Increased plasminogen activator inhibitor activity and diabetes predict subsequent coronary events in patients with angina pectoris

Ambient temperature and cardiovascular biomarkers in a repeated-measure study in healthy adults: A novel biomarker index approach

BACKGROUND

Associations of ambient temperature with cardiovascular morbidity and mortality have been well documented in numerous epidemiological studies, but the underlying pathways remain unclear. We investigated whether systemic inflammation, coagulation, systemic oxidative stress, antioxidant activity and endothelial function may be the mechanistic pathways associated with ambient temperature.

METHODS

Forty study participants underwent repeated blood collections for 12 times in Beijing, China in 2010-2011. Ambient temperature and air pollution data were measured in central monitors close to student residences. We created five indices as the sum of weighted biomarker percentiles to represent the overall levels of 15 cardiovascular biomarkers in five pathways (systemic inflammation: hs-CRP, TNF-α and fibrinogen; coagulation: fibrinogen, PAI-1, tPA, vWF and sP-selectin; systemic oxidative stress: Ox-LDL and sCD36: antioxidant activity: EC-SOD and GPX1; and endothelial function: ET-1, E-selectin, ICAM-1 and VCAM-1). We used generalized mixed-effects models to estimate temperature effects controlling for air pollution and other covariates.

RESULTS

There were significant decreasing trends in the adjusted means of biomarker indices over the lowest to the highest quartiles of daily temperatures before blood collection. A 10°C decrease at 2-d average daily temperature were associated with increases of 2.5% [95% confidence interval (CI): 0.7, 4.2], 1.6% (95% CI: 0.1, 3.1), 2.7% (95% CI: 0.5, 4.8), 5.5% (95% CI: 3.8, 7.3) and 2.0% (95% CI: 0.3, 3.8) in the indices for systemic inflammation, coagulation, systemic oxidative stress, antioxidant activity and endothelial function, respectively. In contrast, the associations between ambient temperature and individual biomarkers had substantial variation in magnitude and strength.

CONCLUSIONS

The altered cardiovascular biomarker profiles in healthy adults associated with ambient temperature changes may help explain the temperature-related cardiovascular morbidity and mortality. The biomarker index approach may serve as a novel tool to capture ambient temperature effects.

The assessment of thrombotic markers utilizing ionic versus non-ionic contrast during coronary angiography and intervention trial

OBJECTIVE

To determine how two different types of iodinated contrast media (CM), low-osmolar ionic dimer ioxaglate (Hexabrix) and iso-osmolar non-ionic dimer iodixanol (Visipaque), affect multiple indices of hemostasis.

BACKGROUND

In vitro models demonstrate differential effects of ionic and non-ionic CM on markers of hemostasis.

METHODS

This blinded endpoint trial randomized 100 patients to ioxaglate or iodixanol. The primary endpoint was change in endogenous thrombin potential (ETP) following diagnostic angiography. Secondary endpoints included change in markers of fibrinolysis [tissue plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1)] and platelet aggregation following diagnostic angiography and percutaneous coronary intervention (PCI) with bivalirudin. Data are presented as median [interquartile range].

RESULTS

ETP significantly decreased after diagnostic angiography in both ioxaglate (baseline 1810 nM*minute [1540-2089] to post-angiography 649 nM*minute [314-1347], p < 0.001) and iodixanol groups (baseline 1682 nM*minute [1534-2147] to post-angiography 681 nM*minute [229-1237], p < 0.001), but the decrease was not different between CM (p = 0.70). There was a significant increase in ETP during PCI (n = 45), despite the use of bivalirudin, suggesting a prothrombotic effect of PCI (post-angiography 764 nM*minute [286-1283] to post-PCI 1081 nM*minute [668-1552], p = 0.02). There were no significant differential effects on tPA, PAI-1, and markers of platelet activity.

CONCLUSION

There were no significant differential effects between ioxaglate and iodixanol. Both CM led to significant reductions in thrombin generation and no significant effects on fibrinolytic activity or platelet activity, thereby contributing to a favorable antithrombotic milieu. © 2016 Wiley Periodicals, Inc.

Endogenous Fibrinolysis: An Important Mediator of Thrombus Formation and Cardiovascular Risk

Most acute cardiovascular events are attributable to arterial thrombosis. Plaque rupture or erosion stimulates platelet activation, aggregation, and thrombosis, whilst simultaneously activating enzymatic processes that mediate endogenous fibrinolysis to physiologically maintain vessel patency. Interplay between these pathways determines clinical outcome. If proaggregatory factors predominate, the thrombus may propagate, leading to vessel occlusion. However, if balanced by a healthy fibrinolytic system, thrombosis may not occur or cause lasting occlusion. Despite abundant evidence for the fibrinolytic system regulating thrombosis, it has been overlooked compared with platelet reactivity, partly due to a lack of techniques to measure it. We evaluate evidence for endogenous fibrinolysis in arterial thrombosis and review techniques to assess it, including biomarkers and global assays, such as thromboelastography and the Global Thrombosis Test. Global assays, simultaneously assessing proaggregatory and fibrinolytic pathways, could play a role in risk stratification and in identifying impaired fibrinolysis as a potential target for pharmacological modulation.

Antithrombotic effects of losartan in patients with hypertension complicated by atrial fibrillation: 4A (Angiotensin II Antagonist of platelet Aggregation in patients with Atrial fibrillation), a pilot study

Angiotensin receptor blockers (ARBs) are widely used for the treatment of hypertension. It has been reported that the ARB losartan has antiplatelet, anticoagulant and profibrinolytic effects experimentally. These properties could be desirable to treat hypertensive patients with high atherothrombotic and/or thromboembolic risk. To examine the antithrombotic effects of losartan in hypertension, 20 consecutive patients with hypertension complicated by atrial fibrillation (AF) were enrolled in this study. The patients were treated with losartan 50 mg for 8 weeks followed by 100 mg for 4 weeks. Blood samples were obtained from each patient at 0 (pretreatment), 8 and 12 weeks after initiating treatment. Platelet aggregability, plasma levels of tissue factor (TF) and type 1 plasminogen activator inhibitor (PAI-1) activity levels were measured. The area under the curve for small platelet aggregability decreased from 100 to 42.8% at 12 weeks (P<0.0001). TF levels (ng ml(-1)) and PAI-1 activity (IU ml(-1); mean±s.d.) also changed from 14.2±3.6 to 10.9±4.5 at 12 weeks (P=0.0299) and from 11.7±3.6 to 8.5±3.1 at 12 weeks (P=0.0122), respectively. Losartan inhibited platelet activity and coagulation factors in a dose- and time-dependent manner in patients with hypertension complicated by AF, whereas the fibrinolytic capacity was increased. The use of losartan could be advantageous in the treatment of hypertensive patients with high atherothrombotic risk.

Concomitant administration of different doses of simvastatin with ivabradine influence on PAI-1 and heart rate in normo- and hypercholesterolaemic rats

Ivabradine is a novel heart rate lowering agent that inhibits I_f ionic current in the sinus node and demonstrates antiischaemic and antianginal activity. The aim of the paper was to investigate the effect its dose-dependent drug-drug interaction with simvastatin inhibitor HMGCo-A has on PAI-1 blood level, heart rate and blood pressure. The experiments were performed in hyper- and normocholesterolemic Wistar rats receiving simvastatin (1 and 20 mg × kg⁻¹ bw) with ivabradine (10 mg × kg⁻¹ bw) during a 4-week period. Ivabradine exacerbated the decrease of PAI-1 in normocholesterolemic animals receiving simvastatin at a dose of 1 mg/kg bw and was not observed to have any significant influence on the PAI-1 values in rats receiving 20 mg × kg⁻¹ bw simvastatin. Ivabradine, coadministered with simvastatin given at a dose of 20 mg × kg⁻¹ bw, significantly slowed the heart rate in normocholesterolaemic and hypercholesterolaemic groups as compared to the group receiving ivabradine alone. Conclusion. The administration of ivabradine to normocholesterolaemic and hypercholesterolaemic rats receiving simvastatin significantly exacerbated the slowing of heart rate with no effect on blood pressure. The administration of ivabradine has been shown to demonstrate different effects on PAI-1 values depending on lipid disorders.

Prognostic value of plasma fibrinolysis activation markers in cardiovascular disease

The pivotal role of hypoactive endogenous fibrinolysis in the occurrence of thrombotic cardiovascular events is now well-recognized. To evaluate the diagnostic and prognostic role of impaired fibrinolysis, plasma fibrinolysis markers have been investigated in large prospective studies in both healthy individuals and patients with established coronary disease. Antigen and activity levels of components of the fibrinolytic system were measured by immunoassays, which replaced earlier global fibrinolysis tests. This review covers 45 studies in nearly 50,000 subjects, examining the association between plasma markers of fibrinolysis and coronary artery disease, to establish the usefulness of these markers in predicting future cardiovascular events. The predictive value of plasma levels of tissue-type plasminogen activator, platelet activator inhibitor-1, plasmin-antiplasmin complex, D-dimer, thrombin activatable fibrinolysis inhibitor, and lipoprotein(a) for major adverse cardiac events is highly variable and conflicting, especially after adjusting for conventional risk factors, judging from the published data in the last decade. The value of fibrinolysis activity markers is very limited in aiding diagnosis and risk stratification in the individual patient, on the basis of the weak prognostic values obtained in some studies and the lack of power in others. The physiological limitations of such markers in reflecting endogenous fibrinolysis is discussed. The emerging novel global assays of fibrinolysis will require large-scale clinical trials before their prognostic power or superiority to multiple biomarker measurements can be evaluated.

Reduced plasma fibrinolytic capacity as a potential risk factor for a first myocardial infarction in young men

Studies on the relationship between fibrinolysis and arterial thrombosis have been conflicting. Previously, we demonstrated that hypofibrinolysis, as measured by a plasma-based assay, increased the risk of venous thrombosis. The present study investigated increased clot lysis time (CLT) measured with the same assay as a risk factor for myocardial infarction in a case-control study including 421 men with a first myocardial infarction and 642 controls below 70 years. CLT was strongly associated with body-mass index, lipid levels, blood pressure and C-reactive protein. Overall, risk of myocardial infarction was 1.4-fold (95% confidence interval (CI) 1.0-1.9) increased for CLT in the fourth quartile (longest CLT) compared with the first quartile. After adjusting for cardiovascular risk factors this risk disappeared (OR 1.0, 95%CI 0.6-1.5). In men aged <50 years the association was pronounced (OR 3.2, 95%CI 1.5-6.7). After adjustment for cardiovascular risk factors the risk was nearly twofold increased (OR 1.8, 95%CI 0.7-4.8). In men aged > or = 50 years, no clear association between CLT and risk of myocardial infarction was found. Our study suggests that hypofibrinolysis increases the risk of a first myocardial infarction in young men, although the causality of this association remains to be determined.

Fibrinolysis and the risk of venous and arterial thrombosis

PURPOSE OF REVIEW

The fibrinolytic system is often regarded as just an innocent bystander in the pathogenesis of venous and arterial thrombosis, while (hyper)coagulation as a risk factor has been studied extensively. In this review, we evaluated studies that investigated the association between fibrinolysis and thrombosis.

RECENT FINDINGS

There is some evidence for an association between impaired overall fibrinolytic activity and increased risk of venous or arterial thrombosis. Plasminogen levels were found not to be related to thrombosis. Plasma levels of tissue-type plasminogen activator were related to arterial thrombosis in a number of studies but not to venous thrombosis. Thrombin activatable fibrinolysis inhibitor levels appeared to be associated with venous thrombosis. Studies on the association between thrombin activatable fibrinolysis inhibitor or plasminogen activator inhibitor-1 and arterial thrombosis had conflicting results.

SUMMARY

Current evidence on an association between fibrinolysis and thrombosis is inconclusive. Although overall assays point to an association, not all individual factors have an association with thrombosis. Most importantly, plasminogen deficiency is not related to thrombosis, which suggests that the fibrinolytic system as a whole is unimportant in the occurrence of thrombosis. Certain components of the fibrinolytic system, however, appear to be involved in processes unrelated to fibrin degradation but related to other processes important in the development of thrombosis.

Plasminogen activator inhibitor-1 4G/5G polymorphism and efficacy of reperfusion therapy in acute myocardial infarction

Plasminogen activator inhibitor-1 (PAI-1) plays a central role in the modulation of intravascular thrombosis and thrombolysis. The level of transcription and the plasma level of PAI-1 are in part determined by the 4G/5G polymorphism in the promoter region of the gene. In this study we investigate the effect of 4G/5G polymorphism on the efficacy of reperfusion therapy in acute myocardial infarction (AMI). Two hundred and ninety-three patients were enrolled in two randomized trials comparing stenting plus abciximab with thrombolysis (alteplase alone or alteplase plus abciximab) in AMI. Patients were genotyped for the PAI-1 4G/5G polymorphism with a TaqMan assay. Technetium-99m sestamibi was injected before and 1-2 weeks after reperfusion treatment. Scintigrams were used to calculate the initial perfusion defect, the final infarct size and the salvage index representing the proportion of the initial defect salvaged by reperfusion. An 18-month clinical follow-up was carried out after reperfusion treatment. The distribution of genotypes was as follows: 4G4G in 28.0%, 4G5G in 49.5% and 5G5G in 22.5% of the patients. No significant differences between the three genotypes were detected for the final infarct size (%) of the left ventricle [median (interquartile range); 13.5 (5.0--27.0) for 4G4G patients, 12.0 (5.2--24.6) for 4G5G patients and 16 (7.1--31.2) for 5G5G patients; P=0.36], the salvage index [0.49 (0.25--0.75) in 4G4G patients, 0.47 (0.18--0.73) in 4G5G patients and 0.46 (0.22--0.62) in 5G5G patients; P=0.58] and the mortality 18 months after treatment (8.5% for 4G4G patients, 7.6% for 4G5G patients and 6.1% for 5G5G patients; P=0.85). There was no association in any of the two treatment groups (stenting and thrombolysis) between the 4G/5G genotype and myocardial salvage. The PAI-1 4G/5G polymorphism has no impact on the amount of myocardial salvage achieved by reperfusion with stenting or thrombolysis in patients with AMI.

Is the effect of antihypertensive drugs on platelet aggregability and fibrinolysis clinically relevant?

Hypertension is associated with decreased fibrinolytic potential, mainly expressed as elevated plasma plasminogen activator inhibitor type 1 (PAI-1) levels, and increased platelet aggregability, which may account in part for the increased risk of atherosclerosis and its clinical complications in hypertensive patients. The effects of antihypertensive drugs on this prothrombotic state have been investigated and controversial findings have been reported, possibly because of differences in study designs, patients selected, and methodology used. Scarce and conflicting data exist about the effects of diuretics and beta-adrenoceptor antagonists on the fibrinolytic system, whereas ACE inhibitors have generally been reported to improve the fibrinolytic balance by decreasing plasma PAI-1 levels, calcium channel antagonists have been shown to increase tissue plasminogen activator (tPA) activity, and angiotensin II type 1 (AT(1)) receptor antagonists seem to exert neutral effects. beta-Adrenoceptor antagonists, calcium channel antagonists, and AT(1)-receptor antagonists have been reported to exert anti-aggregatory effects on platelets, while contrasting data exist about the influence of ACE inhibitors. Clinical implications of the changes induced by antihypertensive drugs on the fibrinolytic balance and platelet function are still debated. In particular, the question of whether these changes may translate into different degrees of cardiovascular protection in hypertensive patients remains unanswered. While awaiting more information from clinical trials, the choice of antihypertensive drugs, particularly in high-risk patients, should take into account effects beyond their BP-lowering efficacy. Selected agents should have a favorable, or at least neutral, impact on fibrinolytic function and platelet activity.

Effects of nicorandil on endogenous fibrinolytic capacity in patients with coronary artery disease

BACKGROUND

Nicorandil is a hybrid-type anti-anginal drug that combines a K(ATP) channel opener and a nitric oxide donor. Recently the IONA study reported that nicorandil improves the prognosis of patients with stable angina pectoris.

METHODS AND RESULTS

To examine the effects of nicorandil on endogenous fibrinolysis, plasma concentrations of tissue-type plasminogen activator (t-PA) antigen, type-1 plasminogen activator inhibitor (PAI-1) antigen and PAI activity were measured in consecutive 11 patients (7 men and 4 women, mean age 63 years, ranges 41-84 years) with coronary artery disease. Nicorandil (15 mg/day) was administered orally to each patient for 2 weeks. Venous blood samples were obtained from each patient before and after the administration of the drug in the early morning before eating. There were no significant changes in the plasma concentrations of t-PA (12.4+/-1.9 to 9.8+/-1.5) or PAI-1 (26.3+/-3.9 to 21.5+/-4.9) antigens (ng/ml, mean +/- SEM) before and after nicorandil administration. On the other hand, the plasma activity of PAI (IU/ml, mean +/- SEM) decreased significantly after the treatment (12.9+/-3.2 to 5.6+/-1.9, p=0.039).

CONCLUSIONS

It is well known that PAI activity determines the whole fibrinolytic capacity and oral administration of nicorandil decreased PAI activity in patients with coronary artery disease. This finding suggests that nicorandil improves the fibrinolytic capacity and may reduce the risk of coronary thrombus formation in such patients.

Vitamin E improves fibrinolytic activity in patients with coronary spastic angina

INTRODUCTION

The fibrinolytic system has a major role as a defense mechanism against thrombus formation. Net fibrinolytic activity in plasma reflects the balance between tissue-type plasminogen activator and plasminogen activator inhibitor (PAI). PAI is the main factor determining overall fibrinolytic activity.

MATERIALS AND METHODS

We examined the effects of oral administration of vitamin E, an antioxidant, on fibrinolytic activity and oxidative stress in patients with coronary spastic angina. Forty patients with coronary spastic angina were randomly assigned into two treatment groups, either vitamin E group (alpha-tocopherol acetate, 400 mg/day) or placebo group by means of computerized system. PAI activity and thioredoxin, a marker of oxidative stress, levels were measured before and at the end of 1 month treatment.

RESULTS

Before treatment, the levels of PAI activity and thioredoxin were increased in patients with coronary spastic angina as compared with control subjects (n=17) (PAI activity levels: 13.6+/-1.4 vs. 7.6+/-2.2 IU/ml, p<0.05, thioredoxin levels: 22.8+/-1.7 vs. 16.0+/-1.4 ng/ml, p<0.05). In patients with coronary spastic angina, administration of vitamin E decreased both PAI activity and thioredoxin levels (PAI activity levels: 14.7+/-1.7 to 7.5+/-1.6 IU/ml, p<0.01, thioredoxin levels: 23.3+/-2.4 to 15.1+/-2.5 ng/ml, p<0.01), whereas placebo had no effect on these variables.

CONCLUSIONS

Oral administration of vitamin E improved fibrinolytic activity and the improvement was associated with a decrease in oxidative stress. Administration of vitamin E is possible to be an effective adjunct therapy of coronary spasm in the absence of coronary atherosclerosis.

4G/4G Genotype of PAI-1 Gene Is Associated With Reduced Risk of Stroke in Elderly

Background and Purpose— Plasminogen activator inhibitor type 1 (PAI-1) is the main inhibitor of fibrinolysis, and high levels may increase the risk of cardiovascular disease. The 4G/5G polymorphism affects PAI-1 gene transcription with lower levels of plasma PAI-1 in the presence of the 5G allele. We investigated whether plasma PAI-1 and 4G/5G genotype would predict the occurrence of cardiovascular events at old age.

Methods— Relative risks for cardiovascular events and all-cause mortality were obtained in strata of PAI-1 activity and 4G/5G genotype in a population-based study of 637 Dutch elderly with 7.8 years of follow-up.

Results— The 4G/4G genotype was associated with a decreased risk of stroke (relative risk [RR]=0.4; 95% CI, 0.2 to 0.9), transient ischemic attack (RR=0.3; 95% CI, 0.1 to 0.8), and cardiovascular mortality (RR=0.5; 95% CI, 0.3 to 1.0) after adjustment for age, sex, and time of blood sampling. 4G carriers had an increased risk of myocardial infarction, but this was not statistically significant. Subjects with high plasma PAI-1 activity were at increased risk of stroke (RR=3.3 in highest versus lowest tertile; 95% CI, 1.5 to 7.1), cardiovascular mortality (RR=2.3; 95% CI, 1.2 to 4.4), and all-cause mortality (RR=1.5; 95% CI, 1.1 to 2.1).

Conclusions— Our results provide support for a protective effect of the 4G allele against stroke, which is notable given the direct relationship between stroke and PAI-1 activity. We hypothesize that a local increase in tissue PAI-1 associated with the 4G allele may stabilize plaques, thereby reducing the risk of cerebrovascular disease.

Dehydroepiandrosterone supplementation improves endothelial function and insulin sensitivity in men

The dehydroepiandrosterone (DHEA) concentration decreases with age. There is evidence that DHEA has a protective effect against age-related disorders, including cardiovascular disease. Accordingly, we examined the effect of DHEA supplementation (25 mg/d) on endothelial function, insulin sensitivity, and fibrinolytic activity in 24 men with hypercholesterolemia (mean age, 54 +/- 1 yr). All subjects were enrolled in a randomized, double-blind study. Flow-mediated dilation of brachial artery after transient occlusion, which was expressed as the percent change from the baseline value of the diameter, increased significantly with DHEA supplementation [DHEA: baseline, 3.9 +/- 0.5%; 4 wk, 6.9 +/- 0.7%; 8 wk, 7.9 +/- 0.6%; 12 wk, 8.4 +/- 0.7% (P < 0.01 vs. baseline for all, by ANOVA); placebo: 4.1 +/- 0.6%, 4.5 +/- 0.5%, 3.9 +/- 0.5%, and 4.4 +/- 0.6% (P < 0.01 for all, by ANOVA)]. There was a significant concurrent reduction in the plasma levels of plasminogen activator inhibitor type 1 during DHEA supplementation [DHEA: 9.1 +/- 2.2, 6.4 +/- 2.3, 5.5 +/- 2.8, and 5.1 +/- 2.0 IU/ml (P < 0.01 vs. baseline, by ANOVA); placebo: 9.0 +/- 2.1, 10.4 +/- 2.2, 9.5 +/- 2.2, and 9.6 +/- 2.1 IU/ml (P < 0.01, by ANOVA)]. DHEA supplementation also decreased steady state plasma glucose [DHEA: baseline, 178.9 +/- 12.2; 12 wk, 132.0 +/- 12.8 mg/dl (P < 0.01, by ANOVA); placebo: 181.0 +/- 13.8 and 179.6 +/- 12.4 mg/dl (P < 0.01, by ANOVA)]. In contrast, steady state plasma insulin did not change during the study in either group. The low dose DHEA supplementation improves vascular endothelial function and insulin sensitivity and decreases the plasminogen activator inhibitor type 1 concentration. These beneficial changes have the potential to attenuate the development of age-related disorders such as cardiovascular disease.

Identification of a tightly regulated hypoxia-response element in the promoter of human plasminogen activator inhibitor-1

Plasminogen activator inhibitor-1 (PAI-1) plays a key role in control of coagulation and tissue remodeling and has been shown to be regulated by a number of cell stimuli, among those hypoxia. In this study we characterize the hypoxia-mediated induction of PAI-1 in human hepatoma cell line HepG2. We found that PAI-1 is tightly regulated in a narrow oxygen gradient. After incubation at oxygen concentrations of 1% to 2%, a 60-fold increase in PAI-1 messenger RNA levels was observed, whereas mild hypoxic conditions of more than 3.5% did not appear to induce transcription. Moreover, increased levels of PAI-1 protein were observed after incubation at low oxygen tensions. Through sequence analysis, several putative hypoxia-response elements (HREs 1-5) were identified in the human PAI-I promoter. Reporter gene assays showed that the HRE-2 (-194 to -187) was necessary and sufficient for the hypoxia-mediated response. By electrophoretic mobility assay we observed hypoxia-dependent binding of a protein complex to the HRE-2 motif. Further analysis demonstrated that HRE-2 was specifically recognized by the hypoxia-inducible transcription factor 1alpha-arylhydrocarbon nuclear translocator complex. Taken together, our data demonstrate that hypoxia-induced transcription is mediated through HIF-1 interaction with the HRE-2 site of the human PAI-1 promoter.