Anti-inflammatory therapies to treat sepsis and septic shock: a reassessment

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

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

Sepsis after renal transplantation: Clinical, immunological, and microbiological risk factors

BACKGROUND

As immunosuppressive therapy and allograft survival have improved, the increased incidence of sepsis has become a major hurdle of disease-free survival after renal transplantation.

METHODS

We identified 112 of 957 kidney transplant recipients (KTRs) with sepsis. In all, 31 KTRs developed severe sepsis or septic shock, and 30 KTRs died from sepsis. KTRs without sepsis were used for comparison. CMV-specific and alloreactive T cells were measured using an interferon-γ Elispot assay. The extent of immunosuppression was quantified by lymphocyte subpopulations.

RESULTS

Five-year patient survival was 70.3% with sepsis compared to 88.2% without (P<.001). Five-year estimated glomerular filtration rate was lower in KTRs developing sepsis (P<.001). Upon multivariate analysis, diabetes, lymphocyte-depleting induction, donor age, CMV replication, and acute rejection increased the risk of sepsis (P<.05). Age, diabetes, underweight/obesity, and pneumonia as site of infection were predictive factors of mortality (P<.05). Early-onset sepsis was associated with decreased CD3+ and CD4+ T cells pre-transplantation (P<.05). Impaired CMV-specific cellular immunity pre-transplantation was associated with CMV replication and early-onset sepsis (P<.05). High frequencies of alloreactive T cells were associated with acute rejection, lymphocyte-depleting rejection treatment, and early-onset sepsis (P<.05).

CONCLUSION

KTRs developing sepsis show inferior patient survival and allograft function. Identified risk factors and differences in lymphocyte counts, CMV-specific immunity, and alloreactivity may prove useful to identify KTRs at increased risk.

Impact of thrombosis on pulmonary endothelial injury and repair following sepsis

The prevailing morbidity and mortality in sepsis are largely due to multiple organ dysfunction (MOD), most commonly lung injury, as well as renal and cardiac dysfunction. Despite recent advances in defining many aspects of the pathogenesis of sepsis-related MOD, including acute respiratory distress syndrome (ARDS), there are currently no effective pharmacological or cell-based treatments for the disease. Human and animal studies have shown that pulmonary thrombosis is common in sepsis-induced ARDS, and preclinical studies have shown that anticoagulation may improve outcome following sepsis challenge. The potential beneficial effect of anticoagulation on outcome is unconvincing in clinical studies, however, and these discrepancies may arise from the multiple and sometimes opposing actions of thrombosis on the pulmonary endothelium following sepsis. It has been suggested, for example, that mild pulmonary thrombosis prevents escape of bacterial infection into the circulation, while severe thrombosis causes hypoxia and results in pulmonary endothelial damage. Evidence from both human and animal studies has demonstrated the key role of microvascular leakage in determining the outcome of sepsis. In this review, we describe thrombosis-dependent mechanisms that regulate pulmonary endothelial injury and repair following sepsis, including activation of the coagulation cascade by tissue factor and stimulation of vascular repair by hypoxia-inducible factors. Targeting such mechanisms through anticoagulant, anti-inflammatory, and reparative methods may represent a novel approach for the treatment of septic patients.

The Management of Sepsis: A Practical Review

The incidence of the sepsis syndrome has increased dramatically in the last few decades. During this time we have gained new insights into the pathophysiologic mechanisms leading to organ dysfunction in sepsis and the importance of the host-bacterial interactions in mediating many of these processes. This knowledge has led to new therapeutic approaches and the investigation of a number of novel agents. An assessment of these approaches is presented to aid clinicians in the management of patients with severe sepsis. Criteria used to select studies included their relevance to the management of sepsis and their pertinence to clinicians. Appropriate antibiotic selection and volume resuscitation remain the cornerstone of treatment of septic patients. Hydroxyethyl starch solutions have theoretical advantages over crystalloids; there is, however, no data that the type of resuscitation fluid alters outcome. Vasoactive agents are required in patients who remain hemodynamically unstable or have evidence of tissue hypoxia after adequate volume resuscitation. Although dopamine is widely used, dobutamine and norepinephrine are our vasoactive agents of choice. Dopamine has no proven role in oliguric patients, with early dialysis recommended in patients with acute renal failure. The preferred method of renal replacement therapy remains to be determined. Blood products should be used cautiously in patients with disseminated intravascular coagulation. Therapeutic strategies that interfere with the immune system have not been proven to improve the outcome in unselected groups of patients. However, immunomodulation may prove to have a role in select subgroups of patients. Antibiotic therapy and intensive physiological support continues to be the main approach to the management of patients with severe sepsis. Despite the development of numerous novel therapeutic agents, these drugs have not been demonstrated to improve patient outcome.

Critical Care Medicine: Major Changes in Dogma of the Past Decade

Critical care medicine is a young specialty that has experienced an expansion of research efforts in the last decade. Many physiologic and therapeutic principles or “dogmas” have been challenged, resulting in major “shifts” and minor “drifts” in thinking. This article reviews the available literature about some of these important and sometimes controversial changes, with emphasis on the practical implications of the concepts. Specific areas discussed include supply-dependent oxygen consumption in critical illness, manipulation of the cytokine cascade in sepsis, ventilation in the acute respiratory distress syndrome (ARDS), blood transfusion in the critically ill, the concept of the multiple organ dysfunction syndrome (MODS), the need for nutritional support in the critically ill, and others. Many of the changes discussed involve the recognition that the host response to a severe insult is exceedingly complex, and the understanding of this response and the effects of it at a tissue and cellular level are incomplete. As a result, the ability to impact the outcome of sepsis and MODS has thus far been disappointing, with the possible exception of “lung-protective” ventilation. The final challenge in critical care medicine is to gain information that will allow the practitioner to better understand, prevent, and treat the complex events that result in organ and cellular dysfunction. Future changes in dogma are welcome if they help achieve these goals.

Immune-responsiveness of CD4+ T cells during Streptococcus suis serotype 2 infection

The pathogenesis of Streptococcus suis infection, a major swine and human pathogen, is only partially understood and knowledge on the host adaptive immune response is critically scarce. Yet, S. suis virulence factors, particularly its capsular polysaccharide (CPS), enable this bacterium to modulate dendritic cell (DC) functions and potentially impair the immune response. This study aimed to evaluate modulation of T cell activation during S. suis infection and the role of DCs in this response. S. suis-stimulated total mouse splenocytes readily produced TNF-α, IL-6, IFN-γ, CCL3, CXCL9, and IL-10. Ex vivo and in vivo analyses revealed the involvement of CD4⁺ T cells and a Th1 response. Nevertheless, during S. suis infection, levels of the Th1-derived cytokines TNF-α and IFN-γ were very low. A transient splenic depletion of CD4⁺ T cells and a poor memory response were also observed. Moreover, CD4⁺ T cells secreted IL-10 and failed to up-regulate optimal levels of CD40L and CD69 in coculture with DCs. The CPS hampered release of several T cell-derived cytokines in vitro. Finally, a correlation was established between severe clinical signs of S. suis disease and impaired antibody responses. Altogether, these results suggest S. suis interferes with the adaptive immune response.

Emerging infection and sepsis biomarkers: will they change current therapies?

INTRODUCTION

Sepsis is a heterogeneous syndrome characterized by both immune hyperactivity and relative immune suppression. Biomarkers have the potential to improve recognition and management of sepsis through three main applications: diagnosis, monitoring response to treatment, and stratifying patients based on prognosis or underlying biological response.

AREAS COVERED

This review focuses on specific examples of well-studied, evidence-supported biomarkers, and discusses their role in clinical practice with special attention to antibiotic stewardship and cost-effectiveness. Biomarkers were selected based on availability of robust prospective trials and meta-analyses which supported their role as emerging tools to improve the clinical management of sepsis. Expert commentary: Great strides have been made in candidate sepsis biomarker discovery and testing, with the biomarkers in this review showing promise. Yet sepsis remains a dynamic illness with a great degree of biological heterogeneity - heterogeneity which may be further resolved by recently discovered gene expression-based endotypes in septic shock.

Humanized mice in infectious diseases

The pathogenesis of infectious agents with human tropism can only be properly studied in an in vivo model featuring human cells or tissue. Humanized mice represent a small animal model featuring human cells or tissue that can be infected by human-specific viruses, bacteria, and parasites and also providing a functional human immune system. This makes the analysis of a human immune response to infection possible and allows for preclinical testing of new vaccines and therapeutic agents. Results of various studies using humanized mice to investigate pathogens with human tropism are presented in this review. In addition, the limitations of humanized mice and methods to improve this valuable animal model are discussed.

Targeting ADAM17 in leukocytes increases neutrophil recruitment and reduces bacterial spread during polymicrobial sepsis

A rapid and robust recruitment of circulating neutrophils at sites of infection is critical for preventing bacterial spread. The efficiency of this process, however, is greatly diminished during sepsis, a severe systemic inflammatory response to infection. The proteolytic activity of a disintegrin and metalloprotease-17 is induced in the cell membrane of leukocytes upon their activation, resulting in the conversion of membrane to soluble TNF-α and the release of assorted receptors from the surface of neutrophils important for their effector functions. We show that conditional knockout mice lacking a disintegrin and metalloprotease-17 in all leukocytes had a survival advantage when subjected to polymicrobial sepsis. Bacteremia and the levels of circulating proinflammatory cytokines, key determinants of sepsis severity, were significantly reduced in conditional a disintegrin and metalloprotease-17 knockout mice during sepsis. Although cecal bacterial microbiota and load were similar in unmanipulated conditional a disintegrin and metalloprotease-17 knockout and control mice, peritoneal spread of bacteria was significantly reduced in conditional a disintegrin and metalloprotease-17 knockout mice following sepsis induction, which was associated with an amplified recruitment of neutrophils. Taken together, our findings suggest that extensive a disintegrin and metalloprotease-17 induction during sepsis may tip the balance between efficient and impaired neutrophil recruitment.

Dietary Apigenin Exerts Immune-Regulatory Activity in Vivo by Reducing NF-κB Activity, Halting Leukocyte Infiltration and Restoring Normal Metabolic Function

The increasing prevalence of inflammatory diseases and the adverse effects associated with the long-term use of current anti-inflammatory therapies prompt the identification of alternative approaches to reestablish immune balance. Apigenin, an abundant dietary flavonoid, is emerging as a potential regulator of inflammation. Here, we show that apigenin has immune-regulatory activity in vivo. Apigenin conferred survival to mice treated with a lethal dose of Lipopolysaccharide (LPS) restoring normal cardiac function and heart mitochondrial Complex I activity. Despite the adverse effects associated with high levels of splenocyte apoptosis in septic models, apigenin had no effect on reducing cell death. However, we found that apigenin decreased LPS-induced apoptosis in lungs, infiltration of inflammatory cells and chemotactic factors’ accumulation, re-establishing normal lung architecture. Using NF-κB luciferase transgenic mice, we found that apigenin effectively modulated NF-κB activity in the lungs, suggesting the ability of dietary compounds to exert immune-regulatory activity in an organ-specific manner. Collectively, these findings provide novel insights into the underlying immune-regulatory mechanisms of dietary nutraceuticals in vivo.

Reducing acute respiratory distress syndrome occurrence using mechanical ventilation

The standard treatment for acute respiratory distress syndrome (ARDS) is supportive in the form of low tidal volume ventilation applied after significant lung injury has already developed. Nevertheless, ARDS mortality remains unacceptably high (> 40%). Indeed, once ARDS is established it becomes refractory to treatment, and therefore avoidance is key. However, preventive techniques and therapeutics to reduce the incidence of ARDS in patients at high-risk have not been validated clinically. This review discusses the current data suggesting that preemptive application of the properly adjusted mechanical breath can block progressive acute lung injury and significantly reduce the occurrence of ARDS.

[Microarrays as biomarkers in trauma]

BACKGROUND

The traditional hypothesis-driven scientific approach cannot so far sufficiently elucidate complex pathophysiologies, such as posttraumatic systemic inflammation and subsequent multiple organ failure. This complex system includes different biological and functional levels, the genome, the transcriptome, the proteome, the biome (cells), the organs and finally the whole organism.

METHODS

Microarray techniques enable a simultaneous search for these different biological levels and their functional relationships on a large scale and to discover new functional pathways and networks and potentially new biomarkers for different pathologies. Microarray technologies lead to a new paradigm in science, the hypothesis-generating approach.

AIM

This article reviews important microarray findings in trauma and systemic inflammation research and discusses potentials and limitations of these biotechnological screening methods.

Biomarkers of Endothelial Activation Are Associated with Poor Outcome in Critical Illness

Background

Endothelial activation plays a role in organ dysfunction in the systemic inflammatory response syndrome (SIRS). Angiopoietin-1 (Ang-1) promotes vascular quiescence while angiopoietin-2 (Ang-2) mediates microvascular leak. Circulating levels of Ang-1 and Ang-2 in patients with SIRS could provide insight on risks for organ dysfunction and death distinct from inflammatory proteins. In this study, we determined if biomarkers of endothelial activation and inflammation exhibit independent associations with poor outcomes in SIRS.

Methods

We studied 943 critically ill patients with SIRS admitted to an Intensive Care Unit (ICU) of an academic medical center. We measured plasma levels of endothelial markers (Ang-1, Ang-2, soluble vascular cell adhesion molecule-1 (sVCAM-1)) and inflammatory markers (interleukin-6 (IL-6), interleukin-8 (IL-8), granulocyte-colony stimulating factor (G-CSF), soluble tumor necrosis factor receptor-1 (sTNFR-1)) within 24 hours of enrollment. We tested for associations between each marker and 28 day mortality, shock, and day 3 sequential organ failure assessment (SOFA) score. For 28 day mortality, we performed sensitivity analysis for those subjects with sepsis and those with sterile inflammation. We used multivariate models to adjust for clinical covariates and determine if associations identified with endothelial activation markers were independent of those observed with inflammatory markers.

Results

Higher levels of all biomarkers were associated with increased 28 day mortality except levels of Ang-1 which were associated with lower mortality. After adjustment for comorbidities and sTNFR-1 concentration, a doubling of Ang-1 concentration was associated with lower 28 day mortality (Odds ratio (OR) = 0.81; p<0.01), shock (OR = 0.82; p<0.001), and SOFA score (β = -0.50; p<0.001), while Ang-2 concentration was associated with increased mortality (OR = 1.55; p<0.001), shock (OR = 1.51; p<0.001), and SOFA score (β = +0.63; p<0.001). sVCAM-1 was not independently associated with SIRS outcomes.

Conclusions

In critically ill patients with SIRS, early measurements of Ang-1 and Ang-2 are associated with death and organ dysfunction independently of simultaneously-measured markers of inflammation.

Treatment of Experimental Candida Sepsis with a Janus Kinase Inhibitor Controls Inflammation and Prolongs Survival

Janus kinases (JAK) are intracellular tyrosine kinases that transduce cytokine-mediated signals to the nucleus, promoting gene expression. Cytokines play a major role in microbial sepsis, which is often associated with uncontrolled inflammation leading to death. JAK inhibitors have been used for the treatment of several autoimmune diseases by modulating immune response, but they have never been tested against microbial sepsis. Ruxolitinib is a small-molecule inhibitor of JAK1/2 proteins, which are involved in the downstream signaling pathway of the vast majority of proinflammatory and anti-inflammatory cytokines. We therefore studied the effect of ruxolitinib in a mouse model of sepsis due to Candida albicans. When ruxolitinib therapy (50 mg/kg [of body weight]/day) was started 1 day before infection, the median survival time was reduced by 3 days, the fungal loads in all organs were higher, the inflammation was significantly less, and serum tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10) levels and IL-10/TNF-α ratios were higher than in controls. When ruxolitinib therapy (50 to 1.5 mg/kg/day) was started 1 day after infection, an inverted-U relationship was found, with 6.25 mg/kg/day prolonging median survival time by 6 days, resulting in similar fungal loads, less inflammation, and similar cytokine levels but higher IL-10/TNF-α ratios than the controls. The optimal dose of ruxolitinib controlled infection and prolonged survival with less inflammation than in control animals. Administration of JAK inhibitors may be a promising therapeutic adjunct that needs further investigation.

Complexity and forensic pathology

It has become increasingly apparent that nonlinearity and complexity are the norm in human physiological systems, the relevance of which is informing an enhanced understanding of basic pathological processes such as inflammation, the host response to severe trauma, and critical illness. This article will explore how an understanding of nonlinear systems and complexity might inform the study of the pathophysiology of deaths of medicolegal interest, and how 'complexity thinking' might usefully be incorporated into modern forensic medicine and forensic pathology research, education and practice.

Monocyte Tumor Necrosis Factor-α-Converting Enzyme Catalytic Activity and Substrate Shedding in Sepsis and Noninfectious Systemic Inflammation

Objectives:

To determine the effect of severe sepsis on monocyte tumor necrosis factor-α–converting enzyme baseline and inducible activity profiles.

Design:

Observational clinical study.

Setting:

Mixed surgical/medical teaching hospital ICU.

Patients:

Sixteen patients with severe sepsis, 15 healthy volunteers, and eight critically ill patients with noninfectious systemic inflammatory response syndrome.

Interventions:

None.

Measurements and Main Results:

Monocyte expression of human leukocyte antigen-D-related peptide, sol-tumor necrosis factor production, tumor necrosis factor-α–converting enzyme expression and catalytic activity, tumor necrosis factor receptor 1 and 2 expression, and shedding at 48-hour intervals from day 0 to day 4, as well as p38-mitogen activated protein kinase expression. Compared with healthy volunteers, both sepsis and systemic inflammatory response syndrome patients’ monocytes expressed reduced levels of human leukocyte antigen-D-related peptide and released less sol-tumor necrosis factor on in vitro lipopolysaccharide stimulation, consistent with the term monocyte deactivation. However, patients with sepsis had substantially elevated levels of basal tumor necrosis factor-α–converting enzyme activity that were refractory to lipopolysaccharide stimulation and this was accompanied by similar changes in p38-mitogen activated protein kinase signaling. In patients with systemic inflammatory response syndrome, monocyte basal tumor necrosis factor-α–converting enzyme, and its induction by lipopolysaccharide, appeared similar to healthy controls. Changes in basal tumor necrosis factor-α–converting enzyme activity at day 0 for sepsis patients correlated with Acute Physiology and Chronic Health Evaluation II score and the attenuated tumor necrosis factor-α–converting enzyme response to lipopolysaccharide was associated with increased mortality. Similar changes in monocyte tumor necrosis factor-α–converting enzyme activity could be induced in healthy volunteer monocytes using an in vitro two-hit inflammation model. Patients with sepsis also displayed reduced shedding of monocyte tumor necrosis factor receptors upon stimulation with lipopolysaccharide.

Conclusions:

Monocyte tumor necrosis factor-α–converting enzyme catalytic activity appeared altered by sepsis and may result in reduced shedding of tumor necrosis factor receptors. Changes seemed specific to sepsis and correlated with illness severity. A better understanding of how tumor necrosis factor-α–converting enzyme function is altered during sepsis will enhance our understanding of sepsis pathophysiology, which will help in the assessment of patient inflammatory status and ultimately may provide new strategies to treat sepsis.

Current controversies in the support of sepsis

PURPOSE OF REVIEW

Sepsis has a high morbidity, with a mortality rate of over 50% in the septic shock patient. This review provides a comprehensive summary of the latest Surviving Sepsis Campaign and the recent evidence since its publication. The guidelines reflect literature from the past 5 years to optimize outcomes in patients with severe sepsis and septic shock.

RECENT FINDINGS

The most relevant changes in the latest Surviving Sepsis Campaign include the use of a protocolized resuscitation with specific physiologic targets, preference of crystalloids for volume resuscitation, preferential use of norepinephrine as the initial vasopressor, addition of lactate and its clearance as a marker of tissue hypoperfusion, reduced emphasis on corticosteroids, and removal of activated protein C therapy. Since these latest guidelines, there have been many trials published to address the various measures that are advocated. We review the recent data on fluid resuscitation, targets of resuscitation, vasopressors, and trials of protocolized care versus usual care.

SUMMARY

Severe sepsis remains a significant cause of morbidity and mortality in hospitalized patients. The International Surviving Sepsis Guidelines provide a framework for early recognition and treatment of this condition, with the goal of an improved outcome and mortality in severe sepsis. The recent evidence suggests that early identification, adequate volume resuscitation, and assessment of adequate circulation may be the key elements to decrease morbidity from severe sepsis and septic shock.

Insight into the beneficial immunomodulatory mechanism of the sevoflurane metabolite hexafluoro-2-propanol in a rat model of endotoxaemia

Volatile anaesthetics such as sevoflurane attenuate inflammatory processes, thereby impacting patient outcome significantly. Their inhalative administration is, however, strictly limited to controlled environments such as operating theatres, and thus an intravenously injectable immunomodulatory drug would offer distinct advantages. As protective effects of volatile anaesthetics have been associated with the presence of trifluorinated carbon groups in their basic structure, in this study we investigated the water-soluble sevoflurane metabolite hexafluoro-2-propanol (HFIP) as a potential immunomodulatory drug in a rat model of endotoxic shock. Male Wistar rats were subjected to intravenous lipopolysaccharide (LPS) and thereafter were treated with HFIP. Plasma and tissue inflammatory mediators, neutrophil invasion, tissue damage and haemodynamic stability were the dedicated end-points. In an endotoxin-induced endothelial cell injury model, underlying mechanisms were elucidated using gene expression and gene reporter analyses. HFIP reduced the systemic inflammatory response significantly and decreased endotoxin-induced tissue damage. Additionally, the LPS-provoked drop in blood pressure of animals was resolved by HFIP treatment. Pathway analysis revealed that the observed attenuation of the inflammatory process was associated with reduced nuclear factor kappa B (NF-κΒ) activation and suppression of its dependent transcripts. Taken together, intravenous administration of HFIP exerts promising immunomodulatory effects in endotoxaemic rats. The possibility of intravenous administration would overcome limitations of volatile anaesthetics, and thus HFIP might therefore represent an interesting future drug candidate for states of severe inflammation.

Genipin attenuates sepsis-induced immunosuppression through inhibition of T lymphocyte apoptosis

Sepsis, a systemic inflammatory response to infection, initiates a complex immune response consisting of an early hyperinflammatory response and a subsequent hypoinflammatory response that impairs the removal of infectious organisms. The importance of sepsis-induced immunosuppression and its contribution to mortality has recently emerged. Apoptotic depletion of T lymphocytes is a critical cause of immunosuppression in the late phase of sepsis. Genipin is a major active compound of gardenia fruit that has anti-apoptotic and anti-microbial properties. This study investigated the mechanisms of action of genipin on immunosuppression in the late phase of sepsis. Mice received genipin (1, 2.5 and 5mg/kg, i.v.) at 0 (immediately) and 24h after cecal ligation and puncture (CLP). Twenty-six hours after CLP, the spleen and blood were collected. Genipin improved the survival rate compared to controls. CLP increased the levels of FADD, caspase-8 and caspase-3 protein expression, which were attenuated by genipin. Genipin increased the level of anti-apoptotic B-cell lymphoma-2 protein expression, while it decreased the level of pro-apoptotic phosphorylated-Bim protein expression in CLP. CLP decreased the CD4(+) and CD8(+) T cell population, while it increased the regulatory T cell (Treg) population and the level of cytotoxic T lymphocyte-associated antigen 4 protein expression on Treg. These changes were attenuated by genipin. The splenic levels of interferon-γ and interleukin (IL)-2 were reduced, while the levels of IL-4 and IL-10 increased after CLP. Genipin attenuated these alterations. These findings suggest that genipin reduces immunosuppression by inhibiting T lymphocyte apoptosis in the late phase of sepsis.

Propofol increases morbidity and mortality in a rat model of sepsis

INTRODUCTION

Severe sepsis is associated with approximately 50% mortality and accounts for tremendous healthcare costs. Most patients require ventilatory support and propofol is commonly used to sedate mechanically ventilated patients. Volatile anesthetics have been shown to attenuate inflammation in a variety of different settings. We therefore hypothesized that volatile anesthetic agents may offer beneficial immunomodulatory effects during the course of long-term intra-abdominal sepsis in rats under continuous sedation and ventilation for up to 24 hours.

METHODS

Sham operation or cecal ligation and puncture (CLP) was performed in adult male Wistar rats followed by mechanical ventilation. Animals were sedated for 24 hours with propofol (7 to 20 mg/kg/h), sevoflurane, desflurane or isoflurane (0.7 minimal alveolar concentration each).

RESULTS

Septic animals sedated with propofol showed a mean survival time of 12 hours, whereas >56% of all animals in the volatile groups survived 24 hours (P <0.001). After 18 hours, base excess in propofol + CLP animals (-20.6 ± 2.0) was lower than in the volatile groups (isoflurane + CLP: -11.7 ± 4.2, sevoflurane + CLP: -11.8 ± 3.5, desflurane + CLP -14.2 ± 3.7; all P <0.03). Plasma endotoxin levels reached 2-fold higher levels in propofol + CLP compared to isoflurane + CLP animals at 12 hours (P <0.001). Also blood levels of inflammatory mediators (tumor necrosis factor-α, interleukin-1β, interleukin-10, CXCL-2, interferon-γ and high mobility group protein-1) were accentuated in propofol + CLP rats compared to the isoflurane + CLP group at the same time point (P <0.04).

CONCLUSIONS

This is the first study to assess prolonged effects of sepsis and long-term application of volatile sedatives compared to propofol on survival, cardiovascular, inflammatory and end organ parameters. Results indicate that volatile anesthetics dramatically improved survival and attenuate systemic inflammation as compared to propofol. The main mechanism responsible for adverse propofol effects could be an enhanced plasma endotoxin concentration, leading to profound hypotension, which was unresponsive to fluid resuscitation.

8,8'-Bieckol, isolated from edible brown algae, exerts its anti-inflammatory effects through inhibition of NF-κB signaling and ROS production in LPS-stimulated macrophages

Ecklonia cava (E. cava) is an abundant brown alga that contains high levels of phlorotannins, which are unique marine polyphenolic compounds. It has been suggested that E. cava phlorotannins exert anti-inflammatory effects. However, the anti-inflammatory effects and underlying molecular mechanism exerted by 8,8'-bieckol isolated from E. cava have not been reported. Thus, in this study, we examined the anti-inflammatory effects of 8,8'-bieckol on lipopolysaccharide (LPS)-stimulated primary macrophages and RAW 264.7 macrophages. We found that 8,8'-bieckol suppressed key inflammatory mediator [i.e., nitric oxide (NO) and prostaglandin E2 (PGE2)] production in both primary and RAW 264.7 macrophages. 8,8'-Bieckol inhibited NO by suppressing LPS-induced expression of inducible nitric oxide synthase (iNOS) at the mRNA and protein levels in primary macrophages and RAW 264.7 cells. In addition, 8,8'-bieckol decreased the production and mRNA expression of the inflammatory cytokine interleukin-6 (IL-6), but not tumor necrosis factor (TNF)-α, in RAW 264.7 cells. Moreover, 8,8'-bieckol treatment diminished transactivation of nuclear factor-kappa B (NF-κB) and nuclear translocation of the NF-κB p65 subunit and suppressed LPS-induced intracellular reactive oxygen species (ROS) production in macrophages. Furthermore, 8,8'-bieckol markedly reduced mortality in LPS-induced septic mice. Taken together, these data indicate that the anti-inflammatory properties of 8,8'-bieckol are associated with the suppression of NO, PGE2, and IL-6 via negative regulation of the NF-κB pathway and ROS production in LPS-stimulated RAW 264.7 cells. Moreover, 8,8'-bieckol protects mice from endotoxin shock.

Aldosterone secretion in patients with septic shock: a prospective study

OBJECTIVE

To assess serum levels of the main factors that regulate the activation of the zona glomerulosa and aldosterone production in patients with septic shock, as well as their response to a high-dose (250 µg) adrenocorticotropic hormone (ACTH) stimulation test.

SUBJECTS AND METHODS

In 27 patients with septic shock, baseline levels of aldosterone, cortisol, ACTH, renin, sodium, potassium, and lactate were measured, followed by a cortrosyn test.

RESULTS

Renin correlated with baseline aldosterone and its variation after cortrosyn stimulation. Baseline cortisol and its variation did not correlate with ACTH. Only three patients had concomitant dysfunction of aldosterone and cortisol secretion.

CONCLUSIONS

Activation of the zona glomerulosa and zona fasciculata are independent. Aldosterone secretion is dependent on the integrity of the renin-angiotensin-aldosterone system, whereas cortisol secretion does not appear to depend predominantly on the hypothalamic-pituitary-adrenal axis. These results suggest that activation of the adrenal gland in critically ill patients occurs by multiple mechanisms.

Neutrophils with myeloid derived suppressor function deplete arginine and constrain T cell function in septic shock patients

Introduction

Impaired T cell function in sepsis is associated with poor outcome, but the mechanisms are unclear. In cancer, arginase-expressing myeloid derived suppressor cells (MDSCs) deplete arginine, impair T cell receptor CD3 zeta-chain expression and T cell function and are linked to poor clinical outcome, but their role during acute human infectious disease and in particular sepsis remains unknown. Hypoarginemia is prevalent in sepsis. This study aimed to determine whether neutrophils that co-purify with PBMC express arginase, and if arginine depletion constrains T cell CD3 zeta-chain expression and function in human sepsis.

Methods

Using flow cytometry, cell culture, HPLC, arginase activity and mRNA detection, our study examined whether neutrophils, with reduced buoyant density isolated in the Ficoll interface, metabolise L-arginine and suppress T cell proliferation in sepsis. A total of 35 sepsis patients (23 with septic shock) and 12 hospital controls in a tertiary referral hospital in tropical Australia were evaluated.

Results

Only sepsis patients had interphase neutrophils, neutrophils co-purifying with mononuclear cells (≤1.077 specific gravity). The percentage of interphase neutrophils in sepsis was proportional to sepsis severity and correlated with plasma IL-6 concentrations. Ex vivo, sepsis-derived interphase neutrophils expressed arginase, metabolised culture L-arginine and suppressed T cell proliferation and CD3 zeta-chain expression. In vivo, in septic shock there was a longitudinal inverse association between interphase neutrophil number and CD3 zeta-chain expression. Depletion or inhibition of interphase neutrophils in vitro restored zeta-chain expression and T cell function.

Conclusions

For the first time during an acute human infection, interphase neutrophils that express arginase were found to circulate in sepsis, in proportion to disease severity. These neutrophil-MDSCs impair T cell CD3 zeta-chain expression and T cell function via L-arginine metabolism, and likely contribute to the T cell dysfunction seen in sepsis. Modulation of neutrophil-MDSC or their downstream effects warrant consideration as targets for novel adjunctive therapies in sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/cc14003) contains supplementary material, which is available to authorized users.

Immunomodulatory adjuvant therapy in severe community-acquired pneumonia

Severe pneumonia has a high mortality (38.2%) despite evidence-based therapy. Rising rates of antimicrobial resistance increase the urgency to develop new treatment strategies. Multiple adjuvant therapies for pneumonia have been investigated but none are currently licensed. Profound immune dysregulation occurs in patients with severe infection. An initial hyper-inflammatory response is followed by a secondary hypo-inflammatory response with 'immune-paralysis'. There is focus on the development of immunostimulatory agents to improve host ability to combat primary infection and reduce secondary infections. Successful treatments must be targeted to immune response; promising biomarkers exist but have not yet reached common bedside practice. We explore evidence for adjuvant therapies in community-acquired pneumonia. We highlight novel potential treatment strategies using a broad-based search strategy to include publications in pneumonia and severe sepsis. We explore reasons for the failure to develop effective adjuvant therapies and highlight the need for targeted therapy specific to immune activity.

Chloral hydrate-dependent reduction in the peptidoglycan-induced inflammatory macrophage response is associated with lower expression levels of toll-like receptor 2

The aim of this study was to investigate the effect and mechanism of action of chloral hydrate on the peptidoglycan (PGN)-induced inflammatory macrophage response. The effect of chloral hydrate on the production of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) by murine peritoneal macrophages with PGN-stimulation was investigated. In addition, RAW264.7 cells transfected with a nuclear factor-κB (NF-κB) luciferase reporter plasmid stimulated by PGN were used to study the effect of chloral hydrate on the levels NF-κB activity. Flow cytometry and western blotting were performed to investigate the expression levels of toll-like receptor 2 (TLR2) in the treated RAW264.7 cells. It was identified that chloral hydrate reduced the levels of IL-6 and TNF-α produced by the peritoneal macrophages stimulated with PGN. The levels of NF-κB activity of the RAW264.7 cells stimulated by PGN decreased following treatment with chloral hydrate, which was associated with a reduction in the expression levels of TLR2 and reduced levels of TLR2 signal transduction. These data demonstrate that chloral hydrate reduced the magnitude of the PGN-induced inflammatory macrophage response associated with lower expression levels of TLR2.

Endogenous Tetrapyrroles Influence Leukocyte Responses to Lipopolysaccharide in Human Blood: Pre-Clinical Evidence Demonstrating the Anti-Inflammatory Potential of Biliverdin

Sepsis is associated with abnormal host immune function in response to pathogen exposure, including endotoxin (lipopolysaccharide; LPS). Cytokines play crucial roles in the induction and resolution of inflammation in sepsis. Therefore, the primary aim of this study was to investigate the effects of endogenous tetrapyrroles, including biliverdin (BV) and unconjugated bilirubin (UCB) on LPS-induced cytokines in human blood. Biliverdin and UCB are by products of haem catabolism and have strong cytoprotective, antioxidant and anti-inflammatory effects. In the present study, whole human blood supplemented with BV and without was incubated in the presence or absence of LPS for 4 and 8 hours. Thereafter, whole blood was analysed for gene and protein expression of cytokines, including IL-1β, IL-6, TNF, IFN-γ, IL-1Ra and IL-8. Biliverdin (50 μM) significantly decreased the LPS-mediated gene expression of IL-1β, IL-6, IFN-γ, IL-1Ra and IL-8 (P<0.05). Furthermore, BV significantly decreased LPS-induced secretion of IL-1β and IL-8 (P<0.05). Serum samples from human subjects and, wild type and hyperbilirubinaemic Gunn rats were also used to assess the relationship between circulating bilirubin and cytokine expression/production. Significant positive correlations between baseline UCB concentrations in human blood and LPS-mediated gene expression of IL-1β (R=0.929), IFN-γ (R=0.809), IL-1Ra (R=0.786) and IL-8 (R=0.857) were observed in blood samples (all P<0.05). These data were supported by increased baseline IL-1β concentrations in hyperbilirubinaemic Gunn rats (P<0.05). Blood samples were also investigated for complement receptor-5 (C5aR) expression. Stimulation of blood with LPS decreased gene expression of C5aR (P<0.05). Treatment of blood with BV alone and in the presence of LPS tended to decrease C5aR expression (P=0.08). These data indicate that supplemented BV inhibits the ex vivo response of human blood to LPS. Surprisingly, however, baseline UCB was associated with heighted inflammatory response to LPS. This is the first study to explore the effects of BV in a preclinical human model of inflammation and suggests that BV could represent an anti-inflammatory target for the prevention of LPS mediated inflammation in vivo.

Systemic inflammatory response syndrome (SIRS): where did it come from and is it still relevant today?

The concept of a systemic inflammatory response syndrome (SIRS) to describe the complex pathophysiologic response to an insult such as infection, trauma, burns, pancreatitis, or a variety of other injuries came from a 1991 consensus conference charged with the task of developing an easy-to-apply set of clinical parameters to aid in the early identification of potential candidates to enter into clinical trials to evaluate new treatments for sepsis. There was recognition that a diverse group of injuries produced a common inflammatory response in the host and provided attractive targets for new anti-inflammatory molecules designed to prevent further propagation and/or provide specific treatment. Effective application of these new anti-inflammatory strategies necessitated identification of early clinical markers that could be assessed in real-time and were likely to define a population of patients that would have a beneficial response to the targeted intervention. It was felt that early clinical manifestations might be more readily available to clinicians than more sophisticated and specific assays for inflammatory substances that were systemically released by the network of injurious inflammatory events. Therefore, the early definition of a systemic inflammatory response syndrome (SIRS) was built upon a foundation of basic clinical and laboratory abnormalities that were readily available in almost all clinical settings. With further refinement, it was hoped, that this definition would have a high degree of sensitivity, coupled with a reasonable degree of specificity. This manuscript reviews the derivation, application, utilization, potential benefits, and speculation regarding the future of the SIRS definition.

Intravenous immunoglobulin for treating sepsis, severe sepsis and septic shock

BACKGROUND

Mortality from sepsis and septic shock remains high. Results of trials on intravenous immunoglobulins (IVIG) as adjunctive therapy for sepsis have been conflicting. This is an update of a Cochrane review that was originally published in 1999 and updated in 2002 and 2010.

OBJECTIVES

To estimate the effects of IVIG as adjunctive therapy in patients with bacterial sepsis or septic shock on mortality, bacteriological failure rates, and duration of stay in hospital.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 6), MEDLINE (1966 to December 2012), and EMBASE (1988 to December 2012). We contacted investigators in the field for unpublished data. The original search was performed in 1999 and updated in 2002 and 2008.

SELECTION CRITERIA

We included randomized controlled trials comparing IVIG (monoclonal or polyclonal) with placebo or no intervention in patients of any age with bacterial sepsis or septic shock.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the studies for inclusion and undertook methodologic quality assessment and data abstraction. We conducted pre-specified subgroup analyses by type of immunoglobulin preparation.

MAIN RESULTS

We included 43 studies that met our inclusion criteria in this updated review out of 88 potentially eligible studies. The studies included a large polyclonal IVIG trial in neonates that was concluded in 2011 and classified as ongoing in the 2010 version of this review. Pooled analysis of polyclonal and monoclonal IVIG was not done due to clinical heterogeneity. Subgroup analysis of 10 polyclonal IVIG trials (n = 1430) and seven trials on IgM-enriched polyclonal IVIG (n = 528) showed significant reductions in mortality in adults with sepsis compared to placebo or no intervention (relative risk (RR) 0.81; 95% confidence interval (CI) 0.70 to 0.93 and RR 0.66; 95% CI 0.51 to 0.85, respectively). Subgroup analysis of polyclonal IVIG in neonates, which now includes the recently concluded large polyclonal IVIG trial, showed no significant reduction in mortality for standard IVIG (RR 1.00; 95% CI 0.92 to 1.08; five trials, n = 3667) and IgM-enriched polyclonal IVIG (RR 0.57; 95% CI 0.31 to 1.04; three trials, n = 164). Sensitivity analysis of trials with low risk of bias showed no reduction in mortality with polyclonal IVIG in adults (RR 0.97; 95% CI 0.81 to 1.15; five trials, n = 945) and neonates (RR 1.01; 95% CI 0.93 to 1.09; three trials, n = 3561). Mortality was not reduced among patients (eight trials, n = 4671) who received anti-endotoxin antibodies (RR 0.99; 95% CI 0.91 to1.06) while anti-cytokines (nine trials, n = 7893) demonstrated a marginal reduction in mortality (RR 0.92; 95% CI 0.86 to 0.97).

AUTHORS' CONCLUSIONS

Polyclonal IVIG reduced mortality among adults with sepsis but this benefit was not seen in trials with low risk of bias. Among neonates with sepsis, there is sufficient evidence that standard polyclonal IVIG, as adjunctive therapy, does not reduce mortality based on the inclusion of the large polyclonal IVIG trial on neonates. For Ig-M enriched IVIG, the trials on neonates and adults were small and the totality of the evidence is still insufficient to support a robust conclusion of benefit. Adjunctive therapy with monoclonal IVIGs remains experimental.

An increased alveolar CD4 + CD25 + Foxp3 + T-regulatory cell ratio in acute respiratory distress syndrome is associated with increased 30-day mortality

Purpose

Cell therapy may become an option for lung injury treatment. However, no data are available on the alveolar presence and time course of CD4+ CD25 + Foxp3 + T-regulatory lymphocyte cells (Tregs) in acute respiratory distress syndrome (ARDS). Accordingly, we (1) measured the ratio of CD4 + CD25 + Foxp3 + Tregs to all (CD4+) lymphocytes in the bronchoalveolar lavage (BAL) of ARDS patients and of control subjects without lung disease and (2) assessed their impact on 30-day mortality.

Methods

In a prospective study, the ratios of CD4 + CD25 + Foxp3 + T-regulatory cells to all CD4+ cells were measured (FACS) within 24 h of the patients’ ICU referral in the BAL and in the blood of 47 patients with ARDS (32 males, 15 females; mean age 44 years ±13) as well as in 8 controls undergoing elective abdominal surgery (5 men, 3 women; mean age 49 years ±4). BAL concentrations of several cytokines were also measured in ARDS patients.

Results

Tregs were detected in the BAL of control subjects and ARDS patients. However, the mean ratio of Tregs to all CD4+ lymphocytes was threefold greater in ARDS non-survivors (16.5 %; p = 0.025) and almost twofold greater in ARDS survivors (9.0 %; p = 0.015) compared to controls (5.9 %). Multivariate Cox regression analysis revealed the ratio of CD4 + CD25 + Foxp3 + T-regulatory lymphocytes to all CD4+ lymphocytes in the BAL to be an important and independent prognostic factor for 30-day survival (HR 6.5; 95 % CI, 1.7–25; p = 0.006).

Conclusion

An increased T-regulatory cell ratio in the admission BAL of patients with ARDS is an important and independent risk factor for 30-day mortality.

Methanol extract of the aerial parts of barley (Hordeum vulgare) suppresses lipopolysaccharide-induced inflammatory responses in vitro and in vivo

CONTEXT

Recently, there has been renewed interest in barley (Hordeum vulgare L. Poaceae) as a functional food and for its medicinal properties.

OBJECTIVE

This study examines the anti-inflammatory potential of the active fractions of barley and the mechanisms involved.

MATERIALS AND METHODS

The macrophages were exposed to 100 μg/mL of each of the barley extracts in the presence of 1 μg/mL lipopolysaccharide (LPS) and after 24 or 48 h of incubation, cells or culture supernatants were analyzed by various assays. The anti-inflammatory potential of barley fractions was also investigated using the LPS-injected septic mouse model. The active constituents in the fractions were identified using gas chromatography-mass spectrometry (GC-MS).

RESULTS

The active fractions, named F₄, F₇, F₉ and F₁₂, inhibited almost completely the LPS-induced production of nitric oxide (NO) and inducible NO synthase. Pre-treatment with these fractions at 100 μg/mL diminished the tumor necrosis factor-α (TNF-α) levels to 19.8, 3.5, 1.2 and 1.7 ng/mL, respectively, compared to LPS treatment alone (41.5 ng/mL). These fractions at 100 μg/mL also suppressed apparently the secretion of interleukin (IL)-6 and IL-1β and the DNA-binding activity of nuclear factor-κB in LPS-stimulated cells. Mice injected intraperitoneally with LPS (30 mg/kg BW) showed 20% survival at 48 h after injection, whereas oral administration of the fractions improved the survival rates to 80%. GC-MS analysis revealed the presence of the derivatives of benzoic and cinnamic acids and fatty acids in the fractions.

DISCUSSION AND CONCLUSION

The aerial parts of barley are useful as functional food to prevent acute inflammatory responses.

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.

CRISPLD2 is expressed at low levels during septic shock and is associated with procalcitonin

Introduction

Previous studies have shown that cysteine-rich secretory protein containing LCCL domain 2 (CRISPLD2) is a novel lipopolysaccharide (LPS)-binding protein, and the upregulation of CRISPLD2 expression protects mice against LPS-induced lethality. The aim of this study was to examine the expression of CRISPLD2 in patients with sepsis and characterize the association of this protein with procalcitonin.

Methods

The expression of CRISPLD2 was determined in100 healthy volunteers and 119 septic patients. According to the definition of sepsis, patients were divided into three groups sepsis, severe sepsis, and septic shock. The relationship between CRISPLD2 levels and procalcitonin was also examined and statistically analyzed.

Results

The CRISPLD2 levels in healthy individuals were 219.3±69.1 µg/ml. Patients with sepsis exhibited higher CRISPLD2 levels than observed in healthy individuals (p = 0.001), but CRISPLD2 expression was not upregulated in patients with septic shock. No significant differences were observed between the levels of CRISPLD2 in surviving and non-surviving spesis patients. CRISPLD2 levels were negatively correlated with procalcitonin levels(r = −0.334, p<0.001).

Conclusions

The present study is the first to demonstrate the decreased expression of CRISPLD2 in septic shock and its association with PCT in sepsis. Further studies are needed to clarify the potential association between CRISPLD2 expression and clinical outcomes to determine if it could be used as a novel sepsis biomarker.

Chloroform extract of alfalfa (Medicago sativa) inhibits lipopolysaccharide-induced inflammation by downregulating ERK/NF-κB signaling and cytokine production

Alfalfa (Medicago sativa L.) is commonly used as a traditional medicine and functional food. This study investigated the anti-inflammatory potential of alfalfa and the mechanisms involved. The chloroform extract of alfalfa aerial parts inhibited lipopolysaccharide (LPS)-stimulated immune responses more than ether, butanol, or water soluble extracts. Treatment with 1 μg/mL LPS increased nitrite concentrations to 44.3 μM in RAW267.4 macrophages, but it was reduced to 10.6 μM by adding 100 μg/mL chloroform extract. LPS treatment also increased the concentrations of tumor necrosis factor-α, interleukin (IL)-6, and IL-1β to 41.3, 11.6, and 0.78 ng/mL in culture supernatants of the cells, but these cytokine levels decreased to 12.5, 3.1, and 0.19 ng/mL, respectively, by pretreating with 100 μg/mL of the extract. ICR mice injected with LPS (30 mg/kg body weight) alone showed a 0% survival rate after 48 h of the injection, but 48-h survival of the mice increased to 60% after oral administration of the extract. Subfractions of the chloroform extract markedly suppressed LPS-mediated activation of the extracellular signal-regulated kinase and nuclear factor kappa-B. Cinnamic acid derivatives and fatty acids were found to be active constituents of the extract. This research demonstrated that alfalfa aerial parts exert anti-inflammatory activity and may be useful as a functional food for the prevention of inflammatory disorders.

Humanized mice, a new model to study the influence of drug treatment on neonatal sepsis

Bacterial infection with group B Streptococcus (GBS) represents a prominent threat to neonates and fetuses in the Western world, causing severe organ damage and even death. To improve current therapeutic strategies and to investigate new approaches, an appropriate in vivo model to study the immune response of a human immune system is needed. Therefore, we introduced humanized mice as a new model for GBS-induced sepsis. Humanized mice feature deficiencies similar to those found in neonates, such as lower immunoglobulin levels and myeloid cell dysfunction. Due to the husbandry in specific-pathogen-free (SPF) facilities, the human immune cells in these mice also exhibit a naive phenotype which mimics the conditions in fetuses/neonates. Following infection, cytokine release and leukocyte trafficking from the bone marrow to the lymphoid organ (spleen) and into the peritoneum (site of infection) as well as bacterial spreading and clearance were traceable in the humanized mice. Furthermore, we investigated the effects of betamethasone and indomethacin treatment using this novel sepsis model. Although both drugs are commonly used in perinatal care, little is known about their effects on the neonatal immune system. Treatment of infected humanized mice not only induced the reduction of human leukocytes in the spleen but also increased the bacterial load in all analyzed organs, including the brain, which did not show infiltration of live GBS in untreated controls. These studies demonstrate the utility of the humanized mice as a new model to study an immature human immune response during bacterial infection and allow the investigation of side effects induced by various treatments.

Gene expression-based classifiers identify Staphylococcus aureus infection in mice and humans

Staphylococcus aureus causes a spectrum of human infection. Diagnostic delays and uncertainty lead to treatment delays and inappropriate antibiotic use. A growing literature suggests the host’s inflammatory response to the pathogen represents a potential tool to improve upon current diagnostics. The hypothesis of this study is that the host responds differently to S. aureus than to E. coli infection in a quantifiable way, providing a new diagnostic avenue. This study uses Bayesian sparse factor modeling and penalized binary regression to define peripheral blood gene-expression classifiers of murine and human S. aureus infection. The murine-derived classifier distinguished S. aureus infection from healthy controls and Escherichia coli-infected mice across a range of conditions (mouse and bacterial strain, time post infection) and was validated in outbred mice (AUC>0.97). A S. aureus classifier derived from a cohort of 94 human subjects distinguished S. aureus blood stream infection (BSI) from healthy subjects (AUC 0.99) and E. coli BSI (AUC 0.84). Murine and human responses to S. aureus infection share common biological pathways, allowing the murine model to classify S. aureus BSI in humans (AUC 0.84). Both murine and human S. aureus classifiers were validated in an independent human cohort (AUC 0.95 and 0.92, respectively). The approach described here lends insight into the conserved and disparate pathways utilized by mice and humans in response to these infections. Furthermore, this study advances our understanding of S. aureus infection; the host response to it; and identifies new diagnostic and therapeutic avenues.

Statins in the critically ill

The use or misuse of statins in critically ill patients recently attracted the attention of intensive care clinicians. Indeed, statins are probably the most common chronic treatment before critical illness and some recent experimental and clinical data demonstrated their beneficial effects during sepsis, acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), or after aneurismal subarachnoidal hemorrhage (aSAH). Due to the heterogeneity of current studies and the lack of well-designed prospective studies, definitive conclusions for systematic and large-scale utilization in intensive care units cannot be drawn from the published evidence. Furthermore, the extent of statins side effects in critically ill patients is still unknown. For the intensive care clinician, it is a matter of individually identifying the patient who can benefit from this therapy according to the current literature. The purpose of this review is to describe the mechanisms of actions of statins and to synthesize the clinical data that underline the relevant effects of statins in the particular setting of critical care, in an attempt to guide the clinician through his daily practice.

Diagnosis of adrenal failure in critically ill patients

In the last two decades there was important evolution on the knowledge of the function of the hypothalamic-pituitary-adrenal axis. In the last decade, the expression "relative adrenal insufficiency" (RAI) was created, and more recently "critical illness-related corticosteroid insufficiency" (CIRCI) was used to designate those patients in which cortisol production was not sufficiently increased in stress situations. Patients with CIRCI have elevated hospital morbidity and mortality. Currently, there is a wide discussion about diagnostic criteria for this dysfunction. Besides basal cortisol, some publications now study the role of other tests, such as cortrosyn test - either in low (1 μg) or high doses (250 μg); free cortisol, salivary cortisol, metyrapone test and others. With this review, we aimed at summarizing the results of the most influent papers that intended to define diagnostic criteria for CIRCI. We also suggest an approach for CIRCI diagnosis and make it clear that the decision about steroid therapy in septic shock patients is matter apart from RAI.

Low-dose hydrocortisone treatment for patients with septic shock: a pilot study comparing 3days with 7days

BACKGROUND AND OBJECTIVE

Although there is controversy regarding the benefit of low-dose corticosteroid therapy in patients with septic shock, the Surviving Sepsis Campaign has advocated that low-dose intravenous hydrocortisone be used to treat adult septic shock patients. This study investigated the effect of the duration of a stress dose of hydrocortisone on survival of septic shock patients with relative adrenal insufficiency.

METHODS

One hundred and thirty consecutive patients who met the American College of Chest Physicians/Society of Critical Care Medicine criteria for septic shock were included in the study. An additional inclusion criterion was vasopressor support after fluid resuscitation. The primary end-point was 28-day mortality, and the secondary end-points were shock reversal and mortality in the intensive care unit and hospital. All eligible patients were prospectively randomized to receive hydrocortisone treatment for 3 or 7days. Hydrocortisone treatment was started at a dose of 50mg every 6h.

RESULTS

Baseline data at recruitment did not differ between the two groups. After 28days, mortality did not differ between the 3- and 7-day treatment groups (33.8% vs 36.9%, P=0.629). Mortality rates in the intensive care unit and hospital did not differ significantly between the two groups. The median time to withdrawal of vasopressor therapy was 5.0days in the 3-day treatment group and 6.4days in the 7-day treatment group (P=0.102).

CONCLUSIONS

This pilot study showed that in patients with septic shock and relative adrenal insufficiency, 28-day mortality did not differ between those treated with low-dose hydrocortisone for 3 or 7days.

Carbachol alleviates rat cytokine release and organ dysfunction induced by lipopolysaccharide

BACKGROUND

To observe the influence of carbachol on inflammatory cytokine release and its protective role on organ function in rat endotoxemia model, and, furthermore, to investigate its receptor mechanism in rat peritoneal macrophages in vitro.

METHODS

In the animal experiments, Wistar rats were subjected to lipopolysaccharide (LPS) injection (5 mg/kg body weight) to establish an endotoxemia animal model, and carbachol/nicotine was given 15 minutes after LPS injection. Serum contents of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 were determined with enzyme-linked immunosorbent assay 4 hours after LPS injection. Plasma alanine aminotransferase, creatine kinase-MB, and diamine oxidase contents were detected 24 hours after LPS injection. In cell experiments, rat peritoneal macrophages were collected and initially pretreated with atropine (muscarinic cholinergic receptor antagonist) or α-Bungarotoxin (an antagonist that specifically binds α7 subunit of nicotinic cholinergic receptor), then with carbachol or nicotine, and finally stimulated with LPS. Contents of TNF-α, IL-6, and IL-10 in supernatant were assayed by enzyme-linked immunosorbent assay. Furthermore, macrophages were exposed to nicotine and carbachol of high concentration and then stained with fluorescein isothiocyanate-labeled α-bungarotoxin and observed with fluorescent confocal microscopy.

RESULTS

Carbachol inhibited expression of TNF-α and IL-6 after LPS injection and had no significant effect on IL-10 in rat endotoxemia model. It also inhibited the increase of plasma alanine aminotransferase and creatine kinase-MB contents whereas restored the inhibited plasma diamine oxidase activity. Cell experiments also showed that increases of TNF-α and IL-6 after LPS stimulation could be significantly inhibited by carbachol or nicotine, whereas IL-10 was not apparently altered. Atropine did not downregulate the inhibitive effects of both carbachol and nicotine, whereas α-bungarotoxin significantly downregulated these effects. Fluorescent confocal microscopy showed that nicotine and carbachol pretreatment markedly reduced the intensity of binding between fluorescein isothiocyanate-labeled α-bungarotoxin and macrophages.

CONCLUSION

The results suggested that both carbachol and nicotine play a role in the anti-inflammatory process and organ function protection through the α7 subunit of nicotinic cholinergic receptor.

[Reversing ICU-acquired immunosuppression: an innovative biomarker-guided therapeutic strategy for decreasing sepsis mortality and nosocomial infection rate]

Septic syndromes (systemic inflammatory response associated with infection) remain a major although largely under-recognized health care problem and represent the first cause of mortality in intensive care units. Regarding immune response, it is now agreed that sepsis induces an anti-inflammatory process, acting as a negative feedback. This inhibitory mechanism becomes deleterious as nearly all immune functions are rapidly compromised. The magnitude and persistence over time of this immunosuppression is correlated with nosocomial infections and mortality. Decreased HLA-DR expression on monocytes/increased percentage of regulatory T cells are biomarkers identifying patients at risk who could benefit from immunotherapy. This review attempts to integrate these new facts into an up-to-date account of sepsis pathophysiology.

Cecal ligation and puncture-induced impairment of innate immune function does not occur in the absence of caspase-1

Mice that have been subjected to cecal ligation and puncture (CLP) have an impaired ability to clear a subsequent Pseudomonas aeruginosa challenge compared with that of sham CLP controls. We hypothesized that this outcome is dependent upon a caspase-1 mechanism and tested this hypothesis by measuring caspase-1 after CLP and by measuring clearance of a bacterial challenge in caspase-1-deficient mice after CLP. Wild-type mice subjected to CLP had increased caspase-1 activity as well as increased IL-1β and increased IL-18 production in splenocytes stimulated with heat-killed Pseudomonas and had increased plasma concentrations of IL-1β and IL-18 and impaired clearance of a P. aeruginosa challenge compared with sham controls. Healthy, uninjured caspase-1(-\-) mice did not differ from wild-type mice in their ability to clear a Pseudomonas challenge. However, unlike wild-type mice, caspase-1(-/-) mice subjected to CLP had no impairment of bacterial clearance of the Pseudomonas challenge, suggesting that caspase-1 induction after CLP played a role in impairment of bacterial clearance. This was further substantiated by the use of a specific caspase-1 inhibitor, Ac-YVAD-CMK. Wild-type mice treated with Ac-YVAD-CMK (10 mg/kg s.c. twice daily, initiated at time of CLP) did not have impaired clearance of a Pseudomonas challenge compared with that of sham mice and had significantly improved bacterial clearance compared with that of untreated CLP mice. Increased caspase-1 expression and activity after CLP injury appears to contribute to diminished innate immune function.