Guar gum consumption enhances hepatic ABCG5/G8 expression and increases ileal cholesterol excretion in pigs

Abstract

To investigate the potential molecular mechanisms by which guar gum (GG) consumption may modulate the enterohepatic metabolism of cholesterol, the mRNA and protein expression of genes that regulate the hepatobiliary secretion and intestinal absorption of cholesterol and/or bile acids were examined in pigs fed an atherogenic control diet or the control diet supplemented with 10% GG. Consumption of GG reduced apparent ileal cholesterol absorption by 59% (P=0.002) and increased ileal cholesterol excretion by 138% (P=0.01) compared with the control pigs. Consumption of GG increased the mRNA (1.2 fold of the control, P=0.04) and protein (1.7 fold of the control, P=0.05) expression of hepatic ATP‐binding cassette transporter (ABC) G5. Similarly, an increase in the mRNA (1.4 fold of the control, P=0.04) and protein (1.7 fold of the control, P=0.01) expression of hepatic ABCG8 was observed in the GG group. Biliary cholesterol concentration was increased by 29% (P = 0.07) in the GG‐fed pigs compared with the control group. The consumption of GG modulates hepatic cholesterol homeostasis by enhancing ABCG5/G8 expression and increases whole‐body cholesterol loss by reducing intestinal cholesterol absorption. Supported by OMAFRA of Canada.