Biliary lipid composition in patients with cholesterol and pigment gallstones and gallstone-free subjects: deoxycholic acid does not contribute to formation of cholesterol gallstones.

Abstract

Four main disturbances have been attributed to cholesterol gallstone disease: hypersecretion of cholesterol from the liver with cholesterol supersaturation in bile; disturbed motility with defective absorption and secretion by the gallbladder; increased crystallisation of cholesterol in the gallbladder bile; and slow intestinal transit with increased amount of deoxycholic acid in the bile acid pool. We aimed to evaluate the biliary lipid composition in a large series of gallstone patients, with emphasis on the amount of deoxycholic acid and with respect to number of stones, compared to gallstone free subjects. Bile was sampled during operations through puncture of the gallbladder from 145 cholesterol gallstone patients, 23 patients with pigment stones and 87 gallstone free patients undergoing cholecystectomy. Biliary lipid composition, cholesterol saturation, bile acid composition, nucleation time and cholesterol crystals were analysed. The patients with cholesterol gallstones showed higher molar percentage of cholesterol, lower total biliary lipid concentration, higher cholesterol saturation, shorter nucleation time and higher proportion of crystals in bile than the other groups. The nucleation time was significantly shorter in multiple cholesterol gallstone patients, but this was not due to higher cholesterol saturation. Male cholesterol gallstone patients showed higher cholesterol levels, lower total biliary lipid concentration, and higher cholesterol saturation in bile than female patients. There was no difference in biliary content of deoxycholic acid, but significantly lower content of cholic acid in gallstone patients compared to gallstone free patients. We conclude that deoxycholic acid does not contribute to gallstone formation in cholesterol gallstone patients. The short nucleation time in patients with multiple cholesterol stones is not due to higher cholesterol saturation.