Reperfusion injury.

In conclusion, a large body of evidence demonstrates that reperfusion of ischemic intestine results in significant microvascular and parenchymal cell injury. Reperfusion injury appears to be mediated by both reactive oxygen metabolites and activated polymorphonuclear leukocytes. Xanthine oxidase-derived oxidants initiate the production and release of proinflammatory agents, which in turn lead to polymorphonuclear leukocyte adherence and emigration. The adherent leukocytes mediate microvascular injury by either release of proteases, physical disruption of the endothelial barrier, or both.