Metabonomic analysis of cerebrospinal fluid in epilepsy

BACKGROUND: We sought to explore the relationship between epilepsy and cerebrospinal fluid metabolomics and identify biomarkers for the diagnosis, treatment, and prognosis of epilepsy. METHODS: In total, 23 epileptic patients treated at The First Affiliated Hospital of Dalian Medical University from April 2019 to September 2019 were selected for the disease group and 13 non-epileptic patients were selected for the control group. Cerebrospinal fluid samples were collected from both groups, and the metabolites were analyzed by gas chromatography–mass spectrometry. The metabolites differentially expressed in the cerebrospinal fluid samples were identified. A differential metabolite enrichment analysis was performed to determine the metabolic pathways. RESULTS: Using a variable importance in the projection value >1 and a P value <0.05 as the screening criteria, we found that 3 metabolites (i.e., alpha-ketoisocaproic acid 1, xylose 1, and glycine 2) were differentially expressed in the cerebrospinal fluid of the 23 epileptic patients compared to the 13 non-epileptic patients. Alpha-ketoisocaproic acid 1 and xylose 1 were highly expressed in the epileptic cerebrospinal fluid samples, while glycine 2 was lowly expressed in the epileptic cerebrospinal fluid samples. Additionally, the 3 metabolites were significantly enriched in the 5 metabolic pathways of primary bile acid biosynthesis, valine, leucine, and isoleucine degradation, glutathione metabolism, glyoxylate and dicarboxylate metabolism, and glycine, serine, and threonine metabolism. CONCLUSIONS: The present study examined the metabolites of the cerebrospinal fluid of epileptic patients and non-epileptic patients. Our findings provide insights that may inform the discovery of therapeutic targets and diagnostic markers for epilepsy.