Circulating fasting total BA was not associated with obesity .
FGF19 was inversely and faecal BA excretion was positively associated with obesity .
Roux-en-Y gastric bypass ( RYGB ) and sleeve gastrectomy ( SG )  modulated BA metabolism , ie , increased BA and FGF19 .
Our results indicate that BA metabolism is altered in obesity .
Increased glycine-amidated hyocholic acid correlates to improved early weight loss after sleeve gastrectomy
Background Bile acids ( BAs ) are post-pr and ial hormones that play an important role in glucose and lipid homeostasis as well as energy expenditure . Total and glycine-ami date d BAs increase after sleeve gastrectomy ( SG ) and correlate to improved metabolic disease . No specific bile acid subtype has been shown conclusively to mediate the weight loss effect . Therefore , the objective of this study was to prospect ively evaluate the comprehensive changes in meal-stimulated BAs after SG and determine if a specific change in the BA profile correlates to the early weight loss response . Methods Patients were prospect ively enrolled at the University of Nebraska Medical Center who were undergoing a SG for treatment of morbid obesity . Primary and secondary plasma bile acids and their ami date d ( glycine , G- , or taurine , T- ) subtypes were measured at fasting , 30 and 60 min after a liquid meal performed pre-op , and at 6 and 12 weeks post-op . Area under the curve ( AUC ) was calculated for the hour meal test for each bile acid subtype . BAs that were significantly increased post-op were correlated to body mass index ( BMI ) loss . Results Total BA AUC was significantly increased at 6 ( p < 0.01 ) and 12 weeks post-op ( p < 0.01 ) compared to pre-operative values . The increase in total BA AUC was due to a statistically significant increase in G-BAs . Nine different BA AUC subtypes were significantly increased at both 6 and 12 weeks post-op . Increased total and G-chenodeoxycholic acid AUC was significantly correlated to the 6 week BMI loss ( p = 0.03 ) . Increased G-hyocholic acid was significantly correlated to increased weight loss at both 6 ( p = 0.05 ) and 12 weeks ( p = 0.006 ) . Conclusions SG induced an early and persistent post-pr and ial surge in multiple bile acid subtypes . Increased G-hyocholic consistently correlated with greater early BMI loss . This study provides evidence for a role of BAs in the surgical weight loss response after SG
Circulating fasting total BA was not associated with obesity .
FGF19 was inversely and faecal BA excretion was positively associated with obesity .
Roux-en-Y gastric bypass ( RYGB ) and sleeve gastrectomy ( SG )  modulated BA metabolism , ie , increased BA and FGF19 .
Our results indicate that BA metabolism is altered in obesity .