A mechanism of protection was suggested by the enhanced expression of HIF-1a in the surviving epithelium. Expression of HIF-1a in response to low oxygen tension during ischemia and early reperfusion triggers Pectolinarigenin physiologic responses characterized by activation of functional proteins mucin, P-glycoprotein, intestinal trefoil factor and adenosine A2B receptor, aimed at preventing mucosal inflammation. The role in preserving gut wall integrity in response to IR as well as the exciting role of HIF-1a in different cardiac and brain pre-conditioning IR models underlines a possibly protective influence of increased HIF-1a mRNA expression as detected in our model in response to IR of the human intestine. Taken together, ischemia, sensed by the small intestine, induces normal physiological and IR induced responses. Our data provide new and compelling evidence of increased HIF-1a and also C3 gene expression during the reperfusion period. However, these responses are not paralleled by an IR induced inflammatory response, since important conditions to an inflammatory reaction have not been met by the absence of dead cells in the reperfused tissue. It is important to realize that these data indicate that the human intestine is more resistant to IR than initially thought. Its ability to shed damaged epithelial cells and repair its ever important barrier function without triggering massive inflammation can be seen as key features that prevent the gut from inflammation following splanchnic ischemia and reperfusion. In cardiac surgery, the use of cardioplegic cardiac arrest and cardiopulmonary bypass is known to trigger a significant release of reactive oxygen and nitrogen species. Termination of cardioplegic arrest by reperfusion leads to oxidative stress, which is a major contributor to the complex pathophysiology of ischaemia-reperfusion injury. Moreover, extracorporeal circulation by itself is known to stimulate the production of ROS in neutrophils and monocytes. When exceeding the endogenous antioxidant capacity, oxidative stress results in the oxidation of proteins, membrane 4′-Chloropropiophenone lipids and deoxyribonucleic acids.