Biliary Mucin Research Articles

Effect of Nicotine on Gallbladder Bile

Several studies have shown that symptomatic gallstones are largely a disease of nonsmokers, which raises the possibility that nicotine may protect against the formation of gallstones. To examine the effect of nicotine on the gallbladder, 32 rabbits were allocated to four groups: controls and three treatment groups in which nicotine tartarate at low, medium and high doses was administered subcutaneously via an osmotic minipump. After 14 days’ treatment the gallbladder was removed and measurements made of gallbladder mucin synthesis, bile mucin concentration, bile acid concentration and cholesterol saturation. Serum nicotine concentrations (ng/mL) were (± SE) 0.4±0.1, 3.5±0.4, 8.8±0.8 and 16.2±1.8 in the controls and three treatment groups, respectively. Total bile acid concentration increased significantly in all three treated groups with the greatest increase in the group given low dose nicotine (P<0.001). Cholesterol saturation did not differ significantly in any group but soluble mucin concentration in gallbladder bile was significantly reduced (P=0.013, 95% CI: 16 to 111) with high dose nicotine. Gallbladder mucin synthesis, measured by3H-glucosamine incorporation, did not change significantly with nicotine treatment. Subcutaneous nicotine 2.0 mg/kg/day for 14 days significantly reduced the concentration of biliary mucin, which could potentially reduce cholesterol nucleation and subsequent gallstone formation. This may be one of the mechanisms responsible for the relative reduction in gallstone disease among smokers.

Isolation of mucin from human hepatic bile and its induced effects on precipitation of cholesterol and calcium carbonatein vitro

Biliary mucin was isolated from human hepatic bile, and its induced effects on the appearance time of cholesterol monohydrate crystals (nucleation time) and on the precipitation of calcium carbonate were studied in vitro to examine the possible significance of mucin for ductular gallstone formation. Mucin was isolated by gel filtration on Sepharose CL-4B and a subsequent CsCl density gradient ultracentrifugation. Mucin thus obtained had a high purity as shown by a high-molecular-weight band on SDS-polyacrylamide gel electrophoresis and by the compatible amino acid composition with mucin purified from the gallbladder. The mucin at as low a concentration as 100 micrograms/ml significantly shortened the cholesterol nucleation time in the supersaturated model bile, mimicking human hepatic bile. On the other hand, the addition of mucin inhibited calcium carbonate precipitation in vitro. Taking account of that both cholesterol and calcium salts are major constituents of ductular gallstones, we conclude that biliary mucin is likely to play an important regulating role in the formation of ductular stones.

Stabilization of biliary lipid particles by ursodeoxycholic acid. Prolonged nucleation time in human gallbladder bile.

We evaluated the effect of ursodeoxycholic acid on the metastability of human bile as reflected by nucleation time and also assessed the mechanism of its action in an ultrastructural study. Ursodeoxycholic acid significantly prolonged the nucleation time of gallbladder bile from cholesterol gallstone patients without causing either drastic changes in the distribution of cholesterol between the nonmicellar and micellar fractions of bile or biliary cholesterol desaturation. Gel permeation chromatography resolved two distinct components of the nonmicellar fraction: vesicles and phospholipid lamellae (identified by electron microscopy). Nonmicellar cholesterol was predominantly carried by vesicles in the bile of untreated gallstone patients, whereas it was chiefly carried by phospholipid lamellae in patients treated with ursodeoxycholic acid. Furthermore, phospholipid lamellae from untreated gallstone patients showed rapid transformation and cholesterol microcrystal formation within seven days, whereas the lamellae from ursodeoxycholic acid-treated patients were stabilized and showed little change. On the other hand, biliary mucin concentration was reduced by the treatment with ursodeoxycholic acid. These findings suggest that ursodeoxycholic acid stabilizes phospholipid lamellae and consequently prolongs nucleation time. It is also possible that the reduction of biliary mucin plays a role in this process.

Characterization of mucin in the hepatic bile of patients with intrahepatic pigment stones.

To investigate the relationship between biliary mucin and ductular stone formation, mucin was isolated from hepatic bile using gel filtration on Sepharose CL-4B. The bile was obtained from 14 patients with stones in various sites of the biliary tract. The hexose content in the excluded fraction was significantly higher in patients with intrahepatic ductular stones (68.7 +/- 20.5 micrograms/mL; mean +/- s.d.) than in those with gall-bladder stones or extrahepatic ductular stones (23.8 +/- 8.1 micrograms/mL, 33.3 +/- 9.5 micrograms/mL; P less than 0.05), suggesting a higher concentration of mucin in the bile of patients with intrahepatic ductular stones. Ion-exchange chromatography on DEAE-Sephacel showed that most mucin from each material was negatively charged and electrophoretic studies indicated that it was composed mainly of high molecular weight (greater than 10(6)), sulfated glycoprotein. These results suggested that the mucin content of hepatic bile might have an important relation to the development of intrahepatic ductular stones.

Biliary Sludge and Microcalculi in Intrahepatic Bile Ducts

To clarify the morphology and pathogenesis of intrahepatic calculi in the incipient stage, we examined biliary sludge and microcalculi in intrahepatic bile ducts by morphologic and X-ray microanalytical methods in 18 (1.5%) among 1,179 autopsied livers. The hepatobiliary conditions of these 18 livers were intra- and extrahepatic biliary obstruction in 14 cases, hepatic fibrosis in three cases, and cirrhosis with hepatocellular carcinoma in the remaining one. Grossly, brown-pigmented microcalculi were observed floating in biliary sludge. Microscopically, the biliary sludge was composed of mucin, fibrinous materials, desquamated epithelial cells and a few bilirubin granules. The microcalculi were embedded in the sludge and consisted of mucin and precipitates of bilirubin with a granular, lamellar or amorphous appearance. Bacterial colonies were recognized in both the sludge and microcalculi in all but three cases. Intrahepatic bile ducts harboring sludge and microcalculi showed a minimal to moderate degree of glandular proliferation with mucin production. X-ray microanalysis disclosed that the sludge contained little calcium ion, whereas microcalculi were calcium-rich. These findings suggest that biliary obstruction, bacterial infection and mucin hypersecretion play an important role in the formation of intrahepatic biliary sludge and microcalculi, and that sludge is causally related to the formation of intrahepatic microcalculi. Intrahepatic microcalculi and biliary sludge may represent a pathogenetic sequence in the early stage of calcium bilirubinate hepatolithiasis.

ヒト胆汁ムチンの精製,性状および肝疾患における血中濃度

ヒト胆汁ムチンの精製,性状および肝疾患における血中濃度

Pigment gallstone disease.

Black and brown pigment gallstones are morphologically, compositionally, and clinically distinct. Black stones form primarily in the gallbladder in sterile bile and are associated with advanced age, chronic hemolysis, alcoholism, cirrhosis, pancreatitis, and total parenteral nutrition. Brown stones form not only within the gallbladder but also within the intrahepatic and extrahepatic ducts; they are uniformly infected with enteric bacteria and are usually associated with ascending cholangitis. Brown stones are related to juxtapapillary duodenal diverticula and are the predominant type of de novo common bile duct stones. Cholecystectomy is usually curative in black pigment stone disease, whereas stones often recur after cholecystectomy for brown stone disease. The pathogenesis of black stones is probably related to nonbacterial, nonenzymatic hydrolysis of bilirubin conjugates. At the pH of bile, this results in two monohydrogenated bilirubin anions that precipitate with calcium ions. Bilirubin monoconjugates that are increased in several conditions, such as Gilbert's syndrome and chronic hemolysis, may play a pivotal role in black stone formation as a source of unconjugated monohydrogenated bilirubin and as a possible co-precipitant with calcium. The precipitation of calcium carbonate and phosphate is influenced by local gallbladder factors. Brown pigment stones are formed in bile infected with enteric bacteria that elaborate hydrolytic enzymes: beta-glucuronidase, phospholipase A, and conjugated bile acid hydrolase. The resulting anions of bilirubin and fatty acids form insoluble calcium salts. We used nb/nb mice with a chronic hemolytic anemia as a model of hemolysis-induced black stone disease. The presence of 40% bilirubin monoconjugates in mouse gallstones indicated the importance of this moiety in the pathogenesis of black stones. Other data obtained by marrow transplantation experiments in mice revealed the relative importance of genotype versus the hemolytic anemia on determinants such as biliary bile acid composition and mucin secretory glands in the mouse gallbladder neck. Additional physical chemical studies of the interaction of unconjugated bilirubin in model bile solutions will be helpful in further delineating the pathogenesis of both black and brown pigment gallstones.

The histochemistry of biliary mucins and the changes caused by infestation with Clonorchis sinensis.

The histochemistry of biliary mucins and the changes caused by infestation with Clonorchis sinensis.