Ileal sodium-dependent bile acid transporter (ASBT) (ASBT)

The Ileal sodium-dependent bile acid transporter (ASBT), encoded by the SLC10A2 gene, is a transmembrane protein primarily expressed on the apical membrane of enterocytes in the distal ileum (UniProt Consortium, 2024). Its primary biological function is to mediate the active reabsorption of bile acids from the intestinal lumen into the portal circulation, a critical step in the enterohepatic circulation that conserves approximately 95% of the bile acid pool (Dawson et al., 2009). By regulating the return of bile acids to the liver, ASBT plays a significant role in maintaining cholesterol homeostasis and modulating signaling through bile acid-activated receptors (Karpen & Dawson, 2015). In cholestatic liver diseases such as Alagille syndrome and progressive familial intrahepatic cholestasis (PFIC), impaired bile flow leads to toxic systemic accumulation of bile acids, which causes severe pruritus and progressive liver damage (Heubi et al., 2007). Pharmacological inhibition of ASBT by drugs like maralixibat and odevixibat prevents this reabsorption, promoting the excretion of bile acids in feces and effectively reducing the systemic bile acid burden (FDA, 2021). This therapeutic mechanism is also utilized to treat chronic idiopathic constipation by increasing the osmotic load in the colon and is being investigated for metabolic conditions like NASH (Karpen & Dawson, 2015).

Other names

Apical sodium-dependent bile acid transporterIleal bile acid transporterIBATSLC10A2Sodium/bile acid cotransporter

Inhibition of apical sodium-dependent bile acid transport in the ileum to reduce systemic bile acid levels and increase fecal excretion.