The alteration of gut microbiota composition in patients with epilepsy: A systematic review and meta-analysis

There is accumulating evidence suggesting a connection between epilepsy, a neurologic disease with recurrent seizures, and gut microbiota. This systematic review and meta-analysis explores the alterations of GM composition in patients with epilepsy.

A systematic search was conducted up to June 26, 2024, across PubMed, Scopus, Web of Science, and Embase. The study outcomes were α- and β-diversity indexes, and relative abundance at different bacterial taxonomic levels, compared between epilepsy patients and healthy controls. Inverse variance-weighted meta-analysis was performed to estimate the standardized mean difference. We utilized the Newcastle-Ottawa Scale (NOS) to assess the quality of the included studies.

In this systematic review, we included 16 case-control studies encompassing 438 cases and 369 controls, and 12 studies were included in the meta-analyses. α-diversity was not significantly different between epilepsy and control group. Of the 11 studies measuring β-diversity, 8 studies showed that the microbiota compositions of the two groups differed significantly. Verrucomicrobia was significantly higher in the epilepsy group (SMD = 0.39 [0.05, 0.72], p = 0.022) than in the control group. At the genus level, Roseburia (SMD = -0.50 [-0.84, -0.17], p = 0.003), Blautia (SMD = -0.40 [-0.73, -0.06], p = 0.022), and Dialister (SMD = -0.40 [-0.74, -0.07], p = 0.018) were significantly less abundant in patients with epilepsy.

Our findings evince remarkable changes in gut microbiota composition in epilepsy. Bacterial genera that promote neuroinflammation are elevated in epilepsy. Our study revealed the interrelation between GM disruption and epileptogenesis, but the heterogeneity among the included results was high, and further investigation is encouraged.