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

Background Four main disturbances have been attributed to cholesterol galls tone 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 t he gallbladder bile; and slow intestinal transit with increased amount of d eoxycholic acid in the bile acid pool. We aimed to evaluate the biliary lip id composition in a large series of gallstone patients, with emphasis on th e amount of deoxycholic acid and with respect to number of stones, compared to gallstone free subjects. Materials and methods Bile was sampled during operations through puncture o f 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, n ucleation time and cholesterol crystals were analysed. Findings The patients with cholesterol gallstones showed higher molar perce ntage of cholesterol, lower total biliary lipid concentration, higher chole sterol saturation, shorter nucleation time and higher proportion of crystal s in bile than the other groups. The nucleation time was significantly shor ter in multiple cholesterol gallstone patients, but this was not due to hig her cholesterol saturation. Male cholesterol gallstone patients showed high er cholesterol levels, lower total biliary lipid concentration, and higher cholesterol saturation in bile than female patients. There was no differenc e in biliary content of deoxycholic acid, but significantly lower content o f cholic acid in gallstone patients compared to gallstone free patients. Conclusions We conclude that deoxycholic acid does not contribute to gallst one formation in cholesterol gallstone patients. The short nucleation time in patients with multiple cholesterol stones is not due to higher cholester ol saturation.