La protéine S100B : premier marqueur biologique pour le diagnostic du traumatisme crânien mineur ou modéré

S100B, Actor and Biomarker of Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) accounts for approximately 80% of all TBI cases and is a growing source of morbidity and mortality worldwide. To improve the management of children and adults with mTBI, a series of candidate biomarkers have been investigated in recent years. In this context, the measurement of blood biomarkers in the acute phase after a traumatic event helps reduce unnecessary CT scans and hospitalizations. In athletes, improved management of sports-related concussions is also sought to ensure athletes’ safety. S100B protein has emerged as the most widely studied and used biomarker for clinical decision making in patients with mTBI. In addition to its use as a diagnostic biomarker, S100B plays an active role in the molecular pathogenic processes accompanying acute brain injury. This review describes S100B protein as a diagnostic tool as well as a potential therapeutic target in patients with mTBI.

S100B protein as a screening tool for computed tomography findings after mild traumatic brain injury: Systematic review and meta-analysis

PRIMARY OBJECTIVE

To determine whether S100B protein in serum can predict intracranial lesions on computed tomography (CT) scan after mild traumatic brain injury (MTBI).

RESEARCH DESIGN

Systematic review and meta-analysis Methods and procedures: A literature search was conducted using Medline, Embase, Cochrane, Google Scholar, CINAHL, SUMSearch, Bandolier, Trip databases, bibliographies from identified articles and review article references. Eligible articles were defined as observational studies including patients with MTBI who underwent post-traumatic head CT scan and assessing the screening role of S100B protein.

MAIN OUTCOMES AND RESULTS

There was a significant positive association between S100B protein concentration and positive CT scan (22 studies, SMD = 1.92, 95% CI = 1.29-2.45, I² = 100%; p < 0.001). The pooled sensitivity and specificity values for a cut-point range = 0.16-0.20 µg L^-1 were 98.65 (95% CI = 95.53-101.77; I² = 0.0%) and 50.69 (95% CI = 40.69-60.69; I² = 76.3%), respectively. The threshold for serum S100B protein with 99.63 (95% CI = 96.00-103.25; I² = 0.0%) sensitivity and 46.94 (95% CI = 39.01-54.87; I² = 95.5%) specificity was > 0.20 µg L^-1.

CONCLUSIONS

After MTBI, serum S100B protein levels are significantly associated with the presence of intracranial lesions on CT scan. Measuring the protein could be useful in screening high risk MTBI patients and decreasing unnecessary CT examinations.

MicroRNAs with Specific Roles in Diabetes and Psychiatric Diseases

Diabetes mellitus is one of the most cited non communicable diseases and the most common metabolic disorder. Epigenetics represents the field of study of heritable changes in gene expression which are not directly related to DNA. Epigenetics is concerned, alongside histone modifications, short interfering RNAs etc., with microRNAs (miRNAs) as well. These are small noncoding RNAs, 21 to 23 nucleotides in length, which either inhibit translation or affect mRNA stability and degradation. At present, there are dozens of miRNAs which have been proven to be involved in the animal and human pathology of diabetes (type 1 or 2). This review focuses on the miRNAs which have been identified as playing a role in both psychiatric diseases and diabetes.

S100B and schizophrenia

The research for peripheral biological markers of schizophrenia, although abundant, has been unfruitful. In the last 2 decades, the S100B protein has made its own room in this area of research. S100B is a calcium-binding protein that has been proposed as a marker of astrocyte activation and brain dysfunction. Research results on S100B concentrations and schizophrenia clinical diagnosis are very consistent; patients with schizophrenia have higher S100B concentrations than healthy controls. The results regarding schizophrenia subtypes and clinical characteristics are not as conclusive. Age of patients, body mass index, illness duration and age at onset have been found to show no correlation, a positive correlation or a negative correlation with S100B levels. With respect to psychopathology, S100B data are inconclusive. Positive, negative and absence of correlation between S100B concentrations and positive and negative psychopathology have been reported. Methodological biases, such as day/night and seasonal variations, the use of anticoagulants to treat biological samples, the type of analytical technique to measure S100B and the different psychopathological scales to measure schizophrenia symptoms, are some of the factors that should be taken into account when researching into this area in order to reduce the variability of the reported results. The clinical implications of S100B changes in schizophrenia remain to be elucidated.

S100-B protein as a screening tool for the early assessment of minor head injury

STUDY OBJECTIVE

A computed tomography (CT) scan has high sensitivity in detecting intracranial injury in patients with minor head injury but is costly, exposes patients to high radiation doses, and reveals clinically relevant lesions in less than 10% of cases. We evaluate S100-B protein measurement as a screening tool in a large population of patients with minor head injury.

METHODS

We conducted a prospective observational study in the emergency department of a teaching hospital (Bordeaux, France). Patients with minor head injury (2,128) were consecutively included from December 2007 to February 2009. CT scans and plasma S100-B levels were compared for 1,560 patients. The main outcome was to evaluate the diagnostic value of the S100-B test, focusing on the negative predictive value and the negative likelihood ratio.

RESULTS

CT scan revealed intracranial lesions in 111 (7%) participants, and their median S100-B protein plasma level was 0.46 μg/L (interquartile range [IQR] 0.27 to 0.72) versus 0.22 μg/L (IQR 0.14 to 0.36) in the other 1,449 patients. With a cutoff of 0.12 μg/L, traumatic brain injuries on CT were identified with a sensitivity of 99.1% (95% confidence interval [CI] 95.0% to 100%), a specificity of 19.7% (95% CI 17.7% to 21.9%), a negative predictive value of 99.7% (95% CI 98.1% to 100%), a positive likelihood ratio of 1.24 (95% CI 1.20 to 1.28), and a negative likelihood ratio of 0.04 (95% CI 0.006 to 0.32).

CONCLUSION

Measurement of plasma S100-B on admission of patients with minor head injury is a promising screening tool that may be of help to support the clinician's decision not to perform CT imaging in certain cases of low-risk head injury.

The anti-inflammatory and neuroprotective effects of ghrelin in subarachnoid hemorrhage-induced oxidative brain damage in rats

To elucidate the putative neuroprotective effects of ghrelin in subarachnoid hemorrhage (SAH)-induced brain injury, Wistar albino rats (n = 54) were divided into sham-operated control, saline-treated SAH, and ghrelin-treated (10 microg/kg/d IP) SAH groups. The rats were injected with blood (0.3 mL) into the cisterna magna to induce SAH, and were sacrificed 48 h after the neurological examination scores were recorded. In plasma samples, neuron-specific enolase (NSE), S-100beta protein, TNF-alpha, and IL-1beta levels were evaluated, while forebrain tissue samples were taken for the measurement of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species levels, myeloperoxidase (MPO), Na(+)-K(+)-ATPase activity, and DNA fragmentation ratio. Brain tissue samples containing the basilar arteries were obtained for histological examination, while cerebrum and cerebellum were removed for the measurement of blood-brain barrier (BBB) permeability and brain water content. The neurological scores were impaired at 48 h after SAH induction, and SAH caused significant decreases in brain GSH content and Na(+)-K(+)-ATPase activity, and increases in chemiluminescence, MDA levels, and MPO activity. Compared with the control group, the protein levels of NSE, S-100beta, TNF-alpha, and IL-1beta in plasma were also increased, while ghrelin treatment prevented all SAH-induced alterations observed both biochemically and histopathologically. The results demonstrate that ghrelin alleviates SAH-induced oxidative brain damage, and exerts neuroprotection by maintaining a balance in oxidant-antioxidant status, by inhibiting proinflammatory mediators, and preventing the depletion of endogenous antioxidants evoked by SAH.

Early prognosis in traumatic brain injury: from prophecies to predictions

Traumatic brain injury (TBI) is a heterogeneous condition that encompasses a broad spectrum of disorders. Outcome can be highly variable, particularly in more severely injured patients. Despite the association of many variables with outcome, prognostic predictions are notoriously difficult to make. Multivariable analysis has identified age, clinical severity, CT abnormalities, systemic insults (hypoxia and hypotension), and laboratory variables as relevant factors to include in models to predict outcome in individual patients. Advances in statistical modelling and the availability of large datasets have facilitated the development of prognostic models that have greater performance and generalisability. Two prediction models are currently available, both of which have been developed on large datasets with state-of-the-art methods, and offer new opportunities. We see great potential for their use in clinical practice, research, and policy making, as well as for assessment of the quality of health-care delivery. Continued development, refinement, and validation is advocated, together with assessment of the clinical impact of prediction models, including treatment response.