Endotoxemia Following Multiple Trauma: Risk Factors and Prognostic Implications

Negative Factors Influencing Multiple-Trauma Patients

BACKGROUND AND OBJECTIVES

This study aimed to assess the impact and predicted outcomes of patients with multiple trauma by identifying the prevalence of trauma sustained and associated complications.

MATERIALS AND METHODS

This retrospective cohort study focused on individual characteristics of patients with multiple trauma admitted to our County Emergency Hospital. The final table centralized the characteristics of 352 subjects aged between 3 and 93 years who presented with multiple trauma from 2015 to 2021. Inclusion criteria for this study were the presence of multiple trauma, intervention times, mentioned subjects' ages, and types of multiple trauma.

RESULTS

Patients with multiple trauma face an increased risk of mortality due to the underlying pathophysiological response. Factors that can influence the outcomes of multiple-trauma patients include the severity of the initial injury, the number of injuries sustained, and the location of injuries.

CONCLUSION

The first 60 min after trauma, known as the "golden hour," is crucial in determining patient outcomes. Injuries to the head, neck, and spine are particularly serious and can result in life-threatening complications.

Impact of menopause-associated frailty on traumatic brain injury

Navigating menopause involves traversing a complex terrain of hormonal changes that extend far beyond reproductive consequences. Menopausal transition is characterized by a decrease in estradiol-17β (E2), and the impact of menopause resonates not only in the reproductive system but also through the central nervous system, musculoskeletal, and gastrointestinal domains. As women undergo menopausal transition, they become more susceptible to frailty, amplifying the risk and severity of injuries, including traumatic brain injury (TBI). Menopause triggers a cascade of changes leading to a decline in muscle mass, accompanied by diminished tone and excitability, thereby restricting the availability of irisin, a crucial hormone derived from muscles. Concurrently, bone mass undergoes reduction, culminating in the onset of osteoporosis and altering the dynamics of osteocalcin, a hormone originating from bones. The diminishing levels of E2 during menopause extend their influence on the gut microbiota, resulting in a reduction in the availability of tyrosine, tryptophan, and serotonin metabolites, affecting neurotransmitter synthesis and function. Understanding the interplay between menopause, frailty, E2 decline, and the intricate metabolisms of bone, gut, and muscle is imperative when unraveling the nuances of TBI after menopause. The current review underscores the significance of accounting for menopause-associated frailty in the incidence and consequences of TBI. The review also explores potential mechanisms to enhance gut, bone, and muscle health in menopausal women, aiming to mitigate frailty and improve TBI outcomes.

Endotoxemia Correlates with Kidney Function and Length of Stay in Critically Ill Patients

INTRODUCTION

Endotoxin is a key driver of sepsis, which frequently causes acute kidney injury (AKI). However, endotoxins may also be found in non-bacteremic critically ill patients, likely from intestinal translocation. Preclinical models show that endotoxins can directly injure the kidneys, and in COVID-19 patients, endotoxemia correlated with AKI. We sought to determine correlations between endotoxemia and kidney and hospital outcomes in a broad group of critically ill patients.

METHODS

In this single-center, serial prospective study, 124 predominantly Caucasian adult patients were recruited within 48 h of admission to Stony Brook University Hospital Intensive Care Unit (ICU). Demographics, vital signs, laboratory data, and outcomes were collected. Circulating endotoxin was measured on days 1, 4, and 8 using the endotoxin activity assay (EAA). The association of EAA with outcomes was examined with EAA: (1) categorized as <0.6, ≥0.6, and nonresponders (NRs); and (2) used as a continuous variable.

RESULTS

Patients with EAA ≥0.6 had a higher prevalence of proteinuria, and lower arterial oxygen saturation (SaO2) to fraction of inspired oxygen (FiO2) (SaO2/FiO2) ratio versus patients with EAA <0.6. EAA levels positively correlated with serum creatinine (sCr) levels on day 1. Patients whose EAA level stayed ≥0.6 had a slower decline in sCr compared to those whose EAA started at ≥0.6 and subsequently declined. Patients with AKI stage 1 and EAA ≥0.6 on day 1 showed slower decline in sCr compared to patients with stage 1 AKI and EAA <0.6. EAA ≥0.6 and NR patients had longer hospital stay and delayed ICU discharge versus EAA <0.6.

CONCLUSIONS

High EAA levels correlated with worse kidney function and outcomes. Patients whose EAA levels fell, and those with AKI stage I and day 1 EAA <0.6 recovered more quickly compared to those with EAA ≥0.6, suggesting that removal of circulating endotoxins may be beneficial in critically ill patients.

Gaps and opportunities in sepsis translational research

Infection initiates sepsis, but the clinical disease arises through the innate immune response of the host. A rapidly evolving understanding of the biology of that response has not been paralleled by the development of successful new treatment. The COVID-19 pandemic has begun to change this revealing the promise of distinct therapeutic approaches and the feasibility of new approaches to evaluate them. We review the history of mediator-targeted therapy for sepsis and explore the conceptual, biological, technological, and organizational challenges that must be addressed to enable the development of effective treatments for a leading cause of global morbidity and mortality.

Endotoxin removal therapy with Polymyxin B immobilized fiber column as a COVID-19-bedside strategy protocol for endotoxic shock

Endotoxin -induced sepsis is a leading cause of ICU mortality. From 1994 to the present, PMX-HP has been available as an adjuvant therapy for endotoxin removal and immunomodulation. The efficacy and usefulness of this therapy have been demonstrated for more than a quarter of a century and are partially supported by clinical studies. However, it appears that selected subgroups of patients with endotoxic shock and with appropriate timing could benefit. Endotoxemia may be involved in the pathophysiology of COVID-19, based on enterocyte dysfunction and malabsorptive syndrome. Due to the characteristics of the microbiota, Gram-negative bacteria or their fragments (i.e., endotoxin) may translocate into the systemic circulation leading to inflammatory activation, immune dysfunction, and sepsis. In addition, patients with severe forms of COVID-19 are at risk of superimposed infections. Endotoxemia can arise due to the translocation of Gram-negative bacteria or their fragments from the gut barrier. According to the most updated evidence available from large randomized trials, septic shock patients with MODS > 9 and EA levels ranging from 0.6 to 0.9 are those who may benefit the most from PMX-HP treatment in terms of improvement of survival. As shown in a previous publication, we believe that similarly to the source control, microbiological cultures, and antibiotics administration, EA evaluation at regular intervals, and the targeted use of PMX-HP could be lifesaving and adequate within the golden hour for the diagnosis and treatment of endotoxic shock. In our center, we applied a diagnostic-clinical flowchart also for endotoxic shock related to COVID-19.

Pathophysiology in patients with polytrauma

The pathophysiology after polytrauma represents a complex network of interactions. While it was thought for a long time that the direct and indirect effects of hypoperfusion are most relevant due to the endothelial permeability changes, it was discovered that the innate immune response to trauma is equally important in modifying the organ response. Recent multi center studies provided a "genetic storm" theory, according to which certain neutrophil changes are activated at the time of injury. However, a second hit phenomenon can be induced by activation of certain molecules by direct organ injury, or pathogens (damage associated molecular patterns, DAMPS - pathogen associated molecular patterns, PAMPS). The interactions between the four pathogenetic cycles (of shock, coagulopathy, temperature loss and soft tissue injuries) and cross-talk between coagulation and inflammation have also been identified as important modifiers of the clinical status. In a similar fashion, overzealous surgeries and their associated soft tissue injury and blood loss can induce secondary worsening of the patient condition. Therefore, staged surgeries in certain indications represent an important alternative, to allow for performing a "safe definitive surgery" strategy for major fractures. The current review summarizes all these situations in a detailed fashion.

Endotoxemia in Critically Ill Patients with COVID-19

Introduction

Mechanism(s) mediating critical illness in coronavirus disease 2019 (COVID-19) remain unclear. Previous reports demonstrate the existence of endotoxemia in viral infections without superimposed gram-negative bacteremia, but the rate and severity of endotoxemia in critically ill patients with COVID-19 requires further exploration.

Materials and Methods

This is a single-center cross-sectional study of 92 intensive care unit patients diagnosed with COVID-19 pneumonia. Endotoxin activity (EA) was measured in patients that met the following criteria: (1) age ≥18 years and (2) multi-organ dysfunction score >9 from March 24, 2020, to June 20, 2020.

Results

A total of 32 patients met the inclusion/exclusion criteria for measurement of EA. The median age of the study cohort was 60 years with a majority male (21/32, 65%) with hypertension (50%). A significant proportion of the patients exhibited either elevated EA in the intermediate range (0.40–0.59 EA units) (10/32, 31%) or high range (≥0.60 EA units) (14/32, 44%) or were nonresponders (NRs, low neutrophil response) to EA (6/32, 19%), with the presence of gram-negative bacteremia only in 2/32 (6%) patients. Low EA was reported in 2/32 patients. NRs (5/6, 83%) and patients with high EA (7/14, 50%) exhibited higher acute kidney injury (AKI) as compared to patients with low/intermediate EA level (1/12, 8.3%).

Discussion/Conclusion

Elevated EA was observed in a large majority of critically ill patients with COVID-19 and multi-organ dysfunction despite a low incidence of concurrent gram-negative bacteremia. While we observed that elevated EA and nonresponsiveness to EA were associated with AKI in critically ill patients with COVID-19, these findings require further validation in larger longitudinal cohorts.

Impact of uric acid on liver injury and intestinal permeability following resuscitated hemorrhagic shock in rats

BACKGROUND

Multiorgan failure is a consequence of severe ischemia-reperfusion injury after traumatic hemorrhagic shock (HS), a major cause of mortality in trauma patients. Circulating uric acid (UA), released from cell lysis, is known to activate proinflammatory and proapoptotic pathways and has been associated with poor clinical outcomes among critically ill patients. Our group has recently shown a mediator role for UA in kidney and lung injury, but its role in liver and enteric damage after HS remains undefined. Therefore, the objective of this study was to evaluate the role of UA on liver and enteric injury after resuscitated HS.

METHODS

A murine model of resuscitated HS was treated during resuscitation with a recombinant uricase, a urate oxidase enzyme (rasburicase; Sanofi-Aventis, Canada Inc, Laval, Canada), to metabolize and reduce circulating UA. Biochemical analyses (liver enzymes, liver apoptotic, and inflammatory markers) were performed at 24 hours and 72 hours after HS. Physiological testing for enteric permeability and gut bacterial product translocation measurement (plasma endotoxin) were performed 72 hours after HS. In vitro, HT-29 cells were exposed to UA, and the expression of intercellular adhesion proteins (ZO-1, E-cadherin) was measured to evaluate the influence of UA on enteric permeability.

RESULTS

The addition of uricase to resuscitation significantly reduced circulating and liver UA levels after HS. It also prevented HS-induced hepatolysis and liver apoptotic/inflammatory mediators at 24 hours and 72 hours. Hemorrhagic shock-induced enteric hyperpermeability and endotoxemia were prevented with uricase.

CONCLUSIONS

After resuscitated HS, UA is an important mediator in liver and enteric injury. Uric acid represents a therapeutic target to minimize organ damage in polytrauma patients sustaining HS.

Prominent Indomethacin-Induced Enteropathy in Fcgriib Defi-cient lupus Mice: An Impact of Macrophage Responses and Immune Deposition in Gut

A high dose of NSAIDs, a common analgesic, might induce lupus activity through several NSAIDs adverse effects including gastrointestinal permeability defect (gut leakage) and endotoxemia. Indomethacin (25 mg/day) was orally administered for 7 days in 24-wk-old Fc gamma receptor IIb deficient (FcgRIIb-/-) mice, an asymptomatic lupus model (increased anti-dsDNA without lupus nephritis), and age-matched wild-type (WT) mice. Severity of indomethacin-induced enteropathy in FcgRIIb-/- mice was higher than WT mice as demonstrated by survival analysis, intestinal injury (histology, immune-deposition, and intestinal cytokines), gut leakage (FITC-dextran assay and endotoxemia), serum cytokines, and lupus characteristics (anti-dsDNA, renal injury, and proteinuria). Prominent responses of FcgRIIb-/- macrophages toward lipopolysaccharide (LPS) compared to WT cells due to the expression of only activating-FcgRs without inhibitory-FcgRIIb were demonstrated. Extracellular flux analysis indicated the greater mitochondria activity (increased respiratory capacity and respiratory reserve) in FcgRIIb-/- macrophages with a concordant decrease in glycolysis activity when compared to WT cells. In conclusion, gut leakage-induced endotoxemia is more severe in indomethacin-administered FcgRIIb-/- mice than WT, possibly due to the enhanced indomethacin toxicity from lupus-induced intestinal immune-deposition. Due to a lack of inhibitory-FcgRIIb expression, mitochondrial function, and cytokine production of FcgRIIb-/- macrophages were more prominent than WT cells. Hence, lupus disease-activation from NSAIDs-enteropathy-induced gut leakage is possible.

Risk Factors of Bacteremia following Multiple Traumas

Background

Bacteremia is a major nosocomial infection that frequently occurs in trauma patients, increasing morbidity and mortality. The aim of this study was to identify risk factors and to describe epidemiological patterns for early onset (EOB) and late onset (LOB) bacteremia after trauma.

Methods

We retrospectively reviewed medical records of all trauma patients admitted to the surgical intensive care unit and general ward between January 2011 and December 2015. The information was collected for each patient and recorded in a computer database: early onset bacteremia (EOB) was defined as when onset occurred within 7 days after trauma, and late onset bacteremia (LOB) was defined as when onset occurred after 7 days from trauma.

Results

Thirty-four patients of 859 (4%) developed bacteremia during their hospital stay: 4 (11.8%) developed EOB, 26 (76.4%) LOB, and 4 (11.8%) patients developed both of them. Sixty events of bacteremia happened to these patients: 9 (15.0%) EOB and 51 (85.0%) LOB. Gram-positive cocci were isolated more frequently than Gram-negative bacilli in both groups. Gram-positive cocci were more frequently isolated in EOB than in LOB; otherwise, there was no statistical significance (77.8% vs. 64.7%, p=0.683). Central line-associated blood stream infection (CLABSI) and surgical site infection (SSI) were the most common identified source for LOB. Presence of liver (OR: 2.66, p=0.035) and pelvic injury (OR: 2.25, p=0.038), gastrointestinal tract perforation (OR: 5.48, p=0.002), and massive transfusion (OR: 3.36, p=0.006) represented risk factors for bacteremia.

Conclusions

Presence of pelvic and liver injury on arrival in emergency department, gastrointestinal tract perforation, and massive transfusion within the first 24 hours after trauma appears to be significant risk factors for bacteremia.

Endothelial heterogeneity across distinct vascular beds during homeostasis and inflammation

Blood vessels are lined by endothelial cells engaged in distinct organ-specific functions but little is known about their characteristic gene expression profiles. RNA-Sequencing of the brain, lung, and heart endothelial translatome identified specific pathways, transporters and cell-surface markers expressed in the endothelium of each organ, which can be visualized at http://www.rehmanlab.org/ribo. We found that endothelial cells express genes typically found in the surrounding tissues such as synaptic vesicle genes in the brain endothelium and cardiac contractile genes in the heart endothelium. Complementary analysis of endothelial single cell RNA-Seq data identified the molecular signatures shared across the endothelial translatome and single cell transcriptomes. The tissue-specific heterogeneity of the endothelium is maintained during systemic in vivo inflammatory injury as evidenced by the distinct responses to inflammatory stimulation. Our study defines endothelial heterogeneity and plasticity and provides a molecular framework to understand organ-specific vascular disease mechanisms and therapeutic targeting of individual vascular beds.

Blood vessels supply nutrients, oxygen and other key molecules to all of the organs in the body. Cells lining the blood vessels, called endothelial cells, regulate which molecules pass from the blood to the organs they supply. For example, brain endothelial cells prevent toxic molecules from getting into the brain, and lung endothelial cells allow immune cells into the lungs to fight off bacteria or viruses.

Determining which genes are switched on in the endothelial cells of major organs might allow scientists to determine what endothelial cells do in the brain, heart, and lung, and how they differ; or help scientists deliver drugs to a particular organ. If endothelial cells from different organs switch on different groups of genes, each of these groups of genes can be thought of as a ‘genetic signature’ that identifies endothelial cells from a specific organ.

Now, Jambusaria et al. show that brain, heart, and lung endothelial cells have distinct genetic signatures. The experiments used mice that had been genetically modified to have tags on their endothelial cells. These tags made it possible to isolate RNA – a molecule similar to DNA that contains the information about which genes are active – from endothelial cells without separating the cells from their tissue of origin. Next, RNA from endothelial cells in the heart, brain and lung was sequenced and analyzed.

The results show that each endothelial cell type has a distinct genetic signature under normal conditions and infection-like conditions. Unexpectedly, the experiments also showed that genes that were thought to only be switched on in the cells of specific tissues are also on in the endothelial cells lining the blood vessels of the tissue. For example, genes switched on in brain cells are also active in brain endothelial cells, and genes allowing heart muscle cells to pump are also on in the endothelial cells of the heart blood vessels.

The endothelial cell genetic signatures identified by Jambusaria et al. can be used as “postal codes” to target drugs to a specific organ via the endothelial cells that feed it. It might also be possible to use these genetic signatures to build organ-specific blood vessels from stem cells in the laboratory. Future work will try to answer why endothelial cells serving the heart and brain use genes from these organs.

Reduced Proprotein convertase subtilisin/kexin 9 (PCSK9) function increases lipoteichoic acid clearance and improves outcomes in Gram positive septic shock patients

Previous studies have shown lipopolysaccharide from Gram-negative bacteria is cleared from the circulation via LDL receptors on hepatocytes, which are downregulated by PCSK9. Whether clearance of Gram positive bacterial lipoteichoic acid (LTA) shows similar dependence on PCSK9, and whether this is clinically relevant in Gram positive human sepsis, is unknown. We examined survival data from three cohorts of patients who had Gram positive septic shock (n = 170, n = 130, and n = 59) and found that patients who carried a PCSK9 loss-of-function (LOF) allele had significantly higher 28-day survival (73.8%) than those with no LOF alleles (52.8%) (p = 0.000038). Plasma clearance of LTA was also found to be increased in PCSK9 knockout mice compared to wildtype control mice (p = 0.002). In addition, hepatocytes pre-treated with recombinant wildtype PCSK9 showed a dose-dependent decrease in uptake of fluorescently-labeled LTA (p < 0.01). In comparison to wildtype PCSK9, hepatocytes pre-treated with 3 different LOF variants of recombinant PCSK9 showed an increase in LTA uptake. This study shows the clearance of LTA follows a similar route as lipopolysaccharide, which is dependent on hepatic LDL receptors. This has important implications in health as strategies aimed at inhibiting PCSK9 function may be an effective treatment option for both Gram-positive and negative sepsis.

Children With Noncritical Infections Have Increased Intestinal Permeability, Endotoxemia and Altered Innate Immune Responses

BACKGROUND

Children with critical illness have increased intestinal permeability and a period of immunoparalysis, mediated by elevated circulating endotoxin. Whether children with less severe infections have similar changes is uncertain.

METHODS

We conducted a proof-of-concept pilot study, enrolling children 6-59 months of age hospitalized for noncritical infections (cases, n = 11) and noninfected controls (n = 19). Intestinal permeability was measured by lactulose-mannitol recovery. Plasma endotoxin, blood monocyte and neutrophil immunophenotypes and cytokine elaboration following 24-hour whole-blood culture with antigens targeting distinct innate pathogen recognition receptor signaling pathways were evaluated.

RESULTS

Cases had higher intestinal permeability and plasma endotoxin levels than controls. Among cases versus controls, fewer monocytes expressed human leukocyte antigen DR isotype (HLA-DR) (87.1% vs. 96.4%, P = 0.001), and more expressed CD64 (99.6% vs. 97.6%, P = 0.041). Following zymosan stimulation of whole blood, cases versus controls produced less interleukin 1 beta (IL-1β) (median 1101 vs. 2604 pg/mL, P = 0.048) and tumor necrosis factor alpha (TNF-α) (2342 vs. 5130 pg/mL, P = 0.031). Children with higher (≥0.1 endotoxin unit (EU)/mL) versus lower (<0.1 EU/mL) circulating endotoxin had fewer monocytes expressing CD86 (69.8% vs. 92.4%, P = 0.003) and less expression of CD64 following 24-hour zymosan stimulation (median fluorescence intensity (MFI) 1514 vs. 2196, P = 0.022).

CONCLUSIONS

Children hospitalized with noncritical infections had increased intestinal permeability, endotoxemia and altered monocyte phenotype and function. Collectively, these changes are typical of immunoparalysis seen in children with critical illness and may increase the risk of subsequent infections.

Association between endotoxemia and enterocyte injury and clinical course in patients with gram-positive septic shock: A posthoc analysis of a prospective observational study

Endotoxemia often occurs in patients with gram-positive infections. The possible mechanism is thought to be bacterial translocation after enterocyte hypoperfusion injury. However, the association between endotoxemia and enterocyte injury among patients with gram-positive septic shock has never been assessed. The aim of this study was to evaluate the association between endotoxemia and enterocyte injury in gram-positive septic shock patients and to evaluate the association among endotoxemia, subsequent clinical course, and other related factors.This was a posthoc analysis of a prospective observational study that evaluated the capability of intestinal fatty acid-binding protein (I-FABP), an indicator of enterocyte injury, to predict mortality. Among 57 patients in septic shock, those whose causative microorganisms were gram positive were included. The correlation between endotoxin activity (EA), which indicates endotoxemia, and I-FABP levels upon admission to the intensive care unit (ICU), the clinical course, and other related factors were evaluated.A total of 21 patients were examined. One-third of the patients presented with high EA levels at the time of ICU admission. However, there was no significant correlation between EA and I-FABP levels (Spearman ρ = 0.002, P = .993). Additionally, high EA levels were not associated with abdominal complications after ICU admission or mortality. Similarly, high EA levels were not associated with severity scores, inotropic scores, or lactate levels upon ICU admission, which were previously reported to be factors related to high EA levels.In this posthoc analysis, no correlation was observed between endotoxemia and enterocyte injury among patients in gram-positive septic shock. Additionally, high EA levels were not associated with the clinical course and reported factors related to endotoxemia. Although our results need to be validated in a large prospective cohort study, hypoperfusion enterocyte injury might not be a cause of endotoxemia in these patients. Thus, if there is no correlation between EA and I-FABP levels, other mechanisms that induce high EA levels among patients with gram-positive septic shock should be elucidated.

Comparative Evaluation of Endotoxin Activity Level and Various Biomarkers for Infection and Outcome of ICU-Admitted Patients

Here, we concurrently measured the endotoxin activity (EA) level and levels of multiple biomarkers in patient blood obtained within 24 h after being admitted into the intensive care unit (ICU) and analyzed whether there were links between these markers and their associations with patient conditions and outcomes. The EA levels highly correlated with disease severity and patient survival, and showed a significant positive association with levels of lactate, procalcitonin, presepsin, and interleukin-6. Notably, the EA level was the marker that most highly correlated with the results of blood culture, and the presepsin level was the marker most highly correlated with the survival outcome at 28 days. Thus, the optimal biomarker should be selected based on whether it will be used to discriminate the presence of an infection or to predict survival.

Comparison of the source and prognostic utility of cfDNA in trauma and sepsis

BACKGROUND

Circulating cell-free DNA (cfDNA) may contribute to the pathophysiology of post-injury inflammation and coagulation in trauma. However, the source and mechanism of release of cfDNA in trauma is not well understood. One potential source of cfDNA is from Neutrophil Extracellular Traps (NETs), released by activated neutrophils during the process of NETosis. The primary objective of our study was to determine if cfDNA has prognostic utility in trauma. The secondary objective of this study was to determine the source of cfDNA in trauma compared to sepsis.

METHODS

We studied trauma patients from two prospective observational cohort studies: the DNA as a Prognostic Marker in ICU Patients (DYNAMICS) study and the Endotoxin in Polytrauma (ENPOLY) study. We also studied septic patients from the DYNAMICS study. Citrated plasma samples were collected longitudinally from the patients (days 1 to 7). The following molecules were measured in the plasma samples: cfDNA, protein C (PC), myeloperoxidase (MPO) (a marker of neutrophil activation), citrullinated Histone H3 (H3Cit, a marker of NETosis), cyclophilin A (a marker of necrosis), and caspase-cleaved K18 (a marker of apoptosis).

RESULTS

A total of 77 trauma patients were included (n = 38 from DYNAMICS and n = 39 from ENPOLY). The median age was 49 years; 27.3% were female, and mortality was 16.9% at 28 days. Levels of cfDNA were elevated compared to healthy values but not significantly different between survivors and non-survivors. There was a positive correlation between MPO and cfDNA in septic patients (r = 0.424, p < 0.001). In contrast, there was no correlation between MPO and cfDNA in trauma patients (r = - 0.192, p = 0.115). Levels of H3Cit, a marker of NETosis, were significantly elevated in septic patients compared to trauma patients (p < 0.01) while apoptosis and necrosis markers did not differ between the two groups.

CONCLUSION

Our studies suggest that the source and mechanism of release of cfDNA differ between trauma and sepsis patients. In sepsis, cfDNA is likely primarily released by activated neutrophils via the process of NETosis. In contrast, cfDNA in trauma appears to originate mainly from injured or necrotic cells. Although cfDNA is elevated in trauma and sepsis patients compared to healthy controls, cfDNA does not appear to have prognostic utility in trauma patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01355042 . Registered May 17, 2011.

A pilot study into the use of Continuous Venous Hyperfiltration to manage patients in a critical state with dysregulated inflammation

INTRODUCTION

Haemofiltration paradigms used to manage critically ill patients with a dysregulated inflammatory response (DIR) assess kidney function to monitor its onset, adaptation, and completion. A Continuous Venous Hyperfiltration (CONVEHY) protocol is presented, in which a non-specific adsorption membrane (AN69-ST-Heparin Grafted) is used with citrate as an anticoagulant and substitution fluid. CONVEHY uses tools readily available to achieve kidney related and non-related objectives, and it is guided by the monitoring of pathophysiological responses.

OBJECTIVES

To compare the response to an AN69-ST-HG membrane when heparin (He, n=5: Standard protocol) or citrate (Ci, n=6: CONVEHY protocol) was used to evaluate whether a larger study into the benefits of this protocol would be feasible.

MATERIALS AND METHODS

In a retrospective pilot study, the benefits of the CONVEHY protocol to manage patients with a DIR in a surgical critical care unit (CCUs) were assessed by evaluating the SOFA (Sequential Organ Failure Assessment) (He 11 ± 2.35; Ci 11 ± 3.63: p=0.54) and APACHE II (He 28.60 ± 9.40; Ci 24 ± 8.46: p=0.93) scores.

RESULTS

Nights in hospital (He 35.2 ± 16.3 nights; Ci 9 ± 2.53: p=0.004), hospital admission after discharge from the CCUs (He 40.25 ± 21.82; Ci 13.2 ± 4.09: p=0.063), patients hospitalised >20 days (He 80%; Ci 0%: p=0.048), days requiring mechanical ventilation (He 16 ± 5.66; Ci 4 ± 1.72: p=0.004), and the predicted (55.39 ± 26.13%) versus real mortality in both groups (9.1%: p=0.004).

CONCLUSIONS

The CONVEHY protocol improves the clinical responses of patients with DIR, highlighting the potential value of performing larger and confirmatory studies.

Trauma-Induced Long-Term Alterations of Human T Cells and Monocytes-Results of an Explorative, Cross-Sectional Study

BACKGROUND

Major trauma leads to complex immune reactions, known to result in a transient immunodeficiency. The long-term consequences of severe trauma on immune function and regulation as well as its clinical impact remain unclear.

METHODS

Six months (ranging from -12 to +5 days) after a major trauma event, 12 former trauma patients (Injury Severity Score ≥ 16) and 12 healthy volunteers were enrolled. The current clinical status and infection history since discharge were assessed by a standardized questionnaire. Immune cell subsets (cluster of differentiation (CD)4, CD8, CD14), cell surface receptor expression (programmed cell death protein 1 (PD-1), B- and T-lymphocyte attenuator (BTLA), cytotoxic T-lymphocyte-associated protein 4, toll-like receptor (TLR)-2, -4, and -5, Dectin-1, programmed death ligand 1 (PD-1L)), and human leucocyte antigen D-related receptor (HLA-DR)-expression were quantified by flow cytometry. Cytokine secretion (IL-2, -4, -6, -10, and 17A, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ) was assessed after stimulation of whole blood with LPS-, α-CD3/28, or zymosan.

RESULTS

Analysis of surface receptors on T cells revealed a significant elevation of PD-1 expression on CD4 T cells, whereas BTLA expression on CD4 and CD8 T cells was significantly suppressed in the trauma cohort. Monocytes showed a significantly reduced expression of TLR-2 and -4 as well as a reduced proportion of TLR-4 monocytes. HLA-DR receptor density revealed no significant changes between both cohorts. LPS-induced IL-6 and TNF-α secretion showed non-significant trends toward reduced values. No differences regarding clinical apparent infections could be detected.

CONCLUSIONS

Six months following major trauma, changes of cell surface receptors on CD4 and CD8 T cells as well as on CD14 monocytes were present, hinting toward an immunosuppressive phenotype. Following major trauma, although IL-6 and TNF-α release after stimulation were reduced, they did not reach statistical significance. Overall, further studies are necessary to evaluate the clinical implications of these findings.

TRIAL REGISTRATION

DRKS00009876, Internet Portal of the German Clinical Trials Register (DRKS), registration date 11.08.2016, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00009876.

Innate immune responses to trauma

Trauma can affect any individual at any location and at any time over a lifespan. The disruption of macrobarriers and microbarriers induces instant activation of innate immunity. The subsequent complex response, designed to limit further damage and induce healing, also represents a major driver of complications and fatal outcome after injury. This Review aims to provide basic concepts about the posttraumatic response and is focused on the interactive events of innate immunity at frequent sites of injury: the endothelium at large, and sites within the lungs, inside and outside the brain and at the gut barrier.

S100A8/A9 and sRAGE kinetic after polytrauma; an explorative observational study

Background

Following tissue injury after trauma, the activation of innate immune pathways results in systemic inflammation, organ failure and an increased risk of infections. The objective of this study was to characterize the kinetics of the S100A8/S100A9 complex, a new-recognized alarmin, as well as its soluble receptor sRAGE, over time after trauma as potential early biomarkers of the risk of organ damage.

Methods

We collected comprehensive data from consenting patients admitted to an ICU following severe trauma. The blood samples were taken at Day 0 (admission), Day1, 3 and 5 S100A8/A9 and sRAGE were measured by ELISA. Biomarkers levels were reported as median (IQR).

Results

Thirty-eight patients sustaining in majority a blunt trauma (89%) with a median ISS of 39 were included. In this cohort, the S100A8/A9 complex increased significantly over time (p = 0.001), but its levels increment over time (D0 to D5) was significantly smaller in patients developing infection (7.6 vs 40.1 mcg/mL, p = 0.011). The circulating level of sRAGE circulating levels decreased over time (p < 0.0001) and was higher in patients who remained in shock on day 3 (550 vs 918 pg/mL; p = 0.02) or 5 (498 vs 644 pg/mL; p = 0.045). Admission sRAGE levels were significantly higher in non-survivors (1694 vs 745 pg/mL; p = 0.015) and was higher in patients developing renal failure (1143 vs 696 pg/mL, p = 0.011).

Discussion

Our findings reveal an interesting association between the biomarker S100A8/9 least increase over time and the presence of infectious complication after trauma. We describe that the sRAGE decline over time is in relation with shock and markers of ischemic injury. We also confirm the association of sRAGE levels measured at admission with mortality and the development of renal failure.

Conclusions

This work illustrates the importance of following the circulating level of biomarker overtime. The utilization of S1008/9 as a tool to stratify infection risk and trigger early interventions need to be validated prospectively.

Polytrauma Defined by the New Berlin Definition: A Validation Test Based on Propensity-Score Matching Approach

Background: Polytrauma patients are expected to have a higher risk of mortality than that obtained by the summation of expected mortality owing to their individual injuries. This study was designed to investigate the outcome of patients with polytrauma, which was defined using the new Berlin definition, as cases with an Abbreviated Injury Scale (AIS) ≥ 3 for two or more different body regions and one or more additional variables from five physiologic parameters (hypotension [systolic blood pressure ≤ 90 mmHg], unconsciousness [Glasgow Coma Scale score ≤ 8], acidosis [base excess ≤ -6.0], coagulopathy [partial thromboplastin time ≥ 40 s or international normalized ratio ≥ 1.4], and age [≥70 years]). Methods: We retrieved detailed data on 369 polytrauma patients and 1260 non-polytrauma patients with an overall Injury Severity Score (ISS) ≥ 18 who were hospitalized between 1 January 2009 and 31 December 2015 for the treatment of all traumatic injuries, from the Trauma Registry System at a level I trauma center. Patients with burn injury or incomplete registered data were excluded. Categorical data were compared with two-sided Fisher exact or Pearson chi-square tests. The unpaired Student t-test and the Mann-Whitney U-test was used to analyze normally distributed continuous data and non-normally distributed data, respectively. Propensity-score matched cohort in a 1:1 ratio was allocated using the NCSS software with logistic regression to evaluate the effect of polytrauma on patient outcomes. Results: The polytrauma patients had a significantly higher ISS than non-polytrauma patients (median (interquartile range Q1-Q3), 29 (22-36) vs. 24 (20-25), respectively; p < 0.001). Polytrauma patients had a 1.9-fold higher odds of mortality than non-polytrauma patients (95% CI 1.38-2.49; p < 0.001). Compared to non-polytrauma patients, polytrauma patients had a substantially longer hospital length of stay (LOS). In addition, a higher proportion of polytrauma patients were admitted to the intensive care unit (ICU), spent longer LOS in the ICU, and had significantly higher total medical expenses. Among 201 selected propensity score-matched pairs of polytrauma and non-polytrauma patients who showed no significant difference in sex, age, co-morbidity, AIS ≥ 3, and Injury Severity Score (ISS), the polytrauma patients had a significantly higher mortality rate (OR 17.5, 95% CI 4.21-72.76; p < 0.001), and a higher proportion of patients admitted to the ICU (84.1% vs. 74.1%, respectively; p = 0.013) with longer stays in the ICU (10.3 days vs. 7.5 days, respectively; p = 0.003). The total medical expenses for polytrauma patients were 35.1% higher than those of non-polytrauma patients. However, there was no significant difference in the LOS between polytrauma and non-polytrauma patients (21.1 days vs. 19.8 days, respectively; p = 0.399). Conclusions: The findings of this propensity-score matching study suggest that the new Berlin definition of polytrauma is feasible and applicable for trauma patients.

Endotoxin adsorption: Direct hemoperfusion with the polymyxin B-immobilized fiber column (PMX)

Toraymyxin^® is a medical device developed to adsorb circulating endotoxins in the blood using direct hemoperfusion therapy for patients with septic shock. In 1994, the Japanese National Health Insurance system approved the use of Toraymyxin for the treatment of endotoxemia and septic shock. Since then, Toraymyxin has been safely used in more than 100,000 cases in emergency and intensive care units in Japan. Toraymyxin is currently available for use in the clinical setting in 14 countries worldwide. In this study, we reviewed and introduced the development, clinical use, and efficacy of Toraymyxin and commented on its anticoagulant use and cartridge clotting issue in the treatment of severe sepsis and septic shock. We also highlighted potential new applications of Toraymyxin for longer duration therapy and pulmonary diseases.

Klotho suppresses the inflammatory responses and ameliorates cardiac dysfunction in aging endotoxemic mice

Background

Aging augments endotoxemic cardiac dysfunction, but the mechanism remains unclear. Anti-aging protein Klotho has been found to modulate tissue inflammatory responses. We tested the hypothesis that a reduced Klotho level in aging heart plays a role in the augmented endotoxemic cardiac dysfunction.

Materials and Methods

Endotoxin (0.5 mg/kg, iv) was injected to adults (4-6 months) and aging (18-20 months) C57BL/6 mice. Recombinant Klotho (10 μg/kg, iv) was administered to a group of aging mice after endotoxin injection. Cardiac function was analyzed using a microcatheter at 24 and 48 h after endotoxin administration. Myocardial levels of Klotho and heat shock protein 70 (HSP70) were determined by immunoblotting, and plasma and myocardial cytokines were analyzed using ELISA.

Results

More severe cardiac dysfunction in aging mice were accompanied by greater cytokine levels in the plasma and myocardium. Klotho was detected in the myocardial tissue. Klotho levels were lower in aging hearts and were further reduced during endotoxemia. Myocardial HSP70 levels were correlated with Klotho levels. Recombinant Klotho increased myocardial HSP70, inhibited NF-κB activation, reduced cytokine levels, and improved cardiac function in aging endotoxemic mice. Delivery of HSP70 into cultured macrophages suppressed endotoxin-induced NF-κB activation.

Conclusions

Aging-related augmentation of inflammatory responses and cardiac dysfunction is associated with relative Klotho deficiency. Post-treatment with recombinant Klotho suppresses the inflammatory responses and improves cardiac function in aging endotoxemic mice. Klotho modulates HSP70 levels and HSP70 appears to be involved in the anti-inflammatory mechanism of Klotho. Klotho may have therapeutic potential in amelioration of aging-related endotoxemic cardiac dysfunction.

Interleukin-37 suppresses the inflammatory response to protect cardiac function in old endotoxemic mice

Myocardial inflammatory responses to endotoxemia are enhanced in old mice, which results in worse cardiac dysfunction. Anti-inflammatory cytokine interleukin (IL)-37 has a broad effect on innate immunoresponses. We hypothesized that IL-37 suppresses myocardial inflammatory responses to protect cardiac function during endotoxemia in old mice. Old (20-24month) wild-type (WT), and IL-37 transgenic (IL-37tg) mice were treated with lipopolysaccharide (LPS, 0.5mg/kg, iv) or normal saline (0.1ml/mouse, iv). Six hours later, left ventricle (LV) function was assessed using a pressure-volume microcatheter. Levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in plasma and myocardial tissue, as well as mononuclear cell density in the myocardium, were examined. Cardiac microvascular endothelial cells isolated from WT and IL-37tg mice were treated with LPS (0.2µg/ml) for 0.5-24h. Nuclear factor-kappa B (NF-κB) p65 phosphorylation was examined by immunoblotting, and MCP-1 levels in cell culture supernatant was determined using enzyme-linked immunosorbent assay. LV dysfunction in old WT endotoxemic mice was accompanied by up-regulated MCP-1, myocardial accumulation of mononuclear cells and production of TNF-α, IL-1β and IL-6. Expression of IL-37 suppressed myocardial inflammatory responses to endotoxemia in old mice, resulting in improved LV function. Treatment of old WT endotoxemic mice with recombinant IL-37 also improved LV function. In vitro experiments revealed that cardiac microvascular endothelial cells from IL-37tg mice had attenuated NF-κB activation and MCP-1 production following LPS stimulation. In conclusion, IL-37 is potent to suppress myocardial inflammation and protects against cardiac dysfunction during endotoxemia in old mice.

Déjà-vu from the nineties: is there a perspective for anti-endotoxin strategies to improve the outcome of multiple trauma patients?

A recent cohort study of Charbonney et al. indicates that multiple trauma patients develop endotoxemia also in the absence of Gram-negative infection. This is most probably due to an increase of gut permeability. Non-survivors as well as patients with cardiovascular dysfunction and multiple organ failure (MOF) show significantly higher endotoxin levels at 24 h after injury compared to survivors and patients without MOF. These results are like a déjà-vu from the nineties of the last century, where several studies reported endotoxemia during the initial 24 h after multiple trauma with development of MOF and death at endotoxin levels >10 and >12 pg/mL, respectively. Of interest, other multiple trauma patient studies in the nineties have shown endogenous anti-endotoxin antibody production in survivors and reduced antibody production in non-survivors, which died from MOF. Although all these studies have pointed towards a mechanistic role of endotoxin in the fatal outcome after multiple injuries, clinical anti-endotoxin studies are still lacking. Thus, the future perspective must be prospective randomized multicenter trials, which have to elucidate the capability of anti-endotoxin treatment strategies to improve outcome in multiple trauma patients.

A Broad-Spectrum Infection Diagnostic that Detects Pathogen-Associated Molecular Patterns (PAMPs) in Whole Blood

Background

Blood cultures, and molecular diagnostic tests that directly detect pathogen DNA in blood, fail to detect bloodstream infections in most infected patients. Thus, there is a need for a rapid test that can diagnose the presence of infection to triage patients, guide therapy, and decrease the incidence of sepsis.

Methods

An Enzyme-Linked Lectin-Sorbent Assay (ELLecSA) that uses magnetic microbeads coated with an engineered version of the human opsonin, Mannose Binding Lectin, containing the Fc immunoglobulin domain linked to its carbohydrate recognition domain (FcMBL) was developed to quantify pathogen-associated molecular patterns (PAMPs) in whole blood. This assay was tested in rats and pigs to explore whether it can detect infections and monitor disease progression, and in prospectively enrolled, emergency room patients with suspected sepsis. These results were also compared with data obtained from non-infected patients with or without traumatic injuries.

Results

The FcMBL ELLecSA was able to detect PAMPS present on, or released by, 85% of clinical isolates representing 47 of 55 different pathogen species, including the most common causes of sepsis. The PAMP assay rapidly (< 1 h) detected the presence of active infection in animals, even when blood cultures were negative and bacteriocidal antibiotics were administered. In patients with suspected sepsis, the FcMBL ELLecSA detected infection in 55 of 67 patients with high sensitivity (> 81%), specificity (> 89%), and diagnostic accuracy of 0·87. It also distinguished infection from trauma-related inflammation in the same patient cohorts with a higher specificity than the clinical sepsis biomarker, C-reactive Protein.

Conclusion

The FcMBL ELLecSA-based PAMP assay offers a rapid, simple, sensitive and specific method for diagnosing infections, even when blood cultures are negative and antibiotic therapy has been initiated. It may help to triage patients with suspected systemic infections, and serve as a companion diagnostic to guide administration of emerging dialysis-like sepsis therapies.

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The FcMBL ELLecSA-based PAMP assay offers a rapid, simple, sensitive and specific method for diagnosing infections.

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The FcMBL ELLecSA distinguished infection from trauma-related inflammation.

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It can detect infection even when blood cultures are negative and antibiotic therapy has been initiated.

Current diagnostics of sepsis using blood cultures and molecular diagnostic tests fail to detect bloodstream infections in most infected patients, whereas the inflammatory biomarkers of infection that have a higher sensitivity of detection, lack specificity in distinguishing infection from trauma-related inflammation. Therefore we have leveraged a broad-spectrum pathogen binding opsonin and developed a rapid test to directly diagnose the presence of infection in the blood to triage patients and guide antibiotic therapy.