DISTINCT IMMUNO-LOCALIZATION OF MUCIN AND OTHER BILIARY PROTEINS IN HUMAN CHOLESTEROL GALLSTONES

Background/Aims: Cholesterol gallstones consist of cholesterol crystal s and smaller amounts of pigments and calcium salts, arrayed on a muci n plus protein matrix, The localization of the various biliary protein s in the stones has not been characterized. We aimed to localize sever al biliary proteins in gallstones in order to determine their possible role in stone formation and growth. Methods: The distribution of seve ral matrix proteins and their relationships to the minerals were deter mined using immunostaining and EDAX microanalysis on hemisected choles terol gallstones. Results: Pigment areas were rich in calcium and cont ained Cu, P and S. These elements were absent in cholesterol regions. Mucin was identified in a three-dimensional network intercalated betwe en cholesterol crystals and as septa between deposits of pigments and cholesterol; APF/CBP and ApN coated only the pigment deposits, No spec ific topographical localization was found for albumin or IgA. Conclusi ons: This suggests a role for mucin, APF/CBP and ApN in the formation of cholesterol gallstones, We propose that cholesterol crystals bind d irectly to mucin, whereas calcium salts and pigments deposit on APF/CB P and ApN bind to the mucin.