Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antithrombin III (ATIII) and protein C (PC) are major inhibitors of the coagulation cascade and might regulate the cytokine network. We tested the possibility that a combined supplementation using these two inhibitors might have synergistic effects on sepsis-induced disseminated intravascular coagulation and shock. Hemodynamics, coagulation parameters, tumor necrosis factor (TNF) alpha, and interleukin 6 levels were measured in pigs submitted to a bolus infusion of Escherichia coli endotoxin (lipopolysaccharide). Four groups were studied: control lipopolysaccharide, ATIII (100 IU/kg), PC (50 IU/kg), and ATIII-PC (same doses). The endotoxin infusion resulted in a typical hypokinetic shock with disseminated intravascular coagulation in all animals. Compared with the control group, a significant improvement in mean arterial pressure and systemic vascular resistance was observed in the PC and ATIII-PC groups. The increase in lactate levels was almost completely blunted in the PC group. A significant lesser increase in TNFalpha levels was observed in the ATIII-PC group. No effects were seen on interleukin 6 levels. Coagulation and fibrinolysis parameters were not improved by ATIII and/or PC, except for a lesser decrease in prothrombin time in the ATIII-PC group. We conclude that in this acute endotoxic model, a combined supplementation using PC and ATIII concentrates has favorable effects on hemodynamic parameters and TNFalpha levels, independently from the anticoagulant actions of these inhibitors.
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PMID:Effects of a combined antithrombin III and protein C supplementation in porcine acute endotoxic shock. 984 Jun 53

During severe sepsis there is dramatic activation of both contact proteases and the coagulation pathway. These processes contribute to the development of shock and disseminated intravascular coagulation (DIC) respectively. The Pittsburgh mutant of antitrypsin (358Met-Arg) is a novel protease inhibitor with activity against both thrombin and the contact proteases and should therefore prove beneficial as a therapeutic agent in the management of septic shock. This hypothesis was supported by an earlier study in a pig model where recombinant antitrypsin Pittsburgh (rAT Pittsburgh) at a concentration of 1 microM alleviated some of the features of shock, but did not improve survival. In order to reduce the lethal effects of E. coli sepsis we postulated that a higher concentration of antitrypsin Pittsburgh would be necessary. To test this hypothesis we used rAT Pittsburgh in a primate model. This was chosen in preference to another species as E. coli sepsis in the primate has been well characterised and closely resembles the changes seen in man. Surprisingly this treatment did not alleviate the features of shock and unexpectedly appeared to exacerbate the associated coagulopathy. We propose two possible mechanisms for this unforeseen outcome. The first results from the broad spectrum of activity of antitrypsin Pittsburgh. As well as inhibiting thrombin and the contact proteases, the Pittsburgh mutant also inhibits activated protein C. Inhibition of the protein C system is known to exacerbate septic shock. Secondly, a significant quantity of inactive antitrypsin Pittsburgh, cleaved at the reactive centre, was detected in the plasma of the treated animals. Proteolytically altered serpins, including antitrypsin. have been shown to enhance the inflammatory process. Therefore the accumulation of cleaved rAT Pittsburgh might be expected to exacerbate septic shock.
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PMID:Recombinant antitrypsin Pittsburgh undergoes proteolytic cleavage during E. coli sepsis and fails to prevent the associated coagulopathy in a primate model. 984 77

Bacteroides fragilis, a Gram-negative colonic bacterium, induces the formation of abscesses associated with intra-abdominal sepsis in humans. The singular ability of this organism to modulate abscess formation in experimental rodent models resides in the structurally distinct and ionically charged capsular polysaccharides A (PS A) and B (PS B). The regulation of abscess formation in animals is dependent on T lymphocytes. However, the manner in which PS A interacts with T cells remains unknown. We therefore tested the T cell stimulatory capacity of purified PS A on mouse and rat lymphocytes in cellular proliferation assays and found that the PS A molecule possesses mitogenic characteristics distinguishable from those of the polyclonal B cell activator LPS, the T cell mitogen Con A, and staphylococcal enterotoxin A superantigen. Further, PS A stimulated proliferation of normal mouse and rat lymphocytes differentially. Mouse B cells responded to PS A in a fashion that did not require exogenous APC function, while rat T lymphocyte responses to PS A required APC function derived from autologous or xenogenic feeder cells. Cellular depletion experiments showed that the CD4+ subset of rat spleen cells was the primary responder cell type to PS A in vitro. The differential stimulatory effects of PS A on mouse and rat lymphocytes may reflect its ability to stimulate different lymphocyte subsets in vivo through the activities of receptor/counter-receptor pairs present on responder lymphocytes and cognate APC.
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PMID:Mitogenic activity of purified capsular polysaccharide A from Bacteroides fragilis: differential stimulatory effect on mouse and rat lymphocytes in vitro. 997 99

In order to determine the effect of bacterial proteinases on activation of the protein C system, a negative regulator of blood coagulation, two arginine-specific cysteine proteinases (gingipains R) from Porphyromonas gingivalis, a causative bacterium of adult periodontitis, were examined. Each enzyme activated human protein C in a dose- and incubation time-dependent manner. Interestingly, the form of enzyme being composed of a non-covalent complex containing both catalytic and adhesion domains (RgpA) produced activated protein C 14-fold more efficiently than RgpB which contained the catalytic domain alone. The kcat/Km value of RgpA was 18-fold higher than that of RgpB and comparable to that of the thrombin-thrombomodulin complex, the physiological activator of protein C. RgpA catalyzed protein C activation was augmented 1.4-fold by phospholipids, ubiquitous cell membrane components. Furthermore, RgpA, but not RgpB, could activate protein C in plasma and this resulted in a decrease of the protein C concentration in plasma, which is often observed in patients with sepsis during the development of disseminated intravascular coagulation (DIC). These data indicate that RgpA is a more potent activator of protein C than RgpB and suggest that only the former enzyme can cause protein C activation in vivo. The present study further suggests that bacterial proteinases may possibly contribute to the consumption of plasma protein C which predisposes to DIC and/or promotes a thrombotic tendency towards DIC in sepsis.
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PMID:Activation of protein C by arginine-specific cysteine proteinases (gingipains-R) from Porphyromonas gingivalis. 1006 39

The protein C pathway plays a critical role in the negative regulation of the blood clotting process. We recently identified an endothelial cell receptor for protein C/activated protein C (APC). The receptor is localized almost exclusively on endothelial cells of large vessels and is present at only trace levels or indeed absent from capillaries in most tissues. Patients with sepsis or lupus erythematosus exhibit elevated levels of plasma EPCR which migrates on gels as a single band and is fully capable of binding protein C/APC. There is no correlation with thrombomodulin levels, probably due to different vascular localizations and/or cellular release mechanisms. To understand the mechanisms by which EPCR plasma levels are elevated, we examined EPCR mRNA expression in a rat endotoxin shock model. The EPCR mRNA gene exhibited an early immediate gene response to endotoxin with the mRNA levels increasing nearly 4 fold in the first 3-6 hrs, before returning toward baseline. Plasma levels of EPCR also rose about 4 fold with little change in tissue EPCR levels. Both processes were markedly attenuated by hirudin suggesting that thrombin was responsible for increases in mRNA and plasma EPCR levels. At the level of mRNA, the induction is mediated by a thrombin response element in the 5' flanking region of the gene. Direct thrombin infusion and cell culture experiments support this contention. On endothelium, thrombin is capable of releasing cell surface EPCR and this process is blocked by the metalloproteinase inhibitor orthophenanthroline. Taken together these studies indicate that elevation in soluble plasma EPCR reflects endothelial cell activation in the larger vessels and is likely to be an indication of local thrombin generation near these vessel surfaces.
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PMID:Regulation and functions of the protein C anticoagulant pathway. 1019 Sep 52

Sepsis is a frequent complication of critically ill patients and its incidence is increasing. Currently, septic shock is the most common cause of death in non-coronary intensive care units. Over the last 10 to 15 years, new antibiotics and increasingly sophisticated critical care have had little impact on the mortality rate of septic shock. The Italian SEPSIS Study, carried out in 99 intensive care units in 1994, reported mortality rates of 52% and 82% for severe sepsis and septic shock respectively. New therapeutic approaches aimed at neutralizing microbial toxins and modulating host mediators have shown some efficacy in large clinical trials and/or in animal models, but to date, no therapy of sepsis aimed at reversing the effects of bacterial toxins or of harmful endogenous mediators of inflammation has gained widespread clinical acceptance. Because of the strong association of severe sepsis with a state of activation of blood coagulation and of the potential role of capillary thrombosis in the development of the multiple organ dysfunction syndrome, anticoagulant agents have been tested in the setting of septic shock. However, neither administration of heparin nor of active site-blocked factor Xa or of anti-tissue factor antibodies have proven effective in preventing deaths due to septic shock in animal models. In contrast, infusion of antithrombin, protein C, or tissue factor pathway inhibitor all resulted in a significant survival advantage in animals receiving lethal doses of E. Coli. Antithrombin concentrates have been used in a significant number of critically ill patients. A double-blind, placebo controlled study carried out in 3 italian intensive care units has recently shown that the administration of antithrombin aimed to normalize plasma antithrombin activity had a net beneficial effect on 30-day survival of patients requiring respiratory and/or hemodynamic support because of severe sepsis and/or post-surgery complications.
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PMID:Antithrombin replacement in patients with sepsis and septic shock. 1032 25

Under normal conditions activated protein C is a natural anticoagulant that cleaves 2 activated coagulation factors, factor Va and factor VIIIa, thereby inhibiting the conversion of factor X to factor Xa and of prothrombin to thrombin. Additionally, activated protein C enhances tissue-plasminogen activator-mediated fibrinolysis by inhibition of plasminogen activator inhibitor-1. This results in an increase in circulatory plasminogen activator levels. Protein C deficiency, a genetic or acquired thrombophilic abnormality, has been demonstrated to predispose to episodes of potentially blinding and lethal thromboembolic events. Heterozygous-deficient subjects usually remain asymptomatic until adolescence or adulthood. In homozygous-deficient patients, protein C activity is usually less than 1% (reference range, 70%-140%), resulting in thromboembolism as early as in the neonatal period. The major clinical symptoms in affected newborn infants have been purpura fulminans, vitreous hemorrhage, and central nervous system thrombosis. The age of onset of the first symptoms has ranged from a few hours to 2 weeks after birth, usually after an uncomplicated full-term pregnancy and delivery. In contrast to the genetic form, acquired neonatal protein C deficiency occurs particularly in ill preterm babies. Typical complications of prematurity such as respiratory distress syndrome, necrotizing enterocolitis, and neonatal sepsis may also be present. In the medical literature, there are only a few reports of homozygous protein C deficiency in neonates. We present 2 cases of homozygous protein C deficiency with ocular and extraocular manifestation.
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PMID:Ophthalmic manifestation of congenital protein C deficiency. 1042 94

Increased levels of the acute phase protein C-reactive protein (CRP) in plasma may indicate severe acute abdominal disease, risk of serious postoperative complications or malignancy; serial measurements may indicate postoperative complications, relapse of intra-abdominal sepsis and complications during acute pancreatitis. The increase in CRP is an unspecific acute phase reaction, however, and low levels do not exclude these conditions. These facts are important obstacles to the clinical routine use of CRP measurements. The aim of this study was to look for possible biochemical microheterogeneity of CRP in single plasma samples from various large groups of patients to overcome these problems. Two-hundred-and-twelve patients with acute abdominal diseases, 274 patients with various forms and stages of cancer and 134 patients operated on due to benign diseases, were studied. The biochemical studies included SDS-PAGE, native PAGE and gel filtration for molecular weight determinations, isoelectric focusing and crossed immuno-electrophoresis for electrophoretic mobility studies and Concavalin A and ACA 34 as intermediary gels for possible lectin binding or complexation. Western blot analysis was also used to identify CRP. In summary, however, these more elaborate biochemical methods could not disclose any microheterogneity of CRP in plasma and thus did not add any diagnostic information to the crude levels.
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PMID:No microheterogenous changes of plasma C-reactive protein found in man during various diseases. 1046 68

Several therapeutic approaches to sepsis and disseminated intravascular coagulation (DIC) have shown promising results in animal models. Large controlled trials in humans, however, have failed to show a clearly beneficial effect of a single drug or substance on outcome and survival so that treatment remains uncertain. As one researcher stated: ". . . sepsis is a classical example of a disease greater than the sum of its parts; it is a complex process in which intervention in one area might have only a modest effect on the final outcome." We believe that the complex pathophysiological setting of septic shock will undoubtedly require a multifaceted approach. Consequently, we attempt to arrest DIC and restore adequate tissue perfusion by intervention with heparin, AT and if possible protein C (PC) in the earliest stage of the disease, with the aim of blocking ongoing microthrombus formation and to support fibrinolysis. Growing understanding of the basic underlying mechanisms teaches us how to successfully stabilise the individual decompensated sub-systems like coagulation in septic patients. We should learn to accept these steps to reach the goal of a better outcome in terms of survival in this devastating illness.
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PMID:Neonatal sepsis: a challenge in hemostaseology. 1063 74

We report the effects of substitution with a virus-inactivated protein C (PC) concentrate in disseminated intravascular coagulation (DIC) in infants and children with meningococcal sepsis associated with purpura fulminans. It was a prospective open-label study. Eight pediatric and adolescent patients age 0.2 to 18.25 years with DIC associated with severe acquired PC deficiency (range 0.02 to 0.48 IU/mL; median, 0.22 IU/mL) in meningococcal septic shock and purpura fulminans were studied. Replacement therapy was initiated with a virus-inactivated PC concentrate with an initial intravenous bolus of 80 to 120 IU/kg followed by 50 IU/kg up to six times per day as an adjunctive therapeutic regimen to otherwise optimal intensive care treatment. After initial PC administration, plasma PC levels rose to normal ranges and were maintained under PC replacement therapy. Improving or even normalizing global hemostatic parameters were assessed in all patients. Markedly elevated plasminogen activator inhibitor type 1 (PAI-1) levels prior to treatment, reflecting a reduced fibrinolytic potential, decreased rapidly under PC substitution. Concomitantly improving signs of purpura fulminans reflected by decreasing size of skin lesions, demonstrated a restoring microcirculation. Six of the eight patients survived. One patient required limb amputation; two patients died because of multiorgan failure. Both presented with a severely low plasma PC activity of 0.02 IU/mL on admission to the hospital. No adverse effects were observed with the PC concentrate administration. It can be concluded that the administration of PC concentrate had a marked benefit on the deranged coagulation status of patients with purpura fulminans and meningococcal septicemia. Normalization or even partial correction of hemostasis as well as improvement of microcirculation accompanied by improving signs of purpura fulminans were demonstrated in all patients.
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PMID:Replacement therapy with protein C concentrate in infants and adolescents with meningococcal sepsis and purpura fulminans. 1063 75


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