Nerve tissue protein S-100 and neurone-specific enolase concentrations in cerebrospinal fluid and blood during carotid endarterectomy

The role of stump pressure and cerebral oximetry in predicting ischaemic brain damage during carotid endarterectomy

Objective is to compare the predictive value of stump pressure (SP) and cerebral oximetry (rSO2) levels in the evaluation of ischaemic injury of the cerebrum during clamping of the carotid artery (CCA) without temporary shunt (TS). Methods We included 84 patients with an asymptomatic stenosis (>70%) of the internal carotid artery (ICA) who underwent carotid endarterectomy (CEA) under GA. Cerebral ischaemic tolerance (CIT) was determined on the basis of SP, rSO2 and ∆rSO2 (↓rSO2 from baseline) during CCA. The levels of S100 protein (S100) and neuron-specific enolase (NSE) were measured on each stage of the study. MRI was performed for all patients. Results There were no perioperative strokes and myocardial infarctions during the study. Temporary shutdown of blood flow in CAs during CEA is accompanied by a significant elevation of S100, NSE concentration with their subsequent restoration (three days after surgery). ROC analysis showed that none of the methods for CIT assessment (SP, rSO2 and ∆rSO2) was a valuable predictor of cerebral damage during CEA. Conclusion SP with a threshold value of ≤40 mmHg has an average quality of prediction (AUC = 63). ∆rSO2 of ≥20% and a threshold value of rSO2 ≤ 40% have an unsatisfactory quality of prediction (AUC < 60).

Alterations in pain responsiveness and serum biomarkers in juvenile myoclonic epilepsy: an age- and gender-matched controlled pilot study

Introduction: Serum levels of several biomarkers along with sensory responsiveness were investigated in juvenile myoclonic epilepsy patients in comparison with healthy controls. Methods: Ten epileptic patients (36.1 ± 3.4 years) and ten gender- and age-matched healthy controls were recruited. Mechanical sensitivity, cold pressor tolerance and serum levels of BDNF, CGRP, PGE2, S100B and TNF-α were investigated. Results: Mechanical sensitivity to pinprick was lower in patients (p < 0.05) while cold pain tolerance threshold was higher. Serum level of BDNF was higher in patients compared with controls (p < 0.01). The same pattern was evident for CGRP (p < 0.05). Serum level of PGE2 was lower in patients (p < 0.01). Conclusion: Juvenile myoclonic epilepsy patients had an altered serum biomarker pattern and sensory perception in comparison with controls.

Subclinical neurocognitive dysfunction after carotid endarterectomy-the impact of shunting

BACKGROUND

Subclinical neurocognitive deficit after carotid endarterectomy (CEA) has been reported in 25% of patients. The influence of the type of anesthesia and shunting on early postoperative neurocognitive function remains unclear. Therefore, we analyzed the cognitive function after CEA using a battery of psychometric tests before surgery and on the first postoperative day.

METHODS

Twenty nine patients under regional and 28 under general anesthesia were included in the study. Regional anesthesia was administered inducing a superficial cervical block, and the general anesthesia was induced using a standardized manner. Then cognitive function was tested using a battery of psychometric tests before and 24 hours after surgery. S 100 beta was determined at the same time points.

RESULTS

A statistical difference was found between the results of the testing before and after CEA: decline in digit symbol test (9%), perceptual speed (6%), and spatial working memory (44%) and improvement in verbal fluency (6%) and attention (5%). The only intraoperative factor that correlated with the cognitive dysfunction was shunt insertion; patients with a shunt had a lower perceptual speed (P=0.005) and worse spatial working memory (P=0.004). No correlation was found between the type of anesthesia or S 100 beta level and any psychometric test, but these results might be influenced by the small sample size in our study.

CONCLUSIONS

Shunt insertion was the only parameter correlated with cognitive decline on the first day after CEA. Regional anesthesia might offer indirect benefit because of a reduced need of shunting in wakeful patients. Larger studies are required to clarify the role of shunting and type of anesthesia in early neurocognitive deficit after CEA and its impact on the quality of life.

S-100B Release during Carotid Endarterectomy under Local Anesthesia

The neuronal protein S-100B has been found to be an indicator of cellular brain damage. The aim of the study was to evaluate whether cross-clamping of the carotid artery for carotid endarterectomy (CEA) under local anesthesia is associated with the same S-100B release pattern as during general anesthesia, where an increase in S-100B concentration in the jugular vein blood of 120% has been reported. In 45 consecutive patients undergoing CEA under local anesthesia, serum S-100B samples were drawn before surgery (T1), before carotid cross-clamping (T2), before cerebral reperfusion (T3), after reperfusion but before the end of surgery (T4), and 6 hr postoperatively (T5). At T1 and T5, blood samples were drawn only from the radial artery. Intraoperatively (T2-T4), samples were collected from the internal jugular vein additionally. S-100B levels were determined using an immunoluminometric assay (LIAISON) Sangtec 100; Sangtec, Bromma, Sweden). In eight patients, it was necessary to insert an intraluminal shunt because of signs of cerebral ischemia. In the remaining 37 patients, median carotid clamping time was 40 min. There were no neurological complications. There were no differences in baseline S-100B levels regarding gender and symptomatology. Median baseline (T1) and postoperative (T5) S-100B levels were identical (0.077 microg/L). All blood samples from the jugular vein showed significantly higher median S-100B levels than the corresponding arterial blood samples. Only slight increases of 13% and 18% were found during cross-clamping (T3) compared to the first intraoperative measurement (T2) in the venous and arterial samples, respectively, which was followed by decreases of 5% and 18%, respectively (T3-T4). S-100B release did not differ at any time point between patients who needed and patients who did not need a shunt, in either the arterial or the venous blood samples. During uncomplicated CEA under local anesthesia, there is no relevant increase of S-100B. These results are different from those reported when CEA is done under general anesthesia.

Neuropsychological consequences of endarterectomy and endovascular angioplasty with stent placement for treatment of symptomatic carotid stenosis

BACKGROUND AND PURPOSE

Previous studies compared carotid endarterectomy (CEA) and carotid artery stent placement (CAS) for treatment of symptomatic carotid artery stenosis. Whereas most previous studies showed both treatment modalities to be associated with a comparable risk of periprocedural cerebrovascular complications, these previous studies have shown significantly more microemboli and significantly more lesions in diffusion-weighted MR imaging after CAS compared to CEA. The clinical relevance of these differences remains unknown. We therefore compared the neuropsychological consequences of CAS and CEA and additionally measured the S100beta protein, a marker of cerebral damage.

METHODS

A total of 48 patients with symptomatic carotid artery stenosis greater than 70 % (according to ECST criteria) were enrolled and 45 patients participated in the follow-up. The patients were randomly assigned for CEA (24 patients) or CAS (21 patients). S100beta protein values were evaluated 2 hours before the procedure, as well as one and two hours thereafter. Patients were assessed before treatment, and again 6 and 30 days after treatment using a comprehensive neuropsychological test battery.

RESULTS

Patients of the CAS and the CEA groups did not significantly differ in terms of age, gender, education, degree of carotid artery stenosis, cerebrovascular symptoms and vascular risk factors. Following previously used criteria, a cognitive change in patients was assumed to have occurred when there was a decline of more than one standard deviation in two or more tests assessing various cognitive domains. Six days and 30 days after the treatment both groups showed a comparable number of patients with cognitive changes compared to baseline. There were no significant differences in S100beta protein values.

CONCLUSION

These results provide some reassurance that CAS is not associated with greater cognitive deterioration than CEA is.

Serum S-100B protein levels during and after successful carotid artery stenting or carotid endarterectomy

PURPOSE

To characterize the course of S-100B serum levels, a reliable marker for cellular brain damage, in patients undergoing carotid artery stenting (CAS) or endarterectomy (CEA) for carotid artery stenosis compared to control groups undergoing hemithyroidectomy (HT) or coronary angiography (CA).

METHODS

Forty-six consecutive patients scheduled for revascularization of internal carotid artery (ICA) stenosis were included in the study. Fourteen patients (11 men; median age 70 years, interquartile range [IQR] 63-74) were selected for treatment with CAS, while CEA was performed in 31 patients (24 men; median age 68 years, IQR 54-78) during the same time period. Fourteen consecutive patients (8 men; median age 60 years, IQR 48-70) undergoing CA for suspected coronary heart disease and 14 patients (10 women; median age 36 years, IQR 26-54) undergoing HT for a single thyroid nodule served as controls.

RESULTS

All procedures were completed successfully. During ICA clamping in CEA patients without postoperative neurological deficits, median S-100B serum levels transiently increased from 0.04 to 0.26 ng/mL (p<0.01) and returned to baseline levels after declamping. Median S-100B serum levels of CAS patients without neurological impairment remained at baseline values. No increase in S-100B levels occurred in either control group. Three CEA patients who suffered from neurological deficits (1 transient ischemic attack and 1 major stroke) showed sustained elevation of S-100B serum levels 6 hours after extubation.

CONCLUSION

In patients without neurological complications, CEA but not CAS was associated with a transient increase in the S-100B serum levels. Results indicate that the increase in S-100B does not originate from extracerebral sources, but rather appears to represent an impairment of the blood-brain barrier integrity or subtle brain cell damage probably due to hypoperfusion during clamping. Sustained elevation of S-100B serum levels corresponded to the development of postoperative neurological deficits.

Rapid measurement of S-100B serum protein levels by Elecsys S100 immunoassay in patients undergoing carotid artery stenting or endarterectomy

OBJECTIVES

This study was designed to apply the rapid Elecsys S100 immunoassay for real-time measurement of S100 protein serum levels indicating acute brain damage in patients undergoing carotid artery stenting (CAS) or endarterectomy (CEA).

DESIGN AND METHODS

Data of 14 CAS patients were compared to those of 43 CEA and 14 control patients undergoing coronary angiography (CA). S100 serum levels were measured by the full-automatic Elecsys S100 immunoassay and compared to those obtained by the well-established LIA-mat S100 system.

RESULTS

In contrast to CAS and CA patients, median S100 serum levels of CEA patients significantly increased to 0.24 ng/mL before declamping, but subsequently returned to baseline. Three CEA patients with neurological deficits showed sustained elevated S100 levels 6 h after extubation. Absolute S100 values were not significantly different between the two methods. Bland-Altman plot analyses displayed a good agreement, mostly indicating slightly smaller values applying the Elecsys S100 system.

CONCLUSIONS

The Elecsys S100 system appears to be suitable for rapid real-time detection of neurological deficits in patients undergoing CAS and CEA. Persistent elevations of Elecsys S100 levels during CEA were associated with prolonged neurological disorders, whereas transient increases seem to represent impaired blood-brain barrier integrity without neurological deficits.

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.

Release of neuron-specific enolase and S100 after implantation of cardioverters/defibrillators

OBJECTIVE

Repeated induction of ventricular fibrillation with ensuing alterations in electroencephalogram and jugular venous oxygen saturation is common practice during insertion of transvenous implantable cardioverters/defibrillators. We investigated whether these functional changes are also associated with cerebral injury.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

We studied 45 patients undergoing implantable cardioverter/defibrillator insertion. Eleven patients with cardiac pacemaker implantation, which was performed in the same manner yet without the necessity to induce ventricular fibrillation, served as controls.

MEASUREMENTS AND MAIN RESULTS

Serum neuron-specific enolase and S100 were determined before, immediately postoperatively, and 2 hrs postoperatively. In a randomly composed subgroup, neuron-specific enolase was also determined 6 and 24 hrs after surgery. Implantable cardioverter/defibrillator patients only showed an increase of both markers postoperatively. Median neuron-specific enolase values climbed from a preoperative 9.9 to 12.3 and 14.4 microg/L at 2 and 24 hrs after surgery, respectively. This increase was associated with the number of shocks and the cumulative time in circulatory arrest. The highest median S100 level (0.075 microg/L) was reached 2 hrs after the procedure. Neuron-specific enolase and S100 were extremely elevated (13.7 and 0.970 microg/L, respectively) in one patient after an extended episode of ventricular fibrillation. Plasma hemoglobin levels were in the normal range in implantable cardioverter/defibrillator patients throughout the observation period.

CONCLUSIONS

Apparently, even brief successive periods of global cerebral ischemia cause neuronal damage without obvious severe neurologic deficits. However, they may be related to subtle postoperative neurologic or cognitive dysfunctions that a number of implantable cardioverter/defibrillator patients exhibit after implantation.

S100B in brain damage and neurodegeneration

S100B is a calcium-binding peptide produced mainly by astrocytes that exert paracrine and autocrine effects on neurons and glia. Some knowledge has been acquired from in vitro and in vivo animal experiments to understand S100B's roles in cellular energy metabolism, cytoskeleton modification, cell proliferation, and differentiation. Also, insights have been gained regarding the interaction between S100B and the cerebral immune system, and the regulation of S100B activity through serotonergic transmission. Secreted glial S100B exerts trophic or toxic effects depending on its concentration. At nanomolar concentrations, S100B stimulates neurite outgrowth and enhances survival of neurons during development. In contrast, micromolar levels of extracellular S100B in vitro stimulate the expression of proinflammatory cytokines and induce apoptosis. In animal studies, changes in the cerebral concentration of S100B cause behavioral disturbances and cognitive deficits. In humans, increased S100B has been detected with various clinical conditions. Brain trauma and ischemia is associated with increased S100B concentrations, probably due to the destruction of astrocytes. In neurodegenerative, inflammatory and psychiatric diseases, increased S100B levels may be caused by secreted S100B or release from damaged astrocytes. This review summarizes published findings on S100B regarding human brain damage and neurodegeneration. Findings from in vitro and in vivo animal experiments relevant for human neurodegenerative diseases and brain damage are reviewed together with the results of studies on traumatic, ischemic, and inflammatory brain damage as well as neurodegenerative and psychiatric disorders. Methodological problems are discussed and perspectives for future research are outlined.