Interleukin-6 Levels Act as a Diagnostic Marker for Infection and a Prognostic Marker in Patients with Organ Dysfunction in Intensive Care Units

IL-6 Baseline Values and Dynamic Changes in Predicting Sepsis Mortality: A Systematic Review and Meta-Analysis

Sepsis, a life-threatening condition arising from a dysregulated immune response to infection, is a significant health burden globally. Interleukin-6 (IL-6), an inflammatory cytokine produced by immune cells as a response to infection and tissue damage, plays a key role in the pathogenesis of sepsis. This systematic review and meta-analysis aimed to investigate the association of the baseline plasma levels of IL-6, and the dynamic change in these levels over a timespan of 96 h, with short-term mortality. A systematic literature search was conducted across multiple databases. Studies were included if they assessed the independent prognostic value of IL-6 in adult sepsis patients, used well-defined sepsis criteria, and reported at least one IL-6 measurement. Pooled effect estimates for the association between IL-6 and 28-30-day mortality were determined using logistic regression and AUROC analysis. Thirty-one studies, encompassing 4566 patients, were included. While baseline IL-6 levels and 96 h IL-6 clearance were not significantly associated with mortality risk (pooled OR 1.001, 95% CI 0.999-1.003 and 1.019, 95% CI 0.925-1.112, respectively), AUROC analysis indicated moderate-to-good discriminatory power for both baseline (0.701, 95% CI 0.660-0.742) and 96 h IL-6 clearance (0.828, 95% CI 0.736-0.919) in predicting 28-day mortality. While not a strong independent predictor, IL-6 demonstrates some discriminatory ability, suggesting its potential value in conjunction with other biomarkers.

Efficiency of IL-6 in Early Prognosis and Follow-Up in Critically Ill Patients with Septic Shock

Background/Objectives: The aim of this study was to investigate the response of interleukin-6 (IL-6) during the first few hours of a patient's stay in the Intensive Care Unit (ICU) in a sample of critically ill patients with septic shock, compared to healthy subjects as controls. Additionally, the study examined the association of IL-6 with morbidity and mortality in these patients, as well as its relationship with biomarkers such as lactic acid, C-reactive protein (CRP) and procalcitonin (PCT). Methods: This was a prospective analytical study involving 28 critically ill patients with septic shock, monitored from ICU admission through to their first three days of stay. Demographic data, comorbidities and clinical information, including IL-6 and severity scores, were recorded. Results: IL-6 levels were significantly higher in patients with septic shock compared to healthy subjects (p < 0.001) upon admission. IL-6 levels decreased by the third day of ICU stay (p < 0.005). An association between IL-6 and mortality was observed (areas under the curve 0.826, confidence interval (CI) 95% 0.659-0.994, p < 0.008). Significant correlations between IL-6 and lactic acid (p < 0.009 and p < 0.018) and partial thromboplastin time (p < 0.004 and p < 0.007) were found on the first and third days, respectively. IL-6 was also the correlated with an anion gap at admission to the ICU (p < 0.009). Conclusions: In conclusion, this study suggests that IL-6 could be a valuable marker for early sepsis follow-up in ICU patients, particularly during the first 72 h of hospitalization, providing important prognostic information in patients with septic shock.

A Prospective Study of the Association of IL6 with the Critical Unit and Their Effect on in-Hospital Mortality in Critically Ill Patients

Purpose

We previously proposed a new concept, the "critical unit", which covers the structural integrity and function of mitochondria and endothelium. Injury of the critical unit plays a key role in the development of critical illnesses. High levels of inflammation may lead to abnormalities of the critical unit, which is an important mechanism for critical illnesses, and both inflammation and critical unit dysfunction may affect patient prognosis. Here we evaluated the correlation between interleukin-6 (IL6) and the critical unit biomarkers in critically ill patients and the impact of both on prognosis.

Patients and Methods

This study included adult patients admitted to the intensive care unit for various reasons from January 1st to May 31st, 2023. Baseline characteristics, intensive care unit parameters, and laboratory test and outcome data were obtained from the electronic medical records system. Critical unit parameters were measured using polymerase chain reaction and enzyme-linked immunosorbent assay methods. Correlations were examined between IL6, critical unit parameters, and various outcomes.

Results

In critically ill patients, IL6 was closely associated with all the critical unit biomarkers (activated partial thromboplastin time, sphingosine 1-phosphate, mitochondrial DNA, mitochondrial fission 1, and Parkin) and the prognoses of patients. A nomogram was constructed using the critical unit biomarkers to predict the in-hospital mortality of critically ill patients. The area under the curve for the mortality prediction model was 0.708. In sensitivity analyses, the predictive effect was better in the non-surgery and tumor groups compared with the surgery and non-tumor groups, with area under the curve values of 0.885 and 0.891, respectively.

Conclusion

Our study innovatively integrated mitochondrial and endothelial markers in the critical unit to comprehensively evaluate patient prognosis, which may be a trend in the future assessment of critically ill patients. There are few such studies, and ours may promote the progress of related research.

Diagnostic Potential of Serum Interleukin-6 in Predicting Bacteremia in Adult Patients with Sepsis: A Prospective Observational Study

Background

This study aimed to assess the potential of serum interleukin-6 (IL-6) as a diagnostic marker in predicting bacteremia and to determine its association with severity and outcome among sepsis patients.

Materials and methods

A prospective observational study was conducted, comprising a cohort of 118 patients admitted to the ICU with suspected sepsis from January 2019 to April 2020.

Results

Among the 108 patients analyzed, 60 (55.6%) were bacteremic and 48 (44.4%) were nonbacteremic. Of 60 patients with bacteremia, 13 (21.6%) had sepsis and 47 (78.3%) had septic shock. In predicting bacteremia, the area under the curve (AUC) for IL-6 was 0.512 [95% CI, 0.400-0.623]. The AUC for IL-6 in differentiating sepsis from septic shock was 0.724 [95% CI, 0.625-0.823]. The sensitivity and specificity for predicting bacteremia for IL-6 were 66% and 67%, respectively (p < 0.001). Multivariate analysis revealed that C-reactive protein (CRP) (p = 0.04) and APACHE II score (p = 0.025) were significant predictors of bacteremia, whereas lactate (p = 0.04), and APACHE II score (p < 0.001) were significant predictors of sepsis severity. Patients with elevated levels of procalcitonin PCT (p = 0.024), APACHE II (p = 0.003), and SOFA (p = 0.002) scores had significantly higher mortality rates.

Conclusion

C-reactive protein and APACHE II score, lactate and APACHE II score, and PCT, SOFA, and APACHE II scores performed better in predicting bacteremia, sepsis severity, and clinical outcome, respectively compared with IL-6.

How to cite this article

Reddy PRV, Cherukuri M, Eshwara VK, Kudru CU, Prabhu RVK. Diagnostic Potential of Serum Interleukin-6 in Predicting Bacteremia in Adult Patients with Sepsis: A Prospective Observational Study. Indian J Crit Care Med 2024;28(7):637-644.

INTERPLAY BETWEEN BRAIN OXYGENATION AND THE DEVELOPMENT OF HYPOTHERMIA IN ENDOTOXIC SHOCK

ABSTRACT

There is evidence to suggest that the hypothermia observed in the most severe cases of systemic inflammation or sepsis is a regulated response with potential adaptive value, but the mechanisms involved are poorly understood. Here, we investigated the interplay between brain oxygenation (assessed by tissue P o2 ) and the development of hypothermia in unanesthetized rats challenged with a hypotension-inducing dose of bacterial LPS (1 mg/kg i.v.). At an ambient temperature of 22°C, oxygen consumption (V̇O 2 ) began to fall only a few minutes after the LPS injection, and this suppression in metabolic rate preceded the decrease in core temperature. No reduction in brain P o2 was observed prior to the development of the hypometabolic, hypothermic response, ruling out the possibility that brain hypoxia served as a trigger for hypothermia in this model. Brain P o2 was even increased. Such an improvement in brain oxygenation could reflect either an increased O 2 delivery or a decreased O 2 consumption. The former explanation seems unlikely because blood flow (cardiac output) was being progressively decreased during the recording period. On the other hand, the decrease in V̇O 2 usually preceded the rise in P o2 , and an inverse correlation between V̇O 2 and brain P o2 was consistently observed. These findings do not support the existence of a closed-loop feedback relationship between brain oxygenation and hypothermia in systemic inflammation. The data are consistent with a feedforward mechanism in which hypothermia is triggered (possibly by cryogenic inflammatory mediators) in anticipation of changes in brain oxygenation to prevent the development of tissue hypoxia.

Serum Mrp 8/14 as a Potential Biomarker for Predicting the Occurrence of Acute Respiratory Distress Syndrome Induced by Sepsis: A Retrospective Controlled Study

Background

To date, there are no studies regarding the Mrp 8/14 in predicting the occurrence of acute respiratory distress syndrome (ARDS) induced by sepsis. Thus, the objective of this study was to investigate the expression of Myeloid-related proteins 8 and 14 (Mrp 8/14) and its role in ARDS induced by sepsis.

Methods

A total of 168 septic patients were enrolled in the observational study. The baseline information and clinical outcomes were obtained retrospectively. Serum Mrp 8/14 level was determined by enzyme linked immunosorbent assay (ELISA). The patients were categorized into sepsis and ARDS group based on whether they developed ARDS during the intensive care unit (ICU) hospitalization.

Results

There was significant difference in the level of Mrp 8/14 between the sepsis group and ARDS groups (P < 0.05). Mrp 8/14 correlated positively with procalcitonin (PCT), interleukin-6 (IL-6), acute physiology and chronic health evaluation II (APACHE II) score, sequential organ failure assessment (SOFA) score on day 1, mechanical ventilation time, length of ICU stay and hospitalization expenses in ICU (all P < 0.05). Logistic regression analysis showed Mrp 8/14 was the independent factor for forecasting the occurrence of sepsis- induced ARDS (P < 0.05). The areas under receiver operating characteristic curves for Mrp 8/14 were higher than that of PCT, APACHE II score and SOFA score on day 1 (P < 0.05).

Conclusion

The serum Mrp 8/14 level at admission may be a potential marker for predicting the occurrence of ARDS induced by sepsis. Early detection of serum Mrp 8/14 could help clinicians to identify and evaluate the severity of ARDS induced by sepsis.

Thrombocytopenia Independently Leads to Changes in Monocyte Immune Function

BACKGROUND

While platelets have well-studied hemostatic functions, platelets are immune cells that circulate at the interface between the vascular wall and white blood cells. The physiological implications of these constant transient interactions are poorly understood. Activated platelets induce and amplify immune responses, but platelets may also maintain immune homeostasis in healthy conditions, including maintaining vascular integrity and T helper cell differentiation, meaning that platelets are central to both immune responses and immune quiescence. Clinical data have shown an association between low platelet counts (thrombocytopenia) and immune dysfunction in patients with sepsis and extracorporeal membrane oxygenation, further implicating platelets as more holistic immune regulators, but studies of platelet immune functions in nondisease contexts have had limited study.

METHODS

We used in vivo models of thrombocytopenia and in vitro models of platelet and monocyte interactions, as well as RNA-seq and ATAC-seq (assay for transposase-accessible chromatin with sequencing), to mechanistically determine how resting platelet and monocyte interactions immune program monocytes.

RESULTS

Circulating platelets and monocytes interact in a CD47-dependent manner to regulate monocyte metabolism, histone methylation, and gene expression. Resting platelet-monocyte interactions limit TLR (toll-like receptor) signaling responses in healthy conditions in an innate immune training-like manner. In both human patients with sepsis and mouse sepsis models, thrombocytopenia exacerbated monocyte immune dysfunction, including increased cytokine production.

CONCLUSIONS

Thrombocytopenia immune programs monocytes in a manner that may lead to immune dysfunction in the context of sepsis. This is the first demonstration that sterile, endogenous cell interactions between resting platelets and monocytes regulate monocyte metabolism and pathogen responses, demonstrating platelets to be immune rheostats in both health and disease.

Diagnostic and Prognostic Value of Pentraxin 3, Interleukin-6, CRP, and Procalcitonin Levels in Patients with Sepsis and Septic Shock

INTRODUCTION AND PURPOSE

In this prospective study, we aim to evaluate the effects of antibiotherapy on pentraxin-3 (PTX3), C-reactive protein (CRP), and interleukin-6 (IL-6) levels in patients with sepsis and septic shock.

MATERIALS AND METHODS

In our study, CRP, procalcitonin, IL-6, and PTX3 levels at initial and 48 hours of the antibiotherapy of patients who were admitted to the pediatric intensive care unit (PICU) with the diagnosis of sepsis and septic shock between June 2020 and March 2021 were compared. Patients were compared with the age-appropriate case-control group formed from the patients who received pre-operative routines to investigate the diagnostic value.

RESULTS

CRP, IL-6, and PTX3 levels of the patients were significantly higher compared to controls (P < 0.05). After the 48th hour of treatment compared to initial CRP, lactate and PCT levels were significantly lower (P < 0.05). The IL-6 and PCT levels were significantly higher in patients with mortality than in surviving patients. Surviving patients showed a significant decrease in CRP level at the 48th hour. IL-6 levels of patients with septic shock were significantly higher than those with sepsis (P = 0.010; P < 0.05). In the diagnosis of septic shock, the area under curve was 0.785 for IL-6 and the standard deviation was 0.09 (P = 0.002, cut-off value, >32 pg/mL, 88.9% sensitivity, 65.6% specifity).

CONCLUSION

The results of this study indicated that IL-6 level is an appropriate biomarker with high specificity in the diagnosis of sepsis and septic shock and in evaluating the response to treatment and determining the prognosis.

Obesity Alters cytokine signaling and gut microbiome in septic mice

Sepsis is a leading cause of mortality. Plasma cytokine levels may identify those at increased risk of mortality from sepsis. Our aim was to understand how obesity alters cytokine levels during early sepsis and its correlation with survival. Six-week-old C57BL/6 male mice were randomized to control (non-obese) or high fat diet (obese) for 5-7 weeks. Sepsis was induced by cecal ligation and perforation (CLP). Cytokine levels were measured from cheek bleeds 8 h after CLP, and mice were monitored for survival. Other cohorts were sacrificed 1 h after CLP for plasma and tissue. Septic obese mice had higher survival. At 8 h after sepsis, obese mice had higher adiponectin, leptin, and resistin but lower TNFα and IL-6 compared to non-obese mice. When stratified by 24-h survival, adipokines were not significantly different in obese and non-obese mice. TNFα and IL-6 were higher in non-obese, compared to obese, mice that died within 24 h of sepsis. Diet and to sepsis significantly impacted the cecal microbiome. IL-6 is a prognostic biomarker during early sepsis in non-obese and obese mice. A plausible mechanism for the survival difference in non-obese and obese mice may be the difference in gut microbiome and its evolution during sepsis.

Shock drives a STAT3 and JunB-mediated coordinated transcriptional and DNA methylation response in the endothelium

Endothelial dysfunction is a crucial factor in promoting organ failure during septic shock. However, the underlying mechanisms are unknown. Here, we show that kidney injury after lipopolysaccharide (LPS) insult leads to strong endothelial transcriptional and epigenetic responses. Furthermore, SOCS3 loss leads to an aggravation of the responses, demonstrating a causal role for the STAT3-SOCS3 signaling axis in the acute endothelial response to LPS. Experiments in cultured endothelial cells demonstrate that IL-6 mediates this response. Furthermore, bioinformatics analysis of in vivo and in vitro transcriptomics and epigenetics suggests a role for STAT, AP1 and interferon regulatory family (IRF) transcription factors. Knockdown of STAT3 or the AP1 member JunB partially prevents the changes in gene expression, demonstrating a role for these transcription factors. In conclusion, endothelial cells respond with a coordinated response that depends on overactivated IL-6 signaling via STAT3, JunB and possibly other transcription factors. Our findings provide evidence for a critical role of IL-6 signaling in regulating shock-induced epigenetic changes and sustained endothelial activation, offering a new therapeutic target to limit vascular dysfunction.

Comparison between presepsin, procalcitonin, and CRP as biomarkers to diagnose sepsis in critically ill patients

BACKGROUND AND AIMS

Mortality associated with sepsis continues to remain high. Early diagnosis and aggressive management may improve outcomes. Biomarkers may help in early diagnosis, but the search for an ideal biomarker continues. Presepsin has been introduced as a new biomarker, however, it still needs validation before its use becomes routine. In this study, we aimed to compare the efficacy of various biomarkers in patients with suspected sepsis.

MATERIAL AND METHODS

A retrospective analysis of 100 patients with suspected infection, admitted in the medical intensive care unit (ICU) was conducted. Diagnosis of sepsis was made on the basis of the current surviving sepsis guidelines criteria.

RESULTS

Out of 100 patients, 70 were diagnosed to have sepsis, and overall ICU mortality was 22%. Overall, C-reactive protein (CRP) was positive in 98, procalcitonin in 75, and presepsin in 64 patients. For diagnosis of sepsis the sensitivity, specificity, and AUC, respectively, for CRP was 98.6%, 3.3%, and 0.725. For procalcitonin (>0.5 ng/ml) it was 87.1%, 53.3%, and 0.776, and for procalcitonin (>1 ng/ml) 70%, 70%, and 0.816, respectively. For presepsin sensitivity, specificity, and AUC, respectively, for diagnosis of sepsis was 77.1%, 66.7%, and 0.734. For ICU mortality, sensitivity and specificity for CRP was 95.5% and 1.3%, for procalcitonin (>0.5) 72.7% and 24.4.%, for procalcitonin (>1) 59.1% and 42.3%, and for presepsin 61.5% and 27.3%, respectively.

CONCLUSION

Inflammatory markers may be raised in a large proportion of ICU patients, even in those without sepsis. Procalcitnonin and presepsin had similar efficacy in diagnosing sepsis. However, none of the three biomarkers studied were accurate in predicting ICU mortality.

Thrombocytopenia Independently Leads to Monocyte Immune Dysfunction

In addition to their well-studied hemostatic functions, platelets are immune cells. Platelets circulate at the interface between the vascular wall and leukocytes, and transient platelet-leukocyte complexes are found in both healthy and disease states, positioning platelets to provide physiologic cues of vascular health and injury. Roles for activated platelets in inducing and amplifying immune responses have received an increasing amount of research attention, but our past studies also showed that normal platelet counts are needed in healthy conditions to maintain immune homeostasis. We have now found that thrombocytopenia (a low platelet count) leads to monocyte dysfunction, independent of the cause of thrombocytopenia, in a manner that is dependent on direct platelet-monocyte CD47 interactions that regulate monocyte immunometabolism and gene expression. Compared to monocytes from mice with normal platelet counts, monocytes from thrombocytopenic mice had increased toll-like receptor (TLR) responses, including increased IL-6 production. Furthermore, ex vivo co-incubation of resting platelets with platelet naïve bone marrow monocytes, induced monocyte metabolic programming and durable changes in TLR agonist responses. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-Seq) on monocytes from thrombocytopenic mice showed persistently open chromatin at LPS response genes and resting platelet interactions with monocytes induced histone methylation in a CD47 dependent manner. Using mouse models of thrombocytopenia and sepsis, normal platelet numbers were needed to limit monocyte immune dysregulation and IL6 expression in monocytes from human patients with sepsis also inversely correlated with patient platelet counts. Our studies demonstrate that in healthy conditions, resting platelets maintain monocyte immune tolerance by regulating monocyte immunometabolic processes that lead to epigenetic changes in TLR-related genes. This is also the first demonstration of sterile cell interactions that regulate of innate immune-metabolism and monocyte pathogen responses.

Acute organ injury and long-term sequelae of severe pneumococcal infections

Streptococcus pneumoniae (Spn) is a major public health problem, as it is a main cause of otitis media, community-acquired pneumonia, bacteremia, sepsis, and meningitis. Acute episodes of pneumococcal disease have been demonstrated to cause organ damage with lingering negative consequences. Cytotoxic products released by the bacterium, biomechanical and physiological stress resulting from infection, and the corresponding inflammatory response together contribute to organ damage accrued during infection. The collective result of this damage can be acutely life-threatening, but among survivors, it also contributes to the long-lasting sequelae of pneumococcal disease. These include the development of new morbidities or exacerbation of pre-existing conditions such as COPD, heart disease, and neurological impairments. Currently, pneumonia is ranked as the 9^th leading cause of death, but this estimate only considers short-term mortality and likely underestimates the true long-term impact of disease. Herein, we review the data that indicates damage incurred during acute pneumococcal infection can result in long-term sequelae which reduces quality of life and life expectancy among pneumococcal disease survivors.

Predictive value of serum interleukin-6 to determine surgical drainage of deep neck space infection in adults

PURPOSE

The aim of this study was to determine whether interleukin-6 (IL-6) could be used as a predictor for surgical drainage in deep neck space infection (DNSI).

METHODS

A retrospective study was conducted to analyze 69 adult patients newly diagnosed as DNSI from January 2017 to December 2021 at a single center. The patients were treated with either surgical drainage or not. The following clinical data including age, gender, maximum diameter of abscess (MDA), laboratory data, therapeutic modalities, comorbidities, duration of hospitalization and complications were collected and evaluated.

RESULTS

Patients in drained group had significantly elevated MDA, IL-6, procalcitonin, C-reactive protein and neutrophil to lymphocyte ratio compared to patients in non-drained group (all P < 0.01). Significant predictors for surgical drainage were IL-6 and MDA as independent factors, with the optimum cutoff values of 52.5 pg/mL and 14.4 mm, respectively. Moreover, the IL-6 had a wider area under the curve than MDA for prediction of surgical drainage in DNSI.

CONCLUSIONS

IL-6 as a promising predictor of the need for surgical drainage can be effectively used for routine assessment in the early stage of DNSI to determine the optimal treatments.

Insights into the Prognostic Role of Serum Interleukin-6 and Hematobiochemical Alterations in Cattle during Recent Outbreaks of Lumpy Skin Disease in Lodhran District, Pakistan

Lumpy skin disease (LSD) is a highly infectious disease of cattle caused by a virus of the Poxviridae family, genus Capripoxvirus. The present study was designed to determine the prognostic ability of serum IL-6 in LSD using a binary logistic regression model at baseline sampling. A 17-day cohort study was conducted on a recent outbreak of LSD among cattle in the Lodhran District of Punjab, Pakistan. Infected cattle were divided into two categories based on their clinical status on day 17 as recovered (n = 33) or unrecovered (n = 17). Nodular lesions and scab specimens (n = 50) were used for the isolation of the lumpy skin disease virus and were confirmed by PCR. In recovered animals, hematological results showed marked leukocytosis, eosinophilia, lymphocytosis, neutrophilia, and monocytopenia. However, marked erythrocytosis, leukopenia, and thrombocytopenia were observed in the unrecovered animals at the final sampling point of the study. Serum levels of total protein, albumin, and glucose were significantly higher in the recovered animals. Meanwhile, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatinine phosphokinase, total bilirubin, and direct bilirubin were found considerably higher in the unrecovered group. Receiver-operating characteristic curve analysis for serum IL-6 at baseline predicts the extended clinical conditions at the cut-off value of 85.16 pg/mL (55% specificity, 94% sensitivity, area under the curve 0.8039, respectively). In conclusion, the disease-induced hematological and biochemical alterations were significantly ameliorated in the recovered animals. In addition, the study revealed that serum IL-6 can be used as a valid marker for predicting the clinical worsening of LSD in cattle.

28-day sepsis mortality prediction model from combined serial interleukin-6, lactate, and procalcitonin measurements: a retrospective cohort study

Sepsis is a global medical issue owing to its unacceptably high mortality rate. Therefore, an effective approach to predicting patient outcomes is critically needed. We aimed to search for a novel 28-day sepsis mortality prediction model based on serial interleukin-6 (IL-6), lactate (LAC), and procalcitonin (PCT) measurements. We enrolled 367 septic patients based on Sepsis-3 (Third International Consensus Definitions for Sepsis and Septic Shock). Serum IL-6, LAC, and PCT levels were measured serially. Results collected within 24 and 48-72 h of admission were marked as D1 and D3 (e.g., IL-6D1/D3), respectively; the IL-6, LAC, and PCT clearance (IL-6c, LACc, PCTc) at D3 were calculated. Data were split into training and validation cohorts (7:3). Logistic regression analyses were used to select variables to develop models and choose the best one according to the Akaike information criterion (AIC). Receiver operating characteristic curves (ROC), calibration plots, and decision curve analysis (DCA) were used to test model performance. A nomogram was used to validate the model. There were 314 (85.56%) survivors and 53 (14.44%) non-survivors. Logistic regression analyses showed that IL-6D1, IL-6D3, PCTD1, PCTD3, and LACcD3 could be used to develop the best prediction model. The areas under the curves (AUC) of the training (0.849, 95% CI: 0.787-0.911) and validation cohorts (0.828, 95% CI: 0.727-0.929), calibration plot, and the DCA showed that the model performed well. Thus, the predictive value of the risk nomogram was verified. Combining IL-6D1, IL-6D3, PCTD1, PCTD3, and LACcD3 may create an accurate prediction model for 28-day sepsis mortality. Multiple-center research with a larger quantity of data is necessary to determine its clinical utility.

Discrepancy of C-Reactive Protein, Procalcitonin and Interleukin-6 at Hospitalization: Infection in Patients with Normal C-Reactive Protein, Procalcitonin and High Interleukin-6 Values

C-reactive protein (CRP) or procalcitonin (PCT) alone has limitations in the early detection of infection or inflammation due to shortcomings in specificity and varied cut-off values. Recently, interleukin (IL)-6 has been assessed, but it is not known to what extent the three values are homogeneous in reality. This retrospective study was conducted with two large datasets (discrepancy set with results within 24 h of admission [7149 patients] and follow-up set until 2 weeks of hospital stay [5261 tests]) consisting of simultaneous examinations of CRP, PCT, and IL-6 between January 2015 and August 2021. The specific discrepant group (n = 102, 1.4%) with normal CRP (<10 mg/L) and PCT (<0.1 ng/mL) and high IL-6 (≥100 pg/mL) values was extracted from the discrepancy set. Dimensionality reduction and visualization were performed using Python. The three markers were not clearly clustered after t-distributed stochastic neighbor embedding. Pearson’s correlation coefficients between two markers were substantially low (0.23−0.55). Among the high normalized IL-6 levels (≥0.5) (n = 349), 17.8% and 38.7% of CRP and PCT levels were very low (≤0.01). 9.2% and 13.4% of normal CRP (n = 1522) had high PCT (≥0.5 ng/mL) and IL-6 (≥100 pg/mL) values, respectively. Infection and bacteremia among 102 patients occurred in 36 (35.3%) and 9 (8.8%) patients, respectively. In patients with bacteremia, IL-6 was the first to increase, followed by PCT and CRP. Our study revealed that CRP, PCT, and IL-6 levels were considerably discrepant, which could be misinterpreted if only CRP tests are performed.

Diagnostic and Prognostic Value of Interleukin-6 in Emergency Department Sepsis Patients

Purpose

The objective of this study was to explore the diagnostic and prognostic value of interleukin-6 (IL-6) in sepsis patients presenting to the emergency department.

Patients and Methods

A total of 128 patients who visited the emergency department of West Hospital of Beijing Chaoyang Hospital, affiliated to Capital Medical University, from November 2021 to February 2022 were subjected to this study. According to Sepsis-3.0 diagnostic criteria for sepsis, patients were divided into non-sepsis group (65 cases) and sepsis group (63 cases). Demographic data and clinical characteristics of the two patient groups were compared. Serum levels of biomarkers including IL-6, blood urea nitrogen (BUN), and lactic acid (Lac) were compared with Sequential Organ Failure Assessment (SOFA) and Glasgow Coma Scale (GCS) scores. Logistic regression was used to analyze independent risk factors and Receiver Operating Characteristic Curve (ROC) method was used to analyze the Area Under the Curve (AUC) to determine the diagnostic and prognostic value of markers.

Results

Compared with non-sepsis patients, levels of IL-6, PCT, CRP and BUN were significantly higher in sepsis patients (10.84 (4.41–27.01): 92.22 (21.53–201.12), 0.03 (0.01–0.1):0.49 (0.08–3.1), 8.3 (0.5–31.8):39.8(10.3–98.6), 7.01 (4.90–11.74):13.03 (6.93–25.99), all p = 0.001). IL-6, BUN and mean arterial pressure (MAP) were independent risk factors for sepsis diagnosis. AUC values of IL-6, BUN, MAP and IL-6+BUN+MAP were 0.764, 0.696, 0.685, and 0.848, respectively. Lactate, age and SOFA score were independent risk factors for 28-day mortality in sepsis patients. The AUC of Lac, age, SOFA score and Lac+age+SOFA score to predict 28-day death in sepsis patients was 0.679, 0.626, 0.747, and 0.819, respectively.

Conclusion

IL-6 is an independent predictor of sepsis diagnosis, and the combination of blood BUN and MAP has superior diagnostic performance. Lac, age, and SOFA score could effectively predict clinical outcomes in patients with sepsis.

A Larger Membrane Area Increases Cytokine Removal in Polymethyl Methacrylate Hemofilters

Blood purification is performed to control cytokines in critically ill patients. The relationship between the clearance (CL) and the membrane area during adsorption is not clear. We hypothesized that the CL increases with the hydrophobic area when hydrophobic binding contributes to cytokine adsorption. We investigated the relationship between the hemofilter membrane area and the CL of the high mobility group box 1 protein (HMGB-1) and interleukin-6 (IL-6). We performed experimental hemofiltration in vitro using polymethyl methacrylate membranes CH-1.8W (1.8 m²) and CH-1.0N (1.0 m²), as well as polysulfone membrane NV-18X (1.8 m²). After adding 100 mg of HMGB1 or 10 μg of IL-6 into the test solution, experimental hemofiltration was conducted for 360 min in a closed-loop circulation system, and the same amount of HMGB1 and IL-6 was added after 180 min. With CH-1.8W and CH-1.0N, both HMGB-1 and IL-6 showed a rapid concentration decrease of more than 70% at 180 min and 360 min after the re-addition. At 15 min, the CL of HMGB-1 was CH-1.8W: 28.4 and CH-1.0N: 19.8, and that of IL-6 was CH-1.8W: 41.1 and CH-1.0N: 25.4. CH-1.8W and CH-1.0N removed HMGB1 and IL-6 by adsorption and CH-1.8W was superior in CL, which increased with a greater membrane area.

SOCS3 limits TNF and endotoxin-induced endothelial dysfunction by blocking a required autocrine interleukin 6 signal in human endothelial cells

Increased circulating levels of soluble interleukin (IL)-6 receptor α (sIL-6Rα) are commonly observed during inflammatory responses, allowing for IL-6 signaling in cells that express the ubiquitous receptor subunit gp130 but not IL-6Rα, such as endothelial cells. Activation of Toll-like receptor (TLR)-4 or the tumor necrosis factor (TNF) receptor leads to NF-κB-dependent increases in endothelial IL-6 expression. Thus, we hypothesize that danger signals may induce autocrine IL-6 signaling within the endothelium via sIL-6Rα-mediated trans-signaling. In support of this hypothesis, we recently demonstrated that conditional deletion in the endothelium of the IL-6 signaling inhibitor SOCS3 leads to rapid mortality in mice challenged with the TLR-4 agonist endotoxin through increases in vascular leakage, thrombosis, leukocyte adhesion, and a type I-like interferon response. Here, we sought to directly test a role for sIL-6Rα in LPS-treated human umbilical vein and dermal blood microvascular endothelial cells. We show that co-treatment with sIL-6Rα dramatically increases the loss of barrier function and the expression of COX2 and tissue factor mRNA levels induced by LPS. This co-treatment led to a strong activation of STAT1 and STAT3 while not affecting LPS-induced activation of p38 and NF-κB signaling. Similar results were obtained when sIL-6Rα was added to a TNF challenge. JAK inhibition by pretreatment with ruxolitinib or by SOCS3 overexpression blunted LPS and sIL-6R synergistic effects, while SOCS3 knockdown further increased the response. Together, these findings demonstrate that IL-6 signaling downstream of NF-kB activation leads to a strong endothelial activation and may explain the acute endotheliopathy observed during critical illness.

Fournier’s gangrene: the current state of the problem and our treatment experience

The OBJECTIVE of the study was to analyze the results of treatment of patients with lightning scrotal gangrene (Fournier’s gangrene).METHODS AND MATERIAL. The work is based on the analysis of the results of treatment of 31 patients with Fournier’s gangrene aged 32 to 82 years. In 19 (61.3 %) patients, the most probable nosological causes of Fournier’s gangrene were diseases of the anorectal zone, in 10 – pathology of the urogenital sphere. In 2 patients, Fournier’s gangrene developed as a result of a closed injury (1) and a gunshot wound (1) of the perineum and scrotum. A limited (slowly progressing) form of the disease was observed in 18 (58.1 %) patients, a common form with a lightning (9) and rapidly progressing (4) course – in 13 (41.9 %). 6 (19.3 %) patients suffered from diabetes mellitus of varying severity. In all patients, the clinical manifestations of the disease and laboratory parameters were characterized by the phenomena of generalized surgical infection with signs of systemic inflammatory response syndrome and endotoxicosis. In 93.5 % of patients, causative microflora was represented by various associations of both facultative-anaerobic and obligateaerobic gram-negative and obligate-facultative anaerobic gram-positive microorganisms. The growth of anaerobic gramnegative non-clostridial flora was also obtained.RESULTS. Out of 31 patients, 6 (19.3 %) patients died who had a common form of FG with a lightning and rapidly progressing clinical course in the format of systemic inflammatory response syndrome and systemic endotoxicosis with an outcome in organ-system dysfunction. The causes of death were: septic shock (in 1), progressive systemic endotoxicosis (sepsis) with the outcome of multiple organ failure (in 3) and pulmonary embolism (in 2).CONCLUSION. Multidisciplinary approach to solving organizational and therapeutic and tactical tasks with the participation of doctors of related specialties, active surgical tactics in the format of «aggressive surgery», providing for the widest possible excision of necrotic and non-viable tissues, performed in combination with programmed (stage-by-stage) sanitation necrectomy, pathogenetically justified correction of violations of the homeostasis system, rational antibacterial therapy, a comprehensive system of local wound treatment and plastic replacement of lost integumentary tissues are priority ways to optimize the results of treatment of patients with Fournier’s gangrene.

IL-6 and IL-10 Are Associated With Gram-Negative and Gram-Positive Bacteria Infection in Lymphoma

To investigate the Th1/Th2 cytokine profile in patients with lymphoma during the myelosuppression stage of infection. 52 patients with gram-negative bacterial infection (G- group), 49 patients with gram-positive bacterial infection (G+ group), 51 uninfected patients with lymphoma (uninfected group) and 20 healthy controls (healthy group) were enrolled in this study. We evaluated the quantification of Th1/Th2 cytokines with flow cytometry bead assay (CBA) in the sera to explore a rapid diagnostic method to determine the type of infection and anti-infective effect. The levels of procalcitonin (PCT) were also detected simultaneously. The four groups did not differ with regard to IL-2 and IL-4 (P>0.05). The IFN-γ and TNF-α levels of patients with lymphoma were higher than those of healthy controls (P<0.05). There was significantly upregulated IL-6 and IL-10 expression in the G- group (P<0.001). A similar trend was reflected in the IL-6 of the G+ group, which was significantly increased (P<0.001). However, no significant upregulation was observed for IL-10 in the G+ group. According to the different degrees of increased IL-6 and IL-10 levels, We proposed to use the G- Bacterial Infection Cytokine Profile (G- BICP) and the G+ Bacterial Infection Cytokine Profile (G+ BICP) for the first time to differentiate between Gram-negative and Gram-positive (G-/G+) bacterial infection in adults with lymphoma in the myelosuppression stage after chemotherapy. The IL-6, IL-10 and PCT in the G- group and the IL-6, PCT in the G+ group were significantly decreased at day 4 and day 8 compared with those at day 1. IL-6 and IL-10 are closely associated with the severity and treatment efficacy in adults with lymphomas who develop infections after chemotherapy and can help distinguish between G- and G+ bacterial infections at an early stage.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

The Prognostic Value of Presepsin for Sepsis in Abdominal Surgery: A Prospective Study

INTRODUCTION

Rapid diagnosis accompanied by appropriate treatment is essential in the therapy of sepsis. However, there is no blood marker available, which reliably predicts sepsis and associated mortality. Therefore, the aim of the present study was to evaluate presepsin and endotoxin in comparison with established blood markers in patients undergoing emergency visceral surgery for abdominal infection.

PATIENTS AND METHODS

This prospective study included 31 patients with abdominal infection undergoing emergency surgery between March and August 2014. The Sepsis-2 and Sepsis-3 definitions of sepsis were used. Blood markers (presepsin, endotoxin, C-reactive protein, procalcitonin (PCT), interleukin 6 (IL-6), white blood count) were analyzed preoperatively and correlated with the clinical course and mortality. Additionally, a combination of the three markers, which performed best, was tested.

RESULTS

Twenty patients (64.5%) in the analyzed cohort developed sepsis from an abdominal focus according to the latest sepsis definition. Out of the analyzed blood markers, presepsin exhibited the highest area under the curve, sensitivity, and specificity for the prediction of the development of sepsis. Moreover, presepsin had the highest predictive value for mortality as opposed to both endotoxin and previously established blood markers (i.e., PCT, IL-6). The multimarker approach, which included PCT, IL-6, and presepsin, showed no additional predictive value over presepsin alone.

CONCLUSION

The present study suggests that presepsin is a novel predictor of sepsis and mortality from sepsis in patients undergoing surgery for intra-abdominal infections. The findings of the present study should be validated in a larger cohort.

Effectiveness of Continuous Aerobic Versus High-Intensity Interval Training on Atherosclerotic and Inflammatory Markers in Boys With Overweight/Obesity

PURPOSE

Atherosclerosis is a complex multifactorial disease whose first steps can be initiated from childhood. Therefore, we examined the effects of 2 training models on salusins levels, inflammatory markers, and lipid profile in boys with overweight/obesity.

METHOD

Forty-five boys with overweight/obesity with the mean age of 11.06 (1.0) years were randomly divided into three groups of 15: a high-intensity interval training (HIIT) group (100%-110% of maximum aerobic speed); an aerobic training group (40%-70% of heart rate reserve); and a control group. The intervention included 3 sessions per week for 12 weeks.

RESULTS

Findings showed significant improvements in serum levels of salusins, salusins ratio, interleukin-6 (IL-6), and total cholesterol (TC) in both training groups (P < .001). Also, the serum levels of C-reactive protein (CRP), triglycerides (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), atherogenic index of plasma (AIP), and cholesterol index improved significantly (P < .01). Except for the TG, HIIT caused higher improvements than aerobic training (P < .001 for salusin-α, salusins ratio, IL-6, CRP, TC, HDL, AIP, and cholesterol index; and P < .01 for salusin-β and LDL).

CONCLUSION

The present study shows that HIIT has more positive effects than aerobic exercise on the atherosclerotic and inflammatory factors, as well as lipid profile variables in children with overweight/obesity.

Combining Blood-Based Biomarkers to Predict Mortality of Sepsis at Arrival at the Emergency Department

Background

Our aim was to determine a useful combination of blood biomarkers that can predict 28-day mortality of sepsis upon arrival at the Emergency Department (ED).

Material/Methods

Based on Sepsis-3.0, 90 sepsis patients were enrolled and divided into survivor and nonsurvivor groups with day 28 as the study end point. After comparing the demographic data and clinical characteristics of patients, we evaluated the predictive validity of a combination of markers including interleukin-6 (IL-6), procalcitonin (PCT), and lactate at arrival at the ED. Independent risk factors were found by using univariate and multivariate logistic regression analyses, and the prognostic value of markers was determined by the area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

Results

There were 67 (74.4%) survivors and 23 (25.6%) nonsurvivors. The levels of IL-6 (survivors vs nonsurvivors: median 205.30 vs 3499.00 pg/mL, P=0.012) and lactate (survivors vs nonsurvivors: median 2.37 vs 5.77 mmol/L, P=0.003) were significantly lower in survivor group compared with the nonsurvivor group. Markers including IL-6, PCT, lactate, and neutrophil-to-white blood cell ratio (NWR) were independent risk factors in predicting 28-day mortality due to sepsis. The combination of these 4 markers provided the best predictive performance for 28-day mortality of patients with sepsis, on arrival at the ED (AUC of 0.823, 95% confidence interval [CI] 0.723–0.924), and its accuracy, specificity, and sensitivity were 74.4% (95% CI 64.0–82.8%), 91% (95% CI 80.9–96.3%), and 65% (95% CI 42.8–82.8%), respectively.

Conclusions

The combination of IL-6, PCT, lactate, and NWR measurements is a potential predictor of 28-day mortality for patients with sepsis, at arrival at the ED. Further research is needed to confirm our findings.

Association between low body mass index and increased 28-day mortality of severe sepsis in Japanese cohorts

Current research regarding the association between body mass index (BMI) and altered clinical outcomes of sepsis in Asian populations is insufficient. We investigated the association between BMI and clinical outcomes using two Japanese cohorts of severe sepsis (derivation cohort, Chiba University Hospital, n = 614; validation cohort, multicenter cohort, n = 1561). Participants were categorized into the underweight (BMI < 18.5) and non-underweight (BMI ≥ 18.5) groups. The primary outcome was 28-day mortality. Univariate analysis of the derivation cohort indicated increased 28-day mortality trend in the underweight group compared to the non-underweight group (underweight 24.4% [20/82 cases] vs. non-underweight 16.0% [85/532 cases]; p = 0.060). In the primary analysis, multivariate analysis adjusted for baseline imbalance revealed that patients in the underweight group had a significantly increased 28-day mortality compared to those in the non-underweight group (p = 0.031, adjusted odds ratio [OR] 1.91, 95% confidence interval [CI] 1.06–3.46). In a repeated analysis using a multicenter validation cohort (underweight n = 343, non-underweight n = 1218), patients in the underweight group had a significantly increased 28-day mortality compared to those in the non-underweight group (p = 0.045, OR 1.40, 95% CI 1.00–1.97). In conclusion, patients with a BMI < 18.5 had a significantly increased 28-day mortality compared to those with a BMI ≥ 18.5 in Japanese cohorts with severe sepsis.

The predictive and diagnostic ability of IL-6 for postoperative urosepsis in patients undergoing percutaneous nephrolithotomy

The aim of this study is to investigate the predictive and diagnostic ability of interleukin-6 (IL-6) for postoperative urosepsis in patients undergoing percutaneous nephrolithotomy (PCNL). 90 patients undergoing PCNL between April 2019 and September 2019 were studied. 16 patients progressed to urosepsis (EXP1 group, n = 16) and 74 patients did not (CON group, n = 74); demographic and perioperative data were compared between these two groups. 25 patients who progressed to postoperative urosepsis without receiving the test of IL-6 between March 2018 and March 2019 were enrolled (EXP2 group, n = 25); demographic and perioperative data were compared between EXP1 group and EXP2 group. Compared with CON group, EXP1 group showed higher serum levels of IL-6 (p < 0.001) and neutrophil (p < 0.001) at postoperative hour two; higher serum levels of IL-6 (p < 0.001), procalcitonin (PCT) (p < 0.05), white blood cell (WBC) (p < 0.05), and neutrophil (p < 0.001) on postoperative day one; higher serum levels of PCT (p < 0.05) and WBC (p < 0.05) on postoperative day three. ROC curves showed IL-6 (AUC = 1.000) at postoperative hour two and PCT (AUC = 0.954) on postoperative day three. Compared with EXP2 group, EXP1 group showed shorter time to intervene (p < 0.001), a shorter postoperative hospital stay (p < 0.001), and a lower incidence rate of severe urosepsis (p < 0.05). There were different diagnostic abilities of IL-6, PCT, WBC, and neutrophil for postoperative urosepsis at different time points, and IL-6 was greatly valuable as a predictive and early diagnosing biomarker for postoperative urosepsis in patients undergoing PCNL at postoperative hour two and on postoperative day one.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Acute respiratory distress syndrome due to COVID-19. Clinical and prognostic features from a medical Critical Care Unit in Valencia, Spain

OBJECTIVE

Information from critically ill coronavirus disease 2019 (COVID-19) patients is limited and in many cases coming from health systems approaches different from the national public systems existing in most countries in Europe. Besides, patient follow-up remains incomplete in many publications. Our aim is to characterize acute respiratory distress syndrome (ARDS) patients admitted to a medical critical care unit (MCCU) in a referral hospital in Spain.

DESIGN

Retrospective case series of consecutive ARDS COVID-19 patients admitted and treated in our MCCU.

SETTING

36-bed MCCU in referral tertiary hospital.

PATIENTS AND PARTICIPANTS

SARS-CoV-2 infection confirmed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay of nasal/pharyngeal swabs.

INTERVENTIONS

None MAIN VARIABLES OF INTEREST: Demographic and clinical data were collected, including data on clinical management, respiratory failure, and patient mortality.

RESULTS

Forty-four ARDS COVID-19 patients were included in the study. Median age was 61.50 (53.25 - 67) years and most of the patients were male (72.7%). Hypertension and dyslipidemia were the most frequent co-morbidities (52.3 and 36.4% respectively). Steroids (1mg/Kg/day) and tocilizumab were administered in almost all patients (95.5%). 77.3% of the patients needed invasive mechanical ventilation for a median of 16 days [11-28]. Prone position ventilation was performed in 33 patients (97%) for a median of 3 sessions [2-5] per patient. Nosocomial infection was diagnosed in 13 patients (29.5%). Tracheostomy was performed in ten patients (29.4%). At study closing all patients had been discharged from the CCU and only two (4.5%) remained in hospital ward. MCCU length of stay was 18 days [10-27]. Mortality at study closing was 20.5% (n 9); 26.5% among ventilated patients.

CONCLUSIONS

The seven-week period in which our MCCU was exclusively dedicated to COVID-19 patients has been challenging. Despite the severity of the patients and the high need for invasive mechanical ventilation, mortality was 20.5%.

Acute respiratory distress syndrome due to COVID-19. Clinical and prognostic features from a medical Critical Care Unit in Valencia, Spain

Objective

Information from critically ill coronavirus disease 2019 (COVID-19) patients is limited and in many cases coming from health systems approaches different from the national public systems existing in most countries in Europe. Besides, patient follow-up remains incomplete in many publications. Our aim is to characterize acute respiratory distress syndrome (ARDS) patients admitted to a medical critical care unit (MCCU) in a referral hospital in Spain.

Design

Retrospective case series of consecutive ARDS COVID-19 patients admitted and treated in our MCCU.

Setting

36-bed MCCU in referral tertiary hospital.

Patients and participants

SARS-CoV-2 infection confirmed by real-time reverse transcriptase–polymerase chain reaction (RT-PCR) assay of nasal/pharyngeal swabs.

Interventions

None

Main variables of interest

Demographic and clinical data were collected, including data on clinical management, respiratory failure, and patient mortality.

Results

Forty-four ARDS COVID-19 patients were included in the study. Median age was 61.50 (53.25 – 67) years and most of the patients were male (72.7%). Hypertension and dyslipidemia were the most frequent co-morbidities (52.3 and 36.4% respectively). Steroids (1mg/Kg/day) and tocilizumab were administered in almost all patients (95.5%). 77.3% of the patients needed invasive mechanical ventilation for a median of 16 days [11-28]. Prone position ventilation was performed in 33 patients (97%) for a median of 3 sessions [2-5] per patient. Nosocomial infection was diagnosed in 13 patients (29.5%). Tracheostomy was performed in ten patients (29.4%). At study closing all patients had been discharged from the CCU and only two (4.5%) remained in hospital ward. MCCU length of stay was 18 days [10-27]. Mortality at study closing was 20.5% (n 9); 26.5% among ventilated patients.

Conclusions

The seven-week period in which our MCCU was exclusively dedicated to COVID-19 patients has been challenging. Despite the severity of the patients and the high need for invasive mechanical ventilation, mortality was 20.5%.

Prognostic Value of Immunosuppressive Acidic Protein and Oxidative Stress Status in Critically Ill Patients

Introduction

The aim of this study was to determine the prognostic value of admission immunosuppressive acidic protein (IAP), interleukin-6 (IL-6), total oxidant status (TOS), and total antioxidant status (TAS) in 161 critically ill patients.

Materials and methods

This prospective observational study was carried out in the Emergency Department ICU for 6 months. Critically ill patients were included in the study consecutively. The main outcomes were the need for early mechanical ventilation (MV) and in-hospital mortality.

Results

The mean age of 161 patients was 66.5 ± 17.1 years. The median IL-6 levels of patients who required early MV were significantly higher than of the patients who required no MV (p < 0.001), and the median IL-6 levels in the nonsurvivors were significantly higher than in the survivors (p < 0.001). The median IAP levels were not significantly different between the groups (p = 0.464 for early MV and p = 0.340 for the in-hospital mortality group). The AUCs of IL-6 and TOS for predicting in-hospital mortality were 0.819 and 0.608, respectively.

Conclusion

The IAP level on admission to ICU is ineffective in predicting the need for early MV and in-hospital mortality; however, IL-6 level on admission is a strong prognostic predictor in critically ill patients. Our findings showed that the burden of oxidative stress was high in general ICU patients.

Clinical significance

Our study showed that increased oxidative stress is an important problem in critically ill patients. If measures are taken to reduce oxidative stress by physicians, the prognosis of critically ill patients will be better.

How to cite this article

Tutuncu EO, Dundar ZD, Kilinc I, Tutuncu A, Kocak S, Girisgin AS. Prognostic Value of Immunosuppressive Acidic Protein and Oxidative Stress Status in Critically Ill Patients. Indian J Crit Care Med 2021;25(4):405–410.

Blood Interleukin-6 Levels Predict Multiple Organ Dysfunction in Critically Ill Patients

BACKGROUND

Predicting multiple organ dysfunction (MOD) in the late phase of critical illnesses is essential. Cytokines are considered biomarkers that can predict clinical outcomes; however, their predictive value for late-phase MOD is unknown. This study aimed to identify the biomarker with the highest predictive value for late-phase MOD.

METHODS

This observational study prospectively evaluated data on adult patients with systemic inflammatory response syndrome, those who presented to the emergency department or were admitted to intensive care units in five tertiary hospitals (n = 174). Seven blood biomarkers levels (interleukin-6 [IL-6], IL-8, IL-10, tumor-necrosis factor-α, white blood cells, C-reactive protein, and procalcitonin) were measured at three timepoints (days 0, 1, and 2). The area under the receiver operating characteristic curve (AUC) was analyzed to evaluate predictive values for MOD (primary outcome, MOD on day 7 [late-phase]; secondary outcome, MOD on day 3 [early-phase]).

RESULTS

Of the measured 7 biomarkers, blood IL-6 levels on day 2 had the highest predictive value for MOD on day 7 using single timepoint data (AUC 0.825, 95% confidence interval [CI] 0.754-0.879). Using three timepoint biomarkers, blood IL-6 levels had the highest predictive value of MOD on day 7 (AUC 0.838, 95% CI 0.768-0.890). Blood IL-6 levels using three timepoint biomarkers had also the highest predictive value for MOD on day 3 (AUC 0.836, 95% CI 0.766-0.888).

CONCLUSION

Of the measured biomarkers, blood IL-6 levels had the highest predictive value for MOD on days 3 and 7. Blood IL-6 levels predict early- and late-phase MOD in critically ill patients.

Biochemical Research of the Effects of Essential Oil Obtained from the Fruit of Myrtus communis L. on Cell Damage Associated with Lipopolysaccharide-Induced Endotoxemia in a Human Umbilical Cord Vein Endothelial Cells

The aim of this study to investigate the potential effects of essential oils and compounds obtained from MC fruit on sepsis induced endothelial cell damage in human umbilical cord vein endothelial cells (HUVECs) at molecular and cellular levels on in vitro sepsis model. A sepsis model was induced by the application of LPS. The HUVEC treatment groups were as follows: control, LPS, MC, MC plus LPS, 1.8 cineole, 1.8 cineole plus LPS, α-pinene, α-pinene plus LPS, α-terpineol, and α-terpineol plus LPS. Following the treatments, cell proliferation was analyzed using the xCELLigence® system. The mRNA expression of various cytokines [tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and IL-6] and endothelial nitric oxide (eNOS) were determined by quantitative polymerase chain reaction (qPCR) analysis. The 1.8 cineole and α-pinene treatments at specific doses showed toxic effects on α-terpineine, although it did not result in a change in the cellular index as compared with that of the control group. The application of LPS to HUVECs led to a significant decrease in the cellular index, depending on the treatment time. It did not correct the decreased cell index of MC plus LPS and α-terpineol plus LPS groups as compared with that of the LPS-only group. The 1.8 cineole plus LPS treatment and α-pinene plus LPS treatment significantly increased the cell index as compared with that of the LPS-only treatment, and the cell index in these groups was closer to that of the control. According to the results of the qPCR analysis, neither the MC-only treatment nor the α-terpineol-only treatment significantly reduced cellular damage caused by LPS-induced increases in TNF-α, IL-1β, IL-6, and eNOS mRNA expression. However, both the 1.8 cineole treatment and α-pinene treatments significantly decreased TNF-α, IL-1β, IL-6, and eNOS mRNA expression induced by LPS. Volatile oil obtained from MC fruit and the MC compound α-terpineol had no effect on the decreased cell index and increased cytokine response due to LPS-induced endothelial cell damage. However, 1.8 cineole and α-pinene, other major components of MC fruit, ameliorated LPS-induced damage in HUVECs at cellular and biomolecular levels (TNF-α, IL-1β, IL-6, and eNOS).

Score performance of SAPS 2 and SAPS 3 in combination with biomarkers IL-6, PCT or CRP

OBJECTIVE

We aimed to evaluate the effects of combining the Simplified-Acute-Physiology-Score (SAPS) 2 or the SAPS 3 with Interleukin-6 (IL-6) or Procalcitonin (PCT) or C-Reactive Protein (CRP) concentrations for predicting in-hospital mortality.

MATERIAL AND METHODS

This retrospective study was conducted in an interdisciplinary 22-bed intensive care unit (ICU) at a German university hospital. Within an 18-month period, SAPS 2 and SAPS 3 were calculated for 514 critically ill patients that were admitted to the internal medicine department. To evaluate discrimination performance, the area under the receiver operating characteristic curves (AUROCs) and the 95% confidence intervals (95% CIs) were calculated for each score, exclusively or in combination with IL-6 or PCT or CRP. DeLong test was used to compare different AUROCs.

RESULTS

The SAPS 2 exhibited a better discrimination performance than SAPS 3 with AUROCs of 0.81 (95% CI, 0.76-0.86) and 0.72 (95% CI, 0.66-0.78), respectively. Overall, combination of the SAPS 2 with IL-6 showed the best discrimination performance (AUROC 0.82; 95% CI, 0.77-0.87), albeit not significantly different from SAPS2. IL-6 performed better than PCT and CRP with AUROCs of 0.75 (95% CI, 0.69-0.81), 0.72 (95% CI, 0.66-0.77) and 0.65 (95% CI, 0.59-0.72), respectively. Performance of the SAPS 3 improved significantly when combined with IL-6 (AUROC 0.76; 95% CI, 0.69-0.81) or PCT (AUROC 0.73; 95% CI, 0.67-0.78).

CONCLUSIONS

Our analysis provided evidence that the risk stratification performance of the SAPS 3 and, to a lesser degree, also of the SAPS 2 can increase when combined with IL-6. A more accurate detection of aberrant or dysregulated systemic immunological responses (by IL-6) may explain the higher performance achieved by SAPS 3 + IL-6 vs. SAPS 3. Thus, implementation of IL-6 in critical care scores can improve prediction outcomes, especially in patients experiencing acute inflammatory conditions; however, statistical results may vary across hospital types and/or patient populations with different case mix.

The role of IL-6 and other mediators in the cytokine storm associated with SARS-CoV-2 infection

The coronavirus disease 2019 pandemic caused by severe acute respiratory syndrome coronavirus 2 presents with a spectrum of clinical manifestations from asymptomatic or mild, self-limited constitutional symptoms to a hyperinflammatory state ("cytokine storm") followed by acute respiratory distress syndrome and death. The objective of this study was to provide an evidence-based review of the associated pathways and potential treatment of the hyperinflammatory state associated with severe acute respiratory syndrome coronavirus 2 infection. Dysregulated immune responses have been reported to occur in a smaller subset of those infected with severe acute respiratory syndrome coronavirus 2, leading to clinical deterioration 7 to 10 days after initial presentation. A hyperinflammatory state referred to as cytokine storm in its severest form has been marked by elevation of IL-6, IL-10, TNF-α, and other cytokines and severe CD4+ and CD8+ T-cell lymphopenia and coagulopathy. Recognition of at-risk patients could permit early institution of aggressive intensive care and antiviral and immune treatment to reduce the complications related to this proinflammatory state. Several reports and ongoing clinical trials provide hope that available immunomodulatory therapies could have therapeutic potential in these severe cases. This review highlights our current state of knowledge of immune mechanisms and targeted immunomodulatory treatment options for the current coronavirus disease 2019 pandemic.

Physician Judgment and Circulating Biomarkers Predict 28-Day Mortality in Emergency Department Patients

OBJECTIVES

To determine whether biomarkers of endothelial activation and inflammation provide added value for prediction of in-hospital mortality within 28 days when combined with physician judgment in critically ill emergency department patients.

DESIGN

Prospective, observational study.

SETTING

Two urban, academic emergency departments, with ≈80,000 combined annual visits, between June 2016 and December 2017.

PATIENTS

Admitted patients, greater than 17 years old, with two systemic inflammatory response syndrome criteria and organ dysfunction, systolic blood pressure less than 90 mm Hg, or lactate greater than 4.0 mmol/L. Patients with trauma, intracranial hemorrhage known prior to arrival, or without available blood samples were excluded.

INTERVENTIONS

Emergency department physicians reported likelihood of in-hospital mortality (0-100%) by survey at hospital admission. Remnant EDTA blood samples, drawn during the emergency department stay, were used to measure angiopoietin-1, angiopoietin-2, tumor necrosis factor receptor-1, interleukin-6, and interleukin-8.

MEASUREMENTS AND MAIN RESULTS

We screened 421 patients and enrolled 314. The primary outcome of in-hospital mortality within 28 days occurred in 31 (9.9%). When predicting the primary outcome, the best biomarker model included angiopoietin-2 and interleukin-6 and performed moderately well (area under the curve, 0.72; 95% CI, 0.69-0.75), as did physician judgment (area under the curve, 0.78; 95% CI, 0.74-0.82). Combining physician judgment and biomarker models improved performance (area under the curve, 0.85; 95% CI, 0.82-0.87), with area under the curve change of 0.06 (95% CI, 0.04-0.09; p < 0.01) compared with physician judgment alone.

CONCLUSIONS

Predicting in-hospital mortality within 28 days among critically ill emergency department patients may be improved by including biomarkers of endothelial activation and inflammation in combination with emergency department physician judgment.

A 2020 review on the role of procalcitonin in different clinical settings: an update conducted with the tools of the Evidence Based Laboratory Medicine

Biomarkers to guide antibiotic treatment decisions have been proposed as an effective way to enhancing a more appropriate use of antibiotics. As a biomarker, procalcitonin (PCT) has been found to have good specificity to distinguish bacterial from non-bacterial inflammations. Decisions regarding antibiotic use in an individual patient are complex and should be based on the pre-test probability for bacterial infection, the severity of presentation and the results of PCT serum concentration. In the context of a high pre-test probability for bacterial infections and/or a high-risk patient with sepsis, monitoring of PCT over time helps to track the resolution of infection and decisions regarding early stop of antibiotic treatment. As outlined by the Evidence Based Laboratory Medicine (EBLM), not only the pre-test probability but also the positive likelihood ratio influence the performance of a test do be really diagnostic. This aspect should be taken into account in the interpretation of the results of clinical trials evaluating the performance of PCT in guiding antibiotic therapy.

Clinical implications of elevated serum interleukin-6 in IgG4-related disease

Introduction

Some patients with IgG4-related disease (IgG4-RD) exhibit elevated serum interleukin (IL)-6 with excessive inflammatory reactions or with repeating relapse. To date few reports pertaining to clinical implications of elevated serum IL-6 in IgG4-RD patients have been published. The aims of the current retrospective study were to investigate the clinical implications of elevated serum IL-6 in IgG4-RD patients, and to examine whether IL-6 can predict the activity and/or relapse of the disease.

Materials and methods

We examined the clinical picture at the onset of 43 patients who were diagnosed with IgG4-RD in our hospital and were able to measure serum IL-6 before steroid treatment.

Results

The median level of serum IL-6 was 2.2 pg/mL. There was a significant correlation between IL-6 and C-reactive protein (CRP) level (r = 0.397, p = 0.008), hemoglobin level (r = -0.390, p = 0.010) and albumin level (r = -0.556, p < 0.001). When 43 patients were divided into two groups by using a cut-off IL-6 of 4 pg/mL, the high IL-6 group showed higher age, lower albumin, higher CRP and higher aspartate aminotransferase (AST) (age p = 0.014, albumin p = 0.006, CRP p <0.001, AST p = 0.009). Hepatic swelling and splenomegaly were significantly more prevalent in the high IL-6 group than it was in the low IL-6 group (liver p < 0.001, spleen p = 0.020). Biliary tract involvement tended to admit more in the high IL-6 group (p = 0.060).

Conclusion

Serum IL-6 level at the onset of IgG4-RD may be significantly correlated with clinical inflammatory parameters and it may also be associated with involvement of the bile duct, liver, and spleen.

Diagnostic and prognostic value of interleukin-6, pentraxin 3, and procalcitonin levels among sepsis and septic shock patients: a prospective controlled study according to the Sepsis-3 definitions

Background

This study investigated the clinical value of interleukin-6 (IL-6), pentraxin 3 (PTX3), and procalcitonin (PCT) in patients with sepsis and septic shock diagnosed according to the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3).

Methods

Serum levels of IL-6, PTX3, and PCT were measured in 142 enrolled subjects (51 with sepsis, 46 with septic shock, and 45 as controls). Follow-up IL-6 and PTX3 levels were measured in patients with initial septic shock within 24 h of hospital discharge. Optimal cut-off values were determined for sepsis and septic shock, and prognostic values were evaluated.

Results

Serum IL-6 levels could discriminate sepsis (area under the curve [AUC], 0.83–0.94, P <  0.001; cut-off value, 52.60 pg/mL, 80.4% sensitivity, 88.9% specificity) from controls and could distinguish septic shock (AUC, 0.71–0.89; cut-off value, 348.92 pg/mL, 76.1% sensitivity, 78.4% specificity) from sepsis. Twenty-eight-day mortality was significantly higher in the group with high IL-6 (≥ 348.92 pg/mL) than in the group with low IL-6 (< 348.92 pg/mL) (P = 0.008). IL-6 was an independent risk factor for 28-day mortality among overall patients (hazard ratio, 1.0004; 95% confidence interval, 1.0003–1.0005; p = 0.024). In septic shock patients, both the initial and follow-up PTX3 levels were consistently significantly higher in patients who died than in those who recovered (initial p = 0.004; follow-up P <  0.001).

Conclusions

The diagnostic and prognostic value of IL-6 was superior to those of PTX3 and PCT for sepsis and septic shock.

Interleukin-6 improves infection identification when added to physician judgment during evaluation of potentially septic patients

BACKGROUND

Identifying infection is critical in early sepsis screening. This study assessed whether biomarkers of endothelial activation and/or inflammation could improve identification of infection among Emergency Department (ED) patients with organ dysfunction.

METHODS

We performed a prospective, observational study at two urban, academic EDs, between June 2016 and December 2017. We included admitted adults with 1) two systemic inflammatory response syndrome criteria and organ dysfunction, 2) systolic blood pressure < 90 mmHg, or 3) lactate ≥4.0 mmol/L. We excluded patients with trauma, transferred for intracranial hemorrhage, or without available blood samples. Treating ED physicians reported presence of infection (yes/no) at inpatient admission. Assays for angiopoietin-1, angiopoietin-2, soluble tumor necrosis factor receptor-1, interleukin-6, and interleukin-8 were performed using ED blood samples. The primary outcome was infection, adjudicated by paired physician review. Using logistic regression, we compared the performance of physician judgment, biomarkers, and physician judgment-biomarkers combination to predict infection. Area under the curve (AUC) and AUC 95% confidence intervals were estimated by bootstrap procedure.

RESULTS

Of 421 patients enrolled, 306 patients met final study criteria. Of these, 154(50.3%) patients had infectious etiologies. Physicians correctly discriminated infectious from non-infectious etiologies in 239 (78.1%). Physician judgment performed moderately when discriminating infection (AUC 0.78, 95% CI: 0.74-0.82) and outperformed the best biomarker model, interleukin-6 alone, (AUC 0.71, 0.66-0.76). Physician judgment improved when including interleukin-6 (AUC 0.84, 0.79-0.87), with modest AUC improvement: 0.06 (0.03-0.08).

CONCLUSIONS

In ED patients with organ dysfunction, plasma interleukin-6 may improve infection discrimination when added to physician judgment.

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.

Plasma interleukin-6 concentration for the diagnosis of sepsis in critically ill adults

BACKGROUND

The definition of sepsis has evolved over time, along with the clinical and scientific knowledge behind it. For years, sepsis was defined as a systemic inflammatory response syndrome (SIRS) in the presence of a documented or suspected infection. At present, sepsis is defined as a life-threatening organ dysfunction resulting from a dysregulated host response to infection. Even though sepsis is one of the leading causes of mortality in critically ill patients, and the World Health Organization (WHO) recognizes it as a healthcare priority, it still lacks an accurate diagnostic test. Determining the accuracy of interleukin-6 (IL-6) concentrations in plasma, which is proposed as a new biomarker for the diagnosis of sepsis, might be helpful to provide adequate and timely management of critically ill patients, and thus reduce the morbidity and mortality associated with this condition.

OBJECTIVES

To determine the diagnostic accuracy of plasma interleukin-6 (IL-6) concentration for the diagnosis of bacterial sepsis in critically ill adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, and Web of Science on 25 January 2019. We screened references in the included studies to identify additional studies. We did not apply any language restriction to the electronic searches.

SELECTION CRITERIA

We included diagnostic accuracy studies enrolling critically ill adults aged 18 years or older under suspicion of sepsis during their hospitalization, where IL-6 concentrations were evaluated by serological measurement.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and extracted data. We assessed the methodological quality of studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We estimated a summary receiver operating characteristic (SROC) curve by fitting a hierarchical summary ROC (HSROC) non-linear mixed model. We explored sources of heterogeneity using the HSROC model parameters. We conducted all analyses in the SAS statistical software package and R software.

MAIN RESULTS

We included 23 studies (n = 4192) assessing the accuracy of IL-6 for the diagnosis of sepsis in critically ill adults. Twenty studies that were available as conference proceedings only are awaiting classification. The included participants were heterogeneous in terms of their distribution of age, gender, main diagnosis, setting, country, positivity threshold, sepsis criteria, year of publication, and origin of infection, among other factors. Prevalence of sepsis greatly varied across studies, ranging from 12% to 78%. We considered all studies to be at high risk of bias due to issues related to the index test domain in QUADAS-2. The SROC curve showed a great dispersion in individual studies accuracy estimates (21 studies, 3650 adult patients), therefore the considerable heterogeneity in the collected data prevented us from calculating formal accuracy estimates. Using a fixed prevalence of sepsis of 50% and a fixed specificity of 74%, we found a sensitivity of 66% (95% confidence interval 60 to 72). If we test a cohort 1000 adult patients under suspicion of sepsis with IL-6, we will find that 330 patients would receive appropriate and timely antibiotic therapy, while 130 patients would be wrongly considered to have sepsis. In addition, 370 out of 1000 patients would avoid unnecessary antibiotic therapy, and 170 patients would have been undiagnosed of sepsis. This numerical approach should be interpreted with caution due to the limitations described above.

AUTHORS' CONCLUSIONS

Our evidence assessment of plasma interleukin-6 concentrations for the diagnosis of sepsis in critically ill adults reveals several limitations. High heterogeneity of collected evidence regarding the main diagnosis, setting, country, positivity threshold, sepsis criteria, year of publication, and the origin of infection, among other factors, along with the potential number of misclassifications, remain significant constraints for its implementation. The 20 conference proceedings assessed as studies awaiting classification may alter the conclusions of the review once they are fully published and evaluated. Further studies about the accuracy of interleukin-6 for the diagnosis of sepsis in adults that apply rigorous methodology for conducting diagnostic test accuracy studies are needed. The conclusions of the review will likely change once the 20 studies pending publication are fully published and included.

Diagnostic value of procalcitonin and presepsin for sepsis in critically ill adult patients: a systematic review and meta-analysis

Background

Early and accurate diagnosis of sepsis is challenging. Although procalcitonin and presepsin have been identified as potential biomarkers to differentiate between sepsis and other non-infectious causes of systemic inflammation, the diagnostic accuracy of these biomarkers remains controversial. Herein, we performed a comprehensive meta-analysis to assess the overall diagnostic value of procalcitonin and presepsin for the diagnosis of sepsis.

Methods

We searched three electronic databases (MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials) for relevant studies. Two authors independently screened articles on the basis of inclusion and exclusion criteria. The pooled sensitivity, specificity, and summary receiver operating characteristic curves were estimated. The quality of evidence for diagnostic accuracy in absolute effects, i.e., the number of true or false positives and true or false negatives, gave a particular pre-test probability.

Results

We included 19 studies (19 observational studies and no randomized controlled trials) that had enrolled 3012 patients. Analyses of summary receiver operating characteristic curves revealed areas under the receiver operating characteristic curves of 0.84 for procalcitonin and 0.87 for presepsin. The pooled sensitivities and specificities were 0.80 (95% confidence interval 0.75 to 0.84) and 0.75 (95% confidence interval 0.67 to 0.81) for procalcitonin. For presepsin, these values were 0.84 (95% confidence interval 0.80 to 0.88) and 0.73 (95% confidence interval 0.61 to 0.82), respectively. There were no statistically significant differences in both pooled sensitivities (p = 0.48) and specificities (p = 0.57) between procalcitonin and presepsin.

Conclusion

Our meta-analysis provided evidence that the diagnostic accuracy of procalcitonin and presepsin in detecting infection was similar and that both are useful for early diagnosis of sepsis and subsequent reduction of mortality in critically ill adult patients.

Systematic review registration

The study was registered in PROSPERO under the registration number CRD42016035784.

Electronic supplementary material

The online version of this article (10.1186/s40560-019-0374-4) contains supplementary material, which is available to authorized users.

Pathophysiology of Acute Illness and Injury

The pathophysiology of acute illness and injury recognizes three main effectors: infection, trauma, and ischemia-reperfusion injury. Each of them can act by itself or in combination with the other two in developing a systemic inflammatory reaction syndrome (SIRS) that is a generalized reaction to the morbid event. The time course of SIRS is variable and influenced by the number and severity of subsequent insults (e.g., reparative surgery, acquired hospital infections). It occurs simultaneously with a complex of counter-regulatory mechanisms (compensatory anti-inflammatory response syndrome, CARS) that limit the aggressive effects of SIRS. In adjunct, a progressive dysfunction of the acquired (lymphocytes) immune system develops with increased risk for immunoparalysis and associated infectious complications. Both humoral and cellular effectors participate to the development of SIRS and CARS. The most important humoral mediators are pro-inflammatory (IL-1β, IL-6, IL-8, IL-12) and anti-inflammatory (IL-4, IL-10) cytokines and chemokines, complement, leukotrienes, and PAF. Effector cells include neutrophils, monocytes, macrophages, lymphocytes, and endothelial cells. The endothelium is a key factor for production of remote organ damage as it exerts potent chemo-attracting effects on inflammatory cells, allows for leukocyte trafficking into tissues and organs, and promotes further inflammation by cytokines release. Moreover, the loss of vasoregulatory properties and the increased permeability contribute to the development of hypotension and tissue edema. Finally, the disseminated activation of the coagulation cascade causes the widespread deposition of microthrombi with resulting maldistribution of capillary blood flow and ultimately hypoxic cellular damage. This mechanism together with increased vascular permeability and vasodilation is responsible for the development of the multiple organ dysfunction syndrome (MODS).

In vitro suppression of inflammatory cytokine response by methionine sulfoximine

Background

The glutamine synthetase inhibitor methionine sulfoximine (MSO), shown previously to prevent death caused by an inflammatory liver response in mice, was tested on in vitro production of cytokines by mouse peritoneal macrophages triggered with lipopolysaccharide (LPS).

Results

MSO significantly reduced the production of Interleukin 6 (IL-6) and Tumor Necrosis Factor Alpha (TNFα) at 4 and 6 h after LPS-treatment. This reduction did not result from decreased transcription of IL-6 and TNFα genes, and therefore appeared to result from post-transcriptional inhibition of synthesis of these cytokines. MSO treatment did not inhibit total protein synthesis and did not reduce the production of a third LPS-triggered cytokine CXCL1, so the effect was not a toxic or global downregulation of the LPS response. The anti-inflammatory effects of a glutamine synthetase inhibitor were seen even though the medium contained abundant (2 mM) glutamine, suggesting that the target for this activity was not glutamine synthetase. In agreement with this hypothesis, the L,R isomer of MSO, which does not inhibit glutamine synthetase and was previously thought to be inert, both significantly reduced IL-6 secretion in isolated macrophages and increased survival in a mouse model for inflammatory liver failure.

Conclusions

Our findings provide evidence for a novel target of MSO. Future attempts to identify the additional target would therefore also provide a target for therapies to treat diseases involving damaging cytokine responses.

Chronic Critical Illness and Persistent Inflammation: What can we Learn from the Elderly, Injured, Septic, and Malnourished?

Patients in the intensive care unit (ICU) who develop chronic critical illness significantly stress the clinical capacity and financial resources of healthcare systems. Although vast improvements have been made in critical care management, outcomes for this ICU subset remain poor. A hallmark for patients who progress to chronic critical illness is the development of persistent inflammation and immunosuppression. The risk factors associated with the development of chronic critical illness include increased age, medical comorbidities, severe injury, septic shock, and malnutrition. Interestingly, each of these clinical states bears strikingly similar immune defects, often resulting in the activation of a persistent inflammatory state. Strategies aimed at the prevention or early recognition of this state of immune compromise may help improve outcomes for these individuals and minimize the number who progress to chronic critical illness. This review explores the current knowledge regarding the immune defects associated with the development of persistent inflammation, the ways in which it can manifest clinically, attempted therapeutic interventions to date, and future insights into improving outcomes for this patient population.

Interleukin-6 as a diagnostic marker for infection in critically ill patients: A systematic review and meta-analysis

BACKGROUND

The ability of blood levels of interleukin (IL)-6 to differentiate between infection and non-infection in critically ill patients with suspected infection is unclear. We assessed the diagnostic accuracy of serum IL-6 levels for the diagnosis of infection in critically ill patients.

METHODS

We systematically searched the PubMed, MEDLINE, Cochrane Resister of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, and Igaku Chuo Zasshi databases for studies published from 1986 to August 2016 that evaluated the accuracy of IL-6 levels for the diagnosis of infection. We constructed 2 × 2 tables and calculated summary estimates of sensitivity and specificity using a bivariate random-effects model.

RESULTS

The literature search identified 775 articles, six of which with a total of 527 patients were included according to the predefined criteria. The pooled sensitivity, specificity, and diagnostic odds ratio were 0.73 (95% confidence interval [CI], 0.61-0.82), 0.76 (95% CI, 0.61-0.87), and 2.31 (95% CI, 1.20-3.48), respectively. The area under the curve (AUC) of the summary receiver operator characteristic (SROC) curve was 0.81 (95% CI, 0.78-0.85). In the secondary analysis of two studies with a total of 263 adult critically ill patients with organ dysfunction, the pooled sensitivity, specificity, and diagnostic odds ratio were 0.81 (95% CI, 0.75-0.86), 0.77 (95% CI, 0.67-0.84), and 2.87 (95% CI 2.15-3.60), respectively.

CONCLUSIONS

Blood levels of IL-6 have a moderate diagnostic value and a potential clinical utility to differentiate infection in critically ill patients with suspected infection.

Simultaneous Inhibition of Tumor Necrosis Factor Receptor 1 and Matrix Metalloproteinase 8 Completely Protects Against Acute Inflammation and Sepsis

OBJECTIVES

Sepsis causes very high mortality and morbidity rates and remains one of the biggest medical challenges. This study investigates whether plasma levels of both matrix metalloproteinase 8 and tumor necrosis factor receptor 1 are associated with sepsis severity and also investigates the therapeutic applicability of simultaneous inhibition of the two molecules in sepsis.

DESIGN

Observational human pilot study-prospective controlled animal study.

SETTING

University hospital and research laboratory.

SUBJECTS

Sepsis patients and C57BL/6 mice deficient for matrix metalloproteinase 8 and/or tumor necrosis factor receptor 1.

INTERVENTION

Plasma and whole blood RNA were collected from 13 sepsis patients for 7 consecutive days and within 24 hours of admission to ICU. Matrix metalloproteinase 8 and tumor necrosis factor receptor 1 plasma and expression levels were determined in these patients. Mice deficient for both matrix metalloproteinase 8 and tumor necrosis factor receptor 1 were generated and subjected to endotoxemia and cecal ligation and puncture. Additionally, a bispecific Nanobody that simultaneously blocks matrix metalloproteinase 8 and tumor necrosis factor receptor 1 was created.

MEASUREMENTS AND MAIN RESULTS

Plasma levels of matrix metalloproteinase 8 and tumor necrosis factor receptor 1 were positively correlated with the Sequential Organ Failure Assessment score (r, 0.51 and 0.58) and interleukin 6 levels (r, 0.59 and 0.52) in 13 sepsis patients. Combined elimination of tumor necrosis factor receptor 1 and matrix metalloproteinase 8 in double knockout mice resulted in superior survival in endotoxemia and CLP compared with single knockouts and wild-type mice. Cotreatment with our bispecific Nanobody in CLP resulted in improved survival rates (28% vs 19%) compared with untreated mice.

CONCLUSIONS

Inhibition of matrix metalloproteinase 8 and tumor necrosis factor receptor 1 might have therapeutic potential to treat sepsis and proof-of-principle was provided as therapeutics that inhibit both tumor necrosis factor receptor 1 and matrix metalloproteinase 8 are effective in CLP.

Screening cytokine/chemokine profiles in serum and organs from an endotoxic shock mouse model by LiquiChip

Studying the cytokine profiles in animal models or patients with sepsis provides an experimental basis for the identification of diagnostic biomarkers and therapeutic targets. In this study, we used a liquid protein chip (LiquiChip), also known as flexible multi-analyte profiling technology, to perform quantitative analyses of several cytokines and chemokines (e.g., IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, TNF-α, IFN-γ, granulocyte-macrophage colony-stimulating factor, keratinocyte chemoattractant, monocyte chemoattractant protein, monokine induced by gamma interferon, IFN-γ-inducible protein 10, and macrophage inflammatory protein 1 alpha). The levels of these cytokines and chemokines were determined both in the blood and in tissues, including the lung, liver, heart, kidney, spleen, brain, stomach, intestine and muscle, of mice challenged with LPS. Our data showed variable production levels of LPS-induced cytokines in different mouse organs, and the cytokine in the blood did not correlate with those in the organs. We also showed that the levels of most cytokines peaked within 1 to 6 h and decreased rapidly afterward. A variety of inflammatory cytokines might be related to the damage in different organs during septic shock. Our data also suggest that the spleen might be an important target organ in the development of systemic inflammatory response syndrome and sepsis.