Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent observations describe an increase in platelet aggregability and a decrease in fibrinolytic activity in the early morning hours. To determine whether anticoagulant proteins also show such a circadian variation we measured protein C (PC), protein S (PS), antithrombin (AT) and heparin cofactor-II (HC-II) levels on venous plasma samples taken from 10 healthy men at three-hour intervals throughout a 24-hour period. To investigate the possible temporal mapping of circadian periodicity, we also measured plasma levels of beta-thromboglobulin (beta-TG) as an indicator of platelet activation, and interleukin-6 (IL-6) as one of the possible regulatory factors that drive this rhythm. Blood samples were drawn at 6 a.m., 9 a.m., noon, 3 p.m., 6 p.m., 9 p.m. and midnight. PC, IL-6 and beta-TG were measured by ELISA, PS and AT by latex immune assay and HC-II by chromogenic substrate method. A significant circadian variation was found in PC, PS, AT, beta-TG and IL-6, but not in HC-II levels. PC, PS, IL-6 and beta-TG were at their peaks at 6 a.m., and nadirs at a time from noon to midnight. AT peak was at 6 p.m. and nadir at noon. The regression of PS on IL-6 was significant. Although the fluctuations of PS and AT were within the normal ranges during the day, some PC levels of two subjects were below the lower normal limit (0.70). These data indicate that PC, PS, and AT show a marked circadian periodicity as the other components of the blood coagulation and fibrinolytic system do. The similar trends in plasma concentrations of PC, PS, beta-TG and IL-6 may be coincidental, but could reflect a common regulatory mechanism or an effect on each other. The clinical implications of these physiological changes in coagulation inhibitors and the role of IL-6 in the anticoagulant response deserve further studies.
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PMID:Circadian variations in natural coagulation inhibitors protein C, protein S and antithrombin in healthy men: a possible association with interleukin-6. 1023 41

Inflammatory reactions mediated by cytokines are involved in the pathogenesis of acute stroke. Decrease in circulating levels of protein C (PC) and protein S (PS) induced by inflammatory cytokines has been postulated as a potential mechanism for a procoagulant tendency during acute stroke. The procoagulant state associated with impairments in natural anticoagulants may induce microvascular obstruction leading to a tissue perfusion reduction that worsens cerebral ischemia. Interleukin-6 (IL-6) regulate the synthesis of C4b-binding protein (C4BP), an acute-phase protein that also regulates PS plasma levels. We measured IL-6, C4BP, erythrocyte sedimentation rate (ESR), total and free PS and PC in 44 patients with acute ischemic stroke to determine if IL-6 decreases circulating levels of natural anticoagulants through the C4BP pathway and if these acute changes in natural anticoagulants may have clinical implications. Patients with higher levels of IL-6 had more severe neurologic deficits on admission, greater infarct size, higher levels of acute-phase reactants, and lower levels of free PS. IL-6 was significantly correlated with C4BP, ESR, and free PS levels. PC levels were also lower in the group of patients with greater IL-6, but differences were not statistically significant. No correlations were found between C4BP and natural anticoagulants. Severe neurologic deficit, greater infarct volume, atrial fibrillation, increased levels of inflammatory parameters (ESR and IL-6), and reduced levels of free PS were associated with disabling stroke at 3 months, but only neurologic severity and ESR remained as independent predictors of stroke disability on multiple regression analysis. Inflammatory reactions mediated by IL-6 during the acute phase of stroke influence the modulation of free PS. However, variations in free PS levels do not have implications for clinical outcome in stroke patients. The link between proinflammatory cytokines and free PS in the acute phase of stroke is not related to the C4BP pathway.
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PMID:Interaction between interleukin-6 and the natural anticoagulant system in acute stroke. 1076 81

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by intravascular fibrin formation occurring in the course of a variety of severe diseases. In gram-negative sepsis, endotoxin is the bacterial component eliciting a cascade of tissue factor dependent hypercoagulable reactions mediated by cytokines, including tumor necrosis factor-alpha and interleukin-6. Fibrinolysis is activated in this process by the action of tumor necrosis factor-alpha, but its activity is impaired by the predominant inhibitory effect of plasminogen activator inhibitor-1. Natural inhibitory mechanisms include antithrombin, the protein C system, and tissue factor pathway inhibitor. Each of these defense systems counteracts the harmful effects of DIC, and its acquired deficiency is associated with increased mortality in observational studies. The generation of several proteases in DIC, including factor Xa and thrombin, has potential interactions with inflammatory pathways that may potentiate the systemic inflammatory syndrome that often accompanies DIC. Experimental studies support the notion that defects in the protein C pathway modulate the inflammatory response, and illustrate that coagulation and inflammation are coupled systems in DIC.
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PMID:Pathophysiology of disseminated intravascular coagulation in sepsis. 1100 90

Protection against infection with Borrelia burgdorferi is dependent primarily on induction of complement-dependent antibody that can kill the spirochete. Measuring the production of sustained high levels of borreliacidal antibody is thus paramount for determining potential vaccine efficacy. We investigated the borreliacidal antibody response in sera and the amount of antibody produced by cultured lymph node cells of C3H/HeJ mice vaccinated with outer surface protein C (OspC). We showed that recombinant OspC was a weak stimulant of borreliacidal antibody production compared to whole cells of OspC-expressing B. burgdorferi. Mice vaccinated with B. burgdorferi in adjuvant produced a high level (titer, 5,120) of anti-OspC borreliacidal antibody, which waned rapidly. Similarly, borreliacidal antibody production by cultured lymph node cells from vaccinated mice peaked soon after vaccination and then decreased. Treatment of lymph node cells with interleukin-6 (IL-6) augmented borreliacidal antibody production, particularly immunoglobulin G2b, whereas treatment with anti-IL-6 inhibited the borreliacidal response. These findings demonstrate a previously unrecognized role for IL-6 in borreliacidal antibody production that may have important implications for vaccine development.
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PMID:Interleukin-6 enhances production of anti-OspC immunoglobulin G2b borreliacidal antibody. 1140 63

Drotrecogin alfa (activated), recombinant human activated protein C, inhibits coagulation and inflammation and promotes fibrinolysis in patients with severe sepsis. 850 patients with severe sepsis treated with intravenous drotrecogin alfa (activated) 24 microg/kg/h for 96 hours had a significantly greater reduction in 28-day all-cause mortality (24.7%) than 840 placebo recipients (30.8%) in a randomised, double-blind, placebo-controlled study. The drug was associated with a 19.4% reduction in the relative risk of death at 28 days compared with placebo. Baseline characteristics of and pre-existing conditions in patients with sepsis appeared to have no effect on the efficacy of drotrecogin alfa (activated). A significantly greater reduction in median percentage change from baseline plasma D-dimer levels (a coagulation marker) was seen with drotrecogin alfa (activated) treatment than with placebo on study days 1 to 7 in patients with severe sepsis. On study days 1, 4, 5, 6 and 7, a significantly greater median reduction in interleukin-6 levels (an inflammation marker) from baseline was seen with drotrecogin alfa (activated) treatment than placebo. Drotrecogin alfa (activated) was associated with an increased incidence of serious bleeding events during the infusion period [2.4% vs 1.0% with placebo; p = 0.024] and the 28-day study period (3.5 vs 2.0%; p = 0.06) of the efficacy trial. This increase was primarily related to procedure-related events; there were no significant differences between the treatment groups in nonprocedure-related serious bleeding events. The most frequent site of bleeding was the gastrointestinal tract. With the exception of bleeding events, there were no clinically significant differences between treatment groups in the efficacy trial in the incidence of adverse events. Of the 210 deaths in patients with severe sepsis treated with drotrecogin alfa (activated) 24 microg/kg/h in the efficacy trial, four deaths due to haemorrhage and one due to cerebral oedema were possibly related to the study drug.
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PMID:Drotrecogin alfa (activated). 1189 30

Abnormalities in coagulation and haemostasis represent a well-known link between obesity and thrombosis (both arterial and venous). Several studies have shown that obese patients have higher plasma concentrations of all pro-thrombotic factors (fibrinogen, vonWillebrand factor (vWF), and factor VII), as compared to non-obese controls, with a positive association with central fat. Similarly, plasma concentrations of plasminogen activator inhibitor-1 (PAI-1) have been shown to be higher in obese patients as compared to non-obese controls and to be directly correlated with visceral fat. Furthermore, obesity is characterized by higher plasma concentrations of anti-thrombotic factors, such as tissue-type plasminogen activator (t-PA) and protein C, as compared to non-obese controls, the increase in these factors being likely to represent a protective response partly counteracting the increase in pro-thrombotic factors. The issue of whether adipose tissue contributes directly to plasma PAI-1, its products stimulating other cells to produce PAI-1, or whether it primarily contributes indirectly has not yet been resolved. It has been proposed that the secretion of interleukin-6 (IL-6) by adipose tissue, combined with the actions of adipose tissue-expressed TNF-alpha in obesity, could underlie the association of insulin resistance with endothelial dysfunction, coagulopathy, and coronary heart disease. The role of leptin in impairing haemostasis and promoting thrombosis has been recently reported. Finally, some hormonal abnormalities (androgen, F, catecholamines) associated with the accumulation of body fat may contribute to the impairment of coagulative pathway in obesity. As to intervention strategies, dietary (i.e., low-fat high-fiber diet) and lifestyle (i.e., physical activity) measures have been demonstrated to be effective in improving the obesity-associated pro-thrombotic risk profile.
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PMID:Coagulation and fibrinolysis abnormalities in obesity. 1250 53

In the pathogenesis of sepsis and disseminated intravascular coagulation (DIC), dysfunctional anticoagulant pathways are important. The function of the protein C system in DIC is impaired because of low levels of protein C and down-regulation of thrombomodulin. The administration of (activated) protein C results in an improved outcome in experimental and clinical studies of DIC. It is unknown whether congenital deficiencies in the protein C system are associated with more severe DIC. The aim of the present study was to investigate the effect of a heterozygous deficiency of protein C on experimental DIC in mice. Mice with single-allele targeted disruption of the protein C gene (PC+/-) mice and wild-type littermates (PC+/+) were injected with Escherichia coli endotoxin (50 mg/kg) intraperitoneally. PC+/-mice had more severe DIC, as evidenced by a greater decrease in fibrinogen level and a larger drop in platelet count. Histologic examination showed more fibrin deposition in lungs, kidneys, and liver in mice with a heterozygous deficiency of protein C. Interestingly, PC+/- mice had significantly higher levels of proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1beta, indicating an interaction between the protein C system and the inflammatory response. Survival was lower at 12 and 24 hours after endotoxin in the PC+/- mice. These results confirm the important role of the protein C system in the coagulative-inflammatory response on endotoxemia and may suggest that congenital deficiencies in the protein C system are associated with more severe DIC and adverse outcome in sepsis.
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PMID:Aggravation of endotoxin-induced disseminated intravascular coagulation and cytokine activation in heterozygous protein-C-deficient mice. 1260 41

The protein C anticoagulant pathway serves as a major system for controlling thrombosis, limiting inflammatory responses, and potentially decreasing endothelial cell apoptosis in response to inflammatory cytokines and ischemia. The essential components of the pathway involve thrombin, thrombomodulin, the endothelial cell protein C receptor (EPCR), protein C, and protein S. Thrombomodulin binds thrombin, directly inhibiting its clotting and cell activation potential while at the same time augmenting protein C (and thrombin activatable fibrinolysis inhibitor [TAFI]) activation. Furthermore, thrombin bound to thrombomodulin is inactivated by plasma protease inhibitors > 20 times faster than free thrombin, resulting in increased clearance of thrombin from the circulation. The inhibited thrombin rapidly dissociates from thrombomodulin, regenerating the anticoagulant surface. Thrombomodulin also has direct anti-inflammatory activity, minimizing cytokine formation in the endothelium and decreasing leukocyte-endothelial cell adhesion. EPCR augments protein C activation approximately 20-fold in vivo by binding protein C and presenting it to the thrombin-thrombomodulin activation complex. Activated protein C (APC) retains its ability to bind EPCR, and this complex appears to be involved in some of the cellular signaling mechanisms that down-regulate inflammatory cytokine formation (tumor necrosis factor, interleukin-6). Once APC dissociates from EPCR, it binds to protein S on appropriate cell surfaces where it inactivates factors Va and VIIIa, thereby inhibiting further thrombin generation. Clinical studies reveal that deficiencies of protein C lead to microvascular thrombosis (purpura fulminans). During severe sepsis, a combination of protein C consumption, protein S inactivation, and reduction in activity of the activation complex by oxidation, cytokine-mediated down-regulation, and proteolytic release of the activation components sets in motion conditions that would favor an acquired defect in the protein C pathway, which in turn favors microvascular thrombosis, increased leukocyte adhesion, and increased cytokine formation. APC has been shown clinically to protect patients with severe sepsis. Protein C and thrombomodulin are in early stage clinical trials for this disease, and each has distinct potential advantages and disadvantages relative to APC.
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PMID:The protein C pathway. 1297 Jan 21

Drotrecogin alfa (activated) improved survival in patients with severe sepsis in PROWESS, a double-blind, study of 1690 adult patients randomized to drotrecogin alfa (activated) at 24 microg/kg/h (N=850) or placebo (N=840) infused for 96 hours. Pharmacodynamic effects of drotrecogin alfa (activated) were assessed with 15 prospectively defined systemic biomarkers of hemostasis, inflammation and endothelial injury. The last-observation-carried-forward (LOCF) method of imputation for missing observations was the prospectively defined statistical method. The results were also analyzed with only the observed values without imputation for missing data (repeated measures analysis). With both statistical methods, drotrecogin alfa (activated)-treated patients demonstrated antithrombotic (reduced markers of thrombin generation and accelerated normalization of anticoagulant factor, protein C and fibrinolytic factors) and anticoagulant (prolonged PT and APTT) effects compared with placebo. A profibrinolytic (reduction in plasminogen activator inhibitor-1) effect was significant only with the LOCF imputation method in observed case and percent change from baseline analyses. An anti-inflammatory (reduction in interleukin-6) effect was significant only with the LOCF imputation method in change from baseline and percent change from baseline analyses. Drotrecogin alfa (activated) is a new and promising agent for treatment of patients with severe sepsis. The extensive analysis of systemic biomarkers confirms the previously published antithrombotic effects. However, the present results using different statistical methods do not provide a strong basis for systemic anti-inflammatory or pro-fibrinolytic effects. These latter two effects may occur at the local or cellular level. The systemic biomarkers reported here might not be the most appropriate approach to demonstrate these potential effects of drotrecogin alfa (activated).
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PMID:Drotrecogin alfa (activated) (recombinant human activated protein C) reduces host coagulopathy response in patients with severe sepsis. 1511 70

The effects of n-acetyl cysteine (NAC), s-allyl cysteine (SAC), s-ethyl cysteine, s-methyl cysteine and s-propyl cysteine (SPC) activity on Balb/cA mice against diabetic complications were examined. These complications included hyperglycemia, hyperlipidemia, oxidation stress, blood coagulation, and cytokine imbalance. To induce diabetes, mice were treated with streptozotocin i.p. for 5 consecutive days. Five cysteine-containing compounds at 1 g/L were added to the drinking water. After intake of the 5 cysteine-containing agents for 4 wk, body weight loss, plasma concentrations of glucose and insulin, and fibronectin levels were improved (P < 0.05) in diabetic mice. The administration of these agents restored the glutathione level (P < 0.05), reduced the loss of catalase and glutathione peroxidase activities in kidney and liver (P < 0.05), and decreased glucose-induced lipid oxidation, as assessed by malondialdehyde formation (P < 0.05). In all diabetic mice, the intake of these agents reduced triglyceride levels in plasma and liver (P < 0.05); however, only NAC, SAC and SPC treatments reduced cholesterol level in liver (P < 0.05). These cysteine-containing agents elevated the activity of 2 fibrinolytic factors, protein C and antithrombin III (P < 0.05). The overexpression of interleukin-6 and tumor necrosis factor-alpha in diabetic mice was suppressed by the intake of the 5 cysteine-containing agents (P < 0.05). Via their antioxidant activities, the 5 compounds effectively improved glycemic control, delayed oxidation damage, downregulated inflammatory cytokines, and enhanced anticoagulant activity in diabetic mice. These data support the multiple roles of these agents as potential protective agents for delaying diabetic deterioration.
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PMID:Five cysteine-containing compounds delay diabetic deterioration in Balb/cA mice. 1557 20


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