UMLS:C0243026 - FACTA Search

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Query: UMLS:C0243026 (sepsis)
52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The extrinsic hypercoagulation often resulting from sepsis could contribute to disseminated intravascular coagulation and cardiovascular complications. The effective prevention and intervention remained largely complex and unclear. In a cell model of human leukemia THP-1 monocytes following bacterial endotoxin (LPS) exposure, we show the novel anticoagulant ability of polyamino acid (polyAA) to suppress the extrinsic hypercoagulation. LPS-induced monocytic tissue factor (mTF) procoagulation was readily offset by poly-L-lysine (PLK), poly-L-arginine (PLR), or poly-L-ornithine (POR) included in single-stage clotting assays. IC50 was estimated at 0.35, 0.30, or 0.58 microM for PLR, POR, or PLK, respectively, whereas, poly-L-asparatic acid (PLD) remained ineffective. In a separate approach, inclusion of cationic polyAA in human plasma significantly prolonged prothrombin time, confirming the depressed extrinsic coagulation. In chromogenic assays dissecting the extrinsic pathway, we further determined the inhibitory site(s). PLK, PLR, or POR significantly inhibited LPS-induced FVII activation, which was consistent with the diminished FVIIa formation shown on Western blotting analysis. In contrast, polyAA did not show any additional effect on either FVIIa/FXa amidolytic activities or mTF/FVIIa-catalyzed FX activation. Nor did polyAA show any effect on FVII activation directly catalyzed by FXa. Taken together, PLK, PLR, or POR preferentially inhibited mTF-dependent FVII activation, accounting for their novel anticoagulant activities. PolyAA might present the specific antagonists to arrest the extrinsic hypercoagulation following inflammation.
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PMID:Novel anticoagulant activity of polyamino acid offsets bacterial endotoxin-induced extrinsic hypercoagulation: downregulation of monocytic tissue factor-dependent FVII activation. 1450 32

While moderate hypothermia is protective against ischemic cardiac and brain injury, it is associated with much higher mortality in patients with sepsis. We previously showed that in vitro exposure to moderate hypothermia (32 degrees C) delays the induction and prolongs the duration of TNF-alpha and IL-1beta secretion by lipopolysaccharide (LPS)-stimulated human mononuclear phagocytes. In the present study, we extended these observations by showing that moderate hypothermia exerts effects on TNF-alpha and IL-1beta generation in the human THP-1 monocyte cell line that are similar to those that we previously found in primary cultured monocytes; that hypothermia causes comparable changes in cytokine generation stimulated by zymosan, toxic shock syndrome toxin-1, and LPS; and that hypothermia causes similar changes in TNF-alpha and IL-1beta mRNA accumulation. TNF-alpha mRNA half-life, determined after transcriptional arrest with actinomycin D, was not significantly prolonged by lowering incubation temperature from 37 to 32 degrees C, suggesting that hypothermia modifies TNF-alpha gene transcription. This finding was further supported by reporter gene studies showing a threefold increase in activity of the human TNF-alpha promoter at 32 vs. 37 degrees C. Electrophoretic mobility shift assay revealed that hypothermia prolonged NF-kappaBeta activation, identifying a potential role for this transcription factor in mediating the effects of hypothermia on TNF-alpha and IL-1beta production. Delayed reexpression of the inhibitor IkappaBalpha, shown by Northern blotting and immunoblotting, may account in part for the prolonged NF-kappaBeta activation at 32 degrees C. Augmentation of NF-kappaBeta-dependent gene expression during prolonged exposure to hypothermia may be a common mechanism leading to increased lethality in sepsis, late-onset systemic inflammatory response syndrome after accidental hypothermia, and neuroprotection after ischemia.
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PMID:Hypothermia prolongs activation of NF-kappaB and augments generation of inflammatory cytokines. 1507 Aug 15

Several lines of evidence have implicated activated protein C (APC) to be an endogenous inhibitor of the inflammatory septic cascade. APC may exhibit direct anti-inflammatory properties, independent of its antithrombotic effects. Chemokines influence the interaction of monocytes at the endothelium during infection and sepsis and are involved in the molecular events leading to an adverse and lethal outcome of sepsis. Defining regulatory mechanisms on the monocytic release profile of the proinflammatory C-C chemokines macrophage inflammatory protein-1-alpha (MIP-1-alpha) and monocyte chemoattractant protein-1 (MCP-1) might have therapeutic implications for the treatment of sepsis. We established a monocytic cell model of inflammation by the addition of lipopolysaccharide (LPS) and examined the effect of human APC on LPS-stimulated chemokine release from the monocytic cell line THP-1. We found that human APC in supra-physiological concentrations of 2.5-10 microg/ml inhibited the LPS-induced release of the chemokines MIP-1-alpha and MCP-1, as measured by enzyme-linked immunosorbent assays (ELISA) at 6 up to 24 h. In addition to experiments on THP-1 cells, recombinant human APC in concentrations of 50 ng/ml was found to have an inhibiting effect on the release of MIP-1-alpha from freshly isolated mononuclear cells of septic patients. The ability of APC to decrease the release of the C-C chemokine MIP-1-alpha from the monocytic cell line THP-1 and from human monocytes may identify a novel immunomodulatory pathway by which APC exerts its anti-inflammatory action and may contribute to control the inflammatory response in sepsis.
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PMID:Activated protein C inhibits the release of macrophage inflammatory protein-1-alpha from THP-1 cells and from human monocytes. 1513 4

LPS pretreatment of human pro-monocytic THP-1 cells induces tolerance to secondary LPS stimulation with reduced TNFalpha production. However, secondary stimulation with heat-killed Staphylococcus aureus (HKSa) induces priming as evidenced by augmented TNFalpha production. The pro-inflammatory cytokine, IFNgamma, also abolishes suppression of TNFalpha in LPS tolerance. The effect of LPS tolerance on HKSa and IFNgamma-induced inflammatory mediator production is not well defined. We hypothesized that LPS, HKSa and IFNgamma differentially regulate pro-inflammatory mediators and chemokine production in LPS-induced tolerance. THP-1 cells were pretreated for 24 h with LPS (100 ng/ml) or LPS (100 ng/ml) + IFNgamma (1 microg/ml). Cells were subsequently stimulated with LPS or HKSa (10 microg/ml) for 24 h. The production of the cytokines TNFalpha, IL-6, IL-1beta, and GMCSF and the chemokine IL-8 were measured in supernatants. LPS and HKSa stimulated TNFalpha (3070 +/- 711 pg/ml and 217 +/- 9 pg/ml, respectively) and IL-6 (237 +/- 8.9 pg/ml and 56.2 +/- 2.9 pg/ml, p < 0.05, n = 3, respectively) in control cells compared to basal levels (< 25 pg/ml). LPS induced tolerance to secondary LPS stimulation as evidenced by a 90% (p < 0.05, n = 3) reduction in TNFalpha. However, LPS pretreatment induced priming to HKSa as demonstrated by increased TNFalpha (2.7 fold, from 217 to 580 pg/ml, p < 0.05, n = 3 ). In contrast to suppressed TNFalpha, IL-6 production was augmented to secondary LPS stimulation (9 fold, from 237 to 2076 pg/ml, p < 0.01, n = 3) and also primed to HKSa stimulation (62 fold, from 56 to 3470 pg/ml, p < 0.01, n = 3). LPS induced IL-8 production and to a lesser extent IL-1beta and GMCSF. LPS pretreatment did not affect secondary LPS stimulated IL-8 or IL-1beta, although HKSa stimulation augmented both mediators. In addition, IFNgamma pretreatment reversed LPS tolerance as evidenced by increased TNFalpha levels while IL-6, IL-1beta, and GMCSF levels were further augmented. However, IL-8 production was not affected by IFNgamma. These data support our hypothesis of differential regulation of cytokines and chemokines in gram-negative- and gram-positive-induced inflammatory events. Such changes may have implications in the pathogenesis of polymicrobial sepsis.
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PMID:Differential regulation of cytokine and chemokine production in lipopolysaccharide-induced tolerance and priming. 1515 97

Oxidative stress during sepsis induces tissue damage, leading to organ dysfunction and high mortality. The antioxidant effects of vitamin E have been reported in several diseases, but not in sepsis. Statins have cholesterol-independent anti-inflammatory effects that are related to a decrease of isoprenoid proteins and oxidative stress. Therefore, we evaluated superoxide anion (O2- degree) production and ex vivo effects of vitamin E and simvastatin in sepsis. Fourteen healthy volunteers, 14 intensive care unit (ICU) nonseptic, and 14 ICU patients with sepsis were included in this prospective study. Plasma cholesterol, triglyceride, and vitamin E levels were determined by routine laboratory tests. Superoxide anion production was measured in the venous blood by chemiluminescence technique after phorbol myristate acetate stimulation. Effects of vitamin E and simvastatin on O2- degree production was investigated ex vivo. Luminescence was indexed to the leukocyte count. We also investigated the in vitro effect of simvastatin on translocation of NADPH oxidase p21 Rac2 subunit in THP-1 monocytic cell line. The ratio of vitamin E/cholesterol + triglycerides was significantly decreased in septic as compared with nonseptic patients and volunteers. The O2- degree production was significantly higher in the group of septic patients than in the others, regardless of the polymorphonuclear leukocyte count. Vitamin E and simvastatin induced ex vivo an inhibition of O2- degree production of 20% and 40% respectively. In vitro, simvastatin inhibited phorbol myristate acetate-induced- O2- degree production by monocytes through NADPH oxidase inactivation. We conclude that sepsis is associated with a significant decrease in vitamin E and an overproduction of O2- degree. Vitamin E and simvastatin lessen this phenomenon through NADPH oxidase inactivation.
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PMID:Superoxide anion overproduction in sepsis: effects of vitamin e and simvastatin. 1520 99

Staphylococcus epidermidis releases a group of peptides termed phenol-soluble modulin (PSM) that stimulate macrophages. The structure of 3 peptides (PSM alpha, PSM beta, and PSM gamma ) have been described. We report a fourth peptide (PSM delta ), which is a 23mer with the structure fMSIVSTIIEVVKTIVDIVKKFKK. The gene for each of the 4 peptides was introduced singly into Staphylococcus carnosus, and the PSM-like activity of culture medium and bacterial extract were significantly greater than those of the parent strain. PSM peptides from each of the S. carnosus-expressing strains were purified and analyzed by liquid chromatography-mass spectrometry. The products, which appeared to form aggregates, were active in the activation of human immunodeficiency virus type 1 long-terminal repeat and the production of tumor necrosis factor- alpha by the macrophage cell line THP-1. These findings suggest that PSM peptides are responsible, in part, for the modulin-like activity of staphylococci and may contribute to the development of severe staphylococcal sepsis.
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PMID:Activity of Staphylococcus epidermidis phenol-soluble modulin peptides expressed in Staphylococcus carnosus. 1527 3

Monocytes play a key role in mobilization of the immune response during sepsis. In response to LPS, monocytes produce both proinflammatory mediators and regulatory proteins that counteract the inflammation and oxidative stress. In murine macrophages, LPS stimulates expression of heme oxygenase 1 (HO-1), a cytoprotective enzyme that catalyzes the degradation of heme. The HO-1 5'-untranslated region, similarly to other cytoprotective genes, contains antioxidant-response elements (AREs) that can bind the transcription factor NF-E2-related factor 2 (Nrf2). At present, the role of Nrf2 in LPS-induced HO-1 expression in monocytic cells has not been investigated. In this study, LPS induced HO-1 mRNA and protein expression in human monocytes and THP-1 cells. Nrf2 translocated from the cytosol to the nucleus in response to LPS and bound to the ARE site in the human HO-1 promoter. In addition, a dominant negative Nrf2 mutant inhibited LPS-induced HO-1 mRNA expression but not TNF-alpha mRNA expression in THP-1 cells. Ro-31-8220, a pan-protein kinase C (PKC) inhibitor, and Go6976, a classical PKC inhibitor, blunted LPS-induced HO-1 mRNA expression in monocytes and THP-1 cells. Both PKC inhibitors also blocked LPS-induced Nrf2 binding to the ARE. These results indicate that LPS-induced HO-1 expression in human monocytic cells requires Nrf2 and PKC.
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PMID:Lipopolysaccharide-induced heme oxygenase-1 expression in human monocytic cells is mediated via Nrf2 and protein kinase C. 1617 82

Flagellin is the major protein component of the flagella from motile bacteria and was identified as the ligand for toll-like receptor (TLR)-5. Whereas its effects on epithelial cells have been studied in detail, activation of human peripheral blood mononuclear cells (PBMC) by flagellin is characterized only partially. By using the recombinant protein of Salmonella muenchen we confirm the proinflammatory nature of flagellin as detected by nuclear factor-kappaB activation and interleukin (IL)-8 production. Aim of the current study was to elucidate in PBMC effects of flagellin on IL-18 and Th1-like cytokine responses. We report that flagellin in pathophysiologically relevant concentrations augmented release of mature IL-18 by THP-1 monocytes, PBMC, and whole blood stimulated with nigericin or by ATP-mediated P2X7 purinergic receptor activation. Further key functions of the IL-18/IL-12/interferon-gamma (IFNgamma) pathway were upregulated by flagellin. Flagellin synergized with IL-12 for production of IFN-gamma and augmented secretion of interferon-inducible protein-10, a CXC-chemokine that is key to the generation of Th1-type responses. In contrast, neither IL-18-binding protein nor IL-4 was affected. Taken together, the present data demonstrate for the first time that flagellin at concentrations that are detectable in the blood compartment during sepsis efficiently enhances the IL-18/IL-12/IFNgamma pathway and thus Th1-like cytokine responses in PBMC.
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PMID:Interleukin-18 secretion and Th1-like cytokine responses in human peripheral blood mononuclear cells under the influence of the toll-like receptor-5 ligand flagellin. 1644 39

Human monocyte leukemia cell line THP-1 was stimulated with lipopolysaccharide (LPS) to simulate the sepsis model and the expression of human glucocorticoid receptor-alpha (GR-alpha) mRNA in montocytes with endotoxin tolerance was investigated. THP-1 cells were cultured in serum-free medium, randomly divided into groups A, B, C, D and E, and stimulated with 0, 10, 10, 100, 0 ng/mL LPS for 24 h followed with 100, 100, 10, 100, 0 ng/mL LPS for another 24 h respectively. The expression of GR-alpha mRNA was detected by semi-quantitative reverse transcriptional polymerase chain reaction. Tumor necrosis factor-alpha (TNF-alpha) was determined by enzyme linked immunosorbent assay (ELISA). The results showed that the A values of GR-alpha/beta-actin in groups A, B, C, D and E was 0.607 +/- 0.006, 0.368 +/- 0.005, 0.484 +/- 0.008, 0.509 +/- 0.004 and 0.564 +/- 0.014 respectively with the difference being significant among the groups (P < 0.05). The GR-alpha mRNA expression was negatively correlated with the TNF-alpha expression (P < 0.01). It was concluded that the down-regulation of the expression of GR-alpha mRNA in endotoxin tolerance THP-1 cells might play an important role in the development of endotoxin tolerance in THP-1 cells.
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PMID:Correlation between endotoxin tolerance in human monocyte leukemia cell line THP-1 with glucocorticoid receptor-alpha. 1671 Oct

Activated protein C is the first effective biological therapy for the treatment of severe sepsis. Although activated protein C is well established as a physiological anticoagulant, emerging data suggest that it also exerts anti-inflammatory and antiapoptotic effects. In this study, we investigated the ability of activated protein C to modulate monocyte apoptosis, inflammation, phagocytosis, and adhesion. Using the immortalized human monocytic cell line THP-1, we demonstrated that activated protein C inhibited camptothecin-induced apoptosis in a dose-dependent manner. The antiapoptotic effect of activated protein C requires its serine protease domain and is dependent on the endothelial cell protein C receptor and protease-activated receptor-1. In primary blood monocytes from healthy individuals, activated protein C inhibited spontaneous apoptosis. With respect to inflammation, activated protein C inhibited the production of TNF, IL-1beta, IL-6, and IL-8 by LPS-stimulated THP-1 cells. Activated protein C did not influence the phagocytic internalization of Gram-negative and Gram-positive bioparticles by THP-1 cells or by primary blood monocytes. Activated protein C also did not affect the expression of adhesion molecules by LPS-stimulated blood monocytes nor the ability of monocytes to adhere to LPS-stimulated endothelial cells. We hypothesize that the protective effect of activated protein C in sepsis reflects, in part, its ability to prolong monocyte survival in a manner that selectively inhibits inflammatory cytokine production while maintaining phagocytosis and adherence capabilities, thereby promoting antimicrobial properties while limiting tissue damage.
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PMID:Modulation of monocyte function by activated protein C, a natural anticoagulant. 1688 70

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