Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Elevated levels of soluble fibrin in plasma indicate that thrombin converts fibrinogen to fibrin without sufficient inhibitory control. Therefore, measurement of soluble fibrin (SF) in plasma may be considered as a laboratory test for intravascular coagulation. We have demonstrated that a new immunoassay for detection of SF in human plasma (Lill et al., Blood Coag Fibrinol 1993; 4: 97-102), based on a fibrin specific monoclonal antibody, also detects porcine SF with high sensitivity. Thrombin-dependent generation of SF in porcine plasma in vitro resulted in increased reactivity of the assay system, which was time and dose dependent. Dextran sulphate (DXS) and bacterial lipopolysaccharide (LPS) were used as stimuli in in vivo experiments in pigs. Plasma levels of SF increased steadily after intravenous administration of DXS (5 mg/kg for 1 h) to 38 +/- 7.8 micrograms/ml (mean +/- SEM) at 2 h, whereas LPS (2 micrograms/kg/h for 6 h) markedly increased plasma SF levels to over 120 micrograms/ml (at 6 h) after a lag phase of 2 h. In conclusion, this new immunoassay for human fibrin allows specific and sensitive detection of soluble fibrin in porcine plasma.
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PMID:Sensitive detection of the activation state of blood coagulation in porcine DIC models by a new fibrin immunoassay. 845 35

We investigated the effect of activated protein C (APC) on lipopolysaccharide (LPS)-induced pulmonary vascular injury in rats to investigate the possible usefulness of APC as a treatment for adult respiratory distress syndrome. Intravenously administered LPS (5 mg/kg) significantly increased pulmonary vascular permeability. APC prevented the LPS-induced increase in pulmonary vascular permeability observed at 6 hours. Heparin plus antithrombin III (ATIII) and active site-blocked factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, inhibited LPS-induced coagulopathy but did not prevent LPS-induced pulmonary vascular injury. LPS-induced pulmonary vascular injury was significantly attenuated in rats with nitrogen mustard-induced leukocytopenia and in rats treated with ONO-5046, a potent granulocyte elastase inhibitor. Administration of LPS also increased pulmonary accumulation of leukocytes, as evaluated by measurement of myeloperoxidase activity in the lungs. APC significantly reduced LPS-induced increases in pulmonary accumulation of leukocytes at 1 hour. Neither ATIII plus heparin nor DEGR-Xa inhibited leukocyte accumulation. Active site-blocked APC (DIP-APC) prevented neither the LPS-induced pulmonary accumulation of leukocytes nor the LPS-induced increase in pulmonary vascular permeability. These results suggest that the mechanism of APC inhibition of LPS-induced pulmonary vascular injury was independent of its anticoagulant activity and was related to its ability to inhibit accumulation of leukocytes. In addition, these findings suggest that the serine protease activity of APC may be essential to its inhibitory effect on LPS-induced pulmonary accumulation of leukocytes and subsequent pulmonary vascular injury.
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PMID:Activated protein C attenuates endotoxin-induced pulmonary vascular injury by inhibiting activated leukocytes in rats. 855 86

The nitric oxide (NO) production by porcine aortic valve endothelial cells was estimated in cusps incubated at 37 degrees C by measuring their cyclic GMP content and the nitrite levels of the incubation medium. After a stabilization period, incubation for 5 min with acetylcholine, bradykinin, ADP and bovine thrombin resulted in a receptor-mediated increase in cyclic GMP which could be blocked by EGTA, N-omega-nitro-L-arginine methyl ester (L-NAME) and NG-monomethyl-L-arginine (L-NMMA). Incubation with lipopolysaccharide (endotoxin) from E. coli O111:B4 or bovine for 5 h, dose-dependently increased nitrite production as well as cyclic GMP content. The elevated nitrite production was completely abolished in the presence of the protein synthesis inhibitor cycloheximide, was reduced by more than 50% by dexamethasone but was not affected by EGTA. L-NMMA dose-dependently reduced the increased nitrite production and cyclic GMP content. These results suggest that besides the presence of a constitutive NO synthase in porcine aortic valve endothelial cells thrombin, like lipopolysaccharide, triggers the de novo expression of an inducible Ca(2+)-independent NO synthase.
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PMID:Thrombin triggers the de novo expression of an inducible NO synthase in porcine aortic valve endothelial cells. 856 77

Adult respiratory distress syndrome (ARDS) is a serious complication of disseminated intravascular coagulation (DIC) or multiple organ failure. To determine whether recombinant soluble human thrombomodulin (rsTM) may be useful in treating ARDS due to sepsis, we investigated the effect of rsTM on lipopolysaccharide (LPS)-induced pulmonary vascular injury in rats. The intravenous administration of rsTM prevented the increase in pulmonary vascular permeability induced by LPS. Neither heparin plus antithrombin III (AT III) nor dansyl Glu Gly Arg chloromethyl ketone-treated factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, prevented LPS-induced vascular injury. The agents rsTM, heparin plus AT III, and DEGR-Xa all significantly inhibited the LPS-induced intravascular coagulation. Recombinant soluble TM pretreated with a monoclonal antibody (moAb) that inhibits protein C activation by rsTM did not prevent the LPS-induced vascular injury; in contrast, rsTM pretreated with a moAb that does not affect thrombin binding or protein C activation by rsTM prevented vascular injury. Administration of activated protein C (APC) also prevented vascular injury. LPS-induced pulmonary vascular injury was significantly reduced in rats with leukopenia induced by nitrogen mustard and by ONO-5046, a potent inhibitor of granulocyte elastase. Results suggest that rsTM prevents LPS-induced pulmonary vascular injury via protein C activation and that the APC-induced prevention of vascular injury is independent of its anticoagulant activity, but dependent on its ability to inhibit leukocyte activation.
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PMID:Recombinant human soluble thrombomodulin reduces endotoxin-induced pulmonary vascular injury via protein C activation in rats. 860 7

We developed a sensitive tissue factor (TF) chromogenic assay on a limited number of endothelial cells (EC), performed in microtiter plates, and which uses a normal pooled human plasma instead of purified concentrates as a source of coagulation factors. Primary cultures of human umbilical vein EC (HUVEC), both unstimulated and stimulated by lipopolysaccharide (LPS) were incubated with 50 microliters of of diluted normal human plasma (NHP) and 50 microliters of Factor Xa-specific chromogenic substrate (CBS 31-39, Stago, France). Hirudin was added at 4 U/ml to the plasma/CBS 31-39 mixture to inhibit thrombin generation. Optical densities were read at 405 nm and corresponding amounts of generated factor Xa were expressed in mU Xa/well using a standard curve established with purified human Factor Xa. The following parameters were then defined: the number of EC to plate (10(4) EC/well of a 96-well plate), the plasma-test dilution (1:20), the concentration of CBS 31-39 (0.50 mM) and the incubation time of reagents with EC (2 hours). The procoagulant activity (PCA) measured was only dependent on TF since it was no longer detectable either when FVII-deficient plasma was tested instead of normal human plasma or when PCA assays were performed in the presence of a blocking anti-human TF monoclonal antibody. This method allowed detection of a TF-dependent PCA on as few as 1000 EC per well. In addition, TF expression equal to 50% of maximal values was measured with LPS concentrations as low as 1 ng/ml, supporting the high sensitivity of the assay.
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PMID:A simplified and low-cost one-stage chromogenic assay for tissue factor dependent procoagulant activity of endothelial cells. 861 Feb 81

Acute inflammatory illnesses, including the sepsis syndrome, often include a component of coagulation. A human whole blood culture system was developed so that the relationship between coagulation activation and cytokine responses in the presence or absence of lipopolysaccharide (LPS) could be evaluated. In the absence of LPS stimulation, coagulation activation resulted in a novel pattern of cytokine production. During a 4-hour culture of coagulating blood, significant production of interleukin-8 (IL-8; >2,000 pg/mL) was observed, whereas other proinflammatory cytokines including IL-1 beta, IL-6, or tumor necrosis factor a were undetectable or less than 35 pg/mL. The cytokine profile was distinct from that of fully anticoagulated, LPS-stimulated blood, which showed levels of all the indicated proinflammatory cytokines > or = 2,000 pg/mL over the same time period. Over 24 to 48 hours, the coagulation-induced cytokine response was characterized by marked and sustained IL-8 production, limited IL-6 generation (with kinetics delayed relative to IL-8), and minimal or undetectable tumor necrosis factor alpha levels. The magnitude of the whole blood IL-8 response correlated with the level of coagulation activation as determined by measurement of thrombin-antithrombin III complex formation. The combined stimuli of coagulation activation and LPS challenge induced a synergistic enhancement of IL-8 production but not of IL-6. Coagulation-induced cytokine production and the synergistic production of IL-8 by coagulation and LPS could be attenuated by hirudin or tissue factor pathway inhibitor (TFPI). Studies to elucidate mechanisms implicated (1) the TFPI third Kunitz and carboxy-terminus as important structural components for TFPI regulation of coagulation activation and (2) thrombin as a candidate mediator of the mononuclear cell cytokine response to coagulation activation. In summary, a unique aspect of the crosstalk between the coagulation and cytokine cascades in whole blood is shown with the identification of IL-8 as a key proinflammatory participant.
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PMID:The proinflammatory cytokine response to coagulation and endotoxin in whole blood. 865 18

The administration of gram-negative bacterial lipopolysaccharide (LPS) to rats results in hepatic parenchymal cell injury within 6 hr. The coagulation system is critical to the pathogenesis, but previously reported results suggested that its critical role is independent of insoluble clot formation and that thrombin may be a key mediator of liver injury. To test the hypothesis that thrombin is involved in LPS-induced liver injury, animals were treated with the selective thrombin inhibitor, hirudin. The hirudin treatment regimen effectively inhibited thrombin, as evidenced by prolonged activated partial thromboplastin time and by maintenance of plasma fibrinogen concentrations in LPS-treated rats. Treatment with hirudin prevented LPS-induced liver injury, assessed by plasma alanine aminotransferase activity and histological evidence of hepatocellular necrosis. Previous studies have shown that LPS exposure results in the accumulation of neutrophils and platelets within the liver and that both of these cell types are critical for the development of LPS-induced liver injury. Hirudin attenuated in part the decrease in blood platelet concentration that accompanied LPS administration, but did not alter hepatic platelet or neutrophil accumulation. These results support the hypothesis that thrombin is required for hepatic injury from LPS exposure, but that it does not act by promoting the accumulation of platelets or neutrophils within the liver.
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PMID:The thrombin inhibitor, hirudin, attenuates lipopolysaccharide-induced liver injury in the rat. 876 73

The direct effects of recombinant human erythropoietin(rHuEPO) on coagulation and fibrinolysis factors were evaluated in a cultured endothelial cell (EC) system. Confluent quiescent ECs were incubated with or without 5.0 U/ml rHuEPO for 1, 6, and 18 hours, and supernatant concentrations of plasminogen activator inhibitor-1 (PAI-1): antigen (Ag), tissue plasminogen activator and thrombomodulin, and supernatant activities of tissue factor pathway inhibitor and von Willebrand factor were measured. The results showed that only PAI-1 levels were increased by the presence of rHuEPO. In order to assess the effect of rHuEPO on PAI-1 production by EC more precisely, confluent ECs were incubated with various doses of rHuEPO (0, 1.0, 2.5, 5.0, 10.0 U/ml) for 1, 6, 12, and 18 hours, and PAI-1:Ag concentrations in the supernatants of media were measured. PAI-1:Ag in the supernatants were increased by the presence of rHuEPO at all incubation times (P < 0.01) and the increase in PAI-1:Ag was dependent on rHuEPO concentration. The increases in PAI-1:Ag by 5.0 U/ml rHuEPO were comparable to those by 0.1 U/ml tumor necrosis factor-alpha, 1.0 microgram/ml lipopolysaccharide, and 0.5 U/ml thrombin. The increase in PAI-1:Ag by rHuEPO was suppressed by pre-incubation with 10 micrograms/ml cycloheximide (P < 0.01) or 0.2 microgram/ml actinomycin D (P < 0.01). These results indicate that rHuEPO directly stimulates PAI-1 production in cultured EC via de novo protein and RNA syntheses.
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PMID:rHuEPO enhances the production of plasminogen activator inhibitor-1 in cultured endothelial cells. 880 78

Thrombosis and disseminated intravascular coagulation (DIC) are common complications of infections. Abnormal activation of coagulation is due in part of expression of tissue factor on intravascular cells in response to cytokines, including interleukin-1 beta (IL1 beta ) and tumor necrosis factor (TNF). Both TNF and IL1 beta are thought to play significant roles in producing the pathologic manifestations of sepsis. Therefore, we examined the effects of thrombin on TNF and IL1 beta secretion of monocytes, and the ability of monocyte products to promote tissue factor expression by endothelial cells. Human monocytes were treated with thrombin or a thrombin receptor agonist peptide (SFLLRN), and/or bacterial lipopolysaccharide (LPS). The agonists were removed, and monocytes cultured 18 hours. The monocyte-conditioned supernatants were assayed for TNF and IL1 beta antigen, and for their ability to induce tissue factor expression on human umbilical vein endothelial cells and the Ea.hy endothelial cell line. Thrombin alone did not promote monocyte TNF or IL-1 beta secretion. However, thrombin enhanced LPS-induced TNF and IL1 secretion. Supernatants from monocytes exposed to LPS plus thrombin promoted greater tissue factor expression on endothelial cells than supernatants from those treated with LPS only. SFLLRN did not increase TNF secretion in response to LPS, but did enhance LPS-induced IL1 beta secretion and tissue factor-inducing activity. Neither SFLLRN nor active thrombin augmented the level of mRNA for TNF above that induced by LPS alone. However, both increased the LPS-induced level of IL1 beta message. Thus, thrombin enhanced LPS-induced TNF and IL1 beta secretion by monocytes. Unexpectedly, the effects on these two cytokines were mediated by different mechanisms. Enhancement of LPS-induced IL1 beta secretion was largely mediated via the tethered ligand type thrombin receptor and correlated with an increase in the steady state level of mRNA. By contrast, enhanced TNF required proteolytically active thrombin, but was not mediated by the tethered ligand receptor. These data demonstrate that physiologically relevant amounts of thrombin can synergize with endotoxin to stimulate monokine release. Thrombin could thereby play a role in the complex network of mediators involved in the pathophysiology of sepsis. We speculate that limiting thrombin activity during DIC could be a beneficial adjunct in the management of sepsis.
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PMID:Thrombin enhances monocyte secretion of tumor necrosis factor and interleukin-1 beta by two distinct mechanisms. 884 45

Fibrin formation within the glomeruli has been observed in various forms of human and experimental glomerulonephritis and it may play an important role in progressive glomerular injury. Furthermore it has been hypothesized that glomerular fibrin deposition may occur through activation of either the intrinsic or extrinsic coagulation pathway. It has been demonstrated that a procoagulant activity (PCA) which is compatible with tissue factor is present in the glomeruli and becomes increased in human proliferative glomerulonephritis and in animal models of nephritis. Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation through its ability to inhibit tissue factor activity. TFPI is present in plasma and in platelets, and it is now thought to be produced mainly by endothelial cells. We examined whether human mesangial cells (HMC) could produce TFPI and attempted to clarify regulatory factors which affect TFPI production. Cultured HMC were used and TFPI in the cell supernatants was measured by ELISA using a specific antibody. Cultured HMC showed the production of TFPI. Immunoblot analysis revealed 40 kD protein of TFPI. The concentration of TFPI was significantly increased following the incubation with thrombin and heparin, including low molecular weight heparin, in a dose- and time-dependent manner. However, fetal calf serum, phorbol myristate acetate, lipopolysaccharide, IL-1 beta and tissue factor did not stimulate TFPI synthesis. Our data show that cultured HMC have the ability to produce TFPI which inhibits fibrin formation. It is possible that thrombin-induced enhancement of TFPI synthesis may be caused by the autoregulatory system of blood coagulation and that with heparin it may represent another anticoagulatory effect of heparin.
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PMID:Tissue factor pathway inhibitor production by human mesangial cells in culture. 886 34


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