Dong, Jing-fei

ABSTRACT Background: Neutrophil extracellular traps (NETs), and its formation and release, known as NETosis, may play a role in the initiation of thrombin generation (TG) in trauma. The objective of this study was to assess whether trauma patients, who develop symptomatic venous thromboembolism (VTE), have increased levels of plasma citrullinated histone H3 (CitH3) and accelerated TG kinetics. Methods: Patients presenting to a level I trauma center as trauma activations had samples collected within 12 h of time of injury, alongside healthy volunteers (HV). CitH3 was measured by enzyme-linked immunosorbent assay, and TG data were measured using a TG analyzer, comparing results between patients developing symptomatic VTE versus those who did not, within 90 days of injury. Data were expressed as median and quartiles (Q1, Q3), and tested using Wilcoxon rank-sum or Fisher’s exact test, or 1-sample test of Spearman’s correlation, P < 0.05 considered significant. Results: 39 trauma patient samples were analyzed (10 with and 29 without VTE), and compared to 15 HV samples. CitH3 levels in patients who developed VTE were significantly greater as compared to those who did not (12.8 ng/mL [7.1, 30.8]; 3.0 ng/mL [1.8,6.8], P = 0.024), with levels in both groups greater compared to HV (1.2 [0.3, 4.1], P = 0.003, P = 0.012), respectively. TG profiles were accelerated in patients developing VTE, with differences in peak height (337.6 nM [304.4, 356.0]; 231.8 nM [180.2, 281.8], P = 0.008), endogenous thrombin potential (1718.5 nM*min [1,500, 1794]; 1208.5 nM*min [1,072, 1,417], P = 0.003) and velocity index (213.2 nM/min [162.3, 260.5]; 124.3 nM/min [93.2, 223.1], P = 0.03), respectively. Conclusion: Trauma patients developing VTE exhibit increased NETosis, measured by increased CitH3 levels and accelerated TG early after injury, outlining an area for further understanding VTE after trauma.

Background Von Willebrand factor (VWF) is an acute phase reactant synthesized in the megakaryocytes and endothelial cells. VWF forms ultra-large multimers (ULVWF) which are cleaved by the metalloprotease ADAMTS-13, preventing spontaneous VWF–platelet interaction. After trauma, ULVWF is released into circulation as part of the acute phase reaction. We hypothesized that trauma patients would have increased levels of VWF and decreased levels of ADAMTS-13 and that these patients would have accelerated thrombin generation. Methods We assessed plasma concentrations of VWF antigen and ADAMTS-13 antigen, the Rapid Enzyme Assays for Autoimmune Diseases (REAADS) activity of VWF, which measure exposure of the platelet-binding A1 domain, and thrombin generation kinetics in 50 samples from 30 trauma patients and an additional 21 samples from volunteers. Samples were analyzed at 0 to 2 hours and at 6 hours from the time of injury. Data are presented as median (IQR) and Kruskal-Wallis test was performed between trauma patients and volunteers at both time points. Results REAADS activity was greater in trauma patients than volunteers both at 0 to 2 hours (190.0 (132.0–264.0) vs. 92.0 (71.0–114.0), p<0.002) and at 6 hours (167.5 (108.0–312.5.0) vs. 92.0 (71.0–114.0), p<0.001). ADAMTS-13 antigen levels were also decreased in trauma patients both at 0 to 2 hours (0.84 (0.51–0.94) vs. 1.00 (0.89–1.09), p=0.010) and at 6 hours (0.653 (0.531–0.821) vs. 1.00 (0.89–1.09), p<0.001). Trauma patients had accelerated thrombin generation kinetics, with greater peak height and shorter time to peak than healthy volunteers at both time points. Discussion Trauma patients have increased exposure of the VWF A1 domain and decreased levels of ADAMTS-13 compared with healthy volunteers. This suggests that the VWF burst after trauma may exceed the proteolytic capacity of ADAMTS-13, allowing circulating ULVWF multimers to bind platelets, potentially contributing to trauma-induced coagulopathy. Level of evidence Prospective case cohort study.