Biliary lipids in familial combined hyperlipidaemia: effects of acipimox therapy

Biliary lipid composition and plasma lipoprotein levels were determined in nine gallstone-free male patients with familial combined hyperlipidaemia (FCHL). In the basal situation, stimulated fasting duodenal bile from the patients contained a higher relative concentration of cholesterol than bile obtained from age- and sex-matched normal controls (n = 22), 6.5 +/- 0.3 (SEM) vs. 4.7 +/- 0.2 mol % (P less than 0.01). This resulted in a higher cholesterol saturation of bile from FCHL patients, 85 +/- 6 vs. 70 +/- 2% (P less than 0.05). After 6 weeks of treatment with acipimox, 750 mg day-1, total plasma triglycerides were lowered from 7.5 +/- 1.5 to 4.6 +/- 0.7 mmol l-1 (P less than 0.05) and plasma cholesterol decreased from 8.0 +/- 0.1 to 7.1 +/- 0.3 mmol l-1 (P less than 0.05) in the FCHL patients. These changes were mainly due to a decrease in very low density lipoprotein concentrations while low density lipoprotein levels remained unaltered. The relative proportion of cholesterol in stimulated fasting duodenal bile was reduced from 6.5 +/- 0.3 to 4.3 +/- 0.5 mol % (P less than 0.01), resulting in 'normalization' of biliary cholesterol saturation, from 85 +/- 6 to 58 +/- 6% (P less than 0.005). No correlations between the changes in biliary lipid composition and those in plasma lipoprotein levels were observed. The results indicate that treatment with acipimox in patients with FCHL, a disorder commonly associated with supersaturated bile, does not increase biliary cholesterol, and presumably not the risk for gallstone formation.