tPA Antigen Research Articles

Impact of simvastatin on hemostatic and fibrinolytic regulators in Type 2 diabetes mellitus

Simvastatin, a widely used 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitor, effectively reduced cardiac death and ischemic events in patients with coronary heart disease (CHD) and diabetes mellitus (DM). The mechanism of cardiovascular benefits of statins in DM remains unclear. We examined how simvastatin influences the levels of several in vivo markers for coagulation and fibrinolysis in 26 Type 2 DM patients. The diabetic patients received 20 mg/day of simvastatin up to 12 months. The levels of total cholesterol (TC), low density lipoprotein–cholesterol (LDL-c) and triglycerides in peripheral circulation of patients were significantly reduced after ≥6 weeks of simvastatin treatment. Levels of prothrombin fragment 1 + 2 (F1 + 2), factor VII, plasminogen activator inhibitor-1 (PAI-1) and tissue factor pathway inhibitor (TFPI) antigens, but not tissue plasminogen activator (tPA) antigen, in the pre-simvastatin plasmas of the diabetic patients were significantly higher than the levels found in plasmas of healthy subjects. Significant reductions in F1 + 2 and PAI-1 levels were evident ≥6 weeks after the diabetic patients received simvastatin. Levels of total tPA, TFPI, FVII, hemoglobin A1c, fasting blood glucose, and insulin in the diabetic patients’ plasma were not significantly altered by simvastatin treatment. Positive correlations were found between PAI-1 versus TC, PAI-1 versus LDL-c, and FVII versus triglycerides in the plasmas of simvastatin-treated patients. The results suggest that simvastatin reduces in vivo prothrombinase activity and PAI-1 levels in type 2 DM patients. These actions may contribute to the protective properties of simvastatin against ischemic events in diabetic patients.

Tissue plasminogen activator antigen is strongly associated with myocardial infarction in young women

Women who develop acute myocardial infarction (AMI) at a young age have fewer classical risk factors and less coronary stenosis than older women. In this rare population, it is plausible that a heightened hemostatic system may play an important mechanistic role in thrombus formation and in the development of AMI. We chose to investigate whether or not there is an association between premature AMI and the plasma concentrations of five hemostatic measurements that had been previously established as risk factors for AMI, and of the inflammation marker C-reactive protein (CRP). Women who had survived AMI at the age of 45 years or less (n = 141) were drawn from those admitted to 125 Italian coronary care units over a 3-year period. In them, and in an equal number of controls, plasma levels of immunoreactive tissue plasminogen activator (tPA), plasminogen activation inhibitor 1 (PAI-1), von Willebrand factor (VWF), fibrinogen, D-dimer and CRP were measured. Higher levels of VWF, fibrinogen, CRP and tPA were associated with AMI. After adjustment for both classical and hemostatic risk factors, only tPA maintained an independent association with AMI: the odds ratios (taken as an index of relative risk) for tPA values in the middle and higher tertiles were 2.86 (CI 1.63-5.02) and 8.18 (CI 2.66-25.20), respectively. In conclusion, there is a strong association between non-fatal AMI and increased plasma levels of tPA antigen. This finding is thought to be the expression of a reduced rather than enhanced fibrinolytic activity.

Effects of Cilnidipine on Fibrinolysis in Chinese Hypertensive Patients

Hypertension is an important risk factor for myocardial infarction and stroke. Accumulating data support the association of blood pressure and impairment of fibrinolysis in hypertensive patients. Fibrinolysis plays a pivotal role in atherogenesis, but there are few studies that focus on evaluating the effect of calcium channel antagonists on fibrinolysis in hypertensive patients, and the results are controversial. The aim of this study was therefore to investigate the effects of cilnidipine on fibrinolysis in Chinese hypertensive patients. This study was an open-label, paired trial that included 43 patients with mild-to-moderate hypertension. After a 2-week placebo washout period, patients were treated with cilnidipine 5mg daily for 8 weeks. Venous blood was taken before and after treatment between 8am and 9am, after an overnight fast. Plasma tissue plasminogen activator (tPA) antigen and plasminogen activator inhibitor type 1 (PAI-1) antigen were measured by ELISA and plasma angiotensin II was measured by radioimmunoassay. After treatment with cilnidipine for 8 weeks, plasma tPA antigen level increased significantly (from 12.12 +/- 6.77 ng/mL pre-treatment to 16.12 +/- 11.89 ng/mL post-treatment, p < 0.05), and the PAI-1 antigen level remained unaffected. There were no significant changes in plasma angiotensin II. Systolic and diastolic blood pressures were significantly decreased without changes in heart rate. These data suggest that in hypertensive patients, a population with impaired fibrinolysis, cilnidipine may improve the fibrinolytic balance, and that cilnidipine is effective in treating hypertension without causing reflex tachycardia.

The effects of short-term raloxifene therapy on fibrinolysis markers: TAFI, tPA, and PAI-1

Background. Markers of fibrinolysis, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue-type plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) levels were studied for the evaluation of short-term effects of raloxifene administration in postmenopausal women. Methods. Thirty-nine postmenopausal women with osteopenia or osteoporosis were included in this prospective, controlled clinical study. Twenty-five women were given raloxifene hydrochloride (60 mg/day) plus calcium (500 mg/day). Age-matched controls (n = 14) were given only calcium. Plasma TAFI, tPA, and PAI-1 antigen levels were measured at baseline and after 3 months of treatment by commercially available ELISA kits. Variations of individuals were assessed by Wilcoxon's test. Relationship between those markers and demographic characteristics were investigated. Results. Three months of raloxifene treatment was associated with a significant decrease in the plasma TAFI antigen concentrations (16% change, P < 0.01), and a significant increase in tPA antigen concentrations (25% change, P < 0·05). A significant correlation was found between baseline TAFI antigen concentrations and the duration of amenorrhea (P < 0·05; r = 0·33). Conclusion. We suggest that the increased risk of venous thromboembolism due to raloxifene treatment may be related to increased tPA levels, but not TAFI levels.

Brachial Artery Flow-Mediated Vasodilation Is Correlated with Coronary Vasomotor and Fibrinolytic Responses Induced by Bradykinin

Endothelium plays a key role in the regulation of not only vascular tone but also thrombosis and fibrinolysis. Brachial flow-mediated vasodilation (FMD) provides a noninvasive method of assessing coronary endothelial dysfunction. However, no data are available on the relationship between brachial FMD and coronary fibrinolytic activity. Thus, we examined the relationship between brachial FMD and coronary vasomotor and fibrinolytic function. Brachial FMD by reactive hyperemia was defined as a change in diameter relative to the baseline as measured using high-resolution ultrasound. Coronary blood flow (CBF) responses to bradykinin (BK) were analyzed using Doppler flow velocity measurement. Coronary release of tissue-type plasminogen activator (tPA) antigen was determined as the transcardiac tPA gradient x [CBF x (100 - hematocrity 100)]. In 77 patients with normal coronary arteries, BK caused dose-dependent increases in CBF, transcardiac tPA gradient, and coronary tPA release. Among them, brachial FMD, the BK-induced CBF increase, and the coronary tPA release induced by BK in 14 diabetic subjects were lower than those in 63 non-diabetic subjects (p < 0.05, respectively). Brachial FMD correlated with the CBF increase, transcardiac tPA gradient (0.2 microg/min: r = 0.25; 0.6 microg/min: r = 0.43; 2.0 microg/min: r = 0.34; p < 0.05, respectively), and coronary tPA release (0.2 microg/min: r = 0.24; 0.6 microg/min: r = 0.44; 2.0 microg/min: r = 0.32; p < 0.05, respectively) in response to BK. Brachial FMD correlated significantly with coronary endothelial function and fibrinolytic activity in response to BK. Type 2 diabetes impaired coronary and brachial endothelium-dependent vasodilation and coronary fibrinolytic activity.

Relationship of physical fitness, hormone replacement therapy, and hemostatic risk factors in postmenopausal women

This cross-sectional study evaluated the relationship of physical fitness, hormone replacement therapy (HRT), and hemostatic profiles at rest and after an acute bout of maximal exercise in 48 healthy postmenopausal women. Subjects were categorized by fitness and HRT user status into four groups: unfit nonusers, fit nonusers, unfit users, and fit users. Fibrinolytic variables tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) activity, and antigen and prothrombin fragment 1 + 2, a molecular marker of in vivo thrombin generation, were measured before and after maximal exercise. Fibrinogen was also measured at rest. Higher tPA and lower PAI-1 activities (P <0.05) were seen in HRT users and fit groups. tPA and PAI-1 antigens were lower in HRT and fit groups (P <0.05) but not after correction for body mass index. Prothrombin fragment 1 + 2 was lower in the fit groups regardless of HRT status (P <0.05). Fibrinogen was similar in all groups. Favorable hemostatic profiles were observed in physically fit compared with unfit women, especially in HRT nonusers. Thus fitness is more strongly related to these hemostatic risk factors compared with HRT since HRT did not affect these hemostatic variables in fit postmenopausal women.

Tissue plasminogen activator antigen and D-dimer as markers for atherothrombotic risk among healthy postmenopausal women.

Plasma markers of fibrinolytic function are associated with incident coronary events among several, but not all, prospective epidemiologic investigations of healthy individuals. Few studies have evaluated this relationship in women. In addition, although menopausal hormone therapy (HT) may alter markers of fibrinolytic function, the relevance of this effect for coronary risk assessment has not been studied. In a prospective, nested case-control study among 75 343 postmenopausal women without prior cardiovascular disease or cancer, we evaluated the relationships of elevated tissue plasminogen activator (tPA) antigen and D-dimer with subsequent first coronary heart disease events over a median period of 2.9 years. Baseline levels of both biomarkers were higher among 304 cases compared with 304 controls matched on age, smoking status, ethnicity, and length of follow-up; median values were 9.0 versus 7.4 ng/mL (P<0.001) for tPA antigen and 27.6 versus 23.4 ng/mL (P=0.001) for D-dimer. In matched-pairs analyses, the odds ratio in the highest versus lowest quartile of tPA antigen was 3.5 (95% CI, 2.1 to 5.8; P trend <0.001) and for D-dimer was 2.0 (95% CI, 1.2 to 3.2; P trend=0.005). After adjustment for lipid and nonlipid risk factors, including C-reactive protein, tPA antigen remained a significant predictor. Multivariable-adjusted associations for D-dimer, although attenuated, largely remained statistically significant. When stratified by HT, the relationship between tPA antigen and incident coronary heart disease was similar among nonusers, estrogen-only users, and current users of any HT. Elevated tPA antigen and, to a lesser extent, D-dimer are independently associated with incident coronary events among postmenopausal women. In analyses stratified by HT, tPA antigen remained a consistent marker of increased coronary risk.

Antibodies to tissue-type plasminogen activator (tPA) in patients with antiphospholipid syndrome: evidence of interaction between the antibodies and the catalytic domain of tPA in 2 patients

AbstractThe causes of thrombosis and pregnancy loss in antiphospholipid syndrome (APS) are still unknown, although several hypotheses have been proposed and hypofibrinolysis has been implicated. Anti–tissue-type plasminogen activator (tPA) antibodies may induce fibrinolytic defects and preliminary data indicate an association with thrombosis in APS. We measured plasma anti-tPA antibody levels in 91 consecutive patients with APS, 91 healthy controls, 40 patients with antiphospholipid antibodies without APS symptoms, and 23 patients with systemic lupus erythematosus (SLE) without antiphospholipid antibodies and APS symptoms. Patients with APS had anti-tPA antibody levels higher than controls (P = .0001), patients with SLE (P = .0001), and asymptomatic antiphospholipid patients (P = .05). A subgroup of 53 patients had plasma levels of tPA antigen higher (P = .0001) and tPA activity lower (P = .05) than controls, with an inverse correlation (r = –0.454; P = .003) between anti-tPA antibody levels and tPA activity and no correlation with tPA antigen. The 2 patients with the highest antibody levels had tPA activity below the normal range. Their antibodies were, respectively, IgG1 and IgG3; both recognized human tPA, recombinant tPA, and the catalytic domain of tPA, but not β2-glycoprotein I, prothrombin, or plasminogen. Our data indicate that anti-tPA antibodies specifically interacting with the catalytic domain of tPA can be found in patients with APS, representing a possible cause of hypofibrinolysis.

High prevalence of metabolic syndrome among young women with nonfatal myocardial infarction.

The aim of this study was to determine if the metabolic syndrome (MetS) or other risk factors might be common among young women with nonfatal myocardial infarction (MI). A matched case-control study using a structured interview and questionnaires, plus analysis of conventional and nonconventional risk factors for MI in serum or plasma was carried out at a teaching hospital. Subjects were 40 women with nonfatal MI at or before age 45 and an equal number of age-matched, ethnicity-matched, and smoking-matched female control subjects. Cases and control subjects were not significantly different with regard to serum or plasma levels of homocysteine, anticardiolipin antibodies, beta(2)-glycoprotein I, prothrombin, folate, vitamin B(12), high-sensitivity C-reactive protein (CPR), fibrinogen, amyloid A, plasminogen activator inhibitor type 1 (PAI-1), or tissue plasminogen activator (tPA) antigen levels. Compared with matched controls, cases had a higher rate of obesity (37% vs. 12%, p = 0.02), a higher proportion of fasting glucose >/=110 mg/dl (9% vs. 1%, p = 0.01), and higher overall insulin resistance (27% vs. 5%, p = 0.007). Type 2 diabetes tended to be more common in cases (17% vs. 5%, p = 0.10). Cases were also more likely to be hypertensive (35% vs. 12%, p = 0.04) and dyslipidemic (80% vs. 42%, p = <0.001) and to have higher triglyceride levels (110 +/- 13 mg/dl vs. 96 +/- 12, p = 0.02). Overall, after controlling for weight, cases were 4.7 times more likely to have three or more diagnostic criteria of the MetS than matched controls: chi-square = 7.2, OR = 4.7, 95% CI (1.3, 25.3), p = 0.008. Although this study may have been underpowered to recognize the contribution of other risk factors, we found that the dominant predictor of nonfatal MI in young women was the MetS. Screening young women with central obesity for other parameters of the MetS may help reduce the risk of MI at an early age.

Association between obesity and a prothrombotic state: the Framingham Offspring Study.

Although obesity is associated with increased cardiovascular risk, the mechanism has not been fully explained. Since thrombosis is a critical component of cardiovascular disease, we examined the relationship between obesity and hemostatic factors. We studied 3230 subjects (55% females, mean age 54 years) without a history of cardiovascular disease in cycle 5 of the Framingham Offspring Study. Obesity was assessed by body mass index and waist-to-hip ratio. Fasting blood samples were obtained for fibrinogen, plasminogen activator inhibitor (PAI-1) antigen, tissue plasminogen activator (tPA) antigen, factor VII antigen, von Willebrand factor (VWF), and plasma viscosity. Body mass index was directly associated with fibrinogen, factor VII, PAI-1 and tPA antigen in both men and women (p>0.001) and with VWF and viscosity in women. Similar associations were present between waist-to-hip ratio and the hemostatic factors. With minor exceptions for VWF and viscosity, all associations persisted after controlling for age, smoking, total and HDL cholesterol, triglycerides, glucose level, blood pressure, and use of antihypertensive medication. The association between increased body mass index and waist-to-hip ratio and prothrombotic factors and impaired fibrinolysis suggests that obesity is a risk factor whose effect is mediated in part by a prothrombotic state.

Erythrocyte sodium/lithium countertransport is associated with thrombotic and fibrinolytic factors in 58-year-old men.

The metabolic syndrome, in which insulin resistance is the core feature, is associated both with dysregulation of thrombosis/fibrinolysis and erythrocyte sodium/lithium countertransport (SLC). To investigate this further we designed a cross-sectional study to examine whether factors involved in coagulation- and fibrinolysis systems were associated with SLC independently of insulin resistance in 93 58-year-old men. SLC was in univariate analysis positively correlated with PAI-1 activity (r = 0.35, p <0.01), tPA antigen (r = 0.38, p <0.01), von Willebrand factor (r = 0.25, p <0.05), protein S (r = 0.26, p <0.05), and C (r = 0.30, p <0.01), and negatively associated with tPA activity(r = -0.28, p <0.01). Since these correlations could be influenced by the components of the metabolic syndrome itself, a separate analysis with adjustment for glucose infusion rate (GIR), plasma insulin, body fat, sagittal diameter of the abdomen (SD) and log serum triglyceride concentration (TG) was conducted. Then SLC was associated with tPA antigen independent of GIR, plasma insulin, body fat, SD and TG. SLC was also associated with protein C independent of GIR, insulin, body fat and SD but not TG. In conclusion, we found a relationship between SLC and the fibrinolytic system that was not related to the metabolic syndrome.

Which factors are related to the presence of atherosclerosis in rheumatoid arthritis?

Objective: An accelerated progression of atherosclerosis may contribute to the increased mortality due to cardiovascular disease reported in rheumatoid arthritis (RA). The aim of this study was to identify variables, related to disease onset as well as to disease progression, of importance for the presence of atherosclerosis, as diagnosed by B-mode ultrasonography, in patients with medium-term RA. The results are based on the co-analysis of retrospective data as well as cross-sectional data. The impact of RA per se on atherosclerosis was evaluated relative to age- and sex-matched controls. Methods: Thirty-nine RA patients, with a maximum age of 65 years, who had previously been included in a large retrospective cohort study, were assessed by duplex scanning after a disease duration of 19-23 years. In the present study, factors identified in the two earlier studies were assessed for their potential relationship with intima-media wall thickness (IMT) of the common carotid artery (CCA), and the presence and grade of atherosclerotic plaques of the CCA and the common femoral artery, in regression models. The candidate co-variates were: variables reflecting inflammatory activity at disease onset and at the time of ultrasound assessment, established cardiovascular risk factors, pharmacological treatment [corticosteroids, disease-modifying anti-rheumatic drugs (DMARDs)], and the presence of complications and co-morbidity identified during disease progression, as well as lipid levels, anti-lipid antibodies, haemostatic factors, and markers of immune activation measured at ultrasound assessment. Results: In patients with RA, analysis of simple linear regression models revealed those variables significantly associated with IMT-CCA to be age, tissue plasminogen activator (tPA) antigen, cholesterol, low density lipoprotein (LDL)-cholesterol, triglycerides, and atherosclerotic plaques while neither inflammatory status at disease onset, traditional cardiovascular risk factors, or pharmacological treatment during disease had any significant impact on IMT. In an estimated multiple linear regression model, variables associated with increasing log of IMT-CCA were the log of cholesterol and of soluble intracellular adhesion molecule 1 (sICAM-1), while methotrexate treatment tended to have a decreasing effect. In simple binary logistic regression, atherosclerotic plaques were associated with age, IMT-CCA, smoking, and the levels of sICAM-1, sE-selectin, interleukin-2 soluble receptor α (IL-2sRα), plasminogen activator inhibitor-1 (PAI-1) mass, cholesterol, LDL-cholesterol, and the LDL/high density lipoprotein (HDL) ratio. A multiple approach indicated that plaques were associated with age, cholesterol, and sE-selectin. Severe plaques were associated with LDL-cholesterol and disease duration. Logistic regression in the age- and sex-matched case-control study revealed that IMT-CCA was, together with the D-dimer, associated with RA per se. Conclusion: Levels of lipids and adhesion molecules were associated with the presence of atherosclerosis in RA. IMT-CCA was associated with RA per se. Disease duration could predict severe atherosclerotic plaques. Treatment with methotrexate seemed to decrease the IMT-CCA.

Angiotensin-converting enzyme insertion/deletion polymorphism modulates coronary release of tissue plasminogen activator in response to bradykinin.

The aim of this study was to assess the relationship between the angiotensin converting enzyme gene (ACE) genotype and endothelium-dependent coronary vasomotor and fibrinolytic activity. The ACE DD genotype has been reported to be a risk factor for myocardial infarction. However, the mechanism is unknown. The fibrinolytic and renin-angiotensin systems are linked via ACE at the vascular beds. We studied 73 patients (II: n=24; ID: n=37; DD: n=12) who underwent diagnostic cardiac catheterization. Graded doses of bradykinin (BK) (0.2, 0.6, 2.0 microg/min) and acetylcholine (30,100 microg/min) were administered into the left coronary artery. Coronary blood flow (CBF) was evaluated by measuring Doppler flow velocity. Blood samples were taken from the aorta (Ao) and the coronary sinus (CS). Coronary release of tPA antigen was determined as a CS-Ao gradientXCBFX[(100-hematocrit) / 100]. ACE genotypes were determined using polymerase chain reaction. The ACE genotype did not appear to affect coronary macro- and microvascular responses induced by BK or acetylcholine. Coronary tissue plasminogen activator (tPA) release induced by BK was depressed in subjects with the ACE DD genotype. ACE levels in the DD genotype were significantly higher than those in the ID or II genotype. In all of the subjects, there was a significant negative correlation between the serum level of ACE activity and net coronary tPA release in response to BK at 0.6 microg/min. In conclusions, the DD genotype of the ACE gene impairs the coronary release of tPA induced by BK.

Coagulation and fibrinolytic responses to manual versus automated snow removal.

The purpose of this study was to assess coagulation and fibrinolytic responses to snow removal. Thirteen healthy male subjects (age = 26 +/- 5 yr, height = 179.0 +/- 7.0 cm, weight = 78.7 +/- 16.1 kg, .VO2max = 54.7 +/- 8.9 mL.kg-1.min-1) underwent maximal treadmill stress testing (TM), 10 min of snow shoveling (SS), and 10 min of snow removal using an automated snow thrower (ST). Blood was collected immediately before and after each test and analyzed for von Willebrand Factor antigen (vWF:ag), tissue plasminogen activator (tPA) antigen, and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a two-factor repeated-measures analysis of variance. vWF:ag significantly increased during TM (84.7 +/- 21.7% normal preexercise, 149.0 +/- 45.6% normal postexercise) but not SS or ST. TM resulted in significant increases in tPA antigen (6.54 +/- 2.76 ng.mL-1 preexercise, 21.39 +/- 10.56 ng.mL-1 postexercise) and both SS and TM caused significant reductions in PAI-1 activity (SS = 15.1 +/- 3.8 AU.mL-1 preexercise, 13.2 +/- 4.3 AU.mL-1 postexercise; TM = 15.3 +/- 3.6 AU.mL-1 preexercise, 10.5 +/- 5.3 AU.mL-1 postexercise). Postexercise PAI-1 activity was significantly lower for TM versus SS. tPA antigen was unchanged after SS and ST, and PAI-1 activity was unchanged after ST. vWF:ag is unchanged after self-paced snow shoveling and automated snow removal in young, healthy males. Snow shoveling acutely increases fibrinolytic potential in this population, although not to the degree observed after maximal treadmill exercise.

High levels of tissue plasminogen activator (tPA) antigen precede the development of type 2 diabetes in a longitudinal population study. The Northern Sweden MONICA Study

BackgroundImpaired fibrinolysis is found in impaired glucose tolerance and type 2 diabetes, associated with components of the metabolic syndrome. There are no data concerning fibrinolysis in subjects with normal glucose tolerance that convert to diabetes.MethodsWe studied the activities of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) and the levels of tPA antigen (a marker of endothelial dysfunction) in 551 subjects with normal glucose tolerance in 1990 in relation to incident diabetes during nine years of follow-up.ResultsSubjects with diabetes at follow-up (n = 15) had significantly lower baseline tPA activity and higher PAI-1 activity and tPA antigen than non-converters. The risk of diabetes increased linearly across quartiles of PAI-activity (p = 0.007) and tPA antigen (p < 0.001) and decreased across quartiles of tPA activity (p = 0.026). The risk of diabetes with low tPA activity or high PAI-1 activity persisted after adjustment for age and sex but diminished to a non-significant level after further adjustments. The odds ratio of diabetes for high tPA antigen was 10.4 (95% confidence interval 2.7–40) adjusted for age and sex. After further adjustment for diastolic blood pressure, waist circumference, insulin, triglycerides, fasting and post load glucose the odds ratio was 6.5 (1.3–33, p = 0.024).ConclusionsImpaired fibrinolysis and endothelial dysfunction are evident in subjects with normal glucose tolerance who later develop diabetes. High tPA antigen is predictive of future diabetes independent from the metabolic syndrome.

Disasters and the heart: a review of the effects of earthquake-induced stress on cardiovascular disease.

There is growing evidence that stress contributes to cardiovascular disease. Chronic stress contributes to the atherosclerotic process through increased allostatic load, which is mediated by the neuroendocrine and immune systems (sympathetic nervous system and hypothalamus-pituitary adrenal axis) and related chronic risk factors (insulin resistance syndrome, hypertension, diabetes, and hyperlipidemia). In addition, acute stress can trigger cardiovascular events predominantly through sympathetic nervous activation and potentiation of acute risk factors (blood pressure increase, endothelial cell dysfunction, increased blood viscosity, and platelet and hemostatic activation). Earthquakes provide a good example of naturally occurring acute and chronic stress, and in this review we focus mainly on the effects of the Hanshin-Awaji earthquake on the cardiovascular system. The Hanshin-Awaji earthquake resulted in a 3-fold increase of myocardial infarctions in people living close to the epicenter, particularly in women, with most of the increase occurring in nighttime-onset events. There was also a near doubling in the frequency of strokes. These effects may be mediated by changes in hemostatic factors, as demonstrated by an increase of D-dimer, von Willebrand factor, and tissue-type plasminogen activator (tPA) antigen. Blood pressure also increased after the earthquake, and was prolonged for several weeks in patients with microalbuminuria.

Fibrinolytic capacity increases with age in healthy humans, while endothelium-dependent vasodilation is unaffected

The capacity for stimulated endothelial release of tissue-type plasminogen activator (tPA) and endothelium-dependent vasodilation is diminished in patients with cardiovascular risk factors. We examined the effect of age on desmopressin-stimulated tPA release and endothelium-dependent vasodilation, using the perfused-forearm model. Thirty-two healthy subjects were divided into quartiles by age (mean age 24, 36, 54, and 72 years, respectively). Baseline fibrinolytic parameters, baseline forearm blood flow (FBF), and increase in stimulated FBF were all similar across age. By contrast, the capacity for desmopressin- stimulated release of tPA increased linearly by age. For tPA antigen, the total amount released (area-under-the-curve) was 1015, 1282, 2139, and 2845 ng/L tissue (p = 0.011) and the peak release rates were 62, 80, 113, and 163 ng/min/L tissue (p = 0.008) in the age-quartiles, respectively. A similar significant age-related response was observed for tPA activity. We conclude that in healthy individuals there is an up-regulation of the fibrinolytic response by age.

Time course of peritoneal tissue plasminogen activator after experimental colonic surgery: effect of hyaluronan-based antiadhesive agents and bacterial peritonitis.

This study assessed the peritoneal fibrinolytic response during the first week after colonic surgery in rats with and without bacterial peritonitis, and possible modulation of the response by two hyaluronan-based antiadhesive agents. A colonic anastomosis was constructed in 90 male Wistar rats. Peritonitis was induced in another 108 rats and a colonic anastomosis was constructed after 24 h. Rats in both groups were randomized into an untreated group or one of two groups treated with hyaluronan-based agents. One-third of each group was killed at each of days 1, 3 and 7 after operation, and tissue plasminogen activator (tPA) antigen and activity were measured in peritoneal biopsies. One day after colonic surgery in normal rats, tPA antigen concentration was significantly (P < 0.005) increased, whereas tPA activity levels were normal. By day 3 after operation tPA antigen had returned to baseline values while tPA activity was significantly increased (P < 0.05). One day after inducing peritonitis tPA antigen was significantly increased (P < 0.001), while tPA activity was significantly reduced (P < 0.05). Three and seven days after colonic surgery in rats with peritonitis tPA activity was increased (P < 0.001) while tPA antigen had returned to baseline values. Neither of the hyaluronan-based agents affected peritoneal tPA antigen levels or activity after colonic surgery. Both abdominal surgery and infection caused an early increase in peritoneal tPA antigen levels, followed by an increase in tPA activity. Peritonitis severely depressed early tPA activity. Application of hyaluronan-based agents did not affect the peritoneal fibrinolytic response to surgery and/or infection.

Tissue plasminogen activator levels change with plasma fibrinogen concentrations during pregnancy.

To investigate the relationship between coagulation activities and the fibrinolytic system during normal pregnancy, we measured the plasma concentrations of coagulation factors, antithrombin III (AT III), D-dimer, tissue plasminogen activator (tPA), total protein S (TPS), and plasminogen activator inhibitor type 1 (PAI-1) in 436 apparently healthy pregnant, postpartum, and nonpregnant women. There were no significant changes in AT III, TPS, and factor XI concentrations during pregnancy and puerperium. However, factor VII, VIII, IX, and XII activities increased gradually as pregnancy progressed, reached maximum values in the third trimester, and returned to nonpregnant levels by 5-8 weeks postpartum. Plasma D-dimer levels in the third trimester of pregnancy were 1.23+/-0.42 micro g/ml, significantly higher than for the first trimester (0.34+/-0.16 micro g/ml, P<0.01). The tPA antigen levels averaged 1.8-fold higher in the late third trimester than in the first trimester; the plasma fibrinogen concentrations averaged 1.6-fold higher in the late third trimester than in the first trimester. Compared to the peak values during pregnancy, tPA levels averaged 39.8% lower and plasma fibrinogen concentrations averaged 40.0% lower at 5-8 weeks postpartum. The tPA levels correlated strongly with the plasma fibrinogen concentrations ( r=0.52, P<0.01). In short, this study shows that tPA levels change in parallel with plasma fibrinogen concentrations during and after normal pregnancy.

Effects of purified eicosapentaenoic acid and docosahexaenoic acid on platelet, fibrinolytic and vascular function in hypertensive type 2 diabetic patients

Background: Type 2 diabetes and hypertension are both associated with an increased risk of atherothrombosis. We assessed whether purified eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil have differential effects on platelet, fibrinolytic and vascular function in patients with both conditions. Methods: In a double-blind placebo-controlled trial of parallel design, 59 treated-hypertensive Type 2 diabetic men and postmenopausal women, were randomised to 4 g/day of EPA, DHA or olive oil (placebo) for 6 weeks. Collagen and PAF-stimulated platelet aggregation, collagen-stimulated thromboxane release (TXB 2), plasma tPA and PAI-1 antigens, von Willebrand factor, p-selectin, and flow-mediated and glyceryl-trinitrate-mediated dilatation of the brachial artery, were examined before and at the end of intervention. Results: Thirty-nine men and 12 women aged 61.2±1.2 year completed the study. Relative to placebo, DHA but not EPA supplementation significantly reduced collagen aggregation (16.9%, P=0.05) and TXB 2 (18.8%, P=0.03). There were no significant changes in either PAF-stimulated platelet aggregation, fibrinolytic function or vascular function in either the EPA or DHA group relative to placebo. Conclusion: Highly purified DHA may be a more effective anti-thrombotic agent than EPA. However, longer-term studies assessing morbidity and mortality are needed in order to establish if DHA contributes to reducing CHD amongst Type 2 diabetic patients with treated hypertension.