Gallbladder emptying in vivo, bile composition, and nucleation of cholesterol crystals in patients with cholesterol gallstones

Impaired postprandial gallbladder emptying may provide time for progressive bile concentration with formation of instable cholesterol-rich vesicles and fast nucleation of cholesterol crystals. The aim of this study was to assess postprandial gallbladder emptying, bile composition, and nucleation of cholesterol crystals in the same patient. In 30 patients with cholesterol gallstones, postprandial gallbladder emptying was measured ultrasonographically. In each patient, gallbladder bile composition (obtained at cholecystectomy) and nucleation of cholesterol crystals was determined. Patients were divided in 22 strong contractors (>50% postprandial gallbladder emptying) and 8 weak contractors. In weak contractors, bile salt and phospholipid concentrations were much higher than in strong contractors ( and , respectively). Cholesterol concentrations were comparable in strong and weak contractors. Consequently, total lipid concentration was significantly higher (15.5 ± 1.4 and 9.2 ± 0.7 g/dL; P < 0.001) and cholesterol saturation index significantly lower (0.90 ± 0.08 and 1.61 ± 0.17; P < 0.001) in weak contractors. Nucleation time, percentage of cholesterol in vesicles, bile salt species, and molecular species of phosphatidylcholine were not significantly different. Differences in bile composition can be linked to different patterns of post-prandial gallbladder emptying and may point to two different pathways of gallstone formation.