Endogenous mediators in emergency department patients with presumed sepsis: are levels associated with progression to severe sepsis and death?

Biomarkers to Predict Multiorgan Distress Syndrome and Acute Kidney Injury in Critically Ill Surgical Patients

Background and Objectives: Critically ill surgical patients are susceptible to various postoperative complications, including acute kidney injury (AKI) and multiorgan distress syndrome (MODS). These complications intensify patient suffering and significantly increase morbidity and mortality rates. This study aimed to identify the biomarkers for predicting AKI and MODS in critically ill surgical patients. Materials and Methods: We prospectively enrolled critically ill surgical patients admitted to the intensive care unit via the emergency department between July 2022 and July 2023. A total of 83 patients were recruited, and their data were used to analyze MODS. Three patients who showed decreased creatinine clearance at the initial presentation were excluded from the analysis for AKI. Patient characteristics and laboratory parameters including white blood cell (WBC) count, neutrophil count, delta neutrophil index, urine and serum β2-microglobulin, and urine serum mitochondrial DNA copy number (mtDNAcn) were analyzed to determine the reliable biomarker to predict AKI and MODS. Results: The following parameters were independently correlated with MODS: systolic blood pressure (SBP), initial neutrophil count, and platelet count, according to a logistic regression model. The optimal cut-off values for SBP, initial neutrophil count, and platelet count were 113 mmHg (sensitivity 66.7%; specificity 73.9%), 8.65 (X3) (109/L) (sensitivity 72.2%; specificity 64.6%), and 195.0 (X3) (109/L) (sensitivity 66.7%; specificity 81.5%), respectively. According to the logistic regression model, diastolic blood pressure (DBP) and initial urine mtDNAcn were independently correlated with AKI. The optimal cut-off value for DBP and initial urine mtDNAcn were 68.5 mmHg (sensitivity 61.1%; specificity 79.5%) and 1225.6 copies/μL (sensitivity 55.6%; specificity 95.5%), respectively. Conclusions: SBP, initial neutrophil count, and platelet count were independent predictors of MODS in critically ill patients undergoing surgery. DBP and initial urine mtDNAcn levels were independent predictors of AKI in critically ill surgical patients. Large-scale multicenter prospective studies are needed to confirm our results.

Examination of antimicrobial effect of fluoxetine in experimental sepsis model: An in vivo study

Since most infectious diseases can develop into sepsis, it is still a major medical problem. Some in-vivo studies showed promising properties of fluoxetine in the treatment of infections. This study aims the antimicrobial effect of fluoxetine on the inflammatory process used in the treatment of sepsis-modeled rats. Besides, to investigate the efficacy of fluoxetine on modifying the antibiotic effect of imipenem in the inflammatory response. An experimental sepsis model was divided into negative control, positive control, fluoxetine 5 mg/kg, imipenem 60 mg/kg, and combined (fluoxetine; imipenem). Procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), lactate, myeloperoxidase activity (MPO), the inflammation markers interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alfa (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) levels were measured by enzyme-linked immunosorbent assay method. Oxidative stress markers, total oxidant status (TOS), total antioxidant status (TAS), total thiol (TT), and native thiol (NT) were measured using photometric methods. Oxidative stress index (OSI) was calculated according to TAS and TOS levels. The statistical analysis was performed by Statistical Package for Social Sciences version 22.0. After treatment with fluoxetine, imipenem, and combined groups, IL-1β, IL-6, TNF-α, MPO activity, MCP-1, hs-CRP, PCT, lactate, and the oxidative stress markers OSI, and disulfide levels were decreased (p < 0.05). The TT, NT, and TAS levels significantly statistically increased (p < 0.05). This research demonstrates that fluoxetine has effects as anti-inflammatory and antioxidant, and the combined treatment with antibioticum imipenem indicates positive synergistic effects in the experimental sepsis model.

Proinflammatory cytokines levels in sepsis and healthy volunteers, and tumor necrosis factor-alpha associated sepsis mortality: A systematic review and meta-analysis

BACKGROUND

Sepsis is a global health challenge associated with significant morbidity and mortality. Detrimental sepsis effects are attributed to excessive inflammation or a "cytokine storm." However, anti-inflammation therapies have failed to lower sepsis mortality. We aim to characterize levels of key inflammatory cytokines in patients with sepsis and compare levels with those in healthy individuals and relate tumor necrosis factor (TNF) α levels to patient characteristics and outcomes.

METHODS

We performed a systematic review and meta-analysis. Medline, Embase, Cochrane Library, and Web of Science Core Collection databases were searched between 1985 and May 2020. Analysis was restricted to studies in English. We included randomized controlled trials (RCTs), controlled trials, cohort studies, case series, and cross-sectional studies that reported mean levels of cytokines in the circulation thought to be relevant for sepsis pathogenesis. We also evaluated concentrations of these cytokines in healthy individuals. The Quality in Prognosis Studies tool was used to assess the methodological quality of included studies. We extracted summary data from published reports. Data analyses were performed using a random-effects model to estimate pooled odds ratios (OR) with 95% confidence intervals for cytokine levels and mortality. This systematic review is registered in PROSPERO (CRD42020179800).

FINDINGS

We identified 3654 records, and 104 studies were included with a total of 3250 participants. The pooled estimated mean TNFα concentration in sepsis patients was 58.4 pg/ml (95% Confidence Interval or CI 39.8-85.8 pg/ml), and in healthy individuals was 5.5 pg/ml (95% CI 3.8-8.0 pg/ml). Pooled estimate means for IL-1β and IFN-γ in sepsis patients were 21.8 pg/ml and 63.3 pg/ml, respectively. Elevated TNFα concentrations associated with increased 28-day sepsis mortality (p = 0.001). In subgroup analyses, we did not detect an association between TNFα levels and sepsis source, sepsis severity, or sequential organ failure assessment (SOFA) score. A TNF-α cutoff level ≥14.7 pg/ml separated sepsis patients from healthy individuals with a sensitivity of 82.6%, a specificity of 91.7%, and a likelihood ratio of 9.9.

INTERPRETATION

Sepsis mean TNFα concentration is increased approximately 10-fold compared to mean concentration in healthy individuals, and TNFα associated with sepsis mortality but not sepsis severity. The concept that elevated cytokines cause sepsis should be revisited in the context of these data.

FUNDING

None.

The Fluctuations of Leukocytes and Circulating Cytokines in Septic Humanized Mice Vary With Outcome

Sepsis remains a major challenge in translational research given its heterogeneous pathophysiology and the lack of specific therapeutics. The use of humanized mouse chimeras with transplanted human hematopoietic cells may improve the clinical relevance of pre-clinical studies. However, knowledge of the human immuno-inflammatory response during sepsis in humanized mice is scarce; it is unclear how similar or divergent mouse and human-origin immuno-inflammatory responses in sepsis are. In this study, we evaluated the early outcome-dependent immuno-inflammatory response in humanized mice generated in the NSG strain after cecal ligation and puncture (CLP) sepsis. Mice were observed for 32 h post-CLP and were assigned to either predicted-to-die (P-DIE) or predicted-to-survive (P-SUR) groups for retrospective comparisons. Blood samples were collected at baseline, 6 and 24 h, whereas the bone marrow and spleen were collected between 24 and 32 h post-CLP. In comparison to P-SUR, P-DIE humanized mice had a 3-fold higher frequency of human splenic monocytes and their CD80 expression was reduced by 1.3-fold; there was no difference in the HLA-DR expression. Similarly, the expression of CD80 on the bone marrow monocytes from P-DIE mice was decreased by 32% (p < 0.05). Sepsis induced a generalized up-regulation of both human and murine plasma cytokines (TNFα, IL-6, IL-10, IL-8/KC, MCP-1); it was additionally aggravated in P-DIE vs. P-SUR. Human cytokines were strongly overridden by the murine ones (approx. ratio 1:9) but human TNFα was 7-fold higher than mouse TNFα. Interestingly, transplantation of human cells did not influence murine cytokine response in NSG mice, but humanized NSG mice were more susceptible to sepsis in comparison with NSG mice (79 vs. 33% mortality; p < 0.05). In conclusion, our results show that humanized mice reflect selected aspects of human immune responses in sepsis and therefore may be a feasible alternative in preclinical immunotherapy modeling.

Predictors of early progression to severe sepsis or shock among emergency department patients with nonsevere sepsis

Background

Progression from nonsevere sepsis—i.e., sepsis without organ failure or shock—to severe sepsis or shock among emergency department (ED) patients has been associated with significant mortality. Early recognition in the ED of those who progress to severe sepsis or shock during their hospital course may improve patient outcomes. We sought to identify clinical, demographic, and laboratory parameters that predict progression to severe sepsis, septic shock, or death within 96 h of ED triage among patients with initial presentation of nonsevere sepsis.

Methods

This is a retrospective cohort of patients presenting to a single urban academic ED from November 2008 to October 2010. Patients aged 18 years or older who met criteria for sepsis and had a lactate level measured in the ED were included. Patients were excluded if they had any combination of the following: a systolic blood pressure <90 mmHg upon triage, an initial whole blood lactate level ≥4 mmol/L, or one or more of a set of predefined signs of organ dysfunction upon initial assessment. Disease progression was defined as the development of any combination of the aforementioned conditions, initiation of vasopressors, or death within 96 h of ED presentation. Data on predefined potential predictors of disease progression and outcome measures of disease progression were collected by a query of the electronic medical record and via chart review. Logistic regression was used to assess associations of potential predictor variables with a composite outcome measure of sepsis progression to organ failure, hypotension, or death.

Results

In this cohort of 582 ED patients with nonsevere sepsis, 108 (18.6 %) experienced disease progression. Initial serum albumin <3.5 mg/dL (OR 4.82; 95 % CI 2.40–9.69; p < 0.01) and a diastolic blood pressure <52 mmHg at ED triage (OR 4.59; 95 % CI 1.57–13.39; p < 0.01) were independently associated with disease progression to severe sepsis or shock within 96 h of ED presentation. There were no deaths within 96 h of ED presentation.

Conclusions

In our patient cohort, serum albumin <3.5 g/dL and an ED triage diastolic blood pressure <52 mmHg independently predict early progression to severe sepsis or shock among ED patients with presumed sepsis.

Immunoinflammatory response in critically ill patients: severe sepsis and/or trauma

Immunoinflammatory response in critically ill patients is very complex. This review explores some of the new elements of immunoinflammatory response in severe sepsis, tumor necrosis factor-alpha in severe acute pancreatitis as a clinical example of immune response in sepsis, immune response in severe trauma with or without secondary sepsis, and genetic aspects of host immuno-inflammatory response to various insults in critically ill patients.

Several Cytokines and Protein C Levels with the Apache II Scoring System for Evaluation of Patients with Sepsis

OBJECTIVE

We investigated whether determination IL-6, IL-8, IL-1beta and TNF-alpha at baseline, total protein C (PC) levels at time of admission and 48 hours after initiation could complement the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system to identify patients with sepsis, severe sepsis or septic shock for clinical outcome.

MATERIAL AND METHODS

The study was carried out prospectively. 60 consecutive patients with sepsis, severe sepsis or septic shock were included. Blood samples were obtained at baseline and 48 hours after initiation. Cytokines and PC levels in plasma were measured with an enzyme-linked immunoabsorbent assay (ELISA). APACHE II score was calculated on admission.

RESULTS

Baseline IL-6 levels and PC levels 48 hours after initiation were predictive of increased mortality (p=0.016, p=0.044 respectively). Baseline IL-6, IL-8 and TNF-alpha baseline levels correlate with the severity of physiologic insult, as determined by the APACHE II score. However, our multiple logistic regression analysis of these did not reveal any predictive value in combination with the APACHE II score.

CONCLUSION

Determination of baseline IL-6 and PC 48 hours after initiation were of predictive value for prognostic evaluation of septic patients, but did not significantly increase predictive power of the APACHE scoring system to identify patients with sepsis for fatal clinical outcome.

Functional status does not predict complicated clinical course in older adults in the emergency department with infection

OBJECTIVES

To identify the relationship between functional status and complicated clinical course in older adults in the emergency department (ED) with suspected infection and to identify other independent predictors of complicated clinical course.

DESIGN

A prospective observational cohort study.

SETTING

An academic, tertiary care ED with 70,000 visits per year.

PARTICIPANTS

Aged 65 and older, blood cultures obtained in the ED, and final ED physician diagnosis of acute infection.

MEASUREMENTS

Functional status was obtained using the Older Americans Resources Scale (OARS). Complicated clinical course was defined as in-hospital mortality, need for intensive care unit (ICU)-level care, or worsening in sepsis criteria within 48 hours. Analysis was performed using multivariable logistic regression.

RESULTS

One hundred five participants were enrolled, 34 with the primary outcome. OARS was not predictive of complicated clinical course in univariate (P = .13) or multivariable (P = .90) models. An OARS score of 25 or less was also not significant (P = .22). Independent predictors were immunosuppression (odds ratio (OR) = 3.45, 95% confidence interval (CI) = 1.06-11.20), systolic blood pressure (OR = 0.98, 95% CI = 0.96-1.00), pulse (OR = 1.03, 95% CI = 1.00-1.06), metabolic acidosis (OR = 3.46, 95% CI = 1.08-11.09), severe sepsis or septic shock (OR = 10.24, 95% CI = 1.44-72.79), and suspected bloodstream infection (OR = 3.56, 95% CI = 1.13-11.16).

CONCLUSION

For older adults admitted to the ED with infection, functional status did not predict complicated clinical course, but several other variables were predictive, including immunosuppression, several variables associated with hypoperfusion, and suspected bloodstream infection. Emergency physicians could consider these variables as potential indicators of complicated clinical course when making disposition decisions for this population.

Monocyte mRNA phenotype and adverse outcomes from pediatric multiple organ dysfunction syndrome

Impairment of the ability to mount an inflammatory response is associated with death from adult critical illness. This phenomenon, characterized by reduced monocyte production of proinflammatory mediators such as tumor necrosis factor alpha (TNF-alpha), is poorly understood in children. We hypothesized that differential expression of inflammation-related genes would be seen in monocytes from children with adverse outcomes from multiple organ dysfunction syndrome (MODS). Ex vivo lipopolysaccharide (LPS)-induced TNF-alpha production and plasma cytokines were prospectively measured biweekly in children with dysfunction of two or more organs. Concomitantly, monocyte expression of 28 pro- and anti-inflammatory genes [cytokines, Toll-like receptor (TLR)/nuclear factor kappaB (NF-kappaB) signaling pathway members, inflammasome elements] was measured. Thirty children (22 survivors, eight nonsurvivors) were evaluated. High mRNA levels for interleukin (IL)-10, IL-1 receptor-associated kinase (IRAK-M), and the putative inflammasome inhibitor pyrin were associated with death (p < or = 0.02). Plasma IL-10 levels were higher and ex vivo TNF-alpha production was lower in nonsurvivors (p < 0.05). Among survivors, high mRNA levels for IL-10, IRAK-M, pyrin, IRAK1, or TLR4 were associated with longer durations of pediatric intensive care unit (PICU) stay and mechanical ventilation (p < or = 0.02). These data suggest that adverse outcomes from pediatric MODS are associated with an anti-inflammatory monocyte mRNA phenotype. Future studies are warranted to explore mechanisms of immunodepression in pediatric critical illness.

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.

Circulating cytokine/inhibitor profiles reshape the understanding of the SIRS/CARS continuum in sepsis and predict mortality

Mortality in sepsis remains unacceptably high and attempts to modulate the inflammatory response failed to improve survival. Previous reports postulated that the sepsis-triggered immunological cascade is multimodal: initial systemic inflammatory response syndrome (SIRS; excessive pro-, but no/low anti-inflammatory plasma mediators), intermediate homeostasis with a mixed anti-inflammatory response syndrome (MARS; both pro- and anti-inflammatory mediators) and final compensatory anti-inflammatory response syndrome (CARS; excessive anti-, but no/low proinflammatory mediators). To verify this, we examined the evolution of the inflammatory response during the early phase of murine sepsis by repetitive blood sampling of septic animals. Increased plasma concentrations of proinflammatory (IL-6, TNF, IL-1beta, KC, MIP-2, MCP-1, and eotaxin) and anti-inflammatory (TNF soluble receptors, IL-10, IL-1 receptor antagonist) cytokines were observed in early deaths (days 1-5). These elevations occurred simultaneously for both the pro- and anti-inflammatory mediators. Plasma levels of IL-6 (26 ng/ml), TNF-alpha (12 ng/ml), KC (33 ng/ml), MIP-2 (14 ng/ml), IL-1 receptor antagonist (65 ng/ml), TNF soluble receptor I (3 ng/ml), and TNF soluble receptor II (14 ng/ml) accurately predicted mortality within 24 h. In contrast, these parameters were not elevated in either the late-deaths (day 6-28) or survivors. Surprisingly, either pro- or anti-inflammatory cytokines were also reliable in predicting mortality up to 48 h before outcome. These data demonstrate that the initial inflammatory response directly correlates to early but not late sepsis mortality. This multifaceted response questions the use of a simple proinflammatory cytokine measurement for classifying the inflammatory status during sepsis.

Cytokine expression profile over time in severely burned pediatric patients

A severe burn leads to hypermetabolism and catabolism resulting in compromised function and structure of essential organs. The massive release of cytokines is implicated in this hypermetabolic response. The aim of the present study was to compare cytokine expression profiles from severely burned children without signs of infections or inhalation injury (n = 19) to the cytokine profiles from normal, noninfected, nonburned children (n = 14). The Bio-Plex suspension array system was used to measure the concentration of 17 cytokines. The expression of proinflammatory and anti-inflammatory cytokines was maximal during the first week after thermal injury. Significant increases were measured for 15 mediators during the first week after thermal injury: interleukin (IL) 1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 p70, IL-13, IL-17, interferon gamma, monocyte chemoattractant protein 1, macrophage inflammatory protein 1beta, and granulocyte colony-stimulating factor (P < 0.05). Granulocyte-macrophage colony-stimulating factor was significantly increased during the second week after burn (P < 0.05). Within 5 weeks, the serum concentrations of most cytokines decreased, approaching normal levels. When compared with the cytokine levels measured in normal children, a total of 16 cytokines were significantly altered (P < 0.05). After severe burn, a specific cytokine expression profile is observed in patients without complications such as inhalation injury or sepsis. The cytokine concentrations decrease during 5 weeks after burn but remain elevated over nonburned values. Furthermore, the elevation in most serum cytokine levels during the first week after burn may indicate a potential window of opportunity for therapeutic intervention.

National study of emergency department visits for sepsis, 1992 to 2001

STUDY OBJECTIVE

Epidemiologic data on emergency department (ED) patients with sepsis are limited. Inpatient discharge records from 1979 to 2000 show that hospitalizations for sepsis are increasing. We examine the epidemiology of sepsis in US EDs and the hypothesis that sepsis visits are increasing.

METHODS

The National Hospital Ambulatory Medical Care Survey data (1992 to 2001) provided nationally representative estimates of frequency and disposition in adult ED visits for sepsis. Sepsis visits were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes; severe sepsis was defined as sepsis in conjunction with organ failure.

RESULTS

Of 712 million adult visits during the 10-year period, approximately 2.8 million (0.40%, 95% confidence interval [CI] 0.33% to 0.46%) were related to sepsis. We found no significant increase in overall ED visits for sepsis from 1992 to 2001 (P for trend=.09). ED patients with sepsis were more likely to be elderly, non-Hispanic, and publicly insured and to arrive by ambulance compared with nonsepsis patients (all P<.01). The overall admission rate was 87% (95% CI 82% to 92%), with only 12% (95% CI 8% to 16%) of patients admitted to the ICU. The most frequent codiagnoses were pneumonia (13%), urinary tract infection (13%), and dehydration (11%). Severe sepsis accounted for 8% (95% CI 5% to 11%) of sepsis visits, for an annual incidence of 0.01%; 98% of patients with severe sepsis were admitted.

CONCLUSION

In contrast to data from hospital discharges, ED visits for sepsis demonstrated no increase. Most ED visits for sepsis resulted in admission to non-critical care units.

PEGylated helper-dependent adenoviral vectors: highly efficient vectors with an enhanced safety profile

Transgene expression from helper-dependent adenoviral (HD-Ad) vectors is effective and long lasting, but not permanent. Their use is also limited by the host response against capsid proteins that precludes successful gene expression upon readministration. In this report, we test the hypothesis that PEGylation of HD-Ad reduces its toxicity and promotes transgene expression upon readministration. PEGylation did not compromise transduction efficiency in vitro and in vivo and reduced peak serum IL-6 levels two-fold. IL-12 and TNF-alpha levels were reduced three- and seven-fold, respectively. Thrombocytopenia was not detected in mice treated with the PEGylated vector. Serum transaminases were not significantly elevated in mice treated with either vector. Mice immunized with 1 x 10(11) particles of unmodified HD-Ad expressing human alpha-1 antitrypsin (hA1AT) were rechallenged 28 days later with 8 x 10(10) particles of unmodified or PEG-conjugated vector expressing beta-galactosidase. Trace levels of beta-galactosidase (52.23+/-19.2 pg/mg protein) were detected in liver homogenates of mice that received two doses of unmodified HD-Ad. Mice rechallenged with PEGylated HD-Ad produced significant levels of beta-galactosidase (5.1+/-0.4 x 10(5) pg/mg protein, P=0.0001). This suggests that PEGylation of HD-Ad vectors may be appropriate for their safe and efficient use in the clinic.

Correction of perioperative hypothermia decreases experimental sepsis mortality by modulating the inflammatory response

OBJECTIVE

The objective of this study was to investigate if the correction of perioperative hypothermia improves sepsis survival.

DESIGN

Mice with anesthesia-induced perioperative hypothermia had sepsis induced by cecal ligation and puncture and were treated with fluid resuscitation and antibiotics. The mice were either warmed (35 degrees C) or kept at room temperature for 1 hr in the immediate postoperative period.

SETTING

This study was conducted at a university research laboratory.

SUBJECTS

This study included adult, female outbred mice.

INTERVENTIONS

Immediately after surgery, mice were randomized to 1 hr of warming or maintained at room temperature. Warming was accomplished by placing the mice in a cage preheated to 35 degrees C.

MEASUREMENT AND MAIN RESULTS

The anesthesia-induced hypothermia resolved within 10 hrs, and perioperative warming reestablished normothermia within 1 hr. Restoring normothermia improved sepsis survival from 42% to 60% (p < .02). Warming also significantly corrected the changes in body weight, reflecting improved overall physiological status. To examine the mechanism of this beneficial response, plasma levels of interleukin-6 were assessed. Warming was associated with a decrease in interleukin-6 levels in both those mice that died as well as survivors, reflecting a blunting but not complete inhibition of the inflammatory response. Among surviving mice, warming also significantly increased the peripheral blood cell count, including the neutrophils, an indication that warming augmented innate immunity.

CONCLUSIONS

Correction of perioperative hypothermia improves survival after sepsis by appropriately modulating the early inflammatory response.

Serial monitoring of interleukin-1?, soluble interleukin-2 receptor and lipopolysaccharide binding protein levels after death

We prospectively monitored the postmortem course of interleukin-1beta (IL-1beta), soluble interleukin-2 receptor (sIL-2R) and lipopolysaccharide binding protein (LBP) in septic and non-septic fatalities to evaluate their potential as biochemical postmortem markers of sepsis. Serum concentrations were determined by chemiluminescent immunometric assays. In both the sepsis group and the control group a postmortem increase of IL-1beta levels with the progression of time after death was observed, in both groups mainly starting from the reference concentration of healthy individuals (5 pg/ml) and with no significant differences at later time points postmortem. SIL-2R (reference limit 1,000 U/ml) was highly elevated in all individuals included in the sepsis group at all time points postmortem with statistically significant differences between the sepsis and control groups (p<0.01). An excessive postmortem decrease of sIL-2R serum levels associated with progression of time after death was observed in all cases included in the sepsis group in contrast to just 1 out of 16 control cases. LBP (reference limit <10 g/ml) was elevated in all sepsis cases whereas in the control group LBP levels were below 10 microg/ml in 88%. The postmortem time course of LBP serum concentrations showed a continuous increase in both the sepsis and control groups. We conclude that sIL-2R and LBP seem to represent appropriate diagnostic tools for the postmortem diagnosis of sepsis in forensic autopsy practice. sIL-2R serum levels above 1,000 U/ml and LBP serum levels above 10 microg/ml in peripheral venous blood obtained in the early postmortem interval can be regarded as diagnostic hints for an underlying septic condition in a deceased person.

Cytometric bead assay of cytokines in sepsis: A clinical evaluation

BACKGROUND

The clinical relevancy of an attractive new multiparametric method, cytometric beads assay (CBA), was evaluated for the monitoring of cytokines in sepsis.

METHODS

A total of 52 samples (26 patients) were simultaneously tested by CBA and chemiluminescence (IL-6, IL-8, IL-1beta, and TNFalpha) or ELISA (IL-10, IL-12 p40, IL-12 p70, and soluble TNFalpha-RI).

RESULTS

CBA standard curves were linear from 20-5,000 ng/L except for IL-1beta (40-5,000 ng/L). IL-6 and IL-8 were detected in 41 and 48 samples (44-5,000 ng/L and 22-5,000 ng/L), respectively, and out of range in six samples. IL-10 and IL-1beta were detected in 14 and 15 samples (21-1,548 ng/L and 29-582 ng/L), respectively. TNFalpha was rarely detected, and IL-12 p70 was never detected. Accuracy and repeatability were good (CV for IL-6 was 2.1-8.7%; for IL-8 3.7-5.3%; for IL-10 2.5-9.1%; for IL-12 5.2-6.5%; for IL-1 beta 4-12%; and for TNFalpha 3-19.3%). Reproducibility of four standard curves and 20 samples (-1.1 to +1.03%) was excellent between tests done at two- to six-week intervals. CBA values were correlated (r2 > 0.89; P < 0.001) with our reference methods, but were lower on CBA (TNFalpha 45% +/- 8; IL-6 49% +/- 7), probably due to interactions with patients' serum, as confirmed by spiking diluted standards in one patient's serum with end stage renal failure and high levels of TNF soluble receptor (i.e., TNFalpha levels 34 and 21%).

CONCLUSIONS

Finally, these results suggest that IL-6, IL-8, IL-1beta, and Il-10 are clinically promising for sepsis evaluation. However, sensitivity of TNFalpha has to be improved and IL-12 p70 should be replaced with more relevant parameters such as TNF-R, procalcitonin, or neopterin.

Procalcitonin as a marker of bacterial infection in the emergency department: an observational study

Introduction

Procalcitonin (PCT) has been proposed as a marker of infection in critically ill patients; its level is related to the severity of infection. We evaluated the value of PCT as a marker of bacterial infection for emergency department patients.

Methods

This prospective observational study consecutively enrolled 120 adult atraumatic patients admitted through the emergency department of a 3000-bed tertiary university hospital in May 2001. Fifty-eight patients were infected and 49 patients were not infected. The white blood cell counts, the serum C-reactive protein (CRP) level (mg/l), and the PCT level (ng/ml) were compared between the infected and noninfected groups of patients.

Results

A white blood cell count >12,000/mm³ or <4000/mm³ was present in 36.2% of the infected patients and in 18.4% of the noninfected patients. The best cut-off serum levels for PCT and CRP, identified using the Youden's Index, were 0.6 ng/ml and 60 mg/l, respectively. Compared with CRP, PCT had a comparable sensitivity (69.5% versus 67.2%), a lower specificity (64.6% versus 93.9%), and a lower area under the receiver operating characteristic curve (0.689 versus 0.879). PCT levels, but not CRP levels, were significantly higher in bacteremic and septic shock patients. Multivariate logistic regression identified that a PCT level ≥ 2.6 ng/ml was independently associated with the development of septic shock (odds ratio, 38.3; 95% confidence interval, 5.6–263.5; P < 0.001).

Conclusions

PCT is not a better marker of bacterial infection than CRP for adult emergency department patients, but it is a useful marker of the severity of infection.

Inflammatory status in sepsis alters efficacy of interleukin-18 binding protein therapy

OBJECTIVE

Sepsis remains a serious clinical problem, and multiple attempts at blocking inflammation have failed to decrease mortality rate. Interleukin-18 has been demonstrated to be an important component of the innate immune response to bacterial infections.

DESIGN

Previous work demonstrated that elevated plasma concentrations of interleukin-6 obtained in the first 6 hrs of sepsis predict a worse outcome. Mice were subjected to cecal ligation and puncture and, on the basis of the plasma concentration of interleukin-6, were randomized to receive either interleukin-18 binding protein or vehicle approximately 8 hrs after the onset of sepsis.

SETTING

University research laboratory.

SUBJECTS

Adult, female BALB/c mice.

INTERVENTIONS

We sought to determine the role of interleukin-18 in sepsis by blocking its biological activity with the interleukin-18 binding protein in the murine model of sepsis induced by cecal ligation and puncture.

MEASUREMENTS AND MAIN RESULTS

In this study, elevated plasma concentrations of interleukin-6 were associated with a worse outcome. Treatment with interleukin-18 binding protein decreased inflammation as determined by lower concentrations of plasma interleukin-6 obtained 48 hrs after the onset of sepsis. In mice with increased risk of dying, interleukin-18 binding protein slightly decreased mortality rate. However, in those mice with a predicted low mortality rate, interleukin-18 binding protein significantly increased mortality rate.

CONCLUSIONS

In this study, mice at low risk of death due to sepsis had decreased survival when treated with interleukin-18 binding protein. These results have potential implications for the use of interleukin-18 binding protein for treatment of chronic inflammatory conditions since it may place the host at increased risk of infectious complications.

Prostaglandin E2 mediates growth arrest in NFS-60 cells by down-regulating interleukin-6 receptor expression

Interleukin-6 (IL-6), a potent myeloid mitogen, and the immunosuppressive prostanoid prostaglandin E2 (PGE2) are elevated following thermal injury and sepsis. We have previously demonstrated that bone marrow myeloid commitment shifts toward monocytopoiesis and away from granulocytopoiesis during thermal injury and sepsis and that PGE2 plays a central role in this alteration. Here we investigated whether PGE2 can modulate IL-6-stimulated growth in the promyelocytic cell line, NFS-60, by down-regulating IL-6 receptor (IL-6r) expression. Exposure of NFS-60 cells to PGE2 suppressed IL-6-stimulated proliferation as well as IL-6r expression. Receptor down-regulation is functionally significant since IL-6-induced signal transduction through activators of transcription (STAT)-3 is also decreased. Down-regulation of IL-6r correlated with the ability of PGE2 to arrest cells in the G0/G1 phase of the cell cycle. PGE2 appears to signal through EP2 receptors. Butaprost (EP2 agonist) but not sulprostone (EP3 agonist) inhibited IL-6-stimulated proliferation. In addition, an EP2 antagonist (AH6809) alleviated the anti-proliferative effects of PGE2. NFS-60 cells express predominantly EP2 and EP4 receptors. While PGE2 down-regulated both the IL-6r protein and mRNA expression, it had no influence on EP2 or EP4 mRNA expression. The present study demonstrates that PGE2 is a potent down-regulator of IL-6r expression and thus may provide a mechanistic explanation for the granulocytopenia seen in thermal injury and sepsis.

Valor de las citocinas proinflamatorias como factor de predicción de sepsis y mortalidad en el anciano con fiebre

BACKGROUND AND OBJECTIVE

Proinflammatory cytokines (IL-1beta, IL-6, TNF-alpha) are excellent predictive factors of tissue damage, inflammation and infection. However, there is not sufficient data about their usefulness in elderly patients with acute septic pathology. Our objective was to identify the cytokines related to bacteremia and those that predicted a bad prognosis in elderly patients.

PATIENTS AND METHOD

Prospective study carried out during 1999. Patients aged >= 60 years with temperature >= 38 C admitted to the emergency ward. We determined IL-1beta, IL-6, TNF-alpha and C-reactive protein (CRP); cultures were done according to the infectious source. On the 4th day, cytokines and CRP were recorded again. The follow-up was completed until cure or death.

RESULTS

50 patients were included (29 males). Median age was 75.6 (SD: 8.98). The etiology was infectious in 44 (88%): respiratory in 29 (66%), urinary in 8 (18%) and other sources in 7. Thirteen patients had bacteremia (32%): Escherichia coli (4), Streptococcus pneumoniae (5) and others (4). Ten patients died (20%). Median values on admission were CRP : 6.67 mg/dl (NV 0.8), TNF-alpha: 29 pg/ml (NV 0-20), IL-1beta: 7 pg/ml (NV 15) and IL-6: 121 pg/ml (NV 5). 4th day values were: 4.23 mg/dl, 22 pg/ml, 1 pg/ml and 41 pg/ml, respectively. The levels of IL-1b in the 2nd determination were significantly lower in females (p = 0.019). Initial TNF-alpha (p = 0.033), IL-1beta (p = 0.013) and IL-6 (p = 0.031) values were significantly higher in bacteremia patients. IL-6 values on the 4th day were higher in patients who died (p = 0.06). In patients who died, IL-6 levels were higher in the 2nd determination (p = 0.09).

CONCLUSIONS

Median values of all cytokines were higher in the bacteremia population. Patients who died showed higher levels of IL-6 on the 4th day.

Sudden death in an infant resulting from torsion of the uterine adnexa

A 2-month-old infant girl died suddenly as a result of torsion of the uterine adnexa. The infant was found unresponsive in bed and was pronounced dead shortly after her arrival at a hospital. There were no antecedent signs of illness. At autopsy, the right ovary and right fallopian tube were twisted and were dark purple, swollen, and necrotic. The right ovary was enlarged by a follicle cyst 4 cm in diameter, which likely precipitated the torsion. The mechanism of death was unclear but may have resulted from the release of cytokines produced in response to necrotic adnexal tissue. Fatal uterine adnexal torsion has been reported rarely in infants; in all those cases there were antecedent symptoms. Torsion of the uterine adnexa should be included in the differential diagnosis of sudden death in infancy.

Six at six: interleukin-6 measured 6 h after the initiation of sepsis predicts mortality over 3 days

Virtually of the all recent therapeutic interventions for treating sepsis have failed to improve survival. One potential explanation is that the heterogeneity of the immune response to the septic challenge is such that only a portion of the patients die as a result of excessive inflammation. The clinical trials lacked power because traditional measurements do not accurately identify these patients. Previous work has shown that higher levels of interleukin (IL)-6 are found in those mice that die from septic peritonitis; therefore, we sought to determine whether IL-6 measured 6 h after surgery could predict outcome. Adult, female BALB/c mice (n = 79) were subjected to cecal ligation and puncture with a 21-gauge needle and treated with imipenem in D5W every 12 h for 5 days, resulting in a homogenous population at the outset. Six hours after surgery, 20 microL of blood was obtained from the tail vein to measure IL-6. Mortality was followed for 21 days. Overall 3-day survival was 77%, and 21-day mortality was 56%. Plasma IL-6 levels >2,000 pg/mL were determined to predict mortality within the first 3 days with a sensitivity of 58% and specificity of 97%. To further refine the mortality prediction, body weight and a complete blood count were performed 24 hours after cecal ligation and puncture. Discriminate analysis indicated that a weighted formula combining body mass, lymphocyte, and platelet count would predict death with sensitivity of 83% and a specificity of 79%. We tested the value of the IL-6 prediction by surgically resecting the cecum in those animals with IL-6 > 2000 pg/mL, which resulted in a significant improvement in survival. These data demonstrate that IL-6 measured 6 h after injury accurately predicts mortality resulting from experimental sepsis. This measurement may be determined quickly so that therapy may be targeted only to those individuals at significant risk of dying and initiated within sufficient time to be effective.

Future challenges in preparing for and responding to bioterrorism events

The future success of our preparations for bioterrorism depends on many issues as presented in this article. If these issues are properly addressed, the resulting improvements in bioterrorism preparations will allow us to better deter and mitigate a bioterrorism incident and will also provide us with the added benefit of improvements in early detection, diagnosis, and treatment of natural disease outbreaks. Emergency physicians must take an active leading role in working with the various disciplines to produce a better-prepared community.

Relationship between cytokine mRNA expression and organ damage following cecal ligation and puncture

AIM: To investigate the role of cytokine gene expression in organ damage at different tissue sites during sepsis.

METHODS: Male NIH mice were subjected to cecal ligation and puncture (CLP) or sham operation (Sham). Pro-inflammatory cytokine (TNFα, IL-1β and IL-6) and anti-inflammatory cytokine (IL-4) gene expression in the liver and lung tissue were assessed by RT-PCR. The permeability of microvascular and water content in the lungs and liver were also examined.

RESULTS: Significant increase in TNFα, IL-1β and IL-6 gene expression was observed at 3 and 12 h after CLP both in the liver and lungs (P < 0.01).The level of IL-4 gene expression was not changed after CLP in the lungs, but increased at 12 h after CLP (P < 0.01) in the liver tissue. Both the liver and lungs showed a significant increase in microcirculatory permeability at 12 h after CLP(P < 0.01), and the increase in the lungs was higher than that in the liver. The water mass fractions in the liver (P < 0.05) and lungs (P < 0.01) were increased after CLP, and the increase in the lungs happened earlier and more severely than that in the liver.

CONCLUSION: The inflammatory response in the liver and lungs was different during sepsis. At the early stage of sepsis, pro-inflammatory reaction dominates both in the liver and lungs. But at the later stage of sepsis, induction of compensatory anti-inflammatory response was seen in the liver but not in the lungs. This difference in situ activity may contribute to the different vulnerability of organ damage during sepsis. The strategy of systemic administration of anti-inflammatory drugs to sepsis should be reconsidered.

Circulating inflammatory mediators in patients with fever: predicting bloodstream infection

The systemic host response to microbial infection involves clinical signs and symptoms of infection, including fever and elevated white blood cell (WBC) counts. In addition, inflammatory mediators are released, including activated complement product C3a, interleukin 6 (IL-6), and the acute-phase reactant secretory phospholipase A(2) (sPLA(2)). To compare the value of the latter with the former in predicting (the degree of) microbial infection at the bedside, we determined clinical variables and took blood samples daily for 3 consecutive days in 300 patients with a new fever (>38.0 degrees C rectally or >38.3 degrees C axillary). Microbiological culture results for 7 days after inclusion were collected. Patients were divided into clinical and microbial categories: those without and with a clinical focus of infection and those with negative cultures, with positive local cultures or specific stains for fungal (n = 13) or tuberculous infections (n = 1), and with positive blood cultures, including one patient with malaria parasitemia. The area under the curve (AUC) of the receiver operating characteristic (ROC) for prediction of positive cultures was 0.60 (P < 0.005) for peak temperature and 0.59 (P < 0.01) for peak WBC count, 0.60 (P < 0.005) for peak C3a, 0.63 (P < 0.001) for peak IL-6, and 0.61 (P < 0.001) for peak sPLA(2). The AUC under the ROC curve for prediction of positive blood cultures was 0.68 (P < 0.001) for peak temperature and 0.56 for peak WBC count (P < 0.05). The AUC for peak C3a was 0.69, that for peak IL-6 was 0.70, and that for sPLA(2) was 0.67 (for all, P < 0.001). The degree of microbial invasion is thus a major determinant of the clinical and inflammatory host response in patients with fever. Moreover, circulating inflammatory mediators such as C3a and IL-6 may help to predict positive blood cultures, together with clinical signs and symptoms of the host response to microbial infection, even before culture results are available. This may help in the designing of entry criteria for therapeutic intervention studies.

Interleukin 6 and C-reactive protein levels in patients with acute allergic reactions: an emergency department-based study

BACKGROUND

Elevations of interleukin 6 (IL-6) have been described in drug-induced anaphylaxis. Although IL-6 is well known to stimulate an acute phase response, profiling acute phase protein levels, such as C-reactive protein (CRP), has, to our knowledge, never been performed in patients with acute allergic reactions.

OBJECTIVE

To examine the pattern of IL-6 and CRP levels in patients with acute allergic reactions and to relate these to relevant clinical and laboratory parameters.

METHODS

Plasma CRP and serum IL-6 levels were determined in 85 adult emergency department patients. These patients had been previously studied with questionnaires, physical examinations, and histamine/tryptase levels. Clinical and historical features were related to CRP and IL-6 levels. CRP and IL-6 levels were also examined for relationships with histamine and tryptase levels.

RESULTS

CRP and IL-6 levels were significantly correlated with one another in the study patients (Spearman p = 0.36, P = 0.0008). Similar to histamine levels, IL-6 levels were significantly correlated with the extent of erythema manifested by the study patients. The extent of erythema was independently predicted by both IL-6 and histamine levels. Histamine levels were negatively correlated with CRP levels (Spearman p = -0.32, P = 0.003). Unlike histamine levels, IL-6 and CRP did not show significant relationships with the extent or presence of urticaria/angioedema or the presence of wheezing. IL-6 levels were correlated with the duration of symptoms before serologic sampling. An inverse correlation was observed between IL-6 levels and mean arterial blood pressure. Multivariate modeling showed significant independent effects from mean arterial pressure, duration of symptoms, erythema extent, and age in predicting IL-6 levels. Tryptase levels were higher in patients whose IL-6 levels were >20 pg/mL.

CONCLUSIONS

CRP and IL-6 levels are not simple surrogate markers for histamine or tryptase release by mast cells or basophils in acute allergic reactions. Increasing IL-6 levels relate to greater erythema extent, lower mean arterial blood pressure, and a longer duration of symptoms. It would be interesting to speculate that CRP and IL-6 increases characterize a late-phase response in immediate hypersensitivity reactions. In this perspective, the inverse relationship between CRP and histamine levels could be explained. As histamine levels are waning, CRP levels are increasing. Timed studies for histamine and CRP/IL-6 levels in allergic reactions are necessary to confirm this hypothesis.

Is nitric oxide overproduction the target of choice for the management of septic shock?

Sepsis is a heterogeneous class of syndromes caused by a systemic inflammatory response to infection. Septic shock, a severe form of sepsis, is associated with the development of progressive damage in multiple organs, and is a leading cause of patient mortality in intensive care units. Despite important advances in understanding its pathophysiology, therapy remains largely symptomatic and supportive. A decade ago, the overproduction of nitric oxide (NO) had been discovered as a potentially important event in this condition. As a result, great hopes arose that the pharmacological inhibition of NO synthesis could be developed into an efficient, mechanism-based therapeutic approach. Since then, an extraordinary effort by the scientific community has brought a deeper insight regarding the feasibility of this goal. Here we present in summary form the present state of knowledge of the biological chemistry and physiology of NO. We then proceed to a systematic review of experimental and clinical data, indicating an up-regulation of NO production in septic shock; information on the role of NO in septic shock, as provided by experiments in transgenic mice that lack the ability to up-regulate NO production; effects of pharmacological inhibitors of NO production in various experimental models of septic shock; and relevant clinical experience. The accrued evidence suggests that the contribution of NO to the pathophysiology of septic shock is highly heterogeneous and, therefore, difficult to target therapeutically without appropriate monitoring tools, which do not exist at present.

Interleukin-6 and C-reactive protein serum levels in sepsis-related fatalities during the early postmortem period

Postmortem interleukin-6 (IL-6) and C-reactive protein (CRP) serum levels were investigated prospectively in sepsis-related fatalities and non-septic fatalities by using a linear regression model. At least three blood samples were collected between 0.3 and 139 h postmortem from sepsis-related fatalities (n=8) and non-septic fatalities (n=16). In addition, one antemortem blood sample was collected shortly before death from the septic patients. Antemortem and postmortem IL-6 and CRP levels were highly elevated in all individuals included in the sepsis group. An excessive postmortem increase of IL-6 serum levels associated with progressive time after death was observed in five out of the eight septic patients. Both, IL-6 and CRP serum concentrations seem to be suitable biochemical postmortem markers of sepsis. The determination of IL-6 serum levels above 1500 pg/ml in peripheral venous blood obtained in the early postmortem interval can be considered as a diagnostic hint towards an underlying septic condition. A more precise postmortem discrimination between sepsis and non-septic underlying causes of death is provided by the postmortem measurement of serum CRP in peripheral venous blood: on condition that at least two postmortem CRP values have been determined at different time points postmortem, the CRP level of a deceased at the time of death can be calculated by using linear regression analysis. When assessing postmortem IL-6 and CRP concentrations as biochemical postmortem markers of sepsis, various clinical conditions, such as a preceding trauma or burn injury going along with elevated IL-6 and/or CRP levels prior to death as a result of the systemic inflammatory response syndrome (SIRS) should be taken into consideration, thus adding relevant information for the practical interpretation of the results.