Evaluation of serum h-type fatty acid-binding protein and neuron-specific enolase levels in acute ischemic stroke patients

A biomarker routinely used in ischemic stroke is not yet available. The aim of this study was to determine heart-fatty acid binding protein (H-FABP) and neuron-specific enolase (NSE) could be used as valid diagnostic and prognostic biomarkers for acute ischemic stroke. This study was approved by Baskent University Institutional Review Board and Ethics Committee (Project no: KA19/325) and supported by Baskent University Research Fund. Our analysis included 54 patients in case group diagnosed with acute ischemic stroke and we compared results with a control group of 26 patients whom any other diagnosis within the time period we determined. 5 ml of peripheral venous blood samples were taken from all patients (n=80) for NSE and H-FABP within the first 24 hours of admission, and samples were analyzed by enzyme-linked immunosorbent assay (ELISA) method for both biomarkers. The power of H-FABP and NSE values in differentiating the diagnosis of ischemic stroke was evaluated by the area under the ROC curve (AUC). The relationship of serum NSE and H-FABP levels with stroke severity, infarct size, stroke localization, and outcomes (functional outcome, hospitalization, death) was investigated. The study data was analyzed with SPSS for Windows v20.0 software, and p values <0.05 were considered statistically significant. We obtained statistically similar results in terms of sociodemographic characteristics in case and control groups (>0.05). The area under the ROC curve was not statistically significant for each biomarker in predicting the diagnosis of ischemic stroke. The AUC value for H-FABP and NSE were 0.535 (95% CI: 0.401-0.669), and 0.494 (95% CI: 0.360-0.627), respectively. We found no difference between the case and control groups for median values of both H-FABP and NSE levels compared (3.21 ng/ml vs. 3.15 ng/ml for H-FABP; p = 0.615, 10.5 ng/ml vs. 11.59 ng/ml for NSE; p = 0.926). There was no correlation between the biomarkers with infarct area (r = -0.105 p = 0.452, r = -0.050 p = 0.717, respectively), NIHSS score (r = 0.102 p = 0.463, r = -0.086 p = 0.538, respectively) and duration of symptoms (r = 0.085 p = 0.541; r = -0.031 p = 0.823, respectively). Speech disorder was the most common symptom in stroke group (40.7%), and stroke patients with speech disorders had higher NSE levels (median values of 15.23 ng/ml vs. 9.28 ng/ml, respectively; p = 0.01), but no significant relationship between H-FABP levels and initial symptoms. Both biomarkers were not significant in definition the vascular region responsible for stroke (>0.05). We found no significant results for both biomarkers in predicting 3-month mortality and the need for hospitalization. However, H-FABP values were higher in patients recovered with favorable functional outcome at discharge (3.54 ng/ml vs. 2.95 ng/ml; p = 0.048). Our results did not provide significant evidence for the utility of H-FABP and NSE levels as part of the diagnostic and prognostic processes in patients with acute ischemic stroke presenting to the emergency department. More randomized prospective studies with selected methodology should be designed before these biomarkers can be used routinely. Keywords: NSE, H-FABP, ischemic stroke, biomarker