A recombinant fragment of von Willebrand factor reduces fibrin-rich microthrombi formation in mice with endotoxemia

Abstract

Introduction Disseminated fibrin deposition in the microvasculature such as in disseminated intravascular coagulation (DIC) arises from uninhibited activated coagulation secondary to sustained systemic inflammation. Currently there is no treatment for DIC. Treating the underlying trigger and supportive care are the current recommendations to manage DIC. This study aims at using recombinant von Willebrand factor (VWF) A2 domain polypeptide to inhibit VWF–mediated platelet adhesion to fibrin and prevent DIC. Materials and Methods We use flow chamber assay to test the capacity of purified A2 protein to inhibit platelet adhesion to immobilized fibrin(ogen) and platelet-fibrin clot formation. We use a murine model of lipopolysaccharide-induced DIC to examine the effect of A2 protein on DIC. Results The A2 protein blocked flow-dependent platelet adhesion to fibrin, delayed fibrin polymerization, and inhibited platelet-fibrin clot formation in vitro. The infusion of the purified A2 protein to the endotoxin-treated mice prevented fibrin-rich microthrombi formation in brain, lung, kidney, and liver. It also attenuated levels of inflammatory mediators, and markedly reduced mortality rates at 96 hours. Conclusions The A2 protein inhibited platelet interaction with fibrin(ogen). Furthermore, A2 prevented disseminated fibrin-rich microthrombi and decrease mortality in a lipopolysaccharide-induced DIC murine model. A2 could provide a novel therapeutic approach in critically ill patients with uninhibited activated coagulation and disseminated fibrin deposition such as DIC.

Thrombocytopenia-Associated Multiple Organ Failure and Acute Kidney Injury

“…99 The authors have recently reported using a recombinant VWF A2 polypeptide that inhibits platelet-fibrin (estropipate [Ogen]) interaction to reduce disseminated microvascular thromboses and mortality in an endotoxemia-induced DIC murine model. 100 …”

Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation

“…Importantly, the A2 protein decreased mortality from 60% to 0% and attenuated disseminated microvascular thrombosis in an endotoxemia-induced DIC murine model. 13 However, it was unclear whether A2 protein-fibrin binding was the main mechanism by which the A2 protein led to improved survival in our lipopolysaccharide (LPS)-induced DIC murine model. Therefore, the goal of our current study was to elucidate further the molecular mechanism by which the A2 protein improves survival and attenuates DIC in endotoxemic mice.…”

“…The recombinant A1 domain protein was produced as described previously. 13,16 Imaging the fibrin clot structure…”

“…Fibrin formation was evaluated by turbidity assay using healthy human plasma or endotoxemic plasma as described. 13 The progression of fibrin clot formation was evaluated by tracking turbidity using a spectrophotometer set to l 405 nm. Fibrinolysis was performed by mixing human healthy plasma with the A2 protein (2.0 or 4.0 mM) or saline in the presence of 150 ng/mL of tissue plasminogen activator (Cathflo Activase) and 0.1 U of human thrombin.…”

Endothelial Cell von Willebrand Factor Secretion in Health and Cardiovascular Disease

“…In conclusion, excessive levels of the highly prothrombotic and multimeric form of vWF and/or ADAMTS13 deficiency constitute a unifying pathologic mechanism linking inflammation to thrombosis [170].…”