Discrepant Fibrinolytic Response in Plasma and Whole Blood during Experimental Endotoxemia in Healthy Volunteers

Sisse R Ostrowski,Pär I Johansson,Nis A Windeløv,Ronni R Plovsing,Kirsten Møller,Martin A S Meyer,Ronan M G Berg,Samir M Parikh

doi:10.1371/journal.pone.0059368

Abstract

BackgroundSepsis induces early activation of coagulation and fibrinolysis followed by late fibrinolytic shutdown and progressive endothelial damage. The aim of the present study was to investigate and compare the functional hemostatic response in whole blood and plasma during experimental human endotoxemia by the platelet function analyzer, Multiplate and by standard and modified thrombelastography (TEG).MethodsProspective physiologic study of nine healthy male volunteers undergoing endotoxemia by means of a 4-hour infusion of E. coli lipopolysaccharide (LPS, 0.5 ng/kg/hour), with blood sampled at baseline and at 4 h and 6 h. Physiological and standard biochemical data and coagulation tests, TEG (whole blood: TEG, heparinase-TEG, Functional Fibrinogen; plasma: TEG±tissue-type plasminogen activator (tPA)) and Multiplate (TRAPtest, ADPtest, ASPItest, COLtest) were recorded. Mixed models with Tukey post hoc tests and correlations were applied.ResultsEndotoxemia induced acute SIRS with increased HR, temperature, WBC, CRP and procalcitonin and decreased blood pressure. It also induced a hemostatic response with platelet consumption and reduced APTT while INR increased (all p<0.05). Platelet aggregation decreased (all tests, p<0.05), whereas TEG whole blood clot firmness increased (G, p = 0.05). Furthermore, during endotoxemia (4 h), whole blood fibrinolysis increased (clot lysis time (CLT), p<0.001) and Functional Fibrinogen clot strength decreased (p = 0.049). After endotoxemia (6 h), whole blood fibrinolysis was reduced (CLT, p<0.05). In contrast to findings in whole blood, the plasma fibrin clot became progressively more resistant towards tPA-induced fibrinolysis at both 4 h and 6 h (p<0.001).ConclusionsEndotoxemia induced a hemostatic response with reduced primary but enhanced secondary hemostasis, enhanced early fibrinolysis and fibrinogen consumption followed by downregulation of fibrinolysis, with a discrepant fibrinolytic response in plasma and whole blood. The finding that blood cells are critically involved in the vasculo-fibrinolytic response to acute inflammation is important given that disturbances in the vascular system contribute significantly to morbidity and mortality in critically ill patients.

Highlights

Experimental human endotoxemia induced by intravenous administration of purified standard reference lipopolysaccharide (LPS) to healthy volunteers induces an acute systemic inflammatory response, which mimics the inflammatory response of early sepsis as well as other acute inflammatory conditions [1,2,3]
We report that experimental endotoxemia by means of a 4hour 0.5 ng/kg/hour LPS-infusion in healthy volunteers induced a hemostatic response with reduced primary but enhanced secondary hemostasis, enhanced early fibrinolysis and fibrinogen consumption followed by downregulation of fibrinolysis, with a discrepant fibrinolytic response in plasma and whole blood
With regard to routine coagulation tests, platelet count, activated partial thromboplastin time (APTT) and factor II, VII and X decreased and international normalized ratio (INR) increased whereas plasma fibrinogen, D-dimer and antithrombin did not change (Table 1)

Summary

Introduction

Experimental human endotoxemia induced by intravenous administration of purified standard reference lipopolysaccharide (LPS) to healthy volunteers induces an acute systemic inflammatory response, which mimics the inflammatory response of early sepsis as well as other acute inflammatory conditions [1,2,3]. Sepsis is associated with initial activation of coagulation and fibrinolysis followed by late fibrinolytic shutdown and exhaustion of the natural anticoagulant systems [4], the latter mainly due to progressive endothelial disruption and damage [5,6]. Conventional coagulation tests like activated partial thromboplastin time (APTT), international normalized ratio (INR), platelet count, plasma fibrinogen and D-dimer neither reveal (changes in) fibrinolysis nor platelet (dys)function, both of which may contribute significantly to hyper- and hypocoagulability in critically ill patients. Sepsis induces early activation of coagulation and fibrinolysis followed by late fibrinolytic shutdown and progressive endothelial damage. The aim of the present study was to investigate and compare the functional hemostatic response in whole blood and plasma during experimental human endotoxemia by the platelet function analyzer, Multiplate and by standard and modified thrombelastography (TEG)

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Conclusion