A. Eitel1, M. Kelher3, E. Moore1,2, M. Cohen1,2, N. Vigneshwar1, J. Hadley1, M. Bartley1, M. Debot1, D. Kissau1, C. Silliman1,3 1University Of Colorado Denver,Surgery,Aurora, CO, USA 2Denver Health Medical Center,Surgery,Aurora, CO, USA 3Vitalant Research Institute,Denver, CO, USA
Introduction:
Polymorphonuclear neutrophils (PMNs) are an integral part of innate immunity through eradication of pathogens and are key mediators in ARDS and multiple organ failure post-injury. Priming of PMNs causes adherence to the vascular endothelium and hyper-reactivity, such that agents that usually do not activate the respiratory burst cause PMN activation and release of reactive oxygen species (ROS), endothelial damage, and organ injury. Severe injury causes the release of many potential mediators which may act as a first event including circulating bradykinin (BK); and a second insult, such as bacterial infection, reperfusion injury, etc., will activate these primed PMNs, releasing ROS. We hypothesize that BK primes PMNs and a BK antagonist (HOE140) will inhibit priming.
Methods:
PMNs were isolated from whole blood from healthy volunteers. PMNs were incubated with 31.2-1000 ng/ml of BK for 5 min at 37 º C, and activated with 1 μM fMLF. Priming, augmentation of the fMLF-activated respiratory burst, was measured by the maximal rate of O2– production by cytochrome C reduction. Pre-incubation with HOE140, a bradykinin receptor antagonist, followed by BK stimulation, assessed for inhibition. Statistical differences were determined via an ANOVA (p<0.05).
Results:
Compared to vehicle controls BK primed PMNs at all tested concentrations (p=0.013), which was inhibited by HOE140 (81.4±33.3%) at the highest concentrations.
Conclusion:
Severe injury causes the release of mediators, such as BK, priming PMNs and predisposing the patient to ARDS and MOF post-injury. BK, a component of the coagulation cascade, induces activation of innate immunity providing evidence for crosstalk between it and the coagulation system. This data also suggests HOE140 may be useful in inhibiting kininopathy caused by BK.
