BILIARY LIPID-COMPOSITION IN HETEROZYGOUS FAMILIAL HYPERCHOLESTEROLEMIA AND INFLUENCE OF TREATMENT WITH PROBUCOL

The lipid composition of fasting duodenal bile was determined in 11 he althy subjects with normolipidemia and 15 patients with heterozygous f amilial hypercholesterolemia (FH) (12 with type IIa, three with type I Ib). The age distribution among the groups of subjects was similar, In the patients with heterozygous FH type IIa, the mean value for molar percentage of cholesterol and lithogenic index (LI) of bile were signi ficantly higher than those of controls (8.4 +/- 1.0%, 1.47 +/- 0.18 ca lculated by Hegard, Dam, and Holzbach vs 4.3 +/- 0.4%, 0.81 +/- 0.07, respectively). The value of LI in the patients with FH type Ifo was al so found to be significantly higher than that of the controls. In the patients with heterozygous FH type IIa, we observed both a significant decrease in the molar percentages of glycochenodeoxycholic acid, glyc oursodeoxycholic acid, and glycolithocholic acid, and a significant in crease of taurochenodeoxycholic acid compared to the corresponding val ues in the controls. Bile analysis of six patients was reexamined duri ng probucol treatment after 16 weeks. Probucol significantly lowered s erum cholesterol levels. However, biliary lipid composition and indivi dual bile acid proportions was not altered by the treatment. The resul ts suggest that most of the patients with heterozygous FH have supersa turated bile and are predisposed to cholesterol gallstone formation. I n addition, the mechanism by which probucol lowers serum cholesterol a ppears to be independent of any change in the metabolism of biliary li pid.