Abstracts

Rationale: Several studies demonstrated that the short-term consumption of diets composed of animal or plant products alters the composition of microorganisms and makes inter-individual differences in microbial gene expression as well as long-term dietary intake of microorganisms residing in the human gut. The main objective of this study is to evaluate underlying dysbiosis and its relationship to intractable epilepsy of children treated with ketogenic diet (KD) as comparing their microbiome composition before and after KD.The main objective of this study is to evaluate underlying dysbiosis and its relationship to intractable epilepsy of children treated with KD as comparing their microbiome composition before and after KD.  Methods: This was a prospective, observational study of the effects of the KD on gut microbiota profile in pediatric patients with intractable epilepsy. All enrolled patients were childhood with intractable epilepsy from February 2017-March 2018 at Severance Children's Hospital in Korea. And gut microbiota profile were analyzed at college of Life Sciences and Biotechnology of Korea University in Korea. All patients were monitored for at least 1 month after the KD. The main outcome measures were the changes from the baseline of large intestine microbiota composition through the analysis of fecal samples. Results: Sixteen patients (boys 10; girls 6) were finally enrolled. Ten (62.5%) patients were instructed to maintain 3:1 KD, and the others maintained Atkins Diet. Responders who had more than 50% reduction in their seizures on the KD was 9 (56.3%) of 16 children at 1 months. Short chain fatty acids were analyzed with using GC/MS. Short chain fatty acids in fecal samples at 1 month after KD were increased in iso-butyrate and butyrate in, compared to the fecal samples before KD. PCA analysis performed with operational taxonomic unit (OTU) level profile showed differences in two samples. They were peptoclostridium and Bifidobacterium. In genus level profile, only 30 abundant genera (>0.5% total abundance) were noted. Alpha diversity with diagnostic exome sequencing indicated more different among individuals than between before and after KD. When we analyzed the data with OTU, we found decreased bifidobacterium and increased Escherichia shigellaha in fecal samples in after KD than in samples before KD.  Conclusions: The occurrence of an underlying dysbiosis has rarely been investigated in patients on a classical KD and no specific recommendations on probiotic or prebiotic supplementation have been included so far in practical guidelines on the implementation of ketogenic diet in epilepsy. It may be reasonable to consider an empiric trial of pre or probiotics to potentially restore the ecological balance of intestinal microbiota. Anti-epileptic effect and mechanisms of synbiotic-supplemented ketogenic diet in in vitro- and in vivo seizure models.  Funding: No funding