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

Release of glial fibrillary acidic protein is related to the neurovascular status in acute ischemic stroke

This study aimed at an analysis of glial fibrillary acidic protein (GFAP) in acute ischemic stroke, its association with the neurovascular status and its potential value as monitoring parameter. In 53 consecutive patients, serial venous blood samples were taken on admission, 6, 12, 18, 24, 48, 72, 96, and 120 h after stroke onset. The neurovascular status was assessed by repetitive extracranial and transcranial duplex sonography. Neurologic deficits were quantified by the National Institutes of Health stroke scale, and functional outcome was assessed with the modified Rankin Scale. Mean GFAP values were elevated from admission on with highest levels 48 h after stroke onset. GFAP release was highly correlated with severity of neurologic deficits and infarct volume. In patients with persistent middle cerebral artery occlusion, GFAP increased significantly compared with patients with normal sonographic findings (P = 0.019) and recanalization after thrombolysis resulted in a significant reduced increase (P = 0.038). GFAP concentrations were associated with the functional outcome after 3 months. Release kinetics of GFAP are associated with patients clinical deficits and infarct volume, depend on the neurovascular status on admission and on early recanalization after thrombolysis, and may be used as an additional predictor of the early course and functional outcome.

A Critical Analysis of the Role of the Neurotrophic Protein S100B in Acute Brain Injury

We provide a critical analysis of the relevance of S100B in acute brain injury emphazising the beneficial effect of its biological properties. S100B is a calcium-binding protein, primarily produced by glial cells, and exerts auto- and paracrine functions. Numerous reports indicate, that S100B is released after brain insults and serum levels are positively correlated with the degree of injury and negatively correlated with outcome. However, new data suggest that the currently held view, that serum measurement of S100B is a valid "biomarker" of brain damage in traumatic brain injury (TBI), does not acknowlege the multifaceted release pattern and effect of the blood-brain barrier disruption upon S100B levels in serum. In fact, serum and brain S100B levels are poorly correlated, with serum levels dependent primarily on the integrity of the blood-brain barrier, and not the level of S100B in the brain. The time profile of S100B release following experimental TBI, both in vitro and in vivo, suggests a role of S100B in delayed reparative processes. Further, recent findings provide evidence, that S100B may decrease neuronal injury and/or contribute to repair following TBI. Hence, S100B, far from being a negative determinant of outcome, as suggested previously in the human TBI and ischemia literature, is of potential therapeutic value that could improve outcome in patients who sustain various forms of acute brain damage.

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.

Aspirin-induced blockade of NF-kappaB activity restrains up-regulation of glial fibrillary acidic protein in human astroglial cells

The marked induction of glial fibrillary acidic protein (GFAP) has been observed in astrocytes during neuropathological processes accompanying reactive gliosis; however, the precise molecular mechanism(s) underlying this GFAP induction remains poorly resolved. Therefore, in this study, we examined whether the change of nuclear factor-kappa B (NF-kappaB) activity can influence GFAP expression levels. Aspirin, widely used to prevent NF-kappaB activity, reduced the levels of GFAP mRNA and protein in human astroglial cells including human glioblastoma A172 cells and primary human brain astrocyte cells (HBAs). Furthermore, aspirin inhibited the effects of hypoxic injury on the up-regulation of GFAP expression in HBAs. We confirmed the repressive effect of aspirin on GFAP transcription by GFAP promoter-driven reporter assay and found that one NF-kappaB binding site conserved in the mouse and human GFAP gene promoters is critical for this effect. To further delineate whether NF-kappaB is directly involved in the regulation of GFAP gene expression, we transfected A172 cells with an expression vector encoding a super-repressor IkappaBalpha protein (IkappaBalpha-SR) to specifically inhibit NF-kappaB activity and found the marked reduction of GFAP protein levels in IkappaBalpha-SR-transfectant cells. Taken together, our results suggest that NF-kappaB may play pivotal roles in GFAP gene expression.

Measurement of S-100B for risk classification of victims sustaining minor head injury--first pilot study in Brazil

BACKGROUND

Release of the neuronal protein S-100B into the circulation has been suggested as a specific indication of neuronal damage. The hypothesis that S-100B is a useful and cost-effective screening tool for the management of minor head injuries was tested.

METHODS

Fifty consecutive patients sustaining isolated minor head injury were prospectively evaluated in the emergency room of a Brazilian hospital by routine cranial computed tomography scan. Venous blood samples (processed to serum) were assayed for S-100B using a newly developed immunoassay test kit. Twenty-one normal healthy individuals served as negative controls. Data are presented as median and 25 to 75 percentiles.

RESULTS

Patients reached the emergency room an average of 45 minutes (range: 30-62 minutes) after minor head injury. Six of 50 patients (12%) showed relevant posttraumatic lesions in the initial cranial computed tomography scan and were counted as positive. The median systemic concentration of S-100B in those patients was 0.75 microg/L (range: 0.66-6.5 microg/L), which was significantly different (U-test, P < .05) from the median concentration of 0.26 microg/L (range: 0.12-0.65 microg/L), of patients without posttraumatic lesions as counted by the cranial computed tomography. A sensitivity of 100%, a specificity of 20%, a positive predictive value of 15%, and a negative predictive value of 100% was calculated for the detection of patients suffering from intracranial lesions.

CONCLUSIONS

Protein S-100B had a very high sensitivity and negative predictive value and could have an important role in ruling out the need for cranial computed tomography scan after minor head injury. This appears to be of substantial clinical relevance, particularly in countries where trauma incidence is high and medical resources are limited, such as in Brazil.

Approach to the comatose patient

BACKGROUND

Coma is a medical emergency and may constitute a diagnostic and therapeutic challenge for the intensivist.

OBJECTIVE

To review currently available data on the etiology, diagnosis, and outcome of coma. To propose an evidence-based approach for the clinical management of the comatose patient.

DATA SOURCE

Search of Medline and Cochrane databases; manual review of bibliographies from selected articles and monographs.

DATA SYNTHESIS AND CONCLUSIONS

Coma and other states of impaired consciousness are signs of extensive dysfunction or injury involving the brainstem, diencephalon, or cerebral cortex and are associated with a substantial risk of death and disability. Management of impaired consciousness includes prompt stabilization of vital physiologic functions to prevent secondary neurologic injury, etiological diagnosis, and the institution of brain-directed therapeutic or preventive measures. Neurologic prognosis is determined by the underlying etiology and may be predicted by the combination of clinical signs and electrophysiological tests.