Prognostic value of MIP-1 alpha, TGF-beta 2, sELAM-1, and sVCAM-1 in patients with gram-positive sepsis

Traumatic inflammatory response: pathophysiological role and clinical value of cytokines

Severe trauma is an intractable problem in healthcare. Patients have a widespread immune system response that is complex and vital to survival. Excessive inflammatory response is the main cause of poor prognosis and poor therapeutic effect of medications in trauma patients. Cytokines are signaling proteins that play critical roles in the body's response to injuries, which could amplify or suppress immune responses. Studies have demonstrated that cytokines are closely related to the severity of injuries and prognosis of trauma patients and help present cytokine-based diagnosis and treatment plans for trauma patients. In this review, we introduce the pathophysiological mechanisms of a traumatic inflammatory response and the role of cytokines in trauma patients. Furthermore, we discuss the potential of cytokine-based diagnosis and therapy for post-traumatic inflammatory response, although further clarification to elucidate the underlying mechanisms of cytokines following trauma is warranted.

The Basophil IL-18 Receptor Precisely Regulates the Host Immune Response and Malaria-Induced Intestinal Permeability and Alters Parasite Transmission to Mosquitoes without Effect on Gametocytemia

We have recently demonstrated that basophils are protective against intestinal permeability during malaria and contribute to reduced parasite transmission to mosquitoes. Given that IL-18 is an early cytokine/alarmin in malaria and has been shown to activate basophils, we sought to determine the role of the basophil IL-18R in this protective phenotype. To address this, we infected control [IL18r ^flox/flox or basoIL-18R (+)] mice and mice with basophils lacking the IL-18R [IL18r ^flox/flox × Basoph8 or basoIL-18R (-)] with Plasmodium yoelii yoelii 17XNL, a nonlethal strain of mouse malaria. Postinfection (PI), intestinal permeability, ileal mastocytosis, bacteremia, and levels of ileal and plasma cytokines and chemokines were measured through 10 d PI. BasoIL-18R (-) mice exhibited greater intestinal permeability relative to basoIL-18R (+) mice, along with increased plasma levels of proinflammatory cytokines at a single time point PI, day 4 PI, a pattern not observed in basoIL-18R (+) mice. Surprisingly, mosquitoes fed on basoIL-18R (-) mice became infected less frequently than mosquitoes fed on basoIL-18R (+) mice, with no difference in gametocytemia, a pattern that was distinct from that observed previously with basophil-depleted mice. These findings suggest that early basophil-dependent protection of the intestinal barrier in malaria is mediated by IL-18, and that basophil IL-18R-dependent signaling differentially regulates the inflammatory response to infection and parasite transmission.

Renal microvascular endothelial cell responses in sepsis-induced acute kidney injury

Microvascular endothelial cells in the kidney have been a neglected cell type in sepsis-induced acute kidney injury (sepsis-AKI) research; yet, they offer tremendous potential as pharmacological targets. As endothelial cells in distinct cortical microvascular segments are highly heterogeneous, this Review focuses on endothelial cells in their anatomical niche. In animal models of sepsis-AKI, reduced glomerular blood flow has been attributed to inhibition of endothelial nitric oxide synthase activation in arterioles and glomeruli, whereas decreased cortex peritubular capillary perfusion is associated with epithelial redox stress. Elevated systemic levels of vascular endothelial growth factor, reduced levels of circulating sphingosine 1-phosphate and loss of components of the glycocalyx from glomerular endothelial cells lead to increased microvascular permeability. Although coagulation disbalance occurs in all microvascular segments, the molecules involved differ between segments. Induction of the expression of adhesion molecules and leukocyte recruitment also occurs in a heterogeneous manner. Evidence of similar endothelial cell responses has been found in kidney and blood samples from patients with sepsis. Comprehensive studies are needed to investigate the relationships between segment-specific changes in the microvasculature and kidney function loss in sepsis-AKI. The application of omics technologies to kidney tissues from animals and patients will be key in identifying these relationships and in developing novel therapeutics for sepsis.

Investigation of the effect of melatonin administration on inflammatory mediators; MMP-2, TGF-β and VEGF levels in rats with sepsis

AIMS

Sepsis causes life-threatening tissue and organ dysfunctions caused by endogenous mediators in response to infection. Melatonin is a powerful endogenous anti-inflammatory agent and effective in reducing cellular damage. This study aimed to evaluate the changes in serum and liver tissue levels of VEGF, TGF-β and MMP-2 in melatonin-treated septic rats.

MATERIALS AND METHODS

Twenty-one Wistar-albino male rats were included in this study. Rats were randomly divided into three groups. Group 1 is sham-operated control (C) group, Group 2 is caecal ligation and puncture (CLP) group and Group 3 is melatonin-treated (10 mg/kg) (M-CLP) group. Serum and tissue samples were analysed. All procedures were carried out according to the ethical rules specified in Helsinki Declaration.

RESULTS

Sera MMP-2 levels were found higher than tissue MMP-2 levels in C and CLP (respectively, P = .048, P = .01). In CLP and M-CLP, serum TGF-β levels were higher than tissue TGF-β levels(respectively, P = .05, P = .01). Serum VEGF levels in CLP were found to be significantly higher than both C and M-CLP(P < .01).

CONCLUSION

MMP-2 levels may have increased because of the prevention of oxidative damage in sepsis, and this may increase the anti-inflammatory effect. Melatonin treatment may have a therapeutic effect against sepsis since it prevents the increase in serum VEGF level. A powerful endogenous antioxidant, may be a promising therapeutic agent on the mortality and morbidity of the disease, because of its lowering effect on serum VEGF, which is a poor prognostic factor in sepsis.

Potential Targets to Mitigate Trauma- or Sepsis-Induced Immune Suppression

In sepsis and trauma, pathogens and injured tissue provoke a systemic inflammatory reaction which can lead to overwhelming inflammation. Concurrent with the innate hyperinflammatory response is adaptive immune suppression that can become chronic. A current key issue today is that patients who undergo intensive medical care after sepsis or trauma have a high mortality rate after being discharged. This high mortality is thought to be associated with persistent immunosuppression. Knowledge about the pathophysiology leading to this state remains fragmented. Immunosuppressive cytokines play an essential role in mediating and upholding immunosuppression in these patients. Specifically, the cytokines Interleukin-10 (IL-10), Transforming Growth Factor-β (TGF-β) and Thymic stromal lymphopoietin (TSLP) are reported to have potent immunosuppressive capacities. Here, we review their ability to suppress inflammation, their dynamics in sepsis and trauma and what drives the pathologic release of these cytokines. They do exert paradoxical effects under certain conditions, which makes it necessary to evaluate their functions in the context of dynamic changes post-sepsis and trauma. Several drugs modulating their functions are currently in clinical trials in the treatment of other pathologies. We provide an overview of the current literature on the effects of IL-10, TGF-β and TSLP in sepsis and trauma and suggest therapeutic approaches for their modulation.

Modeling Early Stages of Bone and Joint Infections Dynamics in Humans: A Multi-Agent, Multi-System Based Model

Diagnosis and management of bone and joint infections (BJI) is a challenging task. The high intra and inter patient's variability in terms of clinical presentation makes it impossible to rely on a systematic description or classical statistical analysis for its diagnosis. Advances can be achieved through a better understanding of the system behavior that results from the interactions between the components at a micro-scale level, which is difficult to mastered using traditional methods. Multiple studies from the literature report factors and interactions that affect the dynamics of the BJI system. The objectives of this study were (i) to perform a systematic review to identify relevant interactions between agents (cells, pathogens) and parameters values that characterize agents and interactions, and (ii) to develop a two dimensional computational model of the BJI system based on the results of the systematic review. The model would simulate the behavior resulting from the interactions on the cellular and molecular levels to explore the BJI dynamics, using an agent-based modeling approach. The BJI system's response to different microbial inoculum levels was simulated. The model succeeded in mimicking the dynamics of bacteria, the innate immune cells, and the bone mass during the first stage of infection and for different inoculum levels in a consistent manner. The simulation displayed the destruction in bone tissue as a result of the alteration in bone remodeling process during the infection. The model was used to generate different patterns of system behaviors that could be analyzed in further steps. Simulations results suggested evidence for the existence of latent infections. Finally, we presented a way to analyze and synthesize massive simulated data in a concise and comprehensive manner based on the semi-supervised identification of ordinary differential equations (ODE) systems. It allows to use the known framework for temporal and structural ODE analyses and therefore summarize the whole simulated system dynamical behavior. This first model is intended to be validated by in vivo or in vitro data and expected to generate hypotheses to be challenged by real data. Step by step, it can be modified and complexified based on the test/validation iteration cycles.

A TGFBR2/SMAD2/DNMT1/miR-145 negative regulatory loop is responsible for LPS-induced sepsis

The critical roles of TGFBR2/Smad2 signaling have been established in LPS-induced sepsis, however, the underlying mechanisms by which TGFBR2/Smad2 signaling was regulated in LPS-induced sepsis are still confused. Here, miRNA-based on RNA-sequencing dataset revealed that miR-145 was significantly decreased in human umbilical vein endothelial cells (HUVECs) following LPS treatment. Bioinformatics, luciferase reporter and RNA immune co-precipitation (RIP) assays showed that miR-145 could directly target TGFBR2 and thus inactivated TGFBR2/Smad2 axis. On the contrary, luciferase reporter and chromatin immunoprecipitation (ChIP) analysis showed that Smad2 could directly bind to DNA methyltransferase 1 (DNMT1), the upregulation of which led to miR-145 promoter hypermethylation and downregulation of miR-145 expression, conversely promoting TGFBR2 expression. Notably, knockdown of TGFBR2 partially rescued the inhibition on miR-145 expression induced by LPS treatment. Additionally, we found that knockdown of TGFBR2 or overexpression of miR-145 attenuated LPS-induced sepsis and prolonged the overall survival of septic mice. Furthermore, TGFBR2 overexpression abrogated miR-145 overexpression-mediated attenuation on LPS-induced sepsis. Our results demonstrate the TGFBR2/SMAD2/DNMT1/miR-145 negative regulatory loop is responsible for LPS-induced sepsis.

MiR-145 negatively regulates TGFBR2 signaling responsible for sepsis-induced acute lung injury

This study aims to explore the roles of miR-145/TGFBR2 axis in sepsis-induced acute lung injury. Here, RNA-sequencing assay showed that miR-145 was significantly decreased in exosomes from sepsis patient blood samples. And miR-145 was decreased but TGFBR2 was increased in LPS-treated mice lung tissues or BEAS-2B cells in a time-dependent manner. Mechanistically, TGFBR2 was identified as a direct target of miR-145 and the downstream effector Smad3 was also suppressed in BEAS-2B cells with miR-145 overexpression. Pre-injection or post-injection of miR-145 agomir following LPS treatment attenuated LPS-induced inflammation, characterized as the downregulation of IL-2 and TNF-α secretion and ameliorate sepsis, and prolonged the overall survival of septic mice with lung injury. Additionally, TGFBR2 overexpression partially abrogated miR-145-mediated inhibition on LPS-induced inflammation and sepsis-induced acute lung injury. Importantly, TGF-β (Transforming growth factor-β) and miR-145 level displayed a negative correlation in sepsis patients. Thus, these results suggest that miR-145 could ameliorate sepsis-induced lung injury via inhibiting TGFBR2 signaling.

SUMO protease SENP1 acts as a ceRNA for TGFBR2 and thus activates TGFBR2/Smad signaling responsible for LPS-induced sepsis

This study aims to explore the roles and related mechanisms of SUMO protease SENP1 in sepsis. Here, RNA-sequencing assay showed that SENP1 was significantly increased in human umbilical vein endothelial cells (HUVECs) with LPS treatment. Gene set enrichment analysis (GSEA) of RNA-sequencing dataset revealed that a positive enrichment of inflammation signatures was observed in HUVECs with SENP1 3'UTR overexpression. Further functional annotation analysis revealed that SENP1 3'UTR overexpression was positively correlated with TGFBR2 signaling pathway. Mechanistically, TGFBR2 was identified as a ceRNA (competing endogenous RNA) target of SENP1 and the downstream effectors Smad2/3 were also overexpressed in HUVECs with SENP1 3'UTR overexpression. Injection of SENP1 siRNA following LPS treatment attenuated LPS-induced sepsis, evidenced by the downregulation of IL-2 and TNF-α secretion and prolonged the overall survival of septic mice. Consistent results were obtained in vitro. Additionally, TGFBR2 overexpression partially abrogated SENP1 siRNA-mediated inhibition on LPS-induced sepsis. Thus, these results suggest that SENP1 promotes sepsis via activating the TGFBR2 signaling.

Endothelial activation and dysfunction in severe fever with thrombocytopenia syndrome

Background

Pathogenesis of severe fever with thrombocytopenia syndrome (SFTS) has not been well described yet. Recent studies indicate that SFTSV could replicate in endothelial cells. Here we performed a case-control study to determine whether endothelial activation/dysfunction occurred in SFTSV infection and to identify the biomarkers reflecting endothelial dysfunction.

Methodology/Principal findings

In a case-control study of 134 SFTS patients and 68 healthy controls, serum levels of plasminogen activator inhibitor 1, tissue plasminogen activator, P-selectin, platelet endothelial cell adhesion molecular, CD40 ligand, E-selectin, vascular endothelial growth factor A, serum amyloid antigen 1 (SAA-1) and vascular cell adhesion molecular 1 were significantly enhanced in the patients than the controls (all P<0.05), indicating the occurrence of endothelial activation/dysfunction in SFTS. The intercellular adhesion molecular 1 (ICAM-1) and SAA-1 at the convalescent phase were also significantly associated with severe patients, after adjusting for the potential confounders. The odds ratio was estimated to be 3.364 (95% CI 1.074–10.534) for ICAM-1, and 1.881 (95% CI 1.166–3.034) for SAA-1, respectively. Cutoff value of 1.1×10⁷ pg/mL SAA-1 or 1.2×10⁶ pg/mL ICAM-1 were found to have moderate power of predicting fatal cases.

Conclusions

The endothelial dysfunction may be one of the pathogenic mechanism of SFTS. The serum levels of ICAM-1 and SAA-1 might be used to predict adverse outcome.

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral disease and first reported in the rural areas of China. Pathogenesis of the disease has not been well described yet. Recent studies indicated that SFTSV replicated in endothelial cells. So, we performed a case-control study to explore whether endothelial activation/dysfunction occurred in SFTSV infection and to identify biomarkers reflecting endothelial dysfunction. We found that the occurrence of endothelial activation/dysfunction in severe fever with thrombocytopenia syndrome and the serum levels of ICAM-1 and SAA-1 might be used to predict adverse outcome.

Immunotherapy: A promising approach to reverse sepsis-induced immunosuppression

Sepsis is defined as life-threatening organ dysfunction caused by dysregulated host responses to infection (Third International Consensus definition for Sepsis and septic shock). Despite decades of research, sepsis remains the leading cause of death in intensive care units. More than 40 clinical trials, most of which have targeted the sepsis-associated pro-inflammatory response, have failed. Thus, antibiotics and fluid resuscitation remain the mainstays of supportive care and there is intense need to discover and develop novel, targeted therapies to treat sepsis. Both pre-clinical and clinical studies over the past decade demonstrate unequivocally that sepsis not only causes hyper-inflammation, but also leads to simultaneous adaptive immune system dysfunction and impaired antimicrobial immunity. Evidences for immunosuppression include immune cell depletion (T cells most affected), compromised T cell effector functions, T cell exhaustion, impaired antigen presentation, increased susceptibility to opportunistic nosocomial infections, dysregulated cytokine secretion, and reactivation of latent viruses. Therefore, targeting immunosuppression provides a logical approach to treat protracted sepsis. Numerous pre-clinical studies using immunomodulatory agents such as interleukin-7, anti-programmed cell death 1 antibody (anti-PD-1), anti-programmed cell death 1 ligand antibody (anti-PD-L1), and others have demonstrated reversal of T cell dysfunction and improved survival. Therefore, identifying immunosuppressed patients with the help of specific biomarkers and administering specific immunomodulators holds significant potential for sepsis therapy in the future. This review focusses on T cell dysfunction during sepsis and discusses the potential immunotherapeutic agents to boost T cell function during sepsis and improve host resistance to infection.

Neonatal sepsis and inflammatory mediators

Neonatal sepsis is a major cause of morbidity and mortality and its signs and symptoms are nonspecific, which makes the diagnosis difficult. The routinely used laboratory tests are not effective methods of analysis, as they are extremely nonspecific and often cause inappropriate use of antibiotics. Sepsis is the result of an infection associated with a systemic inflammatory response with production and release of a wide range of inflammatory mediators. Cytokines are potent inflammatory mediators and their serum levels are increased during infections, so changes from other inflammatory effector molecules may occur. Although proinflammatory and anti-inflammatory cytokines have been identified as probable markers of neonatal infection, in order to characterize the inflammatory response during sepsis, it is necessary to analyze a panel of cytokines and not only the measurement of individual cytokines. Measurements of inflammatory mediators bring new options for diagnosing and following up neonatal sepsis, thus enabling early treatment and, as a result, increased neonatal survival. By taking into account the magnitude of neonatal sepsis, the aim of this review is to address the role of cytokines in the pathogenesis of neonatal sepsis and its value as a diagnostic criterion.

Elevated biomarkers of endothelial dysfunction/activation at ICU admission are associated with sepsis development

Widespread endothelial activation and dysfunction often precede clinical sepsis. Several endothelium-related molecules have been investigated as potential biomarkers for early diagnosis and/or prognosis of sepsis, providing different results depending on study designs. Such factors include endothelial adhesion molecules like E- and P-selectin, and the intercellular adhesion molecule-1, vascular endothelial cadherin, growth factors such as Angiopoietin-1 and -2 and vascular endothelial growth factor, as well as von Willebrand factor antigen. We sought to investigate whether circulating biomarkers of endothelial activation/dysfunction measured at ICU admission are associated with subsequent sepsis development. Eighty-nine critically-ill patients admitted to a general ICU who met no sepsis criteria were studied. Plasma or serum levels of the above-mentioned endothelium-derived molecules were measured during the first 24h post ICU; acute physiology and chronic health evaluation (APACHE) II and sequential organ failure assessment (SOFA) scores, age, sex, diagnostic category, and circulating procalcitonin (PCT) and C-reactive protein (CRP) levels were additionally measured or recorded. Forty-five patients subsequently became septic and 44 did not. Soluble (s) E- and P-selectin levels, circulating PCT, SOFA score and diagnostic category were significantly different between the two groups. Multiple logistic regression analysis associated elevated sE- and sP-selectin levels and SOFA with an increased risk of developing sepsis, while multiple Cox regression analysis identified sE- and sP-selectin levels as the only parameters related to sepsis appearance with time [RR=1.026, 95%CI=1.008-1.045, p=0.005; RR=1.005 (by 10 units), 95%CI=1.000-1.010, p=0.034, respectively]. When trauma patients were independently analyzed, multiple Cox regression analysis revealed sE-selectin to be the only molecule associated with sepsis development with time (RR=1.041, 95%CI: 1.019-1.065; p<0.001). In conclusion, in our cohort of initially non-septic critically-ill patients, high levels of the circulating endothelial adhesion molecules E- and P-selectin, measured at ICU admission, appear to be associated with sepsis development in time.

Soluble adhesion molecules as markers for sepsis and the potential pathophysiological discrepancy in neonates, children and adults

Sepsis is a severe and life-threatening systemic inflammatory response to infection that affects all populations and age groups. The pathophysiology of sepsis is associated with aberrant interaction between leukocytes and the vascular endothelium. As inflammation progresses, the adhesion molecules that mediate these interactions become shed from cell surfaces and accumulate in the blood as soluble isoforms that are being explored as potential prognostic disease biomarkers. We critically review the studies that have tested the predictive value of soluble adhesion molecules in sepsis pathophysiology with emphasis on age, as well as the underlying mechanisms and potential roles for inflammatory shedding. Five soluble adhesion molecules are associated with sepsis, specifically, E-selectin, L-selectin and P-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. While increased levels of these soluble adhesion molecules generally correlate well with the presence of sepsis, their degree of elevation is still poorly predictive of sepsis severity scores, outcome and mortality. Separate analyses of neonates, children and adults demonstrate significant age-dependent discrepancies in both basal and septic levels of circulating soluble adhesion molecules. Additionally, a range of both clinical and experimental studies suggests protective roles for adhesion molecule shedding that raise important questions about whether these should positively or negatively correlate with mortality. In conclusion, while predictive properties of soluble adhesion molecules have been researched intensively, their levels are still poorly predictive of sepsis outcome and mortality. We propose two novel directions for improving clinical utility of soluble adhesion molecules: the combined simultaneous analysis of levels of adhesion molecules and their sheddases; and taking age-related discrepancies into account. Further attention to these issues may provide better understanding of sepsis pathophysiology and increase the usefulness of soluble adhesion molecules as diagnostic and predictive biomarkers.

Cytokines in sepsis: potent immunoregulators and potential therapeutic targets--an updated view

Sepsis and septic shock are among the leading causes of death in intensive care units worldwide. Numerous studies on their pathophysiology have revealed an imbalance in the inflammatory network leading to tissue damage, organ failure, and ultimately, death. Cytokines are important pleiotropic regulators of the immune response, which have a crucial role in the complex pathophysiology underlying sepsis. They have both pro- and anti-inflammatory functions and are capable of coordinating effective defense mechanisms against invading pathogens. On the other hand, cytokines may dysregulate the immune response and promote tissue-damaging inflammation. In this review, we address the current knowledge of the actions of pro- and anti-inflammatory cytokines in sepsis pathophysiology as well as how these cytokines and other important immunomodulating agents may be therapeutically targeted to improve the clinical outcome of sepsis.

Biomarkers of endothelial activation/dysfunction in infectious diseases

Endothelial dysfunction contributes to the pathogenesis of a variety of potentially serious infectious diseases and syndromes, including sepsis and septic shock, hemolytic-uremic syndrome, severe malaria, and dengue hemorrhagic fever. Because endothelial activation often precedes overt endothelial dysfunction, biomarkers of the activated endothelium in serum and/or plasma may be detectable before classically recognized markers of disease, and therefore, may be clinically useful as biomarkers of disease severity or prognosis in systemic infectious diseases. In this review, the current status of mediators of endothelial cell function (angiopoietins-1 and -2), components of the coagulation pathway (von Willebrand Factor, ADAMTS13, and thrombomodulin), soluble cell-surface adhesion molecules (soluble E-selectin, sICAM-1, and sVCAM-1), and regulators of vascular tone and permeability (VEGF and sFlt-1) as biomarkers in severe infectious diseases is discussed in the context of sepsis, E. coli O157:H7 infection, malaria, and dengue virus infection.

Circulating sICAM-1 and sE-Selectin as biomarker of infection and prognosis in patients with systemic inflammatory response syndrome

BACKGROUND

Vascular endothelium activation is a key pathogenic step in systemic inflammatory response syndrome (SIRS) that can be triggered by both microbial and sterile proinflammatory stimuli. The relevance of soluble adhesion molecules as clinical biomarkers to discriminate between infectious and non-infectious SIRS, and the individual patient prognosis, has not been established.

METHODS

We prospectively measured by sandwich ELISA, serum levels of soluble E-Selectin (sE-Selectin), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble intercellular adhesion molecule-2 (sICAM-2) at ICU admission and at days 3, 7, 14 and 28 in patients with sepsis and at days 3 and 7 in patients with non-infectious SIRS.

RESULTS

At ICU admission, sE-Selectin, sVCAM-1 and sICAM-1 in patients with infectious SIRS were significantly higher than those found in patients with non-infectious SIRS. ROC analysis revealed that the AUC for infection identification was best for sICAM-1 (0.900±0.041; 95% CI 0.819-0.981; p<0.0001). Moreover, multivariate analysis showed that 4 variables were significantly and independently associated with mortality at 28 days: male gender (OR 15.90; 95% CI, 2.54-99.32), MODS score (OR 5.60; 95% CI, 1.67-18.74), circulating sE-Selectin levels (OR 4.81; 95% CI, 1.34-17.19) and sVCAM-1 concentrations (OR 4.80; 95% CI, 1.34-17.14).

CONCLUSIONS

Patients with SIRS secondary to infectious or non-infectious etiology show distinctive patterns of disturbance in serum soluble adhesion molecules. Serum ICAM-1 is a reliable biomarker for classifying patients with infectious SIRS from those with non-infectious SIRS. In addition, soluble E-Selectin is a prognostic biomarker with higher levels in patients with SIRS and fatal outcome.

Clinical utility of biomarkers of endothelial activation in sepsis--a systematic review

INTRODUCTION

A strong biologic rationale exists for targeting markers of endothelial cell (EC) activation as clinically informative biomarkers to improve diagnosis, prognostic evaluation or risk-stratification of patients with sepsis.

METHODS

The objective was to review the literature on the use of markers of EC activation as prognostic biomarkers in sepsis. MEDLINE was searched for publications using the keyword 'sepsis' and any of the identified endothelial-derived biomarkers in any searchable field. All clinical studies evaluating markers reflecting activation of ECs were included. Studies evaluating other exogenous mediators of EC dysfunction and studies of patients with malaria and febrile neutropenia were excluded.

RESULTS

Sixty-one studies were identified that fulfilled the inclusion criteria. Overall, published studies report positive correlations between multiple EC-derived molecules and the diagnosis of sepsis, supporting the critical role of EC activation in sepsis. Multiple studies also reported positive associations for mortality and severity of illness, although these results were less consistent than for the presence of sepsis. Very few studies, however, reported thresholds or receiver operating characteristics that would establish these molecules as clinically-relevant biomarkers in sepsis.

CONCLUSIONS

Multiple endothelial-derived molecules are positively correlated with the presence of sepsis in humans, and variably correlated to other clinically-important outcomes. The clinical utility of these biomarkers is limited by a lack of assay standardization, unknown receiver operating characteristics and lack of validation. Additional large-scale prospective clinical trials will be required to determine the clinical utility of biomarkers of endothelial activation in the management of patients with sepsis.

Heterogeneity in lipopolysaccharide responsiveness of endothelial cells identified by gene expression profiling: role of transcription factors

Interindividual differences of endothelial cells in response to endotoxins might contribute to the diversity in clinical outcome among septic patients. The present study was conducted to test the hypothesis that endothelial cells (EC) with high and low proinflammatory potential exist and to dissect the molecular basis underlying this phenomenon. Thirty human umbilical vein endothelial cell (HUVEC) lines were stimulated for 24 h with lipopolysaccharide (LPS) and screened for interleukin (IL)-8 production. Based on IL-8 production five low and five high producers, tentatively called types I and II responders, respectively, were selected for genome-wide gene expression profiling. From the 74 genes that were modulated by LPS in all type II responders, 33 genes were not influenced in type I responders. Among the 41 genes that were increased in both responders, 17 were expressed significantly stronger in type II responders. Apart from IL-8, significant differences in the expression of proinflammatory related genes between types I and II responders were found for adhesion molecules [intercellular adhesion molecule (ICAM-1), E-selectin)], chemokines [monocyte chemoattractant protein (MCP-1), granulocyte chemotactic protein (GCP-2)], cytokines (IL-6) and the transcription factor CCAAT/enhancer binding protein-delta (C/EBP-delta). Type I responders also displayed a low response towards tumour necrosis factor (TNF)-alpha. In general, maximal activation of nuclear factor (NF)-kappaB was achieved in type I responders at higher concentrations of LPS compared to type II responders. In the present study we demonstrate that LPS-mediated gene expression differs quantitatively and qualitatively in types I and II responders. Our results suggest a pivotal role for common transcription factors as a low inflammatory response was also observed after TNF-alpha stimulation. Further studies are required to elucidate the relevance of these findings in terms of clinical outcome in septic patients.

Serial changes in neutrophil-endothelial activation markers during the course of sepsis associated with disseminated intravascular coagulation

INTRODUCTION

For systematic elucidation of serial changes in neutrophil-endothelial activation markers as well as to investigate the correlationship among the inflammation markers, disseminated intravascular coagulation (DIC), and multiple organ dysfunction syndrome (MODS) in patients with sepsis, we made this prospective study.

MATERIALS AND METHODS

Forty-five patients with sepsis, severe sepsis, and septic shock were subdivided into two groups, 27 with DIC and 18 without DIC. Eight normal healthy volunteers served as control subjects. Serial levels of soluble L-, P-, and E-selectins, intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), thrombomodulin (sTM), and neutrophil elastase were measured within 12 h after the diagnosis of sepsis (day 0) and on days 1-4 after the diagnosis. The numbers of systemic inflammatory response syndrome (SIRS) criteria that patients met and the DIC score were determined simultaneously.

RESULTS

Acute Physiology and Chronic Health Evaluation (APACHE) II score was identical between the two groups. In the DIC patients, higher DIC scores, lower platelet counts, and more maximum numbers of SIRS criteria being met were observed compared with the non-DIC patients. The incidence of MODS and the number of the dysfunctioning organs were higher in the patients with DIC than those without DIC, and the DIC patients had poor outcome. Soluble L-selectin (sL-selectin) levels in both groups tended to be lower than those in the control subjects. All other parameters both in the two groups were continuously higher than those in the control subjects during study period. The levels of soluble E-selectin (sE-selectin), sICAM-1, sVCAM-1, neutrophil elastase, and sTM were more elevated in the DIC patients than those in the non-DIC patients. There were no differences in the sP-selectin levels between the two groups; however, more increased sP-selectin levels per platelet were found in the DIC patients compared with the non-DIC patients. Maximum DIC scores in the DIC group positively correlated with the peak levels of neutrophil elastase and sTM and the number of the dysfunctioning organs.

CONCLUSIONS

We found close relations among the neutrophil-endothelial cell interactions, DIC, and MODS in patients with sepsis, severe sepsis, and septic shock. The results indirectly confirm the concept that DIC can produce organ dysfunction and that DIC reflects an inflammatory disorder of the microvasculature.

Activation des molécules d’adhésion chez les patients en choc septique

OBJECTIVE

To analyze the pattern of adhesion molecules in patients with septic shock. Data sources. - References obtained from Pubmed databank.

DATA EXTRACTION

Models of inflammation linking endothelial dysfunction, adhesion molecules and septic states were analyzed.

DATA SYNTHESIS

The endothelium has been identified as the central effector in the inflammatory response. Adhesion molecules are strongly involved in the inflammatory process by modulating the leukocyte trafficking. The most important adhesion molecules are the selectins (E-, L-, and P-selectins) and members of the immunoglobulin superfamily (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1). Plasma levels of these molecules are increased in septic shock patients, which may be related to a marked activation of the endothelium. However, a dichotomous profile is observed between plasma and tissue expression. The inhibition of adhesive molecule actions could make it possible to control the inflammatory response.

Combination therapy with polymyxin B-immobilized fibre haemoperfusion and teicoplanin for sepsis due to methicillin-resistant Staphylococcus aureus

The aim of the present study was to determine whether treatment with polymyxin B-immobilized fibre (PMX-F) haemoperfusion, teicoplanin, or both in combination is effective in patients with methicillin-resistant Staphylococcus aureus (MRSA) sepsis. Sixty patients with MRSA sepsis were randomly assigned to one of four treatments: (A) PMX-F treatment (N=15), (B) teicoplanin treatment (N=15), (C) PMX-F and teicoplanin in combination (N=20) and (D) conventional therapy (N=10). PMX-F treatment was repeated twice. Teicoplanin was administered by intravenous injection. Plasma endotoxin levels were determined by endospecy test. Plasma endotoxin levels were reduced in groups A and C (P<0.05). Survival rates were 53, 47, 90, and 20% in groups A, B, C and D, respectively (group C versus group A, P<0.05; group C versus group B, P<0.01; group C versus group D,P <0.001). The mean duration of stay was 44, 42, 28 and 56 days in groups A, B, C and D, respectively. Our data suggest that combination therapy with PMX-F and teicoplanin is effective for sepsis caused by MRSA.

Cytokine modulation in sepsis and septic shock

Sepsis and septic shock are a major cause of morbidity and mortality in patients admitted to the intensive care unit. Since the introduction of antibiotic therapy, the mortality associated with sepsis has remained within the 30- 50% range. Sepsis constitutes the systemic response to infection. This response encompasses both pro-inflammatory and anti-inflammatory phases that are marked by the sequential generation of pro- and anti-inflammatory cytokines. Among the most important pro-inflammatory cytokines are TNF-alpha and IL-1beta. The pro-inflammatory effects of such cytokines are inhibited by soluble receptors/receptor antagonists and anti-inflammatory cytokines including IL-10 and transforming growth factor-beta. Modulation of the activity of both pro- and anti-inflammatory cytokines to improve outcome in patients with sepsis has been subject of multiple clinical studies. This review will examine clinical trials evaluating several strategies for blocking or attenuating TNF-alpha and IL-1beta activity. This review will also survey the current state of experimental therapies involving IL-10, transforming growth factor-beta, granulocyte colony-stimulating factor and IFN-phi. Finally, newer developments related to less known cytokines such as macrophage migration inhibitory factor and high mobility group 1 protein will be evaluated.

Circulating concentrations of chemokines in cord blood, neonates, and adults

Chemokines are critical for the movement of leukocytes. Chemotaxis is deficient in neonates, particularly those delivered prematurely, and this likely contributes to their increased vulnerability to sepsis. The concentrations of circulating chemokines in neonates have not been reported, nor is it known whether low chemokine concentrations contribute to their defective chemotaxis. We hypothesized that serum concentrations of chemokines 1) would be lower in preterm than term neonates, and 2) would be lower in preterm and term neonates than adults. Samples were obtained from preterm and term neonates with normal neutrophil and eosinophil counts, umbilical cord blood samples from pregnancies without clinical evidence of intra-amniotic infection, and healthy adult volunteers. The concentrations of epithelial neutrophil activating peptide-78, growth-related oncogene-alpha, eotaxin, RANTES (regulated upon activation, normal T cell expressed and secreted), and macrophage inflammatory protein-1 alpha were measured using specific ELISA. Serum concentrations from preterm infants were either similar to or higher than those measured in term neonates and adults. We conclude that the chemotactic defect observed in premature neonates is not the result of diminished circulating concentrations of any of the specific chemokines we measured.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit LPS-stimulated MIP-1alpha production and mRNA expression

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are neuropeptides with immunomodulatory properties, including the regulation of several proinflammatory mediators. Such mediators, for example chemokines, influence trafficking of inflammatory cells and contribute to shaping the immune response. In the present work, we studied the effect of VIP and PACAP on the CC chemokine macrophage inflammatory protein-1 alpha (MIP-1alpha) production in LPS-stimulated RAW 264.7 macrophage cell line. VIP and PACAP inhibited the production of MIP-1alpha in a dose-dependent manner and over a broad spectrum of LPS concentrations. The use of selective agonists and antagonists of VIP/PACAP receptors showed that type 1 VIP receptor (VPAC1) is the major receptor involved, but the type 2 VIP receptor (VPAC2) may be also implicated. By using selective PKA and PKC inhibitors and cAMP mimicked agents, we demonstrated a cAMP-dependent signalling pathway for the inhibitory effect of VIP/PACAP on MIP-1alpha production, although a minor non-mediated cAMP pathway was also involved. mRNA expression studies showed a down-regulation of MIP-1alpha gene expression by VIP and PACAP. Taken together, the present work strongly supports an anti-inflammatory role of VIP and PACAP by a new mechanism associated with impairment of a key component of the chemokine network.

Systemic endothelial activation is greater in septic than in traumatic-hemorrhagic shock but does not correlate with endothelial activation in skin biopsies

OBJECTIVE

Sepsis and severe trauma result in endothelial activation and damage. The activated endothelium expresses adhesion receptors that control leukocyte trafficking. After activation, some adhesion molecules are also released into plasma as soluble forms. The present study was designed to compare the expression of soluble cell adhesion molecules (sCAMs) in three groups of patients: those with septic shock, severe sepsis, and traumatic-hemorrhagic shock. In addition, the endothelial expression of these adhesive molecules was examined in skin biopsies.

DESIGN

Prospective observational study

SETTING

Intensive care unit at a university hospital

PATIENTS

The study included 15 patients with septic shock (by Bone's definition), 11 patients with severe sepsis (by Bone's definition), and 13 patients with traumatic-hemorrhagic shock. Fifteen healthy blood donors served as controls.

MEASUREMENTS AND MAIN RESULTS

Measurements of sCAMs were performed on days 1, 2, and 3 of the disease. On day 1, when compared with controls, sE-selectin, sP-selectin, soluble vascular cell adhesion molecule (sVCAM)-1, and soluble intercellular adhesion molecule (sICAM)-1 were markedly elevated in septic shock patients, whereas these sCAMs, except for sP-selectin, were within normal ranges in traumatic-hemorrhagic shock patients. In patients with severe sepsis, an earlier stage than septic shock in the sepsis continuum, intermediate values of sCAMs were found. In skin biopsies of septic shock patients, the endothelial cells expressed a bright staining of constitutive endothelial molecules (CD146, CD144, CD131). Inducible molecules (ICAM-1, VCAM-1, and E-selectin) were positively expressed with bright staining. The biopsies from traumatic-hemorrhagic shock patients showed a similar positive expression of endothelial molecules.

CONCLUSION

The patterns of sCAMs indicate that the systemic activation of the endothelium is different in the three clinical entities, maximum in septic shock, intermediate in severe sepsis, and not different from controls in traumatic-hemorrhagic shock. Comparable endothelial activation as evidenced by skin biopsies suggests that caution is required in the interpretation of CAMs in plasma, which does not necessarily reflect the in situ activation state of endothelium.

Plasma transforming growth factor-beta1 level and efficacy of alpha-tocopherol in patients with non-alcoholic steatohepatitis: a pilot study

BACKGROUND

Non-alcoholic steatohepatitis is a distinct entity, characterized by fatty change, lobular inflammation and fibrosis of the liver. Some cases of non-alcoholic steatohepatitis progress to cirrhosis, but it is not easy to distinguish this disease from non-alcoholic fatty liver by non-invasive examinations. No proven therapy for non-alcoholic steatohepatitis exists. Transforming growth factor-beta1 is implicated in the development of liver fibrosis, and is inhibited by alpha-tocopherol (vitamin E) in the liver. Therefore, in this study, the significance of the measurement of the level of plasma transforming growth factor-beta1 and the effect of alpha-tocopherol on the clinical course of non-alcoholic steatohepatitis were investigated.

METHODS

Twelve patients with non-alcoholic steatohepatitis and 10 patients with non-alcoholic fatty liver, with a diagnosis confirmed by liver biopsy, were studied. None of the patients had a history of alcohol abuse, habitual medicine or malignant or inflammatory diseases. All patients were negative for hepatitis B, C and G virus. Patients were given dietary instruction for 6 months, and then alpha-tocopherol (300 mg/day) was given for 1 year. Blood chemistries, measurement of plasma transforming growth factor-beta1 level and liver biopsies were undertaken before and after the 1-year alpha-tocopherol treatment.

RESULTS

The serum alanine transaminase level decreased in non-alcoholic fatty liver patients, but not in non-alcoholic steatohepatitis patients, after 6 months of dietary therapy. Although the serum alanine transaminase level in non-alcoholic steatohepatitis patients was reduced during the 1-year alpha-tocopherol treatment, alpha-tocopherol had no effect on the serum alanine transaminase level in non-alcoholic fatty liver patients. The histological findings, such as steatosis, inflammation and fibrosis, of the non-alcoholic steatohepatitis patients were improved after alpha-tocopherol treatment. The plasma transforming growth factor-beta1 level in non-alcoholic steatohepatitis patients was significantly elevated compared with that in non-alcoholic fatty liver patients and healthy controls, and decreased, accompanied by an improvement in serum alanine transaminase level, with alpha-tocopherol treatment.

CONCLUSIONS

Our data suggest that the measurement of the level of plasma transforming growth factor-beta1 represents a possible method of distinguishing between non-alcoholic steatohepatitis and non-alcoholic fatty liver. Long-term alpha-tocopherol treatment may be safe and effective for non-alcoholic steatohepatitis. A randomized, controlled, double-blind trial is needed to confirm the full potential of alpha-tocopherol in the management of non-alcoholic steatohepatitis.

Role of interleukin-10 in monocyte hyporesponsiveness associated with septic shock

OBJECTIVES

The purpose of this study was to examine the pattern of tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 release in endotoxin-stimulated septic monocytes and to determine the role of IL-10 and transforming growth factor (TGF)-beta in monocyte hyporesponsiveness during septic shock.

DESIGN

Monocytes isolated from ten healthy controls and ten patients with septic shock were incubated with endotoxin and cytokine release was assessed. Next, normal monocytes were incubated with either normal or septic serum and stimulated with endotoxin. Finally, normal monocytes were incubated with septic serum either with anti-IL-10 antibodies or anti-TGF-beta antibodies and then stimulated with endotoxin.

MEASUREMENTS

TNF-alpha, IL-10, and TGF-beta levels were measured in the serum and in culture supernatants by enzyme-linked immunosorbent assay.

SETTING

Research laboratory.

MAIN RESULTS

IL-10 and TNF-alpha levels were significantly increased in septic serum, whereas TGF-beta levels were not different from controls. Normal monocytes increased TNF-alpha and IL-10 release in response to endotoxin. In contrast, septic monocyte TNF-alpha release was attenuated in response to endotoxin (1.8 +/- 0.5 vs. 1.0 +/- 0.4 ng/mL, stimulated vs. baseline), whereas IL-10 release increased significantly from baseline (173 +/- 91 vs. 8 +/- 4 pg/mL, stimulated vs. baseline). Incubation of normal monocytes with septic serum attenuated TNF-alpha release in response to endotoxin (32% +/- 8% of normal serum; p < .01), whereas IL-10 release was increased (285% +/- 84% of normal serum; p < .05). When normal monocytes were incubated with septic serum combined with anti-IL-10 antibodies, TNF-alpha release increased significantly to 75% +/- 17% of normal serum (p < .05 vs. septic serum alone). Incubation of normal monocytes with anti-TGF-beta antibodies did not significantly affect either TNF-alpha or IL-10 release in response to endotoxin.

CONCLUSION

Monocytes from patients with septic shock exhibit persistent IL-10 release at a time when TNF-alpha release is downregulated. The continued release of IL-10 may contribute to impairment of monocyte proinflammatory cytokine release and the development of immune dysfunction in septic shock.

Macrophage inflammatory protein-1 alpha is a critical mediator of host defense against invasive pulmonary aspergillosis in neutropenic hosts

Invasive pulmonary aspergillosis is a devastating complication of immunosuppression that usually occurs in neutropenic patients. In this setting, augmentation of the antifungal activity of available immune cells may improve the outcome of the infection. Macrophage inflammatory protein-1 alpha (MIP-1 alpha) is a CC chemokine with potent chemotactic activity for various subsets of mononuclear leukocytes. We therefore tested the hypothesis that the influx of mononuclear cells into the lung in invasive pulmonary aspergillosis is in part mediated by MIP-1 alpha, and the manipulation of this ligand alters the outcome of the infection. We found that in both immunocompetent and neutropenic mice, MIP-1 alpha was induced in the lungs in response to intratracheal administration of Aspergillus fumigatus conidia. In neutrophil-depleted mice challenged with intratracheal conidia, there was evidence of invasive fungal pneumonia associated with a predominantly mononuclear leukocyte infiltrate. Ab-mediated depletion of MIP-1 alpha resulted in a 6-fold increase in mortality in neutropenic mice, which was associated with a 12-fold increase in lung fungal burden. Studies of single-cell suspensions of whole lungs revealed a 36% decrease in total lung leukocyte infiltration as a result of MIP-1 alpha neutralization. Flow cytometry on whole lung suspensions showed a 41% reduction in lung monocyte/macrophages as a result of MIP-1 alpha neutralization, but no difference in other lung leukocyte subsets. These studies indicate that MIP-1 alpha is a critical mediator of host defense against A. fumigatus in the setting of neutropenia and may be an important target in devising future therapeutic strategies against invasive aspergillosis.

Neutrophil and endothelial cell interactions in sepsis. The role of adhesion molecules

Although adhesion molecules present on circulating neutrophils and endothelial cells are essential for normal host defense, generalized activation of these molecules has been implicated in the inflammatory tissue injury occurring during sepsis and septic shock. A review of both preclinical and clinical studies suggests, however, that although these molecules mediate tissue injury related to a variety of microbial and host inflammatory mediators, their predominant role during sepsis with infection is a protective one.