Evidence of increased oxidative stress and a change in the plasminogen activator inhibitor (PAI)-1 to PAI-2 ratio in early-onset but not late-onset preeclampsia

OBJECTIVE

The aims of this study were to measure the degree of oxidative stress and alterations in plasminogen activator inhibitor (PAI) type 1 and PAI-2 ratio in women with early-onset and late-onset preeclampsia.

STUDY DESIGN

A case-control study was conducted in women with early-onset (24-32 weeks' gestation; n=18) and late-onset (35-42 weeks' gestation; n=20) preeclampsia and in control pregnant women at corresponding gestational weeks. Placenta, urine, and serum samples were collected.

RESULTS

In early-onset preeclampsia, the median placental concentration of 8-iso-prostaglandin (PG)-F2alpha was higher and the PAI-1 to PAI-2 ratio higher than in early controls. These values did not differ between women with late-onset preeclampsia and their corresponding controls. Serum concentrations of 8-iso-PGF2alpha and vitamins C and E did not differ between cases and controls.

CONCLUSION

Early-onset but not late-onset preeclampsia is associated with increased placental oxidative stress and increased PAI-1 to PAI-2 ratio.

Variations in fibrinolytic parameters and inhibin-A in pregnancy: related hypertensive disorders

BACKGROUND

The mechanisms leading to pregnancy-related hypertensive disorders, and pregnancy-induced hypertension (PIH) and pre-eclampsia (PE) in particular, are still not clear. Diagnostic criteria are clinical because specific markers of the condition are lacking. A role of the fibrinolytic system has been suggested.

OBJECTIVES

We aimed to evaluate the behavior of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor type 1 (PAI-1), PAI-2, and the placental hormone inhibin-A in women with a normal pregnancy vs. women with pregnancies complicated by PIH or PE.

METHODS

Blood samples were drawn between the 25th and 30th gestational week (GW) and between the 31st and 36th GW in order to assay t-PA, PAI-1, PAI-2 and inhibin-A; routine biochemical exams, ultrasonography umbilical artery pulsatility index (PI), placental weight and newborn weight were measured.

RESULTS

In pregnancies complicated by hypertensive disorders, PAI-1 levels were higher than in controls and increased significantly after the 25th GW, especially in PE, as did inhibin-A. PAI-2 levels were significantly lower after the 30th GW in patients with PIH and PE. The PAI-1/PAI-2 ratio was significantly higher in PE patients than in controls as of the 25th GW, but only after the 30th GW in patients with PIH. Inhibin-A was significantly correlated with fibrinolytic parameters, and inversely with newborn weight. Receiver-operator characteristic curves for PAI-1 and inhibin-A showed a high sensitivity and specificity for PE. PAI-2 correlated with newborn and placental weight, and inversely with PI of the umbilical artery.

CONCLUSIONS

Fibrinolytic tests (especially PAI-1) and inhibin-A monitoring during pregnancy may help in the early diagnosis of pregnancy-related hypertensive disorders.

The effect of levonorgestrel-releasing intrauterine system use on menstrual blood loss and the hemostatic, fibrinolytic/inhibitor systems in women with menorrhagia

BACKGROUND

Menorrhagia is known to be associated with uterine fibroids, adenomyosis, pelvic infections, endometrial polyps and clotting defects. A viable alternative therapy to hysterectomy should alleviate heavy menstrual blood flow and consequently improve the quality-of-life measures in women presenting with menorrhagia. The levonorgestrel-releasing intrauterine system (LNG-IUS) ranks higher than medical treatments in terms of efficacy, comparable improvements in quality of life and psychological well-being.

OBJECTIVE

The purpose of the study was to determine the effects of 6 months of LNG-IUS use on menstrual blood loss and the hemostatic, fibrinolytic/inhibitor systems in blood and the endometrium in women with menorrhagia with known pathologic causes.

PATIENTS AND METHODS

Samples from 41 women were analyzed. Hemoglobin, hematocrit, thrombelastography, tissue-type plasminogen activator (t-PA), urokinase plasminogen activator (u-PA), u-PA receptor (u-PAR), plasminogen activator inhibitor-1/2 (PAI-1/2), D-dimer and von Willebrand factor (VWF) were determined, and t-PA, u-PA and PAI-1/2 were also determined in endometrial tissue extracts.

RESULTS

Menorrhagia was reduced in 89% of women by 3 months; by 6 months all women had no menorrhagia, and 39% of women had become amenorrhoeic. Hemoglobin and hematocrit levels showed improvement, and reached normal reference levels by 6 months. There were no systemic changes in the fibrinolytic/inhibitor systems and VWF, except for a decreased u-PAR level. However, in the endometrium, significant elevations in PAI-1/2 together with u-PAR levels were seen at 6 months.

CONCLUSIONS

The slow levonorgestrel-release intrauterine device use results in high expression of fibrinolytic inhibitors (PAI-1/2) and upregulated u-PAR expression in the endometrium. Systemic hemostasis was not significantly altered. The study demonstrated that LNG-IUS is highly effective in the treatment of menorrhagia with known pathologic causes.

The relation between plasminogen activator inhibitor activity and disease activation in acute myeloblastic leukaemia patients

Coagulation and fibrinolytic abnormalities are common in patients with acute myeloblastic leukaemia (AML) like other forms of leukaemias. In this study, we investigated if total plasminogen activator inhibitor (PAI) activity, which is believed to increase in initial diagnosis and relapse in AML patients could be accepted as a relapse criterion or not. Total of 34 AML patients and 18 healthy volunteers were included in this study. The patients' diagnosis were based on clinical criteria as well as morphological, cytochemical, immunuphenotypic examinations of peripheral blood and bone marrow specimens. Total PAI activity was measured with Dade Behring Bericrom PAI reagent in BCS system. Total PAI activity was higher than 3.5 U/ml in 11 AML patients while it was normal (0.3-3.5 U/ml) in control group (P < 0.01). There was no significant difference in total PAI activity between AML subgroups (P > 0.05). We found significant difference in total PAI activity between patients who have active disease and remission. In conclusion, the total PAI activity could be accepted as a relapse and an initial diagnosis criterion of AML patients during follow up.

Concentrations of plasminogen activators and their inhibitors in blood preconceptionally, during and after pregnancy

BACKGROUND

Haemostasis is a complex balance of activating and inhibitory pathways resulting in coagulation and lysis. Normal pregnancy is associated with hypercoagulation that is even more profound in complicated pregnancies.

OBJECTIVE

To study the role of the plasminogen-activator system in complicated pregnancy with regard to haemostasis, it is essential to have reference values of components of this system during uneventful pregnancy. In this study we investigated the concentrations of six different components of the plasminogen-activator system preconceptionally, during and after uncomplicated pregnancies.

MATERIAL AND METHODS

Tissue-type and urokinase-type plasminogen activator (tPA and uPA), plasminogen inhibitor type-1 and -2 (PAI-1 and-2), and the complexes between tPA and PAI-1, and between uPA and PAI-1 (tPA-PAI-1, uPA-PAI-1) were measured by ELISAs in blood obtained preconceptionally, at 6, 10, 20, 32 weeks of gestation, and 6 weeks after delivery in uncomplicated pregnancies (n=41; all six parameters n=22).

RESULTS

tPA and uPA concentrations decreased in the first 10 weeks of pregnancy and subsequently increased in the third trimester. PAI-1 concentrations increased in the third trimester and PAI-2 concentrations increased throughout pregnancy (preconception versus 32 weeks of gestation; 38.73 versus 102.23ng/ml, and 0.024 versus 151.06ng/ml, respectively). tPA-PAI-1 and uPA-PAI-1 complex concentrations decreased in the first trimester, followed by an increase in the third trimester. The concentrations of all components returned to the preconception values 6 weeks after delivery.

CONCLUSION

This study provides longitudinal data on activating and inhibitory components of the plasminogen-activator system during pregnancy. Insight in the longitudinal changes in these concentrations may be of help in the understanding of the thrombotic tendency in pregnancy complications such as preeclampsia.

Increased immunohistochemical expression of thrombomodulin at placental perivascular myofibroblast in severe preeclampsia (PE)

The presence of pro-coagulant and anti-coagulant components of the placental vascular endothelium and syncytiotrophoblast are essential for homeostasis. Vascular endothelium prevents blood clot formation in vivo by involving a cell surface thrombin-binding glycoprotein, thrombomodulin (TM), that activates plasma anti-coagulant protein C. The TM levels increase during pregnancy, but the fibrinolytic capacity diminishes. Since vascular lesions with placental coagulation disorders can be associated with preeclampsia (PE), we hypothesized that TM expression in the stem villous vasculature and syncytiotrophoblast of the placenta are impaired in PE. Plasma and placental tissue samples were collected from PE (n=12) and normotensive pregnant patients (n=11). Patient's gestational age was 35.7+/-1.2 (normotensive) and 30.6+/-1.5 weeks (PE). Blood samples were drawn 30 min before delivery. Serum PAI-1 and PAI-2 antigens were determined by enzyme-linked immunoabsorbent assay (ELISA). A monoclonal antibody specific for TM was used for immunohistochemical tissue staining (ABC) and the staining was quantified by semi quantitative scores. Results show no intensity differences at the apical syncytiotrophoblast between the two groups. However, in preeclamptic placenta, TM expression diminished in the endothelium of the stem villi arteries and increased in the perivascular and stromal myofibroblats in cases of severe PE. TM changes were associated with an increased PAI-1/PAI-2 ratio. It is suggested that in severe PE, the decreased placental blood flow may be due to structural and functional impairment of the endothelium of the stem villi vessels and the surrounding perivascular and stromal myofibroblast, by increasing TM expression which may modulate fetal blow flow in the villous tree.

Haemostatic changes in pregnancy

In normal pregnancy, there is a marked increase in the procoagulant activity in maternal blood characterized by elevation of factors VII, X, VIII, fibrinogen and von Willebrand factor, which is maximal around term. This is associated with an increase in prothrombin fragments (PF1+2) and thrombin-antithrombin complexes. There is a decrease in physiological anticoagulants manifested by a significant reduction in protein S activity and by acquired activated protein C (APC) resistance. The overall fibrinolytic activity is impaired during pregnancy, but returns rapidly to normal following delivery. This is largely due to placental derived plasminogen activator inhibitor type 2 (PAI-2), which is present in substantial quantities during pregnancy. D-dimer, a specific marker of fibrinolysis resulting from breakdown of cross-linked fibrin polymer by plasmin, increases as pregnancy progresses. Overall, there is a 4- to 10-fold increased thrombotic risk throughout gestation and the postpartum period. Local haemostasis at the placental throphoblast level is characterized by increased tissue factor (TF) expression and low expression of the inhibitor TFPI. Microparticles derived from maternal endothelial cells and platelets, and from placental throphoblasts may contribute to the procoagulant effect. Local anticoagulant mechanisms on placental throphoblasts are important for counterbalance of the procoagulant milieu. Disruption of anticoagulant mechanisms, for example, autoantibodies, to annexin V may increase pregnancy complications in patients with antiphospholipid antibodies (APLA).

An ELISA avoiding interference by heterophilic antibodies in the measurement of components of the plasminogen activation system in blood

Endogenous heterophilic antibodies in blood are known to interfere with two-site enzyme-linked immunosorbent assays (ELISAs) evoking false positive signals. In the present study, we describe an assay for the assessment of components of the plasminogen activation system (uPA, tPA and PAI-1, and their complexes) in blood which is not susceptible to interference by heterophilic antibodies. In the ELISA format, two avian (duck, chicken) antibodies are employed in the pre-analyte and two mammalian (rabbit, goat) antibodies in the post-analyte stage. The assay is compared to our earlier reported ELISA for measuring uPA, tPA and PAI-1 components in tumor tissue extracts. Applying the so-called "nonsense formats", designed against non-existent components, to the NIBSC reference preparation of rheumatoid factor (RF), no response was found with the new assay, whereas a clear RF dose-dependent interfering signal was observed with the original assay designed for tumor tissue extracts. Analysis of tumor-tissue based international reference preparations (RBG EORTC 101094 and 040297), human anti-mouse antibodies (HAMA) containing sera, and sera from patients with rheumatoid arthritis (RA), also displayed no false positive signals. In conclusion, we have developed an ELISA that permits the determination of blood levels of components in the urokinase system, free from disturbance by endogenous heterophilic antibodies.

Levels of plasminogen activators and their inhibitors in maternal and umbilical cord plasma in severe preeclampsia

OBJECTIVE

The purpose of this study was to evaluate the plasminogen activator system in maternal and umbilical cord plasma in patients with severe preeclampsia compared with control subjects with normotensive pregnancies.

STUDY DESIGN

Maternal blood was sampled from 42 patients at a median gestational age of 32 weeks; after delivery, arterial and venous umbilical cord blood was sampled from 37 and 36 of these patients, respectively. Maternal blood from women with uncomplicated pregnancies was sampled at the gestational age of 32 weeks (n = 18, group I), and umbilical cord blood was sampled after premature deliveries of normotensive pregnancies (n = 5, group II). Data were analyzed with the use of Mann-Whitney U tests.

RESULTS

Patients had significantly higher tissue plasminogen activator (P <.01) and unchanged urokinase plasminogen activator plasma levels compared with control subjects at 32 weeks of gestation; lower plasminogen activator inhibitor type 2 (P < 0.01) and no different plasminogen activator inhibitor type 1 concentrations were observed compared to control subjects at 32 weeks of gestation. In the arterial and venous umbilical cord plasma of patients, plasminogen activator inhibitor type 1 levels were significantly higher(P <.01) compared with control subjects at 32 weeks of gestation, although urokinase plasminogen activator levels in arterial and venous umbilical cord plasma (P < 0.01) were significantly lower.

CONCLUSION

Lower plasminogen activator inhibitor type 2 levels are associated with placental insufficiency, and higher tissue plasminogen activator levels are associated with endothelial dysfunction in patients with severe preeclampsia. The higher plasminogen activator inhibitor type 1 levels and lower urokinase plasminogen activator levels in umbilical cord of these patients are suggestive of decreased fibrinolysis in the fetal circulation.

A longitudinal study of biochemical variables in women at risk of preeclampsia

OBJECTIVE

The purpose of this study was to characterize gestational profiles of biochemical markers that are associated with preeclampsia in the blood of pregnant women in whom preeclampsia developed later and to compare these markers with the markers of women who were delivered of small-for-gestational-age infants without preeclampsia and with women who were at low risk for the development of preeclampsia.

STUDY DESIGN

This was a prospective case control study. The subjects were women at risk of preeclampsia who were enrolled in the placebo arm of a clinical trial. Indices of antioxidant status, oxidative stress, placental and endothelial function, and serum lipid concentrations were evaluated from 20 weeks of gestation until delivery in 21 women in whom preeclampsia developed later, in 17 women without preeclampsia who were delivered of small-for-gestational-age infants, and in 27 women who were at low risk for the development of preeclampsia.

RESULTS

Ascorbic acid was reduced early in preeclampsia and small-for-gestational-age pregnancies. Leptin, placenta growth factor, the plasminogen activator inhibitor (PAI-1)/PAI-2 ratio, and uric acid were predictive of the development of preeclampsia.

CONCLUSION

Gestational profiles of several markers were abnormal in the group with preeclampsia, and some of the markers that may prove useful in the selective prediction of preeclampsia were identified.

Identification of plasminogen activator inhibitor-2 as a gastrin-regulated gene: Role of Rho GTPase and menin

BACKGROUND & AIMS

The gastric hormone gastrin regulates acid secretion, gene expression, and the functional development and cellular composition of the gastric mucosa. Using a gene array, we sought to identify major, novel, gastrin-regulated genes.

METHODS

A cancer gene array was probed with samples from the gastric cancer cell line AGS, expressing the gastrin-cholecystokinin(B) receptor and stimulated with gastrin. The expression of gastrin-regulated genes was further characterized by Western blots and enzyme-linked immunosorbent assay in tissue and blood of hypergastrinemic patients. Gene expression was studied using promoter-luciferase reporter constructs.

RESULTS

Plasminogen activator inhibitor 2 (PAI-2) was identified as a major, previously unknown target of gastrin in the gastric cancer cell line AGS. The relevance was confirmed by showing elevated tissue and plasma PAI-2 in hypergastrinemic patients (pernicious anemia and multiple endocrine neoplasia type 1). PAI-2 promoter-luciferase constructs showed that gastrin stimulated expression via pathways involving Galpha and Gbetagamma subunits, protein kinase C, RhoA, and the transcription factors CREB and AP1. The tumor suppressor menin inhibited transcription. In addition, gastrin stimulated expression in adjacent cells via a paracrine mechanism involving protein kinase C and RhoA but not CREB.

CONCLUSIONS

A gene array showed PAI-2 to be a novel gastrin-regulated gene, stimulated in part through CREB and AP-1 and inhibited by the tumor suppressor menin.

Altered plasma concentrations of leptin, transforming growth factor-beta(1) and plasminogen activator inhibitor type 2 at 18 weeks of gestation in women destined to develop pre-eclampsia. Circulating markers of disturbed placentation?

BACKGROUND

In many pre-eclamptic women the placentation process seems to be disturbed. Our objective was to investigate if disturbed placentation in pre-eclamptic women may be recognized in early second trimester as altered plasma levels of factors involved in the formation of the uteroplacental unit.

METHODS

In a prospective study of 2190 pregnant women we compared plasma leptin, transforming growth factor-beta(1) (TGF-beta(1)) and plasminogen activator inhibitor type 2 (PAI-2) concentrations at 18 weeks' gestation in 71 women with subsequent pre-eclampsia and 71 controls matched for age, parity and first trimester body mass index.

RESULTS

Leptin and TGF-beta(1) concentrations were lower and PAI-2 concentration higher in women destined to develop pre-eclampsia relative to controls (leptin: median (25-75 percentiles): 19.0 (14.5-29.0) vs 25.0 (16.0-35.0) ng/ml (p =0.03), TGF-beta(1): 3.2 (2.0-6.1) vs 5.3 (3.8-7.1) ng/ml (P=0.01) and PAI-2: 78.8 (65.1-118.1) vs 67.6 (61.6-79.6) ng/ml (P=0.002)). OR (95 per cent CI) for pre-eclampsia for women in the upper quartile compared to women in the lower quartile were: leptin: 0.2 (0.03-0.7), TGF-beta(1): 0.2 (0.08-0.7) and PAI-2: 3.1 (1.2-8.2).

CONCLUSIONS

Altered plasma concentrations levels of factors involved in the process of placentation in women destined to develop pre-eclampsia, indicate that disturbed formation of the uteroplacental unit is reflected in the maternal circulation before 20 weeks' gestation.

Placenta and myometrium--the two main sources of fibrinolytic components during pregnancy

OBJECTIVES

Placenta is a known source of some fibrinolytic components in pregnancy. The aim of the present study is to find out whether myometrium can be a parallel source.

STUDY DESIGN

The study group consisted of 34 women (16 primaparas and 18 multiparas, 39.0 +/- 0.2 years) in the 36-40th week of gestation with some obstetric complications: preeclampsia - 11, fetal distress - 9, breech presentation - 3, placenta previa - 1, repeat caesarean birth - 10 cases (20 women were the control group). The strips of myometrium as well as samples of venous blood and placenta were collected at the time of caesarean section. The tissue extracts were prepared. The components of the plasminogen activator system were measured, i.e. tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), plasminogen activator inhibitor 1 (PAI-1) and plasminogen activator inhibitor 2 (PAI-2). An immunoenzymatic method (ELISA) was used. Spearman and Pearson's correlation coefficients were the main tools of the statistical analysis.

RESULTS

The concentration of the fibrinolytic components in blood plasma, placenta and myometrium were as follows (ng/mg of total protein): tPA: 0.15 +/- 0.07 (blood plasma), 0.12 +/- 0.05 (placenta), and 1.42 +/- 1.02 (myometrium); uPA: 0.01 +/- 0.005 (blood plasma), 1.09 +/- 0.25 (placenta), and 0.52 +/- 0.13 (myometrium); PAI-1: 2.86 +/- 0.90 (blood plasma), 30.67 +/- 9.31 (placenta), and 22.29 +/- 11.29 (myometrium); PAI-2: 2.86 +/- 0.90 (blood plasma), 750.89 +/- 170.29 (placenta), and 24.84 +/- 8.03 (myometrium).

CONCLUSION

Besides placenta, myometrium is another important source of fibrinolytic components in pregnancy.

Expansion of the fraction of Th1 cells in women with preeclampsia: inverse correlation between the percentage of Th1 cells and the plasma level of PAI-2

PROBLEM

The fractions of Th1 cells and Tcl cells may be increased in preeclamptic women compared with healthy pregnant women.

METHOD OF STUDY

Eleven healthy non-pregnant women, nine healthy pregnant women (34.1+/-3.1 weeks of gestation), and 10 women with preeclampsia (32.0+/-5.4 weeks) were studied. The fractions of Th1 cells, Th2 cells, Tc1 cells, and Tc2 cells in the peripheral blood mononuclear cells were determined using a three-color flow cytometric technique. The concentrations of plasma plasminogen activator inhibitor-2 (PAI-2) were simultaneously determined.

RESULTS

The fraction of Thl cells was significantly larger in women with preeclampsia (18.7+/-5.2%) than in normal pregnant women (11.0+/-5.7%), and it increased with a decrease in the PAI-2 level (r = -0.706, P = 0.002), which was significantly lower in preeclamptic women (83.4+/-46.8 ng/mL) than in normal pregnant women (225.3+/-82.0 ng/mL). The fraction of Tc1 cells increased with increases in the fraction of Th1 cells (r=0.657. P<0.001) and the ratio of Th1-to-Th2 cells (r=0.535, P=0.002). The ratio of Tc1-to-Tc2 cells also increased with an increase in the ratio of Th1-to-Th2 cells (r = 0.394, P = 0.031).

CONCLUSIONS

The fraction of Th1 cells appears to be expanded in women with preeclampsia compared with healthy pregnant women.

[Serine protease inhibitors in plasma of patients with ulcerative colitis]

Serine protease inhibitors (serpins) are the important factors regulating hemostasis and inflammatory mediators activity. The aim of this study was to determine relationships between plasma serine protease inhibitors activities and the course of ulcerative colitis (uc).

PATIENTS AND METHODS

42 patients with uc, 21 in active and 21 in inactive disease phase, and 26 healthy persons (control group) were studied. In all investigated persons activities of alpha 1-proteinase inhibitor (alpha 1-PI), alpha 2-macroglobulin (alpha 2-M), alpha 2-antiplasmin (alpha 2-AP), antithrombin III (ATIII) and plasminogen activator inhibitor type 1 (PAI-1) were determined.

RESULTS

Patients with uc had higher level of alpha 1-PI than control group. In patients with active uc lower alpha 2-M activity was found than in patients with us remission. Alpha 2-M activity below 100% had 58% sensitivity and 71% specificity, and predictive value (odds ratio = 6.25) for histologic appearance of active uc. The correlation between alpha 2-M value and uc activity and time of symptoms duration before the study start was found. Patients with inflammatory process beyond sigmoid had lower alpha 2-AP activity than patients with less extended inflammatory process.

CONCLUSIONS

Inflammatory process in large bowel changed the level of plasma serine protease inhibitors activities, what was a result of acute phase reaction (alpha 1-PI) and inhibitors consumption in inflammatory processes (alpha 2-M, alpha 2-AP).

Outer membrane vesicles from Neisseria meningitidis: effects on tissue factor and plasminogen activator inhibitor-2 production in human monocytes

Lipopolysaccharide-containing outer membrane vesicles (OMV-LPS) which are spontaneously released from Neisseria meningitidis during logarithmic growth were studied for their ability to induce procoagulant (tissue factor), profibrinolytic (urokinase-type plasminogen activator) and antifibrinolytic (plasminogen activator inhibitor-2) factors in purified human monocytes. Cell-associated tissue factor was 5.0-fold (n=5) increased, peaking after 8 h, in the presence of OMV-LPS (1 microg/ml, final concentration). Plasminogen activator inhibitor-2 release from monocytes was maximal after 24 h OMV-LPS (1 microg/ml) stimulation and 13.7-fold (n=5) increased compared to controls; whereas urokinase-type plasminogen activator antigen in culture medium remained uninfluenced by OMV-LPS. In conclusion, these OMV-induced imbalances favor fibrin deposition in the monocyte microenvironment and is probably of great importance in the development of disseminated intravascular coagulation, microthrombosis and organ dysfunction related to fulminant meningococcal septicemia.

Abnormal levels of urokinase plasminogen activator protein and tissue plasminogen activator activity in human aortic aneurysms

OBJECTIVE

To measure the concentrations and activities of plasminogen activators and plasminogen activator inhibitors in human abdominal aneurysms.

DESIGN

Laboratory study.

SETTING

University hospital, Sweden.

MATERIAL

Biopsy specimens from 12 abdominal aortic aneurysms and 8 normal aortas (controls). INTRERVENTIONS: Tissues were homogenised and eluted. The supernatants were assayed for antigens of tissue and urokinase plasminogen activator and plasminogen activator inhibitor 1 and 2. The activities of tissue plasminogen activator and plasminogen activator inhibitor-1 were assayed by ELISA. Frozen sections were immunostained for tissue and urokinase plasminogen activators and for plasminogen activator inhibitor-1.

MAIN OUTCOME MEASURES

Concentrations and activities of these activators and inhibitors.

RESULTS

The concentration of urokinase plasminogen activator antigen was higher in aneurysmal walls than in normal aortas; it was detected immunohistochemically in aneurysmal but not in normal aortas. The concentration (and the detection immunohistochemically) of tissue plasminogen activator was equal in aneurysmal and normal aortas, but its activity was reduced in the aneurysmal wall. Plasminogen activator inhibitor-1 did not differ significantly between the groups.

CONCLUSIONS

Urokinase plasminogen activator may be responsible for the digestion of the media of the aorta and the development of an aneurysm. Reduced activity of tissue plasminogen activator may be responsible for thrombosis in the aneurysm.

Plasminogen activators (t-PA and u-PA) and plasminogen activators inhibitors (PAI-1 and PAI-2) in some myeloproliferative syndromes

INTRODUCTION

Clinical observations and laboratory data indicate that patients with myeloproliferative syndrome (MPS) have hemostasis disorders that manifest with haemorrhagic diathesis or thrombotic disease. The role of fibrinolytic system is not clear in the pathomechanism of the disorders. In the study we aimed to evaluate fibrinolysis system in blood plasma of the patients with selected myeloproliferative syndromes on the basis of examinations of plasminogen activators (tissue--t-PA and urokinase-type--u-PA) and type 1 and type 2 plasminogen activator inhibitors (PAI-1 and PAI-2).

MATERIAL AND METHODS

Forty-two patients (F/M 28/14) aged 36-78 years (average age--54 years) were enrolled into the study. Among the patients were 20 individuals with chronic myeloid leukaemia (CML), 17 with essential thrombocytemia (ET) and 5 with myelofibrosis (MF) treated in Provincial Haematological Outpatient Clinic in Bydgoszcz. Forty healthy volunteers (F/M 30/10) aged 24-65 (average 53) were included in control group. In citrate venous blood, the following parameters were determined: concentrations of antigen t-PA, u-PA, PAI-1, PAI-2, concentration of plasmin-alpha-2-antiplasmin complexes (PAP) determined with the use of ELISA technique, PAI-1 activity with amidolytic method, euglobulin lysis time (ELT) according to Kowarzyk-Buluk and fibrinogen/fibrin degradation products (FDP) concentration with the use of Merskey's method.

RESULTS

Performed evaluations show that besides normal ELT elevated concentrations of FDP and PAP complexes occur in the blood of patients with myeloproliferative syndromes (MPS.). In studied myeloproliferative syndromes, high concentration of PAI-1 Ag and very low activity of PAI-1 were observed. In the patients with MPS intensified plasminogenesis and increased fibrin degradation were demonstrated. The role of granulocyte elastase is considered in activation of fibrinolysis system.

Larger and more invasive colorectal carcinoma contains larger amounts of plasminogen activator inhibitor type 1 and its relative ratio over urokinase receptor correlates well with tumor size

BACKGROUND

Considering recent findings that both urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitors (PAIs) are involved in tumor growth through an urokinase-type plasminogen activator (uPA) activity-independent mechanism, the relation between the presence of these factors in tumor tissue and the clinicopathologic variables in colorectal carcinoma was reevaluated.

METHODS

In 100 colorectal carcinoma patients, antigen levels of u-PA, uPAR, and PAI-1 and PAI-2 were assayed in both tumor tissues and their normal counterparts. Plasma levels of soluble uPAR also were determined.

RESULTS

All uPAR, uPA, PAI-1, and PAI-2 antigen levels in tumor tissue were significantly higher than those in normal tissue. Levels of both uPAR and PAI-1 were significantly higher (3.09 +/- 1.37 and 6.63 +/- 7.49, respectively) in large tumors (>/=50 mm in greatest dimension) than those in smaller tumors (< 50 mm) (2.50 +/- 1.07 and 2.72 +/- 2.70, respectively) (P < 0.05). Significant positive correlation coefficients (r) were obtained between tumor size and the calculated ratios of PAI-1/uPAR (r = 0.490; P < 0.0001) and PAI-1/uPA (r = 0. 469; P < 0.0001). In addition to liver metastases (P = 0.004) and lymph node involvement (P = 0.04), high levels of uPAR (P = 0.05) also were found to be of independent prognostic value by multivariate analysis.

CONCLUSIONS

Higher expression of uPAR was related to poor prognosis of patients with colorectal carcinoma and excess amounts of PAI-1 over uPAR or uPAR-bound uPA appeared to play an important role in tumor progression.

Diagnostic and prognostic values of plasma levels of fibrinolytic markers in ovarian cancer

OBJECTIVE

The aim of this study was to find out whether any of the fibrinolytic parameters could be used as tumor markers in predicting the prognosis of ovarian cancers.

MATERIALS AND METHODS

In the present study, we determined the plasma concentrations of tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1), PAI-2, and uPA receptor (uPAR) in 25 patients with ovarian cancer, 16 patients with benign gynecologic tumor or inflammation, and 36 healthy controls in order to find out whether the plasma levels of these markers could be used to evaluate the prognostic value in patients with gynecologic cancers. We also determined two tissue concentrations of malignant tumor (one was at the tumor site itself and the other at the cut-end tissue of the tumor, which was expected to be free of tumor) in order to see the correlation between plasma and tissue concentrations.

RESULTS

Plasma PAI-1 was significantly higher in patients with malignancy than in the healthy controls (P = 0.0001). There was no significant correlation between plasma and tissue concentrations, either tumor tissue or cut-end tissue, of the same parameters. Tissue concentrations of uPA, PAI-1, and PAI-2 were significantly higher and tPA significantly lower in the malignant tumor tissue than in the cut-end tissue in the patients with ovarian cancer (P = 0.014, 0.03, 0.002, and 0.01, respectively). Plasma PAI-1 was significantly higher in patients in the late stage of ovarian cancer than in the early stages and in the controls.

CONCLUSION

From our study, we concluded that plasma levels of PAI-1 were correlated with the presence of malignant ovarian cancer and higher stage of disease.

Effect of antioxidants on the occurrence of pre-eclampsia in women at increased risk: a randomised trial

BACKGROUND

Oxidative stress has been implicated in the pathophysiology of pre-eclampsia. This randomised controlled trial investigated the effect of supplementation with vitamins C and E in women at increased risk of the disorder on plasma markers of vascular endothelial activation and placental insufficiency and the occurrence of pre-eclampsia.

METHODS

283 women were identified as being at increased risk of pre-eclampsia by abnormal two-stage uterine-artery doppler analysis or a previous history of the disorder and were randomly assigned vitamin C (1000 mg/day) and vitamin E (400 IU/day) or placebo at 16-22 weeks' gestation. Plasma markers of endothelial activation (plasminogen-activator inhibitor 1 [PAI-1]) and placental dysfunction (PAI-2) were measured every month until delivery. Pre-eclampsia was assessed by the development of proteinuric hypertension. Analyses were done by intention to treat, and in the cohort who completed the study.

FINDINGS

Supplementation with vitamins C and E was associated with a 21% decrease in the PAI-1/PAI-2 ratio during gestation (95% CI 4-35, p=0.015). In the intention-to-treat cohort, pre-eclampsia occurred in 24 (17%) of 142 women in the placebo group and 11 (8%) of 141 in the vitamin group (adjusted odds ratio 0.39 [0.17-0.90], p=0.02). In the cohort who completed the study (81 placebo group, 79 vitamin group), the odds ratio for pre-eclampsia was 0.24 (0.08-0.70, p=0.002).

INTERPRETATION

Supplementation with vitamins C and E may be beneficial in the prevention of pre-eclampsia in women at increased risk of the disease. Multicentre trials are needed to show whether vitamin supplementation affects the occurrence of pre-eclampsia in low-risk women and to confirm our results in larger groups of high-risk women from different populations.

The relationship between the onset of labor mechanisms and the hemostatic system

The relationship between onset of labor and the hemostatic system was evaluated in 38 pregnant women. The hemostatic system consists of blood coagulation, kinin-kallikrein system, the fibrinolytic system, and platelet function. The most prominent changes take place in the kinin-kallikrein system. After the onset of labor, prekallikrein decreases rapidly which may trigger changes in blood coagulation and the fibrinolytic system. Platelet hemostatic capacity (PHC) was also measured using the PFA-100 (platelet function analyzer) system. Closure times (CT) were shorter during pregnancy, compared to non-pregnant controls, suggesting an increase in PHC. Platelet aggregation by ADP at the end of pregnancy was decreased at the onset of labor. At the same time a slight increase in FDP (fibrin degeneration product) was also seen. While FDP increased, platelet aggregation decreased, which seems to suggest FDP inhibits platelet aggregation. In this manner, these three systems(kinin-kallikrein system, blood coagulation, and fibrinolytic system) and platelet aggregation are closely interrelated, possibly affecting uterine contractility during pregnancy and the onset of labor.

The effect of cyclosporine on regulators of fibrinolysis in plasma from renal allograft recipients

Fibrinolytic disturbances are thought to play an important role in processes leading to deterioration of renal allograft function. We investigated the effect of CsA therapy on the regulation of fibrinolysis in kidney graft recipients by measuring plasma concentration and activity of plasminogen activators (tPA, uPA) and their inhibitors (PAI-1, 2). We found an increase in tPA activity and in PAI-1 concentration as well as a decrease in PAI-1 activity in renal allograft recipients as compared to healthy controls, but did not confirm a correlation between these observations and CsA administration. tPA and PAI-2 concentrations as well as uPA activity did not significantly differ between the studied groups. We showed a significant decrease in uPA plasma concentration in patients treated with azathioprine. The significance of this finding is unknown.

Platelet hemostatic capacity (PHC) and fibrinolytic inhibitors during pregnancy

Platelet hemostatic capacity (PHC) was measured in blood from pregnant patients during all three trimesters using the PFA-100 system. Closure times were shorter with both cartridge systems during pregnancy, compared to non-pregnant controls, suggesting increased PHC. Thrombin/antithrombin (TAT) complex and prothrombin fragment 1 + 2 (F 1+2) levels were elevated during pregnancy and increased over time. Also, plasma levels of plasminogen activator inhibitor 1 and 2 (PAI-1, PAI-2) increased during pregnancy. The data suggest increased coagulability during pregnancy. It is suggested that estrogen may play a role in this state of hypercoagulability. Seven days after delivery all of the measured parameters, except TAT levels, were again within normal range.

Significance of the plasminogen activator inhibitor of placental type (PAI-2) in pregnancy

Marked changes in the hemostasis system, especially increases in PAI-2, are observed during pregnancy and at delivery. This inhibitor is produced by placental trophoblasts and by macrophages. PAI-2 occurs in two forms, a LMW and a HMW form. LMW PAI-2 is intracellular, HMW PAI-2 is secreted. PAI-2 inhibits both u-PA and two-chain t-PA. PAI-2 seems to be involved in the processes of invasion and remodeling of fetal and uterine tissues. It may protect against premature placental separation and secure hemostasis at parturition. Excess levels of PAI-2 in amniotic fluid may protect membranes from premature rupture. An imbalance between fibrinolytic activators and inhibitors may also be related to intracranial hemorrhage in premature infants. During preeclampsia t-PA and PAI-1 levels are markedly increased in plasma, and in cases of intrauterine growth retardation, u-PA and PAI-2 levels are decreased. While elevated PAI-1 concentrations might be helpful markers of severity of preeclampsia, decreased PAI-2 levels seem to indicate decreased placental function and intrauterine growth retardation.

Tissue plasminogen activator reduces intraperitoneal adhesion after intestinal resection in rats

We investigated whether tissue plasminogen activator (tPA), a plasma serine protease that catalyzes the initial and rate-limiting step in fibrinolysis, inhibits postoperative intraperitoneal adhesion formation in rats. Male Wistar rats weighing 200 to 250 g underwent laparotomy with a 15-cm intestinal resection and reanastomosis; the intestinal serosa was scratched to induce adhesion formation. The rats were divided into three groups: the control group received no medication; the normal saline group received peritoneal irrigation with 6 mL normal saline intraoperatively; and the tPA group received peritoneal irrigation with 6 mL tPA solution (5 mg/L) intraoperatively. The rats were killed 7 or 14 days later. The scores (severity of adhesion, 0-3 point scale), strength, and extent of fibrous bands were recorded on the day the rats were killed. Wound strength was measured using an Instron tensionmeter immediately after the rats were killed. The concentrations of plasma tPA and plasminogen activator inhibitor (PAI)-1 and -2 were measured. The scores and strength of fibrous bands in the tPA group were lower than those in the control and saline groups whereas wound strength was similar in all groups. The plasma tPA concentration was significantly higher and the plasma PAI-1 and PAI-2 concentrations were significantly lower in the tPA group than in the control and saline groups on the 7th and 14th postoperative days. Our findings suggest that tPA can reduce the incidence of postoperative intraperitoneal adhesions without impairing wound healing.

Coagulation and fibrinolytic parameters in normal pregnancy and in pregnancy complicated by intrauterine growth retardation

The objective of this article is to evaluate the plasma levels of coagulation and fibrinolysis parameters in the third trimester of gestation and 72 hr postdelivery. Antithrombin III (ATIII), thrombin-antithrombin III complexes (TAT), heparin cofactor II (HCII), protein C (PC), protein S (PS), tissue plasminogen activator (t-PA), D-dimer, and plasminogen activator inhibitors (PAI-1 and PAI-2) levels in uncomplicated pregnancies and in pregnancies complicated by intrauterine growth retardation (IUGR) have been determined. Normal pregnant women (n = 63) and women whose was complicated by IUGR (n = 10) formed the study population. Coagulation and fibrinolysis parameters were estimated using commercial tests. There were no differences in ATIII, HCII, and PS levels between normal and IUGR pregnancies. TAT, t-PA, and D-dimer levels were higher in IUGR pregnancy than in the uncomplicated pregnancy group. PAI-1 and PAI-2 were found depressed in IUGR pregnancy when compared with normal pregnancy. Changes in coagulation and fibrinolytic systems occur in plasma of women with pregnancies complicated by IUGR. The results suggest an activation of the coagulation system in pregnancies complicated by IUGR. Reduced PAI-2 and high TAT levels correlate with birth weight. In IUGR pregnancies a hypercoagulative state with hyperfibrinolytic compensatory mechanisms is suggested.

[Plasminogen activator inhibitor (PAI-1) and markers of endothelial dysfunction in patients with diabetes mellitus]

The authors examined 25 patients with diabetes mellitus type 2 (NIDDM) without vascular complications, treated by sulphonyl urea preparations, 12 hyperinsulinaemic (HI) non-diabetic subjects and 11 normoinsulinaemic healthy subject s. Patients with NIDDM and HI non-diabetics had significantly elevated PAI-1 levels which correlated with the C-peptide level (r = 0.519, p < 0.001), triacylglycerols (TG) (r = 0.685, p < 0.001), BMI (r = 0.607, p < 0.001) and levels of endothelial markers such as von Willebrand s factor and thrombomodulin (TM). In the group of patients with NIDDM no relationship of PAI-1 and C-peptide was found and a significant correlation was found with TM levels (r = 0.609, p = 0.001) and TG levels (r = 0.476, p = 0.046). The results suggest that the endothelial department has an effect on the regulation of PAI-1 levels in patients with NIDDM.

Markers of intravascular coagulation and fibrinolysis in preeclampsia: association with intrauterine growth retardation

BACKGROUND

Alterations in blood coagulation and fibrinolysis are believed to play an important role in the pathogenesis of preeclampsia. Hypercoagulability may be associated with features seen in preeclampsia, such as fibrin deposition in various organs, consumptive thrombocytopenia, and placental hypoperfusion, insufficiency and infarction.

METHODS

In this cohort study, we compared the plasma levels of markers of blood coagulation and fibrinolysis in preeclamptic women to normotensive, pregnant controls. We also studied the association between these markers and intrauterine growth retardation (IUGR).

RESULTS

In both mild and severe preeclampsia, the mean plasma concentrations of thrombin-antithrombin III complex (TAT) and plasminogen activator inhibitor type 1 (PAI-1) activity were significantly increased, while fibrinogen, antithrombin III (ATIII) and plasminogen activator inhibitor type-2 (PAI-2) antigen levels were significantly reduced compared to controls. Plasma D-dimer concentration was significantly higher in severe, but not in mild preeclampsia compared to the controls. The plasma level of fibrin monomer was similar in patients and controls. Patients with preeclampsia delivering growth retarded infants had significantly lower PAI-1 activity and PAI-2 antigen concentrations in plasma than the remaining preeclamptic women.

CONCLUSION

We found evidence of increased intravascular coagulation and fibrin turnover in preeclampsia. Low PAI-2 antigen plasma levels were associated with severe preeclampsia and IUGR.

Plasminogen activators and plasminogen activator inhibitors in plasma of premature and term newborns

OBJECTIVE

To compare the plasminogen activators (tPA, uPA) and their inhibitors (PAI-1, PAI-2) at different gestational ages, related to levels in women at term and non-pregnant women.

METHODS

Blood samples were obtained by puncture of the umbilical cord vein, in gestational weeks 39-40 (n = 21), 30-32 (n = 15), and 27-29 (n = 9). Analyses of PA and PAI antigen concentrations and of PAI-1 activity were performed.

RESULTS

The mean tPA antigen level in term newborn infants was 14.5 micrograms/l compared to the premature newborns (7.0 micrograms/l), women at term (7.5 micrograms/l) and non-pregnant women (2.3 micrograms/l). PAI-1 activity and PAI-2 antigen concentrations were also higher in term newborn than in premature infants.

CONCLUSIONS

The plasma levels of the plasminogen activators and inhibitors are higher in term newborn compared with premature newborn infants, reflecting maturation of protein synthesis.

Abnormal expression of plasminogen activator inhibitors in patients with gestational trophoblastic disease

We previously reported significantly elevated levels of plasminogen activator inhibitor type 1 (PAI-1) in plasma and placenta from pregnant women with severe pre-eclampsia, and pre-eclampsia is a frequent problem in molar pregnancies. As increases in PAI-1 may contribute to the placental alterations that occur in pre-eclampsia, we have begun to investigate changes in PAI-1 as well as PAI-2 and several other components of the fibrinolytic system in patients with trophoblastic disease. Significant increases in plasma PAI-1 and decreases in plasma PAI-2 levels were observed in molar pregnancies when compared with the levels in normal pregnant women of similar gestational age. PAI-1 antigen levels also were increased, and PAI-2 levels were decreased in placenta from women with molar pregnancies compared with placenta obtained by spontaneous abortion. Immunohistochemical analysis revealed strong positive and specific staining of PAI-1 in trophoblastic epithelium in molar pregnancies and relatively weak staining of PAI-2. No association between the distribution of PAI-1 and vitronectin was found, and no specific signal for tissue type PA, urokinase type PA, tumor necrosis factor-alpha, or interleukin-1 was detected. In situ hybridization revealed an increase in PAI-1 but not PAI-2 mRNAs in placenta from molar pregnancies in comparison with placenta from abortions. These results demonstrate increased PAI-1 protein and mRNA in trophoblastic disease and suggest that localized elevated levels of PAI-1 may contribute to the hemostatic problems associated with this disorder.

On the affinity between the plasminogen activator inhibitor type 2 and apolipoprotein A1

The plasminogen activator inhibitor type 2 (PAI-2) is present in its high molecular weight, glycosylated form in pregnancy plasma. When the protein was purified from retroplacental blood by immunoaffinity chromatography on a PAI-2 antibody column and the retained material was further fractionated by gel filtration chromatography, it was always contaminated by apolipoprotein A1, the latter protein being identified by its N-terminal sequence, molecular weight in SDS-PAGE and immunological properties. The co-purification of the two proteins seemed to indicate a strong affinity between them, suggesting apolipoprotein A1 to be a carrier protein for this PAI-2 form. Further investigation to check this hypothesis showed that the binding of apolipoprotein A1 to the immunoaffinity support was PAI-2-independent and caused by a general surface affinity. This finding was corroborated by a study of the microtitre plate binding properties of the proteins. Pure, high molecular weight PAI 2 did not bind to apolipoprotein A1-coated wells, but the latter protein bound to coated as well as to uncoated wells. Thus, there is no evidence for a specific binding between the two proteins.

Relationship of urokinase type plasminogen activator, plasminogen activator inhibitor type 1 and activated protein C in fibrinolysis of human placenta

Suppression of the fibrinolytic activity plays an important role in the prevention of hemorrhage during pregnancy and labor. A hypofibrinolytic and hypercoagulable state may be established in the placenta during pregnancy. However, little infraction is present in the normal placenta. This evidence shows that placenta maintains the fibrinolytic activity in spite of hypercoagulable state. As there is a high amount of APC in the placenta, APC is thought to be involved in fibrinolysis of placenta. Thus, we studied the role of APC on fibrinolysis in placenta. (1) uPA activity of cell membrane reappears after incubation with uPA/PAI-1 complex and a large amount of APC by flow cytometry, (2) APC was made PAI-1/APC complex after incubation of uPA/PAI-1 complex with APC. Our results suggest that APC is the important substance for fibrinolysis in the placenta by decreasing of PAI activity.

Fibrinolysis during normal pregnancy and severe preeclampsia relationships between plasma levels of plasminogen activators and inhibitors

The antigen levels of plasminogen activator inhibitor type 1 (PAI-1), plasminogen activator inhibitor type 2 (PAI-2), tissue-type plasminogen activator (t-PA), and urokinase-type plasminogen activator (u-PA) were measured during pregnancy and severe preeclampsia. The PAI-1 and PAI-2 antigen levels increased linearly during pregnancy and promptly returned to the level of non-pregnant women after delivery. The t-PA and u-PA antigen levels increased slowly and linearly during pregnancy. In severe preeclampsia, the PAI-2 antigen level was lower than that observed during the 3rd trimester of normal pregnancy, and the t-PA antigen level was higher than that during the 3rd trimester of normal pregnancy. Immunohistochemical examination of placental tissue showed that the PAI-2 and u-PA antigens were localized in syncytiotrophoblasts. In severe preeclampsia, the PAI-2 and u-PA antigens in placental tissue did not stain as clearly as during the 3rd trimester of normal pregnancy. The PAI-2 and u-PA antigen levels showed a positive correlation with birth weight. Therefore, PAI-2 may be an important marker of placental function and abnormality in pregnancies.

Tissue plasminogen activator and plasminogen activator inhibitors of type 1 and type 2 in the plasma of parturient women

Changes in the fibrinolytic system of parturient women have so far been only partially documented. Our main questions were whether and how the concentration of tissue plasminogen activator (tPA) and plasminogen activator inhibitors of type 1 (PAI-1) and type 2 (PAI-2) change in the plasma throughout normal labor. The study group consisted of 38 women with normal pregnancy, delivering at term. The concentration of antigens tPA, PAI-1 and PAI-2 in plasma was tested by enzyme-linked immuno-sorbent assay method, and the activity of PAI-1 by plasmin method. Results were analysed statistically. During labor the level of tPA antigen increases over two times: from 9.3 +/- 4.3 ng/ml before labor, to 23.3 +/- 9.6 ng/ml in the second stage of labor. Changes of PAI-1 antigen as well as its activity though noticeable, were not statistically significant. PAI-2 antigen level increased significantly in the third stage (146.3 +/- 58.7 ng/ml before labor, and 212.2 +/- 75.0 ng/ml after placenta expulsion). In summary the more significant change in the fibrinolytic system during labor is an increase of the level of tPA and PAI-2 antigens, but their peaks appear in different stages of labor. The predominance of PAIs over tPA is maintained throughout the whole labor, though on a lower level as can be inferred from the tPA/PAIs ratio.

Inhibitors of plasminogen activator in neutrophils and mononuclear cells from septic patients

Leucocytes, both polymorphs and mononuclear cells, play a variety of roles in the evolution of human response to sepsis, both local and generalised. In this study, inhibitors of plasminogen activator were measured in leucocytes from normal and septic patients. Plasminogen activator inhibitor-1 (PAI-1) was identified in polymorphs from normal individuals and levels rose significantly in polymorphs from septic patients: neutrophils from normal subjects did not contain PAI-2 but this protein was detectable in significant quantities in polymorph preparations from septic patients. In contrast, mononuclear cells from normal and septic patients contained no detectable quantities of PAI-1. Significant amounts of PAI-2 were present in normal mononuclear cells, and the levels rose significantly in monocytes from septic patients. PAI-2 is thus here identified in human subjects, distinct from those with pregnancy or malignancy, as playing a role in a pathological process. The increased levels of both inhibitors produced by leucocytes may clearly contribute directly to the persistence of fibrin, a characteristic feature of the response to infection, local or general; they may thus participate in successful localisation of infections (abscess formation etc.) and in the evolution of the major systemic complications of disseminated sepsis characterised by microvascular occlusion by fibrin such as renal failure, shock lung or digital ischaemia.

Blood and tissue fibrinolytic profiles in patients with colorectal carcinoma

In patients with colorectal cancer, profound alterations of the plasminogen activator system have been described at the tumor level, but conflicting results have been obtained for fibrinolytic parameters in plasma. Components of the fibrinolytic system, including tissue-type and urokinase-type plasminogen activators and their inhibitors type 1 and 2, were measured in tissue and/or plasma from 41 patients with colorectal cancer and in 40 controls. Procoagulant activity of freshly isolated mononuclear cells (basal activity) and the procoagulant activity and fibrinolytic proteins produced by the cells after incubation for 18 h without exogenous stimulation were also evaluated. Malignant tissue extracts had significantly higher levels of urokinase-type plasminogen activator and plasminogen activator inhibitor-1, but lower levels of tissue-type plasminogen activator than normal mucosa. Plasminogen activator inhibitor-1 alone was higher in advanced (Dukes' stages C + D) than limited (B) tumors. Plasminogen activator inhibitor-2 was not different in malignant tissue and normal mucosa. Plasma levels of plasminogen activator inhibitor-1 antigen were significantly increased in cancer patients compared with controls, but there were no differences in tissue-type and urokinase-type plasminogen activator, in plasminogen activator inhibitor-2, and D-dimer levels. Intra-patient analysis revealed no significant correlation between tumor and plasma levels of plasminogen activators or type 1 inhibitor. Tissue-type plasminogen activator, but not the urokinase type or inhibitor type 1, was higher in venous than in arterial blood collected at the tumor site during surgery. Basal procoagulant activity of mononuclear cells and the procoagulant activity and inhibitor type-2 produced by the cells after short-term culture were comparable in patients and controls. These findings indicate that, at least in our patients with colorectal cancer, the profound changes occurring at tumor level are barely detectable in the blood. Thus, the clinical relevance of plasma fibrinolytic parameters, especially urokinase-type plasminogen activator antigen, as tumor markers in colorectal cancer remains to be established.

Increased blood flow resistance in placental circulation and levels of plasminogen activator inhibitors types 1 and 2 in severe preeclampsia

To study whether increased resistance in the placental circulation changes the plasma levels of plasminogen activators types 1 and 2 (PAI-1 and PAI-2) in severe preeclampsia, the levels of PAI-1 activity and PAI-2 antigen were determined in 33 severely preeclamptic and 22 normal pregnant women during gestational weeks 24-35. In the preeclampsia group, the Pulsatility Index (PI) of the umbilical artery was investigated with Doppler ultrasound. The levels of PAI-1 activity were higher (P < 0.01) whereas those of PAI-2 antigen were lower (P < 0.01) in the preeclampsia group than in the normal pregnancy group. The patients with abnormally high PI (high PI group) had increased PAI-1 levels (P < 0.05) and unchanged PAI-2 levels (P > 0.05), compared with those with normal PI (normal PI group). The levels of PAI-1 were positively correlated to the PI values during pregnancy weeks 34-35 only in the high PI group (r = 0.88, P < 0.05). In conclusion, high resistance in the placental circulation elevates plasma PAI-1 activity levels but does not influence PAI-2 antigen levels.

Diagnostic efficacy of plasma urokinase-type plasminogen activator and plasminogen activator inhibitor-2 in differentiation of hepatocellular carcinoma from cirrhosis

We determined the plasma antigen levels of urokinase-type plasminogen activator(u-PA) and plasminogen activator inhibitor 2(PAI-2) in 41 patients with hepatocellular carcinoma and 28 patients with different stages of liver cirrhosis. No significant differences of u-PA and PAI-2 levels were calculated between the two groups of tumor patients (HCC) and liver cirrhosis without tumor (non-HCC). Within both study groups, no significant differences were found in u-PA and PAI-2 levels of the different Child categories. Discriminative functions of both u-PA and PAI-2 (total error count estimates of 43.1% and 43.6%, respectively), were low compared to that (29.0%) of alpha-fetoprotein (AFP). The combinations of AFP and u-PA lowered the total error rate (21.9%) more than that of each marker alone. However, whether plasma u-PA and PAI-2 may be considered as a risk factor further investigation was needed and our findings raise the question as to whether these markers could be considered as useful screening markers for earlier detection of HCC in liver cirrhosis because discriminant functions of u-PA and PAI-2 were not significant. Sensitivities and specificities of u-PA and PAI-2 were also not high enough, resulting in the ranges of total diagnostic efficiency from 43% to 50%, and, from 49% to 63%, respectively, at different cut-off values. No direct relationship was detected between AFP and u-PA, between AFP and PAI-2, and between u-PA and PAI-2.

Defibrotide reduces monocyte PAI-2 and procoagulant activity

Defibrotide is a polydeoxyribonucleotide-derived anti-ischemic drug with multiple sites of action involving both plasmatic and cellular targets. This agent has been demonstrated to produce profibrinolytic, cytoprotective, and vaso-facilatory actions. Since monocytes are increased in the mediation of some of the pathophysiologic responses seen in ischemic disorders, the functional properties of these cells were investigated in experimental conditions to evaluate their behavior during resting and stimulated states. Defibrotide was supplemented in these systems to determine its modulatory action. In this investigation Defibrotide was found to decrease the PAI-1 levels and may indicate that this may be the mechanism for its profibrinolytic actions. Defibrotide was also found to reduce the procoagulant activity of monocytes in these experimental settings. Both PAI and procoagulant factors play an important role in the pathophysiology of inflammation, DIC, and ischemia. Defibrotide induced reduction of these two factors represents the mechanism whereby this agent produces its therapeutic action.

Effect of low-dose aspirin during pregnancy on fibrinolytic variables before and after parturition

OBJECTIVE

We assessed the effects of a daily oral dose of 60 to 80 mg of aspirin from 12 weeks' gestation until delivery on fibrinolytic variables before and after parturition.

STUDY DESIGN

In a prospective controlled study labor was electively induced in 24 patients, eight receiving low-dose aspirin and 16 controls. Levels were determined in maternal and cord plasma of tissue-type plasminogen activator antigen and activity, plasminogen activator inhibitor-1 antigen, plasminogen activator inhibitor activity, and plasminogen activator inhibitor-2 antigen. We also determined metabolites of vascular prostacyclin and platelet thromboxane A2.

RESULTS

The only maternal fibrinolytic variable affected by low-dose aspirin was plasminogen activator inhibitor activity, which showed a significant reduction before and after parturition of 40% and 70%, respectively, in low-dose aspirin users compared with controls. Concentrations of thromboxane B2 in women using low-dose aspirin were 7% (maternal serum) and 17% (cord serum) of values in controls, but concentrations of 6-keto-prostaglandin F1 alpha were not affected.

CONCLUSIONS

Low-dose aspirin reduces plasminogen activator inhibitor activity and platelet reactivity, but not prostacyclin synthesis, before and after parturition. The reduction in plasminogen activator inhibitor activity may be caused by inhibition of platelet reactivity.

Effect of lipoproteins on tissue factor activity and PAI-II antigen in human monocytes and macrophages

Expression of the tissue factor (TF) and the plasminogen activator inhibitor-II were induced in cultured human monocytes-macrophages by incubation with lipoproteins. Very low-density lipoprotein (VLDL) augmented the TF and PAI-II expression the most, followed by low-density lipoprotein (LDL) and a very weak effect by high-density lipoprotein (HDL). In macrophages pre-cultured for 3 days, oxidized LDL augmented the expression of TF activity in the macrophages to a greater extent than native LDL. These findings indicate that lipoproteins affect both monocytes and macrophages, and that they induce a hypercoagulable-hypofibrinolytic state. Thus hyperlipidemia may be a direct risk factor for thrombotic disease.

Plasminogen activator of urokinase type and its inhibitor of placental type in hypertensive pregnancies and in intrauterine growth retardation: possible markers of placental function

OBJECTIVE

Our purpose was to study the plasma concentrations of the plasminogen activator of urokinase type and its specific inhibitor of placental type in pregnancies complicated by hypertension or fetal growth retardation.

STUDY DESIGN

Consecutive patients with pregnancy-induced hypertension (n = 17), mild preeclampsia (n = 17), severe preeclampsia (n = 19), and intrauterine growth retardation (n = 19) were studied. Blood samples were obtained just before delivery (mean 2 days). Women with normal pregnancies (n = 40), longitudinally followed between the tenth and fortieth gestational weeks, served as a control group.

RESULTS

The plasma concentrations of the urokinase type antigen were significantly lower in women with severe preeclampsia or intrauterine growth retardation than those in women with normal pregnancies (p < 0.001). In all four groups with complicated pregnancies the antigen concentrations of the urokinase type and its inhibitor were significantly correlated with both placental weight and birth weight.

CONCLUSIONS

The plasma concentration of the urokinase type antigen would appear to reflect placental function, and both the antigen and its inhibitor concentrations are correlated with placental and fetal growth.

Increased mononuclear cell tissue factor and type-2 plasminogen activator inhibitor and reduced plasma fibrinolytic capacity in children with lymphoma

Blood clotting activation and fibrin deposition are common findings in lymphoma patients. We evaluated the capacity of peripheral blood mononuclear cells to produce procoagulant activity (PCA) and plasminogen activator inhibitor (PAI) in 12 children with newly diagnosed lymphoma (8 non-Hodgkin's, 4 Hodgkin's) and in 12 matched healthy donors. In the same subjects we also measured plasma antigen levels of tissue-type PA (t-PA), urokinase-type PA (u-PA), PAI-1, PAI-2, and D-dimer. PCA generated by mononuclear cells after incubation for 20 h at 37 degrees C was significantly higher in patients than in controls (p = 0.027). In all samples it was identified as tissue factor by functional criteria (dependence on factor VII). Moreover, culture medium obtained from patients' mononuclear cells after incubation for 20 h at 37 degrees C contained significantly higher amounts of PAI activity and PAI-2 antigen than control samples (p < 0.001). Plasma PAI-1 and t-PA antigens were significantly augmented in patients (p < 0.005), the mean increase of PAI-I being about 5 times higher than that of t-PA. Plasma levels of D-dimer were markedly increased in the patient's group (p < 0.001), whereas u-PA and PAI-2 antigens did not differ from controls. It is suggested that monocytes from lymphoma patients are endowed with functional abnormalities leading to the simultaneous expression of tissue factor and antifibrinolytic activity. These abnormalities, coupled with a reduced plasma fibrinolytic potential, could play an important pathogenetic role in blood clotting activation and fibrin deposition associated with lymphoma.

Effects of labor and delivery on fibrinolysis

Because timing of sampling is crucial in an investigation of the effects of labor and delivery on fibrinolysis we conducted a study of fibrinolytic markers in plasma of 10 healthy multiparous women in whom labor was induced, which allowed standardization of sampling times in relation to the course of labor and delivery. Blood samples were taken 5 min before the start of oxytocin infusion, at full cervical dilatation, and within 5 min after delivery of the placenta. A sample of mixed free flowing cord blood was obtained after delivery with the placenta in situ. Variables determined were tissue-type plasminogen-activator (t-PA) and the plasminogen activator inhibitors type 1 (PAI-1) and type 2 (PAI-2). The only significant change between the beginning of the induction of labor and the end of the first stage of labor was a rise in t-PA antigen (P = 0.01). All variables, except PAI-2 antigen, changed significantly after delivery of the placenta: t-PA antigen and activity showed a rise (P < 0.05), accompanied by a fall in PAI-1 antigen and activity (P < 0.01). T-PA activity in cord plasma was higher (P < 0.01) in comparison with maternal plasma concentrations at the end of the first stage of labor, t-PA antigen levels were similar, and PAI-1 antigen and activity and PAI-2 antigen were lower in cord plasma (P < 0.001). Our study shows that activation of the maternal fibrinolytic system can already be detected during labor, with a marked further increase in fibrinolytic potential after placental separation.

Haemostatic, fibrinolytic and endothelial variables in normal pregnancies and pre-eclampsia

OBJECTIVE

To determine the behaviour of the coagulation variables antithrombin III (ATIII), protein C, thrombin/antithrombin III (TATIII); fibrinolytic activity, tissue plasminogen activator antigen (t-PA), plasminogen activator inhibitors (PAI) 1 and 2, and endothelial involvement by fibronectin assay in normal and pre-eclamptic pregnancies.

DESIGN

Longitudinal and cross-sectional observational study.

SETTING

Antenatal clinic and maternity hospital.

SUBJECTS

Thirty-six primigravid normotensive caucasian patients, four of whom subsequently developed pre-eclampsia, and 12 patients with established pre-eclampsia.

MAIN OUTCOME MEASURES

Plasma levels of PAI-1, PAI-2 and t-PA antigen were determined using an ELISA technique as were TATIII complex levels of fibronectin. ATIII and protein C plasma levels were assayed using chromogenic substrate techniques.

RESULTS

PAI-1 and PAI-2 antigen levels rose progressively throughout normal pregnancy. Among the established pre-eclamptic group compared with matched normal pregnancies, the PAI-2 antigen level was significantly lower (48.5 +/- 22.8 versus 183.5 +/- 37.4; P < 0.001), the PAI-1 antigen level was significantly higher (122 +/- 34.4 versus 79.2 +/- 19.7; P < 0.001), ATIII activity was significantly lower (87.8 +/- 27.1 versus 110.9 +/- 19.3; P < 0.001) and TATIII complex levels were significantly higher (16.9 +/- 6.4 versus 10.2 +/- 5.9; P < 0.001). Among the four initially normotensive patients who subsequently developed pre-eclampsia, fibronectin levels were significantly elevated from as early as nine weeks of gestation.

CONCLUSION

Significantly elevated levels of PAI-1 and fibronectin occurring early in pregnancies that subsequently develop pre-eclampsia suggest that these variables may have predictive values. PAI-2 would seem to be a marker of placental function in pre-eclampsia while increased t-PA and TATIII complex levels reflect the severity of the condition.

Tissue plasminogen activator, plasminogen activator inhibitors, and activator-inhibitor complex in liver disease

AIMS

To identify the relative contribution of plasminogen activators, particularly tissue plasminogen activator (t-PA) and specific plasminogen activator inhibitors (PAI-1, PAI-2), to the fibrinolytic changes associated with various types of liver disease or severe chemical and physical damage to the liver.

METHODS

Platelet rich (PRP) and platelet poor plasma (PFP) from patients with alcoholic cirrhosis, primary biliary cirrhosis, hepatic malignancy, or paracetamol overdose, or who were undergoing partial hepatectomy or liver transplantation, were assayed for t-PA, PAI-1, t-PA-PAI-1 complex and PAI-2 antigen values using specific enzyme linked immunosorbent assays (ELISAs) developed in this laboratory.

RESULTS

Appreciable increases in the plasma concentration of t-PA, PAI-1, and t-PA-PAI-1 were seen in patients with alcoholic cirrhosis, primary biliary cirrhosis, and hepatic malignancy. Liver damage due to paracetamol overdose and partial hepatectomy both resulted in a striking increase in plasma PAI-1 concentration, although concentrations of t-PA and t-PA-PAI-1 complex were less affected. Concentrations of t-PA, PAI-1, and t-PA-PAI-1 complex returned to near normal values after successful liver transplantation in a patient with chronic active hepatitis. PAI-2 was also detected in several patients with chronic liver disorders.

CONCLUSIONS

Haemorrhage due to fibrinolytic bleeding is commonly associated with liver disease. The patients studied here all had appreciable increases in circulating t-PA antigen concentrations. This was associated with increased concentrations of PAI-1 antigen and t-PA-PAI-1 complex and the balance between activator and inhibitor did not result in systemic plasmin generation. Reduced PAI-1 activity in cirrhosis or a critical difference in the ratio of t-PA to PAI-1 concentrations may explain the enhanced plasminogen activator activity previously noted in cirrhosis but not metastatic disease. Reduced hepatic clearance of t-PA and t-PA-PAI-1 complex due to impaired liver function may account for increased concentrations of free and complexed t-PA.

Evaluation of plasminogen activators and plasminogen activator inhibitors in plasma and amniotic fluid in pregnancies complicated with intrauterine fetal growth retardation

Several fibrinolytic parameters were determined in plasma and amniotic fluid from normotensive pregnancies complicated by intrauterine fetal growth retardation (IUGR) and severe preeclamptic (PE) patients with IUGR and compared with data from normal pregnancies. A significant decrease in plasminogen activator type 2 (PAI-2) and urokinase levels in plasma and amniotic fluid was observed in IUGR groups in comparison with normal pregnancy. No significant differences were observed between the control and IUGR groups in relation to the other fibrinolytic parameters, except for plasma PAI type 1 and tissue-type plasminogen activator levels, which were significantly increased in the PE group. A significant positive correlation was observed between birth weight and PAI-2 levels in both plasma and amniotic fluid, but the plasma PAI-2 levels showed a higher correlation. In conclusion, these results suggest that the PAI-2 level measured in plasma is a more adequate marker of placental function than the PAI-2 level measured in amniotic fluid.

Macrophage colony-stimulating factor and granulocyte-macrophage colony-stimulating factor stimulate the synthesis of plasminogen-activator inhibitors by human monocytes

Macrophage colony-stimulating factor (M-CSF or CSF-1) and granulocyte-macrophage CSF (GM-CSF) have been shown to increase human monocyte urokinase-type plasminogen-activator (u-PA) activity with possible consequences for cell migration and tissue remodeling; because monocyte u-PA activity is likely to be controlled in part also by the PA inhibitors (PAIs) made by the cell, the effect of M-CSF and GM-CSF on human monocyte PAI-2 and PAI-1 synthesis was investigated. To this end, elutriation-purified human monocytes were treated in vitro with purified recombinant human M-CSF and GM-CSF, and PAI-2 and PAI-1 antigen and mRNA levels measured by specific enzyme-linked immunosorbent assays and Northern blot, respectively. Each CSF could enhance the protein and mRNA levels of PAI-2 and PAI-1 at similar concentrations for each product. This similar regulation of monocyte PAI expression in response to the CSFs contrasted with that found for the effects of lipopolysaccharide, transforming growth factor-beta and a glucocorticoid. Therefore, PAIs may be modulating the effects of the CSFs on monocyte u-PA activity at sites of inflammation and tissue remodeling.