Analysis of the influence of antithrombin on microvascular thrombosis: anti-inflammation is crucial for anticoagulation

Abstract

Purpose: Microvascular thrombosis during septic conditions is of essential clinical relevance, but the pathomechanisms are not yet completely understood. The purpose of this study was to study the distinguished differentiation of the interactions of inflammation and coagulation using antithrombin (AT), a mediator of anticoagulation and anti-inflammation. Methods: Using a thrombosis model in a cremaster muscle preparation of male C57Bl/6J mice (n = 83), we quantitatively assessed microvascular thrombus formation by using intravital fluorescence microscopy. Experimental groups consisted of animals treated with AT or with tryptophan49-blocked AT (TrypAT), which exerts only anticoagulant but no anti-inflammatory effects. To further see whether endothelial glycosaminoglycan (GAG) binding with consecutive prostacyclin (PGI2) release is mandatory for the anticoagulant process of AT, animals were administered heparin or indomethacin either alone or in combination with AT. Results: The antithrombotic capacity of AT significantly differs in the experimental groups in which anti-inflammation was antagonized. This is given by the significantly prolonged occlusion times (p < 0.05) and higher patency rates in case of application of AT alone; while all other groups in which the anti-inflammatory action of AT was blocked by TrypAT, heparin or indomethacin revealed thrombus kinetics comparable to controls. Conclusions: The anti-inflammatory influence of AT is essentially linked to its anticoagulant effect in the microvascular system. Those specifications of the active profile of AT characterize the intimate interactions of the anticoagulant and anti-inflammatory pathways. This might be of relevance for AT as a therapeutic agent in critically diseased patients and the clinical understanding of microvascular thrombosis.