Altered intestinal bacterial communities increase the risk of intracranial aneurysms

Decreased vessel wall function and elasticity lead to intracranial aneurysms (IAs), which increase the risk of vessel rupture. The association between IA formation and gut flora remains unclear. Therefore, we compared the gut microbiomes of patients with IAs with those of healthy controls (HCs) to identify specific bacteria associated with IAs. This single-center prospective case-control study was conducted from July 2022 and February 2023. Stool samples were collected from patients with unruptured IAs and HCs. The bacterial communities of patients with IAs were compared with those of healthy controls using 16SrRNA sequencing technology. In addition, phylogenetic trees were constructed to identify specific species. Twenty-five patients with IAs and 30 HCs were included in this study. There were no significant differences in age, sex, body mass index, hypertension, diabetes mellitus, dyslipidemia, smoking, or alcohol consumption rates between the two groups. Diversity analysis indicated no significant difference in alpha diversity; however, there was a significant difference in beta diversity with respect to the unweighted UniFrac distance. Linear discriminant analysis combined with effect size measures showed that several intestinal microbiome taxonomic profiles were significantly enriched in samples from patients in the IA group. Helicobacter species were our point of concern as they are widely considered pathogenic. Thus, we constructed a Helicobacter -related phylogenetic tree and identified three species, Helicobacter pullorum , Helicobacter typhlonius , and Helicobacter rodentium . The gut microbiome profiles of patients with stable, unruptured IAs differed significantly from those of HCs. Therefore, the genus Helicobacter may be associated with IA formation.