The gut microbiota in experimental abdominal aortic aneurysm.

Area of Science:

• Microbiology
• Vascular Biology
• Gastroenterology

Background:

• Abdominal aortic aneurysm (AAA) is a life-threatening condition lacking effective treatments.
• The gut microbiota's role in host homeostasis is recognized, but its specific involvement in AAA remains unclear.
• Investigating gut microbiota composition is crucial for understanding AAA pathogenesis.

Purpose of the Study:

• To compare the gut microbiota composition between mice with AAA and control groups.
• To identify potential microbial biomarkers and pathways associated with AAA development.
• To explore the role of gut bacteria in AAA formation.

Main Methods:

• Utilized the angiotensin-II induced AAA mouse model.
• Administered Angiotensin II (Ang II) to induce AAA in mice (n=13) versus saline controls (n=7).
• Analyzed fecal samples using 16S rRNA sequencing and employed PICRUSt2 for metabolic pathway analysis.

Main Results:

• Significant differences in gut microbiota composition were observed between AAA and control groups.
• Increased levels of specific bacteria (e.g., Oscillospira, Ruminococcus gnavus) in AAA group; decreased levels of others (e.g., Akkermansia muciniphila) in control group.
• Bacteroidetes species identified as keystone, with specific metabolic pathways (L-tryptophan biosynthesis, sulfoglycolysis) and bacteria (E. coli/Shigella) implicated in AAA.

Conclusions:

• Gut microbiota dysbiosis is associated with abdominal aortic aneurysm formation.
• Decreased Akkermansia and Lactobacillus in AAA suggest potential protective roles.
• Further research on Bacteroidetes keystone species and their metabolic products is warranted for AAA pathogenesis.