Grape Seed Procyanidins and Cholestyramine Differentially Alter Bile Acid and Cholesterol Homeostatic Gene Expression in Mouse Intestine and Liver.
Bile acid (BA) sequestrants, lipid-lowering agents, may be prescribed as a monotherapy or combination therapy to reduce the risk of coronary artery disease. Over 33% of adults in the United States use complementary and alternative medicine strategies, and we recently reported that grape seed procyanidin extract (GSPE) reduces enterohepatic BA recirculation as a means to reduce serum triglyceride (TG) levels. The current study was therefore designed to assess the effects on BA, cholesterol and TG homeostatic gene expression following co-administration with GSPE and the BA sequestrant, cholestyramine (CHY). Eight-week old male C57BL/6 mice were treated for 4 weeks with either a control or 2% CHY-supplemented diet, after which, they were administered vehicle or GSPE for 14 hours. Liver and intestines were harvested and gene expression was analyzed. BA, cholesterol, non-esterified fatty acid and TG levels were also analyzed in serum and feces. Results reveal that GSPE treatment alone, and co-administration with CHY, regulates BA, cholesterol and TG metabolism differently than CHY administration alone. Notably, GSPE decreased intestinal apical sodium-dependent bile acid transporter (Asbt) gene expression, while CHY significantly induced expression. Administration with GSPE or CHY robustly induced hepatic BA biosynthetic gene expression, especially cholesterol 7α-hydroxylase (Cyp7a1), compared to control, while co-administration further enhanced expression. Treatment with CHY induced both intestinal and hepatic cholesterologenic gene expression, while co-administration with GSPE attenuated the CHY-induced increase in the liver but not intestine. CHY also induced hepatic lipogenic gene expression, which was attenuated by co-administration with GSPE. Consequently, a 25% decrease in serum TG levels was observed in the CHY+GSPE group, compared to the CHY group. Collectively, this study presents novel evidence demonstrating that GSPE provides additive and complementary efficacy as a lipid-lowering combination therapy in conjunction with CHY by attenuating hepatic cholesterol synthesis, enhancing BA biosynthesis and decreasing lipogenesis, which warrants further investigation.
Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America.
Rebecca M
RM
Heidker
Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America.
Gianella C
GC
Caiozzi
Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America.
Marie-Louise
ML
Ricketts
D000818:Animals; D044946:Biflavonoids / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism*; D001835:Body Weight; D002392:Catechin / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D002792:Cholestyramine Resin / Q000378:metabolism*; D005243:Feces; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D056604:Grape Seed Extract / Q000494:pharmacology*; D006706:Homeostasis; D007413:Intestinal Mucosa / Q000378:metabolism*; D008055:Lipids / Q000737:chemistry; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D044945:Proanthocyanidins / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism
D044946:Biflavonoids; D001647:Bile Acids and Salts; D056604:Grape Seed Extract; D008055:Lipids; D044945:Proanthocyanidins; D014280:Triglycerides; D002792:Cholestyramine Resin; C017674:procyanidin; D002392:Catechin; D002784:Cholesterol