Expression of E-selectin and its transcripts during intestinal ischemia-reperfusion injury in pigs

Ischemia-reperfusion injury (IRI) can result in severe organ dys- or nonfunction. Interaction of leukocytes and endothelial cells mediated by E-selectin appears to be a key step for disturbed microcirculation. Therefore we studied gene and protein expression as well as localization of E-selectin during intestinal IRI.

Intestinal tissue samples were obtained from extracorporeal perfused intestines (cold ischemia time [CIT] 2 or 20 hours, each n = 5) and additionally in intestinal transplanted pigs (CIT 2 or 20 hours, each n = 1). Mucosal damage was graded according to the Chiu classification. E-selectin mRNA was determined by PCR and quantitative RT-PCR. Localization of E-selectin mRNA was performed by in situ hybridization and of the protein by immunohistochemistry.

Histologically, mucosal damage occurred during reperfusion and was earlier and more severe after 20 hours of CIT. E-selectin mRNA expression was detected by PCR already after laparotomy and was elevated after reperfusion. Interestingly, mRNA expression was already increased after 20 hours of CIT. E-selectin mRNA was localized to the luminal surface of muscular, submucosal, and mucosal endothelial cells and the protein was detected on submucosal arterial endothelium as early as 2 hours after reperfusion.

Prolongation of CIT results in more severe mucosal damage during reperfusion, which is associated with protein expression of E-selection that might be used as a marker for activated endothelial cells. Increased E-selectin mRNA at end of 20 hours of CIT might indicate a preactivated state of endothelial cells potentially triggered by bacterial translocation or products.