Brain-derived protein concentrations in the cerebrospinal fluid: contribution of trauma resulting from ventricular drain insertion

Proteomic profile and predictive markers of outcome in patients with subarachnoid hemorrhage

BACKGROUND

The molecular mechanisms underlying development of posthemorrhagic hydrocephalus (PHH) following subarachnoid hemorrhage (SAH) remain incompletely understood. Consequently, treatment strategies tailored towards the individual patient remain limited. This study aimed to identify proteomic cerebrospinal fluid (CSF) biomarkers capable of predicting shunt dependency and functional outcome in patients with SAH in order to improve informed clinical decision making.

METHODS

Ventricular CSF samples were collected twice from 23 patients with SAH who required external ventricular drain (EVD) insertion (12 patients with successful EVD weaning, 11 patients in need of permanent CSF shunting due to development of PHH). The paired CSF samples were collected acutely after ictus and later upon EVD removal. Cisternal CSF samples were collected from 10 healthy control subjects undergoing vascular clipping of an unruptured aneurysm. All CSF samples were subjected to mass spectrometry-based proteomics analysis. Proteomic biomarkers were quantified using area under the curve (AUC) estimates from a receiver operating curve (ROC).

RESULTS

CSF from patients with SAH displayed a distinct proteomic profile in comparison to that of healthy control subjects. The CSF collected acutely after ictus from patients with SAH was moreover distinct from that collected weeks later but appeared similar in the weaned and shunted patient groups. Sixteen unique proteins were identified as potential predictors of shunt dependency, while three proteins were identified as potential predictors of functional outcome assessed six months after ictus with the modified Rankin Scale.

CONCLUSIONS

We here identified several potential proteomic biomarkers in CSF from patients with SAH capable of predicting (i) shunt dependency and thus development of PHH and (ii) the functional outcome assessed six months after ictus. These proteomic biomarkers may have the potential to aid clinical decision making by predicting shunt dependency and functional outcome following SAH.

How S100B crosses brain barriers and why it is considered a peripheral marker of brain injury

S100B is a 21-kDa protein that is produced and secreted by astrocytes and widely used as a marker of brain injury in clinical and experimental studies. The majority of these studies are based on measurements in blood serum, assuming an associated increase in cerebrospinal fluid and a rupture of the blood-brain barrier (BBB). Moreover, extracerebral sources of S100B are often underestimated. Herein, we will review these interpretations and discuss the routes by which S100B, produced by astrocytes, reaches the circulatory system. We discuss the concept of S100B as an alarmin and its dual activity as an inflammatory and neurotrophic molecule. Furthermore, we emphasize the lack of data supporting the idea that S100B acts as a marker of BBB rupture, and the need to include the glymphatic system in the interpretations of serum changes of S100B. The review is also dedicated to valorizing extracerebral sources of S100B, particularly adipocytes. Furthermore, S100B per se may have direct and indirect modulating roles in brain barriers: on the tight junctions that regulate paracellular transport; on the expression of its receptor, RAGE, which is involved in transcellular protein transport; and on aquaporin-4, a key protein in the glymphatic system that is responsible for the clearance of extracellular proteins from the central nervous system. We hope that the data on S100B, discussed here, will be useful and that it will translate into further health benefits in medical practice.

Ventriculoperitoneal shunt is associated with increased cerebrospinal fluid protein level in HIV-infected cryptococcal meningitis patients

Background

The impact of ventriculoperitoneal shunt on cerebrospinal fluid (CSF) biochemical profiles in HIV-associated cryptococcal meningitis (HCM) patients remains unclear.

Methods

Twenty-nine HCM patients who underwent ventriculoperitoneal shunt (the VPS group) and 57 HCM patients who did not undergo ventriculoperitoneal shunt (the non-VPS group) were enrolled in this propensity score matching analysis. Demographic characteristics, symptoms, CSF biochemical profiles, and adverse events were compared between the two groups. The Kaplan–Meier method was used to analyze the survival rate. Univariate and multivariate logistic regression analyses were performed to identify the risk factors for increased CSF protein levels.

Results

After 24 weeks of treatment, the intracranial pressure was significantly lower in the VPS group than in the non-VPS group (mmH₂O; 155.0 [120.0–190.0] vs. 200.0 [142.5–290.0]; P = 0.025), and the rate of neuroimaging improvement was significantly higher in the VPS group (16/17 [94.1%] vs. 2/10 [20%]; P < 0.001). Furthermore, the 24-week cumulative survival rates were also significantly higher in the VPS group (96.6% vs. 83.5%, P = 0.025). Notably, the CSF protein levels were higher in the VPS group than in the non-VPS group at each examination time, and the CSF glucose was lower in the VPS group than in the non-VPS group even at the 12-week follow-up. In the multivariate analysis, we found that VPS placement was an independent risk factor for increased CSF protein (odds ratio [OR]: 27.8, 95% confidence interval [95% CI] 2.2–348.7; P = 0.010).

Conclusions

VPS decreased the intracranial pressure, improved neuroimaging radiology and reduced the 24-week mortality in HCM patients. However, VPS significantly altered the CSF profiles, which could lead to misdiagnosis of tuberculous meningitis and some of them were diagnosed with immune reconstitution inflammatory syndrome. Physicians should be aware of these changes in the CSF profiles of patients with HCM undergoing VPS.

Ventriculolumbar perfusion and inhalational anesthesia with sevoflurane in an accidental intrathecal injection of tranexamic acid: unreported treatment options

BACKGROUND

Tranexamic acid (TXA) decreases hemorrhage-related mortality in trauma patients and is increasingly being used during obstetric and orthopedic surgeries. Inadvertent intrathecal injection of TXA is a rare, potentially lethal event leading to dose-dependent cardiotoxicity and neurotoxicity. TXA enhances neuronal excitation by antagonizing inhibitory γ-aminobutyric acid type A and glycine receptors. Until now, mechanistic-based pharmacological treatments targeting multiple central nervous system receptors have been advocated for use in such cases, with no data on intrathecal TXA elimination techniques.

CASE PRESENTATION

A patient scheduled for hip surgery accidentally received 350 mg of intrathecal TXA instead of levobupivacaine. The clinical picture progressed from spinal segmental myoclonus to generalized convulsions and malignant arrhythmias. The treatment consisted of ventriculolumbar perfusion with normal saline at a rate of 50 mL/hour starting 5 hours after TXA administration and inhalational sedation with sevoflurane, in addition to drugs acting on multiple receptors at different central nervous system levels. Over 2 months the neurological status improved, although it was not complete.

CONCLUSIONS

For the first time, the feasibility and possible clinical efficacy of combined treatment with ventriculolumbar perfusion and inhalational sedation with sevoflurane were demonstrated. A referral to a neurosurgical facility is recommended in patients with acute TXA-induced neurotoxicity and cardiotoxicity.

[Clinical value of serum neuroglobin in evaluating hypoglycemic brain injury in neonates]

OBJECTIVE

To study the clinical value of serum neuroglobin in evaluating hypoglycemic brain injury in neonates.

METHODS

A total of 100 neonates with hypoglycemia were enrolled as subjects. According to amplitude-integrated EEG (aEEG) findings and/or clinical manifestations, they were divided into symptomatic hypoglycemic brain injury group (n=22), asymptomatic hypoglycemic brain injury group (n=37) and hypoglycemic non-brain injury group (n=41). The three groups were compared in terms of blood glucose, duration of hypoglycemia, levels of neuroglobin and neuron-specific enolase (NSE), and modified aEEG score. The correlation of neuroglobin with NSE and modified aEEG score was analyzed. The receiver operating characteristic (ROC) curve was plotted.

RESULTS

Compared with the asymptomatic hypoglycemic brain injury and hypoglycemic non-brain injury groups, the symptomatic hypoglycemic brain injury group had significantly lower blood glucose and modified aEEG score, significantly higher neuroglobin and NSE levels, and a significantly longer duration of hypoglycemia (P<0.05). Compared with the hypoglycemic non-brain injury group, the asymptomatic hypoglycemic brain injury group had significantly lower blood glucose and modified aEEG score, significantly higher neuroglobin and NSE levels, and a significantly longer duration of hypoglycemia (P<0.05). Neuroglobin was positively correlated with NSE and duration of hypoglycemia (r=0.922 and 0.929 respectively; P<0.05) and negatively correlated with blood glucose and modified aEEG score (r=-0.849 and -0.968 respectively; P<0.05). The areas under the ROC curve of neuroglobin, NSE and modified aEEG score were 0.894, 0.890 and 0.941 respectively, and neuroglobin had a sensitivity of 80.8% and a specificity of 95.8% at the optimal cut-off value of 108 mg/L.

CONCLUSIONS

Like NSE and modified aEEG score, serum neuroglobin can also be used as a specific indicator for the assessment of brain injury in neonates with hypoglycemia and has a certain value in clinical practice.

Clinical significance of changes in IL-6, CRP and S100in serum and NO in cerebrospinal fluid insubarachnoid hemorrhage and prognosis

Clinical significance of changes in interleukin-6 (IL-6), C-reactive protein (CRP) and S100 in serum and NO was investigated in cerebrospinal fluid (CSF) in subarachnoid hemorrhage (SAH) and its prognosis. A total of 43 SAH patients and 23 healthy subjects were selected and divided into cerebral vasospasm (CVS) group and non-CVS group, and favorable prognosis group and unfavorable prognosis group according to Hunt-Hess grade. The levels of IL-6, CRP, S100 and NO in CSF were detected, respectively, followed by statistical analysis of correlation. The higher the Hunt grade was, the higher the factor expression was; the expression levels of IL-6, CRP, S100 and NO in CSF were gradually increased in CVS group and unfavorable prognosis group, and the differences were significant compared with those in the control group. There was a positive correlation between the expression levels of each of the two factors among IL-6, CRP, S100 and NO in CSF, and the differences were statistically significant (P<0.05). The expression levels of IL-6, CRP, S100 and NO in CSF in SAH patients are significantly increased, showing positive correlations and participating in the occurrence and development of SAH, which provide new directions for the early clinical diagnosis of SAH.

Metabolic syndrome and its components with neuron-specific enolase: a cross-sectional study in large health check-up population in China

OBJECTIVE

This study was aimed at investigating the relationship between neuron-specific enolase (NSE) and components of metabolic syndrome (MS).

DESIGN

Cross-sectional study.

SETTING

Chinese health check-up population.

PARTICIPANTS

40 684 health check-up people were enrolled in this study from year 2014 to 2016.

MAIN OUTCOME MEASURES

OR and coefficient for MS.

RESULTS

The percentage of abnormal NSE and MS was 26.85% and 8.85%, respectively. There were significant differences in sex, body mass index, drinking habit, triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), blood pressure and MS between low-NSE and high-NSE groups. In logistic regression analysis, elevated NSE was present in MS, higher body mass index, hypertriglyceridaemia, hypertension and low-HDL groups. Stepwise linear analysis showed a negative correlation between NSE and fasting blood glucose (FBG) (<6.0 mmol/L), and a positive correlation between NSE and TGs (<20 mmol/L), systolic blood pressure (75-200 mm Hg), HDL-C (0.75-2.50 mmol/L), diastolic blood pressure (<70 mm Hg) and FBG (6.00-20.00 mmol/L). Furthermore, MS was positively correlated with NSE within the range of 2.00-7.50 ng/mL, but had a negative correlation with NSE within the range of 7.50-23.00 ng/mL.

CONCLUSION

There are associations between NSE with MS and its components. The result suggests that NSE may be a potential predictor of MS. Further research could be conducted in discussing the potential mechanism involved.

Brain Monitoring in Critically Neurologically Impaired Patients

Assessment of neurologic injury and the evolution of severe neurologic injury is limited in comatose or critically ill patients that lack a reliable neurologic examination. For common yet severe pathologies such as the comatose state after cardiac arrest, aneurysmal subarachnoid hemorrhage (aSAH), and severe traumatic brain injury (TBI), critical medical decisions are made on the basis of the neurologic injury. Decisions regarding active intensive care management, need for neurosurgical intervention, and withdrawal of care, depend on a reliable, high-quality assessment of the true state of neurologic injury, and have traditionally relied on limited assessments such as intracranial pressure monitoring and electroencephalogram. However, even within TBI there exists a spectrum of disease that is likely not captured by such limited monitoring and thus a more directed effort towards obtaining a more robust biophysical signature of the individual patient must be undertaken. In this review, multimodal monitoring including the most promising serum markers of neuronal injury, cerebral microdialysis, brain tissue oxygenation, and pressure reactivity index to access brain microenvironment will be discussed with their utility among specific pathologies that may help determine a more complete picture of the neurologic injury state for active intensive care management and long-term outcomes. Goal-directed therapy guided by a multi-modality approach appears to be superior to standard intracranial pressure (ICP) guided therapy and should be explored further across multiple pathologies. Future directions including the application of optogenetics to evaluate brain injury and recovery and even as an adjunct monitoring modality will also be discussed.

Biomarkers of Traumatic Brain Injury: Temporal Changes in Body Fluids

Traumatic brain injuries (TBIs) are caused by a hit to the head or a sudden acceleration/deceleration movement of the head. Mild TBIs (mTBIs) and concussions are difficult to diagnose. Imaging techniques often fail to find alterations in the brain, and computed tomography exposes the patient to radiation. Brain-specific biomolecules that are released upon cellular damage serve as another means of diagnosing TBI and assessing the severity of injury. These biomarkers can be detected from samples of body fluids using laboratory tests. Dozens of TBI biomarkers have been studied, and research related to them is increasing. We reviewed the recent literature and selected 12 biomarkers relevant to rapid and accurate diagnostics of TBI for further evaluation. The objective was especially to get a view of the temporal profiles of the biomarkers’ rise and decline after a TBI event. Most biomarkers are rapidly elevated after injury, and they serve as diagnostics tools for some days. Some biomarkers are elevated for months after injury, although the literature on long-term biomarkers is scarce. Clinical utilization of TBI biomarkers is still at a very early phase despite years of active research.

The Relationship Between Serum Neuron-Specific Enolase Levels and Severity of Bleeding and Functional Outcomes in Patients With Nontraumatic Subarachnoid Hemorrhage

BACKGROUND

The value of neuron-specific enolase (NSE) in predicting clinical outcomes has been investigated in a variety of neurological disorders.

OBJECTIVE

To investigate the associations of serum NSE with severity of bleeding and functional outcomes in patients with subarachnoid hemorrhage (SAH).

METHODS

We retrospectively reviewed the records of patients with SAH from June 2008 to June 2012. The severity of SAH bleeding at admission was measured radiographically with the Fisher scale and clinically with the Glasgow Coma Scale, Hunt and Hess grade, and World Federation of Neurologic Surgeons scale. Outcomes were assessed with the modified Rankin Scale at discharge.

RESULTS

We identified 309 patients with nontraumatic SAH, and 71 had NSE testing. Median age was 54 years (range, 23-87 years), and 44% were male. In multivariable analysis, increased NSE was associated with a poorer Hunt and Hess grade (P = .003), World Federation of Neurologic Surgeons scale score (P < .001), and Glasgow Coma Scale score (P = .003) and worse outcomes (modified Rankin Scale at discharge; P = .001). There was no significant association between NSE level and Fisher grade (P = .81) in multivariable analysis.

CONCLUSION

We found a significant association between higher NSE levels and poorer clinical presentations and worse outcomes. Although it is still early for any relevant clinical conclusions, our results suggest that NSE holds promise as a tool for screening patients at increased risk of poor outcomes after SAH.

Microglial activation induced by the alarmin S100B is regulated by poly(ADP-ribose) polymerase-1

Brain injury resulting from stroke or trauma can be exacerbated by the release of proinflammatory cytokines, proteases, and reactive oxygen species by activated microglia. The microglial activation resulting from brain injury is mediated in part by alarmins, which are signaling molecules released from damaged cells. The nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1) has been shown to regulate microglial activation after brain injury, and here we show that signaling effects of the alarmin S100B are regulated by PARP-1. S100B is a protein localized predominantly to astrocytes. Exogenous S100B added to primary microglial cultures induced a rapid change in microglial morphology, upregulation of IL-1β, TNFα, and iNOS gene expression, and release of matrix metalloproteinase 9 and nitric oxide. Most, though not all of these effects were attenuated in PARP-1(-/-) microglia and in wild-type microglia treated with the PARP inhibitor, veliparib. Microglial activation and gene expression changes induced by S100B injected directly into brain were likewise attenuated by PARP-1 inhibition. The anti-inflammatory effects of PARP-1 inhibitors in acutely injured brain may thus be mediated in part through effects on S100B signaling pathways. GLIA 2016;64:1869-1878.

Early CSF and Serum S100B Concentrations for Outcome Prediction in Traumatic Brain Injury and Subarachnoid Hemorrhage

OBJECTIVES

S100B has been proposed as a putative biochemical marker in determining the extent of brain injury and corresponding prognosis in neurotrauma. The aim of this study was to evaluate the prognostic value of S100B early concentrations in serum and cerebrospinal fluid (CSF) in traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH), to determine prognostically relevant threshold values and to evaluate fluctuation following EVD placement.

PATIENTS AND METHODS

In 102 patients (45 SAH and 57 TBI) under intensive care unit (ICU) treated between January 2011 and December 2012 with external ventricular drain (EVD) S100B measurements were performed simultaneously in serum and CSF during the first 5 days and before and after EVD exchange. Glasgow coma scale (GCS) was assessed on admission and Glasgow outcome scale (GOS) 6 months later.

RESULTS

Peak S100B levels in CSF and serum were measured on the first day after admission and concentrations decreased during the ensuing days post injury gradually. CSF and serum S100B concentrations in TBI patients were significantly higher than in SAH (p<0.005). Both in TBI and SAH patients S100B concentrations in CSF and serum were significantly higher in patients with an unfavorable outcome (GOS 1-3) in comparison to patients with a good outcome (GOS 4-5). Correlation of S100B concentrations in serum and GOS score at 6 months was significant both in TBI and SAH (p<0.05). Serum S100B concentrations >0.7μg/l correlated with 100% mortality. Correlation between S100B in CSF and GOS was significant in SAH (p<0.05), whereas it was not significant in TBI. After EVD exchange (n=53) we found a significant increase of S100B concentration in CSF (p<0.005).

CONCLUSION

Initial S100B levels have a limited prognostic value in neurotrauma with CSF concentrations being highly sensitive to smallest influences like EVD placement. However, high initial S100B levels of >0.7μg/dl in serum are associated with 100% mortality, which might help to guide therapy strategies in severe neurotrauma.

Elevated Serum Levels of NSE and S-100β Correlate with Increased Risk of Acute Cerebral Infarction in Asian Populations

BACKGROUND

We investigated the clinical value of serum levels of neuron-specific enolase (NSE) and human soluble protein-100β (S-100β) in acute cerebral infarction (ACI) patients.

MATERIAL AND METHODS

A literature search of electronic databases identified relevant case-control studies that examined the correlations between NSE and S-100β serum levels, and ACI. The retrieved studies were screened based on our strict inclusion and exclusion criteria, and high-quality studies were subsequently selected for meta-analysis. STATA software (Version 12.0, Stata Corporation, College Station, TX, USA) was utilized for statistical analysis.

RESULTS

A total of 13 case-control studies, containing 911 ACI patients and 686 healthy controls, were enrolled in this meta-analysis. The results of the meta-analysis showed that serum levels of NSE and S-100β in ACI patients were significantly higher than the control group. Subgroup analysis based on ethnicity revealed that the serum levels of NSE and S-100β in ACI patients were significantly higher than the control group in Asian population. In Caucasian population, the serum levels of NSE in case group was significantly higher than the control group, but no significant differences in serum levels of S-100β were observed between ACI patients and the control group.

CONCLUSIONS

Based on our results, we conclude that serum levels of NSE and S-100β strongly correlate with ACI in Asian population, and may be important clinical markers for diagnosis and treatment of ACI.

Proteomics: in pursuit of effective traumatic brain injury therapeutics

Effective traumatic brain injury (TBI) therapeutics remains stubbornly elusive. Efforts in the field have been challenged by the heterogeneity of clinical TBI, with greater complexity among underlying molecular phenotypes than initially conceived. Future research must confront the multitude of factors comprising this heterogeneity, representing a big data challenge befitting the coming informatics age. Proteomics is poised to serve a central role in prescriptive therapeutic development because it offers an efficient endpoint within which to assess post-TBI biochemistry. We examine rationale for multifactor TBI proteomic studies and the particular importance of temporal profiling in defining biochemical sequences and guiding therapeutic development. Finally, we offer perspective on repurposing biofluid proteomics to develop theragnostic assays with which to prescribe, monitor and assess pharmaceutics for improved translation and outcome for patients with TBI.

Neuroprotein dynamics in the cerebrospinal fluid: intraindividual concomitant ventricular and lumbar measurements

OBJECTIVE

The measurement of neuromarker/neuroproteins in the cerebrospinal fluid (CSF) is gaining increased popularity. However, insufficient information is available on the rostrocaudal distribution of neuroproteins in the CSF to guarantee an appropriate interpretation of ventricular versus lumbar concentrations.

METHODS

In 10 patients treated with both an external ventricular and a lumbar CSF drain, we collected concomitant CSF samples. We measured CSF concentrations of the glial S100B protein, the neuron-specific enolase (Cobas e411®; Roche Diagnostics), the leptomeningeal β-trace protein (BN Pro Spec®; Dade Behring/Siemens), and the blood-derived albumin (Immage; Beckman Coulter). Statistical analysis was performed with a paired Wilcoxon signed ranks test.

RESULTS

In patients with a free CSF circulation without any recent neurosurgical procedure, S100B and neuron-specific enolase concentrations did not differ between the ventricular and lumbar CSF while β-trace and albumin levels were significantly higher in the lumbar than in the ventricular CSF (p=0.008 and p=0.005). Following posterior fossa tumor surgery, all proteins accumulate in the lumbar CSF.

CONCLUSION

For brain-derived proteins, we could not confirm a rostrocaudal CSF gradient while lepto-meningeal and blood-derived proteins accumulate in the lumbar CSF. We conclude that for the interpretation of protein CSF concentrations, the source of the sample is of crucial importance.