Disorders of bile acid metabolism in cholesterol gallstone disease

Abstract

The aim of the study was to evaluate the metabolism of individual bile acids in patients with cholesterol gallstone disease. Therefore, we determined pool size and turnover of deoxycholic (DCA), cholic (CA), and chenodeoxycholic acid (CDCA) in 23 female gallstone patients classified according to their gallbladder function and in 15 healthy female controls. Gallstone patients had normal hepatic bile acid synthesis, but, depending on gallbladder function, differed with respect to turnover and size of the bile acid pools: Patients with well-emptying gallbladder (group A, n = 9) had enhanced turnover and reduced pools of CA (-46%; P < 0.01 vs. controls) and CDCA (-24%; P < 0.05), but normal input and size of the DCA pool. With reduced gallbladder emptying (< 50% of volume; group B, n = 6), turnover and pools of CA, CDCA, and DCA were similar as in controls. Patients with loss of gallbladder reservoir ( group C, n = 8) had increased input (+100%; P < 0.01) and pool size of DCA (+45%; P = 0.07) caused by rapid conversion of CA to DCA, while the pools of CA (-71%; P < 0.001 vs. controls) and CDCA (-36%; P < 0.05) were reduced by enhanced turnover. Thus, in patients with cholesterol gallstones, the pools of primary bile acids are diminished, unless gallbladder emptying is reduced. Furthermore, in a subgroup of gallstone patients, who had completely lost gallbladder function, the CA pool is largely replaced by DCA owing to rapid transfer of CA to the DCA pool. This probably contributes to supersaturation of bile with cholesterol.