Mouse Models of intestinal Bile Acid Malabsorption

摘要

Bile acids are synthesized from cholesterol in the liver and secreted into the small intestine, where they facilitate absorption of fat-soluble vitamins and cholesterol1. The majority of bile acids are reabsorbed from the intestine and returned to the liver via the portal venous circulation. At the sinusoidal membrane of the liver, bile acids are efficiently extracted and resecreted into bile2. This enterohepatic circulation of bile acids is an extremely efficient process; less than 10% of the intestinal bile acids escape reabsorption and are eliminated in the faeces3. Intestinal bile acids* are reclaimed through a combination of passive absorption in the jejunum and active transport in the distal ileum. The first step in the active transport of bile acids from the intestine is mediated by the well-characterized ileal apical sodium bile acid cotransporter (Asbt)4. This sodium-and potential-driven5 transporter moves bile acids from the lumen of the small intestine across the apical brush border membrane.