Altered gut microbiomes are associated with the symptomatic status of unruptured intracranial aneurysms

Abstract

BackgroundGut microbiome has recently been recognized as an important environmental factor affecting the occurrence and development of unruptured intracranial aneurysms (UIA). This study aimed to investigate the relationship between gut microbiome and symptomatic UIA, which is a predictor of instability and a high propensity to rupture.MethodsA total of 132 patients including 86 asymptomatic UIA and 46 symptomatic UIA were recruited in the study. The composition of gut bacterial communities was determined by 16S ribosomal RNA gene sequencing. In addition, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predict the functional composition of the gut microbiome.ResultsThere is no difference in the fecal microbial alpha diversity between symptomatic and asymptomatic UIA, but gut microbiome composition changed significantly. At the order level, the relative abundance of Clostridiales was significantly enriched in the symptomatic compared with asymptomatic UIA (p = 0.043). In addition, similar alterations were observed at the family levels of Ruminococcaceae. The Linear discriminant analysis (LEfSe) revealed Fournierella, Ruthenibacterium, and Anaerotruncus as discriminative features in the symptomatic group. Notably, functional differences in gut microbiome of patients with symptomatic UIA included decreased propionate metabolism pathway and enrichment of peptidoglycan biosynthesis pathways.ConclusionThe present study comprehensively characterizes gut microbiome in a large cohort of different risk statuses of UIA patients and demonstrates the potential biological function of gut microbiome involved in the development of UIA. It may provide additional benefits in guiding UIA management and improving patient outcomes.

Gut microbiome in intracranial aneurysm growth, subarachnoid hemorrhage, and cerebral vasospasm: a systematic review with a narrative synthesis

“…After the de-duplication process, 62 abstracts were evaluated for eligibility criteria. Subsequently, the curation of seven full texts allowed for narrowing down the results to four eligible studies that met the inclusion criteria—see Figure 1 (Shikata et al, 2019 ; Li et al, 2020 ; Kawabata et al, 2022 ; Sun et al, 2022 ). Of these, three publications sought the relationship between intestinal microbiota and the growth of intracranial aneurysms (Shikata et al, 2019 ; Li et al, 2020 ; Sun et al, 2022 ).…”

“…Subsequently, the curation of seven full texts allowed for narrowing down the results to four eligible studies that met the inclusion criteria—see Figure 1 (Shikata et al, 2019 ; Li et al, 2020 ; Kawabata et al, 2022 ; Sun et al, 2022 ). Of these, three publications sought the relationship between intestinal microbiota and the growth of intracranial aneurysms (Shikata et al, 2019 ; Li et al, 2020 ; Sun et al, 2022 ). Two articles evaluated microbiome in subjects with subarachnoid hemorrhage due to rupture of the aneurysm (Li et al, 2020 ; Kawabata et al, 2022 ).…”

“…Three studies reported an association between dysbiosis of gut microbiota and aneurysm progression (Shikata et al, 2019 ; Li et al, 2020 ; Sun et al, 2022 ). Shikata et al ( 2019 ) presented an experimental animal model of aneurysm formation in mice whose gut microbiota was antibiotically depleted.…”

“…To date, there has been only one study comparing the gut microbiota of symptomatic UIA subjects with asymptomatic UIA. Sun et al ( 2022 ) reported results of a study comparing 46 symptomatic UIA and 86 asymptomatic UIA, excluding any patients with a history of aSAH. Fecal samples were collected upon admission, and DNA was extracted and sequenced using the Illumina NovaSeq platform (San Diego, CA, United States)—a summary of the methodology is listed in Supplementary material 1 .…”

“…The metabolic activity of microbiota was also found to be discriminative with regard to symptomatic manifestation. Among the symptomatic patients, propionate biosynthesis was found to be diminished, and peptidoglycan synthesis was elevated (Sun et al, 2022 ). Indeed, short-chain fatty acid propionate maintains microglial functions and might serve as a protective intervention against cerebrovascular damage secondary to hypertension (Hoyles et al, 2018 ; Bartolomaeus et al, 2019 ).…”