Sex-related differences in the associations between hyperleptinemia, insulin resistance and dysfibrinolysis

The adipocyte-derived hormone leptin is associated with insulin resistance and reduced fibrinolytic status--or dysfibrinolysis--in humans. As leptin associates differentially to the development of cardiovascular disease and diabetes in men and women, we hypothesized that leptin and insulin sensitivity are related to dysfibrinolysis in a sex-dependent manner. Thirty-two men and 40 women were recruited from the Monitoring of trends and determinants in Cardiovascular disease (MONICA) population sample, representing the highest and lowest quartiles of fasting insulin levels. Lipids, fibrinolytic status [plasminogen activator inhibitor 1 (PAI-1) activity, tissue plasminogen activator (tPA) mass and activity, and tPA-PAI complex], leptin, testosterone and sex-hormone-binding globulin were measured. Insulin sensitivity was estimated using the euglycaemic clamp technique. Body composition was determined by bioimpedance. Determinants for circulating levels of fibrinolytic factors were explored in a multivariate linear regression analysis. Levels of fibrinolytic variables and estimated insulin sensitivity did not differ between men and women. Leptin was independently associated with reduced fibrinolytic status (high PAI-1 activity, low tPA activity, high tPA mass, and high tPA-PAI complex) in men (P < 0.001-0.002). In women, fat mass and/or insulin sensitivity were related to these factors (P < 0.001-0.03), and leptin only to reduced tPA activity (P = 0.002). Hyperleptinemia, dysfibrinolysis, insulin sensitivity and androgenicity associate differentially in men and women.     

Relationship between plasma plasminogen activator inhibitor-1 activity and VLDL triglyceride concentration,insulin levels and insulin sensitivity: studies in randomly selected normo- and hypertriglyceridaemic men

Summary Impaired fibrinolytic function secondary to elevated plasma plasminogen activator inhibitor-1 activity, hypertriglyceridaemia and hyperinsulinaemia are frequent findings in patients with coronary heart disease. It has been debated whether VLDL or insulin is the major regulator of plasma plasminogen activator inhibitor-1 activity. This study examines the relationships between plasma plasminogen activator inhibitor-1 activity and VLDL triglyceride concentration, fasting and post-oral glucose load insulin levels and insulin sensitivity, as estimated by the minimal model method. Subjects studied were randomly selected hypertriglyceridaemic (n=65) and age-matched normotriglyceridaemic (n=61) men, aged 40–50 years, recruited in a population survey. Plasma plasminogen activator inhibitor-1 activity was higher in the hypertriglyceridaemic than in the normotriglyceridaemic group (21±14 vs 10±8 mU/l; p<0.01). The hypertriglyceridaemic group had higher serum insulin, basal as well as 2 h after intake of the oral glucose load, and a lower insulin sensitivity index. In univariate analysis, plasma plasminogen activator inhibitor-1 activity correlated positively with VLDL triglycerides in both the hyper- and normotriglyceridaemic groups (r=0.43 r=0.60, respectively) and negatively with the insulin sensitivity index (r=–0.35 r=–0.44, respectively). In multivariate analysis, VLDL triglyceride levels were found to be independently related to plasma plasminogen activator inhibitor-1 activity in both groups, whereas insulin sensitivity/serum insulin levels were not. An unexpected finding was that the serum activity of the enzyme gamma glutamyl transpeptidase appeared to influence the relationships for plasma plasminogen activator inhibitor-1 in the hypertriglyceridaemic group. In conclusion, this population-based study indicates that VLDL triglyceride concentration is one of the major determinants of plasma plasminogen activator inhibitor-1 activity in both normotriglyceridaemic and hypertriglyceridaemic men.     

Beneficial effect of a moderately energy-restricted diet on fibrinolytic factors in non-obese men

Impaired fibrinolytic activity has been reported in the elderly and is thought to play a role in the etiology of cardiovascular disease, one of the leading causes of death in most Western countries. Since restriction of energy intake has been demonstrated to act beneficially on the aging process in a variety of species, we studied the effect of a 10-week moderately energy-restricted (ER) regimen (80% of habitual) on plasminogen activator inhibitor (PAl) activity, PAl-1 antigen, tissue plasminogen activator (tPA) activity, and tPA antigen in non-obese, middle-aged men. Moreover, the relationship between these fibrinolytic markers and glucose tolerance was investigated. Weight loss in the ER group (n = 16) was considerable (−7.4 ± 1.7 kg, P < .001). Subjects in the control group (n = 8) also lost some weight (−2.1 ± 1.5 kg, P < .01). Fasting glucose levels decreased in the ER group (−0.31 ± 0.48 mmol/L, P < .05), which was correlated with the extent of weight loss (P < .01). Baseline insulin levels at 2 hours after an oral glucose load correlated with baseline PAl activity (P < .001) and PAl-1 antigen levels (P < .001). PAl activity decreased in the ER group (−2.94 ± 2.90 IU/mL, P < .001), particularly in subjects with a high baseline PAl activity (>9 IU/mL). Furthermore, energy restriction led to decreased PAl-1 antigen concentration (P < .05), a nonsignificant increase in tPA activity, and a decrease in tPA antigen concentration (P < .001). All these changes were more clear in subjects with a high baseline PAl activity: These results suggest that 10 weeks of moderate energy restriction has a profibrinolytic effect in non-obese, middle-aged men, at least in subjects with higher baseline PAl activity (>9 IU/mL). Moreover, in line with the suggestion that high PAl activity goes together with insulin resistance, a relationship between insulin concentration after a glucose load and PAl activity was found.     

Interrelationships between plasma levels of plasminogen activator inhibitor, tissue plasminogen activator, lipoprotein (a), and established cardiovascular risk factors in a north Swedish population

Serum lipids, lipoprotein (a), plasminogen activator inhibitor and tissue plasminogen activator levels were measured in 260 subjects, constituting a cross-section sample of 30-60-year-old men and women. For Lp(a), there were positive correlations with age and cholesterol, but not with any of other measured parameters. Triglyceride, cholesterol, and HDL-cholesterol (inversely) levels were associated with waist-to-hip girth circumference ratio: this variable remained significant in a multiple regression model. PAI-1 activity and tPA antigen levels were positively associated with triglycerides and inversely associated with HDL-cholesterol. Moreover, tPA antigen was positively related to total cholesterol level. In multiple regression analysis, however, only triglycerides were found to contribute significantly to the variance of tPA antigen and PAI-1 activity levels, when BMI (in men) and abdominal skinfold thickness (in women) were entered into the model. Insulin or glucose postload responses to an OGTT were not independently related to any lipid or fibrinolytic variable. These data demonstrate the importance of anthropometric variables both for fibrinolytic variables and traditional lipid risk factors. Only Lp(a) was found to be largely unrelated to the endocrine-metabolic and anthropometric variables.     

Age-related effects of regular physical activity on hemostatic factors in men

Background Age-related changes in blood coagulation and fibrinolytic factors are associated with an increase in risk of thrombotic events. The purpose of this study was to assess the effects of age, regular aerobic exercise and detraining on blood coagulation and fibrinolytic factors in men. Methods Initially, 41 sedentary and 42 physically active men (20–64 years) were analyzed for plasma levels of coagulation and fibrinolytic factors. Twelve sedentary men were then subjected to 16-week aerobic exercise training and subsequent 2-week detraining. Their blood samples taken at rest were assayed for activity levels of prothrombin, coagulation factor (F) V, VII, VIII, IX, X, XI and XIII, antithrombin III, protein C and plasminogen, and for antigen levels of fibrinogen, prothrombin fragment 1 + 2 (F1 + 2), FIX, protein C, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor 1 (PAI-1) and tPA/PAI-1 complex. Results Plasma levels of most coagulation factors, particularly for fibrinogen and FIX antigens as well as FXIII activity significantly increased with aging in sedentary men, while that tendency disappeared in physically active men. By the exercise training, plasma antigen and/or activity levels of most blood coagulation factors except for prothrombin and FIX decreased. These training-effects, however, disappeared after detraining, and in some cases even rebounded to higher levels than those of pre-training. Plasma antigen levels of tPA, PAI-1 and tPA/PAI-1 complex decreased with the training and remained low even after detraining. Conclusion Regular aerobic exercises give complex effects on expression of hemostatic factors, overall favoring the hemostatic balance to less thrombotic, partly cancelling out the age effects.     

The Relationship Between Plasminogen Activator Inhibitor-1 and Insulin Resistance in Newly Diagnosed Type 2 Diabetes Mellitus

It is not clear whether elevated levels of the fibrinolytic inhibitor, plasminogen activator inhibitor-1 (PAI-1) in Type 2 diabetes mellitus are the result of obesity or coexistent atherosclerosis. Therefore the relationship between PAI-1 and insulin resistance, determined by the homeostasis model assessment (HOMA) was investigated in a group of 26 insulin-resistant, normotensive newly diagnosed Type 2 diabetic patients with a low probability of atherosclerosis. Compared with a normal control group, closely matched for body mass index (BMI), fibrinolytic activity was depressed in the diabetic patients due to elevated levels of the inhibitor PAI-1, 17.6 (11.1–28) vs 8.4 (4.9–14.1) IU ml^?1, p < 0.001. PAI-1 was related to BMI, r = 0.59, p < 0.001 plasma insulin, r=0.66, p < 0.001; insulin resistance, r = 0.54, p< 0.005 and urinary albumin excretion, r=0.48, p < 0.01, but not HbA_1c or fasting glucose. PAI-1 was not related to blood pressure or plasma triglyceride levels. This study suggests that at the time of diagnosis of Type 2 diabetes mellitus, elevated PAI-1 levels are already linked to other risk factors for vascular disease including hyperinsulinaemia, insulin resistance, and urinary albumin excretion, and this is not the result of obesity or coexistent atherosclerosis.     

Plasma levels of tissue plasminogen activator/plasminogen activator inhibitor-1 complex and von Willebrand factor are significant risk markers for recurrent myocardial infarction in the Stockholm Heart Epidemiology Program (SHEEP) study

An impaired fibrinolytic function due to elevated plasma levels of plasminogen activator inhibitor (PAI)-1 activity or tissue plasminogen activator (tPA) antigen is correlated with the development of myocardial infarction (MI) in patients with manifest coronary heart disease. Recently, methods for determining the specific tPA/inhibitor complexes constituting tPA antigen in plasma have become available. In the Stockholm Heart Epidemiology Program (SHEEP) study, 86 of 1212 MI patients, subjected to blood sampling in a metabolically stable period, suffered reinfarction before the end of 1996. These individuals have been compared with an approximately equal number of matched MI patients without recurrence and a group of matched healthy control subjects regarding the plasma concentrations of some hemostatic factors. The hemostatic compounds studied (fibrinogen, von Willebrand factor, tPA antigen, PAI-1, and the tPA/PAI-1 complex) were typically higher in the groups (men and women) with recurrence of MI compared with those without. The plasma concentrations were also typically higher in the pooled groups of patients compared with the groups of healthy control subjects. The largest between-group differences were found for the plasma tPA/PAI-1 complex. The crude odds ratio for reinfarction associated with higher concentration (>/=75th percentile among the control subjects) of tPA/PAI-1 was 1.8 (95% CI 1.1 to 3.1); the corresponding crude odds ratio for von Willebrand factor was 2.3 (1. 3 to 4.0). The tPA/PAI-1 complex correlated strongly with PAI-1 and tPA antigen in all groups and with serum triglycerides and body mass index in all groups except for women with reinfarction. An increased plasma level of tPA/PAI-1 complex is a novel risk marker for recurrent MI in men and women. Most likely, increased plasma levels of tPA/PAI-1 complex reflect impaired fibrinolysis, because the correlation with PAI-1 is strong. Further support is obtained indicating that the plasma concentration of von Willebrand factor is also an important risk marker for recurrent MI.     

Relationship of Oxidative Stress and Fibrinolysis in Diabetes Mellitus

This study attempted to verify the existence of a relationship between oxidative stress documented by malondialdehyde (MDA) and superoxide dismutase (SOD) and fibrinolysis analysed by tissue plasminogen activator (tPA) and its inhibitor (PAI-1) in diabetes mellitus. Forty-seven patients with Type 1 (n = 27) and Type 2 (n = 20) diabetes were examined together with 20 non-diabetic controls. The following were analysed: plasma MDA concentration, SOD activity in erythrocytes, tPA activity and antigen, PAI-1 activity and antigen, fasting blood glucose, fructosamine, glycated haemoglobin (HbA_lc), and urine albumin. SOD activity was decreased in patients with diabetes. This contrasted with an increased plasma MDA concentration especially in Type 2 diabetes as compared with Type 1 or healthy persons (p < 0.001). tPA activity was increased in both groups of patients with diabetes as compared to healthy persons (p < 0.001), PAI-1 activity was higher in Type 2 diabetes with vascular changes than in the remaining subgroups (p < 0.001). Multivariate analysis revealed a significant positive relationship between plasma MDA concentrations and PAI-1 antigen (r = 0.53, p < 0.001) and a negative relationship between SOD and tPA activities (r = −0.53, p < 0.01). We conclude that oxidative stress may modulate fibrinolytic properties in diabetes mellitus.     

Impaired fibrinolysis and insulin resistance in patients with hypertension

Plasma plasminogen activator inhibitor type 1 (PAI-1) and tissue plasminogen activator (tPA) antigens and activities were measured in 28 patients with hypertension and 12 normal controls. Steady state plasma glucose (SSPG) concentrations were also determined after an infusion of somatostatin, insulin and glucose. Patients with hypertension were further subdivided into two groups: insulin resistance (SSPG > 190 mg/dL, n = 14) and no insulin resistance (SSPG < 190 mg/dL, n = 14). As compared to normal controls, hypertensive patients, either with or without insulin resistance, had significant (P < .005) increases in PAI-1 activity (18.6 ± 1.3 ν 8.1 ± 0.8 IU/mL), PAI-1 antigen (31.1 ± 2.0 ν 12.7 ± 0.9 ng/mL) and tPA antigen (15.5 ± 0.9 ν 8.8 ± 0.9 ng/mL), and significant decrease in tPA activity (0.43 ± 0.05 ν 1.02 ± 0.16 IU/mL) than normotensive controls. Furthermore, hypertensive patients with insulin resistance had significantly higher PAI-1 activity (22.0 ± 2.2 ν 15.3 ± 0.8 IU/mL, P = .006) and tPA antigen (17.4 ± 1.2 ν 13.6 ± 1.3 ng/mL, P = .02) than did hypertensive patients without insulin resistance. However, PAI-1 antigen was insignificantly higher (34.1 ± 2.9 ν 28.1 ± 2.4 ng/mL, P = .06) and tPA activity insignificantly lower (0.42 ± 0.08 ν 0.43 ± 0.08 IU/mL, P = .45) in hypertensive patients with insulin resistance than in those without insulin resistance. In addition, PAI-1 activity and tPA antigen were significantly correlated with blood pressure, SSPG, triglyceride, HDL-cholesterol and integrated glucose response to an oral load of 75 g glucose. Thus, patients with hypertension have impaired fibrinolytic activity due to increased PAI-1 when compared to normotensive controls, and the magnitude of this fibrinolytic defect is greater in hypertensive patients who have insulin resistance. Insulin resistance with associated metabolic abnormalities may be one of the causes for impaired fibrinolysis in hypertension.     

Abdominal obesity is associated with an impaired fibrinolytic activity and elevated plasminogen activator inhibitor-1

Recent epidemiologic studies have shown that abdominal obesity, characterized by a high waist to hip circumference ratio (WHR), is associated with increased cardiovascular morbidity and mortality. The present study examines components of the fibrinolytic system in obese and lean middle-aged women with a high and low WHR. Ten women in each group were carefully matched with respect to age, body weight, lean body mass, and body fat. Fibrinogen and endothelial type of plasminogen activator inhibitor -1 (PAI-1) were significantly elevated in the obese women with a high WHR compared with the obese women with a low WHR or with both groups of lean women. In addition, obese women with a high WHR exhibited a greater metabolic risk profile (elevated glucose, insulin, and triglyceride levels). When all subjects were pooled for the analyses, both fibrinogen and PAI-1 levels correlated positively with glucose and insulin levels. PAI-1 was also negatively related to degree of insulin sensitivity measured with the euglycemic clamp technique. In the obese groups, WHR but not body mass index (BMI), correlated with PAI-1 levels. No such correlations were seen in the lean groups. In conclusion, the data show that a high WHR in obese, but not lean middle-aged women, is associated with an impaired fibrinolytic activity. This perturbation becomes enhanced when it is associated with hyperinsulinemia and insulin resistance, which is a typical feature of abdominal obesity.     

The plasminogen activator system in young and lean women with polycystic ovary syndrome

The purpose of the study was to evaluate the plasminogen activator inhibitor-1 (PAI-1) levels and PAI-1 activity in young and lean women with PCOS and to compare with controls matched for age and weight. Thirty two women with PCOS and 25 weight and age-matched healthy controls participated in this study. Patients were evaluated clinically and by pelvic ultrasound and fasting blood samples were taken for hematological and biochemical tests. Fasting insulin, glucose, lipid profile, FSH, LH, PRL, testosterone, SHBG, 17-hydroxyprogesterone, androstenedione, PAI-1 antigen; PAI-1 activity, insulin sensitivity indices (HOMA and QUICKI) were measured. PAI-1 Ag and activity were significantly higher in PCOS women than healthy control group. PAI-1 levels were directly correlated with BMI, insulin levels and insulin sensitivity indices. PAI-1 activity was also correlated with insulin levels and insulin resistance. As a conclusion PAI-1 Ag levels and activity were increased in lean PCOS women and these were directly correlated with insulin resistance. The finding may contribute to evidence of increase risk of cardiovascular disease and anovulatory infertility in PCOS women.     

Glycaemic Control,Smoking Habits and Diabetes Duration Affect the Extrinsic Fibrinolytic System in Type I Diabetic Patients but Microangiopathy Does Not

ABSTRACT The fibrinolytic system was studied in 43 type I diabetic patients with long duration of the disease, with or without evidence of microangiopathy, and in 26 control subjects. There were positive and independent correlations between tissue plasminogen activator (tPA) activity after venous occlusion and HbA_lc, and between triglycerides and plasminogen activator inhibitor (PAI-1) and tPA antigen concentrations before and after venous occlusion. The tPA activities both at rest and after venous occlusion were higher in the patients. There were no differences with regard to sex, hypertension or nephropathy for the levels of fibrinolytic variables in these patients. Subjects with retinopathy did not differ from those without retinopathy. Diabetes duration showed a significant negative association with tPA activity in multivariate regression analysis. Tobacco-smoking diabetics, as compared to non-smoking, had an increased tPA antigen release at venous occlusion, but also higher PAI-1 levels and reduced specific activity of the tPA protein. When assessed with the new specific assays now available, the fibrinolytic parameters appear to be specific indicators of endothelial dysfunction related to smoking and to degree of glycaemic control in type I diabetic subjects.     

Normal plasminogen activator inhibitor levels at long-term follow-up after jejuno-ileal bypass surgery in morbidly obese individuals.

Forty-five patients who had been subjected to jejuno-ileal bypass (JIB) surgery for morbid obesity and 10 obese nonsurgery subjects were studied. The former group was examined 14 to 20 years after surgery, and was found to have lower mean plasminogen activator inhibitor type 1 (PAI-1) activity (8.4 v 32 U/mL, P < .001), tissue plasminogen activator (tPA) antigen concentrations (7.2 v 12 micrograms/L, P < .01), body mass index (BMI), and fasting plasma insulin, triglyceride, and cholesterol levels. The PAI-1 levels were correlated with BMI, waist to hip ratio, and insulin, triglyceride, and cholesterol levels. Thus, previously obese subjects have normal PAI levels 14 to 20 years after treatment with JIB surgery, in contrast to the high PAI-1 levels in nonsurgery obese subjects.     

Increased levels of tPA antigen and tPA/PAI-1 complex in myotonic dystrophy

Abstract. Johansson Å, Boman K, Cederquist K, Forsberg H, Olsson T (Umeå University Hospital, Umeå, Skellefteå County Hospital, Skellefteå, and Boden Hospital, Boden, Sweden). Increased levels of tPA antigen and tPA/PAI‐1 complex in myotonic dystrophy. J Intern Med 2001; 249 : 503–510. Objective. To assess the fibrinolytic system in myotonic dystrophy (DM1), a disease connected to features of the metabolic syndrome, including a prominent insulin resistance, increased body fat mass, and hypertriglyceridaemia. We hypothesized that abnormalities in the fibrinolytic system are linked to metabolic dysfunction in DM1. Design. Circulating morning levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI‐1) antigens, tPA/PAI‐1 complex, lipids and insulin were determined. Genetic analyses, including calculation of allele size, were performed in all patients. Body fat mass was estimated with bioelectrical impedance analysis. Setting. Out‐patient clinic in collaboration with Umeå University Hospital. Subjects. A total of 42 otherwise healthy patients with DM1 (22 men, 20 women; median age 41.5 years) and 50 controls (27 men, 23 women; median age 42.0 years). Main outcome measures. The tPA and PAI‐1 antigens, tPA/PAI‐1 complex, blood lipids and body fat mass. Results. The tPA antigen and tPA/PAI‐1 complex levels were significantly increased in DM1 patients (P < 0.001 and P < 0.05, respectively) whilst levels of PAI‐1 did not differ from controls. Triglyceride levels were increased (P < 0.001) whereas HDL cholesterol levels were lower in DM1 patients (P < 0.05). Body fat mass was increased in DM1 patients (P < 0.001). Conclusions. The fibrinolytic system is disturbed in DM1 patients, with increased levels of tPA and tPA/PAI‐1 complex but paradoxically unaltered levels of PAI‐1, in spite of a severely increased body fat mass. This may imply an abnormal function of adipose tissue in DM1, and calls for further studies of the fibrinolytic system in this disease.     

Hypofibrinolysis in patients with hypercoagulability: The roles of urokinase and of plasminogen activator inhibitor

The prevalence of abnormalities of fibrinolysis in patients with venous thromboembolism is as yet unknown. Defined abnormalities include congenital dysfunction and deficiency of plasminogen, and probably impaired plasminogen activation secondary to elevated levels of plasminogen activator inhibitor type 1 (PAI-1) or to impaired release of tissue plasminogen activator (tPA). In this preliminary study, we analyzed plasma samples from 21 patients for whom an investigation for possible thrombophilia was requested. Twenty of the patients had venous thromboembolism, and one had arterial thrombosis at an early age. Two patients had deficiency of protein C or protein S, but no other recognized biochemical disturbances related to thrombophilia were identified. Patient samples and plasma from 25 normal controls were assayed for tPA activity, PAI-1 activity, and urokinase (uPA) activity and antigen. tPA activity and antigen were not significantly different in patients than in controls. PAI-1 activity was significantly greater in patients (P < 0.0001). uPA activity was not different in the two groups. However, uPA antigen was significantly reduced in patients compared to controls (P = 0.001). These data suggest that hypofibrinolysis leading to a risk of thrombosis may be caused not only by elevated PAI-1 activity but also by reduced total uPA concentration. © 1993 Wiley-Liss, Inc.     

Hypo-fibrinolysis in patients with hypertension and elevated cholesterol

To test the hypothesis that increased blood pressure and hyperlipidaemia result in changes in the fibrinolytic system, 84 subjects with both hypertension and elevated serum cholesterol levels (the high risk group) were compared with 55 controls matched with respect to age, sex and body mass index (BMI). Plasminogen activator inhibitor (PAI-1), and tissue plasminogen activator (tPA) antigen and activity were measured before and after venous occlusion. In the high risk group, tPA activity was significantly lower both before and after venous occlusion and PAI-1 levels were significantly higher. In a multivariate analysis the triglyceride levels, diastolic blood pressure and cholesterol levels were independently associated with the PAI-1 levels. Diastolic blood pressure was independently and inversely associated with resting tPA activity. We conclude that patients with hypertension and hyperlipidaemia have a reduced activity of the fibrinolytic system, an effect which is unrelated to differences in age, sex, smoking or BMI.     

Activation of fibrinolysis and coagulation in non-occlusive intestinal ischaemia in a pig model.

The present study was carried out to explore the dynamics of the fibrinolytic and coagulation systems during non-occlusive intestinal ischaemia in a porcine model. Nineteen pigs underwent laparotomy. The inferior mesenteric artery and the collateral vessels to the rectum were ligated. The superior mesenteric artery (SMA) was isolated at its origin from the aorta, and constriction and flowmeter devices were applied. The blood flow of the SMA was reduced to cause ischaemia in the distal colon within the pHi interval 6.9-7.1. Fibrinogen, soluble fibrin, D-dimer, tissue plasminogen activator/plasminogen activator inhibitor-1 (tPA/PAI-1) complex and albumin were measured. Corrections for pig D-dimer and albumin were performed. Fibrinogen decreased significantly after laparotomy (P < 0.0001) and further after constriction of the SMA (P < 0.05), whereas soluble fibrin increased significantly (P < 0.005) after constriction of the SMA. The tPA/PAI-1 complex increased significantly after laparotomy (P < 0.05) and, after constriction of the SMA, the values first tended to decrease (P = 0.06) and then to increase (P = 0.056). The need to calibrate assays of human plasma proteins when applying them to experimental pig models was demonstrated. After constriction of the SMA, there was a rapidly reversed peak in the coagulation marker soluble fibrin and a strong tendency of alteration of the fibrinolytic marker tPA/PAI-1 complex.     

Relationship of glucose concentrations with PAI-1 and t-PA in subjects with normal glucose tolerance.

AIM: To study metabolic risk factors for the development of cardiovascular disease (CVD), including markers of the fibrinolytic system in relation to blood glucose levels in subjects with normal glucose tolerance and fasting blood glucose levels below 5.6 mmol/l. METHODS: Cross-sectional, community-based study from a primary health-care centre of adult subjects with normal glucose tolerance. Analysis of fasting and 2-h post-load blood glucose concentrations were centralized and related to anthropometric characteristics, metabolic variables, inflammatory markers, and coagulation and fibrinolytic variables. RESULTS: Increasing fasting blood glucose concentrations within the normal range in subjects with normal glucose tolerance were associated with increasing age, body mass index, and waist circumference, and with increasing concentrations of metabolic risk factors for development of CVD. After adjustment for gender, age, body mass index (BMI), and fasting insulin, levels of plasmin activator inhibitor (PAI-1) and tissue type plasminogen activator (t-PA) increased significantly with increasing levels of fasting glucose within the normal range (P = 0.012 and P < 0.0001, respectively). CONCLUSIONS: We found risk factors for CVD, specifically key components of the fibrinolytic system, PAI-1 and t-PA, increased with increasing fasting glucose levels even in subjects with normal glucose tolerance. This observation may help to explain the increased risk of CVD with increasing values of fasting glucose in the normal range.     

Low level of tissue plasminogen activator activity in non-diabetic patients with a first myocardial infarction

OBJECTIVE: To explore the role of tissue plasminogen activator (tPA) activity and plasminogen activator inhibitor type 1 (PAI-1) in survivors of a first myocardial infarction (MI). Insulin and proinsulin were analysed as potential risk factors. DESIGN: Case-control study in northern Sweden. SUBJECTS: A total of 115 patients under 65 years of age with a first MI were enrolled and recalled for further examination 3 months later. Twenty-seven patients were excluded, 17 with known diabetes and 10 who did not come to the follow-up, giving a final number of 88 patients, 73 men and 15 women. Patients were age- and sex-matched with control subjects drawn from the local cohort in the MONICA population survey 1994. MAIN OUTCOME MEASURES: We compared MI patients and controls using univariate and multiple regression analyses including odds ratios (OR). RESULTS: PAI-1 activity, fibrinogen, postload insulin and -proinsulin were significantly higher and tPA activity significantly lower in MI patients in the univariate analysis. In a multiple regression analysis, including also age, sex and cardiovascular risk factors, these parameters were divided in quartiles. The lowest quartile of tPA activity was significantly associated with MI (OR = 19.1; CI 3.0-123) together with the highest quartiles of fibrinogen (OR = 25; CI 5.2-120) but other variables were not. CONCLUSION: Low tPA activity, i.e. low fibrinolytic activity, characterized nondiabetic subjects after a first MI which is not explained by concomitant disturbances in metabolic and anthropometric variables.