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.