Platelet dysfunction after trauma: From mechanisms to targeted treatment

Progress in chitosan/essential oil/ZnO nanobiocomposites fabrication for wound healing applications: A review

The development of therapeutic agents for wound healing is a key research area that focuses on coagulopathy and hospitalization. Wound healing involves various signaling pathways, the immune system, blood flow, and various cell types with urgent demands for agents that enhance cellular signaling, collagen deposition, neovascularization, and antimicrobial activity while minimizing scarring. Chitosan (CS) and zinc oxide (ZnO) exhibit synergistic properties that eliminate infection during treatment. Chitosan functions as a binding agent, influencing cellular responses to therapeutic-free products like essential oils (EOs). Interest in wound healing is growing due to nanomaterials, including metal and metal-oxide nanoparticles, which stimulate cellular proliferation, blood vessel formation, and possess anti-inflammatory properties. CS, EOs, and ZnO-NPs promoted wound healing through synergistic effects. Chitosan promotes clotting, combats bacteria, and aids tissue repair. Essential oils, like tea tree oil, provide antimicrobial, anti-inflammatory, and antioxidant benefits. ZnO-NPs enhance antibacterial action, angiogenesis, and collagen synthesis with low toxicity. Together, they form advanced dressings using chitosan as a scaffold, EOs providing bioactivity, and ZnO-NPs offering nanotechnology-driven efficacy. This combination accelerates healing, combats resistant pathogens, and supports chronic wound care using sustainable materials. This review examines the methods for creating hybrid materials using chitosan, EOs, and ZnO-NPs for skin regeneration.

Microfluidic transection injury and high-shear thrombus formation demonstrate increased hemostatic efficacy of cold-stored platelets and in vitro resuscitation in induced coagulopathy models

Hemostatic resuscitation is an essential aspect of treating traumatic bleeding. Trauma-induced coagulopathy is a multifactorial disorder that can lead to increased transfusion requirements. However, little is known about the interplay between coagulopathies and stored blood products used for hemostatic resuscitation, which themselves acquire dysfunction in the form of a storage lesion. Physiologically relevant models can aid in the study of trauma and hemostatic resuscitation by incorporating important aspects such as biological surfaces and flow regimes that mimic injury. This study aims to evaluate the contribution of platelet products under varying storage conditions in coagulopathic states. This study utilized microfluidic platforms of high shear, a flow regime relevant to injury, including a stenotic straight channel and a severe transected vessel injury device. Apheresis platelet products were collected from healthy volunteers, stored at room temperature (RT) or cold-stored (CS) (1°C-6°C), and tested for product cell count and intrinsic product function in a high-shear stenotic microfluidic device across storage days (D2, D5, and D7 for RT; D2, D5, D7, D14, and D21 for CS). Hemostatic resuscitation efficacy of products was assessed using induced coagulopathy models of dilution and thrombocytopenia (TP). In vitro hemostatic resuscitation was assessed in both the stenotic straight channel for kinetic platelet contributions and the transected-vessel injury device, using blood loss and clot composition as endpoints. CS products conserved inherent function despite decreasing platelet counts through storage D7. When mixed with coagulopathic blood, D2 RT products did not show hemostatic benefit in the dilutional coagulopathy (DC) model. However, both D2 RT and CS showed hemostatic benefits in the thrombocytopenia model. CS products (D5 and D7) also showed an enhanced ability to recruit recipient platelets in the thrombocytopenia model compared to RT. Overall, this study highlights disparate responses associated with product storage duration and temperature, indicating the need to further evaluate hemostatic resuscitation efficacy under flow in pathologically relevant models to guide transfusion practices.

Experimental and Mathematical Model of Platelet Hemostasis Kinetics

Upon activation, platelets undergo rapid phenotypic transitions to maintain hemostasis, yet the kinetics governing these transitions remain poorly quantified. We present an integrated experimental and mathematical model describing platelet transitions between resting, activated, aggregating, inhibited, and exhausted phenotypes, determined by experiment rate constants for these reactions. Theoretical simulations of platelet transitions accurately describe the independently determined experimental read-out. Platelet aggregation under the conditions used directly correlates with the activation of αIIbβ3 integrins, demonstrating that the parameters of platelet aggregation achieved by the laser diffraction technique can be used for the evaluation of the rapid activation and deactivation kinetics of αIIbβ3 integrins. We demonstrate that platelet desensitization occurs at multiple activation stages, with distinct kinetic profiles for shape change and integrin deactivation. We also show that even 5 s of receptor-mediated PKA activation (iloprost) is sufficient for a complete inhibition of ADP-induced platelet aggregation. However, when iloprost was added after platelet stimulation by ADP, platelet activation was not fully inhibited, and after 180 s, aggregation became irreversible. The presented data help to understand the mechanisms of platelet transition between different phenotypes. The model effectively characterizes key physiological phenotypes and can serve as a modular framework for integration into more comprehensive models.

The Role of Platelet Dysfunctions in the Pathogenesis of the Hemostatic-Coagulant System Imbalances

Platelet dysfunction plays a critical role in the pathogenesis of various disorders affecting the hemostatic-coagulant system. This review aims to explore the mechanisms by which platelet dysfunctions contribute to the disruption of hemostasis, leading to an increased risk of both thrombosis and bleeding. Platelets, traditionally known for their role in clot formation, can exhibit altered functionality under pathological conditions such as cardiovascular diseases, metabolic disorders, and autoimmune diseases, impacting their interaction with coagulation factors and vascular endothelium. The review discusses the molecular and cellular mechanisms underlying platelet dysfunction, including aberrations in platelet activation, aggregation, and secretion. It also highlights the interplay between platelets and other components of the coagulation cascade, such as fibrinogen and clotting factors, in maintaining vascular integrity. Moreover, the review examines clinical implications, including how platelet dysfunction can be a contributing factor in conditions like deep vein thrombosis, stroke, and disseminated intravascular coagulation (DIC). Finally, current therapeutic approaches targeting platelet dysfunctions, including antiplatelet agents and emerging therapies, are reviewed to provide insights into potential strategies for managing fluid-coagulation system imbalances. This review underscores the importance of a comprehensive understanding of platelet dysfunction to improve diagnosis and treatment of hemostatic disorders.

High-dimensional analysis of injured patients reveals distinct circulating proteomic profiles in plasma vs. whole blood resuscitation

Early blood product resuscitation is often essential for optimal trauma care. However, the effects of different products on the underlying trauma-induced coagulopathy and immune dysfunction are not well described. Here, we use high-dimensional analysis and causal modeling in a longitudinal study to explore the circulating proteomic response to plasma as a distinct component versus low-titer O whole blood (LTOWB), which contains plasma. We highlight the differential impacts of plasma and LTOWB on immune mediator levels and the distinct capacity of plasma to modulate coagulation by elevating fibrinogen and factor XIII and reducing platelet factor 4. A higher proportion of plasma in prehospital resuscitation is associated with improved admission time coagulation parameters in patients with severe shock and elevated brain injury markers and reduced post-admission transfusion volumes in those suffering from traumatic brain injury (TBI) and blunt injury. While LTOWB offers broad hemostatic benefits, our findings demonstrate specific advantages of plasma and support individualized transfusion strategies.

HMGB-1 as a predictor of major bleeding requiring activation of a massive transfusion protocol in severe trauma

Massive bleeding causes approximately 50% of deaths in patients with major trauma. Most patients die within 6 h of injury, which is preventable in at least 10% of cases. For these patients, early activation of the massive transfusion protocol (MTP) is a critical survival factor. With severe trauma, high-mobility group box 1 (HMGB-1, i.e., amphoterin) is released into the blood, and its levels correlate with the development of a systemic inflammatory response, traumatic coagulopathy, and fibrinolysis. Previous work has shown that higher levels of HMGB-1 are associated with a higher use of red blood cell transfusions. We conducted a retrospective analysis of previous prospective single-center study to assess the value of admission HMGB-1 levels in predicting activation of MTP in the emergency department. From July 11, 2019, to April 23, 2022, a total of 104 consecutive adult patients with severe trauma (injury severity score > 16) were enrolled. A blood sample was taken at admission, and HMGB-1 was measured. MTP activation in the emergency department was recorded in the study documentation. The total amount of blood products and fibrinogen administered to patients within 6 h of admission was monitored. Among those patients with massive bleeding requiring MTP activation, we found significantly higher levels of HMGB-1 compared to patients without MTP activation (median [interquartile range]: 84.3 µg/L [34.2-145.9] vs. 21.1 µg/L [15.7-30.4]; p < 0.001). HMGB-1 level showed good performance in predicting MTP activation, with an area under the receiver operating characteristic curve of 0.84 (95% CI 0.75-0.93) and a cut-off value of 30.55 µg/L. HMGB-1 levels correlated significantly with the number of red blood cell units (rs [95% CI] 0.46 [0.28-0.61]; p < 0.001), units of fresh frozen plasma (rs 0.46 [0.27-0.61]; p < 0.001), platelets (rs 0.48 [0.30-0.62]; p < 0.001), and fibrinogen (rs 0.48 [0.32-0.62]; p < 0.001) administered in the first 6 h after hospital admission. Admission HMGB-1 levels reliably predict severe bleeding requiring MTP activation in the emergency department and correlate with the amount of blood products and fibrinogen administered during the first 6 h of hemorrhagic shock resuscitation.Trial registration: NCT03986736. Registration date: June 4, 2019.

High-Dimensional Single-Cell Mass Cytometry Demonstrates Differential Platelet Functional Phenotypes in Infants With Congenital Heart Disease

BACKGROUND

Congenital heart disease (CHD) is a group of complex heart defects associated with hematologic abnormalities, including increased risk of thrombotic and bleeding events. Past studies have observed evidence of platelet hyperreactivity, while other studies showed decreased platelet activation in patients with CHD. The goal of this study was to develop a mass spectrometry approach to characterize single platelets in infants with CHD and identify potential etiology for such discrepant results.

METHODS

We enrolled 19 infants with CHD along with 21 non-CHD controls at Yale New Haven Children's Heart Center. A single-cell high-dimensional mass cytometry method was developed to quantitatively interrogate platelet surface markers in whole blood. Additionally, plasma cytokine analysis was performed through a multiplexed panel of 52 vascular and inflammatory markers to assess for platelet releasates.

RESULTS

We found that infants with CHD had significant differences in platelet activation and functional markers by mass cytometry compared with non-CHD controls. Based on cell surface markers, we classified the platelets into 8 subpopulations (P0 to P7). Distinct subpopulations of platelets (P1, P4, and P5) exhibiting decreased aggregatory phenotype but altered secretory phenotypes were also identified and found to be more abundant in the blood of infants with CHD. Electron microscopy identified increased proportion of hypogranular platelets in CHD. Moreover, cytokine analysis demonstrated an overall increase in plasma cytokines and biomarkers in CHD, including IL (interleukin)-6, IL-8, IL-27, RANTES (regulated upon activation, normal T cell expressed and secreted), and VWF (von Willebrand factor), which are expressed in platelet granules and can be released upon activation.

CONCLUSIONS

We developed a robust mass cytometry approach to identify platelet phenotypic heterogeneity. Infants with CHD had alterations in distinct subpopulations of platelets with overall reduced aggregatory phenotype and secretory dysfunction. These findings suggest that platelets in infants with CHD may be exhausted due to persistent stimulation and may explain both bleeding and thrombotic vascular complications associated with CHD.

Platelet Contribution and Endothelial Activation and Stress Index-Potential Mortality Predictors in Traumatic Brain Injury

Coagulopathy and traumatic brain injury (TBI) are complexly intertwined. In isolated TBI, coagulopathy may contribute to hemorrhagic lesion development, progression, or recurrence, as it may lead to a particular pattern of coagulopathy called TBI-induced coagulopathy (TBI-IC). We performed a retrospective and descriptive evaluation of 63 patients admitted to the Emergency Clinical Hospital Bucharest with the diagnosis of moderate/severe brain injury. In addition to demographic data, all included patients had a complete paraclinical evaluation that included rotational thromboelastometric (ROTEM) blood-clot analysis. The platelet component (PLTEM) and the endotheliopathy activation and stress index score (EASIX) were calculated. These parameters were presented comparatively according to survival at 30 days and helped define the two study groups: survivors and non-survivors at 30 days. The contribution of platelets to clot strength is derived from maximum clot elasticity (MCE) and maximum clot firmness (MCF). MCE is defined as (MCF × 100)/(100 - MCF), and PLTEM is defined as EXTEM MCE-FIBTEM MCE. EASIX is a novel biomarker recently studied in TBI patients, calculated according to the following formula: lactate dehydrogenase (U/L) × creatinine (mg/dL)/platelets (109 cells/L). Regarding the demographic data, there were no significant differences between the survivors and non-survivors. All ROTEM parameters related to clot amplitude (A5, A10, A20, MCF in EXTEM and FIBTEM channels) were higher in the group of patients who survived. Also, PLTEM was decreased in the group of deceased patients (89.71 ± 22.86 vs. 132.3 ± 16.56 p < 0.0001). The cut-off point determined with the ROC curve is 114.10, with a sensitivity of 94.74% and a specificity of 93.18%, for the detection of the negative prognosis (death at 30 days). The EASIX score was significantly higher in the patients who survived the traumatic event, with a median difference value of 1.15 (p < 0.0001). The ROC analysis of this biomarker highlights a cut-off point of 2.12, with a sensitivity of 88.64% and a specificity of 94.74% (AUC = 0.95, p < 0.0001), for the prediction of mortality. The comparative analysis of the two studied markers was performed using the Cox proportional hazard ratio and highlighted the greater influence that PLTEM has on survival time (b value = -0.05, p < 0.0001) compared to EASIX (b value = 0.49, p = 0.0026). The present retrospective study indicates the potential of the TBI-IC reflecting parameters PLTEM and EASIX as markers of mortality prognosis. Larger prospective studies are needed to confirm their combined prognostic value and use in decision-making and reduction in the burden of disease by adequate allocation of resources in a personalized and timely manner.

Immature platelet dynamics are associated with clinical outcomes after major trauma

BACKGROUND

Major trauma results in dramatic changes in platelet behavior. Newly formed platelets are more reactive than older platelets, but their contributions to hemostasis and thrombosis after severe injury have not been previously evaluated.

OBJECTIVES

To determine how immature platelet metrics and plasma thrombopoietin relate to clinical outcomes after major injury.

METHODS

A prospective observational cohort study was performed in adult trauma patients. Platelet counts and the immature platelet fraction (IPF) were measured at admission and 24 hours, 72 hours, and 7 days after injury. Thromboelastometry was performed at admission. Plasma thrombopoietin, c-Mpl, and GPIbα were quantified in a separate cohort. The primary outcome was in-hospital mortality; secondary outcomes were venous thromboembolic events and multiple organ dysfunction syndrome (MODS).

RESULTS

On admission, immature platelet counts (IPCs) were significantly lower in nonsurvivors (n = 40) than in survivors (n = 236; 7.3 × 109/L vs 10.6 × 109/L; P = .009), but IPF did not differ. Similarly, impaired platelet function on thromboelastometry was associated with lower admission IPC (9.1 × 109/L vs 11.9 × 109/L; P < .001). However, at later time points, we observed significantly higher IPF and IPC in patients who developed venous thromboembolism (21.0 × 109/L vs 11.1 × 109/L; P = .02) and prolonged MODS (20.9 × 109/L vs 11 × 109/L; P = .003) than in those who did not develop complications. Plasma thrombopoietin levels at admission were significantly lower in nonsurvivors (P < .001), in patients with MODS (P < .001), and in those who developed venous thromboembolism (P = .04).

CONCLUSION

Lower levels of immature platelets in the acute phase after major injury are associated with increased mortality, whereas higher immature platelet levels at later time points may predispose to thrombosis and MODS.

Blood Transfusion for Major Trauma in Emergency Department

Severe bleeding is the leading cause of death in patients with major trauma admitted to the emergency department. It is estimated that about 50% of deaths happen within a few minutes of the traumatic event due to massive hemorrhage; 30% of deaths are related to neurological dysfunction and typically happen within two days of trauma; and approximately 20% of patients died of multiorgan failure and sepsis within days to weeks of the traumatic event. Over the past ten years, there has been an increased understanding of the underlying mechanisms and pathophysiology associated with traumatic bleeding leading to improved management measures. Traumatic events cause significant tissue damage, with the potential for severe blood loss and the release of cytokines and hormones. They are responsible for systemic inflammation, activation of fibrinolysis pathways, and consumption of coagulation factors. As the final results of this (more complex in real life) cascade, patients can develop tissue hypoxia, acidosis, hypothermia, and severe coagulopathy, resulting in a rapid deterioration of general conditions with a high risk of mortality. Prompt and appropriate management of massive bleeding and coagulopathy in patients with trauma remains a significant challenge for emergency physicians in their daily clinical practice. Our review aims to explore literature studies providing evidence on the treatment of hemorrhage with blood support in patients with trauma admitted to the Emergency Department with a high risk of death. Advances in blood transfusion protocols, along with improvements in other resuscitation strategies, have become one of the most important issues to face and a key topic of recent clinical research in this field.

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.

Severe Trauma-Induced Coagulopathy: Molecular Mechanisms Underlying Critical Illness

Trauma remains one of the leading causes of death in adults despite the implementation of preventive measures and innovations in trauma systems. The etiology of coagulopathy in trauma patients is multifactorial and related to the kind of injury and nature of resuscitation. Trauma-induced coagulopathy (TIC) is a biochemical response involving dysregulated coagulation, altered fibrinolysis, systemic endothelial dysfunction, platelet dysfunction, and inflammatory responses due to trauma. The aim of this review is to report the pathophysiology, early diagnosis and treatment of TIC. A literature search was performed using different databases to identify relevant studies in indexed scientific journals. We reviewed the main pathophysiological mechanisms involved in the early development of TIC. Diagnostic methods have also been reported which allow early targeted therapy with pharmaceutical hemostatic agents such as TEG-based goal-directed resuscitation and fibrinolysis management. TIC is a result of a complex interaction between different pathophysiological processes. New evidence in the field of trauma immunology can, in part, help explain the intricacy of the processes that occur after trauma. However, although our knowledge of TIC has grown, improving outcomes for trauma patients, many questions still need to be answered by ongoing studies.