Role of High total protein in gallbladder bile in the formation of cholesterol gallstones.

While it is generally accepted that cholesterol supersaturation of
bile is of key importance in the rapid formation of cholesterol
crystals, the role of total biliary protein and pH in the
pathogenesis of cholesterol gallstones is less well understood. The
relation of cholesterol saturation, total protein, and pH was
studied in 73 gallbladder bile samples with and 35 gallbladder bile
samples without cholesterol crystals. In samples containing
crystals, a trend to higher values of cholesterol and to a higher
cholesterol saturation index was observed. However, significantly
(P = 0.02) higher concentrations of total protein were found in
samples with crystals [0.80 +/- 0.40 g/dL (8.0 +/- 4.0 g/L)] than
in samples without crystals [0.63 +/- 0.26 g/dL (6.3 +/- 2.6 g/L)].
Moreover, of 22 bile samples with total protein concentrations
greater than 10.0 g/L, cholesterol crystals were detected in all
but 2. Total lipids, bile acids, phospholipids, and pH values were
not significantly different in the two groups of bile samples. It
was concluded that high biliary protein concentrations are
frequently associated with cholesterol crystals and may, therefore,
be a possible risk factor in the pathogenesis of cholesterol
gallstones.