Die Bedeutung von Muzin-Glykoprotein in der Pathogenese der Cholezystolithiasis

OBJECTIVES: Mucin is supposed to accelerate the crystallization of
cholesterol in model bile while studies in native human gallbladder
bile revealed conflicting results. METHODS: Therefore, we
determined the relation of mucin concentration and cholesterol
crystal observation time in gallbladder bile of 73 patients with
cholesterol and mixed and 21 patients with pigment stones. In
addition, bile samples of 20 patients with cholesterol gallstones
were supplemented with either 0 (control) or 0.5-4.0 mg/ml purified
bovine mucin or human mucin isolated from gallbladder bile, to
study the effect of variable mucin concentrations on the
crystallization of cholesterol. RESULTS: Rapid nucleating biles (=
4 days, n = 59) showed higher mucin concentrations (0.73 +/- 0.1
mg/ml vs 0.43 +/- 0.07 mg/ml) than biles with longer (> 4 days,
n = 35) cholesterol crystal observation times (P < 0.05), but no
correlation between mucin concentration and cholesterol crystal
observation time was observed. Supplementation experiments with
bovine purified mucin (up to 4.0 mg/ml) showed no significant
effect on the total amount of newly formed cholesterol crystals
within 21 days. However, higher amounts of newly formed cholesterol
crystals were seen in bile samples supplemented with human mucin in
comparison to negative controls. CONCLUSIONS: Our results
demonstrate a dose-dependent effect of human but not of bovine
gallbladder mucin on the formation of cholesterol monohydrate
crystals in gallbladder bile of patients with cholesterol stones.
Therefore, studies of cholesterol crystallization in model bile
systems may be valuable but should always be confirmed in native
gallbladder bile as the more physiological effector system.