Dissecting the mediating role of cytokines in the interaction between immune traits and sepsis: insights from comprehensive mendelian randomization

Background

Sepsis is a life-threatening organ dysfunction resulting from a dysregulated host response to infection, yet the potential causal relationship between the immunophenotype and sepsis remains unclear.

Methods

Genetic variants associated with the immunophenotype served as instrumental variables (IVs) in Mendelian randomization (MR) to elucidate the causal impact of the immunophenotype on three sepsis outcomes. Additionally, a two-step MR analysis was conducted to identify significant potential mediators between the immunophenotype and three sepsis outcomes.

Results

Our MR analysis demonstrated a significant association between the immunophenotype and sepsis outcome, with 36, 36, and 45 the immunophenotype associated with the susceptibility, severity, and mortality of sepsis, respectively. Specifically, our analysis highlighted the CD14+ CD16+ monocyte phenotype as a significant factor across all three sepsis outcomes, with odds ratios (ORs) and corresponding confidence intervals (CIs) indicating its impact on sepsis (OR = 1.047, CI: 1.001-1.096), sepsis in Critical Care Units (OR = 1.139, CI: 1.014-1.279), and sepsis-related 28-day mortality (OR = 1.218, CI: 1.104-1.334). Mediation analyses identified seven cytokines as significant mediators among 91 potential cytokines, including interleukin-5 (IL-5), S100A12, TNF-related apoptosis-inducing ligand (TRAIL), T-cell surface glycoprotein CD6 isoform, cystatin D, interleukin-18 (IL-18), and urokinase-type plasminogen activator (uPA). Furthermore, reverse MR analysis revealed no causal effect of sepsis outcomes on the immunophenotype.

Conclusion

Our MR study suggests that the immunophenotype is significantly associated with the susceptibility, severity, and mortality of patient with sepsis, providing, for the first time, robust evidence of significant associations between immune traits and their potential risks. This information is invaluable for clinicians and patients in making informed decisions and merits further attention.

Patient stratification using plasma cytokines and their regulators in sepsis: relationship to outcomes, treatment effect and leucocyte transcriptomic subphenotypes

RATIONALE

Heterogeneity of the host response within sepsis, acute respiratory distress syndrome (ARDS) and more widely critical illness, limits discovery and targeting of immunomodulatory therapies. Clustering approaches using clinical and circulating biomarkers have defined hyper-inflammatory and hypo-inflammatory subphenotypes in ARDS associated with differential treatment response. It is unknown if similar subphenotypes exist in sepsis populations where leucocyte transcriptomic-defined subphenotypes have been reported.

OBJECTIVES

We investigated whether inflammatory clusters based on cytokine protein abundance were seen in sepsis, and the relationships with previously described transcriptomic subphenotypes.

METHODS

Hierarchical cluster and latent class analysis were applied to an observational study (UK Genomic Advances in Sepsis (GAinS)) (n=124 patients) and two clinical trial datasets (VANISH, n=155 and LeoPARDS, n=484) in which the plasma protein abundance of 65, 21, 11 circulating cytokines, cytokine receptors and regulators were quantified. Clinical features, outcomes, response to trial treatments and assignment to transcriptomic subphenotypes were compared between inflammatory clusters.

MEASUREMENTS AND MAIN RESULTS

We identified two (UK GAinS, VANISH) or three (LeoPARDS) inflammatory clusters. A group with high levels of pro-inflammatory and anti-inflammatory cytokines was seen that was associated with worse organ dysfunction and survival. No interaction between inflammatory clusters and trial treatment response was found. We found variable overlap of inflammatory clusters and leucocyte transcriptomic subphenotypes.

CONCLUSIONS

These findings demonstrate that differences in response at the level of cytokine biology show clustering related to severity, but not treatment response, and may provide complementary information to transcriptomic sepsis subphenotypes.

TRIAL REGISTRATION NUMBER

ISRCTN20769191, ISRCTN12776039.

Early prediction of sepsis-induced respiratory tract infection using a biomarker-based machine-learning algorithm

Early and differential diagnosis of sepsis is essential to avoid unnecessary antibiotic use and further reduce patient morbidity and mortality. Here, we aimed to identify predictors of sepsis and advance a machine-learning strategy to predict sepsis-induced respiratory tract infection (RTI). Patients with sepsis and RTI were selected via retrospective analysis, and essential population characteristics and laboratory parameters were recorded. To improve the performance of the primary model and avoid over-fitting, a recursive feature elimination with cross-validation (RFECV) strategy was used to screen the optimal subset of biomarkers and construct nine machine-learning models based on this subset; the average accuracy, precision, recall, and F1-score were used for evaluation of the models. We identified 430 patients with sepsis and 686 patients with RTI. A total of 39 features were collected, with 23 features identified for initial model construction. Using the RFECV algorithm, we found that the XGBoost classifier, which only needed to include seven biomarkers, demonstrated the best performance among all prediction models, with an average accuracy of 89.24 ± 2.28, while the Ridge classifier, which included 11 biomarkers, had an average accuracy of only 83.87 ± 4.69. The remaining models had prediction accuracies greater than 88%. We developed nine models for predicting sepsis using a strategy that combined RFECV with machine learning. Among these models, the XGBoost classifier, which included seven biomarkers, showed the best performance and highest accuracy for predicting sepsis and may be a promising tool for the timely identification of sepsis.

Diagnostic value of serum CRP, PCT and IL-6 in children with nephrotic syndrome complicated by infection: a single center retrospective study

OBJECTIVE

The purpose was to look into the diagnostic value of serum CRP, PCT and IL-6 in children with nephrotic syndrome co-infection.

METHODS

One hundred and forty-nine children with nephrotic syndrome who met the inclusion and exclusion criteria were included in this study. The children were divided into three groups: bacterial infection group, non-bacterial infection group, and non-infection group. The diagnostic value was analyzed and compared using the ROC curve.

RESULTS

There was no statistically significant difference in the Leukocyte counts among three groups. The mean results of serum CRP, PCT and IL-6 were significantly higher in the bacterial infection group compared to those in the non-infection group (p < 0.05). AUC of CRP, PCT, IL-6 in bacterial infection were 0.791, 0.859, 0.783. The following combinations CRP + PCT + IL-6, IL-6 + PCT, CRP + PCT significantly increased the efficiency of bacterial infection diagnosis, the AUCs were 0.881, 0.884, and 0.884, respectively. AUC of PCT in non-bacterial infection was 0.663. The combinations of these three clinical indicators performed no better than PCT in ROC analysis.

CONCLUSION

Normal CRP or IL-6 levels do not rule out the diagnosis of bacterial infection in children on long-term glucocorticoid therapy. The appropriate combination of two or three indicators can improve the diagnostic value.

IMPACT

This study evaluated the diagnostic value of the serum concentrations of CRP, PCT and IL-6 and assessed whether the value of their combined application is better than when used alone for diagnosing primary nephrotic syndrome complicated by infection. The elevation in leukocyte count cannot be used to diagnose children with nephrotic syndromes on long-term glucocorticoid treatment who have bacterial infections. Normal CRP or IL-6 levels do not rule out the diagnosis of bacterial infection in children on long-term glucocorticoid therapy. The appropriate combination of two or three indicators can improve diagnostic value, sensitivity, and specificity.

Gossypin mitigates oxidative damage by downregulating the molecular signaling pathway in oleic acid-induced acute lung injury

One of the leading causes of acute lung injury, which is linked to a high death rate, is pulmonary fat embolism. Increases in proinflammatory cytokines and the production of free radicals are related to the pathophysiology of acute lung injury. Antioxidants that scavenge free radicals play a protective role against acute lung injury. Gossypin has been proven to have antioxidant, antimicrobial, and anti-inflammatory properties. In this study, we compared the role of Gossypin with the therapeutically used drug Dexamethasone in the acute lung injury model caused by oleic acid in rats. Thirty rats were divided into five groups; Sham, Oleic acid model, Oleic acid+Dexamethasone (0.1 mg/kg), Oleic acid+Gossypin (10 and 20 mg/kg). Two hours after pretreatment with Dexamethasone or Gossypin, the acute lung injury model was created by injecting 1 g/kg oleic acid into the femoral vein. Three hours following the oleic acid injection, rats were decapitated. Lung tissues were extracted for histological, immunohistochemical, biochemical, PCR, and SEM imaging assessment. The oleic acid injection caused an increase in lipid peroxidation and catalase activity, pathological changes in lung tissue, decreased superoxide dismutase activity, and glutathione level, and increased TNF-α, IL-1β, IL-6, and IL-8 expression. However, these changes were attenuated after treatment with Gossypin and Dexamethasone. By reducing the expression of proinflammatory cytokines and attenuating oxidative stress, Gossypin pretreatment provides a new target that is equally effective as dexamethasone in the treatment of oleic acid-induced acute lung injury.

Biomarkers in the intensive care setting: A focus on using procalcitonin and C-reactive protein to optimize antimicrobial duration of therapy

Managing the critically ill patient with infection is complex, requiring clinicians to synthesize considerable information relating to antimicrobial efficacy and treatment duration. The use of biomarkers may play an important role in identifying variation in treatment response and providing information about treatment efficacy. Though a vast number of biomarkers for clinical application have been described, procalcitonin and C-reactive protein (CRP) are the most thoroughly investigated in the critically ill. However, the presence of heterogeneous populations, variable end points, and incongruent methodology in the literature complicates the use of such biomarkers to guide antimicrobial therapy. This review focuses on an appraisal of evidence for use of procalcitonin and CRP to optimize antimicrobial duration of therapy (DOT) in critically ill patients. Procalcitonin-guided antimicrobial therapy in mixed critically ill populations with varying degrees of sepsis appears to be safe and might assist in reducing antimicrobial DOT. Compared to procalcitonin, fewer studies exist examining the impact of CRP on antimicrobial DOT and clinical outcomes in the critically ill. Procalcitonin and CRP have been insufficiently studied in many key intensive care unit populations, including surgical patients with concomitant trauma, renally insufficient populations, the immunocompromised, and patients with septic shock. We believe the available evidence is not strong enough to warrant routine use of procalcitonin or CRP to guide antimicrobial DOT in critically ill patients with infection. So long as its limitations are recognized, procalcitonin could be considered to tailor antimicrobial DOT on a case-by-case basis in the critically ill patient.

The Contribution of Procalcitonin, C-Reactive Protein and Interleukin-6 in the Diagnosis and Prognosis of Surgical Sepsis: An Observational and Statistical Study

Background

Sepsis affects over 30 million people worldwide each year, causing approximately 6 million deaths. Challenges in clinical diagnosis and the need for an early diagnosis to prevent mortality due to sepsis have led to dependence on inflammatory biomarkers like Procalcitonin (PCT), C-reactive protein (CRP), and Interleukin-6 (IL-6).

Objective

This study was performed to observe the contribution of inflammatory biomarkers in the diagnosis and prognosis of patients with surgical sepsis.

Methods

We performed a retrospective observational study in a Clinical Emergency Hospital, which included a number of 125 patients with surgical sepsis admitted between January 2020 and December 2021. The patients were included in the study based on the Sepsis-3 definition. PCT, CRP, IL-6, Sepsis-related Organ Failure Assessment (SOFA) score, Charlson Comorbidity Index (CCI), the time up to surgery, the days of treatment in Intensive Care Unit (ICU) and the total days of hospitalization had been statistically analyzed.

Results

The mean age of all patients was 65.14 years. The mean value in all patients for PCT was 20.08 ng/mL, for CRP was 175.42 mg/l, and for IL-6 was 799.6 pg/mL. The strongest correlation between biomarkers was between CRP and IL-6 (r = 0.425; p < 0.0001). Of all biomarkers, the CRP correlated the strongest with patient outcomes (r = 0.544; p < 0.0001). The area under curve (AUC) for the mean values of the inflammatory biomarkers was calculated and the best diagnostic performance was for CRP with 0.816 (95% CI: 0.744-0.887).

Conclusion

CRP and IL-6 were the most efficient in sepsis diagnosis. The association of PCT, CRP and IL-6 has increased the range of certainty in sepsis diagnosis. CRP was the most efficient biomarker in the prognosis of sepsis.

Hypothermia or hyperthermia, which is associated with patient outcomes in critically ill children with sepsis? -A retrospective study

OBJECTIVES

In the early stage of sepsis, identifying high-risk paediatric patients with a poor prognosis and providing timely and adequate treatment are critical. This study aimed to evaluate the effect of average body temperature within 24 hours of admission on the short-term prognosis of paediatric patients with sepsis.

DESIGN

A retrospective cohort study.

SETTING

A single-centre, tertiary care hospital in China, containing patient data from 2010 to 2018.

PARTICIPANTS

1144 patients with sepsis were included.

INTERVENTION

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main outcome measure was in-hospital mortality, which was defined as death from any cause during hospitalisation. The secondary outcome was the length of hospital stay.

RESULTS

The LOWESS method showed a roughly 'U'-shaped relationship between body temperature on the first day and in-hospital mortality. Multivariate logistic regression showed that severe hypothermia (OR 14.72, 95% CI 4.84 to 44.75), mild hypothermia (OR 3.71, 95% CI 1.26 to 10.90), mild hyperthermia (OR 3.41, 95% CI 1.17 to 9.90) and severe hyperthermia (OR 5.15, 95% CI 1.84 to 14.43) were independent risk factors for in-hospital mortality. Compared with other variables, the Wald χ² value of temperature on the first day minus the degree of freedom was the highest.

CONCLUSIONS

Whether hypothermic or hyperthermic, the more abnormal the temperature on the first day is, the higher the risk of in-hospital death in children with sepsis.

Developing a machine learning prediction algorithm for early differentiation of urosepsis from urinary tract infection

OBJECTIVES

Early recognition and timely intervention for urosepsis are key to reducing morbidity and mortality. Blood culture has low sensitivity, and a long turnaround time makes meeting the needs of clinical diagnosis difficult. This study aimed to use biomarkers to build a machine learning model for early prediction of urosepsis.

METHODS

Through retrospective analysis, we screened 157 patients with urosepsis and 417 patients with urinary tract infection. Laboratory data of the study participants were collected, including data on biomarkers, such as procalcitonin, D-dimer, and C-reactive protein. We split the data into training (80%) and validation datasets (20%) and determined the average model prediction accuracy through cross-validation.

RESULTS

In total, 26 variables were initially screened and 18 were statistically significant. The influence of the 18 variables was sorted using three ranking methods to further determine the best combination of variables. The Gini importance ranking method was found to be suitable for variable filtering. The accuracy rates of the six machine learning models in predicting urosepsis were all higher than 80%, and the performance of the artificial neural network (ANN) was the best among all. When the ANN included the eight biomarkers with the highest influence ranking, its model had the best prediction performance, with an accuracy rate of 92.9% and an area under the receiver operating characteristic curve of 0.946.

CONCLUSIONS

Urosepsis can be predicted using only the top eight biomarkers determined by the ranking method. This data-driven predictive model will enable clinicians to make quick and accurate diagnoses.

Microvesicles with mitochondrial content are increased in patients with sepsis and associated with inflammatory responses

BACKGROUND

Endothelial activation plays an important role in sepsis-mediated inflammation, but the triggering factors have not been fully elucidated. Microvesicles carrying mitochondrial content (mitoMVs) have been implicated in several diseases and shown to induce endothelial activation.

AIM

To explore whether mitoMVs constitute a subset of MVs isolated from plasma of patients with sepsis and contribute to endothelial activation.

METHODS

MVs were isolated from human plasma and characterized by confocal microscopy and flow cytometry. Proinflammatory cytokines, including interleukin (IL)-6, IL-8 and tumour necrosis factor (TNF)-α, and soluble vascular cell adhesion molecule (sVCAM)-1 were detected by ELISA. Human umbilical vein endothelial cells (HUVECs) were stimulated with the circulating MVs to evaluate their effect on endothelial activation.

RESULTS

MitoMVs were observed in plasma from patients with sepsis. Compared with those in healthy controls, expression of MVs, mitoMVs, proinflammatory cytokines and sVCAM-1 was increased. The number of mitoMVs was positively associated with TNF-α and sVCAM-1. In vitro, compared with MVs isolated from the plasma of healthy controls, MVs isolated from the plasma of patients with sepsis induced expression of OAS2, RSAD2, and CXCL10 in HUVECs. MitoMVs were taken up by HUVECs, and sonication of MVs significantly reduced the uptake of mitoMVs by HUVECs and expression of the above three type I IFN-dependent genes.

CONCLUSION

MitoMVs are increased in the plasma of patients with sepsis, which induces elevated expression of type I IFN-dependent genes. This suggests that circulating mitoMVs activate the type I IFN signalling pathway in endothelial cells and lead to endothelial activation.

Reliability of pathophysiological markers reflective of exercise-induced gastrointestinal syndrome (EIGS) in response to 2-h high-intensity interval exercise: A comprehensive methodological efficacy exploration

The study aimed to determine the test-retest reliability of exercise-induced gastrointestinal syndrome (EIGS) biomarkers, and assess the association of pre-exercise short chain fatty acid (SCFA) concentration with these biomarkers in response to prolonged strenuous exercise. Thirty-four participants completed 2 h of high-intensity interval training (HIIT) on two separate occasions with at least 5-days washout. Blood samples were collected pre- and post-exercise, and analysed for biomarkers associated with EIGS [i.e., cortisol, intestinal fatty-acid binding protein (I-FABP), sCD14, lipopolysaccharide binding protein (LBP), leukocyte counts, in-vitro neutrophil function, and systemic inflammatory cytokine profile]. Fecal samples were collected pre-exercise on both occasions. In plasma and fecal samples, bacterial DNA concentration was determined by fluorometer quantification, microbial taxonomy by 16S rRNA amplicon sequencing, and SCFA concentration by gas-chromatography. In response to exercise, 2 h of HIIT modestly perturbed biomarkers indicative of EIGS, including inducing bacteremia (i.e., quantity and diversity). Reliability analysis using comparative tests, Cohen's d, two-tailed correlation, and intraclass correlation coefficient (ICC) of resting biomarkers presented good-to-excellent for IL-1ra (r = 0.710, ICC = 0.92), IL-10 (r = 0.665, ICC = 0.73), cortisol (r = 0.870, ICC = 0.87), and LBP (r = 0.813, ICC = 0.76); moderate for total (r = 0.839, ICC = 0.44) and per cell (r = 0.749, ICC = 0.54) bacterially-stimulated elastase release, IL-1β (r = 0.625, ICC = 0.64), TNF-α (r = 0.523, ICC = 0.56), I-FABP (r = 0.411, ICC = 0.21), and sCD14 (r = 0.409, ICC = 0.38), plus fecal bacterial α-diversity; and poor for leukocyte (r = 0.327, ICC = 0.33) and neutrophil (r = 0.352, ICC = 0.32) counts. In addition, a medium negative correlation was observed between plasma butyrate and I-FABP (r = -0.390). The current data suggest a suite of biomarkers should be used to determine the incidence and severity of EIGS. Moreover, determination of plasma and/or fecal SCFA may provide some insight into the mechanistic aspects of EIGS instigation and magnitude in response to exercise.

Indirect Method for Estimation of Reference Intervals of Inflammatory Markers

Background

The direct method for reference interval (RI) estimating is limited due to the requirement of resources, difficulties in defining a non-diseased population, or ethical problems in obtaining samples. We estimated the RI for inflammatory biomarkers using an indirect method (RII).

Methods

C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and presepsin (PSEP) data of patients visiting a single hospital were retrieved from April 2009 to April 2021. Right-skewed data were transformed using the Box-Cox transformation method. A mixed population of non-diseased and diseased distributions was assumed, followed by latent profile analysis for the two classes. The intersection point of the distribution curve was estimated as the RI. The influence of measurement size was evaluated as the ratio of abnormal values and adjustment (n×bandwidth) of the distribution curve.

Results

The RIs estimated by the proposed RII method (existing method) were as follows: CRP, 0-4.1 (0-4.7) mg/L; ESR, 0-10.2 (0-15) mm/hr and PSEP, 0-411 (0-300) pg/mL. Measurement sizes ≥2,500 showed stable results. An abnormal-to-normal value ratio of 0.5 showed the most accurate result for CRP. Adjustment values ≤5 or >5 were applicable for a measurement size <25,000 or ≥25,000, respectively.

Conclusions

The proposed RII method could provide additional information for RI verification or estimation with some limitations.

Novel biomarker panel for the diagnosis and prognosis assessment of sepsis based on machine learning

Background: The authors investigated a panel of novel biomarkers for diagnosis and prognosis assessment of sepsis using machine learning (ML) methods. Methods: Hematological parameters, liver function indices and inflammatory marker levels of 332 subjects were retrospectively analyzed. Results: The authors constructed sepsis diagnosis models and identified the random forest (RF) model to be the most optimal. Compared with PCT (procalcitonin) and CRP (C-reactive protein), the RF model identified sepsis patients at an earlier stage. The sepsis group had a mortality rate of 36.3%, and the RF model had greater predictive ability for the 30-day mortality risk of sepsis patients. Conclusion: The RF model facilitated the identification of sepsis patients and showed greater accuracy in predicting the 30-day mortality risk of sepsis patients.

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.

Assessment of Exercise-Associated Gastrointestinal Perturbations in Research and Practical Settings: Methodological Concerns and Recommendations for Best Practice

Strenuous exercise is synonymous with disturbing gastrointestinal integrity and function, subsequently prompting systemic immune responses and exercise-associated gastrointestinal symptoms, a condition established as "exercise-induced gastrointestinal syndrome." When exercise stress and aligned exacerbation factors (i.e., extrinsic and intrinsic) are of substantial magnitude, these exercise-associated gastrointestinal perturbations can cause performance decrements and health implications of clinical significance. This potentially explains the exponential growth in exploratory, mechanistic, and interventional research in exercise gastroenterology to understand, accurately measure and interpret, and prevent or attenuate the performance debilitating and health consequences of exercise-induced gastrointestinal syndrome. Considering the recent advancement in exercise gastroenterology research, it has been highlighted that published literature in the area is consistently affected by substantial experimental limitations that may affect the accuracy of translating study outcomes into practical application/s and/or design of future research. This perspective methodological review attempts to highlight these concerns and provides guidance to improve the validity, reliability, and robustness of the next generation of exercise gastroenterology research. These methodological concerns include participant screening and description, exertional and exertional heat stress load, dietary control, hydration status, food and fluid provisions, circadian variation, biological sex differences, comprehensive assessment of established markers of exercise-induced gastrointestinal syndrome, validity of gastrointestinal symptoms assessment tool, and data reporting and presentation. Standardized experimental procedures are needed for the accurate interpretation of research findings, avoiding misinterpreted (e.g., pathological relevance of response magnitude) and overstated conclusions (e.g., clinical and practical relevance of intervention research outcomes), which will support more accurate translation into safe practice guidelines.

Performance evaluation of presepsin using a Sysmex HISCL ‐5000 analyzer and determination of reference interval

Background

Analytical evaluation of newly developed presepsin by a Sysmex HISCL‐5000 (Sysmex, Japan) automated immune analyzer was performed.

Methods

For evaluation, sepsis patient samples were collected before treatment in an emergency department. Precision, linearity, limit of blank/limit of detection, method comparisons, and reference intervals were evaluated. Method comparisons were performed using a PATHFAST immune analyzer (LSI Medience Corporation, Japan).

Results

Precision using a 20x2x2 protocol for low (306 pg/mL) and high (1031 pg/mL) levels resulted in within‐laboratory standard deviation (95% confidence interval [CI]) and coefficient of variation (CV) %, which were as follows: 15.3 (13.1–18.7), 5.5% and 47.7, (40.5–58.1), 6.4%, respectively. Linearity using patient samples and calibrators were measured from 201 to 16,177 and 188 to 30,000 pg/mL, respectively. The regression equation was y = −23.2 + 1.008x (SE = 162.4) for low levels and y = 779.9 + 1.006x (SE = 668) for high levels. Method comparison by Passing–Bablock analysis was as follows: y = −209.77 + 1.047x (S_yx = 335.3). The correlation coefficient (95% CI) was 0.869 (0.772–0.927) with statistical significance (p < 0.001). Reference intervals from 120 normal healthy subjects showed that 300 pg/mL was the cut off. Presepsin tended to show a higher value at higher ages and in males. Presepsin showed correlation with some parameters, and the correlation coefficient (p value) were as follows: hematocrit, 0.198 (0.03); eGFR (CKD‐EPI), −0.240 (0.0129); MDRD‐eGFR, −0.194 (0.048), respectively.

Conclusion

Presepsin measurement by HISCL‐5000 showed reliable performance. Further clinical studies are required for the diagnosis and prognosis of sepsis.

The Association between Inflammatory Biomarkers and Cardiovascular Autonomic Dysfunction after Bacterial Infection

Heart rate variability (HRV) is a known measure of cardiac autonomic function. A cardiovascular autonomic dysfunction (CAD), measured as changes in HRV, is usually presented after an infectious process. The aim of the present study is to assess the association between serum inflammatory markers and CAD. For this purpose, 50 volunteers (13 of them recovering from an infection) were recruited and followed-up for 6 weeks. Their serum inflammatory biomarkers (CRP, IL1, IL4, IL6, IL10, and TNFalpha) were quantified throughout those weeks, along with their HRV resting, in response to the Valsalva maneuver, metronome breathing, standing and sustained handgrip. The correlation of within-subject changes in both HRV and inflammatory biomarkers was assessed to evaluate the concurrent changes. An inverse within-subject correlation was found between CRP and HRV in response to the Valsalva maneuver (rho (95% CI): −0.517 (−0.877 to −0.001); p = 0.032) and HRV standing (rho (95% CI): −0.490 (−0.943 to −0.036); p = 0.034). At the beginning, increased values of CRP are found along with reduced levels of HRV. Then, the CRP was reduced, accompanied by an improvement (increase) in HRV. These results suggest that CRP is a potential marker of CAD. Whether it is the cause, the consequence or a risk indicator non-causally associated is still to be determined.

Efficiency of Monocyte/High-Density Lipoprotein Cholesterol Ratio Combined With Neutrophil/Lymphocyte Ratio in Predicting 28-Day Mortality in Patients With Sepsis

Background: Sepsis can cause unpredictable harm, and early identification of risk for mortality may be conducive to clinical diagnosis. The present study proposes to assess the efficacy of the monocyte/high-density lipoprotein cholesterol ratio (MHR) combined with the neutrophil/lymphocyte ratio (NLR) on the day of admission in predictive efficacy in the 28-day mortality risk in critical patients with sepsis.

Material and Methods: We administered observational and retrospective cohort research from a single center. The correlation of the clinical variables, together with the system severity scores of APACHE II and SOFA, are displayed by correlation analysis, and a Cox regression model could be performed to screen the independent risk factors and estimate the capacity of multiple markers in predicting 28-day mortality. The receiver operating characteristic (ROC) curve served as an applied method to output cutoff values for the diagnosis and prognostic risk, and the area under the ROC curve and net reclassification improvement index (NRI), as well as integrated discrimination improvement index (IDI) were employed to assess the feasibility of multiple parameters for predictive value in 28-day mortality of septic patients.

Results: The study enrolled 274 eligible patients with sepsis. The correlation analysis indicated NLR and MHR were related to the sepsis severity. A multivariate Cox regression analysis indicated that NLR together with MHR displayed a close relation to death rate after adjusting for other potential confounders (NLR, HR = 1.404 [95% CI 1.170–1.684], P < 0.001; MHR, HR = 1.217 [95% CI 1.112–1.331], P < 0.001). The AUC of NLR, MHR, NLR_MHR was 0.827, 0.876, and 0.934, respectively. The addition on the biomarker NLR_MHR to the prediction model improved IDI by 18.5% and NRI by 37.8%.

Conclusions: Our findings suggest that NLR and MHR trend to an elevated level in non-surviving patients with sepsis. Evaluation of NLR_MHR, an independent risk factor for increased mortality, might improve the predictive efficacy for 28-day mortality risk in septic patients.

Prognostic Role of Serum Procalcitonin Measurement in Adult Patients Admitted to the Emergency Department with Fever

Background and Objectives. Fever is one of the most common presenting complaints in the Emergency Department (ED). This study aimed at evaluating the prognostic role of serum Procalcitonin (PCT) measurement among adult patients admitted to the ED with fever. Materials and Methods. This is a retrospective cross-sectional study including all consecutive patients admitted to ED with fever and subsequently hospitalized in a period of six-year (January 2014 to December 2019). Inclusion criteria were age > 18 years, fever (T ≥ 38 °C) or chills within 24 h from presentation to the ED as the main symptom, and availability of a PCT determination obtained <24 h since ED access. The primary endpoint was overall in-hospital mortality. Results. Overall, 6595 patients were included in the study cohort (3734 males, 55.6%), with a median age of 71 [58-81] years. Among these, based on clinical findings and quick sequential organ failure assessment (qSOFA), 422 were considered septic (36.2% deceased), and 6173 patients non-septic (16.2% deceased). After correction for baseline covariates, a PCT > 0.5 ng/mL was an independent risk factor for all-cause in-hospital death in both groups (HR 1.77 [1.27-2.48], and 1.80 [1.59-2.59], respectively). Conclusions. Among adult patients admitted with fever, the PCT assessment in ED could have reduced prognostic power for patients with a high suspicion of sepsis. On the other hand, it could be useful for sepsis rule-out for patients at low risk. In these latter patients, the prognostic role of PCT is higher for those with a final diagnosis of bloodstream infection.

Roflumilast as a Potential Therapeutic Agent for Cecal Ligation and Puncture-Induced Septic Lung Injury

PURPOSE/AIMS

This study focused on delineating the possible effects of roflumilast (ROF), a selective phosphodiesterase 4 (PDE4) inhibitor, in rats with cecal ligation and puncture (CLP)-induced polymicrobial sepsis, and investigated whether ROF can act as a protective agent in sepsis-induced lung damage.

MATERIAL AND METHODS

Four experimental groups were organized, each comprising eight rats: Control, Sepsis, Sepsis + ROF 0.5 mgkg^-1, and Sepsis + ROF 1 mgkg^-1 groups. A polymicrobial sepsis model was induced in the rats by cecal ligation and puncture under anesthesia. Twelve hours after sepsis induction, the lungs were obtained for biochemical, molecular, and histopathological analyses.

RESULTS

In the sepsis group's lungs, the TNF-α, IL-1β, and IL-6 mRNA expression levels peaked in the sepsis group's lung tissues, and ROF significantly decreased these levels compared with the sepsis group dose-dependently. ROF also significantly decreased MDA levels in septic lungs and increased antioxidant parameters (SOD and GSH) compared with the sepsis group. Histopathological analysis results supported biochemical and molecular results.

CONCLUSIONS

ROF, a PDE4 inhibitor, suppressed the expression levels of pro-inflammatory cytokines, alleviated lung damage (probably by blocking neutrophil infiltration), and increased the capacity of the antioxidant system.

Effects of Neutrophil-to-Lymphocyte Ratio Combined With Interleukin-6 in Predicting 28-Day Mortality in Patients With Sepsis

Background

The current study aimed to evaluate the relationship between the neutrophil-to-lymphocyte ratio (NLR) combined with interleukin (IL)-6 on admission day and the 28-day mortality of septic patients.

Material and Methods

We conducted an observational retrospective study. Patients with presumed sepsis were included. We observed the correlation of studied biomarkers (NLR, IL-6, PCT, and CRP) and the severity scores (APACHE II and SOFA scores) by plotting scatter plots. The relationships of the studied biomarkers and 28-day mortality were evaluated by using Cox regression model, receiver-operating characteristic (ROC) curve, and reclassification analysis.

Results

A total of 264 patients diagnosed with sepsis were enrolled. It was revealed that IL-6 had the strongest correlation with both APACHE II and SOFA scores, followed by the NLR and PCT, and there was no obvious correlation between CRP and the illness severity. NLR and IL-6 were independent predictors of the 28-day mortality in septic patients in the Cox regression model [NLR, odds ratio 1.281 (95% CI 1.159-1.414), P < 0.001; IL-6, odds ratio 1.017 (95% CI 1.005-1.028), P=0.004]. The area under the ROC curve (AUC) of NLR, IL-6 and NLR plus IL-6 (NLR_IL-6) was 0.776, 0.849, and 0.904, respectively.

Conclusion

Our study showed that the levels of NLR and IL-6 were significantly higher in the deceased patients with sepsis. NLR and IL-6 appeared to be independent predictors of 28-day mortality in septic patients. Moreover, NLR combined with IL-6 could dramatically enhance the prediction value of 28-day mortality.

Immune gene expression networks in sepsis: A network biology approach

To study the dysregulated host immune response to infection in sepsis, gene expression profiles from the Gene Expression Omnibus (GEO) datasets GSE54514, GSE57065, GSE64456, GSE95233, GSE66099 and GSE72829 were selected. From the Kyoto Encyclopedia of Genes and Genomes (KEGG) immune system pathways, 998 unique genes were selected, and genes were classified as follows based on gene annotation from KEGG, Gene Ontology, and Reactome: adaptive immunity, antigen presentation, cytokines and chemokines, complement, hematopoiesis, innate immunity, leukocyte migration, NK cell activity, platelet activity, and signaling. After correlation matrix formation, correlation coefficient of 0.8 was selected for network generation and network analysis. Total transcriptome was analyzed for differentially expressed genes (DEG), followed by gene set enrichment analysis. The network topological structure revealed that adaptive immunity tended to form a prominent and isolated cluster in sepsis. Common genes within the cluster from the 6 datasets included CD247, CD8A, ITK, LAT, and LCK. The clustering coefficient and modularity parameters were increased in 5/6 and 4/6 datasets in the sepsis group that seemed to be associated with functional aspect of the network. GSE95233 revealed that the nonsurvivor group showed a prominent and isolated adaptive immunity cluster, whereas the survivor group had isolated complement-coagulation and platelet-related clusters. T cell receptor signaling (TCR) pathway and antigen processing and presentation pathway were down-regulated in 5/6 and 4/6 datasets, respectively. Complement and coagulation, Fc gamma, epsilon related signaling pathways were up-regulated in 5/6 datasets. Altogether, network and gene set enrichment analysis showed that adaptive-immunity-related genes along with TCR pathway were down-regulated and isolated from immune the network that seemed to be associated with unfavorable prognosis. Prominence of platelet and complement-coagulation-related genes in the immune network was associated with survival in sepsis. Complement-coagulation pathway was up-regulated in the sepsis group that was associated with favorable prognosis. Network and gene set enrichment analysis supported elucidation of sepsis pathogenesis.

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.

Presepsin as a Potential Prognostic Marker for Sepsis According to Actual Practice Guidelines

The 2016 Surviving Sepsis Campaign guidelines define sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. This study had the objective of assessing the efficacy of presepsin in the prognosis of sepsis. This was a single-center prospective study, performed in Craiova Emergency Hospital, that included 114 patients admitted in the Intensive Care Unit (ICU) department between 2018 and 2019 fulfilling the sepsis criteria. Including criteria were: age ≥ 18, sepsis diagnosed by the Sequential Organ Failure Assessment (SOFA) score of pulmonary, abdominal, urinary, surgical or unknown origin, as well as lactate levels ≥ 2 mmol/l and need of vasopressors for mean arterial pressure (MAP) ≥ 65 mmHg, despite adequate volume resuscitations for patients with septic shock. Patients younger than 18, pregnant, immunocompromised, or with terminal illnesses were excluded. Based on disease severity, patients were distributed into two study groups: sepsis-76 patients and septic shock-38 patients. As expected, SOFA score and most of its components (PaO₂/FiO₂, platelets, and Glasgow Coma Score (GCS)) were significantly modified for patients with septic shock compared to those in the sepsis group and for survivors versus non-survivors. Overall death rate was 34.2%, with a significantly higher value for patients with septic shock (55.3% vs. 23.7%, p = 0.035). Sepsis marker presepsin was significantly elevated in all patients (2047 ng/mL) and significantly increased for the septic shock patients (2538 ng/mL, p < 0.001) and non-survivors (3138 ng/mL, p < 0.001). A significant correlation was identified between the SOFA score and presepsin (r = 0.883, p < 0.001). The receiver operating characteristics (ROC)-Area Under Curve (AUC) analysis showed significant prognostic values for presepsin regarding both sepsis severity (AUC = 0.726, 95% confidence interval CI = 0.635-0.806) and mortality risk (AUC = 0.861, 95%CI = 0.784-0.919). In conclusion, under the revised definition of sepsis, presepsin could be a useful marker for prognosis of sepsis severity and mortality risk. Additional data are required to confirm the value of presepsin in sepsis prognosis.

Taurine Chloramine decreases cell viability and cytokine production in blood and spleen lymphocytes from septic rats

Taurine (Tau) is an abundant amino acid in polymorphonuclear leukocytes that react with hypochlorous acid to form taurine chloramine (TauCl) under inflammatory conditions. We investigated potential interactions between lymphocytes and TauCl in rats submitted to cecal ligation. Animals were divided into sham or CLP groups (24 or 120 h) to isolate lymphocytes from blood and spleen. Lymphocytes were cultured at a concentration of 1×106 cells/mL and activated by concanavalin A. Tau and TauCl were added at 1, 10, and 100 μM. Cells were incubated with MTT to evaluate cell viability and cytokine concentration in the supernatant was determined. TauCl decreased lymphocyte viability and altered the secretion pattern of important inflammatory mediators in non-specific-phenotype manner. The effort to a is elucidate mechanisms of immune cell (dys)function in sepsis is important to better understand the complex regulation of immune system during sepsis development, and further studies are necessary to confirm TauCl as potential target in this context.

Utility of procalcitonin in a medical intensive care unit in Croatia

AIMS

To investigate the clinical benefit of routine procalcitonin (PCT) measurement in the medical intensive care unit (ICU) of a tertiary referral hospital.

METHODS

Adult patients with suspected infections were included. White blood cells, C‑reactive protein (CRP), and PCT were measured.

RESULTS

In this study 129 patients of median age 64 years (interquartile range 39-89 years) were prospectively included. The Acute Physiology And Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores were 21 ± 14 and 7 ± 6, respectively. Intensive care unit (ICU) mortality was 22.5%. Immunocompromised patients constituted 39.5%. A significant correlation was observed between PCT and APACHE II (Spearman's rho 0.461, p < 0.01), PCT and SOFA (Spearman's rho 0.494, p < 0.01) and PCT and CRP (Spearman's rho 0.403, p < 0.01). Most patients (n = 83, 64.3%) received antibiotics before admission. No difference in PCT (1.56 ± 8 µg/L vs. 1.44 ± 13 µg/L, p = 0.6) was observed with respect to previous antibiotic therapy. Levels of PCT and CRP were significantly increased in patients with positive blood cultures, the infection caused by Gram-negative microorganism regardless of disease severity and pneumonia with complications. PCT did not differ among patients with positive vs negative urine culture (4.6 ± 16 µg/L vs. 1.76 ± 11.9 µg/L) or positive vs. negative endotracheal aspirate (1.93 ± 11.4 µg/L vs. 1.76 ± 1.11 µg/L). PCT-guided stewardship was applied in 36 patients (28%).

CONCLUSION

Increased initial PCT levels might point to the development of more severe disease caused by Gram-negative bacteria, regardless of previous antibiotic treatment. The results pertain to immunocompetent and immunocompromised patients. Implementation of PCT-guided stewardship in those patients is possible and relies on experience as well as knowledge of reference change value for a marker within the specific setting.

Nomograms Predicting the Occurrence of Sepsis in Patients following Major Hepatobiliary and Pancreatic Surgery

Purpose

Sepsis is a severe complication in patients following major hepatobiliary and pancreatic surgery. The purpose of this study was to develop and validate a nomogram based on inflammation biomarkers and clinical characteristics.

Methods

Patients who underwent major hepatobiliary and pancreatic surgery between June 2015 and April 2017 were retrospectively collected. Multivariate logistic regression was used to identify the independent risk factors associated with postoperative sepsis. A training cohort of 522 patients in an earlier period was used to develop the prediction models, and a validation cohort of 136 patients thereafter was used to validate the nomograms.

Results

Sepsis developed in 55 of 522 patients of the training cohort and 19 of 136 patients in the validation cohort, respectively. In the training cohort, one nomogram based on clinical characteristics was developed. The clinical independent risk factors for postoperative sepsis include perioperative blood transfusion, diabetes, operative time, direct bilirubin, and BMI. Another nomogram was based on both clinical characteristics and inflammation biomarkers. Multivariate regression analyses showed that previous clinical risk factors, PCT, and CRP were independent risk factors for postoperative sepsis. The last nomogram showed a good C-index of 0.844 (95% CI, 0.787-0.900) compared with the previous one of 0.777 (95% CI, 0.713-0.840). Patients with a total score more than 109 in the second model are at high risk. The positive predictive value and negative predictive value of the second nomogram were 27% and 97%, respectively.

Conclusion

The nomogram achieved good performances for predicting postoperative sepsis in patients by combining clinical and inflammation risk factors. This model can provide the early risk estimation of sepsis for patients following major hepatobiliary and pancreatic surgery.

Identification of progranulin as a novel diagnostic biomarker for early-onset sepsis in neonates

Neonatal early-onset sepsis (EOS) is associated with high morbidity and mortality. Accurate early diagnosis is crucial for prompt treatment and a better clinical outcome. We aimed to identify new biomarkers for the diagnosis of EOS. A total of 152 neonates with a risk of EOS were divided into an EOS group and a non-EOS group according to the conventional diagnostic criteria. Blood samples were collected within 0-24, 24-48, and 48-72 h after birth. Serum levels of progranulin (PGRN), interleukin (IL)-33, IL-17a, IL-23, IL-6, tumor necrosis factors α (TNF-α), interferon γ (IFN-γ), granulocyte-macrophage colony-stimulating factor (GM-CSF), procalcitonin (PCT), and C-reactive protein (CRP) were determined. PGRN levels were significantly elevated in the EOS neonates compared with the levels in the non-EOS neonates (1.53 vs. 0.77 ng/ml (median), P < 0.001), with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.76 (P < 0.001). Compared with PGRN, IL-33, IL-17a, IL-23, IL-6, PCT, and CRP showed significant (AUC > 0.70) but slightly less predictive power for EOS within the same time range. Stepwise multivariate regression analysis identified PGRN, IL-33, and PCT as independent predictors of EOS. In addition, the combined measurements of PGRN, IL-33, and PCT showed significantly higher predictive power for EOS than any of the three markers alone. PGRN showed greater efficacy for predicting EOS than the traditional markers PCT and CRP as well as other potential markers tested in this study. PGRN may serve as an effective biomarker for the early diagnosis of EOS.

Accurate MRSA identification through dual-functional aptamer and CRISPR-Cas12a assisted rolling circle amplification

Infectious diseases have become one of the most threatening global challenge with high morbidity and mortality, bringing great difficulties to clinical diagnosis and treatment. New strategy for high-specific and sensitive bacteria detection are urgently needed in facing the crisis of worldwide antibiotic resistance. Herein, a novel method through the integration of dual aptamer technology and CRISPR-Cas12a assisted rolling circle amplification (RCA) was present to obtain both accurate identification and high-sensitive detection of Methicillin-Resistant Staphylococcus Aureus (MRSA). The specificity inherited from the dual functionalized aptamers initiated bioconjugation to specifically recognize the protein targets on the surface of bacteria. Besides the target activity, the functionalized aptamer could also convert the protein recognition to nucleic acids signals. Through the integration of attached RCA and CRISPR-Cas12a assisted trans-cleavage, dual amplification of the nucleic acid signal was obtained. Based on this, we have extended the application of CRISPR-Cas12a from the nucleic acid detection to bacteria detection. As a result, the proposed method was demonstrated to be with significantly improved sensitivity towards MRSA detection. We believe that the novel integrated strategy would diversify the existing pool of bacterial detection and inspire the development of promising drug candidates in the future.

IL-10-producing regulatory B cells exhibit functional defects and play a protective role in severe endotoxic shock

Dysregulated host immune homeostasis in sepsis is life-threatening even after a successfully treated bacterial infection. Lipopolysaccharide (LPS) is an endotoxin that is a major contributor to the aberrant immune responses and endotoxic shock in gram-negative bacterial sepsis. However, the current knowledge of the role of B cells in endotoxic shock is limited. Here, we report that CD1d expression in B cells and the percentage of CD5⁺CD1d^hi regulatory B (Breg) cells decreased in a mouse model of endotoxic shock. Interestingly, IL-10 but not FasL expression in CD5⁺CD1d^hi Breg cells in response to endotoxin was dramatically reduced in severe septic shock mice, and the regulatory function of CD5⁺CD1d^hi Breg cells in vitro to control the Th1 response was also diminished. Adoptive transfer of CD5⁺CD1d^hi Breg cells from healthy WT mice but not IL-10 deficient mice downregulated the IFN-γ secretion in CD4⁺ T cells and conferred protection against severe endotoxic shock in vivo. Our findings demonstrate the change and notable therapeutic potential of IL-10-producing Breg cells in endotoxic shock.

Diagnosis and Prognosis of Sepsis Based on Use of Cytokines, Chemokines, and Growth Factors

The focus of sepsis has shifted from inflammation to organ dysfunction on the basis of a recent definition based on the sequential organ failure score (SOFA). A diagnostic and prognostic marker is necessary under this definition but is currently unknown. We enrolled 80 sepsis patients consecutively admitted to an intensive care unit through the emergency department and 80 healthy control patients who received routine health check-ups from August 2018 to January 2019. SEPSIS-3 criteria were used for the diagnosis of patients based on SOFA score ≥ 2 from the baseline along with evidence of infection. Concentrations of 28 cytokines, eight chemokines, and nine growth factors were measured on the day of diagnosis. Hierarchical cluster analysis was performed for molecules. The majority of infections were pneumonia (45% of patients) and urinary tract infections (40% of patients). Most of the measured molecules were increased in patients with sepsis. Area under receiver operating characteristic curve (AUROC) values were found to be as follows: hepatic growth factor (HGF), 0.899; interleukin-1 receptor antagonist (IL-1RA), 0.893; C-C motif ligand 5 (CCL5) 5, 0.887; C-X-C motif chemokine 10 (CXCL10), 0.851; CCL2, 0.840; and IL-6, 0.830. IL-1RA, IL-6, IL-8, IL-15, and CCL11 concentrations correlated with SOFA score with statistical significance. Prognosis multivariate analysis revealed an odds ratio of 0.968 for epidermal growth factor (EGF). Three clusters were formed, of which Clusters 2 and 3 were associated with nonsurvivors. Diagnosis of sepsis was performed using cytokines, chemokines, and growth factors. HGF revealed the highest diagnostic capability, and EGF predicted favorable prognosis among the tested molecules.

Hierarchically structured microchip for point-of-care immunoassays with dynamic detection ranges

Point-of-care (POC) medical assays provide critical information to guide clinical therapy for a broad range of medical scenarios, such as resource-poor settings and specialty departments in hospitals. Even though many types of POC assays can be done in automated devices, these POC assays typically cannot well accommodate the multiplexed detection of biomarkers where a large dynamic range is needed. Here, we report a POC assay, which is both automated and suitable for detecting multiple biomarkers with dynamic detection ranges. We call it a dynamic multiplexed immunoassay (DMI). We control the concentrations of capture antibodies and the intensity of the readout signal to dynamically modulate the detection range of immunoassays (pg mL^-1 to μg mL^-1), leading to the multiplexed detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin 6 (IL-6) simultaneously in undiluted human serum samples. The POC assay allows the rapid and accurate detection of infection in patients.

Procalcitonin as a prognostic marker for sepsis based on SEPSIS-3

BACKGROUND

The revised definition of sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection (SEPSIS-3). The objective of this study was to evaluate procalcitonin (PCT) for the diagnosis and prognosis of sepsis using SEPSIS-3.

METHODS

We enrolled 248 patients, who were admitted to the emergency department with suspected bacterial infection from June 2016 to February 2017. Definite bacterial infection was defined by proven culture results, and probable bacterial infection was based on diagnostic modalities other than culture. The sequential organ failure assessment (SOFA) score of 2 points or more from the baseline was diagnosed as sepsis. PCT was measured by the AFIAS-6 immunoassay system (Boditech Med Inc.) using whole blood. White blood cell (WBC), C-reactive protein (CRP), and erythrocyte sedimentation rate (ERS) were evaluated.

RESULTS

The final diagnosis was sepsis in 185 patients with infection of respiratory and genitourinary tract constituted 84.6%. The area under the receiver operating characteristic curve (AUROC) with 95% confidence interval (CI) was as follows: PCT, 0.682 (0.589-0.765); CRP, 0.583 (0.487-0.673); ESR, 0.540 (0.515-0.699); and WBC, 0.611 (0.455-0.633), respectively. In multivariate analysis, age, SOFA, and PCT (log scale) predicted non-survivors with an odds ratio with 95% confidence interval of 1.055 (1.008-1.105), 1.303 (1.142-1.486), and 2.004 (1.240-3.238), respectively. Among sepsis group, initial PCT was increased in non-survivor (23.2 ng/dL) compared to survivor group (8.1 ng/dL) with statistical significance (P = .005).

CONCLUSIONS

PCT could support and predict the unfavorable prognosis of sepsis based on SEPSIS-3, whereas diagnostic potential of PCT requires further evaluations.

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.

Is Interleukin-6 a better predictor of successful antibiotic therapy than procalcitonin and C-reactive protein? A single center study in critically ill adults

Background

The aim of this study was to evaluate whether Interleukin-6 (IL-6) could be a faster indicator of treatment success in adults with severe sepsis and septic shock compared to procalcitonin (PCT) and C-reactive protein (CRP).

Methods

Data from adult patients with severe sepsis and septic shock managed at the medical intensive care unit (ICU) of the University Hospital Leipzig between September 2009 and January 2012 were analyzed retrospectively. Values for CRP, PCT and IL-6 on admission as well as after 24 and 48–72 h were collected. Antibiotic therapy was defined as clinically successful if the patient survived ICU stay.

Results

A total of 328 patients with severe sepsis and septic shock with adequate data quality were included. After 48–72 h, the median IL-6 was significantly lower in survivors than in non-survivors (114.2 pg/ml vs. 746.6 pg/ml; p < 0.001), while there was no significant difference for PCT (5.6 vs. 4.9 ng/ml; p = 0.586) and CRP (158.5 mg/l vs. 172.4 mg/l; p = 0.988).

Conclusions

The results of this study suggest that IL-6 is better than PCT and CRP in predicting the treatment success in predominantly non-surgical sepsis in the first 48–72 h.

Acetic acid alleviates the inflammatory response and liver injury in septic mice by increasing the expression of TRIM40

Sepsis remains a significant health care issue in clinical practice due to its high mortality rate and healthcare cost, despite extensive efforts to better understand the pathophysiology of sepsis. The systemic inflammatory response often leads to severe liver injury, even acute liver dysfunction and failure. Acetic acid, as a type of chemical compound, has been reported to be an emerging drug for improving metabolic syndrome and inhibiting inflammation in rats and human. To verify the effects of acetic acid in protecting the liver and reducing the inflammatory response, a septic mouse model was established by cecal ligation and puncture (CLP), and then the CLP-model mice were treated with acetic acid or PBS. Following the treatment, it was determined that, in CLP-model mice, acetic acid could alleviate the inflammatory response by decreasing the expression of cytokines including interleukin-6 and tumor necrosis factor-α. Additionally, acetic acid also alleviated the liver injury, and the levels of alanine aminotransaminase, aspartate aminotransferase, Toll-like receptor (TLR)4 and nuclear factor-κB (NF-κB) were decreased. The expression of tripartite motif-containing protein (TRIM)40 was also upregulated significantly. Therefore, the authors of the current study hypothesized that acetic acid could decrease the inflammatory response by increasing the expression of TRIM40 and TRIM40 may regulate the activity of the TLR4 signaling pathway. To further illustrate the interaction between TRIM40 and the TLR4 signaling pathway, the authors collected macrophages from the peritoneal cavity by intraperitoneally administering mice with 5 ml ice-cold normal saline. Following the collection, peritoneal macrophages were treated with acetic acid, TRIM40 small interfering RNA or PBS. It was demonstrated that acetic acid upregulated the expression of TRIM40. When TRIM40 was silenced, the protective effect of acetic acid would be reversed as well. The results suggested that TRIM40 could act on and downregulate the activity of the TLR4 signaling pathway. TRIM40 is possibly the major target for acetic acid, which may function as a protective factor in septic mice.

A critical insight into the development pipeline of microfluidic immunoassay devices for the sensitive quantitation of protein biomarkers at the point of care

The latest clinical procedures for the timely and cost-effective diagnosis of chronic and acute clinical conditions, such as cardiovascular diseases, cancer, chronic respiratory diseases, diabetes or sepsis (i.e. the biggest causes of death worldwide), involve the quantitation of specific protein biomarkers released into the blood stream or other physiological fluids (e.g. urine or saliva). The clinical thresholds are usually in the femtomolar to picolomar range, and consequently the measurement of these protein biomarkers heavily relies on highly sophisticated, bulky and automated equipment in centralised pathology laboratories. The first microfluidic devices capable of measuring protein biomarkers in miniaturised immunoassays were presented nearly two decades ago and promised to revolutionise point-of-care (POC) testing by offering unmatched sensitivity and automation in a compact POC format; however, the development and adoption of microfluidic protein biomarker tests has fallen behind expectations. This review presents a detailed critical overview into the pipeline of microfluidic devices developed in the period 2005-2016 capable of measuring protein biomarkers from the pM to fM range in formats compatible with POC testing, with a particular focus on the use of affordable microfluidic materials and compact low-cost signal interrogation. The integration of these two important features (essential unique selling points for the successful microfluidic diagnostic products) has been missed in previous review articles and explain the poor adoption of microfluidic technologies in this field. Most current miniaturised devices compromise either on the affordability, compactness and/or performance of the test, making current tests unsuitable for the POC measurement of protein biomarkers. Seven core technical areas, including (i) the selected strategy for antibody immobilisation, (ii) the surface area and surface-area-to-volume ratio, (iii) surface passivation, (iv) the biological matrix interference, (v) fluid control, (vi) the signal detection modes and (vii) the affordability of the manufacturing process and detection system, were identified as the key to the effective development of a sensitive and affordable microfluidic protein biomarker POC test.

Research on the effect of cytokine concentration on the immune level and survival conditions of elderly patients with sepsis

The present study was carried out to investigate the effect of cytokine (CK) concentrations on the immune phenotype and survival conditions of elderly patients with sepsis. A total of 112 elderly patients with sepsis who were admitted to The Affiliated Hospital of Medical School, Ningbo University for treatment between June 2015 and June 2017 were enrolled as the subjects. According to each patient's condition, they were divided into the mild sepsis group (n=68) and the severe sepsis group (n=44). Additionally, a further 60 patients without sepsis who were admitted to the Intensive Care Unit (ICU) of this hospital during the same period were recruited as the control group. The levels of CK, tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-8, procalcitonin (PCT), endothelin-1 (ET-1) and IL-10 were detected, and the assessment system for immune levels was established. The levels of TNF-α, IL-6, IL-8, PCT, ET-1 and IL-10 in the serum of patients in the mild and severe sepsis groups were significantly higher than those in the control group (P<0.05), and the levels in the severe sepsis group were significantly higher than those in the mild sepsis group (P<0.05). Among the 112 sepsis patients, there were 30 mortalities (26.79%) within 30 days, of which the levels of TNF-α, IL-6, IL-8, PCT, ET-1 and IL-10 were significantly higher than those in the surviving patients (P<0.05). Between the mild and severe sepsis groups, as well as the number of mortalities and surviving patients, there were statistically significant differences when comparing the immunological phenotypes (P<0.05). These findings indicated that the levels of TNF-α, IL-6, IL-8, PCT, ET-1 and IL-10 were associated with the condition and prognosis of elderly patients with sepsis, and the assessment system for immune levels based on the levels of these indicators was conducive to the stipulation of individualized immune regulation procedure and prognostic evaluation of sepsis.

Inflammatory Mediator Profiles Differ in Sepsis Patients With and Without Bacteremia

Systemic levels of cytokines are altered during infection and sepsis. This prospective observational study aimed to investigate whether plasma levels of multiple inflammatory mediators differed between sepsis patients with and those without bacteremia during the initial phase of hospitalization. A total of 80 sepsis patients with proven bacterial infection and no immunosuppression were included in the study. Plasma samples were collected within 24 h of hospitalization, and Luminex^® analysis was performed on 35 mediators: 16 cytokines, six growth factors, four adhesion molecules, and nine matrix metalloproteases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs). Forty-two patients (52.5%) and 38 (47.5%) patients showed positive and negative blood cultures, respectively. There were significant differences in plasma levels of six soluble mediators between the two “bacteremia” and “non-bacteremia” groups, using Mann–Whitney U test (p < 0.0014): tumor necrosis factor alpha (TNFα), CCL4, E-selectin, vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), and TIMP-1. Ten soluble mediators also significantly differed in plasma levels between the two groups, with p-values ranging between 0.05 and 0.0014: interleukin (IL)-1ra, IL-10, CCL2, CCL5, CXCL8, CXCL11, hepatocyte growth factor, MMP-8, TIMP-2, and TIMP-4. VCAM-1 showed the most robust results using univariate and multivariate logistic regression. Using unsupervised hierarchical clustering, we found that TNFα, CCL4, E-selectin, VCAM-1, ICAM-1, and TIMP-1 could be used to discriminate between patients with and those without bacteremia. Patients with bacteremia were mainly clustered in two separate groups (two upper clusters, 41/42, 98%), with higher levels of the mediators. One (2%) patient with bacteremia was clustered in the lower cluster, which compromised most of the patients without bacteremia (23/38, 61%) (χ² test, p < 0.0001). Our study showed that analysis of the plasma inflammatory mediator profile could represent a potential strategy for early identification of patients with bacteremia.

Roflumilast reverses polymicrobial sepsis-induced liver damage by inhibiting inflammation in mice

Sepsis is a life-threatening syndrome accompanied by an overwhelming inflammatory response and organ dysfunction. Selective targeting of phosphodiesterase 4 (PDE4) is currently being investigated as an effective therapeutic approach for inflammation-associated diseases. Roflumilast is a selective PDE4 inhibitor, used for the treatment of severe chronic obstructive pulmonary disease in clinic. However, its role in the treatment of sepsis-induced liver damage remains unclear. In the present study, we evaluated the effects of roflumilast in mice with cecal ligation and puncture-induced sepsis, and investigated the underlying mechanism. We found that roflumilast treatment improved survival in septic mice by reducing bacterial load locally and systemically, inhibiting the expression of pro-inflammatory cytokines interleukin-6 and tumor necrosis factor alpha, and alleviating liver injury. These effects were associated with the inhibition of nuclear translocation of nuclear factor-kappa B (NF-κB), as well as degradation of NF-κB inhibitory protein alpha. The phosphorylation of p38 mitogen-activated protein kinase (MAPK) was also markedly inhibited by roflumilast. Moreover, roflumilast significantly suppressed the activation of signal transducer and activator of transcription 3 (STAT3) and its upstream Janus kinase 1 and Janus kinase 2. Taken together, these results indicate that roflumilast prevents polymicrobial sepsis likely by suppressing NF-κB, p38 MAPK, and STAT3 pathways.

Biomarkers for diagnosis of sepsis in patients with systemic inflammatory response syndrome: a systematic review and meta-analysis

Background

Sepsis is one of the most common diseases that seriously threaten human health. Although a large number of markers related to sepsis have been reported in the last two decades, the diagnostic accuracy of these biomarkers remains unclear due to the lack of similar baselines among studies. Therefore, we conducted a large systematic review and meta-analysis to evaluate the diagnostic value of biomarkers from studies that included non-infectious systemic inflammatory response syndrome patients as a control group.

Methods

We searched Medline, Embase and the reference lists of identified studies beginning in April 2014. The last retrieval was updated in September 2016.

Results

Ultimately, 86 articles fulfilled the inclusion criteria. Sixty biomarkers and 10,438 subjects entered the final analysis. The areas under the receiver operating characteristic curves for the 7 most common biomarkers, including procalcitonin, C-reactive protein, interleukin 6, soluble triggering receptor expressed on myeloid cells-1, presepsin, lipopolysaccharide binding protein and CD64, were 0.85, 0.77, 0.79, 0.85, 0.88, 0.71 and 0.96, respectively. The remaining 53 biomarkers exhibited obvious variances in diagnostic value and methodological quality.

Conclusions

Although some biomarkers displayed moderate or above moderate diagnostic value for sepsis, the limitations of the methodological quality and sample size may weaken these findings. Currently, we still lack an ideal biomarker to aid in the diagnosis of sepsis. In the future, biomarkers with better diagnostic value as well as a combined diagnosis using multiple biomarkers are expected to solve the challenge of the diagnosis of sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-3591-5) contains supplementary material, which is available to authorized users.

High cut-off hemofiltration versus standard hemofiltration: effect on plasma cytokines

PURPOSE

To study the effects of continuous veno-venous hemofiltration (CVVH) with high cut-off filters (CVVH-HCO) on plasma cytokine levels, sieving coefficient and clearance compared to CVVH using standard filters (CVVH-Std) in a nested cohort within a double-blind randomized controlled trial in severe acute kidney injury (AKI) patients.

METHODS

We measured plasma and post-filter levels of IL-6, TNF-alpha, IL-8, IL-1 beta, RANTES, IL-10, IFN-gamma and IFN-alpha in both study groups. We also measured cytokine levels in the ultrafiltrate and calculated sieving coefficients and clearances.

RESULTS

By 72 hours of treatment, IL-6 had decreased during both treatments (p = 0.009 and 0.005 respectively). In contrast, IL-10 had decreased with CVVH-Std (p = 0.03) but not CVVH-HCO (p = 0.135). None of the other cytokines showed changes over time. There were also no significant between group differences in plasma levels for each cytokine over the 72-hour treatment period. For all cytokines combined, however, the median sieving coefficient was higher for CVVH-HCO (0.31 vs. 0.16; p = 0.042) as was the mass removal rate by ultrafiltration (p = 0.027). While overall combined cytokine levels had fallen to 62.2% of baseline at 72 hours for CVVH-HCO (p&lt;0.0001) and to 75.9% of baseline with CVVH-Std (p = 0.008) there were no between group differences.

CONCLUSIONS

CVVH-HCO achieved greater combined sieving coefficient and mass removal rate by ultrafiltration for a group of key cytokines than CVVH-Std. However, this effect did not differentially lower their plasma level over the first 72 hours. Our study does not support the use of CVVH-HCO to lower cytokines in critically ill patients with AKI.

Interleukin 35: A novel candidate biomarker to diagnose early onset sepsis in neonates

BACKGROUND

Early onset sepsis (EOS) remains a major cause of morbidity and mortality in newborns; however, current diagnostic tools are inadequate. We evaluated the accuracy of a novel cytokine, interleukin (IL)-35, for the diagnosis of EOS in comparison with other infection markers.

METHODS

One hundred fifty-seven neonates with suspected sepsis in the first 3days of life were enrolled in this perspective study. All enrolled patients were divided into infected group and unlikely infected group according to clinical data. IL-35, C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and blood culture were measured once the suspected EOS was documented.

RESULTS

Serum concentration of IL-35 was increased significantly in the infected group compared with the unlikely infected group (median 36.4 versus 27.1pg/ml, respectively, p<0.001). The area under receiver-operating characteristic (ROC) curve were 0.756 for IL-35, 0.713 for PCT (age-adjusted), 0.670 for CRP, and 0.619 for WBC. With a cut-off value of 31.7pg/ml, the diagnostic sensitivity and specificity of IL-35 were 78.48% and 66.67%, respectively. Moreover, unlike PCT concentration, IL-35 concentration did not fluctuate in neonates who were unlikely to be infected (p=0.885).

CONCLUSION

The diagnostic performance of IL-35 was superior to that of PCT and other commonly used markers, suggesting that IL-35 may be a valuable tool for EOS diagnosis.

Role of interleukin-6 to differentiate sepsis from non-infectious systemic inflammatory response syndrome

Differentiating between sepsis and non-infectious systemic inflammatory response syndrome (SIRS) poses a great challenge. Several potential bloodstream biomarkers including Interleukin 6 (IL-6) have been investigated for their ability to diagnose sepsis. We conducted the present meta-analysis to evaluate the diagnostic quality of IL-6 in differentiating sepsis from non-infectious SIRS in adults. We also compared its accuracy with procalcitonin (PCT) and C-reactive protein (CRP). PubMed and EMBASE were systematically searched for studies published up to January 18, 2016. Twenty articles containing 22 studies and 2680 critically ill patients were included, of which, 21 studies also involved PCT and 14 involved CRP. Quantitative synthesis of studies showed that the pooled sensitivity/specificity of IL-6 and PCT were 0.68/0.73 and 0.78/0.67. The area under the curve (AUC) of IL-6, PCT and CPR for diagnosis of sepsis was 0.80, 0.83, and 0.71, respectively. This meta-analysis provides evidence that the IL-6 test has moderate diagnostic performance in differentiating sepsis from non-infectious SIRS in adults. IL-6 and PCT test has similar diagnostic value but higher than CRP. Considering its relatively high specificity, we recommend the use of IL-6 as a diagnostic aid to confirm infection rather than exclude infection in patients with SIRS.