Inflammatory cytokine response in patients with septic shock secondary to generalized peritonitis

Production of IFNβ by Conventional Dendritic Cells after Stimulation with Viral Compounds and IFNβ-Independent IFNAR1-Signaling Pathways are Associated with Aggravation of Polymicrobial Sepsis

Viral infections are associated with increased incidence of severe sepsis. Particularly during the early stages, type I interferons (IFNs) are known mediators of detrimental effects. However, the functional role of early interferon β (IFNβ) and its cellular source during sepsis in the context of preexisting viral infections has not been defined. Using the colon ascendens stent peritonitis (CASP) model, we demonstrate that IFNβ^−/− and type I IFN receptor (IFNAR1)^−/− mice were less susceptible to sepsis after pre-stimulation with the viral mimetic poly(I:C). Wild type (WT) mice treated with poly(I:C) exhibited altered expression patterns of TNF and IL-12p40 during CASP which were dependent on IFNβ or IFNAR1, suggesting a mechanism for the increased sepsis susceptibility of WT mice. Using a double cytokine reporter mouse model, we present novel data on the simultaneous expression of IFNβ and IL-12p40 on a single cell level during polymicrobial sepsis in vivo. Conventional dendritic cells (cDCs) were identified as primary source of IFNβ and the protective cytokine IL-12p40 after CASP surgery irrespective of poly(I:C) pre-stimulation. These data demonstrated that if polymicrobial sepsis is preceded by a viral infection, IFNβ and IL-12p40 are expressed by polyfunctional cDCs suggesting that these cells can play both detrimental and beneficial roles during sepsis development.

Pathophysiology of Acute Illness and Injury

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

Early mobilization for mechanically ventilated patients in the intensive care unit: a systematic review and meta-analysis

Background

Early mobilization (EM) is a regimen that was carried out by physiotherapists in a relatively early stage. It has been investigated by an increasing number of researchers. However, there has not been a meta-analysis concerning whether EM could benefit the clinical outcomes of critically ill patients requiring mechanical ventilation (MV). The present systematic review aims to evaluate the effect of EM compared with immobilization for mechanically ventilated patients.

Methods

A computerized literature search was performed in six databases for related articles from inception to June 2017. We included randomized controlled trials and controlled clinical trials and used the Physiotherapy Evidence Database scale to assess the quality of included studies. Primary outcomes were measures of muscle function, duration of MV, and incidence of mortality. Secondary outcomes were adverse effects and length of stay (LOS) in intensive care unit (ICU) and hospital.

Results

Eight trials were included; of those, only one study without standard EM reported that the intervention was invalid to improve the outcomes. The result of meta-analysis indicated that EM shortened the duration of MV; however, it had no positive effect on mortality and LOS in ICU.

Conclusions

This review suggests that EM improves the muscle function and ventilation duration. Further research highlighting standard intervention and specific groups is needed.

Severe persistent hypocholesterolemia after emergency gastrointestinal surgery predicts in-hospital mortality in critically ill patients with diffuse peritonitis

Background

Plasma cholesterol acts as a negative acute phase reactant. Total cholesterol decreases after surgery and in various pathological conditions, including trauma, sepsis, burns, and liver dysfunction. This study aimed to determine whether hypocholesterolemia after emergency gastrointestinal (GI) surgery is associated with in-hospital mortality in patients with diffuse peritonitis.

Methods

The medical records of 926 critically ill patients who had undergone emergency GI surgery for diffuse peritonitis, between January 2007 and December 2015, were retrospectively analyzed. The integrated areas under the curve (iAUCs) were calculated to compare the predictive accuracy of total cholesterol values from postoperative days (PODs) 0, 1, 3, and 7. Cox proportional hazard regression modeling was performed for all possible predictors identified in the univariate and multivariable analyses.

Results

The total cholesterol level measured on POD 7 had the highest iAUC (0.7292; 95% confidence interval, 0.6696–0.7891) and was significantly better at predicting in-hospital mortality than measurements on other days. The optimal total cholesterol cut-off value for predicting in-hospital mortality was 61 mg/dL and was determined on POD 7. A Cox proportional hazard regression analysis revealed that a POD 7 total cholesterol level < 61 mg/dL was an independent predictor of in-hospital mortality after emergency GI surgery (hazard ratio, 3.961; 95% confidence interval, 1.786–8.784).

Conclusion

Severe persistent hypocholesterolemia (<61 mg/dL) on POD 7 independently predicted in-hospital mortality, after emergency GI surgery, in critically ill patients with diffuse peritonitis.

Modulation by Polymyxin-B Hemoperfusion of Inflammatory Response Related to Severe Peritonitis

Conflicting results have been reported on the influence of Polymyxin-B hemoperfusion treatment on systemic inflammation markers. The aim of the study was to assess in a randomized control trial the influence on plasma cytokine concentrations of Polymyxin-B hemoperfusion in septic shock due to peritonitis. A panel of 10 pro- or anti-inflammatory cytokines was measured in 213 patients with peritonitis-induced septic shock enrolled in the randomized trial ABDOMIX testing the impact of 2 Polymyxin-B hemoperfusion sessions with standard treatment. Gram-negative bacteria were identified in 69% of patients. In the overall population, baseline plasma cytokine concentrations were not different between the two groups. Circulating tumor necrosis factor-α, interleukin (IL)-1β, IL-10, IL-6, and IL-1RA decreased significantly over time in both groups (P <0.0001 for all in controls, and P = 0.0002, 0.003, and <0.0001 in patients treated with Polymyxin-B hemoperfusion). IL-17A decreased significantly in patients treated with Polymyxin B hemoperfusion (P = 0.045) but not in controls. At the end of the second Polymyxin-B hemoperfusion session or at corresponding time in controls, plasma levels of cytokines did not differ between the two groups. Similar results were found in the subgroup of patients with gram-negative peritonitis who completed two Polymyxin-B hemoperfusion sessions. These results do not support a significant influence of Polymyxin-B hemoperfusion on circulating cytokines assessed except for IL-17A which clinical significance remains to be elucidated.

Intestinal permeability changes, systemic endotoxemia, inflammatory serum markers and sepsis after Whipple's operation for carcinoma of the pancreas head

POURPOSE

The aim was to evaluate the relationship between failure of gut barrier function, inflammatory markers and septic complications after pancreatoduodenectomy for pancreatic adenocarcinoma.

METHODOLOGY

44 patients were enrolled in this prospective observational clinical study and underwent curative open pancreatoduodenectomy for adenocarcinoma of the head of the pancreas. All patients underwent assessment of intestinal permeability using the lactulose/manitol excretions ratios (L/M ratio), endotoxemia, IL-1β, IL-6, CRP, and elastase levels before surgery and on postoperative days 1, 3 and 7. Septic complication was defined as a specific clinical condition related to infection by bacterium, virus, or fungus in a specific organ/compartment with positive culture.

RESULTS

Septic complications developed in 25% of patients. There were no significant differences in preoperative L/M ratio, endotoxine, CRP, IL-1β, IL-6, and elastase levels between sepsis-positive and sepsis-negative groups. All patients showed a significant increase in intestinal permeability, endotoxemia, IL-1, IL-6, CRP and elastase on the first postoperative day. At postoperative day 7, the sepsis-positive group continued to demonstrate an increase in intestinal permeability, endotoxemia and elastase; a significant difference was observed between the two groups (P = 0.02), whereas there was no significant difference in IL-1, IL-6, and CRP levels.

CONCLUSION

The pattern of change of intestinal permeability, systemic endotoxemia, and elastase concentration in the postoperative period is significantly higher in patients in whom sepsis develops, while the concentration of IL-1β, IL-6 and CRP do not permit to distinguish infection from inflammation.

Predictive value of C-reactive protein in critically ill patients after abdominal surgery

OBJECTIVES:

The development of sepsis after abdominal surgery is associated with high morbidity and mortality. Due to inflammation, it may be difficult to diagnose infection when it occurs, but measurement of C-reactive protein could facilitate this diagnosis. In the present study, we evaluated the predictive value and time course of C-reactive protein in relation to outcome in patients admitted to the intensive care unit (ICU) after abdominal surgery.

METHODS:

We included patients admitted to the ICU after abdominal surgery over a period of two years. The patients were divided into two groups according to their outcome: favorable (F; left the ICU alive, without modification of the antibiotic regimen) and unfavorable (D; death in the ICU, surgical revision with or without modification of the antibiotic regimen or just modification of the regimen). We then compared the highest C-reactive protein level on the first day of admission between the two groups.

RESULTS:

A total of 308 patients were included: 86 patients had an unfavorable outcome (group D) and 222 had a favorable outcome (group F). The groups were similar in terms of leukocytosis, neutrophilia, and platelet count. C-reactive protein was significantly higher at admission in group D and was the best predictor of an unfavorable outcome, with a sensitivity of 74% and a specificity of 72% for a threshold of 41 mg/L. No changes in C-reactive protein, as assessed based on the delta C-reactive protein, especially at days 4 and 5, were associated with a poor prognosis.

CONCLUSIONS:

A C-reactive protein cut-off of 41 mg/L during the first day of ICU admission after abdominal surgery was a predictor of an adverse outcome. However, no changes in the C-reactive protein concentration, especially by day 4 or 5, could identify patients at risk of death.

Inflammatory mediators in intra-abdominal sepsis or injury - a scoping review

Introduction

Inflammatory and protein mediators (cytokine, chemokine, acute phase proteins) play an important, but still not completely understood, role in the morbidity and mortality of intra-abdominal sepsis/injury. We therefore systematically reviewed preclinical and clinical studies of mediators in intra-abdominal sepsis/injury in order to evaluate their ability to: (1) function as diagnostic/prognostic biomarkers; (2) serve as therapeutic targets; and (3) illuminate the pathogenesis mechanisms of sepsis or injury-related organ dysfunction.

Methods

We searched MEDLINE, PubMed, EMBASE and the Cochrane Library. Two investigators independently reviewed all identified abstracts and selected articles for full-text review. We included original studies assessing mediators in intra-abdominal sepsis/injury.

Results

Among 2437 citations, we selected 182 studies in the scoping review, including 79 preclinical and 103 clinical studies. Serum procalcitonin and C-reactive protein appear to be useful to rule out infection or monitor therapy; however, the diagnostic and prognostic value of mediators for complications/outcomes of sepsis or injury remains to be established. Peritoneal mediator levels are substantially higher than systemic levels after intra-abdominal infection/trauma. Common limitations of current studies included small sample sizes and lack of uniformity in study design and outcome measures. To date, targeted therapies against mediators remain experimental.

Conclusions

Whereas preclinical data suggests mediators play a critical role in intra-abdominal sepsis or injury, there is no consensus on the clinical use of mediators in diagnosing or managing intra-abdominal sepsis or injury. Measurement of peritoneal mediators should be further investigated as a more sensitive determinant of intra-abdominal inflammatory response. High-quality clinical trials are needed to better understand the role of inflammatory mediators.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1093-4) contains supplementary material, which is available to authorized users.

Host response biomarkers in the diagnosis of sepsis: a general overview

Critically ill patients who display a systemic inflammatory response syndrome (SIRS) are prone to develop nosocomial infections. The challenge remains to distinguish as early as possible among SIRS patients those who are developing sepsis. Following a sterile insult, damage-associated molecular patterns (DAMPs) released by damaged tissues and necrotic cells initiate an inflammatory response close to that observed during sepsis. During sepsis, pathogen-associated molecular patterns (PAMPs) trigger the release of host mediators involved in innate immunity and inflammation through identical receptors as DAMPs. In both clinical settings, a compensatory anti-inflammatory response syndrome (CARS) is concomitantly initiated. The exacerbated production of pro- or anti-inflammatory mediators allows their detection in biological fluids and particularly within the bloodstream. Some of these mediators can be used as biomarkers to decipher among the patients those who developed sepsis, and eventually they can be used as prognosis markers. In addition to plasma biomarkers, the analysis of some surface markers on circulating leukocytes or the study of mRNA and miRNA can be helpful. While there is no magic marker, a combination of few biomarkers might offer a high accuracy for diagnosis.

Increased plasma levels of endozepines, endogenous ligands of benzodiazepine receptors, during systemic inflammation: a prospective observational study

Introduction

Recent work has shown that benzodiazepines interact with the immune system and exhibit anti-inflammatory effects. By using in vitro models, researchers in several studies have shown that the peptidergic endogenous ligands of benzodiazepine receptors, named endozepines, are involved in the immune response. All endozepines identified so far derive from diazepam-binding inhibitor (DBI), which generates several biologically active fragments. The aim of the present study was to measure plasma levels of DBI-like immunoreactivity (DBI-LI) in a rat model of sepsis and in patients with systemic inflammation from septic or non-septic origin.

Methods

Cecal ligation and puncture (CLP) or sham surgery was performed in rats. Blood samples were taken from animals, patients hospitalized for digestive surgery with inflammatory diseases, and healthy volunteers. Measurements of plasma DBI-related peptides were carried out by radioimmunoassay in animal and human samples.

Results

In the rats, CLP provoked an increase of plasma DBI-LI (+37%) 6 hours postsurgery. In humans, DBI-LI levels were significantly higher in the systemic inflammation group than in the healthy volunteer group (48.6 (32.7 to 77.7) pg/ml versus 11.1 (5.9 to 35.3) pg/ml, P < 0.001). We found a positive correlation between endozepine levels and Acute Physiology and Chronic Health Evaluation II score (r_s = 0.33 (0.026 to 0.58), P < 0.05) and tumor necrosis factor α levels (r_s = 0.43 (0.14 to 0.65), P < 0.01). The area under the receiver operating characteristic curve for endozepines was 0.842 (95% CI (0.717 to 0.966), P < 0.0001) for discriminating patients with inflammation from healthy volunteers.

Conclusions

Endozepines might be involved in the inflammatory response in patients with systemic inflammation.

Endocan, a putative endothelial cell marker, is elevated in preeclampsia, decreased in acute pyelonephritis, and unchanged in other obstetrical syndromes

Objective: Endocan, a dermatan sulphate proteoglycan produced by endothelial cells, is considered a biomarker for endothelial cell activation/dysfunction. Preeclampsia is characterized by systemic vascular inflammation, and endothelial cell activation/dysfunction. Therefore, the objectives of this study were to determine whether: (1) plasma endocan concentrations in preeclampsia differ from those in uncomplicated pregnancies; (2) changes in plasma endocan concentration relate to the severity of preeclampsia, and whether these changes are specific or observed in other obstetrical syndromes such as small-for-gestational age (SGA), fetal death (FD), preterm labor (PTL) or preterm prelabor rupture of membranes (PROM); (3) a correlation exists between plasma concentration of endocan and angiogenic (placental growth factor or PlGF)/anti-angiogenic factors (soluble vascular endothelial growth factor receptor or sVEGFR-1, and soluble endoglin or sEng) among pregnancies complicated by preeclampsia; and (4) plasma endocan concentrations in patients with preeclampsia and acute pyelonephritis (both conditions in which there is endothelial cell activation) differ.

Method: This cross-sectional study included the following groups: (1) uncomplicated pregnancy (n = 130); (2) preeclampsia (n = 102); (3) pregnant women without preeclampsia who delivered an SGA neonate (n = 51); (4) FD (n = 49); (5) acute pyelonephritis (AP; n = 35); (6) spontaneous PTL (n = 75); and (7) preterm PROM (n = 64). Plasma endocan concentrations were determined in all groups, and PIGF, sEng and VEGFR-1 plasma concentrations were measured by ELISA in the preeclampsia group.

Results: (1) Women with preeclampsia had a significantly higher median plasma endocan concentration than those with uncomplicated pregnancies (p = 0.004); (2) among women with preeclampsia, the median plasma endocan concentration did not differ significantly according to disease severity (p = 0.1), abnormal uterine artery Doppler velocimetry (p = 0.7) or whether diagnosis was made before or after 34 weeks gestational age (p = 0.3); (3) plasma endocan concentration in women with preeclampsia correlated positively with plasma anti-angiogenic factor concentrations [sVEGFR-1: Spearman rho 0.34, p = 0.001 and sEng: Spearman rho 0.30, p = 0.003]; (4) pregnancies complicated by acute pyelonephritis with bacteremia had a lower median plasma endocan concentration than pregnancies complicated by acute pyelonephritis without bacteremia (p = 0.004), as well as uncomplicated pregnancies (p = 0.001); and (5) there was no significant difference in the median plasma endocan concentration between uncomplicated pregnancies and those complicated by FD, delivery of an SGA neonate, PTL or preterm PROM (other members of the “great obstetrical syndromes”; each p > 0.05).

Conclusion: Median maternal plasma endocan concentrations were higher preeclampsia and lower in acute pyelonephritis with bacteremia than in uncomplicated pregnancy. No significant difference was observed in the median plasma endocan concentration between other great obstetrical syndromes and uncomplicated pregnancies. The difference in the direction of change of endocan in preeclampsia and acute pyelonephritis with bacteremia may be consistent with the view that both disease entities differ in pathogenic mechanisms, despite their associations with systemic vascular inflammation and endothelial cell activation/dysfunction.

Low perceived social support is associated with CD8+CD57+ lymphocyte expansion and increased TNF-α levels

Social support has been supposed to have a positive impact on the function of the immune system. However, the relationship between perceived social support and immune function has not yet been fully investigated. In this cross-sectional study, we investigated the link between perceived social support and lymphocyte subpopulations and cytokines. 232 healthy subjects provided a blood sample and completed the Multidimensional Scale of Perceived Social Support (MSPSS) questionnaire. Lymphocyte immunophenotypes and cytokines were determined. Significantly increased CD8+CD57+ lymphocytes and TNF-α levels were found in group with low perceived social support. Multivariate linear regression corrected for possible confounders confirmed a significant role of perceived social support in predicting the number of CD8+CD57+ lymphocyte and TNF-α levels. This study supports the association between perceived social support and immune function. In particular, poor social support may be related to a state of chronic inflammation sustained by CD8+CD57+ lymphocyte expansion and increased TNF-α levels.

Increased accumulation of CD16+ monocytes at local sites of inflammation in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) display a high prevalence of cardiovascular events and acute infections. Potential effector cells are the CD16(+) monocytes, known to be increased in the peripheral circulation in CKD. The aim of this study was to assess the expression of CD16 and CX3 CR1 on peripheral and in vivo extravasated monocytes in patients with CKD (GFR < 20 ml/min × 1.73 m²) using flow cytometry. In vivo extravasated monocytes were collected from a local inflammatory site, induced by a skin blistering technique. Soluble markers were assessed by Luminex. The number of CD16(+) monocytes was significantly higher in patients with CKD compared with healthy subjects, both in the peripheral circulation (P < 0.05) and at the site of induced inflammation (P < 0.001). Patients with CKD displayed significantly higher concentration of soluble CX3 CL1 both in the peripheral circulation (P < 0.01) and in the interstitial fluid (P < 0.001). In addition, patients with CKD had a significantly higher concentration of TNF-α in the peripheral circulation (P < 0.001). On the contrary, at the inflammatory site, concentrations of both TNF-α and IL-10 were significantly lower in patients with CKD compared with healthy controls (P < 0.05 for both). In conclusion, patients with CKD have an increased percentage of CD16(+) monocytes in both circulation and at the inflammatory site, and this finding is in concurrence with simultaneous changes in CX3 CR1. Together with distorted TNF-α and IL-10 levels, this may have potential impact on the altered inflammatory response in CKD.

Inhibition of IKKβ in enterocytes exacerbates sepsis-induced intestinal injury and worsens mortality

OBJECTIVES

Nuclear factor-κB is a critical regulator of cell-survival genes and the host inflammatory response. The purpose of this study was to investigate the role of enterocyte-specific NF-kB in sepsis through selective ablation of IkB kinase.

DESIGN

Prospective, randomized controlled study.

SETTING

Animal laboratories in university medical centers.

SUBJECTS AND INTERVENTIONS

Mice lacking functional NF-kB in their intestinal epithelium (Vil-Cre/Ikkβ) and wild-type mice were subjected to sham laparotomy or cecal ligation and puncture. Animals were killed at 24 hours or followed 7 days for survival.

MEASUREMENTS AND MAIN RESULTS

Septic wild-type mice had decreased villus length compared with sham mice, whereas villus atrophy was further exacerbated in septic Vil-Cre/Ikkβ mice. Sepsis induced an increase in intestinal epithelial apoptosis compared with sham mice, which was further exacerbated in Vil-Cre/Ikkβ mice. Sepsis induced intestinal hyperpermeability in wild-type mice compared with sham mice, which was further exacerbated in septic Vil-Cre/Ikkβ mice. This was associated with increased intestinal expression of claudin-2 in septic wild-type mice, which was further increased in septic Vil-Cre/Ikkβ mice. Both, pro-inflammatory and anti-inflammatory cytokines were increased in serum following cecal ligation and puncture, and interleukin 10 and monocyte chemoattractant protein-1 levels were higher in septic Vil-Cre/Ikkβ mice than in septic wild-type mice. All septic mice were bacteremic, but no differences in bacterial load were identified between wild-type and Vil-Cre/Ikkβ mice. To determine the functional significance of these results, animals were followed for survival. Septic wild-type mice had lower mortality than septic Vil-Cre/Ikkβ mice (47% vs 80%, p<0.05). Antitumor necrosis factor administration decreased intestinal apoptosis, permeability, and mortality in wild-type septic mice, and a similar improvement in intestinal integrity and survival were seen when antitumor necrosis factor was given to Vil-Cre/Ikkβ mice.

CONCLUSIONS

Enterocyte-specific NF-kB has a beneficial role in sepsis by partially preventing sepsis-induced increases in apoptosis and permeability, which are associated with worsening mortality.

Sepsis: multiple abnormalities, heterogeneous responses, and evolving understanding

Sepsis represents the host's systemic inflammatory response to a severe infection. It causes substantial human morbidity resulting in hundreds of thousands of deaths each year. Despite decades of intense research, the basic mechanisms still remain elusive. In either experimental animal models of sepsis or human patients, there are substantial physiological changes, many of which may result in subsequent organ injury. Variations in age, gender, and medical comorbidities including diabetes and renal failure create additional complexity that influence the outcomes in septic patients. Specific system-based alterations, such as the coagulopathy observed in sepsis, offer both potential insight and possible therapeutic targets. Intracellular stress induces changes in the endoplasmic reticulum yielding misfolded proteins that contribute to the underlying pathophysiological changes. With these multiple changes it is difficult to precisely classify an individual's response in sepsis as proinflammatory or immunosuppressed. This heterogeneity also may explain why most therapeutic interventions have not improved survival. Given the complexity of sepsis, biomarkers and mathematical models offer potential guidance once they have been carefully validated. This review discusses each of these important factors to provide a framework for understanding the complex and current challenges of managing the septic patient. Clinical trial failures and the therapeutic interventions that have proven successful are also discussed.

Local and systemic innate immune response to secondary human peritonitis

Introduction

Our aim was to describe inflammatory cytokines response in the peritoneum and plasma of patients with peritonitis. We also tested the hypothesis that scenarios associated with worse outcome would result in different cytokine release patterns. Therefore, we compared cytokine responses according to the occurrence of septic shock, mortality, type of peritonitis and peritoneal microbiology.

Methods

Peritoneal and plasma cytokines (interleukin (IL) 1, tumor necrosis factor α (TNFα), IL-6, IL-10, and interferon γ (IFNγ)) were measured in 66 patients with secondary peritonitis.

Results

The concentration ratio between peritoneal fluid and plasma cytokines varied from 5 (2 to 21) (IFNγ) to 1310 (145 to 3888) (IL-1). There was no correlation between plasma and peritoneal fluid concentration of any cytokine. In the plasma, TNFα, IL-6, IFNγ and IL-10 were higher in patients with shock versus no shock and in nonsurvivors versus survivors (P ≤0.03). There was no differential plasma release for any cytokine between community-acquired and postoperative peritonitis. The presence of anaerobes or Enterococcus species in peritoneal fluid was associated with higher plasma TNFα: 50 (37 to 106) versus 38 (29 to 66) and 45 (36 to 87) versus 39 (27 to 67) pg/ml, respectively (P = 0.02). In the peritoneal compartment, occurrence of shock did not result in any difference in peritoneal cytokines. Peritoneal IL-10 was higher in patients who survived (1505 (450 to 3130) versus 102 (9 to 710) pg/ml; P = 0.04). The presence of anaerobes and Enterococcus species was associated with higher peritoneal IFNγ: 2 (1 to 6) versus 10 (5 to 28) and 7 (2 to 39) versus 2 (1 to 6), P = 0.01 and 0.05, respectively).

Conclusions

Peritonitis triggers an acute systemic and peritoneal innate immune response with a simultaneous release of pro and anti-inflammatory cytokines. Higher levels of all cytokines were observed in the plasma of patients with the most severe conditions (shock, non-survivors), but this difference was not reflected in their peritoneal fluid. There was always a large gradient in cytokine concentration between peritoneal and plasma compartments highlighting the importance of compartmentalization of innate immune response in peritonitis.

A review of the efficacy of neuromuscular electrical stimulation in critically ill patients

BACKGROUND

Muscle wasting in critical illness has been identified as a major clinical concern which can lead to persistent muscle weakness, impede recovery and limit physical function and quality of life in survivors. Neuromuscular electrical stimulation (NMES) has been suggested as an alternative to active exercise in critically ill patients.

OBJECTIVES

To evaluate the efficacy of NMES in critically ill patients by evaluating the research literature.

METHODS

Structured database searches of the Cochrane Library, Ovid (Medline), CINHAL, Scopus and PEDro were completed.

RESULTS

Eight papers were retrieved and methodological quality evaluated using the Critical Appraisal and Skills Program tool. The NMES protocols, outcomes and findings were analysed and, given the methodological heterogeneity, the study findings were synthesised as a narrative. Analysis showed minimal adverse effects in the use of NMES and some potential benefits of NMES on preservation of muscle strength, decreased duration of mechanical ventilation and shorter Intensive Care Unit (ICU) length of stay.

CONCLUSIONS

Evidence of the clinical benefits of NMES in the ICU is inconclusive and provides minimal guidance for use in clinical practice. There is a need for further research in this area.

Effect of lipopolysaccharide, cytokines, and catecholamines on brain natriuretic peptide release from human myocardium

BACKGROUND

During sepsis and septic shock, elevated plasma concentrations of brain natriuretic peptide (BNP) have been reported but may be related to several underlying mechanisms. The aim of the present experimental study was to investigate the effect of lipopolysaccharide (LPS), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6), dobutamine (Dobu), epinephrine (Epi), and norepinephrine (Nor) on BNP synthesis by atrial human myocardium in vitro.

METHODS

After the approval of local ethics committee, right atrial appendages were obtained during cannulation for cardiac surgery and pinned in a isolated organ bath containing 15 ml of Tyrode's modified solution. Preparations were oxygenated, maintained at 36 ± 0.5°C and stimulated at a frequency of 1 Hz. A 60-min equilibration period was followed by 180-min exposure to 1 μM endothelin 1 (ET-1; n = 9), 20,000 pg/ml TNF-α (n = 10), 1000 pg/ml IL-1β (n = 10), 5000 pg/ml IL-6 (n = 10), 10,000 pg/ml LPS (n = 10), 100 μM Epi (n = 9), 100 μM Nor (n = 10), and 100 μM Dobu (n = 8). No product was added in Control group (n = 10). Two BNP dosages were performed: the first after 60 min of stabilization and the second after 180 min of stimulation. Absolute and relative changes in BNP concentration were compared between groups.

RESULTS

Exposure to ET-1 significantly increased BNP release as compared with Control group. Dobu, Epi, Nor, and LPS significantly increased BNP concentration but not TNF-α, IL-1β, or IL-6.

CONCLUSIONS

In vitro, LPS, Dobu, Epi, and Nor induced BNP synthesis by human atrial myocardium.

Vasopressors and inotropes in the treatment of human septic shock: effect on innate immunity?

Catecholamines have been suggested to modulate innate immune responses in experimental settings. The significance hereof in the treatment of human septic shock is unknown. We therefore sought if and how vasopressor/inotropic doses relate to pro-inflammatory mediators during treatment of septic shock. We prospectively studied 20 consecutive septic shock patients. For 3 days after admission, hemodynamic variables, lactate and plasma levels of interleukins (IL)-6 and 8, tumor necrosis factor (TNF)-α, and elastase-α₁-antitrypsin were measured six hourly. Doses of vasoactive drugs were recorded. Of the 20 patients, nine died in the intensive care unit. Dobutamine doses were positively associated and related to TNF-α plasma levels, independently of disease severity, hemodynamics, and outcome, in multivariable models. Dopamine doses were positively associated with IL-6, and norepinephrine was inversely associated with IL-8 and TNF-α levels. Our observations suggest that catecholamines used in the treatment of human septic shock differ in their potential modulation of the innate immune response to sepsis in vivo. Dobutamine treatment may contribute to circulating TNF-α and dopamine to IL-6, independently of activated neutrophils. Conversely, norepinephrine may lack pro-inflammatory actions.

Understanding the significance, reasons and patterns of abnormal vital signs after gastric bypass for morbid obesity

Anastomotic leaks and bleeding are the two most feared major complications in patients undergoing laparoscopic gastric bypass (LRYGB). This study was designed to evaluate if there is a clinical correlation between abnormal vital signs and postoperative leaks and bleeding. After IRB approval and adherence to HIPAA guidelines, a retrospective review of medical records was performed on 518 patients who underwent LRYGB between October 2002 and October 2006. Vital signs from each patient were monitored hourly. Eight patients out of 518 (1.54%) were discovered to have anastomotic leak. A marked increase in heart rate up to 120 bpm at 20 h after surgery occurred in five of eight patients (62.5%). Of the eight patients who had a leak, seven (87.5%) experienced sustained tachycardia above 120 bpm. On the other hand, 20 patients out of 518 (3.86%) were discovered to have postoperative bleeding. A gradual rather than a dramatic increase in heart rate was recorded in 17 of 20 patients (85%) starting 8 h after surgery. Five patients (25%) had unsustained tachycardia above 120 bpm. Twelve patients in this group (60%) were seen to have cyclical tachycardia that never exceeded 120 bpm at any point during hospitalization. Marginal hypotension was found in seven patients (35%) in this group. Sustained tachycardia with a heart rate exceeding 120 bpm appears to be an indicator of anastomotic leak. Tachycardia less than 120 bpm that has occurred in a cyclical pattern strongly pointed toward postoperative bleeding. Anastomotic leaks and bleeding are the two most feared major complications in patients undergoing LRYGB. This study was designed to evaluate if there is a clinical correlation between abnormal vital signs and postoperative leaks and bleeding.

The evolving experience with therapeutic TNF inhibition in sepsis: considering the potential influence of risk of death

INTRODUCTION

Septic shock is highly lethal and its incidence is increasing. Although TNF-α plays a key role in sepsis pathogenesis, past efforts to therapeutically inhibit it had limited success. However, there is continued interest in such therapies and there are now ongoing Phase II sepsis trials testing the effects of AZD9773, a TNF-directed polyclonal antibody fragment preparation. Experience with anti-inflammatory agents suggested that their efficacy may relate to sepsis-associated risk of death.

AREAS COVERED

An overview of the biology of TNF and experimental data implicating TNF as a key mediator in sepsis pathogenesis; a review of the earlier clinical experience with anti-TNF therapies demonstrating that when examined across 12 trials, these agents had a highly consistent overall effect which although not reaching significance, was on the side of benefit; a review of data showing that sepsis-associated risk of death may influence the efficacy of anti-inflammatory agents like anti-TNF ones and a review of the rational and clinical experience to date with AZD9773 and its precursor, CytoFab.

EXPERT OPINION

Discusses variables that may need to be accounted for to maximize the success of clinical trials in sepsis testing agents that modulate host inflammation.

Reactive oxygen species and p38 mitogen-activated protein kinase mediate tumor necrosis factor α-converting enzyme (TACE/ADAM-17) activation in primary human monocytes

Tumor necrosis factor α-converting enzyme (TACE) is responsible for the shedding of cell surface TNF. Studies suggest that reactive oxygen species (ROS) mediate up-regulation of TACE activity by direct oxidization or modification of the protein. However, these investigations have been largely based upon nonphysiological stimulation of promonocytic cell lines which may respond and process TACE differently from primary cells. Furthermore, investigators have relied upon TACE substrate shedding as a surrogate for activity quantification. We addressed these concerns, employing a direct, cell-based fluorometric assay to investigate the regulation of TACE catalytic activity on freshly isolated primary human monocytes during LPS stimulation. We hypothesized that ROS mediate up-regulation of TACE activity indirectly, by activation of intracellular signaling pathways. LPS up-regulated TACE activity rapidly (within 30 min) without changing cell surface TACE expression. Scavenging of ROS or inhibiting their production by flavoprotein oxidoreductases significantly attenuated LPS-induced TACE activity up-regulation. Exogenous ROS (H(2)O(2)) also up-regulated TACE activity with similar kinetics and magnitude as LPS. H(2)O(2)- and LPS-induced TACE activity up-regulation were effectively abolished by a variety of selective p38 MAPK inhibitors. Activation of p38 was redox-sensitive as H(2)O(2) caused p38 phosphorylation, and ROS scavenging significantly reduced LPS-induced phospho-p38 expression. Inhibition of the p38 substrate, MAPK-activated protein kinase 2, completely attenuated TACE activity up-regulation, whereas inhibition of ERK had little effect. Lastly, inhibition of cell surface oxidoreductases prevented TACE activity up-regulation distal to p38 activation. In conclusion, our data indicate that in primary human monocytes, ROS mediate LPS-induced up-regulation of TACE activity indirectly through activation of the p38 signaling pathway.

Procalcitonin in acute cardiac patients

Procalcitonin (PCT) levels are below the detection level in healthy subjects, while pre-procalcitonin mRNA is over expressed in human medullar thyroid carcinoma, in small cell lung tumor, and occasionally in other rare neuroendocrine tumors such as phaeochromocytoma. PCT is known as a sensitive and specific biomarker for bacterial sepsis, being produced by extra-thyroidal parenchymal tissues, mainly hepatocytes. The increase in plasma level correlates with the severity of infection and the magnitude and the time course of its increase can be strictly related to the patient's outcome, and to the bacterial load. So far, data on serum PCT levels in patients with cardiogenic shock and in those with acute coronary syndromes (ACS) are scarce and controversial. While some studies report that PCT levels are increased in ACS patients on admission, other investigations document that plasma PCT concentrations are in the normal range. We recently reported that the degree of myocardial ischemia (clinically indicated by the whole spectrum of ACS, from unstable angina to cardiogenic shock following ST-elevation myocardial infarction) and the related inflammatory-induced response are better reflected by C-reactive protein (which was positive in most acute cardiac care patients of all our subgroups) than by PCT, which seems more sensitive to a higher degree of inflammatory activation, being positive only in patients with cardiogenic shock. Few studies investigated the dynamics of PCT in cardiac acute patients, and, despite the paucity of data and differences in patients' selection criteria, an increase in PCT values seems to be associated with the development of complications. In acute cardiac patients, the clinical values of procalcitonin rely not on its absolute value, but only on its kinetics over time.

Effect of transcutaneous electrical muscle stimulation on muscle volume in patients with septic shock

OBJECTIVE

Intensive care unit admission is associated with muscle wasting and impaired physical function. We investigated the effect of early transcutaneous electrical muscle stimulation on quadriceps muscle volume in patients with septic shock.

DESIGN

Randomized interventional study using a single-legged exercise design with the contralateral leg serving as a paired control.

SETTING

A mixed 18-bed intensive care unit at a tertiary care university hospital.

PATIENTS

Eight adult male intensive care unit patients with septic shock included within 72 hrs of diagnosis.

INTERVENTIONS

After randomization of the quadriceps muscles, transcutaneous electrical muscle stimulation was applied on the intervention side for 7 consecutive days and for 60 mins per day. All patients underwent computed tomographic scans of both thighs immediately before and after the 7-day treatment period. The quadriceps muscle was manually delineated on the computed tomography slices, and muscle volumes were calculated after three-dimensional reconstruction.

MEASUREMENTS AND MAIN RESULTS

Median age and Acute Physiology and Chronic Health Evaluation II score were 67 years (interquartile range, 64-72 years) and 25 (interquartile range, 20-29), respectively. During the 7-day study period, the volume of the quadriceps muscle on the control thigh decreased by 16% (4-21%, p=.03) corresponding to a rate of 2.3% per day. The volume of the stimulated muscle decreased by 20% (3-25%, p=.04) corresponding to a rate of 2.9% per day (p=.12 for the difference in decrease). There was no difference in muscle volume between the stimulated and nonstimulated thigh at baseline (p=.10) or at day 7 (p=.12). The charge delivered to the muscle tissue per training session (0.82 [0.66-1.18] coulomb) correlated with the maximum sequential organ failure assessment score.

CONCLUSIONS

We observed a marked decrease in quadriceps volume within the first week of intensive care for septic shock. This loss of muscle mass was unaffected by transcutaneous electrical muscle stimulation applied for 60 mins per day for 7 days.

Temporal trends of circulating nitric oxide and pro-inflammatory cytokine responses ex vivo in intra-abdominal sepsis: results from a cohort study

OBJECTIVE AND DESIGN

To evaluate the association of pro-inflammatory mediators with organ dysfunction and adverse outcome in intra-abdominal sepsis patients.

SUBJECTS

Twenty-one patients admitted to the Intensive Care Unit (ICU) were prospectively included in the study. Only patients with surgical diagnosis of intra-abdominal sepsis were enrolled.

RESULTS

Tumor necrosis factor-α (TNFα) and interleukin (IL)-6 produced ex vivo were significantly lower in non-survivors on admission (p = 0.021) and day 2 (p = 0.013), respectively. Nitric oxide (NO(x)) levels were significantly higher in non-survivors from the onset of sepsis and until day 4 after diagnosis (p < 0.05). Circulating lymphocyte counts were lower in non-survivors after admission over time, but there was no association with impaired cytokine production in this group of patients during the entire follow-up. All non-survivors developed nosocomial pneumonia concomitantly with multiple organ dysfunction and septic shock. There was a significant correlation between nitric oxide (NO(x)) concentrations and the sequential organ failure assessment (SOFA) score at day 2 (r = 0.598, p = 0.009), and ICU stay (r = 0.605, p = 0.006). Continuously high NO(x) levels correlated with organ failure. The pro-inflammatory mediators TNFα, IL-6 and NO(x), and also the Simplified Acute Physiology Score II (SAPS-II), discriminate survivors from non-survivors. According to logistic regression models, although these parameters are independently associated with the outcome, they do not improve the predictive power of the SAPS-II score for mortality risk.

CONCLUSIONS

Disturbances in inflammatory responses and increase in NO(x) generation seem to characterize early intra-abdominal sepsis, in which immune suppression is associated with an increased susceptibility to nosocomial infections. Sequential NO(x) determinations could be a useful approach for improving the management of patients with intra-abdominal sepsis.

The hemodynamics of human septic shock relate to circulating innate immunity factors

The role of innate immunity, e.g., complement activation and cytokine release in the hemodynamic alterations in the course of human septic shock is largely unknown. We prospectively studied 14 consecutive septic shock patients with a pulmonary artery catheter in place. For 3 days after admission, hemodynamic variables and plasma levels of C3a, a product of complement activation, and interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α) were measured 6-hourly. Doses of vasoactive drugs were recorded. Of the 14 patients, 8 died in the ICU. Patients had a hyperdynamic circulation with tachycardia, mild hypotension, increased cardiac index, peripheral vasodilation and myocardial depression. C3a, IL-6 and TNF-α plasma levels were supranormal in 123 of 138 (89%), 132 of 138 (96%) and 83 of 111 (75%) measurements, respectively. Independently of blood culture results, treatment with vasoactive drugs and outcome, mean arterial blood pressure and systemic vascular resistance index were lower when IL-6 levels were higher and left ventricular function was less depressed when C3a levels were higher in the course of septic shock. The TNF-α levels did not invariably relate to peripheral vascular and myocardial function parameters. Our serial observations suggest that, in human septic shock, peripheral vasodilation is most strongly and independently, of all inflammatory factors, associated with IL-6 release, whereas complement activation partly offsets the myocardial depression of the syndrome. Innate immunity factors may thus differ in their contribution to the course of hemodynamic abnormalities of septic shock.

Prolonged inflammation following critical illness may impair long-term survival: a hypothesis with potential therapeutic implications

Despite successful intensive care a substantial portion of critically ill patients dies after discharge from the intensive care unit or hospital. Observational studies investigating long-term survival of critically ill patients reported that most deaths occur during the first months or year after discharge. Only limited data on the causes of impaired quality of life and post-intensive care unit deaths exist in the current literature. In this manuscript we hypothesize that the acute inflammatory response which characteristically accompanies critical illness is ensued by a prolonged imbalance or activation of the immune system. Such a chronic low-grade inflammatory response to critical illness may be sub-clinical and persist for a variable period of time after discharge from the intensive care unit and hospital. Chronic inflammation is a well-recognized risk factor for long-term morbidity and mortality, particularly from cardiovascular causes, and may thus partly contribute to the impaired quality of life as well as increased morbidity and mortality following intensive care unit and hospital discharge of critically ill patients. Assuming that critical illness is indeed followed by a prolonged inflammatory response, important implications for treatment would arise. An interesting and potentially beneficial therapy could be the administration of immune-modulating drugs during the time after intensive care unit or hospital discharge until chronic inflammation has subsided. Statins are well-investigated and effective drugs to attenuate chronic inflammation and could potentially also improve long-term outcome of critically ill patients after intensive care unit or hospital discharge. Future studies evaluating the course of inflammation during and after critical illness as well as its response to statin therapy are required.

IL-6 predicts organ dysfunction and mortality in patients with multiple injuries

Background

Although therapeutic concepts of patients with major trauma have improved during recent years, organ dysfunction still remains a frequent complication during clinical course in intensive care units. It has previously been shown that cytokines are upregulated under stress conditions such as trauma or sepsis. However, it is still debatable if cytokines are adequate parameters to describe the current state of trauma patients. To elucidate the relevance of cytokines, we investigated if cytokines predict development of multiple organ dysfunction syndrome (MODS) or outcome.

Methods

A total of 143 patients with an injury severity score ≥ 16, between 16 and 65 years, admitted to the Hannover Medical School Level 1 Trauma Center between January 1997 and December 2001 were prospectively included in this study. Marshall Score for MODS was calculated for at least 14 days and plasma levels of TNF-α, IL-1β, IL-6, IL-8 and IL-10 were measured. To determine the association between cytokine levels and development of MODS the Spearman rank correlation coefficient was calculated and logistic regression and analysis were performed.

Results and Discussion

Patients with MODS had increased plasma levels of IL-6, IL-8 and IL-10. IL-6 predicted development of MODS with an overall accuracy of 84.7% (specificity: 98.3%, sensitivity: 16.7%). The threshold value for development of MODS was 761.7 pg/ml and 2176.0 pg/ml for mortality during the in patient time.

Conclusion

We conclude that plasma IL-6 levels predict mortality and that they are a useful tool to identify patients who are at risk for development of MODS.

Factors associated with septic shock and mortality in generalized peritonitis: comparison between community-acquired and postoperative peritonitis

Introduction

The risk factors associated with poor outcome in generalized peritonitis are still debated. Our aim was to analyze clinical and bacteriological factors associated with the occurrence of shock and mortality in patients with secondary generalized peritonitis.

Methods

This was a prospective observational study involving 180 consecutive patients with secondary generalized peritonitis (community-acquired and postoperative) at a single center. We recorded peri-operative occurrence of septic shock and 30-day survival rate and analyzed their associations with patients characteristics (age, gender, SAPS II, liver cirrhosis, cancer, origin of peritonitis), and microbiological/mycological data (peritoneal fluid, blood cultures).

Results

Frequency of septic shock was 41% and overall mortality rate was 19% in our cohort. Patients with septic shock had a mortality rate of 35%, versus 8% for patients without shock. Septic shock occurrence and mortality rate were not different between community-acquired and postoperative peritonitis. Age over 65, two or more microorganisms, or anaerobes in peritoneal fluid culture were independent risk factors of shock. In the subgroup of peritonitis with septic shock, biliary origin was independently associated with increased mortality. In addition, intraperitoneal yeasts and Enterococci were associated with septic shock in community-acquired peritonitis. Yeasts in the peritoneal fluid of postoperative peritonitis were also an independent risk factor of death in patients with septic shock.

Conclusions

Unlike previous studies, we observed no difference in incidence of shock and prognosis between community-acquired and postoperative peritonitis. Our findings support the deleterious role of Enterococcus species and yeasts in peritoneal fluid, reinforcing the need for prospective trials evaluating systematic treatment against these microorganisms in patients with secondary peritonitis.

Procalcitonin kinetics within the first days of sepsis: relationship with the appropriateness of antibiotic therapy and the outcome

Introduction

Management of the early stage of sepsis is a critical issue. As part of it, infection control including appropriate antibiotic therapy administration should be prompt. However, microbiological findings, if any, are generally obtained late during the course of the disease. The potential interest of procalcitonin (PCT) as a way to assess the clinical efficacy of the empirical antibiotic therapy was addressed in the present study.

Methods

An observational cohort study including 180 patients with documented sepsis was conducted in our 15-bed medical intensive care unit (ICU). Procalcitonin measurement was obtained daily over a 4-day period following the onset of sepsis (day 1 (D1) to D4). The PCT time course was analyzed according to the appropriateness of the first-line empirical antibiotic therapy as well as according to the patient outcome.

Results

Appropriate first-line empirical antibiotic therapy (n = 135) was associated with a significantly greater decrease in PCT between D2 and D3 (ΔPCT D2–D3) (-3.9 (35.9) vs. +5.0 (29.7), respectively; P < 0.01). In addition, ΔPCT D2–D3 was found to be an independent predictor of first-line empirical antibiotic therapy appropriateness. In addition, a trend toward a greater rise in PCT between D1 and D2 was observed in patients with inappropriate antibiotics as compared with those with appropriate therapy (+5.2 (47.4) and +1.7 (35.0), respectively; P = 0.20). The D1 PCT level failed to predict outcome, but higher levels were measured in the nonsurvivors (n = 51) when compared with the survivors (n = 121) as early as D3 (40.8 (85.7) and 21.3 (41.0), respectively; P = 0.04). Moreover, PCT kinetics between D2 and D3 were also found to be significantly different, since a decrease ≥ 30% was expected in the survivors (log-rank test, P = 0.04), and was found to be an independent predictor of survival (odds ratio = 2.94; 95% confidence interval 1.22 to 7.09; P = 0.02).

Conclusions

In our study in an ICU, appropriateness of the empirical antibiotic therapy and the overall survival were associated with a greater decline in PCT between D2 and D3. Further studies are needed to assess the utility of the daily monitoring of PCT in addition to clinical evaluation during the early management of sepsis.

Inhibition of interleukin-6-transsignaling via gp130-Fc in hemorrhagic shock and sepsis

BACKGROUND

Immune function after hemorrhagic shock and subsequent sepsis is characterized by an early proinflammatory burst of IL-6, and high IL-6 levels have been linked to high mortality after trauma and in sepsis. Trans-signaling is defined as the activation of cells that do not express the membrane bound IL-6 receptor by the complex of IL-6 and the soluble IL-6 receptor (sIL-6R). Gp130-Fc is able to bind the IL-6/sIL-6R complex, and beneficial effects of IL-6 blockade in chronic inflammatory diseases have been shown. The first aim of this study was to investigate the potential effect of a gp130 blockade via the gp130-Fc antibody causing impairment of IL-6 signaling. The second aim was to find out what role the IL-6/sIL-6R complex can play in the context of hemorrhagic shock and subsequent sepsis as an acute inflammatory disease.

MATERIAL AND METHODS

Male CBA/J mice were subjected to hemorrhagic shock (35+/-5 mmHg for 90min and fluid resuscitation) or sham operation. At resuscitation each animal received either 0.5mg gp130-Fc or placebo (PL) i.p. At 48 h after resuscitation, both splenocytes and peritoneal macrophages (pMphi) were harvested or polymicrobial sepsis was induced by cecal ligation and puncture. Survival over 10 d was determined. Release of IL-6, TNF-alpha, and IL-10 of pMphi and release of IL-2, IL-10, and IFN-gamma of splenocytes was assessed by ELISA. Proliferation of splenocytes and their morphologic damage were determined.

RESULTS

Binding of the IL-6/sIL-6R complex by gp130-Fc led to significant lower IL-6 levels compared with placebo treated animals. Placebo treated males showed depressed proinflammatory immune response (IL-2, IL-6) after hemorrhagic shock. While splenocyte proliferation was significantly reduced directly after hemorrhagic shock and restored after 48 h by gp130-Fc, pMphi cytokine release was not influenced. Finally, survival appeared to be unaffected.

CONCLUSION

Transsignaling does not seem to play a pivotal role in the development of the immune dysfunction and mortality in our model of hemorrhage and subsequent sepsis.

Development of a lethal model of peritonitis for assessment of laparoscopic and laparotomic treatments in rats

PURPOSE

Development of a lethal model of peritonitis to assess the results of treating that peritonitis using videolaparoscopy and laparotomy.

METHODS

We developed a model of peritonitis in rats using cecal ligation (CLP) against a 2-mm diameter rigid mold and puncture. Two experiments were performed: determination of seven-day lethality; and analysis of white cell counts, blood cultures and cytokines (Interleukin-1 beta, Tumor Necrosis Factor-alpha and IL-6). The animals were divided into four groups: I--Sham surgery; II--CLP; III--CLP + Videolaparoscopy; and IV--CLP + Laparotomy .

RESULTS

Seven-day lethality was 0% in group I, 80% in the group II (p<0.05), 60% in group III , and 20 % in group IV. There was a significant reduction in leukocyte counts and higher levels of serum IL-1 beta, TNF-alpha and IL-6 in the group II compared to controls. The percentages of positive blood cultures were higher after videolaparoscopic compared to laparotomic treatment.

CONCLUSION

The experimental model provoked a lethal form of peritonitis and that videolaparoscopic treatment had more bacteraemia than laparotomy.

The innate immune response to secondary peritonitis

Secondary peritonitis continues to cause high morbidity and mortality despite improvements in medical and surgical therapy. This review combines data from published literature, focusing on molecular patterns of inflammation in pathophysiology and prognosis during peritonitis. Orchestration of the innate immune response is essential. To clear the microbial infection, activation and attraction of leukocytes are essential and beneficial, just like the expression of inflammatory cytokines. Exaggeration of these inflammatory systems leads to tissue damage and organ failure. Nonsurvivors have increased proinflammation, complement activation, coagulation, and chemotaxis. In these patients, anti-inflammatory systems are decreased in blood and lungs, whereas the abdominal compartment shows decreased neutrophil activation and decreased or stationary chemokine and cytokine levels. A later down-regulation of proinflammatory mediators with concomitant overexpression of anti-inflammatory mediators leads to immunoparalysis and failure to clear residual bacterial load, resulting in the occurrence of superimposed infections. Thus, in patients with adverse outcome, the inflammatory reaction is no longer contained within the abdomen, and the inflammatory response has shifted to other compartments. For the understanding of the host response to secondary peritonitis, it is essential to realize that the defense systems presumably are expressed differently and, in part, autonomously in different compartments.

Plasma interleukin-6 response is predictive for severity and mortality in canine systemic inflammatory response syndrome and sepsis

BACKGROUND

Sepsis is still a major cause of death in both human and veterinary medicine. Early diagnosis is essential for appropriate treatment. Identification of patients at risk for developing sepsis is already possible in human medicine through the measurement of plasma interleukin-6 (IL-6) levels. In veterinary medicine, however, this has been investigated only in canine experimental models.

OBJECTIVES

The purpose of this study was to measure IL-6 plasma levels in dogs with naturally occurring systemic inflammatory response syndrome (SIRS) and sepsis and to analyze the value of IL-6 as a predictive parameter for severity and mortality.

METHODS

Included in the study were 79 dogs that had been admitted to the small animal clinics of Munich and Berlin from July 2004 to July 2005 and that satisfied the diagnostic criteria for SIRS and sepsis as defined using established parameters. Measurement of plasma IL-6 levels on days 0, 1, and 2 was performed by the use of a colorimetric bioassay based on IL-6-dependent cell growth.

RESULTS

Septic foci were identified in 43 patients (septic group), and 36 patients were enrolled in the SIRS group. The frequency of positive blood cultures was 11%. The overall mortality rate was 48%. Higher plasma IL-6 levels on the day of admission were significantly correlated with a more severe degree of disease, increased mortality rate, and earlier fatality.

CONCLUSIONS

Plasma IL-6 concentration is predictive of outcome in canine SIRS and sepsis and may be a valuable laboratory parameter for assessing critically ill dogs.

Effects of anxiety on TNF-alpha levels during psychological stress

OBJECTIVES

Psychological stress can influence the immune system, which may result in stress-related illnesses. In this study, we investigated the effect of psychological stress and the coping skill on plasma cytokine levels.

MATERIALS AND METHODS

One hundred eighty-three students, at different stages of an academic year, participated in this study. Plasma tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-2 soluble receptor alpha, and IL-4 were measured and examined in relation to the measures of anxiety [State Anxiety Inventory (SAI)] and Bell Adjustment Inventory (BAI) score.

RESULTS

SAI scores were significantly higher in both midterm students (MTS) and examination-taking students (ETS), compared with the freshly admitted students (FAS). In addition, TNF-alpha levels were significantly different between the high- and the low-anxiety groups of ETS but not in MTS or FAS. The correlation between SAI scores and the BAI emotional scores was highest in the ETS group.

CONCLUSIONS

TNF-alpha level was significantly lower in the ETS group with high anxiety scores, and it is situation specific.

Cytokine-Release Patterns in Elderly Patients with Systemic Inflammatory Response Syndrome

BACKGROUND

Information is scarce about the inflammatory responses to infection in elderly patients.

OBJECTIVE

To investigate the inflammatory pattern in elderly patients with systemic inflammatory response syndrome (SIRS).

METHODS

We assessed the value of pro-inflammatory cytokines (TNF-alpha, IL-6, IL-1beta) and C-reactive protein (CRP) in elderly patients with SIRS at the time of consultation in the emergency room and on the fourth day of hospitalization.

RESULTS

Of 100 patients with SIRS, 92 had a clinical suspicion of infection and 46 were microbiologically confirmed. Basal TNF-alpha and IL-6 levels were higher in patients with bacteremia (p < 0.001 and p = 0.017, respectively). Basal levels of TNF-alpha (p < 0.001) and fourth-day levels of CRP (p = 0.004), TNF-alpha (p < 0.001) and IL-6 (p = 0.002) had a positive correlation with the length of hospitalization. Higher IL-6 levels on the fourth day showed a correlation with mortality (p = 0.016), while the other cytokines and CRP did not show this association.

CONCLUSION

Febrile elderly patients showed an inflammatory response pattern to infection equivalent to that reported in younger patients. Despite some limitations of our study, among febrile elderly patients, pro-inflammatory cytokine levels can be good markers for evaluating the prognosis of infections.

Organ dysfunction and long term outcome in secondary peritonitis

BACKGROUND AND AIMS

Secondary peritonitis is still associated with high mortality, especially when multiorgan dysfunction complicates the disease. Good prognostic tools to predict long term outcome in individual patients are lacking and therefore require further study.

PATIENTS AND METHODS

163 consecutive patients with secondary peritonitis were included, except those with postoperative or traumatic peritonitis. In 58 patients treated in the intensive care unit (ICU), organ dysfunction was quantified using Sequential Organ Failure Assessment (SOFA) score in the first 4 days. Predictive factors for poor outcome were evaluated in all patients. Hospital and 1-year mortality was assessed.

RESULTS

Hospital mortality was 19% and 1-year mortality 23%. Acute physiology and chronic health evaluation II (APACHE II), previous functional status, and sepsis category were predictive of fatal outcome in the total cohort (p = 0.034, p < 0.001, and p < 0.001). In patients treated in the ICU, advanced age and admission SOFA score were independent predictors of death (p = 0.014, p < 0.0001). The SOFA score showed the best discriminative ability for poor outcome (AuROC 0.78).

CONCLUSION

Degree of organ dysfunction measured using SOFA score was the best predictor of hospital mortality in patients suffering from secondary peritonitis.

Management of peritonitis in the critically ill patient

Severe secondary peritonitis carries significant mortality, despite advancements in critical care support and other therapies. Surgical management requires a multidisciplinary approach to guide the timing and the number of interventions necessary to eradicate the septic foci and create optimal healing with the fewest complications. Research is needed regarding the best surgical strategy for very severe cases. The use of deferred primary anastomosis seems safe in patients presenting with hemodynamic instability and hypoperfusion. These patients have a high risk of anastomotic failure and fistula formation. Allowing for aggressive resuscitation and judicious assessment of the progression of local inflammation are safe strategies to achieve the highest success and minimize serious and protracted complications in patients who survive the initial septic insult.

Surgical Therapy Attenuates Abdominal and Extra-Abdominal Inflammation in Experimental Peritonitis

BACKGROUND

This study examines the influence of surgical management (elimination of the infectious focus and abdominal lavage) on survival and the inflammatory response in the various compartments of the body: local (abdomen), systemic (blood) and distant organ (lungs).

MATERIALS AND METHODS

Peritonitis was established in mice by cecal ligation and puncture (CLP). After 24 h, a group was made in which the infected cecum was resected and the abdominal cavity was lavaged (RES), and another group that received no surgical resection (NoRES). Survival was examined over a period of 96 h. Mice were sacrificed at 24 (sham and CLP), 48 and 72 h after CLP to measure inflammatory parameters.

RESULTS

Survival was significantly lower is NoRES compared to sham and RES (p = 0.006, p = 0.014, respectively). Intraperitoneal parameters were improved in the RES group compared to sham but results were not significantly different between groups. In plasma, levels of interleukin-6 (IL-6) were decreased in RES (p = 0.048). Accordingly, anti-inflammatory IL-10 in plasma was increased in this group (p = 0.031). In the lung, keratinocyte-derived chemokine (KC) and myeloperoxidase (MPO) was reduced indicating decreased granulocytes accumulation in the lung in the RES group (p = 0.012 and p = 0.004, respectively).

CONCLUSIONS

In experimental secondary peritonitis surgical management improves survival and attenuates the inflammatory response predominantly in the extra-abdominal compartments. This illustrates the importance of surgery in prevention of multiple organ failure and denotes the compartmentalized character of the inflammatory response. This polymicrobial model with implicated surgical intervention reflects the clinical situation and may be more appropriate to test therapeutic interventions than a model involving only CLP.

Effect of melatonin on healing of colonic anastomosis in a rat model of peritonitis

BACKGROUND

The aim of this study is to determine the effect of melatonin on intestinal anastomosis in the presence of peritonitis.

MATERIAL AND METHODS

32 Wistar albino rats were randomized into four groups (n = 8): A (sham), B (control), C (melatonin 5 mg/kg), and D (melatonin 10 mg/kg). In group A, only cecal dissection was carried out. In the other groups, cecal ligation and puncture (CLP) followed cecal dissection in order to induce bacterial peritonitis. 24 h after the previous operation, cecal resection and ileocolic anastomosis were performed in the rats of all groups. In group C (5 mg/kg) and group D (10 mg/kg), melatonin was injected for 5 consecutive days starting after CLP. At the 48th hour of the CLP procedure, blood was drawn via the tail vein for tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) analysis, and on the 4th day of the experiment relaparotomy was carried out for bursting pressure (BP) measurements. The intestinal tissue containing the anastomotic line was then snap-frozen in liquid nitrogen and stored at -80 degrees C for determination of tissue levels of malondialdehyde (MDA) and glutathione (GSH).

RESULTS

The tissue MDA level, blood TNF-alpha and IL-6 levels of group B were significantly higher than in the other groups, whereas the BP results and GSH levels of group B were found to be significantly lower than in the other groups. The results of groups C and D are statistically different from those of group B. When we compared the results of groups C and D, we found significantly higher results in terms of BP and GSH levels in group D and also significantly lower results in terms of MDA, blood TNF-alpha and IL-6 levels in group D.

CONCLUSION

The findings of this experiment suggest that melatonin has a dose-independent positive effect on wound healing of colonic anastomosis.

[The importance of cytokines in the posttraumatic inflammatory reaction]

Alterations in the immune response after multiple trauma, posttraumatic sepsis and surgery are recognized as physiological reactions of the organism to restore homeostasis. The level of these immunological changes correlates with the degree of tissue damage as well as with the severity of haemorrhage and ischaemia. Cytokines are known to be integral components of this immune response. The local release of pro- and antiinflammatory cytokines after severe trauma indicates their potential to induce systemic immunological alterations. It appears that the balance or imbalance of these different cytokines partly controls the clinical course in these patients. Overproduction of either proinflammatory cytokines or antiinflammatory mediators may result in organ dysfunction. Whereas predominance of the proinflammatory response leads to the systemic inflammatory response syndrome (SIRS), the antiinflammatory reaction may result in immune suppression with an enhanced risk of infectious complications. Systemic inflammation, as well as immune suppression, are thought to play a decisive role in the development of multiple organ dysfunction syndrome (MODS). The major proinflammatory cytokines involved in the response to trauma and surgery include tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6 and IL-8. These cytokines, which are predominantly produced by monocytes and macrophages, mediate a variety of frequently overlapping effects, and their actions can be additive. TNF-alpha and IL-1beta are early regulators of the immune response and both induce the release of secondary cytokines, such as IL-6 and IL-8. IL-10 is an antiinflammatory cytokine which reduces the synthesis of proinflammatory mediators. Other important antiinflammatory mediators are soluble TNF receptors and the IL-1 receptor antagonist, which interfere with the effects of TNF-alpha and IL-1beta.Early evaluation of the prognosis of polytraumatized patients and assessment of their clinical status is known to be difficult. Therefore, in several clinical studies, cytokine levels during the posttraumatic course have been determined with the aim of finding predictive markers of patient outcome. The purpose of this review was to highlight our current knowledge on the interaction of posttraumatic immune reactivity and the development of complications. A better understanding of these mechanisms might lead to the introduction of preventive and therapeutic strategies into clinical practice.

Regulation of peritoneal and systemic neutrophil-derived tumor necrosis factor-alpha release in patients with severe peritonitis: role of tumor necrosis factor-alpha converting enzyme cleavage

OBJECTIVE

Polymorphonuclear neutrophil (PMN) influx and peritoneal tumor necrosis factor (TNF)-alpha production are key host defense mechanisms during peritonitis. The aim of this study was to explore the potential interactions between TNF-alpha production and TNF-alpha converting enzyme (TACE) expression by PMN in the blood and peritoneum of patients with severe peritonitis.

DESIGN

A prospective study.

SETTING

A surgical adult intensive care unit in a university hospital.

PATIENTS

A total of 29 consecutive immunocompetent patients with severe sepsis within 48 hrs of onset were enrolled and underwent laparotomy for a diffuse secondary peritonitis. Thirteen volunteers served as controls.

MEASUREMENTS

Blood and peritoneal fluid recovered during laparotomy were analyzed and compared for 1) soluble TNF-alpha, soluble L-selectin, and type I and II TNF-alpha receptor levels; 2) PMN membrane TNF-alpha, membrane L-selectin, and TACE expression (flow cytometry); and 3) TNF-alpha production by cultured PMN. Correlations between these forms of PMN-derived TNF-alpha and the severity of the peritonitis and patient's outcome were investigated.

MAIN RESULTS

Elevated soluble TNF-alpha levels in both plasma and peritoneal fluid from the patients were found, together with decreased expression of membrane TNF-alpha and TACE up-regulation at the PMN surface. Soluble L-selectin and type I and II TNF receptors were highly released, suggesting also the role of TACE. In contrast, the capacity of both blood and peritoneal PMN to synthesize TNF-alpha in vitro, in optimal conditions of stimulation (lipopolysaccharide + interferon-gamma), was impaired as compared with controls' blood PMN. Regulation of PMN-derived TNF-alpha was similar in the two compartments, but responses were more pronounced in the peritoneum. TACE up-regulation at the surface of blood-derived PMN correlated with the Sequential Organ Failure Assessment score and vital outcome.

CONCLUSION

These human data demonstrate that mTACE is up-regulated at the PMN surface during severe peritonitis. This finding could be related to a paracrine regulatory loop involving some TACE substrates such as TNF-alpha, L-selectin, and TNF receptors.

Persistent elevation of serum interleukin-6 in intraabdominal sepsis identifies those with prolonged length of stay

BACKGROUND/PURPOSE

Elevated serum interleukin-6 (IL-6) levels in patients with intraabdominal sepsis have been associated with increased morbidity and mortality. The authors hypothesized that after surgical intervention a persistent elevation of IL-6 would more accurately reflect the inflammatory state and thus predict the subsequent time to recovery better than the preoperative value alone.

METHODS

Nineteen consecutive children with peritonitis and manifestations of the systemic inflammatory response syndrome were enrolled prospectively. IL-6 levels were determined from pre- and postoperative serum samples (within 12 to 24 hours) by enzyme-linked immunosorbant assay (ELISA). Patient postoperative length of stay (LOS) was recorded.

RESULTS

Before surgery, patient serum IL-6 levels ranged from 48 to 132,546 pg/mL. LOS ranged from 4 to 60 days, with subjects falling into 2 groups of < or =11 (n = 14) and > or =25 (n = 5) days. Using an IL-6 level greater than 500 pg/mL to predict a prolonged LOS (>11 days), a persistent elevation of IL-6 postoperatively appears to increase the likelihood of a prolonged LOS.

CONCLUSIONS

Persistent IL-6 levels greater than 500 pg/mL may be useful in identifying pediatric intraabdominal sepsis patients with prolonged LOS and presumably greater morbidity. Rapid identification of these patients may allow for novel therapeutic interventions.

The Severity of Infection Induces a Shift in the Type 1/Type 2 T-Helper Cell Balance in Patients with or without Peritonitis

BACKGROUND

A type-1 to type-2 T-helper cell (Th1/Th2) shift is hypothesized to occur among patients with severe trauma and pancreatitis. It was hypothesized that the Th2 situation caused an immune-suppressed period that led to a critical imbalance in the patients' conditions, with an increased risk of multiple organ failure and mortality.

METHODS

In eight patients with localized intra-abdominal infection (diverticulitis) and six patients with peritonitis due to perforation of a hollow viscus, we examined the cytokine response of CD3(+) T cells in the greater omentum and in the peripheral blood by in vitro stimulation, intracellular cytokine staining, and flow cytometry for TNF-alpha, IFN-gamma, IL-2, and IL-4. Follow-up cytokine assays were carried out on peripheral blood on days 3 and 7. Different levels of cytokine expression in each group were examined to determine the origin of the lymphocytes, both from omentum or peripheral blood. Cytokine production in the diverticulitis group was compared with that of the peritonitis patients.

RESULTS

In localized infections (diverticulitis), there was higher expression of TNF-alpha (51%/35% positive cells in omentum/blood), IFN-gamma (47%/32%), and IL-2 (33%/20%) in the omentum than in the peripheral blood mononuclear cells (PMBCs), but this was not true for IL-4 expression (0.8%/1.3%). In patients with peritonitis, there were no differences in cytokine expression between lymphocytes from the greater omentum and from PMBCs for TNF-alpha (18%/21% omentum/blood), IFN-gamma (20%/22%), IL-2 (16%/12%), or IL-4 (10.9%/7.6%). Compared to the diverticulitis group, patients with peritonitis showed reduced expression for TNF-alpha, IFN-gamma, and IL-2, but there was a significantly higher response for IL-4 for both compartments.

CONCLUSIONS

There was a shift from Th1 to Th2 in patients with severe clinical symptoms of peritonitis. Immune suppression is evident because of the T cell response in the greater omentum, but immunosuppression seems to not reach its maximum level before day 7 post operation. This differs from findings in multiple trauma and pancreatitis; however, it is parallel to the clinical situation in patients with peritonitis.

Current concepts in peritonitis

Peritonitis is a serious and common infection. Its pathogenesis and microbiology have been well defined. Such risk factors as age, site of infection, physiologic response of the patient, presence of organ dysfunction, and malnutrition may influence the outcome of this disease process. The presence of antibiotic-resistant organisms and delays in operative intervention are also associated with treatment failure and higher mortality. Surgeons have the greatest impact on this disease in their ability to control the source of infection and to administer proper antimicrobial therapy.

Intensive care unit management of intra-abdominal infection

OBJECTIVE

To review the biologic characteristics of, and management approaches to, intra-abdominal infection in the critically ill patient.

DESIGN

Narrative review.

SETTING

Medline review focussed on intra-abdominal infection in the critically ill patient.

PATIENTS AND SUBJECTS

Restricted to studies involving human subjects.

INTERVENTIONS

None.

RESULTS

Intra-abdominal infections are an important cause of morbidity and mortality in the intensive care unit (ICU). Peritonitis can be classified as primary, secondary, or tertiary, the unique pathologic features reflecting the complex nature of the endogenous gut flora and the gut-associated immune system, and the alterations of these that occur in critical illness. Outcome is dependent on timely and accurate diagnosis, vigorous resuscitation and antibiotic support, and decisive implementation of optimal source control measures, specifically the drainage of abscesses and collections of infected fluid, the debridement of necrotic infected tissue, and the use of definitive measures to prevent further contamination and to restore anatomy and function.

CONCLUSIONS

Optimal management of intra-abdominal infection in the critically ill patient is based on the synthesis of evidence, an understanding of biologic principles, and clinical experience. An algorithm outlining a clinical approach to the ICU patient with complex intra-abdominal infection is presented.

Interleukin-18 concentration in the peritoneal fluid correlates with the severity of peritonitis

BACKGROUND

Interleukin (IL)-18 is a novel cytokine that has recently been characterized as an inducer of interferon-gamma (IFN-gamma). The aim of this study was to investigate the clinical significance of peritoneal IL-18 concentrations in patients with peritonitis.

METHODS

We measured IL-18, IFN-gamma, and IL-10 concentrations in the peritoneal fluid of 28 patients undergoing laparotomy for peritonitis. Correlations between the peritoneal cytokine concentrations and the severity of illness determined by systemic inflammatory response syndrome (SIRS) criteria, Acute Physiological and Chronic Health Evaluation II (APACHE II) score, peritoneal fluid bacterial culture results, subsequent development of organ failure, and length of hospital stay were assessed.

RESULTS

Interleukin-18 concentration was significantly increased in patients who developed SIRS, in those with culture-positive peritonitis, and in those who developed organ failure, as compared with the other patients. Interleukin-10 concentration, which was also significantly increased in patients with culture-positive peritonitis, showed a close correlation with IL-18 concentration. Although a weak correlation was observed between IL-18 and IFN-gamma concentrations, IFN-gamma concentrations did not show any association with patients' clinical parameters. However, the IFN-gamma/IL-18 ratio was significantly lower in patients with an APACHE II >/=10, and in those with culture-positive peritonitis, as compared with the other patients.

BACKGROUND

Peritoneal IL-18 concentration increased in response to intraperitoneal bacterial infection and seemed to reflect the severity of peritonitis. However, the capacity of IL-18 to produce IFN-gamma may be altered depending on the severity of peritonitis.