Prediction of the bile acid composition of bile from serum bile acid analysis during gallstone dissolution therapy

Abstract

The relationship between the relative concentrations of individual bile acids in fasting serum and bile collected simultaneously was determined in 28 patients with gallstones. Seven of these patients were being treated with chenodeoxycholic acid (15 mg/kg/day). The relative concentrations of deoxycholic acid, chenodeoxycholic acid, and ursodeoxycholic acid were found to be higher in serum than in bile, while the reverse was true for cholic acid. A highly significant correlation (P < 0.001) was found between the relative proportions of each of deoxycholic acid, cholic acid, chenodeoxycholic acid and ursodeoxycholic acid in fasting serum and bile. Each correlation was defined by linear regression analysis, and regression equations were used to predict the bile acid composition of bile from the relative concentrations of the individual bile acids in serum. Although some error was obtained between predicted and actual values in individual patients, in all 7 gallstone dissolution patients treated with chenodeoxycholic acid, both the actual and predicted cholic acid concentrations in bile were < 20 moles %, and the chenodeoxycholic acid concentrations were > 70 moles %. This latter value almost always indicates biliary cholesterol unsaturation in nonobese patients. Other studies in T-tube patients confirmed that changes in biliary bile acid profiles produced by chenodeoxycholic acid treatment could be readily followed via the serum. Serum bile acid analysis is therefore a useful alternative to bile analysis for the biochemical monitoring of patients treated with chenodeoxycholic acid, and avoids duodenal intubation for bile collection.