Peritoneal lavage with activated protein C alters compartmentalized coagulation and fibrinolysis and improves survival in polymicrobial peritonitis

OBJECTIVE: During peritonitis, intra-abdominal fibrin entraps bacteria and hampers their elimination. Systemic administration of anticoagulant activated protein C improves survival in patients with severe sepsis, but its precise mode of action is unclear. This study in polymicrobial peritonitis assessed the effects of local activated protein C administration in peritoneal lavage fluid on coagulation, fibrinolysis, and survival. DESIGN: Prospective, randomized study. SETTING: University-based research laboratory. SUBJECTS: C57BL/6 mice. INTERVENTIONS: Twenty-four hours after induction of peritonitis by cecal ligation and puncture, mice underwent peritoneal lavage with activated protein C (1.0 microg/mL) or saline. Peritoneal lavage fluid, blood, and lungs were sampled after 24, 48, or 72 hrs (n = 8/group/time point). For survival analysis, maximum observation was 96 hrs (n = 22/group). Clotting time, tissue factor expression, thrombin-antithrombin complexes, fibrin degradation products (D-dimers), plasminogen activator, and plasminogen activator inhibitor were used to assess coagulation and fibrinolysis responses. MEASUREMENTS AND MAIN RESULTS: Activated protein C lavage reduced abdominal bacterial load, abdominal and pulmonary clotting times, D-dimers (p < .05 vs. saline), pulmonary tissue factor expression, and fibrin depositions, without clear effects on systemic thrombin generation. Activated protein C lavage decreased plasma and abdominal tissue plasminogen activator levels with increased inhibitor plasminogen activator inhibitor-1 levels (p < .05) but had reverse effects on pulmonary fibrinolysis. Survival improved from 55% (saline) to 80% after intra-abdominal activated protein C administration (p = .03). CONCLUSIONS: Peritoneal lavage with activated protein C may rebalance coagulation and fibrinolysis within compartments and improve survival in polymicrobial peritonitis.     

Anticoagulant and anti-inflammatory effects after peritoneal lavage with antithrombin in experimental polymicrobial peritonitis

BACKGROUND: In sepsis, coagulation inhibition using high-dose systemic antithrombin (AT) tends to improve survival. However, systemic AT use is complicated by increased risk of bleeding (odds ratio 1,7) and clinically important survival increase is seen only in the non-heparinized subgroup. Local (intra-abdominal) inhibition of coagulation with AT may be more effective. OBJECTIVES: To investigate effects of intra-abdominal high-dose recombinant human AT (rhAT) lavage on coagulation and inflammation in experimental polymicrobial sepsis. METHODS: Murine cecal ligation and puncture model was used with peritoneal lavage after 24 h, containing rhAT (3 IU mL-1) or saline. Clotting time, thrombin-antithrombin complexes (TAT), D-dimers, tissue-type plasminogen activator and plasminogen activator inhibitor-1 assessed coagulation and fibrinolysis responses. Inflammation was assessed by keratinocyte-derived chemokine (KC), interleukin-1beta (IL-1beta), IL-6, tumor necrosis factor-alpha (TNF-alpha), leukocyte count, myeloperoxidase and bacterial load. RESULTS: rhAT lavage prolonged abdominal clotting times and reduced D-dimers and TAT levels, indicating inhibited abdominal coagulation. Pulmonary clotting time and D-dimers decreased towards normal by rhAT lavage. Abdominal fibrinolysis was reduced after rhAT lavage, as were abdominal IL-1beta, KC, leukocytes and bacterial load. Pulmonary TNF-alpha, KC, myeloperoxidase and histopathological injury were decreased. Survival improved from 62% (saline lavage) to 83% (rhAT lavage, P<0.05). CONCLUSIONS: High-dose rhAT lavage inhibited coagulation activation, and reduced inflammatory responses in both abdominal and pulmonary compartments, ultimately improving survival.     

Nebulized anticoagulants limit coagulopathy but not inflammation in pseudomonas aeruginosa-induced pneumonia in rats

Disturbed alveolar fibrin turnover is a characteristic feature of pneumonia. Inhibitors of coagulation could exert lung-protective effects via anticoagulant (inhibiting fibrin deposition) and possibly anti-inflammatory pathways, but could also affect host defense. In this randomized controlled in vivo laboratory study, rats were challenged intratracheally with Pseudomonas aeruginosa, inducing pneumonia, and randomized to local treatment with normal saline (placebo), recombinant human activated protein C (rh-APC), plasma-derived antithrombin (AT), heparin, or danaparoid. Induction of P. aeruginosa pneumonia resulted in activation of pulmonary coagulation and inhibition of pulmonary fibrinolysis, as reflected by increased pulmonary levels of thrombin-AT complexes and fibrin degradation products and decreased pulmonary levels plasminogen activator activity. Pseudomonas aeruginosa pneumonia was accompanied by systemic coagulopathy, since systemic levels of thrombin-AT complexes increased, and systemic levels of plasminogen activator activity decreased. Although rh-APC and plasma-derived AT potently limited pulmonary coagulopathy, neither heparin nor danaparoid affected net pulmonary fibrin turnover. Recombinant human APC also displayed systemic anticoagulant effects. Neither bacterial clearance nor pulmonary inflammation was affected by anticoagulant therapy. Nebulization of rh-APC or plasma-derived AT attenuated pulmonary coagulopathy, but not bacterial clearance or inflammation, in a rat model of P. aeruginosa pneumonia.     

Local abnormalities in coagulation and fibrinolytic pathways predispose to alveolar fibrin deposition in the adult respiratory distress syndrome.

To determine the possible mechanism(s) promoting alveolar fibrin deposition in the adult respiratory distress syndrome (ARDS), we investigated the initiation and regulation of both fibrinolysis and coagulation from patients with ARDS (n = 14), at risk for ARDS (n = 5), and with interstitial lung diseases (ILD) (n = 8), and normal healthy individuals (n = 13). Bronchoalveolar lavage (BAL) extrinsic pathway inhibitor activity was increased in ARDS BAL compared with patients at risk for ARDS (P = 0.0146) or normal controls (P = 0.0013) but tissue factor-factor VII procoagulant activity was significantly increased in ARDS BAL compared with all other groups (P less than 0.001). Fibrinolytic activity was not detectable in BAL of 10 of the 14 patients with ARDS and low levels of activity were found in BAL of the other four ARDS patients. Depressed fibrinolysis in ARDS BAL was not due to local insufficiency of plasminogen; rather, there was inhibition of both plasmin and plasminogen activator. Plasminogen activator inhibitor 1 was variably detected and low levels of plasminogen activator inhibitor 2 were found in two ARDS BAL samples, but plasminogen activator inhibitor 2 was otherwise undetectable. ARDS BAL antiplasmin activity was, in part, due to alpha 2-antiplasmin. We conclude that abnormalities that result in enhanced coagulation and depressed fibrinolysis, thereby predisposing to alveolar fibrin deposition, occur in the alveolar lining fluids from patients with ARDS.     

Pulmonary coagulopathy as a new target in therapeutic studies of acute lung injury or pneumonia--a review

OBJECTIVES: To review the involvement of coagulation and fibrinolysis in the pathogenesis of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), pulmonary infection, and ventilator-induced lung injury (VILI). DATA SOURCE: Published articles on experimental and clinical studies of coagulation and fibrinolysis in ALI/ARDS, pneumonia, and mechanical ventilation. CONCLUSIONS: Alveolar fibrin deposition is an important feature of ALI/ARDS and pulmonary infection. The mechanisms that contribute to disturbed alveolar fibrin turnover are localized tissue factor-mediated thrombin generation and depression of bronchoalveolar urokinase plasminogen activator-mediated fibrinolysis, caused by the increase of plasminogen activator inhibitors. These effects on pulmonary coagulation and fibrinolysis are regulated by various proinflammatory cytokines and are similar to those found in the intravascular spaces during severe systemic inflammation. Some studies also suggest that pulmonary coagulopathy is a feature of VILI. Recent studies have demonstrated the beneficial effect of anticoagulant therapy in sepsis. Theoretical considerations suggest that this anticoagulant therapy will benefit patients with primary lung pathology including VILI, but clinical studies are needed to examine this hypothesis before such therapy is to be advocated as a standard of care in critically ill patients.     

Plasma‐derived human antithrombin attenuates ventilator‐induced coagulopathy but not inflammation in a Streptococcus pneumoniae pneumonia model in rats

Summary. Background: Mechanical ventilation exaggerates pneumonia‐associated pulmonary coagulopathy and inflammation. We hypothesized that the administration of plasma‐derived human antithrombin (AT), one of the natural inhibitors of coagulation, prevents ventilator‐induced pulmonary coagulopathy, inflammation and bacterial outgrowth in a Streptococcus pneumoniae pneumonia model in rats. Methods: Forty‐eight hours after induction of S. pneumoniae pneumonia rats were subjected to mechanical ventilation (tidal volume 12 mL kg^?1, positive end‐expiratory pressure 0 cmH₂O and inspired oxygen fraction 40%). Rats were randomized to systemic treatment with AT (250 IU administered intravenously (i.v.) before the start of mechanical ventilation) or placebo (saline). Non‐ventilated, non‐infected rats and non‐ventilated rats with pneumonia served as controls. The primary endpoints were pulmonary coagulation and inflammation in bronchoalveolar lavage fluid (BALF). Results: Pneumonia was characterized by local activation of coagulation and inhibition of fibrinolysis, resulting in increased levels of fibrin degradation products and fibrin deposition in the lung. Mechanical ventilation exaggerated pulmonary coagulopathy and inflammation. Systemic administration of AT led to supra‐normal BALF levels of AT and decreased ventilator‐associated activation of coagulation. AT neither affected pulmonary inflammation nor bacterial outgrowth from the lungs or blood.Conclusions: Plasma‐derived human AT attenuates ventilator‐induced coagulopathy, but not inflammation and bacterial outgrowth in a S. pneumoniae pneumonia model in rats.     

Blood coagulation and fibrinolysis during normal pregnancy

Fifty-six pregnant women (gestational age 6-40 weeks) were evaluated for their coagulation activation (fibrin monomers and thrombin-antithrombin III complex) and for their fibrinolysis profile by determining tissue plasminogen activator, plasminogen activator inhibitor, plasminogen, alpha 2-antiplasmin and D-dimer. Fibrin monomers and thrombin-antithrombin III complexes were found to be significantly increasing with gestational age. All the fibrinolytic parameters showed a steady growth with the progress of the pregnancy, with the exception of tissue plasminogen activator which showed a significant decrease with gestational age, but mainly within the reference range. These results suggest a stimulation of the coagulation system and an activation of fibrinolysis with ongoing pregnancy, although the increasing alpha 2-antiplasmin and plasminogen levels and the decreasing tissue plasminogen activator concentrations do not conform to this trend.     

Plasma concentration of coagulation and fibrinolysis factors and platelet function in hypertension

Fifty-one patients with mild hypertension were evaluated in relation to the plasma concentrations of coagulation and fibrinolysis factors as well as for the aggregability of their platelets. In a considerable number of the patients (18/51), a significantly enhanced in vitro ADP (2 mumol/l)-induced aggregation was found. In the coagulation line significant increases could be demonstrated in fibrinogen, fibrin monomers and thrombin-antithrombin III. The fibrinolysis system showed significant increases for D-dimers, tissue plasminogen activator antigen and plasminogen activator inhibitor, whereas the tissue plasminogen activator activity was significantly diminished. Remarkably, there seems to be a discrepancy between the (low) tissue plasminogen activator activity and the (higher) plasminogen activator antigen concentration. Alterations in the plasma concentrations of the investigated coagulation and fibrinolysis factors and in the aggregability of the platelets are indicative of an involvement of coagulation, fibrinolysis and platelets in hypertension, which can be considered as partial risk factors for thrombophilia.     

Bronchoalveolar hemostasis in lung injury and acute respiratory distress syndrome

Summary. Enhanced intrapulmonary fibrin deposition as a result of abnormal broncho‐alveolar fibrin turnover is a hallmark of acute respiratory distress syndrome (ARDS), pneumonia and ventilator‐induced lung injury (VILI), and is important to the pathogenesis of these conditions. The mechanisms that contribute to alveolar coagulopathy are localized tissue factor‐mediated thrombin generation, impaired activity of natural coagulation inhibitors and depression of bronchoalveolar urokinase plasminogen activator‐mediated fibrinolysis, caused by the increase of plasminogen activator inhibitors. There is an intense and bidirectional interaction between coagulation and inflammatory pathways in the bronchoalveolar compartment. Systemic or local administration of anticoagulant agents (including activated protein C, antithrombin and heparin) and profibrinolytic agents (such as plasminogen activators) attenuate pulmonary coagulopathy. Several preclinical studies show additional anti‐inflammatory effects of these therapies in ARDS and pneumonia.     

Transgenic tissue-type plasminogen activator expression improves host defense during Klebsiella pneumonia

Summary.  Background:  Severe pneumonia is associated with a local inhibition of fibrinolysis in the lung as reflected by strongly reduced pulmonary plasminogen activator activity. Objectives:  To study the effect of elevation of local plasminogen activator activity during pneumonia caused by the common respiratory pathogen Klebsiella pneumoniae . Methods:  Female C56Bl/6 mice were inoculated intranasally with a replication-defective adenoviral vector expressing human tissue-type plasminogen activator or a control vector 24 h before intranasal infection with K. pneumoniae. Results:  Mice infected with Klebsiella via the airways developed overt pneumonia, which was accompanied by a downregulation of pulmonary tissue-type plasminogen activator levels at protein and mRNA levels. Pulmonary overexpression of human tissue-type plasminogen activator resulted in increased fibrinolytic activity in the lungs during pneumonia, as indicated by higher D-dimer levels and reduced fibrin deposition. Interestingly, overexpression of tissue-type plasminogen activator markedly improved host defense against pneumonia: mice treated with the tissue-type plasminogen activator vector displayed less bacterial growth and dissemination, attenuated distant organ injury and a reduced mortality. Conclusions:  These data demonstrate that local elevation of plasminogen activator activity in the lungs improves host defense against severe gram-negative pneumonia and sepsis.     

Activation of the fibrinolytic system and utilization of the coagulation inhibitors in sepsis: comparison with severe sepsis and septic shock

OBJECTIVES: To determine whether the fibrinolytic system is activated and coagulation inhibitors are utilized in sepsis, to compare the findings detected in sepsis with those found in severe sepsis and septic shock, and to compare the role played by different infectious pathogens on fibrinolysis and coagulation inhibitors. DESIGN AND SETTING: Prospective study comparing patients with sepsis, severe sepsis, and septic shock and healthy volunteers in the general intensive care unit of a tertiary university hospital. PATIENTS: Eighty-two consecutive septic patients (47 with sepsis, 18 with severe sepsis, and 17 with septic shock), and 14 healthy volunteers (controls). MEASUREMENTS AND RESULTS: After blood sampling we measured activation markers of fibrinolysis [plasmin/alpha(2)-antiplasmin complexes (PAP), complexes of tissue plasminogen activator/plasminogen activator inhibitor (tPA/PAI), fibrin(ogen) degradation products (FDPs), D-dimmers fibrin degradation products (D-d)], the utilization marker of antithrombin III (ATIII) thrombin/antithrombin complexes (TAT), several factors of fibrinolysis [plasminogen, tissue plasminogen activator (tPA), plasminogen activator inhibitor 1 (PAI-1), alpha(2)-antiplasmin], and the natural coagulation inhibitors [ATIII, protein C (PrC), protein S (PrS)]. In sepsis, PAP, FDPs, D-d, and TAT were increased to 439.8+/-32.35 microg/l, 57% positive, 49% positive, and 3.46+/-0.27 microg/l, respectively, compared with control subjects (205.57+/-28.58 microg/l, 0% positive, 7% positive, and 1.61+/-0.1 microg/l, respectively). These markers further increased in severe sepsis and septic shock. With the exception of a decrease in ATIII and an increase in tPA and PAI-1, coagulation inhibitors and factors of fibrinolysis were not changed in sepsis. In severe sepsis and mainly in septic shock, coagulation inhibitors (ATIII, PrC) and plasminogen were markedly decreased, whereas tPA and PAI-1 were further increased. All changes were independent of the causative infectious pathogen. CONCLUSIONS: Fibrinolysis is strongly activated and ATIII is utilized in sepsis. These findings are further enhanced in severe sepsis and septic shock. In sepsis only ATIII is decreased. In contrast, in severe sepsis and mainly in septic shock plasminogen and the main coagulation inhibitors (i.e., ATIII, PrC) are depleted, indicating exhaustion of fibrinolysis and coagulation inhibitors. Finally, Gram-positive, Gram-negative and other micro-organisms produce identical impairment.     

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.     

Evaluation of the fibrinolytic system in full-term neonates

Summary Plasminogen activity and antigen, euglobulin fibrinolytic activity, tissue-type plasminogen activator activity and antigen urokinase-type plasminogen activator antigen, plasminogen activator inhibitor-1 activity and antigen, plasminogen activator inhibitor-2 antigen, tissue-type plasminogen activator/plasminogen activator inhibitor complexes, α₂-antiplasmin, histidine-rich glycoprotein, and fibrinogen/fibrin degradation products were measured in blood samples taken from the umbilical vein of 100 healthy full-term newborns. Results were compared with a control group of 30 healthy adults. The overall fibrinolytic activity assessed on fibrin plates was significantly increased (P<0.002). We also observed high tissue-type plasminogen activator activity levels (P<0.001), whereas urokinase-type plasminogen activator antigen levels were lower than in adults. There was a significant reduction in plasminogen activity and antigen (P<0.0001), plasminogen activator inhibitor-1 activity (P<0.05), α₂-antiplasmin (P<0.0001), and histidine-rich glycoprotein (P<0.0001), whereas plasminogen activator inhibitor-2, tissue-type plasminogen activator/plasminogen activator inhibitor complexes and fibrinogen/fibrin degradation products did not differ between groups. We conclude that in the newborn there is increased fibrinolytic activity, mainly due to increased plasminogen activators and reduced fibrinolysis inhibition, without systemic fibrinolysis and fibrinogenolysis.     

Hemostatic markers in surgery: a different fibrinolyfic activity may be of pathophysiological significance in orthopedic versus abdominal surgery

Without prophylaxis, patients subjected to major abdominal surgery have a risk of deep vein thrombosis of approximately 30%, while the rate varies between 40% and 60% in orthopedic surgery. The reasons for this discrepancy are not completely understood. The present study was designed to compare the pre- and postoperative behavior of different coagulation and fibrinolysis parameters in patients undergoing both types of surgery, receiving low molecular weight heparin prophylaxis. Samples were taken before operation and on postoperative days 1,3, and 7. The following parameters were assessed: prothrombin fragment 1+2, thrombin-antithrombin III complexes, fibrinopeptide A, tissue plasminogen activator, plasminogen activator inhibitor, plasmin-α₂-antiplasmin complexes, and fibrin degradation products. We found a significant increase in the clotting markers postoperatively compared with preoperative values (P<0.05), both in abdominal and orthopedic surgery, indicating a marked hemostatic activation which remained until postoperative day 7. A significant increase in plasminogen activator inhibitor (P<0.01) and a decrease in tissue plasminogen activator and plasmin-α₂-antiplasmin complexes was also observed early after operation. The plasminogen activator inhibitor activity decreased, while tissue plasminogen activator and plasmin-α₂-antiplasmin levels increased significantly on days 3 and 7 (P<0.05). Fibrin degradation products significantly increased throughout the postoperative period (P<0.01). Preoperatively, we found higher plasminogen activator inhibitor activity and lower tissue plasminogen activator and plasmin-α₂-antiplasmin complexes (P<0.05) in patients undergoing hip replacement compared with abdominal surgery. Fibrin degradation products were also significantly lower on postoperative day 3 in patients undergoing hip replacement (P<0.01). We suggest that the lower preoperative fibrinolytic activation observed in patients undergoing orthopedic surgery compared with abdominal surgery might have pathophysiological consequences. Our results also indicate that the hemostatic activation persists beyond the 7th postoperative day despite prophylaxis.     

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。     

The regulation by fibrinogen and fibrin of tissue plasminogen activator kinetics and inhibition by plasminogen activator inhibitor 1

BACKGROUND: Tissue plasminogen activator (tPA) is unusual in the coagulation and fibrinolysis cascades in that it is produced as an active single-chain enzyme (sctPA) rather than a zymogen. Two chain tPA (tctPA) is produced by plasmin but there are conflicting reports in the literature on the behaviour of sc- and tctPA and little work on inhibition by the specific inhibitor plasminogen activator inhibitor-1 (PAI-1) under physiological conditions. OBJECTIVES: To perform a systematic study on the kinetics of sctPA and tctPA as plasminogen activators and targets for PAI-1. METHODS: Detailed kinetic studies were performed in solution and in the presence of template stimulators, fibrinogen and fibrin, including native fibrin and partially digested fibrin. Numerical simulation techniques were utilized to cope with the challenges of investigating kinetics of activation and inhibition in the presence of fibrin(ogen). RESULTS: Enzyme efficiency (k(cat)/K(m)) was higher for tctPA than sctPA in solution with chromogenic substrate (3-fold) and plasminogen (7-fold) but in the presence of templates, such as fibrinogen and native or cleaved fibrin, the difference disappeared. sctPA was more susceptible to PAI-1 in buffer solution and in the presence of fibrinogen; however, in the presence of fibrin, PAI-1 inhibited more slowly and there was no difference between sc and tctPA. CONCLUSIONS: Fibrinogen and fibrin modulate the activity of tPA differently in regard to their activation of plasminogen and inhibition by PAI-1. Fibrinogen and fibrin stimulate tPA activity against plasminogen but fibrin protects tPA from PAI-1 to promote fibrinolysis.     

Aerosolized tissue plasminogen inhibitor improves pulmonary function in sheep with burn and smoke inhalation

Acute respiratory distress syndrome is a major complication in patients with thermal injury. The obstruction of the airway by cast material, composed in part of fibrin, contributes to deterioration of pulmonary gas exchange. We tested the effect of aerosol administration of tissue plasminogen activator, which lyses fibrin clots, on acute lung injury in sheep that had undergone combined burn/smoke inhalation injury. Anesthetized sheep were given a 40% total body surface, third degree burn and were insufflated with cotton smoke. Tissue plasminogen activator (TPA) was nebulized every 4 h at 1 or 2 mg for each nebulization, beginning 4 h after injury. Injured but untreated control sheep developed multiple symptoms of acute respiratory distress syndrome: decreased pulmonary gas exchange, increased pulmonary edema, and extensive airway obstruction. These control animals also showed increased pulmonary transvascular fluid flux and increased airway pressures. These variables were all stable in sham animals. Nebulization of saline or 1 mg of TPA only slightly improved measures of pulmonary function. Treatment of injured sheep with 2 mg of TPA attenuated all the pulmonary abnormalities noted above. The results provide evidence that clearance of airway obstructive cast material is crucial in managing acute respiratory distress syndrome resulting from combined burn and smoke inhalation injury.     

Specific coagulation and fibrinolysis tests as biochemical markers in traumatic-induced adult respiratory distress syndrome

There is a great demand for more specific methods for assaying individual components of coagulation and fibrinolysis, with the chief aim being to use them as biochemical markers of the Adult Respiratory Distress Syndrome (ARDS) induced by severe trauma. This prospective study was undertaken on 18 severely traumatized patients in various stages of shock admitted to the Intensive Care Unit of the University Hospital in Uppsala, Sweden. After haemodynamic restitution, during which surgery was often required as an intervening procedure, the patients were carefully studied regarding pulmonary function, coagulation and fibrinolysis. Eight patients developed ARDS according to our criteria, and one patient died from this condition. It was found that patients who developed ARDS had significantly lower levels of antithrombin-III, higher levels of von Willebrand factor levels, higher levels of tissue plasminogen activator inhibitors and lower levels of plasminogen as compared with those who did not develop this condition. We believe that these coagulation and fibrinolysis variables can be used along with appropriate pulmonary function tests as specific biochemical markers to disclose the development of traumatic-induced ARDS.     

Upregulation of fibrinolysis by adenovirus-mediated transfer of urokinase-type plasminogen activator genes to lung cells in vitro and in vivo

Impaired fibrinolytic activity within the lungs is a common manifestation of acute and chronic inflammatory lung diseases. Our previous work using transgenic mice showed that upregulation of fibrinolysis reduced pulmonary fibrosis following bleomycin-induced inflammatory lung injury. As a strategy to accelerate fibrinolysis, we generated recombinant adenoviruses containing human and mouse urokinase-type plasminogen activator (uPA) cDNAs. Both vectors induced the expression of functional uPA in human lung-derived epithelial A549 cells. A single intratracheal instillation of these uPA-containing adenoviruses into mouse lungs resulted in increased plasminogen activator activity in bronchoalveolar lavage fluid for at least 2 weeks. Plasma-derived fibrin-rich matrices overlaid on A549 cells infected with these uPA vectors were lysed efficiently in a dose-dependent fashion. Similarly, fibrin matrices formed within intact lungs that had been infected with these uPA-containing adenoviruses were also lysed more rapidly compared with noninfected and control virus-infected lungs. These results indicate that adenovirus-mediated transduction of uPA successfully upregulates fibrinolysis in vitro and in vivo. These uPA vectors can be readily used for testing the role of the fibrinolytic system in animal models of lung fibrosis, with particular attention to their therapeutic potential.     

The extent of diffuse intravascular coagulation and fibrinolysis in patients with liver cirrhosis.

Twenty-five patients with different stages of liver cirrhosis were evaluated with regard to the degree of liver synthesis reduction, the extent of the decrease of blood coagulation factors and/or alterations of the fibrinolytic system. For the assessment of the residual level of liver synthesis we used pseudo-cholinesterase and serum albumin as references. We did not find a correlation between these quantities and antithrombin III or fibrinogen, but highly significant inverse correlations with tissue plasminogen activator activity and D-dimer concentration. We found considerable alterations in the concentrations of the coagulation and fibrinolysis factors, with the exception of fibrinogen and plasminogen activator inhibitor. Significant increases were seen for thrombin-antithrombin III complex, tissue plasminogen activator activity and D-dimer, while significant decreases were seen for antithrombin III and alpha 2-antiplasmin, compared with a group of healthy volunteers. In the group of patients with liver cirrhosis and reduced liver synthesis, as documented by lowered pseudo-cholinesterase and serum albumin, the reduction of both antithrombin III and alpha 2-antiplasmin was most prominent. Intravascular coagulation was negligibly small. For the fibrinolytic system, the increase of tissue plasminogen activator, the decrease of the fibrinolysis inhibitor (alpha 2-antiplasmin) and the elevated D-dimer concentration seem to be important. These results suggest an acceleration of fibrinolysis and the prolonged presence of cross-linked fibrin degradation products.