A specific and sensitive ELISA for measuring S-100b in cerebrospinal fluid

Serum s100b protein levels as a neuroinflammatory biomarker of acutely relapsed paranoid schizophrenia patients

OBJECTIVE

The s100b inflammatory protein is involved in schizophrenia pathophysiology. We aim at studying the evolution of the s100b serum levels in acutely relapsed paranoid schizophrenia patients at three different time points (admission, discharge and 3 months after hospital discharge 3MAHD).

METHODS

Twenty-three paranoid schizophrenia inpatients meeting DSM-IV criteria participated in the research. Twenty-three healthy subjects matched by age, gender and season acted as the control group. Psychopathology was measured with the Positive and Negative Syndrome Scale (PANSS). Serum s100b levels were determined at 12:00 and 24:00 h with an enzyme-linked immunoassay kit.

RESULTS

Patients had significant higher serum s100b levels at admission and discharge (12:00 h) than the group of healthy subjects. At admission and discharge, s100b serum levels at 24 h had decreased compared to the 24:00 h s100b levels of the healthy subjects. At 3MAHD patients and healthy subjects had similar levels of serum s100b protein. Positive and negative PANSS scores decreased significantly between admission and discharge. Positive and negative PANSS scores decreased between discharge and 3MAHD, but these changes had no statistical significance.

CONCLUSIONS

Our study confirms that the acute inflammatory response produced in acutely relapsed patients is reversed after 3 month of hospital discharge. The variations of serum s100b concentrations when the patients suffer from an acute relapse may be a useful predictor of disease evolution.

Towards a Point-of-Care (POC) Diagnostic Platform for the Multiplex Electrochemiluminescent (ECL) Sensing of Mild Traumatic Brain Injury (mTBI) Biomarkers

Globally, 70 million people are annually affected by TBI. A significant proportion of all TBI cases are actually mild TBI (concussion, 70-85%), which is considerably more difficult to diagnose due to the absence of apparent symptoms. Current clinical practice of diagnosing mTBI largely resides on the patients' history, clinical aspects, and CT and MRI neuroimaging observations. The latter methods are costly, time-consuming, and not amenable for decentralized or accident site measurements. As an alternative (and/or complementary), mTBI diagnostics can be performed by detection of mTBI biomarkers from patients' blood. Herein, we proposed two strategies for the detection of three mTBI-relevant biomarkers (GFAP, h-FABP, and S100β), in standard solutions and in human serum samples by using an electrochemiluminescence (ECL) immunoassay on (i) a commercial ECL platform in 96-well plate format, and (ii) a "POC-friendly" platform with disposable screen-printed carbon electrodes (SPCE) and a portable ECL reader. We further demonstrated a proof-of-concept for integrating three individually developed mTBI assays ("singleplex") into a three-plex ("multiplex") assay on a single SPCE using a spatially resolved ECL approach. The presented methodology demonstrates feasibility and a first step towards the development of a rapid POC multiplex diagnostic system for the detection of a mTBI biomarker panel on a single SPCE.

A simple electrochemical immunosensor based on a chitosan/reduced graphene oxide nanocomposite for sensitive detection of biomarkers of malignant melanoma

The sensitive and specific detection of tumor biomarkers is crucial for early diagnosis and treatment of malignant melanoma. Immunoassay with a simple sensing interface and high sensitivity is highly desirable. In this work, a simple electrochemical immunosensor based on a chitosan/reduced graphene oxide (CS–rGO) nanocomposite was developed for sensitive determination of an S-100B protein, a tumor marker of malignant melanoma. CS–rGO nanocomposite were prepared by chemical reduction of graphene oxide in the presence of chitosan and modified on glassy carbon electrode (GCE) to provide a biofriendly, conductive, and easily chemically modified matrix for further immobilization of antibodies. Anti-S-100B antibodies were grafted onto the chitosan molecules to fabricate the immunorecognition interface by a simple glutaraldehyde cross-linking method. Electrochemical determination of S-100B was achieved by measuring the decreased current signal of solution phase electrochemical probes, which originated from the increased steric hindrance and insulation caused by the formation of antigen–antibody complexes at the electrode interface. Due to the good conductivity, high surface area, excellent biocompatibility, and good film-forming ability of CS–rGO, the constructed immunosensor exhibited good stability, high selectivity and sensitivity, a wide dynamic range from 10 fg mL⁻¹ to 1 ng mL⁻¹ and a low limit of detection of 1.9 pg mL⁻¹ (S/N = 3). Moreover, the sensor was also applicable for the sensitive detection of S-100B protein in real human serum samples.

Simple electrochemical immunosensor is easily fabricated based on chitosan/reduce graphene oxide nanocomposite for sensitive determination of a tumor marker of malignant melanoma.

Neuronal and glial CSF biomarkers in multiple sclerosis: a systematic review and meta-analysis

Multiple sclerosis (MS) is a neurodegenerative disease associated with inflammatory demyelination and astroglial activation, with neuronal and axonal damage as the leading factors of disability. We aimed to perform a meta-analysis to determine changes in CSF levels of neuronal and glial biomarkers, including neurofilament light chain (NFL), total tau (t-tau), chitinase-3-like protein 1 (CHI3L1), glial fibrillary acidic protein (GFAP), and S100B in various groups of MS (MS versus controls, clinically isolated syndrome (CIS) versus controls, CIS versus MS, relapsing-remitting MS (RRMS) versus progressive MS (PMS), and MS in relapse versus remission. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, we included 64 articles in the meta-analysis, including 4071 subjects. For investigation of sources of heterogeneity, subgroup analysis, meta-regression, and sensitivity analysis were conducted. Meta-analyses were performed for comparisons including at least three individual datasets. NFL, GFAP, t-tau, CHI3L1, and S100B were higher in MS and NFL, t-tau, and CHI3L1 were also elevated in CIS patients than controls. CHI3L1 was the only marker with higher levels in MS than CIS. GFAP levels were higher in PMS versus RRMS, and NFL, t-tau, and CHI3L1 did not differ between different subtypes. Only levels of NFL were higher in patients in relapse than remission. Meta-regression showed influence of sex and disease severity on NFL and t-tau levels, respectively and disease duration on both. Added to the role of these biomarkers in determining prognosis and treatment response, to conclude, they may serve in diagnosis of MS and distinguishing different subtypes.

A New Specific Method for Measuring S-100B in Serum

The S-100 family of proteins are acidic calcium and zinc binding low molecular weight proteins mainly present in astrocytes and in a population of oligodendrocytes of the CNS. S100b, an acidic low weight and zinc binding protein, has attracted considerable interest due to its release into the cerebrospinal fluid and blood from brain tissue following brain damage and from malignant melanomas. A new simple two-step incubation assay has now been elaborated in which two catcher and one tracer monoclonal antibodies are used. The specificity of this assay is high because all the MAbs used bind exclusively to S-100B, as shown by real-time biospecific interaction analyses. Moreover, the working range of the assay is 0.2–60 μg/L with a CV of less than 10%; the resulting high sensitivity has been confirmed by clinical studies. Time dependence, shaking conditions, lower limit of detection limits, effects of dilution, hook effect, recovery, impression as intra- and interassay variations, and crossreactivities with S-100A1 were tested in order to obtain a highly reproducible assay. Sera from healthy blood donors and patients undergoing cardiopulmonary bypass operations were tested with the assay. Several of the patients undergoing open heart surgery presented measurable values in this IRMA S-100 assay, indicating cerebral effects of open heart surgery. The test may be used for postoperative monitoring of these patients.

Cerebrospinal fluid levels of brain specific proteins in optic neuritis

This study evaluates levels of cerebrospinal fluid (C SF) brain-specific proteins (BSP) in subjects with optic neuritis (O N) who are at high risk of progression to multiple sclerosis (MS). Forty-one subjects had acute O N and 17 subjects with other neurological diseases (OND) served as controls. Twenty-o ne subjects with O N had white matter lesions on magnetic resonance imaging (MRI) and intrathecal synthesis of oligoclonal IgG bands (OB) consistent with being at high risk of progression to MS; eight of whom later were diagnosed with clinically definite MS (C DMS). Levels of S100B, ferritin and two neurofilament heavy chain phosphoforms (NfHSMI34 and NfHSMI35) were analysed using ELISA technique. A putative index of ‘axonal health’ was expressed as a ratio of NfHSMI34 to NfHSMI35. NfHSMI34 and the NfHSMI34:SMI35 were significantly elevated in subjects with O N compared to controls. No significant differences in levels of C SF BSP were seen between O N subjects with C DMS plus those at high risk of progression to MS and O N subjects with normal MRI and negative C SF analysis. In conclusion, there is evidence of axonal damage in subjects who present with O N, which is independent of the diagnosis of C DMS.

Evaluation of S100B in cerebrospinal fluid as a potential biomarker for neurological diseases in calves

S100B in cerebrospinal fluid (CSF-S100B) was measured in calves with 20 neurologic and 21 non-neurologic diseases to clarify its utility as a biomarker for neurologic diseases. The median CSF-S100B value in the neurologic disease group (43.0 ng/ml) was significantly higher than that in the non-neurologic disease group (10.2 ng/ml). As CSF-S100B levels in calves with neurologic diseases widely differed, the utility of CSF-S100B as a diagnostic marker for neurologic diseases in cattle remains inconclusive.

Delirium and cerebrospinal fluid S100B in hip fracture patients: a preliminary study

OBJECTIVES

Delirium is associated with an increased risk of long-term cognitive decline, suggesting the possibility of concurrent central nervous system (CNS) injury. S100B is a putative biomarker of CNS injury and elevated serum levels in delirium have been reported. Here we hypothesize that delirium is associated with raised concentrations of cerebrospinal fluid (CSF) S100B.

METHODS

Forty-five patients with hip fracture aged over 60 and awaiting surgery under spinal anesthesia were assessed for delirium pre- and post-operatively. CSF S100B levels were measured in samples collected at the onset of surgery.

RESULTS

Participants with pre-operative delirium (N = 8) had elevated Log10 CSF S100B (mean: -0.156; SD: 0.238) compared with those without delirium (mean: -0.306; SD: 0.162), Student's t-test t = 2.18, df = 43, p = 0.035.

CONCLUSIONS

This study provides preliminary evidence of elevated CSF S100B in current delirium, consistent with findings in serum and with other studies showing elevated S100B in the presence of diverse forms of CNS injury.

Intraperitoneal treatment with S100B enhances hippocampal neurogenesis in juvenile mice and after experimental brain injury

BACKGROUND

Neurogenesis is documented in adult mammals including humans, is promoted by neurotrophic factors, and constitutes an innate repair mechanism following brain injury. The glial neurotrophic protein S100B is released following various types of brain injuries, enhances hippocampal neurogenesis and improves cognitive function following brain injury in rats when applied intrathecally. The present study was designed to elucidate whether the beneficial effect of S100B on injury-induced neurogenesis can be confirmed in mice when applied intraperitoneally (i.p.), and whether this effect is dose-dependent.

METHODS

Male juvenile mice were subjected to a unilateral parietal cryolesion or sham injury, and treated with S100B at 20nM, 200nM or vehicle i.p. once daily. Hippocampal progenitor cell proliferation was quantified following labelling with bromo-deoxyuridine (BrdU, 50 mg/KG i.p.) in the germinative area of the dentate gyrus, the subgranular zone (SGZ), on day 4 as well as on cell survival and migration to the granular cell layer (GCL) on day 28. Progenitor cell differentiation was assessed following colabelling with the glial marker GFAP and the neuronal marker NeuN.

RESULTS

S100B enhanced significantly the early progenitor cell proliferation in the SGZ as well as cell survival and migration to the GCL, and promoted neuronal differentiation. While these effects were predominately dose-dependent, 200nM S100B failed to enhance the proliferation in the SGZ on day 4 post-injury.

CONCLUSION

We conclude that S100B participates in hippocampal neurogenesis after injury at lower nanomolar concentrations. Therefore S100B may serve as a potential adjunct treatment to promote neuroregeneration following brain damage.

A lack of association between elevated serum levels of S100B protein and autoimmunity in autistic children

BACKGROUND

S100B is a calcium-binding protein that is produced primarily by astrocytes. Increased serum S100B protein levels reflect neurological damage. Autoimmunity may have a role in the pathogenesis of autism in some patients. Autoantibodies may cross the blood-brain barrier and combine with brain tissue antigens, forming immune complexes and resulting in neurological damage. We are the first to investigate the relationship between serum levels of S100B protein, a marker of neuronal damage, and antiribosomal P protein antibodies in autistic children.

METHODS

Serum S100B protein and antiribosomal P antibodies were measured in 64 autistic children in comparison to 46 matched healthy children.

RESULTS

Autistic children had significantly higher serum S100B protein levels than healthy controls (P < 0.001). Children with severe autism had significantly higher serum S100B protein than patients with mild to moderate autism (P = 0.01). Increased serum levels of antiribosomal P antibodies were found in 40.6% of autistic children. There were no significant correlations between serum levels of S100B protein and antiribosomal P antibodies (P = 0.29).

CONCLUSIONS

S100B protein levels were elevated in autistic children and significantly correlated to autistic severity. This may indicate the presence of an underlying neuropathological condition in autistic patients. Antiribosomal P antibodies may not be a possible contributing factor to the elevated serum levels of S100B protein in some autistic children. However, further research is warranted to investigate the possible link between serum S100B protein levels and other autoantibodies, which are possible indicators of autoimmunity to central nervous system in autism.

Axonal damage in the making: neurofilament phosphorylation, proton mobility and magnetisation transfer in multiple sclerosis normal appearing white matter

Aims

Multiple sclerosis (MS) leaves a signature on the phosphorylation and thus proton binding capacity of axonal neurofilament (Nf) proteins. The proton binding capacity in a tissue is the major determinant for exchange between bound and free protons and thus the magnetisation transfer ratio (MTR). This study investigated whether the MTR of non-lesional white matter (NLWM) was related to the brain tissue concentration of neurofilament phosphoforms.

Methods

Unfixed post-mortem brain slices of 12 MS patients were analysed using MTR, T1 at 1.5 T. Blocks containing NLWM were processed for embedding in paraffin and inspected microscopically. Adjacent tissue was microdissected, homogenised and specific protein levels were quantified by ELISA for the Nf heavy chain (NfH) phosphoforms, glial fibrillary acidic protein (GFAP), S100B and ferritin.

Results

Averaged hyperphosphorylated NfH (SMI34) but not phosphorylated NfH (SMI35) levels were different between individual patients NLWM. The concentration of hyperphosphorylated NfH-SMI34 correlated with T1 (R = 0.70, p = 0.0114) and — inversely — with MTR (R =−0.73, p = 0.0065). NfH-SMI35 was not correlated to any of the MR indices.

Conclusions

Post-translational modifications of axonal proteins such as phosphorylation of neurofilaments occur in NLWM and may precede demyelination. The resulting change of proton mobility influences MTR and T1. This permits the in vivo detection of these subtle tissue changes on a proteomic level in patients with MS.

Proinflammatory stimuli activates human-derived enteroglial cells and induces autocrine nitric oxide production

BACKGROUND

Enteric glial cells (EGCs) have been recently indicated as key regulators of intestinal inflammation in animals. Whether or not this is true and how these cells participate to inflammatory responses in humans is unknown.

METHODS

We isolated primary EGCs from human small bowel and then, we purified and characterized those using specific glial markers, such as S100B and glial fibrillary acidic protein (GFAP). To mimic an inflammatory scenario, we exposed EGCs to exogenous stimuli, such as lipopolysaccharide and interferon-gamma (LPS and IFN-γ), alone or in combination, to evaluate glial activation [measuring GFAP, S100B level together with c-fos, major histocompatibility complex (MHC) class II, inducible nitric oxide (iNOS) proteins expression and nitric oxide (NO) production] and proliferation, respectively.

KEY RESULTS

We showed that, when challenged with a combination of LPS and IFN-γ, EGCs are significantly activated, as indicated by their positivity to c-fos and MHC class II. Similarly, pro-inflammatory stimuli significantly increase the cell proliferation rate, the expression of both S100B and GFAP, and the NO production consequent to the induction of EGCs-derived iNOS protein, with the last being dependent on S100B-RAGE (receptor for advanced glycation endproducts) interaction.

CONCLUSIONS & INFERENCES

Our data provide the first evidence that human EGCs directly respond to pro-inflammatory stimuli by changing their expression profile and by proliferating. The finding that stimulated EGCs are able to produce NO points to a role of this cell population in the scenario of intestinal inflammation.

Remote ischemic preconditioning protects the brain against injury after hypothermic circulatory arrest

BACKGROUND

Ischemic preconditioning (IPC) is a mechanism protecting tissues from injury during ischemia and reperfusion. Remote IPC (RIPC) can be elicited by applying brief periods of ischemia to tissues with ischemic tolerance, thus protecting vital organs more susceptible to ischemic damage. Using a porcine model, we determined whether RIPC of the limb is protective against brain injury caused by hypothermic circulatory arrest (HCA).

METHODS AND RESULTS

Twelve piglets were randomized to control and RIPC groups. RIPC was induced in advance of cardiopulmonary bypass by 4 cycles of 5 minutes of ischemia of the hind limb. All animals underwent cardiopulmonary bypass followed by 60 minutes of HCA at 18°C. Brain metabolism and electroencephalographic activity were monitored for 8 hours after HCA. Assessment of neurological status was performed for a week postoperatively. Finally, brain tissue was harvested for histopathological analysis. Study groups were balanced for baseline and intraoperative parameters. Brain lactate concentration was significantly lower (P<0.0001, ANOVA) and recovery of electroencephalographic activity faster (P<0.05, ANOVA) in the RIPC group. RIPC had a beneficial effect on neurological function during the 7-day follow-up (behavioral score; P<0.0001 versus control, ANOVA). Histopathological analysis demonstrated a significant reduction in cerebral injury in RIPC animals (injury score; mean [interquartile range]: control 5.8 [3.8 to 7.5] versus RIPC 1.5 [0.5 to 2.5], P<0.001, t test).

CONCLUSIONS

These data demonstrate that RIPC protects the brain against HCA-induced injury, resulting in accelerated recovery of neurological function. RIPC might be neuroprotective in patients undergoing surgery with HCA and improve long-term outcomes. Clinical trials to test this hypothesis are warranted.

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.

Increased mucosal nitric oxide production in ulcerative colitis is mediated in part by the enteroglial-derived S100B protein

In the central nervous system glial-derived S100B protein has been associated with inflammation via nitric oxide (NO) production. As the role of enteroglial cells in inflammatory bowel disease has been poorly investigated in humans, we evaluated the association of S100B and NO production in ulcerative colitis (UC). S100B mRNA and protein expression, inducible NO synthase (iNOS) expression, and NO production were evaluated in rectal biopsies from 30 controls and 35 UC patients. To verify the correlation between S100B and NO production, biopsies were exposed to S100B, in the presence or absence of specific receptor for advanced glycation end-products (RAGE) blocking antibody, to measure iNOS expression and nitrite production. S100B and iNOS expression were evaluated after incubation of biopsies with lipopolysaccharides (LPS) + interferon-gamma (IFN-gamma) in the presence of anti-RAGE or anti-S100B antibodies or budesonide. S100B mRNA and protein expression, iNOS expression and NO production were significantly higher in the rectal mucosa of patients compared to that of controls. Exogenous S100B induced a significant increase in both iNOS expression and NO production in controls and UC patients; this increase was inhibited by specific anti-RAGE blocking antibody. Incubation with LPS + IFN-gamma induced a significant increase in S100B mRNA and protein expression, together with increased iNOS expression and NO production. LPS + IFN-gamma-induced S100B up-regulation was not affected by budesonide, while iNOS expression and NO production were significantly inhibited by both specific anti-RAGE and anti-S100B blocking antibodies. Enteroglial-derived S100B up-regulation in UC participates in NO production, involving RAGE in a steroid insensitive pathway.

Molecular dissection of Alzheimer's disease neuropathology by depletion of serum amyloid P component

New therapeutic approaches in Alzheimer's disease are urgently needed. The normal plasma protein, serum amyloid P component (SAP), is always present in cerebrospinal fluid (CSF) and in the pathognomonic lesions of Alzheimer's disease, cerebrovascular and intracerebral Abeta amyloid plaques and neurofibrillary tangles, as a result of its binding to amyloid fibrils and to paired helical filaments, respectively. SAP itself may also be directly neurocytotoxic. Here, in this unique study in Alzheimer's disease of the bis(d-proline) compound, (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC), we observed depletion of circulating SAP and also remarkable, almost complete, disappearance of SAP from the CSF. We demonstrate that SAP depletion in vivo is caused by CPHPC cross-linking pairs of SAP molecules in solution to form complexes that are immediately cleared from the plasma. We have also solved the structure of SAP complexed with phosphothreonine, its likely ligand on hyperphosphorylated tau protein. These results support further clinical study of SAP depletion in Alzheimer's disease and potentially other neurodegenerative diseases.

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.

Biological and methodological features of the measurement of S100B, a putative marker of brain injury

The S100B astroglial protein is widely used as a parameter of glial activation and/or death in several conditions of brain injury. Cerebrospinal fluid and serum S100B variations have been proposed to evaluate clinical outcomes in these situations. Here, we briefly broach some aspects, commonly not sufficiently valorized, concerning the biology and measurements of this protein. S100B has molecular targets and activities in and outside of astrocytes, and variations of intra and extracellular content are not necessarily coupled. We discuss the extracellular origin of this protein in brain tissue, as well as extracerebral sources of this protein in serum, comparing it with other available protein markers of brain damage. The superestimation of the heterodimer S100A1-B in the current clinical literature is also analyzed. We affirm that poor dualistic views that consider S100B elevation as "bad" or "good" simplify clinical practice and delay our comprehension of the role of this protein, both in physiological conditions and in brain disorders.

Evaluation of an alternative S100b assay for use in cardiac surgery: relationship with microemboli and neuropsychological outcome

INTRODUCTION

The aim of the study was to investigate the relationship between S100b release, neuropsychological outcome and cerebral microemboli. Peri-operative assay of the astroglial cell protein S100b has been used as a marker of cerebral damage after cardiac surgery but potential assay cross-reactivity has limited its specificity. The present study uses an alternative enzyme-linked immunoabsorbant assay (ELISA) for serum S100b that has documented sensitivity and specificity data in patients undergoing coronary artery bypass grafting (CABG).

METHODS

Fifty-five consecutive patients undergoing routine CABG surgery received serial venous S100b sampling at five time points: i) Pre-operative, ii) At the end of cardiopulmonary bypass (CPB), iii) 6 hrs, iv) 24 hrs and v) 48 hrs post skin closure. A previously described sandwich ELISA with monoclonal anti- S100b was used. This assay has a lower limit of detection of 0.04 microg/L and < 0.006% reactivity with S100a at a concentration of 100 microg/L S100a. Cerebral microemboli during surgery were recorded by transcranial Doppler monitor over the right middle cerebral artery. Evidence of cerebral impairment was obtained by comparing patients' performance in a neuropsychological battery of 9 tests administered 6-8 weeks post-operatively with their pre-operative scores.

RESULTS

There was a significant increase in S100b only at the end of bypass (mean 0.30 microg/L, SD +/- 0.33 and range .00 to 1.57). S100b levels at the end of bypass did not correlate with neuropsychological outcome or microemboli counts.

CONCLUSIONS

The low levels of S100b detected using the present assay, despite its high sensitivity and despite the routine use of cardiotomy suction, suggest that the assay may have higher specificity for cerebral S100b than previously used assays. There was no evidence that this assay is related to neuropsychological change or cerebral microemboli in cardiac surgery.

Cerebrospinal Fluid Studies in Kenyan Children with Severe Falciparum Malaria

The pathogenesis of the neurological complications of Plasmodium falciparum malaria is unclear. We measured proteins and amino acids in paired plasma and cerebrospinal fluid (CSF) samples in children with severe falciparum malaria, to assess the integrity of the blood brain barrier (BBB), and look for evidence of intrathecal synthesis of immunoglobulins, excitotoxins and brain damage. METHODS: Proteins of different molecular sizes and immunoglobulins were measured in paired CSF and plasma samples in children with falciparum malaria and either impaired consciousness, prostrate, or seizures. RESULTS: The ratio of CSF to plasma albumin (Q(alb)) exceeded the reference values in 42 (51%) children. The CSF concentrations of the excitotoxic amino acid aspartate and many non-polar amino acids, except alanine, were above the reference value, despite normal plasma concentrations. IgM concentrations were elevated in 21 (46%) and the IgM index was raised in 22 (52%). Identical IgG oligoclonal bands were found in 9 (35%), but only one patient had an increase in the CSF IgG without a concomitant increase in plasma indicating intrathecal synthesis of IgG. CONCLUSIONS: This study indicates that the BBB is mildly impaired in some children with severe falciparum malaria, and this impairment is not confined to cerebral malaria, but also occurs in children with prostrate malaria and to a lesser extent the children with malaria and seizures. There is evidence of intrathecal synthesis of immunoglobulins in children with malaria, but this requires further investigation. This finding, together with raised level of excitotoxic amino acid aspartate could contribute to the pathogenesis of neurological complications in malaria.

Cerebrospinal fluid brain specific proteins in relation to nitric oxide metabolites during relapse of multiple sclerosis

This study investigated the cerebrospinal fluid (CSF) levels of ferritin, S100B as biomarkers for glial activation and NfH(SM135)--a biomarker of axonal damage--in relation to nitric oxide (NO) metabolites: nitrate and nitrite (NOx) during acute multiple sclerosis (MS) relapse. Thirty-four relapsing-remitting MS (RR-MS) patients during acute relapse and 12 controls were enrolled. Patients were assessed on Expanded Disability Status Scale (EDSS) and underwent lumbar puncture within two weeks following relapse. Twenty patients were available for further follow-up and were assessed on EDSS 6-8 weeks since the relapse onset. The CSF NOx (P<0.0001), NfH(SM135) (P=0.01) and S100B (P=0.009) but not ferritin (P>0.05) were significantly raised in MS group. There was a significant correlation between CSF ferritin and S100B in RR-MS group (P=0.004). CSF NOx did not correlate with S100B and ferritin in study groups. RR-MS patients with detectable NfH(SM135) levels had higher NOx compared with subjects having undetectable NfH(SM135) (P=0.03). In the follow-up study, raised baseline levels of NOx (P=0.016) or NfH(SM135) (P=0.04) inversely correlated with the clinical recovery grade expressed as relative EDSS change between baseline and follow-up. In conclusion, NO metabolites were increased and because of their correlation with a biomarker of axonal degeneration (neurofilaments) and a measure for clinical disability (EDSS), relapse-related nitrosative stress is likely to be relevant to the development of sustained disability in an individual patient.

Enteric glial-derived S100B protein stimulates nitric oxide production in celiac disease

BACKGROUND & AIMS

Enteric glia participates to the homeostasis of the gastrointestinal tract. In the central nervous system, increased expression of astroglial-derived S100B protein has been associated with the onset and maintaining of inflammation. The role of enteric glial-derived S100B protein in gastrointestinal inflammation has never been investigated in humans. In this study, we evaluated the expression of S100B and its relationship with nitric oxide production in celiac disease.

METHODS

Duodenal biopsy specimens from untreated and on gluten-free diet patients with celiac disease and controls were respectively processed for S100B and inducible nitric oxide synthase (iNOS) protein expression and nitrite production. To evaluate the direct involvement of S100B in the inflammation, control biopsy specimens were exposed to exogenous S100B, and iNOS protein expression and nitrite production were measured. We also tested gliadin induction of S100B-dependent inflammation in cultured biopsy specimens deriving from on gluten-free diet patients in the absence or presence of the specific S100B antibody.

RESULTS

S100B messenger RNA and protein expression, iNOS protein expression, and nitrite production were significantly increased in untreated patients but not in on gluten-free diet patients vs controls. Addition of S100B to control biopsy specimens resulted in a significant increase of iNOS protein expression and nitrite production. In celiac disease patients but not in controls biopsy specimens, gliadin challenge significantly increased S100B messenger RNA and protein expression, iNOS protein expression, and nitrite production, but these effects were completely inhibited by S100B antibody.

CONCLUSIONS

Enteric glial-derived S100B is increased in the duodenum of patients with celiac disease and plays a role in nitric oxide production.

Astrocytic activation in relation to inflammatory markers during clinical exacerbation of relapsing-remitting multiple sclerosis

The study aimed to assay the cerebrospinal fluid (CSF) levels of protein S100B, a biomarker of astrocyte activation in relation to kynurenic acid (KYNA) and nitric oxide (NO) metabolites, nitrate/nitrite (NOx) concentrations in acute relapse multiple sclerosis (MS) patients. Twenty relapsing-remitting MS (RR-MS) patients and 10 controls were enrolled. RR-MS patients were assessed on the expanded disability status scale (EDSS) and underwent lumbar puncture. The CSF KYNA, NOx and S100B levels were significantly higher in RR-MS group compared to controls (p = 0.01, 0.001, 0.04, respectively). There was a significant correlation between CSF S100B and KYNA (p = 0.01) but not NOx (p > 0.05) in RR-MS. CSF KYNA, NOx or S100B concentrations did not correlate with disease characteristics of MS patients. Our study suggests the activation of the kynurenine pathway leading to the increase of neuroprotective KYNA in the CSF of MS patients during acute relapse what contrasts with chronic phases of the disease.

Influence of timing on CSF tests value for Creutzfeldt-Jakob disease diagnosis

Background

The analysis of markers in the cerebrospinal fluid (CSF) is useful in the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). However, the time at which the study of these markers is most sensitive remains controversal.

Objective

To assess the influence of time of sampling on the value of CSF tests in the diagnosis of sCJD.

Method

In the framework of a multinational European study, we studied the results of 14-3-3, S100b, neurone specific enolase (NSE) and tau protein in 833 CSF samples from sCJD patients at different stages of disease and in 66 sequentially repeated lumbar punctures (LP).

Results

14-3-3 and tau protein tended to increase in sensitivity from onset (88%, 81%) to the advanced stage (91%, 90%). This was significant only in the methionine-valine (MV) heterozygous group of patients at codon 129. The absolute levels of S100b (p < 0.05), NSE and tau protein increased in the last stage of disease. High levels of tau protein, NSE and S100b were associated with shorter survival times (p < 0.01). Sixty-six sCJD patients underwent repeated LP. These sCJD patients were younger, had longer disease durations and were more frequently MV at codon 129 (p < 0.001) than the whole group. 14-3-3 sensitivity increased from 64% to 82% in the second LP (p = 0.025) and 88% sCJD patients had at least one positive result.

Conclusions

Sensitivity and absolute levels of CJD markers increased with disease progression and were modulated by the codon 129 genotype. Early negative results should be inter-preted with caution, especially in young patients or those who are MV at codon 129.

Activin A Release into Cerebrospinal Fluid in a Subset of Patients with Severe Traumatic Brain Injury

Activin A is a member of the transforming growth factor-beta superfamily and has been demonstrated to be elevated during inflammation and to have neuroprotective properties following neural insults. In this study, we examined whether traumatic brain injury (TBI) induced a response in activin A or in the concentrations of its binding protein, follistatin. Thirty-nine patients with severe TBI had daily, matched cerebrospinal fluid (CSF) and serum samples collected post-TBI and these were assayed for activin A and follistatin using specific immunoassays. Concentrations of both molecules were assessed relative to a variety of clinical parameters, such as the Glasgow Coma Score, computer tomography classification of TBI, measurement of injury markers, cell metabolism and membrane breakdown products. In about half of the patients, there was a notable increase in CSF activin A concentrations in the first few days post-TBI. There were only minor perturbations in either serum activin or in either CSF or serum follistatin concentrations. The CSF activin A response was not related to any of the common TBI indices, but was strongly correlated with two common markers of brain damage, neuronal specific enolase and S100-beta. Further, activin A levels were also associated with indices of metabolism, such as lactate and pyruvate, excitotoxicity (glutamate) and membrane lipid breakdown products such as glycerol. In one of the two patients who developed a CSF infection, activin A concentrations in CSF became markedly elevated. Thus, some TBI patients have an early release of activin A into the CSF that may result from activation of inflammatory and/or neuroprotective pathways.

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.

Amniotic fluid brain-specific proteins are biomarkers for spinal cord injury in experimental myelomeningocele

Myelomeningocele (MMC), the most severe form of spina bifida (SB), causes neurological deficit. Injury to the spinal cord is thought to begin in utero. We investigated whether brain-specific proteins (BSPs) would enable us to monitor the development of MMC-related tissue damage during pregnancy in an animal model with naturally occurring SB (curly tail/loop tail mouse; n = 256). Amniotic fluid levels of neurofilament heavy chain (NfH), glial acidic fibrillary protein (GFAP) and S100B were measured by standard ELISA techniques. The amniotic fluid levels of all BSPs were similar in SB and control mice on embryonic day (E) 12.5 and 14.5, whereas a significant increase was observed for GFAP in SB mice on E16.5. Levels of all BSPs were significantly increased in SB mice on E18.5. The rapid increase in GFAP, paralleled by a moderate increase in NfH and S100B, suggests that spinal cord damage starts to accelerate around E16.5. The macroscopic size of the MMC was related to NfH level on E16.5 and E18.5, suggesting that axonal degeneration is most severe in large MMC. Amniotic fluid BSP measurements may provide important information for balancing the risks and benefits to mother and child of in utero surgery for MMC.

Assessment of cerebral S100B levels by proton magnetic resonance spectroscopy after lateral fluid-percussion injury in the rat

Object. After traumatic brain injury (TBI), S100B protein is released by astrocytes. Furthermore, cerebrospinal fluid (CSF) and serum S100B levels have been correlated to outcome. Given that no data exist about the temporal profile of cerebral S100B levels following TBI and their correlation to serum levels, the authors examined whether proton magnetic resonance (MR) spectroscopy is capable of measuring S100B.

Methods. Results of in vitro proton MR spectroscopy experiments (2.35-tesla magnet, 25 G/cm, point-resolved spatially localized spectroscopy) revealed an S100B-specific peak at 4.5 ppm and confirmed a positive correlation between different S100B concentrations (10 nM–1 µM) and the area under the curve (AUC) for the S100B peak (r = 0.991, p < 0.001). Thereafter, proton MR spectroscopy was performed in male Sprague—Dawley rats (7 × 5 × 5—mm voxel in each hemisphere, TR 3000 msec, TE 30 msec, 256 acquisitions). Exogenously increased CSF S100B levels (∼ 200 ng/ml) through the intraventricular infusion of S100B increased the AUC of the S100B peak from 0.06 ± 0.02 to 0.44 ± 0.06 (p < 0.05), whereas serum S100B levels remained normal. Two hours after lateral fluid-percussion injury, serum S100B levels increased to 0.61 ± 0.09 ng/ml (p < 0.01) and rapidly returned to normal levels, whereas the AUC of the S100B peak increased to 0.19 ± 0.04 at 2 hours postinjury and 0.41 ± 0.07 (p < 0.05) on Day 5 postinjury.

Conclusions. Proton MR spectroscopy proves a strong correlation between the AUC of the S100B peak and S100B concentrations. Following experimental TBI, serum S100B levels increased for only a very short period, whereas cerebral S100B levels were increased up to Day 5 postinjury. Given that experimental data indicate that S100B is actively released following TBI, proton MR spectroscopy may represent a new tool to identify increased cerebral S100B levels in patients after injury, thus allowing its biological function to be better understood.

Cerebrospinal Fluid S-100B Concentrations in Normal and Diseased Cattle

We measured the concentrations of S-100B, a marker protein used in humans to detect brain damage, in the cerebrospinal fluid (CSF) of clinically normal cattle (n=15, mean age +/- SD: 31.8 +/- 37.5 months) and of cattle with various inflammatory disorders (n=43, 70.6 +/- 31.9 months). The mean +/- SD CSF S-100B level was 2.9 +/- 1.6 ng/ml in the normal group and 7.0 +/- 7.4 ng/ml in the diseased group. Thirteen diseased cattle that had developed no obvious neurological signs showed abnormally high S-100B concentrations (> 8.0 ng/ml), whereas the two cattle with neurological disorders did not. No particular disease could be related to the S-100B rise. Therefore, it remains inconclusive whether measurement of CSF S-100B concentration is useful in veterinary neurological diagnosis.

Treatment response in relation to inflammatory and axonal surrogate marker in multiple sclerosis

BACKGROUND

This study aimed to investigate if treatment response could retrospectively be related to inflammatory or axonal pathology as measured by plasma surrogate markers.

METHODS

In this 1-year observational study 30 multiple sclerosis (MS) patients with relapsing-remitting disease were treated with intramuscular IFNbeta-1a or subcutaneous IFNbeta-1b. Responders and nonresponders were defined according to clinical and magnetic resonance imaging criteria. The control group consisted of 14 healthy subjects. Plasma levels of surrogate markers for inflammation (nitric oxide metabolites (NOx)), astrocytic activation (S100B) and axonal damage (NfH(SM135)) were measured using standard assays.

RESULTS

There were 11 nonresponders and 19 responders to IFNbeta treatment. Median S100B levels were elevated in a higher proportion of treatment responders (63%, 42.9 pg/mL) compared to nonresponders (18%, 11.7 pg/mL, P < 0.05, Fisher's exact test) and controls (0%, 2 pg/mL, P < 0.001). Levels of NOx were found to be more frequently elevated in nonresponders (72%, 39 microM) compared to healthy controls (0%, 37 microM, P < 0.05). Levels of NfH(SM135) were more frequently elevated in responders (58%, 300 pg/mL, P < 0.001) and nonresponders (72%, 500 pg/mL, P < 0.001) compared to controls (0%, 4.5 pg/mL).

CONCLUSION

Patients with relapsing-remitting MS who had surrogate marker supported evidence for astrocytic activation responded more frequently to treatment with IFNbeta.

Serum S100B in primary progressive multiple sclerosis patients treated with interferon-beta-1a

S100B belongs to a family of calcium-binding proteins implicated in intracellular and extracellular regulatory activities. This study of serum S100B in primary progressive multiple sclerosis (PPMS) is based on data obtained from a randomized, controlled trial of Interferon beta-1a in subjects with PPMS. The key questions were whether S100B levels were associated with either disability or MRI findings in primary progressive MS and whether Interferon beta-1a has an effect on their S100B levels. Serial serum S100B levels were measured using an ELISA method. The results demonstrated that serum S100B is not related to either disease progression or MRI findings in subjects with primary progressive MS given Interferon beta-1a. Furthermore there is no correlation between S100B levels and the primary and secondary outcome measures.

Intraventricular Infusion of the Neurotrophic Protein S100B Improves Cognitive Recovery after Fluid Percussion Injury in the Rat

Elevated serum S100B levels have been shown to be a predictor of poor outcome after traumatic brain injury (TBI). Experimental data, on the other hand, demonstrate a neuroprotective and neurotrophic effect of this calcium-binding protein. The purpose of this study was to examine the role of increased S100B levels on functional outcome after TBI. Following lateral fluid percussion or sham injury in male Sprague Dawley rats (n = 56), we infused S100B (50 ng/h) or vehicle into the cerebrospinal fluid of the ipsilateral ventricle for 7 days using an osmotic mini-pump. Assessment of cognitive performance by the Morris water maze on days 30-34 after injury revealed an improved performance of injured animals after S100B infusion (p < 0.05), when compared to vehicle infusion. Blood samples for analysis of clinical markers of brain damage, S100B and neuron specific enolase, taken at 30 min, 3 h, 4 h, 2 days, or 5 days showed a typical peak 3 h after injury (p < 0.01), and higher serum levels correlated significantly with an impaired cognitive recovery (p < 0.01). The correlation of higher serum S100B levels with poor water maze performance may result from injury induced opening of the blood-brain barrier, allowing the passage of S100B into serum. Thus while higher serum levels of S100B seem to reflect the degree of blood-brain barrier opening and severity of injury, a beneficial effect of intraventricular S100B administration on long-term functional recovery after TBI has been demonstrated for the first time. The exact mechanism by which S100B exerts its neuroprotective or neurotrophic influence remains unknown and needs to be elucidated by further investigation.

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.

Cerebrospinal fluid (CSF) and serum S100B: release and wash-out pattern

S100B is an important brain specific protein for monitoring damage and activation of astrocytes. Using a straight forward, non-resource demanding in-house ELISA technique we measured S100B in cerebrospinal fluid (CSF) and serum in patients with traumatic brain injury (TBI) (serum), subarachnoid hemorrhage (SAH) (CSF, serum), intracranial hemorrhage (ICH) (CSF, serum), normal controls (NC) (serum) and a reference population (CSF, N=409). The release and wash-out pattern found in CSF and serum are discussed in relation to the three main determinants for increased brain specific protein levels in body fluids: (i) total mass effect; (ii) pathology; and (iii) time effect.

Quantification of neurodegeneration by measurement of brain-specific proteins

Quantification of neurodegeneration in animal models is typically assessed by time-consuming and observer-dependent immunocytochemistry. This study aimed to investigate if newly developed ELISA techniques could provide an observer-independent, cost-effective and time-saving tool for this purpose. Neurofilament heavy chain (NfH(SM135)), astrocytic glial fibrillary acidic protein (GFAP), S100B and ferritin, markers of axonal loss, gliosis, astrocyte activation and microglial activation, respectively, were quantified in the spinal cord homogenates of mice with chronic relapsing experimental allergic encephalomyelitis (CREAE, n=8) and controls (n=7). Levels of GFAP were found to be threefold elevated in CREAE (13 ng/mg protein) when compared to control animals (4.5 ng/mg protein, p<0.001). The inverse was observed for NfH(SM135) (21 ng/mg protein vs. 63 ng/mg protein, p<0.001), ferritin (542 ng/mg protein vs. 858 ng/mg protein, p<0.001) and S100B (786 ng/mg protein vs. 2080 ng/mg protein, N.S.). These findings were confirmed by immunocytochemistry, which demonstrated intense staining for GFAP and decreased staining for NfH(SM135) in CREAE compared to control animals. These findings indicate that axonal loss and gliosis can be estimated biochemically using the newly developed ELISA assays for NfH(SM135) and GFAP. These assays may facilitate the quantification of pathological features involved in neurodegeneration.

Cerebrospinal fluid apolipoprotein E concentration decreases after traumatic brain injury

The APOE epsilon4 allele has been associated with unfavorable outcome after several types of acute brain injury, yet the biological mechanisms underlying this observation are poorly understood. Postmortem and experimental brain injury studies suggest the presence of increased amounts of apolipoprotein E (apoE) within the neuropil after acute brain injury. We assayed the concentration of apolipoprotein E in the cerebrospinal fluid (CSF) of non-injured controls and patients with traumatic brain injury (TBI) to determine whether differences exist, and if these differences correlate with injury severity and clinical outcome. CSF apoE and S100B, a marker of injury severity, were measured by enzyme linked immunosorbant assay. CSF was sampled from 27 traumatic brain injury patients (mean age 32, median 25, range 16-65 years) within 3 days of injury, and 28 controls (mean age 40, median 37, range 19-73 years). The TBI patients all had a Glasgow Coma Score (GCS) of less than eight (i.e., severe head injury). Clinical outcome was determined using the Glasgow Outcome Score (GOS). The average concentration of apoE in the CSF of controls was 12.4 mg/L (95% CI: 10.5-14.3 mg/L) and in TBI patients was 3.7 mg/L (95% CI: 2.1-4.1 mg/L; Mann-Whitney: p < 0.0001). In contrast, the concentration of S100B in the CSF of TBI patients was significantly higher than that of controls (Mann-Whitney: p < 0.0001). We speculate that apoE is retained within the parenchyma of the central nervous system in response to injury where in view of previous data, it may have a protective role.

Decreased cerebrospinal fluid apolipoprotein E after subarachnoid hemorrhage: correlation with injury severity and clinical outcome

BACKGROUND AND PURPOSE

The apolipoprotein E (APOE) epsilon4 allele has been associated with unfavorable outcome after subarachnoid hemorrhage (SAH), suggesting that apoE plays an important role in the response of the brain to SAH. We determined the concentration of apoE in the cerebrospinal fluid (CSF) of patients with SAH and a control group to test the hypothesis that alterations in CSF apoE reflect the response of the brain to SAH and are correlated with the severity of injury and outcome.

METHODS

ApoE and S100B (a marker of brain injury) were measured by ELISA in CSF from a non-brain-injured control group and patients with SAH. The severity of SAH was determined from the Glasgow Coma Scale, and the clinical outcome was determined from the Glasgow Outcome Scale.

RESULTS

In contrast to increased CSF concentration of S100B, CSF apoE concentration was significantly lower in patients after SAH than in control subjects (Mann-Whitney test, P<0.0001). SAH patients with more severe injury and less favorable outcome had lower CSF apoE concentration than did patients with milder injury and better clinical outcome (Fisher exact test, P=0.02).

CONCLUSIONS

The concentration of apoE in the CSF decreases after SAH, despite the likely leakage of plasma apoE into the CSF. We speculate that apoE is retained within the parenchyma of the central nervous system in response to injury, where, in view of previous data, it may have a protective role.

Cerebrospinal fluid S100B correlates with brain atrophy in Alzheimer's disease

S100B is a predominantly astrocytic protein with dose-dependent cytotoxic and neurotrophic properties encoded on chromosome 21q22.3. Concentrations of S100B were measured in the cerebrospinal fluid (CSF) of 31 patients with Alzheimer's disease (AD), 36 patients with frontotemporal lobe dementia (FTLD) and 49 patients with other non-inflammatory neurological diseases. Additional CSF S100B concentrations were correlated with normalised brain volume measurements in AD and FTLD. CSF S100B was significantly higher in AD (Mean+/-standard deviation=0.4+/-0.2 ng/ml) and FTLD (0.42+/-0.19 ng/ml) patients when compared with control subjects (0.25+/-0.08, P<0.001). In patients with AD, S100B correlated negatively with normalised brain volume (R(S)=-0.53, P<0.001). No such correlation was found for FTLD patients. This study supports the concept that S100B is of pathological relevance for degeneration of the central nervous system in AD.

Effects of ethanol and 5-HT1A agonists on astroglial S100B

Previous studies from this and another laboratory demonstrated that in utero ethanol exposure reduces 5-HT neurons and S100B-immunopositive glia that are proximal to these neurons. Our laboratory also found that these effects are prevented by maternal treatment with a 5-HT(1A) agonist. Because of S100B's important role in the development of 5-HT neurons, the present study used both in vivo and in vitro models to investigate the potential involvement of S100B with the damaging effects of ethanol and with the protective effects of 5-HT(1A) agonists. We used in situ hybridization to address whether a 5-HT(1A) agonist could potentially affect S100B mRNA in vivo. Maternal treatment with buspirone between gestation days 13 and 20 significantly increased S100B mRNA in neuroepithelium of G20 offspring of control (40%) and ethanol-fed dams (20%). However, S100B mRNA was not altered in neuroepithelium from ethanol-exposed offspring. In astroglial cultures, we examined whether ethanol reduces the release of S100B and whether a 5-HT(1A) agonist could stimulate the release of this protein. We also evaluated the effects of ethanol and ipsapirone on astroglial content of S100B. Neither the concentration of S100B in astroglial media nor astroglial content of S100B were affected by ethanol. However, treatment with 100 nM ipsapirone, a 5-HT(1A) agonist, between the 6th and 7th day in vitro, increased astroglial release of S100B 2- to 3-fold. Thus, the protective effects of a 5-HT(1A) agonist on ethanol-treated 5-HT neurons might be associated with the ability of these drugs to release the neurotrophic factor S100B from astrocytes.

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

OBJECTIVE

To investigate whether serum S100B is suitable as a sensitive biomarker for early prediction of increased intracranial pressure and mortality rates after brain injury.

DESIGN

A prospective, longitudinal study.

SETTING

Neurosurgical intensive care unit.

PATIENTS

Twenty-one patients with acute brain injury and 13 healthy controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We assessed Glasgow Coma Scale score and pupil reaction on admission and quantified serum S100B (in-house enzyme-linked immunosorbent assay) and intracranial pressure on admission and the subsequent 6 days. Serum S100B concentrations on admission and day 1 were significantly higher in patients with fatal outcome (p <.05, p<.01, respectively), with a sensitivity of 100% and a specificity of 75-83%. Patients with high serum S100B on admission had an eight-fold and on day 1 a 12-fold increased relative risk of a fatal outcome. Subsequent serum S100B values predicted the development of high intracranial pressure in patients with traumatic brain injury (p <.01). Patients with high intracranial pressure on day 5 had an 11-fold and on day 6 a nine-fold increased risk of fatal outcome.

CONCLUSIONS

Serum S100B is a sensitive biomarker for early prediction of the development of high intracranial pressure and fatal outcome following acute brain injury. Monitoring S100B concentrations could contribute to early detection of patients at risk of secondary increases in intracranial pressure and subsequent mortality. This would allow earlier targeting of therapy in selected patients.

Cerebrospinal fluid S100B is elevated in the earlier stages of Alzheimer's disease

Postmortem demonstration of increased expression of biologically active S100B in Alzheimer's disease (AD) and its relation to progression of neuropathological changes across the cortical regions suggests involvement of this astrocytic cytokine in the pathophysiology of AD. The hypothesis that the overexpression of S100B in Alzheimer brain is related to the progression of clinical symptoms was addressed in living persons by measuring S100B concentrations in cerebrospinal fluid (CSF) from AD patients with a broad range of clinical dementia severity and from healthy older persons. The effect of normal aging on CSF S100B concentrations also was estimated. CSF S100B did not differ between all 68 AD subjects (0.98+/-0.09 ng/ml (mean+/-S.E.M.)) and 25 healthy older subjects (0.81+/-0.13 ng/ml). When AD subjects were divided into mild/moderate stage and advanced stage clinical dementia severity by the established Clinical Dementia Rating Scale (CDR) criteria, S100B was significantly higher in the 46 mild/moderate stage AD subjects (1.17+/-0.11 ng/ml) than in either the 22 advanced stage AD subjects (0.60+/-0.12 ng/ml) or the healthy older subjects. Consistent with higher CSF S100B in mild to moderate AD, there was a significant correlation among all AD subjects between CSF S100B and cognitive status as measured by the Mini Mental State Exam (MMSE) score. CSF S100B did not differ between healthy older subjects and healthy young subjects. These results suggest increased CNS expression of S100B in the earlier stages of AD, and are consistent with a role for S100B in the initiation and/or facilitation of neuritic plaque formation in AD brain.

Use of 14-3-3 and other brain-specific proteins in CSF in the diagnosis of variant Creutzfeldt-Jakob disease

OBJECTIVES

The detection of the protein 14-3-3 in the CSF has been shown to be a reliable and sensitive marker for sporadic Creutzfeldt-Jakob disease (CJD). Other brain-specific proteins such as neuron specific enolase (NSE), S-100b, and tau protein have also been reported to be increased in the CSF of patients with sporadic CJD. In 1996 a variant of CJD (vCJD) was described which is likely to be causally linked to the bovine spongiform encephalopathy agent. This study reports and compares the findings of CSF brain specific protein analysis in 45 patients with vCJD and in 34 control patients.

METHODS

The CSF from 45 patients with vCJD and 34 controls were investigated for the presence of 14-3-3 by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting with chemiluminescent detection. Tau protein, S-100b, and NSE concentrations in CSF were measured using enzyme immunoassays.

RESULTS

Protein 14-3-3 was detected in the CSF of 22/45 patients with vCJD and in 3/34 controls. The mean concentrations of NSE, S-100b, and tau protein in CSF were significantly raised in patients with vCJD compared with controls. The positive predictive value of CSF 14-3-3 was 86% and the negative predictive value was 63%. These values are lower than those reported for sporadic CJD. An increased CSF tau had a positive predictive value of 93% and a negative predictive value of 81%. The combination of CSF 14-3-3 and/or increased CSF tau had a positive predictive value of 91% and a negative predictive value of 84%.

CONCLUSIONS

CSF protein 14-3-3 is not as useful a marker for vCJD as it is for sporadic CJD. Increased concentration of CSF tau was found to be a sensitive marker of vCJD but as concentrations may be increased in many forms of non-CJD dementia, this may limit its usefulness as a diagnostic test.

Increased serum S100B protein in schizophrenia: a study in medication-free patients

S100B protein, a calcium binding protein produced and released by glial cells, has been used as a sensitive marker of brain damage. Previous studies have found alterations in peripheral S100B levels in schizophrenic patients on medication. We compared serum S100B levels of 20 medication-free DSM-IV schizophrenic patients and 20 age-gender matched healthy controls. Schizophrenic patients presented higher serum S100B levels (mean 0.120 ng/ml+/-S.D. 0.140) compared to controls (mean 0.066 ng/ml+/-S.D. 0.067; P=0.014) and there was a negative correlation with illness duration (r=-0.496, P=0.031). The results of this study indicate that serum S100B levels may be a state marker of a limited neurodegenerative process, particularly in the early course of schizophrenia or, at least, in a subgroup of schizophrenic patients.

Immunocontent and secretion of S100B in astrocyte cultures from different brain regions in relation to morphology

Primary astrocyte cultures prepared from neonatal hippocampus, cerebral cortex and cerebellum were morphologically distinct. Cells from hippocampus and cortex were almost entirely protoplasmic, whereas cerebellar astrocytes had many processes; in the absence of serum these differences were accentuated. We compared the immunocontent and secretion of the mitogenic protein S100B in these cultures. Immunocontent was 2.5 times higher in cerebellar astrocytes than in hippocampal or cortical astrocytes. Cells from all three regions secreted S100B under basal conditions, but the secretion rate was higher in cerebellar astrocytes. Secretion depended on protein synthesis and was increased by incubation with forskolin or lysophosphatidic acid in mechanisms which were additive. The stellate morphology induced by forskolin was reversed by lysophosphatidic acid in hippocampal but not in cerebellar cultures, suggesting that S100B secretion was not associated with a process-bearing phenotype of astrocytes.