Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor-alpha (TNF alpha) has been proposed as a mediator of endotoxin-induced lung injury. When given to sheep, TNF alpha mimics endotoxin (LPS) causing hypoxemia, pulmonary hypertension, leukopenia, reduced dynamic compliance (Cdyn), increased resistance to airflow (RL), exudation of lung lymph, and enhanced airway reactivity. TNF alpha also induces rapid release of thromboxane A2 (TxA2), prostaglandin E2 (PGE2), and prostacyclin (PGI2). We hypothesized that the inflammatory effects of TNF alpha are due at least in part to cyclooxygenase products, and therefore cyclooxygenase inhibition would have similar effects on TNF alpha-induced lung injury as has previously been demonstrated for LPS-induced lung damage. Using awake sheep with chronic lung lymph fistulas, we measured Cdyn, RL, and FRC using a whole-body plethysmograph. Pulmonary artery (Ppa), left atrial (PLA), and systemic arterial (Psa) pressures were recorded continuously. Arterial blood gases (for calculating AaPO2), leukocyte counts, and lymph samples (for prostanoid levels) were collected every 30 min. Eleven animals underwent paired random-order experiments receiving ibuprofen (14 mg/kg) 1 h before human recombinant TNF alpha (10 micrograms/kg), or an identical dose of TNF alpha alone. Within 15 min of initiating TNF alpha, Ppa doubled and remained elevated for 4 h. Ibuprofen prevented the early rise in Ppa after TNF alpha. In the group receiving TNF alpha alone, increases in Ppa were accompanied by a 60% decline in leukocyte count and a 50% increase in AaPo2 within 30 min. Ibuprofen prevented increases in AaPo2, but it had no effect on leukopenia or late increases in lymph flow.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The role of cyclooxygenase products in lung injury induced by tumor necrosis factor in sheep. 154 45

Tumor necrosis factor (TNF) may be involved in the disturbance of the procoagulant-fibrinolytic balance in septicemia, leading to microvascular thrombosis. To assess the dynamics of the fibrinolytic response to TNF in humans, we performed a crossover saline-controlled study in six healthy men, investigating the effects of a bolus intravenous injection of recombinant human TNF (50 micrograms/m2) on the stimulation and inhibition of plasminogen activation as well as on plasmin activity and inhibition. TNF induced a brief fourfold increase in the overall plasma plasminogen activator (PA) activity peaking after 1 h (p less than 0.0001), which was associated with rises in the antigenic levels of urokinase-type plasminogen activator (p less than 0.0001) and tissue-type plasminogen activator (p less than 0.0001). Plasminogen activator inhibitor type I antigen remained unchanged in the first hour, but showed a rapid eightfold increase thereafter (p less than 0.0001), which coincided with the decrease in PA activity. Generation of plasmin activity in the first hour was signified by an 11-fold rise in D-dimer levels (p less than 0.0001); inhibition of plasmin was reflected by a 36-fold rise in plasmin-alpha 2 antiplasmin complexes (p less than 0.0001), as well as by a transient 16% decrease in alpha 2-antiplasmin activity (p less than 0.01). In conclusion, TNF induced an early activation of the fibrinolytic system becoming maximal in 1 h, with a rapid inhibition thereafter. Earlier observations in the same subjects showed sustained coagulation activation for 6-12 h. The observed disbalance between the procoagulant and fibrinolytic mechanisms after TNF injection confirms the in vivo relevance of the effects of TNF on vascular endothelium in vitro and may explain the tendency towards microvascular thrombosis in septicemia.
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PMID:Fibrinolytic response to tumor necrosis factor in healthy subjects. 171 36

Tumor necrosis factor (TNF) induced by bacterial lipopolysaccharide (LPS) was shown to have an important role in precipitation of septic shock and disseminated intravascular clotting (DIC). At the endothelial level TNF down-regulates thrombomodulin (thus preventing protein C formation) and inhibits the production of tissue plasminogen activator (t-PA), thus impairing anticoagulant mechanisms. On the other hand, TNF up-regulates the production of procoagulant factors such as t-PA inhibitor (PAI), tissue factor and platelet activating factor (PAF). These effects create an imbalance between procoagulant and anticoagulant mechanisms, in favor of the former. TNF also activates polymorphonuclears (PMNs), and increases their chemotaxis and adherence to endothelial surfaces by up-regulation of specific endothelial (ELAM-1) and PMN (CDw18) adherence proteins. The damage inflicted by activated PMN to the endothelial cell promotes tissue factor exposure and PAI release, with initiation of the characteristic explosive coagulation process of DIC, facilitated by the dissociation between pro- and anticoagulant mechanisms induced by TNF. These newly discovered mechanisms precipitating septic shock and DIC enable consideration of new treatments for this condition as anti-TNF antibodies or TNF inhibitors, anti-ELAM-1 antibodies anti-tissue factor antibodies, administration of activated factor C, etc. These therapeutic approaches may revolutionize the treatment of septic shock and DIC in the next decade.
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PMID:Role of tumor necrosis factor in the pathogenesis of intravascular coagulopathy of sepsis: potential new therapeutic implications. 199 4

Tumor necrosis factor-alpha (TNF-alpha) was found to induce type-1 plasminogen activator inhibitor (PAI-1) antigen in the human fibrosarcoma cell line HT-1080, and PAI-1 and urokinase-type plasminogen activator (u-PA) antigens in the human carcinoma cell line T-CAR1; tissue-type plasminogen activator (t-PA) antigen was not affected or slightly decreased. The effects in HT-1080 and T-CAR1 cells were preceded by increases in the cellular levels of the corresponding mRNAs. Cycloheximide caused an increase of PAI-1 mRNA in T-CAR1 cells, but not in HT-1080 cells; during this increase the relative abundance of the two PAI-1 mRNA species, of 2.3 kb and 3.4 kb, respectively, changed strongly in favor of the longer transcript. We conclude that TNF-alpha may affect proteolytic activity in the microenvironment of cells in malignant tumors by affecting gene expression of u-PA and PAI-1.
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PMID:Tumor necrosis factor-alpha regulates mRNA for urokinase-type plasminogen activator and type-1 plasminogen activator inhibitor in human neoplastic cell lines. 250 Nov 20

Tumor necrosis factor-alpha (TNF-alpha) can bind to two distinct transmembrane receptors, the p55 and p75 TNF receptors. We compared the capability of two mutant TNF proteins with exclusive affinity for the p55 or p75 TNF receptor with that of wild type TNF, to activate the hemostatic mechanism in baboons. Both activation of the coagulation system, monitored by the plasma levels of thrombin-antithrombin III complexes, and activation of the fibrinolytic system (plasma levels of tissue-type plasminogen activator, and plasminogen activator inhibitor type I), were of similar magnitude after intravenous injection of wild type TNF or the TNF mutant with affinity only for the p55 receptor. Likewise, wild type TNF and the TNF p55 specific mutant were equally potent in inducing neutrophil degranulation (plasma levels of elastase-alpha 1-antitrypsin complexes). Wild type TNF tended to be a more potent inducer of secretory phospholipase A2 release than the p55 specific TNF mutant. Administration of the TNF mutant binding only to the p75 receptor did not induce any of these responses. We conclude that TNF-Induced stimulation of coagulation, fibrinolysis, neutrophil degranulation, and release of secretory phospholipase A2 are predominantly mediated by the p55 TNF receptor.
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PMID:Tumor necrosis factor-alpha induces activation of coagulation and fibrinolysis in baboons through an exclusive effect on the p55 receptor. 870 50

Tumor necrosis factor-alpha (TNF alpha) is a central mediator in the pathogenesis of sepsis. It also interferes with the hemostatic system and exerts and a net procoagulant effect. Since TNF alpha may contribute to thrombotic complications in sepsis patients, we determined markers of thrombin activation, parameters of the fibrinolytic system (D-dimer, tissue plasminogen activator antigen (tPA) urinary type plasminogen activator antigen (uPA), plasminogen activator inhibitor antigen (PAI-1) and von Willebrand factor antigen (vWF) in 30 patients with sepsis or septic shock. All patients were treated with standard therapy, but 14 patients were treated additionally with an anti-TNF alpha monoclonal antibody (MAK 195F); 16 patients served as historical controls. No significant effect of the antibody on the parameters of the hemostatic system could be determined. Our data speak against a modulation of coagulation or the fibrinolytic system by the monoclonal anti-TNF alpha antibody MAK 195F in this cohort of sepsis patients.
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PMID:Hemostatic parameters in sepsis patients treated with anti-TNF alpha-monoclonal antibodies. 890 37

Tumor necrosis factor-alpha (TNF-alpha) level, tissue-typed plasminogen activator(t-PA) activity and PA inhibitor (PAI) activity were determined in three groups: (1) 25 NIDDM patients with silent myocardial ischemia (SMI) or silent cerebral ischemia (SCI); (2) 18NIDDM patients without SMI or SCI; (3) 20 age-matched normal controls. Diagnosis of SMI or SCI was based on the finding of ischemic evidence by SPECT of myocardiotomograph or cerebrotomograph. All patients ECG and blood pressure were normal, and they had no history of clinical symptoms and signs of MI or CI. The result showed that the TNF-alpha level and PAI activity in the ischemia group were the highest and the t-PA activity in the ischemia group was the lowest, as compared with those in the other two groups respectively. It suggests that in NIDDM patients who have high TNF-alpha, high PAI activity, low t-PA, and even no symptoms and signs of MI or CI, anticoagulant therapy might be useful to prevent the progression of diabetic macroangiopathies.
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PMID:[Changes of serum TNF-alpha level, t-PA activivty and PAI activity in patients with silent myocardial ischemia or silent cerebral ischemia]. 1068 70

Tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta are potent activators of the transcription factor NF-kappaB, induced during inflammatory conditions. We have previously shown that both secretory and cytosolic phospholipase A(2) (PLA(2)) are involved in TNF-alpha- and IL-1beta-induced NF-kappaB activation. In this study, we have addressed the mechanism of PLA(2) involvement with respect to downstream arachidonic acid (AA) metabolites and the functional coupling between PLA(2)s mediating NF-kappaB activation. We show that in addition to inhibitors of secretory and cytosolic PLA(2)s, 5-lipoxygenase inhibitors attenuate TNF-alpha- and IL-1beta-stimulated NF-kappaB activation. Exogenous addition of leukotriene B(4) (LTB(4)) restored NF-kappaB activation reduced by 5-lipoxygenase inhibitors or an LTB(4) receptor antagonist, thus identifying LTB(4) as a mediator in signaling to NF-kappaB. TNF-alpha- and IL-1beta-induced AA release from cellular membranes was accompanied by phosphorylation of cytosolic PLA(2). Inhibitors of secretory PLA(2) and of 5-lipoxygenase/LTB(4) functionality markedly reduced AA release and nearly completely abolished cytosolic PLA(2) phosphorylation. This demonstrates that secretory PLA(2), through 5-lipoxygenase metabolites, is an essential upstream regulator of cytosolic PLA(2) and AA release. Our results therefore suggest the existence of a functional link between secretory and cytosolic PLA(2) in cytokine-activated keratinocytes, providing a molecular explanation for the participation of both secretory and cytosolic PLA(2) in arachidonic acid signaling and NF-kappaB activation in response to proinflammatory cytokines.
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PMID:Functional coupling between secretory and cytosolic phospholipase A2 modulates tumor necrosis factor-alpha- and interleukin-1beta-induced NF-kappa B activation. 1139 Mar 71

Cystic fibrosis (CF) is characterized by a persistent inflammatory state, which can be secondary to chronic pulmonary infection and may affect vascular endothelium. We measured circulating levels of von Willebrand factor (vWF), tissue-plasminogen activator (t-PA), and P-selectin in 20 CF patients and 20 healthy subjects. vWF, t-PA and P-selectin levels were significantly higher in CF patients. Endothelial perturbation (>2 SD increase in both vWF and t-PA) was present in 65% of CF patients. These patients displayed lower FEV1 values compared to individuals without endothelial perturbation and an inverse correlation between FEV1 and P-selectin levels was observed. Tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels were also increased in CF patients and significant direct correlations were found between TNF-alpha and vWF, t-PA or P-selectin levels. These results indicate that CF patients exhibit signs of endothelial dysfunction/perturbation, which are likely to be related to a persistent inflammatory state due to chronic pulmonary infection, and may play a role in the progression of this disease.
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PMID:Endothelial perturbation in cystic fibrosis. 1177

Tuberculous (TB) pleurisy and parapneumonic effusion (PPE) are common causes of pleural fibrosis. The mechanisms underlying fibrin deposition may be different since involved inflammatory cells are distinct. In this study, we measured various cytokines and fibrinolytic enzymes and compared the differences between the two effusions. PPE was further divided into noncomplicated PPE and complicated PPE/empyema subgroups. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, macrophage inflammatory protein (MIP)-1beta, monocyte chemoattractant protein (MCP)-1, plasminogen activator inhibitor type 1 (PAI-1) and tissue type plasminogen activator (tPA) were measured using enzyme-linked immunosorbent assays. Significantly higher values of PAI-1, PAI-1/tPA ratio, IL-1beta, IL-8 and MIP-1beta and significantly lower values of TNF-alpha, IL-6 and MCP-1 were observed in PPE/empyema than in TB effusions. Compared to noncomplicated PPE, complicated PPE/empyema had significantly higher levels of TNF-alpha, IL-1beta, IL-8 and MIP-1beta. TB pleurisy patients who had higher effusion levels of TNF-alpha, IL-1beta and IL-8 were predisposing to residual pleural thickening. The underlying mechanisms of fibrin formation and deposition between the two effusions studied (PPE/empyema and TB pleurisy) could not be fully explained by the results of the present study. More studies are needed to explore this further.
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PMID:Cytokines and fibrinolytic enzymes in tuberculous and parapneumonic effusions. 1589 10


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