Increased biliary lipid secretion in celiac disease.

Direct measurements of biliary lipid outputs, cholesterol absorption, and fecal steroids were carried out in celiac patients before and during a gluten-free diet to show whether an enhanced flux of cholesterol into the gut (found earlier in these patients) is due to increased biliary output or mucosal secretion of cholesterol, or both. The bile flow rate and the secretion of biliary cholesterol, phospholipids, and bile acids were significantly increased in celiac disease and appeared to be normalized by effective gluten-free diet. A significant amount of cholesterol originated from the intestinal mucosa, but the amount was not consistently increased in the celiac patients. Fractional absorption of cholesterol was low, but due to enhanced biliary secretion the amount of cholesterol absorbed was mostly within the normal limits so that fecal neutral steroids of biliary origin and cholesterol synthesis were markedly increased in celiac disease. Despite high biliary bile acid secretion, fractional absorption of bile acids was enhanced. Thus, the effective ileal conservation of bile acids could have contributed to increased bile acid-dependent secretion of biliary cholesterol. The enhanced biliary and fecal output of cholesterol should ultimately be balanced by augmented cholesterol synthesis, but the closer site of the synthesis and regulatory mechanisms between cholesterol and lipoprotein metabolism need further exploration.