Lipid composition of bile and gallbladder mucosa in patients with acalculous cholesterolosis

To investigate pathogenetic factors of cholesterolosis of the gallbladder, the lipid composition of both the hepatic and gallbladder bile and gallbladder mucosa were compared with each other in 6 patients with and 5 patients without acalculous cholesterolosis. The molar percentage of biliary cholesterol and total bile acid pattern were similar in the two groups. Of the biliary cholesterol precursors, methyl sterols, but not squalene, correlated closely with cholesterol both in the hepatic (r = 0.901) and gallbladder bile (r = 0.747). Methyl sterols, expressed either per cholesterol or bile acids, were higher and squalene was lower in the gallbladder bile than in the hepatic bile. In addition, methyl sterols were increased in the hepatic and gallbladder bile of the patients with cholesterolosis, as if the hepatic production of these precursors had been enhanced--probably as a consequence of altered hepatic cholesterol synthesis. In cholesterolosis the gallbladder mucosa was characterized by a marked increase in triglycerides and significant elevations of the esterified sterols and free methyl sterols. The esterification degrees of sterols, which were consistently higher for methyl sterols than for cholesterol, were closely correlated with the respective mucosal sterol concentrations. The methyl sterols/cholesterol ratio in the bile correlated significantly with mucosal free and esterified methyl sterols, esterified cholesterol, and the methyl sterols/cholesterol ratio. The data suggest that free sterols can be transferred from the bile to the gallbladder mucosa, and that altered hepatic cholesterol synthesis is associated with the development of the cholesterolosis of human gallbladder.