Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A relationship between physiological parameters of severe sepsis and immunological function has not been established. In ten severely ill patients with sepsis physiological risk was assessed by the Acute Physiology and Chronic Health Evaluation (APACHE) III score, while one component of immunological function was evaluated using peripheral blood mononuclear cell (PBMC) cytokine production after stimulation with lipopolysaccharide (LPS) in vitro. Five of the ten patients died. Mean (s.e.m.) APACHE III scores at admission were not significantly different between survivors and non-survivors (82(13) versus 95(13)) but after 72 h they were lower in survivors (51(13) versus 111(15), P < 0.05). Downregulation of cytokine production by PBMC on LPS stimulation was a transient event in survivors. Survivors had a three-fold increase in tumour necrosis factor alpha bioactivity within 72 h, but there was no increase in non-survivors. A similar pattern was demonstrated for interleukin (IL) 1 beta (P < 0.05 between survivors and non-survivors) and IL-6 (P = 0.06) immunoactivity. Physiological as well as immunological parameters in critically ill patients with sepsis independently predicted hospital survival (r2 = 0.2). These data demonstrate a relationship between the pattern of cytokine production in vitro and survival.
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PMID:Correlation between Acute Physiology and Chronic Health Evaluation (APACHE) III score and immunological parameters in critically ill patients with sepsis. 898 40

Leukemia inhibitory factor (LIF), a pleiotropic cytokine with many biologic effects overlapping with those of IL-6, has been implicated in the pathogenesis of sepsis. We here analyzed the kinetics of LIF in 13 baboons challenged with a lethal (n=6) or sublethal (n=7) dose of Escherichia coli. In addition, to assess the role of TNF-alpha in the induction of LIF in vivo, seven baboons were studied that had either received a bolus injection of recombinant human TNF-alpha (100 micrograms/kg, n=3), or to whom 15 mg/kg of an anti-TNF mAB before lethal E. coli challenge was administered (n=4). LIF levels increased 2 h after E coli challenge, and reached maximum values at 4 and 8 h after a sublethal (4.4 +/- 1.6 ng/ml) or lethal (40.9 +/- 3.8 ng/ml) dose, respectively. TNF-alpha injection induced a modest rise in LIF concentrations, peaking after 6 h (228 +/- 46 pg/ml). Circulating LIF correlated with plasma levels of IL-6, both after E. coli challenge (Spearman Rank coefficient of correlation (r) = 0.849, p<0.001), as well as upon TNF-alpha injection (r=0.863, p<0.001). Moreover, the E. coli-induced release of either cytokine was reduced 6- to 10-fold after pretreatment with anti-TNF mAb, except in one nonsurviving animal, which exhibited a progressive increase of LIF and IL-6 levels despite the absence of TNF immunoreactivity. These results show that TNF-alpha is an intermediate factor in concerted release of LIF and IL-6 in vivo, and indicate that the enhanced elaboration of these cytokines may predict disease outcome in severe sepsis.
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PMID:Release of leukemia inhibitory factor in primate sepsis. Analysis of the role of TNF-alpha. 866 13

Acute-phase reactants (APRs) are proteins synthesized in the liver following induction by interleukin-1 (IL-1), IL-6, and glucocorticoids, involving transcriptional gene activation. Lipopolysaccharide-binding protein (LBP) is a recently identified hepatic secretory protein potentially involved in the pathogenesis of sepsis, capable of binding the bacterial cell wall product endotoxin and directing it to its cellular receptor, CD14. In order to examine the transcriptional induction mechanisms by which the LBP gene is activated, we have investigated the regulation of expression of its mRNA in vitro and in vivo as well as the organization of 5' upstream regulatory DNA sequences. We show that induction of LBP expression is transcriptionally regulated and is dependent on stimulation with IL-1beta, IL-6, and dexamethasone. By definition, LBP thus has to be viewed as a class 1 acute-phase protein and represents the first APR identified which is capable of detecting pathogenic bacteria. Furthermore, cloning of the LBP promoter revealed the presence of regulatory elements, including the common APR promoter motif APRE/STAT-3 (acute-phase response element/signal transducer and activator of transcription 3). Luciferase reporter gene assays utilizing LBP promoter truncation and point mutation variants indicated that transcriptional activation of the LBP gene required a functional APRE/STAT-3 binding site downstream of the transcription start site, as well as an AP-1 and a C/EBP (CCAAT enhancer-binding protein) binding site. Gel retardation and supershift assays confirmed that upon cytokine stimulation APRF/STAT-3 binds to its recognition site, leading to strong activation of the LBP gene. Unraveling of the mechanism of transcriptional activation of the LBP gene, involving three known transcription factors, may contribute to our understanding of the acute-phase response and the pathophysiology of sepsis and septic shock.
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PMID:The lipopolysaccharide-binding protein is a secretory class 1 acute-phase protein whose gene is transcriptionally activated by APRF/STAT/3 and other cytokine-inducible nuclear proteins. 866 65

Proinflammatory cytokines are important mediators during endotoxemia. In experimental models, injection of lipopolysaccharide (LPS) activates macrophages leading to excessive secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta and IL-6; infusion of high dose of these mediators results in organ failure and death. Natural infection may be different, because it persists over days or even weeks, with repeated endotoxin challenge to macrophages. Little is known about the capacity of peripheral blood mononuclear cells (PBMCs) to release proinflammatory cytokines under these conditions. Therefore, as an ex vivo model of sepsis, the expression of proinflammatory cytokines after stimulation of whole blood with LPS was studied. A high LPS dose (1 microgram/ml) maximally increased TNF-alpha, IL-1 beta and IL-6 secretion in controls, but a marked depression was observed in septic patients (p < 0.01; 15 patients with severe sepsis versus 20 control patients without infection). This reduction persisted for up to 10 days after diagnosis of sepsis. The release of TNF-alpha, IL-1 beta and IL-6 was markedly decreased in the septic group even when a lower and physiologically more relevant LPS concentration (1 ng/ml) was used. IL-1 beta mRNA was similar to controls, but a down-regulation was observed in TNF-alpha and IL-6 transcript levels in PBMCs from the blood of septic patients. This was at least in part due to a marked reduction in TNF and IL-6 mRNA half-life. These results indicate that different mechanisms down-regulate proinflammatory cytokine release in the whole blood of septic patients. Although excessive secretion is known to be deleterious, low concentrations of these cytokines are involved in regulating essential cellular and humoral immune functions. Thus, the reduced capacity to express and release adequate amounts of proinflammatory cytokines after exposure to endotoxin, as observed in whole-blood PBMCs from septic patients, may contribute to the development of immunodeficiency.
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PMID:Interleukin-1, -6 and tumor necrosis factor-alpha release is down-regulated in whole blood from septic patients. 867 54

The immune and endocrine mediators that are released during sepsis (e.g., tumor necrosis factor [TNF] alpha, interleukin [IL]-1, IL-6, transforming growth factor [TGF] beta, prostaglandin [PG] E2, catecholamines, vasopressin, glucagon, insulin, and glucocorticoids) can produce inappropriate detrimental cellular responses contributing to exacerbation of septic injury. Examples of such sepsis-related inappropriate responses are: exaggerated hepatic acute-phase protein (APP) expression and release skeletal muscle insulin resistance, and suppressed T-lymphocyte proliferation. The studies discussed in this article present evidence that the generation of the sepsis-related hepatic, skeletal muscle, and T-lymphocyte responses emanate from alterations in intracellular Ca2+ (Ca2+i) homeostasis. In hepatocytes, there is indication of a sepsis-mediated increase in Ca2+ influx from the extracellular milieu leading to a sustained increase in the apparent resting cell Ca2+i concentration ([Ca2+]i) and its depressed elevation on stimulation with Ca2+-mobilizing hormones such as catecholamines and vasopressin. These Ca(2+)- related changes can affect not only the signaling pathways in which Ca2+i itself serves as a signaling component, but also the signaling systems turned on by other sepsis-induced agonists which may not be dependent on Ca2+ signaling. TGF-beta, IL-1, TNF alpha, and IL-6 activate a primarily protein kinase C (PKC)-dependent intracellular signal system for the elicitation of a normal hepatic APP response (APPR). The increased apparent basal [Ca2+]i in sepsis can hypersensitize PKC activation and thus lead to an exaggerated APPR. In the skeletal muscle, an evident increase in Ca2+ membrane flux during sepsis pointed to an increase in the basal [Ca2+]i resulting from a plausible cytokine-mediated overactivation of the voltage-sensitive Ca2+ channels. The increased basal [Ca2+]i can negatively modulate the insulin-mediated stimulation of GLUT4-dependent glucose transport despite the possibility that Ca2+i might not participate as a component in the insulin-receptor-regulated signaling pathway. Increased [Ca2+]i in skeletal myocytes can either directly promote the phosphorylation of GLUT4 or prevent its dephosphorylation, both of which effectively block insulin stimulation of glucose uptake, thereby contributing to insulin resistance. In T lymphocytes, septic injury appears to induce an attenuation in the mitogen and, thus, presumably a T-cell antigen receptor (TCR)-mediated elevation in [Ca2+]i without affecting the basal [Ca2+]i. This decrease in TCR-related Ca2+i mobilization evidently contributes to the suppression of T lymphocyte proliferation during sepsis, probably via an in vivo action of prostaglandin (PG) E2 on the T cells during sepsis. The blockade of PGE2 production after indomethacin administration to septic animals prevents alterations in both T-cell Ca2+i mobilization and proliferation. PGE2 probably acts through its second messenger, cyclic adenosine 3'5'-monophosphate, which can antagonize Ca2+i signaling in T cells.
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PMID:Alterations in calcium signaling and cellular responses in septic injury. 868 77

Fusion proteins of the human 55-kDa TNF receptor extracellular domain with hinge and C2/C3 constant domains of human IgG1 or IgG3 heavy chains were tested in a primate sepsis model. Twenty-four baboons received 4.6, or 0.2 mg/kg of TNFR5-G1,3, or placebo, before the administration of a lethal dose of live Escherichia coli. Treatment with TNFR5-G1,3 decreased 5-day mortality from 88% in the placebo group to 12% in the TNFR5-G1,3-treated animals (p < 0.01 by Fisher's exact test). Treatments with TNR5-G1 and TNFR5-G3 in doses from 0.2 to 4.6 mg/kg were efficacious. Free plasma TNF was neutralized by all treatments, but inactive TNF/TNFR5-G1,3 complexes remained in circulation for prolonged periods. TNFR5-1,3 treatments attenuated the hemodynamic disturbances, reduced fluid requirements, and decreased the systemic IL-1 beta, IL-6, and IL-8 responses. In addition, TNFR5-G1,3 treatment shortened the granulocytopenia and reduced the loss of cellular TNF receptors from granulocytes. The decrease in fibrinogen concentrations and increase in prothrombin and partial thromboplastin times were significantly attenuated by TNFR5-G1,3 treatment. TNFR5-G1,3 treatment markedly attenuated the rise in plasma lactate concentration. Histologic studies of TNFR5-G1,3 revealed dose-dependent protection against tissue injury by Escherichia coli administration.
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PMID:Protection against lethal Escherichia coli bacteremia in baboons (Papio anubis) by pretreatment with a 55-kDa TNF receptor (CD120a)-Ig fusion protein, Ro 45-2081. 869 Sep 12

Phagocytic cells, such as polymorphonuclear neutrophils, monocytes, and macrophages, are essential for defense against infection caused by a variety of microorganisms. The mechanisms used by these cells to destroy microbes comprise a potent oxidative armamentarium including superoxide, hydrogen peroxide, and hypochlorous acid. In addition, granule contents such as proteolytic enzymes, lysozyme, lactoferrin, and myeloperoxidase are released into the phagosome to destroy ingested microorganisms. Inflammatory cytokines, such as tumor necrosis factor (TNF), interleukin-1 (IL-1), and IL-6, enhance the phagocytic and microbicidal activity of the cells and increase their stickiness. It has been demonstrated in a variety of animal and clinical studies that activated phagocytes can damage the host they are designed to protect, using the mechanisms described above. Alkylxanthines, including pentoxifylline, are potent inhibitors of this inflammatory damage by two major actions: (a) reduction of the production of inflammatory cytokines (especially TNF) by phagocytes stimulated with a variety of microbial products (e.g., endotoxin); and (b) reversal of the effect of these cytokines on phagocytes. Thus, pentoxifylline counteracts the following effects of inflammatory cytokines on phagocytes: increased adherence, shape change resulting in larger size and rigidity, increased oxidative burst, priming for an enhanced oxidative burst, increased degranulation, and decreased chemotactic movement. In addition, these activities synergize with the normal anti-inflammatory mediator adenosine. Alkylxanthines have the potential to be effective therapy for conditions in which inflammatory cytokines and phagocytes cause damage, including the sepsis syndrome, ARDS, AIDS, and arthritis.
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PMID:Cytokines, phagocytes, and pentoxifylline. 869 56

Sepsis is a constellation of clinical signs and symptoms resulting from excessive systemic host inflammatory response to infection. This inflammatory response is largely mediated by cytokines, which are released into the systemic circulation. Plasma concentrations of specific cytokines, TNF alpha, IL-1 beta, IL-6 and IL-8 are frequently elevated in human sepsis and cytokine concentrations correlate with severity and outcome of sepsis. In addition to pro-inflammatory cytokines, soluble cytokine receptors, cytokine receptor antagonists and counter-inflammatory cytokines are also produced in large quantities in patients with sepsis; however, the specific role of these molecules in sepsis remains undefined. A complex interaction of cytokines and cytokine-neutralizing molecules probably determines the clinical presentation and course of sepsis. Intervening in this sequence of events to modify the host inflammatory responses may prove to be a beneficial treatment strategy for sepsis, but currently tested anticytokine therapies have been largely unsuccessful.
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PMID:Sepsis and cytokines: current status. 870 20

The immune response to trauma, shock, and/or sepsis appears to exhibit a bimodal response, in which there is an early exaggerated inflammatory response, giving way over time to a state of hyporesponsiveness or immune dysfunction. This state of immune dysfunction is frequently associated with increased infectious complications and/or mortality, seen following shock or trauma. In this article, we present an overview of some of those changes that have been seen with respect to the process of major histocompatibility class II (MHC class II) antigen presentation by macrophage, a key component of the overall host immune response to foreign bacterial and/or fungal pathogens encountered following shock/trauma (with a particular emphasis on hemorrhagic shock as a component of traumatic shock). With respect to the overall process of antigen presentation, defects (dysfunction) are evident not only in models of shock and sepsis, but also in traumatized patients. Studies of the capacity of a monocyte's/macrophage's ability to present antigen indicate that defects can be detected, not only in those steps involved in antigenic processing, but also in MHC class II molecule expression and accessory molecule function (or its inhibition) following shock. Those changes in the macrophage's capacity to process antigen seen during the first 24 h after hemorrhagic shock appear to be associated with the cell's metabolic response to regional hypoxia and/or the shift to proinflammatory mediator release (tumor necrosis factor, interleukin [IL]-1, IL-6, etc.). This initial acute response to shock appears to act as the nidus for chronic anti-inflammatory mediator release (prostaglandin E2, transforming growth factor-beta, IL-10, IL-4, nitric oxide, etc.), which may mediate the sustained depression of the antigen-presenting cell's function.
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PMID:Trauma-induced suppression of antigen presentation and expression of major histocompatibility class II antigen complex in leukocytes. 870 94

The use of antibody therapy for the treatment of infections and inflammatory disease is well established. Unfortunately, clinical studies of antiendotoxin and anti-TNF monoclonal antibodies have failed to show clear physiological or survival benefit. Little information is available regarding the effect of antibodies to cytokines other than TNF in human sepsis. Limited pre-clinical data indicate that IL-6 antibodies may abrogate the effects of endotoxin infusion, but no human studies have been performed. Although both monoclonal and polyclonal antibodies have the potential to protect septic humans, at this time it is the polyclonal antibodies that have shown the greatest promise. Each type of antibody possesses specific advantages and limitations, the ultimate effectiveness of which will need to be proven in large randomized clinical trials.
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PMID:Applications of molecular biology and biotechnology: antibody therapy of sepsis. 872 29


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