Localization and changes of diamine oxidase during cardiopulmonary bypass in rabbits

BACKGROUND: We previously observed increased serum diamine oxidase activity during clinical cardiopulmonary bypass, indicating small intestinal mucosal ischemia followed by bacterial translocation. MATERIALS AND METHODS: In seven female rabbits undergoing cardiopulmonary bypass for 1 h, we analyzed the localization of diamine oxidase immunohistochemically, and measured its activity in serum and abdominal organs before and after cardiopulmonary bypass (CPB). RESULTS: Preoperatively, diamine oxidase activity and immunoreactivity were high in the small intestine, localized to villus tips. Serum activity increased significantly after CPB, whereas small intestinal diamine oxidase decreased with mucosal injury. CONCLUSIONS: In this model serum diamine oxidase activity appeared to reflect CPB induced intestinal mucosal injury.