH patients than in the controls (p < 0.05) and distinguished the non-survivors from the survivors (p < 0.05). No direct correlation was found for NOx with any of the NfH phosphoforms. This study provides evidence for primary and secondary axonal injury in patients with SAH and ICH, with non-survivors also having higher NOx levels. CSF NfH phosphoforms might emerge as a putative surrogate marker for monitoring the development for secondary axonal degeneration in neurocritical care and guiding targeted neuroprotective strategies.

GFAP versus S100B in serum after traumatic brain injury: relationship to brain damage and outcome

Research indicates that glial fibrillary acidic protein (GFAP), part of the astroglial skeleton, could be a marker of traumatic brain injury (TBI). S100B, an astroglial protein, is an acknowledged marker of TBI. Our goal was to analyze the relationship of GFAP/S100B to brain damage and outcome, and to compare the accuracy of GFAP/S100B for prediction of mortality after TBI. Our prospective study included 92 patients admitted <12 h after TBI (median injury severity score 25, median Glasgow Coma Scale 6). TBI was verfied by computerized tomography. GFAP/S100B were measured immunoluminometrically at admission and daily in the intensive care unit (average 10 days, range 1-21 days). We compared GFAP/S100B in non-survivors versus survivors, accuracy for mortality prediction according to receiver operated characteristic curve analysis, correlation between GFAP and S100B, relationship of GFAP/S100B to computerized tomography, cerebral perfusion pressure (CPP), mean arterial pressure (MAP) and 3-month Glasgow Outcome Score (GOS). GFAP (p < 0.005) and S100B (p < 0.0005) were higher in non-survivors than survivors. Both GFAP and S100B were accurate for mortality prediction (area under curve 0.84 versus 0.78 at <12 h after TBI). GFAP and S100B release correlated better later than 36 h after TBI (r = 0.75) than earlier (r = 0.58). GFAP was lower in focal lesions of <25 mL than in shifts of >0.5 cm (p < 0.0005) and non-evacuated mass lesions of >25 mL (p < 0.005). S100B was lower in focal lesions of <25 mL than in non-evacuated mass lesions (p < 0.0005) and lower in swelling than in shifts of >0.5 cm (p < 0.005). GFAP and S100B were lower in ICP < 25 than ICP > or = 25 (p < 0.0005), in CPP > or = 60 than CPP < 60 (p < 0.0005), in MAP > 70 than MAP < or = 70 mm Hg, and in GOS 4-5 than GOS 1 (p < 0.0005). Both measurement of GFAP and S100B is a useful non-invasive means of identifying brain damage with some differences based on the pattern of TBI and accompanying multiple trauma and/or shock.

Search for melanoma markers in plasma and serum samples

Fourteen blood samples from patients with melanoma and eleven blood samples from healthy subjects were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The study was focussed on species of low molecular weight, in the range 800-5000 Da, present in plasma and sera. While for healthy subjects plasma samples lead to the production of a higher number of ionic species, for melanoma patients a high number of diagnostic ions, present with high frequency and with quite high relative abundance, are present in particular in serum samples and to a lesser extent also in plasma. Since plasma samples are obtained more easily in comparison to sera, it is possible to suggest that also plasma can be used for these studies.

Prognostic value of S100B protein in carbon monoxide-poisoned rats

OBJECTIVE

To assess the possible role of S100B, a structural protein of astroglial cells, as a biochemical marker in acute carbon monoxide-poisoned rats and to compare its prognostic value with consciousness level, which is one of the major parameters for treatment decision in acute carbon monoxide poisoning.

DESIGN

Nonrandomized, controlled interventional trial.

SETTING

University laboratory.

SUBJECTS

Male Wistar rats weighing 263 +/- 18 g.

INTERVENTIONS

The rats were exposed to a mixture of 3000 ppm carbon monoxide in air for 60 mins (group 1) and a mixture of 5000 ppm carbon monoxide in air for 30 mins (group 2). Blood samples were taken from the jugular vein just before and immediately after the carbon monoxide poisoning. The level of consciousness was evaluated at the end of the exposure, and the survival rate was monitored for 7 days. The S100B concentrations were measured with a commercial immunoluminometric assay.

MEASUREMENTS AND MAIN RESULTS

In the first group, the unconscious rats after carbon monoxide exposure had significantly higher S100B levels compared with the rats without loss of consciousness. In the second group, the unconscious rats that later died had significantly higher S100B levels compared with the unconscious rats that survived. The S100B levels of all conscious and unconscious surviving rats were not significantly different. The serum level of S100B below 0.44 microg/L predicted survival of carbon monoxide-poisoned rats, with a sensitivity of 100% and a specificity of 86%.

CONCLUSIONS

Acute carbon monoxide poisoning is associated with elevated S100B levels. S100B is a better predictor of final outcome than the consciousness level, so it could be used as a prognostic parameter for acute carbon monoxide poisoning in rats.

An ELISA for glial fibrillary acidic protein

Glial fibrillary acidic protein (GFAP) is the major intermediate filament protein of the astrocyte, and body fluid levels of GFAP are an important tool for estimating astrogliosis and astrocytic activation in vivo. This paper presents a new sandwich ELISA allowing quantification of GFAP(SMI26) from the cerebrospinal fluid (CSF). The sensitivity of the GFAP(SMI26) ELISA is 5 pg/ml with a recovery of 94% and a mean within- and between-batch precision of 6% and 10%, respectively. The upper reference value for CSF GFAP(SMI26) levels (9 pg/ml) was defined as the 95% cumulative frequency from 315 CSF samples. Based on this cut-off, a significantly higher proportion of patients with subarachnoid hemorrhage (100%), traumatic brain injury (100%), dementia (76%) and normal pressure hydrocephalus (85%) had pathologically elevated CSF GFAP(SMI26) levels compared to patients with peripheral nervous system disorders (0%). In a critical review of the literature, we compare the analytical and clinical sensitivity of previous GFAP ELISA methods with particular reference to patients with dementia.

S100B protein in carbon monoxide poisoning: a pilot study

Carbon monoxide (CO) poisoning is the most common form of lethal poisoning. The aim of this prospective clinical study was to assess the possible role of S100B, the structural protein in the astroglia, as a biochemical marker of brain injury in carbon monoxide poisoning. Serum S100B determination was performed in 38 consecutive patients poisoned by carbon monoxide who were admitted to the Emergency Department (ED) in Ljubljana. All three unconscious patients had elevated S100B levels. The patient with the highest S100B died. S100B was elevated in two of the six patients with initial transitory unconsciousness at the scene. All 29 patients without loss of consciousness had normal S100B levels. Carbon monoxide poisoning appears to be associated with elevated S100B levels.

Alterations in cerebrospinal fluid apolipoprotein E and amyloid beta-protein after traumatic brain injury

There is evidence that apolipoprotein E (apoE) and amyloid beta-protein (Abeta), which are implicated in the pathology of chronic neurodegenerative disorders, are involved in the response of the brain to acute injury; however, human in vivo evidence is sparse. We conducted a prospective observational study to determine the magnitude and time-course of alterations in cerebrospinal fluid (CSF) apoE and Abeta concentrations after traumatic brain injury (TBI), and the relationship of these changes to severity of injury and clinical outcome. Enzyme linked immunosorbant assay (ELISA) was used to assay apoE, Abeta(1-40) and Abeta(1-42) in serial CSF samples from 13 patients with TBI and 13 controls. CSF S100B and tau were assayed as surrogate markers of brain injury. There was a significant decrease in CSF apoE (p < 0.001) and Abeta (p< 0.001) after TBI contrasting the observed elevation in CSF S100B (p < 0.001) and tau (p < 0.001) concentration. There was significant correlation (r = 0.67, p = 0.01) between injury severity and the decrease in Abeta(1-40) concentration after TBI. In vivo, changes in apoE and Abeta concentration occur after TBI and may be important in the response of the human brain to injury.

Temporal alterations in cerebrospinal fluid amyloid beta-protein and apolipoprotein E after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The mechanism underlying the association between possession of the APOEepsilon4 allele and less favorable outcome after subarachnoid hemorrhage (SAH) remains to be determined. After SAH the level of apolipoprotein E (apoE) in the cerebrospinal fluid (CSF) is decreased, and lower levels are associated with more severe injury and less favorable outcome. This study examined serial CSF samples to determine the time course for the decrease in CSF apoE and the relationship between CSF apoE and amyloid beta-protein (Abeta), testing the hypothesis that apoE-Abeta interactions occur in vivo after SAH.

METHODS

Enzyme-linked immunosorbent assay was used to assay apoE, Abeta1-40, and Abeta1-42 in serial ventricular CSF samples from 19 patients with SAH and 13 controls. CSF S100B and tau were assayed as surrogate markers of brain injury.

RESULTS

There was a sustained decrease in CSF apoE (P<0.001) and Abeta (P<0.001) after SAH in contrast to the observed elevation in CSF S100B (P<0.001) and tau (P<0.001) concentration. There was significant correlation between CSF Abeta concentration and clinical outcome (r=0.65, P<0.01), and the decrease in CSF Abeta concentration correlated significantly with that of apoE (r=0.85, P<0.0001).

CONCLUSIONS

After SAH both apoE and Abeta levels decrease in the CSF, supporting the concept that interactions between these proteins occur in vivo. The possibility that apoE and Abeta influence outcome after SAH warrants further investigation.