Bile composition, microspheroliths, antinucleating activity, and gallstone calcification.

This study examined if abnormalities in bile composition and antinucleating activity are associated with gallstone calcification. Nineteen controls without gallbladder disease and 42 patients with cholesterol stones were studied. Bile was obtained at surgery and analyzed for pH and PCO2, ionized calcium, and total calcium. The pH and carbonate concentrations of gallbladder bile were significantly higher in patients with calcified stones than in patients with noncalcified stones and in controls, resulting in significantly higher levels of the ion product in patients with calcified gallstones. Microspheroliths of calcium carbonate, seen on microscopic examination of bile, predicted stone calcification with a sensitivity of 86%, a specificity of 86%, and a predictive value of 86%. Bile from control subjects completely inhibited precipitation of calcium carbonate from a supersaturated solution, whereas bile from subjects with calcified and noncalcified gallstones did not. It is concluded that gallstone calcification is related to elevated bile pH and carbonate concentrations, resulting in an elevated ion production of calcium carbonate in gallbladder bile. In addition, bile from subjects with calcified and noncalcified gallstones lacks antinucleating activity for calcium carbonate.