Correlative study between neuron-specific enolase and blood sugar level in ischemic stroke patients

Multifunctional roles of γ-enolase in the central nervous system: more than a neuronal marker

Enolase, a multifunctional protein with diverse isoforms, has generally been recognized for its primary roles in glycolysis and gluconeogenesis. The shift in isoform expression from α-enolase to neuron-specific γ-enolase extends beyond its enzymatic role. Enolase is essential for neuronal survival, differentiation, and the maturation of neurons and glial cells in the central nervous system. Neuron-specific γ-enolase is a critical biomarker for neurodegenerative pathologies and neurological conditions, not only indicating disease but also participating in nerve cell formation and neuroprotection and exhibiting neurotrophic-like properties. These properties are precisely regulated by cysteine peptidase cathepsin X and scaffold protein γ1-syntrophin. Our findings suggest that γ-enolase, specifically its C-terminal part, may offer neuroprotective benefits against neurotoxicity seen in Alzheimer's and Parkinson's disease. Furthermore, although the therapeutic potential of γ-enolase seems promising, the effectiveness of enolase inhibitors is under debate. This paper reviews the research on the roles of γ-enolase in the central nervous system, especially in pathophysiological events and the regulation of neurodegenerative diseases.

Refraining from Packed Red Blood Cells in Cardiopulmonary Bypass Priming as a Method of Neuroprotection in Pediatric Cardiac Surgery

Congenital heart defect (CHD) surgeries are performed with cardiopulmonary bypass (CPB) and are complicated by several factors that affect the child's brain. However, to date, the number of studies on brain protection in cardiac surgery remains small. The aim of this study was to assess the impact of refraining from using packed red blood cells (PRBCs) in priming solutions in children with congenital defects (CHDs) who require surgical interventions using CPB to prevent brain injury in the postoperative period.

MATERIAL AND METHODS

This study included 40 children, and the mean age was 14 (12-22.5) months and the mean weight was 8.8 (7.25-11) kg. All patients underwent CHD closure using CPB. The patients were divided into two groups depending on the use of PRBCs in the priming solution. Brain injury was assessed using three specific blood serum markers, namely S100 calcium-binding protein β (S100β), neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) before surgery, after the completion of CPB and 16 h after surgery (first, second and third control points). Markers of systemic inflammatory response were also analyzed, including interleukin-1, -6, -10 and tumor necrosis factor alpha (TNF-α). A clinical assessment of brain injury was carried out using a valid, rapid, observational tool for screening delirium in children of this age group, i.e., "Cornell Assessment of Pediatric Delirium".

RESULTS

Factors of the intra- and postoperative period were analyzed, such as hemoglobin levels, oxygen delivery (cerebral tissue oxygenation, blood lactate level and venous oxygen saturation) and indicators of organ dysfunction (creatinine, urea, bilirubin levels, duration of CPB and length of stay in the ICU). Following the procedure, there were no significant differences between the groups and all indicators were within the reference values, thus demonstrating the safety of CHD closure without transfusion. Moreover, the highest level of specific markers of brain injury were noted immediately after the completion of CPB in both groups. The concentration of all three markers was significantly higher in the group with transfusion after the completion of CPB. Moreover, GFAP levels were higher in the transfusion group and 16 h after surgery.

CONCLUSIONS

The results of the study show the safety and effectiveness of brain injury prevention strategies that consist of not conducting PRBC transfusion.

The Relationship Between Neuron-Specific Enolase and Clinical Outcomes in Patients Undergoing Mechanical Thrombectomy

Purpose

Neuron-specific enolase (NSE) is considered a biomarker for the severity of nervous system diseases. We sought to explore whether serum NSE concentration in ischemic stroke patients undergoing mechanical thrombectomy (MT) is related to 3-month functional outcome and symptomatic intracranial hemorrhage (sICH).

Patients and Methods

We retrospectively collected the data of acute ischemic stroke patients with anterior circulation infarction receiving MT within 6 h in our stroke center. Favorable outcome and poor outcome at 3 months were defined as modified Rankin Scale (mRS) score 0-2 and 3-6, respectively. sICH was defined according to the Heidelberg bleeding classification. We used multivariate logistic regression model and receiver operating characteristic curves to investigate the correlation between NSE and clinical outcomes.

Results

Among the 426 patients enrolled, 40 (9.4%) patients developed sICH. Three-month favorable outcome in 160 (37.6%) and poor outcome in 266 (62.4%) patients were observed. Serum NSE levels was significantly correlated with 3-month mRS score (R = 0.473, P < 0.001). A cutoff value of 15.29 and 23.12 ng/mL for serum NSE was detected in discriminating 3-month poor outcome (area under the curve, 0.724) and sICH (area under the curve, 0.716), respectively. Multivariate analysis showed that high serum NSE levels were independently associated with 3-month poor outcome (odds ratio [OR] 5.049, 95% confidence interval [CI] 2.933-8.689, P<0.001) and sICH (OR 5.111, 95% CI 2.210-11.820, P < 0.001).

Conclusion

Our study demonstrated that high serum NSE levels after receiving MT were independently associated with 3-month poor outcome and sICH in acute ischemic stroke patients. Serum NSE levels could be a good predictor of clinical outcomes for patients receiving MT.

Relationship between Neuron-specific Enolase Serum Levels with Lesion Volume and Clinical Outcome in Acute Stroke Patients

BACKGROUND: Neuron-specific enolase (NSE) is released in the cerebrospinal fluid and bloodstream in response to brain damage. Serum NSE levels can be used as a marker of brain nerve cells either in ischemic or hemorrhagic stroke, associated with lesion volume and functional outcome. AIM: The aim of the study was to evaluate the correlation between NSE serum level with lesion volume and functional outcome in acute stroke patients. METHODS: A cross-sectional study was conducted on 29 patients with ischemic stroke and 29 hemorrhagic strokes admitted to Haji Adam General Hospital. All the subjects were assessed with the National Institute of Health Stroke Scale (NIHSS) score, modified Rankin scale (mRS), and assessment of lesion volume. RESULTS: Subjects consist of 27 male (46.4%) and 31 female (53.4%), with mean age of 61.67 ± 12.26 years. The mean serum NSE levels in stroke patients were 19.79 ± 8.88 ng/ml and lesion volume was 25.09 ± 24.52 ml. There was a significant positive correlation of increase in serum NSE levels with infarct volume (r = 0.863 and p < 0.001) and hemorrhagic volume (r = 0.644 and p < 0.001) and clinical outcome assessed by NIHSS score (r = 0.761 and p < 0.001) and mRS score (r = 0.762 and p < 0.001) in ischemic stroke and NIHSS score (r = 0.525 and p = 0.003), and mRS score (r = 0.468 and p = 0.010) in hemorrhagic stroke. CONCLUSION: High NSE serum levels in the acute phase were associated with lesion volume and poor outcomes in stroke patients.

[Interaction between glycogen synthase kinase-3β and endoplasmic reticulum stress is involved in high glucose-induced injury in human umbilical vein endothelial cells]

OBJECTIVE

To explore the role of the interaction between glycogen synthase kinase-3β (GSK-3β) and endoplasmic reticulum stress (ERS) in the high glucose (HG)-induced injury in human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs treated with 40 mmol/L glucose for 24 h were examined for expression levels of GSK-3β, GRP78, CHOP and cleaved caspase-3 protein using Western blotting. The cell viability was examined using CCK-8 assay and cell apoptosis was detected with Hoechst 33258 nuclear staining and photofluorography. The intracellular level of reactive oxygen species (ROS) was measured with dichlorfluoresein staining and photofluorography. Mitochondrial membrane potential (MMP) was tested by rhodamine 123 (Rh123) staining and photofluorography.

RESULTS

Treatment of HUVECs with 40 µmol/L glucose for 3-24 h activated GSK-3β in a time-dependent manner, leading to significantly down-regulated expression of phosphorylated (p)-GSK-3β (P<0.05). HG exposure of the cells for 1-24 h induced ERS, evidenced by time-dependently up-regulated expression of GRP78 and CHOP (P<0.05). LiCl, an inhibitor of GSK-3β, attenuated HG-induced ERS and significantly lowered the expression levels of GRP78 and CHOP (P<0.01). 4-PBA, an inhibitor of ERS, obviously ameliorated the activation of GSK-3β by HG as shown by the increase in p-GSK-3β expression level (P<0.01). HG exposure for 24 h induced obvious injuries in HUVECs, which exhibited decreased cell viability, increased cell apoptosis, increased expression of cleaved caspase-3 and ROS generation, and loss of MMP. Pretreatment of the cells with LiCl or 4-PBA for 60 min before HG exposure significantly lessened the cell injuries (P<0.01).

CONCLUSION

Interactions between GSK-3β and ERS occur in HUVECs exposed to HG and participate in HG-induced cell injuries.

Prediction of Outcome in Diabetic Acute Ischemic Stroke Patients: A Hospital-Based Pilot Study Report

BACKGROUND

Demographic and clinical characteristics are known to influence the outcome in acute ischemic stroke (AIS) patients.

PURPOSE

This study is aimed at evaluating short- and long-term outcomes in diabetic AIS patients. In addition, the study also evaluates the impact of diabetes on the performance of indigenously reported biomarker, inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) and known biomarkers, neuron-specific enolase (NSE) and glial-derived S-100 beta beta protein (S-100ββ).

METHODS

This study was performed on 29 diabetes and 75 non-diabetes AIS patients. Outcome of AIS patients was analyzed by using modified Rankin scale at discharge, then at 12 and 18 months after discharge. Based on the obtained scores, patients were classified as improved group (scales 1-3) and dependent/expired group (scales 3-6). Blood samples were collected during admission and at discharge/expired time. Levels of NSE, S100ββ, and ITIH4 were analyzed in all samples.

RESULTS

On discharge, frequencies of dependent/expired outcome were 4/29 (14%) and 19/75 (17%) in diabetic and non-diabetic AIS patients. However, follow-up outcome at 12 and 18 months showed higher dependent/expired cases of 43 and 41% among diabetic AIS patients compared to 27 and 21% in non-diabetic patients. Multivariate analysis revealed that diabetes is an independent risk factor for dependent/expired outcome in AIS patients (OR 0.484 (at discharge); 1.307 (at 12 months) and 1.675 (at 18 months)). NSE, S100ββ, and ITIH4 showed a differential expression in both the outcome groups of AIS patients, irrespective of diabetes.

CONCLUSION

Diabetes increases the risk of dependent/expired outcome in AIS patients. Also, serum NSE, S100ββ, and ITIH4 are independent biomarkers for prognosis of outcome in AIS patients, irrespective of diabetes.

Neuron specific enolase: a promising therapeutic target in acute spinal cord injury

Enolase is a multifunctional protein, which is expressed abundantly in the cytosol. Upon stimulatory signals, enolase can traffic to cell surface and contribute to different pathologies including injury, autoimmunity, infection, inflammation, and cancer. Cell-surface expression of enolase is often detected on activated macrophages, microglia/macrophages, microglia, and astrocytes, promoting extracellular matrix degradation, production of pro-inflammatory cytokines/chemokines, and invasion of inflammatory cells in the sites of injury and inflammation. Inflammatory stimulation also induces translocation of enolase from the cytosolic pool to the cell surface where it can act as a plasminogen receptor and promote extracellular matrix degradation and tissue damage. Spinal cord injury (SCI) is a devastating debilitating condition characterized by progressive pathological changes including complex and evolving molecular cascades, and insights into the role of enolase in multiple inflammatory events have not yet been fully elucidated. Neuronal damage following SCI is associated with an elevation of neuron specific enolase (NSE), which is also known to play a role in the pathogenesis of hypoxic-ischemic brain injury. Thus, NSE is now considered as a biomarker in ischemic brain damage, and it has recently been suggested to be a biomarker in traumatic brain injury (TBI), stroke and anoxic encephalopathy after cardiac arrest and acute SCI as well. This review article gives an overview of the current basic research and clinical studies on the role of multifunctional enolase in neurotrauma, with a special emphasis on NSE in acute SCI.

Drug-induced therapeutic hypothermia after asphyxial cardiac arrest in swine

A feasibility study was performed to compare an investigational drug, HBN-1, to forced cooling to induce hypothermia after resuscitation in a translation model of asphyxial cardiac arrest in swine. Serum and cerebral spinal fluid neuron-specific enolase activity (sNSE and csfNSE) were measured after cardiac arrest as surrogate markers of brain injury. In a block design, swine resuscitated from 10 minutes of asphyxial cardiac arrest were infused intravenously with HBN-1 or iced saline vehicle (forced hypothermia [FH]) 5 to 45 minutes after return of spontaneous circulation (ROSC). External cooling in both groups was added 45 minutes after ROSC until hypothermia (T=4°C below baseline) was attained. Esophageal (core) temperature, shivering, cardiopulmonary parameters, and time to hypothermia after ROSC were monitored. sNSE and csfNSE were measured 180 minutes after ROSC. HBN-1 induced hypothermia significantly lowered temperature compared to FH 5-45 minutes after ROSC (p<0.0001). Time to hypothermia was reduced by HBN-1 (93±6 minutes) compared to FH (177±10 minutes) (p<0.0001). HBN-1 sNSE (0.7±1.9 ng/mL) and csfNSE (17.3±1.9 ng/mL) were lower compared to FH (6±1.6 ng/mL) and (49.7±32.0 ng/mL) (p<0.0001, p=0.022, respectively). There was no shivering with HBN-1 cooling while all FH cooled swine shivered (p<0.0001). The time to reach target hypothermia after cardiac arrest was reduced by nearly 50% with HBN-1 compared to the FH method of inducing hypothermia. Moreover, surrogate biomarkers of brain injury were significantly reduced with HBN-1 as compared to FH. While HBN-1-induced hypothermia shows promise for being neuroprotective, survival studies are needed to confirm these preliminary findings.

Neuron specific enolase and c-reactive protein levels in stroke and its subtypes: correlation with degree of disability

Stroke is an emergency which threatens life and third leading cause of death and long term disability in developed countries. The use of biomarkers in diagnosing stroke and assessing prognosis is an emerging and rapidly evolving field. The study aimed to investigate the predictive value of biochemical marker of brain damage neuron-specific enolase (NSE) and systemic inflammatory marker C-reactive protein (CRP) with respect to degree of disability at the time of admission and short term in stroke patients. We investigated 120 patients with cerebrovascular stroke who were admitted within 72 h of onset of stroke in the Department of Neurology at Sri Aurobindo Institute of Medical Sciences, Indore, India. NSE and CRP were analyzed by solid enzyme linked immunosorbent assay using analyzer and micro plate reader from Biorad 680. In all patients, the neurological status was evaluated by a standardized neurological examination and the National Institutes of Health Stroke Scale on admission and on day 7. Serum NSE and CRP concentration were found significantly increased in acute stroke cases as compared to control in present study (<0.05 and <0.001 respectively). The maximum serum NSE and CRP levels within 72 h of admission were significantly higher in patients with greater degree of disability at the time of admission. Both biomarkers were found significantly correlated with neurological disability and short term outcome. Our study showed that serum biomarkers NSE and CRP have high predictive value for determining severity and early neurobehavioral outcome after acute stroke.

NSE, a potential biomarker, is closely connected to diabetic peripheral neuropathy

OBJECTIVE

To explore the relationship between serum neuron-specific enolase (NSE) levels and diabetic neuropathy.

RESEARCH DESIGN AND METHODS

Type 1 or 2 diabetic and healthy control subjects (n = 568) were randomly enrolled in a cross-sectional study. Diabetic neuropathy status was documented by the presence of clinical symptoms or signs, electromyography, quantitative sensory tests, and cardiac autonomic neuropathy tests. The severity of the neuropathy was staged by composite scores. Serum NSE was measured using electrochemiluminescence immunoassay. The demographic and clinical variables were obtained through an interviewer questionnaire.

RESULTS

Serum NSE levels increased slightly in diabetic subjects compared with normal subjects (9.1 [1.5] vs. 8.7 [1.7], P = 0.037), and the levels increased greatly in diabetic subjects with neuropathy compared with those without (10.8 [2.8] vs. 9.1 [1.5], P = 0.000). The association of NSE with diabetic neuropathy was independent of the hyperglycemic state (fasting blood glucose, HbA1c, duration, and the type of diabetes) and other potential confounders affecting NSE levels (e.g., age, sex, and renal status) (odds ratio 1.48 [1.13-1.74], P = 0.001). In addition, NSE levels increased with and were closely correlated to the stages of neuropathy (r = 0.63 [0.52-0.74], P = 0.000). The optimal cutoff point for serum NSE levels to distinguish patients with diabetic neuropathy from those without was 10.10 μg/L, with a sensitivity of 66.3% and a specificity of 72.5%.

CONCLUSIONS

Serum NSE levels are closely associated with peripheral neuropathy in patients with diabetes. Future studies are warranted to clarify the relationship.