Human Gallbladder Mucosal Function (Effects on Intraluminal Fluid and Lipid Composition in Health and Disease)

Abstract

Gallbladder mucosal absorption of fluid duringfasting is a well-known process. Indirect in vivo andrecent in vitro evidence for physiologically relevantgallbladder absorption of cholesterol and phospholipids from bile has been observed in humans. Thepresent study explored and compared by indirect meansthe relative efficiences of human gallbladder mucosalabsorption of fluid and lipids in health and disease. Biliary lipids and pigment content weremeasured in fasting gallbladder bile samples obtainedfrom gallstone-free controls and from four study groups:multiple and solitary cholesterol gallstone patients, and morbidly obese subjects with and withoutgallstones. Bile salts and pigment content weresignificantly greater in gallstone-free controls than inall other disease study groups. This was interpreted as evidence of more effective gallbladdermucosal fluid absorption in nonobese gallstone-freecontrols compared to that in all other groups.Correlation plot analyses of biliary lipids showed lowerconcentrations of phospholipids than expected from the indexbile salt concentrations. The same was found forcholesterol concentrations but only in supersaturatedsamples. These findings were much more pronounced in gallstone free-controls and were accordinglyinterpreted as evidence of more efficient gallbladderabsorption of both phospholipids and cholesterol incontrols compared with that found in each of the disease study groups. Moreover, impaired gallbladdermucosal function, while invariably associated withcholesterol gallstone disease, was not found to be anecessary consequence of the physical presence ofstones. It is concluded that efficient gallbladdermucosal absorption of both fluid and apolar lipids frombile is a normal physiological process that is oftenseriously impaired in the presence of either cholesterol gallstone disease or at least one of itsprecursor forms.