Urinary Elimination of Bile Acid Glucuronides under Severe Cholestatic Situations: Contribution of Hepatic and Renal Glucuronidation Reactions

Figure 2

While bile flow restoration modulates metabolic ratios of bile acid glucuronides in a glucuronide- and fluid-dependent manner ((a) and (b)), the CA-24G/CA ratio is unique in being significantly associated with serum and urine (c–e). Serum and urine samples drawn before and after endoscopic biliary stenting from patients with stenosed bile ducts were analyzed for their concentrations in 11 bile acid-glucuronide species using LC-MS/MS. Concentrations of unconjugated acids were determined as reported [20], and the metabolic ratio for each species (a) was calculated as the ratio of glucuronide versus unconjugated precursor. (b) Black (serum; ) and white (urine; ) bars represent the mean ± SEM of fold changes (posttreatment values divided by pretreatment values) in MRs. Statistically significant differences between prestenting versus poststenting samples were determined using the Wilcoxon matched-pairs signed-rank test: ; . Other changes failed to reach statistical significance. The absence of unconjugated LCA in urine impaired such analysis for LCA-3 and -24G [20], while urine HDCA-24G/HDCA was null. (c–e) Correlation analyses of paired () prestenting (c) and poststenting (d) serum and urine CA-24G/CA values or response to stenting determined as the difference between post- and pretreatment levels (e) were performed using the Spearman rank-order correlation (), and values for comparisons are indicated.

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