Investigation of gastrointestinal microbiota characteristics inpediatric epilepsy patients

Epilepsy is one of the most common chronic neurological diseases of childhood, and the role of the gut-brain axis in its pathophysiology is gaining increasing importance. The aim of our study is to investigate the presence of a potential disease-specific microbial signature by comparing the gut microbiota characteristics of children diagnosed with epilepsy with those of a healthy control group. Our study included 20 children diagnosed with epilepsy and 20 healthy children, aged 4-12 years. Microbiota analysis was performed on fecal samples collected from participants using the 16S rRNA gene sequencing method. No significant difference was found between the groups in terms of demographic data. While no statistical difference was observed between the groups in microbial diversity analyses (alpha and beta), significant changes were detected in taxonomic composition. The epilepsy group showed a significant decrease compared to the healthy group in the phylum Bacteroidota (23.6% vs. 33.9%) and the genus Bacteroides (15.4% vs. 26.4%). Conversely, the relative abundance of the genera Bifidobacterium (13.02% vs. 4.98%) and Akkermansia (9.43% vs. 4.07%), which are associated with immunomodulation, was markedly increased in the epilepsy group. Linear Discriminant Analysis Effect Size (LEfSe) analysis revealed that the healthy group was most strongly characterized by Bacteroides vulgatus (Linear Discriminant Analysis [LDA] score: 5.02), whereas the epilepsy group was characterized by Bifidobacterium longum (LDA score: 4.80). In conclusion, our study has shown that pediatric epilepsy is associated with a distinct dysbiotic signature without a loss in overall microbial diversity. This is characterized by a decrease in key beneficial genera such as Bacteroides and an increase in genera that can influence the immune system. Our study is one of the pioneering studies in this field in our country, and its findings strongly support the hypothesis that the gut- brain axis contributes to the pathophysiology of epilepsy. We anticipate that these results will contribute to the future development of microbiota-targeted diagnostic biomarkers and therapeutic strategies. Key Words: epilepsy, gut microbiota, dysbiosis, gut-brain axis