Identification of Fibrinogen as a Key Anti-Apoptotic Factor in Human Fresh Frozen Plasma for Protecting Endothelial Cells In Vitro

Major endothelial damage markers identified from hemadsorption filters derived from treated patients with septic shock - endoplasmic reticulum stress and bikunin may play a role

Introduction

In septic patients the damage of the endothelial barrier is decisive leading to circulatory septic shock with disseminated vascular coagulation, edema and multiorgan failure. Hemadsorption therapy leads to rapid resolution of clinical symptoms. We propose that the isolation of proteins adsorbed to hemadsorption devices contributes to the identification of mediators responsible for endothelial barrier dysfunction.

Material and methods

Plasma materials enriched to hemadsorption filters (CytoSorb®) after therapy of patients in septic shock were fractionated and functionally characterized for their effect on cell integrity, viability, proliferation and ROS formation by human endothelial cells. Fractions were further studied for their contents of oxidized nucleic acids as well as peptides and proteins by mass spectrometry.

Results

Individual fractions exhibited a strong effect on endothelial cell viability, the endothelial layer morphology, and ROS formation. Fractions with high amounts of DNA and oxidized DNA correlated with ROS formation in the target endothelium. In addition, defined proteins such as defensins (HNP-1), SAA1, CXCL7, and the peptide bikunin were linked to the strongest additive effects in endothelial damage.

Conclusion

Our results indicate that hemadsorption is efficient to transiently remove strong endothelial damage mediators from the blood of patients with septic shock, which explains a rapid clinical improvement of inflammation and endothelial function. The current work indicates that a combination of stressors leads to the most detrimental effects. Oxidized ssDNA, likely derived from mitochondria, SAA1, the chemokine CXCL7 and the human neutrophil peptide alpha-defensin 1 (HNP-1) were unique for their significant negative effect on endothelial cell viability. However, the strongest damage effect occurred, when, bikunin - cleaved off from alpha-1-microglobulin was present in high relative amounts (>65%) of protein contents in the most active fraction. Thus, a relevant combination of stressors appears to be removed by hemadsorption therapy which results in fulminant and rapid, though only transient, clinical restitution.

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.

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.

Fibrinogen inhibits microRNA-19b, a novel mechanism for repair of haemorrhagic shock-induced endothelial cell dysfunction

BACKGROUND

The benefits of plasma as an adjunct to the treatment of haemorrhagic shock are well established; however, the mechanism by which plasma modulates the endotheliopathy of trauma remains unclear. Our recent data demonstrated a novel role of microRNA-19b in post-haemorrhagic shock endothelial dysfunction via targeting of syndecan-1. Additionally, fibrinogen, as a key component of plasma or an isolated haemostatic protein, protects the endothelium by stabilizing syndecan-1. We therefore hypothesized that fibrinogen would inhibit microRNA-19b to mitigate the endotheliopathy of trauma in a murine model of haemorrhagic shock.

MATERIALS AND METHODS

C57BL/6J mice were subjected to haemorrhagic shock (mean arterial pressure 35±5 mmHg for 90 minutes) followed by resuscitation with lactated Ringer's, fresh frozen plasma, fibrinogen or no resuscitation. MicroRNA-19b and syndecan-1 mRNA were measured in lung tissue by qRT-PCR. Lungs were stained for histopathologic injury, and broncheoalveolar lavage was collected for protein as a permeability indicator.

RESULTS

Pulmonary microRNA-19b was increased after haemorrhagic shock and lactated Ringers, but reduced to sham levels by plasma and fibrinogen. Conversely, pulmonary syndecan-1 mRNA was downregulated by haemorrhagic shock and lactated Ringers, but returned to sham levels by plasma and fibrinogen. Plasma and fibrinogen-based resuscitation reduced lung injury compared to haemorrhagic shock and lactated Ringers while fibrinogen also reduced broncheoalveolar lavage protein.

DISCUSSION

We have demonstrated a novel mechanism by which fibrinogen, a key component of plasma and haemostatic agent, inhibits miR-19b, possibly by mitigating the endotheliopathy of trauma. Complete demonstration of the mechanism of fibrinogen inhibition of endotheliopathy via microRNA, however, remains to be elucidated. These findings support the early and empiric use of fibrinogen in post-haemorrhagic shock resuscitation.

Spray-dried plasma: A post-traumatic blood "bridge" for life-saving resuscitation

Massive bleeding remains a major source of morbidity and mortality worldwide. Recent studies have shed light on the pathophysiology of traumatic-induced coagulopathy and the central role of endotheliopathy. Transfusion therapy has changed dramatically in the last decade with use of red cells and plasma in a 1:1 ratio. The use of early transfusion increases the likelihood of a favorable outcome. Early intervention-preferably less than 60 min of injury-is a major factor in improved survival. Experience with dried plasma products-lyophilized or freeze-dried-in Europe and South Africa has demonstrated both safety and efficacy. Dry plasma products are not available in the United States but several products are in development. Spray-dried plasma contains clinically meaningful levels of coagulation activity and in vitro data suggest robust ability to generate thrombus. The decentralized, blood-center based manufacturing model of spray-dried plasma offers advantages for availability to meet routine and extraordinary demands.

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

BACKGROUND

Plasma has been shown to mitigate the endotheliopathy of trauma. Protection of the endothelium may be due in part to fibrinogen and other plasma-derived proteins found in cryoprecipitate; however, the exact mechanisms remain unknown. Clinical trials are underway investigating early cryoprecipitate administration in trauma. In this study, we hypothesize that cryoprecipitate will inhibit endothelial cell (EC) permeability in vitro and will replicate the ability of plasma to attenuate pulmonary vascular permeability and inflammation induced by hemorrhagic shock and trauma (HS/T) in mice.

METHODS

In vitro, barrier permeability of ECs subjected to thrombin challenge was measured by transendothelial electrical resistance. In vivo, using an established mouse model of HS/T, we compared pulmonary vascular permeability among mice resuscitated with (1) lactated Ringer's solution (LR), (2) fresh frozen plasma (FFP), or (3) cryoprecipitate. Lung tissue from the mice in all groups was analyzed for markers of vascular integrity, inflammation, and inflammatory gene expression via NanoString messenger RNA quantification.

RESULTS

Cryoprecipitate attenuates EC permeability and EC junctional compromise induced by thrombin in vitro in a dose-dependent fashion. In vivo, resuscitation of HS/T mice with either FFP or cryoprecipitate attenuates pulmonary vascular permeability (sham, 297 ± 155; LR, 848 ± 331; FFP, 379 ± 275; cryoprecipitate, 405 ± 207; p < 0.01, sham vs. LR; p < 0.01, LR vs. FFP; and p < 0.05, LR vs. cryoprecipitate). Lungs from cryoprecipitate- and FFP-treated mice demonstrate decreased lung injury, decreased infiltration of neutrophils and activation of macrophages, and preserved pericyte-endothelial interaction compared with LR-treated mice. Gene analysis of lung tissue from cryoprecipitate- and FFP-treated mice demonstrates decreased inflammatory gene expression, in particular, IL-1β and NLRP3, compared with LR-treated mice.

CONCLUSION

Our data suggest that cryoprecipitate attenuates the endotheliopathy of trauma in HS/T similar to FFP. Further investigation is warranted on active components and their mechanisms of action.

Endothelial Dysfunction is Associated With Increased Incidence, Worsened Severity, and Prolonged Duration of Acute Kidney Injury After Severe Trauma

INTRODUCTION

Nearly half of severely injured patients suffer acute kidney injury (AKI), but little is known about its pathogenesis or optimal management. We hypothesized that endothelial dysfunction, evidenced by elevated systemic soluble thrombomodulin (sTM) and syndecan-1, would be associated with higher incidence, worsened severity, and prolonged duration of AKI after severe trauma.

METHODS

A single-center cohort study of severely injured patients surviving ≥24 h from 2012 to 2016 was performed. Arrival plasma sTM and syndecan-1 were measured by ELISA. Outcomes included 7-day AKI incidence, stage, and prolonged AKI ≥2 days. The Kidney Disease Improving Global Outcomes guidelines were used for AKI diagnosis and staging. Univariate and multivariable analyses were performed.

RESULTS

Of 477 patients, 78% were male. Patients had a median age of 38 (interquartile ranges [IQR] 27-54) and injury severity score of 17 (IQR 10-26). AKI developed in 51% of patients. Those with AKI were older and displayed worse arrival physiology. Patients with AKI had higher plasma levels of syndecan-1 (median 34.9 ng/mL vs. 20.1 ng/mL) and sTM (6.5 ng/mL vs. 4.8 ng/mL). After adjustment, sTM and syndecan-1 were both associated with higher AKI incidence, worse AKI severity, and prolonged AKI duration. The strength and precision of the association of sTM and these outcomes were greater than those for syndecan-1. A sensitivity analysis excluding patients with AKI on arrival demonstrated the same relationship.

CONCLUSIONS

Elevated sTM and syndecan-1, indicating endothelial dysfunction, were associated with higher incidence, worsened severity, and prolonged duration of AKI after severe trauma. Treatments that stabilize the endothelium hold promise for AKI treatment in severely injured patients.

Contemporary resuscitation of hemorrhagic shock: What will the future hold?

Resuscitation of the critically ill patient with fluid and blood products is one of the most widespread interventions in medicine. This is especially relevant for trauma patients, as hemorrhagic shock remains the most common cause of preventable death after injury. Consequently, the study of the ideal resuscitative product for patients in shock has become an area of great scientific interest and investigation. Recently, the pendulum has swung towards increased utilization of blood products for resuscitation. However, pathogens, immune reactions and the limited availability of this resource remain a challenge for clinicians. Technologic advances in pathogen reduction and innovations in blood product processing will allow us to increase the safety profile and efficacy of blood products, ultimately to the benefit of patients. The purpose of this article is to review the current state of blood product based resuscitative strategies as well as technologic advancements that may lead to safer resuscitation.

Age-Dependent Association of Occult Hypoperfusion and Outcomes in Trauma

BACKGROUND

Occult hypoperfusion (OH), or global hypoperfusion with normal vital signs, is a risk factor for poor outcomes in elderly trauma patients. We hypothesized that OH is associated with worse outcomes than shock in both young and elderly trauma patients.

METHODS

We conducted a single-center cohort study of adult (16 years or older) trauma patients from 2016 to 2018 with base excess measured on arrival. Perfusion states were defined as shock if heart rate was >120 beats/min or systolic blood pressure was <90 mmHg; OH if base excess was < -2 mmol/L, heart rate was <120 beats/min, and systolic blood pressure was >90 mmHg; and normal for all others. Patients were stratified as young (younger than 55 years) or elderly (55 years or older). Bayesian regression was used to assess the relationship between arrival perfusion state and mortality or serious complication.

RESULTS

Of 3,126 included patients, 808 were elderly. Rates of shock (33% and 31%) and OH (25% and 23%) were similar in young and elderly patients, respectively. OH on arrival was associated with higher odds of mortality or serious complication than normal perfusion, regardless of age group. Compared with shock, OH was associated with an odds ratio of 1.21 (95% CI, 0.97 to 1.52, posterior probability 96%) for poor outcomes in elderly patients and an odds ratio of 0.52 (95% CI, 0.42 to 0.65, posterior probability <1%) for poor outcomes in younger patients. Findings were similar on sensitivity analysis, excluding shock patients with base excess ≥ -2 mmol/L.

CONCLUSIONS

In elderly but not younger patients, OH is associated with worse outcomes than shock. Although shock parameters might need to be redefined in elderly patients, more attention is necessary for the diagnosis and treatment of all hypoperfused states in this age group.