Interactions between neutrophil extracellular traps and activated platelets enhance procoagulant activity in acute stroke patients with ICA occlusion

Abstract

Background: The role of neutrophil extracellular traps (NETs) in procoagulant activity (PCA) in stroke patients caused by thromboembolic occlusion of the internal carotid artery (ICA) remains unclear. Our objectives were to evaluate the critical role of NETs in the induction of hypercoagulability in stroke and to identify the functional significance of NETs during atherothrombosis. Methods: The levels of NETs, activated platelets (PLTs), and PLT-derived microparticles (PMPs) were detected in the plasma of 55 stroke patients and 35 healthy controls. NET formation and thrombi were analysed using immunofluorescence. Exposed phosphatidylserine (PS) was evaluated with flow cytometry and confocal microscopy. PCA was analysed using purified coagulation complex, thrombin, and fibrin formation assays. Findings: The plasma levels of NETs, activated PLTs, and PMP markers in the carotid lesion site (CLS) were significantly higher than those in the aortic blood. NETs were decorated with PS in thrombi and the CLS plasma of ICA occlusion patients. Notably, the complementary roles of CLS plasma and thrombin-activated PLTs were required for NET formation and subsequent PS exposure. PS-bearing NETs provided functional platforms for PMPs and coagulation factor deposition and thus increased thrombin and fibrin formation. DNase I and lactadherin markedly inhibited these effects. In addition, NETs were cytotoxic to endothelial cells, converting these cells to a procoagulant phenotype. Sivelestat, anti-MMP9 antibody, and activated protein C (APC) blocked this cytotoxicity by 25%, 39%, or 52%, respectively. Interpretation: NETs played a pivotal role in the hypercoagulability of stroke patients. Strategies that prevent NET formation may offer a potential therapeutic strategy for thromboembolism interventions.

Platelets and Metastasis: New Implications of an Old Interplay

“…Additionally, tumor cells disseminating to the lung and liver recruit and activate neutrophils to release of extracellular DNA traps (NETs) intravascularly ( 131 , 132 ). NETs induce platelet aggregation through PS exposure, PMP accumulation and endothelial cell activation, and are associated with increased hypercoagulability and risk of venous thromboembolism in cancer patients ( 133 – 135 ). Interestingly, platelets interacting with tumor cells through the TLR4 axis can also activate NETs formation through a P-selectin-dependent mechanism ( 136 , 137 ), further amplifying thrombosis.…”

COVID‑19 and ischemic stroke: Mechanisms of hypercoagulability (Review)

“…Thus, it is reasonable to believe that activated platelets promote hypercoagulability. On the one hand, activated platelets release microparticles (MPs), VWF and PAI to promote coagulation ( 27 ), and promote the generation of NETs that participate in the formation of hypercoagulability ( 33 ). Moreover, platelet activation is a prominent feature of AIS.…”

“…Their study also found that plasma cf-DNA levels were positively associated with plasma D-dimer levels, suggesting that NETs were associated with hypercoagulability in patients ( 37 ). Previous research has demonstrated the presence of NETs in thrombi and the peripheral blood of patients with AIS, and the NET content in peripheral blood is associated with the hypercoagulability of patients with AIS ( 33 ). Based on the above-mentioned studies, it can be hypothesized that NETs in patients with COVID-19 lead to a hypercoagulable state that induces AIS ( Fig.…”

Insights Into Immunothrombosis: The Interplay Among Neutrophil Extracellular Trap, von Willebrand Factor, and ADAMTS13

“…These results implied that the amount of NETs is associated with the density of platelets in stroke thrombi. Moreover, a recent study reported that interactions between NETs and activated platelets played an important role in the hypercoagulability of stroke patients with ICA occlusion ( 158 ). Plasma from carotid lesion site in stroke patients not only induced platelet activation in a thrombin-dependent manner, but also exposed phosphatidylserine (PS, a critical catalyst in the coagulation cascade) on the surfaces of platelets, platelet-derived microparticles (PMPs) and neutrophils.…”

“…Activated platelets mediated the formation of NETs decorated with PS. These PS-bearing NETs were observed in the carotid thrombus and provided a platform to bind PMPs and coagulation factors, including prothrombin, fibrinogen, and Factor X, and thus promoted thrombin and fibrin formation ( 158 ).…”