Thrombin stories in the gut

Many studies have demonstrated the involvement of proteases in gut physiology and pathophysiology over the recent years. Among them, thrombin has appeared for a long time as an old player only involved in blood clotting upon tissue injury. The fact that thrombin receptors (Protease-Activated Receptors-1 and -4) are expressed and functional in almost all cell types of the gut, contributing to barrier, immune or motility functions, suggested that thrombin could actually be at the crossroad of intestinal physiology. Recent work has unraveled the constitutive release of active thrombin by intestinal epithelial cells, opening new research avenues on the role of thrombin in the gut. These roles are considered in the present review, as well as the regulation of thrombin in the gut. The potential of thrombin as a target for treatments of intestinal pathologies is also discussed here.