Increase in Serum S100B Protein Level After a Swimming Race

S100B is expressed in, and released from, OLN-93 oligodendrocytes: Influence of serum and glucose deprivation

S100B (member of a family of proteins that are 100% soluble in ammonium sulfate at neutral pH) has been widely used as astrocyte marker in animal models and in human brain diseases. Recent studies revealed S100B-immunopositivity in oligodendrocytes and O2A oligodendroglial progenitor cells. It is unknown, however, if oligodendrocytes produce S100B themselves, or if the S100B-immunolabeling is caused by binding or absorption of the protein. To address this question, S100B expression and protein release were analyzed in a highly pure oligodendrocytic OLN-93 cell line (from rat), in the astrocytic C6 cell line (from rat) and primary astrocytes. S100B was gene expressed in all cultures, as revealed by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. OLN-93 cells and glial fibrillary acidic protein (GFAP)-negative astrocytes expressed the multiligand receptor for advanced glycation end products (RAGE). S100B protein levels were determined in supernatants and cell homogenates by immunoluminometry under normal conditions and after serum and glucose deprivation (SGD). SGD led to a several-fold increased release of S100B (after 6 and 24 h), which was particularly pronounced in primary astrocytes. Increased S100B in cell homogenates was most notable in OLN-93 cells under SGD, indicating activated S100B synthesis. These cells also showed the highest percentage of dead cells, as determined by propidium iodide-positivity, after SGD. Incubation with 0.5, 2 and 5 microg/l exogenous S100B was not toxic to OLN-93 cells. In conclusion, OLN-93 cells produce more S100B under SGD than astrocytes and are more susceptible to cell death upon SGD, which provokes leakage of S100B. Our data indicate active S100B secretion from astrocytes under SGD since highly elevated levels of S100B were detected in the supernatant despite a low percentage of dead cells. The experimental results provide further evidence for a production/release of S100B in/from oligodendrocytes, e.g. in metabolic stress conditions like cerebral ischemia. Studies on S100B in bodily fluids should be carefully interpreted in order to avoid misleading hypotheses concerning the specific involvement of astrocytes, due to the various cellular sources of S100B.

S100B protein and its clinical effect on craniocerebral injury

OBJECTIVE

To explore the role of S100B protein in the early diagnosis, treatment, and prognosis judgement of craniocerebral injury.

METHODS

In this study, we reviewed the domestic and foreign research reports about the relationship between S100B protein and craniocerebral injury.

RESULTS

The concentration of S100B protein had a different increase based on the degree of injury in early stage after craniocerebral injury, and the increasing degree of S100B protein showed a positive correlation with the grading of pathogenetic condition and prognosis of craniocerebral injury.

CONCLUSIONS

S100B protein may be taken as a specific index of early diagnosis, grading of pathogenetic condition, and prognosis judgement after craniocerebral injury. To grasp and regulate the mechanism of neurotoxicity and to elucidate the therapeutic effect of S100B protein will be a research direction in clinical treatment of craniocerebral injury.

The effect of α-Tocopherol supplementation on training-induced elevation of S100B protein in sera of basketball players

OBJECTIVE

To investigate the effect of alpha-Tocopherol (alpha-T) supplementation on S100B elevated serum levels in basketball players' training.

DESIGN

Blood was obtained from 10 basketball players pre-exercise (group A), post-exercise (group B) and after 30 days on alpha-T (200 mg/24 h orally) supplementation pre- (group C) and post-training (group D). Blood samples were taken for the evaluation of total antioxidant status (TAS), alpha-T and catecholamines in plasma and S100B and muscle enzyme levels in serum.

METHODS

TAS, muscle enzymes: creatine kinase (CK), lactate dehydrogenase (LDH), and S100B protein levels were measured with commercial kits, whereas alpha-T and catecholamine levels with HPLC methods.

RESULTS

TAS was found higher in the groups with alpha-T addition (groups C and D) than in the other ones. On the contrary, CK, LDH and S100B were remarkably lower (116.8+9.5 U/L, 427+22 U/L, 0.18+0.04 microg/L, respectively) in group D than those in group B (286+12 U/L, 688+26 U/L, 0.28+0.06 microg/L, p<0.001, respectively). S100B levels were negatively correlated with TAS (r=-0.64, p<0.001) and positively with CK levels (r=0.58, p<0.001).

CONCLUSIONS

alpha-T supplementation may reduce S100B increased release from muscle and nerves induced by training. S100B serum evaluation may be a useful biomarker for the effect of training on the participation of the neuromuscular system.

Evidence for a wide extra-astrocytic distribution of S100B in human brain

Background

S100B is considered an astrocytic in-situ marker and protein levels in cerebrospinal fluid (CSF) or serum are often used as biomarker for astrocytic damage or dysfunction. However, studies on S100B in the human brain are rare. Thus, the distribution of S100B was studied by immunohistochemistry in adult human brains to evaluate its cell-type specificity.

Results

Contrary to glial fibrillary acidic protein (GFAP), which selectively labels astrocytes and shows only faint ependymal immunopositivity, a less uniform staining pattern was seen in the case of S100B. Cells with astrocytic morphology were primarily stained by S100B in the human cortex, while only 20% (14–30%) or 14% (7–35%) of all immunopositive cells showed oligodendrocytic morphology in the dorsolateral prefrontal and temporal cortices, respectively. In the white matter, however, most immunostained cells resembled oligodendrocytes [frontal: 75% (57–85%); temporal: 73% (59–87%); parietal: 79% (62–89%); corpus callosum: 93% (86–97%)]. S100B was also found in ependymal cells, the choroid plexus epithelium, vascular endothelial cells, lymphocytes, and several neurones. Anti-myelin basic protein (MBP) immunolabelling showed an association of S100B with myelinated fibres, whereas GFAP double staining revealed a distinct subpopulation of cells with astrocytic morphology, which solely expressed S100B but not GFAP. Some of these cells showed co-localization of S100B and A2B5 and may be characterized as O2A glial progenitor cells. However, S100B was not detected in microglial cells, as revealed by double-immunolabelling with HLA-DR.

Conclusion

S100B is localized in many neural cell-types and is less astrocyte-specific than GFAP. These are important results in order to avoid misinterpretation in the identification of normal and pathological cell types in situ and in clinical studies since S100B is continuously used as an astrocytic marker in animal models and various human diseases.

Serum S100B protein is increased in fasting rats

BACKGROUND

S100B is a calcium-binding protein expressed and secreted by astrocytes; serum and cerebrospinal fluid (CSF) S100B elevation has been proposed as an index of brain damage. However, other tissues are shown to produce this protein and the clinical significance of serum S100B elevation has been discussed.

METHODS

We investigated the levels of serum and CSF S100B in fasting Wistar rats. Animals were divided into two groups, control and fasting for 48 h, and S100B levels in serum and CSF were determined by ELISA. S100B secretion in dissociated epididymal fat cells was investigated in the presence of epinephrine.

RESULTS

We observed a significant >2-fold increase of S100B levels in serum of fasting rats, without changes in its CSF content. Moreover, we demonstrated in vitro epinephrine stimulated S100B release from fat cells.

CONCLUSIONS

Present results reinforce that extracerebral sources of S100B, particularly adipocytes, contribute to its serum levels and support the idea that caution is needed when interpreting serum S100B increase as a clinical marker of brain damage.

Neuroimmune-endocrine crosstalk in schizophrenia and mood disorders

This review focuses on possible causes and the impact of different immune states in schizophrenia and major depression. It discusses the fact that, in schizophrenia, an over-activation of the type 2 immune response may dominate, while the type 1 and the pro-inflammatory immune responses are over-activated in major depression. The consequence of these diverse immune states is the activation and, respectively, inhibition of different enzymes in tryptophan/kynurenine metabolism, which may lead to an overemphasis of N-methyl-D-aspartate (NMDA) receptor antagonism in schizophrenia and of NMDA-receptor agonism in depression, resulting in glutamatergic hypofunction in schizophrenia and glutamatergic hyperfunction in major depression. In addition, the activation of the type 1 and the pro-inflammatory immune responses in major depression result in increased serotonin degradation and a serotonergic deficit. While antipsychotics and antidepressants today mainly act on the dopaminergic-glutamatergic and the noradrenergic-serotonergic neurotransmission, anti-inflammatory and immune-modulating therapies might act more basically at the pathophysiological mechanism. The limitations of this concept, however, are critically discussed.

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.

S100B stimulates myoblast proliferation and inhibits myoblast differentiation by independently stimulating ERK1/2 and inhibiting p38 MAPK

The Ca2+-modulated protein of the EF-hand type, S100B, was shown to inhibit rat L6 myoblast differentiation and myotube formation by interacting with a high affinity with an unidentified receptor (Sorci et al., 2003). We show here that S100B independently inhibits the MKK6-p38 MAPK pathway and stimulates the Ras-MEK-ERK1/2 pathway. The inhibitory effect of S100B on p38 MAPK translates into a defective induction of the muscle-specific transcription factor myogenin and the antiproliferative factor p21(WAF1), while S100B's stimulatory effect on ERK1/2 results in stimulation of myoblast proliferation via cyclin D1 induction and Rb phosphorylation and protection against apoptosis via activation of NF-kappaB transcriptional activity. Also, the S100B's effects that are mediated by the Ras-MEK-ERK1/2 pathway that is, stimulation of proliferation and protection against apoptosis, depend on reactive oxygen species production, being inhibited by antioxidants, while the S100B inhibitory effect on the MKK6-p38 MAPK pathway is not. We propose that S100B might participate in the regulation of myoblast differentiation by stimulating myoblast proliferation, protecting myoblasts against apoptosis, and modulating myotube formation.

Acute and chronic electroconvulsive shock in rats: Effects on peripheral markers of neuronal injury and glial activity

Electroconvulsive therapy is considered one of the most effective treatments of major depression, but controversy still exists on whether it may be brain damaging. The aim of this work was to evaluate the cerebrospinal fluid (CSF) levels of neuron specific enolase (NSE), protein S100B and lactate of rats submitted to acute and chronic models of ECS. Rats were submitted to either one shock (acute) or a series of eight shocks, applied one at every 48 h (chronic). CSF samples were collected at 0, 3, 6, 12, 24, 48 and 72 h after the shock in the acute model and at these same time intervals after the last shock in the chronic model. Both models did not produce significant alterations in the levels of NSE. S100B levels were significantly increased at 6 h in the chronic model (p<0.0001). There was a significant increase in the levels of lactate at 0 h in both models (p<0.001). These results support the proposition that ECS does not produce neural damage, and suggest that the alterations in the levels of S100B and lactate may reflect an astrocytic activity of a protective nature.

Serum concentrations of two biochemical markers of brain tissue damage S-100B and neurone specific enolase are increased in elite female soccer players after a competitive game

BACKGROUND

It is a matter of debate whether or not ordinary heading of the ball in soccer causes injury to brain tissue.

OBJECTIVE

To analyse concentrations of the biochemical markers of brain tissue damage S-100B and neurone specific enolase (NSE) in serum of female elite soccer players in association with a competitive game.

METHODS

Venous blood samples were obtained from 44 female soccer players before and after a competitive game for analysis. The number of headers and trauma events (falls, collisions, etc) was assessed from videotape recordings for each player.

RESULTS

Concentrations of both brain damage markers were increased after the game (S-100B, 0.18 (0.11) v 0.11 (0.05) microg/l (p = 0.000); NSE, 10.14 (1.74) v 9.05 (1.59) microg/l (p = 0.001)). There was a significant correlation between changes in S-100B concentrations and both the number of headers (r = 0.430, p = 0.004) and the number of other trauma events (r = 0.517, p < 0.001).

CONCLUSION

The concentrations of both S-100B and NSE were increased by game associated activities and events. The increases in S-100B concentration were significantly related to the number of headers and other trauma events, which indicates that both these factors may have contributed to these increases.

Role of astrocytic S100β in behavioral hypersensitivity in rodent models of neuropathic pain

S100beta is a calcium-binding peptide produced mainly by astrocytes that exerts paracrine and autocrine effects on neurons and glia. We have previously shown that S100beta is markedly elevated at the mRNA level in the spinal cord following peripheral inflammation, intraplantar administration of complete Freund's adjuvant in the rat. The purpose of the present study was to further investigate the role of astrocytic S100beta in mediating behavioral hypersensitivity in rodent models of persistent pain. First, we assessed the lumbar spinal cord expression of S100beta at the mRNA and protein level using real-time RT-PCR, Western blot and immunohistochemistry analysis following L5 spinal nerve transection in rats, a rodent model of neuropathic pain. Second, we assessed behavioral hypersensitivity (mechanical allodynia) in wild type and genetically modified mice lacking or overexpressing S100beta following L5 spinal nerve transection. Third, we assessed the expression level of S100beta protein in the CD1 wild type mice after nerve injury. We report that lumbar spinal S100beta mRNA steadily increased from days 4-28 after nerve injury. S100beta protein in the lumbar spinal cord was significantly increased in both rats and mice at day 14 following nerve injury as compared with sham control groups. S100beta genetically deficient mice displayed significantly increased tactile thresholds (reduced response to non-noxious stimuli) after nerve injury as compared with the wild type group. S100beta overexpressing mice displayed significantly decreased tactile threshold responses (enhanced response to non-noxious stimuli). Together, these results from both series of experiments using a peripheral nerve injury model in two different species implicate the involvement of glial-derived S100beta in the pathophysiology of neuropathic pain.

The ischemic rat heart releases S100B

S100B is an astrocytic protein assessed in cerebrospinal fluid and serum as a biochemical marker of cerebral injuries. However, increasing evidences suggest the influence of extra cerebral sources on its serum levels. Since it was reported that the injured myocardium expresses S100B, we investigated whether the isolated heart releases this protein. The rat hearts were excised and perfused by the Langendorff technique of isolated heart perfusion. After stabilization, 10 hearts (ischemic group) were submitted to 20 minutes of ischemia and 30 minutes of reperfusion, and 5 hearts (control group) were submitted to 50 minutes of perfusion. The perfusion fluid was collected at pre-ischemia, and 0, 5, 10, 15 and 30 min after ischemia (or equivalent in controls) for S100B and cardiac troponin T (a heart injury marker) assays. In the ischemic group, S100B and troponin T levels increased significantly at time 0 min: S100B values [mug/L, median (IQ25/IQ75)] increased from < or = 0.02 (< or = 0.02/0.03) to 0.38 (0.22/0.84), while troponin T values [mug/L, median (IQ25/IQ75)] increased from 0.31 (0.15/0.45) to 2.84 (2.00/3.63). Our results point to the ischemic heart as an extra cerebral source of S100B.

Blood-brain barrier integrity may be threatened by exercise in a warm environment

Seven active men were recruited to examine changes in the serum concentration of S100beta, a proposed peripheral marker of blood-brain barrier permeability, following prolonged exercise in temperate (T) and warm (W) conditions. Subjects were seated immersed to the neck in water at 35.0 (0.1) degrees C (T) or 39.0 (0.1) degrees C (W) for 30 min. Subjects then entered a room maintained at either 18.3 (1.8) degrees C (T) or 35.0 (0.3) degrees C (W) and completed 60 min of cycle exercise at 60% peak oxygen uptake. Serum S100beta concentration was elevated after exercise in the W trial (+0.12 (0.10) microg/l; P = 0.02) but not after the T trial (P = 0.238). Water immersion and exercise elevated core temperature by 2.1 (0.5) degrees C to 39.5 (0.3) degrees C at the end of exercise in the W trial compared with a 0.9 (0.2) degrees C increase during the T trial (P < 0.001). Weighted mean skin temperature was higher throughout the W trial compared with the T trial (P < 0.001). Heart rate (P < 0.001) and blood glucose (P < 0.001) and lactate (P < 0.001) concentrations were elevated to a greater extent during exercise in the W trial than in the T trial. Ratings of perceived exertion (P < 0.001) and thermal comfort (P < 0.001) were markedly higher throughout the W trial than in the T trial. The results of this study demonstrate that serum S100beta was elevated after water immersion and prolonged exercise in a warm environment, suggesting that blood-brain barrier permeability may be altered.