Anti-high-mobility group box-1 treatment strategies improve trauma-induced coagulopathy in a mouse model of trauma and shock.

BACKGROUND: Trauma-induced coagulopathy is associated with platelet dysfunction and contributes to early mortality after traumatic injury. Plasma concentrations of the damage molecule high-mobility group box-1 (HMGB-1) increase after trauma, which may contribute to platelet dysfunction. We hypothesised that inhibition of HMGB-1 with a monoclonal antibody (mAb) or with recombinant thrombomodulin (rTM) improves trauma-induced coagulopathy in a murine model of trauma and shock. METHODS: Male 129S2/SvPasOrlRJ mice were anaesthetised, mechanically ventilated, and randomised into five groups: (i) ventilation control (VENT), (ii) trauma/shock (TS), (iii) TS+anti-HMGB-1 mAb (TS+AB), (iv) TS+rTM (TS+TM), and (v) TS+anti-HMGB-1 mAb+rTM (TS+COMBI). Primary outcome was rotational thromboelastometry EXTEM. Secondary outcomes included tail bleeding time, platelet count, plasma HMGB-1 concentration, and platelet activation. RESULTS: Trauma and shock resulted in a hypocoagulable thromboelastometry profile, increased plasma HMGB-1, and increased platelet activation markers. TS+AB was associated with improved clot firmness after 5 min compared with TS (34 [33-37] vs 32 [29-34] mm; P=0.043). TS+COMBI was associated with decreased clot formation time (98 [92-125] vs 122 [111-148] s; P=0.018) and increased alpha angle (77 [72-78] vs 69 [64-71] degrees; P=0.003) compared with TS. TS+COMBI also reduced tail bleeding time compared with TS (P=0.007). The TS+TM and TS+COMBI groups had higher platelet counts compared with TS (P=0.044 and P=0.041, respectively). CONCLUSIONS: Inhibition of HMGB-1 early after trauma in a mouse model improves clot formation and strength, preserves platelet count, and decreases bleeding time.

The effect of shock duration on trauma-induced coagulopathy in a murine model.

BACKGROUND: Trauma-induced coagulopathy (TIC) is a life-threatening condition associated with high morbidity and mortality. TIC can present with different coagulation defects. In this study, the aim was to determine the effect of shock duration on TIC characteristics. We hypothesized that longer duration of shock leads to a more hypocoagulable rotational thromboelastometry (ROTEM) profile compared to a shorter duration of shock. METHODS: Male B57BL/6J(c) mice (n = 5-10 per group) were sedated and mechanically ventilated. Trauma was induced by bilateral lower limb fractures and crush injuries to the liver and small intestine. Shock was induced by blood withdrawals until a mean arterial pressure of 25-30 mmHg was achieved. Groups reflected trauma and shock for 30 min (TS30) and trauma and shock for 90 min (TS90). Control groups included ventilation only (V90) and trauma only (T90). RESULTS: Mice in the TS90 group had significantly increased base deficit compared to the V90 group. Mortality was 10% in the TS30 group and 30% in the TS90 group. ROTEM profile was more hypocoagulable, as shown by significantly lower maximum clot firmness (MCF) in the TS30 group (43.5 [37.5-46.8] mm) compared to the TS90 group (52.0 [47.0-53.0] mm, p = 0.04). ROTEM clotting time and parameters of clot build-up did not significantly differ between groups. CONCLUSIONS: TIC characteristics change with shock duration. Contrary to the hypothesis, a shorter duration of shock was associated with decreased maximum clotting amplitudes compared to a longer duration of shock. The effect of shock duration on TIC should be further assessed in trauma patients.

Plasma and rhADAMTS13 reduce trauma-induced organ failure by restoring the ADAMTS13-VWF axis.

Trauma-induced organ failure is characterized by endothelial dysfunction. The aim of this study was to investigate the role of von Willebrand factor (VWF) and its cleaving enzyme, ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motifs, member 13) in the occurrence of endothelial permeability and organ failure in trauma. In an observational study in a level-1 trauma center, 169 adult trauma patients with clinical signs of shock and/or severe injuries were included. Trauma was associated with low ADAMTS13 and high VWF antigen levels, thus generating an imbalance of ADAMTS13 to VWF. Patients who developed organ failure (23%) had greater ADAMTS13-to-VWF imbalances, persistently lower platelet counts, and elevated levels of high-molecular-weight VWF multimers compared with those without organ failure, suggesting microthrombi formation. To investigate the effect of replenishing low ADAMTS13 levels on endothelial permeability and organ failure using either recombinant human ADAMTS13 (rhADAMTS13) or plasma transfusion, a rat model of trauma-induced shock and transfusion was used. Rats in traumatic hemorrhagic shock were randomized to receive crystalloids, crystalloids supplemented with rhADAMTS13, or plasma transfusion. A 70-kDa fluorescein isothiocyanate-labeled dextran was injected to determine endothelial leakage. Additionally, organs were histologically assessed. Both plasma transfusion and rhADAMTS13 were associated with a reduction in pulmonary endothelial permeability and organ injury when compared with resuscitation with crystalloids, but only rhADAMTS13 resulted in significant improvement of a trauma-induced decline in ADAMTS13 levels. We conclude that rhADAMTS13 and plasma transfusion can reduce organ failure following trauma. These findings implicate the ADAMTS13-VWF axis in the pathogenesis of organ failure.

The use of cryopreserved platelets in a trauma-induced hemorrhage model.

BACKGROUND: Cryopreserved platelet products can be stored for years and are mainly used in military settings. Following thawing, cryopreserved platelets are activated, resulting in faster clot formation but reduced aggregation in vitro, rendering their efficacy in bleeding unknown. Also, concerns remain on the safety of these products. The aim was to investigate the efficacy and safety of cryopreserved platelets in a rat model of traumatic hemorrhage. STUDY DESIGN AND METHODS: After 1 hour of shock, rats (n = 13/group) were randomized to receive a balanced transfusion pack (1:1:1 red blood cell:plasma:platelet) made from syngeneic rat blood, containing either liquid stored platelets or cryopreserved platelets. Primary outcome was the transfusion volume required to obtain a mean arterial pressure (MAP) of 60 mmHg. Secondary outcomes were coagulation as assessed by thromboelastometry (ROTEM®) and organ failure as assessed by biochemistry and histopathology. RESULTS: The transfusion volume to obtain a MAP of 60 mmHg was lower in animals receiving cryopreserved platelets (5.4 [4.1-7.1] mL/kg) compared to those receiving liquid stored platelets (7.5 [6.4-8.5] mL/kg, p < 0.05). ROTEM® clotting times were shorter (45 [41-48] vs. 49 [45-53]sec, p < 0.05), while maximum clot firmness was slightly lower (68 [67-68] vs. 69 [69-71]mm, p < 0.01). Organ failure was similar in both groups. CONCLUSIONS: Use of cryopreserved platelets required less transfusion volume to reach a targeted MAP compared to liquid stored platelets, while organ injury was similar. These results provide a rationale for clinical trials with cryopreserved platelets in (traumatic) bleeding.