Gut microbiome dysbiosis contributes to abdominal aortic aneurysm by promoting neutrophil extracellular trap formation.

Abdominal aortic aneurysm (AAA) is an insidious and lethal vascular disease that lacks effective nonsurgical interventions. Gut microbiota dysbiosis plays key roles in many diseases, but its relationship with AAA has not been fully elucidated. Herein, we reveal significant abnormalities in the gut microbe composition of AAA patients and confirm that gut microbiota dysbiosis is an important cause of AAA. Specifically, R. intestinalis was significantly reduced in AAA patients. Using AAA mice, we show that R. intestinalis and its metabolite butyrate significantly reduce neutrophil infiltration and NOX2-dependent neutrophil extracellular trap formation, inflammation, and abnormal phenotypic switching of vascular smooth muscle cells in the aortic wall, thereby markedly alleviating AAA development. Our research uncovers the role and mechanism of the gut microbiota in AAA development and provides insights into AAA prophylaxis from a microecological perspective.