An enhanced fibrinolysis prevents the development of multiple organ failure in disseminated intravascular coagulation in spite of much activation of blood coagulation

OBJECTIVES: To investigate the relationship between fibrinolytic enhancement and the development of multiple organ failure (MOF) in disseminated intravascular coagulation (DIC). To detect the useful prognostic index for outcome in DIC. DESIGN: Case-control study. SETTING: A department of internal medicine in a university hospital, a clinical division for diagnosis and treatment, mainly of respiratory diseases, hematologic diseases, DIC, and other diseases requiring critical care medicine. PATIENTS: A total of 69 DIC patients, 31 with MOF. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: The DIC patients with MOF had more elevated levels of tissue plasminogen activator antigen (t-PA) and plasminogen activator inhibitor antigen (PAI), and more depressed levels of plasmin-alpha2 plasmin inhibitor complex (PIC) and fibrin/fibrinogen degradation products than those without MOF, although no significant difference in thrombin-antithrombin complex (TAT) levels was observed. A fibrinolytic enhancement (shown by PIC) was parallel to an activation of blood coagulation (shown by TAT) in DIC patients without MOF, although no such fibrinolytic enhancement was provoked even by much activation of blood coagulation in DIC patients with MOF. Whereas all the patients without MOF were restored from DIC, 14 of 31 patients with MOF were unable to be restored from DIC and died. A significant increase in plasma levels of t-PA and PAI under the condition of sustained hemostatic activation was observed in the patients who died. CONCLUSION: Enhanced fibrinolysis was considered to be the important defense mechanism in preventing the development of MOF in DIC. The increases in plasma levels of t-PA and PAI were poor prognostic markers in DIC. Further careful study may be useful to clarify whether the fibrinolytic therapy is beneficial in clinical DIC patients with MOF.     

The hyperfibrinolytic state of liver cirrhosis: possible pathogenetic role of ascites

We evaluated coagulation and fibrinolytic parameters in both plasma and ascitic fluid of 39 patients with ascites secondary to liver cirrhosis and in 14 cirrhotic patients without ascites, in order to verify if the peritoneal compartment could be involved in the pathogenesis of the hyperfibrinolytic state of the disease. An activation of fibrinolysis, as suggested by increased levels of FDP, D-dimer and tissue plasminogen activator (t-PA) was demonstrated in both ascitic fluid and to a lesser extent in plasma. A positive correlation was also observed between plasma and ascitic fluid plasminogen, antiplasmin and fibrinogen, while a negative correlation was found between plasma and ascitic fluid plasminogen activator inhibitor-1 (PAI-1). Moreover, plasma PAI-1 was significantly lower in patients with ascites than in those without ascites and among ascitic patients in those who had bleeding into soft tissues when compared to those who did not present haemorrhagic events. Finally, a significant association was also shown between positivity for plasma D-dimer (> 200 ng/ml) and the presence of ascites. Taken together, our data suggest an exchange of some coagulation and fibrinolytic proteins between plasma and ascitic fluid and point out the key role of PAI-1 in regulating plasma fibrinolytic potential and in bleeding complications in cirrhotic patients.     

Tissue plasminogen activator antigen and activity in disseminated intravascular coagulation: clinicopathologic correlations

The fibrinolytic response to disseminated intravascular coagulation (DIC) has been considered important both in preventing thrombosis and in contributing to hemorrhage. Detailed studies of fibrinolysis in DIC are lacking, however. We measured tissue plasminogen activator (t-PA) antigen and activity levels in 74 patients with DIC, 53 hospitalized patients with similar illnesses without DIC, and 36 healthy normal subjects, using sensitive, specific assays. Mean t-PA antigen levels were significantly higher in patients with DIC than in either hospitalized control subjects or normal individuals in most disease categories studied. Highest t-PA antigen levels were seen in patients with liver disease, but patients with DIC without liver disease also had significantly elevated t-PA antigen. Detectable free t-PA activity was infrequently seen in patients with DIC, however. No correlation was found with either thrombotic or hemorrhagic complications and levels of t-PA antigen or activity in DIC, with the possible exception of increased t-PA activity in two patients with intracranial hemorrhage. Bleeding complications were seen almost exclusively in patients with underlying anatomic lesions, and thrombotic complications were usually associated with other known predisposing factors. We conclude that t-PA antigen is usually elevated in DIC, but free t-PA activity is infrequently seen, most likely because of increased levels of t-PA inhibitor. The presence or absence of free t-PA activity does not appear to predict which patients with DIC will develop hemorrhage or thrombosis.     

Generation in plasma of a fast-acting inhibitor of plasminogen activator in response to endotoxin stimulation.

Endotoxin producing bacteria cause disseminated intravascular coagulation (DIC); however, the mechanism of endotoxin action in man is still unclear. Impairment of the fibrinolytic system has been suggested as a contributing mechanism. A single injection of Escherichia coli lipopolysaccharide in rabbits resulted in a marked and prolonged increase of the levels of a fast-acting inhibitor of plasminogen activator (PA-inhibitor) in plasma (from 3.9 +/- 0.7 to 41 +/- 13.2 U/ml after 3 h). Gel filtration studies indicated that inhibition of human tissue-type plasminogen activator (t-PA) by rabbit plasma is accompanied by a change in the elution profile of the activator compatible with the formation of an enzyme-inhibitor complex with an apparent molecular weight of 100,000. Injection of human t-PA (1,500 IU/kg body wt) in endotoxin treated animals resulted in very fast inhibition of t-PA and formation of a similar complex. The half-life of circulating PA-inhibitor activity in rabbits was about 7 min as estimated by donor receiver plasma transfusion experiments. Stimulation of cultured human endothelial cells with endotoxin resulted in enhanced rate of accumulation of PA-inhibitor activity in the culture medium (two- to sevenfold increase). In five patients with septicemia, markedly increased levels of PA-inhibitor (14.3 +/- 15.5 U/ml) as compared with control subjects (1.3 +/- 0.7 U/ml) were observed in plasma. A very strong correlation (r = 0.98) was found between inhibition of t-PA and of urokinase in all conditions, suggesting that this fast-acting inhibitor reacts with both plasminogen activators. These data suggest that the appearance of this fast-acting PA-inhibitor is very sensitive to endotoxin stimulation. The marked increase in the level of PA-inhibitor in blood may contribute to the pathogenesis of DIC in septicemia.     

Combination of thrombin-antithrombin complex,plasminogen activator inhibitor-1, and protein C activity for early identification of severe coagulopathy in initial phase of sepsis: a prospective observational study

Introduction

Current criteria for early diagnosis of coagulopathy in sepsis are limited. We postulated that coagulopathy is already complicated with sepsis in the initial phase, and severe coagulopathy or disseminated intravascular coagulation (DIC) becomes overt after progressive consumption of platelet and coagulation factors. To determine early diagnostic markers for severe coagulopathy, we evaluated plasma biomarkers for association with subsequent development of overt DIC in patients with sepsis.

Methods

A single-center, prospective observational study was conducted in an adult ICU at a university hospital. Plasma samples were obtained from patients with sepsis at ICU admission. Fourteen biomarkers including global markers (platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen and fibrin degradation product (FDP)); markers of thrombin generation (thrombin-antithrombin complex (TAT) and soluble fibrin); markers of anticoagulants (protein C (PC) and antithrombin); markers of fibrinolysis (plasminogen, α₂-plasmin inhibitor (PI), plasmin-α₂-PI complex, and plasminogen activator inhibitor (PAI)-1); and a marker of endothelial activation (soluble E-selectin) were assayed. Patients who had overt DIC at baseline were excluded, and the remaining patients were followed for development of overt DIC in 5 days, and for mortality in 28 days.

Results

A total of 77 patients were enrolled, and 37 developed overt DIC within the following 5 days. Most patients demonstrated hemostatic abnormalities at baseline with 98.7% TAT, 97.4% FDP and 88.3% PC. Most hemostatic biomarkers at baseline were significantly associated with subsequent development of overt DIC. Notably, TAT, PAI-1 and PC discriminated well between patients with and without developing overt DIC (area under the receiver operating characteristic curve (AUROC), 0.77 (95% confidence interval, 0.64 to 0.86); 0.87 (0.78 to 0.92); 0.85 (0.76 to 0.91), respectively), and using the three together, significantly improved the AUROC up to 0.95 (vs. TAT, PAI-1, and PC). Among the significant diagnostic markers for overt DIC, TAT and PAI-1 were also good predictors of 28-day mortality (AUROC, 0.77 and 0.81, respectively).

Conclusions

Severe coagulation and fibrinolytic abnormalities on ICU admission were associated with subsequent development of overt DIC. A single measurement of TAT, PAI-1, and PC activity could identify patients with ongoing severe coagulopathy, early in the course of sepsis.     

大鼠失血性休克继发凝血活化的实验治疗

为了探讨不同复苏液对失血性休克大鼠凝血功能的影响和可能机制,将50只SD大鼠随机分为5组：对照组、假手术组、休克组、复苏1组（输林格液）和复苏2组（输林格液＋万汶液）,每组10只大鼠。建立失血性休克大鼠模型后,复苏组在失血性休克1小时后给予不同复苏液（林格液、6%中分子羟乙基淀粉130/0.4即万汶液）,复苏2小时后采血,检测血浆组织型纤溶酶原激活剂（t-PA）、组织型纤溶酶原激活剂抑制物-1（PAI-1）、组织因子（TF）的变化。研究结果表明：与对照组、假手术组比较,休克组和复苏1组的t-PA、t-PA/PAI-1、TF水平均明显升高（P〈0.01）;复苏1组t-PA、t-PA/PAI-1水平明显高于休克组（P〈0.01）;而复苏2组t-PA、t-PA/PAI-1、TF均明显低于休克组和复苏1组（P〈0.01）。结论：大鼠失血性休克可使纤溶功能亢进,血小板和凝血系统被活化;采用万汶液加林格液复苏在调节凝血功能方面优于单用林格液。     

Time sequence of coagulation data in patients with decompensated liver cirrhosis and suspected disseminated intravascular coagulation

In patients with liver cirrhosis, especially in the advanced stage, the coexistence of low clotting factor levels, hypofibrinogenemia, thrombocytopenia and elevated fibrin(ogen) degradation product (FDP) and D-dimer levels may suggest the presence of disseminated intravascular coagulation (DIC). In this study we evaluated, in 21 patients with decompensated liver cirrhosis and elevated FDP and D-dimer levels, the time sequence of their coagulation data during a follow-up period of 15 days after the first observation; our aim was to clarify if these patients tend to develop during this time interval a severe consumption coagulopathy as an expression of overt DIC. We evaluated serum fibrinogen, platelet count, prothrombin activity, serum FDP and plasma D-dimer levels at days 1, 3, 6, 10 and 15. The coagulation data were fairly stable during the study period in all patients, even in the two patients who had upper digestive tract bleeding during the study time. Only two patients affected by infectious diseases showed a decrease of D-dimer and FDP levels after healing. Our data suggest that in decompensated liver cirrhosis the detection of elevated FDP and D-dimer levels is seldom related to the occurrence of an overt DIC, at least during a short time interval: in this condition heparin therapy seems therefore not advisable and even potentially dangerous.     

Hemostasis during the early stages of trauma: comparison with disseminated intravascular coagulation

Introduction

We tested two hypotheses that disseminated intravascular coagulation (DIC) and acute coagulopathy of trauma-shock (ACOTS) in the early phase of trauma are similar disease entities and that the DIC score on admission can be used to predict the prognosis of patients with coagulopathy of trauma.

Methods

We conducted a retrospective study of 562 trauma patients, including 338 patients whose data were obtained immediately after admission to the emergency department. We collected serial data for the platelet counts, global markers of coagulation and fibrinolysis, and antithrombin levels. DIC was diagnosed according to the Japanese Association for Acute Medicine (JAAM) DIC scoring system, and ACOTS was defined as a prothrombin-time ratio of >1.2.

Results

The higher levels of fibrin/fibrinogen degradation products (FDP) and D-dimer and greater FDP/D-dimer ratios in the DIC patients suggested DIC with the fibrinolytic phenotype. The DIC patients with the fibrinolytic phenotype exhibited persistently lower platelet counts and fibrinogen levels, increased prothrombin time ratios, higher FDP and D-dimer levels, and lower antithrombin levels compared with the non-DIC patients on arrival to the emergency department and during the early stage of trauma. Almost all ACOTS patients met the criteria for a diagnosis of DIC; therefore, the same changes were observed in the platelet counts, global markers of coagulation and fibrinolysis, and antithrombin levels as noted in the DIC patients. The JAAM DIC score obtained immediately after arrival to the emergency department was an independent predictor of massive transfusion and death due to trauma and correlated with the amount of blood transfused.

Conclusions

Patients who develop DIC with the fibrinolytic phenotype during the early stage of trauma exhibit consumption coagulopathy associated with increased fibrin(ogen)olysis and lower levels of antithrombin. The same is true in patients with ACOTS. The JAAM DIC score can be used to predict the prognosis of patients with coagulopathy of trauma.     

Kupffer cell-depleted rats have a diminished acute-phase response following major liver resection

Partial hepatectomy (PH)-induced Kupffer cell (KC) activation results in a rapid release of cytokines inducing the acute-phase response (APR). This study was done to evaluate the role of Kupffer cells (KCs) in the course of the APR following PH and a consecutive endotoxin challenge. KC depletion was performed in rats by i.v. administration of 1 mL liposome-encapsulated dichloromethylene diphosohonate (Cl2MDP). Control rats received 1 mL NaCl 0.9%. Forty-eight hours later, PH was performed. At 24 h after PH, rats were randomized to receive either 1 mL NaCl 0.9% (saline) or 50 microg/kg LPS i.v. in 1 mL. Animals were sacrificed at 4 h after LPS or saline infusion. The APR was determined by measuring hepatic gene expression of alpha 2-macroglobulin, alpha 1-acid glycoprotein, and IL-6 and expression of hepatic albumin. The APR was significantly depressed in KC-depleted rats. Despite increased IL-6 mRNA synthesis in response to low-dose LPS, no enhancement of acute-phase protein synthesis (APP) was found in KC-depleted rats. Hepatic failure was most profound in KC-depleted rats, as indicated by elevated plasma levels of liver transaminases and ammonia. We conclude that after PH, KC function in the remnant liver is important for the acute-phase reaction and reduces endotoxin-induced hepatocyte damage.     

阵发性睡眠性血红蛋白尿症患者血栓前状态的研究

目的：探讨阵发性睡眠性血红蛋白尿症（ＰＮＨ）患者易发生血栓形成的机制。方法：对２１例ＰＮＨ患者测定了１３项能反映血栓前状态的分子标志物或指标。结果：与正常对照比较，患者血浆纤维蛋白肽Ａ（ＦＰＡ）水平明显增高，抗凝血酶－Ⅲ（ＡＴ－Ⅲ）和蛋白Ｃ（ＰＣ）降低，血浆组织型纤溶酶原激活物（ｔ－ＰＡ）活性明显降低，ｔ－ＰＡ抑制物（ＰＡＩ）活性增高。血红蛋白尿急性发作期上述凝血与纤溶指标的变化较静止期更显著，合并血栓形成者变化的幅度最大。患者血小板相关指标无明显变化，血浆内皮素－１（ＥＴ－１）和ｖＷＦ∶Ａｇ水平正常。结论：ＰＮＨ患者存在血栓前状态，其发生可能主要与凝血机制亢进和纤溶机能减弱有关。     

Haemostatic disorders and respiratory distress in the newborn

Coagulation and fibrinolysis studies were performed on 64 newborns; 16 premature infants with hyaline membrane disease (HMD), 17 newborns with other forms of respiratory distress syndrome (RDS) (8 of them were premature), 31 healthy newborns (11 of them were premature). All the babies were studied once in the first 48 hours of life. There was no significant difference between sick and healthy babies for 5 parameters; platelet count, factor VIII, fibrinogen, fibrin(ogen) degradation products, euglobulin lysis time. Factor II, VII and X were low in all infants, and premature infants had significantly lower levels compared to full term newborns. Factor V, plasminogen, alpha 2 macroglobulin (alpha 2M) and antithrombin III (AT III) levels were significantly lower in sick infants. Except for AT III, these deficiencies were not related to prematurity. No significant difference was found between HMD and other RDS. Of the 33 sick infants, 5 developed laboratory findings consistent with disseminated intravascular coagulation (DIC). The results indicate that the coagulation and fibrinolytic abnormalities reported are not specific to HMD.     

Pharmacokinetics and systemic effects of tissue-type plasminogen activator in normal subjects

Pharmacokinetics and systemic effects of recombinant tissue-type plasminogen activator (rt-PA) were studied in 18 healthy male volunteers after 30-minute intravenous infusions of placebo, 0.25 mg/kg rt-PA, and 0.5 mg/kg rt-PA. Highly comparable pharmacokinetic parameters were obtained after analysis of rt-PA as both an antigen and an activity. Mean clearance (antigen) was 620 +/- 70 (SD) ml/min, volume of distribution at steady state was 8.1 +/- 0.8 L, initial volume of distribution was 4.4 +/- 0.6 L, and dominant half-life was 4.4 +/- 0.3 minutes. The pharmacokinetics of rt-PA were linear, showed low interindividual variation, and are compatible with rapid hepatic elimination of the protein. Systemic plasminogen activation was minimal as assessed by hemostatic assays of plasma samples treated with anti-rt-PA Immunoglobulin G (IgG) to inhibit in vitro fibrinogenolysis. Circulating fibrinogen levels, clotting times, and coagulation factors were unchanged; plasminogen and alpha 2-antiplasmin decreased maximally to 85% and 65% of baseline values, respectively. The data are consistent with the fibrin specificity of t-PA, which is derived from its role in physiologic fibrinolysis.     

Recombinant human soluble thrombomodulin improves mortality in patients with sepsis especially for severe coagulopathy: a retrospective study

Background

Disseminated intravascular coagulation (DIC) is associated with high mortality in patients with sepsis. Several studies reporting that recombinant human soluble thrombomodulin (rhTM) reduced mortality in sepsis patients. This retrospective cohort study aimed to evaluate the efficacy of rhTM for patients with mild coagulopathy compared with those with severe coagulopathy.

Methods

We evaluated about 90-day mortality and SOFA score. SOFA score was also evaluated for the following components: respiratory, cardiovascular, hepatic, renal and coagulation.

Results

All 69 patients were diagnosed with sepsis, fulfilled Japanese Association for Acute Medicine criteria for DIC, and were treated with rhTM. Patients were assigned to either the mild coagulopathy group (did not fulfill the International Society on Thrombosis and Haemostasis overt DIC criteria) or the severe coagulopathy group (fulfilled overt DIC criteria). The 90-day mortality was significant lower in severe coagulopathy group than mild coagulopathy group (P?=?0.029). Although the SOFA scores did not decrease in the mild coagulopathy group, SOFA scores decreased significantly in the severe coagulopathy group. Furthermore the respiratory component of the SOFA score significant decreased in severe coagulopathy group compared with mild coagulopathy group.

Conclusions

rhTM administration may reduce mortality by improving organ dysfunction especially for respiratory in septic patients with severe coagulopathy.

     

Tissue-type plasminogen activator increases the binding of glu-plasminogen to clots.

Porcine tissue-type plasminogen activator (t-PA) increases the binding of 125I-glu-plasminogen to clots made from human plasma or purified fibrinogen in a time and t-PA concentration dependent fashion. The accumulation of plasminogen was faster and greater on noncrosslinked plasma clots than on clots which had been crosslinked by Factor XIIIa. Furthermore, the uptake of plasminogen to crosslinked fibrin clots occurred at a slower rate in the presence of alpha 2-plasmin inhibitor (alpha 2 PI) than in its absence. The kinetics of the uptake of 125I-plasminogen were analyzed using SDS-polyacrylamide gel electrophoresis and radioautography of solubilized plasma clots formed in the presence of t-PA. During the initial phase there was a decrease of clot-bound glu-plasminogen; simultaneously, there was a slight increase in clot-bound glu-plasmin and in plasmin complexed to alpha 2 PI that was crosslinked to alpha-chain polymers of fibrin. This was followed by a marked increase in clot-bound plasminogen having glutamic acid as NH2-terminal (glu-plasminogen) and gluplasmin. t-PA-induced enhancement of glu-plasminogen uptake appears to be mediated by plasmin but does not require the conversion of glu-plasminogen to plasminogen having lysine or methionine as NH2-terminal. The described mechanism assures an adequate supply of clot-bound plasmin, which is the enzyme ultimately involved in the degradation of fibrin.     

Effects of two low-dose oral contraceptives on circulating components of the coagulation and fibrinolytic systems

We studied the effects on plasma levels of coagulation and fibrinolysis factors of two currently used "sub-50" oral contraceptive preparations (OCs), one containing 750 micrograms lynestrenol and 37.5 micrograms ethinyl estradiol (LYN-EE) and the other containing 150 micrograms levonorgestrel and 30 micrograms ethinyl estradiol (LNG-EE), in groups of about 25 women aged 21 +/- 2 years. After 3 months, plasminogen levels increased in the two experimental groups (LYN-EE and LNG-EE), by 40% and 32%, respectively. This change was positively correlated with changes in ceruloplasmin levels, indicating that an estrogenic effect might be involved. Histidine-rich glycoprotein concentration decreased by 26% and 16%, respectively. Tissue-type plasminogen activator (t-PA) activity increased by 260% and 167%; t-PA antigen decreased by 12% and 18%, and t-PA inhibitor activity decreased by 31% and 32%, respectively. In the coagulation system, in both groups factor XII increased by 47% and 34%, respectively. The main inhibitor of factor XII, C1-inactivator, decreased slightly, but this was significant only in the LNG-EE group. The von Willebrand factor antigen fell by 8% and 9%, whereas factor VIII activity did not change. Antithrombin III antigen decreased by 14% in both groups. Factor IX activity increased by 15% and 21%. The difference in hormonal effects of both preparations was reflected by the increases in sex hormone binding globulin (by 130% and 21%) and ceruloplasmin (by 98% and 51%), indicating that LYN-EE had a more estrogenic potency than LNG-EE. In a control group of 25 matched subjects, who were observed simultaneously, we found no significant changes.(ABSTRACT TRUNCATED AT 250 WORDS)     

The behavior of alpha2-plasmin inhibitor in fibrinolytic states.

Human plasma alpha2-plasmin inhibitor in fibrinolytic states was studied using immunochemical methods and radioiodinated plasminogen. The concentration and activity of plasma alpha2-plasmin inhibitor decreased when urokinase was added to plasma in vitro or infused intravenously in man. The decrease was associated with the appearance of plasmin-alpha2-plasmin inhibitor complex which subsequently disappeared from the circulation in a short time. A decrease of other major inhibitors, such as alpha2-macroglobulin and alpha1-antitrypsin, was not observed when the amount of urokinase added or infused was relatively small, and conversion of plasminogen to plasmin was not extensive. The formation of plasmin-alpha2-macroglobulin complex was observed only when plasma plasminogen was activated with a larger amount of urokinase, and after most of the alpha2-plasmin inhibitor was consumed by forming complexes with plasmin. The formation of plasmin-alpha1-antitrypsin complex was not observed even in the highly activated plasma unless exogenous plasmin was added to the plasma. alpha2-Plasmin inhibitor was the only inhibitor of which the concentration in plasma was significantly decreased in patients with disseminated intravascular coagulation and fibrinolysis among the major plasmin inhibitors in plasma. The most reactive inhibitor for regulating plasma fibrinolysis very likely is alpha2-plasmin inhibitor.     

Metformin prevents endotoxin-induced liver injury after partial hepatectomy

Metformin [2-(N,N-dimethylcarbamimidoyl)guanidine] is a drug used in the treatment of type 2 diabetes. Recent studies have suggested that metformin may have effects in addition to lowering serum glucose concentrations (e.g., anti-inflammatory). The aim of the present study was to determine whether metformin prevents the inflammatory reaction and liver damage in a model of postsurgical sepsis. Accordingly, rats underwent 2/3 partial hepatectomy (PH; or sham surgery); 48 h after surgery, animals were administered endotoxin (LPS; 1.5 mg/kg i.v.). Both PH and LPS alone caused some minor liver damage. However, their combined effect (PH/LPS) was synergistic, leading to robust hepatic damage, as indicated by plasma enzymes and histological assessment. Although metformin treatment did not alter changes caused by PH alone, it almost completely blunted the effects of LPS in the PH/LPS group. Increases in biomarkers of inflammation (e.g., interleukin 6, interferon gamma, and neutrophil number) were also blunted by metformin treatment. Furthermore, PH/LPS caused a >200x increase in hepatic plasminogen activator inhibitor 1 (PAI-1) mRNA expression and plasma PAI-1 protein. These increases were associated with inhibition of hepatic urokinase plasminogen activator activity and an increase in fibrin deposition, indicative of local thrombosis. These effects were markedly reduced by metformin treatment. In conclusion, these data demonstrate that metformin prevents liver damage in a model of postsurgical sepsis in rats by decreasing proinflammatory and hemostatic responses.     

Alpha 2-antiplasmin supplementation inhibits tissue plasminogen activator-induced fibrinogenolysis and bleeding with little effect on thrombolysis.

Tissue plasminogen activator (t-PA) causes fibrinogen proteolysis when alpha 2-antiplasmin levels fall, and this may contribute to t-PA-induced hemorrhage. Because clot-bound plasmin is protected from alpha 2-antiplasmin inhibition, we tested the possibility that alpha 2-antiplasmin supplementation would block t-PA-induced fibrinogenolysis and bleeding without affecting thrombolysis. When added to human or rabbit plasma, alpha 2-antiplasmin inhibits t-PA-induced fibrinogenolysis, but hat little effect on the lysis of 125I-fibrin clots. To examine its effect in vivo, rabbits with preformed 125I-labeled-jugular vein thrombi were randomized to receive t-PA, t-PA and alpha 2-antiplasmin, or saline. alpha 2-Antiplasmin infusion produced a modest decrease in t-PA-induced thrombolysis (from 40.2% to 30.1%, P = 0.12), but reduced fibrinogen consumption from 87% to 27% (P = 0.0001), and decreased blood loss from standardized ear incisions from 5,594 to 656 microliter (P < 0.0001). We hypothesize that alpha 2-antiplasmin limits t-PA-induced hemorrhage by inhibiting fibrinogenolysis and subsequent fragment X formation because (a) SDS-PAGE and immunoblot analysis indicate less fragment X formation in alpha 2-antiplasmin treated animals, and (b) when added to a solution of fibrinogen and plasminogen clotted with thrombin in the presence of t-PA, fragment X shortens the lysis time in a concentration-dependent fashion. These findings suggest that fragment X incorporation into hemostatic plugs contributes to t-PA-induced bleeding. By blocking t-PA-mediated fibrinogenolysis, alpha 2-antiplasmin supplementation may improve the safety of fibrin-specific plasminogen activators.     

Le système fibrinolytique : activation et inhibition. Ses modifications en cas de CIVD

The blood fibrinolytic system comprises an inactive proenzyme, plasminogen, that can be converted to the active enzyme, plasmin. Plasmin degrades fibrin and participates in the extracellular matrix remodelling. This conversion implies two physiological plasminogen activators (PA), the tissue type (t-PA) and the urinary type (u-PA). t-PA mediated plasminogen activation is mainly involved in the dissolution of fibrin in the circulation. u-PA binds to a specific cellular receptor (u-PAR), resulting in enhanced activation of cell bound plasminogen. Inhibition of the fibrinolytic system may occur by specific plasminogen activator inhibitors (PAI), or at the level of plasmin, mainly by α₂-antiplasmin. Recently a thrombin activatable fibrinolysis inhibitor (TAFI) has been described. By eliminating carboxyterminal lysine residues from partially degraded fibrin, it could participate to the control of in vivo fibrinolysis. During DIC, fibrinolysis is induced and septic DIC is characterized by a sustained increase in PAI-1 synthesis due to the presence of proinflammatory cytokines, mainly TNFα.     

急性心肌梗死患者脂蛋白(a)和凝血纤溶活性的关系以及尿激酶溶栓治疗对其影响

观察急性心肌梗死患者脂蛋白的（ａ）「ＬＰ（ａ）」与凝血和纤溶功能的关系以及尿激酶溶栓治疗对其影响。方法采用酶联免疫吸附双抗体夹心法检测２０例ＡＭＩ、３０例稳定型心绞痛、８例不稳定型心绞痛患者和２０例健康人以及ＡＭＩ溶栓后的血清ＬＰ（ａ）、血浆Ｄ－二聚体（ＤＤ）纤维蛋白单体（ＦＭ）和组织型纤溶酶原激活剂浓度。结果ＡＭＩ、ＵＡＰ和ＳＡＰ患者的ＬＰ（ａ）、ＤＤ和ＦＭ较对照组明显增高,而ｔ－ＰＡ明显降低（