Identification of Serum Biomarkers for Differentiating Epileptic Seizures from Psychogenic Attacks Using a Proteomic Approach; a Comparative study

ntroduction:Differentiating actual epileptic seizures (ESs) from psychogenic non-epileptic seizures (PNES) isof great interest. This study compares the serum proteomics of patients diagnosed with ESs and PNES.Meth-ods:Eight patients with seizure (4 with PNES and 4 with TLE (temporal lope epilepsy)) were enrolled in thiscomparative study. Venous blood samples were drawn during the first hour following the seizure. Standard pro-tein purification technique was employed and proteins were subsequently separated via 2-D electrophoresis.After comparison of the serum proteomes from the two groups, protein expression was analyzed. The differen-tially expressed bands were determined using both matrix-assisted laser ionization time-of-flight (MALDI/TOF)and electrospray ionization quadruple mass spectrometry (MS).

This study identified 361 proteins, theexpression of 110 proteins increased, and 87 proteins decreased in the PNES group compared with TLE group.Four separate proteins were finally identified with MALDI/TOF MS analysis. Compared with PNES group, al-pha 1-acidglycoprotein 1, ceruloplasmin, and S100-βwere down-regulated and malate dehydrogenase 2 wasup-regulated in the serum of TLE patients.

Our results indicated that changes in serum levelsof S100-β, ceruloplasmin, alpha 1-acidglycoprotein 1, and malate dehydrogenase 2 after seizure could be intro-duced as potential markers to differentiate ES from PNES; however, more advanced studies are required to reacha better understanding of the underlying mechanisms.