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

Post-Operative Increase in Serum Interleukin-6 Is Associated With Longer Hospital Stay in Children Operated on for Acute Appendicitis: A Pilot Study

Background: Pediatric acute appendicitis (PAA) involves a substantial consumption of health and economic resources. The identification of serum biomarkers that may help predict the post-surgical evolution of these patients is a field of great interest. Patients and Methods: This was a prospective, observational substudy within the Biomarkers for the Diagnosis of Appendicitis in Pediatrics (BIDIAP) cohort aimed at evaluating the association between post-surgical increase in serum IL-6 and different outcomes related to the clinical evolution of children operated on for PAA. Sixty-nine children with a confirmed diagnosis of acute appendicitis and both pre-operative and post-operative serum IL-6 were included in the study. Three multivariable-adjusted linear regression models were fitted to analyze the association between an increase of >10% in post-operative serum IL-6 level with the length of stay, the number of post-operative emetic episodes, and the onset of oral feeding. Two multivariable-adjusted logistic regression models were fitted to assess the association of the same exposure with the indication of antibiotherapy at discharge and with positivity in peritoneal fluid culture. Results: Thirteen children showed an increase of >10% in the post-operative serum IL-6 value (group 1) whereas 56 showed only a minor increase, or no change (group 2). After accounting for potential confounders, children in group 1 had a mean of three-day longer hospital stay (difference, 3.33; 95% confidence interval [CI], 0.57-6.09) and higher odds of a positive result in peritoneal fluid culture (odds ratio [OR], 37.43; 95% CI, 1.02-1361.28) than children in group 2. Conclusions: An increase of >10% in post-operative serum IL-6 value could predict longer hospital stay and higher odds of positive peritoneal fluid culture. Future prospective studies are needed to replicate these findings and to broaden the range of biomarkers that could predict the post-operative evolution of children operated on for PAA.

Cytokine clearance in serum and peritoneal fluid of patients undergoing damage control surgery with abdominal negative pressure therapy for abdominal sepsis

Objectives

Open abdomen technique with negative pressure therapy (NPT) is widely used in patients with severe abdominal sepsis. The aim of this study was to evaluate cytokine clearance in serum and peritoneal fluid during NPT.

Methods

This prospective pilot study included six patients with severe abdominal sepsis requiring discontinuity resection and NPT for 48 h followed by planned reoperation. Cytokines (IL6, IL8, IL10, TNFalpha, and IL1beta) were measured in the serum and peritoneal fluid during index operation, on postoperative days 0, 1, and 2.

Results

Concentrations of cytokines in peritoneal fluid were higher than in serum. IL10 showed a clearance both in serum (to 16.6%, p=0.019) and peritoneal fluid (to 40.9%, p=0.014). IL6 cleared only in serum (to 24.7%, p=0.001) with persistently high levels in peritoneal fluid. IL8 remained high in both serum and peritoneal fluid. TNFalpha and IL1beta were both low in serum with wide range of high peritoneal concentrations. Only TNFalpha in peritoneal fluid showed significant differences between patients with ischemia vs. perforation (p=0.006).

Conclusions

The present pilot study suggests that cytokines display distinct patterns of clearance or persistence in the peritoneal fluid and serum over the first 48 h of treatment in severe abdominal sepsis with NPT.

Changes in blood biomarkers in Arabian horses with Clostridium difficile-induced enterocolitis

Clostridium difficile (CD) is considered a major health care problem both in developing and developed countries; frequently reported to be associated with enterocolitis and diarrhea in horses and other animals. In this study, we examined acute phase response (APR), cytokines response, neopterin (NP) procalcitonin (PCT) production and oxidative stress condition in horses and foals with C. difficile-induced enterocolitis (CDIE) and evaluated the effectiveness of these parameters as biomarkers for the disease. A total of 407 Arabian horses in 35 stables were examined between January 2017 to December 2018. Only 24 out of 407 horses showed two or more signs of CDIE. The blood level of serum amyloid A (SAA), haptoglobin (HP), proinflammatory cytokines (TNF-α, IL-6 and IL1-β), serum malondialdehyde (MDA), PCT and NPT in horses with CDIE were higher than in healthy horses. Nevertheless, the levels of nitric oxide (NO), superoxide dismutase (SOD) and total antioxidant concentration (TAC) were considerably lower in diseased horses compared to those that were healthy. The ROC curves for eleven selected blood parameters, both in healthy horses and horses with CDIE demonstrated that all examined blood markers had significant levels of differentiation between CDIE cases and healthy controls (AUC > 87.5). The data in this study suggest that the evaluation of acute-phase proteins, cytokines, PCT, NPT, and oxidative stress biomarkers may well be used as a tool for diagnosis and assessment of CDIE and in disease pathogenesis in Arabian horses.

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.

Effects of sodium methyldithiocarbamate on selected parameters of innate immunity and clearance of bacteria in a mouse model of sepsis

AIMS

Sodium methyldithiocarbamate (SMD), the third most widely used conventional pesticide in the United States, has been reported to inhibit several parameters associated with inflammation and to decrease resistance to infection. In a previous study, survival time was markedly decreased when mice were treated orally with SMD shortly before challenge with a high dose of Escherichia coli (E. coli) that was lethal to most of the control mice. In the present study, we evaluated selected parameters of the innate immune system using a lower challenge dose of E. coli, to determine which (if any) of these parameters reflected continued changes through 24h.

MAIN METHODS

Bacterial clearance from the peritoneal cavity, production of chemokines and cytokines, and body temperature were measured.

KEY FINDINGS

All these parameters were reduced by SMD up to 12h after bacterial challenge, but the concentration of the anti-inflammatory cytokine IL-10 was increased. Even so, mice in the control and SMD-treated groups cleared most bacteria by 24h. Other parameters (cytokine concentrations and body temperature) were also normal or near normal by 24h. The same dosage of SMD administered intranasally also did not significantly decrease survival. Hypothermia from 16 to 28 h correlated with lethal outcome, but SMD significantly increased hypothermia only at 2 and 4h after challenge.

SIGNIFICANCE

In spite of substantial early inhibition by SMD of parameters known to be important for resistance to infection, bacterial clearance and survival were not altered, suggesting immunological reserve and/or rapid recovery after transient effects of SMD.

Protective effects of the combination of sodium ferulate and oxymatrine on cecal ligation and puncture-induced sepsis in mice

The aim of this study was to investigate the effects of the combination of sodium ferulate (SF) and oxymatrine (OMT) on mice with cecal ligation and puncture (CLP)-induced sepsis. Swiss male mice were randomly divided into a control group, CLP group, three SF + OMT groups (3.1+6.9; 6.2+13.8 and 12.3+27.7 mg/kg), SF (6.2 mg/kg) group and OMT (13.8 mg/kg) group. Eight hours after the administration of the drugs, the survival rates and survival times of the animals were monitored. In addition, the lung wet/dry weight (W/D) ratio; alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in the serum; the C-reactive protein (CRP), interleukin-6 (IL-6) and interferon-γ (IFN-γ) levels in the serum and lung and liver homogenates; and the malondialdehyde (MDA) and superoxidase dismutase (SOD) levels in the lung and liver homogenates were measured. The bacterial load in the serum was also studied. Following treatment with the combination of SF and OMT, the survival rate increased and the survival time was prolonged; CLP-induced increases in the lung W/D ratio and the levels of ALT, AST, LDH, CRP, IL-6, IFN-γ and MDA were significantly reduced; and the SOD activity levels were increased, compared with those of the untreated animals with CLP-induced sepsis. These results indicated that the combination of SF and OMT induced protective effects against CLP-induced lethal sepsis of mice. The possible mechanism of these effects may be associated with the alleviation of systemic inflammation and diminishment of oxidative injury.

Splenic stromal cells from aged mice produce higher levels of IL-6 compared to young mice

Inflamm-aging indicates the chronic inflammatory state resulting from increased secretion of proinflammatory cytokines and mediators such as IL-6 in the elderly. Our principle objective was to identify cell types that were affected with aging concerning IL-6 secretion in the murine model. We compared IL-6 production in spleen cells from both young and aged mice and isolated several types of cells from spleen and investigated IL-6 mRNA expression and protein production. IL-6 protein productions in cultured stromal cells from aged mice spleen were significantly high compared to young mice upon LPS stimulation. IL-6 mRNA expression level of freshly isolated stromal cells from aged mice was high compared to young mice. Furthermore, stromal cells of aged mice highly expressed IL-6 mRNA after LPS injection in vivo. These results suggest that stromal cells play a role in producing IL-6 in aged mice and imply that they contribute to the chronic inflammatory condition in the elderly.

Efficacy and safety of active negative pressure peritoneal therapy for reducing the systemic inflammatory response after damage control laparotomy (the Intra-peritoneal Vacuum Trial): study protocol for a randomized controlled trial

Background

Damage control laparotomy, or abbreviated initial laparotomy followed by temporary abdominal closure (TAC), intensive care unit resuscitation, and planned re-laparotomy, is frequently used to manage intra-abdominal bleeding and contamination among critically ill or injured adults. Animal data suggest that TAC techniques that employ negative pressure to the peritoneal cavity may reduce the systemic inflammatory response and associated organ injury. The primary objective of this study is to determine if use of a TAC dressing that affords active negative pressure peritoneal therapy, the ABThera Open Abdomen Negative Pressure Therapy System, reduces the extent of the systemic inflammatory response after damage control laparotomy for intra-abdominal sepsis or injury as compared to a commonly used TAC method that provides potentially less efficient peritoneal negative pressure, the Barker’s vacuum pack.

Methods/Design

The Intra-peritoneal Vacuum Trial will be a single-center, randomized controlled trial. Adults will be intraoperatively allocated to TAC with either the ABThera or Barker’s vacuum pack after the decision has been made by the attending surgeon to perform a damage control laparotomy. The study will use variable block size randomization. On study days 1, 2, 3, 7, and 28, blood will be collected. Whenever possible, peritoneal fluid will also be collected at these time points from the patient’s abdomen or TAC device. Luminex technology will be used to quantify the concentrations of 65 mediators relevant to the inflammatory response in peritoneal fluid and plasma. The primary endpoint is the difference in the plasma concentration of the pro-inflammatory cytokine IL-6 at 24 and 48 h after TAC dressing application. Secondary endpoints include the differential effects of these dressings on the systemic concentration of other pro-inflammatory cytokines, collective peritoneal and systemic inflammatory mediator profiles, postoperative fluid balance, intra-abdominal pressure, and several patient-important outcomes, including organ dysfunction measures and mortality.

Discussion

Results from this study will improve understanding of the effect of active negative pressure peritoneal therapy after damage control laparotomy on the inflammatory response. It will also gather necessary pilot information needed to inform design of a multicenter trial comparing clinical outcomes among patients randomized to TAC with the ABThera versus Barker’s vacuum pack.

Trial registration

ClinicalTrials.gov identifier http://www.clicaltrials.gov/ct2/show/NCT01355094

Association of adrenocorticotrophin and cortisol concentrations with peripheral blood leukocyte cytokine gene expression in septic and nonseptic neonatal foals

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) is influenced by the proinflammatory cytokines IL-6, IL-1β, and TNF-α in critically ill humans. Information about the association of cytokines with the HPA axis in neonatal foals is lacking.

HYPOTHESIS/OBJECTIVES

The objectives were to describe for hospitalized septic and nonseptic foals (1) temporal changes in blood concentrations of ACTH, and cortisol, and leukocyte cytokine gene expression, and (2) coassociation of these HPA axis hormones with blood leukocyte cytokine gene expression.

ANIMALS

Hospitalized septic foals (N = 15) and hospitalized nonseptic foals (N = 11).

METHODS

Blood samples, obtained from study foals at admission (T = 0), and 24 (T = 1), 48 (T = 2), 72 (T = 3), and 96 (T = 4) hours after admission, were processed to isolate RNA from leukocytes and to harvest plasma and serum for hormone assays. Plasma ACTH and serum cortisol concentrations were determined by radioimmunoassay. Leukocyte mRNA expression of IL-1β IL-6, IL-8, IL-10, and TNF-α was determined using RT-PCR.

RESULTS

Cortisol concentrations were greater (P < .05) in foals at admission than at other time points. The expressions of IL-8 and IL-10 mRNA were lower (P < .05) at each time point in septic than in nonseptic foals. Among septic foals, ACTH was positively associated (P = .0026) with IL-6 mRNA expression.

CONCLUSIONS

Sepsis influences secretion of the HPA axis hormones and expression of cytokines in foals. A positive association with the HPA axis and IL-6 expression was detected. The clinical importance of these findings requires additional study.

Serum interleukin-6 (IL-6) and IL-10 concentrations in normal and septic neonatal foals

Previously it was reported that compared to surviving septic foals, non-surviving foals had a 35-fold increase in interleukin-10 (IL-10) and 15-fold increase in IL-6 gene expression in their peripheral blood mononuclear cells (PBMC). As gene expression profiles can be time-consuming, we sought to determine if serum IL-6 and IL-10 in foals would aid in the diagnosis and prognosis of septicemia. A prospective study of septic neonatal foals admitted to the Cornell University Equine Hospital during 2007 and 2008 was performed. Septicemia was confirmed in 15 foals using blood culture results and sepsis scores. Blood samples for measurement of serum IL-6 and IL-10 concentrations were collected at the time of admission (T0) and again 24 (T24) and 48 (T48) hours later. Blood samples from age-matched control foals (n=15) born at the Cornell Equine Park were obtained from foals 12-72h after birth (T0) and again 24 (T24) and 48 (T48) hours later. IL-6 and IL-10 concentrations were determined in the serum from dams of septic foals and serum and colostrum from dams of control foals. Serum IL-6 was also measured in healthy foals prior to ingestion of colostrum. Interleukin-6 was detected using an ELISA and IL-10 was detected using a bead-based fluorescent immunoassay. Group differences were detected using a Wilcoxon rank sum test with a Bonferroni correction applied to the p value. There were no significant differences in serum IL-10 concentration between the two groups of foals. Relative to control foals, septic foals had significantly lower serum IL-6 concentrations at all 3 time points. Relative to septic foals, control foals had significantly higher serum IL-6:IL-10 ratios. Serum IL-6 was undetectable in foals prior to ingestion of colostrum. However, colostral IL-6 concentration measured in the control mares was high (> or =215ng/mL) in all samples suggesting passive transfer of maternal IL-6 to the equine neonate. Colostral IL-10 was undetectable in 11/12 samples. Failure of passive transfer may directly influence the serum IL-6 concentration in septic foals. Neither serum IL-6 nor IL-10 alone, were useful diagnostic indices of sepsis in equine neonates. Although the number of animals involved in this study was too small for the identification of a concrete value, the serum IL-6:IL-10 ratio is likely to provide a valuable prognosticator for neonatal septicemia.

The mitochondria-targeted antioxidant MitoQ protects against organ damage in a lipopolysaccharide-peptidoglycan model of sepsis

Sepsis is characterised by a systemic dysregulated inflammatory response and oxidative stress, often leading to organ failure and death. Development of organ dysfunction associated with sepsis is now accepted to be due at least in part to oxidative damage to mitochondria. MitoQ is an antioxidant selectively targeted to mitochondria that protects mitochondria from oxidative damage and which has been shown to decrease mitochondrial damage in animal models of oxidative stress. We hypothesised that if oxidative damage to mitochondria does play a significant role in sepsis-induced organ failure, then MitoQ should modulate inflammatory responses, reduce mitochondrial oxidative damage, and thereby ameliorate organ damage. To assess this, we investigated the effects of MitoQ in vitro in an endothelial cell model of sepsis and in vivo in a rat model of sepsis. In vitro MitoQ decreased oxidative stress and protected mitochondria from damage as indicated by a lower rate of reactive oxygen species formation (P=0.01) and by maintenance of the mitochondrial membrane potential (P<0.005). MitoQ also suppressed proinflammatory cytokine release from the cells (P<0.05) while the production of the anti-inflammatory cytokine interleukin-10 was increased by MitoQ (P<0.001). In a lipopolysaccharide-peptidoglycan rat model of the organ dysfunction that occurs during sepsis, MitoQ treatment resulted in lower levels of biochemical markers of acute liver and renal dysfunction (P<0.05), and mitochondrial membrane potential was augmented (P<0.01) in most organs. These findings suggest that the use of mitochondria-targeted antioxidants such as MitoQ may be beneficial in sepsis.

Interleukin-6 and lipopolysaccharide-binding protein in acute appendicitis in children

The aim of the study was to evaluate the diagnostic accuracy of interleukin-6 (IL-6) and lipopolysaccharide-binding protein (LBP) in children with acute appendicitis (AA) and to compare this with the diagnostic accuracy of routinely used C-reactive protein (CRP) and white blood cell (WBC) count. Eighty-two consecutive children admitted to our Department because of suspected AA were enrolled in this prospective study and classified into two groups: group 1 (49 children who underwent surgery for AA) and group 2 (33 children with no surgery with diagnosis of non-specific abdominal pain or sonographic mesenteric lymphadenitis). There were no negative appendectomies during the time of the study. The patients were further classified into three subgroups: subgroup 1A (43 patients with advanced AA), subgroup 2A (11 patients with mesenteric lymphadenitis) and subgroup 2B (10 patients with non-specific abdominal pain). The perforation rate was 32.7 %. WBC count and serum CRP, IL-6 and LBP were measured on admission. Area under receiver operating characteristic (ROC) curve (AUC), sensitivity, specificity and predictive values were evaluated. Serum IL-6 and LBP were significantly higher in group 1 than in group 2. The highest AUC for AA was that for IL-6 (0.776), followed by WBC count (0.684), CRP (0.637) and LBP (0.635). In conclusion, only IL-6, determined on admission, showed medium diagnostic accuracy, while other laboratory markers showed low diagnostic accuracy for AA in children. The new laboratory markers therefore do not significantly improve the diagnosis of AA.

Mechanisms of mortality in early and late sepsis

A recent hypothesis postulates that sepsis moves through different phases, with periods of enhanced inflammation alternating with periods of immune suppression. In this study we determined the levels of inflammation present during early and late septic deaths to examine whether death was due to hyperinflammation or immunosuppression. The murine model of sepsis induced by cecal ligation and puncture (CLP) was used. Complete blood counts, plasma interleukin-6 (IL-6) levels, and body weights were determined. Mice that died within the first 4 days had increased plasma levels of IL-6, indicating that there was activation of the immune system. Cecal resection on day 4 after CLP resulted in decreased abscess size, lower circulating neutrophil counts, decreased anemia, and improved survival compared to the results for mice that received only antibiotic and fluid therapy. All of the mice that died in the chronic phase of infection (after day 4) had positive peritoneal cultures containing significantly more bacteria than the cultures for surviving mice. After day 4, none of the surviving mice exhibited increases in the plasma levels of IL-6. Dying mice exhibited mixed IL-6 responses; for 41% of the mice there was never an increase in the IL-6 levels in the chronic phase, while for other mice the levels of IL-6 transiently increased prior to death. Peritoneal macrophages were obtained in the late phase of sepsis from moribund and healthy mice and were stimulated ex vivo. The cells from the moribund mice produced significantly less IL-6 than the cells obtained from healthy mice produced. These results indicate that in mice that die in the early phase there is uniformly increased inflammation. However, during the chronic phase of sepsis, some mice die with evidence of immunosuppression (increased bacterial growth and low IL-6 levels), while other mice die with immunostimulation (high IL-6 levels and bacterial growth). Determining the inflammatory status of individual patients may help guide appropriate, targeted therapy.