UMLS:C0036690 - FACTA Search

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Query: UMLS:C0036690 (sepsis)
59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study ascertained the role of PGE2 in sepsis associated modulation of IL-2 and IL-10 production by T cells. Sepsis was induced in 225-250 g male rats (Sprague Dawley) by implanting fecal pellets containing Escherichia coli (100-150 CFU) and Bacteroides fragilis (10(4) CFU) into the abdominal cavity. Animals implanted with fecal pellets without the bacteria were designated as sterile. For the assessment of PGE2 role in sepsis, a group of septic and sterile rats were pretreated with indomethacin to inhibit endogenous PGE2 synthesis. Splenic T cells were obtained 48 h after septic or sterile implantations, and their IL-2 and IL-10 production was measured. A significant suppression in the levels of IL-2 production and mRNA expression was observed in T cells from septic rats compared with the T cells from sterile and control rats. IL-10 protein and mRNA expression was found to be significantly higher in septic rat T cell compared to sterile and control rat T cells. Although, treatment of animals with indomethacin significantly prevented the sepsis-related suppression of IL-2 production, such treatment of animals was associated with a further upregulation of IL-10 production. These data suggest that although PGE2 released during sepsis can cause T cell IL-2 down-regulation, it may not mediate the T cell IL-10 upregulation. The IL-2 down-regulation may not be an effect of IL-10 upregulation.
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PMID:Prostaglandin E2 down-regulation of T cell IL-2 production is independent of IL-10 during gram-negative sepsis. 1023 94

The isoprostanes are a group of biologically active arachidonic acid metabolites initially thought to be formed under conditions of oxidative stress and independently of cyclooxygenase. However, recent studies have demonstrated isoprostane production under conditions in which cyclooxygenase is intentionally activated/induced. Here we describe for the first time formation of isoprostanes by human vascular cells via independent pathways of oxidative stress and cyclooxygenase induction. We compared the release of the isoprostane with that of the traditional prostaglandin, prostaglandin E2. Cyclooxygenase-2 induction was confirmed by Western blot. When cells were stimulated with cytokines, the release of isoprostanes was inhibited by the cyclooxygenase-1 and -2 inhibitor indomethacin as well by as the cyclooxygenase-2 selective inhibitor L-745,337. However, treatment of cells with the superoxide-producing enzyme xanthine oxidase also resulted in isoprostane release, which was not affected by cyclooxygenase inhibition, unlike PGE2 release under the same condition. Thus, two independent pathways relating to oxidative stress and cyclooxygenase-2 induction form isoprostanes. These findings may have particular importance in diseases such as sepsis and ARDS in which oxidant stress occurs and cyclooxygenase is induced.
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PMID:Isoprostanes and PGE2 production in human isolated pulmonary artery smooth muscle cells: concomitant and differential release. 1033 84

The pathogenesis of septicemia can be triggered by LPS, a potent stimulus for PG synthesis. The enzyme cyclooxygenase (COX) is a rate-limiting step in PG production. COX exists as two isoforms: COX-1, which is constitutively expressed in most cell types, and COX-2, which is inducible by LPS and cytokines in a variety of cells. In this study we determined the role of the proinflammatory cytokines IL-1 beta and TNF-alpha released by LPS-stimulated U937 human macrophages in the regulation of COX-2. Macrophages exposed to LPS showed a rapid and sustained expression of COX-2 mRNA and protein for up to 48 h, whereas PGE2 production was notably enhanced only after 12 h. LPS increased COX-2 gene transcription and activation of the transcription factor NF-kappa B in a transient manner. LPS-treated macrophages produced high levels of TNF-alpha and moderate amounts of IL-1 beta protein. However, neutralizing Abs against these cytokines had no effect on COX-2 mRNA and protein expression, nor did they affect the stability of COX-2 mRNA. Interestingly, in the presence of LPS or exogenous IL-1 beta, COX-2 transcripts were stabilized, and actinomycin D inhibited their degradation. Only when LPS or IL-1 beta was removed did COX-2 mRNA decay with a t1/2 of >/=5 h. In contrast, dexamethasone promoted a faster decay of the LPS-induced COX-2 transcripts (t1/2 = 2.5 h). These results clearly demonstrate that LPS can regulate COX-2 at both transcriptional and posttranscriptional levels independently from endogenous IL-1 beta and TNF-alpha in human macrophages.
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PMID:Lipopolysaccharide modulates cyclooxygenase-2 transcriptionally and posttranscriptionally in human macrophages independently from endogenous IL-1 beta and TNF-alpha. 1039 93

Major surgery, multiple injury, and severe sepsis lead to an impaired immune response. The suppressed status of the immune system is reflected by a reduced TNFalpha production of whole blood after stimulation with endotoxin in vitro and by a decreased HLA-DR expression on monocytes. In the present study, the effect of the immunostimulating hematopoetic growth factor GM-CSF on whole blood cultures of multiple injury, cardiac surgery, and severe sepsis patients was investigated. Endotoxin-induced TNFalpha production and HLA-DR expression was reduced in blood cultures of these patients compared to healthy donors. Preincubation with GM-CSF in vitro increased cytokine production in volunteers' and all patients' blood specimens in a dose-dependent manner. The elevation of cytokine response in cardiopulmonary bypass patients' blood, caused by in vitro preincubation with GM-CSF, equaled that of normal patients, whereas GM-CSF caused a lower rise of TNFalpha-producing capacity in blood of multiple-injury and sepsis patients. Further, GM-CSF treatment in vitro increased the down-regulated HLA-DR expression on monocytes prepared after cardiac surgery to a degree comparable to preoperative levels. Finally, GM-CSF incubation in vitro elevated TNFalpha synthesis in normal monocytes and in cells treated with a combination of the anti-inflammatory mediators IL-10, TGFbeta, and PGE2. These experiments show that hyporesponsiveness of whole blood induced by trauma, sepsis, or cardiac surgery is not irreversible but can be, at least in vitro, overridden by the immunostimulating compound GM-CSF.
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PMID:Influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) on whole blood endotoxin responsiveness following trauma, cardiopulmonary bypass, and severe sepsis. 1046 47

PGE2-mediated suppression of T cell proliferation during sepsis could result from altered Ca2+ signaling. The present study evaluated the effects of PGE2 on Ca2+ release from intracellular stores and its influx through the plasma membrane in splenic T cells from Sprague-Dawley rats. Intracellular Ca2+ concentration ([Ca2+]i) responses in individual T cells were assessed using the Ca2+ imaging technique, and the release of Ca2+ from intracellular stores and Ca2+ influx were spectrofluorometrically quantified in T cell suspensions. Under unstimulated conditions, nearly 85% of T cells exhibited [Ca2+]i </=50 nM. After stimulation with concanavalin A (Con A), an increase in [Ca2+]i was recorded in approximately 60% of the cells. The pretreatment of T cells with PGE2 had no apparent effect on [Ca2+]i in resting cells; it significantly suppressed the Con A-induced increase in [Ca2+]i in all of the Con A-responsive cells. Ca2+ release from the intracellular stores contributed to the early spike in [Ca2+]i, and the late phase of elevation in [Ca2+]i was dependent on Ca2+ influx through the plasma membrane. Our data suggest that PGE(2) causes an overall suppression of the Con A-induced [Ca2+]i elevation in T cells via inhibiting both Ca2+ influx and its release from the intracellular stores.
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PMID:PGE2 suppresses mitogen-induced Ca2+ mobilization in T cells. 1060 Sep 22

Prostaglandin E2 production by tissue-fixed macrophages (Mphi) after severe injury contributes to an enhanced susceptibility to infection and sepsis. The purpose of this study was to investigate the effect of cyclic adenosine monophosphate (cAMP) on prostaglandin (PGE2) production and cyclooxygenase II (COX-2) gene activation in LPS-stimulated macrophages (Mphi). RAW264.7 cells, a mouse Mphi cell line, were exposed to various concentrations of dibutyryl cAMP +/- lipopolysaccharide (10 microg/mL) stimulation. Total Mphi ribonucleic acid (RNA) was harvested for the determination of COX-2 messenger RNA (mRNA) with mouse complementary deoxyribonucleic acid (cDNA) by Northern blot assay. Mphi supernatant was collected for the measurement of tumor necrosis factor (TNF) by L929 bioassay and PGE2 by enzyme-linked immunosorbent assay (ELISA), respectively. Mphi NFkappaB activity was determined by electrophoretic mobility shift assays (EMSA). Dibutyryl cAMP significantly inhibited TNF production by LPS-stimulated Mphi. Dibutyryl cAMP (1 mM) alone induced PGE2 production. Dibutyryl cAMP (100 microM and 1 mM) also augmented PGE2 production by LPS-stimulated Mphi. Dibutyryl cAMP had similar effect on Mphi COX-2 mRNA expression and NFkappaB activity. Our data demonstrate that cAMP modulates Mphi TNF production and upregulates COX-2 gene and PGE2 production.
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PMID:Cyclooxygenase 2 (COX-2) gene activation is regulated by cyclic adenosine monophosphate. 1063 68

The production and release of granulocytes and macrophages, crucial elements of the host defense system, are significantly impaired after burn injury and sepsis. Prostaglandin E2 (PGE2) is known to be myelosuppressive. We hypothesized that the macrophages contributed to myelopoietic suppression by means of increased PGE2 production, which is induced by thermal injury and sepsis. In this study, peritoneal macrophages were elicited at day 3 from normal mice and from mice who underwent a 15% total body surface area dorsal scald burn with or without Pseudomonas aeruginosa burn wound infection. The macrophages were incubated with or without endotoxin and with or without PGE2 polyclonal antiserum (anti-PGE2) for 18 hours. Macrophage supernatants were then used in co-cultures of bone marrow cells in a clonogenic assay of granulocyte-macrophage colony-forming cells (GM-CFCs) to determine the effect of burn wound infection on the alteration of the proliferative status of the GM-CFCs. Burn wound infection and endotoxin both caused marked reductions in GM-CFC growth in culture (20%-40% as compared with normal, P < .05-.01). The inhibition of GM-CFC growth induced by burn, burn plus infection, or endotoxin was significantly reversed by the addition of anti-PGE2 to the cultures (30%-40% increase in GM-CFC colony growth as compared with cultures without anti-PGE2). These results suggest that PGE2 is a key mediator in the gram-negative sepsis-induced macrophage suppression of granulocyte and macrophage production. The ability of anti-PGE2 to neutralize PGE2 activity may provide a useful means of mitigating myeloid depression that follows postburn sepsis.
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PMID:Macrophage mediated suppression of granulocyte and macrophage growth after burn wound infection reversal by means of anti-PGE2. 1066 41

This study examined effects of trauma and sepsis on Kupffer cell function. When CBA/J mice had femur fracture (FFx), no deaths occurred. After cecal ligation and puncture (CLP), 44% died. Following combined injuries (FFx + CLP), mortality increased to 60%, suggesting a deleterious effect between FFx + CLP. Kupffer cell ablation with GdCI3 decreased mortality to 13% after CLP and 5% after FFx + CLP. After FFx, CLP, and FFx + CLP, Kupffer cells isolated from Sprague-Dawley rats produced 720%, 1,100%, and 2,130% more O2. than sham, respectively. Phagocytosis increased 320%, 610%, and 150%. Kupffer cell PGE2 production also increased 300%, 510%, and 300% over sham. After FFx alone, TNF-alpha production decreased 40%. By contrast, CLP and FFx + CLP increased TNF-alpha release 25% and 100%, respectively. After FFx, NO. production decreased 44%, whereas NO increased 280% and 260% after CLP and FFx + CLP. These findings indicate that Kupffer cells mediate mortality after CLP and FFx + CLP. Increased mortality is associated with a more proinflammatory and less antimicrobial Kupffer cell phenotype.
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PMID:Proinflammatory kupffer cell alterations after femur fracture trauma and sepsis in rats. 1109 89

Recent studies suggest that increased activation-induced lymphocyte apoptosis (AICD) is detected in mouse splenocytes during polymicrobial sepsis which may contribute to lymphocyte immune dysfunction [i.e., decreased interleukin (IL-)2 and interferon-gamma (IFN-gamma) production] leading to the associated morbidity seen in those animals. Thus, we wanted to examine the hypothesis that immune suppressive agents, such as IL-4, IL-10 or prostaglandin E2(PGE2), known to be elevated in septic animals, also contribute to this increase in AICD. Here we demonstrate that the inclusion of monoclonal antibody (mAb) to IL-10, but not anti-IL-4 or ibuprofen (IBU), blunted this sepsis induced increase in splenocyte AICD. Additionally, septic mice deficient in the IL-10 gene product (-/-) showed neither an increase in AICD nor a loss of IL-2/IFN-gamma release capacity. Interestingly, mAb to IL-10 did not altered the extent of AICD in a Th2-cell line, but exogenous IL-10 did potentiate Th1-like cell line AICD. This was consistent with the finding that the increased AICD seen in septic mouse splenocytes was restricted largely to the CD4+ cells producing IL-2 (Th1-cells) and that mAb to IL-10 treatment suppressed this change. Furthermore, IL-10 appears to mediate its AICD effect by upregulation of the Fas receptor and Fas receptor signaling protein components, but not by altered expression of Bcl/Bax/Bad family members, in septic mouse splenocytes. To the extent that these processes contribute in a pathological fashion to the animal's capacity to survive sepsis we have previously observed that in vivo post-treatment of mice with mAb IL-10 markedly attenuated septic mortality. Collectively, these data indicate that in the septic mouse the Th2 cytokine IL-10 not only serves to actively induce Th1 lymphocyte immune dysfunction but also plays a role in their apoptotic depletion. These processes in turn appear to contribute to the animal's inability to ward off lethal septic challenge.
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PMID:IL-10 mediation of activation-induced TH1 cell apoptosis and lymphoid dysfunction in polymicrobial sepsis. 1129 91

Studies indicate that trauma-hemorrhage results in activation of Kupffer cells to release inflammatory mediators and it leads to immunosuppression and increased susceptibility to subsequent sepsis. The cyclooxygenase (COX) product prostaglandin (PG) E2 appears to be central to this process, however, non-selective inhibition of COX activity with non-steroidal anti-inflammatory agents that block both the constitutive (COX-1) and inducible (COX-2) isoforms of cyclooxygenase has not yielded promising results in trauma patients. Nonetheless, it remains unknown whether selective inhibition of COX-2 activity has any salutary effect following trauma-hemorrhage and subsequent induction of sepsis. To study this, male C3H/HeN mice were subjected to laparotomy (i.e., soft-tissue trauma) and hemorrhagic shock (35 +/- 5 mmHg for 90 min, then resuscitated) or to sham operation. Twenty-four hours later, the mice were subjected to sepsis by cecal ligation and puncture (CLP) or to sham CLP. The mice were treated with the COX-2 inhibitor NS-398 (10 mg/kg body weight, intraperitoneally) or vehicle immediately after trauma-hemorrhage or sham operation, 12 h thereafter, and following CLP or sham CLP. At 5 h after CLP, plasma PGE2, Interleukin-(IL) 6, and TNF-alpha levels were determined along with Kupffer cell IL-6 and TNF-alpha production in vitro. NS-398 treatment markedly suppressed the elevation in plasma PGE2 levels following CLP. The increase in plasma IL-6 levels after CLP were also significantly attenuated by NS-398 treatment. In vitro Kupffer cell IL-6 production after CLP was significantly reduced by in vivo NS-398 treatment. However, NS-398 had no effect on TNF-alpha levels, in vivo and in vitro. These findings indicate that activation of COX-2 following trauma-hemorrhage and subsequent sepsis up-regulates Kupffer cell IL-6 production. Thus, selective inhibition of COX-2 activity may reduce the deleterious consequences of sepsis under such conditions.
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PMID:Cyclooxygenase-2-mediated regulation of Kupffer cell interleukin-6 production following trauma-hemorrhage and subsequent sepsis. 1177 48

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