ETD

• Bile acids
• cholesterol
• Enterohepatic circulation
• Fibres
• FXR
• Intestine
• Liver

Bile acids are not only simple molecules that permit digestion of fat and vitamins, but they are involved in the enterohepatic circulation to modulate their own synthesis and cholesterol turn over. Farnesoid X receptors in the ileum bound bile acids and let fibroblast growth factor 15 (Fgf15) reach the liver to down regulated cyp7A1, the rate limiting enzyme in the bile acids production from the cholesterol. We want to investigate if the different expression of Fgf15 by two diets is FXR dependent: chow diet with high fibres content and a low fibres diet. Three molecules have been used to modulate FXR expression: guggulsterone, a FXR antagonist; fexaramine, a FXR agonist; cholestyramine, a bile acids chelator. We analysed gene involved by qPCR, caspase 3 activity, hystology of ileum and liver, bile acids, triglycerides and cholesterol measurement.
High fibres intake is associated with a reduction in bile acid pool, associated with a decreased of lipid storage in hepatic tissue. Differential Fgf15 expression by soluble fibres seems to be independent from FXR.