Abstract Body: Introduction: The human microbiome has been studied in various diseases, including inflammatory bowel disease, diabetes, obesity, and cardiovascular diseases. However, its role in acute ischemic stroke (AIS) remains underexplored. This study aims to investigate the microbiome profiles in stool and saliva samples from AIS patients compared to control groups to identify distinct microbial patterns associated with ischemic stroke.
Methods: We enrolled 54 AIS patients, collecting stool and saliva samples within one week of admission. Saliva was either self-expectorated (n=44) or obtained via oral swab (n=10) for those unable to spit. The 40 control group was defined as those without cerebrovascular disease, in whom no abnormalities were found on brain MRI/A taken for health check-up purposes within the past year. DNA extraction and 16S rRNA gene sequencing were performed, and data were analyzed using QIIME 2 for diversity and taxonomy, with Linear discriminant analysis Effect Size (LEfSe) for differential abundance and functional predictions.
Results: AIS patients demonstrated significantly higher alpha diversity in stool samples compared to controls (p=0.001), indicating increased microbial richness. Saliva samples, however, showed decreased microbial richness in AIS patients (p=0.024). Beta diversity analysis revealed distinct microbial community structures between AIS patients and controls, especially at the genus level in stool samples (p=0.001). LEfSe analysis identified several bacterial taxa enriched in AIS patients' stool, while saliva samples from AIS patients exhibited a higher number of depleted taxa compared to controls. Notably, the AIS microbiome showed reduced functional capabilities related to beneficial metabolic processes including Proteobacteria, Gammaproteobacteria, Enterobacteriaceae, and Shigella, etc. These findings highlight a potential link between microbiome dysbiosis and the pathophysiology of AIS.
Conclusions: This study identifies significant microbiome dysbiosis in AIS patients, characterized by altered diversity and bacterial composition in stool and saliva samples. The findings suggest that gut and oral microbiomes may contribute to the pathophysiology of cerebral infarction, warranting further investigation into their roles as potential biomarkers or therapeutic targets.