Predictive value of nuclear factor kappaB activity and plasma cytokine levels in patients with sepsis

Artesunate Protects Against Sepsis-Induced Lung Injury Via Heme Oxygenase-1 Modulation

Artesunate, a derivative of artemisinin, has anti-inflammatory properties and exerts protective roles in sepsis. Heme oxygense-1 (HO-1) inhibits the inflammatory response through reduction of proinflammatory cytokines and leukocyte influx into tissues. The present study investigated the effects of artesunate on HO-1 and septic lung injury. Cecal ligation and puncture (CLP) was employed to induce septic lung injury. Mice pretreated with artesunate (AS) (15 mg/kg) exhibited decreased sepsis-induced mortality and lung injury and alleviated lung pathological changes and neutrophil infiltration. In addition, AS lowered the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the serum and bronchoalveolar lavage fluid (BALF) and inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) expression and NF-κB activation in lung tissue. In addition, AS enhanced NF-E2-related factor-2 (Nrf2) activation and HO-1 expression and enzymatic activity in lung tissue. However, the protective effects of AS on sepsis-induced lung injury were eliminated by ZnPP IX, an HO-1 competitive inhibitor. Therefore, AS plays protective roles in septic lung injury related to the upregulation of HO-1. These findings suggest an effective and applicable treatment to sepsis-induced lung injury and provide new insights into the molecular mechanisms and actions of AS.

The synthetic antimicrobial peptide 19-2.5 attenuates septic cardiomyopathy and prevents down-regulation of SERCA2 in polymicrobial sepsis

An impairment of cardiac function is a key feature of the cardiovascular failure associated with sepsis. Although there is some evidence that suppression of sarcoplasmic reticulum Ca²⁺-ATP-ase (SERCA2) contributes to septic cardiomyopathy, it is not known whether prevention of the down-regulation of SERCA2 improves outcome in sepsis. Thus, we investigated whether the administration of the synthetic antimicrobial peptide Pep2.5 may attenuate the cardiac dysfunction in murine polymicrobial sepsis through regulating SERCA2 expression. We show here for the first time that the infusion of Pep2.5 reduces the impaired systolic and diastolic contractility and improves the survival time in polymicrobial sepsis. Preservation of cardiac function in sepsis by Pep2.5 is associated with prevention of the activation of NF-κB and activation of the Akt/eNOS survival pathways. Most notably, Pep2.5 prevented the down-regulation of SERCA2 expression in a) murine heart samples obtained from mice with sepsis and b) in cardiomyocytes exposed to serum from septic shock patients. Thus, we speculate that Pep2.5 may be able to prevent down-regulation of cardiac SERCA2 expression in patients with sepsis, which, in turn, may improve cardiac function and outcome in these patients.

Protective effects of isohelenin, an inhibitor of nuclear factor κB, in endotoxic shock in rats

Recent in vitro studies have shown that isohelenin, a sesquiterpene lactone, inhibits the NF-κB pathway. This study examines the effect of isoheleninin endotoxic shock induced by administration of Escherichia coli endotoxini n male Wistar rats. A group of rats received isohelenin (2 mg/kg intraperitoneally)15 min before endotoxin. In vehicle-treated rats, administration of endotoxin caused severe hypotension, which was associated with a marked hyporeactivity to norepinephrine and acetylcholine in ex vivo aortas. Elevated levels of plasma nitrate/nitrite, metabolites of nitric oxide (NO), were also found. These inflammatory events were preceded by cytosolic degradation of inhibitor-κBα (IκBα) and activation of nuclear factor-κB (NF-κB) in the lung within 15 min of endotoxin administration. Treatment with isohelenin resulted in hemodynamicimprovement and reduced plasma levels of NO metabolites. Nuclear translocation of NF-κB was inhibited by isohelenin treatment in the lung, whereas degradation of IκBα was unchanged. In a separate set of experiments, treatment with isohelenin significantly improved survival in mice challenged with endotoxin. We conclude that isohelenin exerts beneficial therapeutic effects during endotoxic shock through inhibition of NF-κB.

Metabolites Associated With Malnutrition in the Intensive Care Unit Are Also Associated With 28-Day Mortality

BACKGROUND

We hypothesized that metabolic profiles would differ in critically ill patients with malnutrition relative to those without.

MATERIALS AND METHODS

We performed a prospective cohort study on 85 adult patients with systemic inflammatory response syndrome or sepsis admitted to a 20-bed medical intensive care unit (ICU) in Boston. We generated metabolomic profiles using gas and liquid chromatography and mass spectroscopy. We followed this by logistic regression and partial least squares discriminant analysis to identify individual metabolites that were significant. We then interrogated the entire metabolomics profile using metabolite set enrichment analysis and network model construction of chemical-protein target interactions to identify groups of metabolites and pathways that were differentiates in patients with and without malnutrition.

RESULTS

Of the cohort, 38% were malnourished at admission to the ICU. Metabolomic profiles differed in critically ill patients with malnutrition relative to those without. Ten metabolites were significantly associated with malnutrition ( P < .05). A parsimonious model of 5 metabolites effectively differentiated patients with malnutrition (AUC = 0.76), including pyroglutamine and hypoxanthine. Using pathway enrichment analysis, we identified a critical role of glutathione and purine metabolism in predicting nutrition. Nutrition status was associated with 28-day mortality, even after adjustment for known phenotypic variables associated with ICU mortality. Importantly, 7 metabolites associated with nutrition status were also associated with 28-day mortality.

CONCLUSION

Malnutrition is associated with differential metabolic profiles early in critical illness. Common to all of our metabolome analyses, glutathione and purine metabolism, which play principal roles in cellular redox regulation and accelerated tissue adenosine triphosphate degradation, respectively, were significantly altered with malnutrition.

Modifications to the composition of the hyphal outer layer of Aspergillus fumigatus modulates HUVEC proteins related to inflammatory and stress responses

Aspergillus fumigatus, the main etiologic agent causing invasive aspergillosis, can induce an inflammatory response and a prothrombotic phenotype upon contact with human umbilical vein endothelial cells (HUVECs). However, the fungal molecules involved in this endothelial response remain unknown. A. fumigatus hyphae produce an extracellular matrix composed of galactomannan, galactosaminogalactan and α-(1,3)-glucan. In this study, we investigated the consequences of UGM1 gene deletion in A. fumigatus, which produces a mutant with increased galactosaminogalactan production. The ∆ugm1 mutant exhibited an HUVEC-hyperadhesive phenotype and induced increased endothelial TNF-α secretion and tissue factor mRNA overexpression in this "semi-professional" immune host cell. Using a shotgun proteomics approach, we show that the A. fumigatus ∆ugm1 strain can modulate the levels of proteins in important endothelial pathways related to the inflammatory response mediated by TNF-α and to stress response pathways. Furthermore, a purified galactosaminogalactan fraction was also able to induce TNF-α secretion and the coincident HUVEC pathways regulated by the ∆ugm1 mutant, which overexpresses this component, as demonstrated by fluorescence microscopy. This work contributes new data regarding endothelial mechanisms in response to A. fumigatus infection.

SIGNIFICANCE

Invasive aspergillosis is the main opportunistic fungal infection described in neutropenic hematologic patients. One important clinical aspect of this invasive fungal infection is vascular thrombosis, which could be related, at least in part, to the activation of endothelial cells, as shown in previous reports from our group. It is known that direct contact between the A. fumigatus hyphal cell wall and the HUVEC cell surface is necessary to induce an endothelial prothrombotic phenotype and secretion of pro-inflammatory cytokines, though the cell surface components of this angioinvasive fungus that trigger this endothelial response are unknown. The present work employs a discovery-driven proteomics approach to reveal the role of one important cell wall polysaccharide of A. fumigatus, galactosaminogalactan, in the HUVEC interaction and the consequent mechanisms of endothelial activation. This is the first report of the overall panel of proteins related to the HUVEC response to a specific and purified cell wall component of the angioinvasive fungus A. fumigatus.

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.

The Expression of Nuclear Transcription Factor Kappa B (NF-κB) in the Case of Critically Ill Polytrauma Patients with Sepsis and Its Interactions with microRNAs

Critical polytrauma patients present a series of pathophysiological disturbances, biochemical and molecular dysfunction, which comprise to be the major cause of intensive care unit admission. In regard to molecular damage, there exists a series of factors, which all together contribute to the aggravation of the clinical status leading to increased mortality rate in these patients. One of the most important biochemical factors involved is the nuclear transcription factor B (NF-κB). Impaired NF-κB functioning is reflected on the clinical status of the patient through increased production of pro-inflammatory molecule, leading to multiple organ dysfunction syndrome. In addition to this, through microRNAs interactions, various pathophysiological as well as biochemical disturbances are produced, which altogether further reduce the patient's survival rate. In this paper, we would like to present the modifications seen in the expression of NF-κB in critically polytraumatized patients with sepsis. In additions to this, we would like to discuss the correlation between the microRNAs and its further implications in clinical status of these patients.

C1P Attenuates Lipopolysaccharide-Induced Acute Lung Injury by Preventing NF-κB Activation in Neutrophils

Recently, ceramide-1-phosphate (C1P) has been shown to modulate acute inflammatory events. Acute lung injury (Arnalich et al. 2000. Infect. Immun. 68: 1942-1945) is characterized by rapid alveolar injury, lung inflammation, induced cytokine production, neutrophil accumulation, and vascular leakage leading to lung edema. The aim of this study was to investigate the role of C1P during LPS-induced acute lung injury in mice. To evaluate the effect of C1P, we used a prophylactic and therapeutic LPS-induced ALI model in C57BL/6 male mice. Our studies revealed that intrapulmonary application of C1P before (prophylactic) or 24 h after (therapeutic) LPS instillation decreased neutrophil trafficking to the lung, proinflammatory cytokine levels in bronchoalveolar lavage, and alveolar capillary leakage. Mechanistically, C1P inhibited the LPS-triggered NF-κB levels in lung tissue in vivo. In addition, ex vivo experiments revealed that C1P also attenuates LPS-induced NF-κB phosphorylation and IL-8 production in human neutrophils. These results indicate C1P playing a role in dampening LPS-induced acute lung inflammation and suggest that C1P could be a valuable candidate for treatment of ALI.

Carbon Monoxide Inhibits Tenascin-C Mediated Inflammation via IL-10 Expression in a Septic Mouse Model

Tenascin-C (TN-C), an extracellular matrix (ECM) glycoprotein, is specifically induced upon tissue injury and infection and during septic conditions. Carbon monoxide (CO) gas is known to exert various anti-inflammatory effects in various inflammatory diseases. However, the mechanisms underlying the effect of CO on TN-C-mediated inflammation are unknown. In the present study, we found that treatment with LPS significantly enhanced TN-C expression in macrophages. CO gas, or treatment with the CO-donor compound, CORM-2, dramatically reduced LPS-induced expression of TN-C and proinflammatory cytokines while significantly increased the expression of IL-10. Treatment with TN-C siRNA significantly suppressed the effects of LPS on proinflammatory cytokines production. TN-C siRNA did not affect the CORM-2-dependent increase of IL-10 expression. In cells transfected with IL-10 siRNA, CORM-2 had no effect on the LPS-induced expression of TN-C and its downstream cytokines. These data suggest that IL-10 mediates the inhibitory effect of CO on TN-C and the downstream production of proinflammatory cytokines. Additionally, administration of CORM-2 dramatically reduced LPS-induced TN-C and proinflammatory cytokines production while expression of IL-10 was significantly increased. In conclusion, CO regulated IL-10 expression and thus inhibited TN-C-mediated inflammation in vitro and in vivo.

Saikosaponin A protects against experimental sepsis via inhibition of NOD2-mediated NF-κB activation

The excessive production of inflammatory cytokines during invasive infection primarily mediates the pathophysiology of sepsis. To improve the survival of septic patients, many selective or mediator-specific anti-inflammatory agents have been developed. Saikosaponin A (SsA), a triterpenoid saponin isolated from Radix Bupleuri, inhibits the production of proinflammatory mediators in several cell types and protects against CCl₄-induced liver injury in rats. However, whether SsA treatment provides protective effects against sepsis remains unknown. The aim of the present study was to investigate the anti-inflammatory role of SsA in septic rats and the possible involvement of the nucleotide-binding oligomerization domain 2 (NOD2)/NF-κB signaling pathway in the regulation of inflammatory cytokine expression. Sixty male Wistar rats were randomly divided into six groups (10 rats per group): Sham surgery, cecal ligation and puncture (CLP), CLP plus SsA (1.0 mg/kg), CLP plus SsA (2.5 mg/kg), CLP plus SsA (5.0 mg/kg) and sham surgery plus SsA (2.5 mg/kg) groups. Rats in the SsA groups were intraperitoneally (i.p.) injected with different doses of SsA following the CLP surgery. Tissues from the ileum were harvested 8 h after CLP or sham surgery and the levels of inflammatory cytokines and NOD2 mRNA, and the activation of NF-κB were measured. The concentrations of the cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6, as well as the NOD2 mRNA expression levels and NF-κB activation in the intestinal tissues were significantly increased in the septic rats of the CLP group compared with those in the sham group. SsA administration effectively suppressed the increase in the levels of TNF-α and IL-6. Moreover, the upregulation of NOD2 mRNA expression and phospho-NF-κB p65 levels was significantly inhibited following the administration of SsA. SsA may exert a protective role in the septic process by suppressing TNF-α and IL-6 concentrations in the intestines of septic rats and these effects appear to be mediated, at least partly, via inhibition of the NOD2/NF-κB signaling pathway.

α-Lipoic acid prolongs survival and attenuates acute kidney injury in a rat model of sepsis

Acute kidney injury is a frequent and serious complication in patients with severe sepsis. α-Lipoic acid (ALA), a naturally occurring dithiol compound, has been shown to possess anti-inflammatory and anti-oxidative properties. In the present study we investigated whether ALA could attenuate acute kidney injury and improve survival in a rat model of sepsis. Rats were subjected to caecal ligation and puncture (CLP) to induce sepsis. α-Lipoic acid (200 mg/kg) was administered by oral gavage either immediately (early treatment) or 12 h after the surgical procedure (delayed treatment). Both early and delayed ALA treatment effectively prolonged survival, improved pathological damage in kidney tissues and reduced serum blood urea nitrogen and creatinine levels in CLP-induced septic rats. Furthermore, early treatment with ALA markedly inhibited the release of tumour necrosis factor-α, interleukin (IL)-6 and IL-1β into the serum and reduced mRNA and protein expression of inducible nitric oxide synthase and high mobility group box 1 in kidney tissues from CLP-induced rats. Finally, CLP-induced nuclear factor-κB activation in kidney tissues was significantly suppressed by early ALA treatment. Together, the results indicate that ALA is able to reduce mortality and attenuate acute kidney injury associated with sepsis, possibly by anti-inflammatory actions. α-Lipoic acid may be a promising novel agent for the treatment of conditions associated with septic shock.

Downregulation of adenine nucleotide translocator 1 exacerbates tumor necrosis factor-α-mediated cardiac inflammatory responses

Inflammation contributes significantly to cardiac dysfunction. Although the initial phase of inflammation is essential for repair and healing, excessive proinflammatory cytokines are detrimental to the heart. We found that adenine nucleotide translocator isoform-1 (ANT1) protein levels were significantly decreased in the inflamed heart of C57BL/6 mice following cecal ligation and puncture. To understand the molecular mechanisms involved, we performed small-interfering RNA-mediated knockdown of ANT1 and studied tumor necrosis factor-α (TNFα)-induced inflammatory responses in myocardium-derived H9c2 cells and cardiomyocytes. ANT1 knockdown significantly increased swollen mitochondria and mitochondrial reactive oxygen species, concomitant with increased TNFα-induced NF-κB reporter gene activity and interleukin-6 and TNFα expression. A mitochondrial-targeted antioxidant mito-TEMPO attenuated TNFα-induced mitochondrial reactive oxygen species, NF-κB reporter gene activity, and cytokine expression in ANT1 knockdown cells. Interestingly, TNFα or lipopolysaccharide (LPS) treatment significantly decreased ANT1 protein levels, suggesting a feed-forward regulation of proinflammatory cytokine expression activated by ANT1 downregulation. These data suggest that ANT1 downregulation contributes to cardiac inflammation post-cecal ligation and puncture. Preventing ANT1 downregulation could provide a novel molecular target to temper cardiac inflammation.

Betulinic acid attenuates lung injury by modulation of inflammatory cytokine response in experimentally-induced polymicrobial sepsis in mice

Sepsis commonly progresses to acute lung injury (ALI), an inflammatory lung disease with high morbidity and mortality. Septic ALI is characterized by excessive production of proinflammatory mediators. It remained refractory to present therapies and new therapies need to be developed to improve further clinical outcomes. Betulinic acid (BA), a pentacyclic lupane group triterpenoid has been shown to have anti-inflammatory activities in many studies. However, its therapeutic efficacy in polymicrobial septic ALI is yet unknown. Therefore, we investigated the effects of BA on septic ALI using cecal ligation and puncture (CLP) model in mice. Vehicle or BA (3, 10, and 30mg/kg) was administered intraperitoneally, 3 times (0, 24 and 48h) before CLP and CLP was done on 49(th)h of the study. Survival rate was observed till 120h post CLP. Lung tissues were collected for analysis by sacrificing mice 18h post CLP. BA at 10 and 30mg/kg dose significantly reduced sepsis-induced mortality and lung injury as implied by attenuated lung histopathological changes, decreased protein and neutrophils infiltration. BA also decreased lung NF-κB expression, cytokine, intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and matrix metalloproteinase-9 levels. These evidences suggest that, the protective effects of BA on lungs are associated with defending action against inflammatory response and BA could be a potential modulatory agent of inflammation in sepsis-induced ALI.

Exogenous recombinant adiponectin improves survival in experimental abdominal sepsis

BACKGROUND

Adiponectin, which has anti-inflammatory features, is an important substance in several metabolic mechanisms.

AIMS

The aim of this study is to evauate the effects of exogenous intraperitoneal administration of adiponectin on the survival, intrabdominal adhesion and inflammatory cytokine levels in an experimental sepsis model.

STUDY DESIGN

Animal experimentation.

METHODS

Ninety rats were divided into a control group, adiponectin group and sham group. A cecal puncture abdominal sepsis model was performed in the adiponectin and control groups. Every three hours, exogenous adiponectin was administrated to the adiponectin group. At the 3(rd) and 24(th) hours, 10 rats were sacrified in each group in order to measure plasma tumor necrosis factor-α (TNF-α), interleukin (IL) 10, soluble intracellular adhesion molecule (ICAM)-1, IL-6 and macrophage inhibitory factor levels, and the activity of nuclear factor (NF)-kB. The remaining rats were followed for survival.

RESULTS

The plasma levels of TNF-α, soluable ICAM-1, IL-6, and macrophage inhibitory factor were significantly higher in the control group than in the adiponectin and sham group (p<0.05). The increase in inflammatory cytokines with time was more prominent in the control group. The activity of NF-kB in the control group was higher than in the adiponectin group (p<0.05). The survival rate of the adiponectin group was higher than in the control group.

CONCLUSION

Administration of exogenous adiponectin to the peritoneum in abdominal sepsis increased survival and decreased intrabdominal adhesions by decreasing the inflammatory response.

Usefulness of α7 nicotinic receptor messenger RNA levels in peripheral blood mononuclear cells as a marker for cholinergic antiinflammatory pathway activity in septic patients: results of a pilot study

BACKGROUND

Stimulation of the vagus nerve in the so-called cholinergic antiinflammatory pathway (CAP) attenuates systemic inflammation, improving survival in animal sepsis models via α7 nicotinic acetylcholine receptors on immunocompetent cells. Because the relevance of this regulatory pathway is unknown in human sepsis, this pilot study assessed whether the α7 gene expression level in septic patients' peripheral blood mononuclear cells (PBMC) might be used to assess CAP activity and clinical outcome.

METHODS

The PBMCs α7 messenger RNA levels were determined by real-time quantitative reverse-transcription polymerase chain reaction in 33 controls and 33 patients at enrollment and after their hospital discharge. Data were analyzed to find significant associations between α7 level, vagally mediated heart rate variability as an indirect reflection of CAP activity, serum concentrations of different inflammation markers, and clinical course.

RESULTS

Septic patients' α7 levels were significantly increased and returned to control values after recovery. These α7 levels correlated directly with the vagal heart input and inversely with the magnitude of the patient's inflammatory state, disease severity, and clinical outcome.

CONCLUSIONS

This study reveals that the PBMC α7 gene expression level is a clinically relevant marker for CAP activity in sepsis: the higher the α7 expression, the better the inflammation control and the prognosis.

Cholecystokinin inhibits inducible nitric oxide synthase expression by lipopolysaccharide-stimulated peritoneal macrophages

Cholecystokinin (CCK) was first described as a gastrointestinal hormone. However, apart from its gastrointestinal effects, studies have described that CCK also plays immunoregulatory roles. Taking in account the involvement of inducible nitric oxide synthase- (iNOS-) derived NO in the sepsis context, the present study was undertaken to investigate the role of CCK on iNOS expression in LPS-activated peritoneal macrophages. Our results revealed that CCK reduces NO production and attenuates the iNOS mRNA expression and protein formation. Furthermore, CCK inhibited the nuclear factor- (NF-) κB pathway reducing IκBα degradation and minor p65-dependent translocation to the nucleus. Moreover, CCK restored the intracellular cAMP content activating the protein kinase A (PKA) pathway, which resulted in a negative modulatory role on iNOS expression. In peritoneal macrophages, the CCK-1R expression, but not CCK-2R, was predominant and upregulated by LPS. The pharmacological studies confirmed that CCK-1R subtype is the major receptor responsible for the biological effects of CCK. These data suggest an anti-inflammatory role for the peptide CCK in modulating iNOS-derived NO synthesis, possibly controlling the macrophage activation through NF-κB, cAMP-PKA, and CCK-1R pathways. Based on these findings, CCK could be used as an adjuvant agent to modulate the inflammatory response and prevent systemic complications commonly found during sepsis.

Effect of the Toll-like receptor 4 antagonist eritoran on retinochoroidal inflammatory damage in a rat model of endotoxin-induced inflammation

Purpose. We investigated the effect of eritoran, a Toll-like receptor 4 antagonist, on retinochoroidal inflammatory damage in an endotoxin-induced inflammatory rat model. Methods. Endotoxin-induced inflammatory model was obtained by intraperitoneal injection of 1.5 mg/kg lipopolysaccharide (LPS). Group 1 had control rats; in groups 2-3 LPS and 0.5 mg/kg sterile saline were injected; and in groups 4-5 LPS and 0.5 mg/kg eritoran were injected. Blood samples were taken and eyes were enucleated after 12 hours (h) (groups 2 and 4) or 24 hours (Groups 3 and 5). Tumor necrosis factor-α (TNF-α) and malondialdehyde (MDA) levels in the serum and retinochoroidal tissue and nuclear factor kappa-B (NFκB) levels in retinochoroidal tissue were determined. Histopathological examination was performed and retinochoroidal changes were scored. Results. Eritoran treatment resulted in lower levels of TNF-α, MDA, and NFκB after 12 h which became significant after 24 h. Serum TNF-α and retinochoroidal tissue NFκB levels were similar to control animals at the 24th h of the study. Eritoran significantly reversed histopathological damage after 24 h. Conclusions. Eritoran treatment resulted in less inflammatory damage in terms of serum and retinochoroidal tissue parameters.

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.

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.

Effects of interleukin-1β on vascular reactivity after lipopolysaccharide-induced endotoxic shock in rabbits and its relationship with PKC and Rho kinase

Calcium desensitization plays a critical role in the occurrence of vascular hyporeactivity after shock. Interleukin (IL)-1β participates in the regulation of vascular reactivity via both nitric oxide (NO)-dependent and NO-independent mechanisms. However, the specific NO-independent pathway remains to be established. The issue of whether IL-1β modulates vascular reactivity via regulation of calcium sensitivity in the NO-independent mechanism is unclear. In the current study, effects of IL-1β on vascular calcium sensitivity and its relationship with PKC and Rho kinase were investigated in vivo and in vitro using a rabbit model of lipopolysaccharide (LPS)-induced endotoxic shock and superior mesenteric arteries (SMAs), respectively. The calcium sensitivity profile of SMAs displayed a biphasic change after LPS-induced endotoxic shock (significant increase at 0.5 hour and 1 hour after LPS administration and marked decrease after 2 hours) and was negatively related to changes in serum IL-1β. The IL-1 receptor antagonist, IL-1ra (4 μg/mL), partly reversed LPS-induced calcium desensitization. In vitro incubation with IL-1β (50-200 ng/mL) reduced the calcium sensitivity of SMAs and suppressed the activities of Rho kinase and PKC and the phosphorylation of 20-kDa myosin light chain. These effects of IL-1β were shown to be regulated by the PKC agonist, phorbol 12-myristate 13-acetate, and Rho kinase agonist and antagonist, angiotensin II, and Y-27632, respectively. Our results collectively suggest that IL-1β participates in vascular hyporeactivity after endotoxic shock via regulation of vascular calcium sensitivity. Moreover, this regulatory effect of IL-1β seems closely related to downregulation of the activities of PKC and Rho kinase.

Role of cytokines as a double-edged sword in sepsis

BACKGROUND

Sepsis is a deadly immunological disorder and its pathophysiology is still poorly understood. We aimed to determine if specific pro-inflammatory and anti-inflammatory cytokines can be used as diagnostic and therapeutic targets for sepsis.

MATERIALS AND METHODS

Recent publications in the MEDLINE database were searched for articles regarding the clinical significance of inflammatory cytokines in sepsis.

RESULTS

In response to pathogen infection, pro-inflammatory cytokines [interleukin-6 (IL-6), IL-8, IL-18 and tumor necrosis factor-α (TNF-α)] and anti-inflammatory cytokine (IL-10) increased in patients with sepsis. Importantly, a decrease in IL-6 was associated with a better prognosis and overproduction of IL-10 was found to be the main predictor of severity and fatal outcome.

CONCLUSION

Both pro-inflammatory and anti-inflammatory cytokines constitute a double-edged sword in sepsis; on one hand they are critical to eliminate the infection while on the other, excessive production can cause tissue and organ damage. Increase in cytokines such as IL-6, Il-8, IL-10, IL-18 and TNF-α may have implications in diagnosis and treatment of sepsis.

The dichotomy of inhibiting nuclear factor kappa-B in pneumonia

Activation of nuclear factor kappa-B (NF-κB) results in its translocation from the cytoplasm to the nucleus and binding to the promoters of a large number of genes, including those encoding proinflammatory cytokines and other mediators that can contribute to organ system dysfunction in severe infection. While inhibition of NF-κB activation has been proposed as a therapeutic approach in critical illness, several studies have indicated that such an approach may have deleterious effects in persistent infectious states, such as pneumonia. A new report from Devaney and colleagues shows that while inhibition of NF-κB may be useful in severe pneumonia associated with rapid progression to mortality, it leads to worsened pulmonary injury with increased bacterial numbers in the lungs in a model of prolonged pneumonia. Such data raise concerns about therapeutic approaches targeting NF-κB in critically ill patients with persistent infection.

Inhibition of IκB kinase reduces the multiple organ dysfunction caused by sepsis in the mouse

Nuclear factor κB (NF-κB) plays a pivotal role in sepsis. Activation of NF-κB is initiated by the signal-induced ubiquitylation and subsequent degradation of inhibitors of kappa B (IκBs) primarily via activation of the IκB kinase (IKK). This study was designed to investigate the effects of IKK inhibition on sepsis-associated multiple organ dysfunction and/or injury (MOD) and to elucidate underlying signaling mechanisms in two different in vivo models: male C57BL/6 mice were subjected to either bacterial cell wall components [lipopolysaccharide and peptidoglycan (LPS/PepG)] or underwent cecal ligation and puncture (CLP) to induce sepsis-associated MOD. At 1 hour after LPS/PepG or CLP, mice were treated with the IKK inhibitor IKK 16 (1 mg/kg body weight). At 24 hours, parameters of organ dysfunction and/or injury were assessed in both models. Mice developed a significant impairment in systolic contractility (echocardiography), and significant increases in serum creatinine, serum alanine aminotransferase and lung myeloperoxidase activity, thus indicating cardiac dysfunction, renal dysfunction, hepatocellular injury and lung inflammation, respectively. Treatment with IKK 16 attenuated the impairment in systolic contractility, renal dysfunction, hepatocellular injury and lung inflammation in LPS/PepG-induced MOD and in polymicrobial sepsis. Compared with mice that were injected with LPS/PepG or underwent CLP, immunoblot analyses of heart and liver tissues from mice that were injected with LPS/PepG or underwent CLP and were also treated with IKK 16 revealed: (1) significant attenuation of the increased phosphorylation of IκBα; (2) significant attenuation of the increased nuclear translocation of the NF-κB subunit p65; (3) significant attenuation of the increase in inducible nitric oxide synthase (iNOS) expression; and (4) a significant increase in the phosphorylation of Akt and endothelial nitric oxide synthase (eNOS). Here, we report for the first time that delayed IKK inhibition reduces MOD in experimental sepsis. We suggest that this protective effect is (at least in part) attributable to inhibition of inflammation through NF-κB, the subsequent decrease in iNOS expression and the activation of the Akt-eNOS survival pathway.

Distinctive cytokines as biomarkers predicting fatal outcome of severe Staphylococcus aureus bacteremia in mice

Invasive Staphylococcus aureus infections are frequently associated with bacteraemia. To support clinical decisions on antibiotic therapy, there is an urgent need for reliable markers as predictors of infection outcome. In the present study in mice, bacteraemia was established by intravenous inoculation of a clinical S. aureus isolate at the LD₅₀ inoculum. As potential biomarkers for fatal outcome, blood culture (qualitative and quantitative), serum levels of C-reactive protein (CRP), as well as 31 selected cytokines and chemokines were assessed during the first three days of infection. A positive S. aureus blood culture, the quantitative blood culture, CRP levels, and levels of eight cytokines were indicative for the presence of S. aureus bacteraemia. However, only tumor necrosis factor (TNF) α, interleukin (IL) 1α, and keratinocyte chemoattractant (KC; a functional homologue of human IL-8) were each significantly elevated in eventually non-surviving infected mice versus eventually surviving infected mice. In severe S. aureus bacteraemia in mice, TNF-α, IL-1α, and KC are biomarkers predicting fatal outcome of infection. KC was a biomarker elevated irrespective the progression of infection, which is very interesting regarding clinical application in view of the heterogeneity of patients experiencing bacteraemia in this respect.

Pharmaconutrition: acute fatty acid modulation of circulating cytokines in elderly patients in the ICU

BACKGROUND

Enteral supply of ω-3 polyunsaturated fatty acids has been used in an attempt to modulate inflammation and improve outcome in critically ill patients. However, enteral administration may be slow to change membrane composition and therefore may not be the best route to supply these fatty acids in patients with acute conditions. This study evaluated the effects of short-term intravenous (IV) administration of fish oil-based lipid emulsion (FLE) as pharmaconutrition on cytokine levels in critically ill elderly patients.

METHODS

Enterally fed patients (n = 40; aged 60-80 years) were recruited in the first 48 hours of intensive care unit (ICU) admission. Fifteen patients received IV FLE (0.2 g/kg body weight) over 6 hours for 3 consecutive days, and 25 patients did not receive IV lipid (control). Samples were collected before and 24 hours and 72 hours after the third FLE infusion. Nutrient intakes, clinical parameters, and serum cytokine concentrations were measured.

RESULTS

Compared with the control, FLE resulted in higher energy intake, lower serum tumor necrosis factor-α and interleukin (IL)-8 concentrations, and higher serum IL-10. These differences occurred around 7-9 days of ICU stay at the time of the patient's extubation. ICU stay, mortality, and markers of coagulation and liver function did not differ between groups.

CONCLUSIONS

Short-term IV FLE modulates some inflammatory markers in critically ill elderly patients receiving enteral nutrition (EN), suggesting an anti-inflammatory effect. This may be a benefit and suggests a role for FLE administration as a supplement in elderly ICU patients receiving standard EN.

Curcumin modulates the inflammatory response and inhibits subsequent fibrosis in a mouse model of viral-induced acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) is a clinical syndrome characterized by diffuse alveolar damage usually secondary to an intense host inflammatory response of the lung to a pulmonary or extrapulmonary infectious or non-infectious insult often leading to the development of intra-alveolar and interstitial fibrosis. Curcumin, the principal curcumoid of the popular Indian spice turmeric, has been demonstrated as an anti-oxidant and anti-inflammatory agent in a broad spectrum of diseases. Using our well-established model of reovirus 1/L-induced acute viral pneumonia, which displays many of the characteristics of the human ALI/ARDS, we evaluated the anti-inflammatory and anti-fibrotic effects of curcumin. Female CBA/J mice were treated with curcumin (50 mg/kg) 5 days prior to intranasal inoculation with 10(7)pfu reovirus 1/L and daily, thereafter. Mice were evaluated for key features associated with ALI/ARDS. Administration of curcumin significantly modulated inflammation and fibrosis, as revealed by histological and biochemical analysis. The expression of IL-6, IL-10, IFNγ, and MCP-1, key chemokines/cytokines implicated in the development of ALI/ARDS, from both the inflammatory infiltrate and whole lung tissue were modulated by curcumin potentially through a reduction in the phosphorylated form of NFκB p65. While the expression of TGFß1 was not modulated by curcumin, TGFß Receptor II, which is required for TGFß signaling, was significantly reduced. In addition, curcumin also significantly inhibited the expression of α-smooth muscle actin and Tenascin-C, key markers of myofibroblast activation. This data strongly supports a role for curcumin in modulating the pathogenesis of viral-induced ALI/ARDS in a pre-clinical model potentially manifested through the alteration of inflammation and myofibroblast differentiation.

Protective effects of polydatin on septic lung injury in mice via upregulation of HO-1

The present study was carried out to investigate the effects and mechanisms of polydatin (PD) in septic mice. The model of cecal ligation and puncture (CLP-)induced sepsis was employed. Pretreatment of mice with PD (15, 45, and 100 mg/kg) dose-dependently reduced sepsis-induced mortality and lung injury, as indicated by alleviated lung pathological changes and infiltration of proteins and leukocytes. In addition, PD inhibited CLP-induced serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production, lung cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) protein expressions and NF-κB activation. Notably, PD upregulated the expression and activity of heme oxygenase (HO-)1 in lung tissue of septic mice. Further, the protective effects of PD on sepsis were abrogated by ZnPP IX, a specific HO-1 inhibitor. These findings indicated that PD might be an effective antisepsis drug.

Anti-inflammatory effects of mangiferin on sepsis-induced lung injury in mice via up-regulation of heme oxygenase-1

Sepsis, a serious unbalanced hyperinflammatory condition, is a tremendous burden for healthcare systems, with a high mortality and limited treatment. Increasing evidences indicated that some active components derived from natural foods have potent anti-inflammatory properties. Here we show that mangiferin (MF), a natural glucosyl xanthone found in both mango and papaya, attenuates cecal ligation and puncture-induced mortality and acute lung injury (ALI), as indicated by reduced systemic and pulmonary inflammatory responses. Moreover, pretreatment with MF inhibits sepsis-activated mitogen-activated protein kinases and nuclear factor kappa-light-chain-enhancer of activated B cells signaling, resulting in inhibiting production of proinflammatory mediators. Notably, MF dose-dependently up-regulates the expression and activity of heme oxygenase (HO)-1 in the lung of septic mice. Further, these beneficial effects of MF on the septic lung injury were eliminated by ZnPP IX, a specific HO-1 inhibitor. Our results suggest that MF attenuates sepsis by up-regulation of HO-1 that protects against sepsis-induced ALI through inhibiting inflammatory signaling and proinflammatory mediators. Thereby, MF may be effective in treating sepsis with ALI.

In vivo transfection of nuclear factor κB decoy protects pulmonary function against acute lung contusion in rabbits

BACKGROUND

The transcription factor nuclear factor κB (NF-κB) regulates the expression of numerous proinflammatory factors that may exacerbate the response to acute injury. We investigated the effect of an inhibitory NF-κB decoy oligodeoxynucleotide on proinflammatory factor expression and pulmonary function after acute lung contusion in rabbits.

METHODS

Thirty-minutes after acute lung contusion, the NF-κB decoy or a scrambled control oligodeoxynucleotide was injected via the jugular vein. Blood samples were collected for blood gas analysis and plasma tumor necrosis factor α, interleukin 1β (IL-1β), IL-13, and IL-10 were measured by enzyme-linked immunosorbent assay at 1, 2, 3, and 4 hours after contusion. In addition, NF-κB protein expression in lung tissue was detected by Western blot analysis.

RESULTS

The blood PO2 decreased immediately after lung contusion, whereas PAO2 increased significantly, indicative of disrupted respiratory function. Respiratory function improved after sense NF-κB decoy injection but not after injection of the inactive scrambled form. Injection of NF-κB decoy resulted in significant inhibition of NF-κB protein expression in lung tissue and a reduction in the serum concentrations of proinflammatory cytokines tumor necrosis factor α and IL-1β compared with those of control rabbits injected with the scrambled decoy. In contrast, serum levels of the anti-inflammatory cytokines IL-10 and IL-13 increased after decoy injection compared with those of control animals and rabbits injected with the scrambled decoy.

CONCLUSION

The sense NF-κB decoy protected respiratory function and reduced serum proinflammatory factor secretion after acute lung contusion. Inhibition of NF-κB may allow for preservation of pulmonary function for patients with acute lung injury.

Diacerhein attenuates the inflammatory response and improves survival in a model of severe sepsis

INTRODUCTION

Hyperglycemia and insulin resistance have been associated with a worse outcome in sepsis. Although tight glycemic control through insulin therapy has been shown to reduce morbidity and mortality rates, the effect of intensive insulin therapy in patients with severe sepsis is controversial because of the increased risk of serious adverse events related to hypoglycemia. Recently, knowledge about diacerhein, an anthraquinone drug with powerful antiinflammatory properties, revealed that this drug improves insulin sensitivity, mediated by the reversal of chronic subclinical inflammation. The aim of the present study was to evaluate whether the antiinflammatory effects of diacerhein after onset of sepsis-induced glycemic alterations is beneficial and whether the survival rate is prolonged in this situation.

METHODS

Diffuse sepsis was induced by cecal ligation and puncture surgery (CLP) in male Wistar rats. Blood glucose and inflammatory cytokine levels were assessed 24 hours after CLP. The effect of diacerhein on survival of septic animals was investigated in parallel with insulin signaling and its modulators in liver, muscle, and adipose tissue.

RESULTS

Here we demonstrated that diacerhein treatment improves survival during peritoneal-induced sepsis and inhibits sepsis-induced insulin resistance by improving insulin signaling via increased insulin-receptor substrate-1-associated phosphatidylinositol 3-kinase activity and Akt phosphorylation. Diacerhein also decreases the activation of endoplasmic reticulum stress signaling that involves upregulation of proinflammatory pathways, such as the I kappa B kinase and c-Jun NH2-terminal kinase, which blunts insulin-induced insulin signaling in liver, muscle, and adipose tissue. Additionally, our data show that this drug promoted downregulation of proinflammatory signaling cascades that culminate in transcription of immunomodulatory factors such interleukin (IL)-1β, IL-6, and tumor necrosis factor-α.

CONCLUSIONS

This study demonstrated that diacerhein treatment increases survival and attenuates the inflammatory response with a significant effect on insulin sensitivity. On the basis of efficacy and safety profile, diacerhein represents a novel antiinflammatory therapy for management of insulin resistance in sepsis and a potential approach for future clinical trials.

Bench-to-bedside review: Neonatal sepsis-redox processes in pathogenesis

The present review is aimed at elucidating the neonatal 'sepsis redox cycle' - the cascade of inflammatory and redox events involved in the pathogenesis of sepsis in neonates. While adult and neonatal sepses share some common features, there are some substantial differences: higher mortality rates occur in adult sepsis and worse long-term effects are evident in neonatal sepsis survivors. Such epidemiological data may be explained by the lower ability of IL6 and IL8 to activate NF-κB-regulated transcription in neonatal sepsis in comparison to TNF-α, which is involved in the mechanisms of adult sepsis. The activation of NF-κB in neonatal sepsis is further promoted by hydrogen peroxide and results in mitochondrial dysfunction and energy failure as septic neonates experience decreased O₂ consumption as well as lower heat production and body temperature in comparison to healthy peers. In neonates, specific organs that are still under development are vulnerable to sepsis-provoked stress, which may lead to brain, lung, and heart injury, as well as vision and hearing impairments. In the light of the processes integrated here, it is clear that therapeutic approaches should also target specific steps in the neonatal 'sepsis redox cycle' in addition to the current therapeutic approach that is mainly focused on pathogen eradication.

Effects of ghrelin on pulmonary NOD2 mRNA expression and NF-κB activation when protects against acute lung injury in rats challenged with cecal ligation and puncture

BACKGROUND

Many studies have shown that ghrelin can down-regulate inflammatory cytokine expression via the inhibition of NF-κB activity and therefore, its administration to septic patients is considered beneficial. However, our knowledge of ghrelin's effects on the upstream activators of the NF-κB pathway, such as NOD2, is still limited. This study aimed to investigate the possible involvement of the NOD2 signaling pathway in the anti-inflammatory effects of ghrelin.

METHODS

Twenty-four male SD rats received cecal ligation and puncture (CLP) or sham operation, followed by infusion of saline or ghrelin. The lungs were harvested 6h after CLP or sham operation and analyzed for lung histopathology, neutrophil infiltration, inflammatory cytokines (TNF-α, and IL-6), NOD2 mRNA expression, and activation of NF-κB. Furthermore, survival was recorded for ten days in additional groups of rats.

RESULTS

Compared with sham group, neutrophil infiltration, TNF-α and IL-6 levels, NOD2 mRNA expression, as well as NF-κB activation in lungs from rats undergoing CLP were significantly increased. After the administration of ghrelin, all inflammatory parameters analyzed were lower than those without ghrelin following CLP. In addition, ghrelin improved survival after CLP.

CONCLUSION

Our results indicate that in a CLP model of sepsis, the beneficial effects that ghrelin has on inflammatory outcomes are mediated at least in part through inhibition of NOD2 expression upstream of NF-κB.

Bench-to-bedside review: sepsis - from the redox point of view

The pathogenesis of sepsis and its progression to multiple organ dysfunction syndrome and septic shock have been the subject of investigations for nearly half a century. Controversies still exist with regard to understanding the molecular pathophysiology of sepsis in relation to the complex roles played by reactive oxygen species, nitric oxide, complements and cytokines. In the present review we categorise the key turning points in sepsis development and outline the most probable sequence of events leading to cellular dysfunction and organ failure under septic conditions. We have applied an integrative approach in order to fuse current state-of-the-art knowledge about redox processes involving hydrogen peroxide, nitric oxide, superoxide, peroxynitrite and hydroxyl radical, which lead to mitochondrial respiratory dysfunction. Finally, from this point of view, the potential of redox therapy targeting sepsis is discussed.

Constitutive intestinal NF-κB does not trigger destructive inflammation unless accompanied by MAPK activation

Constitutive NF-κB activation in IECs induces inflammatory cytokines and chemokines in the lamina propria, but does not result in overt tissue damage unless acute inflammatory insults are present, causing TNF-dependent destruction and barrier disruption.

Nuclear factor (NF)-κB, activated by IκB kinase (IKK), is a key regulator of inflammation, innate immunity, and tissue integrity. NF-κB and one of its main activators and transcriptional targets, tumor necrosis factor (TNF), are up-regulated in many inflammatory diseases that are accompanied by tissue destruction. The etiology of many inflammatory diseases is poorly understood, but often depends on genetic factors and environmental triggers that affect NF-κB and related pathways. It is unknown, however, whether persistent NF-κB activation is sufficient for driving symptomatic chronic inflammation and tissue damage. To address this question, we generated IKKβ(EE)^IEC mice, which express a constitutively active form of IKKβ in intestinal epithelial cell (IECs). IKKβ(EE)^IEC mice exhibit NF-κB activation in IECs and express copious amounts of inflammatory chemokines, but only small amounts of TNF. Although IKKβ(EE)^IEC mice exhibit inflammatory cell infiltration in the lamina propria (LP) of their small intestine, they do not manifest tissue damage. Yet, upon challenge with relatively mild immune and microbial stimuli, IKKβ(EE)^IEC mice succumb to destructive acute inflammation accompanied by enterocyte apoptosis, intestinal barrier disruption, and bacterial translocation. Inflammation is driven by massive TNF production, which requires additional activation of p38 and extracellular-signal–regulated kinase mitogen-activated protein kinases (MAPKs).

Bacteria-specific neutrophil dysfunction associated with interferon-stimulated gene expression in the acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a poorly understood condition with greater than 30% mortality. Massive recruitment of neutrophils to the lung occurs in the initial stages of the ARDS. Significant variability in the severity and duration of ARDS-associated pulmonary inflammation could be linked to heterogeneity in the inflammatory capacity of neutrophils. Interferon-stimulated genes (ISGs) are a broad gene family induced by Type I interferons. While ISGs are central to anti-viral immunity, the potential exists for these genes to evoke extensive modification in cellular response in other clinical settings. In this prospective study, we sought to determine if ISG expression in circulating neutrophils from ARDS patients is associated with changes in neutrophil function. Circulating neutrophil RNA was isolated, and hierarchical clustering ranked patients' expression of three ISGs. Neutrophil response to pathogenic bacteria was compared between normal and high ISG-expressing neutrophils. High neutrophil ISG expression was found in 25 of 95 (26%) of ARDS patients and was associated with reduced migration toward interleukin-8, and altered responses to Staphylococcus aureus, but not Pseudomonas aeruginosa, which included decreased p38 MAP kinase phosphorylation, superoxide anion release, interleukin-8 release, and a shift from necrotic to apoptotic cell death. These alterations in response were reflected in a decreased capacity to kill S. aureus, but not P. aeruginosa. Therefore, the ISG expression signature is associated with an altered circulating neutrophil response phenotype in ARDS that may predispose a large subgroup of patients to increased risk of specific bacterial infections.

Leptin and the post-operative inflammatory response. More insights into the correlation with the clinical course and glucocorticoid administration

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) causes a systemic inflammatory process which can lead to multiple organ failure and postoperative morbidity. Recent animal and human studies suggested a possible involvement of leptin in the systemic inflammatory response.

AIM

To characterize the response of leptin to open heart surgery (OHS) and the relationship between the time course of leptin levels and the post-operative clinical course, and to examine the effect of exogenous glucocorticoids.

PATIENTS AND METHODS

Forty-seven pediatric patients, undergoing OHS for congenital heart disease were studied. Thirty-four patients (Group 1) received methylprednisolone during CPB while 13 (group 2) did not. Serial blood samples were collected perioperatively and up to 24 h after surgery, and assayed for leptin and cortisol.

RESULTS

All patients' leptin levels decreased significantly during CPB (to 44-48% of baseline, p<0.001); they then increased, peaking at 12 h post-operatively. The levels of groups 1 and 2 were similar up to 8 h post-operatively; thereafter, those of group 1 were significantly higher. Recovery of leptin levels in patients with a more complicated post-operative course was comparatively slower. Cortisol levels of all patients increased significantly during CPB (p<0.001), gradually decreasing afterwards. Cortisol and leptin levels were inversely correlated in both patients' groups.

CONCLUSIONS

CPB is associated with acute changes in circulating leptin levels. A complicated postoperative course is associated with lower leptin levels which are inversely correlated with cortisol levels. Leptin may participate in post-CPB inflammatory and hemodynamic responses.

Expression of inflammation-associated genes in circulating leukocytes collected from horses with gastrointestinal tract disease

OBJECTIVE

To investigate whether expression of inflammation-associated genes in leukocytes from horses with gastrointestinal tract (GIT) diseases correlated with the type of disease and outcome.

ANIMALS

10 healthy horses and 50 horses with GIT disease.

PROCEDURES

A blood sample was collected from each healthy horse or horse with GIT disease (during admission to the hospital). Leukocytes were isolated, diluted to a standard concentration, and frozen until RNA extraction. Expression of 14 genes associated with inflammation was quantified by use of a real-time quantitative reverse transcription PCR assay. Results were grouped by GIT disease type and disease outcome for comparison.

RESULTS

Horses with GIT disease had colic of unknown etiology (n = 8 horses), GIT inflammation or strangulation (19), or nonstrangulating GIT obstruction (23). Among the 45 horses receiving treatment, 38 were discharged from the hospital, and 7 died or were euthanized. Compared with healthy horses, horses with colic of unknown etiology had similar gene expression. Significant differences in expression of the interleukin-8, leukocyte-selectin molecule, matrix metalloproteinase-9, platelet-selectin molecule, mitochondrial superoxide dismutase, Toll-like receptor 4, and tumor necrosis factor-A genes were detected between healthy horses and horses with GIT disease. Significant differences in expression of the interleukin-1 receptor antagonist, interleukin-8, leukocyte-selectin molecule, matrix metalloproteinase-9, platelet-selectin molecule, mitochondrial superoxide dismutase, Toll-like receptor 4, and tumor necrosis factor-A genes were detected among healthy horses and horses grouped by disease outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Inflammatory gene expression in leukocytes of horses with GIT disease appeared to be related to disease pathogenesis and prognosis.

Bench-to-bedside review: Targeting antioxidants to mitochondria in sepsis

Development of organ dysfunction associated with sepsis is now accepted to be due at least in part to oxidative damage to mitochondria. Under normal circumstances, complex interacting antioxidant defense systems control oxidative stress within mitochondria. However, no studies have yet provided conclusive evidence of the beneficial effect of antioxidant supplementation in patients with sepsis. This may be because the antioxidants are not accumulating in the mitochondria, where they are most needed. Antioxidants can be targeted selectively to mitochondria by several means. This review describes the in vitro studies and animal models of several diseases involving oxidative stress, including sepsis, in which antioxidants targeted at mitochondria have shown promise, and the future implications for such approaches in patients.

Peroxisome proliferator-activated receptor {delta} regulates inflammation via NF-{kappa}B signaling in polymicrobial sepsis

The nuclear peroxisome proliferator-activated receptor δ (PPARδ) is an important regulator of lipid metabolism. In contrast to its known effects on energy homeostasis, its biological role on inflammation is not well understood. We investigated the role of PPARδ in the modulation of the nuclear factor-κB (NF-κB)-driven inflammatory response to polymicrobial sepsis in vivo and in macrophages in vitro. We demonstrated that administration of GW0742, a specific PPARδ ligand, provided beneficial effects to rats subjected to cecal ligation and puncture, as shown by reduced systemic release of pro-inflammatory cytokines and neutrophil infiltration in lung, liver, and cecum, when compared with vehicle treatment. Molecular analysis revealed that treatment with GW0742 reduced NF-κB binding to DNA in lung and liver. In parallel experiments, heterozygous PPARδ-deficient mice suffered exaggerated lethality when subjected to cecal ligation and puncture and exhibited severe lung injury and higher levels of circulating tumor necrosis factor-α (TNFα) and keratinocyte-derived chemokine than wild-type mice. Furthermore, in lipopolysaccharide-stimulated J774.A1 macrophages, GW0742 reduced TNFα production by inhibiting NF-κB activation. RNA silencing of PPARδ abrogated the inhibitory effects of GW0742 on TNFα production. Chromatin immunoprecipitation assays revealed that PPARδ displaced the NF-κB p65 subunit from the κB elements of the TNFα promoter, while recruiting the co-repressor BCL6. These data suggest that PPARδ is a crucial anti-inflammatory regulator, providing a basis for novel sepsis therapies.

A novel fluid resuscitation strategy modulates pulmonary transcription factor activation in a murine model of hemorrhagic shock

INTRODUCTION

Combining the hemodynamic and immune benefits of hypertonic saline with the anti-inflammatory effects of the phosphodiesterase inhibitor pentoxifylline (HSPTX) as a hemorrhagic shock resuscitation strategy reduces lung injury when compared with the effects of Ringer's lactate (RL). We hypothesized that HSPTX exerts its anti-inflammatory effects by interfering with nuclear factor kappa B/cAMP response element-binding protein (NF-kappaB-CREB) competition for the coactivator CREB-binding protein (CBP) in lung tissue, thus affecting pro-inflammatory mediator production.

METHODS

Male Sprague-Dawley rats underwent 60 minutes of hemorrhagic shock to reach a mean arterial blood pressure of 35 mmHg followed by resuscitation with either RL or HSPTX (7.5% HS + 25 mg/kg PTX). After four hours, lung samples were collected. NF-kappaB activation was assessed by measuring the levels of phosphorylated cytoplasmic inhibitor of kappa B (I-kappaB) and nuclear NF-kappaB p65 by western blot. NF-kappaB and CREB DNA-binding activity were measured by electrophoretic mobility shift assay (EMSA). Competition between NF-kappaB and CREB for the coactivator CBP was determined by immunoprecipitation. Interleukin-8 (IL-8) levels in the lung were measured by ELISA.

RESULTS

RL resuscitation produced significantly higher levels of lung IL-8 levels, I-kappaB phosphorylation, p65 phosphorylation, and NF-kappaB DNA binding compared with HSPTX. NF-kappaB-CBP-binding activity was similar in both groups, whereas CREB-CBP-binding activity was significantly increased with HSPTX. CREB-DNA binding-activity increased to a greater level with HSPTX compared with RL.

DISCUSSION

HSPTX decreases lung inflammation following hemorrhagic shock compared with conventional resuscitation using RL through attenuation of NF-kappaB signaling and increased CREB-DNA binding activity. HSPTX may have therapeutic potential in the attenuation of ischemia-reperfusion injury observed after severe hemorrhagic shock.

Arginine-enriched total parenteral nutrition improves survival in peritonitis by normalizing NFkappaB activation in peritoneal resident and exudative leukocytes

BACKGROUND

Enteral nutrition maintains peritoneal defense more effectively than parenteral nutrition, at least partly by preserving NFkappaB activation in peritoneal cells. We hypothesized that arginine (ARG)-enriched parenteral nutrition would normalize NFkappaB activation in peritoneal leukocytes, thereby improving the survival of peritonitis models.

METHODS

A total of 105 ICR mice were randomized to chow (n=33), IV feeding of a standard (STD) total parenteral nutrition (STD-TPN) solution (ARG 0.3%) (n=35), or 1% ARG-TPN solution (n=37), and fed accordingly for 5 days.Experiment 1: Thirty mice were used for intranuclear NFkappaB measurement in peritoneal resident cells (PRCs). After incubation with lipopolysaccharide (LPS: 0, 1, 10 microg/mL) for 30 minutes, intranuclear NFkappaB activity was examined by laser scanning cytometry.Experiment 2: Fifty-one mice were injected with 2 mL of 1% glycogen intraperitoneally. Peritoneal exudative cells (PECs) were obtained at 2 or 4 hours after glycogen administration for NFkappaB measurement. Cytokine (TNFalpha, IL-10) levels in peritoneal lavage fluid were also determined by ELISA.Experiment 3: After 5 days of feeding, 24 mice underwent cecal ligation and puncture. Survival was observed up to 5 days.

RESULTS

Experiment 1: Intranuclear NFkappaB levels in the ARG-TPN and chow groups increased dose-dependently after LPS stimulation, while the level in the STD-TPN group was unchanged.Experiment 2: Intranuclear NFkappaB level was significantly higher at 2 hours in the chow than in the STD-TPN group, whereas in the ARG-TPN mice the level was midway between those of the chow and STD-TPN groups. TNFalpha and IL-10 levels of the chow group were significantly higher than those of STD-TPN mice at 2 hours. TNFalpha was significantly higher in the ARG-TPN group than in the STD-TPN group, but the IL-10 level showed no recovery.Experiment 3: Survival times were significantly reduced in the STD-TPN as compared with the chow group, though ARG-TPN improved survival.

CONCLUSION

ARG-enriched TPN is a surrogate for enteral feeding which maintains peritoneal defense by preserving NFkappaB activation in peritoneal resident and exudative leukocytes.

The 2008 ESPEN Sir David Cuthbertson Lecture: Fatty acids and inflammation--from the membrane to the nucleus and from the laboratory bench to the clinic

Many chronic conditions involve excessive inflammation that is damaging to host tissues. Excessive or inappropriate inflammation and immunosuppression are components of the response to surgery, trauma, injury and infection in some individuals and these can lead, progressively, to sepsis and septic shock. Hyperinflammation is characterised by the production of inflammatory cytokines, eicosanoids and other inflammatory mediators, while the immunosuppression is characterised by impairment of antigen presentation and of certain T cell responses. N-6 fatty acids may contribute to the hyperinflamed and immunosuppressed states. N-3 fatty acids from fish oil decrease the production of inflammatory cytokines and eicosanoids. They act both directly (by replacing arachidonic acid as an eicosanoid precursor) and indirectly (by altering the expression of inflammatory genes through effects on transcription factor activation). Thus, these fatty acids are potentially useful anti-inflammatory agents and may be of benefit in patients with chronic inflammatory diseases or at risk of hyperinflammation and sepsis. An emerging application of n-3 fatty acids is in surgical or critically ill patients where they may be added to parenteral or enteral formulas. Studies to date are suggestive of clinical benefits from these approaches, although more robust data are needed especially in critically ill patients.