Use of neuron-specific enolase for assessing the severity and outcome in patients with neurological disorders.

J.E Lima,J.P Leite,O.M Takayanagui,L.V Garcia

doi:10.1590/s0100-879x2004000100003

Abstract

Neuron-specific enolase (NSE) is a glycolytic enzyme present almost exclusively in neurons and neuroendocrine cells. NSE levels in cerebrospinal fluid (CSF) are assumed to be useful to estimate neuronal injury and clinical outcome of patients with serious clinical manifestations such as those observed in stroke, head injury, anoxic encephalopathy, encephalitis, brain metastasis, and status epilepticus. We compared levels of NSE in serum (sNSE) and in CSF (cNSE) among four groups: patients with meningitis (N=11), patients with encephalic injuries associated with impairment of consciousness (ENC, N=7), patients with neurocysticercosis (N=25), and normal subjects (N=8). Albumin was determined in serum and CSF samples, and the albumin quotient was used to estimate blood-brain barrier permeability. The Glasgow Coma Scale score was calculated at the time of lumbar puncture and the Glasgow Outcome Scale (GOS) score was calculated at the time of patient discharge or death. The ENC group had significantly higher cNSE (P=0.01) and albumin quotient (P=0.005), but not sNSE (P=0.14), levels than the other groups (Kruskal-Wallis test). Patients with lower GOS scores had higher cNSE levels (P=0.035) than patients with favorable outcomes. Our findings indicate that sNSE is not sensitive enough to detect neuronal damage, but cNSE seems to be reliable for assessing patients with considerable neurological insult and cases with adverse outcome. However, one should be cautious about estimating the severity of neurological status as well as outcome based exclusively on cNSE in a single patient.

Highlights

Enolase (2-phospho-D glycerate hydrolyase or phosphopyruvate hydratase, EC 4.2.1.11) is a glycolytic enzyme that converts 2-phospho-D glycerate to phosphoenolpyruvate
The ENC group had higher levels of cNSE (*P = 0.01) and Qalb (*P = 0.0047), but not of sNSE (P = 0.14), compared to the other groups (Kruskal-Wallis test followed by the Dunn test)
The present findings indicate that patients in the ENC group had higher cNSE levels than patients from the other groups

Summary

Introduction

Enolase (2-phospho-D glycerate hydrolyase or phosphopyruvate hydratase, EC 4.2.1.11) is a glycolytic enzyme that converts 2-phospho-D glycerate to phosphoenolpyruvate. It is a protein which is functionally active as a heterodimer assembled from a combination of three subunits: α, ß and γ [1]. The γ γ and αγ isoenzymes are referred to as neuron-specific enolase (NSE) [2,3] because it was initially thought that these isoenzymes were exclusively found in neurons [4]. The encephalic NSE concentration ranges from 0.4 to 2.2%, and may represent up to 4% of the total soluble proteins in some neurons [3]. Higher concentrations of NSE are found in the gray matter (e.g., neocortex) and lower levels in the white matter (e.g., pyramidal tract and corpus callosum) [2]

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