Interrelationships of bile acid and phospholipid fatty acid species with cholesterol saturation of duodenal bile in health and gallstone disease

Authors

  • Dr. Frieder Berr,

    Corresponding author
    1. Department of Medicine II, University of Munich, 8000 Munich 70, Germany
    • Medizinische Klinik II, Klinikum Grosshadern, Marchioninistr.15, 8000 München 70, Germany
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  • Dr. Edgar Schreiber,

    1. Department of Medicine II, University of Munich, 8000 Munich 70, Germany
    Current affiliation:
    1. Institut f. Botanik, Universitaet Marburg, Am Lahnberge 3, 3550 Marburg, Germany
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  • Ulrich Frick

    1. Biometric Centre, University of Munich, 8000 Munich 70, Germany
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Abstract

The relative amount of cholesterol and the fatty acid composition of phosphatidylcholines in bile can be influenced by the bile acid species secreted. To search for a contribution of secondary bile acids and of phosphatidylcholines to supersaturation of bile in gallstone disease, we compared the relative amount of cholesterol and the biliary composition of bile acids and of phospholipid fatty acids in cholecystokininstimulated duodenal bile of 22 female gallstone patients and 16 healthy controls and analyzed the interrelationships of these bile constituents. Gallstone patients had higher molar percentages of cholesterol than did controls (10.2 ± 3.2 vs. 6 ± 1.5 mol%; p < 0.001) and demonstrated a trend toward larger fractions of deoxycholic and lithocholic acids. By linear models, variation of cholesterol saturation could be predicted (p < 0.001) up to 53% by the bile acid pattern and up to 81% by the fatty acid pattern of phospholipids. Linear path analysis (goodness-of-fit index = 0.973) confirmed the tight relationship between phospholipid fatty acids (positive: oleic, arachidonic; negative: Iinoleic, palmitoleic) and the relative amount of cholesterol; more than half the influence of cholic, deoxycholic and lithocholic acids on the relative amount of cholesterol could be explained indirectly by their influence on the phospholipid fatty acid pattern. We conclude that the relationships examined by path analysis support the working hypothesis that secondary bile acids contribute to supersaturation of bile mainly by changing the fatty acid pattern of the secreted phospholipids (presumably the pattern of phosphatidylcholines), which increases the molar ratio of cholesterol/phospholipids in bile. (HEPATOLOGY 1992;16:71–81.)

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