INDUCING CHOLESTEROL PRECIPITATION FROM PIG BILE WITH BETA-CYCLODEXTRIN AND CHOLESTEROL DIETARY SUPPLEMENTATION

Background/Methods: In this study, pigs fed for 3 weeks a well-balance d semi-purified diet enriched with 0.3% cholesterol and 0, 5 or 10% be ta-cyclodextrin were proposed as new animal donors of gallbladder bile exhibiting different rates of cholesterol crystallization, in order t o gain insight into the early mechanisms underlying cholesterol precip itation in vivo, The appearance and growth of cholesterol crystals wer e monitored in the incubated freshly collected gallbladder biles throu gh light microscopy and concomitant time-sequential determination of c rystallized cholesterol concentration, and interpreted in terms of the composition of the bile. Results: Although the concentration of total lipids and proteins and the relative proportions of bile acids, phosp holipids, and cholesterol remained unchanged under beta-cyclodextrin, the cholesterol crystallization increased in the following order: 0<<1 0<5% beta-cyclodextrin, Concomitantly, the proportion of chenodeoxycho lic acid in bile, and the hydrophobicity index of the biliary bile aci d mixture increased in the following order: 0<5<10% beta-cyclodextrin (the same as reported elsewhere for the decrease in the antinucleating ApoA1), while sn-2 arachidonoyl biliary lecithins were specifically i ncreased with 5% beta-cyclodextrin in the diet. Conclusions: We hypoth esized that lecithin molecular species may be the determinant factor i n modulating high cholesterol crystallization rates in biles otherwise enriched with hydrophobic bile acids.