Effect and mechanism of endoclip papilloplasty in reducing the incidence of cholelithiasis.

BACKGROUND

Endoscopic sphincterotomy (EST) is widely used to treat common bile duct stones (CBDS); however, long-term studies have revealed the increasing incidence of recurrent CBDS after EST. Loss of sphincter of Oddi function after EST was the main cause of recurrent CBDS. Reparation of the sphincter of Oddi is therefore crucial. This study aims to investigate the effectiveness and safety of endoclip papilloplasty (ECPP) for repairing the sphincter of Oddi and elucidate its mechanism.

METHODS

Eight healthy Bama minipigs were randomly divided into the EST group and the ECPP group at a 1:1 ratio, and bile samples were collected before endoscopy and 6 months later. All minipigs underwent transabdominal biliary ultrasonography for the diagnosis of cholelithiasis 6 months after endoscopy. The biliary microbiota composition and alpha and beta diversity were analyzed by 16S ribosomal RNA gene sequencing. Differential metabolites were analyzed by bile acid metabolomics to explore the predictive indicators of cholelithiasis.

RESULTS

Three minipigs were diagnosed with cholelithiasis in the EST group, while none in the ECPP group showed cholelithiasis. The biliary Firmicutes/Bacteroidota (F/B) ratio was increased after EST and decreased after ECPP. The Chao1 and observed species index significantly decreased 6 months after EST ( P  = 0.017 and 0.018, respectively); however, the biliary α-diversity was similar before and 6 months after ECPP. The β-diversity significantly differed in the EST group before and 6 months after EST, as well as in the ECPP group before and 6 months after ECPP (analysis of similarities [ANOSIM]: R  = 0.917, P  = 0.040; R  = 0.740, P  = 0.035; respectively). Glycolithocholic acid (GLCA) and taurolithocholic acid (TLCA) accumulated in bile 6 months after EST.

CONCLUSIONS

ECPP has less impact on the biliary microenvironment than EST and prevents duodenobiliary reflux by repairing the sphincter of Oddi. The bile levels of GLCA and TLCA may be used to predict the risk of cholelithiasis.