A synthetic leu-enkephalin analogue prevents the natural activation of neutrophils induced by serum of patients with severe polytrauma

Abstract

Relevance. Multiple organ failure is the major cause of late mortality in patients with severe polytrauma. The pathogenesis of multiple organ failure primarily involves systemic inflammatory response syndrome (SIRS), oxidative stress, and ensuing endothelial dysfunction.

The aim of this study was to investigate the effect of a synthetic analogue of leu-enkephalin, Dalargin, at various doses on the pro-inflammatory activation and apoptosis of neutrophils induced in vitro by blood serum of patients with SIRS following severe polytrauma.

Materials and methods. The experiments were performed on neutrophils obtained from seven healthy donors. Neutrophils were activated by adding serum samples from severe polytrauma patients with SIRS. The neutrophil status was evaluated using immunofluorescence microscopy with antibodies against CD11b and CD66b. The prevalence of neutrophil apoptosis was assessed at 22 hours after the derivation; cell viability was determined after annexin V and propidium iodide staining by fluorescence-based flow cytometry. Intact and activated neutrophils were treated with Dalargin 1, 10, 50, and 100 µg/ml.

Results. Dalargin attenuated the degranulation and activation of neutrophils by suppressing the expression of CD11b and CD66b in the neutrophils pretreated with serum of patients with SIRS caused by severe polytrauma. This anti-inflammatory effect was dose-related. The Dalargin dose of >50 µg/ml was able to induce spontaneous apoptosis in neutrophils pre-treated with serum samples from patients with polytrauma-related SIRS.

Conclusion. Our findings provide potential opportunities for using Dalargin for prophylaxis and treatment of SIRS in patient with severe polytrauma as well as for prevention of multiple organ dysfunction.