High protein and total lipid concentration are associated with reduced metastability of bile in an early stage of cholesterol gallstone formation.

Previous studies from this laboratory suggested that high gallbladder protein concentrations as well as excessive dehydration of bile might reduce the normal metastability of human gallbladder bile. This study attempted to identify persons in an early stage of stone formation, when there are crystals but no stones, and to determine the composition of bile under these conditions of reduced metastability. Two hundred twenty-seven patients were studied, 96 without gallstones. Twenty-three of 96 control patients had cholesterol crystals in their bile. Total protein concentration, total lipid concentration, and cholesterol saturation index were greater in control patients with crystals in bile. To determine whether or not cholesterol saturation index alone could account for the presence of crystals, control patients with cholesterol saturation index above the median value of 1.04 were studied. In this case there was no difference in cholesterol saturation index between the 19 crystal-positive (1.27) and 29 crystal-negative patients (1.26), but the difference in total protein and lipid concentrations persisted. Total protein and total lipid concentrations were even higher in crystal-positive sediments containing large numbers of crystals. Sludge seen by ultrasonography was more common in patients with crystal-positive sediments. High protein and lipid concentrations are associated with reduced metastability of bile.