The pathogenesis of sepsis. Factors that modulate the response to gram-negative bacterial infection

VISTA Re-programs Macrophage Biology Through the Combined Regulation of Tolerance and Anti-inflammatory Pathways

We present the novel finding that V-domain Ig suppressor of T cell activation (VISTA) negatively regulates innate inflammation through the transcriptional and epigenetic re-programming of macrophages. Representative of VISTA re-programming is the ability of VISTA agonistic antibodies to augment LPS tolerance and reduce septic shock lethality in mice. This anti-inflammatory effect of anti-VISTA was mimicked in vitro demonstrating that anti-VISTA treatment caused a significant reduction in LPS-induced IL-12p40, IL-6, CXCL2, and TNF; all hallmark pro-inflammatory mediators of endotoxin shock. Even under conditions that typically "break" LPS tolerance, VISTA agonists sustained a macrophage anti-inflammatory profile. Analysis of the proteomic and transcriptional changes imposed by anti-VISTA show that macrophage re-programming was mediated by a composite profile of mediators involved in both macrophage tolerance induction (IRG1, miR221, A20, IL-10) as well as transcription factors central to driving an anti-inflammatory profile (e.g., IRF5, IRF8, NFKB1). These findings underscore a novel and new activity of VISTA as a negative checkpoint regulator that induces both tolerance and anti-inflammatory programs in macrophages and controls the magnitude of innate inflammation in vivo.

Identification and evaluation of anti-inflammatory properties of aqueous components extracted from sesame (Sesamum indicum) oil

We previously reported that sesame oil (SO) has anti-inflammatory, anti-atherosclerotic and lipid lowering properties in vivo. Our recent studies have shown that, an aqueous extract of sesame oil (SOAE) has also anti-inflammatory and anti-atherosclerotic properties but with no lipid lowering effects. The extent of reduction in atherosclerosis led us to identify components of SOAE and evaluate their anti-inflammatory properties in vitro. Liquid chromatography mass spectrometric method was used to detect and identify components of SOAE. Methoxyphenol derivatives, short and long chain carboxylic acids, dicarboxylic acids, hydroxy and oxo- carboxylic acids were detected. To our surprise, sesamol and its derivatives (lignans), were not present in the SOAE. Among the identified, a combination of methoxy phenol compounds were selected and tested their ability to reduce LPS induced inflammatory gene expression. Monocyte derived macrophages/RAW 264.7 macrophages were pre-treated with these compounds for 2 h, followed by LPS stimulation for 24 h and pro-inflammatory gene expressions were analyzed. These methoxyphenol derivatives showed potent anti-inflammatory properties. In conclusion, the anti-inflammatory molecules associated with SO may contribute the anti-inflammatory and anti-atherosclerotic properties. Also, our results shed light for the development of SOAE based non-pharmacological therapeutics, nutritional supplements and health products for various inflammatory diseases in the future.

Combination of Pelargonium sidoides and Coptis chinensis root inhibits nuclear factor kappa B-mediated inflammatory response in vitro and in vivo

Background

Pelargonium sidoides (PS) and Coptis chinensis root (CR) have traditionally been used to treat various diseases, including respiratory and gastrointestinal infections, dysmenorrhea, and hepatic disorders. The present study was conducted to evaluate the anti-inflammatory effects of a combination of PS and CR in vitro and in vivo.

Methods

The in vitro effects of PS + CR on the induction of inflammation-related proteins were evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The levels of nitric oxide (NO) and of inflammatory cytokines and prostaglandin E₂ (PGE₂) were measured using the Griess reagent and enzyme-linked immunosorbent assay (ELISA) methods, respectively. The expression of inflammation-related proteins was confirmed by Western blot. Additionally, the effects of PS + CR on paw edema volume, skin thickness, and numbers of infiltrated inflammatory cells, mast cells, COX-2-, iNOS-, and TNF-α-immunoreactive cells in dorsum and ventrum pedis skin were evaluated in a rat model of carrageenan (CA)-induced paw edema.

Results

PS + CR significantly reduced production of NO, PGE₂ and three pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6) and also decreased levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Treatment with PS + CR significantly reduced the protein expression levels of LPS-stimulated nuclear factor kappa B (NF-κB) and phosphorylated inhibitor of NF-κB (p-I-κBα). Additionally, PS + CR significantly inhibited the increases in paw swelling, skin thickness, infiltrated inflammatory cells, mast cell degranulation, COX-2-, iNOS-, and TNF-α-immunoreactive cells in the rat model of CA-induced acute edematous paw.

Conclusions

These results demonstrate that PS + CR exhibits anti-inflammatory properties through decreasing the production of pro-inflammatory mediators (NO, PGE₂, TNF-α, IL-1β, and IL-6), suppressing NF-κB signaling in LPS-induced RAW 264.7 cells. Additionally, the results of the CA-induced rat paw edema assay revealed an anti-edema effect of PS + CR. Furthermore, it is suggested that PS + CR also inhibits acute edematous inflammation by suppressing mast cell degranulation and inflammatory mediators (COX-2, iNOS, and TNF-α). Thus, PS + CR may be a potential candidate for the treatment of various inflammatory diseases, and it may also contribute to a better understanding of the molecular mechanisms underlying inflammatory response regulation.

Enrofloxacin in therapeutic doses alters cytokine production by porcine PBMCs induced by lipopolysaccharide

The effect of enrofloxacin on cytokine secretion by porcine peripheral blood mononuclear cells (PBMCs) was studied. Twenty 8-20-week-old pigs were randomly divided into two groups: control (C, n = 10) and experimental (E, n = 10) were used. Pigs from group E received enrofloxacin at therapeutic dose for 5 consecutive days. Blood samples were collected at 0 (before antibiotic administration), 2, 4 (during antibiotic therapy) 6, 9, 14 21, 35, 49, and 63 d of study (after treatment). PBMCs of pigs from both groups were incubated with or without lipopolysaccharide (LPS). Ex vivo production on interleukin (IL)-4, IL-6, IL-10, INF-γ, and TNF-α were analyzed using ELISA assay. Intramuscular administration of enrofloxacin to healthy pigs for 5 consecutive days induced a transitory reduction of the ex vivo response of PBMCs to LPS in terms of IL-6 and TNF-α secretion. The level of IL-6 returned to day 0 level shortly after end of treatment, while the TNF-α production remained reduced 10 d after the end of treatment. Our results indicate that enrofloxacin given in vivo in therapeutic doses has an immunomodulatory effect through its capacity to inhibit ex vivo secretion of IL-6 and TNF-α by porcine PBMC after LPS stimulation.

Cheongsangbangpung-tang ameliorated the acute inflammatory response via the inhibition of NF-κB activation and MAPK phosphorylation

Background

Cheongsangbangpung-tang (CBT) is a traditional herbal formula used in Eastern Asia to treat heat-related diseases and swellings in the skin. The present study was conducted to evaluate the anti-inflammatory effects of cheongsangbangpung-tang extract (CBTE) both in vitro and in vivo.

Methods

The in vitro effects of CBTE on the lipopolysaccharide (LPS)-induced production of inflammation-related proteins were examined in RAW 264.7 cells. The levels of nitric oxide (NO) were measured with the Griess reagent. Inflammatory cytokines and prostaglandin E₂ (PGE₂) were detected using the enzyme-linked immunosorbent assay (ELISA) method. Inflammation-related proteins were detected by Western blot. The effect of CBTE on acute inflammation in vivo was evaluated using carrageenan (CA)-induced paw oedema. To evaluate the anti-inflammatory effect, paw oedema volume, thickness of the dorsum and ventrum pedis skin, number of infiltrated inflammatory cells, and number of COX-2-, iNOS-immunoreactive cells were measured.

Results

In an in vitro study, CBTE inhibited the production of NO and PGE₂ and also decreased the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) activity, interleukin (IL)-1β, IL-6 and tumuor necrosis factor-α. In LPS-activated macrophages, nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signalling is a pivotal pathway in the inflammatory process. These plausible molecular mechanisms increased the phosphorylation of I-κBα, while the activation of NF-κB and the phosphorylation of MAPK by LPS were blocked by CBTE treatment. In our in vivo study, a CA-induced acute oedematous paw inflammation rat model was used to evaluate the anti-inflammatory effect of CBTE. CBTE significantly reduced the increases in paw swelling, skin thicknesses, infiltrated inflammatory cells and iNOS-, COX-2 positive cells induced by CA injection.

Conclusions

Based on these results, CBTE should favourably inhibit the acute inflammatory response through modulation of NF-κB activation and MAPK phosphorylation. Furthermore, the inhibition of CBTE in rat paw oedema induced by CA is considered to be clear evidence that CBTE may be a useful source to treat inflammation.

The Management of Sepsis: A Practical Review

The incidence of the sepsis syndrome has increased dramatically in the last few decades. During this time we have gained new insights into the pathophysiologic mechanisms leading to organ dysfunction in sepsis and the importance of the host-bacterial interactions in mediating many of these processes. This knowledge has led to new therapeutic approaches and the investigation of a number of novel agents. An assessment of these approaches is presented to aid clinicians in the management of patients with severe sepsis. Criteria used to select studies included their relevance to the management of sepsis and their pertinence to clinicians. Appropriate antibiotic selection and volume resuscitation remain the cornerstone of treatment of septic patients. Hydroxyethyl starch solutions have theoretical advantages over crystalloids; there is, however, no data that the type of resuscitation fluid alters outcome. Vasoactive agents are required in patients who remain hemodynamically unstable or have evidence of tissue hypoxia after adequate volume resuscitation. Although dopamine is widely used, dobutamine and norepinephrine are our vasoactive agents of choice. Dopamine has no proven role in oliguric patients, with early dialysis recommended in patients with acute renal failure. The preferred method of renal replacement therapy remains to be determined. Blood products should be used cautiously in patients with disseminated intravascular coagulation. Therapeutic strategies that interfere with the immune system have not been proven to improve the outcome in unselected groups of patients. However, immunomodulation may prove to have a role in select subgroups of patients. Antibiotic therapy and intensive physiological support continues to be the main approach to the management of patients with severe sepsis. Despite the development of numerous novel therapeutic agents, these drugs have not been demonstrated to improve patient outcome.

IC14, a CD14 specific monoclonal antibody, is a potential treatment for patients with severe sepsis

CD14 is a pattern recognition receptor for the bacterial cell wall components from Gram-positive and Gram-negative bacteria as well as mycobacteria. Binding of lipopolysaccharide (LPS) or other cell wall constituents to CD14 initiates signal transduction through the Toll-like receptors resulting in the release of pro-inflammatory cytokines and the initiation of the systemic inflammatory response. In rabbits and non-human primates, CD14 specific antibodies were shown to attenuate responses to LPS or Escherichia coli challenge including pro-inflammatory cytokine release, acute lung injury, hypotension and changes in lung, liver, spleen and adrenal gland morphology. In healthy human subjects, single doses of a chimeric CD14 antibody (IC14) have been shown to be well tolerated and result in a dose-related degree of saturation of CD14 receptors on monocytes and granulocytes. Pretreatment of healthy subjects with IC14 2 h prior to LPS resulted in an attenuation of the LPS-induced fever, clinical symptoms, and leukocyte activation and degranulation. IC14 inhibited the release of TNF-α, IL-6, and IL-10 and delayed the release of sTNFRI and IL-1ra. Further studies are in progress to characterize the safety and clinical pharmacology of IC14 in patients with severe sepsis.

Thymoquinone modulates nitric oxide production and improves organ dysfunction of sepsis

AIMS

The present investigation was designed to evaluate the effect of thymoquinone in a septic animal model and to explore the role of nitric oxide (NO) in the process.

MAIN METHODS

To achieve this, mice (n=12 per group) were treated in parallel with thymoquinone (0.75mg/kg/day) and/or NG-nitro-l-arginine methyl ester (L-NAME; 400μg/g/day) prior to sepsis induction with live Escherichia coli.

KEY FINDINGS

Thymoquinone significantly improved renal and hepatic functions alone and in combination with L-NAME. This was associated with less NO production and lower oxidative stress in treated animals. Tumor necrosis factor-α concentration with thymoquinone and L-NAME were 36.27±3.41pg/ml and 56.55±5.85pg/ml, respectively, as opposed to 141.11±6.46pg/ml in septic controls. Similarly, Interleukin-1α, 2, 6 and 10 levels decreased significantly upon treatment with thymoquinone and L-NAME as compared with untreated septic animals. NF-κB and NF-κB-DNA binding activity in nuclear proteins were also significantly down-regulated. Vascular responsiveness studies in isolated mouse aortae demonstrated a reduced relaxation to acetylcholine exposure in septic mice treated with thymoquinone.

SIGNIFICANCE

These findings suggest that thymoquinone prevents sequels of the multiple organ failure syndrome of sepsis by modulating the production of NO and its inflammatory sequela, and adjusting vascular responsiveness.

Anti-inflammatory and antioxidant activities of the nonlipid (aqueous) components of sesame oil: potential use in atherosclerosis

Dietary intervention to prevent inflammation and atherosclerosis has been a major focus in recent years. We previously reported that sesame oil (SO) was effective in inhibiting atherosclerosis in low-density lipoprotein-receptor negative mice. We also noted that the levels of many proinflammatory markers were lower in the SO-treated animals. In this study we tested whether the non-lipid, aqueous components associated with SO would have anti-inflammatory and antioxidant effects. Polymerase chain reaction array data indicated that sesame oil aqueous extract (SOAE) was effective in reducing lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophage cells. Expression of inflammatory cytokines such as interleukin (IL)-1α, IL-6, and tumor necrosis factor α (TNF-α) was also analyzed independently in cells pretreated with SOAE followed by inflammatory assault. Effect of SOAE on TNF-α-induced MCP-1 and VCAM1 expression was also tested in human umbilical vein endothelial cells. We observed that SOAE significantly reduced inflammatory markers in both macrophages and endothelial cells in a concentration-dependent manner. SOAE was also effective in inhibiting LPS-induced TNF-α and IL-6 levels in vivo at different concentrations. We also noted that in the presence of SOAE, transcription and translocation of NF-kappaB was suppressed. SOAE was also effective in inhibiting oxidation of lipoproteins in vitro. These results suggest the presence of potent anti-inflammatory and antioxidant compounds in SOAE. Furthermore, SOAE differentially regulated expression of scavenger receptors and increased ATP-binding cassette A1 (ABCA1) mRNA expression by activating liver X receptors (LXRs), suggesting additional effects on lipid metabolism. Thus, SOAE appears multipotent and may serve as a valuable nonpharmacological agent in atherosclerosis and other inflammatory diseases.

Endogenous expression pattern of resolvin D1 in a rat model of self-resolution of lipopolysaccharide-induced acute respiratory distress syndrome and inflammation

Resolvin D1 (RvD1), an endogenous lipid mediator derived from docosahexaenoic acid, has been reported to promote a biphasic activity in anti-inflammatory response and regulate inflammatory resolution. The present study aimed to determine the endogenous expression pattern of RvD1 in a rat model of self-resolution of lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) and inflammation. The ARDS model was induced by administrating LPS (2mg/kg) via tracheotomy in 138 male Sprague-Dawley rats. At specified time points, lung injury and inflammation were respectively assessed by lung histology and analysis of bronchoalveolar lavage fluid and cytokine levels. The expression of endogenous RvD1 was detected by high performance liquid chromatography and tandem mass spectrometry. The results showed that histological lung injury peaked between 6h (LPS6h) and day 3, followed by recovery over 4-10 days after LPS administration. Lung tissue polymorph nuclear cell (PMN) was significantly increased at LPS6h, and peaked between 6h to day 2. The levels of interleukin (IL)-6 and IL-10 were significantly increased at LPS6h and remained higher over day 10 as compared to baseline. Intriguingly, the endogenous RvD1 expression was decreased gradually during the first 3 days, followed by almost completely recovery over days 9-10. The finding indicated that endogenous RvD1 underwent a decrease in expression followed by gradual increase that was basically coincident with the lung injury recovery in a rat model of self-resolution LPS-induced ARDS and inflammation. Our results may help define the optimal therapeutic window for endogenous RvD1 to prevent or treat LPS-induced ARDS and inflammation.

Luteolin Suppresses Inflammatory Mediator Expression by Blocking the Akt/NFκB Pathway in Acute Lung Injury Induced by Lipopolysaccharide in Mice

Acute lung injury (ALI), instilled by lipopolysaccharide (LPS), is a severe illness with excessive mortality and has no specific treatment strategy. Luteolin is an anti-inflammatory flavonoid and widely distributed in the plants. Pretreatment with luteolin inhibited LPS-induced histological changes of ALI and lung tissue edema. In addition, LPS-induced inflammatory responses, including increased vascular permeability, tumor necrosis factor (TNF)-α and interleukin (IL)-6 production, and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), were also reduced by luteolin in a concentration-dependent manner. Furthermore, luteolin suppressed activation of NFκB and its upstream molecular factor, Akt. These results suggest that the protection mechanism of luteolin is by inhibition of NFκB activation possibly via Akt.

Distinctive response of CNS glial cells in oro-facial pain associated with injury, infection and inflammation

Oro-facial pain following injury and infection is frequently observed in dental clinics. While neuropathic pain evoked by injury associated with nerve lesion has an involvement of glia/immune cells, inflammatory hyperalgesia has an exaggerated sensitization mediated by local and circulating immune mediators. To better understand the contribution of central nervous system (CNS) glial cells in these different pathological conditions, in this study we sought to characterize functional phenotypes of glial cells in response to trigeminal nerve injury (loose ligation of the mental branch), infection (subcutaneous injection of lipopolysaccharide--LPS) and to sterile inflammation (subcutaneous injection of complete Freund's adjuvant--CFA) on the lower lip. Each of the three insults triggered a specific pattern of mechanical allodynia. In parallel with changes in sensory response, CNS glial cells reacted distinctively to the challenges. Following ligation of the mental nerve, both microglia and astrocytes in the trigeminal nuclear complex were highly activated, more prominent in the principal sensory nucleus (Pr5) and subnucleus caudalis (Sp5C) area. Microglial response was initiated early (days 3-14), followed by delayed astrocytes activation (days 7-28). Although the temporal profile of microglial and astrocyte reaction corresponded respectively to the initiation and chronic stage of neuropathic pain, these activated glial cells exhibited a low profile of cytokine expression. Local injection of LPS in the lower lip skin also triggered a microglial reaction in the brain, which started in the circumventricular organs (CVOs) at 5 hours post-injection and diffused progressively into the brain parenchyma at 48 hours. This LPS-induced microglial reaction was accompanied by a robust induction of IκB-α mRNA and pro-inflammatory cytokines within the CVOs. However, LPS induced microglial activation did not specifically occur along the pain signaling pathway. In contrast, CFA injection led to minor microglial morphological changes and an induction of IκB-α mRNA in the CVO regions; a significant increase in IL-1β and IL-6 mRNA started only at 48 hours post-injection, when the induced pain-related behavior started to resolve. Our detailed analysis of CNS glial response clearly revealed that both nerve injury and oro-facial infection/inflammation induced CNS glial activation, but in a completely different pattern, which suggests a remarkable plasticity of glial cells in response to dynamic changes in their microenvironment and different potential involvement of this non-neuronal cell population in pathological pain development.

Monoclonal antibody-induced cytokine-release syndrome

Monoclonal antibodies (mAbs) are widely used in anti-inflammatory and tumor therapy. Although effective, mAbs can cause a variety of adverse effects. An important toxicity seen with a few mAbs is cytokine-release syndrome (CRS). These mAbs include: alemtuzumab, muromonab-CD3, rituximab, tosituzumab, CP-870,893, LO-CD2a/BTI-322 and TGN1412. By contrast, over 30 mAbs used clinically are not associated with CRS. In this review, the clinical aspects of CRS, the mAbs associated with CRS, the cytokines involved and putative mechanisms mediating cytokine release will be discussed. This will be followed by a discussion of the poor predictive value of studies in animals and the prospects for creating in vitro screens. Finally, approaches to decreasing the probability of CRS, decreasing the severity or treating CRS, should it occur, will be described.

Ceftiofur attenuates lipopolysaccharide-induced acute lung injury

Ceftiofur is a new broad-spectrum, third-generation cephalosporin antibiotic for veterinary use. Our laboratory has previously been reported that ceftiofur can modulate early cytokine responses and increase mouse survival in endotoxemia. In the present study, we investigated the effect of ceftiofur on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in vivo. Mice were pretreated with ceftiofur 1h before challenge with a dose of 0.5mg/kg LPS. Mice treated with LPS alone showed marked increased TNF-alpha, IL-6, and IL-8 levels in the bronchoalveolar lavage fluid (BALF). When pretreated with 30mg/kg of ceftiofur, the TNF-alpha, IL-6, and IL-8 levels were significantly decreased. In addition, the W/D ratio of the lung tissue and the number of total cells, neutrophils and macrophages in the BALF significantly decreased at 8h after pretreatment with ceftiofur. Furthermore, ceftiofur markedly attenuated the LPS-induced histological alteration. These studies indicate that ceftiofur significantly decreases the inflammation in a murine model of LPS-mediated ALI and may represent a novel prevention strategy for nonspecific inflammation in the lungs.

Protective effects of N-acetylcysteine and beta-glucan pretreatment on oxidative stress in cecal ligation and puncture model of sepsis

This study was designed to compare the effect of pretreatment with N-acetylcysteine (NAC) and beta -glucan (beta GLU) on inflammatory response in a rat model of sepsis. The study was performed in the animal laboratory of the Kahramanmaras Sutcu Imam University, School of Medicine. Forty rats were randomized into four groups (control, sham, NAC, and beta GLU). Control and Sham groups received saline or NAC (200 mg/kg, po) in the NAC group and beta GLU (50 mg/kg, po) in the betaGLU group via intragastric gavage once a day for 10 days and 30 min prior to surgery. Sepsis was induced by cecal ligation and puncture (CLP) in rats. In the NAC, beta GLU, and control groups, a laparotomy was performed with the CLP procedure. In the sham group, laparotomy was performed and cecum was manipulated but not ligated or perforated. TNF-alpha and IL-6 levels were significantly elevated in the control group and decreased in the NAC and beta GLU groups. IL-10 levels were significantly increased in the beta GLU group (p < .05). Superoxide dismutase and catalase levels in the liver tissue were significantly increased in the NAC and beta GLU groups, whereas superoxide dismutase levels were higher in the beta GLU pretreatment group than the NAC pretreatment group (p < 0.05). Malondialdehyde levels in the liver tissue were significantly elevated in the control group and decreased in the NAC and beta GLU groups (p < .05). Prophylactic administration of NAC or beta GLU similarly ameliorated sepsis syndrome by reduction of the proinflammatory cytokines and increase of the anti-inflammatory cytokine levels and accession of cellular antioxidants, which protect cells from oxidative stress, thereby recruiting inflammatory cells into tissue.

Review: variability of host-pathogen interaction

The course of every infection is different. The same pathogen can lead to subclinical, mild, severe or lethal infections in individuals. But is this just chance or determined by individual differences--on the side of the host as well as on the side of the pathogen? If so, we might need to consider these variations for treatment decisions. Indeed, we now understand that genetic polymorphisms and health status represent inborn and acquired risk factors. Similarly, pathogens impress with an increasing number of already identified virulence factors and host response modifiers. The emerging, more complex, view of the factors determining course and outcome of infections promises to enable more tailored and thus, hopefully, more effective treatment decisions.

Lipopolysaccharide induces apoptosis in Carassius auratus lymphocytes, a possible role in pathogenesis of bacterial infection in fish

Lipopolysaccharide (LPS), the endotoxin of Gram-negative bacteria, is capable of eliciting a wide variety of pathophysiological effects, including endotoxin shock, tissue injury and lethality in both humans and animals. It is also a potent stimulant to initiate the proliferation, differentiation and activation of B lymphocytes and macrophages, resulting in changes of inflammatory cytokines, such as TNF-alpha, IL1-beta, IL6, IL-8 and IL-12, and enhancement of immune responses. However, little is known about its effect on the induction of apoptosis in lymphocytes. In the present study, the lymphocytes from Carassius auratus were employed for this purpose. The cells were exposed to LPS at various doses for different time periods. By careful apoptotic characteristic analysis, such as condensation of nuclear chromatin, fragmentation of genomic DNA and formation of apoptotic bodies, it provided the first evidence that LPS had apoptotic-inducing effect on fish lymphocytes in a time- and dose-dependent manner. LPS exposure induced significant increase of intracellular reactive oxygen species (ROS), loss of mitochondrial transmembrane potential (DeltaPsi), depletion of ATP production, down-regulation of Bcl-2 expression, up-regulation of Bax and mitochondrial NO-synthase (mNOS) expression, and selective activation of caspase-9 rather than caspase-8. Each of these observations suggests that the LPS-induced apoptosis in C. auratus lymphocytes occurs largely via the mitochondrial apoptotic pathway. This observation was different from the mechanism behind the LPS-induced apoptosis in mammalian macrophages/thymocytes that occurs via the TNF-alpha-mediated death-receptor pathway. Our study suggested the existence of a possible novel role in the pathogenesis of Gram-negative bacterial infection in fish and even in mammals, which may contribute to the therapy of bacterial diseases. Also, it will help to gain more insights into the mechanisms of septic shock and of LPS-induced immunosuppression and autoimmunity.

Toxicity as a result of immunostimulation by biologics

The immune system has evolved highly effective mechanisms of surveillance and defense against foreign pathogens, and is also thought to act in surveillance and suppression of cancer. Thus, a predominant goal of immune system-based therapies is to normalize or enhance the host immune response in the areas of infectious disease and oncology. This review considers general approaches used for therapeutic immunostimulation, alterations in immune response mechanisms that occur with these treatments and the syndromes that commonly arise as a result of these changes. Because nonclinical studies of these therapies are conducted in animal models as the basis for predicting potential human toxicities, this review also considers the value of nonclinical testing to predict human toxicity.

Genetic regulation of endotoxin-induced airway disease

To identify novel genes regulating the biologic response to lipopolysaccharide (LPS), we used a combination of quantitative trait locus (QTL) analysis and microarray-based gene expression studies of C57BL/6J x DBA/2J(BXD) F2 and recombinant inbred (RI) mice. A QTL affecting pulmonary TNF-alpha production was identified on chromosome 2, and a region affecting both polymorphonuclear leukocyte recruitment and TNF-alpha levels was identified on chromosome 11. Microarray analyses of unchallenged and LPS-challenged BXD RI strains identified approximately 500 genes whose expression was significantly changed by inhalation of LPS. Of these genes, 28 reside within the chromosomal regions identified by the QTL analyses, implicating these genes as high priority candidates for functional studies. Additional high priority candidate genes were identified based on their differential expression in mice having high and low responses to LPS. Functional studies of these genes are expected to reveal important molecular mechanisms regulating the magnitude of biologic responses to LPS.

Dual effect of 3,4-dihydroxyacetophenone on LPS-induced apoptosis in RAW264.7 cells by modulating the production of TNF-alpha

To explore the pharmacological effect of 3,4-dihydroxyacetophenone (DHAP) on the apoptosis of RAW264.7 macrophage cells and the mechanism, RAW264.7 macrophage cells were treated with 100 or 500 mg/L lipopolysaccharide (LPS), with or without 10(-5) mol/L DHAP for 24 h. Trypan blue dye exclusion assay was used to assess cell viability. Cell apoptosis was morphological studied and flow cytometric assay was used. Tumor necrosis factor-alpha (TNF-alpha) level was measured by ELISA methods. IkappaB protein was determined by Western blotting. Our results showed that in 100 mg/L LPS-stimulated macrophages, DHAP enhanced the cell apoptosis while in 500 mg/L LPS-stimulated macrophages, DHAP significantly inhibited the cell apoptosis. In both groups, DHAP increased the level of IkappaB but decreased the level of TNF-alpha. It is concluded that DHAP has dual effect on the apoptosis of RAW 264.7 cells treated with different concentrations of LPS. This effect may be due to the inhibition of activation of NF-kappaB and autocrine production of TNFalpha. Our study suggests that DHAP may have anti-inflammatory effect on LPS-activated macrophages.

Effects of lornoxicam on the physiology of severe sepsis

Introduction

The purpose of the present study was to evaluate the effects of intravenous lornoxicam on haemodynamic and biochemical parameters, serum cytokine levels and patient outcomes in severe sepsis.

Methods

A total of 40 patients with severe sepsis were included, and were randomly assigned (20 per group) to receive either lornoxicam (8 mg administered intravenously every 12 hours for six doses) or placebo. For both groups the following were recorded: haemodynamic parameters (heart rate, mean arterial pressure), nasopharyngeal body temperature, arterial blood gas changes (pH, partial oxygen tension, partial carbon dioxide tension), plasma cytokine levels (IL-1β, IL-2 receptor, IL-6, IL-8, tumour necrosis factor-α), biochemical parameters (lactate, leucocytes, trombocytes, creatinine, total bilirubin, serum glutamate oxalate transaminase), length of stay in the intensive care unit, duration of mechanical ventilation and mortality. All measurements were obtained at baseline (before the start of the study) and at 24, 48 and 72 hours from the start of lornoxicam/placebo administration.

Results

No significant differences were found between the intravenous lornoxicam and placebo groups in major cytokines, duration of ventilation and length of intensive care unit stay, and inspired fractional oxygen/arterial oxygen tension ratio (P > 0.05).

Conclusion

In these patients with severe sepsis, we found intravenous lornoxicam to exert no effect on haemodynamic and biochemical parameters, cytokine levels, or patient outcomes. Because of the small number of patients included in the study and the short period of observation, these findings require confirmation by larger clinical trials of intravenous lornoxicam, administered in a dose titrated manner.

The influence of N-acetyl-L-cystein infusion on cytokine levels and gastric intramucosal pH during severe sepsis

Introduction

The purpose of the present study was to evaluate the effects of continuously infused N-acetyl-L-cystein (NAC) on serum cytokine levels and gastric intramucosal pH in humans suffering from severe sepsis.

Methods

Fifty-three patients were included in the study. In the NAC group (n = 27), after an initial intravenous bolus of NAC (150 mg/kg over 5 min), a continuous intravenous infusion of 12.5 mg/kg per hour was given for 6 hours. Patients in the control group (n = 26) were administered dextrose (5% solution) at the same dosage. We recorded the following: haemodynamic parameters, nasopharyngeal temperature, arterial blood gas changes, plasma cytokine levels, biochemical parameters, intramucosal pH, length of stay in the intensive care unit, duration of of mechanical ventilation and mortality. All measurements were taken at baseline (15 min before the start of the study) and were repeated immediately after the bolus infusion, and at 24 and 48 hours after initiation of the continuous NAC infusion.

Results

No differences were found between groups in levels of the major cytokines, duration of ventilation and intensive care unit stay, gastric intramucosal pH and arterial oxygen tension/inspired fractional oxygen ratio (P > 0.05).

Conclusion

We found that NAC infusion at the doses given did not affect cytokine levels, outcomes, or gastric intramucosal pH in patients with severe sepsis. Because of the limited number of patients included in the study and the short period of observation, our findings need confirmation in larger clinical trials of NAC infused in a dose-titrated manner. However, our results do not support the use of NAC in patients with severe sepsis.

Regulation of nitric oxide consumption by hypoxic red blood cells

The homeostasis of nitric oxide (NO) is attained through a balance between its production and consumption. Shifts in NO bioavailability have been linked to a variety of diseases. Although the regulation of NO production has been well documented, its consumption is largely thought to be unregulated. Here, we have demonstrated that under hypoxic conditions, NO accelerates its own consumption by increasing its entry into RBCs. When RBCs were exposed to NO (1:400 NO/heme ratio) under hypoxic conditions to form HbFe(II)NO, the consumption rate of NO increased significantly. This increase in NO consumption converted the bioactivity of serotonin from a vasodilator to a vasoconstrictor in isolated coronary arterioles. We identified HbFe(II)NO as a potential mediator of accelerated NO consumption. Accelerated NO consumption by HbFe(II)NO-bearing RBCs may contribute to hypoxic pulmonary vasoconstriction and the rebound effect seen on termination of NO inhalation therapy. Furthermore, accelerated NO consumption may exacerbate ischemia-mediated vasospasm and nitrate tolerance. Finally, this phenomenon may be an evolved mechanism to stabilize the vasculature in sepsis.

Cytokine-regulatory activity and therapeutic efficacy of cinnamyl derivatives in endotoxin shock

We characterized the regulatory activity of cinnamyl derivatives and related compounds on pro-inflammatory cytokine production in vitro and in vivo. Among the 51 compounds examined, 7-amino-4-methylcoumarin (AMC) suppressed the production of interleukin-1alpha, interleukin-6 and tumor necrosis factor (TNF)-alpha, and their lipopolysaccharide-induced mRNAs in P388D1 cells. AMC suppressed pro-inflammatory cytokine transcription by reducing the DNA-binding amounts of nuclear factor-kappaB (NF-kappaB) and activator protein 1. Further, oral administration of AMC (30 mg/kg) as well as anti-TNF-alpha and anti-interleukin-1alpha antibodies significantly prevented death from endotoxin shock in mice without body weight loss and toxicity. AMC did not affect basal cytokine levels in control mice but suppressed the rise of systemic pro-inflammatory cytokine level, especially TNF-alpha. Thus, AMC might contribute to the recovery of endotoxin shock mainly by suppressing pro-inflammatory cytokine transcription. AMC may be useful in understanding the regulation and role of cytokine production in the pathogenesis of cytokine-mediated diseases.

Prophylactic N-acetylcysteine decreases serum CRP but not PCT levels and microalbuminuria following major abdominal surgery. A prospective, randomised, double-blinded, placebo-controlled clinical trial

OBJECTIVE

Our objective was to investigate whether short-term infusion of the oxygen free radical scavenger N-acetylcysteine (NAC) administered before and during extensive abdominal surgery could ameliorate the progression of early systemic inflammatory response.

DESIGN

Prospective, randomised, double-blinded, placebo-controlled clinical trial.

SETTING

Twenty-bed intensive care unit in a university hospital.

PATIENTS

Following written informed consent, 100 patients were randomised into NAC and placebo groups. Three patients from the NAC group and four from the placebo group withdrew before the final analysis.

INTERVENTION

The treatment group (n=47) received NAC (150 mg/kg(-1) bolus followed by a continuous infusion of 12 mg/kg(-1)/h(-1)) and the placebo group ( n=46) received the same volume of 5% dextrose during surgery.

MEASUREMENTS AND RESULTS

Serum procalcitonin (PCT), C-reactive protein (CRP) and microalbuminuria was monitored preoperatively, on admission to ICU, then daily during the first 3 postoperative days. For statistical analysis Mann Whitney and Chi-squared tests were used. Patients' clinical course was similar in each group as monitored by the Multiple Organ Dysfunction Scores. There was no significant difference between the two groups regarding PCT and microalbuminuria at any assessment point. Significantly lower CRP levels were found in the NAC group on days 1 and 2 (t(24): median: 84.5 interquartile range: [62-120] vs. 118 [86-137] mg/l; p=0.020; t(48): 136 [103-232] vs. 195 [154-252] mg/l; p=0.013, NAC vs. placebo respectively).

CONCLUSION

In this study, short-term NAC treatment decreased CRP levels, but failed to attenuate any other inflammatory response, as monitored by serum PCT and microalbuminuria. Overall, our results do not support the routine prophylactic use of NAC as a free radical scavenger in abdominal surgery.

Effects of Cl2MDP-encapsulating liposomes in a murine model of Pseudomonas aeruginosa-induced sepsis

Pseudomonas aeruginosa is a pathogen that frequently causes acute lung injury, bacteremia and sepsis in critically ill patients. As tissue macrophages are a major producer of inflammatory mediators that contribute to septic physiology, and are essential for eliminating bacteria from the circulation, we investigated the role of tissue macrophages in the generation of both inflammatory and anti-inflammatory cytokines in septic shock by using our mouse model of P. aeruginosa pneumonia. To see the effects of tissue macrophage depletion, we intravenously injected dichloromethylene-diphosphonate (Cl2MDP)-encapsulating liposomes in mice. Two days after the liposome injection, we instilled cytotoxic P. aeruginosa (PA103) into the lung that disseminates and causes septic shock. After the infection, we collected blood and bronchoalveolar lavage fluids. The samples were then analyzed for TNF-alpha, MIP-2, and IL-10 concentration. We compared these results to control mice that received either liposomes without Cl2MDP or phosphate buffered saline alone. Plasma TNF-alpha, MIP-2, and IL-10 levels were significantly decreased in the tissue macrophage-depleted mice compared to the control groups of mice. Although depletion of tissue macrophages by Cl2MDP-liposome administration did not affect the severity of bacteremia or the survival of infected mice, these results imply that tissue macrophages have a major role in the production of both proinflammatory and anti-inflammatory cytokines in the circulation and in the causing septic physiology associated with P. aeruginosa pneumonia.

Diferuloylmethane inhibits neutrophil infiltration and improves survival of mice in high-dose endotoxin shock

Gram-negative septic shock is a systemic inflammatory response of the body caused primarily by the cell wall component (lipopolysaccharide) of the gram-negative bacteria. During high-dose endotoxin shock, neutrophils infiltrate and accumulate in the liver, causing hepatocellular injury. Cell adhesion molecules, specifically intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), play an important role in the infiltration of neutrophils in the liver tissue. In this study, we demonstrate that diferuloylmethane exerts protective effect in high-dose endotoxin shock by improving survival and reducing the severity of endotoxin shock symptoms such as lethargy, diarrhea, and watery eyes following a challenge with lipopolysaccharide. We demonstrate here that diferuloylmethane inhibits the transmigration and infiltration of neutrophils from blood vessels to the underlying liver tissue and, hence, inhibits the damage to the tissue. Diferuloylmethane blocks the induced expression of ICAM-1 and VCAM-1 in liver and lungs. Diferuloylmethane, being a natural compound, may have few side effects and may be useful in attenuating multiple organ injury in pathological conditions arising due to excessive infiltration of neutrophils into the tissues.

Gram-negative bacteria and phagocytic cell interaction mediated by complement receptor 3

Complement receptor 3 (CR3) is an integrin that recognizes several different ligands. Binding to CR3 in phagocytic cells activates signaling pathways involved in cytoskeleton rearrangement, regulation of cell motility, alteration of gene expression and phagocytosis of complement-opsonized as well as of some non-opsonized particles and pathogenic bacteria. However, CR3-mediated phagocytosis of some Gram-negative bacteria does not induce bacterial clearance. Pseudomonas aeruginosa, Salmonella and Escherichia coli are eliminated after phagocytic cell-bacteria interaction mediated by CR3. However, Bordetella takes advantage of the CR3 function and uses it to enter into macrophages leading to bacterial survival. The final fate of the pathogen is determined by combinations of host and bacterial factors, in which molecular interactions between CR3 and bacterial ligands are involved.

The influence of methylene blue infusion on cytokine levels during severe sepsis

The aim of our study was to assess the effect of methylene blue infusion on plasma levels of cytokines in severe sepsis. In a prospective, randomized, double-blind, placebo-controlled study, patients received either methylene blue 0.5 mg.kg-1.h-1 (MB group, n = 15) or similar volume of isotonic saline (control group, n = 15) i.v. for 6 hours. Plasma concentrations of tumour necrosis factor-alpha, interleukin-1, interleukin-2 receptor, interleukin-6, interleukin-8 were measured by sensitive immunoassays at basal (15 min before start of the study), immediately after, and at 24 and 48 hours after methylene blue infusion. We evaluated haemodynamic parameters (mean arterial pressure, heart rate), blood gases, methaemoglobin levels, and biochemical parameters at the same time. Methylene blue administration had no significant effect on plasma cytokine levels, blood gases and biochemical parameters. When compared to placebo infusion in controls, methylene blue administration resulted in significantly higher mean arterial pressure (85 +/- 14 mmHg vs 74.1 +/- 10.3 mmHg; P < 0.01), and methaemoglobin levels (1.06 +/- 0.22% vs 0.9 +/- 0.05%; P < 0.05). Furthermore, comparison with baseline levels revealed significantly increased both mean arterial pressure (85 +/- 14 mmHg and 74.1 +/- 10.2 mmHg; P < 0.05) and methaemoglobin levels (1.06 +/- 0.22% and 0.88 +/- 0.06%; P < 0.05) in MB group. There was no difference in mortality rates between the groups. We found that methylene blue infusion did not change cytokine levels or outcome in severe sepsis. The administration of methylene blue, however, resulted in a transient increase in arterial pressure. Because of the limited size of the present study, and the short period of observation, our findings need to be confirmed by larger clinical trials of methylene blue infused in a dose-titrated manner.

Anticoagulant from Taraxacum platycarpum

An anticoagulant was purified from a Chinese herb, Taraxacum platycarpum. Its activity was heat-labile, and was decreased by incubation with subtilisin Carlburg or proteinase K, indicating that the active component was a protein. The protein had a molecular mass of 31 kDa by gel filtration and 33 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, so it probably was a monomer. When present at the concentration of 70, 255, and 873 nM, respectively, the protein doubled the thrombin time, prothrombin time, and activated partial thromboplastin time. It inhibited thrombin and kallikrein, but did not hydrolyze fibrinogen. The protein bound the anion-binding exosite of thrombin, competing with the fibrinogen binding site. In addition, the protein caused the murine macrophage cell line Raw 264.7 to produce cyclooxygenase-2, nitric oxide synthase, nitric oxide, and tumor necrosis factor-alpha.

Vasopressin: new uses in critical care

The science of medicine has evolved dramatically over recent years, with better understanding of the mechanisms of disease leading to innovative new treatments. However, the critical care patient still suffers from a high mortality rate with few advances from the traditional modalities of therapy. Arginine vasopressin has been explored as a vasoconstrictor in the treatment of the hypotension associated with septic shock. This drug has also recently been added to the advanced cardiac life support protocol for the resuscitation of pulseless ventricular tachycardia and ventricular fibrillation. Studies of arginine vasopressin in these situations have been promising but still have yet to prove a survival benefit over traditional therapies. Newer and larger trials are necessary to determine whether any mortality benefit can be sustained from the use of arginine vasopressin in critical care patients with septic shock and cardiac arrest secondary to pulseless ventricular tachycardia and ventricular fibrillation.

RECOMBINANT GLUCOCORTICOID INDUCED TUMOUR NECROSIS FACTOR RECEPTOR (rGITR) INDUCED COX-2 ACTIVITY IN MURINE MACROPHAGE Raw 264.7 CELLS

Stimulation of murine macrophages with recombinant soluble glucocorticoid induced tumour necrosis factor receptor (GITR) induced cyclooxygenase (COX)-2 protein and generated significant amounts of PGE(2). Previous result demonstrated that macrophages express GITR and GITR ligand constitutively. Induction of COX-2 was synergistic with interferon (INF)-gamma. GITR/ligand system could deliver an activation signal to macrophages in inflammatory processes.

Recombinant glucocorticoid induced tumor necrosis factor receptor (rGITR) induces NOS in murine macrophage

Glucocorticoid induced tumor necrosis factor receptor (GITR) is a new member of the tumor necrosis factor-nerve growth factor receptor superfamily of which the function has not been well studied. The extracellular domain of GITR was produced in Escherichia coli and purified as a single band of predicted M(r) of 18.0 kDa. GITR and GITR ligand were expressed constitutively on the surface of Raw 264.7 macrophage cell line and murine peritoneal macrophages. An extracellular domain of GITR can activate murine macrophages to express inducible nitric oxide synthase and to generate nitric oxide in a dose- and time-dependent manner.

Adrenoceptor hyporeactivity is responsible for Escherichia coli endotoxin-induced acute vascular dysfunction in humans

Impaired response to catecholamines contributes to the altered hemodynamics in sepsis, which has been attributed to excessive NO formation. We have studied the systemic hemodynamic and local forearm responses and inducible NO synthase (iNOS) expression during experimental endotoxemia in humans. Escherichia coli endotoxin (lipopolysaccharide [LPS]) was administered at doses of 1 or 2 ng/kg to healthy volunteers. In 10 subjects, the systemic pressor effect of phenylephrine was assessed before and after the administration of LPS. In 9 further subjects, forearm blood flow responses to intra-arterial noradrenaline, acetylcholine, glyceryl trinitrate, and N(G)-monomethyl-L-arginine (L-NMMA) were studied at baseline and after LPS administration. Peripheral blood was collected and analyzed for iNOS mRNA and protein. Four hours after LPS, the response of systolic blood pressure (P<0.0005) and heart rate (P<0.05) to phenylephrine was significantly reduced. In the forearm, noradrenaline-induced vasoconstriction was also reduced by approximately 50% (P<0.01), but L-NMMA responsiveness was unchanged. iNOS mRNA or protein was not increased. Marked vascular adrenoceptor hyporeactivity is detectable in the absence of increased NO activity or iNOS expression in endotoxemia, arguing against major involvement of vascular iNOS activity in the acute systemic vasodilation to LPS.

Syndecan-4 deficiency leads to high mortality of lipopolysaccharide-injected mice

Syndecan-4 is a transmembrane heparan sulfate proteoglycan belonging to the syndecan family. Following intraperitoneal injection of lipopolysaccharide (LPS), syndecan-4-deficient mice exhibited high mortality compared with wild-type controls. Severe endotoxin shock was observed in the deficient mice: systolic blood pressure and left ventricular fractional shortening were lower in the deficient mice than in the wild-type controls 9 h after LPS injection. Although histological examinations revealed no apparent differences between two groups, the plasma level of interleukin (IL)-1beta was higher in the deficient mice than in the wild-type controls 9 h after LPS injection. Consistent with the regulatory roles of syndecan-4, its expression in monocytes and endothelial cells of microvasculature increased in the wild-type mice after LPS administration. Although IL-1beta was produced to the same extent by macrophages from syndecan-4-deficient and wild-type mice after LPS stimulation, inhibition of its production by transforming growth factor-beta1 was impaired in the syndecan-4-deficient macrophages. These results indicate that syndecan-4 could be involved in prevention of endotoxin shock, at least partly through the inhibitory action of transforming growth factor-beta1 on IL-1beta production.

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.

Bacterial DNA does not increase serum corticosterone concentration or prevent increases induced by other stimuli

Bacterial DNA containing unmethylated CpG motifs (CpG DNA) and other microbial molecules such as lipopolysaccharide (LPS) have a broad range of immune stimulatory effects, which may include many shared cell signaling pathways leading to enhanced cytokine production. Some cytokines activate the hypothalamic-pituitary-adrenal (HPA) axis, and their production is downregulated by products of the HPA axis (glucocorticoids). Because such interactions have practical implications in the clinical use of CpG DNA, the present study was done to examine the effects of CpG DNA and LPS on serum corticosterone concentrations. In contrast to LPS, administration of CpG DNA (DNA from Escherichia coli) (30-300 microg) alone did not significantly increase serum corticosterone concentrations 1 or 4 h after administration. Administration of CpG DNA to mice prior to LPS caused a synergistic increase in serum tumor necrosis factor-alpha (TNF-alpha), indicative of an immune stimulatory effect. LPS and TNF-alpha, however, induced similar levels of corticosterone with or without concomitant CpG DNA. Increasing doses of LPS caused peak corticosterone levels similar to those induced by LPS in combination with CpG DNA. Exogenous TNF-alpha administered in vivo induced comparable concentrations of corticosterone with or without CpG DNA. An alternative stressor (restraint) yielded similar levels of corticosterone with or without CpG DNA. These results indicate that CpG DNA does not induce corticosterone release or alter its release by other stimuli, indicating biologically important differences in its immune effect compared to those of LPS, and possibly reduced toxicity.

Septic shock and respiratory failure in community-acquired pneumonia have different TNF polymorphism associations

Genetic factors are likely to contribute to the variable presentation of community-acquired pneumonia (CAP). The purpose of this prospective cohort study was to determine whether the LTalpha+250 (TNFbeta+250) and TNFalpha-308 gene polymorphisms are associated with different presentations of CAP. Septic shock (SS) was defined using American College of Chest Physicians/Society of Critical Care Medicine (ACCP-SCCM) criteria. Type I respiratory failure (T1RF) was defined as an O(2) saturation on room air of < 90% with a normal PCO(2). A total of 280 patients were genotyped; 31 had SS, 80 had T1RF. Genotype proportions are given in the order of AA/GA/ GG. The proportion of patients in each genotype developing SS was as follows: LTalpha+250 0.19/0.07/0.09 (p = 0.01 AA versus non-AA); TNFalpha-308 0.16/0.06/0.12 (p = NS). Carrying at least one AA (tumor necrosis factor [TNF] high secretor) genotype had an 18.0% risk of SS versus 6.8% (p = 0.006). GG homozygotes (TNF low secretors) at both loci had only a 2.9% risk of SS. Septic shock was associated with the LTalpha+250:TNFalpha-308 A:G haplotype but not the A:A haplotype, suggesting that LTalpha+250 is a marker, rather than a causative polymorphism. Carriage of the G:G haplotype had a significant protective effect against the development of septic shock (p = 0.011). T1RF was not associated with LTalpha+250 AA genotype. In the absence of septic shock, there was a significant trend to greater T1RF in patients with LTalpha+250 GG (TNFalpha hyposecretor) genotype (p = 0.03). Our finding of different genotype associations for SS and T1RF has important implications for immunotherapy in both CAP and sepsis, as well as for the definition of the systemic inflammatory response syndrome (SIRS).