Studies of cholesterol and bile acid metabolism, and early atherogenesis in hamsters fed GT16-239, a novel bile acid sequestrant (BAS)

The purpose of this study was to compare the efficacy of GT16-239, an alkylated, cross-linked poly(allylamine) bile acid sequestrant with cholestyramine on cholesterol and bile acid metabolism, and early aortic atherosclerosis in hypercholesterolemic male FIB Golden Syrian hamsters. In this controlled study, 42 hamsters were divided into six groups and were fed a chow-based hypercholesterolemic diet supplemented with a 100% oil blend (55% coconut/45% corn), 0.1% cholesterol (w/w) (control) and either 0.9 or 1.2% cholestyramine or 0.2, 0.4 or 0.6% GT16-239 for 13 weeks. Laboratory analyses included evaluating plasma lipoprotein cholesterol and triglyceride concentrations, hepatic HMG-CoA reductase and 7 alpha-hydroxylase activities, fecal excretion of bile acids and neutral sterols, hepatic cholesterol concentrations, and early atherosclerosis (aortic fatty streak area). Relative to the control diet, the 0.6% GT16-239 versus the 1.2% cholestyramine significantly inhibited the elevation of plasma lipoprotein total cholesterol (TC) (- 69% vs - 40%), high density lipoprotein-cholesterol (HDL-C) (-49% vs - 30%), and non-HDL-C (- 81% vs -48%) concentrations; increased the activities of both HMG-CoA reductase (1492% vs 62%) and 7 a-hydroxylase (175% vs 86%); lowered the concentration of hepatic cholesteryl ester (-94% vs -59%); increased fecal cholesterol concentration (+ 28% vs - 10%); and decreased aortic fatty streak area (- 100% vs - 86%). Unexpected findings of this comparison were increased fecal concentrations of cholic acid (533%) and chenodeoxycholic acid (400%) and the reduction in lithocholic acid (- 50%) in the 0.6% GT16-239 compared to the 1.2% cholestyramine group. In summary, GT16-239 had a greater impact on cholesterol metabolism and early atherosclerosis in hypercholesterolemic hamsters than cholestyramine. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.