Project: Fecal Gut Microbiome Drives the Gallstone Formation Evidenced on Human Metagenomic Profiling and Fecal Microbiota Transplantation in Mice

Gallstone and associated diseases are the increasing healthcare burden worldwide, but the pathogenesis of gallstones is still unclear. In this study, we aimed to clarify the involvement of gut microbiota in the pathogenesis of gallstone formation. Methods: Fresh fecal samples were collected from 18 gallstone patients and 18 healthy controls and subjected to whole-metagenome shotgun sequencing. Furthermore, after receiving a course of antibiotics cocktail to deplete intestinal microbes, C57BL/6 mice were gavaged with stool from either six patients with gallstone or healthy controls. The gallstone and bile crystal formation were investigated in gallbladder derived from these mice using macroscopy, phase contrast and polarizing light microscope. Mice fecal samples were also analyzed by 16S ribosomal RNA gene sequencing. Results: The gallstone patients displayed a remarkable gut microbial dysbiosis in both composition and functions. Escherichia coli, Lactobacillus fermentum and Klebsiella pneumoniae were enriched in gallstone patients, whereas Eubacterium eligens, Eubacterium sp. CAG:38 and Clostridium sp. CAG:7 were enriched in healthy controls. The optimal cluster of 20 microbial markers was identified on a random forest model and achieved an area under the receiver operator characteristic curve of 85.5%. Notably, gut microbial biomarkers validated strong predicted potential for gallstone formation and the microbial functions of gallstone patients are highly associated with metabolism and human diseases. C57BL/6 mice fed with lithogenic diet and gavage with stool from gallstone patients presented higher gallstone incidence and induced gut microbiota dysbiosis than the counterpart of healthy controls, as well as PBS group. Conclusions: Our results reveal that altered gut microbial play vital and driving roles on gallstone formation.