Euglobulin Fibrinolytic Activity Research Articles

Fibrinolysis in insulin dependent diabetic patients with or without nephropathy

Among diabetic patients the presence of a nephropathy is associated with an increased risk of cardiovascular disease. But the prevalence and importance of the classical risk factors of cardiovascular disease among these patients do not appear to fully explain this phenomenon. An impaired fibrinolysis has been shown to be a risk factor for coronary heart disease. Therefore we have studied the fibrinolysis parameters in 31 insulin dependent diabetic patients subdivided in three groups according to their urinary albumin excretion (UAE), in normal (11 patients with UAE<30mg/day), incipient nephropathy (11 patients with UAE comprised between 30 and 300mg/day) and clinical nephropathy (9 patients). They were compared to 16 normal subjects. The three groups of patients did not differ as regard to the clinical parameters except for higher fasting free plasma insulin levels in the groups with nephropathy. Fibrinolysis parameters of the whole group of insulin dependent diabetic patients did not differ from those of the control subjects and were in the normal range. However, when diabetics were classified according to their renal status analysis of variance showed that euglobulin fibrinolytic activity tended to decrease in patients with nephropathy and the levels of plasminogen activator inhibitor (PAI-I) were significantly higher in patients with incipient or overt nephropathy. However all of these parameters remained in the normal range. When patients were considered together, a positive correlation was found between PAI-1 level and UAE, free insulin, triglyceride and ApoB level. Therefore, an impaired fibrinolysis cannot explain the propensity to cardiovascular disease of the insulin dependent diabetic patients with nephropathy. However, the slightly elevated PAI-1 levels among these patients may be attributed to either a widespread endothelial damage or to the moderate peripheral hyperinsulinism these patients exhibit.

Fasting blood coagulation and fibrinolysis of young adults unchanged by reduction in dietary fat content.

Low-fat, high-fiber diets may influence the variables of blood coagulation and fibrinolysis associated with cardiovascular morbidity. Dietary fat content has been suggested as the important determinant. This hypothesis was tested in a strictly controlled dietary study of 13 healthy individuals. They were fed two experimental diets in a 2 x 2-week crossover trial. The diets differed in fat content (39% versus 31% of total energy), whereas the fatty acid composition and the fiber content were virtually identical. We observed no significant differences between diets in terms of fasting plasma levels of factor VII coagulant activity, fibrinogen, euglobulin fibrinolytic activity, tissue-type plasminogen activator (t-PA) activity, t-PA antigen, plasminogen activator inhibitor type 1 (PAI-1) antigen, or PAI activity. Serum levels of total cholesterol, high density lipoprotein cholesterol, and triglycerides were also unaffected. In conclusion, a moderate reduction in dietary fat intake, at a fixed fatty acid composition and dietary fiber intake, did not significantly influence blood coagulation, fibrinolysis, or blood lipids in the fasting state.

Thromboembolic Disease – Critical Evaluation of Laboratory Investigation

Previous studies of patients with thromboembolic disease have revealed an association either with hereditary anticoagulant protein deficiencies or with defects in the fibrinolytic system. To obtain a more comprehensive picture and to investigate which analyses are useful in the evaluation of such patients, we have performed an extensive laboratory investigation in 439 individuals with thromboembolic disease. Anticoagulant protein deficiencies were found in 24 patients. Deficiencies of protein C (n = 10) and protein S (n = 9) were most common followed by deficiencies of antithrombin III (n = 3) and plasminogen (n = 2). Six of the nine protein S deficient patients demonstrated a selective deficiency of free protein S with normal total protein S concentrations. To diagnose protein C and S deficiencies among the 201 patients receiving oral vitamin K antagonists, the concentrations of protein C and S were compared with the mean concentration of several other vitamin K-dependent proteins. One protein C and three protein S deficiencies were identified among the treated patients. The number of protein C deficiencies found in this group was significantly lower than the number found among untreated patients. Although fewer protein S deficiencies were also identified among the treated patients, than in the untreated group, the difference was not statistically significant. The results suggest that protein C deficiencies went undetected in the treated group and that oral anticoagulant therapy should be discontinued before efforts to diagnose protein C deficiency are made. We found no cases with heparin cofactor II deficiency. Lupus anticoagulant was present in 10 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A rapid and strong increase of plasminogen activator induced by experimental anaphylaxis in rabbits.

Anaphylactic shock was induced in rabbits by injecting bovine serum albumin (BSA) as an antigen. Measurements of the enzyme activities in the fibrinolytic system confirmed that a rapid and strong increase of plasminogen activator (PA) was induced during anaphylaxis. The euglobulin fibrinolytic activity (EFA) as estimated by the plasminogen-rich fibrin plate method rose significantly, peaking at 15 min after the BSA injection (when the arterial pressure was minimum). However, EFA was not detected by the plasminogen-poor fibrin plate method. The tissue-type PA (t-PA) activity using the natural substrate plasminogen increased significantly with a peak at 15 min. The amidolytic activity also simultaneously increased significantly using the t-PA substrate, H-D-Ile-Pro-Arg-pNA. The plasminogen activator inhibitor (PAI) activity remained at baseline levels until 30 min, but rose fourfold at 90 min. The main plasma fibrinolytic enzyme which increased in anaphylaxis was proved by zymography to be t-PA with a molecular weight (MW) of 69,000.

Euglobulin fibrinolytic activity in NIDDM patients

The euglobulin fibrinolytic activity was measured in 56 non-insulin-dependent diabetics and 118 age-matched healthy controls before and after venous occlusion for 5 min at 100 mmHg of the left antecubital vein. In the basal state, fibrinolytic activity was impaired in diabetics compared with controls (93.1 ± 6.7 vs 101.6 ± 0.9 BAU) ( P<0.05) and plasma fibrinogen level was increased but this did not reach statistical significance (467.3 ± 264.1 vs 359.2 ± 200.2 mg/dl). In diabetics, stimulated fibrinolysis following venous occlusion was depressed compared with controls (110.6 ± 3.9 vs 121.6 ± 1.9 BAU) ( P < 0.05). No relation of fibrinolytic activity to age, duration of diabetes, obesity, serum triglyceride, HbA 1c, or 24 h proteinuria was demonstrated. In the diabetic retinopathy group, the fibrinolytic activity was lower than in the non-retinopathy group. Diabetics with long-standing diabetes (10 years or more) who remained free from retinopathy had significantly increased fibrinolytic activity than the diabetics with short-standing diabetes (less than 10 years) who have developed retinopathy ( P<0.05). These findings imply a poor fibrinolytic activity, not in all diabetics, but only in those with retinopathy, and this may play a role in the development of diabetic retinopathy.

A lifelong bleeding disorder associated with a deficiency of plasminogen activator inhibitor type 1

A 36-year-old patient was investigated for a lifelong history of epistaxis and delayed bleeding after minor surgeries. Deficiencies or abnormalities of the coagulation system, of platelet function, or of factor XIII and alpha-2-antiplasmin were excluded. Consistently, however, over a period of 7 years, a high basal euglobulin fibrinolytic activity was observed that was characterized by a high tissue-type plasminogen activator (t-PA) activity, normal t-PA antigen, and undetectable plasminogen activator inhibitor type-1 (PAI-1) antigen and activity. The high specific activity of t-PA (640,000 IU/mg) and the minimal amounts of t-PA/PAI-1 complexes detected by fibrin zymography suggest that in this patient all t-PA was active. This is in striking contrast to normal plasma, where the majority of t-PA is complexed to PAI-1. Thus, in this patient, a severe deficiency of PAI-1 is associated with a delayed type bleeding tendency. Our observation underscores the importance of plasma PAI-1 for the stabilization of the hemostatic plug.

A Lifelong Bleeding Disorder Associated With a Deficiency of Plasminogen Activator Inhibitor Type 1

A 36-year-old patient was investigated for a lifelong history of epistaxis and delayed bleeding after minor surgeries. Deficiencies or abnormalities of the coagulation system, of platelet function, or of factor XIII and alpha-2-antiplasmin were excluded. Consistently, however, over a period of 7 years, a high basal euglobulin fibrinolytic activity was observed that was characterized by a high tissue-type plasminogen activator (t-PA) activity, normal t-PA antigen, and undetectable plasminogen activator inhibitor type-1 (PAI-1) antigen and activity. The high specific activity of t-PA (640,000 IU/mg) and the minimal amounts of t-PA/PAI-1 complexes detected by fibrin zymography suggest that in this patient all t-PA was active. This is in striking contrast to normal plasma, where the majority of t-PA is complexed to PAI-1. Thus, in this patient, a severe deficiency of PAI-1 is associated with a delayed type bleeding tendency. Our observation underscores the importance of plasma PAI-1 for the stabilization of the hemostatic plug.

Intra- and Postoperative Fibrinolysis in Patients Undergoing Cardiopulmonary Bypass Surgery

The influence of cardiopulmonary bypass (CPB) on fibrinolytic activity was assessed in 100 patients with valvular heart disease or atrial septal defects. Euglobulin fibrinolytic activity (EFA), tissue type plasminogen activator (t-PA) activity, plasminogen activator inhibitor 1 (PAI-1) activity, plasminogen, alpha 2-antiplasmin (alpha 2-AP), fibrinogen degradation products (FDP), and D-dimer were measured pre-, intra-, and postoperatively. There were significant increases in EFA and t-PA activity (p less than 0.002), and decreases in plasminogen and alpha 2-AP (p less than 0.0001) intraoperatively with respect to baseline values. t-PA activity decreased significantly after surgery (p less than 0.002), whereas PAI-1 activity showed a marked increase shortly after operation and on postoperative day 1 (p less than 0.0001). FDP and D-dimer levels were significantly increased both intra- and postoperatively, the latter showing higher values (p less than 0.01 and p less than 0.0001, respectively). This study shows that there is an activation of the fibrinolytic system, as a result of the increased activation of plasminogen and decreased levels of plasmin inhibitors, during CPB surgery followed by a postoperative fibrinolytic shutdown.

Coagulation and Fibrinolysis in Orthotopic Liver Transplantation: Role of the Recipient’s Disease and Use of Antithrombin III Concentrates

In this study we report the data obtained from extensive haemostatic testing of 25 patients undergoing orthotopic liver transplantation and the results of an open randomized pilot trial of antithrombin III concentrate administration during surgery. Marked differences in transfusional needs and in pre- and intraoperative blood coagulation and fibrinolytic changes were observed between recipients with liver cirrhosis and those with primary biliary cirrhosis. In the former, the increases in tissue-type plasminogen activator activity, total euglobulin fibrinolytic activity, and fibrin-derived degradation products occurred earlier and were more marked, as were the signs of increased thrombin formation. Supplementation of antithrombin III concentrate during surgery failed to induce significant changes in the main parameters studied and in the transfusional needs.

T-PA, u-PA and total euglobulin fibrinolytic activity during orthotopic liver transplantation

t-PA, u-PA and total euglobulin fibrinolytic activity during orthotopic liver transplantation

Increased Plasma Tissue-Type Plasminogen Activator Levels in Patients with Chronic Thrombocytopenia

Plasma fibrinolytic factors were measured in 14 patients with chronic idiopathic thrombocytopenic purpura (ITP), in 5 patients with chronic central thrombocytopenia and in 16 healthy volunteers. The von Willebrand factor (vWF), tissue-type plasminogen activator (t-PA) and D-dimer (DD) antigens were found to be significantly higher in both patient groups than in the control group. No difference appeared in euglobulin fibrinolytic activity and plasminogen activator inhibitor activity. The increases in both t-PA and vWF suggest the occurrence of an endothelial cell stimulation, associated with the reduction of circulating platelet number. The correlation of increased DD and t-PA levels during ITP can be the proof of a fibrinolysis activation and suggest an antifibrinolytic role of platelets at physiological concentrations. These results can justify antifibrinolytic therapy in bleeding thrombocytopenic patients.

Acute effects of retinoids on fibrinolysis before and after venous occlusion in healthy humans

The effects of acitretin and etretinate on the fibrinolytic system have been investigated in a double-blind, placebo-controlled cross-over study in twelve healthy volunteers. Euglobulin fibrinolytic activity, euglobulin clotlysis time, tissue-type plasminogen activator (t-PA) activity and antigen concentration in plasma were measured before and after 10 min of venous occlusion (VO), three hours after ingestion of the compounds. The plasminogen activator inhibitor (PAI) activity was also measured in each session before fibrinolysis stimulation. None of the parameters studied was significantly affected by the two retinoids in comparison with placebo. Our study demonstrates that a single oral dose of 100 mg of etretinate or acitretin, investigated 3 hours after drug administration does not significantly influence the fibrinolytic system in vivo in humans. This observation does not exclude an effect of retinoids after prolonged intake.

Tissue-type plasminogen activator antigen and plasminogen activator inhibitor in diabetes mellitus.

Parameters of fibrinolysis, including euglobulin fibrinolytic activity, tissue-type plasminogen activator (t-PA) antigen, plasminogen activator inhibitor (PA-inhibitor) activity, and plasmin-alpha 2-antiplasmin complex (PAP) were studied in 62 patients (35 women and 27 men; ages 53 +/- 16 years) with either insulin-dependent (IDDM) or noninsulin-dependent (NIDDM) diabetes mellitus. Compared to a control group of similar age (n = 57), the diabetic patients had a significantly lower mean euglobulin fibrinolytic activity (1.2 +/- 0.7 vs. 1.7 +/- 1.1 ng/ml, p less than 0.01) but significantly higher mean t-PA antigen (15.7 +/- 8.4 vs. 6.6 +/- 2.9 ng/ml, p less than 0.001) and PA-inhibitor activity (2.6 +/- 1.3 vs. 1.5 +/- 0.7 IU/ml, p less than 0.001) levels. Significant univariate correlations were observed between PA-inhibitor activity and age (r = 0.32, p less than 0.05), diastolic blood pressure (r = 0.42, p less than 0.01) and euglobulin fibrinolytic activity (r = -0.40, p less than 0.01). In multivariate analysis, only body mass index (positively) and euglobulin fibrinolytic activity (negatively) remained significantly related to PA-inhibitor activity in the total diabetic population as well as in the NIDDM group. The only parameter in the IDDM group significantly related to PA-inhibitor activity was diastolic blood pressure. These results suggest that PA-inhibitor plays a role in the regulation of fibrinolysis in diabetes patients and that factors like obesity and hypertension may be related to reduced fibrinolysis via PA-inhibitor levels.

Treatment of deep vein thrombosis with a very low molecular weight heparin (CY 222 - Choay): Thrombolysis and plasma fibrinolytic parameters

Thirty patients with deep venous thrombosis (DVT) (less than 7 days) were randomised into three treatment groups and received Choay's CY222 at the respective doses of 4 mg (group I), 3 mg (group II) and 2 mg/kg/24 h (group III) administered in three subcutaneous injections. A relationship between the thrombolytic effect evaluated on phlebography and plasma fibrinolysis parameters was looked for. Phlebography was performed before (D0) and on Day 7 (D7) of treatment and scored by Marder's index (MI). The mean decrease in MI on D7 was 40%. Blood samples were taken at DO and at 8.00 am before injection on D1, D3, D5 and D7. The following fibrinolysis parameters: euglobulin fibrinolytic activity (EFA), t-PA-Ag, PA inhibitor (PAI), showed no change during treatment in each group. Among patients with MI > 10 on DO (n=24) two response groups, A and B, were distinguished, based upon the thrombolytic response: Group A — six patients (three in treatment group I, two in group II and one in group III) with high degree of thrombolysis (decrease in MI ⩾ 80%); Group B — nine patients (three in each treatment group) with no thrombolytic response (decrease in MI ⩽ 20%). Changes in plasma fibrinolysis parameters in Groups A and B showed no difference during treatment. On DO mean PAI was lower in Group A than in Group B (p < 0.05). The difference persisted throughout treatment. All the patients with high PAI (> 4 U/ml) (5 of 30) before and during treatment were in Group B. These results show that CY222 is effective in the treatment of DVT. Its mechanism of action remains unclear, as no direct effect on EFA, t-PA-Ag, and PAI level could be demonstrated. No thrombolysis occured in patients with high PAI before treatment. Thus pre-treatment determination of PAI could have a predictive value in the efficacy of CY222 treatment.

Plasminogen activator inhibitor induced by lipopolysaccharide injection in the rat Zymographic analysis

It has been shown that endotoxin injection induces formation of Plasminogen Activator Inhibitor (PAI). The present study shows that a decrease in euglobulin fibrinolytic activity 4 h after lipopolysaccharide (LPS) injection is associated with an increase in urokinase neutralisation, either by euglobulin or plasma. After 30 μg/kg LPS this inhibitor reaches 6 U/ml in euglobulin and 41 U/ml in plasma. Zymographic analysis of post LPS euglobulin shows evidence of an increased PAI resulting in a reduction of tissue plasminogen activator (tPA) ( M r 68 000) and formation of higher complexes ( M r, 105 000), but development time is critical for detecting these modifications simultaneously. Increase in a urokinase binding factor in post-LPS plasma or euglobulin is clearly demonstrated from reduction in urokinase lytic bands ( M r, 34 000 and 54 000) with a parallel generation of a large complex ( M r 80 000 to 105 000). From this shift, the mol. weight of PAI may be estimated to be 46 000–51000. Combination of Polymyxin B or Colimycin with LPS could prevent the decrease in euglobulin fibrinolytic activity in low endotoxemia.

Metformin Decreases the High Plasminogen Activator Inhibition Capacity, Plasma Insulin and Triglyceride Levels in Non-Diabetic Obese Subjects

We have previously observed a positive correlation between Plasminogen Activator Inhibition capacity (PA Inhibition), Body Mass Index (BMI) and plasma insulin levels in a population of non diabetic subjects. The anti diabetic biguanide Metformin which decreases insulin resistance has been reported to increase the blood fibrinolytic activity. Therefore we have studied the effect of Metformin on PA Inhibition levels in obese subjects with normal glucose tolerance. Eighteen obese women (O) (BMI: 31.4 +/- 1.13, m +/- S.E.M.) were compared to age matched controls (C) (BMI: 20.2 +/- 0.8) and randomized to a 15 days treatment by Metformin (M) (1.7 g/day) or placebo (P) in a double blind study while on a weight maintaining diet. O compared to C had higher levels (m +/- S.E.M.) of PA Inhibition (9 +/- 1.8 IU/ml, versus 2.88 +/- 0.29 p less than 0.01), lower euglobulin fibrinolytic activity (EFA) (4.95 +/- 1.17 mm versus 9 +/- 0.29 p less than 0.05), higher plasma insulin (24.1 +/- 2.1. uU/ml), versus 12 +/- 1 p less than 0.01) and triglyceride (1.32 +/- 0.16 mmol/l, versus 0.8 +/- 0.08 p less than 0.05). After 15 days of treatment, in group M a significant decrease in PA Inhibition (5.51 +/- 1.4, versus 9.48 +/- 2.1 p less than 0.05) in plasma insulin (18.5 +/- 0.1, versus 24.5 +/- 3.5, p less than 0.05) and plasma triglyceride (1.08 +/- 0.1, versus 1.47 +/- 0.3 p less than 0.05) and an increase in EFA (6.50 +/- 0.28, versus 5.25 +/- 0.35 p less than 0.05) were observed. No significant variation was observed in group P.

A Selective Depression of Tissue Plasminogen Activator (t-PA) Activity in Euglobulins Characterises a Risk Group Among Survivors of Acute Myocardial Infarction

Among 29 patients recovering from a first-time acute myocardial infarction (AMI) 9 patients suffered reinfarction during a four year follow-up period. The 9 reinfarction patients were found to belong to a subgroup of 17 patients with a selective depression to near zero of euglobulin t-PA activity. None of the group of 12 patients with marked t-PA activity suffered a relapse. Euglobulin fibrinolytic activity as usually assayed did not distinguish between groups with or without relapse.

Deficient t-PA Release and Elevated PA Inhibitor Levels in Patients with Spontaneous or Recurrent Deep Venous Thrombosis

The fibrinolytic system was investigated in 120 patients with spontaneous or recurrent deep vein thrombosis (DVT) without any known organic disease able to explain by itself the occurrence of a thrombosis and without any known defect of antithrombin III, Heparin Cofactor II, Protein C, or Protein S. The assays included: Euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator related antigen (t-PA-Ag) and plasminogen activator inhibitor activity (PA inhibitor), which were measured before and after 10 min of venous occlusion (V.O.). On the basis of the results, the patients could be classified in 3 groups: good responders with an at least two-fold increase of EFA after venous occlusion (n = 76), poor responders with a lesser increase of EFA due to deficient release of t-PA (n = 12), and poor responders with a normal t-PA release but an increased level of PA-Inhibitor (n = 32). The poor responders due to deficient t-PA release (10% of total) had a higher incidence of recurrence of deep vein thrombosis, than the other groups (p less than 0.01). An overall correlation was found between the level of PA-Inhibitor activity and the triglyceride level (r = 0.40, p less than 0.01), suggesting that these elevations may be due to a common cause, at least in some of the patients. It is concluded that a poor fibrinolytic response to venous occlusion occurs in 35 percent of DVT patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of coagulation and fibrinolysis during intravenous infusion of recombinant human tissue-type plasminogen activator in patients with acute myocardial infarction.

Coagulation and fibrinolysis were studied in patients with acute myocardial infarction during intravenous infusion of recombinant human tissue-type plasminogen activator (rt-PA) (0.75 mg/kg over 90 min, n = 101), streptokinase (1,500,000 IU over 60 min, n = 61), or placebo (n = 40). In the rt-PA group, the plasma level of rt-PA antigen was 1.2 +/- 0.6 micrograms/ml (mean +/- SD) and the euglobulin fibrinolytic activity (EFA) was 910 +/- 735 IU t-PA/ml. In the streptokinase group, the EFA was equivalent to 430 +/- 435 IU t-PA/ml. At the end of the infusion, the plasma fibrinogen level measured with a coagulation rate assay was decreased to 57 +/- 33% of the preinfusion value in the rt-PA group, to 7 +/- 10% in the streptokinase group, and remained unchanged in the placebo group. Fibrinogen-fibrin degradation products increased to 0.75 +/- 0.54 mg/ml in the streptokinase group but to only 0.10 +/- 0.13 mg/ml in the rt-PA group. The plasma levels of alpha 2-antiplasmin, plasminogen, and factor V decreased to between 30% and 45% in the rt-PA group but significantly more in the streptokinase group (to between 15% and 25%). Thus rt-PA induced much less systemic fibrinolytic activation than streptokinase. In the patients who received rt-PA, a weak correlation (r = .21, n = 89, .1 greater than p greater than .05) was found between the extent of fibrinogen breakdown at 90 min and the plasma rt-PA concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between blood fibrinolytic activity, plasminogen activator inhibitor level, plasma insulin level, and relative body weight in normal and obese subjects

This study was undertaken to obtain further information on the mechanism by which blood fibrinolytic activity, a balance between plasminogen activators and inhibitors, is lowered in obese subjects. Fasting blood samples were collected from 35 subjects, aged 15 to 45 years, with normal glucose tolerance and a Body Mass Index (BMI) varying widely between 16 and 45 (normal, 19 to 25). Euglobulin Fibrinolytic Activity (EFA) did not correlate with the level of tissue type plasminogen activator (t-PA) related antigen but exhibited a negative correlation with the level of PA inhibitor ( r = −.609, P < 0.01). EFA was negatively and PA inhibitor positively correlated with both BMI ( r = −.381, P < 0.02 and .664, P < 0.01, respectively) and plasma insulin level ( r = .410, P < 0.02 and .521, P < 0.01, respectively). Stepwise analysis showed that these correlations were independent. As expected, plasma insulin was correlated with BMI ( r = .512, P < 0.01) and triglyceride level ( r = .38, P < 0.02), total cholesterol with age ( r = .379, P < 0.02). Ten obese subjects were submitted to a 24-hour fast. While body weight did not change appreciably, plasma insulin decreased from 22.3 ± 2.2 to 16.3 ± 1.1 μU/ml, EFA increased from 3.6 ± .8 to 4.9 ± .67 mm, and PA inhibitor decreased from 4.52 ± .76 to 3.44 ± .63 IU/mL. All these differences were significant. T-PA-related antigen did not change. These results suggest that PA inhibitor plays a major role in the regulation of fibrinolysis in healthy subjects and that high plasma insulin levels may be responsible for low fibrinolysis through high levels of PA inhibitor in obese subjects.