Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor (TNF) is considered to be a pivotal mediator of endotoxin-induced lethality. To assess the intermediate role of TNF in specific systemic inflammatory responses known to contribute to tissue injury in endotoxemia, eight healthy adult chimpanzees were intravenously injected with Escherichia coli endotoxin (4 ng/kg). In four of these animals the administration of endotoxin was followed immediately by a bolus intravenous injection of an anti-TNF monoclonal antibody (15 mg/kg). Treatment with anti-TNF completely prevented the endotoxin-induced increase in serum TNF activity, and profoundly reduced the appearance of interleukin-6 and -8 (both P < .05). Neutrophilia and lymphopenia were not affected by anti-TNF, whereas neutrophil degranulation, as measured by the plasma concentrations of elastase-alpha 1-antitrypsin complexes, was only slightly reduced (peak levels after endotoxin alone 31.0 +/- 3.4 ng/mL, versus 25.5 +/- 3.4 ng/mL after endotoxin with anti-TNF; P < .05). Anti-TNF did not influence endotoxin-induced activation of the coagulation system, as reflected by unchanged increases in the plasma concentrations of the prothrombin fragment F1 + 2 and thrombin-antithrombin III complexes. In contrast, anti-TNF strongly attenuated the activation of the fibrinolytic system, ie, peak plasma levels of plasmin-alpha 2-antiplasmin were 33.8 +/- 11.1 nmol/L after endotoxin alone and 17.0 +/- 2.9 nmol/L after endotoxin with anti-TNF (P < .05). These results suggest that TNF is not the common mediator of systemic inflammatory changes in low-grade endotoxemia. Moreover, the finding that in this mild model anti-TNF specifically inhibited fibrinolysis suggests that treatment with anti-TNF potentially may enhance the tendency towards microvascular thrombosis in sepsis.
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PMID:Differential effects of anti-tumor necrosis factor monoclonal antibodies on systemic inflammatory responses in experimental endotoxemia in chimpanzees. 828 42

The vascular endothelium plays a central role in the regulation of extrinsic fibrinolysis and thus maintains vascular patency through clot dissolution. Plasminogen activation provides an important source of localized proteolytic activity not only during fibrinolysis but also during a variety of other physiological and pathological processes. Numerous studies have indicated that human endothelial cells can directly synthesize and secrete plasminogen activators (PA) and inhibitors of these activators. PAs specifically hydrolyse a single arginine-valine bond in plasminogen, an abundant and widely distributed plasma zymogen, to form the broad spectrum serine protease, plasmin. Tissue type-PA (t-PA) and urokinase type PA (u-PA) forms of PA have been described in endothelial cells, although t-PA production and secretion is elevated most frequently. The tPA form of PA functions predominantly in endothelial cell mediated fibrinolysis, while uPA is involved in tissue remodeling. During inflammatory reactions activated mononuclear phagocytes produce a variety of cytokines which may influence the phenotype of the endothelium through a process termed "endothelial cell activation". Tumor necrosis factor alpha (TNF alpha), a mononuclear cytokine, is a distinct polypeptide of Mr 17,000 and has been implicated as a mediator of gram negative induced sepsis as well as angiogenesis. TNF alpha is known to interact with specific endothelial cell receptors and to alter endothelial coagulant and anticoagulant properties implying that cytokines may be potent modulators of hemostasis. Recent observations have indicated that TNF alpha and lymphotoxin (TNF beta) can promote the expression, synthesis and secretion of urokinase plasminogen activator (uPA) in human endothelial cells. The upregulation of uPA results in an alteration in the fibrinolytic capacity of endothelial cells and allows cells the selective ability to degrade and invade underlying subendothelial extracellular matrix (ECM). Endothelial cells treated with TNF alpha also display, in an in vitro angiogenic assay, the ability to invade Matrigel and reorganize into tube-like structures, unlike control cultures. The effects of TNF alpha on the PA proteolytic system of endothelial cells, the biological significance of this event and potential in vivo consequences will be discussed. In addition, the influence of cytokine regulatory control systems will be described, since it is becoming increasingly clear that cytokines do not act in isolation. The vascular endothelium serves as a widely distributed anatomical interface between the blood and tissue with diverse capabilities, performing distinctive biologic functions at different sites and within specific organs.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cytokine regulation of endothelial cell extracellular proteolysis. 835 23

A brief explanation of the molecular markers of coagulation, fibrinolysis and endothelial cell activation was done. The clinical significance of markers, such as, soluble fibrin monomer complex, FDP D-dimer, prothrombin fragment 1 + 2, thrombin-antithrombin III complex, plasmin-alpha 2 plasmin inhibitor complex and plasma thrombomodulin in our patients with disseminated intravascular coagulation (DIC) due to abdominal sepsis and malignancy is discussed. The coagulopathy in the DIC patients due to abdominal sepsis had a different aspect from that in the DIC patients due to malignancy. Activation of the coagulation and fibrinolytic systems in sepsis was milder than that in malignancy, despite the decrease of antithrombin III activity in the patients with sepsis. In the patients with sepsis, granulocyte elastase was increased. It was proposed that the coagulopathy was caused not only thrombin formation but also by granulocyte proteinase. It could be expected that the pathophysiology of disseminated intravascular coagulation should be clarified, because of the high sensitivity.
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PMID:[Advancement in the diagnosis of disseminated intravascular coagulation for the surgeon]. 838 85

Plasmin-alpha2-antiplasmin complexes (PAP) are considered good markers of fibrinolytic activation in vivo. The presence of neoantigens in these complexes offers the possibility to develop specific immunoassays to determine PAP levels. We have developed a sensitive PAP purification method in vitro by adding urokinase to fresh plasma followed by affinity chromatography to lysine-sepharose and elution with epsilon-aminocaproic acid. This material, characterized by SDS-PAGE and Western blotting, was used to raise monoclonal antibodies (MoAbs). We describe a new enzyme linked immunosorbent assay (ELISA) to quantify PAP complexes in plasma. The assay follows the sandwich principle and is based on two MoAbs, CPL12 and CPL15, that bind to the modified alpha2-antiplasmin moiety and the plasmin moiety of the complex respectively. The calibration curve was constructed with definite concentrations of purified PAP. The lower limit of the assay is 75 ng/ml and the variation coefficients are 3.5% (intra-assay) and 10-6% (interassay). A mean value of 573.5+/-131.4 ng/ml was obtained from PAP concentration in a healthy population (n = 30). Significantly higher PAP levels were observed under diverse clinical conditions in which fibrinolysis is activated: clinical sepsis, acute myocardial infarction (AMI), malignancy, diabetes, pregnancy, elderly people and thrombolytic therapy. From our results we conclude that this ELISA is suitable to measure in vivo plasma PAP levels.
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PMID:Development and clinical application of a new ELISA assay to determine plasmin-alpha2-antiplasmin complexes in plasma. 861 97

In previous studies, we have shown that administration of monoclonal antibody (MoAb) C6B7 against human factor XII to baboons challenged with a lethal dose of Escherichia coli abrogates activation of the contact system and modulates secondary hypotension. To evaluate the contribution of activated contact proteases to the appearance of other inflammatory mediators in this experimental model of sepsis, we studied the effect of administration of MoAb C6B7 on activation of complement and fibrinolytic cascades, stimulation of neutrophil degranulation, and release of the proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Activation of the complement system, as reflected by circulating C3b/c and C4b/c levels, was significantly reduced in five animals that had received MoAb C6B7 before a lethal dose of E coli as compared with five control animals that had been given a lethal challenge only. Inhibition of contact activation also modulated the fibrinolytic response, since the release of tissue-type plasminogen activator (t-PA) and the appearance of plasmin-alpha2-antiplasmin (PAP) complexes into the circulation was significantly attenuated upon pretreatment with anti-factor XII MoAb. In contrast, plasma levels of plasminogen activator inhibitor (PAI) were modestly enhanced in the treatment group. Degranulation of neutrophils, as assessed by circulating elastase-alpha1-protease inhibitor complexes, and release of IL-6 but not of TNF-alpha was decreased in anti-factor XII-treated animals. Observed differences in the inflammatory response between treatment and control groups were not likely due to different challenges, since the number of E coli that had been infused, as well as circulating levels of endotoxin after the challenge, were similar for both groups. These data suggest that activation of the contact system modulates directly or indirectly various mediator systems involved in the inflammatory response during severe sepsis in nonhuman primates.
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PMID:Inhibition of factor XII in septic baboons attenuates the activation of complement and fibrinolytic systems and reduces the release of interleukin-6 and neutrophil elastase. 863 Mar 96

The plasmin/plasminogen system of enzymes may be involved in leukocyte migration through the endothelial cell layer of the vascular wall during inflammatory processes associated with vascular injury, atherosclerosis, and sepsis. Synthesis of plasminogen activator inhibitor type 1 (PAI-1) by the endothelium may protect these cells and the subendothelial cell matrix from excessive degradation and retard leukocyte migration. We report in this work for the first time the down-regulation of both basal and thrombin- or endotoxin-induced PAI-1 in cultured human endothelial cells by the activated T cell product, IFN-gamma. Down-regulation of basal and thrombin- or endotoxin-induced endothelial PAI-1 protein by IFN-gamma was found to be both time and dose dependent. Decreases of up to 71% relative to thrombin- or endotoxin-treated controls, using an optimal IFN-gamma concentration of between 20 and 200 U/ml, were found for human macrovascular and microvascular endothelial cells. However, IFN-gamma did not appear to affect IL-1 alpha- and TNF-alpha-induced levels of PAI-1 protein or mRNA in these cells. Northern blot analysis paralleled protein results, showing decreases in specific endothelial cell thrombin- or LPS-induced PAI-1 mRNA expression, respectively, after incubation with IFN-gamma for 24 h. These results suggest a means by which the migration of circulating leukocytes through endothelial cell layers during inflammation may be facilitated.
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PMID:IFN-gamma inhibits thrombin- and endotoxin-induced plasminogen activator inhibitor type 1 in human endothelial cells. 880 64

Vascular pathophysiology at the sites of bacterial infection and cancerous tissues share numerous common events similar to inflammatory tissue. Among them enhanced vascular permeability is the universal and hallmark event mediated by bradykinin. All 16 or more bacterial or fungal proteases we have examined activated one or more steps of the kinin generating Hageman-factor-kallikrein cascade. In the meantime, most of the microbial proteases rapidly inactivated various plasma inhibitors such as alpha 1-protease inhibitor and alpha 2-macroglobulin. In addition to the extracellular proteases, bacterial cell wall components (negatively charged LPS) of gram-negative bacteria and teichoic acid moieties of gram-positive bacteria activate the Hageman-factor-kallikrein system and exert hypotensive effects via kinin generation. Endotoxin (LPS) also induces nitric oxide synthase (NOS) which appears to exhibit a rather slow, but significant, effect in relaxing the vascular tone of the infected animal (thus hypotension). Furthermore, bacterial proteases can activate the matrix metalloproteinase (collagenase) resulting in exacerbation of tissue injury in the diseased animal. Many tumor cells or tissues excrete plasminogen activator, and hence activate plasminogen. The plasmin thus generated activates procollagenases, as well as the Hageman-factor-kallikrein system, resulting in pronounced extravasation. Fluid accumulation in pleural and ascitic carcinomatoses is largely due to the activated bradykinin-generating system. We can also demonstrate and control enhanced vascular permeability using kallikrein inhibitors, especially the polymer-conjugated soybean trypsin inhibitor which exhibits a prolonged plasma t1/2, kinin antagonists, NOS inhibitors, NO scavengers, inhibitors of prostaglandins and others. Bacterial proteases induce shock in mice which can be prevented by the soybean trypsin inhibitor by blocking the kallikrein-kinin cascade. Therapeutic use of kinin antagonists and a kallikrein inhibitor has been made for infectious diseases such as septicemia and in tumor pathology.
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PMID:Bradykinin and nitric oxide in infectious disease and cancer. 885 54

alpha2-HS glycoprotein is a major protein of human plasma whose function is still obscure. A proteolytically processed form of alpha2-HS glycoprotein lacking a segment of 40 amino acid residues bridging its heavy and light chain portions ("connecting peptide") has been described suggesting that this peptide is released by post-translational processing to fulfill biological role(s) of alpha2-HS glycoprotein. To test this hypothesis we investigated how the connecting peptide is released from the parental molecule by limited proteolysis. We developed monoclonal antibodies to various portions of the connecting peptide and its NH2-terminal flanking region which cross-react with the native alpha2-HS glycoprotein. Purified alpha2-HS glycoprotein from human plasma was subjected to limited proteolysis by proteinases including trypsin, chymotrypsin, elastase plasmin, kallikrein, thrombin, and renin. Immunoprint analysis of the proteolytic digests indicated that alpha2-HS glycoprotein is readily cleaved in its connecting peptide region. NH2-terminal amino sequence analysis of the generated fragments demonstrated that a single proteinase, chymotrypsin, cleaves the critical Leu-Leu bond flanking the NH2-terminal portion of the connecting peptide region. Most but not all of the other proteinase cleavage sites map to a short stretch of 9 residues located in the center portion of the connecting peptide region. Immunoprint analysis of plasma samples from patients with sepsis demonstrate that the connecting peptide region is cleaved under pathological conditions. Our results indicate that the connecting peptide and/or fragments thereof are readily releasable from alpha2-HS glycoprotein in vitro and in vivo.
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PMID:Limited proteolysis of human alpha2-HS glycoprotein/fetuin. Evidence that a chymotryptic activity can release the connecting peptide. 894 Jan 98

Upon stimulation, polymorphonuclear leucocytes (PMNs) release potent serine proteases, i.e. elastase, cathepsin G and proteinase 3, which contribute to the degradation of tissue and plasma components. Here, we describe the development of a plasma test to assess PMN-mediated fibrinogenolysis as a biochemical marker for actual PMN-derived proteolysis in vivo, useful for monitoring therapeutic efficacy, i.e. of elastase inhibitors. We generated a monoclonal antibody (MAb), designated 1-1/B3, with a high affinity for elastase-degraded fibrinogen (EDF). The epitope for 1-1/B3 becomes exposed in a time-dependent manner during digestion of fibrinogen with purified PMN-derived serine proteases and with isolated PMNs in vitro. However, 1-1/B3 does not react with plasma fibrinogen or with fibrin(ogen) degradation products generated by plasmin or by other active proteases that may occur locally, i.e. metalloproteases and lysosomal cathepsins. On the basis of MAb 1-1/B3, we developed a plasma test for the assessment of PMN-mediated fibrin(ogen) degradation products (PMN-FDP). In a panel of control plasmas, we observed concentrations of PMN-FDP of 8.2 +/- 0.9 ng mL-1 (n = 18). These values were increased twofold in patients with alpha 1-proteinase inhibitor deficiency (18.6 +/- 3.3 ng mL-1; n = 12; P < 0.0001) and even more in patients with sepsis (365.7 +/- 97.7 ng mL-1; n = 16; P < 0.0001). Furthermore, synovial tissue extracts from patients with rheumatoid arthritis contained increased levels of PMN-FDP, compared with synovial tissue extracts (P < 0.005) from patients with osteoarthritis.
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PMID:An enzyme immunoassay for polymorphonuclear leucocyte-mediated fibrinogenolysis. 906 9

Extravascular fibrin formation and dissolution is a pivotal event in numerous inflammatory and malignant diseases. In inflammatory cells such as monocytes/macrophages, neutrophil granulocytes appear to interact intimately with hemostasis and regulate the activity of the cascade systems of coagulation and fibrinolysis. Proteases such as neutrophil elastase are thought to influence components of hemostasis, and furthermore provide an alternative pathway of fibrinolysis. Histological, experimental, and clinical data suggest that extravascular fibrinolysis, mediated both by the plasmin system and by proteases like neutrophil elastase, is a prominent finding in various diseases such as lung cancer, chronic inflammatory bowel disease, vasculitis and connective tissue disease, bacterial sepsis, and septic shock.
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PMID:The role of inflammatory cells and their proteases in extravascular fibrinolysis. 912 14


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