Cholesterol nucleation-influencing activity in t-tube bile

Abstract

Nucleation-influencing activity was determined in T-tube bile samples derived from patients with obstructive jaundice. Since native T-tube bile samples do not nucleate, nucleation-influencing activity was determined by measuring the influence of T-tube bile on the nucleation time of model bile. In the assay, T-tube bile was mixed with model bile, and the nucleation time of this mixture was compared with the nucleation time of a model bile supplemented with the same amount of lipid as present in the bile sample. The results were expressed as ratio of the nucleation time of the mixture and the nucleation time of the control (NTm/NTc). There was a significant difference (p less than 0.01) between bile samples from patients with cholesterol gallstones and samples from patients with biliary obstruction due to other causes. More than 80% of the 33 samples from eight patients with stones were nucleation-promoting (NTm/NTc less than or equal to 0.6). Of the 40 bile samples from patients without stones, 7 were nucleation-promoting, 25 had no effect (NTm/NTc = 0.8 to 1.2) and 8 bile samples were nucleation-inhibiting (NTm/NTc greater than or equal to 1.4). There was no correlation between the lipid or protein content of a T-tube bile sample and its nucleation-influencing activity. The presence of both nucleation-promoting and nucleation-inhibiting activity in the same T-tube bile was demonstrated by chromatography on concanavalin A-Sepharose. More than 75% of the biliary protein did not bind to the column. This fraction showed nucleation-inhibiting activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Fucosylation of N-Glycans Regulates the Secretion of Hepatic Glycoproteins into Bile Ducts

“…It was reported that human bile contains several cholesterol crystallization-promoting glycoproteins and that biliary Hp and AGP have highly potent cholesterol crystallization-promoting activity at physiological concentrations (29,30). However, these promoters were identified from a ConA-bound fraction (31), and a correlation of its activity with fucosylation of glycoproteins has not been reported. Further studies will be required to determine whether fucosylated oligosaccharides on glycoproteins are associated with biological functions in bile as well as intracellular traffic in hepatocytes.…”

Carcinoembryonic antigen-related cell adhesion molecule 1 is the 85-kilodalton pronase-resistant biliary glycoprotein in the cholesterol crystallization promoting low density protein-lipid complex

“…CABF was isolated from human T-tube bile by lectin affinity chromatography, as described by Groen et al 15 A 2-mL aliquot of CABF was incubated with 2 mg/mL pronase for 48 hours at 37°C.…”

“…The major cholesterol crystallization promoting activity (CCPA) was localized to the Concanavalin A-binding fraction of biliary glycoproteins (CABF). [15][16][17][18] Groen et al 15 showed the CCPA of CABF to be pronase resistant and specific for biliary glycoproteins. This concept was supported by the observation of Pattinson and Willis 19 that the kinetics of cholesterol crystallization in bile was unaffected to digestion with pronase, even though pronase destroyed all biliary proteins visible on SDS-PAGE.…”

Cholesterol crystallization in human gallbladder bile: Relation to gallstone number, bile composition, and apolipoprotein E4 isoform

“…4 Several factors may contribute to fast crystallization, such as biliary cholesterol supersaturation, increased concentration of bile in the gallbladder, 2,5 increased amounts of the hydrophobic bile salt deoxycholate, 6 a shortage of crystallizationinhibiting proteins, 7 or excessive crystallization promoting proteins. 8 The crystallization-promoting proteins have been partly isolated by means of lectin chromatography with concanavalin A-Sepharose. 8 This lectin binds glucose-and mannose-containing glycoproteins, which comprise about 10% of total biliary proteins.…”

“…8 The crystallization-promoting proteins have been partly isolated by means of lectin chromatography with concanavalin A-Sepharose. 8 This lectin binds glucose-and mannose-containing glycoproteins, which comprise about 10% of total biliary proteins. Increased total protein concentration has been associated with faster cholesterol crystallization [9][10][11] and various concanavalin A-binding proteins such as immunoglobulins (Igs), 12,13 ␣1 acid glycoprotein, 14 haptoglobin, 15 and aminopeptidase-N 8,16 promote crystallization in in vitro systems.…”