Cryoprecipitate attenuates the endotheliopathy of trauma in mice subjected to hemorrhagic shock and trauma

A machine learning-based Coagulation Risk Index predicts acute traumatic coagulopathy in bleeding trauma patients

BACKGROUND

Acute traumatic coagulopathy (ATC) is a well-described phenomenon known to begin shortly after injury. This has profound implications for resuscitation from hemorrhagic shock, as ATC is associated with increased risk for massive transfusion (MT) and mortality. We describe a large-data machine learning-based Coagulation Risk Index (CRI) to test the early prediction of ATC in bleeding trauma patients.

METHODS

Coagulation Risk Index was developed using continuous vital signs (VSs) available during the first 15 minutes after admission at a single trauma center over 4 years. Data to compute the CRI were derived from continuous features of photoplethymographic and electrocardiographic waveforms, oximetry values, and blood pressure trends. Two groups of patients at risk for ATC were evaluated: critical administration threshold and patients who received an MT. Acute traumatic coagulopathy was evaluated in separate models and defined as an international normalized ratio (INR) >1.2 and >1.5 upon arrival. The CRI was developed using 2 years of cases for training and 2 years for testing. The accuracy of the models is described by area under the receiver operator curve with 95% confidence intervals.

RESULTS

A total of 17,567 patients were available for analysis with continuous VS data, 52.8% sustained blunt injury, 30.2% were female, and the mean age was 44.6 years. The ability of CRI to predict ATC in critical administration threshold patients was excellent. The true positive and true negative rates were 95.6% and 88.3%, and 94.9% and 89.2% for INR >1.2 and INR >1.5, respectively. The CRI also demonstrated excellent accuracy in patients receiving MT; true positive and true negative rates were 92.8% and 91.3%, and 100% and 88.1% for INR >1.2 and INR >1.5, respectively.

CONCLUSION

Using continuous VSs and large-data machine learning capabilities, the CRI accurately predicts early ATC in bleeding patients. Clinical application may guide early hemostatic resuscitation. Extension of this technology into the prehospital setting could provide earlier treatment of ATC.

LEVEL OF EVIDENCE

Diagnostic Tests/Criteria; Level III.

Injury induced endotheliopathy: overview, diagnosis, and management

PURPOSE OF REVIEW

This review aims to examine recent advances in the understanding of injury-induced endotheliopathy and therapeutics to mitigate its development in critically injured patients.

RECENT FINDINGS

Clinical studies have clearly demonstrated that syndecan-1 ectodomains can be found in circulation after various types of trauma and injury and correlates with worse outcomes. As the mechanisms of endotheliopathy are better understood, pathologic hyperadhesive forms of von Willebrand factor, along with a relative deficiency of its cleaving enzyme, a disintegrin and metalloprotease with thrombospondin type I motifs, member 13 (ADAMTS13), have emerged as additional biomarkers. Therapeutics to date have focused primarily on the protective effects of fresh frozen plasma and its constituents to restore the glycocalyx. Human recombinant ADAMTS13 holds promise, as do synthetic variants of heparan sulfate and activated protein C, although all data to date are preclinical.

SUMMARY

Injury-induced endotheliopathy represents an important pathologic response to trauma. Key biomarkers, such as syndecan-1, can aid in the diagnosis, but testing is not yet available clinically. As the mechanisms of endotheliopathy are better understood, therapeutics are being identified and show promise. To date, plasma has been the most widely studied; however, like all therapeutics for injury-induced endotheliopathy, it has primarily been studied in the preclinical setting.

Regulation of vascular endothelial integrity by mesenchymal stem cell extracellular vesicles after hemorrhagic shock and trauma

BACKGROUND

Patients with hemorrhagic shock and trauma (HS/T) are vulnerable to the endotheliopathy of trauma (EOT), characterized by vascular barrier dysfunction, inflammation, and coagulopathy. Cellular therapies such as mesenchymal stem cells (MSCs) and MSC extracellular vesicles (EVs) have been proposed as potential therapies targeting the EOT. In this study we investigated the effects of MSCs and MSC EVs on endothelial and epithelial barrier integrity in vitro and in vivo in a mouse model of HS/T. This study addresses the systemic effects of HS/T on multiorgan EOT.

METHODS

In vitro, pulmonary endothelial cell (PEC) and Caco-2 intestinal epithelial cell monolayers were treated with control media, MSC conditioned media (CM), or MSC EVs in varying doses and subjected to a thrombin or hydrogen peroxide (H2O2) challenge, respectively. Monolayer permeability was evaluated with a cell impedance assay, and intercellular junction integrity was evaluated with immunofluorescent staining. In vivo, a mouse model of HS/T was used to evaluate the effects of lactated Ringer's (LR), MSCs, and MSC EVs on endothelial and epithelial intercellular junctions in the lung and small intestine as well as on plasma inflammatory biomarkers.

RESULTS

MSC EVs and MSC CM attenuated permeability and preserved intercellular junctions of the PEC monolayer in vitro, whereas only MSC CM was protective of the Caco-2 epithelial monolayer. In vivo, both MSC EVs and MSCs mitigated the loss of endothelial adherens junctions in the lung and small intestine, though only MSCs had a protective effect on epithelial tight junctions in the lung. Several plasma biomarkers including MMP8 and VEGF were elevated in LR- and EV-treated but not MSC-treated mice.

CONCLUSIONS

In conclusion, MSC EVs could be a potential cell-free therapy targeting endotheliopathy after HS/T via preservation of the vascular endothelial barrier in multiple organs early after injury. Further research is needed to better understand the immunomodulatory effects of these products following HS/T and to move toward translating these therapies into clinical studies.

Regulation of Vascular Endothelial Integrity by Mesenchymal Stem Cell Extracellular Vesicles after Hemorrhagic Shock and Trauma

BACKGROUND

Patients with hemorrhagic shock and trauma (HS/T) are vulnerable to the endotheliopathy of trauma (EOT), characterized by vascular barrier dysfunction, inflammation, and coagulopathy. Cellular therapies such as mesenchymal stem cells (MSCs) and MSC extracellular vesicles (EVs) have been proposed as potential therapies targeting the EOT. In this study we investigated the effects of MSCs and MSC EVs on endothelial and epithelial barrier integrity in vitro and in vivo in a mouse model of HS/T. This study addresses systemic effects of HS/T on multiorgan EOT in HS/T model.

METHODS

In vitro, pulmonary endothelial cell (PEC) and Caco-2 intestinal epithelial cell monolayers were treated with control media, MSC conditioned media (CM), or MSC EVs in varying doses and subjected to a thrombin or hydrogen peroxide (H2O2) challenge, respectively. Monolayer permeability was evaluated with a cell impedance assay, and intercellular junction integrity was evaluated with immunofluorescent staining. In vivo, a mouse model of HS/T was used to evaluate the effects of lactated Ringer's (LR), MSCs, and MSC EVs on endothelial and epithelial intercellular junctions in the lung and small intestine as well as on plasma inflammatory biomarkers.

RESULTS

MSC EVs and MSC CM attenuated permeability and preserved intercellular junctions of the PEC monolayer in vitro, whereas only MSC CM was protective of the Caco-2 epithelial monolayer. In vivo, both MSC EVs and MSCs mitigated the loss of endothelial adherens junctions in the lung and small intestine, though only MSCs had a protective effect on epithelial tight junctions in the lung. Several plasma biomarkers including MMP8 and VEGF were elevated in LR- and EV-treated but not MSC-treated mice.

CONCLUSIONS

In conclusion, MSC EVs could be a potential cell-free therapy targeting endotheliopathy after HS/T via preservation of the vascular endothelial barrier in multiple organs early after injury. Further research is needed to better understand the immunomodulatory effects of these products following HS/T and to move toward translating these therapies into clinical studies.

Impact of COVID status and blood group on complications in patients in hemorrhagic shock

Objective

Among critically injured patients of various blood groups, we sought to compare survival and complication rates between COVID-19-positive and COVID-19-negative cohorts.

Background

SARS-CoV-2 infections have been shown to cause endothelial injury and dysfunctional coagulation. We hypothesized that, among patients with trauma in hemorrhagic shock, COVID-19-positive status would be associated with increased mortality and inpatient complications. As a secondary hypothesis, we suspected group O patients with COVID-19 would experience fewer complications than non-group O patients with COVID-19.

Methods

We evaluated all trauma patients admitted 4/2020-7/2020. Patients 16 years or older were included if they presented in hemorrhagic shock and received emergency release blood products. Patients were dichotomized by COVID-19 testing and then divided by blood groups.

Results

3281 patients with trauma were evaluated, and 417 met criteria for analysis. Seven percent (29) of patients were COVID-19 positive; 388 were COVID-19 negative. COVID-19-positive patients experienced higher complication rates than the COVID-19-negative cohort, including acute kidney injury, pneumonia, sepsis, venous thromboembolism, and systemic inflammatory response syndrome. Univariate analysis by blood groups demonstrated that survival for COVID-19-positive group O patients was similar to that of COVID-19-negative patients (79 vs 78%). However, COVID-19-positive non-group O patients had a significantly lower survival (38%). Controlling for age, sex and Injury Severity Score, COVID-19-positive patients had a greater than 70% decreased odds of survival (OR 0.28, 95% CI 0.09 to 0.81; p=0.019).

Conclusions

COVID-19 status is associated with increased major complications and 70% decreased odds of survival in this group of patients with trauma. However, among patients with COVID-19, blood group O was associated with twofold increased survival over other blood groups. This survival rate was similar to that of patients without COVID-19.

THE NEUROENDOTHELIAL AXIS IN TRAUMATIC BRAIN INJURY: MECHANISMS OF MULTIORGAN DYSFUNCTION, NOVEL THERAPIES, AND FUTURE DIRECTIONS

ABSTRACT

Severe traumatic brain injury (TBI) often initiates a systemic inflammatory response syndrome, which can potentially culminate into multiorgan dysfunction. A central player in this cascade is endotheliopathy, caused by perturbations in homeostatic mechanisms governed by endothelial cells due to injury-induced coagulopathy, heightened sympathoadrenal response, complement activation, and proinflammatory cytokine release. Unique to TBI is the potential disruption of the blood-brain barrier, which may expose neuronal antigens to the peripheral immune system and permit neuroinflammatory mediators to enter systemic circulation, propagating endotheliopathy systemically. This review aims to provide comprehensive insights into the "neuroendothelial axis" underlying endothelial dysfunction after TBI, identify potential diagnostic and prognostic biomarkers, and explore therapeutic strategies targeting these interactions, with the ultimate goal of improving patient outcomes after severe TBI.

Effect of early hemostasis strategy on secondary post-traumatic sepsis in trauma hemorrhagic patients

INTRODUCTION

Fibrinogen and platelet, as the two main components of hemostatic resuscitation, are frequently administered in traumatic massive hemorrhage patients. It is reasonable to infer that they may have an impact on post-traumatic sepsis as more and more recognition of their roles in inflammation and immunity. This study aims to determine the association between the fibrinogen/platelet transfusion ratio during the first 24 h after trauma and the risk of the post- traumatic sepsis.

METHODS

We analyzed the data from the National Trauma Data Bank (NTDB). Subjects included the critically injured adult patients admitted to Level I/II trauma center from 2013 to 2017 who received fibrinogen and platelet supplementation and more than 10 units (about 4000 ml) packed red blood cells (pRBCs) during the first 24 h after trauma. Two parts of analyses were performed: (1) multivariable stepwise regression was used to determine the variables that influence the risk of post-traumatic sepsis; (2) propensity score matching (PSM), to compare the influences of different transfusion ratio between fibrinogen and platelet on the risk of sepsis and other outcomes after trauma.

RESULTS

8 features were screened out by bi-directional multivariable stepwise logistic regression to predict the post-traumatic sepsis. They are age, sex, BMI, ISSabdomen, current smoker, COPD, Fib4h/24h and Fib/PLT24h. Fib/PLT24h was negatively related to sepsis (p < 0.05). A total of 1601 patients were included in the PSM cohort and grouped by Fib/PLT24h = 0.025 according to the fitting generalized additive model (GAM) model curve. The incidence of sepsis was significantly decreased in the high Fib/PLT group [3.3 % vs 9.4 %, OR = 0.33, 95 %CI (0.17-0.60)]; the length of stay in ICU and mechanical ventilation were both shortened as well [8 (IQR 2.00,17.00) vs 9 (IQR 3.00,19.25), p = 0.006 and 4 (IQR 2.00,10.00) vs 5 (IQR 2.00,14.00), p = 0.003, respectively.

CONCLUSIONS

Early and sufficient supplementation of fibrinogen was a convenient way contribute to reduce the risk of sepsis after trauma.

Fibrinogen Fragment X Mediates Endothelial Barrier Disruption via Suppression of VE-Cadherin

INTRODUCTION

Major traumatic injury is associated with early hemorrhage-related and late-stage deaths due to multiple organ failure (MOF). While improvements to hemostatic resuscitation have significantly reduced hemorrhage-related deaths, the incidence of MOF among trauma patients remains high. Dysregulation of vascular endothelial cell (EC) barrier function is a central mechanism in the development of MOF; however, the mechanistic triggers remain unknown. Accelerated fibrinolysis occurs in a majority of trauma patients, resulting in high circulating levels of fibrin(ogen) degradation products, such as fragment X. To date, the relationship between fragment X and EC dysregulation and barrier disruption is unknown. The goal of this study was to determine the effects of fragment X on EC barrier integrity and expression of paracellular junctional proteins that regulate barrier function.

METHODS

Human lung microvascular endothelial cells (HLMVECs) were treated with increasing concentrations of fragment X (1, 10, and 100 μg/mL), and barrier function was monitored using the xCELLigence live-cell monitoring system. Quantitative PCR (qPCR) was performed to measure changes in EC expression of 84 genes. Immunofluorescent (IF) cytostaining was performed to validate qPCR findings.

RESULTS

Fragment X treatment significantly increased endothelial permeability over time (P < 0.05). There was also a significant reduction in VE-cadherin mRNA expression in fragment X-treated HLMVECs compared to control (P = 0.01), which was confirmed by IF staining.

CONCLUSIONS

Fragment X may induce EC hyperpermeability by reducing VE-cadherin expression. This suggests that a targeted approach to disrupting EC-fragment X interactions could mitigate EC barrier disruption, organ edema, and MOF associated with major trauma.

Early Fibrinogen Replacement to Treat the Endotheliopathy of Trauma: Novel Resuscitation Strategies in Severe Trauma

The authors provide a comprehensive review of the endothelial glycocalyx, the components that may be targeted to improve clinical outcomes, and the next steps for evaluation in human subjects.

Early lyophilized cryoprecipitate enhances the ADAMTS13/VWF ratio to reduce systemic endotheliopathy and lessen lung injury in a mouse multiple-trauma hemorrhage model

BACKGROUND

Recent studies in severely injured patients suggest an important role of von Willebrand Factor (VWF) and ADAMTS13 in the endotheliopathy of trauma (EoT). We hypothesized that the early use of cryoprecipitate would be effective as an endothelial protector by supplementing physiologic VWF and ADAMTS13 to reverse the EoT. We tested a pathogen-reduced lyophilized cryoprecipitate (LPRC) that could expedite the early administration of cryoprecipitate in the battlefield.

METHODS

A mouse multiple-trauma model with uncontrolled hemorrhage (UCH) from liver injury was utilized followed by hypotensive resuscitation (mean arterial pressure, 55-60) × 3 hours with lactated Ringer's (LR), fresh frozen plasma (FFP), conventional pathogen-reduced cryoprecipitate (CC), and LPRC. Blood was collected for measurement of syndecan-1, VWF, and ADAMTS13 by ELISA. Lungs were stained for histopathologic injury and syndecan-1 and bronchial alveolar lavage (BAL) fluid harvested for protein as an indicator of permeability. Statistical analysis was by ANOVA followed by Bonferroni correction.

RESULTS

Following multiple trauma and UCH, blood loss was similar across groups. Mean volume of resuscitation was higher in the LR group compared with the other resuscitation groups. Lung histopathologic injury, syndecan-1 immunostaining and BAL protein were higher with LR compared with resuscitation with FFP and CC, while LPRC further reduced BAL compared with FFP and CC. The ADAMTS13/VWF ratio was significantly lower in LR but improved with FFP and CC, comparable to shams while LPRC further increased this ratio.

CONCLUSION

The protective effects of CC and LPRC were comparable to FFP in ameliorating the EoT in our murine multiple trauma and UCH model. Lyophilized cryoprecipitate may also provide additional benefit by enhancing the ADAMTS13/VWF ratio. These data provide evidence of the safety and efficacy of LPRC and warrants further investigation for its potential application in military settings once approved for human administration.

Experimental Models of Traumatic Injuries: Do They Capture the Coagulopathy and Underlying Endotheliopathy Induced by Human Trauma?

Trauma-induced coagulopathy (TIC) is a major cause of morbidity and mortality in patients with traumatic injury. It describes the spectrum of coagulation abnormalities that occur because of the trauma itself and the body's response to the trauma. These coagulation abnormalities range from hypocoagulability and hyperfibrinolysis, resulting in potentially fatal bleeding, in the early stages of trauma to hypercoagulability, leading to widespread clot formation, in the later stages. Pathological changes in the vascular endothelium and its regulation of haemostasis, a phenomenon known as the endotheliopathy of trauma (EoT), are thought to underlie TIC. Our understanding of EoT and its contribution to TIC remains in its infancy largely due to the scarcity of experimental research. This review discusses the mechanisms employed by the vascular endothelium to regulate haemostasis and their dysregulation following traumatic injury before providing an overview of the available experimental in vitro and in vivo models of trauma and their applicability for the study of the EoT and its contribution to TIC.

Blood component resuscitative strategies to mitigate endotheliopathy in a murine hemorrhagic shock model

BACKGROUND

Resuscitation with plasma components has been shown to improve endotheliopathy induced by hemorrhagic shock, but the optimal resuscitation strategy to preserve the endothelial glycocalyx has yet to be defined. The aim of this study was to determine if resuscitation with lactated Ringer's (LR), whole blood (WB), packed red blood cells (RBCs), platelet-rich plasma (PRP), platelet poor plasma, balanced RBC:PRP (1:1), or day 14 (d14) RBC would best minimize endothelial damage following shock.

METHODS

Male C57BL/6 mice were hemorrhaged to a goal mean arterial pressure of 25 mm Hg for 1 hour. Unshocked sham mice served as controls. Mice were then resuscitated with equal volumes of LR, WB, RBC, PRP, platelet poor plasma, 1:1, or d14 RBC and then sacrificed at 1, 4, or 24 hours (n = 5). Serum was analyzed for syndecan-1, ubiquitin C-terminal hydrolase L1, and cytokine concentrations. Lungs underwent syndecan-1 immunostaining, and lung injury scores were calculated after hematoxylin and eosin. Proteolytic cleavage of the endothelial glycocalyx was assessed by serum matrix metalloprotease 9 levels.

RESULTS

Serum syndecan-1 and ubiquitin C-terminal hydrolase L1 levels were significantly increased following resuscitation with d14 RBC compared with other groups. Early elevation in lung syndecan-1 staining was noted in LR-treated mice, while d14 mice showed decreased staining compared with sham mice following shock. Lung injury scores were significantly elevated 4 hours after resuscitation with LR and d14 RBC compared with WB. Serum matrix metalloprotease 9 levels were significantly increased at 1 and 4 hours in d14 mice compared with sham mice. Systemic inflammation was increased in animals receiving LR, 1:1, or d14 RBC.

CONCLUSION

Resuscitation with WB following hemorrhagic shock reduces endothelial syndecan-1 shedding and mitigates lung injury. Aged RBC and LR fail to attenuate endothelial injury following hemorrhagic shock. Further research will be necessary to determine the effect of each of these resuscitative fluids in a hemorrhagic shock model with the addition of tissue injury.

Surgical Science and the Evolution of Critical Care Medicine

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

Raising the bar on fibrinogen: a retrospective assessment of critical hypofibrinogenemia in severely injured trauma patients

Objectives

Fibrinogen depletion may occur at higher levels than historically referenced. We evaluated hypofibrinogenemia and associated mortality and multiple organ failure (MOF) after severe injury.

Methods

Retrospective investigation including 417 adult patients with Injury Severity Score (ISS) >15. Demographics and injury characteristics were collected. Fibrinogen within 30 minutes of admission was described: <150 mg/dL, 150 mg/dL to 200 mg/dL and >200 mg/dL. Primary outcome: 28-day mortality. Secondary outcomes: 28-day MOF and blood product transfusion. Multivariable logistic regression model evaluated association of fibrinogen categories on risk of death, after controlling for confounding variables. Results presented as OR and 95% CIs.

Results

Fibrinogen <150 mg/dL: 4.8%, 150 mg/dL to 200 mg/dL: 18.2%, >200 mg/dL: 77.0%. 28-day mortality: 15.6%. Patients with <150 mg/dL fibrinogen had over fourfold increased 28-day mortality risk (OR: 4.9, 95% CI 1.53 to 15.7) after adjusting for age, ISS and admission Glasgow Coma Scale. Patients with lower fibrinogen were more likely to develop MOF (p=0.04) and receive larger red blood cell transfusion volumes at 3 hours and 24 hours (p<0.01).

Conclusions

Fibrinogen <150 mg/dL is significantly associated with increased 28-day mortality. Patients with fibrinogen <150 mg/dL were more likely to develop MOF and required increased administration of blood products. The optimal threshold for critically low fibrinogen, the association with MOF and subsequent fibrinogen replacement requires further investigation.

Level of evidence

Level III.

Use of Cold-Stored Whole Blood is Associated with Improved Mortality in Hemostatic Resuscitation of Major Bleeding: A Multicenter Study

OBJECTIVE

The aim of this study was to identify a mortality benefit with the use of whole blood as part of the resuscitation of bleeding trauma patients.

SUMMARY BACKGROUND DATA

Blood component therapy (BCT) is the current standard for resuscitating trauma patients, with whole blood (WB) emerging as the blood product of choice. We hypothesized that the use of WB versus BCT alone would result in decreased mortality.

METHODS

We performed a 14-center, prospective-observational study of trauma patients who received WB versus BCT during their resuscitation. We applied a generalized linear mixed-effects model with a random effect and controlled for age, sex, mechanism of injury (MOI), and injury severity score (ISS). All patients who received blood as part of their initial resuscitation were included. Primary outcome was mortality and secondary outcomes included AKI, DVT/PE, pulmonary complications, and bleeding complications.

RESULTS

A total of 1,623 (WB: 1,180(74%), BCT: 443(27%)) patients who sustained penetrating (53%) or blunt (47%) injury were included. Patients who received WB had a higher shock index (0.98 vs. 0.83), more comorbidities, and more blunt MOI (all P<0.05). After controlling for center, age, sex, MOI, and ISS, we found no differences in the rates of AKI, DVT/PE or pulmonary complications. WB patients were 9% less likely to experience bleeding complications and were 48% less likely to die than BCT patients (P<0.0001).

CONCLUSIONS

Compared with BCT, the use of WB was associated with a 48% reduction in mortality in trauma patients. Our study supports the use of WB use in the resuscitation of trauma patients.

Clinical Benefits of Early Concurrent Use of Cryoprecipitate and Plasma Compared With Plasma Only in Bleeding Trauma Patients

OBJECTIVES

The effectiveness of cryoprecipitate (Cryo) in trauma has not been well established; the benefits of Cryo might have been overestimated in previous studies since the difference in the total amount of administered clotting factors was not considered. We aimed to evaluate the benefits of the concurrent use of Cryo in combination with fresh frozen plasma (FFP) for bleeding trauma patients.

DESIGN

Retrospective cohort study.

SETTING

The American College of Surgeons Trauma Quality Improvement Program database between 2015 and 2019.

PATIENTS

Patients who received greater than or equal to 5 units of packed RBCs and at least 1 unit of FFP within the first 4 hours after arrival to a hospital were included and dichotomized according to whether Cryo was used within the first 4 hours of hospital arrival.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The outcomes of patients treated with Cryo and FFP were compared with those treated with FFP only using propensity score-matching analysis. The dose of administered clotting factors in each group was balanced. The primary outcome was inhospital mortality, and the secondary outcome was the occurrence rate of adverse events. A total of 24,002 patients (Cryo+FFP group: 6,018; FFP only group: 17,984) were eligible for analysis, of whom 4,852 propensity score-matched pairs were generated. Significantly lower inhospital mortality (1,959 patients [40.4%] in the Cryo+FFP group vs 2,142 patients [44.1%] in the FFP only group; odds ratio [OR], 0.86; 95% CI, 0.79-0.93) was observed in the Cryo+FFP group; no significant difference was observed in the occurrence rate of adverse events (1,857 [38.3%] vs 1,875 [38.6%]; OR, 1.02; 95% CI, 0.94-1.10). Several sensitivity analyses showed similar results.

CONCLUSIONS

Cryo use combined with FFP was significantly associated with reduced mortality in bleeding trauma patients. Future randomized controlled trials are warranted to confirm these results.

Mesenchymal stem cell extracellular vesicles mitigate vascular permeability and injury in the small intestine and lung in a mouse model of hemorrhagic shock and trauma

BACKGROUND

Hemorrhagic shock and trauma (HS/T)-induced gut injury may play a critical role in the development of multi-organ failure. Novel therapies that target gut injury and vascular permeability early after HS/T could have substantial impacts on trauma patients. In this study, we investigate the therapeutic potential of human mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC EVs) in vivo in HS/T in mice and in vitro in Caco-2 human intestinal epithelial cells.

METHODS

In vivo, using a mouse model of HS/T, vascular permeability to a 10-kDa dextran dye and histopathologic injury in the small intestine and lungs were measured among mice. Groups were (1) sham, (2) HS/T + lactated Ringer's (LR), (3) HS/T + MSCs, and (4) HS/T + MSC EVs. In vitro, Caco-2 cell monolayer integrity was evaluated by an epithelial cell impedance assay. Caco-2 cells were pretreated with control media, MSC conditioned media (CM), or MSC EVs, then challenged with hydrogen peroxide (H2O2).

RESULTS

In vivo, both MSCs and MSC EVs significantly reduced vascular permeability in the small intestine (fluorescence units: sham, 456 ± 88; LR, 1067 ± 295; MSC, 765 ± 258; MSC EV, 715 ± 200) and lung (sham, 297 ± 155; LR, 791 ± 331; MSC, 331 ± 172; MSC EV, 303 ± 88). Histopathologic injury in the small intestine and lung was also attenuated by MSCs and MSC EVs. In vitro, MSC CM but not MSC EVs attenuated the increased permeability among Caco-2 cell monolayers challenged with H2O2.

CONCLUSION

Mesenchymal stem cell EVs recapitulate the effects of MSCs in reducing vascular permeability and injury in the small intestine and lungs in vivo, suggesting MSC EVs may be a potential cell-free therapy targeting multi-organ dysfunction in HS/T. This is the first study to demonstrate that MSC EVs improve both gut and lung injury in an animal model of HS/T.

Targeting repair of the vascular endothelium and glycocalyx after traumatic injury with plasma and platelet resuscitation

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Endothelial glycocalyx shedding is a key instigator of the endotheliopathy of trauma.

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Plasma and platelet transfusions preserve vascular integrity in pre-clinical models.

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However, platelets may be less effective than plasma in preserving the glycocalyx.

Severely injured patients with hemorrhagic shock can develop endothelial dysfunction, systemic inflammation, and coagulation disturbances collectively known as the endotheliopathy of trauma (EOT). Shedding of the endothelial glycocalyx occurs early after injury, contributes to breakdown of the vascular barrier, and plays a critical role in the pathogenesis of multiple organ dysfunction, leading to poor outcomes in trauma patients. In this review we discuss (i) the pathophysiology of endothelial glycocalyx and vascular barrier breakdown following hemorrhagic shock and trauma, and (ii) the role of plasma and platelet transfusion in maintaining the glycocalyx and vascular endothelial integrity.

The Pathophysiology and Management of Hemorrhagic Shock in the Polytrauma Patient

The recognition and management of life-threatening hemorrhage in the polytrauma patient poses several challenges to prehospital rescue personnel and hospital providers. First, identification of acute blood loss and the magnitude of lost volume after torso injury may not be readily apparent in the field. Because of the expression of highly effective physiological mechanisms that compensate for a sudden decrease in circulatory volume, a polytrauma patient with a significant blood loss may appear normal during examination by first responders. Consequently, for every polytrauma victim with a significant mechanism of injury we assume substantial blood loss has occurred and life-threatening hemorrhage is progressing until we can prove the contrary. Second, a decision to begin damage control resuscitation (DCR), a costly, highly complex, and potentially dangerous intervention must often be reached with little time and without sufficient clinical information about the intended recipient. Whether to begin DCR in the prehospital phase remains controversial. Furthermore, DCR executed imperfectly has the potential to worsen serious derangements including acidosis, coagulopathy, and profound homeostatic imbalances that DCR is designed to correct. Additionally, transfusion of large amounts of homologous blood during DCR potentially disrupts immune and inflammatory systems, which may induce severe systemic autoinflammatory disease in the aftermath of DCR. Third, controversy remains over the composition of components that are transfused during DCR. For practical reasons, unmatched liquid plasma or freeze-dried plasma is transfused now more commonly than ABO-matched fresh frozen plasma. Low-titer type O whole blood may prove safer than red cell components, although maintaining an inventory of whole blood for possible massive transfusion during DCR creates significant challenges for blood banks. Lastly, as the primary principle of management of life-threatening hemorrhage is surgical or angiographic control of bleeding, DCR must not eclipse these definitive interventions.