Inhibition of Vascular Endothelial Cell Leak Following Escherichia coli Attachment in an Experimental Model of Sepsis

Objectives: The vascular endothelium is a major target of sepsis-induced events, and endothelial activation accounts for much of the pathology of sepsis. Urinary tract infections and pneumonia caused by Escherichia coli are among of the most common infections causing sepsis in both community and hospital settings. Currently, there are no approved drugs on the market to treat the underlying pathophysiology of sepsis. The aim of this study is to elucidate the molecular mechanism by which E. coli induces endothelial injury as a result of attachment. Design: Laboratory research using a hemodynamic perfusion ex vivo model. Setting: Research Laboratories of Royal College of Surgeons in Ireland and Beaumont Hospital. Patients: Ex vivo human vascular endothelial cells. Interventions: Addition of αVβ3 antagonist, cilengitide. Measurements and Main Results: Clinical strains of E. coli isolated from patients with sepsis bound to sheared human endothelial cells under static and hemodynamic shear conditions. Binding was dependent on E. coli cell membrane protein outer membrane protein A attaching directly to endothelial cell integrin αVβ3. Attachment resulted in disturbances in endothelial barrier integrity, as determined by loss of tight junction protein staining, permeability changes, and ultimately cell death by apoptosis. Using a low concentration of the αVβ3 antagonist cilengitide or using a strain deficient in outer membrane protein A resulted in a significant reduction in endothelial dysfunction following infection. Conclusions: Inhibition of E. coli binding to endothelial cell αVβ3 by cilengitide prevents endothelial dysfunction and may, therefore, present as a novel early therapeutic for the treatment of sepsis.