J. T. McGinn1, W. Yang1,2, F. Zhang2, M. Aziz2, J. M. Nicastro1, G. Coppa1, P. Wang1,2 1Northwell Health,Surgery,MANHASSET, NEW YORK, USA 2The Feinstein Institute For Medical Research,Center For Immunology And Inflammation,MANHASSET, NEW YORK, USA
Introduction: Gut ischemia-reperfusion (I/R) can occur in shock and mesenteric occlusive diseases. I/R injury is the result of a maladaptive inflammatory response in addition to the ischemic insult. Gut I/R can cause local tissue damage, as well as remote organ damage, particularly lung injury. Extracellular cold-inducible RNA-binding protein (CIRP) functions as a damage-associated molecular pattern (DAMP) and has been demonstrated to be responsible for the damage occurring after I/R. A short peptide derived from CIRP, named C23, has demonstrated efficacy in blocking extracellular CIRP action by binding to CIRP’s binding site on Toll-like receptor 4 (TLR4)-myeloid differentiation factor 2 (MD2) complex. We hypothesize that C23 acts as a CIRP antagonist and reduces inflammation and tissue injury induced by gut I/R.
Methods: Male C57BL/6 mice (20-30 g) were subjected to 60-min of intestinal ischemia by clamping the superior mesenteric artery, after which the clamps were removed to allow reperfusion. Immediately after reperfusion, either normal saline (vehicle) or C23 peptide treatment (8 mg/kg body weight) was injected intraperitoneally into the animals. Four hours after reperfusion, blood, lungs and gut were collected for various analyses (Table 1). Animals without surgery served as the control group.
Results:After I/R, the serum levels of the organ injury markers LDH and AST were increased in the vehicle-treated animals, while C23 treated animals exhibited a significant reduction in LDH and AST by 48% and 53%, respectively. The serum levels of the proinflammatory cytokine TNF-a were elevated by 25-fold in the vehicle-treated mice, while this was decreased by 72% in C23-treated group. Similarly, TNF-a protein levels in the gut and IL-6 mRNA levels in the lungs were reduced by 69% and 86%, respectively, in the C23-treated group in comparison to the vehicle-treated group. Moreover, the expression of MIP-2 and the level of MPO in the lungs were dramatically increased after I/R and reduced by 91% and 25%, respectively, in the C23-treated group. Additionally, the expression of COX2 in the lungs after I/R was also decreased by 57% with C23 treatment as compared to vehicle group.
Conclusion:Treatment with the short peptide C23, an antagonist for extracellular CIRP activity, not only decreases inflammation at the local level in the gut but also systemically and remotely in the lungs after gut I/R. C23 treatment also shows a reduction of organ injury induced by I/R. Therefore, C23 peptide could be an effective therapeutic candidate in gut I/R injury.
