Gallbladder mucosal absorption of fluid during fasting is a well-known process. Indirect in vivo and recent in vitro evidence for physiologically relevant gallbladder absorption of
cholesterol and
phospholipids from bile has been observed in humans. The present study explored and compared by indirect means the relative efficiences of human gallbladder mucosal absorption of fluid and
lipids in health and disease. Biliary
lipids and pigment content were measured in fasting gallbladder bile samples obtained from
gallstone-free controls and from four study groups: multiple and solitary
cholesterol gallstone patients, and morbidly obese subjects with and without
gallstones.
Bile salts and pigment content were significantly greater in
gallstone-free controls than in all other disease study groups. This was interpreted as evidence of more effective gallbladder mucosal fluid absorption in nonobese
gallstone-free controls compared to that in all other groups. Correlation plot analyses of biliary
lipids showed lower concentrations of
phospholipids than expected from the index
bile salt concentrations. The same was found for
cholesterol concentrations but only in supersaturated samples. These findings were much more pronounced in
gallstone free-controls and were accordingly interpreted as evidence of more efficient gallbladder absorption of both
phospholipids and
cholesterol in controls compared with that found in each of the disease study groups. Moreover, impaired gallbladder mucosal function, while invariably associated with
cholesterol gallstone disease, was not found to be a necessary consequence of the physical presence of stones. It is concluded that efficient gallbladder mucosal absorption of both fluid and apolar
lipids from bile is a normal physiological process that is often seriously impaired in the presence of either
cholesterol gallstone disease or at least one of its precursor forms.