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

Self-referenced Digital Spectral Chromatic Local Surface Plasmon Resonance in Ultrasensitive Severe Sepsis Interleukin-6 Detection

Clinical monitoring of cytokines, such as interleukin-6 (IL-6), enables a timely diagnosis and can significantly improve patient prognosis. In this study, we developed a rapid, label-free, ultrasensitive, and low matrix-effect method called chromatic digital nanoplasmon-metry (cDiNM) to detect IL-6 in human blood plasma. Utilizing a multiple filter configuration, two nonadjacent specific transmission wavelength bands are extracted. One is centered within the full-width-at-half-maximum (fwhm) range where the local surface plasmon resonance (LSPR) response of the 80 nm gold nanoparticles (AuNPs) is strongest, while the other band is narrowed and blue-shifted from the peak to a region with minor intensity change. Scattering images of AuNPs passing through these two bands are then captured simultaneously and independently via the red and green channels of a color scientific complementary metal-oxide-semiconductor (sCMOS) camera. This configuration allows every AuNPs' spectral chromatic image contrast to be a self-referenced subtractive analysis LSPR and facilitates evaluation of their changes induced by the IL-6 binding across numerous individual AuNPs. This method achieves IL-6 detection in blood plasma within 45 min, requiring only 0.5 mL of a 10-fold diluted, label-free sample, with a limit of detection and quantification (LOD and LOQ) of less than 19.2 and 87.8 fg/mL, respectively, and a recovery rate of 96%. In summary, cDiNM provides rapid and accurate IL-6 monitoring with promising potential for clinical application in sepsis patient care.

Intralesional injection of CpG ODNs complexed with glatiramer acetate mitigates systemic cytokine toxicities and synergistically advances checkpoint blockade efficacy

PD-L1/PD-1 checkpoint inhibitors (CPIs) are mainstream agents for cancer immunotherapy, but the prognosis is unsatisfactory in solid tumor patients lacking preexisting T-cell reactivity. Adjunct therapy strategies including the intratumoral administration of immunostimulants aim to address this limitation. CpG oligodeoxynucleotides (ODNs), TLR9 agonists that can potentiate adaptive immunity, have been widely investigated to tackle PD-L1/PD-1 resistance, but clinical success has been hindered by inconsistent efficacy and immune-related toxicities caused by systemic exposure. Here, we utilized glatiramer acetate (GA), the FDA-approved, lysine-rich polypeptides to complex CpG into polycationic nanoparticles (R4B) and investigated the safety and antitumor efficacy of CpG ODNs in the murine CT26 colorectal carcinoma model. In a maximum tolerated dose study, repetitive R4B treatment displayed comparable antitumor efficacy to CpG alone treatment within a dose range from 15 µg to 150 µg while significantly attenuating systemic proinflammatory cytokine IL-6 release. A pharmacokinetic and biodistribution analysis confirmed that R4B localized and gradually released CpG around the lesions within 96 h while 'naked' CpG quickly diffused from the injection site. Genome-wide transcriptome analysis validated that R4B treatment activated prominent TLR9-driven immune system responses in both lesions and spleens. In a CT26 multiple tumor model, intratumoral administration of R4B generated systemic immune efficacy, evidenced by an abscopal effect on untreated tumors. Notably, R4B treatment accomplished these effects with mitigated systemic proinflammatory cytokines when compared with CpG alone. We further discovered that combining R4B with anti-PD-1 treatment led to the most pronounced effects on tumor growth and longest benefits to survival time. Our investigation into possible mechanisms underlying this phenomenon included increased recruitment of cytotoxic CD8+ T cells and natural killer (NK) cells to the tumor microenvironments and the reversal of PD-L1/PD-1 axis inhibition. In summary, these results warrant further investigation for safely improving clinical responses in CPI-resistant solid tumor patients with localized CpG ODN therapy.

Interleukin-6 in Sepsis-Promising but Yet to Be Proven

How to cite this article: Sinha S. Interleukin-6 in Sepsis-Promising but Yet to Be Proven. Indian J Crit Care Med 2024;28(7):629-631.

Review of the Predictive Value of Biomarkers in Sepsis Mortality

Sepsis is a leading cause of mortality among severely ill individuals, primarily due to its potential to induce fatal organ dysfunction. For clinicians, it is vital to have appropriate indicators, including the physiological status and personal experiences of patients with sepsis, to monitor the condition and assess prognosis. This approach aids in preventing the worsening of the illness and reduces mortality. Recent guidelines for sepsis focus on improving patient outcomes through early detection and timely treatment. Nonetheless, identifying severe cases and predicting their prognoses remain challenging. In recent years, there has been considerable interest in utilising the C-reactive protein (CRP)/albumin ratio (CAR) to evaluate the condition and forecast the prognosis of patients with sepsis. This research concentrates on the significance of CAR in the pathological process of sepsis, its association with prognosis, and the latest developments in employing procalcitonin, lactic acid, CRP, and other potential biomarkers. The CAR, with its predictive value for sepsis prognosis and mortality, is increasingly used as a clinical biochemical marker in diagnosing and monitoring patients with sepsis.

Integrated Analysis Identified TGFBI as a Biomarker of Disease Severity and Prognosis Correlated with Immune Infiltrates in Patients with Sepsis

Background

Sepsis is a major contributor to morbidity and mortality among hospitalized patients. This study aims to identify markers associated with the severity and prognosis of sepsis, providing new approaches for its management and treatment.

Methods

Data were mined from the Gene Expression Omnibus (GEO) databases and were analyzed by multiple statistical methods like the Spearman correlation coefficient, Kaplan-Meier analysis, Cox regression analysis, and functional enrichment analysis. Candidate indicator' associations with immune infiltration and roles in sepsis development were evaluated. Additionally, we employed techniques such as flow cytometry and neutral red staining to evaluate its impact on macrophage functions like polarization and phagocytosis.

Results

Twenty-eight genes were identified as being closely linked to the severity of sepsis, among which transforming growth factor beta induced (TGFBI) emerged as a distinct marker for predicting clinical outcomes. Notably, reductions in TGFBI expression during sepsis correlate with poor prognosis and rapid disease progression. Elevated expression of TGFBI has been observed to mitigate abnormalities in sepsis-related immune cell infiltration that are critical to the pathogenesis and prognosis of the disease, including but not limited to type 17 T helper cells and activated CD8 T cells. Moreover, the protein-protein interaction network revealed the top ten genes that interact with TGFBI, showing significant involvement in the regulation of the actin cytoskeleton, extracellular matrix-receptor interactions, and phagosomes. These are pivotal elements in the formation of phagocytic cups by macrophages, squaring the findings of the Human Protein Atlas. Additionally, we discovered that TGFBI expression was significantly higher in M2-like macrophages, and its upregulation was found to inhibit lipopolysaccharide-induced polarization and phagocytosis in M1-like macrophages, thereby playing a role in preventing the onset of inflammation.

Conclusion

TGFBI warrants additional exploration as a promising biomarker for assessing illness severity and prognosis in patients with sepsis, considering its significant association with immunological and inflammatory responses in this condition.

Diagnostic accuracy of interleukin-6 in multiple diseases: An umbrella review of meta-analyses

Objective

This review aims to conduct a comprehensive study of the diagnostic accuracy of interleukin-6 (IL-6) for multiple diseases by utilizing existing systematic reviews and meta-analyses.

Methods

We performed a thorough search of Embase, Web of Science, PubMed, and Cochrane Database of Systematic Reviews up to April 2023 to gather meta-analyses that investigate the diagnostic accuracy of IL-6. To assess the methodological quality of the studies, we employed the Assessing the Methodological Quality of Systematic Reviews-2 and Grading of Recommendations, Assessment, Development and Evaluation criteria.

Results

We included 34 meta-analyses out of the 3024 articles retrieved from the search. These meta-analyses covered 9 categories of diseases of the International Classification of Diseases-11. Studies rated as "Critically Low" or "Very Low" in the quality assessment process were excluded, resulting in a total of 6 meta-analyses that encompassed sepsis, colorectal cancer, tuberculous pleural effusion (TPE), endometriosis, among others. Among these diseases, IL-6 demonstrated a relatively high diagnostic potential in accurately identifying TPE and endometriosis.

Conclusions

IL-6 exhibited favorable diagnostic accuracy across multiple diseases, suggesting its potential as a reliable diagnostic biomarker in the near future. Substantial evidence supported its high diagnostic accuracy, particularly in the cases of TPE and endometriosis.

The monocyte-derived cytokine response in whole blood from preterm newborns against sepsis-related bacteria is similar to term newborns and adults

Introduction

Sepsis is characterized by a dysregulated innate immune response. It is a leading cause of morbidity and mortality in newborns, in particular for newborns that are born premature. Although previous literature indicate that the pro-inflammatory response may be impaired in preterm newborns, serum levels of monocyte-derived cytokines, such as TNF-α and IL-6, vary highly between newborns and can reach adult-like concentrations during sepsis. These contradictory observations and the severe consequences of neonatal sepsis in preterm newborns highlight the need for a better understanding of the pro-inflammatory cytokine response of preterm newborns to improve sepsis-related outcomes.

Methods and results

Using an in vitro model with multiple read outs at the transcriptional and protein level, we consistently showed that the monocyte-derived cytokine response induced by sepsis-related bacteria is comparable between preterm newborns, term newborns and adults. We substantiated these findings by employing recombinant Toll-like receptor (TLR) ligands and showed that the activation of specific immune pathways, including the expression of TLRs, is also similar between preterm newborns, term newborns and adults. Importantly, we showed that at birth the production of TNF-α and IL-6 is highly variable between individuals and independent of gestational age.

Discussion

These findings indicate that preterm newborns are equally capable of mounting a pro-inflammatory response against a broad range of bacterial pathogens that is comparable to term newborns and adults. Our results provide a better understanding of the pro-inflammatory response by preterm newborns and could guide the development of interventions that specifically modulate the pro-inflammatory response during sepsis in preterm newborns.

Clinical significance of inflammatory markers for evaluating disease severity of mixed-pathogen bloodstream infections of both Enterococcus spp. and Candida spp

Objective

In recent decades, there has been a notable increase in the morbidity and mortality rates linked to bacteremia and candidemia. This study aimed to investigate the clinical significance of inflammatory markers in assessing the disease severity in critically ill patients suffering from mixed-bloodstream infections (BSIs) due to Enterococcus spp. and Candida spp.

Methods

In this retrospective research, patients diagnosed with BSIs who were admitted to the intensive care unit (ICU) during the period of January 2019 to December 2022 were analyzed. The patients were divided into two groups: a mixed-pathogen BSI group with both Enterococcus spp. and Candida spp., and a single-pathogen BSI group with only Enterococcus spp. The study examined the differences in inflammatory marker levels and disease severity, including Acute Physiology and Chronic Health Evaluation (APACHE) II scores, duration of ICU stay, and 30-day mortality, between the two groups. Furthermore, we sought to scrutinize the potential associations among these aforementioned parameters.

Results

The neutrophil-to-lymphocyte ratios (NLRs) and levels of plasma C-reactive protein (CRP), interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) in the mixed-pathogen BSI group were higher than those in the single-pathogen BSI group. Spearman's rank correlation analysis showed that NLRs and plasma CRP and IL-6 levels were positively correlated with disease severity in the mixed-pathogen BSI group. Further, the levels of plasma IL-8 and TNF-α were also positively correlated with ICU stay duration and 30-day mortality. In multivariate analysis, plasma CRP and IL-6 levels were independently associated with 30-day mortality.

Conclusion

Mixed-pathogen BSIs caused by Enterococcus spp. and Candida spp. may give rise to increased NLRs and plasma CRP, IL-6, IL-8, and TNF-α levels in comparison to BSI caused by Enterococcus spp. only, thus leading to elevated disease severity in critically ill patients.

Low levels of small HDL particles predict but do not influence risk of sepsis

BACKGROUND

Low levels of high-density lipoprotein (HDL) cholesterol have been associated with higher rates and severity of infection. Alterations in inflammatory mediators and infection are associated with alterations in HDL cholesterol. It is unknown whether the association between HDL and infection is present for all particle sizes, and whether the observed associations are confounded by IL-6 signalling.

METHODS

In the UK Biobank, ~ 270,000 individuals have data on HDL subclasses derived from nuclear magnetic resonance analysis. We estimated the association of particle count of total HDL and HDL subclasses (small, medium, large, and extra-large HDL) with sepsis, sepsis-related death, and critical care admission in a Cox regression model. We subsequently utilised genetic data from UK Biobank and FinnGen to perform Mendelian randomisation (MR) of each HDL subclass and sepsis to test for a causal relationship. Finally, we explored the role of IL-6 signalling as a potential causal driver of changes in HDL subclasses.

RESULTS

In observational analyses, higher particle count of small HDL was associated with protection from sepsis (Hazard ratio, HR 0.80; 95% CI 0.74-0.86, p = 4 × 10-9 comparing Quartile 4, highest quartile of HDL to Quartile 1, lowest quartile of HDL), sepsis-related death (HR 0.80; 95% CI 0.74-0.86, p = 2 × 10-4), and critical care admission with sepsis (HR 0.72 95% CI 0.60-0.85, p = 2 × 10-4). Parallel associations with other HDL subclasses were likely driven by changes in the small HDL compartment. MR analyses did not strongly support causality of small HDL particle count on sepsis incidence (Odds ratio, OR 0.98; 95% CI 0.89-1.07, p = 0.6) or death (OR 0.94, 95% CI 0.75-1.17, p = 0.56), although the estimate on critical care admission with sepsis supported protection (OR 0.73, 95% CI 0.57-0.95, p = 0.02). Bidirectional MR analyses suggested that increased IL-6 signalling was associated with reductions in both small (beta on small HDL particle count - 0.16, 95% CI - 0.10 to - 0.21 per natural log change in SD-scaled CRP, p = 9 × 10-8).and total HDL particle count (beta - 0.13, 95% CI - 0.09 to - 0.17, p = 7 × 10-10), but that the reverse effect of HDL on IL-6 signalling was largely null.

CONCLUSIONS

Low number of small HDL particles are associated with increased hazard of sepsis, sepsis-related death, and sepsis-related critical care admission. However, genetic analyses did not strongly support this as causal. Instead, we demonstrate that increased IL-6 signalling, which is known to alter infection risk, could confound associations with reduced HDL particle count, and suggest this may explain part of the observed association between (small) HDL particle count and sepsis.

Towards a point-of-care test to cover atto-femto and pico-nano molar concentration ranges in interleukin 6 detection exploiting PMMA-based plasmonic biosensor chips

Point-of-Care tests based on biomarkers, useful to monitor acute and chronic inflammations, are required for advances in medicine. In this scope, a key role is played by pro-inflammatory cytokines, of which interleukin 6 (IL-6) is generally thought as one of the most relevant. To use IL-6 in real scenarios, detection in ultra-low concentration ranges is required. In this work, two IL-6 biosensors are obtained by exploiting the combination of the same antibody self-assembled monolayer with two different plasmonic probes. This approach has demonstrated, via experimental results, that two different IL-6 concentration ranges can be explored. More specifically, IL-6 in an atto-femto molar range can be detected via polymer-based nanoplasmonic chips. On the other hand, a pico-nano molar range is obtained by a surface plasmon resonance platform in plastic optical fibers. As a proof of concept, the detection of IL-6 at the femto molar range has been obtained in Saliva and Serum. The results show that the proposed sensing approach could be useful in developing Point-of-Care devices based on a general setup with the capability to exploit both the plasmonic biosensor chips to monitor the IL-6 in the concentration range of interest, to provide an important support for the diagnosis and monitoring of oral and systemic diseases.

Biomarkers as Prognostic Predictors and Therapeutic Guide in Critically Ill Patients: Clinical Evidence

A biomarker is a molecule that can be measured in a biological sample in an objective, systematic, and precise way, whose levels indicate whether a process is normal or pathological. Knowing the most important biomarkers and their characteristics is the key to precision medicine in intensive and perioperative care. Biomarkers can be used to diagnose, in assessment of disease severity, to stratify risk, to predict and guide clinical decisions, and to guide treatments and response to them. In this review, we will analyze what characteristics a biomarker should have and how to ensure its usefulness, and we will review the biomarkers that in our opinion can make their knowledge more useful to the reader in their clinical practice, with a future perspective. These biomarkers, in our opinion, are lactate, C-Reactive Protein, Troponins T and I, Brain Natriuretic Peptides, Procalcitonin, MR-ProAdrenomedullin and BioAdrenomedullin, Neutrophil/lymphocyte ratio and lymphopenia, Proenkephalin, NefroCheck, Neutrophil gelatinase-associated lipocalin (NGAL), Interleukin 6, Urokinase-type soluble plasminogen activator receptor (suPAR), Presepsin, Pancreatic Stone Protein (PSP), and Dipeptidyl peptidase 3 (DPP3). Finally, we propose an approach to the perioperative evaluation of high-risk patients and critically ill patients in the Intensive Care Unit (ICU) based on biomarkers.

HSF1 Attenuates the Release of Inflammatory Cytokines Induced by Lipopolysaccharide through Transcriptional Regulation of Atg10

Autophagy plays an important role in endotoxemic mice, and heat shock factor 1 (HSF1) plays a crucial protective role in endotoxemic mice. However, the protective mechanisms of HSF1 are poorly understood. In this text, bioinformatics analysis, chromatin immunoprecipitation, and electrophoresis mobility shift assay were employed to investigate the underlying mechanisms. The results showed that the release of inflammatory cytokines increased and autophagy decreased significantly in Hsf1^-/- endotoxemic mice compared with those in Hsf1^+/+ endotoxemic mice. HSF1 could directly bind to the noncoding promoter region of the autophagy-related gene 10 (Atg10). The expression of ATG10 and the ratio of LC3-II/LC3-I were obviously decreased in LPS-treated Hsf1^-/- peritoneal macrophages (PM) versus those in LPS-treated Hsf1^+/+ PM. Overexpression of HSF1 increased the level of the ATG10 protein and enhanced the ratio of LC3-II/LC3-I in RAW264.7 cells. In contrast, silencing of HSF1 decreased the expression of ATG10 and markedly lowered the ratio of LC3-II/LC3-I. In a cotransfected cell experiment, the upregulation of autophagy by overexpression HSF1 was reversed by small interfering RNA (siRNA)-ATG10. Compared with the overexpression HSF1, the release of inflammatory cytokines induced by lipopolysaccharide (LPS) was decreased in pcDNA3.1-HSF1 with siRNA-ATG10 cotransfected RAW264.7 cells. On the other hand, the decrease of autophagy by siRNA-HSF1 was compensated by overexpression of ATG10. Compared with siRNA-HSF1, the release of inflammatory cytokines induced by LPS was increased in siRNA-HSF1 with pcDNA3.1-ATG10 cotransfected RAW264.7 cells. These results presented a novel mechanism that HSF1 attenuated the release of inflammatory cytokines induced by LPS through transcriptional regulation of Atg10. Targeting of HSF1-Atg10-autophagy might be an attractive strategy in endotoxemia therapeutics. IMPORTANCE HSF1 plays an important protective role in endotoxemic mice. However, the protective mechanisms of HSF1 are poorly understood. In the present study, we demonstrated that HSF1 upregulated ATG10 through specifically binding Atg10 promoter's noncoding region in LPS-treated PM and RAW264.7 cells. By depletion of HSF1, the expression of ATG10 was significantly decreased, leading to aggravate releasing of inflammatory cytokines in LPS-treated RAW264.7 cells. These findings provided a new mechanism of HSF1 in endotoxemic mice.

Salidroside protects against intestinal barrier dysfunction in septic mice by regulating IL‑17 to block the NF‑κB and p38 MAPK signaling pathways

Sepsis is a systemic inflammatory response syndrome, mainly caused by infection or suspected infectious factors. The intestine is not only one of the most easily involved organs in the course of sepsis, but also the dynamic organ for the course of sepsis. The present study investigated the protective effect and mechanism of salidroside on intestinal barrier dysfunction of septic mice. Briefly, C57BL/6 mice were used to establish a septic model and then administered with salidroside. The ileum tissues of mice were examined by histopathological examination. Fluorescein isothiocyanate-dextran concentration was measured. IL-17, IL-6, IL-13 and TNF-α levels in ileum tissues and NF-κB and p38 MAPK activations were detected by ELISA and the expressions of NF-κB p65 and p38 MAPK protein with their phosphorylation and intestinal tight junction proteins were gauged by western blotting. The above assays were performed again to investigate the effect of anti-IL-17A and salidroside (160 mg/kg) alone or in combination. The septic model induced the ileum tissue injury, increased intestinal permeability and TNF-α, IL-17 and IL-6 levels, activated NF-κB and p38 MAPK pathways, promoted the expressions of NF-κB p65 and p38 MAPK and their phosphorylation, while suppressing the levels of IL-13 and intestinal tight junction proteins. Salidroside and anti-IL-17A partially reversed the above effects of septic model, which in combination further strengthened the reversing effect. Collectively, salidroside protected against intestinal barrier dysfunction in septic mice by downregulating IL-17 level to inhibit NF-κB and p38 MAPK signaling pathways, thus providing a new treatment direction.

Expression of Th1/2/17 Cytokines in CML with or without Pulmonary Bacterial and Fungal Coinfection

Background

Tyrosine kinase inhibitors (TKIs) are the standard therapy for patients with chronic myeloid leukemia (CML). While their use greatly increases patient survival rates and can lead to normal life expectancy, bacterial infections in the lungs continue to play a significant role in determining patient outcomes.

Methods

In this study, the medical records of 272 CML and 53 healthy adults were analyzed. Information on age, sex, body temperature, procalcitonin (PCT), C-reactive protein (CRP), and cytokine levels were collected from patients. Since the data belonged to a nonstate distribution, we used the Mann-Whitney U test to examine differences between groups. Cut-off values were analyzed by receiver operating characteristic (ROC) curves.

Results

No significant differences in the Th1/2/17 levels were observed in relation to TKI treatment. Further analysis showed that the levels of the interleukins IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-22, IL-12p70, IL-17A, IL-17F, and IL-1β, interferon (IFN-γ), and tumor necrosis factors (TNF α and β) were higher in patients with pulmonary bacterial infections compared with uninfected patients. IL-6, IL-8, and IL-10 levels in CML patients with bacterial and fungal coinfection were higher than those in patients without infection. The areas under the ROC curves (AUCs) were found to be 0.73 for IL-5, 0.84 for IL-6, 0.82 for IL-8, 0,71 for IL-10, and 0.84 for TNF-α. AUC values were higher for patients with pulmonary bacterial infection, especially IL-6 (AUC = 0.84, cut-off = 13.78 pg/ml) and IL-8 (AUC = 0.82, cut-off = 14.35 pg/ml), which were significantly better than those for CRP (AUC = 0.80, cut-off = 6.18 mg/l), PCT (AUC = 0.71, cut-off = 0.25 ng/ml), and body temperature (AUC = 0.68, cut-off = 36.8°C). In addition, according to the cut-off values, we found that 83.33% of patients with pulmonary bacterial infections had IL-6 ≥ 13.78 pg/ml, while when IL-6, IL-8, and IL-10 levels simultaneously exceeded the cut-off values, the probability of pulmonary bacterial infection was 93.55%.

Conclusions

TKI treatment did not appear to affect cytokine expression in CML patients. However, CML patients with pulmonary bacterial infection had significantly higher levels of Th1/2/17 cytokines. In particular, abnormally elevated IL-6, IL-8, and IL-10 levels were associated with a pulmonary bacterial infection in patients with CML.

The cholesteryl-ester transfer protein isoform (CETPI) and derived peptides: new targets in the study of Gram-negative sepsis

BACKGROUND

Sepsis is a syndrome where the dysregulated host response to infection threatens the life of the patient. The isoform of the cholesteryl-ester transfer protein (CETPI) is synthesized in the small intestine, and it is present in human plasma. CETPI and peptides derived from its C-terminal sequence present the ability to bind and deactivate bacterial lipopolysaccharides (LPS). The present study establishes the relationship between the plasma levels of CETPI and disease severity of sepsis due to Gram-negative bacteria.

METHODS

Plasma samples from healthy subjects and patients with positive blood culture for Gram-negative bacteria were collected at the Intensive Care Unit (ICU) of INCMNSZ (Mexico City). 47 healthy subjects, 50 patients with infection, and 55 patients with sepsis and septic shock, were enrolled in this study. CETPI plasma levels were measured by an enzyme-linked immunosorbent assay and its expression confirmed by Western Blot analysis. Plasma cytokines (IL-1β, TNFα, IL-6, IL-8, IL-12p70, IFNγ, and IL-10) were measured in both, healthy subjects, and patients, and directly correlated with their CETPI plasma levels and severity of clinical parameters. Sequential Organ Failure Assessment (SOFA) scores were evaluated at ICU admission and within 24 h of admission. Plasma LPS and CETPI levels were also measured and studied in patients  with liver dysfunction.

RESULTS

The level of CETPI in plasma was found to be higher in patients with positive blood culture for Gram-negative bacteria that in control subjects, showing a direct correlation with their SOFA values. Accordingly, septic shock patients showing a high CETPI plasma concentration, presented a negative correlation with cytokines IL-8, IL-1β, and IL-10. Also, in patients  with liver dysfunction, since higher CETPI levels correlated with a high plasma LPS concentration, LPS neutralization carried out by CETPI might be considered a physiological response that will have to be studied in detail.

CONCLUSIONS

Elevated levels of plasma CETPI were associated with disease severity and organ failure in patients  with Gram-negative bacteraemia, defining CETPI as a protein implicated in the systemic response to LPS.

The Combined Use of Interleukin-6 with Serum Albumin for Mortality Prediction in Critically Ill Elderly Patients: The Interleukin-6-to-albumin Ratio

Background

The association between interleukin-6 (IL-6) and serum albumin (ALB) with mortality in critically ill elderly patients, either as stand-alone biomarkers or in combination, has been scarcely reported. We, therefore, aimed to investigate the prognostic value of the IL-6-to-albumin ratio in this special population.

Patients and methods

This was a cross-sectional study conducted in the mixed intensive care unit (ICU) of two university-affiliated hospitals in Malaysia. Consecutive elderly patients (aged above or equal to 60 years) admitted to the ICU, who underwent simultaneous measurement of plasma IL-6 and serum ALB, were recruited. The prognostic value of the IL-6-to-albumin ratio was assessed by analysis of the receiver-operating characteristic (ROC) curve.

Results

A total of 112 critically ill elderly patients were recruited. The outcome of all-cause ICU mortality was 22.3%. The calculated IL-6-to-albumin ratio was significantly higher in the non-survivors compared to the survivors {14.1 [interquartile range (IQR), 6.5-26.7] vs 2.5 [(IQR, 0.6-9.2) pg/mL, p <0.001]}. The area under the curve (AUC) of IL-6-to-albumin ratio for discrimination of ICU mortality was 0.766 [95% confidence interval (CI), 0.667-0.865, p <0.001] which was slightly higher than that of IL-6 and albumin alone. The ideal cut-off value of the IL-6-to-albumin ratio was above 5.7 with a sensitivity of 80.0% and specificity of 64.4%. After adjusting for severity of illness, the IL-6-to-albumin ratio remained as an independent predictor of ICU mortality with an adjusted odd ratio of 0.975 (95% CI, 0.952-0.999, p = 0.039).

Conclusion

The IL-6-to-albumin ratio offers a slight improvement in mortality prediction than either of its constituent individual biomarkers and as such, it may be a potential tool to aid in the prognostication of critically ill elderly patients although this requires further validation in a larger prospective study.

How to cite this article

Lim KY, Shukeri WFWM, Hassan WMNW, Mat-Nor MB, Hanafi MH. The Combined Use of Interleukin-6 with Serum Albumin for Mortality Prediction in Critically Ill Elderly Patients: The Interleukin-6-to-albumin Ratio. Indian J Crit Care Med 2022;26(10):1126-1130.

Pd@Pt Nanodendrites as Peroxidase Nanomimics for Enhanced Colorimetric ELISA of Cytokines with Femtomolar Sensitivity

Colorimetric enzyme-linked immunosorbent assay (ELISA) has been widely applied as the gold-standard method for cytokine detection over decades. However, it has become a critical challenge to further improve the detection sensitivity of ELISA as limited by the catalytic activity of enzymes. Herein, we report an enhanced colorimetric ELISA for ultrasensitive detection of interleukin-6 (IL-6, as a model cytokine for demonstration) using Pd@Pt core@shell nanodendrites (Pd@Pt NDs) as peroxidase nanomimics (named "Pd@Pt ND ELISA"), pushing the sensitivity up to femtomolar level. Specifically, the Pd@Pt NDs are rationally engineered by depositing Pt atoms on Pd nanocubes (NCs) to generate rough dendrite-like Pt skins on the Pd surfaces via Volmer-Weber growth mode. They can be produced on a large scale with highly uniform size, shape, composition, and structure. They exhibit significantly enhanced peroxidase-like catalytic activity with catalytic constants (K cat ) more than 2000-fold higher than those of horseradish peroxidase (HRP, an enzyme commonly used in ELISA). Using Pd@Pt NDs as the signal labels, the Pd@Pt ND ELISA presents strong colorimetric signals for the quantitative determination of IL-6 with a wide dynamic range of 0.05-100 pg mL-1 and an ultralow detection limit of 0.044 pg mL-1 (1.7 fM). This detection limit is 21-fold lower than that of conventional HRP-based ELISA. The reproducibility and specificity of the Pd@Pt ND ELISA are excellent. More significantly, the Pd@Pt ND ELISA was validated for analyzing IL-6 in human serum samples with high accuracy and reliability through recovery tests. Our results demonstrate that the colorimetric Pd@Pt ND ELISA is a promising biosensing tool for ultrasensitive determination of cytokines and thus is expected to be applied in a variety of clinical diagnoses and fundamental biomedical studies.

Simultaneous detection of sepsis host response biomarkers in whole blood using electrochemical biosensor

Sepsis is a silent killer, caused by a syndromic reaction of the body's immune system to an infection that is typically the ultimate pathway to mortality due to numerous infectious diseases, including COVID-19 across the world. In the United States alone, sepsis claims 220,000 lives, with a dangerously high fatality rate between 25% and 50%. Early detection and treatment can avert 80% of sepsis mortality which is currently unavailable in most healthcare institutions. The novelty in this work is the ability to simultaneously detect eight (IL-6, IL-8, IL-10, IP-10, TRAIL, d-dimer, CRP, and G-CSF) heterogeneous immune response biomarkers directly in whole blood without the need for dilution or sample processing. The DETecT sepsis (Direct Electrochemical Technique Targeting Sepsis) 2.0 sensor device leverages electrochemical impedance spectroscopy as a technique to detect subtle binding interactions at the metal/semi-conductor sensor interface and reports results within 5 min using only two drops (~100 μl) of blood. The device positively (r >0.87) correlated with lab reference standard LUMINEX for clinical translation using 40 patient samples. The developed device showed diagnostic accuracy greater than 80% (AUC >0.8) establishing excellent specific and sensitive response. Portable handheld user-friendly feature coupled with precise quantification of immune biomarkers makes the device amenable in a versatile setting providing insights on patient's immune response. This work highlights an innovative solution of enhancing sepsis care and management in the absence of a decision support device in the continuum of sepsis care.

nCD64 index as a novel inflammatory indicator for the early prediction of prognosis in infectious and non-infectious inflammatory diseases: An observational study of febrile patients

Background

Generally, febrile patients admitted to the Department of Infectious Diseases, Fudan University Affiliated Huashan Hospital, China may eventually be diagnosed as infectious (ID) or non-infectious inflammatory diseases (NIID). Furthermore, mortality from sepsis remains incredibly high. Thus, early diagnosis and prognosis evaluation of sepsis is necessary. Here, we investigated neutrophil (n)CD64 index profile in a cohort of febrile patients and explored its diagnostic and prognostic value in ID and NIID.

Methods

This observational cohort study enrolled 348 febrile patients from the Emergency Department and Department of Infectious Diseases. nCD64 index were detected using flow cytometry, and dynamically measured at different timepoints during follow-up. Procalcitonin (PCT), C-reactive protein (CRP), and ferritin levels were measured routinely. Finally, the diagnostic and prognostic value of nCD64 index were evaluated by receiver operating characteristic (ROC) analysis and Kaplan-Meier curve analysis.

Results

Of included 348 febrile patients, 238, 81, and 29 were categorized into ID, NIID, and lymphoma groups, respectively. In ID patients, both SOFA score and infection site had impact on nCD64 index expression. In NIID patients, adult-onset Still’s disease patients had the highest nCD64 index value, however, nCD64 index couldn’t distinguish between ID and NIID. Regardless of the site of infection, nCD64 index was significantly higher in bacterial and viral infections than in fungal infections, but it could not discriminate between bacterial and viral infections. In bloodstream infections, gram-negative (G-) bacterial infections showed an obvious increase in nCD64 index compared to that of gram-positive (G+) bacterial infections. nCD64 index has the potential to be a biomarker for distinguishing between DNA and RNA virus infections. The routine measurement of nCD64 index can facilitate septic shock diagnosis and predict 28-day hospital mortality in patients with sepsis. Serial monitoring of nCD64 index in patients with sepsis is helpful for evaluating prognosis and treatment efficacy. Notably, nCD64 index is more sensitive to predict disease progression and monitor glucocorticoid treatment in patients with NIID.

Conclusions

nCD64 index can be used to predict 28-day hospital mortality in patients with sepsis and to evaluate the prognosis. Serial determinations of nCD64 index can be used to predict and monitor disease progression in patients with NIID.

Predictive value of computed tomography for short-term mortality in patients with acute respiratory distress syndrome: a systematic review

The best available evidence and the predictive value of computed tomography (CT) findings for prognosis in patients with acute respiratory distress syndrome (ARDS) are unknown. We systematically searched three electronic databases (MEDLINE, CENTRAL, and ClinicalTrials.gov). A total of 410 patients from six observational studies were included in this systematic review. Of these, 143 patients (34.9%) died due to ARDS in short-term. As for CT grade, the CTs used ranged from 4- to 320-row. The index test included diffuse attenuations in one study, affected lung in one study, well-aerated lung region/predicted total lung capacity in one study, CT score in one study and high-resolution CT score in two studies. Considering the CT findings, pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 62% (95% confidence interval [CI] 30–88%), 76% (95% CI 57–89%), 2.58 (95% CI 2.05–2.73), 0.50 (95% CI 0.21–0.79), and 5.16 (95% CI 2.59–3.46), respectively. This systematic review revealed that there were major differences in the definitions of CT findings, and that the integration of CT findings might not be adequate for predicting short-term mortality in ARDS. Standardisation of CT findings and accumulation of further studies by CT with unified standards are warranted.

Biomarker combinations in predicting sepsis in hospitalized children with fever

Sepsis is among the leading causes of critical illness worldwide. It includes physiologic, pathologic, and biochemical abnormalities, induced by infection. Novel methods for recognizing a dysregulated inflammatory response and predicting associated mortality must be developed. Our aim was to investigate biomarkers that characterize a pro-inflammatory and anti-inflammatory response in patients with fever by comparing predictive validity for sepsis. 165 patients with fever were enrolled in this study, 55 of them had sepsis according to pSOFA criteria. All patients had blood samples drawn at the time of inclusion and after 24 h. CRP, PCT and also IL-6, IL-8 and sFAS levels were significantly higher in patients with sepsis. The AUC of CRP to predict sepsis was 0.799, all the other biomarkers had AUC's lower than that. Cytokines, when used as a single marker, did not show a significant diagnostic performance We analyzed various models of biomarker combinations. CRP combined with sFAS showed increase in sensitivity in predicting sepsis (88% vs. 83%). The highest AUC was achieved, when CRP, IL-6, sFAS and sVCAM-1 markers were combined 0.830 (95% CI 0.762-0.884) with a sensitivity of 70% and specificity of 84%. vs. 0.799 for CRP alone.

Doppler trans-thoracic echocardiography for detection of pulmonary hypertension in adults

BACKGROUND

Pulmonary hypertension (PH) is an important cause of morbidity and mortality, which leads to a substantial loss of exercise capacity. PH ultimately leads to right ventricular overload and subsequent heart failure and early death. Although early detection and treatment of PH are recommended, due to the limited responsiveness to therapy at late disease stages, many patients are diagnosed at a later stage of the disease because symptoms and signs of PH are nonspecific at earlier stages. While direct pressure measurement with right-heart catheterisation is the clinical reference standard for PH, it is not routinely used due to its invasiveness and complications. Trans-thoracic Doppler echocardiography is less invasive, less expensive, and widely available compared to right-heart catheterisation; it is therefore recommended that echocardiography be used as an initial diagnosis method in guidelines. However, several studies have questioned the accuracy of noninvasively measured pulmonary artery pressure. There is substantial uncertainty about the diagnostic accuracy of echocardiography for the diagnosis of PH.

OBJECTIVES

To determine the diagnostic accuracy of trans-thoracic Doppler echocardiography for detecting PH.

SEARCH METHODS

We searched MEDLINE, Embase, Web of Science Core Collection, ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform from database inception to August 2021, reference lists of articles, and contacted study authors. We applied no restrictions on language or type of publication.

SELECTION CRITERIA

We included studies that evaluated the diagnostic accuracy of trans-thoracic Doppler echocardiography for detecting PH, where right-heart catheterisation was the reference standard. We excluded diagnostic case-control studies (two-gate design), studies where right-heart catheterisation was not the reference standard, and those in which the reference standard threshold differed from 25 mmHg. We also excluded studies that did not provide sufficient diagnostic test accuracy data (true-positive [TP], false-positive [FP], true-negative [TN], and false-negative [FN] values, based on the reference standard). We included studies that provided data from which we could extract TP, FP, TN, and FN values, based on the reference standard. Two authors independently screened and assessed the eligibility based on the titles and abstracts of records identified by the search. After the title and abstract screening, the full-text reports of all potentially eligible studies were obtained, and two authors independently assessed the eligibility of the full-text reports.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and extracted data from each of the included studies. We contacted the authors of the included studies to obtain missing 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 regarding types of PH, methods to estimate the right atrial pressure, and threshold of index test to diagnose PH. All analyses were performed using the Review Manager 5, SAS and STATA statistical software.

MAIN RESULTS

We included 17 studies (comprising 3656 adult patients) assessing the diagnostic accuracy of Doppler trans-thoracic echocardiography for the diagnosis of PH. The included studies were heterogeneous in terms of patient distribution of age, sex, WHO classification, setting, country, positivity threshold, and year of publication. The prevalence of PH reported in the included studies varied widely (from 6% to 88%). The threshold of index test for PH diagnosis varied widely (from 30 mmHg to 47 mmHg) and was not always prespecified. No study was assigned low risk of bias or low concern in each QUADAS-2 domain assessed. Poor reporting, especially in the index test and reference standard domains, hampered conclusive judgement about the risk of bias. There was little consistency in the thresholds used in the included studies; therefore, common thresholds contained very sparse data, which prevented us from calculating summary points of accuracy estimates. With a fixed specificity of 86% (the median specificity), the estimated sensitivity derived from the median value of specificity using HSROC model was 87% (95% confidence interval [CI]: 78% to 96%). Using a prevalence of PH of 68%, which was the median among the included studies conducted mainly in tertiary hospitals, diagnosing a cohort of 1000 adult patients under suspicion of PH would result in 88 patients being undiagnosed with PH (false negatives) and 275 patients would avoid unnecessary referral for a right-heart catheterisation (true negatives). In addition, 592 of 1000 patients would receive an appropriate and timely referral for a right-heart catheterisation (true positives), while 45 patients would be wrongly considered to have PH (false positives). Conversely, when we assumed low prevalence of PH (10%), as in the case of preoperative examinations for liver transplantation, the number of false negatives and false positives would be 13 and 126, respectively.

AUTHORS' CONCLUSIONS

Our evidence assessment of echocardiography for the diagnosis of PH in adult patients revealed several limitations. We were unable to determine the average sensitivity and specificity at any particular index test threshold and to explain the observed variability in results. The high heterogeneity of the collected data and the poor methodological quality would constrain the implementation of this result into clinical practice. Further studies relative to the accuracy of Doppler trans-thoracic echocardiography for the diagnosis of PH in adults, that apply a rigorous methodology for conducting diagnostic test accuracy studies, are needed.

Comparison of Two Predictive Models of Sepsis in Critically Ill Patients Based on the Combined Use of Inflammatory Markers

Background

Sepsis is a systemic inflammatory response due to infection, resulting in organ dysfunction. Timely targeted interventions can improve prognosis. Inflammation plays a crucial role in the process of sepsis. To identify potential sepsis early, we developed and validated a nomogram model and a simple risk scoring model for predicting sepsis in critically ill patients.

Methods

The medical records of adult patients admitted to our intensive care unit (ICU) from August 2017 to December 2020 were analyzed. Patients were randomly divided into a training cohort (70%) and a validation cohort (30%). A nomogram model was developed through multivariate logistic regression analysis. The continuous variables included in nomogram model were transformed into dichotomous variables. Then, a multivariable logistic regression analysis was performed based on these dichotomous variables, and the odds ratio (OR) for each variable was used to construct a simple risk scoring model. The receiver operating characteristic curves (ROC) were constructed, and the area under the curve (AUC) was calculated.

Results

A total of 2074 patients were enrolled. Finally, white blood cell (WBC), C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT) and neutrophil-to-lymphocyte ratio (NLR) were included in our models. The AUC of the nomogram model and the simple risk scoring model were 0.854 and 0.842, respectively. The prediction performance of the two models on sepsis is comparable (p = 0.1298).

Conclusion

This study combining five commonly available inflammatory markers (WBC, CRP, IL-6, PCT and NLR) developed a nomogram model and a simple risk scoring model to predict sepsis in critically ill patients. Although the prediction performance of the two models is comparable, the simple risk scoring model may be simpler and more practical for clinicians to identify potential sepsis in critically ill patients at an early stage and strategize treatments.

NUTRIC Score Is Not Superior to mNUTRIC Score in Prediction of Mortality of COVID-19 Patients

OBJECTIVES

The NUTRIC (nutrition risk in the critically ill) score and the modified NUTRIC score are two scoring systems that show the nutritional risk status and severity of acute disease of patients. The only difference between them is the examination of interleukin-6 (IL-6) level. The aim of this study was to investigate whether or not the NUTRIC score is superior to the mNUTRIC score in the prediction of mortality of patients with COVID-19 followed up in the Intensive Care Unit (ICU). Material and Method. This retrospective study included 322 patients followed up in ICU with a diagnosis of COVID-19. A record was made of demographic data, laboratory values, clinical results, and mortality status. All the data of the patients were compared between high and low variations of the NUTRIC score and the mNUTRIC score.

RESULTS

A high NUTRIC score was determined in 62 patients and a high mNUTRIC score in 86 patients. The need for invasive mechanical ventilation, the use of vasopressors in ICU, the development of acute kidney injury, and mortality rates were statistically significantly higher in the patients with high NUTRIC and high mNUTRIC scores than in those with low scores (p = 0.0001 for all). The AUC values were 0.791 for high NUTRIC score and 0.786 for high mNUTRIC score (p = 0.0001 for both). No statistically significant difference was determined between the two scoring systems.

CONCLUSION

Although the NUTRIC score was seen to be superior to the mNUTRIC score, no statistically significant difference was determined. Therefore, when IL-6 cannot be examined, the mNUTRIC score can be considered safe and effective for the prediction of mortality in COVID-19 patients.

Contributory Role of BLT2 in the Production of Proinflammatory Cytokines in Cecal Ligation and Puncture-Induced Sepsis

BLT2 is a low-affinity receptor for leukotriene B4, a potent lipid mediator of inflammation generated from arachidonic acid via the 5-lipoxygenase pathway. The aim of this study was to investigate whether BLT2 plays any role in sepsis, a systemic inflammatory response syndrome caused by infection. A murine model of cecal ligation and puncture (CLP)-induced sepsis was used to evaluate the role of BLT2 in septic inflammation. In the present study, we observed that the levels of ligands for BLT2 (LTB4 [leukotriene B4] and 12(S)-HETE [12(S)-hydroxyeicosatetraenoic acid]) were significantly increased in the peritoneal lavage fluid and serum from mice with CLP-induced sepsis. We also observed that the levels of BLT2 as well as 5-LO and 12-LO, which are synthesizing enzymes for LTB4 and 12(S)-HETE, were significantly increased in lung and liver tissues in the CLP mouse model. Blockade of BLT2 markedly suppressed the production of sepsis-associated cytokines (IL-6 [interleukin-6], TNF-α [tumor necrosis factor alpha], and IL-1β [interleukin-1β] as well as IL-17 [interleukin-17]) and alleviated lung inflammation in the CLP group. Taken together, our results suggest that BLT2 cascade contributes to lung inflammation in CLP-induced sepsis by mediating the production of inflammatory cytokines. These findings suggest that BLT2 may be a potential therapeutic target for sepsis patients.

Cytokine Expression of Lung Bacterial Infection in Newly Diagnosed Adult Hematological Malignancies

Adult patients with hematological malignancies are frequently accompanied by bacterial infections in the lungs when they are first diagnosed. Sputum culture, procalcitonin (PCT), C-reactive protein (CRP), body temperature, and other routinely used assays are not always reliable. Cytokines are frequently abnormally produced in adult hematological malignancies associated with a lung infection, it is uncertain if cytokines can predict lung bacterial infections in individuals with hematological malignancies. Therefore, we reviewed 541 adult patients newly diagnosed with hematological malignancies, of which 254 patients had lung bacterial infections and 287 patients had no other clearly diagnosed infections. To explore the predictive value of cytokines for pulmonary bacterial infection in adult patients with hematological malignancies. Our results show that IL-4, IL-6, IL-8, IL-10, IL-12P70, IL-1β, IL-2, IFN-γ, TNF-α, TNF-β and IL-17A are in the lungs The expression level of bacterially infected individuals was higher than that of patients without any infections (P<0.05). Furthermore, we found that 88.89% (200/225) of patients with IL-6 ≥34.12 pg/ml had a bacterial infection in their lungs. With the level of IL-8 ≥16.35 pg/ml, 71.67% (210/293) of patients were infected. While 66.10% (193/292) of patients had lung bacterial infections with the level of IL-10 ≥5.62 pg/ml. When IL-6, IL-8, and IL-10 were both greater than or equal to their Cutoff-value, 98.52% (133/135) of patients had lung bacterial infection. Significantly better than PCT ≥0.11 ng/ml [63.83% (150/235)], body temperature ≥38.5°C [71.24% (62/87)], CRP ≥9.3 mg/L [53.59% (112/209)] the proportion of lung infection. In general. IL-6, IL-8 and IL-10 are abnormally elevated in patients with lung bacterial infections in adult hematological malignancies. Then, the abnormal increase of IL-6, IL-8 and IL-10 should pay close attention to the possible lung bacterial infection in patients.

Dracocephalum moldavica Ethanol Extract Suppresses LPS-Induced Inflammatory Responses through Inhibition of the JNK/ERK/NF-κB Signaling Pathway and IL-6 Production in RAW 264.7 Macrophages and in Endotoxic-Treated Mice

The excessive synthesis of interleukin-6 (IL-6) is related to cytokine storm in COVID-19 patients. Moreover, blocking IL-6 has been suggested as a treatment strategy for inflammatory diseases such as sepsis. Sepsis is a severe systemic inflammatory response syndrome with high mortality. In the present study, we investigated the anti-inflammatory and anti-septic effects and the underlying mechanisms of Dracocephalum moldavica ethanol extract (DMEE) on lipopolysaccharide (LPS)-induced inflammatory stimulation in RAW 264.7 macrophages along with septic mouse models. We found that DMEE suppressed the release of inflammatory mediators NO and PGE₂ and inhibited both the mRNA and protein expression levels of iNOS and COX-2, respectively. In addition, DMEE reduced the release of proinflammatory cytokines, mainly IL-6 and IL-1β, in RAW 264.7 cells by inhibiting the phosphorylation of JNK, ERK and p65. Furthermore, treatment with DMEE increased the survival rate and decreased the level of IL-6 in plasma in LPS-induced septic shock mice. Our findings suggest that DMEE elicits an anti-inflammatory effect in LPS-stimulated RAW 264.7 macrophages and an anti-septic effect on septic mouse model through the inhibition of the ERK/JNK/NF-κB signaling cascades and production of IL-6.

Mechanisms Underlying the Effects of Lianhua Qingwen on Sepsis-Induced Acute Lung Injury: A Network Pharmacology Approach

Background and Purpose: Sepsis is a life-threatening condition associated with secondary multiple organ injury. Acute lung injury (ALI) caused by sepsis has high morbidity and mortality in critical care units. Lianhua Qingwen (LHQW) is a traditional Chinese medicine composing of 11 herbs and 2 medicinal minerals. LHQW exhibits anti-inflammatory activity and is effective in treating pneumonia. Our study aimed to evaluate the effect of LHQW on sepsis-induced ALI and its underlying mechanism.

Materials and Methods: A network pharmacology approach was used to predict the bioactive components and effective targets of LHQW in treating ALI. We established ALI model C57/BL6 mice via an intraperitoneal injection of LPS and inhibited p53 expression by pifithrin-α, in order to validate the mechanism by which LHQW exerted protective role in ALI. Hematoxylin-eosin staining was conducted to assess the severity of lung injury. The severity of inflammation was evaluated based on MPO (myeloperoxidase) activity. TUNEL assay was employed to detect apoptotic cells. The levels of p53 and caspase-3 were tested by immunohistochemical staining and Western blotting. The expression levels of Bcl-2, Bax, cytochrome C and caspase-9 were detected by Western blotting.

Results: A total of 80 genes were associated with LHQW in the treatment of ALI. After PPI network construction, four active components (quercetin, luteolin, kaempferol and wogonin) and 10 target genes (AKT1, TP53, IL6, VEGFA, TNF, JUN, STAT3, MAPK8, MAPK1, and EGF) were found to be essential for ALI treatment. GO and KEGG analyses indicated that apoptosis pathway was mainly involved in the LHQW-ALI network. Animal experiments showed that LHQW was able to attenuate LPS-induced ALI, and medium-dose LHQW exhibited the most prominent effect. LHQW could inhibit the overexpression of p53 induced by LPS and suppress p53-mediated intrinsic apoptotic pathways by decreasing the levels of Bax, caspase-3 and caspase-9, increasing the expression of Bcl-2, and attenuating the release of cytochrome C in ALI mice.

Conclusion: This study reveals that LHQW may alleviate LPS-induced ALI via inhibiting p53-mediated intrinsic apoptosis pathways.

Electrochemical Immunosensing of Interleukin-6 in Human Cerebrospinal Fluid and Human Serum as an Early Biomarker for Traumatic Brain Injury

In this work, we develop a label-free electrochemical immunosensor for the detection of interleukin-6 (IL-6) in human cerebrospinal fluid (CSF) and serum for diagnostic and therapeutic monitoring. The IL-6 immunosensor is fabricated from gold interdigitated electrode arrays (IDEAs) that are modified with IL-6 antibodies for direct antigen recognition and capture. A rigorous surface analysis of the sensor architecture was conducted to ensure high structural fidelity and performance. Electrochemical characterization was conducted by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and sensing was performed using differential pulse voltammetry (DPV). The DPV peak current was used to quantify IL-6 in buffer, CSF, and serum in the range 1 pg mL^-1 < [IL-6] < 1 μg mL^-1. The IL-6 IDEA sensor achieved a limit of detection (LOD) of 1.63 pg mL^-1 in PBS, 2.34 pg mL^-1 in human CSF, and 11.83 pg mL^-1 in human serum. The sensor response is linear in the concentration range 10 pg mL^-1 < [IL-6] < 10 ng mL^-1, and the sensor is selective for IL-6 over other common cytokines, including IL-10 and TNF-α. EIS measurements showed that the resistance to charge transfer, R _CT, decreases upon IL-6 binding, an observation attributed to a structural change upon Ab-Ag binding that opens up the architecture so that the redox probe can more easily access the electrode surface. The IL-6 IDEA sensor can be used as a point-of-care diagnostic tool to deliver rapid results (∼3 min) in clinical settings for traumatic brain injury, and potentially address the unmet need for effective diagnostic and prognostic tools for other cytokine-related illnesses, such as sepsis and COVID-19 induced cytokine storms. Given the interdigitated electrode form factor, it is likely that the performance of the sensor can be further improved through redox cycling.

Aloe-Emodin-Mediated Photodynamic Therapy Attenuates Sepsis-Associated Toxins in Selected Gram-Positive Bacteria In Vitro

Sepsis is an acute inflammatory response that leads to life-threatening complications if not quickly and adequately treated. Cytolysin, hemolysin, and pneumolysin are toxins produced by gram-positive bacteria and are responsible for resistance to antimicrobial drugs, cause virulence and lead to sepsis. This work assessed the effects of aloe-emodin (AE) and photodynamic therapy (PDT) on sepsis-associated gram-positive bacterial toxins. Standard and antibiotic-resistant Enterococcus faecalis, Staphylococcus aureus, and Streptococcus pneumonia bacterial strains were cultured in the dark with varying AE concentrations and later irradiated with 72 J/cm-2 light. Colony and biofilm formation was determined. CCK-8, Griess reagent reaction, and ELISA assays were done on bacteria-infected RAW264.7 cells to determine the cell viability, NO, and IL-1β and IL-6 pro-inflammatory cytokines responses, respectively. Hemolysis and western blot assays were done to determine the effect of treatment on hemolysis activity and sepsis-associated toxins expressions. AE-mediated PDT reduced bacterial survival in a dose-dependent manner with 32 μg/ml of AE almost eliminating their survival. Cell proliferation, NO, IL-1β, and IL-6 cytokines production were also significantly downregulated. Further, the hemolytic activities and expressions of cytolysin, hemolysin, and pneumolysin were significantly reduced following AE-mediated PDT. In conclusion, combined use of AE and light (435 ± 10 nm) inactivates MRSA, S. aureus (ATCC 29213), S. pneumoniae (ATCC 49619), MDR-S. pneumoniae, E. faecalis (ATCC 29212), and VRE (ATCC 51299) in an AE-dose dependent manner. AE and light are also effective in reducing biofilm formations, suppressing pro-inflammatory cytokines, hemolytic activities, and inhibiting the expressions of toxins that cause sepsis.

Problems of Pathogenesis and Pathogenetic Therapy of COVID-19 from the Perspective of the General Theory of Pathological Systems (General Pathological Processes)

The COVID-19 pandemic examines not only the state of actual health care but also the state of fundamental medicine in various countries. Pro-inflammatory processes extend far beyond the classical concepts of inflammation. They manifest themselves in a variety of ways, beginning with extreme physiology, then allostasis at low-grade inflammation, and finally the shockogenic phenomenon of "inflammatory systemic microcirculation". The pathogenetic core of critical situations, including COVID-19, is this phenomenon. Microcirculatory abnormalities, on the other hand, lie at the heart of a specific type of general pathological process known as systemic inflammation (SI). Systemic inflammatory response, cytokine release, cytokine storm, and thrombo-inflammatory syndrome are all terms that refer to different aspects of SI. As a result, the metabolic syndrome model does not adequately reflect the pathophysiology of persistent low-grade systemic inflammation (ChSLGI). Diseases associated with ChSLGI, on the other hand, are risk factors for a severe COVID-19 course. The review examines the role of hypoxia, metabolic dysfunction, scavenger receptors, and pattern-recognition receptors, as well as the processes of the hemophagocytic syndrome, in the systemic alteration and development of SI in COVID-19.

Association between IL-6 and severe disease and mortality in COVID-19 disease: a systematic review and meta-analysis

BACKGROUND

So far, SARS-CoV-2 is the seventh coronavirus found to infect humans and cause disease with quite a strong infectivity. Patients diagnosed as severe or critical cases are prone to multiple organ dysfunction syndrome, acute respiratory distress syndrome and even death. Proinflammatory cytokine IL-6 has been reported to be associated with the severity of disease and mortality in patients with COVID-19.

OBJECTIVE

This systematic review and meta-analysis were carried out to evaluate the association between IL-6 and severe disease and mortality in COVID-19 disease.

METHODS

A systematic literature search using China National Knowledge Infrastructure, Wanfang databases, China Science and Technology Journal Database, Chinese Biomedical Literature, Embase, PubMed and Cochrane Central Register of Controlled Trials was performed from inception until 16 January 2021.

RESULTS

12 studies reported the value of IL-6 for predicting the severe disease in patients with COVID-19. The pooled area under the curve (AUC) was 0.85 (95% CI 0.821 to 0.931). 5 studies elaborated the predictive value of IL-6 on mortality. The pooled sensitivity, specificity and AUC were 0.15 (95% CI 0.13 to 0.17, I²=98.9%), 0.73 (95% CI 0.65 to 0.79, I²=91.8%) and 0.531 (95% CI 0.451 to 0.612), respectively. Meta-regression analysis showed that country, technique used, cut-off, sample, study design and detection time did not contribute to the heterogeneity of mortality.

CONCLUSION

IL-6 is an adequate predictor of severe disease in patients infected with the COVID-19. The finding of current study may guide clinicians and healthcare providers in identifying potentially severe or critical patients with COVID-19 at the initial stage of the disease. Moreover, we found that only monitoring IL-6 levels does not seem to predict mortality and was not associated with COVID-19's mortality.

PROSPERO REGISTRATION NUMBER

CRD42021233649.

Interleukin 6 and Aneurysmal Subarachnoid Hemorrhage. A Narrative Review

Interleukin 6 (IL-6) is a prominent proinflammatory cytokine. Neuroinflammation in general, and IL-6 signaling in particular, appear to play a major role in the pathobiology and pathophysiology of aneurysm formation and aneurysmal subarachnoid hemorrhage (SAH). Most importantly, elevated IL-6 CSF (rather than serum) levels appear to correlate with delayed cerebral ischemia (DCI, “vasospasm”) and secondary (“vasospastic”) infarctions. IL-6 CSF levels may also reflect other forms of injury to the brain following SAH, i.e., early brain damage and septic complications of SAH and aneurysm treatment. This would explain why many researchers have found an association between IL-6 levels and patient outcomes. These findings clearly suggest CSF IL-6 as a candidate biomarker in SAH patients. However, at this point, discrepant findings in variable study settings, as well as timing and other issues, e.g., defining proper clinical endpoints (i.e., secondary clinical deterioration vs. angiographic vasospasm vs. secondary vasospastic infarct) do not allow for its routine use. It is also tempting to speculate about potential therapeutic measures targeting elevated IL-6 CSF levels and neuroinflammation in SAH patients. Corticosteroids and anti-platelet drugs are indeed used in many SAH cases (not necessarily with the intention to interfere with detrimental inflammatory signaling), however, no convincing benefit has been demonstrated yet. The lack of a robust clinical perspective against the background of a relatively large body of data linking IL-6 and neuroinflammation with the pathophysiology of SAH is somewhat disappointing. One underlying reason might be that most relevant studies only report correlative data. The specific molecular pathways behind elevated IL-6 levels in SAH patients and their various interactions still remain to be delineated. We are optimistic that future research in this field will result in a better understanding of the role of neuroinflammation in the pathophysiology of SAH, which in turn, will translate into the identification of suitable biomarkers and even potential therapeutic targets.

Toward the Rapid Diagnosis of Sepsis: Detecting Interleukin-6 in Blood Plasma Using Functionalized Screen-Printed Electrodes with a Thermal Detection Methodology

This paper reports the detection of the inflammatory and sepsis-related biomarker, interleukin-6 (IL-6), in human blood plasma using functionalized screen-printed electrodes (SPEs) in conjunction with a thermal detection methodology, termed heat-transfer method (HTM). SPEs are functionalized with antibodies specific for IL-6 through electrodeposition of a diazonium linking group and N'-ethylcarbodiimide hydrochloride (EDC) coupling, which was tracked through the use of cyclic voltammetry and Raman spectroscopy. The functionalized SPEs are mounted inside an additively manufactured flow cell and connected to the HTM device. We demonstrate the ability to detect IL-6 at clinically relevant concentrations in PBS buffer (pH = 7.4) with no significant interference from the similarly sized sepsis-related biomarker procalcitonin (PCT). The limit of detection (3σ) of the system is calculated to correspond to 3.4 ± 0.2 pg mL^-1 with a working range spanning the physiologically relevant concentration levels in both healthy individuals and patients with sepsis, indicating the sensitivity of the sensor is suitable for the application. Further experiments helped provide a proof-of-application through the detection of IL-6 in blood plasma with no significant interference observed from PCT or the constituents of the medium. Due to the selectivity, sensitivity, straightforward operation, and low cost of production, this sensor platform has the potential for use as a traffic light sensor for the multidetection of inflammatory biomarkers for the diagnosis of sepsis and other conditions in which the rapid testing of blood biomarkers has vital clinical application.

Accuracy for Mortality Prediction With Additive Biomarkers Including Interleukin-6 in Critically Ill Patients: A Multicenter Prospective Observational Study

OBJECTIVES

Several inflammation markers have been reported to be associated with unfavorable clinical outcomes in critically ill patients. We aimed to elucidate whether serum interleukin-6 concentration considered with Sequential Organ Failure Assessment score can better predict mortality in critically ill patients.

DESIGN

A prospective observational study.

SETTING

Five university hospitals in 2016-2018.

PATIENTS

Critically ill adult patients who met greater than or equal to two systemic inflammatory response syndrome criteria at admission were included, and those who died or were discharged within 48 hours were excluded.

INTERVENTIONS

Inflammatory biomarkers including interleukin (interleukin)-6, -8, and -10; tumor necrosis factor-α; C-reactive protein; and procalcitonin were blindly measured daily for 3 days. Area under the receiver operating characteristic curve for Sequential Organ Failure Assessment score at day 2 according to 28-day mortality was calculated as baseline. Combination models of Sequential Organ Failure Assessment score and additional biomarkers were developed using logistic regression, and area under the receiver operating characteristic curve calculated in each model was compared with the baseline.

MEASUREMENTS AND MAIN RESULTS

Among 161 patients included in the study, 18 (11.2%) did not survive at day 28. Univariate analysis for each biomarker identified that the interleukin-6 (days 1-3), interleukin-8 (days 0-3), and interleukin-10 (days 1-3) were higher in nonsurvivors than in survivors. Analyses of 28-day mortality prediction by a single biomarker showed interleukin-6, -8, and -10 at days 1-3 had a significant discrimination power, and the interleukin-6 at day 3 had the highest area under the receiver operating characteristic curve (0.766 [0.656-0.876]). The baseline area under the receiver operating characteristic curve for Sequential Organ Failure Assessment score predicting 28-day mortality was 0.776 (0.672-0.880). The combination model using additional interleukin-6 at day 3 had higher area under the receiver operating characteristic curve than baseline (area under the receiver operating characteristic curve = 0.844, area under the receiver operating characteristic curve improvement = 0.068 [0.002-0.133]), whereas other biomarkers did not improve accuracy in predicting 28-day mortality.

CONCLUSIONS

Accuracy for 28-day mortality prediction was improved by adding serum interleukin-6 concentration to Sequential Organ Failure Assessment score.

Novel Diagnostics and Therapeutics in Sepsis

Sepsis management demands early diagnosis and timely treatment that includes source control, antimicrobial therapy, and resuscitation. Currently employed diagnostic tools are ill-equipped to rapidly diagnose sepsis and isolate the offending pathogen, which limits the ability to offer targeted and lowest-toxicity treatment. Cutting edge diagnostics and therapeutics in development may improve time to diagnosis and address two broad management principles: (1) source control by removing the molecular infectious stimulus of sepsis, and (2) attenuation of the pathological immune response allowing the body to heal. This review addresses novel diagnostics and therapeutics and their role in the management of sepsis.

New putative insights into neprilysin (NEP)-dependent pharmacotherapeutic role of roflumilast in treating COVID-19

Nowadays, coronavirus disease 2019 (COVID-19) represents the most serious inflammatory respiratory disease worldwide. Despite many proposed therapies, no effective medication has yet been approved. Neutrophils appear to be the key mediator for COVID-19-associated inflammatory immunopathologic, thromboembolic and fibrotic complications. Thus, for any therapeutic agent to be effective, it should greatly block the neutrophilic component of COVID-19. One of the effective therapeutic approaches investigated to reduce neutrophil-associated inflammatory lung diseases with few adverse effects was roflumilast. Being a highly selective phosphodiesterase-4 inhibitors (PDE4i), roflumilast acts by enhancing the level of cyclic adenosine monophosphate (cAMP), that probably potentiates its anti-inflammatory action via increasing neprilysin (NEP) activity. Because activating NEP was previously reported to mitigate several airway inflammatory ailments; this review thoroughly discusses the proposed NEP-based therapeutic properties of roflumilast, which may be of great importance in curing COVID-19. However, further clinical studies are required to confirm this strategy and to evaluate its in vivo preventive and therapeutic efficacy against COVID-19.

Identification of the Diagnostic Signature of Sepsis Based on Bioinformatic Analysis of Gene Expression and Machine Learning

BACKGROUND

Sepsis is a life-threatening disease caused by the dysregulated host response to the infection and the major cause of death of patients in the intensive care unit (ICU).

OBJECTIVE

Early diagnosis of sepsis could significantly reduce in-hospital mortality. Though generated from infection, the development of sepsis follows its own psychological process and disciplines, alters with gender, health status and other factors. Hence, the analysis of mass data by bioinformatics tools and machine learning is a promising method for exploring early diagnosis.

METHODS

We collected miRNA and mRNA expression data of sepsis blood samples from Gene Expression Omnibus (GEO) and ArrayExpress databases, screened out differentially expressed genes (DEGs) by R software, predicted miRNA targets on TargetScanHuman and miRTarBase websites, conducted Gene Ontology (GO) term and KEGG pathway enrichment analysis based on overlapping DEGs. The STRING database and Cytoscape were used to build protein-protein interaction (PPI) network and predict hub genes. Then we constructed a Random Forest model by using the hub genes to assess sample type.

RESULTS

Bioinformatic analysis of GEO dataset revealed 46 overlapping DEGs in sepsis. The PPI network analysis identified five hub genes, SOCS3, KBTBD6, FBXL5, FEM1C and WSB1. Random Forest model based on these five hub genes was used to assess GSE95233 and GSE95233 datasets, and the area under the curve (AUC) of ROC was 0.900 and 0.7988, respectively, which confirmed the efficacy of this model.

CONCLUSION

The integrated analysis of gene expression in sepsis and the effective Random Forest model built in this study may provide promising diagnostic methods for sepsis.

A linear prognostic score based on the ratio of interleukin-6 to interleukin-10 predicts outcomes in COVID-19

BACKGROUND

Prognostic tools are required to guide clinical decision-making in COVID-19.

METHODS

We studied the relationship between the ratio of interleukin (IL)-6 to IL-10 and clinical outcome in 80 patients hospitalized for COVID-19, and created a simple 5-point linear score predictor of clinical outcome, the Dublin-Boston score. Clinical outcome was analysed as a three-level ordinal variable ("Improved", "Unchanged", or "Declined"). For both IL-6:IL-10 ratio and IL-6 alone, we associated clinical outcome with a) baseline biomarker levels, b) change in biomarker level from day 0 to day 2, c) change in biomarker from day 0 to day 4, and d) slope of biomarker change throughout the study. The associations between ordinal clinical outcome and each of the different predictors were performed with proportional odds logistic regression. Associations were run both "unadjusted" and adjusted for age and sex. Nested cross-validation was used to identify the model for incorporation into the Dublin-Boston score.

FINDINGS

The 4-day change in IL-6:IL-10 ratio was chosen to derive the Dublin-Boston score. Each 1 point increase in the score was associated with a 5.6 times increased odds for a more severe outcome (OR 5.62, 95% CI -3.22-9.81, P = 1.2 × 10-9). Both the Dublin-Boston score and the 4-day change in IL-6:IL-10 significantly outperformed IL-6 alone in predicting clinical outcome at day 7.

INTERPRETATION

The Dublin-Boston score is easily calculated and can be applied to a spectrum of hospitalized COVID-19 patients. More informed prognosis could help determine when to escalate care, institute or remove mechanical ventilation, or drive considerations for therapies.

FUNDING

Funding was received from the Elaine Galwey Research Fellowship, American Thoracic Society, National Institutes of Health and the Parker B Francis Research Opportunity Award.

Diagnostic accuracy of physical examination for detecting pelvic fractures among blunt trauma patients: a systematic review and meta-analysis

BACKGROUND

Pelvic fractures are common among blunt trauma patients, and timely and accurate diagnosis can improve patient outcomes. However, it remains unclear whether physical examinations are sufficient in this context. This study aims to perform a systematic review and meta-analysis of studies on the diagnostic accuracy and clinical utility of physical examination for pelvic fracture among blunt trauma patients.

METHODS

Studies were identified using the MEDLINE, EMBASE, and CENTRAL databases starting from the creation of the database to January 2020. A total of 20 studies (49,043 patients with 8300 cases [16.9%] of pelvic fracture) were included in the quality assessment and meta-analysis. Two investigators extracted the data and evaluated the risk of bias in each study. The meta-analysis involved a hierarchical summary receiver operating curve (ROC) model to calculate the diagnostic accuracy of the physical exam. Subgroup analysis assessed the extent of between-study heterogeneity. Clinical utility was assessed using decision curve analysis.

RESULTS

The median prevalence of pelvic fracture was 10.5% (interquartile range, 5.1-16.5). The pooled sensitivity (and corresponding 95% confidence interval) of the hierarchical summary ROC parameters was 0.859 (0.761-0.952) at a given specificity of 0.920, which was the median value among the included studies. Subgroup analysis revealed that the pooled sensitivity among patients with a Glasgow Coma Scale score ≥ 13 was 0.933 (0.847-0.998) at a given specificity of 0.920. The corresponding value for patients with scores ≤ 13 was 0.761 (0.560-0.932). For threshold probability < 0.01 with 10-15% prevalence, the net benefit of imaging tests was higher than that of physical examination.

CONCLUSION

Imaging tests should be performed in all trauma patients regardless of findings from physical examination or patients' levels of consciousness. However, the clinical role of physical examination should be considered given the prevalence and threshold probability in each setting.

SARS-CoV-2 Bound Human Serum Albumin and Systemic Septic Shock

The emergence of the COVID-19 virus and the subsequent pandemic have driven a great deal of research activity. The effects of COVID-19 are caused by the severe respiratory syndrome coronavirus 2 (SARS-CoV-2) and it is the underlying actions of SARs-CoV-2 virions on the endothelial glycocalyx that we consider here. One of the key factors in COVID-19 infection is its almost unique age-related profile, with a doubling in mortality every 10 years after the age of 50. The endothelial glycocalyx layer is essential in maintaining normal fluid homeostasis, but is fragile and prone to pathophysiological damage. It is physiologically significant in capillary microcirculation and in fluid distribution to the tissues. Human serum albumin (HSA), the most abundant protein in plasma, is created in the liver which also maintains its concentration, but this reduces by 10-15% after 50 years of age. HSA transports hormones, free fatty acids and maintains oncotic pressure, but SARS-CoV-2 virions bind competitively to HSA diminishing its normal transport function. Furthermore, hypoalbuminemia is frequently observed in patients with such conditions as diabetes, hypertension, and chronic heart failure, i.e., those most vulnerable to SARS-CoV-2 infection. Hypoalbuminemia, coagulopathy, and vascular disease have been linked in COVID-19 and have been shown to predict outcome independent of age and morbidity. Hypoalbuminemia is also known factor in sepsis and Acute respiratory distress syndrome (ARDS) occurs when fluids build-up in the alveoli and it is associated with sepsis, whose mechanism is systemic, being associated with the fluid and logistic mechanisms of the circulation. Glycocalyx damage is associated with changes plasma protein concentration, particularly HSA and blockage of albumin transport can produce the systemic symptoms seen in SARS-CoV-2 infection and sepsis. We therefore conclude that albumin binding to SARS-CoV-2 virions may inhibit the formation of the endothelial glycocalyx by inhibition of albumin transport binding sites. We postulate that albumin therapy to replace bound albumin might alleviate some of the symptoms leading to sepsis and that clinical trials to test this postulation should be initiated as a matter of urgency.

The profile of peripheral blood lymphocyte subsets and serum cytokines in children with 2019 novel coronavirus pneumonia

Objectives

The study was aimed at investigating the characteristics of peripheral blood lymphocyte subsets and serum cytokines in children with 2019 novel coronavirus (2019-nCoV) pneumonia.

Methods

Children with 2019-nCoV pneumonia or with respiratory syncytial virus (RSV) pneumonia were included. Data including lymphocyte subsets and serum cytokines were collected and analyzed.

Results

56 patients were included in the study, 40 children with 2019-nCoV pneumonia and 16 children with RSV pneumonia. Compared with children with RSV pneumonia, patients with 2019-nCoV pneumonia had higher count of CD3+8+ lymphocyte, higher percentages of CD3+, CD3+8+ lymphocytes and a lower percentage of CD19+ lymphocyte. The serum IL-10 level was significantly higher in children with RSV pneumonia. One 2019-nCoV pneumonia child who was with an obvious increase of IL-10 developed severe pneumonia.

Conclusions

Immune response played a very important role in the development of 2019-nCoV pneumonia. The effective CD8+ T cell response might influence the severity of 2019-nCoV pneumonia. The adaptable change in IL-10 level might contribute to the relatively mild pneumonia symptoms in children with 2019-nCoV pneumonia and bacterial co-infection might be a risk factor of severe 2019-nCoV pneumonia.

ADAR1 Alleviates Inflammation in a Murine Sepsis Model via the ADAR1-miR-30a-SOCS3 Axis

Adenosine deaminase acting on double-stranded RNA 1 (ADAR1) mediates adenosine-to-inosine (A-to-I) RNA editing events. ADAR1 is highly expressed in “septic” macrophages and in small intestinal tissues of mice with sepsis. Overexpression of ADAR1 suppresses inflammation and intestinal damage. However, the specific underlying mechanism is unclear. This study was conducted to explore how microRNA (miRNA) regulates the anti-inflammatory mechanism of macrophages following ADAR1 upregulation. A murine sepsis model was established by cecal ligation and puncture (CLP). Mice were randomly assigned to sham, CLP, and CLP+ADAR1 groups. Hematoxylin and eosin (HE) staining and fluorescence isothiocyanate-dextran were used to evaluate intestinal injury and permeability. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting, and Luminex assays were performed to detect changes in the expression of inflammatory cytokines. Adenoviruses were used to express ADAR1 in RAW 264.7 cells. Ribonucleoprotein immunoprecipitation analysis was conducted to detect the binding of ADAR1 and miRNAs. A dual-luciferase reporter assay was used to detect the binding of miRNAs and regulatory factors. We observed that ADAR1 significantly increased the expression of suppressor of cytokine signaling 3 (SOCS3) in macrophages and reduced the expression of interleukin-6 in macrophages and the serum, thereby reducing intestinal permeability and mucosal injury in mice with sepsis. The RNA-ribonucleoprotein immunoprecipitation binding assay and qRT-PCR demonstrated a direct interaction between ADAR1 and pri-miR-30a. The luciferase assay demonstrated that SOCS3 was significantly inhibited by miR-30a-5p, the mature product of miR-30a. Thus, ADAR1 exerts a protective effect against sepsis by reducing inflammation and organ damage via the ADAR1-miR-30a-SOCS3 axis.

Biomarkers for Point-of-Care Diagnosis of Sepsis

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. In 2017, almost 50 million cases of sepsis were recorded worldwide and 11 million sepsis-related deaths were reported. Therefore, sepsis is the focus of intense research to better understand the complexities of sepsis response, particularly the twin underlying concepts of an initial hyper-immune response and a counter-immunological state of immunosuppression triggered by an invading pathogen. Diagnosis of sepsis remains a significant challenge. Prompt diagnosis is essential so that treatment can be instigated as early as possible to ensure the best outcome, as delay in treatment is associated with higher mortality. In order to address this diagnostic problem, use of a panel of biomarkers has been proposed as, due to the complexity of the sepsis response, no single marker is sufficient. This review provides background on the current understanding of sepsis in terms of its epidemiology, the evolution of the definition of sepsis, pathobiology and diagnosis and management. Candidate biomarkers of interest and how current and developing point-of-care testing approaches could be used to measure such biomarkers is discussed.

The Influence of Photoperiod on the Action of Exogenous Leptin on Gene Expression of Proinflammatory Cytokines and Their Receptors in the Thoracic Perivascular Adipose Tissue (PVAT) in Ewes

Leptin resistance is either a condition induced by human obesity or a natural phenomenon associated with seasonality in ruminants. In the cardiovascular system, the leptin resistance state presence is a complex issue. Moreover, the perivascular adipose tissue (PVAT) appears to be crucial as a source of proinflammatory cytokines and as a site of interaction for leptin contributing to endothelium dysfunction and atherosclerosis progression. So the aim of this study was to examine the influence of the photoperiod on the action of exogenous leptin on gene expression of selected proinflammatory cytokines and their receptors in thoracic PVAT of ewe with or without prior lipopolysaccharide (LPS) stimulation. The experiment was conducted on 48 adult, female ewes divided into 4 group (n = 6 in each): control, with LPS intravenous (iv.) injection (400 ng/kg of BW), with leptin iv. injection (20 μg/kg BW), and with LPS and 30-minute-later leptin injection, during short-day (SD) and long-day (LD) seasons. Three hours after LPS/control treatment, animals were euthanized to collect the PVAT adherent to the aorta wall. The leptin injection enhanced IL1B gene expression only in the LD season; however, in both seasons leptin injection intensified LPS-induced increase in IL1B gene expression. IL1R2 gene expression was increased by leptin injection only in the SD season. Neither IL6 nor its receptor and signal transducer gene expressions were influenced by leptin administration. Leptin injection increased TNFA gene expression regardless of photoperiodic conditions. Only in the SD season did leptin treatment increase the gene expression of both TNFα receptors. To conclude, leptin may modulate the inflammatory reaction progress in PVAT. In ewe, the sensitivity of PVAT on leptin action is dependent upon the photoperiodic condition with stronger effects stated in the SD season.