Objectives: An altered microbiota, which can be described quantitatively, has been identified as playing a pivotal role in host vascular physiology, and it may contribute to various diseases. The aim of this study was to better understand the role of the gut microbiota in vascular physiology in a subclinical elderly population, and to investigate how lifestyle affects the composition of host gut microbiota to further impact the pathogenesis of vascular diseases.
Methods: We performed a population-based faecal metagenomic study over 569 elderly asymptomatic subclinical individuals in rural China. An association network was built based on clinical measurements and detailed epidemiologic questionnaires, including blood chemistry, arterial stiffness, carotid ultrasonography, and metagenomic datasets.
Results: By analyzing the breadth, depth and impact of each node of the association network, we found carotid arterial atherosclerosis indices, including intima-media thickness (IMT), were essential in the network, and were significantly associated with living habits, socio-economic status, and diet. Using mediation analysis, we found that higher frequency of eating fresh fruits and vegetables, and more exercise significantly reduced carotid atherosclerosis in terms of IMT, peak systolic velocity and end-diastolic velocity values through the mediation of Alistepes, Oligella and Prevotella. Gut microbes explained 16.5% of the mediation effect of lifestyle on the pathogenesis of carotid atherosclerosis. After adjustment, Faecalicatena [odds ratio (OR) = 0.12 ∼0.65] was shown to be protective against the formation of carotid atherosclerosis, independently, while Libanicoccus (OR = 1.46 ∼4.20 ) was associated with increased carotid arterial IMT. KEGG/KO Kyoto Encyclopedia of Genes and Genomes/ KEGG Orthology (KEGG/KO) analyses revealed a loss of anti-inflammation function in IMT subjects.
Conclusion: Our study revealed a Chinese population-wide phenotype-metagenomic association network and a mediation effect of gut microbiota on carotid artery atherosclerosis, hinting at potential therapeutic and preventive uses for microbiota in vascular diseases.
Keywords: carotid artery atherosclerosis; gut microbiome; intima-media thickness; mediation analysis; metagenomics.
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