The effect of ursodeoxycholic acid on nucleation time in patients with solitary or multiple gallbladder stones.

The objective of this study was to determine the effect of ursodeoxycholic acid (UDCA), 1000 mg/day, on nucleation time and cholesterol saturation index (CSI) in human gallbladder bile.In 48 patients with cholesterol gallbladder stones undergoing extracorporeal shockwave lithotripsy, bile samples exhibited a significant longer median nucleation time in the case of solitary stones (7.9 +/- 5.1 days) than in patients with multiple stones (1.7 +/- 1.0 days; p < 0.0001). Stone number and nucleation time were correlated inversely (r = -0.79). UDCA led to a significant prolongation of nucleation time (solitary stones 17.9 +/- 5.8 days, multiple stones 18.0 +/- 5.7 days; p < 0.01) with a concomitant disappearance of cholesterol liquid crystals and cholesterol monohydrate crystals in gallbladder bile. Initially, there was no difference in the CSI between patients with solitary stones or multiple gallbladder stones (1.4 +/- 0.3 vs. 1.4 +/- 0.4, respectively). UDCA caused a significant decrease in CSI by 64.3% (p < 0.01).We conclude that UDCA prolongs the nucleation time by decreasing the cholesterol saturation index, as well as by diminishing cholesterol liquid crystals and cholesterol monohydrate crystals in gallbladder bile from patients with cholesterol gallstones. Second, recurrent stones essentially occur in patients with multiple cholesterol gallstones, reflected by a concomitant short nucleation time.