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.

ABSTRACT Background: Inorganic polyphosphate (polyP) is a procoagulant polyanion. We assessed the impact of polyP inhibition on thrombin generation after trauma using the novel polyP antagonists, macromolecular polyanion inhibitor 8 (MPI 8), and universal heparin reversal agent 8 (UHRA-8). Methods: Plasma thrombin generation (calibrated automated thrombogram, CAT), in 56 trauma patients and 39 controls +/− MPI 8 and UHRA-8 (50 μg/mL), was expressed as lag time (LT, minutes), peak height (PH, nM), and time to peak (ttPeak, minutes), with change in LT (ΔLT) and change in ttPeak (ΔttPeak) quantified. Results expressed in median and quartiles [Q1, Q3], Wilcoxon matched-pairs testing, P < 0.05 significant. Results: Trauma patients had greater baseline PH than controls (182.9 [121.0, 255.2]; 120.5 [62.1, 174.8], P < 0.001). MPI 8 treatment prolonged LT and ttPeak in trauma (7.20 [5.88, 8.75]; 6.46 [5.45, 8.93], P = 0.020; 11.28 [8.96, 13.14]; 11.00 [8.95, 12.94], P = 0.029) and controls (7.67 [6.67, 10.50]; 6.33 [5.33, 8.00], P < 0.001; 13.33 [11.67, 15.33]; 11.67 [10.33, 13.33], P < 0.001). UHRA-8 treatment prolonged LT and ttPeak and decreased PH in trauma (9.09 [7.45, 11.33]; 6.46 [5.45, 8.93]; 14.02 [11.78, 17.08]; 11.00 [8.95, 12.94]; 117.4 [74.5, 178.6]; 182.9 [121.0, 255.2]) and controls (9.83 [8.00, 12.33]; 6.33 [5.33, 8.00]; 16.67 [14.33, 20.00]; 11.67 [10.33, 13.33]; 55.3 [30.2, 95.9]; 120.5 [62.1, 174.8]), all P < 0.001. Inhibitor effects were greater for controls (greater ΔLT and ΔttPeak for both inhibitors, P < 0.001). Conclusion: PolyP inhibition attenuates thrombin generation, though to a lesser degree in trauma than in controls, suggesting that polyP contributes to accelerated thrombin generation after trauma.

ABSTRACT Introduction: Neutrophil extracellular traps (NETs) trigger thrombin generation. We aimed to characterize the effects of deoxyribonuclease (DNAse) on NET components (cell-free DNA [cfDNA] and histones) and thrombin generation after trauma. Methods: Citrated plasma samples were collected from trauma patients and healthy volunteers. Thrombin generation (calibrated automated thrombogram) was measured as lag time (LT, in minutes), peak height (in nM), and time to peak thrombin generation (in minutes). Citrullinated histone 3 (CitH3) and 4 (CitH4) were measured by enzyme-linked immunosorbent assay; cfDNA by PicoGreen (all in nanograms per milliliter). Samples analyzed +/− DNAse (1,000 U/mL). Results expressed as median and quartiles [Q1, Q3], Wilcoxon testing, P < 0.05 significant. Results: We enrolled 46 patients (age, 48 [31, 67] years; 67% male) and 21 volunteers (age, 45 [28, 53] years; 43% male). Deoxyribonuclease treatment of trauma plasma led to shorter LT (3.11 [2.67, 3.52] min; 2.93 [2.67, 3.19] min), shorter time to peak thrombin generation (6.00 [5.30, 6.67] min; 5.48 [5.00, 6.00] min), greater peak height (273.7 [230.7, 300.5] nM; 288.7 [257.6, 319.2] nM), decreased cfDNA (576.9 [503.3, 803.1] ng/mL; 456.0 [393.5, 626.7] ng/mL), decreased CitH3 (4.54 [2.23, 10.01] ng/mL; 3.59 [1.93, 7.98] ng/mL), and increased H4 (1.30 [0.64, 6.36] ng/mL; 1.75 [0.83, 9.67] ng/mL), all P < 0.001. The effect of DNAse was greater on trauma patients as compared with volunteers for LT (ΔLT, −0.21 vs. −0.02 min, P = 0.007), cfDNA (ΔcfDNA −133.4 vs. −84.9 ng/mL, P < 0.001), and CitH3 (ΔCitH3, –0.65 vs. −0.11 ng/mL, P = 0.004). Conclusion: Deoxyribonuclease treatment accelerates thrombin generation kinetics in trauma patient samples as compared with healthy volunteers. These findings suggest that NETs may contribute to the hypercoagulable state observed in trauma patients.

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.

ABSTRACT Background: Damage-associated molecular patterns (DAMPs) stimulate endothelial syndecan-1 shedding and neutrophil extracellular traps (NET) formation. The role of NETs in trauma and trauma-induced hypercoagulability is unknown. We hypothesized that trauma patients with accelerated thrombin generation would have increased NETosis and syndecan-1 levels. Methods: In this pilot study, we analyzed 50 citrated plasma samples from 30 trauma patients at 0 h (n = 22) and 6 h (n = 28) from time of injury (TOI) and 21 samples from healthy volunteers, for a total of 71 samples included in analysis. Thrombin generation was quantified using calibrated automated thrombogram (CAT) and reported as lag time (LT), peak height (PH), and time to peak (ttPeak). Nucleosome calibrated (H3NUC) and free histone standardized (H3Free) ELISAs were used to quantify NETs. Syndecan-1 levels were quantified by ELISA. Results are presented as median [interquartile range] and Spearman rank correlations. Results: Plasma levels of H3NUC were increased in trauma patients as compared with healthy volunteers both at 0 h (89.8 ng/mL [35.4, 180.3]; 18.1 ng/mL [7.8, 37.4], P = 0.002) and at 6 h (86.5 ng/mL [19.2, 612.6]; 18.1 ng/mL [7.8, 37.4], P = 0.003) from TOI. H3Free levels were increased in trauma patients at 0 h (5.74 ng/mL [3.19, 8.76]; 1.61 ng/mL [0.66, 3.50], P = 0.002) and 6 h (5.52 ng/mL [1.46, 11.37]; 1.61 ng/mL [0.66, 3.50], P = 0.006). Syndecan-1 levels were greater in trauma patients (4.53 ng/mL [3.28, 6.28]; 2.40 ng/mL [1.66, 3.20], P < 0.001) only at 6 h from TOI. H3Free and syndecan-1 levels positively correlated both at 0 h (0.376, P = 0.013) and 6 h (0.583, P < 0.001) from TOI. H3NUC levels and syndecan-1 levels were positively correlated at 6 h from TOI (0.293, P = 0.041). TtPeak correlated inversely to H3 NUC (−0.358, P = 0.012) and syndecan-1 levels (−0.298, P = 0.038) at 6 h from TOI. Conclusions: Our pilot study demonstrates that trauma patients have increased NETosis, measured by H3NUC and H3Free levels, increased syndecan-1 shedding, and accelerated thrombin generation kinetics early after injury.