EFFECT OF DEOXYCHOLATE ON IMMUNOGLOBULIN-G CONCENTRATION IN BILE - STUDIES IN HUMANS AND PIGS

Because an increase in biliary deoxycholate levels seems to be a risk factor for cholesterol gallstone formation, we determined the relation ship between deoxycholate levels and levels of the pronucleating prote in, immunoglobulin G (Ig) in human gallbladder bile. Patients with cho lesterol gallstones had a higher concentration of biliary IgG compared with a pigmented stone group and control patients. This was associate d with the simultaneous presence of two conditions in the cholesterol stone group, supersaturated bile and a high deoxycholate/cholate ratio . The other patient groups met only one of the two conditions. Next, a nimal studies were performed to determine if model biles mimicking the two conditions could affect IgG secretion by the gallbladder. Gallbla dders were exposed in vivo and then in an Ussing chamber to model bile s. The voltage clamp technique was used to monitor functional integrit y of the preparation. Three different model biles were tested: (1) tau rodeoxycholate (TDC), 80%; taurocholate (TC), 20%; and cholesterol sat uration index (CSI), 1.2; (2) TDC, 20%; TC, 80%; and CSI, 1.2; and (3) TDC, 80%; TC, 20%; and CSI, 0.6. IgG concentrations became significan tly higher in group 1 than in the other two groups. The concentration of mucous glycoprotein was also significantly greater in group 1 when compared with group 2. Plasma cells were increased in number in mucosa l and submucosal layers in group 1. We conclude that cholesterol super saturated model bile with high content of TDC induces gallbladder epit helial alterations, which increase the luminal concentration of IgG an d mucous glycoprotein.