Effects of bile salt and phospholipid hydrophobicity on lithogenicity of human gallbladder bile

Increased biliary bile salt and phospholipid hydrophobicity may promote nucleation of cholesterol crystals and gallstone formation. We therefore compared bile salt composition (determined by gas-liquid chromatography) in patients with cholesterol (n = 35) and pigment (n = 16) gallstones (group A). Bile salt composition and cumulative bile salt hydrophobicity index were not different between both stone types. Hydrophobicity index or % of individual bile salts did not correlate with cholesterol saturation index or nucleation time. In an additional 21 cholesterol stone patients (group B) biliary bile salt and phospholipid hydrophobicity as determined by high-pressure liquid chromatography did not correlate with cholesterol saturation index or nucleation time. In both group A and group B, cholesterol stone patients with cholesterol crystals in their fresh biles had a higher % deoxycholic acid, a lower % cholic acid and a higher bile salt hydrophobicity index than crystal-negative patients. This study indicates the need for further research on the role of bile salt hydrophobicity in the pathogenesis of gallstones.