Hypolipidemic effects of β‐cyclodextrin in the hamster and in the genetically hypercholesterolemic rico rat

Abstract
The effect of increasing amounts of a cyclic oligosaccharide, β‐cyclodextrin (BCD), included in the diet on plasma cholesterol and triglycerides, was investigated in two animal models, namely in male genetically hypercholesterolemic Rico rats and in male Syrian hamsters. The distribution of bile acids in the gastrointestinal tract and in the feces of hamsters was also determined. In the Rico rats and hamsters, plasma cholesterol and triglycerides decreased linearly with increasing doses of BCD. In these two species, 20% BCD as compared to control diet lowered cholesterolemia (−35%) and triglyceridemia (−70%). In the hamster, the BCD diet caused a marked decrease in cholesterol and triglycerides in chylomicrons and very low density lipoprotein, and in high density lipoproteins cholesterol. Composition and amounts of bile acids were modified in the gastrointestinal tract of hamsters receiving 10% BCD as compared to the control group. The total bile acid content of the gallbladder of treated hamsters was fourfold higher than in the control group, and the bile contained a large amount of hydrophilic bile acids. This trend was also observed in the small intestine, in which percentages and total quantities of cholic plus deoxycholic acids (cholic pathway) were higher than those of chenodeoxycholic plus ursodeoxycholic plus lithocholic acids (chenodeoxycholic pathway). The bile acid contents of the cecum and colon of treated hamsters were 2.7‐fold higher than those of control animals, but the bile acid composition was similar in the two groups of hamsters. Fecal excretion of bile acids was 3.3‐fold higher in the treated group than in the control group, and the percentage of lithocholic acid was markedly increased and close to that observed in the colon. The turnover of the chenodeoxycholic pool was twice as fast in treated hamsters as in control hamsters, whereas that of cholic acid was not significantly modified. These results suggest that BCD does not alter the microbial degradation of bile acids, but rather stimulates their synthesis and increases their pool size. BCD prevents the intestinal absorption of lithocholic acid and washes this cytotoxic bile acid from the colon. The hypocholesterolemic effect of BCD appears to be due to stimulation of bile acid synthesis.

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