Cholelithiasis (presence of stones in the gallbladder) is a very common condition affecting 10-15% of adults in Europe and the USA. This makes it the most common gastrointestinal disorder requiring hospitalization. The pathogenesis of Cholelithiasis isn’t fully established, but new research suggests that dysbiosis could be an important underlying cause. Cholelithiasis can then be added to the growing list of diseases associated with alterations in the human microbiome.
Researchers studied the composition of bacterial communities of gut, bile, and gallstones from 29 gallstone patients as well as the gut of 38 normal individuals. Analysis of the samples showed three major differences between healthy individuals and patients with gallstones:
Significant differences in the composition of the gut microbiota
Cholelithiasis was associated with an increase of the bacterial phylum Proteobacteria, which generally suggests an overgrowth of pathogens previously linked to gastrointestinal disorders.
The analysis also showed reductions in three gut bacterial genera in patients with gallstones, indicating a possible link between the co-occurence of these bacteria and Cholelithiasis.
Significant differences in the composition of the biliary tract microbiota
The biliary tract is the path by which bile is secreted by the liver and then transported to the first part of the small intestine. In gallstone patients, around 70% of gut bacterial operational taxonomic units were detected in the biliary tract, suggesting that the bacteria in the biliary tract could originate from the gut. The bacterial diversity of the biliary tract was significantly higher than that of the gut.
Certain bacteria in the biliary tract of patients with Cholelithiasis increase the risk of gallstone formation
15 of the bacterial species detected in the biliary tract of patients with gallstones have publicly available genomes, and all of the species contained at least one of the genes associated with the formation of gallstones.
This study suggests that cmanipulating the microbiome could be an important part of the prevention and treatment of gallstones. Although more studies on the microbiome and Cholelithiasis are needed, it seems that prebiotics, dietary changes, fermented foods etc. could be useful in the prevention and treatment of gallstones.