Evaluation of Neurofilament Light Chain as a Biomarker in Dogs with Structural and Idiopathic Epilepsy

The objective of this prospective cohort study is to assess the use of neurofilament light chain (NfL) as a biomarker for diagnostic and therapeutic monitoring in dogs with idiopathic and structural epilepsy. A total of 50 dogs (36 idiopathic epilepsy and 14 structural epilepsy) were enrolled to contribute a total of 58 samples (52 serum and 6 cerebrospinal fluid (CSF)). Dogs diagnosed with structural epilepsy received magnetic resonance imaging (MRI). Dogs were grouped into acute seizures when they had a generalized seizure within the last 7 days and chronic seizures when they had no observed generalized seizures for the previous 30 days. Both serum and CSF NfL concentrations were measured using single molecule array technology (Simoa). The median serum concentration of NfL in dogs with structural epilepsy was 109 [11.4-741.3] pg/mL and 17.7 [5.8-188] pg/mL in dogs with idiopathic epilepsy regardless of the interictal interval. Serum NfL concentration was significantly increased in dogs with structural epilepsy when compared with dogs with idiopathic epilepsy (p < 0.001). There was no significant difference in NfL concentration in dogs with an interictal interval of 7 days compared to dogs with an interictal interval of 30 days. In dogs with seizures, serum NfL concentration may help discriminate between structural and idiopathic epilepsy. Future studies are needed to determine its role in differentiating true seizure events from seizure mimics.