Nuclear factor-kappaB activation in peripheral blood mononuclear cells in children with sepsis. Crit Care Med. 2007;35:2395-2401. [PMID: 17944030 DOI: 10.1097/01.ccm.0000284502.38701.e6]

Role of Nuclear Factor-Kappa B Activation and Inflammatory Biomarkers in Critically Ill Children

Mortality prediction is important for cautious monitoring and optimal management of critically ill children. The serum cytokine levels are elevated early in critical illness before the physiological parameters are deranged. This cross-sectional descriptive study included the critically ill children admitted in intensive care unit. Serial serum levels of IL-6, NF-κB and PELOD 2 scoring were measured and compared in 45 children (40 survivors, 5 non-survivors). The median IL-6 levels at 24 h and 72 h were significantly high in non-survivors when compared to survivors [median (IQR) = 1122 (1305) pg/ml vs. 564.39 (153) pg/ml and 1263 (626) pg/ml vs. 82 (191) pg/ml respectively; p <0.0001)]. There was an increasing trend of IL-6 in non-survivors when compared to the survivors. The NF-κB values were comparable. The IL-6 levels correlated well with the illness severity. IL-6 had superior prognostic value compared with NF-κB in predicting mortality.

Sepsis Patients Display a Reduced Capacity to Activate Nuclear Factor-κB in Multiple Cell Types

OBJECTIVES

Sepsis is a complex clinical condition associated with high morbidity and mortality. A distinctive feature of sepsis is the reduced capacity of leukocytes to release proinflammatory cytokines in response to ex vivo stimulation. Cellular signaling events leading to immunosuppression in sepsis are not well defined. We investigated cell-specific signaling events underlying the immunosuppressed phenotype in sepsis.

DESIGN

Ex vivo study.

SETTING

ICU of an academic hospital.

PATIENTS

Nineteen patients with sepsis and 19 age-matched healthy controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The phosphorylation state of p38 mitogen activated protein kinase and nuclear factor kappa-light-chain-enhancer of activated B cells were determined in ex vivo stimulated CD4 T cells, CD8 T cells, B cells, monocytes, and neutrophils. Messenger RNA expression levels of p38 mitogen activated protein kinase and nuclear factor kappa-light-chain-enhancer of activated B cells and negative regulators tumor necrosis factor-α-induced protein 3 (A20) and mitogen activated protein kinase phosphatase-1 were determined in neutrophils and peripheral blood mononuclear cells. Upon ex vivo stimulation, monocytes of sepsis patients were less capable in phosphorylating nuclear factor kappa-light-chain-enhancer of activated B cells. Sepsis was also associated with reduced phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells in stimulated B cells, CD4 and CD8 T cells. Messenger RNA expression levels of nuclear factor kappa-light-chain-enhancer of activated B cells and A20 were diminished in peripheral blood mononuclear cells of sepsis patients, whereas p38 mitogen activated protein kinase messenger RNA was up-regulated. In neutrophils of sepsis patients, mitogen activated protein kinase phosphatase-1 messenger RNA levels were down-regulated.

CONCLUSIONS

Sepsis-induced immunosuppression associates with a defect in the capacity to phosphorylate nuclear factor kappa-light-chain-enhancer of activated B cells in lymphoid cells and monocytes.

Oxidative stress biomarkers in pediatric sepsis: a prospective observational pilot study

OBJECTIVES

Oxidative stress is known to participate in the progression of sepsis. Definite data regarding the behavior of oxidative stress biomarkers in pediatric sepsis is still lacking. This study hypothesized that oxidative stress occurs in pediatric sepsis and that the magnitude of the redox derangement is associated with worse clinical progression.

METHODS

Forty-two previously healthy pediatric patients with sepsis and a group of control subjects were included. Oxidative stress and inflammatory activity biomarkers were determined in blood samples. Patients were prospectively followed until their discharge or death.

RESULTS

Patients with non-severe and severe sepsis showed higher levels of plasmatic antioxidant capacity, lower erythrocyte thiol index, lower superoxide dismutase and catalase activities, higher glutathione peroxidase activity, and higher plasmatic F₂-isoprostanes concentration than controls. Patients with severe sepsis had higher NF-kappaB activation than those with non-severe sepsis. Although we observed changes in some biomarkers in patients with worse clinical evolution, the explored biomarkers did not correlate with clinical estimators of outcome.

DISCUSSION

Oxidative stress occurs in pediatric sepsis, resulting in oxidative damage. The explored biomarkers are not useful as outcome predictors in the studied population. The behavior of these biomarkers still needs to be addressed in broader groups of pediatric patients with sepsis.

Association of REL polymorphisms and outcome of patients with septic shock

Background

cRel, a subunit of NF-κB, is implicated in the inflammatory response observed in autoimmune disease. Hence, knocked-out mice for cRel had a significantly higher mortality, providing new and important functions of cRel in the physiopathology of septic shock. Whether genetic variants in the human REL gene are associated with severity of septic shock is unknown.

Methods

We genotyped a population of 1040 ICU patients with septic shock and 855 ICU controls for two known polymorphisms of REL; REL rs842647 and REL rs13031237. Outcome of patients according to the presence of REL variant alleles was compared.

Results

The distribution of REL variant alleles was not significantly different between patients and controls. Among the septic shock group, REL rs13031237*T minor allele was not associated with worse outcome. In contrast, REL rs842647*G minor allele was significantly associated with more multi-organ failure and early death [OR 1.4; 95 % CI (1.02–1.8)].

Conclusion

In a large ICU population, we report a significant clinical association between a variation in the human REL gene and severity and mortality of septic shock, suggesting for the first time a new insight into the role of cRel in response to infection in humans.

Metabolic theory of septic shock

Septic shock is a life threatening condition that can develop subsequent to infection. Mortality can reach as high as 80% with over 150000 deaths yearly in the United States alone. Septic shock causes progressive failure of vital homeostatic mechanisms culminating in immunosuppression, coagulopathy and microvascular dysfunction which can lead to refractory hypotension, organ failure and death. The hypermetabolic response that accompanies a systemic inflammatory reaction places high demands upon stored nutritional resources. A crucial element that can become depleted early during the progression to septic shock is glutathione. Glutathione is chiefly responsible for supplying reducing equivalents to neutralize hydrogen peroxide, a toxic oxidizing agent that is produced during normal metabolism. Without glutathione, hydrogen peroxide can rise to toxic levels in tissues and blood where it can cause severe oxidative injury to organs and to the microvasculature. Continued exposure can result in microvascular dysfunction, capillary leakage and septic shock. It is the aim of this paper to present evidence that elevated systemic levels of hydrogen peroxide are present in septic shock victims and that it significantly contributes to the development and progression of this frequently lethal condition.

Septic encephalopathy: when cytokines interact with acetylcholine in the brain

Sepsis-associated encephalopathy (SAE) is a brain dysfunction that occurs secondary to infection in the body, characterized by alteration of consciousness, ranging from delirium to coma, seizure or focal neurological signs. SAE involves a number of mechanisms, including neuroinflammation, in which the interaction between cytokines and acetylcholine results in neuronal loss and alterations in cholinergic signaling. Moreover, the interaction also occurs in the periphery, accelerating a type of immunosuppressive state. Although its diagnosis is not specific in biochemistry and imaging tests, it could potentiate severe outcomes, including increased mortality, cognitive decline, progressive immunosuppression, cholinergic anti-inflammatory deficiency, and even metabolic and hydroelectrolyte imbalance. Therefore, the bilateral communication between SAE and the multiple peripheral organs and especially the immune system should be emphasized in sepsis management.

Inflammation, myocardial dysfunction, and mortality in children with septic shock: an observational study

We aimed to investigate whether nuclear factor kappa-B activation, as evaluated by gene expression of its inhibitor (I-κBα) and cytokine serum levels, was associated with myocardial dysfunction and mortality in children with septic shock. Twenty children with septic shock were prospectively enrolled and grouped according to ejection fraction (EF) <45% (group 1) or EF ≥45% (group 2) on the first day after admission to the pediatric intensive care unit. No interventions were made. In the first day, patients from group 1 (n = 6) exhibited significantly greater tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-10 plasma levels. However, I-κBα gene expression was not different in both groups. Mortality and number of complications were significantly greater in group 1. Patients who died had greater plasma concentrations of TNF-α. In conclusion, TNF-α and IL-10 are involved in myocardial dysfunction accompanying septic shock in children, and TNF-α is associated with mortality.

Circulating monocytes are not the major source of plasma cytokines in patients with sepsis

In sepsis, large quantities of inflammatory cytokines are released into the bloodstream. The cellular source of these cytokines is unclear, and we have here investigated to what extent circulating cells in blood contributed to this production. We used the enzyme-linked immunospot technique to study the spontaneous as well as the lipopolysaccharide (LPS)-induced secretion of the proinflammatory cytokines interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), granulocyte-macrophage colony-stimulating factor, IL-1β, IL-12p40, and the anti-inflammatory cytokine IL-10 from whole-blood cells. The study comprised 32 septic patients (24 with septic shock) and 30 healthy controls. Despite significantly increased plasma cytokine levels in the septic patients, the number of spontaneous cytokine-secreting cells was small or nonexistent and did not differ between the two groups. Lipopolysaccharide stimulation of cells from the same samples triggered substantially increased numbers of cytokine-producing cells in both patients and controls. However, although the numbers of IL-6- and tumor necrosis factor α-secreting monocytes were very similar in both groups, significantly fewer IL-1β-, IL-10-, IL-12p40-, and granulocyte-macrophage colony-stimulating factor-secreting monocytes were seen in samples from septic patients as compared with healthy controls. The reduced number of cytokine-secreting cells in response to LPS stimulation correlated with disease severity, as expressed by Sequential Organ Failure Assessment score and the stage of sepsis. In summary, circulating leukocytes did not appear to be responsible for the increased plasma levels of cytokines observed in sepsis. A selective sepsis-induced downregulation of cytokine secretion in response to LPS underscores the complexity of cytokine regulation in sepsis.

Mononuclear cell subpopulations in CSF and blood of children with bacterial meningitis

OBJECTIVES

To elucidate mononuclear cell subsets of the cerebrospinal fluid (CSF) in order to investigate the pathogenesis of bacterial meningitis (BM).

METHODS

Mononuclear cell and lymphocyte subsets in CSF and peripheral blood from 10 children with acute-stage BM before treatment on the same day were measured by flow cytometry. The control subjects for the subsets of peripheral blood were 15 healthy children.

RESULTS

The percentages of CD14+ monocytes/macrophages (median: 56.5%), activated CD14+CD16+ monocytes/macrophages (20.9%), and CD14+CD16+ cells among total CD14+ cells (37.9%) in the CSF were significantly higher than those in the blood of children with BM (p<0.01, p<0.01, and p<0.05, respectively), which were significantly higher than those of the controls (p<0.001, p<0.001, p<0.05, respectively). The percentages of CD3+ (77.3%), CD4+ (45.2%), and CD8+ T cells (32.6%) in the CSF were significantly higher than those in the blood of affected children (p<0.01, p<0.01, and p<0.05, respectively). The percentages of CD3+, CD4+, and CD8+ T cells in the blood of children with BM were significantly lower than those of controls (all p<0.001). The percentages of CD20+ B cells (6.9%) in the CSF were significantly lower than those in the blood of affected children (p<0.01), which were significantly higher than those of controls (p<0.001).

CONCLUSION

The percentages of monocytes/macrophages and T cells in CSF were higher than those in blood in children with BM.

Time lag between the increase of IL-6 with fever and NF-kappaB activation in the peripheral blood in inflammatory myofibroblastic tumor

We describe a case of inflammatory myofibroblastic tumor (IMT) that occurred in the retroperitoneum. The patient manifested systemic symptoms, such as intermittent fever, anemia, thrombocytosis, and hypergammaglobulinemia. In order to elucidate the mechanism of intermittent fever in IMT, we analyzed nuclear factor-kappa B (NF-kappaB) activation in peripheral blood mononuclear cells (PBMCs) using flow cytometry, and serum cytokine levels. NF-kappaB activation was observed in the peripheral blood T cells and monocytes/macrophages. Among the measured cytokines, only interleukin (IL)-6 levels were elevated. IL-6 levels during pyrexia in the afternoon were higher than those during apyrexia in the morning. In contrast to IL-6, NF-kappaB activation in PBMCs was lower during pyrexia than during apyrexia; this is considered to be because the activation is subject to negative feedback. The time lag between the increase of IL-6 in the serum and NF-kappaB activation in the PBMCs at the onset of intermittent fever in IMT may provide further insight into the role of cytokines and NF-kappaB activation in febrile inflammatory diseases.

Cytokine levels in sputum of patients with tracheostomy and profound multiple disabilities

BACKGROUND

Airway immunopathogenesis is unclear in patients with profound multiple disabilities (PMD) who undergo tracheostomy.

METHODS

The levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, IL-8, IL-10, and IL-12p70 cytokines were determined in sputum of 28 patients with PMD who underwent tracheostomy and in 14 healthy subjects, using a cytometric bead array.

RESULTS

The concentrations of IL-1beta, IL-6 and IL-8 in the patients were significantly higher than those in controls (p < 0.001). IL-6, and IL-8 levels in eight PMD patients in the febrile period were significantly higher than those in the afebrile period (p < 0.01 and p < 0.05, respectively). Serum CRP levels were slightly elevated in 12 of the 28 patients (43%) in the afebrile period, but there were no significant differences in the level of any cytokine between patients with normal and elevated serum CRP.

CONCLUSION

PMD patients with tracheostomy have chronic airway inflammation.