Pulmonary Events in ICU patients with hyperoxia: is it possible to relate arterial partial pressure of oxygen to coded diseases? A retrospective analysis

OBJECTIVE

Oxygen has been used liberally in ICUs for a long time to prevent hypoxia in ICU- patients. Current evidence suggests that paO2 >300 mmHg should be avoided, it remains uncertain whether an "optimal level" exists. We investigated how "mild" hyperoxia influences diseases and in-hospital mortality.

DESIGN

This is a retrospective study.

SETTING

112 mechanically ventilated ICU-patients were enrolled.

PATIENTS OR PARTICIPANTS

112 ventilated patients were included and categorized into two groups based on the median paO2 values measured in initial 24 h of mechanical ventilation: normoxia group (paO2 ≤ 100 mmHg, n = 43) and hyperoxia group patients (paO2 > 100 mmHg, n = 69).

INTERVENTIONS

No interventions were performed.

MAIN VARIABLES OF INTEREST

The primary outcome was the incidence of pulmonary events, the secondary outcomes included the incidence of other new organ dysfunctions and in-hospital mortality.

RESULTS

The baseline characteristics, such as age, body mass index, lactate levels, and severity of disease scores, were similar in both groups. There were no statistically significant differences in the incidence of pulmonary events, infections, and new organ dysfunctions between the groups. 27 out of 69 patients (39.1%) in the "mild" hyperoxia group and 12 out of 43 patients (27.9%) in the normoxia group died during their ICU or hospital stay (p = 0.54). The mean APACHE Score was 29.4 (SD 7.9) in the normoxia group and 30.0 (SD 6.7) in the hyperoxia group (p = 0.62).

CONCLUSIONS

We found no differences in pulmonary events, other coded diseases, and in-hospital mortality between both groups. It remains still unclear what the "best oxygen regime" is for intensive care patients.

miR-Blood - a small RNA atlas of human blood components

miR-Blood is a high-quality, small RNA expression atlas for the major components of human peripheral blood (plasma, erythrocytes, thrombocytes, monocytes, neutrophils, eosinophils, basophils, natural killer cells, CD4+ T cells, CD8+ T cells, and B cells). Based on the purified blood components from 52 individuals, the dataset provides a comprehensive repository for the expression of 4971 small RNAs from eight non-coding RNA classes.

Evaluation of the Novel Sepsis Biomarker Host-Derived Delta-like Canonical Notch Ligand 1-A Secondary Analysis of 405 Patients Suffering from Inflammatory or Infectious Diseases

Sepsis is defined as organ failure caused by dysregulated host response to infection. While early antibiotic treatment in patients with acute infection is essential, treating non-infectious patients must be avoided. Current guidelines recommend procalcitonin (PCT) to guide discontinuation of antibiotic treatment. For initiation of therapy, there is currently no recommended biomarker. In this study, we evaluated Host-Derived Delta-like Canonical Notch Ligand 1 (DLL1), a monocyte membrane ligand that has shown promising results in differentiating infectious from non-infectious critically ill patients. Soluble DLL1 levels were measured in plasma samples of six different cohorts. The six cohorts comprise two cohorts with non-infectious inflammatory auto-immune diseases (Hidradenitis Suppurativa, Inflammatory Bowel Disease), one cohort of bacterial skin infection, and three cohorts of suspected systemic infection or sepsis. In total, soluble DLL1 plasma levels of 405 patients were analyzed. Patients were divided into three groups: inflammatory disease, infection, and sepsis (defined according to the Sepsis-3 definition), followed by the evaluation of its diagnostic performance via Area Under the Receiver Operating Characteristics (AUROC) analyses. Patients of the sepsis group showed significantly elevated plasma DLL1 levels compared to patients with uncomplicated infections and sterile inflammation. However, patients with infections had significantly higher DLL1 levels than patients with inflammatory diseases. Diagnostic performance was evaluated and showed better performance for DLL1 for the recognition of sepsis (AUC: 0.823; CI 0.731-0.914) than C-reactive protein (AUC 0.758; CI 0.658-0.857), PCT (AUC 0.593; CI 0.474-0.711) and White Blood Cell count (AUC 0.577; CI 0.46-0.694). DLL1 demonstrated promising results for diagnosing sepsis and was able to differentiate sepsis from other infectious and inflammatory diseases.

suPAR links a dysregulated immune response to tissue inflammation and sepsis-induced acute kidney injury

Acute kidney injury (AKI) secondary to sepsis results in poor outcomes and conventional kidney function indicators lack diagnostic value. Soluble urokinase plasminogen activator receptor (suPAR) is an innate immune-derived molecule implicated in inflammatory organ damage. We characterized the diagnostic ability of longitudinal serum suPAR levels to discriminate severity and course of sepsis-induced AKI (SI-AKI) in 200 critically ill patients meeting Sepsis-3 criteria. The pathophysiologic relevance of varying suPAR levels in SI-AKI was explored in a polymicrobial sepsis model in WT, (s)uPAR-knockout, and transgenic suPAR-overexpressing mice. At all time points studied, suPAR provided a robust classification of SI-AKI disease severity, with improved prediction of renal replacement therapy (RRT) and mortality compared with established kidney biomarkers. Patients with suPAR levels of greater than 12.7 ng/mL were at highest risk for RRT or death, with an adjusted odds ratio of 7.48 (95% CI, 3.00-18.63). suPAR deficiency protected mice against SI-AKI. suPAR-overexpressing mice exhibited greater kidney damage and poorer survival through inflamed kidneys, accompanied by local upregulation of potent chemoattractants and pronounced kidney T cell infiltration. Hence, suPAR allows for an innate immune-derived and kidney function-independent staging of SI-AKI and offers improved longitudinal risk stratification. suPAR promotes T cell-based kidney inflammation, while suPAR deficiency improves SI-AKI.

Gαq modulates the energy metabolism of osteoclasts

Introduction

The bacterial protein toxin Pasteurella multocida toxin (PMT) mediates RANKL-independent osteoclast differentiation. Although these osteoclasts are smaller, their resorptive activity is high which helps in efficient destruction of nasal turbinate bones of pigs.

Methods

The proteome of bone marrow-derived macrophages differentiated into osteoclasts with either RANKL or PMT was analysed. The results were verified by characterizing the metabolic activity using Seahorse analysis, a protein translation assay, immunoblots, real-time PCR as well as flow cytometry-based monitoring of mitochondrial activity and ROS production. A Gαq overexpression system using ER-Hoxb8 cells was used to identify Gαq-mediated metabolic effects on osteoclast differentiation and function.

Results

PMT induces the upregulation of metabolic pathways, which included strong glycolytic activity, increased expression of GLUT1 and upregulation of the mTOR pathway. As OxPhos components were expressed more efficiently, cells also displayed increased mitochondrial respiration. The heterotrimeric G protein Gαq plays a central role in this hypermetabolic cell activation as it triggers mitochondrial relocalisation of pSerSTAT3 and an increase in OPA1 expression. This seems to be caused by a direct interaction between STAT3 and OPA1 resulting in enhanced mitochondrial respiration. Overexpression of Gαq mimicked the hypermetabolic phenotype observed for PMT-induced osteoclasts and resulted in higher glycolytic and mitochondrial activity as well as increased bone resorptive activity. In addition, rheumatoid arthritis (RA) patients showed an increase in GNAQ expression, especially in the synovial fluid.

Discussion

Our study suggests that Gαq plays a key role in PMT-induced osteoclastogenesis. Enhanced expression of GNAQ at the site of inflammation in RA patients indicates its pathophysiological relevance in the context of inflammatory bone disorders.

Interleukin-3 protects against viral pneumonia in sepsis by enhancing plasmacytoid dendritic cell recruitment into the lungs and T cell priming

Rationale

Sepsis, a global health burden, is often complicated by viral infections leading to increased long-term morbidity and mortality. Interleukin-3 (IL-3) has been identified as an important mediator amplifying acute inflammation in sepsis; however, its function in the host response to viral infections during sepsis remains elusive.

Objectives

To investigate the role of IL-3 during viral pneumonia in sepsis.

Methods

We included septic patients from two different cohorts and used in vitro and in vivo assays. The obtained data were substantiated using a second model (SARS-CoV-2 infections).

Measurements and main results

Low plasma IL-3 levels were associated with increased herpes simplex virus (HSV) airway infections in septic patients, resulting in reduced overall survival. Likewise, Il-3-deficient septic mice were more susceptible to pulmonary HSV-1 infection and exhibited higher pulmonary inflammation than control mice. Mechanistically, IL-3 increases innate antiviral immunity by promoting the recruitment of circulating plasmacytoid dendritic cells (pDCs) into the airways and by enhancing pDC-mediated T cell activation upon viral stimulation. Interestingly, the ability of IL-3 to improve adaptive immunity was confirmed in patients with SARS-CoV-2 infections.

Conclusion

Our study identifies IL-3 as a predictive disease marker for viral reactivation in sepsis and reveals that IL-3 improves antiviral immunity by enhancing the recruitment and the function of pDCs.

1723 Diagnostic accuracy of a novel transcriptomic classifier for bacterial and viral infections – an individual patient data meta-analysis

Aims, Objectives and Background

Arising from demographic differences between healthcare systems, patients in the emergency department (ED) present with a broad range of diagnoses and clinical severities. Independent validation of a novel diagnostic tool is critical to ensure reliable and reproducible clinical performance. So far, three independent cohort studies have validated the performance of the machine-learning classifier IMX-Bacterial/Viral/Non-infected (IMX-BVN) to diagnose bacterial and viral infections; those have been combined to facilitate an individual patient data meta-analysis of performance.

Method and Design

ED patients (n=1,277) with suspected infection from three international, observational studies (USA/Germany/Greece) were included. Of those, 661 had a unanimous (‘consensus’) ground truth of infection status established by panel adjudication. Quantitative expression of 29-signature mRNAs was measured on a NanoString nCounter® SPRINT system. The classifier BVN version 3 (IMX-BVN-3) was applied to generate scores, which fall into four discrete interpretation bands (very unlikely, unlikely, possible, very likely). Sensitivity, specificity, and corresponding nominal likelihood ratios were calculated with 95% confidence intervals for each interpretation band.

Results and Conclusion

360 patients (54.4%) were consensus adjudicated to have a bacterial infection (range: 37.9–81.2%) and 153 (23.1%) to have a viral infection (range: 15.3–44.1%). Pooled likelihood ratios of the interpretation bands for bacterial infections were (from ‘very unlikely bacterial’ to ‘very likely bacterial’) 0.082 (0.039–0.176)/0.333 (0.264–0.419)/2.244 (1.598–3.152)/9.459 (5.808–15.404), associated with a rule-in specificity of 0.947 (0.915–0.967) and a rule-out sensitivity of 0.981 (0.960–0.991) in the outer interpretation bands. Pooled likelihood ratios of the interpretation bands for viral infections were (from ‘very unlikely viral’ to ‘very likely viral’) 0.182 (0.102–0.324)/0.292 (0.181–0.471)/0.956 (0.593–1.540)/6.021 (4.636–7.821), associated with a rule-in specificity of 0.884 (0.853–0.909) and rule-out sensitivity of 0.928 (0.876–0.959).

The IMX-BVN-3 classifier exhibits strong performance in a combined cohort of patients from different geographies and settings to rule-in and rule-out patients presenting to EDs with suspected bacterial and viral infections.

A 29-MRNA HOST RESPONSE WHOLE-BLOOD SIGNATURE IMPROVES PREDICTION OF 28-DAY MORTALITY AND 7-DAY INTENSIVE CARE UNIT CARE IN ADULTS PRESENTING TO THE EMERGENCY DEPARTMENT WITH SUSPECTED ACUTE INFECTION AND/OR SEPSIS

ABSTRACT

Background: Risk stratification of emergency department patients with suspected acute infections and/or suspected sepsis remains challenging. We prospectively validated a 29-messenger RNA host response classifier for predicting severity in these patients. Methods: We enrolled adults presenting with suspected acute infections and at least one vital sign abnormality to six emergency departments in Greece. Twenty-nine target host RNAs were quantified on NanoString nCounter and analyzed with the Inflammatix Severity 2 (IMX-SEV-2) classifier to determine risk scores as low, moderate, and high severity. Performance of IMX-SEV-2 for prediction of 28-day mortality was compared with that of lactate, procalcitonin, and quick sequential organ failure assessment (qSOFA). Results: A total of 397 individuals were enrolled; 38 individuals (9.6%) died within 28 days. Inflammatix Severity 2 classifier predicted 28-day mortality with an area under the receiver operator characteristics curve of 0.82 (95% confidence interval [CI], 0.74-0.90) compared with lactate, 0.66 (95% CI, 0.54-0.77); procalcitonin, 0.67 (95% CI, 0.57-0.78); and qSOFA, 0.81 (95% CI, 0.72-0.89). Combining qSOFA with IMX-SEV-2 improved prognostic accuracy from 0.81 to 0.89 (95% CI, 0.82-0.96). The high-severity (rule-in) interpretation band of IMX-SEV-2 demonstrated 96.9% specificity for predicting 28-day mortality, whereas the low-severity (rule-out) band had a sensitivity of 78.9%. Similarly, IMX-SEV-2 alone accurately predicted the need for day-7 intensive care unit care and further boosted overall accuracy when combined with qSOFA. Conclusions: Inflammatix Severity 2 classifier predicted 28-day mortality and 7-day intensive care unit care with high accuracy and boosted the accuracy of clinical scores when used in combination.

Concurrent Change in Serum Cholinesterase Activity and Midregional-Proadrennomedullin Level Could Predict Patient Outcome following Liver Transplantation

Background: After liver transplantation (LTX), patients are susceptible to opportunistic infections resulting in reduced outcomes within the early post-transplantation period. The postoperative monitoring of LTX patients has gained much importance in recent years. However, reliable plasmatic markers predicting 90-day outcomes are still lacking. Methods: In the post hoc analysis of a prospective, observational study, butyrylcholinesterase (BChE), mid-regional proadrenomedullin (MR-proADM), as well as conventional inflammatory markers (procalcitonin, C-reactive protein) were evaluated in 93 patients at seven consecutive timepoints within the first 28 days following LTX. Results: Persistently reduced activity of BChE and elevated MR-proADM levels indicated reduced 90-day survival following LTX. Furthermore, reduced BChE and increased MR-proADM activity could indicate early post-transplantation bacterial infections, whereas conventional inflammatory biomarkers showed no diagnostic efficacy within the observation period. Conclusion: Concurrent assessment of BChE and MR-proADM activity might serve as a bedside diagnostic tool for early bacterial infections following liver transplantation. Thus, a combined utilization of the two biomarkers may be a useful tool in the risk evaluation of patients following liver transplantation.

Monocyte Metabolism and Function in Patients Undergoing Cardiac Surgery

Objective

Cardiopulmonary bypass (CPB) can lead to systemic inflammation, which is associated with higher morbidity. Therefore, we investigated the metabolism of isolated blood monocytes before and after CPB compared to healthy controls.

Methods

In this prospective, monocentric, observational study, we included 30 patients undergoing CPB and 20 controls. We isolated monocytes from heparinized blood and investigated their metabolism by using Seahorse technology before (t0), 4 h (t4), and 24 h (t24) after the start of the CPB. We also examined programmed cell death 1 ligand (PD-L1), PD-L2, V-domain Ig suppressor of T cell activation (VISTA), and human leukocyte antigen-DR isotype (HLA-DR) using fluorescence-activated cell sorting analysis. Additionally, we investigated plasma cytokine levels in patients without and after ex vivo stimulation.

Results

CPB-induced inflammatory responses are shown by significantly elevated plasma interleukin-6 levels in the CPB group compared to baseline and controls [t0: 0 ng/ml (95%CI 0-0 ng/ml); t4: 0.16 ng/ml (95%CI 0.1-0.197 ng/ml), p < 0.0001; t24: 0.11 ng/ml (95% CI 0.1-0.16 ng/ml), p < 0.0001, and controls: 0 ng/ml (95% CI 0-0 ng/ml)]. The cytokine release in the ex vivo stimulation is reduced for lipopolysaccharide stimulation at t4 [t0: 35.68 ng/ml (95% CI 22.17-46.57 ng/ml) vs. t4: 15.02 (95% CI 10.25-24.78 ng/ml), p < 0.0001]. Intracellular metabolism of monocytes after CPB showed a protracted shift to aerobic glycolysis [t0: 179.2 pmol/min (95% CI 138.0-205.1 pmol/min) vs. t24: 250.1 pmol/min (95% CI 94.8-300.2 pmol/min), p < 0.0001]. Additionally, we observed an altered metabolism in monocytes in patients undergoing cardiac surgery compared to controls even before any surgical procedure [t0: 179.2 pmol/min (95% CI 138.0-205.1) vs. controls 97.4 (95% CI 59.13-144.6 pmol/min), p = 0.0031].

Conclusion

After CPB, patients' monocytes show a shift in metabolism from oxidative phosphorylation to aerobic glycolysis, which is associated with energy-demanding and proinflammatory processes. This is the first study to show changes in monocyte immunometabolism in cardiac surgery. Monocytes of patients undergoing cardiac surgery were leaning toward aerobic glycolysis even before any surgical procedure was conducted. Leaving the question of the pathophysiological mechanisms for future studies to be investigated and paving the way for potential therapy approaches preventing inflammatory effects of CPB.

A blood-based miRNA signature with prognostic value for overall survival in advanced stage non-small cell lung cancer treated with immunotherapy

Immunotherapies have recently gained traction as highly effective therapies in a subset of late-stage cancers. Unfortunately, only a minority of patients experience the remarkable benefits of immunotherapies, whilst others fail to respond or even come to harm through immune-related adverse events. For immunotherapies within the PD-1/PD-L1 inhibitor class, patient stratification is currently performed using tumor (tissue-based) PD-L1 expression. However, PD-L1 is an accurate predictor of response in only ~30% of cases. There is pressing need for more accurate biomarkers for immunotherapy response prediction. We sought to identify peripheral blood biomarkers, predictive of response to immunotherapies against lung cancer, based on whole blood microRNA profiling. Using three well-characterized cohorts consisting of a total of 334 stage IV NSCLC patients, we have defined a 5 microRNA risk score (miRisk) that is predictive of overall survival following immunotherapy in training and independent validation (HR 2.40, 95% CI 1.37-4.19; P < 0.01) cohorts. We have traced the signature to a myeloid origin and performed miRNA target prediction to make a direct mechanistic link to the PD-L1 signaling pathway and PD-L1 itself. The miRisk score offers a potential blood-based companion diagnostic for immunotherapy that outperforms tissue-based PD-L1 staining.

Extracellular Lactate Acts as a Metabolic Checkpoint and Shapes Monocyte Function Time Dependently

Elevated blood lactate levels are frequently found in critically ill patients and thought to result from tissue hypoperfusion and cellular oxygen shortage. Considering the close relationship between immune cell function and intracellular metabolism, lactate is more than a glycolytic waste molecule but able to regulate the immune response. Our aim was to elucidate the temporal and mechanistic effect of extracellular lactate on monocytes. To this end, primary human monocytes and the human monocytic cell line MonoMac6 were stimulated with various toll-like-receptor agonists after priming with Na-L-lactate under constant pH conditions. As readout, cytokine production was measured, real-time assessment of intracellular energy pathways was performed, and intracellular metabolite concentrations were determined. Irrespective of the immunogenic stimulus, short-term Na-lactate-priming strongly reduced cytokine production capacity. Lactate and hexoses accumulated intracellularly and, together with a decreased glycolytic flux, indicate a lactate-triggered impairment of glycolysis. To counteract intracellular hyperglycemia, glucose is shunted into the branching polyol pathway, leading to sorbitol accumulation. In contrast, long-term priming with Na-L-lactate induced cellular adaption and abolished the suppressive effect. This lactate tolerance is characterized by a decreased cellular respiration due to a reduced complex-I activity. Our results indicate that exogenous lactate shapes monocyte function by altering the intracellular energy metabolism and acts as a metabolic checkpoint of monocyte activation.

Hyperspectral Imaging for the Evaluation of Microcirculatory Tissue Oxygenation and Perfusion Quality in Haemorrhagic Shock: A Porcine Study

BACKGROUND

The ultimate goal of haemodynamic therapy is to improve microcirculatory tissue and organ perfusion. Hyperspectral imaging (HSI) has the potential to enable noninvasive microcirculatory monitoring at bedside.

METHODS

HSI (Tivita® Tissue System) measurements of tissue oxygenation, haemoglobin, and water content in the skin (ear) and kidney were evaluated in a double-hit porcine model of major abdominal surgery and haemorrhagic shock. Animals of the control group (n = 7) did not receive any resuscitation regime. The interventional groups were treated exclusively with either crystalloid (n = 8) or continuous norepinephrine infusion (n = 7).

RESULTS

Haemorrhagic shock led to a drop in tissue oxygenation parameters in all groups. These correlated with established indirect markers of tissue oxygenation. Fluid therapy restored tissue oxygenation parameters. Skin and kidney measurements correlated well. High dose norepinephrine therapy deteriorated tissue oxygenation. Tissue water content increased both in the skin and the kidney in response to fluid therapy.

CONCLUSIONS

HSI detected dynamic changes in tissue oxygenation and perfusion quality during shock and was able to indicate resuscitation effectivity. The observed correlation between HSI skin and kidney measurements may offer an estimation of organ oxygenation impairment from skin monitoring. HSI microcirculatory monitoring could open up new opportunities for the guidance of haemodynamic management.

Hyperspectral imaging for perioperative monitoring of microcirculatory tissue oxygenation and tissue water content in pancreatic surgery - an observational clinical pilot study

BACKGROUND

Hyperspectral imaging (HSI) could provide extended haemodynamic monitoring of perioperative tissue oxygenation and tissue water content to visualize effects of haemodynamic therapy and surgical trauma. The objective of this study was to assess the capacity of HSI to monitor skin microcirculation and possible relations to perioperative organ dysfunction in patients undergoing pancreatic surgery.

METHODS

The hyperspectral imaging TIVITA® Tissue System was used to evaluate superficial tissue oxygenation (StO2), deeper layer tissue oxygenation (near-infrared perfusion index (NPI)), haemoglobin distribution (tissue haemoglobin index (THI)) and tissue water content (tissue water index (TWI)) in 25 patients undergoing pancreatic surgery. HSI parameters were measured before induction of anaesthesia (t1), after induction of anaesthesia (t2), postoperatively before anaesthesia emergence (t3), 6 h after emergence of anaesthesia (t4) and three times daily (08:00, 14:00, 20:00 ± 1 h) at the palm and the fingertips until the second postoperative day (t5-t10). Primary outcome was the correlation of HSI with perioperative organ dysfunction assessed with the perioperative change of SOFA score.

RESULTS

Two hundred and fifty HSI measurements were performed in 25 patients. Anaesthetic induction led to a significant increase of tissue oxygenation parameters StO2 and NPI (t1-t2). StO2 and NPI decreased significantly from t2 until the end of surgery (t3). THI of the palm showed a strong correlation with haemoglobin levels preoperatively (t2: r = 0.83, p < 0.001) and 6 h postoperatively (t4: r = 0.71, p = 0.001) but not before anaesthesia emergence (t3: r = 0.35, p = 0.10). TWI of the palm and the fingertip rose significantly between pre- and postoperative measurements (t2-t3). Higher blood loss, syndecan level and duration of surgery were associated with a higher increase of TWI. The perioperative change of HSI parameters (∆t1-t3) did not correlate with the perioperative change of the SOFA score.

CONCLUSION

This is the first study using HSI skin measurements to visualize tissue oxygenation and tissue water content in patients undergoing pancreatic surgery. HSI was able to measure short-term changes of tissue oxygenation during anaesthetic induction and pre- to postoperatively. TWI indicated a perioperative increase of tissue water content. Perioperative use of HSI could be a useful extension of haemodynamic monitoring to assess the microcirculatory response during haemodynamic therapy and major surgery.

TRIAL REGISTRATION

German Clinical Trial Register, DRKS00017313 on 5 June 2019.

[Sepsis in out-of-hospital emergency medicine]

Background

Sepsis is a challenge in emergency medicine, as this life-threatening organ dysfunction, caused by a dysregulated host response to an infection, presents manifold and therefore is often recognized too late.

Objectives

Recently published surviving sepsis campaign and German S3 guidelines provide recommendations for diagnosis and therapy of sepsis in an in-hospital or intensive care setting, but do not particularly address out-of-hospital emergency medical care. We aim to work out the evidence base with regard to the out-of-hospital care of patients with suspected sepsis and to derive treatment recommendations for emergency medical services.

Conclusions

Therapy of sepsis and septic shock is summarized in bundles, whereby the first bundle should ideally be completed within the first hour-in analogy to "golden hour" concepts in other emergency medical entities, such as trauma care. In the out-of-hospital setting, therapy focuses on securing vital parameters, according to the ABCDE scheme, with a particular focus on volume therapy. Further procedures within the 1 h bundle, such as lactate measurement, obtaining microbiological samples, and starting an anti-infective therapy, are broadly available in hospital only. The aim is to control the site of infection as soon as possible. Therefore, an appropriate designated hospital should be chosen carefully and informed in advance, in order to initiate and pave the way for further clinical diagnostic and treatment paths. Moreover, structured and target-oriented handovers, as well as regular training, are required.

Antiproliferative effect of GTS-21 in glioblastoma cells

Glioblastoma multiforme (GBM) is the most common malignant brain tumour in adults. The poor prognosis and short median overall survival of patients with GBM is associated with resistance to therapy after surgical and adjuvant treatment. The expression of various acetylcholine receptors (AChR) in GBM has been widely reported. The present study aimed to investigate the expression of cholinergic system-related genes in primary GBM and to explore the antiproliferative effect of 3-(2,4-dimethoxybenzylidene) anabaseine (GTS-21) in GBM cell lines. Therefore, the expression of 28 genes associated with the cholinergic system was detected using a customized RT² Profiler PCR Array in 44 GBM and 5 healthy control brain tissue samples. In addition, the activity of GTS-21, an alpha 7 subunit nicotinic AChR (α7 nAChR) agonist, and that of α-bungarotoxin (α-BTX), an α7 nAChR antagonist, was determined in primary and established GBM cells. Therefore, the A172, U87 and G28 cell lines and primary GBM cells were treated with GTS-21, ACh or nicotine. Cell viability was evaluated using MTT assay at 24, 48 and 72 h following cell treatment with the corresponding compounds. The results revealed that the expression of cholinergic system-related components was notably downregulated, except that of cholinergic receptor nicotinic alpha 7 subunit (CHRNA7), in primary GBM and U87 cells. However, the dominant-negative duplicate form of CHRNA7 was also downregulated. Furthermore, A172 and G28 cells exhibited a heterogeneous gene expression pattern. Additionally, GTS-21 inhibited the proliferation of GBM cells in a dose- and time-dependent manner. Interestingly, treatment with α-BTX restored the proliferation of U87 cells, but not that of A172 and G28 cells. Collectively, the findings of the present study suggested that GTS-21 may inhibit the proliferation of GBM cells and may therefore serve as a novel therapeutic approach to the treatment of GBM, which warrants further investigation.

Low-Density Granulocyte Contamination From Peripheral Blood Mononuclear Cells of Patients With Sepsis and How to Remove It - A Technical Report

Elucidating the mechanisms contributing to the dysregulated host response to infection as part of the syndrome is a current challenge in sepsis research. Peripheral blood mononuclear cells are widely used in immunological studies. Density gradient centrifugation, a common method, is of limited use for blood drawn from patients with sepsis. A significant number of low-density granulocytes co-purify contributing to low purity of isolated peripheral blood mononuclear cells. Whole blood anticoagulated with lithium heparin was drawn from patients with sepsis (n=14) and healthy volunteers (n=11). Immediately after drawing, the plasma fraction was removed and PBMC were isolated from the cellular fraction by density gradient centrifugation. Samples derived from patients with sepsis were subsequently incubated with cluster of differentiation 15 MicroBeads and granulocytes were depleted using magnetic-activated cell sorting. Core cellular functions as antigen presentation and cytokine secretion were analyzed in cells isolated from healthy volunteers (n=3) before and after depletion to confirm consistent functionality. We report here that depleting CD15⁺ cells after density gradient centrifugation is a feasible way to get rid of the low-density granulocyte contamination. Afterwards, the purity of isolated, functionally intact peripheral blood mononuclear cells is comparable to healthy volunteers. Information on the isolation purity and identification of the containing cell types are necessary for good comparability between different studies. Depletion of CD15⁺ cells after density gradient centrifugation is an easy but highly efficient way to gain a higher quality and more reliability in studies using peripheral blood mononuclear cells from septic patients without affecting the functionality of the cells.

FC 043SOLUBLE UROKINASE PLASMINOGEN ACTIVATOR RECEPTOR (SUPAR) DETERMINES OUTCOMES IN CLINICAL AND EXPERIMENTAL SEPTIC ACUTE KIDNEY INJURY

Background and Aims

Sepsis is the main contributor to the development of acute kidney injury (AKI) in critically ill patients. Plasma soluble urokinase plasminogen activator receptor (suPAR) is a circulating risk factor for AKI and a new prognostic marker for renal outcome prediction. We analyzed the pathophysiological role and kinetic properties of suPAR in septic AKI in critically ill patients and in a murine model of septic AKI.

Method

200 critically ill patients were enrolled prospectively after meeting Sepsis-3 criteria. Serum suPAR levels were measured at 0, 12, 24, 48, 72, 96, 120 and 168-hour after enrollment (n=1440) and the need for RRT within 7 days (predefined criteria) was assessed as the primary outcome measure. Polybacterial sepsis was induced by cecal slurry injection in three mouse strains, respectively wild type (WT, N=16), uPAR-knockout (KO, N=15), and suPAR transgenic overexpression (OE, N=14).

Results

No or mild AKI occurred in 62 patients (31.0%), moderate or severe AKI without the need for RRT in 102 patients (51.0%), criteria for RRT were met in 36 patients (18.0%) and 7 patients (3.5%) died within the 7-day period. Compared to all other maximum AKI stages and AKI disease courses within 7 days, patients requiring RRT showed significantly higher suPAR levels at all time-points. Patients with suPAR levels ≥ 12.7 ng/mL (highest quartile) had an unadjusted odds ratio (OR) of 9.73 (95% confidence interval [CI], 4.31-21.98) and an adjusted odds ratio of 5.22 (95% CI, 2.16-12.65) for the need for RRT; and 7.47 (95% CI, 3.54-15.74) and 4.44 (95% CI, 1.98-9.97) for RRT or death within 7 days compared to patients with levels &lt; 12.7 ng/mL. Compared to KO mice, WT and OE mice showed a significantly greater impairment of renal function, structure and tubular apoptosis 24 hours after induction of sepsis. The inflammation levels with respect to Interleukin 6 were comparable between different strains. Kaplan-Meier analysis revealed a survival benefit of KO mice over OE mice within 24h (86.7% vs. 50.0%, p=0.033).

Conclusion

SuPAR distinguishes between divergent AKI stages/courses and the need for RRT at any time within 7 days after sepsis diagnosis. Our experimental data suggest that suPAR is a pathophysiological driver of septic AKI and may serve as a target for future interventional strategies.

Comparison of machine-learning methodologies for accurate diagnosis of sepsis using microarray gene expression data

We investigate the feasibility of molecular-level sample classification of sepsis using microarray gene expression data merged by in silico meta-analysis. Publicly available data series were extracted from NCBI Gene Expression Omnibus and EMBL-EBI ArrayExpress to create a comprehensive meta-analysis microarray expression set (meta-expression set). Measurements had to be obtained via microarray-technique from whole blood samples of adult or pediatric patients with sepsis diagnosed based on international consensus definition immediately after admission to the intensive care unit. We aggregate trauma patients, systemic inflammatory response syndrome (SIRS) patients, and healthy controls in a non-septic entity. Differential expression (DE) analysis is compared with machine-learning-based solutions like decision tree (DT), random forest (RF), support vector machine (SVM), and deep-learning neural networks (DNNs). We evaluated classifier training and discrimination performance in 100 independent iterations. To test diagnostic resilience, we gradually degraded expression data in multiple levels. Clustering of expression values based on DE genes results in partial identification of sepsis samples. In contrast, RF, SVM, and DNN provide excellent diagnostic performance measured in terms of accuracy and area under the curve (>0.96 and >0.99, respectively). We prove DNNs as the most resilient methodology, virtually unaffected by targeted removal of DE genes. By surpassing most other published solutions, the presented approach substantially augments current diagnostic capability in intensive care medicine.

Perioperative changes in the plasma metabolome of patients receiving general anesthesia for pancreatic cancer surgery

Background: Modern anesthesia strives to offer personalized concepts to meet the patient’s individual needs in sight of clinical outcome. Still, little is known about the impact of anesthesia on the plasma metabolome, although many metabolites have been shown to modulate the function of various immune cells, making it particularly interesting in the context of oncological surgery. In this study longitudinal dynamics in the plasma metabolome during general anesthesia in patients undergoing pancreatic surgery were analyzed.

Materials and Methods: Prospective, observational study with 10 patients diagnosed with pancreatic (pre-) malignancy and subjected to elective resection surgery under general anesthesia. Plasma metabolites (n = 630) were quantified at eight consecutive perioperative timepoints using mass spectrometry-based targeted metabolomics.

Results: 39 metabolites significantly changed during the perioperative period. Tryptophan concentrations decreased by 45% with the maximum decrease after anesthesia induction (p = 6.24E-07), while taurine synthesis increased (p = 1.46E-04). Triacylglycerides and lysophosphatidylcholines were significantly reduced with increased liberation of free monounsaturated fatty acids (p = 0.03). Carnitine levels decreased significantly (p = 9.30E-04).

Conclusions: The major finding of this study was perioperative tryptophan depletion and increased taurine synthesis. Both are essential for immune cell function and are therefore of significant interest for perioperative management. Further studies are needed to identify influencing anesthetic factors.

The COVID-19 puzzle: deciphering pathophysiology and phenotypes of a new disease entity

The zoonotic SARS-CoV-2 virus that causes COVID-19 continues to spread worldwide, with devastating consequences. While the medical community has gained insight into the epidemiology of COVID-19, important questions remain about the clinical complexities and underlying mechanisms of disease phenotypes. Severe COVID-19 most commonly involves respiratory manifestations, although other systems are also affected, and acute disease is often followed by protracted complications. Such complex manifestations suggest that SARS-CoV-2 dysregulates the host response, triggering wide-ranging immuno-inflammatory, thrombotic, and parenchymal derangements. We review the intricacies of COVID-19 pathophysiology, its various phenotypes, and the anti-SARS-CoV-2 host response at the humoral and cellular levels. Some similarities exist between COVID-19 and respiratory failure of other origins, but evidence for many distinctive mechanistic features indicates that COVID-19 constitutes a new disease entity, with emerging data suggesting involvement of an endotheliopathy-centred pathophysiology. Further research, combining basic and clinical studies, is needed to advance understanding of pathophysiological mechanisms and to characterise immuno-inflammatory derangements across the range of phenotypes to enable optimum care for patients with COVID-19.

Bedside hyperspectral imaging indicates a microcirculatory sepsis pattern - an observational study

INTRODUCTION

Microcirculatory alterations are key mechanisms in sepsis pathophysiology leading to tissue hypoxia, edema formation, and organ dysfunction. Hyperspectral imaging (HSI) is an emerging imaging technology that uses tissue-light interactions to evaluate biochemical tissue characteristics including tissue oxygenation, hemoglobin content and water content. Currently, clinical data for HSI technologies in critical ill patients are still limited.

METHODS AND ANALYSIS

TIVITA® Tissue System was used to measure Tissue oxygenation (StO2), Tissue Hemoglobin Index (THI), Near Infrared Perfusion Index (NPI) and Tissue Water Index (TWI) in 25 healthy volunteers and 25 septic patients. HSI measurement sites were the palm, the fingertip, and a suprapatellar knee area. Septic patients were evaluated on admission to the ICU (E), 6 h afterwards (E+6) and three times a day (t3-t9) within a total observation period of 72 h. Primary outcome was the correlation of HSI results with daily SOFA-scores.

RESULTS

Serial HSI at the three measurement sites in healthy volunteers showed a low mean variance expressing high retest reliability. HSI at E demonstrated significantly lower StO2 and NPI as well as higher TWI at the palm and fingertip in septic patients compared to healthy volunteers. StO2 and TWI showed corresponding results at the suprapatellar knee area. In septic patients, palm and fingertip THI identified survivors (E-t4) and revealed predictivity for 28-day mortality (E). Fingertip StO2 and THI correlated to SOFA-score on day 2. TWI was consistently increased in relation to the TWI range of healthy controls during the observation time. Palm TWI correlated positively with SOFA scores on day 3.

DISCUSSION

HSI results in septic patients point to a distinctive microcirculatory pattern indicative of reduced skin oxygenation and perfusion quality combined with increased blood pooling and tissue water content. THI might possess risk-stratification properties and TWI could allow tissue edema evaluation in critically ill patients.

CONCLUSION

HSI technologies could open new perspectives in microcirculatory monitoring by visualizing oxygenation and perfusion quality combined with tissue water content in critically ill patients - a prerequisite for future tissue perfusion guided therapy concepts in intensive care medicine.

Bridging animal and clinical research during SARS-CoV-2 pandemic: A new-old challenge

Many milestones in medical history rest on animal modeling of human diseases. The SARS-CoV-2 pandemic has evoked a tremendous investigative effort primarily centered on clinical studies. However, several animal SARS-CoV-2/COVID-19 models have been developed and pre-clinical findings aimed at supporting clinical evidence rapidly emerge. In this review, we characterize the existing animal models exposing their relevance and limitations as well as outline their utility in COVID-19 drug and vaccine development. Concurrently, we summarize the status of clinical trial research and discuss the novel tactics utilized in the largest multi-center trials aiming to accelerate generation of reliable results that may subsequently shape COVID-19 clinical treatment practices. We also highlight areas of improvement for animal studies in order to elevate their translational utility. In pandemics, to optimize the use of strained resources in a short time-frame, optimizing and strengthening the synergy between the preclinical and clinical domains is pivotal.

Detection of In Vivo Inflammasome Activation for Predicting Sepsis Mortality

Sepsis is a severe life-threatening syndrome caused by dysregulated host responses to infection. Biomarkers that allow for monitoring the patient's immune status are needed. Recently, a flow cytometry-based detection of in vivo inflammasome activation by formation of cytoplasmic aggregates of ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) has been proposed. Here we report on the frequency of ASC-speck⁺ leukocytes correlating with the survival of sepsis. 25 patients with sepsis were sampled consecutively for 7 days. Blood, serum samples and patient data were collected according to the guidelines of the PredARRT-Sep-Trial. Flow cytometric analysis was performed on fresh whole blood samples to investigate the formation of ASC-specks in leukocyte subsets. Serum samples were analyzed for production of IL-1ß, IL-18 and additional inflammatory markers. ASC-speck formation was found to be increased in leukocytes from sepsis patients compared to healthy donor controls. The absolute number of ASC-speck⁺ neutrophils peaked on day 1. For monocytes, the highest percentage and maximum absolute number of ASC-speck⁺ cells were detected on day 6 and day 7. Inflammatory cytokines were elevated on day 1 and declined thereafter, with exception of IL-18. Survival analysis showed that patients with lower absolute numbers of ASC-speck⁺ monocytes (<1,650 cells/ml) on day 6 had a lower probability to survive, with a hazard ratio (HR) of 10.178. Thus, the frequency of ASC-speck⁺ monocytes on day 6 after onset of sepsis may serve to identify patients at risk of death from sepsis.

Impact of Different Positive End-Expiratory Pressures on Lung Mechanics in the Setting of Moderately Elevated Intra-Abdominal Pressure and Acute Lung Injury in a Porcine Model

The effects of a moderately elevated intra-abdominal pressure (IAP) on lung mechanics in acute respiratory distress syndrome (ARDS) have still not been fully analyzed. Moreover, the optimal positive end-expiratory pressure (PEEP) in elevated IAP and ARDS is unclear. In this paper, 18 pigs under general anesthesia received a double hit lung injury. After saline lung lavage and 2 h of injurious mechanical ventilation to induce an acute lung injury (ALI), an intra-abdominal balloon was filled until an IAP of 10 mmHg was generated. Animals were randomly assigned to one of three groups (group A = PEEP 5, B = PEEP 10 and C = PEEP 15 cmH₂O) and ventilated for 6 h. We measured end-expiratory lung volume (EELV) per kg bodyweight, driving pressure (ΔP), transpulmonary pressure (ΔP_L), static lung compliance (C_stat), oxygenation (P/F ratio) and cardiac index (CI). In group A, we found increases in ΔP (22 ± 1 vs. 28 ± 2 cmH₂O; p = 0.006) and ΔP_L (16 ± 1 vs. 22 ± 2 cmH₂O; p = 0.007), with no change in EELV/kg (15 ± 1 vs. 14 ± 1 mL/kg) when comparing hours 0 and 6. In group B, there was no change in ΔP (26 ± 2 vs. 25 ± 2 cmH₂O), ΔP_L (19 ± 2 vs. 18 ± 2 cmH₂O), C_stat (21 ± 3 vs. 21 ± 2 cmH₂O/mL) or EELV/kg (12 ± 2 vs. 13 ± 3 mL/kg). ΔP and ΔP_L were significantly lower after 6 h when comparing between group C and A (21 ± 1 vs. 28 ± 2 cmH₂O; p = 0.020) and (14 ± 1 vs. 22 ± 2 cmH₂O; p = 0.013)). The EELV/kg increased over time in group C (13 ± 1 vs. 19 ± 2 mL/kg; p = 0.034). The P/F ratio increased in all groups over time. CI decreased in groups B and C. The global lung injury score did not significantly differ between groups (A: 0.25 ± 0.05, B: 0.21 ± 0.02, C: 0.22 ± 0.03). In this model of ALI, elevated IAP, ΔP and ΔP_L increased further over time in the group with a PEEP of 5 cmH₂O applied over 6 h. This was not the case in the groups with a PEEP of 10 and 15 cmH₂O. Although ΔP and ΔP_L were significantly lower after 6 hours in group C compared to group A, we could not show significant differences in histological lung injury score.

The anesthetist's choice of inhalational vs. intravenous anesthetics has no impact on survival of glioblastoma patients

Recent data suggest that the type of anesthesia used during the resection of solid tumors impacts the long-term survival of patients favoring total-intravenous-anesthesia (TIVA) over inhalative-anesthesia (INHA). Here we sought to query this impact on survival in patients undergoing resection of glioblastoma (GBM). All patients receiving elective resection of a newly diagnosed, isocitrate-dehydrogenase-1-(IDH1)-wildtype GBM under general anesthesia between January 2010 and June 2017 in the Department of Neurosurgery, Heidelberg University Hospital, were included. Patients were grouped according to the applied anesthetic technique. To adjust for potential prognostic confounders, patients were matched in a 1:2 ratio (TIVA vs. INHA), taking into account the known prognostic factors: age, extent of resection, O-6-methylguanine-DNA-methyltransferase-(MGMT)-promoter-methylation-status, pre-operative Karnofsky-performance-index and adjuvant radio- and chemotherapy. The primary endpoint was progression-free-survival (PFS) and the secondary endpoint was overall-survival (OS). In the study period, 576 patients underwent resection of a newly diagnosed, IDH-wildtype GBM. Patients with incomplete follow-up-data, on palliative treatment, having emergency or awake surgery; 54 patients remained in the TIVA-group and 417 in the INHA-group. After matching, 52 patients remained in the TIVA-group and 92 in the INHA-group. Median PFS was 6 months in both groups. The median OS was 13.5 months in the TIVA-group and 13.0 months in the INHA-group. No significant survival differences associated with the type of anesthesia were found either before or after adjustment for known prognostic factors. This retrospective study supports the notion that the current anesthetic approaches employed during the resection of IDH-wildtype GBM do not impact patient survival.

Sphingosine‑1‑phosphate analogue FTY720 exhibits a potent anti‑proliferative effect on glioblastoma cells

Sphingosine‑1‑phosphate (S1P) plays a key role in cell survival, growth, migration, and in angiogenesis. In glioma, it triggers the activity of the S1P‑receptor 1 and of the sphingosine kinase 1; thus influencing the survival rate of patients. The aim of the present study was to investigate the anti‑proliferative effect of the S1P analogue FTY720 (fingolimod) in glioblastoma (GBM) cells. A172, G28, and U87 cells were incubated with micromolar concentrations of FTY720 or temozolomide (TMZ) for 24 to 72 h. Proliferation and half maximal inhibitory concentration (IC50) were determined by using the xCELLigence system. FACS analysis was performed to check the cell cycle distribution of the cells after a 72‑h incubation with FTY720. This was then compared to TMZ‑incubated and to untreated cells. Gene expression was detected by RT‑qPCR in A172, G28, U87 and three primary GBM‑derived cell lines. FTY720 was able to reduce the number of viable cells. The IC50 value was 4.6 µM in A172 cells, 17.3 µM in G28 cells, and 25.2 µM in U87 cells. FTY720 caused a significant arrest of the cell cycle in all cells and stabilized or over‑expressed the level of AKT1, MAPK1, PKCE, RAC1, and ROCK1 transcripts. The TP53 transcript level remained stable or was downregulated after treatment with FTY720. FTY720 may be a promising target drug for the treatment of GBM, as it has a strong anti‑proliferative effect on GBM cells.

Bedside hyperspectral imaging for the evaluation of microcirculatory alterations in perioperative intensive care medicine: a study protocol for an observational clinical pilot study (HySpI-ICU)

INTRODUCTION

Normalisation of macrocirculatory parameters during resuscitation therapy does not guarantee the restoration of microcirculatory perfusion in critical illness due to haemodynamic incoherence. Persistent microcirculatory abnormalities are associated with severity of organ dysfunction and mandate the development of bedside microcirculatory monitoring. A novel hyperspectral imaging (HSI) system can visualise changes in skin perfusion, oxygenation and water content at the bedside. We aim to evaluate the effectiveness of HSI for bedside monitoring of skin microcirculation and the association of HSI parameters with organ dysfunction in patients with sepsis and major abdominal surgery.

METHODS AND ANALYSIS

Three independent groups will be assessed and separately analysed within a clinical prospective observational study: (1) 25 patients with sepsis or septic shock (according to sepsis-3 criteria), (2) 25 patients undergoing pancreatic surgery and (3) 25 healthy controls. Patients with sepsis and patients undergoing pancreatic surgery will receive standard therapy according to local protocols derived from international guidelines. In addition, cardiac output of perioperative patients and patients with sepsis will be measured. Healthy controls undergo one standardised evaluation. The TIVITA Tissue System is a novel HSI system that uses the visible and near-infrared spectral light region to determine tissue microcirculatory parameters. HSI analysis (hand/knee) will be done in parallel to haemodynamic monitoring within defined intervals during a 72-hour observation period. HSI data will be correlated with the Sequential Organ Failure Assessment score, global haemodynamics, inflammation and glycocalyx markers, surgical complications and 30-day outcome.

ETHICS AND DISSEMINATION

The protocol has been approved by the local ethics committee of the University of Heidelberg (S-148/2019). Study results will be submitted to peer-reviewed journals and medical conferences.

TRIAL REGISTRATION NUMBER

DRKS00017313; Pre-results.

Soluble intercellular adhesion molecule (ICAM)-1 detects invasive fungal infections in patients following liver transplantation

PURPOSE

Despite antifungal prophylaxis, liver transplanted patients are endangered by invasive fungal infections (IFI). Routinely used microbiological procedures are hallmarked by significant weaknesses, which may lead to a delay in antifungal treatment.

METHODS

Culture-based fungal findings, routinely used biomarkers of infection/inflammation (e.g., procalcitonin or C-reactive protein), as well as corresponding plasma concentrations of soluble Intercellular Adhesion Molecule (ICAM)-1 were analysed in 93 patients during a period of 28 days following liver transplantation (LTX).

RESULTS

Plasmatic sICAM-1 was significantly elevated in patients affected by an IFI within the first 28 days in comparison to fungally colonised or unobtrusive LTX patients. sICAM-1 might therefore be helpful for the identification of IFI patients after LTX (e.g., Receiver Operating Characteristic (ROC)-Area Under the Curve (AUC): 0.714 at 14d after LTX). The diagnostic performance of sICAM-1 was further improved by its combined use with different other IFI biomarkers (e.g., midregional proadrenomedullin).

CONCLUSION

The diagnostic deficiencies of routinely used microbiological procedures for IFI detection in patients after LTX may be reduced by plasmatic sICAM-1 measurements. Clinical Trial Notation. German Clinical Trials Register: DRKS00005480.

Sevoflurane depletes macrophages from the melanoma microenvironment

BACKGROUND

With more than 18 million annual new cases, cancer belongs to the major challenges of modern healthcare. Surgical resection of solid tumours under general anaesthesia is the prime therapy. Different aspects of anaesthesia are under discussion to independently influence the long-term outcome of cancer patients. Most recently, the commonly used volatile anaesthetics like sevoflurane have entered the spotlight, as retrospective studies suggest a detrimental outcome in certain cancer aetiologies with sparse mechanistic understanding. Our objective was to investigate this concept in a murine melanoma model, herein comparing the consequence of inhalative and injection anesthesia on tumour composition and growth.

METHODS

We used a murine model of malignant melanoma in male, adult C57BL/6 mice (n = 92), induced by the subcutaneous injection of B16-F10 cells. We either exposed the melanoma cells to sevoflurane before implantation or subjected the animals to single or double anaesthesia with either volatile or injection drugs. After a maximum follow-up of 4 weeks, leucocytes within the tumour microenvironment (TME) were comprehensively analysed by flow cytometry with focus on tumor-associated macrophages (TAM).

RESULTS

We found that exposure of melanoma cells to sevoflurane before implantation induced long-lasting transcriptome changes and aggravated tumour growth, without extensive changes of the TME. Contrastingly, both a single and double anaesthesia with sevoflurane led to a significant reduction of TAMs (injection vs. sevoflurane: 2,0 vs. 0.3% and 1.2 vs. 0.6%, respectively), whilst increasing PD-L1 expression on the remaining cells (mean fluorescent intensity injection vs. sevoflurane: 3,804 vs. 7,143 and 9,090 vs. 32,228, respectively). No changes in tumour growth were observed in these groups.

CONCLUSION

In sharp contrast to the detrimental impact of sevoflurane on patients' outcome reported in retrospective clinical studies, we propose here that sevoflurane might actually exert a beneficial effect by decreasing TAMs within the TME, rendering the tumour again susceptible for cytotoxic T cells and immunotherapies. Further research is warranted to delineate, how these results translate into the clinic.

Preoperative neutrophil to lymphocyte ratio and platelet to lymphocyte ratio are associated with major adverse cardiovascular and cerebrovascular events in coronary heart disease patients undergoing non-cardiac surgery

BACKGROUND

Preoperative risk prediction in patients at elevated cardiovascular risk shows limited accuracy. Platelet to lymphocyte ratio (PLR) and neutrophil to lymphocyte ratio (NLR) indicate systemic inflammation. Both have been investigated for outcome prediction in the field of oncology and cardiovascular medicine, as well as risk prediction of adverse cardiovascular events in non-surgical patients at increased cardiovascular risk.

METHODS

For this post-hoc analysis, we included all 38 coronary heart disease patients from the Leukocytes and Cardiovascular Perioperative Events cohort-1 study scheduled for elective non-cardiac surgery. We evaluated preoperative differential blood counts for association with major adverse cardiovascular and cerebrovascular events (MACCE) defined as the composite endpoint of death, myocardial ischemia, myocardial infarction, myocardial injury after non-cardiac surgery, or embolic or thrombotic stroke within 30 days after surgery. We used Youden's index to calculate cut-off values for PLR and NLR. Additive risk-predictive values were assessed using receiver operating characteristic curve and net reclassification (NRI) improvement analyses.

RESULTS

Patients with the composite endpoint MACCE had higher PLR and NLR (309 [206; 380] vs. 160 [132; 203], p = 0.001; 4.9 [3.5; 8.1] vs. 2.6 [2.2; 3.4]), p = 0.001). Calculated cut-offs for PLR > 204.4 and NLR > 3.1 were associated with increased risk of 30-day MACCE (OR 7, 95% CI [1.2; 44.7], p = 0.034; OR 36, 95% CI [1.8; 686.6], p = 0.001). Furthermore, NLR improved risk prediction in coronary heart disease patients undergoing non-cardiac surgery when combined with hs-cTnT or NT-proBNP (NRI _total = 0.23, p = 0.008, NRI _total = 0.26, p = 0.005).

CONCLUSIONS

Both PLR and NLR were associated with perioperative cardiovascular adverse events in coronary heart disease patients. NLR proved to be of additional value for preoperative risk stratification. Both PLR and NLR could be used as inexpensive and broadly available tools for perioperative risk assessment.

TRIAL REGISTRATION

NCT02874508, August 22, 2016.

Pulmonary microbiome patterns correlate with the course of the disease in patients with sepsis-induced ARDS following major abdominal surgery

BACKGROUND

Patients with sepsis-induced Acute Respiratory Distress Syndrome (ARDS) are hallmarked by high mortality rates. Early, targeted antibiotic therapy is crucial for patients' survival. The clinical use of a Next Generation Sequencing (NGS)-based approach for pathogen identification may lead to an improved diagnostic performance. Therefore, the objective of this study was to examine changes in the pulmonary-microbiome and resulting influences on patients' outcome in septic ARDS, but also to compare NGS- and culture-based diagnostic methods for pathogen identification.

METHODS

In total, 30 patients in two groups were enrolled in the study: (1) 15 septic ARDS patients following major abdominal surgery and (2) 15 patients undergoing oesophageal resection serving as controls. In the ARDS group, blood samples were collected at ARDS onset as well as 5 days and 10 days afterwards. At the same timepoints, bronchoalveolar lavages (BAL) were performed to collect epithelial lining fluid for culture-, as well as NGS-based analyses and to evaluate longitudinal changes in the pulmonary microbiome. In the control group, only one BAL and one blood sample were collected.

RESULTS

ARDS patients showed a significantly reduced α-diversity (p=0.007**) and an increased dominance (p=0.012*) in their pulmonary-microbiome. The α-diversity-index correlated with the length of stay in the intensive care unit (p-value=0.015) and the need for mechanical ventilation (p-value=0.009). In 42.9% of all ARDS patients, culture-based results were negative, while NGS findings indicated bacterial colonization.

CONCLUSION

Sepsis-induced ARDS is associated with a significant dysbiosis of patients' pulmonary-microbiome, which is closely correlated with the clinical course of the disease.

TRIAL REGISTRATION

This prospective, observational pilot study was approved by the Ethics Committee of the Medical Faculty of Heidelberg (trial code no. S-063/2015) and was prospectively registered in the German clinical trials register (DRKS-ID: DRKS00008317 prospectively registered: 28.10.2015). All study patients or their legal representatives signed written informed consent.

Effect of moderate elevated intra-abdominal pressure on lung mechanics and histological lung injury at different positive end-expiratory pressures

INTRODUCTION

Intra-abdominal hypertension (IAH) is a well-known phenomenon in critically ill patients. Effects of a moderately elevated intra-abdominal pressure (IAP) on lung mechanics are still not fully analyzed. Moreover, the optimal positive end-expiratory pressure (PEEP) in elevated IAP is unclear.

METHODS

We investigated changes in lung mechanics and transformation in histological lung patterns using three different PEEP levels in eighteen deeply anesthetized pigs with an IAP of 10 mmHg. After establishing the intra-abdominal pressure, we randomized the animals into 3 groups. Each of n = 6 (Group A = PEEP 5, B = PEEP 10 and C = PEEP 15 cmH2O). End-expiratory lung volume (EELV/kg body weight (bw)), pulmonary compliance (Cstat), driving pressure (ΔP) and transpulmonary pressure (ΔPL) were measured for 6 hours. Additionally, the histological lung injury score was calculated.

RESULTS

Comparing hours 0 and 6 in group A, there was a decrease of EELV/kg (27±2 vs. 16±1 ml/kg; p<0.05) and of Cstat (42±2 vs. 27±1 ml/cmH2O; p<0.05) and an increase of ΔP (11±0 vs. 17±1 cmH2O; p<0.05) and ΔPL (6±0 vs. 10±1 cmH2O; p<0.05). In group B, there was no significant change in EELV/kg (27±3 vs. 24±3 ml/kg), but a decrease in Cstat (42±3 vs. 32±1 ml/cmH20; p<0.05) and an increase in ΔP (11±1 vs. 15±1 cmH2O; p<0.05) and ΔPL (5±1 vs. 7±0 cmH2O; p<0.05). In group C, there were no significant changes in EELV/kg (27±2 vs. 29±3 ml/kg), ΔP (10±1 vs. 12±1 cmH2O) and ΔPL (5±1 vs. 7±1 cmH2O), but a significant decrease of Cstat (43±1 vs. 37±1 ml/cmH2O; p<0.05). Histological lung injury score was lowest in group B.

CONCLUSIONS

A moderate elevated IAP of 10 mmHg leads to relevant changes in lung mechanics during mechanical ventilation. In our study, a PEEP of 10 cmH2O was associated with a lower lung injury score and was able to overcome the IAP induced alterations of EELV.

Molecular and biomarker-based diagnostics in early sepsis: current challenges and future perspectives

Introduction: Sepsis, defined as a life-threatening organ dysfunction resulting from dysregulated host response to infection, is still a major challenge for healthcare systems. Early diagnosis is highly needed, yet challenging, due to the non-specificity of clinical symptoms. Rapid and targeted application of therapy strategies is crucial for patient's outcome.Areas covered: Faster and better diagnostics with high accuracy is promised by novel host response biomarkers and a wide variety of direct pathogen identification technologies, which have emerged over the last years. This review will cover both - host response-guided diagnostics and methods for direct pathogen detection. Some of the markers and technologies are already market-ready, others are more likely aspirants. We will discuss them in terms of their performance and benefit for use in clinical diagnostics.Expert opinion: Latest technological advances enable the development of promising diagnostic tests, detecting the host response as well as identifying pathogens without the need of cultivation. However, the syndrome's heterogeneity makes it difficult to develop a universal test suitable for routine use. Moreover, the robustness of the biomarkers and technologies still has to be verified. Combining these technologies and clinical routine parameters with bioinformatic methods (e.g., machine-learning algorithms) may revolutionize sepsis diagnostics.

Frontline Science: Low regulatory T cells predict perioperative major adverse cardiovascular and cerebrovascular events after noncardiac surgery

Immune cells drive atherosclerotic lesion progression and plaque destabilization. Coronary heart disease patients undergoing noncardiac surgery are at risk for perioperative major adverse cardiac and cerebrovascular events (MACCE). It is unclear whether differential leukocyte subpopulations contribute to perioperative MACCE and thereby could aid identification of patients prone to perioperative cardiovascular events. First, we performed a hypothesis-generating post hoc analysis of the LeukoCAPE-1 study (n = 38). We analyzed preoperative counts of 6 leukocyte subpopulations in coronary heart disease patients for association with MACCE (composite of cardiac death, myocardial infarction, myocardial ischemia, myocardial injury after noncardiac surgery, thromboembolic stroke) within 30 d after surgery. Regulatory T cells (Tregs) were the only leukocyte subgroup associated with MACCE. We found reduced Tregs in patients experiencing MACCE versus no-MACCE (0.02 [0.01; 0.03] vs. 0.04 [0.03; 0.05] Tregs nl^-1 , P = 0.002). Using Youden index, we derived the optimal threshold value for association with MACCE to be 0.027 Tregs nl^-1 . Subsequently, we recruited 233 coronary heart disease patients for the prospective, observational LeukoCAPE-2 study and independently validated this Treg cutoff for prediction of MACCE within 30 d after noncardiac surgery. After multivariate logistic regression, Tregs < 0.027 cells nl^-1 remained an independent predictor for MACCE (OR = 2.54 [1.22; 5.23], P = 0.012). Tregs improved risk discrimination of the revised cardiac risk index based on ΔAUC (area under the curve; ΔAUC = 0.09, P = 0.02), NRI (0.26), and IDI (0.06). Preoperative Treg levels below 0.027 cells nl^-1 predicted perioperative MACCE and can be measured to increase accuracy of established preoperative cardiac risk stratification in coronary heart disease patients undergoing noncardiac surgery.

Ivor Lewis esophagectomy patients are particularly vulnerable to respiratory impairment - a comparison to major lung resection

Pulmonary complications and a poor clinical outcome are common in response to transthoracic esophagectomy, but their etiology is not well understood. Clinical observation suggests that patients undergoing pulmonary resection, a surgical intervention with similarities to the thoracic part of esophagectomy, fare much better, but this has not been investigated in detail. A retrospective single-center analysis of 181 consecutive patients after right-sided thoracotomy for either Ivor Lewis esophagectomy (n = 83) or major pulmonary resection (n = 98) was performed. An oxygenation index <300 mm Hg was used to indicate respiratory impairment. When starting surgery, respiratory impairment was seen more frequently in patients undergoing major pulmonary resection compared to esophagectomy patients (p = 0.009). On postoperative days one to ten, however, esophagectomy caused higher rates of respiratory impairment (p < 0.05) resulting in a higher cumulative incidence of postoperative respiratory impairment for patients after esophagectomy (p < 0.001). Accordingly, esophagectomy patients were characterized by longer ventilation times (p < 0.0001), intensive care unit and total postoperative hospital stays (both p < 0.0001). In conclusion, the postoperative clinical course including respiratory impairment after Ivor Lewis esophagectomy is significantly worse than that after major pulmonary resection. A detailed investigation of the underlying causes is required to improve the outcome of esophagectomy.

Host-Derived Delta-Like Canonical Notch Ligand 1 as a Novel Diagnostic Biomarker for Bacterial Sepsis-Results From a Combinational Secondary Analysis

Background: Sepsis is a life-threatening syndrome, resulting from a dysbalanced host response to infection. However, especially the early, pro-inflammatory immune response in sepsis is similar to other inflammatory conditions without infectious cause, e.g., trauma or surgery. This aspect challenges the value of current biomarkers for diagnosis, as these are often broadly induced. We earlier identified Delta-like Protein 1 (DLL1), a canonical Notch ligand, to be released from monocytes upon bacterial stimulation. Considering the importance of monocytes in the pathophysiology of sepsis, we hypothesized that this mechanism might occur also in the clinical setting and DLL1 might serve as a biomarker of life-threatening bacterial infection.

Methods: We combined samples from three different studies, including subgroups of patients with sepsis (n = 80), surgical patients (n = 50), trauma patients (n = 36), as well as healthy controls (n = 50). We assessed plasma concentrations of DLL1 using ELISA. We performed Area-under-receiver-operator-curve (AUROC) analysis to evaluate the diagnostic performance of DLL1 compared to leucocytes, C-reactive protein (CRP), and procalcitonin (PCT).

Results: Plasma concentrations of DLL1 were strongly elevated already at sepsis onset and maintained elevated until day 7. In contrast, neither surgical patients nor patients after severe trauma presented with elevated levels, while conventional biomarkers of inflammation (e.g., leucocytes and CRP), responded. AUROC analysis revealed a cut-off of 30 ng/ml associated with the best diagnostic performance, yielding a superior accuracy of 91% for DLL1, compared to 75, 79, and 81% for CRP, leucocytes, and PCT.

Conclusion: DLL1 is a novel host-derived biomarker for the diagnosis of sepsis with a better performance compared to established ones, most likely due to its high robustness in non-infectious inflammatory responses.

Clinical Trial Registration:POCSEP-Trial DRKS00008090; MIRSI DRKS00005463; SPRINT DRKS00010991.

Elevated Presepsin Is Associated With Perioperative Major Adverse Cardiovascular and Cerebrovascular Complications in Elevated-Risk Patients Undergoing Noncardiac Surgery: The Leukocytes and Cardiovascular Perioperative Events Study

BACKGROUND

Perioperative major adverse cardiovascular and cerebrovascular events (MACCEs) are incompletely understood, and risk prediction is imprecise. Atherogenic leukocytes are crucial in cardiovascular events. However, it is unclear if surgical interventions affect leukocyte counts or activation status. Therefore, we investigated whether noncardiac surgery in patients with elevated cardiovascular risk is associated with changes in atherogenic leukocyte subsets and if these changes are related to perioperative MACCEs.

METHODS

We enrolled 40 patients in this single-center prospective observational cohort study. Total leukocytes and subpopulations, including classical, intermediate, and nonclassical monocytes and natural killer and regulatory T cells, were quantified before surgery, at 2 and 6 hours after skin incision, and at postoperative days 1 and 2 (POD1+2). The monocyte activation marker presepsin (sCD14-ST) was measured post hoc to determine differentiation of classical to nonclassical monocytes. We evaluated presepsin for prediction of the composite primary end point MACCE (cardiovascular death, myocardial infarction, myocardial ischemia, and stroke) at 30 days. Its additive value to risk assessment based on high-sensitive cardiac troponin T and N-terminal probrain natriuretic peptide (NT-proBNP) was analyzed.

RESULTS

We evaluated 38 patients, of whom 5 (13%) reached MACCE. In the entire cohort, classical monocytes continuously increased and peaked at POD1 (0.35 [0.23-0.43] cells per nanoliter blood [nL] vs 0.45 [0.31-0.66] cells·nL, preoperative [pre-OP] vs POD1, P = .002). Intermediate monocytes doubled by POD1 (0.017 [0.013-0.021] vs 0.036 [0.022-0.043] cells·nL, pre-OP versus POD1, P = .0003). Nonclassical monocytes decreased (0.022 [0.012-0.032] vs 0.012 [0.005-0.023] cells·nL, pre-OP vs 6 hours, P = .003). In our patient population, we did not detect changes in any of the other predefined leukocyte subsets investigated. In patients experiencing a MACCE, classical monocyte expansion was reduced (0.081 [-0.16 to 0.081] cells·nL vs 0.179 [0.081 to 0.292] cells·nL, MACCE versus non-MACCE, P = .016). Patients in the event group presented with elevated pre-OP presepsin (1528 [406-1897] pg·mL vs 123 [82.2-174] pg·mL, MACCE versus non-MACCE, P = .0001). Presepsin was associated with MACCE (area under the curve = 0.964, [0.846-0.998], P = .001). Presepsin above the calculated threshold >184 pg·mL was superior to high-sensitive cardiac troponin T for improvement of NT-proBNP-based risk prediction (28 [74%] vs 22 [58%] correctly classified patients, P = .014).

CONCLUSIONS

Noncardiac surgery was associated with an increase in atherogenic leukocyte subsets. In a post hoc analysis, elevated pre-OP presepsin was associated with MACCE and improved NT-proBNP-based risk assessment. After validation in an independent data set, a presepsin cutoff of 184 pg·mL might qualify to complement NT-proBNP-based risk prediction, thereby increasing the proportion of correctly identified high-risk patients.

Monocyte HLA-DR Assessment by a Novel Point-of-Care Device Is Feasible for Early Identification of ICU Patients With Complicated Courses-A Proof-of-Principle Study

Background: Critically ill patients, especially following trauma or extensive surgery, experience a systemic immune response, consisting of a pro-inflammatory as well as a counterbalancing anti-inflammatory response. Pro-inflammation is necessary for the initiation of homeostatic control and wound healing of the organism. However, when the counterbalancing mechanisms dominate, a condition of secondary immunodeficiency occurs, which renders the patient susceptible for opportunistic or secondary infections. However, the incidence of this condition is yet illusive.

Methods: For a period of 3 months (May to July 2017), 110 consecutive patients admitted to the surgical ICU of the Heidelberg University Hospital, a tertiary university hospital, were enrolled in the study. Monocyte HLA-DR (mHLA-DR), a long-known surrogate of monocyte function, was assessed quantitatively once on admission utilizing a novel point-of-care flow cytometer with single-use cartridges (Accelix system). Patients were followed up for further 28 days and data on ICU stay, antibiotic therapy, microbiological findings, and mechanical ventilation were recorded. Statistical analysis was performed to evaluate the incidence of immunosuppression—defined by different thresholds—as well as its consequence in terms of outcome and clinical course.

Results: Depending on the HLA-DR threshold applied for stratification (≤8,000/≤5,000/≤2,000 molecules/cell), a large group of patients (85.5/68.2/40.0%) already presented with a robust decrease of HLA-DR on admission, independent of the cause for critical illness. Analyzed for survival, neither threshold was able to stratify patients with a higher mortality. However, both thresholds of 2,000 and 5,000 were able to discriminate patients with longer ICU stay, ventilation time and duration of antibiotic therapy, as well as higher count of microbiological findings. Moreover, a mHLA-DR value ≤2,000 molecules/cell was associated with higher incidence of overall antibiotic therapy.

Conclusion: Single assessment of mHLA-DR using a novel point-of-care flow cytometer is able to stratify patients according to their risk of a complicated course. Therefore, this device overcomes the technical boundaries for measuring cellular biomarkers and paves the way for future studies involving personalized immunotherapy to patients with a high immunological risk profile independent of their background.

Trial Registration: German Clinical Trials Register; ID: DRKS00012348.

New approaches for the detection of invasive fungal diseases in patients following liver transplantation-results of an observational clinical pilot study

PURPOSE

Despite antifungal prophylaxis following liver transplantation (LTX), patients are at risk for the development of subsequent opportunistic infections, such as an invasive fungal disease (IFD). However, culture-based diagnostic procedures are associated with relevant weaknesses.

METHODS

Culture and next-generation sequencing (NGS)-based fungal findings as well as corresponding plasma levels of ß-D-glucan (BDG), galactomannan (GM), interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-2, -4, -6, -10, -17A and mid-regional proadrenomedullin (MR-proADM) were evaluated in 93 patients at 6 consecutive time points within 28 days following LTX.

RESULTS

A NGS-based diagnostic approach was shown to be suitable for the early identification of fungal pathogens in patients following LTX. Moreover, MR-proADM and IL-17A in plasma proved suitable for the identification of patients with an IFD.

CONCLUSION

Plasma measurements of MR-proADM and IL-17A as well as a NGS-based diagnostic approach were shown to be attractive methodologies to attenuate the weaknesses of routinely used culture-based diagnostic procedures for the determination of an IFD in patients following LTX. However, an additional confirmation within a larger multicenter trial needs to be recommended.

TRIAL REGISTRATION

German Clinical Trials Register: DRKS00005480 .

Gut microbiome patterns correlate with higher postoperative complication rates after pancreatic surgery

Background

Postoperative complications are of great relevance in daily clinical practice, and the gut microbiome might play an important role by preventing pathogens from crossing the intestinal barrier. The two aims of this prospective clinical pilot study were: (1) to examine changes in the gut microbiome following pancreatic surgery, and (2) to correlate these changes with the postoperative course of the patient.

Results

In total, 116 stool samples of 32 patients undergoing pancreatic surgery were analysed by 16S-rRNA gene next-generation sequencing. One sample per patient was collected preoperatively in order to determine the baseline gut microbiome without exposure to surgical stress and/or antibiotic use. At least two further samples were obtained within the first 10 days following the surgical procedure to observe longitudinal changes in the gut microbiome. Whenever complications occurred, further samples were examined.

Based on the structure of the gut microbiome, the samples could be allocated into three different microbial communities (A, B and C). Community B showed an increase in Akkermansia, Enterobacteriaceae and Bacteroidales as well as a decrease in Lachnospiraceae, Prevotella and Bacteroides. Patients showing a microbial composition resembling community B at least once during the observation period were found to have a significantly higher risk for developing postoperative complications (B vs. A, odds ratio = 4.96, p < 0.01**; B vs. C, odds ratio = 2.89, p = 0.019*).

Conclusions

The structure of the gut microbiome is associated with the development of postoperative complications.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1399-5) contains supplementary material, which is available to authorized users.

Acute fibrinolysis shutdown occurs early in septic shock and is associated with increased morbidity and mortality: results of an observational pilot study

BACKGROUND

Septic coagulopathy represents a very dynamic disease entity, tilting from initial hypercoagulability towards a subsequent hypocoagulable disease state, entitled overt disseminated intravascular coagulation. Acute fibrinolysis shutdown has recently been described to be a crucial component of initial hypercoagulability in critically ill patients, although the underlying pathomechanisms, the specific temporal kinetics and its outcome relevance in patients with sepsis remain to be determined.

METHODS

In total, 90 patients (30 with septic shock, 30 surgical controls and 30 healthy volunteers) were enrolled. Blood samples were collected at sepsis onset or prior and immediately after the surgical procedure as well as 3 h, 6 h, 12 h, 24 h, 48 h and 7 d later, whereas blood samples from healthy volunteers were collected once. Besides viscoelastic and aggregometric point-of-care testing (POCT), enzyme-linked immunosorbent and thrombin generation assays and liquid chromatography-mass spectrometry-based measurements were performed.

RESULTS

As assessed by viscoelastic POCT, fibrinolysis shutdown occurred early in sepsis. Significant increases in tissue plasminogen activator had no effect on thromboelastometrical lysis indices (LIs). Contrariwise, plasminogen activator inhibitor-1 was already significantly increased at sepsis onset, which was paralleled by significantly increased LIs in patients suffering from septic shock in comparison with both control groups. This effect persisted throughout the 7-day observation period and was most pronounced in severely ill as well as non-surviving septic patients. Thromboelastometrical LI, therefore, proved to be suitable for early diagnosis [e.g. LI 45 min: area under the curve (AUC) up to 0.933] as well as prognosis (e.g. LI 60 min: AUC up to 1.000) of septic shock.

CONCLUSIONS

Early inhibition of plasminogen activation leads to acute fibrinolysis shutdown with improved clot stability and is associated with increased morbidity and mortality in septic patients. Trial registration This study was approved by the local ethics committee (Ethics Committee of the Medical Faculty of Heidelberg; Trial-Code No. S247-2014/German Clinical Trials Register (DRKS)-ID: DRKS00008090; retrospectively registered: 07.05.2015). All study patients or their legal representatives signed written informed consent.

Sepsis Induces a Long-Lasting State of Trained Immunity in Bone Marrow Monocytes

Innate immune memory describes the functional reprogramming of innate immune cells after pathogen contact, leading to either a boosted (trained immunity) or a diminished (immune tolerance) response to a secondary stimulus. Immune tolerance or “sepsis-induced immunosuppression” is a typical hallmark of patients after sepsis survival, characterized by hypo-responsiveness of the host's immune system. This condition renders the host vulnerable for a persisting infection or the occurrence of secondary, often opportunistic infections, along with an increased mortality rate. The mechanisms involved in the maintenance of this long-lasting condition are not examined yet. Polymicrobial abdominal sepsis was induced in 12 week old male C57BL/6 mice by cecal ligation and puncture. Mice were euthanized 3 months after insult. Immune cell composition of the spleen and whole blood, as well as stem and progenitor cells of the bone marrow, were assessed by flow cytometry. Whole blood and bone marrow monocytes were stimulated with LPS and supernatant levels of TNF and IL-6 detected by ELISA. Furthermore, naïve bone marrow monocytes were analyzed for metabolic (Seahorse technology) and transcriptomic (RNA sequencing) changes. Flow cytometric analysis revealed an increase of inflammatory monocytes and regulatory T cells in the spleen, whereby immune composition of whole blood kept unchanged. Granulocyte-monocyte progenitor cells are increased in sepsis survivors. Systemic cytokine response was unchanged after LPS challenge. In contrast, cytokine response of post-septic naïve bone marrow monocytes was increased. Metabolic analysis revealed enhanced glycolytic activity, whereas mitochondrial indices were not affected. In addition, RNA sequencing analysis of global gene expression in monocytes revealed a sustained signature of 367 differentially expressed genes. We here demonstrate that sepsis via functional reprogramming of naïve bone marrow monocytes induces a cellular state of trained immunity, which might be counteracted depending on the compartmental localization of the cell. These findings shed new light on the complex aftermath of sepsis and open up a new pathophysiological framework in need for further research.

[New Sepsis-3 definition : Do we have to treat sepsis before we can diagnose it from now on?]

The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) have been available since the beginning of 2016. SEPSIS-3 completely replaces the old SIRS criteria in the definition of sepsis and defines sepsis from now on as "life-threatening organ dysfunction caused by a dysregulated host response to infection". However, it seems questionable whether in clinical practice the new definition is really superior to the old one. The most important question is the following: Is it helpful to have a definition that first recognizes a patient once organ dysfunction has occurred and the patient already needs intensive care?

Impact of human sepsis on CCCTC-binding factor associated monocyte transcriptional response of Major Histocompatibility Complex II components

Background

Antigen presentation on monocyte surface to T-cells by Major Histocompatibility Complex, Class II (MHC-II) molecules is fundamental for pathogen recognition and efficient host response. Accordingly, loss of Major Histocompatibility Complex, Class II, DR (HLA-DR) surface expression indicates impaired monocyte functionality in patients suffering from sepsis-induced immunosuppression. Besides the impact of Class II Major Histocompatibility Complex Transactivator (CIITA) on MHC-II gene expression, X box-like (XL) sequences have been proposed as further regulatory elements. These elements are bound by the DNA-binding protein CCCTC-Binding Factor (CTCF), a superordinate modulator of gene transcription. Here, we hypothesized a differential interaction of CTCF with the MHC-II locus contributing to an altered monocyte response in immunocompromised septic patients.

Methods

We collected blood from six patients diagnosed with sepsis and six healthy controls. Flow cytometric analysis was used to identify sepsis-induced immune suppression, while inflammatory cytokine levels in blood were determined via ELISA. Isolation of CD14⁺⁺ CD16^—monocytes was followed by (i) RNA extraction for gene expression analysis and (ii) chromatin immunoprecipitation to assess the distribution of CTCF and chromatin modifications in selected MHC-II regions.

Results

Compared to healthy controls, CD14⁺⁺ CD16^—monocytes from septic patients with immune suppression displayed an increased binding of CTCF within the MHC-II locus combined with decreased transcription of CIITA gene. In detail, enhanced CTCF enrichment was detected on the intergenic sequence XL9 separating two subregions coding for MHC-II genes. Depending on the relative localisation to XL9, gene expression of both regions was differentially affected in patients with sepsis.

Conclusion

Our experiments demonstrate for the first time that differential CTCF binding at XL9 is accompanied by uncoupled MHC-II expression as well as transcriptional and epigenetic alterations of the MHC-II regulator CIITA in septic patients. Overall, our findings indicate a sepsis-induced enhancer blockade mediated by variation of CTCF at the intergenic sequence XL9 in altered monocytes during immunosuppression.

Plasma sRAGE is independently associated with increased mortality in ARDS: a meta-analysis of individual patient data

PURPOSE

The soluble receptor for advanced glycation end-products (sRAGE) is a marker of lung epithelial injury and alveolar fluid clearance (AFC), with promising values for assessing prognosis and lung injury severity in acute respiratory distress syndrome (ARDS). Because AFC is impaired in most patients with ARDS and is associated with higher mortality, we hypothesized that baseline plasma sRAGE would predict mortality, independently of two key mediators of ventilator-induced lung injury.

METHODS

We conducted a meta-analysis of individual data from 746 patients enrolled in eight prospective randomized and observational studies in which plasma sRAGE was measured in ARDS articles published through March 2016. The primary outcome was 90-day mortality. Using multivariate and mediation analyses, we tested the association between baseline plasma sRAGE and mortality, independently of driving pressure and tidal volume.

RESULTS

Higher baseline plasma sRAGE [odds ratio (OR) for each one-log increment, 1.18; 95% confidence interval (CI) 1.01-1.38; P = 0.04], driving pressure (OR for each one-point increment, 1.04; 95% CI 1.02-1.07; P = 0.002), and tidal volume (OR for each one-log increment, 1.98; 95% CI 1.07-3.64; P = 0.03) were independently associated with higher 90-day mortality in multivariate analysis. Baseline plasma sRAGE mediated a small fraction of the effect of higher ΔP on mortality but not that of higher VT.

CONCLUSIONS

Higher baseline plasma sRAGE was associated with higher 90-day mortality in patients with ARDS, independently of driving pressure and tidal volume, thus reinforcing the likely contribution of alveolar epithelial injury as an important prognostic factor in ARDS. Registration: PROSPERO (ID: CRD42018100241).