Serum biomarkers of seizure-related neuronal damage and astroglial activation in epileptic seizures and epilepsy

BACKGROUND: Epileptology has an urgent need for easily accessible fluid biomarkers for improving diagnosis, subclassification and prognostication. In various neurological diseases Neurofilament Light chain (NfL) and Glial Fibrillary Acidic Protein (GFAP) have emerged as promising blood biomarkers of neuroaxonal damage and astrocytic activation, respectively. Their role in epileptic seizures and epilepsy has so far been scarcely explored and their potential has not been assessed systematically in patients with epileptic conditions. METHODS: We systematically assessed the role of serum NfL and GFAP in our single-centered prospective cohort of 108 patients with epileptic seizures and epilepsy. We analyzed biomarker levels in clinical subgroups and a control group of 48 individuals without any degenerative or structural neurological disease. We further compared the value of NfL and GFAP to well-established markers such as lactate, creatine kinase and myoglobin. RESULTS: Elevated GFAP but not NfL levels were associated with recent epileptic seizures (n = 25, GFAP p = 0.0227, NfL p = 0.1227) and epilepsy (n = 83, GFAP p = 0.008, NfL p = 0.076) in general and in various subgroups when compared to controls. In patients with single seizures and sampling obtained shortly after a seizure (n = 25) myoglobin (p = 0.0021, AUC=0.847) performed better than NfL (p = 0.1227, AUC=0.73) or GFAP (p = 0.0227, AUC=0.682). Neither NfL nor GFAP could distinguish between semiological or etiological subgroups. None of the biomarkers showed prognostic potential regarding seizure recurrence. CONCLUSIONS: Serum NfL and GFAP represent novel biomarkers for patients with epileptic conditions and show a dynamic profile after seizure.