Figure 4.

A schematic representation of adhesion molecules within liver sinusoids. LSECs express a number of adhesion molecules, including VCAM-1, MadCAM-1, and ICAM-1 that bind to the integrins α4β1, α4β7, and the β2 family. VCAM-1 is expressed at levels within sinusoids that other tissues only express under inflammatory conditions. ICAM-1 is also expressed by LSECs at levels that are normally seen in post-capillary venules. MadCAM-1 is normally only expressed in the gut, directing immune cells to the intestine; however, this becomes an important mediator in PSC when aberrantly expressed by LSECs. ICAM-1 is expressed on the basal membrane, whereas VCAM-1 and MadCAM-1 are expressed on the luminal membrane.