Current concepts of the pathogenesis of cholesterol gallstones

Changes in gallbladder motor function during the female cycle--a risk factor leading to gallstone formation?

The gallbladder volume of eight women with stable cycles was determined by sonography. Furthermore, gallbladder contraction--following an orally administered fatty meal and the spontaneous refilling of the empty gallbladder--was quantitatively examined. The formula of a rotation ellipsoid, which has been proven to be adequately accurate in in vitro studies, was used for calculating the gallbladder volume. In the gestagen phase (21st or 22nd day) the intraindividual studies showed greater fasting volumes, higher residual volumes after contraction, slower gallbladder emptying, and retarded refilling of the empty gallbladder as compared to the estrogen phase (12th or 13th day). The hormonally modified contraction behavior and the differing course of gallbladder filling may play a major role in the pathogenesis of gallstone formation.

Biliary pigment and cholesterol calculi in patients with and without juxtapapillary duodenal diverticula

The occurrence of pigment and cholesterol calculi was studied in 45 patients with concrements in the gallbladder but no calculi in the common or intrahepatic bile ducts. Twenty-one of the patients had juxtapapillary duodenal diverticula diagnosed by duodenoscopy. Twenty-four patients had no diverticula. The classification of the calculi as pigment stones or cholesterol stones was based on quantitative determination of the cholesterol contents. Calculi with a cholesterol content of less than 25% were classified as pigment stones; calculi with a cholesterol content of more than 25% were classified as cholesterol stones. All pigment stones had a cholesterol content of less than 20%. With the exception of four patients the cholesterol content was over 70% in all cholesterol stones. Twelve of the 21 patients with were classified as pigment stones; calculi with a cholesterol content of more than 25% were classified as cholesterol stones. All pigment stones had a cholesterol content of less than 20%. With the exception of four patients the cholesterol content was over 70% in all cholesterol stones. Twelve of the 21 patients with were classified as pigment stones; calculi with a cholesterol content of more than 25% were classified as cholesterol stones. All pigment stones had a cholesterol content of less than 20%. With the exception of four patients the cholesterol content was over 70% in all cholesterol stones. Twelve of the 21 patients with diverticula had pigment stones, whereas only 1 of the 24 patients without diverticula had pigment calculi, a difference that was statistically significant (p less than 0.01).

Multicompartmental analysis of cholesterol metabolism in man. Characterization of the hepatic bile acid and biliary cholesterol precursor sites

The present report has presented the first clear evidence in man for the existence of specific hepatic cholesterol precursor sites associated with the formation and secretion of bile acids and biliary cholesterol. These hepatic compartments derive virtually all their cholesterol from newly synthesized and lipoprotein free cholesterol. The model which is presented was formulated on current concepts of cholesterol metabolism in man and is concerned, at this initial stage, with the elucidation of the bile acid and biliary cholesterol compartments. The complexity of cholesterol metabolism in man necessitated an initial approach that would minimize the number of inputs of cholesterol into the system, allow for the sampling of several cholesterol compartments, and permit the simultaneous labeling of newly synthesized cholesterol and preformed cholesterol. To achieve these objectives, we studied the patient with a total bile fistula. Six patients were administered simultaneously pulse injections of labeled mevalonic acid and [(14)C]cholesterol. The qualitative features of the specific activity time course curves after labeled mevalonic acid revealed no precursor-product relationship between bile acid, biliary cholesterol, and plasma free cholesterol. The peak specific activity of the bile acids was reached in approximately 100 min and was higher than the biliary cholesterol, which was higher than the plasma free cholesterol. The plasma free cholesterol specific activity became higher than the other lipids after 12 h and remained higher throughout the period of study. Similar related observations were made with [(14)C]cholesterol. The data were then subjected to simulation analysis and modeling using the SAAM-27 computer program. Computer least-square fits of the data were obtained after the model was evolved. During the model development, the least number of compartments and transport pathways were introduced consistent with a good fit of the data. Of particular importance was the constraint that the model fit the data obtained from both [(14)C]cholesterol and labeled mevalonic acid. The same parameter values were used to fit the data from both tracers. The fluxes arrived at in the model indicate that 31% and 20%, respectively, of the cholesterol input into the bile acid and biliary cholesterol precursor sites were derived directly from the newly synthesized hepatic cholesterol. The remainder had its origin predominantly from lipoprotein free cholesterol. Plasma esterified cholesterol (as free) made a small contribution (11%) to the bile acid compartment. Similarly, 10% of the biliary cholesterol arose from an unknown hepatic site. The present report has provided the basis for a new procedure for studying in vivo cholesterol metabolism in man. Examination of the derived cholesterol flux rates between the compartments suggests the presence of an important mechanism regulating the partitioning of lipoprotein free cholesterol between the bile acid and biliary cholesterol precursor sites. Aberrations in the proportioning of precursor cholesterol between these sites could be a causative factor precipitating the excessive secretion of biliary cholesterol and the production of lithogenic bile.

Comparison of linoleic acid and stearic acid absorption by the gallbladder

The absorption of [14C]linoleic acid and [14C]stearic acid in guinea pig bile by the in situ guinea pig gallbladder was compared. Linoleic acid was adsorbed at a faster rate than was stearic acid. Differences were also observed in the incorporation of these two fatty acids into complex lipids of the gallbladder mucosa. A greater portion of adsorbed linoleic acid was incorporated into triacylglycerol whereas a greater portion of stearic acid was incorporated into sphingomyelin. The significance of these findings in relation to the fatty acid composition of bile is discussed.