Transport of fluid and biliary lipids in the canine gallbladder in experimental cholecystitis

In acute cholecystitis the cystic duct is usually obstructed by a gallstone and the gallbladder is often tensely distended with clear fluid. Because these findings suggest that fluid absorption in the gallbladder may be reversed in cholecystitis, we examined the effect of inflammation on the gallbladder mucosal function in dogs. In 20 dogs cholecystitis was induced by ligating the cystic duct and allowing inflammation to develop from bile stasis and the presence of a chronic indwelling cannula in the gallbladder. Every morning an aliquot of normal hepatic bile was infused into the gallbladder through a cannula in the gallbladder fundus. After either 4 or 24 hr the gallbladder contents were aspirated, the volume was measured, and the concentrations of bile acids, cholesterol, phospholipids, and protein were determined. Changes in volume were checked using [14C]PEG as a nonabsorbable tracer. A net absorption of fluid, bile acids, cholesterol, and phospholipids occurred during the first 24 to 48 hr after ligation of the cystic duct. Thereafter, fluid, cholesterol, and protein were secreted into the lumen, but absorption of bile acids continued. The lithogenic index of bile placed in the inflamed gallbladder was always greater when the bile was removed 24 hr later. The rate of fluid secretion into the lumen of the inflamed gallbladder increased after a meal and decreased after indomethacin. These findings demonstrate that inflammation can stimulate the gallbladder mucosa to secrete fluid, a process that may be important in the pathophysiology of acute cholecystitis in man. Since inflammation also resulted in an increased cholesterol saturation of gallbladder bile, cholecystitis per se may contribute to the formation of cholesterol gallstones.